Emerging evidence on the pathobiology of mucositis

Zinc deficits, mucositis, and mucosal macrophage perturbation: is there a relationship?

PURPOSE OF REVIEW

Mucositis is a common and therapy-limiting adverse effect of cancer treatments including radiotherapy, chemotherapy, and immunotherapy. The optimal zinc formulation, dosage, and timing of administration warrant further research as does the efficacious prevention of febrile mucositis that predisposes to febrile neutropenia.

RECENT FINDINGS

Metaanalyses concluded that zinc sulfate failed to significantly reduce the incidence or severity of chemotherapy-induced oral mucositis, whereas polaprezinc was associated with a significant reduction. Three new trials were published in 2018. The first trial found that zinc sulfate reduced the incidence and severity of chemotherapy-induced oral mucositis. The second reported that polaprezinc reduced oral mucositis in pediatric patients receiving high-dose chemotherapy for hematopoietic stem cell transplantation. The third trial demonstrated efficacy for a zinc lozenge for postoperative sore throat induced by an endotracheal intubation.

SUMMARY

Zinc deficits, dietary or induced by cancer, are common in patients with cancer. Febrile mucositis may better describe the condition linking mucositis with febrile neutropenia. Febrile mucositis disrupts treatment and may be life-threatening. A paradigm shift is needed for a more comprehensive understanding of febrile mucositis. Zinc effects on the thymic immunological network and T lymphocytes during chemoradiotherapy regimens also warrant further investigation.

The pathogenesis of mucositis: updated perspectives and emerging targets

Mucositis research and treatment are a rapidly evolving field providing constant new avenues of research and potential therapies. The MASCC/ISOO Mucositis Study Group regularly assesses available literature relating to pathogenesis, mechanisms, and novel therapeutic approaches and distils this to summary perspectives and recommendations. Reviewers assessed 164 articles published between January 2011 and June 2016 to identify progress made since the last review and highlight new targets for further investigation. Findings were organized into sections including established and emerging mediators of toxicity, potential insights from technological advances in mucositis research, and perspective. Research momentum is accelerating for mucositis pathogenesis, and with this has come utilization of new models and interventions that target specific mechanisms of injury. Technological advances have the potential to revolutionize the field of mucositis research, although focused effort is needed to move rationally targeted interventions to the clinical setting.

Use of zebrafish to model chemotherapy and targeted therapy gastrointestinal toxicity

Gastrointestinal toxicity arising from cancer treatment remains a key reason for treatment discontinuation, significantly compromising remission. There are drawbacks to the currently used in vitro and rodent models, and a lack of translatability from in vitro to in vivo work. A screening-amenable alternative in vivo model such as zebrafish would, therefore, find immediate application. This study utilized a transgenic reporter line of zebrafish, Tg(cyp2k18:egfp), that shows eGFP induction as an indicator of drug-induced pathology. Here, we investigate its utility as an alternative vertebrate model to bridge the gap between simple in vitro cellular studies and complex in vivo models for understanding gastrointestinal toxicity induced by chemotherapy and targeted therapy. Transgenic zebrafish larvae were administered afatinib or SN38, and assessed for viability and eGFP induction. Adult zebrafish were administered afatinib via oral gavage, and SN38 via intraperitoneal injection. Fish were killed after 24 h, and had gastrointestinal tracts removed and assessed for histopathological damage, goblet cell changes, and apoptosis. While treatment with either compound did not induce eGFP in the gastrointestinal tract of larvae, SN38 caused histopathological damage to adult intestines. The lack of eGFP induction may be due to poor solubility of the drugs. Chemotherapy agents with high solubility and permeability would be more amenable to these models. Further progress in this area would be greatly facilitated by the generation of robust and reproducible genetic models of zebrafish intestinal toxicity that mimic the known pathobiological pathways in rodents and humans, and can be readily induced in a short time-frame.

Impact statement

Gastrointestinal toxicity secondary to cancer treatment remains a major reason for the termination of cancer drug candidates in the development pipeline as well as withdrawal or restrictions of marketed drugs. Current cancer treatment-induced gastrointestinal toxicity models available are limited to in vitro and rodent models that lack translatability and are prohibitively expensive and time consuming. An alternative model to study cancer treatment-induced gastrointestinal toxicity that allows rapid, miniaturized, multi-organ toxicity, screening-amenable testing is therefore warranted. The newly developed Tg( cyp2k18:egfp) zebrafish reporter line was found to induce eGFP in the gastrointestinal tract if toxicity was induced in this area. This paper explored utilizing this reporter line for cancer treatment-induced gastrointestinal toxicity, but found that it was not a useful reporter line in this setting. Further progress in this area would be greatly facilitated by the generation of robust and reproducible genetic models of zebrafish intestinal toxicity that mimic the known pathobiological pathways.

Oral mucositis in head and neck cancer: Evidence-based management and review of clinical trial data

Oral Mucositis (OM) continues to be an oncologic challenge in the context of antineoplastic therapy for head and neck cancer (HNC) treatment. It is a dose-limiting toxicity of chemotherapy and radiation treatment and negatively impacts quality of life and cancer treatment efficacy. Significant effort in the field of OM has been made to help alleviate its symptoms and its subsequent clinical and economic impact. Despite these advances, the treatment of oral mucositis remains difficult and focuses on palliative measures. There are, however, many promising new biological targets currently undergoing investigation to ameliorate or help prevent the toxicity of OM in HNC. Some of these targets undergoing investigation in phase 2 and 3 clinical trials are further highlighted along with the pathobiology of OM, clinical course, prevention, and management measures.

