Wenjuan Yang

Celecoxib Ameliorates Portal Hypertension of the Cirrhotic Rats through the Dual Inhibitory Effects on the Intrahepatic Fibrosis and Angiogenesis

Background Increased intra-hepatic resistance to portal blood flow is the primary factor leading to portal hypertension in cirrhosis. Up-regulated expression of cyclooxygenase-2 (COX-2) in the cirrhotic liver might be a potential target to ameliorate portal hypertension. Objective To verify the effect of celecoxib, a selective inhibitor of COX-2, on portal hypertension and the mechanisms behind it. Methods Cirrhotic liver model of rat was established by peritoneal injection of thiacetamide (TAA). 36 rats were randomly assigned to control, TAA and TAA+celecoxib groups. Portal pressures were measured by introduction of catheters into portal vein. Hepatic fibrosis was assessed by the visible hepatic fibrotic areas and mRNAs for collagen III and α-SMA. The neovasculature was determined by hepatic vascular areas, vascular casts and CD31 expression. Expressions of COX-2, vascular endothelial growth factor (VEGF), VEGF receptor-2 (VEGFR-2) and related signal molecules were quantitated. Results Compared with TAA group, the portal pressure in TAA+celecoxib group was significantly decreased by 17.8%, p<0.01. Celecoxib treatment greatly reduced the tortuous hepatic portal venules. The data of fibrotic areas, CD31expression, mRNA levels of α-SMA and collagen III in TAA+celecoxib group were much lower than those in TAA group, p<0.01. Furthermore, the up-regulation of hepatic mRNA and protein levels of VEGF, VEGFR-2 and COX-2 induced by TAA was significantly inhibited after celecoxib treatment. The expressions of prostaglandin E2 (PGE2), phosphorylated extracellular signal-regulated kinase (p-ERK), hypoxia-inducible factor-1α (HIF-1α), and c-fos were also down-regulated after celecoxib treatment. Conclusions Long term administration of celecoxib can efficiently ameliorate portal hypertension in TAA rat model by its dual inhibitory effects on the intrahepatic fibrosis and angiogenesis. The anti-angiogenesis effect afforded by celecoxib may attribute to its modulation on VEGF/VEGFR-2 through the down-regulation of integrated signal pathways involving PGE2- HIF-1α- VEGF and p-ERK- c-fos- VEGFR-2.

Celecoxib attenuates hepatic cirrhosis through inhibition of epithelial-to-mesenchymal transition of hepatocytes

The epithelial–mesenchymal transition (EMT) of hepatocytes is a key step for hepatic fibrosis and cirrhosis. Long‐term administration of celecoxib, a selective cyclooxygenase‐2 (COX‐2) inhibitor, can ameliorate hepatic fibrosis. This research aimed to examine the effect of celecoxib on the EMT of hepatocytes during the development of liver cirrhosis.

Chemoprevention of cancers in gastrointestinal tract with cyclooxygenase 2 inhibitors.

The finding that cyclooxygenase-2 (COX-2) is over-expressed and plays an important role in carcinogenesis in gastrointestinal (GI) cancers including esophagus, gastric and colorectal cancers has triggered the researches of COX-2 inhibitors as the chemopreventive option for GI cancers. This reviewer updates the current molecular biology on the regulation of COX-2 expression, pharmacological concepts of COX-2 inhibitors in the chemoprevention of GI tract, the clinical efficacies of COX -2 inhibitors in prevention of cancers in GI tract and associated main adverse events. In inflammation, COX-2 expression is regulated both at the transcriptional and posttranscriptional levels. Hypermethylation of the CpG island in the COX-2 gene is the major cause of COX-2 silencing in a subset of GI cancers. However, the tumor-inhibitory efficacy of non-selective non-steroidal antiinflammatory drugs (NSAIDs) or selective COX-2 inhibitors is not necessarily related to their COX-inhibitory potential. These compounds harbor additional pharmacological activities that are entirely independent of its COX-2 inhibitory activity. The clearly identified targets relevant for anticancer therapy, the benefits from clinical chemoprevention of GI tract cancers and the absence of adverse findings of cardiovascular function or histopathology in preclinical toxicology studies indicate the promising results of COX-2 inhibitors. The efficacy and toxicity of NSAIDs are a consequence of the inhibition of the COX enzymes. Therefore, an optimal regime of COX-2 inhibitors in chemoprevention of GI cancers should be further investigated probably by adjustment of dosage, duration, integration of co-therapy and careful selection of candidates.

