Investigating the Influence of dietary restriction and omega-3 fatty acid supplementation on lifespan and sarcopenia in C. elegans

Sarcopenia is an age-related condition defined by a progressive loss of muscle mass and strength over time. It is currently recognized as one of the major public health problems in the elderly populations worldwide with people over the age of 65 experiencing some form or symptoms of sarcopenia. Despite the ever-increasing prevalence of sarcopenia, the underlying mechanism behind sarcopenia is still an area of ongoing research. Intervention studies incorporating dietary supplementation and resistance training have been shown to limit muscle function decline. The resulting need to understand and alleviate the problems associated with sarcopenia has led to an increased use of animal models, including the nematode Caenorhabditis elegans which also undergoes sarcopenia with ageing.

The main aim of this thesis was to study the potential effect of Dietary Restriction and Omega3 PUFA supplements on sarcopenia and to quantify sarcopenia rates using a novel fluorescence technique. Using an internal standard for quantification, a transgenic C. elegansstrain (unc-54:gfp) expressing GFP in one of its muscle myosin isoforms (MHC B) was utilised to measure myosin density throughout its lifespan. C. elegans treated with different regimens of DR showed that lifespan increased significantly under a mildly restricted diet, consistent with the findings in previous studies. Healthspan was also significantly improved, as indicated by a delay in the age-related decrease in motility and reduction in sarcopenia rates.Additionally, long-term algae-oil supplementation resulted in significantly lower rates of sarcopenia and a corresponding increase in motility and lifespan. It has been proposed that the microbiota regulates skeletal muscle growth and function via a gut-muscle axis. In this study, algae-oil supplementation delayed the onset of sarcopenia with reduced decline of muscle density, which correlated with delayed onset of age-related intestinal barrier dysfunction. These results support the hypothesis of an association between microbiota and sarcopenia (gut-muscle axis), indicating a novel role for algae-oil whose clinical relevance should be investigated in future studies.