Quercetin inhibits radiation-induced skin fibrosis

Highly efficient prevention of radiation dermatitis using a PEGylated superoxide dismutase dissolving microneedle patch

PEGylated superoxide dismutase (PEG-SOD) is commonly used as a cytoprotective agent in radiotherapy. However, its effectiveness in preventing radiation dermatitis is limited owing to its poor skin permeability. To address this issue, a PEG-SOD-loaded dissolving microneedle (PSMN) patch was developed to effectively prevent radiation dermatitis. Initially, PSMN patches were fabricated using a template mold method with polyvinylpyrrolidone K90 as the matrix material. PSMNs exhibited a conical shape with adequate mechanical strength to penetrate the stratum corneum. More than 90 % of PEG-SOD was released from the PSMN patches within 30 min. Notably, the PSMN patches showed a significantly higher drug skin permeation than the PEG-SOD solutions, with a 500-fold increase. In silico simulations and experiments on skin pharmacokinetics confirmed that PSMN patches enhanced drug permeation and skin absorption, in contrast to PEG-SOD solutions. More importantly, PSMN patches efficiently mitigated ionizing radiation-induced skin damage, accelerated the healing process of radiation-affected skin tissues, and exhibited highly effective radioprotective activity for DNA in the skin tissue. Therefore, PSMN patches are promising topical remedy for the prevention of radiation dermatitis.

Fabrication of poly (lactic-co-glycolic acid)/gelatin electro spun nanofiber patch containing CaCO3/SiO2 nanocomposite and quercetin for accelerated diabetic wound healing

An open wound or sore on the bottom of the foot caused by diabetes is known as a diabetic foot ulcer. Preventive measures are essential, including consistent foot care and glycemic management. The dangers associated with diabetic foot ulcers can be reduced via early identification and timely treatment. The risk of foot ulcers and limb amputation increases with age and duration of diabetes. Quercetin contains anti-inflammatory and antioxidant properties. Furthermore, the calcium carbonate/silica (CaCO3/SiO2) nanocomposite has a good anti-inflammatory property due to the presence of calcium, which will aid in wound healing. As a result, combining quercetin (plant based anti-inflammatory drug) and CaCO3/SiO2 nanocomposite will boost the wound healing rate. We have synthesized CaCO3/SiO2 nanocomposite in sol-gel method and characterized using XRD, FTIR and TEM. Cell line tests and the MTT assay revealed that the PLGA/gelatin/CaCO3/SiO2/quercetin patch enhanced the proliferation of cells. Its anti-bacterial efficacy against four major bacterial strains often found in wound locations, as well as its water retention, make it an ideal material for diabetic wound healing. In-vivo trials confirms the enhanced diabetic wound healing potential of the patch.

Tissue fibrosis induced by radiotherapy: current understanding of the molecular mechanisms, diagnosis and therapeutic advances

Cancer remains the leading cause of death around the world. In cancer treatment, over 50% of cancer patients receive radiotherapy alone or in multimodal combinations with other therapies. One of the adverse consequences after radiation exposure is the occurrence of radiation-induced tissue fibrosis (RIF), which is characterized by the abnormal activation of myofibroblasts and the excessive accumulation of extracellular matrix. This phenotype can manifest in multiple organs, such as lung, skin, liver and kidney. In-depth studies on the mechanisms of radiation-induced fibrosis have shown that a variety of extracellular signals such as immune cells and abnormal release of cytokines, and intracellular signals such as cGAS/STING, oxidative stress response, metabolic reprogramming and proteasome pathway activation are involved in the activation of myofibroblasts. Tissue fibrosis is extremely harmful to patients' health and requires early diagnosis. In addition to traditional serum markers, histologic and imaging tests, the diagnostic potential of nuclear medicine techniques is emerging. Anti-inflammatory and antioxidant therapies are the traditional treatments for radiation-induced fibrosis. Recently, some promising therapeutic strategies have emerged, such as stem cell therapy and targeted therapies. However, incomplete knowledge of the mechanisms hinders the treatment of this disease. Here, we also highlight the potential mechanistic, diagnostic and therapeutic directions of radiation-induced fibrosis.

Quercetin and Related Analogs as Therapeutics to Promote Tissue Repair

Quercetin is a polyphenol of the flavonoid class of secondary metabolites that is widely distributed in the plant kingdom. Quercetin has been found to exhibit potent bioactivity in the areas of wound healing, neuroprotection, and anti-aging research. Naturally found in highly glycosylated forms, aglycone quercetin has low solubility in aqueous environments, which has heavily limited its clinical applications. To improve the stability and bioavailability of quercetin, efforts have been made to chemically modify quercetin and related flavonoids so as to improve aqueous solubility while retaining bioactivity. In this review, we provide an updated overview of the biological properties of quercetin and proposed mechanisms of actions in the context of wound healing and aging. We also provide a description of recent developments in synthetic approaches to improve the solubility and stability of quercetin and related analogs for therapeutic applications. Further research in these areas is expected to enable translational applications to improve ocular wound healing and tissue repair.

Connection between Radiation-Regulating Functions of Natural Products and miRNAs Targeting Radiomodulation and Exosome Biogenesis

Exosomes are cell-derived membranous structures primarily involved in the delivery of the payload to the recipient cells, and they play central roles in carcinogenesis and metastasis. Radiotherapy is a common cancer treatment that occasionally generates exosomal miRNA-associated modulation to regulate the therapeutic anticancer function and side effects. Combining radiotherapy and natural products may modulate the radioprotective and radiosensitizing responses of non-cancer and cancer cells, but there is a knowledge gap regarding the connection of this combined treatment with exosomal miRNAs and their downstream targets for radiation and exosome biogenesis. This review focuses on radioprotective natural products in terms of their impacts on exosomal miRNAs to target radiation-modulating and exosome biogenesis (secretion and assembly) genes. Several natural products have individually demonstrated radioprotective and miRNA-modulating effects. However, the impact of natural-product-modulated miRNAs on radiation response and exosome biogenesis remains unclear. In this review, by searching through PubMed/Google Scholar, available reports on potential functions that show radioprotection for non-cancer tissues and radiosensitization for cancer among these natural-product-modulated miRNAs were assessed. Next, by accessing the miRNA database (miRDB), the predicted targets of the radiation- and exosome biogenesis-modulating genes from the Gene Ontology database (MGI) were retrieved bioinformatically based on these miRNAs. Moreover, the target-centric analysis showed that several natural products share the same miRNAs and targets to regulate radiation response and exosome biogenesis. As a result, the miRNA-radiomodulation (radioprotection and radiosensitization)-exosome biogenesis axis in regard to natural-product-mediated radiotherapeutic effects is well organized. This review focuses on natural products and their regulating effects on miRNAs to assess the potential impacts of radiomodulation and exosome biogenesis for both the radiosensitization of cancer cells and the radioprotection of non-cancer cells.

Pharmacological Therapies for Connective Tissue Fibrosis in Orthopaedics

Fibrosis is a common and debilitating pathological process that affects many organ systems and contributes to connective tissue disorders in orthopaedics. Tendons heal after acute and chronic injury through a process of fibrovascular scar tissue formation, and soft tissue joint capsules can be affected after traumatic joint injury, leading to arthrofibrosis. Although the precise underlying mechanisms are still being elucidated, fibrosis is thought to be a consequence of dysregulated immune and cytokine signaling that leads to myofibroblast activation and proliferation and subsequent excessive collagen deposition. Current treatments for connective tissue fibrosis include physical therapy and surgery, but there are no therapies that directly target the underlying cellular and molecular mechanisms of fibrosis. Many pharmacological agents have been used to successfully target fibrosis in other tissues and organ systems and thus are a promising treatment option to fill this gap. However, limited evidence is available to guide the use of these agents in musculoskeletal connective tissues. This article provides an overview of pharmacological therapies that have potential to treat connective tissue fibrosis in patients with musculoskeletal conditions, along with the current supporting evidence and future uses of each therapy.

