Gastro-intestinal toxicity related to bone marrow transplantation: disruption of the intestinal barrier precedes clinical findings

Nutrition support and clinical outcomes following allogeneic stem cell transplantation

Nutrition support is frequently required post allogeneic stem cell transplantation (SCT) and while there is some evidence on the benefits of enteral nutrition (EN), parenteral nutrition (PN) is widely used in practice. The study aimed to examine the impact of EN versus PN on early outcomes following SCT. All patients who underwent allogeneic SCT over 2.5 years were included in the analysis. Data was retrospectively collected on mode of nutrition support with clinical outcome data obtained from an existing database. Clinical outcomes were compared between groups by logistic, poisson and negative binomial regression, with adjustment for baseline confounders as appropriate. Patients who received EN then changed to PN had a longer length of hospital stay compared to those who received EN only (IR 1.24, 95% CI: 1.11-1.38, p < 0.001). Compared to those who received EN only, patients who received EN that changed to PN or PN only had a longer time to neutrophil engraftment (IR 1.11, 95% CI: 1.02-1.20, p = 0.016 and IR 1.16, 95% CI: 1.03-1.30, p = 0.017) and platelet engraftment (IR 1.20, 95% CI 1.08-1.33, p < 0.001 and IR 1.24, 95% CI 1.08-1.42, p = 0.002). Enteral nutrition should be first line nutritional support for patients undergoing allogeneic SCT.

Intestinal permeability in patients undergoing stem cell transplantation correlates with systemic acute phase responses and dysbiosis

Intestinal permeability may correlate with adverse outcomes during hematopoietic stem cell transplantation (HSCT), but longitudinal quantification with traditional oral mannitol and lactulose is not feasible in HSCT recipients because of mucositis and diarrhea. A modified lactulose:rhamnose (LR) assay is validated in children with environmental enteritis. Our study objective was to quantify peri-HSCT intestinal permeability changes using the modified LR assay. The LR assay was administered before transplant, at day +7 and +30 to 80 pediatric and young adult patients who received allogeneic HSCT. Lactulose and rhamnose were detected using urine mass spectrometry and expressed as an L:R ratio. Metagenomic shotgun sequencing of stool for microbiome analyses and enzyme-linked immunosorbent assay analyses of plasma lipopolysaccharide binding protein (LBP), ST2, REG3α, claudin1, occludin, and intestinal alkaline phosphatase were performed at the same timepoints. L:R ratios were increased at day +7 but returned to baseline at day +30 in most patients (P = .014). Conditioning regimen intensity did not affect the trajectory of L:R (P = .39). Baseline L:R ratios did not vary with diagnosis. L:R correlated with LBP levels (r2 = 0.208; P = .0014). High L:R ratios were associated with lower microbiome diversity (P = .035), loss of anaerobic organisms (P = .020), and higher plasma LBP (P = .0014). No adverse gastrointestinal effects occurred because of LR. Intestinal permeability as measured through L:R ratios after allogeneic HSCT correlates with intestinal dysbiosis and elevated plasma LBP. The LR assay is well-tolerated and may identify transplant recipients who are more likely to experience adverse outcomes.

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.

Early remodeling of the colonic mucosa after allogeneic hematopoietic stem cells transplantation: An open-label controlled pilot study on 19 patients

BACKGROUND

Graft-versus-host disease (GVHD), particularly acute digestive GVHD (aDGVHD), is a severe complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). It is necessary to identify predictive factors of GVHD to adapt prophylactic treatment.

OBJECTIVE

In this context, our pilot study aimed (i) to determine whether an early remodeling of the colonic mucosa occurred after allo-HSCT and (ii) to identify potential predictive mucosal markers of aDGVHD after allo-HSCT.

METHODS

Between day 21 and day 28 after the allo-HSCT, 19 allo-HSCT patients were included and had a rectosigmoidoscopy with probe-based confocal laser endomicroscopy (pCLE) recording and biopsies. Sixteen patients were included in the control group. Morphological (pCLE), functional (intestinal permeability), and inflammatory parameters (cytokine multiplex immunoassay) were assessed.

RESULTS

Among allo-HSCT patients, 11 patients developed GVHD, and 6 of them developed aDGVHD. Morphological and functional changes of the colonic mucosa occurred after allo-HSCT. Indeed, the perimeter of colonic crypts was significantly increased in allo-HSCT patients compared to controls as well as crypt lumen fluorescein leakage (53% vs. 9%), whereas crypts sphericity, roundness, Feret diameter, and mean vessel area were significantly decreased in allo-HSCT patients compared to the control group. In addition, interleukin-6 (IL-6), IL-33, and IL-15 levels in the supernatants of 24 h explant cultures of colonic biopsies were significantly increased in allo-HSCT patients compared to controls. Finally, there was no difference in pCLE parameters, intestinal permeability, and inflammatory cytokines between patients who developed aDGVHD and those who did not.

CONCLUSION

This pilot study identified early colonic mucosa remodeling after allo-HSCT conditioning therapy, that is morphological and functional mucosal alterations as well as mucosal inflammation. As to whether these changes are first steps in GVHD initiation and could be considered as predictive biomarkers of aDGVHD need to be determined in a larger cohort of patients.

