Citrulline: a potentially simple quantitative marker of intestinal epithelial damage following myeloablative therapy

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.

Self-emulsifying drug delivery systems (SEDDS) disrupt the gut microbiota and trigger an intestinal inflammatory response in rats

Self-emulsifying drug delivery systems (i.e. SEDDS, SMEDDS and SNEDDS) are widely employed as solubility and bioavailability enhancing formulation strategies for poorly water-soluble drugs. Despite the capacity for SEDDS to effectively facilitate oral drug absorption, tolerability concerns exist due to the capacity for high concentrations of surfactants (typically present within SEDDS) to induce gastrointestinal toxicity and mucosal irritation. With new knowledge surrounding the role of the gut microbiota in modulating intestinal inflammation and mucosal injury, there is a clear need to determine the impact of SEDDS on the gut microbiota. The current study is the first of its kind to demonstrate the detrimental impact of SEDDS on the gut microbiota of Sprague-Dawley rats, following daily oral administration (100 mg/kg) for 21 days. SEDDS comprising a lipid phase (i.e. Type I, II and III formulations according to the Lipid Formulation Classification Scheme) induced significant changes to the composition and diversity of the gut microbiota, evidenced through a reduction in operational taxonomic units (OTUs) and alpha diversity (Shannon's index), along with statistically significant shifts in beta diversity (according to PERMANOVA of multi-dimensional Bray-Curtis plots). Key signatures of gut microbiota dysbiosis correlated with the increased expression of pro-inflammatory cytokines within the jejunum, while mucosal injury was characterised by significant reductions in plasma citrulline levels, a validated biomarker of enterocyte mass and mucosal barrier integrity. These findings have potential clinical ramifications for chronically administered drugs that are formulated with SEDDS and stresses the need for further studies that investigate dose-dependent effects of SEDDS on the gastrointestinal microenvironment in a clinical setting.

A dynamic model of the intestinal epithelium integrates multiple sources of preclinical data and enables clinical translation of drug-induced toxicity

We have built a quantitative systems toxicology modeling framework focused on the early prediction of oncotherapeutic-induced clinical intestinal adverse effects. The model describes stem and progenitor cell dynamics in the small intestinal epithelium and integrates heterogeneous epithelial-related processes, such as transcriptional profiles, citrulline kinetics, and probability of diarrhea. We fitted a mouse-specific version of the model to quantify doxorubicin and 5-fluorouracil (5-FU)-induced toxicity, which included pharmacokinetics and 5-FU metabolism and assumed that both drugs led to cell cycle arrest and apoptosis in stem cells and proliferative progenitors. The model successfully recapitulated observations in mice regarding dose-dependent disruption of proliferation which could lead to villus shortening, decrease of circulating citrulline, increased diarrhea risk, and transcriptional induction of the p53 pathway. Using a human-specific epithelial model, we translated the cytotoxic activity of doxorubicin and 5-FU quantified in mice into human intestinal injury and predicted with accuracy clinical diarrhea incidence. However, for gefitinib, a specific-molecularly targeted therapy, the mice failed to reproduce epithelial toxicity at exposures much higher than those associated with clinical diarrhea. This indicates that, regardless of the translational modeling approach, preclinical experimental settings have to be suitable to quantify drug-induced clinical toxicity with precision at the structural scale of the model. Our work demonstrates the usefulness of translational models at early stages of the drug development pipeline to predict clinical toxicity and highlights the importance of understanding cross-settings differences in toxicity when building these approaches.

Exposure of anti-infective drugs and the dynamic changes of the gut microbiota during gastrointestinal mucositis in autologous stem cell transplant patients: a pilot study

Gastrointestinal mucositis could potentially compromise drug absorption due to functional loss of mucosa and other pathophysiological changes in the gastrointestinal microenvironment. Little is known about this effect on commonly used anti-infectives. This study aimed to explore the association between different stages of gastrointestinal mucositis, drug exposure, and gut microbiota. A prospective, observational pilot study was performed in HSCT patients aged ≥ 18 years receiving anti-infectives orally. Left-over blood samples and fecal swabs were collected from routine clinical care until 14 days after HSCT to analyze drug and citrulline concentrations and to determine the composition of the gut microbiota. 21 patients with a median age of 58 (interquartile range 54-64) years were included with 252 citrulline, 155 ciprofloxacin, 139 fluconazole, and 76 acyclovir concentrations and 48 fecal swabs obtained. Severe gastrointestinal mucositis was observed in all patients. Due to limited data correlation analysis was not done for valacyclovir and fluconazole, however we did observe a weak correlation between ciprofloxacin and citrulline concentrations. This could suggest that underexposure of ciprofloxacin can occur during severe mucositis. A follow-up study using frequent sampling rather than the use of left-over would be required to investigate the relationship between gastrointestinal mucositis, drug exposure, and gut microbiome.

Increased Intestinal Permeability and Stool Zonulin, Calprotectin and Beta-Defensin-2 Concentrations in Allogenic Hematopoietic Cell Transplantation Recipients

Significant progress has been made in understanding the connection between intestinal barrier function and allogenic hematopoietic cell transplantation (allo-HCT) recipients' outcomes. The purpose of this study was to further evaluate gut barrier permeability and other potential intestinal barrier disruption markers in the allo-HCT setting. Fifty-one patients were enrolled in the study. Intestinal permeability was assessed with the sugar absorption test and faecal concentrations of the zonulin, calprotectin and beta-defensin-2 levels in the peri-transplantation period. Most patients undergoing allo-HCT in our department had a disrupted intestinal barrier at the baseline, which was associated with older age and higher Hematopoietic Cell Transplantation-specific Comorbidity Index (HCT-CI). Regardless of this, we observed a further increase in gut barrier permeability after allo-HCT in most patients. However, there was no association between permeability assay and other markers (zonulin, calprotectin and beta-defensin-2). Patients with acute GVHD had significantly higher median calprotectin concentrations after allo-HCT compared with the patients without this complication. Our findings indicate that gut barrier damage develops prior to allo-HCT with progression after the procedure and precedes further complications, but did not prove other markers to be useful surrogates of intestinal permeability.

Compilation of longitudinal gut microbiome, serum metabolome, and clinical data in acute myeloid leukemia

Induction chemotherapy for patients with acute myeloid leukemia (AML) is a unique clinical scenario. These patients spend several weeks in the hospital, receiving multiple antibiotics, experiencing gastrointestinal mucosal damage, and suffering severe impairments in their immune system and nutrition. These factors cause major disruptions to the gut microbiota to a level rarely seen in other clinical conditions. Thus, the study of the gut microbiota in these patients can reveal novel aspects of microbiota-host relationships. When combined with the circulating metabolome, such studies could shed light on gut microbiota contribution to circulating metabolites. Collectively, gut microbiota and circulating metabolome are known to regulate host physiology. We have previously deposited amplicon sequences from 566 fecal samples from 68 AML patients. Here, we provide sample-level details and a link, using de-identified patient IDs, to additional data including serum metabolomics (260 samples from 36 patients) and clinical metadata. The detailed information provided enables comprehensive multi-omics analysis. We validate the technical quality of these data through 3 examples and demonstrate a method for integrated analysis.

