Alanyl-glutamine hastens morphologic recovery from 5-fluorouracil-induced mucositis in mice

Preparation of healing promotive alanyl-glutamine-poly(p-dioxanone) electrospun membrane integrated with gentamycin and its application for intestinal anastomosis in rats

Anastomosis surgery at the intestinal site is performed on millions of individuals every year. However, several persistent complications, such as anastomotic leakage, abnormal adhesion, and anastomotic stenosis, have been observed after the surgery. For promoting anastomotic healing and to overcome the challenges mentioned above, re-epithelialization at anastomotic sites is crucial. In this study, an epithelialization-promoting macromolecular prodrug Ala-Gln-PPDO was prepared and processed into fibrous membranes by electrospinning. Ala-Gln and gentamicin were sustainably released from the electrospun membranes with degradation of these membranes to promote the proliferation of rat intestinal epithelial cells and suppress the proliferation of Staphylococcus aureus and Escherichia coli. The comprehensive repair effects of Ala-Gln-PPDO membranes have been evaluated in rat models of intestinal anastomosis in this study. Application of Ala-Gln-PPDO membranes, especially the gentamicin-incorporated Ala-Gln-PPDO ones, could prevent adhesion between the injured intestine and surrounding intestinal tissues. In addition, they did not affect the healing strength of anastomotic stoma negatively and could promote re-epithelialization at the anastomotic sites. Furthermore, the gentamicin-incorporated Ala-Gln-PPDO membranes could relieve stenosis at anastomotic sites. The gentamicin-incorporated Ala-Gln-PPDO electrospun membrane is a promising, comprehensive implantable material for promoting healing after gastrointestinal anastomosis owing to its effects involving the promotion of re-epithelialization, prevention of adhesion, and relieving of anastomotic stenosis.

Elemental diet directly affects chemotherapy-induced dermatitis and raw wound areas

Elental^® is an L-glutamine-rich elemental diet (ED) that has been widely used in Japan as a nutritional supplement for malnourished patients. In addition, Elental^® has been successfully used in the management of chemotherapy-induced mucositis in cancer patients. Recently, it was also reported that Elental^® can effectively reduce chemotherapy-induced oral mucositis in patients with oral squamous cell carcinoma, and can also reduce mucositis and dermatitis in animal models. However, it is unclear whether oral intake or topical application of Elental^® can act directly on chemotherapy-induced oral mucositis or dermatitis. The aim of the present study was to investigate the possible direct healing effect of Elental^® on chemotherapy-induced dermatitis and raw wound areas in a mouse model. Dermatitis and raw wounds were induced in nude mice by administration of 5-fluorouracil (5-FU) (via gastric tube) and mechanical injury (using a metal brush or a surgical knife). We then compared the outcome following oral or topical application of Elental^® in these mice. The effect of Elental^® on the growth and migration ability of the human oral keratinocyte cell line, HOK, was also examined using MTT and migration assays, respectively. In the mouse model, both oral administration and topical application of Elental^® reduced 5-FU-induced dermatitis and healed raw wound areas more effectively compared with the topical application of saline. The MTT assay revealed that Elental^® exerted a growth-promoting effect on HOKs. In addition, Elental^® enhanced the ability of HOKs to migrate, as demonstrated by the migration assay. These findings demonstrated that the topical application as well as the oral intake of Elental^® exerted a direct healing effect on chemotherapy-induced dermatitis or raw wound areas. The data also indicated that oral intake of an ED may exert a direct healing effect on chemotherapy-induced oral mucositis.

Combination Compositions Composed of l-Glutamine and Si-Jun-Zi-Tang Might Be a Preferable Choice for 5-Fluorouracil-Induced Intestinal Mucositis: An Exploration in a Mouse Model

Intestinal mucositis is a common toxicity of many anti-neoplastic therapies that negatively influences health, the quality of life, economic outcomes, and even the success of cancer treatment. Unfortunately, there is presently no optimal medicine that is able to effectively manage this condition. l-glutamine is one of the most frequently used agent in practice among the limited treatment choices due to its safety and inexpensiveness despite there being a lack of evidence. Previous studies indicated that l-glutamine may alleviate mucositis and mucosal atrophy but failed to improve patients' macroscopic conditions, such as the occurrence of diarrhea. A compound glutamine capsule (G-SJZ), composed of l-glutamine and the traditional Chinese herbal formula Si-Jun-Zi-Tang, has been used in China for 23 years to treat many types of gastrointestinal diseases, including gastrointestinal reactions induced by radiotherapy and chemotherapy. However, the exact effect of G-SJZ on intestinal mucositis is unclear, and moreover, whether l-glutamine combined with Si-Jun-Zi-Tang is more effective than l-glutamine alone have not been studied. In the current study, we explored the effects of G-SJZ and l-glutamine in a mouse model of intestinal mucositis induced by 5-fluorouracil (5-Fu). The results revealed that pretreatment with G-SJZ ameliorated the physical manifestations of weight loss and the severity of diarrhea following continuous 5-Fu injections in mice. Likewise, the histopathological damage and the destruction of villus and crypt structures in the intestinal mucosa as well as the increase in circulating intestinal injury markers caused by 5-Fu were reversed with G-SJZ pretreatment. Furthermore, the protective effect of G-SJZ was accompanied by modulations in the immunohistochemical expression of tight junction proteins. Interestingly, although treatment with a dose of l-glutamine alone that was equivalent to the dose in G-SJZ also showed a protective effect, it did not appear to be as strong as treatment with G-SJZ. Si-Jun-Zi-Tang in G-SJZ may compensate for the deficiencies of l-glutamine in this model which seems not to be related to the regulation of tight junction proteins. Our study is the first to suggest that the combined use of l-glutamine and Si-Jun-Zi-Tang might be more effective than l-glutamine alone despite exact mechanism still needs further study. Because of the limited number of therapeutic agents, G-SJZ is likely to be a preferable choice for intestinal mucositis.

Protective effect of β-D-glucan and glutamine on the genomic instability induced by Cytarabine/Ara-C in BALB/c mice

Prophylactic antibiotics and growth promoters have been substituted, mainly for livestock, by immunomodulators and intestinal health promoters - such as β-D-glucans and glutamine. The aim of this study was to verify the beneficial effects of β-D-glucans and glutamine against Cytarabine/Ara-C, evaluating the DNA damage in leukocytes, the leukogram, and the mitotic index of intestinal crypts cells. Balb/C mice received treatment with β-D-glucan (80 mg/Kg), glutamine (150 mg/Kg), or both, for 21 days. On the last two days of this period, Ara-C was administered (1.8 mg/animal) by intraperitoneal injection every 12 h. The animals submitted to the treatment with Ara-C presented the highest genotoxic index, a significant leukopenia, and a decrease in the mitotic index of the intestinal crypts cells. Treatment with β-D-glucan protected the leukocytes against DNA fragmentation induced by Ara-C. Glutamine alone promoted maintenance of the mitotic index and, in association with β-Dglucan, reduced leukopenia. Thus, the use of β-D-glucan and glutamine proved to be beneficial to intestinal tropism. This can happen once the damage to the genetic material, prevented by the treatments with β-D-glucan and glutamine, can result in genotoxicity. Not only this, but it might be capable of turning into a mutagenesis, with consequential physiopathological alterations.

