Endocrine Abstracts

Background

Hypothyroidism due to autoimmune thyroiditis (AITD) leads to atherogenic lipid profile and therefore might increase the cardiovascular risk of patients. Fetuin-A is a hepatokine with a role in the regulation of mineralization, metabolism and the cardiovascular system. Fetuin-A levels are known increased in obesity-linked diseases. To date, the role of fetuin-A in autoimmune thyroiditis has not been thoroughly investigated.

Subjects and methods

In our study we investigated the association between thyroid hormone levels, thyroid antibodies, the components of lipid metabolism, anthropometrical parameters and fetuin-A. We enrolled eighty-six patients (7 men, 79 women, mean age 43 ± 13 years, median BMI 25.3 (23.4–30.5) kg/m²) from the outpatient clinic of Endocrine Department of University of Debrecen, Faculty of Medicine. All patients had autoimmune thyroiditis with various thyroid hormone status from hypo- to hyperthyroidism. Serum fetuin-A concentrations were determined with enzyme-linked immunosorbent assay (ELISA). Thyroid hormone levels, anti-thyroperoxidase (aTPO) concentration and lipid parameters were measured by routine laboratory methods.

Results

Median serum fetuin-A level was 929.7 (822.0 – 1038.3) mg/l, LDL-C was 3.2 (2.6–3.8) mmol/l, HDL-C was 1.5 (1.3–1.8), triglyceride was 0.84 (0.49–1.45) mmol/l, while mean total cholesterol level was 5.3 ± 1.1 mmol/l. Mean fT3 and fT4 were 4.67 ± 0.67 and 17.8 ± 3.6 pmol/l, respectively. Significant positive correlation was found between fT3 and fetuin-A levels (r = 0.273, P = 0.013). There was a significant negative correlation between age (r = -0.406; P<0.001), daily levothyroxine dose/body weight (r_s = -0.370, P = 0.001), total cholesterol (r = -0.287, P<0.01), ApoB100 (r = -0.300, P<0.01) and fT3. However, we could not find correlation between fetuin-A and aTPO levels. Among patients receiving levothyroxine substitution, a correlation between CRP and fT3 was present (r = -0.251, P = 0.047).

Conclusions

The significant correlation between fetuin-A and fT3 levels might indicate a regulatory effect of T3 on metabolism. However, further clinical investigations are needed to clarify this relationship.