Synbiotic approach restores intestinal homeostasis and prolongs survival in leukaemia mice with cachexia

Cancer cachexia is a multifactorial syndrome that includes muscle wasting and inflammation. As gut microbes influence host immunity and metabolism, we investigated the role of the gut microbiota in the therapeutic management of cancer and associated cachexia. A community-wide analysis of the caecal microbiome in two mouse models of cancer cachexia (acute leukaemia or subcutaneous transplantation of colon cancer cells) identified common microbial signatures, including decreased Lactobacillus spp. and increased Enterobacteriaceae and Parabacteroides goldsteinii/ASF 519. Building on this information, we administered a synbiotic containing inulin-type fructans and live Lactobacillus reuteri 100-23 to leukaemic mice. This treatment restored the Lactobacillus population and reduced the Enterobacteriaceae levels. It also reduced hepatic cancer cell proliferation, muscle wasting and morbidity, and prolonged survival. Administration of the synbiotic was associated with restoration of the expression of antimicrobial proteins controlling intestinal barrier function and gut immunity markers, but did not impact the portal metabolomics imprinting of energy demand. In summary, this study provided evidence that the development of cancer outside the gut can impact intestinal homeostasis and the gut microbial ecosystem and that a synbiotic intervention, by targeting some alterations of the gut microbiota, confers benefits to the host, prolonging survival and reducing cancer proliferation and cachexia

A Position Effect on the Heritability of Epigenetic Silencing

In animals and yeast, position effects have been well documented. In animals, the best example of this process is Position Effect Variegation (PEV) in Drosophila melanogaster. In PEV, when genes are moved into close proximity to constitutive heterochromatin, their expression can become unstable, resulting in variegated patches of gene expression. This process is regulated by a variety of proteins implicated in both chromatin remodeling and RNAi-based silencing. A similar phenomenon is observed when transgenes are inserted into heterochromatic regions in fission yeast. In contrast, there are few examples of position effects in plants, and there are no documented examples in either plants or animals for positions that are associated with the reversal of previously established silenced states. MuDR transposons in maize can be heritably silenced by a naturally occurring rearranged version of MuDR. This element, Muk, produces a long hairpin RNA molecule that can trigger DNA methylation and heritable silencing of one or many MuDR elements. In most cases, MuDR elements remain inactive even after Muk segregates away. Thus, Muk-induced silencing involves a directed and heritable change in gene activity in the absence of changes in DNA sequence. Using classical genetic analysis, we have identified an exceptional position at which MuDR element silencing is unstable. Muk effectively silences the MuDR element at this position. However, after Muk is segregated away, element activity is restored. This restoration is accompanied by a reversal of DNA methylation. To our knowledge, this is the first documented example of a position effect that is associated with the reversal of epigenetic silencing. This observation suggests that there are cis-acting sequences that alter the propensity of an epigenetically silenced gene to remain inactive. This raises the interesting possibility that an important feature of local chromatin environments may be the capacity to erase previously established epigenetic marks

Potential cellular and biochemical mechanisms of exercise and physical activity on the ageing process

Exercise in young adults has been consistently shown to improve various aspects of physiological and psychological health but we are now realising the potential benefits of exercise with advancing age. Specifically, exercise improves cardiovascular, musculoskeletal, and metabolic health through reductions in oxidative stress, chronic low-grade inflammation and modulating cellular processes within a variety of tissues. In this this chapter we will discuss the effects of acute and chronic exercise on these processes and conditions in an ageing population, and how physical activity affects our vasculature, skeletal muscle function, our immune system, and cardiometabolic risk in older adults

Crosstalk between autophagy and oxidative stress regulates proteolysis in the diaphragm during mechanical ventilation.

