Arch Gynecol Obstet DOI 10.1007/s00404-014-3490-3
GYNECOLOGIC ENDOCRINOLOGY AND REPRODUCTIVE MEDICINE
Serum levels of fetuin A are increased in women with gestational diabetes mellitus Ozlem Turhan Iyidir • Ceyla Konca Degertekin • Banu Aktas Yilmaz • Alev E. Altinova • Fusun B. Toruner Nuray Bozkurt • Goksun Ayvaz • Mujde Akturk
•
Received: 30 May 2014 / Accepted: 22 September 2014 Ó Springer-Verlag Berlin Heidelberg 2014
Abstract Purpose Fetuin A is associated with insulin resistance and type 2 diabetes mellitus (DM). We aimed to investigate circulating fetuin A concentrations in gestational diabetes mellitus (GDM). Methods Serum fetuin A levels were studied in 26 pregnant women with GDM and 24 healthy pregnant women between 24th and 28th gestational weeks. Fetuin A levels were also evaluated in 18 of women with GDM at postpartum. Results Fetuin A concentrations were significantly increased in women with GDM compared to healthy pregnant women (35.0 ± 3.2 vs. 32.0 ± 4.4 ng/ml; p = 0.01). Also, fetuin A levels in women with GDM significantly decreased at postpartum period (35.0 ± 3.2 vs. 31.7 ± 3.9 ng/ml; p = 0.001). In whole pregnant women, there were positive correlations between fetuin A and HbA1c (r = 0.418, p = 0.002), total cholesterol (r = 0.332, p = 0.018) and triglycerides (r = 0.306, p = 0.031). Multivariate regression analysis demonstrated that HbA1c was the important predictor of circulating fetuin A level (beta = 0.375, p = 0.01). Conclusion In conclusion, our results indicate that serum fetuin A concentrations are increased in women with GDM and decreased after delivery.
O. T. Iyidir (&) C. K. Degertekin B. A. Yilmaz A. E. Altinova F. B. Toruner G. Ayvaz M. Akturk Department of Endocrinology and Metabolism, Gazi University Faculty of Medicine, Ankara, Turkey e-mail: [email protected] N. Bozkurt Department of Obstetrics and Gynecology, Gazi University Faculty of Medicine, Ankara, Turkey
Therefore, fetuin A might have a role in the development of insulin resistance and the metabolic changes in GDM. Keywords Gestational diabetes mellitus Fetuin A Lipids HbA1c
Introduction Fetuin A which is also known as a2-HS-glycoprotein (AHSG) is a multifunctional glycoprotein, mainly synthesized in the liver [1]. It has several roles particularly on vascular calcification and bone metabolism [2]. Crosssectional studies have demonstrated that high fetuin A concentrations are associated with insulin resistance [3], polycystic ovary syndrome [4] and type 2 diabetes mellitus (DM) [5–7]. Moreover, a prospective study revealed that plasma fetuin A is related to an increased risk for the development of DM in women [8]. Regarding this relationship between fetuin A and insulin resistance, a direct inhibitory effect of fetuin A has been shown on insulin receptor autophosphorylation in skeletal muscle and hepatocytes [9]. Gestational diabetes mellitus (GDM) develops when there is an impairment of the compensatory increase in insulin secretion from the beta cells to overcome insulin resistance seen in pregnancy [10]. GDM and type 2 DM have similar pathogenetic mechanisms as well as genetic factors and the women with previous GDM have increased risk of type 2 DM [11, 12]. Although the exact mechanisms related to the insulin resistance seen in GDM are not fully known, decreased tyrosine phosphorylation of insulin receptor and insulin receptor substrate 1 have been shown in GDM [13].
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Taking the negative effect of fetuin A on tyrosine kinase signaling into account, one can suggest that fetuin A may play a role in the development of insulin resistance in GDM. However, there are limited studies investigating fetuin A levels in women with GDM. Kalabay et al. showed increased levels of fetuin A in women with GDM compared with healthy pregnant women [14]. In contrast to this study, no difference was found in fetuin A levels during OGTT at third trimester of the pregnancy and postpartum period between women with GDM and healthy pregnant controls [15]. Therefore, we aimed to assess whether circulating fetuin A concentrations are altered and related to the metabolic changes in women with GDM.
