Treatment of neuropathic pain

Abstract

This provides treatment methods for neuropathic pain. [Solution] A method for treating neuropathic pain is provided, comprising administering a lipoxin A4, 5,6-EET, 17-HDHA, 10,11-EpDPA, 8,9-EpETE, 14,15-EpETE, or 15-HETrE production inhibitor to a subject. Alternatively, a composition for use in the treatment of neuropathic pain is provided, comprising a lipoxin A4, 5,6-EET, 17-HDHA, 10,11-EpDPA, 8,9-EpETE, 14,15-EpETE, or 15-HETrE production inhibitor.

Description

[Technical Field]

[0001] The technical field of the present invention relates to the treatment of neuropathic pain. [Background Art]

[0002] Pain is broadly classified into two categories: inflammatory pain caused by inflammation, and neuropathic pain caused by nerve damage or dysfunction. A typical example of a disease accompanied by pain is osteoarthritis. Osteoarthritis is a disease in which symptoms such as chronic pain, gait disturbance and hyperalgesia greatly reduce the patient's quality of life, and it is considered to have not only inflammatory pain but also neuropathic pain aspects. In fact, the effect of classical analgesics such as NSAIDs that inhibit the production of prostaglandins, which are inflammatory mediators involved in inflammatory pain, on osteoarthritis is limited (Non-Patent Document 1), and the development of treatment methods targeting the neuropathic pain aspect is desired. [Prior Art Documents] [Non-Patent Documents]

[0003] [Non-Patent Document 1] Vo et.al., Pain, 2009 ;143(3):169-171. [Summary of the Invention] [Problems to be Solved by the Invention]

[0004] Many aspects of the pathology of neuropathic pain remain unclear, and available treatment methods are also limited.

[0005] On the other hand, the inventors of the present application have clarified that inhibition of lipid metabolite production provides an excellent therapeutic effect on neuropathic pain. [Means for Solving the Problems]

[0006] According to one aspect of the present invention, a method for treating neuropathic pain is provided, comprising administering to a subject an inhibitor of Lipoxin A4, 5,6-EET, 17-HDHA, 10,11-EpDPA, 8,9-EpETE, 14,15-EpETE, or 15-HETrE production. This method provides excellent therapeutic effects for neuropathic pain.

[0007] According to one aspect of the present invention, a composition for use in the treatment of neuropathic pain is provided, comprising an inhibitor of the production of Lipoxin A4, 5,6-EET, 17-HDHA, 10,11-EpDPA, 8,9-EpETE, 14,15-EpETE, or 15-HETrE. Using this composition, excellent therapeutic effects against neuropathic pain can be obtained. [Brief explanation of the drawing]

[0008] [Figure 1] The results of the von Frey test in healthy rats and rat models of arthritis are shown. [Figure 2] The results of the incapacitance test in healthy rats and rat models of arthritis are shown. [Figure 3] This chart shows the concentration levels of representative arachidonic acid cyclooxygenase metabolites in the subpatellar adipose tissue of healthy and arthritis-affected rat models. Left (white): healthy group, Right (black): arthritis group [Figure 4] This chart shows representative lipoxygenase metabolite levels of arachidonic acid in subpatellar adipose tissue of healthy and arthritis-affected rat models. Left (white): healthy group, Right (black): arthritis group [Figure 5] This graph shows representative levels of arachidonic acid cyclooxygenase metabolites and dihomo-γ-linolenic acid lipoxygenase metabolites in the dorsal root ganglia of healthy rats and rats with arthritis. Left (white): Healthy group, Right (black): Arthritis group [Figure 6] The results of immunohistochemical staining with 15-lipoxygenase antibody in the dorsal root ganglia of a rat model of arthritis are shown. [Figure 7]The results of TRPV1 channel Ca2+ imaging of cyclooxygenase metabolites are shown. [Figure 8] The results of TRPV1 channel Ca2+ imaging of lipoxygenase metabolites and cytochrome p450 metabolites are shown. [Figure 9] The results of TRPV1 channel Ca2+ imaging for representative cyclooxygenase and lipoxygenase metabolites are shown. [Figure 10] The results of the von Frey test after administration of Vehicle, NDGA, or tramadol in a rat model of arthropathy are shown. [Figure 11] The results of incapacitance tests in rat models of arthritis after administration of vehicle, NDGA, or tramadol are shown. [Figure 12] This chart shows representative arachidonic acid cyclooxygenase metabolite levels in subpatellar adipose tissue after administration of Vehicle, NDGA, or tramadol in rat models of arthritis. Left: Vehicle group, Middle: NDGA group, Right: Tramadol group [Figure 13] This chart shows representative levels of dihomo-γ-linolenic acid lipoxygenase metabolites in subpatellar adipose tissue after administration of vehicle, lipoxygenase inhibitor, or tramadol in a rat model of arthritis. Left: Vehicle group, Middle: NDGA group, Right: Tramadol group [Modes for carrying out the invention]

[0009] The embodiments of the present invention will be described in detail below. To avoid repetition and unnecessary complexity, similar information will be omitted from the explanation as appropriate.

