CN2830410Y - tissue engineered peripheral nerve graft - Google Patents

Abstract

The utility model discloses a tissue engineering peripheral nerve graft to provide a surgical graft for repairing nerve defect with wider application range and better quality. The tissue-engineered peripheral nerve graft described in the utility model includes a scaffold used to connect the two broken ends of the nerve and seed cells with the function of promoting nerve regeneration. The seed cells are attached to the scaffold to form a three-dimensional structure with imitation nerve and biological activity. complex. The scaffold is decellularized allogeneic nerve, and the seed cells are adult stem cells. The utility model is a tissue-engineered peripheral nerve graft in the true sense, which not only provides a bionic channel for the regenerated nerve fibers to pass through the nerve defect area, but also its internal seed cells can promote nerve regeneration, so it can be used for repairing For longer-distance nerve defects, the effect of nerve repair is significantly improved, and the clinical application range is wider.

Description

tissue engineered peripheral nerve graft

technical field

The utility model relates to a surgical graft, in particular to a nerve graft used for repairing peripheral nerve defects.

Background technique

Peripheral nerve injury and the nerve defect caused by the injury are common clinical disabling diseases. The repair of peripheral nerve injuries caused by various accidents has always been a difficult problem in neurosurgery. There are nearly 1 million new cases in my country every year, of which about 450,000 cases need to be repaired by implanting nerve grafts. At present, the sources of neural grafts are very scarce, and there is an urgent need for research and development of neural substitutes.

The development of nerve grafts at home and abroad has been stuck on catheters with imitation nerve structures. At present, the artificial products developed are tubular medical materials that connect the two stumps of nerves, which are so-called "artificial nerve tubes" or "artificial nerve tubes". Artificial Nerve Grafts". In the Chinese patent "medical artificial nerve graft and its preparation method" (patent number: 01108208.9), a biological catheter made of chitosan material is disclosed. The biological catheter is embedded with a fiber scaffold, and the fiber scaffold material is polyglycolic acid or polylactic acid; in the Chinese patent application "artificial nerve tube" (application number: 00810000.4), "artificial nerve tube" (application number: 99807035.1), "artificial nerve tube" (application number: 97199928.7) all disclose the The tube formed by decomposing the absorbent material has fine fibrous collagen in the lumen, and the interstices are filled with laminin.

The above-mentioned existing products are all catheters made of degradable biomaterials, which can "bridge" the defective nerves after implantation in the body, but the above-mentioned products only provide a "bridge" or a "bridge" for the growth of regenerated nerve axons. The "channel" itself has no biological activity, cannot provide the necessary internal environment for nerve growth, and has no effect on promoting nerve regeneration.

Modern medicine has confirmed that Schwann cells play an extremely important role in the growth of human nerves. They attach to and surround axons to form myelin sheaths and promote the extension and maturation of axons. Because the above-mentioned existing products do not provide Schwann cells necessary for nerve regeneration or active cells with similar functions, when new axons grow near the stump, they can only rely on the body's own Schwann cells to grow together. Not only is it very slow, but the migration of the Schwann cells in the body itself has a certain limit. If the Schwann cells cannot enter, or enter very little, the growth of the nerve will be greatly affected. If it is applied clinically, it can only repair short distances. Generally, the nerve defect is not more than 15mm. Clinically, such a short-distance nerve defect can often be sutured directly, without the need for these nerve grafts. For longer-distance nerve defects, even if the above-mentioned catheter is "bridged", the regenerated nerve axons cannot reach the distal stump, and the function of the damaged nerve cannot be restored, so the repair effect is very unsatisfactory.

In recent years, the emergence of tissue engineering has brought new hope for the repair of tissue damage. Tissue engineering is a science that uses the principles and methods of engineering and life sciences to study the relationship between normal and diseased mammalian tissue morphology and function, and to develop biological substitutes for repairing damaged tissue morphology and function. It is a science in the field of biotechnology. important content. Specifically, the principle of bionics is used to prepare complexes with specific three-dimensional structures and biological activities to create tissues with normal physiological functions, which can be used to replace the shape and function of human defective tissues. The emergence of tissue engineering marks that medicine will enter a new stage of using artificial tissue and organ transplantation to repair defects and reconstruct functions from the existing autologous or allogeneic tissue and organ transplantation model.

The above-mentioned existing products have no biological activity, and are not tissue-engineered peripheral nerve grafts in the true sense, which is the root cause of the unsatisfactory effect of the existing products in nerve repair.

