Soluble CD14, α-and β-defensins in breast milk: association with the emergence of allergy in a high-risk population

Human β-Defensin 2 and Its Postulated Role in Modulation of the Immune Response

Studies described so far suggest that human β-defensin 2 is an important protein of innate immune response which provides protection for the human organism against invading pathogens of bacterial, viral, fungal, as well as parasitical origin. Its pivotal role in enhancing immunity was proved in infants. It may also be considered a marker of inflammation. Its therapeutic administration has been suggested for maintenance of the balance of systemic homeostasis based on the appropriate composition of the microbiota. It has been suggested that it may be an important therapeutic tool for modulating the response of the immune system in many inflammatory diseases, offering new treatment modalities. For this reason, its properties and role in the human body discussed in this review should be studied in more detail.

Levels of Total Antioxidant Capacity, sCD14, and TGF-β2 in Breast Milk Plasma of HIV-Infected and HIV-Uninfected Lactating Women

Introduction: Breast milk provides nourishment for infants and nonnutritive bioactive factors, which possess key protective and developmental benefits essential in shaping the infant immune system. However, the impact of human immunodeficiency virus (HIV) and universal antiretroviral therapy (ART) on breast milk nutritional composition and immunity status is not well documented. Objective: The study aimed to compare breast milk immune factors; total antioxidant capacity (TAC), soluble cluster of differentiation 14 (sCD14), and transcription growth factor-beta 2 (TGF-β2) levels between HIV-infected and HIV-uninfected lactating mothers and determine the association between breast milk parameters with HIV disease progression and duration of ART. Methods: Breast milk sCD14, TAC, and TGF-β2 were quantified using enzyme-linked immunosorbent assays and spectrophotometric techniques in 57 HIV-infected breast feeding mothers on option B⁺ therapy for prevention of vertical transmission of HIV and 57 HIV-uninfected mothers at 6 weeks postpartum. The plasma HIV viral load was measured on enrollment and demographic data were recorded. Results: Mean breast milk plasma TAC levels were significantly lower in HIV-infected mothers (1,250.5 ± 280.4 μmolTE/L) compared to the HIV-uninfected participants (1,915.4 ± 326 μmolTE/L; p < 0.001). Soluble CD14 levels in HIV-infected mothers were significantly higher (7,059.3 ± 1,604.7 ng/mL) compared to the HIV-uninfected group (5,670.7 ± 1,268.3 pg/mL; p < 0.001). Similarly, TGF-β2 concentration was also significantly elevated in the HIV-infected mothers (1,426.1 ± 695.4 pg/mL) compared to the HIV-uninfected counterparts (709.2 ± 196.8 pg/mL; p < 0.001). A positive correlation was observed between breast milk plasma sCD14 concentration and the plasma viral load (r = 0.576, p < 0.001), while a significant negative correlation was observed with the duration of ART (r = -0.285, p = 0.032). TAC and TGF-β2 concentrations were inversely correlated with plasma viral load levels. Conclusion: HIV-infected mothers are at risk of oxidative stress. Nutritional intervention with antioxidant rich foods is recommended for this vulnerable group during breastfeeding.

Probiotic Supplementation and Human Milk Cytokine Profiles in Japanese Women: A Retrospective Study from an Open-Label Pilot Study

The benefits of probiotic supplementation to lactating mothers on human milk cytokines are inconclusive. Thus, we performed a comprehensive open-label pilot trial analysis of 27 human milk cytokines in lactating women with allergies (one to three months postpartum) to determine the effect of supplementation with a mixture of new probiotic strains. Participants voluntarily joined the probiotic (n = 41) or no supplementation control (n = 19) groups. The probiotic group took three probiotic tablets (Lactobacillus casei LC5, Bifidobacterium longum BG7, and Bacillus coagulans SANK70258) daily for one to three months postpartum. Milk samples were collected at one, two, and three months postpartum, and cytokine levels were measured using multiplex assays. The effects were analyzed using multivariate regression models. Eleven cytokines showed a positive rate of over 50% in the milk samples throughout testing in both groups. The positive rates of IL-1 receptor antagonist and IL-7 changed significantly with lactation progression in logistic regression models after adjusting for time and supplementation, whereas rates of other cytokines showed no significant differences. The lactational change patterns of IL-10 concentrations differed significantly between the two groups. A short-term supplementation of probiotics affects human milk cytokine levels in lactating women with a possible placebo effect still existing. Future placebo-controlled studies are needed to support these results, based on the estimated sample sizes in this study.

