Evaluation of Radiation-Induced Oral Mucositis by Optical Coherence Tomography

Systematic Review of Genetic Polymorphisms Associated with Acute Pain Induced by Radiotherapy for Head and Neck Cancers

Background/objective

Pain is the most common acute symptom following radiation therapy (RT) for head and neck cancer (HNC). The multifactorial origin of RT-induced pain makes it highly challenging to manage. Multiple studies were conducted to identify genetic variants associated with cancer pain, however few of them focused on RT-induced acute pain. In this review, we summarize the potential mechanisms of acute pain after RT in HNC and identify genetic variants associated with RT-induced acute pain and relevant acute toxicities.

Methods

A comprehensive search of Ovid Medline, EMBASE and Web of Science databases using terms including "Variants", "Polymorphisms", "Radiotherapy", "Acute pain", "Acute toxicity" published up to February 28, 2022, was performed by two reviewers. Review articles and citations were reviewed manually. The identified SNPs associated with RT-induced acute pain and toxicities were reported, and the molecular functions of the associated genes were described based on genetic annotation using The Human Gene Database; GeneCards.

Results

A total of 386 articles were identified electronically and 8 more articles were included after manual search. 21 articles were finally included. 32 variants in 27 genes, of which 25% in inflammatory/immune response, 20% had function in DNA damage response and repair, 20% in cell death or cell cycle, were associated with RT-inflammatory pain and acute oral mucositis or dermatitis. 4 variants in 4 genes were associated with neuropathy and neuropathic pain. 5 variants in 4 genes were associated with RT-induced mixed types of post-RT-throat/neck pain.

Conclusion

Different types of pain develop after RT in HNC, including inflammatory pain; neuropathic pain; nociceptive pain; and mixed oral pain. Genetic variants involved in DNA damage response and repair, cell death, inflammation and neuropathic pathways may affect pain presentation post-RT. These variants could be used for personalized pain management in HNC patients receiving RT.

High molecular weight hyaluronic acid drastically reduces chemotherapy-induced mucositis and apoptotic cell death

Oral and intestinal mucositis (OIM) are debilitating inflammatory diseases initiated by oxidative stress, resulting in epithelial cell death and are frequently observed in cancer patients undergoing chemo-radiotherapy. There are currently few preventative strategies for this debilitating condition. Therefore, the development of a safe and effective mucositis mitigating strategy is an unmet medical need. Hyaluronic acid (HA) preparations have been tentatively used in oral mucositis. However, the protective effects of HA in chemotherapy-induced mucositis and their underlying mechanisms remain to be fully elucidated. This study aimed to assess these mechanisms using multiple formulations of enriched HA (Mucosamin^®), cross-linked (xl-), and non-crosslinked high molecular weight HA (H-MW-HA) in an oxidative stress-induced model of human oral mucosal injury in vitro and an in vivo murine model of 5-flurouracil (5-FU)-induced oral/intestinal mucositis. All tested HA formulations protected against oxidative stress-induced damage in vitro without inducing cytotoxicity, with H-MW-HA also significantly reducing ROS production. Daily supplementation with H-MW-HA in vivo drastically reduced the severity of 5-FU-induced OIM, prevented apoptotic damage and reduced COX-2 enzyme activity in both the oral and intestinal epithelium. In 5-FU-injected mice, HA supplementation also significantly reduced serum levels of IL-6 and the chemokine CXCL1/KC, while the serum antioxidant activity of superoxide dismutase was elevated. Our data suggest that H-MW-HA attenuates 5-FU-induced OIM, at least partly, by impeding apoptosis, inhibiting of oxidative stress and suppressing inflammatory cytokines. This study supports the development of H-MW-HA preparations for preventing OIM in patients receiving chemotherapy.

Efficacy of mesenchymal stem cell therapy in rodent models of radiation-induced xerostomia and oral mucositis: a systematic review

BACKGROUND

Radiation-induced xerostomia and oral mucositis are serious complications of radiation therapy for head and neck cancers. Current treatment options have limited efficacy. Mesenchymal stem cell (MSC) therapy has shown promising results in supporting the restoration of glandular secretion function and the regeneration of damaged tissues. This study aim to (1) assess the quality of evidence for MSCs treatment in rodent models of radiation-induced oral complications and (2) determine whether MSCs can improve the therapeutic effect of radiation-induced oral mucositis.

METHODS

Intervention studies using MSCs in rodent models were comprehensively retrieved in the Pubmed, Medline, Embase, Web of Science, and Cochrane library databases on June 1, 2022. The quality of all in vivo experiments was assessed using SYRCLE, and this article is written following the PRISMA guidelines.

RESULTS

A total of 12 studies were included in this systematic review. The study found that in animal models of radiation-induced xerostomia, MSCs could increase salivary protein secretion, improve SFR, shorten the salivary lag time, anti-apoptosis, etc. In animal models of radiation-induced oral mucositis, MSCs improve the micromorphology and macromorphology of RIOM. Moreover, the effect of MSCs on the modification of ulcer duration and latency may be related to the time of MSCs transplantation but further studies are needed.

CONCLUSION

The results of our systematic review suggest that MSCs appeared to be effective in the treatment of radiation-induced xerostomia and oral mucositis.

Characterization of a novel dual murine model of chemotherapy-induced oral and intestinal mucositis

Oral and intestinal mucositis are debilitating inflammatory diseases observed in cancer patients undergoing chemo-radiotherapy. These are devastating clinical conditions which often lead to treatment disruption affecting underlying malignancy management. Although alimentary tract mucositis involves the entire gastrointestinal tract, oral and intestinal mucositis are often studied independently utilizing distinct organ-specific pre-clinical models. This approach has however hindered the development of potentially effective whole-patient treatment strategies. We now characterize a murine model of alimentary tract mucositis using 5-Fluorouracil (5-FU). Mice were given 5-FU intravenously (50 mg/kg) or saline every 48 h for 2 weeks. Post initial injection, mice were monitored clinically for weight loss and diarrhea. The incidence and extent of oral mucositis was assessed macroscopically. Microscopical and histomorphometric analyses of the tongue and intestinal tissues were conducted at 3 interim time points during the experimental period. Repeated 5-FU treatment caused severe oral and intestinal atrophy, including morphological damage, accompanied by body weight loss and mild to moderate diarrhea in up to 77.8% of mice. Oral mucositis was clinically evident throughout the observation period in 88.98% of mice. Toluidine blue staining of the tongue revealed that the ulcer size peaked at day-14. In summary, we have developed a model reproducing the clinical and histologic features of both oral and intestinal mucositis, which may represent a useful in vivo pre-clinical model for the study of chemotherapy-induced alimentary tract mucositis and the development of preventative therapies.

