Oral versus intravenous iron replacement therapy distinctly alters the gut microbiota and metabolome in patients with IBD

The role of oral iron in the treatment of adults with iron deficiency

Iron deficiency is the most common nutrient deficiency in the world, affecting over 20% of premenopausal women worldwide. Oral iron supplementation is often the first-line treatment for the acute and chronic management of iron deficiency due to its ease and accessibility. However, there is no consensus on the optimal formulation or dosing strategy, or which patients should be preferentially treated with intravenous iron. Management of iron deficiency is complicated by the hepcidin-ferroportin iron regulatory pathway, which has evolved to prevent iron overload and thereby creates an inherent limit on gastrointestinal iron uptake and efficacy of oral iron. Unabsorbed iron propagates many of the side effects that complicate oral iron use including dyspepsia and constipation, all of which can thus be exacerbated by excessive oral iron doses. Daily low dose and every other day dosing protocols have attempted to bypass this physiologic bottleneck to allow for effective absorption and limit side effects; however, this approach has still resulted in low fractional iron absorption. In the following manuscript, we review the pathophysiology of iron absorption and current evidence for various preparations of oral iron. Lastly, we highlight opportunities for further study to advance the care of individuals affected by iron deficiency.

Poria cocos oligosaccharides ameliorate dextran sodium sulfate-induced colitis mice by regulating gut microbiota dysbiosis

Poria cocos, a widely accepted function food in China, has multiple pharmacological activities. This study aimed to investigate the therapeutic effect and molecular mechanism of Poria cocos oligosaccharides (PCOs) against dextran sodium sulfate (DSS)-induced mouse colitis. In this study, BALB/c mice were treated with 3% (w/v) DSS for seven days to establish a colitis model. The results showed that oral administration of PCOs (200 mg per kg per day) significantly reversed the changes in the physiological indices in colitis mice, including body weight, disease activity index scores (DAI), spleen index, and colon length. From the qRT-PCR assay, it was observed that PCOs suppressed the mRNA expression of pro-inflammatory cytokines, such as Tnf-α, Il-1β, and Il-6. In addition, PCOs protected the intestinal barrier from damage by promoting the expression of mucins and tight junction proteins at both mRNA and protein levels. Upon 16S rDNA sequencing, it was observed that PCO treatment partly reversed the changes in the gut microbiota of colitis mice by selectively regulating the abundance of specific bacteria. And Odoribacter, Muribaculum, Desulfovibrio, Oscillibacter, Escherichia-Shigella, and Turicibacter might be the critical bacteria in improving colitis via PCOs. Finally, using antibiotic mixtures to destroy the intestinal bacteria, we documented that PCO fermentation broth (PCO FB) instead of PCOs prevented the occurrence of colitis in gut microbiota-depleted mice. In conclusion, PCOs showed a protective effect on colitis by reversing gut microbiota dysbiosis. Our study sheds light on the potential application of PCOs as a prebiotic for treating colitis.

Iron in infectious diseases friend or foe?: The role of gut microbiota

Iron is a trace element involved in metabolic functions for all organisms, from microorganisms to mammalians. Iron deficiency is a prevalent health problem that affects billions of people worldwide, and iron overload could have some hazardous effect. The complex microbial community in the human body, also called microbiota, influences the host immune defence against infections. An imbalance in gut microbiota, dysbiosis, changes the host's susceptibility to infections by regulating the immune system. In recent years, the number of studies on the relationship between infectious diseases and microbiota has increased. Gut microbiota is affected by different parameters, including mode of delivery, hygiene habits, diet, drugs, and plasma iron levels during the lifetime. Gut microbiota may influence iron levels in the body, and iron overload and deficiency can also affect gut microbiota composition. Novel researches on microbiota shed light on the fact that the bidirectional interactions between gut microbiota and iron play a role in the pathogenesis of many diseases, especially infections. A better understanding of these interactions may help us to comprehend the pathogenesis of many infectious and metabolic diseases affecting people worldwide and following the development of more effective preventive and/or therapeutic strategies. In this review, we aimed to present the iron-mediated host-gut microbiota interactions, susceptibility to bacterial infections, and iron-targeted therapy approaches for infections.

Accumulation of Black Carbon Particles in Placenta, Cord Blood, and Childhood Urine in Association with the Intestinal Microbiome Diversity and Composition in Four- to Six-Year-Old Children in the ENVIRONAGE Birth Cohort

BACKGROUND

The gut microbiome plays an essential role in human health. Despite the link between air pollution exposure and various diseases, its association with the gut microbiome during susceptible life periods remains scarce.

OBJECTIVES

In this study, we examined the association between black carbon particles quantified in prenatal and postnatal biological matrices and bacterial richness and diversity measures, and bacterial families.

METHODS

A total of 85 stool samples were collected from 4- to 6-y-old children enrolled in the ENVIRonmental influence ON early AGEing birth cohort. We performed 16S rRNA gene sequencing to calculate bacterial richness and diversity indices (Chao1 richness, Shannon diversity, and Simpson diversity) and the relative abundance of bacterial families. Black carbon particles were quantified via white light generation under femtosecond pulsed laser illumination in placental tissue and cord blood, employed as prenatal exposure biomarkers, and in urine, used as a post-natal exposure biomarker. We used robust multivariable-adjusted linear models to examine the associations between quantified black carbon loads and measures of richness (Chao1 index) and diversity (Shannon and Simpson indices), adjusting for parity, season of delivery, sequencing batch, age, sex, weight and height of the child, and maternal education. Additionally, we performed a differential relative abundance analysis of bacterial families with a correction for sampling fraction bias. Results are expressed as percentage difference for a doubling in black carbon loads with 95% confidence interval (CI).

RESULTS

Two diversity indices were negatively associated with placental black carbon [Shannon: -4.38% (95% CI: -8.31%, -0.28%); Simpson: -0.90% (95% CI: -1.76%, -0.04%)], cord blood black carbon [Shannon: -3.38% (95% CI: -5.66%, -0.84%); Simpson: -0.91 (95% CI: -1.66%, -0.16%)], and urinary black carbon [Shannon: -3.39% (95% CI: -5.77%, -0.94%); Simpson: -0.89% (95% CI: -1.37%, -0.40%)]. The explained variance of black carbon on the above indices varied from 6.1% to 16.6%. No statistically significant associations were found between black carbon load and the Chao1 richness index. After multiple testing correction, placental black carbon was negatively associated with relative abundance of the bacterial families Defluviitaleaceae and Marinifilaceae, and urinary black carbon with Christensenellaceae and Coriobacteriaceae; associations with cord blood black carbon were not statistically significant after correction.

CONCLUSION

Black carbon particles quantified in prenatal and postnatal biological matrices were associated with the composition and diversity of the childhood intestinal microbiome. These findings address the influential role of exposure to air pollution during pregnancy and early life in human health. https://doi.org/10.1289/EHP11257.

Anemia in patients with inflammatory bowel disease as a risk factor for restless legs syndrome. Literature review

Restless legs syndrome (RLS) is a neurological, sensorimotor disorder. It is characterized by the uncomfortable and unpleasant sensations in the legs which begin or worsen during periods of rest, primarily in the evening or night, and are relieved by movement. Central iron deficiency plays a vital role in the pathogenesis of RLS. There is evidence that chronic inflammation is an additional risk factor for RLS. Anemia is the most common complication and extraintestinal manifestation of inflammatory bowel disease, therefore the prevalence of RLS in these patients is a problem of great interest. In addition, inflammatory bowel disease patients’ sleep disturbances directly influence the disease’s clinical course and can be the preclinical marker of exacerbation. It is essential for clinicians to be aware of RLS as a possible reason for sleep disturbance and as a factor that negatively affects the quality of life in inflammatory bowel disease patients.

