Dietary and enteral interventions for Crohn's disease

Mechanisms of Action of Exclusive Enteral Nutrition and Other Nutritional Therapies in Crohn's Disease

BACKGROUND AND OBJECTIVES

Crohn's disease (CD) is an inflammatory bowel disease (IBD) characterized by transmural inflammation and intestinal fibrosis involving mostly the small intestine and colon. The pathogenic mechanisms of CD remain incompletely understood and cures are unavailable. Current medical therapies are aimed at inducing prolonged remission. Most of the medical therapies such as corticosteroids have substantial adverse effects. Consequently, many dietary therapies have been explored for the management of CD. Up to now, exclusive enteral nutrition (EEN) has been considered the only established dietary treatment for IBD, especially CD. In this article, we aim to give a concise review about the current therapeutic options and challenges in the management of CD and aim to compare the efficacy of EEN with other dietary therapies and update on the possible mechanisms of the benefits of EEN and other nutritional therapies.

METHODS

We searched the literature up to August 2024 through PubMed, Web of Science, and other sources using search terms such as EEN, nutritional therapy, IBD, Crohn's disease, ulcerative colitis. Clinical studies in patients and preclinical studies in rodent models of IBD were included in the summary of the therapeutic benefits.

RESULTS AND CONCLUSIONS

EEN involves oral or nasogastric tube feeding of a complete liquid diet with exclusion of normal foods for a defined period (usually 6 to 8 weeks). EEN treatment is demonstrated to have anti-inflammatory and healing effects in CD through various potential pathways, including altering gut bacteria and their metabolites, restoring the barrier function, direct anti-inflammatory action, and indirect anti-inflammatory action by eliminating mechanical stress in the bowel. However, efficacy of other nutritional therapies is not well established in CD, and mechanisms of action are largely unknown.

Remodeling of T-cell mitochondrial metabolism to treat autoimmune diseases

T cells are key drivers of the pathogenesis of autoimmune diseases by producing cytokines, stimulating the generation of autoantibodies, and mediating tissue and cell damage. Distinct mitochondrial metabolic pathways govern the direction of T-cell differentiation and function and rely on specific nutrients and metabolic enzymes. Metabolic substrate uptake and mitochondrial metabolism form the foundational elements for T-cell activation, proliferation, differentiation, and effector function, contributing to the dynamic interplay between immunological signals and mitochondrial metabolism in coordinating adaptive immunity. Perturbations in substrate availability and enzyme activity may impair T-cell immunosuppressive function, fostering autoreactive responses and disrupting immune homeostasis, ultimately contributing to autoimmune disease pathogenesis. A growing body of studies has explored how metabolic processes regulate the function of diverse T-cell subsets in autoimmune diseases such as systemic lupus erythematosus (SLE), multiple sclerosis (MS), autoimmune hepatitis (AIH), inflammatory bowel disease (IBD), and psoriasis. This review describes the coordination of T-cell biology by mitochondrial metabolism, including the electron transport chain (ETC), oxidative phosphorylation, amino acid metabolism, fatty acid metabolism, and one‑carbon metabolism. This study elucidated the intricate crosstalk between mitochondrial metabolic programs, signal transduction pathways, and transcription factors. This review summarizes potential therapeutic targets for T-cell mitochondrial metabolism and signaling in autoimmune diseases, providing insights for future studies.

"Out of the box" new therapeutic strategies for Crohn´s disease: moving beyond biologics

New treatment options beyond immunosuppression have emerged in recent years for patients with Crohn´s disease (CD), a chronic systemic condition affecting primarily the gut with great impact in the quality of life. The cause of CD is largely unknown, and a curative treatment is not yet available. In addition, despite the growing therapeutic armamentarium in recent years almost half of the patients don´t achieve a sustained response over time. Thus, new therapeutic strategies are urgently needed. In this review, we discuss the current state of promising new "out of the box" possibilities to control chronic inflammation beyond current pharmacological treatments, including: exclusive enteral nutrition, specific diets, cell therapies using T regs, hyperbaric oxygen, fecal microbiota transplantation, phage therapy, helminths, cannabis and vagal nerve stimulation. The exploration of original and novel therapeutic modalities is key to address their potential as main or complementary treatments in selected CD populations in order to increase efficacy, minimize side effects and improve quality of life of patients.