Oral Cancer Screening by Artificial Intelligence-Oriented Interpretation of Optical Coherence Tomography Images

Early diagnosis of oral cancer is critical to improve the survival rate of patients. The current strategies for screening of patients for oral premalignant and malignant lesions unfortunately miss a significant number of involved patients. Optical coherence tomography (OCT) is an optical imaging modality that has been widely investigated in the field of oncology for identification of cancerous entities. Since the interpretation of OCT images requires professional training and OCT images contain information that cannot be inferred visually, artificial intelligence (AI) with trained algorithms has the ability to quantify visually undetectable variations, thus overcoming the barriers that have postponed the involvement of OCT in the process of screening of oral neoplastic lesions. This literature review aimed to highlight the features of precancerous and cancerous oral lesions on OCT images and specify how AI can assist in screening and diagnosis of such pathologies.

Efficacy of Nutrients in Reducing the Symptoms of Radiation Induced Oral Mucositis in a Hamster Model

Radiation-induced oral mucositis (RIOM) is a painful, dose-limiting toxicity in cancer therapy. RIOM was induced by radiation on the left buccal pouch mucosa of Golden Syrian hamsters (n = 8/group). Animals were treated topically with polyphenols (Curcumin or Quercetin) or amino acids/metabolite mixtures (Alanyl-Glutamine or Arginine + Glutamine + β-Hydroxy β-methylbutyric acid (Arg/Gln/HMB)) for over 20 day. Progression of RIOM was assessed using a standard visual scoring six-point scale, for differences in severity of mucositis (score ≥3) (Chi-square analysis) and in the daily group scores (Mann-Whitney rank sum test). Compared to the controls, there was a significant reduction in number of days with severe RIOM (score ≥3) in the treatment groups: Curcumin (50 μg/ml) = 17%; Control = 38.5%, p < 0.001; Quercetin (50 μg/ml) = 27.6% and Quercetin (100 μg/ml) = 25%; Control = 41.3%, p = 0.007 and p = 0.001, respectively; Arg/Gln/HMB (50 mg/ml) = 31.9%; Control = 50.0%, p = 0.040. In addition, Curcumin (50 μg/ml), Quercetin (100 μg/ml) and Arg/Gln/HMB (100 mg/ml) groups had lower mucositis scores (≥3) on at least two consecutive time points over the course of the study than their respective controls. There were no significant group differences in deaths or body weight. This study demonstrates the potential benefits of topical application of either plant polyphenols or amino acid/metabolite mixtures in addressing severity and progression of RIOM.

3D-printed individualized tooth-borne tissue retraction devices compared to conventional dental splints for head and neck cancer radiotherapy: a randomized controlled trial

BACKGROUND

Despite modern treatment techniques, radiotherapy (RT) in patients with head and neck cancer (HNC) may be associated with high rates of acute and late treatment-related toxicity. The most effective approach to reduce sequelae after RT is to avoid as best as possible healthy tissues and organs at risk from the radiation target volume. Even small geometric changes can lead to a significant dose reduction in normal tissue and better treatment tolerability. The major objective of the current study is to investigate 3D printed, tooth-borne tissue retraction devices (TRDs) compared to conventional dental splints for head and neck RT.

METHODS

In the current two-arm randomized controlled phase II trial, a maximum of 34 patients with HNC will be enrolled. Patients will receive either TRDs or conventional dental splints (randomization ratio 1:1) for the RT. The definition of the target volume, modality, total dose, fractionation, and imaging guidance is not study-specific. The primary endpoint of the study is the rate of acute radiation-induced oral mucositis after RT. The quality of life, local control and overall survival 12 months after RT are the secondary endpoints. Also, patient-reported outcomes and dental status, as well as RT plan comparisons and robustness analyzes, will be assessed as exploratory endpoints. Finally, mesenchymal stem cells, derived from the patients' gingiva, will be tested in vitro for regenerative and radioprotective properties.

DISCUSSION

The preliminary clinical application of TRD showed a high potential for reducing acute and late toxicity of RT in patients with HNC. The current randomized study is the first to prospectively investigate the clinical tolerability and efficacy of TRDs for radiation treatment of head and neck tumors.

TRIAL REGISTRATION

ClinicalTrials.gov; NCT04454697; July 1st 2020; https://clinicaltrials.gov/ct2/show/record/NCT04454697 .

GM-1111 reduces radiation-induced oral mucositis in mice by targeting pattern recognition receptor-mediated inflammatory signaling

PURPOSE

Oral mucositis (OM) is a common, painful side effect of radiation therapy used for the treatment of head and neck cancer (HNC). Activation of the innate immune system upon irradiation has been identified as a key precipitating event of OM. To better understand OM's pathogenesis, we studied pattern recognition receptors (PRRs) and their downstream pro-inflammatory cytokines in a mouse model of radiation-induced OM. We also tested therapeutic efficacy of GM-1111 that targets innate immune system to reduce radiation-induced OM.

METHODS AND MATERIALS

The pathogenesis of OM was studied in a single X-ray induced mouse model. The severity of OM was measured by visual and microscopical examinations. The irradiation-induced changes of PRRs and their downstream effector cytokine gene expression levels were determined. The efficacy of GM-1111 to reduce OM was tested in single and fractionated irradiation mouse models. The impact of the drug on tumor response to radiation therapy was also tested in a mouse model of human HNC.

RESULTS

Radiation-induced tissue ulcerations were radiation-dosage and -time dependent. The lesions showed selective increases in PRR and pro-inflammatory cytokine gene expression levels. Once daily administration of GM-1111 (≥30 mg/kg, s.c.) significantly reduced the severity and the incidence of OM. The drug had little effect on PRRs but significantly inhibited downstream pro-inflammatory cytokine genes. GM-1111 did not interfere radiation therapy to induce HNC SCC-25 tumor regression. Instead, we observed significant drug-induced tumor regression.

CONCLUSIONS

Radiation induces tissue damages. The increased expression levels of PRRs and their downstream pro-inflammatory cytokine genes in the damaged tissues suggest their important contribution to the pathogenesis of OM. Drug GM-1111 that targets these innate immune molecules may be a potential drug candidate as an intervention for OM.

Effects of oral moisturizing gel containing propolis following head and neck radiotherapy: randomized controlled pilot trial

Aim

Topical administration of oral gel may reduce radiotherapy-related oral complications. The aim of this study was to examine clinical and microbiological effects of self-administration of different gel formulations to oral mucosa in head and neck cancer patients.

