RESUMEN
The programmed cell death 1 ligand 1 (PD-L1)/programmed cell death protein 1 (PD-1) axis is primarily associated with immunosuppression in cytotoxic T lymphocytes (CTLs). However, mounting evidence is supporting the thesis that PD-L1 not only functions as a ligand but mediates additional cellular functions in tumor cells. Moreover, it has been demonstrated that PD-L1 is not exclusively localized at the cellular membrane. Subcellular fractionation revealed the presence of PD-L1 in various cellular compartments of six well-characterized head and neck cancer (HNC) cell lines, including the nucleus. Via Western blotting, we detected PD-L1 in its well-known glycosylated/deglycosylated state at 40-55 kDa. In addition, we detected previously unknown PD-L1 variants with a molecular weight at approximately 70 and > 150 kDa exclusively in nuclear protein fractions. These in vitro findings were confirmed with primary tumor samples from head and neck squamous cell carcinoma (HNSCC) patients. Furthermore, we demonstrated that nuclear PD-L1 variant expression is cell-cycle-dependent. Immunofluorescence staining of PD-L1 in different cell cycle phases of synchronized HNC cells supported these observations. Mechanisms of nuclear PD-L1 trafficking remain less understood; however, proximity ligation assays showed a cell-cycle-dependent interaction of the cytoskeletal protein vimentin with PD-L1, whereas vimentin could serve as a potential shuttle for nuclear PD-L1 transportation. Mass spectrometry after PD-L1 co-immunoprecipitation, followed by gene ontology analysis, indicated interaction of nuclear PD-L1 with proteins involved in DNA remodeling and messenger RNA (mRNA) splicing. Our results in HNC cells suggest a highly complex regulation of PD-L1 and multiple tumor cell-intrinsic functions, independent of immune regulation. These observations bear significant implications for the therapeutic efficacy of immune checkpoint inhibition.
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Antígeno B7-H1 , Neoplasias de Cabeza y Cuello , Humanos , Antígeno B7-H1/metabolismo , Ciclo Celular , Neoplasias de Cabeza y Cuello/genética , Carcinoma de Células Escamosas de Cabeza y Cuello/genética , VimentinaRESUMEN
Head and neck squamous cell carcinoma (HNSCC) is an aggressive and difficult-to-treat cancer entity. Current therapies ultimately aim to activate the mitochondria-controlled (intrinsic) apoptosis pathway, but complex alterations in intracellular signaling cascades and the extracellular microenvironment hamper treatment response. On the one hand, proteins of the BCL-2 family set the threshold for cell death induction and prevent accidental cellular suicide. On the other hand, controlling a cell's readiness to die also determines whether malignant cells are sensitive or resistant to anticancer treatments. Here, we show that HNSCC cells upregulate the proapoptotic BH3-only protein NOXA in response to hyperosmotic stress. Induction of NOXA is sufficient to counteract the antiapoptotic properties of MCL-1 and switches HNSCC cells from dual BCL-XL/MCL-1 protection to exclusive BCL-XL addiction. Hypertonicity-induced functional loss of MCL-1 renders BCL-XL a synthetically lethal target in HNSCC, and inhibition of BCL-XL efficiently kills HNSCC cells that poorly respond to conventional therapies. We identify hypertonicity-induced upregulation of NOXA as link between osmotic pressure in the tumor environment and mitochondrial priming, which could perspectively be exploited to boost efficacy of anticancer drugs.
