Sustainable diets with plant-based proteins require considerations for prevention of proteolytic fermentation.

The human diet requires a more plant-based approach due to the exhaustive effects animal-based foods have on the environment. However, plant-based proteins generally miss a few or have a lower variety in essential amino acids and are more difficult to digest. Subsequently they might be prone to fermentation by the microbiome in the proximal colon. Proteolytic fermentation can induce microbial-metabolites with beneficial and negative health effects. We review current insight into how balances in saccharolytic and proteolytic fermentation can be maintained when the diet consists predominantly of plant-based proteins. Some proteolytic fermentation metabolites may negatively impact balances in gut microbiota composition in the large intestine and influence immunity. However, proteolytic fermentation can potentially be prevented in the proximal colon toward more saccharolytic fermentation through the addition of non-digestible carbohydrates in the diet. Knowledge on this combination of plant-based proteins and non-digestible carbohydrates on colonic- and general health is limited. Current data suggest that transitioning toward a more plant-based protein diet should be accompanied with a consumption of increased quantities and more complex structures of carbohydrates or by application of technological strategies to enhances digestibility. This can reduce or prevent proteolytic fermentation which might consequently improve human health.

Gastrointestinal barrier function, immunity, and neurocognition: The role of human milk oligosaccharide (hMO) supplementation in infant formula.

Breastmilk is seen as the gold standard for infant nutrition as it provides nutrients and compounds that stimulate gut barrier, immune, and brain development to the infant. However, there are many instances where it is not possible for an infant to be fed with breastmilk, especially for the full 6 months recommended by the World Health Organization. In such instances, infant formula is seen as the next best approach. However, infant formulas do not contain human milk oligosaccharides (hMOs), which are uniquely present in human milk as the third most abundant solid component. hMOs have been linked to many health benefits, such as the development of the gut microbiome, the immune system, the intestinal barrier, and a healthy brain. This paper reviews the effects of specific hMOs applied in infant formula on the intestinal barrier, including the not-often-recognized intestinal alkaline phosphatase system that prevents inflammation. Additionally, impact on immunity and the current proof for effects in neurocognitive function and the corresponding mechanisms are discussed. Recent studies suggest that hMOs can alter gut microbiota, modulate intestinal immune barrier function, and promote neurocognitive function. The hMOs 2'-fucosyllactose and lacto-N-neotetraose have been found to have positive effects on the development of infants and have been deemed safe for use in formula. However, their use has been limited due to their cost and complexity of synthesis. Thus, although many benefits have been described, complex hMOs and combinations of hMOs with other oligosaccharides are the best approach to stimulate gut barrier, immune, and brain development and for the prevention of disease.

Structure-function relationship and impact on the gut-immune barrier function of non-digestible carbohydrates and human milk oligosaccharides applicable for infant formula.

Human milk oligosaccharides (hMOs) in mothers' milk play a crucial role in guiding the colonization of microbiota and gut-immune barrier development in infants. Non-digestible carbohydrates (NDCs) such as synthetic single hMOs, galacto-oligosaccharides (GOS), inulin-type fructans and pectin oligomers have been added to infant formula to substitute some hMOs' functions. HMOs and NDCs can modulate the gut-immune barrier, which is a multiple-layered functional unit consisting of microbiota, a mucus layer, gut epithelium, and the immune system. There is increasing evidence that the structures of the complex polysaccharides may influence their efficacy in modulating the gut-immune barrier. This review focuses on the role of different structures of individual hMOs and commonly applied NDCs in infant formulas in (i) direct regulation of the gut-immune barrier in a microbiota-independent manner and in (ii) modulation of microbiota composition and microbial metabolites of these polysaccharides in a microbiota-dependent manner. Both have been shown to be essential for guiding the development of an adequate immune barrier, but the effects are very dependent on the structural features of hMO or NDC. This knowledge might lead to tailored infant formulas for specific target groups.

TLR2 and TLR4 activity in monocytes and macrophages after exposure to amoxicillin, ciprofloxacin, doxycycline and erythromycin.

