A hemostasis activating factor (HAF) in subcutaneous tissue extracts: Effects on morphologic platelet changes, platelet retention and platelet aggregation

Abstract

Extracts from both human and porcine subcutaneous tissue were obtained by extraction with propanol. After centrifugation the intermediate zone contained potent platelet stimulating activity. Platelet morphology changed by sphering and pseudopode formation within seconds after incubation of these lipoprotein containing tissue extracts with freshly drawn blood. The tissue extracts were active in dilutions up to 1:1000. At room temperature and at 6°C the extracts lost their activity after 14 - 21 days. At −17°C, −60°C or freeze dried they retained their activity for more than 45 days. At 37°C the stimulating effects on platelets in citrated blood was reversible within 10 minutes. The tissue extracts strongly enhanced platelet retention in glass bead columns. They did not induce platelet aggregation but increased the sensitivity to ADP and collagen markedly soon after blood sampling. The addition of small amounts of tissue extracts to PRP, which aggregated spontaneously in PAT III led to spontaneous aggregation 10 minutes after blood sampling. No such effect was observed with spontaneously non-aggregating PRP. Apparently the tissue extracts shortened the time dependent changes in aggregation response from 30 – 90 to less than 10 minutes. The lipoprotein responsible for these effects probably stimulates primary hemostasis and is therefore named “Hemostasis Activating Factor” (HAF).