Pathogenetic mechanisms in radiation fibrosis

[Progression of Anti-oxygen Therapy in Radiation-Induced Lung Injury]

Radiation induced lung injury (RILI) is a serious complication in patients received thoracic radiotherapy. The main clinical symptom of RILI includes short of breath, low fever and cough, seriously affect the survival of patients. How to better prevent and treat RILI is an urgent problem. Target theory, cytokine theory, free radical theory, and vascular endothelial cell damage theory are the main mechanisms of RILI. Among them, reactive oxygen species (ROS) produced during radiotherapy can induce tissue damage throughout the course of RILI, and have a direct effect on both radiation pneumonitis and radiation-induced lung fibrosis. Anti-oxygen therapy including thiol compounds, antioxidant enzymes, and plant antioxidants have been applied in the prevention and treatment of RILI. This article reviews the research and application of antioxidant therapy in RILI.
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Adjuvant radiotherapy-induced cardiac changes among patients with early breast cancer: a three-year follow-up study. Acta Oncol 2019;58:1250-1258. [PMID: 31219359 DOI: 10.1080/0284186x.2019.1630751]

Background: In this study, we evaluate the evolution of cardiac changes during a three-year follow-up after adjuvant breast radiotherapy (RT). Methods: Sixty patients with left-sided and 20 patients with right-sided early stage breast cancer without chemotherapy were included in this prospective study. Echocardiography and cardiac biomarkers were evaluated before, immediately after and 3 years after RT. Radiation doses to cardiac structures were calculated. Results: In echocardiography, left ventricle (LV) systolic measurements had impaired at 3 years compared to baseline: the mean global longitudinal strain (GLS) worsened from -18 ± 3 to -17 ± 3 (p = .015), LV ejection fraction from 62 ± 5% to 60 ± 4% (p = .003) and the stroke volume from 73 ± 16 mL to 69 ± 15 mL (p = .015). LV diastolic function was also negatively affected: the isovolumetric relaxation time was prolonged (p = .006) and the first peak of diastole decreased (p = .022). Likewise, left atrial (LA) measurements impaired. These changes in echocardiography were more prominent in left-sided than in right-sided patients. The concurrent aromatase inhibitor (AI) use was associated with GLS impairment. In all patients, the N-terminal pro-brain natriuretic peptide (proBNP) values were median (interquartile range) 74 (41-125) ng/L at baseline, 75 (41-125) ng/L at the end of RT and 96 (56-162) ng/L at 3 years (p < .001 from baseline to 3 years). However, proBNP did not increase in right-sided patients. Conclusion: During the 3-year follow-up after RT, negative subclinical changes in cardiac biomarkers and in LV systolic and diastolic function were observed. The measured changes were more pronounced in left-sided patients. In addition, AI use was associated with impaired cardiac systolic function.

Discovery of Novel Small Molecules that Block Myofibroblast Formation: Implications for Capsular Contracture Treatment

Capsular contracture is a devastating complication that occurs in patients undergoing implant-based breast reconstruction. Ionizing radiation drives and exacerbates capsular contracture in part by activating cytokines, including transforming growth factor-beta (TGF-β). TGF-β promotes myofibroblast differentiation and proliferation, leading to excessive contractile scar formation. Therefore, targeting the TGF-β pathway may attenuate capsular contracture.

METHODS

A 20,000 small molecule library was screened for anti-TGF-β activity. Structurally diverse anti-TGF-β agents were identified and then tested on primary human capsular fibroblasts. Fibroblasts were irradiated or not, and then treated with both TGF-β and candidate molecules. Resulting cells were then analyzed for myofibroblast activity using myofibroblast markers including alpha-smooth muscle actin, collagen I, Thy1, and periostin, using Western Blot, quantitative real-time polymerase chain reaction, and immunofluorescence.

RESULTS

Human capsular fibroblasts treated with TGF-β showed a significant increase in alpha-smooth muscle actin, collagen I, and periostin levels (protein and/or mRNA). Interestingly, fibroblasts treated with latent TGF-β and 10 Gy radiation also showed significantly increased levels of myofibroblast markers. Cells that were treated with the novel small molecules showed a significant reduction in myofibroblast activation, even in the presence of radiation.

CONCLUSIONS

Several novel small molecules with anti-TGF-β activity can effectively prevent human capsular fibroblast to myofibroblast differentiation in vitro, even in the presence of radiation. These results highlight novel therapeutic options that may be utilized in the future to prevent radiation-induced capsular contracture.

Transforming growth factor beta 1 levels predict echocardiographic changes at three years after adjuvant radiotherapy for breast cancer

BACKGROUND

Transforming growth factor beta 1 (TGF-β1) and platelet-derived growth factor (PDGF) are cytokines involved in fibrotic processes causing radiotherapy (RT)-induced cardiovascular changes. We aimed to investigate the associations between TGF-β1 and PDGF and the echocardiographic changes that occur during RT and during three-year follow-up.

METHODS

The study included 63 women receiving adjuvant RT for early-stage breast cancer or ductal carcinoma in situ. Serum TGF-β1 (ng/ml) and PDGF (ng/ml) levels were measured by enzyme-linked immunoassay and echocardiographic examination was performed before RT, after RT and at 3 years. Patients were grouped by biomarker behavior by a trajectory analysis.

RESULTS

TGF-β1 decreased from 19.2 (IQR 17.1-22.3) before RT to 18.8 (14.5-22.0) after RT (p = 0.003) and the decrease persisted at 17.2 (13.7-21.2) 3 years after RT (p = 0.101). PDGF decreased from 15.4 (12.6-19.1) before RT to 13.8 (11.7-16.2) after RT, p = 0.001, and persisted at 15.6 (10.4-18.4) at 3 years, p = 0.661. The TGF-β1 level before RT (Spearman's rho 0.441, p < 0.001) and the three-year change in TGF-β1 (rho = - 0.302, p = 0.018) correlated with global longitudinal strain (GLS) in echocardiography at 3 years. In trajectory analysis, two TGF-β1 behavior groups were found. Group 1 had significantly higher TGF-β1 levels before RT, 25.6 (22.3-28.6), than group 2, 17.8 (15.9-19.9), p < 0.001. In multivariable analysis, TGF-β1 trajectory group 1 (β = 0.27, p = 0.013), left-sided breast cancer (β = 0.39, p = 0.001) and the use of aromatase inhibitors (β = 0.29, p = 0.011) were significantly associated with a worsening in GLS from before RT to 3 years.

CONCLUSION

An elevated pretreatment TGF-β1 may predict RT-associated changes in echocardiography.

Long-Term Radiotherapy-Induced Cardiac Complications: A Case Report

Patient: Male, 48

Final Diagnosis: Late cardiac complications postradiotherapy

Symptoms: Chest pain • dyspnea • syncope

Medication: —

Clinical Procedure: Diagnostic and therapeutic techniques in cardiology

Specialty: Cardiology

Radiation-induced heart disease: a review of classification, mechanism and prevention

With the increasing incidence of thoracic tumors, radiation therapy (RT) has become an important component of comprehensive treatment. RT improves survival in many cancers, but it involves some inevitable complications. Radiation-induced heart disease (RIHD) is one of the most serious complications. RIHD comprises a spectrum of heart disease including cardiomyopathy, pericarditis, coronary artery disease, valvular heart disease and conduction system abnormalities. There are numerous clinical manifestations of RIHD, such as chest pain, palpitation, and dyspnea, even without obvious symptoms. Based on previous studies, the pathogenesis of RIHD is related to the production and effects of various cytokines caused by endothelial injury, inflammatory response, and oxidative stress (OS). Therefore, it is of great importance for clinicians to identify the mechanism and propose interventions for the prevention of RIHD.

The Role of Mesenchymal Stem Cells in Radiation-Induced Lung Fibrosis

Radiation therapy is one of the most important treatment modalities for thoracic tumors. Despite significant advances in radiation techniques, radiation-induced lung injury (RILI) still occurs in up to 30% of patients undergoing thoracic radiotherapy, and therefore remains the main dose-limiting obstacle. RILI is a potentially lethal clinical complication of radiotherapy that has 2 main stages: an acute stage defined as radiation pneumonitis, and a late stage defined as radiation-induced lung fibrosis. Patients who develop lung fibrosis have a reduced quality of life with progressive and irreversible organ malfunction. Currently, the most effective intervention for the treatment of lung fibrosis is lung transplantation, but the lack of available lungs and transplantation-related complications severely limits the success of this procedure. Over the last few decades, advances have been reported in the use of mesenchymal stem cells (MSCs) for lung tissue repair and regeneration. MSCs not only replace damaged lung epithelial cells but also promote tissue repair through the secretion of anti-inflammatory and anti-fibrotic factors. Here, we present an overview of MSC-based therapy for radiation-induced lung fibrosis, focusing in particular on the molecular mechanisms involved and describing the most recent preclinical and clinical studies carried out in the field.