Exploring Natural Products as Radioprotective Agents for Cancer Therapy: Mechanisms, Challenges, and Opportunities

Radiotherapy is an important cancer treatment. However, in addition to killing tumor cells, radiotherapy causes damage to the surrounding cells and is toxic to normal tissues. Therefore, an effective radioprotective agent that prevents the deleterious effects of ionizing radiation is required. Numerous synthetic substances have been shown to have clear radioprotective effects. However, most of these have not been translated for use in clinical applications due to their high toxicity and side effects. Many medicinal plants have been shown to exhibit various biological activities, including antioxidant, anti-inflammatory, and anticancer activities. In recent years, new agents obtained from natural products have been investigated by radioprotection researchers, due to their abundance of sources, high efficiency, and low toxicity. In this review, we summarize the mechanisms underlying the radioprotective effects of natural products, including ROS scavenging, promotion of DNA damage repair, anti-inflammatory effects, and the inhibition of cell death signaling pathways. In addition, we systematically review natural products with radioprotective properties, including polyphenols, polysaccharides, alkaloids, and saponins. Specifically, we discuss the polyphenols apigenin, genistein, epigallocatechin gallate, quercetin, resveratrol, and curcumin; the polysaccharides astragalus, schisandra, and Hohenbuehelia serotina; the saponins ginsenosides and acanthopanax senticosus; and the alkaloids matrine, ligustrazine, and β-carboline. However, further optimization through structural modification, improved extraction and purification methods, and clinical trials are needed before clinical translation. With a deeper understanding of the radioprotective mechanisms involved and the development of high-throughput screening methods, natural products could become promising novel radioprotective agents.

Polyphenols as Potential Protectors against Radiation-Induced Adverse Effects in Patients with Thoracic Cancer

Radiotherapy is one of the standard treatment approaches used against thoracic cancers, occasionally combined with chemotherapy, immunotherapy and molecular targeted therapy. However, these cancers are often not highly sensitive to standard of care treatments, making the use of high dose radiotherapy necessary, which is linked with high rates of radiation-induced adverse effects in healthy tissues of the thorax. These tissues remain therefore dose-limiting factors in radiation oncology despite recent technological advances in treatment planning and delivery of irradiation. Polyphenols are metabolites found in plants that have been suggested to improve the therapeutic window by sensitizing the tumor to radiotherapy, while simultaneously protecting normal cells from therapy-induced damage by preventing DNA damage, as well as having anti-oxidant, anti-inflammatory or immunomodulatory properties. This review focuses on the radioprotective effect of polyphenols and the molecular mechanisms underlying these effects in the normal tissue, especially in the lung, heart and esophagus.

Huanglian Jiedu plaster ameliorated X-ray-induced radiation dermatitis injury by inhibiting HMGB1-mediated macrophage-inflammatory interaction

ETHNOPHARMACOLOGICAL RELEVANCE

Huanglian Jiedu plaster (HJP) is a kind of Chinese patent medicine that contains four medicinal plants. It has been clinically proven to be beneficial for the treatment of tumor-associated radiation dermatitis. However, the underlying mechanism of HJP on radiation dermatitis remains unclear.

AIM OF THE STUDY

This study aims to investigate the therapeutic effect of HJP on X-ray-induced radiation dermatitis, and how HJP improves the inflammatory response and skin damage of radiation dermatitis.

MATERIALS AND METHODS

In this study, We selected a case of esophageal cancer as a clinical demonstration of the efficacy of radiation dermatitis. The patient received a total radiation dose of 7000cGY, and treatment by HJP for 14 days.RD mouse models were established through continuous irradiation with X-ray (800cGY) on the right hind limb of mice for 5 days, and the treatment group mice was applied HJP to the irradiated skin for 15 days from modeling. An inflammatory cellular model was induced through irradiation with X-ray (100cGY) in JB6 cells and a co-culture system of JB6 cell and macrophage was established to examine the effect and mechanism of HJP on the inflammatory interaction of these two cells. The activation of HMGB1-TLR4-NF-κB signaling pathway, and the levels of epidermal injury related factors and inflammatory cytokins were subsequently detected.

RESULTS

The results showed that HJP can significantly alleviate X-ray-induced skin injury, inhibiting skin inflammation and reducing the expression of inflammatory cytokins (IL-1β, IL-6, TNF-α) and epidermal damage related factors (Integrin β1, CXCL9 and Cytokeratin17), as well as significantly down-regulated the protein level of HMGB1 (a key DAMPs factor) in vivo and in vitro. Cell co-culture experiments demonstrated that HMGB1 released from X-ray-induced JB6 cells can promote inflammatory response of macrophage, which then feedback aggravate epithelial cell damage, notably, HJP can significantly improve radiation skin lesion by inhibiting HMGB1-mediated inflammatory interaction between epithelial cells and macrophages.

CONCLUSION

In summary, these findings indicated the role of HJP in the treatment of RD by inhibiting the inflammatory interaction between macrophage and JB6 cells mediated by HMGB1, which may provide a reliable therapeutic method for RD. Furthermore, HMGB1 may be an effective target for HJP to inhibit inflammation and ameliorate skin damage in RD.

Protective Role of Natural Compounds under Radiation-Induced Injury

In recent years, evidence has shown the potential therapeutic effects of different natural compounds for the prevention and treatment of radiotherapy-induced mucositis (RIOM). RIOM represents one of the most frequent side effects associated with anti-neoplastic treatments affecting patients' quality of life and treatment response due to radiation therapy discontinuation. The innate radio-protective ability of natural products obtained from plants is in part due to the numerous antioxidants possessed as a part of their normal secondary metabolic processes. However, oxygen presence is a key point for radiation efficacy on cancer cells. The aim of this review is to describe the most recent evidence on radiation-induced injury and the emerging protective role of natural compounds in preventing and treating this specific damage without compromising treatment efficacy.

A study of the molecular mechanism of quercetin and dasatinib combination as senolytic in alleviating age-related and kidney diseases

Aging is a significant risk factor for the majority of prevalent human illnesses. The chance of having severe chronic conditions grows dramatically with advancing age. Indeed, more than 90% of people over 65 get at least one chronic disease, including diabetes, heart disease, malignancy, memory loss, and kidney disease, whereas more than 70% have two or more of these ailments. Mouse and human aging lead to increased senescent cells and decreased klotho concentrations. Mice lacking the protein α-klotho show faster aging, similar to human aging. α-Klotho upregulation extends life and slows or suppresses the onset of many age-related illnesses and kidney diseases. Like the consequences of α-klotho deficiency, senescent cell accumulation is linked to tissue dysfunction in various organs and multiple age-related kidney diseases. In addition, α-klotho and cell senescence are negatively and presumably mechanistically linked. Earlier research has demonstrated that klotho exerts its protective effects in age-related and kidney disease by interacting with Wnt ligands, serving as an endogenous antagonist of Wnt/β-catenin signaling. In addition, decreasing senescent cell burden with senolytics, a class of drugs that remove senescent cells selectively and extend the life span of mice. In this work, we are studying the molecular mechanism of the combination of quercetin and dasatinib as senolytic in easing age-related chronic renal illness by altering the level of klotho/Wnt/β-catenin. PRACTICAL APPLICATIONS: There is an inverse relationship between the onset and the development of age-related disorders and cellular senescence and Klotho. Earlier attempts to suppress transforming growth factor-beta 1 (TGF-β1) in kidney disease with anti-TGF-β1 antibodies were ineffective, and this should be kept in mind. Senolytic medications may benefit from targeting senescent cells, which enhances the protective factor α-klotho. In addition, our study provides a unique, translationally feasible route for creating orally active small compounds to enhance α-klotho, which may also be a valuable biomarker for age-related kidney disease. Additionally, other aspects of aging can be affected by senolytics, such as limiting age-related mitochondrial dysfunction, lowering inflammation and fibrosis, blunting reactive oxygen species (ROS) generation, decreasing deoxyribonucleic acid (DNA) damage, and reinforcing insulin sensitivity. Senolytic agents have been shown to increase adipose progenitor and cardiac progenitor cell activity in aging animals and animals with cellular senescence-related diseases, such as heart, brain, and kidney disease.

