JP2003299731A - Removing system of harmful substance-binding albumin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an extracorporeal circulation system for treating chronic or acute pneumonia and liver diseases such as liver failure, which can effectively remove low or medium molecular weight substances, mediators such as cytokines or harmful substance-binding albumin such as bilirubin-binding albumin and can correct water and electrolyte balances without consuming expensive plasma heavily. <P>SOLUTION: The removing system of harmful substance-binding albumin for an extracorporeal circulation treatment comprises the following means: (1) a means for supplying the body fluid containing the harmful substance- binding albumin to a harmful substance-binding albumin remover capable of removing the harmful substance-binding albumin while leaving the high molecular weight proteins; (2) a means for removing the harmful substance-binding albumin from the body fluid using the harmful substance-binding albumin remover; and (3) a means for supplying albumin to the body fluid cleared of harmful substance-binding albumin. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a toxic substance binding for continuously and efficiently removing toxic substances in blood from blood of patients with liver diseases such as chronic or acute hepatitis and liver failure by extracorporeal circulation. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an albumin removal system and a method for removing harmful substance-bound albumin by the harmful substance-bound albumin removal system.

[0002]

2. Description of the Prior Art For the treatment of liver diseases such as chronic or acute hepatitis and liver failure, removal of medium to low molecular weight harmful substances in blood,
Water, correction of electrolyte balance, removal of mediators such as cytokines, removal of albumin-bound albumin bound to harmful substances such as bilirubin, and supplementation of protein coagulation factors such as blood coagulation factors and albumin are performed. Plasma exchange therapy, continuous hemofiltration therapy (CH
F), continuous hemofiltration and dialysis therapy (CHDF), adsorption therapy, and other extracorporeal circulation treatment methods have been implemented, and various extracorporeal circulation systems have been put to practical use.

[0003] Continuous hemofiltration therapy (CHF) and continuous hemofiltration dialysis therapy (CHDF) have excellent ability to remove medium and low molecular weight substances having a molecular weight of 10,000 to 20,000 daltons and are used for the purpose of removing these substances. ing. Recently, CHF and CHDF using a membrane capable of removing a substance having a molecular weight of about 30,000 daltons have been carried out for the purpose of removing mediators such as cytokines. However, the membranes used in these treatments do not allow albumin to pass through, and thus CHF and CHDF barely remove harmful substance-bound albumin.

In plasma exchange therapy, plasma of a patient is separated and discarded using a plasma separation membrane, and then fresh plasma is administered to remove mediators such as cytokines, albumin bound to harmful substances, blood coagulation factors, and the like. It is intended to assist liver function such as protein synthesis such as supplementation of albumin. Although plasma exchange therapy is excellent in removing harmful substance-bound albumin, it requires a large amount of fresh plasma. Therefore, a large amount of fresh plasma is also replaced to support liver function, and thus a large amount of fresh plasma is required. However, there is a problem that a large amount of expensive plasma is required. Furthermore, it has a drawback that the removal of substances having a molecular weight of 10,000 or less is insufficient.

Further, for the purpose of removing medium to low molecular weight substances and mediators such as cytokines, it is also known to use an adsorbent composed of, for example, a styrene / divinylbenzene copolymer, and petroleum pitch-based activated carbon. However, although the adsorbent is suitable for removing a limited type of substances, it is insufficient for removing a wide range of medium and low molecular weight substances, and also has insufficient ability for removing mediators and albumin bound to harmful substances. Furthermore, it is not possible to correct the water / electrolyte balance.

As a technique focusing on the ability of albumin to adsorb harmful substances, the Molecular Adsorbents Recircu
lating System: MARS, Teraklin) has been reported (Artificial Organs. 23 (4): 319-330, 1999). The mechanism of action of MARS is explained as follows. That is, in a device such as a dialyzer (artificial kidney) in which blood and dialysate are in contact with each other through a membrane, a large amount of albumin is present on the dialysate side, and the harmful substance-adsorbed albumin in blood that is in contact through the membrane is Only the released harmful substance is moved through the membrane by the principle of adsorption equilibrium and concentration gradient, and re-adsorbed to albumin on the dialysate side, and as a result, the amount of harmful substance in blood is reduced. In this method, of the harmful substances adsorbed to albumin in blood, only those that are released at adsorption equilibrium, permeate through the membrane, and adsorb to albumin in the dialysate will be removed. Is not good.

