Protective Effect Of Prostaglandin E2 Research Articles

Prostaglandin E1 attenuates AngII-induced cardiac hypertrophy via EP3 receptor activation and Netrin-1upregulation

Abstract Aims Pathological cardiac hypertrophy induced by activation of the renin–angiotensin–aldosterone system (RAAS) is one of the leading causes of heart failure. However, in current clinical practice, the strategy for targeting the RAAS is not sufficient to reverse hypertrophy. Here, we investigated the effect of prostaglandin E1 (PGE1) on angiotensin II (AngII)-induced cardiac hypertrophy and potential molecular mechanisms underlying the effect. Methods and results Adult male C57 mice were continuously infused with AngII or saline and treated daily with PGE1 or vehicle for two weeks. Neonatal rat cardiomyocytes were cultured to detect AngII-induced hypertrophic responses. We found that PGE1 ameliorated AngII-induced cardiac hypertrophy both in vivo and in vitro. The RNA sequencing (RNA-seq) and expression pattern analysis results suggest that Netrin-1 (Ntn1) is the specific target gene of PGE1. The protective effect of PGE1 was eliminated after knockdown of Ntn1. Moreover, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the PGE1-mediated signaling pathway changes are associated with the mitogen-activated protein kinase (MAPK) pathway. PGE1 suppressed AngII-induced activation of the MAPK signaling pathway, and such an effect was attenuated by Ntn1 knockdown. Blockade of MAPK signaling rescued the phenotype of cardiomyocytes caused by Ntn1 knockdown, indicating that MAPK signaling may act as the downstream effector of Ntn1. Furthermore, inhibition of the E prostanoid (EP)3 receptor, as opposed to the EP1, EP2, or EP4 receptor, in cardiomyocytes reversed the effect of PGE1, and activation of EP3 by sulprostone, a specific agonist, mimicked the effect of PGE1. Conclusion In conclusion, PGE1 ameliorates AngII-induced cardiac hypertrophy through activation of the EP3 receptor and upregulation of Ntn1, which inhibits the downstream MAPK signaling pathway. Thus, targeting EP3, as well as the Ntn1–MAPK axis, may represent a novel approach for treating pathological cardiac hypertrophy. Funding Acknowledgement Type of funding sources: None.

Prostaglandin E1 attenuates AngII-induced cardiac hypertrophy via EP3 receptor activation and Netrin-1upregulation

AimsPathological cardiac hypertrophy induced by activation of the renin–angiotensin–aldosterone system (RAAS) is one of the leading causes of heart failure. However, in current clinical practice, the strategy for targeting the RAAS is not sufficient to reverse hypertrophy. Here, we investigated the effect of prostaglandin E1 (PGE1) on angiotensin II (AngII)-induced cardiac hypertrophy and potential molecular mechanisms underlying the effect. Methods and resultsAdult male C57 mice were continuously infused with AngII or saline and treated daily with PGE1 or vehicle for two weeks. Neonatal rat cardiomyocytes were cultured to detect AngII-induced hypertrophic responses. We found that PGE1 ameliorated AngII-induced cardiac hypertrophy both in vivo and in vitro. The RNA sequencing (RNA-seq) and expression pattern analysis results suggest that Netrin-1 (Ntn1) is the specific target gene of PGE1. The protective effect of PGE1 was eliminated after knockdown of Ntn1. Moreover, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the PGE1-mediated signaling pathway changes are associated with the mitogen-activated protein kinase (MAPK) pathway. PGE1 suppressed AngII-induced activation of the MAPK signaling pathway, and such an effect was attenuated by Ntn1 knockdown. Blockade of MAPK signaling rescued the phenotype of cardiomyocytes caused by Ntn1 knockdown, indicating that MAPK signaling may act as the downstream effector of Ntn1. Furthermore, inhibition of the E-prostanoid (EP) 3 receptor, as opposed to the EP1, EP2, or EP4 receptor, in cardiomyocytes reversed the effect of PGE1, and activation of EP3 by sulprostone, a specific agonist, mimicked the effect of PGE1. ConclusionIn conclusion, PGE1 ameliorates AngII-induced cardiac hypertrophy through activation of the EP3 receptor and upregulation of Ntn1, which inhibits the downstream MAPK signaling pathway. Thus, targeting EP3, as well as the Ntn1–MAPK axis, may represent a novel approach for treating pathological cardiac hypertrophy.

Prostaglandin E1 attenuates post‑cardiac arrest myocardial dysfunction through inhibition of mitochondria‑mediated cardiomyocyte apoptosis.