Supporting the gastrointestinal microenvironment during high-dose chemotherapy and stem cell transplantation by inhibiting IL-1 signaling with anakinra

High-dose chemotherapy causes intestinal inflammation and subsequent breakdown of the mucosal barrier, permitting translocation of enteric pathogens, clinically manifesting as fever. Antibiotics are mainstay for controlling these complications, however, they are increasingly recognized for their detrimental effects, including antimicrobial resistance and dysbiosis. Here, we show that mucosal barrier injury induced by the mucotoxic chemotherapeutic agent, high-dose melphalan (HDM), is characterized by hyper-active IL-1b/CXCL1/neutrophil signaling. Inhibition of this pathway with IL-1RA, anakinra, minimized the duration and intensity of mucosal barrier injury and accompanying clinical symptoms, including diarrhea, weight loss and fever in rats. 16S analysis of fecal microbiome demonstrated a more stable composition in rats receiving anakinra, with reduced pathogen expansion. In parallel, we report through Phase IIA investigation that anakinra is safe in stem cell transplant patients with multiple myeloma after HDM. Ramping-up anakinra (100–300 mg administered intravenously for 15 days) did not cause any adverse events or dose limiting toxicities, nor did it change time to neutrophil recovery. Our results reinforce that strengthening the mucosal barrier may be an effective supportive care strategy to mitigate local and systemic clinical consequences of HDM. We are now conducting a Phase IIB multicenter, placebo-controlled, double-blinded trial to assess clinical efficacy of anakinra (AFFECT-2).

Trial registration: ClinicalTrials.gov identifier: NCT03233776.

Decreased Plasma Level of Cytokeratin 20 (KRT20) Is Indicative of the Emergence and Severity of Acute GvHD Irrespective to the Type of Organ Involvement

Accurate risk prediction of acute graft versus host disease (aGvHD) is currently an unmet clinical need. This study sought to analyze whether three plasma proteins expressed in a largely skin- and gut-restricted manner would be affected by the development of acute cutaneous and gastrointestinal aGvHD. The diagnostic sensitivity, specificity, and prognostic value of plasma cytokeratin-15 (KRT15) cytokeratin-20 (KRT20), and occludin (OCLN) were evaluated in a discovery and a validation cohort using ELISA in comparison with elafin (PI3) and regenerating family member 3 alpha (REG3A), two established markers of skin- and gut aGvHD. The discovery cohort (n = 39) revealed that at the time of diagnosis, plasma KRT20 showed a progressive decrease from unaffected individuals to patients with single-, and patients with multi-organ aGvHD. KRT20 was affected by cutaneous (p = 0.0263) and gastrointestinal aGvHD (p = 0.0242) independently and in an additive manner. Sensitivity and specificity of KRT20 for aGvHD involving both target organs (AUC = 0.852) were comparable to that of PI3 for skin-aGvHD (AUC = 0.708) or that of REG3A for gut-aGvHD (AUC = 0.855). Patient follow-up in the validation cohort (n = 67) corroborated these observations (p < 0.001), and linked low KRT20 to grade 2+ disease (p < 0.001), but failed to confirm low KRT20 as an independent risk factor. These data established a link between low plasma KRT20 levels and moderate to severe aGvHD involving multiple target organs.

Posaconazole bioavailability of the solid oral tablet is reduced during severe intestinal mucositis

OBJECTIVES

To describe the absolute oral bioavailability of the solid oral formulation of posaconazole and the impact of severe intestinal mucositis in haematology patients. Further, to describe posaconazole protein binding in haematology patients.

METHODS

A pharmacokinetic study was performed where patients receiving induction chemotherapy or a haematopoietic cell transplantation were randomized to receive 7 days of intravenous posaconazole therapy followed by 9 days of oral therapy or vice versa. Patients received posaconazole licensed dose until day 12, thereafter a reduced once daily dose of 200 mg was given. At days 7, 12, and 16 blood samples were obtained for pharmacokinetic curves, trough samples were collected on all other days. Total and unbound posaconazole pharmacokinetics were analysed by population pharmacokinetic modelling. The presence of severe intestinal mucositis was assessed by plasma citrulline levels and analysed as a binary covariate using 10 μmol/L as cut-off. Monte Carlo simulations were performed to simulate posaconazole exposure at steady state.

RESULTS

Twenty-three patients were included for analysis with 581 total posaconazole concentrations and 91 paired unbound concentrations. Absolute bioavailability in the final model was estimated at 51.4% (%relative standard error (RSE) 56.5) and 67.6% (%RSE 75.0) in patients with and without severe intestinal mucositis, respectively. Posaconazole unbound fraction was estimated at 2.7% (%RSE 3.9).

CONCLUSIONS

Posaconazole bioavailability is reduced in haematological patients with severe intestinal mucositis, requiring an increase in oral posaconazole dose to 400 mg twice daily on day 1 followed by 400 mg once daily or a switch to intravenous therapy.

Citrulline, Biomarker of Enterocyte Functional Mass and Dietary Supplement. Metabolism, Transport, and Current Evidence for Clinical Use

L-Citrulline is a non-essential but still important amino acid that is released from enterocytes. Because plasma levels are reduced in case of impaired intestinal function, it has become a biomarker to monitor intestinal integrity. Moreover, oxidative stress induces protein citrullination, and antibodies against anti-citrullinated proteins are useful to monitor rheumatoid diseases. Citrullinated histones, however, may even predict a worse outcome in cancer patients. Supplementation of citrulline is better tolerated compared to arginine and might be useful to slightly improve muscle strength or protein balance. The following article shall provide an overview of L-citrulline properties and functions, as well as the current evidence for its use as a biomarker or as a therapeutic supplement.

No effect of deleted in malignant brain tumors 1 deficiency on chemotherapy induced murine intestinal mucositis

Mucositis is a serious adverse effect of chemotherapeutic treatment. During intestinal mucositis, the mucosal barrier is compromised, increasing the risk of severe infections. Mucositis necessitates dose reduction or pauses in treatment, which affect the outcome of the treatment. Deleted in malignant brain tumors 1 (DMBT1) is a secreted scavenger protein with effects on innate immunity and epithelial regeneration. We have previously shown that jejunal DMBT1 expression is increased in piglets during chemotherapeutic treatment. We hypothesized that DMBT1 ameliorates doxorubicin-induced mucositis. Individually-caged Dmbt1^+/+ (WT) and Dmbt1^-/- (KO) female mouse littermates received intraperitoneal injections of either doxorubicin or saline. They were euthanized after three (D3) or seven days (D7). Weight loss was monitored every day, and serum citrulline levels were measured at termination. Intestinal tissue was analyzed for the expression of DMBT1 and proinflammatory cytokines (IL-1β, IL-6, and TNF). Specimens from the small intestines and colon were scored for inflammation and epithelial and mucosal architecture changes. We detected no effect of DMBT1 on weight loss, serum citrulline levels, expression of proinflammatory cytokines, or histologic damage. We detected a significant increase in crypt depth in WT mice compared to that in KO mice on D3. In conclusion, DMBT1 does not affect doxorubicin-induced mucositis in mice.

Antibiotic-induced disruption of the microbiome exacerbates chemotherapy-induced diarrhoea and can be mitigated with autologous faecal microbiota transplantation

BACKGROUND

Chemotherapy is well documented to disrupt the gut microbiome, leading to poor treatment outcomes and a heightened risk of adverse toxicity. Although strong associations exist between its composition and gastrointestinal toxicity, its causal contribution remains unclear. Our inability to move beyond association has limited the development and implementation of microbial-based therapeutics in chemotherapy adjuncts with no clear rationale of how and when to deliver them.

METHODS/RESULTS

Here, we investigate the impact of augmenting the gut microbiome on gastrointestinal toxicity caused by the chemotherapeutic agent, methotrexate (MTX). Faecal microbiome transplantation (FMT) delivered after MTX had no appreciable impact on gastrointestinal toxicity. In contrast, disruption of the microbiome with antibiotics administered before chemotherapy exacerbated gastrointestinal toxicity, impairing mucosal recovery (P < 0.0001) whilst increasing diarrhoea severity (P = 0.0007) and treatment-related mortality (P = 0.0045). Importantly, these detrimental effects were reversed when the microbiome was restored using autologous FMT (P = 0.03), a phenomenon dictated by the uptake and subsequent expansion of Muribaculaceae.

