Radiation-induced enteropathy: Molecular basis of pentoxifylline–vitamin E anti-fibrotic effect involved TGF-β1 cascade inhibition

Prophylactic Use of Pentoxifylline and Tocopherol for Prevention of Osteoradionecrosis of the Jaw after Dental Extraction in Post-Radiated Oral and Oropharyngeal Cancer Patients: An Initial Case Series

Osteoradionecrosis of the jaw is a morbid complication of radiotherapy in patients with oral and oropharyngeal cancers that may be precipitated by dental extractions. Pentoxifylline and tocopherol (PENTO) has been utilized in the management of osteoradionecrosis and as prophylaxis for post-radiated head and neck oncology patients requiring an invasive dental procedure. This observational study aims to report the outcome of the prophylactic use of PENTO in the prevention of osteoradionecrosis of the jaw after dental extractions in post-radiated oral and oropharyngeal cancer patients and to review the current literature on this topic. Four post-radiated oral and oropharyngeal oncology patients were referred to the dental oncology clinic of the University Dental Practice, University of Tennessee Health Sciences Center for dental extractions. All four patients were prescribed pentoxifylline 400 mg BID (twice a day) and tocopherol 400 IU BID (oral tablets) for 2 weeks before extraction(s) and for 6 weeks after extraction(s). All patients were followed up every week after the second week post-extraction if feasible until the extraction site(s) healed (covered by mucosa). The assessment endpoint was defined as 6 weeks post-extraction with the outcomes assessed as using four categories determined by the area of exposed bone: complete healing (complete mucosal coverage of extraction site); partial healing (reduction in size of extraction site); no change; and progression (increase in size of the extraction site). At the assessment endpoint, all patients had complete healing of all extraction sites. The ORN rate at the patient level (0/4) and individual tooth level (0/8) was 0%. All patients tolerated the PENTO medications and no adverse effects from the use of these medications were reported. This limited study in addition to the other reviewed studies estimates the rate of ORN at the patient level as 3.2% (14/436) for post-radiated head and neck oncology patients after dental extractions/invasive oral procedures. In conclusion, this PENTO regimen can reduce/prevent the incidence of ORN in post-radiated head and neck oncology patients. This safe and cost-effective protocol (PENTO regimen) should be further evaluated as prophylaxis for post-radiated head and neck oncology patients requiring an invasive dental procedure. We recommend large prospective studies to be carried out to further validate these findings.

Brachial plexopathy after breast cancer: A persistent late effect of radiotherapy

Radiation-induced brachial plexopathy (RIBP) is an iatrogenic, progressively disabling, and often very late effect of adjuvant radiotherapy most commonly seen in breast cancer survivors but also in those treated for lymphoma, lung, and head and neck cancers. In late-onset RIBP following breast cancer, the nerve injury is chronic and irreversible, occurring more commonly when axillary and/or supraclavicular nodes have been irradiated, as well as the breast/chest wall. RIBP is manifested initially by paresthesia, hypoesthesia, dysesthesia, and later by weakness in the ipsilateral hand with those symptoms progressing distally to proximally up through the shoulder. Depressed/absent deep tendon reflexes in the upper extremity and muscle fasciculations occur also. Neither patients nor their health care providers tend to associate these unusual neurological symptoms with cancer treatments received ≥20 years prior, often failing to link these sensory-motor symptoms with radiotherapy decades before. Because long-term follow-up of these patients now typically falls to general practitioners, many cases may be missed or misdiagnosed because of the rarity of this disorder. Physiatrists and allied rehabilitation professionals must be aware of this progressively disabling, incurable condition to provide appropriate diagnoses and compensatory rehabilitation therapies. Additionally, professional oncology organizations should include RIBP in their long-term, survivorship guidelines for breast cancer. Researchers examining the iatrogenic late effects of radiotherapy should extend their follow-up periods well beyond the current 5-6 years to ascertain the true incidence of RIBP today. Rehabilitation providers must continue to advocate for awareness, diagnosis, and management of iatrogenic outcomes experienced by long-term cancer survivors.

The effect of Trolox on the rabbit anal sphincterotomy repair

INTRODUCTION

Fecal incontinence (FI) is caused by external anal sphincter injury. Vitamin E is a potential strategy for anal sphincter muscle repair via its antioxidant, anti-inflammatory, anti-fibrotic, and protective properties against myocyte loss. Thus, we aimed to evaluate the water-soluble form of vitamin E efficacy in repairing anal sphincter muscle defects in rabbits.

METHODS

Twenty-one male rabbits were equally assigned to the intact (without any intervention), control (sphincterotomy), and Trolox (sphincterotomy + Trolox administration) groups. Ninety days after sphincterotomy, the resting and squeeze pressures were evaluated by manometry, and the number of motor units in the sphincterotomy site was calculated by electromyography. Also, the amount of muscle and collagen in the injury site was investigated by Mallory's trichrome staining.

