Early inflammatory changes in radiation-induced oral mucositis : Effect of pentoxifylline in a mouse model

Cytokine Levels in Saliva Are Associated with Salivary Gland Fibrosis and Hyposalivation in Mice after Fractionated Radiotherapy of the Head and Neck

Cytokines are mediators of inflammation that could lead to fibrosis. The aim was to monitor cytokine levels in saliva and serum after locally fractionated radiotherapy of the head and neck in mice and investigate associations with salivary gland fibrosis and hyposalivation. C57BL/6 mice were randomized to sham or X-ray irradiation of 66 Gy in 10 fractions over 5 days. Blood and saliva were collected on days -7, 5, 35, 80, and 105 following cytokine analysis. The harvested submandibular salivary gland was assessed for the presence of fibrosis. Decision tree regression analysis was used to investigate whether cytokine levels could predict late endpoints in terms of hyposalivation or fibrosis. Significant formation of fibrosis in gland tissue and reduced saliva production was found after irradiation. The pro-inflammatory cytokines IL-1α, TNF, TIMP1, G-CSF, KC, and MIP-1α showed increased levels in saliva in irradiated mice and a strong correlation with late endpoints. The decision tree analysis largely separated controls from irradiated animals, with IL-1α being the strongest predictor. Pro-inflammatory cytokines in saliva, but not in serum, were associated with late endpoints. This indicates that cytokine expression in saliva is a good biomarker for local salivary gland damage with IL-1α as the strongest single predictor.

Rodent models for anticancer toxicity studies: contributions to drug development and future perspectives

Antineoplastic treatment induces a type of gastrointestinal toxicity known as mucositis. Findings in animal models are usually easily reproducible, and standardized treatment regimens are often used, thus supporting translational science. Essential characteristics of mucositis, including intestinal permeability, inflammation, immune and oxidative responses, and tissue repair mechanisms, can be easily investigated in these models. Given the effects of mucositis on the quality of life of patients with cancer, and the importance of experimental models in the development of more effective new therapeutic alternatives, this review discusses progress and current challenges in using experimental models of mucositis in translational pharmacology research. Teaser Experimental models for studying gastrointestinal mucositis have provided a wealth of information improving the understanding of antineoplastic toxicity.

Identification of potential molecular mechanisms and candidate drugs for radiotherapy- and chemotherapy-induced mucositis

BACKGROUND

Radiotherapy-induced oral mucositis (RIOM) and chemotherapy-induced oral mucositis (CIOM) are common complications in cancer patients, leading to negative clinical manifestations, reduced quality of life, and unsatisfactory treatment outcomes.

OBJECTIVE

The present study aimed to identify potential molecular mechanisms and candidate drugs by data mining.

METHODS

We obtained a preliminary list of genes associated with RIOM and CIOM. In-depth information on these genes was explored by functional and enrichment analyses. Then, the drug-gene interaction database was used to determine the interaction of the final enriched gene list with known drugs and analyze the drug candidates.

RESULTS AND CONCLUSION

This study identified 21 hub genes that may play an important role in RIOM and CIOM, respectively. Through our data mining, bioinformatics survey, and candidate drug selection, TNF, IL-6, and TLR9 could play an important role in disease progression and treatment. In addition, eight candidate drugs (olokizumab, chloroquine, hydroxychloroquine, adalimumab, etanercept, golimumab, infliximab, and thalidomide) were selected by the drug-gene interaction literature search additionally, as candidates for treating RIOM and CIOM.

Prophylactic management of radiation-induced mucositis using herbal mouthwash in patients with head and neck cancer: an assessor-blinded randomized controlled trial

OBJECTIVES

Radiation-induced mucositis (RIOM) is one of the most common side effects from head and neck radiotherapy. Several reagents have been introduced to manage the symptom; however, there is still a limited number of effective reagents. Herbal mouthwashes with payayor (Clinacanthus nutans Lindau) and fingerroot (Boesenbergia rotunda) were tested their efficacies in preventing and reducing severity of RIOM in comparison with normal saline with sodium bicarbonate.

