Aldo-keto reductase family member C3(AKR1C3)promotes hepatocellular carcinoma cell growth by producing prostaglandin F2α

Hepatocellular carcinoma(HCC)is a leading cause of death worldwide.Current therapies are effective for HCC patients with early disease,but many patients suffer recurrence after surgery and have a poor response to chemotherapy.Therefore,new therapeutic targets are needed.We analyzed gene expression profiles between HCC tissues and normal adjacent tissues from public databases and found that the expression of genes involved in lipid metabolism was significantly different.The analysis showed that AKR1C3 was upregulated in tumors,and high AKR1C3 expression was associated with a poorer prognosis in HCC patients.In vitro,assays demonstrated that the knockdown of AKR1C3 or the addition of the AKR1C3 inhibitor indomethacin suppressed the growth and colony formation of HCC cell lines.Knockdown of AKR1C3 in Huh7 cells reduced tumor growth in vivo.To explore the mechanism,we performed pathway enrichment analysis,and the results linked the expression of AKR1C3 with prostaglandin F2 alpha(PGF2a)downstream target genes.Suppression of AKR1C3 activity reduced the production of PGF2a,and supplementation with PGF2a restored the growth of indomethacin-treated Huh7 cells.Knockdown of the PGF receptor(PTGFR)and treatment with a PTGFR inhibitor significantly reduced HCC growth.We showed that indomethacin potentiated the sensitivity of Huh7 cells to sorafenib.In summary,our results indicate that AKR1C3 upregulation may promote HCC growth by promoting the production of PGF2α,and suppression of PTGFR limited HCC growth.Therefore,targeting the AKR1C3-PGF2a-PTGFR axis may be a new strategy for the treatment of HCC.

Prostaglandin E1 administration post liver transplantation and renal outcomes:A retrospective single center experience

BACKGROUND Prostaglandin E1(PGE1),or alprostadil,is a potent vasodilator that improves hepatic blood flow and reduces ischemia-reperfusion injury post-liver transplantation(LT).However,the benefits of PGE1 on renal function after LT have not yet been well described.AIM To assess the impact of PGE1 administration on renal function in patients who underwent liver or liver-kidney transplant.METHODS This retrospective study included all patients who underwent liver or liverkidney transplant at our institution from January,2011 to December,2021.Patients were classified based on whether they received PGE1.PGE1 was administered post-LT to those with transaminases>1000 U/L in the immediate postoperative period.Demographics,post-LT treatments and/or complications,renal function,and survival were analyzed.Multivariable logistic regression analysis was performed,and a two-tailed P value<0.05 was considered statistically significant.RESULTS A total of 145 patients underwent LT,with 44(30%)receiving PGE1.Baseline patient characteristics were comparable,except the PGE1 group had significantly higher aspartate aminotransferase(AST)(1961.9 U/L±1862.3 U/L vs 878 U/L±741.4 U/L,P=0.000),alanine aminotransferase(1070.6 U/L±895 U/L vs 547.7 U/L±410 U/L,P=0.000),international normalized ratio on post-LT day 1(2±0.74 vs 1.8±0.4,P=0.03),a longer intensive care unit stay(8.1 days±11.8 days vs 3.8 days±4.6 days,P=0.003),more vasopressor use(55.53 hours±111 hours vs 16.33 hours±26.3 hours,P=0.002),and higher immediate postoperative complications(18.6%vs 4.9%,P=0.04).The PGE1 group also had a significantly higher 90-day readmission rate(29.6%vs 13.1%,P=0.02)and lower 1-year liver graft survival(87.5%vs 98.9%,P=0.005).However,30-day readmission(31.6%vs 27.4%,P=0.64),LT complications(hepatic artery thrombosis,biliary complications,rejection of liver graft,cardiomyopathy),1-year patient survival(96.9%vs 97.8%,P=0.77),overall liver graft survival,and overall patient survival were similar between the two groups(95.4%vs 93.9%,P=0.74 and 88.4%vs 86.9%,P=0.81 respectively).Although the PGE1 group had a significantly lower glomerular filtration rate(eGFR)on post-LT day 7(46.3 mL/minute±26.7 mL/minute vs 62.5 mL/minute±34 mL/minute,P=0.009),the eventual need for renal replacement therapy(13.6%vs 5.9%,P=0.09),the number of dialysis sessions(0.91 vs 0.27,P=0.13),and eGFR at 1-month(37.2 mL/minute±35.9 mL/minute vs 42 mL/minute±36.9 mL/minute,P=0.49),6-months(54.8 mL/minute±21.6 mL/minute vs 62 mL/minute±21.4 mL/minute,P=0.09),and 12-months(63.7 mL/minute±20.7 mL/minute vs 62.8 mL/minute±20.3 mL/minute,P=0.85)post-LT were similar to those in the non-PGE1 group.CONCLUSION In patients who received PGE1 for ischemia-reperfusion injury,despite immediate acute renal injury post-LT,the renal function at 1-month,6-months,and 12-months post-LT was similar compared to those without ischemiareperfusion injury.Prospective clinical trials are needed to further elucidate the benefits of PGE1 use in renal function.

