title: Renal hemodynamics and renoprotection.
abstract: BACKGROUND
  Angiotensin II (AII) is the well-known determinant of kidney damage increasing intraglomerular pressure, matrix expansion and fibroblast proliferation. Renin-angiotensin system (RAS) inhibition, limiting the hemodynamic effects of AII, reduces proteinuria and is renoprotective in the long term.
  
  
  METHODS
  We studied 15 chronic proteinuric patients by Doppler ultrasonography to clarify the intrarenal hemodynamic changes during RAS blockade by Benazepril (10-20 mg/day) alone and combined with Valsartan (80-160 mg/day). We also investigated the correlation between hemodynamic indices, RAS components and antiproteinuric effect.
  
  
  RESULTS
  After 1 month of Benazepril proteinuria, resistive index (RI) and pulsatility index (PI) significantly decreased and proteinuria reduction was directly correlated to decrease in RI (r = 0.55, p = 0.03). Contrarily, after 1 month of combined therapy, RI and PI restored to baseline and progressively increased in the following 3 months, while proteinuria decreased. Increase in RI was directly correlated to concomitant increase in plasma renin activity (r = 0.65, p = 0.01) suggesting a direct role of renin in restoring intrarenal resistances.
  
  
  CONCLUSIONS
  The hemodynamic changes caused by RAS inhibitors partially contribute to the antiproteinuric effect. Other RAS components, such as renin, may contribute to renal vasoconstriction and could be a further determinant of kidney damage besides a promising target for renoprotection.
authors.affiliation: Internal Medicine Department, University of Sassari, Sassari, Italy. giacominal@tiscali.it
authors.forename: Giacomina
authors.initials: G
authors.lastname: Loriga
authors.forename: Gianpaolo
authors.initials: G
authors.lastname: Vidili
authors.forename: Piero
authors.initials: P
authors.lastname: Ruggenenti
authors.forename: Rossana
authors.initials: R
authors.lastname: Faedda
authors.forename: Marcella
authors.initials: M
authors.lastname: Sanna
authors.forename: Andrea E
authors.initials: AE
authors.lastname: Satta
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage*; D001552:Benzazepines / Q000008:administration & dosage; D005260:Female; D006801:Humans; D006977:Hypertension, Renal / Q000503:physiopathology* / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D011507:Proteinuria / Q000503:physiopathology* / Q000517:prevention & control*; D012079:Renal Circulation / Q000187:drug effects*; D012083:Renin / Q000378:metabolism; D012084:Renin-Angiotensin System / Q000187:drug effects*; D013777:Tetrazoles / Q000008:administration & dosage; D016896:Treatment Outcome; D014633:Valine / Q000008:administration & dosage / Q000031:analogs & derivatives; D000068756:Valsartan
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D001552:Benzazepines; D013777:Tetrazoles; D000068756:Valsartan; D012083:Renin; D014633:Valine; C044946:benazepril