Nuclear and Radiological Emergencies: Biological Effects, Countermeasures and Biodosimetry

Atomic and radiological crises can be caused by accidents, military activities, terrorist assaults involving atomic installations, the explosion of nuclear devices, or the utilization of concealed radiation exposure devices. Direct damage is caused when radiation interacts directly with cellular components. Indirect effects are mainly caused by the generation of reactive oxygen species due to radiolysis of water molecules. Acute and persistent oxidative stress associates to radiation-induced biological damages. Biological impacts of atomic radiation exposure can be deterministic (in a period range a posteriori of the event and because of destructive tissue/organ harm) or stochastic (irregular, for example cell mutation related pathologies and heritable infections). Potential countermeasures according to a specific scenario require considering basic issues, e.g., the type of radiation, people directly affected and first responders, range of doses received and whether the exposure or contamination has affected the total body or is partial. This review focuses on available medical countermeasures (radioprotectors, radiomitigators, radionuclide scavengers), biodosimetry (biological and biophysical techniques that can be quantitatively correlated with the magnitude of the radiation dose received), and strategies to implement the response to an accidental radiation exposure. In the case of large-scale atomic or radiological events, the most ideal choice for triage, dose assessment and victim classification, is the utilization of global biodosimetry networks, in combination with the automation of strategies based on modular platforms.

2-Methoxyestradiol Inhibits Radiation-Induced Skin Injuries

Radiation-induced skin injury (RISI) is a main side effect of radiotherapy for cancer patients, with vascular damage being a common pathogenesis of acute and chronic RISI. Despite the severity of RISI, there are few treatments for it that are in clinical use. 2-Methoxyestradiol (2-ME) has been reported to regulate the radiation-induced vascular endothelial-to-mesenchymal transition. Thus, we investigated 2-ME as a potent anti-cancer and hypoxia-inducible factor 1 alpha (HIF-1α) inhibitor drug that prevents RISI by targeting HIF-1α. 2-ME treatment prior to and post irradiation inhibited RISI on the skin of C57/BL6 mice. 2-ME also reduced radiation-induced inflammation, skin thickness, and vascular fibrosis. In particular, post-treatment with 2-ME after irradiation repaired the damaged vessels on the irradiated dermal skin, inhibiting endothelial HIF-1α expression. In addition to the increase in vascular density, post-treatment with 2-ME showed fibrotic changes in residual vessels with SMA⁺CD31⁺ on the irradiated skin. Furthermore, 2-ME significantly inhibited fibrotic changes and accumulated DNA damage in irradiated human dermal microvascular endothelial cells. Therefore, we suggest that 2-ME may be a potent therapeutic agent for RISI.

Cutaneous and local radiation injuries

The threat of a large-scale radiological or nuclear (R/N) incident looms in the present-day climate, as noted most recently in an editorial in Scientific American (March 2021). These large-scale incidents are infrequent but affect large numbers of people. Smaller-scale R/N incidents occur more often, affecting smaller numbers of people. There is more awareness of acute radiation syndrome (ARS) in the medical community; however, ionising radiation-induced injuries to the skin are much less understood. This article will provide an overview of radiation-induced injuries to the skin, deeper tissues, and organs. The history and nomenclature; types and causes of injuries; pathophysiology; evaluation and diagnosis; current medical management; and current research of the evaluation and management are presented. Cutaneous radiation injuries (CRI) or local radiation injuries (LRI) may lead to cutaneous radiation syndrome, a sub-syndrome of ARS. These injuries may occur from exposure to radioactive particles suspended in the environment (air, soil, water) after a nuclear detonation or an improvised nuclear detonation (IND), a nuclear power plant incident, or an encounter with a radioactive dispersal or exposure device. These incidents may also result in a radiation-combined injury; a chemical, thermal, or traumatic injury, with radiation exposure. Skin injuries from medical diagnostic and therapeutic imaging, medical misadministration of nuclear medicine or radiotherapy, occupational exposures (including research) to radioactive sources are more common but are not the focus of this manuscript. Diagnosis and evaluation of injuries are based on the scenario, clinical picture, and dosimetry, and may be assisted through advanced imaging techniques. Research-based multidisciplinary therapies, both in the laboratory and clinical trial environments, hold promise for future medical management. Great progress is being made in recognising the extent of injuries, understanding their pathophysiology, as well as diagnosis and management; however, research gaps still exist.

Quercetin Prevents Radiation-Induced Oral Mucositis by Upregulating BMI-1

Radiation-induced oral mucositis is a major adverse event of radiotherapy. Severe oral mucositis may cause unwanted interruption in radiotherapy and reduce long-term survival in cancer patients receiving radiotherapy, but until now, there have been no effective options for preventing radiation-induced oral mucositis. Quercetin is a flavonoid that is widely found in food species and has anti-inflammatory, antioxidant, and anticancer activities. In this study, we investigated a new role of quercetin in preventing radiation-induced oral mucositis. Quercetin exerted preventive effects against radiation-induced oral mucositis induced by single-dose (25 Gy) ionizing radiation or fractionated ionizing radiation (8 Gy × 3) in C57BL/6 mice and maintained the proliferation ability of basal epithelial cells. Quercetin pretreatment alleviated reactive oxygen species generation, NF-κB pathway activation, and downstream proinflammatory cytokine production and reduced DNA double-strand breaks and cellular senescence induced by ionizing radiation. Quercetin also upregulated BMI-1 expression in oral epithelial cells and promoted ulcer repair. In addition, quercetin exerted similar radioprotective effects in irradiated primary cultured normal human keratinocytes, reduced reactive oxygen species generation and proinflammatory cytokine release, and promoted DNA double-strand break repair and wound healing by upregulating the expression of BMI-1, which is a polycomb group protein. Thus, quercetin can block multiple pathological processes of radiation-induced oral mucositis by targeting BMI-1 and may be a potential treatment option for preventing radiation-induced oral mucositis.

