Bone Tissue Engineering Using Marrow Stromal Cells

Jo, In-Ho,Lee, Jung-Min,Suh, Hwal,Kim, Hyong-Bum Korean Society for Biotechnology and Bioengineerin 2007 Biotechnology and Bioprocess Engineering Vol.12 No.1

Bone tissue defects cause a significant socioeconomic problem, and bone is the most frequently transplanted tissue beside blood. Autografting is considered the gold standard treatment for bone defects, but its utility is limited due to donor site morbidity. Hence, much research has focused on bone tissue engineering as a promising alternative method for repair of bone defects. Marrow stromal cells (MSCs) are considered to be potential cell sources for bone tissue engineering. In bone tissue engineering using MSCs, bone is formed through intramembranous and endochondral ossification in response to osteogenic inducers. Angiogenesis is a complex process mediated by multiple growth factors and is crucial for bone regeneration. Vascular endothelial growth factor plays important roles in bone tissue regeneration by promoting the migration and differentiation of osteoblasts, and by inducing angiogenesis. Scaffold materials used for bone tissue engineering include natural components of bone, such as calcium phosphate and collagen I, and biodegradable polymers such as poly(lactide-coglycolide). However, ideal scaffolds for bone tissue engineering have yet to be found. Bone tissue engineering has been successfully used to treat bone defects in several human clinical trials to regenerate bone defects. Through investigation of MSC biology and the development of novel scaffolds, we will be able to develop advanced bone tissue engineering techniques in the future.

Diffusion of bioactive molecules through the walls of the medial tissue-engineered hybrid ePTFE grafts for applications in designs of vascular tissue regeneration

Noh, Insup,Choi, Yoon-Jeong,Son, Youngsook,Kim, Chun-Ho,Hong, Seung-Hwa,Hong, Choong-Man,Shin, In-Soo,Park, Sue-Nie,Park, Beom-Young Wiley Subscription Services, Inc., A Wiley Company 2006 Journal of biomedical materials research. Part A Vol.a79 No.4

<P>Strategies of better vascular tissue engineering may require delivery of soluble bioactive signals in cell culture medium to the cells in tissue-regenerating constructs. We measured the diffusivity and permeability of model tissue-engineering bioactive molecules such as water and heparin through the walls of both a hybrid ePTFE graft and a porcine carotid artery, a model vascular tissue. While diffusivities of H<SUP>3</SUP>-water and H<SUP>3</SUP>-heparin were measured as 3.9 × 10<SUP>−</SUP><SUP>6</SUP> and 1.6 × 10<SUP>−</SUP><SUP>6</SUP> cm<SUP>2</SUP>/s in the artery, respectively, under diffusional circulation of cell culture medium through the lumens of the carotid arteries, their corresponding permeabilities were 4.7 × 10<SUP>−</SUP><SUP>5</SUP> and 2.0 × 10<SUP>−</SUP><SUP>5</SUP> cm/s. On the other hand, diffusivities of H<SUP>3</SUP>-water and H<SUP>3</SUP>-heparin were also measured as 5.1 × 10<SUP>−</SUP><SUP>6</SUP> and 4.7 × 10<SUP>−</SUP><SUP>6</SUP> cm<SUP>2</SUP>/s, respectively, in the tissue-engineered hybrid ePTFE grafts; their corresponding permeabilities were 5.1 × 10<SUP>−</SUP><SUP>5</SUP> and 3.7 × 10<SUP>−</SUP><SUP>5</SUP> cm/s. The hybrid graft tissues were engineered by replacing the biodegradable, porous poly(lactide-co-glycolide) layers coated on the ePTFE surfaces with smooth muscle cell-derived tissues for 6 weeks. We analyzed the morphologies of the artery and the engineered hybrid ePTFE tissues with scanning electron microscopy and H&E stains. While the artery had its typical structure properties with layers of intima, media and adventitia, the tissue-engineered ePTFE hybrid graft had two layers of engineered tissues on the inner and outer surfaces of the ePTFE. There were no significant differences among the luminal tissue morphologies of the test samples from the effects of diffusion flow applications, with minor changes on their luminal surfaces. The results of water and heparin diffusion experiments indicated that these bioactive molecules were well transported from the cell culture medium to the tissue-engineering cells, enough to support tissue regeneration. We hope that these transport results may elucidate the transport behaviors of soluble nutrient molecules and biological signals through the vascular constructs under tissue engineering processes. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006</P>

