CD14 polymorphisms in mother and infant, soluble CD14 in breast milk and atopy development in the infant (KOALA Study)

Microbiota Composition of Breast Milk from Women of Different Ethnicity from the Manawatu-Wanganui Region of New Zealand

Human breastmilk components, the microbiota and immune modulatory proteins have vital roles in infant gut and immune development. In a population of breastfeeding women (n = 78) of different ethnicities (Asian, Māori and Pacific Island, New Zealand European) and their infants living in the Manawatu–Wanganui region of New Zealand, we examined the microbiota and immune modulatory proteins in the breast milk, and the fecal microbiota of mothers and infants. Breast milk and fecal samples were collected over a one-week period during the six to eight weeks postpartum. Breast milk microbiota differed between the ethnic groups. However, these differences had no influence on the infant’s gut microbiota composition. Based on the body mass index (BMI) classifications, the mother’s breast milk and fecal microbiota compositions were similar between normal, overweight and obese individuals, and their infant’s fecal microbiota composition also did not differ. The relative abundance of bacteria belonging to the Bacteroidetes phylum was higher in feces of infants born through vaginal delivery. However, the bacterial abundance of this phylum in the mother’s breast milk or feces was similar between women who delivered vaginally or by cesarean section. Several immune modulatory proteins including cytokines, growth factors, and immunoglobulin differed between the BMI and ethnicity groups. Transforming growth factor beta 1 and 2 (TGFβ1, TGFβ2) were present in higher concentrations in the milk from overweight mothers compared to those of normal weight. The TGFβ1 and soluble cluster of differentiation 14 (sCD14) concentrations were significantly higher in the breast milk from Māori and Pacific Island women compared with women from Asian and NZ European ethnicities. This study explores the relationship between ethnicity, body mass index, mode of baby delivery and the microbiota of infants and their mothers and their potential impact on infant health.

Maternal weight and excessive weight gain during pregnancy modify the immunomodulatory potential of breast milk

INTRODUCTION

Breast milk is an optimal source of nutrition for infants. It contains bioactive components including bacteria that support the microbial colonization and immune system development of the infant. The determinants of human milk composition remain poorly understood, although maternal nutritional and immunological status as well as lifestyle and dietary habits seem to have an impact.

METHODS

The subjects selected were women from a prospective follow-up study categorized by BMI. Milk samples were taken after delivery and at 1 and 6 mo later for analysis of composition in regard to transforming growth factor (TGF)-β2, soluble CD14 (sCD14), cytokines, and microbiota.

RESULTS

TGF-β2 and sCD14 levels in the breast milk of overweight mothers tended to be lower than the levels in that of normal-weight mothers. Also, higher levels of Staphylococcus group bacteria and lower levels of Bifidobacterium group bacteria were detected in overweight mothers as compared with normal-weight ones. The prevalence of Akkermansia muciniphila-type bacteria was also higher in overweight mothers, and the numbers of these bacteria were related to the interleukin (IL)-6 concentration in the colostrum, which was in turn related to lower counts of Bifidobacterium group bacteria in the breast milk of overweight women.

DISCUSSION

Complex interactions of cytokines and microbiota in breast milk guide the microbiological, immunological, and metabolic programming of infant health. Our data may indicate the presence of an additional mechanism that may explain the heightened risk of obesity for infants of overweight and excessive weight gain mothers.

Microbial ecology and host-microbiota interactions during early life stages

The role of human microbiota has been redefined during recent years and its physiological role is now much more important than earlier understood. Intestinal microbial colonization is essential for the maturation of immune system and for the developmental regulation of the intestinal physiology. Alterations in this process of colonization have been shown to predispose and increase the risk to disease later in life. The first contact of neonates with microbes is provided by the maternal microbiota. Moreover, mode of delivery, type of infant feeding and other perinatal factors can influence the establishment of the infant microbiota. Taken into consideration all the available information it could be concluded that the exposure to the adequate microbes early in gestation and neonatal period seems to have a relevant role in health. Maternal microbial environment affects maternal and fetal immune physiology and, of relevance, this interaction with microbes at the fetal-maternal interface could be modulated by specific microbes administered to the pregnant mother. Indeed, probiotic interventions aiming to reduce the risk of immune-mediated diseases may appear effective during early life.

Protocadherin-1 polymorphisms are associated with eczema in two Dutch birth cohorts

BACKGROUND

  Eczema and asthma share a common genetic background and show linkage to chromosome 5q31-33. Protocadherin-1 (PCDH1) is located in this region and was identified as a susceptibility gene for bronchial hyper-responsiveness (BHR), a hallmark of asthma. PCDH1 encodes an adhesion molecule, expressed in airway and skin epithelium. We determined whether PCDH1 polymorphisms, previously associated with asthma or BHR, also associated with questionnaire and UK Working Party (UKWP) defined eczema.

METHODS

  Four PCDH1 polymorphisms were genotyped in two Dutch birth cohorts, PIAMA (n = 967) and KOALA Birth Cohort Study (n = 1560). Association with eczema was determined by chi-square tests and generalized estimating equations (GEE).

RESULTS

  Insertion deletion IVS3-116 was associated with development of UKWP eczema in PIAMA [age 4, OR = 1.90 (1.14-3.18)] and borderline with questionnaire-reported eczema in PIAMA [GEE, OR = 1.33 (0.98-1.81)]. Furthermore, IVS3-116 was associated with questionnaire-reported eczema in KOALA [age 1, OR = 1.44 (1.00-2.07)]. Pooled analysis of questionnaire-reported eczema of both cohorts resulted in a significant association of IVS3-116 with eczema [OR = 1.26 (1.01-1.58)]. Rs3822357 (A-allele) associated with protection for eczema in PIAMA only [questionnaires, OR = 0.19 (0.06-0.63)].

CONCLUSION

  PCDH1 gene variant IVS3-116 associates with eczema in two independent birth cohorts. Combined with previous observations, this indicates a shared genetic susceptibility to BHR, asthma and eczema.