Association of cord blood platelet count and volume with hemoglobin in healthy term infants

A Physiologically-Based Pharmacokinetic Model to Predict Human Fetal Exposure for a Drug Metabolized by Several CYP450 Pathways

BACKGROUND

Pregnant women and their fetuses are exposed to numerous drugs; however, they are orphan populations with respect to the safety and efficacy of drugs. Therefore, the prediction of maternal and fetal drug exposure prior to administration would be highly useful.

METHODS

A physiologically-based pharmacokinetic (PBPK) model for nevirapine, which is metabolized by the cytochrome P450 (CYP) 3A4, 2B6 and 2D6 pathways, was developed to predict maternal and fetal pharmacokinetics (PK). The model was developed in both non-pregnant and pregnant women, and all physiological and enzymatic changes that could impact nevirapine PK were taken into account. Transplacental parameters estimated from ex vivo human placenta perfusion experiments were included in this PBPK model. To validate the model, observed maternal and cord blood concentrations were compared with predicted concentrations, and the impact of fetal clearance on fetal PK was investigated.

RESULTS

By implementing physiological changes, including CYP3A4, 2D6 and 2B6 inductions, we predicted a clearance increase of 21 % in late pregnancy. The PBPK model successfully predicted the disposition for both non-pregnant and pregnant populations. Parameters obtained from the ex vivo experiments allowed the prediction of nevirapine concentrations that matched observed cord blood concentrations. The fetal-to-maternal area under the curve ratio (0-24 h interval) was 0.77, and fetal metabolism had no significant effect on fetal PK.

CONCLUSIONS

The PBPK approach is a useful tool for quantifying a priori the drug exposure of metabolized drugs during pregnancy, and can be applied to evaluate alternative dosing regimens to optimize drug therapy. This approach, including ex vivo human placental perfusion parameters, is a promising approach for predicting human fetal exposure.

Prediction of human fetal pharmacokinetics using ex vivo human placenta perfusion studies and physiologically based models

AIMS

Pregnant women can be exposed to numerous drugs during the gestational period. For obvious ethical reasons, in vivo studies of fetal exposure to drugs are limited. Information about the transplacental transfer of drugs prior to their administration to pregnant women would be highly useful. In the present study, a novel approach was developed quantitatively predict or to predict the fetal exposure to drugs administered to the mother quantitatively.

METHODS

Transplacental parameters estimated from ex vivo human placenta perfusion experiments were implemented in pregnancy-physiologically based pharmacokinetic (p-PBPK) models in order to predict fetal PK. Thereafter, fetal PK profiles for two antiretroviral drugs, tenofovir (TFV) and emtricitabine (FTC) were simulated. These predictions were then compared to observed cord blood concentrations, to validate these models.

RESULTS

Parameters obtained from the ex vivo experiments enabled a good prediction of observed cord blood concentrations without additional a scaling factor. Moreover, a sensitivity analysis showed that fetal predictions were sensitive to changes in transplacental parameters values obtained ex vivo.

CONCLUSION

The integration of ex vivo human placental perfusion parameters in a p-PBPK model should be a promising new approach for predicting human fetal exposure to xenobiotics.

Impact of cesarean section on placental transfusion and iron-related hematological indices in term neonates: a systematic review and meta-analysis

Evidence suggests that cesarean section is likely associated with a reduced placental transfusion and poor hematological status in neonates. However, clinical studies have reported somewhat inconsistent results. We conducted a systematic review and meta-analysis to examine whether cesarean section affects placental transfusion and iron-related hematological indices. Pubmed, Web of Science, ScienceDirect, and Ovid Databases were searched for relevant studies published before April 9, 2013. Mean differences between cesarean section and vaginal delivery in outcomes of interests (placental residual blood volume; hematocrit level, hemoglobin concentration, and erythrocyte count in cord/peripheral blood) were extracted and pooled using a random effects model. We identified 15 studies (n = 8477) eligible for the meta-analysis. Compared with neonates born vaginally, those born by cesarean section had a higher placental residual blood volume [weighted mean difference (WMD), 8.87 ml; 95% confidence interval (CI), 2.32 ml-15.43 ml]; a lower level of hematocrit (WMD, -2.91%; 95% CI, -4.16% to -1.65%), hemoglobin (WMD, -0.51 g/dL; 95% CI, -0.74 g/dL to -0.27 g/dL) and erythrocyte (WMD, -0.16 × 10(12)/L; 95% CI, -0.30 × 10(12)/L to -0.01 × 10(12)/L). Subgroup analysis showed that the WMD for hematocrit in neonate's peripheral blood (-6.94%; 95% CI, -9.15% to -4.73%) was substantially lower than that in cord blood (-1.75%; 95% CI, -2.82%, -0.68%) (P value for testing subgroup differences <0.001). In conclusion, cesarean section compared with vaginal delivery is associated with a reduced placental transfusion and poor iron-related hematologic indices in both cord and peripheral blood, indicating that neonates delivered by cesarean section might be more likely affected by iron-deficiency anemia in infancy.

Mean platelet volume reflect hematopoietic potency and correlated blood group o in cord blood from healthy newborn

We evaluated the relationship between mean platelet volume (MPV) and characteristics of 10,577 cord blood (CB) units in a public CB bank in Korea. Blood group O has the highest MPV (P = 0.002). MPV correlated with CB volume (r = 0.121), Hb (r = 0.377), WBC (r = 0.111), TNCs (r = 0.110), CD34+ cell (r = 0.174), CD34+ cells/TNCs (r = 0.157), gestational age (r = −0.102), and birth weight (r = 0.023); (P < 0.001 in all). MPV may be one of the useful decision parameters of process priority in CB bank.

Hematologic profile of neonates with growth restriction is associated with rate and degree of prenatal Doppler deterioration

OBJECTIVE

To examine the relationship between hematologic parameters at birth and prenatal progression of Doppler abnormalities in fetal growth restriction (FGR).

METHODS

The study was a secondary analysis of FGR patients (abdominal circumference < 5th percentile and umbilical artery pulsatility index (UA-PI) elevation) with at least three examinations prior to delivery. Prenatal progression was classified as rapid, moderate or slow based on the interval between diagnosis and delivery and the extent of UA, middle cerebral artery and ductus venosus Doppler abnormalities. Associations between diagnosis-to-delivery interval, Doppler Z-scores, progression and hematologic parameters at birth were examined.

RESULTS

Of 130 patients, 54 (41.5%) had rapid, 51 (39.2%) moderate and 25 (19.2%) slow deterioration, delivering within 4, 6 and 9 weeks of diagnosis, respectively. The strongest association of moderate and rapid deterioration was with a low platelet count (r2  = 0.37 and 0.70, respectively; P < 0.0001). In patients with moderate deterioration, platelet count correlated inversely with UA-PI (ρ = -0.44, P = 0.001) and was lowest when end-diastolic velocity was absent. With rapid progression, platelet count correlated inversely with nucleated red blood cell count (ρ = -0.51, P < 0.001) but no longer with UA-PI.

CONCLUSION

Our observations suggest a relationship between prenatal clinical progression of FGR and hematologic abnormalities at birth. Accelerating cardiovascular deterioration is associated with decreased platelet count, which can be explained by placental consumption or dysfunctional erythropoiesis and thrombopoiesis.