Glucagon-like peptide 2 for intestinal stem cell and Paneth cell repair during graft-versus-host disease in mice and humans

Immunotherapy in cancer

Immunotherapy has revolutionized the treatment of cancer. However, therapy resistance and immune mediated side effects reduce the overall success. Recent developments in these two areas were reported at the 2024 ATT conference. Here we discuss that immunotherapy resistance relies on immune escape mechanisms of cancer cells. Malignant conversion of a cell encompasses oncogene activation causing altered intracellular signal transduction termed "oncogenic signaling". A functional connection between oncogenic signaling and immune evasion mechanisms was shown for different haematological malignancies such as the FLT3-ITD/ATF6/IL-15 inhibition axis in acute myeloid leukemia. A second clinical problem are Immune mediated side effects after cancer immunotherapy because they lead to treatment interruption and potentially loss of activity by introduction of immunosuppressive medication. Anti-PD-1 immunotherapy induced inflammation of the central nervous system is rare but has a high morbidity and mortality. Recent data show that spleen tyrosine kinase (Syk) activation and downstream signaling in microglia mediates anti-PD-1 immunotherapy induced inflammation of the central nervous system.

Steroid Refractory Acute GVHD: The Hope for a Better Tomorrow

Steroid-refractory acute graft-versus-host disease (SR-AGVHD) presents a significant barrier to successful outcomes following allogeneic hematopoietic cell transplantation (HCT), despite advancements in GVHD prophylaxis and management. While ruxolitinib therapy has shown improved response rates, survival benefits remain elusive. This review explores the definitions and proposed distinct pathophysiology and treatment landscape of SR-AGVHD. Emerging therapies offer potential, yet further research is critical to better define steroid-refractory populations, improve treatment precision with biomarkers, and overcome resistance, particularly in ruxolitinib-refractory cases.

Teduglutide for treatment-refractory severe intestinal acute graft-versus-host disease - a multicenter survey

Intestinal glucocorticoid-refractory (SR) acute (a) graft-versus-host disease (GVHD) causes high non-relapse mortality (NRM) in patients after allogeneic hematopoietic cell transplantation (allo-HCT). Recent preclinical data indicate that acute GVHD causes a loss of intestinal neuroendocrine L-cells leading to reduced levels of glucagon-like peptide-2 (GLP-2). GLP-2 substitution improved GVHD severity and increased Paneth cells and intestinal stem cells in mice. This motivated us to treat patients with refractory intestinal aGHVD using the GLP-2-analogon teduglutide. In this retrospective multicenter survey, 17 patients received teduglutide as salvage-therapy for SR-intestinal aGVHD. The best response (CR or PR) at any time point during and after treatment was 64.7% (11/17) including 41.2% (7/17) CR and 23.5% (4/17) PR. At a median follow-up of 28 weeks after teduglutide 10/17 patients are alive. Most patients experienced an increase of the albumin serum level within 2 months after the first teduglutide dose, including patients who clinically did not respond to teduglutide treatment. No specific teduglutide-related toxicity was observed. Our retrospective analysis suggests that teduglutide is safe and has activity in a fraction of patients with intestinal SR-aGVHD, which needs validation in a prospective trial.

Evolution and therapeutic potential of glucagon-like peptide 2 analogs

Glucagon-like peptide 2 (GLP-2) is a proglucagon-derived peptide released by intestinal endocrine cells. However, its therapeutic potential is limited by rapid inactivation via dipeptidyl peptidase-IV. The elucidation of three-dimensional structures of G-protein-coupled receptors, including GLP-2 receptor, has facilitated the rational design of novel peptide therapeutics. Recent studies have explored various structural modifications based on the structure of GLP-2, such as amino acid substitution, lipidation, and fusion with proteins, to extend the half-life of GLP-2 and enhance its biological activity. One promising avenue involves the development of multifunctional molecules targeting multiple pharmacological systems to boost therapeutic efficacy. This paper reviews the recent advancements in understanding GLP-2, including its physiological roles and structure-activity relationships, and evaluates the development prospects of GLP-2 analogs.

Future biomarkers for acute graft-versus-host disease: potential roles of nucleic acids, metabolites, and immune cell markers

INTRODUCTION

Acute graft versus host disease (aGVHD) is a potentially lethal complication after allogeneic stem cell transplantation. Biomarkers are used to estimate the risk of aGVHD and evaluate response to treatment. The most widely used biomarkers are systemic levels of various protein mediators involved in immunoregulation or reflecting tissue damage. However, systemic levels of other molecular markers such as nucleic acids or metabolites, levels of immunocompetent cells or endothelial cell markers may also be useful biomarkers in aGVHD.

AREAS COVERED

This review is based on selected articles from the PubMed database. We review and discuss the scientific basis for further studies to evaluate nucleic acids, metabolites, circulating immunocompetent cell subsets or endothelial markers as biomarkers in aGVHD.

EXPERT OPINION

A wide range of interacting and communicating cells are involved in the complex pathogenesis of aGVHD. Both nucleic acids and metabolites function as soluble mediators involved in communication between various subsets of immunocompetent cells and between immunocompetent cells and other neighboring cells. Clinical and experimental studies suggest that both neutrophils, monocytes, and endothelial cells are involved in the early stages of aGVHD pathogenesis. In our opinion, the possible clinical use of these molecular and cellular biomarkers warrants further investigation.

Trichinella spiralis excretory/secretory antigens ameliorate porcine epidemic diarrhea virus-induced mucosal damage in porcine intestinal oganoids by alleviating inflammation and promoting tight junction

Trichinella spiralis and porcine epidemic diarrhea virus (PEDV) are two infectious swine pathogens. Parasite excretory/secretory antigens play critical roles in various disease processes. To explore the coexistence mechanism of two pathogens infecting the same host, the intestinal organoid was utilized to reproduce these biological processes. In this study, we investigated the effects of T. spiralis excretory/secretory antigens (TsES) on PEDV-induced inflammatory regulation, lesion recovery, and mucosal barrier repair in porcine intestinal organoids. The results showed that PEDV effectively infected the porcine intestinal organoids. Next, TsES inhibited pro-inflammatory cytokines and increased the anti-inflammatory cytokines produced by PEDV-infected porcine intestinal organoids. Further, four-dimensional (4D) label-free quantitative proteomics and western blotting confirmed that TsES regulate the inflammation caused by PEDV infection through the nuclear factor kappa-B (NF-κB) pathway. In addition, TsES promoted cell proliferation, inhibited apoptosis, and reduced PEDV-induced lesions in intestinal organoids. The elevated secretory immunoglobulin A (sIgA) levels caused by PEDV infection were downregulated by TsES treatment in intestinal organoids. TsES treatment reversed the mucosal barrier damage caused by PEDV infection in intestinal organoids. Finally, PEDV replication increased after TsES treatment in organoids. We highlight the potential of TsES to ameliorate PEDV-induced inflammation, mucosal lesions, and barrier damage in porcine intestinal organoids. TsES also contribute to PEDV replication. This study presents a novel research model for research on host-virus-parasite interactions, while also providing a theoretical foundation to consider parasite derivatives as a potential adjunctive therapy for intestinal inflammation.

Recent advances in acute gastrointestinal graft versus host disease (aGvHD): aspects of steroid-resistant disease

Acute Graft versus Host Disease (aGvHD) is a common immunological complication occurring in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Moreover, aGvHD is associated with a higher risk of infections and metabolic complications, affecting non-relapse mortality. Progress in transplantation has changed the prophylactic and therapeutic strategies of aGvHD and improved patient outcomes. The standard first-line therapy remains steroids, with a response rate of about 50%. The Janus Kinase 2 (JAK2) inhibitor, ruxolitinib, is an effective second-line therapy. The management of patients who developed a disease that is refractory to steroids and ruxolitinib, especially in the severe gastrointestinal forms of aGvHD, is not validated and remains an unmet medical need. In the article, we present the current clinical practice, as well as the latest advances targeting pathophysiological pathways of GvHD and gut microbiota, which may be a potential future of aGvHD therapy.

