Dietary Sodium (DS) Intervention to Reduce Volume Overload and Tissue Sodium in Magnetic Resonance Imaging (MRI) for Hemodialysis (HD) Patients

Recent studies illustrate that tissue sodium is regulated by immune cells in interstitial fluids such as the skin and muscle. Localized immune responses in these tissues can promote vascular endothelial growth factor secretion to promote lymphatic release of fluid and electrolytes, which has significant implications for blood pressure control and cardiovascular health. Furthermore, sodium composition of the diet has the potential to promote beneficial gut bacteria in addition to lowering auto-immune response and blood pressure.

The purpose of this pilot study is to utilize this 21Na-MRI coil to quantify changes of sodium levels in the skin and skeletal muscle in hemodialysis treatments before and after a low-sodium diet intervention. In this study, all HD patients will undergo a 30-day observation period (CON) followed by a low-sodium diet period (INT) for 30 additional days. Testing will occur at baseline and after each time-point (three time points total). During the CON period, patients will have no changes to their normal dialysis treatment, and will be asked to follow their normal diet. During the INT period, patients will provided a low- sodium diet intervention that includes receiving 3 low sodium meals per day and snacks provided by momsmeals.com.

The study outcomes include: clinical outcomes (hospitalizations, treatment efficiency) changes in tissue sodium, cardiovascular measures (blood pressure, cardiac output, and vascular resistance) and fluid/hydration status (total body water, extracellular fluid) using bioelectrical impedance. We will also collect serum to analyze the relationship between changes in tissue sodium and serum minerals (e.g. sodium and potassium), and other factors believed to help regulate tissue sodium levels, including vascular endothelial growth factor (VEGF), and markers of inflammation (CRP, IL-6). Additionally, we plan to collect patient stool samples to analyze how changes in dietary sodium consumption impact the gut microbiome.

This study will demonstrate the feasibility of utilizing 23Na-MRI to quantify skin and muscle sodium levels, as well as provide pilot data regarding the relationship between tissue sodium accumulation, inflammation, the gut microbiome, insulin resistance, and cardiovascular health in hemodialysis patients. Results from this study will then be used to design larger trials to investigate related questions.