Dr TIPOE, George Lim

Dr TIPOE, George Lim 鄭顏兒

B.A., M.D., Ph.D.

Associate Professor

Research Interests:

  • Role of nitric oxide and cylclooxygenase genes in inflammatory diseases of the lungs and liver
  • Molecular mechanisms involved in the adaptive response of the liver in chronic hypoxia
  • Role of oxidative stress involving lung and liver diseases
  • Cell biology and signal transduction molecules with emphasis on human diseases and clinical applications

Education / Training:

  • Associate Professor, Department of Anatomy, The University of Hong Kong, Hong Kong (since 1996 [tenured])
  • Assistant Professor, Department of Anatomy, The University of Hong Kong, Hong Kong (since 1994 [tenured])
  • Lecturer, Department of Anatomy, The University of Hong Kong, Hong Kong (since 1991)
  • Doctor of Philosophy, The University of Hong Kong, Hong Kong (1995)
  • Doctor of Medicine, University of the East, Manila (1980)
  • Bachelor of Arts, University of the East, Manila (1976)

Other Affiliations:

  • Honorary Professor, Department of Oral Pathology, Fourth Military Medical University, Xian, PRC (since 2000)

Research Description:

My research interest is on the mechanisms of inflammation, hypoxia and oxidative stress in the liver. Currently, my work concentrates on the role of antioxidants from medicinal herbs, phytochemical agents and multi-functional drugs (M30) on inflammation and oxidative stress in liver diseases, particularly in non-alcoholic liver disease (NAFLD). NAFLD is one of the leading causes of chronic liver injury across the world. It is also strongly related to other pathological conditions, including obesity, diabetes, cardiovascular diseases, and symptoms of metabolic syndrome. Pathogenesis of NAFLD remains not fully characterized but is generally attributed to the occurrence of insulin resistance, lipid metabolism dysfunction, oxidative stress, inflammation, and necro-apoptosis. Every potential therapeutic strategy should target one or some of these pathological events in the liver. Over the past decades, application of herbal treatment for NAFLD received increasing attentions due to its wide availability, low side effects, and proven therapeutic mechanisms and benefits. .

NAFLD is now recognized to be one of the risk factors in metabolic syndrome and also in liver cancer. The exact mechanism in the development of NAFLD remains poorly understood including the precise therapeutic management. Hence, my research investigates the signaling pathways that participate in the lipid dysfunction and imbalance, inflammation, autophagy and apoptosis. 

Postgraduate Research Projects Available:

  • The effects of chronic aerobic exercise and SAMC in non-alcoholic fatty liver disease. Xia Zhengyun (PhD candidate: Primary supervisor)
  • Skeletal muscle in non-alcoholic liver disease. Yu Qian (MPhil candidate: Primary supervisor)

Selected Publications:

  1. Guo R., Lin B., Pan J.F., Liong E.C., Xu A.M., Youdim M., Fung M.L., So K.F., Tipoe G.L. (2016). Inhibition of caspase-9 aggravates acute liver injury through suppression of  cytoprotective autophagy. Sci Rep. 6:32447. doi: 10.1038/srep32447.  PubMed PMID: 27580936.
  2. Guo R., Liong E.C., So K.F., Fung M.L., Tipoe G.L. (2015). Beneficial mechanisms of aerobic exercise on hepatic lipid metabolism in non-alcoholic fatty liver disease. Hepatobiliary Pancreat Dis Int. 14(2);139-44.
  3. Xiao J., Liong E.C., Huang H., On Tse W., Lau K.S., Pan J., Nanji A.A., Fung M.L., Xing F.,Tipoe G.L. (2015).Cyclooxygenase-1 serves a vital hepato-protective function in chemically induced acute liver injury. Toxicol Sci. 143;430-40. doi: 10.1093/toxsci/kfu244.
  4. Xiao J., Xing F., Huo J., Fung M.L., Liong E.C., Ching Y.P., Xu A., Chang R.C., So K.F., Tipoe G.L. (2014). Lycium barbarum polysaccharides therapeutically improve hepatic functions in non-alcoholic steatohepatitis rats and cellular steatosis model. Sci Rep. 7;4:5587. doi: 10.1038/srep05587.
  5. Xiao J., Wang J., Xing F., Han T., Jiao R., Liong E.C., Fung M.L., So K.F., Tipoe GL. (2014). Zeaxanthin dipalmitate therapeutically improves hepatic functions in an alcoholic fatty liver disease model through modulating MAPK pathway. PLoS One. 16;9:e95214. doi: 10.1371/journal.pone.0095214.
  6. Xiao J., Ho C.T., Liong E.C., Nanji A.A., Leung T.M., Lau T.Y., Fung M.L., Tipoe G.L. (2014). Epigallocatechin gallate attenuates fibrosis, oxidative stress, and inflammation in non-alcoholic fatty liver disease rat model through TGF/SMAD, PI3 K/Akt/FoxO1,and NF-kappa B pathways. Eur J Nutr. 53:187-99. doi: 10.1007/ s00394-013-0516-8.
  7. Xiao, J., Liong, E.C., Ching, Y.P., Chang, R.C.C.C., Fung, M.L., Xu, A., So, K.F. and Tipoe, G.L. (2013). Lycium barbarum polysaccharides protect rat liver from non-alcoholic steatoheaptitis-induced injury. Nutrition and Diabetes doi:10.1038/nutd.2013.22.
  8. Xiao, J., Guo, R., Fung, M.L., Liong, E.C., Chang, R.C.C., Ching, Y.P., and Tipoe, G.L. (2013b). Garlic-Derived S-Allylmercaptocysteine Ameliorates Nonalcoholic Fatty Liver Disease in a Rat Model through Inhibition of Apoptosis and Enhancing Autophagy. Evid-Based Compl Alt doi: 10.1155/ 2013/642920.
  9. Xiao, J., Guo, R., Fung, M.L., Liong, E.C., and Tipoe, G.L. (2013c). Therapeutic approaches to non-alcoholic fatty liver disease: past achievements and future challenges. Hepatob Pancreat Dis 12, 125-135.
  10. Nanji, A.A., Liong, E.C., Xiao, J., and Tipoe, G.L. (2013). Thromboxane inhibitors attenuate inflammatory and fibrotic changes in rat liver despite continued ethanol administrations. Alcoholism-Clinical and Experimental Research 37, 31-39.
  11. Xiao, J., Ching, Y.P., Liong, E.C., Nanji, A.A., Fung, M.L., and Tipoe, G.L. (2013). Garlic-derived S-allylmercaptocysteine is a hepato-protective agent in non-alcoholic fatty liver disease in vivo animal model. Eur J Nutr 52, 179-191.
  12. Fung, M.L., Tipoe, G.L. and Leung, P.S. (2012) Paracrine-autocrine mechanisms in the carotid body function at high altitude and in disease. Advances in high-altitude medicne and hypoxic physiolo in China. Edited by Sean Saunders, Fan Ming. Science (suppl), 66-68. (open access URLhttp://Science.imirus.com/Mpowered/book/ vscim12/i8/p1)
  13. Xiao, J., Liong, E.C., Ching, Y.P., Chang, R.C.C., So, K.F., Fung, M.L., and Tipoe, G.L. (2012). Lycium barbarum polysaccharides protect mice liver from carbon tetrachloride-induced oxidative stress and necroinflammation. J Ethnopharmacol 139, 462-470.
  14.  Xiao, J., Liong, E.C., Ling, M.T., Ching, Y.P., Fung, M.L., and Tipoe, G.L. (2012). S-allylmercaptocysteine reduces carbon tetrachloride-induced hepatic oxidative stress and necroinflammation via nuclear factor kappa B-dependent pathways in mice. Eur J Nutr 51, 323-
  15. Leung, T.M., Fung, M.L., Liong, E.C., Lau, T.Y.H., Nanji, A.A., and Tipoe, G.L. (2011). Role of nitric oxide in the regulation of fibrogenic factors in experimental liver fibrosis in mice. Histol Histopathol 26, 201-211.
  16. Tipoe, G.L., Leung, T.M., Liong, E.C., Lau, T.Y.H., Fung, M.L., and Nanji, A.A. (2010). Epigallocatechin-3-gallate (EGCG) reduces liver inflammation, oxidative stress and fibrosis in carbon tetrachloride (CCl4)-induced liver injury in mice. Toxicology 273, 45-52.

RGC/External Projects:

  • General Research Fund (RGC: 2016-2019) Defining the role of cyclooxygenase-1 in acute and chronic liver disease (Project no.17156516) HK$ 1,022,514.00 
  • HMRF (2015-2017): Therapeutic effects of Wolfberry (Lycium barbarum polysaccharides: LBP) in non-alcoholic fatty liver disease (NAFLD) animal models (Project No. 12133881) HK$ 923,440.00
  • I have obtained about HK$ 5.0 M external grants, HK$ 3.5 M internal grants and HK$ 0.5 M teaching grants since 1991.

Honours and Awards:

  • Faculty Teaching Medal for excellence in teaching at the LKS Faculty of Medicine, 2003

Key Offices:

  • Assistant Dean, Biomedical Science, Health Professional Curricula and Assessment (2013-2016)
  • Assistant Dean, Academic Networking and Student Affairs, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong (2008 -2013)

Editor Board of Scientific Journals:

  • Editorial Board Member, Scientific Reports (2015-2017)
  • Associate Editor, Anatomical Science Education (2007-2013)

Lab Personnel:

  • Xia Zhengyun is a PhD candidate (March, 2016 -February, 2019)
  • Yu Qian is a MPhil candidate (September, 2016 - August, 2018)