Clinical Research Directory

Effect of a Daily Supplement on Plasma PAI-1 Levels

In a healthy person, the production of nitric oxide (NO) by the endothelium, the inner lining of the blood vessel, is responsible for a) the ability of the blood vessel to dilate so it can increase its blood flow and b) act as an anti-clotting product to prevent blood clotting in those vessels. Under physiological stress either due to the development of a disease such as diabetes or simply from aging, the endothelial cells can be impacted and become dysfunctional, thereby impairing their ability to make NO and even promoting the development of blood clots. When such endothelial dysfunction occurs, it may be a precursor for the future development of cardiovascular (CV) disease like hypertension or coronary artery disease later on in life in these patients. Therefore, the ability to enhance the local production or availability of NO within such affected blood vessels in patients identified as prone to endothelial dysfunction could play a positive role in either preventing or delaying the onset of endothelial dysfunction and subsequent CV disease in such patients. RM is an oral supplement consisting of natural ingredients and the amino acid, L-citrulline. In laboratory experiments with cells from the inner lining of blood vessels, the four components of RM have been shown to increase the concentration of NO and decrease the levels of some aging markers. In our recently completed study (manuscript currently in review), 31 young men and women took the supplement for 14 days and had no serious side effects. The supplement caused the expected potentially beneficial dilation of the blood vessels and decrease in the levels of Plasminogen Activator Inhibitor-1 (PAI-1), whose levels correlate with aging and risk of cardiovascular disease. In this study, healthy participants will consume the supplement for a 6-week period to determine if PAI-1 levels continue to be suppressed and also examine whether the supplement has an effect on other blood markers whose levels can change with aging or cardiovascular disease and may also be indicative or predictive of an illness.

Multiparametric MRI in a Prospective Cohort of Living Kidney Donors, Recipients, and Healthy Controls: Correlations With Markers of Renal Function, Fibrosis and Ageing

Development of renal fibrosis is the irreversible culmination of various renal diseases and independently predicts adverse outcomes. Currently renal fibrosis can only be diagnosed by performing a renal biopsy. The procedure is invasive and is limited by sampling bias. In recent years there has been a significant development in magnetic resonance imaging (MRI) based techniques. MRI can provide highly detailed anatomical images. Other MRI measures allow quantitative measurements of perfusion, oxygenation, tissue stiffness and diffusion of water molecules within tissue. The combination of several MRI techniques sensitive to different biophysical tissue properties in a single scan session is referred to as multiparametric MRI (mpMRI). Emerging evidence suggests that mpMRI could represent a method for indirect characterization of renal microstructure and extent of fibrosis. So far, studies performed in living kidney donors and recipients have been mostly cross-sectional. For mpMRI to transition to the clinical setting there is a need for validation of MRI-based measures with currently used reference methods for quantifying renal function and fibrosis. The aim of this longitudinal observational study in a cohort of living kidney donors, recipients and healthy controls is to investigate the utility of repeated mpMRI over a period of 2 years. MRI-based measures will be compared to current reference methods for quantifying renal function and fibrosis. The investigators hypothesize that there will be significant correlations between MRI-based measures, renal function determined by precise measurement of glomerular filtration rate and extent of fibrosis determined by renal biopsy. MRI-based measures are expected to be predictive of renal function decline and development of renal fibrosis. This study could provide valuable data that will be helpful in moving the field of renal mpMRI forward, with the goal of providing a novel and non-invasive method for the diagnosis of renal pathology.