Relationship Between Serum Paraoxonase and Homocysteine Thiolactonase Activity, Adipokines, and Asymmetric Dimethyl Arginine Concentrations in Renal Transplant Patients L. Locsey, I. Seres, F. Sztanek, M. Harangi, J. Padra, D. Kovacs, R. Fedor, L. Asztalos, and G. Paragh ABSTRACT Paraoxonase lactonase activity protects against homocysteinylation; therefore, it can be a potential contributing factor to prevent atherosclerosis. We aimed to determine paraoxonase and HTLase activities and to clarify the relationship between HTLase activity and some cardiovascular risk factors, such as homocysteine, cystatin C asymmetric dimethylarginine (ADMA), and adipokines both in hemo dialyzed and transplanted patients. Among 114 hemodialyzed, 80 transplanted and 64 healthy control subjects, we investigated body mass index (BMI) as well as fasting serum contents of urea, uric acid, creatinine, cystatin C, homocysteine, glucose, lipids, total protein and albumin. Serum paraoxonase (PON 1) and HTLase activities were measured spectrophotometrically. ADMA, ADPN adiponectin, leptin (LEP) levels was determined with a sandwich enzyme-linked immunosorbent assay method. Dyslipidemic patients showed hypercholesterolemia, and high low-density lipoprotein (LDL); parallel with improved renal function, they displayed decreased cystatin C and homocysteine levels (P < .001). There was a significant negative correlation between PON 1 activity and cystatin C and homocysteine concentrations (P < .05). Obese patients revealed significantly higher LDL (P < .05) and leptin concentrations (P < .01). There was a significant positive correlation between PON 1 activity and adiponectin levels (P ¼ .0276). Both dialyzed and transplanted patients displayed significantly lower HTLase activities compared to the control group (P < .001), particularly lower HTLase and PON 1 activities in dialyzed subjects compared with the transplanted group (P < .05). HTLase activity showed significant negative correlations with ADMA levels among the whole study population (P < .001), whereas positive associations were noted between PON 1 and HTLase activities (P < .001). HTLase activity may be a new predictor of cardiovascular risk in renal failure although it is modulated by other risk factors.
I
NFLAMMATION AND ELEVATED OXIDATIVE STRESS are associated with atherosclerotic coronary artery disease among chronic kidney disease patients. Highdensity lipoprotein (HDL)-associated human paraoxonase-1 (PON 1) blocks oxidation of low-density lipoproteins (LDL) protecting against the development of atherosclerosis.1e5 The serum PON 1 enzyme also has lactonase activity, that protects proteins against homocysteinylation by detoxifying Hcythiolactone.6e9 PATIENTS AND METHODS Eighty kidney transplant recipients of mean age 46.3 8.7 years, 114 chronic hemodialysis patients of 53.6 12.4 years and 64 healthy controls of 51.5 9.63 years were included in the present
study. According to their body mass index (BMI), we divided them into groups, separating malnourished (BMI < 20 kg/m2) from obese (BMI > 30 kg/m2) individuals. There were 14 obese and 10 malnourished patients in the transplanted group and 39 and 25 respectively on hemodialysis.
