WO2019229392A1 - Matrix for preparing a cell, tissue and/or bone regeneration composition - Google Patents

Abstract

Matrix (7) for preparing a cell, tissue and/or bone regeneration composition, characterised in that it comprises: - a porous fibrous layer (4) comprising hydrated calcium alginate fibres, said fibrous layer (4) being capable of being seeded by cells (8), and - a gelled barrier layer (6) which comprises alginate and is capable of holding the cells (8) in the fibrous layer (4).

Description

 MATRIX FOR THE PREPARATION OF A CELLULAR, TISSUE AND / OR BONE REGENERATION COMPOSITION

The subject of the present invention is a matrix for the preparation of a cellular, tissue and / or bone regeneration composition that can be used for pathological or traumatic repair or prevention. It is a biomaterial that can be used as a support for tissue engineering. The matrix is intended to be seeded or not with cells, with or without addition of growth factors, so as to obtain said regeneration composition. The composition can be used in general for reconstituting injured tissue and particularly for repairing hard tissue, such as bone tissue or cartilage, at a damaged tissue area.

 During an injury, whether traumatic, pathological or induced, complex physiological mechanisms are established for tissue repair and healing. These mechanisms involve many phases and are the result of complex interactions between cells or between cells and an extracellular matrix involving or not growth factors, microenvironment and activation of specific cell signaling pathways. These interactions can be increased, accelerated, or inhibited by various elements such as hemostatic agents, drugs or growth factors.

Today, surgeons, whether in ophthalmology, stomatology, orthopedics, cardiovascular surgery, urology, nephrology, or plastic surgery, use biomaterials in their therapeutic strategies. Regenerative medicine is important to meet the growing needs in all these areas. Regenerative medicine is defined as a multidisciplinary approach that involves not only tissue engineering, but also chemistry, biomaterial science, biomechanics, and biotherapies with the discovery of stem cells. It offers many perspectives for the replacement of damaged tissues and the prevention of certain pathologies.

 The principle of tissue engineering is to use a biomaterial, to seed it with appropriate cells, to add or not to add biologically active molecules to create a three-dimensional environment necessary and adapted to survival, proliferation, differentiation and the cellular organization towards the tissue to be regenerated. Many works have been implemented to produce biomaterials capable of supporting the formation of these new tissues.

 While this objective seems rather simple, its implementation is particularly complex and represents a challenge that involves many scientific and technological fields. This includes choosing the ideal biomaterial having a supportive structure compatible with tissue and extracellular matrix element, so that the cells can organize and form a valid tissue. The biomaterial must also allow cell-cell interactions between the cultured cells and the host cells, and provide a particular physiological and physical microenvironment for controlling cell functions and controlling the cell cycle (proliferation, differentiation and functionalization) . It is possible to add or not to molecules capable of promoting their growth, their differentiation and to integrate the mechanical constraints to which the new fabric must bend.

The biomaterial, the matrix, is a support acting as a biological tissue that allows the adhesion of cells, their migration, proliferation and differentiation. A biomaterial used in regenerative medicine must therefore meet many characteristics. He must :

 - be biocompatible and therefore not degrade the biological environment in which it is found or interfere with it;

 - be bioactive to allow cellular development;

 - have defined physicochemical characteristics: for example it must be porous to promote cell growth, allow the passage of nutrients and the elimination of waste products;

 - to mimic the cellular microenvironment specific to each tissue;

- be able to withstand the specific mechanical stresses of the damaged tissue.

 There are two main classes of biomaterials: natural biomaterials and synthetic biomaterials.

 Certain natural biomaterials such as collagen, fibrinogen and hyaluronic acid have the property of being components of the native extracellular matrix, their main quality being their excellent biocompatibility.

 Synthetic biomaterials have various advantages, including being able to be produced on a large scale, with a controlled manufacturing process, and are therefore less expensive. On the other hand, these biomaterials are generally easily manipulated. However, the use of these products can generate inflammatory reactions because these products are recognized as foreign body by the immune system of the recipient.

Preclinical studies and a few rare clinical trials demonstrate the ability of "matrices", consisting of a bio-resorbable carrier composed of natural derivatives or synthetic materials and one or more cell populations, to assist in the process of tissue repair with synthesis for example cartilage or bone, once these matrices implanted within a lesion. However, it remains improve the interface between materials and biological media, in particular by controlling the macrostructure of the material (pore size, morphology, distribution), to allow bioactivity and biofunctionality.

