31P MR spectroscopy and in vitro markers of oxidative capacity in type 2 diabetes patients.
BACKGROUND
Skeletal muscle mitochondrial function in type 2 diabetes (T2D) is currently being studied intensively. In vivo (31)P magnetic resonance spectroscopy ((31)P MRS) is a noninvasive tool used to measure mitochondrial respiratory function (MIFU) in skeletal muscle tissue. However, microvascular co-morbidity in long-standing T2D can interfere with the (31)P MRS methodology.


OBJECTIVE
To compare (31)P MRS-derived parameters describing in vivo MIFU with an in vitro assessment of muscle respiratory capacity and muscle fiber-type composition in T2D patients.


METHODS
(31)P MRS was applied in long-standing, insulin-treated T2D patients. (31)P MRS markers of MIFU were measured in the M. vastus lateralis. Muscle biopsy samples were collected from the same muscle and analyzed for succinate dehydrogenase activity (SDH) and fiber-type distribution.


RESULTS
Several (31)P MRS parameters of MIFU showed moderate to good correlations with the percentage of type I fibers and type I fiber-specific SDH activity (Pearson's R between 0.70 and 0.75). In vivo and in vitro parameters of local mitochondrial respiration also correlated well with whole-body fitness levels (VO (2peak)) in these patients (Pearson's R between 0.62 and 0.90).


CONCLUSIONS
Good correlations exist between in vivo and in vitro measurements of MIFU in long-standing insulin-treated T2D subjects, which are qualitatively and quantitatively consistent with previous results measured in healthy subjects. This justifies the use of (31)P MRS to measure MIFU in relation to T2D.
Praet
S F E
SF
Department of Movement Sciences, Nutrition and Toxicology Research Institute Maastricht, Maastricht University, 6200, MD, Maastricht, The Netherlands. Stephan.Praet@bw.unimaas.nl
De Feyter
H M M
HM
Jonkers
R A M
RA
Nicolay
K
K
van Pul
C
C
Kuipers
H
H
van Loon
L J C
LJ
Prompers
J J
JJ
D000244:Adenosine Diphosphate / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000328:Adult; D015415:Biomarkers / Q000032:analysis; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D010759:Phosphorus Isotopes
D015415:Biomarkers; D010759:Phosphorus Isotopes; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D010100:Oxygen