From the Institute of Surgery, (L.L., D.K., R.F., L.A.) and 1st Department of Internal Medicine (I.S., F.S., M.H., J.P., G.P.), University of Debrecen Medical and Health Science Center, Debrecen, Hungary. Address reprint requests to Lajos Locsey, MD, Institute of Surgery, University of Debrecen Medical and Health Science Center, Móricz Zs Str 22,4004 Debrecen, Hungary. E-mail: [email protected]
ª 2013 by Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010-1710
0041-1345/13/$esee front matter http://dx.doi.org/10.1016/j.transproceed.2013.10.003
Transplantation Proceedings, 45, 3685e3687 (2013)
3685
3686
LOCSEY, SERES, SZTANEK ET AL
Fasting plasma total Hcy concentrations were determined by enzyme-linked immunoassay (ELISA). Plasma cystatin C measurements were performed using a latex-enhanced reagent. Serum cholesterol and triglyceride levels were measured using enzymatic and colorimetric tests, while HDL cholesterol (HDL-C), by homogenous, enzymatic, colorimetric assay as was LDL cholesterol (LDL-C). PON 1 paraoxonase activity was estimated using a paraoxon (O,O-diethyl-O-p-nitrophenylphosphate) substrate, with generation of 4-nitrophenol measured spectrophotometrically. Commercially available assay kits were used for PON 1 lactonase activity (Alfresa Auto HTLase; Alfresa Pharma Corporation, Japan), serum as well as asymmetric dimethylarginine (ADMA), total adiponectin and leptin concentrations in hemodialyzed patients were measured with commercially available ELISA kits.6e10
RESULTS
High total cholesterol levels (5.35 1.22 mmol/L) and LDL-C levels (2.89 0.92 mmol/L) were observed in renal transplant patients Serum cystatin C and homocysteine levels were significantly greater higher in renal transplant compared with hemodialyzed patients (P < .001). Laboratory parameters of the two groups are summarized in Table 1. The LDL-C concentrations (P < .05) and leptin levels (P < .01) were significantly higher among obese versus malnourished transplant patients. Serum adiponectin levels (16.61 vs 23.69 mg/mL) and PON 1 activities (99.18 vs 79.59 U/L) but not serum leptin concentrations and PON 1 activities were significantly different between obese and malnourished renal transplant recipients. PON 1 activities showed a positive relationship with adiponectin
levels (r ¼ 0.4493, P ¼ .0276), and a negative correlation with cystatin C levels and homocysteine concentrations in both patient groups (r ¼ 0.37, P < .05). There were significantly higher C-reactive protein (CRP) and ADMA levels in malnourished hemodialyzed compared with obese subjects (P < .001). Hemodialyzed and renal transplant patients displayed significantly lower lactonase and PON 1 activities compared to controls (P < .001). The haemodialyzed group displayed significantly lower PON 1 paraoxonase and lactonase activities compared with transplanted patients (P < .05). Among the whole study population a significant negative correlation was observed between lactonase activities and ADMA levels (r ¼ 0.4412, P < .001) and a significant positive correlation, with PON 1 paraoxonase activity (r ¼ 0.5163, P < .001). The inverse relationship between PON 1 paraoxonase activities and ADMA levels among the whole population was not significant (P ¼ .2302). Lactonase activity revealed a positive correlation with PON/HDL ratios among malnourished patients (P < .03). PON 1 paraoxonase and lactonase activities increased in parallel with improved renal function.
DISCUSSION
Our findings demonstrated decreases in PON 1 paraoxonase and lactonase activities with elevated CRP and ADMA levels, an may reflect observation that contributions to accelerated atherosclerosis among obese renal patients. PON 1 paraoxonase and lactonase activities may proffer new predictors of cardiovascular risk in chronic kidney disease.