Radioprotective Role of Natural Polyphenols: From Sources to Mechanisms

The identification and development of radioprotective agents has emerged as a subject matter of research during recent years due to the growing usage of ionizing radiation in different areas of human life. Previous work on synthetic radioprotectors has achieved limited progress because of the numerous issues associated with toxicity. Compounds extracted from plants have potential to serve as lead candidates for developing ideal radioprotectors due to their low cost, safety and selectivity. Polyphenols are the most abundant and commonly dispersed group of biologically active molecules possessing broad range of pharmacological activities. Polyphenols have displayed efficacy for radioprotection during various investigations and can be administered at high doses with lesser toxicity. Detoxification of free radicals, modulating inflammatory responses, DNA repair, stimulation of hematopoietic recovery, and immune functions are the main mechanisms for radiation protection with polyphenols. Epicatechin, epigallocatechin-3-gallate, apigenin, caffeic acid phenylethylester, and silibinin provide cytoprotection together with the suppression of many pro-inflammatory cytokines owing to their free radical scavenging, anti-oxidant, and anti-inflammatory properties. Curcumin, resveratrol, quercetin, gallic acid, and rutin's radioprotective properties are regulated primarily by direct or indirect decline in cellular stress. Thus, polyphenols may serve as potential candidates for radioprotection in the near future, however, extensive investigations are still required to better understand their protection mechanisms.

A topical formulation containing quercetin-loaded microcapsules protects against oxidative and inflammatory skin alterations triggered by UVB irradiation: enhancement of activity by microencapsulation

Ultraviolet B (UVB) irradiation causes free radical production, increase inflammation and oxidative stress, thus, supporting the use of antioxidants by topical administration as therapeutic approaches. Quercetin (QC) is a flavonoid with antioxidant activity, however, high liposolubility makes it difficult to remain in the viable skin layer. Thus, this study evaluated whether microencapsulation of QC would enhance its activity in comparison with the same dose of free QC (non-active dose) and unloaded-microcapsules added in formulation for topical administration in a mouse model of UVB irradiation targeting the skin. Topical formulation containing Quercetin-loaded microcapsules (TFcQCMC) presents physico-chemical (colour, consistence, phase separation and pH) and functional antioxidant stability at 4 °C, room temperature and 40 °C for 6 months. TFcQCMC inhibited the UVB-triggered depletion of antioxidants observed by GSH (reduced glutathione), ability to reduce iron, ability to scavenge 2,2'-azinobis radical and catalase activity. TFcQCMC also inhibited markers of oxidation (lipid hydroperoxides and superoxide anion production). Concerning inflammation, TFcQCMC reduced the production of inflammatory cytokines, matrix metalloproteinase-9 activity, skin edoema, collagen fibre damage, myeloperoxidase activity/neutrophil recruitment, mast cell and sunburn cell counts. The pharmacological activity of TFcQCMC was not shared by the same pharmaceutical form containing the same dose of free QC or unloaded control microcapsules.

FLASH Proton Pencil Beam Scanning Irradiation Minimizes Radiation-Induced Leg Contracture and Skin Toxicity in Mice

Simple Summary

Dose and efficacy of radiation therapy are limited by the toxicity to normal tissue adjacent to the treated tumor region. Recently, ultra-high dose rate radiotherapy (FLASH radiotherapy) has shown beneficial reduction of normal tissue damage while preserving similar tumor efficacy with electron, photon and scattered proton beam irradiation in preclinical models. Proton therapy is increasingly delivered by pencil beam scanning (PBS) technology, and we therefore set out to test PBS FLASH radiotherapy on normal tissue toxicity and tumor control in vivo in mouse using a clinical proton delivery system. This validation of the FLASH normal tissue-sparing hypothesis with a clinical delivery system provides supporting data for PBS FLASH radiotherapy and its potential role in improving radiotherapy outcomes.

Abstract

Ultra-high dose rate radiation has been reported to produce a more favorable toxicity and tumor control profile compared to conventional dose rates that are used for patient treatment. So far, the so-called FLASH effect has been validated for electron, photon and scattered proton beam, but not yet for proton pencil beam scanning (PBS). Because PBS is the state-of-the-art delivery modality for proton therapy and constitutes a wide and growing installation base, we determined the benefit of FLASH PBS on skin and soft tissue toxicity. Using a pencil beam scanning nozzle and the plateau region of a 250 MeV proton beam, a uniform physical dose of 35 Gy (toxicity study) or 15 Gy (tumor control study) was delivered to the right hind leg of mice at various dose rates: Sham, Conventional (Conv, 1 Gy/s), Flash60 (57 Gy/s) and Flash115 (115 Gy/s). Acute radiation effects were quantified by measurements of plasma and skin levels of TGF-β1 and skin toxicity scoring. Delayed irradiation response was defined by hind leg contracture as a surrogate of irradiation-induced skin and soft tissue toxicity and by plasma levels of 13 different cytokines (CXCL1, CXCL10, Eotaxin, IL1-beta, IL-6, MCP-1, Mip1alpha, TNF-alpha, TNF-beta, VEGF, G-CSF, GM-CSF and TGF- β1). Plasma and skin levels of TGF-β1, skin toxicity and leg contracture were all significantly decreased in FLASH compared to Conv groups of mice. FLASH and Conv PBS had similar efficacy with regards to growth control of MOC1 and MOC2 head and neck cancer cells transplanted into syngeneic, immunocompetent mice. These results demonstrate consistent delivery of FLASH PBS radiation from 1 to 115 Gy/s in a clinical gantry. Radiation response following delivery of 35 Gy indicates potential benefits of FLASH versus conventional PBS that are related to skin and soft tissue toxicity.

Cutaneous Radiation Injuries: Models, Assessment and Treatments

Many cases of human exposures to high-dose radiation have been documented, including individuals exposed during the detonation of atomic bombs in Hiroshima and Nagasaki, nuclear power plant disasters (e.g., Chernobyl), as well as industrial and medical accidents. For many of these exposures, injuries to the skin have been present and have played a significant role in the progression of the injuries and survivability from the radiation exposure. There are also instances of radiation-induced skin complications in routine clinical radiotherapy and radiation diagnostic imaging procedures. In response to the threat of a radiological or nuclear mass casualty incident, the U.S. Department of Health and Human Services tasked the National Institute of Allergy and Infectious Diseases (NIAID) with identifying and funding early- to mid-stage medical countermeasure (MCM) development to treat radiation-induced injuries, including those to the skin. To appropriately assess the severity of radiation-induced skin injuries and determine efficacy of different approaches to mitigate/treat them, it is necessary to develop animal models that appropriately simulate what is seen in humans who have been exposed. In addition, it is important to understand the techniques that are used in other clinical indications (e.g., thermal burns, diabetic ulcers, etc.) to accurately assess the extent of skin injury and progression of healing. For these reasons, the NIAID partnered with two other U.S. Government funding and regulatory agencies, the Biomedical Advanced Research and Development Authority (BARDA) and the Food and Drug Administration (FDA), to identify state-of-the-art methods in assessment of skin injuries, explore animal models to better understand radiation-induced cutaneous damage and investigate treatment approaches. A two-day workshop was convened in May 2019 highlighting talks from 28 subject matter experts across five scientific sessions. This report provides an overview of information that was presented and the subsequent guided discussions.

Radiation-induced skin injury: pathogenesis, treatment, and management

Radiation-induced skin injury (RSI) refers to a frequently occurring complication of radiation therapy. Nearly 90% of patients having received radiation therapy underwent moderate-to-severe skin reactions, severely reducing patients' quality of life and adversely affecting their disease treatment. No gold standard has been formulated for RSIs. In the present study, the mechanism of RSI and topical medications was discussed. Besides, this study can be referenced for clinicians to treat RSIs to guide subsequent clinical medicine.

Quercetin reduces tendon adhesion in rat through suppression of oxidative stress

Background

Tendon adhesion is one of the most common clinical problems, which poses a considerable challenge to orthopedics doctors. Quercetin (QUE) as a popular drug at present, it has various biological functions, including anti-inflammatory, anti-ischemic, anti-peroxidation, and antioxidant. The purpose of this study was to investigate the effect of quercetin on tendon adhesion and whether quercetin can inhibit oxidative stress.

