TY - JOUR

T1 - Myosin heavy-chain isoform distribution, fibre-type composition and fibre size in skeletal muscle of patients on haemodialysis

AU - Molsted, Stig

AU - Eidemak, Inge

AU - Sorensen, Helle Tauby

AU - Kristensen, Jens Halkjaer

AU - Harrison, Adrian Paul

AU - Andersen, Jesper L.

PY - 2007

Y1 - 2007

N2 - Objective. Chronic uraemia is associated with abnormalities in skeletal muscles, which can affect their working capacity. It is also well known that the fibre-type composition of skeletal muscles influences endurance, muscle strength and power. In this study we therefore determined the size and distribution of muscle fibres and the myosin heavy-chain (MHC) isoform composition in patiens on haemodialysis (HD) in order to establish any differences with values for untrained control subjects. Material and methods. Muscle biopsies were obtained from the vastus lateralis muscle of 14 non-diabetic patients on HD. The size and distribution of muscle fibres were evaluated using adenosine triphosphate synthase (ATPase) histochemistry, whilst MHC isoform composition was determined in muscle homogenates using sodium dodecyl culphatepolyacrylamide gel electrophoresis. Values were compared to those for a group of age-, gender- and BMI-matched untrained control subjects. The aerobic work capacity of the patients was also determined. Results. The MHC composition for I, IIA and IIX isoforms was found to be 35.3%±18.2%, 35.9%±7.1% and 28.9%±15.6%, respectively, findings supported by the ATPase histochemically determined fibre-type composition of the vastus lateralis muscle. The mean fibre area of type 1 and 2 fibres was 3283±873 and 3594±1483 µm2, respectively. The MHC composition and the size of the type 1 fibres of the patients on HD were significantly different from those of the control subjects. Conclusions. The data demonstrate relatively fewer type 1 and consequently more type 2x fibres, with a corresponding change in MHC isoforms (MHC I and MHC IIX) in the skeletal muscle of patiens on HD. Several patients on HD were found to have <15% type 1 (or relative percentage of MHC I) fibres. Such a low percentage of type 1 fibres is very rarely observed in normal untrained subjects. Chronic uraemia more severely affects the composition than the size of fibres.

AB - Objective. Chronic uraemia is associated with abnormalities in skeletal muscles, which can affect their working capacity. It is also well known that the fibre-type composition of skeletal muscles influences endurance, muscle strength and power. In this study we therefore determined the size and distribution of muscle fibres and the myosin heavy-chain (MHC) isoform composition in patiens on haemodialysis (HD) in order to establish any differences with values for untrained control subjects. Material and methods. Muscle biopsies were obtained from the vastus lateralis muscle of 14 non-diabetic patients on HD. The size and distribution of muscle fibres were evaluated using adenosine triphosphate synthase (ATPase) histochemistry, whilst MHC isoform composition was determined in muscle homogenates using sodium dodecyl culphatepolyacrylamide gel electrophoresis. Values were compared to those for a group of age-, gender- and BMI-matched untrained control subjects. The aerobic work capacity of the patients was also determined. Results. The MHC composition for I, IIA and IIX isoforms was found to be 35.3%±18.2%, 35.9%±7.1% and 28.9%±15.6%, respectively, findings supported by the ATPase histochemically determined fibre-type composition of the vastus lateralis muscle. The mean fibre area of type 1 and 2 fibres was 3283±873 and 3594±1483 µm2, respectively. The MHC composition and the size of the type 1 fibres of the patients on HD were significantly different from those of the control subjects. Conclusions. The data demonstrate relatively fewer type 1 and consequently more type 2x fibres, with a corresponding change in MHC isoforms (MHC I and MHC IIX) in the skeletal muscle of patiens on HD. Several patients on HD were found to have <15% type 1 (or relative percentage of MHC I) fibres. Such a low percentage of type 1 fibres is very rarely observed in normal untrained subjects. Chronic uraemia more severely affects the composition than the size of fibres.

KW - Former LIFE faculty

KW - Fibre types

KW - haemodialysis

KW - muscle

KW - myosin heavy-chain isoform

KW - uraemia

KW - uraemic myopathy

U2 - 10.1080/00365590701421330

DO - 10.1080/00365590701421330

M3 - Journal article

C2 - 17853024

VL - 41

SP - 539

EP - 545

JO - Scandinavian Journal of Urology

JF - Scandinavian Journal of Urology

SN - 2168-1805

IS - 6

ER -