coenzyme-q10 and Hypothyroidism

A low-T₃ syndrome is observed in chronic diseases, but its treatment is still debated. Chronic obstructive pulmonary disease (COPD) has not been conclusively studied under this aspect. COPD is a complex condition, which cannot be considered a lung-related disorder, but rather a systemic disease also associated to increased oxidative stress. We evaluated thyroid hormones and antioxidant systems, the lipophilic Coenzyme Q10 (CoQ₁₀) and total antioxidant capacity (TAC) in COPD patients to reveal the presence of a low-T₃ syndrome in COPD and investigate the correlation between thyroid hormones, lung function parameters and antioxidants.. We studied: 32 COPD patients and 45 controls, evaluating thyrotropin (TSH), free-triiodotyronine (fT₃), free-tetraiodotyronine (fT₄), CoQ₁₀ (also corrected for cholesterol) and TAC. CoQ₁₀ was assayed by HPLC; TAC by the metmyoglobin-ABTS method and expressed as latency time (LAG) in radical species appearance.. We found significantly lower LAG values, fT₃ and fT₄ levels and significantly higher TSH in COPD patients vs. controls. LAG values significantly correlated with fT₃ concentration. 12 out of 32 patients exhibited fT₃ levels lower than normal range. So we divided COPD patients in 2 groups on the basis of the fT₃ concentration (normal fT₃ COPD and low fT₃ COPD). We observed lower LAG values in normal fT₃-COPD, compared to healthy subjects, with a further significant reduction in low fT₃-COPD patients. Moreover higher TSH concentration was present in normal fT₃-COPD, compared to healthy subjects, with a further significant increase in low fT₃-COPD patients. CoQ₁₀/cholesterol ratio was higher in low fT₃-COPD vs. normal fT₃-COPD, with a nearly significant difference.. These data seem to indicate an increased oxidative stress in low fT₃-COPD and a role of fT₃ in modulating antioxidant systems. However low fT₃ levels are joined to metabolic indexes of true hypothyroidism, suggesting that elevated CoQ₁₀ expresses a reduced tissue utilization. These data might suggest the need of thyroid replacement therapy in such a condition.

Topics: Aged; Aged, 80 and over; Antioxidants; Cholesterol; Female; Humans; Hypothyroidism; Italy; Lung; Male; Middle Aged; Oxidative Stress; Prevalence; Pulmonary Disease, Chronic Obstructive; Regression Analysis; Thyroid Hormones; Thyrotropin; Thyroxine; Triiodothyronine; Ubiquinone

In previous works we have demonstrated plasma CoQ10 alterations in pituitary diseases, such as acromegaly or secondary hypothyroidism. However, pituitary lesions can induce complex clinical pictures due to alterations of different endocrine axes controlled by pituitary itself. A further rationale for studying CoQ10 in pituitary-adrenal diseases is related to the common biosynthetic pathway of cholesterol and ubiquinone. We have therefore assayed plasma CoQ10 levels in different conditions with increased or defective activity of pituitary-adrenal axis (3 subjects with ACTH-dependent adrenal hyperplasia, 2 cases of Cushing's disease and 1 case of 17-alpha-hydroxylase deficiency; 10 subjects with secondary hypoadrenalism, including three subjects with also secondary hypothyroidism). CoQ10 levels were significantly lower in isolated hypoadrenalism than in patients with adrenal hyperplasia and multiple pituitary deficiencies (mean +/- SEM: 0.57 +/- 0.04 vs 1.08 +/- 0.08 and 1.10 +/- 0.11 microg/ml, respectively); when corrected for cholesterol levels, the same trend was observed, but did not reach statistical significance. These preliminary data indicate that secretion of adrenal hormones is in some way related to CoQ10 levels, both in augmented and reduced conditions. However, since thyroid hormones have an important role in modulating CoQ10 levels and metabolism, when coexistent, thyroid deficiency seems to play a prevalent role in comparison with adrenal deficiency.

Topics: Adrenal Gland Diseases; Adrenal Glands; Adrenal Insufficiency; Adult; Aged; Cholesterol; Coenzymes; Female; Humans; Hydrocortisone; Hyperplasia; Hypothyroidism; Male; Middle Aged; Pituitary Diseases; Pituitary-Adrenal System; Thyroxine; Triiodothyronine; Ubiquinone

Coenzyme Q10 (CoQ10) plays an essential physiologic role in oxidative phosphorylation and its plasma and tissue concentration has been evaluated in various pathologic conditions, both endocrine and non endocrine; among the latter particularly in cardiac failure. Plasma CoQ10 determination has been reported in the literature an a useful diagnostic tool in differential diagnosis of thyroid diseases. In the present study we have evaluated CoQ10 circulating levels both in hypo- and hyperthyroidism. For this purpose plasma CoQ10, fT3-fT4 and TSH concentrations have been determined (HPLC, RIA and IRMA respectively) in a group of hypothyroid patients, hyperthyroid and control subjects. No patient was harbouring cardiovascular, metabolic or systemic disease. CoQ10 has resulted 0.97 +/- 0.46 mcg/ml in the hypothyroid group, 0.51 +/- 0.35 in hyperthyroid and 0.73 +/- 0.16 in control group, with a significative difference between first and second group only; more, the prevalence of high levels has appeared greater in hypo- towards hyperthyroid patients and that of low levels in the latter greater than in the former. Finally an inverse relation of CoQ10 with fT3 and tT3, but not with fT4 and tT4, has been shown. In conclusion, plasma CoQ10 levels have not given in this study a sharp distinction between euthyroidism on a side and hypo- and hyperthyroidism on the other, but necessity of longitudinal studies after therapy is outlined, both to know time of normalization of plasma concentrations and to verify the opportunity of exogenous administration of CoQ10 in hyperthyroid patients with risk factors for heart failure.

Topics: Adult; Coenzymes; Female; Humans; Hyperthyroidism; Hypothyroidism; Male; Middle Aged; Ubiquinone

The correlation between serum CoQ10 levels and serum thyroid hormones in thyroid disorders was investigated in the present studies. Serum CoQ10 was measured by high speed liquid chromatography utilizing ultraviolet detector. In normal controls, serum CoQ10 level of the male was higher than that of the female. Serum CoQ10 level in hyperthyroidism was significantly lower than that of euthyroid subjects. But in hypothyroidism, serum CoQ10 level did not show any significant difference from that of euthyroid subjects. Significant inverse correlations were demonstrated between log CoQ10 and log T3, log T4, log free T4, or log rT3. These data suggested abnormalities in the mitochondrial electron transport system in thyroid disorders.

Topics: Adolescent; Adult; Aged; Child; Coenzymes; Female; Humans; Hyperthyroidism; Hypothyroidism; Male; Middle Aged; Thyroid Diseases; Thyroid Hormones; Thyroidectomy; Ubiquinone