Advancing therapeutic strategies for graft-versus-host disease by targeting gut microbiome dynamics in allogeneic hematopoietic stem cell transplantation: current evidence and future directions

Hematopoietic stem cell transplantation (HSCT) is a highly effective therapy for malignant blood illnesses that pose a high risk, as well as diseases that are at risk due to other variables, such as genetics. However, the prevalence of graft-versus-host disease (GVHD) has impeded its widespread use. Ensuring the stability of microbial varieties and associated metabolites is crucial for supporting metabolic processes, preventing pathogen intrusion, and modulating the immune system. Consequently, it significantly affects the overall well-being and susceptibility of the host to disease. Patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) may experience a disruption in the balance between the immune system and gut bacteria when treated with medicines and foreign cells. This can lead to secondary intestinal inflammation and GVHD. Thus, GM is both a reliable indicator of post-transplant mortality and a means of enhancing GVHD prevention and treatment after allo-HSCT. This can be achieved through various strategies, including nutritional support, probiotics, selective use of antibiotics, and fecal microbiota transplantation (FMT) to target gut microbes. This review examines research advancements and the practical use of intestinal bacteria in GVHD following allo-HSCT. These findings may offer novel insights into the prevention and treatment of GVHD after allo-HSCT.

Glucose-dependent insulinotropic polypeptide receptor signaling alleviates gut inflammation in mice

Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) are gut-derived peptide hormones that potentiate glucose-dependent insulin secretion. The clinical development of GIP receptor-GLP-1 receptor (GIPR-GLP-1R) multiagonists exemplified by tirzepatide and emerging GIPR antagonist-GLP-1R agonist therapeutics such as maritide is increasing interest in the extrapancreatic actions of incretin therapies. Both GLP-1 and GIP modulate inflammation, with GLP-1 also acting locally to alleviate gut inflammation in part through antiinflammatory actions on GLP-1R+ intestinal intraepithelial lymphocytes. In contrast, whether GIP modulates gut inflammation is not known. Here, using gain- and loss-of-function studies, we show that GIP alleviates 5-fluorouracil-induced (5FU-induced) gut inflammation, whereas genetic deletion of Gipr exacerbates the proinflammatory response to 5FU in the murine small bowel (SB). Bone marrow (BM) transplant studies demonstrated that BM-derived Gipr-expressing cells suppress 5FU-induced gut inflammation in the context of global Gipr deficiency. Within the gut, Gipr was localized to nonimmune cells, specifically stromal CD146+ cells. Hence, the extrapancreatic actions of GIPR signaling extend to the attenuation of gut inflammation, findings with potential translational relevance for clinical strategies modulating GIPR action in people with type 2 diabetes or obesity.

Pathophysiology and preclinical relevance of experimental graft-versus-host disease in humanized mice

Graft-versus-host disease (GVHD) is a life-threatening complication of allogeneic hematopoietic cell transplantations (allo-HCT) used for the treatment of hematological malignancies and other blood-related disorders. Until recently, the discovery of actionable molecular targets to treat GVHD and their preclinical testing was almost exclusively based on modeling allo-HCT in mice by transplanting bone marrow and splenocytes from donor mice into MHC-mismatched recipient animals. However, due to fundamental differences between human and mouse immunology, the translation of these molecular targets into the clinic can be limited. Therefore, humanized mouse models of GVHD were developed to circumvent this limitation. In these models, following the transplantation of human peripheral blood mononuclear cells (PBMCs) into immunodeficient mice, T cells recognize and attack mouse organs, inducing GVHD. Thereby, humanized mice provide a platform for the evaluation of the effects of candidate therapies on GVHD mediated by human immune cells in vivo. Understanding the pathophysiology of this xenogeneic GVHD is therefore crucial for the design and interpretation of experiments performed with this model. In this article, we comprehensively review the cellular and molecular mechanisms governing GVHD in the most commonly used model of xenogeneic GVHD: PBMC-engrafted NOD/LtSz-PrkdcscidIL2rγtm1Wjl (NSG) mice. By re-analyzing public sequencing data, we also show that the clonal expansion and the transcriptional program of T cells in humanized mice closely reflect those in humans. Finally, we highlight the strengths and limitations of this model, as well as arguments in favor of its biological relevance for studying T-cell reactions against healthy tissues or cancer cells.

The Long-Acting Glucagon-Like Peptide-2 Analog Apraglutide Enhances Intestinal Protection and Survival After Chemotherapy and Allogeneic Transplantation in Mice

BACKGROUND The gastrointestinal (GI) barrier can be damaged by chemotherapy or radiation therapy, causing fatigue, malnutrition, sepsis, dose-limiting toxicity, and, occasionally, death. Glucagon-like peptide-2 (GLP-2) promotes mucosal epithelium growth and repair in the GI tract. Here, we examined the GI-protective effects of apraglutide, a long-acting peptide GLP-2 analog, in murine models of chemotherapy, and total body irradiation followed by allogeneic transplantation. MATERIAL AND METHODS The impact of apraglutide on cytarabine or melphalan chemotherapy-induced intestinal damage was assessed in BALB/c mice, and the effect on allogeneic transplantation in BALB/cJ and C57BL/6J mice. Outcomes included survival, and changes in body weight, intestinal function and morphology, including colon length and bacterial composition of the intestinal microbiota. RESULTS Adding apraglutide to chemotherapy significantly improved survival rates and reduced weight loss, with no impact on leukocyte counts (and, therefore, no effect on chemotherapy-induced immunosuppression), compared with chemotherapy alone in mice. These benefits were associated with preservation of the morphological integrity of the GI mucosa, attenuation of the negative impact of cytarabine on the intestinal microbiota, and significant improvement in plasma levels of citrulline. In addition, in a model of irradiation followed by allogeneic transplantation, mice in groups receiving apraglutide had improved survival, reduced weight loss, and increased colon length compared with those that did not. CONCLUSIONS Apraglutide protects intestinal function and improves survival in mice following allogeneic transplantation or chemotherapy with cytarabine or melphalan. The potential effect of apraglutide on chemotherapy efficacy and on engraftment following allogeneic transplantation has been investigated in a parallel manuscript.

Deciphering the role of the major histocompatibility complex, the intestinal microbiome and metabolites in the pathogenesis of acute graft-versus-host disease

Allogeneic hematologic stem cell transplantation is a cornerstone in modern hematological treatment, yet its efficacy is compromised by acute Graft-versus-Host Disease. In acute Graft-versus-Host Disease, conditioning regimen induced epithelial damage leads to release of damage and pathogen associated molecular patters which in turns triggers activation of alloreactive donor T cells, ultimately resulting in destruction of healthy tissue. Advances in major histocompatibility complex typing and preclinical studies using tissue specific major histocompatibility complex deletion have illuminated the contributions of both, hematopoietic and non-hematopoietic cells to acute Graft-versus-Host Disease pathophysiology. Concurrently, high-throughput sequencing techniques have enabled researchers to recognize the significant impact of the intestinal microbiome and newly discovered metabolites in the pathophysiology of acute Graft-versus-Host Disease. In this review, we discuss the implications of major histocompatibility complex expression on hematopoietic and non-hematopoietic cells, the effect on the intestinal microbiome and the metabolic alterations that contribute to acute Graft-versus-Host Disease. By combining these findings, we hope to untangle the complexity of acute Graft-versus-Host Disease, ultimately paving the way for the development of novel and more effective treatmen options in patients.

New investigational drugs for steroid-refractory acute graft-versus-host disease: a review of the literature

INTRODUCTION

Steroid-refractory acute graft-versus-host disease (SR-aGVHD) remains a formidable obstacle in the field of allogeneic hematopoietic cell transplantation (allo-HCT), significantly contributing to patient morbidity and mortality. The current therapeutic landscape for SR-aGVHD is limited, often yielding suboptimal results, thereby emphasizing the urgent need for innovative and effective treatments.