New therapeutic insights into radiation-induced myocardial fibrosis

Radiation therapy (RT) for the treatment of thoracic tumors causes radiation-induced heart disease (RIHD). Radiation-induced myocardial fibrosis (RIMF) is both an acute and chronic stage of RIHD, depending on the specific pathology, and is thought to be a major risk factor for adverse myocardial remodeling and vascular changes. With the use of more three-dimensional conformal radiation regimens and early screenings and diagnoses for RIMF, the incidence of RIHD is declining, but it still must be carefully investigated to minimize the mortality and morbidity of patients with thoracic malignancies after RT treatment. Effective methods for preventing RIMF involve a decrease in the direct radiation dose in the heart, and early screening and diagnosis. Medications remain as a useful adjunct for preventing or treating RIMF. This review mainly discusses the cellular and molecular mechanisms underlying RIMF, and new therapeutic drugs that can potentially be developed from this knowledge.

Gene therapy and cell therapy for the management of radiation damages to healthy tissues: Rationale and early results

Nowadays, ionizing radiations have numerous applications, especially in medicine for diagnosis and therapy. Pharmacological radioprotection aims at increasing detoxification of free radicals. Radiomitigation aims at improving survival and proliferation of damaged cells. Both strategies are essential research area, as non-contained radiation can lead to harmful effects. Some advances allowing the comprehension of normal tissue injury mechanisms, and the discovery of related predictive biomarkers, have led to developing several highly promising radioprotector or radiomitigator drugs. Next to these drugs, a growing interest does exist for biotherapy in this field, including gene therapy and cell therapy through mesenchymal stem cells. In this review article, we provide an overview of the management of radiation damages to healthy tissues via gene or cell therapy in the context of radiotherapy. The early management aims at preventing the occurrence of these damages before exposure or just after exposure. The late management offers promises in the reversion of constituted late damages following irradiation.

An evaluation of the effect of bortezomib on radiation-induced urinary bladder dysfunction

PURPOSE

The urinary bladder is one major organ at risk in radiotherapy of pelvic malignancies. The radiation response manifests in early and chronic changes in bladder function. These are based on inflammatory effects and changes in urothelial cell function and proliferation. This study evaluates the effect of bortezomib as an anti-proliferative and anti-inflammatory compound in an established mouse bladder model. The early radiation-induced bladder dysfunction in the mouse occurs in two phases during the first month after irradiation (phase I: day 0-15, phase II: days 16-30).

MATERIALS AND METHODS

Daily bortezomib injections (0.02 mg/ml, subcutaneously) were administered between days 0-15 or 15-30 in separate groups. Single graded radiation doses were administered in five dose groups. Cystometry was carried out before (individual control) and during the first month after irradiation. When bladder capacity was decreased by ≥50%, mice were considered as responders. Statistical analysis was performed by the SPSS software version 24.

RESULTS

Daily bortezomib injections between days 0-15 resulted in a significant decrease in responders for phase I. There was no significant effect with daily bortezomib injections between days 16-30.

CONCLUSION

Two separate waves of acute radiation-induced urinary bladder dysfunction have distinct mechanisms that need further biological studies.

Selective Heart Irradiation Induces Cardiac Overexpression of the Pro-hypertrophic miR-212

Background: A deleterious, late-onset side effect of thoracic radiotherapy is the development of radiation-induced heart disease (RIHD). It covers a spectrum of cardiac pathology including also heart failure with preserved ejection fraction (HFpEF) characterized by left ventricular hypertrophy (LVH) and diastolic dysfunction. MicroRNA-212 (miR-212) is a crucial regulator of pathologic LVH via FOXO3-mediated pathways in pressure-overload-induced heart failure. We aimed to investigate whether miR-212 and its selected hypertrophy-associated targets play a role in the development of RIHD. Methods: RIHD was induced by selective heart irradiation (50 Gy) in a clinically relevant rat model. One, three, and nineteen weeks after selective heart irradiation, transthoracic echocardiography was performed to monitor cardiac morphology and function. Cardiomyocyte hypertrophy and fibrosis were assessed by histology at week 19. qRT-PCR was performed to measure the gene expression changes of miR-212 and forkhead box O3 (FOXO3) in all follow-up time points. The cardiac transcript level of other selected hypertrophy-associated targets of miR-212 including extracellular signal-regulated kinase 2 (ERK2), myocyte enhancer factor 2a (MEF2a), AMP-activated protein kinase, (AMPK), heat shock protein 40 (HSP40), sirtuin 1, (SIRT1), calcineurin A-alpha and phosphatase and tensin homolog (PTEN) were also measured at week 19. Cardiac expression of FOXO3 and phospho-FOXO3 were investigated at the protein level by Western blot at week 19. Results: In RIHD, diastolic dysfunction was present at every time point. Septal hypertrophy developed at week 3 and a marked LVH with interstitial fibrosis developed at week 19 in the irradiated hearts. In RIHD, cardiac miR-212 was overexpressed at week 3 and 19, and FOXO3 was repressed at the mRNA level only at week 19. In contrast, the total FOXO3 protein level failed to decrease in response to heart irradiation at week 19. Other selected hypertrophy-associated target genes failed to change at the mRNA level in RIHD at week 19. Conclusions: LVH in RIHD was associated with cardiac overexpression of miR-212. However, miR-212 seems to play a role in the development of LVH via FOXO3-independent mechanisms in RIHD. As a central regulator of pathologic remodeling, miR-212 might become a novel target for RIHD-induced LVH and heart failure.

Radiation-Induced Lung Injury: Assessment and Management

Radiation-induced lung injury (RILI) encompasses any lung toxicity induced by radiation therapy (RT) and manifests acutely as radiation pneumonitis and chronically as radiation pulmonary fibrosis. Because most patients with thoracic and breast malignancies are expected to undergo RT in their lifetime, many with curative intent, the population at risk is significant. Furthermore, indications for thoracic RT are expanding given the advent of stereotactic body radiation therapy (SBRT) or stereotactic ablative radiotherapy (SABR) for early-stage lung cancer in nonsurgical candidates as well as oligometastatic pulmonary disease from any solid tumor. Fortunately, the incidence of serious pulmonary complications from RT has decreased secondary to advances in radiation delivery techniques. Understanding the temporal relationship between RT and injury as well as the patient, disease, and radiation factors that help distinguish RILI from other etiologies is necessary to prevent misdiagnosis. Although treatment of acute pneumonitis is dependent on clinical severity and typically responds completely to corticosteroids, accurately diagnosing and identifying patients who may progress to fibrosis is challenging. Current research advances include high-precision radiation techniques, an improved understanding of the molecular basis of RILI, the development of small and large animal models, and the identification of candidate drugs for prevention and treatment.

Long-term neurocognitive benefits of FLASH radiotherapy driven by reduced reactive oxygen species

Here, we highlight the potential translational benefits of delivering FLASH radiotherapy using ultra-high dose rates (>100 Gy⋅s-1). Compared with conventional dose-rate (CONV; 0.07-0.1 Gy⋅s-1) modalities, we showed that FLASH did not cause radiation-induced deficits in learning and memory in mice. Moreover, 6 months after exposure, CONV caused permanent alterations in neurocognitive end points, whereas FLASH did not induce behaviors characteristic of anxiety and depression and did not impair extinction memory. Mechanistic investigations showed that increasing the oxygen tension in the brain through carbogen breathing reversed the neuroprotective effects of FLASH, while radiochemical studies confirmed that FLASH produced lower levels of the toxic reactive oxygen species hydrogen peroxide. In addition, FLASH did not induce neuroinflammation, a process described as oxidative stress-dependent, and was also associated with a marked preservation of neuronal morphology and dendritic spine density. The remarkable normal tissue sparing afforded by FLASH may someday provide heretofore unrealized opportunities for dose escalation to the tumor bed, capabilities that promise to hasten the translation of this groundbreaking irradiation modality into clinical practice.

Nipple Reconstruction: A Novel Triple Flap Design

Supplemental Digital Content is available in the text.