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Carcinoma de Células Escamosas/metabolismo , Neoplasias de Cabeza y Cuello/metabolismo , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/metabolismo , Presión Osmótica/fisiología , Proteína bcl-X/metabolismo , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Apoptosis/genética , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patología , Línea Celular Tumoral , Sinergismo Farmacológico , Neoplasias de Cabeza y Cuello/genética , Neoplasias de Cabeza y Cuello/patología , Humanos , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/antagonistas & inhibidores , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/genética , Proteínas Proto-Oncogénicas c-bcl-2/genética , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Pirimidinas/farmacología , Interferencia de ARN , Tiofenos/farmacología , Microambiente Tumoral/efectos de los fármacos , Proteína bcl-X/antagonistas & inhibidores , Proteína bcl-X/genéticaRESUMEN
Most antineoplastic chemotherapies eliminate cancer cells through activation of the mitochondria-controlled intrinsic apoptotic pathway. Therein, BAX, BAK, and/or BOK function as the essential pore-forming executioners of mitochondrial outer membrane permeabilization (MOMP). The activation threshold of BAX and BAK also correlates inversely with the required strength of an apoptotic stimulus to induce MOMP and thereby effectively determines a cell's readiness to undergo apoptosis. Consequently, the 'gatekeepers' BAX and BAK emerged as therapeutic targets, but functional or genetic loss renders BAX/BAK-targeting strategies prone to fail. Here, we show that the small molecule Raptinal overcomes this limitation by triggering cytochrome c release in a BAX/BAK/BOK-independent manner. Raptinal exerts a dual cytotoxic effect on cancer cells by rapid activation of the intrinsic apoptotic pathway and simultaneous shutdown of mitochondrial function. Together with its efficacy to eliminate cancer cells in vivo, Raptinal could be useful in difficult-to-treat cancer entities harboring defects in the intrinsic apoptosis pathway.
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Apoptosis/efectos de los fármacos , Ciclopentanos/farmacología , Fluorenos/farmacología , Membranas Mitocondriales/metabolismo , Neoplasias/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Proteína Destructora del Antagonista Homólogo bcl-2/metabolismo , Proteína X Asociada a bcl-2/metabolismo , Ciclopentanos/uso terapéutico , Citocromos c/metabolismo , Fluorenos/uso terapéutico , Células HCT116 , Humanos , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Neoplasias/tratamiento farmacológico , Neoplasias/patología , Proteínas Proto-Oncogénicas c-bcl-2/antagonistas & inhibidores , Transducción de Señal/efectos de los fármacos , Proteína Destructora del Antagonista Homólogo bcl-2/genética , Proteína X Asociada a bcl-2/genéticaRESUMEN
Induction of mitochondria-controlled (intrinsic) apoptosis is a mainstay of current anti-neoplastic chemotherapies. Activation of this death pathway is counteracted by BCL-2-like proteins, which functionally set the threshold for apoptosis and determine whether malignant cells are sensitive or resistant to anti-cancer treatments. Hence, unlocking the intrinsic apoptotic cascade and promoting the cell's commitment to undergo apoptosis concordantly promotes efficacy of anti-cancer treatments. Here, we show that hyperosmotic stress enforces addiction of colorectal cancer cells to BCL-XL, thereby exhausting the protective capacity of BCL-2-like proteins and priming mitochondria for death. Our work identifies osmotic pressure as a cell extrinsic factor that modulates responsiveness of colorectal cancer cells to therapy.
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Neoplasias Colorrectales/metabolismo , Presión Osmótica , Interferencia de ARN , Proteína bcl-X/metabolismo , Apoptosis/efectos de los fármacos , Apoptosis/genética , Compuestos de Bifenilo/farmacología , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/genética , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/genética , Células HCT116 , Células HT29 , Humanos , Mitocondrias/efectos de los fármacos , Mitocondrias/genética , Mitocondrias/metabolismo , Nitrofenoles/farmacología , Piperazinas/farmacología , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Sulfonamidas/farmacología , Proteína Destructora del Antagonista Homólogo bcl-2/genética , Proteína Destructora del Antagonista Homólogo bcl-2/metabolismo , Proteína X Asociada a bcl-2/genética , Proteína X Asociada a bcl-2/metabolismo , Proteína bcl-X/genéticaRESUMEN
INTRODUCTION: To assess the discoloration and stain removal potential of different cleaning methods relevant to individual/professional prophylaxis and laboratory cleaning on polyetheretherketone (PEEK), poly(methyl methacrylate) (PMMA)-based, and composite (COMP) materials after storage in different media for 7 days. METHODS: One thousand three hundred twenty specimens of PEEK, PMMA, and COMP (N = 440 of each group) were prepared and stored in four different media for 7 days to cause stain. Samples were divided into three cleaning groups (n = 10): (i) individual prophylaxis, (ii) laboratory protocols, and (iii) professional prophylaxis. Color was determined by a portable spectrophotometer and calculated between different time points (∆E). The data was statistically evaluated using univariate analyses, Kruskal-Wallis H and Mann-Whitney U tests (p < 0.05). RESULTS: The significantly (p < 0.001) lowest discoloration was found when specimens were stored in distilled water and chlorhexidine (CHX), followed by red wine. Curry solution caused the highest discoloration. PEEK showed the significantly (p < 0.001) lowest color changes, while COMP showed the highest changes. Ultrasonic bath and Air Flow Plus (AFP) were the significantly (p < 0.001) most effective methods to remove staining. The least cleaning effect was found using a soft toothbrush (ST), a medium-hard toothbrush (MT), and SunSparkle (SS) cleaning system. CONCLUSIONS: PEEK seems more stable against discolorations than other denture resin materials. Regarding the cleaning potential, individual prophylaxis can be conducted with toothbrushes. For professional prophylaxis, air-abrasion devices using gentle powders are effective. Laboratory protocols should include gentle cleaning methods like ultrasonic bath. CLINICAL RELEVANCE: Clinicians and dental technicians should inform their patients about the discoloration potential of certain foods/beverages and recommend the most efficient cleaning, but preventive methods.