Vitamin C improves gut Bifidobacteria in humans

Aims: Numerous beneficial effects of vitamin C (ascorbic acid) supplementation have been reported in the literature. However, data on its effects toward the gut microbiome are limited. We assessed the effect of vitamin C supplementation on the abundance of beneficial bacterial species in the gut microbiome. Materials and methods: Stool samples were analyzed for relative abundance of gut microbiome bacteria using next-generation sequencing-based profiling and metagenomic shotgun analysis. Results: Supplementation with vitamin C increased the abundance of bacteria of the genus Bifidobacterium (p = 0.0001) and affected various species. Conclusion: The beneficial effects of vitamin C supplementation may be attributed to modulation of the gut microbiome and the consequent health benefits thereof.

Houttuynia cordata polysaccharides alleviate ulcerative colitis by restoring intestinal homeostasis

Houttuynia cordata is traditionally used as phytoantibiotics for treating lung disease in China. Houttuynia cordata polysaccharides (HCPs) have been reported to alleviate influenza virus-induced intestinal and lung immune injury by regulating the gut-lung axis. The present study aims to investigate the effects and mechanisms of HCPs on ulcerative colitis (UC). Male C57BL/6 mice were induced by dextran sodium sulfate (DSS) to establish the UC animal model. Our results showed that HCPs significantly reduced the weight loss and the shortening of colon length in colitis mice, and relieved the pathological damage of colon mucosa and inhibited the expression of pro-inflammatory cytokines such as TNF-α, IL-1β, IL-6, etc. It was suggested that HCPs could significantly improve DSS-induced colitis in mice. HCPs directly protected intestinal epithelial cells, ameliorated epithelial barrier dysfunction and cell apoptosis, which was also proved in H₂O₂ stimulated cell apoptosis model. HCPs inhibited inflammation in the colon, which was related to suppressing the infiltration of macrophages, inhibiting the expression of pro-inflammatory cytokines and proteins (TLR4, NF-κB), and restoring the dysfunction of Th17 and Treg cells. HCPs also restored the alteration of intestinal flora induced by DSS, increased the abundance ofFirmicutes and Bacteroides, and reduced the abundance of Proteobacteria. This study confirmed the protective effect of Houttuynia cordata polysaccharide extracted from traditional Chinese medicine on ulcerative colitis, of which the mechanism was closely related to the maintenance of intestinal homeostasis (intestinal barrier, immune cells, and intestinal bacteria).

Nano-formulations in treatment of iron deficiency anaemia: An overview

BACKGROUND

Iron deficiency anaemia (IDA) is a significant challenge to global health. The absorption and bioavailability depend on the delivery vehicle being used. Ferrous sulphate is a drug of choice for IDA but leads to frequent gastrointestinal tract side effects that force the patient to discontinue the treatment. Gastrointestinal side effects result from converting bivalent iron into trivalent iron accompanied by reactive oxygen species (ROS) formation. Due to lower absorption, oral preparations of trivalent iron are recommended in patients with intolerance to ferrous sulphate. Nanosized iron preparation can resolved these concerns. The particle size of iron salts has been observed to have a significant impact on iron absorption. The surface area of iron compounds is increased by reducing their particle size, which improves their solubility in gastric juice and boosts their absorption. Sucrosomial iron, ferric citrate complexes, and ferric maltol are some of the novel iron preparations that ensure high bioavailability and good tolerance in chronic kidney disease, congestive heart failure, and inflammatory bowel disease. However, the parenteral route of administration of iron is unacceptable to most patients. Moreover, it leads to high free iron levels in circulation, resulting in ROS generation.

CONCLUSION

This article provides an informative summary of iron deficiency anaemia causes and treatment through nanoformulations and literature and in-depth patent analysis.

The role of iron in chronic inflammatory diseases: from mechanisms to treatment options in anemia of inflammation

Anemia of inflammation (AI) is a highly prevalent comorbidity in patients affected by chronic inflammatory disorders, such as chronic kidney disease, inflammatory bowel disease, or cancer, that negatively affect disease outcome and quality of life. The pathophysiology of AI is multifactorial, with inflammatory hypoferremia and iron-restricted erythropoiesis playing a major role in the context of disease-specific factors. Here, we review the recent progress in our understanding of the molecular mechanisms contributing to iron dysregulation in AI, the impact of hypoferremia and anemia on the course of the underlying disease, and (novel) therapeutic strategies applied to treat AI.

Iron deficiency screening is a key issue in chronic inflammatory diseases: A call to action

Iron deficiency is frequent in patients with chronic inflammatory conditions (e.g., chronic heart failure, chronic kidney disease, cancers, and bowel inflammatory diseases). Indeed, high concentrations of inflammatory cytokines increase hepcidin concentrations that lead to the sequestration of iron in cells of the reticuloendothelial system (functional iron deficiency). Iron parameters are often assessed only in the context of anemia, but iron deficiency, even without anemia, is present in about half of patients with inflammatory conditions. Iron deficiency worsens underlying chronic diseases and is an independent factor of morbidity and mortality. In daily practice, the most effective biomarkers of iron status are serum ferritin, which reflects iron storage, and transferrin saturation, which reflects the transport of iron. Serum ferritin is increased in an inflammatory context, and there is still no consensus on the threshold to be used in chronic inflammatory conditions. Nevertheless, recent recommendations of international guidelines agreed to define iron deficiency by serum ferritin <100 µg/L and/or transferrin saturation <20%. Iron parameters remain, however, insufficiently assessed in patients with chronic inflammatory conditions. Indeed, clinical symptoms of iron deficiency, such as fatigue, are not specific and often confused with those of the primary disease. Iron repletion, preferably by the intravenous route to bypass tissue sequestration, improves clinical signs and quality of life. Because of the negative impact of iron deficiency on chronic inflammatory diseases and the efficacy of intravenous iron repletion, screening of iron parameters should be part of the routine examination of all patients with chronic inflammatory diseases.

Mammary Leukocyte-Assisted Nanoparticle Transport Enhances Targeted Milk Trace Mineral Delivery

Nanoparticles are applied as versatile platforms for drug/gene delivery in many applications owing to their long-retention and specific targeting properties in living bodies. However, the delivery mechanism and the beneficial effect of nanoparticle-retention in many organisms remain largely uncertain. Here, the transport and metabolism of mineral nanoparticles in mammary gland during lactation are explored. It is shown that maternal intravenous administration of iron oxide nanoparticles (IONPs; diameter: ≈11.0 nm, surface charge: -29.1 mV, surface area: 1.05 m2 g-1 ) provides elevated iron delivery to mammary gland and increased iron secretion into breast milk, which is inaccessible by classical iron-ion transport approaches such as the transferrin receptor-mediated endocytic pathway. Mammary macrophages and neutrophils are found to play dominant roles in uptake and delivery of IONPs through an unconventional leukocyte-assisted iron secretion pathway. This pathway bypasses the tight iron concentration regulation of liver hepcidin-ferroportin axis and mammary epithelial cells to increase milk iron-ion content derived from IONPs. This work provides keen insight into the metabolic pathway of nanoparticles in mammary gland while offering a new scheme of nutrient delivery for neonate metabolism regulation by using nanosized nutrients.