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.

Vitamins and minerals intake adequacy in hematopoietic stem cell transplant: results of a randomized controlled trial

Micronutrient intake among hematopoietic stem cell transplant (HSCT) recipients is poorly studied. This randomized control trial (RCT) assessed the effect of nutritional counseling on micronutrient intake post HSCT. Patients with hematological malignancies receiving HSCT were randomized at hospital discharge into an intervention group (IG) and a control group (CG) between 2016 and 2017. IG received individualized nutritional counseling in the first 3 months post HSCT while CG received general qualitative education without reinforcement. At assessment points (hospital admission, discharge, 30, 60, and 100 days post HSCT termed T4), 24-h recalls were analyzed, and micronutrient intake was compared to patients' individual needs. Results were reported as percentages of dietary reference intake. Groups (IG, n = 22 and CG, n = 24) had similar characteristics pre HSCT. Copper and α-tocopherol intake at T4 were significantly better in IG. Many B vitamins, vitamin C, Manganese, Potassium, Zinc, and vitamin K improved in IG only at T4 compared to baseline intake. Median vitamin D intake remained low in both groups with <20% of patients meeting their individual needs post HSCT. In conclusion, counseling was associated with a trend of improved micronutrient intake. Vitamin D levels remained low irrespective of counseling.

Nutrition Issues in Hematopoietic Stem Cell Transplantation: State of the Art

There have been many changes in hematopoietic stem cell transplantation (HSCT) that affect the patient's nutrition support. In the early 1970s, allogeneic transplants were the most common types of HSCTs; today, autologous transplants are the most common. Bone marrow, peripheral blood, and umbilical cord blood all now serve as sources of stem cells. Conditioning therapies include myeloablative, reduced-intensity myeloablative, and nonmyeloablative regimens. New medications are being developed and used to minimize the toxicities of the conditioning therapy and to minimize infectious complications. Supportive therapies for renal and liver complications have changed. In the past, HSCT patients received parenteral nutrition (PN) throughout their hospitalization and sometimes as home therapy. Because of medical complications and cost issues associated with PN, many centers are now working to use less PN and increase use of enteral nutrition. The immunosuppressed diet has changed from a sterile diet prepared under laminar-flow hoods to a more liberal diet that avoids high-risk foods and emphasizes safety in food handling practices. This article will review these changes in HSCT and the impact of these changes on the nutrition support of the patient.

ATM gene single nucleotide polymorphisms predict regimen-related gastrointestinal toxicity in patients allografted after reduced conditioning

Polymorphisms of genes involved in innate and adaptive immunity have become an object of major interest in regard to hematopoietic stem cell transplantation (HSCT) complications. Regimen-related gastrointestinal toxicity (RR-GIT) is the dominant complication during the pre-engraftment period and has been linked to increased risk of graft-versus-host disease (GVHD) development. According to our hypothesis, functional variants of genes participating in DNA damage response (DDR) may have an impact on the extent of tissue damage caused by the conditioning regimen. In our single-center study, we analyzed 62 patients who underwent HSCT from HLA-identical donors after reduced conditioning. The patients were genotyped for 5 single nucleotide polymorphisms (SNPs, rs4585 T/G, rs189037 A/G, rs227092 T/G, rs228590 C/T, and rs664677 T/C) of the ATM gene-the essential member of the DDR pathways, using allele-specific matrix-assisted laser desorption/ionization, time-of-flight (MALDI-TOF) mass spectrometry assay. Because of almost absolute linkage disequilibrium observed among all 5 SNPs, association of 2 major ATM haplotypes (ATM1/ATM2) with RR-GIT and acute GVHD (aGVHD) was analyzed. Importantly, the univariate and multivariate analysis showed that patients homozygous for ATM2 haplotype (rs4585*T, rs189037*A, rs227092*T, rs228590*C, and rs664677*T) are more likely to suffer from high-grade RR-GIT than ATM1 homozygous patients. The association with aGVHD was not significant. To our knowledge, this is the first report showing the ATM gene variability in relation to RR-GIT in the allogeneic HSCT setting.

Recipient NK cell inactivation and intestinal barrier loss are required for MHC-matched graft-versus-host disease

Previous studies have shown a correlation between pretransplant conditioning intensity, intestinal barrier loss, and graft-versus-host disease (GVHD) severity. However, because irradiation and other forms of pretransplant conditioning have pleiotropic effects, the precise role of intestinal barrier loss in GVHD pathogenesis remains unclear. We developed GVHD models that allowed us to isolate the specific contributions of distinct pretransplant variables. Intestinal damage was required for the induction of minor mismatch [major histocompatibility complex (MHC)-matched] GVHD, but was not necessary for major mismatch GVHD, demonstrating fundamental pathogenic distinctions between these forms of disease. Moreover, recipient natural killer (NK) cells prevented minor mismatch GVHD by limiting expansion and target organ infiltration of alloreactive T cells via a perforin-dependent mechanism, revealing an immunoregulatory function of MHC-matched recipient NK cells in GVHD. Minor mismatch GVHD required MyD88-mediated Toll-like receptor 4 (TLR4) signaling on donor cells, and intestinal damage could be bypassed by parenteral lipopolysaccharide (LPS) administration, indicating a critical role for the influx of bacterial components triggered by intestinal barrier loss. In all, the data demonstrate that pretransplant conditioning plays a dual role in promoting minor mismatch GVHD by both depleting recipient NK cells and inducing intestinal barrier loss.