Table 1. Laboratory Parameters of Dialyzed and Transplanted Patients HD
Age (y) BMI (kg/m2) Cholesterol (mmol/L) Triglyceride (mmol/L) LDL CHO (mmol/L) HDL CHO (mmol/L) Glucose (mmol/L) Albumin (g/L) Cystatin C (mg/L) Homocysteine (mmol/L) Creatinine (mmol/L) hsCRP (mg/L) ADMA (ng/mL) PON activity (U/L) Log PON activity (U/L) PON activity HDL Leptin (ug/mL) Adiponectin (ng/mL) HTLase activity (U/L) Log HTLase activity (U/L) Arylesterase activity (U/L)
65.75 27.35 5.11 2.05 2.88 1.17 6.82 39.8 4.19 21.65 661 9.78 273.3 58.0 1.68 54.1 30.87 16.45 123.0 2.04 103.7
(10.36)a (6.14)a (1.99)b (1.21)a (0.95) (0.28)a (2.70)a (9.6)a (2.31)a (7.18)a (222)a (7.31)a (74.2)a (36.7)a (0.27)a (39.3)b (16.89) (6.14) (57.8)a (0.21) (12.8)a
TRx
51.01 26.49 5.35 2.41 2.89 1.63 5.63 42.2 2.15 16.78 145 3.80 230.9 81.0 1.83 59.2 36.87 16.11 146.3 2.11 96.3
(10.25)a (4.98)a (1.22)b (1.73)a (0.92) (0.85) (1.87)a (8.5)a (0.87)a (8.29)b (68)a (3.20)a (52.5)a (46.5)a (0.26)a (45.9)c (14.67) (4.53) (69.9)a (0.22)a (16.2)
CONTROLS
49.29 22.43 4.72 0.92 2.56 1.77 4.51 45.9 1.01 9.91 67.5 1.86 152.8 137.0 2.06 79.8 35.19 17.29 242.0 2.34 90.40
(9.97) (2.19) (0.78) (0.68) (0.76) (0.48) (0.53) (3.9) (0.11) (2.17) (14.6) (2.20) (60.6) (82.1) (0.26) (48.2) (12.78) (5.1) (104) (0.21) (20.70)
P (TRx vs HD)
I
NFLAMMATION AND ELEVATED OXIDATIVE STRESS are associated with atherosclerotic coronary artery disease among chronic kidney disease patients. Highdensity lipoprotein (HDL)-associated human paraoxonase-1 (PON 1) blocks oxidation of low-density lipoproteins (LDL) protecting against the development of atherosclerosis.1e5 The serum PON 1 enzyme also has lactonase activity, that protects proteins against homocysteinylation by detoxifying Hcythiolactone.6e9 PATIENTS AND METHODS Eighty kidney transplant recipients of mean age 46.3 8.7 years, 114 chronic hemodialysis patients of 53.6 12.4 years and 64 healthy controls of 51.5 9.63 years were included in the present
study. According to their body mass index (BMI), we divided them into groups, separating malnourished (BMI < 20 kg/m2) from obese (BMI > 30 kg/m2) individuals. There were 14 obese and 10 malnourished patients in the transplanted group and 39 and 25 respectively on hemodialysis.
From the Institute of Surgery, (L.L., D.K., R.F., L.A.) and 1st Department of Internal Medicine (I.S., F.S., M.H., J.P., G.P.), University of Debrecen Medical and Health Science Center, Debrecen, Hungary. Address reprint requests to Lajos Locsey, MD, Institute of Surgery, University of Debrecen Medical and Health Science Center, Móricz Zs Str 22,4004 Debrecen, Hungary. E-mail: [email protected]
ª 2013 by Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010-1710
0041-1345/13/$esee front matter http://dx.doi.org/10.1016/j.transproceed.2013.10.003
Transplantation Proceedings, 45, 3685e3687 (2013)
3685
3686
LOCSEY, SERES, SZTANEK ET AL
Fasting plasma total Hcy concentrations were determined by enzyme-linked immunoassay (ELISA). Plasma cystatin C measurements were performed using a latex-enhanced reagent. Serum cholesterol and triglyceride levels were measured using enzymatic and colorimetric tests, while HDL cholesterol (HDL-C), by homogenous, enzymatic, colorimetric assay as was LDL cholesterol (LDL-C). PON 1 paraoxonase activity was estimated using a paraoxon (O,O-diethyl-O-p-nitrophenylphosphate) substrate, with generation of 4-nitrophenol measured spectrophotometrically. Commercially available assay kits were used for PON 1 lactonase activity (Alfresa Auto HTLase; Alfresa Pharma Corporation, Japan), serum as well as asymmetric dimethylarginine (ADMA), total adiponectin and leptin concentrations in hemodialyzed patients were measured with commercially available ELISA kits.6e10