Materials and methods

Twenty-seven subjects were recruited from outpatients who underwent radiotherapy of at least 50 Gy to the head and neck area. They were randomly assigned to oral gel with the following different ingredients: placebo, chlorhexidine, curry leaf, propolis, and turmeric. Before and after intervention, oral symptoms were evaluated, and nine oral pathogens in saliva were also quantified using real-time PCR.

Results

Twenty-five subjects completed the study and their data were analyzed. The number of Porphyromonas gingivalis in saliva significantly decreased after treatment with propolis gel, but not after any other treatments. Propolis gel treatment also relieved oral pain in all subjects who had oral pain at the baseline.

Conclusions

Topical administration with propolis gel may not only reduce P. gingivalis carriage in saliva, but also relieve oral pain.

Discussion

A future larger-scale clinical trial of oral propolis gel is needed to determine its clinical efficacy in radiotherapy-related oral complications of head and neck cancer patients.

The Effects of Early Nutritional Intervention on Oral Mucositis and Nutritional Status of Patients With Head and Neck Cancer Treated With Radiotherapy

Radiation-induced oral mucositis (RIOM) is a common side effect after radiotherapy (RT) in head and neck cancer (HNC) patients. RIOM patients with severe pain have difficulty in eating, which increases the incidence of malnutrition and affects patients' quality of life and the process of RT. The mechanism of RIOM is not fully understood, and inflammatory response and oxidative stress appear to be important for RIOM occurrence and development. The nutritional status of patients is very important for their RT tolerance and recovery. Malnutrition, which can lead to anemia, low protein, decreased immunity and other problems, is an important clinical factor affecting tumor progression and treatment. Recent studies have shown that early nutritional intervention can ameliorate oral mucositis and nutritional status of patients with HNC. However, in clinical practice, early nutritional intervention for patients with HNC is not a conventional intervention strategy. Therefore, this review summarized the possible pathogenesis of RIOM, commonly used assessment tools for malnutrition in patients, and recent studies on the effects of early nutritional interventions on RIOM and nutritional status of patients with HNC. We hope to provide the basis and reference for the clinical application of early nutritional intervention models.

Vitamin D oral gel for prevention of radiation-induced oral mucositis: A randomized clinical trial

OBJECTIVES

The aim of this clinical trial is to evaluate the effectiveness of topical oral vitamin D gel in prevention of radiation-induced oral mucositis.

MATERIAL AND METHODS

A three-armed randomized controlled clinical trial on forty-five head and neck cancer patients was conducted. First group: conventional treatment. Second group: Topical oral vitamin D gel. Third group: topical oral vitamin D gel plus the conventional treatment. All the patients were examined clinically three and six weeks after the start of radiotherapy for pain and WHO mucositis score.

RESULTS

After 6 weeks of radiotherapy, (33.5%) the patients in control group developed high-grade severity of oral mucositis while the patients in the two-test groups "vitamin D group and combined therapy group" remained with low-grade severity or with complete remission. Mean pain scores showed a significant decrease in the combined therapy group and to a close degree in vitamin D group rather than the control group.

CONCLUSION

Topical oral vitamin D gel has a beneficial effect in lowering oral mucositis development and in reducing pain sensation during the radiation period especially when combined with conventional therapeutic agents.

Effects of N-acetylcysteine inhalation therapy on the quality of life of patients with head and neck cancer who are receiving radiation therapy: a prospective non-randomized controlled multi-center study

BACKGROUNDS AND PURPOSE

Radiation therapy is an important mode of treatment for patients with head and neck cancers, but some associated complications can reduce the quality of life. We investigated whether N-acetylcysteine inhalation therapy improved the quality of life of such patients.

MATERIALS AND METHODS

We designed a prospective, non-randomized controlled multi-center study involving 10 institutions. We enrolled 120 patients (80 in the experimental group and 40 in the control group). Patients in the experimental group inhaled nebulized liquid N-acetylcysteine (2400 mg daily) for 8 weeks from the start of radiation therapy. Quality of life was assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire H&N 35.

RESULTS

N-acetylcysteine inhalation was not associated with any side effect or discomfort. The reduction in painkiller use from the end of N-acetylcysteine inhalation therapy to the 1-month follow-up was greater in the experimental group than in the control group (P = 0.014). Dry mouth symptoms also improved significantly in the experimental group (P = 0.019).

CONCLUSION

N-acetylcysteine inhalation improves the quality of life of patients with head and neck cancers who are receiving radiation therapy, without any specific side effect.

Regulation of HMGB1 release protects chemoradiotherapy-associated mucositis

Oral mucositis (OM) is a common complication in cancer patients undergoing anticancer treatment. Despite the clinical and economic consequences of OM, there are no drugs available for its fundamental control. Here we show that high-mobility group box 1 (HMGB1), a "danger signal" that acts as a potent innate immune mediator, plays a critical role in the pathogenesis of OM. In addition, we investigated treatment of OM through HMGB1 blockade using NecroX-7 (tetrahydropyran-4-yl)-[2-phenyl-5-(1,1-dioxo-thiomorpholin-4-yl)methyl-1Hindole-7-yl]amine). NecroX-7 ameliorated basal layer epithelial cell death and ulcer size in OM induced by chemotherapy or radiotherapy. This protective effect of NecroX-7 was mediated by inhibition of HMGB1 release and downregulation of mitochondrial oxidative stress. Additionally, NecroX-7 inhibited the HMGB1-induced release of tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β, and macrophage inflammatory protein (MIP)-1β, as well as the expression of p53-upregulated modulator of apoptosis (PUMA) and the excessive inflammatory microenvironment, including nuclear factor-kB (NF-kB) pathways. In conclusion, our findings suggest that HMGB1 plays a key role in the pathogenesis of OM; therefore, blockade of HMGB1 by NecroX-7 may be a novel therapeutic strategy for OM.

Cancer pain: where are we now?

Increasing numbers of those living with and beyond cancer presents a clinical challenge for pain specialists. A large proportion of these patients experience pain secondary to their disease or its treatment, impeding rehabilitation and significantly impacting upon their quality of life. The successful management of this pain presents a considerable challenge. This review aims to outline current concepts and treatment options, while considering nuances within pain assessment and the use of large-scale data to help guide further advances.