Immunomodulatory therapies for acute pancreatitis.

It is currently difficult for conventional treatments of acute pancreatitis (AP), which primarily consist of anti-inflammatory therapies, to prevent the progression of AP or to improve its outcome. This may be because the occurrence and progression of AP, which involves various inflammatory cells and cytokines, includes a series of complex immune events. Considering the complex immune system alterations during the course of AP, it is necessary to monitor the indicators related to immune cells and inflammatory mediators and to develop more individualized interventions for AP patients using immunomodulatory therapy. This review discusses the recent advances in immunomodulatory therapies. It has been suggested that overactive inflammatory responses should be inhibited and excessive immunosuppression should be avoided in the early stages of AP. The optimal duration of anti-inflammatory therapy may be shorter than previously expected (< 24 h), and appropriate immunostimulatory therapies should be administered during the period from the 3(rd) d to the 14(th) d in the course of AP. A combination therapy of anti-inflammatory and immune-stimulating drugs would hopefully constitute an alternative to anti-inflammatory drug monotherapy. Additionally, the detection of the genotypes of critical inflammatory mediators may be useful for screening populations of AP patients at high risk of severe infections to enable the administration of early interventions to improve their prognosis.

Quantitative Evaluation and Selection of Reference Genes for Quantitative RT-PCR in Mouse Acute Pancreatitis

The analysis of differences in gene expression is dependent on normalization using reference genes. However, the expression of many of these reference genes, as evaluated by quantitative RT-PCR, is upregulated in acute pancreatitis, so they cannot be used as the standard for gene expression in this condition. For this reason, we sought to identify a stable reference gene, or a suitable combination, for expression analysis in acute pancreatitis. The expression stability of 10 reference genes (ACTB, GAPDH, 18sRNA, TUBB, B2M, HPRT1, UBC, YWHAZ, EF-1α, and RPL-13A) was analyzed using geNorm, NormFinder, and BestKeeper software and evaluated according to variations in the raw Ct values. These reference genes were evaluated using a comprehensive method, which ranked the expression stability of these genes as follows (from most stable to least stable): RPL-13A, YWHAZ > HPRT1 > GAPDH > UBC > EF-1α > 18sRNA > B2M > TUBB > ACTB. RPL-13A was the most suitable reference gene, and the combination of RPL-13A and YWHAZ was the most stable group of reference genes in our experiments. The expression levels of ACTB, TUBB, and B2M were found to be significantly upregulated during acute pancreatitis, whereas the expression level of 18sRNA was downregulated. Thus, we recommend the use of RPL-13A or a combination of RPL-13A and YWHAZ for normalization in qRT-PCR analyses of gene expression in mouse models of acute pancreatitis.

Betaine attenuates chronic alcohol‑induced fatty liver by broadly regulating hepatic lipid metabolism

Betaine has previously been demonstrated to protect the liver against alcohol-induced fat accumulation. However, the mechanism through which betaine affects alcohol-induced hepatic lipid metabolic disorders has not been extensively studied. The present study aimed to investigate the effect of betaine on alcoholic simple fatty liver and hepatic lipid metabolism disorders. A total of 36 rats were randomly divided into control, ethanol and ethanol + betaine groups. Liver function, morphological alterations, lipid content and tumor necrosis factor (TNF)-α levels were determined. Hepatic expression levels of diacylglycerol acyltransferase (DGAT) 1, DGAT2, sterol regulatory element binding protein (SREBP)-1c, SREBP-2, fatty acid synthase (FAS), 3-hydroxy-3-methyl-glutaryl (HMG)-CoA reductase, peroxisome proliferator-activated receptor λ coactivator (PGC)-1α, adiponectin receptor (AdipoR) 1 and AdipoR2 were quantified. Serum and adipose tissue adiponectin levels were assessed using an enzyme-linked immunoassay. The results demonstrated that alcohol-induced ultramicrostructural alterations in hepatocytes, including the presence of lipid droplets and swollen mitochondria, were attenuated by betaine. Hepatic triglyceride, free fatty acid, total cholesterol and cholesterol ester contents and the expression of DGAT1, DGAT2, SREBP-1c, SREBP-2, FAS and HMG-CoA reductase were increased following ethanol consumption, however were maintained at control levels following betaine supplementation. Alcohol-induced decreases in hepatic PGC-1α mRNA levels and serum and adipose tissue adiponectin concentrations were prevented by betaine. The downregulation of hepatic AdipoR1 which resulted from alcohol exposure was partially attenuated by betaine. No significant differences in liver function, TNF-α, phospholipid and AdipoR2 levels were observed among the control, ethanol and ethanol + betaine groups. Overall, these results indicated that betaine attenuated the alcoholic simple fatty liver by improving hepatic lipid metabolism via suppression of DGAT1, DGAT2, SREBP-1c, FAS, SREBP-2 and HMG-CoA reductase and upregulation of PGC-1α.