BACKGROUND: Antibiotics are used to treat bacterial infections but also impact immunity. This is usually attributed to antibiotic-induced dysbiosis of the microbiota, but antibiotics may have a direct effect on immune cells and immunity-associated receptors, such as Toll-like receptors (TLRs). OBJECTIVES: To investigate whether antibiotics alter TLR2/1, TLR2/6 and TLR4 activity in immune cells. METHODS: We evaluated the effects of amoxicillin, ciprofloxacin, doxycycline and erythromycin on TLR2/1-, TLR2/6- and TLR4-induced NF-κB activation in THP1-XBlue™-MD2-CD14 cells. Furthermore, we studied TNF-α and IL-6 levels in THP-1-derived macrophages after exposure to these antibiotics and TLR ligands. RESULTS: Amoxicillin had no effect on any of the TLRs studied. However, ciprofloxacin reduced TLR2/1, TLR2/6 and TLR4 activity in THP1-XBlue™-MD2-CD14 cells and decreased TLR2/1-induced TNF-α and IL-6 in macrophages. Doxycycline reduced TLR2/6 and TLR4 activity in THP1-XBlue™-MD2-CD14 cells and TNF-α and IL-6 levels in response to TLR2/6 stimulation in macrophages. Erythromycin decreased TLR2/1 and TLR4 activity in THP1-XBlue™-MD2-CD14 cells without changes in TNF-α and IL-6 levels in macrophages. In addition, ciprofloxacin decreased the expression of TLR2 mRNA. CONCLUSIONS: These results suggest that some antibiotics may attenuate TLR-dependent monocyte/macrophage responses and likely reduce bacterial clearance. The latter is particularly important in infections with AMR bacteria, where misprescribed antibiotics not only fail in control of AMR infections but might also weaken host defence mechanisms by limiting innate immune responses. Our data suggest that efforts should be made to prevent the deterioration of the immune response during and after antibiotic treatment.

Opportunities and challenges of polyphenols and polysaccharides for type 1 diabetes intervention.

Type 1 diabetes (T1D) is an autoimmune disorder characterized by the destruction of insulin-producing pancreatic ß cell. It contributes to high mortality, frequent diabetic complications, poor quality of life in patients and also puts a significant economic burden on health care systems. Therefore, the development of new therapeutic strategies is urgently needed. Recently, certain dietary compounds with potential applications in food industry, particularly polyphenols and polysaccharides, have gained increasing attention with their prominent anti-diabetic effects on T1D by modulating ß cell function, the gut microbiota and/or the immune system. In this review, we critically discuss the recent findings of several dietary polyphenols and polysaccharides with the potential to protect against T1D and the underlying anti-diabetic mechanisms. More importantly, we highlight the current trends, major issues, and future directions of industrial production of polyphenols- and polysaccharides-based functional foods for preventing or delaying T1D.

The Giardial Arginine Deiminase Participates in Giardia-Host Immunomodulation in a Structure-Dependent Fashion via Toll-like Receptors.

Beyond the problem in public health that protist-generated diseases represent, understanding the variety of mechanisms used by these parasites to interact with the human immune system is of biological and medical relevance. Giardia lamblia is an early divergent eukaryotic microorganism showing remarkable pathogenic strategies for evading the immune system of vertebrates. Among various multifunctional proteins in Giardia, arginine deiminase is considered an enzyme that plays multiple regulatory roles during the life cycle of this parasite. One of its most important roles is the crosstalk between the parasite and host. Such a molecular "chat" is mediated in human cells by membrane receptors called Toll-like receptors (TLRs). Here, we studied the importance of the 3D structure of giardial arginine deiminase (GlADI) to immunomodulate the human immune response through TLRs. We demonstrated the direct effect of GlADI on human TLR signaling. We predicted its mode of interaction with TLRs two and four by using the AlphaFold-predicted structure of GlADI and molecular docking. Furthermore, we showed that the immunomodulatory capacity of this virulent factor of Giardia depends on the maintenance of its 3D structure. Finally, we also showed the influence of this enzyme to exert specific responses on infant-like dendritic cells.