Dimethyl Sulfoxide Prevents Radiation-Induced Oral Mucositis Through Facilitating DNA Double-Strand Break Repair in Epithelial Stem Cells

PURPOSE

Oral mucositis is one of the most prevalent side effects in patients undergoing radiation therapy for head and neck cancers. Current therapeutic agents such as palifermin recombinant human keratinocyte growth factor and amifostine do not efficiently or fully prevent mucositis. Dimethyl sulfoxide (DMSO), a free-radical scavenger, has shown therapeutic benefits in many preclinical and clinical studies. This study aimed to investigate the efficacy of DMSO in a clinically relevant mouse model of acute, radiation-induced oral mucositis.

METHODS AND MATERIALS

Oral mucositis was induced by a high single and fractioned irradiation of the head and neck area in C57BL/6J mice, and the effects of DMSO (by intraperitoneal injection) were assessed by macroscopic and histopathological examination. Epithelial stem and progenitor cells were analyzed by immunohistochemical staining of p63 and Ki-67, and DNA double-strand breaks (DSBs) were visualized by immunofluorescence detection of γ-H2AX. Tumor xenograft was obtained using CAL-27 cells.

RESULTS

Pretreatment with DMSO protected the oral mucosa from severe acute radiation injury, reduced the extent of radiation-induced weight loss, and had no significant effects on tumor weight in irradiated or nonirradiated xenograft mice. Furthermore, the efficacy of DMSO was superior to that of recombinant human keratinocyte growth factor and amifostine. DMSO treatment prevented the loss of proliferative lingual epithelial stem and progenitor cells upon irradiation. More interestingly, the average levels of γ-H2AX foci were significantly decreased in p63-positive epithelial stem cells at 6 hours, but not at 2 hours, after irradiation, indicating that DMSO facilitated DNA DSB repair rather than suppressing the indirect action of irradiation.

CONCLUSIONS

DMSO prevents the loss of proliferative lingual epithelial stem and progenitor cells upon irradiation by facilitating DNA DSB repair, thereby protecting against radiation-induced mucositis without tumor protection. Given its high efficacy and low toxicity, DMSO could be a potential treatment option to prevent radiation-induced oral mucositis.

Neurturin Gene Therapy Protects Parasympathetic Function to Prevent Irradiation-Induced Murine Salivary Gland Hypofunction

Head and neck cancer patients treated with irradiation often present irreversible salivary gland hypofunction for which no conventional treatment exists. We recently showed that recombinant neurturin, a neurotrophic factor, improves epithelial regeneration of mouse salivary glands in ex vivo culture after irradiation by reducing apoptosis of parasympathetic neurons. Parasympathetic innervation is essential to maintain progenitor cells during gland development and for regeneration of adult glands. Here, we investigated whether a neurturin-expressing adenovirus could be used for gene therapy in vivo to protect parasympathetic neurons and prevent gland hypofunction after irradiation. First, ex vivo fetal salivary gland culture was used to compare the neurturin adenovirus with recombinant neurturin, showing they both improve growth after irradiation by reducing neuronal apoptosis and increasing innervation. Then, the neurturin adenovirus was delivered to mouse salivary glands in vivo, 24 hr before irradiation, and compared with a control adenovirus. The control-treated glands have ∼50% reduction in salivary flow 60 days post-irradiation, whereas neurturin-treated glands have similar flow to nonirradiated glands. Further, markers of parasympathetic function, including vesicular acetylcholine transporter, decreased with irradiation, but not with neurturin treatment. Our findings suggest that in vivo neurturin gene therapy prior to irradiation protects parasympathetic function and prevents irradiation-induced hypofunction.

In-vivo longitudinal imaging of microvascular changes in irradiated oral mucosa of radiotherapy cancer patients using optical coherence tomography

Mucositis is the limiting toxicity of radio(chemo)therapy of head and neck cancer. Diagnostics, prophylaxis and correction of this condition demand new accurate and objective approaches. Here we report on an in vivo longitudinal monitoring of the oral mucosa dynamics in 25 patients during the course of radiotherapy of oropharyngeal and nasopharyngeal cancer using multifunctional optical coherence tomography (OCT). A spectral domain OCT system with a specially-designed oral imaging probe was used. Microvasculature visualization was based on temporal speckle variations of the full complex signal evaluated by high-pass filtering of 3D data along the slow scan axis. Angiographic image quantification demonstrated an increase of the vascular density and total length of capillary-like-vessels before visual signs or clinical symptoms of mucositis occur. Especially significant microvascular changes compared to their initial levels occurred when grade two and three mucositis developed. Further, microvascular reaction was seen to be dose-level dependent. OCT monitoring in radiotherapy offers a non-invasive, convenient, label-free quantifiable structural and functional volumetric imaging method suitable for longitudinal human patient studies, furnishing fundamental radiobiological insights and potentially providing useful feedback data to enable adaptive radiotherapy (ART).

Microvascular imaging and monitoring of human oral cavity lesions in vivo by swept-source OCT-based angiography

We report the development of optical coherence tomography- (OCT) based angiography (OCTA) to image blood flow within microcirculatory tissue beds in human oral cavity in vivo with a field of view at 10 mm × 10 mm. Three-dimensional (3D) structural and vascular images of labial mucosa tissue are obtained at a single 3D acquisition. Pathologic mucosal sites with mouth ulcers are examined using the OCT tomograms and angiograms, upon which to monitor the lesion healing process over a period of 2 weeks. Quantitative metrics of the capillary loop density within the lamina propria layer are evaluated, providing statistically significant difference between healthy and diseased conditions over time. Furthermore, tissue anatomy and vessel morphology of other susceptible sites to ulcer, such as tongue, alveolar mucosa, and labial frenulum, are also imaged to demonstrate the promise of the proposed method as a clinically useful tool for the diagnosis and monitoring of therapeutic treatment of oral tissue abnormalities.

Chemotherapy Induces Oral Mucositis in Mice Without Additional Noxious Stimuli

Oral mucositis (OM) is a serious side effect of cancer chemotherapy. The pathobiology of oral mucositis remains incompletely understood due to lack of appropriate models which recapitulate the human condition. Existing rodent models are intraperitoneal and require radiation, chemical or mechanical injury to the chemotherapy protocol to induce oral lesions. We aimed to develop an OM mouse model that is induced solely by chemotherapy and reproduces macroscopic, histopathologic and inflammatory characteristics of the human condition. Female C57BL/6 mice were given intravenous 5-Fluorouracil (5-FU) injections every 48 hours, for 2 weeks. A high daily dose of intraperitoneal administration was tested for comparison. Mice were monitored daily for weight loss. Epithelial histomorphometric analyses in tongue, esophageal and intestinal tissues were conducted coupled with assessment of apoptosis, cell proliferation, neutrophilic infiltration and the integrity of adherens junctions by immunohistochemistry. Neutropenia was assessed in peripheral blood and bone marrow. Tissues were analyzed for pro-inflammatory cytokines at the protein and mRNA levels. Daily intraperitoneal administration of 5-FU led to rapid weight loss and intestinal mucositis, but no oral inflammatory changes. Intravenous administration triggered atrophy of the oral and esophageal epithelium accompanied by reduction in cell proliferation and increased apoptosis. Coincidental with these changes were up-regulation of NF-κB, TNFα, IL-1β, GM-CSF, IL-6 and KC. Despite neutropenia, increased oral neutrophilic infiltration and reduced E-cadherin was observed in oroesophageal mucosae. We developed a novel experimental tool for future mechanistic studies on the pathogenesis of chemotherapy-induced OM.