Prostaglandin F_(2α)synthase promotes oxaliplatin resistance in colorectal cancer through prostaglandin F_(2α)-dependent and F_(2α)-independent mechanism

BACKGROUND Oxaliplatin(Oxa)is the first-line chemotherapy drug for colorectal cancer(CRC),and Oxa resistance is crucial for treatment failure.Prostaglandin F_(2α)synthase(PGF 2α)(PGFS),an enzyme that catalyzes the production of PGF_(2α),is involved in the proliferation and growth of a variety of tumors.However,the role of PGFS in Oxa resistance in CRC remains unclear.AIM To explore the role and related mechanisms of PGFS in mediating Oxa resistance in CRC.METHODS The PGFS expression level was examined in 37 pairs of CRC tissues and paracancerous tissues at both the mRNA and protein levels.Overexpression or knockdown of PGFS was performed in CRC cell lines with acquired Oxa resistance(HCT116-OxR and HCT8-OxR)and their parental cell lines(HCT116 and HCT8)to assess its influence on cell proliferation,chemoresistance,apoptosis,and DNA damage.For determination of the underlying mechanisms,CRC cells were examined for platinum-DNA adducts and reactive oxygen species(ROS)levels in the presence of a PGFS inhibitor or its products.RESULTS Both the protein and mRNA levels of PGFS were increased in the 37 examined CRC tissues compared to the adjacent normal tissues.Oxa induced PGFS expression in the parental HCT116 and HCT8 cells in a dosedependent manner.Furthermore,overexpression of PGFS in parental CRC cells significantly attenuated Oxainduced proliferative suppression,apoptosis,and DNA damage.In contrast,knockdown of PGFS in Oxa-resistant HCT116 and HCT8 cells(HCT116-OxR and HCT8-OxR)accentuated the effect of Oxa treatment in vitro and in vivo.The addition of the PGFS inhibitor indomethacin enhanced the cytotoxicity caused by Oxa.Treatment with the PGFS-catalyzed product PGF_(2α)reversed the effect of PGFS knockdown on Oxa sensitivity.Interestingly,PGFS inhibited the formation of platinum-DNA adducts in a PGF_(2α)-independent manner.PGF_(2α)exerts its protective effect against DNA damage by reducing ROS levels.CONCLUSION PGFS promotes resistance to Oxa in CRC via both PGF_(2α)-dependent and PGF_(2α)-independent mechanisms.

The antioxidant trolox inhibits aging and enhances prostaglandin E-2 secretion in mesenchymal stem cells

Mesenchymal stem cells(MSCs)have been widely used in regenerative medicine and clinical therapy due to their capabilities of proliferation,differentiation,and immune regulation.However,during in vitro expansion,MSCs are prone to aging,which largely limits their application.Prostaglandin E-2(PGE-2)is a key effector secreted by MSCs to exert immunomodulatory effects.By screening the compound library for PGE-2 secretion,the antioxidant trolox was verified as a stimulator of MSCs to secrete PGE-2.The effect of antioxidant trolox on biological characteristics of MSCS,including aging,proliferation,and gene expression,was examined.The results demonstrated that trolox can resist aging,promote proliferation,and enhance PGE-2 secretion of MSCs without affecting their surface marker expression.Furthermore,trolox treatment up-regulates miR-17-92 clusters in MSCs and may contribute to its anti-aging effects.Thus,trolox addition might be beneficial for MSCs expansion and their application.

