Changes of serum cystatin C levels in patients with vascular cognitive impairment after acute stroke

Abstract

Objective To explore changes and clinical significances of serum cystatin (Cys) C levels in patients with vascular cognitive impairment (VCI) after acute stroke, in order to provide evidence for early diagnosis and treatment of patients with VCI. Methods From December 2012 to December 2013, a total of 120 cases of acute stroke patients who were treated in Department of Neurology and Neurosurgery, Dongying People's Hospital were included in this study, as study group. According to whether the patients complicated VCI or not after stroke, study group were divided into VCI subgroup (n=60) and non-VCI subgroup (n=60). And at the same period, a total of 60 cases of elderly health examination who were over 50 years old and without complaints of cognitive dysfunction were included in control group (n=60). Systematic evaluations of VCI patients' cognitive function were evaluated by mini-mental state examination (MMSE) scale, and severity of VCI was divided according to results of MMSE score. Levels of serum Cys C in three group were detected with immunoturbidimetry by automatic biochemical analyzer, and relationship between serum Cys C levels and VCI severity was analyzed. The study protocol was approved by the Ethical Review Board of Investigation in Human Being of Dongying People's Hospital. Informed consent was obtained from all participants. Results There were no significant differences in gender, age, years of education, high blood pressure, diabetes and other socio-demographic data among VCI subgroup, non-VCI subgroup and control group (P>0.05). Level of serum Cys C in VCI subgroup was (1.68±0.46) mg/L, which was higher than (0.88±0.42) mg/L of non-VCI subgroup and (0.83±0.32) mg/L of control group, and difference among three group was statistically significant (F=12.99, P<0.05). In VCI subgroup, there was statistical difference of levels of serum Cys C in patients with different VCI degrees (F=7.98, P<0.05). There were 19 cases of severe VCI patients with MMSE score ≤13 whose serum levels of Cys C were (1.92±0.36) mg/L. There were 23 cases of moderate VCI patients with MMSE score of ≥14-20 whose serum levels of Cys C were (1.33±0.41) mg/L. There were 18 cases of mild VCI patients with MMSE score of ≥21-24 whose levels of Cys C were (1.09±0.28) mg/L. There was statistical difference among above three groups (F=7.98, P<0.05). The higher levels of serum Cys C in VCI patients after acute stroke were, the more serious the degree of their VCI. The results of bivariate Spearmen correlation coefficient analysis showed that there was a negative correlation between levels of Cys C and MMSE scores in VCI patients (r=-0.421, P=0.039). Conclusions Levels of Cys C in VCI patients after acute stroke were related to their development of VCI. Levels of serum Cys C could be one of biomarkers in peripheral blood as an early diagnosis of VCI, to provide biological evidence for early diagnosis and treatment of VCI. Key words: Stroke; Cognition disorders; Diagnosis; Cystatin C