Cord blood serum-based eye drops: the impact of donor haematological and obstetric factors on the variability of epidermal growth factor levels

Abstract

Background: Cord blood serum (CBS)-based eye drops are successfully used in corneal epithelial wound healing and are prepared to supply a known amount of epidermal growth factor (EGF). Product standardisation includes expensive EGF dosage in all cord blood (CB) units. The influence of donor obstetric and haematological characteristics on EGF content was evaluated, to exclude unsuitable CBS and pre-select those CB units able to provide the correct EGF supply for healing corneal wounds.

Materials and methods: Data were retrospectively collected from 135 donors included in the Emilia Romagna Cord Blood Bank records. Obstetric characteristics, parity and gestational age of the mother, sex, birth weight and Apgar score of the neonate, placental weight, duration of labour and mode of delivery were considered. Haematological characteristics, CD34+ cell number, and total nucleated cell, white blood cell and platelet counts were recorded. EGF content in CB units was estimated by enzyme-linked immunosorbent assay. Statistical evaluation was performed by Mann-Whitney unpaired and Student's t tests. Correlations between variables were evaluated by using Pearson's (r) or Spearman's (ρ) correlation coefficients.

Results: EGF content was significantly higher in CBS from donors aged <30 years and after vaginal deliveries as compared with scheduled Caesarean sections (1,386±580 vs 1,106±391 pg/mL; P=0.002). EGF content was significantly correlated with duration of labour (r=0.45; P=0.0001), number of CD34+ cells/mL (r=0.3; P=0.002) particularly in vaginal deliveries (r=0.36; P=0.003), mother's age (-0.25; P=0.005), neonate's birth weight (r=0.27; P=0.005), and total nucleated cell (r=0.25; P=0.006), white cell (r=0.29; P=0.001) and platelet (r=0.24; P=0.009) counts. No significant correlations were found between EGF content and parity, gestational age, placental weight, neonate's sex or Apgar scores.

Discussion: EGF levels are higher in CB units from younger mothers (<30 years), with longer labour duration (>6 hours), and higher CD34+ cell content (>0.05×10(6)/mL). In order to optimise the preparation and costs of CBS-based eye drops, pre-selection of CB units is recommended.

Figures

Figure 1

EGF concentration in CBS obtained after different modes of delivery. A great variability in EGF content was found among the samples obtained after both vaginal delivery and Caesarean section. A statistically significant difference was demonstrated in EGF content between the two groups, with the higher content found in CBS from vaginal deliveries.

Figure 2

Correlation between EGF and CD34+ cell content in CBS samples. A statistically significant correlation was found between the two parameters when all the samples were analysed together (A). When analysing the correlation in samples divided according the method of delivery of the neonate, significance increased in the vaginal delivery group (B) but decreased in the Caesarean section group (C).

Figure 3

Correlation between EGF content in CBS and duration of labour in hours (A) and between EGF content in CBS and neonatal weight in grams (B). A strong, statistically significant correlation was found in both cases.

Figure 4

Correlation between EGF content in CBS and some haematological parameters: total nucleated cells before volume reduction/μL CB sample (TNCb) (A), total nucleated cells after volume reduction/μL CB sample (TNCa) (B), platelets/mL CB sample (C). A statistically significant correlation was found in all cases.