Mechanical ventilation (MV) results in the rapid development of ventilator-induced diaphragm dysfunction (VIDD). While the mechanisms responsible for VIDD are not fully understood, recent data reveal that prolonged MV activates autophagy in the diaphragm, which may occur as a result of increased cellular reactive oxygen species (ROS) production. Therefore, we tested the hypothesis that (1) accelerated autophagy is a key contributor to VIDD; and that (2) oxidative stress is required to increase the expression of autophagy genes in the diaphragm. Our findings reveal that targeted inhibition of autophagy in the rat diaphragm prevented MV-induced muscle atrophy and contractile dysfunction. Attenuation of VIDD in these animals occurred as a result of increased diaphragm concentration of the antioxidant catalase and reduced mitochondrial ROS emission, which corresponded to reductions in the activity of calpain and caspase-3. To determine if increased ROS production is required for the upregulation of autophagy biomarkers in the diaphragm, rats that were administered the mitochondrial-targeted peptide SS-31 during MV. Results from this study demonstrated that mitochondrial ROS production in the diaphragm during MV is required for the increased expression of key autophagy genes (i.e. LC3, Atg7, Atg12, Beclin1 and p62), as well as for increased activity of cathepsin L. Together, these data reveal that autophagy is required for VIDD, and that autophagy inhibition reduces MV-induced diaphragm ROS production and prevents a positive feedback loop whereby increased autophagy is stimulated by oxidative stress, resulting in further increases in ROS and autophagy

Recent developments in the field of cachexia, sarcopenia, and muscle wasting: highlights from the 11th Cachexia Conference

Abstract This article highlights the updates from preclinical and clinical studies into the field of wasting disorders that were presented at the 11th Cachexia Conference held in Maastricht, the Netherlands, in December 2018. Herein, we summarize the biological and clinical significance of different markers and new diagnostic tools and cut‐offs for the detection of skeletal muscle wasting, including micro‐RNAs, siRNAs, epigenetic targets, the ubiquitin–proteasome system, mammalian target of rapamycin signalling, news in body composition analysis including the D3‐creatine dilution method, and electrocardiography that was modified to enable segmental impedance spectroscopy. Of particular interest were the beneficial effects of BIO101 on muscle cell differentiation, hypertrophy of myofibers associated with mammalian target of rapamycin pathways activation, and the effect of metal ion transporter ZIP14 loss that reduces cancer‐induced cachexia. The potential of anti‐ZIP14 antibodies and zinc chelation as anti‐cachexia therapy should be tested in patients with cancer cachexia. Big randomized studies were presented such as RePOWER (observational study of patients with primary mitochondrial myopathy), STRAMBO (influence of physical performance assessed as score and clinical testing), MMPOWER (treatment of elamipretide in subjects with primary mitochondrial myopathy), FORCE (examined differences in relative dose intensity and moderate and severe chemotherapy‐associated toxicities between a strength training intervention and a control group), and SPRINTT (effectiveness of exercise training in healthy aging). Effective treatments were urothelin A, rapamycin analogue treatment, epigenetic factor BRD 4 and epigenetic protein BET, and the gut pathobiont Klebsiella oxytoca. Clinical studies that investigated novel approaches, including urolithin A, the role of gut microbiota, metal ion transporter ZIP14, lysophosphatidylcholine and lysophosphatidylethanolamine, and BIO101, were described. It remains a fact, however, that effective treatments of cachexia and wasting disorders are urgently needed in order to improve patients' quality of life and their survival

Recent developments in the field of cachexia, sarcopenia, and muscle wasting: highlights from the 12th Cachexia Conference

Abstract This article highlights preclinical and clinical studies in the field of wasting disorders that were presented at the 12th Cachexia Conference held in Berlin, Germany, in December 2019. Herein, we summarize the biological and clinical significance of different strategies including antibodies that target Fn14, Spsb 1, SAA1 treatment, ZIP14, a MuRF1 inhibitor, and new diagnostic tools like T‐cell communication targets and cut‐offs for the detection of skeletal muscle wasting. Of particular interest were the transplantation of mesenchymal stromal cells and muscle stem cell communication. Importantly, one presentation discussed the effect of metal ion transporter ZIP14 loss that reduces cancer‐induced cachexia. The potential of anti‐ZIP14 antibodies and zinc chelation as anti‐cachexia therapy may require testing in patients with cancer cachexia. Large clinical studies were presented such as RePOWER (observational study of patients with primary mitochondrial myopathy), MMPOWER (treatment with elamipretide in patients with primary mitochondrial myopathy), and ACT‐ONE as well as new mouse models like the KPP mouse. Promising treatments include rapamycin analogue treatment, anamorelin, elanapril, glucocorticoids, SAA1, antibodies that target Fn14, and a MuRF1 inhibitor. Clinical studies investigated novel approaches, including the role of exercise. It remains a fact, however, that effective treatments for cachexia and wasting disorders are urgently needed in order to improve patients' quality of life and their survival