APPARATUS FOR INDUCING AN IMMUNE RESPONSE IN CANCER THERAPY

Abstract: Device for inducing an immune response in cancer therapy in which isolated living malignant tissue is enclosed in the space (10) formed by a microporous membrane (6) in a holder (1) which is introduced into a body cavity so that macromolecular and cellular immune system components can pass freely in both directions through the membrane (6) while malignant cells of the tumour tissue remain trapped inside.

Description: APPARATUS FOR INDUCING AN IMMUNE RESPONSE IN CANCER THERAPY FIELD OF THE INVENTION This invention relates to the use ofmicroporous membranes in which is enclosed isolated living malignant tissue for the purpose of inducing a strong immune response after introduction in a body cavity in the treatment of malignant tumours. The invention relates especially to the use of artificial membranes, which are not only compatible with the physiological environment in the body but enable the exchange of macromolecular and cellular components of the immune system in both directions without allowing the leakage of malignant cells into the blood and lymphatic circulation ( i.e. after introduction of the membrane with the isolated tissue into the body cavity in a suitable holder). DESCRIPTION OF THE PRIOR ART A very efficient method in the treatment of cancer is known under the term " devitalization ". The devitalization surgical technique has been described extensively in the literature not only in its application in model experiments using animals (Fortyn, K., et al. Z.exp.Chir.Transplant.kunstl. Organe. 18 :34-41, 1985 ; Fortyn, K. et al. Acta Chirargica Hungarica. 29 (2) :163-172, 1988) but also in clinical practice particularly in connection with tumour affections of the gastrointestinal tract (Fortyn, K., et al. Klinicka onkologie. 1 : 7-10, 1989). Devitalization is a surgical intervention which is aimed to interrupt all vascular supply, i.e. simultaneously the arterial flow and venous reflux in a delimited mass of tissue in the body. This stops blood circulation in the affected area, the filtration of serum from the capillaries is brought to a halt and the production of lymph ceases. The ensuing ischaemia affects nerve extremities in the tissue. The transmission of impulses is thus interrupted and the perception of pain in the devitalized site is relieved. The devascularized tissue is gradually resorbed and the process provokes an immune response by which metastases are eliminated. The critical physiological condition of the devitalization surgical intervention is that it does not lead to the immediate damaging of the integrity of the plasma membrane of cells in the affected tissue. There is no massive necrotic cytolysis typical for ischaemia which leads to the liberation of larger quantities of allergens that penetrate the tissue not only locally but may also enter the blood and lymphatic circulation. Ischaemia under such conditions normally causes undesirable inflammatory reactions but in extreme cases it may even provoke a fatal systemic shock. This is observed especially in various forms of directed embolization which must not be confused with devitalization. The physiological effect which is produced by devitalization differs from the effect of simple arterial obstruction in that ordinary embolization mainly leads to the interruption of the oxygen supply while other blood components can still penetrate the affected tissue by venous reflux. Because venous blood deprived of oxygen and saturated with carbon dioxide has a lower value pH a greater amount of calcium which is bound to proteins in the blood is liberated. The lowering of the energetic reserve of ATP in cells as a result of ischaemia disrupts the electric potential at the plasma membrane which is necessary for maintaining normal levels of the intracellular concentration of calcium. With the onset of ischaemia and by the continuing supply of nutrients from the venous reflux, calcium enters tissue cells in larger amounts and activates Ca 2+ dependent phospholipases. This leads to irreversible damage of the plasma membrane resulting in leakage and massive cellular lysis. In spite of the fact that devitalization involves a more consequent ischaemia, massive necrotic cytolysis is prevented because the affected tissue is not supplied with blood components that could provoke the disruption of the plasma membrane. Following devitalization, when venous reflux is arrested, the integrity of the plasma membrane is preserved not only in healthy cells but also in the malignant cells of the affected tissue. The determining circumstance for devitalization to exert its therapeutical effect is the high degree of ischaemia and the lack of growth factors which are two important physiological conditions necessary for immune system triggering of apoptosis or programmed cellular death. In such an environment, cellular distress and immune system signals are generated by leucocytes and lymphocytes present in the tissue prior to devitalization. On the other hand, in the case of simple embolization, apoptosis is not likely to occur because the depletion of growth factors and an increasing concentration of intracellular calcium which act in opposition will inhibit the mechanisms normally responsible for its triggering. When apoptosis or programmed cellular death is initiated, cellular disintegration is progressive and is genetically controlled in such a way that it does not lead to the liberation of larger amounts of allergens either locally or into the general circulation. Devitalization, therefore, does not provoke an inflammatory reaction which in acute cases may create an adverse physiological environment linked with the risk of necrotic infection. Apoptosis normally leads to the fragmentation of cellular components and these are progressively phagocytised by competent leucocytes