 Different cell types, alone or in combination, have already been tested in the context of tissue regeneration: embryonic stem cells (ES cells), of fetal origin (cord blood, umbilical cord or placenta) or isolated from adult stem cells ( CSA), induced pluripotent stem cells (iPS) or somatic cells. Whatever the origin and the type of cells used, the mechanisms of regeneration of the tissues make use of the paracrine effects and / or integration - direct participation of these implanted cells in the formation of the damaged tissue.

 The embryonic stem cells derived from the embryo at a very early stage of its development are endowed with two important capacities: that of multiplying to infinity, by simple division (self-renewal), and that of giving birth to all types of embryos. cells of the body (pluripotency).

 Induced pluripotent stem cells called iPS (for "induced pluripotent stem cells" in English) are obtained after removal of virtually any adult cell type and genetic reprogramming to restore this pluripotency capability. The iPS are thus able to multiply to infinity and differentiate into the types of cells that make up an adult organism, just like an embryonic stem cell.

 Given the ethical issues and safety constraints, CSEs and iPS have been used instead to study tissue formation or fundamental mechanisms of development and are excellent models for understanding pathological phenomena.

Multipotent stem cells have the ability to differentiate into several cell types. Among these cells, stem cells mesenchymal (CSM), isolated from fetal or adult tissues, are the most used for tissue engineering and can differentiate into osteoblasts, chondrocytes, adipocytes and myocytes in vitro.

 The number of patients requiring surgical bone reconstruction continues to grow, and orthopedic or maxillofacial surgeons are looking for simple techniques and materials that ensure perfect biosafety for the patient. About 2.2 million bone grafts are performed each year worldwide. Bone is an organ whose cellular composition is complex. It is highly vascularized and subject to constant remodeling. The mineralized matrix of bone is composed of an organic phase (representing 35% of the dry weight of the matrix) mainly composed of collagen responsible for its rigidity, viscoelasticity and strength, and other proteins that form the necessary microenvironment cell functions, and a mineral phase of apatite carbonate (representing 65% of the dry weight of the matrix) for the structural reinforcement, its rigidity and mineral homeostasis. The bone has intrinsic abilities of spontaneous consolidation after injury. However, in case of excessive lesions, it is necessary to intervene and the tissue transplantation and the auto transplants still remain the most used strategies. But the morbidity of the donor site (pain, inflammation, infections) and the amount of bone available are the limits of these therapeutic approaches.

 Today, there is no reference bone substitute despite preclinical and clinical studies demonstrating the ability of these matrices to assist in the process of bone tissue synthesis. The surgeon's choice is therefore based on his knowledge and the convictions of the patient who may prefer substitutes of natural origin and not of animal origin.

The ideal matrix will be a support acting as a biological tissue (supporting tissue and extracellular matrix) that will respond to all the criteria mentioned above and which will in this case allow osteoconduction and osteoinduction.

 The present invention aims to remedy the disadvantages mentioned above, by providing a matrix for the preparation of a cellular, tissue and / or bone regeneration composition, the matrix being in particular biocompatible and allowing good viability of the host cells and / or seeded cells.

 The subject of the invention is thus a matrix for the preparation of a cellular, tissue and / or bone regeneration composition.

 The matrix according to the invention comprises:

 a porous fibrous layer comprising hydrated calcium alginate fibers, said fibrous layer being capable of being seeded by cells, and

 a gelled barrier layer comprising alginate, able to maintain the cells in the fibrous layer.

 Thus, the fibrous layer allows cell culture, while the barrier layer, adjacent to the fibrous layer, serves as a support cell culture without risk of dissemination and thus loss of cells in the medium at the time of preparation.

 Alginic acid and its derivatives (base conjugates, salts and esters) alginates are polysaccharides mainly obtained from a family of brown algae: laminaria or fucus.

 Alginate is the common name for a family of polymers consisting of two monomers bonded together: mannuronate or mannuronic acid and guluronate or guluronic acid.

 The general formula of alginate is as follows:

La proportion et la distribution de ces deux monomères sont déterminantes pour une large expansion des propriétés physiques et chimiques de l'alginate, on parle ainsi de rapport mannuronique gluronique ou encore de rapport M/G. La composition chimique de l’alginate varie selon les diverses espèces d'algues, les différentes parties de la même plante et est sujette aux changements saisonniers. Néanmoins, par sélection de matières premières aux différentes propriétés, il est possible de fabriquer une variété d'alginate aux caractéristiques constantes.