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Resinas Compuestas/química , Materiales Dentales/química , Cetonas/química , Polietilenglicoles/química , Polimetil Metacrilato/química , Decoloración de Dientes , Benzofenonas , Ensayo de Materiales , Polímeros , Coloración de Prótesis , Espectrofotometría , Propiedades de Superficie , Cepillado DentalRESUMEN
STATEMENT OF PROBLEM: Polyetheretherketone (PEEK) can be used as a framework material for fixed dental prostheses. However, information about laboratory and chairside polishing methods is still scarce. PURPOSE: The purpose of this in vitro study was to determine the effects of laboratory and chairside polishing methods on the surface roughness (SR) and surface free energy (SFE) of PEEK, an autopolymerizing poly(methyl methacrylate), and a veneering composite resin. MATERIAL AND METHODS: For each of the 3 materials, 80 specimens were prepared (N=240) and divided into 7 polishing groups and 1 control group (n=10). The 7 groups were split into 4 laboratory protocols: polishing paste (Abraso), a second polishing paste (Opal L), silicone polisher (Ceragum), and diamond grinder (Diagen-Turbo grinder). The other 3 groups were chairside protocols: rainbow technique (Super-Snap kit), polishing paste (Prisma gloss), and a polishing system (Enhance finishing). Machine polishing with SiC P4000 served as the control treatment. The protocols' average SRs and SFEs were measured, and their surface topographies were evaluated with scanning electron microscopy (SEM). The logarithmically transformed data were analyzed using covariance analysis, 2-way and 1-way ANOVA, and partial correlation (α=.05). RESULTS: The polishing protocol exerted the highest influence on SR and SFE values (P<.001; SR: partial eta squared ηP2=.970; SFE: ηP2=.450), followed by material group (P<.001, SR: ηP2=.319; SFE: ηP2=.429). The interaction effect of the binary combinations of the 2 independent parameters (polishing protocol and material group) was also significant (P<.001, SR: ηP2=.681; SFE: ηP2=.365). CONCLUSIONS: Chairside methods presented lower SR values than laboratory methods, and specimens polished using the 2-body mode showed higher SR than did specimens polished using the 3-body mode.
