The effects of treatment on lipoprotein subfractions evaluated by polyacrylamide gel electrophoresis in patients with autoimmune hypothyroidism and hyperthyroidism

THE RELATIONSHIP BETWEEN TSH LEVELS, THYROID AUTOANTIBODIES AND ATHEROGENIC INDEX OF PLASMA, AST TO PLATELET RATIO INDEX SCORE, AND FIBROSIS 4 INDEX IN PATIENTS WITH HYPOTHYROIDISM

Context

Thyroid hormones have metabolic effects such as relationship between hypothyroidism and atherosclerosis.

Objective

Evaluate the effects of hypothyroidism on Non-Alcoholic Fatty Liver Disease and atherosclerosis by using AIP, APRI score, FIB-4 indices.

Material and Methods

1370 patients with hypothyroidism who applied to the Endocrinology and Metabolism outpatient clinic between 01.01.2017-30.12.2021 were included the study. Pregnants, patients with a history of thyroid carcinoma, cardiovascular and liver diseases were excluded. TSH, fT4, Anti TPO, Anti TG, thrombocyte, ALT, AST, HDL, Triglyceride values of the cases were analyzed and atherogenic index of plasma (AIP), AST to Platelet Ratio Index (APRI) and Fibrosis-4 (FIB-4) indices were calculated.

Results

1170 (85.4%) of the cases were female.The age of those who had high risk of AIP was found to be higher than those with low and moderate risk (p=0.001; p=0.003; p<0.01). The ages of those who had low-risk FIB-4 Index were found to be lower than those with moderate risk and high risk (p=0.001; p=0.001; p<0.01). A positive relationship was detected between APRI and FIB-4 (r=0.681; p=0.001; p<0.01).AIP increased as TSH increased in hypothyroid patients. No significant correlations were detected between TSH, APRI, and the FIB-4 Index. No significant differences were detected between AIP, APRI, FIB-4, and thyroid autoantibodies.

Conclusion

In hypothyroid patients, the AIP index increased with age and the increase in TSH. A strong relationship was detected between AIP and TSH . For this reason, we think that keeping TSH within the normal range with regular follow-ups and treatment in patients with hypothyroidism will reduce the risk of atherosclerosis.

Prospective Analysis of Lipid Variations in Hyperthyroid Subjects from Lahore, Pakistan

Perturbations in the actions of T3 and T4 influence the normal metabolic pathways. Responsiveness of lipid biomarkers like LDL-C, HDL-C, TC, TG, Apo-A, and Apo-B after rehabilitation of thyroid profile attaining euthyroid state was determined. A total of 179 age-matched subjects of both genders were recruited for this research. Sixty healthy controls, thirty-four subclinical, fifty overt hyperthyroid, and thirty-five follow-up subjects having 3 months of Carbimazole therapy were enrolled. Biochemical analysis was performed by chemistry analyzer, RIA, and ELISA. One-way ANOVA was applied for the statistical analysis, while significance (P < 0.05) of means was compared by the Student-Newman-Keuls (SNK) test. Pronounced reduction (P < 0.001) of cholesterol in overt as compared to control and subclinical was noticed, whereas marked improvement (P < 0.001) was evidenced in follow-up. Prominent elevation (P < 0.05) of TG in follow-up was evidenced as compared to control. Overt presented marked reduction of HDL-C as compared to subclinical and control (P < 0.01 and P < 0.001), respectively. Pronounced elevation (P < 0.001) of HDL-C was evidenced after treatment. Overt presented reduction of LDL-C as compared to subclinical and control (P < 0.01 and P < 0.05, respectively). The follow-up group demonstrated considerable (P < 0.001) improvement of LDL-C after treatment and elevation (P < 0.05) as compared to control. Overt presented reduction of Apo-B as compared to subclinical and control (P < 0.05 and P < 0.001, respectively). Improvement (P < 0.05) of Apo-B was evidenced in follow-up. Reduction (P < 0.05) of Apo-A in overt as compared to control and elevation (P < 0.05) in follow-up as compared to overt was evidenced. Conclusively, improvement after treatment was evidenced in lipid profile.

