Mechanistic Study of Nicotinamide Riboside on NAD+ Biology in Individuals With Combined Pulmonary Hypertension

Pulmonary hypertension (PH) is a serious condition that puts strain on the heart and lungs and often leads to frequent hospital stays and shortened life expectancy. The most common cause is heart disease affecting the left side of the heart. A particularly high-risk form, called combined pre- and post-capillary pulmonary hypertension (CPH), occurs in about one in four people with heart failure. There are currently no approved treatments for CPH, and many patients develop right-sided heart failure and die earlier than expected. This study is based on a new approach that uses advanced computer methods to analyze a patient's unique biology and identify potential drug targets. Using this method, we identified nicotinamide riboside (NR) as a promising option for people with CPH. NR is a form of vitamin B3 that helps the body make NAD⁺, a substance essential for how cells produce energy and stay healthy. NAD⁺ plays an important role in how heart and blood vessel cells function. Previous research in animals suggests NR may help improve blood vessel changes in the lungs and support heart function. NR has also shown potential benefits in human studies related to cell energy, mitochondrial health, and reducing oxidative stress. In this study, NR is used only as a dietary supplement that supports normal body processes, not as a proven treatment. The investigators will conduct a small, carefully controlled study in which participants receive NR and a placebo at different times. The goal is to understand how NR affects biological and biochemical markers in the body, not to test whether it improves symptoms or outcomes. Any clinical measurements are included only to help interpret the biological effects.