Journal of Pediatric Gastroenterology & Nutrition:
Letters to the Editor
University of Bari Bari, Italy
To the Editor:
We read with interest the article “Influence of gestational age, cesarean section, and type of feeding on fecal human α-defensins 2 and tumor necrosis factor-α” by Richter et al (1). Following this publication, we would like to report our longitudinal evaluation of human β-defensins 2 (hβD) and tumor necrosis factor-α (TNF-α) in stools of healthy preterm and term newborns, in relation to the method of delivery (cesarean section [CS] vs vaginal delivery [VD]), gestational age (GA), and type of feeding (breast-fed [BF], formula-fed [FF], breast- and formula-fed [BF and FF]).
We enrolled 39 preterm newborns (G1) (mean GA 31.2; mean birth weight 1870 g; 38 CS; 1 VD; 4 BF; 13 BF + FF; 22 FF) and 29 term newborns (G2) (mean GA 39.3; mean birth weight 3306 g; 12 CS; 17 VD; 23 BF; 2 BF + FF; 4 FF), and stool samples were collected on days 15, 30, and 60 in the G1 group and on days 3, 7, 15, and 30 in the G2 group. All of the samples were frozen at −20° until analysis. hβD and TNF-α were analyzed by commercially available enzyme-linked immunosorbent assay kit (Immunodiagnostic, Bensheim, Germany; values: nanograms per milligram faeces). For statistical analysis, data were analyzed with the SAS package (SAS Institute, Cary, NC). Repeated measures analysis of variance was performed to evaluate the effect of time collection on TNF-α and hβD values in the 2 studied groups. Two-way analysis of variance models were used to evaluate the effect of delivery and feeding. A regression model was built to evaluate TNF-α and hβD values according to GA.
We found that mean TNF-α values did not vary during the period of stool collection both in preterm (P = 0.12) and in term newborns (P = 0.34), but TNF-α was higher in preterm a newborns (P < 0.001). TNF-α values also decrease with GA (P = 0.02). No differences were found related to both delivery (P = 0.11) and type of feeding (at 1 month) (P > 0.05).
Mean hβD values significantly differ both in G1 (increase from days 15–30 and then decrease until day 60; P < 0.0001) and in G2 (decrease from days 3–15 followed by stabilization until d30; P < 0.0001, as previously reported (2)). No significant differences in hβD values were found related to the method of delivery (P = 0.11) or type of feeding (after 1 month) (P > 0.05). Mean hβD values increased with GA, as reported by Richter et al (1).
We conclude that hβD and TNF-α are present in intestinal lumen in both preterm and term newborns. TNF-α was higher in preterm newborns and inversely related to GA. hβD increased from days 15 to 30 in preterm newborns and it is positively correlated to GA.
We have found different results compared with Richter et al (1), probably related to our longitudinal collection (days 3, 7, 15, 30, and 60) of stool samples. It could be interesting to understand whether higher TNF-α values and hβD increasing values in preterm newborns are the effect of the inflammatory condition of the gut or that of natural defense mechanisms.
1. Richter M, Topf HG, Groschl M, et al. Influence of gestational age, cesarean section, and type of feeding on fecal human α-defensins 2 and tumor necrosis factor-α. J Pediatr Gastroenterol Nutr
2. Campeotto F, Baldassarre M, Laforgia N, et al. Fecal expression of human β-defensin-2 following birth. Neonatology