Wim J. E. Tissing

The Role of Intestinal Microbiota in the Development and Severity of Chemotherapy-Induced Mucositis

Mucositis, also referred to as mucosal barrier injury, is one of the most debilitating side effects of radiotherapy and chemotherapy treatment. Clinically, mucositis is associated with pain, bacteremia, and malnutrition. Furthermore, mucositis is a frequent reason to postpone chemotherapy treatment, ultimately leading towards a higher mortality in cancer patients. According to the model introduced by Sonis, both inflammation and apoptosis of the mucosal barrier result in its discontinuity, thereby promoting bacterial translocation. According to this five-phase model, the intestinal microbiota plays no role in the pathophysiology of mucositis. However, research has implicated a prominent role for the commensal intestinal microbiota in the development of several inflammatory diseases like inflammatory bowel disease, pouchitis, and radiotherapy-induced diarrhea. Furthermore, chemotherapeutics have a detrimental effect on the intestinal microbial composition (strongly decreasing the numbers of anaerobic bacteria), coinciding in time with the development of chemotherapy-induced mucositis. We hypothesize that the commensal intestinal microbiota might play a pivotal role in chemotherapy-induced mucositis. In this review, we propose and discuss five pathways in the development of mucositis that are potentially influenced by the commensal intestinal microbiota: 1) the inflammatory process and oxidative stress, 2) intestinal permeability, 3) the composition of the mucus layer, 4) the resistance to harmful stimuli and epithelial repair mechanisms, and 5) the activation and release of immune effector molecules. Via these pathways, the commensal intestinal microbiota might influence all phases in the Sonis model of the pathogenesis of mucositis. Further research is needed to show the clinical relevance of restoring dysbiosis, thereby possibly decreasing the degree of intestinal mucositis.

Recommendations for Cardiomyopathy Surveillance for Survivors of Childhood Cancer: A Report from the International Late Effects of Childhood Cancer Guideline Harmonization Group

Survivors of childhood cancer treated with anthracycline chemotherapy or chest radiation are at an increased risk of developing congestive heart failure. In this population, congestive heart failure is well recognised as a progressive disorder, with a variable period of asymptomatic cardiomyopathy that precedes signs and symptoms. As a result, several clinical practice guidelines have been developed independently to help with detection and treatment of asymptomatic cardiomyopathy. These guidelines differ with regards to definitions of at-risk populations, surveillance modality and frequency, and recommendations for interventions. Differences between these guidelines could hinder the effective implementation of these recommendations. We report on the results of an international collaboration to harmonise existing cardiomyopathy surveillance recommendations using an evidence-based approach that relied on standardised definitions for outcomes of interest and transparent presentation of the quality of the evidence. The resultant recommendations were graded according to the quality of the evidence and the potential benefit gained from early detection and intervention.

Chemotherapy Treatment in Pediatric Patients with Acute Myeloid Leukemia Receiving Antimicrobial Prophylaxis Leads to a Relative Increase of Colonization with Potentially Pathogenic Bacteria in the Gut

BACKGROUND Normally, humans are protected against infections by their anaerobic intestinal microorganisms providing colonization resistance. In immunocompromised patients, the endogenous intestinal gram-positive and gram-negative pathogens often cause infectious complications. Therefore, we analyzed the effect of chemotherapy treatment and antimicrobial prophylaxis on intestinal bacterial populations (microbiota) among pediatric patients with acute myeloid leukemia who are prone to intestinal mucositis and infections. METHODS During 36 chemotherapy cycles, fecal samples were collected from pediatric patients with acute myeloid leukemia. Fecal bacterial populations were analyzed by polymerase chain reaction denaturing gradient gel electrophoresis fingerprinting. Fluorescent in situ hybridization analysis with specific bacterial oligonucleotide probes was used to quantify the fecal bacteria. RESULTS During chemotherapy treatment, the total number of bacteria in fecal samples was 10(9) per gram of dry weight feces, which was 100-fold lower than than in healthy control samples. Fluorescent in situ hybridization analysis showed that this decrease was the result of an up to 10,000-fold decrease in anaerobic bacteria, partly compensated for by a 100-fold increase in potentially pathogenic enterococci. Additional experiments showed that both prophylactic and therapeutic use of antibiotics could not sufficiently explain the tremendous changes in intestinal microbial composition. In vitro tests showed a direct bacteriostatic effect of chemotherapeutics. CONCLUSIONS Patients with acute myeloid leukemia treated with chemotherapy and prophylactic antibiotics are unable to maintain colonization resistance because of a decrease in anaerobic bacteria and an increase in potentially pathogenic aerobic enterococci. We hypothesize that this disturbance in the balance between anaerobic and aerobic bacteria will further increase the risk of gram-positive aerobic infections among immunocompromised patients with cancer.

