Biomarkers Associated with Radiation-Induced Lung Injury in Cancer Patients

Radiotherapy (RT) is a common and effective non-surgical treatment for thoracic solid tumors, and radiation-induced lung injury (RILI) is the most common side effect of radiotherapy. Even if RT is effective in the treatment of cancer patients, severe radiation pneumonitis (RP) or pulmonary fibrosis (PF) can reduce the quality of life of patients and may even lead to serious consequences of death. Therefore, how to overcome the problem of accurate prediction and early diagnosis of RT for pulmonary toxicity is very important. This review summarizes the related factors of RILI and the related biomarkers for early prediction of RILI.

Correlation between miR-564, TGF-β1, and radiation-induced lung injury

Objective Our study aimed to analyze the expression of miR-564 and TGF-β1 in cancer tissues and the serum of patients with radiation-induced lung injury,and to investigate the relationship between them and radiation-induced lung injury.Methods In situ hybridization and real-time fluorescence quantitative method were used to detect the expression of miR-564.Additionally,immunohistochemistry and enzyme-linked immunosorbent assay(ELISA)were performed to detect the expression of TGF-β1.Results The overall incidence of acute radiation pneumonia was 55.9%(100/179).The incidence of≥grade 2 radioactive pneumonia was 24.0%(43/179)and that of grade 1 was 31.8%(57/179).The expression of miR-564 in grade≥2 was slightly higher than that in patients without or with grade 1,but there was no statistical difference(P=0.86).The serum level and ratio of miR-564 in patients with grade≥2 were significantly higher than those without or with grade 1(P=0.005,P=0.025,respectively).The expression of TGF-β1 in grade≥2 was significantly higher than that of patients without or with grade 1(P=0.017).The serum levels of TGF-β1 in grade≥2 were significantly higher than those in patients without or with grade 1(P=0.038).Although the ratio of TGF-β1 in radiation pneumonia of grade≥2 was significantly higher than that of without or with grade 1,there was no significant difference(P=0.24).Moreover,patients with higher expression of miR-564 and lower expression of TGF-β1 had better prognosis.Conclusion MiR-564 and TGF-β1 are predictors of radiation-induced lung injury.Monitoring its changing trend can improve the accuracy of predicting radiation-induced lung injury.The levels and ratio of serum miR-564 and TGF-β1 in patients with radiation-induced lung injury are related to the severity of radiationinduced lung injury.

Rabbit model of radiation-induced lung injury

Objective:To explore the feasibility of establishing an animal model of chronic radiationinduced lung injury.Methods:Twenty-eight New Zealand white rabbits were randomly divided into 3 groups(the right lung irradiation group,the whole lung irradiation group and the control group).Animal model of radiation-induced lung injury was established b) highdoes radiotherapy in the irradiation groups,then all rabbits underwent CT and pathological examinations at 1.2.4.8.12.16 weeks,respectively after radiation.Results:Within 4 weeks of irradiation,some rabbits in the right lung irradiation group and whole lung irradiation group died. CT and pathological examinations all showed acute radiation pneumonitis.At 8-12 weeks after irradiation,CT scanning showed ground glass samples signs,patchy shadows and fibrotic stripes. Pathological examination showed the fibrosis pulmonary alveolar wall thickened obviously. Conclusions:The clinical animal model of chronic radiation-induced lung injury which corresponds to practical conditions in clinic can be successfully established.

Prevention and treatment of radiation-induced lung injury by hydroxypiperquin phosphate: a clinical and experimental study

Objective: To evaluate the hydroxypiperquin phosphate (HPQP) as a modifier of radiation-induced injury in human and rat lungs. Methods: Sixty-five patients with lung cancer treated with conventional radiotherapy were divided into 2 groups randomly: Thirty cases were treated with HPQP and the others were in a control group. The changes of X - ray manifestation before, after and during taking drug were compared. An animal model of radiation-induced fibrosis of lungs was also established. Hydroxyproling (HP) content in lung tissue and the pathological changes in rat lungs were checked with microscope and electron microscope after 4 months and 6 months respectively. Results: The changes of lung X-ray manifestation in treatment group were much lighter than that in control group. The HP content and the change of pathology in the lungs of those rats with HPQP treatment were obviously less than that in control group. Conclusion: HPQP plays an important role in prevention and treatment of radiation-induced injury in lungs.