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Pulido Dental/instrumentación , Pulido Dental/métodos , Pulido Dental/normas , Cetonas/química , Polietilenglicoles/química , Propiedades de Superficie , Benzofenonas , Resinas Compuestas , Materiales Dentales/química , Diamante/química , Diseño de Equipo , Humanos , Laboratorios Odontológicos , Ensayo de Materiales , Metilmetacrilato/química , Microscopía Electrónica de Rastreo , Polímeros , Siliconas/químicaRESUMEN
PURPOSE: To determine the effect of different individual, laboratory and professional cleaning methods on the surface-roughness (SR) and surface free energy (SFE) of polyetheretherketone (PEEK), PMMA-based (PMMA) and composite (COMP) materials. METHODS: 330 specimens of PEEK, PMMA and COMP (N = 990) were prepared and divided into the following cleaning protocols (n = 30/group): (i) individual prophylaxis using (ST) soft, (MT) medium-hard and (SOT) sonic toothbrushes, (ii) in-lab cleaning protocols consisting of (SY) Sympro cleaning system, (SS) SunSparkle, (UB) ultrasonic bath and (AP) Al2O3-powder device and (iii) professional prophylaxis applying (PS) Perio Soft-Scaler, (SO) Sonicsys, (AFC) Air Flow Comfort, and (AFP) Air Flow Plus. After each protocol SR (profilometer), SFE (contact angle devise) and surface topography (SEM) were measured. Data were analyzed using multivariate analysis, Kruskal-Wallis-H- and Mann-Whitney-U-test (p<0.05). RESULTS: No impact of material on SR was observed (p = 0.443). Cleaning using conventional air-abrasion and powders (AP), followed by AFC produced higher SR values than the remaining methods (p<0.001). Within SFE, the cleaning method exerted the highest influence on SFE values (p<0.001, ηP2 = 0.246), closely followed by the polymer material (p<0.001, ηP2 = 0.136). PMMA and PEEK presented after cleaning lower SFE than COMP. PS, UB and SO showed lower SFE than specimens cleaned using SS, ST and SY. Cleaning using SY led to the highest SFE. CONCLUSIONS: With regard to SR, all methods - with exception of conventional air-abrasion - can be recommended to clean PEEK. According to the SFE, PEEK may be an acceptable material providing even lower plaque accumulation rates than COMP. The field for more research is now open for scrutiny.
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Cetonas/química , Polietilenglicoles/química , Benzofenonas , Polímeros , Propiedades de SuperficieRESUMEN
Capsular fibrosis is the most frequent long-term complication after insertion of silicone devices. Today, mainly direct immunostimulation and subclinical infection are held responsible for inducing and maintaining inflammatory reactions, which lead to overwhelming extracellular matrix formation. Extracorporeal shock waves (ESWs) are capable of inhibiting inflammatory processes and revealing antibacterial capacity. In our previous study, we observed decelerated capsule development after application of a single shock wave immediately after surgery. The purpose of this study was to evaluate the effects of multiple ESWT after insertion of silicone implants in the same rodent model. Therefore, silicone prostheses were inserted into a submuscular pocket in 12 additional male Lewis rats, and shock waves were administered over a 14-d interval. At 35 d (n = 6) and 100 d (n = 6) after insertion, silicone implants and surrounding capsule tissue were removed and prepared for histologic and immunohistochemical analysis, as well as polymerase chain reaction (Ccl2, CD68, transforming growth factor ß1, matrix metalloproteinase 2). Compared with the control group, multiple ESWT had no effect on day 35, but resulted in a significantly thinner capsule on day 100 (825.8 ± 313.2 vs. 813.3 ± 47.9, p = 0.759, and 1062.3 ± 151.9 vs. 495.4 ± 220.4, p < 0.001, respectively). The capsule was even thinner than after a single shock wave application, which had been found to result in thinner capsules at every time point in our previous study. This active degradation of the fibrous envelope caused by multiple ESWs was accompanied by synergistic alterations in pro- and anti-fibrotic proteins (transforming growth factor ß1 and matrix metalloproteinase 2, respectively). In conclusion, after insertion of silicone devices, single ESWT is capable of decelerating capsule formation in contrast to multiple ESWT, which degrades fibrotic tissue. These findings seem to be associated with inhibition of inflammation and beneficial effects on pro- and anti-fibrotic proteins.