Protective Effect of Cashew Gum (Anacardium occidentale L.) on 5-Fluorouracil-Induced Intestinal Mucositis

Intestinal mucositis is a common complication associated with 5-fluorouracil (5-FU), a chemotherapeutic agent used for cancer treatment. Cashew gum (CG) has been reported as a potent anti-inflammatory agent. In the present study, we aimed to evaluate the effect of CG extracted from the exudate of Anacardium occidentale L. on experimental intestinal mucositis induced by 5-FU. Swiss mice were randomly divided into seven groups: Saline, 5-FU, CG 30, CG 60, CG 90, Celecoxib (CLX), and CLX + CG 90 groups. The weight of mice was measured daily. After treatment, the animals were euthanized and segments of the small intestine were collected to evaluate histopathological alterations (morphometric analysis), levels of malondialdehyde (MDA), myeloperoxidase (MPO), and glutathione (GSH), and immunohistochemical analysis of interleukin 1 beta (IL-1β) and cyclooxygenase-2 (COX-2). 5-FU induced intense weight loss and reduction in villus height compared to the saline group. CG 90 prevented 5-FU-induced histopathological changes and decreased oxidative stress through decrease of MDA levels and increase of GSH concentration. CG attenuated inflammatory process by decreasing MPO activity, intestinal mastocytosis, and COX-2 expression. Our findings suggest that CG at a concentration of 90 mg/kg reverses the effects of 5-FU-induced intestinal mucositis.

Irinotecan-Induced Mucositis Is Associated with Goblet Cell Dysregulation and Neural Cell Damage in a Tumour Bearing DA Rat Model

Irinotecan-induced mucositis is a major oncological problem. Goblet cells secrete mucus, protecting the intestinal mucosa, with secretion altered during mucositis. The enteric nervous system is involved in regulating gut motility and secretion. The aim of this study was to determine whether enteric neural cells and goblet cells are altered following irinotecan treatment. Tumour-bearing Dark Agouti rats were administered a single dose of 175 mg/kg of irinotecan intraperitoneally and 0.01 mg/kg atropine subcutaneously. Experimental and untreated control rats were killed at times 6, 24, 48, 72, 96 and 120 h after treatment. Jejunum and colon samples were formalin fixed. Haematoxylin and eosin staining, Alcian Blue-PAS staining, and immunohistochemistry with S-100 antibody (neural cell marker) were carried out. Statistical analyses were carried out using Kruskal-Wallis test with Dunns post test, Mann Whitney U test and nonlinear regression. Total goblet cells decreased at 72 h compared with controls in the colon (p < 0.05). The percentage of cavitated goblet cells decreased compared to all other time points at 120 h in the colon. The number of S-100 positive cells in the submucosal plexus decreased in the colon (p = 0.0046) and in the myenteric plexus of the jejunum and colon (p = 0.0058 and p = 0.0022, respectively), when comparing treated with control. Enteric ganglia in the myenteric plexus of the jejunum decreased at 24 h and 96 h. Irinotecan-induced mucositis is associated with increases in mucus secretion, and enteric neural cell change. These changes may contribute to the pathophysiology of mucositis through the dysregulation of neural signalling.

Reduced Plasma Amino Acid Levels During Allogeneic Hematopoietic Stem Cell Transplantation Are Associated with Systemic Inflammation and Treatment-Related Complications

Patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT) are challenged by cytotoxic effects of the conditioning regimen, resulting in tissue damage, systemic inflammation, and increased metabolic demands for amino acids to regenerate damaged tissues, reconstitute hematopoietic cells, and establish antioxidant defenses. To date, few studies have addressed the role of plasma amino acid (PAA) levels during transplantation, and it remains unknown if amino acid deficiency can aggravate treatment-related morbidity. We determined plasma levels of the 23 human amino acids in 80 HSCT recipients (age 1.1 to 55.4 years) before conditioning and on days +7 and +21 post-transplant along with C-reactive protein (CRP) and IL-6 levels on day +7. Significant changes were observed in plasma concentrations of several human amino acids during HSCT. On day +7, numerous amino acids were inversely correlated with both CRP and IL-6, including glutamic acid, serine, alanine, glutamine, arginine, cysteine, glycine, histidine, lysine, tryptophan, threonine, taurine, proline, and methionine (r = -.22 to -.66; all P < .05). Patients who developed sinusoidal obstruction syndrome (SOS) had significantly lower mean total PAA levels compared with patients without SOS (2013 ng/L [95% confidence interval (CI), 1709 to 2318 ng/L] versus 2706 ng/L [95% CI, 2261 to 3150 ng/L]; P = .006), along with lower individual levels of glutamic acid, serine, arginine, glycine, lysine, valine, tryptophan, threonine, and proline on day +7 (all P < .05). Patients with severe acute graft-versus-host disease had a lower mean total PAA level (1922 ng/L [95% CI, 1738 to 2106 ng/L] versus 2649 ng/L [95% CI, 2244 to 3055 ng/L]; P = .014) and lower levels of serine, glutamine, cysteine, glycine, lysine, and threonine on day +7 (all P < .05). These results indicate a relationship between low concentrations of certain amino acids and the risk of treatment-related complications.

Prophylaxis and Management of Skin Toxicities

Skin toxicity is a common problem not only when treating breast cancer but in all cancer types. Visible on the surface, these side effects come not just with burdening symptoms but also with stigmatization. With increasing diversity in therapeutic options, dermatologic side effects are also becoming increasingly complex and more challenging for the clinician. We reviewed the most common dermatologic side effects of current anticancer therapy, including toxicity induced by chemotherapy, targeted therapy, and immunotherapy. In particular, we focus on xerosis and pruritus, (acneiform) exanthema, hand-foot syndrome, nail toxicities, alopecia, and mucositis. We propose measures for the prevention and management of these side effects based on current literature. With high incidences in both chemotherapy and targeted therapy, prophylactic measures are crucial to reducing the incidence and severity of skin toxicity and therefore key to therapy adherence. Appropriate management of these toxicities will help avoid unnecessary treatment discontinuation.

Selective MMP Inhibition, Using AZD3342, to Reduce Gastrointestinal Toxicity and Enhance Chemoefficacy in a Rat Model

BACKGROUND

The common cytotoxic mechanisms that underpin chemoefficacy and toxicity have hampered efforts to deliver effective supportive care interventions, particularly for gastrointestinal (GI) toxicity. Matrix metalloproteinases (MMPs) have been implicated in both tumor growth and GI toxicity, and as such MMP inhibitors present as a novel therapeutic avenue to simultaneously enhance treatment efficacy and reduce toxicity.