Background:

Restoring the nipple–areola complex completes the breast reconstructive process. Local flaps are often used for the nipple reconstruction; however, the number of techniques indicates the lack of a superior design. The aims of this study were to test the feasibility of a new triple flap design for nipple reconstruction and to evaluate complication rate and nipple projection.

Methods:

From November 2015 to November 2018, we performed the triple flap nipple reconstruction guided by a template for preoperative mark-up. Patients were followed up postoperatively to evaluate healing and signs of complications including wound dehiscence, infection, and flap necrosis, and nipple projection. The areola was tattooed 3 months postoperatively.

Results:

Twenty-six nipple reconstructions were successfully performed in 22 women. Four nipple reconstructions (15%) were performed in irradiated tissue. One reconstruction had a superficial infection, while there were no cases of wound dehiscence or flap necrosis. Three nipple reconstructions (12%) experienced prolonged healing that did not require intervention. None of these reconstructions had received radiation therapy. The nipple projection was 7.3 mm (range 6–9 mm) at the time of surgery and 3.1 mm (range 0–6 mm), 2.5 mm (range 2–3 mm), and 1.6 mm (range 0–3 mm) at follow-up of 3, 6, and 12 months, respectively.

Conclusions:

We present the new triple flap design for nipple reconstruction guided by a template for mark-up. The preliminary results indicate a low complication rate in both irradiated and nonirradiated patients while sustaining the projection over time remains to be a challenge.

Suplatast tosilate reduces radiation-induced lung injury in mice through suppression of oxidative stress

PURPOSE

Although radiotherapy is important in the treatment of malignant thoracic tumors, it has harmful effects on healthy tissues. We previously showed that suplatast tosilate, an anti-allergic agent, scavenged reactive oxygen species (ROS), including hydroxyl radicals. Because ROS-mediated oxidative stress is involved in radiation-induced lung injury, we hypothesized that suplatast tosilate could reduce radiation-induced lung injury via suppression of oxidative stress.

METHODS AND MATERIALS

Murine alveolar epithelial cells were irradiated with or without a medium containing suplatast tosilate in vitro to determine whether the agent had cytoprotective effects against radiation-induced injury. On the other hand, the thoracic region of C57BL/6 mice was exposed to a single irradiation dose of 15 Gy and the effects of suplatast tosilate were determined by a histological evaluation and assessment of the following parameters: cell number and inflammatory cytokine levels in bronchoalveolar lavage fluid, and oxidative stress markers and hydroxyproline content in pulmonary tissues.

RESULTS

Suplatast tosilate protected murine alveolar epithelial cells in vitro from irradiation-induced inhibition of cell proliferation, which was accompanied by the suppression of intracellular ROS and DNA double-strand breaks induced by irradiation. Oxidative stress markers and the levels of inflammatory and fibrogenic cytokines were upregulated in irradiated murine lungs in vivo. Suplatast tosilate suppressed both oxidative stress markers and the levels of cytokines, which resulted in reduced pulmonary fibrosis and clearly improved the survival rate after irradiation.

CONCLUSIONS

These findings demonstrate that suplatast tosilate could be a useful lung-protective agent that acts via suppression of oxidative stress associated with thoracic radiotherapy.

Huangqi Shengmai Yin Protects against Radiation-Induced Cardiac Fibrosis Injury by Regulating the TGF-β1/Smads and MMPs

Background

Radiation-induced heart damage is considered to be a progressive process of fibrosis. Emerging evidence has indicated that the Smads and matrix metalloproteinases (MMPs)/tissue inhibitors of MMPs (TIMP) may be involved in radiation-induced cardiac fibrosis (RICF) by regulating the activation of TGF-β1 signaling pathway. Based on this, the present study was undertaken to characterize the effect of Huangqi Shengmai Yin (HSY) on RICF in a rat model.

Methods

Precardiac region of rats was irradiated with 25 Gy X-rays, and their myocardial pathology scores in terms of injury and collagen volume fraction (CVF) and the expression levels of fibrotic molecules were detected.

Results

The pathology scores and CVF in myocardial tissue increased after irradiation, and the expression of TGF-β1, Col1, and Col3 increased. This change indicated that such irradiation promoted the fibrosis damage in rat hearts. The damage was accompanied by an increase in the expression of Smad 2, Smad3, Smad4, and MMP14 and a decrease in the expression of Smad 7 and TIMP1. Administration of HSY weakened the RICF by decreasing pathology score and CVF and decreased the expression of TGF-β1, Col1, and Col3 in irradiated rat hearts. In addition, Smad2, Smad3, Smad4, and MMP14 were downregulated, while Smad 7 and TIMP1 were upregulated during intervention with HSY.

Conclusions

The involvement of the TGF-β1/Smads and MMPs/TIMP system in RICF was confirmed. This study demonstrated, for the first time, that HSY attenuates the effects of RICF in a rat model. The effect HSY was found to be closely related to the TGF-β1/Smads signaling pathway and MMPs system. These results suggest that HSY is a prospective drug for clinical treatment of RICF.

Application of Manual Therapy for Dysphagia in Head and Neck Cancer Patients: A Preliminary National Survey of Treatment Trends and Adverse Events

BACKGROUND

Radiation-associated dysphagia is a common and debilitating consequence of treatment for head and neck cancer (HNC). Since commonly employed dysphagia therapy programs for HNC patients still lack authoritative efficacy, some speech-language pathologists (SLPs) have started employing manual therapy (MT) techniques in an attempt to prevent or rehabilitate dysphagia in this patient population. However, exceptionally little is known about the use of MT in this patient population.

OBJECTIVES

The purpose of this study was to describe practice patterns as well as the rate, type, and severity of adverse events associated with SLP provision of MT to HNC patients.

METHODS

An Internet-based questionnaire geared toward SLPs who practice MT was developed and sent to SLPs practicing in the United States, 3 times, through 3 national listservs (American Speech Language Hearing Association [ASHA] Special Interest Division 13, ASHA Special Interest Division 3, and University of Iowa Voiceserv), over the course of 4 weeks.

RESULTS

Of the 255 respondents, 116 (45.5%) performed MT on HNC patients. Of these 116 SLPs, 27.6% provided proactive MT during radiation, 62.1% provided 1 to 2 sessions per week, and 94.8% prescribed a MT home program. The rate, type, and severity of reported adverse events were similar between HNC and non-HNC patients.

CONCLUSION

This preliminary survey demonstrated that SLPs provide MT to HNC patients during and after cancer treatment, and that reported adverse events paralleled those experienced by noncancer patients. However, these results should be taken with caution, and a well-designed prospective study is needed to formally establish the safety and the preliminary efficacy of this novel clinical intervention.

Stroma in normal and cancer wound healing

It is currently believed that stroma, the connective framework of biological tissues, plays a central role in normal wound healing and in cancer. In both these contexts, stromal cellular components such as activated fibroblasts interact with complex protein networks that include growth factors, structural protein or proteinases in order to initiate and sustain an extensive remodelling process. However, although this process is usually spatially and temporally self-limited, it is unregulated in the case of cancer and leads to uncontrolled cell proliferation and invasion within tissues, metastasis and therapeutic resistance. In this review, we outline the role of stroma in normal healing, cancer and post radiotherapy, with a particular focus on the crosstalk between normal or cancer cells and fibroblasts. Understanding these mechanisms is particularly important as several stromal components have been proposed as potential therapeutic targets.

Targeting the Immunomodulatory CD73/Adenosine System to Improve the Therapeutic Gain of Radiotherapy

Extracellular adenosine is a potent endogenous immunosuppressive mediator critical to the maintenance of homeostasis in various normal tissues including the lung. Adenosine is either released from stressed or injured cells or generated from extracellular adenine nucleotides by the concerted action of the ectoenzymes ectoapyrase (CD39) and 5′ ectonucleotidase (CD73) that catabolize ATP to adenosine. An acute CD73-dependent increase of adenosine in normal tissues mostly exerts tissue protective functions whereas chronically increased adenosine-levels in tissues exposed to DNA damaging chemotherapy or radiotherapy promote pathologic remodeling processes and fibrosis for example in the skin and the lung. Importantly, cancer cells also express CD73 and high CD73 expression in the tumor tissue has been linked to poor overall survival and recurrence free survival in patients suffering from breast and ovarian cancer. CD73 and adenosine support growth-promoting neovascularization, metastasis, and survival in cancer cells. In addition, adenosine can promote tumor intrinsic or therapy-induced immune escape by various mechanisms that dampen the immune system. Consequently, modulating CD73 or cancer-derived adenosine in the tumor microenvironment emerges as an attractive novel therapeutic strategy to limit tumor progression, improve antitumor immune responses, avoid therapy-induced immune deviation, and potentially limit normal tissue toxicity. However, the role of CD73/adenosine signaling in the tumor and normal tissue responses to radiotherapy and its use as therapeutic target to improve the outcome of radiotherapy approaches is less understood. The present review will highlight the dual role of CD73 and adenosine in tumor and tissue responses to radiotherapy with a special focus to the lung. It will also discuss the potential benefits and risks of pharmacologic modulation of the CD73/adenosine system to increase the therapeutic gain of radiotherapy or combined radioimmunotherapy in cancer treatment.

