Material for preventing leakage of digestive fluid and material for protecting organs from digestion by digestive fluid

Abstract

To provide a material or a method capable of replacing a conventional digestive fluid leakage preventing material and a conventional digestive fluid leakage preventing method.SOLUTION: The digestive fluid leakage prevention material of the present invention contains a self-assembling peptide gel, has an adhesion residual ratio of at least 40% with respect to a collagen sheet, and has a degradation rate of 35% or less when treated with pancreatic fluid at 37 °C for 7 days.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a material for preventing leakage of digestive fluids and a material for protecting organs from digestion by digestive fluids. [Background technology]

[0002] In surgery of the digestive organs, digestive fluids may leak from the digestive organs after surgery. For example, in the case of the pancreas, which produces pancreatic juice containing enzymes that break down proteins, fats, and sugars, pancreatic juice may leak from the pancreas after surgery. This is called pancreatic fistula, and it is considered a serious problem among postoperative complications because it can digest and dissolve the pancreas itself and surrounding tissues, causing inflammation.

[0003] Representative pancreatic surgeries include pancreaticoduodenectomy, performed for tumors near the head of the pancreas, and distal pancreatectomy, performed for tumors in the body or tail of the pancreas. In pancreaticoduodenectomy, the head of the pancreas, bile duct, duodenum, and part of the stomach are removed, and the pancreas, bile duct, and stomach are sutured to the small intestine, respectively. In distal pancreatectomy, the body and tail of the pancreas or tail are resected with a linear stapler and self-suturing, or the stump is closed by suturing. During this procedure, fibrin glue is sometimes applied to the anastomosis and / or stump to prevent pancreatic juice leakage due to incomplete anastomosis and / or incomplete closure of the stump. However, fibrin glue is digested by activated pancreatic juice and is therefore not a satisfactory method for preventing pancreatic juice leakage.

[0004] Furthermore, in any of the above surgical procedures, a drain is inserted near the anastomosis site or pancreatic stump, and the presence or absence of a pancreatic fistula is determined based on the amylase level in the drainage fluid and the duration of the level, etc. If the occurrence of a pancreatic fistula is confirmed, treatment is performed, such as administering medication or draining the pancreatic fluid externally using a drain. Furthermore, for example, Patent Document 1 proposes a method for closing a pancreatic fistula using a self-assembling peptide, but this method is intended to close the pancreatic fistula by using the self-assembling peptide to seal the hole left after removing the drain. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2019-508175 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made to solve the above-mentioned conventional problems, and its main object is to provide a digestive fluid leakage prevention material that can exert a good effect in terms of preventing pancreatic juice leakage. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided a material for preventing leakage of digestive fluids, which is composed of a self-assembling peptide gel containing a self-assembling peptide and water, has a residual adhesion rate to a collagen sheet of at least 40%, and has a decomposition rate of 35% or less when treated with pancreatic juice at 37°C for 7 days. In one embodiment, the self-assembling peptide comprises a self-assembling peptide that is positively charged at physiological pH. In one embodiment, the self-assembling peptide comprises a self-assembling peptide having a charge of +1 to +4 at physiological pH. In one embodiment, the viscosity measured using a rotational viscometer at a temperature of 25°C and a rotation speed of 0.5 rpm is 3.0 Pa·s or more. In one embodiment, the self-assembling peptide comprises a self-assembling peptide comprising the following amino acid sequence (A): Amino acid sequence (A): a1b1c1b2a2b3db4a3b5c2b6a4 (In the amino acid sequence, a1 to a4 are basic amino acid residues; b1 to b6 are uncharged polar amino acid residues and / or hydrophobic amino acid residues, provided that at least five of them are hydrophobic amino acid residues; c1 and c2 are acidic amino acid residues; and d is a hydrophobic amino acid residue or an uncharged polar amino acid residue.) In one embodiment, the self-assembling peptide comprises at least one selected from the self-assembling peptides shown in SEQ ID NOs: 1-13 and 16-18. In one embodiment, the material for preventing digestive fluid leakage is used to prevent leakage of pancreatic fluid from the pancreas. According to another aspect of the present invention, there is provided a method for preventing leakage of digestive fluids from the digestive tract, which comprises applying the digestive fluid leakage prevention material to a digestive organ that requires prevention of leakage of digestive fluids. According to yet another aspect of the present invention, there is provided an organ protection material against digestion by digestive fluids, which is composed of a self-assembling peptide gel containing a self-assembling peptide and water, has a residual adhesion rate to a collagen sheet of at least 40%, and has a decomposition rate of 35% or less when treated with pancreatic fluid at 37°C for 7 days. In one embodiment, the self-assembling peptide comprises a self-assembling peptide that is positively charged at physiological pH. In one embodiment, the self-assembling peptide comprises a self-assembling peptide having a charge of +1 to +4 at physiological pH. In one embodiment, the viscosity measured using a rotational viscometer at a temperature of 25°C and a rotation speed of 0.5 rpm is 3.0 Pa·s or more. In one embodiment, the self-assembling peptide comprises a self-assembling peptide comprising the following amino acid sequence (A): Amino acid sequence (A): a1b1c1b2a2b3db4a3b5c2b6a4 (In the amino acid sequence, a1 to a4 are basic amino acid residues; b1 to b6 are uncharged polar amino acid residues and / or hydrophobic amino acid residues, provided that at least five of them are hydrophobic amino acid residues; c1 and c2 are acidic amino acid residues; and d is a hydrophobic amino acid residue or an uncharged polar amino acid residue.) In one embodiment, the self-assembling peptide comprises at least one selected from the self-assembling peptides shown in SEQ ID NOs: 1-13 and 16-18. In one embodiment, the organ protector is used to protect an organ from digestion by pancreatic juice. According to yet another aspect of the present invention, there is provided a method for protecting an organ from digestion by digestive fluids, which comprises applying the organ protection material described above to the surface of the organ to be protected. [Effects of the Invention]

