Hypoallergenicity assessment of an extensively hydrolyzed whey-protein formula in cow's milk allergic infants.

BACKGROUND: Extensively hydrolyzed formulas are recommended for the dietary management of infants with cow's milk allergy (CMA). OBJECTIVES: Hypoallergenicity, growth, and gastrointestinal (GI) tolerability of a new extensively hydrolyzed whey-protein formula (eHWF) in CMA children were assessed. METHODS: In this prospective, randomized, international, multi-center study (Trial NL3889), 34 children with confirmed CMA (74% IgE-mediated) underwent a double-blind, placebo-controlled food challenge (DBPCFC) with an eHWF developed with non-porcine enzymes, supplemented with prebiotic short-chain galacto- and long-chain fructo-oligosaccharides (0.8 g/L, ratio 9:1), arachidonic acid (0.35/100 g), and docosahexaenoic acid (0.35/100 g). If tolerant to the eHWF, children participated in a 7-day open food challenge with this eHWF. Anthropometrics and GI tolerability were assessed in an optional 16-weeks follow-up. RESULTS: Of the 34 children who started the DBPCFC with the eHWF, 25 subjects (19 boys, mean age: 61 weeks, 18 with IgE-mediated CMA) completed the DBPCFC and 7-day open challenge without major protocol deviations and tested negative at both challenges. One child experienced a late moderate eczematous allergic reaction in the optional follow-up period, indicating the need for close monitoring of subjects starting new formula. Weight and length gain followed the World Health Organization growth curves. Changes in frequency and consistency of stools upon test formula intake were transient. CONCLUSIONS: The newly developed eHWF is a suitable option in CMA treatment as all subjects tolerated the product. This result is in line with the international criteria for hypoallergenicity (American Academy of Pediatrics) that state that more than 90% of CMA children must tolerate the formula. Use of the formula is also associated with normal growth curves and GI tolerability. TRIAL REGISTRATION: Trial NL3889, https://www.trialregister.nl/trial/3889.

Ligilactobacillus salivarius PS2 Supplementation during Pregnancy and Lactation Prevents Mastitis: A Randomised Controlled Trial.

Mastitis is considered one of the main reasons for unwanted breastfeeding cessation. This study aimed to investigate the preventive effect of the probiotic strain Ligilactobacillus salivarius PS2 on the occurrence of mastitis in lactating women. In this multicountry, multicenter, randomized, double-blind, placebo-controlled trial, 328 women were assigned to the probiotic or the placebo group. The intervention started from the 35th week of pregnancy until week 12 post-partum. The primary outcome was the incidence (hazard) rate of mastitis, defined as the presence of at least two of the following symptoms: breast pain, breast erythema, breast engorgement not relieved by breastfeeding, and temperature > 38 °C. The probability of being free of mastitis during the study was higher in the probiotic than in the placebo group (p = 0.022, Kaplan-Meier log rank test) with 9 mastitis cases (6%) vs. 20 mastitis cases (14%), respectively. The hazard ratio of the incidence of mastitis between both study groups was 0.41 (0.190-0.915; p = 0.029), indicating that women in the probiotic group were 58% less likely to experience mastitis. In conclusion, supplementation of L. salivarius PS2 during late pregnancy and early lactation was safe and effective in preventing mastitis, which is one of the main barriers for continuing breastfeeding.

Fermented infant formula (with Bifidobacterium breve C50 and Streptococcus thermophilus O65) with prebiotic oligosaccharides is safe and modulates the gut microbiota towards a microbiota closer to that of breastfed infants.