Disease managing capacities and mechanisms of host effects of lactic acid bacteria.

Consumption of lactic acid bacteria (LAB) has been suggested to confer health-promoting effects on the host. However, effects of LABs have been reported to be species- and strain-specific and the mechanisms involved are subjects of discussion. Here, the possible mechanisms by which LABs induce antipathogenic, gut barrier enhancing and immune modulating effects in consumers are reviewed. Specific strains for which it has been proven that health is improved by these mechanisms are discussed. However, most strains probably act via several or combinations of mechanisms depending on which effector molecules they express. Current insight is that these effector molecules are either present on the cell wall of LAB or are excreted. These molecules are reviewed as well as the ligand binding receptors in the host. Also postbiotics are discussed. Finally, we provide an overview of the efficacy of LABs in combating infections caused by Helicobacter pylori, Salmonella, Escherichia coli, Streptococcus pneumoniae, and influenza virus, in controlling gut inflammatory diseases, in managing allergic disorders, and in alleviating cancer.

More than sugar in the milk: human milk oligosaccharides as essential bioactive molecules in breast milk and current insight in beneficial effects.

Human milk is the gold standard for newborn infants. Breast milk not only provides nutrients, it also contains bioactive components that guide the development of the infant's intestinal immune system, which can have a lifelong effect. The bioactive molecules in breast milk regulate microbiota development, immune maturation and gut barrier function. Human milk oligosaccharides (hMOs) are the most abundant bioactive molecules in human milk and have multiple beneficial functions such as support of growth of beneficial bacteria, anti-pathogenic effects, immune modulating effects, and stimulation of intestine barrier functions. Here we critically review the current insight into the benefits of bioactive molecules in mother milk that contribute to neonatal development and focus on current knowledge of hMO-functions on microbiota and the gastrointestinal immune barrier. hMOs produced via genetically engineered microorganisms are now applied in infant formulas to mimic the nutritional composition of breast milk as closely as possible, and their prospects and scientific challenges are discussed in depth.

Necrostatin-1 Supplementation to Islet Tissue Culture Enhances the In-Vitro Development and Graft Function of Young Porcine Islets.

Pre-weaned porcine islets (PPIs) represent an unlimited source for islet transplantation but are functionally immature. We previously showed that necrostatin-1 (Nec-1) immediately after islet isolation enhanced the in vitro development of PPIs. Here, we examined the impact of Nec-1 on the in vivo function of PPIs after transplantation in diabetic mice. PPIs were isolated from pancreata of 8-15-day-old, pre-weaned pigs and cultured in media alone, or supplemented with Nec-1 (100 µM) on day 0 or on day 3 of culture (n = 5 for each group). On day 7, islet recovery, viability, oxygen consumption rate, insulin content, cellular composition, insulin secretion capacity, and transplant outcomes were evaluated. While islet viability and oxygen consumption rate remained high throughout 7-day tissue culture, Nec-1 supplementation on day 3 significantly improved islet recovery, insulin content, endocrine composition, GLUT2 expression, differentiation potential, proliferation capacity of endocrine cells, and insulin secretion. Adding Nec-1 on day 3 of tissue culture enhanced the islet recovery, proportion of delta cells, beta-cell differentiation and proliferation, and stimulation index. In vivo, this leads to shorter times to normoglycemia, better glycemic control, and higher circulating insulin. Our findings identify the novel time-dependent effects of Nec-1 supplementation on porcine islet quantity and quality prior to transplantation.

Multilevel Approach for the Treatment of Giardiasis by Targeting Arginine Deiminase.

