carboprostacyclin and Ischemia

Prostacyclin and its stable analogs play an important vascular protective role by promoting angiogenesis, but their role in arteriolar growth is unclear. Here, we examined the effect of prostacyclin stable analog carbaprostacyclin on arteriolar growth in mouse hindlimb ischemia. Using an osmotic-controlled release system to continuously deliver carbaprostacyclin or saline (control) to ischemic mouse hindlimbs for up to 14 days, we found that blood perfusion was significantly better at 7 and 14 days in carbaprostacyclin-treated mice than in saline-treated mice. Microscopic examination of the microvasculature showed more morphological signs of arteriolar formation in carbaprostacyclin- versus saline-treated legs. A double-blind, quantitative microcomputed tomography analysis indicated that carbaprostacyclin-treated legs had markedly increased vascular volume and small- to medium-sized vessel numbers that correspond to decreased vessel separation. A proteome profiler antibody array demonstrated that carbaprostacyclin-treated ischemic muscles secreted significantly higher amounts of acidic fibroblast growth factor and other chemokines. Conditioned media containing those secreted factors promoted smooth muscle cell growth and migration. Additionally, increased acidic fibroblast growth factor protein levels were detected in smooth muscle cells and skeletal myotubes at different time periods after carbaprostacyclin treatment. Furthermore, the selective peroxisome proliferation-activated receptor β/δ antagonist significantly suppressed carbaprostacyclin-induced acidic fibroblast growth factor protein production. Collectively, our data provide the first morphological and molecular evidence that local delivery of carbaprostacyclin promotes vascular growth in hindlimb ischemia, and that peroxisome proliferation-activated receptor β/δ signaling plays a critical role in inducing acidic fibroblast growth factor expression.

Topics: Animals; Cell Line; Cells, Cultured; Culture Media, Conditioned; Cytokines; Drug Delivery Systems; Epoprostenol; Fibroblast Growth Factor 1; Hindlimb; Ischemia; Mice; Mice, Inbred C57BL; Microvessels; Muscle Fibers, Skeletal; Neovascularization, Physiologic; Platelet Aggregation Inhibitors

We have previously shown that PGE(2) and PGI(2) induce recovery of transepithelial resistance (TER) in ischemia-injured porcine ileal mucosa, associated with initial increases in Cl(-) secretion. We believe that the latter generates an osmotic gradient that stimulates resealing of tight junctions. Because of evidence implicating phosphatidylinositol 3-kinase (PI3K) in regulating tight junction assembly, we postulated that this signaling pathway is involved in PG-induced mucosal recovery. Porcine ileum was subjected to 45 min of ischemia, after which TER was monitored for a 180-min recovery period. Endogenous PG production was inhibited with indomethacin (5 microM). PGE(2) (1 microM) and PGI(2) (1 microM) stimulated recovery of TER, which was inhibited by serosal application of the osmotic agent urea (300 mosmol/kgH(2)O). The PI3K inhibitor wortmannin (10 nM) blocked recovery of TER in response to PGs or mucosal urea. Immunofluorescence imaging of recovering epithelium revealed that PGs restored occludin and zonula occludens-1 distribution to interepithelial junctions, and this pattern was disrupted by pretreatment with wortmannin. These experiments suggest that PGs stimulate recovery of paracellular resistance via a mechanism involving transepithelial osmotic gradients and PI3K-dependent restoration of tight junction protein distribution.

Topics: 16,16-Dimethylprostaglandin E2; Animals; Anti-Ulcer Agents; Electric Impedance; Epoprostenol; Female; Humans; Ileum; Intestinal Mucosa; Ischemia; Male; Membrane Proteins; Microscopy, Electron; Occludin; Osmotic Pressure; Phosphatidylinositol 3-Kinases; Phosphoproteins; Platelet Aggregation Inhibitors; Recovery of Function; Signal Transduction; Swine; Tight Junctions; Urea; Zonula Occludens-1 Protein

Prostacyclin, the stable prostacyclin analogue carbacyclin, the thromboxane synthetase inhibitor UK-38,485, and the phosphodiesterase inhibitor dipyridamole were tested on rabbit epigastric free flaps for their ability to improve flap survival after a period of ischemia. Control flaps infused with a balanced salt solution had a 39.9% survival, whereas prostacyclin, carbacyclin, and dipyridamole significantly increased flap survival to 68.4% (P less than 0.05), 66.4% (P less than 0.05), and 66.9% (P less than 0.05), respectively. UK-38,485 improved survival slightly to 47.6% although not significantly. The improved flap survival correlated with the vasodilatory properties of the three successful agents whereas the antithrombotic properties of UK-38,485 were not sufficient, on their own, to increase flap survival.

Topics: Animals; Dipyridamole; Epoprostenol; Graft Survival; Imidazoles; Ischemia; Prostaglandins, Synthetic; Rabbits; Skin; Skin Transplantation; Surgical Flaps; Thromboxane-A Synthase