METHODS

One hundred twenty patients with head and neck cancer undergoing radiotherapy participated in the study and were randomly assigned into three treatment groups using block randomization method. The participants were assigned one of the three mouthwashes for use throughout their radiotherapy course and were assessed for their mucositis scores from week one to six into their radiotherapy course as well as at one-month follow-up. Body mass index was also measured for comparison of nutritional status.

RESULTS

The two mouthwashes were similarly effective in prophylaxis of RIOM in term of severity. The averaged mucositis scores were less than two for all groups. For the onset of RIOM, both herbal mouthwashes could slightly delay the symptom but not statistically significant. Patients' body mass index across the three treatment groups was also comparable. The patients were largely satisfied with all the mouthwashes with no clear preference on any of them.

CONCLUSIONS

Prophylactic treatment of RIOM using herbal mouthwashes could substitute the current standard of normal saline with bicarbonate. A different formulation of the two herbs could potentially improve the prophylactic outcome.

TRIAL REGISTRATION NO

NCT03359187.

Construction of a predictive model for radiation proctitis after radiotherapy for female pelvic tumors based on machine learning

OBJECTIVES

Radiation therapy is a main method for female pelvic malignancies, which can cause some adverse reactions, such as radiation proctitis (RP). The incidence of RP is highly positively correlated with radiation dose. There is an urgent need for a scientific method to accurately predict the occurrence of RP to help doctors make clinical decisions. In this study, based on the clinical data of female pelvic tumor patients and dosimetric parameters of radiotherapy, the random forest method was used to screen the hub features related to the occurrence of RP, and then a machine learning algorithm was used to construct a risk prediction model for the occurrence of RP, in order to provide technical support and theoretical basis for the prediction and prevention of RP.

METHODS

A total of 100 female patients with pelvic tumors, who received static three-dimensional conformal intensity-modulated radiation therapy in the Department of Radiation Oncology of the Affiliated Hospital of Xiangnan University from January 2019 to December 2020, were retrospectively collected, and their clinically relevant data and radiotherapy planning system data were collected. During radiotherapy and 18 months after radiotherapy, 35 cases developed RP (RP group), and the remaining 65 cases had no RP (non-RP group). The clinical and dosimetric characteristics of patients were ranked by the importance of random forest algorithm, and the independent prognostic characteristics associated with the occurrence of RP were selected for machine learning modeling. A total of 6 machine learning algorithms including support vector machines, random forests, logistic regression, lightweight gradient boosting machines, Gaussian naïve Bayes, and adaptive enhancement were used to build models. The performance of the model was evaluated by the area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and F1 score. Finally, the random forest model was determined as the prediction model, and the calibration curve and decision curve of the prediction model were drawn to evaluate the accuracy and clinical benefit of the model.

RESULTS

The parameters for random forest prediction model in the training set were as follow: AUC, 1.000, accuracy, 0.988, sensitivity, 1.000, specificity, 1.000, positive predictive value, 1.000, negative predictive value, 0.981, and F1 score, 1.000. In validation set, AUC was 0.713, accuracy was 0.640, sensitivity was 0.618, specificity was 0.822, positive predictive value was 0.500, negative predictive value was 0.656, and F1 score was 0.440. Random forest showed high predictive performance. Moreover, the Brief of the calibration curve for the prediction model was 0.178, the prediction accuracy was high, and the decision curve showed that the prediction model could benefit clinically.

CONCLUSIONS

Based on the clinical and dosimetric parameters for the female pelvic tumor patients, the prediction model of radiation proctitis constructed by random forest algorithm has high predictive ability and strong clinical usability.