Intra-arterial lipo-prostaglandin E1 infusion for arterial spasm in liver transplantation:A case report

BACKGROUND Hepatic artery obstruction is a critical consideration in graft outcomes after living donor liver transplantation.We report a case of diffuse arterial vasospasm that developed immediately after anastomosis and was managed with an intra-arterial infusion of lipo-prostaglandin E1(PGE1).CASE SUMMARY A 57-year-old male with hepatitis B virus-related liver cirrhosis and hepatocellular carcinoma underwent ABO-incompatible living donor liver transplant.The grafted hepatic artery was first anastomosed to the recipient’s right hepatic artery stump.However,the arterial pulse immediately weakened.Although a new anastomosis was performed using the right gastroepiploic artery,the patient’s arterial pulse rate remained poor.We attempted angiographic intervention immediately after the operation;it showed diffuse arterial vasospasms like‘beads on a string’.We attempted continuous infusion of lipo-PGE1 overnight via an intra-arterial catheter.The next day,arterial flow improved without any spasms or strictures.The patient had no additional arterial complications or related sequelae at the time of writing,1-year post-liver transplantation.CONCLUSION Angiographic evaluation is helpful in cases of repetitive arterial obstruction,and intra-arterial infusion of lipo-PGE1 may be effective in treating diffuse arterial spasms.

Post-translational modifications of prostaglandin-endoperoxide synthase 2 in colorectal cancer:An update

The biosynthesis of prostanoids is involved in both physiological and pathological processes. The expression of prostaglandin-endoperoxide synthase 2(PTGS2; also known as COX-2) has been traditionally associated to the onset of several pathologies, from inflammation to cardiovascular, gastrointestinal and oncologic events. For this reason, the search of selective PTGS2 inhibitors has been a focus for therapeutic interventions. In addition to the classic non-steroidal anti-inflammatory drugs, selective and specific PTGS2 inhibitors, termed coxibs, have been generated and widely used. PTGS2 activity is less restrictive in terms of substrate specificity than the homeostatic counterpart PTGS1, and it accounts for the elevated prostanoid synthesis that accompanies several pathologies. The main regulation of PTGS2 occurs at the transcription level. In addition to this, the stability of the mRNA is finely regulated through the interaction with several cytoplasmic elements, ranging from specificmicroR NAs to proteins that control mR NA degradation. Moreover, the protein has been recognized to be the substrate for several post-translational modifications that affect both the enzyme activity and the targeting for degradation via proteasomal and non-proteasomal mechanisms. Among these modifications, phosphorylation, glycosylation and covalent modifications by reactive lipidic intermediates and by free radicals associated to the proinflammatory condition appear to be the main changes. Identification of these post-translational modifications is relevant to better understand the role of PTGS2 in several pathologies and to establish a correct analysis of the potential function of this protein in diseases progress. Finally, these modifications can be used as biomarkers to establish correlations with other parameters, including the immunomodulation dependent on molecular pathological epidemiology determinants, which may provide a better frame for potential therapeutic interventions.

Acetylsalicylic acid interferes with embryonic kidney growth and development by a prostaglandin-independent mechanism

AIM To evaluate the effects of the non-selective, non-steroidal anti-infammatory drug （NSAID） acetylsalicylic acid （ASA）, on ex vivo embryonic kidney growth and development.METHODS Pairs of fetal mouse kidneys at embryonic day 12.5 were cultured ex vivo in increasing concentrations of ASA （0.04-0.4 mg/mL） for up to 7 d. One organ from each pair was grown in control media and was used as the internal control for the experimental contralateral organ. In some experiments, organs were treated with ASA for 48 h and then transferred either to control media alone or control media containing 10 μmol/L prostaglandin E2 （PGE2） for a further 5 d. Fetal kidneys were additionally obtained from prostaglandin synthase 2 homozygous null or heterozygous （PTGS2-/- and PTGS2-/＋） embryos and grown in culture. Kidney cross-sectional area was used to determine treatment effects on kidney growth. Whole-mount labelling to fluorescently detect laminin enabled crude determination of epithelial branching using confocal microscopy.RESULTSIncreasing ASA concentration （0.1, 0.2 and 0.4 mg/mL） significantly inhibited metanephric growth （P 〈 0.05）. After 7 d of culture, exposure to 0.2 mg/mL and 0.4 mg/mL reduced organ size to 53% and 23% of control organ size respectively （ P 〈 0.01）. Addition of 10 μmol/L PGE2 to culture media after exposure to 0.2 mg/mL ASA for 48 h resulted in a return of growth area to control levels. Application of control media alone after cessation of ASA exposure showed no benefit on kidney growth. Despite the apparent recovery of growth area with 10 μmol/L PGE2, no obvious renal tubular structures were formed. The number of epithelial tips generated after 48 h exposure to ASA was reduced by 40% （0.2 mg/mL; P 〈 0.05） and 47% （0.4 mg/mL; P 〈 0.01）. Finally, growth of PTGS2-/- and PTGS2＋/- kidneys in organ culture showed no differences, indicating that PTGS2 derived PGE2 may at best have a minor role.CONCLUSIONASA reduces early renal growth and development but the role of prostaglandins in this may be minor.

