Targeted Transcutaneous Stimulation to Restore Autonomic Cardiovascular Health in Veterans with Spinal Cord Injury

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PROJECT SUMMARY/ABSTRACT Dr. Caitlyn Katzelnick has been working with investigators in the National Center for Spinal Cord Injury (SCI) and Immobilizing Conditions at the VA Medical Center, Bronx, NY for eight years as a senior research coordinator. Along with her Primary Mentor, Dr. Wecht, Caitlyn has been studying the effects of cardiovascular, cerebrovascular and cognitive dysfunction post SCI, and the results of her Doctoral dissertation suggest that increased arterial stiffness in individuals with SCI may relate to the degree of decentralized sympathetic cardiovascular control and increased reliance on the renin-angiotensin-aldosterone system (RAAS) for maintenance of orthostatic blood pressure (BP). Recent evidence indicates that increased arterial stiffness is an independent predictor of cardiovascular disease risk, which may contribute to the heightened cardiovascular morbidity and mortality in the SCI, compared to the general population. Increased reliance on the RAAS is believed to mitigate orthostatic falls in BP and reduce the severity of symptoms reporting; however, findings in the general population link the RAAS with vascular restructuring and remodeling. Therefore, clinical intervention to stabilize and normalize BP should be a priority in hypotensive individuals with SCI. Advances in methods of neuromodulation of the spinal processes offer a non-pharmacologic approach to restore endogenous autonomic cardiovascular control and improve orthostatic BP control. Based on our present understanding of the somatovisceral integration within the spinal cord, it is plausible that transcutaneous spinal cord stimulation (TSCS) can be targeted to excite and modulate appropriate spinal autonomic circuitry to rapidly normalize orthostatic BP; however, electrode placement and stimulation parameter mapping is needed to optimize orthostatic BP control. Therefore, our primary aim is to identify an individualized map using noninvasive TSCS of the spinal autonomic circuitry that results in an increase of seated BP. Our secondary aim is to compare BP, plasma concentrations of norepinephrine, renin and aldosterone during a head-up tilt with and without optimal TSCS. This investigation will be completed at the brand- new Center of Spinal Stimulation, located at the Kessler Foundation, which is home to our VA satellite center. Dr. Katzelnick will have access to all the necessary facilities and equipment including: TSCS, electromyography (EMG) and cardiovascular. The CDA-1 will provide Dr. Katzelnick with the advanced skill training, clinical research experience, and mentorship to facilitate her growth into an independent VA investigator. Training objectives include: 1) administering and mapping TSCS; 2) gaining an understanding of EMG recordings and analysis; and 3) assaying the RAAS hormones. Dr. Katzelnick will take academic courses to advance her knowledge base in grant writing, cardiovascular physiology, statistics, biophysics and EMG. Her mentors encompass various relevant scientific backgrounds, which converge with a similar understanding of secondary consequences after a SCI. It is anticipated that these data will begin to establish a standard methodology for TSCS mapping of spinal autonomic circuits to promote restoration of cardiovascular health, and overall well-being in Veterans with immobilizing conditions. Standardized TSCS methodology will be used in future grant applications, including a CDA-2 application, to promote improved vitality and quality of life in Veterans with SCI.