Репозиторий Университета

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. A growing number of studies are focusing on the associations between human milk (HM) immunological composition and allergic diseases. This scoping review aims to identify statistical methods applied in the field and highlight pitfalls and unmet needs. A comprehensive literature search in MEDLINE and Embase retrieved 13,607 unique records. Following title/abstract screening, 29 studies met the selection criteria and were included in this review. We found that definitions of colostrum and mature milk varied across the studies. A total of 17 out of 29 (59%) studies collected samples longitudinally, but only 12% of these used serial (longitudinal) analyses. Multivariable analysis was used in 45% of the studies, but statistical approaches to modelling varied largely across the studies. Types of variables included as potential confounding factors differed considerably between models. Discrimination analysis was absent from all studies and only a single study reported classification measures. Outcomes of this scoping review highlight lack of standardization, both in data collection and handling, which remains one of the main challenges in the field. Improved standardization could be obtained by a consensus group of researchers and clinicians that could recommend appropriate methods to be applied in future prospective studies, as well as already existing datasets.

© 2019 John Wiley  &  Sons Ltd Background: Human milk (HM) transforming growth factor beta (TGF-β) is critical for inflammation regulation and oral tolerance promotion. Previous reports suggested that variations in HM TGF-β levels are associated with allergic outcomes. Objective: We undertook a systematic review (PROSPERO 2017 CRD42017069920) to reassess the evidence on the relationships between HM TGF-β and allergic outcomes in children. Methods: Electronic bibliographic databases (MEDLINE, EMBASE and Cochrane Library) were systematically searched. Two independent reviewers screened reference lists, extracted the data and assessed risk of bias using the National Institute for Clinical Excellence methodological checklist. Results: A total of 21 studies were identified. Sixteen studies assessed relationships between HM TGF-β and risk of eczema; 14, allergic sensitization; nine, wheezing/asthma; six, food allergy; three, allergic rhinitis/conjunctivitis. Five cohorts (5/18, 28%) reported a protective effect of TGF-β1, while 3 (3/10, 30%) suggested increased risk of allergic outcomes development and 1 (1/10, 10%), a protective effect of TGF-β2 on eczema. Meta-analysis was not possible due to significant heterogeneity in methodology, age of outcome assessment and differing statistical approaches. 71% (15/21) of studies carried a high risk of bias. Conclusion and clinical relevance: In contrast with previous findings, we did not find strong evidence of associations between HM TGF-β and allergic outcomes. Differences in studies' methodology and outcomes do not allow unconditional rejection or acceptance of the hypothesis that HM TGF-β influences the risk of allergy development. Future studies on diverse populations employing standardized methods, accurate phenotyping of outcomes and evaluation of the effect of TGF-β in combination with other HM immune markers, microbiome and oligosaccharides are required.

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. Colostrum is produced in the first days postpartum. It is a known source of immune mediators for a newborn within the first week of life. Although it is still unclear if colostrum composition varies between populations, recent data suggest differences. Hepatocyte growth factor (HGF); transforming growth factor-β (TGF-β) 1, 2, and 3; and immunoglobulin A (IgA) are key immunological components of colostrum that stimulate neonatal gastrointestinal and immune system development. We aimed to investigate the differences in the concentration between immune markers in the colostrum of mothers living in Burundi and Italy, and to identify the factors associated with differences. In this cross-sectional birth cohort study, a total of 99 colostrum samples from Burundian (n = 23) and Italian (n = 76) women were collected at 0 to 6 days postpartum. A clinical chemistry analyser was used for IgA quantification and electro-chemiluminescence, for HGF and TGFβ1-3 assessment. A univariate analysis and multivariate linear regression model were used for statistical testing. The concentrations of TGF-β2 (p = 0.01) and IgA (p < 0.01) were significantly higher in the colostrum from the women residing in Burundi than in Italy, both in a univariate analysis and upon the adjustment for confounding factors. A similar trend is seen for HGF, reaching statistical significance upon a multivariate analysis. We found a moderate to strong positive correlation between the TGF-β isoforms and IgA concentration in both countries (p < 0.01), with stronger concentration in the colostrum from Burundi. The results of this study are in support of previous data, suggesting that concentration of the immune active molecules is higher in the human milk of women residing in developing countries. However, with a small sample size, caution must be applied, as the findings require further confirmation. Future work should also be focused on other factors (e.g., lipid and microbial composition), as well as the investigation into colostrum and between populations comparison, adjusting for potential confounders.

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. Human milk provides essential substrates for the optimal growth and development of a breastfed infant. Besides providing nutrients to the infant, human milk also contains metabolites which form an intricate system between maternal lifestyle, such as the mother’s diet and the gut microbiome, and infant outcomes. This study investigates the variation of these human milk metabolites from five different countries. Human milk samples (n = 109) were collected one month postpartum from Australia, Japan, the USA, Norway, and South Africa and were analyzed by nuclear magnetic resonance. The partial least squares discriminant analysis (PLS-DA) showed separation between either maternal countries of origin or ethnicities. Variation between countries in concentration of metabolites, such as 2-oxoglutarate, creatine, and glutamine, in human milk, between countries, could provide insights into problems, such as mastitis and/or impaired functions of the mammary glands. Several important markers of milk production, such as lactose, betaine, creatine, glutamate, and glutamine, showed good correlation between each metabolite. This work highlights the importance of milk metabolites with respect to maternal lifestyle and the environment, and also provides the framework for future breastfeeding and microbiome studies in a global context.