Serum concentration impacts myosin heavy chain expression but not cellular respiration in human LHCN-M2 myoblasts undergoing differentiation.

NEW FINDINGS: What is the central question of this study? Does the concentration of human serum affect skeletal muscle differentiation and cellular respiration of LHCN-M2 myoblasts? What is the main finding and its importance? The concentration of serum used to differentiate LHCN-M2 skeletal muscle cells impacts the coverage of myosin heavy chain, a marker of terminally differentiated myotubes. Normalisation of mitochondrial function data to total protein negates the differences observed in absolute values, which differ as a result of increased protein content when differentiation occurs with increasing concentration of serum. ABSTRACT: The human LHCN-M2 myoblast cell line has the potential to be used to investigate skeletal muscle development and metabolism. Experiments were performed to determine how different concentrations of human serum affect myogenic differentiation and mitochondrial function of LHCN-M2 cells. LHCN-M2 myoblasts were differentiated in serum-free medium, 0.5% or 2% human serum for 5 and 10 days. Myotube formation was assessed by immunofluorescence staining of myosin heavy chain (MHC) and molecularly by mRNA expression of Myogenic differentiation 1 (MYOD1) and Myoregulatory factor 5 (MYF5). Following differentiation, mitochondrial function was assessed to establish the impact of serum concentration on mitochondrial function. Time in differentiation increased mRNA expression of MYOD1 (day 5, 6.58 ± 1.33-fold; and day 10, 4.28 ± 1.71-fold) (P = 0.012), while suppressing the expression of MYF5 (day 5, 0.21 ± 0.11-fold; and day 10, 0.06 ± 0.03-fold) (P = 0.001), regardless of the serum concentration. Higher serum concentrations increased MHC area (serum free, 11.92 ± 0.85%; 0.5%, 23.10 ± 5.82%; 2%, 43.94 ± 8.92%) (P = 0.001). Absolute basal respiration approached significance (P = 0.06) with significant differences in baseline oxygen consumption rate (P = 0.025) and proton leak (P = 0.006) when differentiated in 2% human serum, but these were not different between conditions when normalised to total protein. Our findings show that increasing concentrations of serum of LHCN-M2 skeletal muscle cells into multinucleated myotubes, but this does not affect relative mitochondrial function.

Efficacy of Vancomycin Powder in Mitigating Infection of Open Penetrating Trauma Wounds on the Battlefield: An Evidence-Based Review.

BACKGROUND: Open penetrating trauma wounds to the extremities remain the most common injuries encountered in combat and are frequently complicated by bacterial infections. These infections place a heavy burden on the Servicemember and the healthcare system as they often require multiple additional procedures and can frequently cause substantial debility. Previous studies have shown that vancomycin powder has demonstrated efficacy in decreasing infection risks in clean and contaminated orthopedic surgical wounds. METHODS: This review evaluates the most prevalent organisms cultured post-trauma, the current Tactical Combat Casualty Care (TCCC) guidelines for antibiotic prophylaxis, and relevant research of vancomycin's prophylactic use. RESULTS: Results from previous studies have shown a time-dependent reduction in bacterial load when vancomycin powder is introduced early post injury in traumatic orthopedic wounds. Furthermore, perioperative application affords a cost-effective method to prevent infection with minimal adverse effects. DISCUSSION: The current TCCC guidelines advocate for the use of antibiotics at the point of injury. When vancomycin powder is used in synergy with these guidelines, it can contribute a timely and powerful antibiotic to prevent infection. CONCLUSION: The prophylactic use of vancomycin powder is a promising adjunctive agent to current Clinical Practice Guidelines (CPG), but it cannot be conclusively determined to be effective without further research into its application in traumatic combat wounds.