Reticulocyte enrichment of zinc protoporphyrin/heme discriminates impaired iron supply during early development.
In infants and children, elevated whole blood zinc protoporphyrin/heme (ZnPP/H) measures iron-deficient (ID) erythropoiesis. Because immature erythrocytes are less dense than mature erythrocytes, we hypothesized that the sensitivity of ZnPP/H is improved if measured in the least dense cells. Blood was collected from control suckling, mildly and severely ID suckling rats. Cord blood was collected after uncomplicated pregnancies (control), diabetic pregnancies (severe ID) and after pregnancies at-risk for iron deficiency (mild ID). ZnPP/H was measured before and after a two-step density centrifugation to obtain the lightest 6.25% of erythrocyte (top fraction). The difference between whole blood and top fraction was defined as DeltaZnPP/H. In rats, although the whole or top ZnPP/H differed by postnatal age, DeltaZnPP/H was greatest after the interval with least body iron accrual. In either rats or humans with mild ID, whole blood ZnPP/H was similar to, but DeltaZnPP/H was greater than controls. In rats and newborn humans, DeltaZnPP/H is more sensitive than whole blood ZnPP/H in identifying conditions associated with impaired erythrocyte iron delivery and may become a useful tool in measuring erythrocyte iron incorporation in early development.
Blohowiak
Sharon E
SE
Department of Pediatrics, University of Wisconsin, Madison, Wisconsin 53715, USA.
Chen
Melinda E
ME
Repyak
Kristin S
KS
Baumann-Blackmore
Nicole L
NL
Carlton
David P
DP
Georgieff
Michael K
MK
Crenshaw
Thomas D
TD
Kling
Pamela J
PJ
D000367:Age Factors; D018798:Anemia, Iron-Deficiency / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D000751:Anemia, Neonatal / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D000818:Animals; D000831:Animals, Newborn; D000833:Animals, Suckling; D015415:Biomarkers / Q000097:blood; D004920:Erythropoiesis; D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D006418:Heme / Q000378:metabolism*; D006801:Humans; D007231:Infant, Newborn; D007501:Iron / Q000378:metabolism*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000097:blood; D011524:Protoporphyrins / Q000097:blood*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012156:Reticulocytes / Q000378:metabolism*; D012720:Severity of Illness Index
D015415:Biomarkers; D011524:Protoporphyrins; C017803:zinc protoporphyrin; D006418:Heme; D007501:Iron