Elemental Diet Accelerates the Recovery From Oral Mucositis and Dermatitis Induced by 5-Fluorouracil Through the Induction of Fibroblast Growth Factor 2

Mucositis and dermatitis induced by anticancer agents are common complications of anticancer therapies. In this study, we evaluated the efficacy of Elental (Ajinomoto Pharmaceutical Ltd, Tokyo, Japan), an elemental diet with glutamine in the treatment of 5-fluorouracil (5-FU)-induced oral mucositis and dermatitis in vivo and tried to clarify the underlying mechanisms of its action. Oral mucositis and dermatitis was induced through a combination of 5-FU treatment and mild abrasion of the cheek pouch in hamsters and the dorsal skin in nude mice respectively. These animals received saline, dextrin or Elental suspension (18 kcal/100 g) by a gastric tube daily until sacrifice. Elental reduced oral mucositis and dermatitis more effectively than dextrin in the animal model. Moreover, growth facilitating effects of Elental on HaCaT cells were examined in vitro. MTT assay, wound healing assay, and migration assay revealed that Elental could enhance the growth, invasion, and migration ability of HaCaT. ELISA and Western blotting showed upregulated FGF2 in Elental-treated HaCaT. These findings suggest that Elental is effective for the treatment of mucositis and dermatitis, and may accelerate mucosal and skin recovery through FGF2 induction and reepithelization.

Protective effect and potential mechanisms of Wei-Chang-An pill on high-dose 5-fluorouracil-induced intestinal mucositis in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Wei-Chang-An pill (WCA pill), a traditional Chinese pharmaceutical preparation, possessed potential anti-inflammatory advantages and noteworthy gastrointestinal regulations in digestive diseases, which might represent a promising candidate for the treatment of intestinal mucositis (IM) induced by 5-fluorouracil (5-FU).

AIM OF THE STUDY

To analyze the bioactive constituents and investigate the effect of methanol extraction from WCA pill (WCA ext) on 5-FU induced IM with underlying mechanisms.

MATERIALS AND METHODS

The analysis of serum bioactive constituents after WCA ext administration in rats was carried out by UHPLC-Quadrupole-Time of Flight-Mass Spectrometry. In mice, IM was induced by 5-FU and physical manifestations were measured during the period of drug delivery. Half of mice were assessed with histology, expression of inflammatory cytokines in ileum and plasma via hematoxylin and eosin staining, immunohistochemical staining as well as cytokine enzyme-linked immunosorbent assay test, respectively. Besides, gastric emptying (GE) and gastrointestinal transit (GIT) were further tested in the other half of 5-FU induced mice.

RESULTS

Twenty-two compounds were identified or tentatively characterized. IM induced by 5-FU was improved significantly after treatment with WCA ext through reducing the body weight loss, relieving the severe diarrhea, and inhibiting the GE as well as GIT. Further assessments validated that WCA ext promoted the recovery of intestinal mucosa, evaluated the activity of enterocyte proliferation, maintained the integrity of tight junction, and ameliorated the inflammatory disturbances.

CONCLUSIONS

These results suggested that WCA ext promoted the restoration of intestinal function in 5-FU-induced IM via regulating multiple sites of actions in intestinal homeostasis. Accordingly, WCA pill might be a promising therapeutic candidate for the prevention of IM during cancer chemotherapy.

Effects of alanyl-glutamine supplementation on the small intestinal mucosa barrier in weaned piglets

OBJECTIVE

The study was to investigate the effects of alanyl-glutamine (Ala-Gln) and glutamine (Gln) supplementation on the intestinal mucosa barrier in piglets.

METHODS

A total of 180 barrows with initial weight 10.01±0.03 kg were randomly allocated to three treatments, and each treatment consisted of three pens and twenty pigs per pen. The piglets of three groups were fed with control diet [0.62% alanine (Ala)], Ala-Gln diet (0.5% Ala-Gln), Gln diet (0.34% Gln and 0.21% Ala), respectively.

RESULTS

The results showed that in comparison with control diet, dietary Ala-Gln supplementation increased the height of villi in duodenum and jejunum (p<0.05), Gln supplementation increased the villi height of jejunum (p<0.05), Ala-Gln supplementation up-regulated the mRNA expressions of epidermal growth factor receptor and insulin-like growth factor 1 receptor in jejunal mucosa (p<0.05), raised the mRNA expressions of Claudin-1, Occludin, zonula occludens protein-1 (ZO-1) and the protein levels of Occludin, ZO-1 in jejunal mucosa (p<0.05), Ala-Gln supplementation enlarged the number of goblet cells in duodenal and ileal epithelium (p<0.05), Gln increased the number of goblet cells in duodenal epithelium (p<0.05) and Ala-Gln supplementation improved the concentrations of secretory immunoglobulin A and immunoglobulin G in the jejunal mucosa (p<0.05).

CONCLUSION

These results demonstrated that dietary Ala-Gln supplementation could maintain the integrity of small intestine and promote the functions of intestinal mucosa barriers in piglets.

Glutamine in Alleviation of Radiation-Induced Severe Oral Mucositis: A Meta-Analysis

The aim of this meta-analysis was to assess the effectiveness of glutamine to treat severe mucositis induced by radiation therapy in patients with head and neck cancer. We undertook electronic searches of PubMed (1990 to January 2015), Embase (1990 to January 2015), and the Cochrane Library (2013, Issue 2) to identify relevant studies. We included randomized controlled trials of glutamine to alleviate oral mucositis (OM) in patients with head and neck cancer who received radiotherapy. Information regarding methods, patients, results, and risk of bias was independently extracted by two authors. Statistical analyses were conducted to calculate the odds ratio and 95% confidence intervals (95%CIs) using fixed-effect models. We identified five clinical studies that included 234 patients with head and neck cancer. All studies were assessed as being at low risk of bias in most items of six domains. In this meta-analysis, glutamine treatment showed a statistically significant benefit with respect to reducing the risk and severity of OM induced by radiotherapy compared to either placebo or no treatment (risk ratio 0.17, 95%CI 0.06-0.47). Overall, glutamine significantly reduces the risk and severity of OM during radiotherapy or chemotherapy. Further prospective and large trials are required to support the findings.

Dark Agouti rat model of chemotherapy-induced mucositis: establishment and current state of the art

Mucositis is a major oncological problem. The entire gastrointestinal and genitourinary tract and also other mucosal surfaces can be affected in recipients of radiotherapy, and/or chemotherapy. Major progress has been made in recent years in understanding the mechanisms of oral and small intestinal mucositis, which appears to be more prominent than colonic damage. This progress is largely due to the development of representative laboratory animal models of mucositis. This review focuses on the development and establishment of the Dark Agouti rat mammary adenocarcinoma model by the Mucositis Research Group of the University of Adelaide over the past 20 years to characterize the mechanisms underlying methotrexate-, 5-fluorouracil-, and irinotecan-induced mucositis. It also aims to summarize the results from studies using different animal model systems to identify new molecular and cellular markers of mucositis.