Clean Production of l-Alanyl-l-glutamine by an Efficient Yeast Biocatalyst Expressing α-Amino Acid Ester Acyltransferase without N-Glycosylation

l-Alanyl-l-glutamine (Ala-Gln) is a widely used value-added dipeptide whose production relies heavily upon an efficient biocatalyst. The currently available yeast biocatalysts that express α-amino acid ester acyltransferase (SsAet) possess relatively low activity, which may be attributed to glycosylation. Here, to promote SsAet activity in yeast, we identified the N-glycosylation site as the Asn residue at position 442 and subsequently eliminated the negative effect of N-glycosylation on SsAet by removing artificial and native signal peptides to obtain K3A1, a novel yeast biocatalyst with significantly improved activity. Additionally, the optimal reaction conditions of strain K3A1 were determined (25 °C, pH 8.5, AlaOMe/Gln = 1:2), resulting in a maximum molar yield and productivity of approximately 80% and 1.74 g·(L·min)^-1, respectively. Therefore, we developed a promising system to cleanly produce Ala-Gln in a safe, efficient, and sustainable manner, which may contribute to the future industrial production of Ala-Gln.

Oral exclusive enteral nutrition for induction of clinical remission, mucosal healing, and improvement of nutritional status and growth velocity in children with active Crohn's disease - a prospective multicentre trial

Introduction

Undernutrition and growth failure are common problems in paediatric patients with active Crohn's disease (CD).

Aim

The aim of exclusive enteral nutrition (EEN) commencement is not only to induce clinical remission and promote mucosal healing but also to initiate weight and growth gain, especially in patients with poor nutritional status. We assessed the effectiveness of treatment with EEN and its impact on nutritional status in children with active CD.

Material and methods

Twenty children (male/female: 14/6) in median age of 14 years with active CD had EEN with polymeric industrial diet (Modulen IBD) applied for 6 weeks. The daily caloric intake was established according to the age and nutritional status. In patients with undernutrition, it was increased to 120-150% relative to recommendations for the healthy peers. The Paediatric CD activity index (PCDAI) - a marker of clinical remission, faecal calprotectin (FCP) - a marker of mucosal healing (MH), and nutritional status were assessed at baseline and 4 weeks following the end of the therapy (week 10).

Results

In the studied group the mean decrease in PCDAI score was statistically significant (from 25.6 ±12 to 5.4 ±10, p < 0.05). Full remission (defined as PCDAI < 10) was achieved in 65% of patients, and clinical response in another 30% of them. Only 5% of children did not respond to the treatment. Mean decline in FCP level was statistically significant as well (from 3380 ±7746 to 1046.6 ±1219, p < 0.05). All patients, apart from one who was fed with a nasogastric tube, accepted oral intake of industrial formula. EEN was generally well tolerated. Initially, in 20% of patients the symptoms of intolerance to the industrial diet were observed, but they receded within the first days of the therapy. The recommended daily intake of the formula was achieved in 95% of children. Only one child was unable to intake the prescribed amount of the diet due to intolerance. At baseline, undernutrition was observed in 30% of patients, which was established by a body mass index (BMI) score below the third percentile according to the recommended charts for the Polish paediatric population. In all patients, improvement in BMI status was reported at the end of the treatment. The mean increase in BMI score was 0.91, and it was greater in the malnourished group compared to patients with normal nutritional status (1.19 vs. 0.62). After the treatment two-thirds of children with malnutrition achieved a BMI score within the normal range. In 25% of patients, growth deficit was observed (defined as growth below the third percentile according to the Polish charts) before the EEN introduction. An increase in body height was obtained generally in 55% of children and in 80% of those with initial growth failure. The mean increase in growth was 1 cm, and it was greater in the group with initial growth deficit relative to patients with baseline normal height (1.5 cm vs. 0.8 cm, respectively).

