Nicole M Racca, Alexander Dontu, Kayle Riley, Esma S Yolcu, Haval Shirwan, María M Coronel
{"title":"Bending the Rules: Amplifying PD-L1 Immunoregulatory Function Through Flexible Polyethylene Glycol Synthetic Linkers.","authors":"Nicole M Racca, Alexander Dontu, Kayle Riley, Esma S Yolcu, Haval Shirwan, María M Coronel","doi":"10.1089/ten.TEA.2023.0274","DOIUrl":"10.1089/ten.TEA.2023.0274","url":null,"abstract":"<p><p>Immune checkpoint signaling, such as programmed cell death protein-1 (PD-1), is a key target for immunotherapy due to its role in dampening immune responses. PD-1 signaling in T cells is regulated by complex physicochemical and mechanical cues. However, how these mechanical forces are integrated with biochemical responses remains poorly understood. Our previous work demonstrated that the use of an immobilizing polyethylene glycol (PEG) linker on synthetic microgels for the presentation of a chimeric form of PD-L1, SA-PD-L1, lead to local regulatory responses capable of abrogating allograft rejection in a model of cell-based transplantation. We herein provide evidence that enhanced immune regulating function can be obtained when presentation of SA-PD-L1 is achieved through a longer more flexible PEG chain. Presentation of SA-PD-L1 through a linker of high molecular weight, and thus longer length (10 kDa, 60 nm in length), led to enhance conversion of naive T cells into T regulatory cells (Tregs) <i>in vitro</i>. In addition, using a subcutaneous implant model and protein tethered through three different linker sizes (6, 30, and 60 nm) to the surface of PEG hydrogels, we demonstrated that longer linkers promoted PD-1 immunomodulatory role <i>in vivo</i> through three main functions: (1) augmenting immune cell recruitment at the transplant site; (2) promoting the accumulation of naive Tregs expressing migratory markers; and (3) dampening CD8<sup>+</sup> cytolytic molecule production while augmenting expression of exhaustion phenotypes locally. Notably, accumulation of Treg cells at the implant site persisted for over 30 days postimplantation, an effect not observed when protein was presented with the shorter version of the linkers (6 and 30 nm). Collectively, these studies reveal a facile approach by which PD-L1 function can be modulated through external tuning of synthetic presenting linkers. Impact statement Recently, there has been a growing interest in immune checkpoint molecules as potential targets for tolerance induction, including programmed cell death protein-1 (PD-1). However, how the mechanics of ligand binding to PD-1 receptor affect downstream activation signaling pathways remains unresolved. By taking advantage of the effect of polyethylene glycol chain length on molecule kinetics in an aqueous solution, we herein show that PD-L1 function can be amplified by adjusting the length of the grafting linker. Our results uncover a potential facile mechanism that can be exploited to advance the role of immune checkpoint ligands, in particular PD-L1, in tolerance induction for immunosuppression-free cell-based therapies.</p>","PeriodicalId":56375,"journal":{"name":"Tissue Engineering Part A","volume":" ","pages":"299-313"},"PeriodicalIF":4.1,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139693651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of Cell Density of a Methacrylic Acid-Based Hydrogel Implant on Embedded Islet Function and Viability.","authors":"Krystal Ortaleza, Michael V Sefton","doi":"10.1089/ten.TEA.2023.0155","DOIUrl":"10.1089/ten.TEA.2023.0155","url":null,"abstract":"<p><p>Subcutaneous delivery of islets in a methacrylic acid-based hydrogel may offer a functional cure for type 1 diabetes. Here we show in mice that the hydrogel is able to provide sufficient vasculature to support islet function and viability, when islets are used at a low islet volume fraction (i.e., cell density). The Krogh cylinder model was used to mathematically estimate the effect of implant volume, for a fixed islet dose (600 islet equivalents [IEQ]), on the minimum vessel density required to maintain sufficient pO<sub>2</sub> within the graft. Modeling suggested that 200 μL implants would have low enough islet densities and enough vessels to have islets remain viable, but that 50 μL implants would not; this was confirmed experimentally through measurement of glucose level in streptozotocin-induced diabetic severe combined immunodeficiency disease (SCID/bg) mice, comparing 200 and 50 μL implants, both with 600 IEQ. Vessel densities were ∼20-30 vessels/mm<sup>2</sup> independent of implant volume and vessels were sufficient to increase subcutaneous oxygen tension, as measured with microcapsules containing oxygen sensitive material (a platinum [Pt] porphyrin); both these results were determined without cells. These results are useful in thinking about the scale-up of this system to humans: to maintain a low islet density (∼0.5%), many more islets will require attention to the subcutaneous implant configuration to satisfy the oxygen needs of the cells.