Efficacy of Enteral Supplementation Enriched with Glutamine, Fiber, and Oligosaccharide on Mucosal Injury following Hematopoietic Stem Cell Transplantation

The combination of glutamine, fiber and oligosaccharides (GFO) is thought to be beneficial for alleviating gastrointestinal mucosal damage caused by chemotherapy. A commercial enteral supplementation product (GFO) enriched with these 3 components is available in Japan. We performed a retrospective study to test whether oral GFO decreased the severity of mucosal injury following hematopoietic stem cell transplantation (HSCT). Of 44 HSCT patients, 22 received GFO and 22 did not. Severity of diarrhea/mucositis, overall survival, weight loss, febrile illness/documented infection, intravenous hyperalimentation days/hospital days, engraftment, acute and chronic GVHD, and cumulative incidence of relapse were studied. Sex, age, performance status, diagnosis, disease status, and treatment variables were similar in both groups. There were fewer days of diarrhea grade 3–4 in patients receiving GFO than in those who did not (0.86 vs. 3.27 days); the same was true for days of mucositis grade 3–4 (3.86 vs. 6.00 days). Survival at day 100 was 100% in the GFO group, but only 77.3% for the patients not receiving GFO (p = 0.0091, log-rank test). Weight loss and the number of days of intravenous hyperalimentation were better in the GFO group (p < 0.001 and p = 0.0014, respectively). Although not significant, less gut bacterial translocation with Enterococcus species developed in the GFO group (p = 0.0728) than in the non-GFO group. Other outcomes were not affected. To the best of our knowledge, this is the first comparative clinical study of GFO supplementation to alleviate mucosal injury after allo-HSCT. We conclude that glutamine, fiber and oligosaccharide supplementation is an effective supportive therapy to decrease the severity of mucosal damage in HSCT.

Intestinal response to myeloablative chemotherapy in piglets

Chemotherapy-induced myeloablation prior to allogeneic hematopoietic stem cell transplantation (HSCT) may be associated with severe toxicity. The current understanding of the pathophysiology of oral and gastrointestinal (GI) toxicity is largely derived from studies in rodents and very little is known from humans, especially children. We hypothesized that milk-fed piglets can be used as a clinically relevant model of GI-toxicity related to a standard conditioning chemotherapy (intravenous busulfan, Bu plus cyclophosphamide, Cy) used prior to HSCT. In study 1, dose-response relationships were investigated in three-day-old pigs (Landrace × Yorkshire × Duroc, n = 6). Pigs were given one of three different dose combinations of Bu and Cy (A: 4 days Bu, 2 × 1.6 mg/kg plus 2 days Cy, 60 mg/kg; B: 4 days Bu, 2 × 0.8 mg/kg plus 2 days Cy, 30 mg/kg; C: 2 days Bu at 2 × 1.6 mg/kg plus 1 day Cy, 60 mg/kg) and bone marrow was collected on day 11. Histology of bone marrow samples showed total aplasia after treatment A. Using this treatment in study 2, Bu-Cy pigs showed lowered spleen and intestinal weights and variable clinical signs of dehydration, sepsis, and pneumonia at tissue collection. Oral mucositis was evident as ulcers in the soft palate in 4/9 Bu-Cy pigs and villus height and brush-border enzyme activities were reduced, especially in the proximal intestine. There were no consistent effects on tissue cytokine levels (IL-8, IL-6, IL-1β, TNF-α) or blood chemistry values (electrolytes, liver transaminases, bilirubin, alkaline phosphatase), except that blood iron levels were higher in Bu-Cy pigs. We conclude that a myeloablative Bu-Cy regimen to piglets results in clinical signs comparable to those seen in pediatric patients subjected to myeloablative treatment prior to HSCT. Piglets may be used as a model for investigating chemotherapy-induced toxicity and dietary and medical interventions.

Infections in Leukemia and Hematopoietic Stem Cell Transplantation

Infections are one of the most common complications in patients diagnosed with leukemia and serve as a major obstacle to treatment. Through the early 1970s, infections were the most common cause of death in patients diagnosed with acute leukemia, but improvement in treatment and supportive care over the past few decades, coupled with expanded prophylaxis and prevention regimens, have led to reduction in both the frequency and severity of infections. Regardless, due in part to an aging cancer population and the diversity of cancer treatments and procedures, infectious diseases remain a major cause of morbidity and mortality in patients with leukemia.

Incidence and risk factors for lower alimentary tract mucositis after 1529 courses of chemotherapy in a homogenous population of oncology patients: clinical and research implications

BACKGROUND

Lower alimentary tract mucositis is a serious complication of chemotherapy. The aim of the study was to determine the incidence, risk factors, and mortality of lower alimentary tract mucositis in a homogeneous population of patients with newly diagnosed myeloma receiving similar antineoplastic therapy and standardized supportive care.