Protective effects of prostaglandin E1 on hepatocytes

INTRODUCTION E Numerous studies have demonstrated the protective action of prostaglandin E1(PGE1) on experimental animal models of liver injury and on patients with

Short-chain fatty acids act as antiinflammatory mediators by regulating prostaglandin E_2 and cytokines

AIM： To investigate the effect of short-chain fatty acids （SCFAs） on production of prostaglandin E2 （PGE2）, cytokines and chemokines in human monocytes. METHODS： Human neutrophils and monocytes were isolated from human whole blood by using 1-Step Polymorph and RosetteSep Human Monocyte Enrichment Cocktail, respectively. Human GPR41 and GPR43 mRNA expression was examined by quantitative realtime polymerase chain reaction, The calcium flux assay was used to examine the biological activities of SCFAs in human neutrophils and monocytes. The effect of SCFAs on human monocytes and peripheral blood mononuclear cells （PBMC） was studied by measuring PGE2, cytokines and chemokines in the supernatant. The effect of SCFAs in vivo was examined by intraplantar injection into rat paws. RESULTS： Human GPR43 is highly expressed in human neutrophils and monocytes. SCFAs induce robust calcium flux in human neutrophils, but not in human monocytes. In this study, we show that SCFAs can induce human monocyte release of PGE2 and that this effect can be enhanced in the presence of lipopolysaccharide （LPS）. In addition, we demonstrate that PGE2 production induced by SCFA was inhibited by pertussis toxin, suggesting the involvement of a receptor-mediated mechanism. Furthermore, SCFAs can specifically inhibit constitutive monocyte chemotactic protein-1 （MCP-1） production and LPS-induced interleukin-10 （IL-10） production in human monocytes without affecting the secretion of other cytokines and chemokines examined. Similar activities were observed in human PBMC for the release of PGE2, MCP-1 and IL-10 after 5CFA treatment. In addition, SCFAs inhibit LPS-induced production of tumor necrosis factor-α and interferon-7 in human PBIVlC. Finally, we show that SCFAs and LPS can induce PGE2 production in vivo by intraplantar injection into rat paws （P 〈 0.01）. CONCLUSION： SCFAs can have distinct antiinflammatory activities due to their regulation of PGE2, cytokine and chemokine release from human immune cells.

Measurement of prostaglandin metabolites is useful in diagnosis of small bowel ulcerations

BACKGROUND We recently reported on a hereditary enteropathy associated with a gene encoding a prostaglandin transporter and referred to as chronic enteropathy associated with SLCO2 A1 gene(CEAS). Crohn's disease(CD) is a major differential diagnosis of CEAS, because these diseases share some clinical features. Therefore, there is a need to develop a convenient screening test to distinguish CEAS from CD.AIM To examine whether prostaglandin E major urinary metabolites(PGE-MUM) can serve as a biomarker to distinguish CEAS from CD.METHODS This was a transactional study of 20 patients with CEAS and 98 patients with CD.CEAS was diagnosed by the confirmation of homozygous or compound heterozygous mutation of SLCO2 A1. We measured the concentration of PGEMUM in spot urine by radioimmunoassay, and the concentration was compared between the two groups of patients. We also determined the optimal cut-off value of PGE-MUM to distinguish CEAS from CD by receiver operating characteristic(ROC) curve analysis.RESULTS Twenty Japanese patients with CEAS and 98 patients with CD were enrolled.PGE-MUM concentration in patients with CEAS was significantly higher than that in patients with CD(median 102.7 vs 27.9 μg/g × Cre, P < 0.0001). One log unit increase in PGE-MUM contributed to 7.3 increase in the likelihood for the diagnosis of CEAS [95% confidence interval(CI) 3.2-16.7]. A logistic regression analysis revealed that the association was significant even after adjusting confounding factors(adjusted odds ratio 29.6, 95%CI 4.7-185.7). ROC curve analysis revealed the optimal PGE-MUM cut-off value for the distinction of CEAS from CD to be 48.9 μg/g × Cre with 95.0% sensitivity and 79.6% specificity.CONCLUSION PGE-MUM measurement is a convenient, non-invasive and useful test for the distinction of CEAS from CD.