AREAS COVERED

In light of the pivotal REACH2 trial, ruxolitinib phosphate, a Janus kinase inhibitor, has gained prominence as the standard treatment for SR-aGVHD. Nevertheless, a considerable number of patients either do not respond to or cannot tolerate this therapy. This review delves into emerging treatments for SR-aGVHD, including mesenchymal stromal cells (MSCs), fecal microbiota transplantation (FMT), CD3/CD7 blockade, neihulizumab, begelomab, tocilizumab, and vedolizumab. While some of these agents have shown encouraging results in early-phase trials, issues such as treatment-related toxicities and inconsistent responses in larger studies highlight the necessity for ongoing research.

EXPERT OPINION

Current trials exploring new agents and combination therapies offer hope for fulfilling the unmet clinical needs in SR-aGVHD, potentially leading to more effective and precise treatment strategies.

Role of mucositis in predicting gut microbiota composition in people with cancer

PURPOSE OF REVIEW

Disruption of the precious ecosystem of micro-organisms that reside in the gut - the gut microbiota - is rapidly emerging as a key driver of the adverse side effects/toxicities caused by numerous anti-cancer agents. Although the contribution of the gut microbiota to these toxicities is understood with ever increasing precision, the cause of microbial disruption (dysbiosis) remains poorly understood. Here, we discuss current evidence on the cause(s) of dysbiosis after cancer therapy, positioning breakdown of the intestinal mucosa (mucositis) as a central cause.

RECENT FINDINGS

Dysbiosis in people with cancer has historically been attributed to extensive antibiotic use. However, evidence now suggests that certain antibiotics have minimal impacts on the microbiota. Indeed, recent evidence shows that the type of cancer therapy predicts microbiota composition independently of antibiotics. Given most anti-cancer drugs have modest effects on microbes directly, this suggests that their impact on the gut microenvironment, in particular the mucosa, which is highly vulnerable to cytotoxicity, is a likely cause of dysbiosis. Here, we outline evidence that support this hypothesis, and discuss the associated clinical implications/opportunities.

SUMMARY

The concept that mucositis dictates microbiota compositions provides two important implications for clinical practice. Firstly, it reiterates the importance of prioritising the development of novel mucoprotectants that preserve mucosal integrity, and indirectly support microbial stability. Secondly, it provides an opportunity to identify dysbiotic events and associated consequences using readily accessible, minimally invasive biomarkers of mucositis such as plasma citrulline.

Use of Teduglutide in the Management of Gastrointestinal Graft-versus-Host Disease in Children and Young Adults

Loss of intestinal L cells and reduced levels of glucagon-like peptide-2 (GLP-2) have been implicated in acute graft-versus-host disease (GVHD) in murine models. Teduglutide, a human recombinant GLP-2 analog, may be beneficial in acute gastrointestinal (GI) GVHD owing to its known tissue protective and regenerative functions. We retrospectively reviewed patients who received teduglutide for treatment of GI GVHD. Endoscopy was performed at diagnosis and at completion of the teduglutide course. GLP-1 immunohistochemistry (IHC) was performed at diagnosis and the end of teduglutide therapy in 2 patients to evaluate L cells. We initiated daily teduglutide 0.05 mg/kg subcutaneously as adjunctive therapy in 3 pediatric patients with refractory GI GVHD. All 3 patients had resolution of GI GVHD following completion of the teduglutide course, as evidenced by reduced apoptosis and regenerative changes on post-treatment endoscopy. Reportable GLP-1 IHC in 2 patients demonstrated increased L cells at the end of teduglutide treatment compared to at diagnosis. No adverse effects to teduglutide were observed. Teduglutide is a promising adjunctive and non-immune suppressive agent for managing acute GI GVHD.

Role of the GLP2-Wnt1 axis in silicon-rich alkaline mineral water maintaining intestinal epithelium regeneration in piglets under early-life stress

Stress-induced intestinal epithelial injury (IEI) and a delay in repair in infancy are predisposing factors for refractory gut diseases in adulthood, such as irritable bowel syndrome (IBS). Hence, it is necessary to develop appropriate mitigation methods for mammals when experiencing early-life stress (ELS). Weaning, as we all know, is a vital procedure that all mammalian newborns, including humans, must go through. Maternal separation (MS) stress in infancy (regarded as weaning stress in animal science) is a commonly used ELS paradigm. Drinking silicon-rich alkaline mineral water (AMW) has a therapeutic effect on enteric disease, but the specific mechanisms involved have not been reported. Herein, we discover the molecular mechanism by which silicon-rich AMW repairs ELS-induced IEI by maintaining intestinal stem cell (ISC) proliferation and differentiation through the glucagon-like peptide (GLP)2-Wnt1 axis. Mechanistic study showed that silicon-rich AMW activates GLP2-dependent Wnt1/β-catenin pathway, and drives ISC proliferation and differentiation by stimulating Lgr5+ ISC cell cycle passage through the G1-S-phase checkpoint, thereby maintaining intestinal epithelial regeneration and IEI repair. Using GLP2 antagonists (GLP23-33) and small interfering RNA (SiWnt1) in vitro, we found that the GLP2-Wnt1 axis is the target of silicon-rich AMW to promote intestinal epithelium regeneration. Therefore, silicon-rich AMW maintains intestinal epithelium regeneration through the GLP2-Wnt1 axis in piglets under ELS. Our research contributes to understanding the mechanism of silicon-rich AMW promoting gut epithelial regeneration and provides a new strategy for the alleviation of ELS-induced IEI.

Lipocalin-2 expression identifies an intestinal regulatory neutrophil population during acute graft-versus-host disease

Acute graft-versus-host disease (aGVHD) is a life-threatening complication of allogeneic hematopoietic cell transplantation (allo-HCT), for which therapeutic options are limited. Strategies to promote intestinal tissue tolerance during aGVHD may improve patient outcomes. Using single-cell RNA sequencing, we identified a lipocalin-2 (LCN2)-expressing neutrophil population in mice with intestinal aGVHD. Transfer of LCN2-overexpressing neutrophils or treatment with recombinant LCN2 reduced aGVHD severity, whereas the lack of epithelial or hematopoietic LCN2 enhanced aGVHD severity and caused microbiome alterations. Mechanistically, LCN2 induced insulin-like growth factor 1 receptor (IGF-1R) signaling in macrophages through the LCN2 receptor SLC22A17, which increased interleukin-10 (IL-10) production and reduced major histocompatibility complex class II (MHCII) expression. Transfer of LCN2-pretreated macrophages reduced aGVHD severity but did not reduce graft-versus-leukemia effects. Furthermore, LCN2 expression correlated with IL-10 expression in intestinal biopsies in multiple cohorts of patients with aGVHD, and LCN2 induced IGF-1R signaling in human macrophages. Collectively, we identified a LCN2-expressing intestinal neutrophil population that reduced aGVHD severity by decreasing MHCII expression and increasing IL-10 production in macrophages. This work provides the foundation for administration of LCN2 as a therapeutic approach for aGVHD.

Bacteria and bacteriophage consortia are associated with protective intestinal metabolites in patients receiving stem cell transplantation

The microbiome is a predictor of clinical outcome in patients receiving allogeneic hematopoietic stem cell transplantation (allo-SCT). Microbiota-derived metabolites can modulate these outcomes. How bacteria, fungi and viruses contribute to the production of intestinal metabolites is still unclear. We combined amplicon sequencing, viral metagenomics and targeted metabolomics from stool samples of patients receiving allo-SCT (n = 78) and uncovered a microbiome signature of Lachnospiraceae and Oscillospiraceae and their associated bacteriophages, correlating with the production of immunomodulatory metabolites (IMMs). Moreover, we established the IMM risk index (IMM-RI), which was associated with improved survival and reduced relapse. A high abundance of short-chain fatty acid-biosynthesis pathways, specifically butyric acid via butyryl-coenzyme A (CoA):acetate CoA-transferase (BCoAT, which catalyzes EC 2.8.3.8) was detected in IMM-RI low-risk patients, and virome genome assembly identified two bacteriophages encoding BCoAT as an auxiliary metabolic gene. In conclusion, our study identifies a microbiome signature associated with protective IMMs and provides a rationale for considering metabolite-producing consortia and metabolite formulations as microbiome-based therapies.

