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American Journal of Hematology Aug 2021The role of iron in the formation and functioning of erythrocytes, and to a lesser degree of white blood cells, is well established, but the relationship between iron... (Review)
Review
The role of iron in the formation and functioning of erythrocytes, and to a lesser degree of white blood cells, is well established, but the relationship between iron and platelets is less documented. Physiologically, iron plays an important role in hematopoiesis, including thrombopoiesis; iron levels direct, together with genetic factors, the lineage commitment of megakaryocytic/erythroid progenitors toward either megakaryocyte or erythroid progenitors. Megakaryocytic iron contributes to cellular machinery, especially energy production in platelet mitochondria. Thrombocytosis, possibly favoring vascular thrombosis, is a classical feature observed with abnormally low total body iron stores (mainly due to blood losses or decreased duodenal iron intake), but thrombocytopenia can also occur in severe iron deficiency anemia. Iron sequestration, as seen in inflammatory conditions, can be associated with early thrombocytopenia due to platelet consumption and followed by reactive replenishment of the platelet pool with possibility of thrombocytosis. Iron overload of genetic origin (hemochromatosis), despite expected mitochondrial damage related to ferroptosis, has not been reported to cause thrombocytopenia (except in case of high degree of hepatic fibrosis), and iron-related alteration of platelet function is still a matter of debate. In acquired iron overload (of transfusional and/or dyserythropoiesis origin), quantitative or qualitative platelet changes are difficult to attribute to iron alone due to the interference of the underlying hematological conditions; likewise, hematological improvement, including increased blood platelet counts, observed under iron oral chelation is likely to reflect mechanisms other than the sole beneficial impact of iron depletion.
Topics: Blood Platelets; Humans; Iron
PubMed: 33844865
DOI: 10.1002/ajh.26189 -
Cell Host & Microbe Sep 2022The intestinal epithelium plays critical roles in sensing and integrating dietary and microbial signals. How microbiota and intestinal epithelial cell (IEC) interactions...
The intestinal epithelium plays critical roles in sensing and integrating dietary and microbial signals. How microbiota and intestinal epithelial cell (IEC) interactions regulate host physiology in the proximal small intestine, particularly the duodenum, is unclear. Using single-cell RNA sequencing of duodenal IECs under germ-free (GF) and different conventional microbiota compositions, we show that specific microbiota members alter epithelial homeostasis by increasing epithelial turnover rate, crypt proliferation, and major histocompatibility complex class II (MHCII) expression. Microbiome profiling identified Faecalibaculum rodentium as a key species involved in this regulation. F. rodentium decreases enterocyte expression of retinoic-acid-producing enzymes Adh1, Aldh1a1, and Rdh7, reducing retinoic acid signaling required to maintain certain intestinal eosinophil populations. Eosinophils suppress intraepithelial-lymphocyte-mediated production of interferon-γ that regulates epithelial cell function. Thus, we identify a retinoic acid-eosinophil-interferon-γ-dependent circuit by which the microbiota modulates duodenal epithelial homeostasis.
Topics: Citrobacter rodentium; Eosinophils; Epithelial Cells; Firmicutes; Homeostasis; Interferon-gamma; Intestinal Mucosa; Tretinoin
PubMed: 35985335
DOI: 10.1016/j.chom.2022.07.015 -
Cell Metabolism Jan 2020Iron is a central micronutrient needed by all living organisms. Competition for iron in the intestinal tract is essential for the maintenance of indigenous microbial...
Iron is a central micronutrient needed by all living organisms. Competition for iron in the intestinal tract is essential for the maintenance of indigenous microbial populations and for host health. How symbiotic relationships between hosts and native microbes persist during times of iron limitation is unclear. Here, we demonstrate that indigenous bacteria possess an iron-dependent mechanism that inhibits host iron transport and storage. Using a high-throughput screen of microbial metabolites, we found that gut microbiota produce metabolites that suppress hypoxia-inducible factor 2α (HIF-2α) a master transcription factor of intestinal iron absorption and increase the iron-storage protein ferritin, resulting in decreased intestinal iron absorption by the host. We identified 1,3-diaminopropane (DAP) and reuterin as inhibitors of HIF-2α via inhibition of heterodimerization. DAP and reuterin effectively ameliorated systemic iron overload. This work provides evidence of intestine-microbiota metabolic crosstalk that is essential for systemic iron homeostasis.
