Research of relations between allergy and change of levels of somatostatin and motilin in breast milk

Objective To study the relations between allergy and change of somatostatin (SST) and motilin (MTL) in breast milk, so as to provide reference for further research of pathomechanism of food allergy in infants. Methods From January 2011 to December 2015, a total of 23 cases of infants who were diagnosed as allergic gastroenteritis because of pure breast feeding were included into research group. All the patients were hospitalized in Department of Gastrointestinal in West China Second University Hospital, Sichuan University. Diagnostic criteria for allergy of breast milk were repeated alimentary symptoms which would release when stop breast feeding, and rechallenge test of breast milk induced the same symptoms. Inclusion criteria for allergic gastroenteritis infants in research group included: younger than 6 months of exclusive breastfeeding infants who visited medical clinic frequently as digestive disorders, and exclusion criteria were alimentary malformation, hereditary diseases and gastrointestinal infection of specific pathogen. During the same time and in the same hospital, a total of 23 cases of normal infants with pure breast feeding were collected as control group. Samples of their breast milk and stools were collected in two groups. Levels of SST and MTL in breast milk and stools were detected by radioimmunoassay (RIA). There were no significant differences between two groups among gender ratios, age and weight, breast-feeding practices, etc. (P>0.05). The study protocol was approved by the Ethical Review Board of Investigation in Human Being of West China Second University Hospital, Sichuan University. Informed consent was obtained from the parents of each participating infant. Results Level of SST in breast milk was (236.7±28.9) pg/mg in research group, and (412.6±36.7) pg/mg in control group, level of SST in research group was much lower than that in control group, and there was significant difference between two groups (t=2.821, P=0.012). Level of MTL in breast milk was (159.4±36.7) pg/mg in research group, and (216.8±59.7) pg/mg in control group, level of MTL in research group was much lower than that in control group, and there was significant difference between two groups (t=2.517, P=0.026). Level of SST in stool sample was (32.6±8.9) pg/mg in research group, and (56.2±12.7) pg/mg in control group, level of SST in research group was much lower than that in control group, and there was significant difference between two groups (t=2.506, P=0.029). Level of MTL in stool sample was (12.3±3.7) pg/mg in research group, and (21.6±4.7) pg/mg in control group, level of MTL in research group was much lower than that in control group, and there was significant difference between two groups (t=2.468, P=0.031). Conclusions Gastrointestinal peptides are also important bioactive components in breast milk. Deficiency of SST in breast milk may decrease immunotolerance of food, and contribute to allergy. Deficiency of MTL in breast milk may helps to induce food intolerance and functional dyspepsia. Key words: Breast feeding; Diarrhea, infantile; Allergy and immunology; Somatostatin; Motilin