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Ondas de Choque de Alta Energía , Contractura Capsular en Implantes/terapia , Prótesis e Implantes , Animales , Fibrosis/etiología , Fibrosis/terapia , Geles , Inmunohistoquímica , Masculino , Distribución Aleatoria , Ratas , Ratas Endogámicas Lew , SiliconasRESUMEN
UNLABELLED: Capsular contracture remains a major complication after reconstructive or aesthetic breast augmentation. Formation of capsular fibrosis is a multifactorial process. An initial inflammatory reaction appears to be key to the development of capsular contracture. Recent studies have shown that pulsed acoustic cellular expression (PACE) has significant antiinflammatory effects. Thus, this study aimed to determine the potential of PACE to prevent or attenuate capsular contracture around silicone implants in a rodent model. For this study, 36 Lewis rats were divided into two groups, and a textured silicone implant was placed in a dorsal submuscular pocket. One group received PACE treatment, whereas the other group served as the control group and received no treatment. Follow-up evaluations were performed after 10, 35, and 100 days. Capsule thickness, collagen density, myofibroblasts, vascular density, and a semiquantitative real-time polymerase chain reaction that addressed differential gene expression were assessed. The PACE treatment significantly reduced capsule thickness on days 10, 35, and 100 compared with the control group (day 10: 632.9 ± 164.5 vs 932.6 ± 160.8, p < 0.05; day 35: 709.5 ± 175 vs 825.9 ± 313.3, p < 0.0.5; day 100: 736.3 ± 198.1 vs 1,062.3 ± 151.9, p < 0.05). This was accompanied by a significant suppression of proinflammatory genes (cluster of differentiation 68, monocyte chemotactic protein-1, CCL4) and synergistic alterations of pro- and antifibrotic proteins (transforming growth factor-beta 1, matrix metalloproteinase-2). This study showed that the PACE application significantly reduces capsular contracture around silicone implants. A decrease in capsular thickness after PACE treatment seems to be associated with a downregulation of proinflammatory genes and proteins. The study identifies PACE technology as a potential low-cost technique that is easy to use for reduction of capsular contracture after augmentation using silicone implants. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266 .
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Ondas de Choque de Alta Energía , Contractura Capsular en Implantes/prevención & control , Siliconas , Animales , Ratas , Ratas Endogámicas LewRESUMEN
Review of the literature regarding rodent experimental flap models reveals fundamental differences in applied surgical procedures. Although some authors isolate the flap from its wound bed, others do not. This study was planned to investigate to what extent the insertion of a silicone sheet affects physiological wound healing in experimental flap surgery. An extended epigastric adipocutaneous flap (6 × 10 cm) was raised in 16 male Lewis rats. In the control group (group C), flaps were immediately inset without any intervention. In the experimental group (group M), a silicone sheet barrier was placed between the flap and the wound bed. Mean flap survival area and flap perfusion were evaluated. Microvessel density was visualized by immunohistochemistry, and semiquantitative real-time polymerase chain reaction addressed differential gene expression. All animals were investigated on postoperative day 5. Flap survival area and flap perfusion were found to be similar. Immunohistochemistry, however, demonstrated a significantly increased number of CD31-positive small vessels in group C. The insertion of the silicone sheet barrier (group M) was accompanied by a significantly enhanced expression of proinflammatory genes and a suppression of proangiogenic genes. Our results show that although the silicone membrane has no influence on the surgical outcome in terms of flap survival and perfusion, it does lead to significant molecular alterations in pathways involved in physiological wound healing. These alterations are artificially induced by the foreign body material and conceal the true driving forces of the healing process. As the latter might include relevant therapeutic targets to ameliorate surgical results, we regard wound bed isolation as a dispensable procedure in the study of rodent flap models.
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Procedimientos Quirúrgicos Dermatologicos/métodos , Membranas Artificiales , Colgajos Quirúrgicos/irrigación sanguínea , Cicatrización de Heridas , Tejido Adiposo/fisiopatología , Tejido Adiposo/cirugía , Animales , Arterias Epigástricas , Supervivencia de Injerto , Masculino , Necrosis/patología , Distribución Aleatoria , Ratas , Ratas Endogámicas Lew , Siliconas , Piel/patología , Piel/fisiopatología , Colgajos Quirúrgicos/patologíaRESUMEN
BACKGROUND: Advances in the treatment of ischemia- reperfusion injury have created an opportunity for plastic surgeons to apply these treatments to flaps and implanted tissues. We examined the capability of adipose derived stem cells (ADSCs) to protect tissue against IRI using an extended inferior epigastric artery skin flap as a flap ischemia- reperfusion injury (IRI) model. METHODS: ADSCs were isolated from Lewis rats and cultured in vitro. Twenty- four rats were randomly divided into three groups. Group I was the sham group and did not undergo ischemic insult; rather, the flap was raised and immediately sutured back (non-ischemic control group). Group II (ischemia control) and group III (ADSCs treatment) underwent 3 h of ischemic insult. During reperfusion group III was treated by intravenous application of ADSCs and group II was left untreated. Five days postoperatively, flap survival and perfusion were assessed. Microvessel density was visualized by immunohistochemistry and semi- quantitative real-time polymerase chain reaction addressed differential gene expression. RESULTS: Treatment with ADSCs significantly increased flap survival (p<0.001) and flap perfusion (p<0.001) when compared to the control group II. Microvessel- density in ADSCs treated group was not significantly increased in any group. No significant differences showed the comparison of the experimental group III and the sham operated control group I. ADSCs treatment (Group III) was accompanied by a significantly enhanced expression of pro-angiogenic and pro-inflammatory genes. CONCLUSION: Overall, our study demonstrates that ADSCs treatment significantly enhances skin flap survival in the aftermath of ischemia to an extent that almost equals surgical results without ischemia. This effect is accompanied with a pronounced and significant angiogenic response and an improved blood perfusion.