Thymoquinone suppresses migration of Lo Vo human colon cancer cells by reducing prostaglandin E2 induced COX-2 activation

AIM To identify potential anti-cancer constituents in natural extracts that inhibit cancer cell growth and migration. METHODS Our experiments used high dose thymoquinone (TQ) as an inhibitor to arrest LoVo (a human colon adenocarcinoma cell line) cancer cell growth, which was detected by cell proliferation assay and immunoblotting assay. Low dose TQ did not significantly reduce LoVo cancer cell growth. Cyclooxygenase 2 (COX-2) is an enzyme that is involved in the conversion of arachidonic acid into prostaglandin E2 (PGE2) in humans. PGE2 can promote COX-2 protein expression and tumor cell proliferation and was used as a control. RESULTS Our results showed that 20 mu mol/L TQ significantly reduced human LoVo colon cancer cell proliferation. TQ treatment reduced the levels of p-PI3K, p-Akt, p-GSK3 beta, and beta-catenin and thereby inhibited the downstream COX-2 expression. Results also showed that the reduction in COX-2 expression resulted in a reduction in PGE2 levels and the suppression of EP2 and EP4 activation. Further analysis showed that TG treatment inhibited the nuclear translocation of beta-catenin in LoVo cancer cells. The levels of the cofactors LEF-1 and TCF-4 were also decreased in the nucleus following TQ treatment in a dose-dependent manner. Treatment with low dose TQ inhibited the COX-2 expression at the transcriptional level and the regulation of COX-2 expression efficiently reduced LoVo cell migration. The results were further verified in vivo by confirming the effects of TQ and/or PGE2 using tumor xenografts in nude mice. CONCLUSION TQ inhibits LoVo cancer cell growth and migration, and this result highlights the therapeutic advantage of using TQ in combination therapy against colorectal cancer.

Haplotype of prostaglandin synthase 2/cyclooxygenase 2 is involved in the susceptibility to inflammatory bowel disease

AIM： Prostaglandin G/H synthase 2 （PTGS2 or COX2） is one of the key factors in the cellular response to inflammation. PTGS2 is expressed in the affected intestinal segments of patients with inflammatory bowel diseases （IBD）. In IBD patients, non-steroidal anti-inflammatory drugs, which have been shown to reduce both the production and activity of PTGS2, may activate IBD and aggravate the symptoms. We aimed at examining genetic variants of PTGS2 that may be risk factors for IBD. METHODS： We genotyped 291 individuals diagnosed with IBD and 367 controls from the Dutch population for the five most frequent polymorphisms of the PTG52 gene. Clinical data were collected on all patients. DNA was extracted via normal laboratory methods. Genotyping was carried out using multiplex PCR followed by the Invader Assay and the 5＇ exonuclease assay （TaqMan）. New polymorphism screening was performed by pre-screening with denaturing high-performance liquid chromatography, followed by fluorescent sequencing. RESULTS： Allele 5209G was weakly associated with Crohn＇s disease （odds ratio [OR] 1.63, 95% confidence interval [CI] 1.03-2.57）, and allele 8473T with ulcerativecolitis （OR 1.50, 95%CI 1.00-2.27）. The haplotype including both alleles showed a strong association with IBD （OR 13.15, 95%CI 3.17-116.15）. This haplotype, while rare （-0.3%） in the general population, is found more frequently in patients （3.5%）. CONCLUSION： Our data suggest that this haplotype of PTGS2 contributes to the susceptibility of IBD.

