Dr. Thomas Nowak
University Hospital, Suite 1634
550 University Blvd
Indianapolis IN 46202-5250
Phone: (317) 948-4272
Thomas Nowak is a member of the Department of Gastorenterology and Hepatology and Professor of Clinical Medicine at the Indiana University School of Medicine. His research focuses on the mechanisms of gastric emptying in animal models of experimental diabetes and in human subjects with gastroparesis. His in vitro studies have demonstrated deficient cholinergic enteric neuromuscular transmission in the streptozotocin-treated rodent, while subsequent investigations examined the mechanism of gastric emptying in congenitally diabetic rodents as well as animals that had undergone pancreas transplantation. His recent investigations examine the efficacy of gastric electrical stimulation in the treatment of nausea and vomiting in patients with diabetic and idiopathic gastroparesis.
For the last several years he has collaborated with investigators at the Center for Implantable Devices at Purdue University in translational studies which examine the effects of gastric electrical stimulation on vagus nerve compound action potentials. Studies in anesthetized rodents show that electrical stimulation of the antrum elicits compounds action potentials as measured with cuff electrodes placed around the cervical portions of the right and left vagus nerves. Complimentary studies with human patients with gastroparesis show that similar compound action potentials can be recorded during gastric electrical stimulation with cutaneous electrodes overlying the right and left vagus nerves. These studies also show that there appears to be a significant correlation between activation of specific nerve fiber subtypes and resolution of nausea and vomiting in these patients.
Complimentary studies are planned in both rodents and human subjects which examine the effect of gastric electrical stimulation on compound action potentials in the vagus nerve. Experiments in anesthetized rodents will determine the optimal anatomic site in the stomach that allows optimal generation of vagal nerve compound action potentials as well as the optimal stimulation parameters. Using this information studies are planned in human subjects with symptomatic gastroparesis that determine whether cutaneous vagal nerve compound action potentials recorded during gastric electrical stimulation can be reliably used to regulate symptoms of nausea and vomiting. Likewise, information from the animal studies will determine what paramaters of electrical stimulation should be used and ultimately will comment on the anatomic placement of electrodes in the human stomach.
- McCallum, R.W., Snape, W., Brody, F., Wo, J., Parkman, H.P. and Nowak, T.V. (2010). Gastric electrical stimulation with Enterra therapy improves symptoms from diabetic patients in a prospective study. Clin Gastroenterol Hepatol, 8, 947-954.
- Nowak, T., Hutchins, G., Hammond, J., Wang, Y., Ring, L. and Leal, K. (2006). Effect of gastric electrical stimulation on cerebral blood flow in patients with gastroparesis. Neurogastroenterology & Motility, 18(6), 481.
- Abell, T., Hocking, M., McCallum, R., Koch, K., Abrahamsson, H., LeBlanc, I., Lindberg, G., Konturek, J., Nowak, T.V., Quigley, E., Tougas, G. and Starkebaum, W. (2003). Gastric electrical stimulation for medically refractory gastroparesis. Gastroenterology, 125, 421-428.
- Ward, M.P., Nowak, T.V., Irazoqui, P.P., Wo, J.M., Arafat, M.A. and Qing, K.Y. (2015). Gastric electrical stimulation of the antrum evokes compound cervical vagal nerve action potentials in rodents. Gastroenterology, 148(4), S-507.
- Wo JM, Nowak TV, Waseem S, Ward MP. (2016) Gastric Electrical Stimulation for Gastroparesis and Chronic Unexplained Nausea and Vomiting. Curr Treat Options Gastroenterol. Dec 14(4):386-400. Review. PubMed PMID: 27678506.
- Ward, M.P., Nowak, T.V., Wo, J., Gupta, A. and Irazoqui, P. Cutaneous vagal nerve action potentials are associated with resolution of nausea and vomiting in gastroparetic patients during gastric electrical stimulation. Gastroenterology, 2016.