Endocrine Abstracts

Introduction: Visceral adipose tissue-derived serine protease inhibitor (vaspin) is a novel adipocytokine which might exert an insulin-sensitizing effect. It is thought that vaspin mRNA expression may be a compensatory mechanism associated with obesity and insulin resistance. Given the fact that subclinical and overt hypothyroidism are known risk factors for insulin resistance, we aimed to assess the regulation of vaspin by thyroid hormones in humans.

Methods: We enrolled 32 overt hypothyroid, 42 subclinical hypothyroid and 37 euthyroid patients in the study. We evaluated the body mass index (BMI), fasting glucose, lipid profile, TSH, free T₃, free T₄, fasting insulin and vaspin levels. Vaspin levels were determined by ELISA (ng/ml). We calculated the HOMA-IR index. We evaluated the change in vaspin levels in 16 overt hypothyroid patients after replacement of thyroid hormones.

Results: Overt hypothyroid patients were significantly older (P<0.05) and had higher BMI values (P<0.05) than subclinical and euthyroid patients. A significant difference in fasting glucose, triglyseride, HDL, LDL levels was found between the groups (P<0.05). However there was no significant difference in total cholesterol, insulin levels and HOMA-IR (P>0.05). Vaspin levels were not different between the groups (mean of vaspin levels in overt, subclinical and euthyroid patients respectively 1.13±0.8, 1.32±1.08, 1.03±0.76 ng/ml P>0.05). No significant association was observed between vaspin levels and BMI, fasting glucose, insulin and HOMA-IR (P>0.05). After replacement of thyroid hormones in overt thyroid patients, there was no siginificant change in serum vaspin levels (before and after treatment respectively, 1.23±0.94; 1.23±0.07 ng/ml P>0.05).

Conclusion: Although, in animal studies vaspin mRNa levels were shown to be down-regulated in hyperthyroid rats and increased in hypothyroid rats, we could not replicate these findings in humans. It’s likely that thyroid hormones have no considerable effect on the regulation of vaspin in humans.