The proportion and distribution of these two monomers are decisive for a broad expansion of the physical and chemical properties of alginate, so-called gluronic mannuronic ratio or M / G ratio. The chemical composition of alginate varies among different species of algae, different parts of the same plant and is subject to seasonal changes. Nevertheless, by selecting raw materials with different properties, it is possible to manufacture a variety of alginate with constant characteristics.

 The fibrous layer may comprise calcium alginate and sodium fibers, and the barrier layer may comprise sodium and calcium alginate.

 The level of calcium complexed with alginate in the fibrous layer is preferably greater than the calcium level complexed with alginate in the barrier layer.

 The level of sodium complexed with alginate in the fibrous layer is preferably lower than the level of sodium complexed with alginate in the barrier layer.

 The hydrated calcium alginate fibers can be obtained by impregnating calcium alginate fibers with a (aqueous) sodium salt solution.

 The barrier layer can be obtained by mixing the fibrous layer with an alginate salt or a sodium salt.

The hydrated calcium alginate fibers being obtained by hydration of calcium alginate fibers in the dry state, the weight per unit area of the calcium alginate fibers in the dry state is advantageously less than or equal to 170 g / m ² , preferably between 120 and 170 g / m ² . A surface mass greater than or equal to 120 g / m ² makes it possible to make the matrix less fragile and to handle it more easily, while a surface density of less than or equal to 170 g / m ² makes it possible to obtain a matrix less dense, with optimal cell penetration. The calcium alginate fibers may be selected from calcium alginate, calcium alginate / manganese, calcium / silver alginate, and calcium alginate / chitosan fibers.

 The gelled barrier layer may comprise sodium alginate or an alginate derivative. The gelled barrier layer may further comprise an alginate derivative, a cellulose derivative, a poloxamer or a derivative thereof, collagen, gelatin, chitosan or a derivative thereof.

 The matrix can be obtained by hydrating a lyophilized or dried composition of hydrated calcium alginate fibers. Hydration can be performed with a solution of sodium alginate.

 The subject of the invention is also a cellular, tissue and / or bone regeneration composition.

 The composition according to the invention comprises a matrix described above and cells. Preferably, said cells are not human embryonic stem cells.

 The invention also relates to a composition described above for use for cellular, tissue and / or bone regeneration.

 The subject of the invention is also a process for obtaining a matrix described above.

 The method comprises the following steps:

 impregnating calcium alginate fibers with a solution (aqueous) of sodium salt, so as to obtain hydrated calcium alginate fibers, and

 contacting the hydrated fibers with a solution of sodium alginate.

The method may further comprise a step of seeding the matrix obtained with cells. Preferably, said cells are not human embryonic stem cells. The invention will be better understood and other details, characteristics and advantages of the invention will appear on reading the following description given by way of nonlimiting example and with reference to the appended drawings in which:

 FIG. 1 diagrammatically illustrates the various steps of a method for obtaining a matrix according to the invention, and

 - Figure 2 schematically illustrates a matrix according to the invention seeded with cells.

 The matrix according to the invention is a hydrogel structured bilayer, the two layers being distinct and cohesive. It is thus advantageously composed of a layer of calcium and sodium alginate fibers hydrated, called fibrous layer, and a layer of calcium alginate and calcium dense and non-porous, called gel layer. This matrix presents the same type of chemical environment: two layers both containing alginate in calcium or sodium form but with different ionic proportions. In the fibrous layer, the calcium level complexed with alginate is greater than that of the gel layer. Conversely, the sodium level is higher in the gel layer relative to the fibrous layer.

 The gelled layer necessarily contains alginate but may further comprise one or more polymers, such as an alginate derivative, a cellulose derivative, a poloxamer or a derivative thereof, collagen, gelatin, chitosan or a derivatives, in order to improve, for example, the mechanical properties of this layer.

The side composed of partially gelled alginate fibers (the fibrous layer) is of controlled density and has pores. The density control is done during the manufacturing process by choosing the constituent elements of the fibrous layer. This fibrous layer has an architecture and environment conducive to the culture or co-culture of different cell types (with or without growth factors), their survival, proliferation, differentiation and three-dimensional organization in vivo.

 The gelled layer is advantageously very dense and non-porous, the cells can not integrate and cross.

 Thus, the cells will therefore colonize only the fibrous layer of the matrix, the gel layer serving as a support for the fibrous layer limiting the loss of cells in the in vitro dissemination medium and thus the loss of cells during seeding.

