Iron deficiency anemia-related gut microbiota dysbiosis in infants and young children: A pilot study

Influence of supplementation with iron and probiotic bacteria Lactobacillus plantarum and Lactobacillus curvatus on selected parameters of inflammatory state in rats on a high-fat iron-deficient diet

BACKGROUND

A high-fat (HF) diet, diet iron deficiency and iron supplementation may affect inflammatory parameters. Probiotics influence both iron metabolism and inflammation. We compared the inflammatory state in rats on a HF iron-deficient diet receiving oral iron, Lactobacillus plantarum and Lactobacillus curvatus in different combinations.

METHODS

This was a two-stage experiment. In groups C (n = 8) and HF (n = 8), rats ate a control or HF diet, respectively, for 16 weeks. In the group HFDEF (n = 48), rats ate a HF iron-deficient diet for 8 weeks (first stage) and were subsequently divided into 6 groups (n = 8 each) receiving the following for a further 8 weeks (second stage): HFDEF - a HF iron-deficient diet; HFDEFFe - a HF iron-deficient diet with iron; HFDEFLp and HFDEFLc - a HF iron-deficient diet with L. plantarum or L. curvatus, respectively; and HFDEFFeLp and HFDEFFeLc - a HF iron-deficient diet with iron and L. plantarum or L. curvatus, respectively. Body composition analysis and blood sampling was performed. Markers of iron status and levels of total antioxidant status (TAS), C-reactive protein (CRP), tumour necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) were measured in the blood.

RESULTS

TAS was higher in the HFDEF group (756.57 ± 489.53 ng mL-1) versus the HFDEFLc group (187.04 ± 47.84 ng mL-1; P = 0.022). No more differences were found between groups, or in TAS, CRP, TNF-α and IL-6 concentrations. Also, no differences were found between groups for alanine and aspartate aminotransferases, glucose, total cholesterol, low- and high-density lipoproteins and triglycerides. TAS level was positively correlated with ferritin concentration, IL-6 with TAS and TNF-α with hepcidin level.

CONCLUSIONS

Supplementation with L. plantarum, L. curvatus and iron in combinations exerts no influence on inflammatory status, lipid profile, hepatic function and serum fasting glucose in rats on a HF iron-deficient diet. © 2024 Society of Chemical Industry.

Intestinal microbiota composition and efficacy of iron supplementation in Peruvian children

OBJECTIVE

Despite repeated public health interventions, anemia prevalence among children remains a concern. We use an evolutionary medicine perspective to examine the intestinal microbiome as a pathway underlying the efficacy of iron-sulfate treatment. This study explores whether gut microbiota composition differs between anemic children who respond and do not respond to treatment at baseline and posttreatment and if specific microbiota taxa remain associated with response to iron supplementation after controlling for relevant inflammatory and pathogenic variables.

METHODS

Data come from 49 pre-school-aged anemic children living in San Juan de Lurigancho, Lima, Peru. We tested for differences in alpha and beta diversity using QIIME 2 and performed differential abundance testing in DESeq2 in R. We ran multivariate regression models to assess associations between abundance of specific taxa and response while controlling for relevant variables in Stata 17.

RESULTS

While we found no evidence for gut microbiota diversity associated with child response to iron treatment, we observed several differential abundance patterns between responders and non-responders at both timepoints. Additionally, we present support for a nonzero relationship between lower relative abundance of Barnesiellaceae and response to iron supplementation in samples collected before and after treatment.

CONCLUSION

While larger studies and more specific approaches are needed to understand the relationship between microbes and anemia in an epidemiological context, this study suggests that investigating nutritional status and pathogen exposure is key to better understanding the gut microbiome and impact of iron fortification.

Nutrition in chronic inflammatory conditions: Bypassing the mucosal block for micronutrients

Nutritional Immunity is one of the most ancient innate immune responses, during which the body can restrict nutrients availability to pathogens and restricts their uptake by the gut mucosa (mucosal block). Though this can be a beneficial strategy during infection, it also is associated with non-communicable diseases-where the pathogen is missing; leading to increased morbidity and mortality as micronutritional uptake and distribution in the body is hindered. Here, we discuss the acute immune response in respect to nutrients, the opposing nutritional demands of regulatory and inflammatory cells and particularly focus on some nutrients linked with inflammation such as iron, vitamins A, Bs, C, and other antioxidants. We propose that while the absorption of certain micronutrients is hindered during inflammation, the dietary lymph path remains available. As such, several clinical trials investigated the role of the lymphatic system during protein absorption, following a ketogenic diet and an increased intake of antioxidants, vitamins, and minerals, in reducing inflammation and ameliorating disease.

Cascade of atopic dermatitis comorbidities in children after birth for 15 years

BACKGROUND

Individuals with atopic dermatitis often develop other conditions.

OBJECTIVE

This study aimed to determine how atopic dermatitis comorbidities develop in children over time.