Radiation-Induced Oral Mucositis

Radiation-induced oral mucositis (RIOM) is a major dose-limiting toxicity in head and neck cancer patients. It is a normal tissue injury caused by radiation/radiotherapy (RT), which has marked adverse effects on patient quality of life and cancer therapy continuity. It is a challenge for radiation oncologists since it leads to cancer therapy interruption, poor local tumor control, and changes in dose fractionation. RIOM occurs in 100% of altered fractionation radiotherapy head and neck cancer patients. In the United Sates, its economic cost was estimated to reach 17,000.00 USD per patient with head and neck cancers. This review will discuss RIOM definition, epidemiology, impact and side effects, pathogenesis, scoring scales, diagnosis, differential diagnosis, prevention, and treatment.

Adipose mesenchymal stromal cells minimize and repair radiation-induced oral mucositis

BACKGROUND AIMS

Mesenchymal stromal cells (MSCs) have been used to minimize and repair radiation-induced normal tissue injury in the intestine, salivary gland, liver, skin, lungs and cardiac muscle. This study investigated the ability of adipose tissue-derived MSCs (aMSCs) to minimize and/or repair single dose radiation-induced oral mucositis (RIOM).

METHODS

Syngenic phenotypically and functionally characterized BALB/c mouse aMSCs were implanted intraperitoneally in a RIOM mouse model with different dosing protocols. Response was quantified macroscopically, microscopically and by using different histological and clinically relevant parameters.

RESULTS

Irradiation at 18 Gy generated a self-resolved single-dose RIOM BALB/c mouse model with 5.6 ± 0.3 days mean duration (95% confidence interval (CI) 4.233-7.1 days) and 100% survival rate. Intraperitoneal implantation of 5 doses of 2.5 million freshly cultured syngenic aMSCs significantly and reproducibly reduced RIOM ulcer duration to 1.6 ± 0.3 days (95% CI 0.0233-3.1 days, a 72% reduction in RIOM ulcer duration), ulcer size and ulcer floor epithelial height. The therapeutic benefits were significantly dependent on dose size and frequency, number of doses, and therapy onset time. aMSCs therapy significantly minimized the RIOM-related weight loss, accelerated the weight gain and improved irradiated animals' hydration and nutritional status. aMSCs therapy did not potentiate head and neck cancer in vitro.

CONCLUSIONS

Syngenic freshly cultured aMSCs significantly minimized and repaired radiation-induced oral mucositis with a 72% reduction in ulcer duration. aMSCs dose size and frequency, number of doses and therapy onset time are the main keys for optimized therapeutic outcome. aMSCs therapy did not stimulate Head and Neck cancer cell growth in-vitro.

Single-Dose Radiation-Induced Oral Mucositis Mouse Model

The generation of a self-resolved radiation-induced oral mucositis (RIOM) mouse model using the highest possibly tolerable single ionizing radiation (RT) dose was needed in order to study RIOM management solutions. We used 10-week-old male BALB/c mice with average weight of 23 g for model production. Mice were treated with an orthovoltage X-ray irradiator to induce the RIOM ulceration at the intermolar eminence of the animal tongue. General anesthesia was injected intraperitoneally for proper animal immobilization during the procedure. Ten days after irradiation, a single RT dose of 10, 15, 18, 20, and 25 Gy generated a RIOM ulcer at the intermolar eminence (posterior upper tongue surface) with mean ulcer floor (posterior epithelium) heights of 190, 150, 25, 10, and 10 μm, respectively, compared to 200 μm in non-irradiated animals. The mean RIOM ulcer size % of the total epithelialized upper surface of the animal tongue was RT dose dependent. At day 10, the ulcer size % was 2, 5, 27, and 31% for 15, 18, 20, and 25 Gy RT, respectively. The mean relative surface area of the total epithelialized upper surface of the tongue was RT dose dependent, since it was significantly decreased to 97, 95, 88, and 38% with 15, 18, 20, and 25 Gy doses, respectively, at day 10 after RT. Subcutaneous injection of 1 mL of 0.9% saline/6 h for 24 h yielded a 100% survival only with 18 Gy self-resolved RIOM, which had 5.6 ± 0.3 days ulcer duration. In conclusion, we have generated a 100% survival self-resolved single-dose RIOM male mouse model with long enough duration for application in RIOM management research. Oral mucositis ulceration was radiation dose dependent. Sufficient hydration of animals after radiation exposure significantly improved their survival.

Histopathologic grading of oral mucositis

OBJECTIVE

Oral mucositis is a common adverse effect of cytotoxic chemotherapy and radiation, and it causes debilitating morbidity that may necessitate interruptions in cancer treatment. Animal models of oral mucositis are invaluable tools for testing novel therapeutics, but grading of lesions based on subjective assessments makes conformism between studies difficult. A standardized scoring system that can objectively and reproducibly grade the severity of oral mucositis is critical in comparing and validating efficacies of developing therapeutics.

MATERIALS AND METHODS

The head region of male Balb/C animals was exposed to collimated radiation delivered as fractions of 8 Gy on three consecutive days, or as a single large dose of 22.5 Gy. The development of oral toxicity was assessed by histologic analysis of the tongue at various days postradiation.

RESULTS

After fractionated radiation, early epithelial atypia of basal cell layer disorganization and nuclear aberrations was evident by day 6. The disease displayed moderate changes of epithelial atrophy and dyskeratosis by day 7.5 with subsequent epithelial breakdown and ulceration by day 9. In contrast, exposure to a single large-dose radiation resulted in bulla formation by day 9 in most animals.

CONCLUSIONS

An oral mucositis grading system based on histopathologic scoring of tissues is proposed.