The Interplay among Radiation Therapy, Antibiotics and the Microbiota: Impact on Cancer Treatment Outcomes

Radiation therapy has been used for more than a century, either alone or in combination with other therapeutic modalities, to treat most types of cancer. On average, radiation therapy is included in the treatment plans for over 50% of all cancer patients, and it is estimated to contribute to about 40% of curative protocols, a success rate that may reach 90%, or higher, for certain tumor types, particularly on patients diagnosed at early disease stages. A growing body of research provides solid support for the existence of bidirectional interaction between radiation exposure and the human microbiota. Radiation treatment causes quantitative and qualitative changes in the gut microbiota composition, often leading to an increased abundance of potentially hazardous or pathogenic microbes and a concomitant decrease in commensal bacteria. In turn, the resulting dysbiotic microbiota becomes an important contributor to worsen the adverse events caused in patients by the inflammatory process triggered by the radiation treatment and a significant determinant of the radiation therapy anti-tumor effectiveness. Antibiotics, which are frequently included as prophylactic agents in cancer treatment protocols to prevent patient infections, may affect the radiation/microbiota interaction through mechanisms involving both their antimicrobial activity, as a mediator of microbiota imbalances, and their dual capacity to act as pro- or anti-tumorigenic effectors and, consequently, as critical determinants of radiation therapy outcomes. In this scenario, it becomes important to introduce the use of probiotics and/or other agents that may stabilize the healthy microbiota before patients are exposed to radiation. Ultimately, newly developed methodologies may facilitate performing personalized microbiota screenings on patients before radiation therapy as an accurate way to identify which antibiotics may be used, if needed, and to inform the overall treatment planning. This review examines currently available data on these issues from the perspective of improving radiation therapy outcomes.

Extraoral photobiomodulation for prevention of oral and oropharyngeal mucositis in head and neck cancer patients: interim analysis of a randomized, double-blind, clinical trial

Purpose

To assess the safety and efficacy of prophylactic extraoral photobiomodulation (PBM) for the prevention of oral and oropharyngeal mucositis (OM) on clinical outcomes and survival in patients with oral cavity and oropharyngeal squamous cell carcinoma (OOPSCC).

Methods

OOPSCC patients who received radiotherapy (RT) were prospectively randomized to two groups: prophylactic extraoral PBM and placebo. OM grade (NCI), pain (VAS), analgesia, and anti-inflammatory prescriptions were assessed weekly. Quality of life questionnaires (QoL) were performed at the first and last day of RT. Following RT, participants were evaluated quarterly for oncological outcomes follow-up.

Results

Fifty-five patients met the inclusion criteria. The first occurrence of OM was observed at week 1, for the placebo group (p = 0.014). Later, OM onset and severity was observed for the PBM group, with first occurrence at week 2 (p = 0.009). No difference in severe OM incidence was observed (p > 0.05). Lower mean pain score was noted at week 7 for the PBM group (2.1) compared to placebo group (4.5) (p = 0.009). Less analgesics (week 3; p = 0.009/week 7; p = 0.02) and anti-inflammatory prescription (week 5; p = 0.0346) were observed for the PBM group. Better QoL scores were observed for the PBM group at last day of RT (p = 0.0034). No difference in overall survival among groups was observed in 1 year of follow-up (p = 0.889).

Conclusion

Prophylactic extraoral PBM can delay OM onset, reduce pain, and reduce analgesic and anti-inflammatory prescription requirements. Extraoral PBM was associated with better QoL. There was no evidence of PBM impact on oncological outcomes.

Trial registration

TRN:RBR-4w4swx (date of registration: 01/20/2020).

Supplementary Information

The online version contains supplementary material available at 10.1007/s00520-021-06625-8.

Chinese Herbal Medicine to Reduce Radiation-Induced Oral Mucositis in Head and Neck Cancer Patients: Evidence From Population-Based Health Claims

BACKGROUND

Subjects with head and neck cancer (HNC) often experience post-treatment side effects, particularly radiation-induced oral mucositis (RIOM). This study aimed to explore the association of Chinese herbal medicine use with the sequent risk of RIOM among them.

