title: Skeletal muscle phosphodiester content relates to body mass and glycemic control.
abstract: BACKGROUND
  Aging and insulin resistance have been related to reduced mitochondrial function and oxidative stress. Muscular phosphodiesters (PDE) are comprised of metabolites of phospholipid breakdown and may reflect membrane damage. We aimed to test the hypothesis that myocellular PDE are increased in patients with type 2 diabetes (T2D) and correlate inversely with mitochondrial ATP turnover.
  
  
  METHODS
  A Cross-sectional study in the Clinical Research Facility of an University hospital was performed. 10 nonobese middle-aged patients with T2D, 10 healthy humans matched for sex, age and physical activity index (CONm) and 18 young healthy humans (CONy) were included. Myocellular PDE and unidirectional flux through ATP synthase (fATP) were measured with (31)P magnetic resonance spectroscopy (MRS). Intramyocellular (IMCL) and hepatocellular lipid deposition (HCL) were quantified with (1)H MRS. Insulin sensitivity (Rd) was assessed from hyperinsulinemic-euglycemic clamp tests in 10 T2D, 10 CONm and 11 CONy.
  
  
  RESULTS
  During fasting, T2D and CONm had 1.5 fold greater PDE than CONy (2.8±0.2, 2.5±0.2, 1.7±0.1 mmol/l, P = 0.004). Stimulation by insulin did not affect PDE in any group. PDE correlated negatively with Rd (r = -0.552, p<0.005) and fATP (r = -0.396, p<0.05) and positively with age (r = 0.656, p<0.001) and body mass (r = 0.597, p<0.001). PDE also related positively to HbA1c (r = 0.674, p<0.001) and fasting plasma glucose (r = 0.629, p<0.001) within T2D and across all participants.
  
  
  CONCLUSIONS
  Muscular PDE concentrations associate with age, lower resting mitochondrial activity and insulin resistance, which is determined mainly by body mass and glycemia.
authors.affiliation: Institute for Clinical Diabetology, German Diabetes Center, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Szendroedi
authors.forename: Albrecht Ingo
authors.initials: AI
authors.lastname: Schmid
authors.forename: Marek
authors.initials: M
authors.lastname: Chmelik
authors.forename: Martin
authors.initials: M
authors.lastname: Krssak
authors.forename: Peter
authors.initials: P
authors.lastname: Nowotny
authors.forename: Thomas
authors.initials: T
authors.lastname: Prikoszovich
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kautzky-Willer
authors.forename: Michael
authors.initials: M
authors.lastname: Wolzt
authors.forename: Werner
authors.initials: W
authors.lastname: Waldhäusl
authors.forename: Michael
authors.initials: M
authors.lastname: Roden
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism; D001823:Body Composition / Q000502:physiology*; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism; D005215:Fasting / Q000097:blood; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism*; D010755:Organophosphates / Q000378:metabolism*
chemical_list: D001786:Blood Glucose; D010755:Organophosphates