| 1. |
- Apelgren, Peter, et al.
(författare)
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In Vivo Human Cartilage Formation in Three-Dimensional Bioprinted Constructs with a Novel Bacterial Nanocellulose Bioink
- 2019
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Ingår i: Acs Biomaterials Science & Engineering. - : American Chemical Society (ACS). - 2373-9878. ; 5:5, s. 2482-2490
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Tidskriftsartikel (refereegranskat)abstract
- Bacterial nanocellulose (BNC) is a 3D network of nanofibrils exhibiting excellent biocompatibility. Here, we present the aqueous counter collision (ACC) method of BNC disassembly to create bioink with suitable properties for cartilage-specific 3D-bioprinting. BNC was disentangled by ACC, and fibril characteristics were analyzed. Bioink printing fidelity and shear-thinning properties were evaluated. Cell-laden bioprinted grid constructs (5 X 5 X 1 mm(3)) containing human nasal chondrocytes (10 M mL(-1)) were implanted in nude mice and explanted after 30 and 60 days. Both ACC and hydrolysis resulted in significantly reduced fiber lengths, with ACC resulting in longer fibrils and fewer negative charges relative to hydrolysis. Moreover, ACC-BNC bioink showed outstanding printability, postprinting mechanical stability, and structural integrity. In vivo, cell-laden structures were rapidly integrated, maintained structural integrity, and showed chondrocyte proliferation, with 32.8 +/- 13.8 cells per mm(2) observed after 30 days and 85.6 +/- 30.0 cells per mm(2) at day 60 (p = 0.002). Furthermore, a full-thickness skin graft was attached and integrated completely on top of the 3D-bioprinted construct. The novel ACC disentanglement technique makes BNC biomaterial highly suitable for 3D-bioprinting and clinical translation, suggesting cell-laden 3D-bioprinted ACC-BNC as a promising solution for cartilage repair.
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| 2. |
- Amoroso, Matteo, 1984, et al.
(författare)
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Functional and morphological studies of in vivo vascularization of 3D-bioprinted human fat grafts
- 2021
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Ingår i: Bioprinting. - : Elsevier BV. - 2405-8866. ; 23
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Tidskriftsartikel (refereegranskat)abstract
- Three-dimensional (3D) bioprinting offers the ability to design and biofabricate 3D structures based on autologous fat; however, the lack of vascularization in larger 3D-bioprinted constructs represents a limiting factor that hampers translation of this technology from bench to bedside. 3D bioprinting using microfractured fat mixed with nanocellulose–alginate hydrogel can promote vascularization through connections of fragments of vessels included in the fat. In this study, we determined the perfusion and diffusion characteristics of 3D-bioprinted fat constructs using magnetic resonance imaging (MRI) and assessed correlations between perfusion and angiogenesis within the printed constructs. Microfractured human fat from liposuction was printed with tunicate nanocellulose–alginate hydrogel, followed by transplantation of the constructs (10 × 10 × 3 mm) into nude mice that underwent longitudinal MRI for up to 99 days. Confirmation of vascularization was undertaken using immunohistochemical and histologic analyses. Before implantation, the constructs contained abundant fat tissue and fragments of human blood vessels (CD31+ and Ku80+), with subsequent in vivo MRI analysis following transplantation indicating low perfusion and suggesting their continued survival mainly by diffusion. Additionally, we observed a high diffusion coefficient (~2 × 10−3 mm2/s) that was preserved throughout the observation period. Following explantation, evaluation revealed that the constructs displayed preserved histology along with a mixture of human (Ku80+) and murine (Ku80−) erythrocyte-containing vessels. These results demonstrated successful interconnection of blood-vessel fragments from microfractured human fat via angiogenesis to form a vascular network with the host circulation, thereby confirming vascularization of the 3D-bioprinted fat constructs.