METHODS

This cohort study used a nationwide health insurance database to identify subjects newly diagnosed with HNC, aged 20 to 60 years, who received treatment between 2000 and 2007. Among them, a total of 561 cases received CHM after HNC onset (CHM users); the remaining 2395 cases were non-CHM users. All patients were followed to the end of 2012 to identify any treatment for RIOM as the end point. Cox proportional hazards regression was used to compute the adjusted hazard ratio (aHR) of RIOM by CHM use.

RESULTS

During the follow-up period, 183 CHM users and 989 non-CHM users developed RIOM at incidence rates of 40.98 and 57.91 per 1000 person-years, respectively. CHM users had a lower RIOM risk than the non-CHM users (aHR: 0.68; 95% Confidence Interval: 0.58-0.80). The most potent effect was observed in those taking CHM for more than 1 year. Use of Baizhi, Danshen, Shao-Yao-Gan-Cao-Tang, Gan-Lu-Yin, Huangqin, Shu-Jing-Huo-Xue-Tang, and Xin-Yi-Qing-Fei-Tang, was significantly related to a lower risk of RIOM.

CONCLUSION

Findings of this study indicated that adding CHM to conventional clinical care could be helpful in protecting those with HNC against the onset of RIOM. Further clinical and mechanistic studies are warranted.

Beyond its anti-migraine properties, sumatriptan is an anti-inflammatory agent: A systematic review

Sumatriptan is the first available medication from triptans family that was approved by the U.S. Food and Drug Administration for migraine attacks and cluster headaches in 1991. Most of its action is mediated by selective 5-HT_1B/1D receptor agonism. Recent investigations raised the possibility of repositioning of this drug to other indications beyond migraine, as increasing evidence suggests for an anti-inflammatory property of sumatriptan. We performed a literature search using PubMed, Web of Science, Scopus, and Google Scholar using "inflammation AND sumatriptan" or "inflammation AND 5HT1B/D" as the keywords. Then, articles were screened for their relevance and those directly discussing the correlation between inflammation and sumatriptan or 5HT1B/D were included. Total references reviewed or inclusion/exclusion were 340 retrieved full-text articles (n = 340), then based on critical assessment 66 of them were included in this systematic review. Our literature review indicates that at low doses, sumatriptan can reduce inflammatory markers (e.g., interleukin-1β, tumor necrosis factor-α, and nuclear factor-κB), affects caspases and changes cells lifespan. Additionally, nitric oxide synthase and nitric oxide signaling seem to be regulated by this drug. It also inhibits the release of calcitonin gene-related peptide. Sumatriptan protects against many inflammatory conditions including cardiac and mesenteric ischemia/reperfusion, skin flap, pruritus, peripheral, and central nervous system injuries such as spinal cord injury, testicular torsion-detorsion, oral mucositis, and other experimental models. Considering the safety and potency of low dose sumatriptan compared to corticosteroids and other immunosuppressive medications, it is worth to take advantage of sumatriptan in inflammatory conditions.

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.

Early radiation-induced oral pain signaling responses are reduced with pentoxifylline treatment