OBJECTIVES

The aim of this study was to determine the efficacy of an MMP-9/12 inhibitor, AZD3342, on tumor growth and GI toxicity in a rat model.

METHODS

Female tumor-bearing Dark Agouti rats (n = 90) were divided into 4 groups: vehicle control; methotrexate (MTX); AZD3342, and MTX + AZD3342. Tumors were measured daily (for 5 days) using digital calipers. GI toxicity was assessed using well-established clinical markers (diarrhea/weight loss), histopathological analysis, and functional assessment of intestinal barrier permeability.

RESULTS

AZD3342 delayed the onset of severe diarrhea by 1 day (vs. MTX) but was unable to improve the overall severity of diarrhea. No changes were detected in tissue morphology or intestinal barrier function. AZD3342 alone suppressed tumor growth (p = 0.003 vs. vehicle) but did not enhance the efficacy of MTX.

CONCLUSIONS

This study showed partial efficacy of AZD3342 in reducing tumor growth and delaying the onset of severe diarrhea caused by MTX in rats. We suggest further studies be undertaken targeting appropriate scheduling of AZD3342 as well as investigating different cytotoxic therapies that strongly activate MMP signaling.

Modulatory effect of a new benzopyran derivative via COX-2 blocking and down regulation of NF-κB against γ-radiation induced- intestinal inflammation

Radiotherapy is considered as a primary modality for cancer treatment which accompanied by several side effects. Protection of normal tissues from radiation effects is one of the most significant concerns for researchers. Although many compounds acting as radio protectors, only two compounds were licensed clinically. Cyclooxygenase-2 (COX-2), as an inflammatory mediator is associated with ROS production with a NF-κB gene up regulation dependent manner in normal tissues. To that extend, his study was designed to target COX-2 and NF-κB by a newly synthesized benzopyran-4-one or chromone derivative; (2E)-2-((4-oxo-4H-chromen-3-yl) methylene amino-4- nitrobenzoic acid (Ch). Exposure of mice to IRR significantly induced intestinal inflammation via overexpression of COX-2 and NF-κB which is accompanied by an increase in the levels of MDA and iNOS in tissue homogenate and in the production of TNF-α and IL-6 as inflammatory signs. Moreover, the apoptotic effect of IRR was manifested by obvious elevation in caspase-3. Interapretonial injection of Ch significantly controls the inflammatory response by blocking the COX-2 and decrease the expression NF-κB which subsequently decreases other inflammatory parameters. Thus Ch compound might be a promising nonsteroidal anti-inflammatory drug (NSAID) against radiation-induced inflammation with a specific mode of COX-2 inhibition. Further researches are needed to elucidate its molecular mechanism and its combination with radiotherapy as a protector.

Smad7 Promotes Healing of Radiotherapy-Induced Oral Mucositis without Compromising Oral Cancer Therapy in a Xenograft Mouse Model

PURPOSE

We previously reported preventive and therapeutic effects of Smad7, a multifunctional protein, on radiotherapy (RT)-induced mucositis in mice without promoting human oral cancer cell survival or migration in vitro. The current study aims to determine whether a Smad7-based biologic can treat existing oral mucositis during radiotherapy for oral cancer and whether this treatment compromises RT-induced cancer cell killing in neighboring oral cancer.Experimental Design: We transplanted human oral cancer cells into the tongues of mice and applied craniofacial irradiation to simultaneously kill tumor cells and induce oral mucositis, thus modeling RT and mucositis in oral cancer patients. We topically applied a recombinant human Smad7 protein fused with the cell-penetrating Tat tag (Tat-Smad7) to the oral mucosa of tumor-bearing mice post RT when oral mucositis began to develop.

RESULTS

Topically applied Tat-Smad7 penetrated cells in both the oral mucosa and oral cancer, attenuating TGFβ and NF-κB signaling as well as inflammation at both sites. Tat-Smad7 treatment alleviated oral mucositis with reductions in DNA damage and apoptosis in keratinocytes, but increased keratinocyte proliferation compared with vehicle-treated mucositis lesions. In contrast, adjacent oral cancer exposed to Tat-Smad7 did not show alterations in proliferation or direct DNA damage, but showed increased oxidative stress damage and apoptosis compared with tumors treated with vehicle.

CONCLUSIONS

Our results suggest that short-course Tat-Smad7 application to oral mucositis promotes its healing but does not compromise the cytotoxic effect of RT on oral cancer and has context-specific effects on oral mucosa versus oral cancer.

Gut microbiome modulation during treatment of mucositis with the dairy bacterium Lactococcus lactis and recombinant strain secreting human antimicrobial PAP

Mucositis is an inflammatory condition of the gut, caused by an adverse effect of chemotherapy drugs, such as 5-fluorouracil (5-FU). In an attempt to develop alternative treatments for the disease, several research groups have proposed the use of probiotics, in particular, Lactic Acid Bacteria (LAB). In this context, the use of recombinant LAB, for delivering anti-inflammatory compounds has also been explored. In previous work, we demonstrated that either Lactococcus lactis NZ9000 or a recombinant strain expressing an antimicrobial peptide involved in human gut homeostasis, the Pancreatitis-associated Protein (PAP), could ameliorate 5-FU-induced mucositis in mice. However, the impact of these strains on the gut microbiota still needs to be elucidated. Therefore, in the present study, we aimed to characterize the effects of both Lactococci strains in the gut microbiome of mice through a 16 S rRNA gene sequencing metagenomic approach. Our data show 5-FU caused a significant decrease in protective bacteria and increase of several bacteria associated with pro-inflammatory traits. The Lactococci strains were shown to reduce several potential opportunistic microbes, while PAP delivery was able to suppress the growth of Enterobacteriaceae during inflammation. We conclude the strain secreting antimicrobial PAP was more effective in the control of 5-FU-dysbiosis.

