Mitochondrial Oxidative Capacity In Human Skeletal Muscle: Association with Plasma Lactate Concentration

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

Jessica Cook (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: ABSTRACT Background: Metabolic disease is a growing concern for public health. Obesity and Type II Diabetes are an epidemic and a phenotype for insulin resistance in human skeletal muscle. A reduced mitochondrial function and oxidative capacity may be associated with impairments in fatty acid oxidation , which can lead to insulin resistance and metabolic dysfunction. While reductions in mitochondrial content may be a predictive variable , reductions in mitochondrial proteins and an increase in peroxisomal proteins may be contributing factors to increases in FAO and reductions in mitochondria oxidation. Furthermore , due to these reductions , a shift to anaerobic glycolysis has resulted in an increase in plasma lactate concentrations. Purpose: The purpose of this study was to determine if a reduced skeletal muscle mitochondrial oxidative capacity was due to a reduction in mitochondrial content. The main aim was to look at the association between mitochondrial protein content and plasma lactate levels. A subaim of this study was to investigate peroxisomal protein content in skeletal muscle to determine if this organelle is upregulated. Methods: This study used data from a previous Johnson & Johnson study. Premenopausal women (n=44) , over the age of 21 were recruited. These subjects were separated by BMI , non-obese [less than]30kg/m2 , obese [greater-than or equal to]30 mg/m2 and diabetic.. Following a muscle biopsy procedure , plasma lactate concentration was determined using a Coulter-Beckman clinical blood analyzer. Mitochondrial and peroxisomal protein content was determined and analyzed using Western Blot technique Results: Mitochondrial protein content , COXIV , was significantly higher in non-obese subjects compared to obese and diabetic. Peroxisomal protein content , PEX19 , was also significantly higher in diabetic subjects compared to non-obese and obese. A significant (P[less than]0.05) correlation was found between PEX19 and lactate (p[less than]0.0344). There was a significant , positive correlation between FAO and lactate in non-obese subjects (p[less than]0.0471). There was a significant difference in PMP70 protein content following a two-tailed t-test , and COXIV vs lactate following the Grubbs Test for outliers. There was no significance found between PMP70 vs lactate , COXIV vs FAO or PEX19 vs COXIV . Conclusion: Mitochondrial protein content was significantly reduced in obese and diabetic subjects with an upregulation of some peroxisomal proteins. Lactate was negatively associated with a reduced mitochondrial oxidative capacity. More research is needed to look at differences between protein content expression and the degree of adiposity.

Additional Information

Publication

Thesis

Language: English

Date: 2018

Keywords

Mitochondrial Oxidative Capacity, Lactate, Obesity

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