Materials and methods We analyzed the data of 26 pregnant women with GDM and 24 age and body mass index (BMI)-matched women with healthy pregnancies as controls. All pregnant women included in this study were screened for GDM using a 50-g glucose challenge test (GCT). Women with a 1-h glucose level of 140 mg/dl or more proceeded to 100-g oral glucose tolerance test (OGTT) using Carpenter and Coustan guidelines [16]. Women with two or more abnormal values were diagnosed as having GDM. None of the pregnant women included in this study had preeclampsia, eclampsia, pregnancy-induced hypertension or history of hypertension before pregnancy. None of the patients had history of alcohol before pregnancy. Thirteen women with GDM (50.0 %) were treated with insulin therapy in addition to diet during pregnancy. The study protocol was approved by
the local Ethics Committee. All patients gave written informed consent before taking part in the study. Fasting blood samples were obtained from all participants between 24th and 28th gestational weeks. Eighteen of 26 patients with GDM were reevaluated after 3 months postpartum. Blood samples were centrifuged and stored at -80 °C until being studied. The lipid parameters (total cholesterol, HDL cholesterol and triglycerides) were measured by standardized methods using autoanalysers. LDL cholesterol levels were calculated according to the formula described by Friedewald et al. [17]. Glycosylated hemoglobin (HbA1c) levels were determined using Agilent Technologies 1200 Series analyzer with commercially available kits by HPLC method (Chromsystems Instruments and Chemicals GmbH. Mu¨nchen, Germany). Serum fetuin A was measured with enzyme-linked immunosorbent assay (ELISA) according to the manufacturer’s instructions (Bio Vendor Laboratory Medicine Inc. Brno, Czech Republic). Serum high-sensitive C-reactive protein (hs-CRP) was determined using a commercially available sandwich ELISA kit (DRG International, USA). Statistical analysis Statistical analyses were performed using the SPSS software version 16. Continuous data were presented as mean ± standard deviation or medians (minimum–maximum) as appropriate. The level of significance was determined using the t test for normally distributed values and the Mann–Whitney U test was used for non-normally distributed values. Paired t test was used for comparison
Table 1 Characteristics of women with GDM in pregnancy and postpartum and healthy pregnant controls
Age (years) 2
GDM (n = 26)
Postpartum GDM (n = 18)
Pregnant controls (n = 24)
31.3 ± 5.3
30.6 ± 4.7
29.6 ± 5.4
p1 0.274
p2 –
BMI (kg/m )
29.1 ± 5.2
27.1 ± 5.4
27.5 ± 3.6
0.217
\0.001
Fasting blood glucose (mg/dl)
86.5 (72.0–106.0)
92.0 (73.0–111.0)
77.0 (68.0–81.0)
\0.001
0.104
HbA1c (%)
5.4 (5.0–6.4)
5.2 (4.8–6.0)
5.0 (4.5–5.6)
\0.001
0.171
Total cholesterol (mg/dl) LDL cholesterol (mg/dl)
259.3 ± 51.8 147.0 ± 51.7
204.1 ± 30.0 127.9 ± 30.4
233.5 ± 56.6 130.6 ± 40.1
0.099 0.251
\0.001 0.198
HDL cholesterol (mg/dl)
60.5 ± 14.6
54.1 ± 13.0
61.6 ± 14.6
0.802
0.025 \0.001
Triglycerides (mg/dl)
248.7 ± 93.8
114.3 ± 51.0
203.7 ± 72.4
0.065
Hs-CRP (mg/l)
4.4 ± 2.6
2.5 ± 2.1
4.3 ± 2.4
0.936
0.006
Fetuin-A (ng/ml)
35.0 ± 3.2
31.7 ± 3.9
32.0 ± 4.4
0.01
0.001
Data were given as mean ± SD or median (minimum–maximum) GDM gestational diabetes mellitus, BMI body mass index, LDL low-density lipoprotein, HDL high-density lipoprotein, hs-CRP high-sensitive C-reactive protein 1 p GDM vs. pregnant controls 2
p GDM vs. postpartum GDM
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within GDM group before and after delivery. Correlation analyses were performed using Pearson’s coefficients. Spearman’s test was used when necessary. p value of\0.05 was considered statistically significant.
cholesterol and triglycerides as independent variables revealed that HbA1c was the important predictor of circulating fetuin A levels (r2 = 0.266, beta = 0.375, p = 0.01).
