Biocompatibility of porous polyethylene implants tissue-engineered by extracellular matrix and VEGF.

Rapid ingrowth of blood vessels and low inflammatory response are considered major prerequisites for successful implantation of biomaterials in reconstructive surgery. Aim of the present study was to evaluate whether tissue-engineered porous polyethylene (PPE) implants providing extracellular matrix components (ECM) and vascular endothelial growth factor (VEGF) in vivo improve microvascular ingrowth and mechanical integration with regard to initial inflammatory responses. PPE implants (3 x 3 x 0.

Mosaicplasty with photooxidized, mushroom shaped, bovine, osteochondral xenografts in experimental sheep.

The goal was to study the performance of mushroom shaped, photooxidized, osteochondral grafts in mosaicplasty focusing on graft stability and survival. Mushroom shaped, photooxidized grafts (6 mm for the cartilaginous head of the mushroom, 3 mm for the stem) were implanted in the medial femoral condyle of 10 sheep. Four transplants were inserted per condyle in an overlapping fashion using the pressfit technique (n=40 grafts in 10 condyles).

The use of photooxidized, mushroom-structured osteochondral grafts for cartilage resurfacing--a comparison to photooxidized cylindrical grafts in an experimental study in sheep.

Objective: This article addresses the problem of structural design with osteochondral grafts used for cartilage resurfacing.

Methods: Photooxidized cylindrical or mushroom-shaped grafts were surgically implanted in the weight bearing area of the medial and lateral femoral condyles of eight sheep (condyles: N=8/group). Both types of photooxidized grafts contained no viable chondrocytes at the time of implantation.

Changes in subchondral bone in cartilage resurfacing--an experimental study in sheep using different types of osteochondral grafts.

Objective: This article addresses the subchondral bone integrity in cartilage resurfacing by comparing fresh, untreated auto-, xeno-, and photooxidized osteochondral allo- and xenografts. Photooxidation was expected to improve mechanical stability of the osteochondral grafts through an improved linkage of the collagen fibers within the bone matrix.

Design: Untreated auto- and xenografts and with photooxidation pretreated allo- and xenografts were surgically implanted in femoral condyles of sheep (n=40).

Tissue engineering in space.

The purpose of this paper is to present the status of that part of the [Microgravity Application Program] project related to the study of cartilage formation from pig chondrocytes. The work carried out so far followed two lines: (i) chondrocytes were incubated for up to three weeks in the RPM; (ii) a module developed for in-vitro cartilage formation will be tested in a sounding rocket flight (MASER 9, November 2001).

In vitro studies of a photo-oxidized bovine articular cartilage.

Bovine articular cartilage was photo-oxidized and cultured with native articular bovine cartilage and synovial membrane to study the interaction between these tissues mimicking the physiological situation in the joint. The photo-oxidation was applied as a pretreatment of cartilage for future use in cartilage resurfacing procedures in joints. Properties of the transplant were assessed by testing the production of local mediators, such as nitric oxide (NO) and prostaglandin E2 (PGE2), and neutral metalloproteinase activities under normal conditions and after stimulation with various stimulants representative of inflammatory changes in pathophysiological conditions.

Long term in-vivo studies of a photo-oxidized bovine osteochondral transplant in sheep.

Background: Articular cartilage has limited capacity to repair. Defects greater than 3 mm heal with formation of inferior fibrous cartilage. Therefore, many attempts have been made to find the ideal graft for larger cartilage lesions.

[Long-term results in the dog carotid artery with small lumen vascular prostheses with microvascular endothelial cells].

In this study we evaluated the long-term results of microvascular endothelial cell seeding of small diameter Dacron grafts with omentally derived cells in a canine model. 6 cm long and 4 mm I.D.

[Development of a small-lumen vascular prosthesis coated with autologous endothelial cells].

A new compliant prosthesis with a monolayer of autologous endothelial cells (ENC) has been developed. It consists of a porous polyurethane-siloxane-copolymer reinforced by a polyester network to prevent excessive dilatation. On the inner surface an ENC monolayer is established before implantation by a cell culture procedure.

A compliant small-diameter vascular prosthesis lined with functional venous endothelial cells.

The long-term patency of small-diameter vascular grafts is still unsatisfactory. In contrast to native arteries, they are inelastic and lack active antithrombogenicity. To improve long-term patency, a new 4 mm internal diameter prosthesis was developed which is compliant and lined with functional endothelial cells (ENC).

Development of small-diameter vascular prostheses covered with human endothelial cells: Possibilities and limits of in vitro-tests.

There is an increasing demand for small-diameter vascular prostheses for the replacement of arteriosclerotic coronary arteries. They may be replaced by autologous blood vessels, usually parts of the saphenous vein. Prostheses of synthetic materials and an inner diameter of less than 4 to 6 mm are unsatisfactory and, therefore, not implanted for coronary arteries.