[0010] (1) Method According to one embodiment of the present invention, there is provided a method for treating neuropathic pain, the method comprising administering to a subject an inhibitor of production of Lipoxin A4, 5,6-EET, 17-HDHA, 10,11-EpDPA, 8,9-EpETE, 14,15-EpETE, or 15-HETrE. Use of this method can provide an excellent therapeutic effect against neuropathic pain. The excellent therapeutic effect may include, for example, an effect of reducing pain intensity in a subject, or an effect of improving physical function in a subject. In animal models, pain intensity can be evaluated using, for example, von Frey test, Incapacitance test for evaluating the balance of animal posture and the balance of weight load applied to each limb, and evaluation of gait and exercise amount; in humans, pain intensity can be evaluated using, for example, a numerical rating scale (NRS) or a visual analog scale (VAS).

[0011] (2) Method The method according to one embodiment of the present invention (e.g., the above (1)) may include, for example, (i) a step of examining whether a subject suffers from neuropathic pain, (ii) a step of identifying a subject having neuropathic pain, (iii) a step of identifying a subject in need of treatment for neuropathic pain, or (iv) a step of identifying a subject in need of prevention of neuropathic pain. In addition, the method according to one embodiment of the present invention (e.g., the above (1)) may include, for example, a step of examining lipid metabolites in a biological sample of a subject, or a step of identifying a subject in whom a certain level of lipid metabolites is confirmed in a biological sample as a subject to be treated.

[0012] (3) Composition According to one embodiment of the present invention, there is provided a composition for use in the treatment of neuropathic pain, wherein the composition comprises an inhibitor of production of Lipoxin A4, 5,6-EET, 17-HDHA, 10,11-EpDPA, 8,9-EpETE, 14,15-EpETE, or 15-HETrE. Excellent therapeutic effects on neuropathic pain can be obtained by using this composition. The excellent therapeutic effect may include, for example, an effect of reducing pain intensity in a subject, or an effect of improving physical function of a subject. In animal models, pain intensity can be evaluated using, for example, the von Frey test, the Incapacitance test that evaluates the postural balance of animals and the balance of weight load applied to each limb, and evaluation of gait and exercise amount; in humans, it can be evaluated using, for example, a numerical rating scale (NRS) or a visual analog scale (VAS). The composition may be a pharmaceutical composition or a food or drink product.

[0013] (4) Composition According to one embodiment of the present invention, there is provided a composition for use in the method according to (1) to (2) above, comprising an inhibitor of production of Lipoxin A4, 5,6-EET, 17-HDHA, 10,11-EpDPA, 8,9-EpETE, 14,15-EpETE, or 15-HETrE. The composition may be a pharmaceutical composition or a food or drink product.

[0014] (5) Kit According to one embodiment of the present invention, there is provided a kit comprising the composition according to (3) to (4) above. The kit may comprise, for example, an instruction manual, a buffer, a container, or packaging. According to another embodiment, there is provided a kit for use in the treatment of neuropathic pain, wherein the kit comprises an inhibitor of production of Lipoxin A4, 5,6-EET, 17-HDHA, 10,11-EpDPA, 8,9-EpETE, 14,15-EpETE, or 15-HETrE.

[0015] (6) Use According to one embodiment of the present invention, the use of a production inhibitor of Lipoxin A4, 5,6-EET, 17-HDHA, 10,11-EpDPA, 8,9-EpETE, 14,15-EpETE, or 15-HETrE is provided for the manufacture of the compositions described in (3) to (4) above.