RESULTS
High total cholesterol levels (5.35 1.22 mmol/L) and LDL-C levels (2.89 0.92 mmol/L) were observed in renal transplant patients Serum cystatin C and homocysteine levels were significantly greater higher in renal transplant compared with hemodialyzed patients (P < .001). Laboratory parameters of the two groups are summarized in Table 1. The LDL-C concentrations (P < .05) and leptin levels (P < .01) were significantly higher among obese versus malnourished transplant patients. Serum adiponectin levels (16.61 vs 23.69 mg/mL) and PON 1 activities (99.18 vs 79.59 U/L) but not serum leptin concentrations and PON 1 activities were significantly different between obese and malnourished renal transplant recipients. PON 1 activities showed a positive relationship with adiponectin
levels (r ¼ 0.4493, P ¼ .0276), and a negative correlation with cystatin C levels and homocysteine concentrations in both patient groups (r ¼ 0.37, P < .05). There were significantly higher C-reactive protein (CRP) and ADMA levels in malnourished hemodialyzed compared with obese subjects (P < .001). Hemodialyzed and renal transplant patients displayed significantly lower lactonase and PON 1 activities compared to controls (P < .001). The haemodialyzed group displayed significantly lower PON 1 paraoxonase and lactonase activities compared with transplanted patients (P < .05). Among the whole study population a significant negative correlation was observed between lactonase activities and ADMA levels (r ¼ 0.4412, P < .001) and a significant positive correlation, with PON 1 paraoxonase activity (r ¼ 0.5163, P < .001). The inverse relationship between PON 1 paraoxonase activities and ADMA levels among the whole population was not significant (P ¼ .2302). Lactonase activity revealed a positive correlation with PON/HDL ratios among malnourished patients (P < .03). PON 1 paraoxonase and lactonase activities increased in parallel with improved renal function.
DISCUSSION
Our findings demonstrated decreases in PON 1 paraoxonase and lactonase activities with elevated CRP and ADMA levels, an may reflect observation that contributions to accelerated atherosclerosis among obese renal patients. PON 1 paraoxonase and lactonase activities may proffer new predictors of cardiovascular risk in chronic kidney disease.
Table 1. Laboratory Parameters of Dialyzed and Transplanted Patients HD
Age (y) BMI (kg/m2) Cholesterol (mmol/L) Triglyceride (mmol/L) LDL CHO (mmol/L) HDL CHO (mmol/L) Glucose (mmol/L) Albumin (g/L) Cystatin C (mg/L) Homocysteine (mmol/L) Creatinine (mmol/L) hsCRP (mg/L) ADMA (ng/mL) PON activity (U/L) Log PON activity (U/L) PON activity HDL Leptin (ug/mL) Adiponectin (ng/mL) HTLase activity (U/L) Log HTLase activity (U/L) Arylesterase activity (U/L)
65.75 27.35 5.11 2.05 2.88 1.17 6.82 39.8 4.19 21.65 661 9.78 273.3 58.0 1.68 54.1 30.87 16.45 123.0 2.04 103.7
(10.36)a (6.14)a (1.99)b (1.21)a (0.95) (0.28)a (2.70)a (9.6)a (2.31)a (7.18)a (222)a (7.31)a (74.2)a (36.7)a (0.27)a (39.3)b (16.89) (6.14) (57.8)a (0.21) (12.8)a
TRx
51.01 26.49 5.35 2.41 2.89 1.63 5.63 42.2 2.15 16.78 145 3.80 230.9 81.0 1.83 59.2 36.87 16.11 146.3 2.11 96.3
(10.25)a (4.98)a (1.22)b (1.73)a (0.92) (0.85) (1.87)a (8.5)a (0.87)a (8.29)b (68)a (3.20)a (52.5)a (46.5)a (0.26)a (45.9)c (14.67) (4.53) (69.9)a (0.22)a (16.2)
CONTROLS
49.29 22.43 4.72 0.92 2.56 1.77 4.51 45.9 1.01 9.91 67.5 1.86 152.8 137.0 2.06 79.8 35.19 17.29 242.0 2.34 90.40
(9.97) (2.19) (0.78) (0.68) (0.76) (0.48) (0.53) (3.9) (0.11) (2.17) (14.6) (2.20) (60.6) (82.1) (0.26) (48.2) (12.78) (5.1) (104) (0.21) (20.70)
P (TRx vs HD)