</p>","PeriodicalId":56375,"journal":{"name":"Tissue Engineering Part A","volume":" ","pages":"204-213"},"PeriodicalIF":4.1,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92157560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Roxanna E Abhari, Sarah J B Snelling, Edyta Augustynak, Simon Davis, Roman Fischer, Andrew J Carr, Pierre-Alexis Mouthuy
{"title":"A Hybrid Electrospun-Extruded Polydioxanone Suture for Tendon Tissue Regeneration.","authors":"Roxanna E Abhari, Sarah J B Snelling, Edyta Augustynak, Simon Davis, Roman Fischer, Andrew J Carr, Pierre-Alexis Mouthuy","doi":"10.1089/ten.TEA.2023.0273","DOIUrl":"10.1089/ten.TEA.2023.0273","url":null,"abstract":"<p><p>Many surgical tendon repairs fail despite advances in surgical materials and techniques. Tendon repair failure can be partially attributed to the tendon's poor intrinsic healing capacity and the repurposing of sutures from other clinical applications. Electrospun materials show promise as a biological scaffold to support endogenous tendon repair, but their relatively low tensile strength has limited their clinical translation. It is hypothesized that combining electrospun fibers with a material with increased tensile strength may improve the suture's mechanical properties while retaining biophysical cues necessary to encourage cell-mediated repair. This article describes the production of a hybrid electrospun-extruded suture with a sheath of submicron electrospun fibers and a core of melt-extruded fibers. The porosity and tensile strength of this hybrid suture is compared with an electrospun-only braided suture and clinically used sutures Vicryl and polydioxanone (PDS). Bioactivity is assessed by measuring the adsorbed serum proteins on electrospun and melt-extruded filaments using mass spectrometry. Human hamstring tendon fibroblast attachment and proliferation were quantified and compared between the hybrid and control sutures. Combining an electrospun sheath with melt-extruded cores created a hybrid braid with increased tensile strength (70.1 ± 0.3N) compared with an electrospun only suture (12.9 ± 1 N, <i>p</i> < 0.0001). The hybrid suture had a similar force at break to clinical sutures, but lower stiffness and stress. The Young's modulus was 772.6 ± 32 MPa for the hybrid suture, 1693.0 ± 69 MPa for PDS, and 3838.0 ± 132 MPa for Vicryl, <i>p</i> < 0.0001. Hybrid sutures had lower overall porosity than electrospun-only sutures (40 ± 4% and 60 ± 7%, respectively, <i>p</i> = 0.0018) but had a significantly larger overall porosity and average pore diameter compared with surgical sutures. There were similar clusters of adsorbed proteins on electrospun and melt-extruded filaments, which were distinct from PDS. Tendon fibroblast attachment and cell proliferation on hybrid and electrospun sutures were significantly higher than on clinical sutures. This study demonstrated that a bioactive suture with increased tensile strength and lower stiffness could be produced by adding a core of 10 μm melt-extruded fibers to a sheath of electrospun fibers. In contrast to currently used sutures, the hybrid sutures promoted a bioactive response: serum proteins adsorbed, and fibroblasts attached, survived, grew along the sutures, and adopted appropriate morphologies.</p>","PeriodicalId":56375,"journal":{"name":"Tissue Engineering Part A","volume":" ","pages":"214-224"},"PeriodicalIF":4.1,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10954604/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138833215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lauren E Mehanna, Adrianna R Osborne, Charlotte A Peterson, Brad J Berron