METHODS

Lower alimentary tract mucositis was evaluated among 303 consecutive patients with myeloma (2004-2007) enrolled in a clinical trial consisting of induction chemotherapy, tandem melphalan-based autologous stem cell transplantation (ASCT), and consolidation. Lower alimentary tract mucositis was defined as neutropenia-associated grade II-IV enteritis/colitis. Pretreatment risk factors were examined including body surface area (BSA), serum albumin (albumin), and estimated creatinine clearance (CrCl). Multiple logistic regression model was used to compute adjusted odds ratio (OR) and 95% confidence intervals (CI).

RESULTS

Forty-seven (15.5%) patients developed lower alimentary tract mucositis during 1529 courses of chemotherapy (including 536 melphalan-based ASCT). Pre-enrollment BSA <2 m² (OR, 2.768; 95% CI, 1.200-6.381; P = .0169) increased the risk for lower alimentary tract mucositis, whereas higher albumin was protective (OR, 0.698; 95% CI, 0.519-0.940; P = .0177). Pretransplant variables associated with lower alimentary tract mucositis were BSA <2 m² (OR, 4.451; 95% CI, 1.459-13.58, P = .0087) and estimated CrCl <60 mL/min (OR, 3.493; 95% CI, 1.173-10.40; P = .0246). Higher albumin level conferred protection (OR, 0.500; 95% CI, 0.304-0.820; P = .0061). No lower alimentary tract mucositis-related death was observed.

CONCLUSIONS

Lower alimentary tract mucositis is not uncommon among a homogenous population of oncology patients undergoing sequential courses of chemotherapy including melphalan-based ASCT but does not contribute to mortality. Lower BSA, renal function, and albumin are associated with increased risk for lower alimentary tract mucositis.

Intestinal damage determines the inflammatory response and early complications in patients receiving conditioning for a stem cell transplantation

Background

Stem cell transplantation (SCT) is still complicated by the occurrence of fever and inflammatory complications attributed to neutropenia and subsequent infectious complications. The role of mucosal barrier injury (MBI) of the intestinal tract therein has received little attention.

Methods

We performed a retrospective analysis in 163 SCT recipients of which data had been collected prospectively on intestinal damage (citrulline), inflammation (C-reactive protein), and neutrophil count. Six different conditioning regimens were studied; 5 myeloablative (MA) and 1 non-myeloablative (NMA). Linear mixed model multivariate and AUC analyses were used to define the role of intestinal damage in post-SCT inflammation. We also studied the relationship between the degree of intestinal damage and the occurrence of early post-SCT complications.

Results

In the 5 MA regimen there was a striking pattern of inflammatory response that coincided with the occurrence of severe intestinal damage. This contrasted with a modest inflammatory response seen in the NMA regimen in which intestinal damage was limited. With linear mixed model analysis the degree of intestinal damage was shown the most important determinant of the inflammatory response, and both neutropenia and bacteremia had only a minor impact. AUC analysis revealed a strong correlation between citrulline and CRP (Pearson correlation r = 0.96). Intestinal damage was associated with the occurrence of bacteremia and acute lung injury, and influenced the kinetics of acute graft-versus-host disease.

Conclusion

The degree of intestinal damage after myeloablative conditioning appeared to be the most important determined the inflammatory response following SCT, and was associated with inflammatory complications. Studies should explore ways to ameliorate cytotoxic therapy-induced intestinal damage in order to reduce complications associated with myeloablative conditioning therapy.

Nutrition, anthropometry, gastrointestinal dysfunction, and circulating levels of tumour necrosis factor alpha receptor I and interleukin-1 receptor antagonist in children during stem cell transplantation

To evaluate anthropometry, nutrition and gastrointestinal dysfunction, and to characterize the relation between these parameters and the inflammatory activity evaluated by plasma levels of soluble tumour necrosis factor alpha receptor I (sTNFRI) and interleukin-1 receptor antagonist (IL-1Ra) levels during stem cell transplantation (SCT) in children. Clinical assessments and blood sampling were performed on days -3, 0, +7, +15 and +31 in eight children undergoing SCT. Energy intake, anthropometry, gastrointestinal dysfunction (WHO toxicity score) and sTNFRI and IL-1Ra were evaluated. The energy intake was below recommended levels. There was a loss of lean body mass (arm muscle area)(median, 2031 mm(2) (day -3) vs 1477 mm(2) (day 31); p = 0.04), and of fat mass (arm fat area) (791 mm(2) (day -3) vs 648 mm(2) (day +31); p = 0.04). sTNFRI was elevated throughout the course of transplantation, and peaked after the day of graft infusion (day 0). sTNFRI levels at day 0 predicted changes in weight SDS (r = 0.65; p = 0.05), triceps skinfold SDS (r = 0.85; p = 0.007) and gastrointestinal dysfunction (r = 0.88; p = 0.004). Likewise, IL-1Ra levels at day 0 correlated with the gastrointestinal dysfunction (r = 0.83; p = 0.01) and with the change in weight SDS (r = 0.77; p = 0.03). This study suggests that pretransplant levels of inflammatory markers are associated with posttransplant symptoms of gastrointestinal dysfunction and loss of both fat and lean body mass. Future studies should address if the use of conditioning regimens with limited proinflammatory cytokine inducing activity, anti-inflammatory agents, or more optimised nutritional support can reduce the burden of such posttransplant complications.

