Mechanistic inference of the metabolic rates underlying [Formula: see text]C breath test curves

Carbon stable isotope breath tests offer new opportunities to better understand gastrointestinal function in health and disease. However, it is often not clear how to isolate information about a gastrointestinal or metabolic process of interest from a breath test curve, and it is generally unknown how well summary statistics from empirical curve fitting correlate with underlying biological rates. We developed a framework that can be used to make mechanistic inference about the metabolic rates underlying a 13C breath test curve, and we applied it to a pilot study of 13C-sucrose breath test in 20 healthy adults. Starting from a standard conceptual model of sucrose metabolism, we determined the structural and practical identifiability of the model, using algebra and profile likelihoods, respectively, and we used these results to develop a reduced, identifiable model as a function of a gamma-distributed process; a slower, rate-limiting process; and a scaling term related to the fraction of the substrate that is exhaled as opposed to sequestered or excreted through urine. We demonstrated how the identifiable model parameters impacted curve dynamics and how these parameters correlated with commonly used breath test summary measures. Our work develops a better understanding of how the underlying biological processes impact different aspect of 13C breath test curves, enhancing the clinical and research potential of these 13C breath tests.

Circulating Dipeptidyl Peptidase Activity Is a Potential Biomarker for Inflammatory Bowel Disease

INTRODUCTION

Dipeptidyl peptidase (DPP)-4 is part of a larger family of proteases referred to as DPPs. DPP4 has been suggested as a possible biomarker for inflammatory bowel disease (IBD). Circulating DPP4 (cDPP4) enzyme activity was investigated as a potential biomarker for IBD. In addition, DPP enzyme activity and gene expression were quantified in colonic tissue of patients with IBD and non-IBD.

METHODS

In study 1, DPP enzyme activity was quantified in plasma samples from 220 patients with IBD (Crohn's disease [CD] n = 130 and ulcerative colitis [UC] n = 90) and non-IBD controls (n = 26) using a colorimetric assay. In study 2, tissue and plasma samples were collected from 26 patients with IBD and 20 non-IBD controls. Plasma C-reactive protein (CRP) was quantified in all patients. Colonic DPP4, DPP8, DPP9, and fibroblast activation protein (FAP) gene expression was determined by quantitative polymerase chain reaction. cDPP and cFAP enzyme activity was also measured. Sensitivity and specificity were determined by receiver operating characteristic curve analysis.

RESULTS

In study 1, total cDPP activity was found to differentiate patients with CD with active disease (n = 18) from those in remission (n = 19; sensitivity 78% and specificity 63%). In study 2, total cDPP and cFAP activity was 28% and 48% lower in patients with elevated CRP (>10 mg/L), respectively, compared with patients with normal CRP. Gene expression of DPP4, FAP, and DPP8 was also significantly higher in colonic biopsies from patients with IBD compared with non-IBD patients (P < 0.05).

DISCUSSION

Our findings implicate the DPP enzyme family in intestinal inflammation and suggest future biomarker applications to differentiate the pathophysiological aspects of IBD.

P–688 Assessment of ovarian vascularity by three-dimensional vaginal power Doppler on day two of menstrual cycle to predict the number of mature eggs collected

Study question

Could ovarian vascularity indices, measured by 3-dimensional (3D) vaginal power Doppler, predict the number of mature oocytes collected after controlled ovarian stimulation?

Summary answer

Ovarian vascularity index (VI) may be an indicator of poor (&lt;three mature eggs collected) and high (&gt;ten mature eggs collected) ovarian responses to gonadotropins.

What is known already

Poor and/or hyper ovarian responses to gonadotropins may be related to cycle cancellation during controlled ovarian stimulation (COS). In this context, gonadotropin dose is often individualized using patient features that predict ovarian response (such as age, antral follicular count (AFC) and anti-Müllerian hormone (AMH)). In parallel, ovarian vascularity color doppler is a valuable evaluation method to predict the ovarian hyperstimulation syndrome and the growth/maturity of Graafian follicles. The aim of the present study is to estimate the utility of 3-dimensional vaginal power Doppler and ovarian vascular flow indices in the prediction of the number of mature occytes collected after COS.

Study design, size, duration

A prospective study was conducted on 200 couples undergoing intracytoplasmic sperm injection cycle at Al Hadi Laboratory and Medical center, Beirut, Lebanon. It was performed between January 2020 and July 2020. Couples were categorized into poor responders group (3 or less metaphase II (MII) eggs collected) (n = 43), high responders group (10 or more MII eggs collected) group (n = 66), and normal responders group (more than 3 and less than 10 MII eggs collected) (n = 66).

Participants/materials, setting, methods

On the second day of the menstrual cycle, ovarian volume and vascularity parameters (vascularity index (VI), flow index (FI), and vascularity flow index (VFI)) were measured using the 3D power Doppler and the Virtual Organ Computer-Aided Analysis. On the same day, the antral follicle count was evaluated and a blood sample for AMH testing was collected. Women included in the study have undergone COS using GnRH antagonist protocol.

Main results and the role of chance

Receiver operator characteristics (ROC) curve model was used to predict the number of mature eggs collected. 7 parameters were used to predict poor and high ovarian responses (Age, AMH, AFC, ovarian volume, VI, FI and VFI). Ovarian VI significantly predicted poor ovarian response to gonadotropins (p = 0.033 and area under the curve (AUC)=0.668). Subsequently, the cut off value was 0.0025 with 84% sensitivity and 83.3% specificity. In parallel, ovarian VI significantly predicted high ovarian response to gonadotropins (p = 0.036 and AUC (0.778)) with a cut off value 0.0375 and with 77.8% sensitivity and 78.3% specificity. Furthermore, VFI significantly predicted high ovarian response to gonadotropins (p = 0.045; AUC=0.677).

Limitations, reasons for caution

It will be necessary to perform a prospective analysis on a broad sample size to validate these findings. In addition, it will be interesting to assess the impact of ovarian vascularity on pregnancy outcomes.

Wider implications of the findings: Assessing ovarian vascularity prior to ovarian stimulation can help reduce the rate of cycle cancellation. In addition, more studies are welcomed in the field to unravel the mechanisms behind altered ovarian vascularity and to test the possibility of restoring normal ovarian physiology.