{"title":"Spontaneous Alignment of Myotubes Through Myogenic Progenitor Cell Migration.","authors":"Lauren E Mehanna, Adrianna R Osborne, Charlotte A Peterson, Brad J Berron","doi":"10.1089/ten.TEA.2023.0177","DOIUrl":"10.1089/ten.TEA.2023.0177","url":null,"abstract":"<p><p>In large-volume muscle injuries, widespread damage to muscle fibers and the surrounding connective tissue prevents myogenic progenitor cells (MPCs) from initiating repair. There is a clinical need to rapidly fabricate large muscle tissue constructs for integration at the site of large volume muscle injuries. Most strategies for myotube alignment require microfabricated structures or prolonged orientation times. We utilize the MPC's natural propensity to close gaps across an injury site to guide alignment on collagen I. When MPCs are exposed to an open boundary free of cells, they migrate unidirectionally into the cell-free region and align perpendicular to the original boundary direction. We study the utility of this phenomenon with biotin-streptavidin adhesion to position the cells on the substrate, and then demonstrate the robustness of this strategy with unmodified cells, creating a promising tool for MPC patterning without interrupting their natural function. We preposition MPCs in straight-line patterns separated with small gaps. This temporary positioning initiates the migratory nature of the MPCs to align and form myotubes across the gaps, similar to how they migrate and align with a single open boundary. There is a directional component to the MPC migration perpendicular (90°) to the original biotin-streptavidin surface patterns. The expression of myosin heavy chain, the motor protein of muscle thick filaments, is confirmed through immunocytochemistry in myotubes generated from MPCs in our patterning process, acting as a marker of skeletal muscle differentiation. The rapid and highly specific binding of biotin-streptavidin allows for quick formation of temporary patterns, with MPC alignment based on natural regenerative behavior rather than complex fabrication techniques.</p>","PeriodicalId":56375,"journal":{"name":"Tissue Engineering Part A","volume":" ","pages":"192-203"},"PeriodicalIF":4.1,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138453223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cassandra Reed, Tai Huynh, Jacob Schluns, Payton Phelps, Jamie Hestekin, Jeffrey C Wolchok
{"title":"Cell-Derived Extracellular Matrix Fiber Scaffolds Improve Recovery from Volumetric Muscle Loss.","authors":"Cassandra Reed, Tai Huynh, Jacob Schluns, Payton Phelps, Jamie Hestekin, Jeffrey C Wolchok","doi":"10.1089/ten.TEA.2022.0227","DOIUrl":"10.1089/ten.TEA.2022.0227","url":null,"abstract":"<p><p>There are currently no surgical procedures that effectively address the treatment of volumetric muscle loss (VML) injuries that has motivated the development of implantable scaffolding. In this study, the effectiveness of an allogenic scaffold fabricated using fibers built from the extracellular matrix (ECM) collected from muscle fibroblast cells during growth in culture was explored using a hindlimb VML injury (tibialis anterior muscle) in a rat model. Recovery outcomes (8 weeks) were explored in comparison with unrepaired controls as well previously examined allogenic scaffolds prepared from decellularized skeletal muscle (DSM) tissue (<i>n</i> = 9/sample group). At 8-week follow-up, we found that the repair of VML injuries using ECM fiber scaffolds in combination with an autogenic mince muscle (MM) paste significantly improved the recovery of peak contractile torque (79% ± 13% of uninjured contralateral muscle) when compared with unrepaired VML controls (57% ± 13%). Similar significant improvements were measured for muscle mass restoration (93% ± 10%) in response to ECM fiber+MM repair when compared with unrepaired VML controls (73% ± 13%). Of note, mass and contractile strength recovery outcomes for ECM fiber scaffolds were not significantly different from DSM+MM repair controls. These <i>in vivo</i> findings support the further exploration of cell-derived ECM fiber scaffolds as a promising strategy for the repair of VML injury with recovery outcomes that compare favorably with current tissue-sourced ECM scaffolds. Furthermore, although the therapeutic potential of ECM fibers as a treatment strategy for muscle injury was explored in this study, they could be adapted for high-throughput fabrication methods developed and routinely used by the textile industry to create a broad range of woven implants (e.g., hernia meshes) for even greater clinical impact.</p>","PeriodicalId":56375,"journal":{"name":"Tissue Engineering Part A","volume":" ","pages":"181-191"},"PeriodicalIF":4.1,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10136247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elana M Meijer, Christian G M van Dijk, Rachel Giles, Karlijn Gijsen, Ihsan Chrifi, Marianne C Verhaar, Caroline Cheng