RESULTS

Ninety days after the intervention, the resting and squeeze pressures in the intact and Trolox groups were significantly higher than in the control group (P = 0.001). Moreover, the total collagen percentage of the sphincterotomy site was significantly lower in the Trolox group than in the control group (P = 0.002), and the total muscle percentage was significantly higher in the Trolox group compared to the control group (P = 0.001). Also, the motor unit number was higher in the Trolox group than in the control group (P = 0.001).

CONCLUSION

Trolox administration in the rabbit sphincterotomy model can decrease the amount of collagen and increase muscle, leading to improved anal sphincter electromyography and manometry results. Therefore, Trolox is a potential treatment strategy for FI.

Therapeutic Potential of the Combination of Pentoxifylline and Vitamin-E in Inflammatory Bowel Disease: Inhibition of Intestinal Fibrosis

Background: Although intestinal fibrosis is a consequence of recurrent inflammation in Inflammatory bowel disease (IBD), alleviating inflammation alone does not prevent the progression of fibrosis, suggesting that the development of direct anti-fibrotic agents is necessary. This study aimed to evaluate the anti-fibrotic properties of combination treatment with pentoxifylline (PTX) and vitamin E (Vit-E) on human primary intestinal myofibroblasts (HIMFs) and the therapeutic potential of the combination therapy in murine models of IBD. Methods: HIMFs were pretreated with PTX, Vit-E, or both, and incubated with TGF-β1. We performed Western blot, qPCR, collagen staining, and immunofluorescence to estimate the anti-fibrotic effects of PTX and Vit-E. The cytotoxicity of these was investigated through MTT assay. To induce murine models of IBD for in vivo study, C57BL/6 mice were treated with repeated cycles of dextran sulfate sodium (DSS), developing chronic colitis. We examined whether the combined PTX and Vit-E treatment would effectively ameliorate colonic fibrosis in vivo. Results: We found that the co-treatment with PTX and Vit-E suppressed TGF-β1-induced expression of fibrogenic markers, with decreased expression of pERK, pSmad2, and pJNK, more than either treatment alone in HIMFs. Neither PTX nor Vit-E showed any significant cytotoxicity in given concentrations. Consistently with the in vitro results, the co-administration with PTX and Vit-E effectively attenuated colonic fibrosis with recovery from thickening and shortening of colon in murine models of IBD. Conclusions: These findings demonstrated that the combination of PTX and Vit-E exhibits significant anti-fibrotic effects in both HIMFs and in vivo IBD models, providing a promising therapy for IBD.

Radiation-Induced Fibrosis in Patients with Head and Neck Cancer: A Review of Pathogenesis and Clinical Outcomes

Radiotherapy-related fibrosis remains one of the most challenging treatment related side effects encountered by patients with head and neck cancer. Several established and ongoing novel therapies have been studied with paucity of data in how to best treat these patients. This review aims to provide researchers and health care providers with a comprehensive review on the presentation, etiology, and therapeutic options for this serious condition.

Peripheral Nervous System Involvement in Non-Primary Pediatric Cancer: From Neurotoxicity to Possible Etiologies

Peripheral neuropathy is a well described complication in children with cancer. Oncologists are generally well aware of the toxicity of the main agents, but fear the side effects of new drugs. As chemotherapeutic agents have been correlated with the activation of the immune system such as in Chemotherapy Induced Peripheral Neuropathy (CIPN), an abnormal response can lead to Autoimmune Peripheral Neuropathy (APN). Although less frequent but more severe, Radiation Induced Peripheral Neuropathy may be related to irreversible peripheral nervous system (PNS). Pediatric cancer patients also have a higher risk of entering a Pediatric Intensive Care Unit for complications related to therapy and disease. Injury to peripheral nerves is cumulative, and frequently, the additional stress of a malignancy and its therapy can unmask a subclinical neuropathy. Emerging risk factors for CIPN include treatment factors such as dose, duration and concurrent medication along with patient factors, namely age and inherited susceptibilities. The recent identification of individual genetic variations has advanced the understanding of physiopathological mechanisms and may direct future treatment approaches. More research is needed on pharmacological agents for the prevention or treatment of the condition as well as rehabilitation interventions, in order to allow for the simultaneous delivery of optimal cancer therapy and the mitigation of toxicity associated with pain and functional impairment. The aim of this paper is to review literature data regarding PNS complications in non-primary pediatric cancer.

Gastrointestinal Toxicity of Pelvic Radiotherapy: Are We Letting Women Down?

