title: Modulation of pre-capillary arteriolar pressure with drag-reducing polymers: a novel method for enhancing microvascular perfusion.
abstract: OBJECTIVE
  We have shown that drag-reducing polymers (DRP) enhance capillary perfusion during severe coronary stenosis and increase red blood cell velocity in capillaries, through uncertain mechanisms. We hypothesize that DRP decreases pressure loss from the aorta to the arteriolar compartment.
  
  
  METHODS
  Intravital microscopy of the rat cremaster muscle and measurement of pressure in arterioles (diameters 20-132 μm) was performed in 24 rats. DRP (polyethylene oxide, 1 ppm) was infused i.v. and measurements were made at baseline and 20 minutes after completion of DRP infusion. In a 10-rat subset, additional measurements were made three minutes after the start, and one to five and 10 minutes after completion of DRP.
  
  
  RESULTS
  Twenty minutes after the completion of DRP, mean arteriolar pressure was 22% higher than baseline (from 42 ± 3 to 49 ± 3 mmHg, p < 0.005, n = 24). DRP decreased the pressure loss from the aorta to the arterioles by 24% (from 35 ± 6 to 27 ± 5 mmHg, p = 0.001, n = 10). In addition, there was a strong trend toward an increase in pressure at 10 minutes after the completion of DRP (n = 10).
  
  
  CONCLUSIONS
  Drag-reducing polymers diminish pressure loss between the aorta and the arterioles. This results in a higher pre-capillary pressure and probably explains the observed DRP enhancement in capillary perfusion.
authors.affiliation: Department of Medicine, Cardiovascular Institute, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA. pacellajj@upmc.edu
authors.forename: John J
authors.initials: JJ
authors.lastname: Pacella
authors.forename: Marina V
authors.initials: MV
authors.lastname: Kameneva
authors.forename: Judith
authors.initials: J
authors.lastname: Brands
authors.forename: Herbert H
authors.initials: HH
authors.lastname: Lipowsky
authors.forename: Hans
authors.initials: H
authors.lastname: Vink
authors.forename: Linda L
authors.initials: LL
authors.lastname: Lavery
authors.forename: Flordeliza S
authors.initials: FS
authors.lastname: Villanueva
mesh_terms: D000818:Animals; D001160:Arterioles / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects*; D004337:Drug Carriers / Q000494:pharmacology*; D008297:Male; D051379:Mice; D018482:Muscle, Skeletal / Q000098:blood supply*; D011092:Polyethylene Glycols / Q000494:pharmacology*; D017208:Rats, Wistar
chemical_list: D004337:Drug Carriers; D011092:Polyethylene Glycols