METHODS

This population-based administrative cohort study used national health insurance data. We traced individuals born in Korea between 2002 and 2003 to 2018. The date of initial atopic dermatitis diagnosis was set as the index date. Fifty-three childhood comorbidities of atopic dermatitis were identified as outcomes of interest by performing a comprehensive literature search and comparing the prevalence of diagnostic codes in children with and without atopic dermatitis. Four control children per individual in the atopic dermatitis group were randomly matched based on sex and index date. The association between atopic dermatitis and the development of each specified disease was assessed using proportional hazard assumption, followed by mapping of the temporal sequences of interconnected comorbidities.

RESULTS

The atopic dermatitis and control groups contained 67,632 and 270,528 individuals, respectively. The median age at the index date was 10 months, whereas the median follow-up period was 15 years. Twenty diseases that were associated with a higher risk of atopic dermatitis were identified and a chain of interconnected conditions created. The progression began in childhood with febrile seizures, constipation, and asthma, and was later associated with the emergence of food allergy, allergic rhinitis, psychiatric disorders, and autoimmune diseases.

CONCLUSION

Our study highlights the temporal nature of atopic dermatitis comorbidities in children, and indicates that an understanding of the comorbidities may inform its clinical management and treatment.

Washed microbiota transplantation improves haemoglobin levels in anaemia of chronic disease

BACKGROUND

Anaemia of chronic disease (ACD) is the second most common type of anaemia and lacks an effective treatment. Patients with anaemia are reported to have altered gut microbial profiles, which may affect erythropoiesis. Here, we investigated the gut microbial features of patients with ACD and determined whether regulating gut microbiota using washed microbiota transplantation (WMT) was effective in treating ACD.

METHODS

We compared the gut microbiota profile of patients with ACD and healthy controls, evaluated the efficacy of WMT on haematological parameters in the patients, and analysed the alterations in gut microbiota after WMT treatment.

RESULTS

Patients with ACD had lower gut microbial richness, and differences in microbial composition and function, relative to healthy controls. Additionally, the relative abundances of two butyrate-producing genera Lachnospiraceae NK4A136 group and Butyricicoccus, were positively correlated with the haemoglobin (HGB) level and lower in patients with ACD than controls. WMT significantly increased HGB levels in patients with ACD. After the first, second and third WMT rounds, normal HGB levels were restored in 27.02%, 27.78% and 36.37% (all p < .05) of patients with ACD, respectively. Moreover, WMT significantly increased the abundance of butyrate-producing genera and downregulated gut microbial functions that were upregulated in patients with ACD.

CONCLUSIONS

Patients with ACD exhibited differences in gut microbial composition and function relative to healthy controls. WMT is an effective treatment for ACD that reshapes gut microbial composition, restores butyrate-producing bacteria and regulates the functions of gut microbiota.

Biology of Anemia: A Public Health Perspective

Our goal is to present recent progress in understanding the biological mechanisms underlying anemia from a public health perspective. We describe important advances in understanding common causes of anemia and their interactions, including iron deficiency (ID), lack of other micronutrients, infection, inflammation, and genetic conditions. ID develops if the iron circulating in the blood cannot provide the amounts required for red blood cell production and tissue needs. ID anemia develops as iron-limited red blood cell production fails to maintain the hemoglobin concentration above the threshold used to define anemia. Globally, absolute ID (absent or reduced body iron stores that do not meet the need for iron of an individual but may respond to iron supplementation) contributes to only a limited proportion of anemia. Functional ID (adequate or increased iron stores that cannot meet the need for iron because of the effects of infection or inflammation and does not respond to iron supplementation) is frequently responsible for anemia in low- and middle-income countries. Absolute and functional ID may coexist. We highlight continued improvement in understanding the roles of infections and inflammation in causing a large proportion of anemia. Deficiencies of nutrients other than iron are less common but important in some settings. The importance of genetic conditions as causes of anemia depends upon the specific inherited red blood cell abnormalities and their prevalence in the settings examined. From a public health perspective, each setting has a distinctive composition of components underlying the common causes of anemia. We emphasize the coincidence between regions with a high prevalence of anemia attributed to ID (both absolute and functional), those with endemic infections, and those with widespread genetic conditions affecting red blood cells, especially in sub-Saharan Africa and regions in Asia and Oceania.

Predictive association of gut microbiome and NLR in anemic low middle-income population of Odisha- a cross-sectional study

Background

Iron is abundant on earth but not readily available for colonizing bacteria due to its low solubility in the human body. Hosts and microbiota compete fiercely for iron. <15% Supplemented Iron is absorbed in the small bowel, and the remaining iron is a source of dysbiosis. The gut microbiome signatures to the level of predicting anemia among low-middle-income populations are unknown. The present study was conducted to identify gut microbiome signatures that have predictive potential in association with Neutrophil to lymphocytes ratio (NLR) and Mean corpuscular volume (MCV) in anemia.

