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PubMed2006

[Long-term observation of large weight-bearing bone defect in goats repaired with tissue engineering technique].

OBJECTIVE: To observe the long-term effect of tissue engineering-based repair of large weight-bearing bone defect in goats, and the final outcome of the scaffold material coral hydroxyapatite (CHAP) in vivo. METHODS: Fifteen Chinese goats were subjected to operations to induce a 2-cm left tibial diaphyseal defect, which was filled subsequently with CHAP and bone marrow stromal stem cells (BMSCs). The repaired defects were evaluated by ECT, X-ray and histology in the early stage and at 6, 12, 18, and 24 months postoperatively. RESULTS: ECT showed good bone regeneration and revascularization within 2 months postoperatively. X-ray and histology displayed eccentric and gradual bone regeneration in the early stage, and the tissue-engineered bone graft was firmly healed with the goat tibia. X-ray and histological examination at 6, 12, 18, 24 months postoperatively revealed moulding of the new bones and medullary cavity recanalization, and the structure of CHAP disappeared and gradually integrated into the new bones. CONCLUSION: Tissue-engineered bone is capable of total repair of large bone defect in goats by forming normal functional new bones. CHAP can be eventually degraded completely and become the component of the newly generated bones.

Animals↗

PubMed2005

Anabolic actions of PTH (1-34): use of a novel tissue engineering model to investigate temporal effects on bone.

PTH is in clinical use for the treatment of osteoporosis and is under intensive investigation for its potential in applications of tissue engineering, fracture healing, and implant integration. However, the mechanisms of its action to stimulate bone formation are still unclear. A novel bone tissue engineering model was used to elucidate basic mechanisms of PTH anabolic actions. Ectopic ossicles containing cortical bone, trabecular bone, and a hematopoietic marrow were generated from implanted bone marrow stromal cells (BMSC). One week after implantation, nude mice were administered PTH or vehicle for 1 week (group 1), 3 weeks (group 2), or 7 weeks (group 3). Another group was also treated for 3 weeks, initiated 12 weeks after implantation (group 4). Micro-radiography and histomorphometry revealed increased marrow cellularity in group 1 PTH-treated ossicles, increased bone in group 2 PTH-treated ossicles, and similar amounts of bone in both group 3 and 4 ossicles regardless of treatment. Incidence of phosphate mineral and phosphate mineral to hydroxyproline ratio via Raman spectroscopy were significantly higher after 3 weeks versus 1 week of PTH treatment, but there was no difference between PTH- and vehicle-treated ossicles. Early events of PTH action in group 1 ossicles and the effects of a single injection of PTH on 1- and 2-week-old ossicles were evaluated by Northern blot analysis. Osteocalcin (OC) mRNA was increased after 1 week of intermittent PTH treatment in ossicles and calvaria but an acute injection did not alter OC mRNA. In contrast, a single injection of PTH increased matrix gamma-carboxyglutamic acid protein (MGP) mRNA in 2-week-old ossicles. Differential and temporal-dependent effects of PTH on OC and MGP suggest at the molecular level, that PTH acts to inhibit osteoblast mineralization. However, this does not translate into tissue level alterations. These data indicate that anabolic actions of PTH in ectopic ossicles are temporally dependent on the BMSC implanted and suggest that cell implantation strategies are particularly responsive to PTH.

Adipocytes↗

PubMed2001

Tissue engineering of cardiac valves on the basis of PGA/PLA Co-polymers.

The limitations of currently used heart valve devices are well known. For prosthetic valves they include infection risk and thrombembolic complications; biologic devices have limited durability. Particularly for pediatric cardiac patients the problem of a lack of growth potential remains a serious issue. The multidisciplinary field of tissue engineering potentially offers an attractive pathway to overcome these disadvantages. The basic concept of tissue engineering is to build a new "tissue" from individual cellular components in vitro using a scaffold to provide an architecture upon which the cells can organize and develop into the desired "tissue" prior to implantation. The scaffold provides the biomechanical profile for the replacement tissue until the cells produce their own extracellular matrix. This newly generated matrix would then ultimately provide the structural integrity and biomechanical profile for the newly developed tissue structure. This work focuses on the concept of using a synthetically produced co-polymer (polyglycolic acid/polylactid acid) as the scaffold for the development of a new generation of heart valves.

Biomechanical Phenomena↗

PubMed2002

Differential effects of growth factors on tissue-engineered cartilage.