Interactive Relationships between Intestinal Flora and Bile Acids

The digestive tract is replete with complex and diverse microbial communities that are important for the regulation of multiple pathophysiological processes in humans and animals, particularly those involved in the maintenance of intestinal homeostasis, immunity, inflammation, and tumorigenesis. The diversity of bile acids is a result of the joint efforts of host and intestinal microflora. There is a bidirectional relationship between the microbial community of the intestinal tract and bile acids in that, while the microbial flora tightly modulates the metabolism and synthesis of bile acids, the bile acid pool and composition affect the diversity and the homeostasis of the intestinal flora. Homeostatic imbalances of bile acid and intestinal flora systems may lead to the development of a variety of diseases, such as inflammatory bowel disease (IBD), colorectal cancer (CRC), hepatocellular carcinoma (HCC), type 2 diabetes (T2DM), and polycystic ovary syndrome (PCOS). The interactions between bile acids and intestinal flora may be (in)directly involved in the pathogenesis of these diseases.

Understanding the Potential and Risk of Bacterial Siderophores in Cancer

Siderophores are iron chelating molecules produced by nearly all organisms, most notably by bacteria, to efficiently sequester the limited iron that is available in the environment. Siderophores are an essential component of mammalian iron homeostasis and the ongoing interspecies competition for iron. Bacteria produce a broad repertoire of siderophores with a canonical role in iron chelation and the capacity to perform versatile functions such as interacting with other microbes and the host immune system. Siderophores are a vast area of untapped potential in the field of cancer research because cancer cells demand increased iron concentrations to sustain rapid proliferation. Studies investigating siderophores as therapeutics in cancer generally focused on the role of a few siderophores as iron chelators; however, these studies are limited and some show conflicting results. Moreover, siderophores are biologically conserved, structurally diverse molecules that perform additional functions related to iron chelation. Siderophores also have a role in inflammation due to their iron acquisition and chelation properties. These diverse functions may contribute to both risks and benefits as therapeutic agents in cancer. The potential of siderophore-mediated iron and bacterial modulation to be used in the treatment of cancer warrants further investigation. This review discusses the wide range of bacterial siderophore functions and their utilization in cancer treatment to further expand their functional relevance in cancer detection and treatment.

Effects of Dietary Nutrients on Fatty Liver Disease Associated With Metabolic Dysfunction (MAFLD): Based on the Intestinal-Hepatic Axis

Non-alcoholic fatty liver disease (NAFLD) has recently become the most common liver disease with a global prevalence of over 25% and is expected to increase. Recently, experts have reached a consensus that “fatty liver disease associated with metabolic dysfunction or MAFLD” may be a more appropriate and inclusive definition than NAFLD. Like the former name NAFLD, MAFLD, as a manifestation of multiple system metabolic disorders involving the liver, has certain heterogeneity in its pathogenesis, clinical manifestations, pathological changes and natural outcomes. We found that there is a delicate dynamic balance among intestinal microflora, metabolites and host immune system to maintain a healthy intestinal environment and host health. On the contrary, this imbalance is related to diseases such as MAFLD. However, there are no clear studies on how dietary nutrients affect the intestinal environment and participate in the pathogenesis of MAFLD. This review summarizes the interactions among dietary nutrients, intestinal microbiota and MAFLD in an attempt to provide evidence for the use of dietary supplements to regulate liver function in patients with MAFLD. These dietary nutrients influence the development and progression of MAFLD mainly through the hepatic-intestinal axis by altering dietary energy absorption, regulating bile acid metabolism, changing intestinal permeability and producing ethanol. Meanwhile, the nutrients have the ability to combat MAFLD in terms of enriching abundance of intestinal microbiota, reducing Firmicutes/Bacteroidetes ratio and promoting abundance of beneficial gut microbes. Therefore, family therapy with MAFLD using a reasonable diet could be considered.

Dietary High Dose of Iron Aggravates the Intestinal Injury but Promotes Intestinal Regeneration by Regulating Intestinal Stem Cells Activity in Adult Mice With Dextran Sodium Sulfate-Induced Colitis

The effects of excessive dietary iron intake on the body have been an important topic. The purpose of this study was to investigate the effects of high-dose iron on intestinal damage and regeneration in dextran sodium sulfate (DSS)-induced colitis model mice. A total of 72 8-week-old adult C57BL/6 mice were randomly divided into two dietary treatment groups: the basal diet supplemented with 45 (control) and 450 mg/kg iron (high-iron) from ferrous sulfate. The mice were fed different diets for 2 weeks, and then 2.5% DSS was orally administered to all mice for 7 days. Samples of different tissues were collected on days 0, 3, and 7 post administration (DPA). High-iron treatment significantly decreased the relative weight of the large intestine at 7 DPA but not at 0 DPA or 3 DPA. High dietary iron increased the jejunal villus width at 0 DPA, decreased the villus width and the crypt depth of the jejunum at 3 DPA, and decreased the number of colonic crypts at 7 DPA. Meanwhile, high dietary iron decreased the number of goblet cells in the jejunal villi and the Paneth cells in the jejunal crypts at 0 DPA, increased the number of goblet cells per crypt of the colon at 3 DPA, and the number of Paneth cells in the jejunal crypts, the goblet cells in the colon, the Ki67-positive proliferating cells in the colon, and the Sex-determining region Y-box transcription factor 9⁺ (SOX9) cells in the jejunum crypts and colon at 7 DPA. The organoid formation rate was increased by high-iron treatments at 3 DPA and 7 DPA. High dietary iron treatment decreased the mRNA level of jejunal jagged canonical Notch ligand 2 (Jag-2) at 0 DPA and bone morphogenetic protein 4 (Bmp4) and neural precursor cell-expressed developmentally downregulated 8 (Nedd8) in the jejunum and colon at 7 DPA, whereas it increased the mRNA expression of the serum/glucocorticoid-regulated kinase 1 (Sgk1) in the colon at 3 DPA. The results suggested that a high dose of iron aggravated intestinal injury but promoted intestinal repair by regulating intestinal epithelial cell renewal and intestinal stem cell activity in adult mice with colitis.

DivCom: A Tool for Systematic Partition of Groups of Microbial Profiles Into Intrinsic Subclusters and Distance-Based Subgroup Comparisons

When analyzing microbiome data, one of the main objectives is to effectively compare the microbial profiles of samples belonging to different groups. Beta diversity measures the level of similarity among samples, usually in the form of dissimilarity matrices. The use of suitable statistical tests in conjunction with those matrices typically provides us with all the necessary information to evaluate the overall similarity of groups of microbial communities. However, in some cases, this approach can lead us to deceptive conclusions, mainly due to the uneven dispersions of the groups and the existence of unique or unexpected substructures in the dataset. To address these issues, we developed divide and compare (DivCom), an automated tool for advanced beta diversity analysis. DivCom reveals the inner structure of groups by dividing their samples into the appropriate number of clusters and then compares the distances of every profile to the centers of these clusters. This information can be used for determining the existing interrelation of the groups. The proposed methodology and the developed tool were assessed by comparing the response of anemic patients with or without inflammatory bowel disease to different iron replacement therapies. DivCom generated results that revealed the inner structure of the dataset, evaluated the relationship among the clusters, and assessed the effect of the treatments. The DivCom tool is freely available at: https://github.com/Lagkouvardos/DivCom.

Iron Supplementation at the Crossroads of Nutrition and Gut Microbiota: The State of the Art

Gut microbiota has received significant attention owing to its decisive role in human health and disease. Diet exerts a significant influence on the variety and number of bacteria residing in the intestinal epithelium. On the other hand, as iron is a key micronutrient for blood formation and oxygen supply, its deficiency is highly prevalent worldwide. In fact, it is the most common cause of anemia and thus, iron supplementation is widespread. However, there is concern due to some potential risks linked to iron supplementation. Therefore, we have reviewed the available evidence of the effects that iron supplementation exerts on the gut microbiota as well as its potential benefits and risks. The compiled information suggests that iron supplementation is potentially harmful for gut microbiota. Therefore, it should be performed with caution, and by principle, recommended only to individuals with proven iron deficiency or iron-deficiency anemia to avoid potential adverse effects. In any case, large and long-term population studies are urgently needed to confirm or refute these results, mainly focused on vulnerable populations.