Methods

One hundred and four participants between 10 and 70 years were recruited from Odisha's Low Middle-Income (LMI) rural population. Hematological parameters such as Hemoglobin (HGB), NLR, and MCV were measured, and NLR was categorized using percentiles. The microbiome signatures were analyzed from 61 anemic and 43 non-anemic participants using 16 s rRNA sequencing, followed by the Bioinformatics analysis performed to identify the diversity, correlations, and indicator species. The Multi-Layered Perceptron Neural Network (MLPNN) model were applied to predict anemia.

Results

Significant microbiome diversity among anemic participants was observed between the lower, middle, and upper Quartile NLR groups. For anemic participants with NLR in the lower quartile, alpha indices indicated bacterial overgrowth, and consistently, we identified R. faecis and B. uniformis were predominating. Using ROC analysis, R. faecis had better distinction (AUC = 0.803) to predict anemia with lower NLR. In contrast, E. biforme and H. parainfluenzae were indicators of the NLR in the middle and upper quartile, respectively. While in Non-anemic participants with low MCV, the bacterial alteration was inversely related to gender. Furthermore, our Multi-Layered Perceptron Neural Network (MLPNN) models also provided 89% accuracy in predicting Anemic or Non-Anemic from the top 20 OTUs, HGB level, NLR, MCV, and indicator species.

Conclusion

These findings strongly associate anemic hematological parameters and microbiome. Such predictive association between the gut microbiome and NLR could be further evaluated and utilized to design precision nutrition models and to predict Iron supplementation and dietary intervention responses in both community and clinical settings.

Relationships of the gut microbiome with cognitive development among healthy school-age children

Background

The gut microbiome might play a role in neurodevelopment, however, evidence remains elusive. We aimed to examine the relationship between the intestinal microbiome and cognitive development of school-age children.

Methods

This cross-sectional study included healthy Israeli Arab children from different socioeconomic status (SES). The microbiome was characterized in fecal samples by implementing 16S rRNA gene sequencing. Cognitive function was measured using Stanford-Binet test, yielding full-scale Intelligence Quotient (FSIQ) score. Sociodemographics and anthropometric and hemoglobin measurements were obtained. Multivariate models were implemented to assess adjusted associations between the gut microbiome and FSIQ score, while controlling for age, sex, SES, physical growth, and hemoglobin levels.

Results

Overall, 165 children (41.2% females) aged 6-9 years were enrolled. SES score was strongly related to both FSIQ score and the gut microbiome. Measures of α-diversity were significantly associated with FSIQ score, demonstrating a more diverse, even, and rich microbiome with increased FSIQ score. Significant differences in fecal bacterial composition were found; FSIQ score explained the highest variance in bacterial β-diversity, followed by SES score. Several taxonomic differences were significantly associated with FSIQ score, including Prevotella, Dialister, Sutterella, Ruminococcus callidus, and Bacteroides uniformis.

Conclusions

We demonstrated significant independent associations between the gut microbiome and cognitive development in school-age children.

Characterization of Gut Microbiota Compositions along the Intestinal Tract in CD163/pAPN Double Knockout Piglets and Their Potential Roles in Iron Absorption

The gut microbiota is known to play a role in regulating host metabolism, yet the mechanisms underlying this regulation are not well elucidated. Our study aimed to characterize the differences in gut microbiota compositions and their roles in iron absorption between wild-type (WT) and CD163/pAPN double-gene-knockout (DKO) weaned piglets. A total of 58 samples along the entire digestive tract were analyzed for microbial community using 16S rRNA gene sequencing. The colonic microbiota and their metabolites were determined by metagenomic sequencing and untargeted liquid chromatography-mass spectrometry (LC-MS), respectively. Our results showed that no alterations in microbial community structure and composition were observed between DKO and WT weaned piglets, with the exception of colonic microbiota. Interestingly, the DKO piglets had selectively increased the relative abundance of the Leeia genus belonging to the Neisseriaceae family and decreased the Ruminococcaceae_UCG_014 genus abundance. Functional capacity analysis showed that organic acid metabolism was enriched in the colon in DKO piglets. In addition, the DKO piglets showed increased iron levels in important tissues compared with WT piglets without any pathological changes. Pearson's correlation coefficient indicated that the specific bacteria such as Leeia and Ruminococcaceae_UCG_014 genus played a key role in host iron absorption. Moreover, the iron levels had significantly (P < 0.05) positive correlation with microbial metabolites, particularly carboxylic acids and their derivatives, which might increase iron absorption by preventing iron precipitation. Overall, this study reveals an interaction between colonic microbiota and host metabolism and has potential significance for alleviating piglet iron deficiency. IMPORTANCE Iron deficiency is a major risk factor for iron deficiency anemia, which is among the most common nutritional disorders in piglets. However, it remains unclear how the gut microbiota interacts with host iron absorption. The current report provides the first insight into iron absorption-microbiome connection in CD163/pAPN double knockout piglets. The present results showed that carboxylic acids and their derivatives contributed to the absorption of nonheme iron by preventing ferric iron precipitation.