Post-cardiac arrest myocardial dysfunction (PAMD) is a leading cause of death in patients undergoing resuscitation patients following cardiac arrest (CA). Although prostaglandin E1 (PGE1) is a clinical drug used to mitigate ischemia injury, its effect on PAMD remains unknown. In the present study, the protective effects of PGE1 on PAMD were evaluated in a rat model of CA and in a hypoxia-reoxygenation (H/R) in vitro model. Rats were randomly assigned to CA, CA+PGE1 or sham groups. Asphyxia for 8 min followed by cardiopulmonary resuscitation were performed in the CA and CA+PGE1 groups. PGE1 was intravenously administered at the onset of return of spontaneous circulation (ROSC). PGE1 treatment significantly increased the ejection fraction and cardiac output within 4 h following ROSC and improved the survival rate, compared with the CA group. Moreover, PGE1 inactivated GSK3β, prevented mitochondrial permeability transition pore (mPTP) opening, while reducing cytochrome c and cleaved caspase-3 expression, as well as cardiomyocyte apoptosis in the rat model. To examine the underlying mechanism, H/R H9c2 cells were treated with PGE1 at the start of reoxygenation. The changes in GSK3β activity, mPTP opening, cytochrome c and cleaved caspase-3 expression, and apoptosis of H9c2 cells were consistent with those noted in vivo. The results indicated that PGE1 attenuated PAMD by inhibiting mitochondria-mediated cardiomyocyte apoptosis.

Prostaglandin E1 protects hepatocytes against endoplasmic reticulum stress-induced apoptosis via protein kinase A-dependent induction of glucose-regulated protein 78 expression.

AIMTo investigate the protective effect of prostaglandin E1 (PGE1) against endoplasmic reticulum (ER) stress-induced hepatocyte apoptosis, and to explore its underlying mechanisms.METHODSThapsigargin (TG) was used to induce ER stress in the human hepatic cell line L02 and hepatocarcinoma-derived cell line HepG2. To evaluate the effects of PGE1 on TG-induced apoptosis, PGE1 was used an hour prior to TG treatment. Activation of unfolded protein response signaling pathways were detected by western blotting and quantitative real-time RT-PCR. Apoptotic index and cell viability of L02 cells and HepG2 cells were determined with flow cytometry and MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] assay.RESULTSPretreatment with 1 μmol/L PGE1 protected against TG-induced apoptosis in both L02 cells and HepG2 cells. PGE1 enhanced the TG-induced expression of C/EBP homologous protein (CHOP), glucose-regulated protein (GRP) 78 and spliced X box-binding protein 1 at 6 h. However, it attenuated their expressions after 24 h. PGE1 alone induced protein and mRNA expressions of GRP78; PGE1 also induced protein expression of DNA damage-inducible gene 34 and inhibited the expressions of phospho-PKR-like ER kinase, phospho-eukaryotic initiation factor 2α and CHOP. Treatment with protein kinase A (PKA)-inhibitor H89 or KT5720 blocked PGE1-induced up-regulation of GRP78. Further, the cytoprotective effect of PGE1 on hepatocytes was not observed after blockade of GRP78 expression by H89 or small interfering RNA specifically targeted against human GRP78.CONCLUSIONOur study demonstrates that PGE1 protects against ER stress-induced hepatocyte apoptosis via PKA pathway-dependent induction of GRP78 expression.

The protective effects of prostaglandin E1 on lung injury following renal ischemia–reperfusion in rats

For the purposes of the present study, the protective effect of prostaglandin E1 (PGE1) on lung injury following renal ischemia-reperfusion (RIR) was investigated. Adult male rats were divided into four groups, namely, (I) control rats given physiological saline; (II) rats given PGE1 (20 μg/kg, intravenously); (III) rats subjected to RIR; and (IV) rats subjected to RIR given PGE1 30 min prior to ischemia and just before reperfusion. The right nephrectomy was performed in the RIR model. The left renal pedicle was occluded for 60 min to induce ischemia and then the left kidney was subjected to reperfusion for 60 min. The lungs of rats were used for microscopic and biochemical analyses. Although rats subjected to RIR did not exhibit heavy degenerative alterations in the lung structure, they possessed pulmonary interstitial edema. Lung glutathione levels and catalase, superoxide dismutase, glutathione peroxidase, and tissue factor (TF) activities were decreased in rats subjected to RIR, while lung lipid peroxidation, myeloperoxidase (MPO), xanthine oxidase and serum lactate dehydrogenase (LDH) activities, and blood urea and serum creatinine levels were increased in these rats when compared with the control group. PGE1 treatments resulted in the regression of oxidative stress via induction of antioxidant system, the decreased MPO and LDH activities, the reduced urea and creatinine levels, and the induced TF activity in rats subjected to RIR, while edema still remained permanent. We conclude that PGE1 may be useful in preventing lung injury with the exception of edema that occurred as a result of RIR in rats.