Multilayered Engineered Tissue Sheets for Vascularized Tissue Regeneration

홍소영,정보영,황창모 한국조직공학과 재생의학회 2017 조직공학과 재생의학 Vol.14 No.4

A major hurdle in engineering thick and laminated tissues such as skin is how to vascularize the tissue. This study introduces a promising strategy for generatingmulti-layering engineered tissue sheets consisting of fibroblasts and endothelial cells co-seeded on highly micro-fibrous, biodegradable polycaprolactone membrane. Analysis of the conditions for induction of the vessels in vivo showed that addition of endothelial cell sheets into the laminated structure increases the number of incorporated cells and promotes primitive endothelial vessel growth. In vivo analysis of 11-layered constructs showed that seeding a high number of endothelial cells resulted in better cell survival and vascularization 4 weeks after implantation.Within one week after implantation in vivo, red blood cells were detected in the middle section of three-layered engineered tissue sheets composed of polycaprolactone/ collagen membranes. Our engineered tissue sheets have several advantages, such as easy handling for cell seeding, manipulation by stacking each layer, a flexible number of cells for next-step applications and versatile tissue regeneration, and automated thick tissue generation with proper vascularization.

Vascularization of Microvascular Fragment Isolates from Visceral and Subcutaneous Adipose Tissue of Mice

Später Thomas,Marschall Julia E.,Brücker Lea K.,Nickels Ruth M.,Metzger Wolfgang,Menger Michael D.,Laschke Matthias W. 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.1

BACKGROUND: Adipose tissue-derived microvascular fragments (MVF) represent effective vascularization units for tissue engineering. Most experimental studies in rodents exclusively use epididymal adipose tissue as a visceral fat source for MVF isolation. However, in future clinical practice, MVF may be rather isolated from liposuctioned subcutaneous fat tissue of patients. Therefore, we herein compared the vascularization characteristics of MVF isolates from visceral and subcutaneous fat tissue of murine origin. METHODS: MVF isolates were generated from visceral and subcutaneous fat tissue of donor mice using two different enzymatic procedures. For in vivo analyses, the MVF isolates were seeded onto collagen-glycosaminoglycan scaffolds and implanted into full-thickness skin defects within dorsal skinfold chambers of recipient mice. RESULTS: By means of the two isolation procedures, we isolated a higher number of MVF from visceral fat tissue when compared to subcutaneous fat tissue, while their length distribution, viability and cellular composition were comparable in both groups. Intravital fluorescence microscopy as well as histological and immunohistochemical analyses revealed a significantly reduced vascularization of implanted scaffolds seeded with subcutaneous MVF isolates when compared to implants seeded with visceral MVF isolates. Light and scanning electron microscopy showed that this was due to high amounts of undigested connective tissue within the subcutaneous MVF isolates, which clogged the scaffold pores and prevented the interconnection of individual MVF into new microvascular networks. CONCLUSION: These findings indicate the need for improved protocols to generate connective tissue-free MVF isolates from subcutaneous fat tissue for future translational studies.

무세포혈관과 자가 골수줄기세포를 이용한 조직공학적 인공혈관 제조

김동익,김병수,조승우,임정은,어현선,이민재,김종성,장인성 대한혈관외과학회 2004 Vascular Specialist International Vol.20 No.1

Enhancement of in vivo endothelialization of tissue-engineered vascular grafts by granulocyte colony-stimulating factor

Cho, Seung-Woo,Lim, Joung Eun,Chu, Hun Su,Hyun, Hye-Jin,Choi, Cha Yong,Hwang, Ki-Chul,Yoo, Kyung Jong,Kim, Dong-Ik,Kim, Byung-Soo Wiley Publishers 2006 Journal of Biomedical Materials Research Part A Vol. No.

