PubMed · 2922383
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E Jimenez, M Vogel. 1989. [Comment on a previous article].. https://pubmed.ncbi.nlm.nih.gov/2922383/
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The chick chorioallantoic membrane (CAM) is a valuable model for evaluating angiogenesis and vasculogenesis. Our purpose was to characterize the formation of the CAM vasculature, in particular the capillary plexus, between days five and six after fertilization and to examine the mode of action of cytochalasin D and suramin on vascular development during this interval. The CAM increased 20-fold in size between days five and six, during which time the capillary plexus forms by both migration of mesodermal blood vessels toward the ectoderm and by the formation of new vessels from angioblasts near the ectoderm. Between days five and six, the CAM becomes thinner, and the density of the mesodermal cells decreases. To determine the mode of action of anti-angiogenic drugs on the day five to day six CAM, various concentrations of cytochalasin D or suramin were added directly to day five CAMs, and their effects were evaluated on day six. Both drugs significantly inhibited CAM growth, altered branching patterns of the major vessels, decreased area of the major vessels, and inhibited the formation of the capillary plexus by inhibiting both vasculogenesis and the migration of mesodermal blood vessels to the ectoderm. Cytochalasin D also inhibited compartmentalization of the plexus. Cytochalasin D and suramin were inhibitory at similar doses. This study provides new information on early CAM development, establishes the mode of action and dose dependency of cytochalasin D and suramin on day five to day six CAMs, and demonstrates that the day five to day six CAM provides a useful assay to examine the effect of anti-angiogenic drugs on blood vessel development, including capillary plexus formation.
The observation that the addition of deuterium oxide to tissue culture cell harvests stabilized trivalent oral poliovirus vaccine prompted us to examine the effect of deuterium oxide on stabilization of other licensed and experimental live viral vaccines. The most striking effect afforded by deuterium oxide was on stabilization of live, attenuated influenza A and B vaccine candidates grown in the allantoic cavity of embryonated eggs. Thermostabilization with deuterium oxide is much greater than seen with standard stabilization of these live influenza vaccines with sucrose-phosphate-glutamate. Subsequently, we have shown that a similar, stabilization is provided by diluting egg allantoic fluid in water or minimal essential medium. The mechanism of action has been explored but remains uncertain. The implications of being able to stabilize influenza after harvesting from eggs have practical application for utilization of live influenza vaccines and provides a possible way to increase and standardize the potency of inactivated vaccines that may partially degrade in the inimical environment of allantoic fluid during growth and before final vaccine purification and stabilization.
The effects of heparin on angiogenesis are controversial, with some studies claiming stimulatory and other studies claiming inhibitory effects. Since heparin in human plasma is complexed with basic peptides and proteins, we studied the angiogenic effect of complexes resulting by mixing poly-L-lysine (a basic heparin-binding polypeptide) and heparin. Angiogenesis was investigate by chorioallantoic membrane assay. In specimens treated with PBS (negative control), or poly-L-lysine, no significant vascular reaction was detectable. Heparin induced only moderate angiogenic response. However, neutral complexes purified from a mixture of poly-L-lysine and heparin (20/1, w/w) induced a very strong angiogenic response. These results demonstrate that the angiogenic effect of heparin was associated with neutralization of electric charge when the polysaccharide was complexed with a basic peptide.