Clinical Research Directory

Effect of an Isolevuglandin Scavenger on Salt Sensitivity of Blood Pressure and Immune Cell Activation in Humans

Hypertension is the leading cause of preventable deaths globally, driven by complications such as myocardial infarction, stroke, heart failure, and kidney disease. Recent updates in hypertension classification by the American Heart Association (AHA) place nearly half of the U.S. population in the hypertensive category. Excess dietary salt is a major risk factor for hypertension, with 50% of hypertensive individuals exhibiting salt-sensitivity of blood pressure (SSBP). SSBP is an independent predictor of cardiovascular events and death. While kidney mechanisms in salt-sensing have been extensively studied, emerging evidence suggests that immune cells can also sense sodium (Na+). This trial hypothesizes that myeloid cell-derived isolevuglandins (IsoLGs) drive endothelial dysfunction, perpetuating the salt-sensitive phenotype. Preliminary data indicate that targeting IsoLGs with the IsoLG scavenger 2-hydroxybenzylamine (2-HOBA) may interrupt this immune-vascular axis, reducing salt sensitivity and associated cardiovascular risks. This phase 2 clinical trial aims to investigate the role of 2-HOBA in modulating immune cell function within blood vessels in hypertensive patients. The study will explore the impact of immunity on salt sensitivity and assess 2-HOBA's potential to reduce endothelial dysfunction, improve immune cell activation, and alleviate SSBP.

CARDIA-Salt Sensitivity of Blood Pressure (SSBP)

Salt sensitivity of blood pressure (SSBP) is defined as the change in blood pressure (BP) in relation to change in salt intake. An increase in BP from low- to high-salt diet is common and associated with an increased risk of cardiovascular morbidity and mortality, even among normotensive individuals. Yet, the pathophysiology of SSBP is not well understood. The prevailing paradigm is that abnormalities of neurohormones that regulate sodium (Na+) retention and excretion and/or Na+ transporting pathways create Na+ imbalances that underlie susceptibility to SSBP. As a homeostatic mechanism, BP fluctuates to maintain Na+ balance, i.e. higher BP is needed for pressure natriuresis to excrete excess Na+. An alternate framework emphasizes vascular dysregulation as the inciting mechanism. In both constructs, how Na+ itself influences BP remains incompletely understood. Our preliminary work suggests that excess Na+ induces a pro-inflammatory state that sustains higher BP. Interleukin-6 (IL-6) drives the induction of interleukin-17 (IL-17) secreting T helper 17 cells that were recently demonstrated to be pathogenic in response to Na+ exposure. IL-6, IL-17 and related cytokines regulate renal Na+ transporters and raise BP through vascular inflammation, fibrosis, and impaired vasodilation. The immune response to high- and low-salt diet in humans, however, is not completely understood, emphasizing the need for more detailed human studies, with deeper immune profiling under controlled salt conditions and with neurohormonal assessment. Our overarching postulate is that the inflammatory response to excess dietary salt intake is associated with SSBP. The Coronary Artery Risk Development in Young Adults (CARDIA) study is the ideal cohort in which to translate our preliminary findings. Investigators propose to investigate SSBP in CARDIA using standardized low- and high-salt diets and 24-hour ambulatory BP monitoring. Investigators will quantify SSBP in a total of 500 participants from the Chicago and Birmingham field centers during the upcoming year 35 exam (beginning in 2020). Our specific aims are: 1) to define the distribution of SSBP and its clinical correlates in a contemporary community-based US cohort of middle-aged individuals; 2) to investigate the immune response to dietary salt loading, and 3) to investigate the association between the immune and BP responses to dietary salt loading. The proposed study represents a unique opportunity to leverage a large, well-phenotyped cohort to test novel hypotheses regarding SSBP. Phenotyping SSBP using standardized high- and low-salt diets in CARDIA will be novel as this has never been performed in any of the existing US based NHLBI sponsored cardiovascular epidemiologic cohorts. The proposed work has the potential to yield a more readily available approach for differentiating an individual as salt-sensitive or resistant. New insights into the pathophysiology of SSBP should also provide a foundation for investigating high-impact clinical applications, by informing future studies of therapies directed at SSBP. The scientific rigor is further enhanced by the rich clinical, genetic, and biochemical data available in CARDIA.