Magnesium Deficiency Alters Expression of Genes Critical for Muscle Magnesium Homeostasis and Physiology in Mice

Low extracellular magnesium induces phenotypic and metabolic alterations in C2C12-derived myotubes

Magnesium (Mg) has a pivotal role in upholding skeletal muscle health and optimizing performance. Its deficiency decreases muscle strength, and an association has been reported between Mg intake and sarcopenia. To gain a comprehensive understanding of the repercussions arising from low Mg concentrations on muscle behavior, we employed an in vitro model utilizing C2C12-derived myotubes. Myotubes cultured in low Mg show a significant reduction of thickness and a concomitant down-regulation of myosin heavy chain (MyHC), Myog and Myomixer. In parallel, myotubes shape their metabolism. Glycolysis is inhibited and beta-oxidation increases. These metabolic changes are consistent with the increase of MyHC I (slow) vs. MyHC II (fast) expression. We identified an essential player in these changes, namely nitric oxide (NO), as the increase in NO production appeared to orchestrate the observed modifications in myotube behavior and metabolism under low Mg conditions. Understanding these underlying mechanisms may pave the way for targeted interventions to ameliorate muscle-related conditions associated with Mg deficiency and contribute to enhancing overall muscle health and function.

Nutrition and sarcopenia: Current knowledge domain and emerging trends

Objective

Non-pharmacological management like nutrient supplements has shown positive impacts on muscle mass and strength, which has burgeoned clinical and research interest internationally. The aim of this study was to analyze the current knowledge domain and emerging trends of nutrition-related research in sarcopenia and provide implications for future research and strategies to prevent or manage sarcopenia in the context of aging societies.

Materials and methods

Nutrition- and sarcopenia-related research were obtained from the Web of Science Core Collection (WoSCC) database from its inception to April 1, 2022. Performance analysis, science mapping, and thematic clustering were performed by using the software VOSviewer and R package “bibliometrix.” Bibliometric analysis (BA) guideline was applied in this study.

Results

A total of 8,110 publications were extracted and only 7,510 (92.60%) were selected for final analysis. The production trend in nutrition and sarcopenia research was promising, and 1,357 journals, 107 countries, 6,668 institutions, and 31,289 authors were identified in this field till 2021. Stable cooperation networks have formed in the field, but they are mostly divided by region and research topics. Health and sarcopenia, metabolism and nutrition, nutrition and exercise, body compositions, and physical performance were the main search themes.

Conclusions

This study provides health providers and scholars mapped out a comprehensive basic knowledge structure in the research in the field of nutrition and sarcopenia over the past 30 years. This study could help them quickly grasp research hotspots and choose future research projects.

Magnesium Homeostasis in Myogenic Differentiation-A Focus on the Regulation of TRPM7, MagT1 and SLC41A1 Transporters

Magnesium (Mg) is essential for skeletal muscle health, but little is known about the modulation of Mg and its transporters in myogenic differentiation. Here, we show in C2C12 murine myoblasts that Mg concentration fluctuates during their differentiation to myotubes, declining early in the process and reverting to basal levels once the cells are differentiated. The level of the Mg transporter MagT1 decreases at early time points and is restored at the end of the process, suggesting a possible role in the regulation of intracellular Mg concentration. In contrast, TRPM7 is rapidly downregulated and remains undetectable in myotubes. The reduced amounts of TRPM7 and MagT1 are due to autophagy, one of the proteolytic systems activated during myogenesis and essential for the membrane fusion process. Moreover, we investigated the levels of SLC41A1, which increase once cells are differentiated, mainly through transcriptional regulation. In conclusion, myogenesis is associated with alterations of Mg homeostasis finely tuned through the modulation of MagT1, TRPM7 and SLC41A1.

Cross-Talks between the Cardiovascular Disease-Sarcopenia-Osteoporosis Triad and Magnesium in Humans

Magnesium (Mg) is a pivotal and very complex component of healthy aging in the cardiovascular-muscle-bone triad. Low Mg levels and low Mg intake are common in the general aging population and are associated with poorer outcomes than higher levels, including vascular calcification, endothelial dysfunction, osteoporosis, or muscle dysfunction/sarcopenia. While Mg supplementation appears to reverse these processes and benefit the triad, more randomized clinical trials are needed. These will allow improvement of preventive and curative strategies and propose guidelines regarding the pharmaceutical forms and the dosages and durations of treatment in order to optimize and adapt Mg prescription for healthy aging and for older vulnerable persons with comorbidities.

Editorial of Special Issue "Magnesium in Human Health and Disease"

The fundamental role of magnesium in human health is extensively discussed in the review by Fiorentini and colleagues [...].