CONCLUSIONS

These are the first data to show that clinically impactful symptoms of gastrointestinal toxicity are dictated by the microbiome and provide a clear rationale for how and when to target the microbiome to mitigate the acute and chronic complications caused by disruption of the gastrointestinal microenvironment. Translation of this new knowledge should focus on stabilising and strengthening the gut microbiome before chemotherapy and developing new microbial approaches to accelerate recovery of the mucosa. By controlling the depth and duration of mucosal injury, secondary consequences of gastrointestinal toxicity may be avoided.

Advances in Intestinal Barrier Preservation and Restoration in the Allogeneic Hematopoietic Cell Transplantation Setting

The intestinal barrier consists of an epithelial lining covered with specialized mucus inhabited by intestinal microbiota. An intact gut barrier ensures a resistance to bacteria and toxins translocation. On the other hand, gut permeability allows the absorption of essential nutrients, fluids and ions. This balance is achieved only by the complex structure and functional characteristics of the intestinal barrier. Allogenic hematopoietic cell transplantation remains the only curative treatment for many hematological diseases, but its application is limited because of possible transplant-related mortality mainly due to graft-versus-host disease and infectious complications. The intestinal barrier has been extensively studied in recent years as the primary site of graft-versus-host disease initiation and propagation. In the present review, we focused on the physiological structure and function of the gut barrier and the evidence of how the disruption of the gut barrier and increased intestinal permeability affects transplant recipients. Finally, therapeutic strategies aiming at intestinal barrier protection with a special focus on microbiome preservation and restoration in the allogenic hematopoietic cell transplantation setting are discussed.

Translational model of melphalan-induced gut toxicity reveals drug-host-microbe interactions that drive tissue injury and fever

PURPOSE

Conditioning therapy with high-dose melphalan (HDM) is associated with a high risk of gut toxicity, fever and infections in haematopoietic stem cell transplant (HSCT) recipients. However, validated preclinical models that adequately reflect clinical features of melphalan-induced toxicity are not available. We therefore aimed to develop a novel preclinical model of melphalan-induced toxicity that reflected well-defined clinical dynamics, as well as to identify targetable mechanisms that drive intestinal injury.

METHODS

Male Wistar rats were treated with 4-8 mg/kg melphalan intravenously. The primary endpoint was plasma citrulline. Secondary endpoints included survival, weight loss, diarrhea, food/water intake, histopathology, body temperature, microbiota composition (16S sequencing) and bacterial translocation.

RESULTS

Melphalan 5 mg/kg caused self-limiting intestinal injury, severe neutropenia and fever while impairing the microbial metabolome, prompting expansion of enteric pathogens. Intestinal inflammation was characterized by infiltration of polymorphic nuclear cells in the acute phases of mucosal injury, driving derangement of intestinal architecture. Ileal atrophy prevented bile acid reabsorption, exacerbating colonic injury via microbiota-dependent mechanisms.

CONCLUSION

We developed a novel translational model of melphalan-induced toxicity, which has excellent homology with the well-known clinical features of HDM transplantation. Application of this model will accelerate fundamental and translational study of melphalan-induced toxicity, with the clinical parallels of this model ensuring a greater likelihood of clinical success.

Radical Hemithoracic Radiotherapy Induces Systemic Metabolomics Changes That Are Associated with the Clinical Outcome of Malignant Pleural Mesothelioma Patients

Simple Summary

Radical hemithoracic radiotherapy represents a promising new advance in the field of radiation oncology and encouraging results have been achieved in the treatment of malignant pleural mesothelioma patients. This study showed that this radiotherapy modality produces significant changes in serum metabolomics profile mainly affecting arginine and polyamine biosynthesis pathways. Interestingly, individual metabolomics alterations were found associated with the clinical overall survival outcome of the radiotherapy treatment. These results highlight metabolomics profile analysis as a powerful prognostic tool useful to better understand the mechanisms underlying the interpatients variability and to identify patients who may receive the best benefit from this specific radiotherapy treatment.

Abstract

Radical hemithoracic radiotherapy (RHRT) represents an advanced therapeutic option able to improve overall survival of malignant pleural mesothelioma patients. This study aims to investigate the systemic effects of this radiotherapy modality on the serum metabolome and their potential implications in determining the individual clinical outcome. Nineteen patients undergoing RHRT at the dose of 50 Gy in 25 fractions were enrolled. Serum targeted metabolomics profiles were investigated at baseline and the end of radiotherapy by liquid chromatography and tandem mass spectrometry. Univariate and multivariate OPLS-DA analyses were applied to study the serum metabolomics changes induced by RHRT while PLS regression analysis to evaluate the association between such changes and overall survival. RHRT was found to affect almost all investigated metabolites classes, in particular, the amino acids citrulline and taurine, the C14, C18:1 and C18:2 acyl-carnitines as well as the unsaturated long chain phosphatidylcholines PC ae 42:5, PC ae 44:5 and PC ae 44:6 were significantly decreased. The enrichment analysis showed arginine metabolism and the polyamine biosynthesis as the most perturbed pathways. Moreover, specific metabolic changes encompassing the amino acids and acyl-carnitines resulted in association with the clinical outcome accounting for about 60% of the interpatients overall survival variability. This study highlighted that RHRT can induce profound systemic metabolic effects some of which may have a significant prognostic value. The integration of metabolomics in the clinical assessment of the malignant pleural mesothelioma could be useful to better identify the patients who can achieve the best benefit from the RHRT treatment.

Anakinra: efficacy in the management of fever during neutropenia and mucositis in autologous stem cell transplantation (AFFECT-2)-study protocol for a multicenter randomized double-blind placebo-controlled trial

Background

Since decades, fever and infections have been the most important complications of intensive chemotherapy and hematopoietic stem cell transplantation (HSCT) in the treatment of hematologic malignancies. Neutropenia has long been considered to be the most important risk factor for these complications. However, recent studies have shown that not neutropenia, but the development of mucositis is the most important cause of these complications. Currently, limited options for the prevention and treatment of mucositis are available, of which most are only supportive. The pro-inflammatory cytokine interleukin-1 (IL-1) plays a crucial role in the pathogenesis of mucositis. Pre-clinical studies of chemotherapy-induced mucositis have shown that recombinant human IL-1 receptor antagonist anakinra significantly ameliorated intestinal mucositis. In our pilot study AFFECT-1, we examined the safety and maximal tolerated dose of anakinra in patients with multiple myeloma, treated with high-dose melphalan (HDM) and autologous HSCT, selecting a dose of 300 mg daily for the phase IIb trial. The aim of the AFFECT-2 study is to determine the efficacy of anakinra in preventing fever during neutropenia (FN) and mucositis in this study population.

Methods/design

A multicenter, randomized, placebo-controlled, double-blind phase IIb trial will be conducted. Ninety patients with multiple myeloma scheduled for treatment with HDM and autologous HSCT will be included. Patients will be randomized between intravenous treatment with anakinra (300 mg) or placebo. Each group will be treated from day − 2 (day of HDM; day 0 is HSCT) up until day + 12. Outcome measures will be assessed at baseline, during admission, at discharge or day + 30, at day + 90, and + 1 year. The primary outcome will be reduction of FN. Secondary outcome measures include mucositis scores, bloodstream infections, citrulline levels, quality of life, and fatigue severity.

Discussion

The AFFECT-2 trial will examine the efficacy of anakinra in the management of fever during neutropenia and mucositis in patients with multiple myeloma treated with HDM and autologous HSCT. The results of this study may provide a new treatment option for these important complications. Also, this study will give us more insight in the pathophysiology of mucositis, including the role of IL-1 and the role of the microbiota in mucositis.

Trial registration

Clinicaltrials.gov NCT04099901. Registered on September 23, 2019. EudraCT: 2018-005046-10.