Perinatal and Early-Life Nutrition, Epigenetics, and Allergy

Epidemiological studies have shown a dramatic increase in the incidence and the prevalence of allergic diseases over the last several decades. Environmental triggers including risk factors (e.g., pollution), the loss of rural living conditions (e.g., farming conditions), and nutritional status (e.g., maternal, breastfeeding) are considered major contributors to this increase. The influences of these environmental factors are thought to be mediated by epigenetic mechanisms which are heritable, reversible, and biologically relevant biochemical modifications of the chromatin carrying the genetic information without changing the nucleotide sequence of the genome. An important feature characterizing epigenetically-mediated processes is the existence of a time frame where the induced effects are the strongest and therefore most crucial. This period between conception, pregnancy, and the first years of life (e.g., first 1000 days) is considered the optimal time for environmental factors, such as nutrition, to exert their beneficial epigenetic effects. In the current review, we discussed the impact of the exposure to bacteria, viruses, parasites, fungal components, microbiome metabolites, and specific nutritional components (e.g., polyunsaturated fatty acids (PUFA), vitamins, plant- and animal-derived microRNAs, breast milk) on the epigenetic patterns related to allergic manifestations. We gave insight into the epigenetic signature of bioactive milk components and the effects of specific nutrition on neonatal T cell development. Several lines of evidence suggest that atypical metabolic reprogramming induced by extrinsic factors such as allergens, viruses, pollutants, diet, or microbiome might drive cellular metabolic dysfunctions and defective immune responses in allergic disease. Therefore, we described the current knowledge on the relationship between immunometabolism and allergy mediated by epigenetic mechanisms. The knowledge as presented will give insight into epigenetic changes and the potential of maternal and post-natal nutrition on the development of allergic disease.

Protective Effect of Breastfeeding on the Adverse Health Effects Induced by Air Pollution: Current Evidence and Possible Mechanisms

Air pollution is a major social, economic, and health problem around the world. Children are particularly susceptible to the negative effects of air pollution due to their immaturity and excessive growth and development. The aims of this narrative review were to: (1) summarize evidence about the protective effects of breastfeeding on the adverse health effects of air pollution exposure, (2) define and describe the potential mechanisms underlying the protective effects of breastfeeding, and (3) examine the potential effects of air pollution on breastmilk composition and lactation. A literature search was conducted using electronic databases. Existing evidence suggests that breastfeeding has a protective effect on adverse outcomes of indoor and outdoor air pollution exposure in respiratory (infections, lung function, asthma symptoms) and immune (allergic, nervous and cardiovascular) systems, as well as under-five mortality in both developing and developed countries. However, some studies reported no protective effect of breastfeeding or even negative effects of breastfeeding for under-five mortality. Several possible mechanisms of the breastfeeding protective effect were proposed, including the beneficial influence of breastfeeding on immune, respiratory, and nervous systems, which are related to the immunomodulatory, anti-inflammatory, anti-oxidant, and neuroprotective properties of breastmilk. Breastmilk components responsible for its protective effect against air pollutants exposure may be long chain polyunsaturated fatty acids (LC PUFA), antioxidant vitamins, carotenoids, flavonoids, immunoglobins, and cytokines, some of which have concentrations that are diet-dependent. However, maternal exposure to air pollution is related to increased breastmilk concentrations of pollutants (e.g., Polycyclic aromatic hydrocarbons (PAHs) or heavy metals in particulate matter (PM)). Nonetheless, environmental studies have confirmed that breastmilk's protective effects outweigh its potential health risk to the infant. Mothers should be encouraged and supported to breastfeed their infants due to its unique health benefits, as well as its limited ecological footprint, which is associated with decreased waste production and the emission of pollutants.