Japanese Patent Publication No. 9-507414 describes that a hollow fiber membrane and an adsorbent are used to remove protein-binding and medium molecular weight toxins. Plasma filtration (plasma is filtered through a membrane) or hemofiltration (medium molecular weight molecules (about 30
It is intended to adsorb and remove protein-bound and medium molecular weight toxins by contacting the body fluid obtained by filtration) (molecular weight of 0 to about 10,000) with an adsorbent outside the hollow fiber. The hollow fiber membrane used here is capable of filtering plasma or molecules having a medium molecular weight (molecular weight of about 300 to about 10,000), and both plasma separation membranes and dialysis membranes can be used. For example, Plasmaflo AP-05H (cutoff molecular weight approx.
1,000,000) and copper ammonium cellulose dialysis membrane are exemplified. However, Japanese Patent Publication No. 9-507414 discloses an attempt to bind a toxin bound to a protein to the adsorbent by a competitive reaction between the protein and the adsorbent. Toxins that bind strongly to proteins and are extremely difficult to dissociate are not substantially bound to the adsorbent and are not removed. Therefore, there is no difference in that the separated plasma is brought into contact with the adsorbent after the plasma is separated, as compared with the conventional method in which the separated plasma is perfused in the container filled with the adsorbent. Also, to perfuse the adsorbent,
There is also the possibility that the pump will damage the adsorbent.

In the present invention, the harmful substances strongly bound to albumin are to be removed together with albumin, and the loss of proteins other than albumin is minimized when the harmful substances bound to albumin are removed. It is intended to utilize a membrane having a very limited albumin permeability. As described above, extracorporeal circulation and perfusion therapy such as plasma exchange therapy, CHF, CHDF, or adsorption therapy has been put into practical use for the purpose of treating liver diseases such as hepatitis and liver failure. But,
In any of these methods, there is still no excellent treatment system for removal of medium and low molecular weight substances, correction of water and electrolyte balance, removal of mediators such as cytokines, removal of harmful substance-bound albumin, and treatment methods have also been put to practical use. Not not.

[0009]

DISCLOSURE OF THE INVENTION The present inventors have aimed to treat liver diseases such as chronic or acute hepatitis and liver failure by removing medium and low molecular weight substances, correcting water, electrolyte balance, cytokines and the like. It is intended to provide an extracorporeal circulatory perfusion treatment system which is excellent in removing mediators, removing albumin bound to harmful substances such as bilirubin bound to albumin, and does not consume a large amount of expensive plasma.

[0010]

A toxic substance-bound albumin removing system for extracorporeal circulation and perfusion therapy, characterized by comprising the following means. 1) A means for supplying a body fluid containing harmful substance-bound albumin to a harmful substance-bound albumin remover that removes the harmful substance-bound albumin and leaves a high molecular weight protein. 2) Harmful from the body fluid by the harmful substance-bound albumin remover. Means for removing substance-bound albumin 3) Means for supplying albumin to body fluid from which harmful substance-bound albumin has been removed and a method for removing harmful substance-bound albumin using the above-mentioned harmful substance-bound albumin removal system.

[0011]

DETAILED DESCRIPTION OF THE INVENTION

(Toxic substance-bound albumin) The low and medium molecular weight harmful substances referred to in the present invention include acute or chronic hepatitis,
A compound having a molecular weight of about 20,000 to 30,000 daltons or less that is found in blood such as liver failure and may adversely affect the liver and the like. Medium to low molecular weight harmful substances include ammonia, uric acid, creatinine, urea, uremic toxins, hydrophobic amino acids, bilirubin, bile acids, pesticides or herbicides such as paraquat, barbital and non-barbital hypnotics, coma etc. It can be illustrated. The term "hazardous substance-bound albumin" used in the present invention refers to albumin to which the medium-to-low molecular weight hazardous substance is bound, and examples thereof include hydrophobic amino acid-bound albumin, bilirubin-bound albumin, and paraquat-bound albumin.