 This bilayer matrix may also contain proteins, growth factors, hormones, vesicles, in order to improve cell viability, proliferation and differentiation according to the cell type used.

 The bilayer matrix can be seeded with cells, with or without growth factors.

 This seeding must be performed on the fibrous layer and therefore having the highest porosity. The cells are then able to penetrate to the heart of the matrix. They will be retained by the second layer, dense, which acts as a barrier. The matrices thus seeded are cultured in a culture medium adapted and specific to the cells chosen, whether or not containing growth factors, and allowing the viability and proliferation of the cells within the fibrous layer.

 The gelled layer retains the cells on the fibrous portion or at the interface. Chemical continuity ensures good cell survival in the matrix.

 The alginate bilayer matrix can be seeded with different cell types, with or without growth factors, depending on the tissue to be regenerated:

- somatic cells (adults and differentiated) used for their release of growth factors or molecules involved in the maintenance of the microenvironment, differentiation, inflammatory response or migration of other cell types;

 - Adult stem cells whose ability to differentiate into a cell type is interesting depending on the tissue to be regenerated (circulating endothelial progenitors (CEP), muscle stem cells ...);

 multipotent stem cells capable of differentiating into several cell types of several embryonic leaves. Among these cells, and given their proliferation and differentiation capabilities, mesenchymal stem cells (MSCs) are widely used. Present in the bone marrow and in different tissues, they are easily isolatable and have a great capacity for proliferation and differentiation. Moreover, it has now been demonstrated that these cells, integrated into a matrix, participate in the morphogenesis of bone tissues or their role in the stimulation and recruitment of microenvironmental cells by paracrine action;

 - embryonic stem cells or pluripotent iPS cells capable of dividing to infinity and differentiating into all tissues of the human body.

 The cells may be stem cells, preferably stem cells selected from the group consisting of embryonic stem cells, pluripotent stem cells and adult stem cells, more preferably induced pluripotent stem (iPS) cells and / or adult stem cells. (THAT'S IT). Preferably, embryonic stem cells are not human embryonic stem cells.

In one embodiment, the cells are not human embryonic stem cells obtained through the de novo destruction of human embryos or using publicly available human embryonic stem cell lines that initially originate from a process resulting in the destruction of embryos. humans. Combinations and cocultures can be implemented in this matrix.

 For example, mesenchymal stem cells may be co-cultured with other cell types such as endothelial cells (EC) or mononuclear cells (CMNs) containing, inter alia, EC precursors. Numerous publications indeed demonstrate the functional benefit of the integration of several cell types in the matrices and their paracrine effect. In addition, the culture medium may be supplemented with different growth factors (VEGF, IL1 for example).

 A method of preparing the matrix will now be described, in connection with FIGS. 1 and 2.

 The base material is advantageously interleaved (non-woven) calcium alginate fibers 1 having a certain basis weight.

 In a first step, and as shown in Figure 1, these fibers 1 are impregnated in a tank 3 with a certain volume of saline solution of known concentration, for example sodium. After a certain contact time, under the action of the salts 2, the calcium alginate will partially gel by ion exchange. It is thus obtained fibers of pluriionic alginate 4, for example of calcium-sodium alginate, and free calcium. Depending on the initial basis weight, at the end of this step, a higher or lower porosity will be obtained: the higher the initial basis weight, the lower the final porosity and vice versa.

In a second step, the partially gelled fibers 4 will then be brought into contact with a known volume of one or more ionic polymers of determined concentration. During this step, following ion exchange between the free calcium present in the hydrated fibers 4 and the ions contained in the solution 5, there is weak ionic crosslinking of the alginate, thus forming in situ the gelled layer 6 and the bilayer hydrogel will develop creating the matrix 7. Finally, after dewatering, a matrix 7 composed of a layer 4 of partially gelled fibers having a certain porosity and a layer 6 of dense alginate gel having a very low porosity, the two layers 4 and 6, is finally obtained. being adjacent and integral with each other. This matrix 7 may thus be provided for seeding or not of cells 8 and used in the patient or for research purposes (FIG. 2).

The fibrous portion is obtained by partial solubilization of intertwined calcium alginate fibers. The initial basis weight has a direct impact on the final porosity of this layer. Indeed, the higher the initial basis weight, the lower the final porosity and vice versa. The grammage is preferably less than or equal to 170 g / m ² . The porosity of the matrix can therefore be controlled and modified to obtain an ideal porosity according to the cell type to be seeded. The control of the porosity via the initial grammage of the interlocked alginate fibers allows the production of a stable and homogeneous bilayer matrix between different batches of matrices.

