ORIGINAL RESEARCH
Wheelchair Marathon Creates a Systemic Anti-inflammatory Environment in Persons With Spinal Cord Injury Yusuke Sasaki, MD,* Kazunari Furusawa, MD, PhD,† Fumihiro Tajima, MD, PhD,* Takeshi Nakamura, MD, PhD,* Ken Kouda, MD, PhD,* Nami Kanno, MD, PhD,* Takashi Kawasaki, MD, PhD,* Yasunori Umemoto, MD, PhD,* and Katuji Shimizu, MD, PhD‡
Objective: To investigate interleukin (IL)-6 and other inflammation markers in athletes with spinal cord injury (SCI) during a wheelchair marathon race.
Design: Nonrandomized study in an actual race.
full-marathon, and daily training seem to have beneficial effects on SCI through the plasma IL-6 response. Key Words: exercise, wheelchair sports, myokine, tumor necrosis factor, hsCRP (Clin J Sport Med 2014;24:295–301)
Setting: The 28th Oita International Wheelchair Marathon Race, Japan.
Participants: Twenty-eight men with SCI between T7 and L2 (16 full-marathon racers, full-group; and 12 half-marathon racers, halfgroup).
Main Outcome Measures: Plasma IL-6, tumor necrosis factor (TNF)-a, and high-sensitivity C-reactive protein (hsCRP) were measured the day before, immediately after the race, and 2 hours after the race. Results: Plasma IL-6 concentrations increased by 18.4-fold and by 9.4-fold (P , 0.05) in the full- and half-groups immediately after the race (P , 0.05), respectively, but returned to baseline at 2 hours of recovery. In contrast, plasma TNF-a and hsCRP did not change throughout the race in both groups. The fold change in plasma IL-6 immediately after the race relative to the prerace was significantly higher in the full-group than the half-group (P , 0.05). In both groups, plasma IL-6 immediately after the race did not correlate with the average wheelchair speed. Interestingly, plasma IL-6 and hsCRP before the race in the full-group, but not in half-group, correlated negatively with the average wheelchair speed (P , 0.05). Conclusions: The study demonstrated that half- and full-marathon wheelchair races increased plasma IL-6, but not TNF-a and hsCRP. Furthermore, the top athletes of the full-group had low plasma IL-6 and hsCRP at baseline. Wheelchair marathon competition, especially
Submitted for publication December 20, 2012; accepted August 6, 2013. From the *Department of Rehabilitation Medicine, School of Medicine, Wakayama Medical University, Wakayama, Japan; †Department of Rehabilitation Medicine, Kibikogen Rehabilitation Center for Employment Injuries, Kibichuo-cho, Japan; and ‡Department of Orthopedics Medicine, Gifu University, Gifu, Japan. The authors report no conflicts of interest. Corresponding Author: Fumihiro Tajima, MD, PhD, Department of Rehabilitation Medicine, School of Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8510, Japan ([email protected]). Copyright © 2014 by Lippincott Williams & Wilkins
Clin J Sport Med Volume 24, Number 4, July 2014
INTRODUCTION Today, a large proportion of individuals with spinal cord injury (SCI) can return to society and enjoy sports activities, thanks to the significant improvement in medical management, rehabilitation, and technology. However, the associated motor dysfunction requires the use of a wheelchair for mobility by the majority of persons with SCI.1 Unfortunately, the use of the wheelchair reduces daily energy expenditure.2 Thus, sports activities in SCI should be encouraged to improve the overall health status. Whereas one longitudinal study demonstrated that maximum oxygen consumption (V̇ O2max) of athletes with SCI who had continued to participate in marathon racing was almost maintained or increased over a 20-year period,3 it is well known that heart disease and type 2 diabetes are more prevalent in persons with SCI than able-bodied (AB) persons.4 Thus, persons with SCI should engage in sports activities to maintain (or even improve) functioning, participation, and health. Exercise and/or sports activities have beneficial effects even in AB persons, but the mechanism of the beneficial effects have not been fully elucidated. Pedersen et al5 suggested that cytokines and other peptides that are produced, expressed, and released by muscle fibers during exercise exert paracrine, autocrine, or endocrine effects and that they should be classified as “myokines.” Interleukin (IL)-6 was the first myokine described to promote glucose uptake and fat oxidation in skeletal muscle and to have various effects on the liver and adipose tissue. Several studies showed that IL-6 also has antiinflammatory effects with regular exercise and that it protects against chronic systemic low-grade inflammation.6–9 Myokines seem to play important roles in the protection against diseases, such as cardiovascular diseases, type 2 diabetes, dyslipidemia, and cancer.10,11 Previous studies demonstrated that plasma IL-6 concentrations in AB persons correlated with exercise intensity, duration, and the muscle mass involved in the contractile activity.12,13 www.cjsportmed.com |
295
Clin J Sport Med Volume 24, Number 4, July 2014
Sasaki et al
Several studies indicated that exercise involving a limited muscle mass failed to increase plasma IL-6, whereas running, which involves several large muscle groups, resulted in marked increase in plasma IL-6.12 We focused on the effect of wheelchair physical activity limited to the upper extremities on plasma IL-6 in persons with SCI. To our knowledge, only 2 studies have so far investigated the IL-6 response to acute bouts of exercise in subjects with SCI.14,15 Our group reported previously that 2-hour arm crank ergometer exercise at 60% V̇ O2max significantly increased plasma IL-6, but not plasma tumor necrosis factor (TNF)-a, in persons with SCI between T6 and T10.14 The wheelchair marathon race is among the hardest wheelchair sports. A previous study of athletes with SCI between T5 and L1 reported that a wheelchair full marathon is immediately followed by a decrease in natural killer (NK) cell cytotoxic activity.16 We considered that this decrease of NK cell function might be attributed to the characteristics of the wheelchair full marathon as prolonged and intensive exercise. It has been reported that only highly strenuous prolonged exercise, such as a marathon running in AB persons, results in a small increase in the plasma concentration of TNF-a in AB persons.17,18 Therefore, we need to determine whether wheelchair marathon does not only increases plasma IL-6 but also inflammation. We hypothesized that wheelchair race in athletes with SCI results in increase in plasma IL-6 without changes in inflammatory markers, such as TNF-a. To test this hypothesis, we measured the responses of IL-6 and TNF-a in athletes with SCI during and after a wheelchair marathon race.
levels excluded possible autonomic dysreflexia during the race. Before the study, each subject underwent physical and neurological examination, which confirmed the excellent health status of the upper limbs, lack of acute infection, and overall good health status, apart from the SCI-related dysfunctions. None of the subjects were on any medications that would affect the endocrine response.
Measurements and Procedures Blood samples were withdrawn from the antecubital vein in the sitting position the day before (between 1 and 3 PM), immediately after (between 1 and 3 PM) the race, and 2 hours after the race. Total blood volume in each sampling period was 6.5 mL [0.5 mL for IL-6; 0.5 mL for TNF-a; 0.5 mL for high-sensitivity C-reactive protein (hsCRP); 1.5 mL for muscle enzymes, glucose, and insulin; 1.5 mL for adrenaline, noradrenaline, dopamine, and cortisol; and 2 mL for blood cell counts]. The collected blood was immediately transferred to the laboratory for analysis.
Assays of IL-6 Blood samples for IL-6 measurement were withdrawn into glass tubes containing ethylene-diamine-tetraacetic acid and centrifuged at 3500g for 15 minutes at 48C. The plasma was stored at 2808C until analysis. High-sensitivity chemiluminescent enzyme immunoassay kit (Fujirebio Inc, Tokyo, Japan) was used for the measurement of IL-6 concentration (sensitivity: 0.2 pg/mL). All measurements were performed in duplicate.
Other Blood Tests METHODS Subjects Twenty-eight men with SCI were recruited in the present study. All subjects had participated in the 28th Oita International Wheelchair Marathon Race in Oita, Japan. Of the 28 subjects, 16 took part in the full marathon division (full-group), whereas the remaining 12 subjects participated in the half-marathon division (half-group). Table 1 summarizes the characteristics of the full- and half-groups. Although it rained continuously on the race day, all subjects completed the race. Each subject was informed of the study protocol and possible risks and signed the informed consent form before the study. The Human Research Committee of our university approved the study protocol. The spinal lesion was between T7 and L2 in the participating SCI subjects. The presence of the lesion at these TABLE 1. Characteristics of Participating Subjects n Age, y Height, m Weight, kg Level of spinal lesion
Half-Marathon Group
Full-Marathon Group
12 40.9 6 9.9 1.70 6 0.06 59.1 6 7.9 T3-L1
16 46.6 6 13.6 1.69 6 0.05 58.8 6 5.6 T3-L2
Lesion level indicates the lowest thoracic (Th) and lumber (L) spinal cord segments.