(Toxin-bound albumin removal system)
The harmful substance-bound albumin system is a means for supplying an anticoagulant to a body fluid such as blood or plasma containing a harmful substance-bound albumin obtained from a patient with liver disease such as chronic or acute hepatitis and liver failure, and mixing the harmful substance-bound albumin. Means for supplying body fluid containing albumin to harmful substance-bound albumin remover, means for removing harmful substance-bound albumin and leaving high molecular weight proteins, supplying albumin to body fluid from which harmful substance-bound albumin has been removed The means for doing so are provided in this order.

The means for supplying and mixing the anticoagulant with the body fluid in the present invention means the circulation circuit of the body fluid from the supply circuit using the peristaltic pump or the syringe pump for the anticoagulant solution stored in the bag or syringe. Is a means for supplying a constant flow rate to. The supply method may be continuous or intermittent. The means for supplying the body fluid containing the harmful substance-bound albumin to the harmful substance-bound albumin remover is a means for supplying the body fluid to the remover at a constant flow rate to perform extracorporeal circulation, and a blood pump typified by a roller pump is preferable. Used. Further, as a means for removing harmful substance-bound albumin by removing harmful substance-bound albumin and leaving a high molecular weight protein, a substance having selective separation property for a substance to be removed, for example, an adsorbent or a separation membrane is incorporated. A remover is used. Further, as a means for supplying albumin to the body fluid from which the harmful substance-bound albumin has been removed, an albumin solution of a predetermined concentration stored in a bag or the like is used at a constant flow rate from the supply circuit to the circulation circuit of the body fluid using a peristaltic pump or a syringe pump. It is a means of supplying. Here, means for mixing a certain amount of citric acid and / or anticoagulants such as ethylenediaminetetraacetic acid, heparin, and nafamostat mesylate into a body fluid containing albumin containing harmful substances by a peristaltic pump, syringe pump, etc. It is desirable to have it before the means for supplying the albumin remover or after the means for supplying the harmful substance-bound albumin and before the harmful substance-bound albumin remover. The harmful substance-bound albumin removing system in the present invention may be used in the form of separating the harmful substance-bound albumin from blood by filtration or in the form of filtration dialysis.

First, the plasma separation method will be described. When whole blood is treated with a membrane that satisfies the performance of the present invention, a substantial part of high molecular weight proteins such as fibrinogen remains in the blood and is returned to the body. However, the medium and low molecular weight harmful substances such as ammonia and the harmful substances adsorbed on albumin permeate the membrane according to the present invention and are discharged to the outside of blood.
Since the inhibition rate of fibrinogen is often not 100%, a high molecular weight protein is slightly excreted out of the blood. That is, in the system of the plasma separation form according to the present invention, compared with the blood in the body, the plasma to be discarded contains a large amount of albumin bound with harmful substances and lower medium- and low-molecular-weight substances less than that, and high levels of fibrinogen and the like. There are few molecular weight substances. The high molecular weight protein slightly lost from blood can be supplemented by injecting a blood product such as frozen fresh plasma or albumin. The amount of frozen fresh plasma or the like required in the present invention may be extremely small and does not require a large amount of expensive plasma unlike the plasmapheresis treatment method. Furthermore, not only albumin bound to harmful substances, but also harmful substances to be removed may be present in the high molecular weight, so that a therapeutic system superior to CHF and CHDF can be provided. Next, the use form of filtration dialysis will be described. Continuous slow filtration dialysis (CHDF) performed slowly for about 8 to 24 hours or filtration dialysis (HDF) performed for several hours may be used. As the dialysis solution, it is possible to use a dialysis solution or the like used for ordinary artificial dialysis. Since the medium-low molecular weight substance can be efficiently removed by dialysis, the use form of filtration dialysis is more preferable than the plasma separation method in that the medium-low molecular weight substance can be efficiently removed simultaneously with the harmful substance-bound albumin.

