JAK/STAT inhibition augments soleus muscle function in a rat model of critical illness myopathy via regulation of complement C3/3R.

KEY POINTS: Critical illness myopathy (CIM) is a frequently observed negative consequence of modern critical care. Chronic Janus kinase (JAK)/signal transducer and activator of transcription activation impairs muscle size and function and is prominent following mechanical ventilation. We identify pSTAT-3 activation in tibialis anterior of CIM patients, before examining the potential benefits of JAK1/2 inhibition in an experimental model of CIM, where muscle mass and function are impaired. CIM activates complement cascade and increased monocyte infiltration in the soleus muscle, which was ameliorated by JAK1/2 inhibition, leading to reduced muscle degeneration and improved muscle force. Here, we demonstrate that JAK1/2 inhibition augments CIM muscle function through regulation of the complement cascade. ABSTRACT: Critical illness myopathy (CIM) is frequently observed in response to modern critical care with negative consequences for patient quality of life, morbidity, mortality and healthcare costs. Janus kinase (JAK)/signal transducer and activator of transcription (STAT) activation is observed in limb muscles following controlled mechanical ventilation. Chronic JAK/STAT activation promotes loss of muscle mass and function. Thus, we hypothesized that JAK1/2 inhibition would improve muscle outcomes for CIM. Following 12 days of intensive care unit conditions, pSTAT-3 levels increased in tibialis anterior muscle of CIM patients (P = 0.0489). The potential of JAK1/2 inhibition was assessed in an experimental model of CIM, where soleus muscle size and force are impaired. JAK1/2 inhibition restores soleus force (P < 0.0001). CIM activated muscle complement cascade, which was ameliorated by JAK1/2 inhibition (P < 0.05, respectively). Soleus macrophage number corresponded with complement activity, leading to reduced muscle degeneration and augmented muscle function (P < 0.05). Thus, JAK/STAT inhibition improves soleus function by modulating the complement cascade and muscle monocyte infiltration. Collectively, we demonstrate that JAK/STAT inhibition augments muscle function in CIM.

Mechano-signalling pathways in an experimental intensive critical illness myopathy model.

KEY POINTS: Using an experimental rat intensive care unit (ICU) model, not limited by early mortality, we have previously shown that passive mechanical loading attenuates the loss of muscle mass and force-generation capacity associated with the ICU intervention. Mitochondrial dynamics have recently been shown to play a more important role in muscle atrophy than previously recognized. In this study we demonstrate that mitochondrial dynamics, as well as mitophagy, is affected by mechanosensing at the transcriptional level, and muscle changes induced by unloading are counteracted by passive mechanical loading. The recently discovered ubiquitin ligases Fbxo31 and SMART are induced by mechanical silencing, an induction that similarly is prevented by passive mechanical loading. ABSTRACT: The complete loss of mechanical stimuli of skeletal muscles, i.e. loss of external strain related to weight bearing and internal strain related to activation of contractile proteins, in mechanically ventilated, deeply sedated and/or pharmacologically paralysed intensive care unit (ICU) patients is an important factor triggering the critical illness myopathy (CIM). Using a unique experimental ICU rat model, mimicking basic ICU conditions, we have recently shown that mechanical silencing is a dominant factor triggering the preferential loss of myosin, muscle atrophy and decreased specific force in fast- and slow-twitch muscles and muscle fibres. The aim of this study is to gain improved understanding of the gene signature and molecular pathways regulating the process of mechanical activation of skeletal muscle that are affected by the ICU condition. We have focused on pathways controlling myofibrillar protein synthesis and degradation, mitochondrial homeostasis and apoptosis. We demonstrate that genes regulating mitochondrial dynamics, as well as mitophagy are induced by mechanical silencing and that these effects are counteracted by passive mechanical loading. In addition, the recently identified ubiquitin ligases Fbxo31 and SMART are induced by mechanical silencing, an induction that is reversed by passive mechanical loading. Thus, mechano-cell signalling events are identified which may play an important role for the improved clinical outcomes reported in response to the early mobilization and physical therapy in immobilized ICU patients.

The impact of e-learning during COVID-19 pandemic on students' body aches in Palestine.

Musculoskeletal pain is a major concern in our life due to its negative effects on our ability to perform daily functions. During COVID-19 pandemic, several countries switched their teaching programs into e-learning, where students spend long hour using electronic devices. The use of these devices was associated with several musculoskeletal complains among the students. The aim of this study is to evaluate the different body aches associated with e-learning on university students. The subjects of this study were students from An-Najah University in Palestine. 385 questionnaires were filled using Google forms questionnaire and all the subjects were using e-learning due to COVID-19 pandemic. Our study showed that a large percentage of participants used electronic devices for e-learning during the pandemic. The Duration of these devices use was correlated with duration and degree of pain, and associated with the difficulty in ability to perform several daily activities. Furthermore, most of the students used the sitting position with supine bent forward during the device usage. Thus, the university students that participated in this study had an increase in body aches during the e-learning process, and the aches duration and severity increases if the duration of electronic devices usage increase.

