Professor Hans Zoellner

Biography

Prof Zoellner graduated in Dentistry at the University of Sydney in 1983, and after three years of general practice in Wagga Wagga returned to the Institute of Dental Research at the University of Sydney for PhD studies of the vasculature in chronic periodontitis. He then spent from 1990 to 1992 as a post-doctoral scientist in the Department of Medicine, Royal Melbourne Hospital studying the fibrinolytic and cytokine synthetic activity of vascular endothelium and smooth muscle cells. A Lise Meitner International Research Fellowship awarded by the Austrian Funds for the Promotion of Science supported two years of independent research in the Department of Physiology at the University of Vienna from 1993 to 1994. In 1995, Prof Zoellner returned to the University of Sydney as a lecturer in Oral Pathology, working under Professor DM Walker who was the founder of the discipline in Sydney. From 1995 to 2000, Prof Zoellner expanded his experience in Pathology by serving part time as a junior registrar in Anatomical Pathology at the Institute for Clinical Pathology and Medical Research, while separately developing his continuing research interests and curriculum in Oral Pathology. In 2003, responding to ongoing inequity in access to dental services and under-resourcing of the public dental services, Prof Zoellner joined with several colleagues in the formation of the Association for the Promotion of Oral Health (APOH), of which he was the Chairman till 2014. APOH played a significant role in driving public debate and policy in oral health. In 2005, Prof Zoellner became head of the discipline of Oral Pathology on the retirement of Professor Walker and he currently continues in that role. From June 2013 to December 2014, Prof Zoellner carried out sabbatical research in the Cell Biology Program of the Memorial Sloan Kettering Cancer Center in New York, together with Dr MAS Moore.

Research Interest

A central theme emerging from Prof Zoellner's PhD studies, was the question of how individual endothelial cells in the microcirculation self-organize for optimal function, with the microvasculature considered as an interesting biological system with which to study the intimate relationship between biological form and function. This underlying question has been addressed through examination of tissues in chronic inflammation, wound healing, oral submucous fibrosis and cancer, all conditions where the microvasculature undergoes substantial structural and functional change. Shuttling between human, animal and cell culture experimental systems has helped to focus interests on biologically relevant questions. Because of the important role of cytokines and fibrinolytic proteins in a wide variety of pathological and remodelling processes, much effort has been directed to the study of vascular cells in both synthesis of and response to these potent biological agents. Syergystic interactions between cytokines have been of particular interest, as these seem most likely to have greatest biological relevance. Endothelial apoptosis was identified as a key mechanism in microvascular remodeling, and regulation of this by cytokines has been studied. A significant discovery was of a potent anti-apoptotic activity in a serum albumin protein domain exposed by intramolecular movement and proteolytic cleavage, and mediated via a G-protein coupled endothelial receptor. A surprising discovery of wound healing with fat instead of scar tissue formation preluded the wider more recently recognized role of stem cells in wound healing. A clinically significant study completed in collaboration with Dr S Cox in Oral Surgery, showed that patients suffering with oral submucous fibrosis, a slowly progressive scarring disease of the mouth which ultimately makes eating and speech enormously difficult, can be much improved using a simple physiotherapeutic approach. The diagnostic value of complete laser excision of oral pre-malignant lesions, compared with traditional incisional scalpel biopsy, is also under study. Interaction between cancer and vascular endothelial cells, as well as with fibroblasts has been studied, and has led to our recent key report that cancer cell diversity can be increased by a process whereby normal cells inject cytoplasm into the cancer cells, a mechanism which Prof Zoellner has termed ‘ananka-rheosis’, from the Greek for ‘to compel’ being ‘anagkazo’, and ‘flow’ being ‘reo’. The relationship between biological form and function has been further studied by finite element analysis with regard to tooth eruption and bony remodelling. Of particular note, is our discovery that patterns of tension and compression in the tissues surrounding unerupted teeth, may account for the way that teeth emerge into the mouth.