Integration of Serum Metabolomics into Clinical Assessment to Improve Outcome Prediction of Metastatic Soft Tissue Sarcoma Patients Treated with Trabectedin

Soft tissue sarcomas (STS) are a group of rare and heterogeneous cancers with few diagnostic or prognostic biomarkers. This metabolomics study aimed to identify new serum prognostic biomarkers to improve the prediction of overall survival in patients with metastatic STS. The study enrolled 24 patients treated with the same trabectedin regimen. The baseline serum metabolomics profile, targeted to 68 metabolites encompassing amino acids and bile acids pathways, was quantified by liquid chromatography-tandem mass spectrometry. Correlations between individual metabolomics profiles and overall survival were examined and a risk model to predict survival was built by Cox multivariate regression. The median overall survival of the studied patients was 13.0 months (95% CI, 5.6–23.5). Among all the metabolites investigated, only citrulline and histidine correlated significantly with overall survival. The best Cox risk prediction model obtained integrating metabolomics and clinical data, included citrulline, hemoglobin and patients’ performance status score. It allowed to distinguish patients into a high-risk group with a low median overall survival of 2.1 months and a low- to moderate-risk group with a median overall survival of 19.1 months (p < 0.0001). The results of this metabolomics translation study indicate that citrulline, an amino acid belonging to the arginine metabolism, represents an important metabolic signature that may contribute to explain the high inter-patients overall survival variability of STS patients. The risk prediction model based on baseline serum citrulline, hemoglobin and performance status may represent a new prognostic tool for the early classification of patients with metastatic STS, according to their overall survival expectancy.

Pretransplant Serum Citrulline Predicts Acute Graft-versus-Host Disease

Post-transplant biomarkers of acute graft-versus-host disease (aGVHD) and nonrelapse mortality (NRM) after allogeneic hematopoietic cell transplantation (allo-HCT) have been extensively studied. However, pretransplant biomarkers may provide a greater window of opportunity to intervene. We measured serum biomarkers of various aspects of gut barrier physiology before HCT (median, day -7) and 7 and 28 days post-HCT in 95 consecutive allo-HCT recipients enrolled in an open-label biorepository protocol. Biomarkers included citrulline for total functional enterocyte mass, Reg3a for antibacterial activity of the gut, and intestinal fatty acid binding protein (I-FABP) for enterocyte turnover. Compared to 16 healthy control subjects, we demonstrated that patients came to transplant with abnormal levels of all 3 biomarkers (P < .05), reflecting residual damage from prior chemotherapy. All 3 biomarkers initially declined from pre-HCT to day +7 (more pronounced after myeloablative than reduced-intensive conditioning) followed by a recovery phase and return toward pre-HCT values by day +28. A lower pre-HCT citrulline was independently associated with a higher risk of aGVHD grades II to IV (hazard ratio, 1.32; 95% confidence interval, 1.03 to 1.69; P = .02), and this association was not specific to gut GVHD. The strongest correlate of NRM was a higher level of Reg3a at day +7 (P < .001). I-FABP did not predict transplant outcomes. In conclusion, pre-HCT serum citrulline levels identify patients at high risk for developing aGVHD. Our results suggest that pre-HCT interventions to augment the gut barrier may decrease the risk of aGVHD.

Italian cohort of patients affected by inflammatory bowel disease is characterised by variation in glycerophospholipid, free fatty acids and amino acid levels

BACKGROUND

Inflammatory bowel disease is a group of pathologies characterised by chronic inflammation of the intestine and an unclear aetiology. Its main manifestations are Crohn's disease and ulcerative colitis. Currently, biopsies are the most used diagnostic tests for these diseases and metabolomics could represent a less invasive approach to identify biomarkers of disease presence and progression.

OBJECTIVES

The lipid and the polar metabolite profile of plasma samples of patients affected by inflammatory bowel disease have been compared with healthy individuals with the aim to find their metabolomic differences. Also, a selected sub-set of samples was analysed following solid phase extraction to further characterise differences between pathological samples.

METHODS

A total of 200 plasma samples were analysed using drift tube ion mobility coupled with time of flight mass spectrometry and liquid chromatography for the lipid metabolite profile analysis, while liquid chromatography coupled with triple quadrupole mass spectrometry was used for the polar metabolite profile analysis.

RESULTS

Variations in the lipid profile between inflammatory bowel disease and healthy individuals were highlighted. Phosphatidylcholines, lyso-phosphatidylcholines and fatty acids were significantly changed among pathological samples suggesting changes in phospholipase A₂ and arachidonic acid metabolic pathways. Variations in the levels of cholesteryl esters and glycerophospholipids were also found. Furthermore, a decrease in amino acids levels suggests mucosal damage in inflammatory bowel disease.

CONCLUSIONS

Given good statistical results and predictive power of the model produced in our study, metabolomics can be considered as a valid tool to investigate inflammatory bowel disease.

Association Between Low Plasma Level of Citrulline Before Allogeneic Hematopoietic Cell Transplantation and Severe Gastrointestinal Graft vs Host Disease

BACKGROUND & AIMS

The gastrointestinal form of acute graft vs host disease increases morbidity and mortality following allogeneic hematopoietic cell transplantation. Plasma levels of citrulline, a non-proteinogenic amino acid, indicate functional enterocyte mass. We measured citrulline in patients before allogeneic hematopoietic cell transplantation and investigated its association with incidence and severity of gastrointestinal graft vs host disease.

METHODS

We performed a retrospective study with 191 patients (69 women, 122 men; median age of 52 years) who underwent allogeneic hematopoietic cell transplantation for hematological malignancies at a tertiary center of France from January 2013 through April 2015. Levels of citrulline in plasma samples collected 30 days before graft infusion were measured by high performance liquid chromatography with tandem mass spectrometry. We assigned patients to groups with a high level of citrulline (>26 μmol/L) or low level of citrulline (≤26 μmol/L). The primary outcomes were difference between groups in incidence of stage 2-4 gastrointestinal graft vs host disease, death without hematological disease relapse (non-relapse mortality), relapse of the hematological disease, and overall survival through 2 years after transplantation.

RESULTS

Ninety-six patients (50%) developed acute graft vs host disease and 37 (19%) developed a gastrointestinal form. Among patients with gastrointestinal involvement, 33 patients (89%) had stage 2-4 gastrointestinal graft vs host disease. In univariable analysis, low level of citrulline associated with higher cumulative incidence of stage 2-4 gastrointestinal graft vs host disease, non-relapse mortality, and shorter overall survival. In multivariable analysis, low level of citrulline was the only risk factor independently associated with stage 2-4 gastrointestinal graft vs host disease (hazard ratio, 3.06; 95% CI, 1.37-6.85; P = .007); it also associated with increased non-relapse mortality (hazard ratio, 2.29; 95% CI, 1.24-4.22; P = .008).

CONCLUSIONS

In a retrospective study with 191 patients, we associated a low plasma level of citrulline before allogeneic hematopoietic cell transplantation with a higher risk for stage 2-4 gastrointestinal graft vs host disease and non-relapse mortality. This marker might be used to manage patients before allogeneic hematopoietic cell transplantation.

Animal models of chemotherapy-induced mucositis: translational relevance and challenges

Chemotherapy for cancer patients induces damaging tissue reactions along the epithelium of the gastrointestinal tract (GIT). This chemotherapy-induced mucositis (CIM) is a serious side effect of cytotoxic drugs, and several animal models of CIM have been developed, mainly in rodents and piglets, to help understand the progression of CIM and how to prevent it. Animal models allow highly controlled experimental conditions, detailed organ (e.g., GIT) insights, standardized, clinically relevant treatment regimens, and discovery of new biomarkers. Still, surprisingly few results from animal models have been translated into clinical CIM management and treatments. The results obtained from specific animal models can be difficult to translate to the diverse range of CIM manifestations in patients, which vary according to the antineoplastic drugs, dose, underlying (cancer) disease, and patient characteristics (e.g., age, genetics, and body constitution). Another factor that hinders the direct use of results from animals is inadequate collaboration between basic science and clinical science in relation to CIM. Here, we briefly describe CIM pathophysiology, particularly the basic knowledge that has been obtained from CIM animal models. These model studies have indicated potential new preventive and ameliorating interventions, including supplementation with natural bioactive diets (e.g., milk fractions, colostrum, and plant extracts), nutrients (e.g., polyunsaturated fatty acids, short-chain fatty acids, and glutamine), and growth factor peptides (e.g., transforming growth factor and glucagon-like peptide-2), as well as manipulations of the gut microbiota (e.g., prebiotics, probiotics, and antibiotics). Rodent CIM models allow well-controlled, in-depth studies of animals with or without tumors while pig models more easily make clinically relevant treatment regimens possible. In synergy, animal models of CIM provide the basic physiological understanding and the new ideas for treatment that are required to make competent decisions in clinical practice.

