Cardio-renal integration in physiological and pathophysiological conditions; Neuro-humoral and hemodynamic mechanisms in homeostasis, heart failure and hypertension.
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In the past 20 years, our laboratory has been concerned with physiological and pathophysiological aspects of cardio-renal integration, primarily related to neurohormonal control of body fluid-volume and pressures. Current areas of research include circulatory and tissue renin-angiotensin-aldosterone axis, natriuretic peptides, nitric oxide, prostaglandins, and more recently, the newly discovered hormone leptin. This hormone is primarily synthesized and secreted by adipocytes, and one of its major well described functions is the control of appetite. However, in addition to its role as an "antiobesity hormone," increasing evidence suggests that leptin may have potent effects and wider actions influencing autonomic, cardiovascular, endocrine and renal functions. Indeed, novel observations from this and other laboratories have suggested important natriuretic and vascular actions of this peptide-hormone during pharmacological infusions. However, the cardio-renal role of endogenous leptin is not well characterized, either during homeostasis or in pathological conditions. Basic and clinical research from our laboratory is directed at examining mechanisms of action, hemodynamic factors and neurohormonal interactions involved in the biological expression of leptin in healthy and disease states, such as obesity, hypertension and heart failure.
Villarreal D, Reams G, Freeman RH. Effects of renal denervation on the sodium excretory actions of leptin in hypertensive rats. Kidney Intl. 58:989-994, 2000.
Villarreal D, Freeman R, Reams GP. Natriuretic peptides and salt sensitivity: endocrine cardio-renal integration in heart failure. Congest Heart Fail Jan - Feb 2002;8(1):29-36.
Villarreal D, Reams GP, Samar H, Spear R, Freeman RH. Effects of chronic nitric oxide inhibition on the renal excretory response to leptin. Obes Res June 12, 2004;(6):1006-10.
Villarreal D, Reams GP, Freeman RH, Spear R, Tchoukina I, Samar H. Leptin blockade attenuates sodium excretion in saline-loaded normotensive rats. Mol Cell Biochem, Feb 2006;283(1-2):153-57.
Patel SB, Reams GP, Spear RM, Freeman RH, Villarreal D. (2008) Leptin: Linking Obesity, The Metabolic Syndrome and Cardiovascular Disease. Current Hypertension Reports 2008;10(2):131-137.
Kshatriya S, Spear R, Villarreal D, Reams G, Freeman R, Dietz J (2009) Obesity-Hypertension: The Emerging Role of Leptin in Renal and Cardiovascular Dyshomeostasis. Current Opinion in Nephrology and Hypertension (in press).