Lothar Schweigerer

Basic fibroblast growth factor is synthesized in cultured retinal pigment epithelial cells

Cultured cells derived from bovine retinal pigment epithelium (RPE) express the basic fibroblast growth factor (bFGF) gene and they contain 3.7 and 7.0 kb bFGF gene transcripts which are translated into immunoreactive bFGF of Mr 17,500 and 18,000, respectively. The RPE cell-derived bFGF is bioactive, i.e., it can stimulate the proliferation of capillary endothelial cells and the stimulation of cell proliferation is blocked by anti-bFGF antibodies. We suggest that RPE cell-derived bFGF may be involved in the repair mechanisms following retinal injury and in the intravitreal pseudoneoplastic proliferation of the injured RPE.

Tumor necrosis factor inhibits the proliferation of cultured capillary endothelial cells

We have examined the effect of tumor necrosis factor (TNF) on the proliferation of capillary endothelial cells derived from brain or adrenal cortex. In both cell types, TNF inhibits basal as well as basic fibroblast growth factor (bFGF)-stimulated cell proliferation. TNF induces an additional cytotoxic effect in bFGF-stimulated, but not in unstimulated, capillary endothelial cells. These results suggest that TNF could act as a negative regulator of angiogenesis in vivo and further, that TNF might induce selective cytotoxicity of capillary endothelial cells stimulated by tumor-derived bFGF. These results could explain why TNF induces hemorrhagic necrosis of certain, solid tumors.

Basic fibroblast growth factor: Expression in cultured cells derived from corneal endothelium and lens epithelium

We have examined the possible expression of fibroblast growth factor in cultured cells derived from bovine lens epithelium and corneal endothelium. Lens epithelial, but not corneal endothelial, cells were found to express the acidic fibroblast growth factor (aFGF) gene, whereas both cell types express the gene encoding basic fibroblast growth factor (bFGF), a related mitogen. Expression of bFGF was further examined. Both corneal endothelial and lens epithelial contain 3.7 and 7.0 k bFGF gene transcript, which are translated into material closely related, if not identical with bFGF. Essentially all of the bFGF-like material is bioactive, i.e. it can stimulate the proliferation of capillary endothelial or corneal endothelial cells and the stimulation is blocked by anti-bFGF antibodies. Our results indicate that bFGF derived from corneal endothelial and lens epithelial cells may act as a paracrine and autocrine growth factor in both cell types. Thus, bFGF present in both cell types may play an important role in the proliferation of injured or transformed ocular tissues.

Basic fibroblast growth factor as a growth inhibitor for cultured human tumor cells.

Basic fibroblast growth factor (bFGF) stimulates the proliferation of many cells and it is found in a wide variety of normal or transformed tissues. As demonstrated here, bFGF is also present in cultured human Ewings sarcoma cells. Unexpectedly, however, bFGF isolated from these cells inhibits their own proliferation, indicating that bFGF can act as an endogenous (autocrine) growth inhibitor for cultured Ewings sarcoma cells. Since bFGF also inhibits the proliferation of some further tumor cells, but stimulates that of others, it can be considered a bifunctional regulator of tumor cell proliferation. The autocrine growth-inhibitory effect of bFGF in Ewings sarcoma cells may explain the low mitotic activity of Ewings sarcomas.

Opioid peptides: do they have immunological significance?

Abstract Almost a decade after the discovery of the endogenous opioids, their physiological role is still nuclear. Hansjorg Teschemacher and Lothar Schweigerer describe recent studies which indicate that opioid peptides might have immunological significance. These peptides can modulate several immune functions and appear to be constituents of the immune system themselves. It is possible that opioid peptides are involved in the immune response to stress or even in the immune defence against neoplastic disease.