[0008] According to the present invention, by using a self-assembling peptide gel whose remaining adhesion rate to a collagen sheet is equal to or greater than a predetermined value and whose decomposition rate upon treatment with pancreatic juice is equal to or less than a predetermined value, a material can be provided that can exert a favorable effect in terms of preventing pancreatic juice leakage from the pancreas. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a graph showing the remaining adhesion rate of a self-assembling peptide gel. [Figure 2] 1 is a graph showing amylase levels in the ascites of rats. [Figure 3] 10 shows a microscopic photograph of the resected portion of the rat pancreas 3 days after surgery. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described, but the present invention is not limited to this embodiment.

[0011] A. Definitions (1) As used herein, the term "self-assembling peptide" refers to a peptide that can spontaneously assemble in an aqueous solution through interactions between peptide molecules to form nanometer-sized fibrous assemblies (hereinafter referred to as "nanofibers"). The interactions between peptide molecules are not particularly limited and include, for example, hydrogen bonds, ionic interactions, electrostatic interactions such as van der Waals forces, and non-covalent interactions such as hydrophobic interactions. The formation of nanofibers can be confirmed, for example, by electron microscopy.

[0012] (2) As used herein, the term "gel" refers to a viscoelastic substance that has both viscous and elastic properties. In one embodiment, a substance having a viscosity of 3 Pa s or greater as measured at 25°C and 0.5 rpm using a rotational viscometer can be called a gel.

[0013] (3) As used herein, the term “self-assembling peptide gel” refers to a gel formed by the spontaneous assembly of self-assembling peptides, which forms a three-dimensional network structure and retains water molecules within it.

[0014] (4) As used herein, "hydrophilic amino acids" include basic amino acids such as arginine (Arg / R), lysine (Lys / K), and histidine (His / H), acidic amino acids such as aspartic acid (Asp / D) and glutamic acid (Glu / E), and uncharged polar amino acids such as tyrosine (Tyr / Y), serine (Ser / S), threonine (Thr / T), asparagine (Asn / N), glutamine (Gln / Q), and cysteine ​​(Cys / C). The letters in parentheses above represent the three-letter and one-letter codes of the amino acids, respectively.

[0015] (5) As used herein, the term "hydrophobic amino acid" includes nonpolar amino acids such as alanine (Ala / A), leucine (Leu / L), isoleucine (Ile / I), valine (Val / V), methionine (Met / M), phenylalanine (Phe / F), tryptophan (Trp / W), glycine (Gly / G), and proline (Pro / P). The letters in parentheses above represent the three-letter and one-letter codes of the amino acids, respectively.

[0016] B. Digestive fluid leakage prevention material A digestive fluid leakage prevention material according to an embodiment of the present invention is composed of a self-assembling peptide gel containing a self-assembling peptide and water, has a residual adhesion rate to a collagen sheet of 40% or more, and a decomposition rate of 35% or less after treatment with pancreatic juice at 37°C for 7 days. This digestive fluid leakage prevention material is not significantly digested (decomposed) by digestive fluids and can be stably attached to cover sutured and / or closed sites in digestive organs, thereby effectively preventing leakage of digestive fluids from digestive organs. Furthermore, by promoting cell proliferation at the site of attachment, healing of the leakage site (sutured and / or closed site) can be promoted. Note that, in this specification, the term "prevention of digestive fluid leakage" encompasses the concept of preventing leakage of digestive fluids.

[0017] Examples of the digestive organs include the stomach, duodenum, small intestine, liver, gallbladder, pancreas, spleen, etc. In one embodiment, leakage of pancreatic juice from the pancreas and / or leakage of bile from the gallbladder (bile duct) can be prevented.

[0018] The residual adhesion rate of the digestive fluid leakage prevention material to the collagen sheet is typically 40% or more, preferably 45% or more, and more preferably 50% or more. The upper limit of the residual adhesion rate is not particularly limited, but can be, for example, 80%, or 70%. If the residual adhesion rate is within the above range, the material can remain stably attached to cover the sutured and / or closed parts of the digestive organs. The residual adhesion rate can be measured by the method described in the Examples. The residual adhesion rate can also be improved by, for example, using a self-assembling peptide that has a positive charge at physiological pH (pH = 7.4), increasing the peptide concentration, increasing the viscosity, etc.