Gut microbial metabolome in inflammatory bowel disease: From association to therapeutic perspectives

Inflammatory bowel disease (IBD), comprising Crohn's disease (CD) and ulcerative colitis (UC), is a set of clinically chronic, relapsing gastrointestinal inflammatory disease and lacks of an absolute cure. Although the precise etiology is unknown, developments in high-throughput microbial genomic sequencing significantly illuminate the changes in the intestinal microbial structure and functions in patients with IBD. The application of microbial metabolomics suggests that the microbiota can influence IBD pathogenesis by producing metabolites, which are implicated as crucial mediators of host-microbial crosstalk. This review aims to elaborate the current knowledge of perturbations of the microbiome-metabolome interface in IBD with description of altered composition and metabolite profiles of gut microbiota. We emphasized and elaborated recent findings of several potentially protective metabolite classes in IBD, including fatty acids, amino acids and derivatives and bile acids. This article will facilitate a deeper understanding of the new therapeutic approach for IBD by applying metabolome-based adjunctive treatment.

Decreased serum iron concentration and total iron binding capacity are associated with serious Crohn's disease

This study aimed to investigate whether serum indicators related to iron stores in the body are associated with clinical and endoscopic disease severity. Eighty-four patients with Crohn’s disease (CD) and twenty-four healthy volunteers were included. The indicators related to iron stores were detected within one week after endoscopic and CT enterography examinations. Patients were divided into three groups according to the CDAI(Crohn's disease activity index)scores. Serum iron levels were decreased in all groups (p < 0.05), and the values of remission group were higher than those of moderate group (p < 0.001). The total iron binding capacity(TIBC)values of the moderate group were lower than those of the controls and the other groups (p < 0.05). None of the indicators differed significantly among the patients classified by SES-CD (p > 0.05). Underweight, decreased serum iron and TIBC were independent risk factors for moderate clinical disease. Combined detection of decreased serum iron and TIBC was helpful in differentiating severe patients. The sensitivity and specificity were 32.7% and 100%, respectively (AUC = 0.812, p < 0.01). Decreases in serum iron and TIBC were associated with the clinical activity of CD. Combined detection of the two indicators was conducive to screening serious disease.

Effect of oral and intraperitoneal administration of walnut-derived pentapeptide PW5 on cognitive impairments in APPSWE/PS1ΔE9 mice

Food-derived bioactive peptides, encrypted in native protein sequence, have attracted enormous research attention due to its potential in the prevention and/or treatment of a broad range of diseases. However, administration route poses a great challenge to their development and commercial applications. Patient-friendly delivery of bioactive peptides which also enhances its efficacy urgently remain to be addressed. Here we compared the effects of oral administration (PO) to intraperitoneal injection (IP) of a walnut-derived bioactive pentapeptide PW5 (Pro-Pro-Lys-Asn-Trp) in cognitive improvement capacity in APP_SWE/PS1_ΔE9 transgenic mice. Strikingly, we found that only PO administration of PW5 could effectively ameliorate cognitive impairments and reduce the β-amyloid deposits in the brain compared to the IP administration. This may be attributable to alterations in the gut microbiota communities, including alterations in microbial α- and β-diversities after PO treatment, leading to the reversal of the relative abundances of ten differential genera (e.g. Acinetobacter, Lactobacillus, Akkermansia, Allobaculum, Adlercreutzia, Coriobacteriaceae, unclassified_p_ Firmicutes, Desulfovibrionaceae, Oscillospira and Anaeroplasma) which are highly correlated with disease progression. Thus, this study has leveraged on PW5 to proof the superior efficacy of oral delivery to injection delivery in improving cognitive impairments in vivo, suggesting that oral delivery might be highly recommended as a prioritized delivery route in the development of food-derived peptides.

Effects of Hydrogen Sulfide on the Microbiome: From Toxicity to Therapy

Significance: Hydrogen sulfide (H2S), an important regulator of physiology and health, helps resolve inflammation and promotes tissue repair in the gastrointestinal tract. Recent Advances: Gut microbiota live as a multispecies biofilm in close interaction with the upper mucus layer lining the epithelium. The relative abundance, spatial organization, and function of these microorganisms affect a broad range of health outcomes. This article provides a state-of-the-art review of our understanding of the cross talk between H2S, the gut microbiota, and health. H2S can have toxic or therapeutic effects, depending on its concentration and source. When produced at excessive concentrations by local microbiota, H2S may cause mucus disruption and inflammation and contribute to development of cancer. In contrast, low levels of endogenous or exogenous H2S directly stabilize mucus layers, prevent fragmentation and adherence of the microbiota biofilm to the epithelium, inhibit the release of invasive pathobionts, and help resolve inflammation and tissue injury. Although scarce, research findings suggest that dietary H2S obtained from plants or ingestion of the H2S precursor, L-cysteine, may also modulate the abundance and function of microbiota. Critical Issues: A critical issue is the lack of understanding of the metagenomic, transcriptomic, and proteomic alterations that characterize the interactions between H2S and gut microbiota to shape health outcomes. Future Directions: The ambivalent roles of H2S in the gut offer a fertile ground for research on such critical issues. The findings will improve our understanding of how H2S modulates the microbiota to affect body function and will help identify novel therapeutic strategies. Antioxid. Redox Signal. 36, 211-219.

Melatonin Mitigates Oxazolone-Induced Colitis in Microbiota-Dependent Manner

Levels of type 2 cytokines are elevated in the blood and intestinal tissues of ulcerative colitis (UC) patients in the active phase; this phenomenon indicates the participation of type 2 immune response in UC progression. The beneficial effects of melatonin in dextran sodium sulfate (DSS) and 2,4,6-trinitrobenzene sulfonic acid (TNBS) colitis models have been illustrated, but its role in the oxazolone (Oxa)-induced colitis model (driven by type 2 immune response) remains relatively unknown. We investigated the relationship between melatonin concentration and the severity of UC, revealing a significantly negative correlation. Subsequently, we investigated the effects of melatonin in Oxa-induced colitis mice and the potential underlying mechanisms. Administration of melatonin significantly counteracted body weight loss, colon shortening, and neutrophil infiltration in Oxa-induced colitis mice. Melatonin treatment mitigated Oxa-induced colitis by suppressing type 2 immune response. In addition, melatonin attenuated intestinal permeability by enhancing the expression of ZO-1 and occludin in colitis mice. Interestingly, the protective effect of melatonin was abolished when the mice were co-housed, indicating that the regulation of gut microbiota by melatonin was critical in alleviating Oxa-induced colitis. Subsequently, 16S rRNA sequencing was performed to explore the microbiota composition. Decreased richness and diversity of intestinal microbiota at the operational taxonomic unit (OTU) level resulted from melatonin treatment. Melatonin also elevated the abundance of Bifidobacterium, a well-known probiotic, and reduced proportions of several harmful bacterial genera, such as Desulfovibrio, Peptococcaceae, and Lachnospiraceae. Fecal microbiota transplantation (FMT) was used to explore the role of microbiota in the function of melatonin in Oxa-induced colitis. Microbiota transplantation from melatonin-treated mice alleviated Oxa-induced colitis, suggesting that the microbiome participates in the relief of Oxa-induced colitis by melatonin. Our findings demonstrate that melatonin ameliorates Oxa-induced colitis in a microbiota-dependent manner, suggesting the therapeutic potential of melatonin in treating type 2 immunity-associated UC.