Prognostic Impact of Perineural Invasion in Rectal Cancer After Neoadjuvant Chemoradiotherapy

BACKGROUND

Perineural invasion (PNI) has emerged as an important factor related to colorectal cancer spread; however, the impact of neoadjuvant chemoradiotherapy (nCRT) on PNI remains unclear. Herein, we investigated the prognostic value of PNI, along with lymphovascular invasion (LVI), in rectal cancer patients treated with nCRT.

METHODS

This single-center observational study of pathologic variables, including PNI and LVI, analyzed 1411 invasive rectal cancer patients (965 and 446 patients treated with primary resection and nCRT, respectively).

RESULTS

The overall detection rates of LVI and PNI were 16.7 and 28.8%, respectively. The incidence of LVI was significantly lower in patients treated with nCRT (8.1 vs. 20.6%, P < .001); this was confirmed by multivariate analysis. However, PNI was not affected by nCRT (with nCRT 28.3% vs. without nCRT 29.1%, P = .786). In the 446 patients with nCRT, multivariate analysis revealed that PNI was an independent prognostic factor for both disease-free survival (DFS) and overall survival (OS). For the prediction of both 5-year DFS and OS, the C-index for the combinations of T-stage with the PNI (TPNI) system showed favorable result, especially in patients with a total number of harvested lymph nodes <8.

CONCLUSION

PNI is a meaningful prognostic factor for rectal cancer patients treated with nCRT, especially when <8 lymph nodes are harvested. The lack of influence of nCRT on the PNI incidence suggests that residual tumor cells with PNI are more radioresistant or biologically aggressive than those without.

Blockade of Aquaporin 4 Inhibits Irradiation-Induced Pulmonary Inflammation and Modulates Macrophage Polarization in Mice

To investigate the effects of aquaporin 4 (AQP4) inhibitor in irradiation-induced pulmonary inflammation in mice. A single dose of 75 Gy was delivered to the left lung of mice to induce radiation pneumonitis. For inhibition of AQP4, 200 mg/kg of TGN-020 was administered i.p. one time per 2 days post-irradiation. Blockade of AQP4 with TGN-020 resulted in the inhibition of inflammatory cell infiltration and the downregulation of inflammatory cytokines (IL-6, IL-17, and TGF-β), chemokines (MIP1a and MCP1), fibrosis-related (Col3al and Fn1), and M2 macrophage marker (Arg1) post-irradiation. Immunofluorescence staining indicated that there was significant fewer M2 macrophage infiltration in the irradiated lung tissues from mice treated with TGN-020. Additionally, depletion of macrophages with liposome clodronate resulted in alleviated lung injury induced by irradiation. Furthermore, adoptive transfer of M1 or M2 macrophages into clodronate-treated mice was performed. The results showed that the administration of M2 macrophages fully reversed the clodronate-induced beneficial effect on inflammation score, thickness, and fibrosis. However, transfer of M1 macrophages only impacted the inflammation score and thickness and did not affect lung fibrosis. AQP4 blockade alleviated the development and severity of irradiated lung damage. This was associated with attenuated infiltration of inflammatory cell, decreased production of pro-inflammatory cytokines, and inhibited activation of M2 macrophages.

The effects of Radix Angelica Sinensis and Radix Hedysari ultrafiltration extract on X-irradiation-induced myocardial fibrosis in rats

Radix Angelica Sinensis and Radix Hedysari are traditional Chinese medicines that are used for preventing and treating various diseases. This study aimed to investigate the effect and possible underlying mechanisms of Radix Angelica Sinensis and Radix Hedysari ultrafiltration extract (RAS-RH) on X-irradiation-induced cardiac fibrosis in rats. Our data demonstrated that (a) a single dose of total body irradiation (TBI) at 8 Gy resulted in cardiac fibrosis, whereas the control hearts exhibited less collagen and fibrosis. RAS-RH mitigated these morphological injuries. (b) TBI resulted in an increase in the serum levels of transforming growth factor β1 (TGF-β1) and troponin-I (TnI). RAS-RH inhibited the release of TBI-induced serum TGF-β1 and the TnI levels. (c) TBI inhibited the apoptosis of primary rat cardiac fibroblasts, whereas RAS-RH induced the apoptosis of primary rat cardiac fibroblasts after X- irradiation. (d) TBI resulted in an increase in the expression of osteopontin (OPN), c-fos, c-jun, miRNA-21 and collagen1α (COL1α) in primary rat cardiac fibroblasts, and RAS-RH mitigated the TBI-induced increased expression of OPN, c-jun, miRNA-21 and COL1α. In conclusion, these results demonstrate that RAS-RH exerts antifibrotic effects possibly through inducing the apoptosis of fibroblasts, inhibiting the release of serum TGF-β1, reducing the levels of serum TnI and reducing the expression of OPN, c-jun, miRNA-21 and COL1α. Therefore, RAS-RH may potentially be developed as a medical countermeasure for the mitigation of radiation-induced myocardial fibrosis.

Pravastatin Reverses Established Radiation-Induced Cutaneous and Subcutaneous Fibrosis in Patients With Head and Neck Cancer: Results of the Biology-Driven Phase 2 Clinical Trial Pravacur

PURPOSE

The "PRAVACUR" phase 2 trial (NCT01268202) assessed the efficacy of pravastatin as an antifibrotic agent in patients with established cutaneous and subcutaneous radiation-induced fibrosis (RIF) after head and neck squamous cell carcinoma (HNSCC) radiation therapy and/or radiochemotherapy.

METHODS AND MATERIALS

The main inclusion criteria were: NSCC in remission, grade ≥2 cutaneous and subcutaneous neck RIF (National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0), and no current treatment with statins or fibrates. Patients received pravastatin 40 mg/d for 12 months. The primary endpoint was reduction of RIF thickness by more than 30% at 12 months, as measured by cutaneous high-frequency ultrasonography. Secondary endpoints included RIF severity reduction, pravastatin tolerance, and quality of life.

RESULTS

Sixty patients with grade 2 (n = 37), grade 3 (n = 22), or grade 4 (n = 1) RIF were enrolled from February 2011 to April 2016. The mean interval between RIF diagnosis and pravastatin initiation was 17.1 months. Pravastatin was stopped before 11 months of treatment in 18 patients (because of grade ≥2 adverse events related to pravastatin in 8 patients [13%]). In the 40 patients in whom pravastatin efficacy was assessed by high-frequency ultrasonography at baseline and at 12 months of treatment, a reduction of RIF thickness ≥30% was observed in 15 of 42 patients (35.7%; 95% confidence interval, 21.6%-52.0%). At the 12-month clinical evaluation, RIF severity was decreased in 50% of patients (n = 21; 95% confidence interval, 34.2%-65.8%), and the patients' self-perception, mood state, and social functioning were significantly improved. Pravastatin was well tolerated, with a very low occurrence of grade 3 toxicities (myalgia, n = 1) and grade 2 toxicities (myalgia/arthralgia or esophagitis, n = 3).

CONCLUSIONS

This phase 2 prospective study supports the notion of radioinduced fibrosis reversibility. It showed that pravastatin (40 mg/d for 12 months) is an efficient antifibrotic agent in patients with grade ≥2 cutaneous and subcutaneous fibrosis after HNSCC radiation therapy.