The effects of four regulatory factors on tissue-engineered cartilage were examined with specific focus on the ability to increase construct growth rate and concentrations of glycosaminoglycans (GAG) and collagen, the major extracellular matrix (ECM) components. Bovine calf articular chondrocytes were seeded onto biodegradable polyglycolic acid (PGA) scaffolds and cultured in medium with or without supplemental insulin-like growth factor (IGF-I), interleukin-4 (IL-4), transforming growth factor-beta1 (TGF-beta1) or platelet-derived growth factor (PDGF). IGF-I, IL-4, and TGF-beta1 increased construct wet weights by 1.5-2.9-fold over 4 weeks of culture and increased amounts of cartilaginous ECM components. IGF-I (10-300 ng/mL) maintained wet weight fractions of GAG in constructs seeded at high cell density and increased by up to fivefold GAG fractions in constructs seeded at lower cell density. TGF-beta1 (30 ng/mL) increased wet weight fractions of total collagen by up to 1.4-fold while maintaining a high fraction of type II collagen (79 plus minus 11% of the total collagen). IL-4 (1-100 ng/mL) minimized the thickness of the GAG-depleted region at the construct surfaces. PDGF (1-100 ng/mL) decreased construct growth rate and ECM fractions. Different regulatory factors thus elicit significantly different chondrogenic responses and can be used to selectively control the growth rate and improve the composition of engineered cartilage.

Animals↗

PubMed2005

Application of tissue engineering techniques for rotator cuff regeneration using a chitosan-based hyaluronan hybrid fiber scaffold.

BACKGROUND: The current surgical procedures for irreparable rotator cuff tears have considerable limitations. Tissue engineering techniques using novel scaffold materials offer potential alternatives for managing these conditions. HYPOTHESIS: A chitosan-based hyaluronan hybrid scaffold could enhance type I collagen products with seeded fibroblasts and thereby increase the mechanical strength of regenerated tendon in vivo. STUDY DESIGN: Controlled laboratory study. METHODS: The scaffolds were created from chitosan-based hyaluronan hybrid polymer fibers. Forty-eight rabbit infraspinatus tendons and their humeral insertions were removed to create defects. Each defect was covered with a fibroblast-seeded scaffold (n = 16) or a non-fibroblast-seeded scaffold (n = 16). In the other 16 shoulders, the rotator cuff defect was left free as the control. At 4 and 12 weeks after surgery, the engineered tendons were assessed by histological, immunohistochemical (n = 2), and biomechanical (n = 6) analyses. RESULTS: Type I collagen was only seen in the fibroblast-seeded scaffold and increased in the regenerated tissue. The tensile strength and tangent modulus in the fibroblast-seeded scaffold were significantly improved from 4 to 12 weeks postoperatively. The fibroblast-seeded scaffold had a significantly greater tangent modulus than did the non-fibroblast-seeded scaffold and the control at 12 weeks. CONCLUSION: This scaffold material enhanced the production of type I collagen and led to improved mechanical strength in the regenerated tissues of the rotator cuff in vivo. CLINICAL RELEVANCE: Rotator cuff regeneration is feasible using this tissue engineering technique.

Animals↗

PubMedDate not supplied

[Mesenchymal stem cells for tissue engineering of bone: 3D-cultivation and osteogenic differentiation on mineralized collagen].

AIM: Due to their plasticity and high proliferation capacity in vitro, human mesenchymal stem cells (MSC) are promising candidates for substitution of mesenchymal tissues, such as bone. According to the tissue engineering concept, combinations of cells and three dimensional scaffolds are used to replace damaged tissue. Although various attempts have been made, the optimal combination of cells and artificial scaffold has not been found so far. METHODS: In this work, human MSC were isolated from bone marrow aspirates according to standard protocols and cultivated on mineralized collagen. Osteogenic differentiation was induced by medium containing dexamethasone, ascorbic acid and beta-glycerophosphate. Cell proliferation on the scaffold (WST-1 vitality assay, total protein measurement) and osteogenic differentiation (quantitative Real-Time-RT-PCR) were monitored for 24 days. RESULTS: Viable cells were found within the matrix throughout the cultivation period using histological and histochemical methods. Effective osteogenic differentiation could be demonstrated by the increase of expression of osteogenic marker genes (such as alkaline phosphatase) on a molecular level. CONCLUSION: Our results make the cell/matrix construct investigated in this work a promising candidate for tissue engineering of bone using mesenchymal stem cells. This has to be tested further by in vivo analysis.