Trial registration number

Not applicable

Improving cost-effectiveness of endoscopic surveillance for Barrett's esophagus by reducing low-value care: a review of economic evaluations

BACKGROUND

Individuals with Barrett's esophagus are believed to be at 30-120× risk of developing esophageal adenocarcinoma (EAC). Early detection and endoscopic treatment of dysplasia/early cancer confers a significant advantage to patients under surveillance; however, most do not progress past the non-dysplastic state of Barrett's esophagus (NDBE), which is potentially an inefficient distribution of health care resources.

OBJECTIVES

This article aimed to review the outcomes of cost-effectiveness studies reducing low-value care in the context of endoscopic surveillance for non-dysplastic Barrett's esophagus (NDBE).

METHODS

A systematic search was conducted by two reviewers in accordance with PRISMA guidelines.

INCLUSION CRITERIA

cost-utility analyses of endoscopic surveillance of NDBE patients with at least one treatment strategy focused on reduction of surveillance. A narrative synthesis of economic evaluations was undertaken, along with an in-depth analysis of input parameters contributing to stated Incremental cost-effectiveness ratios (ICER). Study appraisal was performed using the consolidated health economic evaluation reporting standards (CHEERS) tool.

RESULTS

10 Studies met inclusion criteria. There was significant variation in cost-model structures, input parameters, ICER values, and willingness-to-pay thresholds between studies. All studies except one concluded guideline-specified endoscopic surveillance for NDBE patients was not cost-effective. Studies that explored a modified surveillance by deselection of low-risk NDBE patients found it to be a cost-effective strategy.

CONCLUSION

Guideline specified endoscopic surveillance for NDBE was not found to be cost-effective in the studies examined. A modified endoscopic surveillance strategy removing individuals with the lowest risk for progression from NDBE to adenocarcinoma is likely to be cost-effective but is dependent on risk profile of patients excluded from surveillance.

Dipeptidyl peptidase 4 inhibitors: Applications in innate immunity?

Dipeptidyl peptidase (DPP)-4 inhibitors are a class of orally available, small molecule inhibitors that prolong the insulinotropic activity of the incretin hormone glucagon-like peptide-1 (GLP-1) and are highly effective for the treatment of Type-2 diabetes. DPP4 can also cleave several immunoregulatory peptides including chemokines. Emerging evidence continues to implicate DPP4 inhibitors as immunomodulators, with recent findings suggesting DPP4 inhibitors modify specific aspects of innate immunity. This review summarises recent insights into how DPP4 inhibitors could be implicated in endothelial, neutrophil and monocyte/macrophage mediated immunity. Additionally, this review highlights additional avenues of research with DPP4 inhibitors in the context of the COVID-19 pandemic.

Breath 13CO2-evidence for a noninvasive biomarker to measure added refined sugar uptake

Increased consumption of added sucrose and high-fructose corn syrup in the human diet has been associated with increasing incidence of obesity and metabolic disease. There are currently no reliable, objective biomarkers for added sugar intake that could be used in individuals or population settings. ¹³C is a stable isotope of carbon, and measurement of blood ¹³C content has been proposed as a marker of added sugar consumption. This study aimed to determine if breath ¹³CO₂ could represent an alternative, noninvasive biomarker to monitor added sugar intake. We undertook retrospective analyses of eight preclinical and human ¹³C-breath studies to define baseline breath ¹³CO₂ characteristics. All samples were analyzed using isotope ratio mass spectrometry, and breath ¹³CO₂ was expressed as the delta value, δ expressed as parts per thousand (‰). All data are expressed as mean ± SEM, with statistical significance considered at P < 0.05. Breath δ¹³CO₂ was significantly elevated in a cumulative manner in rats and mice that consumed a diet containing at least 15% sucrose. Mice fed an American rodent chow diet containing 50% sucrose and 15% corn starch had a significantly higher breath δ¹³CO₂ compared with rodents consuming an Australian rodent chow diet. Furthermore, breath δ¹³CO₂ was significantly increased in a dose-dependent manner in humans that ingested a bolus dose of sucrose. These findings suggest application for baseline breath δ¹³CO₂ as a noninvasive biomarker for added sugar consumption, with broad application for longitudinal assessment of population sugar intake and obesity management strategies.NEW & NOTEWORTHY We have found that breath ¹³CO₂ is increased in rats and mice consuming diets high in sucrose. We also found that human breath ¹³CO₂ is increased in humans consuming increasing amounts of sucrose. Our collective findings suggest that breath ¹³CO₂ represents a potential marker of added dietary sugar consumption.

Development of a non-invasive exhaled breath test for the diagnosis of head and neck cancer

BACKGROUND

Improving the ability to identify early-stage head and neck squamous cell carcinoma (HNSCC) can improve treatment outcomes and patient morbidity. We sought to determine the diagnostic accuracy of breath analysis as a non-invasive test for detecting HNSCC.

METHODS

Standardised breath samples were collected from 181 patients suspected of HNSCC prior to any treatment. A selected ion flow-tube mass spectrometer was used to analyse breath for volatile organic compounds. Diagnosis was confirmed by histopathology. A binomial logistic regression model was used to differentiate breath profiles between cancer and control (benign disease) patients based on mass spectrometry derived variables.

RESULTS

In all, 66% of participants had early-stage primary tumours (T1 and T2) and 58% had regional node metastasis. The optimised logistic regression model using three variables had a sensitivity and specificity of 80% and 86%, respectively, with an AUC for ROC curve of 0.821 (95%CI 0.625-1.0) in the testing cohort.

CONCLUSIONS

Breath analysis for non-invasive diagnosis of HNSCC appears to be practical and accurate. Future studies should be conducted in a primary care setting to determine the applicability of breath analysis for early identification of HNSCC.

Optimisation, validation and field applicability of a 13C-sucrose breath test to assess intestinal function in environmental enteropathy among children in resource poor settings: study protocol for a prospective study in Bangladesh, India, Kenya, Jamaica, Peru and Zambia

INTRODUCTION

Environmental enteropathy (EE) is suspected to be a cause of growth faltering in children with sustained exposure to enteric pathogens, typically in resource-limited settings. A major hindrance to EE research is the lack of sensitive, non-invasive biomarkers. Current biomarkers measure intestinal permeability and inflammation, but not the functional capacity of the gut. Australian researchers have demonstrated proof of concept for an EE breath test based on using naturally ¹³C-enriched sucrose, derived from maize, to assay intestinal sucrase activity, a digestive enzyme that is impaired in villus blunting. Here, we describe a coordinated research project to optimise, validate and evaluate the usability of a breath test protocol based on highly enriched ¹³C-sucrose to quantify physiological dysfunction in EE in relevant target populations.