Results
Discussion
Table 1 shows the characteristics of women with GDM in pregnancy and postpartum and healthy pregnant controls. There was no significant difference in terms of age, gestational age and BMI between GDM and control group (p [ 0.05). When compared to control group, women with GDM had high levels of fasting blood glucose (88.3 ± 10.3 vs. 75.7 ± 3.4 mg/dl; p \ 0.001) and HbA1c (5.4 ± 0.3 vs. 5.0 ± 0.2 %; p \ 0.001). GDM and control group were similar in terms of total cholesterol (259.3 ± 51.8 vs. 233.5 ± 56.6 mg/dl; p = 0.099), LDL cholesterol (147.0 ± 51.7 vs. 130.6 ± 40.1 mg/dl; p = 0.251), HDL cholesterol (60.5 ± 14.6 vs. 61.6 ± 14.6 mg/dl; p = 0.802) and triglycerides (248.7 ± 93.8 vs. 203.7 ± 72.4 mg/dl; p = 0.065). There was also no significant difference in hs-CRP levels between GDM and control group (4.4 ± 2.6 vs. 4.3 ± 2.4 mg/l; p = 0.936). Serum fetuin A levels were found to be significantly increased compared to control group (35.0 ± 3.2 vs. 32.0 ± 4.4 ng/ml; p = 0.01). In 18 postpartum women with GDM, 13 (72.2 %) patients had normal glucose tolerance, 4 (22.2 %) had impaired fasting glucose and 1 (5.6 %) had impaired glucose tolerance. Serum fetuin A concentrations in women with GDM significantly decreased at postpartum period (35.0 ± 3.2 vs. 31.7 ± 3.9 ng/ml; p = 0.001). In whole pregnant women, there were positive correlations between fetuin A and HbA1c (r = 0.418, p = 0.002) (Fig. 1), total cholesterol (r = 0.332, p = 0.018) and triglycerides (r = 0.306, p = 0.031). Multivariate linear regression analysis including fetuin A as dependent variable and age, BMI, HbA1c, total
Our results showed that serum fetuin A levels are significantly increased in patients with GDM as compared with healthy pregnant controls and decreased after delivery. These findings imply that circulating fetuin A may contribute to the pathogenesis of the GDM possibly through tyrosine phosphorylation. The present study is in accordance with one of the previous studies reporting elevated serum fetuin A (AHSG) levels in women with GDM in the 20–40th gestational weeks compared to healthy pregnant women during all trimesters of pregnancy and non-pregnant controls [14]. Kalabay et al. [14] also showed that fetuin A levels were increased in pregnancy and positive correlations between fetuin A and measurable parameters of insulin resistance such as C-peptide and C-peptide/blood glucose ratio, as well. Therefore, our results confirm an earlier study by Kalabay et al. [14]. But, they did not evaluate the women with GDM at postpartum period. The other previous study reported that maternal fasting fetuin A and fetuin A after 75 gr glucose load did not differ between pregnant women with and without GDM at 28th week of gestation as well as 3 months after delivery [15]. The lack of alteration in fetuin A levels in that study may be related to their study size because their patient number was relatively low. Fetuin A expression has been shown in the placenta [18]. Moreover, high level of fetuin A was identified in fetal life [19]. Maternal and fetal fetuin A levels were found to be similar and correlated with each other in normal pregnancy suggesting transplacental transfer [20]. However, there is not any data about the importance of the increased fetuin A in terms of fetuses of women with GDM. Future studies are needed to clarify this question. Regarding the relationship between fetuin A and type 2 DM, a community-based study revealed increased fetuin A concentrations are associated with insulin resistance and type 2 DM in middle-aged and elderly Chinese [7]. Although most of the studies demonstrated high levels of fetuin A in patients with type 2 DM [5, 6], a previous study reported significantly lower serum fetuin A concentrations in type 2 DM than controls [21]. Moreover, similar fetuin A levels have been shown between type 2 DM and nondiabetic subjects in another study [22] The reason of these contrast results related to fetuin A concentrations in type 2 DM needs further evaluation.