Alkaline Phosphatase↗

PubMedDate not supplied

Tissue engineering of autologous cartilage grafts in three-dimensional in vitro macroaggregate culture system.

In the field of tissue engineering, techniques have been described to generate cartilage tissue with isolated chondrocytes and bioresorbable or nonbioresorbable biomaterials serving as three-dimensional cell carriers. In spite of successful cartilage engineering, problems of uneven degradation of biomaterial, and unforeseeable cell-biomaterial interactions remain. This study represents a novel technique to engineer cartilage by an in vitro macroaggregate culture system without the use of biomaterials. Human nasoseptal or auricular chondrocytes were enzymatically isolated and amplified in conventional monolayer culture before the cells were seeded into a cell culture insert with a track-etched membrane and cultured in vitro for 3 weeks. The new cartilage formed within the in vitro macroaggregates was analyzed by histology (toluidine blue, von Kossa-safranin O staining), and immunohistochemistry (collagen types I, II, V, VI, and X and elastin). The total glycosaminoglycan (GAG) content of native and engineered auricular as well as nasal cartilage was assayed colorimetrically in a safranin O assay. The biomechanical properties of engineered cartilage were determined by biphasic indentation assay. After 3 weeks of in vitro culture, nasoseptal and auricular chondrocytes synthesized new cartilage with the typical appearance of hyaline nasal cartilage and elastic auricular cartilage. Immunohistochemical staining of cartilage samples showed a characteristic pattern of staining for collagen antibodies that varied in location and intensity. In all samples, intense staining for cartilage-specific collagen types I, II, and X was observed. By the use of von Kossa-safranin O staining a few positive patches-a possible sign of beginning mineralization within the engineered cartilages-were detected. The unique pattern for nasoseptal cartilage is intense staining for type V collagen, whereas auricular cartilage is only weakly positive for collagen types V and VI. Engineered nasal and auricular macroaggregates were negative for anti-elastin antibody (interterritorially). The measurement of total GAG content demonstrated higher GAG content for reformed nasoseptal cartilage compared with elastic auricular cartilage. However, the total GAG content of engineered macroaggregates was lower than that of native cartilage. In spite of the mechanical stability of the auricular macroaggregates, there was no equilibrium of indentation. The histomorphological and immunohistochemical results demonstrate successful cartilage engineering without the use of biomaterials, and identify characteristics unique to hyaline as well as elastic cartilage. The GAG content of engineered cartilage was lower than in native cartilage and the biomechanical properties were not determinable by indentation assay. This study illustrates a novel in vitro macroaggregate culture system as a promising technique for tissue engineering of cartilage grafts. Further long-term in vitro and in vivo studies must be done before this method can be applied to reconstructive surgery of the nose or auricle.

Cartilage, Articular↗

PubMed2006

[A study on repairing mandibular defect by means of tissue-engineering and human bone morphogenetic protein-2 gene transfection in osteoporotic rats].

OBJECTIVE: To investigate the feasibility of repairing bone defect with methods of tissue-engineering and human bone morphogenetic protein-2 (hBMP-2) gene transfection in osteoporotic rats. METHODS: Twenty-four 6-month-old female Sprague-Dawley rats underwent ovariectomy, while 8 rats received sham-operations. Three months later, bone mesenchymal stem cells (BMSC) harvested from osteoporotic rats were divided into two groups randomly. Experimental group were transfected by recombinant plasmid carrying hBMP-2 gene, and control group left untreated. All BMSC were seeded into coralhydroxyapatite scaffolds. Then the cell/scaffold constructs were implanted into the defect site created in the ramus of mandible of osteoporotic rats respectively. RESULTS: Positive results were confirmed by immunohistochemistry and in situ hybridization in experimental group. New bone formation was found at the margin of the defect treated with the BMSC modified by hBMP-2 gene transfer at 4 weeks after implantation and appeared mature 8 weeks after the treatment. However, the amount of newly formed bone was much less and there was some adipose tissue at defect margins 8 weeks after implantation in control group. CONCLUSIONS: The results of this experiment indicate that BMSC-mediated rhBMP-2 gene therapy in conjunction with bone tissue engineering may allow for successful treatment of large bone defects in osteoporosis rats.

Animals↗

PubMedDate not supplied

Modeling aberrant wound healing using tissue-engineered skin constructs and multiphoton microscopy.