BACKGROUND & AIMS: Microbiome-modulators can help positively steer early-life microbiota development but their effects on microbiome functionality and associated safety and tolerance need to be demonstrated. We investigated the microbiome impact of a new combination of bioactive compounds, produced by the food-grade microorganisms Bifidobacterium breve C50 and Streptococcus thermophilus ST065 during a fermentation process, and prebiotics in an infant formula. Tolerance and safety were also assessed. METHODS: An exploratory prospective, randomized, double-blind, controlled, multi-centre study was designed to investigate the effect of bioactive compounds and prebiotics (short-chain galacto-oligosaccharides (scGOS)/long-chain fructo-oligosaccharides (lcFOS) 9:1). Experimental formulas containing these bioactive compounds and prebiotics (FERM/scGOS/lcFOS), prebiotics (scGOS/lcFOS), or bioactive compounds (FERM), were compared to a standard cow's milk-based control formula (Control). Exclusively breastfed infants were included as a reference arm since exclusive breastfeeding is considered as the optimal feeding for infants. The study lasted six months and included visits to health care professionals at baseline, two, four and six months of age. Stool SIgA concentration was the primary study outcome parameter. RESULTS: There were 280 infants randomized over the experimental arms and 70 infants entered the breastfed-reference arm. Demographics were balanced, growth and tolerance parameters were according to expectation and adverse events were limited. At four months of age the median SIgA concentration in the FERM/scGOS/lcFOS group was significantly higher compared to the Control group (p = 0.03) and was more similar to the concentrations found in the breastfed-reference group. Bifidobacterium increased over time in all groups. The FERM/scGOS/lcFOS combination resulted in a microbiota composition and metabolic activity closer to the breastfed infants' microbiome. CONCLUSION: The FERM/scGOS/lcFOS combination showed a significant positive effect on SIgA levels. All formulas tested were associated with normal growth and were well-tolerated. Additionally, at four months of age the FERM/scGOS/lcFOS formula brought the microbiome composition and metabolic activity closer towards that of breastfed infants. CLINICAL TRIAL REGISTRY: Registration number NTR2726 (Netherlands Trial Register; www.trialregister.nl/).

Early-Life Events, Including Mode of Delivery and Type of Feeding, Siblings and Gender, Shape the Developing Gut Microbiota.

Colonization of the infant gut is believed to be critically important for a healthy growth as it influences gut maturation, metabolic, immune and brain development in early life. Understanding factors that influence this process is important, since an altered colonization has been associated with a higher risk of diseases later in life. Fecal samples were collected from 108 healthy neonates in the first half year of life. The composition and functionality of the microbiota was characterized by measuring 33 different bacterial taxa by qPCR/RT qPCR, and 8 bacterial metabolites. Information regarding gender, place and mode of birth, presence of siblings or pets; feeding pattern and antibiotic use was collected by using questionnaires. Regression analysis techniques were used to study associations between microbiota parameters and confounding factors over time. Bacterial DNA was detected in most meconium samples, suggesting bacterial exposure occurs in utero. After birth, colonization by species of Bifidobacterium, Lactobacillus and Bacteroides was influenced by mode of delivery, type of feeding and presence of siblings, with differences found at species level and over time. Interestingly, infant-type bifidobacterial species such as B. breve or B. longum subsp infantis were confirmed as early colonizers apparently independent of the factors studied here, while B. animalis subsp. lactis presence was found to be dependent solely on the type of feeding, indicating that it might not be a common infant gut inhabitant. One interesting and rather unexpected confounding factor was gender. This study contributes to our understanding of the composition of the microbiota in early life and the succession process and the evolution of the microbial community as a function of time and events occurring during the first 6 months of life. Our results provide new insights that could be taken into consideration when selecting nutritional supplementation strategies to support the developing infant gut microbiome.

The inhibitory Fc gamma IIb receptor dampens TLR4-mediated immune responses and is selectively up-regulated on dendritic cells from rheumatoid arthritis patients with quiescent disease.

Rheumatoid arthritis (RA) is a common autoimmune disease leading to profound disability and premature death. Although a role for FcgammaRs and TLRs is accepted, their precise involvement remains to be elucidated. FcgammaRIIb is an inhibitory FcR important in the maintenance of tolerance. We hypothesized that the inhibitory FcgammaRIIb inhibits TLR responses on monocyte-derived dendritic cells (DC) and serves as a counterregulatory mechanism to dampen inflammation, and we surmised that this mechanism might be defective in RA. The expression of the inhibitory FcgammaRIIb was found to be significantly higher on DCs from RA patients having low RA disease activity in the absence of treatment with antirheumatic drugs. The expression of activating FcgammaRs was similarly distributed among all RA patients and healthy controls. Intriguingly, only DCs with a high expression of FcgammaRIIb were able to inhibit TLR4-mediated secretion of proinflammatory cytokines when stimulated with immune complexes. In addition, when these DCs were coincubated with the combination of a TLR4 agonist and immune complexes, a markedly inhibited T cell proliferation was apparent, regulatory T cell development was promoted, and T cells were primed to produce high levels of IL-13 compared with stimulation of the DCs with the TLR4 agonist alone. Blocking FcgammaRIIb with specific Abs fully abrogated these effects demonstrating the full dependence on the inhibitory FcgammaRIIb in the induction of these phenomena. This TLR4-FcgammaRIIb interaction was shown to dependent on the PI3K and Akt pathway.