The Effects of Iron Deficiency on the Gut Microbiota in Women of Childbearing Age

Iron deficiency anemia (IDA) is the most prevalent and common nutritional deficiency worldwide and is a global health problem with significant risk, particularly among women of reproductive age. Oral iron supplementation is the most widely used and cost-effective treatment for iron deficiency and IDA. However, there are limitations regarding side effects such as enteritis, treatment compliance, and bioavailability. Intestinal microbiome characteristic research has been recently conducted to overcome these issues, but more is needed. Against this background, a metagenomics study on the 16S gene in the feces of young women vulnerable to IDA was conducted. As a result of analyzing 16 normal subjects and 15 IDA patients, significant differences in bacterial community distribution were identified. In particular, a significant decrease in Faecalibacterium was characteristic in IDA patients compared with normal subjects. Furthermore, in the case of patients who recovered from IDA following iron supplementation treatment, it was confirmed that Faecalibacterium significantly recovered to normal levels. However, no significance in beta diversity was seen compared with before treatment. There were also no differences in the beta diversity results between the recovered and normal subjects. Therefore, intestinal dysbiosis during the disease state was considered to be restored as IDA improved. Although the results were derived from a limited number of subjects and additional research is needed, the results of this study are expected to be the basis for developing treatment and prevention strategies based on host-microbiome crosstalk in IDA.

Intestinal Microbiota in Children with Anemia in Southern Peru through Next-Generation Sequencing Technology

Knowledge of the sequencing of the 16S rRNA gene constitutes a true revolution in understanding the composition of the intestinal microbiota and its implication in health states. This study details microbial composition through next-generation sequencing (NGS) technology in children with anemia. Anemia is the most frequent hematological disorder that affects human beings. In Peru, it is one of the conditions that presents the most significant concern due to the adverse effects that cause it, such as delayed growth and psychomotor development, in addition to a deficiency in cognitive development.

Effects of iron deficiency and iron supplementation at the host-microbiota interface: Could a piglet model unravel complexities of the underlying mechanisms?

Iron deficiency is the most prevalent human micronutrient deficiency, disrupting the physiological development of millions of infants and children. Oral iron supplementation is used to address iron-deficiency anemia and reduce associated stunting but can promote infection risk since restriction of iron availability serves as an innate immune mechanism against invading pathogens. Raised iron availability is associated with an increase in enteric pathogens, especially Enterobacteriaceae species, accompanied by reductions in beneficial bacteria such as Bifidobacteria and lactobacilli and may skew the pattern of gut microbiota development. Since the gut microbiota is the primary driver of immune development, deviations from normal patterns of bacterial succession in early life can have long-term implications for immune functionality. There is a paucity of knowledge regarding how both iron deficiency and luminal iron availability affect gut microbiota development, or the subsequent impact on immunity, which are likely to be contributors to the increased risk of infection. Piglets are naturally iron deficient. This is largely due to their low iron endowments at birth (primarily due to large litter sizes), and their rapid growth combined with the low iron levels in sow milk. Thus, piglets consistently become iron deficient within days of birth which rapidly progresses to anemia in the absence of iron supplementation. Moreover, like humans, pigs are omnivorous and share many characteristics of human gut physiology, microbiota and immunity. In addition, their precocial nature permits early maternal separation, individual housing, and tight control of nutritional intake. Here, we highlight the advantages of piglets as valuable and highly relevant models for human infants in promoting understanding of how early iron status impacts physiological development. We also indicate how piglets offer potential to unravel the complexities of microbiota-immune responses during iron deficiency and in response to iron supplementation, and the link between these and increased risk of infectious disease.

Gut microbiota: Linking nutrition and perinatal depression

Perinatal depression is a mood disorder that is reported in women during pregnancy (prenatal) and after childbirth (postnatal). The onset of perinatal depression is associated with changes in reproductive hormones, stress hormones and neurosteroids. These chemical compounds can be modulated by the gut microbiota, which may affect maternal mental health during the perinatal period via the gut-brain-axis. Recent studies suggest that nutritional and dietary interventions (vitamin D, ω-3 fatty acids, iron, and fiber) effectively prevent or mitigate maternal depression and anxiety, but their efficacy is confounded by various factors, including the gut microbiota. Probiotics are efficacious in maintaining microbiota homeostasis, and thus, have the potential to modulate the development of perinatal mood disorders, despite no evidence in human. Therefore, clinical trials are warranted to investigate the role of probiotic supplementation in perinatal depression and behavioral changes. This article reviews the interplay between nutrition, gut microbiota and mood and cognition, and the evidence suggesting that probiotics affect the onset and development of perinatal depression.