Alanyl-glutamine attenuates 5-fluorouracil-induced intestinal mucositis in apolipoprotein E-deficient mice

Apolipoprotein E (APOE=gene, apoE=protein) is a known factor regulating the inflammatory response that may have regenerative effects during tissue recovery from injury. We investigated whether apoE deficiency reduces the healing effect of alanyl-glutamine (Ala-Gln) treatment, a recognized gut-trophic nutrient, during tissue recovery after 5-FU-induced intestinal mucositis. APOE-knockout (APOE-/-) and wild-type (APOE+/+) C57BL6J male and female mice (N=86) were given either Ala-Gln (100 mM) or phosphate buffered saline (PBS) by gavage 3 days before and 5 days after a 5-fluorouracil (5-FU) challenge (450 mg/kg, via intraperitoneal injection). Mouse body weight was monitored daily. The 5-FU cytotoxic effect was evaluated by leukometry. Intestinal villus height, villus/crypt ratio, and villin expression were monitored to assess recovery of the intestinal absorptive surface area. Crypt length, mitotic, apoptotic, and necrotic crypt indexes, and quantitative real-time PCR for insulin-like growth factor-1 (IGF-1) and B-cell lymphoma 2 (Bcl-2) intestinal mRNA transcripts were used to evaluate intestinal epithelial cell turnover. 5-FU challenge caused significant weight loss and leukopenia (P<0.001) in both mouse strains, which was not improved by Ala-Gln. Villus blunting, crypt hyperplasia, and reduced villus/crypt ratio (P<0.05) were found in all 5-FU-challenged mice but not in PBS controls. Ala-Gln improved villus/crypt ratio, crypt length and mitotic index in all challenged mice, compared with PBS controls. Ala-Gln improved villus height only in APOE-/- mice. Crypt cell apoptosis and necrotic scores were increased in all mice challenged by 5-FU, compared with untreated controls. Those scores were significantly lower in Ala-Gln-treated APOE+/+ mice than in controls. Bcl-2 and IGF-1 mRNA transcripts were reduced only in the APOE-/- -challenged mice. Altogether our findings suggest APOE-independent Ala-Gln regenerative effects after 5-FU challenge.

Regulatory role of Lactobacillus acidophilus on inflammation and gastric dysmotility in intestinal mucositis induced by 5-fluorouracil in mice

PURPOSE

Lactobacillus acidophilus is widely used for gastrointestinal disorders, but its role in inflammatory conditions like in chemotherapy-induced mucositis is unclear. Here, we report the effect of L. acidophilus on 5-fluorouracil-induced (5-FU) intestinal mucositis in mice.

METHODS

Mice weighing 25-30 g (n = 8) were separated into three groups, saline, 5-FU, and 5-FU + L. acidophilus (5-FU-La) (16 × 10(9) CFU/kg). In the 5-FU-La group, L. acidophilus was administered concomitantly with 5-FU on the first day and alone for two additional days. Three days after the last administration of L. acidophilus, the animals were euthanized and the jejunum and ileum were removed for histopathological assessment and for evaluation of levels of myeloperoxidase activity, sulfhydryl groups, nitrite, and cytokines (TNF-α, IL-1β, CXCL-1, and IL-10). In addition, we investigated gastric emptying using spectrophotometry after feeding a 1.5-ml test meal by gavage and euthanasia. Data were submitted to ANOVA and Bonferroni's test, with the level of significance at p < 0.05.

RESULTS

Intestinal mucositis induced by 5-FU significantly (p < 0.05) reduced the villus height-crypt depth ratio and GSH concentration and increased myeloperoxidase activity and the nitrite concentrations compared with the control group. Furthermore, 5-FU significantly (p < 0.05) increased cytokine (TNF-α, IL-1β, and CXCL-1) concentrations and decreased IL-10 concentrations compared with the control group. 5-FU also significantly (p < 0.05) delayed gastric emptying and gastrointestinal transit compared with the control group. All of these changes were significantly (p < 0.05) reversed by treatment with L. acidophilus.

CONCLUSIONS

Lactobacillus acidophilus improves the inflammatory and functional aspects of intestinal mucositis induced by 5-FU.

Treatment withSaccharomyces boulardiireduces the inflammation and dysfunction of the gastrointestinal tract in 5-fluorouracil-induced intestinal mucositis in mice

Intestinal mucositis is an important toxic side effect of 5-fluorouracil (5-FU) treatment.Saccharomyces boulardiiis known to protect from intestinal injury via an effect on the gastrointestinal microbiota. The objective of the present study was to evaluate the effect ofS. boulardiion intestinal mucositis induced by 5-FU in a murine model. Mice were divided into saline, saline (control)+5-FU or 5-FU+S. boulardii(16 × 109colony-forming units/kg) treatment groups, and the jejunum and ileum were removed after killing of mice for the evaluation of histopathology, myeloperoxidase (MPO) activity, and non-protein sulfhydryl group (mainly reduced glutathione; GSH), nitrite and cytokine concentrations. To determine gastric emptying, phenol red was administered orally, mice were killed 20 min after administration, and the absorbance of samples collected from the mice was measured by spectrophotometry. Intestinal permeability was measured by the urinary excretion rate of lactulose and mannitol following oral administration.S. boulardiisignificantly reversed the histopathological changes in intestinal mucositis induced by 5-FU and reduced the inflammatory parameters: neutrophil infiltration (control 1·73 (sem0·37) ultrastructural MPO (UMPO)/mg, 5-FU 7·37 (sem1·77) UMPO/mg and 5-FU+S. boulardii4·15 (sem0·73) UMPO/mg); nitrite concentration (control 37·00 (sem2·39) μm, 5-FU 59·04 (sem11·41) μmand 5-FU+S. boulardii37·90 (sem5·78) μm); GSH concentration (control 477·60 (sem25·25) μg/mg, 5-FU 270·90 (sem38·50) μg/mg and 5-FU+S. boulardii514·00 (sem38·64) μg/mg). Treatment with S.Boulardiisignificantly reduced the concentrations of TNF-α and IL-1β by 48·92 and 32·21 % in the jejunum and 38·92 and 61·79 % in the ileum. In addition,S. boulardiidecreased the concentrations of chemokine (C–X–C motif) ligand 1 by 5-fold in the jejunum and 3-fold in the ileum. Interestingly,S. boulardiireduced the delay in gastric emptying (control 25·21 (sem2·55) %, 5-FU 54·91 (sem3·43) % and 5-FU+S. boulardii31·38 (sem2·80) %) and induced the recovery of intestinal permeability (lactulose:mannitol ratio: control 0·52 (sem0·03), 5-FU 1·38 (sem0·24) and 5-FU+S. boulardii0·62 (sem0·03)). In conclusion,S. boulardiireduces the inflammation and dysfunction of the gastrointestinal tract in intestinal mucositis induced by 5-FU.

Zinc, vitamin A, and glutamine supplementation in Brazilian shantytown children at risk for diarrhea results in sex-specific improvements in verbal learning

OBJECTIVE

To identify the impact of supplemental zinc, vitamin A, and glutamine, alone or in combination, on long-term cognitive outcomes among Brazilian shantytown children with low median height-for-age z-scores.