Prostaglandin-E1 has a protective effect on renal ischemia/reperfusion-induced oxidative stress and inflammation mediated gastric damage in rats

Gastrointestinal complications are frequent in renal transplant recipients. In this regard, renal ischemia/reperfusion injury (IRI)-induced gastric damage seems to be important and there is no data available on the mechanism of this pathology. Because of its anti-inflammatory and anti-oxidant properties, it can be suggested that prostaglandin-E1 (PGE1) protects cells from renal IRI-induced gastric damage. The aim of this study was to investigate the molecular mechanisms of gastric damage induced by renal IRI and the effect of PGE1 on these mechanisms. We set an experiment with four different animal groups: physiological saline-injected and sham-operated rats, PGE1 (20μg/kg)-administered and sham operated rats, renal IRI subjected rats, and PGE1-administered and renal IRI subjected rats. The protective effect of PGE1 on renal IRI-induced gastric damage was determined based on reduced histological damage and lactate dehydrogenase activity. Moreover, we demonstrated that PGE1 shows its protective effect through reducing the production of reactive oxygen species and malondialdehyde levels. During histological examination, we observed the presence of common mononuclear cell infiltration. Therefore, pro-inflammatory cytokines tumor necrosis factor-α and interleukin-1β levels were measured and it has been shown that PGE1 suppressed both cytokines. Furthermore, it was found that PGE1 reduced the number of NF-κB+ and caspase-3+ inflammatory cells, and also NF-κB DNA-binding activity, while increasing proliferating cell nuclear antigen+ epithelial cells in the stomach tissue of rats subjected to renal IR. Our data showed that PGE1 has a protective effect on renal IRI-induced oxidative stress and inflammation mediated gastric damage in rats.

Activation of the Prostaglandin E2 receptor EP2 prevents house dust mite-induced airway hyperresponsiveness and inflammation by restraining mast cells' activity.

Prostaglandin E2 (PGE2 ) has been proposed to exert antiasthmatic effects in patients, to prevent antigen-induced airway pathology in murine models, and to inhibit mast cells (MC) activity invitro. To assess in a murine model whether the protective effect of PGE2 may be a consequence of its ability to activate the E-prostanoid (EP)2 receptor on airway MC. Either BALB/c or C57BL/6 mice were exposed intranasally (i.n.) to house dust mite (HDM) aeroallergens. Both strains were given PGE2 locally (0.3mg/kg), but only BALB/c mice were administered butaprost (EP2 agonist: 0.3mg/kg), or AH6809 (EP2 antagonist; 2.5mg/kg) combined with the MC stabilizer sodium cromoglycate (SCG: 25mg/kg). Airway hyperresponsiveness (AHR) and inflammation, along with lung MC activity, were evaluated. In addition, butaprost's effect was assessed in MC-mediated passive cutaneous anaphylaxis (PCA) in mice challenged with 2,4-dinitrophenol (DNP). Selective EP2 agonism attenuated aeroallergen-caused AHR and inflammation in HDM-exposed BALB/c mice, and this correlated with a reduced lung MC activity. Accordingly, the blockade of endogenous PGE2 by means of AH6809 worsened airway responsiveness in sensitive BALB/c mice, and such worsening was reversed by SCG. The relevance of MC to PGE2 -EP2 driven protection was further highlighted in MC-dependent PCA, where butaprost fully prevented MC-induced ear swelling. Unlike in BALB/c mice, PGE2 did not protect the airways of HDM-sensitized C57BL/6 animals, a strain in which we showed MC to be irrelevant to aeroallergen-driven AHR and inflammation. The beneficial effect of both exogenous and endogenous PGE2 in aeroallergen-sensitized mice may be attributable to the activation of the EP2 receptor, which in turn acts as a restrainer of airway MC activity. This opens a path towards the identification of therapeutic targets against asthma along the 'EP2 -MC-airway' axis.

Does prostaglandin-E1 modulate d-galactosamine induced cell death in primary culture of human hepatocytes?

