Study of Irisin Hormone level in Type 2 Diabetic Patients and Patients with Diabetic Neuropathy

Abstract

Type 2 diabetes is a metabolic disease characterized by hyperglycemia resulting from insulin resistance and usually relative (rather than absolute) insulin deficiency and accounts for about 90–95% of diabetic patients. Diabetic polyneuropathy (DPN) is one of the most common long-term complications of diabetes affecting ~50% of all diabetic people and is thought to be the most common variety, which develops on (or with) a background of longstanding hyperglycemia, associated metabolic derangements. Irisin hormone is normally present as part of a larger protein Fibronectin domain-containing protein 5 (FNDC5) in a muscle cell’s outer membrane released by exercise. It is involved in insulin resistance and type 2 diabetes and reported that it is decreased in patients with type 2 diabetes. Other target of irisin is nervous system and might have a role in the nervous system induces neural proliferation and adequate neural differentiation. The aim of this work was to study the relation between irisin hormone level in Type 2 diabetic patients and insulin resistance as well as study the relation between irisin hormone level and diabetic neuropathy. The study was conducted on 90 subjects who divided into 3 groups: Group 1: 30 type 2 diabetic patients without neuropathy. Group 2: 30 type 2 diabetic patients with diabetic neuropathy. Group 3: 30 Control subjects with matched age and sex and not diabetics. Criteria included patients with type 2 diabetes with age range from 35 to 60 years old and we excluded pregnant females, patients with renal or hepatic diseases and patients whom receiving simvastatins. All individuals of this study were submitted to full medical history (tingling, numbness, lancinating pain and medication), physical examination (height and weight for BMI, hypertension and neurological examination), doing DN4 questionnare as a screen test for diabetic neuropathy and measurement of fasting, 2 hrs post - prandial blood glucose level, HbA1c, fasting serum insulin, fasting serum irisin hormone, insulin resistance & sensitivity calculated by HOMA-IR and HOMA-β. Our results denoting: • Irisin hormone level is significantly decreased in type 2 diabetic patients (40.92 ± 17.9 ng/ml) in comparison with normal subjects (160.14 ± 58.67 ng/ml ). • Irisin hormone level is significantly decreased in patients with diabetic neuropathy (27.57 ± 7.61 ng/ml) compared to diabetic patients without neuropathy (54.27 ± 15.24 ng/ml). • There is a high significant (P < 0.01) negative correlation between irisin level and glycemic control [FBG (r =-0.487), 2h BG (r = -0.570) and HbA1c (r = -0.596)] and insulin resistance state (r = - 0.441). • Fasting insulin has a negative relationship (r = -0.368) with fasting serum irisin hormone level (P < 0.01).