Evolution of GCGR family ligand-receptor extensive cross-interaction systems suggests a therapeutic direction for hyperglycemia in mammals

Glucose is essential to the physiological processes of vertebrates. Mammalian physiological stability requires a relatively stable blood glucose level (~5 mM), whereas other vertebrates have greater flexibility in regulating blood glucose (0.5-25 mM). GCGR family receptors play an important role in vertebrate glucose regulation. Here, we examine the evolution of the GCGR family ligand-receptor systems in different species. Comparatively, we discover that the conserved sequences among GCG family ligands lead to the non-specific activation of ligands across species. In particular, we observe that glucagon-like peptide 1 receptor (GLP1R), glucagon-like peptide 2 receptor (GLP2R), and glucagon-like receptor (GCGLR, also called GCRPR) are arbitrarily activated by other members of the ligand family in birds. Moreover, we reveal that Gallus gallus GLP2 (gGLP2) effectively activates mammalian GLP1R and improves glucose tolerance in diabetic mice. Our study has important implications for understanding blood glucose stabilization in vertebrates and demonstrates that gGLP2 may be a potential drug for treating type 2 diabetes.

Separation of GVL from GVHD -location, location, location

Allogeneic hematopoietic cell transplantation (HCT) is a curative therapy for various hematologic malignancies. However, alloimmune response is a double-edged sword that mediates both beneficial graft-versus-leukemia (GVL) effects and harmful graft-versus-host disease (GVHD). Separation of GVL effects from GVHD has been a topic of intense research to improve transplant outcomes, but reliable clinical strategies have not yet been established. Target tissues of acute GVHD are the skin, liver, and intestine, while leukemic stem cells reside in the bone marrow. Tissue specific effector T-cell migration is determined by a combination of inflammatory and chemotactic signals that interact with specific receptors on T cells. Specific inhibition of donor T cell migration to GVHD target tissues while preserving migration to the bone marrow may represent a novel strategy to separate GVL from GVHD. Furthermore, tissue specific GVHD therapy, promoting tissue tolerance, and targeting of the tumor immune microenvironment may also help to separate GVHD and GVL.

The best GVHD prophylaxis: Or at least progress towards finding it

Options for GVHD prophylaxis after allogeneic hematopoietic cell transplantation can best be chosen by understanding the pathophysiology of GVHD. Interventions to limit T cell activation, expansion and subsequent tissue injury can each be utilized in designing successful GVHD prevention strategies Depleting, tolerizing or blunting T cells or host antigen presenting cells (APCs), blocking co-stimulation or more broadly suppressing inflammation have all been used. Interventions which spare regulatory T cells (Tregs) may prevent GVHD and facilitate controlled allo-responses and not compromise subsequent relapse risks. Graft manipulations and pharmacologic interventions each have potential to limit the morbidity of GVHD while permitting the immunocompetence to prevent infection or relapse.

Curcumin Compensates GLP-1 Deficiency via the Microbiota-Bile Acids Axis and Modulation in Functional Crosstalk between TGR5 and FXR in ob/ob Mice

SCOPE

Glucagon-like peptide-1 (GLP-1) deficiency occurs in obesity-related pathologies due to defects in the intestinal lumen. And expanding the L-cell population has emerged as a promising avenue to elevate GLP-1 secretion to tackle metabolic disorders. Curcumin (Cur), the principal active component of spice turmeric, possesses well-established anti-obesity properties. To clarify, the study investigates whether Cur promotes GLP-1 secretion built upon the L-cell expansion.

METHODS AND RESULTS

Cur (60 mg kg-1 ) is administered orally to male ob/ob mice for 8 weeks. Cur ameliorates obesity and impaires glucose tolerance through increasing energy expenditure in ob/ob mice, accompanied by the maintenance of crypt architecture and gut permeability. It refines the microbial structure and bile acid (BA) profiles, resulting in deoxycholic acid (DCA) accumulation by weakening the enrichment of Lactobacillus. Further analyses show radically different properties of Cur on the intestine function of TGR5 and FXR (i.e., activation and repression). Cur amplifies L-cell number to promote GLP-1 secretion in ob/ob mice.

CONCLUSIONS

The findings suggest that Cur may act as a natural TGR5 agonist and FXR antagonist to improve obesity by enhancing GLP-1 release from L-cell expansion via the gut microbiota-BAs-TGR5/FXR axis, and it may serve as a promising therapeutic agent to compensate obesity-related metabolic disorders.

Control of Paneth cell function by HuR regulates gut mucosal growth by altering stem cell activity

Rapid self-renewal of the intestinal epithelium requires the activity of intestinal stem cells (ISCs) that are intermingled with Paneth cells (PCs) at the crypt base. PCs provide multiple secreted and surface-bound niche signals and play an important role in the regulation of ISC proliferation. Here, we show that control of PC function by RNA-binding protein HuR via mitochondria affects intestinal mucosal growth by altering ISC activity. Targeted deletion of HuR in mice disrupted PC gene expression profiles, reduced PC-derived niche factors, and impaired ISC function, leading to inhibited renewal of the intestinal epithelium. Human intestinal mucosa from patients with critical surgical disorders exhibited decreased levels of tissue HuR and PC/ISC niche dysfunction, along with disrupted mucosal growth. HuR deletion led to mitochondrial impairment by decreasing the levels of several mitochondrial-associated proteins including prohibitin 1 (PHB1) in the intestinal epithelium, whereas HuR enhanced PHB1 expression by preventing microRNA-195 binding to the Phb1 mRNA. These results indicate that HuR is essential for maintaining the integrity of the PC/ISC niche and highlight a novel role for a defective PC/ISC niche in the pathogenesis of intestinal mucosa atrophy.

Efficacy and Safety of Synbiotics in Patients Undergoing Autologous Hematopoietic Stem Cell Transplantation: A Randomized, Double-blinded, Placebo-controlled Pilot Study

Objective High-dose chemotherapy with autologous hematopoietic stem cell transplantation (auto-HSCT) is an effective treatment option for relapsed and refractory aggressive malignant lymphoma. However, patients frequently experience treatment-induced gastrointestinal symptoms. Synbiotics, including live microorganisms and nondigestible food ingredients, reportedly ameliorate chemotherapy-induced mucosal damage. In this study, we assessed the efficacy and safety of synbiotics in patients undergoing auto-HSCT. Methods This randomized, double-blinded study included patients with malignant lymphoma eligible for auto-HSCT. The patients were randomly assigned to either a synbiotic group receiving Bifidobacterium longum (BB536) and guar gum or a placebo group receiving a placebo containing dextrin. The supplements were administered twice daily from the start of conditioning chemotherapy up to 28 days after auto-HSCT. The primary endpoint was the duration of total parenteral nutrition (TPN). Results In total, 12 patients were included and randomized. The median duration of TPN was 15 (range, 12-33) days in the synbiotic group and 17.5 (range, 0-32) days in the placebo group. The median duration of grade ≥3 diarrhea was shorter in the synbiotic group than in then placebo group (2.5 vs. 6.5 days), as was the duration of hospital stay (31.5 vs. 43 days). The oral intake and quality of life regarding diarrhea and anorexia improved in the synbiotic group after engraftment. Synbiotic infections, including bacteremia, were not observed. Conclusion Synbiotics may reduce gastrointestinal toxicity, thereby reducing nutritional problems and improving the quality of life of patients undergoing auto-HSCT, without severe adverse events.