For all cancers there are four areas of importance: prevention, early diagnosis, optimising therapy and living with and beyond. For women diagnosed with gynaecological cancers, progress in these first three areas has been immense. However, living with and beyond has largely been ignored as a significant issue. As a group, patients treated for gynaecological cancer are more often young and more often suffer the most difficult long-term issues. Despite the growing number of long-term survivors, little has been done to ensure appropriate assessment and treatment of side-effects of cancer therapies, especially when radiotherapy has been used. For many affected patients their symptoms become part of everyday life, 'normality' is adjusted and these changes are tolerated even when severely limiting activities. Data show that even expert clinicians frequently do not appreciate the true impact of these problems and the focus of treatment and of follow-up remains fixed on 5-year survival and cancer recurrence, respectively. Many clinicians are unaware of what experts can do for toxicity and do not know where to refer their patients. However, rapid identification of patients with significant symptoms can lead to earlier diagnosis of treatable pathologies and improvement in patients' quality of life. In addition, the underlying pathophysiology of radiation-induced damage is potentially amenable to disease-modifying therapies. This review focuses on the factors that contribute to patients developing pelvic radiation disease, what can be done to mitigate the toxicity of treatment and highlights the challenges that must be addressed to reduce the gastrointestinal toxicity of pelvic radiotherapy.

Radiotherapy-Specific Chronic Pain Syndromes in the Cancer Population: An Evidence-Based Narrative Review

While radiation therapy is increasingly utilized in the treatment paradigm of many solid cancers, the chronic effects of radiation therapies are poorly characterized. Notably, understanding radiation-specific chronic pain syndromes is paramount given that the diagnosis and management of these conditions can serve to prevent long-standing functional impairments, optimize quality of life, and even allow for continued radiotherapy candidacy. These radiation-specific chronic pain phenomena include dermatitis, mucositis, enteritis, connective tissue fibrosis, lymphedema, and neuropathic pain syndromes. It is necessary to maintain a low threshold of suspicion for appropriately diagnosing these conditions as there exists a variance in when these symptoms arise after radiation. However, we present key epidemiological data delineating vulnerable cancer populations for each pain syndrome along with the available evidence for the management for each specific condition.

Intestinal stenosis in Crohn's disease shows a generalized upregulation of genes involved in collagen metabolism and recognition that could serve as novel anti-fibrotic drug targets

BACKGROUND AND AIMS

Crohn's disease (CD) can be complicated by intestinal fibrosis. Pharmacological therapies against intestinal fibrosis are not available. The aim of this study was to determine whether pathways involved in collagen metabolism are upregulated in intestinal fibrosis, and to discuss which drugs might be suitable to inhibit excessive extracellular matrix formation targeting these pathways.

METHODS

Human fibrotic and non-fibrotic terminal ileum was obtained from patients with CD undergoing ileocecal resection due to stenosis. Genes involved in collagen metabolism were analyzed using a microfluidic low-density TaqMan array. A literature search was performed to find potential anti-fibrotic drugs that target proteins/enzymes involved in collagen synthesis, its degradation and its recognition.

RESULTS

mRNA expression of collagen type I (COL1A1, 0.76 ± 0.28 versus 37.82 ± 49.85, p = 0.02) and III (COL3A1, 2.01 ± 2.61 versus 68.65 ± 84.07, p = 0.02) was increased in fibrotic CD compared with non-fibrotic CD. mRNA expression of proteins involved in both intra- and extracellular post-translational modification of collagens (prolyl- and lysyl hydroxylases, lysyl oxidases, chaperones), collagen-degrading enzymes (MMPs and cathepsin-K), and collagen receptors were upregulated in the fibrosis-affected part. A literature search on the upregulated genes revealed several potential anti-fibrotic drugs.

CONCLUSION

Expression of genes involved in collagen metabolism in intestinal fibrosis affected terminal ileum of patients with CD reveals a plethora of drug targets. Inhibition of post-translational modification and altering collagen metabolism might attenuate fibrosis formation in the intestine in CD. Which compound has the highest potential depends on a combination anti-fibrotic efficacy and safety, especially since some of the enzymes play key roles in the physiology of collagen.

Breast Implants and Radiation

One of the most influential factors in the success of breast reconstruction is whether or not radiation therapy has or will be performed. While traditional teaching is that all breasts treated with radiation therapy must be reconstructed with an autologous component, many reconstructive surgeons perform implant-based breast reconstruction without an autologous component and have success doing so. The purpose of this article is to explore the risks, benefits, and nuances of performing implant-based breast reconstruction in the setting of radiation therapy. The authors performed a review of the literature of all topics relevant to performing implant-based reconstruction with radiation therapy.

