Aims/hypothesis
Intramyocellular lipids, including diacylglycerol (DAG) and ceramides, have been linked to insulin resistance. This randomised repeated-measures study examined the effects of diet-induced weight loss (DIWL) and aerobic exercise (EX) o ...

Aims/hypothesis
Intramyocellular lipids, including diacylglycerol (DAG) and ceramides, have been linked to insulin resistance. This randomised repeated-measures study examined the effects of diet-induced weight loss (DIWL) and aerobic exercise (EX) on insulin sensitivity and intramyocellular triacylglycerol (IMTG), DAG and ceramide.

Methods
Sixteen overweight to obese adults (BMI 30.6 ± 0.8; 67.2 ± 4.0 years of age) with either impaired fasting glucose, or impaired glucose tolerance completed one of two lifestyle interventions: DIWL (n = 8) or EX (n = 8). Insulin sensitivity was determined using hyperinsulinaemic–euglycaemic clamps. Intramyocellular lipids were measured in muscle biopsies using histochemistry and tandem mass spectrometry.

Results
Insulin sensitivity was improved with DIWL (20.6 ± 4.7%) and EX (19.2 ± 12.9%). Body weight and body fat were decreased by both interventions, with greater decreases in DIWL compared with EX. Muscle glycogen, IMTG content and oxidative capacity were all significantly (p < 0.05) decreased with DIWL and increased with EX. There were decreases in DAG with DIWL (−12.4 ± 14.6%) and EX (−40.9 ± 12.0%). Ceramide decreased with EX (−33.7 ± 11.2%), but not with DIWL. Dihydroceramide was decreased with both interventions. Sphingosine was decreased only with EX. Changes in total DAG, total ceramides and other sphingolipids did not correlate with changes in glucose disposal. Stearoyl-coenzyme A desaturase 1 (SCD1) content was decreased with DIWL (−19.5 ± 8.5%, p < 0.05), but increased with EX (19.6 ± 7.4%, p < 0.05). Diacylglycerol acyltransferase 1 (DGAT1) was unchanged with the interventions.

Conclusions/interpretation
Diet-induced weight loss and exercise training both improved insulin resistance and decreased DAG, while only exercise decreased ceramides, despite the interventions having different effects on IMTG. These alterations may be mediated through differential changes in skeletal muscle capacity for oxidation and triacylglycerol synthesis.

Trial registration:
ClinicalTrials.gov NCT00766298

Funding:
ADA Clinical Research Award (B. H. Goodpaster), NIH R01 AG20128 (B. H. Goodpaster), Obesity and Nutrition Research (1P30DK46204) and Clinical and Translational Research Centers (UL1 RR024153)

(출처 : Springer, https://doi.org/10.1007/s00125-011-2065-0)

본 자료는 최종결과물(결과보고서)의 원자료이다.

이 자료는 지방독성과 인슐린 저항성 및 운동의 관계성에 관한 선행연구이며, 본 연구에서는 선행자료에 대한 분석을 바탕으로 실험을 진행하고 골격근내 지방독성과 염증성 사이토카인의 관련성 및 영향력에 대해 고 ...

본 자료는 최종결과물(결과보고서)의 원자료이다.

이 자료는 지방독성과 인슐린 저항성 및 운동의 관계성에 관한 선행연구이며, 본 연구에서는 선행자료에 대한 분석을 바탕으로 실험을 진행하고 골격근내 지방독성과 염증성 사이토카인의 관련성 및 영향력에 대해 고찰하고자 하였다.

Abstract
Keywords
Abbreviations

Introduction

Methods
Study participants
Study groups
Diet-induced weight loss
Aerobic exercise
Insulin sensitivity
Blood chemistry
Body composition and maximal aerobic capacity
Skeletal muscle biopsy and ...

Abstract
Keywords
Abbreviations

Introduction

Methods
Study participants
Study groups
Diet-induced weight loss
Aerobic exercise
Insulin sensitivity
Blood chemistry
Body composition and maximal aerobic capacity
Skeletal muscle biopsy and tissue analysis
Statistical analysis

Results
Study participants
Body composition and physical fitness
Insulin sensitivity
Intramyocellular lipids, oxidative capacity and glycogen content
Protein production

Discussion

References