Soluble CD14 in Breast Milk and Its Relation to Atopic Manifestations in Early Infancy

Soluble CD14 (sCD14) is one of the immunomodulatory factors in breast milk (BM). Although it may be involved in the prevention of atopic symptoms and sensitization to both food and inhalant allergens, conflicting evidence exists concerning its protective effects. In this study, we investigated the relationship between sCD14 in colostrum and 1-month BM, and the development of atopic dermatitis (AD) and sensitization to food and aeroallergens at 9 months of age in infants who were exclusively or almost exclusively breastfed up to 4 months of age. BM samples were collected from lactating mothers who participated in a 2 × 2 factorial, randomized, nontreatment controlled trial study set in Tokyo, which looked at the efficacy of emollients and synbiotics in preventing AD and food allergy in children during the first year of life. A total of 258 colostrum samples and 269 1-month BM samples were analyzed. We found that one-month BM sCD14 levels in the AD group were significantly lower than in the non-AD group. Levels of sCD14 in 1-month BM were not related to allergen sensitization in the overall analysis, but egg white sensitization correlated inversely with 1-month BM sCD14 in infants without AD. The results suggest that sCD14 in BM may be involved in atopic manifestations in early infancy.

Reviewing the evidence on breast milk composition and immunological outcomes

A large number of biologically active components have been found in human milk (HM), and in both human and animal models, studies have provided some evidence suggesting that HM composition can be altered by maternal exposures, subsequently influencing health outcomes for the breastfed child. Evidence varies from the research studies on whether breastfeeding protects the offspring from noncommunicable diseases, including those associated with immunological dysfunction. It has been hypothesized that the conflicting evidence results from HM composition variations, which contain many immune active molecules, oligosaccharides, lactoferrin, and lysozyme in differing concentrations, along with a diverse microbiome. Determining the components that influence infant health outcomes in terms of both short- and long-term sequelae is complicated by a lack of understanding of the environmental factors that modify HM constituents and thereby offspring outcomes. Variations in HM immune and microbial composition (and the differing infantile responses) may in part explain the controversies that are evidenced in studies that aim to evaluate the prevalence of allergy by prolonged and exclusive breastfeeding. HM is a "mixture" of immune active factors, oligosaccharides, and microbes, which all may influence early immunological outcomes. This comprehensive review provides an in-depth overview of existing evidence on the studied relationships between maternal exposures, HM composition, vaccine responses, and immunological outcomes.

Association of maternal allergy with human milk soluble CD14 and fatty acids, and early childhood atopic dermatitis

BACKGROUND

This study aimed to investigate whether maternal allergy is associated with soluble CD14 (sCD14) and fatty acid composition in different stages of lactation and the onset of atopic dermatitis (AD) in early childhood.

METHODS

In total, 443 mother-child groups (445 children) were enrolled in the Prediction of Allergies in Taiwanese Children birth cohort study. Colostrum and mature milk at 2 months postpartum (2-month HM) were collected from lactating mothers. Information regarding parental allergy histories and physician-diagnosed atopic diseases was obtained using age-specific questionnaires (0-2 years). We compared sCD14 levels and the composition of 30 fatty acids in the colostrum and 2-month HM, respectively, between allergic and non-allergic mothers and between children with and without AD by the age of 2 years.

RESULTS

In total, 185 (41.8%) mothers presented with allergies, and 154 (34.6%) children had physician-diagnosed AD by the age of 2 years. Both in the colostrum and 2-month HM of 289 lactating mothers, sCD14 levels were significantly lower in allergic mothers whose children presented with AD compared with children who did not (P = 0.015 and 0.044, respectively). Among the children with AD who were born to non-allergic mothers, sCD14 levels were lower. However, the result was not statistically significant (P = 0.376 and 0.264, respectively). Our data revealed the lack of associations between fatty acid composition and AD (P > 0.05).

CONCLUSION

Decreased sCD14 levels in the colostrum and 2-month HM were associated with AD at 2 years of age, particularly among children born to mothers with allergies.