Expression and structural analysis of glucocorticoid receptor isoform gamma in human leukaemia cells using an isoform-specific real-time polymerase chain reaction approach

Summary. Glucocorticoids are broadly used for chemotherapy in childhood acute lymphoblastic leukaemia (ALL). The intracellular effects of glucocorticoids are mediated through the glucocorticoid receptor. The human glucocorticoid receptor gamma isoform (hGR‐gamma) differs from the main isoform (hGR‐alpha) by an additional amino acid within the DNA binding domain of the receptor protein. This may decrease hGR‐alpha‐mediated transcriptional activation. The importance of hGR‐gamma expression in childhood ALL is unknown. To evaluate hGR‐gamma mRNA expression levels, a real‐time polymerase chain reaction (PCR)‐based approach, allowing the selective amplification of hGR‐gamma, was developed and optimized. We were able to demonstrate target selectivity of hGR‐gamma amplification using sequence‐specific primers. Studying the structure of the 3′ end of hGR‐gamma, a combination of this isoform with other hGR isoforms could be demonstrated. Using analysis of hGR‐gamma‐specific amplification in comparison with the expression of hGR‐total (all isoforms) in leukaemic blasts from patients with either a good response to prednisone (PGR) or poor‐prednisone response (PPR) in vivo, relative hGR‐gamma expression was observed to be lower in cells from patients with PGR compared with PPR, in particular after 10 h of dexamethasone stimulation. These data were correlated with cell survival, demonstrating a more pronounced induction of apoptosis in cells from patients with PGR as compared with PPR.

A prospective study on drug monitoring of PEGasparaginase and Erwinia asparaginase and asparaginase antibodies in pediatric acute lymphoblastic leukemia.

This study prospectively analyzed the efficacy of very prolonged courses of pegylated Escherichia coli asparaginase (PEGasparaginase) and Erwinia asparaginase in pediatric acute lymphoblastic leukemia (ALL) patients. Patients received 15 PEGasparaginase infusions (2500 IU/m(2) every 2 weeks) in intensification after receiving native E coli asparaginase in induction. In case of allergy to or silent inactivation of PEGasparaginase, Erwinia asparaginase (20 000 IU/m(2) 2-3 times weekly) was given. Eighty-nine patients were enrolled in the PEGasparaginase study. Twenty (22%) of the PEGasparaginase-treated patients developed an allergy; 7 (8%) showed silent inactivation. The PEGasparaginase level was 0 in all allergic patients (grade 1-4). Patients without hypersensitivity to PEGasparaginase had serum mean trough levels of 899 U/L. Fifty-nine patients were included in the Erwinia asparaginase study; 2 (3%) developed an allergy and none silent inactivation. Ninety-six percent had at least 1 trough level ≥100 U/L. The serum asparagine level was not always completely depleted with Erwinia asparaginase in contrast to PEGasparaginase. The presence of asparaginase antibodies was related to allergies and silent inactivation, but with low specificity (64%). Use of native E coli asparaginase in induction leads to high hypersensitivity rates to PEGasparaginase in intensification. Therefore, PEGasparaginase should be used upfront in induction, and we suggest that the dose could be lowered. Switching to Erwinia asparaginase leads to effective asparaginase levels in most patients. Therapeutic drug monitoring has been added to our ALL-11 protocol to individualize asparaginase therapy.

Genetic Variations in the Glucocorticoid Receptor Gene Are Not Related to Glucocorticoid Resistance in Childhood Acute Lymphoblastic Leukemia

Glucocorticoid sensitivity is an important prognostic factor in pediatric acute lymphoblastic leukemia (ALL). For its antileukemic effect, glucocorticoid binds the intracellular glucocorticoid receptor (GR) subsequently regulating transcription of downstream genes. We analyzed whether genetic variations within the GR gene are related to differences in the cellular response to glucocorticoids. Methods: In leukemic samples of 57 children, the GR gene was screened for nucleotide variations using a PCR/single-strand conformational polymorphism sequencing strategy. Data were linked to in vivo and in vitro glucocorticoid resistance. Results: No somatic mutations were detected in the GR gene coding region, but six polymorphisms (i.e., ER22/23EK, N363S, BclI, intron mutation 16 bp upstream of exon 5, H588H, and N766N) were identified. In 67% of ALL cases, at least one minor allele of these polymorphisms was detected. Although only borderline significant, the incidence for the N363S polymorphism minor allele was higher (12% versus 6%, P = 0.06) and for the ER22/23EK minor allele lower (4% versus 7.6%, P = 0.1) than in a healthy, comparable population. The different genotypes of the polymorphisms were not related to prednisone resistance. In conclusion, polymorphisms but not somatic mutations in the GR gene coding region occur in leukemic blasts of children with ALL. Our data suggest that these genetic variations are not a major contributor for differences in cellular response to glucocorticoids in childhood ALL. The higher incidence of the N363S minor allele and the lower incidence of the ER22/23EK minor allele in our ALL population as compared with a normal population warrants further research.

