EGLP-1 lowers body weight better than exendin-4 by reducing food intake and increasing basal energy expenditure in diet-induced obese mice

The Effects of Glucagon-Like Peptide-1 Receptor Agonists on Mitochondrial Function Within Skeletal Muscle: A Systematic Review

BACKGROUND

Obesity is a chronic disease associated with increased risk of multiple metabolic and mental health-related comorbidities. Recent advances in obesity pharmacotherapy, particularly with glucagon-like peptide-1 (GLP-1) receptor agonists (RAs), have the potential to transform obesity and type 2 diabetes mellitus (T2DM) care by promoting marked weight loss, improving glycaemic control and addressing multiple obesity-related comorbidities, with added cardio-renal benefits. Dual agonists combining GLP-1 with other enteropancreatic hormones such as glucose-dependent insulinotropic polypeptide (GIP) have also been developed in recent years, leading to greater weight loss than using GLP-1 RAs alone. However, up to 40% of the weight lost with GLP-1 RAs comes from lean body mass, raising concerns about potential adverse effects on skeletal muscle function. Mitochondrial dysfunction, characterized by reduced mitochondrial size and activity, is prevalent in individuals with obesity and T2DM and is a known contributor to muscle wasting in ageing and some chronic diseases. This systematic review investigates the impact of GLP-1-based therapies on skeletal muscle mitochondrial function in individuals with obesity and T2DM or in related animal and cell models.

METHODS

A comprehensive search of MEDLINE, Scopus, CINAHL and clinicaltrials.gov was conducted. Inclusion criteria included randomized controlled trials, randomized crossover trials, cluster randomized control trials and basic science studies involving any GLP-1 RA or GLP-1/GIP dual agonist. Outcomes of interest were skeletal muscle respiratory function either in the form of measurements of mass, number, content, oxidative capacity/respiratory function, mitochondrial dynamics, mitochondrial biogenesis and mitophagy.

RESULTS

Eight studies were eligible for analysis; no human studies were identified. All of the included studies used GLP-1 RAs (single agonists) as intervention. The emerging evidence suggests that GLP-1 RAs increase mitochondrial area, number and morphology (i.e., reduces swelling). Data are conflicting on the effect of GLP-1 RAs upon mitochondrial mass, respiration and the expression of uncoupling proteins and PGC-1α. Data also demonstrate muscle specific (i.e., soleus vs. extensor digitorum longus) responses to GLP-1 RAs.

CONCLUSION

GLP-1 RAs appear to have a positive effect upon mitochondria area, number and morphology, but effects upon other aspects of mitochondrial health remain inconclusive. Data are very limited and solely presented in animal and in vitro models. Future studies should be conducted in human populations in order to begin to understand the effect of GLP-1 RAs and GLP-1-based therapies on human skeletal muscle mitochondria.

A bioinformatic analysis of WFDC2 (HE4) expression in high grade serous ovarian cancer reveals tumor-specific changes in metabolic and extracellular matrix gene expression

Human epididymis protein-4 (HE4/WFDC2) has been well-studied as an ovarian cancer clinical biomarker. To improve our understanding of its functional role in high grade serous ovarian cancer, we determined transcriptomic differences between ovarian tumors with high- versus low-WFDC2 mRNA levels in The Cancer Genome Atlas dataset. High-WFDC2 transcript levels were significantly associated with reduced survival in stage III/IV serous ovarian cancer patients. Differential expression and correlation analyses revealed secretory leukocyte peptidase inhibitor (SLPI/WFDC4) as the gene most positively correlated with WFDC2, while A kinase anchor protein-12 was most negatively correlated. WFDC2 and SLPI were strongly correlated across many cancers. Gene ontology analysis revealed enrichment of oxidative phosphorylation in differentially expressed genes associated with high-WFDC2 levels, while extracellular matrix organization was enriched among genes associated with low-WFDC2 levels. Immune cell subsets found to be positively correlated with WFDC2 levels were B cells and plasmacytoid dendritic cells, while neutrophils and endothelial cells were negatively correlated with WFDC2. Results were compared with DepMap cell culture gene expression data. Gene ontology analysis of k-means clustering revealed that genes associated with low-WFDC2 were also enriched in extracellular matrix and adhesion categories, while high-WFDC2 genes were enriched in epithelial cell proliferation and peptidase activity. These results support previous findings regarding the effect of HE4/WFDC2 on ovarian cancer pathogenesis in cell lines and mouse models, while adding another layer of complexity to its potential functions in ovarian tumor tissue. Further experimental explorations of these findings in the context of the tumor microenvironment are merited.