Background: Cell death pathway can occur under physiological or pathological conditions. In vitro and in vivo studies have shown that d-galactosamine (DGA) induces hepatocyte damage. Objective: The present study aims to evaluate the protective effect of prostaglandin E1 (PGE1) on DGA-induced apoptosis, necrosis and oxidative stress in primary culture of human hepatocytes. Methods: Normal human hepatocytes were obtained from the safety margin of liver specimens, removed during hepatectomy operation to liver cancer patients, and isolated using the classical collagenase perfusion method. After culture stabilization, PGE1 (1μM) was added 2h before DGA (5mM). Cultures were maintained for 24h before the parameters for apoptosis, necrosis and oxidative stress were measured. Apoptosis was studied by DNA-fragmentation, neutral (nSMase) and acid (aSMase) sphingomyelinase and caspase-3 activity. Necrosis was investigated by lactate dehydrogenase (LDH) and transaminases (ALT & AST) enzymes. The oxidative stress was assessed by malondialdehyde (MDA), glutathione (GSH), oxidized glutathione (GSSH), glutathione S-transferase (GST), glutathione peroxidase (GSPx), catalase (CAT), superoxide dismutase (SOD) and nitric oxide (NO). Results: The hepatotoxin DGA induced apoptosis and enhanced all parameters related to necrosis and intracellular oxidative stress. On the other hand, PGE1 reduced the measured values for the parameters indicative for the DAG induced apoptosis, necrosis and oxidative stress. In addition, PGE1 proved also to prevent GSH depletion. The obtained results provided evidences for the biochemical hepatotoxic effects of DGA (5mM) especially through the induction of apoptosis, necrosis and oxidative stress alterations in the cultured human hepatocytes. Conclusion: PGE1 could be a useful protective treatment against DGA-induced hepatocyte cell death.

Prophylactic effects of prostaglandin E2 on NSAID-induced enteropathy-role of EP4 receptors in its protective and healing-promoting effects.

Prostaglandin E2 not only prevents NSAID-generated small intestinal lesions, but also promotes their healing. The protective effects of prostaglandin E2 are mediated by the activation of EP4 receptors and functionally associated with the stimulation of mucus/fluid secretions and inhibition of intestinal hypermotility, resulting in the suppression of enterobacterial invasion and iNOS up-regulation, which consequently prevents intestinal lesions. Prostaglandin E2 also promotes the healing of intestinal damage by stimulating angiogenesis through the up-regulation of VEGF expression via the activation of EP4 receptors. These findings have contributed to a further understanding of the mechanisms responsible for 'protective' and 'healing-promoting' effects of prostaglandin E2 and the development of new strategies for the prophylactic treatment of NSAID-induced enteropathy.

Protective Effect of Prostaglandin E1 on Renal Microvascular Injury in Rats of Acute Aristolochic Acid Nephropathy

Background: To investigate the renal microvascular injury in acute aristolochic acid nephropathy (AAN) and the protective effects of prostaglandin E1 (PGE1) in acute AAN. Methods: Female Sprague–Dawley rats were randomly divided into three groups. The rats in PGE1 group received Caulis Aristolochia manshuriensis (CAM) decoction by gavage for 5 days, and PGE1 was given by vena caudalis before gavage. The rats in model group were gavaged with CAM for 5 days, and the same dose of 0.9% physiologic saline was given by vena caudalis. The rats in control group only received an equal daily volume of saline solution by gavage. Animals were killed at days 3, 5, and 7. Blood urea nitrogen (BUN), serum creatinine, and urinary protein were monitored before killing. Microvascular density was determined by JG12 immunostaining. The expression of angiogenic factor was assessed by vascular endothelial growth factor (VEGF). Tubulointerstitial hypoxia was assessed by hypoxia-inducible factor-1α (HIF-1α) expression. Results: CAM induced a significant decrease in VEGF expression and microvascular density in the kidney tissue, accompanied by a significant increase in HIF-1α, which reduced renal function and increased 24-h urinary protein excretion rates. PGE1 lessened the capillary loss, relieved hypoxia, and protected renal function. No significant pathological changes were found in control rats. Conclusion: The renal microvascular injury in acute AAN is severe. PGE1 can significantly ameliorate the renal microvascular injury, relieve hypoxia, and protect renal function.