Pharmacological modulation of radiation-induced oral mucosal complications

Radiation-induced mucositis is a common toxicity, especially in patients with head and neck cancers. Despite recent technological advances in radiation therapy, such as intensity-modulated radiotherapy, radiation-induced mucositis is still causing treatment disruptions, negatively affecting patients' long and short term quality of life, and impacting medical resources use with economic consequences. The objective of this article was to review the latest updates in the management of radiation-induced mucositis, with a focus on pharmaceutical strategies for the prevention or treatment of mucositis. Although numerous studies analysing the prevention and management of oral radiation-induced mucositis have been conducted, there are still few reliable data to guide daily clinical practice. Furthermore, most of the tested drugs have shown no (anti-inflammatory cytokine, growth factors) or limited (palifermin) effect. Therapies for acute oral mucositis are predominantly focused on improving oral hygiene and providing symptoms control. Although low-level laser therapy proved efficient in preventing radiation-induced oral mucositis in patients with head and neck cancer, this intervention requires equipment and trained medical staff, and is therefore insufficiently developed in clinical routine. New effective pharmacological agents able to prevent or reverse radio-induced mucositis are required.

Ecological Therapeutic Opportunities for Oral Diseases

The three main oral diseases of humans, that is, caries, periodontal diseases, and oral candidiasis, are associated with microbiome shifts initiated by changes in the oral environment and/or decreased effectiveness of mucosal immune surveillance. In this review, we discuss the role that microbial-based therapies may have in the control of these conditions. Most investigations on the use of microorganisms for management of oral disease have been conducted with probiotic strains with some positive but very discrete clinical outcomes. Other strategies such as whole oral microbiome transplantation or modification of community function by enrichment with health-promoting indigenous oral strains may offer more promise, but research in this field is still in its infancy. Any microbial-based therapeutics for oral conditions, however, are likely to be only one component within a holistic preventive strategy that should also aim at modification of the environmental influences responsible for the initiation and perpetuation of microbiome shifts associated with oral dysbiosis.

Variation of Energy in Photobiomodulation for the Control of Radiotherapy-Induced Oral Mucositis: A Clinical Study in Head and Neck Cancer Patients

Oral mucositis (OM) is a frequent and severe adverse effect of therapy against head and neck cancer. Photobiomodulation with the low-power laser is known to be effective against OM, but the diversity of protocols and the possibility of stimulating residual tumor cells are still obstacles. The present study aimed to compare two doses of laser energy delivered to the oral mucosa of patients under oncologic treatment for head and neck cancer, looking for differences in the control of mucositis, as well as in the frequency of tumoral recurrences. Fifty-eight patients undergoing radiotherapy were randomized into two groups, distinguished according to the energy delivered by laser irradiation, namely, 0.25 J and 1.0 J. The groups were compared according to frequency, severity, or duration of OM, as well as the frequency of tumoral recurrences. OM was significantly less frequent in patients receiving 1.0 J of energy, but the groups did not differ regarding severity or duration of OM. Tumoral recurrence also did not vary significantly between the groups. Photobiomodulation with a higher dose of energy (1.0 J versus 0.25 J) is associated with better control of radiotherapy-induced OM and does not significantly increase the risk of neoplastic recurrence.

Phase II investigational oral drugs for the treatment of radio/chemotherapy induced oral mucositis

INTRODUCTION

Oral mucositis is a significant unmet clinical need for many cancer patients. The biological complexity of mucositis' pathogenesis provides a number of mechanistic targets suitable as pharmacologic targets. The diversity of targets has stimulated drug development in search of an effective intervention. In this paper, we review a range of agents that are currently being evaluated.

AREAS COVERED

Drugs for management of oral mucositis vary in formulation, route of administration and biological target. Most propose to interrupt the initiation of injury by suppressing activation of the innate immune response or countering oxidative stress, or minimizing downstream inflammatory responses. Overwhelmingly, the population most studied is patients being treated with concomitant chemoradiation for cancers of the head and neck as this is the cohort that most consistently suffers severe mucositis for long periods of time. The Phase 2 pipeline is robust. Preliminary data reported for a number of agents is optimistic. Genomics may be important in interpreting and comparing responses to agents across widely demographically diverse populations.

EXPERT OPINION

Oral mucositis remains a significant toxicity for patients undergoing cancer treatment. Incremental reports of successes have been noted for a number of targeted agents.

CE: Oral Care for Head and Neck Cancer Symptom Management

: An evidence-based practice change at a radiation oncology center in a large academic medical center was designed to reduce the severity of oral mucositis in adults receiving radiation treatment for head and neck cancer. In the intervention described, patients were given newly created oral care kits and educational materials to improve their oral hygiene. Evaluations were conducted at three points during the project (before radiation treatment, during week 4 to 5 of treatment, and one month after treatment). At week 4 to 5-when the severity of oral mucositis is expected to peak-patients reported improved oral hygiene practices and reduced oral mucositis severity. The authors conclude that the use of these oral care kits and educational materials lessened the effects of oral mucositis during and after radiation treatment.

Potential Benefits of Oral Cryotherapy for Chemotherapy-Induced Mucositis

Mucositis is a common side effect of cancer therapies that causes painful, erythematous lesions to develop in the gastrointestinal tract. These lesions can lead to malnutrition, increased risk for serious infection, prolonged hospital stays, and reduced quality of life. Oral cryotherapy, or the use of ice chips to cool the mucous membranes during bolus chemotherapy infusions (e.g., 5-fluorouracil [Adrucil®] and melphalan [Alkeran®]), is the most readily accessible and cost-effective intervention available. Although many factors may contribute to the development of mucositis during cancer treatment, studies have found a reduction in the incidence and the severity of mucositis with the use of oral cryotherapy.