Expression of Angiotensin Ⅱ and Aldosterone in Radiation-induced Lung Injury

Objective Radiation-induced lung injury(RILI) is the most common,dose-limiting complication in thoracic malignancy radiotherapy.Considering its negative impact on patients and restrictions to efficacy,the mechanism of RILI was studied. Methods Wistar rats were locally irradiated with a single dose of 0,16,and 20 Gy to the right half of the lung to establish a lung injury model.Two and six months after irradiation,the right half of the rat lung tissue was removed,and the concentrations of TGF-β1,angiotensinⅡ,and aldosterone were determined via enzyme-linked immunosorbent assay. Results Statistical differences were observed in the expression levels of angiotensinⅡand aldosterone between the non-irradiation and irradiation groups.Moreover,the expression level of the angiotensinⅡ-aldosterone system increased with increasing doses,and the difference was still observed as time progressed. Conclusions AngiotensinⅡ-aldosterone system has an important pathophysiological function in the progression of RILI.

GSN antibody pretreatment aggravates radiation-induced lung injury in mice

Radiation-induced lung injury is one of the main dose limiting factors for thoracic radiation therapy.Gelsolin(GSN) is a widespread,multifunctional regulator of cellular structure and metabolism.In this work,the roles of GSN in radiation-induced lung injury in Balb/c mice were studied.The GSN levels in plasma reduced progressively in 72 hours after irradiation,and then increased gradually.GSN contents in the bronchoalveolar lavage(BAL) fluid increased after thoracic irradiation,whereas mRNA levels of GSN in the lung tissue decreased significantly within 24 hours after irradiation and then increased again.Mice were intravenously injected with 50 ug GSN antibody 0.5 hour before 20 Gy of thoracic irradiation.GSN antibody pretreatment increased lung inflammation,protein concentration in the BAL fluid and leukocytes infiltration in the irradiated mice.The activities of superoxidase dismutase(SOD) in the plasma and the BAL fluid in irradiated mice injected with GSN antibody were less than that of control groups,whereas the levels of malondialdehyde(MDA)increased.These results suggest that pretreatment of GSN antibody may aggravate radiation-induced pneumonitis.

An Appreciation for the Rabbit Ladderlike Modeling of Radiation-induced Lung Injury with High-energy X-Ray

Background：To evaluate the utility of rabbit ladderlike model of radiation-induced lung injury （RILI） for the future investigation of computed tomography perfusion.Methods：A total of 72 New Zealand rabbits were randomly divided into two groups：36 rabbits in the test group were administered 25 Gy of single fractionated radiation to the whole lung of unilateral lung;36 rabbits in the control group were sham-radiated.All rabbits were subsequently sacrificed at 1,6,12,24,48,72 h,and 1,2,4,8,1 6,24 weeks after radiation,and then six specimens were extracted from the upper,middle and lower fields of the bilateral lungs.The pathological changes in these specimens were observed with light and electron microscopy;the expression of tumor necrosis factor-α （TNF-a） and transforming growth factor-βl （TGF-β1） in local lung tissue was detected by immunohistochemistry.Results：（1） Radiation-induced lung injury occurred in all rabbits in the test group.（2） Expression of TNF-a and TGF-β1 at 1 h and 48 h after radiation,demonstrated a statistically significant difference between the test and control groups （each P 〈 0.05）.（3） Evaluation by light microscopy demonstrated statistically significant differences between the two groups in the following parameters （each P 〈 0.05）：thickness of alveolar wall,density of pulmonary interstitium area （1 h after radiation）,number offibroblasts and fibrocytes in interstitium （24 h after radiation）.The test group metrics also correlated well with the time ofpostradiation.（4） Evaluation by electron microscopy demonstrated statistically significant differences in the relative amounts of collagen fibers at various time points postradiation in the test group （P 〈 0.005）,with no significant differences in the control group （P 〉 0.05）.At greater than 48 h postradiation the relative amount of collagen fibers in the test groups significantly differ from the control groups （each P 〈 0.05）,correlating well with the time postradiation （r =0.99318）.Conclusions：A consistent and reliable rabbit model of RILI can be generated in gradient using 25 Gy of high-energy X-ray,which can simulate the development and evolution of RILI.

