Liver diseases affect millions of people worldwide. In most developed countries, the incidence of viral hepatitis is waning as a result of modern advances in disease prevention, diagnosis, and therapies. Expanded programmes for systematic immunisation against hepatitis B virus have also significantly brought down the number of new cases in many countries, including China. In contrast, with the improvement in living standards, the prevalence of metabolic liver diseases including non-alcoholic fatty liver disease and alcohol-related liver disease is set to rise, ultimately leading to more cases of end-stage liver diseases (liver failure, cirrhosis, and liver cancer). Over the past 30 years, visionary governments of major nations have provided strong incentives for basic/clinical research, vaccination programmes, and drug discovery and development in the field of hepatology. To get rid of her unflattering title as the ''leader in liver diseases", China has also made a serious effort to initiate nationwide preventive measures for liver diseases, global partnerships, and mentoring programmes for young hepatologists. Instrumental to such progress is the continuous support of the National Natural Science Foundation of China (NSFC), which has helped hepatology to thrive in virtually all research directions within the country. In this article, we seek to provide stimulating glimpses into the evolving liver disease epidemiology, institutional research profiles, funding landscape, and drug development trends in China, with an attempt to compare her status and achievements with those of the United States, European countries, and Japan.

Background: Angiogenesis is a dynamic process that involves expansion of a pre-existing vascular network that can occur in a number of physiologic and pathologic settings. Despite its importance, the origin of the new angiogenic vasculature is poorly defined. In particular, the primary subtype of endothelial cells (capillary, venous, arterial) driving this process remains undefined. Methods: Endothelial cells were fate-mapped using genetic markers specific to arterial, capillary cells. In addition, we identified a novel venous endothelial marker gene ( Gm5127 ) used it to generate inducible venous endothelial-specific Cre and Dre driver mouse lines. Contributions of these various types of endothelial cells to angiogenesis were examined during normal postnatal development and in disease-specific setting. Results: Using a comprehensive set of endothelial subtype-specific inducible reporter mice, including tip-, arterial- and venous- endothelial reporter lines, we showed that venous endothelial cells are the primary endothelial subtype responsible for the expansion of an angiogenic vascular network. During physiologic angiogenesis, venous endothelial cells proliferate, migrating against the blood flow, and differentiating into tip, capillary and arterial endothelial cells of the new vasculature. Using intravital 2-photon imaging, we observed venous endothelial cells migrating against the blood flow to form new blood vessels. Venous endothelial cell migration also plays a key role in pathologic angiogenesis. This was observed both in formation of arterio-venous malformations in mice with inducible endothelial-specific Smad4 deletion mice and in pathologic vessel growth seen in oxygen-induced retinopathy. Conclusions: Our studies establish venous endothelial cells are primary endothelial subtype responsible for the normal expansion of vascular networks, formation of arterio-venous malformations and pathologic angiogenesis. These observations highlight the central role of the venous endothelium in normal development and disease pathogenesis.

MicroRNAs (miRNAs) are post-transcriptional inhibitor regulators of gene expression that act by directly binding complementary mRNA and are key determinants of cancer initiation and progression. In this study, we revealed a role for the tumor-suppressor miRNA miR-503 in endometrioid endometrial cancer (EEC) cells. The miR-503 expression level gradually decreases across normal endometrial tissues, endometrial tissues with complex atypical hyperplasia, and EEC tissues. A relatively high level of miR-503 in EEC tissues indicates a longer survival time in EEC patients. The expression of a cell cycle-associated oncogene encoding cyclin D1 (CCND1) was inversely correlated with miR-503 expression in EEC tissues and cell lines. CCND1 has a binding sequence of miR-503 within its 3′ untranslated region, and was confirmed to be a direct target of miR-503 by the fluorescent reporter assays. Increasing the miR-503 level in EEC cells suppressed cell viability, colon formation activity and cell-cycle progression, and the inhibited oncogenic phenotypes induced by miR-503 were alleviated by ectopic expression of CCND1 without the untranslated region sequence. Furthermore, in vivo studies also suggested a suppressive effect of miR-503 on EEC cell-derived xenografts. miR-503 increased in cell cycle-arrested EEC cells, and was restored to a normal level in EEC cells after cell cycle re-entry, while CCND1 displayed the opposite expression pattern. Collectively, this study suggested that miR-503 plays a tumor-suppressor role by targeting CCND1. Abnormal suppression of miR-503 leads to an increase in the CCND1 level, which may promote carcinogenesis and progression of EEC.

Endothelial cells differ from other cell types responsible for the formation of the vascular wall in their unusual reliance on glycolysis for most energy needs, which results in extensive production of lactate. We find that endothelium-derived lactate is taken up by pericytes, and contributes substantially to pericyte metabolism including energy generation and amino acid biosynthesis. Endothelial-pericyte proximity is required to facilitate the transport of endothelium-derived lactate into pericytes. Inhibition of lactate production in the endothelium by deletion of the glucose transporter-1 (GLUT1) in mice results in loss of pericyte coverage in the retina and brain vasculatures, leading to the blood-brain barrier breakdown and increased permeability. These abnormalities can be largely restored by oral lactate administration. Our studies demonstrate an unexpected link between endothelial and pericyte metabolisms and the role of endothelial lactate production in the maintenance of the blood-brain barrier integrity. In addition, our observations indicate that lactate supplementation could be a useful therapeutic approach for GLUT1 deficiency metabolic syndrome patients.