Contents of the invention

The purpose of the utility model is to provide a tissue-engineered peripheral nerve graft, which is used for repairing nerve defects after peripheral nerve damage.

The tissue engineered peripheral nerve graft described in the utility model includes a scaffold used to connect the two stumps of the nerve and seed cells with the function of promoting nerve regeneration, and the decellularized allogeneic nerve scaffold is composed of multiple decellularized nerve bases The seed cells are attached to the inner wall of the cavity of the nerve basement membrane tube, or attached to the outer surface of the nerve basement membrane tube, forming a complex with a three-dimensional neuromimetic structure and biological activity.

The scaffold is a decellularized allogeneic nerve, preferably a decellularized allogeneic nerve prepared by a chemical extraction method.

In order to further enhance the adhesion of the scaffold to the seed cells, and promote nerve regeneration and graft vascularization, substances that can promote cell adhesion, nerve regeneration and graft vascularization may be added to the decellularized allogenic nerve.

The aforementioned substances that can promote cell adhesion, nerve regeneration, and graft vascularization can be extracellular matrix (ECM), including collagen, aminoglycans, and glycoproteins; they can also be various growth factors.

The seed cells are adult stem cells. Bone marrow mesenchymal stem cells or adipose stem cells are preferred.

Peripheral nerves are composed of nerve cells, Schwann cells, connective tissue, blood vessels, lymphatic vessels, and special supporting cells. A nerve cell (neuron) is composed of a cell body and a protruding cell process. The end of the cell process repeatedly branches and contacts the neuron. The axon is one of the longest and most important cell processes that can extend to the effector . Schwann cells wrap around axons to form nerve fibers. Tens of thousands of fibers gather together to form nerve bundles, and one or several nerve bundles are linked together by connective tissue to form peripheral nerves. When a peripheral nerve is ruptured and a defect occurs, a graft is needed to "bridge" the defective nerve segment, and new nerve axons grow into the graft from the proximal stump, and grow toward the distal stump under the guidance of Schwann cells. Modern medicine has confirmed that Schwann cells play an extremely important role in the growth of human nerves. They attach to and surround axons to form myelin sheaths and promote the extension and maturation of axons. The inventors have successfully attached adult stem cells to the scaffold and transplanted them into the body. In the in vivo environment, the adult stem cells were induced to become cells with the morphology and function characteristics of Schwann cells, named "Schwann-like cells". These cells should be human One of the most suitable seed cells used in the tissue engineered nerve designed for the repair of peripheral nerve injury, its proliferation in vivo paves the way for the regeneration of nerve axons.

The existing so-called "artificial nerve tubes" or "artificial nerve grafts" are only "bridges" or "channels" provided for the growth of regenerated nerve axons, while the tissue engineered peripheral nerve grafts described in the utility model have The breakthrough advantage is the use of "planting" biologically active seed cells on the scaffold connected to the stump of the nerve, which can be induced to differentiate into Schwann's cells in the in vivo environment with the morphology and function The characteristic "Schwann-like cells" have the characteristics of attached growth. The Schwann-like cells can adhere, migrate, and proliferate on the surface of the scaffold to form an artificial neural tissue with a special three-dimensional structure and active cells. Both the scaffold and the seed cells are essential components of the peripheral nerve graft described in the utility model, thereby constituting a real tissue engineered peripheral nerve graft.

The existing "artificial nerve tubes" or "artificial nerve grafts" made of biodegradable materials still have many things to be improved. Such scaffolds made of biodegradable materials are artificial imitations after all. Compared with the structure of natural nerve fibers, their three-dimensional structures are too simple, and the technical cost of processing them into scaffolds with complex structures is very high. Therefore, the utility model adopts the decellularized allogeneic nerve as the scaffold, which can further overcome the defects of the existing biodegradable material catheter.

The utility model is characterized in that the allogeneic nerve is decellularized and its natural nerve basement membrane tube structure is used as a support. The inventors have successfully used chemical drugs to destroy and elute cells in human peripheral nerves to obtain "decellularized allogeneic nerve scaffolds". The treated scaffold only removes various cells in the nerve tissue and retains the nerve basement membrane tube and the matrix between the tubes, and the fiber skeleton of the nerve is still intact.