Citrulline as a Marker for Chemotherapy Induced Mucosal Barrier Injury in Pediatric Patients

The currently used National Cancer Institute (NCI) adverse events criteria for mucosal barrier injury (MBI) are insufficient for use in children. We searched for objective, easily measurable indicators for MBI in children with cancer.

Systematic review of amifostine for the management of oral mucositis in cancer patients

PurposeThe aim of this study was to review the available literature from 1966 until December 31, 2010 and define clinical practice guidelines for the use of amifostine for the prevention and treatment of oral mucositis in cancer patients.MethodsA systematic review was conducted by the Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology. The body of evidence for the use of amifostine, 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, or no guideline possible.ResultsThirty papers were reviewed for evidence on amifostine as an intervention for oral mucositis. No guideline was possible for amifostine in any cancer treatment setting due to inadequate and conflicting evidence.ConclusionReview of the amifostine studies for the prevention and treatment of oral mucositis has found insufficient evidence to support its use in any cancer treatment setting for this purpose. Additional well-designed research is needed to clarify the role of amifostine as an intervention for oral mucositis.

Malnutrition in childhood cancer patients: A review on its prevalence and possible causes

PURPOSE To perform a systematic literature review for critical evaluation of prevalence and factors contributing to malnutrition in childhood cancer. METHODS A systematic search resulting in 46 suitable articles. RESULTS Due to lack of uniform criteria and adequate studies, the prevalence rates of malnutrition can only be estimated. Based on strengths and weaknesses of included references, prevalence rates are estimated to be 0-10% for leukemia, 20-50% for neuroblastoma, and 0-30% for other malignancies. Whether energy deficiency or inflammation contributed to malnutrition could not be confirmed because the occurrence of energy deficit (low energy intake, increased metabolic rate) or inflammation (related to cachexia) was not convincing. Also, a relationship between these factors and malnutrition was not studied. CONCLUSION Longitudinal studies are needed to determine which children are at risk of malnutrition, and to investigate the impact of energy deficiency and inflammation on the nutritional status and body composition of childhood cancer patients.

Systolic and diastolic dysfunction in long-term adult survivors of childhood cancer.

AIM To assess systolic and diastolic function in adult childhood-cancer survivors (CCS) after treatment entailing potential cardiovascular toxicity. METHODS The study cohort consisted of 277 adult CCS (median age 28 [range 18-48]years), who had been treated with anthracyclines, platinum, and/or radiotherapy between 1976 and 1999, along with 130 healthy sibling controls. The assessments included echocardiography, baroreflex sensitivity measurement, and plasma N-terminal pro-brain natriuretic peptide (NT-proBNP). Echocardiography measurements were shortening fraction (SF) (abnormal<29%) for systolic function and tissue velocity imaging of early diastole (TVI Et) (abnormal<8.00)cm/sec for diastolic function; systolic function was also assessed by the wall motion score index (WMSI). RESULTS At 18 (5-31)years post-treatment, the prevalence of both impaired SF and abnormal WMSI was increased in CCS compared to controls (p=0.003 and p<0.001, respectively). CCS also had an increased prevalence of diastolic dysfunction compared to the controls (12% versus 1%, p<0.001). Abnormal SF and/or abnormal diastolic function were found in 43% of CCS. NT-proBNP was higher in CCS and was associated to increased WMSI. Baroreflex sensitivity was lower in CCS and was associated with diastolic dysfunction. Systolic as well as diastolic dysfunction was associated with cumulative dose of anthracyclines and mediastinal irradiation. CONCLUSION After treatment with potential cardiovascular toxic therapies, the risk of systolic and diastolic dysfunction in CCS is considerable. Since these abnormalities, in particular diastolic dysfunction, are age related, the observed effects might be considered a sign of precocious cardiac ageing.