14 Clinical Trials for Various Conditions
This study aims to assess the salt sensitive blood pressure response to dietary salt load compared with radiological markers of salt handling.
Salt sensitive hypertension is a significant health problem worldwide and a primary modifiable risk factor for renal, cardiovascular, and cerebrovascular diseases. Yet, the underlying mechanisms remain poorly understood. The proposed study determines how renal oxygenation and substrate metabolism differs between individuals with and without salt sensitivity, with the ultimate goal of identifying mechanisms, diagnostic criteria, and treatment strategies for salt sensitive hypertension.
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.
The purpose of this study is to determine if the drug Celebrex changes the way the kidney gets rid of salt and maintains blood pressure.
Some patients with high blood pressure can experience an increase of blood pressure by 10 percent or more by taking in salt. These patients are referred to as having "salt-sensitive" (SS) hypertension. Previous studies conducted on patients with salt sensitive hypertension suggest that their portion of the nervous system responsible for maintaining normal blood pressure (autonomic nervous system) may respond differently to salt than patients with non-salt sensitive (NSS) hypertension. This study is designed to examine the response of the nervous system to high doses of salt in patients with salt-sensitive hypertension and patients with non-salt sensitive hypertension.
The overall objective of this project is to identify the key salt-sensing regions of the brain and determine the underlying mechanism of sodium sensing. The investigators will assess how the brain responds to an acute increase of salt in the blood using MRI. This will be done during a 30-minute infusion of a saline solution containing 3% salt. One trial will be conducted with a salt sensing channel blocker and one trial without the salt sensing channel blocker. This will help to assess the role of a specific salt sensing channel in the brain. Salt sensitivity of BP will be assessed using 7-day dietary feeding where participants will be given food to consume for 7-days. Comparisons will be made between salt resistant (no change in blood pressure going from low to high salt diets) and salt sensitive adults (a change in blood pressure going from low to high salt diets). The investigators think the changes in MRI will be greater in salt sensitive compared to salt resistant subjects.
The ability of the brain to sense changing sodium levels in the blood is critical in mediating the neurohumoral responses to hypernatremia, however, the mechanisms underlying sodium sensing in humans is poorly understood. The purpose of this study is to identify key sodium-sensing regions of the human brain in older adults and determine if the Na-K-2Cl co-transporter mediates the neurohumoral response to acute hypernatremia. Completion of this project will increase our understanding of blood pressure regulation, which has major public health implications.
The purpose of this research is to learn about how salt in the diet influences blood pressure in young adults who were born prematurely.
Salt-sensitive hypertension affects nearly 50% of the hypertensive and 25% of the normotensive population, and strong evidence indicates that reducing salt intake decreases blood pressure and cardiovascular events. The precise mechanisms of how dietary salt contributes to blood pressure elevation, renal injury, and cardiovascular disease remains unclear. Our data indicated that monocytes exhibit salt sensitivity, and the investigators hypothesize that of salt sensitivity of these and similar immune cells correlate with the hypertensive response to salt intake. Currently, the research tools for diagnosing salt-sensitivity are costly, time consuming and laborious. In this study the investigators will identify monocyte salt-sensitivity as a marker of salt-sensitive hypertension.
Previous studies have demonstrated that single nucleotide polymorphisms (SNPs) of the sodium-bicarbonate co-transporter gene (SLC4A5) are associated with hypertension. We tested the hypothesis that SNPs in SLC4A5 are associated with salt sensitivity of blood pressure in 185 whites consuming an isocaloric constant diet with a randomized order of 7 days of low sodium (Na+) and 7 days of high Na+ intake. Salt sensitivity was defined as a ≥7-mm Hg increase in mean arterial pressure during a randomized transition between low and high Na+ diet. A total of 35 polymorphisms in 17 candidate genes were assayed, 25 of which were tested for association. Association analyses with salt sensitivity revealed 3 variants that associated with salt sensitivity. Of these, 2 SNPs in SLC4A5 (rs7571842 and rs10177833) demonstrated highly significant results and large effects sizes, using logistic regression. These 2 SNPs had P values of 1.0×10-4 and 3.1×10-4 with odds ratios of 0.221 and 0.221 in unadjusted regression models, respectively, with the G allele at both sites conferring protection. These SNPs remained significant after adjusting for body mass index and age (P=8.9×10-5 and 2.6×10-4 and odds ratios 0.210 and 0.286, respectively). Furthermore, the association of these SNPs with salt sensitivity was replicated in a second hypertensive population. Meta-analysis demonstrated significant associations of both SNPs with salt sensitivity (rs7571842 \[P=1.2×10-5\]; rs1017783 \[P=1.1×10-4\]). In conclusion, SLC4A5 variants are strongly associated with salt sensitivity of blood pressure in 2 separate white populations.
This investigation aims to determine the effects of a 4-week yoga intervention on sodium-induced pressor and endothelial function responses as well as markers of renal sodium handling in African American adults.
The kidney plays a crucial role in maintaining salt balance by two opposing physiological mechanisms: the renal dopaminergic system which enhances salt excretion and the renin-angiotensin system (RAS) which causes salt retention. Salt-sensitive hypertension occurs when this balance is altered or abnormal. We hypothesized that this balance is influenced by salt intake: therefore dietary salt affects the natriuretic response to the renal dopaminergic agonist Fenoldopam, and the Angiotensin Converting Enzyme inhibitor, Enalapril. In this trial we study normal salt balance mechanisms in salt resistant adults with normal blood pressure.
High blood pressure, or hypertension, is a serious problem in the African-American (AA) population which affects nearly 7 of every 10 AAs in our area. Previously the investigators showed that a significant number of AAs held onto or retained salt during mental stress (sodium retainers). The investigators believe that the increased salt load and resulting blood pressure load contributes to the eventual development of hypertension in these individuals. The purpose of this study is to find out if this response is due to the direct stimulation of the kidney (the organ that controls salt levels in the body, by the brain). To do this, the investigators will determine if a drug that stops the connection between the brain and the kidney during mental stress will prevent sodium retention in sodium retainers. Prazosin is an alpha adrenergic receptor blocker that has been approved by the Food and Drug Administration (FDA). None of the subjects who participate in this study have high blood pressure. The subjects will not know which testing week is the drug week and which is the placebo week.
The purpose of this study is to test the hypothesis that blood pressure sensitivity to high sodium intake in healthy humans is characterized by increased urinary excretion of two endogenous sodium pump inhibitors, marinobufagenin (MBG), and ouabain-like compound (OLC). The study also tests the hypothesis that women who breathe slowly and have high resting end tidal CO2 at rest are more likely to have low plasma renin activity and sodium sensitivity of blood pressure than those who breathe more rapidly and maintain lower end tidal CO2.