 It is also possible to lyophilize or dry the calcium alginate fibers hydrated with the saline solution at the end of the first stage. Once lyophilized or dried, these fibers can be sterilized by irradiation, for example by beta radiation. The fibers will be provided to the future user. This one will have to rehydrate them with a solution of ionic polymers to obtain a matrix bilayer.

 Freeze-drying or drying the matrix makes it possible to sterilize it, and therefore to have a product free of bioburden, which is not likely to degrade over time and lose its physico-chemical characteristics. This freeze-dried or dried matrix thus has the advantage of having a later expiry date.

The user will have at his disposal either a freshly fabricated matrix, directly usable, or a kit consisting of a dehydrated matrix and a solution of one or more polymers. The cells are then seeded on the surface of the bilayer matrix, on the side composed of hydrated alginate fibers and therefore having the highest porosity. The cells will then penetrate to the core of the matrix and be retained by the second gelled layer having a very low porosity. The matrices thus seeded are brought into contact with suitable culture medium, supplemented with growth factors, allowing the viability and proliferation of the cells.

 Once the matrix is colonized by the cells, the surgeon will be able to implant it in the patient's damaged tissue area. Depending on the type of injury and the opinion of the surgeon, either the complete matrix, with the gel layer and the fibrous layer, will be implanted, or the two layers of the matrix will be separated and only the fibrous layer, containing the cells, will be preserved. to be implanted. The surgeon will also be able to implant in the patient the matrix alone, with or without biologically active molecules, without prior seeding of cells.

 The invention is illustrated in a nonlimiting manner by the following example.

Example: preparation of a bone and tissue regeneration composition

A bilayer matrix is cut into 0.5 x 0.5 cm samples. Each sample was rinsed twice for 3 to 4 hours at a temperature of 37 ° C in culture medium EGM2 ^®, specific culture medium for endothelial cells, commercially available from Lonza. The samples are deposited in culture wells, fibrous face on top.

The cells used in the case of bone regeneration can be: - mesenchymal stem cells (MSCs) present in bone marrow, adipose tissue, cord blood or in umbilical cord jelly. Their in vitro characteristics are: the adhesion to the plastic support, the expression of the CD73, CD90 and CD105 surface markers and the absence of expression of the markers CD34, CD45, CD19 and HLA-DR. They have the ability to differentiate into osteoblasts, adipocytes and chondrocytes in vitro;

 - endothelial cells (EC) from progenitors of the cord blood. These cells form the vessel wall, control vascular tone and play a role in neoangiogenesis. They are mobilized from the bone marrow, derived from circulating endothelial progenitors. These cells have demonstrated their ability to differentiate into several types of endothelial cells and synthesize factors essential for hemostasis and other cellular processes.

 In coculture, these two cell types cooperate. Indeed, endothelial cells increase, in vitro and in vivo, the osteogenic differentiation of mesenchymal stem cells and mesenchymal stem cells stimulate the survival and growth of endothelial cells by paracrine action. One study demonstrated that the ratio of mesenchymal stem cells to endothelial cells was important for cell survival and proliferation.

 For this case of bone regeneration, several seeding were tested:

- human MSC alone (1 million cells on 0.25 cm ² );

- human EC alone (1 million cells on 0.25 cm ² );

a 50/50 CSM / EC co-culture of human origin (500,000 cells of each cell type over 0.25 cm ² ).

The matrices are cultured in each well in EGM2 ^® culture medium (growth medium specific for endothelial cells, rich in growth factors, EGF, IGF, VEGF, bFGF, etc.). This culture medium can be supplemented with growth factors (VEGF for example) to allow a better proliferation of cells. The cells are thus left in culture for 24 to 96 hours at a temperature of 37 ° C. and with 5% of C0 ₂ .

 The cells colonize the entire fibrous layer of the matrix: the gelled layer effectively and sustainably retains the cells in the fibrous layer without cell loss.

 Prior to culturing the cell membranes were labeled with PKH-type dyes (initials of their creator, Paul Karl Horan), such as those described in the publication Duttenhoefer F et al, 2013, European Cells and Material, for enable monitoring of cell viability.