Topics: Adolescent; Animals; Anti-Bacterial Agents; Basic Helix-Loop-Helix Transcription Factors; Cell Line; Cell Proliferation; Diamines; Dimerization; Duodenum; Feces; Female; Ferritins; Gastrointestinal Microbiome; Glyceraldehyde; Homeostasis; Humans; Iron; Lactobacillus; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Middle Aged; Organoids; Probiotics; Propane; Signal Transduction
PubMed: 31708445
DOI: 10.1016/j.cmet.2019.10.005 -
Gut Jul 2023In acute pancreatitis (AP), bacterial translocation and subsequent infection of pancreatic necrosis are the main risk factors for severe disease and late death....
OBJECTIVE
In acute pancreatitis (AP), bacterial translocation and subsequent infection of pancreatic necrosis are the main risk factors for severe disease and late death. Understanding how immunological host defence mechanisms fail to protect the intestinal barrier is of great importance in reducing the mortality risk of the disease. Here, we studied the role of the T/Th17 balance for maintaining the intestinal barrier function in a mouse model of severe AP.
DESIGN
AP was induced by partial duct ligation in C57Bl/6 or DEREG mice, in which regulatory T-cells (T) were depleted by intraperitoneal injection of diphtheria toxin. By flow cytometry, functional suppression assays and transcriptional profiling we analysed T activation and characterised T-cells of the lamina propria as well as intraepithelial lymphocytes (IELs) regarding their activation and differentiation. Microbiota composition was examined in intestinal samples as well as in murine and human pancreatic necrosis by 16S rRNA gene sequencing.
RESULTS
The prophylactic Tdepletion enhanced the proinflammatory response in an experimental mouse model of AP but stabilised the intestinal immunological barrier function of Th17 cells and CD8/γδTCR IELs. T depleted animals developed less bacterial translocation to the pancreas. Duodenal overgrowth of the facultative pathogenic taxa which associates with severe disease and infected necrosis was diminished in T depleted animals.
CONCLUSION
T play a crucial role in the counterbalance against systemic inflammatory response syndrome. In AP, T-activation disturbs the duodenal barrier function and permits translocation of commensal bacteria into pancreatic necrosis. Targeting T in AP may help to ameliorate the disease course.
Topics: Mice; Humans; Animals; T-Lymphocytes, Regulatory; Pancreatitis, Acute Necrotizing; Acute Disease; Bacterial Translocation; RNA, Ribosomal, 16S; Mice, Inbred C57BL
PubMed: 36631247
DOI: 10.1136/gutjnl-2022-327448 -
Gut Feb 2022Hydrothermal duodenal mucosal resurfacing (DMR) is a safe, outpatient endoscopic procedure. REVITA-2, a double-blind, superiority randomised controlled trial,... (Randomized Controlled Trial)
Randomized Controlled Trial
Safety and efficacy of hydrothermal duodenal mucosal resurfacing in patients with type 2 diabetes: the randomised, double-blind, sham-controlled, multicentre REVITA-2 feasibility trial.
OBJECTIVE
Hydrothermal duodenal mucosal resurfacing (DMR) is a safe, outpatient endoscopic procedure. REVITA-2, a double-blind, superiority randomised controlled trial, investigates safety and efficacy of DMR using the single catheter Revita system (Revita DMR (catheter and system)), on glycaemic control and liver fat content in type 2 diabetes (T2D).
DESIGN
Eligible patients (haemoglobin A1c (HbA1c) 59-86 mmol/mol, body mass index≥24 and ≤40 kg/m, fasting insulin >48.6 pmol/L, ≥1 oral antidiabetic medication) enrolled in Europe and Brazil. Primary endpoints were safety, change from baseline in HbA1c at 24 weeks, and liver MRI proton-density fat fraction (MRI-PDFF) at 12 weeks.