Novel developments in the prophylaxis and treatment of acute GVHD

Acute graft-versus-host disease (aGVHD) is a major life-threatening complication after allogeneic hematopoietic cell transplant. Traditional standard prophylaxis for aGVHD has included a calcineurin inhibitor plus an antimetabolite, whereas treatment has relied mainly on corticosteroids, followed by multiple nonstandard second-line options. In the past decade, this basic framework has been reshaped by approval of antithymocyte globulin products, the emergence of posttransplant cyclophosphamide, and recent pivotal trials studying abatacept and vedolizumab for GVHD prophylaxis, whereas ruxolitinib was approved for corticosteroid-refractory aGVHD treatment. Because of this progress, routine acute GVHD prophylaxis and treatment practices are starting to shift, and results of ongoing trials are eagerly awaited. Here, we review recent developments in aGVHD prevention and therapy, along with ongoing and future planned clinical trials in this space, outlining what future goals should be and the limitations of current clinical trial designs and end points.

Graft-versus-host disease: teaching old drugs new tricks at less cost

Graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality after allogeneic stem cell transplantation (SCT). Currently, more patients can receive SCT. This is attributed to the use of reduced intensity regimens and the use of different GVHD prophylaxis that breaks the barrier of human leukocyte antigen, allowing an increase in the donor pool. Once an area with relatively few clinical trial options, there has been an increase in interest in GVHD prophylaxis and treatment, which has led to many US Food and Drug Administration (FDA) approvals. Although there is considerable excitement over novel therapies, many patients may not have access to them due to geographical or other resource constraints. In this review article, we summarize the latest evidence on how we can continue to repurpose drugs for GVHD prophylaxis and treatment. Drugs covered by our review include those that have been FDA approved for other uses for at least 15 years (since 2008); thus, they are likely to have generic equivalents available now or in the near future.

Characterization of the Pharmacokinetic and Pharmacodynamic Profile of Apraglutide, a Glucagon-Like Peptide-2 Analog, in Healthy Volunteers

Apraglutide (FE 203799) is a glucagon-like peptide-2 (GLP-2) analog under development for the treatment of intestinal failure associated with short bowel syndrome (SBS-IF) and graft-versus-host disease (GvHD). Compared with native GLP-2, apraglutide has slower absorption, reduced clearance, and higher protein binding, enabling once-weekly dosing. This study evaluated the pharmacokinetic (PK) and pharmacodynamic (PD) profile of apraglutide in healthy adults. Healthy volunteers were randomized to receive 6 weekly subcutaneous administrations of 1, 5, or 10 mg apraglutide or placebo. PK and citrulline (an enterocyte mass PD marker) samples were collected at multiple time points. Kinetic parameters of apraglutide and citrulline were calculated using noncompartmental analysis; repeated PD measures were analyzed with a mixed model of covariance. A population PK/PD model was developed that also included data from a previous phase 1 study in healthy volunteers. Twenty-four subjects were randomized; 23 received all study drug administrations. Mean estimated apraglutide clearance was 16.5-20.7 l/day, and mean volume of distribution was 55.4-105.0 liters. A dose-dependent increase in citrulline plasma concentration was observed, with 5-mg and 10-mg doses inducing higher citrulline levels than 1-mg doses and placebo. PK/PD analysis showed that weekly 5-mg apraglutide induced the maximal citrulline response. Increased plasma citrulline levels were sustained for 10-17 days after the final apraglutide administration. Apraglutide displays predictable dose-dependent PK and PD profiles, with a 5-mg dose showing significant PD effects. Results suggest that apraglutide has early and enduring effects on enterocyte mass and supports the continued development of weekly subcutaneous apraglutide for SBS-IF and GvHD patient populations. SIGNIFICANCE STATEMENT: Once-weekly subcutaneous apraglutide results in dose-dependent elevations of plasma citrulline (an enterocyte mass pharmacodynamic marker) with parameters suggesting that apraglutide has lasting effects on enterocyte mass and the potential to provide therapeutic benefits. This is the first report of a model relating glucagon-like peptide-2 (GLP-2) agonism and its effects in intestinal mucosa, affording not only the ability to predict pharmacologic effects of GLP-2 analogs but also the exploration of optimal dosing regimens for this drug class across populations with different body weights.

Small bowel transplant - novel indications and recent progress

INTRODUCTION

Advances in the management of intestinal failure have led to a reduction in the number of intestinal transplants. The number of bowel transplants has been mainly stable even though a slight increase has been observed in the last 5 years.

AREAS COVERED

Standard indication includes patients with a reasonable life expectancy. Recent progress can be deduced by the increased number of intestine transplants in adults: this is due to the continuous improvement of 1-year graft survival worldwide (without differences in 3- and 5-year) associated with better abdominal wall closure techniques. This review aims to provide an update on new indications and changes in trends of pediatric and adult intestine transplantation. This analysis, which stretches through the past 5 years, is based on a collection of related manuscripts from PubMed.

EXPERT COMMENTARY

Intestinal transplants should be solely intended for a group of individuals for whom indications for transplantation are clear and both medical and surgical rehabilitations have failed. Nevertheless, many protocols developed over the years have not yet solved the key question represented by the over-immunosuppression. Novel indications and recent progress in the bowel transplant field, minimal yet consistent, represent a pathway to be followed.

Prognostic value of blood biomarkers in steroid-refractory or steroid-dependent acute graft-versus-host disease: a REACH2 analysis

Systemic steroids are the standard first-line treatment for acute graft-versus-host disease (aGVHD), but ∼50% of patients become steroid-refractory or dependent (SR/D). Ruxolitinib is the only Food and Drug Administration- and European Medicines Agency-approved therapy for patients with SR/D aGVHD. In the phase 3 REACH2 trial (NCT02913261), ruxolitinib demonstrated superior efficacy in SR/D aGVHD, with a significantly higher overall response rate (ORR) on day 28, durable ORR on day 56, and longer median overall survival compared with the best available therapy (BAT). Identifying biomarkers and clinical characteristics associated with increased probability of response can guide treatment decisions. In this exploratory analysis of the REACH2 study (first biomarker study), we developed baseline (pretreatment) and day 14 models to identify patient characteristics and biomarkers (12 aGVHD-associated cytokines/chemokines, 6 immune cell types, and 3 inflammatory proteins) before and during treatment, which affected the probability of response at day 28. Treatment with ruxolitinib, conditioning, skin involvement, and age were strongly associated with an increased likelihood of response in the ≥1 model. Lower levels of most aGVHD and immune cell markers at baseline were associated with an increased probability of response. In the day 14 model, levels of aGVHD markers at day 14, rather than changes from baseline, affected the probability of response. For both models, the bias-corrected area under the receiver operating characteristic values (baseline, 0.73; day 14, 0.80) indicated a high level of correspondence between the fitted and actual outcomes. Our results suggest potential prognostic value of selected biomarkers and patient characteristics.

Modulation of stem cell fate in intestinal homeostasis, injury and repair

The mammalian intestinal epithelium constitutes the largest barrier against the external environment and makes flexible responses to various types of stimuli. Epithelial cells are fast-renewed to counteract constant damage and disrupted barrier function to maintain their integrity. The homeostatic repair and regeneration of the intestinal epithelium are governed by the Lgr5⁺ intestinal stem cells (ISCs) located at the base of crypts, which fuel rapid renewal and give rise to the different epithelial cell types. Protracted biological and physicochemical stress may challenge epithelial integrity and the function of ISCs. The field of ISCs is thus of interest for complete mucosal healing, given its relevance to diseases of intestinal injury and inflammation such as inflammatory bowel diseases. Here, we review the current understanding of the signals and mechanisms that control homeostasis and regeneration of the intestinal epithelium. We focus on recent insights into the intrinsic and extrinsic elements involved in the process of intestinal homeostasis, injury, and repair, which fine-tune the balance between self-renewal and cell fate specification in ISCs. Deciphering the regulatory machinery that modulates stem cell fate would aid in the development of novel therapeutics that facilitate mucosal healing and restore epithelial barrier function.