Treatment of radiation-induced brain injury with bisdemethoxycurcumin

Radiation therapy is considered the most effective non-surgical treatment for brain tumors.However,there are no available treatments for radiation-induced brain injury.Bisdemethoxycurcumin(BDMC)is a demethoxy derivative of curcumin that has anti-proliferative,anti-inflammatory,and anti-oxidant properties.To determine whether BDMC has the potential to treat radiation-induced brain injury,in this study,we established a rat model of radiation-induced brain injury by administe ring a single 30-Gy vertical dose of irradiation to the whole brain,followed by intraperitoneal injection of 500μL of a 100 mg/kg BDMC solution every day for 5 successive weeks.Our res ults showed that BDMC increased the body weight of rats with radiation-induced brain injury,improved lea rning and memory,attenuated brain edema,inhibited astrocyte activation,and reduced oxidative stress.These findings suggest that BDMC protects against radiationinduced brain injury.

TLD calibration and absorbed dose measurement in a radiation-induced liver injury model under a linear accelerator

The application of a thermoluminescent detector(TLD) for dose detection at the liver irradiation site in mice under linear accelerator precision radiotherapy and the use of a single high dose to irradiate the mouse liver to construct a biological model of a radiation-induced liver injury(RILD) in mice were to determine the feasibility of constructing a precision radiotherapy model in small animals under a linear accelerator. A 360° arc volumetric rotational intensity-modulated radiotherapy(VMAT) plan with a prescribed dose of 2 Gy was developed for the planned target volume(PTV) at the location of the TLD within solid water to compare the difference between the measured dose of TLD and the assessed parameters in the TPS system. The TLD was implanted in the livers of mice, and VMAT was planned based on TLD to compare the measured and prescribed doses. C57BL/6 J mice were randomly divided into control and 25-Gy radiation groups and were examined daily for changes in body weight. They were euthanized at 3 and 10 weeks after radiation, and the levels of liver serum enzymes such as alanine aminotransferase(ALT), aspartate aminotransferase(AST), and alkaline phosphatase(ALP) were measured to observe any pathological histological changes in the irradiated areas of the mouse liver. The measured values of solid underwater TLD were within ± 3% of the Dmean value of the evaluation parameter in the TPS system. The mice in the 25-Gy radiation group demonstrated pathological signs of radiation-induced liver injury at the site of liver irradiation. The deviation in the measured and prescribed doses of TLD in the mouse liver ranged from-1.5 to 6%;construction of an accurate model of RILD using the VMAT technique under a linear accelerator is feasible.

Mogroside IIE,an in vivo metabolite of sweet agent,alleviates acute lung injury via Pla2g2a-EGFR inhibition

In the face of increasingly serious environmental pollution,the health of human lung tissues is also facing serious threats.Mogroside IIE(M2E)is the main metabolite of sweetening agents mogrosides from the anti-tussive Chinese herbal Siraitia grosvenori.The study elucidated the anti-inflammatory action and molecular mechanism of M2E against acute lung injury(ALI).A lipopolysaccharide(LPS)-induced ALI model was established in mice and MH-S cells were employed to explore the protective mechanism of M2E through the western blotting,co-immunoprecipitation,and quantitative real time-PCR analysis.The results indicated that M2E alleviated LPS-induced lung injury through restraining the activation of secreted phospholipase A2 type IIA(Pla2g2a)-epidermal growth factor receptor(EGFR).The interaction of Pla2g2a and EGFR was identified by co-immunoprecipitation.In addition,M2E protected ALI induced with LPS against inflammatory and damage which were significantly dependent upon the downregulation of AKT and m TOR via the inhibition of Pla2g2a-EGFR.Pla2g2a may represent a potential target for M2E in the improvement of LPS-induced lung injury,which may represent a promising strategy to treat ALI.

Research Progress on the Prevention of Premature Infant Lung Injury and Neonatal Respiratory Support

In the past 40 years,advances in neonatal intensive care unit(NICU)technology have enabled premature infants with lower birth weight and younger gestational age to survive.But with it comes an increase in the incidence of long-term respiratory dysfunction,mainly in the form of bronchopulmonary dysplasia(BPD).Preventing lung injury is crucial for preventing BPD and improving the long-term prognosis of premature infants.Therefore,how to avoid ventilator-associated lung injury has become a focus of clinical and scientific research in premature infants in recent years.This article will elaborate on the susceptibility and pathophysiology of premature infant lung injury,ventilation strategies for preventing lung injury,and new advances in neonatal respiratory support.

