RESUMO
BACKGROUND: Hypotrophic newborns in comparison with eutrophic newborns demonstrate a reduced blood platelet count and therefore may have haemostasis disorders. Expression of P-selectin (CD62P) on the surface of platelets is a marker of stimulated, activated blood platelets. The ability of platelets to react can be determined after the addition of the following activators: strong (thrombin) and weak (ADP). MATERIALS AND METHODS: We studied 48 hypotrophic newborns, 25 females and 23 males, weighing less than the 10th centile and 55 healthy, full-term newborns, 25 females and 30 males. Expression of CD62P on the surface of platelets was examined in the native state, after the addition of thrombin or ADP. RESULTS: Hypotrophic newborns exhibited almost double the percentage of platelets expressing CD62P compared with the control group, 4.21% versus 2.88%. After the addition of thrombin, the percentage was 31.5% versus 12.5%, p < 0.001, whereas after the addition of ADP, the percentage was 9.54% versus 4.5%, p = 0.002. CONCLUSIONS: Hypotrophic newborns are capable of greater platelet activation in comparison with healthy term newborns. However, gender does not affect the expression of P-selectin.