Oral Lactoferrin Supplementation during Induction Chemotherapy Promotes Gut Microbiome Eubiosis in Pediatric Patients with Hematologic Malignancies

Induction chemotherapy is the first-line treatment for pediatric patients with hematologic malignancies. However, several complications may arise, mainly infections and febrile neutropenia, with a strong impact on patient morbidity and mortality. Such complications have been shown to be closely related to alterations of the gut microbiome (GM), making the design of strategies to foster its eubiosis of utmost clinical importance. Here, we evaluated the impact of oral supplementation of lactoferrin (LF), a glycoprotein endowed with anti-inflammatory, immunomodulatory and antimicrobial activities, on GM dynamics in pediatric oncohematologic patients during induction chemotherapy. Specifically, we conducted a double blind, placebo-controlled trial in which GM was profiled through 16S rRNA gene sequencing before and after two weeks of oral supplementation with LF or placebo. LF was safely administered with no adverse effects and promoted GM homeostasis by favoring the maintenance of diversity and preventing the bloom of pathobionts (e.g., Enterococcus). LF could, therefore, be a promising adjunct to current therapeutic strategies in these fragile individuals to reduce the risk of GM-related complications.

Association of Gut Microbiota Enterotypes with Blood Trace Elements in Women with Infertility

Infertility is defined as failure to achieve pregnancy within 12 months of unprotected intercourse in women. Trace elements, a kind of micronutrient that is very important to female reproductive function, are affected by intestinal absorption, which is regulated by gut microbiota. Enterotype is the classification of an intestinal microbiome based on its characteristics. Whether or not Prevotella-enterotype and Bacteroides-enterotype are associated with blood trace elements among infertile women remains unclear. The study aimed to explore the relationship between five main whole blood trace elements and these two enterotypes in women with infertility. This retrospective cross-sectional study recruited 651 Chinese women. Whole blood copper, zinc, calcium, magnesium, and iron levels were measured. Quantitative real-time PCR was performed on all fecal samples. Patients were categorized according to whole blood trace elements (low levels group, <5th percentile; normal levels group, 5th‒95th percentile; high levels group, >95th percentile). There were no significant differences in trace elements between the two enterotypes within the control population, while in infertile participants, copper (P = 0.033), zinc (P < 0.001), magnesium (P < 0.001), and iron (P < 0.001) in Prevotella-enterotype was significantly lower than in Bacteroides-enterotype. The Chi-square test showed that only the iron group had a significant difference in the two enterotypes (P = 0.001). Among infertile patients, Prevotella-enterotype (Log(P/B) > −0.27) predicted the low levels of whole blood iron in the obesity population (AUC = 0.894; P = 0.042). For the high levels of iron, Bacteroides-enterotype (Log(P/B) <−2.76) had a predictive power in the lean/normal group (AUC = 0.648; P = 0.041) and Log(P/B) <−3.99 in the overweight group (AUC = 0.863; P = 0.013). We can infer that these two enterotypes may have an effect on the iron metabolism in patients with infertility, highlighting the importance of further research into the interaction between enterotypes and trace elements in reproductive function.

Gut Microbiota Dysbiosis in Childhood Vasculitis: A Perspective Comparative Pilot Study

Kawasaki disease (KD) and Henoch–Schönlein purpura (HSP) are the most frequent vasculitis in childhood. For both, a multifactorial mechanism has been hypothesised, with an abnormal immune response in genetically predisposed children. Gut microbiota (GM) alterations might trigger the hyperimmune reaction. Our aim was to explore the GM in KD and compare it with the GM of HSP and febrile children. Children diagnosed with KD, HSP and non-KD febrile illness (F) were enrolled. GM was profiled by 16S rRNA gene sequencing and compared with the profiles of healthy children from previous studies. We enrolled 13 KD, 10 HSP and 12 F children. Their GM significantly differed from controls, with an overall reduction in the relative abundance of beneficial taxa belonging to the Ruminococcaceae and Lachnospiraceae families. Potential KD and HSP signatures were identified, including smaller amounts of Dialister in the former, and Clostridium and Akkermansia in the latter. Notably, the GM structures of KD, HSP and F patients stratified by abdominal involvement, with more severe dysbiosis in those suffering from intestinal symptoms. This is the first study analysing GM in a mostly Caucasian cohort of KD and HSP children. Our data could open up new opportunities for childhood vasculitis treatment.

Influence of multistrain probiotic and iron supplementation on iron status in rats

OBJECTIVE

The impact of multistrain probiotics on iron (Fe) metabolism under Fe-deficient diet conditions remains unknown. The study aimed to compare the effect of 6 weeks simultaneous and exclusive oral multistrain probiotic and iron supplementation on selected parameters of Fe metabolism in rats on an Fe-deficient diet.

METHODS

Forty rats were assigned to five groups, with eight animals in each, and for 6 weeks received: the CC group- a standard diet, the DD group- an Fe-deficient diet, the DPB group- an Fe-deficient with a multispecies probiotic, the DFE group- an Fe-deficient diet supplemented with iron, the DPBFE group- an Fe-deficient diet with iron and a multispecies probiotic. The Fe content in blood and tissues; serum concentration of erythroferrone, ferritin (Ft), homocysteine, hepcidin (HEPC) and lactoferrin; liver content of divalent metal transporter 1 (DMT1), transferrin receptor protein 1 (TfR1) and 2 (TfR2) and ZRT/IRT-like protein 14 (ZIP14) and faecal microbiota were assessed.