Betaine Attenuates Alcohol-Induced Pancreatic Steatosis.

Objectives To explore the effect of betaine on alcoholic pancreatic steatosis and its mechanism. Methods Rats were randomly assigned to control, ethanol, or ethanol + betaine groups. Changes in pancreatic morphology; serum lipid levels; and pancreatic lipid, amylase and lipase levels were determined. The serum and adipose tissue adiponectin level was measured by an enzyme-linked immunoassay. Adiponectin receptor-1 (AdipoR1), AdipoR2, sterol regulatory element binding protein-1c (SREBP-1c), SREBP-2, and fatty acid synthetase expression levels were quantified. The SREBP-1c expression in SW1990 cells treated with various concentrations of ethanol or ethanol plus betaine and/or adiponectin was assessed. Results Alcohol-induced changes in pancreatic morphology were attenuated by betaine. Pancreatic triglyceride, free fatty acid and expression levels of SREBP-1c and fatty acid synthetase were elevated after ethanol feeding but remained at control levels after betaine supplementation. Alcohol-induced decreases in serum and adipose tissue adiponectin, pancreatic AdipoR1, amylase, and lipase were attenuated by betaine. Serum triglyceride and free fatty acid levels were elevated after alcohol consumption and remained higher after betaine supplementation compared with controls. Betaine and/or adiponectin suppressed alcohol-induced SREBP-1c upregulation in vitro. Conclusions Betaine attenuated alcoholic-induced pancreatic steatosis most likely by suppressing pancreatic SREBP-1c both directly and through the restoration of adiponectin signaling.

Corrigendum to “Quantitative Evaluation and Selection of Reference Genes for Quantitative RT-PCR in Mouse Acute Pancreatitis”

[This corrects the article DOI: 10.1155/2016/8367063.].

Su1893 Betaine Alleviates Alcohol-Induced Pancreatic Steatosis in Rats

infiltration, and interstitial edema were all reduced in cerulein-treated PKD3Δpanc mice compared to controls. Conclusion: PKD3Δpanc mice displayed significant attenuation in inflammation, acinar cell necrosis, and severity of pancreatitis. These novel findings indicate that this animal model can be used to demonstrate the role of PKD in the pathobiologic responses in the pancreatic acinar cell during pancreatitis.

Su1679 Attenuation of Hepatic Fibrogenesis and Portal Hypertension in the Cirrhotic Rats With Octreotide

Repair from hepatic injury involves re-activation of morphogenetic signaling pathways. Notch signaling controls cell differentiation and deregulation of the Notch pathway induces several types of diseases including these associated with pericyte. We hypothesized that Notch signaling regulates hepatic stellate cell (HSC, liver pericyte) transdifferentiation through cross-talk with other characterized signaling pathways that regulate HSCs activation, like the Hedgehog (Hh) pathway. We examined Notch signaling in two types of hepatic injury (bile duct ligation, and high fat diet with carbon tetrachloride-induced fibrosis). Immature ductular cells and primary HSCs were manipulated with the γ-secretase inhibitor DAPT to assess the role of Notch signaling in hepatic cell differentiation. To determine the effect of Hh signaling on Notch pathway, cells were treated with the Smoothened inhibitor GDC0449. Finally, Hh signaling was conditionally disrupted inmyofibroblasts in vivo to determine its effects on Notch signaling. Notch-2, Jagged-1 and various Notch target genes were induced in fibrotic liver injury at both mRNA and protein level. HSCs up-regulate both Notch receptor and ligand during culture-activation; DAPT inhibits Notch signaling, preventing activation, promoting quiescence and down-regulating Hh signaling. Similarly, Hh inhibition reduced Notch signaling both in vitro and in vivo. Conclusion: Notch and Hh signaling interact to controls HSC transdifferentiation during injury-induced activation.