Conclusions

A 6-week course of oral EEN was an effective and well-tolerated method of treatment in children with active CD. Nutritional therapy not only induced full clinical remission and led to decline in FCP level (as a marker of MH) in the majority of patients, but also contributed to the improvement in their nutritional status and growth velocity. These are very important observations because proper development is crucial for paediatric CD patients.

Nutritional Treatment in Crohn's Disease

Crohn's disease (CD) is a chronic inflammatory bowel disease (IBD) which can affect any part of the whole gastrointestinal tract (from mouth to anus). Malnutrition affects 65-75% of CD patients, and it is now well acknowledged that diet is of paramount importance in the management of the disease. In this review, we would like to highlight the most recent findings in the field of nutrition for the treatment of CD. Our analysis will cover a wide range of topics, from the well-established diets to the new nutritional theories, along with the recent progress in emerging research fields, such as nutrigenomics.

Prescriber perspectives on low-value prescribing: A qualitative study

BACKGROUND

Health systems are increasingly implementing interventions to reduce older patients' use of low-value medications. However, prescribers' perspectives on medication value and the acceptability of interventions to reduce low-value prescribing are poorly understood.

OBJECTIVE

To identify the characteristics that affect the value of a medication and those factors influencing low-value prescribing from the perspective of primary care physicians.

DESIGN

Qualitative study using semi-structured interviews.

SETTING

Academic and community primary care practices within University of Pittsburgh Medical Center health system.

PARTICIPANTS

Sixteen primary care physicians.

MEASUREMENTS

We elicited 16 prescribers' perspectives on definitions and examples of low-value prescribing in older adults, the factors that incentivize them to engage in such prescribing, and the characteristics of interventions that would make them less likely to engage in low-value prescribing.

RESULTS

We identified three key themes. First, prescribers viewed low-value prescribing among older adults as common, characterized both by features of the medications themselves and of the particular patients to whom they were prescribed. Second, prescribers described the causes of low-value prescribing as multifactorial, with factors related to patients, prescribers, and the health system as a whole, making low-value prescribing a default practice pattern. Third, interventions addressing low-value prescribing must minimize the cognitive load and time pressures that make low-value prescribing common. Interventions increasing time pressure or cognitive load, such as increased documentation, were considered less acceptable.

CONCLUSIONS

Our findings demonstrate that low-value prescribing is a well-recognized phenomenon, and that interventions to reduce low-value prescribing must consider physicians' perspectives and address the specific patient, prescriber and health system factors that make low-value prescribing a default practice.

Identification of the relationship between the gut microbiome and feed efficiency in a commercial pig cohort

Feed efficiency (FE) is an economically important trait in pig production. Gut microbiota plays an important role in energy harvest, nutrient metabolism, and fermentation of dietary indigestible components. Whether and which gut microbes affect FE in pigs are largely unknown. Here, a total of 208 healthy Duroc pigs were used as experimental materials. Feces and serum samples were collected at the age of 140 d. We first performed 16S rRNA gene and metagenomic sequencing analysis to investigate the relationship between the gut microbiome and porcine residual feed intake (RFI). 16S rRNA gene sequencing analysis detected 21 operational taxonomic units showing the tendency to correlation with the RFI (P < 0.01). Metagenomic sequencing further identified that the members of Clostridiales, e.g., Ruminococcus flavefaoiens, Lachnospiraceae bacterium 28-4, and Lachnospiraceae phytofermentans, were enriched in pigs with low RFI (high-FE), while 11 bacterial species including 5 Prevotella spp., especially, the Prevotella copri, had higher abundance in pigs with high RFI. Functional capacity analysis suggested that the gut microbiome of low RFI pigs had a high abundance of the pathways related to amino acid metabolism and biosynthesis, but a low abundance of the pathways associated with monosaccharide metabolism and lipopolysaccharide biosynthesis. Serum metabolome and fecal short-chain fatty acids were determined by UPLC-QTOF/MS and gas chromatography, respectively. Propionic acid in feces and the serum metabolites related to amino acid metabolism were negatively correlated with the RFI. The results from this study may provide potential gut microbial biomarkers that could be used for improving FE in pig production industry.