BACKGROUND: Keloids and hypertrophic scars result from aberrant wound healing and remain a potential complication of any surgical procedure or trauma. Investigation of aberrant wound healing has been limited to the study of growth factors, collagen precursors, and DNA synthesis in simple in vitro systems, which necessitate removal or destruction of cells or factors in the growth environment of cell cultures. Multiphoton microscopy (MPM) can use endogenous chromophores such as collagen and nicotinamide adenine dinucleotide hydrogenase to produce thin optical sections of thick living tissues without the use of dyes or stains. Endogenous second-harmonic-generation (SHG) signals in collagen can be collected to form an MPM image. OBJECTIVE: To present a novel wound-healing model used to investigate keloid-derived fibroblast activity and collagen production in the same intact tissue-engineered construct over time. METHODS: Artificial tissue constructs called RAFTs (produced by suspension of keloid or normal dermal fibroblasts in type I collagen gel with an overlying keratinocyte layer) were cultured at air-fluid interface. Multiphoton microscopy SHG images of collagen in the intact tissue constructs consisting of normal or keloid-derived fibroblasts were obtained. The constructs were then incised with a scalpel. Serial MPM and phase-contrast microscopy images were obtained to monitor changes in the extracellular matrix in response to wounding of the artificial skin construct over 8 days. RESULTS: The tissue-engineered constructs formed a bilayer resembling the dermis and epidermis of human skin. Phase-contrast microscopy revealed migration of keratinocytes into the defect created by scalpel wounding. The constructs were found to contract with time after wounding. The MPM SHG images showed collagen deposition in the tissue constructs after wounding. Tissue constructs with keloid-derived fibroblasts were found to deposit collagen at a higher rate than those with normal fibroblasts. CONCLUSIONS: The MPM model described herein permits serial observation of the same intact specimens without the need for fixation or cytotoxic stains. Furthermore, it demonstrates the biologic activity of RAFT artificial tissue constructs.

Cells, Cultured↗

PubMed2005

Regeneration of mastoid air cells in clinical applications by in situ tissue engineering.

OBJECTIVES: To regenerate of the mastoid air cells and their functions for the treatment of incurable otitis media. MATERIALS AND METHOD: In situ tissue-engineered mastoid air cells using three-dimensional hydroxy apatite (3D-HA) of honeycomb-like structure were used as artificial pneumatic bones. This 3D-HA is made of calcium phosphate and has a high ratio of micropores, 90%. Its surface is coated with collagen. Ten patients (4 males, 6 females) for this clinical study were randomly selected among the patients with severe cholesteatoma, adhesive otitis media, and purulent chronic otitis media, and they were to be received a staged operation. At the first stage of tympanoplasty, collagen-coated 3D-HA was put into the newly opened mastoid cavity, and it was fixed by fibrin glue. Recovery of mastoid aeration and regeneration of the pneumatic air cells of the mastoid cavity were estimated by images of high-resolution computed tomography (HRCT) after the first operation. At the second stage of operation, histopathologic examinations of specimens of HA taken from the reopened mastoid cavity were performed. RESULTS: Aerations in the mastoid cavity were observed in 9 of the 10 patients within 12 months after the second operation. Moreover, the pneumatic structure in the mastoid cavity was partially regenerated in five patients. In these successful cases, mucosa with newly formed capillaries was observed on the surface of the implanted HA at the second stage of operation. In the failure cases, however, connective tissues and granulations invaded the space of the 3D-HA. They were observed as soft-tissue density areas in the HRCT scan images. CONCLUSIONS: This study indicates that mucosa can grow on the surface of implanted artificial 3D-HA and can have a gas exchange function in the newly opened mastoid cavity. These tissue-engineered mastoid air cells may be a possible treatment for intractable otitis media.

Adult↗

PubMed2002

Preparation and biocompatibility of tissue-engineered scaffold materials based on collagen.

OBJECTIVE: To prepare a tissue-engineered scaffold material using collagen as the matrices and to study the blood compatibility and tissue biocompatibility of this material. METHODS: Physical, chemical and physical/chemical methods were used for the crosslinking of the collagen. RESULTS: Dynamic blood clotting tests indicated that the blood clotting index (BCI) of the crosslinked collagen materials prepared by different means decreased as their contact with the blood was prolonged, and the collagen material obtained after crosslink through 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide method showed the highest BCI after contact with the blood within certain length of time. Hemolysis ratios of all the crosslinked collagen materials were shown to be much lower than 5%, well conforming to the requirement of biomaterials. Scanning electron microscopy showed that the platelets attached to the surface of the crosslinked collagen materials, having a fairly small number, were not morphologically distorted. CONCLUSION: The collagen materials obtained by the 3 crosslink methods have good blood compatibility. The cells grow well on the surfaces of the materials, indicating their good biocompatibility.