Protective effects of prostaglandin E1 on human umbilical vein endothelial cell injury induced by hydrogen peroxide

To investigate the protective effects of prostaglandin E(1) (PGE(1)) against H(2)O(2)-induced oxidative damage on human umbilical vein endothelial cells (HUVECs). HUVECs were pretreated with PGE(1) (0.25, 0.50, and 1.00 micromol/L) for 24 h and exposed to H(2)O(2) (200 micromol/L) for 12 h, and cell viability was measured by the MTT assay. LDH, NO, SOD, GSH-Px, MDA, ROS, and apoptotic percentage were determined. eNOS expression was measured by Western blotting and real-time PCR. PGE(1) (0.25-1.00 micromol/L) was able to markedly restore the viability of HUVECs under oxidative stress, and scavenged intracellular reactive oxygen species induced by H(2)O(2). PGE(1) also suppressed the production of lipid peroxides, such as MDA, restored the activities of endogenous antioxidants including SOD and GSH-Px, and inhibited cell apoptosis. In addition, PGE(1) significantly increased NO content, eNOS protein, and mRNA expression. PGE(1) effectively protected endothelial cells against oxidative stress induced by H(2)O(2), an activity that might depend on the up-regulation of NO expression.

COX2 inhibitors for acquired brain injuries: Is the time ripe?*

The timeliness of the results presented in “Cyclooxygenase-2 inhibition provides lasting protection against neonatal hypoxic-ischemic brain injury” by Fathali et al (1) pertains to our current lack of treatments for improving functional deficits after acquired brain injuries. Fathali and colleagues examine the relationships between perinatal hypoxic/ ischemic brain injury, COX2 inhibition, and functional recovery, brain/body morphometrics, and the inflammatory response induced after hypoxic brain injury in neonatal rats. This work provides the basis for a better understanding of the molecular effectors of neuroinflammation, and the effects of COX2 inhibitors (coxibs) on those effectors. The results show an increase in COX2 after brain injury that could be reversed by early posthypoxia intervention with superanalgesic doses of the COX2 inhibitor NS-398. Consistent with other neuroprotection studies, this high-dose regimen reduced subacute mortality from hypoxic/ischemic insult, stabilized chronic brain and body weight loss, and improved functional recovery in both neurologic and cognitive testing paradigms. The evidence that prolonged elevations of COX2 expression and activity in the brain is detrimental to outcomes is overwhelming reviewed in our earlier work (2). The induction by and contribution of COX2 to inflammation in the brain has been well documented (3–5). However, there may be a case for an initial benefit of the acute COX2 response. In our brain injury studies, some data indicated (albeit indirectly) that acute COX2 activity may be beneficial (6). A few studies suggested prostaglandins may be neuroprotective, but the preponderance of data show the opposite. The effects of prostaglandin E2 in neural excitotoxicity models are limited to subacute reductions in nuclear dye uptake; no protection was seen after 48 hrs (7). McCullough et al showed that the protective effects of prostaglandin E2 in primarily neuronal cell cultures diminished significantly in cultured brain slices, likely because of the preservation of astrocytic/neuronal interactions in organotypic cultures (8). Prostaglandin E2, likely via the EP2 receptor, mediates reduced neuroinflammatory responses in cultured neurons, but not in the presence of glia (8). Interestingly, one study has provided evidence that COX2 prostaglandins, rather than reactive oxygen species, are responsible for COX2-mediated neurotoxicity (9). Importantly, the studies in which prostanoids (or their EP2 receptors) are characterized as neuroprotective have never shown improvements in functional outcomes. By contrast, COX2 inhibitors (e.g., 5,5-dimethyl-3-(3-fluorophenyl)-4-(4-methylsulphonyl)phenyl-2(5H)-furanone [DFU] and nimesulide) reduced inflammation and cell death, and improved behavioral recovery even when administered hours after brain injury (6, 10–12). These findings provide evidence that COX2 inhibitors have an extended window of opportunity to protect vulnerable brain tissue from secondary damage. Furthermore, our studies suggest that coxibs do more than just reduce prostaglandins and free radicals. COX2 inhibition after brain injury causes arachidonic acid shunting, increasing hydroxyeicosatetraenoic acids and epoxyeicosatrienoic acids levels in the injured brain (6, 13). These cytochrome P450 epoxygenase metabolites of arachidonic acid are prime candidates for neuroprotective eicosanoids. Hydroxyeicosatetraenoic acids have been shown to block glutamate-mediated excitotoxicity in cultured neurons (14). Epoxyeicosatrienoic acids block activation of inflammatory gene induction and reduce adhesion molecule expression in endothelial cells both in vitro and in vivo (15). It is apparent from this study by Fathali et al (1) that there are minimal age-related differences in the benefit of coxibs to the injured brain. The coxib-related risks of adverse cardiovascular events (16–21) are containable, if not in-significant, in the perinatal population. Thus, this work also represents a potential therapeutic approach after perinatal hypoxia that could improve the quality of life for children and their families. Yet, the lack of treatments to block COX2 or its induction specifically after brain injury is due, in my opinion, to a popular collective expectation in this country of a life free from risk, rather than to any failings of researchers to provide proof-of-principle or in BioPharma’s considerable efforts to develop and make available helpful tools for this indication. There are still critical questions that remain with regard to the coxibs’ mechanisms of action, or whether there is any gender dependence in their utility (or risk of adverse effects). But if the current beneficial use of thalidomide after decades of disuse (due, admittedly, to its dreadful side effects on human fetuses) is any example, it will be a long time before drugs like rofecoxib or parecoxib can be revived. Only a grass-roots consciousness-raising effort by professional and patient advocates can change the repetition of a long, long wait for these potentially valuable agents in the treatment of brain injuries.