Probiotics as a Coadjuvant Factor in Active or Quiescent Inflammatory Bowel Disease of Adults-A Meta-Analytical Study

(1) Background: Inflammatory bowel diseases are pathologies of unknown etiology and auto-immune pathogenia. The use of probiotics is studied in order to increase the arsenal of treatments. The aim was to assess the efficacy of the probiotics in these diseases in the active or quiescent phases; (2) Methods: A systematic review with meta-analysis was performed by an exhaustive bibliographic search in Medline, Cinahl, Embase, Scopus, Web of Science, and Cochrane Library. The inclusion criteria were studies of more than 10 years, English/Spanish, clinical trials, and involving human beings. Relative risk was used to compare efficacy, which was meta-analyzed using a fixed effects model. Heterogeneity was evaluated with the Higgins I² test; (3) Results: Nineteen studies were included in the systematic review and 17 in the meta-analysis, with a total of 1537 patients (n_{experimental group} = 762; n_{placebo group} = 775). There are significant remission differences in ulcerative colitis (relative risk (RR) = 0.81; 95% CI = 0.72–0.91; I² = 32%; p = 0.16). However, no significant differences were found in the use of probiotics for the prevention of ulcerative colitis, and for the remission of Crohn’s disease; (4) Conclusions: There are data showing an additional beneficial effect of probiotics on active ulcerative colitis. More and better studies are needed which assess its possible therapeutic efficacy for quiescent ulcerative colitis and for Crohn’s disease.

Does preoperative enteral nutrition reduce the incidence of surgical complications in patients with Crohn's disease? A case-matched study

AIM

Currently, the notion that preoperative optimization with enteral nutrition (EN) reduces the incidence of complication after surgery in Crohn's disease (CD) patients is being debated. This case-matched study was to evaluate the impact of preoperative EN on surgical outcomes in patients with CD.

METHOD

Twenty-four patients received EN therapy with an elemental diet (1800-2400 kcal/day) for at least 2 weeks before the planned surgery (EN group). A further 24 patients who underwent surgery without receiving preoperative EN or parenteral nutrition formed a control group based on four matched criteria: age (≤/>40 years), the use of preoperative medications (corticosteroids/azathioprine/biologics), disease behaviour (inflammatory/stricturing/penetrating) and main surgical procedure (ileal resection/ileocolonic resection/colectomy). The incidence of complications observed within 30 days after surgery was compared between the two groups. Septic complications were defined as anastomotic leak, intra-abdominal abscess, entero-cutaneous fistula or wound infection.

RESULTS

In the EN group, the median serum albumin level significantly increased, while C-reactive protein (CRP) significantly decreased during the preoperative EN (albumin, from 3.0 mg/dl to 3.1 mg/dl, P = 0.04; CRP, from 3.05 mg/dl to 2.52 mg/dl, P = 0.02). The incidence of postoperative septic complications was significantly lower in the EN group compared with the control group (4% vs 25%, P = 0.04). The occurrence rate of overall complications was lower in the EN group (21% vs 29%, P = 0.51), but not statistically significant.

CONCLUSION

In patients with CD, preoperative optimization with EN reduced the overall rate of postoperative complications and significantly decreased postoperative septic complications.