Post-Marketing Use of Teduglutide in a Large Cohort of Adults with Short Bowel Syndrome-Associated Chronic Intestinal Failure: Evolution and Outcomes

Teduglutide, a GLP-2 analogue, has been available in France since 2015 to treat short-bowel-syndrome (SBS)-associated chronic intestinal failure (CIF) but it remains very expensive. No real-life data on the number of potential candidates are available. The aim of this real-life study was to assess teduglutide initiation and outcomes in SBS-CIF patients. All SBS-CIF patients cared for in an expert home parenteral support (PS) center between 2015 and 2020 were retrospectively included. Patients were divided into two subpopulations: prevalent patients, already cared for in the center before 2015, and incident patients, whose follow-up started between 2015 and 2020. A total of 331 SBS-CIF patients were included in the study (156 prevalent and 175 incident patients). Teduglutide was initiated in 56 patients (16.9% of the cohort); in 27.9% of prevalent patients and in 8.0% of incident patients, with a mean annual rate of 4.3% and 2.5%, respectively. Teduglutide allowed a reduction in the PS volume by 60% (IQR: 40-100), with a significantly higher reduction in incident versus prevalent patients (p = 0.02). The two- and five-year treatment retention rates were 82% and 64%. Among untreated patients, 50 (18.2%) were considered ineligible for teduglutide for non-medical reasons. More than 25% of prevalent SBS patients were treated with teduglutide compared to 8% of incident patients. The treatment retention rate was >80% at 2 years, which could be explained by a careful selection of patients. Furthermore, this real-life study confirmed the long-term efficacy of teduglutide and showed a better response to teduglutide in incident patients, suggesting a benefit in early treatment.

Effects of hormones on intestinal stem cells

The maintenance of intestinal renewal and repair mainly depends on intestinal stem cells (ISCs), which can also contribute to the growth of intestinal tumours. Hormones, which are vital signalling agents in the body, have various effects on the growth and replacement of intestinal stem cells. This review summarises recent progress in the identification of hormones associated with intestinal stem cells. Several hormones, including thyroid hormone, glucagon-like peptide-2, androgens, insulin, leptin, growth hormone, corticotropin-releasing hormone and progastrin, promote the development of intestinal stem cells. However, somatostatin and melatonin are two hormones that prevent the proliferation of intestinal stem cells. Therefore, new therapeutic targets for the diagnosis and treatment of intestinal illnesses can be identified by examining the impact of hormones on intestinal stem cells.

Pathophysiology of gastrointestinal acute graft-versus-host disease and the potential role of glucagon-like peptide 2

Acute graft-versus-host disease (aGVHD) is a life-threatening complication after allogeneic haematopoietic cell transplantation, with gastrointestinal (GI) tract involvement (GI aGVHD) being one of the leading causes of morbidity and mortality. Whilst systemic steroids are the standard first-line treatment for aGVHD, approximately 50% of patients become steroid refractory (SR), which is associated with poor outcomes. Existing options for SR-GVHD are limited, and there is a significant unmet need for new non-immunosuppressive treatment approaches in patients with GI aGVHD. Here, we review newer concepts in the pathogenesis of GI aGVHD and present the evidence for the role of glucagon-like peptide 2 (GLP-2) in maintaining and protecting GI epithelial cells, including the enterocytes, intestinal stem cells and Paneth cells, which are direct targets of aGVHD. Finally, we discuss the therapeutic rationale for GLP-2 treatment as a tissue regeneration approach and the potential use of the novel GLP-2 analogue apraglutide as an adjunctive treatment for GI aGVHD.

Multifaceted involvements of Paneth cells in various diseases within intestine and systemically

Serving as the guardians of small intestine, Paneth cells (PCs) play an important role in intestinal homeostasis maintenance. Although PCs uniquely exist in intestine under homeostasis, the dysfunction of PCs is involved in various diseases not only in intestine but also in extraintestinal organs, suggesting the systemic importance of PCs. The mechanisms under the participation of PCs in these diseases are multiple as well. The involvements of PCs are mostly characterized by limiting intestinal bacterial translocation in necrotizing enterocolitis, liver disease, acute pancreatitis and graft-vs-host disease. Risk genes in PCs render intestine susceptible to Crohn’s disease. In intestinal infection, different pathogens induce varied responses in PCs, and toll-like receptor ligands on bacterial surface trigger the degranulation of PCs. The increased level of bile acid dramatically impairs PCs in obesity. PCs can inhibit virus entry and promote intestinal regeneration to alleviate COVID-19. On the contrary, abundant IL-17A in PCs aggravates multi-organ injury in ischemia/reperfusion. The pro-angiogenic effect of PCs aggravates the severity of portal hypertension. Therapeutic strategies targeting PCs mainly include PC protection, PC-derived inflammatory cytokine elimination, and substituting AMP treatment. In this review, we discuss the influence and importance of Paneth cells in both intestinal and extraintestinal diseases as reported so far, as well as the potential therapeutic strategies targeting PCs.

Role of Gut Microbiota and Oxidative Stress in the Progression of Transplant-Related Complications following Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation (HSCT), also known as bone marrow transplantation, has curative potential for various hematologic malignancies but is associated with risks such as graft-versus-host disease (GvHD), severe bloodstream infection, viral pneumonia, idiopathic pneumonia syndrome (IPS), lung fibrosis, and sinusoidal obstruction syndrome (SOS), which severely deteriorate clinical outcomes and limit the wide application of HSCT. Recent research has provided important insights into the effects of gut microbiota and oxidative stress (OS) on HSCT complications. Therefore, based on recent studies, we describe intestinal dysbiosis and OS in patients with HSCT and review recent molecular findings underlying the causal relationships of gut microbiota, OS, and transplant-related complications, focusing particularly on the involvement of gut microbiota-mediated OS in postengraftment complications. Also, we discuss the use of antioxidative and anti-inflammatory probiotics to manipulate gut microbiota and OS, which have been associated with promising effects in improving HSCT outcomes.

Recent advances in graft-versus-host disease

Acute and chronic graft-versus-host disease (GVHD) continue to present a significant challenge to physicians, accounting for considerable haematopoietic stem cell transplant (HSCT)-related morbidity and mortality, particularly those patients with steroid-refractory disease. In this review, we discuss recent advances in understanding the underlying pathophysiology, prevention and management of acute and chronic GVHD. Barriers to progress include the difficulty in obtaining high-quality evidence with sufficient patient numbers to identify optimal preventative and treatment strategies, with the heterogeneity of multiple patient, donor, graft and transplant-related factors, in addition to limited availability of human tissue to study the underlying pathophysiology, particularly in steroid-refractory disease. Continued collaborative efforts to improve our understanding of the pathophysiology involved, particularly in steroid-refractory disease, identification of biomarkers to permit risk stratification, and further well-designed randomised clinical trials are essential to help physicians determine optimal GVHD preventative and treatment strategies for each individual patient.

Allogeneic hematopoietic cell transplantation, the microbiome, and graft-versus-host disease

Many patients with hematological malignancies, such as acute myeloid leukemia, receive an allogeneic hematopoietic cell transplantation (HCT) to cure their underlying condition. Allogeneic HCT recipients are exposed to various elements during the pre-, peri- and post-transplant period that can disrupt intestinal microbiota, including chemo- and radiotherapy, antibiotics, and dietary changes. The dysbiotic post-HCT microbiome is characterized by low fecal microbial diversity, loss of anaerobic commensals, and intestinal domination, particularly by Enterococcus species, and is associated with poor transplant outcomes. Graft-versus-host disease (GvHD) is a frequent complication of allogeneic HCT caused by immunologic disparity between donor and host cells and results in tissue damage and inflammation. Microbiota injury is particularly pronounced in allogeneic HCT recipients who go on to develop GvHD. At present, manipulation of the microbiome for example, via dietary interventions, antibiotic stewardship, prebiotics, probiotics, or fecal microbiota transplantation, is widely being explored to prevent or treat gastrointestinal GvHD. This review discusses current insights into the role of the microbiome in GvHD pathogenesis and summarizes interventions to prevent and treat microbiota injury.

