Prostacyclin Synthase Gene Transfer Research Articles

Attenuation of Monocrotaline-Induced Pulmonary Hypertension by Luminal Adeno-Associated Virus Serotype 9 Gene Transfer of Prostacyclin Synthase

Idiopathic pulmonary arterial hypertension (iPAH) is associated with high morbidity and mortality. We evaluated whether luminal delivery of the human prostacyclin synthase (hPGIS) cDNA with adeno-associated virus (AAV) vectors could attenuate PAH. AAV serotype 5 (AAV5) and AAV9 vectors containing the hPGIS cDNA under the control of a cytomegalovirus-enhanced chicken β-actin (CB) promoter or vehicle (saline) were instilled into lungs of rats. Two days later, rats were injected with monocrotaline (MCT, 60 mg/kg) or saline. Biochemical, hemodynamic, and morphologic assessments were performed when the rats developed symptoms (3-4 weeks) or at 6 weeks. Luminal (airway) administration of AAV5 and AAV9CBhPGIS vectors (MCT-AAV5 and MCT-AAV9 rats) significantly increased plasma levels of 6-keto-PGF1(α) as compared with MCT-controls, and closely resembled levels measured in rats not treated with MCT (saline-saline). Right ventricular (RV)/left ventricular (LV)+septum (S) ratios and RV systolic pressure (RVSP) were greater in MCT-control rats than in saline-saline rats, whereas the ratios and RVSP in MCT-AAV5CBhPGIS and MCT-AAV9CBhPGIS rats were similar to saline-saline rats. Thickening of the muscular media of small pulmonary arteries of MCT-control rats was detected in histological sections, whereas the thickness of the muscular media in MCT-AAV5CBhPGIS and MCT-AAV9CBhPGIS rats was similar to saline-saline controls. In experiments with different promoters, a trend toward increased levels of PGF1(α) expression was detected in lung homogenates, but not plasma, of MCT-treated rats transduced with an AAV9-hPGIS vector containing a CB promoter. This correlated with significant reductions in the RV/LV+S ratio and RVSP in MCT-AAV9CBhPGIS rats that resembled levels in saline-saline rats. No changes in levels of PGF1(α), RV/LV+S, or RVSP were detected in rats transduced with AAV9-hPGIS vectors containing a modified CB promoter (CB7) or a distal epithelial cell-specific promoter (CC10). Thus, AAV9CBhPGIS vectors prevented development of MCT-induced PAH and associated pulmonary vascular remodeling.

310. Attenuation of Monocrotaline-Induced Pulmonary Hypertension in Rats by Luminal Delivery of AAV Prostacyclin Synthase Gene Transfer Vectors

310. Attenuation of Monocrotaline-Induced Pulmonary Hypertension in Rats by Luminal Delivery of AAV Prostacyclin Synthase Gene Transfer Vectors

Prostacyclin synthase gene transfer inhibits neointimal formation by suppressing PPARδ expression

Objective Prostacyclin (PGI 2) is a potent ligand of peroxisome proliferator-activated receptor δ (PPARδ) that regulates cell growth and differentiation. The aim of this study was to elucidate how endogenous PGI 2 overexpression affects the expressions of PPARδ and mitogen-activated protein kinases (MAPKs) in the development of neointimal formation in experimental angioplasty with adenovirus-mediated PGI 2 synthase (Ad-PGIS) gene transfer. Methods and results In human aortic smooth muscle cells, protein blotting analysis showed that PGI 2 overproduction decreased the levels of phosphorylated p38 MAPK (P-p38 MAPK) (2.0-fold versus 0.83-fold relative to control). Immunohistochemical analysis in balloon-injured arteries revealed diffuse expression of PPARδ in the neointima of control vessels, with no expression in uninjured vessels. The level of PPARδ expression was lower in Ad-PGIS-treated arteries than in control vessels, with the PPARδ localized in the neointima adjacent to endothelium. Staining of P-p38 MAPK showed a similar pattern to PPARδ among the three groups. Morphometric analysis at day 14 revealed that Ad-PGIS reduced the intima-to-media ratio by up to 59%. Conclusions Ad-PGIS gene transfer reduced PPARδ expression and inhibited neointimal formation after balloon injury in accordance with the reduction in the phosphorylation of p38 MAPK.