METHODS

A randomized, double-blind, placebo-controlled trial was conducted in children aged three months to nine years old from the urban shanty compound community of Fortaleza, Brazil. Demographic and anthropometric information was assessed. The random treatment groups available for cognitive testing (total of 167 children) were: (1) placebo, n = 25; (2) glutamine, n = 23; (3) zinc, n = 18; (4) vitamin A, n = 19; (5) glutamine+zinc, n = 20; (6) glutamine+vitamin A, n = 21; (7) zinc+vitamin A, n = 23; and (8) glutamine+zinc+vitamin A, n = 18. Neuropsychological tests were administered for the cognitive domains of non-verbal intelligence and abstraction, psychomotor speed, verbal memory and recall ability, and semantic and phonetic verbal fluency. Statistical analyses were performed using SPSS, version 16.0. ClinicalTrials.gov: NCT00133406.

RESULTS

Girls receiving a combination of glutamine, zinc, and vitamin A had higher mean age-adjusted verbal learning scores than girls receiving only placebo (9.5 versus 6.4, p = 0.007) and girls receiving zinc+vitamin A (9.5 versus 6.5, p = 0.006). Similar group differences were not found between male study children.

CONCLUSIONS

The findings suggest that combination therapy offers a sex-specific advantage on tests of verbal learning, similar to that seen among female patients following traumatic brain injury.

Glutamine and alanyl-glutamine increase RhoA expression and reduce Clostridium difficile toxin-a-induced intestinal epithelial cell damage

Clostridium difficile is a major cause of antibiotic-associated colitis and is associated with significant morbidity and mortality. Glutamine (Gln) is a major fuel for the intestinal cell population. Alanyl-glutamine (Ala-Gln) is a dipeptide that is highly soluble and well tolerated. IEC-6 cells were used in the in vitro experiments. Cell morphology was evaluated by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Cell proliferation was assessed by WST-1 and Ki-67 and apoptosis was assessed by TUNEL. Cytoskeleton was evaluated by immunofluorescence for RhoA and F-actin. RhoA was quantified by immunoblotting. TcdA induced cell shrinkage as observed by AFM, SEM, and fluorescent microscopy. Additionally, collapse of the F-actin cytoskeleton was demonstrated by immunofluorescence. TcdA decreased cell volume and area and increased cell height by 79%, 66.2%, and 58.9%, respectively. Following TcdA treatment, Ala-Gln and Gln supplementation, significantly increased RhoA by 65.5% and 89.7%, respectively at 24 h. Ala-Gln supplementation increased cell proliferation by 137.5% at 24 h and decreased cell apoptosis by 61.4% at 24 h following TcdA treatment. In conclusion, TcdA altered intestinal cell morphology and cytoskeleton organization, decreased cell proliferation, and increased cell apoptosis. Ala-Gln and Gln supplementation reduced intestinal epithelial cell damage and increased RhoA expression.

Glutamine: A novel approach to chemotherapy-induced toxicity

Treatment of cancer is associated with short- and long-term side-effects. Cancer produces a state of glutamine deficiency, which is further aggravated by toxic effects of chemotherapeutic agents leading to increased tolerance of tumor to chemotherapy as well as reduced tolerance of normal tissues to the side-effects of chemotherapy. This article reviews the possible role of glutamine supplementation in reducing the serious adverse events in patients treated with anticancer drugs. The literature related to the possible role of glutamine in humans with cancer and the supportive evidence from animal studies was reviewed. Searches were made and the literature was retrieved using PUBMED, MEDLINE, COCHRANE LIBRARY, CENAHL and EMBASE, with a greater emphasis on the recent advances and clinical trials. Glutamine supplementation was found to protect against radiation-induced mucositis, anthracycline-induced cardiotoxicity and paclitaxel-related myalgias/arthralgias. Glutamine may prevent neurotoxicity of paclitaxel, cisplatin, oxaplatin bortezomib and lenolidamide, and is beneficial in the reduction of the dose-limiting gastrointestinal toxic effects of irinotecan and 5-FU-induced mucositis and stomatitis. Dietary glutamine reduces the severity of the immunosuppressive effect induced by methotrexate and improves the immune status of rats recovering from chemotherapy. In patients with acute myeloid leukemia requiring parenteral nutrition, glycyl-glutamine supplementation could hasten neutrophil recovery after intensive myelosuppressive chemotherapy. Current data supports the usefulness of glutamine supplementation in reducing complications of chemotherapy; however, paucity of clinical trials weakens the clear interpretation of these findings.

Protective effects of alanyl-glutamine supplementation against nelfinavir-induced epithelial impairment in IEC-6 cells and in mouse intestinal mucosa

PURPOSE

Human Immunodeficiency Virus (HIV) protease inhibitors (PI) remain a crucial component of highly active therapy (HAART) and recently have been demonstrated to have potent antitumor effect on a wide variety of tumor cell lines. However, discontinuation of therapy is an important issue, which may be related to various side-effects, especially diarrhea. The aim of this study was to evaluate the effects of nelfinavir (NFV), an HIV PI, and of alanyl-glutamine (AQ) supplementation, on intestinal cell migration, proliferation, apoptosis and necrosis, using IEC-6 cells and on intestinal crypt depth, villus length, villus area, mitotic index and apoptosis in Swiss mice.

METHODS

Migration was evaluated at 12 and 24 h after injury using a wound healing assay. Cellular proliferation was measured indirectly at 24 and 48 h using tetrazolium salt WST-1. Apoptosis and necrosis were measured by flow cytometry using the Annexin V assay. Intestinal morphometry and mitotic index in vivo were assessed following a seven-day treatment with 100 mg/kg of NFV, given orally. In vivo proliferation and apoptosis were evaluated by intestinal crypt mitotic index and immunohistochemistry, respectively.

RESULTS

In vitro, AQ supplementation enhanced IEC-6 cell migration and proliferation, following challenge with NFV. In vivo, AQ increased intestinal villus length, villus area, crypt depth and cell proliferation and cell migration, following treatment with NFV. AQ did not decrease cell death induced by NFV both in vivo and in vitro.

CONCLUSIONS

AQ supplementation is potentially beneficial in preventing the effects of PIs, such as NFV, in the intestinal tract.

Apolipoprotein E COG 133 mimetic peptide improves 5-fluorouracil-induced intestinal mucositis

Background

Intestinal mucositis is one of the major troublesome side effects of anticancer chemotherapy leading to poor patient compliance. In this study we addressed the role of the novel apolipoprotein E (ApoE) COG 133 mimetic peptide in 5-fluorouracil (5-FU)-challenged Swiss mice and IEC-6 cell monolayers. Experiments were also conducted in C57BL6J ApoE knock-out mice to assess the effects of apoE peptide treatment.

Methods

Experimental groups were as follows: unchallenged controls, 5-FU-challenged mice (450 mg/kg, i.p) with or without the ApoE peptide (0.3, 1, and 3 μM, given twice daily i.p. for 4 days). Mice were sacrificed 3 days after 5-FU challenge. Proximal small intestinal samples were harvested for molecular biology and histological processing. We conducted ELISA assays and RT-PCR to target IL-1β, TNF-α, IL-10, iNOS, and myeloperoxidase (MPO) to assess intestinal inflammation. Cell death and NF-κB assays were also conducted in apoE knock-out mice. In our in vitro models, IEC-6 cells were exposed to 1 mM of 5-FU in glutamine free media with or without the ApoE peptide (0.02, 0.2, 2, 5, 10, and 20 μM). We investigated IEC-6 cell proliferation and migration, 24 h after the 5-FU challenge. Additionally, apoptotic IEC-6 cells were measured by Tunel and flow cytometry. Equimolar doses of the ApoA-I (D4-F) peptide were also used in some experiments for comparative studies.