RESULTS
Overall mITT (DMR n=56; sham n=52), 24 weeks post DMR, median (IQR) HbA1c change was -10.4 (18.6) mmol/mol in DMR group versus -7.1 (16.4) mmol/mol in sham group (p=0.147). In patients with baseline liver MRI-PDFF >5% (DMR n=48; sham n=43), 12-week post-DMR liver-fat change was -5.4 (5.6)% in DMR group versus -2.9 (6.2)% in sham group (p=0.096). Results from prespecified interaction testing and clinical parameter assessment showed heterogeneity between European (DMR n=39; sham n=37) and Brazilian (DMR n=17; sham n=16) populations (p=0.063); therefore, results were stratified by region. In European mITT, 24 weeks post DMR, median (IQR) HbA1c change was -6.6 mmol/mol (17.5 mmol/mol) versus -3.3 mmol/mol (10.9 mmol/mol) post-sham (p=0.033); 12-week post-DMR liver-fat change was -5.4% (6.1%) versus -2.2% (4.3%) post-sham (p=0.035). Brazilian mITT results trended towards DMR benefit in HbA1c, but not liver fat, in context of a large sham effect. In overall PP, patients with high baseline fasting plasma glucose ((FPG)≥10 mmol/L) had significantly greater reductions in HbA1c post-DMR versus sham (p=0.002). Most adverse events were mild and transient.
CONCLUSIONS
DMR is safe and exerts beneficial disease-modifying metabolic effects in T2D with or without non-alcoholic liver disease, particularly in patients with high FPG.
TRIAL REGISTRATION NUMBER
NCT02879383.
Topics: Adult; Aged; Catheter Ablation; Diabetes Mellitus, Type 2; Double-Blind Method; Duodenum; Endoscopic Mucosal Resection; Feasibility Studies; Female; Glycated Hemoglobin; Humans; Hyperthermia, Induced; Intestinal Mucosa; Male; Middle Aged; Treatment Outcome
PubMed: 33597157
DOI: 10.1136/gutjnl-2020-323608 -
The Journal of Allergy and Clinical... Apr 2023Eosinophilic duodenitis (EoD), characterized by nonspecific gastrointestinal symptoms and increased numbers of duodenal eosinophils, may be in the eosinophilic...
BACKGROUND
Eosinophilic duodenitis (EoD), characterized by nonspecific gastrointestinal symptoms and increased numbers of duodenal eosinophils, may be in the eosinophilic gastrointestinal disease spectrum. However, diagnostic thresholds and pathogenic processes of duodenal tissue eosinophilia are inadequately characterized.
OBJECTIVE
We aimed to define an EoD transcriptome and pathologic pathways.
METHODS
RNA sequencing and histologic features of human duodenal biopsy samples were analyzed as a function of duodenal eosinophils levels. For analyses, we defined EoD as more than 52 peak eosinophils/hpf (n = 8), duodenal eosinophilia as 30 to 52 eosinophils/hpf (n = 11), and normal controls as fewer than 30 eosinophils/hpf (n = 8). Associations between gene expression and histologic features were analyzed with Spearman correlation.
RESULTS
We identified 382 differentially expressed genes (EoD transcriptome) between EoD and normal controls (>2-fold change [adjusted P < .05]). The EoD transcriptome distinguished EoD from controls (duodenal eosinophilia and normal controls). The duodenal eosinophil count was correlated with a distinct EoD transcriptome when 50 to 60 peak eosinophils/hpf were present. The EoD transcriptome was enriched in genes involved in IL-4/IL-13 signaling, mast cells, and myeloid progenitor cells. Among duodenal histologic features, lamina propria eosinophil sheets was the most associated with transcriptomic changes (r = 0.66; P < .01). EoD gene signatures were shared with eosinophilic esophagitis and eosinophilic gastritis but not with eosinophilic colitis or celiac disease.
CONCLUSION
We have identified an EoD transcriptomic signature that emerges at 50 to 60 peak eosinophils/hpf and established EoD as part of a spectrum of upper eosinophilic gastrointestinal disorder associated with type 2 immunity and distinct from eosinophilic colitis and celiac disease. These findings provide a basis for improving diagnosis and treatment.
Topics: Humans; Celiac Disease; Eosinophils; Eosinophilic Esophagitis; Colitis
PubMed: 36592704
DOI: 10.1016/j.jaci.2022.12.814 -
Ugeskrift For Laeger Aug 2023In this case report, we present a 70-year-old male who was brought to our hospital with signs of upper gastrointestinal bleeding. The patient was diagnosed with aortitis...
In this case report, we present a 70-year-old male who was brought to our hospital with signs of upper gastrointestinal bleeding. The patient was diagnosed with aortitis two and a half months prior. We suspected upper gastrointestinal bleeding, and the patient was taken to the operating room for an acute endoscopy, which showed blood in the oesophagus, ventricle, and duodenum, but no bleeding source. CT angiography showed erosion of aortic aneurism, at the site of known aortitis, with bleeding into the lung and pleura. The patient was transported to the nearest university hospital for thoracic endovascular repair and survived.
