A Pilot Study of Human Milk to Reduce Intestinal Inflammation After Bone Marrow Transplant

Geographic Influence on Subgingival Microbiota in Health and Periodontitis: A Multinational Shotgun Metagenomic Study

AIMS

To assess the differences in the taxonomical and functional profile of the subgingival microbiota isolated from healthy subjects (HS) and patients with periodontitis (PP) from four different countries.

METHODS

In this study, 80 subgingival samples from HS and PP from four different countries (Belgium, Chile, Peru, and Spain) were analyzed using shotgun metagenomic sequencing.

RESULTS

The results indicated significant variation in α-diversity between HS and PP, segregated by country, with PP from Peru clearly standing out from the rest. In terms of composition, β-diversity was explained more by the country of origin (6.8%) than by the diagnosis (4.1%). In addition, more than 75 different taxa, 63 of which were identified at the species level, showed significantly different relative abundances when comparing the country of origin, diagnosis, and both variables combined. Moreover, 85 metabolic pathways showed significantly different relative abundances between HS and PP, with species commonly associated with periodontitis, such as Porphyromonas gingivalis and Tannerella forsythia, strongly contributing to the reinforcement of periodontitis-associated pathways. On the other hand, differences in functional profiles based on the country of origin were almost nonexistent, suggesting that variability in taxonomic profiles does not have a direct impact on healthy or periodontitis-associated functional profiles.

CONCLUSION

These findings suggest that microbial analysis should take into account the geographic origin of samples in order to provide a more accurate description of the subgingival microbiota. Moreover, they lay the groundwork for larger and more comprehensive studies that might analyze this phenomenon in the future.

The Microbiome and Pediatric Transplantation

The microbial communities that inhabit our bodies have been increasingly linked to host physiology and pathophysiology. This microbiome, through its role in colonization resistance, influences the risk of infections after transplantation, including those caused by multidrug-resistant organisms. In addition, through both direct interactions with the host immune system and via the production of metabolites that impact local and systemic immunity, the microbiome plays an important role in the establishment of immune tolerance after transplantation, and conversely, in the development of graft-versus-host disease and graft rejection. This review offers a comprehensive overview of the evidence for the role of the microbiome in hematopoietic cell and solid organ transplant complications, drivers of microbiome shift during transplantation, and the potential of microbiome-based therapies to improve pediatric transplantation outcomes.

Transcriptome analysis in acute gastrointestinal graft-versus host disease reveals a unique signature in children and shared biology with pediatric inflammatory bowel disease

We performed transcriptomic analyses on freshly frozen (n=21) and paraffin-embedded (n=35) gastrointestinal (GI) biopsies from children with and without acute acute GI graft-versus-host disease (GvHD) to study differential gene expressions. We identified 164 significant genes, 141 upregulated and 23 downregulated, in acute GvHD from freshy frozen biopsies. CHI3L1 was the top differentially expressed gene in acute GvHD, involved in macrophage recruitment and bacterial adhesion. Mitochondrial genes were among the top downregulated genes. Immune deconvolution identified a macrophage cellular signature. Weighted gene co-expression network analysis showed enrichment of genes in the ERK1/2 cascade. Transcriptome data from 206 ulcerative colitis (UC) patients were included to uncover genes and pathways shared between GvHD and UC. Comparison with the UC transcriptome showed both shared and distinct pathways. Both UC and GvHD transcriptomes shared an innate antimicrobial signature and FCγ1RA/CD64 was upregulated in both acute GvHD (log-fold increase 1.7, P=0.001) and UC. Upregulation of the ERK1/2 cascade pathway was specific to GvHD. We performed additional experiments to confirm transcriptomics. Firstly, we examined phosphorylation of ERK (pERK) by immunohistochemistry on GI biopsies (acute GvHD n=10, no GvHD n=10). pERK staining was increased in acute GvHD biopsies compared to biopsies without acute GvHD (P=0.001). Secondly, plasma CD64, measured by enzyme-linked immunsorbant assay (n=85) was elevated in acute GI GvHD (P<0.001) compared with those without and was elevated in GVHD compared with inflammatory bowel disease (n=47) (P<0.001), confirming the upregulated expression seen in the transcriptome.