Results

Villus blunting and heavy inflammatory infiltrates were seen in the 5-FU-challenged group, findings that were partially ameliorated by the ApoE peptide. We found increased intestinal MPO and pro-inflammatory IL-1β and TNF-α levels, and TNF-α and iNOS transcripts, and reduction of IL-10 following 5-FU treatment, each of which were partially abrogated by the peptide. Improvements were also found in IEC-6 cell apoptosis and migration following ApoE and D-4F treatment.

Conclusion

Altogether, these findings suggest that the novel ApoE COG 133 mimetic peptide can reduce 5-FU-induced intestinal changes and potentially benefit mucositis.

Progress towards the development of animal models of chemotherapy-induced gastrointestinal mucositis

The pathogenesis of chemotherapy-induced gastrointestinal mucositis is not fully elucidated, which makes it extremely difficult to develop effective interventions. Recently, the use of animal models of chemotherapy-induced gastrointestinal mucositis has led to advances in the understanding of cellular mechanisms and clinical pharmacology of various types of chemotherapy drugs. Tumor-bearing models, non-tumor-bearing models, transgenic models and gene knockout models have been developed to assess the effect of chemotherapy on chemotherapy-induced gastrointestinal mucositis. In this paper, we comprehensively analyze the advantages and disadvantages of various methods for developing chemotherapy-induced gastrointestinal mucositis to provide a reference for the choice of animal models for future research of chemotherapy-associated mucosal toxicity and the underlying mechanisms.

Arginine decreases Cryptosporidium parvum infection in undernourished suckling mice involving nitric oxide synthase and arginase

OBJECTIVE

This study investigated the role of L-arginine supplementation to undernourished and Cryptosporidium parvum-infected suckling mice.

METHODS

The following regimens were initiated on the fourth day of life and injected subcutaneously daily. The C. parvum-infected controls received L-arginine (200 mmol/L) or phosphate buffered saline. The L-arginine-treated mice were grouped to receive NG-nitro-arginine methyl ester (L-NAME) (20 mmol/L) or phosphate buffered saline. The infected mice received orally 10(6) excysted C. parvum oocysts on day 6 and were euthanized on day 14 at the infection peak.

RESULTS

L-arginine improved weight gain compared with the untreated infected controls. L-NAME profoundly impaired body weight gain compared with all other groups. Cryptosporidiosis was associated with ileal crypt hyperplasia, villus blunting, and inflammation. L-arginine improved mucosal histology after the infection. L-NAME abrogated these arginine-induced improvements. The infected control mice showed an intense arginase expression, which was even greater with L-NAME. L-arginine decreased the parasite burden, an effect that was reversed by L-NAME. Cryptosporidium parvum infection increased urine NO(3)(-)/NO(2)(-) concentrations compared with the uninfected controls, which was increased by L-arginine supplementation, an effect that was also reversed by L-NAME.

CONCLUSION

These findings show a protective role of L-arginine during C. parvum infection in undernourished mice, with involvement of arginase I and nitric oxide synthase enzymatic actions.

Effects of adenosine A₂A receptor activation and alanyl-glutamine in Clostridium difficile toxin-induced ileitis in rabbits and cecitis in mice

Background

Severe Clostridium difficile toxin-induced enteritis is characterized by exuberant intestinal tissue inflammation, epithelial disruption and diarrhea. Adenosine, through its action on the adenosine A_2A receptor, prevents neutrophillic adhesion and oxidative burst and inhibits inflammatory cytokine production. Alanyl-glutamine enhances intestinal mucosal repair and decreases apoptosis of enterocytes. This study investigates the protection from enteritis by combination therapy with ATL 370, an adenosine A_2A receptor agonist, and alanyl-glutamine in a rabbit and murine intestinal loop models of C. difficile toxin A-induced epithelial injury.

Methods

Toxin A with or without alanyl-glutamine was administered intraluminally to rabbit ileal or murine cecal loops. Animals were also given either PBS or ATL 370 parenterally. Ileal tissues were examined for secretion, histopathology, apoptosis, Cxcl1/KC and IL-10.

Results

ATL 370 decreased ileal secretion and histopathologic changes in loops treated with Toxin A. These effects were reversed by the A_2A receptor antagonist, SCH 58261, in a dose-dependent manner. The combination of ATL 370 and alanyl-glutamine significantly further decreased ileal secretion, mucosal injury and apoptosis more than loops treated with either drug alone. ATL 370 and alanyl-glutamine also decreased intestinal tissue KC and IL-10.

Conclusions

Combination therapy with an adenosine A_2A receptor agonist and alanyl-glutamine is effective in reversing C. difficile toxin A-induced epithelial injury, inflammation, secretion and apoptosis in animals and has therapeutic potential for the management of C. difficile infection.

Alanyl-glutamine promotes intestinal epithelial cell homeostasis in vitro and in a murine model of weanling undernutrition

Alanyl-glutamine (Ala-Gln) has recently been shown to enhance catch-up growth and gut integrity in undernourished children from Northeast Brazil. We hypothesized that the intestinal epithelial effects of Ala-Gln in malnourished weanling mice and mouse small intestinal epithelial (MSIE) cells would include modulation of barrier function, proliferation, and apoptosis. Dams of 10-day-old suckling C57BL/6 pups were randomized to a standard diet or an isocaloric Northeast Brazil "regional basic diet," moderately deficient in protein, fat, and minerals. Upon weaning to their dam's diet on day of life 21, pups were randomized to Ala-Gln solution or water. At 6 wk of age, mice were killed, and jejunal tissue was collected for morphology, immunohistochemistry, and Ussing chamber analysis of transmucosal resistance and permeability. Proliferation of MSIE cells in the presence or absence of Ala-Gln was measured by MTS and bromodeoxyuridine assays. MSIE apoptosis was assessed by annexin and 7-amino-actinomycin D staining. Pups of regional basic diet-fed dams exhibited failure to thrive. Jejunal specimens from undernourished weanlings showed decreased villous height and crypt depth, decreased transmucosal resistance, increased permeability to FITC-dextran, increased claudin-3 expression, and decreased epithelial proliferation and increased epithelial apoptosis (as measured by bromodeoxyuridine and cleaved caspase-3 staining, respectively). Undernourished weanlings supplemented with Ala-Gln showed improvements in weight velocity, villous height, crypt depth, transmucosal resistance, and epithelial proliferation/apoptosis compared with unsupplemented controls. Similarly, Ala-Gln increased proliferation and reduced apoptosis in MSIE cells. In summary, Ala-Gln promotes intestinal epithelial homeostasis in a mouse model of malnutrition-associated enteropathy, mimicking key features of the human disease.