When the utility model is applied, the tissue-engineered peripheral nerve graft is implanted into the nerve defect site of the human body, and the newborn axons growing from the stump of the nerve start to grow into the bracket and extend and mature in the bracket. During this process, the seed cells attached to the scaffold continue to proliferate and migrate in the direction of the regenerated axon, forming a "Schwann-like cell" band, waiting for the arrival of the new axon, and growing in the new axon. During the process, the seed cells are equivalent to the "guide" that "welcomes" the newborn axons, providing the necessary nutrition and induction. The newborn peripheral nerve axon has one after another Schwann-like cells to "meet" it, surround the axon, form a myelin sheath, and make it functionally mature. At the same time, the decellularized allogeneic nerve as a scaffold is gradually absorbed by the body and eventually replaced by new nerve fibers.

Because the growth of peripheral nerves must be "escorted" by Schwann cells. Existing nerve graft products only provide scaffolds and do not provide Schwann cells or active cells with similar functions. When new axons grow from the proximal stump, they can only rely on the body's own Schwann cells to grow together. The process is not only very slow, but also the migration of the Schwann cells in the body itself has a certain limit. If the Schwann cells cannot enter, or enter very little, the growth of the nerve will be greatly affected. If it is applied clinically, it can only repair short The distance of the nerve defect is generally not more than 15 mm. Clinically, such a short-distance nerve defect can often be sutured directly, without the need for these nerve grafts. For nerve defects with a longer distance, such as more than 3 cm, even if the above-mentioned catheter is "bridged", the regenerated nerve axons cannot reach the distal stump, and it is difficult to restore the function of the damaged nerve, so the repair effect is very unsatisfactory. However, the utility model adopts the combination structure of seed cells and scaffolds, which not only provides a bionic channel for the regenerated nerve fibers to pass through the nerve defect area, but also its internal seed cells can promote nerve regeneration, so it can be used to repair longer The effect of nerve repair is significantly improved and the scope of clinical application is wider.

Description of drawings

Fig. 1 is the structural representation of the utility model.

FIG. 2 is a partially enlarged schematic diagram of the section A-A of FIG. 1 .

Fig. 3 is a schematic diagram of the application of the utility model.

Detailed ways

The tissue engineered peripheral nerve graft described in the utility model, as shown in Fig. 1 and Fig. 2, comprises a support 1 for connecting the two broken ends of the nerve and a seed cell 2 with the function of promoting nerve regeneration, and the seed cell 2 is attached to On the scaffold 1, a complex with a three-dimensional neuromimetic structure and biological activity is formed. Scaffold 1 is decellularized allogeneic nerve. As shown in Figure 2, the decellularized allogeneic nerve is composed of many nerve basement membrane tubes 11, the cells in the nerve basement membrane tubes 11 have been removed, leaving a cavity, and the seed cells 2 are mainly attached to the inner wall of the nerve basement membrane tube 11, It can also be attached to the outside of the nerve basement membrane tube 11. As shown in FIG. 3 , when repairing a nerve defect, the tissue-engineered peripheral nerve graft described in the present invention is implanted between the proximal stump 3 and the distal stump 4 .

In the actual product, the nerve basement membrane tube contained in the decellularized allogeneic nerve is extremely small. Figures 1 to 3 are microscopic schematic diagrams, and their proportions do not represent the proportions of the actual product.

Seed cells 2 are adult stem cells. Adult stem cells include a variety of stem cells, such as bone marrow mesenchymal stem cells and adipose stem cells. The following examples use bone marrow mesenchymal stem cells and adipose stem cells as seed cells to illustrate:

Embodiment one:

Cut the complete nerve from the donor's limb, use chemical drugs (such as trinitrotoluene and sodium deoxycholate, etc.) to destroy the cells in the nerve tissue and extract its cellular components to obtain the decellularized allogeneic nerve, after sterilization as bracket 1. Bone marrow was extracted from the patient's body (such as the iliac crest, tibia, etc.), bone marrow mesenchymal stem cells were isolated, and the isolated bone marrow mesenchymal stem cells were injected as seed cells 2 into the sterilized decellularized allogeneic neural scaffold 1 for in vitro After culturing, the tissue-engineered peripheral nerve graft constructed from bone marrow mesenchymal stem cells and decellularized allogeneic nerves described in the utility model has been obtained. In clinical use, the tissue engineered peripheral nerve graft described in the present invention is implanted into the peripheral nerve defect to be repaired, and the adult stem cells are promoted to differentiate into "Schwann-like cells" in the in vivo environment, and the Schwann-like cells Proliferate and migrate along the growth direction of regenerated axons. As shown in Figure 3, after the peripheral nerve is broken, new axons grow out from the proximal end of the nerve, Schwann-like cells approach and surround the axon, provide nutrition to the axon, and guide the axon to grow toward the distal end of the nerve , connected with the distal end 4 of the nerve fiber. During this process, the Schwann-like cells function as Schwann cells, and the decellularized allogeneic nerve as a scaffold is absorbed by the body and eventually replaced by regenerated nerve fibers.

