Fiber type-specific response of skeletal muscle satellite cells to high-intensity resistance training in dialysis patients.
BACKGROUND
The aim of this study was to assess the effect of high-intensity resistance training on satellite cell (SC) and myonuclear number in the muscle of patients undergoing dialysis.


METHODS
Patients (n = 21) underwent a 16-week control period, followed by 16 weeks of resistance training 3 times weekly. SC and myonuclear number were determined by immunohistochemistry of vastus lateralis muscle biopsy cross-sections. Knee extension torque was tested in a dynamometer.


RESULTS
During training, SCs/type I fibers increased by 15%, whereas SCs/type II fibers remained unchanged. Myonuclear content of type II, but not type I, fibers increased with training. Before the control period, the SC content of type II fibers was lower than that of type I fibers, whereas contents were comparable when normalized to fiber area. Torque increased after training.


CONCLUSIONS
Increased myonuclear content of type II muscle fibers of dialysis patients who perform resistance training suggests that SC dysfunction is not the limiting factor for muscle growth.
Department of Cardiology, Nephrology & Endocrinology, Nordsjaellands Hospital, Dyrehavevej 29, 3400 Hillerød, University of Copenhagen, Copenhagen, Denmark.
Stig
S
Molsted
Institute of Sports Medicine Copenhagen, Department of Orthopaedic Surgery M, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark.
Jesper Løvind
JL
Andersen
Department of Veterinary Clinical and Animal Sciences, Faculty of Health and Medical Sciences, Copenhagen University, Copenhagen, Denmark.
Adrian Paul
AP
Harrison
Department of Nephrology P, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
Inge
I
Eidemak
Institute of Sports Medicine Copenhagen, Department of Orthopaedic Surgery M, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark.
Abigail Louise
AL
Mackey
D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018656:Muscle Fibers, Fast-Twitch / Q000166:cytology* / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D011897:Random Allocation; D006435:Renal Dialysis / Q000009:adverse effects; D055070:Resistance Training / Q000379:methods*; D032496:Satellite Cells, Skeletal Muscle / Q000502:physiology*
chronic kidney disease; muscle hypertrophy; muscle strength; satellite cells; strength training