Immunologically Active Components in Human Milk and Development of Atopic Disease, With Emphasis on Food Allergy, in the Pediatric Population

Breast-feeding is currently recommended to prevent the development of allergic diseases; however, data are conflicting and mechanisms are unclear. The immunomodulatory composition of human milk is poorly characterized and varies between mothers. We and others have shown that high levels of human milk IgA and certain cytokines and human milk oligosaccharides are associated with protection against food allergy in the infant, but it is unclear whether they are responsible for or simply biomarkers of the vertical transfer of protection. Because human milk has pre- and probiotic properties, the anti-allergy protection afforded by human milk may be due to its control on the developing gut microbiome. In mice, murine milk IgA supports gut homeostasis and shapes the microbiota, which in turn diversifies the intestinal IgA repertoire that reciprocally promotes the diversity of gut microbiome; these mechanisms are poorly understood in humans. In addition, several human milk bioactives are immunostimulatory, which may in part provide protection against allergic diseases. The regulation of immunologically active components in human milk is incompletely understood, although accumulating evidence suggests that IgA and cytokines in human milk reflect maternal exposures. This review summarizes the current literature on human milk components that have been associated with protection against food allergy and related allergic disorders in early childhood and discusses the work relating to regulation of these levels in human milk and possible mechanisms of action.

Pre- and probiotics for allergy prevention: time to revisit recommendations?

Reduced intensity and diversity of microbial exposure is considered a major factor driving abnormal postnatal immune maturation and increasing allergy prevalence, particularly in more affluent regions. Quantitatively, the largest important source of early immune-microbial interaction, the gut microbiota, is of particular interest in this context, with variations in composition and diversity in the first months of life associated with subsequent allergy development. Attempting to restore the health consequences of the 'dysbiotic drift' in modern society, interventions modulating gut microbiota for allergy prevention have been evaluated in several randomized placebo-controlled trials. In this review, we provide an overview of these trials and discuss recommendations from international expert bodies regarding prebiotic, probiotic and synbiotic interventions. Recent guidelines from the World Allergy Organization recommend the use of probiotics for the primary prevention of eczema in pregnant and breastfeeding mothers of infants at high risk for developing allergy and in high-risk infants. It is however stressed that these recommendations are conditional, based on very low-quality evidence and great heterogeneity between studies, which also impedes specific and practical advice to consumers on the most effective regimens. We discuss how the choice of probiotic strains, timing and duration of administration can critically influence the outcome due to different effects on immune modulation and gut microbiota composition. Furthermore, we propose strategies to potentially improve allergy-preventive effects and enable future evidence-based implementation.

Human Milk and Allergic Diseases: An Unsolved Puzzle

There is conflicting evidence on the protective role of breastfeeding in relation to the development of allergic sensitisation and allergic disease. Studies vary in methodology and definition of outcomes, which lead to considerable heterogeneity. Human milk composition varies both within and between individuals, which may partially explain conflicting data. It is known that human milk composition is very complex and contains variable levels of immune active molecules, oligosaccharides, metabolites, vitamins and other nutrients and microbial content. Existing evidence suggests that modulation of human breast milk composition has potential for preventing allergic diseases in early life. In this review, we discuss associations between breastfeeding/human milk composition and allergy development.

Human beta-defensins 2 and -3 cointernalize with human immunodeficiency virus via heparan sulfate proteoglycans and reduce infectivity of intracellular virions in tonsil epithelial cells

We previously showed that expression of the anti-HIV innate proteins human beta-defensin 2 (hBD2) and hBD3 in adult oral epithelial cells reduces HIV transepithelial transmission by inactivation of virus. However, fetal/infant oral epithelia lack beta-defensin expression, leading to transmission of HIV. The mechanisms of hBD2- and hBD3-mediated HIV inactivation in adult oral epithelial cells are poorly understood. Here we found that heparan sulfate proteoglycans (HSPGs) on the apical surfaces of epithelial cells facilitate simultaneous binding of hBDs and HIV gp120 to the cell surface. HSPG-facilitated binding of hBDs and HIV gp120 to the cell surface did not affect viral attachment. HBD2 or -3 cointernalized with virions in endosomes, formed oligomers, and reduced infectivity of HIV. The anti-HIV effect of combining hBD2 and hBD3 was substantially higher than that of the individual peptides. These findings advance our understanding of the mechanisms of anti-HIV resistance in adult oral epithelium.