In vitro association of type III collagen with elastin and with its solubilized peptides.

Elastin fibres or elastin solubilized peptides associated with type III collagen, under physiological conditions, to form a gel-like substance. The gel cohesion could be markedly improved either by desiccation process (gently air-dried rather than lyophilized) or by addition of adhesive connective proteins such as fibronectin, laminin and type IV collagen. They conferred to the material the composition and the structural appearance of typical basement membrane-like structure. Their properties enable us to investigate the biomaterial in several domains.

Elastin-derived protein coating onto poly(ethylene terephthalate). Technical, microstructural and biological studies.

Recently, it has been shown in our laboratory that certain proteins solubilized from elastin (ESP) formed a tight association with certain polymers such as elastin or polyethylene glycol terephthalate (PET) ... . The present paper deals with the description of the optimal chemical conditions of this unexpected association, its microstructure and its biological properties. A microstructural study of the composite ESP-PET material was performed using scanning and transmission electron microscopy. The thickness of the yield composite was evaluated (0.4-2 microm) but its imperviousness was unsatisfactory using ESP alone. So, we tentatively coated PET with the elastin-ESP complex. The microscopic views confirmed that the polymer was better filled by the organic matrix, the thickness of the layer being markedly improved (3 microm). Simultaneously, we attempted to verify whether the yielded composite retains the biological properties previously demonstrated with the 'Biopatches' and probably due to ESP. Thus, the culture of endothelial cells on an ESP-coating (with elastin or not) showed that a 100 microg/cm2 ESP concentration was able to promote endothelial cell growth in perfect conditions, maintaining their phenotypic character. While several physico-chemical determinations are in progress in our laboratory to identify and characterize the protein involved, a prototype of small-calibre vascular prosthesis was elaborated with elastin-ESP-PET composite and will be placed in a dog at the abdominal femoral junction to evaluate the in vivo performance of such an attractive material in artery restoration.

Colonization of a calcium phosphate/elastin-solubilized peptide-collagen composite material by human osteoblasts.

The evaluation of the suitability of a new biomaterial as a possible substitute for bone tissue is described here. This biomaterial is based on calcium phosphate particles linked to an artificial connective matrix, the elastin-solubilized peptides (ESP) associated with type I and III collagens. This work demonstrates the feasibility of shaping this composite material into discs, describes its microstructural characteristics, and evaluates its capacity as a substrate for the proliferation of human osteoblasts without loss of their phenotypic expression.

In vitro studies of elastin-fibrin biomaterial degradation: preservative effects of protease inhibitors and antibiotics.

The degradability of a new elastin-fibrin material was tested in vitro versus human pancreatic elastase (HPE) and plasmin (PL) activities. It is shown that aprotinine Iniprol, a well-known protease inhibitor and Eglin C, a new potent inhibitor of HPE, especially when used in synergy, efficiently protected the material. A small amount of specific antibiotics was incorporated into the material. The two products will allow the material to be used in digestive surgery with improved safety.

New preparation and microstructure of the EndoPatch elastin-collagen containing glycosaminoglycans.

Several improvements of the basic reaction between elastin-solubilized peptides and type I + III collagens are presented. They concern the prior incubation of the proteins in an adequate medium as well as the addition of heparan sulphate or hyaluronic acid (HA) and the consequent effects on the physical properties of yielded matrices. The addition of HA in small amounts enabled us to make membranes with good performances.

Use of a biodegradable elastin-fibrin material, Neuroplast, as a dural substitute.

Since the new Neuroplast biomaterial is now commonly used in several domains of restorative and curative surgery, its preliminary evaluation as a dura mater substitute in the rabbit was performed and is described herein. Whereas the importance of prosthesis thickness was implicated and solved (0.2 rather than 1.0 mm), both macroscopic examination and histological studies revealed for the neotissue an effective patency, a good continuity and especially no or almost no adherence at all. As Neuroplast is now available for use everywhere in humans, this material is being developed in several fields of neurosurgery.

New bioactivation mode for vascular prostheses made of Dacron polyester.