Method

Thirty-six rats were randomly divided into three groups, including control group, low QUE (50 mg/kg/day) group, and high QUE (100 mg/kg/day) group. After 1 week, the levels of SOD, MDA and GPx were measured. The degree of tendon adhesion was assessed by macroscopic evaluation and histological evaluation. After 4 weeks. Besides, the pharmacological toxicity of quercetin to main organs were evaluated by histological analysis.

Results

The extent of superoxide dismutase (SOD) and glutathione peroxidase (GPx) of tendon tissue in high QUE group was significantly higher than those of low QUE group and control group. And the extent of malondialdehyde (MDA) of tendon tissue in high QUE group was significantly lower than that of low QUE group and control group. By macroscopic evaluation and histological analysis, the extent of tendon adhesion in high QUE group was lower than low QUE group and control group. However, there were no significant changes of the major organs through histological analysis.

Conclusions

Quercetin may be a good and safe strategy in preventing tendon adhesion. But further clinical research is needed before its recommendation in the prevention and treatment of tendon adhesion.

Protective Effect of Low-Molecular-Weight Fucoidan on Radiation-Induced Fibrosis Through TGF-β1/Smad Pathway-Mediated Inhibition of Collagen I Accumulation

Radiation-induced fibrosis (RIF) occurs after radiation therapy in normal tissues due to excessive production and deposition of extracellular matrix proteins and collagen, possibly resulting in organ function impairment. This study investigates the effects of low-molecular-weight fucoidan (LMF) on irradiated NIH3T3 cells. Specifically, we quantified cellular metabolic activity, fibrosis-related mRNA expression, transforming growth factor beta-1 (TGF-β1), and collagen-1 protein expression, and fibroblast contractility in response to LMF. LMF pre + post-treatment could more effectively increase cellular metabolic activity compared with LMF post-treatment. LMF pre + post-treatment inhibited TGF-β1 expression, which mediates negative activation of phosphorylated Smad3 (pSmad3) and Smad4 complex formation and suppresses downstream collagen I accumulation. In addition, LMF pre + post-treatment significantly reduced actin-stress fibers in irradiated NIH3T3 cells. LMF, a natural substance obtained from brown seaweed, may be a candidate agent for preventing or inhibiting RIF.

Genome-Wide Analysis Reveals Zinc Transporter ZIP9 Regulated by DNA Methylation Promotes Radiation-Induced Skin Fibrosis via the TGF-β Signaling Pathway

Radiation-induced skin fibrosis is a detrimental and chronic disorder that occurs after radiation exposure. DNA methylation has been characterized as an important regulatory mechanism of multiple pathological processes. In this study, we compared the genome-wide DNA methylation status in radiation-induced fibrotic skin and adjacent normal tissues of rats by methylated DNA immunoprecipitation sequencing. Radiation-induced fibrotic skin showed differentially methylated regions associated with 3,650 protein-coding genes, 72 microRNAs, 5,836 long noncoding RNAs and 3 piwi-interacting RNAs. By integrating the mRNA and methylation profiles, the zinc transporter SLC39A9/ZIP9 was investigated in greater detail. The protein level of ZIP9 was increased in irradiated skin tissues of humans, monkeys, and rats, especially in radiogenic fibrotic skin tissues. Radiation induced the demethylation of a CpG dinucleotide in exon 1 of ZIP9 that resulted in recruitment of the transcriptional factor Sp1 and increased ZIP9 expression. Overexpression of ZIP9 resulted in activation of the profibrotic transforming growth factor-β signaling pathway through protein kinase B in human fibroblasts. In addition, radiation-induced skin fibrosis was associated with increased zinc accumulation. The zinc chelator N,N,N',N'-tetrakis(2-pyridylmethyl)-1,2-ethylenediamine abrogated ZIP9-induced activation of the transforming growth factor-β signaling pathway and attenuated radiation-induced skin fibrosis in a rat model. In summary, our findings illustrate epigenetic regulation of ZIP9 and its critical role in promoting radiation-induced skin fibrosis.

Intercellular communications-redox interactions in radiation toxicity; potential targets for radiation mitigation

Nowadays, using ionizing radiation (IR) is necessary for clinical, agricultural, nuclear energy or industrial applications. Accidental exposure to IR after a radiation terror or disaster poses a threat to human. In contrast to the old dogma of radiation toxicity, several experiments during the last two recent decades have revealed that intercellular signaling and communications play a key role in this procedure. Elevated level of cytokines and other intercellular signals increase oxidative damage and inflammatory responses via reduction/oxidation interactions (redox system). Intercellular signals induce production of free radicals and inflammatory mediators by some intermediate enzymes such as cyclooxygenase-2 (COX-2), nitric oxide synthase (NOS), NADPH oxidase, and also via triggering mitochondrial ROS. Furthermore, these signals facilitate cell to cell contact and increasing cell toxicity via cohort effect. Nitric oxide is a free radical with ability to act as an intercellular signal that induce DNA damage and changes in some signaling pathways in irradiated as well as non-irradiated adjacent cells. Targeting of these mediators by some anti-inflammatory agents or via antioxidants such as mitochondrial ROS scavengers opens a window to mitigate radiation toxicity after an accidental exposure. Experiments which have been done so far suggests that some cytokines such as IL-1β, TNF-α, TGF-β, IL-4 and IL-13 are some interesting targets that depend on irradiated organs and may help mitigate radiation toxicity. Moreover, animal experiments in recent years indicated that targeting of toll like receptors (TLRs) may be more useful for radioprotection and mitigation. In this review, we aimed to describe the role of intercellular interactions in oxidative injury, inflammation, cell death and killing effects of IR. Moreover, we described evidence on potential mitigation of radiation injury via targeting of these mediators.

Reactive Oxygen Species Drive Epigenetic Changes in Radiation-Induced Fibrosis

Radiation-induced fibrosis (RIF) develops months to years after initial radiation exposure. RIF occurs when normal fibroblasts differentiate into myofibroblasts and lay down aberrant amounts of extracellular matrix proteins. One of the main drivers for developing RIF is reactive oxygen species (ROS) generated immediately after radiation exposure. Generation of ROS is known to induce epigenetic changes and cause differentiation of fibroblasts to myofibroblasts. Several antioxidant compounds have been shown to prevent radiation-induced epigenetic changes and the development of RIF. Therefore, reviewing the ROS-linked epigenetic changes in irradiated fibroblast cells is essential to understand the development and prevention of RIF.

Novel pharmacotherapy for burn wounds: what are the advancements

INTRODUCTION

The prognosis for severe burns has improved significantly over the past 50 years. Meanwhile, burns have become an affliction mainly affecting the less well-developed regions of the world. Early excision and skin grafting has led to major improvements in therapeutic outcomes.

AREAS COVERED

The purpose of this article is to survey the use of pharmacotherapy to treat different pathophysiological complications of burn injury. The author, herein, discusses the use of drug treatments for a number of systemic metabolic disturbances including hyperglycemia, elevated catabolism, and gluconeogenesis.

EXPERT OPINION

Advancements in personalized and molecular medicine will make an impact on burn therapy. Similarities between severe burns and other critically ill patients will lead to cross-fertilization between different medical specialties. Furthermore, advances in stem cells and tissue regeneration will lead to improved healing and less lifelong disability. Indeed, research in new drug therapy for burns is actively progressing for many different complications.

