JP2001070436A - Collagen supporting body for forming vital vascular structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to maintain the strength as a vital vascular structure and to produce various kinds of cell growth factors, for example, nerve growth factors, etc., by entangling vital tissue with the circumference of a collagen supporting body, thereby forming the vital vascular structure. SOLUTION: The vital vascular structure is formed by entangling the vital tissue with the circumference of the collagen supporting body. At this time, the supporting body is formed to a coiled or tubular form and the vital vascular structure is a nerve sheath to join the cut nerve ends to each other. As a result, the strength as the lumen structure and the production of the growth factors are facilitated and the easy production of the nerve cells by inserting the supporting body into a nerve defect part is made possible. Since the supporting body is bioabsorptive, the need for extirpating the same again by operation, etc., is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a collagen support for forming a biological tract structure, which is a tissue forming a lumen in a living body. More specifically, the present invention relates to a collagen support for forming a biological tract structure by entanglement of a living tissue around a collagen support.

[0002]

2. Description of the Related Art Conventionally, blood vessels, ureters, trachea, nerve sheaths, etc.
Tissue substitutes that form a lumen in vivo and function by its structure have been made primarily of artificial materials. Of these, artificial blood vessels and artificial ureters that function in vivo as a tubular structure are used, and most of the materials used are urethane, Gore-tex, and other biocompatible synthetic polymers. It is configured. These materials have the drawback that they remain at the implantation site forever because they are biocompatible but not bioabsorbable. To improve this, artificial blood vessels and artificial ureters made of bioabsorbable polymers have been considered. On the other hand, an artificial nerve sheath, which requires a tubular structure for the purpose of regeneration in a lumen structure and its internal space, such as a nerve sheath, has been tried. Conventionally, techniques for joining surgically cut peripheral nerves have been developed. However, depending on the degree of nerve deficiency, tension is applied to the suturing portion, so that end end suturing becomes impossible and autologous nerve transplantation is required. In this case, there is a problem that a nerve deficiency symptom occurs at the site where the nerve for transplantation is collected, and the number, length and diameter of the nerves that can be collected are often limited.

On the other hand, as a basic concept of nerve regeneration, a technique of connecting both ends of a nerve using a tube has been considered for a long time, and various materials are used as a tube to secure a space for the nerve to extend. Nerve regeneration has been attempted. As a result, it has become clear that nerves can be rejoined even if the nerves have been severely cut so that they cannot be joined by surgery by securing space in the direction in which the nerve cells extend. The most common way to secure nerves and regenerate nerves in this way is to embed the tube, and attempts have been made to regenerate nerves using synthetic polymer tubes such as silicon, nitrocellulose, and Gore-Tex. Have been.
However, these tubes are non-absorbable and have low permeability to substances necessary for nerve cell elongation, which is a factor that hinders nerve regeneration, and nerves are regenerated because they are foreign substances in vivo. After that, he was forever in the body. Further, the tube needs to have a certain strength to maintain the space, and thus has poor flexibility, and the remaining tube may protrude from the body without being constantly stopped by movement such as bending. For this reason, re-operation for removing the remaining tube is necessary, but this may injure the nerve once regenerated by making an incision around the nerve.

In recent years, Lundborg et al. Placed a rigid silicon support in which a steel wire was wound in a coil shape in a living body to obtain a lumen material for bonding a nerve, and formed a living body tissue around the solid silicon support. A strut is obtained, taken out of the living body, and a silicon strut is taken out of the taken out material to form a tube made of a biological membrane. The tube of the biomembrane maintains a lumen structure due to the presence of a coiled steel wire. Attempts have been made to use this as a biological tube.
(Lundborg G et al Clinical application of biomate
rials Advances in Biomaterials 4 Vol. 179 p573-329 (1
982)). In other words, Lundborg et al. Reported that good nerve regeneration was obtained by using the living tube thus obtained as a material for securing space. in this case,
Although it has the advantage that it does not hinder the permeation of the substance in the tube due to its coil shape, it is not clinically practical because the steel wire is a foreign substance and stays in the locality forever.

[0005]

For this reason, nerve regeneration using a tube made of a bioabsorbable polymer has recently been attempted. As a tube-building material for maintaining a tube structure in a living body, such as an in-vivo tube structure such as an artificial blood vessel and an artificial ureter made of a bioabsorbable polymer and a tube for nerve regeneration, for example, collagen, polyglycolic acid ( PGA) is under study. These materials for constructing tubes made of these bioabsorbable polymers are rich in permeation, have the advantage that they do not need to be removed by reoperation because they are absorbed by the tube structure and the living body, and they do not destroy surrounding tissues because they are flexible. There are many. However, on the contrary, the flexibility reduces the strength of the tube construction material. In particular,
When a tube used for nerve regeneration is crushed by movement such as refraction, there is a problem that a space necessary for elongation of nerve cells cannot be secured.

