title: Possible role of new pressor protein in hypertensive anephric hemodialysis patients.
abstract: Unexplained hypertension was observed in three anephric children on hemodialysis. We investigated the possible involvement of a novel hypertensive extra-renal enzyme new pressor protein (NPP), related to coagulation beta-FXIIa. Currently, NPP activity can only be determined by a rat bioassay model. On study day 1, pre dialysis, patients 1, 2, and 3 were hypertensive and their plasmas raised rat systolic blood pressure (SBP) by 45, 34, and 9 mmHg, respectively. Post dialysis, patients 1 and 2 reached their estimated dry body weight and their systemic pressures dropped, while patient 3 remained hypertensive and hypervolemic. Their post-dialysis plasmas raised rat SBP by 22, 14, and 9 mmHg, respectively. On day 2, similar relationships between patient SBP, volume status, and plasma NPP-like activity in rats were observed. The characteristic rat BP responses, lack of inhibition by captopril (ruling out a renin-mediated effect), and inhibition by soybean trypsin inhibitor support co-identity with NPP. Plasma FXIIa (combined alpha-FXIIa and beta-FXIIa) was measured by immunoassay and found to be elevated in all patients. This investigation suggests that there is high endogenous NPP activity in the plasmas of these hypertensive hemodialysis patients, it changes with SBP and fluid volume, and is a possible contributor to their hypertension. Further studies are required to examine the wider applicability of these novel findings.
authors.affiliation: Division of Nephrology, The Hospital for Sick Children, 555 University Avenue, M5G 1X8, Toronto, Ontario, Canada. rachel.pearl@sickkids.ca
authors.forename: Rachel J
authors.initials: RJ
authors.lastname: Pearl
authors.forename: Peter C
authors.initials: PC
authors.lastname: Papageorgiou
authors.forename: Michael
authors.initials: M
authors.lastname: Goldman
authors.forename: Akis A
authors.initials: AA
authors.lastname: Amfilochiadis
authors.forename: Frans
authors.initials: F
authors.lastname: Boomsma
authors.forename: Rasmus
authors.initials: R
authors.lastname: Rojkjaer
authors.forename: Denis
authors.initials: D
authors.lastname: Geary
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Osmond
mesh_terms: D000293:Adolescent; D000818:Animals; D001681:Biological Assay; D001794:Blood Pressure / Q000187:drug effects; D001798:Blood Proteins / Q000494:pharmacology / Q000502:physiology*; D002648:Child; D015956:Factor XIIa / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D006977:Hypertension, Renal / Q000097:blood*; D008297:Male; D009392:Nephrectomy; D051381:Rats; D006435:Renal Dialysis; D014357:Trypsin
chemical_list: D001798:Blood Proteins; D015956:Factor XIIa; D014357:Trypsin