Gut Feelings Begin in Childhood: the Gut Metagenome Correlates with Early Environment, Caregiving, and Behavior

Psychosocial environments impact normative behavioral development in children, increasing the risk of problem behaviors and psychiatric disorders across the life span. Converging evidence demonstrates that early normative development is affected by the gut microbiome, which itself can be altered by early psychosocial environments. However, much of our understanding of the gut microbiome's role in early development stems from nonhuman animal models and predominately focuses on the first years of life, during peri- and postnatal microbial colonization. As a first step to identify if these findings translate to humans and the extent to which these relationships are maintained after initial microbial colonization, we conducted a metagenomic investigation among a cross-sectional sample of early school-aged children with a range of adverse experiences and caregiver stressors and relationships. Our results indicate that the taxonomic and functional composition of the gut microbiome correlates with behavior during a critical period of child development. Furthermore, our analysis reveals that both socioeconomic risk exposure and child behaviors associate with the relative abundances of specific taxa (e.g., Bacteroides and Bifidobacterium species) as well as functional modules encoded in their genomes (e.g., monoamine metabolism) that have been linked to cognition and health. While we cannot infer causality within this study, these findings suggest that caregivers may moderate the gut microbiome's link to environment and behaviors beyond the first few years of life.IMPORTANCE Childhood is a formative period of behavioral and biological development that can be modified, for better or worse, by the psychosocial environment that is in part determined by caregivers. Not only do our own genes and the external environment influence such developmental trajectories, but the community of microbes living in, on, and around our bodies-the microbiome-plays an important role as well. By surveying the gut microbiomes of a cross-sectional cohort of early school-aged children with a range of psychosocial environments and subclinical mental health symptoms, we demonstrated that caregiving behaviors modified the child gut microbiome's association to socioeconomic risk and behavioral dysregulation.

Strategy for the Biosynthesis of Short Oligopeptides: Green and Sustainable Chemistry

Short oligopeptides are some of the most promising and functionally important amide bond-containing components, with widespread applications. Biosynthesis of these oligopeptides may potentially become the ultimate strategy because it has better cost efficiency and environmental-friendliness than conventional solid phase peptide synthesis and chemo-enzymatic synthesis. To successfully apply this strategy for the biosynthesis of structurally diverse amide bond-containing components, the identification and selection of specific biocatalysts is extremely important. Given that perspective, this review focuses on the current knowledge about the typical enzymes that might be potentially used for the synthesis of short oligopeptides. Moreover, novel enzymatic methods of producing desired peptides via metabolic engineering are highlighted. It is believed that this review will be helpful for technological innovation in the production of desired peptides.

The Clinical Importance of 21-Day Combined Parenteral and Enteral Nutrition in Active Inflammatory Bowel Disease Patients

The aim of the study was to show the clinical magnitude of short-term feeding: enteral nutrition (EN) combined with parenteral nutrition (PN) in active Crohn's disease and ulcerative colitis patients. Among 122 eligible inflammatory bowel disease (IBD) patients, 65 met the inclusion criteria. Combined EN and PN was administered for 21 days, wherein over the first 3-5 days of treatment, trophic enteral nutrition (300 kcal/day) was used with an energy increase of up to 1500 kcal. An EN was administered using a nasogastric tube or, in case of intolerance, using a naso-jejunal tube. For PN, the "All in One" system was used according to individually prepared admixtures (ESPEN Guidelines). In addition to routine blood measurement (i.e., ALAT, ASPAT, GGTP, creatinine, lipid profile), the following parameters were assessed: adiponectin, leptin, (hs)TNF-α, hsIL-6 and hsIL-10, TSH, NT-proBNP, serum vitamin B12 concentration, and tHcy. The results showed a considerable improvement in all clinically significant parameters (p < 0.05), showing the benefits and importance of short-term well-balanced EN combined with PN for nutritional and clinical status in IBD patients with active disease. The daily work at hospitals with active IBD patients demonstrates the potential of continued administration of home-based nutrition by patients.

