Salt and TH-17 in Healthy Human Subjects

In recent years, dietary sodium intake has dramatically increased and has been shown to play an active role in a number of detrimental diseases including hypertension and cardiovascular complications. Additionally, in the developed world, there has been a steady increase in autoimmune diseases. Type 17 helper T cells (Th17) have been shown to play an active role in the development of autoimmune diseases. Serum glucocorticoid kinase (SGK1) has been shown to influence sodium transport and salt homeostasis in many cell types (Wulf, J. Clin. Invest. 2002; Salker, Nature Med 2011). Prior in vitro and in vivo studies have shown that an increase in salt concentration in the media or dietary salt intake in mice induces SGK1 expression and enhances TH17 cell differentiation and worsens experimental autoimmune encephalomyelitis (EAE), animal model for multiple sclerosis (Kleinewietfeld, Nature 2013; Wu, Nature 2013). The findings in this study can substantially increase the investigators understanding of environmental factors that modulate the development of autoimmunity in humans. In animal models the worsening effects of a high salt diet on EAE are dramatic. To the investigators knowledge, the proposed study will be the first to determine if salt intake has the same adverse impact in humans. If documented, one could envision the development of a novel treatment approach for human autoimmunity via the regulation of salt intake. Thus, the overall goal of this study is to evaluate the association between sodium and TH17 cells in human subjects. In addition to measuring TH17 cells by flow cytometry the investigators will also measure interleukins such as IL-17a, IL-17f, IL-23 that are important in TH17 differentiation and production.