[0006]

Means for Solving the Problems In view of the above problems, the present inventors have conducted studies, and as a result, have come to invent a collagen support for forming a tubular structure. That is, the present invention is a collagen support for forming a biological tract structure, wherein a biological tissue is entangled around the collagen support. In the present invention, collagen is used as a support, and the body tissue is entangled with the collagen to maintain the strength of the tubular structure of the support and to produce various cell growth factors such as nerve growth factor. is there.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below. Collagen used in the present invention may be insoluble or soluble, and soluble collagen is acid-soluble collagen,
Enzyme-soluble collagen, alkali-soluble collagen, salt-soluble collagen and the like are included. Alternatively, chemically modified collagen obtained by chemically modifying these may be used. The origin of collagen includes bovine, porcine, human and the like. In addition to the collagen extracted from the tissue, recombinant collagen obtained by gene transfer may be used. The collagen support of the present invention may have any shape as long as it can form a tubular structure, and examples thereof include sponges, tubes, and coils. The size of these shapes differs depending on the type of shape, the size of the defective part, the part to be inserted, and the like. For example, in the case of a sponge body, its thickness is 0.1
It is desirably about 2.0 mm. If it is too thin, the strength is low, and if it is too thick, it is difficult to form a tube structure. In the case of a tube, the diameter is about 1.5 to 5.0 mm,
If the tube wall is too thick, absorption will be slow, and if it is too thin, it will be difficult to maintain the shape of the tube. Desirable thickness is about 0.1 to 0.2 mm. In the case of a coil, it is usually formed by winding a collagen thread around a core body.If the diameter of the collagen thread is too small, it is difficult to provide a scaffold when entangled with tissue, and if it is too thick, absorption becomes slow. . The nozzle diameter when extruding the collagen thread is desirably about 0.5 to 3.0 mm.

Next, a method for producing a collagen support having these shapes will be described. When making a sponge body, a collagen aqueous solution and suspension are prepared. At this time, the collagen concentration is preferably 0.3 to 3.0%, and the pH is acidic.
Any neutral may be used. A sponge is prepared from this collagen aqueous solution or suspension. The method is not particularly limited, but for example, a sponge can be obtained by freeze-drying in a mold. When making tubes and coils, an aqueous collagen solution is prepared. The collagen concentration is 3 to 40%, preferably 10 to 30%. The aqueous collagen solution is extruded from a nozzle and formed into a desired shape. When forming a tube, a nozzle is selected so that the tube diameter becomes the diameter of the target tube structure, and the nozzle is extruded while the shaft is inserted into the inner diameter. At this time, if the tube wall is too thick, absorption becomes slow. Desirable thickness is about 0.1 to 0.2 mm. The material of the shaft is not particularly limited, but is preferably biocompatible because it is embedded in a living body in order to entangle a living tissue, and examples thereof include silicon and Teflon.

In the case of extrusion molding, when the collagen concentration is low, the fiber is extruded into a saturated salt solution such as sodium chloride or sodium sulfate to obtain a yarn. When the collagen concentration is sufficiently high, the extruded yarn can be dried as it is to obtain a yarn. Regardless of the shape, when the obtained molded product has an acidic pH, it is neutralized. Neutralization can be performed by ammonia gas neutralization, immersion in a phosphate buffer, or the like. When a coiled support is used, a neutralized collagen thread is wound around a shaft to obtain a coiled molded product. Like the tube, the material of the shaft is not particularly limited, but is preferably biocompatible. The obtained collagen molded product is fixed in its shape by crosslinking, and used as a collagen support. The crosslinking method is not particularly limited, such as physical crosslinking and chemical crosslinking. Examples of chemical crosslinking include glutaraldehyde, formaldehyde, isocyanate compounds,
An epoxy compound or the like can be used as a crosslinking agent.
As the physical crosslinking, photocrosslinking, thermal crosslinking, γ-ray crosslinking and the like are used. When a sponge is used as a support, the obtained sponge is wound around an axis, sutured with a surgical thread, and formed into a tube. The shaft at this time is desirably biocompatible, and the surgical thread is desirably absorbable.

