Plasma protease inhibitors in premature infants: influence of gestational age, postnatal age, and health status.
In newborn infants, the influence of gestational age (GA), postnatal age (PA), and health status on the plasma protease inhibitors alpha 2-macroglobulin (alpha 2-M), alpha 1-antitrypsin (alpha 1-AT), C1 esterase inhibitor (C1E-INH), alpha 2-antiplasmin (alpha 2-AP), and antithrombin III (AT-III) was investigated. Inhibitor levels were measured by radial-immunodiffusion and expressed as a percentage of pooled plasma from adults (mean +/- SEM). In total, 54 premature infants (28-36 weeks gestation) were classified at birth as healthy (N = 22) (IV fluids, antibiotics only) or sick (N = 32) (all other support, but excluding infants with disseminated intravascular coagulation (DIC] and studied on Days 1 and/or 7 of life. Healthy term infants (N = 18) and infants with DIC (N = 10) were studied on Day 1 only. All inhibitors except C1E-INH increased with increasing gestational age (P less than 0.01). In healthy premature infants all inhibitor levels reached the normal adult range by 1 week of age. In contrast, at 1 week of age, sick infants had lower levels of alpha 2-M and alpha 2-AP, and higher levels of alpha 1-AT compared to healthy infants (P less than 0.01). The presence of DIC depressed all of the inhibitors on Day 1 except alpha 1-AT when compared to healthy controls (P less than 0.01). Thus, gestational age, postnatal age, and health status all significantly influenced the levels of these plasma protease inhibitors.
D000990:Antithrombin III / Q000032:analysis; D003174:Complement C1 Inactivator Proteins / Q000097:blood; D005865:Gestational Age; D006304:Health Status; D006801:Humans; D005779:Immunodiffusion; D007231:Infant, Newborn; D007234:Infant, Premature; D011480:Protease Inhibitors / Q000097:blood*; D000515:alpha 1-Antitrypsin / Q000032:analysis; D000979:alpha-2-Antiplasmin / Q000032:analysis; D000511:alpha-Macroglobulins / Q000032:analysis
D003174:Complement C1 Inactivator Proteins; D011480:Protease Inhibitors; D000515:alpha 1-Antitrypsin; D000979:alpha-2-Antiplasmin; D000511:alpha-Macroglobulins; D000990:Antithrombin III