Biocompatible Materials↗

PubMed2004

Protein-based tissue engineering in bone and cartilage repair.

Bioactive proteins signal host or transplanted cells to form the desired tissue type. Matrix systems are utilized to locally deliver the proteins and to maintain effective protein concentrations. For some indications, a matrix is required to define the physical form of the regenerated tissue. Substantial progress has been made in bone tissue engineering in recent years, based on the results of controlled clinical studies using bone morphogenetic proteins. Ongoing research in this area centers on the design of additional delivery matrices to expand the clinical indications, using synthetic delivery systems that mimic biological qualities of the natural materials currently in use. Although a similar rationale exists for the regeneration of articular cartilage with bioactive factors, advancement in this area has not been as substantial.

Animals↗

PubMed2001

Fetal tissue engineering: diaphragmatic replacement.

BACKGROUND/PURPOSE: Prosthetic repair of congenital diaphragmatic hernia has been associated with high complication rates. This study was aimed at applying fetal tissue engineering to diaphragmatic replacement. METHODS: Fetal lambs underwent harvest of skeletal muscle specimens. Once expanded in vitro, fetal myoblasts were suspended in a collagen hydrogel submitted to controlled radial tension. The construct was then placed in a bioreactor. After birth, all animals underwent creation of 2 diaphragmatic defects. One defect was repaired with the autologous-engineered construct placed in between 2 acellular supporting membranes and the other with an identical construct but without any cells. Each animal was its own control (graft, n = 10). Animals were killed at different time-points postimplantation for histologic examination. Statistical analysis was by analysis of variance (ANOVA). RESULTS: Fetal myoblasts expanded up to twice as fast as neonatal cells. Hydrogel-based radial tension enhanced construct architecture by eliciting cell organization within the scaffold. No eventration was present in 4 of 5 engineered constructs but in 0 of 5 acellular grafts (P<.05). At harvest, engineered constructs were thick and histologically resembled normal skeletal muscle, whereas acellular grafts were thin, floppy, and showed low cell density with increased fibrosis. CONCLUSIONS: Unlike acellular grafts, engineered cellular diaphragmatic constructs are anatomically and histologically similar to normal muscle. Fetal tissue engineering may be a viable alternative for diaphragmatic replacement.

Analysis of Variance↗

PubMed2002

Modulating diseased skin with tissue engineering: actinic purpura treated with Apligraf.

BACKGROUND: Actinic purpura (AP) is an important medical issue and quality of life issue in the elderly. Current treatment of AP is limited to prevention of cutaneous aging. OBJECTIVE: To assess the utility of tissue engineered skin (Apligraf, Organogenesis, Canton, MA) as a tissue modulator in diseased skin and as treatment for AP. METHODS: A thin partial-thickness section of AP was removed from the forearm of an elderly gentleman and replaced with fenestrated Apligraf. Healing, durability and cosmetic outcome were assessed. RESULTS: Apligraf-treated skin healed rapidly with good clinical "take." Lack of new skin tears and resultant erosions or ulcer formation suggests improved durability of the Apligraf-treated area occurred. CONCLUSION: These results suggest that tissue engineered skin modulates aged dermal tissue to behave in a more sturdy fashion. Furthermore, in selected cases Apligraf may represent a treatment option for AP.

Aged↗

PubMed2001

Development of a three-dimensional transmigration assay for testing cell--polymer interactions for tissue engineering applications.

The ability of synthetic or natural scaffolds to support invasion of cells from surrounding tissue is a key parameter for tissue engineering (TE). In this study, the migration of fibroblasts, chondrocytes, and osteoblasts into biodegradable polymer scaffolds was evaluated using a novel, three-dimensional (3-D) transmigration assay. This assay is based on a cell-populated contracted collagen lattice with a biodegradable polymer scaffold implanted at the center of the collagen gel. Cell migration into the scaffolds was assessed both quantitatively and qualitatively following various time lengths in culture using image analysis. Chondrocytes, incorporated within the collagen lattice, migrated into polymer scaffolds, when cultured both statically or in a rotating bioreactor. However, the bioreactor cultures resulted in a significantly greater cell invasion as compared to static cultures. There was a cell density-dependent osteoblast migration from collagen lattice into polymer scaffold, when tested in the transmigration assay. In addition, polymer scaffolds, treated with or without recombinant human platelet-derived growth factor (rh-PDGF-BB) were evaluated for fibroblast migration. The presence of rh-PDGF-BB resulted in significantly greater fibroblast invasion as compared to untreated scaffolds. Our studies suggest that the transmigration model provides a rapid system for testing cell invasion of potential scaffolds for tissue engineering applications.