[0010] The collagen support thus obtained is embedded in a living body while leaving a shaft, and a living tissue is entangled around the living body. That is, when a collagen support having a shaft is inserted into a living body, and the collagen support is taken out when the living tissue is sufficiently entangled, the collagen support having a tubular structure having sufficient strength can be obtained. Preferably, this is implanted in a target site of the same kind of living body, thereby forming an artificial blood vessel, an artificial ureter, or the like. Insertion of the end into the tube of the tube structure extends the nerve and achieves nerve regeneration.

[0011]

EXAMPLES The present invention is described below by way of examples, but the present invention is not limited to these examples. Example 1 A collagen aqueous solution (collagen concentration 30%, pH 3.0) was prepared using enzyme-solubilized collagen. This collagen solution is extruded from a nozzle (nozzle diameter 17G),
After drying, a collagen thread was obtained. The yarn was neutralized by placing it in a 0.1 M phosphate buffer (pH 7.4, containing 10% Na ₂ SO ₄ ). Wind the neutralized collagen thread around a Teflon shaft (shaft diameter 1.5 mm, shaft length 60 mm),
After immersing in a 1% glutaraldehyde aqueous solution for 1 hour to form a coil, the residual aldehyde was inactivated by glycine treatment to obtain a coiled collagen support.

Example 2 A collagen aqueous solution (collagen concentration 30%, pH 3.0) was prepared using enzyme-solubilized collagen. This collagen solution is extruded from a nozzle (nozzle diameter 17G),
After drying, a collagen thread was obtained. The yarn was neutralized by placing it in a 0.1 M phosphate buffer (pH 7.4, containing 10% Na ₂ SO ₄ ). Wind the neutralized collagen thread around a Teflon extraction (shaft diameter 1.0 mm, pongee length 40 mm), 10%
It was immersed in an aqueous formaldehyde solution for 3 hours and molded into a coil to obtain a collagen support.

Example 3 An aqueous collagen solution (collagen concentration 30%, pH 3.0) was prepared using enzyme-solubilized collagen. This collagen solution was extruded from a nozzle (nozzle diameter: 00 mm) around a silicon tube (outer diameter: 00 mm) to obtain a collagen tube. This tube was neutralized with ammonia and then immersed in a 0.5% hexamethylene diisocyanate / methanol solution for 3 hours to crosslink, thereby obtaining a tubular collagen support.

Example 4 An aqueous collagen solution (collagen concentration 0.5%, pH 3.0) was prepared using enzyme-solubilized collagen. This collagen solution was poured into a styrene tray of 10 × 10 cm so as to have a height of 1.0 mm, and freeze-dried to prepare a collagen sponge. This was neutralized with ammonia gas and crosslinked by dipping in a 0.5% hexamethylene diisocyanate / methanol solution for 3 hours. The sponge was wound around a silicon shaft having a shaft diameter of 3 mm and a shaft length of 50 mm, and sutured with a surgical thread to obtain a sponge-like collagen support.

Example 5 The left sciatic nerve of a rat was cut at the center of the thigh and both sections were inverted to inhibit spontaneous regeneration. Here, the coil-shaped molded product obtained in Example 2 was placed and closed. Four weeks later, the same part was incised again, and both nerve stumps were inserted into the lumen formed after removing the Teflon shaft so that the gap between the sciatic nerve stumps was 10 mm, and sutured. Observation four weeks later, it was observed that the nerve deficient part was cross-linked to a tissue having continuity, and blood vessel invasion was recognized in the cross section at the center of the tube.

Comparative Example A silicon tube (inner diameter 15 m) was prepared in the same manner as in Example 2.
m) was retained. Four weeks later, the nerve deficient part was filled with a yellow transparent liquid, but no tissue bridging between both ends of the nerve was observed.

[0017]

As described above, the present invention uses collagen, which is a bioabsorbable polymer, and entangles it with living tissue to facilitate the strength as a luminal structure and the production of growth factors. When inserted into a nerve defect, nerve cells can be easily produced, and furthermore, since it is bioabsorbable, it is not necessary to remove it again by surgery or the like.

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Claims (4)

[Claims] 1. A collagen support for forming a biological tract structure, wherein a biological tissue is entangled around the collagen support. 2. The collagen support according to claim 1, wherein said support is coil-shaped. 3. The collagen support according to claim 1, wherein said support is tubular. 4. The collagen support according to claim 1, wherein the biological tube structure is a nerve sheath for joining the cut nerve ends.