New Frontiers in the Pathobiology and Treatment of Cancer Regimen-Related Mucosal Injury

Mucositis is a common complication of chemotherapy, radiotherapy and targeted agents. It often affects compliance to anticancer therapies as it frequently causes schedule delays, interruptions or discontinuations of treatment. Moreover, the economic impact related to the management of mucositis is topical and several estimations of additional hospital costs due to this clinical condition have been recently reported. The ability to determine risk factors for mucositis, to early detect its onset, to assess correctly the degree of this toxicity and to plan its multidisciplinary management are all key elements to guarantee the quality of life of patients and to avoid useless dose reduction or interruption of treatment. The pathogenesis of mucositis is multifactorial and it is classily subdivided into oral and gastrointestinal mucositis according to its anatomic presentation. Treatment and patients’ related factors might help in predicting the frequency and the potential degree of symptoms onset. Here we discuss about clinical presentation and pathogenesis of mucositis in relation to different kinds of treatments. Moreover, we focus on therapeutic and prevention strategies, describing past and present management according to international guidelines and the most promising new data about agents potentially able to further improve the treatment of mucositis in the next future.

Melatonin protects rats from radiotherapy-induced small intestine toxicity

Radiotherapy-induced gut toxicity is among the most prevalent dose-limiting toxicities following radiotherapy. Prevention of radiation enteropathy requires protection of the small intestine. However, despite the prevalence and burden of this pathology, there are currently no effective treatments for radiotherapy-induced gut toxicity, and this pathology remains unclear. The present study aimed to investigate the changes induced in the rat small intestine after external irradiation of the tongue, and to explore the potential radio-protective effects of melatonin gel. Male Wistar rats were subjected to irradiation of their tongues with an X-Ray YXLON Y.Tu 320-D03 irradiator, receiving a dose of 7.5 Gy/day for 5 days. For 21 days post-irradiation, rats were treated with 45 mg/day melatonin gel or vehicle, by local application into their mouths. Our results showed that mitochondrial oxidative stress, bioenergetic impairment, and subsequent NLRP3 inflammasome activation were involved in the development of radiotherapy-induced gut toxicity. Oral treatment with melatonin gel had a protective effect in the small intestine, which was associated with mitochondrial protection and, consequently, with a reduced inflammatory response, blunting the NF-κB/NLRP3 inflammasome signaling activation. Thus, rats treated with melatonin gel showed reduced intestinal apoptosis, relieving mucosal dysfunction and facilitating intestinal mucosa recovery. Our findings suggest that oral treatment with melatonin gel may be a potential preventive therapy for radiotherapy-induced gut toxicity in cancer patients.

Cannabidiol: an alternative therapeutic agent for oral mucositis?

WHAT IS KNOWN AND OBJECTIVE

Chemo- and radiotherapy are therapeutic modalities often used in patients with malignant neoplasms. They kill tumour cells but act on healthy tissues as well, resulting in adverse effects. Oral mucositis is especially of concern, due to the morbidity that it causes. We reviewed the literature on the etiopathogenesis of oral mucositis and the activity of cannabidiol, to consider the possibility of its use for the prevention and treatment of oral mucositis.

METHODS

We searched the PubMed database and selected complete articles published in English that met the inclusion criteria for the period 1998-2016. The search terms 'cannabinoids', 'cannabidiol', 'oxidative stress', 'antioxidants' and 'oral mucositis' were used.

RESULTS AND DISCUSSION

The control of oxidative stress may prevent and alleviate oral mucositis. Studies have demonstrated that cannabidiol is safe to use and possesses antioxidant, anti-inflammatory and analgesic properties.

WHAT IS NEW AND CONCLUSIONS

The literature on the use of cannabidiol in dentistry is still scarce. Studies investigating the use of cannabidiol in oral mucositis and other oxidative stress-mediated side effects of chemotherapy and radiotherapy on the oral mucosa should be encouraged.

Cytokine-mediated blood brain barrier disruption as a conduit for cancer/chemotherapy-associated neurotoxicity and cognitive dysfunction

Neurotoxicity is a common side effect of chemotherapy treatment, with unclear molecular mechanisms. Clinical studies suggest that the most frequent neurotoxic adverse events affect memory and learning, attention, concentration, processing speeds and executive function. Emerging preclinical research points toward direct cellular toxicity and induction of neuroinflammation as key drivers of neurotoxicity and subsequent cognitive impairment. Emerging data now show detectable levels of some chemotherapeutic agents within the CNS, indicating potential disruption of blood brain barrier integrity or transport mechanisms. Blood brain barrier disruption is a key aspect of many neurocognitive disorders, particularly those characterized by a proinflammatory state. Importantly, many proinflammatory mediators able to modulate the blood brain barrier are generated by tissues and organs that are targets for chemotherapy-associated toxicities. This review therefore aims to explore the hypothesis that peripherally derived inflammatory cytokines disrupt blood brain barrier permeability, thereby increasing direct access of chemotherapeutic agents into the CNS to facilitate neuroinflammation and central neurotoxicity.

Oral mucosal injury caused by mammalian target of rapamycin inhibitors: emerging perspectives on pathobiology and impact on clinical practice

In recent years oral mucosal injury has been increasingly recognized as an important toxicity associated with mammalian target of rapamycin (mTOR) inhibitors, including in patients with breast cancer who are receiving everolimus. This review addresses the state-of-the-science regarding mTOR inhibitor-associated stomatitis (mIAS), and delineates its clinical characteristics and management. Given the clinically impactful pain associated with mIAS, this review also specifically highlights new research focusing on the study of the molecular basis of pain. The incidence of mIAS varies widely (2-78%). As reported across multiple mTOR inhibitor clinical trials, grade 3/4 toxicity occurs in up to 9% of patients. Managing mTOR-associated oral lesions with topical oral, intralesional, and/or systemic steroids can be beneficial, in contrast to the lack of evidence supporting steroid treatment of oral mucositis caused by high-dose chemotherapy or radiation. However, steroid management is not uniformly efficacious in all patients receiving mTOR inhibitors. Furthermore, technology does not presently exist to permit clinicians to predict a priori which of their patients will develop these lesions. There thus remains a strategic need to define the pathobiology of mIAS, the molecular basis of pain, and risk prediction relative to development of the clinical lesion. This knowledge could lead to novel future interventions designed to more effectively prevent mIAS and improve pain management if clinically significant mIAS lesions develop.

