Serial copper and ceruloplasmin levels in African newborns with emphasis on the sick and stable preterm infant, and their antioxidant capacities.

Abstract

Literature on serum copper (Cu) and its antioxidant protein (ceruloplasmin) in the African newborn is infrequent, and more reports are evident from developed or affluent societies. We, therefore, studied longitudinally our newborns to delineate their Cu and ceruloplasmin (CLP) status. All infants were born between July 1st, 1991 and June 30th, 1992 at the University of Maiduguri Teaching Hospital, Maiduguri, Nigeria. The preterm infants (PI) (gestational age < or = 36 weeks) were divided into 2 cohorts; A, sick and B, stable; commencing with n = 30 in each group. The groups were matched in respect to gender, gestational age, birthweight, Apgar scores and socioeconomic class. Cu levels were contemporaneously also determined in 30 (M:F, 17:13) stable full-term infants (appropriate-for-dates). Cu determination was made with atomic absorption spectrophotometry and CLP according to colorimetric P-phenylenediamine assay. Sick PI (cohort A) had significantly lower mean (SD) Cu and CLP levels at birth; 0.1 (0.2) micromol/ml and 0.5 (0.8) micromol/dl vs 0.6 (0.2) micromol/ml and 12.5 (1.2) micromol/dl in stable PI (cohort B), respectively; P < 0.05. Cu level was significantly increased by 4 weeks in cohort A; P < 0.001 (n = 25) and approached levels of the stable PI (0.7 (0.3) vs 0.8 (0.2) micromol/ml). Concerning CLP, however, catch-up of levels was delayed till 8 weeks, and a triphasic pattern of linear rise in Cu (both cohorts, but more prominent in A) and CLP (cohort A) was discernible by 24 weeks. The sick PI had mean (SD) serum CLP levels of 0.5 (0.8) micromol/dl, 5.9 (1.4), 15.2 (2.6), 17.3 (2.9), 21.2 (3.8), 25.1 (4.7) and 23.7 (3.8) micromol/dl at birth, 4, 8, 12, 20, and 24 weeks, respectively and were similar from 8 weeks in cohort B. Generally, CLP paralleled serum Cu levels. Cu levels in the full-term infant (FI) were higher at birth and became similar to PI's from 12 weeks, but were overtaken by levels in PI (both cohorts) at 24 weeks. The FI's Cu was significantly elevated by 8 weeks; mean (SD), 0.81 (0.16) micromol/ml vs 1.25 (0.19) micromol/ml; P < 0.01, paired t-test. Decreased growth rate, nonpitting pedal edema, exaggerated physiological anaemia and chronic lung disease were few morbidities noted in association with very low Cu and CLP levels (n = 15). Newborns with serum Cu and CLP>0.2 micromol/ml and >2.3 micromol/dl, respectively, did not have a poor outcome. It is tempting to suggest that absent serum CLP activity may portend a poor prognosis. Our findings (number albeit small) could be taken as a preliminary normative data for further comparisons.