Differential Relationship between Microstructural Integrity in White Matter Tracts and Motor Recovery following Stroke Based on Brain-Derived Neurotrophic Factor Genotype.

Eunhee Park,Won Hyuk Chang,Yun-Hee Kim,Friedhelm C Hummel,Ahee Lee,Jungsoo Lee

doi:10.1155/2020/5742421

Abstract

Objective The relationship between white matter integrity and the brain-derived neurotrophic factor (BDNF) genotype and its effects on motor recovery after stroke are poorly understood. We investigated the values of fractional anisotropy (FA) in the corticospinal tract (CST), the intrahemispheric connection from the primary motor cortex to the ventral premotor cortex (M1PMv), and the interhemispheric connection via the corpus callosum (CC) in patients with the BDNF genotype from the acute to the subacute phase after stroke. Methods The Fugl-Meyer assessment, upper extremity (FMA-UE), and tract-related FA were assessed at 2 weeks (T1) and 3 months (T2) after stroke using diffusion tensor imaging (DTI). Fifty-eight patients diagnosed with ischemic stroke were classified according to the BDNF genotype into a Val (valine homozygotes) or Met (methionine heterozygotes and homozygotes) group. Results The Val group exhibited a larger reduction of FA values in the ipsilesional M1PMv than the Met group from T1 to T2. The FMA-UE at T2 was negatively correlated with FA of the contralesional M1PMv at T2 in the Val group but was positively correlated with FA of the ipsilesional CST and CC at T2 in the Met group. Conclusions The integrity of the intra- and interhemispheric connections might be related to different processes of motor recovery dependent on the BDNF genotype. Thus, the BDNF genotype may need to be considered as a factor influencing neuroplasticity and functional recovery in patients with stroke. This trial is registered with http://www.clinicaltrials.gov: NCT03647787.

Highlights

Stroke is the most common cause of adult disability [1]
There were no significant differences in the distribution of sex, age, site of stroke lesion, type of stroke involvement, volume of stroke lesion (Figure 2), distribution of initial motor impairment severity, and FMA-UE scores at each time point
Our results indicate that the corticospinal tract (CST), M1PMv, and corpus callosum (CC) tracts exhibited decreased fractional anisotropy (FA) over time in both the Val homozygotes and Met allele carriers when considering the brain-derived neurotrophic factor (BDNF) genotype

Summary

Introduction

Motor impairment is a critical disability after stroke, and recovery of motor function is crucial for restoring independence in daily life [2]. Previous studies have reported several clinical factors that can be used to predict upper limb motor recovery after stroke [1,2,3,4,5,6]. One study reported that age, severity of motor impairment at baseline, and presence or absence of a response to motor evoked potential (MEP) were significant independent predictors of upper extremity motor function in patients with stroke [5]. Another study has demonstrated a proportional recovery rule for motor function [4]; it is limited by mathematical bias [7] and does not apply to all patients with stroke, especially those with severe impairment

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Results

Conclusion