especially macrophages. The affected cellular mass is gradually degraded to simple components by specific enzymes and this contributes to the positive stimulation of the entire immune system. Simultaneously antigens liberated from malignant cells under these conditions begin to be recognized as non-self and the immune system is mobilized to destroy malignancies in the whole body. The activity is due not only to leucocytes and lymphocytes which infiltrate the affected area under the effect of chemotaxis but also those which are present in the tissue prior to the devitalization intervention. In principle, devitalization as a surgical technique in which devascularized or completely isolated malignant tissue is left in the body can be applied in the treatment of all types of solid tumours in most organs of the body. A certain exception are soft and highly vascularized tisues and those which are surgically inaccessible. A typical example is brain tissue. Another major disadvantage of the standard devitalization technique is the fact that its application is indicated especially in cases where the tumour affection was diagnosed too late to expect complete remission following either radical surgery or any other type of treatment. These are mostly situations when there is important invasion of the malignancy into surrounding tissues, lymph nodes and even other organs. This means that after the devitalization intervention the possible secondary dissemination of malignant cells does not represent any new potential danger for the patient. In this connection, it is therefore necessary to consider the possibility of an eventual slower immune response if the intervention is carried out at an earlier stage of the tumour affection when it is not possible to predict the reaction of the organism. In such a case, a larger mass of isolated malignant tissue left in a body cavity can be linked with the risk of a more important dissemination of malignant cells even before the immune system is fully mobilized to react and with no possibility of clinically monitoring the progress of the intervention and interrupting it without serious consequences should there be any anomalous behaviour. DESCRIPTION OF THE INVENTION The limitations and disadvantages of the standard devitalization surgical technique are for the greater part eliminated by the present invention according to which isolated living malignant tissue, before being introduced into a body cavity, is enclosed in a form of sheath the external part of which is delimited by a microporous membrane. The porous material allows the passage of all molecular and cellular components of the immune system in both directions but not the leakage of malignant cells into the external environment. The device according to this invention is thus open to all processes and physiological mechanisms which are normally induced by the standard devitalization technique but does not allow the secondary dissemination of malignant cells particularly in the case of the devitalization of soft tissues. When using the device according to the present invention malignant tissue can be taken from any part of the body and introduced into any body cavity. The sheath which encloses the isolated malignant tissue can easily be removed from the body in case of clinical necessity. The device according to the invention allows the systematic sampling of disintegrating tissue material in the course of therapy as well as any type of continuous remote monitoring of physiological parameters. By placing microelectrodes inside the sheath it is possible to monitor temperature, pH, redox potential, pO 2 and pCO 2 levels. Similarly, with the use of specific bioelectrodes it is possible to monitor continuously the levels of substances linked with the ongoing biological process. The device acccording to the invention is therefore suitable for research purposes. The sheath or holder of the device according to the present invention can be constructed in the form of a cylinder, ellipsoid, annulus, or any shape which will assure good harmless anatomical contact of the microporous material with surrounding tissues in the body cavity. The most suitable shape is typical for endoscopic instruments and allows easy introduction through a small opening in the body. An opening in the holder allows the introduction of biological material. It can be closed by a bayonet, screw, watch type fitting or any other suitable mechanism. According to the form of execution the holder is provided with openings for the introduction of hollow sampling needles or the fixation of microelectrodes. In the construction of the holder it is necessary to use suitable materials which are biologically safe and do not provoke undesirable immune reactions. The holder can be made of all materials which are used successfully in orthopaedic surgery in the various types of prostheses. Such materials are found among stainless steels with a higher content of cobalt, titanium, or metals otherwise used in medicine such as platinum, palladium, gold and other precious metals of group Nπi of the periodic system and their alloys. Suitable construction materials are also to be found among plastics based on polyamide, polycarbonate, polyurethane , teflon as well as many others used in surgery (e.g. material used in the fabrication of artificial heart valves). The next integral part of the device according to the present invention is the microporous membrane. Products generated by the disintegrating and decomposing devitalized tissue leak out through the microporous membrane filter while macromolecular and cellular components of the immune system pass both in and out. The size of the pores of the membrane fabric is so chosen that leucocytes or lymphocytes which can squeeze through interstices smaller than the normal size of such cells can pass freely whereas tissue