Implementing an exclusive human milk diet for preterm infants: real-world experience in diverse NICUs

BACKGROUND

Human milk-based human milk fortifier (HMB-HMF) makes it possible to provide an exclusive human milk diet (EHMD) to very low birth weight (VLBW) infants in neonatal intensive care units (NICUs). Before the introduction of HMB-HMF in 2006, NICUs relied on bovine milk-based human milk fortifiers (BMB-HMFs) when mother's own milk (MOM) or pasteurized donor human milk (PDHM) could not provide adequate nutrition. Despite evidence supporting the clinical benefits of an EHMD (such as reducing the frequency of morbidities), barriers prevent its widespread adoption, including limited health economics and outcomes data, cost concerns, and lack of standardized feeding guidelines.

METHODS

Nine experts from seven institutions gathered for a virtual roundtable discussion in October 2020 to discuss the benefits and challenges to implementing an EHMD program in the NICU environment. Each center provided a review of the process of starting their program and also presented data on various neonatal and financial metrics associated with the program. Data gathered were either from their own Vermont Oxford Network outcomes or an institutional clinical database. As each center utilizes their EHMD program in slightly different populations and over different time periods, data presented was center-specific. After all presentations, the experts discussed issues within the field of neonatology that need to be addressed with regards to the utilization of an EHMD in the NICU population.

RESULTS

Implementation of an EHMD program faces many barriers, no matter the NICU size, patient population or geographic location. Successful implementation requires a team approach (including finance and IT support) with a NICU champion. Having pre-specified target populations as well as data tracking is also helpful. Real-world experiences of NICUs with established EHMD programs show reductions in comorbidities, regardless of the institution's size or level of care. EHMD programs also proved to be cost effective. For the NICUs that had necrotizing enterocolitis (NEC) data available, EHMD programs resulted in either a decrease or change in total (medical + surgical) NEC rate and reductions in surgical NEC. Institutions that provided cost and complications data all reported a substantial cost avoidance after EHMD implementation, ranging between $515,113 and $3,369,515 annually per institution.

CONCLUSIONS

The data provided support the initiation of EHMD programs in NICUs for very preterm infants, but there are still methodologic issues to be addressed so that guidelines can be created and all NICUs, regardless of size, can provide standardized care that benefits VLBW infants.

Human Milk Oligosaccharides: Potential Applications in COVID-19

Coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) has become a global health crisis with more than four million deaths worldwide. A substantial number of COVID-19 survivors continue suffering from long-COVID syndrome, a long-term complication exhibiting chronic inflammation and gut dysbiosis. Much effort is being expended to improve therapeutic outcomes. Human milk oligosaccharides (hMOS) are non-digestible carbohydrates known to exert health benefits in breastfed infants by preventing infection, maintaining immune homeostasis and nurturing healthy gut microbiota. These beneficial effects suggest the hypothesis that hMOS might have applications in COVID-19 as receptor decoys, immunomodulators, mucosal signaling agents, and prebiotics. This review summarizes hMOS biogenesis and classification, describes the possible mechanisms of action of hMOS upon different phases of SARS-CoV-2 infection, and discusses the challenges and opportunities of hMOS research for clinical applications in COVID-19.

Developing global guidance on human milk banking

Donor human milk is recommended by the World Health Organization both for its advantageous nutritional and biological properties when mother’s own milk is not available and for its recognized support for lactation and breastfeeding when used appropriately. An increasing number of human milk banks are being established around the world, especially in low- and middle-income countries, to facilitate the collection, processing and distribution of donor human milk. In contrast to other medical products of human origin, however, there are no minimum quality, safety and ethical standards for donor human milk and no coordinating global body to inform national policies. We present the key issues impeding progress in human milk banking, including the lack of clear definitions or registries of products; issues around regulation, quality and safety; and ethical concerns about commercialization and potential exploitation of women. Recognizing that progress in human milk banking is limited by a lack of comparable evidence, we recommend further research in this field to fill the knowledge gaps and provide evidence-based guidance. We also highlight the need for optimal support for mothers to provide their own breastmilk and establish breastfeeding as soon as and wherever possible after birth.