Fat Chance: The Rejuvenation of Irradiated Skin

Radiotherapy (RT) helps cure and palliate thousands of patients with a range of malignant diseases. A major drawback, however, is the collateral damage done to tissues surrounding the tumor in the radiation field. The skin and subcutaneous tissue are among the most severely affected regions. Immediately following RT, the skin may be inflamed, hyperemic, and can form ulcers. With time, the dermis becomes progressively indurated. These acute and chronic changes cause substantial patient morbidity, yet there are few effective treatment modalities able to reduce radiodermatitis. Fat grafting is increasingly recognized as a tool able to reverse the fibrotic skin changes and rejuvenate the irradiated skin. This review outlines the current progress toward describing and understanding the cellular and molecular effects of fat grafting in irradiated skin. Identification of the key factors involved in the pathophysiology of fibrosis following RT will inform therapeutic interventions to enhance its beneficial effects.

TGFβ Blockade Enhances Radiotherapy Abscopal Efficacy Effects in Combination with Anti-PD1 and Anti-CD137 Immunostimulatory Monoclonal Antibodies

Radiotherapy can be synergistically combined with immunotherapy in mouse models, extending its efficacious effects outside of the irradiated field (abscopal effects). We previously reported that a regimen encompassing local radiotherapy in combination with anti-CD137 plus anti-PD-1 mAbs achieves potent abscopal effects against syngeneic transplanted murine tumors up to a certain tumor size. Knowing that TGFβ expression or activation increases in irradiated tissues, we tested whether TGFβ blockade may further enhance abscopal effects in conjunction with the anti-PD-1 plus anti-CD137 mAb combination. Indeed, TGFβ blockade with 1D11, a TGFβ-neutralizing mAb, markedly enhanced abscopal effects and overall treatment efficacy against subcutaneous tumors of either 4T1 breast cancer cells or large MC38 colorectal tumors. Increases in CD8 T cells infiltrating the nonirradiated lesion were documented upon combined treatment, which intensely expressed Granzyme-B as an indicator of cytotoxic effector capability. Interestingly, tumor tissue but not healthy tissue irradiation results in the presence of higher concentrations of TGFβ in the nonirradiated contralateral tumor that showed smad2/3 phosphorylation increases in infiltrating CD8 T cells. In conclusion, radiotherapy-induced TGFβ hampers abscopal efficacy even upon combination with a potent immunotherapy regimen. Therefore, TGFβ blockade in combination with radioimmunotherapy results in greater efficacy.

Modeling and multiscale characterization of the quantitative imaging based fibrosis index reveals pathophysiological, transcriptome and proteomic correlates of lung fibrosis induced by fractionated irradiation

Pulmonary fibrosis represents a leading cause of morbidity and mortality worldwide. Therapy induced lung fibrosis constitutes a pivotal dose‐limiting side effect of radiotherapy and other anticancer agents. We aimed to develop objective criteria for assessment of fibrosis and discover pathophysiological and molecular correlates of lung fibrosis as a function of fractionated whole thoracic irradiation. Dose–response series of fractionated irradiation was utilized to develop a non‐invasive and quantitative measure for the degree of fibrosis – the fibrosis index (FI). The correlation of FI with histopathology, blood‐gas, transcriptome and proteome responses of the lung tissue was analyzed. Macrophages infiltration and polarization was assessed by immunohistochemistry. Fibrosis development followed a slow kinetic with maximum lung fibrosis levels detected at 24‐week post radiation insult. FI favorably correlated with radiation dose and surrogates of lung fibrosis i.e., enhanced pro‐inflammatory response, tissue remodeling and extracellular matrix deposition. The loss of lung architecture correlated with decreased epithelial marker, loss of microvascular integrity with decreased endothelial and elevated mesenchymal markers. Lung fibrosis was further attributed to a switch of the inflammatory state toward a macrophage/T‐helper cell type 2‐like (M2/Th2) polarized phenotype. Together, the multiscale characterization of FI in radiation‐induced lung fibrosis (RILF) model identified pathophysiological, transcriptional and proteomic correlates of fibrosis. Pathological immune response and endothelial/epithelial to mesenchymal transition were discovered as critical events governing lung tissue remodeling. FI will be instrumental for deciphering the molecular mechanisms governing lung fibrosis and discovery of novel targets for treatment of this devastating disease with an unmet medical need.

What's new?

The development of fibrosis scar tissue in the lungs is a dose‐limiting effect of radiotherapy for thoracic malignancies. Molecular mechanisms driving radiation‐induced lung fibrosis (RILF), however, remain unclear. In this study, a fibrosis index (FI) was devised to quantitatively detect spatial and temporal kinetics of lung fibrosis development. Multi‐scale characterization of FI uncovered mechanisms governing lung fibrosis, including perturbation of immune balance and microvascular integrity. Radiation dose and FI were correlated with an inflammatory switch toward a macrophage/T‐helper cell type 2‐like polarized phenotype. The findings open the way for further mechanistic study and the discovery of therapeutic targets for RILF.

The impact of time after radiation treatment on dysphagia in patients with head and neck cancer enrolled in a swallowing therapy program

BACKGROUND

Swallowing dysfunction after radiotherapy (RT) for head and neck cancer can be devastating. A randomized control trial compared swallow exercises versus exercise plus neuromuscular electrical stimulation therapy and found no overall difference in outcomes.

METHODS

Quality of life (QOL), diet, and swallowing variables collected at discrete intervals on 117 patients were reanalyzed to test the hypothesis that shorter time between the completion of radiotherapy and beginning of the swallowing therapy program yielded improved outcomes.

RESULTS

At baseline, subjects < 1 year post radiation had significantly better function than subjects >2 years post RT in several measures. Over the therapy program, the early group showed significant improvement in diet and QOL. Swallowing physiologic variables showed no difference between groups.

CONCLUSION

Beginning a swallowing therapy program within 1 year of completion of radiotherapy demonstrates more consistent improvement in QOL and diet performance compared to later periods.

Prognostic and Added Value of Echocardiographic Strain for Prediction of Adverse Outcomes in Patients with Locally Advanced Non-Small Cell Lung Cancer after Radiotherapy

Radiotherapy (RT) is potentially related to cardiotoxicity, which may partially offset the benefits of cancer treatment. We sought to evaluate subclinical myocardial dysfunction using speckle tracking echocardiography after RT and to explore the associations between early cardiac effects and adverse outcomes in patients with non-small cell lung cancer (NSCLC). In total, 112 patients with stage III NSCLC who were scheduled to receive RT were prospectively recruited. A reduction in global longitudinal strain (GLS) was observed immediately after RT and at 6 mo after RT (6 m-RT). In multivariable analysis, the percentage change in GLS from baseline to 6 mo (ΔGLS%_{6 m-RT}) (hazard ratio = 1.202, 95% confidence interval: 1.095-1.320, p < 0.001) was an independent predictor of all-cause mortality. Based on receiver operating characteristic curve analysis, ΔGLS%_{6 m-RT} ≥13.65% had 65.9% sensitivity and 85.2% specificity for predicting mortality in NSCLC patients (area under the curve = 0.784, 95% confidence interval: 0.692-0.876, p < 0.001). These findings should encourage physicians to perform echocardiography early after RT.

Soy Isoflavones Protect Normal Tissues While Enhancing Radiation Responses

Soy isoflavones have demonstrated chemopreventive and anticancer properties in epidemiology and biological studies, in addition to their function as antioxidants in prevention of cardiovascular disease. We have explored the potential of soy isoflavones, as a safe biological approach, to enhance the efficacy of radiotherapy for local tumor control and limit normal tissue damage in solid tumors. This review presents studies investigating the interaction between soy isoflavones and radiation in different malignancies, including prostate cancer, renal cell carcinoma, and nonsmall cell lung cancer. Soy isoflavones were found to be potent sensitizers of cancer cells to radiation causing increased cell killing in vitro in human tumor cell lines and greater tumor inhibition in vivo in preclinical orthotopic murine tumor models. In the course of these studies, radioprotection of normal tissues and organs in the field of radiation was observed both in a clinical trial for prostate cancer and in preclinical models. The mechanisms of radiosensitization and radioprotection mediated by soy isoflavones are discussed and emphasize the role of soy isoflavones in increasing radiation effect on tumor and mitigating inflammatory responses induced by radiation in normal tissues. Soy isoflavones could be used as a safe, nontoxic complementary strategy that simultaneously increases radiation effectiveness on the malignancy while reducing damage in normal tissues in the field of radiation.

Combining Radiotherapy and Immunotherapy in Lung Cancer: Can We Expect Limitations Due to Altered Normal Tissue Toxicity?