[0019] The degradation rate of the digestive fluid leakage prevention material after treatment with pancreatic juice (exposure to pancreatic juice) at 37°C for 7 days is typically 35% or less, preferably 30% or less, more preferably 15% or less, and even more preferably 0% to 10%. If the degradation rate after pancreatic juice treatment is within the above range, the material will not be significantly degraded by the digestive juice whose leakage is to be prevented, and will remain stably attached to the surface of the digestive organs. Here, the degradation rate after pancreatic juice treatment can be measured using simulated pancreatic juice (e.g., a 1 mg / mL aqueous solution of a digestive enzyme preparation containing 1 g of Japanese Pharmacopoeia pancreatin per 1 g), as described in the Examples. Peptides are generally degraded by pancreatic juice containing peptidases, but self-assembled peptide assemblies (specifically, self-assembling peptide gels) are less susceptible to degradation by pancreatic juice, and therefore can function favorably as a digestive fluid leakage prevention material.

[0020] The viscosity of the digestive fluid leakage prevention material may be, for example, 3.0 Pa s or more, preferably 9.0 Pa s or more, more preferably 15.0 Pa s or more, even more preferably 25.0 Pa s or more, and even more preferably 35.0 Pa s or more. The viscosity of the digestive fluid leakage prevention material may be, for example, 1000 Pa s or less, or, for example, 100 Pa s or less. The concentration is the viscosity measured using a rotational viscometer at a temperature of 25°C and a rotation speed of 0.5 rpm.

[0021] The pH of the material for preventing leakage of digestive fluids is preferably a pH at which the self-assembling peptides that make up the self-assembling peptide gel can maintain their charge at physiological pH, and can be, for example, 5.0 to 9.0, preferably 5.5 to 8.0, and more preferably 5.5 to 7.5.

[0022] As described above, the material for preventing leakage of digestive fluids is composed of a self-assembling peptide gel containing a self-assembling peptide and water. The self-assembling peptide gel can further contain pharmaceutically acceptable additive components depending on the purpose.

[0023] B-1. Self-assembling peptides The self-assembling peptide preferably has a positive charge at physiological pH (pH = 7.4). Specifically, a self-assembling peptide having a charge of, for example, +1 to +4, preferably +1 to +3, more preferably +2 or +3, and even more preferably +2 per molecule at physiological pH can be used. Such self-assembling peptides are suitable for forming nanofibers and gels. Furthermore, self-assembling peptide gels formed by such self-assembling peptides exhibit reversible self-assembly, whereby fluidity increases upon physical stimulation, such as stirring, vibration, or application of shear force, and decreases upon cessation of the physical stimulation. This has the advantage of reducing the load imposed when administered using a long, thin instrument such as a syringe or catheter. Furthermore, self-assembling peptide gels formed using positively charged self-assembling peptides exhibit excellent retention on the surfaces of organs such as the digestive tract and mucous membranes. Although not limiting the present invention, it is speculated that the reason for this effect is that the self-assembling peptide gel formed using the positively charged self-assembling peptide is positively charged overall, and electrostatic interaction occurs between the gel and the negatively charged cell surface, resulting in improved adhesion between the two.

[0024] On the other hand, self-assembling peptide gels formed from self-assembling peptides that are uncharged or negatively charged at physiological pH (resulting in a self-assembling peptide gel that is uncharged or negatively charged overall) may not retain sufficient retention on the surfaces of organs such as the digestive tract or mucous membranes because no electrostatic attraction is generated between the gel and negatively charged cell surfaces.

[0025] Furthermore, self-assembling peptides that are uncharged at physiological pH typically have irreversible self-assembly ability, and upon a change in the pH of the peptide solution or in response to inorganic salts, they initiate nanofiber formation and gel. Therefore, since gelation progresses after administration of such self-assembling peptides in solution to the sutured and / or closed site of the digestive organ, they tend to spread along the surface of the administration site until gelation occurs, which can make it difficult to quickly form a gel of sufficient thickness.

[0026] The charge of the self-assembling peptide refers to the sum of the charges of the amino acid residues contained in the peptide molecule. The charge at physiological pH can be calculated using, for example, the PROTEIN CALCULATOR v3.4 program available on the website (http: / / protcalc.sourceforge.net / ).

[0027] The number of amino acid residues constituting the self-assembling peptide is, for example, 9 or more, preferably 10 to 40, more preferably 10 to 32, and even more preferably 12 to 32. The N-terminal amino group and / or C-terminal carboxyl group of the peptide may be appropriately protected with a protecting group such as an acetyl group or an amide group.

[0028] Examples of the self-assembling peptides that can be used include peptides in which acidic and basic amino acid residues are alternately arranged at odd-numbered (or even-numbered) positions, with any one to four, preferably two to three, of the acidic amino acid residues being substituted with uncharged polar amino acid residues or hydrophobic amino acid residues, and all of the amino acid residues at even-numbered (or odd-numbered) positions being hydrophobic amino acid residues. In aqueous solution, such peptides form β-sheets consisting of a hydrophobic face containing only hydrophobic amino acid residues and a hydrophilic face containing hydrophilic amino acid residues. The two β-sheets extend with the hydrophobic faces facing inward, resulting in the formation of nanofibers. The nanofibers further aggregate due to the interaction between the hydrophilic faces, forming a network structure that can gel. The formation of a β-sheet structure can be confirmed, for example, by measuring the molar ellipticity using circular dichroism spectroscopy and confirming that the molar ellipticity at 216 nm is negative. Furthermore, FT-IR analysis can be used to confirm that the molar ellipticity at 1620 cm -1 The peak due to the β-sheet appears near 1690 cm -1 This can also be confirmed by detecting a peak due to antiparallel β-sheets that appears nearby.