Progress in the mechanism of radiation-induced lung injury

Radiation therapy is widely used to treat various thoracic tumors.However,X-rays inevitably cause damage to normal lung tissues while killing tumor cells,leading to the occurrence of radiation-induced lung injury(RILI).Recent data showed that lung cancer has the highest incidence of RILI(5-25%),followed by mediastinal lymphoma(5-10%),and breast cancer(1-5%).®With the progress in research,our understanding of the mechanism of RILI has changed from the traditional hypothesis of“target cell death”to“a continuous process involving multiple cells,”which is dynamic and evolving[Figure 1],In the present review,we summarize the current knowledge of RILI,and discuss the potential limitations of combined radio-immunotherapy.

Inhaled amifostine for the prevention of radiation-induced lung injury

Objective:To alleviate radiation-induced lung injury and prevent the related pneumonitis and pulmonary fibrosis by inhaled amifostine(AMI).Methods:15 Gy 60Coγ-ray irradiation was performed on the thoracic area of rats once to establish the radiation injury model.AMI was intraperitoneally(i.p.)injected or intratracheally(i.t.)administered to the rats 30 min preirradiation.The protective effects of the two AMI administration manners were compared in the aspects of hematopoietic system,lung edema,and histopathological examination,and the mechanisms were explored.Results:Compared to i.p.AMI,i.t.AMI remarkably alleviated radiation-induced lung injury and prevented consequent pneumonitis or pulmonary fibrosis.Specifically,i.t.AMI notably protected white blood cells and platelets,reduced the lung wet/dry weight ratio,and decreased collagen volume fractions compared to the model group(P<0.05),while i.p.AMI showed no significant difference with the model group(P>0.05).The high therapeutic efficiency of i.t.AMI was related to its high antioxidation and anti-inflammation effects with downregulation of pro-inflammatory cytokines,the enhanced superoxide dismutase activity,the low levels of malondialdehyde and total proteins.Conclusion:Inhaled AMI is a promising medicine for preventing radiation-induced lung injury,including pneumonitis and pulmonary fibrosis.

Periplaneta Americana Extract Ameliorates LPS-induced Acute Lung Injury Via Reducing Inflammation and Oxidative Stress

Objective Acute lung injury(ALI)is an acute clinical syndrome characterized by uncontrolled inflammation response,which causes high mortality and poor prognosis.The present study determined the protective effect and underlying mechanism of Periplaneta americana extract(PAE)against lipopolysaccharide(LPS)-induced ALI.Methods The viability of MH-S cells was measured by MTT.ALI was induced in BALB/c mice by intranasal administration of LPS(5 mg/kg),and the pathological changes,oxidative stress,myeloperoxidase activity,lactate dehydrogenase activity,inflammatory cytokine expression,edema formation,and signal pathway activation in lung tissues and bronchoalveolar lavage fluid(BALF)were examined by H&E staining,MDA,SOD and CAT assays,MPO assay,ELISA,wet/dry analysis,immunofluorescence staining and Western blotting,respectively.Results The results revealed that PAE obviously inhibited the release of proinflammatory TNF-α,IL-6 and IL-1βby suppressing the activation of MAPK/Akt/NF-κB signaling pathways in LPS-treated MH-S cells.Furthermore,PAE suppressed the neutrophil infiltration,permeability increase,pathological changes,cellular damage and death,pro-inflammatory cytokines expression,and oxidative stress upregulation,which was associated with its blockage of the MAPK/Akt/NF-κB pathway in lung tissues of ALI mice.Conclusion PAE may serve as a potential agent for ALI treatment due to its anti-inflammatory and anti-oxidative properties,which correlate to the blockage of the MAPK/NF-κB and AKT signaling pathways.

Glycolysis and acute lung injury:A review

Acute lung injury is featured as diffuse pulmonary edema and persistent hypoxemia caused by lung or systemic injury.It is believed that these pathological changes are associated with damage to the alveolar epithelium and vascular endothelium,recruitment of inflammatory cells,and inflammatory factor storms.In recent years,the metabolic reprogramming of lung parenchymal cells and immune cells,particularly alterations in glycolysis,has been found to occur in acute lung injury.Inhibition of glycolysis can reduce the severity of acute lung injury.Thus,this review focuses on the interconnection between acute lung injury and glycolysis and the mechanisms of interaction,which may bring hope for the treatment of acute lung injury.