Gut protection by palifermin during autologous haematopoietic SCT

Conditioning therapy in connection with haematopoietic SCT (HSCT) induces a disruption of the intestinal barrier function facilitating the permeation of bacteria and endotoxin through the bowel wall with subsequent increased risk of septicaemia and a worsening of GVHD in the allogeneic setting. Palifermin (recombinant human keratinocyte growth factor) reduces the severity of oral mucositis with HSCT. The present trial investigates its effect on intestinal barrier function. Seventeen lymphoma patients undergoing autologous HSCT received palifermin. Intestinal permeability was assessed before the conditioning therapy and on days +4 and +14. Clinical oral and gastrointestinal toxicity was prospectively assessed in parallel. A comparison was made with matched historical study patients (n=21). Patients treated with palifermin had a significantly better preserved intestinal barrier function (P=0.01 on day +4) and were in less need of total parenteral nutrition (P=0.005) as compared with controls. No significant reduction of clinical gastrointestinal or oral toxicity was observed. The intestinal barrier function, normally disrupted by the conditioning therapy, is preserved by palifermin. Whether intestinal barrier preservation protects from invasive infections, and in the allogeneic setting diminishes GVHD severity, remains to be investigated in randomized controlled trials.

Gut toxicity during hemopoietic stem cell transplantation may predict acute graft-versus-host disease severity in patients

Graft-versus-host disease (GVHD) is the primary complication of allogeneic, hemopoietic, stem cell transplantation (HSCT). Murine models suggest that gut toxicity, induced by the intensive chemotherapy preceding hematopoietic stem cell infusion, aggravates systemic GVHD. In HSCT patients gut toxicity correlates with chemotherapy intensity. The present study investigates acute GVHD severity and intestinal toxicity in patients undergoing allogeneic HSCT. In 38 patients intestinal permeability was assessed before and after chemotherapy (on days -1, +4, +7 and +14 as related to the stem cell infusion). Cumulative acute GVHD (days 0-100) and clinical intestinal toxicity (days 0-14) were evaluated in parallel. Patients with mild, acute GVHD (grades 0-I) had better-preserved intestinal barrier function (P=0.04) and less pronounced cumulative clinical intestinal toxicity (P=0.02) compared with patients with more severe acute GVHD (grades II-IV). Gut toxicity predicts acute GVHD severity. Therefore, gut protective strategies may diminish GVHD severity in allogeneic HSCT patients.

Biomarkers for radiation-induced small bowel epithelial damage: An emerging role for plasma Citrulline

Reduction of cancer treatment-induced mucosal injury has been recognized as an important target for improving the therapeutic ratio as well as reducing the economic burden associated with these treatment related sequellae. Clinical studies addressing this issue are hampered by the fact that specific objective parameters, which enable monitoring of damage in routine clinical practice, are lacking. This review summarizes pros and cons of currently available endpoints for intestinal injury. The metabolic background and characteristics of plasma citrulline, a recently investigated biomarker specifically for small intestinal injury, are discussed in more detail.

Intestinal paracellular permeability is not affected in chronic congestive heart failure

BACKGROUND

In chronic heart failure (CHF) it has been proposed that a dysfunction of the gastrointestinal barrier could lead to translocation of endotoxin into the systemic circulation. A secondary inflammatory reaction, observed as increased levels of cytokines, could negatively affect cardiac function. The aims of this paper were therefore to determine whether patients with CHF have a disturbed mucosal barrier and whether it was possible to detect endotoxin in venous blood.

METHODS

Nineteen stable patients with CHF (New York Heart Association II-III, EF<or=40% or EF>40% and earlier hospitalisation for heart failure) were investigated. Twenty healthy subjects (HS group) and 25 patients, who were admitted for bone marrow transplantation (BMT group), served as controls. Gastrointestinal permeability was assessed by a (51)Cr-EDTA absorption test.

RESULTS

Eleven patients with and eight without peripheral oedema were included. Median age was 76.5 years. Intestinal permeability was 1.82+/-1.96% in the CHF patients and 1.54+/-.59% and 1.9+/-.9% in HS and BMT groups, respectively (p=0.4 and p=0.7, CHF vs HS and BMT, respectively). No difference was found between patients with and without oedema and endotoxins were below the detection limit in all patients.

DISCUSSION

This study does not support the hypothesis that patients with CHF have a dysfunctional gastrointestinal barrier, at least as assessed by the (51)Cr-EDTA resorbtion test.