Chaperone co-inducer BGP-15 mitigates early contractile dysfunction of the soleus muscle in a rat ICU model.

AIM: Critical illness myopathy (CIM) represents a common consequence of modern intensive care, negatively impacting patient health and significantly increasing health care costs; however, there is no treatment available apart from symptomatic and supportive interventions. The chaperone co-inducer BGP-15 has previously been shown to have a positive effect on the diaphragm in rats exposed to the intensive care unit (ICU) condition. In this study, we aim to explore the effects of BGP-15 on a limb muscle (soleus muscle) in response to the ICU condition. METHODS: Sprague-Dawley rats were subjected to the ICU condition for 5, 8 and 10 days and compared with untreated sham-operated controls. RESULTS: BGP-15 significantly improved soleus muscle fibre force after 5 days exposure to the ICU condition. This improvement was associated with the protection of myosin from post-translational myosin modifications, improved mitochondrial structure/biogenesis and reduced the expression of MuRF1 and Fbxo31 E3 ligases. At longer durations (8 and 10 days), BGP-15 had no protective effect when the hallmark of CIM had become manifest, that is, preferential loss of myosin. Unrelated to the effects on skeletal muscle, BGP-15 had a strong positive effect on survival compared with untreated animals. CONCLUSIONS: BGP-15 treatment improved soleus muscle fibre and motor protein function after 5 days exposure to the ICU condition, but not at longer durations (8 and 10 days) when the preferential loss of myosin was manifest. Thus, long-term CIM interventions targeting limb muscle fibre/myosin force generation capacity need to consider both the post-translational modifications and the loss of myosin.

Toxicity of titanium dioxide nanoparticles: Effect of dose and time on biochemical disturbance, oxidative stress and genotoxicity in mice.

The toxic impact of titanium dioxide nanoparticles (TiO2NPs) on human health is of prime importance owing to their wide uses in many commercial industries. In the present study, the effect of different doses and exposure time durations of TiO2NPs (21nm) inducing oxidative stress, biochemical disturbance, histological alteration and cytogenetic aberration in mice liver and bone marrow was investigated. Different doses of (TiO2NPs) (50, 250 and 500mg/kg body weight) were each daily intrapertioneally injected to mice for 7, 14 and 45days. Aspartate and alanine aminotransferases (AST &ALT), gamma glutamyl transpeptidase (GGT), total protein, total antioxidant capacity (TAC), malondialdehyde (MDA), glutathione (GSH), catalase (CAT) and nitric oxide (NO) levels were measured. The work was extended to evaluate the liver histopathological pattern and the chromosomal aberration in mice spinal cord bone marrow. The results revealed severe TiO2NPs toxicity in a dose and time dependent manner with positive correlation (r=0.98) for most investigated biochemical parameters. The same observation was noticed for the histological analysis. In case of cytogenetic study, chromosomal aberrations were demonstrated after injection of TiO2NPs with 500mg/kg b. wt. for 45days. In conclusion, the selected biochemical parameters and the liver architectures were influenced with dose and time of TiO2NPs toxicity, while the genetic disturbance started at the high dose of exposure and for long duration. Further studies are needed to fulfil the effect of TiO2NPs on pharmaceutical and nutritional applications.

The chaperone co-inducer BGP-15 alleviates ventilation-induced diaphragm dysfunction.

Ventilation-induced diaphragm dysfunction (VIDD) is a marked decline in diaphragm function in response to mechanical ventilation, which has negative consequences for individual patients' quality of life and for the health care system, but specific treatment strategies are still lacking. We used an experimental intensive care unit (ICU) model, allowing time-resolved studies of diaphragm structure and function in response to long-term mechanical ventilation and the effects of a pharmacological intervention (the chaperone co-inducer BGP-15). The marked loss of diaphragm muscle fiber function in response to mechanical ventilation was caused by posttranslational modifications (PTMs) of myosin. In a rat model, 10 days of BGP-15 treatment greatly improved diaphragm muscle fiber function (by about 100%), although it did not reverse diaphragm atrophy. The treatment also provided protection from myosin PTMs associated with HSP72 induction and PARP-1 inhibition, resulting in improvement of mitochondrial function and content. Thus, BGP-15 may offer an intervention strategy for reducing VIDD in mechanically ventilated ICU patients.