Human small intestine is capable of restoring barrier function after short ischemic periods

AIM

To assess intestinal barrier function during human intestinal ischemia and reperfusion (IR).

METHODS

In a human experimental model, 6 cm of jejunum was selectively exposed to 30 min of ischemia (I) followed by 30 and 120 min of reperfusion (R). A sham procedure was also performed. Blood and tissue was sampled at all-time points. Functional barrier function was assessed using dual-sugar absorption tests with lactulose (L) and rhamnose (R). Plasma concentrations of citrulline, an amino acid described as marker for enterocyte function were measured as marker of metabolic enterocytes restoration. Damage to the epithelial lining was assessed by immunohistochemistry for tight junctions (TJs), by plasma marker for enterocytes damage (I-FABP) and analyzed by electron microscopy (EM) using lanthanum nitrate as an electrondense marker.

RESULTS

Plasma L/R ratio’s were significantly increased after 30 min of ischemia (30I) followed by 30 min of reperfusion (30R) compared to control (0.75 ± 0.10 vs 0.20 ± 0.09, P < 0.05). At 120 min of reperfusion (120R), ratio’s normalized (0.17 ± 0.06) and were not significantly different from control. Plasma levels of I-FABP correlated with plasma L/R ratios measured at the same time points (correlation: 0.467, P < 0.01). TJs staining shows distortion of staining at 30I. An intact lining of TJs was again observed at 30I120R. Electron microscopy analysis revealed disrupted TJs after 30I with paracellular leakage of lanthanum nitrate, which restored after 30I120R. Furthermore, citrulline concentrations closely paralleled the histological perturbations during intestinal IR.

CONCLUSION

This study directly correlates histological data with intestinal permeability tests, revealing that the human gut has the ability of to withstand short episodes of ischemia, with morphological and functional recovery of the intestinal barrier within 120 min of reperfusion.

US oncology-wide incidence, duration, costs and deaths from chemoradiation mucositis and antimucositis therapy benefits

Approximate oncology-wide incidence, duration, costs and deaths associated with mucositis and identify health economic benefits of antimucositis therapies. Review the literature relevant to the clinical experience of mucositis by pathophysiology, incidence, duration, costs and deaths. Use US insurance actuarial and epidemiology on cancer to generalize an oncology-wide impact of toxic mucositis. Toxic mucositis causes oropharyngoesophageal ulcerations, chemo-induced nausea, vomiting and diarrhea. Acutely, it lasts 102 days/six cycles of chemotherapy, 60 days in human stem-cell transplantation patients and 70-84 days in head and neck cancer patients at annual costs of US$13.23 billion/522,166 treated patients (US$20,892/erosive-type mucositis patient, US$25,337/physiologic mucositis patient) and 46,699 deaths. Using antimucositis therapies prior to 2013 provided fractional benefits at high costs. By completely preventing and rapidly reversing mucositis, high-potency polymerized cross-linked sucralfate promises superior health economic benefits.

Tumor Necrosis Factor-Alpha Inhibitor Etanercept Does Not Alter Methotrexate-Induced Gastrointestinal Mucositis in Rats

OBJECTIVES

Gastrointestinal (GI) mucositis is a severe adverse effect of chemotherapy and radiotherapy. Proinflammatory cytokines are thought to play an important role in the pathophysiology of GI mucositis. We aimed to determine the effect of the tumor necrosis factor-alpha (TNF-α) inhibitor etanercept on the severity of mucositis in a previously established methotrexate (MTX)-induced GI mucositis rat model.

METHODS

Male Wistar rats received 60 mg/kg MTX on day 0 intravenously. Rats were treated daily with either etanercept (TNF-α inhibitor) 5 mg/kg or NaCl 0.9% subcutaneously from day -3 till day 3. Control rats received NaCl 0.9% intravenously and etanercept subcutaneously. The severity of mucositis was determined by intake, bodyweight, plasma citrulline, and by a function test (absorption of an oral glucose bolus). On day 4 and day 10 rats were terminated. Villus length, crypt length, intestinal myeloperoxidase, and plasma etanercept levels were determined.

RESULTS

The administration of MTX induced mucositis in all rats. Etanercept did not cause a change in the degree of mucositis. Bodyweight, intake, and glucose levels were not altered by etanercept; villus length was comparable; and there was no difference in myeloperoxidase and citrulline level. Etanercept levels in plasma were significantly increased in the etanercept rats (P < 0.05).

CONCLUSIONS

TNF-α inhibitor etanercept did not alter the severity of mucositis in the rat, suggesting that targeting only the inflammatory pathway of TNF-α is not effective for decreasing the severity of GI mucositis induced by high-dose MTX. Etanercept alone is not useful for the treatment of MTX-induced GI mucositis.

Surface-enhanced Raman spectroscopy competitive binding biosensor development utilizing surface modification of silver nanocubes and a citrulline aptamer

A point-of-care (PoC) device with the ability to detect biomarkers at low concentrations in bodily fluids would have an enormous potential for medical diagnostics outside the central laboratory. One method to monitor analytes at low concentrations is by using surface-enhanced Raman spectroscopy (SERS). In this preliminary study toward using SERS for PoC biosensing, the surface of colloidal silver (Ag) nanocubes has been modified to test the feasibility of a competitive binding SERS assay utilizing aptamers against citrulline. Specifically, Ag nanocubes were functionalized with mercaptobenzoic acid, as well as a heterobifunctional polyethylene glycol linker that forms an amide bond with the amino acid citrulline. After the functionalization, the nanocubes were characterized by zeta-potential, transmission electron microscopy images, ultraviolet/visible spectroscopy, and by SERS. The citrulline aptamers were developed and tested using backscattering interferometry. The data show that our surface modification method does work and that the functionalized nanoparticles can be detected using SERS down to a 24.5 picomolar level. Last, we used microscale thermophoresis to show that the aptamers bind to citrulline with at least a 50 times stronger affinity than other amino acids. Download PDF SAVE FOR LATER

Biomarkers and non-invasive tests for gastrointestinal mucositis

Gastrointestinal mucositis is a complex inflammatory reaction of the mucous membranes, a side effect of both chemotherapy and radiotherapy. Currently, assessment scales are used to diagnose mucositis. However, a biomarker which would determine whether there is mucositis and thereby establish the severity objectively would be very useful. This will give the opportunity to evaluate studies, to determine risk factors and incidence, and it will make it possible to compare studies. Moreover, this biomarker might improve clinical management for patients. In this paper, we reviewed studies concerning potential biomarkers in blood samples and fecal samples, and potential tests in breath samples and urine samples. We include biomarkers and tests studied in animal models and/or in clinical trials, and discuss the validity, diagnostic accuracy, and applicability.

Feeding strategies in pediatric cancer patients with gastrointestinal mucositis: a multicenter prospective observational study and international survey

INTRODUCTION

Currently, there is no adequate prevention or treatment for both oral and gastrointestinal mucositis induced by chemotherapy and/or radiotherapy. Supportive care of symptoms plays a primary role during mucositis in the pediatric clinical setting. We aimed to get insight in the currently used feeding strategies in clinical practice in pediatric cancer patients with chemotherapy-induced mucositis.