METHODS AND ANALYSIS

We use the ¹³C-sucrose breath test (¹³C-SBT) to evaluate intestinal sucrase activity in two phases. First, an optimisation and validation phase will (1) confirm that a ¹³C-SBT using highly enriched sucrose tracers reports similar information to the naturally enriched ¹³C-SBT; (2) examine the dose-response relationship of the test to an intestinal sucrase inhibitor; (3) validate the ¹³C-SBT in paediatric coeliac disease (4) validate the highly enriched ¹³C-SBT against EE defined by biopsy in adults and (5) validate the ¹³C-SBT against EE defined by the urinary lactulose:rhamnose ratio (LR) among children in Peru. Second, a cross-sectional study will be conducted in six resource-limited countries (Bangladesh, India, Jamaica, Kenya, Peru and Zambia) to test the usability of the optimised ¹³C-SBT to assess EE among 600 children aged 12-15 months old.

ETHICS AND DISSEMINATION

Ethical approval will be obtained from each participating study site. By working as a consortium, the test, if shown to be informative of EE, will demonstrate strong evidence for utility across diverse, low-income and middle-income country paediatric populations.

TRIAL REGISTRATION NUMBER

NCT04109352; Pre-results.

Breath methane to hydrogen ratio as a surrogate marker of intestinal dysbiosis in head and neck cancer

Exhaled breath compounds can non-invasively detect head and neck squamous cell carcinoma (HNSCC). Here we investigated exhaled compounds related to intestinal bacterial carbohydrate fermentation. Fasting breath samples were collected into 3 litre FlexFoil PLUS bags from patients awaiting a biopsy procedure for suspected HNSCC. Samples were analysed using a Syft selected ion flow-tube mass spectrometer and a Quintron BreathTracker. Two tailed non-parametric significance testing was conducted with corrections for multiple imputations. 74 patients were diagnosed (histological) with HNSCC and 61 patients were benign (controls). The methane to hydrogen ratio was significantly different between cancer and non-cancer controls (p = 0.0440). This ratio increased with tumour stage with a significant difference between T1 and T4 tumours (p = 0.0259). Hydrogen levels were significantly higher in controls who were smokers (p = 0.0129), with no smoking dependent methane changes. There were no differences in short chain fatty acids between groups. Exhaled compounds of intestinal carbohydrate fermentation can detect HNSCC patients. These findings suggest a modified carbohydrate fermentation profile in HNSCC patients that is tumour stage and smoking status dependent.

A review of breath analysis techniques in head and neck cancer

Cancers of the head and neck region are a severely disabling group of diseases with no method for early detection. Analysis of exhaled breath volatile organic compounds shows promise as biomarkers for early detection and disease monitoring. This article reviews breath analysis in the setting of head and neck cancer, with a practical focus on breath sampling techniques, detection technologies and valid data analysis methods. Title and abstract keyword searches were conducted on PubMed and Embase databases to identify English language studies without a time-period limitation. The main inclusion criteria were human studies comparing head and neck cancer patients to healthy controls using exhaled breath analysis. Multiple breath collection techniques, three major detection technologies and multiple data analysis methods were identified. However, the variability in techniques and lack of methodological standardization does not allow for adequate study replication or data pooling. Twenty-two volatile organic compounds identified in five studies have been reported to discriminate head and neck cancer patients from healthy controls. Breath analysis for detection of head and neck cancer shows promise as a non-invasive detection tool. However, methodological standardization is paramount for future research study design to provide the potential for translating these techniques into routine clinical use.

Prebiotics Fructo-, Galacto-, and Mannan-Oligosaccharide Do Not Protect against 5-Fluorouracil-Induced Intestinal Mucositis in Rats

BACKGROUND

Prebiotics selectively stimulate the growth of beneficial bacteria within the gastrointestinal tract, and have been investigated in human and animal studies for their capacity to improve intestinal health.

OBJECTIVE

We investigated the prebiotics fructo-oligosaccharide (FOS), galacto-oligosaccharide (GOS), and mannan-oligosaccharide (MOS) for their potential to alleviate intestinal damage in rats.

METHODS

Female Dark Agouti rats (6-8 wk old, 110-150 g) were allocated to 1 of the following treatment groups (n = 8/group): saline/water, saline/FOS, saline/GOS, saline/MOS, 5-fluorouracil (5FU)/water, 5FU/FOS, 5FU/GOS, and 5FU/MOS. Rats were pretreated with either 5% GOS, MOS, or FOS or vehicle (water) from day -12 to day 0. On day 0, rats received a single intraperitoneal injection of saline or 5FU. Metabolic data were recorded daily and all rats were killed on day 3. Histopathology was quantified in hematoxylin and eosin-stained sections. Intestinal sucrase and myeloperoxidase activity were quantified by biochemical assay. Fecal SCFAs-acetic, propionic, and butyric acid-were also measured. Statistical analysis was by repeated-measures, 2-factor ANOVA or Kruskal-Wallis and Mann-Whitney U test; P < 0.05 was considered statistically significant.

RESULTS

Body weight was significantly decreased in all treatment groups after 5FU injection, with no change in body weight observed in any prebiotic treatment group. Total food intake was lower by ≥7% in the GOS treatment group pre-5FU than in all other groups (P < 0.05). Ileal villus height was 18% higher in GOS-treated rats pre-5FU than in respective water controls (P < 0.05). Jejunal and ileal villus height and crypt depth were significantly decreased in all treatment groups after 5FU injection, with no prebiotic effect observed. SCFAs were differentially increased in prebiotic treatment groups compared with water-only controls (P < 0.05).

CONCLUSIONS

FOS, GOS, and MOS have differential effects in modifying small intestinal pathology and SCFA profiles in rats with healthy and damaged small intestinal mucosa.

