Susan M. Wall, MD
Department of Medicine
Emory University School of Medicine
Dr. Susan Wall received an Honors B.S. in Chemistry from the University of Washington and then her M.D. from St. Louis University School of Medicine. She did her Internship and Residency at the U.C.L.A. San Fernando Valley Program and then did a Clinical and Research Fellowship in Nephrology at U.C.L.A. During her fellowship at U.C.L.A. she became interested in the physiology of the renal regulation of acid-base balance. She extended her laboratory training by doing a second research fellowship at the Kidney and Electrolyte Laboratory of the National Heart, Lung and Blood Institute at the National Institutes of Health. She then joined the Nephrology Division at the University of Texas, Health Science Center at Houston, where she rose from Assistant to Associate Professor. She came to Emory in 2002 and is now Professor of Medicine and Physiology. Her laboratory initially studied the role of ammonium transport along the collecting duct and its role in the renal regulation of acid-base balance. More recently, her research involves the study renal Cl- transporters and their role in the regulation of blood pressure.
Dr. Wall’s laboratory has made major contributions to our understanding of the renal regulation of net acid secretion and blood pressure. They were the first to characterize direct, transepithelial transport of ammonium (NH4+) along the collecting duct. Previously it was believed that NH4+ secretion along the collecting duct occurs exclusively through active H+ secretion in parallel with the nonionic diffusion of NH3. Wall and colleagues observed direct NH4+ transport along the collecting duct, mediated by the Na,K-ATPase. She observed that Na,K-ATPase-mediated NH4+ uptake represents 50% of net acid secreted along the terminal inner medullary collecting duct during hypokalemia, which contributes to the metabolic alkalosis observed in this treatment model. Because NH4+ is the major regulatable component of net acid secretion, these observations provide an important and novel mechanism for the renal regulation of net acid secretion.
More recently, Dr. Wall has studied the contribution of renal Cl- transporters to the maintenance of vascular volume, blood pressure and acid-base balance. She and her colleagues have localized the Cl-/HCO3- exchanger pendrin (Slc26a4) to the apical region of subpopulations of intercalated cells within the distal nephron. Pendrin, she observed, is upregulated following aldosterone, primarily by changing the subcellular distribution of pendrin from the subapical space to the apical plasma membrane. Pendrin mediates HCO3- secretion and Cl- absorption, which reduces arterial pH and expands vascular volume, thereby increasing blood pressure. The Wall Laboratory first described the novel role of pendrin in blood pressure regulation. Pendrin plays an important role in the hypertensive response to aldosterone by increasing the renal absorption of Cl-.
Dr. Wall attends on the Renal Consult service at Emory University Hospital. Her main clinical interests are in the pathophysiology of acid-base and blood pressure regulation. She is also interested in the removal of drugs through dialysis.
Dr. Wall teaches acid-base physiology in the Medicine Course for the second year medical students. She also participates in the Renal Physiology course for the medical students and has been on graduate student thesis committees.
Dr. Wall now serves as a regular member of the National Institutes of Health Cellular and Molecular Biology of the Kidney Study Section (CMBK). She is also a member of numerous national medical societies such as the American Society for Clinical Investigation (ASCI), the American Society of Nephrology and the American Physiological Society. She was Chair of the Renal Section of the American Physiological Society from 2002-2005
Dr. Wall’s research interest is Pendrin, a protein that is found in the interchelated cells in the kidney cortex. The clinical pathology related to lack of pendrin is Pendred Syndrome.
Pendrin is involved in the acid base balance of the kidney cortex and has recently been related by Dr. Wall to effects on blood pressure.
Dr. Wall’s lab includes a postdoctoral fellow (Dr. Vladimir Pech, tubule perfusionist), Dr. Young Hee Kim (immunohistology expert), a couple research specialists.