296
| www.cjsportmed.com
Total blood cell count was determined using a cell counter (MEK-5216; Nihon Kohden, Tokyo, Japan). Hematocrit (Hct) was measured by centrifugation. Enzyme-linked immunosorbent assay kit (R&D Systems, Inc, Minneapolis, Minnesota) was used to measure plasma TNF-a concentration. Serum hsCRP levels were measured by a latex enhanced immunonephelometric assay (Siemens AG, Munich, Germany). Plasma concentration of myoglobin was measured using a commercially available radioimmunoassay (TFB Factories Ltd, Tokyo, Japan). Creatine kinase (CK) and lactate dehydrogenase activities in plasma were measured by using a commercial kit (Kanto Chemical Co, Inc, Tokyo, Japan). Catecholamines were extracted from plasma using alumina and measured by high-performance liquid chromatography using a modification of the procedure described by Hunter et al.19 Plasma cortisol levels were assayed using a competitive solid phase 125I radioimmunoassay technique (Abbott Japan Co, Ltd, Tokyo, Japan).
Statistical Analysis To determine the effects of race, fold changes in IL-6 and TNF-a were expressed by the ratio of the value of each parameter measured immediately after to that before the race, as described previously.20 Normal distribution of the data of each parameter was confirmed and the summary value of each parameter was presented as mean 6 SD. One-way analysis of variance (ANOVA) with repeated measures was used to compare the number of monocytes, hormones, and cytokines. The 2014 Lippincott Williams & Wilkins
Clin J Sport Med Volume 24, Number 4, July 2014
Cytokine Response to Wheelchair Marathon
Scheffe posthoc test was used to determine differences between groups when the results of ANOVA were significant (P , 0.05). The half- and the full-groups were compared for the average speed, race time, and values of prerace, immediately after the race, 2 hours postrace, using the Mann–Whitney U test. Correlations between IL-6 concentration and race time or average wheelchair speed were calculated using a Spearman rank correlation coefficient. In all cases, statistical significance was defined as P , 0.05. All statistical analyses were performed using The Statistical Package for Social Sciences (version 11.5; SPSS, Inc, Chicago, Illinois).
RESULTS There was no significant difference in plasma IL-6 between the full-marathon (1.40 pg/mL) and half-marathon (1.36 pg/mL) group in the prerace period. Plasma IL-6 in each group significantly increased (P , 0.01) immediately after the race (half-group, 9.4-fold; full-group, 18.4-fold), and recovered at 2 hours postrace, compared with the respective prerace value (Figure 1). There were significant differences in plasma IL-6 fold change between the groups (P , 0.05) immediately after the race, and at 2 hour postrace. Plasma TNF-a and hsCRP levels did not change throughout the race in the 2 groups (Figure 2). The race time of the full-group (1.92 6 0.37 hours, 42.195 km) was significantly longer than the half-group (0.99 6 0.16 hours, 21.0975 km). However, there was no significant difference in the average wheelchair speed between the 2 groups. Plasma IL-6 levels measured immediately after the race in both groups did not correlate with the average wheelchair speed (Figure 3). IL-6 level before the race of the full-group correlated negatively with the average wheelchair speed (r = 20.59, P , 0.05, Figure 4). Plasma hsCRP level before the race of the full-group also correlated negatively with the average wheelchair speed (r = 20.56, P , 0.05) and positively with plasma IL-6 before the race (r = 0.87, P , 0.001, Figure 5). Plasma IL-6 and hsCRP
FIGURE 1. Changes in plasma IL-6 levels in wheelchair marathon racers with SCIs measured before the race, immediately after the race, and 2 hours after the race. Data are mean 6 SD. *P , 0.01 compared with before the race; †P , 0.05 compared with the half-marathon group. 2014 Lippincott Williams & Wilkins
FIGURE 2. Changes in plasma TNF-a and hsCRP levels in wheelchair marathon racers with SCIs measured before the race, immediately after the race, and 2 hours after the race. Data are mean 6 SD.
concentrations before the race of the half-group did not correlate with the average wheelchair speed. In both groups, TNF-a level before the race did not correlate with those of IL-6, hsCRP, or average wheelchair speed. Table 2 lists the race-related changes in blood cell counts and leukocyte subpopulations. Red blood cell counts, hemoglobin, and hematocrit did not change throughout the race. In both groups, leukocyte count increased markedly immediately after the race (P , 0.05) and remained elevated during recovery. Monocyte count remained constant through the study in the half-group compared with significant increases immediately after the race in the full-group (P , 0.001). Lymphocyte count increased after the race in the half-group but not in the full-group. In the half-group, the wheelchair race increased CK and myoglobin immediately after the race (P , 0.05), whereas it increased CK at 2 hours after the race and myoglobin immediately after the race in the full-group (P , 0.01, Table 3). In both groups, plasma adrenaline and noradrenaline levels increased significantly immediately after the race (P , 0.01) but recovered at 2 hours after the race (Table 3). There was no correlation between plasma IL-6 and adrenaline levels. In both groups, plasma cortisol increased significantly immediately after the race (P , 0.01) and returned later to the baseline (before the race, Table 3). Plasma glucose and insulin levels remained constant throughout the study in both groups (Table 3). www.cjsportmed.com |
297
Clin J Sport Med Volume 24, Number 4, July 2014
Sasaki et al
FIGURE 4. Correlation between plasma IL-6 levels before the race (prerace) and average wheelchair speed of the fullmarathon group in wheelchair marathon racers with SCIs. Data analyzed by Spearman correlation analysis.
FIGURE 3. Relationship between plasma IL-6 levels immediately after the race (postrace) and average wheelchair speed in wheelchair marathon racers with SCIs.
DISCUSSION
The present study is the first to examine IL-6 response to wheelchair long distance race in SCI. The major findings of the present study were as follows: (1) IL-6 in both the halfand full-race groups increased after the race compared with stable values for TNF-a and hsCRP, (2) the magnitude of increase in IL-6 at 2 hours after the race was greater in the full-marathon group than the half-marathon, and (3) IL-6 and hsCRP before the race correlated negatively with average wheelchair speed in the full-group but not in the half-group. In AB persons, running, which involves several large muscles, is the mode of exercise associated with the most dramatic increase in plasma IL-6.12 Since contracting skeletal muscle per se is an important source of circulating IL-6 in the AB,21,22 it is not surprising that exercise involving a limited muscle mass in the AB, for example, muscles of the upper extremities, may be insufficient to increase plasma IL-6 above
298
| www.cjsportmed.com
pre-exercise level.23–25 However, the present study and 2-hour arm crank ergometer exercise in SCI14 as well as arm crank ergometer exercise in the AB14 demonstrated that exercise involving the upper arm muscle mass also increases plasma IL-6 above the pre-exercise level. Plasma IL-6 response is related to exercise intensity, duration, and the muscle mass involved in the contractile activity.12,13 Exercise intensity indirectly represents the muscle mass involved in the contractile activity.11 Therefore, the increase in plasma IL-6 level during the full- and half-wheelchair marathon race might be attributed to the sufficient intensity and duration of the exercise. The present results also suggest that bulk muscle mass of the upper extremities of athletes with SCI might compensate for the disadvantage. In the present study, the plasma IL-6 fold change immediately after the race relative to the prerace value was significantly higher in the full-group than the half-group, although wheelchair speed, that is, exercise intensity, was identical in the 2 groups. Indeed, the race time for the fullgroup was almost double than that for the half-group. These findings suggest that exercise duration could be more important than exercise intensity with respect to increases in plasma IL-6 levels during exercise. In fact, Fischer12 reported that exercise duration is the single most important factor determining the postexercise plasma IL-6 fold change in AB persons. Based on the 67 exercise trials in about 800 subjects, more than 50% of the variation in plasma IL-6 following exercise could be explained by exercise duration alone.12 The physiological stimulus of exercise duration for muscle-derived IL-6 in SCI should be similar to that in the AB. In most studies, TNF-a does not change during exercise.26 The present results of TNF-a in the full- and half-groups are in agreement with those of previous studies. Only highly strenuous, prolonged exercise, such as marathon running, results in a small increase in TNF-a plasma concentrations.17,18 Starkie et al18 investigated changes in plasma TNF-a and IL-6 in AB 2014 Lippincott Williams & Wilkins
Clin J Sport Med Volume 24, Number 4, July 2014
Cytokine Response to Wheelchair Marathon
TABLE 2. Blood Cell Counts and Leukocyte Subpopulations
Red blood cells, ·1012/L Half-group Full-group Hemoglobin, ·105/L Half-group Full-group Hematocrit, % Half-group Full-group Leukocytes, ·109/L Half-group Full-group Neutrophils, ·109/L Half-group Full-group Lymphocytes, ·109/L Half-group Full-group Monocytes, ·109/L Half-group Full-group
Prerace
Postrace
2 Hours Postrace
5.00 6 0.39 4.95 6 0.44
5.23 6 0.43 5.00 6 0.45
5.25 6 0.50 4.86 6 0.42
15.4 6 1.1 15.4 6 1.4
16.3 6 1.2 15.4 6 1.3
16.0 6 1.1 15.0 6 1.2
45.1 6 2.7 45.6 6 3.2
47.9 6 3.1 46.3 6 3.0
47.7 6 3.5 44.9 6 2.7
5.95 6 1.26 6.00 6 1.36
12.6 6 3.11* 15.3 6 3.25*
12.9 6 3.45* 14.8 6 3.33*
3.65 6 1.03 3.62 6 1.10
9.30 6 2.30* 12.7 6 3.02*
11.3 6 3.14 12.3 6 3.07*
1.78 6 0.55 1.91 6 0.57
2.72 6 1.27† 1.89 6 0.58
1.11 6 0.30 1.80 6 0.60
0.30 6 0.09 0.27 6 0.10
0.42 6 0.13 0.58 6 0.19*
0.47 6 0.20† 0.57 6 0.17*
Values are expressed as mean 6 SD. *P , 0.01, compared with prerace. †P , 0.05.
