Obesity leads to impairments in the morphology and organization of human skeletal muscle lipid droplets and mitochondrial networks, which are resolved with gastric bypass surgery-induced improvements in insulin sensitivity.

AIMS: Skeletal muscle lipid stores and mitochondrial function have been appointed as key players in obesity-induced insulin resistance. However, there are conflicting reports in the literature based on in vitro quantitative measurements. Here, we test the hypothesis that it is not the quantity but the quality that matters. METHODS: This study combines quantitative and qualitative structural measurements of lipid stores and mitochondrial dynamics in skeletal muscle from lean subjects, and subjects with morbid obesity, with and without type 2 diabetes, before and after gastric bypass surgery. RESULTS: The structural organization of muscle mitochondrial networks in type II muscle fibres from subjects with morbid obesity is impaired. In addition, the amount of skeletal muscle perilipin 2 protein per intramyocellular lipid is reduced in subjects with morbid obesity, resulting in qualitative alterations in perilipin 2 coat around some lipid droplets. Gastric bypass surgery-induced weight loss and insulin resistance remission were associated with decreases in intramyocellular lipid stores and, qualitative improvements in lipid droplets' morphology, perilipin 2 coat and mitochondrial dynamics. CONCLUSION: Morbid obesity leads to severe qualitative alterations of both skeletal muscle lipid stores and mitochondrial networks. The degree of structural improvements after gastric bypass surgery was proportional to the improvements in whole body insulin sensitivity, suggesting an association between these events.

An outbreak of enterotoxigenic Escherichia coli (ETEC) infection in Norway, 2012: a reminder to consider uncommon pathogens in outbreaks involving imported products.

We investigated an outbreak of gastroenteritis following a Christmas buffet served on 4-9 December 2012 to ~1300 hotel guests. More than 300 people were reported ill in initial interviews with hotel guests. To identify possible sources of infection we conducted a cohort investigation through which we identified 214 probable cases. Illness was associated with consumption of scrambled eggs (odds ratio 9·07, 95% confidence interval 5·20-15·84). Imported chives added fresh to the scrambled eggs were the suspected source of the outbreak but were unavailable for testing. Enterotoxigenic Escherichia coli (ETEC) infection was eventually confirmed in 40 hotel guests. This outbreak reinforces that ETEC should be considered in non-endemic countries when the clinical picture is consistent and common gastrointestinal pathogens are not found. Following this outbreak, the Norwegian Food Safety Authority recommended that imported fresh herbs should be heat-treated before use in commercial kitchens.