Endothelialisierung von 6-mm-Gefassprothesen mit mikrovaskularen Endothelzellen aus dem Fettgewebe des Omentums. [Endothelialization of 6 mm vascular prostheses with microvascular endothelial cells from fatty tissue of the omentum]

The seeding of 6 mm Dacron prostheses with microvascular endothelial cells from omental adipose tissue leads to endothelialized prostheses, 5 weeks later with a complete coverage of functional and thrombus free endothelium. The method is ready for clinical trials

Einfluss der hamodynamischen Bedingungen und der Prothesenstruktur auf die Endothelialisierung von klinischen und experimentellen kleinlumigen Gefassprothesen [Effect of hemodynamic conditions and prosthesis structure on endothelialization of clinical and experimental small lumen vascular prostheses]

Seeding of small-diameter vascular prostheses (ID less than or equal to 6 mm) with autologous microvascular cells (AMVC) results in a complete endothelial cell layer on the luminal surface. The purpose of this study was to examine the influence of the blood flow velocity (due to 4 or 6 mm ID) and the structure of inner graft surface (crimped, uncrimped) on the endothelialization. AMVC were harvested from omental adipose tissue (mean: 0.56 X 10(6) cells/g tissue) from 10 mongrel dogs (mean: 27.9 kg). During preclotting, the 4 mm uncrimped and the 6 mm crimped double velour Dacron prostheses (Meadox Medicals, Inc.) were seeded with 1.0 X 10(6) cells/cm2 graft surface. Grafts were implanted into the carotid arteries (N = 5 in each group). The animals received antiplatelet therapy. After five weeks, all seeded prostheses were patent. The thrombus free surface (TFS) of seeded prostheses was 99.9% (4 mm) and 90.5% (6 mm). Scanning electron microscopy revealed an athrombogenic layer of endothelial cells on a smooth surface. -It is concluded that in canine experiments endothelialization of 4 and 6 mm grafts after seeding with AMVC is not affected by blood flow velocity or graft structure

Late neutrophil infiltration of canine endothelial cell seeded Dacron grafts

Neutrophil infiltration is known to affect the endothelial monolayer of seeded vascular grafts. The aim of this study was to develop an in vitro system allowing the monitoring of neutrophil (PMN) adherence after graft implantation. Dacron prostheses were seeded with autologous canine microvascular cells from omental adipose tissue and implanted for 35 days. In vitro, mature monolayers of canine homologous venous endothelial cells (CHVENC) were exposed to heparinized whole blood samples taken at days one and four postoperatively, followed by weekly tests. PMNs adherent to the CHVENC were counted per culture area. Results showed the feasibility of PMN monitoring, and demonstrated a late PMN adhesion, reaching its maximum about 20 days after implantation and decreasing to normal values after five weeks. It is concluded that in vitro tests can be used for noninvasive studies of host plasma factors and leukocyte activation

Long-term results of tissue development and cell differentiation on Dacron prostheses seeded with microvascular cells in dogs

PURPOSE: The purpose of this study was to investigate in vivo the long-term development, differentiation, and proliferation of the subendothelial tissue on Dacron prostheses seeded with microvascular cells (MVC). METHODS: Autologous MVC from omental adipose tissue were seeded on 4 mm Dacron prostheses and the prostheses interposed in the carotid arteries of mongrel dogs for 5, 13, and 26 weeks. RESULTS: Light and electron microscopic evaluation of patent seeded prostheses demonstrated an almost complete monolayer of endothelial cells and well-organized subendothelial tissue, whereas patent control prostheses were mainly covered by red and white thrombi, which were partially replaced by organized tissue with increased implantation time. The measurements of the thickness of the luminal cell layer in seeded and control grafts showed no statistically significant increase between 5 and 26 weeks of implantation. The subendothelial tissue of seeded prostheses demonstrated a time-dependent maturation of highly synthesizing myofibroblasts embedded in a collagen matrix to cells with features of smooth muscle cells located in a collagen-elastin matrix. In control grafts examined after 26 weeks the spontaneous endothelialization was accompanied by a delayed or incomplete maturation of subendothelial tissue. CONCLUSIONS: Our study indicates that MVC seeded onto Dacron prostheses are able to generate a vascular wall that does not continue to proliferate after prolonged implantation and that increasingly resembles the wall of a normal artery in cell differentiation and intercellular matrix