The clinical role of the gut microbiome and fecal microbiota transplantation in allogeneic stem cell transplantation

Outcomes of allogeneic hematopoietic stem cell transplantation (allo- HSCT) have improved in the recent decade; however, infections and graft-versus-host disease remain two leading complications significantly contributing to early transplant-related mortality. In past years, the human intestinal microbial composition (microbiota) has been found to be associated with various disease states, including cancer, response to cancer immunotherapy and to modulate the gut innate and adaptive immune response. In the setting of allo-HSCT, the intestinal microbiota diversity and composition appear to have an impact on infection risk, mortality and overall survival. Microbial metabolites have been shown to contribute to the health and integrity of intestinal epithelial cells during inflammation, thus mitigating graft-versus-host disease in animal models. While the cause-andeffect relationship between the intestinal microbiota and transplant-associated complications has not yet been fully elucidated, the above findings have already resulted in the implementation of various interventions aiming to restore the intestinal microbiota diversity and composition. Among others, these interventions include the administration of fecal microbiota transplantation. The present review, based on published data, is intended to define the role of the latter approach in the setting of allo-HSCT.

Donor Human Milk Use in Populations Other than the Preterm Infant: A Systematic Scoping Review

Introduction: Exclusive breastfeeding is recommended for an infant's first 6 months of life. If unable to breastfeed, expressed breast milk, including donor human milk (DHM), is recommended for optimal nutrition. Benefits of DHM in preterm infants have been established by extensive research. However, less is known about DHM use in other populations. Objective: To conduct a scoping review of the literature regarding DHM use in populations other than preterm infants. Materials and Methods: PubMed and Clinicaltrials.gov were used to search for articles and clinical trials published between January 1, 2000 and February 29, 2020. In total, 182 articles and reports were identified and screened by 2 independent reviewers. Results: Twenty-six articles met inclusion criteria and were reviewed. Studies were mostly observational in design and included infants born >35 weeks gestational age with health risks (9/26) and healthy infants (14/26). Most studies in infants with health risks (7/9) investigated clinical outcomes, with small, observational studies suggesting potential improvements in feeding tolerance and gastrointestinal health. Regarding healthy infants, no studies addressed growth, only one study measured clinical outcomes, and findings related to breastfeeding outcomes were conflicting. Over half of the studies reviewed (15/26) were not designed to establish a potential relationship between DHM use and relevant health-related outcomes. Conclusion: The current evidence of DHM use in populations other than preterm infants is limited by lack of direct health measures and infrequent use of randomized trials. More research is warranted to investigate clinical, growth, and breastfeeding outcomes.

Microbiota modification in hematology: still at the bench or ready for the bedside?

Growing evidence suggests that human microbiota likely influence diverse processes including hematopoiesis, chemotherapy metabolism, and efficacy, as well as overall survival in patients with hematologic malignancies and other cancers. Both host genetic susceptibility and host-microbiota interactions may impact cancer risk and response to treatment; however, microbiota have the potential to be uniquely modifiable and accessible targets for treatment. Here, we focus on strategies to modify microbiota composition and function in patients with cancer. First, we evaluate the use of fecal microbiota transplant to restore microbial equilibrium following perturbation by antibiotics and chemotherapy, and as a treatment of complications of hematopoietic stem cell transplantation (HSCT), such as graft-versus-host disease and colonization with multidrug-resistant organisms. We then address the potential use of both probiotics and dietary prebiotic compounds in targeted modulation of the microbiota intended to improve outcomes in hematologic diseases. With each type of therapy, we highlight the role that abnormal, or dysbiotic, microbiota play in disease, treatment efficacy, and toxicity and evaluate their potential promise as emerging strategies for microbiota manipulation in patients with hematologic malignancies and in those undergoing HSCT.

