Muscle Atrophy, Voluntary Activation Disturbances, and Low Concentrations of IGF-1 and IGFBP-3 Are Associated With Weakness in People With Chronic Stroke

You've identified the problem,
What the hell is the solution?
Don't do things only halfway.

http://ptjournal.apta.org/content/early/2014/02/26/ptj.20130322.abstract

1. Marcela de Abreu Silva-Couto (marcela.deabreu@yahoo.com.br),
2. Christiane L. Prado-Medeiros,
3. Ana Beatriz Oliveira,
4. Carolina Carmona Alcântara,
5. Araci Teixeira Guimarães,
6. Tania Fatima Salvini,
7. Rosana Mattioli and
8. Thiago Luiz Russo

+ Author Affiliations

1. M.A. Silva-Couto, Department of Physical Therapy, Federal University of São Carlos, Rodovia Washington Luis, Km 235, Monjolinho, São Carlos, São Paulo, Brazil 13565-905.
2. C.L. Prado-Medeiros, Department of Physical Therapy, Federal University of São Carlos.
3. A.B. Oliveira, Department of Physical Therapy, Federal University of São Carlos.
4. C.C. Alcântara, Department of Physical Therapy, Federal University of São Carlos.
5. A.T. Guimarães, Department of Physical Therapy, Federal University of São Carlos.
6. T.F. Salvini, Department of Physical Therapy, Federal University of São Carlos.
7. R. Mattioli, Department of Physical Therapy, Federal University of São Carlos.
8. T.L. Russo, Department of Physical Therapy, Federal University of São Carlos.

Abstract

Background and Purpose The muscle weakness that is exhibited post-stroke is due to a multifactorial etiology involving central nervous system and skeletal muscle changes. Insulin-like growth factor I (IGF-1) and IGF binding protein 3 (IGFBP-3) have been described as biomarkers of neuromuscular performance in many conditions. However, no information about these biomarkers is available for chronic hemiparetic subjects. Thus, the purpose of the present study was to investigate possible factors involved to muscle weakness in chronic post-stroke subjects, such as serum IGF-1 and IGFBP-3 concentrations, muscle volume and neuromuscular performance of knee flexors and extensors in chronic hemiparetic post-stroke subjects.

Methods A cross-sectional study was performed on 14 post-stroke subjects who were paired with healthy controls. Mobility, functionality, balance and quality of life were recorded as outcome measures. The knee flexor and extensor muscle volumes and neuromuscular performance were measured by nuclear magnetic resonance, dynamometry and electromyography. The serum concentrations of IGF-1 and IGFBP-3 were quantified by ELISA.

Results The hemiparetic group had low concentrations of serum IGF-1 (25%) and IGFBP-3 (40%); reduced muscle volume in the vastus medialis (32%), vastus intermedius (29%), biceps femoris (16%), semitendinosus and semimembranosus (12%); reduced peak torque, power and work of the knee flexors and extensors; and altered agonist and antagonist muscle activation compared to controls.

Conclusions Low serum IGF-1 and IGFBP-3 concentrations, deficits in neuromuscular performance, selective muscle atrophy, and decreased agonist muscle activation are presented in chronic post-stroke subjects.