[0029] An example of the self-assembling peptide is a peptide comprising the following amino acid sequence (A): The self-assembling peptide may be a peptide consisting of the following amino acid sequence (A), or may be a peptide to which several, for example, one to five, arbitrary amino acid residues have been added to the N-terminus and / or C-terminus, as long as the effects of the present invention are achieved. Furthermore, the N-terminal amino group of the peptide may be acetylated, and the C-terminal carboxyl group may be amidated, as necessary. Amino acid sequence (A): a1b1c1b2a2b3db4a3b5c2b6a4 (In the amino acid sequence, a1 to a4 are basic amino acid residues; b1 to b6 are uncharged polar amino acid residues and / or hydrophobic amino acid residues, provided that at least five of them are hydrophobic amino acid residues; c1 and c2 are acidic amino acid residues; and d is a hydrophobic amino acid residue or an uncharged polar amino acid residue.)

[0030] In one embodiment, in the amino acid sequence, b1 to b6 are all hydrophobic amino acid residues. b1 to b6 may each independently be an alanine residue, a valine residue, a leucine residue, or an isoleucine residue, and are preferably an alanine residue or a leucine residue. More preferably, b1 to b6 are all leucine residues, or five of them are leucine residues and one is an alanine residue.

[0031] In one embodiment, in the above amino acid sequence, d is an alanine residue, leucine residue, asparagine residue, serine residue, or glutamine residue.

[0032] In one embodiment, in the above amino acid sequence, all of a1 to a4 are arginine or lysine, and preferably arginine.

[0033] In one embodiment, in the above amino acid sequence, c1 and c2 are both aspartic acid or glutamic acid, and preferably aspartic acid.

[0034] The self-assembling peptides that can be used in the present invention are not limited to peptides containing the above amino acid sequence (A). For example, the peptides described in WO2007 / 000979 can be used.

[0035] Specific examples of the self-assembling peptides include the peptides of SEQ ID NOs: 1 to 13 and 16 to 18. Of these, the peptides of SEQ ID NOs: 1 to 4 are more preferred. As long as the effects of the present invention are achieved, one type of self-assembling peptide may be used alone, or two or more types may be used in combination.

[0036] [Table 1]

[0037] The blending ratio of the self-assembling peptide in the digestive fluid leakage prevention material (self-assembling peptide gel) can be appropriately set depending on the desired residual adhesion rate, decomposition rate after pancreatic juice treatment, etc. The blending ratio can be, for example, 0.3 w / w% to 6.0 w / w%, preferably 0.5 w / w% to 5.0 w / w%, more preferably 0.6 w / w% to 4.0 w / w%, even more preferably 0.8 w / w% to 3.0 w / w%, and even more preferably 1.0 w / w% to 2.0 w / w%.

[0038] The self-assembling peptide can be prepared by any appropriate method, such as liquid phase synthesis, solid phase synthesis, molecular biological techniques, etc. The self-assembling peptide may be in the form of a salt due to the production method, and a material for preventing leakage of digestive fluids using a self-assembling peptide in the form of a salt is also included in embodiments of the present invention.

[0039] B-2.Water Examples of water include distilled water, deionized water, pure water, etc. Water, together with the added components described below, can constitute an aqueous medium such as physiological saline, buffered saline (PBS, etc.), phosphate buffer, isotonic aqueous buffer, etc.

[0040] The blending ratio of water in the digestive fluid leakage prevention material (self-assembling peptide gel) is, for example, 80% by weight or more, preferably 85% by weight or more, and more preferably 90% by weight or more.

[0041] B-3.Additional ingredients As the pharmaceutically acceptable additive, any appropriate additive can be selected by a person skilled in the art depending on the purpose, etc. Specific examples include pH adjusters, isotonicity agents, drugs, preservatives, excipients, stabilizers, fillers, solubilizers, etc. One type of additive may be used alone, or two or more types may be used in combination.

[0042] Examples of pH adjusters include citric acid, trisodium citrate, succinic acid, monosodium succinate, disodium succinate, sodium acetate, sodium bicarbonate, sodium carbonate, phosphoric acid, disodium hydrogen phosphate, sodium dihydrogen phosphate, histidine, and lysine.

[0043] Examples of isotonic agents include sodium chloride, polyethylene glycol, dextran, mannitol, sorbitol, inositol, glucose, fructose, lactose, xylose, mannose, maltose, sucrose, trehalose, and raffinose.

[0044] Any appropriate drug can be used as long as the effects of the present invention are obtained. Specific examples of drugs include anti-inflammatory drugs, protease inhibitors (e.g., gabexate mesilate), steroids, antibiotics, etc.