Fig. 1 Scatter diagram of the correlation between fetuin A and HbA1c levels in whole pregnant women
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In the current study, we found a significant correlation between fetuin A and HbA1c levels. Indeed, the possible association between fetuin A and glycemic control parameters remained unknown in patients with GDM, since the previous studies did not mention the association of fetuin A and fasting blood glucose or HbA1c [14, 15]. Therefore, our result showing positive relationship between fetuin A and HbA1c is a new finding in GDM. Consistent with our result, it has been reported that serum fetuin A levels were higher in type 2 diabetic subjects with HbA1c C 7.0 % than those with\6.5 % [23]. On the other hand, there are some studies reporting negative or no correlation between fetuin A and HbA1c in patients with type 2 DM [21, 24]. Although available data for type 2 DM are controversial, our result suggests that glycemic control reflected by HbA1c might influence circulating fetuin A levels in women with GDM. Some studies showed a positive relation of fetuin A with lipid parameters in type 2 DM [7, 25]. We observed in our study that fetuin A levels are significantly correlated with total cholesterol and triglycerides levels. Regarding this association, especially with triglycerides, some authors proposed a possible interaction between circulating fetuin A and free fatty acids [26]. Also, it has been suggested that fetuin A may have a role in lipid-induced insulin resistance [27]. However, future research may enlighten the relationship between fetuin A and lipids. Limitations of the present study are the cross-sectional nature and relatively small sample size of our study similar to other studies on GDM. Larger prospective studies are necessary to identify the possible causal relationship between fetuin A and the development of GDM. In conclusion, our results showed that serum fetuin A concentrations increased in women with GDM and decreased after delivery. Although our study could not demonstrate a possible causal role of fetuin A by inhibiting insulin receptor activity in the development of GDM, fetuin A might have a role in the metabolic changes including glycemic control and lipid alterations in GDM and contribute to the development of insulin resistance in GDM. Acknowledgments We gratefully thank Elif Ayvali for helping in laboratory analysis. Conflict of interest
There is no conflict of interest to disclose.
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3. Stefan N, Hennige AM, Staiger H, Machann J, Schick F, Krober SM, Machicao F, Fritsche A, Haring HU (2006) Alpha2-Heremans-Schmid glycoprotein/fetuin-A is associated with insulin resistance and fat accumulation in the liver in humans. Diabetes Care 29(4):853–857 4. Enli Y, Fenkci SM, Fenkci V, Oztekin O (2013) Serum Fetuin-A levels, insulin resistance and oxidative stress in women with polycystic ovary syndrome. Gynecol Endocrinol 29(12):1036–1039. doi:10.3109/09513590.2013.829442 5. Ou HY, Yang YC, Wu HT, Wu JS, Lu FH, Chang CJ (2011) Serum fetuin-A concentrations are elevated in subjects with impaired glucose tolerance and newly diagnosed type 2 diabetes. Clin Endocrinol 75(4):450–455. doi:10.1111/j.1365-2265.2011.04070.x 6. Singh M, Sharma PK, Garg VK, Mondal SC, Singh AK, Kumar N (2012) Role of fetuin-A in atherosclerosis associated with diabetic patients. J Pharm Pharmacol 64(12):1703–1708. doi:10. 1111/j.2042-7158.2012.01561.x 7. Song A, Xu M, Bi Y, Xu Y, Huang Y, Li M, Wang T, Wu Y, Liu Y, Li X, Chen Y, Wang W, Ning G (2011) Serum fetuin-A associates with type 2 diabetes and insulin resistance in Chinese adults. PLoS One 6(4):e19228. doi:10.1371/journal.pone. 0019228 8. Sun Q, Cornelis MC, Manson JE, Hu FB (2013) Plasma levels of fetuin-A and hepatic enzymes and risk of type 2 diabetes in women in the US. Diabetes 62(1):49–55. doi:10.2337/db12-0372 9. Mathews ST, Chellam N, Srinivas PR, Cintron VJ, Leon MA, Goustin AS, Grunberger G (2000) Alpha2-HSG, a specific inhibitor of insulin receptor autophosphorylation, interacts with the insulin receptor. Mol Cell Endocrinol 164(1–2):87–98 10. Catalano PM (2014) Trying to understand gestational diabetes. Diabet Med 31(3):273–281. doi:10.1111/dme.12381 11. Huopio H, Cederberg H, Vangipurapu J, Hakkarainen H, Paakkonen M, Kuulasmaa T, Heinonen S, Laakso M (2013) Association of risk variants for type 2 diabetes and hyperglycemia with gestational diabetes. Eur J Endocrinol 169(3):291–297. doi:10.1530/EJE-13-0286 12. Kim C, Newton KM, Knopp RH (2002) Gestational diabetes and the incidence of type 2 diabetes: a systematic review. Diabetes Care 25(10):1862–1868 13. Barbour LA, McCurdy CE, Hernandez TL, Friedman JE (2011) Chronically increased S6K1 is associated with impaired IRS1 signaling in skeletal muscle of GDM women with impaired glucose tolerance postpartum. J