Elevated serum prostaglandin E2 predicts the risk of infection in hepatitis B virus-related acute-on-chronic liver failure patients

Objective: To evaluate the serum Prostaglandin E2(PGE2) level in Acute-on-chronic liver failure(ACLF) and determine its predicative value for infection.Methods: From April 2014 to April 2015, ninety-one patients with hepatitis B virus and ACLF but without infection were enrolled into this prospective study that was carried out at our Hospital. Twenty patients with stable chronic hepatitis B were enrolled from the outpatient department and twenty healthy control subjects without any disease were enrolled from hospital staff. Serum PGE2 levels were determined using ELISA at enrollment. Clinical and laboratory parameters were collected. Receiver operating characteristic(ROC) curves were used to determine optimal cut-off values to predict infection.Results: Significantly higher PGE2 levels were found in patients with ACLF in comparison with healthy controls and patients with stable CHB(P < 0.000 1). In ACLF patients, PGE2 levels were significantly higher in patients that eventually developed infection than those without this complication(P < 0.000 1). ROC analysis showed that serum PGE2(area under the ROC curve, 0.83) could predict infection in patients with ACLF with sensitivity of 78.4% and specificity of 81.5% using a threshold of 141 pg/m L.Conclusions: Serum PGE2 is associated with the susceptibility to secondary infections for patients with ACLF. Increased PGE2 serum levels may serve as a potential biomarker for developing infections in ACLF patients.

Changes of nitric oxide and endothelin, thromboxane A2 and prostaglandin in cirrhotic patients undergoing liver transplantation

AIM： To investigate the perioperative changes of nitric oxide （NO） and endothelin （ET）, thromboxane A2 （TXA2） and prostaglandin （PGI2） during liver transplantation in end-stage liver disease patients. METHODS： Twenty-seven patients with end-stage cirrhosis undergoing liver transplantation were enrolled in this prospective study. Blood samples were obtained from superior vena at five different surgical stages. Plasma concentrations of nitrate and nitrite were determined to reflect plasma NO levels. Plasma levels of ET-1, 6-keto-PGF1 alpha and thromboxane B2 （TXB2）, the latter two being stable metabolites of PGI2 and TXA2 respectively, were measured.RESULTS： The NO level decreased significantly after vascular cross-clamping and increased significantly at 30 rain after reperfusion. While the ET levels at 30 rain after clamping and after reperfusion were significantly elevated. The ratio of NO/ET decreased significantly at 30 rain after vascular cross-clamping and at the end of surgery. The PGI2 level and the TXA2 during liver transplantation were significantly higher than the baseline level, but the ratio of TXA2/PGI2 decreased significantly at 30 rain after clamping. CONCLUSION： NO/ET and TXA2/PGI2 change during liver transplantation. Although the precise mechanism remains unknown, they may play a role in the pathobiology of a variety of liver transplant-relevant processes.

Cyclooxygenase-2 expression is associated with initiation of hepatocellular carcinoma, while prostaglandin receptor-1 expression predicts survival

AIM to determine whether cyclooxygenase-2(COX-2) and prostaglandin E1 receptor(EP1) contribute to disease and whether they help predict prognosis.METHODS We retrospectively reviewed the records of 116 patients with hepatocellular carcinoma(HCC) who underwent surgery between 2008 and 2011 at our hospital. Expression of COX-2 and EP1 receptor was examined by immunohistochemistry of formalin-fixed, paraffinembedded tissues using polyclonal antibodies. Possible associations between immunohistochemical scores and survival were determined.RESULTS Factors associated with poor overall survival(OS) were alpha-fetoprotein > 400 ng/m L, tumor size ≥ 5 cm, and high EP1 receptor expression, but not high COX-2 expression. Disease-free survival was not significantly different between patients with low or high levels of COX-2 or EP1. COX-2 immunoreactivity was significantly higher in well-differentiated HCC tissues(Edmondson grade Ⅰ-Ⅱ) than in poorly differentiated tissues(Edmondson grade Ⅲ-Ⅳ)(P = 0.003). EP1 receptor immunoreactivity was significantly higher in poorly differentiated tissue than in well-differentiated tissue(P = 0.001).CONCLUSION COX-2 expression appears to be linked to early HCC events(initiation), while EP1 receptor expression may participate in tumor progression and predict survival.

Association between the levels of prostaglandin E2 in tears and severity of dry eye