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| 3. |
- Amoroso, Matteo, 1984
(författare)
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Microcirculation in tissue repair - from microsurgery to 3D bioprinting
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Microsurgical reconstruction is challenged by two main shortcomings: Perfusion Related Complication (PRC) and donor site morbidity. In the first 3 studies of this thesis, we aimed to provide solutions to PRC-problems, investigating hemodilution as a tool able to increase blood flow in flap microcirculation. In study I, we investigated the beneficial effect of hemodilution on the blood flow of a perforator free flap in a rat model and in study II, hemodilution was examined in a perforator pedicle flap. Overall, study I and study II showed that hemodilution improved flap survival. Study III, a systematic review of the current literature on hemodilution in microsurgery, demonstrated a lack of relevant clinical research on this topic in both clinical and experimental studies. The second part of this thesis aimed to investigate vascularization in 3D bioprinted constructs, a crucial step for bringing this technology into clinical practice, and thereby contribute to a solution to donor site morbidity. In both study IV (3D bioprinted microfractured fat) and V (3D bioprinted cartilage), the constructs were transplanted to nude mice and examined by longitudinal Magnetic Resonance Imaging, histology and immunohistochemistry. Results showed a perfusable vascular network growing around and into the constructs. In study IV, human blood vessels formed spontaneously from fragments of blood vessels in the lipoaspirate used for bioprinting. The blood vessels interconnected with the circulation of the host. In study V, the grid structure itself proved important for vascularization from the host. To summarize, this thesis shows that hemodilution could improve flap viability in microsurgical reconstructions but there is a lack of support for its effect in clinical studies. Vascularization of 3D bioprinted constructs can be achieved by printing with microfractured human fat. By printing in a gridded structure, vascularization can be further stimulated.
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| 4. |
- Amoroso, Matteo, 1984, et al.
(författare)
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The effect of hemodilution on free flap survival: A systematic review of clinical andexperimental studies.
- 2020
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Ingår i: Clinical hemorheology and microcirculation. - 1875-8622. ; 75:4, s. 457-466
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Forskningsöversikt (refereegranskat)abstract
- Acute normovolemic hemodilution (ANH) has been proposed as a microsurgical technique to improve blood flow in free flaps.Here, we present the first systematic review of clinical and experimental studies on the effect of ANH.We performed a systematic literature search of PubMed, Medline, the Cochrane Library, Google Scholar, and ClinicalTrials.gov using search strategies and a review process in agreement with the PRISMA statement and the Cochrane Handbook for systematic reviews of interventions. PICO criteria were defined before bibliometric processing of the retrieved articles, which were analyzed with the SYRCLE RoB tool for risk of bias and the GRADE scale for level of evidence.We retrieved 74 articles from the literature search, and after processing according to PICO criteria, only four articles remained, all of which were experimental. The rating for risk of bias was uncertain according to SYRCLE RoB results, and the level of evidence was low according to GRADE evaluation.There is no clinical evidence for the effect of ANH on microcirculation in free flaps, and experimental studies provide weak evidence supporting the use of hemodilution in reconstructive microsurgery.
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| 5. |
- Apelgren, Peter, et al.
(författare)
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Chondrocytes and stem cells in 3D-bioprinted structures create human cartilage in vivo.
- 2017
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 12:12
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Tidskriftsartikel (refereegranskat)abstract
- Cartilage repair and replacement is a major challenge in plastic reconstructive surgery. The development of a process capable of creating a patient-specific cartilage framework would be a major breakthrough. Here, we described methods for creating human cartilage in vivo and quantitatively assessing the proliferative capacity and cartilage-formation ability in mono- and co-cultures of human chondrocytes and human mesenchymal stem cells in a three-dimensional (3D)-bioprinted hydrogel scaffold. The 3D-bioprinted constructs (5 × 5 × 1.2 mm) were produced using nanofibrillated cellulose and alginate in combination with human chondrocytes and human mesenchymal stem cells using a 3D-extrusion bioprinter. Immediately following bioprinting, the constructs were implanted subcutaneously on the back of 48 nude mice and explanted after 30 and 60 days, respectively, for morphological and immunohistochemical examination. During explantation, the constructs were easy to handle, and the majority had retained their macroscopic grid appearance. Constructs consisting of human nasal chondrocytes showed good proliferation ability, with 17.2% of the surface areas covered with proliferating chondrocytes after 60 days. In constructs comprising a mixture of chondrocytes and stem cells, an additional proliferative effect was observed involving chondrocyte production of glycosaminoglycans and type 2 collagen. This clinically highly relevant study revealed 3D bioprinting as a promising technology for the creation of human cartilage.
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| 6. |
- Apelgren, Peter, et al.