<P>Successful reconstruction of large-diameter blood vessel in humans has been demonstrated using the tissue engineering technique, but improvement in patency of small-diameter bioartificial vascular graft remains a great challenge. This study reports that granulocyte colony-stimulating factor (G-CSF) can enhance in vivo endothelialization of tissue-engineered vascular grafts, which could be used to improve patency of small-diameter vascular graft. Vascular grafts were tissue engineered with decellularized canine abdominal aortas and canine autologous bone marrow–derived cells. Prior to cell seeding onto decellularized graft matrices, bone marrow–derived cells were induced to differentiate into endothelial cells and smooth muscle cells. The cell-seeded vascular grafts were implanted into the abdominal aortas of bone marrow donor dogs. Before and after graft implantation, G-CSF was administered subcutaneously to the dogs (n = 3). The grafts implanted into the dogs not receiving G-CSF were used as controls (n = 3). Eight weeks after implantation, grafts in both groups showed regeneration of vascular tissues including endothelium and smooth muscle. Importantly, endothelium formation was more extensive in the G-CSF–treated grafts than in the control grafts, as assessed with reverse transcription polymerase chain reaction, western blot, and immunohistochemistry. In addition, intimal hyperplasia was significantly reduced in the G-CSF–treated grafts compared to the control grafts. This study suggests that G-CSF administration could be applied to improve patency of small-diameter tissue-engineered vascular grafts. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006</P>

In Vivo Observation of Endothelial Cell-Assisted Vascularization in Pancreatic Cancer Xenograft Engineering

정보영,홍소영,김송철,황창모 한국조직공학과 재생의학회 2018 조직공학과 재생의학 Vol.15 No.3

In this study, for better understanding of patient-derived xenograft (PDX) generation, angiogenic characteristics during PDX cancerous tissue generation was investigated with different initial cell seeding conditions in the hydrogel. We monitored the angiogenic changes during the formation of in vivo cancer cell line xenografts induced by endothelial cells. Our in vivo cancer tissue formation system was designed with the assistance of tissue engineering technology to mimic patient-derived xenograft formation. Endothelial cells and MIA PaCa-2 pancreatic carcinoma cells were encapsulated in fibrin gel at different mixing configurations and subcutaneously implanted into nude mice. To investigate the effect of the initial cancerous cell distribution in the fibrin gel, MIA PaCa-2 cells were encapsulated as a homogeneous cell distribution or as a cell aggregate, with endothelial cells homogeneously distributed in the fibrin gel. Histological observation of the explanted tissues after different implantation periods revealed three different stages: isolated vascular tubes, leaky blood vessels, and mature cancerous tissue formation. The in vivo engineered cancerous tissues had leaky blood vessels with low expression of the vascular tight junction marker CD31. Under our experimental conditions, complex cancer-like tissue formation was most successful when tumorous cells and endothelial cells were homogeneously mixed in the fibrin gel. The present study implies that tumorous xenograft tissue formation can be achieved with a low number of initial cells and that effective vascularization conditions can be attained with a limited volume of patient-derived cancer tissue. Endothelial cellassisted vascularization can be a potent choice for the effective development of vascularized cancerous tissues for studying patient-derived xenografts, cancer angiogenesis, cancer metastasis, and anticancer drugs.

