Characterization of the prostaglandin E2 pathway in a rat model of esophageal adenocarcinoma

Accumulating evidence indicates that the cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE2) pathway plays a key role in esophageal carcinogenesis. A better understanding of the pathway downstream of COX-2 may reveal novel targets for the prevention of esophageal adenocarcinoma (EAC). The objective of this study was to characterize the profile of genes involved in PGE2 metabolism and signaling in an experimental model of EAC. Esophagojejunostomy with gastric preservation was performed in wistar rats to induce gastroduodenal reflux. Rats were sacrificed 2 or 4 months after surgery. Nine non-operated rats were used to obtain normal (control) esophageal tissues.

RESULTS

All rats that underwent esophagojejunostomy developed inflammation. In addition, 90% of the animals showed intestinal metaplasia; of those, 40% progressed to AC. This process was accompanied by a significant increase in esophageal PGE2 levels and the induction of both mRNA and protein levels of COX-2, COX-1, prostaglandin E synthase, 15-hydroxyprostaglandin dehydrogenase, and PGE2 receptors EP3, EP4 and especially EP2, which rose to particularly high levels in experimental rats. In addition, exposure to a selective COX-2 inhibitor (SC58125) or an EP1/EP2 antagonist (AH6809), but not an EP4 antagonist (AH23848B), significantly reduced cell proliferation of esophageal explants in 24 hour-organ culture experiments. Our data suggest that, in addition to COX-2, other components of the PGE2 pathway, including COX-1, may play important roles in the development of EAC induced by gastroduodenal reflux in the rat. Although it must be confirmed in vivo, the EP2 receptor may represent a promising selective target in the prevention of Barrett's associated AC.

Cardiac hemodynamic profiles and pro-B-type natriuretic Peptide in cirrhotic patients undergoing liver transplantation

BACKGROUND

The aim of our study was to determine concentrations of amino-terminal pro-B-type natriuretic peptide (NT-proBNP) in patients with cirrhosis, thereby describing the hemodynamic and cardiac profiles to verify the existence of cirrhotic cardiomyopathy.

METHODS

Clinical data, NT-proBNP levels, echocardiography, and right heart hemodynamic measurements were performed on all patients undergoing liver transplantation for cirrhosis.

RESULTS

Our patients showed a hyperdynamic circulation with elevated left-sided pressures despite high cardiac outputs. This observation suggested abnormalities in left ventricular diastolic compliance. We verified these results, because our cohort showed a significant left ventricular mass index and, consequently, diastolic dysfunction. Mean NT-proBNP levels were high. The great expansion of central volume may explain these results and the later development of left ventricular hypertrophy.

CONCLUSION

We concluded that elevated concentrations of NT-proBNP indicated the presence of hyperdynamic syndrome and cardiac dysfunction.