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Results for “Bioartificial Organs”

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At least 289 records · Page 16Linked to original sources
PubMed2000

Tissue-engineered heart valve leaflets: an effective method for seeding autologous cells on scaffolds.

BACKGROUND: A precondition for the successful formation of tissue-engineered heart valves is the generation of a proper matrix on biodegradable scaffolds over a limited period of time. The aim of this study was to find an effective method of seeding autologous cells on these scaffolds to create a new matrix for heart valves. METHODS: Myofibroblasts and endothelial cells were isolated and cultured from an ovine artery. A synthetic biodegradable scaffold consisting of polyglycolic and polylactic acids was seeded first with the myofibroblasts, then coated with endothelial cells. Three different methods of myofibroblast seeding were compared: I) daily seeding of myofibroblasts (1x10(6)) for ten days and culture for four days; II) seeding of myofibroblasts (1x10(7)) and culture for 14 days with the use of a simple medium; III) seeding of myofibroblasts (1x10(7)) with the use of a medium containing collagen and culture for 14 days. Light and electron microscopic analyses were performed. RESULTS: The group that used the medium containing collagen showed the best results in terms of seeding efficiency. CONCLUSION: Seeding autologous cells with a medium containing collagen onto the scaffold showed the largest cell population and might generate the best matrix on the scaffold.

Absorbable Implants↗
PubMed2000

A study of injectable tissue-engineered autologous cartilage.

OBJECTIVE: To test the effectiveness of the new techniques of tissue-engineered cartilage. METHODS: Chondrocytes were harvested through type II collagenase digestion from the auricle of New Zealand rabbits. The cells were mixed with alginate to generate chondrocytes/alginate composites with final cellular density of 50 x 10(6) per mL. Calcium chloride was used as the cross-linking agent to gel the aqueous alginate solution. The chondrocytes/alginate composites were injected into the dorsal subcutaneous tissue of New Zealand rabbits through autologous cells grafts. The specimens were observed during cartilage formation at 4, 8, and 12 weeks after injection. RESULTS: Prior to harvesting, chondrocytes/alginate composites were easily visualized under the dorsal skin of animals. The appearance of experimental specimens was similar to that of native cartilage in gross morphology. Using a standard hematoxylin and eosin stain, the histologic features of all experimental specimens demonstrated new cartilage formation. With a Masson's trichrome and safranin O stain, the presence of collagen and glycosaminoglycan (GAG) was observed at 8 and 12 weeks. CONCLUSION: This study demonstrated that polymerization of alginate hydrogel can be controlled to allow injection of chondrocytes that produce new autologous cartilage at subcutaneous dorsal site of rabbits. Injectable tissue-engineered autologous cartilage is promising for potential use in oral and maxillofacial surgery.

Alginates↗
PubMed2002

[Progress in studies of tissue-engineered heart valves].

Valve replacement represents the most common surgical therapy for valvular heart diseases. However, the long-term results of the valve protheses in clinical use are not satisfying. Recently, with the development of tissue engineering, more and more studies are focusing on creating ideal valve substitutes through seeding autologous cells on biodegradable scaffold. This article describes the definition of valvular tissue engineering, the choice of scaffold biomaterials, the methods of cell culture and seeding, and the evaluation of tissue-engineered heart valves. Furthermore, the problems which should be resolved in the future are also presented in the article.

Animals↗
PubMed2002

[Application of tissue engineering in bioartificial renal tubule].

Tissue engineering is a discipline involving both materials science, engineering and life science. It has found successful application in Bioartificial renal tubule assist device RAD which is still under development. Experiments have proved that RAD can serve as renal tubule to perform its transport, metabolic and endocrine functions in patients with acute or chronic renal failure.

Animals↗
PubMed2002

Autologous satellite cell seeding improves in vivo biocompatibility of homologous muscle acellular matrix implants.

