Mitochondrial capacity is affected by glycemic status in young untrained women with type 1 diabetes but is not impaired relative to healthy untrained women

Flurin Item, Susanne Heinzer-Schweizer, Michael Wyss, Piero Fontana, Roger Lehmann, Anke Henning, Markus Weber, Peter Boesiger, Urs Boutellier, Marco Toigo

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

In this study, we examined whether glycemic status influences aerobic function in women with type 1 diabetes and whether aerobic function is reduced relative to healthy women. To this end, we compared several factors determining aerobic function of 29 young sedentary asymptomatic women (CON) with 9 women of similar age and activity level with type 1 diabetes [DIA, HbA1c range = 6.9-8.2%]. Calf muscle mitochondrial capacity was estimated by 31P-magnetic resonance spectroscopy. Capillarization and muscle fiber oxidative enzyme activity were assessed from vastus lateralis and soleus muscle biopsies. Oxygen uptake and cardiac output were evaluated by ergospirometry and N2O/SF6 rebreathing. Calf muscle mitochondrial capacity was not different between CON and DIA, as indicated by the identical calculated maximal rates of oxidative ATP synthesis [0.0307 (0.0070) vs. 0.0309 (0.0058) s=1, P = 0.930]. Notably, HbA1c was negatively correlated with mitochondrial capacity in DIA (R2 = 0.475, P = 0.040). Although HbA1c was negatively correlated with cardiac output (R2 = 0.742, P = 0.013) in DIA, there was no difference between CON and DIA in maximal oxygen consumption [2.17 (0.34) vs. 2.21 (0.32) l/min, P = 0.764], cardiac output [12.1 (1.9) vs. 12.3 (1.8) l/min, P = 0.783], and endurance capacity [532 (212) vs. 471 (119) s, P = 0.475]. There was also no difference between the two groups either in the oxidative enzyme activity or capillary-to-fiber ratio. We conclude that mitochondrial capacity depends on HbA1c in untrained women with type 1 diabetes but is not reduced relative to untrained healthy women.

Original languageEnglish (US)
Pages (from-to)R60-R66
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume301
Issue number1
DOIs
StatePublished - Jul 1 2011
Externally publishedYes

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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