A prospective study to assess in vivo optical coherence tomography imaging for early detection of chemotherapy-induced oral mucositis

BACKGROUND AND OBJECTIVE

Oral mucositis (OM) is a common and severe complication of many cancer therapies. Currently, prediction and early detection are not possible and objective monitoring remains problematic. Goal of this prospective study is to assess non-invasive imaging using optical coherence tomography (OCT) for early detection and evaluation of chemotherapy-induced OM in 48 patients, 12 of whom developed clinical mucositis.

STUDY DESIGN/MATERIALS AND METHODS

In 48 patients receiving neoadjuvant chemotherapy for primary breast cancer, oral mucosal health was assessed clinically, and imaged using non-invasive OCT. Images were evaluated for mucositis using an imaging-based scoring system ranging from 0 to 6. Conventional clinical assessment using the OM assessment scale (OMAS) was used as the gold standard. Patients were evaluated on Days 0-11 after commencement of chemotherapy. OCT images were visually scored by three blinded investigators.

RESULTS

The following events were identified from OCT images (1) change in epithelial thickness and subepithelial tissue integrity (beginning on Day 2), (2) loss of surface keratinized layer continuity (beginning on Day 4), (3) loss of epithelial integrity (beginning on Day 4). Imaging data gave higher scores compared to clinical scores early in treatment, suggesting that the imaging-based diagnostic scoring was more sensitive to early mucositic change than the clinical scoring system. Once mucositis was established, imaging and clinical scores converged.

CONCLUSION

Using OCT imaging and a novel scoring system, earlier, more sensitive detection of mucositis was possible than using OMAS. Specific imaging-based changes were a consistent predictor of clinical mucositis.

An imaging-based approach to the evaluation of xerostomia

BACKGROUND AND OBJECTIVE

Goal was to evaluate the potential of in vivo optical coherence tomography (OCT) imaging to determine the response of patients with xerostomia to a dry mouth toothpaste versus fluoride toothpaste placebo.

STUDY DESIGN/MATERIALS AND METHODS

Ten subjects with xerostomia participated in this double-blind, crossover, placebo-controlled study. After examination and OCT imaging, subjects used the first product for 15 days, followed by a 7-day washout period, and then they used the second product for 15 days. Data were acquired at 5-day intervals, also before and after the washout.

RESULTS

Visual examination and tongue blade adhesion test did not reflect response to the product. Two imaging-based markers were identified: (i) In OCT images, epithelial thickness increased significantly (P < 0.05) after use of the dry mouth toothpaste, but did not change significantly (P > 0.05) after the use of a fluoride toothpaste and (2) Optical backscattering data showed progressive characteristic changes from baseline with use of the active product.

CONCLUSIONS

In this pilot study using in vivo OCT imaging, it was possible to detect and measure oral epithelial response to the dry mouth product versus placebo in patients with xerostomia.

CLINICAL IMPLICATIONS

This approach may permit site-specific assessment of xerostomia, individualized treatment planning and monitoring, and sequential mucosal mapping in patients with dry mouth.

Noninvasive in vivo structural and vascular imaging of human oral tissues with spectral domain optical coherence tomography

A spectral domain optical coherence tomography (SD-OCT) system and an oral imaging probe have been developed to visualize the microstructural morphology and microvasculature in the human oral cavity. Structural OCT images of ex vivo pig oral tissues with the histology of the same sites were acquired and compared for correlations. Structural in vivo OCT images of healthy human tissue as well as a pathologic site (ulcer) were obtained and analyzed based on the results of the ex vivo pig study, drawing on the similarity between human and swine oral tissues. In vivo Doppler and speckle variance OCT images of the oral cavity in human volunteers were also acquired, to demonstrate the feasibility of microvascular imaging of healthy and pathologic (scar) oral tissue.

Application of optical imaging and spectroscopy to radiation biology

Optical imaging and spectroscopy is a diverse field that has been of critical importance in a wide range of areas in radiation research. It is capable of spanning a wide range of spatial and temporal scales, and has the sensitivity and specificity needed for molecular and functional imaging. This review will describe the basic principles of optical imaging and spectroscopy, highlighting a few relevant applications to radiation research.

[Optical coherence tomography in otolaryngology]

Optical coherence tomography is an imaging technique based on coherence interferometry. It is used in many medical fields due to its non-invasive imaging capabilities with micrometer resolution. The aim of the authors was to review the applicability of the optical coherence tomography in otolaryngology. Literature data and their own studies show that optical coherence tomography is a reliable method for identifying and targeted biopsy of inflammated, pre-malignant or cancer tissue in human laryngeal and pharyngeal mucosa. Another emerging field for optical coherence tomography is diagnosis of middle ear diseases, especially stapes ankylosis and cholesteatoma.

Prevention of radiation-induced salivary hypofunction following hKGF gene delivery to murine submandibular glands

PURPOSE

Salivary glands are significantly affected when head and neck cancer patients are treated by radiation. We evaluated the effect of human keratinocyte growth factor (hKGF) gene transfer to murine salivary glands on the prevention of radiation-induced salivary hypofunction.

EXPERIMENTAL DESIGN

A hybrid serotype 5 adenoviral vector encoding hKGF (AdLTR(2)EF1α-hKGF) was constructed. Female C3H mice, 8 weeks old, were irradiated by single (15 Gy) or fractionated (6 Gy for 5 days) doses to induce salivary hypofunction. AdLTR(2)EF1α-hKGF or AdControl was administered (10(8) - 10(10) particles per gland) to both submandibular glands (SG) by retrograde ductal instillation before irradiation (IR). Salivary flow was measured following pilocarpine stimulation. Human KGF levels were measured by ELISA. SG cell proliferation was measured with bromodeoxyuridine labeling. Endothelial and progenitor or stem cells in SGs were measured by flow cytometry. The effect of SG hKGF production on squamous cell carcinoma (SCC VII) tumor growth was assessed.

RESULTS

In 3 separate single-dose IR experiments, salivary flow rates of mice administered the AdLTR(2)EF1α-hKGF vector were not significantly different from nonirradiated control mice (P > 0.05). Similarly, in 3 separate fractionated IR experiments, the hKGF-expressing vector prevented salivary hypofunction dramatically. Transgenic hKGF protein was found at high levels in serum and SG extracts. AdLTR(2)EF1α-hKGF-treated mice showed increased cell proliferation and numbers of endothelial cells, compared with mice treated with AdControl. hKGF gene transfer had no effect on SCC VII tumor growth ± radiation.

CONCLUSIONS

hKGF gene transfer prevents salivary hypofunction caused by either single or fractionated radiation dosing in mice. The findings suggest a potential clinical application.