Giardiasis represents a latent problem in public health due to the exceptionally pathogenic strategies of the parasite Giardia lamblia for evading the human immune system. Strains resistant to first-line drugs are also a challenge. Therefore, new antigiardial therapies are urgently needed. Here, we tested giardial arginine deiminase (GlADI) as a target against giardiasis. GlADI belongs to an essential pathway in Giardia for the synthesis of ATP, which is absent in humans. In silico docking with six thiol-reactive compounds was performed; four of which are approved drugs for humans. Recombinant GlADI was used in enzyme inhibition assays, and computational in silico predictions and spectroscopic studies were applied to follow the enzyme's structural disturbance and identify possible effective drugs. Inhibition by modification of cysteines was corroborated using Ellman's method. The efficacy of these drugs on parasite viability was assayed on Giardia trophozoites, along with the inhibition of the endogenous GlADI. The most potent drug against GlADI was assayed on Giardia encystment. The tested drugs inhibited the recombinant GlADI by modifying its cysteines and, potentially, by altering its 3D structure. Only rabeprazole and omeprazole decreased trophozoite survival by inhibiting endogenous GlADI, while rabeprazole also decreased the Giardia encystment rate. These findings demonstrate the potential of GlADI as a target against giardiasis.

Human Milk Oligosaccharides Mediate the Crosstalk Between Intestinal Epithelial Caco-2 Cells and Lactobacillus PlantarumWCFS1in an In Vitro Model with Intestinal Peristaltic Shear Force.

BACKGROUND: The intestinal epithelial cells, food molecules, and gut microbiota are continuously exposed to intestinal peristaltic shear force. Shear force may impact the crosstalk of human milk oligosaccharides (hMOs) with commensal bacteria and intestinal epithelial cells. OBJECTIVES: We investigated how hMOs combined with intestinal peristaltic shear force impact intestinal epithelial cells and crosstalk with a commensal bacterium. METHODS: We applied the Ibidi system to mimic intestinal peristaltic shear force. Caco-2 cells were exposed to a shear force (5 dynes/cm2) for 3 d, and then stimulated with the hMOs, 2'-fucosyllactose (2'-FL), 3-FL, and lacto-N-triose II (LNT2). In separate experiments, Lactobacillus plantarumWCFS1 adhesion to Caco-2 cells was studied with the same hMOs and shear force. Effects were tested on gene expression of glycocalyx-related molecules (glypican 1 [GPC1], hyaluronan synthase 1 [HAS1], HAS2, HAS3, exostosin glycosyltransferase 1 [EXT1], EXT2), defensin ß-1 (DEFB1), and tight junction (tight junction protein 1 [TJP1], claudin 3 [CLDN3]) in Caco-2 cells. Protein expression of tight junctions was also quantified. RESULTS: Shear force dramatically decreased gene expression of the main enzymes for making glycosaminoglycan side chains (HAS3 by 43.3% and EXT1 by 68.7%) (P <0.01), but did not affect GPC1 which is the gene responsible for the synthesis of glypican 1 which is a major protein backbone of glycocalyx. Expression of DEFB1, TJP1, and CLDN3 genes was decreased 60.0-94.9% by shear force (P <0.001). The presence of L. plantarumWCFS1 increased GPC1, HAS2, HAS3, and ZO-1 expression by 1.78- to 3.34-fold (P <0.05). Under shear force, all hMOs significantly stimulated DEFB1 and ZO-1, whereas only 3-FL and LNT2 enhanced L. plantarumWCFS1 adhesion by 1.85- to 1.90-fold (P <0.01). CONCLUSIONS: 3-FL and LNT2 support the crosstalk between the commensal bacterium L. plantarumWCFS1 and Caco-2 intestinal epithelial cells, and shear force can increase the modulating effects of hMOs.

Necrostatin-1 supplementation enhances young porcine islet maturation and in vitro function.