Saccharomyces boulardii alleviates DSS-induced intestinal barrier dysfunction and inflammation in humanized mice

Recent clinical studies have demonstrated a beneficial effect of Saccharomyces boulardii (S. boulardii) in inflammatory bowel disease (IBD). However, the underlying mechanisms remain poorly defined. In this study, we investigated the modulating effect of S. boulardii on the intestinal microbiota in humanized mice with dextran sulfate sodium (DSS)-induced colitis. The mice were fed an S. boulardii-supplement diet for 16 days before DSS treatment. The results showed that feeding S. boulardii significantly ameliorated the colon damage and regulated inflammatory responses by modulating the cytokine profile. These changes were found to be associated with an altered microbiome composition and short-chain fatty acid (SCFA) metabolism. Further analysis demonstrated that S. boulardii-derived polysaccharides and polypeptides promoted the growth of certain probiotics and increased the microbial metabolite SCFAs levels. Overall, these findings demonstrated the role of S. boulardii as a potential gut microbiota modulator to prevent and treat IBD.

The Communication Between Intestinal Microbiota and Ulcerative Colitis: An Exploration of Pathogenesis, Animal Models, and Potential Therapeutic Strategies

Ulcerative Colitis (UC) is a chronic inflammatory bowel disease. The prolonged course of UC and the lack of effective treatment management make it difficult to cure, affecting the health and life safety of patients. Although UC has received more attention, the etiology and pathogenesis of UC are still unclear. Therefore, it is urgent to establish an updated and comprehensive understanding of UC and explore effective treatment strategies. Notably, sufficient evidence shows that the intestinal microbiota plays an important role in the pathogenesis of UC, and the treating method aimed at improving the balance of the intestinal microbiota exhibits a therapeutic potential for UC. This article reviews the relationship between the genetic, immunological and microbial risk factors with UC. At the same time, the UC animal models related to intestinal microbiota dysbiosis induced by chemical drugs were evaluated. Finally, the potential value of the therapeutic strategies for restoring intestinal microbial homeostasis and treating UC were also investigated. Comprehensively, this study may help to carry out preclinical research, treatment theory and methods, and health management strategy of UC, and provide some theoretical basis for TCM in the treatment of UC.

Iron Deficiency in Heart Failure: Mechanisms and Pathophysiology

Iron is an essential micronutrient for a myriad of physiological processes in the body beyond erythropoiesis. Iron deficiency (ID) is a common comorbidity in patients with heart failure (HF), with a prevalence reaching up to 59% even in non-anaemic patients. ID impairs exercise capacity, reduces the quality of life, increases hospitalisation rate and mortality risk regardless of anaemia. Intravenously correcting ID has emerged as a promising treatment in HF as it has been shown to alleviate symptoms, improve quality of life and exercise capacity and reduce hospitalisations. However, the pathophysiology of ID in HF remains poorly characterised. Recognition of ID in HF triggered more research with the aim to explain how correcting ID improves HF status as well as the underlying causes of ID in the first place. In the past few years, significant progress has been made in understanding iron homeostasis by characterising the role of the iron-regulating hormone hepcidin, the effects of ID on skeletal and cardiac myocytes, kidneys and the immune system. In this review, we summarise the current knowledge and recent advances in the pathophysiology of ID in heart failure, the deleterious systemic and cellular consequences of ID.

Gut microbiome in hemodialysis patients treated with calcium acetate or treated with sucroferric oxyhydroxide: a pilot study

PURPOSE

It has been proved that the gut microbiome is altered in patients with chronic kidney disease. This contributes to chronic inflammation and increases cardiovascular risk and mortality, especially in those undergoing hemodialysis. Phosphate binders may potentially induce changes in their microbiome. This trial aimed to compare the changes in the gut microbiome of hemodialysis patients treated with calcium acetate to those treated with sucroferric oxyhydroxide.

METHODS

Twelve hemodialysis patients were distributed to receive calcium acetate or sucroferric oxyhydroxide for 5 months. Blood samples (for biochemical analysis) and stool samples (for microbiome analysis) were collected at baseline, 4, 12, and 20 weeks after treatment initiation. Fecal DNA was extracted and a 16S rRNA sequencing library was constructed targeting the V3 and V4 hypervariable regions.

RESULTS

Regarding clinical variables and laboratory parameters, no statistically significant differences were observed between calcium acetate or sucroferric oxyhydroxide groups. When analyzing stool samples, we found that all patients were different (p = 0.001) among themselves and these differences were kept along the 20 weeks of treatment. The clustering analysis in microbial profiles grouped the samples of the same patient independently of the treatment followed and the stage of the treatment.

CONCLUSION

These results suggest that a 5-month treatment with either calcium acetate or sucroferric oxyhydroxide did not modify baseline diversity or baseline bacterial composition in hemodialysis patients, also about the high-variability profiles of the gut microbiome found among these patients.

Lipidomics Reveals Serum Specific Lipid Alterations in Diabetic Nephropathy

In diabetes mellitus (DM), disorders of glucose and lipid metabolism are significant causes of the onset and progression of diabetic nephropathy (DN). However, the exact roles of specific lipid molecules in the pathogenesis of DN remain unclear. This study recruited 577 participants, including healthy controls (HCs), type-2 DM (2-DM) patients, and DN patients, from the clinic. Serum samples were collected under fasting conditions. Liquid chromatography-mass spectrometry-based lipidomics methods were used to explore the lipid changes in the serum and identify potential lipid biomarkers for the diagnosis of DN. Lipidomics revealed that the combination of lysophosphatidylethanolamine (LPE) (16:0) and triacylglycerol (TAG) 54:2-FA18:1 was a biomarker panel for predicting DN. The receiver operating characteristic analysis showed that the panel had a sensitivity of 89.1% and 73.4% with a specificity of 88.1% and 76.7% for discriminating patients with DN from HCs and 2-DM patients. Then, we divided the DN patients in the validation cohort into microalbuminuria (diabetic nephropathy at an early stage, DNE) and macroalbuminuria (diabetic nephropathy at an advanced stage, DNA) groups and found that LPE(16:0), phosphatidylethanolamine (PE) (16:0/20:2), and TAG54:2-FA18:1 were tightly associated with the stages of DN. The sensitivity of the biomarker panel to distinguish between patients with DNE and 2-DM, DNA, and DNE patients was 65.6% and 85.9%, and the specificity was 76.7% and 75.0%, respectively. Our experiment showed that the combination of LPE(16:0), PE(16:0/20:2), and TAG54:2-FA18:1 exhibits excellent performance in the diagnosis of DN.

Leveraging diet to engineer the gut microbiome

Autoimmune diseases, including inflammatory bowel disease, multiple sclerosis and rheumatoid arthritis, have distinct clinical presentations but share underlying patterns of gut microbiome perturbation and intestinal barrier dysfunction. Their potentially common microbial drivers advocate for treatment strategies aimed at restoring appropriate microbiome function, but individual variation in host factors makes a uniform approach unlikely. In this Perspective, we consolidate knowledge on diet-microbiome interactions in local inflammation, gut microbiota imbalance and host immune dysregulation. By understanding and incorporating the effects of individual dietary components on microbial metabolic output and host physiology, we examine the potential for diet-based therapies for autoimmune disease prevention and treatment. We also discuss tools targeting the gut microbiome, such as faecal microbiota transplantation, probiotics and orthogonal niche engineering, which could be optimized using custom dietary interventions. These approaches highlight paths towards leveraging diet for precise engineering of the gut microbiome at a time of increasing autoimmune disease.

What's metal got to do with it? Transition metals in Clostridioides difficile infection

The enteric pathogen Clostridioides difficile overcomes barriers to colonization imposed by the microbiota and host immune response to induce disease. To navigate the dynamic gut environment, C. difficile must respond to dietary and host-mediated fluctuations in transition metal availability. Transition metals are required trace nutrients that foster inter-microbial competition when limited, inhibit bacterial growth through host sequestration, or induce toxicity in excess. This review highlights recent evidence that transition metals influence multiple stages of C. difficile colonization and that C. difficile initiates a coordinated response to maintain metal-dependent homeostasis. Further exploration of the mechanisms of C. difficile metal sensing and nutrient competition with the microbiota will be necessary for the therapeutic manipulation of the gut environment during C. difficile infection.