[Protective effect of procyanidin B2 on intestinal barrier and against enteritis in a mouse model of trinitrobenzene sulphonic acid-induced colitis]

OBJECTIVE

To investigate the protective effect of procyanidin B2 (PCB2) on the intestinal barrier and against enteritis in mice with trinitrobenzene sulphonic acid (TNBS)-induced colitis and explore the possible mechanism.

METHODS

A mouse model of TNBS-induced colitis was established in male Balb/c mice aged 6-8 weeks. The successfully established mouse models were randomly divided into PCB2 treatment group (n=10) and model group (n=10) and were treated with daily intragastric administration of PCB2 (100 mg/kg, 0.2 mL) and 0.2 mL normal saline, respectively. After 4 weeks, the disease symptoms, intestinal inflammation, intestinal mucosal cell barrier function and the changes in PI3K/AKT signaling were evaluated using HE staining, immunofluorescence assay and Western blotting.

RESULTS

The disease activity index of the mice was significantly lower and the mean body weight was significantly greater in PCB2 group than in the model group in the 3rd and 4th weeks of intervention (P < 0.05). The levels of colonic inflammation and intestinal mucosal inflammatory mediators IL-1β and TNF-α were significantly lower while IL-10 was significantly higher in PCB2 group than in the model group (P < 0.05). Compared with those in the model group, the mice in PCB2 treatment group showed a significantly lower positive rate of bacterial translocation in the mesenteric lymph nodes and a lower thiocyanate-dextran permeability of the intestinal mucosa (P < 0.05). Western blotting showed that PCB2 treatment significantly increased the expressions of claudin-1 and ZO-1 (P < 0.05) and significantly lowered the expression levels of p-PI3K and p-AKT in the intestinal mucosa as compared with those in the model group (P < 0.05).

CONCLUSIONS

PCB2 suppresses intestinal inflammation and protects intestinal mucosal functions and structural integrity by inhibiting intestinal PI3K/AKT signaling pathway, suggesting the potential of PCB2 as a new drug for Crohn's disease.

Spontaneous colitis in IL-10-deficient mice was ameliorated via inhibiting glutaminase1

Immunity imbalance and barrier damage in the intestinal mucosa are the main pathogenic factors of Crohn's disease (CD). Bis‐2‐(5‐phenylacetamido‐1,2,4‐thiadiazol‐2‐yl) ethyl sulfide (BPTES) is a glutaminase 1 (Gls1) inhibitor with the dual functions of increasing glutamine levels and immune regulation. In this study, we focused on the role of BPTES in CD‐like enteritis and the possible mechanisms. We found that Gls1 expression was significantly increased in CD intestinal tissue compared with control tissue. Bis‐2‐(5‐phenylacetamido‐1,2,4‐thiadiazol‐2‐yl) ethyl sulfide treatment significantly ameliorated chronic colitis in the IL‐10^−/−, as manifested by decreased disease activity index, body weight change, histological inflammatory degree and inflammatory cytokine expression. Bis‐2‐(5‐phenylacetamido‐1,2,4‐thiadiazol‐2‐yl) ethyl sulfide treatment exerted protective effects on CD that were associated with the maintenance of intestinal barrier integrity and the Th/Treg balance. Bis‐2‐(5‐phenylacetamido‐1,2,4‐thiadiazol‐2‐yl) ethyl sulfide treatment may act in part through TCR‐mediated mammalian target of rapamycin complex 1 (mTORC1) signalling activation. In conclusion, inhibition of Gls1 expression attenuated chronic colitis by maintaining intestinal barrier integrity and the Th/Treg balance, thereby ameliorating CD‐like colitis.

