Cisplatin, a platinum-based drug extensively utilized in chemotherapy, is effective in treating a variety of cancer forms. Clinical studies have shown that cisplatin triggers muscle wasting and dysfunction, which significantly impacts the clinical prognosis of cancer patients. Additionally, recent research revealed that pyroptosis, a highly inflammatory cell-death, mediates muscle wasting. However, its role in cisplatin-induced skeletal muscle toxicity remains unclear. Therefore, we hypothesized that cisplatin induces myotoxicity and causes adverse skeletal muscle remodeling through pyroptosis. In this study, C57BL/6 mice (10±2 weeks old) were divided into two groups: Control(saline) and Cisplatin (cisplatin). Saline and Cisplatin were respectively administered via intraperitoneal injection (i.p.) at 2.3mg/kg body weight (BW) for 5 consecutive days (first cycle), followed by 5 days of rest, and then another 5 consecutive days (second cycle), making it a total of 10 injections and a cumulative dose of 23 mg/kg BW. At day 29 (D29), the muscle function was assessed by subjecting the mice to grip force tests and weight tests. Gastrocnemius muscle tissues from sacrificed mice were collected for histological analysis. Further analysis for protein expression of pyroptosis-associated markers (TLR4, NLRP3, Caspase-1, IL-1β, IL-18, and GSDMD) was performed using immunohistochemistry and western blotting. The stimulation of TLR4 leads to the formation of the NLRP3 inflammasome which initiates the activation of Caspase-1, Il-1β and IL-18, along with the executioner of pyroptosis, GSDMD. Our data revealed that cisplatin-treatment significantly (P

Introduction: Chronic obstructive pulmonary disease (COPD) is one of the most common chronic respiratory diseases. Impairments in exercise capacity, kinesiology and skeletal muscle function are well established in these patients. Recently presented data also suggests impairments in postural balance and increased risk of falls in patients with COPD. The aim of this study is to examine postural balance functions in a group of patients and compare the results with a control group. Methods: Twelve patients (the average age 65,6 ± 7,1, 5 women, 7 men) with COPD hospitalized at the Pulmonary Clinic at the Faculty Hospital, Prague Motol and 10 healthy control subjects (the average age 58,6 ± 5,2, 7 women, 3 men) participated in this study. Participants were measured by The Activities-specific Balance Confidence Scale (ABC) and The Balance Evaluation Systems Test (BESTest). Results: COPD patients scored significantly worse (0,0099, p < 0,05) on the ABC scale total score compared to healthy controls, 78,38 ± 21,14 for COPD versus 97,78 ± 3,88 for controls. The total score and the six subsystem categories score of the BESTest were lower in COPD patients, but not significantly, compared to controls. Conclusion: Patients with COPD showed a lower degree of balance confidence and postural balance functions....

Skeletal muscle dysfunction in chronic obstructive pulmonary disease (COPD) is a condition in which peripheral skeletal muscle undergoes myopathic changes which impair muscle function, limit physical performance, and can lead to significant disability. While the etiology of the dysfunction is unknown, this study was conducted to test the hypothesis that chronic hypoxemia leads to alterations in oxygen transport and muscle function. A primary objective was to validate elastase-induced emphysema in rats as an animal model of skeletal muscle dysfunction in COPD.Arterial blood gases were used to determine the severity of hypoxemia and sodium dodecyl sulfate- polyacrylamide gel electrophoresis was used to determine the proportions of myosin heavy chain isoforms I, IIa, IIx, and IIb. Measures of microvascular oxygenation and blood flow in the spinotrapezius muscle allowed for determination of both convective and diffusive oxygen supply to the muscle, as well as calculation of muscle oxygen consumption at rest and during electrically stimulated three-minute muscle contractions. Muscle performance measures included peak force, force-time integral, and fatigue index. Due to a presumed rat respiratory virus, which likely resulted in the control group being nearly as hypoxemic as the elastase-induced emphysema group, this study was not able to definitively test the hypothesis that chronic hypoxemia leads to both a diminished supply and demand of oxygen in skeletal muscle. Although many of the results of the present study were not statistically significant, they exhibited consistent trends over time and are likely of physiological significance. All measures of muscle performance were lower in the emphysema group. In addition, spinotrapezius muscle oxygen consumption and blood flow were lower in the emphysema group. The addition of supplemental oxygen during isolated, small-muscle mass exercise did increase the force-time integral by ~18% in both groups, suggesting that muscle work in these hypoxemic animals may be limited by oxygen supply. Thus, the data on muscle fiber type, oxygen consumption and muscle performance suggest that elastase-induced emphysema in rats leads to a similar skeletal muscle dysfunction that is observed in humans with COPD, and indicates that it is a valid animal model of skeletal muscle dysfunction in COPD.

Background About half of heart failure (HF) patients, while having preserved left ventricular function, suffer from diastolic dysfunction (so-called HFpEF). No specific therapeutics are available for HFpEF in contrast to HF where reduced ejection fractions (HFrEF) can be treated pharmacologically. Myocardial titin filament stiffening, endothelial dysfunction, and skeletal muscle (SKM) myopathy are suspected to contribute to HFpEF genesis. We previously described small molecules interfering with MuRF1 target recognition thereby attenuating SKM myopathy and dysfunction in HFrEF animal models. The aim of the present study was to test the efficacy of one small molecule (MyoMed-205) in HFpEF and to describe molecular changes elicited by MyoMed-205. - Methods Twenty-week-old female obese ZSF1 rats received the MuRF1 inhibitor MyoMed-205 for 12 weeks; a comparison was made to age-matched untreated ZSF1-lean (healthy) and obese rats as controls. LV (left ventricle) unction was assessed by echocardiography and by invasive haemodynamic measurements until week 32. At week 32, SKM and endothelial functions were measured and tissues collected for molecular analyses. Proteome-wide analysis followed by WBs and RT-PCR was applied to identify specific genes and affected molecular pathways. MuRF1 knockout mice (MuRF1-KO) SKM tissues were included to validate MuRF1-specificity. - Results By week 32, untreated obese rats had normal LV ejection fraction but augmented E/e′ ratios and increased end diastolic pressure and myocardial fibrosis, all typical features of HFpEF. Furthermore, SKM myopathy (both atrophy and force loss) and endothelial dysfunction were detected. In contrast, MyoMed-205 treated rats had markedly improved diastolic function, less myocardial fibrosis, reduced SKM myopathy, and increased SKM function. SKM extracts from MyoMed-205 treated rats had reduced MuRF1 content and lowered total muscle protein ubiquitination. In addition, proteomic profiling identified eight proteins to respond specifically to MyoMed-205 treatment. Five out of these eight proteins are involved in mitochondrial metabolism, dynamics, or autophagy. Consistent with the mitochondria being a MyoMed-205 target, the synthesis of mitochondrial respiratory chain complexes I + II was increased in treated rats. MuRF1-KO SKM controls also had elevated mitochondrial complex I and II activities, also suggesting mitochondrial activity regulation by MuRF1. - Conclusions MyoMed-205 improved myocardial diastolic function and prevented SKM atrophy/function in the ZSF1 animal model of HFpEF. Mechanistically, SKM benefited from an attenuated ubiquitin proteasome system and augmented synthesis/activity of proteins of the mitochondrial respiratory chain while the myocardium seemed to benefit from reduced titin modifications and fibrosis.