Effect of Kangfuxin Solution on Chemo/Radiotherapy-Induced Mucositis in Nasopharyngeal Carcinoma Patients: A Multicenter, Prospective Randomized Phase III Clinical Study

Objective. To evaluate the efficacy and safety of Kangfuxin Solution, a pure Chinese herbal medicine, on mucositis induced by chemoradiotherapy in nasopharyngeal carcinoma patients. Methods. A randomized, parallel-group, multicenter clinical study was performed. A total of 240 patients were randomized to receive either Kangfuxin Solution (test group) or compound borax gargle (control group) during chemoradiotherapy. Oral mucositis, upper gastrointestinal mucositis, and oral pain were evaluated by Common Terminology Criteria for Adverse Events (CTCAE) v3.0 and the Verbal Rating Scale (VRS). Results. Of 240 patients enrolled, 215 were eligible for efficacy analysis. Compared with the control group, the incidence and severity of oral mucositis in the test group were significantly reduced (P = 0.01). The time to different grade of oral mucositis occurrence (grade 1, 2, or 3) was longer in test group (P < 0.01), and the accumulated radiation dose was also higher in test group comparing to the control group (P < 0.05). The test group showed lower incidence of oral pain and gastrointestinal mucositis than the control group (P < 0.01). No significant adverse events were observed. Conclusion. Kangfuxin Solution demonstrated its superiority to compound borax gargle on mucositis induced by chemoradiotherapy. Its safety is acceptable for clinical application.

Steamed root of Rehmannia glutinosa Libosch (Plantaginaceae) alleviates methotrexate-induced intestinal mucositis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Intestinal mucositis induced by chemotherapy is a severe clinical problem in cancer patients that currently lack effective interventions. In traditional Chinese medicine, chemotherapeutic toxicity is diagnosed as Qi and Yin deficiency, and steamed rehmannia root (SRR) is frequently prescribed to these patients. Whether SRR can prevent the adverse effects remains to be confirmed experimentally. The present study used a rat model to investigate potential efficacy and action mechanisms of SRR in attenuating the adverse effects caused by chemotherapy.

MATERIALS AND METHODS

Intraperitoneal injection of a single dose of anti-metabolite methotrexate (MTX, 25mg/kg) was given to adult Wistar rats, which also received oral gavage of water or SRR (1.08g/kg twice daily 3 days before and 4 days after MTX treatment), or calcium folinate (CF, a clinically used MTX antidote as a comparison, at 1mg/kg twice daily 36h after MTX treatment), or SRR and CF in combination. Animals were sacrificed 4 days after MTX treatment. Complete blood cell counting was carried out. Jejunum was analyzed histologically for mucosal damage, immunohistochemically for proliferating cell nuclear antigen (PCNA), and biochemically for thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH), as well as for tumor necrosis factor alpha (TNF-α).

RESULTS

MTX treatment led to weight loss, leucopenia, polycythemia, increase in large thrombocyte ratio, intestinal villus atrophy, crypt loss and reduction in PCNA positive crypt cells, increases in mucosal TBARS and TNF-α and decrease in GSH. All these alterations were inhibited by SRR administration except leucopenia, and the effects of CF or CF plus SRR supplementation were found to be inferior to those of SRR.

CONCLUSIONS

SRR can alleviate MTX-induced gut mucositis, which may be achieved by inhibiting MTX-induced oxidative stress and inflammatory response. These findings support the application of SRR in chemotherapy but not the combined application of SRR and CF.

Irinotecan-Induced Gastrointestinal Dysfunction and Pain Are Mediated by Common TLR4-Dependent Mechanisms

Strong epidemiological data indicate that chemotherapy-induced gut toxicity and pain occur in parallel, indicating common underlying mechanisms. We have recently outlined evidence suggesting that TLR4 signaling may contribute to both side effects. We therefore aimed to determine if genetic deletion of TLR4 improves chemotherapy-induced gut toxicity and pain. Forty-two female wild-type (WT) and 42 Tlr4 null (-/-) BALB/c mice weighing between 18 and 25 g (10-13 weeks) received a single 270 mg/kg (i.p.) dose of irinotecan hydrochloride or vehicle control and were killed at 6, 24, 48, 72, and 96 hours. Bacterial sequencing was conducted on cecal samples of control animals to determine the gut microbiome profile. Gut toxicity was assessed using validated clinical and histopathologic markers, permeability assays, and inflammatory markers. Chemotherapy-induced pain was assessed using the validated rodent facial grimace criteria, as well as immunologic markers of glial activation in the lumbar spinal cord. TLR4 deletion attenuated irinotecan-induced gut toxicity, with improvements in weight loss (P = 0.0003) and diarrhea (P < 0.0001). Crypt apoptosis was significantly decreased in BALB/c-Tlr4(-/-billy) mice (P < 0.0001), correlating with lower mucosal injury scores (P < 0.005). Intestinal permeability to FITC-dextran (4 kDa) and LPS translocation was greater in WT mice than in BALB/c-Tlr4(-/-billy) (P = 0.01 and P < 0.0001, respectively). GFAP staining in the lumbar spinal cord, indicative of astrocytic activation, was increased at 6 and 72 hours in WT mice compared with BALB/c-Tlr4(-/-billy) mice (P = 0.008, P = 0.01). These data indicate that TLR4 is uniquely positioned to mediate irinotecan-induced gut toxicity and pain, highlighting the possibility of a targetable gut/CNS axis for improved toxicity outcomes. Mol Cancer Ther; 15(6); 1376-86. ©2016 AACR.

Mucositis: pathobiology and management

PURPOSE OF REVIEW

Oral mucositis remains a frequent debilitating toxicity associated with drug and radiation regimens used to treat cancer. This review highlights the recent understanding of the biological basis, risk factors for, and management for oral mucositis.