DG-041 inhibits the EP3 prostanoid receptor—A new target for inhibition of platelet function in atherothrombotic disease

Receptors for prostanoids on platelets include the EP3 receptor for which the natural agonist is the inflammatory mediator prostaglandin E2 (PGE2) produced in atherosclerotic plaques. EP3 is implicated in atherothrombosis and an EP3 antagonist might provide atherosclerotic lesion-specific antithrombotic therapy. DG-041 (2,3-dichlorothiophene-5-sulfonic acid, 3-[1-(2,4-dichlorobenzyl)-5-fluoro-3-methyl-1H-indol-7-yl]acryloylamide) is a direct-acting EP3 antagonist currently being evaluated in Phase 2 clinical trials. We have examined the contributions of EP3 to platelet function using the selective EP3 agonist sulprostone and also PGE2, and determined the effects of DG-041 on these. Studies were in human platelet-rich plasma or whole blood and included aggregometry and flow cytometry. Sulprostone enhanced aggregation induced by primary agonists including collagen, TRAP, platelet activating factor, U46619, serotonin and adenosine diphosphate, and enhanced P-selectin expression and platelet–leukocyte conjugate formation. It inhibited adenylate cyclase (measured by vasodilator-stimulated phosphoprotein phosphorylation) and enhanced Ca2+ mobilization. It potentiated platelet function even in the presence of aspirin and/or AR-C69931 (a P2Y12 antagonist). DG-041 antagonized the effects of sulprostone on platelet function. The effect of PGE2 on platelet aggregation depended on the nature of the agonist and the concentration of PGE2 used as a consequence of both pro-aggregatory effects via EP3 and anti-aggregatory effects via other receptors. DG-041 potentiated the protective effects of PGE2 on platelet aggregation by inhibiting the pro-aggregatory effect via EP3 stimulation. DG-041 remained effective in the presence of a P2Y12 antagonist and aspirin. DG-041 warrants continued investigation as a potential agent for the treatment of atherothrombosis without inducing unwanted bleeding risk.

Protective effect of prostaglandin E1 on renal function of rats after liver transplantation

目的 探讨术中应用前列腺素E1(prostaglandin E1,PGE1)对大鼠肝移植肾功能的保护作用.方法 大鼠原位肝移植术中经颈内静脉灌注PGE1为治疗组,生理盐水和空白为对照组,观察术后1周存活率、1 h的尿量,测定血浆肌酐、尿素氮和肾组织中丙二醛(malondialdehyde,MDA)、谷胱甘肽(glutathione,GSH)含量,肾组织病理检查.结果 PGE1治疗组术后1 h尿量较对照组明显增加,肌酐和尿素氮水平均较对照组降低,PGE1治疗组肾组织中GSH含量显著高于两对照组,MDA含量低于两对照组.病理检查PGE1治疗组肾脏组织形态学损伤明显减轻.结论 术中应用PGE1能显著改善大鼠肝移植后的肾功能,其机制可能与对抗氧自由基损伤作用有关。

Pharmacologic Preconditioning Effects: Prostaglandin E 1 Induces Heat-Shock Proteins Immediately After Ischemia/Reperfusion of the Mouse Liver