FIGURE 5. A, Correlation between plasma hsCRP levels before the race and average wheelchair speed of the full-marathon group of wheelchair marathon racers with SCIs. B, Correlation between plasma hsCRP levels before the race and plasma IL-6 levels of the full-marathon group of wheelchair marathon racers with SCIs. Data analyzed by Spearman correlation analysis.
subjects who participated in the Melbourne Marathon. In their study, plasma IL-6 and TNF-a concentrations were elevated after exercise and 2 hours after exercise, and the increase in the former was maintained at 24 hours after exercise. The results of the present study showed increases in plasma IL-6 after wheelchair full- and half-marathon race compared with stable TNF-a and hsCRP levels. Wheelchair full-marathon race is a very strenuous and high-intensity exercise; however, it is less strenuous compared with the full-marathon race in the AB. The stable levels of TNF-a and hsCRP suggest that both races were not extremely strenuous exercise for the participants with SCI. The reported rise in serum CK level in the AB after a full-marathon race was 26-fold;27 however, that in the present study was less than 2 to 3 times the baseline. Myoglobin increased immediately after the race and remained elevated until 2 hours after race. Myoglobin level was measured until 2 hours after the race in the present study, but we reported 2014 Lippincott Williams & Wilkins
previously that myoglobin increased immediately after the wheelchair full-marathon race and recovered at 24 hours after the race.28 It is possible that the increases in CK and myoglobin after the wheelchair race could be induced by increased sarcolemmal permeability rather than being a byproduct of muscle damage.29 In the present study, although the increase in myoglobin was still elevated 2 hours after the race, plasma IL-6 level recovered 2 hours after the race. Thus, we assumed that the response of plasma IL-6 in the present study is not associated with damage to the exercise muscles. It is well known that monocytes can produce IL-6 in inflammation state in AB persons. Several studies demonstrated that the expression level of IL-6 mRNA in monocytes, the blood mononuclear cells responsible for the increase in plasma IL-6 during sepsis, does not increase after exercise.30,31 Pedersen and Febbraio26 confirmed recently that monocytes are not the source of exercise-induced increase in plasma IL-6. In the present study, the number of plasma monocytes and plasma IL-6 level increased immediately after the fullmarathon race. Furthermore, plasma IL-6 concentration returned to the baseline level at 2 hours after the race, whereas monocyte count remained elevated until 2 hours after the race. Although the monocyte count in the half-group remained stable throughout the study, the mean plasma IL-6 concentration in this group increased immediately after the race. The results of our study are compatible with those of previous studies and strongly suggest that the source of increased plasma IL-6 during wheelchair marathon is not mainly due to monocytes. www.cjsportmed.com |
299
Clin J Sport Med Volume 24, Number 4, July 2014
Sasaki et al
TABLE 3. Concentrations of Plasma Catecholamine, Cortisol, Glucose, Insulin, CK, and Myoglobin
Adrenaline, nmol/L Half-group Full-group Noradrenaline, nmol/L Half-group Full-group Cortisol, nmol/L Half-group Full-group Glucose, mmol/L Half-group Full-group Insulin, mU/L Half-group Full-group CK, U/L Half-group Full-group Myoglobin, nmol/L Half-group Full-group
Prerace
Postrace
2 Hours Postrace
0.26 6 0.15 0.32 6 0.14
1.73 6 1.46* 1.52 6 1.24*
0.37 6 0.27 0.42 6 0.26
2.94 6 1.15 2.84 6 1.11
9.22 6 4.36* 6.79 6 2.34*
4.23 6 1.97 4.24 6 1.72
401 6 94 442 6 133
851 6 282* 701 6 288*
379 6 151 344 6 172
5.45 6 1.18 6.23 6 1.23
6.59 6 1.76 5.39 6 1.16
5.43 6 1.34 6.25 6 1.47
19.2 6 27.5 31.0 6 39.0
25.5 6 16.0 17.1 6 10.4
43.1 6 33.8 29.7 6 24.5
287 6 218 181 6 159
495 6 292† 320 6 201
258 6 122 439 6 276*
2.32 6 0.73 2.04 6 0.67
9.30 6 3.28† 15.6 6 11.4*
15.2 6 9.20* 21.2 6 15.5*
Values are expressed as mean 6 SD. *P , 0.01, compared with prerace. †P , 0.05.
The full-marathon group, but not the half-group, showed negative correlations between baseline plasma IL-6 and hsCRP levels with the average wheelchair speed. Fullmarathon athletes have to do hard training to complete the race. However, the half-marathon athletes can participate in the race without strenuous training. The wheelchair speed of the full-group, but not the half-group, correlates closely with the daily training. For this reason, IL-6 before the race correlated with wheelchair speed only in the full-marathon group. The results of the present study suggest that athletes who were free of any medical complications and had undergone adequate training for participation in the wheelchair fullmarathon race had low plasma IL-6 and hsCRP levels at rest. The present study has certain limitations. Recent studies described the effects of exercise on other anti-inflammatory cytokines, such as IL-1ra, IL-8, IL-10, and IL-15. However, we could not measure the levels of these anti-inflammatory cytokines in the present study. One reason was the importance of IL-6 as a muscle-derived cytokine. Another reason was that we were not allowed to collect a large quantity of blood samples from the subjects, for fear of the ethics committee that such intervention could be an infringement to the race participation or influence the race outcome at the 28th Oita International Wheelchair Marathon Race. For this reason, the present study examined only changes in IL-6 as a representative anti-inflammatory cytokine. Further studies are needed to explore other muscle-derived interleukins.
CONCLUSIONS In the present study, red blood cell count, hemoglobin, and hematocrit remained unchanged throughout the race. The results suggest that dehydration did not occur during the race, a factor that may depend on whether subjects are allowed to eat and drink freely before and during the race. Therefore, there is no effect for hemoconcentration on our data throughout the race. During resting conditions, IL-6 is not produced by skeletal muscles32 and 10% to 35% of the body IL-6 is produced by adipose tissues.33 Due to the high plasma IL-6 levels at rest in some patients with metabolic diseases, this cytokine is considered to be involved in chronic diseases and a proinflammatory cytokine that promotes insulin resistance and hyperlipidemia.26 However, Pedersen and Febbraio26 proposed that the high level of IL-6 at rest could represent a “defense” mechanism against the proinflammatory actions of TNF-a. In 84 healthy AB persons, Fischer et al34 investigated whether the basal levels of IL-6 and C-reactive protein (CRP) reflect the degree of regular physical activity compared with other markers of inflammation associated with lifestylerelated morbidity. They demonstrated that low levels of IL-6 and CRP, but not TNF-a, reflect regular physical activity. Therefore, we speculate that the low levels of IL-6 before the race reflect the health status in SCI. However, the plasma level of IL-6 in the full-group was similar to that of the halfgroup at baseline (before the race). Considered together, these findings suggest that plasma IL-6 was at low levels before the race even in the half-marathon group.