RECENT FINDINGS

Prevalence and incidence data for mucositis are inconsistent and often underreported. The pathogenesis of mucositis encompasses a sequence of biological events possibly influenced by the oral microbiome and environment. Despite its frequency and severity, there is currently no effective treatment available for the majority of patients at risk. However, with the better understanding of the pathogenesis of mucositis a number of new drugs and biological agents are under investigation. Genome-wide risk prediction tools will allow the identification of patients at risk of developing mucositis.

SUMMARY

Oral mucositis is a common complication of cancer treatment that may negatively impact the patient's cancer treatment outcome. Despite its frequency and consequences, the lack of effective interventions has frustrated patients and caregivers. Fortunately, a broad range of mechanistically targeted compounds are being developed.

Topical application of Aloe vera and vitamin E on induced ulcers on the tongue of rats subjected to radiation: clinical and histological evaluation

OBJECTIVE

The aim of this study is to assess the effect of two types of antioxidants, vitamin E (VE) and Aloe vera (AV), on healing of induced oral lesions after radiation in a murine model by clinical and histological analysis.

METHODS

The animals were randomly divided into three groups of 12 animals each (400 mg VE, 70 % AV and control) and two time periods (5 and 7 days). They were irradiated with a single dose of 30 Gy, and after 24 h, a lesion was produced on the ventral tongue of each animal. The products were applied daily in their respective group until euthanasia.

RESULTS

On clinical analysis, there was a higher frequency of lesions in the animals of the control group at both periods. The area of the lesions was also greater in the control group compared with the groups AV and VE (5 days p = 0.006; 7 days p = 0.002). On microscopic analysis, the degree of inflammation differed between the study groups and experimental periods. At 5 days, the statistical difference was not significant among the groups evaluated, but at 7 days, animals in the control group showed intense inflammation, while those in groups VE and AV exhibited mild to moderate inflammation (p = 0.002).

CONCLUSION

The results suggest that VE and AV contributed to the decrease in inflammatory response and healing of the lesions induced on the tongue of rats subjected to radiation.

Combined Effects of Muricid Extract and 5-Fluorouracil on Intestinal Toxicity in Rats

Chemotherapy drugs, such as 5-fluorouracil (5FU), are the standard approach for cancer and are associated with several peripheral toxicities. We previously demonstrated that Muricidae marine molluscs exhibit chemopreventive properties. This study investigated the combined effect of muricid extract derived from Dicathais orbita, with 5FU, on intestinal toxicity in rats. Groups of rats were orally gavaged water, muricid extract, or sunflower oil, with or without 5FU (150 mg/kg). Metabolic data was collected daily and small intestinal brush border enzyme activity was measured by sucrose breath test (SBT). Blood was collected by cardiac puncture for whole blood analysis. Intestinal biopsies were taken for histopathology. Neutrophil activity was measured by myeloperoxidase activity. No additional toxicity effects were observed in rats receiving the combination of 5FU and muricid extract compared to 5FU alone, as indicated by SBT, histopathology, and myeloperoxidase activity. Intestinal integrity was protected from 5FU-induced damage in the sunflower oil vehicle group, compared to controls, as measured by SBT, villus height, and crypt depth. We concluded that combination of muricid extract and 5FU did not confer any additional intestinal toxicity, further supporting its potential as a chemopreventive food product. In this model system, sunflower oil partially protected against 5FU-induced intestinal toxicity.

Double-blind, randomized pilot study of bioadhesive chlorhexidine gel in the prevention and treatment of mucositis induced by chemoradiotherapy of head and neck cancer

Background

To evaluate, in an initial way, the effectiveness of bioadhesive chlorhexidine gel 0.2% versus placebo as a preventive and therapeutic intervention of oral mucositis induced by radiation therapy and chemotherapy in patients diagnosed with head and neck cancer treated with chemoradiotherapy.

Material and Methods

In this pilot study, 7 patients (range of age: 18- 65), having histological documented diagnosis of squamous carcinoma on the head and neck region in stage III and IV, and receiving combined radiation treatment and chemotherapy (cisplatin 100 mg/m2 IV on days 1, 22, and 43 of irradiation) were studied. Simultaneously, a topical application was performed with bioadhesive chlorhexidine gel 0.2% in the study group, and the placebo gel for the control group in 5 applications per day, from the time of initiation of cancer treatment to 2 weeks after completion of chemo-radiotherapy treatment (11 weeks of follow-up). The gradation of mucositis, pain, analgesic consumption, infectious complications, and treatment tolerance was measured.

Results

After 7 patients completed the protocol, any differences were observed between groups in an interval analysis. Mucositis, pain, and tolerance was similar in both groups.

Conclusions

Our results must be interpreted with caution due to the reduced sample size, but the use of bioadhesive chlorhexidine gel 0.2% didn’t contribute clinical improvement to the oral mucositis induced by radiation therapy and chemotherapy.

Key words: Chlorhexidine, mucositis, head and neck cancer.

A novel model of megavoltage radiation-induced oral mucositis in hamsters: Role of inflammatory cytokines and nitric oxide

PURPOSE

To design a novel model to study Cobalt-60 (Co-60)-induced radiation mucositis and to describe the pathways involved in its development.

MATERIALS AND METHODS

Hamsters' cheeks were treated with Co-60 radiation (10, 20, 30 or 35 Gy). Three days later, oral mucosa scarification was performed with a needle. The animals were euthanized at day 13 (D + 13) after irradiation. Gross and microscopic alterations were evaluated by a new score system that we developed. Also, neutrophil infiltration, tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-10, inducible nitric oxide synthase (iNOS), nitric oxide (NO) and nitrite were assessed in oral mucosa. We also tried to establish the roles of TNF-α and IL-1β and iNOS in our model using pharmacological approaches with pentoxiphylline (PTX) and aminoguanidine (AMG), respectively.

RESULTS

We found that a single administration of 35 Gy of Co-60, followed by mechanical scratches 3 days later, induced oral mucositis in hamsters. Animals with mucositis lost weight and had a survival median of 13 days, the time at which peak inflammation occurs. We noticed increased levels of NO, iNOS, TNF-α and IL-1β and a reduced concentration of IL-10. PTX partially prevented the mucositis phenotype by reducing the levels of inflammatory mediators and iNOS expression. Additionally, AMG, a selective inhibitor of iNOS, reduced Co-60-induced oral mucositis through reducing NO production.