(författare)
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Long-term in vivo integrity and safety of3D-bioprinted cartilaginous constructs
- 2021
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Ingår i: Journal of Biomedical Materials Research Part B-Applied Biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 109:1, s. 126-136
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Tidskriftsartikel (refereegranskat)abstract
- Long-term stability and biological safety are crucial for translation of 3D-bioprinting technology into clinical applications. Here, we addressed the long-term safety and stability issues associated with 3D-bioprinted constructs comprising a cellulose scaffold and human cells (chondrocytes and stem cells) over a period of 10 months in nude mice. Our findings showed that increasing unconfined compression strength over time significantly improved the mechanical stability of the cell-containing constructs relative to cell-free scaffolds. Additionally, the cell-free constructs exhibited a mean compressive stress and stiffness (compressive modulus) of 0.04 +/- 0.05 MPa and 0.14 +/- 0.18 MPa, respectively, whereas these values for the cell-containing constructs were 0.11 +/- 0.08 MPa (p= .019) and 0.53 +/- 0.59 MPa (p= .012), respectively. Moreover, histomorphologic analysis revealed that cartilage formed from the cell-containing constructs harbored an abundance of proliferating chondrocytes in clusters, and after 10 months, resembled native cartilage. Furthermore, extension of the experiment over the complete lifecycle of the animal model revealed no signs of ossification, fibrosis, necrosis, or implant-related tumor development in the 3D-bioprinted constructs. These findings confirm the in vivo biological safety and mechanical stability of 3D-bioprinted cartilaginous tissues and support their potential translation into clinical applications.
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| 7. |
- Apelgren, Peter, et al.
(författare)
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Skin Grafting on 3D Bioprinted Cartilage Constructs In Vivo
- 2018
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Ingår i: Plastic and Reconstructive Surgery-Global Open. - : Ovid Technologies (Wolters Kluwer Health). - 2169-7574. ; 6:9
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Tidskriftsartikel (refereegranskat)abstract
- Background: Three-dimensional (3D) bioprinting of cartilage is a promising new technique. To produce, for example, an auricle with good shape, the printed cartilage needs to be covered with skin that can grow on the surface of the construct. Our primary question was to analyze if an integrated 3D bioprinted cartilage structure is a tissue that can serve as a bed for a full-thickness skin graft. Methods: 3D bioprinted constructs (10x10x1.2mm) were printed using nanofibrillated cellulose/alginate bioink mixed with mesenchymal stem cells and adult chondrocytes and implanted subcutaneously in 21 nude mice. Results: After 45 days, a full-thickness skin allograft was transplanted onto the constructs and the grafted construct again enclosed subcutaneously. Group 1 was sacrificed on day 60, whereas group 2, instead, had their skin-bearing construct uncovered on day 60 and were sacrificed on day 75 and the explants were analyzed morphologically. The skin transplants integrated well with the 3D bioprinted constructs. A tight connection between the fibrous, vascularized capsule surrounding the 3D bioprinted constructs and the skin graft were observed. The skin grafts survived the uncovering and exposure to the environment. Conclusions: A 3D bioprinted cartilage that has been allowed to integrate in vivo is a sufficient base for a full-thickness skin graft. This finding accentuates the clinical potential of 3D bioprinting for reconstructive purposes.
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| 8. |
- Apelgren, Peter, et al.
(författare)
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Vascularization of tissue engineered cartilage-Sequential in vivo MRI display functional blood circulation
- 2021
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Ingår i: Biomaterials. - : Elsevier BV. - 0142-9612 .- 1878-5905. ; 276
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Tidskriftsartikel (refereegranskat)abstract
- Establishing functional circulation in bioengineered tissue after implantation is vital for the delivery of oxygen and nutrients to the cells. Native cartilage is avascular and thrives on diffusion, which in turn depends on proximity to circulation. Here, we investigate whether a gridded three-dimensional (3D) bioprinted construct would allow ingrowth of blood vessels and thus prove a functional concept for vascularization of bioengineered tissue. Twenty 10 x 10 x 3-mm 3Dbioprinted nanocellulose constructs containing human nasal chondrocytes or cell-free controls were subcutaneously implanted in 20 nude mice. Over the next 3 months, the mice were sequentially imaged with a 7 T small-animal MRI system, and the diffusion and perfusion parameters were analyzed. The chondrocytes survived and proliferated, and the shape of the constructs was well preserved. The diffusion coefficient was high and well preserved over time. The perfusion and diffusion patterns shown by MRI suggested that blood vessels develop over time in the 3D bioprinted constructs; the vessels were confirmed by histology and immunohistochemistry. We conclude that 3D bioprinted tissue with a gridded structure allows ingrowth of blood vessels and has the potential to be vascularized from the host. This is an essential step to take bioengineered tissue from the bench to clinical practice.