[0045] B-4. Manufacturing method for preventing leakage of digestive fluids The digestive fluid leakage prevention material can be produced by any appropriate production method. For example, the digestive fluid leakage prevention material can be obtained by mixing a self-assembling peptide, water, and any additives. If necessary, each component or the mixture may be sterilized before mixing. Any appropriate method applicable in the art may be used for the mixing method and the sterilization method. The self-assembling peptide gel that constitutes the digestive fluid leakage prevention material is stable even at high temperatures, so it can also be subjected to high-pressure steam sterilization.

[0046] C. Methods for preventing leakage of digestive fluids According to another aspect of the present invention, there is provided a method for preventing leakage of digestive fluids, which comprises applying the material for preventing leakage of digestive fluids described in Section B to a digestive tract that requires prevention of leakage of digestive fluids.

[0047] An example of an application method is to apply the digestive fluid leakage prevention material to the surface of the digestive organ so as to cover or seal areas where digestive fluids may leak (such as areas of suture failure, perforations, cut surfaces, etc.). In one embodiment, the digestive fluid leakage prevention material is dispensed to the desired area using a tubular instrument such as a syringe, needle, pipette, catheter, or tube, and then spread using a spatula, cotton swab, or the like, as needed. Alternatively, the material may be applied by spraying, for example, using a sprayer. As described above, the fluidity of the digestive fluid leakage prevention material increases when physical stimuli such as shear force are applied, and it can return to its original fluidity when the physical stimuli are stopped. Therefore, when the above-mentioned tubular instrument is used, the fluidity of the digestive fluid leakage prevention material is increased, allowing it to be easily dispensed with a small pressure, while the material quickly returns to its original fluidity after dispensing, allowing the material to be stably attached to the surface of the digestive organ.

[0048] The amount of coating may be any appropriate amount as long as the effects of the present invention are obtained, for example, an amount that results in a coating thickness of 0.01 mm or more and less than 3 cm, preferably 0.05 mm or more and less than 1 cm.

[0049] Examples of digestive organs that require prevention of leakage of digestive fluids include the stomach, duodenum, small intestine, liver, gallbladder, pancreas, spleen, etc. In particular, the material for preventing leakage of digestive fluids and the method for preventing leakage of digestive fluids are preferably applied to the duodenum, gallbladder, and pancreas, and are effective in preventing pancreatic fistula and / or bile fistula. The digestive organs are preferably those of humans or non-human animals (e.g., non-human primates, dogs, cats, rats, cows, pigs, sheep, etc.).

[0050] D. Organ protection material Another aspect of the present invention provides an organ protection material. The organ protection material of this embodiment is composed of a self-assembling peptide gel containing a self-assembling peptide and water, and has a residual adhesion rate of 40% or more to a collagen sheet and a decomposition rate of 35% or less after treatment with pancreatic juice at 37°C for 7 days. This organ protection material can prevent the surrounding organs from being extensively digested (decomposed) by the digestive juice, even in the event of leakage of the digestive juice.

[0051] The organs to be protected are those present in the abdominal cavity, including, for example, internal organs such as the stomach, duodenum, small intestine, large intestine, liver, gallbladder, pancreas, spleen, and kidneys, and circulatory organs such as blood vessels.

[0052] The residual adhesion rate of the organ protection material to the collagen sheet is typically 40% or more, preferably 45% or more, and more preferably 50% or more. The upper limit of the residual adhesion rate is not particularly limited, but can be, for example, 80% or 70%. If the residual adhesion rate is within the above range, the material can remain stably attached to the surface of the organ to be protected. The residual adhesion rate can be measured by the method described in the Examples. The residual adhesion rate can also be improved by, for example, using a peptide that has a positive charge at physiological pH (pH = 7.4), increasing the peptide concentration, or increasing the viscosity.

[0053] The decomposition rate of the organ protection material after treatment with pancreatic juice at 37°C for 7 days is typically 35% or less, preferably 30% or less, more preferably 15% or less, and even more preferably 0% to 10%. If the decomposition rate after treatment with pancreatic juice is within the above range, the organ to be protected will not be significantly decomposed by digestive juice, and contact with the digestive juice can be prevented. Here, the decomposition rate after treatment with pancreatic juice can be measured using simulated pancreatic juice (e.g., a 1 mg / mL aqueous solution of a digestive enzyme preparation containing 1 g of Japanese Pharmacopoeia pancreatin per 1 g), as described in the Examples. Peptides are generally decomposed by pancreatic juice containing peptidases, but self-assembled peptide assemblies (specifically, self-assembling peptide gels) are less susceptible to decomposition by pancreatic juice and can therefore function favorably as organ protection materials.

[0054] The viscosity of the organ protection material may be, for example, 3.0 Pa·s or more, preferably 9.0 Pa·s or more, more preferably 15.0 Pa·s or more, even more preferably 25.0 Pa·s or more, and even more preferably 35.0 Pa·s or more. The viscosity of the organ protection material may be, for example, 1000 Pa·s or less, or, for example, 100 Pa·s or less. The concentration is measured using a rotational viscometer at a temperature of 25°C and a rotation speed of 0.5 rpm.