Relation of Gut Microbes and L-Thyroxine Through Altered Thyroxine Metabolism in Subclinical Hypothyroidism Subjects

Thyroxine metabolism is an important topic of pathogenesis research and treatment schedule of subclinical hypothyroidism (SCH). L-Thyroxine replacement therapy (LRT) is usually recommended for severe SCH patients only. Our previous studies reported that disordered serum lipid of mild SCH people could also benefit from LRT. However, the benefits were different among individuals, as shown by the variations in drug dosage that required to maintain thyroid-stimulating hormone (TSH) stability. Alternative pathways, such as sulfation and glucuronidation of iodothyronine, may play a role in thyroid hormones metabolism in peripheral tissues aside from thyroid. Conjugated thyroxine can be hydrolyzed and reused in tissues including gastrointestinal tract, in which gut microbiota are one of the most attractive physiological components. On this site, the roles of gut microbiota in thyroidal metabolism should be valued. In this study, a cross-sectional study was performed by analyzing 16S rDNA of gut microbiota in mild SCH patients treated with L-thyroxine or not. Subjects were divided by serum lipid level, L-thyroxine treatment, or L-thyroxine dosage, respectively. Relationship between gut microbiome and serum profile, L-thyroxine treatment, and dose were discussed. Other metabolic disorders such as type 2 diabetes and hypertension were also taken into consideration. It turned out that microbiome varied among individuals divided by dose and the increment of L-thyroxine but not by serum lipid profile. Relative abundance of certain species that were associated with thyroxine metabolism were found varied among different L-thyroxine doses although in relatively low abundance. Moreover, serum cholesterol may perform relevance effects with L-thyroxine in shaping microbiome. Our findings suggested that the differences in L-thyroxine dosage required to maintain TSH level stability, as well as the SCH development, which was displayed by the increased L-thyroxine doses in subsequent follow-up, had relationship with gut microbial composition. The reason may due to the differences in thyroxine metabolic capacity in gut. In addition, the metabolic similarity of iodothyronines and bile acid in gut also provides possibilities for the correlation between host's thyroxine and cholesterol levels. This study was registered with ClinicalTrials.gov as number NCT01848171.

Hashimoto Thyroiditis and Dyslipidemia in Childhood: A Review

Hashimoto autoimmune thyroiditis (AIT) is the most common cause of acquired hypothyroidism in the pediatric population. Development of AIT is mediated mainly by cellular immune response directed toward thyroid autoantigens, leading to inflammation and impaired function of thyroid gland. Both thyroid dysfunction and inflammation affect the metabolism of plasma lipoproteins. The alterations in lipid profile worsen with the advancement of hypothyroidism, ranging from discrete changes in euthyroid AIT patients, to atherogenic dyslipidemia in the overt hypothyroidism. In this review, characteristics of dyslipidemia in pediatric AIT patients, and the consequences in respect to the risk for cardiovascular disease (CVD) development are discussed. Additionally, benefit of L-thyroxine treatment on serum lipid profile in pediatric AIT patients is addressed. Finally, potential usefulness of novel lipid biomarkers, such as proprotein convertase subtilisin/kexin type 9 (PCSK9), non-cholesterol sterols, low-density lipoprotein particle size and number, and high-density lipoprotein structure and functionality in AIT patients is also covered. Further longitudinal studies are needed in order to elucidate the long-term cardiovascular outcomes of dyslipidemia in pediatric patients with Hashimoto AIT.

A Worthy Finding: Decrease in Total Cholesterol and Low-Density Lipoprotein Cholesterol in Treated Mild Subclinical Hypothyroidism

BACKGROUND

Mild subclinical hypothyroidism (SCH) affects a large number of people and is known to be a risk factor for dyslipidemia. However, whether mild SCH patients should be treated with L-thyroxine to improve lipid profiles remains controversial. In addition, it is also unclear whether all mild SCH patients can benefit from L-thyroxine treatment, regardless of basal thyrotropin or lipid levels. This study aimed to assess the effects of L-thyroxine replacement therapy on the lipid profiles of mild SCH patients.