Association Between Inflammatory Biomarker C-Reactive Protein and Radiotherapy-Induced Early Adverse Skin Reactions in a Multiracial/Ethnic Breast Cancer Population

Purpose This study examined an inflammatory biomarker, high-sensitivity C-reactive protein (hsCRP), in radiotherapy (RT)-induced early adverse skin reactions or toxicities in breast cancer. Patients and Methods Between 2011 and 2013, 1,000 patients with breast cancer who underwent RT were evaluated prospectively for skin toxicities through the National Cancer Institute-funded Wake Forest University Community Clinical Oncology Program Research Base. Pre- and post-RT plasma hsCRP levels and Oncology Nursing Society skin toxicity criteria (0 to 6) were used to assess RT-induced skin toxicities. Multivariable logistic regression analyses were applied to ascertain the associations between hsCRP and RT-induced skin toxicities after adjusting for potential confounders. Results The study comprised 623 white, 280 African American, 64 Asian/Pacific Islander, and 33 other race patients; 24% of the patients were Hispanic, and 47% were obese. Approximately 42% and 15% of patients developed RT-induced grade 3+ and 4+ skin toxicities, respectively. The hsCRP levels differed significantly by race and body mass index but not by ethnicity. In multivariable analysis, grade 4+ skin toxicity was significantly associated with obesity (odds ratio [OR], 2.17; 95% CI, 1.41 to 3.34], post-RT hsCRP ≥ 4.11 mg/L (OR, 1.61; 95% CI, 1.07 to 2.44), and both factors combined (OR, 3.65; 95% CI, 2.18 to 6.14). Above-median post-RT hsCRP (OR, 1.93; 95% CI, 1.03 to 3.63), and change in hsCRP (OR, 2.80; 95% CI, 1.42 to 5.54) were significantly associated with grade 4+ skin toxicity in nonobese patients. Conclusion This large prospective study is the first to our knowledge of hsCRP as an inflammatory biomarker in RT-induced skin toxicities in breast cancer. We demonstrate that nonobese patients with elevated RT-related change in hsCRP levels have a significantly increased risk of grade 4+ skin toxicity. The outcomes may help to predict RT responses and guide decision making.

Pentoxifylline and vitamin E drug compliance after adjuvant breast radiation therapy

PURPOSE

Breast fibrosis is a common late effect after therapeutic irradiation that can result in pain, poor cosmesis, and functional impairment. Randomized trials have demonstrated that radiation fibrosis may be preventable with a medication regimen of pentoxifylline and vitamin E. This study investigates patient compliance with pentoxifylline therapy while examining possible correlations to compliance.

METHODS AND MATERIALS

We identified 90 patients who were prescribed pentoxifylline (400 mg 3 times daily) and vitamin E (400 IU once daily) after adjuvant breast radiation. A retrospective cohort study was conducted using medical record analysis. Data were collected, including patient age, comorbid conditions, concurrent medications, duration of pentoxifylline and vitamin E therapy, dose adjustments, patient-reported side effects, and cause for discontinuation. A multivariate analysis of the correlation between medication compliance and these categorical variables was assessed with a χ2 analysis of independence.

RESULTS

Patient compliance with pentoxifylline and vitamin E therapy was found to be poor in 33 of 87 patients (38%) in the cohort, necessitating either dose reductions or discontinuation of therapy. There was a statistically significant correlation between concurrent antiemetic therapy and successful completion of pentoxifylline regimen. Of those on antiemetic therapy, 89% completed pentoxifylline as prescribed versus 48% of those without antiemetics (P < .001). There was a statistically significant correlation between concurrent proton pump inhibitor (PPI) therapy and discontinuation of pentoxifylline. Of those on PPI therapy, 33% completed pentoxifylline versus 81% of those not on PPIs (P < .001). All other variables examined were not significantly correlated with compliance.

CONCLUSIONS

Patient compliance with pentoxifylline appears to be worse in clinical practice compared with previously published studies. Nausea was the most frequently reported indication for treatment modification or discontinuation. Concurrent antiemetic therapy was correlated with strong regimen compliance, but concurrent PPI therapy was correlated with poor compliance, independent of comorbid conditions.

Antioxidant Supplementation: A Linchpin in Radiation-Induced Enteritis

Radiation enteritis is one of the most feared complications of abdominal and pelvic regions. Thus, radiation to abdominal or pelvic malignancies unavoidably injures the intestine. Because of rapid cell turnover, the intestine is highly sensitive to radiation injury, which is the limiting factor in the permissible dosage of irradiation. Bowel injuries such as fistulas, strictures, and chronic malabsorption are potentially life-threatening complications and have an impact on patient quality of life. The incidence of radiation enteritis is increasing because of the current trend of combined chemotherapy and radiation. The consequences of radiation damage to the intestine may result in considerable morbidity and even mortality. The observed effects of ionizing radiation are mediated mainly by oxygen-free radicals that are generated by its action on water and are involved in several steps of signal transduction cascade, leading to apoptosis. The oxyradicals also induce DNA strand breaks and protein oxidation. An important line of defense against free radical damage is the presence of antioxidants. Therefore, administration of antioxidants may ameliorate the radiation-induced damage to the intestine.

