Correlation among non-contractile tissue content, serum myostatin levels and functionality of chronic hemiparetics

• Grant number: 13/26370-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2014
• End date: December 31, 2014
• Field of knowledge: Health Sciences - Physiotherapy and Occupational Therapy
• Principal Investigator: Thiago Luiz de Russo
• Grantee: Thaianne Silva da Mata
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Stroke is currently the disease that most leads to disability in adults. Changes in the paretic limb muscles due to injury in the CNS result in changes in the mechanical properties of the muscles and can lead to functional deficits in these individuals. The muscle changes may be related not only to changes in contractile, but also in non-contractile tissue, especially adipose and fibrous tissue. Myostatin is a biomarker that negatively regulates skeletal muscle mass and may be related to the increase in non-contractile tissue in paretic muscle and thus, to functionality of individuals who had suffered a stroke. Objectives: To identify and correlate serum myostatin levels, the density of non-contractile tissue and functionality of gait in chronic hemiparetic subjects. Methods: 40-70 years old subjects will be recruited, of both genders, with chronic hemiparesis (> 6 months) due to unilateral ischemic or hemorrhagic origin stroke, of any hemispheres. Axial images of the quadriceps and hamstring muscles bilaterally will be obtained by Imaging Magnetic Resonance. The ROI (Region of Interest) will be obtained separately for each muscle that compose the quadriceps (rectus femoris, vastus medialis, vastus lateralis and vastus intermedius) and the hamstrings (semitendinosus / semimembranosus and biceps femoris) to measure the density of non-contractile tissue in these muscles. The density of non-contractile tissue will be obtained by MRicro software. Serum myostatin levels will be quantified by ELISA. The gait test "Timed Up and Go" (TUG) will be applied. For statistical analysis, tests for normality (Shapiro Wilk's test) and homogeneity (Levene's test) will be applied. If the variables show a normal distribution and homogenity, parametric test (Pearson correlation) will be applied. Otherwise, the nonparametric Spearman test will be used. The significance level of 5% will be considered for all tests.