BACKGROUND: Necroptosis has been demonstrated to be a primary mechanism of islet cell death. This study evaluated whether the supplementation of necrostatin-1 (Nec-1), a potent inhibitor of necroptosis, to islet culture media could improve the recovery, maturation, and function of pre-weaned porcine islets (PPIs). METHODS: PPIs were isolated from pre-weaned Yorkshire piglets (8-15 days old) and either cultured in control islet culture media (n = 6) or supplemented with Nec-1 (100 µM, n = 5). On days 3 and 7 of culture, islets were assessed for recovery, insulin content, viability, cellular composition, GLUT2 expression in beta cells, differentiation of pancreatic endocrine progenitor cells, function, and oxygen consumption rate. RESULTS: Nec-1 supplementation induced a 2-fold increase in the insulin content of PPIs on day 7 of culture. When compared to untreated islets, Nec-1 treatment doubled the beta- and alpha-cell composition and accelerated the development of delta cells. Additionally, beta cells of Nec-1-treated islets had a significant upregulation in GLUT2 expression. The enhanced development of major endocrine cells and GLUT2 expression after Nec-1 treatment subsequently led to a significant increase in the amount of insulin secreted in response to in vitro glucose challenge. Islet recovery, viability, and oxygen consumption rate were unaffected by Nec-1. CONCLUSION: This study underlines the importance of necroptosis in islet cell death after isolation and demonstrates the novel effects of Nec-1 to increase islet insulin content, enhance pancreatic endocrine cell development, facilitate GLUT2 upregulation in beta cells, and augment insulin secretion. Nec-1 supplementation to culture media significantly improves islet quality prior to xenotransplantation.

Acetate and Butyrate Improve ß-cell Metabolism and Mitochondrial Respiration under Oxidative Stress.

Islet dysfunction mediated by oxidative and mitochondrial stress contributes to the development of type 1 and 2 diabetes. Acetate and butyrate, produced by gut microbiota via fermentation, have been shown to protect against oxidative and mitochondrial stress in many cell types, but their effect on pancreatic ß-cell metabolism has not been studied. Here, human islets and the mouse insulinoma cell line MIN6 were pre-incubated with 1, 2, and 4 mM of acetate or butyrate with and without exposure to the apoptosis inducer and metabolic stressor streptozotocin (STZ). Both short-chain fatty acids (SCFAs) enhanced the viability of islets and ß-cells, but the beneficial effects were more pronounced in the presence of STZ. Both SCFAs prevented STZ-induced cell apoptosis, viability reduction, mitochondrial dysfunction, and the overproduction of reactive oxygen species (ROS) and nitric oxide (NO) at a concentration of 1 mM but not at higher concentrations. These rescue effects of SCFAs were accompanied by preventing reduction of the mitochondrial fusion genes MFN, MFN2, and OPA1. In addition, elevation of the fission genes DRP1 and FIS1 during STZ exposure was prevented. Acetate showed more efficiency in enhancing metabolism and inhibiting ROS, while butyrate had less effect but was stronger in inhibiting the SCFA receptor GPR41 and NO generation. Our data suggest that SCFAs play an essential role in supporting ß-cell metabolism and promoting survival under stressful conditions. It therewith provides a novel mechanism by which enhanced dietary fiber intake contributes to the reduction of Western diseases such as diabetes.

Non-digestible carbohydrates in infant formula as substitution for human milk oligosaccharide functions: Effects on microbiota and gut maturation.

Human milk (HM) is the golden standard for nutrition of newborn infants. Human milk oligosaccharides (HMOs) are abundantly present in HM and exert multiple beneficial functions, such as support of colonization of the gut microbiota, reduction of pathogenic infections and support of immune development. HMO-composition is during lactation continuously adapted by the mother to accommodate the needs of the neonate. Unfortunately, for many valid reasons not all neonates can be fed with HM and are either totally or partly fed with cow-milk derived infant formulas, which do not contain HMOs. These cow-milk formulas are supplemented with non-digestible carbohydrates (NDCs) that have functional effects similar to that of some HMOs, since production of synthetic HMOs is challenging and still very expensive. However, NDCs cannot substitute all HMO functions. More efficacious NDCs may be developed and customized for specific groups of neonates such as pre-matures and allergy prone infants. Here current knowledge of HMO functions in the neonate in view of possible replacement of HMOs by NDCs in infant formulas is reviewed. Furthermore, methods to expedite identification of suitable NDCs and structure/function relationships are reviewed as in vivo studies in babies are impossible.