 After 24 hours, the viability of MSCs is estimated to be at least 95% and 60% for the EC. After 96 hours, MSCs and ECs are viable. Cell viability is greater when CSM and CE cells are cocultivated in the matrix.

For a matrix made from a non-woven calcium alginate having a grammage too high (greater than 170 g / m ² ), it is found that the matrix becomes less porous and seeded cells penetrate more difficultly into the matrix. The cells then form a mat on the surface of the matrix.

Implantation of the matrix: in vivo test

Once the matrix colonized by the cells, after 24 hours, the two layers of the matrix are separated. Only the fibrous layer, containing the cells, is conserved and is implanted subcutaneously on the flank of immunodepressed nude mice. The mice are followed for two months, and weighed twice a week. The weight gain of the mice over time remained steady, and no abnormal behavior of the mice in the cage was observed. Moreover, after implantation of the fibrous layer, no inflammatory or infectious phenomenon has been observed, the matrices having been very well tolerated. No mouse died. After two months, the mice are sacrificed, the implants removed and the cells present identified.

 Specific markings of human and murine cells have shown that:

 two months after implantation, initially included human EC and CSM cells are found in the matrix;

 the matrices are colonized with mouse MSCs (no endothelial cells found);

 a synthesis of collagen matrix, without any significant difference between the conditions, is observed;

 the human ECs formed a vessel demonstrating the proliferation and organization of the cells between them within the matrix after two months of implantation.

 These results demonstrate that this matrix is an adequate support allowing the viability, proliferation and functionality of the cells as well as colonization by the recipient cells with an interaction between seeded cells and host cells.

Claims

1. Matrix (7) for the preparation of a cellular, tissue and / or bone regeneration composition, characterized in that it comprises: a porous fibrous layer (4) comprising hydrated calcium alginate fibers, said fibrous layer (4) being capable of being seeded by cells (8), and  a gelled barrier layer (6) comprising alginate, able to maintain the cells (8) in the fibrous layer (4).  2. Matrix (7) according to claim 1, characterized in that the fibrous layer (4) comprises calcium alginate and sodium fibers, and in that the barrier layer (6) comprises sodium alginate and calcium.  3. Matrix (7) according to claim 2, characterized in that the calcium level complexed with alginate in the fibrous layer (4) is greater than the calcium level complexed with alginate in the barrier layer (6).  4. Matrix (7) according to claim 2 or 3, characterized in that the level of sodium complexed with alginate in the fibrous layer (4) is lower than the level of sodium complexed with alginate in the barrier layer (6). ).  5. Matrix (7) according to one of claims 1 to 4, characterized in that the hydrated calcium alginate fibers are obtained by impregnating calcium alginate fibers (1) with a sodium salt solution ( 2).  6. Matrix (7) according to one of claims 1 to 5, characterized in that the barrier layer (6) is obtained by mixing the fibrous layer (4) with a sodium salt. 7. Matrix (7) according to one of claims 1 to 6, characterized in that the hydrated calcium alginate fibers being obtained by hydration of calcium alginate fibers in the dry state, the mass Calcium alginate fiber in the dry state is less than or equal to 170 g / m ² .  8. Matrix (7) according to one of claims 1 to 7, characterized in that the calcium alginate fibers (1) are chosen from calcium alginate, calcium alginate / manganese fibers, d alginate calcium / silver, and calcium alginate / chitosan.  9. Matrix (7) according to one of claims 1 to 8, characterized in that the gelled barrier layer (6) comprises sodium alginate or an alginate derivative.  10. Matrix (7) according to one of claims 1 to 9, characterized in that it is obtained by hydration of a lyophilized or dried composition of hydrated calcium alginate fibers.  11. Cell regeneration composition, tissue and / or bone, characterized in that it comprises a matrix (7) according to one of claims 1 to 10 and cells.  12. Composition according to claim 11, characterized in that said cells are not human embryonic stem cells.  13. The composition of claim 11 or 12 for use for cellular, tissue, and / or bone regeneration.  14. Process for obtaining a matrix (7) according to one of claims 1 to 10, characterized in that it comprises the following steps:  impregnating calcium alginate fibers (1) with a solution of sodium salt (2) so as to obtain hydrated calcium alginate fibers (4), and  contacting the hydrated fibers with a solution of sodium alginate (5). 15. The method of claim 14, characterized in that it further comprises a step of seeding the matrix (7) obtained with cells (8). 16. The method of claim 15, characterized in that said cells (8) are not human embryonic stem cells.