Clin Endocrinol Meta 96(5):1431–1441. doi:10.1210/jc.2010-2116 14. Kalabay L, Cseh K, Pajor A, Baranyi E, Csakany GM, Melczer Z, Speer G, Kovacs M, Siller G, Karadi I, Winkler G (2002) Correlation of maternal serum fetuin/alpha2-HS-glycoprotein concentration with maternal insulin resistance and anthropometric parameters of neonates in normal pregnancy and gestational diabetes. Eur J Endocrinol 147(2):243–248 15. Farhan S, Handisurya A, Todoric J, Tura A, Pacini G, Wagner O, Klein K, Jarai R, Huber K, Kautzky-Willer A (2012) Fetuin-A characteristics during and after pregnancy: result from a case control pilot study. Int J Endocrinol 2012:896736. doi:10.1155/ 2012/896736 16. Coustan DR, Carpenter MW (1998) The diagnosis of gestational diabetes. Diabetes Care 21(Suppl 2):B5–B8 17. Friedewald WT, Levy RI, Fredrickson DS (1972) Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem 18(6):499–502 18. Denecke B, Graber S, Schafer C, Heiss A, Woltje M, JahnenDechent W (2003) Tissue distribution and activity testing suggest a similar but not identical function of fetuin-B and fetuin-A. Biochem J 376(Pt 1):135–145. doi:10.1042/BJ20030676
Arch Gynecol Obstet 19. Olivier E, Soury E, Ruminy P, Husson A, Parmentier F, Daveau M, Salier JP (2000) Fetuin-B, a second member of the fetuin family in mammals. Biochem J 350(Pt 2):589–597 20. Briana DD, Boutsikou M, Gourgiotis D, Boutsikou T, Baka S, Marmarinos A, Hassiakos D, Malamitsi-Puchner A (2008) Serum fetuin-A/alpha2-HS-glycoprotein in human pregnancies with normal and restricted fetal growth. J Matern Fetal Neonatal Med 21(11):826–830. doi:10.1080/14767050802326255 21. Gunduz FO, Yildirmak ST, Temizel M, Faki Y, Cakmak M, Durmuscan M, Sezgin F (2011) Serum visfatin and fetuin-a levels and glycemic control in patients with obese type 2 diabetes mellitus. Diabetes Metab J 35(5):523–528. doi:10.4093/dmj. 2011.35.5.523 22. Erdmann J, Salmhofer H, Knauss A, Mayr M, Wagenpfeil S, Sypchenko O, Luppa P, Schusdziarra V (2012) Relationship of fetuin-A levels to weight-dependent insulin resistance and type 2 diabetes mellitus. Regul Pept 178(1–3):6–10. doi:10.1016/j. regpep.2012.02.004 23. Liu Y, Xu M, Xu Y, Li M, Wang T, Chen Y, Bi Y (2012) Positive correlation between chronic hyperglycemia and serum fetuin-A
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levels in middle-aged and elderly Chinese. J Diabetes 4(4):351–358. doi:10.1111/1753-0407.12000 Ozyazgan S, Karaoglu K, Kurt A, Altinok A, Konukoglu D, Osar Siva Z, Andican G (2013) Effects of omega-3 polyunsaturated fatty acid supplementation on serum fetuin-A levels in type 2 diabetic patients. Minerva Med 104(3):287–293 Jung CH, Kim BY, Kim CH, Kang SK, Jung SH, Mok JO (2013) Associations of serum fetuin-A levels with insulin resistance and vascular complications in patients with type 2 diabetes. Diab Vasc Dis Res 10(5):459–467. doi:10.1177/1479164113490766 Stefan N, Haring HU (2013) Circulating fetuin-A and free fatty acids interact to predict insulin resistance in humans. Nat Med 19(4):394–395. doi:10.1038/nm.3116 Pal D, Dasgupta S, Kundu R, Maitra S, Das G, Mukhopadhyay S, Ray S, Majumdar SS, Bhattacharya S (2012) Fetuin-A acts as an endogenous ligand of TLR4 to promote lipid-induced insulin resistance. Nat Med 18(8):1279–1285. doi:10.1038/nm.2851
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GYNECOLOGIC ENDOCRINOLOGY AND REPRODUCTIVE MEDICINE
Serum levels of fetuin A are increased in women with gestational diabetes mellitus Ozlem Turhan Iyidir • Ceyla Konca Degertekin • Banu Aktas Yilmaz • Alev E. Altinova • Fusun B. Toruner Nuray Bozkurt • Goksun Ayvaz • Mujde Akturk
•
Received: 30 May 2014 / Accepted: 22 September 2014 Ó Springer-Verlag Berlin Heidelberg 2014
Abstract Purpose Fetuin A is associated with insulin resistance and type 2 diabetes mellitus (DM). We aimed to investigate circulating fetuin A concentrations in gestational diabetes mellitus (GDM). Methods Serum fetuin A levels were studied in 26 pregnant women with GDM and 24 healthy pregnant women between 24th and 28th gestational weeks. Fetuin A levels were also evaluated in 18 of women with GDM at postpartum. Results Fetuin A concentrations were significantly increased in women with GDM compared to healthy pregnant women (35.0 ± 3.2 vs. 32.0 ± 4.4 ng/ml; p = 0.01). Also, fetuin A levels in women with GDM significantly decreased at postpartum period (35.0 ± 3.2 vs. 31.7 ± 3.9 ng/ml; p = 0.001). In whole pregnant women, there were positive correlations between fetuin A and HbA1c (r = 0.418, p = 0.002), total cholesterol (r = 0.332, p = 0.018) and triglycerides (r = 0.306, p = 0.031). Multivariate regression analysis demonstrated that HbA1c was the important predictor of circulating fetuin A level (beta = 0.375, p = 0.01). Conclusion In conclusion, our results indicate that serum fetuin A concentrations are increased in women with GDM and decreased after delivery.