Microbial profiles of peri-implant mucositis and peri-implantitis: Submucosal microbial dysbiosis correlates with disease severity

OBJECTIVE

To investigate the microbiome characteristics of peri-implant mucositis (PM) and peri-implantitis (PI), and to analyse the correlation between disease severity and submucosal microbial dysbiosis.

MATERIALS AND METHODS

A cross-sectional study design was conducted. Submucosal biofilm samples from 27 PM sites and 37 PI sites from 64 patients were collected and analysed using 16S rRNA gene sequencing (Illumina). Differences in microbiological profiles between PM and PI were evaluated using the α-diversity, β-diversity and linear discriminant analysis effect size (LEfSe) analysis. The relative abundances of the taxa at the phylum and genus levels were compared using the Wilcoxon rank test and logistic regression. The microbial dysbiosis index (MDI) was calculated, and its relationship with clinical measurements (probing depth, bleeding on probing and marginal bone loss, among others) was analysed using Pearson's correlation coefficient.

RESULTS

The overall microbiome distribution in the PM and PI sites was similar according to α- and β-diversity. Twenty-three taxa at the genus level and two taxa at the phylum level showed significant differences in relative abundance between the two clinical classifications. Five taxa at the genus level were screened out for the MDI calculation after logistic regression. No clinical measurements but marginal bone loss showed a significant positive correlation with microbial dysbiosis.

CONCLUSION

The microbiome richness, diversity and distribution were similar in PM and PI sites, including both common periodontal bacteria and novel species. In addition, an increase in marginal bone loss was significantly associated with submucosal microbial dysbiosis.

Iron Deficiency Anemia in Inflammatory Bowel Diseases-A Narrative Review

Inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis, is characterized by chronic inflammation of the gastrointestinal tract. IBD has been associated with numerous symptoms and complications, with the most common being iron deficiency anemia (IDA). Iron deficiency in IBD is caused by inadequate intake, malabsorption (including duodenal involvement and surgical removal), and chronic blood loss by mucosal ulcerations. Therefore, an appropriate diet should be enforced. Iron deficiency and iron supplementation have been associated with alterations to gut microbiota. IBD-associated anemia, in particular iron deficiency anemia, is associated with a significant decrease in quality of life and with clinical symptoms such as chronic fatigue, headaches and dizziness, reduced exercise tolerance, pale skin, nails, conjunctiva, and fainting. However, despite these numerous adverse symptoms, IDA remains undertreated. The European Crohn's and Colitis Organisation (ECCO) guidelines state that patients should be monitored for anemia. Adequate treatment, whether oral or intravenous, should be implemented while taking into consideration C-reactive protein values (CRP), hemoglobin levels, and therapeutic response. It should be stressed that every case of anemia in IBD patients should be treated. Intravenous iron formulations, which are more superior compared to the oral form, should be used. There is a need to increase awareness and implementation of international guidelines on iron supplementation in patients with IBD.

Impact of in-hospital intravenous iron supplementation on red blood cell transfusions: experience from an Internal Medicine Unit

BACKGROUND

Pharmacological treatment of iron deficiency anaemia can reduce red blood cell (RBC) transfusions. Intravenous iron provides a more effective and quicker correction of iron deficiency anaemia than oral iron, and third-generation high-dose intravenous iron formulations allow the complete correction of iron deficiency with just one or two drug infusions, thus facilitating iron supplementation therapy and reducing transfusion requirement.

MATERIAL AND METHODS

In an observational, retrospective study we compared RBC transfusion requirement during hospitalisation and within 3 months of hospital discharge in 88 patients with iron deficiency anaemia treated with high-dose ferric carboxymaltose and in 85 patients treated with ferric gluconate while hospitalised in the Internal Medicine unit of our Institution.

RESULTS

Ferric carboxymaltose reduced the number of RBC units given to each transfused patient during hospitalisation (1.81±0.84 vs 2.39±1.49, p=0.011). At hospital discharge, fewer ferric carboxymaltose patients were prescribed home therapy with iron. No differences between treatment groups were observed in the proportion of patients or the number of RBC units transfused within 3 months of discharge. At one month from discharge, however, only 2 ferric carboxymaltose patients had been transfused compared with 7 ferric gluconate patients (p=0.078). Patients transfused post-discharge were more likely to have an underlying malignancy and/or higher serum creatinine concentrations.

DISCUSSION

Treatment with ferric carboxymaltose reduced the number of RBC units per transfused patient. Larger studies are required to define risk factors associated with post-discharge transfusion requirement and to establish if home therapy with iron will reduce subsequent transfusions in patients treated with ferric carboxymaltose.

Emerging Pathological Engagement of Ferroptosis in Gut Diseases

Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, is mainly characterized by chronic and progressive inflammation that damages the gastrointestinal mucosa. Increasing studies have enlightened that dysregulated cell death occurs in the inflamed sites, leading to the disruption of the intestinal barrier and aggravating inflammatory response. Ferroptosis, a newly characterized form of regulated cell death, is driven by the lethal accumulation of lipid peroxides catalyzed by cellular free iron. It has been widely documented that the fundamental features of ferroptosis, including iron deposition, GSH exhaustion, GPX4 inactivation, and lipid peroxidation, are manifested in the injured gastrointestinal tract in IBD patients. Furthermore, manipulation of the critical ferroptotic genes could alter the progression, severity, or even morbidity of the experimental colitis. Herein, we critically summarize the recent advances in the field of ferroptosis, focusing on interpreting the potential engagement of ferroptosis in the pathogenesis of IBD. Moreover, we are attempting to shed light on a perspective insight into the possibility of targeting ferroptosis as novel therapeutic designs for the clinical intervention of these gastrointestinal diseases.

Physiology and Inflammation Driven Pathophysiology of Iron Homeostasis-Mechanistic Insights into Anemia of Inflammation and Its Treatment

Anemia is very common in patients with inflammatory disorders. Its prevalence is associated with severity of the underlying disease, and it negatively affects quality of life and cardio-vascular performance of patients. Anemia of inflammation (AI) is caused by disturbances of iron metabolism resulting in iron retention within macrophages, a reduced erythrocyte half-life, and cytokine mediated inhibition of erythropoietin function and erythroid progenitor cell differentiation. AI is mostly mild to moderate, normochromic and normocytic, and characterized by low circulating iron, but normal and increased levels of the storage protein ferritin and the iron hormone hepcidin. The primary therapeutic approach for AI is treatment of the underlying inflammatory disease which mostly results in normalization of hemoglobin levels over time unless other pathologies such as vitamin deficiencies, true iron deficiency on the basis of bleeding episodes, or renal insufficiency are present. If the underlying disease and/or anemia are not resolved, iron supplementation therapy and/or treatment with erythropoietin stimulating agents may be considered whereas blood transfusions are an emergency treatment for life-threatening anemia. New treatments with hepcidin-modifying strategies and stabilizers of hypoxia inducible factors emerge but their therapeutic efficacy for treatment of AI in ill patients needs to be evaluated in clinical trials.