Intestinal mucosal dysfunction and infection during remission-induction therapy for acute myeloid leukaemia

Intestinal barrier function was prospectively examined in the course of a clinical trial evaluating the efficacy and safety of lisofylline for reducing cytotoxic therapy-induced intestinal epithelial damage-related infectious morbidity in patients receiving standard remission-induction therapy for acute myeloid leukaemia. The absorption and permeation of oral D-Xylose, lactulose and mannitol were measured weekly from baseline until marrow recovery in adult recipients of idarubicin plus cytarabine for untreated acute myeloid leukaemia. These studies were correlated with non-haematologic chemotherapy-related toxicities reflecting mucosal damage, including nausea, vomiting, stomatitis, diarrhoea, abdominal pain and systemic infection. D-xylose absorption decreased and lactulose:mannitol ratio reflecting intestinal permeability increased from baseline until the second and third week after the beginning of the treatment followed by recovery. These measures correlated with infection rates, nausea, vomiting, diarrhoea and increased blood product utilization. Lisofylline was associated with increased intestinal permeability, nausea, vomiting and infection-related morbidity despite a reduction in the duration of neutropaenia. These surrogates of intestinal barrier function correlated well with clinically important outcomes despite the failure to demonstrate reduced morbidity with lisofylline and represent useful objective outcome measurements for future clinical trials of products for the amelioration of the effects of cytotoxic therapy on the intestinal mucosa.

Early bacteremia in pediatric hematopoietic stem cell transplant patients on oral antibiotic prophylaxis

BACKGROUND

Bacteremia occurs during hematopoietic stem cell transplant (HSCT) in 20%-25% of patients and the use of gut decontamination (GD) to decrease this risk is controversial. Our purpose was to determine the incidence of bacteremia and antimicrobial resistance post-HSCT in pediatric patients receiving GD, and to identify risk factors associated with infection.

PROCEDURES

This was a retrospective cohort study of 182 pediatric patients undergoing first HSCT for malignant disease at The Children's Hospital of Philadelphia from January, 1999 to December, 2002. We examined the impact of age, sex, race, diagnosis, disease status, conditioning regimen, recent bacteremia, stem cell source, donor, graft versus host disease prophylaxis agents, and mucositis severity using Cox proportional hazard models. GD consisted of amoxicillin (azithromycin, if penicillin allergic) and oral gentamicin. Outcome was first episode of bacteremia prior to absolute neutrophil count (ANC) 500/mm(3). Antibiotic susceptibilities were performed on all isolates.

RESULTS

Seventy-four patients (41%) developed bacteremia. The majority were Gram-positive cocci, with Staphylococcal (50%) and Streptococcal species (28%) the most common. Gram-negative organisms were identified in 22% with Pseudomonas (5.7%) and Klebsiella species (3.4%) the most common. Of the Streptococcal infections, 72% were resistant to ampicillin; only 25% of the Gram-negative bacteria were resistant to gentamicin. Race was the only factor associated with early bacteremia (hazard ratio 2.3 for non-Caucasian, non-African-American patients, CI 1.3-4.3, P = 0.007).

CONCLUSIONS

Early bacteremia is common after HSCT, despite the use of GD. Resistant Gram-positive organisms predominate, consistent with recent trends in immunocompromised patients. Although used in practice, there is no clear evidence for the efficacy of GD and this study provides the basis upon which to develop a randomized clinical trial evaluating the current GD regimen with placebo.

Intestinal permeability and systemic infections in critically ill patients: effect of glutamine

OBJECTIVE

This article provides a critical review of the evidence indicating that an increase in intestinal permeability is associated with the installation of bacteremia, sepsis, and the multiple organ failure syndrome and that glutamine in pharmacologic doses reduces the acute increase of intestinal permeability and the infection frequency in critically ill patients.

DATA SOURCE

All studies published until December 2004 about intestinal permeability, bacterial translocation, and glutamine were located by search of PubMed and Web of Science. The reference lists of review articles and primary publications were also examined to identify references not detected in the computer search.

STUDY SELECTION

Clinical and experimental studies investigating the correlation between intestinal permeability, bacterial translocation, and frequency of infections, associated or not with the effect of glutamine administration.

DATA EXTRACTION

Information regarding patient population, experimental design, glutamine doses and routes of administration, nutritional therapy prescribed, methods used to assess intestinal permeability, metabolic variables, and the frequency of infections were obtained from the primary literature.

DATA SYNTHESIS

Intestinal permeability is increased in critically ill patients. The results have not always been consistent, but the studies whose results support the association between intestinal permeability and systemic infections have had better design and more appropriate controls. The administration of glutamine by the intravenous or oral route and at the doses recommended before or immediately after surgery, burns, or the administration of parenteral nutrition has a protective effect that prevents or reduces the intensity of the increase in intestinal permeability. Glutamine reduces the frequency of systemic infections and may also reduce the translocation of intestinal bacteria and toxins, but this has not been demonstrated.

CONCLUSIONS

Glutamine administration improves the prognosis of critically ill patients presumably by maintaining the physiologic intestinal barrier and by reducing the frequency of infections.

Monitoring myeloablative therapy-induced small bowel toxicity by serum citrulline concentration: a comparison with sugar permeability tests

BACKGROUND

Intestinal mucositis is an important cause of cancer treatment-related morbidity and mortality, carrying a serious economic burden. Currently, objective parameters are lacking that would enable the monitoring of gut damage in routine clinical practice, thus hindering the development of clinical studies designed to investigate potential new strategies aimed at reducing or preventing this side effect. The authors investigated the characteristics of serum citrulline concentration compared with sugar permeability tests with respect to its use as a marker for cancer treatment-induced small bowel injury.