RESULTS

In DPBFE group, unlike in DPB and DFE groups, duodenal Fe content was higher compared to DD group. Similarly, serum Ft level was higher in DPBFE group, but not in DPB and DFE groups, compared to DD group.

CONCLUSIONS

Six weeks simultaneous oral multistrain probiotic and Fe supplementation, but not exclusive probiotic or Fe intake, increases duodenal Fe absorption in rats and presents higher effectiveness in increasing tissue Fe stores.

Recent insights into the role of the microbiome in malignant and benign hematologic diseases

Growing evidence suggests the impact of microbiome alteration, named dysbiosis, on the development of neoplasms, infections, inflammatory diseases, and immuno-mediated disorders. Regarding hematologic diseases, most data regard hematopoietic stem cell transplant (HSCT). In this review, we systematically evaluate the studies concerning microbiome in malignant and benign hematologic disorders beyond HSCT. A permissive microbiota is associated to the development of hematologic malignancies (including acute leukemia, lymphoma, and multiple myeloma), as well as of iron deficiency anemia, autoimmune cytopenias, and aplastic anemia. This happens through various mechanisms; chronic inflammatory triggering, epithelial barrier alteration, antigen dissequestration, and molecular mimicry. Hematologic therapies (chemo and immunosuppression) may induce/worsen dysbiosis and favour disease progression and infectious complications. Antibiotics may also induce dysbiosis with possible long-term consequences. Finally, novel target therapies are likely to alter microbiome, inducing gut inflammation (i.e. small molecules such as tyrosine-kinase-inhibitors) or enhancing host's immune system (as observed with CAR-T cells and checkpoint inhibitors).

Gut Microbiota Signatures in Gestational Anemia

Gestational diseases are associated with altered intestinal microbiota in pregnant women. Characterizing the gut microbiota of gestational anemia (GA) may describe a novel role of gut microbial abnormality in GA. In this study, we investigated differences in gut microbiota between GA patients and healthy pregnant women from the first trimester (n = 24 vs. 54) and the third trimester (n = 30 vs. 56) based on the 16S rRNA gene sequencing method. No statistically significant differences in α-diversity were identified between GA patients and controls in the first trimester of pregnancy, whereas the Shannon index and observed OTUs were significantly lower in GA patients than in healthy controls in the third trimester. Distance-based redundancy analysis revealed striking differences in microbial communities in the third trimester between GA patients and controls. Four genera were significantly different in relative abundance between GA patients and healthy controls, while 12 genera differentiated significantly between GA patients and healthy controls in the third trimester. At the operational taxonomic unit (OTU) level, 17 OTUs and 30 OTUs were identified to be different between GA patients and healthy controls in the first and third trimesters, respectively. Changes in gut microbial composition of GA patients suggest a potential relation with GA, and provide insights into the prediction and intervention of gestational anemia.

Regulatory effects of transition metals supplementation/deficiency on the gut microbiota

Transition metal ions are essential micronutrients for all living organisms and exert a wide range of effects on human health. The uptake of transition metal ions occurs primarily in the gastrointestinal tract, which is colonized by trillions of bacterial cells. In recent years, increasing studies have indicated that transition metals have regulatory effects on the gut microbiota. In view of the significant effect of the gut microbiota on human health and involvement in the pathogenesis of a wide range of diseases, in this paper, we provide a comprehensive discussion on the regulatory effects of four kinds of transition metal ions on the gut microbiota. A total of 20 animal model and human studies concerning the regulatory effects of four types of transition metal ions (i.e., iron, copper, zinc, and manganese) on gut microbiota were summarized. Both the deficiency and supplementation of these transition metal ions on the gut microbiota were considered. Furthermore, the potential mechanisms governing the regulatory effects of transition metal ions on the gut microbiota were also discussed. KEY POINTS : • Regulatory effects of iron, copper, zinc, and manganese on gut microbiota were reviewed. • Both deficiency and supplementation of metal ions on gut microbiota were considered. • Mechanisms governing effects of metal ions on gut microbiota were discussed.

Iron homeostasis in host and gut bacteria - a complex interrelationship

Iron deficiency is the most frequent nutritional deficiency in the world with an estimated 1.4 billion people affected. The usual way to fight iron deficiency is iron fortification, but this approach is not always effective and can have undesirable side effects including an increase in the growth and virulence of gut bacterial pathogens responsible for diarrhea and gut inflammation. Iron is mainly absorbed in the duodenum and is tightly regulated in mammals. Unabsorbed iron enters the colonic lumen where many microorganisms, referred to as gut microbiota, reside. Iron is essential for these bacteria, and its availability consequently affects this microbial ecosystem. The aim of this review is to provide further insights into the complex relationship between iron and gut microbiota. Given that overcoming anemia caused by iron deficiency is still a challenge today, gut microbiota could help identify more efficient ways to tackle this public health problem.

