Neonatal mononuclear cell metabolism: further evidence for diminished monocyte function in the neonate.
The metabolic capacity of neonatal monocytes was compared to the metabolic capacity of adult monocytes by two entirely different methods: the selective diminution of monocyte contamination of whole mononuclear cells and the isolation of relatively purified populations of monocytes. Monocyte removal from whole mononuclear cells produced a diminution in the pyruvate kinase (PK) activity (from 28.6 +/- 1.1 to 15.6 +/- 1.2 nmoles/min/10(7) cells) and an increase in adenosine triphosphate (ATP) content (from 7.9 +/- 1.0 to 9.5 +/- 0.8 nmoles/10(7) cells) in adult cells. No change in PK activity (from 13.5 +/- 1.3 to 14.0 +/- 1.3) was observed in cord cells, but the ATP content of cord cells was higher after monocytes depletion (from 4.7 +/- 0.5 to 6.2 +- 0.7). The suggestion of metabolic vulnerability was confirmed by metabolic analysis of isolated adult and cord monocytes. The PK activity of adult monocytes was greater than that of cord monocytes (57 +/- 9 and 25 +/- 0.3, respectively) and the ATP content of adult monocytes (5.7 +/- 0.2) was greater than that of cord monocytes (2.3 +/- 0.1). The data confirm prior observations of diminished energy metabolism in neonatal mononucler cells and suggest that the metabolic perturbations may, in part, correlate with functional immaturity of the neonatal monocyte.
D000255:Adenosine Triphosphate / Q000032:analysis; D000328:Adult; D006801:Humans; D007109:Immunity; D007231:Infant, Newborn; D007773:Lactates / Q000096:biosynthesis; D008214:Lymphocytes / Q000378:metabolism; D009000:Monocytes / Q000032:analysis / Q000201:enzymology*; D011770:Pyruvate Kinase / Q000378:metabolism*
D007773:Lactates; D000255:Adenosine Triphosphate; D011770:Pyruvate Kinase