In recent decades, technical advances in surgery and radiotherapy, as well as breakthroughs in the knowledge on cancer biology, have helped to substantially improve the standard of cancer care with respect to overall response rates, progression-free survival, and the quality of life of cancer patients. In this context, immunotherapy is thought to have revolutionized the standard of care for cancer patients in the long term. For example, immunotherapy approaches such as immune checkpoint blockade are currently increasingly being used in cancer treatment, either alone or in combination with chemotherapy or radiotherapy, and there is hope from the first clinical trials that the appropriate integration of immunotherapy into standard care will raise the success rates of cancer therapy to a new level. Nevertheless, successful cancer therapy remains a major challenge, particularly in tumors with either pronounced resistance to chemotherapy and radiation treatment, a high risk of normal tissue complications, or both, as in lung cancer. Chemotherapy, radiotherapy and immunotherapy have the capacity to evoke adverse effects in normal tissues when administered alone. However, therapy concepts are usually highly complex, and it is still not clear if combining immunotherapy with radio(chemo)therapy will increase the risk of normal tissue complications, in particular since normal tissue toxicity induced by chemotherapy and radiotherapy can involve immunologic processes. Unfortunately, no reliable biomarkers are available so far that are suited to predict the unique normal tissue sensitivity of a given patient to a given treatment. Consequently, clinical trials combining radiotherapy and immunotherapy are attracting major attention, not only regarding efficacy, but also with regard to safety. In the present review, we summarize the current knowledge of radiation-induced and immunotherapy-induced effects in tumor and normal tissue of the lung, and discuss the potential limitations of combined radio-immunotherapy in lung cancer with a focus on the suspected risk for enhanced acute and chronic normal tissue toxicity.

Haemostatic radiation therapy for a bleeding intraductal papillary neoplasm of the biliary tree

Haemostatic radiation was effectively used as a novel rescue therapy in a 60-year-old man who presented with recurrent melaena refractory to all conventional medical and surgical measures. He needed multiple transfusions and was diagnosed to be bleeding from an intraductal papillary biliary neoplasm which was not amenable to surgical resection in view of the background liver disease. He received conventional radiation therapy (RT) of a dose of 3 Gy per fraction for 3 consecutive days after which he stabilised. After cessation of the RT, he did not require transfusion for the next 2 months. His quality of life improved and it gave us time to evaluate for other definitive measures.

Effect of Pregabalin on Radiotherapy-Related Neuropathic Pain in Patients With Head and Neck Cancer: A Randomized Controlled Trial

PURPOSE

Neuropathic pain is an unavoidable treatment-related adverse event among patients with head and neck cancer who are undergoing radiotherapy. We aimed to test the efficacy and safety of pregabalin versus placebo in the treatment of radiotherapy-related neuropathic pain.

PATIENTS AND METHODS

This randomized, double-blind, placebo-controlled trial was conducted in four centers in China. Eligible patients with a mean pain intensity score of 4 or more on an 11-point numeric rating scale were randomly assigned to receive either active treatment with a flexible dose of pregabalin or placebo for 16 weeks. The primary efficacy outcome was pain reduction measured on the numeric rating scale.

RESULT

There were 128 patients who received treatment as randomly assigned. Pain intensity reduction was 2.44 in the pregabalin arm and 1.58 in the placebo arm at week 16, yielding an adjusted mean difference of 0.87 (95% CI, 0.30 to 1.44; P = .003). In the pregabalin arm, 38 patients (59.4%) achieved at least 30% pain relief versus 21 (32.8%) in the placebo arm ( P = .006). Nineteen patients (29.7%) in the pregabalin group and five (7.8%) in the placebo group achieved 50% or greater pain relief ( P = .003). Total scores on the Profile of Mood States-Short Form, pain severity and functional interference of Brief Pain Inventory-Short Form, as well as the physiology and psychology domain of the WHO Quality of Life-BREF all were reduced significantly at week 16 in patients who received pregabalin compared with those who received placebo. There was no significant difference ( P = .29) in the incidence of experiencing at least one adverse event in the pregabalin arm (n = 35; 54.7%) versus the placebo arm (n = 29; 45.3%).

CONCLUSION

Patients treated with pregabalin with radiotherapy-related neuropathic pain had greater pain alleviation, better mood states, and higher quality of life compared with patients in the placebo group, with a good tolerability.

Early Changes in Cardiovascular Biomarkers with Contemporary Thoracic Radiation Therapy for Breast Cancer, Lung Cancer, and Lymphoma

PURPOSE

We characterized the early changes in cardiovascular biomarkers with contemporary thoracic radiation therapy (RT) and evaluated their associations with radiation dose-volume metrics including mean heart dose (MHD), V5, and V30.

METHODS AND MATERIALS

In a prospective longitudinal study of 87 patients with breast cancer, lung cancer, or mediastinal lymphoma treated with photon or proton thoracic RT, blood samples were obtained pre-RT and after completion of RT (median, 20 days; interquartile range [IQR], 1-35). High-sensitivity cardiac troponin T, N-terminal pro-B-type natriuretic peptide, placental growth factor (PIGF), and growth differentiation factor 15 (GDF-15) were measured. Associations between MHD, V5 and V30, and biomarker levels and associations between echocardiography-derived measures of cardiac function and biomarker levels were assessed in multivariable linear regression models. Analyses were performed according to the following subgroups: (1) breast cancer alone and (2) lung cancer and lymphoma combined.

RESULTS

The median (IQR) estimates of MHD ranged from 1.3 Gy (0.9-2.4) in breast cancer (n = 60) to 6.8 Gy (5.4-10.2) in mediastinal lymphoma (n = 14) and 8.4 Gy (6.7-16.1) in lung cancer (n = 13) patients (P < .001). There were no significant increases in biomarker levels from pre-RT to post-RT in breast cancer. In lung cancer/lymphoma, PIGF increased from a median (IQR) of 20 ng/L (16-26) to 22 ng/L (16-30) (P = .005), and GDF-15 increased from 1171 ng/L (755-2493) to 1887 ng/L (903-3763) (P = .006). MHD, V5, and V30 were significantly associated with post-RT PIGF and GDF-15 levels in multivariable models. Changes in biomarkers were not significantly associated with changes in echocardiography-derived measures of cardiac function.

CONCLUSION

Contemporary thoracic RT induces acute abnormalities in vascular and inflammatory biomarkers that are associated with radiation dose-volume metrics, particularly in lung cancer and mediastinal lymphoma. Long-term follow-up studies are needed to determine the impact of these changes on the development of overt cardiac disease.

Cytokines and radiation-induced pulmonary injuries

Radiation therapy is one of the most common treatment strategies for thorax malignancies. One of the considerable limitations of this therapy is its toxicity to normal tissue. The lung is the major dose-limiting organ for radiotherapy. That is because ionizing radiation produces reactive oxygen species that induce lesions, and not only is tumor tissue damaged, but overwhelming inflammatory lung damage can occur in the alveolar epithelium and capillary endothelium. This damage may result in radiation-induced pneumonitis and/or fibrosis. While describing the lung response to irradiation generally, the main focus of this review is on cytokines and their roles and functions within the individual stages. We discuss the relationship between radiation and cytokines and their direct and indirect effects on the formation and development of radiation injuries. Although this topic has been intensively studied and discussed for years, we still do not completely understand the roles of cytokines. Experimental data on cytokine involvement are fragmented across a large number of experimental studies; hence, the need for this review of the current knowledge. Cytokines are considered not only as molecular factors involved in the signaling network in pathological processes, but also for their diagnostic potential. A concentrated effort has been made to identify the significant immune system proteins showing positive correlation between serum levels and tissue damages. Elucidating the correlations between the extent and nature of radiation-induced pulmonary injuries and the levels of one or more key cytokines that initiate and control those damages may improve the efficacy of radiotherapy in cancer treatment and ultimately the well-being of patients.

Decreases in TGF-β1 and PDGF levels are associated with echocardiographic changes during adjuvant radiotherapy for breast cancer

BACKGROUND

Radiation-induced heart disease is mainly caused by activation of the fibrotic process. Transforming growth factor-beta 1 (TGF-β1) and platelet-derived growth factor (PDGF) are pro-fibrotic mediators. The aim of our study was to evaluate the behavior of TGF-β1 and PDGF during adjuvant radiotherapy (RT) for breast cancer and the association of these cytokines with echocardiographic changes.