O. T. Iyidir (&) C. K. Degertekin B. A. Yilmaz A. E. Altinova F. B. Toruner G. Ayvaz M. Akturk Department of Endocrinology and Metabolism, Gazi University Faculty of Medicine, Ankara, Turkey e-mail: [email protected] N. Bozkurt Department of Obstetrics and Gynecology, Gazi University Faculty of Medicine, Ankara, Turkey
Therefore, fetuin A might have a role in the development of insulin resistance and the metabolic changes in GDM. Keywords Gestational diabetes mellitus Fetuin A Lipids HbA1c
Introduction Fetuin A which is also known as a2-HS-glycoprotein (AHSG) is a multifunctional glycoprotein, mainly synthesized in the liver [1]. It has several roles particularly on vascular calcification and bone metabolism [2]. Crosssectional studies have demonstrated that high fetuin A concentrations are associated with insulin resistance [3], polycystic ovary syndrome [4] and type 2 diabetes mellitus (DM) [5–7]. Moreover, a prospective study revealed that plasma fetuin A is related to an increased risk for the development of DM in women [8]. Regarding this relationship between fetuin A and insulin resistance, a direct inhibitory effect of fetuin A has been shown on insulin receptor autophosphorylation in skeletal muscle and hepatocytes [9]. Gestational diabetes mellitus (GDM) develops when there is an impairment of the compensatory increase in insulin secretion from the beta cells to overcome insulin resistance seen in pregnancy [10]. GDM and type 2 DM have similar pathogenetic mechanisms as well as genetic factors and the women with previous GDM have increased risk of type 2 DM [11, 12]. Although the exact mechanisms related to the insulin resistance seen in GDM are not fully known, decreased tyrosine phosphorylation of insulin receptor and insulin receptor substrate 1 have been shown in GDM [13].
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Taking the negative effect of fetuin A on tyrosine kinase signaling into account, one can suggest that fetuin A may play a role in the development of insulin resistance in GDM. However, there are limited studies investigating fetuin A levels in women with GDM. Kalabay et al. showed increased levels of fetuin A in women with GDM compared with healthy pregnant women [14]. In contrast to this study, no difference was found in fetuin A levels during OGTT at third trimester of the pregnancy and postpartum period between women with GDM and healthy pregnant controls [15]. Therefore, we aimed to assess whether circulating fetuin A concentrations are altered and related to the metabolic changes in women with GDM.