METHODS

A prospective observational study was performed to identify feeding strategies after chemotherapy courses causing mucositis in almost all patients at the University Medical Center Groningen (UMCG), the Academic Medical Center Amsterdam (AMC), and the Princess Maxima Center Utrecht (PMC). Consecutive patients, aged 0-18 years, either diagnosed with B cell non-Hodgkin lymphoma (B-NHL) or scheduled for autologous stem cell transplantation (SCT) between April 2015 and September 2016 were included in this study. In addition to the observational study in the Netherlands, an international online questionnaire was conducted for pediatric oncology centers.

RESULTS

A total of 13 patients were included, after 21 chemotherapy courses. No nutritional support was administered after 23.8% courses, tube feeding after 19.0% of the courses, TPN in 19.0% of courses, and 38.1% received a combination of tube feeding and TPN. The international survey revealed that 63.2% of the centers administered tube feeding as first choice, 31.6% administered only TPN as first choice, and one center administered a combination as first choice.

CONCLUSIONS

There is a variability in feeding strategies in the clinical practice both in the Netherlands as well as worldwide. This study is a basis for future studies in this important clinical field to develop clinical trials comparing tube feeding and TPN both in adult and pediatric patients.

Effect of Oral Insulin on the Severity and Recovery of Methotrexate-Induced Gastrointestinal Mucositis in the Rat

OBJECTIVES

Gastrointestinal (GI) mucositis is an adverse-effect of chemo- and radiotherapy. Oral insulin has been suggested as possible intestinal growth factor and possible intervention for GI mucositis. We aimed to determine the effect of oral insulin on the severity and recovery of mucositis in a methotrexate (MTX)-induced GI mucositis rat model.

METHODS

Male Wistar rats (n = 24) received a single injection of 60 mg/kg MTX intravenously at day 0. From day -3 oral insulin was added to the drinking water. Group MTX received normal drinking water, group MTX+INS0.5 received 0.5 U/mL insulin, and group MTX+INS1 received 1 U/mL insulin in drinking water. The severity of mucositis was determined by intake, bodyweight, illness, and plasma citrulline. In the recovery phase, the function of the gut was tested with an oral glucose tolerance test, and villus and crypt length of the small intestine were measured.

RESULTS

MTX-induced mucositis in all 3 groups and oral insulin did not cause a change in the severity of mucositis, with comparable bodyweight, food intake, and water intake. Oral insulin did not alter the enterocyte mass, determined with plasma citrulline. The glucose level after bolus was higher in the MTX group than the MTX+INS1 group (P < 0.05). Histology was not significant different between all groups.

CONCLUSIONS

Oral insulin does not alter the severity or the acceleration of recovery of mucositis. Therefore, we conclude that it is not useful to further study oral insulin as possible intervention to prevent or treat chemotherapy-induced GI mucositis.

Leigh-Like Syndrome Due to Homoplasmic m.8993T>G Variant with Hypocitrullinemia and Unusual Biochemical Features Suggestive of Multiple Carboxylase Deficiency (MCD)

Leigh syndrome (LS), or subacute necrotizing encephalomyelopathy, is a genetically heterogeneous, relentlessly progressive, devastating neurodegenerative disorder that usually presents in infancy or early childhood. A diagnosis of Leigh-like syndrome may be considered in individuals who do not fulfil the stringent diagnostic criteria but have features resembling Leigh syndrome.We describe a unique presentation of Leigh-like syndrome in a 3-year-old boy with elevated 3-hydroxyisovalerylcarnitine (C5-OH) on newborn screening (NBS). Subsequent persistent plasma elevations of C5-OH and propionylcarnitine (C3) as well as fluctuating urinary markers were suggestive of multiple carboxylase deficiency (MCD). Normal enzymology and mutational analysis of genes encoding holocarboxylase synthetase (HLCS) and biotinidase (BTD) excluded MCD. Biotin uptake studies were normal excluding biotin transporter deficiency. His clinical features at 13 months of age comprised psychomotor delay, central hypotonia, myopathy, failure to thrive, hypocitrullinemia, recurrent episodes of decompensation with metabolic keto-lactic acidosis and an episode of hyperammonemia. Biotin treatment from 13 months of age was associated with increased patient activity, alertness, and attainment of new developmental milestones, despite lack of biochemical improvements. Whole exome sequencing (WES) analysis failed to identify any other variants which could likely contribute to the observed phenotype, apart from the homoplasmic (100%) m.8993T>G variant initially detected by mitochondrial DNA (mtDNA) sequencing.Hypocitrullinemia has been reported in patients with the m.8993T>G variant and other mitochondrial disorders. However, persistent plasma elevations of C3 and C5-OH have previously only been reported in one other patient with this homoplasmic mutation. We suggest considering the m.8993T>G variant early in the diagnostic evaluation of MCD-like biochemical disturbances, particularly when associated with hypocitrullinemia on NBS and subsequent confirmatory tests. An oral biotin trial is also warranted.

Posaconazole plasma exposure correlated to intestinal mucositis in allogeneic stem cell transplant patients

PURPOSE

Low posaconazole plasma concentrations (PPCs) are frequently encountered in allogeneic hematopoietic stem cell transplant (HSCT) patients, due to variable gastrointestinal absorption. In this study, the impact of intestinal mucositis on posaconazole exposure is investigated.

PATIENTS AND METHODS

A prospective pharmacokinetic study was performed including allogeneic HSCT patients receiving posaconazole prophylaxis with the oral suspension or tablets. Steady state PPCs were determined using high-performance liquid chromatography-fluorescence detection at the day of transplantation (=day 0), day +7, and +14. Citrulline was measured using liquid chromatography-tandem mass spectrometry to evaluate severity of mucositis, at baseline (day -7 or -6), and at day 0, +7 and +14. Additionally, citrulline plasma concentrations and steady state trough PPCs were determined in hematological patients without HSCT or mucositis.

RESULTS

Thirty-four HSCT patients received posaconazole oral suspension together with 25 cL of Coca Cola, 6 HSCT patients received posaconazole tablets and 33 hematological patients not receiving HSCT received posaconazole oral suspension. The median (interquartile range) average PPC was 0.26 mg/L (0.17-0.43), 0.67 mg/L (0.27-1.38), and 1.08 mg/L (0.96-1.38), with suspension in HSCT patients, suspension in hematological patients and tablets in HSCT patients, respectively. A higher trough PPC was encountered with the oral suspension when citrulline plasma concentrations were above 10 μmol/L compared to values below 10 μmol/L (p < 0.001), whereas for tablets, average PPCs remained high with citrulline plasma concentrations below or above 10 μmol/L (p = 0.64).

CONCLUSION

Posaconazole tablets should be preferred to suspension in HSCT patients immediately after transplantation to prevent insufficient plasma exposure due to intestinal mucositis.

Pharmacokinetics of Posaconazole Oral Suspension in Children Dosed According to Body Surface Area

BACKGROUND

Antifungal prophylaxis remains challenging in immunocompromised children as no clear consensus has yet been reached about which drug to be used. Posaconazole has a broad spectrum of activity, a favorable safety profile and excellent prophylactic activity in adults. However, a lack of pharmacokinetic studies in pediatric patients hampers routine implementation. This study investigates the pharmacokinetics of a newly introduced posaconazole dosing regimen based on the body surface area in pediatric hematologic patients.

METHODS

In this prospective pharmacokinetic study, 8 blood samples were taken during 1 dosing interval at steady state in children aged 13 years or younger with hematologic malignancy, who were treated prophylactically with posaconazole oral suspension at a dose of 120 mg/m 3 times daily. Posaconazole plasma concentrations were determined using high-performance liquid chromatography fluorescence detection.