The functional variant (Asp299gly) of toll-like receptor 4 (TLR4) influences TLR4-mediated cytokine production in rheumatoid arthritis.

OBJECTIVE: To investigate functional consequences of the Toll-like receptor 4 (TLR4) variant (Asp299Gly) in rheumatoid arthritis (RA). METHODS: Peripheral blood mononuclear cells from 28 patients with RA carrying or not carrying the TLR4 variant were incubated with lipopolysaccharide (LPS) and heat shock protein B8 (HSPB8). Concentrations of interleukin 6 (IL-6), tumor necrosis factor-alpha(TNF-alpha), and IL-10 were determined along with TLR4 and CD14 expression. RESULTS: TLR4 expression was similar in patients carrying or not carrying the variant. In contrast, both LPS and HSPB8 resulted in significantly lower secretion of IL-6, TNF-alpha, and IL-10 in those who carried the variant, whereas the frequency of CD14+ cells was higher in these individuals. CONCLUSION: TLR4 variant clearly reduces its potency to mediate signaling. Correction for CD14+ cells is necessary in comparable experiments.

Stimulation of TLR2 and TLR4 differentially skews the balance of T cells in a mouse model of arthritis.

TLRs may contribute to the progression of rheumatoid arthritis through recognition of microbial or host-derived ligands found in arthritic joints. Here, we show that TLR2 and TLR4, but not TLR9, are involved in the pathogenesis of autoimmune arthritis and play distinct roles in the regulation of T cells and cytokines. We investigated the involvement of TLR2, TLR4, and TLR9 in the progression of arthritis using IL-1 receptor antagonist-knockout (IL1rn-/-) mice, which spontaneously develop an autoimmune T cell-mediated arthritis. Spontaneous onset of arthritis was dependent on TLR activation by microbial flora, as germ-free mice did not develop arthritis. Clinical and histopathological evaluation of IL1rn-/-Tlr2-/- mice revealed more severe arthritis, characterized by reduced suppressive function of Tregs and substantially increased IFN-gamma production by T cells. IL1rn-/-Tlr4-/- mice were, in contrast, protected against severe arthritis and had markedly lower numbers of Th17 cells and a reduced capacity to produce IL-17. A lack of Tlr9 did not affect the progression of arthritis. While any therapeutic intervention targeting TLR2 still seems complicated, the strict position of TLR4 upstream of a number of pathogenic cytokines including IL-17 provides an interesting potential therapeutic target for rheumatoid arthritis.

Inhibition of Toll-like receptor 4 breaks the inflammatory loop in autoimmune destructive arthritis.

OBJECTIVE: Degeneration of extracellular matrix of cartilage leads to the production of molecules capable of activating the immune system via Toll-like receptor 4 (TLR-4). The objective of this study was to investigate the involvement of TLR-4 activation in the development and progression of autoimmune destructive arthritis. METHODS: A naturally occurring TLR-4 antagonist, highly purified lipopolysaccharide (LPS) from Bartonella quintana, was first characterized using mouse macrophages and human dendritic cells (DCs). Mice with collagen-induced arthritis (CIA) and mice with spontaneous arthritis caused by interleukin-1 receptor antagonist (IL-1Ra) gene deficiency were treated with TLR-4 antagonist. The clinical score for joint inflammation, histologic characteristics of arthritis, and local expression of IL-1 in joints were evaluated after treatment. RESULTS: The TLR-4 antagonist inhibited DC maturation induced by Escherichia coli LPS and cytokine production induced by both exogenous and endogenous TLR-4 ligands, while having no effect on these parameters by itself. Treatment of CIA using TLR-4 antagonist substantially suppressed both clinical and histologic characteristics of arthritis without influencing the adaptive anti-type II collagen immunity crucial for this model. Treatment with TLR-4 antagonist strongly reduced IL-1beta expression in articular chondrocytes and synovial tissue. Furthermore, such treatment inhibited IL-1-mediated autoimmune arthritis in IL-1Ra(-/-) mice and protected the mice against cartilage and bone pathology. CONCLUSION: In the present study, we demonstrate for the first time that inhibition of TLR-4 suppresses the severity of experimental arthritis and results in lower IL-1 expression in arthritic joints. Our data suggest that TLR-4 might be a novel target in the treatment of rheumatoid arthritis.

