Amelioration of cyclosporin A effect on microvasculature by endothelin inhibitor.
BACKGROUND
We have previously shown that endothelial injury by cyclosporin A (CyA) is associated with an increased endothelin-1 (ET-1) release. We now sought to determine, in an animal model of angiogenesis, if inhibiting the effect of ET-1 on endothelial cells (ECs) would reverse the CyA-mediated endothelial injury in an animal model of angiogenesis.


METHODS
An angiogenic mixture of Matrigel (0.5 ml), fibroblast growth factor (1 ng/ml), vascular endothelial growth factor (100 ng/ml), and heparin (64 unit/ml) was injected as a subcutaneous plug in the flank of C3H mice (n = 5). In experimental groups CyA (20 mg/ml), CyA, and BQ 123 (ET-A receptor antagonist), CyA and PD 142893 (ET-A and ET-B receptor antagonist), or CyA and ET-1 antibody were added to the angiogenic mixture. Angiogenesis in the mixture was quantified by modified planimetric point counting method in skin/Matrigel cross-sections stained with factor VIII to highlight endothelial neocapillaries. Mean +/- SD of angiogenic area was analyzed with analysis of variance and Bonferroni test. The survival curves obtained by Kaplan-Meier analysis were compared between the groups, and the statistical significance of survival and mortality rates was computed by log rank's and Fisher's exact test, respectively.


RESULTS
The mean +/- SD of angiogenic area in control animals (without CyA in the angiogenic mixture) was 56.76 +/- 4.2. CyA inhibited angiogenesis in the subcutaneous angiogenic plug. Adding CyA to the angiogenic mixture significantly reduced angiogenic area (5.33 +/- 1.4, P <.001) while vehicle for CyA had no such effect (56.33 +/- 3.8, P =.10). Polyclonal ET-1 antibody or PD 142893 ameliorated the effect of CyA, whereas BQ 123 did not. The mean angiogenic areas in animals with ET-1 antibody, PD 142893, or BQ 123 in the angiogenic mixture were 57.20 +/- 7.5 (P =.06), 46.00 +/- 11.5 (P = 1.0), 8.60 +/- 2.9 (P <.001), respectively.


CONCLUSIONS
Our data show that blocking ET-B receptors specifically ameliorates the microvascular injury to the neocapillaries in angiogenesis caused by CyA. Antiendothelin-1 antibody and ETR antagonist (PD 142893) could, therefore, reduce the ill effects of CyA on microvascular endothelium.
Wilasrusmee
Chumpon
C
Department of Surgery, SUNY Upstate Medical University, Syracuse, NY 13210, USA.
Ondocin
Phil
P
Bruch
David
D
Shah
Gaurang
G
Kittur
Smita
S
Wilasrusmee
Skuntala
S
Kittur
Dilip S
DS
D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D002196:Capillaries / Q000187:drug effects; D016572:Cyclosporine / Q000008:administration & dosage / Q000037:antagonists & inhibitors* / Q000506:poisoning*; D004305:Dose-Response Relationship, Drug; D019332:Endothelin-1 / Q000037:antagonists & inhibitors / Q000276:immunology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects*; D007668:Kidney / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D051379:Mice; D008809:Mice, Inbred C3H; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects*; D018919:Neovascularization, Physiologic / Q000187:drug effects; D009842:Oligopeptides / Q000494:pharmacology; D016019:Survival Analysis
D000906:Antibodies; D019332:Endothelin-1; D009842:Oligopeptides; C076213:PD 142893; D016572:Cyclosporine