300
| www.cjsportmed.com
The present study demonstrated that upper arm wheelchair marathon induced increases in plasma IL-6 but had no effect on TNF-a and hsCRP. Furthermore, before the race, the top athletes of the full-marathon group had low plasma IL-6 and hsCRP levels. Our results suggest that wheelchair marathon race, especially the full marathon, and daily training might have beneficial effects on athletes with SCI through the plasma IL-6 response. It is anticipated that sports activities that induce IL-6 response help prevent heart diseases and type 2 diabetes even in SCI persons. We recommend that SCI individuals participate in various sports activities.
ACKNOWLEDGMENTS The authors thank Drs Masaki Goto, Motohiko Banno, and Tomoyuki Ito for the clinical assistance. They also thank Dr Faiq G. Issa for the careful reading and editing of the manuscript. REFERENCES 1. Post MW, van Asbeck FW, van Dijk AJ, et al. Services for spinal cord injured: availability and satisfaction. Spinal Cord. 1997;35:109–115. 2. Buchholz AC, Pencharz PB. Energy expenditure in chronic spinal cord injury. Curr Opin Clin Nutr Metab Care. 2004;7:635–639. 3. Shiba S, Okawa H, Uenishi H, et al. Longitudinal changes in physical capacity over 20 years in athletes with spinal cord injury. Arch Phys Med Rehabil. 2010;91:1262–1266. 4. Bauman WA, Spungen AM. Coronary heart disease in individuals with spinal cord injury: assessment of risk factors. Spinal Cord. 2008;46:466– 476.
2014 Lippincott Williams & Wilkins
Clin J Sport Med Volume 24, Number 4, July 2014 5. Pedersen BK, Akerström TC, Nielsen AR, et al. Role of myokines in exercise and metabolism. J Appl Physiol. 2007;103:1093–1098. 6. Fiers W. Tumor necrosis factor. Characterization at the molecular, cellular and in vivo level. FEBS Lett. 1991;285:199–212. 7. Matthys P, Mitera T, Heremans H, et al. Anti-gamma interferon and antiinterleukin-6 antibodies affect staphylococcal enterotoxin B-induced weight loss, hypoglycemia, cytokine release in D-galactosamine-sensitized and unsensitized mice. Infect Immun. 1995;63:1158–1164. 8. Mizuhara H, O’Neill E, Seki N, et al. T cell activation-associated hepatic injury: mediation by tumor necrosis factors and protection by interleukin6. J Exp Med. 1994;179:1529–1537. 9. Starkie R, Ostrowski SR, Jauffred S, et al. Exercise and IL-6 infusion inhibit endotoxin-induced TNF-alpha production in humans. FASEB J. 2003;17:884–886. 10. Choy EH, Isenberg DA, Garrood T, et al. Therapeutic benefit of blocking interleukin-6 activity with an anti-interleukin-6 receptor monoclonal antibody in rheumatoid arthritis: a randomized, double-blind, placebo-controlled, dose-escalation trial. Arthritis Rheum. 2002;46:3143–3150. 11. Nishimoto N, Yoshizaki K, Miyasaka N, et al. Treatment of rheumatoid arthritis with humanized anti-interleukin-6 receptor antibody: a multicenter, double-blind, placebo-controlled trial. Arthritis Rheum. 2004;50: 1761–1769. 12. Fischer CP. Interleukin-6 in acute exercise and training: what is the biological relevance? Exerc Immunol Rev. 2006;12:6–33. 13. Ostrowski K, Schjerling P, Pedersen BK. Physical activity and plasma interleukin-6 in humans: effect of intensity of exercise. Eur J Appl Physiol. 2000;83:512–515. 14. Umemoto Y, Furusawa K, Kouda K, et al. Plasma IL-6 levels during arm exercise in persons with spinal cord injury. Spinal Cord. 2011;49:1182– 1187. 15. Kouda K, Furusawa K, Sugiyama H, et al. Does 20-min arm crank ergometer exercise increase plasma interleukin-6 in individuals with cervical spinal cord injury? Eur J Appl Physiol. 2012;112:597–604. 16. Furusawa K, Tajima F, Tanaka Y, et al. Short-term attenuation of natural killer cell cytotoxic activity in wheelchair marathoners with paraplegia. Arch Phys Med Rehabil. 1998;79:1116–1121. 17. Bruunsgaard H, Hartkopp A, Mohr T, et al. In vivo cell-mediated immunity and vaccination response following prolonged, intense exercise. Med Sci Sports Exerc. 1997;29:1176–1181. 18. Starkie RL, Rolland J, Angus DJ, et al. Circulating monocytes are not the source of elevations in plasma IL-6 and TNF-alpha levels after prolonged running. Am J Physiol Cell Physiol. 2001;280:769–774. 19. Hunter LW, Rorie DK, Yaksh TL, et al. Concurrent separation of catecholamines, dihydroxyphenylglycol, vasoactive intestinal peptide, and
2014 Lippincott Williams & Wilkins
Cytokine Response to Wheelchair Marathon
20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34.
neuropeptide Y in superfusate and tissue extract. Anal Biochem. 1988; 173:340–352. Ostrowski K, Rohde T, Asp S, et al. Pro- and anti-inflammatory cytokine balance in strenuous exercise in humans. J Physiol. 1999;515:287–291. Fischer CP, Hiscock NJ, Penkowa M, et al. Supplementation with vitamins C and E inhibits the release of interleukin-6 from contracting human skeletal muscle. J Physiol. 2004;558:633–645. Steensberg A, van Hall G, Osada T, et al. Production of interleukin-6 in contracting human skeletal muscles can account for the exercise-induced increase in plasma interleukin-6. J Physiol. 2000;529:237–242. Bergfors M, Barnekow-Bergkvist M, Kalezic N, et al. Short-term effects of repetitive arm work and dynamic exercise on glucose metabolism and insulin sensitivity. Acta Physiol Scand. 2005;183:345–356. Hirose L, Nosaka K, Newton M, et al. Changes in inflammatory mediators following eccentric exercise of the elbow flexors. Exerc Immunol Rev. 2004;10:75–90. Nosaka K, Clarkson PM. Changes in indicators of inflammation after eccentric exercise of the elbow flexors. Med Sci Sports Exerc. 1996;28: 953–961. Pedersen BK, Febbraio MA. Muscle as an endocrine organ: focus on muscle-derived interleukin-6. Physiol Rev. 2008;88:1379–1406. Siegel AJ, Silverman LM, Holman BL. Elevated creatine kinase MB isoenzyme levels in marathon runners. Normal myocardial scintigrams suggest noncardiac source. JAMA. 1981;246:2049–2051. Ide M, Tajima F, Furusawa K, et al. Wheelchair marathon racing causes striated muscle distress in individuals with spinal cord injury. Arch Phys Med Rehabil. 1999;80:324–327. Kuipers H. Exercise-induced muscle damage. Int J Sports Med. 1994;15: 132–135. Ullum H, Haahr PM, Diamant M, et al. Bicycle exercise enhances plasma IL-6 but does not change IL-1 alpha, IL-1 beta, IL-6, or TNF-alpha premRNA in BMNC. J Appl Physiol. 1994;77:93–97. Moldoveanu AI, Shephard RJ, Shek PN. Exercise elevates plasma levels but not gene expression of IL-1beta, IL-6, TNF-alpha in blood mononuclear cells. J Appl Physiol. 2000;89:1499–1504. Hiscock N, Chan MH, Bisucci T, et al. Skeletal myocytes are a source of interleukin-6 mRNA expression and protein release during contraction: evidence of fiber type specificity. FASEB J. 2004;18:992–994. Mohamed-Ali V, Goodrick S, Rawesh A, et al. Subcutaneous adipose tissue releases interleukin-6, but not tumor necrosis factor-alpha, in vivo. J Clin Endocrinol Metab. 1997;82:4196–4200. Fischer CP, Berntsen A, Perstrup LB, et al. Plasma levels of interleukin-6 and C-reactive protein are associated with physical inactivity independent of obesity. Scand J Med Sci Sports. 2007;17:580–587.
www.cjsportmed.com |
301
Wheelchair Marathon Creates a Systemic Anti-inflammatory Environment in Persons With Spinal Cord Injury Yusuke Sasaki, MD,* Kazunari Furusawa, MD, PhD,† Fumihiro Tajima, MD, PhD,* Takeshi Nakamura, MD, PhD,* Ken Kouda, MD, PhD,* Nami Kanno, MD, PhD,* Takashi Kawasaki, MD, PhD,* Yasunori Umemoto, MD, PhD,* and Katuji Shimizu, MD, PhD‡
Objective: To investigate interleukin (IL)-6 and other inflammation markers in athletes with spinal cord injury (SCI) during a wheelchair marathon race.
