Afferent Stimulation to Evoke Recto-colonic Reflex for Colonic Motility

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 DESCRIPTION (provided by applicant): Following spinal cord injury, the colon is unable to evacuate stools via peristaltic propulsion. Losing bowel function can cause constipation, gastro-intestinal complications, and faecal incontinence, severely impacting health and quality of life. The standard of care for individuals with neurogenic bowel involves the design of a bowel program for predictable and effective elimination of the bowels. A bowel program includes diet, fluid intake, activity, and pharmaceutical (suppository) or mechanical rectal stimulation. However, the bowel routine can require over an hour or more to evacuate the bowels and this process typically requires the assistance of a caregiver, which adds to the cost of care and reduces independence. Restoring bowel function is considered a high priority, but remains a critically unmet need requiring further development. The objective of this project is twofold: 1) To explore sensory afferent stimulation as a means of increasing colon peristalsis and 2) To train Dennis Bourbeau to become a leading independent research, restoring pelvic functions lost to spinal cord injury or other neurological disorders. We propose preclinical and translational experiments to develop and evaluate an approach to improve colonic motility. Colonic motility is quantified by the rate, direction, and pressure of coordinated peristalsis of the colon to move stools. The majority of individuals with neurogenic bowel dysfunction use digital rectal stimulation to distend the rectum and evoke an excitatory recto-colonic reflex, which increases colonic motility and loads stool into the rectum for removal. The proposed approach would substitute digital rectal stimulation with electrical rectal stimulation, using electrical stimulation of sensory (afferent) neurons of te rectum to modulate the recto-colonic reflex. Preliminary data have shown that 1) the colon responds to electrical stimulation in animals and 2) that afferent electrical stimulation modulates other pelvic reflexes to restore function, including bladder inhibition, urethral sphincter inhibiton, and bladder excitation. We hypothesize that the recto-colonic reflex can be evoked via electrical stimulation of rectal afferents and provide clinically sufficient colonic motility. This work will provide new insights for the development of a sensory afferent stimulation-based neuroprosthetic device to restore bowel function following spinal cord injury. This research is integrated with Dennis Bourbeau's career development plan with the goal of training to become a leading investigator, focusing on rehabilitative therapies for loss of pelvic functions through sensory stimulation.