Low-Dose Antibiotic Prophylaxis Induces Rapid Modifications of the Gut Microbiota in Infants With Vesicoureteral Reflux

Background and Objectives: Maturation of the gut microbiota (GM) in infants is critically affected by environmental factors, with potential long-lasting clinical consequences. Continuous low-dose antibiotic prophylaxis (CAP) is the standard of care for children with vesicoureteral reflux (VUR), in order to prevent recurrent urinary tract infections. We aimed to assess short-term GM modifications induced by CAP in infants. Methods: We analyzed the GM structure in 87 infants (aged 1-5 months) with high-grade VUR, previously exposed or naïve to CAP. Microbial DNA was extracted from stool samples. GM profiling was achieved by 16S rRNA gene-based next-generation sequencing. Fecal levels of short- and branched-chain fatty acids were also assessed. Results: 36/87 patients had been taking daily CAP for a median time of 47 days, while 51/87 had not. In all patients, the GM was predominantly composed by Bifidobacteriaceae and Enterobacteriaceae. Subgroup comparative analysis revealed alterations in the GM composition of CAP-exposed infants at phylum, family and genus level. CAP-exposed GM was enriched in members of Enterobacteriaceae and Bacteroidetes, especially in the genera Bacteroides and Parabacteroides, and showed a trend toward increased Klebsiella, often associated with antibiotic resistance. In contrast, the GM of non-CAP children was mostly enriched in Bifidobacterium. No differences were found in fatty acid levels. Conclusions: In infants with VUR, even a short exposure to CAP definitely alters the GM composition, with increased relative abundance of opportunistic pathogens and decreased proportions of health-promoting taxa. Early low-dose antibiotic exposure might bear potential long-term clinical risks.

Dietary Emulsifiers Alter Composition and Activity of the Human Gut Microbiota in vitro, Irrespective of Chemical or Natural Emulsifier Origin

The use of additives in food products has become an important public health concern. In recent reports, dietary emulsifiers have been shown to affect the gut microbiota, contributing to a pro-inflammatory phenotype and metabolic syndrome. So far, it is not yet known whether similar microbiome shifts are observable for a more diverse set of emulsifier types and to what extent these effects vary with the unique features of an individual's microbiome. To bridge this gap, we investigated the effect of five dietary emulsifiers on the fecal microbiota from 10 human individuals upon a 48 h exposure. Community structure was assessed with quantitative microbial profiling, functionality was evaluated by measuring fermentation metabolites, and pro-inflammatory properties were assessed with the phylogenetic prediction algorithm PICRUSt, together with a TLR5 reporter cell assay for flagellin. A comparison was made between two mainstream chemical emulsifiers (carboxymethylcellulose and P80), a natural extract (soy lecithin), and biotechnological emulsifiers (sophorolipids and rhamnolipids). While fecal microbiota responded in a donor-dependent manner to the different emulsifiers, profound differences between emulsifiers were observed. Rhamnolipids, sophorolipids, and soy lecithin eliminated 91 ± 0, 89 ± 1, and 87 ± 1% of the viable bacterial population after 48 h, yet they all selectively increased the proportional abundance of putative pathogens. Moreover, profound shifts in butyrate (-96 ± 6, -73 ± 24, and -34 ± 25%) and propionate (+13 ± 24, +88 ± 50, and +29 ± 16%) production were observed for these emulsifiers. Phylogenetic prediction indicated higher motility, which was, however, not confirmed by increased flagellin levels using the TLR5 reporter cell assay. We conclude that dietary emulsifiers can severely impact the gut microbiota, and this seems to be proportional to their emulsifying strength, rather than emulsifier type or origin. As biotechnological emulsifiers were especially more impactful than chemical emulsifiers, caution is warranted when considering them as more natural alternatives for clean label strategies.

Maternal Iron Deficiency Programs Offspring Cognition and Its Relationship with Gastrointestinal Microbiota and Metabolites

Iron is an essential micronutrient for the brain development of the fetus. Altered intestinal microbiota might affect behavior and cognition through the so-called microbiota-gut-brain axis. We used a Sprague-Dawley rat model of a maternal low-iron diet to explore the changes in cognition, dorsal hippocampal brain-derived neurotrophic factor (BDNF) and related pathways, gut microbiota, and related metabolites in adult male offspring. We established maternal iron-deficient rats by feeding them a low-iron diet (2.9 mg/kg), while the control rats were fed a standard diet (52.3 mg/kg). We used a Morris water maze test to assess spatial learning and long-term memory. Western blot (WB) assays and a quantitative reverse-transcription polymerase chain reaction (qRT-PCR) were used to detect the BDNF concentration and related signaling pathways. We collected fecal samples for microbiota profiling and measured the concentrations of plasma short-chain fatty acids. The adult male offspring of maternal rats fed low-iron diets before pregnancy, during pregnancy and throughout the lactation period had (1) spatial deficits, (2) a decreased BDNF mRNA expression and protein concentrations, accompanied by a decreased TrkB protein abundance, (3) a decreased plasma acetate concentration, and (4) an enrichment of the Bacteroidaceae genus Bacteroides and Lachnospiraceae genus Marvinbryantia. Maternal iron deficiency leads to an offspring spatial deficit and is associated with alternations in gastrointestinal microbiota and metabolites.

