Combined resveratrol and vitamin D treatment ameliorate inflammation-related liver fibrosis, ER stress, and apoptosis in a high-fructose diet/streptozotocin-induced T2DM model

The roles of dietary polyphenols at crosstalk between type 2 diabetes and Alzheimer's disease in ameliorating oxidative stress and mitochondrial dysfunction via PI3K/Akt signaling pathways

Alzheimer's disease (AD) is a fatal neurodegenerative disease in which senile plaques and neurofibrillary tangles are crucially involved in its physiological and pathophysiological processes. Growing animal and clinical studies have suggested that AD is also comorbid with some metabolic diseases, including type 2 diabetes mellitus (T2DM), and therefore, it is often considered brain diabetes. AD and T2DM share multiple molecular and biochemical mechanisms, including impaired insulin signaling, oxidative stress, gut microbiota dysbiosis, and mitochondrial dysfunction. In this review article, we mainly introduce oxidative stress and mitochondrial dysfunction and explain their role and the underlying molecular mechanism in T2DM and AD pathogenesis; then, according to the current literature, we comprehensively evaluate the possibility of regulating oxidative homeostasis and mitochondrial function as therapeutics against AD. Furthermore, considering dietary polyphenols' antioxidative and antidiabetic properties, the strategies for applying them as potential therapeutical interventions in patients with AD symptoms are assessed.

Resveratrol inhibits calcium oxalate crystal growth, reduces adhesion to renal cells and induces crystal internalization into the cells, but promotes crystal aggregation

Resveratrol is a natural phenolic compound that belongs to stilbenoid group found in diverse plants. Health benefits and therapeutic potentials of resveratrol have been widely recognized in various diseases. In kidney stone disease, it can alleviate oxalate-induced hyperproduction of free radicals in renal epithelial cells. Nevertheless, its direct effects on calcium oxalate (CaOx) crystal, which is the major stone component, remained unclear. This study therefore addressed the direct effects of resveratrol (at 1, 10 or 100 μM) on each step of CaOx kidney stone formation. The results revealed that resveratrol had no significant effects on CaOx crystallization. However, resveratrol significantly decreased CaOx crystal growth and adhesion to renal epithelial cells at all concentrations, and induced crystal internalization into the cells (a process related to crystal degradation by endolysosomes) in a concentration-dependent manner. On the other hand, resveratrol promoted crystal aggregation. These data indicate that resveratrol serves as a dual modulator on CaOx stone formation. While it inhibits CaOx stone development by reducing crystal growth and adhesion to renal cells and by inducing crystal internalization into the cells, resveratrol promotes crystal aggregation, which is one of the mechanisms leading to kidney stone formation.

Vitamin D Alleviates Type 2 Diabetes Mellitus by Mitigating Oxidative Stress-Induced Pancreatic β-Cell Impairment

OBJECTIVE

Type 2 diabetes mellitus (T2DM) is a common metabolic disorder with rising incidence worldwide. This study explored the anti-T2DM role of vitamin D, thereby providing novel therapeutic strategies.

METHODS

C57BL/6 J mice and MIN6 cells were used to induce in vivo T2DM and damaged β-cell models, respectively. Body weights, fasting blood glucose, and fasting insulin were measured in mice. Oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) were conducted on mice. Lipid indices (TG, TC, LDL-C, and HDL-C) were detected in mouse serum. Hematoxylin-eosin staining was used to evaluate pancreatic tissue injury. ELISA was used to assess insulin and oxidative stress (OS) markers (MDA, GSH, and SOD) in mice and MIN6 cells. Production of ROS was detected in islet β-cells and MIN6 cells. Cell viability and apoptosis were evaluated using CCK-8 and flow cytometry, respectively. QRT-PCR and western blotting were used to detect pro-inflammatory factors (TNF-α and IL-6) and endoplasmic reticulum stress (ERS) markers (CHOP and GRP78), respectively.

RESULTS

Vitamin D reduced body weights, fasting blood glucose, and insulin and ameliorated glucose tolerance and insulin sensitivity in T2DM mice. Besides, vitamin D decreased serum TG, TC, LDL-C, and increased HDL-C in T2DM mice. Vitamin D inhibited pancreatic histopathological injury, cell apoptosis, OS, and β-cell decline in T2DM mice. Moreover, vitamin D alleviated cell death, insufficient insulin secretion, inflammation, OS, and ERS in damaged MIN6 cells. Notably, N-acetyl-L-cysteine (an OS inhibitor) enhanced these effects of vitamin D.

CONCLUSIONS

Vitamin D relieved T2DM symptoms by alleviating OS-induced β-cell impairment.