CONCLUSION

We described a novel model of megavoltage radiation-induced oral mucositis in hamsters. TNF-α, IL-1β and NO seem to play a role in the pathophysiology of this model.

Alleviating mucositis: are we on track for a novel therapeutic?

Oral and gastrointestinal mucositis has emerged as an important toxicity of cancer therapy. In addition to supportive care measures, agents for the prevention or treatment of mucositis in specific patient populations are described in the evidence-based clinical practice guidelines published by the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology. However, there still remains an unmet clinical need for preventive and therapeutic agents in several patient populations. The successful development of such agents will rely on our improved understanding of the pathogenic mechanisms underlying mucositis. Studies are also underway on novel delivery mechanisms and risk prediction models that can facilitate the selective use of interventions for mucositis in a targeted and cost-effective manner. A large number of agents are at various stages in the clinical development pipeline. Enhanced management of this dose-limiting toxicity will allow the delivery of optimal cancer therapy and improve patient prognosis.

Matrix metalloproteinases and gut toxicity following cytotoxic cancer therapy

PURPOSE OF REVIEW

Chemotherapy is an effective anticancer treatment; however, it induces mucositis in a wide range of patients. This condition is characterized by pain and ulceration, vomiting, bloating and diarrhea, depending on the area of the alimentary tract affected. Although treatment is available for a small subset of patients suffering from mucositis, the majority rely on pain relief as their only treatment option. Much progress has been made in recent years into understanding the pathobiology underlying the development of mucositis and matrix metalloproteinases (MMPs) have been implicated as being key mediators. The purpose of this review was to evaluate recent literature implicating MMPs in mucositis.

RECENT FINDINGS

MMPs are well known for their roles in induction of inflammation and contribution to tissue injury. Recent literature provides a role for MMPs in mucositis development possibly through inflammatory pathways, alterations in extracellular matrix composition, adhesion molecules and tight junctions.

SUMMARY

Better understanding of the precise roles of MMPs is now required in order to target appropriate treatment strategies.

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

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

Biomarkers of treatment toxicity in combined-modality cancer therapies with radiation and systemic drugs: study design, multiplex methods, molecular networks

Organ toxicity in cancer therapy is likely caused by an underlying disposition for given pathophysiological mechanisms in the individual patient. Mechanistic data on treatment toxicity at the patient level are scarce; hence, probabilistic and translational linkages among different layers of data information, all the way from cellular targets of the therapeutic exposure to tissues and ultimately the patient’s organ systems, are required. Throughout all of these layers, untoward treatment effects may be viewed as perturbations that propagate within a hierarchically structured network from one functional level to the next, at each level causing disturbances that reach a critical threshold, which ultimately are manifested as clinical adverse reactions. Advances in bioinformatics permit compilation of information across the various levels of data organization, presumably enabling integrated systems biology-based prediction of treatment safety. In view of the complexity of biological responses to cancer therapy, this communication reports on a “top-down” strategy, starting with the systematic assessment of adverse effects within a defined therapeutic context and proceeding to transcriptomic and proteomic analysis of relevant patient tissue samples and computational exploration of the resulting data, with the ultimate aim of utilizing information from functional connectivity networks in evaluation of patient safety in multimodal cancer therapy.

Tachykinin peptide, substance P, and its receptor NK-1R play an important role in alimentary tract mucosal inflammation during cytotoxic therapy

The alimentary tract mucosal inflammation has been a topic of concern in oncology; though many modalities of treatment have been proposed for mucosal inflammation, the contributing adverse effects have severely affected the quality of life of patients. This review focuses on the importance of neurogenic peptide, Substance P and its receptor NK-1R in modulating the cascades of events in mucosal inflammation during cytotoxic therapy. There are various preclinical and clinical models showing increased expression of Substance P/NK-1R in ionizing radiation and chemotherapy, but only very few preclinical studies to our knowledge have highlighted or examined its role in mucosal inflammation. Hence, the importance of neuropeptide involved in the inflammatory events in mucosal inflammation in cytotoxic therapy could be a major breakthrough for future research purposes and treatment. The factors contributing to the severity of tissue reactions have been multietiogenic; thus, resultant treatment also has to be directed toward multiple contributing factors. This review also focuses on the significance of care strategy to be adopted in alimentary tract mucositis when multietiogenic factors are taken into consideration.

Mucositis care in acute leukemia and non-Hodgkin lymphoma patients undergoing high-dose chemotherapy

PURPOSE

This study intends to provide new insights into the incidence and care of mucositis by the epidemiological characterization of patients with hematological malignancy treated at our institution. It also aims to understand the effectiveness of several treatments used.

METHODS

This is a longitudinal observational single-center study-convenience sample-which includes malignant hematologic inpatients submitted to high-dose CT from February to August 2012. We registered epidemiological data, diagnosis, oral mucositis daily questionnaire (OMDQ), World Health Organization (WHO) oral toxicity scale, and supportive medications used for mucositis.

RESULTS

We evaluated 30 patients who had 73 episodes of hospitalization, having recorded the development of mucositis in 21.9 % (n = 16) episodes (22 patients with acute leukemia (AL) and 8 patients with non-Hodgkin lymphoma (NHL)). Grades 3-4 mucositis was reported in 4.1 % of the total episodes. The results of OMDQ showed some limitations in the quality of life, of patients with mucositis, related with the ability to eat and drink due to mouth pain (p < 0.001). In patients with NHL and AL, neutropenia entails an increased risk of mucositis (p < 0.001). Patients who did not initiate early prophylaxis with conservative measures developed mucositis earlier (p < 0.05).

CONCLUSIONS

The incidence of mucositis is high, being reported mainly in AL patients, with limitations in quality of life. Grade 4 neutropenia increases mucositis risk. Early prophylaxis with basic oral care may delay mucositis. Further studies are crucial to characterize mucositis epidemiology, physiopathology, and its management.