Association between Serum Osteopontin Levels and Cardiovascular Risk in Hypothyrodism

Abstract

Purpose: Cardiovascular effects of hypothyroidism are well known. Osteopontin (OPN) is a new inflammatory marker which was first isolated from the bone. Flow-mediated dilatation (FMD), a noninvasive technique to measure this endothelium-dependent function, has been used in several clinical studies to show cardiovascular risks. The aim of our study was to assess FMD value in hypothyroidism patients and to investigate whether plasma OPN level is a parameter which can predict cardiovascular risks in this group of patients.

Material and Method: This study included 39 patients who had high levels of thyroid-stimulating hormone (TSH) and 11 healthy euthyroid controls. Plasma TSH, free thyroxine, fibrinogen, high-sensitive C-reactive protein (hsCRP), fasting plasma glucose, total cholesterol (T-chol), low density lipoprotein (LDL), triglyceride and OPN levels were measured at the time hypothyroidism was first detected and after euthyroid state was achieved with levothyroxine treatment. In parallel with these assessments, brachial FMD measurements were also performed.

Results: In hypothyroid patients cardiovascular risk factors such as T-chol, LDL and triglyceride levels were higher than in control group but fibrinogen and hsCRP levels were not different between the groups. OPN levels were similar in patient and control groups, but basal FMD levels were lower in patients with hypothyroidism. After euthyroidism was achieved, OPN levels significantly decreased and FMD levels significantly increased, but a correlation was not detected between these two parameters.

Discussion: Our study did not show a significant correlation between OPN and cardiovascular risk parameters. Further studies are needed to use OPN as a cardiovascular risk marker in hypothyroid patients.