Design: Nonrandomized study in an actual race.
full-marathon, and daily training seem to have beneficial effects on SCI through the plasma IL-6 response. Key Words: exercise, wheelchair sports, myokine, tumor necrosis factor, hsCRP (Clin J Sport Med 2014;24:295–301)
Setting: The 28th Oita International Wheelchair Marathon Race, Japan.
Participants: Twenty-eight men with SCI between T7 and L2 (16 full-marathon racers, full-group; and 12 half-marathon racers, halfgroup).
Main Outcome Measures: Plasma IL-6, tumor necrosis factor (TNF)-a, and high-sensitivity C-reactive protein (hsCRP) were measured the day before, immediately after the race, and 2 hours after the race. Results: Plasma IL-6 concentrations increased by 18.4-fold and by 9.4-fold (P , 0.05) in the full- and half-groups immediately after the race (P , 0.05), respectively, but returned to baseline at 2 hours of recovery. In contrast, plasma TNF-a and hsCRP did not change throughout the race in both groups. The fold change in plasma IL-6 immediately after the race relative to the prerace was significantly higher in the full-group than the half-group (P , 0.05). In both groups, plasma IL-6 immediately after the race did not correlate with the average wheelchair speed. Interestingly, plasma IL-6 and hsCRP before the race in the full-group, but not in half-group, correlated negatively with the average wheelchair speed (P , 0.05). Conclusions: The study demonstrated that half- and full-marathon wheelchair races increased plasma IL-6, but not TNF-a and hsCRP. Furthermore, the top athletes of the full-group had low plasma IL-6 and hsCRP at baseline. Wheelchair marathon competition, especially
Submitted for publication December 20, 2012; accepted August 6, 2013. From the *Department of Rehabilitation Medicine, School of Medicine, Wakayama Medical University, Wakayama, Japan; †Department of Rehabilitation Medicine, Kibikogen Rehabilitation Center for Employment Injuries, Kibichuo-cho, Japan; and ‡Department of Orthopedics Medicine, Gifu University, Gifu, Japan. The authors report no conflicts of interest. Corresponding Author: Fumihiro Tajima, MD, PhD, Department of Rehabilitation Medicine, School of Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8510, Japan ([email protected]). Copyright © 2014 by Lippincott Williams & Wilkins
Clin J Sport Med Volume 24, Number 4, July 2014
INTRODUCTION Today, a large proportion of individuals with spinal cord injury (SCI) can return to society and enjoy sports activities, thanks to the significant improvement in medical management, rehabilitation, and technology. However, the associated motor dysfunction requires the use of a wheelchair for mobility by the majority of persons with SCI.1 Unfortunately, the use of the wheelchair reduces daily energy expenditure.2 Thus, sports activities in SCI should be encouraged to improve the overall health status. Whereas one longitudinal study demonstrated that maximum oxygen consumption (V̇ O2max) of athletes with SCI who had continued to participate in marathon racing was almost maintained or increased over a 20-year period,3 it is well known that heart disease and type 2 diabetes are more prevalent in persons with SCI than able-bodied (AB) persons.4 Thus, persons with SCI should engage in sports activities to maintain (or even improve) functioning, participation, and health. Exercise and/or sports activities have beneficial effects even in AB persons, but the mechanism of the beneficial effects have not been fully elucidated. Pedersen et al5 suggested that cytokines and other peptides that are produced, expressed, and released by muscle fibers during exercise exert paracrine, autocrine, or endocrine effects and that they should be classified as “myokines.” Interleukin (IL)-6 was the first myokine described to promote glucose uptake and fat oxidation in skeletal muscle and to have various effects on the liver and adipose tissue. Several studies showed that IL-6 also has antiinflammatory effects with regular exercise and that it protects against chronic systemic low-grade inflammation.6–9 Myokines seem to play important roles in the protection against diseases, such as cardiovascular diseases, type 2 diabetes, dyslipidemia, and cancer.10,11 Previous studies demonstrated that plasma IL-6 concentrations in AB persons correlated with exercise intensity, duration, and the muscle mass involved in the contractile activity.12,13 www.cjsportmed.com |
295
Clin J Sport Med Volume 24, Number 4, July 2014
Sasaki et al
Several studies indicated that exercise involving a limited muscle mass failed to increase plasma IL-6, whereas running, which involves several large muscle groups, resulted in marked increase in plasma IL-6.12 We focused on the effect of wheelchair physical activity limited to the upper extremities on plasma IL-6 in persons with SCI. To our knowledge, only 2 studies have so far investigated the IL-6 response to acute bouts of exercise in subjects with SCI.14,15 Our group reported previously that 2-hour arm crank ergometer exercise at 60% V̇ O2max significantly increased plasma IL-6, but not plasma tumor necrosis factor (TNF)-a, in persons with SCI between T6 and T10.14 The wheelchair marathon race is among the hardest wheelchair sports. A previous study of athletes with SCI between T5 and L1 reported that a wheelchair full marathon is immediately followed by a decrease in natural killer (NK) cell cytotoxic activity.16 We considered that this decrease of NK cell function might be attributed to the characteristics of the wheelchair full marathon as prolonged and intensive exercise. It has been reported that only highly strenuous prolonged exercise, such as a marathon running in AB persons, results in a small increase in the plasma concentration of TNF-a in AB persons.17,18 Therefore, we need to determine whether wheelchair marathon does not only increases plasma IL-6 but also inflammation. We hypothesized that wheelchair race in athletes with SCI results in increase in plasma IL-6 without changes in inflammatory markers, such as TNF-a. To test this hypothesis, we measured the responses of IL-6 and TNF-a in athletes with SCI during and after a wheelchair marathon race.
levels excluded possible autonomic dysreflexia during the race. Before the study, each subject underwent physical and neurological examination, which confirmed the excellent health status of the upper limbs, lack of acute infection, and overall good health status, apart from the SCI-related dysfunctions. None of the subjects were on any medications that would affect the endocrine response.
Measurements and Procedures Blood samples were withdrawn from the antecubital vein in the sitting position the day before (between 1 and 3 PM), immediately after (between 1 and 3 PM) the race, and 2 hours after the race. Total blood volume in each sampling period was 6.5 mL [0.5 mL for IL-6; 0.5 mL for TNF-a; 0.5 mL for high-sensitivity C-reactive protein (hsCRP); 1.5 mL for muscle enzymes, glucose, and insulin; 1.5 mL for adrenaline, noradrenaline, dopamine, and cortisol; and 2 mL for blood cell counts]. The collected blood was immediately transferred to the laboratory for analysis.
Assays of IL-6 Blood samples for IL-6 measurement were withdrawn into glass tubes containing ethylene-diamine-tetraacetic acid and centrifuged at 3500g for 15 minutes at 48C. The plasma was stored at 2808C until analysis. High-sensitivity chemiluminescent enzyme immunoassay kit (Fujirebio Inc, Tokyo, Japan) was used for the measurement of IL-6 concentration (sensitivity: 0.2 pg/mL). All measurements were performed in duplicate.
Other Blood Tests METHODS Subjects Twenty-eight men with SCI were recruited in the present study. All subjects had participated in the 28th Oita International Wheelchair Marathon Race in Oita, Japan. Of the 28 subjects, 16 took part in the full marathon division (full-group), whereas the remaining 12 subjects participated in the half-marathon division (half-group). Table 1 summarizes the characteristics of the full- and half-groups. Although it rained continuously on the race day, all subjects completed the race. Each subject was informed of the study protocol and possible risks and signed the informed consent form before the study. The Human Research Committee of our university approved the study protocol. The spinal lesion was between T7 and L2 in the participating SCI subjects. The presence of the lesion at these TABLE 1. Characteristics of Participating Subjects n Age, y Height, m Weight, kg Level of spinal lesion
Half-Marathon Group
Full-Marathon Group
12 40.9 6 9.9 1.70 6 0.06 59.1 6 7.9 T3-L1
16 46.6 6 13.6 1.69 6 0.05 58.8 6 5.6 T3-L2
Lesion level indicates the lowest thoracic (Th) and lumber (L) spinal cord segments.