Topics: Male; Humans; Aged; Hematemesis; Hemoptysis; Aortitis; Gastrointestinal Hemorrhage; Aortic Aneurysm; Hospitals, University
PubMed: 37767877
DOI: No ID Found -
The American Journal of Medicine Oct 2022The role of antisecretory drugs for the prevention of upper gastrointestinal bleeding in patients using anticoagulants is unclear. We investigated this question in a... (Meta-Analysis)
Meta-Analysis
BACKGROUND
The role of antisecretory drugs for the prevention of upper gastrointestinal bleeding in patients using anticoagulants is unclear. We investigated this question in a systematic review and meta-analysis.
METHODS
We searched Embase, PubMed, Web of Science, Scopus, the Cochrane Library, and clinicaltrials.gov thru April 2021 for controlled randomized trials and observational studies evaluating the association of proton pump inhibitors (PPIs) or H2-receptor antagonists with overt upper gastrointestinal bleeding in patients using anticoagulants. Independent duplicate review, data extraction, and risk of bias assessment were performed. Observational studies were included only if they provided results controlled for at least 2 variables. Meta-analyses were performed using random effects models.
RESULTS
Six observational studies and 1 randomized trial were included. All but 1 study had low risk of bias. None of the studies excluded patients with concomitant aspirin or nonsteroidal anti-inflammatory drug use. For PPIs, the pooled relative risk of upper gastrointestinal bleeding was 0.67 (95% confidence interval 0.61, 0.74) with low statistical heterogeneity (I = 15%). Individual studies showed greater treatment effect in patients with higher risk for upper gastrointestinal bleeding (eg, nonsteroidal anti-inflammatory drug or aspirin use, elevated bleeding risk score). A single observational study evaluating the association of H2-receptor antagonists with upper gastrointestinal bleeding found a relative risk of 0.69 (95% confidence interval 0.24-2.02).
CONCLUSIONS
Evidence drawn mostly from observational studies with low risk of bias demonstrate that PPIs reduce upper gastrointestinal bleeding in patients prescribed oral anticoagulants. The benefit appears to be most clearcut and substantial in patients with elevated risk of upper gastrointestinal bleeding.
Topics: Anti-Inflammatory Agents, Non-Steroidal; Anticoagulants; Aspirin; Gastrointestinal Agents; Gastrointestinal Hemorrhage; Histamine H2 Antagonists; Humans; Observational Studies as Topic; Proton Pump Inhibitors
PubMed: 35679879
DOI: 10.1016/j.amjmed.2022.05.031 -
Scientific Reports Jul 2023The gut microbiome influences the pathogenesis and course of metabolic disorders such as diabetes. While it is likely that duodenal mucosa associated microbiota...
The gut microbiome influences the pathogenesis and course of metabolic disorders such as diabetes. While it is likely that duodenal mucosa associated microbiota contributes to the genesis and progression of increased blood sugar, including the pre-diabetic stage, it is much less studied than stool. We investigated paired stool and duodenal microbiota in subjects with hyperglycemia (HbA1c ≥ 5.7% and fasting plasma glucose > 100 mg/dl) compared to normoglycemic. We found patients with hyperglycemia (n = 33) had higher duodenal bacterial count (p = 0.008), increased pathobionts and reduction in beneficial flora compared to normoglycemic (n = 21). The microenvironment of duodenum was assessed by measuring oxygen saturation using T-Stat, serum inflammatory markers and zonulin for gut permeability. We observed that bacterial overload was correlated with increased serum zonulin (p = 0.061) and higher TNF-α (p = 0.054). Moreover, reduced oxygen saturation (p = 0.021) and a systemic proinflammatory state [increased total leukocyte count (p = 0.031) and reduced IL-10 (p = 0.015)] characterized the duodenum of hyperglycemic. Unlike stool flora, the variability in duodenal bacterial profile was associated with glycemic status and was predicted by bioinformatic analysis to adversely affect nutrient metabolism. Our findings offer new understanding of the compositional changes in the small intestine bacteria by identifying duodenal dysbiosis and altered local metabolism as potentially early events in hyperglycemia.
Topics: Humans; Dysbiosis; Duodenum; Hyperglycemia; Diabetes Mellitus; Gastrointestinal Microbiome; Bacteria
PubMed: 37419941
DOI: 10.1038/s41598-023-37720-x