(Toxic substance-bound albumin remover) The means for removing the harmful substance-bound albumin by the harmful substance-bound albumin remover is to remove the harmful substance-bound albumin and the medium and low molecular weight substances, and leave the high molecular weight proteins. is necessary. At the same time, when removing the harmful substance-bound albumin, it is more preferable that water and an electrolyte are simultaneously supplied. For the harmful substance-bound albumin remover, a membrane that allows albumin to pass therethrough, or a combination of an adsorbent for the harmful substance-bound albumin and an adsorbent for the medium and low molecular weight substances can be used. However, it is preferable to carry out filtration or dialysis with a membrane because the harmful substance-bound albumin and the medium and low molecular weight substances can be easily removed by a simple system. Furthermore, the method by dialysis using a hollow fiber membrane is most preferable because it can easily adjust water / electrolyte and can obtain an excellent ability to remove a medium to low molecular weight substance without increasing the removal amount of protein. Illustrating the most preferable harmful substance-bound albumin remover, a space having at least an inlet and an outlet for body fluid and an outlet for the harmful substance-bound albumin, and a space communicating with the inlet and outlet for the body fluid, and an outlet for the harmful substance-bound albumin The communicating space is divided by a porous membrane. The harmful substance-bound albumin remover is preferably sterilized by a method such as radiation sterilization with γ rays or electron rays, autoclave sterilization, gas sterilization, or the like.

(Membrane for removing harmful substance-bound albumin)
As the membrane used in the harmful substance-bound albumin remover, either a flat membrane or a hollow fiber membrane can be used, but a hollow fiber membrane is preferable from the viewpoint that a larger surface area can be secured in a limited volume. The membrane's fractionation ability is such that albumin sieving coefficient is 0.05 because it can remove albumin bound to harmful substances.
It is necessary to be above. Further, if the sieving coefficient of albumin is too high, the loss of protein becomes large and it becomes necessary to supply a larger amount of albumin preparation, which is not preferable. The albumin sieving coefficient is preferably 0.8 or less, more preferably 0.6 or less. Most preferably, a certain amount of albumin bound to harmful substances can be stably removed during extracorporeal circulation while maintaining the ability to remove medium and low molecular weight substances and the ability to adjust water and electrolytes, and to keep the total protein loss small. From the point of view, albumin sieving coefficient is 0.1 or more and 0.4 or less.

The filtration of proteins of higher molecular weight than albumin, eg fibrinogen, is therapeutically undesirable. A preferable membrane should have a sieving coefficient of fibrinogen of 0.6 or less, and the smaller the smaller, the more preferable. Most preferably, it is 0.1 or less. The fibrinogen listed here (molecular weight 340 kDa) is
It is considered that it can be an index of membrane performance in a group of proteins that are considered to have been lost more than necessary in the conventional mass plasmapheresis method. Besides fibrinogen, von Willebrand fac
Tor (1,000 kDa), Factor VIII (1,200 kDa), high molecular weight kininogen (110 kDa), Factor XI (160 kDa), Factor XIII fibrin stabilizing factor (320 kDa), etc. can also be used as an index. However, the figure of the blocking rate changes slightly depending on which index is used. Examples of the membrane material include polysulfone, ethylene vinyl alcohol, cellulose diacetate, cellulose triacetate, polyacrylonitrile, and the like, and any material having a preferable albumin sieving coefficient and stable to sterilization can be used. However, the present invention is not limited to these.