Radiation-induced acute oral mucositis is associated with inflammation and pain. In other realms of pain research, nociceptors are known to be activated by inflammatory cytokines; for example, tumor necrosis factor alpha (TNF-α) can activate transient receptor potential ion channels on sensory neurons. But there is an unclear relationship between inflammatory cytokines and molecular mediators of pain in radiation-induced mucositis (RIM) and radiation-associated pain (RAP). In this prospective, analytical, experimental pilot study, a common drug (pentoxifylline [PTX]) was used with the goal of inhibiting TNF-α signaling in mice that underwent lingual irradiation to induce severe acute oral RIM/RAP. Body weight and glossitis scores were recorded daily. Eye wiping behaviors were assayed as a surrogate measure of oral discomfort (which is possible due to cross-sensitization of the mandibular and ophthalmic branches of the trigeminal nerve). Quantitative real-time reverse transcription polymerase chain reaction was performed on irradiated tongue tissue to measure changes in expression of TNF-α, its receptor, nuclear factor kappa-light-chain-enhancer of activated B cells, transient receptor potential vanilloid type 1 (TRPV1), and transient receptor potential vanilloid type 4 (TRPV4). Responsiveness of afferent sensory trigeminal neurons to TNF-α, a TRPV1 agonist (capsaicin), and a partial TRPV4 agonist (histamine) was measured via calcium imaging. Although PTX treatment did not reduce glossitis severity or mitigate weight loss in mice with RIM/RAP, it did inhibit the upregulation of TNF-α's receptor that normally accompanies RIM, and it also reduced neuronal responsiveness to each of the aforementioned chemical stimuli. These results provide provisional evidence that inhibition of TNF-α signaling with PTX treatment may serve as a useful tool for reducing pain in head and neck cancer patients.

Modulation of radiation-induced oral mucositis (mouse) by dermatan sulfate: effects on differentiation processes

PURPOSE

During head and neck cancer radiotherapy, oral mucositis is the most frequent early side effect. Systemic dermatan sulfate (DS) administration has been shown to significantly decrease oral mucosal radiation reactions during daily fractionated irradiation (IR) in an established mouse model. The aim of this study was to investigate the mechanism of the oral epithelial differentiation process, during IR alone and in combination with DS treatment in the same mouse model.

METHODS

Fractionated IR 5 × 3 Gy/week was given to the snouts of mice over two weeks, either alone (IR) or in combination with daily DS treatment of 4 mg/kg (IR + DS). Groups of mice (n = 3) were sacrificed every second day over the course of 14 days in both experimental arms. Their tongue was excised and subjected to immunohistochemical processing.

RESULTS

In the p16 analysis as a proliferation marker, the difference between IR alone and IR + DS in the germinal (proliferation) layer was not significant, not stimulating the proliferation process. For the p21 analysis as a differentiation marker on the functional (differentiation) layer, the difference between IR alone and IR + DS arms was significant, indicating that DS inhibited the differentiation process. In the cytokeratin (CK) analysis as the indicator of cellular skeletal integrity, the percentage of antibody-positive cells was above the normal level in both experimental arms and significantly superior in the IR + DS arm.

CONCLUSION

The mucosal protective activity of DS, instead of stimulating proliferation, is based on prevention of cell loss by a combination of effects leading to the inhibition of cellular differentiation and an increase in the expression of epithelial mechanical strength between intercellular mechanical junctions.

Promising role of filgrastim and α-tocopherol succinate in amelioration of gastrointestinal acute radiation syndrome (GI-ARS) in mice