AIM: To investigate the relationship between the levels of prostaglandin E2(PGE2) in tears and dry eye disease severity based on both clinical symptoms and signs.METHODS: Tear samples were collected from 36 non-Sj?gren syndrome dry eye patients(10 males and 26 females, mean age 50.11±11.17 y). All participants completed the Ocular Surface Disease Index(OSDI) questionnaire and underwent a detailed ophthalmic examination including, tear film breakup time(TBUT), ocular surface fluorescein staining, Schirmer I test, and meibomian gland assessment. The level of PGE2 in tears was measured using enzyme-linked immunosorbent assay(ELISA). The independent associations between tear PGE2 levels and other variables including demographics, OSDI scores, TBUT, Schirmer scores, ocular surface staining scores, and stage of meibomian gland dysfunction(MGD) were evaluated using linear regression analysis. RESULTS: The mean PGE2 level in tears of dry eye patients was 537.85±234.02 pg/mL. The tear PGE2 levels significantly positively correlated with OSDI scores(R=0.608, P<0.001), however, they did not significantly associate with TBUT(R=0.153, P=0.373), Schirmer scores(R=-0.098, P=0.570), ocular surface staining scores(R=0.282, P=0.095), and stage of MGD(R=-0.107, P=0.535).Male sex was significantly negatively correlated with tear PGE2 levels.CONCLUSION: The levels of PGE2 in tears are positively correlated with dry eye symptoms. However, no significant association was found between tear PGE2 levels and the results of other common dry eye diagnostic tests.

Gastro-protective action of lafutidine mediated by capsaicin-sensitive afferent neurons without interaction with TRPV1 and involvement of endogenous prostaglandins

AIM： Lafutidine, a histamine H2 receptor antagonist, exhibits gastro-protective action mediated by capsaicinsensitive afferent neurons （CSN）. We compared the effect between lafutidine and capsaicin, with respect to the interaction with endogenous prostaglandins （PG）, nitric oxide （NO） and the afferent neurons, including transient receptor potential vanilloid subtype 1 （TRPV1）. METHODS： Male SD rats and C57BL/6 mice, both wildtype and prostacyclin IP receptor knockout animals, were used after 18 h of fasting. Gastric lesions were induced by the po administration of HCl/ethanol （60% in 150 mmol/L HCl） in a volume of 1 mL for rats or 0.3 mL for mice. RESULTS： Both lafutidine and capsaicin （1-10 mg/kg, po） afforded dose-dependent protection against HCI/ ethanol in rats and mice. The effects were attenuated by both the ablation of CSN and pretreatment with NG-nitro- L-arginine methyl ester, yet only the effect of capsaicin was mitigated by prior administration of capsazepine, the TRPV1 antagonist, as well as indomethacin. Lafutidine protected the stomach against HCl/ethanol in IP receptor knockout mice, similar to wild-type animals, while capsaicin failed to afford protection in the animals lacking IP receptors. Neither of these agents affected the mucosal PGE2 or 6-keto PGF1α contents in rat stomachs. Capsaicin evoked an increase in [Ca^2＋]i in rat TRPV1-transfected HEK293 cells while lafutidine did not. CONCLUSION： These results suggest that although both lafutidine and capsaicin exhibit gastro-protective action mediated by CSN, the mode of their effects differs regarding the dependency on endogenous PGs/IP receptors and TRPV1. It is assumed that lafutidine interacts with CSN at yet unidentified sites other than TRPV1.

Effect of c-fos antisense probe on prostaglandin E_2-induced upregulation of vascular endothelial growth factor mRNA in human liver cancer cells

AIM: To examine the effect of prostaglandin E2 (PGE2) on the expression of vascular endothelial growth factor (VEGF) mRNA in the human hepatocellular carcinoma (HCC) HepG2 cells and the possible involvement of c-fos protein in this process.METHODS: Human HCC HepG2 cells were divided into three groups treated respectively with PGE2, a combination of PGE2 and c-fos antisense oligodeoxynucleotide (ASO),and PGE2 plus c-fos sense oligodeoxynudeotide (SO). The expression of VEGF mRNA in HepG2 cells after different treatments was detected by reverse transcriptase-polymerase chain reaction (RT-PCR). The relative expression level of VEGF mRNA in HepG2 cells in each group was measured.RESULTS: Administration of PGE2 resulted in an increased expression of c-fosand VEGF mRNA in HepG2 cells. The relative expression level of c-fos mRNA reached the peak at 3 h (68.4±4.7%) after PGE2 treatment, which was significantly higher than that at 0 h (20.6±1.7%, P＜0.01).Whereas, the highest expression level of VEGF mRNA was observed at 6 h (100.5±6.1%) after PGE2 treatment, which was significantly higher than that at 0 h (33.2±2.4%,P＜0.01). C-fos ASO significantly reduced PGE2-induced VEGF mRNA expression in HepG2 cells.CONCLUSION: PGE2 increases the expression and secretion of VEGF in HCC cells by activating the transcription factor c-fos, promotes the angiogenesis of HCC and plays an important role in the pathogenesis of liver cancer.

