Abstract
Abstract
Introduction
Obstructive Sleep Apnea (OSA) has been shown to initiate a pathological cascade negatively affecting the cardiovascular system, including cerebral circulation. There is limited data on OSA effects on regional brain function, though reduced global cerebral blood flow (CBF) has been observed among patients with OSA. However, there are few precise assessments. We hypothesized that regional CBF values are altered in OSA, and that sex influences the hypothesized relationship.
Methods
Participants from the NYU Center for Brain Health cohort (n=68; 57.4% female; mean age=66.32±6.84), representing cognitively healthy volunteers with OSA (AHI4% > 5/hr) and without, from several NIA-supported studies, completed evaluations including clinical, structural & functional high-resolution arterial spin labeling 3 tesla MRI scans. Hippocampal and temporal cortex CBF was assessed at baseline and after CO2 challenge using a rebreathing protocol. Analyses were completed using one-way ANCOVA controlling for age and BMI.
Results
More men had OSA (82.8% vs 56.4%). Men without OSA showed a larger change in CBF after challenge in left (t=2.6, p=0.014) and right (t=2.4, p=0.021) hippocampus. Although the main analyses by severity level only boarded significance, pairwise comparisons indicated men with severe OSA (AHI4%>30/hr) exhibited a larger change in CBF after challenge in the hippocampus overall compared to those with mild OSA (AHI4%5–15/hr; p=0.015) and without OSA (p=0.017). Women with severe OSA showed a reduced change in CBF after challenge in the right hippocampus compared to those with mild (p=0.016), moderate (AHI4%16–29/hr; p=0.008), and without OSA (p=0.015).
Conclusion
This study suggests a possible differential effect of OSA severity and sex on regional CBF in response to a CO2 challenge, specifically in the hippocampus. Further studies will examine cognitive consequences of these sex-specific hippocampal perfusion abnormalities in OSA.
Support
NIH/NIA (1R01HL118624) Osorio, RS 07/01/13-04/30/17 Sleep Disordered Breathing in normal elderly and risk for Alzheimer’s disease (AD).NIH/NIA (R01AG056031S1) Osorio, RS 8/01/2019-7/31/2020 Sleep Aging and Risk for Alzheimer’s disease - Research Supplement to Promote Diversity in Health-Related Research