CXCL9 attenuated chemotherapy-induced intestinal mucositis by inhibiting proliferation and reducing apoptosis

Mucositis arising from cancer chemotherapy is a common problem for which there is no definitive treatment. 5-fluorouracil (5-FU) is a common cytotoxic agent used to treat solid tumors. A global gene expression array was performed to identify genetic signals involved in the pathogenesis of mucositis. The chemokine (C-X-C motif) ligand 9 (CXCL9) was one of the candidates identified that presented a characteristic gene expression profile; its temporal expression pattern was correlated with the damage and regeneration phases of the small intestine upon 5-FU chemotherapy. We found that prophylactic CXCL9 administration was able to attenuate the severity of mucositis, weight loss and diarrhea caused by chemotherapy. CXCL9 also increased the tolerance of the mice to lethal-dose chemotherapy. Moreover, we demonstrated that CXCL9 was able to promote the proliferation and regeneration of intestinal cells by inhibiting the proliferation of normal intestinal mucosal cells prior to chemotherapy and by reducing the 5-FU-induced apoptosis in intestinal crypts. Thus, pretreatment with CXCL9 is a new and promising strategy for the alleviation of chemotherapy-induced intestinal mucositis in clinical settings.

Interleukin 1 receptor antagonist reduces lethality and intestinal toxicity of 5-Fluorouracil in a mouse mucositis model

Chemotherapy induced intestinal mucositis is still an unmet medical problem. 5-fluorouracil (5-Fu), a chemotherapy drug, was used to create the animal model of mucositis. Global gene expression array was applied to identify genetic signals involved in the pathogenesis of mucositis. Interleukin 1 receptor antagonist (IL-1Ra) was one of the candidates with the characteristic gene expression profile. Its temporal expression pattern correlated to the damage and regeneration phase of the small intestine after a single injection of 5-Fu to mice. Administration of recombinant IL-1Ra to the mouse model of intestinal mucositis induced by 5-Fu demonstrated its therapeutic effects to the symptoms and pathology of the disease. The IL-1Ra treatment reduced the acute lethality, accelerated their body weight recovery, and eliminated severe diarrhea. The symptomatic benefits were supported by the pathological benefits, in which the mice treated with IL-1Ra has less damage and faster recovery of the structure integrity of their small intestine than that of the mice treated with vehicle control. To deliver the therapeutics to the unmet medical condition, further mechanism and translational studies of IL-1Ra in the settings of chemotherapy induced intestinal mucositis are warranted.

Interleukin 1 receptor antagonist reduces lethality and intestinal toxicity of 5-fluorouracil in a mouse mucositis model

Chemotherapy-induced intestinal mucositis is still an unmet medical problem. 5-Fluorouracil (5-Fu), a chemotherapy drug, was used to create the animal model of mucositis. Global gene expression array was applied to identify genetic signals involved in the pathogenesis of mucositis. Interleukin 1 receptor antagonist (IL-1Ra) was one of the candidates with the characteristic gene expression profile. Its temporal expression pattern correlated to the damage and regeneration phase of the small intestine after a single injection of 5-Fu to mice. Administration of recombinant IL-1Ra to the mouse model of intestinal mucositis induced by 5-Fu demonstrated its therapeutic effects to the symptoms and pathology of the disease. The IL-1Ra treatment reduced the acute lethality, accelerated their body weight recovery, and eliminated severe diarrhea. The symptomatic benefits were supported by the pathological benefits, in which the mice treated with IL-1Ra had less damage and faster recovery of the structure integrity of their small intestine than that of the mice treated with vehicle control. To deliver the therapeutics to the unmet medical condition, further mechanism and translational studies of IL-1Ra in the settings of chemotherapy-induced intestinal mucositis are warranted.

The globalization of health research: harnessing the scientific diaspora

The scientific diaspora is a unique resource for U.S. universities. By drawing on the expertise, experience, and catalytic potential of diaspora scientists, universities can capitalize more fully on their diverse intellectual resources to make lasting contributions to global health. This article examines the unique contributions of the diaspora in international research collaborations, advantages of harnessing the diaspora and benefits to U.S. universities of fostering these collaborations, challenges faced by scientists who want to work with their home countries, examples of scientists engaging with their home countries, and specific strategies U.S. universities and donors can implement to catalyze these collaborations. The contributions of the diaspora to the United States are immense: International students enrolled in academic year 2007-2008 contributed an estimated $15 billion to the U.S. economy. As scientific research becomes increasingly global, the percentage of scientific publications with authors from foreign countries has grown from 8% in 1988 to 20% in 2005. Diaspora scientists can help build trusting relationships with scientists abroad, and international collaborations may improve the health of underserved populations at home. Although opportunities for diaspora networks are increasing, most home countries often lack enabling policies, infrastructure, and resources to effectively utilize their diaspora communities abroad. This article examines how some governments have successfully mobilized their scientific diaspora to become increasingly engaged in their national research agendas. Recommendations include specific strategies, including those that encourage U.S. universities to promote mini-sabbaticals and provide seed funding and flexible time frames.

Cryptosporidium infection causes undernutrition and, conversely, weanling undernutrition intensifies infection

Cryptosporidium parvum is a leading pathogen in children in developing countries. To investigate whether early postnatal malnutrition leads to heavier C. parvum infections, we assessed intestinal adaptation and parasite load in suckling mice during the first 2 wk of life, analogous to the first postnatal yr in humans. Undernutrition was induced by daily C57BL6J pup separation from lactating dams. Half of the pups were separated daily, for 4 hr on day 4, 8 hr on day 5, and for 12 hr from day 6 until day 14. On day 6, each pup received an oral inoculum of 10(5) to 10(7) parasites in 10-25 microl of PBS. Littermate controls received PBS alone. Stools were assessed from days 8, 11, and 14 for oocyst counts. Mice were killed on day 14, 8 days postinoculation, at the peak of the infection. Ileal and colon segments were obtained for histology, real-time and reverse transcriptase PCR, and immunoassays. Villus and crypt lengths and cross-sectional areas were also measured. Undernourished and nourished mice infected with excysted 10(6) or 10(7) oocysts exhibited the poorest growth outcomes compared with their uninfected controls. Nourished 10(6)-infected mice had comparable weight decrements to uninfected undernourished mice. Body weight and villi were additively affected by malnutrition and cryptosporidiosis. Hyperplastic crypts and heavier inflammatory responses were found in the ilea of infected malnourished mice. Undernourished infected mice exhibited greater oocyst shedding, TNF-alpha and IFN-gamma intestinal levels, and mRNA expression compared to nourished mice infected with either 10(5) or 10(6) oocysts. Taken together, these findings show that Cryptosporidium infection can cause undernutrition and, conversely, that weanling undernutrition intensifies infection and mucosal damage.

Malnutrition as an enteric infectious disease with long-term effects on child development

Malnutrition is a major contributor to mortality and is increasingly recognized as a cause of potentially lifelong functional disability. Yet, a rate-limiting step in achieving normal nutrition may be impaired absorptive function due to multiple repeated enteric infections. This is especially problematic in children whose diets are marginal. In malnourished individuals, the infections are even more devastating. This review documents the evidence that intestinal infections lead to malnutrition and that malnutrition worsens intestinal infections. The clinical data presented here derive largely from long-term cohort studies that are supported by controlled animal studies. Also reviewed are the mechanisms by which enteric infections lead to undernutrition and by which malnutrition worsens enteric infections, with implications for potential novel interventions. Further intervention studies are needed to document the relevance of these mechanisms and, most importantly, to interrupt the vicious diarrhea-malnutrition cycle so children may develop their full potential.