METHODS

In this prospective study, 10 patients with hematologic malignancies who were receiving myeloablative therapy had gut toxicity assessed with sugar permeability tests. Serum citrulline concentrations also were determined using archival serum samples. The association between both parameters and their respective characteristics were analyzed and compared with data from the literature.

RESULTS

Sensitivity and specificity were better for the citrulline assay compared with sugar permeability tests. Maximum gut damage assessed with the citrulline assay was observed 1-2 weeks earlier compared with the sugar permeability test. Similarly, citrulline indicated recovery of gut damage at 3 weeks after transplantation, whereas most sugar permeability tests remained abnormal.

CONCLUSIONS

The simplicity of the method, the low costs, and the lack of drawbacks to the method make the citrulline assay the first choice for measuring and monitoring treatment-related gut damage and provides an objective parameter for cancer treatment-related gut toxicity.

Measuring mucosal damage induced by cytotoxic therapy

We scored oral mucositis and gut toxicity and measured sugar permeability testing among 56 recipients of a haematopoietic stem cell transplant (HSCT) given myeloablative conditioning with idarubicin, cyclophosphamide and TBI, and a group of 18 patients given cytotoxic chemotherapy for newly diagnosed acute myeloid leukaemia (AML) or myelodysplastic syndrome (MDS). Gut integrity was already disturbed in the AML/MDS group as measured by the lactulose/rhamnose ratio (L/R ratio=0.09) before therapy and was severely perturbed (L/R ratio >0.13) for a month after HSCT. Oral mucositis and to a lesser extent gut toxicity was only significantly correlated with disturbed permeability in the transplant group. The data suggest that sugar permeability, oral mucositis and gut toxicity measure different features of mucosal damage after intensive cytotoxic therapy.

Gastric emptying after autologous haemopoietic stem-cell transplantation: a prospective trial

Gastroparesis may be involved in the pathophysiology of prolonged nausea and vomiting after haemopoietic stem-cell transplantation (HSCT), but this has not been prospectively investigated. Gastric emptying (GE) was investigated in 20 patients before and 2 months after autologous HSCT. Gastrointestinal symptoms were graded prospectively and oral energy intake was recorded in parallel. Before transplant, all patients were asymptomatic and GE was within the reference range. Post transplant GE was delayed in three patients and three patients reported nausea and/or vomiting. Neither gastrointestinal symptoms nor oral energy intake post transplant discriminated between patients with or without delayed GE. Oral energy intake before transplant was lower (P=0.05), and there was a greater need for total parenteral nutrition (TPN) among patients who developed gastroparesis post transplant (P<0.05). Delayed GE after HSCT was found to be less common than had been believed from retrospective studies. Gastroparesis may be involved in some cases of prolonged nausea and vomiting after autologous HSCT but alternative explanations should be considered. Symptoms consistent with gastroparesis did not correlate with GE. Patients at risk of developing gastroparesis may be found among those with nutritional difficulties before and during the transplant course.

Infections in Patients with Hematological Cancer: Recent Developments

One of the most common complications involved in treating patients with hematologic cancer is infection. In many cases there are multiple factors that predispose these patients to infections such as neutropenia induced by therapy or bone marrow involvement, hypogammaglobulinemia, T-cell dysfunction, and mucosal damage. In addition, newer therapies have changed the spectrum of infection that is seen in these patients.

In Section I, Dr. Blijlevens discusses mucosal damage as a major risk factor for complications of cytotoxic chemotherapy. She focuses on mucosal barrier injury (MBI) as manifest in the GI tract and will describe a pathological model to explain MBI, evaluate risk factors for development of this syndrome, explain the relationship between MBI and infection, and discuss treatment and prevention of this injury.

Invasive fungal infections continue to represent a significant problem in patients with hematologic cancer. In Section II, Drs. Anaissie and Mahfouz review the latest developments in the diagnosis, prevention, and management of invasive fungal infections with a focus on a risk-adjusted approach to this problem.

Finally, in Section III, Dr. O’Brien reviews infections associated with newer therapeutic regimens in hematologic cancers. The spectrum of infections has changed with the use of purine analogs and the advent of monoclonal antibodies. The profound T-cell suppression associated with these therapies has led to the emergence of previously rare infections such as cytomegalovirus. An approach to both prophylaxis and management of these infections is discussed.

Pharmacokinetics of acyclovir in immunocompromized children with leukopenia and mucositis after chemotherapy: can intravenous acyclovir be substituted by oral valacyclovir?

BACKGROUND

The efficacy of oral acyclovir, a purine nucleoside analogue with activity against human herpes viruses, is limited as a result of its low bioavailability. Valacyclovir, the L-valyl ester of acyclovir, has been developed as a pro-drug to improve the bioavailability. The aim of the present study was to compare the pharmacokinetics of acyclovir after intravenous administration and after oral administration of valacyclovir.

PROCEDURE

The pharmacokinetics of acyclovir were studied in 18 children aged 1.4-18.1 years (median: 6.9 years; 9 females) after intravenous infusion (1 hr; median dose: 10.5 mg/kg). In 10 of the children the pharmacokinetics of acyclovir were also studied after oral administration of valacyclovir (median dose: 34.1 mg/kg). Quantification of acyclovir in serum was performed by reversed-phase liquid chromatography with fluorometric detection. The pharmacokinetic analysis was performed by pharmacokinetic modelling.