The protective role of α-tocopherol succinate (α-TCS) and the therapeutic efficacy of filgrastim were investigated in gastrointestinal acute radiation syndrome (GI-ARS) induced following 10 Gy whole-body γ-irradiation. Mice were randomly allocated into 5 groups: [1] normal-control, [2] irradiated-control, [3] subcutaneous (s.c.) injection of filgrastim (5 μg/kg/day) for 4 consecutive days given 1 h post-irradiation, [4] s.c. injection with α-TCS (400 mg/kg) 1 day prior to irradiation, [5] s.c. injection with α-TCS (400 mg/kg) 1 day prior to irradiation and filgrastim (5 μg/kg/day) for 4 consecutive days 1 h post-irradiation. Histopathological analysis, serum citrulline level, intestinal interleukin-1β (IL-1β), reduced glutathione (GSH), and malondialdehyde (MDA) contents as well as myeloperoxidase (MPO) activity were measured. Intestinal caspase-3, p53, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) immunopositivity were examined. In irradiated-control, MDA increased (249%) and GSH decreased (25%) compared to normal and were unaffected by filgrastim. α-TCS alone significantly reduced MDA (84.5%) and normalized GSH. The combination significantly reduced MDA (59%) and dramatically increased GSH (1573%), pointing to a possible synergistic action. In irradiated-control, MPO and IL-1β significantly increased (111% and 613%, respectively) compared to normal-control and both were significantly decreased in all treated groups. Compared to normal-control, citrulline significantly declined (68%) in irradiated-control; a significant elevation was achieved by treatments with α-TCS alone or combined with filgrastim (88% and 94%, respectively). The combination therapy significantly decreased the degree of irradiation-induced injury of the epithelium and cellular infiltration and showed the lowest histopathological scoring compared to the other groups (p ≤ 0.05). In irradiated-control, immune-reactive expressions of iNOS, COX-2, caspase-3, and p53 were remarkable (18.62%, 34.27%, 31.19%, and 27.44%, respectively) and after combination therapy were reduced (1.04%, 22.39%, 8.76%, and 4.91%, respectively). The current findings represent a first-hand strategy in dealing with GI-ARS with a potential preference to using a combined therapy of filgrastim and α-TCS.

Effects of a compound vitamin B mixture in combination with GeneTime® on radiation-induced oral mucositis

Objective

Both compound vitamin B mixtures and GeneTime® have been used in treatment of oral inflammation. This study aimed to assess the therapeutic effects of a compound vitamin B mixture combined with GeneTime® on radiation-induced oral mucositis.

Methods

A total of 100 patients with radiation-induced oral mucositis were randomly divided into a control group (vitamin B alone; n = 50 patients) and an observation group (vitamin B plus GeneTime®, n = 50 patients). Clinical outcomes were compared between the two groups for the following 3 weeks.

Results

The observation group had a significantly greater number of grade 0–I patients and significantly fewer grade II–IV patients than the control group. Among patients in the observation group, a significantly greater number of ulcers healed within 1–2 weeks, compared with those in patients in the control group. Significantly fewer ulcers healed among patients in the observation group at 3 weeks; notably, there were fewer ulcers to heal in the observation group, compared with the control group.

Conclusions

Use of a compound vitamin B mixture combined with GeneTime® exerted obvious therapeutic effects on radiation-induced oral mucositis and markedly shortened ulcer healing time. Therefore, this strategy may be useful in clinical applications.

Protective effects of systemic dermatan sulfate treatment in a preclinical model of radiation-induced oral mucositis

PURPOSE

Oral mucositis is a frequent, dose-limiting side effect of radio(chemo)therapy of head-and-neck malignancies. The epithelial radiation response is based on multiple tissue changes, which could offer targets for a biologically tailored treatment. The potential of dermatan sulfate (DS) to modulate radiation-induced oral mucositis was tested in an established preclinical mucositis model.

METHODS

Irradiation was either applied alone or in combination with daily DS treatment (4 mg/kg, subcutaneously) over varying time intervals. Irradiation comprised single dose irradiation with graded doses to the lower tongue surface or daily fractionated irradiation of the whole tongue. Fractionation protocols (5 × 3 Gy/week) over one (days 0-4) or two weeks (days 0-4, 7-11) were terminated by an additional local single dose irradiation to a defined treatment field on the lower tongue surface to induce the mucosal radiation response. The additional single dose irradiation (top-up) on day 7 (after one week of fractionation) or day 14 (after 2 weeks of fractionation) comprised graded doses in order to generate full dose-effect curves. Ulceration of the epithelium of the lower tongue, corresponding to confluent mucositis, was analysed as clinically relevant endpoint. Additionally, the time course parameters, latent time and ulcer duration were analysed.

RESULTS

DS treatment significantly reduced the incidence of ulcerations. DS application over longer time intervals resulted in a more pronounced reduction of ulcer frequency, increased latent times and reduced ulcer duration.