Alanyl-glutamine and glutamine supplementation improves 5-fluorouracil-induced intestinal epithelium damage in vitro

In this study, we have examined the role of glutamine derivatives in reducing 5-fluorouracil (5-FU)-induced epithelial damage in an undifferentiated crypt intestinal cell line, IEC-6. In this model, we have investigated proliferation indirectly by detecting the enzyme-derived formazan dye from the tetrazolium salt WST-1 in viable cells at 24 and 48 h after 5-FU treatment. Migration was measured at 12 and 24 h after razor scraping of the cell monolayer. Cell death was measured by quantifying the percentage of apoptotic and necrotic figures by flow cytometry at 12 and 24 h following 5-FU challenge. Neither glutamine nor alanyl-glutamine prevented 5-FU-induced apoptosis and necrosis in IEC-6 cells at 12 and 24 h after 5-FU challenge. However, glutamine and alanyl-glutamine enhanced migration and proliferation when compared with 5-FU-treated controls (P < 0.05). These new findings support our earlier study on the benefit of oral glutamine in enhancing epithelial recovery after 5-FU challenge.

Is the pathobiology of chemotherapy-induced alimentary tract mucositis influenced by the type of mucotoxic drug administered?

PURPOSE

Alimentary tract (AT) mucositis is a serious problem complicating cancer treatment, however, its pathobiology remains incompletely understood. Nuclear factor-kappaB (NF-kappaB) and pro-inflammatory cytokines are considered to have important roles in its development. This has been previously demonstrated in different sites of the AT following administration of irinotecan in an animal model using the Dark Agouti rat. The aim of the present study was to determine whether the changes that occur in the AT are affected by the type of mucotoxic drug.

METHODS

Female DA rats were given a single dose of either methotrexate (1.5 mg/kg intramuscularly) or 5-fluorouracil (150 mg/kg intraperitoneally). Rats were killed at 30, 60, 90 min, 2, 6, 12, 24, 48 and 72 h. Control rats received no treatment. Samples of oral mucosa, jejunum and colon were collected. Haematoxylin and eosin stained sections were examined with respect to histological evidence of damage and standard immunohistochemical techniques were used to demonstrate tissue expression of NF-kappaB, TNF, IL-1beta and IL-6.

RESULTS

Both MTX and 5-FU administration caused histological evidence of tissue damage in the AT as well as changes in tissue expression of NF-kappaB and specific pro-inflammatory cytokines. This study, however, demonstrated that there were differences in the timing of histological changes as well as the timing and intensity of pro-inflammatory cytokine tissue expression caused by the different drugs.

CONCLUSIONS

The results from this study suggest that there are differences in the mucositis pathobiology caused by different drugs. This may have important ramifications for the management of mucositis particularly with respect to the development of treatment regimens for mucositis. Further investigations are required to determine the exact pathways that lead to damage caused by the different drugs.

Gastrointestinal dysmotility in 5-fluorouracil-induced intestinal mucositis outlasts inflammatory process resolution

AIM

To evaluate gastrointestinal motility during 5-fluorouracil (5-FU)-induced intestinal mucositis.

MATERIALS AND METHODS

Wistar rats received 5-FU (150 mg kg(-1), i.p.) or saline. After the 1st, 3rd, 5th, 15th and 30th day, sections of duodenum, jejunum and ileum were removed for assessment of epithelial damage, apoptotic and mitotic indexes, MPO activity and GSH concentration. In order to study gastrointestinal motility, on the 3rd or 15th day after 5-FU treatment, gastric emptying in vivo was measured by scintilographic method, and stomach or duodenal smooth muscle contractions induced by CCh were evaluated in vitro.

RESULTS

On the third day of treatment, 5-FU induced a significant villi shortening, an increase in crypt depth and intestinal MPO activity and a decrease in villus/crypt ratio and GSH concentration. On the first day after 5-FU there was an increase in the apoptosis index and a decrease in the mitosis index in all intestinal segments. After the 15th day of 5-FU treatment, a complete reversion of all these parameters was observed. There was a delay in gastric emptying in vivo and a significant increase in gastric fundus and duodenum smooth muscle contraction, after both the 3rd and 15th day.

CONCLUSION

5-FU-induced gastrointestinal dysmotility outlasts intestinal mucositis.

Role of retinol in protecting epithelial cell damage induced by Clostridium difficile toxin A

Vitamin A (retinol), a fat-soluble vitamin, is an essential nutrient for the normal functioning of the visual system, epithelial cell integrity and growth, immunity, and reproduction. Our group has investigated the effect of high doses of oral vitamin A on early childhood diarrhea in our prospective community-based studies from Northeast Brazil and found a beneficial role in reducing the mean duration but not incidence of diarrheal episodes. In this study, we explored the role of retinol supplementation in intestinal cell lines following Clostridium difficile toxin A (TxA) challenge. C. difficile is the most common anaerobic pathogen borne with antibiotic-borne diarrhea and pseudomembranous colitis. Since retinol is critical for the integrity of tight junctions and to modulate the cell cycle, we have focused on changes in transepithelial electrical resistance (TEER) in Caco-2, a more differentiated intestinal cell line, and on models of cell proliferation, migration and viability in IEC-6 cells, an undifferentiated crypt cell line, following TxA injury. In this model, retinol therapy reduced apoptosis, improved cell migration and proliferation, and prevented the reduction in TEER, following C. difficile TxA challenge in a glutamine-free medium. These results suggest the role of retinol in protecting intestinal epithelial barrier function from C. difficile TxA enterotoxic damage.

Effect of iloprost on impaired anastomotic healing caused by 5-fluorouracil plus leucovorin

PURPOSE

This experimental study was designed to investigate whether iloprost can reverse impaired colonic healing caused by immediate postoperative intraperitoneal administration of 5-fluorouracil plus leucovorin.

METHODS

Eighty Wistar rats were randomized into four groups. After resection of a 1-cm segment of transverse colon, an end-to-end sutured anastomosis was generated. Rats received saline solution (Group 1), 5-fluorouracil plus leucovorin (Group 2), iloprost (Group 3), and 5-fluorouracil plus leucovorin plus iloprost (Group 4) intraperitoneally from the day of operation and once daily until killing. Each group was further randomized into two subgroups. Subjects were killed on the fifth (Subgroup a) and eighth (Subgroup b) postoperative days. After killing, anastomoses were examined macroscopically and graded histologically. Rats were measured for anastomotic bursting pressures and tissue hydroxyproline levels.

RESULTS

The leakage rate of the anastomoses was significantly higher in the 5-fluorouracil plus leucovorin group compared with the other groups (P = 0.049). Bursting pressure was significantly lower in 2a subgroup (5-fluorouracil plus leucovorin, postoperative Day 5) than in 4a (5-fluorouracil plus leucovorin plus iloprost, postoperative Day 5; P < 0.001). Adhesion formation was significantly higher in all b subgroups compared with the Control b subgroup. Neoangiogenesis was significantly higher in iloprost and iloprost plus 5-fluorouracil plus leucovorin subgroups compared with the 5-fluorouracil plus leucovorin subgroups. Hydroxyproline levels, collagen deposition, fibroblasts, and white cell count were significantly higher in the iloprost plus 5-fluorouracil plus leucovorin b subgroup (postoperative Day 8) compared with the 5-fluorouracil plus leucovorin b subgroup (postoperative Day 8).