RESULTS

The serum concentration versus time curves of acyclovir were described by the two compartment model after intravenous administration and by the one compartment model with a zero- or first-order absorption phase after oral administration of valacyclovir. The bioavailability of acyclovir after oral administration of valacyclovir was 45% (median value; 95% CI: 37-55%).

CONCLUSION

It is possible to substitute intravenous acyclovir therapy by oral valacyclovir therapy in children with leukopenia and mucositis after chemotherapy. This finding can at present not be fully implemented in clinical practice, since a commercial pharmaceutical formulation of valacyclovir aimed for children not able to swallow intact tablets is lacking. Crushed valacyclovir tablets have a very unpleasant taste, but can be administered to children through nasogastric tubes.

The gut mucosa barrier is preserved during allogeneic, haemopoietic stem cell transplantation with reduced intensity conditioning

The efficacy of allogeneic, haemopoietic stem cell transplantation (HSCT) is limited by concomitant toxicity. This has led to the development of less toxic, reduced intensity conditioning (RIC) protocols, whose therapeutic benefit is largely related to an associated, immunity-mediated graft-versus-malignancy effect rather than by the cytotoxic treatment itself. Murine HSCT models suggests that acute graft-versus-host disease (GVHD) increases with the intensification of the conditioning regimen mediated by loss of integrity of the gut mucosa barrier. The present study was undertaken to investigate gastro-intestinal (GI) permeability during allogeneic HSCT with RIC. In 17 patients (myeloablative conditioning in nine, RIC in eight), intestinal permeability was assessed by a (51)Cr-EDTA absorption test before the start of cytotoxic treatment the day before stem cell infusion (day -1) and 4, 7 and 14 days after stem cell infusion. Patients receiving RIC did not develop any significant increase in intestinal permeability during the transplantation course but in myeloablatively conditioned patients there was a significant increase in intestinal permeability the day before the stem cell infusion (P < 0.005), on day 4 (P < 0.005), on day 7 (P < 0.01) and on day 14 (P < 0.005) after stem cell infusion, compared with the baseline. Myeloablative conditioning also revealed increased intestinal permeability on day 7 compared with the RIC (P < 0.05). The finding of preserved intestinal-barrier function during allogeneic HSCT with RIC is discussed, with reference to the hypothesis that GI tract damage may be an important initiating event of GVHD.

Nutrient support in hematopoietic cell transplantation

High-dose cytoreduction and hematopoietic stem cell infusion form the basis for treatment of hematologic cancers, defects or failure of hematopoiesis, and some solid tumors. As an antitumor therapy, allogeneic hematopoietic cell transplantation (HCT) is superior to autologous HCT by induction of a graft-vs-tumor effect. However, recipients of allografts suffer higher transplant-related mortality owing to graft-vs-host disease (GVHD). Nutrition support research must recognize that HCT is a heterogeneous modality whose short and long-term outcomes are affected by transplant type, preparative regimens, diagnosis, disease stage, age, and nutritional status. The field of HCT will diversify further as lower dose cytoreduction and mixed chimerism grafts allow expansion of the technique to older patients and to other diseases.

Mucosal barrier injury: biology, pathology, clinical counterparts and consequences of intensive treatment for haematological malignancy: an overview

Mucositis is an inevitable side-effect of the conditioning regimens used for haematopoietic stem cell transplantation. The condition is better referred to as mucosal barrier injury (MBI) since it is primarily the result of toxicity and is a complex and dynamic pathobiological process manifested not only in the mouth but also throughout the entire digestive tract. A model has been proposed for oral MBI and consists of four phases, namely inflammatory, epithelial, ulcerative and healing phases. A variety of factors are involved in causing and modulating MBI including the nature of the conditioning regimen, the elaboration of pro-inflammatory and other cytokines, translocation of the resident microflora and their products, for example, endotoxins across the mucosal barrier, exposure to antimicrobial agents and whether or not the haematopoietic stem cell graft is from a donor. Neutropenic typhlitis is the most severe gastrointestinal manifestation of MBI, but it also influences the occurrence of other major transplant-related complications including acute GVHD, veno-occlusive disease and systemic infections. The pathobiology, clinical counterparts and the means of measuring MBI are discussed together with potential approaches for prevention, amelioration and, perhaps, even cure. Bone Marrow Transplantation (2000) 25, 1269-1278.

Bioavailability of aciclovir after oral administration of aciclovir and its prodrug valaciclovir to patients with leukopenia after chemotherapy

The median bioavailabilities of aciclovir after administration of aciclovir and its prodrug valaciclovir were 21.5 and 70.1%, respectively, in 12 patients with malignant hematological diseases with leukopenia after chemotherapy. The interindividual variations of the bioavailability were 48.5 and 21.0% after administration of aciclovir and valaciclovir, respectively. Neither the bioavailability nor the interindividual variation of area under the concentration-time curve of oral aciclovir or valaciclovir differed from that reported in healthy volunteers.