Milestones in acute GVHD pathophysiology

In the past 65 years, over 25 000 referenced articles have been published on graft-versus-host disease (GVHD). Although this included clinically orientated papers or publications on chronic GVHD, the conservative estimate of scientific publications still contains several thousands of documents on the pathophysiology of acute GVHD. Thus, summarizing what we believe are prominent publications that can be considered milestones in our knowledge of this disease is a challenging and inherently biased task. Here we review from a historical perspective what can be regarded as publications that have made the field move forward. We also included several references of reviews on aspects we could not cover in detail.

Assessment of the Gut Microbiota during Juice Fasting with and without Inulin Supplementation: A Feasibility Study in Healthy Volunteers

Prebiotic inulin consumption provides health benefits to the host and has also been associated with a reduction in hunger cravings. We conducted a pilot crossover study to investigate the feasibility of a juice fasting intervention with and without inulin supplementation. We also examined trends of how the microbial community in the human gut adapts to juice fasting as well as to inulin intake during juice fasting. Six healthy volunteers were fasting for three consecutive days consuming a total of 300 kcal daily provided by vegetable juices, framed by two days with a total daily calorie intake of 800 kcal, respectively. During one fasting period, participants consumed additionally 24 g of inulin daily. Stool samples were collected for the analysis of the microbial composition using 16S rRNA gene sequencing. Although no significant uniform changes were observed on the microbiome, quantitative changes in the microbial composition suggest a stronger decrease in alpha-diversity after fasting compared to the fasting intervention with additional inulin intake. The intake of inulin did not affect compliance for the fasting intervention but appeared to increase relative abundance of Bifidobacteria in participants who tolerated it well. Further studies with a larger sample size to overcome inter-individual microbiota differences are warranted to verify our observations.

Dietary supplementation of squalene increases the growth performance of early-weaned piglets by improving gut microbiota, intestinal barrier, and blood antioxidant capacity

This study aimed to investigate the effects of dietary squalene (SQ) supplementation on the growth performance of early-weaned piglets. Twenty early-weaned piglets were randomly divided into two groups, the squalene group (SQ) and the control group (CON). The CON group was fed a basal diet, and the SQ group was fed a basal diet with 250 mg/kg squalene. The feeding period lasted 21 days. The results showed that SQ significantly increased the final body weight (FWB, P < 0.05), average daily gain (ADG, P < 0.05), and average daily feed intake (ADFI, P < 0.05) and significantly decreased the F/G ratio (feed intake/gain, P < 0.05) and diarrhea index (DI, P < 0.05). In terms of blood biochemical indicators, SQ significantly increased anti-inflammatory factors such as transforming growth factor-β (TGF-β, P < 0.001), interleukin-10 (IL-10, P < 0.001), and interferon-γ (IFN-γ, P < 0.01), and decreased pro-inflammatory factors such as tumor necrosis factor-α (TFN-α, P < 0.001) and interleukin-6 (IL-6, P < 0.001). Furthermore, SQ significantly increased blood antioxidant indexes (P < 0.001) such as superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and total antioxidant capacity (T-AOC) and significantly decreased the level of malondialdehyde (MDA) (P < 0.001). The villus height (P < 0.001) and V/C ratio (villus height/crypt depth, P < 0.001) of the jejunum were significantly increased in the SQ group, while the crypt depth (P < 0.01) was decreased compared to the CON group. The intestinal permeability indexes, namely diamine oxidase (DAO), D-lactic acid (D-Lac), regenerative insulin-derived protein 3 (REG-3), and FITC-Dextran 4 (FD₄), significantly decreased the concentrations in the treatment group (P < 0.001), and the antioxidant indexes of the jejunum, such as SOD, GSH-Px, CAT, and MDA, were improved by adding SQ. The qPCR results showed that adding SQ could significantly increase the mRNA expression of jejunal tight-junction proteins, such as zonula occludens-1 (ZO-1, P < 0.001), Occludin (P < 0.001), Claudin (P < 0.001), glucagon-like peptide-2 (GLP-2, P < 0.001), and insulin-like growth factor-1 (IGF-1, P < 0.001). Then, we used Western blotting experiments to further confirm the qPCR results. In addition, it was found that adding SQ increased the abundance of beneficial bacteria such as Gemmiger (P < 0.01) and decreased the abundance of harmful bacteria such as Alloprevotella (P < 0.05), Desulfovibrio (P < 0.05), and Barnesiella (P < 0.05). It was interesting that there was a very close correlation among the fecal microbes, growth performance parameters, intestinal barrier, and blood biochemical indicators. In conclusion, the data suggest that SQ supplementation could effectively improve the growth performance of early-weaned piglets by improving the gut microbiota, intestinal barrier, and antioxidant capacity of the blood and jejunal mucosa.

GLP-1 and GLP-2 Orchestrate Intestine Integrity, Gut Microbiota, and Immune System Crosstalk

The intestine represents the body's largest interface between internal organs and external environments except for its nutrient and fluid absorption functions. It has the ability to sense numerous endogenous and exogenous signals from both apical and basolateral surfaces and respond through endocrine and neuronal signaling to maintain metabolic homeostasis and energy expenditure. The intestine also harbours the largest population of microbes that interact with the host to maintain human health and diseases. Furthermore, the gut is known as the largest endocrine gland, secreting over 100 peptides and other molecules that act as signaling molecules to regulate human nutrition and physiology. Among these gut-derived hormones, glucagon-like peptide 1 (GLP-1) and -2 have received the most attention due to their critical role in intestinal function and food absorption as well as their application as key drug targets. In this review, we highlight the current state of the literature that has brought into light the importance of GLP-1 and GLP-2 in orchestrating intestine-microbiota-immune system crosstalk to maintain intestinal barrier integrity, inflammation, and metabolic homeostasis.

Growth differentiation factor-15 as a biomarker of atherosclerotic coronary plaque: Value in people living with and without HIV

Background

Increased rates of cardiovascular diseases (CVD) and larger subclinical high-risk coronary plaques in coronary CT angiography have been observed in people living with HIV (PLWH) treated with antiretroviral therapy (ART) compared to HIV-uninfected people. Growth differentiation factor-15 (GDF-15) is a cytokine emerging as an optimal marker for CVD in the general population.

Methods

We cross-sectionally analyzed plasma of 95 PLWH on ART and 52 controls. We measured GDF-15, fibroblast growth factor-21 (FGF-21), glucagon-like peptide-2 (GLP-2), soluble urokinase plasminogen activator receptor (suPAR), CRP, and anti-CMV and anti-EBV IgG levels. All participants had no clinical CVD and underwent coronary CT angiography with the 3D reconstruction of coronary artery atherosclerotic plaques. Total plaque volume (TPV) and low attenuation plaque volume (LAPV, defined as density &lt;30 Hounsfield Units) were calculated (mm3).

Results

In both PLWH and controls, GDF-15 levels were increased in participants with presence of coronary plaque vs. without (p = 0.04 and p &lt; 0.001, respectively) and correlated with TPV (r = 0.27, p = 0.009 and r = 0.62, p &lt; 0.001, respectively) and LAPV (r = 0.28, p = 0.008, r = 0.60, p &lt; 0.001, respectively). However, in a multivariate model, GDF-15 was independently associated with LAPV in controls only (adjusted OR 35.1, p = 0.04) and not in PLWH, mainly due to confounding by smoking. Other markers were not independently associated with plaque volume, except for anti-EBV IgGs in controls (adjusted OR 3.51, p = 0.02).

Conclusion

In PLWH, GDF-15 and smoking seemed to synergistically contribute to coronary plaque volume. Conversely, increased GDF-15 levels were associated with the presence of coronary artery plaques in people without HIV, independently of CV risk factors.