RESULTS

One hundred twelve samples were taken from 14 patients with a mean age of 6.7 ± 2.8 years. A median posaconazole daily dose of 100.0 mg (77.3-100.0) 3 times daily (tid), corresponding to a median of 117.9 mg/m (112.2-120.4) tid, resulted in mean trough posaconazole plasma concentrations of 0.85 ± 0.56 mg/L. Pharmacokinetic analysis revealed a clearance of 0.8 L/(h kg) (0.5-1.4). No invasive fungal infections or adverse events were encountered during treatment.

CONCLUSIONS

Posaconazole is a promising antifungal agent to be used prophylactically in hematologic patients aged 13 years or younger. Administering posaconazole oral suspension in a dosage of 120 mg/m tid results in adequate posaconazole plasma exposure, without significant adverse events.

Propolis aqueous extract preserves functional integrity of murine intestinal mucosa after exposure to ionizing radiation

The ability of a specially prepared water propolis extract (PWE) to preserve the functional activity of the intestinal mucosa after radiation exposure was studied. PWE was given orally (650 mg/kg) to rats five days prior to irradiation by 6 Gy and continued for further two days. Rats were sacrificed 24h later, intestinal segments were examined histologically and homogenates were used to assess relevant biochemical parameters reflecting intestinal injury. Irradiation led to a rise in the histological damage score, a rise in tissue TNF-α and TBARS, and a decrease in sucrase, alkaline phosphatase, GSH and cholecystokinin as well as a decrease in plasma citrulline. The findings reflect a decrease in intestinal functional activity. PWE preserved the intestinal integrity and largely protected against the changes induced in the histology damage score and all parameters measured, possibly as a result of the antioxidant and anti-inflammatory action of its caffeic acid content.

Effect of minimal enteral feeding on recovery in a methotrexate-induced gastrointestinal mucositis rat model

PURPOSE

Patients suffering from gastrointestinal mucositis often receive parenteral nutrition as nutritional support. However, the absence of enteral nutrition might not be beneficial for the intestine. We aimed to determine the feasibility of minimal enteral feeding (MEF) administration in a methotrexate (MTX)-induced mucositis rat model and thereby determine the effect of MEF on recovery.

METHODS

Male Wistar rats were attached to swivel systems from day 1 to 5 after 45 mg/kg MTX IV injection. The MTX group continued ad libitum feeding, and the MTX + MEF group continued ad libitum feeding and received from day 1 to 5 continuously MEF. MEF consisted of 20% of their normal caloric intake. We measured body weight, intake, and plasma citrulline. At day 10, the rats were terminated and villus and crypt length were measured.

RESULTS

The administration of MEF caused no increased severity of mucositis phenotype, with comparable caloric intake, body weight, and plasma citrulline during mucositis. The recovery of plasma citrulline levels was not different between both groups. At day 7 and 8, the MTX + MEF group gained significantly more weight (p < 0.05 and p < 0.01, respectively), and at day 8 and 9 the total caloric intake was significantly increased (p < 0.01 and p < 0.05, respectively) compared to the MTX group. At day 10, the rats from the MTX + MEF group showed a significant increase in jejunal villus length compared to the MTX group (p < 0.05).

CONCLUSIONS

This is the first study in which the feasibility of MEF administration during chemotherapy-induced mucositis was determined. This study indicates that MEF administration is feasible during mucositis and suggests that MEF accelerates recovery after MTX-induced mucositis.

Chemotherapy-driven dysbiosis in the intestinal microbiome

BACKGROUND

Chemotherapy is commonly used as myeloablative conditioning treatment to prepare patients for haematopoietic stem cell transplantation (HSCT). Chemotherapy leads to several side effects, with gastrointestinal (GI) mucositis being one of the most frequent. Current models of GI mucositis pathophysiology are generally silent on the role of the intestinal microbiome.

AIM

To identify functional mechanisms by which the intestinal microbiome may play a key role in the pathophysiology of GI mucositis, we applied high-throughput DNA-sequencing analysis to identify microbes and microbial functions that are modulated following chemotherapy.

METHODS

We amplified and sequenced 16S rRNA genes from faecal samples before and after chemotherapy in 28 patients with non-Hodgkin's lymphoma who received the same myeloablative conditioning regimen and no other concomitant therapy such as antibiotics.

RESULTS

We found that faecal samples collected after chemotherapy exhibited significant decreases in abundances of Firmicutes (P = 0.0002) and Actinobacteria (P = 0.002) and significant increases in abundances of Proteobacteria (P = 0.0002) compared to samples collected before chemotherapy. Following chemotherapy, patients had reduced capacity for nucleotide metabolism (P = 0.0001), energy metabolism (P = 0.001), metabolism of cofactors and vitamins (P = 0.006), and increased capacity for glycan metabolism (P = 0.0002), signal transduction (P = 0.0002) and xenobiotics biodegradation (P = 0.002).

CONCLUSIONS

Our study identifies a severe compositional and functional imbalance in the gut microbial community associated with chemotherapy-induced GI mucositis. The functional pathways implicated in our analysis suggest potential directions for the development of intestinal microbiome-targeted interventions in cancer patients.

Pretreatment With L-Citrulline Positively Affects the Mucosal Architecture and Permeability of the Small Intestine in a Murine Mucositis Model

BACKGROUND

Mucositis is a common complication in patients undergoing radiotherapy and chemotherapy. It is associated with pain, poor quality of life, and malnutrition, leading to an increased number of hospital admissions and prolonged hospitalization. The use of immunonutrients may be an alternative treatment option, which may help to improve patient outcome.

OBJECTIVE

Here we assessed the impact of L-citrulline (CIT) on a murine model of 5-fluorouracil (5FU)-induced mucositis.

METHODS

Swiss male mice were randomized into 4 groups: control, CIT, 5FU, and 5FU+CIT. Mice were fed with commercial chow and supplemented with an oral solution of alanine (control and 5FU groups) or CIT (CIT and 5FU+CIT groups). On the seventh day, mice received intraperitoneal phosphate-buffered saline or 5FU (200 mg/kg, single dose) to induce mucositis. On the 10th day, mice were euthanized, and the blood and small intestines were harvested. Body weight, morphology, histopathology score (hematoxylin and eosin) of the small intestine (from 0-12), myeloperoxidase activity, oxidative stress level, and intestinal permeability were assessed.

RESULTS

We observed significant weight loss after the administration of 5FU in both treated and control animals. CIT administration contributed to a partial recovery of the mucosal architecture as well as an intermediate reduction of the histopathologic score, and functional intestinal permeability was partially rescued.

CONCLUSIONS

CIT administration attenuated 5FU-mediated damage to the mucosal architecture of the small intestine, decreasing the size of the injured areas and promoting decreased intestinal permeability.

Risk analysis, diagnosis and management of gastrointestinal mucositis in pediatric cancer patients

Mucositis is a complex inflammatory reaction of the mucous membranes of the alimentary tract upon chemotherapy and radiotherapy treatment in oncology patients. Mucositis can be subdivided in oral and gastrointestinal mucositis (GI mucositis). The damage to the gastrointestinal tract compromises the intestinal function and thereby the nutritional status and the quality of life, and eventually affects survival. The literature on GI mucositis focuses mainly on adults. This review focuses on data available on GI mucositis in pediatric cancer patients. An evaluation of the clinical presentation and consequences of GI mucositis in children is outlined. The review summarizes key issues for clinicians with respect to risk analysis for developing mucositis and the diagnosis of this condition in children. Information on these issues is obtained from clinical trials in children and adults, and from animal models. Diagnostic tools and assessment of severity of GI mucositis in children is elaborated on. Furthermore, the clinical management of the symptoms and consequences of GI mucositis in children, with specific focus on nutritional support, are discussed.

Accelerated hematopoietic syndrome after radiation doses bridging hematopoietic (H-ARS) and gastrointestinal (GI-ARS) acute radiation syndrome: early hematological changes and systemic inflammatory response syndrome in minipig

PURPOSE

To characterize acute radiation syndrome (ARS) sequelae at doses intermediate between the bone marrow (H-ARS) and full gastrointestinal (GI-ARS) syndrome.

