Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Implantable prosthesis
Reexamination Certificate
1999-08-16
2002-03-26
Nguyen, Dinh X. (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Implantable prosthesis
C623S013170
Reexamination Certificate
active
06361562
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to biomaterials comprising an extirpated piece from Chondrichthyes, Osteichthyes or Cyclostomata. More specifically, the present invention relates to biomaterials that comprise the above extirpated piece and are applicable as various alternative organs and implant materials.
BACKGROUND OF THE INVENTION
It has been considered difficult to achieve a successful xenogeneic transplantation between different kinds of animal in view of major histocompatibility complex (MHC) which causes the rejection reaction in the transplantation.
OBJECTS AND SUMMARY OF THE INVENTION
The inventor of the present invention has found that although a primitive vertebrate including Chondrichthyes, Cyclostomata and a part of Osteichthyes has a gene encoding MHC, the primitive vertebrate is in a state of immunological tolerance as seen in an embryo of a higher animal. The difference between the primitive vertebrate and the higher animal may be explained as follows: the expression of MHC gene was induced by an increased blood pressure caused in response to the gravity during the second revolution of vertebrates in the evolutionary process (i.e. terrestrialization), thereby generating human leukocyte antigen (HLA) in the course of evolution. As a result, the rejection reaction can be caused in the xenogeneic transplantation.
The inventor also has found that a skin transplantation between sharks as well as between shark and Cyclostomata can be successfully carried out, which had been considered impossible for a long time. In addition, it is also possible to transplant various organs from sharks to mammals.
The sharks have a much lower blood pressure whereas the mammals have a higher one because the sharks, in which the gravity is offset by buoyancy, differ from the mammals in responding to the gravity. Various organs from the shark may be transplanted to the mammals without any need for angiorrhaphy.
A series of studies shows that a primitive vertebrate is composed of the proteins that are closely similar to fetal proteins of the mammals. Various tissues from the primitive vertebrate have been observed to smoothly replace the mammal's own tissues after transplantation.
In the case of human, a successful transplantation has been achieved only with allograft of organs between a recipient and a donor compatible with the recipient in histocompatibility antigen. According to the present invention, it is possible to use various tissues from the primitive vertebrate (e.g. viscus, nerve and cornea) for transplantation in human, so that an important contribution can be made to the progress of medical science.
The present application encompasses the following inventions:
(1) A biomaterial comprising an extirpated piece from a tissue selected from the group consisting of the cornea, muscle, tendon, cartilage, alimentary canal, liver, pancreas, spleen, kidney, heart, blood vessel, nerve and brain of Chondrichthyes, Osteichthyes or Cyclostomata;
(2) The biomaterial according to (1), wherein the extirpated piece is obtained from a tissue of Chondrichthyes or Osteichthyes;
(3) The biomaterial according to (1), wherein the extirpated piece is obtained from a tissue of Chondrichthyes;
(4) The biomaterial according to (1), which is transplanted into mammals; and
(5) The biomaterial according to (1), which is selected from the group consisting of an artificial cornea, an artificial muscle tissue, an artificial tendon, an artificial cartilage, an artificial alimentary canal tissue, an artificial liver tissue, an artificial pancreas tissue, an artificial spleen tissue, an artificial kidney tissue, an artificial heart tissue, an artificial blood vessel, an artificial nerve tissue and an artificial brain tissue.
DETAILED DESCRIPTION OF THE INVENTION
Fishes to be used for obtaining an extirpated piece for preparing the biomaterials of the present invention may be Chondrichthyes, Osteichthyes or Cyclostomata.
As Chondrichthyes, fishes belonging to Elasmobranchii such as sharks and rays are preferred. Among all, sharks are most preferred. Specific examples of sharks include Shirozame, Mustelus, Triakis (dochizame) and Heterodontus(nekozame). Specific examples of rays include Anacanthobatis, Dasyatis and Pristis.
The Osteichthyes includes fishes having an endoskeleton, at least a part of which is bony, and a skull coated with periosteum. Fishes belonging to the Osteichthyes are roughly divided into large fishes and small fishes. Specific examples of large Osteichthyes include tuna, bonito and sea bass. Specific examples of small Osteichthyes include salmons such as Shirozake; sea breams such as Pagrus and Oplegnathus; red snappers such as Beryx and Anomalops; flatfishes such as Limanda and Engyprosopon; Seriola(yellowtail and young yellowtail) or Clupea.
The Cyclostomata includes fishes belonging to Agnatha including Petromyzontiformes and Myxiniformes. Specific examples include Lampetra japonica, Myxine and Eptatretus.
The extirpated piece used for preparing the biomaterials of the present invention may be taken from the following tissues or organs of these fishes: cornea, muscle, tendon, cartilage, alimentary canal, liver, pancreas, spleen, kidney, heart, blood vessel, nerve and brain.
The cornea used for the present invention may be taken from one or both of eyes of the Chondrichthyes and Osteichthyes (small one), and transplanted to each eye of mammals. A muscle used for the present invention may be, for example, a dorsal muscle of the Chondrichthyes. A tendon used for the present invention may be, for example, a fin of the Chondrichthyes. A cartilage used for the present invention may be, for example, a vertebral cartilage of the Chondrichthyes or an intervertebral cartilage of the Osteichthyes (large one). As an alimentary canal used for the present invention, for example, a part from the stomach to intestine may be used. In the case of the liver, for example, a hepatic parenchymal tissue from the Chondrichthyes may be implanted into the mammal's liver including the human liver by incision. In the case of the pancreas, for example, the pancreas from the Chondrichthyes may be implanted into the mammal's spleen or pancreas by incision. In the case of the spleen, for example, the spleen from the Chondrichthyes or Osteichthyes may be implanted into the spleen of a patient affected with blood disease by incision. In the case of the kidneys, for example, one or both of the kidneys from the Chondrichthyes may be implanted into a mammal's renal parenchymal tissue by incision. In the case of the heart, the recipient's heart from which a damaged part has been removed may be covered and sewn with the heart, for example, from the large Osteichthyes or Chondrichthyes. In the case of a nerve or the brain, the spinal cord from the Cyclostomata or Chondrichthyes may be transplanted as an alternative to nerve, or the brain from the Chondrichthyes may be transplanted to mammals. As an alternative to a blood vessel, for example, the alimentary canal from the Chondrichthyes or Cyclostomata may be used, from which an inner epithelial mucosa has been removed and which is turned over before used.
These extirpated pieces from the Chondrichthyes, Osteichthyes and Cyclostomata are preferred because there is no blood group substance or major histocompatibility antigen (i.e. no antigenicity) in these extirpated pieces including the cornea, muscle, tendon, cartilage, alimentary canal, liver, pancreas, spleen, kidney, heart, blood vessel, nerve and brain.
The biomaterials of the present invention may be used as an artificial tissue or organ including an artificial cornea, an artificial muscle tissue, an artificial tendon, an artificial cartilage, an artificial alimentary canal tissue, an artificial liver tissue, an artificial pancreas tissue, an artificial spleen tissue, an artificial kidney tissue, an artificial heart tissue, an artificial blood vessel, an artificial nerve tissue and an artificial brain tissue.
The term “artificial tissue or organ” used here refers to a tissue or
Fish & Richardson P.C.
Nguyen Dinh X.
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