Therapy response of glucocorticoid-refractory acute GVHD of the lower intestinal tract

Acute graft-versus-host disease (aGVHD) is a major life-threatening complication of allogeneic hematopoietic cell transplantation. While most studies report therapy-response of aGVHD including a cumulative grade of skin, liver and intestinal tract manifestations, there is a lack of information specifically on lower gastrointestinal tract aGVHD (GI-GVHD) therapy-response, which is highly relevant in light of novel therapies that target intestinal regeneration such as IL-22, R-spondin or GLP-2. Here we retrospectively analyzed patients who developed GI-GVHD over a 6-year period. A total of 144 patients developed GI-GVHD and 82 (57%) were resistant to glucocorticoid-therapy (SR). The most commonly used second-line therapy was ruxolitinib (74%). Overall and complete response (CR) to ruxolitinib on day 28 were 44.5% and 13%, respectively. SR-GVHD patients experienced a lower 5-year overall survival (OS) (34.8 vs 53.3%, p = 0.0014) and higher incidence of 12-months non-relapse-mortality (39.2 vs 14.3%, p = 0.016) compared to glucocorticoid-sensitive patients. SR-GI-GVHD patients, that achieved a CR on day 28 after ruxolitinib start, experienced a higher OS compared to non-CR patients (p = 0.04). These findings indicate that therapy response of SR-GI-GVHD to different immunosuppressive approaches is still low, and that novel therapies specifically aiming at enhanced intestinal regeneration should be tested in clinical trials.

A Promising Insight: The Potential Influence and Therapeutic Value of the Gut Microbiota in GI GVHD

Allogeneic hematopoietic cell transplantation (allo-HSCT) is a reconstruction process of hematopoietic and immune functions that can be curative in patients with hematologic malignancies, but it carries risks of graft-versus-host disease (GVHD), thrombotic microangiopathy (TMA), Epstein–Barr virus (EBV) infection, cytomegalovirus infection, secondary hemophagocytic lymphohistiocytosis (sHLH), macrophage activation syndrome (MAS), bronchiolitis obliterans, and posterior reversible encephalopathy syndrome (PRES). Gastrointestinal graft-versus-host disease (GI GVHD), a common complication of allo-HSCT, is one of the leading causes of transplant-related death because of its high treatment difficulty, which is affected by preimplantation, antibiotic use, dietary changes, and intestinal inflammation. At present, human trials and animal studies have proven that a decrease in intestinal bacterial diversity is associated with the occurrence of GI GVHD. Metabolites produced by intestinal bacteria, such as lipopolysaccharides, short-chain fatty acids, and secondary bile acids, can affect the development of GVHD through direct or indirect interactions with immune cells. The targeted damage of GVHD on intestinal stem cells (ISCs) and Paneth cells results in intestinal dysbiosis or dysbacteriosis. Based on the effect of microbiota metabolites on the gastrointestinal tract, the clinical treatment of GI GVHD can be further optimized. In this review, we describe the mechanisms of GI GVHD and the damage it causes to intestinal cells and we summarize recent studies on the relationship between intestinal microbiota and GVHD in the gastrointestinal tract, highlighting the role of intestinal microbiota metabolites in GI GVHD. We hope to elucidate strategies for immunomodulatory combined microbiota targeting in the clinical treatment of GI GVHD.

An updated overview of glucagon-like peptide-2 analog trophic therapy for short bowel syndrome in adults

Short bowel syndrome (SBS) is a clinical condition characterized by a failure to achieve optimal intestinal adaptation, which is necessary to maintain oral/enteral autonomy. At present, the treatment options for SBS are primarily intestinal replacement and rehabilitation. Intestinal rehabilitation mainly includes non-transplantation surgery and intestinal rehabilitation measures. In recent years, intestinal rehabilitation in patients with SBS using nutritional intestinal hormones, especially glucagon-like peptide-2 analogs, has made great progress. Many high-quality studies have provided evidence-based medical findings to support the development of clinical guidelines. This article reviews the latest research advancements regarding the use of glucagon-like peptide-2 analogs (teduglutide, glepaglutide, and apraglutide) in the treatment of SBS.

GVHD, IBD and primary immunodeficiencies: The gut as a target of immunopathology resulting from impaired immunity

The intestinal tract is the largest immunological organ in the body and has a central function of regulating local immune responses, as the intestinal epithelial barrier is a location where the immune system interacts with the gut microbiome including bacteria, fungi and viruses. Impaired immunity in the intestinal tract can lead to immunopathology, which manifests in different diseases such as inflammatory bowel disease (IBD) or intestinal graft-versus-host disease (GVHD). A disturbed communication between epithelial cells, immune cells and microbiome will shape pathogenic immune responses to antigens, which need to be counterbalanced by tolerogenic mechanisms and repair mechanisms. Here, we review how impaired intestinal immune function leads to immunopathology with a specific focus on innate immune cells, the role of the microbiome and the resulting clinical manifestations including intestinal GVHD, IBD and enteropathy in primary immunodeficiency. This article is protected by copyright. All rights reserved.

Effects of Fermented Vegetable Consumption on Human Gut Microbiome Diversity—A Pilot Study

The interest in fermented food products has been increasing in recent years. Details about their microbial composition and the effects of their consumption on the human gut microbiome are of particular interest. However, evidence regarding their potential to increase gut microbial diversity, a measure likely associated with health, is lacking. To address this, we analyzed the microbial composition of commercially available fermented vegetables using 16S rRNA sequencing. We also conducted a pilot study to assess the feasibility of studying the effects of regular consumption of fermented vegetables on the gut microbiome. Six healthy male volunteers participated in a randomized crossover trial, with two two-week intervention phases. Volunteers consumed 150 g/d of either sauerkraut or a variety of six different commercially available fermented vegetables. This study is registered at the German Clinical Trials Register (DRKS-ID: DRKS00014840). Lactobacillales was the dominant family in all fermented vegetables studied. However, the alpha diversity, richness and evenness of the microbiota differed substantially among the different products. The number of species per product varied between 20 and 95. After consumption of both sauerkraut and the selection of fermented vegetables, we observed a slight increase in alpha diversity. Specifically, the amount of the genus Prevotella decreased while the amount of Bacteroides increased after both interventions. However, these initial observations need to be confirmed in larger studies. This pilot study demonstrates the feasibility of this type of research.

WR-GLP2, a glucagon-like peptide 2 from hybrid crucian carp that protects intestinal mucosal barrier and inhibits bacterial infection

Glucagon-like peptide 2 (GLP2) is a proglucagon-derived peptide produced by intestinal enteroendocrine L-cells. The main biological actions of GLP2 in mammals are related to regulating energy absorption and maintaining the morphology, integrity of intestinal mucosa. However, the in vivo function of fish GLP2 in intestinal barrier and immune defense is essentially unknown. With an aim to elucidate the antimicrobial mechanism of GLP2 in fish, we in this study examined the function of GLP2 from hybrid crucian carp. Hybrid crucian carp GLP2 (WR-GLP2) possesses the conserved glucagon like hormones 2 domain. WR-GLP2 is mainly expressed in the intestine and is significantly upregulated after Aeromonas hydrophila infection. AB-PAS staining analysis showed WR-GLP2 significantly increased the number of goblet cells in intestine. WR-GLP2 induced significant inductions in the expression of the antimicrobial molecules (MUC2, Lyzl-1, Hepcidin-1 and LEAP-2) and tight junctions (ZO-1, Occludin and Claudin-4). In addition, WR-GLP2 significantly alleviated the intestinal apoptosis, thereby enhancing host's resistance against Aeromonas hydrophila infection. Together these results indicate that WR-GLP2 is involved in intestinal mucosal barrier and immune defense against pathogen infection.

Steroid-Refractory Gut Graft-Versus-Host Disease: What We Have Learned From Basic Immunology and Experimental Mouse Model

Intestinal graft-versus-host disease (Gut-GVHD) is one of the major causes of mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). While systemic glucocorticoids (GCs) comprise the first-line treatment option, the response rate for GCs varies from 30% to 50%. The prognosis for patients with steroid-refractory acute Gut-GVHD (SR-Gut-aGVHD) remains dismal. The mechanisms underlying steroid resistance are unclear, and apart from ruxolitinib, there are no approved treatments for SR-Gut-aGVHD. In this review, we provide an overview of the current biological understanding of experimental SR-Gut-aGVHD pathogenesis, the advanced technology that can be applied to the human SR-Gut-aGVHD studies, and the potential novel therapeutic options for patients with SR-Gut-aGVHD.