Changes of Certain Metabolic and Cardiovascular Markers Fructosamine, H-FABP and Lipoprotein (a) in Patients with Hypothyroidism

Abstract

Background: Disorders of thyroid gland are common in general population, and it’s the most common affecting the endocrine system after diabetes mellitus. Thyroid function regulates a wide range of metabolic parameters, as well as affects some cardiovascular disease risk factors. Fructosamine is produced by a reaction between albumin (protein) and glucose; it is used to monitor patients with diabetes for short-term glycemic changes. H-FABP is present in the cytoplasm of cardiac myocytes, and delivers fatty acids into these cells. It has been shown to increase in myocardial injury. Lipoprotein LP(a) is consist of a special apolipoprotein called apoprotein (a), and it’s recognized as a cardiovascular disease independent risk factor. Objective: To study whether certain metabolic and cardiovascular markers (fructosamine, H-FABP and lipoprotein (a) are changed in hypothyroid patients. Methods: The current study included 280 overt hypothyroid, 272 with subclinical hypothyroidism compared with 270 healthy individuals of matched age and gender. For all subjects serum (TSH, T4, T3, FBS, HbA1c, fructosamine, triglycerides, cholesterol, lipoprotein (a), and Heart-type Fatty Acid-Binding Protein (H-FABP)) was measured. Results: Serum fructosamine level significantly elevated (p value <0.05) in patient with hypothyroidism when compared with control group, and no significant change between subclinical and control groups. There is no significant change in serum H-FABP between study subjects. There is significant increase in lipoprotein (a) in patient with hypothyroidism and those with subclinical group when compared with control group. Conclusion: Serum fructosamine and level is significantly changed in patients with overt hypothyroidism when compared with euthyroid subjects. Also, we conclude that hypothyroidism increase risk of cardiovascular diseases by changing non-traditional marker such as lipoprotein (a), and no effect on H-FABP concentration.

Recommendations of the Experts of the Polish Cardiac Society (PCS) and the Polish Lipid Association (PoLA) on the diagnosis and management of elevated lipoprotein(a) levels

“…Treatment of overt hyperthyroidism with thyroxine or radioactive iodine therapy increased Lp(a) concentrations by 20–25% [ 92 ]. Levothyroxine in overt and subclinical hypothyroidism slightly reduces Lp(a) levels [ 93 ].…”

Hypothyroidism and metabolic cardiovascular disease

“…OH worsens modifiable CV risk factors, inducing hypercholesterolemia, increased carotid intima-media thickness (CIMT), and reduced endothelial NO mediated relaxation ( 30 ). Low levels of THs decrease lipoprotein lipase activity in hepatic and adipose tissue, with subsequent impairment of the cholesterol metabolism that shifts in favor of increasing the circulating levels of total cholesterol and LDL-c levels ( 31 , 32 ). Taken together, all these metabolic and vascular changes contribute to the inflammation, oxidative stress, and endothelial dysfunction of the vessel walls, which therefore become more vulnerable to the development and the progression of atherosclerosis ( 33 ).…”

Lipoprotein(a)—60 Years Later—What Do We Know?

“…Lp(a) levels increase one to twofold in pregnancy and return to a normal level after delivery [10]. Treatment of overt and subclinical hypothyroidism reduces Lp(a) by 5-20% [43] while growth hormone replacement therapy causes an increase in its concentration by 25-100% [44]. Physical activity and exercise have no or minimal impact on Lp(a) [42].…”