CONCLUSION

DS has a significant mucositis-ameliorating activity with pronounced effects on mucositis frequency as well as on time course parameters.

Radioprotective Effects of Dermatan Sulfate in a Preclinical Model of Oral Mucositis-Targeting Inflammation, Hypoxia and Junction Proteins without Stimulating Proliferation

Oral mucositis is the most frequently occurring early side effect of head-and-neck cancer radiotherapy. Systemic dermatan sulfate (DS) treatment revealed a significant radioprotective potential in a preclinical model of oral mucositis. This study was initiated to elucidate the mechanistic effects of DS in the same model. Irradiation comprised daily fractionated irradiation (5 × 3 Gy/week) over two weeks, either alone (IR) or in combination with daily dermatan sulfate treatment of 4 mg/kg (IR + DS). Groups of mice (n = 5) were sacrificed every second day over the course of 14 days in both experimental arms, their tongues excised and evaluated. The response to irradiation with and without DS was analyzed on a morphological (cell numbers, epithelial thickness) as well as on a functional (proliferation and expression of inflammation, hypoxia and epithelial junction markers) level. The mucoprotective activity of DS can be attributed to a combination of various effects, comprising increased expression of epithelial junctions, reduced inflammation and reduced hypoxia. No DS-mediated effect on proliferation was observed. DS demonstrated a significant mucositis-ameliorating activity and could provide a promising strategy for mucositis treatment, based on targeting specific, radiation-induced, mucositis-associated signaling without stimulating proliferation.

Challenges in the local delivery of peptides and proteins for oral mucositis management

Oral mucositis, a common inflammatory side effect of oncological treatments, is a disorder of the oral mucosa that can cause painful ulcerations, local motor disabilities, and an increased risk of infections. Due to the discomfort it produces and the associated health risks, it can lead to cancer treatment restrains, such as the need for dose reduction, cycle delays or abandonment. Current mucositis management has low efficiency in prevention and treatment. A topical drug application for a local action can be a more effective approach than systemic routes when addressing oral cavity pathologies. Local delivery of growth factors, antibodies, and anti-inflammatory cytokines have shown promising results. However, due to the peptide and protein nature of these novel agents, and the several anatomic, physiological and environmental challenges of the oral cavity, their local action might be limited when using traditional delivering systems. This review is an awareness of the issues and strategies in the local delivery of macromolecules for the management of oral mucositis.

Upregulated epithelial junction expression represents a novel parameter of the epithelial radiation response to fractionated irradiation in oral mucosa

Purpose

During head and neck cancer treatment, the radiation response of the oral mucosa represents a frequent early side effect. Besides radiation-induced inhibition of proliferation, various other cellular responses occur. The radiation response of adherens and tight junction proteins was so far mostly investigated with large single-dose irradiation protocols, in vivo and in vitro. Therefore, the current study was initiated to investigate the impact of daily fractionated irradiation on the expression of adherens and tight junction proteins in vivo.

Materials and methods

Fractionation with 5 × 3 Gy/week (days 0–4, 7–11) was given to the snouts of mice. Groups of 5 animals per day were euthanized every second day between day 0 (unirradiated controls) and day 14, and their tongues subjected to histological processing. Adherens junction marker (β-catenin and E‑cadherin) and tight junction marker (claudin-1 and occludin) expression was analysed in the oral mucosa of unirradiated controls and during two weeks of fractionated irradiation.

Results

Adherens as well as tight junction marker proteins were rapidly and consistently upregulated in both the germinal as well as the functional layer of the oral mucosa. This represents a previously unknown parameter of the epithelial radiation response to clinically relevant fractionation protocols.

Conclusion

Fractionated irradiation significantly enhanced the expression of all proteins investigated. This study revealed a new parameter of the epithelial radiation response to fractionated irradiation.

Electronic supplementary material

The online version of this article (10.1007/s00066-018-1302-6) contains supplementary material, which is available to authorized users.