MIF production by dendritic cells is differentially regulated by Toll-like receptors and increased during rheumatoid arthritis.

Macrophage migration inhibitory factor (MIF) is clearly associated with rheumatoid arthritis (RA) disease severity. However, the regulation of MIF during the course of RA has not been subjected to similar scientific scrutiny. The aim of our study was to investigate the role of various Toll-like receptors (TLRs) and inflammatory mediators on MIF production by dendritic cells (DCs) in healthy controls and RA patients. DCs were cultured from 12 healthy donors and 12 RA patients. Triggering via TLR mediated pathways was achieved using various TLR specific ligands alone or in combination: Pam3Cys for TLR2, LPS and recombinant extra domain A containing fibronectin for TLR4 and Poly(I:C) and R848 for TLR3 and TLR7, respectively. In addition, iDCs from healthy controls were incubated with various cytokines, RANKL and CD40L for 48 h. MIF levels were measured using an ELISA assay. Stimulation of DCs by TLR4 ligands resulted in higher MIF production compared to immature DCs from healthy controls (p<0.002) and RA patients (p<0.002). DCs from RA patients produced higher MIF levels than healthy controls both at the immature stage (p<0.04) as well after full maturation via TLR2 (p<0.04) and TLR4 (p<0.001) triggering. Incubation with TLR3 and TLR7 ligands resulted in a significantly decreased secretion of MIF in RA patients and controls. Simultaneous incubation of TLR4 with either TLR3 or TLR7 ligands resulted in a decrease of MIF secretion when compared to TLR4 stimulation alone. The secretion of MIF increased when DCs were stimulated with TNF-alpha, RANKL and CD40L. The secretion of MIF by dendritic cells is differentially regulated by TLRs. In addition, TNF-alpha, RANKL, and CD40L augment MIF production by DCs and thus play a potential role in the amplification of the inflammatory loop in RA.

Novel insights in the regulation of CCL18 secretion by monocytes and dendritic cells via cytokines, toll-like receptors and rheumatoid synovial fluid.

BACKGROUND: The T cell attracting chemokine CCL18 is produced by antigen presenting cells and a role for CCL18 has been suggested in the pathogenesis of a variety of diseases. Rheumatoid arthritis (RA) is one of these conditions, in which abundant CCL18 production is present. Although Th2 cytokines and IL-10 are known to have an effect on CCL18 production, there are several gaps in our knowledge regarding the exact regulation of CCL18 secretion, both in general and in RA. In this study we provide new insights in the regulation of CCL18 secretion by monocytes and dendritic cells. RESULTS: In contrast to a large panel of pro-inflammatory stimuli (IL-1beta, TNF-alpha, IL-10, IL-13, IL-15, IL-17, IL-18, IFN-gamma), T cell mimicking molecules (RANKL, CD40L) or TLR driven maturation, the anti-inflammatory IL-10 strongly stimulated DC to secrete CCL18. On freshly isolated monocytes, CCL18 secretion was induced by IL-4 and IL-13, in strong synergy with IL-10. This synergistic effect could already be observed after only 24 hours, indicating that not only macrophages and dendritic cells, but also monocytes secrete CCL18 under these stimulatory conditions. A high CCL18 expression was detected in RA synovial tissue and incubation of monocytes with synovial fluid from RA patients clearly enhanced the effects of IL-4, IL-13 and IL-10. Surprisingly, the effect of synovial fluid was not driven by IL-10 of IL-13, suggesting the presence of another CCL18 inducing factor in synovial fluid. CONCLUSION: In summary, IL-10 synergistically induces CCL18 secretion in combination with IL-4 of IL-13 on monocytes and monocyte derived cells. The effects of IL-14, IL-13 and IL-10 are strongly enhanced by synovial fluid. This synergy may contribute to the high CCL18 expression in RA.