METHODS

Male minipigs, approximately 5 months old, 9-12 kg in weight, were irradiated with Cobalt-60 (total body, bilateral gamma irradiation, 0.6 Gy/min). Endpoints were 10-day survival, gastrointestinal histology, plasma citrulline, bacterial translocation, vomiting, diarrhea, vital signs, systemic inflammatory response syndrome (SIRS), febrile neutropenia (FN).

RESULTS

We exposed animals to doses (2.2-5.0 Gy) above those causing H-ARS (1.6-2.0 Gy), and evaluated development of ARS. Compared to what was observed during H-ARS (historical data: Moroni et al. 2011a , 2011c ), doses above 2 Gy produced signs of increasingly severe pulmonary damage, faster deterioration of clinical conditions, and faster increases in levels of C-reactive protein (CRP). In the range of 4.6-5.0 Gy, animals died by day 9-10; signs of the classic GI syndrome, as measured by diarrhea, vomiting and bacterial translocation, did not occur. At doses above 2 Gy we observed transient reduction in circulating citrulline levels, and animals exhibited earlier depletion of blood elements and faster onset of SIRS and FN.

CONCLUSIONS

An accelerated hematopoietic subsyndrome (AH-ARS) is observed at radiation doses between those producing H-ARS and GI-ARS. It is characterized by early onset of SIRS and FN, and greater lung damage, compared to H-ARS.

Relative defects in mucosal immunity predict acute graft-versus-host disease

Impairment of gut mucosal immunity by the transplant process could facilitate translocation of commensal bacteria and thereby augment the graft-versus-host response. To begin to assess the influence of gut mucosal immunity on the development of acute graft-versus-host disease (GVHD), we conducted a prospective study in 24 pediatric allogeneic hematopoietic cell transplant recipients, assessing 4 fecal markers of mucosal immunity: calprotectin, soluble CD8 (sCD8), soluble intracellular adhesion molecule 1, and β-defensin-2. Stool samples were collected prospectively on transplant days 0, +5, +10, and +15 and analyzed by ELISA. Lower levels on day +5 (calprotectin and β-defensin-2) and day +10 (calprotectin, β-defensin-2, and sCD8) were associated with subsequent acute GVHD. The most striking difference was with calprotectin on day +10. Patients with levels below 424 mg/kg had an incidence of 77.8%, whereas those with levels above this threshold had a cumulative incidence of 0% (P = .002). Relative defects in gut mucosal immunity may be important in the pathogenesis of acute GVHD.

Mucositis not neutropenia determines bacteremia among hematopoietic stem cell transplant recipients

BACKGROUND

In the 1960s, it was reported that infectious complications were the main cause of fever during neutropenia that followed hematopoietic stem cell transplant (HSCT). More recently, mucositis has become recognized as an important determinant of the inflammatory response and infectious complications.

METHODS

The objective of this prospective study was to determine the impact of intestinal mucositis, as measured by plasma citrulline, and neutropenia on the systemic inflammatory response (C-reactive protein) and the occurrence of bacteremia among 2 cohorts of HSCT recipients: 1 composed of 18 patients who had been treated with a myeloablative (MA) regimen (high-dose melphalan) and the other involving 19 patients who had received the non-myeloablative (NMA) regimen (fludarabine and cyclophosphamide). Blood cultures were obtained for surveillance from admission onwards as well as at the onset of fever.

RESULTS

The MA regimen induced severe intestinal mucositis manifest by citrullinemia <10 μmol/L, which was accompanied by an inflammatory response, and bacteremia affected 8 (44%) of 18 patients and coincided with the nadir of citrullinemia. By contrast, those who had been treated with the NMA regimen did not develop severe intestinal mucositis, had a moderate inflammatory response, and only 2 (11%) of the 19 patients developed bacteremia. However, both groups experienced profound neutropenia and its duration was significantly longer for those receiving the NMA regimen.

CONCLUSION

This study suggests that severe intestinal mucositis, i.e., citrullinemia <10 μmol/L, defines the period of risk of bacteremia better than does neutropenia, and that measuring plasma citrulline may prove useful in deciding who needs empirical antimicrobial therapy and when.

Host impairments in patients with neoplastic diseases

Healthy individuals possess an immune system comprising physical barriers, innate and acquired immunity as well as the indigenous microflora that populate the body surfaces. The immune system maintains constant vigilance over the body at the cellular level as well as at the interface between the host integument and the resident microflora. However, neoplastic diseases and their treatment often lead to impaired immunity resulting in an increased risk of infections due to viruses, bacteria, fungi, and protozoa. This chapter explores the various aspects of host impairment focusing on the components of immunity and the interplay between them to explain why it is that these patients succumb to infections per se. In so doing, we hope that the reader will be better equipped to understand the risks patients face so as to anticipate potential infectious complications and implement appropriate measures to help attain successful remission of the neoplastic diseases and maintain the best quality of life for the patient.

Biomarkers of small intestinal mucosal damage induced by chemotherapy: an emerging role for the 13C sucrose breath test

Gastrointestinal mucosal toxicity is extremely common following cytotoxic therapies. The alimentary mucosa is particularly susceptible to injury and dysfunction, leading to many debilitating complications. Despite much research, there is currently no single noninvasive biomarker to detect gut injury. Several biomarkers have been investigated in the context of gastrointestinal diseases, which may prove useful in the oncology arena. Identification of a biomarker that is easy to obtain and measure and that accurately identifies mucosal damage would allow for improved patient diagnosis of toxicities and for personalized treatment regimens. In this review, we highlight the effectiveness of urine and breath tests as potential clinically effective biomarkers, with significant focus placed on the emerging role of the carbon-13 sucrose breath test (13C SBT). The 13C SBT provides a simple, noninvasive, and integrated measure of gut function. The 13C SBT also has the potential to monitor gut function in the setting of cytotoxic therapy-induced mucositis, or in the assessment of the efficacy of antimucositis agents.

Serum citrulline levels as a marker of enterocyte function in patients after allogeneic hematopoietic stem cells transplantation - a pilot study

Background

Citrulline is an amino acid produced by enterocytes. Serum citrulline concentration has been proposed as a marker of enterocyte mass and function. Our study focused on evaluation of citrulline levels in patients with diarrhea related to toxic intestinal damage (mucositis), intestinal graft versus host disease (GVHD), and other etiology of diarrhea (e.g., dysmicrobia) after allogeneic stem cells transplantation (SCT).

Material/Methods

This was a prospective study in 11 adults (18 blood samples) with diarrhea developed after allogeneic SCT in 4/2011–1/2012 compared to twenty healthy control samples.

Results

The median (interquartile range) of citrulline levels was significantly lower in the transplanted patients group compared to healthy controls: 9.3 (3.62–15.38) vs. 33.3 (26.82–36.23) μmol/L, p<0.0001. The median values of citrulline in patients with post-transplant toxic intestinal mucositis (n=8, days 1–22 post-transplant) vs. intestinal GVHD (n=7, day 43–142) vs. other etiology of diarrhea (e.g., dysmicrobia) (n=3, day 120–127) were: 9.55 (2.95–12.03) vs. 5 (3.85–9.05) vs. 15.6 (15.45–18.3) μmol/L resp. Serum citrulline levels were significantly higher in other (eg, dysmicrobic) etiology of diarrhea in comparison with mucositis (p=0.0336) and GVHD (p=0.0152).

Conclusions

Citrulline levels are very low shortly after the myeloablative FLU/MEL or BuCY2 conditioning allogeneic SCT due to the toxic intestinal damage. Significantly low levels of citrulline were also in patients with intestinal GVHD later on. Other observations in larger groups of patients are necessary before any specific recommendation for citrulline levels monitoring in intestinal GVHD can be made.