ABSTRACT
Background: irisin, identified as a proteolytic cleavage product of the fibronectin type III domain-containing protein 5 [FNDC5], It is a novel myokine secreted by contracting skeletal muscle, possibly mediating some exercise health benefits via "browning" of white adipose tissue. Irisin causes a significant increase in total body energy expenditure and resistance to obesity-associated insulin resistance in mice, while controversy still exists concerning irisin origin, regulation and function in humans
Aim of the work: our study aimed to detect relation of thyroid status [hypo, hyperthyroid] with serum irisin, ck and peripheral neuropathy
Patient and methods: this study was conducted on 60 candidates consisted of 40 patients with thyroid dysfunction selected from Endocrine outpatient Clinic and Inpatient Department of Ain Shams University Hospitals and 20 healthy volunteers from April 2016 to October 2016. Informed consent was obtained from all participants. Patients of both genders, age more than 18 years old, 20 patients with hypothyroidism, 20 patients with hyperthyroidism and 20 healthy volunteers. We excluded significant renal, hepatic and cardiac disease, severe associated acute illness or depression, pregnant females, diabetes, hypercortisolism, hypocortisolism, muscular or neurological disorders, routinely taking drugs as statins, intensively involved in a sport or any strenuous physical activity. All participants were subjected to full medical history taking, general clinical examination and laboratory investigations as thyroid and thyroid-related hormone concentrations as well as a thyroid ultrasound examination and thyroid scan for patients with hyperthyroidism. Serum irisin level, CK and nerve conduction velocity were measured
Results: irisin level was higher in hyperthyroid group than euthyroid group with a significant difference. In comparison with normal NCV candidates and reduced NCV candidates with other variables there was only border line significant difference with irisin p-value. Non-significant value of irisin and CK level were detected for diagnosis of hypothyroidism. Irisin has highly significant value for diagnosis of hyperthyroidism with [sen 95%, sp 42.5]. Increased BMI is the only independent predictor for hypothyroidism by using multivariable binary logistic regression analysis. Decreased BMI and irisin are independent predictors for hyperthyroidism
Conclusion: serum irisin level is one of predictors for hyperthyroidism; on the other hand irisin does not have a significant value to predict hypothyroidism. Serum irisin was found to be higher in patients with hyperthyroidism in comparison with euthyroid participant with non-statistically significant difference between hypo and hyperthyroidism. Serum CK level does not have a significant value in diagnosis of thyroid dysfunction [hypothyroidism or hyperthyroidism]. Serum irisin level was low in thyroid dysfunction cases with delayed NCV compared to thyroid dysfunction cases and normal NCV with border line significant difference