The Use of Selected Ion Flow Tube-Mass Spectrometry Technology to Identify Breath Volatile Organic Compounds for the Detection of Head and Neck Squamous Cell Carcinoma: A Pilot Study

Background: Head and neck squamous cell carcinoma (HNSCC) is the sixth most common form of cancer worldwide, with approximately 630,000 new cases diagnosed each year. The development of low-cost and non-invasive tools for the detection of HNSCC using volatile organic compounds (VOCs) in the breath could potentially improve patient care. The aim of this study was to investigate the feasibility of selected ion flow tube mass spectrometry (SIFT-MS) technology to identify breath VOCs for the detection of HNSCC. Materials and Methods: Breath samples were obtained from HNSCC patients (N = 23) and healthy volunteers (N = 21). Exhaled alveolar breath samples were collected into FlexFoil^® PLUS (SKC Limited, Dorset, UK) sampling bags from newly diagnosed, histologically confirmed, untreated patients with HNSCC and from non-cancer participants. Breath samples were analyzed by Selected Ion Flow Tube-Mass Spectrometry (SIFT-MS) (Syft Technologies, Christchurch, New Zealand) using Selective Ion Mode (SIM) scans that probed for 91 specific VOCs that had been previously reported as breath biomarkers of HNSCC and other malignancies. Results: Of the 91 compounds analyzed, the median concentration of hydrogen cyanide (HCN) was significantly higher in the HNSCC group (2.5 ppb, 1.6–4.4) compared to the non-cancer group (1.1 ppb, 0.9–1.3; Benjamini–Hochberg adjusted p < 0.05). A receiver operating curve (ROC) analysis showed an area under the curve (AUC) of 0.801 (95% CI, 0.65952–0.94296), suggesting moderate accuracy of HCN in distinguishing HNSCC from non-cancer individuals. There were no statistically significant differences in the concentrations of the other compounds of interest that were analyzed. Conclusions: This pilot study demonstrated the feasibility of SIFT-MS technology to identify VOCs for the detection of HNSCC.

Development of a 13C Stable Isotope Assay for Dipeptidyl Peptidase-4 Enzyme Activity A New Breath Test for Dipeptidyl Peptidase Activity

Dipeptidyl peptidase-4 inhibitors (DPP4i) are a class of orally available, small molecule inhibitors for the management of Type-II diabetes. A rapid, real-time, functional breath test for DPP4 enzyme activity could help to define DPP4i efficacy in patients that are refractory to treatment. We aimed to develop a selective, non-invasive, stable-isotope ¹³C-breath test for DPP4. In vitro experiments were performed using high (Caco-2) and low (HeLa) DPP4 expressing cells. DPP gene expression was determined in cell lines by qRT-PCR. A DPP4 selective ¹³C-tripeptide was added to cells in the presence and absence of the DPP4 inhibitor Sitagliptin. Gas samples were collected from the cell headspace and ¹³CO₂ content quantified by isotope ratio mass spectrometry (IRMS). DPP4 was highly expressed in Caco-2 cells compared to HeLa cells and using the ¹³C-tripeptide, we detected a high ¹³CO₂ signal from Caco2 cells. Addition of Sitaglitpin to Caco2 cells significantly inhibited this ¹³CO₂ signal. ¹³C-assay DPP4 activity correlated positively with the enzyme activity detected using a colorimetric substrate. We have developed a selective, non-invasive, ¹³C-assay for DPP4 that could have broad translational applications in diabetes and gastrointestinal disease.

Potential disease biomarkers: dipeptidyl peptidase 4 and fibroblast activation protein

The importance of the dipeptidyl peptidase 4 (DPP4) gene family in regulating critical biochemical pathways continues to emerge. The two most well-studied members of the family, DPP4 and fibroblast activation protein (FAP), have been investigated both as therapeutic targets for disease and as diagnostic biomarkers. The interest in DPP4 and FAP as potential disease biomarkers has been driven primarily by observations of altered expression profiles in inflammatory diseases and cancer. Furthermore, the stability and persistence of soluble DPP4 and FAP in the serum make them attractive candidate serology markers. This review summarises investigations into DPP4 and FAP as biomarkers of autoimmune disease, gut inflammation, psychosomatic disorders and malignancy and discusses their potential likelihood as clinically useful tools.

From blood to breath: New horizons for esophageal cancer biomarkers

Esophageal cancer is a lethal cancer encompassing adenocarcinoma and squamous cell carcinoma sub-types. The global incidence of esophageal cancer is increasing world-wide, associated with the increased prevalence of associated risk factors. The asymptomatic nature of disease often leads to late diagnosis and five-year survival rates of less than 15%. Current diagnostic tools are restricted to invasive and costly endoscopy and biopsy for histopathology. Minimally and non-invasive biomarkers of esophageal cancer are needed to facilitate earlier detection and better clinical management of patients. This paper summarises recent insights into the development and clinical validation of esophageal cancer biomarkers, focussing on circulating markers in the blood, and the emerging area of breath and odorant biomarkers.

In vitro development and validation of a non-invasive (13)C-stable isotope assay for ornithine decarboxylase

Oesophageal cancer is a significant cause of cancer related mortality, with increasing incidence worldwide. Ornithine decarboxylase (ODC) is an enzyme involved in polyamine synthesis and cellular proliferation, and ODC expression and activity has been implicated as a prognostic marker of oesophageal cancer. This study aimed to develop and optimise an in vitro (13)C-stable isotope assay for ODC activity as a non-invasive marker of oesophageal cancer. Experiments were performed in triplicate (n  =  3/group/cell line) using Caco2, HeLa, Flo-1, OE33, TE7 and OE21 cell lines (colorectal, cervical, oesophageal adenocarcinoma and oesophageal squamous carcinoma respectively). Following addition of 2mM (13)C-ornithine to cells, 10 ml gas samples were collected from the headspace every 20 min for a total of five hours. Gas samples were analysed using isotope ratio mass spectrometry to quantify (13)CO2. Assay specificity was determined using the selective ODC inhibitor, N-(4'-Pyridoxil)-Ornithine(BOC)-OMe (POB). All data is expressed as δ (13)CO2 from baseline. High ODC activity was detected by (13)C-ornithine assay in Caco2 (32.00  ±  1.12 δ (13)CO2) in contrast to HeLa cells (5.44  ±  0.14 δ (13)CO2) cells. POB inhibited activity in Caco2 cells to 12.87  ±  1.10 δ (13)CO2. Differential ODC activity was detected in all oesophageal cancer cells, and 53 h incubation of cell lines with POB reduced activity by 72%, 56%, 64% and 69% in the Flo-1, OE33, OE21 and TE7 cell lines respectively. We have shown that ODC activity can be selectively detected by a non-invasive, stable-isotope (13)C-ornithine assay. ODC activity was detected in all oesophageal cancer cell lines in vitro. Further studies are indicated to quantify ODC activity in oesophageal cancer patients.

