Early stool microbiome and metabolome signatures in pediatric patients undergoing allogeneic hematopoietic cell transplantation.

2021

e29384

2021 Oct 28

1545-5017

<p><strong>BACKGROUND: </strong>The contribution of the gastrointestinal tract microbiome to outcomes after allogeneic hematopoietic cell transplantation (HCT) is increasingly recognized. Investigations of larger pediatric cohorts aimed at defining the microbiome state and associated metabolic patterns pretransplant are needed.</p>

<p><strong>METHODS: </strong>We sought to describe the pretransplant stool microbiome in pediatric allogenic HCT patients at four centers. We performed shotgun metagenomic sequencing and untargeted metabolic profiling on pretransplant stool samples. Samples were compared with normal age-matched controls and by clinical characteristics. We then explored associations between stool microbiome measurements and metabolite concentrations.</p>

<p><strong>RESULTS: </strong>We profiled stool samples from 88 pediatric allogeneic HCT patients, a median of 4&nbsp;days before transplant. Pretransplant stool samples differed from healthy controls based on indices of alpha diversity and in the proportional abundance of specific taxa and bacterial genes. Relative to stool from healthy patients, samples from HCT patients had decreased proportion of Bacteroides, Ruminococcaeae, and genes involved in butyrate production, but were enriched for gammaproteobacterial species. No systematic differences in stool microbiome or metabolomic profiles by age, transplant indication, or hospital were noted. Stool metabolites demonstrated strong correlations with microbiome composition.</p>

<p><strong>DISCUSSION: </strong>Stool samples from pediatric allogeneic HCT patients demonstrate substantial dysbiosis early in the transplant course. As microbiome disruptions associate with adverse transplant outcomes, pediatric-specific analyses examining longitudinal microbiome and metabolome changes are imperative to identify causal associations and to inform rational design of interventions.</p>

10.1002/pbc.29384

Pediatr Blood Cancer

34709713

Decreased Intestinal Microbiome Diversity in Pediatric Sepsis: A Conceptual Framework for Intestinal Dysbiosis to Influence Immunometabolic Function.

2021

e0360

2021 Mar

2639-8028

<p><b>Objectives: </b>The intestinal microbiome can modulate immune function through production of microbial-derived short-chain fatty acids. We explored whether intestinal dysbiosis in children with sepsis leads to changes in microbial-derived short-chain fatty acids in plasma and stool that are associated with immunometabolic dysfunction in peripheral blood mononuclear cells.</p><p><b>Design: </b>Prospective observational pilot study.</p><p><b>Setting: </b>Single academic PICU.</p><p><b>Patients: </b>Forty-three children with sepsis/septic shock and 44 healthy controls.</p><p><b>Measurements and Main Results: </b>Stool and plasma samples were serially collected for sepsis patients; stool was collected once for controls. The intestinal microbiome was assessed using 16S ribosomal RNA sequencing and alpha- and beta-diversity were determined. We measured short-chain fatty acids using liquid chromatography, peripheral blood mononuclear cell mitochondrial respiration using high-resolution respirometry, and immune function using ex vivo lipopolysaccharide-stimulated whole blood tumor necrosis factor-α. Sepsis patients exhibited reduced microbial diversity compared with healthy controls, with lower alpha- and beta-diversity. Reduced microbial diversity among sepsis patients (mainly from lower abundance of commensal obligate anaerobes) was associated with increased acetic and propionic acid and decreased butyric, isobutyric, and caproic acid. Decreased levels of plasma butyric acid were further associated with lower peripheral blood mononuclear cell mitochondrial respiration, which in turn, was associated with lower lipopolysaccharide-stimulated tumor necrosis factor-α. However, neither intestinal dysbiosis nor specific patterns of short-chain fatty acids were associated with lipopolysaccharide-stimulated tumor necrosis factor-α.</p><p><b>Conclusions: </b>Intestinal dysbiosis was associated with altered short-chain fatty acid metabolites in children with sepsis, but these findings were not linked directly to mitochondrial or immunologic changes. More detailed mechanistic studies are needed to test the role of microbial-derived short-chain fatty acids in the progression of sepsis.</p>

10.1097/CCE.0000000000000360

Crit Care Explor

33786436

Gut Microbiome Profile After Pancreatectomy in Infants With Congenital Hyperinsulinism.