The therapeutic mechanism of dexamethasone in lung injury induced by hydrogen sulfide

The lung is one of the primary target organs of hydrogen sulfide(H2S),as exposure to H2S can cause acute lung injury(ALI)and pulmonary edema.Dexamethasone(Dex)exerts a protective effect on ALI caused by exposure to toxic gases and is commonly used in the clinic;however,the underlying mechanisms remain elusive,and the dose is unclear.Methods:In vivo experiments:divided C57BL6 mice into 6 groups at random,12 in each group.The mice were exposed to H2S for 3 h and 5 or 50 mg/kg Dex pretreated before exposure,sacrificed 12 h later.The morphological changes of HE staining and the ultrastructural changes of lungs under transmission electron microscopy were evaluated.The wet/dry ratio of lung tissue was measured.Bronchial alveolar lavage fluid(BALF)protein content and lung permeability index were detected.The expression of AQP5 protein was measured by immunohistochemistry and Western Blot(WB).In vitro experiments:divided human lung adenocarcinoma cell line A549 into 4 groups.1μmol/L dexamethasone was added to pre-incubation.The WB analyzed the protein of p-ERK1/2,p-JNK,and p-p38 in MAPK pathway after 1 h of NaHS exposure;six hours after NaHS exposure,the AQP5 protein was measured by WB.Results:Dex treatment could significantly attenuate the H2S-induced destruction to the alveolar wall,increase the wet-to-dry weight ratio and decrease pulmonary permeability index,with high-dose dexamethasone seemingly functioning better.Additionally,our previous studies showed that aquaporin 5(AQP 5),a critical protein that regulates water flux,decreased both in a mouse and cell model following the exposure to H2S.This study indicates that tThe decrease in AQP 5 can be alleviated by Dex treatment.Additionally,the mitogen activated protein kinase(MAPK)pathway may be involved in the protective effects of Dex in ALI caused by exposure to H2S since H2Sinduced MAPK activation could be inhibited by Dex.Conclusion:The present results indicate that AQP 5 may be considered a therapeutic target for Dex in H2S or other hazardous gases-induced ALI.

Study of the anti-inflammatory effect of the Traditional Mongolian Medicine Hohgardi-9 in acute lung injury

Background:Hohgardi-9 is a well-known traditional Mongolian drug that relieves cough and removes phlegm.Although it is widely used to treat lung diseases clinically,Hohgardi-9’s bioactive constituents and mechanism of action are unknown.In this study,we explored the bioactive compounds in Hohgardi-9 and the mechanism underlying its therapeutic effect against acute lung injury(ALI).Methods:We obtained the main components of Hohgardi-9 and analyzed the targets related to ALI by searching the traditional Chinese medicine systems pharmacology database and existing literature.Then,we constructed the compound-target network using Cytoscape 3.8.0 software to obtain the bioactive compounds in Hohgardi-9 against ALI.We used a string database to investigate the interaction between the possible protein targets of Hohgardi-9.We also performed Gene Ontology function annotation and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis to predict its anti-ALI mechanism.Further,to verify the therapeutical effects of Hohgardi-9,we used an ALI rat model and analyzed the components of Hohgardi-9 found in the rat plasma using ultra-high-performance liquid chromatography coupled with Q-Exactive mass spectrometry.Results:The network pharmacology and plasma component analysis showed that Hohgardi-9 contained 31 potentially bioactive components,including quercetin,herbacetin,izoteolin,and columbinetin acetate,which affected the NF-κB,TLR,and TNF signaling pathways via key targets,such as RELA(p65)and TLR4.The in vivo experiments using hematoxylin and eosin staining revealed that Hohgardi-9 significantly improved lung tissue injury and pulmonary edema in ALI rats.Simultaneously,Hohgardi-9 significantly reduced the expression levels of genes encoding inflammatory factors,such as TRL4,TNF-α,IL-1β,and ICAM1,in the lungs of ALI rats.Conclusion:Hohgardi-9 alleviated ALI by inhibiting inflammation-related gene expression through its active ingredients,such as quercetin and herbacetin.

Network pharmacology and molecular docking to explore Polygoni Cuspidati Rhizoma et Radix treatment for acute lung injury