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| 9. |
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| 10. |
- Lewin, Richard, 1976, et al.
(författare)
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The Aesthetically Ideal Position of the Nipple-Areola Complex on the Breast.
- 2016
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Ingår i: Aesthetic plastic surgery. - : Springer Science and Business Media LLC. - 1432-5241 .- 0364-216X. ; 40:5, s. 724-32
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Tidskriftsartikel (refereegranskat)abstract
- Several studies have attempted to identify an objective description of the aesthetically ideal breast, but they have all suffered in their reliability because of having several intrinsic limitations. It is therefore essential to design a template of ideal breast features in order to predict and evaluate aesthetic outcomes in both reconstructive and cosmetic breast surgery. The aim of this study was to determine the aesthetically preferred position of the nipple-areola complex on the breast.
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| 11. |
- Lewin, Richard, 1976, et al.
(författare)
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The Aesthetically Ideal Position of the Nipple-Areola Complex on the Breast
- 2020
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Ingår i: AESTHETIC PLASTIC SURGERY. - : Springer Science and Business Media LLC. - 0364-216X .- 1432-5241. ; 44:4, s. 1130-1138
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Tidskriftsartikel (refereegranskat)abstract
- Background Several studies have attempted to identify an objective description of the aesthetically ideal breast, but they have all suffered in their reliability because of having several intrinsic limitations. It is therefore essential to design a template of ideal breast features in order to predict and evaluate aesthetic outcomes in both reconstructive and cosmetic breast surgery. The aim of this study was to determine the aesthetically preferred position of the nipple- areola complex on the breast. Methods A questionnaire was sent by regular mail to 1000 men and 1000 women aged between 16 and 74 years. They were asked to rank the attractiveness of a series of breasts of women in images with different NAC positions. The images showed breasts from two different angles: 12 frontal-view images with both breasts shown, and five sideview images with only one breast shown. All of the breasts had equal dimensions and proportions, with the same areola size but different NAC positions. Statistical analysis of data was carried out. Results Eight hundred and thirteen of 2000 participants completed the questionnaire. The NAC placement preferred by both genders had a ratio of 40:60 x and 50:50 y, which means that it was best situated in the middle of the breast gland vertically and slightly lateral to the midpoint horizontally. Significant differences were found between the age and gender subgroup preferences. Conclusions This study identified the preferred position of the nipple-areola complex on the female breast in the general population. This is an important information when planning breast reconstructive and cosmetic surgery.
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| 12. |
- Möller, Thomas, 1986, et al.
(författare)
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In Vivo Chondrogenesis in 3D Bioprinted Human Cell-laden Hydrogel Constructs
- 2017
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Ingår i: Plastic and Reconstructive Surgery - Global Open. - 2169-7574 .- 0032-1052 .- 1529-4242. ; 5:2, s. Article no e1227 -
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Tidskriftsartikel (refereegranskat)abstract
- Background: The three-dimensional (3D) bioprinting technology allows creation of 3D constructs in a layer-by-layer fashion utilizing biologically relevant materials such as biopolymers and cells. The aim of this study is to investigate the use of 3D bioprinting in a clinically relevant setting to evaluate the potential of this technique for in vivo chondrogenesis. Methods: Thirty-six nude mice (Balb-C, female) received a 5-x 5-x 1-mm piece of bioprinted cell-laden nanofibrillated cellulose/alginate construct in a subcutaneous pocket. Four groups of printed constructs were used: (1) human (male) nasal chondrocytes (hNCs), (2) human (female) bone marrow-derived mesenchymal stem cells (hBMSCs), (3) coculture of hNCs and hBMSCs in a 20/80 ratio, and (4) Cell-free scaffolds (blank). After 14, 30, and 60 days, the scaffolds were harvested for histological, immunohistochemical, and mechanical analysis. Results: The constructs had good mechanical properties and keep their structural integrity after 60 days of implantation. For both the hNC constructs and the cocultured constructs, a gradual increase of glycosaminoglycan production and hNC proliferation was observed. However, the cocultured group showed a more pronounced cell proliferation and enhanced deposition of human collagen II demonstrated by immunohistochemical analysis. Conclusions: In vivo chondrogenesis in a 3D bioprinted human cell-laden hydrogel construct has been demonstrated. The trophic role of the hBMSCs in stimulating hNC proliferation and matrix deposition in the coculture group suggests the potential of 3D bioprinting of human cartilage for future application in reconstructive surgery.
