Correlation of High Density Lipoproteins and Cerebral Vasomotor Reactivity in Healthy Individuals
Objective: Cerebral vasomotor reactivity (VMR) which reflects cerebrovascular autoregulation is impaired in stroke patients. Some risk factors for stroke such as hyperlipidemia affects endothelial layer of vessels and by disturbing of VMR make an important role in the occurrence of stroke. The aim of this study is the evaluation of high-density lipoproteins (HDL) effects in VMR of cerebral vessels.
Methods and Materials: Sixty healthy male volunteers (<45 years old) without vascular risk factors history were evaluated in Imam Reza Medical Center during a 12-month period. The participants were divided into three nearly equal groups with low HDL level (<40 mg/ml), normal HDL level (40-50mg/ml) and high HDL level (>40 mg/ml). The mean flow velocity of both middle cerebral arteries (MCA) continuously measured by transcranial Doppler (TCD) and VMR of MCA was calculated by breath-holding index (BHI).
Results: Mean BHI of left MCA in persons with low, normal and high HDL levels were 1.32 ± 0.44 %/sec, 1.47 ± 0.65 %/sec and 1.18 ± 0.48 %/sec respectively. Mean BHI of right MCA in low, normal and high HDL groups were 1.13 ± 0.35 %/sec, 1.39 ± 0.62 %/sec and 1.36 ± 0.55 %/sec, respectively. There was no statistically significant difference among these groups (p>0.05).
Conclusion: The current study showed that there is no statistically significant correlation between serum HDL level and BHI in left and right MCA of healthy persons.