Effects of Streptococcus thermophilus TH-4 in a rat model of doxorubicin-induced mucositis

BACKGROUND

Mucositis is a debilitating intestinal side effect of chemotherapeutic regimens. Probiotics have been considered a possible preventative treatment for mucositis. Streptococcus thermophilus TH-4 (TH-4), a newly identified probiotic, has been shown to partially alleviate mucositis induced by administration of the antimetabolite chemotherapy drug, methotrexate in rats; likely mediated through a mechanism of folate production. However, its effects against other classes of chemotherapy drug have yet to be determined.

AIMS

The authors investigated the effects of TH-4 in a rat model of mucositis induced by the anthracycline chemotherapy drug, doxorubicin.

METHODS

Gastrointestinal damage was induced in female Dark Agouti rats (148.3 ± 1.5 g) by intraperitoneal injection of doxorubicin (20 mg/kg). Animals recieved a daily oral gavage of TH-4 at 10(9) cfu/ml or skim milk (vehicle) from days 0 to 8. At day 6, rats were injected with either saline or doxorubicin. At kill, small intestinal tissues were collected for determination of sucrase and myeloperoxidase (MPO) activities and histological assessment.

RESULTS

Body weight was significantly decreased by doxorubicin compared with normal controls (p < 0.05). Histological parameters, such as crypt depth and villus height, were also significantly decreased by doxorubicin. TH-4 partially prevented the loss of body weight induced by doxorubicin (2.3% compared with 4%), but provided no further therapeutic benefit.

CONCLUSIONS

The minimal amelioration of doxorubicin-induced mucositis by TH-4 further supports folate production as a likely mechanism of TH-4 action against methotrexate-induced mucositis. Further studies into TH-4 are required to confirm its applicability to other conventional chemotherapy regimens.

Emerging evidence on the pathobiology of mucositis

BACKGROUND

Considerable progress has been made in our understanding of the biological basis for cancer therapy-induced mucosal barrier injury (mucositis). The last formal review of the subject by MASCC/ISOO was published in 2007; consequently, an update is timely.

METHODS

Panel members reviewed the biomedical literature on mucositis pathobiology published between January 2005 and December 2011.

RESULTS

Recent research has provided data on the contribution of tissue structure changes, inflammation and microbiome changes to the development of mucositis. Additional research has focused on targeted therapy-induced toxicity, toxicity clustering and the investigation of genetic polymorphisms in toxicity prediction. This review paper summarizes the recent evidence on these aspects of mucositis pathobiology.

CONCLUSION

The ultimate goal of mucositis researchers is to identify the most appropriate targets for therapeutic interventions and to be able to predict toxicity risk and personalize interventions to genetically suitable patients. Continuing research efforts are needed to further our understanding of mucositis pathobiology and the pharmacogenomics of toxicity.

Systematic review of agents for the management of gastrointestinal mucositis in cancer patients

PURPOSE

The aim of this study was to review the available literature and define clinical practice guidelines for the use of agents for the prevention and treatment of gastrointestinal mucositis.

METHODS

A systematic review was conducted by the Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO). The body of evidence for each intervention, in each cancer treatment setting, was assigned an evidence level. Based on the evidence level, one of the following three guideline determinations was possible: recommendation, suggestion, and no guideline possible.

RESULTS

A total of 251 clinical studies across 29 interventions were examined. Panel members were able to make one new evidence-based negative recommendation; two new evidence-based suggestions, and one evidence-based change from previous guidelines. Firstly, the panel recommends against the use of misoprostol suppositories for the prevention of acute radiation-induced proctitis. Secondly, the panel suggests probiotic treatment containing Lactobacillus spp., may be beneficial for prevention of chemotherapy and radiotherapy-induced diarrhea in patients with malignancies of the pelvic region. Thirdly, the panel suggests the use of hyperbaric oxygen as an effective means in treating radiation-induced proctitis. Finally, new evidence has emerged which is in conflict with our previous guideline surrounding the use of systemic glutamine, meaning that the panel is unable to form a guideline. No guideline was possible for any other agent, due to inadequate and/or conflicting evidence.

CONCLUSIONS

This updated review of the literature has allowed new recommendations and suggestions for clinical practice to be reached. This highlights the importance of regular updates.

Indigenous Health: ACTION on Prevention - 50th annual Australian Society for Medical Research National Scientific Conference

The 50th annual National Scientific Conference of the Australian Society for Medical Research was held in Cairns, Queensland, 13-16 November 2011. The theme, 'Indigenous Health: ACTION on Prevention' highlighted the direct action being undertaken by health and medical researchers, as well as allied health professionals, to improve long-term health outcomes for Indigenous Australians.

Biochemical and histological changes in the small intestine of mice with dextran sulfate sodium colitis

The dextran sulfate sodium (DSS) model of colitis has been commonly utilized in mice to assess novel treatments for ulcerative colitis. Recent studies have indicated that morphological and biochemical changes extend to the small intestine (SI). This study aimed to characterize histological and biochemical changes in the SI during DSS colitis in wild-type (WT) and DPIV knock-out (DPIV(-/-) ) mice treated with saline or the DPIV inhibitors, Ile-Pyrr-(2-CN)*TFA or Ile-Thia. Groups (n = 10) of DPIV(-/-) and WT mice were orally gavaged twice daily with saline, Ile-Pyrr-(2-CN)*TFA or Ile-Thia. Mice consumed 2% DSS in drinking water for 6 days to induce colitis. Small intestinal tissue was assessed for histological changes, sucrase, and DPIV activity and neutrophil infiltration. Jejunal villus length was increased in all groups after 6 days DSS consumption (P < 0.05). Jejunal DPIV activity was significantly lower by 35% in WT mice receiving Ile-Pyrr-(2-CN)*TFA compared to saline controls. Jejunal MPO activity was significantly increased in the WT + saline and DPIV(-/-)  + saline groups following DSS consumption, compared to WT and DPIV(-/-) controls at day 0. Increased sucrase activity was apparent at day 0 in DPIV(-/-) compared to WT mice (P < 0.05). We conclude that DSS-induced damage is not restricted to the colon, but also extends to the small intestine. Furthermore, reduced or absent DPIV activity resulted in functional adaptations to brush border enzyme activity. DPIV inhibitors are now a recognized therapy for type-II diabetes. The work presented here highlights the need to delineate any long-term effects of DPIV inhibitors on SI function, to further validate their safety and tolerability.