(Method of supplying albumin) It is necessary to supplement albumin with the removal of harmful substance-bound albumin. The albumin to be supplemented is preferably albumin preparation because it is easily available. Albumin is
It can be obtained in solution or in lyophilized form, but when replenishing it in the body, it should be in solution. Human albumin is preferable in consideration of immunogenicity and the like. Formulated albumin is obtained at the same time as separation of components other than albumin from plasma, and thus is considerably cheaper than frozen fresh plasma. further,
In recent years, a method for mass-producing human albumin by genetic engineering has been developed and is in the process of being put into practical use. Therefore, albumin may be cheaper by the time this formulation is commercialized. Of course, it is also possible to extract and use albumin from human blood at the treatment site. The supply of albumin is based on the amount of harmful substance-bound albumin removed.
It suffices that the therapeutically necessary amount can be supplied, and it may be supplied continuously or intermittently. Examples of the supply method include a method of continuously or intermittently adding / mixing an albumin solution from a replenishment circuit to body fluid that has passed through the harmful substance-bound albumin remover, and removal of the harmful substance-bound albumin by the harmful substance-bound albumin remover. At that time, a method of dialysis using a solution in which albumin is dissolved in a physiological electrolyte solution such as a dialysate can be mentioned. Alternatively, it may be separately or continuously supplemented into the body.

(Action) From the body fluids of liver diseases such as chronic or acute hepatitis and liver failure, harmful substance-bound albumin, mediators such as medium and low molecular weight substances and cytokines can be easily and efficiently removed, and water Thus, it is possible to provide an excellent extracorporeal circulation irrigation system capable of correcting the electrolyte balance.

[0021]

Example 1 A CHDF blood circulation system was constructed as shown in FIG. 1 by using Cascade Flow EC20W (manufactured by Asahi Medical Co., Ltd.) as the harmful substance-bound albumin remover 6. This remover is designed for use with ethylene with an inner diameter of 175 μm and a thickness of 40 μm.
It contains a hollow fiber membrane made of a vinyl alcohol copolymer and has an effective membrane area of 2.0 m ² .

Bovine blood containing bilirubin-bound albumin was prepared as a model blood containing harmful substance-bound albumin. That is, after dissolving bilirubin in a bovine albumin solution at a high pH in advance, a solution having a neutral pH was prepared by adding heparin (Novo heparin, 1000 units of heparin in 1 ml of this heparin. Novo Nordisk A / S) ) Was added to bovine whole blood containing 5 units / ml, and bovine whole blood having a total bilirubin concentration of 15.7 mg / dL was used as a model blood. 4 L of the model blood was pooled in the blood reservoir 1 and circulated by the blood pump 2 at a flow rate of 100 ml / min for 12 hours. At the same time, a physiological saline solution of heparin (same as above) was continuously supplied from the remover inlet side circuit 7 at a rate of 500 units / hour using the syringe pump 3. As the dialysate 9, Subrad-B (manufactured by Fuso Pharmaceutical Co., Ltd.) was used. The dialysate supply pump 4 had a flow rate of 500 ml / hour, and the dialysate drainage pump 5 had a flow rate of 80.
It was set to 0 ml / hour. That is, the amount of slow water from the remover is 3
It was set to 00 ml / hour. The albumin was supplied by dissolving a 20% human albumin preparation (manufactured by Japan Red Cross Co., Ltd.) in Subrad-B to a concentration of 1.38 mg / dL as albumin replacement fluid 10, and flowing into the remover outlet side circuit 8 at a flow rate of 300 m.
Feeded at 1 / h. Total bilirubin concentration, which is a harmful substance,
The albumin concentration was measured for plasma obtained by collecting whole blood from the blood reservoir 1 with time and centrifuging.
The total bilirubin concentration was measured by the alkaline azobilirubin method using Bilirubin BII Test Wako (manufactured by Wako Pure Chemical Industries, Ltd.), and the albumin concentration was measured by the BCG method using Albumin B Test Wako (manufactured by Wako Pure Chemical Industries, Ltd.). The sampling time was set to before the start of circulation (0 hour), and 6 hours and 12 hours after circulation.

