Alteration of the Intestinal Microbial Flora and the Serum IL-17 Level in Patients with Graves' Disease Complicated with Vitamin D Deficiency.

BACKGROUND: Intestinal flora is associated with Graves' disease (GD). This study explored the association of serum 25(OH)D with the diversity of the intestinal flora and serum IL-17 in GD patients. METHODS: Patients newly diagnosed with GD at 2 centers between 2018 and 2021 were consecutively included. According to their 25(OH)D levels, they were divided into the deficiency group, the insufficiency group, and the sufficiency group. Some patients with vitamin D deficiency or insufficiency were randomly selected and were matched with healthy volunteers (normal control [NC]) in terms of sex, age, and case number. The diversity and differential species of the intestinal flora and serum IL-17 levels were compared. RESULTS: Serum 25(OH)D negatively correlated with serum IL-17, the platelet/lymphocyte ratio, and TSH receptor antibody. The diversity of the intestinal flora decreased in the GD group, with noticeable differences in the composition of the intestinal flora when compared with the NC group. At the phylum level, the GD group exhibited a significantly lower abundance of Firmicutes but a higher abundance of Actinobacteria. At the genus level, the GD group exhibited higher relative abundances of Bifidobacterium, Collinsella, and Pediococcus but lower abundances of Roseburia and Dialister. CONCLUSIONS: The changes in the vitamin D level and the composition of the intestinal flora may partially contribute to the development of GD.

Dexamethasone-induced apoptosis of osteocytic and osteoblastic cells is mediated by TAK1 activation.

Increased apoptosis of osteoblasts and osteocytes is the main mechanism of glucocorticoid (GC)-induced osteonecrosis. In the current study, we investigated whether dexamethasone (Dex)-induced osteoblastic and osteocytic cell apoptosis is mediated through activation of transforming growth factor-ß (TGF-ß)-activated kinase 1 (TAK1), and whether TAK1 inhibition could promote survival opposing the deleterious effects of Dex. We found that TAK1 was activated by Dex in both osteocytic MLO-Y4 and osteoblastic OB-6 cells, which was prevented by two known anti-oxidants N-acetylcysteine (NAC) and ebselen. TAK1 inhibitors, including LYTAK1 and 5Z-7-oxozeaenol (57-OZ), inhibited Dex-induced apoptosis of MLO-Y4 and OB-6 cells. Meanwhile shRNA-mediated knockdown of TAK1 also suppressed Dex-induced damages to MLO-Y4 and OB-6 cells. On the other hand, exogenously over-expressing TAK1 enhanced Dex-induced MLO-Y4 and OB-6 cell apoptosis. At the molecular level, we found that TAK1 mediated Dex-induced pro-apoptotic Pyk2-JNK activation. Inhibition or silencing of TAK1 almost abolished Pyk2-JNK phosphorylations by Dex in MLO-Y4 and OB-6 cells. TAK1 over-expression, on the other hand, increased Dex's activity on Pyk2-JNK phosphorylations in above cells. We conclude that part of the pro-apoptotic actions of Dex on osteoblastic and osteocytic cells are mediated through TAK1 activation, and that inhibition of TAK1 might protect from GC-induced damages to osteoblasts and osteocytes.

Serum osteocalcin level and its association with carotid atherosclerosis in patients with type 2 diabetes.

OBJECTIVE: To investigate the association of serum osteocalcin with carotid atherosclerosis in patients with type 2 diabetes. METHODS: We performed a cross-sectional community-based study in metropolitan area. Serum total osteocalcin was measured by radioimmunoassay in 382 men and 435 postmenopausal women. The carotid artery intima-media thickness (IMT) and carotid plaques (PLQ) were measured by B-mode ultrasound. RESULTS: The crude mean of serum osteocalcin concentrations were 4.52±2.43 ng/ml for men and 5.75±2.92 ng/ml for postmenopausal women (P <0.001), respectively. Osteocalcin levels were associated inversely with age, fasting serum insulin, HOMA-IR, ALT, triglycerides, total cholesterol, LDL- cholesterol, CRP (all P<0.001) and positively with adiponectin and HOMA-B (all P<0.05). After multiple adjustment, the odds ratios (ORs) were substantially higher risk for carotid plaques (OR 1.77 for 1 SD decrease in osteocalcin, 95% CI 1.23-2.76, p=0.005). These associations remained significant after further adjustment for potential confounder. CONCLUSIONS: Serum osteocalcin levels is an independent risk factor for carotid atherosclerosis in patients with type 2 diabetes.