The skin microbiome in the first year of life and its association with atopic dermatitis.

BACKGROUND: Early-life microbial colonization of the skin may modulate the immune system and impact the development of atopic dermatitis (AD) and allergic diseases later in life. To address this question, we assessed the association between the skin microbiome and AD, skin barrier integrity and allergic diseases in the first year of life. We further explored the evolution of the skin microbiome with age and its possible determinants, including delivery mode. METHODS: Skin microbiome was sampled from the lateral upper arm on the first day of life, and at 3, 6, and 12 months of age. Bacterial communities were assessed by 16S rRNA gene amplicon sequencing in 346 infants from the PreventADALL population-based birth cohort study, representing 970 samples. Clinical investigations included skin examination and skin barrier function measured as trans-epidermal water loss (TEWL) at the site and time of microbiome sampling at 3, 6, and 12 months. Parental background information was recorded in electronic questionnaires, and delivery mode (including vaginal delivery (VD), VD in water, elective caesarean section (CS) and emergency CS) was obtained from maternal hospital charts. RESULTS: Strong temporal variations in skin bacterial community composition were found in the first year of life, with distinct patterns associated with different ages. Confirming our hypothesis, skin bacterial community composition in the first year of life was associated with skin barrier integrity and later onsets of AD. Delivery mode had a strong impact on the microbiome composition at birth, with each mode leading to distinct patterns of colonization. Other possible determinants of the skin microbiome were identified, including environmental and parental factors as well as breastfeeding. CONCLUSION: Skin microbiome composition during infancy is defined by age, transiently influenced by delivery mode as well as environmental, parental factors and breastfeeding. The microbiome is also associated with skin barrier integrity and the onset of AD.

Fatty acid-binding protein3 expression in BeWo cells, a human placental choriocarcinoma cell line.

Cellular uptake of long chain fatty acids in human placental trophoblasts is thought to be mediated by several membrane- and cytoplasmic fatty acid-binding proteins (FABP). FABP3 was shown to be involved in long chain polyunsaturated fatty acids (LCPUFA) uptake in human trophoblastic choriocarcinoma cells, BeWo as the uptake of arachidonic acid,20:4n-6 (ARA) was decreased in FABP3-knockdown BeWo cells. However, the regulation of expression of FABP3 in these cells is not yet well known. The aim of the present study was to examine the FABP3 expression by LCPUFAs, insulin and LXR agonists in BeWo cells. Among all these fatty acids tested, only ARA dose-dependently stimulated the expression of FABP3 protein in these cells after 24h incubation while other fatty acids had no such effect. In addition, LXR agonist and insulin dose-dependently increased FABP3 protein expression in these cells after 24h incubation. Insulin-stimulated FABP3 protein expression was accompanied with an increased arachidonic acid uptake. Differentiated BeWo cells had lesser expression of FABP3 protein than in the undifferentiated cells as the cellular differentiation state was measured by hCG production. In preeclamptic placental tissue, lowered expression of FABP3 protein was observed compared with those in normal pregnancy. All these data indicate that FABP3 may in be part involved in ARA uptake in these cells and its expression may be regulated by ARA, insulin, LXR and the state of cellular differentiation.