Before the start of circulation (0 hour), the total bilirubin concentration in blood was 15.7 mg / dL and the albumin concentration was 4.6 mg / dL. The total bilirubin concentration in the blood at 6 hours of circulation decreased to 9.99 mg / dL, but the albumin concentration was 4.5 mg / dL, and the original concentration was maintained. Furthermore, the total bilirubin concentration in blood decreased to 8.96 mg / dL at 12 hours after the circulation, which was almost half that before the start, but the albumin concentration was 4.6 mg.
/ DL, and the original concentration was maintained.

[0024]

INDUSTRIAL APPLICABILITY The extracorporeal circulation system of the present invention is excellent in removal of medium and low molecular weight substances, correction of water and electrolyte balance, removal of mediators such as cytokines, and removal of albumin bound with harmful substances such as bilirubin bound to albumin. It is an extracorporeal circulation and perfusion treatment system that does not consume a large amount of expensive plasma, and can be effectively used for treatment of chronic or acute liver diseases such as hepatitis and liver failure.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a first embodiment.

[Explanation of symbols] 1. Blood pool 2. Blood pump 3. Syringe pump 4. Dialysate supply pump 5. Dialysate drainage pump 6. Remover of albumin bound to harmful substances 7. Removal device input side circuit 8. Remover output side circuit 9. Dialysate 10. Albumin solution

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Claims (10)

[Claims] 1. A toxic substance-bound albumin removal system for extracorporeal circulation therapy comprising the following means. 1) A means for supplying a body fluid containing harmful substance-bound albumin to a harmful substance-bound albumin remover that removes the harmful substance-bound albumin and leaves a high molecular weight protein. 2) Harmful from the body fluid by the harmful substance-bound albumin remover. Means for removing substance-bound albumin 3) Means for supplying albumin to body fluid from which harmful substance-bound albumin has been removed 2. The harmful substance-bound albumin removal system according to claim 1, further comprising means for supplying water and an electrolyte to the harmful substance-bound albumin remover. 3. The harmful substance-bound albumin removing system according to claim 1 or 2, wherein the harmful substance-bound albumin remover removes the low-molecular-weight substance together with the harmful substance-bound albumin at the same time. 4. The harmful substance-bound albumin remover has at least an inlet and an outlet for body fluid and an outlet for the bound harmful substance albumin, and the inlet and outlet for the body fluid and the outlet for the harmful substance-bound albumin are porous. The hazardous substance-bound albumin removal system according to any one of claims 1 to 3, wherein the system is divided by the membrane of 5. The harmful substance-bound albumin according to any one of claims 1 to 4, wherein the harmful substance-bound albumin remover comprises a hollow fiber membrane having an albumin sieving coefficient of 0.05 or more and 0.8 or less. Removal system 6. A method for removing harmful substances in blood for the treatment of extracorporeal circulation, which comprises the following means. 1) A means for supplying a body fluid containing harmful substance-bound albumin to a harmful substance-bound albumin remover that removes the harmful substance-bound albumin and leaves a high molecular weight protein. 2) Harmful from the body fluid by the harmful substance-bound albumin remover. Means for removing substance-bound albumin 3) Means for supplying albumin to body fluid from which harmful substance-bound albumin has been removed 7. The liver according to claim 6, wherein when the harmful substance-bound albumin is removed by the harmful substance-bound albumin remover, water and an electrolyte are simultaneously supplied to the harmful substance-bound albumin remover. How to remove toxic substances. 8. The method for removing toxic substances in blood according to claim 6 or 7, wherein the toxic substance-bound albumin remover removes the medium- and low-molecular weight substances together with the toxic substance-bound albumin at the same time. 9. The harmful substance in blood according to claim 6, wherein the harmful substance-bound albumin remover comprises a hollow fiber membrane having an albumin sieving coefficient of 0.05 or more and 0.8 or less. Removal method. 10. The method for removing harmful substances in blood according to claim 6, wherein the body fluid is blood.