296
| www.cjsportmed.com
Total blood cell count was determined using a cell counter (MEK-5216; Nihon Kohden, Tokyo, Japan). Hematocrit (Hct) was measured by centrifugation. Enzyme-linked immunosorbent assay kit (R&D Systems, Inc, Minneapolis, Minnesota) was used to measure plasma TNF-a concentration. Serum hsCRP levels were measured by a latex enhanced immunonephelometric assay (Siemens AG, Munich, Germany). Plasma concentration of myoglobin was measured using a commercially available radioimmunoassay (TFB Factories Ltd, Tokyo, Japan). Creatine kinase (CK) and lactate dehydrogenase activities in plasma were measured by using a commercial kit (Kanto Chemical Co, Inc, Tokyo, Japan). Catecholamines were extracted from plasma using alumina and measured by high-performance liquid chromatography using a modification of the procedure described by Hunter et al.19 Plasma cortisol levels were assayed using a competitive solid phase 125I radioimmunoassay technique (Abbott Japan Co, Ltd, Tokyo, Japan).
Statistical Analysis To determine the effects of race, fold changes in IL-6 and TNF-a were expressed by the ratio of the value of each parameter measured immediately after to that before the race, as described previously.20 Normal distribution of the data of each parameter was confirmed and the summary value of each parameter was presented as mean 6 SD. One-way analysis of variance (ANOVA) with repeated measures was used to compare the number of monocytes, hormones, and cytokines. The 2014 Lippincott Williams & Wilkins
Clin J Sport Med Volume 24, Number 4, July 2014
Cytokine Response to Wheelchair Marathon
Scheffe posthoc test was used to determine differences between groups when the results of ANOVA were significant (P , 0.05). The half- and the full-groups were compared for the average speed, race time, and values of prerace, immediately after the race, 2 hours postrace, using the Mann–Whitney U test. Correlations between IL-6 concentration and race time or average wheelchair speed were calculated using a Spearman rank correlation coefficient. In all cases, statistical significance was defined as P , 0.05. All statistical analyses were performed using The Statistical Package for Social Sciences (version 11.5; SPSS, Inc, Chicago, Illinois).
RESULTS There was no significant difference in plasma IL-6 between the full-marathon (1.40 pg/mL) and half-marathon (1.36 pg/mL) group in the prerace period. Plasma IL-6 in each group significantly increased (P , 0.01) immediately after the race (half-group, 9.4-fold; full-group, 18.4-fold), and recovered at 2 hours postrace, compared with the respective prerace value (Figure 1). There were significant differences in plasma IL-6 fold change between the groups (P , 0.05) immediately after the race, and at 2 hour postrace. Plasma TNF-a and hsCRP levels did not change throughout the race in the 2 groups (Figure 2). The race time of the full-group (1.92 6 0.37 hours, 42.195 km) was significantly longer than the half-group (0.99 6 0.16 hours, 21.0975 km). However, there was no significant difference in the average wheelchair speed between the 2 groups. Plasma IL-6 levels measured immediately after the race in both groups did not correlate with the average wheelchair speed (Figure 3). IL-6 level before the race of the full-group correlated negatively with the average wheelchair speed (r = 20.59, P , 0.05, Figure 4). Plasma hsCRP level before the race of the full-group also correlated negatively with the average wheelchair speed (r = 20.56, P , 0.05) and positively with plasma IL-6 before the race (r = 0.87, P , 0.001, Figure 5). Plasma IL-6 and hsCRP
FIGURE 1. Changes in plasma IL-6 levels in wheelchair marathon racers with SCIs measured before the race, immediately after the race, and 2 hours after the race. Data are mean 6 SD. *P , 0.01 compared with before the race; †P , 0.05 compared with the half-marathon group. 2014 Lippincott Williams & Wilkins
FIGURE 2. Changes in plasma TNF-a and hsCRP levels in wheelchair marathon racers with SCIs measured before the race, immediately after the race, and 2 hours after the race. Data are mean 6 SD.
concentrations before the race of the half-group did not correlate with the average wheelchair speed. In both groups, TNF-a level before the race did not correlate with those of IL-6, hsCRP, or average wheelchair speed. Table 2 lists the race-related changes in blood cell counts and leukocyte subpopulations. Red blood cell counts, hemoglobin, and hematocrit did not change throughout the race. In both groups, leukocyte count increased markedly immediately after the race (P , 0.05) and remained elevated during recovery. Monocyte count remained constant through the study in the half-group compared with significant increases immediately after the race in the full-group (P , 0.001). Lymphocyte count increased after the race in the half-group but not in the full-group. In the half-group, the wheelchair race increased CK and myoglobin immediately after the race (P , 0.05), whereas it increased CK at 2 hours after the race and myoglobin immediately after the race in the full-group (P , 0.01, Table 3). In both groups, plasma adrenaline and noradrenaline levels increased significantly immediately after the race (P , 0.01) but recovered at 2 hours after the race (Table 3). There was no correlation between plasma IL-6 and adrenaline levels. In both groups, plasma cortisol increased significantly immediately after the race (P , 0.01) and returned later to the baseline (before the race, Table 3). Plasma glucose and insulin levels remained constant throughout the study in both groups (Table 3). www.cjsportmed.com |
297
Clin J Sport Med Volume 24, Number 4, July 2014
Sasaki et al
FIGURE 4. Correlation between plasma IL-6 levels before the race (prerace) and average wheelchair speed of the fullmarathon group in wheelchair marathon racers with SCIs. Data analyzed by Spearman correlation analysis.
FIGURE 3. Relationship between plasma IL-6 levels immediately after the race (postrace) and average wheelchair speed in wheelchair marathon racers with SCIs.
DISCUSSION
The present study is the first to examine IL-6 response to wheelchair long distance race in SCI. The major findings of the present study were as follows: (1) IL-6 in both the halfand full-race groups increased after the race compared with stable values for TNF-a and hsCRP, (2) the magnitude of increase in IL-6 at 2 hours after the race was greater in the full-marathon group than the half-marathon, and (3) IL-6 and hsCRP before the race correlated negatively with average wheelchair speed in the full-group but not in the half-group. In AB persons, running, which involves several large muscles, is the mode of exercise associated with the most dramatic increase in plasma IL-6.12 Since contracting skeletal muscle per se is an important source of circulating IL-6 in the AB,21,22 it is not surprising that exercise involving a limited muscle mass in the AB, for example, muscles of the upper extremities, may be insufficient to increase plasma IL-6 above
298
| www.cjsportmed.com
pre-exercise level.23–25 However, the present study and 2-hour arm crank ergometer exercise in SCI14 as well as arm crank ergometer exercise in the AB14 demonstrated that exercise involving the upper arm muscle mass also increases plasma IL-6 above the pre-exercise level. Plasma IL-6 response is related to exercise intensity, duration, and the muscle mass involved in the contractile activity.12,13 Exercise intensity indirectly represents the muscle mass involved in the contractile activity.11 Therefore, the increase in plasma IL-6 level during the full- and half-wheelchair marathon race might be attributed to the sufficient intensity and duration of the exercise. The present results also suggest that bulk muscle mass of the upper extremities of athletes with SCI might compensate for the disadvantage. In the present study, the plasma IL-6 fold change immediately after the race relative to the prerace value was significantly higher in the full-group than the half-group, although wheelchair speed, that is, exercise intensity, was identical in the 2 groups. Indeed, the race time for the fullgroup was almost double than that for the half-group. These findings suggest that exercise duration could be more important than exercise intensity with respect to increases in plasma IL-6 levels during exercise. In fact, Fischer12 reported that exercise duration is the single most important factor determining the postexercise plasma IL-6 fold change in AB persons. Based on the 67 exercise trials in about 800 subjects, more than 50% of the variation in plasma IL-6 following exercise could be explained by exercise duration alone.12 The physiological stimulus of exercise duration for muscle-derived IL-6 in SCI should be similar to that in the AB. In most studies, TNF-a does not change during exercise.26 The present results of TNF-a in the full- and half-groups are in agreement with those of previous studies. Only highly strenuous, prolonged exercise, such as marathon running, results in a small increase in TNF-a plasma concentrations.17,18 Starkie et al18 investigated changes in plasma TNF-a and IL-6 in AB 2014 Lippincott Williams & Wilkins
Clin J Sport Med Volume 24, Number 4, July 2014
Cytokine Response to Wheelchair Marathon
TABLE 2. Blood Cell Counts and Leukocyte Subpopulations
Red blood cells, ·1012/L Half-group Full-group Hemoglobin, ·105/L Half-group Full-group Hematocrit, % Half-group Full-group Leukocytes, ·109/L Half-group Full-group Neutrophils, ·109/L Half-group Full-group Lymphocytes, ·109/L Half-group Full-group Monocytes, ·109/L Half-group Full-group
Prerace
Postrace
2 Hours Postrace
5.00 6 0.39 4.95 6 0.44
5.23 6 0.43 5.00 6 0.45
5.25 6 0.50 4.86 6 0.42
15.4 6 1.1 15.4 6 1.4
16.3 6 1.2 15.4 6 1.3
16.0 6 1.1 15.0 6 1.2
45.1 6 2.7 45.6 6 3.2
47.9 6 3.1 46.3 6 3.0
47.7 6 3.5 44.9 6 2.7
5.95 6 1.26 6.00 6 1.36
12.6 6 3.11* 15.3 6 3.25*
12.9 6 3.45* 14.8 6 3.33*
3.65 6 1.03 3.62 6 1.10
9.30 6 2.30* 12.7 6 3.02*
11.3 6 3.14 12.3 6 3.07*
1.78 6 0.55 1.91 6 0.57
2.72 6 1.27† 1.89 6 0.58
1.11 6 0.30 1.80 6 0.60
0.30 6 0.09 0.27 6 0.10
0.42 6 0.13 0.58 6 0.19*
0.47 6 0.20† 0.57 6 0.17*
Values are expressed as mean 6 SD. *P , 0.01, compared with prerace. †P , 0.05.