Current Status of Targeted Radioprotection and Radiation Injury Mitigation and Treatment Agents: A Critical Review of the Literature

As more cancer patients survive their disease, concerns about radiation therapy-induced side effects have increased. The concept of radioprotection and radiation injury mitigation and treatment offers the possibility to enhance the therapeutic ratio of radiation therapy by limiting radiation therapy-induced normal tissue injury without compromising its antitumor effect. Advances in the understanding of the underlying mechanisms of radiation toxicity have stimulated radiation oncologists to target these pathways across different organ systems. These generalized radiation injury mechanisms include production of free radicals such as superoxides, activation of inflammatory pathways, and vascular endothelial dysfunction leading to tissue hypoxia. There is a significant body of literature evaluating the effectiveness of various treatments in preventing, mitigating, or treating radiation-induced normal tissue injury. Whereas some reviews have focused on a specific disease site or agent, this critical review focuses on a mechanistic classification of activity and assesses multiple agents across different disease sites. The classification of agents used herein further offers a useful framework to organize the multitude of treatments that have been studied. Many commonly available treatments have demonstrated benefit in prevention, mitigation, and/or treatment of radiation toxicity and warrant further investigation. These drug-based approaches to radioprotection and radiation injury mitigation and treatment represent an important method of making radiation therapy safer.

The Role of Lymphocytes in Radiotherapy-Induced Adverse Late Effects in the Lung

Radiation-induced pneumonitis and fibrosis are dose-limiting side effects of thoracic irradiation. Thoracic irradiation triggers acute and chronic environmental lung changes that are shaped by the damage response of resident cells, by the resulting reaction of the immune system, and by repair processes. Although considerable progress has been made during the last decade in defining involved effector cells and soluble mediators, the network of pathophysiological events and the cellular cross talk linking acute tissue damage to chronic inflammation and fibrosis still require further definition. Infiltration of cells from the innate and adaptive immune systems is a common response of normal tissues to ionizing radiation. Herein, lymphocytes represent a versatile and wide-ranged group of cells of the immune system that can react under specific conditions in various ways and participate in modulating the lung environment by adopting pro-inflammatory, anti-inflammatory, or even pro- or anti-fibrotic phenotypes. The present review provides an overview on published data about the role of lymphocytes in radiation-induced lung disease and related damage-associated pulmonary diseases with a focus on T lymphocytes and B lymphocytes. We also discuss the suspected dual role of specific lymphocyte subsets during the pneumonitic phase and fibrotic phase that is shaped by the environmental conditions as well as the interaction and the intercellular cross talk between cells from the innate and adaptive immune systems and (damaged) resident epithelial cells and stromal cells (e.g., endothelial cells, mesenchymal stem cells, and fibroblasts). Finally, we highlight potential therapeutic targets suited to counteract pathological lymphocyte responses to prevent or treat radiation-induced lung disease.

Prophylactic use of pentoxifylline (Trental) and vitamin E to prevent capsular contracture after implant reconstruction in patients requiring adjuvant radiation

BACKGROUND

The combination of pentoxifylline (Trental) and vitamin E has been reported to reverse significant consequences of radiation after mastectomy with immediate reconstruction, such as severe capsular contracture or loss of implants. We questioned whether prophylactic use could prevent these consequences.

METHODS

Thirty women with implants or tissue expanders after mastectomy that underwent adjuvant radiation were treated with Trental and vitamin E for 180 days. All subjects then entered a 12-month observational phase.

RESULTS

Of the 26 evaluable subjects, 3 subjects required implant revisions. One due to malposition of the nonradiated breast and 2 were due to contracture (7.7%). There were no implant losses.

CONCLUSIONS

The combination of Trental and vitamin E can prevent severe contracture and implant losses allowing for immediate reconstruction with implant or tissue expander even if radiation is planned after mastectomy.

SKI2162, an inhibitor of the TGF-β type I receptor (ALK5), inhibits radiation-induced fibrosis in mice

Here we demonstrated that SKI2162, a small-molecule inhibitor of the TGF-β type I receptor (ALK5), prevented radiation-induced fibrosis (RIF) in mice. SKI2162 inhibited phosphorylation of Smad and induction of RIF-related genes in vitro. In RIF a mouse model, SKI2162 reduced late skin reactions and leg-contracture without jeopardizing the acute skin reaction. Irradiation of mouse tissue increased COL1A2 mRNA levels, and topical administration of SKI2162 significantly inhibited this effect. Thus, these findings support that SKI2162 has potential value as novel RIF-protective agent, and could be candidate for clinical trials.

Bone marrow derived macrophages fuse with intestine stromal cells and contribute to chronic fibrosis after radiation

BACKGROUND AND PURPOSE

Bone marrow-derived cells (BMDC) have been demonstrated to play a critical role in intestine regeneration. However, organ fibrosis was one of the major side effects of bone marrow (BM) transplantation. It warrants further investigation on the mechanisms of BM cell therapy in radiation induced intestine damage.

MATERIALS AND METHODS

We established three murine models to evaluate BMDC within intestines after radiation, including cre-loxP system of transgenic mice. In vitro co-culture between murine BM with human intestine stromal cells was also performed to measure the level of fusion and fibrosis after treatment with anti-fibrotic agents or after macrophage depletion.