Optical diagnostics in the oral cavity: an overview

As the emphasis shifts from damage mitigation to disease prevention or reversal of early disease in the oral cavity, the need for sensitive and accurate detection and diagnostic tools become more important. Many novel and emergent optical diagnostic modalities for the oral cavity are becoming available to clinicians with a variety of desirable attributes including: (i) non-invasiveness, (ii) absence of ionizing radiation, (iii) patient-friendliness, (iv) real-time information (v) repeatability, and (vi) high-resolution surface and subsurface images. In this article, the principles behind optical diagnostic approaches, their feasibility and applicability for imaging soft and hard tissues, and their potential usefulness as a tool in the diagnosis of oral mucosal lesions, dental pathologies, and other dental applications will be reviewed. The clinical applications of light-based imaging technologies in the oral cavity and of their derivative devices will be discussed to provide the reader with a comprehensive understanding of emergent diagnostic modalities.

Diagnosis of oral submucous fibrosis with optical coherence tomography

The epithelium (EP) thickness and the standard deviation (SD) of A-mode scan intensity in the laminar propria (LP) layer are used as effective indicators for the diagnosis of oral submucous fibrosis (OSF) based on the noninvasive clinical scanning of a swept-source optical coherence tomography (OCT) system of approximately 6 mum in axial resolution (in tissue) and 103 dB in sensitivity. Compared with the corresponding parameters in healthy oral mucosal mucosa, in OSF mucosa, the EP thickness becomes smaller and the SD of A-mode scan intensity in the LP layer (LP SD) also becomes smaller. The LP SD can also be used for effectively differentiating OSF (small LP SD) from lesion (large LP SD). This application is particularly useful in the case of a lesion without a clear surface feature. Meanwhile, the use of the SD of A-mode scan intensity in the EP layer (EP SD) can further help in differentiating OSF (medium EP SD) from healthy oral mucosal (small EP SD) and lesion (large EP SD) conditions. Compared with the conventional method of maximum mouth opening measurement, the use of the proposed OCT scanning results can be a more effective technique for OSF diagnosis.

Prevention of radiation-induced oral mucositis after adenoviral vector-mediated transfer of the keratinocyte growth factor cDNA to mouse submandibular glands

PURPOSE

The study aims to evaluate if human keratinocyte growth factor (hKGF), secreted after transduction of murine salivary glands with adenoviral vectors, can prevent oral mucositis resulting from radiation.

EXPERIMENTAL DESIGN

Two serotype 5 adenoviral vectors encoding hKGF were constructed: AdEF1alpha-hKGF and AdLTR(2)EF1alpha-hKGF. Female C3H mice, 8 weeks old, were irradiated by single (22.5 Gy) or fractionated (5 x 8 Gy for 5 days) doses to induce oral mucositis (ulcers on tongue). One day before irradiation, the above viral vectors or an empty vector, Adcontrol, was given (10(10) particles per gland) to both submandibular glands by retrograde ductal instillation. Each experiment included five groups: no irradiation and irradiation (+/-Adcontrol, AdEF1alpha-hKGF, or AdLTR(2)EF1alpha-hKGF). Blood, saliva, submandibular glands, and tongue were collected on day 7 for single-dose studies or day 10 for fractionated dosing. hKGF levels were measured by ELISA.

RESULTS

In three separate single-dose irradiation experiments, lingual ulcers were dramatically reduced after either KGF-expressing vector. Similarly, in two separate fractionated irradiation experiments, the hKGF-expressing vectors completely prevented ulcer formation. QPCR data indicated that approximately 10(7) to 10(8) particles of each vector remained in the targeted submandibular glands at the terminal time. Transgenic hKGF protein was found at high levels in saliva, serum, and submandibular gland extracts.

CONCLUSIONS

hKGF gene transfer to salivary glands prevented radiation-induced oral mucositis in mice. This proof of concept study suggests that transgenic hKGF secreted from transduced salivary glands may be useful clinically to prevent oral mucositis caused by radiation.

Differentiating oral lesions in different carcinogenesis stages with optical coherence tomography

A swept-source optical coherence tomography (SS-OCT) system is used to clinically scan oral lesions in different oral carcinogenesis stages, including normal oral mucosa control, mild dysplasia (MiD), moderate dysplasia (MoD), early-stage squamous cell carcinoma (ES-SCC), and well-developed SCC (WD-SCC), for diagnosis purpose. On the basis of the analyses of the SS-OCT images, the stages of dysplasia (MiD and MoD), and SCC (ES-SCC and WD-SCC) can be differentiated from normal control by evaluating the depth-dependent standard deviation (SD) values of lateral variations. In the dysplasia stage, the boundary between the epithelium (EP) and lamina propria (LP) layers can still be identified and the EP layer becomes significantly thicker than that of normal control. Also, in a certain range of the EP layer above the EP/LP boundary, the SD value becomes larger than a certain percentage of the maximum level, which is observed around the EP/LP boundary. On the other hand, in the ES-SCC and WD-SCC stages, the EP/LP boundary disappears. Because of the higher density of connective tissue papillae in the ES-SCC stage, the SD values of the slowly varying lateral scan profiles in the ES-SCC samples are significantly larger than those in the WD-SCC sample. Also, ES-SCC can be differentiated from WD-SCC by comparing the exponential decay constants of averaged A-mode scan profiles. Because of the higher tissue absorption in the WD-SCC lesion, the decay constants in the WD-SCC samples are significantly higher than those in the ES-SCC samples.

R-Spondin1 protects mice from chemotherapy or radiation-induced oral mucositis through the canonical Wnt/beta-catenin pathway

R-Spondin1 (RSpo1) is a novel secreted protein that augments canonical Wnt/beta-catenin signaling. We injected recombinant RSpo1 protein into transgenic Wnt reporter TOPGAL mice and have identified the oral mucosa as a target tissue for RSpo1. Administration of RSpo1 into normal mice triggered nuclear translocation of beta-catenin and resulted in increased basal layer cellularity, thickened mucosa, and elevated epithelial cell proliferation in tongue. We herein evaluated the therapeutic potential of RSpo1 in treating chemotherapy or radiotherapy-induced oral mucositis in several mouse models. Prophylactic treatment with RSpo1 dose-dependently overcame the reduction of basal layer epithelial cellularity, mucosal thickness, and epithelial cell proliferation in tongues of mice exposed to whole-body irradiation. RSpo1 administration also substantially alleviated tongue mucositis in the oral cavity of mice receiving concomitant 5-fluorouracil and x-ray radiation. Furthermore, RSpo1 significantly reduced the extent of tongue ulceration in mice receiving a single fraction, high dose head-only radiation in a dose-dependent manner. Moreover, combined therapy of RSpo1 and keratinocyte growth factor resulted in complete healing of tongue ulcers in mice subjected to snout-only irradiation. In conclusion, our results demonstrate RSpo1 to be a potent therapeutic agent for oral mucositis by enhancing basal layer epithelial regeneration and accelerating mucosal repair through up-regulation of Wnt/beta-catenin pathway.

