CULTURE OF ADULT HUMAN ISLET PREPARATIONS WITH HEPATOCYTE GROWTH-FACTOR AND 804G MATRIX IS MITOGENIC FOR DUCT CELLS BUT NOT FOR BETA-CELLS

It has recently been reported that human adult beta-cells proliferate during culture on an extracellular matrix prepared from rat 804G cells and in the presence of hepatocyte growth factor (HGF) (6). The presen t study compares the mitogenic effect of this condition on human beta- cells and on neighboring non-endocrine duct cells. Islet cell-enriched fractions were prepared from adult human organ donors and cultured in suspension or 804G matrix, with or without HGF. The combination of 80 4G matrix and HGF increased the number of 5-bromo-2'-deoxyuridine-posi tive (BrdU(+)) cells within 48 h reaching a maximum after 4 days. In s elections, virtually all BrdU(+) cells were negative for insulin or gl ucagon and for preproinsulin mRNA but expressed the ductal cell marker s cytokeratin 19 and 7, carbonic anhydrase-II, and carbohydrate antige n 19-9. After 4 days of culture, the cytokeratin 19(+) ductal cells ex hibited a BrdU-labeling index of 30% (P < 0.01 vs. 2% without HGF and matrix), whereas <0.1% of insulin-positive and <1% of glucagon-positiv e cells were labeled. Formation of bilayers with ductal cells covering the endocrine cells may cause erroneous interpretation on double posi tivity in unsectioned tissue. It is concluded that culture of human is let cell preparations with HGF and 804G matrix stimulates the prolifer ation of the duct cells but not of the underlying beta-cells.