METHODS

Our study included 73 women with early-stage breast cancer or ductal carcinoma in situ (DCIS) receiving post-operative RT but not chemotherapy. TGF-β1 and PDGF levels in serum samples taken before and on the last day of RT were measured by an enzyme-linked immunosorbent assay. Echocardiography was also performed at same time points. Patients were grouped according to a ≥ 15% worsening in tricuspid annular plane systolic excursion (TAPSE) and pericardium calibrated integrated backscatter (cIBS).

RESULTS

In all patients, the median TGF-β1 decreased from 25.0 (IQR 21.1-30.3) ng/ml to 23.6 (IQR 19.6-26.8) ng/ml (p = 0.003), and the median PDGF decreased from 18.0 (IQR 13.7-22.7) ng/ml to 15.6 (IQR 12.7-19.5) ng/ml (p < 0.001). The baseline TGF-β1, 30.7 (IQR 26.0-35.9) ng/l vs. 23.4 (IQR 20.1-27.3) ng/l (p < 0.001), and PDGF, 21.5. (IQR 15.7-31.2) ng/l vs. 16.9. (IQR 13.0-21.2) ng/ml, were higher in patients with a ≥ 15% decrease in TAPSE than in patients with a < 15% decrease. In patients with a ≥ 15% decrease in TAPSE, the median TGF-β1 decreased to 24.7 (IQR 20.0-29.8) ng/ml (p < 0.001), and the median PDGF decreased to 16.7 (IQR 12.9-20.9) ng/ml (p < 0.001). The patients with a < 15% decrease had stable TGF-β1 (p = 0.104), but PDGF decreased to 15.1 (IQR 12.5-18.6), p = 0.005. The patients with a ≥ 15% increase in cIBS exhibited a decrease in TGF-β1 from 26.0 (IQR 21.7-29.7) to 22.5 (IQR 16.6.-26.7) ng/ml, p < 0.001, and a decrease in PDGF from 19.8 (IQR 14.6-25.9) to 15.7 (IQR 12.8-20.2) ng/ml, p < 0.001. In patients with a < 15% increase, TGF-β1 and PDGF did not change significantly, p = 0.149 and p = 0.053, respectively.

CONCLUSION

We observed a decrease in TGF-β1 and PDGF levels during adjuvant RT for breast cancer. Echocardiographic changes, namely, in TAPSE and cIBS, were associated with a greater decrease in TGF-β1 and PDGF levels. Longer follow-up times will show whether these changes observed during RT translate into increased cardiovascular morbidity.

Upregulation of Plasminogen Activator Inhibitor-1 in Irradiated Recipient Arteries and Veins from Free Tissue Transfer Reconstruction in Cancer Patients

Background

Clinical studies have shown that radiotherapy can induce vascular disease at the site of exposure but is usually not clinically evident until years after treatment. We have studied irradiated human arteries and veins to better understand the underlying biology in search of future treatments. The aim was to investigate whether radiotherapy contributed to a sustained expression of plasminogen activator inhibitor-1 (PAI-1) in human arteries and veins.

Methods

Irradiated arteries and veins were harvested, together with unirradiated control vessels, from patients undergoing free tissue transfer reconstruction at a median time of 90 weeks [5–650] following radiation exposure. Differential gene expression of PAI-1 was analysed, together with immunohistochemistry (IHC) and immunofluorescence (IF).

Results

PAI-1 gene expression was increased in both arteries (p = 0.012) and veins (p < 0.001) in irradiated compared to unirradiated control vessels. IHC and IF indicated that cells expressing PAI-1 were located in the adventitia of both arteries and veins and colocalized with cells positive for CD68, CD45, and α-SMA in arteries and with CD45 and α-SMA in veins.

Conclusion

The current study shows a sustained upregulation of PAI-1 in both arteries and veins after exposure to ionizing radiation, indicating a chronic inflammation mainly in the adventitia. We believe that the results contribute to further understanding of radiation-induced vascular disease, where targeting PAI-1 may be a potential treatment.

Established and novel pathophysiological mechanisms of pericardial injury and constrictive pericarditis

This review article aims to: (1) discern from the literature the immune and inflammatory processes occurring in the pericardium following injury; and (2) to delve into the molecular mechanisms which may play a role in the progression to constrictive pericarditis. Pericarditis arises as a result of a wide spectrum of pathologies of both infectious and non-infectious aetiology, which lead to various degrees of fibrogenesis. Current understanding of the sequence of molecular events leading to pathological manifestations of constrictive pericarditis is poor. The identification of key mechanisms and pathways common to most fibrotic events in the pericardium can aid in the design and development of novel interventions for the prevention and management of constriction. We have identified through this review various cellular events and signalling cascades which are likely to contribute to the pathological fibrotic phenotype. An initial classical pattern of inflammation arises as a result of insult to the pericardium and can exacerbate into an exaggerated or prolonged inflammatory state. Whilst the implication of major drivers of inflammation and fibrosis such as tumour necrosis factor and transforming growth factor β were foreseeable, the identification of pericardial deregulation of other mediators (basic fibroblast growth factor, galectin-3 and the tetrapeptide Ac-SDKP) provides important avenues for further research.

Development of an easy-to-handle murine model for the characterization of radiation-induced gross and molecular changes in skin

BACKGROUND

Radiation-induced skin injury is a dose-limiting complication of radiotherapy. To investigate this problem and to develop a framework for making decisions on treatment and dose prescription, a murine model of radiation-induced skin injury was developed.

METHODS

The dorsal skin of the mice was isolated, and irradiation was applied at single doses of 15, 30, and 50 Gy. The mice were followed for 12 weeks with serial photography and laser Doppler analysis. Sequential skin biopsy samples were obtained and subjected to a histological analysis, immunostaining against transforming growth factor beta (TGF-β), and Western blotting with Wnt-3 and β-catenin. Increases in the levels of TGF-β, Wnt, and β-catenin were detected after irradiation.

RESULTS

All tested radiation doses caused progressive dermal thickening and fibrosis. The cause of this process, however, may not be radiation alone, as the natural course of wound healing may elicit a similar response. The latent appearance of molecular and histological markers that induce fibrosis in the 15 Gy group without causing apparent gross skin injuries indicates that 15 Gy is an appropriate dose for characterizing the effects of chronic irradiation alone. Thus, this model best mimics the patterns of injury that occur in human subjects.

CONCLUSIONS

This animal model can be used to elucidate the gross and molecular changes that occur in radiation-induced skin injury and provides an effective platform for studying this adverse effect without complicating the process of wound healing.

Radiation-induced muscle fibrosis rat model: establishment and valuation

Background

Lack of animal model of radiation induced muscle fibrosis, this study aimed to establish such a model by using 90 Gy single dose irradiation to mimic clinical relevance and also to explore the potential post-irradiation regenerative mechanism.

Methods

SD rats were randomly divided into dose investigation groups and time gradient groups. Group1–6 were irradiated with a single dose of 65Gy, 70Gy, 75Gy, 80Gy, 85Gy and 90Gy respectively, and the degree of rectus femoris fibrosis in the irradiated area was detected at 4 weeks after irradiation. Group 7–9 were irradiated with a single dose of 90Gy, and the results were detected 1, 2, 4, and 8 weeks after irradiation. Then the general condition of rats was recorded. Masson staining was used to detect muscle fibrosis. The ultrastructure of muscles was observed by electron microscope, and the expression changes of satellite cell proliferation and differentiation related genes were detected by quantitative real-time-PCR.

Results

A single dose of 90Gy irradiation could cause muscle fibrosis in rats. As time goes on, the severity of muscle fibrosis and the expression of TGF- β1 increased. Significant swelling of mitochondria, myofilament disarrangement and dissolution, obvious endothelial cell swelling, increased vascular permeability, decrease of blood cell, deposition of fibrosis tissue around the vessel could be found compared with the control group. At around the 4th week, the expressions of Pax7, Myf5, MyoD, MyoG, Mrf4 increased.

Conclusion

Irradiation of 90Gy can successfully establish the rat model of radiation-induced muscle fibrosis. This model demonstrated that regenerative process was initiated by the irradiation only at an early stage, which can serve a suitable model for investigating regenerative therapy for post-radiation muscle fibrosis.

Deferoxamine Preconditioning of Irradiated Tissue Improves Perfusion and Fat Graft Retention

BACKGROUND

Radiation therapy is a mainstay in the treatment of many malignancies, but collateral damage to surrounding tissue, with resultant hypovascularity, fibrosis, and atrophy, can be difficult to reconstruct. Fat grafting has been shown to improve the quality of irradiated skin, but volume retention of the graft is significantly decreased. Deferoxamine is a U.S. Food and Drug Administration-approved iron-chelating medication for acute iron intoxication and chronic iron overload that has also been shown to increase angiogenesis. The present study evaluates the effects of deferoxamine treatment on irradiated skin and subsequent fat graft volume retention.