RESULTS

Despite complete recovery of epithelial mucosa from radiation damage, we found persistent proliferation and repopulation of BMDC within the lamina propria. Fusion between BM derived monocytic and intestine stromal cells correlated with the level of fibrosis and proliferation index. Depleting macrophages genetically using CD11b-DTR mouse model or pharmacologically using clodronate liposome reduced the level of cell fusion and intestine fibrosis.

CONCLUSIONS

Fibrotic cues from intestine enhance fusion between BM-derived monocytes/macrophages with intestine stromal cells. The fusion hybrids promote cell cycle re-entry, proliferation and reinforce fibrosis signal. Depleting macrophages interferes with cell fusion and ameliorates radiation-induced intestine fibrosis.

Pain in cancer survivors

Cancer and its treatment exert a heavy psychological and physical toll. Of the myriad symptoms which result, pain is common, encountered in between 30% and 60% of cancer survivors. Pain in cancer survivors is a major and growing problem, impeding the recovery and rehabilitation of patients who have beaten cancer and negatively impacting on cancer patients' quality of life, work prospects and mental health. Persistent pain in cancer survivors remains challenging to treat successfully. Pain can arise both due to the underlying disease and the various treatments the patient has been subjected to. Chemotherapy causes painful chemotherapy-induced peripheral neuropathy (CIPN), radiotherapy can produce late effect radiation toxicity and surgery may lead to the development of persistent post-surgical pain syndromes. This review explores a selection of the common causes of persistent pain in cancer survivors, detailing our current understanding of the pathophysiology and outlining both the clinical manifestations of individual pain states and the treatment options available.

Caffeic acid phenethyl ester attenuates ionize radiation-induced intestinal injury through modulation of oxidative stress, apoptosis and p38MAPK in rats

Caffeic acid phenyl ester (CAPE) is a potent anti-inflammatory agent and it can eliminate the free radicals. This study aimed to investigate the radioprotective effects of CAPE on X-ray irradiation induced intestinal injury in rats. Rats were intragastrically administered with 10 μmol/kg/d CAPE for 7 consecutive days before exposing them to a single dose of X-ray irradiation (9Gy) to abdomen. Rats were sacrificed 72 h after exposure to radiation. We found that pretreatment with CAPE effectively attenuated intestinal pathology changes, apoptosis, oxidative stress, bacterial translocation, the content of nitric oxide and myeloperoxidase as well as the concentration of plasma tumor necrosis factor-α. Pretreatment with CAPE also reversed the activation of p38MAPK and the increased expression of intercellular cell adhesion molecule-1 induced by radiation in intestinal mucosa. Taken together, these results suggest that pretreatment with CAPE could be a promising candidate for treating radiation-induced intestinal injury.

Lumbosacral plexopathy: A rare long term complication of concomitant chemo-radiation for cervical cancer

Radiation induced Lumbosacral plexophaty (RILP) is a rare but severe complication that has a considerable impact on quality of life. Its occurrence is rare but increasing with improved long-term cancer survival. This entity commonly results in different degrees of sensory and motor deficits. The pathophysiological mechanisms are not yet fully understood. Diagnosis of radiation myelopathy in women with gynecologic malignancies may increase with the use of concomitant chemo-radiation. This report describes the effect of this combination therapy in a 64-year-old woman with cervical carcinoma.

2013 Dade W. Moeller lecture: medical countermeasures against radiological terrorism

Soon after the 9-11 attacks, politicians and scientists began to question our ability to cope with a large-scale radiological terrorism incident. The outline of what was needed was fairly obvious: the ability to prevent such an attack, methods to cope with the medical consequences, the ability to clean up afterward, and the tools to figure out who perpetrated the attack and bring them to justice. The medical response needed three components: the technology to determine rapidly the radiation doses received by a large number of people, methods for alleviating acute hematological radiation injuries, and therapies for mitigation and treatment of chronic radiation injuries. Research done to date has shown that a realistic medical response plan is scientifically possible, but the regulatory and financial barriers to achieving this may currently be insurmountable.

Hepatoprotective effects of loach (Misgurnus anguillicaudatus) lyophilized powder on dimethylnitrosamine-induced liver fibrosis in rats

This study investigates the hepatoprotective effects and the potential therapeutic mechanisms of loach (Misgurnus anguillicaudatus) lyophilized powder (MLP) on dimethylnitrosamine (DMN) induced liver fibrosis in rats. After treatment with MLP (50, 100, 200 mg/kg), alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin (Alb), total protein (TP) and hydroxyproline (Hyp) levels were detected, to assess the destruction of hepatocytes and the extent of liver fibrosis. Matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), hyaluronic acid (HA), Laminin (LN), procollagen type-III (PC-III), collagen type-IV (C-IV), and transforming growth factor-β₁ (TGF-β₁) contents in serum were all tested using ELISA kits. Alpha-smooth muscle actin (α-SMA) and the tissue inhibitor of metalloproteinase-1 (TIMP-1) protein contents and distribution were evaluated using western blot and immunohistochemical analysis. MLP significantly decreased the serum concentrations of ALT, AST, Hyp, HA, LN, PC-III, C-IV, MMP-2, TIMP-1, α-SMA and TGF-β₁, while increasing the contents of Alb and MMP-9. No significant changes on TP serum concentrations were observed. These results suggest that MLP has anti-hepatic fibrosis effects and its mechanism may be associated with the attenuation of extracellular matrix (ECM) synthesis, the acceleration of ECM degradation, inhibition of hepatic stellate cells (HSCs) activation and TGF-β₁ expression.