2021

89-92

2021 Jan 01

1536-4828

<p><strong>OBJECTIVES: </strong>The objective of this study was to characterize gut microbiome profiles of infants with congenital hyperinsulinism (HI) who underwent near-total or partial pancreatectomy for hypoglycemia management, as compared with healthy controls.</p>

<p><strong>METHODS: </strong>A prospective observational cohort study was performed. Subjects were infants (0-6 months) with HI who underwent removal of pancreatic tissue for management of intractable hypoglycemia from February 2017 to February 2018 at the Children's Hospital of Philadelphia. Fecal samples were collected postoperatively, on full enteral nutrition. The gut microbiome of HI subjects was analyzed and compared with age-matched samples from healthy infants.</p>

<p><strong>RESULTS: </strong>Seven subjects with ≥50% pancreatectomy and 6 with &lt;50% pancreatectomy were included. α (within-sample) diversity was lowest among infants with ≥50% pancreatectomy (richness: false discovery rate, 0.003; Shannon index: false discovery rate, 0.01). β (between-sample) diversity (Bray-Curtis dissimilarity, P = 0.02; Jaccard distance, P = 0.001) differed across groups (≥ or &lt;50% pancreatectomy, controls). Bifidobacteria and Klebsiella species were least abundant among infants with ≥50% pancreatectomy but did not differ between infants with &lt;50% pancreatectomy and historical controls.</p>

<p><strong>CONCLUSIONS: </strong>Infants with HI who underwent ≥50% pancreatectomy differed from age-matched infants in gut microbiome profile, whereas those with &lt;50% pancreatectomy more closely resembled control profiles. The durability of this difference should be investigated.</p>

10.1097/MPA.0000000000001708

Pancreas

33370028

Perturbations of the Gut Microbiome and Metabolome in Children with Calcium Oxalate Kidney Stone Disease.

2020

2020 May 07

1533-3450

<p><strong>BACKGROUND: </strong>The relationship between the composition and function of gut microbial communities and early-onset calcium oxalate kidney stone disease is unknown.</p>

<p><strong>METHODS: </strong>We conducted a case-control study of 88 individuals aged 4-18 years, which included 44 individuals with kidney stones containing ≥50% calcium oxalate and 44 controls matched for age, sex, and race. Shotgun metagenomic sequencing and untargeted metabolomics were performed on stool samples.</p>

<p><strong>RESULTS: </strong>Participants who were kidney stone formers had a significantly less diverse gut microbiome compared with controls. Among bacterial taxa with a prevalence &gt;0.1%, 31 taxa were less abundant among individuals with nephrolithiasis. These included seven taxa that produce butyrate and three taxa that degrade oxalate. The lower abundance of these bacteria was reflected in decreased abundance of the gene encoding butyryl-coA dehydrogenase (=0.02). The relative abundance of these bacteria was correlated with the levels of 18 fecal metabolites, and levels of these metabolites differed in individuals with kidney stones compared with controls. The oxalate-degrading bacterial taxa identified as decreased in those who were kidney stone formers were components of a larger abundance correlation network that included and several species. The microbial () diversity was associated with age of stone onset, first decreasing and then increasing with age. For the individuals who were stone formers, we found the lowest diversity among individuals who first formed stones at age 9-14 years, whereas controls displayed no age-related differences in diversity.</p>

<p><strong>CONCLUSIONS: </strong>Loss of gut bacteria, particularly loss of those that produce butyrate and degrade oxalate, associates with perturbations of the metabolome that may be upstream determinants of early-onset calcium oxalate kidney stone disease.</p>

10.1681/ASN.2019101131

J. Am. Soc. Nephrol.

32381601