CONCLUSIONS

The immediate postoperative, intraperitoneal administration of iloprost counteracts and reverses the negative effects of 5-fluorouracil plus leucovorin chemotherapy and protects colonic healing in rats.

Glutamine and alanyl-glutamine accelerate the recovery from 5-fluorouracil-induced experimental oral mucositis in hamster

INTRODUCTION

Mucositis induced by anti-neoplastic drugs is an important, dose-limiting and costly side effect of cancer therapy.

AIM

To evaluate the effect of oral glutamine and alanyl-glutamine, a more stable glutamine derivative, on 5-FU-induced oral mucositis in hamsters.

MATERIALS AND METHODS

Oral mucositis was induced by two intraperitoneal (i.p) administrations of 5-FU on the first and second days of the experiment (60 and 40 mg/kg, respectively) followed by mechanical trauma on the fourth day in male hamsters. Animals received saline, glutamine or alanyl-glutamine suspension (100 mM) 1 h before the injections of 5-FU and daily until sacrifice, on the 10th or 14th day. Macroscopic and histopathological analyses were evaluated and graded. Tissues from the cheek pouches were harvested for measurement of myeloperoxidase activity and glutathione stores. For investigation of serum concentration of glutamine, blood was obtained by heart puncture from anesthetized animals before sacrifice, on day 10.

RESULTS

Treatment with glutamine and alanyl-glutamine reduced macroscopic and histological parameters of oral mucositis, and reduced the myeloperoxidase activity on day 14, but not on day 10. The 5-FU-induced oral mucositis significantly decreased the serum glutamine levels as well as the cheek pouch glutathione stores observed on day 10. Glutamine or alanyl-glutamine administration reversed the 5-FU effects, restoring serum glutamine levels and cheek pouch glutathione stores, observed on day 10, but did not prevent oral mucositis on the tenth day.

CONCLUSION

Glutamine or alanyl-glutamine accelerated the mucosal recovery increasing mucosal tissue glutathione stores, reducing inflammatory parameters and speeding reepithelization.

Double-blinded, placebo-controlled trial on intravenous l-alanyl-l-glutamine in the incidence of oral mucositis following chemoradiotherapy in patients with head-and-neck cancer

PURPOSE

We performed this double-blinded, placebo-controlled study to determine the safety and efficacy of L-alanyl-L-glutamine in the prevention of mucositis in patients with head-and-neck cancer.

METHODS AND MATERIALS

Thirty-two patients with head-and-neck cancer were treated with chemoradiotherapy (CRT) (radiotherapy daily up to 70 Gy plus cisplatin/5-fluoruracil once a week) and were asked to participate. Twenty-nine patients received the CRT schedule and were double-blindly assigned to receive either intravenous L-alanyl-L-glutamine 0.4 g/kg weight/day or an equal volume of saline (placebo) during chemotherapy days.

RESULTS

Fourteen patients received L-alanyl-L-glutamine and 15 received placebo. Mucositis was assessed by the Objective Mucositis Score (OMS) and the World Health Organization (WHO) grading system. There was a significant difference in incidence of mucositis developed in patients receiving placebo compared with those who received L-alanyl-L-glutamine (p = 0.035). The number of patients with severe objective mucositis (OMS >1.49) was higher in the placebo group compared with the L-alanyl-L-glutamine group (67% vs. 14%, p = 0.007). L-alanyl-L-glutamine patients experienced less pain (three highest Numeric Rating Scale scores of 1.3/10 vs. 6.3/10 respectively, p = 0.008) and need for feeding tubes (14% vs. 60% respectively, p = 0.020) compared with placebo patients. No adverse effects related to the drug or the infusions were noted in either group.

CONCLUSION

For patients with head-and-neck cancer receiving CRT, intravenous L-alanyl-L-glutamine may be an effective preventive measure to decrease the severity of mucositis.

Apolipoprotein E knockout mice have accentuated malnutrition with mucosal disruption and blunted insulin-like growth factor I responses to refeeding

Apolipoprotein E (apoE) is synthesized mainly in the liver and in the brain and is critical for cholesterol metabolism and recovery from brain injury. However, although apoE mRNA increases at birth, during suckling, and after fasting in rat liver, little is known about its role in early postnatal development. Using an established postnatal malnutrition model and apoE knock-out (ko) mice, we examined the role of apoE in intestinal adaptation responses to early postnatal malnutrition. Wild-type and apoE-ko mice were separated from their lactating dams for defined periods each day (4 hours on day 1, 8 hours on day 2, and 12 hours thereafter). We found significant growth deficits, as measured by weight gain or tail length, in the apoE-ko mice submitted to a malnutrition challenge, as compared with malnourished wild type, especially during the second week of postnatal development (P < .05). In addition, apoE-ko animals failed to show growth catch-up after refeeding, compared with wild-type malnourished controls. Furthermore, we found shorter crypts and reduced villus height and area in the apoE-ko malnourished mice, compared with controls, after refeeding. Insulinlike growth factor 1 expression was also blunted in the ileum in apoE-ko mice after refeeding, compared with wild-type controls, which exhibited full insulinlike growth factor 1 expression along the intestinal crypts, villi, and in the muscular layer. Taken together, these findings suggest the importance of apoE in coping with a malnutrition challenge and during the intestinal adaptation after refeeding.

Caspase and bid involvement in Clostridium difficile toxin A-induced apoptosis and modulation of toxin A effects by glutamine and alanyl-glutamine in vivo and in vitro

Clostridium difficile is the leading cause of nosocomial bacterial diarrhea. Glutamine and its stable and highly soluble derivative alanyl-glutamine, have been beneficial in models of intestinal injury. In this study, we extend our work on the mechanisms of Clostridium difficile toxin A (TxA)-induced apoptosis in human intestinal epithelial T84 cells and evaluate the effects of glutamine and alanyl-glutamine on TxA-induced apoptosis in vitro and disruption of ileal mucosa in vivo. T84 cells were incubated with TxA (100 ng/ml) in medium with or without glutamine or alanyl-glutamine (3 to 100 mM). Apoptosis was evaluated by DNA fragmentation in vitro and the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end-labeling method in vivo. Caspase and Bid involvement were investigated by Western blotting. Ligated rabbit ileal loops were used for the evaluation of intestinal secretion, mucosal disruption, and apoptosis. TxA induced caspases 6, 8, and 9 prior to caspase 3 activation in T84 cells and induced Bid cleavage by a caspase-independent mechanism. Glutamine or alanyl-glutamine significantly reduced TxA-induced apoptosis of T84 cells by 47% and inhibited activation of caspase 8. Both glutamine and alanyl-glutamine reduced TxA-induced ileal mucosal disruption and secretion. Altogether, we further delineated the apoptosis-signaling cascade induced by TxA in T84 cells and demonstrated the protective effects of glutamine and alanyl-glutamine. Glutamine and alanyl-glutamine inhibited the apoptosis of T84 cells by preventing caspase 8 activation and reduced TxA-induced intestinal secretion and disruption.