Relationship Between Oligosaccharides and Glycoconjugates Content in Human Milk and the Development of the Gut Barrier.

The intestinal immune barrier is considered to be the gatekeeper of the human body and rapidly develops directly after birth. Many pre- and postnatal factors influence the development of the gut-barrier, which is composed of the microbiota, the mucus, the epithelial layer and the mucosal immune system. Even minor disturbances during barrier development can have consequences for health far into adulthood. Here we critically discuss the current knowledge on which pre- and postnatal factors influence development, maturation, and maintenance of the gut immune barrier. Human milk has a unique composition and is the gold standard for adequate development of the intestinal immune barrier. Not only the influence of human milk oligosaccharides (HMOs) but also that of glycoproteins (HMGPs) is reviewed. We discuss the influence of maternal genetic factors, such as the secretor and Lewis phenotypes on breast milk fucosylation and sialylation of HMOs and HMGPs. This diversity in HMOs and HMPGs influences microbiota composition and also the development of the immune barrier. Cow milk-derived infant formula is often being used as an alternative for human breast milk. The consequences of this for proper development of the intestinal immune barrier and, in particular, the differences in the type of oligosaccharides and glycosylation patterns (sialic and fucose composition) between cow and human milk are critically discussed. Current and prospective strategies to promote proper gut-immune maturation are proposed. These might include more personalized infant formulas when breast milk is not an option.

Extracellular matrix molecules and their potential contribution to the function of transplanted pancreatic islets.

Extracellular matrix (ECM) molecules are responsible for structural and biochemical support, as well as for regulation of molecular signalling and tissue repair in many organ structures, including the pancreas. In pancreatic islets, collagen type IV and VI, and laminins are the most abundant molecules, but other ECM molecules are also present. The ECM interacts with specific combinations of integrin α/ß heterodimers on islet cells and guides many cellular processes. More specifically, some ECM molecules are involved in beta cell survival, function and insulin production, while others can fine tune the susceptibility of islet cells to cytokines. Further, some ECM induce release of growth factors to facilitate tissue repair. During enzymatic isolation of islets for transplantation, the ECM is damaged, impacting islet function. However, restoration of the ECM in human islets (for example by adding ECM to the interior of immunoprotective capsules) has been shown to enhance islet function. Here, we provide current insight into the role of ECM molecules in islet function and discuss the clinical potential of ECM manipulation to enhance pancreatic islet function and survival.

Polymer scaffolds for pancreatic islet transplantation - Progress and challenges.

Pancreatic-islet transplantation is a safe and noninvasive therapy for type 1 diabetes. However, the currently applied site for transplantation, ie, the liver, is not the optimal site for islet survival. Because the human body has shortcomings in providing an optimal site, artificial transplantation sites have been proposed. Such an artificial site could consist of a polymeric scaffold that mimics the pancreatic microenvironment and supports islet function. Recently, remarkable progress has been made in the technology of engineering scaffolds. The polymer-islet interactions, the site of implantation, and scaffold prevascularization are critical factors for success or failure of the scaffolds. This article critically reviews these factors while also discussing translation of experimental studies to human application as well as the steps required to create a clinically applicable prevascularized, retrievable scaffold for implantation of insulin-producing cells for treatment of type 1 diabetes mellitus.

Human umbilical vein endothelium-derived exosomes play a role in foetoplacental endothelial dysfunction in gestational diabetes mellitus.