865. In Vivo Gene Transfer of Prostacyclin Synthase by Using AAV Vector Prevents Monocrotaline-Induced Pulmonary Hypertension and Pulmonary Vasoconstriction in Rats

Background: Prostacyclin synthase (PGIS) is the final committed enzyme for biosynthesis of prostacyclin (PGI2), which ameliorates survival and symptoms in pulmonary arterial hypertension (PAH). However, the therapeutic option of PGI2 is limited by its short half-life, requirement of continuous infusion, and catheter-related complications. Although PGIS gene transfer would effectively and stably express PGI2, previous strategies have several limitations; intratracheal approach may deteriorate respiratory function in critical PAH patients, and intrahepatic approach may cause liver hemorrhage and peritonitis. Thus, intramuscular PGIS gene transfer is considered promising than the others. Nonetheless, a plasmid-based approach has encountered problems arising from transient and insufficient gene expression. Here we employed an adeno-associated virus (AAV) vector for an improved intramuscular gene transfer to prevent monocrotaline (MCT)-induced PAH.

Catheter-based prostacyclin synthase gene transfer prevents in-stent restenosis in rabbit atheromatous arteries.

Prostacyclin synthase (PGIS) gene transfer have been shown to accelerate re-endothelialization and prevent neointimal formation in balloon-injured arteries. The aim of this study is to evaluate how overexpression of endogenous prostacyclin exerts those beneficial effects in atheromatous arteries. New Zealand White Rabbits fed a 0.5% cholesterol diet underwent balloon injury and Palmaz-Schatz stent implantation in the iliac arteries followed PGIS gene (pCMV-PGIS, 200 microg) delivery by the lipotransfection method via Dispatch catheter (n=6 each). One week after transfection, arterial segments of pCMV-PGIS produced higher levels of 6-keto-PGF1alpha than those of control, pCMV-LacZ (p<0.05). The levels of vascular endothelial growth factor (VEGF) expression was greater in the vessels of pCMV-PGIS than in those of pCMV-LacZ demonstrated by immunohistochemical analysis and quantitation of Western blotting (1.8-fold, p<0.05). At 2 weeks, in-stent endothelialization was significantly greater in the vessels of pCMV-PGIS than in those of pCMV-LacZ (p<0.01). The percentage of BrdU-positive nuclei in the injured arterial segments was lower in vessels of pCMV-PGIS than pCMV-LacZ (p<0.01). At 4 weeks, PGIS gene transfer reduced the neointimal area by 38% (p<0.05) and widened the lumen area by 71% (p<0.01). PGIS gene transfer accelerated re-endothelialization, and attenuated neointimal formation after stent implantation in atheromatous rabbit arteries, at least in part, via increased production of VEGF protein.

P1776 A new method of prostacyclin synthase gene transfer ameliorates monocrotaline-induced pulmonary hypertension in rats

P1776 A new method of prostacyclin synthase gene transfer ameliorates monocrotaline-induced pulmonary hypertension in rats

Adenovirus mediated prostacyclin synthase gene transfer inhibits neointimal formation by modulating peroxisome proliferator-activated receptors expression

Adenovirus mediated prostacyclin synthase gene transfer inhibits neointimal formation by modulating peroxisome proliferator-activated receptors expression

Prostacyclin synthase gene transfer modulates cyclooxygenase-2-derived prostanoid synthesis and inhibits neointimal formation in rat balloon-injured arteries.

Previous studies have shown that prostacyclin (PGI(2)) synthase (PCS) gene transfer inhibits neointimal formation in balloon-injured arteries. However, the role of each cyclooxygenase (COX) isoform in this healing mechanism remains unknown. We hypothesized that overexpression of PCS may modulate COX-2-mediated prostaglandin (PG) metabolism. That is to say, excessive PGH(2) derived from COX-2 after balloon injury may be converted into PGI(2) rather than PGE(2) or thromboxane (TX) A(2) by overexpressed PCS. We examined the expression of COX isoforms and evaluated the role of COX-2 with regard to the effects of PCS gene transfer by using 4-(4-cyclohexyl-2-methyloxazol-5-yl)-2-fluorobenzenesulfonamide (JTE-522), a selective COX-2 inhibitor. Rats were divided into 4 groups in conjunction with PCS gene transfer and JTE-522 treatment. The PCS gene (30 microg) was transfected into rat balloon-injured arteries by a lipotransfection method. JTE-522 (30 mg/kg per day) was administered for 14 days after balloon injury. Immunohistochemical analysis demonstrated marked COX-2 expression on the neointima. PCS gene transfer markedly inhibited neointimal formation, but JTE-522 reversed this beneficial effect. PCS gene transfer augmented PGI(2) production and decreased PGE(2) production without affecting TXA(2) production, but JTE-522 inhibited this increase in PGI(2) production. In conclusion, PCS gene transfer modulated COX-2-mediated prostanoid synthesis and inhibited neointimal formation after balloon injury.