[0055] The pH of the organ protective material is preferably such that the self-assembling peptides that make up the self-assembling peptide gel can maintain their charge at physiological pH, and the pH of the organ protective material can be, for example, 5.0 to 9.0, preferably 5.5 to 8.0, and more preferably 5.5 to 7.5.

[0056] As described above, the organ protection material is composed of a self-assembling peptide gel containing a self-assembling peptide and water. The self-assembling peptide gel may further contain pharmaceutically acceptable additives depending on the purpose. The self-assembling peptide gel may be the same as the self-assembling peptide gel constituting the agent for preventing leakage of digestive fluids described in Section B.

[0057] E. Organ Protection Methods According to another aspect of the present invention, there is provided a method for protecting an organ from digestion by digestive fluids, which comprises applying the organ protector described in Section D to the surface of the organ to be protected.

[0058] An example of an application method is to apply the organ protection material to the surface of the organ to be protected so as to cover at least a portion of the surface. In one embodiment, the organ protection material is dispensed to the desired location using a tubular instrument such as a syringe, needle, pipette, catheter, or tube, and then spread using a spatula, cotton swab, or the like, as needed. Application by spraying, for example, using a sprayer, may also be performed. As described above, the fluidity of the organ protection material increases when subjected to physical stimulation such as shear force, and can return to its original fluidity when the physical stimulation is stopped. Therefore, when the tubular instrument is used, the fluidity of the organ protection material is increased, allowing it to be easily dispensed with a small pressure, while the material quickly returns to its original fluidity after dispensing, allowing the organ protection material to be stably attached to the organ surface.

[0059] The amount of coating may be any appropriate amount as long as the effects of the present invention are obtained, for example, an amount that results in a coating thickness of 0.01 mm or more and less than 3 cm, preferably 0.05 mm or more and less than 1 cm.

[0060] Organs that require protection from digestion by digestive fluids include, for example, internal organs such as the stomach, duodenum, small intestine, large intestine, liver, gallbladder, pancreas, spleen, and kidneys, and circulatory organs such as blood vessels. The above organs are preferably those of humans or non-human animals (e.g., non-human primates, dogs, cats, rats, cows, pigs, sheep, etc.). [Example]

[0061] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0062] ≪Viscosity≫ The viscosity (Pa·s) of the sample was measured using a rotational viscometer (manufactured by Toki Sangyo Co., Ltd., product name "TVE-20LT") which is a viscosity measuring device. Specifically, it is as follows. First, approximately 0.2 g of the sample was weighed into a sample cup, attached to the viscometer main body, and water adjusted to 25 ± 0.2 °C was circulated for 15 minutes or more. Then, the cone rotor (manufactured by Toki Sangyo Co., Ltd., 3°×R9.7) was rotated at 0.5 rpm in the measurement range M, and the average of the viscosities displayed on the screen approximately 15, 20, and 25 minutes after the start of rotation was taken as the viscosity. ≪Degradation rate by pancreatic juice treatment≫ On 0.1 g of the sample (gel) placed in a 1.5 mL tube, 200 μL of simulated pancreatic juice (manufactured by Maruishi Pharmaceutical Co., Ltd., product name: Pancreatin powder "Maruishi" (a digestive enzyme preparation containing 1 g of Nippon Pharmaceutical Pancreatin per 1 g) aqueous solution of 1 mg / mL) or PBS was allowed to stand at 37 °C for 7 days. To the tube after standing, 1 mL of trifluoroacetic acid (manufactured by Wako Pure Chemical Industries, Ltd., for peptide synthesis) was added and mixed well. To the mixture, 14 mL of trifluoroacetic acid was further added and made up to 25 mL with distilled water, and this was used as a sample for HPLC measurement. The sample for HPLC measurement was subjected to HPLC measurement under the following conditions, and the degradation rate after pancreatic juice treatment was determined based on the following formula. In addition, the distilled water used in the preparation was subjected to HPLC measurement under the same conditions as the sample solution, and baseline correction was performed by subtracting from each chromatogram. Degradation rate by pancreatic juice treatment (%) = (Peak area of self-assembled peptide in PBS-immersed sample - Peak area of self-assembled peptide in simulated pancreatic juice-immersed sample) ÷ Peak area of self-assembled peptide in PBS-immersed sample × 100 <HPLC measurement conditions> · Device 1 (used for analysis of self-assembled peptide gels 1 to 4): M515 Pump, In-Line Degasser AF, 717 Autosampler, 996 Photodiode Array Detector, 2410 Refractive Index Detector, column heater manufactured by Waters Apparatus 2 (used for the analysis of self-assembling peptide gels 5–7): Waters e2695 Separations Module, Waters 2998 Photodiode Array Detector, Waters SMH Column Heater, Empower 3 Feature Release 3 Hotfix 1, Column Heater: JASCO 860-CO Column: YMC-Triart C18 3mm x 250mm, φ3μm Column heater temperature setting: 67℃ Detection wavelength: 205nm Analysis time: 60 minutes (Self-assembling peptide gels 3 and 5-7) or 110 minutes (Self-assembling peptide gels 1, 2, and 4) Mobile phase: Solution A: 600 mL of distilled water, 200 mL of acetonitrile, 0.8 mL of trifluoroacetic acid Solution B: 250 mL of distilled water, 250 mL of acetonitrile, 0.5 mL of trifluoroacetic acid [Table 2] [Table 3] ·Flow rate: 0.4mL / min ·Injection volume: 60μL ≪Adhesion remaining rate≫ A collagen sheet (Nippi Collagen Industrial Co., Ltd., product number 40322223) was hollowed out with an 8 mm trephine and immersed in saline for at least 30 minutes. After removal from the saline and lightly draining, 10 μL of the sample (self-assembling peptide gel) was applied to the collagen sheet, and the weight (A) of the collagen sheet after application was measured. The opposite side of the collagen sheet to the sample-applied side was then lightly wetted with saline containing 0.1% Pancreatin Maruishi and attached to a 6-well plate (Corning Cell Culture 6-Well Multiwell Plate) with the sample-applied side facing up. This plate was centrifuged at 800 rpm for 20 seconds in a plate centrifuge (Kubota Shoji Co., Ltd., product name PlateSpin). After centrifugation, the collagen sheet was peeled off the plate, its weight (B) was measured, and the remaining adhesion rate was calculated using the following formula: For each sample, the above measurement and calculation of the residual adhesion rate were carried out for N=8, and the average value was taken as the residual adhesion rate for each sample. Adhesion remaining rate (%) = (B) / (A) x 100