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Grasa Abdominal/patología , Fibrina/química , Trasplante de Células Madre , Células Madre/fisiología , Colgajos Quirúrgicos/patología , Adipogénesis , Proteínas Angiogénicas/genética , Proteínas Angiogénicas/metabolismo , Animales , Antígenos CD/metabolismo , Proliferación Celular , Rastreo Celular , Células Cultivadas , Arterias Epigástricas/metabolismo , Arterias Epigástricas/patología , Expresión Génica , Mediadores de Inflamación/metabolismo , Masculino , Microvasos/patología , Fenotipo , Ratas , Ratas Endogámicas Lew , Colgajos Quirúrgicos/irrigación sanguínea , Andamios del Tejido/químicaAsunto(s)
Grasa Abdominal/patología , Fibrina/química , Daño por Reperfusión/prevención & control , Trasplante de Células Madre , Células Madre/fisiología , Colgajos Quirúrgicos/irrigación sanguínea , Proteínas Angiogénicas/genética , Proteínas Angiogénicas/metabolismo , Animales , Diferenciación Celular , Proliferación Celular , Células Cultivadas , Arterias Epigástricas/metabolismo , Arterias Epigástricas/patología , Expresión Génica , Mediadores de Inflamación/metabolismo , Isquemia/patología , Isquemia/terapia , Masculino , Microvasos/patología , Ratas , Ratas Endogámicas Lew , Daño por Reperfusión/patología , Colgajos Quirúrgicos/patología , Andamios del Tejido/químicaRESUMEN
Advances in the treatment of ischemia-reperfusion injury have created an opportunity for plastic surgeons to apply these treatments to flaps and implanted tissues. Using an extended inferior epigastric artery skin flap as a flap ischemia-reperfusion injury (IRI) model, we examined the capability of extracorporeal shock wave treatment (ESWT) to protect tissue against IRI in a rat flap model. Twenty-four rats were used and randomly divided into three groups (n=8 for each group). Group I was the sham group and did not undergo ischemic insult; rather, the flap was raised and immediately sutured back (non-ischemic control group). Group II (ischemia control) and Group III (ESWT) underwent 3h of ischemic insult. During reperfusion Group III was treated with ESWT and Group II was left untreated. Histological evaluation was made to investigate treatment induced tissue alterations. Survival areas were assessed at 5d postoperatively. Skin flap survival and perfusion improved significantly in the ischemic animals following ESWT (p<0.001, respectively). The tissue protecting effect of ESWT resulted in flap survival areas and perfusion data equal to non-ischemic, sham operated flaps. In line with the observation of better flap perfusion, tissue from ESWT-treated animals (Group III) revealed a significantly increased frequency of CD31-positive vessels compared to both the ischemic (Group II; p=0.003) and the non-ischemic, sham operated control (Group I; p<0.005) and an enhanced expression of pro-angiogenic genes. This was accompanied by a mild suppression of pro-inflammatory genes. Our study suggests that ESWT improves flap survival in IRI by promoting angiogenesis and inhibiting tissue inflammation. The study identifies ESWT as a low-cost and easy to use technique for surgical techniques that aim at reducing ischemia-reperfusion-induced tissue injury.