Agro-Industrial By-Products and Their Bioactive Compounds—An Ally against Oxidative Stress and Skin Aging

The increased consumer awareness towards hazards related with sun exposure has given a boost in the cosmetics industry and particularly the sun care market. Human skin is continually being threatened by the UV irradiation present in sunlight and acute UV exposure leads to skin photoaging. Cosmetic and/or dermatological applications include several bioactive compounds that contribute to the regulation of epidermal homeostasis by providing protection against solar radiation and improving the antioxidant activity of epidermis. Plant extracts are sources of active ingredients with intense therapeutic properties, and the topical application or oral intake of these compounds could ameliorate skin condition. Nowadays, there is a growing demand for the application of the bioactive agents contained in agro-industrial byproducts in sun care products, since many of them have shown promising properties as skin photoprotectants. However, well-conducted clinical studies are required to prove their safety and efficacy before they could be regularly used. Environmentally friendly extraction and sustainable techniques are therefore under examination for recovering such compounds from agro-industrial byproducts and converting them into innovative high-value natural ingredients used in cosmetic formulations.

Preclinical quantitative in-vivo assessment of skin tissue vascularity in radiation-induced fibrosis with optical coherence tomography

Radiation therapy (RT) is widely and effectively used for cancer treatment but can also cause deleterious side effects, such as a late-toxicity complication called radiation-induced fibrosis (RIF). Accurate diagnosis of RIF requires analysis of histological sections to assess extracellular matrix infiltration. This is invasive, prone to sampling limitations, and thus rarely used; instead, current practice relies on subjective clinical surrogates, including visual observation, palpation, and patient symptomatology questionnaires. This preclinical study demonstrates that functional optical coherence tomography (OCT) is a useful tool for objective noninvasive in-vivo assessment and quantification of fibrosis-associated microvascular changes in tissue. Data were collected from murine hind limbs 6 months after 40-Gy single-dose irradiation and compared with nonirradiated contralateral tissues of the same animals. OCT-derived vascular density and average vessel diameter metrics were compared to quantitative vascular analysis of stained histological slides. Results indicate that RIF manifests significant microvascular changes at this time point posttreatment. Abnormal microvascular changes visualized by OCT in this preclinical setting suggest the potential of this label-free high-resolution noninvasive functional imaging methodology for RIF diagnosis and assessment in the context of clinical RT.

Study of the Potential Radiomitigator Effect of Quercetin on Human Lymphocytes

Several substances of synthetic and natural origin have been studied to determine their ability to protect the body from damage caused by ionizing radiation. Among these substances, quercetin has been shown to be a naturally occurring molecule with high radioprotective and radiomitigator potential due to its antioxidant properties. The objective of this work was to ascertain the potential radiomitigator effect of quercetin on chromosome aberration yield in lymphocytes of in vitro-irradiated human peripheral blood. At first, the DPPH (2,2-diphenyl-1-picryl-hydrazyl) radical capture test was performed to determine the antioxidant activity of quercetin and to select the concentrations to be tested. The blood was irradiated at doses of 2.5, 3.5, and 4.5 Gy and lymphocytes were cultured with quercetin at preselected concentrations of 37.5 and 75 μM. Then, the slides were prepared for scoring unstable chromosome aberrations (dicentrics, rings, and fragments). The results showed that the lymphocytes irradiated and later exposed to quercetin presented a lower frequency of chromosomal alterations compared to the control sample which was irradiated and not exposed to quercetin. The results suggest a potential radiomitigator effect of the flavonoid quercetin on human lymphocytes exposed, in vitro, to ionizing radiation. This effect may be related to decrease in the release of cytokines (INF-γ, PGE2, IL-1β, IL6, IL-8) involved in the proinflammatory processes as well as downregulation of NF-kB and reduction of expression TGF-β.

Prevention from radiation damage by natural products

BACKGROUND

Radiotherapy is a mainstay of cancer treatment since decades. Ionizing radiation (IR) is used for destruction of cancer cells and shrinkage of tumors. However, the increase of radioresistance in cancer cells and radiation toxicity to normal tissues are severe concerns. The exposure to radiation generates intracellular reactive oxygen species (ROS), which leads to DNA damage by lipid peroxidation, removal of thiol groups from cellular and membrane proteins, strand breaks and base alterations.

HYPOTHESIS

Plants have to deal with radiation-induced damage (UV-light of sun, other natural radiation sources). Therefore, it is worth speculating that radioprotective mechanisms have evolved during evolution of life. We hypothesize that natural products from plants may also protect from radiation damage caused as adverse side effects of cancer radiotherapy.

METHODS

The basis of this systematic review, we searched the relevant literature in the PubMed database.

RESULTS

Flavonoids, such as genistein, epigallocatechin-3-gallate, epicatechin, apigenin and silibinin mainly act as antioxidant, free radical scavenging and anti-inflammatory compounds, thus, providing cytoprotection in addition to downregulation of several pro-inflammatory cytokines. Comparable effects have been found in phenylpropanoids, especially caffeic acid phenylethylester, curcumin, thymol and zingerone. Besides, resveratrol and quercetin are the most important cytoprotective polyphenols. Their radioprotective effects are mediated by a wide range of mechanisms mainly leading to direct or indirect reduction of cellular stress. Ascorbic acid is broadly used as antioxidant, but it has also shown activity in reducing cellular damage after irradiation mainly due to its antioxidant capabilities. The metal ion chelator, gallic acid, represents another natural product attenuating cellular damage caused by radiation.

CONCLUSIONS

Some secondary metabolites from plants reveal radioprotective features against cellular damage caused by irradiation. These results warrant further analysis to develop phytochemicals as radioprotectors for clinical use.

The Role of FABP5 in Radiation-Induced Human Skin Fibrosis

Radiation-induced skin fibrosis is a detrimental and chronic disorder that occurs after radiation exposure. The molecular changes underlying the pathogenesis of radiation-induced fibrosis of human skin have not been extensively reported. Technical advances in proteomics have enabled exploration of the biomarkers and molecular pathogenesis of radiation-induced skin fibrosis, with the potential to broaden our understanding of this disease. In this study, we compared protein expression in radiation-induced fibrotic human skin and adjacent normal tissues using iTRAQ-based proteomics technology. We identified 186 preferentially expressed proteins (53 upregulated and 133 downregulated) between radiogenic fibrotic and normal skin tissues. The differentially expressed proteins included keratins (KRT5, KRT6A, KRT16 and KRT17), caspase-14, fatty acid-binding protein 5 (FABP5), SLC2A14 and resistin. Through bioinformatic analysis of the proximal promoters, common motifs and corresponding transcriptional factors were identified that associate with the dysregulated proteins, including PAX5, TBX1, CLOCK and AP2D. In particular, FABP5 (2.15-fold increase in fibrotic skin tissues), a transporter of hydrophobic fatty acids, was investigated in greater detail. Immunohistochemistry confirmed that the protein level of FABP5 was increased in fibrotic human skin tissues, especially in the epidermis. Overexpression of FABP5 resulted in nuclear translocation of SMAD2 and significant activation of the profibrotic TGF-β signaling pathway in human fibroblast WS1 cells. Moreover, exogenous FABP5 (FABP5-EGFP) could be incorporated by skin cells and intensify TGF-β signaling, indicating a communication between the microenvironment and skin fibrosis. Taken together, our findings illustrate the molecular changes during radiation-induced human skin fibrosis and the critical role of FABP5 in activating the TGF-β signaling pathway.

