Celecoxib reduces hepatic vascular resistance in portal hypertension by amelioration of endothelial oxidative stress.

The balance between endothelial nitric oxide (NO) synthase (eNOS) activation and production of reactive oxygen species (ROS) is very important for NO homeostasis in liver sinusoidal endothelial cells (LSECs). Overexpression of cyclooxygenase-2 (COX-2), a major intravascular source of ROS production, has been observed in LSECs of cirrhotic liver. However, the links between low NO bioavailability and COX-2 overexpression in LSECs are unknown. This study has confirmed the link between low NO bioavailability and COX-2 overexpression by COX-2-dependent PGE2-EP2-ERK1/2-NOX1/NOX4 signalling pathway in LSECs in vivo and in vitro. In addition, the regulation of COX-2-independent LKB1-AMPK-NRF2-HO-1 signalling pathway on NO homeostasis in LSECs was also elucidated. The combinative effects of celecoxib on diminishment of ROS via COX-2-dependent and COX-2-independent signalling pathways greatly decreased NO scavenging. As a result, LSECs capillarisation was reduced, and endothelial dysfunction was corrected. Furthermore, portal hypertension of cirrhotic liver was ameliorated with substantial decreasing hepatic vascular resistance and great increase of portal blood flow. With the advance understanding of the mechanisms of LSECs protection, celecoxib may serve as a potential therapeutic candidate for patients with cirrhotic portal hypertension.

Smad4 deficiency substitutes Cdkn2b but not Cdkn2a downregulation in pancreatic cancer following induction of genetic events in adult mice.

BACKGROUND: Minor progress in pancreatic cancer treatment and prognosis implies that more reliable animal models are urgently needed to decipher its molecular mechanisms and preclinical research. We recently reported a genetically engineered adult mouse model where Cdkn2b downregulation was required together with Cdkn2a downregulation to inactivate the Rb pathway. Besides, the role of Smad4, which is mutated more frequently than Cdkn2b in human pancreatic cancer, was determined critical on the development of the pancreas tumor by some reports. However, the impact of Smad4 deficiency in combination with PDAC-relevant mutations, such as Cdkn2a when induced in adult pancreas has not been completely elucidated in mice. METHODS: Lentiviral delivered oncogene/tumor suppressors in adult pancreas. The development of pancreatic cancer was monitored. Hematoxylin and eosin staining and immunofluorescence were performed for pathological identification of the pancreatic cancer. Real-time polymerase chain reaction, immunofluorescence and western blot were used to test gene expression. RESULTS: Loss of Smad4 could cooperate with alterations of KRAS, Trp53, and Cdkn2a to induce pancreatic cancer in adult mice. The role of Smad4 was mainly in downregulating the expression of Cdkn2b and further inducing phosphorylation of the Rb1 protein. CONCLUSIONS: These findings show an essential role of Smad4 deficiency in pancreatic ductal adenocarcinoma (PDAC) formation. This model better recapitulates the adult onset, clonal origin, and genetic alterations in human PDAC and can be simply generated on a large-scale.

Prevention of Severe Acute Pancreatitis With Cyclooxygenase-2 Inhibitors: A Randomized Controlled Clinical Trial.

OBJECTIVES: Severe acute pancreatitis (SAP) is still a big challenge. Accumulated data showed that overexpression of cyclooxygenase-2 (COX-2) in acute pancreatitis and experimental pancreatitis could be attenuated with COX-2 inhibitors. This study was aimed to evaluate whether the occurrence of SAP could be prevented by selective COX-2 inhibitors. METHODS: A total of 190 patients with predicted SAP were randomized into convention group or convention plus COX-2 inhibitors (C+COX-2-Is) group. Besides conventional treatment to all patients in 2 groups, parecoxib (40 mg/d intravenous injection for 3 days) and celecoxib (200 mg oral or tube feeding twice daily for 7 days) were sequentially administrated to the patients in the C+COX-2-Is group. The primary outcome was predefined as the occurrence of SAP. The serum levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) for all of the patients were measured. RESULTS: The occurrence of SAP in the C+COX-2-Is group was decreased 47.08% compared with the convention group, 21.05% (20/95) vs 39.78% (37/93), P = 0.005. A reduction of late local complications was also shown in the C+COX-2-Is group, 18.95% (18/93) vs 34.41% (32/95), P = 0.016. The serum levels of IL-6 and TNF-α were significantly lower in the C+COX-2-Is group than those in the convention group, P < 0.05. Parecoxib relieved abdominal pain more rapidly and decreased the consumption of meperidine. An incremental reduction of cost for 1% decrease of SAP occurrence was RMB475. DISCUSSION: Sequential administration of parecoxib and celecoxib in patients with predicted SAP obtained about half-reduction of SAP occurrence through decreasing serum levels of TNF-α and IL-6. This regimen presented good cost-effectiveness.