Teduglutide, a glucagon-like peptide-2 analog for the treatment of gastrointestinal diseases, including short bowel syndrome

Glucagon-like peptide-2 (GLP-2) is a potent intestinotrophic growth factor with therapeutic potential for the prevention or treatment of an expanding number of gastrointestinal diseases, including short bowel syndrome (SBS). Teduglutide, being developed by NPS Allelix and licensee Nycomed, is a protease-resistant analog of GLP-2 for the potential treatment of gastrointestinal disease. Teduglutide has prolonged biological activity compared with native GLP-2, and preclinical studies demonstrated significant intestinotrophic activity in models of SBS, experimental colitis and chemotherapy-induced intestinal mucositis. Patients with SBS rely on parenteral nutrition (PN) following bowel resection, and in a phase III clinical trial with teduglutide, > 20% reduction in PN was observed in patients with SBS receiving teduglutide. A phase II clinical trial for teduglutide in Crohn's disease observed remission rates of 55.6% in patients. At the time of publication, phase III clinical trials for SBS were ongoing, as were preclinical studies for chemotherapy-induced mucositis and pediatric indications. Teduglutide represents a novel, efficacious drug capable of increasing intestinal growth and improving intestinal function, and may change clinical management of intestinal disease and damage.

Dipeptidyl peptidase expression during experimental colitis in mice

BACKGROUND

We have previously demonstrated that inhibition of dipeptidyl peptidase (DP) activity partially attenuates dextran sulfate sodium (DSS) colitis in mice. The aim of this study was to further investigate the mechanisms of this protection.

MATERIALS AND METHODS

Wildtype (WT) and DPIV(-/-) mice consumed 2% DSS in drinking water for 6 days to induce colitis. Mice were treated with saline or the DP inhibitors Ile-Pyrr-(2-CN)*TFA or Ile-Thia. DP mRNA and enzyme levels were measured in the colon. Glucagon-like peptide (GLP)-2 and GLP-1 concentrations were determined by radioimmunoassay, regulatory T-cells (Tregs) by fluorescence activated cell sorting (FACS) on FOXp3+T cells in blood, and neutrophil infiltration assessed by myeloperoxidase (MPO) assay.

RESULTS

DP8 and DP2 mRNA levels were increased (P < 0.05) in WT+saline mice compared to untreated WT mice with colitis. Cytoplasmic DP enzyme activity was increased (P < 0.05) in DPIV(-/-) mice at day 6 of DSS, while DP2 activity was increased (P < 0.05) in WT mice with colitis. GLP-1 (63%) and GLP-2 (50%) concentrations increased in WT+Ile-Pyrr-(2-CN)*TFA mice compared to day-0 controls. MPO activity was lower in WT+Ile-Thia and WT+Ile-Pyrr-(2-CN)*TFA treated mice compared to WT+saline (P < 0.001) at day 6 colitis.

CONCLUSIONS

DP expression and activity are differentially regulated during DSS colitis, suggesting a pathophysiological role for these enzymes in human inflammatory bowel disease (IBD). DP inhibitors impaired neutrophil recruitment and maintenance of the Treg population during DSS-colitis, providing further preclinical evidence for the potential therapeutic use of these inhibitors in IBD. Finally, DPIV appears to play a critical role in mediating the protective effect of DP inhibitors.

The use of GLP-2 and related growth factors in intestinal diseases

The pharmacological application of intestinal growth factors has been recognized because of the protective and reparative actions of these factors in the intestinal tract. This review highlights the use of keratinocyte growth factor (KGF), IGF-1 and glucagon-like peptide 2 (GLP-2) in efficacy studies of intestinal damage; the results from these studies support potential clinical applications of these factors in treating intestinal diseases. In particular, GLP-2 has been assessed in preclinical and clinical investigations for its capacity to prevent or treat an increasing number of intestinal diseases, including short bowel syndrome, chemotherapy-induced intestinal mucositis and inflammatory bowel disease.

The herbal extract, Iberogast, improves jejunal integrity in rats with 5-Fluorouracil (5-FU)-induced mucositis

There is an acute need for the development of effective therapies for mucositis, a debilitating side effect of cancer chemotherapy. Iberogast is a herbal extract reported to possess anti-inflammatory properties. We investigated Iberogast for its potential to reduce the severity of 5-Fluorouracil (FU)-induced mucositis in rats. Rats were allocated to three treatment groups (n = 8) and gavaged daily with a 10% solution of Iberogast or water from day 0 to day 8. Rats were injected intraperitoneally with 5-FU (150 mg/kg) or saline on day 6, and killed after 72 h. In vivo and in vitro sucrase activity was assessed by (13)C-sucrose breath test (SBT) and sucrase assay respectively. Intestinal disease severity was determined by histological assessment of villus height and crypt depth. Significant increases in villus height (277 +/- 9 microm) and crypt depth (67 +/- 3 microm) were observed in 5-FU + Iberogast-treated rats compared with 5-FU + Water (224 +/- 13 microm and 48 +/- 2 microm respectively; p < 0.05). Sucrase activity was significantly reduced in all 5-FU groups compared to control. Significant reductions in SBT and sucrase activity were observed in all 5-FU groups compared with Saline + Water controls (p < 0.05). We conclude that although Iberogast partially improved the histopathological features of 5-FU induced mucositis, it conferred no significant protection as indicated by the assessed endpoints.

Growth factor based therapies and intestinal disease: is glucagon-like peptide-2 the new way forward?

Inflammatory bowel disease (IBD) is a chronic, debilitating disease associated with severe damage to the intestinal mucosa. Glucagon-like peptide-2 (GLP-2) is a potent and specific gastrointestinal growth factor that is demonstrating therapeutic potential for the prevention or treatment of an expanding number of intestinal diseases, including short bowel syndrome (SBS), small bowel enteritis and IBD. The biological activity of GLP-2 is limited due to proteolytic inactivation by the protease dipeptidyl peptidase (DP)IV. Inhibitors of DPIV activity may represent a novel strategy to prolong the growth promoting actions of GLP-2. This review outlines evidence for the clinical application of GLP-2, its degradation resistant analogue, Teduglutide, and novel DPIV inhibitors in efficacy studies utilizing pre-clinical models of intestinal damage, in particular IBD.