[0063] [Preparation Example 1: Self-assembling peptide gel 1] A steam-sterilized self-assembling peptide gel (pH 5.9) containing 1.5 w / w% self-assembling peptide (SEQ ID NO: 1: Ac-RLDLRLALRLDLR-CONH2), an isotonicity agent, a pH adjuster, and water was used as self-assembling peptide gel 1. After treatment with pancreatic juice, the decomposition rate of self-assembling peptide gel 1 was 8.8%, and the viscosity was 35 Pa·s or higher (above the measurement range). Furthermore, the residual adhesion rate was 54.4%, as shown in Figure 1.

[0064] [Preparation Example 2: Self-assembling peptide gel 2] Self-assembling peptide gel 2 (pH 5.8) was obtained by mixing 1.5 w / w% of the self-assembling peptide (SEQ ID NO: 14: Ac-SAEASAEASAEAKAEA-CONH2), an isotonicity agent, a pH adjuster, and water. The decomposition rate of self-assembling peptide gel 2 after treatment with pancreatic juice was less than 10%. Furthermore, the residual adhesion rate was 33.4%, as shown in Figure 1.

[0065] [Preparation Example 3: Self-assembling peptide gel 3] A self-assembling peptide gel (pH 2.2) containing 1.5 w / w% self-assembling peptide (SEQ ID NO: 15: Ac-RADARADARADARADA-CONH2) and water was used as self-assembling peptide gel 3. After treatment with pancreatic juice, the decomposition rate of self-assembling peptide gel 3 was less than 10%, and the viscosity was 11.0 Pa s. Furthermore, the residual adhesion rate was 36.5%, as shown in Figure 1.

[0066] [Preparation Example 4: Self-assembling peptide gel 4] Self-assembling peptide gel 4 (pH 6.0) was obtained by mixing 0.8 w / w% self-assembling peptide (SEQ ID NO: 1: Ac-RLDLRLALRLDLR-CONH2), an isotonicity agent, a pH adjuster, and water. After treatment with pancreatic juice, the degradation rate of self-assembling peptide gel 4 was 28%, and the viscosity was 11.2 Pa s. Furthermore, the residual adhesion rate was 45.9%, as shown in Figure 1.

[0067] [Preparation Example 5: Self-assembling peptide gel 5] Self-assembling peptide gel 5 (pH 6.8) was obtained by mixing 1.5 w / w% of the self-assembling peptide (SEQ ID NO: 16: Ac-RASARASARASARASA-CONH2), an isotonicity agent, a pH adjuster, and water. The degradation rate of self-assembling peptide gel 5 after treatment with pancreatic juice was 30.4%. Furthermore, the residual adhesion rate was 57.7%, as shown in Figure 1.

[0068] [Preparation Example 6: Self-assembling peptide gel 6] Self-assembling peptide gel 6 (pH 6.2) was obtained by mixing 1.5 w / w% of the self-assembling peptide (SEQ ID NO: 17: Ac-RASARASARASARADA-CONH2), an isotonicity agent, a pH adjuster, and water. The degradation rate of self-assembling peptide gel 6 after treatment with pancreatic juice was 5.7%. Furthermore, the residual adhesion rate was 70.6%, as shown in Figure 1.

[0069] [Preparation Example 7: Self-assembling peptide gel 7] Self-assembling peptide gel 7 (pH 7.7) was obtained by mixing 1.5 w / w% of the self-assembling peptide (SEQ ID NO: 18: Ac-RASARADARADARADA-CONH2), an isotonicity agent, a pH adjuster, and water. The degradation rate of self-assembling peptide gel 7 after treatment with pancreatic juice was 2.1%. Furthermore, the residual adhesion rate was 59.0%, as shown in Figure 1.