Importance of Hepcidin in the Etiopathogenesis of Anemia in Inflammatory Bowel Disease

Anemia is the most common extraintestinal systemic complication of inflammatory bowel disease. Iron deficiency anemia and anemia of chronic disease are among the most frequent types. Intestinal iron absorption is controlled by the activity of ferroportin. Cells with high expression of ferroportin include enterocytes, and also macrophages and hepatocytes. Iron homeostasis is controlled by the hepcidin-ferroportin axis. Hepcidin is a central regulator of iron metabolism and can also serve as a marker of systemic inflammation. During systemic inflammatory response, the synthesis of hepcidin increases, and hepcidin binds to ferroportin and inhibits its activity. Thus, iron is not absorbed from the bowel into the circulation and also remains sequestered in macrophages. Conversely, hepcidin synthesis is suppressed during conditions requiring increased iron intake for enhanced erythropoiesis, such as iron deficiency anemia or hypoxia. Here, ferroportin is not blocked, and iron is actively absorbed into the bloodstream and also released from the stores. Production of hepcidin is influenced by the status of total body iron stores, systemic inflammatory activity and erythropoietic activity. Oral iron therapy is limited in inflammatory bowel diseases due to ongoing gastrointestinal inflammation. It is less effective and may worsen the underlying disease. Therefore, the choice between oral and parenteral iron therapy must be made with caution. Oral iron would be ineffective at high hepcidin levels due to concurrent ferroportin blockage. Contrarily, low levels of hepcidin indicate that oral iron therapy should be successful. An understanding of hepcidin can help in understanding the body's reaction to iron depletion during the inflammatory process.

The influence of the gut microbiome on BCG-induced trained immunity

BACKGROUND

The bacillus Calmette-Guérin (BCG) vaccine protects against tuberculosis and heterologous infections but elicits high inter-individual variation in specific and nonspecific, or trained, immune responses. While the gut microbiome is increasingly recognized as an important modulator of vaccine responses and immunity in general, its potential role in BCG-induced protection is largely unknown.

RESULTS

Stool and blood were collected from 321 healthy adults before BCG vaccination, followed by blood sampling after 2 weeks and 3 months. Metagenomics based on de novo genome assembly reveals 43 immunomodulatory taxa. The nonspecific, trained immune response is detected by altered production of cytokines IL-6, IL-1β, and TNF-α upon ex vivo blood restimulation with Staphylococcus aureus and negatively correlates with abundance of Roseburia. The specific response, measured by IFN-γ production upon Mycobacterium tuberculosis stimulation, is associated positively with Ruminococcus and Eggerthella lenta. The identified immunomodulatory taxa also have the strongest effects on circulating metabolites, with Roseburia affecting phenylalanine metabolism. This is corroborated by abundances of relevant enzymes, suggesting alternate phenylalanine metabolism modules are activated in a Roseburia species-dependent manner.

CONCLUSIONS

Variability in cytokine production after BCG vaccination is associated with the abundance of microbial genomes, which in turn affect or produce metabolites in circulation. Roseburia is found to alter both trained immune responses and phenylalanine metabolism, revealing microbes and microbial products that may alter BCG-induced immunity. Together, our findings contribute to the understanding of specific and trained immune responses after BCG vaccination.

IBD metabonomics predicts phenotype, disease course, and treatment response

Metabonomics in inflammatory bowel disease (IBD) characterizes the effector molecules of biological systems and thus aims to describe the molecular phenotype, generate insight into the pathology, and predict disease course and response to treatment. Nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry (MS), and integrated NMR and MS platforms coupled with multivariate analyses have been applied to create such metabolic profiles. Recent advances have identified quiescent ulcerative colitis as a distinct molecular phenotype and demonstrated metabonomics as a promising clinical tool for predicting relapse and response to treatment with biologics as well as fecal microbiome transplantation, thus facilitating much needed precision medicine. However, understanding this complex research field and how it translates into clinical settings is a challenge. This review aims to describe the current workflow, analytical strategies, and associated bioinformatics, and translate current IBD metabonomic knowledge into new potential clinically applicable treatment strategies, and outline future key translational perspectives.

Utilizing machine learning with knockoff filtering to extract significant metabolites in Crohn's disease with a publicly available untargeted metabolomics dataset

Metabolomic data processing pipelines have been improving in recent years, allowing for greater feature extraction and identification. Lately, machine learning and robust statistical techniques to control false discoveries are being incorporated into metabolomic data analysis. In this paper, we introduce one such recently developed technique called aggregate knockoff filtering to untargeted metabolomic analysis. When applied to a publicly available dataset, aggregate knockoff filtering combined with typical p-value filtering improves the number of significantly changing metabolites by 25% when compared to conventional untargeted metabolomic data processing. By using this method, features that would normally not be extracted under standard processing would be brought to researchers' attention for further analysis.

Iron Deficiency Anemia in Inflammatory Bowel Disease: What Do We Know?

One of the most common extraintestinal manifestations of inflammatory bowel disease is iron deficiency anemia. It is often an untreated condition that significantly impairs patients' quality of life and elevates mortality and morbidity. Although it is often accompanied by mild symptoms (e.g., fatigue, lethargy), it can provoke severe health conditions, such as dyspnea, palpitation, angina, and mental disorders, and increases hospitalization and mortality rate as well. As anemia develops through several pathomechanisms, such as occult bleeding, chronic inflammation, and medicines (e.g., methotrexate), treating anemia effectively requires to manage the underlying pathological changes as well. Based on international publications and data, it is a frequent condition and more frequent in pediatrics. According to Goodhand et al., iron deficiency is present in more than 60% of children, whereas only 14% of them received oral iron therapy. Compared to adult patients, 22% have iron deficiency, and 48% of them received oral and 41% intravenous iron therapy. Miller et al. also highlighted that among young patients iron deficiency anemia is a frequent condition, as almost 50% of the patients were anemic in their cohort. European Crohn's and Colitis Organisation's statements are clear regarding the diagnosis of iron deficiency anemia, and the iron supplementation as well. Third-generation parenteral iron supplementations seem to be safer and more effective than oral iron pills. Oral iron in many cases cannot replace the iron homeostasis as well; furthermore, it can provoke dysbiosis, which can potentially lead to relapse. As a result, we claim that both oral and parenteral should be used more frequently; furthermore, intravenous iron could replace oral medicines as well in certain cases. Despite the fact that iron deficiency anemia is examined by many aspects, further questions can be raised. Can it imply underlying pathological lesions? Are both oral and intravenous iron therapy safe and effective? When and how are they used? We demand that more studies should be conducted regarding these issues.

Ferric carboxymaltose treatment for iron deficiency anemia in children with inflammatory bowel disease: Efficacy and risk of hypophosphatemia

BACKGROUND

Although intravenous ferric carboxymaltose (FCM) is effective in treating iron deficiency anemia (IDA) in paediatric inflammatory bowel disease (pIBD), no data are available on its post-infusion related risks.

AIMS

We assessed the efficacy of FCM and the rate of post-infusion hypophosphatemia in a large cohort of children with IBD and IDA.

METHODS

All children with IBD with IDA treated with FCM over 5-year period were reviewed. Disease activity, biohumoral assessment and treatments were evaluated at baseline, 4-6 and 12 weeks after each infusion.

RESULTS

128 patients [median age at first infusion: 13 years] were identified, 81 (63.3%) were <14 years, 10 (7.8%) <6 years. Eighty-three children (64.8%) received one infusion, whilst 45 (35.2%) repeated infusions. A significant increase in Hb (p<0.001), iron (p<0.001) and ferritin (p<0.001) was observed 4-6 and 12 weeks post-infusion. Hb gain was unrelated to disease severity. Low baseline iron was the main predicting factor for repeated infusions (p<0.05). Three patients reported infusion reactions, none <6 years. Twenty-five children had low post-infusion serum phosphate (11 were <14 years, 3 <6 years). Two children developed severe hypophosphatemia.

CONCLUSIONS

FCM administration is effective for IDA management in pIBD, including children <6 years. Due to the high prevalence of post-infusion hypophosphatemia, serum phosphate monitoring should be mandatory.

