Serum levels of uncoupling proteins in patients with differential insulin resistance: A community-based cohort study

Sex Differences in the Relationship between Excessive Alcohol Consumption and Metabolic Abnormalities: A Community-Based Study in Taiwan

Excessive alcohol consumption, as part of an unhealthy lifestyle, can contribute to metabolic abnormalities. This study investigated the sex differences in the relationship between excessive drinking and the risk of metabolic abnormalities. This community-based study included 3387 participants (age range: 30–103 years, mean age ± SD: 57 ± 13.5 years, 38.2% males) from the northeastern region of Taiwan. All participants completed a demographic survey and were subjected to blood tests. The risks of excessive drinking were evaluated using the Alcohol Use Disorder Identification Test (AUDIT). The results showed that males were at higher risks of obesity, hypertension, and hypertriglyceridemia, but at a lower risk of abdominal obesity than females. Males with hazardous drinking were at greater risks of hypertension, hyperglycemia, low serum levels of high-density lipoprotein cholesterol, and hypertriglyceridemia compared to those with no drinking. Females with hazardous drinking were at a greater risk of hypertension than those with no drinking. There was no interaction effect of sex and excessive drinking on the risks of metabolic abnormalities after controlling for demographics and lifestyle-related habits. Future studies are warranted to explore the sex-specific risk factors for metabolic abnormalities and to elucidate the mechanism underlying this association between alcohol consumption and metabolic abnormalities.

Association of 45-bp ins/del polymorphism of uncoupling protein 2 (UCP2) and susceptibility to nonalcoholic fatty liver and type 2 diabetes mellitus in North-west of Iran

OBJECTIVE

Uncoupling protein 2 (UCP2) plays a crucial role in energy homeostasis via insulin secretion regulation, free fatty acid concentrations, and lipid metabolism. This study aimed to investigate the association of 45-bp ins/del polymorphism of UCP2 with susceptibility to NAFLD (Non-Alcoholic Fatty Liver Disease) and T2DM (Type 2 Diabetes Mellitus). DNA was extracted from the white blood cells of the subjects, and the gene polymorphism was determined using polymerase chain reaction (PCR). In this study, 72 patients with NAFLD, 71 healthy individuals as control, 80 patients with T2DM, and 77 healthy controls were enrolled in the study.

RESULTS

A higher prevalence of insertion/insertion genotype was observed in T2DM patients compared to the controls (p- value˂ 0.05). There was no difference in genotype distribution between NAFLD patients and controls (p-value > 0.05). NAFLD patients with D/D, D/I genotype had higher triglyceride, ALT, and AST levels; however, their HDL levels were lower than healthy controls. Patients with T2DM with D/D or D/I genotype also had significantly higher fasting serum glucose (FSG). While we found an association between the 45 bp I/D polymorphism in 3'UTR of UCP2 and T2DM, no correlation between this polymorphism and NAFLD was identified.

UCP2 as a Potential Biomarker for Adjunctive Metabolic Therapies in Tumor Management

Glioblastoma (GBM) remains one of the most lethal primary brain tumors in both adult and pediatric patients. Targeting tumor metabolism has emerged as a promising-targeted therapeutic strategy for GBM and characteristically resistant GBM stem-like cells (GSCs). Neoplastic cells, especially those with high proliferative potential such as GSCs, have been shown to upregulate UCP2 as a cytoprotective mechanism in response to chronic increased reactive oxygen species (ROS) exposure. This upregulation plays a central role in the induction of the highly glycolytic phenotype associated with many tumors. In addition to shifting metabolism away from oxidative phosphorylation, UCP2 has also been implicated in increased mitochondrial Ca²⁺ sequestration, apoptotic evasion, dampened immune response, and chemotherapeutic resistance. A query of the CGGA RNA-seq and the TCGA GBMLGG database demonstrated that UCP2 expression increases with increased WHO tumor-grade and is associated with much poorer prognosis across a cohort of brain tumors. UCP2 expression could potentially serve as a biomarker to stratify patients for adjunctive anti-tumor metabolic therapies, such as glycolytic inhibition alongside current standard of care, particularly in adult and pediatric gliomas. Additionally, because UCP2 correlates with tumor grade, monitoring serum protein levels in the future may allow clinicians a relatively minimally invasive marker to correlate with disease progression. Further investigation of UCP2’s role in metabolic reprogramming is warranted to fully appreciate its clinical translatability and utility.

Mitochondrial dysfunction and pancreatic islet β-cell failure (Review)

Pancreatic β-cells are the only source of insulin in humans. Mitochondria uses pyruvate to produce ATP as an intermediate link between glucose intake and insulin secretion in β-cells, in a process known as glucose-stimulated insulin secretion (GSIS). Previous studies have demonstrated that GSIS is negatively regulated by various factors in the mitochondria, including tRNA^Leu mutations, high p58 expression, reduced nicotinamide nucleotide transhydrogenase activity, abnormal levels of uncoupling proteins and reduced expression levels of transcription factors A, B1 and B2. Additionally, oxidative stress damages mitochondria and impairs antioxidant defense mechanisms, leading to the increased production of reactive oxygen species, which induces β-cell dysfunction. Inflammation in islets can also damage β-cell physiology. Inflammatory cytokines trigger the release of cytochrome c from the mitochondria via the NF-κB pathway. The present review examined the potential factors underlying mitochondrial dysfunction and their association with islet β-cell failure, which may offer novel insights regarding future strategies for the preservation of mitochondrial function and enhancement of antioxidant activity for individuals with diabetes mellitus.