The impact of quercetin on wound healing relates to changes in αV and β1 integrin expression

Overly fibrotic wound healing can lead to excess scar formation, causing functional impairment and undesirable cosmetic results. However, there are few successful treatments available to prevent or remediate scars. This study sought to explore the molecular mechanisms by which quercetin, a naturally-occurring antifibrotic agent, diminishes scar formation. Using both mice and fibroblast cells, we examined quercetin's impact on fibrosis and the wound healing rate, and potential molecular mechanisms underlying the quercetin-mediated reduction of fibrosis. While cultured fibroblasts demonstrated normal growth in response to quercetin, quercetin increased surface αV integrin and decreased β1 integrin. These changes in surface integrin expression may impact factors that contribute to fibrosis including cell migration, proliferation, and extracellular matrix production. In both quercetin-treated and control mice, wounds healed in about 14 days. Masson's trichrome stain revealed diminished fibrosis at the wound site in quercetin-treated animals despite the normal healing rate, indicating the potential for better cosmetic results without delaying healing. An in vitro scratch wound model using cells plated on an artificial extracellular matrix demonstrated delayed closure following quercetin treatment. The extracellular matrix also ameliorated quercetin's effect on αV integrin. Thus, αV integrin recruitment in response to quercetin treatment may promote the quercetin-mediated decrease extracellular matrix because cells require less extracellular matrix to migrate into a wound. With added extracellular matrix, β1 integrin remained diminished in response to quercetin, indicating that quercetin's effect on β1 integrin expression is independent of extracellular matrix -mediated signaling and is likely driven by inhibition of the intracellular mechanisms driving β1 expression. These findings suggest that quercetin could alter the cells' interactions with the extracellular matrix through the regulation of integrin expression to promote a decrease in fibrosis. Furthermore, this work demonstrates that this naturally occurring and commercially available supplement could be used to improve wound healing by impacting integrin expression, leading to a lower extracellular matrix requirement to achieve healing. Impact statement Scar formation during wound healing can be problematic for patients but there are limited therapies available to treat or prevent excess fibrosis at wound sites. This work examines the impact of quercetin, a flavonoid that decreases fibrosis, on wound healing, and relates quercetin's effects to changes in integrin expression on the surface of fibroblast cells. To our knowledge, this is the first report that quercetin alters integrin expression or that this impact may be part of the mechanism by which quercetin prevents fibrosis. This work demonstrates that quercetin can be used to modulate integrin expression and that this effect may in turn reduce fibrosis during wound healing. Furthermore, this paper identifies the modulation of integrin expression as a possible therapeutic target in preventing scars. This information could be used to improve therapeutics to aid in the cosmetic and functional results following wound healing.

Effect of cancer-associated fibroblasts on radiosensitivity of cancer cells

Solid tumors are composed of tumor epithelial cells and the stroma, which are seemingly separate but actually related through cell-cell and cell-matrix interactions. These interactions can promote tumor evolution. Cancer-associated fibroblasts (CAFs) are the most abundant non-neoplastic cells in the stroma and also among the most important cell types interacting with cancer cells. Particularly, cancer cells promote the formation and maintenance of CAFs by secreting various cytokines. The activated CAFs then synthesize a series of growth factors to promote tumor cell growth, invasion and metastasis. More importantly, the presence of CAFs also interferes with therapeutic efficacy, bringing severe challenges to radiotherapy. This review summarizes the effect of CAFs on the radiosensitivity of tumor cells and underscores the need for further studies on CAFs in order to improve the efficacy of antitumor therapy.

Chronic radiation-induced dermatitis: challenges and solutions

Chronic radiation dermatitis is a late side effect of skin irradiation, which may deteriorate patients’ quality of life. There is a lack of precise data about its incidence; however, several risk factors may predispose to the development of this condition. It includes radiotherapy dose, fractionation, technique, concurrent systemic therapy, comorbidities, and personal and genetic factors. Chronic radiation dermatitis is mostly caused by the imbalance of proinflammatory and profibrotic cytokines. Clinical manifestation includes changes in skin appearance, wounds, ulcerations, necrosis, fibrosis, and secondary cancers. The most severe complication of irradiation is extensive radiation-induced fibrosis (RIF). RIF can manifest in many ways, such as skin induration and retraction, lymphedema or restriction of joint motion. Diagnosis of chronic radiation dermatitis is usually made by clinical examination. In case of unclear clinical manifestation, a biopsy and histopathological examination are recommended to exclude secondary malignancy. The most effective prophylaxis of chronic radiation dermatitis is the use of proper radiation therapy techniques to avoid unnecessary irradiation of healthy skin. Treatment of chronic radiation dermatitis is demanding. The majority of the interventions are based only on clinical practice. Telangiectasia may be treated with pulse dye laser therapy. Chronic postirradiation wounds need special dressings. In case of necrosis or severe ulceration, surgical intervention may be considered. Management of RIF should be complex. Available methods are rehabilitative care, pharmacotherapy, hyperbaric oxygen therapy, and laser therapy. Future challenges include the assessment of late skin toxicity in modern irradiation techniques. Special attention should be paid on genomics and radiomics that allow scientists and clinicians to select patients who are at risk of the development of chronic radiation dermatitis. Novel treatment methods and clinical trials are strongly needed to provide more efficacious therapies.

Chitosan nanoparticles plus quercetin suppress the oxidative stress, modulate DNA fragmentation and gene expression in the kidney of rats fed ochratoxin A-contaminated diet

This study aimed to evaluate the protective role of chitosan nanoparticles (COS-NPs) singly or plus quercetin (Q) against OTA-induced oxidative stress and renal genotoxicity. Twelve groups of male Sprague-Dawley rats were treated orally for 3 weeks included the control group, animals fed OTA-contaminated diet (3 mg/kg diet); COS-NPs-treated groups at low (140 mg/kg b.w.) or high (280 mg/kg b.w.) dose, Q-treated group (50 mg/kg b.w.), Q plus low or high dose of COS-NPs-treated groups and OTA plus Q and/or COS-NPs at the two tested doses-treated groups. The results indicated that COS-NPs were roughly rod in shape with average particle size of 200 nm and zeta potential 31.4 ± 2.8 mV. Animals fed OTA-contaminated diet showed significant changes in serum biochemical parameters, increase kidney MDA and DNA fragmentation and decreased GPx and SOD gene expression accompanied with severe histological changes. Q and/or COS-NPs at the two tested doses induced significant improvements in all tested parameters and succeeded to overcome these effects especially in the animals treated with Q plus the high dose of COS-NPs. It could be concluded that COS-NPs are promise candidate to enhance the antioxidant effect of Q and protect against the nephrotoxicity of OTA in high endemic areas.

Quercetin as an Emerging Anti-Melanoma Agent: A Four-Focus Area Therapeutic Development Strategy

Replacing current refractory treatments for melanoma with new prevention and therapeutic approaches is crucial in order to successfully treat this aggressive cancer form. Melanoma develops from neural crest cells, which express tyrosinase – a key enzyme in the pigmentation pathway. The tyrosinase enzyme is highly active in melanoma cells and metabolizes polyphenolic compounds; tyrosinase expression thus makes feasible a target for polyphenol-based therapies. For example, quercetin (3,3′,4′,5,7-pentahydroxyflavone) is a highly ubiquitous and well-classified dietary polyphenol found in various fruits, vegetables, and other plant products including onions, broccoli, kale, oranges, blueberries, apples, and tea. Quercetin has demonstrated antiproliferative and proapoptotic activity in various cancer cell types. Quercetin is readily metabolized by tyrosinase into various compounds that promote anticancer activity; additionally, given that tyrosinase expression increases during tumorigenesis, and its activity is associated with pigmentation changes in both early- and late-stage melanocytic lesions, it suggests that quercetin can be used to target melanoma. In this review, we explore the potential of quercetin as an anti-melanoma agent utilizing and extrapolating on evidence from previous in vitro studies in various human malignant cell lines and propose a “four-focus area strategy” to develop quercetin as a targeted anti-melanoma compound for use as either a preventative or therapeutic agent. The four areas of focus include utilizing quercetin to (i) modulate cellular bioreduction potential and associated signaling cascades, (ii) affect transcription of relevant genes, (iii) regulate epigenetic processes, and (iv) develop effective combination therapies and delivery modalities/protocols. In general, quercetin could be used to exploit tyrosinase activity to prevent, and/or treat, melanoma with minimal additional side effects.