Oral Ferric Maltol Does Not Adversely Affect the Intestinal Microbiome of Patients or Mice, But Ferrous Sulphate Does

BACKGROUND AND AIMS

Altering dietary ferrous sulphate (FS) consumption exacerbates a murine model of colitis and alters the intestinal microbiome. We investigated the impact of oral ferric maltol (FM) and FS on mice with dextran sodium sulphate (DSS) induced colitis, and the microbiome of patients with iron deficiency.

METHODS

Mice had acute colitis induced, with 2% DSS for 5 days, followed by water. During this period, groups of mice were fed standard chow (200 ppm iron, SC, n = 8), or SC with 200ppm FS supplementation (n = 16, FSS), or SC with 200 ppm FM supplementation (n = 16, FMS). Clinical, pathological and microbiome assessments were compared at days 1 and 10. Fecal bacterial gDNA was extracted and the microbiome assessed by sequencing. Statistical inferences were made using MacQIIME. Principal Coordinates Analysis were used to visualize beta-diversity cluster analysis. Ten patients with IDA were treated with FS, and six with inactive inflammatory bowel disease received FM, supplements for four weeks: pre- and mid-treatment fecal samples were collected: the microbiome was assessed (see above).

RESULTS

In mice, after DSS treatment, there was a decrease in many genera in the SC and FSS groups: Lactobacillales increased in mice that received FMS. In humans, FS treatment led to an increase in five genera, but FM was not associated with any measurable change. The severity of DSS-induced colitis was greater with FSS than FMS.

CONCLUSIONS

This study demonstrates differential and unique influences of ferric maltol and ferrous sulphate supplements on intestinal microbiota. These differences might contribute to the different side effects associated with these preparations.

Bioaccessibility and Bioavailability of Minerals in Relation to a Healthy Gut Microbiome

Adequate amounts of a wide range of micronutrients are needed by body tissues to maintain health. Dietary intake must be sufficient to meet these micronutrient requirements. Mineral deficiency does not seem to be the result of a physically active life or of athletic training but is more likely to arise from disturbances in the quality and quantity of ingested food. The lack of some minerals in the body appears to be symbolic of the modern era reflecting either the excessive intake of empty calories or a negative energy balance from drastic weight-loss diets. Several animal studies provide convincing evidence for an association between dietary micronutrient availability and microbial composition in the gut. However, the influence of human gut microbiota on the bioaccessibility and bioavailability of trace elements in human food has rarely been studied. Bacteria play a role by effecting mineral bioavailability and bioaccessibility, which are further increased through the fermentation of cereals and the soaking and germination of crops. Moreover, probiotics have a positive effect on iron, calcium, selenium, and zinc in relation to gut microbiome composition and metabolism. The current literature reveals the beneficial effects of bacteria on mineral bioaccessibility and bioavailability in supporting both the human gut microbiome and overall health. This review focuses on interactions between the gut microbiota and several minerals in sport nutrition, as related to a physically active lifestyle.

Role of Iron in the Molecular Pathogenesis of Diseases and Therapeutic Opportunities

Iron is an essential mineral that serves as a prosthetic group for a variety of proteins involved in vital cellular processes. The iron economy within humans is highly conserved in that there is no proper iron excretion pathway. Therefore, iron homeostasis is highly evolved to coordinate iron acquisition, storage, transport, and recycling efficiently. A disturbance in this state can result in excess iron burden in which an ensuing iron-mediated generation of reactive oxygen species imparts widespread oxidative damage to proteins, lipids, and DNA. On the contrary, problems in iron deficiency either due to genetic or nutritional causes can lead to a number of iron deficiency disorders. Iron chelation strategies have been in the works since the early 1900s, and they still remain the most viable therapeutic approach to mitigate the toxic side effects of excess iron. Intense investigations on improving the efficacy of chelation strategies while being well tolerated and accepted by patients have been a particular focus for many researchers over the past 30 years. Moreover, recent advances in our understanding on the role of iron in the pathogenesis of different diseases (both in iron overload and iron deficiency conditions) motivate the need to develop new therapeutics. We summarized recent investigations into the role of iron in health and disease conditions, iron chelation, and iron delivery strategies. Information regarding small molecule as well as macromolecular approaches and how they are employed within different disease pathogenesis such as primary and secondary iron overload diseases, cancer, diabetes, neurodegenerative diseases, infections, and in iron deficiency is provided.

Evaluation of the Cost-Effectiveness of Iron Formulations for the Treatment of Iron Deficiency Anaemia in Patients with Inflammatory Bowel Disease in the UK

Introduction

In patients with inflammatory bowel disease (IBD), iron deficiency anaemia (IDA) can impair quality of life and increase healthcare costs. Treatment options for IDA-associated IBD include oral iron and intravenous iron formulations (such as ferric carboxymaltose [FCM], ferric derisomaltose [FD, previously known as iron isomaltoside 1000], and iron sucrose [IS]). The present analysis compared the cost-effectiveness of FCM versus FD, IS, and oral iron sulfate in terms of additional cost per additional responder in the UK setting.

Methods

Cost-effectiveness was calculated for FCM versus FD, IS, and oral iron individually in terms of the additional cost per additional responder, defined as haemoglobin normalisation or an increase of ≥2 g/dL in haemoglobin levels, in a model developed in Microsoft Excel. Relative efficacy inputs were taken from a previously published network meta-analysis, since there is currently no single head-to-head trial evidence comparing all therapy options. Costs were calculated in 2020 pounds sterling (GBP) capturing the costs of iron preparations, healthcare professional time, and consumables.

Results

The analysis suggested that FCM may be the most effective intervention, with 81% of patients achieving a response. Response rates with FD, IS, and oral iron were 74%, 75%, and 69%, respectively. Total costs with FCM, FD, IS, and oral iron were GBP 296, GBP 312, GBP 503, and GBP 56, respectively. FCM was found to be more effective and less costly than both FD and IS, and therefore was considered dominant. Compared with oral iron, FCM was associated with an incremental cost-effectiveness ratio of GBP 2045 per additional responder.

Conclusions

FCM is likely to be the least costly and most effective IV iron therapy in the UK setting. Compared with oral iron, healthcare payers must decide whether the superior treatment efficacy of FCM is worth the additional cost.

The role of fecal sulfur metabolome in inflammatory bowel diseases

Sulfur metabolism and sulfur-containing metabolites play an important role in the human digestive system, and sulfur compounds and pathways are associated with inflammatory bowel diseases (IBD). In fact, cysteine metabolism results in the production of taurine and sulfate, and gut microbes catabolize them into hydrogen sulfide, a signaling molecule with various biological functions. Besides metabolites originating from sulfur metabolism, several other sulfur-containing metabolites of different classes were detected in human feces, consisting of non-volatile and volatile compounds. Sulfated steroids and bile acids such as taurine-conjugated bile acids are the major classes along with sulfur amino acids and sulfur-containing peptides. Indeed, sulfur-containing metabolites were described in stool samples from healthy subjects, patients suffering from colorectal cancer or IBD. In metabolomics-driven studies, around 50 known sulfur-containing metabolites were linked to IBD. Taurine, taurocholic acid, taurochenodeoxycholic acid, methionine, methanethiol and hydrogen sulfide were regularly reported in IBD studies, and most of them were elevated in stool samples from IBD patients. We summarized from this review that there is strong interplay between perturbed gut microbiota in IBD, and the consistently higher abundance of sulfur-containing metabolites, which potentially represent substrates for sulfidogenic bacteria such as Bilophila or Escherichia and promote their growth. These bacteria might shift their metabolism towards the degradation of taurine and cysteine and therefore to a higher hydrogen sulfide production.