The performance of vascular prostheses, especially those of small calibre, still presents several problems. The use of polyesters such as the well-known poly(ethylene terephthalate) (Dacron) and, more recently, poly(tetrafluoroethylene) and polyurethanes provides a marked improvement. We have developed a process to increase the efficiency of such prostheses, using the ability of the Dacron polyester to be covalently modified by proteins under mild chemical conditions. The biomaterial is obtained from the particular interaction of elastin-solubilized peptides with type I + III collagens under very precise conditions. We have obtained an irreversible covalent bonding on Dacron. These biological conditions and the addition of connective proteins and glycosaminoglycans conferred on the resulting material a composition and a three-dimensional structure equivalent to the subendothelium, providing bioactive properties suitable for the development of a vascular prosthesis.

New artificial connective matrix made of fibrin monomers, elastin peptides and type I + III collagens: structural study, biocompatibility and use as tympanic membranes in rabbit.

Experiments leading to the conception and development of a new artificial connective matrix based on collagen-elastin-fibrin associations are presented. Preliminary evaluation of this biomaterial as an artificial tympanic membrane is described. Morphological evaluation was performed by histopathological and scanning electron microscopic studies. Biocompatibility was documented by subcutaneous implantation and experimental grafting in rabbits was performed with histopathological studies of the tympanic grafted membranes. The positive results obtained in this experimental study enable future studies in humans to be prepared.

Some factors affecting properties of elastin-fibrin biomaterial.

The elasticity, mechanical strength and permeability of a new biomaterial made of elastin and fibrin were investigated. It was shown that gamma-irradiation to sterilize the product, and sulphur derivatives (Merceptyl, thiourea, cystein) working as reticulating agents modified these properties. Depending on whether or not the biomaterial needs to be stiff, strong or elastic both physical processes could intervene separately or together. The good permeability of this material allows it to be used in several surgical fields as a true artificial connective matrix.

New artificial connective matrix-like structure made of elastin solubilized peptides and collagens: elaboration, biochemical and structural properties.

Several improvements of the basic reaction between elastin peptides and type III collagen, specially the addition of heparan sulphate proteoglycans, are presented. The consequent elaboration of either cell culture support or membranes are described and illustrated by scanning electron microscopy. The material produced possesses composition, very well organized lamellar structure and some properties quite close to natural membranes such as subendothelial tissue.

New artificial connective matrix-like structure: thrombogenicity and use as endothelial cell culture support.

The recently described artificial connective matrix made of elastin solubilized peptides, type I+III collagens and connective proteins is shown to have structural and biological properties very close to the natural arterial subendothelium: the capacity to promote endothelial cell cultures maintaining their phenotype expression and its non-thrombogenicity. This new bioactive composite material could be used to replace arteries.

Biocompatibility of elastin-fibrin material in the rat.

Biocompatibility and biodegradability of a new elastin-fibrin material were investigated in several organs and tissues of the rat. It has been demonstrated that the material was quite well tolerated in all cases, except in bone marrow. Its use is considered in several aspects of reparative or constructive surgery.

Unexpected original property of elastin derived proteins: spontaneous tight coupling with natural and synthetic polymers.

Elastin fibres can be decomposed into their constituting proteins using several processes; in particular by saponification of some bonds with KOH in aqueous tertiobutyl alcohol, elastin solubilized proteins - ESP- of 10 to 200 KDa were produced with a good yield (70-80%). It is demonstrated that some of these proteins were capable of tightly re-associating with the native elastin fibres and remained bound on the fibres, in spite of several drastic washes using 1 M Guanidinium, HCl at 37 degrees C for 1 h. At pH 4-5, approximately 30-40 microg ESP were retained per mg elastin. The same association is also shown to occur, under similar conditions, with Poly-ethylene-terephthalate, Poly-hexamethylene diamine-adipic acid but not with polyurethanes. The optimal conditions of the coupling were described as depending on ESP concentration, time, pH, ionic strength and Ca++. It was also shown that opposite pH conditions, i.e. pH 14, 0.5 M NaOH, could allow the retained proteins to desorb from polyesters. Hence, it will be possible to determine the sort of proteins which could be involved. This property of ESP allows us (1) to better understand the exceptional capacity of tissue repair certainly due to adhesive properties of the artificial connective matrices containing elastin or ESP, developed in our laboratory, (2) to provide a new approach for elucidating elastin microstructure and function, (3) especially to provide a new mode for coating certain fibres, yielding materials with bioactive and biofunctional qualities.

Evaluation of bioabsorbable elastin-fibrin matrix as a barrier in surgical periodontal treatment.

