Brain-Derived Neurotrophic Factor (BDNF) Val66met (rs6265) Polymorphism Associated with Global and Multi-Domain Cognitive Impairment in Ischemic Stroke Patients

Abstract

It is suggested that brain-derived neurotrophic factor (BDNF) has a protective role against brain lesion after an ischemic stroke (IS); however, there is inadequate information as to the role of BDNF in cognitive impairments following IS. This study evaluate the effects of IS and BDNF (Val66Met) gene polymorphism on global and multi-domain (attention, memory, verbal fluency, language, and visuospatial abilities) cognitive functions. In a case-control study, we selected 206 patients with IS who were consecutively discharged from Poursina Hospital in the north of Iran. The patients were compared with the control group comprised of 200 individuals who were referred to the Social Service Retirees Center in Rasht City. The comparison was made in terms of genetic variant BDNF Val66Met and also their scores in the Addenbrooke’s Cognitive Examination-Third Edition (ACE-III). The patients compared with the control group were suffering from higher rates of global cognitive impairment. [F (1398) = 38.29, ή 2 = 0.09, P < 0.0001] and lower scores in domains of memory [F (1383) = 39.57, ή 2 = 0.094, P < 0.0001], language abilities [F (1383) = 27.05, ή 2 = 0.066, P < 0.0001], and visuospatial functions [F (1.383) = 9.54, ή 2 = 0.024, P = 0.002]. In addition, carriers of at least one Val allele were suffering from greater rates of global cognitive impairment than Met/Met homozygous [F (1398) = 12.41, ή 2 = 0.03, P < 0.0001], and their scores in the domains of attention [F (1383) = 13.43, ή 2 = 0.034, P < 0.0001] and language abilities were found to be lower than that of the control group [F (1383) = 11.73, ή 2 = 0.03, P = 0.001]. However, the interactive effects of BDNF Val66Met × groups were not statistically significant (P > 0.05). The impairments are especially evident in domains of memory, language abilities, and visuospatial functions. Furthermore, there exists a relationship between the presence of at least one BDNF Val allele and impairment in the global cognitive functions, attention, and language domains. Nonetheless, BDNF Val66Met polymorphism does not seem to have a role in any specific cognitive impairment in IS patients.