TT3, a More Practical Indicator for Evaluating the Relationship Between Sarcopenia and Thyroid Hormone in the Euthyroid Elderly Compared with FT3.

Background and Aims: Sarcopenia is a common disease in the elderly, and the thyroid hormone (TH) might participate in the pathogenesis of sarcopenia. However, the results of previous studies were not completely consistent. We performed this study to investigate the association between THs and sarcopenia in a Chinese elderly euthyroid population. Subjects and Methods: A total of 309 Chinese elderly euthyroid subjects with an average age of 85.19 ± 7.8 years were enrolled. Participants were divided into four groups (non-sarcopenia, possible sarcopenia, sarcopenia and serve sarcopenia) according to the consensus update of AWGS in 2019. Serum levels of TT3, FT3, TT4, FT4, TSH, rT3 and TBG were measured. Muscle mass was measured by multifrequency bioelectrical impedance analysis, hand grip (HG) was represented by spring-type dynamometer, and gait speed (GS) was determined by 6-metre walk test. The FRAIL scale was used to assess frailty. Results: Compared to the non-sarcopenia group, the sarcopenia group showed a significant increase in age and FRIAL score, while FT3 and TT3 levels decreased significantly. Partial correlation analysis (adjusted by age, gender and the scores of FRIAL scale) indicated that FT3, TT3 and TSH had significant positive correlations with HG, and there also was a significant positive correlation between TT3 and GS. In addition, after adjusting for age, gender, BMI, ALT, sCr, and score on the FRAIL scale, the multivariate linear regression analysis showed that TT3 was positively associated with muscle strength and negatively associated with sarcopenia risk. Conclusion: There is an association between the low TT3 level and sarcopenia. Therefore, maintaining higher T3 concentrations within the normal range appears to be beneficial for sarcopenia in the elderly. In addition, due to the fluctuation of FT3, TT3 is a more stable and practical indicator to evaluate the relationship between sarcopenia and thyroid hormone in the elderly euthyroid population.

Chronic exposure to microcystin-LR reduces thyroid hormone levels by activating p38/MAPK and MEK/ERK signal pathway.

Microcystin-LR (MC-LR) is the most toxic and abundant microcystin that produced by cyanobacteria. Previous studies have shown MC-LR had acute toxic to thyroid, however, the mechanism is still unclear, and the effect of long-term, low-dose MC-LR on thyroid remains uncertain. In this study, we investigated the chronic, low-dose effect of MC-LR on mouse thyroid tissues and thyroid hormone metabolism. MC-LR was orally administered to mice at 0, 1, 10, 20 and 40 µg/L for 6 consecutive months for histopathological and immunoblot analysis. Nthy-ori 3-1 cells were cultured in various concentrations of MC-LR (0, 0.5, 5, 50, 500 nmol/L) for indicated time, meanwhile the cell viability and proteins change were tested. From our study, the chronic, low-dose MC-LR exposure can disturb thyroid hormone synthesis and metabolism through activating the p38/MAPK and MEK/ERK signaling pathways, then up-regulating the expression of type 3 deiodinase. These data support the potential toxic effects of MC-LR on thyroid tissue and thyroid hormone metabolism.

Association of Thyroid Function With the Estimated Glomerular Filtration Rate in a Large Chinese Euthyroid Population.

BACKGROUND/AIMS: We aimed to explore whether thyroid function within a normal range is associated with the estimated glomerular filtration rate (eGFR) and the incidence of chronic kidney disease (CKD) in a large Chinese population. METHODS: We conducted a cross-sectional study that included 10,859 euthyroid individuals who underwent an annual regular health checkup in Jiangsu Province Official Hospital between August 2012 and August 2013. We measured the thyroid-stimulating hormone (TSH), free triiodothyronine (FT3) and free thyroxine (FT4) levels using a Roche modular analytics E170 and then calculated the eGFR using the Chinese modified Modification of Diet in Renal Disease (CMDRD) equation. RESULTS: In multiple linear regression models, TSH was negatively associated with eGFR after adjusting for confounding factors (ß = -0.072, P = 1.994×10-22). The significance remained in both males and females. No significant association was observed between FT4 and eGFR. In the logistic regression model, we did not observe significant associations of TSH or FT3 with CKD. Participants in the highest quartile of FT4 versus the lowest quartile (reference) had an increased risk of CKD (OR = 1.763, P = 0.012). The risk of CKD was more pronounced in females with the highest quartile of FT4 (OR = 2.424, P = 0.029). CONCLUSION: Our findings suggest that TSH is associated with eGFR in euthyroid individuals and that higher FT4 is associated with an increased risk of CKD. More cohort studies are warranted to confirm whether the association is causal.

Situational Analysis of Low-density Lipoprotein Cholesterol Control and the Use of Statin Therapy in Diabetes Patients Treated in Community Hospitals in Nanjing, China.

BACKGROUND: Comprehensive management of diabetes should include management of its comorbid conditions, especially cardiovascular complications, which are the leading cause of morbidity and mortality among patients with diabetes. Dyslipidemia is a comorbid condition of diabetes and a risk factor for cardiovascular complications. Therefore, lipid level management is a key of managing patients with diabetes successfully. However, it is not clear that how well dyslipidemia is managed in patients with diabetes in local Chinese health-care communities. This study aimed to assess how well low-density lipoprotein cholesterol (LDL-C) was managed in Nanjing community hospitals, China. METHODS: We reviewed clinical records of 7364 diabetic patients who were treated in eleven community hospitals in Nanjing from October 2005 to October 2014. Information regarding LDL-C level, cardiovascular risk factors, and use of lipid-lowering agents were collected. RESULTS: In patients without history of cardiovascular disease (CVD), 92.1% had one or more CVD risk factors, and the most common CVD risk factor was dyslipidemia. The overall average LDL-C level was 2.80 ± 0.88 mmol/L, which was 2.62 ± 0.90 mmol/L and 2.82 ± 0.87 mmol/L in patients with and without CVD history respectively. Only 38% of all patients met the target goal and 37.3% of patients who took lipid-lowering agents met target goal. Overall, 24.5% of all patients were on lipid-lowering medication, and 36.3% of patients with a CVD history and 20.9% of patients without CVD history took statins for LDL-C management. The mean statin dosage was 13.9 ± 8.9 mg. CONCLUSIONS: Only a small portion of patients achieved target LDL-C level, and the rate of using statins to control LDL-C was low. Managing LDL-C with statins in patients with diabetes should be promoted, especially in patients without a CVD history and with one or more CVD risk factors.