Dysregulation of mitochondrial dynamics and the muscle transcriptome in ICU patients suffering from sepsis induced multiple organ failure.

BACKGROUND: Septic patients treated in the intensive care unit (ICU) often develop multiple organ failure including persistent skeletal muscle dysfunction which results in the patient's protracted recovery process. We have demonstrated that muscle mitochondrial enzyme activities are impaired in septic ICU patients impairing cellular energy balance, which will interfere with muscle function and metabolism. Here we use detailed phenotyping and genomics to elucidate mechanisms leading to these impairments and the molecular consequences. METHODOLOGY/PRINCIPAL FINDINGS: Utilising biopsy material from seventeen patients and ten age-matched controls we demonstrate that neither mitochondrial in vivo protein synthesis nor expression of mitochondrial genes are compromised. Indeed, there was partial activation of the mitochondrial biogenesis pathway involving NRF2alpha/GABP and its target genes TFAM, TFB1M and TFB2M yet clearly this failed to maintain mitochondrial function. We therefore utilised transcript profiling and pathway analysis of ICU patient skeletal muscle to generate insight into the molecular defects driving loss of muscle function and metabolic homeostasis. Gene ontology analysis of Affymetrix analysis demonstrated substantial loss of muscle specific genes, a global oxidative stress response related to most probably cytokine signalling, altered insulin related signalling and a substantial overlap between patients and muscle wasting/inflammatory animal models. MicroRNA 21 processing appeared defective suggesting that post-transcriptional protein synthesis regulation is altered by disruption of tissue microRNA expression. Finally, we were able to demonstrate that the phenotype of skeletal muscle in ICU patients is not merely one of inactivity, it appears to be an actively remodelling tissue, influenced by several mediators, all of which may be open to manipulation with the aim to improve clinical outcome. CONCLUSIONS/SIGNIFICANCE: This first combined protein and transcriptome based analysis of human skeletal muscle obtained from septic patients demonstrated that losses of mitochondria and muscle mass are accompanied by sustained protein synthesis (anabolic process) while dysregulation of transcription programmes appears to fail to compensate for increased damage and proteolysis. Our analysis identified both validated and novel clinically tractable targets to manipulate these failing processes and pursuit of these could lead to new potential treatments.

Proteasome proteolytic activity in skeletal muscle is increased in patients with sepsis.

Patients with sepsis in the ICU (intensive care unit) are characterized by skeletal muscle wasting. This leads to muscle dysfunction that also influences the respiratory capacity, resulting in prolonged mechanical ventilation. Catabolic conditions are associated with a general activation of the ubiquitin-proteasome pathway in skeletal muscle. The aim of the present study was to measure the proteasome proteolytic activity in both respiratory and leg muscles from ICU patients with sepsis and, in addition, to assess the variation of proteasome activity between individuals and between duplicate leg muscle biopsy specimens. When compared with a control group (n=10), patients with sepsis (n=10) had a 30% (P<0.05) and 45% (P<0.05) higher proteasome activity in the respiratory and leg muscles respectively. In a second experiment, ICU patients with sepsis (n=17) had a 55% (P<0.01) higher proteasome activity in the leg muscle compared with a control group (n=10). The inter-individual scatter of proteasome activity was larger between the patients with sepsis than the controls. We also observed a substantial intra-individual difference in activity between duplicate biopsies in several of the subjects. In conclusion, the proteolytic activity of the proteasome was higher in skeletal muscle from patients with sepsis and multiple organ failure compared with healthy controls. It was shown for the first time that respiratory and leg muscles were affected similarly. Furthermore, the variation in proteasome activity between individuals was more pronounced in the ICU patients for both muscle types, whereas the intra-individual variation between biopsies was similar for ICU patients and controls.

Twelve months' follow-up after treatment with the EndoCinch endoscopic technique for gastro-oesophageal reflux disease: a randomized, placebo-controlled study.

OBJECTIVE: The Bard EndoCinch plication technique has been reported to improve symptoms and reduce oesophageal acid exposure in patients with gastro-oesophageal reflux disease (GORD). However, no placebo-controlled studies have been published as yet. The purpose of this study was to evaluate the effects of the EndoCinch plication technique in a randomized, placebo-controlled setting. MATERIAL AND METHODS: Forty-six otherwise healthy subjects with objectively verified GORD requiring regular use of proton-pump inhibitors (PPIs) were enrolled in the study. Patients were randomized to the EndoCinch plication technique or a sham procedure. Pre- and post-procedure assessments included gastro-oesophageal endoscopy, oesophageal manometry and 24-h pH recording, quality of life (QoL) assessment and use of PPIs. RESULTS: Reflux-specific symptoms and use of PPIs (total intake as well as number of patients not taking PPIs) improved in both groups at 6 weeks and at 3 and 12 months post-procedure (p<0.05) with an increased improvement in the treatment group at 3 months compared to controls (p<0.05 versus sham). There were no inter- or intra-group differences in endoscopic findings, oesophageal manometry or acid exposure before or at 3 or 12 months post-procedure. Gastro-oesophageal endoscopy showed that 71% and 67% of sutures remained at 3 and 12 months, respectively. CONCLUSIONS: Although some short-term effects were achieved, it was found that there were no differences between the treatment and control groups after 12 months and the lack of reduction of oesophageal acid exposure suggests that, in its present form, the EndoCinch plication technique is not to be recommended for use in clinical practice. It is suggested that the lack of long-term effects is primarily due to detachment of the sutures.