The purpose of this investigation was to test clinically the efficiency of a recently described bioabsorbable matrix as a guided tissue regeneration membrane. This matrix was prepared from an original reaction between elastin and fibrin monomers and is now extensively used in several domains of surgery. The study group was composed of 26 patients, with a total of 35 lesions (22 intrabony defects, 8 Class II furcations and 5 Class III furcations) presenting moderate to advanced adult periodontitis. After initial therapy, measurements were made with a calibrated periodontal probe. Probing depth (PD) and gingival margin location (GM) measurements were taken twice: immediately before surgery and after 6 months before re-entry. Clinical attachment level (CAL), vertical osseous level (VOL) and alveolar crest location (AC) measurements were taken during surgery and after 6 months with re-entry procedures for all the patients. Color change of the gingival margin was only observed in 4 defects and device exposure occurred in the proportion of 2 out of the 35 defects. No foreign body reaction was observed in any case. At the intrabony defects mean PD reduction was 5 mm (P < 0.001), and mean gain of CAL was 4 mm (P < 0.001). Mean VOL was 4.3 mm (P < 0.001), mean gingival recession was 0.9 mm (P < 0.05) and mean AC was 0.2 mm (NS). At the Class II furcation defects the mean PD reduction was 4.5 mm (P < 0.001), mean gain CAL vertical was 3.2 mm and CAL horizontal was 4.5 mm (P < 0.001). Gingival recession averaged 1 mm (NS). A complete closure was observed in 2 out of the 8 defects. At the Class III furcation defects the mean PD reduction was 3.6 mm (P < 0.05) and mean CAL-V gain was 1.5 mm (P < 0.02). However the 5 sites showed no horizontal attachment gain and none were unchanged. A very low gingival recession, gingival reaction, crestal bone loss, and device exposure occurred during this study. This preliminary study suggests that the use of a biosynthetic barrier may have beneficial effects in the treatment of intrabony defects and Class II furcation defects. Randomized controlled trials are necessary to evaluate the efficacy and safety of this bioabsorbable membrane in periodontal therapy.

[Development of artificial collagen-elastin conjunctive matrix for tympanoplasty. Concept and 1st results of animal experiments]. / Développement d'une matrice conjonctive artificielle "collagène-élastine" comme matériau de tympanoplastie. Conception et premiers résultats expérimentaux chez l'Animal.

We developed a new biomaterial designed to replaced loss of tympanic tissue. This new material has an original collagen-elastin structure which can be used to create an new artificial conjunctive matrix. The concept and the first experimental results are reported.

[Preliminary results of the evaluation of the Endopatch E-F in digestive surgery]. / Résultats préliminaires de l'évaluation de l'Endopatch E-F en chirurgie digestive.

Endopatch E-F is a new product elaborated with natural human and animal proteins. Its synthesis originates in a covalent link between elastin and fibrin monomers. Numerous experimental studies carried out in animal have previously shown its ability to reinforce healing process of digestive wall. The results reported herein have been obtained in very selected patients in whom a digestive anastomosis had to be done in spite of unfavorable circumstances, such as intra-abdominal infection, radiated bowel or ascitis. From October 1990 to October 1992, 21 digestive anastomosis have been performed in 18 patients. All were reinforced by Endopatch E-F. Two deaths have been observed (mortality: 11.1%), which do not look like a consequence of the use of the product (One myocardial infarction and one cirrhotic failure). There were 2 post-operative fistulas (9.5% of the whole anastomosis). No patients had any reaction of intolerance. These preliminary results confirm experimental data, and suggest that Endopatch EF can be used in order to reinforce digestive sutures when performed under unfavorable circumstances.

[Substitution for an experimental duodenal substance loss in the dog with an original bioreactive material]. / Comblement d'une perte de substance duodénale expérimentale chez le chien par un matériau bioactif original.

The aim of this study was to evaluate the suitability of the Elastin Fibrin material as a patch to close a full thickness 1.5 cm diamater duodenal wall defect in the dog. This material originates from a reaction between elastin and fibrin monomers and is available in sheet form of differing thickness. Three Beagles underwent surgical creation of a duodenal defect ant the patch closure with elastin fibrin. Coelioscopic check of the patch was performed at day 8, 15, 39, 60, 90, 120. There was no morbidity or mortality. Macroscopic and histologic examination showed complete disappearance of the patch material and restitution of the duodenal wall at 6 months. These results suggest that in selected cases, evaluation in human may be justified.