Serum resistin is not associated with obesity or insulin resistance in humans

N. Iqbal1,2, P. Seshadri1,2, L. Stern1, J. Loh2, S. Kundu3, T. Jafar4, F.F. Samaha5

1 Department of Medicine, Section of Endocrinology Diabetes and Metabolism, Philadelphia VA
Medical Center, Philadelphia, Pennsylvania (USA)
2 Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (USA)
3 Department of Medicine, Pennsylvania Hospital, Philadelphia, PA (USA)
4 Department of Medicine, Section of Nephrology, Aga Khan University, Karachi (Pakistan)
5 Department of Medicine, Section of Cardiology, Philadelphia, VA Medical Center, Philadelphia, Pennsylvania (USA)

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• Endocrinology

Abstract. – Background: Resistin has proposed link with obesity related insulin resistance and type 2 diabetes. The physiologic role of resistin in humans remains unknown. It is suggested that circulating resistin levels are not associated with obesity or insulin resistance in humans. However, the effects of weight loss on serum resistin concentration has not been studied. In order to better understand the physiologic role of resistin in human obesity, we measured the serum resistin concentration in subjects with severe obesity (before and after 6-months of dietary intervention) to test the hypothesis that serum resistin concentrations are elevated amongst individuals with severe obesity and weight loss would reduce these levels. Methods: Seventy-one obese subjects (defined as BMI > 35 kg/m2) who were randomized to low fat (LF) vs low carbohydrates (LC) diets and who completed the 6-month follow-up were studied. Their baseline demographic information was collected and serum resistin, insulin, glucose were measured at baseline and at 6-months. Results: Subjects in LC diet lost more weight than LF (-19.54 +/- 7.87 lbs vs -7.83 +/- 11.23 lbs, p = 0.001). Insulin sensitivity (HOMA) improved in LC group compared with LF group [-3.72 +/- 9.84 (LC) vs +1.31 +/- 7.31 (LF), p = 0.006]. Serum resistin levels did not decrease in either diet. Conclusions: Our study found that despite a significant weight loss and improvement in insulin sensitivity there was no reduction in serum resistin concentration in morbidly obese men with metabolic syndrome suggesting that resistin does not play a central role in obesity related insulin resistance.