[0070] [Test Example 1] SD rats (8 weeks old) underwent abdominal surgery under deep anesthesia, and a portion of the pancreas was resected. Self-assembling peptide gel 1 or self-assembling peptide gel 3 was applied to a thickness of 0.1 mm or more to cover the resected surface, and the abdomen was then closed. A control rat was also closed without applying any gel to the resected surface. Three days after surgery, the abdomen was opened again, ascites fluid was collected, and the rats were euthanized (N=9). The amylase level (Amy) in the ascites was then measured. The results are shown in Figure 2 (mean ± SD). Microscopic photographs of the resected pancreatic area three days after surgery are shown in Figure 3.

[0071] As can be seen from Figure 2, self-assembling peptide gel 1, which has a residual adhesion rate to the collagen sheet equal to or greater than a predetermined value and a decomposition rate due to pancreatic juice treatment equal to or less than a predetermined value, is more effective at preventing pancreatic juice leakage than self-assembling peptide gel 3.

[0072] Furthermore, as shown in Figure 3, the amount of self-assembling peptide gel remaining on the pancreatic surface coated with self-assembling peptide gel 3 was significantly less than that on the pancreatic surface coated with self-assembling peptide gel 1. This indicates that the difference in the effectiveness of preventing digestive fluid leakage is due to the difference in the rate at which the self-assembling peptide gel remains attached to the digestive organs. Furthermore, considering Figure 1, it is suggested that the charge of the self-assembling peptide causes a difference in the adhesive strength with the organ surface. [Industrial Applicability]

[0073] The material for preventing leakage of digestive fluids and the material for protecting organs of the present invention can be suitably used in the medical field.

Claims

1. The self-assembling peptide gel comprises a self-assembling peptide and water, The remaining adhesion rate to the collagen sheet is at least 40%; The decomposition rate after treatment with pancreatic juice at 37°C for 7 days is 35% or less, A material for preventing leakage of digestive fluids, wherein the self-assembling peptide gel is positively charged overall at physiological pH.

2. The material for preventing leakage of digestive fluids according to claim 1 , wherein the self-assembling peptide comprises a self-assembling peptide that has a positive charge at physiological pH.

3. 3. The material for preventing leakage of digestive fluids according to claim 2, wherein the self-assembling peptide comprises a self-assembling peptide having a charge of +1 to +4 at physiological pH.

4. 4. The material for preventing leakage of digestive fluids according to claim 1, which has a viscosity of 3.0 Pa·s or more when measured using a rotational viscometer at a temperature of 25° C. and a rotation speed of 0.5 rpm.

5. The material for preventing leakage of digestive fluids according to claim 1 , wherein the self-assembling peptide comprises a self-assembling peptide comprising the following amino acid sequence (A): Amino acid sequence (A): a １ b １ c １ b ２ a ２ b ３ db ４ a ３ b ５ c ２ b ６ a ４ (In the amino acid sequence, a １ ~a ４ is a basic amino acid residue; b １ ~b ６ are uncharged polar amino acid residues and / or hydrophobic amino acid residues, provided that at least five of them are hydrophobic amino acid residues; １ and c ２ is an acidic amino acid residue; and d is a hydrophobic amino acid residue or an uncharged polar amino acid residue.

6. The material for preventing leakage of digestive fluids according to any one of claims 1 to 4, wherein the self-assembling peptide comprises at least one selected from the self-assembling peptides shown in SEQ ID NOs: 1 to 13 and 16 to 18.

7. The material for preventing leakage of digestive fluids according to any one of claims 1 to 6, for preventing leakage of pancreatic juice from the pancreas.

8. The self-assembling peptide gel comprises a self-assembling peptide and water, The remaining adhesion rate to the collagen sheet is at least 40%; The decomposition rate after treatment with pancreatic juice at 37°C for 7 days is 35% or less, A material for protecting organs from digestion by digestive fluids, wherein the self-assembling peptide gel is positively charged overall at physiological pH.

9. The organ protector of claim 8 , wherein the self-assembling peptide comprises a self-assembling peptide that is positively charged at physiological pH.

10. The organ protective material according to claim 9, wherein the self-assembling peptide comprises a self-assembling peptide having a charge of +1 to +4 at physiological pH.

11. 11. The organ protecting material according to claim 8, which has a viscosity of 3.0 Pa·s or more when measured using a rotational viscometer at a temperature of 25°C and a rotation speed of 0.5 rpm.

12. The organ protective material according to any one of claims 8 to 11, wherein the self-assembling peptide comprises a self-assembling peptide comprising the following amino acid sequence (A): Amino acid sequence (A): a １ b １ c １ b ２ a ２ b ３ db ４ a ３ b ５ c ２ b ６ a ４ (In the amino acid sequence, a １ ~a ４ is a basic amino acid residue; b １ ~b ６ are uncharged polar amino acid residues and / or hydrophobic amino acid residues, provided that at least five of them are hydrophobic amino acid residues; １ and c ２ is an acidic amino acid residue; and d is a hydrophobic amino acid residue or an uncharged polar amino acid residue.

13. The organ protective material according to any one of claims 8 to 11, wherein the self-assembling peptide comprises at least one selected from the self-assembling peptides shown in SEQ ID NOs: 1 to 13 and 16 to 18.

14. The organ protecting material according to any one of claims 8 to 13, for protecting an organ from digestion by pancreatic juice.

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