Prostacyclin synthase gene transfer inhibits neointimal formation in rat balloon injured arteries: The possible involvement of cyclooxygenase-2(COX-2) Michiharu Yamada, Yasushi Numaguchi, Mitsunori Harada, Hideo Matsui, Kenji Okumura. Nagoya University School of Medicine, Nagoya, Japan

Prostacyclin synthase gene transfer inhibits neointimal formation in rat balloon injured arteries: The possible involvement of cyclooxygenase-2(COX-2) Michiharu Yamada, Yasushi Numaguchi, Mitsunori Harada, Hideo Matsui, Kenji Okumura. Nagoya University School of Medicine, Nagoya, Japan

Prostacyclin synthase gene transfer inhibits neointimal formation in rat balloon-injured arteries without bleeding complications.

This study was designed to compare the effects of prostacyclin synthase (PCS) gene transfer with those of a systemic infusion of beraprost sodium (BPS), a prostacyclin analogue, on vascular smooth muscle cell (VSMC) proliferation and neointimal formation after arterial injury. PCS gene (3 or 30 micrograms) was transfected into rat balloon-injured carotid arteries by a non-viral lipotransfection method. BPS (100 or 300 micrograms/kg/day) was subcutaneously infused with osmotic pumps after the injury. LacZ gene (30 micrograms) was used as a control. VSMC proliferation was estimated by the bromodeoxyuridine (BrdU) index (BrdU-positive nuclei/total nuclei) at day 7. Neointimal formation was evaluated at day 14. Each treatment group had six rats. PCS gene transfer prevented the increase in intimal/medial area ratio (3 micrograms: 46.6%, 30 micrograms: 61.1% reduction; P < 0.05, P < 0.01, respectively), as did BPS 300 micrograms/kg/day (49.8% reduction; P < 0.05). BPS 100 micrograms/kg/day, however, had no effects on the ratio. PCS gene transfer and BPS 300 micrograms/kg/day significantly suppressed the BrdU index. BPS 300 micrograms/kg/day group had more frequent hematoma and longer bleeding time. There were no significant differences in blood pressure, heart rate, or urinary volume among all groups. Both PCS gene transfer and BPS 300 micrograms/kg/day reduced neointimal formation after arterial injury by inhibiting VSMC proliferation. PCS gene transfer may be a safer therapeutic modality against neointimal formation than a systemic infusion of BPS because the former method resulted in fewer bleeding complications.

Prostacyclin synthase gene transfer accelerates reendothelialization and inhibits neointimal formation in rat carotid arteries after balloon injury.

Prostacyclin (PGI2), a metabolite of arachidonic acid, has the vasoprotective effects of vasodilation, anti-platelet aggregation, and inhibition of smooth muscle cell proliferation. We hypothesized that an overexpression of endogenous PGI2 may accelerate the recovery from endothelial damage and inhibit neointimal formation in the injured artery. To test this hypothesis, we investigated in vivo transfer of the PGI2 synthase (PCS) gene into balloon-injured rat carotid arteries by a nonviral lipotransfection method. Seven days after transfection, a significant regeneration of endothelium was observed in the arteries transfected with a plasmid carrying the rat PCS gene (pCMV-PCS), but little regeneration was seen in those with the control plasmid carrying the lacZ gene (pCMV-lacZ) (percent luminal circumference lined by newly regenerated endothelium: 87. 1+/-6.9% in pCMV-PCS-transfected vessels and 6.9+/-0.2% in pCMV-lacZ vessels, P<0.001). BrdU staining of arterial segments demonstrated a significantly lower incorporation in pCMV-PCS-transfected vessels (7. 5+/-0.3% positive nuclei in vessel cells) than in pCMV-lacZ (50. 7+/-9.6%, P<0.01). Moreover, 2 weeks after transfection, the PCS gene transfer resulted in a significant inhibition of neointimal formation (88% reduction in ratio of intima/media areas), whereas medial area was similar among the groups. Arterial segments transfected with pCMV-PCS produced significantly higher levels of 6-keto-PGF1alpha, the main metabolite of PGI2, compared with the segments transfected with pCMV-lacZ (10.2+/-0.55 and 2.1+/-0.32 ng/mg tissue for pCMV-PCS and pCMV-placZ, P<0.001). In conclusion, this study demonstrated that an in vivo PCS gene transfer increased the production of PGI2 and markedly inhibited neointimal formation with accelerated reendothelialization in rat carotid arteries after balloon injury.