FIGURE 5. A, Correlation between plasma hsCRP levels before the race and average wheelchair speed of the full-marathon group of wheelchair marathon racers with SCIs. B, Correlation between plasma hsCRP levels before the race and plasma IL-6 levels of the full-marathon group of wheelchair marathon racers with SCIs. Data analyzed by Spearman correlation analysis.
subjects who participated in the Melbourne Marathon. In their study, plasma IL-6 and TNF-a concentrations were elevated after exercise and 2 hours after exercise, and the increase in the former was maintained at 24 hours after exercise. The results of the present study showed increases in plasma IL-6 after wheelchair full- and half-marathon race compared with stable TNF-a and hsCRP levels. Wheelchair full-marathon race is a very strenuous and high-intensity exercise; however, it is less strenuous compared with the full-marathon race in the AB. The stable levels of TNF-a and hsCRP suggest that both races were not extremely strenuous exercise for the participants with SCI. The reported rise in serum CK level in the AB after a full-marathon race was 26-fold;27 however, that in the present study was less than 2 to 3 times the baseline. Myoglobin increased immediately after the race and remained elevated until 2 hours after race. Myoglobin level was measured until 2 hours after the race in the present study, but we reported 2014 Lippincott Williams & Wilkins
previously that myoglobin increased immediately after the wheelchair full-marathon race and recovered at 24 hours after the race.28 It is possible that the increases in CK and myoglobin after the wheelchair race could be induced by increased sarcolemmal permeability rather than being a byproduct of muscle damage.29 In the present study, although the increase in myoglobin was still elevated 2 hours after the race, plasma IL-6 level recovered 2 hours after the race. Thus, we assumed that the response of plasma IL-6 in the present study is not associated with damage to the exercise muscles. It is well known that monocytes can produce IL-6 in inflammation state in AB persons. Several studies demonstrated that the expression level of IL-6 mRNA in monocytes, the blood mononuclear cells responsible for the increase in plasma IL-6 during sepsis, does not increase after exercise.30,31 Pedersen and Febbraio26 confirmed recently that monocytes are not the source of exercise-induced increase in plasma IL-6. In the present study, the number of plasma monocytes and plasma IL-6 level increased immediately after the fullmarathon race. Furthermore, plasma IL-6 concentration returned to the baseline level at 2 hours after the race, whereas monocyte count remained elevated until 2 hours after the race. Although the monocyte count in the half-group remained stable throughout the study, the mean plasma IL-6 concentration in this group increased immediately after the race. The results of our study are compatible with those of previous studies and strongly suggest that the source of increased plasma IL-6 during wheelchair marathon is not mainly due to monocytes. www.cjsportmed.com |
299
Clin J Sport Med Volume 24, Number 4, July 2014
Sasaki et al
TABLE 3. Concentrations of Plasma Catecholamine, Cortisol, Glucose, Insulin, CK, and Myoglobin
Adrenaline, nmol/L Half-group Full-group Noradrenaline, nmol/L Half-group Full-group Cortisol, nmol/L Half-group Full-group Glucose, mmol/L Half-group Full-group Insulin, mU/L Half-group Full-group CK, U/L Half-group Full-group Myoglobin, nmol/L Half-group Full-group
Prerace
Postrace
2 Hours Postrace
0.26 6 0.15 0.32 6 0.14
1.73 6 1.46* 1.52 6 1.24*
0.37 6 0.27 0.42 6 0.26
2.94 6 1.15 2.84 6 1.11
9.22 6 4.36* 6.79 6 2.34*
4.23 6 1.97 4.24 6 1.72
401 6 94 442 6 133
851 6 282* 701 6 288*
379 6 151 344 6 172
5.45 6 1.18 6.23 6 1.23
6.59 6 1.76 5.39 6 1.16
5.43 6 1.34 6.25 6 1.47
19.2 6 27.5 31.0 6 39.0
25.5 6 16.0 17.1 6 10.4
43.1 6 33.8 29.7 6 24.5
287 6 218 181 6 159
495 6 292† 320 6 201
258 6 122 439 6 276*
2.32 6 0.73 2.04 6 0.67
9.30 6 3.28† 15.6 6 11.4*
15.2 6 9.20* 21.2 6 15.5*
Values are expressed as mean 6 SD. *P , 0.01, compared with prerace. †P , 0.05.
The full-marathon group, but not the half-group, showed negative correlations between baseline plasma IL-6 and hsCRP levels with the average wheelchair speed. Fullmarathon athletes have to do hard training to complete the race. However, the half-marathon athletes can participate in the race without strenuous training. The wheelchair speed of the full-group, but not the half-group, correlates closely with the daily training. For this reason, IL-6 before the race correlated with wheelchair speed only in the full-marathon group. The results of the present study suggest that athletes who were free of any medical complications and had undergone adequate training for participation in the wheelchair fullmarathon race had low plasma IL-6 and hsCRP levels at rest. The present study has certain limitations. Recent studies described the effects of exercise on other anti-inflammatory cytokines, such as IL-1ra, IL-8, IL-10, and IL-15. However, we could not measure the levels of these anti-inflammatory cytokines in the present study. One reason was the importance of IL-6 as a muscle-derived cytokine. Another reason was that we were not allowed to collect a large quantity of blood samples from the subjects, for fear of the ethics committee that such intervention could be an infringement to the race participation or influence the race outcome at the 28th Oita International Wheelchair Marathon Race. For this reason, the present study examined only changes in IL-6 as a representative anti-inflammatory cytokine. Further studies are needed to explore other muscle-derived interleukins.
CONCLUSIONS In the present study, red blood cell count, hemoglobin, and hematocrit remained unchanged throughout the race. The results suggest that dehydration did not occur during the race, a factor that may depend on whether subjects are allowed to eat and drink freely before and during the race. Therefore, there is no effect for hemoconcentration on our data throughout the race. During resting conditions, IL-6 is not produced by skeletal muscles32 and 10% to 35% of the body IL-6 is produced by adipose tissues.33 Due to the high plasma IL-6 levels at rest in some patients with metabolic diseases, this cytokine is considered to be involved in chronic diseases and a proinflammatory cytokine that promotes insulin resistance and hyperlipidemia.26 However, Pedersen and Febbraio26 proposed that the high level of IL-6 at rest could represent a “defense” mechanism against the proinflammatory actions of TNF-a. In 84 healthy AB persons, Fischer et al34 investigated whether the basal levels of IL-6 and C-reactive protein (CRP) reflect the degree of regular physical activity compared with other markers of inflammation associated with lifestylerelated morbidity. They demonstrated that low levels of IL-6 and CRP, but not TNF-a, reflect regular physical activity. Therefore, we speculate that the low levels of IL-6 before the race reflect the health status in SCI. However, the plasma level of IL-6 in the full-group was similar to that of the halfgroup at baseline (before the race). Considered together, these findings suggest that plasma IL-6 was at low levels before the race even in the half-marathon group.