Materials and methods We analyzed the data of 26 pregnant women with GDM and 24 age and body mass index (BMI)-matched women with healthy pregnancies as controls. All pregnant women included in this study were screened for GDM using a 50-g glucose challenge test (GCT). Women with a 1-h glucose level of 140 mg/dl or more proceeded to 100-g oral glucose tolerance test (OGTT) using Carpenter and Coustan guidelines [16]. Women with two or more abnormal values were diagnosed as having GDM. None of the pregnant women included in this study had preeclampsia, eclampsia, pregnancy-induced hypertension or history of hypertension before pregnancy. None of the patients had history of alcohol before pregnancy. Thirteen women with GDM (50.0 %) were treated with insulin therapy in addition to diet during pregnancy. The study protocol was approved by
the local Ethics Committee. All patients gave written informed consent before taking part in the study. Fasting blood samples were obtained from all participants between 24th and 28th gestational weeks. Eighteen of 26 patients with GDM were reevaluated after 3 months postpartum. Blood samples were centrifuged and stored at -80 °C until being studied. The lipid parameters (total cholesterol, HDL cholesterol and triglycerides) were measured by standardized methods using autoanalysers. LDL cholesterol levels were calculated according to the formula described by Friedewald et al. [17]. Glycosylated hemoglobin (HbA1c) levels were determined using Agilent Technologies 1200 Series analyzer with commercially available kits by HPLC method (Chromsystems Instruments and Chemicals GmbH. Mu¨nchen, Germany). Serum fetuin A was measured with enzyme-linked immunosorbent assay (ELISA) according to the manufacturer’s instructions (Bio Vendor Laboratory Medicine Inc. Brno, Czech Republic). Serum high-sensitive C-reactive protein (hs-CRP) was determined using a commercially available sandwich ELISA kit (DRG International, USA). Statistical analysis Statistical analyses were performed using the SPSS software version 16. Continuous data were presented as mean ± standard deviation or medians (minimum–maximum) as appropriate. The level of significance was determined using the t test for normally distributed values and the Mann–Whitney U test was used for non-normally distributed values. Paired t test was used for comparison
Table 1 Characteristics of women with GDM in pregnancy and postpartum and healthy pregnant controls
Age (years) 2
GDM (n = 26)
Postpartum GDM (n = 18)
Pregnant controls (n = 24)
31.3 ± 5.3
30.6 ± 4.7
29.6 ± 5.4
p1 0.274
p2 –
BMI (kg/m )
29.1 ± 5.2
27.1 ± 5.4
27.5 ± 3.6
0.217
\0.001
Fasting blood glucose (mg/dl)
86.5 (72.0–106.0)
92.0 (73.0–111.0)
77.0 (68.0–81.0)
\0.001
0.104
HbA1c (%)
5.4 (5.0–6.4)
5.2 (4.8–6.0)
5.0 (4.5–5.6)
\0.001
0.171
Total cholesterol (mg/dl) LDL cholesterol (mg/dl)
259.3 ± 51.8 147.0 ± 51.7
204.1 ± 30.0 127.9 ± 30.4
233.5 ± 56.6 130.6 ± 40.1
0.099 0.251
\0.001 0.198
HDL cholesterol (mg/dl)
60.5 ± 14.6
54.1 ± 13.0
61.6 ± 14.6
0.802
0.025 \0.001
Triglycerides (mg/dl)
248.7 ± 93.8
114.3 ± 51.0
203.7 ± 72.4
0.065
Hs-CRP (mg/l)
4.4 ± 2.6
2.5 ± 2.1
4.3 ± 2.4
0.936
0.006
Fetuin-A (ng/ml)
35.0 ± 3.2
31.7 ± 3.9
32.0 ± 4.4
0.01
0.001
Data were given as mean ± SD or median (minimum–maximum) GDM gestational diabetes mellitus, BMI body mass index, LDL low-density lipoprotein, HDL high-density lipoprotein, hs-CRP high-sensitive C-reactive protein 1 p GDM vs. pregnant controls 2
p GDM vs. postpartum GDM
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within GDM group before and after delivery. Correlation analyses were performed using Pearson’s coefficients. Spearman’s test was used when necessary. p value of\0.05 was considered statistically significant.
cholesterol and triglycerides as independent variables revealed that HbA1c was the important predictor of circulating fetuin A levels (r2 = 0.266, beta = 0.375, p = 0.01).
Results
Discussion
Table 1 shows the characteristics of women with GDM in pregnancy and postpartum and healthy pregnant controls. There was no significant difference in terms of age, gestational age and BMI between GDM and control group (p [ 0.05). When compared to control group, women with GDM had high levels of fasting blood glucose (88.3 ± 10.3 vs. 75.7 ± 3.4 mg/dl; p \ 0.001) and HbA1c (5.4 ± 0.3 vs. 5.0 ± 0.2 %; p \ 0.001). GDM and control group were similar in terms of total cholesterol (259.3 ± 51.8 vs. 233.5 ± 56.6 mg/dl; p = 0.099), LDL cholesterol (147.0 ± 51.7 vs. 130.6 ± 40.1 mg/dl; p = 0.251), HDL cholesterol (60.5 ± 14.6 vs. 61.6 ± 14.6 mg/dl; p = 0.802) and triglycerides (248.7 ± 93.8 vs. 203.7 ± 72.4 mg/dl; p = 0.065). There was also no significant difference in hs-CRP levels between GDM and control group (4.4 ± 2.6 vs. 4.3 ± 2.4 mg/l; p = 0.936). Serum fetuin A levels were found to be significantly increased compared to control group (35.0 ± 3.2 vs. 32.0 ± 4.4 ng/ml; p = 0.01). In 18 postpartum women with GDM, 13 (72.2 %) patients had normal glucose tolerance, 4 (22.2 %) had impaired fasting glucose and 1 (5.6 %) had impaired glucose tolerance. Serum fetuin A concentrations in women with GDM significantly decreased at postpartum period (35.0 ± 3.2 vs. 31.7 ± 3.9 ng/ml; p = 0.001). In whole pregnant women, there were positive correlations between fetuin A and HbA1c (r = 0.418, p = 0.002) (Fig. 1), total cholesterol (r = 0.332, p = 0.018) and triglycerides (r = 0.306, p = 0.031). Multivariate linear regression analysis including fetuin A as dependent variable and age, BMI, HbA1c, total