Effects of Streptococcus thermophilus TH-4 on intestinal mucositis induced by the chemotherapeutic agent 5-Fluorouracil (5-FU)

Beneficial bacteria (probiotics) and probiotic-derived factors have the potential to ameliorate disorders of the intestine. The aim of this study was to compare live Streptococcus thermophilus TH-4 (TH-4), dead TH-4 and TH-4 supernatant in rats treated with 5-Fluorouracil. Rats were randomly allocated to five treatment groups (n = 8–10): Saline + Water; 5-FU + Skim Milk; 5-FU+ Live TH-4; 5-FU + Supernatant TH-4; and 5-FU + Dead TH-4.5-FU (150 mg.kg-1) was administered by a single intraperitoneal injection on day zero; animals were killed on day four. Treatments were administered daily from days -2 to +3 via oro-gastric gavage. Metabolic parameters were measured daily. Blood was obtained by cardiac puncture, and intestinal tissues removed for quantitative and qualitative histological assessment, including: villus height and area; crypt depth and area, mitotic count and crypt fission;biochemical determination of sucrase and myeloperoxidase (MPO)activity; and disease severity scoring. One-way ANOVA statistical analyses were conducted for the majority of outcome measures. Live TH-4 significantly reduced disease severity score by 13% (p< 0.05), and partially normalized mitotic counts compared with 5-FU + Skim Milk controls. Live and Supernatant TH-4 reduced crypt fission by 69% and 48% (p < 0.05), respectively, compared to 5-FU + Skim Milk controls. No significant differences (p > 0.05) in the occurrence of bacteraemia were evident across all groups. Live TH-4 partially normalized mitotic count and histological severity score in 5-FU treated rats. The inhibitory effect of live TH-4 and TH-4 Supernatant on crypt fission suggests therapeutic utility in the prevention of disorders characterized by increased crypt fission,such as colorectal carcinoma.

Effects of Streptococcus thermophilus TH-4 on intestinal mucositis induced by the chemotherapeutic agent, 5-Fluorouracil (5-FU)

Beneficial bacteria (probiotics) and probiotic-derived factors have the potential to ameliorate disorders of the intestine. The aim of this study was to compare live Streptococcus thermophilus TH-4 (TH-4), dead TH-4 and TH-4 supernatant in rats treated with 5-Fluorouracil. Rats were randomly allocated to five treatment groups (n=8-10): Saline+Water; 5-FU+Skim Milk; 5-FU+Live TH-4; 5-FU+Supernatant TH-4; and 5-FU+Dead TH-4. 5-FU (150mg.kg(-1)) was administered by a single intraperitoneal injection on day 0; animals were killed on day 4. Treatments were administered daily from days -2 to 3 via oro-gastric gavage. Metabolic parameters were measured daily. Blood was obtained by cardiac puncture, and intestinal tissues removed for quantitative and qualitative histological assessment, including: villous height and area; crypt depth and area, mitotic count and crypt fission; biochemical determination of sucrase and myeloperoxidase (MPO) activity; and disease severity scoring. One-way ANOVA statistical analyses were conducted for the majority of outcome measures. Live TH-4 significantly reduced disease severity score by 13% (p< 0.05), and partially normalised mitotic counts compared with 5-FU+Skim milk controls. Live and supernatant TH-4 reduced crypt fission by 69% and 48% (p< 0.05), respectively, compared to 5-FU+Skim Milk controls. No significant differences (p> 0.05) in the occurrence of bacteraemia were evident across all groups. Live TH-4 partially normalised mitotic count and histological severity score in 5-FU treated rats. The inhibitory effect of live TH-4 and TH-4 supernatant on crypt fission suggests therapeutic utility in the prevention of disorders characterised by increased crypt fission, such as colorectal carcinoma.

Grape seed extract protects IEC-6 cells from chemotherapy-induced cytotoxicity and improves parameters of small intestinal mucositis in rats with experimentally-induced mucositis

Mucositis is a common side-effect of high-dose chemotherapy regimens. Grape seed extract (GSE) represents a rich source of proanthocyanidins with the potential to decrease oxidative damage and inflammation within the gastrointestinal tract. We evaluated GSE for its capacity to decrease the severity of chemotherapy-induced mucositis in vitro and in vivo. In vitro: GSE was administered to IEC-6 intestinal epithelial cells prior to damage induced by 5-Fluorouracil (5-FU). Cell viability was determined by neutral red assay. In vivo: Female Dark Agouti rats (130-180 g) were gavaged with 1 ml GSE (400 mg/kg) daily (day 3-11) and received 5-FU (150 mg/kg) by intraperitoneal (i.p.) injection on day nine to induce mucositis. Rats were sacrificed at day 12 and intestinal tissues collected for myeloperoxidase and sucrase activity assays and histological analyses. Statistical analysis was performed by one-way ANOVA. GSE prevented the decrease in IEC-6 cell viability induced by 5-FU (p < 0.01). Compared with 5-FU controls, GSE significantly reduced myeloperoxidase activity by 86% and 27% in the proximal jejunum (p < 0.001) and distal ileum (p < 0.05) respectively; decreased qualitative histological scores of damage (p < 0.05) in the proximal jejunum; increased villus height in the proximal jejunum (17%; p < 0.05) and distal ileum (50%; p < 0.01), and attenuated the 5-FU-induced reduction of mucosal thickness by 16% in the jejunum (p < 0.05) and 45% in the ileum (p < 0.01). GSE partially protected IEC-6 cells from 5-FU-induced cytotoxicity and ameliorated intestinal damage induced by 5-FU in rats. GSE may represent a promising prophylactic adjunct to conventional chemotherapy for preventing intestinal mucositis.