Prostaglandin E_1 in conjunction with high doses of vitamin B_(12) improves nerve conduction velocity of patients with diabetic peripheral neuropathy

BACKGROUND： Prostaglandin El improves diabetic peripheral neuropathy in symptoms and sensory threshold. Vitamin Bi and methyl-vitamin BI2 improve microcirculation to peripheral nerve tissue and promote neurotrophy. OBJECTIVE： To observe motor nerve and sensory nerve conduction velocity in patients with diabetic peripheral neuropathy, prior to and after treatment with prostaglandin El, vitamin B I and different doses of vitamin B 12. DESIGN, TIME AND SETTING： Randomized, controlled experiment, performed at the Department of Neurology, Beijing Hantian Central Hospital, between February 2002 and September 2007. PARTICIPANTS： A total of 122 patients with type 2 diabetic peripheral neuropathy; 73 males and 49 females were included. All patients met the diagnostic criteria of diabetes mellitus, as determined by the World Health Organization in 1999 and 2006, and also the diagnostic criteria of diabetic peripheral neuropathy. For each subject, conduction disorders in the median nerve and in the common peroneal nerve were observed using electromyogram. Also, after diet and drug treatment, the blood glucose level of subjects was observed to be at a satisfactory level for more than two weeks, and the symptoms of diabetic peripheral neuropathy were not alleviated. METHODS： All patients were randomly divided into the following three groups. A control group （n = 40）, in which, 100 mg vitamin B1 and 500 μg vitamin BI2 were intramuscularly injected. A vitamin B12 low-dose treated group （ n = 42）, in which 10 μ g prostaglandin E1 in 250 mL physiological saline was intravenously injected once a day and 100 mg vitamin BI and 500 11 g vitamin BI2 was intramuscularly injected once a day. Lastly, a vitamin B12 high-dose treated group （n = 40）, in which administration was the same as in the vitamin B12 low-dose treated group, except that 500 11 g vitamin BI2 was replaced by 1mg vitamin B12. Administration was performed for four weeks for each group. MAIN OUTCOME MEASURES： The motor nerve and sensory nerve conduction velocity of the median nerve and the common peroneal nerve were determined using an electromyogram electronic stimulator （Neuropack-11, Nihon Kohden, Japan）. RESULTS： The motor nerve and sensory nerve conduction velocities of the median nerve and the common peroneal nerve were significantly faster after treatment compared to before treatment in all 3 groups （P 〈 0.05q）.01）. Compared with the control group, the motor nerve and sensory nerve conduction velocities were significantly faster in the vitamin B12 low-dose treated group and in the vitamin B12 high-dose treated group （P 〈 0.01）. The motor nerve and sensory nerve conduction velocities were significantly faster in the vitamin B12 high-dose treated group compared to the vitamin B12 low-dose treated group （P 〈 0.05）. CONCLUSION： Prostaglandin E1, in conjunction with vitamin B12, can improve neural functional states and speed up peripheral motor nerve and sensory nerve conduction velocity in diabetic peripheral neuropathy. In addition, better effects are achieved using prostaglandin E1 in conjunction with high doses of vitamin B 12.

Effects of Prostaglandins and Leukotrienes on Hypoxic Pulmonary Vasoconstriction in Rats

To investigate the effects of prostaglandins (PGs) and leukotrienes (LTs) on hypoxic pulmonary vasoconstriction (HPV), in vivo rats experiment and in vitro perfused lung experiment were conducted. The effect of hypoxia on hemodynamics, concentrations of TXB 2 and 6 keto PGF 1α in serum and lung tissue during hypoxia and effects of PGs and LTs on HPV were observed. The results showed that pulmonary arterial pressure (P pa ) and pulmonary vascular resistance were increased during hypoxia, but cardiac output and systemic arterial pressure were decreased. There were increases of the concentrations of TXB 2 and 6 keto PGF 1α and their ratio in serum and lung tissue during hypoxia. After use of cyclooxygenase inhibitor (indomethacin) in vivo and in vitro , HPV was augmented respectively, but after use of lipoxygenase inhibitor (diethylcorbamazine) or leukotriene receptor blocker (LY 171883), HPV was attenuated. It was suggested that LTs mediated pulmonary vasoconstriction, PGs inhibited pulmonary vasoconstriction and they played a modulating role during hypoxia.