Our results showed that serum fetuin A levels are significantly increased in patients with GDM as compared with healthy pregnant controls and decreased after delivery. These findings imply that circulating fetuin A may contribute to the pathogenesis of the GDM possibly through tyrosine phosphorylation. The present study is in accordance with one of the previous studies reporting elevated serum fetuin A (AHSG) levels in women with GDM in the 20–40th gestational weeks compared to healthy pregnant women during all trimesters of pregnancy and non-pregnant controls [14]. Kalabay et al. [14] also showed that fetuin A levels were increased in pregnancy and positive correlations between fetuin A and measurable parameters of insulin resistance such as C-peptide and C-peptide/blood glucose ratio, as well. Therefore, our results confirm an earlier study by Kalabay et al. [14]. But, they did not evaluate the women with GDM at postpartum period. The other previous study reported that maternal fasting fetuin A and fetuin A after 75 gr glucose load did not differ between pregnant women with and without GDM at 28th week of gestation as well as 3 months after delivery [15]. The lack of alteration in fetuin A levels in that study may be related to their study size because their patient number was relatively low. Fetuin A expression has been shown in the placenta [18]. Moreover, high level of fetuin A was identified in fetal life [19]. Maternal and fetal fetuin A levels were found to be similar and correlated with each other in normal pregnancy suggesting transplacental transfer [20]. However, there is not any data about the importance of the increased fetuin A in terms of fetuses of women with GDM. Future studies are needed to clarify this question. Regarding the relationship between fetuin A and type 2 DM, a community-based study revealed increased fetuin A concentrations are associated with insulin resistance and type 2 DM in middle-aged and elderly Chinese [7]. Although most of the studies demonstrated high levels of fetuin A in patients with type 2 DM [5, 6], a previous study reported significantly lower serum fetuin A concentrations in type 2 DM than controls [21]. Moreover, similar fetuin A levels have been shown between type 2 DM and nondiabetic subjects in another study [22] The reason of these contrast results related to fetuin A concentrations in type 2 DM needs further evaluation.
Fig. 1 Scatter diagram of the correlation between fetuin A and HbA1c levels in whole pregnant women
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In the current study, we found a significant correlation between fetuin A and HbA1c levels. Indeed, the possible association between fetuin A and glycemic control parameters remained unknown in patients with GDM, since the previous studies did not mention the association of fetuin A and fasting blood glucose or HbA1c [14, 15]. Therefore, our result showing positive relationship between fetuin A and HbA1c is a new finding in GDM. Consistent with our result, it has been reported that serum fetuin A levels were higher in type 2 diabetic subjects with HbA1c C 7.0 % than those with\6.5 % [23]. On the other hand, there are some studies reporting negative or no correlation between fetuin A and HbA1c in patients with type 2 DM [21, 24]. Although available data for type 2 DM are controversial, our result suggests that glycemic control reflected by HbA1c might influence circulating fetuin A levels in women with GDM. Some studies showed a positive relation of fetuin A with lipid parameters in type 2 DM [7, 25]. We observed in our study that fetuin A levels are significantly correlated with total cholesterol and triglycerides levels. Regarding this association, especially with triglycerides, some authors proposed a possible interaction between circulating fetuin A and free fatty acids [26]. Also, it has been suggested that fetuin A may have a role in lipid-induced insulin resistance [27]. However, future research may enlighten the relationship between fetuin A and lipids. Limitations of the present study are the cross-sectional nature and relatively small sample size of our study similar to other studies on GDM. Larger prospective studies are necessary to identify the possible causal relationship between fetuin A and the development of GDM. In conclusion, our results showed that serum fetuin A concentrations increased in women with GDM and decreased after delivery. Although our study could not demonstrate a possible causal role of fetuin A by inhibiting insulin receptor activity in the development of GDM, fetuin A might have a role in the metabolic changes including glycemic control and lipid alterations in GDM and contribute to the development of insulin resistance in GDM. Acknowledgments We gratefully thank Elif Ayvali for helping in laboratory analysis. Conflict of interest
There is no conflict of interest to disclose.
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