Inhibition of the placental growth factor decreases burden of cholangiocarcinoma and hepatocellular carcinoma in a transgenic mouse model.

OBJECTIVES: Hepatocellular carcinoma and cholangiocarcinoma form the majority of primary hepatic tumours and are the third most common cause of cancer-related deaths. These liver tumours rapidly outgrow their vascular supply and become hypoxic, resulting in the production of hypoxia inducible factors and triggering the angiogenic switch. Therefore, inhibiting angiogenesis has proven to be a valuable therapeutic strategy in hepatocellular carcinoma, yet less is known about its use in cholangiocarcinoma. In this study, we assess whether inhibiting the placental growth factor (PlGF) could offer a therapeutic option in mice with hepatocellular carcinoma and cholangiocarcinoma. PlGF is a homologue of the vascular endothelial growth factor, which is only involved in pathological angiogenesis, therefore, its inhibition does not induce adverse effects. METHODS: We have used a chemically induced transgenic mouse model in which both hepatocellular carcinoma and cholangiocarcinoma develop after 25 weeks and are treated with murine monoclonal antibodies targeting PlGF. RESULTS: This study has shown for the first time that inhibiting PlGF decreases the burden of cholangiocarcinoma, by affecting both angiogenesis and inflammation. CONCLUSION: The use of monoclonal antibodies targeting PlGF could thus offer a potential systemic treatment for patients who suffer from primary liver tumours.

Vascular hyporesponsiveness in the mesenteric artery of anaesthetized rats with cirrhosis and portal hypertension: an in-vivo study.

INTRODUCTION: Cirrhosis is complicated by splanchnic vasodilation. Nitric oxide (NO) and prostacyclin contribute to this. Vascular hyporesponsiveness has been reported, but the underlying pathophysiological mechanisms are unclear. OBJECTIVE: This in-vivo study examined the contribution of NO and prostacyclin to the development of vascular hyporesponsiveness in the mesenteric circulation of animals with cirrhosis and portal hypertension. METHODS: Rats underwent common bile duct ligation (CBDL) (n = 11), partial portal vein ligation (PPVL) (n = 12) and sham-operation (sham) (n = 11). Blood flow in the mesenteric artery (MBF) was measured during intramesenteric infusion of endothelium-dependent (acetylcholine) and endothelium-independent vasodilators (deta-NONOate, pinacidil) and a vasoconstrictor (L-phenylephrine). The measurements were repeated after systemic infusion of L-NAME (NO synthase inhibition) and indomethacin (cyclo-oxygenase inhibition). RESULTS: The MBF response to acetylcholine was significantly lower in CBDL and tended to be lower in PPVL than in sham. L-NAME and indomethacin significantly decreased the MBF response to acetylcholine in all groups. The hyporeactivity to acetylcholine in CBDL and PPVL was maintained after L-NAME and indomethacin. The MBF response to pinacidil, deta-NONOate and phenylephrine, before and after NO synthase and cyclo-oxygenase inhibition, was lower in CBDL and PPVL than in sham. CONCLUSION: This is the first in-vivo study demonstrating an impaired response to endothelium-dependent and endothelium-independent vasodilators as well as vasoconstrictors in the mesenteric artery of animals with cirrhosis and portal hypertension. The generalised hyporeactivity suggests an abnormality on the vascular smooth muscle cell level. The hyporesponsiveness persisted after combined NO synthase and cyclo-oxygenase inhibition.

Diagnosis of portopulmonary hypertension in candidates for liver transplantation: a prospective study.

Portopulmonary hypertension represents a major risk factor for transplantation; therefore, preoperative detection is crucial. The aims of this study were to determine (1) whether Doppler echocardiography performed at evaluation is a reliable tool for detecting portopulmonary hypertension and (2) the incidence of acquired portopulmonary hypertension profile after evaluation. One hundred sixty-five patients had Doppler echocardiography and right heart catheterization at evaluation over a 9-year period. All patients had a prospective follow-up, and the results of catheterization at evaluation were compared with those obtained at the time of transplantation. Seventeen of 165 patients met the criteria for portopulmonary hypertension on Doppler echocardiography. Portopulmonary hypertension was confirmed by catheterization in 10 patients and ruled out in 7. There were no false negatives for echocardiography. Mean pulmonary artery pressure was significantly higher during the initial phase of transplantation than at evaluation (17.8 +/- 4.3 vs. 20.3 +/- 5.5 mm Hg, respectively, P <.0001), and there was no significant correlation between values obtained at these 2 time points. Three patients showed to have acquired portopulmonary hypertension profile while waiting for a graft within time intervals ranging from 2.5 to 5 months. In conclusion, Doppler echocardiography is a highly sensitive tool for detecting portopulmonary hypertension. However, because this technique has a poor positive predictive value, right heart catheterization is recommended for confirming portopulmonary hypertension. In addition, the absence of portopulmonary hypertension at evaluation does not exclude the occasional occurrence of acquired portopulmonary hypertension profile after listing.