[0016] In one embodiment of the present invention (for example, (1) to (6) above), "lipid metabolites" include lipid degradation products produced in living organisms by enzyme-dependent oxidation or enzyme-independent oxidation. Examples of lipid metabolites include arachidonic acid metabolites, linoleic acid metabolites, dihomo-γ-linolenic acid metabolites, eicosapentaenoic acid metabolites, or docosahexaenoic acid metabolites. Examples of lipid metabolites include arachidonic acid metabolites (for example, arachidonic acid metabolites (for example, PGH2, PGE2, 15-keto-PGE2, 13,14-dihydro-15-keto-PGE2, 20-hydroxy-PGE 2、 PGD2, 15-deoxy-delta-12,14-PGJ2, PGI2, 6-keto-PGF 1α ,6,15-diketo-13,14-dihydro-PGF 1α(12-Hydroxyheptadeca trienoic acid, TXA2, TXB2), cytochrome p450 metabolites of arachidonic acid (e.g., 20-HETE, 5,6-EET), lipoxygenase metabolites of arachidonic acid (e.g., 5-lipoxygenase metabolites such as 5-HETE, 12-lipoxygenase metabolites such as 12-HETE, 15-lipoxygenase metabolites such as 15-HpETE, 15-HETE, 15-KETE, Lipoxin A4), enzyme-independent oxidative metabolites of arachidonic acid), linoleic acid metabolites (e.g., lipoxygenase metabolites of linoleic acid (e.g., 15-lipoxygenase metabolites such as 9-HODE, 13-HODE)), dihomo-γ-linolenic acid metabolites (e.g., lipoxygenase metabolites of dihomo-γ-linolenic acid metabolites) Examples include metabolites (e.g., 15-lipoxygenase metabolites such as 15-HETrE), eicosapentaenoic acid metabolites (e.g., cytochrome p450 metabolites of eicosapentaenoic acid such as 8,9-EpETE and 14,15-EpETE), docosahexaenoic acid metabolites (e.g., lipoxygenase metabolites of docosahexaenoic acid (e.g., 15-lipoxygenase metabolites such as 17-HDHA, cytochrome p450 metabolites of docosahexaenoic acid (e.g., 10,11-EpDPA)), arachidonoylethanolamide, or oleoylethanolamide, preferably characterized in that the concentration in a biological sample of a subject with neuropathic pain is significantly higher than the concentration in a biological sample of a healthy subject.

[0017] In one embodiment of the present invention (for example, (1) to (6) above), "Lipoxin A4" may also be written as LXA4. This compound may also be written as (5S,6R,7E,9E,11Z,13E,15S)-5,6,15-trihydroxyicosa-7,9,11,13-tetraenoic acid. This compound may have the structure of the compound with CAS registry number 89663-86-5.

[0018] In one embodiment of the present invention (for example, (1) to (6) above), "5,6-EET" can also be expressed as (±)5,6-EpETrE, 5,6-epoxy-8Z,11Z,14Z-eicosatrienoic acid, or 5,6-epoxyeicosatrienoic acid. This compound can also be expressed as 4-[3-[(2Z,5Z,8Z)-tetradeca-2,5,8-trienyl]oxiran-2-yl]butanoic acid. This compound may have the structure of the compound with CAS registry number 87173-80-6.

[0019] In one embodiment of the present invention (for example, (1) to (6) above), "17-HDHA" can also be written as 17-HDoHE, 17-hydroxy-DHA, 17-Hdhe, or 17-Hydroxydocosahexaenoic acid. This compound can also be written as (4Z,7Z,10Z,13Z,15E,19Z)-17-hydroxydocosa-4,7,10,13,15,19-hexaenoic acid. This compound may have the structure of the compound with CAS registry number 90780-52-2.

[0020] In one embodiment of the present invention (for example, (1) to (6) above), "10,11-EpDPA" can also be written as (±)10(11)-EpDPA or (±)10,11-epoxy Docosapentaenoic Acid. This compound can also be written as (4Z,7Z)-9-[(2S,3R)-3-[(2Z,5Z,8Z)-undeca-2,5,8-trienyl]oxiran-2-yl]nona-4,7-dienoic acid. This compound may have the structure of the compound with CAS registry number 895127-65-8.

[0021] In one embodiment of the present invention (for example, (1) to (6) above), "8,9-EpETE" can also be written as (±)8,9-epoxy Eicosatetraenoic Acid. This compound can also be written as 7-[3-(Undeca-2,5,8-trien-1-yl)oxiran-2-yl]hept-5-enoic acid. This compound may have the structure of the compound with CAS registry number 851378-93-3.

[0022] In one embodiment of the present invention (for example, (1) to (6) above), "14,15-EpETE" can also be expressed as (±)14(15)-EpETE or 14(15)-Epoxy-5Z,8Z,11Z,17Z-eicosatetraenoic acid. This compound can also be expressed as (5Z,8Z,11Z)-13-[(2S,3R)-3-[(Z)-pent-2-enyl]oxiran-2-yl]trideca-5,8,11-trienoic acid. This compound may have the structure of the compound with CAS registry number 131339-24-7.

[0023] In one embodiment of the present invention (for example, (1) to (6) above), "15-HETrE" can also be written as 15-hydroxy-8Z,11Z,13E-eicosatrienoic acid. This compound can also be written as (8Z,11Z,13E)-15-hydroxyicosa-8,11,13-trienoic acid. This compound may have the structure of the compound with CAS registry number 92693-02-2.

