Resistin Serum Levels Are Increased but Not Correlated with Insulin Resistance in Chronic Hemodialysis Patients

Abstract

Background/Aims: Insulin resistance is a well-known phenomenon in uremia. Resistin, a recently discovered insulin inhibitor secreted by adipocytes, is associated with obesity and insulin resistance in mice. Adiponectin, also secreted by adipocytes, is known to reduce insulin resistance in humans. The aim of the present study was to address the hypothesis that changes in resistin or adiponectin serum levels may relate to body composition and to insulin resistance in patients with end-stage renal disease. Methods: In a cross-sectional study, 33 non-diabetic patients (24 males and 9 females, mean age 61.5 ± 15.8 years) with end-stage renal disease on chronic hemodialysis (treatment duration 41 ± 31 months) that lacked signs of infection were enrolled. The control group consisted of 33, matched for age, sex and body mass index (BMI), healthy volunteers (22 males, 11 females, mean age 62.6 ± 12.1 years). BMI (kg/m²) was calculated from body weight and height. Body fat (%) was measured by means of bioelectrical impedance. Blood samples were taken always in the morning after a 12-hour fasting period before and after the hemodialysis session. Resistin and adiponectin serum concentrations were measured by enzyme immunoassays and insulin by an electrochemiluminescence immunoassay. The post-treatment values were corrected regarding the hemoconcentration. The homeostasis model assessment index (HOMA-R) was calculated as an estimate of insulin resistance from the fasting glucose and insulin serum levels. Results: Pre-treatment resistin serum levels were significantly increased in hemodialysis patients compared to healthy controls (19.2 ± 6.2 vs. 3.9 ± 1.8 ng/ml; p < 0.001). Hemodialysis did not alter resistin levels, as pre- and post-treatment levels were not different when corrected for hemoconcentration (19.2 ± 6.2 vs. 18.7 ± 5.0 ng/ml; p = 0.54). Adiponectin levels were also increased in hemodialysis patients compared to healthy controls (25.4 ± 21.5 vs. 10.5 ± 5.9 µg/ml; p < 0.001). A significant inverse correlation was observed between the serum adiponectin levels before the hemodialysis session on the one hand and the BMI (r = –0.527, p = 0.002), the HOMA-R (r = –0.378, p < 0.05) and the fasting insulin levels (r = –0.397, p < 0.05) on the other. However, no significant correlation was observed between serum resistin levels on the one hand versus HOMA-R index (3.2 ± 3.9 mmol·µIU/ml; r = –0.098, p = 0.59), insulin levels (13.3 ± 14.4 mU/l; r = –0.073, p = 0.69), glucose levels (89 ± 13 mg/dl; r = –0.049, p = 0.78), BMI (25.6 ± 3.7 kg/m²; r = –0.041, p = 0.82) and body fat content (26.4 ± 8.4%; r = –0.018, p = 0.94) on the other hand. Conclusion: Resistin serum levels are significantly elevated in non-diabetic patients with end-stage renal disease that are treated by hemodialysis. The hemodialysis procedure does not affect the resistin levels. Along with previous observations in patients with renal insufficiency in the pre-dialysis stage, our findings implicate an important role of the kidney in resi...

Adipose tissue in control of metabolism

“…However, the correlation between resistin and obesity remains controversial. In humans, some studies showed that the circulating levels of resistin are increased during ageing and are elevated in obese and diabetic individuals (Degawa- Yamauchi et al 2003, Oliver et al 2003, Gerber et al 2005 while others reported that the circulating levels of resistin are not correlated with obesity and insulin resistance (Lee et al 2003, Filippidis et al 2005, Hasegawa et al 2005, Iqbal et al 2005. Besides, several animal studies show that the mRNA levels of resistin in adipose tissue are downregulated in adipose tissue of obese animals, and are not associated with circulating levels of insulin or glucose (Le Lay et al 2001, Milan et al 2002, Lee et al 2005.…”

Serum resistin correlates with central obesity but weakly with insulin resistance in Chinese children and adolescents

“…19 It was positively correlated with pro-inflammatory factors in adults with pathophysiological conditions such as atherosclerosis, renal disease and inflammation of respiratory tracts. [20][21][22][23][24][25][26][27] Proinflammatory molecules such as tumor necrosis factor-a, interleukin-6 and lipopolysaccharide regulate resistin gene expression in various cell models 28 and reciprocal modulation has been hypothesized. 29 Resistin is clearly involved in inflammation, but its specific function in that situation remains to be clarified.…”

Plasma resistin levels correlate with determinants of the metabolic syndrome

“…In humans, data on the role of this adipokine in insulin sensitivity and obesity are controversial (16). Some authors indicated that increased serum resistin levels are associated with increased obesity, visceral fat (4,17,18), insulin resistance, and type 2 diabetes (19,20), while other groups failed to observe such correlations (20)(21)(22)(23). Savage et al have shown that resistin mRNA expression is high in circulating mononuclear cells, while it is low in adipocytes and almost undetectable in preadipocytes, endothelial cells, and smooth muscle cells (24); thus suggesting the possibility that different sources of resistin could be responsible for the different effects observed in mice and humans.…”