Prostaglandin E1 (PGE1) has several potential therapeutic effects, including cytoprotection, vasodilation, and inhibition of platelet aggregation. This study investigates the protective action of PGE1 against hepatic ischemia/reperfusion injury in vivo using a complementary DNA microarray. PGE1 or saline was continuously administered intravenously to mice in which the left lobe of the liver was made ischemic for 30 minutes and then reperfused. Livers were harvested 0, 10, and 30 minutes postreperfusion. Messenger RNA was extracted, and the samples were labeled with two different fluorescent dyes and hybridized to the RIKEN set of 18,816 full-length enriched mouse complementary DNA microarrays. Serum alanine aminotransferase and aspartate aminotransferase levels at 180 minutes postreperfusion were significantly lower in the PGE1-treated group than in the saline-treated group. The cDNA microarray analysis revealed that the genes encoding heat-shock protein (HSP) 70, glucose-regulated protein 78, HSP86, and glutathione S-transferase were upregulated at the end of the ischemic period (0 minutes postreperfusion) in the PGE1 group. Our results suggested that PGE1 induces HSPs immediately after ischemia reperfusion. HSPs might therefore play an important role in the protective effects of PGE1 against ischemia/reperfusion injury of the liver.

Protective effect of prostaglandin E1 against ischemia of spinal cord during aortic cross clamping.

The purpose of this study was to investigate whether or not 5-minute segmental intraaortic perfusion of prostaglandin E1 (PGE1) in the preischemic period has a protective effect against spinal cord ischemia during aortic cross clamping. The rabbits were divided into two groups. In group A (n = 6), the infrarenal aorta was segmentally cross clamped and the segment was perfused for 5 minutes with blood and saline solution at first. The aorta was kept cross clamped without perfusion for a subsequent 20 minutes. In group B (n = 6), the infrarenal aorta was segmentally cross clamped and the segment was perfused for 5 minutes with blood and saline solution containing PGE1 of 100 ng/kg/min at first. The aorta was kept cross clamped without perfusion for a subsequent 20 minutes. After the aorta was declamped, the experimental animals recovered from the anesthesia. Twenty-four and 48 hours after the operation, the hind limb function was estimated with Tarlov's grade. Then, the animals were killed for pathologic study. The systolic arterial pressures measured at the left common carotid artery through the experiment were not significantly different between the two groups. The perfusion of the aortic segment between the proximal and distal clamp was nonpulsatile. The perfusion pressures of the aortic segments at 5 minutes after aortic cross clamping were 29 +/- 6 mm Hg and 33 +/- 6 mm Hg in groups A and B, respectively. No significant differences were seen between the two groups. In group A, the hind limb functions evaluated with Tarlov's grade after 24 hours and 48 hours were 0 to 3 (1.5 +/- 1.4) and 0 to 3 (1.3 +/- 1.4), respectively. In group B, these were 3 to 4 (3.5 +/- 0.5) and 3 to 4 (3.7 +/- 0.5), respectively. A significant difference was seen between the two groups (P <.05). In the ventral horn of the L5, L6, and L7 segments, large motor neurons that seemed viable were more preserved in group B than in group A. Segmental intraaortic perfusion of PGE1 in the preischemic period reduced neurologic damage of spinal cord ischemia.

Tumour necrosis factor-alpha and nitric oxide mediate apoptosis by D-galactosamine in a primary culture of rat hepatocytes: exacerbation of cell death by cocultured Kupffer cells.

Prostaglandin E1 (PGE1) reduces cell death in experimental and clinical liver dysfunction. Whether PGE1 protects against D-galactosamine (D-GalN)-associated hepatocyte cell death by the regulation of tumour necrosis factor-alpha (TNF-alpha) and/or nitric oxide (NO) in hepatocytes or cocultured Kupffer cells was examined. Anti-TNF-alpha antibodies were used to evaluate the role of TNF-alpha during D-GalN cytotoxicity and its protection by PGE1 in cocultured hepatocytes and Kupffer cells. Cell apoptosis and necrosis were assessed by DNA fragmentation and lactate dehydrogenase release, respectively. Nitrite+nitrate (NOx), as NO end products, and TNF-alpha concentrations were measured in the culture medium. The role of NO was determined by measuring inducible NO synthase (iNOS) expression and the effect of its inhibition during d-GalN cytotoxicity and its protection by PGE1. D-GalN enhanced hepatocyte cell death associated with high TNF-alpha and NOx levels in a culture medium. Anti-TNF-alpha and iNOS inhibition suggested that TNF-alpha was mediating apoptosis, but not necrosis, through the stimulation of NO production. The antiapoptotic activity of PGE1 was associated with a reduction of NO production, but was blocked by iNOS inhibition. This apparent contradiction was explained by the ability of PGE1 to enhance iNOS expression shortly after its administration and inhibit it later during d-GalN treatment. Anti-TNF-alpha antibodies did not reduce the exacerbation of d-GalN-associated cell death in hepatocytes by cocultured Kupffer cells. TNF-alpha mediates D-GalN-induced apoptosis via NO production in cultured hepatocytes. The protective effect of PGE1 against D-GalN-induced apoptosis is probably through the induction of low iNOS expression that was followed by a reduction of iNOS expression and NO production induced by the hepatotoxin. The exacerbation of hepatocyte cell death by Kupffer cells was not related to TNF-alpha and NO.