The combined effect of sleep deprivation and Western diet on spatial learning and memory: role of BDNF and oxidative stress.

Either sleep deprivation or Western diet can impair learning and memory via induction of oxidative stress, which results in neuronal damage and interference with the neurotransmission. In this study, we examined the combined effect of sleep deprivation and Western diet on hippocampus-dependent spatial learning and memory. In addition, possible molecular targets for sleep deprivation and Western diet-induced cognitive impairments were investigated. Sleep deprivation was induced in rats using the modified multiple platform model simultaneous with the administration of Western diet for 6 weeks. Thereafter, spatial learning and memory were tested using radial arm water maze. At the molecular level, BDNF protein and antioxidant markers including superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), glutathione (GSH), oxidized glutathione (GSSG), GSH/GSSG, and thiobarbituric acid reactive substances (TBARS) were assessed. The results of this study revealed that sleep deprivation, Western diet, or a combination of both impair short- and long-term memory (P < 0.05). The magnitude of the impairment induced by the combined treatment at the 24-h long-term memory was higher than that caused by each factor alone (P < 0.05). In addition, the combined treatment reduced the levels of hippocampal BDNF, a reduction that was not detected with each factor alone. Moreover, the combined treatment reduced the hippocampal activities of SOD, catalase, GPx, ratio of GSH/GSSG, and elevated TBARS level (P < 0.05). In conclusion, the combination of sleep deprivation and Western diet decreases BDNF levels and increases oxidative stress in the hippocampus, thus inducing memory impairment that is greater than the impairment produced by each factor alone.

Vitamin E prevents high-fat high-carbohydrates diet-induced memory impairment: the role of oxidative stress.

Memory and learning are impaired by imbalanced diet consumption. High-fat high-carbohydrate diet (HFCD) induces oxidative stress, which results in neuronal damage and interference with synaptic transmission; hence, a decline in cognitive function. Vitamin E is a fat soluble antioxidant that is believed to have positive effects on learning and memory. In this study, we tested the hypothesis that chronic administration of vitamin E prevents learning and memory impairment induced by HFCD. In addition, possible molecular targets for HFCD, and vitamin E that lead to cognitive effects were examined. Vitamin E and/or HFCD were concurrently administered to animals for 6 weeks. Thereafter, behavioral studies were conducted to test the spatial learning and memory using radial arm water maze (RAWM). Additionally, brain derived neurotrophic factor (BDNF) level and antioxidant markers were assessed in the hippocampus. The results of this project revealed that HFCD impairs both short-term and long-term memories (p<0.05). The administration of vitamin E prevented the memory impairment induced by HFCD consumption (p<0.05). The consumption of HFCD reduced activities of hippocampal superoxide dismutase (SOD) and catalase (p<0.05); whereas the levels of thiobarbituric acid reactive substances (TBARS) and oxidized glutathione (GSSG) were elevated (p<0.05). The administration of vitamin E normalized the effect of HFCD on the oxidative stress markers. None of the treatments induced changes in the levels of BDNF or glutathione peroxidase (GPx). In conclusion, HFCD induces memory impairment, and the administration of vitamin E prevented this impairment probably through normalizing antioxidant mechanisms in the hippocampus.

The neuroprotective effect of vitamin E on chronic sleep deprivation-induced memory impairment: the role of oxidative stress.

Sleep deprivation induces oxidative stress and impairs learning and memory processes. Vitamin E, on the other hand, is a strong antioxidant that has neuroprotective effect on the brain. In this study, we examined the potential protective effect of chronic administration of vitamin E on chronic sleep deprivation-induced cognitive impairment. In addition, possible molecular targets for vitamin E effects on chronic sleep deprivation-induced cognitive impairment were determined. Sleep deprivation was induced in rats using modified multiple platform model. Vitamin E (100mg/kg) was administered to animals by oral gavage. Behavioral study was conducted to test the spatial learning and memory using the radial arm water maze (RAWM). In addition, the hippocampus was dissected out and antioxidant markers including glutathione (GSH), oxidized glutathione (GSSG) and GSH/GSSG, glutathione peroxidase (GPx), catalase, and superoxide dismutase (SOD) were assessed. The results of this project revealed that chronic sleep deprivation impaired both (short- and long-term) memories (P<0.05), while vitamin E treatment prevented such effect. Additionally, vitamin E normalized chronic sleep deprivation-induced reduction in the hippocampus GSH/GSSG ratio, and activity of catalase, SOD, and GPx. In conclusion, sleep deprivation induces memory impairment, and treatment with vitamin E prevented this impairment probably through its antioxidant action in the hippocampus.