Method of Tissue Growth

Class 435--Subclass 283

Class 435--Subclass 284.

Tissue growth on a nutritive surface typically reaches a critical size where continued growth necessitates a blood supply for internal nutrient delivery and waste removal. In the absence of blood supply, the critical tissue size is approximately one cubic millimeter. Cancerous tissue routinely emit angiogenesis factors to encourage capillary ingrowth. No current method exists, in vitro, to completely support tissue with a vasculature over a long period of time.

Tissue grafted from one individual to another temporarily grows and functions if a high degree of immunocompatability is present and immunosuppressive agents are employed in the host. However, the best substitute for diseased and damaged tissue is an individual is similiar healthy tissue from that same individual. In cases where conditions for growth of certain tissues in that individual are not present, a tissue substitute must be found. Although artificial organs have made considerable developmental progress, serious problems of power supply, compactability, and biological interfacing remain. In certain cases, such as severe muscular dystrophy or leukemia, no substitute is found and the individual dies. A critical need exists whereby a remaining portion of healthy tissue may be operatively removed from an individual, grown to a larger size, and then operatively substituted back within the individual to replace similiar damaged tissue.

This invention addresses these needs.

FIG. 1 is a schematic diagram showing the major components of the tissue growth support system, utilizing a growth tissue with an arterial input and venous output.

FIG. 2 is a schematic diagram showing interconnection of the tube to vascularized tissue.

FIG. 3 is a schematic diagram showing interconnection of the tube to a mesentary supporting a growth tissue.

It is an object of the present invention to teach a method and a means by growing tissue outside of the body to a size in which its vasculature develops and is utilized for nutrient supply and waste removal.

It is an object of the present invention to teach a method and a means of growing tissue outside of the body by connecting tissue's existing vasculature to a tissue growth support system.

It is an object of the present invention to provide a method and a means for the growth of fetuses at any developmental stage.

Referring to FIG. 1, a temperature controlled, humidity controlled antiseptic chamber 2 with appropriate gas and fluid input and output lines houses the major system components. A base tissue 4, which may be a mesentary or other tissue containing an arterial input 6 and a venous output 8, is connected to a tube 10 forming a continuous closed fluid transport system. The growth tissue 12 is normally grafted onto the base tissue 4, as in FIG. 2, but may be directly connected to tube 10 if the growth tissue 12 already has developed an arterial and venous supply system, as in FIG. 3. The tube 10 contains a solution 14 capable of transporting oxygen and nutrient to the tissue 4 and the tissue 12 and transporting carbon dioxide and waste products away from the base tissue 4 and the growth tissue 12. A pump 16 unidirectionally propels the solution 14. The tube 10 is connected to a gaseous exchange membrane 18, in turn connected to a constant regulated oxygen supply 20 and to a waste gas output vent 22. The tube 10 is connected to a supply input port 24 and a waste output port 26. The tube 10 is connected to an exchange membrane 28 allowing diffusion of waste products into a specially mixed and circulated dialysate 30, from dialysate reservior 32. Dialysate 30 may also contain nutrients ans ions necessary for tissue growth for reverse diffusion through exchange membrane 28 into solution 14. Dialysate 30 and exchange membrane 28 additionally allow water and acidity balance within the system.

In operation, the entire system is made sterile through radiation produced by an ultraviolet lamp 34 or through infused antibiotics 36. Under antiseptic conditions, growth tissue 12 is grafted onto base tissue 4 or connected directly to tube 10. Immunosuppressive drugs 38 may be added to the fluid 14 to inhibit graft vs host reactions and host vs graft reactions. Angiogenic drugs 40 and tissue growth factor 42 may be added to the system to encourage tissue growth and the formation of vasculature. Nutrients 44 are continuously infused into the system through the input supply port 24. Nutrients may also be supplied through diffusion from the circulated dialysate 30. All environmental factors, including temperature, humidity, solution acidity, oxygen consumption, nutrient supply rate, and waste removal rate are adjusted to provide a homeostatic environment most conducive to tissue growth.

The transport solution 14 may be composed of blood, with the normal white cell and platelet count reduced.

Other advantages of the present invention will be readily apparent to those skilled in the art.