Protective effects of prostaglandin E1 on hepatocytes.

Numerous studies have demonstrated the protective action of prostaglandin E1 (PGE1) on experimental animal models of liver injury and on patients with fulminant viral hepatitis. It could act on PGE1 receptor of the diseased vessels to dilate them and increase portal venous flow, improve the microcirculation of the liver, clear the metabolites of the liver cells, and increase oxygen supply to the liver tissues. PGE1 could also accumulate at the inflammentory por tion, inhibit the release of lethal factors, stablize the membrane of liver cell s and lysosome, inhibit the active oxygen, and promote the proliferation of the liver cells. It is now used to treat fulminant hepatic failure.

Protective effect of prostaglandin E1 against ischemia/reperfusion-induced liver injury: results of a prospective, randomized study in cirrhotic patients undergoing subsegmentectomy

Background/Aims: The cytoprotective effects of prostaglandin E1 on livers suffering from ischemia/reperfusion injury in the clinical setting are unproved. These effects were examined, focusing on inflammatory cytokine and nitric oxide metabolism. Methods: Twenty-four cirrhotic patients with hepatocellular carcinoma undergoing subsegmentectomy under ischemia induced only by Pringle's maneuver were divided into two groups (patients given prostaglandin E1 by injection and untreated controls) and postoperative results were compared. Peripheral blood was taken perioperatively and the plasma aminotransferase, cytokines and nitrate/nitrite levels of the two groups were compared. Two liver specimens were taken from each patient, one before ischemia and the other after hepatectomy, and the levels of inducible nitric oxide synthase and cytokine mRNAs and proteins were analyzed. Results: Although no apparent differences were recognized in postoperative complications or duration of postoperative hospital stay between the groups, the perioperative plasma aminotransferase level was significantly lower in the prostaglandin E1 group. Significant differences were also seen in interleukin-6 and nitrate plasma levels during the observation period and the interleukin-6 protein levels in the liver supernatants after hepatectomy in the two groups. In contrast, no significant differences were apparent between the interleukin-1 beta and tumor necrosis factor-alpha plasma levels of the two groups. The corrected fluorescence activities of interleukin-6 and inducible nitric oxide synthase mRNAs in the liver after hepatectomy correlated significantly. No interleukin-1 beta or tumor necrosis factor-alpha mRNAs or proteins were detected. Conclusions: Prostaglandin E1 exerted hepatoprotective effects on livers suffering from ischemia/reperfusion injury, and interleukin-6 might play an important role in these effects.

Cytotoxicity of Anti-Cancer Drugs to Vascular Endothelial Cells and Inhibitory Effect of PGE.

In this study, the degree of in vitro cytotoxicity of anticancer drugs, including 5-fluorouracil, doxorubicin, cis-diamminedi-chloroplatinum, and mitomycin C, to vascular endothelial cells collected from the carotid artery of cows was evaluated by the MTT (3-(4, 5-dimeth-ylthiazol-2-yl)-3, 5-Biphenyl tetrazolium bromide) assay. The results indicated that the viability of vascular endothelial cells decreased with the addition of all of the above anti-cancer drugs, and a positive correlation was found between cytotoxicity and the drug concentration, as well as between cytotoxicity and the length of incubation with the anti-cancer drugs. The cytotoxicity of doxorubicin, cis-diamminedichloroplatinum, and mitomycin C became evident very rapidly and was stronger than that of 5-fluorouracil. The protective effect of prostaglandin E1 on the cytotoxicity caused by anti-cancer drugs was examined. The results also indicated that the addition of prostaglandin E1 inhibited the decrease in the viability of vascular endothelial cells which had been induced by 5-fluorouracil. These findings suggested that anti-cancer drugs cause endothelial cell injury and that prostaglandin E1 can protect this type of injury at least when induced by 5-fluorouracil.