The impact of maternal and early life malnutrition on health: a diet-microbe perspective

BACKGROUND

Early-life malnutrition may have long-lasting effects on microbe-host interactions that affect health and disease susceptibility later in life. Diet quality and quantity in conjunction with toxin and pathogen exposure are key contributors to microbe-host physiology and malnutrition. Consequently, it is important to consider both diet- and microbe-induced pathologies as well as their interactions underlying malnutrition.

MAIN BODY

Gastrointestinal immunity and digestive function are vital to maintain a symbiotic relationship between the host and microbiota. Childhood malnutrition can be impacted by numerous factors including gestational malnutrition, early life antibiotic use, psychological stress, food allergy, hygiene, and exposure to other chemicals and pollutants. These factors can contribute to reoccurring environmental enteropathy, a condition characterized by the expansion of commensal pathobionts and environmental pathogens. Reoccurring intestinal dysfunction, particularly during the critical window of development, may be a consequence of diet-microbe interactions and may lead to life-long immune and metabolic programming and increased disease risk. We provide an overview of the some key factors implicated in the progression of malnutrition (protein, fat, carbohydrate, iron, vitamin D, and vitamin B12) and discuss the microbiota during early life that may contribute health risk later in life.

CONCLUSION

Identifying key microbe-host interactions, particularly those associated with diet and malnutrition requires well-controlled dietary studies. Furthering our understanding of diet-microbe-host interactions will help to provide better strategies during gestation and early life to promote health later in life.

Hepcidin and Erythroferrone Correlate with Hepatic Iron Transporters in Rats Supplemented with Multispecies Probiotics

The influence of probiotic supplementation on iron metabolism remains poorly investigated. However, a range of studies, especially on Lactobacillus plantarum 299v (Lp229v), have indicated a possible positive impact of probiotics on iron absorption. The aim of the study was to determine the effect of multistrain probiotic supply on iron balance. Thirty Wistar rats were randomized into three groups: placebo (KK group), and multistrain probiotic per os in a daily dose of 2.5 × 10⁹ colony forming units (CFU) (PA group) or 1 × 10¹⁰ CFU (PB group). Multistrain probiotic consisted of nine bacterial strains: Bifidobacterium bifidum W23, B. lactis W51, B. lactis W52, Lactobacillus acidophilus W37, L. brevis W63, L. casei W56, L. salivarius W24, Lactococcus lactis W19, and Lc. lactis W58, in equal proportions. After six weeks, blood and organ samples were collected. No differences were found between the three groups in terms of serum concentrations of hepcidin (HEPC), lactoferrin (LTF), homocysteine (HCY), ferritin (Ft), or erythroferrone (ErFe), or in liver content of divalent metal transporter 1 (DMT1), transferrin receptors 1 and 2 (TfR), or ZRT/IRT-like protein 14 (ZIP14) proteins. In the overall sample, positive correlations were noted between the serum concentrations of hepcidin and lactoferrin, and hepcidin and ferritin; serum concentration of hepcidin and DMT1 and TfR1 in the liver; and serum concentration of erythroferrone and TfR2 in the liver. The correlations of serum hepcidin and erythroferrone with liver DMT1 and TfR represent significant mechanisms of Fe homeostasis. Our study has shown that multistrain probiotic supplementation used in the experiment did not disrupt the biochemical and hepatic regulatory processes of Fe balance and did not demonstrate significant influence on selected parameters of Fe metabolism.

Infant growth, neurodevelopment and gut microbiota during infancy: which nutrients are crucial?

PURPOSE OF REVIEW

To update the role of specific nutrients during infant development.

RECENT FINDINGS

Several bioactive nutrients such as long-chain polyunsaturated fatty acids (LC-PUFAs), iron, vitamins, proteins, or carbohydrates have been identified to exert an important role during the first 1000 days of life on infant growth, neurodevelopment, and gut microbiota establishment and maturation. LC-PUFAs are structural constituents of the central nervous system (CNS), being essential in retinal development or hippocampal plasticity. Recently, components of the milk fat globule membrane (MFG) are being added to infant formulas because of their key role in infant's development. A high intake of proteins induces a faster weight gain during infancy which correlates with later obesity. Digestible carbohydrates provide glucose, crucial for an adequate functioning of CNS; nondigestible carbohydrates [e.g. human milk oligosaccharides (HMOs)] are the main carbon source for gut bacteria. Iron-deficiency anemia during infancy has been associated with alterations of mental and psychomotor development. Folate metabolism, closely related to vitamins B6 and B12, controls epigenetic changes, whereas inadequate status of vitamin D affects bone development, but may also increase intestinal permeability and alter gut microbiota composition.

SUMMARY

LC-PUFAs, proteins, carbohydrates, iron, and vitamins during early life are critical for infant's growth, neurodevelopment, and the establishment and functioning of gut microbiota.