Acellular matrix obtained from homologous muscular tissue has been previously used to repair muscular defects. However, the implants, although not rejected, give rise to an intense inflammatory response and are rapidly replaced by fibrous tissue. In this study we examined the possibility that co-culture with autologous satellite cells can improve the efficiency of homologous acellular matrix as skeletal muscle substitute. Satellite cells, isolated from rat dorsal muscle, were cultured in vitro on homologous acellular matrix obtained by detergent-enzymatic treatment of abdominal muscle fragments. Scanning electron microscopy revealed that after 24 h of co-culture satellite cells were attached to the matrix, but still possessed a round shape. After 96 h, seeded cells began to flatten and to differentiate, originating few multinucleated myotubes. Patches of homologous matrix, seeded or not with autologous satellite cells, were implanted in the dorsal muscle of rats. At autopsy, the implants were recovered and processed for light microscopy. Two weeks after surgery, fibrous tissue started to replace the grafts composed only by acellular matrix, which at the 4th week were transformed into a fibrous scar. In contrast, at both times post-surgery the structure of implants containing autologous satellite cells was well preserved. The inflammatory reaction was modest and fibrosis was confined to the periphery of the grafts. It is concluded that the presence of autologous satellite cells is an important factor to preserve the structural integrity and to improve in vivo biocompatibility of homologous muscular acellular matrix implants.

Animals↗
PubMed2000

[Artificial skin cultured in vitro].

Artificial skin is a kind of skin which by using tissue engineering techniques, a skin-like material was formed by seeding epithelium cells and dermis fibroblasts on a good biocompatible material after proliferation. The trauma restoration and reconstruction were achieved by transplanting the skin graft an skin defects after the artificial skin graft cultured in vitro. Artificial skin research is a new active field in tissue engineering. It has wonderful prospect for clinics to radically settle the problem of restoration of skin defects. The recent studies on the models, cultured methods and influenced factors for epithium culture, dermis culture and artificial skin in vitro were reviewed in this paper.

Bioartificial Organs↗
PubMed2004

[Study on the interface of human hepatocyte/micropore polypropylene ultrafiltration membrane].

OBJECTIVE: To found a new interface of human hepatocyte/micropore polypropylene ultrafiltration membrane (MPP) with good cytocompatibility so as to construct bioartificial bioreactor with polypropylene hollow fibers in future. METHODS: MPP ultrafiltration membrane underwent chemical grafting modification through ultraviolet irradiation and Fe(2+) reduction. The contact angles of MPP and the modified MPP membranes were measured. Human hepatic cells L-02 were cultured. MPP and modified MPP membranes were spread on the wells of culture plate and human hepatic cells and cytodex 3 were inoculated on them. Different kinds of microscopy were used to observe the morphology of these cells. RESULTS: The water contact angle of MPP and the modified MPP membranes decreased from 78 degrees +/- 5 degrees to 27 degrees +/- 4 degrees (P < 0.05), which indicated that the hydrophilicity of the membrane was improved obviously after the grafting modification. Human hepatocyte L-02 did not adhere to and spread on the modified MPP membrane surface, and only grew on the microcarrier cytodex 3 with higher density and higher proliferation ratio measured by MTT. CONCLUSION: Grafting modification of acrylamide on MPP membrane is a good method to improve the human hepatocyte cytocompatibility with MPP ultrafiltration membrane.

Bioartificial Organs↗
PubMed2004

[Bio-artificial implants in orthopedics].

Aging of the population and thus of loadbearing cartilage produces a number of degenerative symptoms. At the knee, considerable macroscopic asymmetry of the joint underlies these degenerative changes, were it not for two menisci that somewhat neutralize this discongruency. Microscopically, cartilage is a structure within the knee joint that allows for low friction and congruent movement. Repetitive microtrauma rather than macrotrauma can affect its integrity. Both microscopically and macroscopically reconstruction of a cartilage-like structure is achieved through implantation of cultured cells or auto- and allografts either by minimally invasive or classical surgery, which theoretically could have a beneficial effect on the natural course of degeneration.

Aged↗
PubMed2005

Bio-artificial periosteum for severe open fracture--an experimental study of osteogenic cell/collagen sponge composite as a bio-artificial periosteum.

In an attempt to reduce complications in cases of severe open fracture, we developed a bio-artificial periosteum composed of osteogenic cells and collagen sponge. In the present study, we evaluated the osteogenic potential of the bio-artificial periosteum in vivo and in vitro. After 4-week incubation in vitro, the bio-artificial periosteum had high alkaline phosphatase activity and osteocalcin content. Moreover, energy dispersive X-ray analysis revealed numerous crystal structures consisting of P and Ca on the surface of the bio-artificial periosteum. Using a rat model for severe bone injury, we examined the bone formation process in defect sites covered with the bio-artificial periosteum. New bone formation occurred in the central part of the bone defect as well as at the bone edge. We conclude that by using the bio-artificial periosteum, the fracture site benefited from an improved osteogenic environment. These results indicate that a clinical trial to further evaluate this technique should be conducted.

Alkaline Phosphatase↗