Intermittent fasting (IF) increases lifespan and decreases metabolic disease phenotypes and cancer risk in model organisms, but the health benefits of IF in humans are less clear. Human plasma derived Show more
Intermittent fasting (IF) increases lifespan and decreases metabolic disease phenotypes and cancer risk in model organisms, but the health benefits of IF in humans are less clear. Human plasma derived from clinical trials is one of the most difficult sample sets to analyze using mass spectrometry-based proteomics due to the extensive sample preparation required and the need to process many samples to achieve statistical significance. Here, we describe an optimized and accessible device (Spin96) to accommodate up to 96 StageTips, a widely used sample preparation medium enabling efficient and consistent processing of samples prior to LC-MS/MS. We have applied this device to the analysis of human plasma from a clinical trial of IF. In this longitudinal study employing 8-weeks IF, we identified significant abundance differences induced by the IF intervention, including increased apolipoprotein A4 (APOA4) and decreased apolipoprotein C2 (APOC2) and C3 (APOC3). These changes correlated with a significant decrease in plasma triglycerides after the IF intervention. Given that these proteins have a role in regulating apolipoprotein particle metabolism, we propose that IF had a positive effect on lipid metabolism through modulation of HDL particle size and function. In addition, we applied a novel human protein variant database to detect common protein variants across the participants. We show that consistent detection of clinically relevant peptides derived from both alleles of many proteins is possible, including some that are associated with human metabolic phenotypes. Together, these findings illustrate the power of accessible workflows for proteomics analysis of clinical samples to yield significant biological insight. Show less
Obesity is commonly associated with high rates of cardiovascular disease (CVD). Weight loss in obese subjects reduces risk factors for CVD but this response is not uniform. Genetic factors could be in Show more
Obesity is commonly associated with high rates of cardiovascular disease (CVD). Weight loss in obese subjects reduces risk factors for CVD but this response is not uniform. Genetic factors could be involved in this variability. The 360His polymorphism of apolipoproteinA-IV (apoA-IV) influences the lipid response to fat intake, but it is unclear whether this polymorphism could contribute to lipid variability during weight loss. Therefore, we assessed the effects of an energy restricted diet (6.3 MJ) for 12 weeks on weight loss and plasma lipids according to apoA-IV genotype in 186 overweight/obese subjects (BMI mean 33+/-4.3, range 25.0-48.0 kg/m(2)). The frequency of the 360His allele was 0.083. Energy restriction for 12 weeks resulted in an average weight loss of 8. 25+/-0.28 kg. HDL-C increased 5.4% in subjects with the apoA-IV-1/1 genotype with weight loss compared to a 2.6% decrease in apoA-IV-1/2 subjects (P=0.035). This was more apparent when only the subjects with type 2 diabetes (n=57) were analyzed (P=0.003). ApoA-IV genotype was not related to change in total cholesterol, LDL-C or triglyceride concentrations. Therefore, weight loss as a treatment to reduce CVD risk factors may be more effective in subjects with the apoA-IV-1/1 variant as compared to those with the apoA-IV-1/2 variant, especially in subjects with type 2 diabetes. Show less