Abstract
Background The muscle weakness that is exhibited poststroke is due to a multifactorial etiology involving the central nervous system and skeletal muscle changes. Insulinlike growth factor 1 (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 people with chronic hemiparesis.
Objective The purpose of this study was to investigate possible factors involved in muscle weakness, such as IGF-1 and IGFBP-3 serum concentrations, muscle volume, and neuromuscular performance of the knee flexors and extensors, in people with chronic hemiparesis poststroke.
Design This was a cross-sectional study.
Methods A cross-sectional study was performed on 14 individuals poststroke who were paired with healthy controls. Mobility, function, balance, and quality of life were recorded as outcome measures. Knee flexor and extensor muscle volumes and neuromuscular performance were measured using nuclear magnetic resonance imaging, dynamometry, and electromyography. The serum concentrations of IGF-1 and IGFBP-3 were quantified by enzyme-linked immunosorbent assay (ELISA).
Results The hemiparetic group had low serum concentrations of IGF-1 (25%) and IGFBP-3 (40%); reduced muscle volume in the vastus medialis (32%), vastus intermedius (29%), biceps femoris (16%), and semitendinosus and semimembranosus (12%) muscles; reduced peak torque, power, and work of the knee flexors and extensors; and altered agonist and antagonist muscle activation compared with controls.
Conclusions Low serum concentrations of IGF-1 and IGFBP-3, deficits in neuromuscular performance, selective muscle atrophy, and decreased agonist muscle activation were found in the group with chronic hemiparesis poststroke. Both hemorrhagic and ischemic stroke were considered, and the data reflect a chronic poststroke population with good function.
Footnotes
Ms Silva-Couto, Professor Prado-Medeiros, Professor Oliveira, Ms Alcântara, Professor Salvini, and Professor Russo provided concept/idea/research design. Ms Silva-Couto, Professor Prado-Medeiros, and Professor Russo provided writing. Ms Silva-Couto, Professor Prado-Medeiros, Ms Alcântara, and Ms Guimarães provided data collection. Ms Silva-Couto, Professor Prado-Medeiros, Professor Oliveira, Ms Guimarães, and Professor Russo provided data analysis. Ms Silva-Couto, Professor Prado-Medeiros, Ms Alcântara, and Professor Salvini provided project management. Ms Silva-Couto and Professor Russo provided fund procurement. Ms Silva-Couto, Professor Prado-Medeiros, and Ms Alcântara provided study participants. Professor Salvini and Professor Mattioli provided facilities/equipment and institutional liaisons. Professor Prado-Medeiros, Professor Oliveira, Professor Salvini, and Professor Mattioli provided consultation (including review of manuscript before submission).
The authors are grateful to Teresa Piassi, Fernando Vasilceac, Stela Márcia Mattielo, Tatiana de Oliveira Sato, and Centro Integrado de Diagnóstico por Imagem de São Carlos (CIDI) for their technical support.
This project was funded by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) (process numbers 2011/02703-3 and 2011/11228-7) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). Ms Silva-Couto and Ms Alcantara are master's grant holders, and Professor Prado-Medeiros is a postdoctoral grant holder supported by CNPq.
- Received July 19, 2013.
- Accepted February 24, 2014.
- © 2014 American Physical Therapy Association
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