title: Intact glucose transport in morphologically altered denervated skeletal muscle from quadriplegic patients.
abstract: The present study was undertaken to investigate the nature of the whole body insulin resistance that characterizes patients with complete cervical spinal cord lesion. Nine patients with C5-C7 lesions and ten age-matched healthy individuals were studied. Whole body insulin-mediated glucose utilization was reduced by 43% in the quadriplegic patients compared with the controls (P < 0.001). In the quadriplegic patients, lean body mass corresponded to 66 +/- 3% of total body mass. Despite whole body insulin resistance, in isolated vastus lateralis muscle, basal and insulin-stimulated 3-O-methylglucose transport, as well as protein expression of the insulin or exercise-regulatable glucose transporter, GLUT-4, and glycogen content were comparable between the patients and controls. Strikingly, muscle fiber area was reduced by 44% (P < 0.05), percentage of type IIb fibers was increased (P < 0.01), and there was a complete loss of type I fibers in the patients. In conclusion, the dissociation between whole body insulin-mediated glucose uptake and skeletal muscle glucose transport in quadriplegic patients primarily reflects the decreased muscle mass. Furthermore, these findings demonstrate a remarkable capacity of skeletal muscle to maintain an intact glucose transport system despite severe morphological alterations.
authors.affiliation: Sunnaas Hospital, Nesoddtangen, Norway.
authors.forename: A K
authors.initials: AK
authors.lastname: Aksnes
authors.forename: N
authors.initials: N
authors.lastname: Hjeltnes
authors.forename: E O
authors.initials: EO
authors.lastname: Wahlström
authors.forename: A
authors.initials: A
authors.lastname: Katz
authors.forename: J R
authors.initials: JR
authors.lastname: Zierath
authors.forename: H
authors.initials: H
authors.lastname: Wallberg-Henriksson
mesh_terms: D000328:Adult; D001692:Biological Transport; D003714:Denervation; D005947:Glucose / Q000378:metabolism*; D051275:Glucose Transporter Type 4; D006801:Humans; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000378:metabolism; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000294:innervation / Q000378:metabolism*; D011782:Quadriplegia / Q000378:metabolism*
chemical_list: D051275:Glucose Transporter Type 4; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; C495692:SLC2A4 protein, human; D005947:Glucose