{"title":"Induction of Fenestrae in Human Induced Pluripotent Stem Cell-Derived Endothelial Cells for Disease Modeling.","authors":"Elana M Meijer, Christian G M van Dijk, Rachel Giles, Karlijn Gijsen, Ihsan Chrifi, Marianne C Verhaar, Caroline Cheng","doi":"10.1089/ten.TEA.2023.0236","DOIUrl":"10.1089/ten.TEA.2023.0236","url":null,"abstract":"<p><p>The endothelial linings of capillaries, such as those in the kidney and small intestines, possess fenestrae that facilitate fluid and exchange of small molecules. Alterations in the size and number of endothelial fenestrae have been implicated in the pathogenesis of various diseases. The re-creation of fenestrated endothelium using human induced pluripotent stem cells (hiPSCs) provides a promising avenue to investigate the involvement of fenestrae in disease mechanisms and pharmacodynamics. In this project, we aim to induce the formation of fenestrae in nonfenestrated hiPSCs-derived endothelial cells (hiPSC-ECs). Vascular endothelial growth factor A (VEGFA) and phorbol myristate acetate (PMA) were used as inducers of fenestrae in hiPSC-ECs. The assessment of fenestrae formation included gene-expression analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and immunofluorescent staining. Endothelial monolayer functionality was evaluated by dextran permeability assays. Stimulation with VEGFA and PMA significantly induced expression of the diaphragmed fenestrae-associated marker, plasmalemmal vesicle-associated protein (PLVAP), in hiPSC-ECs at the mRNA, and protein levels. SEM analysis revealed VEGFA- and PMA-induced fenestrae structures on the cell membrane of hiPSC-ECs. The increased membrane localization of PLVAP visualized by TEM and immunofluorescent staining supported these findings. The induced fenestrated endothelium in hiPSC-ECs demonstrated selective passage of small solutes across a confluent monolayer with intact cell junctions, confirming functional competence. In conclusion, we present a novel methodology for inducing and regulating fenestrated endothelium in hiPSC-ECs. This innovative approach paves the way for the development of fenestrated microvasculature in human organ-on-a-chip systems, enabling complex disease modeling and physiologically relevant investigations of pharmacodynamics.</p>","PeriodicalId":56375,"journal":{"name":"Tissue Engineering Part A","volume":" ","pages":"168-180"},"PeriodicalIF":4.1,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138833217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tissue Engineering Part APub Date : 2024-02-01Epub Date: 2024-01-31DOI: 10.1089/ten.tea.2024.29054.jos
Joseph P Vacanti
{"title":"Thirtieth Anniversary of Tissue Engineering: A Congratulations and a Few Thoughts.","authors":"Joseph P Vacanti","doi":"10.1089/ten.tea.2024.29054.jos","DOIUrl":"10.1089/ten.tea.2024.29054.jos","url":null,"abstract":"","PeriodicalId":56375,"journal":{"name":"Tissue Engineering Part A","volume":" ","pages":"105-106"},"PeriodicalIF":4.1,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139643498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Unraveling the Mechanisms of Vestibular Neuron Formation from Human Induced Pluripotent Stem Cells.","authors":"Benjamin Norton, Analia Quirk, Akihiro J Matsuoka","doi":"10.1089/ten.TEA.2023.0166","DOIUrl":"10.1089/ten.TEA.2023.0166","url":null,"abstract":"<p><p>The development of <i>in vitro</i> models that accurately recapitulate the complex cellular and molecular interactions of the inner ear is crucial for understanding inner ear development, function, and disease. In this study, we utilized a customized microfluidic platform to generate human induced pluripotent stem cell (hiPSC)-derived three-dimensional otic sensory neurons (OSNs). hiPSC-derived otic neuronal progenitors (ONPs) were cultured in hydrogel-embedded microfluidic channels over a 40-day period. Careful modulation of Wnt and Shh signaling pathways was used to influence dorsoventral patterning and direct differentiation toward a vestibular neuron lineage. After validating the microfluidic platform, OSN spheroid transcription factor and protein expression were assessed using real-time quantitative polymerase chain reaction (RT-qPCR), immunocytochemistry, and flow cytometry. The results demonstrated the successful differentiation of hiPSCs into ONPs and subsequent divergent differentiation into vestibular neuronal lineages, as evidenced by the expression of characteristic markers. Overall, our microfluidic platform provides a physiologically relevant environment for the culture and differentiation of hiPSCs, offering a valuable tool for studying inner ear development, disease and drug screening, and regenerative medicine applications.