WO1993008265A2 - Production of bone and nacre from bone-forming cells in the presence of nacre - Google Patents

Abstract

According to the invention the artificial fabrication method for fabricating simultaneously or separately bone and nacre is implemented by the activity of osteonacrigenic factors contained in nacre. The method according to the invention consists in using fragments of nacre or powder of nacre resulting from the test of bivalve aquatic Mollusca Gasteropoda or Cephalopoda in the 'in vitro' or 'in vivo' presence of bone cells or bone-forming cells or cells susceptible of becoming bone-forming cells, associated to one or a plurality of bone fragments. The method according to the invention may be implemented in molds of various shapes and sizes, whereafter the bone parts thus obtained may be used as grafts in bone surgery and the nacre may be used to produce pearls, jewels or objects.

Description

PRODUCTION OF BONE AND PEARL. FROM FORMATORY CELLS OF BONES PRESENTED OF NACRE -

The present invention relates to a method for producing natural bone and mother-of-pearl from bone-forming mother-of-pearl cells from the aquatic mollusc test. To date, it has never been possible to artificially produce a sufficient quantity of bone tissue of animal or human origin intended to serve as a graft. The surgical circumstances that can give rise to the need for bone grafts are numerous: orthopedic surgery, trauma or plastic repair surgery, neurosurgery, carcinology eu; ... Dan ^ - all cases, the grafts come from: - either from the patient itself and in this case an autograft is performed - that is, a bone bank made up of bone parts free of their organic part which can cause immune reactions sterilized by ionizing radiation and frozen. In this case, a heterograft is performed. These bone pieces, once grafted, constitute a mineral framework in which it is supposed to develop a process of new bone formation. The disadvantages associated with bone grafts are of several orders, however the most important are the difficulties of supply and storage as well as the immune reactions of rejection, and the obvious risks of infectious and viral contamination. In the case of autografting, the major drawback lies in particular in the fact that one cannot have bone fragments of sufficient volume when it comes to replacing a large loss of substance. This is the reason why certain inventors have proposed bone pieces produced in biologically compatible natural biomaterials, such as coral. These biomaterials can in fact only serve as a calcium reserve. They occupy the volume left empty by the loss of bone substance, and, little by little, are replaced by newly formed bone. The major problem associated with these types of biomaterials comes from the fact that the resorption power of the so-called "osteoclast" bone cells is exhausted, thereby limiting the total colonization of the biomaterial by the bone-forming cells, consequently, by newly formed bone. Other inventors have proposed, as bone substitute parts, elements machined from the nacreous test of certain molluscs, this nacreous test not being absorbed in the intraosseous position. Furthermore, obtaining cultured pearls by bivalve molluscs producing nacre is done from nacre fragments which are introduced into a specific organ of the living mollusc. The inclusion of such a fragment produces an irritant phenomenon _r which itself induces mineralization process by affixing newly formed pearl nacre around the foreign fragment. The pearls thus obtained being of various shapes. However, we have found, and this is the subject of the invention, a simple and rapid process for the simultaneous or separate production of bone and mother-of-pearl which can lead to the formation of pearls.

The invention will be better understood on reading the description of a few examples of embodiments.

The production protocols relating to the process according to the invention are as follows: A layer of cells phenotypically and biochemically recognized to be bone-forming cells (osteoblasts) is placed in an appropriate culture medium: -1) Particles of mother-of-pearl or mother-of-pearl powder

-2) Bone fragments and pearl fragments. In a particular situation. In the first case, physiological normal bone formation is observed in several places in the culture and at a distance from the fragments of mother-of-pearl. In the second case a) An increase in volume of the explant by apposition of newly formed bone and formation of bone fragments in the immediate environment of the bone and mother-of-pearl. b) An increase in volume of the mother-of-pearl fragment by affixing neoformed mother-of-pearl and of mother-of-pearl fragment in the immediate environment of the mother-of-pearl and the bone.

The study by microspectroscopy (RAMAN effect) showed that the mineral deposit of the newly formed mother-of-pearl is very characteristic and specific of this substance. The study with the electron microscope, with the photon microscope in polarized light, by immunocytology and radiology has shown that the neo-formed bone is of the same nature as the initial bone fragment with the presence of bone-specific coUagen and mineral According to another embodiment, the method according to the invention has been implemented in animals. Fragments of mother-of-pearl or mother-of-pearl powder were placed according to a specific protocol in the presence of bone cells which form bone or are supposed to be able to do so. In all cases, the formation of newly formed bone with all the characteristics and specificities of physiological bone was observed. The methods according to the invention demonstrate:

- The presence in the nacre of osteogenic factors, nacrigens (osteonacrigens) and or inducers of diffusible biomineralization and having a remote action.

- The production, by bone cells which form or are likely to be bone, under the effect of these factors, of an organic matrix serving as support both for bone formation and for the formation of mother-of-pearl, therefore containing substances of different types of biomineralization.

The presence of one or more of these factors is essential for the implementation of the method according to the invention. In these methods according to the invention, the bone-forming cells are derived from bone fragments originating from different groups of vertebrates in particular, from human bone. Mother-of-pearl comes from the pearly test of bivalve, gastropod or cephalopod aquatic molluscs. The method according to the invention can be implemented in modules of variable size and shape. These modules will serve as molds in which the method according to the invention will develop in order to obtain replicas of bone or mother-of-pearl. According to a preferred embodiment, the method according to the invention can, on the one hand, lead to the manufacture of bone pieces intended to serve as grafts in bone surgery and, on the other hand, to the production of mother-of-pearl, pearls, jewelry and mother-of-pearl objects, of variable shape and size without this being limiting. These embodiments presented by way of non-exhaustive example, it is up to the person skilled in the art to put in the presence of bone cells which form bone or are likely to become it coming from various groups of vertebrates, in particular from humans. , and fragments of mother-of-pearl or mother-of-pearl powder, obtained from pearly tests of aquatic molluscs, whenever it will need to produce artificially either bone or mother-of-pearl.

Claims

- 4 - 1) Process for the manufacture of bone or mother-of-pearl, characterized in that it is carried out in vitro in vivo from the action of factors inducing biomineralization known as "osteonacrigens" released by fragments of mother-of-pearl placed, either in the presence of bone cells that form or are likely to become bone, either in the presence of the same types of cells to which bone fragments are added. 2) Method according to claim 1 characterized in that the nacre fragments and the nacre powder come from the pearly test of bivalve molluscs, gastropods and cephalopods. 3) Method according to claims 1 2, characterized in that the bone fragment, bone cells bone forming or likely to be from a variety of vertebrate groups including humans. 4) Method according to claims I, 2 and 3 characterized in that the cultures of bone-forming cells or likely to be, are contained in molds of varying shapes and sizes, intended to obtain replicas of bone or mother-of-pearl. 5) Use of bone cells which form or are likely to become bone, and fragments of mother-of-pearl or mother-of-pearl powder for the artificial manufacture of physiologically normal bone. Use of bone cells that form or are likely to become bone and fragments of mother-of-pearl or mother-of-pearl powder for the artificial manufacture of mother-of-pearl.