Age- and activity-related differences in the abundance of Myosin essential and regulatory light chains in human muscle

Traditional methods for phenotyping skeletal muscle (e.g., immunohistochemistry) are labor-intensive and ill-suited to multixplex analysis, i.e., assays must be performed in a series. Addressing these concerns represents a largely unmet research need but more comprehensive parallel analysis of myofibrillar proteins could advance knowledge regarding age- and activity-dependent changes in human muscle. We report a label-free, semi-automated and time efficient LC-MS proteomic workflow for phenotyping the myofibrillar proteome. Application of this workflow in old and young as well as trained and untrained human skeletal muscle yielded several novel observations that were subsequently verified by multiple reaction monitoring (MRM).We report novel data demonstrating that human ageing is associated with lesser myosin light chain 1 content and greater myosin light chain 3 content, consistent with an age-related reduction in type II muscle fibers. We also disambiguate conflicting data regarding myosin regulatory light chain, revealing that age-related changes in this protein more closely reflect physical activity status than ageing per se. This finding reinforces the need to control for physical activity levels when investigating the natural process of ageing. Taken together, our data confirm and extend knowledge regarding age- and activity-related phenotypes. In addition, the MRM transitions described here provide a methodological platform that can be fine-tuned to suite multiple research needs and thus advance myofibrillar phenotyping.

The importance of improving diet in 'Securing Scotland's Health': exploring differences in dietary intake between Scotland and England

Background: Various factors have been investigated to account for the higher premature death rates in Scotland compared to England. Higher levels of deprivation in Scotland provide a partial explanation for these differences but recent work comparing areas of the UK with similar deprivation profiles and low life expectancy has shown that this is not the only reason. One hypothesis yet to be tested adequately is differences in diet and nutrition. Objective: To conduct a comparative analysis of dietary intake between Scotland and England using pooled food purchase data from the Living Costs and Food Survey (LCFS) from 2001 to 2012 and to assess differences in equivalised income quintiles (controlling for survey year, age of household reference person, and age household reference person left full-time education). Results: Lower intakes of fruit and vegetables, oil rich fish, fibre, vitamin A, folate, vitamin C and vitamin D and higher intakes of red and processed meat, whole milk, butter, savoury snacks, confectionary, soft drinks, saturated fat and NMES (added sugar and sugar in fruit juice), sodium and alcohol were found for Scotland compared to England. Differences between Scotland and England were higher for those on lower incomes for dietary components known to be related to health outcomes. For example fruit consumption was 14g/day lower for the lowest income quintile compared to 4 g/day lower in the highest quintile for Scotland versus England. Conclusions: A poorer diet in Scotland compared to England, particularly among disadvantaged groups, is likely to be one of the reasons for excess mortality. The current evidence on the continued poor diet in Scotland, particularly in disadvantaged groups, should not be ignored. Identifying effective, culturally appropriate approaches to improve diet across the population and notably in the most deprived areas needs further investment. Funded by NHS Health Scotland. Data provided by DEFRA, ONS and the UK Data Archive.