Dynamic Analysis of Metabolic Response in Gastric Ulcer (GU) Rats with Electroacupuncture Treatment Using 1H NMR-Based Metabolomics

Gastric ulcer (GU), a common digestive disease, has a high incidence and seriously endangers health of human. According to the previous studies, it has been proved that electroacupuncture at acupoints of stomach meridian had a good effect on GU. However, there are few published studies on metabolic response in gastric ulcer (GU) rats with electroacupuncture treatment. Herein, we observed the metabolic profiles in biological samples (stomach, liver, and kidney) of GU rats with electroacupuncture treatment by ¹H NMR metabolomics combined with pathological examination. The male SD rats were induced by intragastric administration of 70% ethanol after fasting for 24 hours and treated by electroacupuncture at Zusanli (ST36) and Liangmen (ST21) for 1 day, 4 days, or 7 days, respectively. And the conventional histopathological examinations as well as metabolic pathways assays were also performed. We found that GU rats were basically cured after electroacupuncture treatment for 4 days and had a complete recovery after electroacupuncture treatment for 7 days by being modulated comprehensive metabolic changes, involved in the function of neurotransmitters, energy metabolism, cells metabolism, antioxidation, tissue repairing, and other metabolic pathways. These findings may be helpful to facilitate the mechanism elucidating of electroacupuncture treatment on GU.

Production of L-alanyl-L-glutamine by immobilized Pichia pastoris GS115 expressing α-amino acid ester acyltransferase

Background

l-Alanyl-l-glutamine (Ala-Gln) represents the great application potential in clinic due to the unique physicochemical properties. A new approach was developed to synthesize Ala-Gln by recombinant Escherichia coli OPA, which could overcome the disadvantages of traditional chemical synthesis. Although satisfactory results had been obtained with recombinant E. coli OPA, endotoxin and the use of multiple antibiotics along with toxic inducer brought the potential biosafety hazard for the clinical application of Ala-Gln.

Results

In this study, the safer host Pichia pastoris was applied as an alternative to E. coli. A recombinant P. pastoris (named GPA) with the original gene of α-amino acid ester acyltransferase (SsAet) from Sphingobacterium siyangensis SY1, was constructed to produce Ala-Gln. To improve the expression efficiency of SsAet in P. pastoris, codon optimization was conducted to obtain the strain GPAp. Here, we report that Ala-Gln production by GPAp was approximately 2.5-fold more than that of GPA. The optimal induction conditions (cultivated for 3 days at 26 °C with a daily 1.5% of methanol supplement), the optimum reaction conditions (28 °C and pH 8.5), and the suitable substrate conditions (AlaOMe/Gln = 1.5/1) were also achieved for GPAp. Although most of the metal ions had no effects, the catalytic activity of GPAp showed a slight decrease in the presence of Fe³⁺ and an obvious increase when cysteine or PMSF were added. Under the optimum conditions, the Ala-Gln generation by GPAp realized the maximum molar yield of 63.5% and the catalytic activity of GPAp by agar embedding maintained extremely stable after 10 cycles.

Conclusions

Characterized by economy, efficiency and practicability, production of Ala-Gln by recycling immobilized GPAp (whole-cell biocatalyst) is represents a green and promising way in industrial.

Electronic supplementary material

The online version of this article (10.1186/s12934-019-1077-1) contains supplementary material, which is available to authorized users.

The Probiotic Effectiveness in Preventing Experimental Colitis Is Correlated With Host Gut Microbiota

Current evidence to support extensive use of probiotics in inflammatory bowel disease is limited and factors that contribute to the inconsistent effectiveness of clinical probiotic therapy are not completely known. Here, we used Bifidobacterium longum JDM 301 as a model probiotic to study potential factors that may influence the effect of probiotics in experimental colitis. We found that the effect of B. longum JDM 301 in tempering experimental colitis varied across individual mice even with the same genetic background. The probiotic efficacy was highly correlated with the host gut microbial community features. Consumption of a diet rich in fat could exacerbate mucosal injury-induced colitis but could not change the host responsiveness to B. longum JDM 301 treatment, suggesting of potential mechanistic differences between regulating colitis pathogenesis, and modulating probiotic efficacies by the gut microbiota. Together, our results suggest that personalized microbiome features may modify the probiotic therapeutic effect and support the idea of personalized probiotic medicine in inflammatory bowel disease.