BACKGROUND Polygoni Cuspidati Rhizoma et Radix(PCRR),a well-known traditional Chinese medicine(TCM),inhibits inflammation associated with various human diseases.However,the anti-inflammatory effects of PCRR in acute lung injury(ALI)and the underlying mechanisms of action remain unclear.AIM To determine the ingredients related to PCRR for treatment of ALI using multiple databases to obtain potential targets for fishing.METHODS Recognized and candidate active compounds for PCRR were obtained from Traditional Chinese Medicine Systems Pharmacology,STITCH,and PubMed databases.Target ALI databases were built using the Therapeutic Target,DrugBank,DisGeNET,Online Mendelian Inheritance in Man,and Genetic Association databases.Network pharmacology includes network construction,target prediction,topological feature analysis,and enrichment analysis.Bioinformatics resources from the Database for Annotation,Visualization and Integrated Discovery were utilized for gene ontology biological process and Kyoto Encyclopedia of Genes and Genomes network pathway enrichment analysis,and molecular docking techniques were adopted to verify the combination of major active ingredients and core targets.RESULTS Thirteen bioactive compounds corresponding to the 433 PCRR targets were identified.In addition,128 genes were closely associated with ALI,60 of which overlapped with PCRR targets and were considered therapeutically relevant.Functional enrichment analysis suggested that PCRR exerted its pharmacological effects in ALI by modulating multiple pathways,including the cell cycle,cell apoptosis,drug metabolism,inflammation,and immune modulation.Molecular docking results revealed a strong associative relationship between the active ingredient and core target.CONCLUSION PCRR alleviates ALI symptoms via molecular mechanisms predicted by network pharmacology.This study proposes a strategy to elucidate the mechanisms of TCM at the network pharmacology level.

Neuron-specific enolase expression in a rat model of radiation-induced brain injury following vascular endothelial growth factor-modified neural stem cell transplantation

BACKGROUND： Previous studies have shown that transplantation of vascular endothelial growth factor （VEGF）-modified neural stem cells （NSC） provides better outcomes, compared with neural stem cells, in the treatment of brain damage. OBJECTIVE： To compare the effects of VEGF-modified NSC transplantation and NSC transplantation on radiation-induced brain injury, and to determine neuron-specific enolase （NSE） expression in the brain. DESIGN, TIME, AND SETTING： The randomized, controlled study was performed at the Linbaixin Experimental Center, Second Affiliated Hospital, Sun Yat-sen University, China from November 2007 to October 2008. MATERIALS： VEGF-modified C17.2 NSCs were supplied by Harvard Medical School, USA. Streptavidin-biotin-peroxidase-complex kit （Boster, China） and 5, 6-carboxyfluorescein diacetate succinimidyl ester （Fluka, USA） were used in this study. METHODS： A total of 84 Sprague Dawley rats were randomly assigned to a blank control group （n = 20）, model group （n = 20）, NSC group （n = 20）, and a VEGF-modified NSC group （n = 24）. Rat models of radiation-induced brain injury were established in the model, NSC, and VEGF-modified NSC groups. At 1 week following model induction, 10 pL （5 ×10^4 cells/μL） VEGF-modified NSCs or NSCs were respectively infused into the striatum and cerebral cortex of rats from the VEGF-modified NSC and NSC groups. A total of 10μL saline was injected into rats from the blank control and model groups. MAIN OUTCOME MEASURES： NSE expression in the brain was detected by immunohistochemistry following VEGF-modified NSC transplantation. RESULTS： NSE expression was significantly decreased in the brains of radiation-induced brain injury rats （P 〈 0.05）. The number of NSE-positive neurons significantly increased in the NSC and VEGF-modified NSC groups, compared with the model group （P 〈 0.05）. NSE expression significantly increased in the VEGF-modified NSC group, compared with the NSC group, at 6 weeks following transplantation （P 〈 0.05）. CONCLUSION： VEGF-modified NSC transplantation increased NSE expression in rats with radiation-induced brain injury, and the outcomes were superior to NSC transplantation.

Extracellular vesicles in the pathogenesis and treatment of acute lung injury

Acute lung injury(ALI)and acute respiratory distress syndrome(ARDS)are common life-threatening lung diseases associated with acute and severe inflammation.Both have high mortality rates,and despite decades of research on clinical ALI/ARDS,there are no effective therapeutic strategies.Disruption of alveolar-capillary barrier integrity or activation of inflammatory responses leads to lung inflammation and injury.Recently,studies on the role of extracellular vesicles(EVs)in regulating normal and pathophysiologic cell activities,including inflammation and injury responses,have attracted attention.Injured and dysfunctional cells often secrete EVs into serum or bronchoalveolar lavage fluid with altered cargoes,which can be used to diagnose and predict the development of ALI/ARDS.EVs secreted by mesenchymal stem cells can also attenuate inflammatory reactions associated with cell dysfunction and injury to preserve or restore cell function,and thereby promote cell proliferation and tissue regeneration.This review focuses on the roles of EVs in the pathogenesis of pulmonary inflammation,particularly ALI/ARDS.