Scaffold Engineering with Flavone-Modified Biomimetic Architecture for Vascular Tissue Engineering Applications

Xie Chao,Guo Ting,Wang Wei,Li Gang,Cai Zhou,Chen Shen,Wang Xianwei,Liu Ziyu,Wang Zuyong 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.4

BACKGROUND: Vascular intimal hyperplasia (IH) is one of the key challenges in the clinical application of smalldiameter vascular grafts. Current tissue engineering strategies focus on vascularization and antithrombotics, yet few approaches have been developed to treat IH. Here, we designed a tissue-engineered vascular scaffold with portulaca flavonoid (PTF) composition and biomimetic architecture. METHOD: By electrospinning, PTF is integrated with biodegradable poly(e-caprolactone) (PCL) into a bionic vascular scaffold. The structure and functions of the scaffolds were evaluated based on material characterization and cellular biocompatibility. Human vascular smooth muscle cells (HVSMCs) were cultured on scaffolds for up to 14 days. RESULTS: The incorporation of PTF and preparation parameters during fabrication influences the morphology of the scaffold, including fibre diameter, structure, and orientation. Compared to the PCL scaffold, the scaffolds integrated with bioactive PTF show better hydrophilicity and degradability. HVSMCs seeded on the scaffold alongside the fibres exhibit fusiform-like shapes, indicating that the scaffold can provide contact guidance for cell morphology alterations. This study demonstrates that the PCL/PTF (9.1%) scaffold inhibits the excessive proliferation of HVSMCs without causing cytotoxicity. CONCLUSION: The study provides insights into the problem of restenosis caused by IH. This engineered vascular scaffold with complex function and preparation is expected to be applied as a substitute for small-diameter vascular grafts.

Tissue-engineered blood vessels with endothelial nitric oxide synthase activity

Lim, Sang Hyun,Cho, Seung-Woo,Park, Jong-Chul,Jeon, Oju,Lim, Jae Min,Kim, Sang-Soo,Kim, Byung-Soo Wiley Subscription Services, Inc., A Wiley Company 2008 Journal of Biomedical Materials Research Part B Vol. No.

<P>Nondegradable synthetic polymer vascular grafts used in cardiovascular surgery have shown serious shortcomings, including thrombosis, calcification, infection, and lack of growth potential. Tissue engineering of vascular grafts with autologous stem cells and biodegradable polymeric materials could solve these problems. The present study is aimed to develop a tissue-engineered vascular graft (TEVG) with functional endothelium using autologous bone marrow-derived cells (BMCs) and a hybrid biodegradable polymer scaffold. Hybrid biodegradable polymer scaffolds were fabricated from poly(lactide-co-ϵ-caprolactone) (PLCL) copolymer reinforced with poly(glycolic acid) (PGA) fibers. Canine bone marrow mononuclear cells were induced in vitro to differentiate into vascular smooth muscle cells and endothelial cells. TEVGs (internal diameter: 10 mm, length: 40 mm) were fabricated by seeding vascular cells differentiated from BMCs onto PGA/PLCL scaffolds and implanted into the abdominal aorta of bone marrow donor dogs (n = 7). Eight weeks after implantation of the TEVGs, the vascular grafts remained patent. Histological and immunohistochemical analyses of the vascular grafts retrieved at 8 weeks revealed the regeneration of endothelium and smooth muscle and the presence of collagen. Western blot analysis showed that endothelial nitric oxide synthase (eNOS) was expressed in TEVGs comparable to native abdominal aortas. This study demonstrates that vascular grafts with significant eNOS activity can be tissue-engineered with autologous BMCs and hybrid biodegradable polymer scaffolds. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008</P>

조직 공학을 위한 신생 혈관의 역할

김명주(Myeong Joo Kim),지병훈(Byung Hoon Chi),조민지(Min Ji Cho),황영미(Young Mi Whang),장인호(In Ho Chang) 대한비뇨기종양학회 2017 대한비뇨기종양학회지 Vol.15 No.2

Tissue engineering is limited by our inability to adequately vascularize tissues post implantation because all tissue-engineered substitutes (with the exception of cornea and cartilage) require a vascular network to provide the nutrient and oxygen supply needed for their survival. This review gives a brief overview of the processes and factors involved in the vascularization and angiogenesis and summarizes the different strategies to overcome the issue of slow vascularization and angiogenesis in a range of tissue-engineered substitutes. Moreover, we will announce some potential future plans.