cells, which cannot change their shape adequately, remain trapped inside the membrane space. For this reason the size of the pores is critical. It should be larger than 2 microns but not larger than the mean size of the tissue cells which are introduced into the device. The material from which the membranes are made must meet the same conditions of compatibility with the physiological environment in the body as the material of the holder. Such membrane filters are best made from all types of suitably adapted materials used for sterile filtration of liquids in pharmaceutical and medical practice (e.g. Millipore, Ultrapore, Sefar, Pall-Gelman and other industrially manufactured membrane filters). For example, hydrophilic polyamide Nylaflo Pall-Gelman type belongs to the more suitable materials. The device according to the present invention is described in more detail in the drawings which picture two typical executions. Figure 1 describes an universal endoscopic type of device, which is particularly suitable for research. Figure 2 describes the simplest type of device, which is suitable for routine clinical application. Before use the device is sterilized, preferably by gamma irradiation. In both types of the above mentioned devices according to the present invention the isolated living tissue is introduced into the membrane space which is then filled with sterile physiological solution and the holder is immediately closed with the corresponding fitting. The forward part of the device according to Figure 1 is then surgically introduced through a small opening into the body cavity. The back part of the device which has no membrane surface and can eventually be extented by a flexible tube is fixed securely on the body. The device is maintained in the body cavity either for a limited observation period or for the whole duration of the therapeutical intervention. In the case of the device according to Figure 2 the procedure is the same as above, except that the whole assembly is introduced into the body by a more invasive operation. It is fixed in a suitable position on the internal wall by stitching to obtain optimal anatomical contact with the membrane part of the holder and without causing any important spatial hindrance in the body cavity. The device is surgicallly removed from the body at the end of the intervention according to clinical indications. EXAMPLES OF THE INVENTION Example 1. The device according to Figure 1 consists of a tubulal holder 1 and a cylindrical membrane assembly 2 . The front part of the main tubular casing is provided with lamellar openings 3. A sliding tube 4 which is tightly mounted on the main tubular casing has a knife edge at the front extremity which serves to remove fibrous overgrowth on the surface of the membrane during a clinical intervention. The length of the sliding tube 4 is adapted to allow the removal of fibrous deposit along the whole surface of the membrane filter 6 . The cylindrcal membrane assembly 2 is slipped on the front part of the main casing when the head is removed. The internal surface of the membrane assembly consists of a supporting netting 5 made of either metal or plastic fibre eventually out of perforated material. The supporting part is covered with the finer microporous material 6 and both are welded together at the extremities on a ring which fits tightly on the tubular casing 1 . The cylindrical membrane assembly 2 is fixed in position by means of the removable head 7 which closes the opening for the introduction of biological material. The head is appropriately rounded to assure safe penetration in the body cavity. The rear cap 8 is provided with openings 9 for electrodes and sampling needles. Example 2. The device according to Figure 2 consists of two flat rings which together form a clamping holder 1 for the covering netting 5 and the microporous membrane 6 . This assembly creates the internal space 10 in which is introduced the isolated tissue to be devitalized. One of the clamping rings is provided with a grove 11 for fitting an O-ring seal. The holder rings are provided with either a ridge or a grove near the external circumference 12 for the purpose of clamping. One of the holder rings is provided with eyehole loops along the circumference for fixing the device on the internal wall of the body cavity.

Claims: PATENT CLAIMS 1. A device for inducing an immune response against malignant cells and tumours in cancer therapy, wherein isolated living malignant tissue is enclosed in a space formed by a microporous membrane inside a holder which is introduced either partially or integrally into a body cavity. 2. A device according to claim 1, wherein the pores of the membrane (6) are larger than 2 microns but smaller than the mean size of the cells of the biological tissue which is enclosed in the holder (1). 3. A device according to claims 1 and 2 , wherein the membrane (6) is made from hydrophilic plastic material compatible with the physiological environment in the body cavity. 4. A device according to claims 1 - 3 incl., wherein the holder (1) has the form of an endoscopic tube which is introduced into the body cavity for a defined period and then removed without the need of a more important surgical intervention. 5. A device according to claims 1 - 4 incl. , wherein the holder (1) is provided with openings (9) for sampling needles and electrodes. 6. A device according to claims 1 - 5 incl. , wherein the holder (1) is provided with a flexible extension for integral introduction into the body on the principle of an endoscope.

Inventors: HORAK VRATISLAV, KALINA VLADIMIR, RICHTER PAVEL, HORAK, VRATISLAV, KALINA, VLADIMIR, RICHTER, PAVEL
Applicants: HORAK VRATISLAV, KALINA VLADIMIR, RICHTER PAVEL, HORAK, VRATISLAV, KALINA, VLADIMIR, RICHTER, PAVEL
Application year: 2001
Main classification: A61M31
IPC codes: A61F2, A61M31, A61M37