Formula Diet Alters the Ileal Metagenome and Transcriptome at Weaning and during the Postweaning Period in a Porcine Model

Exclusive breastfeeding impacts the intestinal microbiome and is associated with a better immune function than is seen with milk formula (MF) feeding in infants and yet with mechanisms poorly defined. The porcine model was used to evaluate the impact of MF on ileum microbial communities and gene expression relative to human milk (HM)-fed piglets. Fifty-two Dutch Landrace male piglets were fed an isocaloric diet of either HM (n = 26) or MF (n = 26) from day 2 through day 21 of age and weaned to a solid diet until day 51. Eleven piglets from each group were euthanized at day 21, while the remaining piglets (HM, n = 15; MF, n = 15) were euthanized at day 51 to collect ileal epithelium (EP) scrapings and ileal (IL) tissues. The epithelial mucosa was subjected to shotgun metagenome sequencing, and EP and IL tissues were used for transcriptome analysis. On day 21, transcriptome data revealed that the levels of pathways involved in inflammation and apoptosis were significantly higher in MF piglets than in HM piglets, whereas the levels of tight junctions and pathogen detection systems were lower in MF piglets than in HM piglets. The MF impacts on the small intestine were maintained over the postweaning period (day 51) as indicated by higher levels of Dialister invisus bacteria and higher levels of expression of genes associated with inflammation and apoptosis pathways relative to HM group. The current study demonstrated that MF might impact local intestinal inflammation, apoptosis, and tight junctions and might suppress pathogen recognition in the small intestine compared with HM.IMPORTANCE Exclusive human milk (HM) breastfeeding for the first 6 months of age in infants is recommended to improve health outcomes during early life and beyond. When women are unable to provide sufficient HM, milk formula (MF) is often recommended as a complementary or alternative source of nutrition. Previous studies in piglets demonstrated that MF alters the gut microbiome and induces inflammatory cytokine production. The links between MF feeding, gut microbiome, and inflammation status are unclear due to challenges associated with the collection of intestinal samples from human infants. The current report provides the first insight into MF-microbiome-inflammation connections in the small intestine compared with HM feeding using a porcine model. The present results showed that, compared with HM, MF might impact immune function through the induction of ileal inflammation, apoptosis, and tight junction disruptions and likely compromised immune defense against pathogen detection in the small intestine relative to piglets that were fed HM.

Clinical insights gained through metabolomic analysis of human breast milk

Introduction: Among the OMICS technologies, that have emerged in recent years, metabolomics has allowed relevant step forwards in clinical research. Several improvements in disease diagnosis and clinical management have been permitted, even in neonatology. Among potentially evaluable biofluids, breast milk (BM) results are highly interesting, representing a fluid of conjunction between mothers newborns, describing their interaction.Areas covered: in this review, updating a previous review article, we discuss research articles and reviews on BM metabolomics and found in MEDLINE using metabolomics, breast milk, neonatal nutrition, breastfeeding, human milk composition, and preterm neonates as keywords.Expert opinion: Our research group has a profound interest in metabolomics research. In 2012, we published the first metabolomic analysis on BM samples, reporting interesting data on its composition and relevant differences with formula milk (FM), useful to improve FM composition. As confirmed by successive studies, such technology can detect the specific BM composition and its dependence on several variables, including lactation stage, gestational age, maternal or environmental conditions. Moreover, since BM contaminants or drug levels can be detected, metabolomics also results useful to determine BM safety. These are only a few practical applications of BM analysis, which will be reviewed in this paper.

Microbiota modification in hematology: still at the bench or ready for the bedside?

Growing evidence suggests that human microbiota likely influence diverse processes including hematopoiesis, chemotherapy metabolism, and efficacy, as well as overall survival in patients with hematologic malignancies and other cancers. Both host genetic susceptibility and host-microbiota interactions may impact cancer risk and response to treatment; however, microbiota have the potential to be uniquely modifiable and accessible targets for treatment. Here, we focus on strategies to modify microbiota composition and function in patients with cancer. First, we evaluate the use of fecal microbiota transplant to restore microbial equilibrium following perturbation by antibiotics and chemotherapy, and as a treatment of complications of hematopoietic stem cell transplantation (HSCT), such as graft-versus-host disease and colonization with multidrug-resistant organisms. We then address the potential use of both probiotics and dietary prebiotic compounds in targeted modulation of the microbiota intended to improve outcomes in hematologic diseases. With each type of therapy, we highlight the role that abnormal, or dysbiotic, microbiota play in disease, treatment efficacy, and toxicity and evaluate their potential promise as emerging strategies for microbiota manipulation in patients with hematologic malignancies and in those undergoing HSCT.