Lactobacillus fermentum BR11 and fructo-oligosaccharide partially reduce jejunal inflammation in a model of intestinal mucositis in rats

Although probiotics are beginning to enter mainstream medicine for disorders of the colon, their effects on the small bowel remain largely unexplored. We investigated the recently identified probiotic, Lactobacillus fermentum (L. fermentum) BR11 (BR11) and the prebiotic, fructo-oligosaccharide (FOS), both individually and in synbiotic combination, for their potential to alleviate intestinal mucositis. From Days 0-9, rats consumed skim milk (SM; saline + SM), low dose (LD-BR11; 1 x 10(6)cfu/ml), high dose (HD-BR11; 1 x 10(9)cfu/ml), LD-FOS (3%), HD-FOS (6%), or synbiotic (HD-BR11/FOS). On Day 7, rats were injected with 5-fluorouracil (5-FU; 150 mg/kg). All rats were sacrificed on Day 10. Intestinal tissues were collected for quantitative histology, sucrase, and myeloperoxidase (MPO) determinations. 5-FU decreased sucrase activity, villus height, crypt depth, and crypt cell proliferation compared to controls. Compared to 5-FU + SM, histological damage severity scores were increased for all treatments, although all were effective at reducing jejunal inflammation, indicated by reduced MPO activity (P < 0.05). The combination of BR11 and FOS did not provide additional protection. Moreover, HD-FOS and the synbiotic actually increased clinical mucositis severity (P < 0.05). We conclude that L. fermentum BR11 has the potential to reduce inflammation of the upper small intestine. However, its combination with FOS does not appear to confer any further therapeutic benefit for the alleviation of mucositis.

Inhibiting dipeptidyl peptidase activity partially ameliorates colitis in mice

New treatment strategies are required for the debilitating inflammatory bowel diseases (IBD), Crohn's Disease and Ulcerative Colitis. DP inhibitors can prolong the bioactivity of the potent intestinotrophic growth factor glucagon-like peptide-2 (GLP-2(1-33)). We investigated whether novel inhibitors of DP activity could modify the course of disease activity in the dextran sulfate sodium (DSS) model of colitis. C57BL/6 mice consumed 2 percent DSS in drinking water for 6 days. Mice were orally gavaged twice daily with 0.9% saline, 10 mg/kg isoleucyl-cyano-pyrrolidine (P59/99) or isoleucyl-thiazolidine (P32/98). Assessment of disease severity incorporated a disease activity index (DAI), together with histological assessment of crypt area and depth in the distal colon. DP activity was significantly inhibited at all time points. The DAI was significantly lower in the P59/99 and P32/98 treatment groups compared to saline treatment in all three time courses. Crypt hyperplasia (p<0.05) was observed in the saline group compared to P32/98 treatment at day 9. This preliminary study shows that novel inhibitors of DP activity may provide a new treatment strategy for IBD.

Development and resolution of experimental colitis in mice with targeted deletion of dipeptidyl peptidase IV

Glucagon-like peptide-2 (GLP-2) is a potent intestinotrophic growth factor that enhances repair of damaged intestinal tissue. However, its bioactivity is limited by dipeptidyl peptidase IV (DPIV)-mediated degradation. We hypothesized that DPIV(-/-) mice would display an increased resistance to, and an enhanced recovery from, dextran sulfate sodium (DSS)-induced colitis compared to DPIV(+/+) mice. DPIV(+/+) and DPIV(-/-) mice consumed 2% DSS for 6 days, followed by a 15 day recovery period. Mice were killed at days 0, 3, 6, 9, 14, and 21 (n = 6-8) and the small intestine and colon removed for histological assessment of villus height, crypt depth, and crypt area. The epithelial cell proliferative labeling index was determined by proliferating cell nuclear antigen (PCNA) immunostaining. Small intestine, colon, and total body weight did not differ between DPIV(+/+) and DPIV(-/-) mice. Distal colon crypt depth did not differ significantly between DPIV(+/+) and DPIV(-/-) mice during the development of DSS-colitis or during the recovery phase. Similarly no significant effects were apparent on distal colon crypt area or PCNA labeling index between DPIV(+/+) and DPIV(-/-) during the development of and recovery from DSS-colitis. However, DPIV(-/-) mice still possessed significant levels of plasma DPIV-like activity. We conclude that loss of DPIV activity does not increase resistance to experimental colitis and hypothesize that other DPIV family members may also be involved in the cleavage of GLP-2.

[Primary hypothyroidism in the adult older than 60 years. Characteristics and follow-up after initiation of replacement treatment in hospital]

OBJECTIVE

Primary hypothyroidism is common in the elderly. Yet its care remains unclear.

PATIENTS AND METHODS

Clinical, biological characteristics and outcome of 45 patients aged over 60 years admitted for in-hospital initiation of treatment for primary hypothyroidism were recorded. Causes and tolerance of treatment (clinical and ECG monitoring in hospital) were seek for.

RESULTS

Initial symptoms, predominantly fatigue (84.4%), were moderate, contrasting with severe biological hormonal deficiency. The most common routine biological change was hypercholesterolemia (57.6%). Female predominance was obvious (77.8%) and the most usual aetiology autoimmune chronic thyroiditis. Despite variability of symptoms, long term follow-up demonstrates a positive response to treatment, including an improvement in fatigue, eye-lid swelling, bradycardia and overweight. This clinical improvement was achieved on an average dose of 1.22 +/- 0.47 mg/kg/day L-T4 in order to maintain normal TSH (3.76 +/- 2.93 mUI/l). Cardiovascular incidents while starting treatment require experienced care and low dose initial treatment.

CONCLUSION

Primary hypothyroidism is still lately discovered in the elderly. Yet, since treatment is efficacious and simple, the disease should be searched for and cared after whenever a related symptom occurs.

[Carbimazole and leukocytoclastic vasculitis: apropos of a case]

INTRODUCTION

The authors describe the case of biopsy-proven cutaneous leukocytoclastic vasculitis secondary to treatment with carbimazole.

EXEGESIS

A 78-year-old white female developed erythematous macules on the lower limbs which cleared after discontinuation of her current treatment and implementation of oral steroid therapy. Causal explorations (lack of systemic disorder or infectious disease) remain negative, except for positive immune complexes. This case clearly differs from the two cases of microvasculitis (myositis and nephritis) secondary to treatment with carbimazole previously mentioned in the literature.

CONCLUSION

To our knowledge this is the first report of biopsy-proven cutaneous leukocytoclastic vasculitis associated with this antithyroid agent. Its widespread use makes awareness of the side-effect important.