</p>","PeriodicalId":56375,"journal":{"name":"Tissue Engineering Part A","volume":" ","pages":"131-143"},"PeriodicalIF":4.1,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71429605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"LATS1/YAP1 Axis Controls Bone Regeneration on Distraction Osteogenesis by Activating Wnt/β-Catenin.","authors":"Kehan Li, Linan Liu, Hanghang Liu, Jiawei Xing, Pei Hu, Jian Song","doi":"10.1089/ten.TEA.2023.0091","DOIUrl":"10.1089/ten.TEA.2023.0091","url":null,"abstract":"<p><p>The Hippo signaling pathway inhibits cell growth, and its components and functions are highly conserved in mammals. LATS1 is a core component of the Hippo signaling pathway associated with lymphatic invasion, astrogliosis, apoptosis, and autophagy. Nevertheless, the role of Hippo/LATS1 in osteogenesis remains unclear. In this study, we used ribonucleic acid (RNA) lentiviruses to inhibit the expression of <i>Lats1</i> in bone marrow-derived stem cells (BMSCs) and distraction osteogenic regions in rats. Increased osteogenic, proliferative, and migratory abilities of BMSCs were observed in <i>Lats1</i>-inhibited BMSCs, while these phenotypes were partially reversed by YAP1 inhibition. <i>In vivo</i>, we found that the LATS1/YAP1 axis promoted osteogenesis during distraction osteogenesis (DO). β-catenin was positively correlated with YAP1 expression <i>in vivo</i> and <i>in vitro</i>. When YAP1 was strongly positive in the nucleus, β-catenin expression was upregulated; when YAP1 expression was inhibited by verteporfin, β-catenin was not expressed in the nucleus. These findings suggest that the LATS1/YAP1 signaling axis promotes DO by activating the Wnt/β-catenin signaling pathway. This study provides insights into the molecular mechanism of osteogenesis and a potential therapeutic strategy for bone regeneration in DO by associating with LATS1/YAP1-β-catenin.</p>","PeriodicalId":56375,"journal":{"name":"Tissue Engineering Part A","volume":" ","pages":"154-167"},"PeriodicalIF":4.1,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71489480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kazuaki Mito, Jordan Lachnish, Wei Le, Calvin Chan, Yun-Liang Chang, Jeffrey Yao
{"title":"Scaffold-Free Bone Marrow-Derived Mesenchymal Stem Cell Sheets Enhance Bone Formation in a Weight-Bearing Rat Critical Bone Defect Model.","authors":"Kazuaki Mito, Jordan Lachnish, Wei Le, Calvin Chan, Yun-Liang Chang, Jeffrey Yao","doi":"10.1089/ten.TEA.2023.0118","DOIUrl":"10.1089/ten.TEA.2023.0118","url":null,"abstract":"<p><p>Researchers have been exploring alternative methods for bone tissue engineering, as current management of critical bone defects may be a significant challenge for both patient and surgeon with conventional surgical treatments associated with several potential complications and drawbacks. Recent studies have shown mesenchymal stem cell sheets may enhance bone regeneration in different animal models. We investigated the efficacy of implanted scaffold-free bone marrow-derived mesenchymal stem cell (BMSC) sheets on bone regeneration of a critical bone defect in a weight-bearing rat model. BMSCs were isolated from the femora of male Sprague-Dawley rats 5-6 weeks of age and cell sheets were produced on temperature-responsive culture dishes. Nine male Sprague-Dawley rats 6-8 weeks of age were utilized. A bilateral femoral critical bone defect was created with a bridge plate serving as internal fixation. One side was randomly selected and BMSC sheets were implanted into the bone defect (BMSC group), with the contralateral side receiving no treatment (control). Rats were anesthetized and radiographs were performed at 2-week intervals. At the 8-week time point, rats were euthanized, femurs harvested, and microcomputed tomography and histological analysis was performed. We found a statistically significant increase in new bone formation and bone volume fraction compared with the control. Histomorphometry analysis revealed a larger percent of newly formed bone and a higher total histological score. Our results suggest that scaffold-free BMSC sheets may be used in the management of large weight-bearing bone defects to complement a different surgical technique or as a standalone approach followed by internal fixation. However, further research is still needed.</p>","PeriodicalId":56375,"journal":{"name":"Tissue Engineering Part A","volume":" ","pages":"107-114"},"PeriodicalIF":4.1,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138453222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}