Identification of small heat shock protein B8 (HSP22) as a novel TLR4 ligand and potential involvement in the pathogenesis of rheumatoid arthritis.

Dendritic cells (DCs) are specialized APCs that can be activated upon pathogen recognition as well as recognition of endogenous ligands, which are released during inflammation and cell stress. The recognition of exogenous and endogenous ligands depends on TLRs, which are abundantly expressed in synovial tissue from rheumatoid arthritis (RA) patients. Furthermore TLR ligands are found to be present in RA serum and synovial fluid and are significantly increased, compared with serum and synovial fluid from healthy volunteers and patients with systemic sclerosis and systemic lupus erythematosus. Identification of novel endogenous TLR ligands might contribute to the elucidation of the role of TLRs in RA and other autoimmune diseases. In this study, we investigated whether five members of the small heat shock protein (HSP) family were involved in TLR4-mediated DC activation and whether these small HSPs were present in RA synovial tissue. In vitro, monocyte-derived DCs were stimulated with recombinant alphaA crystallin, alphaB crystallin, HSP20, HSPB8, and HSP27. Using flow cytometry and multiplex cytokine assays, we showed that both alphaA crystallin and HSPB8 were able to activate DCs and that this activation was TLR4 dependent. Furthermore, Western blot and immunohistochemistry showed that HSPB8 was abundantly expressed in synovial tissue from patients with RA. With these experiments, we identified sHSP alphaA crystallin and HSPB8 as two new endogenous TLR4 ligands from which HSPB8 is abundantly expressed in RA synovial tissue. These findings suggest a role for HSPB8 during the inflammatory process in autoimmune diseases such as RA.

Expression of toll-like receptors 2 and 4 in rheumatoid synovial tissue and regulation by proinflammatory cytokines interleukin-12 and interleukin-18 via interferon-gamma.

OBJECTIVE: To study the expression of Toll-like receptor 2 (TLR-2) and TLR-4 and its association with proinflammatory cytokines in synovial tissue from patients with rheumatoid arthritis (RA), osteoarthritis (OA), and healthy individuals. METHODS: Synovial tissue specimens from 29 RA patients were stained for TLR-2, TLR-4, and proinflammatory cytokines (interleukin-1beta [IL-1beta], IL-12, IL-17, IL-18, and tumor necrosis factor alpha [TNFalpha]). The expression of TLR-2, TLR-4, and cytokines as well as the degree of inflammation in synovial tissue were compared between patients with RA, patients with OA (n = 5), and healthy individuals (n = 3). Peripheral blood mononuclear cells (PBMCs) were incubated with IL-12 and IL-18, and TLR expression was assessed using fluorescence-activated cell sorter analysis. Production of TNFalpha and IL-6 was measured using Luminex bead array technology. RESULTS: In RA synovial tissue, the expression of TLR-2 was slightly higher than that of TLR-4. Interestingly, both TLR-2 and TLR-4 were expressed at higher levels in moderately inflamed synovium, as compared with synovial tissue with no or severe inflammation. TLR expression in both the lining and the sublining was associated with the presence of IL-12 and IL-18, but no other cytokines, in the lining. The expression of both TLRs was low in synovial tissue from OA patients and healthy donors. Stimulation of PBMCs with IL-12 and IL-18 resulted in increased expression of both TLR-2 and TLR-4; this could be blocked with anti-interferon-gamma (anti-IFNgamma) antibodies, suggesting a role for IFNgamma. Lipopolysaccharide- or lipoteichoic acid-mediated triggering of PBMCs incubated with IL-12/IL-18 or IFNgamma led to an increased production of both TNFalpha and IL-6, indicating the functionality of TLR-2 and TLR-4. CONCLUSION: TLR-2 and TLR-4 are expressed in synovial tissue of patients with clinically active disease and are associated with the levels of both IL-12 and IL-18. The synergistic effect of IL-12 and IL-18 on T cell IFNgamma production seems to regulate expression of TLR-2 and TLR-4 in the synovial tissue of RA patients.