Inflammatory biomarker C-reactive protein and radiotherapy-induced early adverse skin reactions in patients with breast cancer

BACKGROUND

Breast cancer is the most frequently diagnosed cancer and the second leading cause of cancer death in American women. Postsurgery adjuvant radiotherapy (RT) significantly reduced the local recurrence rate. However, many patients develop early adverse skin reactions (EASR) that impact quality of life and treatment outcomes.

METHODS

We evaluated an inflammatory biomarker, C-reactive protein (CRP), in predicting RT-induced EASRs in 159 patients with breast cancer undergoing RT. In each patient, we measured pre- and post-RT plasma CRP levels using a highly sensitive ELISA CRP assay. RT-induced EASRs were assessed at weeks 3 and 6 using the National Cancer Institute Common Toxicity Criteria (v3.0). Associations between EASRs and CRP levels were assessed using logistic regression models after adjusting for potential confounders.

RESULTS

RT-induced grade 2+ EASRs were observed in 8 (5%) and 80 (50%) patients at weeks 3 and 6 (end of RT), respectively. At the end of RT, a significantly higher proportion of African Americans developed grade 3 EASRs (13.8% vs. 2.3% in others); grade 2+ EASRs were significantly associated with: change of CRP > 1 mg/L [odds ratio (OR), 2.51; 95% confidence interval (CI), 1.06-5.95; P = 0.04], obesity (OR, 2.08; 95% CI, 1.03-4.21; P = 0.04), or combined both factors (OR, 5.21; 95% CI, 1.77-15.38; P = 0.003).

CONCLUSION

This is the first study to demonstrate that an inflammatory biomarker CRP is associated with RT-induced EASRs, particularly combined with obesity.

IMPACT

Future larger studies are warranted to validate our findings and facilitate the discovery and development of anti-inflammatory agents to protect normal tissue from RT-induced adverse effects and improve quality of life in patients with breast cancer undergoing RT.

Epigenetics in radiation-induced fibrosis

Radiotherapy is a major cancer treatment option but dose-limiting side effects such as late-onset fibrosis in the irradiated tissue severely impair quality of life in cancer survivors. Efforts to explain radiation-induced fibrosis, for example, by genetic variation remained largely inconclusive. Recently published molecular analyses on radiation response and fibrogenesis showed a prominent role of epigenetic gene regulation. This review summarizes the current knowledge on epigenetic modifications in fibrotic disease and radiation response, and it points out the important role for epigenetic mechanisms such as DNA methylation, microRNAs and histone modifications in the development of this disease. The synopsis illustrates the complexity of radiation-induced fibrosis and reveals the need for investigations to further unravel its molecular mechanisms. Importantly, epigenetic changes are long-term determinants of gene expression and can therefore support those mechanisms that induce and perpetuate fibrogenesis even in the absence of the initial damaging stimulus. Future work must comprise the interconnection of acute radiation response and long-lasting epigenetic effects in order to assess their role in late-onset radiation fibrosis. An improved understanding of the underlying biology is fundamental to better comprehend the origin of this disease and to improve both preventive and therapeutic strategies.

The relation of radiation-induced pulmonary fibrosis with stress and the efficiency of antioxidant treatment: an experimental study

BACKGROUND

Radiation-Induced Lung Injury has 2 components: radiation pneumonitis and radiation fibrosis. The pulmonary fibrosis has no known efficient treatment. The purpose of this study was to study the relationship between the oxidant/antioxidant status and pulmonary fibrosis in rats having radiation induced pulmonary fibrosis and to study the antioxidant effects of pentoxifylline, vitamin E, and vitamin C in the treatment of pulmonary fibrosis.

MATERIAL AND METHODS

The study rats were divided into 5 groups: Thoracic RT + vitamin E+ Pentoxifylline for group 1, Thoracic RT + vitamin C + Pentoxifylline for group 2, Thoracic RT + vitamin C + vitamin E + Pentoxifylline for group 3, and Thoracic RT + Pentoxifylline for group 4, and group 5 was the control group.

RESULTS

When groups are evaluated in pairs, significant differences between group 1 and 2, group 1 and 4, and group 1 and 5 were determined (p: 0.002, p: 0.002, p<0.001, respectively). No significant difference was determined between group 1 and 3 (p: 0.161). No significant difference was determined between group 2 and group 3, 4, and 5 (p: 0.105, p: 0.645, p: 0.234, respectively). There was no significant difference between group 4 and 5 (p: 0.645).