300
| www.cjsportmed.com
The present study demonstrated that upper arm wheelchair marathon induced increases in plasma IL-6 but had no effect on TNF-a and hsCRP. Furthermore, before the race, the top athletes of the full-marathon group had low plasma IL-6 and hsCRP levels. Our results suggest that wheelchair marathon race, especially the full marathon, and daily training might have beneficial effects on athletes with SCI through the plasma IL-6 response. It is anticipated that sports activities that induce IL-6 response help prevent heart diseases and type 2 diabetes even in SCI persons. We recommend that SCI individuals participate in various sports activities.
ACKNOWLEDGMENTS The authors thank Drs Masaki Goto, Motohiko Banno, and Tomoyuki Ito for the clinical assistance. They also thank Dr Faiq G. Issa for the careful reading and editing of the manuscript. REFERENCES 1. Post MW, van Asbeck FW, van Dijk AJ, et al. Services for spinal cord injured: availability and satisfaction. Spinal Cord. 1997;35:109–115. 2. Buchholz AC, Pencharz PB. Energy expenditure in chronic spinal cord injury. Curr Opin Clin Nutr Metab Care. 2004;7:635–639. 3. Shiba S, Okawa H, Uenishi H, et al. Longitudinal changes in physical capacity over 20 years in athletes with spinal cord injury. Arch Phys Med Rehabil. 2010;91:1262–1266. 4. Bauman WA, Spungen AM. Coronary heart disease in individuals with spinal cord injury: assessment of risk factors. Spinal Cord. 2008;46:466– 476.
2014 Lippincott Williams & Wilkins
Clin J Sport Med Volume 24, Number 4, July 2014 5. Pedersen BK, Akerström TC, Nielsen AR, et al. Role of myokines in exercise and metabolism. J Appl Physiol. 2007;103:1093–1098. 6. Fiers W. Tumor necrosis factor. Characterization at the molecular, cellular and in vivo level. FEBS Lett. 1991;285:199–212. 7. Matthys P, Mitera T, Heremans H, et al. Anti-gamma interferon and antiinterleukin-6 antibodies affect staphylococcal enterotoxin B-induced weight loss, hypoglycemia, cytokine release in D-galactosamine-sensitized and unsensitized mice. Infect Immun. 1995;63:1158–1164. 8. Mizuhara H, O’Neill E, Seki N, et al. T cell activation-associated hepatic injury: mediation by tumor necrosis factors and protection by interleukin6. J Exp Med. 1994;179:1529–1537. 9. Starkie R, Ostrowski SR, Jauffred S, et al. Exercise and IL-6 infusion inhibit endotoxin-induced TNF-alpha production in humans. FASEB J. 2003;17:884–886. 10. Choy EH, Isenberg DA, Garrood T, et al. Therapeutic benefit of blocking interleukin-6 activity with an anti-interleukin-6 receptor monoclonal antibody in rheumatoid arthritis: a randomized, double-blind, placebo-controlled, dose-escalation trial. Arthritis Rheum. 2002;46:3143–3150. 11. Nishimoto N, Yoshizaki K, Miyasaka N, et al. Treatment of rheumatoid arthritis with humanized anti-interleukin-6 receptor antibody: a multicenter, double-blind, placebo-controlled trial. Arthritis Rheum. 2004;50: 1761–1769. 12. Fischer CP. Interleukin-6 in acute exercise and training: what is the biological relevance? Exerc Immunol Rev. 2006;12:6–33. 13. Ostrowski K, Schjerling P, Pedersen BK. Physical activity and plasma interleukin-6 in humans: effect of intensity of exercise. Eur J Appl Physiol. 2000;83:512–515. 14. Umemoto Y, Furusawa K, Kouda K, et al. Plasma IL-6 levels during arm exercise in persons with spinal cord injury. Spinal Cord. 2011;49:1182– 1187. 15. Kouda K, Furusawa K, Sugiyama H, et al. Does 20-min arm crank ergometer exercise increase plasma interleukin-6 in individuals with cervical spinal cord injury? Eur J Appl Physiol. 2012;112:597–604. 16. Furusawa K, Tajima F, Tanaka Y, et al. Short-term attenuation of natural killer cell cytotoxic activity in wheelchair marathoners with paraplegia. Arch Phys Med Rehabil. 1998;79:1116–1121. 17. Bruunsgaard H, Hartkopp A, Mohr T, et al. In vivo cell-mediated immunity and vaccination response following prolonged, intense exercise. Med Sci Sports Exerc. 1997;29:1176–1181. 18. Starkie RL, Rolland J, Angus DJ, et al. Circulating monocytes are not the source of elevations in plasma IL-6 and TNF-alpha levels after prolonged running. Am J Physiol Cell Physiol. 2001;280:769–774. 19. Hunter LW, Rorie DK, Yaksh TL, et al. Concurrent separation of catecholamines, dihydroxyphenylglycol, vasoactive intestinal peptide, and
2014 Lippincott Williams & Wilkins
Cytokine Response to Wheelchair Marathon
20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34.
neuropeptide Y in superfusate and tissue extract. Anal Biochem. 1988; 173:340–352. Ostrowski K, Rohde T, Asp S, et al. Pro- and anti-inflammatory cytokine balance in strenuous exercise in humans. J Physiol. 1999;515:287–291. Fischer CP, Hiscock NJ, Penkowa M, et al. Supplementation with vitamins C and E inhibits the release of interleukin-6 from contracting human skeletal muscle. J Physiol. 2004;558:633–645. Steensberg A, van Hall G, Osada T, et al. Production of interleukin-6 in contracting human skeletal muscles can account for the exercise-induced increase in plasma interleukin-6. J Physiol. 2000;529:237–242. Bergfors M, Barnekow-Bergkvist M, Kalezic N, et al. Short-term effects of repetitive arm work and dynamic exercise on glucose metabolism and insulin sensitivity. Acta Physiol Scand. 2005;183:345–356. Hirose L, Nosaka K, Newton M, et al. Changes in inflammatory mediators following eccentric exercise of the elbow flexors. Exerc Immunol Rev. 2004;10:75–90. Nosaka K, Clarkson PM. Changes in indicators of inflammation after eccentric exercise of the elbow flexors. Med Sci Sports Exerc. 1996;28: 953–961. Pedersen BK, Febbraio MA. Muscle as an endocrine organ: focus on muscle-derived interleukin-6. Physiol Rev. 2008;88:1379–1406. Siegel AJ, Silverman LM, Holman BL. Elevated creatine kinase MB isoenzyme levels in marathon runners. Normal myocardial scintigrams suggest noncardiac source. JAMA. 1981;246:2049–2051. Ide M, Tajima F, Furusawa K, et al. Wheelchair marathon racing causes striated muscle distress in individuals with spinal cord injury. Arch Phys Med Rehabil. 1999;80:324–327. Kuipers H. Exercise-induced muscle damage. Int J Sports Med. 1994;15: 132–135. Ullum H, Haahr PM, Diamant M, et al. Bicycle exercise enhances plasma IL-6 but does not change IL-1 alpha, IL-1 beta, IL-6, or TNF-alpha premRNA in BMNC. J Appl Physiol. 1994;77:93–97. Moldoveanu AI, Shephard RJ, Shek PN. Exercise elevates plasma levels but not gene expression of IL-1beta, IL-6, TNF-alpha in blood mononuclear cells. J Appl Physiol. 2000;89:1499–1504. Hiscock N, Chan MH, Bisucci T, et al. Skeletal myocytes are a source of interleukin-6 mRNA expression and protein release during contraction: evidence of fiber type specificity. FASEB J. 2004;18:992–994. Mohamed-Ali V, Goodrick S, Rawesh A, et al. Subcutaneous adipose tissue releases interleukin-6, but not tumor necrosis factor-alpha, in vivo. J Clin Endocrinol Metab. 1997;82:4196–4200. Fischer CP, Berntsen A, Perstrup LB, et al. Plasma levels of interleukin-6 and C-reactive protein are associated with physical inactivity independent of obesity. Scand J Med Sci Sports. 2007;17:580–587.
www.cjsportmed.com |
301
