Review for 10.1186/1471-230X-9-92 (2009)

Reviewer's report
Title:The effect of enteral and parenteral feeding on secretion of orexigenic
peptides in infants
Version: 1Date:16 June 2009
Reviewer: Thomas Brzozowski
Reviewer's report:
This study describes the effect of feeding on the levels of ghrelin and orexin A in
breast-fed, milk formula-fed and highly hydrolyzed, hypo -allergic formula-fed,
age matched infants as well as in children with iv provision of nutrients Peptides
were determined using EIA commercial kits. It was found that ghrelin and orexin
levels were significantly lower in the breast-fed children than other groups. The
postprandial concentrations of ghrelin increased in brest-fed infants and cow milk
formula-fed infants as compared to fasting values. The decrease in concentration
of ghrelin after the meal was observed only in group infants fed with hydrolyzed
milk formula diet. Now change in orexin was recorded. It was concluded that only
highly hydrolyzed diet strongly affects fasting and postprandial ghrelin and orexin
plasma concentrations. This may influence the normal growth and development
with possible negative effect on short and long-time effects on development. Also
total parenteral nutrition with the continuous stimulation and lack of fasting
modulation might be responsible for disturbed development in children fed this
way.
The findings by Author in children fed with different milk diet sound interesting
and demonstrate solid evidence with a novel aspects on ghrelin and orexin-A
contribution to the children development, though couple of issues require
clarifications before the final decision regarding this paper.
Critical comments
1. What Author mean by saying "…a total parenteral nutrition with continues
stimulation" (abstract)?
2. What means “ lack of fasting modulation” in the abstract conclusion?
3. How many Figures are included in this paper? There are two or finally three
Figures in total, in this paper? Figure descriptions indicates only two Figures,
namely Fig. 1 and Fig. 2 whereas Fig. 3 is indicated in Results (last para).
4. Both, ghrelin and orexin-A are orexigenic peptides involved in the stimulation
of appetite and hunger. Why the response on feeding with different milk diet
presented in Fig. 2 is different between both two peptides with the respect to
group I, II and III? Cleary ghrelin is suppressed while orexin-A increased? Author
should comment on that in Discussion.
5. The hydrolyzed milk diet showed the most pronounced effect on plasma
ghrelin and orexin-A levels. Which nutrients were missing in this formula as
compared to others used as the feeding for this children? Author comment on
that issue might be explanatory to the observed changes in these peptides
concentration. This need to be also discussed in the light of ghrelin-like obesity
developed by these children in the adulthood.
6. Discussion is too long and repetitive in some aspects. It might be shortened by
about 30% without the harm to that paper. Instead Authors should discussed
points raised in this review.
Level of interest: An article of importance in its field
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.