METHODS

Mice underwent irradiation to the scalp followed by treatment with deferoxamine or saline and perfusion and were analyzed using laser Doppler analysis. Human fat grafts were then placed beneath the scalp and retention was also followed up to 8 weeks radiographically. Finally, histologic evaluation of overlying skin was performed to evaluate the effects of deferoxamine preconditioning.

RESULTS

Treatment with deferoxamine resulted in significantly increased perfusion, as demonstrated by laser Doppler analysis and CD31 immunofluorescent staining (p < 0.05). Increased dermal thickness and collagen content secondary to irradiation, however, were not affected by deferoxamine (p > 0.05). Importantly, fat graft volume retention was significantly increased when the irradiated recipient site was preconditioned with deferoxamine (p < 0.05).

CONCLUSIONS

The authors' results demonstrated increased perfusion with deferoxamine treatment, which was also associated with improved fat graft volume retention. Preconditioning with deferoxamine may thus enhance fat graft outcomes for soft-tissue reconstruction following radiation therapy.

Quantitative assessment of radiation-induced changes of bladder and rectum collagen structure using optical methods

The objective of the study is the quantitative analysis of the dose-time dependences of changes occurring in collagen of bladder and rectum after gamma-irradiation using optical methods [nonlinear microscopy in a second harmonic generation (SHG) detection regime and cross-polarization optical coherence tomography (CP OCT)]. For quantitative assessment of the collagen structure, regions of interest on the SHG-images of two-dimensional (2-D) distribution of SHG signal intensity of collagen were chosen in the submucosa. The mean SHG signal intensity and its standard deviation were calculated by ImageJ 1.39p (NIH). For quantitative analysis of CP OCT data, an integral depolarization factor (IDF) was calculated. Quantitative calculation of the SHG signal intensity and the IDF can provide additional information about the processes of the collagen radiation-induced degradation and subsequent remodeling. High positive correlation between the mean SHG signal intensity and the mean IDF of bladder and rectum demonstrates that CP OCT can be used as an "optical biopsy" in the grading of collagen radiation damage.

Expanding the therapeutic index of radiation therapy by normal tissue protection

Normal tissue damages induced by radiation therapy remain dose-limiting factors in radiation oncology and this is still true despite recent advances in treatment planning and delivery of image-guided radiation therapy. Additionally, as the number of long-term cancer survivors increases, unacceptable complications emerge and dramatically reduce the patients' quality of life. This means that patients and clinicians expect discovery of new options for the therapeutic management of radiation-induced complications. Over the past four decades, research has enhanced our understanding of the pathophysiological, cellular and molecular processes governing normal tissue toxicity. Those processes are complex and involve the cross-talk between the various cells of a tissue, including fibroblasts, endothelial, immune and epithelial cells as well as soluble paracrine factors including growth factors and proteases. We will review the translatable pharmacological approaches that have been developed to prevent, mitigate, or reverse radiation injuries based upon the targeting of cellular and signalling pathways. We will summarize the different steps of the research strategy, from the definition of initial biological hypotheses to preclinical studies and clinical translation. We will also see how novel research and therapeutic hypotheses emerge along the way as well as briefly highlight innovative approaches based upon novel radiotherapy delivery procedures.

Osteoradionecrosis of the Skull Base in Nasopharyngeal Carcinoma: Incidence and Risk Factors

PURPOSE

Nasopharyngeal carcinoma (NPC) is a type of malignancy with a high prevalence in southern China and Southeast Asia. The primary treatment modality is radiation therapy (RT). Osteoradionecrosis (ORN) of the skull base remains one of the most serious complications after RT, affecting survival time and quality of life. Thus far, skull base ORN has been seldom reported and can be difficult to distinguish and easy to misdiagnose. In this retrospective study, we report the incidence of skull base ORN and analyze its associated factors in an attempt to decrease the occurrence of ORN.

METHODS AND MATERIALS

From January 2001 to December 2012, a total of 1348 patients who received diagnoses of NPC received 1 course of RT. Complete medical records were reviewed, and the patients were examined by magnetic resonance imaging and nasopharyngeal endoscopy during follow-up after primary treatment. Patients with other tumors of the head and neck, a history of RT, failure to complete RT, and those lost to follow-up were excluded. Treatment was delivered with external beam RT using standard linear accelerators.

RESULTS

A total of 1348 patients with NPC were enrolled in this study after 1 course of RT; among these patients, 14 received diagnoses of skull base ORN. The incidence of skull base ORN was 1.04%. The average latency interval from the completion of RT to the diagnosis of skull base ORN was 45.57 months. Skull base ORN after 1 course of RT was associated with the T stage; total radiation dose to the nasopharynx, including the skull base in the radiation field; and anemia.

CONCLUSIONS

The occurrence of skull base ORN was associated with primary tumors with advanced T stages, high doses of nasopharynx RT, and radiation fields that included the skull base. These factors may be used as predictors for the incidence of skull base ORN.

Inhibition Mechanism of Acellular Dermal Matrix on Capsule Formation in Expander-Implant Breast Reconstruction After Postmastectomy Radiotherapy

BACKGROUND

Capsular contracture is one of the most common complications of expander-implant breast reconstruction. Recently, clinical reports have shown that use of an acellular dermal matrix (ADM) to cover breast implants decreases incidence of capsular contracture, but the underlying mechanism is unclear. Here, we examine how ADM reduces capsular formation in expander-implant breast reconstruction and identify cellular and molecular mechanisms of ADM-mediated reduction of capsular contracture in nonirradiated and irradiated patients.

METHODS

Thirty patients who underwent immediate two-stage implant-based breast reconstruction were included; 15 received radiotherapy. While the tissue expander was changed to permanent silicone implant, biopsies of the subpectoral capsule and ADM capsule were performed. Capsule thickness, immunohistochemistry of α-smooth muscle actin (αSMA), vimentin, CD31, F4/80 expression, αSMA and CD31 coexpression, and relative gene expression levels of transforming growth factor (TGF)-β1 and platelet-derived growth factor (PDGF)-B were investigated.

RESULTS

Irradiated submuscular capsules were thicker than nonirradiated submuscular capsules, but the thickness of ADM capsules did not significantly differ between nonirradiated and irradiated groups. Levels of myofibroblasts, fibroblasts, vascularity, EndoMT, and macrophages were significantly lower in ADM capsules than in submuscular capsules. With the exception of EndoMT, all others were increased in irradiated submuscular capsules compared with nonirradiated submuscular capsule, while none significantly differed between nonirradiated and irradiated ADM capsules.

CONCLUSIONS

Use of ADM reduced myofibroblasts, vascularity, fibroblasts, and EndoMT in capsule tissues. Moreover, ADM use decreased macrophages, a key regulator of tissue fibrosis, as well as TGF-β1 and PDGF-B expression. We hope that these results provide basic concepts important for prevention of capsular contracture.

Triptolide mitigates radiation-induced pneumonitis via inhibition of alveolar macrophages and related inflammatory molecules

Ionizing radiation-induced pulmonary injury is a major limitation of radiotherapy for thoracic tumors. We have demonstrated that triptolide (TPL) could alleviate IR-induced pneumonia and pulmonary fibrosis. In this study, we explored the underlying mechanism by which TPL mitigates the effects of radiotoxicity. The results showed that:

(1) Alveolar macrophages (AMs) were the primary inflammatory cells infiltrating irradiated lung tissues and were maintained at a high level for at least 17 days, which TPL could reduce by inhibiting of the production of macrophage inflammatory protein-2 (MIP-2) and its receptor CXCR2.

(2) Stimulated by the co-cultured irradiated lung epithelium, AMs produced a panel of inflammative molecules (IMs), such as cytokines (TNF-α, IL-6, IL-1α, IL-1β) and chemokines (MIP-2, MCP-1, LIX). TPL-treated AMs could reduce the production of these IMs. Meanwhile, AMs isolated from irradiated lung tissue secreted significantly high levels of IMs, which could be dramatically reduced by TPL.

(3) TPL suppressed the phagocytosis of AMs as well as ROS production.

Our results indicate that TPL mitigates radiation-induced pulmonary inflammation through the inhibition of the infiltration, IM secretion, and phagocytosis of AMs.