A method for rapid determination of arsenic species in vegetables using microwave-assisted extraction followed by detection with HPLC hyphenated to inductively coupled plasma-mass spectrometry.

Driven by the significant need for characterization of the chemical speciation of arsenic in food, this work developed a method for rapid determination of four common arsenic species, namely, arsenite, arsenate, monomethyl arsenic acid, and dimethyl arsenic acid, in vegetables using microwave-assisted extraction, followed by detection with high-performance liquid chromatography hyphenated to inductively coupled plasma-mass spectrometry. Initial screening results showed that microwave-assisted extraction using 1% HNO3 exhibited the highest overall efficiencies for all arsenic species without causing significant degradation of the organic ones. With the aid of response surface methodology, the optimum conditions established for extraction of arsenic species from vegetables were: 500 mg of freeze-dried vegetable sample, extracted by closed vessel microwave-assisted extraction using 10 mL of 2% v/v HNO3 at 90°C for 17 min. Application of the method in the analysis of 24 market vegetable samples indicates that the extraction efficiencies for total arsenic species were in the range of 91.4-106%. Arsenite and arsenate were found to be the predominant arsenic species in the vegetables, which suggests that vegetable consumption could be an important route of inorganic arsenic exposure for the population with a heavy vegetable diet in arsenic polluted regions.

Celecoxib ameliorates liver cirrhosis via reducing inflammation and oxidative stress along spleen-liver axis in rats.

BACKGROUND & AIMS: Splenomegaly is usually taken as a consequence of liver cirrhosis. However, as a risk factor for cirrhosis, the impacts of spleen-liver axis on the development of cirrhosis are largely unknown. This study focused on the impacts of splenomegaly on the development of cirrhosis and assessment of the effects of celecoxib, a selective COX-2 inhibitor, on the splenomegaly and cirrhotic liver. MATERIALS AND METHODS: Liver cirrhosis was induced by thioacetamide (TAA). Sixty rats were randomly divided into control, TAA-16w, TAA + celecoxib groups and normal, TAA + sham, TAA + splenectomy groups. Hepatic stellate cells (HSCs) or hepatocytes were co-cultured with splenocytes from those groups. RESULTS: Splenocytes of cirrhotic rats stimulated the HSCs activation and induced hepatocyte apoptosis via enhancing oxidative stress. The hepatic levels of NOX-4 and the in situ O2- were profoundly reduced in TAA + splenectomy group by 50.6% and 18.5% respectively, p < 0.05. Celecoxib significantly decreased the hepatic fibrotic septa induced with TAA by 50.8%, p < 0.05. Splenic lymphoid tissue proliferation and proinflammatory cytokines of the cirrhotic rats were also obviously suppressed by celecoxib, p < 0.05. Compared with the HSC or hepatocyte cell line co-cultured with the cirrhotic splenocytes, the expression of alpha-SMA, NOX-4, in situ O2- or the levels of cleaved caspase3 and NOX-4 were significantly decreased in those cell lines co-cultured with cirrhotic splenocytes treated by celecoxib, p < 0.05. CONCLUSION: Splenomegaly contributed to the development of liver cirrhosis through enhancing oxidative stress in liver. Celecoxib could effectively ameliorate liver cirrhosis via reducing inflammatory cytokines and immune cells derived from spleen and suppressing oxidative stress.

A novel pancreatic cancer model originated from transformation of acinar cells in adult tree shrew, a primate-like animal.

Pancreatic cancer is one of the most lethal common cancers. The cell of origin of pancreatic ductal adenocarcinoma (PDAC) has been controversial, and recent evidence suggested acinar cells as the most probable candidate. However, the genetic alterations driving the transformation of pancreatic acinar cells in fully mature animals remain to be deciphered. In this study, lentivirus was used as a tool to introduce genetic engineering in tree shrew pancreatic acinar cells to explore the driver mutation essential for malignant transformation, establishing a novel tree shrew PDAC model, because we found that lentivirus could selectively infect acinar cells in tree shrew pancreas. Combination of oncogenic KRASG12D expression and inactivation of tumor suppressor genes Tp53, Cdkn2a and Cdkn2b could induce pancreatic cancer with full penetrance. Silencing of Cdkn2b is indispensable for Rb1 phosphorylation and tumor induction. Tree shrew PDAC possesses the main histological and molecular features of human PDAC. The gene expression profile of tree shrew PDAC was more similar to human disease than a mouse model. In conclusion, we established a novel pancreatic cancer model in tree shrew and identified driver mutations indispensable for PDAC induction from acinar cells in mature adults, demonstrating the essential roles of Cdkn2b in the induction of PDAC originating from adult acinar cells. Tree shrew could thus provide a better choice than mouse for a PDAC model derived from acinar cells in fully mature animals.