Effective indicators for diagnosis of oral cancer using optical coherence tomography

A swept-source optical coherence tomography system is used to clinically scan oral precancer and cancer patients for statistically analyzing the effective indicators of diagnosis. Three indicators are considered, including the standard deviation (SD) of an A-mode scan signal profile, the exponential decay constant (alpha) of an A-mode-scan spatial-frequency spectrum, and the epithelium thickness (T) when the boundary between epithelium and lamina propria can still be identified. Generally, in abnormal mucosa, the standard deviation becomes larger, the decay constant of the spatial-frequency spectrum becomes smaller, and epithelium becomes thicker. The sensitivity and specificity of the three indicators are discussed based on universal and individual relative criteria. It is found that SD and alpha are good diagnosis indicators for moderate dysplasia and squamous cell carcinoma. On the other hand, T is a good diagnosis indicator for epithelia hyperplasia and moderate dysplasia.

Delineation of an oral cancer lesion with swept-source optical coherence tomography

We demonstrate the ex vivo imaging of an oral cancerous sample with a swept-source optical coherence tomography (SS-OCT) system. With the axial resolution of 8 microm in free space and system sensitivity of 108 dB, we can well distinguish the normal and abnormal tissue portions in a sample. In particular, we analyze the lateral variation of A-scan profiles to show two parameters of SS-OCT signal for delineating an oral cancer lesion. One of the parameters is the decay constant in the exponential fitting of the SS-OCT signal intensity along depth. This decay constant decreases as the A-scan point moves laterally across the margin of a lesion. The other parameter is the standard deviation of the SS-OCT signal intensity fluctuation in an A-scan. This parameter increases significantly when the A-scan point is moved across the transition region between the normal and abnormal portions. Such parameters are useful for determining the margins of oral cancer.

In vivo optical coherence tomography-based scoring of oral mucositis in human subjects: a pilot study

A preliminary study to assess noninvasive optical coherence tomography (OCT) for early detection and evaluation of chemotherapy-induced oral mucositis in five patients. In five patients receiving neoadjuvant chemotherapy for primary breast cancer, oral mucositis was assessed clinically, and imaged using noninvasive OCT. Imaging was scored using a novel imaging-based scoring system. Conventional clinical assessment using the Oral Mucositis Assessment Scale was used as the gold standard. Patients were evaluated on days 0, 2, 4, 7, and 11 after commencement of chemotherapy. OCT images were visually examined by one blinded investigator. The following events were identified using OCT: (1) change in epithelial thickness and subepithelial tissue integrity (beginning on day 2), (2) loss of surface keratinized layer continuity (beginning on day 4), (3) loss of epithelial integrity (beginning on day 4). Imaging data gave higher scores compared to clinical scores earlier in treatment, suggesting that the imaging-based diagnostic scoring was more sensitive to early mucositic change than the clinical scoring system. Once mucositis was established, imaging and clinical scores converged. Chemotherapy-induced oral changes were identified prior to their clinical manifestation using OCT, and the proposed scoring system for oral mucositis was validated for the semiquantification of mucositic change.

Clinical diagnosis of potentially treatable early articular cartilage degeneration using optical coherence tomography

A series of bench to operating room studies was conducted to determine whether it is feasible to use optical coherence tomography (OCT) clinically to diagnose potentially reversible early cartilage degeneration. A human cadaver study was performed to confirm the reproducibility of OCT imaging and grading based on identification of changes to cartilage OCT form birefringence using a polarized OCT system approved for clinical use. Segregation of grossly normal appearing human articular cartilage into two groups based on the presence or absence of OCT form birefringence showed that cartilage without OCT form birefringence had reduced ability to increase proteoglycan synthetic activity in response to the anabolic growth factor IGF-1. The bench data further show that IGF-1 insensitivity in cartilage without OCT form birefringence was reversible. To show clinical feasibility, OCT was then used arthroscopically in 19 human subjects. Clinical results confirmed that differences to OCT form birefringence observed in ex vivo study were detectable during arthroscopic surgery. More prevalent loss of cartilage OCT form birefringence was observed in cartilage of human subjects in groups more likely to have cartilage degeneration. This series of integrated bench to bedside studies demonstrates translational feasibility to use OCT for clinical studies on whether human cartilage degeneration can be diagnosed early enough for intervention that may delay or prevent the onset of osteoarthritis.

In vivo Imaging of Oral Mucositis in an Animal Model Using Optical Coherence Tomography and Optical Doppler Tomography

PURPOSE

To assess noninvasive optical coherence tomography (OCT) and optical Doppler tomography (ODT) for early detection and evaluation of chemotherapy-induced oral mucositis.

EXPERIMENTAL DESIGN

Cheek pouches of 10 Syrian golden hamsters were imaged using OCT/ODT during development of chemotherapy-induced mucositis. I.p. injections of 5-fluorouracil and mechanical irritation induced oral lesions. At 2, 4, 7, and 11 days, one hamster was sacrificed and processed for histopathology. OCT images were visually examined; ODT results were semiquantified. Imaging data were compared with histologic findings.

RESULTS

During the development of mucositis, OCT/ODT identified the following events: (a) change in epithelial thickness (beginning on day 2), (b) loss of surface keratinized layer continuity (beginning on day 4), (c) loss of epithelial (day 4 onwards) and submucosal integrity (day 7 onwards), (d) changes in axial blood flow velocity (increased on days 2 and 4; decreased on day 7), and (e) changes in blood vessel size (diameter doubled on day 2; quadrupled on day 4; unchanged on day 7). The semiquantitative imaging-based scoring system identified the severity of mucositis as defined by histopathology. The combination of imaging criteria used allowed for the detection of early, intermediate, and late mucositic changes. Imaging data gave higher scores compared with clinical scores early on, suggesting that the imaging-based diagnostic scoring was more sensitive to early mucositic change than the clinical scoring system. Once mucositis was established, imaging and clinical scores converged.

CONCLUSION

OCT/ODT identified chemotherapy-induced oral changes before their clinical manifestation, and the proposed scoring system for oral mucositis was validated for the semiquantification of mucositic change.