A chemical screen for medulloblastoma identifies quercetin as a putative radiosensitizer

Treatment of medulloblastoma in children fails in approximately 30% of patients, and is often accompanied by severe late sequelae. Therefore, more effective drugs are needed that spare normal tissue and diminish long-term side effects. Since radiotherapy plays a pivotal role in the treatment of medulloblastoma, we set out to identify novel drugs that could potentiate the effect of ionizing radiation.Thereto, a small molecule library, consisting of 960 chemical compounds, was screened for its ability to sensitize towards irradiation. This small molecule screen identified the flavonoid quercetin as a novel radiosensitizer for the medulloblastoma cell lines DAOY, D283-med, and, to a lesser extent, D458-med at low micromolar concentrations and irradiation doses used in fractionated radiation schemes. Quercetin did not affect the proliferation of neural precursor cells or normal human fibroblasts. Importantly, in vivo experiments confirmed the radiosensitizing properties of quercetin. Administration of this flavonoid at the time of irradiation significantly prolonged survival in orthotopically xenografted mice. Together, these findings indicate that quercetin is a potent radiosensitizer for medulloblastoma cells that may be a promising lead for the treatment of medulloblastoma in patients.

Acute and Chronic Cutaneous Reactions to Ionizing Radiation Therapy

Ionizing radiation is an important treatment modality for a variety of malignant conditions. However, development of radiation-induced skin changes is a significant adverse effect of radiation therapy (RT). Cutaneous repercussions of RT vary considerably in severity, course, and prognosis. When they do occur, cutaneous changes to RT are commonly graded as acute, consequential-late, or chronic. Acute reactions can have severe sequelae that impact quality of life as well as cancer treatment. Thus, dermatologists should be informed about these adverse reactions, know how to assess their severity and be able to determine course of management. The majority of measures currently available to prevent these acute reactions are proper skin hygiene and topical steroids, which limit the severity and decrease symptoms. Once acute cutaneous reactions develop, they are treated according to their severity. Treatments are similar to those used in prevention, but incorporate wound care management that maintains a moist environment to hasten recovery. Chronic changes are a unique subset of adverse reactions to RT that may develop months to years following treatment. Chronic radiation dermatitis is often permanent, progressive, and potentially irreversible with substantial impact on quality of life. Here, we also review the etiology, clinical manifestations, pathogenesis, prevention, and management of late-stage cutaneous reactions to radiotherapy, including chronic radiation dermatitis and radiation-induced fibrosis.

Quercetin Inhibits Fibroblast Activation and Kidney Fibrosis Involving the Suppression of Mammalian Target of Rapamycin and β-catenin Signaling

Quercetin, a flavonoid found in a wide variety of plants and presented in human diet, displays promising potential in preventing kidney fibroblast activation. However, whether quercetin can ameliorate kidney fibrosis in mice with obstructive nephropathy and the underlying mechanisms remain to be further elucidated. In this study, we found that administration of quercetin could largely ameliorate kidney interstitial fibrosis and macrophage accumulation in the kidneys with obstructive nephropathy. MTORC1, mTORC2, β-catenin as well as Smad signaling were activated in the obstructive kidneys, whereas quercetin could markedly reduce their abundance except Smad3 phosphorylation. In cultured NRK-49F cells, quercetin could inhibit α-SMA and fibronectin (FN) expression induced by TGFβ1 treatment. MTORC1, mTORC2, β-catenin and Smad signaling pathways were stimulated by TGFβ1 at a time dependent manner. Similar to those findings in the obstructive kidneys, mTORC1, mTORC2 and β-catenin, but not Smad signaling pathways were remarkably blocked by quercetin treatment. Together, these results suggest that quercetin inhibits fibroblast activation and kidney fibrosis involving a combined inhibition of mTOR and β-catenin signaling transduction, which may act as a therapeutic candidate for patients with chronic kidney diseases.

Proteomic Profiling of Radiation-Induced Skin Fibrosis in Rats: Targeting the Ubiquitin-Proteasome System

PURPOSE

To investigate the molecular changes underlying the pathogenesis of radiation-induced skin fibrosis.

METHODS AND MATERIALS

Rat skin was irradiated to 30 or 45 Gy with an electron beam. Protein expression in fibrotic rat skin and adjacent normal tissues was quantified by label-free protein quantitation. Human skin cells HaCaT and WS-1 were treated by x-ray irradiation, and the proteasome activity was determined with a fluorescent probe. The effect of proteasome inhibitors on Transforming growth factor Beta (TGF-B) signaling was measured by Western blot and immunofluorescence. The efficacy of bortezomib in wound healing of rat skin was assessed by the skin injury scale.

RESULTS

We found that irradiation induced epidermal and dermal hyperplasia in rat and human skin. One hundred ninety-six preferentially expressed and 80 unique proteins in the irradiated fibrotic skin were identified. Through bioinformatic analysis, the ubiquitin-proteasome pathway showed a significant fold change and was investigated in greater detail. In vitro experiments demonstrated that irradiation resulted in a decline in the activity of the proteasome in human skin cells. The proteasome inhibitor bortezomib suppressed profibrotic TGF-β downstream signaling but not TGF-β secretion stimulated by irradiation in HaCaT and WS-1 cells. Moreover, bortezomib ameliorated radiation-induced skin injury and attenuated epidermal hyperplasia.

CONCLUSION

Our findings illustrate the molecular changes during radiation-induced skin fibrosis and suggest that targeting the ubiquitin-proteasome system would be an effective countermeasure.

Chitosan nanoparticles and quercetin modulate gene expression and prevent the genotoxicity of aflatoxin B1 in rat liver

The aims of the current study were to prepare chitosan nanoparticles (CNPs) and to evaluate its protective role alone or in combination with quercetin (Q) against AFB₁-induce cytotoxicity in rats. Male Sprague-Dawley rats were divided into 12 groups and treated orally for 4 weeks as follow: the control group, the group treated with AFB₁ (80 μg/kg b.w.) in corn oil, the groups treated with low (140 mg/kg b.w.) or high (280 mg/kg b.w.) dose of CNPs, the group treated with Q (50 mg/kg b.w.), the groups treated with Q plus the low or the high dose of CNPs and the groups treated with AFB₁ plus Q and/or CNPs at the two tested doses. The results also revealed that administration of AFB₁ resulted in a significant increase in serum cytokines, Procollagen III, Nitric Oxide, lipid peroxidation and DNA fragmentation accompanied with a significant decrease in GPx I and Cu–Zn SOD-mRNA gene expression. Q and/or CNPs at the two tested doses overcome these effects especially in the group treated with the high dose of CNPs plus Q. It could be concluded that CNPs is a promise candidate as drug delivery enhances the protective effect of Q against the cytogenetic effects of AFB₁ in high endemic areas.