METHODS

This open-label randomized controlled trial was performed in Ningyang County, Shandong Province, China. A total of 378 mild SCH patients with diagnoses confirmed by two thyroid function tests were randomly assigned to either the intervention group (L-thyroxine replacement therapy) or the control group (no treatment). The primary outcome was a change in serum total cholesterol (TC) concentration.

RESULTS

In all, 369 participants completed the 15-month follow-up period. Reduced TC concentrations were more prominent in the intervention group than they were in the control group (-0.41 mmol/L vs. -0.17 mmol/L; p = 0.012), and changes in low-density lipoprotein cholesterol levels exhibited the same trend. Subgroup analyses were performed to assess the effects of L-thyroxine in patients with different thyrotropin or TC levels. When the study population was stratified according to basal thyrotropin concentration, all patients who had received L-thyroxine showed reduced TC levels (p < 0.001). The treatment was similarly beneficial for all patients, regardless of basal TC level. Even for subjects with TC levels <5.18 mmol/L, serum TC concentrations remained unchanged in the intervention group (p = 0.936) but increased by 0.35 mmol/L in the control group (p = 0.004).

CONCLUSIONS

The findings suggest that mild SCH patients could benefit from L-thyroxine treatment to improve lipid profiles, regardless of basal thyrotropin or TC concentrations.

Effect of short term aerobic exercise on fasting and postprandial lipoprotein subfractions in healthy sedentary men

Background

Our goal was to investigate the effect of short term exercise on fasting and postprandial lipoprotein profile.

Methods

Healthy sedentary men exercised 20 min for four days. The intensity of exercise was modulated to maintain 75–80 % of a calculated HRmax. Before and after the exercise program, fasting and postprandial (4 h after standard meal) concentrations of lipoprotein subfractions were measured by an electrophoresis in polyacrylamide gel and total concentrations of TAG, LDL and HDL by enzymatic colorimetric method. After 2 days of rest, fasting and postprandial concentrations of lipoprotein fractions and subfractions were measured to determine a persistency of a changes in the lipoprotein profile.

Results

4 days of physical exercise led to statistically significant decrease of concentration of triacylglycerol in fasting (76.29 ± 20.07, 53.92 ± 10.90, p < 0.05) and postprandial state (139.06 ± 23.72, 96.55 ± 25.21, p < 0.05) VLDL in fasting (21.88 ± 3.87, 18.00 ± 3.93, p < 0.05) and postprandial state (23.88 ± 3.52, 19.25 ± 3.62, p < 0.05), total cholesterol in fasting (162.26 ± 23.38, 148.91 ± 17.72, p < 0.05) and postprandial state (163.73 ± 23.02, 150.08 ± 18.11, p < 0.05). Atherogenic medium LDL decreased also in fasting (9.89 ± 3.27, 6.22 ± 2.55, p < 0.001) and postprandial state (8.88 ± 6.51, 6.88 ± 5.57, p < 0.001). However decrease of large IDL (25.38 ± 3.54, 23.88 ± 3.91, p < 0.05) and large LDL particles (42.89 ± 11.40, 38.67 ± 9.30) was observed only in postprandial state. Total HDL concentration remained unchanged but we observed statistically significant decrease of small HDL particles in fasting (6.11 ± 2.89, 4.22, p < 0.05) and postprandial state (6.44 ± 3.21, 4.56 ± 1.33, p < 0.05). Concentration of these particles are associated with progression of atherosclerosis. All changes of fasting and postprandial lipoprotein profile disappeared after 2 days of rest.

Conclusion

Just 4 daily settings of 20 min of physical exercise can lead to significant positive changes of fasting and postprandial lipoprotein profile.