Metabolic endpoints for obstructive sleep apnea following twelfth cranial nerve stimulation (MET12)

The National Heart, Lung, and Blood Institute awarded the University of Pennsylvania $254,026 on September 30, 2025, under the Cardiovascular Diseases Research program (CFDA 93.837) to support Dr. Nathan Nowalk's postdoctoral research training in metabolic endpoints for obstructive sleep apnea following hypoglossal nerve stimulation therapy.

Dr. Nowalk, a sleep medicine research fellow at the University of Chicago, will develop expertise in advanced statistical analyses of glucose metabolism and clinical trial management through this one-year project grant. His proposed study will be the first to examine the metabolic effects of hypoglossal nerve stimulation (HNS) therapy as a surgical alternative to positive airway pressure treatment for obstructive sleep apnea, a highly prevalent sleep disorder and independent risk factor for cardiometabolic disease. Dr. Nowalk completed his internal medicine residency in 2018, served as chief resident from 2019 to 2020, and was recruited to the University of Chicago's pulmonary-critical care fellowship in 2020, where he has authored two first-author publications and delivered six national conference presentations on sleep-disordered breathing. He is currently completing a Master of Science in Public Health Sciences.

Performance occurs in Pennsylvania. The award period runs through July 30, 2026. The funding is classified as a project grant.

Abstract

Summary candidate's career goal. DR. Nathan nowalk's goal is to become an independent physician-scientist leading clinical trials to elucidate the metabolic and cardiovascular effects of obstructive sleep apnea (OSA) and how current therapies can mitigate risk and improve outcomes. Through the training outlined in this one-year F32 award, he will gain the skills necessary to perform advanced statistical analyses in metabolism and clinical trial management, which will be instrumental in him achieving this goal. Problem to be addressed. OSA is a highly prevalent sleep disorder and an independent risk factor for cardiometabolic disease. Treatment of OSA is significantly limited by intolerance to positive airway pressure (PAP). Hypoglossal nerve stimulation (HNS) therapy is a surgical alternative to PAP that is rapidly being adopted. DR. Nowalk's proposed study is the first to examine the metabolic effects of HNS therapy and will have significant impact in the care of patients with OSA. Candidate background. DR. Nowalk is a sleep medicine research fellow at the university of chicago (uchicago). He completed internal medicine residency (2018) and was selected to serve as chief resident (2019- 2020). He was recruited to uchicago for pulmonary-critical care fellowship (2020), where he has begun to develop expertise in sleep-disordered breathing with 2 first-author publications, and 6 national conference presentations. His section has a strong commitment to supporting his academic career, including selecting him for a T32 grant (2022). He is currently completing a master of science in public health sciences. Career development plan. DR. Nowalk proposes building on his early research experience and master's coursework to develop expertise in advanced statistical analyses in glucose metabolism and begin to manage and analyze clinical trials. Additionally, he will broaden his exposure to sleep research methods and the areas requiring further investigation through a portfolio of online nhlbi workshops. Mentors. DR. Nowalk has designed a complementary mentorship team at uchicago. His primary mentor is DR. Valerie press (primary sponsor) and she carries a K24 mentoring award for respiratory topics in patient oriented research. DR. Nowalk and DR. Press have met weekly since 2022. DR. Esra tasali (CO-sponsor) is a trialist studying the cardiometabolic outcomes of sleep disruption and DR. Phillip losavio (CO-sponsor) is an international expert in sleep surgery. DR. Losavio is the principal investigator for the clinical trial DR. Nowalk is working under for this proposal. Aims. Using a prospective, single-group trial of patients with OSA before and after HNS surgery, DR. Nowalk will determine the impact of HNS therapy on: glucose metabolism using continuous glucometers and fasting serum studies (aim 1) and cardiovascular health using an ambulatory blood pressure monitor, serum studies, and a wearable activity monitor (aim 2). Deliverables. During this one-year award, DR. Nowalk's aims will lead to 2-3 first-author publications and presentation at 2 international conferences. The results will serve as data for his K23 application, which will focus on a trial examining the cardiometabolic profiles of endotypes in OSA.