CONCLUSIONS

The combination of vitamin E and pentoxifylline is efficient in preventing radiation-induced lung fibrosis. The additional benefit of vitamin C, which is added to this combination to increase the antioxidant activity, cannot be shown. It would be useful to investigate the combination of vitamin E, pentoxifylline, and other non-enzymatic antioxidants.

Radiation enteritis

Radiation enteritis continues to be a major health concern in recipients of radiation therapy. The incidence of radiation enteritis is expected to continue to rise during the coming years paralleling the unprecedented use of radiotherapy in pelvic cancers. Radiation enteritis can present as either an acute or chronic syndrome. The acute form presents within hours to days of radiation exposure and typically resolves within few weeks. The chronic form may present as early as 2 months or as long as 30 years after exposure. Risk factors can be divided into patient and treatment-related factors. Chronic radiation enteritis is characterized by progressive obliterative endarteritis with exaggerated submucosal fibrosis and can manifest by stricturing, formation of fistulae, local abscesses, perforation, and bleeding. In the right clinical context, diagnosis can be confirmed by cross-sectional imaging, flexible or video capsule endoscopy. Present treatment strategies are directed primarily towards symptom relief and management of emerging complications. Recently, however, there has been a shift towards rational drug design based on improved understanding of the molecular basis of disease in an effort to limit the fibrotic process and prevent organ damage.

MiR-210: A potential therapeutic target against radiation-induced enteropathy

A previously undescribed and robust miR210 overexpression is shown in intestinal samples obtained from patients with radiation enteropathy and fibrotic cultured cells. In addition, miR-210 overexpression is repressed by antifibrotic treatment combining pentoxifylline and α-tocopherol.

Pharmacological induction of transforming growth factor-beta1 in rat models enhances radiation injury in the intestine and the heart

Radiation therapy in the treatment of cancer is dose limited by radiation injury in normal tissues such as the intestine and the heart. To identify the mechanistic involvement of transforming growth factor-beta 1 (TGF-β1) in intestinal and cardiac radiation injury, we studied the influence of pharmacological induction of TGF-β1 with xaliproden (SR 57746A) in rat models of radiation enteropathy and radiation-induced heart disease (RIHD). Because it was uncertain to what extent TGF-β induction may enhance radiation injury in heart and intestine, animals were exposed to irradiation schedules that cause mild to moderate (acute) radiation injury. In the radiation enteropathy model, male Sprague-Dawley rats received local irradiation of a 4-cm loop of rat ileum with 7 once-daily fractions of 5.6 Gy, and intestinal injury was assessed at 2 weeks and 12 weeks after irradiation. In the RIHD model, male Sprague-Dawley rats received local heart irradiation with a single dose of 18 Gy and were followed for 6 months after irradiation. Rats were treated orally with xaliproden starting 3 days before irradiation until the end of the experiments. Treatment with xaliproden increased circulating TGF-β1 levels by 300% and significantly induced expression of TGF-β1 and TGF-β1 target genes in the irradiated intestine and heart. Various radiation-induced structural changes in the intestine at 2 and 12 weeks were significantly enhanced with TGF-β1 induction. Similarly, in the RIHD model induction of TGF-β1 augmented radiation-induced changes in cardiac function and myocardial fibrosis. These results lend further support for the direct involvement of TGF-β1 in biological mechanisms of radiation-induced adverse remodeling in the intestine and the heart.

Radiation-induced neuropathy in cancer survivors

Radiation-induced peripheral neuropathy is a chronic handicap, frightening because progressive and usually irreversible, usually appearing several years after radiotherapy. Its occurrence is rare but increasing with improved long-term cancer survival. The pathophysiological mechanisms are not yet fully understood. Nerve compression by indirect extensive radiation-induced fibrosis plays a central role, in addition to direct injury to nerves through axonal damage and demyelination and injury to blood vessels by ischaemia following capillary network failure. There is great clinical heterogeneity in neurological presentation since various anatomic sites are irradiated. The well-known frequent form is radiation-induced brachial plexopathy (RIBP) following breast cancer irradiation, while tumour recurrence is easier to discount today with the help of magnetic resonance imaging and positron emission tomography. RIBP incidence is in accordance with the irradiation technique, and ranges from 66% RIBP with 60Gy in 5Gy fractions in the 1960s to less than 1% with 50Gy in 2Gy fractions today. Whereas a link with previous radiotherapy is forgotten or difficult to establish, this has recently been facilitated by a posteriori conformal radiotherapy with 3D-dosimetric reconstitution: lumbosacral radiculo-plexopathy following testicular seminoma or Hodgkin's disease misdiagnosed as amyotrophic lateral sclerosis. Promising treatments via the antioxidant pathway for radiation-induced fibrosis suggest a way to improve the everyday quality of life of these long-term cancer survivors.