The Department of Cell Biology (CYTO-VUB) is specialized in molecular and cellular liver research, with a main focus on the (patho)biology of hepatic stellate cells and liver progenitor cells. Prof. A. Geerts contributed to the first paper on isolation, purification and culturing of hepatic stellate cells (1) and is the author of a side scatter activated cell sorting method to purify freshly isolated hepatic stellate cell up to 95 - 100% (2). CYTO-VUB also has long term experience in isolating, purifying and culturing liver sinusoidal endothelial cells and Kupffer cells. The group has the required expertise and know-how to perform molecular and morphological studies on isolated cells and on tissues. Hepatic stellate cells surround the endothelial lining of sinusoids in the liver. They play important roles in : (i) vitamin A metabolism, (ii) formation of extra cellular matrix, (iii) pathogenesis of fibrosis and cirrhosis, (iv) regulation of flow and pressure in the sinusoids, (v) secretion of growth factors and cytokines in normal liver and under physiological and pathological regeneration, (vi) progression of primary or metastatic tumor growth and (vii) neural signal propagation. Besides these classical functions that are attributed to hepatic stellate cells, it appears that a subpopulation of these cells plays a role in formation of the hepatic progenitor cell niches. References: (1) de Leeuw, A. M., S. P. McCarthy, A. Geerts, and D. L. Knook. Purified rat liver fat-storing cells in culture divide and contain collagen. Hepatology 1984, 4:392-403. (2) Geerts, A., T. Niki, P. De Bleser, D. De Craemer, K. Van den Berg, J. M. Lazou, G. Stange, and M. Van De Winkel. Purification of hepatic stellate cells by side scatter activated cell sorting. Hepatology 1998, 27, 590 - 598.