Insulin signaling in skeletal muscle during inflammation and/or immobilisation.

BACKGROUND: The decline in the downstream signal transduction pathway of anabolic hormone, insulin, could play a key role in the muscle atrophy and insulin resistance observed in patients with intensive care unit acquired weakness (ICUAW). This study investigated the impact of immobilisation via surgical knee and ankle fixation and inflammation via Corynebacterium parvum injection, alone and in combination, as risk factors for altering insulin transduction and, therefore, their role in ICUAW. RESULTS: Muscle weight was significantly decreased due to immobilisation [estimated effect size (95% CI) - 0.10 g (- 0.12 to - 0.08); p < 0.001] or inflammation [estimated effect size (95% CI) - 0.11 g (- 0.13 to - 0.09); p < 0.001] with an additive effect of both combined (p = 0.024). pAkt was only detectable after insulin stimulation [estimated effect size (95% CI) 85.1-fold (76.2 to 94.0); p < 0.001] irrespective of the group and phosphorylation was not impaired by the different perturbations. Nevertheless, the phosphorylation of GSK3 observed in the control group after insulin stimulation was decreased in the immobilisation [estimated effect size (95% CI) - 40.2 (- 45.6 to - 34.8)] and inflammation [estimated effect size (95% CI) - 55.0 (- 60.4 to - 49.5)] groups. The expression of phosphorylated GS (pGS) was decreased after insulin stimulation in the control group and significantly increased in the immobilisation [estimated effect size (95% CI) 70.6-fold (58.8 to 82.4)] and inflammation [estimated effect size (95% CI) 96.7 (85.0 to 108.5)] groups. CONCLUSIONS: Both immobilisation and inflammation significantly induce insulin resistance, i.e., impair the insulin signaling pathway downstream of Akt causing insufficient GSK phosphorylation and, therefore, its activation which caused increased glycogen synthase phosphorylation, which could contribute to muscle atrophy of immobilisation and inflammation.

Total Disc Replacement Surgery in a Professional Australian Rugby League Player: A Case Report.

Chronic persistent lower back pain due to degenerative disc disease (DDD) of the lumbar spine is a common condition in the athletic population, which does not always improve with nonoperative treatment. We present a case report of a professional Australian rugby league player with DDD of the lumbar spine presenting with persistent lower back pain, which was not responding to conventional nonsurgical treatment. He then underwent a surgical total disc replacement of the lumbar spine and was subsequently able to return to playing professional rugby league at his previous level of competition. This is the only known documented case of a professional athlete in any form of contact sport successfully returning to his previous level of function and competition after undergoing a total disc replacement of the lumbar spine.

Depression, Anxiety, and Alcohol Use in Elite Rugby League Players Over a Competitive Season.

OBJECTIVE: To assess the prevalence of symptoms of depression, anxiety, and rates of alcohol misuse in elite rugby league players in Australasia. DESIGN: A cross-sectional, epidemiological study with repeated measures. SETTING: Surveys were conducted during the 2015 preseason and in-season. PARTICIPANTS: Four hundred four elite rugby league players participated preseason and 278 players in-season. MAIN OUTCOME MEASURES: Symptoms of depression were measured using the Patient Health Questionnaire-9 scale, symptoms of generalized anxiety disorder (GAD) with the GAD-7 scale, and the Alcohol Use Disorders Identification Test Consumption scale was used to assess hazardous alcohol use. RESULTS: The overall prevalence of depression was 12.6% preseason and 10.1% in-season. Generalized anxiety disorder had a prevalence of 14.6% and 10.1% for these 2 periods. Overall, 68.6% of players had hazardous levels of alcohol use preseason, and 62.8% in-season. There was no significant difference for any of the main outcomes between the periods. Players with a history of mental illnesses had 5.62 greater odds (95% confidence interval [CI], 2.62-12.04) of depression than those without during preseason, and 22.08 greater odds (95% CI, 7.77-62.71) in-season. Players reporting ≥3 previous concussions had 2.02 greater odds (95% CI, 1.07-3.82) of depression than those reporting ≤2 in the preseason sample. CONCLUSIONS: Rugby league players have a lower prevalence of depression compared with studies of the general population and other athletes, but a higher prevalence of GAD, and high rates of alcohol misuse. Clubs may consider implementing regular screening for these conditions. Further prospective research to determine causality of independent factors is required.

Low-intensity pulsed ultrasound in lower limb bone stress injuries: a randomized controlled trial.

OBJECTIVE: To evaluate the effectiveness of low-intensity pulsed ultrasound (LIPUS) for the improvement of lower limb bone stress injuries in a civilian population. DESIGN: A prospective, randomized, double-blinded, placebo-controlled trial to compare LIPUS with placebo. SETTING: Civilian private practice population in Sydney, Australia. PARTICIPANTS: Subjects were recruited if a grade II-IV bone stress injury was diagnosed on magnetic resonance imaging (MRI) of either the postero-medial tibia, fibula or second, third, or fourth metatarsal. Subjects of all levels of sporting activity were included. Thirty subjects were initially recruited, and 23 subjects were included in the final analysis. INTERVENTIONS: Subjects were randomized into either the treatment or placebo arm and matched to the site of injury (tibia, fibula, or metatarsal). Subjects in both arms used either treatment or placebo devices for 20 minutes daily for 4 weeks. MAIN OUTCOME MEASURES: Six clinical parameters (night pain, pain at rest, pain on walking, pain with running, tenderness, and pain with single leg hop) were compared before and after intervention. The changes in MRI grade and bone marrow edema size were also compared. RESULTS: There were no significant differences between the treatment and placebo conditions for changes in MRI grading (2.2 vs 2.4, P = 0.776) or bone marrow edema size (3 vs 4.1, P = 0.271). There were no significant differences between the treatment and placebo conditions for the 6 clinical parameters. CONCLUSIONS: Low-intensity pulsed ultrasound was found not to be an effective treatment for the healing of lower limb bone stress injuries in this study. However, this was measured over a relatively short duration of 4 weeks in a small, mostly female population. CLINICAL RELEVANCE: This double-blinded, randomized, placebo-controlled trial has shown that LIPUS is not an effective treatment for lower limb bone stress injuries.