title: A new antihypertensive agent that antagonizes the prohypertensive effect of endogenous ouabain and adducin.
abstract: Endogenous Ouabain (EO) and Adducin enhance the Na-K pump function and play an important role in sodium homeostasis and blood pressure (BP) regulation. In the general population, plasma EO modulates BP either by inhibiting the prohypertensive effect of an excessive salt intake or counteracting the depressor action of normal-moderate salt intake. Almost 50% of hypertensive patients have increased circulating plasma levels of EO. EO has been associated both to left ventricular dysfunction and hypertrophy. A new antihypertensive agent, PST2238, (17beta-(3-furyl)-5beta-androstan-3beta, 14beta, 17alpha-triol a digitoxigenin derivative) able to selectively antagonize both the EO and adducin prohypertensive and molecular effects, has been developed. In hypertensive rats (MHS strain) carrying both adducin mutations and increased plasma EO and in ouabain-infused rats (OS), PST2238 lowers BP by normalizing the renal Na-K pump function. In OS rats, PST antagonized the cardiac and renal pro-hypertrophic ouabain effect associated to the activation of the Src-EGFr-ERK(1/2) signaling cascade. Phase 1 clinical studies demonstrated a high tolerability of PST2238. In a preliminary phase 2 study on 42 mild never-treated hypertensive patients, PST2238 given for 3 months at 0.5 mg/day, significantly reduced BP in subjects with moderate salt intake, implying that it may be selectively effective in conditions where EO plays a prohypertensive role. In conclusion, PST2238, because of its peculiar action mechanism, represents a new tool to disentangle the complex relationship between salt intake, genetic control of renal sodium handling and EO effect.
authors.affiliation: Division of Nephrology, Dialysis and Hypertension, University "Vita-Salute" San Raffaele Hospital, Via Olgettina 60, 20132 Milan, Italy. manunta.paolo@hsr.it
authors.forename: Paolo
authors.initials: P
authors.lastname: Manunta
authors.forename: Mara
authors.initials: M
authors.lastname: Ferrandi
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Messaggio
authors.forename: Patrizia
authors.initials: P
authors.lastname: Ferrari
mesh_terms: D000732:Androstanols / Q000494:pharmacology* / Q000627:therapeutic use*; D000959:Antihypertensive Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002148:Calmodulin-Binding Proteins / Q000037:antagonists & inhibitors* / Q000097:blood; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D010042:Ouabain / Q000037:antagonists & inhibitors* / Q000097:blood / Q000494:pharmacology; D012307:Risk Factors; D012965:Sodium Chloride / Q000008:administration & dosage / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000187:drug effects / Q000502:physiology; D000099291:Adducins
chemical_list: D000732:Androstanols; D000959:Antihypertensive Agents; D002148:Calmodulin-Binding Proteins; D010042:Ouabain; D012965:Sodium Chloride; D000254:Sodium-Potassium-Exchanging ATPase; D000099291:Adducins; C106263:rostafuroxin