Becaplermin↗

PubMedDate not supplied

Construction of tissue-engineered homograft bioprosthetic heart valves in vitro.

Human mesenchymal stem cells (MSCs) differentiate into multiple cell-lineages and may serve as an alternative source of seed cells for tissue engineering. We investigated whether MSCs could be induced to differentiate into endothelial cells (ECs) and function as seed cells for the in vitro construction of tissue-engineered heart valves (TEHVs). Aortic or pulmonary valve homografts were decellularized with 0.1% sodium dodecylsulphate and used as scaffolds for TEHVs. The MSCs were isolated from human bone marrow by Percoll gradient centrifugation (1.073 g/ml), differentiated into ECs with vascular endothelial growth factor (10 ng/ml), and seeded onto a decellularized scaffold (high-density seeding, >10(5) cells/cm2) and grown in static culture for 14 days. Over 90% of the differentiated cells from MSCs stained positively for von Willebrand factor and Tie-2-related antigen. Additionally, Weibel-Palade corpuscle was observed in the cytoplasm of these cells. Levels of reendothelialization in static culture on days 7, 14, and 20, were 73%, 85%, and 95%, respectively. These results show that MSCs from human bone marrow can differentiate, in vitro, into ECs that can then be used to construct TEHVs. Reendothelialization in static culture can be used to provide the basic material for pulsatile-flow cultivation.

Adult↗

PubMed2003

Tissue-engineered stomach: a preliminary report of a versatile in vivo model with therapeutic potential.

BACKGROUND/PURPOSE: Microgastria and postgastrectomy morbidities are substantial. The authors hypothesized a functional living tissue-engineered stomach could function as a replacement alternative. METHODS: Stomach organoid units, mesenchymal cores surrounded by epithelia, were isolated from neonatal and adult rats and transplanted paratopically on biodegradable polymer tubes, which were implanted in syngeneic hosts, varying the inclusion of stomach regions. Four weeks later, tissue-engineered stomach (TES) was either harvested or anastomosed. GFP labeling was performed before implantation. Histology and immunohistochemical detection of the antigensgastrin and actin smooth muscle were performed. RESULTS: Ninety-eight percent of all animals generated TES, including TES formation from adult tissue. Immunohistochemistry for alpha-actin smooth muscle and gastrin confirms the presence of a smooth muscle layer and a well-developed gastric epithelium containing all the elements of the native rat stomach including gastric pits and squamous layers, varying by included regions at harvest. TES architecture was maintained in anastomosis: GFP-labeled TES maintained signal in anastomosis, proving the donor origin of the TES. CONCLUSIONS: TES resembles native stomach and maintains robust histology in anastomosis, a new versatile model for the study of gastric physiology and possible therapy.

Actins↗

PubMed2006

'UroMaix' scaffolds: novel collagen matrices for application in tissue engineering of the urinary tract.

Reconstruction of bladder and ureter tissue is indicated in cases of injury, stenosis, infection or tumor. Substitution by ileum, colon or pure synthetic polymers generates a variety of complications. Biohybrid tissue mimicking structural and functional attributes of the multilayered wall architecture of the urinary conduit may be the solution to current problems. This study reports on porcine urinary tract cells isolated and placed on UroMaix matrices with different degrees of cross-linking produced from highly purified type I collagen from medically approved porcine tissue. A patented procedure revealed membrane structures composed of a dense fibrous side and an open fibrous side. These scaffolds with the porcine urinary tract cells were incubated in a batch culture system for up to 14 days. Cell growth and topographical orientation were examined. Urothelial cells showed maximum attachment and a significant increase of living cells on the dense fiber layer of UroMaix-1. No attachment of urothelial cells occurred on the other prototypes. Smooth muscle cells showed similar behavior within the open fiber layer of all UroMaix matrices. Both urothelial and smooth muscle cells retained their phenotypes as demonstrated by the immunostaining of epithelial cytokeratin 18 and the smooth muscle myosin heavy chain respectively. Thus we could show that UroMaix scaffolds support the attachment and proliferation of urinary tract cells. The elastomeric properties of the collagenous matrices promise attractive applications in the tissue engineering of the urinary tract with its high mechanical demands.

Animals↗