The Heart and Mind Connection: Biomarkers of Cognitive Response to Exercise in Coronary Artery Disease
Year: 2017
Type: dissertation
Abstract: Introduction: Subtle deficits in verbal memory indicating early neural risk are common in patients with coronary artery disease (CAD). While exercise can improve cognition, cognitive response to exercise is heterogeneous, strongly warranting the investigation of mechanisms obstructing the cognitive benefits of exercise. This research assessed peripheral measurements of vasculopathy and sphingolipids as predictors of performance in verbal memory and other cognitive domains in CAD subjects undertaking cardiac rehabilitation (CR). Methods and Results: Cognitive performance in verbal memory (primary) and visuospatial memory, processing speed, executive function and global cognition (exploratory) was represented by standardized Z-scores in all studies. Study 1 assessed the relationship between endothelial function measured by reactive hyperemia index (RHI) using peripheral arterial tonometry and cognition at entry into and over the course of CR and explored associations with arterial stiffness measured by augmentation index (AI@75). In 64 CAD patients (mean age=63±7 years, 70% male, years of education=16±3 years), lower RHI was significantly associated with poorer verbal memory (=0.28, p=0.02) at baseline. An increase in RHI over CR was significantly associated with improved processing speed (b[SE]=0.40[0.19], p=0.04) and executive function (b[SE]=0.46[0.21], p=0.03). AI@75 was not associated with cognition at baseline or over CR. Study 2 assessed baseline plasma ceramide C22:0 and C24:0 concentrations as predictors of verbal memory over CR in a pilot study. In 33 CAD patients with CAD (mean age=62 ± 9 years, 85% male, years of education=17 ± 3 years), higher baseline plasma C22:0 (F1, 29 = 5.30, p = 0.03) and C24:0 (F1, 29 = 4.04, p = 0.05) concentrations significantly predicted less improvement in verbal memory over CR. Using a lipidomics approach, Study 3 determined associations between change in circulating sphingolipids and change in cognition over CR. In 120 CAD patients (mean age=64±6 years, 84% male, years of education=16±3 years), lower ceramide C18:0 concentrations were significantly associated with improvement in verbal memory (b[SE]=-0.51 [0.25], p=0.04), visuospatial memory (b[SE]=-0.44 [0.22], p=0.05), processing speed (b[SE]=-0.89 [0.32], p=0.007) and global cognition (b[SE]=-1.47 [0.59], p=0.01) over CR. Conclusions: Vascular health indices and plasma ceramide concentrations may be clinically useful makers of cognitive response to exercise and might provide insight into the etiology of cognitive dysfunction in patients with CAD.
Source: TSpace (University of Toronto)
Author: Mahwesh Saleem
Language: English
Subfield: Cardiology and Cardiovascular Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2810848201