Gestational diabetes mellitus (GDM) characterizes by foetoplacental endothelial dysfunction. Human umbilical vein endothelial cells (HUVECs) from women with GDM show increased L-arginine transport via the human cationic amino acid transporter 1 (hCAT-1). Moreover, expression of endothelial nitric oxide synthase (eNOS) and nitric oxide synthesis are increased. Exosomes are increased in maternal plasma from GDM. We evaluated the role of foetoplacental endothelial exosomes on endothelial dysfunction in GDM. Exosomes were isolated from HUVECs from normal (ExN) and GDM (ExGDM) pregnancies. HUVECs were exposed (8h) to ExN or ExGDM and used for wound recovery assay (up to 8h), L-arginine transport, hCAT-1 and eNOS expression and activity, reactive oxygen species (ROS) generation, and 44 and 42kDa mitogen activated protein kinases (p44/42mapk) and protein kinase B/Akt (Akt) activation. Wound recovery was slower in GDM compared with normal pregnancies and was recovered by ExN. However, ExGDM delayed wound recovery in cells from normal pregnancies. GDM-increased L-arginine transport, hCAT-1 and eNOS expression and activity, and p44/42mapk activation were blocked by ExN, but ExGDM increased these parameters and ROS generation, and reduced eNOS phosphorylation at threonine495 in cells from normal pregnancies. Inhibition of p44/42mapk, but not Akt reversed GDM-increased L-arginine uptake. In conclusion foetoplacental endothelial-released exosomes play a role in the maintenance of a GDM phenotype in HUVECs. It is suggested that ExN and ExGDM cargo are different with differential effects in cells from normal or GDM pregnancies. This phenomenon could contribute to the understanding of mechanisms behind foetoplacental endothelial dysfunction in GDM pregnancies.

Therapeutic Strategies for Modulating the Extracellular Matrix to Improve Pancreatic Islet Function and Survival After Transplantation.

PURPOSES OF REVIEW: Extracellular matrix (ECM) components modulate the interaction between pancreatic islet cells. During the islet isolation prior to transplantation as treatment for type 1 diabetes, the ECM is disrupted impacting functional graft survival. Recently, strategies for restoring ECM have shown to improve transplantation outcomes. This review discusses the current therapeutic strategies to modulate ECM components to improve islet engraftment. RECENT FINDINGS: Approaches applied are seeding islets in ECM of decellularized organs, supplementation of specific ECM components in polymeric scaffolds or immunoisolating capsules, and stimulating islet ECM production with specific growth factors or ECM-producing cells. These strategies have shown success in improving functional islet survival. However, the same experiments show that caution should be taken as some ECM components may negatively impact islet function and engraftment. ECM restoration resulted in improved transplantation outcomes, but careful selection of beneficial ECM components and strategies is warranted.

Aged mice display altered numbers and phenotype of basophils, and bone marrow-derived basophil activation, with a limited role for aging-associated microbiota.

BACKGROUND: The influence of age on basophils is poorly understood, as well as the effect of aging-associated microbiota on basophils. Therefore, we studied the influence of aging and aging-associated microbiota on basophil frequency and phenotype, and differentiation from basophil precursors. RESULTS: Basophils became more abundant in bone marrow (BM) and spleens of 19-month-old mice compared with 4-month-old mice. Aged basophils tended to express less CD200R3 and more CD123, both in BM and spleen. Differences in microbiota composition with aging were confirmed by 16S sequencing. Microbiota transfers from young and old mice to germ-free recipients revealed that CD11b tended to be lowered on splenic basophils by aging-associated microbiota. Furthermore, abundance of Alistipes, Oscillibacter, Bacteroidetes RC9 gut group, and S24-7 family positively correlated and CD123 expression, whereas Akkermansia abundance negatively correlated with basophils numbers.Subsequently, we purified FcεRIα+CD11c-CD117- BM-derived basophils and found that those from aged mice expressed lower levels of CD11b upon stimulation. Higher frequencies of IL-4+ basophils were generated from basophil precursors of aged mice, which could be reproduced in basophils derived from germ-free recipients of aging-associated microbiota. CONCLUSIONS: Collectively, these results show the influence of aging on basophils. Furthermore, this study shows that aging-associated microbiota altered activation of BM-derived basophils in a similar fashion as observed in BM-derived basophils from aged mice.