In order to further enhance the adhesion of the scaffold to the seed cells, and promote nerve regeneration and graft vascularization, in this example, substances that can promote cell adhesion, nerve regeneration, and graft vascularization can be added to the decellularized allogeneic nerve . The substance can be extracellular matrix (extracellular matrix, ECM), including collagen, aminoglycans, and glycoproteins; it can also be various growth factors.

In this example, when the patient's digital nerve defect is 2 cm, an allogeneic digital nerve of corresponding length can be taken as a scaffold for decellularization; when the patient's median nerve defect is 4 cm, a corresponding length of allogeneic median nerve can be taken for decellularization Processing as a scaffold: When the sciatic nerve defect of the patient is 6 cm, the allogeneic sciatic nerve of the corresponding length can be decellularized as a scaffold.

Embodiment two:

Cut the complete nerve from the donor's limb, use chemical drugs (such as trinitrotoluene and sodium deoxycholate, etc.) to destroy the cells in the nerve tissue and extract its cellular components to obtain the decellularized allogeneic nerve, after sterilization as bracket 1. Adipose tissue is extracted from the fat-rich part of the patient's body (such as the abdominal wall), and the adipose stem cells are separated, and the separated adipose stem cells are injected as seed cells 2 on the sterilized decellularized allogeneic neural scaffold 1, and the utility model is obtained. The tissue engineered peripheral nerve graft constructed from fat stem cells and decellularized allogeneic nerves. In clinical use, the tissue engineered peripheral nerve graft described in the present invention is implanted into the peripheral nerve defect to be repaired, and the fat stem cells are promoted to differentiate into "Schwann-like cells" in the environment in vivo, and the Schwann-like cells Proliferate and migrate along the growth direction of regenerated axons. As shown in Figure 3, after the peripheral nerve is broken, new axons grow out from the proximal end of the nerve, Schwann-like cells approach and surround the axon, provide nutrition to the axon, and guide the axon to grow toward the distal end of the nerve , connected with the distal end 4 of the nerve fiber. During this process, the Schwann-like cells function as Schwann cells, and the decellularized allogeneic nerve as a scaffold is absorbed by the body and eventually replaced by regenerated nerve fibers.

In order to further enhance the adhesion of the scaffold to the seed cells, and promote nerve regeneration and graft vascularization, in this example, substances that can promote cell adhesion, nerve regeneration, and graft vascularization can be added to the decellularized allogeneic nerve . The substance can be extracellular matrix (extracellular matrix, ECM), including collagen, aminoglycans, and glycoproteins; it can also be various growth factors.

In this example, when the patient's digital nerve defect is 2 cm, an allogeneic digital nerve of corresponding length can be taken as a scaffold for decellularization; when the patient's median nerve defect is 4 cm, a corresponding length of allogeneic median nerve can be taken for decellularization Treated as a scaffold; when the patient's sciatic nerve defect is 6 cm, the allogeneic sciatic nerve of the corresponding length can be decellularized as a scaffold.

The above detailed description is a specific description of a feasible embodiment of the utility model, but the embodiment is not intended to limit the patent scope of the utility model, and any equivalent implementation or change that does not depart from the spirit of the utility model shall be Included in the patent scope of the present utility model.

Claims (5)

1. Tissue-engineered peripheral nerve graft, characterized in that: it includes a decellularized allogeneic nerve scaffold (1) for connecting the two stumps of nerves and seed cells (2) with the function of promoting nerve regeneration. The decellularized allogeneic The nerve scaffold (1) is composed of multiple decellularized nerve basement membrane tubes (11), and the seed cells (2) are attached to the inner wall of the nerve basement membrane tube (11), or attached to the nerve basement membrane tube (11) The outer surface forms a complex with neuromimetic three-dimensional structure and biological activity. 2. The tissue-engineered peripheral nerve graft according to claim 1, characterized in that the decellularized nerve allogeneic scaffold (1) contains substances that can promote cell adhesion, nerve regeneration and graft vascularization. 3. The tissue-engineered peripheral nerve graft according to claim 1, characterized in that: the seed cells (2) are adult stem cells. 4. The tissue-engineered peripheral nerve graft according to claim 3, wherein said adult stem cells are bone marrow mesenchymal stem cells. 5. The tissue-engineered peripheral nerve graft according to claim 3, wherein said adult stem cells are fat stem cells.

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