DNA methylation changes and evolution of RNA-based duplication in Sus scrofa: based on a two-step strategy

AIM

This study aims to couple DNA methylation changes and evolution of retrogenes.

MATERIALS & METHODS

A new two-step strategy was developed to screen retrogenes. Further, reduced representation bisulfite sequencing and RNA-seq data of eight tissues were used to analyze retrogenes.

RESULTS

A total of 964 retrocopies were identified and new retrocopies were available for the synthesis of glycans and lipids corresponding to pig phenotypic traits. Retrogenes were consistently hypermethylated. Hypomethylation of parental genes presented more susceptibility to retroposition. Promoter DNA methylation of retrogenes was negatively correlated with evolutionary time and played important roles in regulating retrogene tissue-specific expression pattern.

CONCLUSION

A two-step procedure is effective and necessary for identifying retrogenes. DNA methylation drives origination, survival, evolution and expression of retrogenes.

Production of l-alanyl-l-glutamine by recycling E. coli expressing α-amino acid ester acyltransferase

In this study, the optimum induction and reaction conditions, and fermentation process of producing Ala-Gln by E. coli Origami 2 overexpressing α-amino acid ester acyltransferase (OPA) were investigated. Besides, the Ala-Gln synthesis by OPA achieved the maximum molar yield of 94.7% and productivity of 1.89g/L/min due to the extremely high enzyme activity. On this basis, repeated-cycle batch fermentation to produce Ala-Gln indicated that OPA could maintain high Ala-Gln yields and enzyme stabilities after several cell recycling. Consequently, the cost-efficient and environmentally friendly approach for Ala-Gln production by recycling OPA makes a great contribution to further industrial-scale applications.

Omega-3 fatty acids correlate with gut microbiome diversity and production of N-carbamylglutamate in middle aged and elderly women

Omega-3 fatty acids may influence human physiological parameters in part by affecting the gut microbiome. The aim of this study was to investigate the links between omega-3 fatty acids, gut microbiome diversity and composition and faecal metabolomic profiles in middle aged and elderly women. We analysed data from 876 twins with 16S microbiome data and DHA, total omega-3, and other circulating fatty acids. Estimated food intake of omega-3 fatty acids were obtained from food frequency questionnaires. Both total omega-3and DHA serum levels were significantly correlated with microbiome alpha diversity (Shannon index) after adjusting for confounders (DHA Beta(SE) = 0.13(0.04), P = 0.0006 total omega-3: 0.13(0.04), P = 0.001). These associations remained significant after adjusting for dietary fibre intake. We found even stronger associations between DHA and 38 operational taxonomic units (OTUs), the strongest ones being with OTUs from the Lachnospiraceae family (Beta(SE) = 0.13(0.03), P = 8 × 10-7). Some of the associations with gut bacterial OTUs appear to be mediated by the abundance of the faecal metabolite N-carbamylglutamate. Our data indicate a link between omega-3 circulating levels/intake and microbiome composition independent of dietary fibre intake, particularly with bacteria of the Lachnospiraceae family. These data suggest the potential use of omega-3 supplementation to improve the microbiome composition.

The Impact of Exclusive Enteral Nutrition (EEN) on the Gut Microbiome in Crohn's Disease: A Review

Crohn’s disease (CD), a form of inflammatory bowel disease (IBD), is thought to arise from a complex interaction of genetics, the gut microbiome, and environmental factors, such as diet. There is clear evidence that dietary intervention is successful in the treatment of CD—exclusive enteral nutrition (EEN) is able to induce remission in up to 80% of CD patients. While the mechanism of action of EEN is not clear, EEN is known to cause profound changes in the gut microbiome. Understanding how EEN modifies the gut microbiome to induce remission could provide insight into CD etiopathogenesis and aid the development of microbiome-targeted interventions to guide ongoing dietary therapy to sustain remission. This review includes current literature on changes in composition and function of the gut microbiome associated with EEN treatment in CD patients.