Metabolic profile and nitric oxide synthase expression of skeletal muscle fibers are altered in patients with type 1 diabetes.
We investigate muscle fiber composition, fiber-specific glycolytic and oxidative enzyme capacity and nitric oxide synthase (NOS) expression in skeletal muscle of patients with type 1 diabetes (T1D) compared to individuals with normal glucose tolerance (NGT). Vastus lateralis muscle was obtained by percutaneous biopsy from 7 T1D patients and 10 healthy controls with similar characteristics. Using cytophotometry, muscle fiber composition and fiber type-specific glycolytic and oxidative enzyme activities were measured in slow oxidative (SO), fast oxidative glycolytic (FOG) and fast glycolytic (FG) fibers. In addition, NOS 1-3 protein expression was mea-sured. The glycolytic fiber fraction was 1.4 fold higher, whereas FOG and SO fiber fractions were significantly reduced by 13.5% and 6.2% in skeletal muscle from T1D patients. Glycolytic enzyme activities and fiber-specific ratio of glycolytic relative to oxidative enzyme activity were significantly higher in all fiber types of T1D patients and correlated with HbA (1c). Expression of NOS1-3 isoforms was reduced in skeletal muscle of T1D subjects. Increased glycolytic enzyme activity in muscle of T1D patients is most likely due to both a higher number of fast glycolytic fibers and a shift towards increased glycolytic metabolism in all fiber types. Alterations in muscle fiber distribution and enzyme activities seem to be due to impaired long-term glycemic control.
Fritzsche
K
K
Institute of Anatomy, University of Leipzig, Germany.
Blüher
M
M
Schering
S
S
Buchwalow
I B
IB
Kern
M
M
Linke
A
A
Oberbach
A
A
Adams
V
V
Punkt
K
K
D000328:Adult; D001706:Biopsy; D003922:Diabetes Mellitus, Type 1 / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D005260:Female; D020869:Gene Expression Profiling; D006019:Glycolysis; D006801:Humans; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000201:enzymology* / Q000473:pathology; D018482:Muscle, Skeletal / Q000201:enzymology* / Q000473:pathology; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D010101:Oxygen Consumption; D010809:Physical Fitness; D012016:Reference Values; D044465:White People; D055815:Young Adult
C496320:NOS1 protein, human; C496319:NOS2 protein, human; C496314:NOS3 protein, human; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III