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| 13. |
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| 14. |
- Säljö, Karin, 1981, et al.
(författare)
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Long-term in vivo survival of 3D-bioprinted human lipoaspirate-derived adipose tissue: proteomic signature and cellular content
- 2022
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Ingår i: Adipocyte. - : Informa UK Limited. - 2162-397X .- 2162-3945. ; 11:1, s. 34-46
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Tidskriftsartikel (refereegranskat)abstract
- Three-dimensional (3D)-bioprinted lipoaspirate-derived adipose tissue (LAT) is a potential alternative to lipo-injection for correcting soft-tissue defects. This study investigated the long-term in vivo survival of 3D-bioprinted LAT and its proteomic signature and cellular composition. We performed proteomic and multicolour flow cytometric analyses on the lipoaspirate and 3D-bioprinted LAT constructs were transplanted into nude mice, followed by explantation after up to 150 days. LAT contained adipose-tissue-derived stem cells (ASCs), pericytes, endothelial progenitor cells (EPCs) and endothelial cells. Proteomic analysis identified 6,067 proteins, including pericyte markers, adipokines, ASC secretome proteins, proangiogenic proteins and proteins involved in adipocyte differentiation and developmental morphogenic signalling, as well as proteins not previously described in human subcutaneous fat. 3D-bioprinted LAT survived for 150 days in vivo with preservation of the construct shape and size. Furthermore, we identified human blood vessels after 30 and 150 days in vivo, indicating angiogenesis from capillaries. These results showed that LAT has a favourable proteomic signature, contains ASCs, EPCs and blood vessels that survive 3D bioprinting and can potentially facilitate angiogenesis and successful autologous fat grafting in soft-tissue reconstruction.
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| 15. |
- Ulker, Pinar, et al.
(författare)
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LDOES ischemic preconditioning increase flap survival by ADORA2B receptor activation?
- 2020
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Ingår i: Clinical hemorheology and microcirculation. - 1875-8622. ; 75:2, s. 151-162
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Tidskriftsartikel (refereegranskat)abstract
- Ischemic preconditioning (IPC) is defined as raising tolerance to subsequent ischemic stress by exposing tissues to sub-lethal ischemia. Although many candidates have been suggested, recent studies have clearly demonstrated that adenosine-mediated ADORA2B receptor (ADORA2BR) activation is the main mechanism involved in IPC. While the tissue-protective role of this mechanism has been demonstrated in different ischemia/reperfusion (I/R) models, its role in flap surgery-derived I/R damage has not to date been investigated.To investigate the role of adenosine and ADORA2BR activation in IPC-mediated tissue protection in an epigastric flap model.Animals were divided into five main groups, all of which were then divided into two subgroups depending on whether or not they were exposed to IPC before the I/R procedure, which consisted of 6 hours of ischemia and 6 days of reperfusion. No drugs were administered in Group 1 (the control group). Animals in Group 2 were pretreated with CD73-inhibitor before IPC application or the ischemic period. Animals in Group 3 were pretreated with adenosine. Animals in Group 4 were pretreated with an ADORA2BR antagonist, and those in Group 5 with an ADORA2BR agonist. After 6 days of reperfusion, tissue survival was evaluated via histological and macroscopic analysis.IPC application significantly enhanced CD73 expressions and adenosine concentrations (p<0.01). Flap survivals were increased by IPC in Group 1 (p<0.05). However, CD73 inhibition blocked this increase (Group 2). In Group 3, adenosine improved flap survival even in the absence of IPC (p<0.01). While an ADORA2BR antagonist attenuated the tissue-protective effect of IPC (p<0.01), the ADORA2BR agonist improved flap survival by mimicking IPC in groups 4 and 5.These results provide pharmacological evidence for a contribution of CD73 enzyme-dependent adenosine generation and signaling through ADORA2BR to IPC-mediated tissue protection. They also suggest for the first time that ADORA2BR agonists may be used as a potential preventive therapy against I/R injury in flap surgeries.
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