[0024] In one embodiment of the present invention (for example, (1) to (6) above), “neuropathic pain” is typically defined as “pain caused by lesions or diseases of the somatosensory nervous system.” It occurs when there are lesions or diseases in any of the noxious information transmission pathways from the peripheral nerves to the cerebrum, and the mechanism involves hypersensitivity of the somatosensory nervous system and weakening of the inhibitory function of the descending pain-modulating system. In embodiments of the present invention (for example, (1) to (6) above), neuropathic pain may be caused by, for example, nutritional metabolic, traumatic, ischemic, toxic, hereditary, infectious, compressive / constrictive, immunological, or degenerative diseases. Neuropathic pain may be associated with, for example, osteoarthritis, sciatica, lumbago, postherpetic neuralgia, trigeminal neuralgia, or diseases listed in Table 1 (quoted from the Japanese Society of Pain Clinics, Revised 2nd Edition Guidelines for Pharmacotherapy of Neuropathic Pain). [Table 1] JPEG2026144104000002.jpg108165

[0025] In one embodiment of the present invention (for example, (1) to (6) above), the form of the "inhibitor" is not particularly limited and may be, for example, a small molecule compound (e.g., including a small molecule organic compound), a polynucleotide (e.g., including RNA chains and DNA chains), an antibody, or a polypeptide (e.g., including an enzyme), or a composition containing the same. The small molecule compound can be obtained, for example, by FDA library screening. Alternatively, it can be obtained by utilizing combinatorial chemistry or HTS (high-throughput screening). For combinatorial chemistry, for example, an automated synthesizer L-COS series (Shoko Scientific Co., Ltd.) may be used. For HTS, for example, an Octet system (ForteBio Corporation) may be used. Alternatively, the small molecule compound may be a PROTAC (Proteolysis Targeting Chimera: a compound that induces targeted protein degradation).

[0026] In one embodiment of the present invention (for example, (1) to (6) above), the inhibitor of Lipoxin A4, 5,6-EET, 17-HDHA, 10,11-EpDPA, 8,9-EpETE, 14,15-EpETE, or 15-HETrE production may be a 5-lipoxygenase inhibitor, a 15-lipoxygenase inhibitor, or a CYP inhibitor. From the perspective of more effectively suppressing neuropathic pain, for example, Nordihydroguaiaretic acid (NDGA), PD146176 (CAS number: 4079-26-9), ML351 (CAS number: 847163-28-4), CI-986 (CAS number: 130116-16-4), BWA4C (CAS number: 106328-57-8), PD404182 (CAS number: 72596-74-8), Caffeic acid (CAS number: 331-39-5), Zileuton (CAS number: 111406-87-2), α-Tocopherol (CAS number: 10191-41-0), Trolox (CAS number: 53188-07-1), Methoxylated flavones or pharmaceutically acceptable salts thereof, or solvates thereof may be used. Alternatively, Lipoxin may be used. Inhibitors of A4, 5,6-EET, 17-HDHA, 10,11-EpDPA, 8,9-EpETE, 14,15-EpETE, or 15-HETrE production include Resveratrol (CAS No.: 501-36-0), Curcumin (CAS No.: 458-37-7), Baicalein (CAS No.: 491-67-8), Epigallocatechin gallate (CAS No.: 989-51-5), Quercetin (CAS No.: 849061-97-8), Apigenin (CAS No.: 520-36-5), Luteolin (CAS No.: 491-70-3), and Ginkgolic. The substances may be acids (CAS No. 22910-60-7), Hesperidin (CAS No. 520-26-3), Naringenin (CAS No. 480-41-1), or pharmaceutically acceptable salts thereof, or solvates thereof.Furthermore, inhibitors of Lipoxin A4, 5,6-EET, 17-HDHA, 10,11-EpDPA, 8,9-EpETE, 14,15-EpETE, or 15-HETrE production may be excluded from NDGA.

[0027] In one embodiment of the present invention (for example, (1) to (6) above), the step of identifying a target may include a step of identifying a target as a target for treatment, or a step of identifying a target as a target to be administered a pharmaceutical composition or to be given food or beverages to ingest. The step of identifying a target may include a step of selecting a target or a step of identifying a target.

[0028] In one embodiment of the present invention (for example, (1) to (6) above), the treatment includes exerting an effect that brings about a beneficial outcome for the patient with respect to the patient's disease or one or more symptoms associated with the disease (e.g., neuropathic pain) (e.g., improvement, reduction, relief, cure, remission, or suppression (e.g., prevention of onset (e.g., prevention), suppression of progression, or suppression of recurrence)). The treatment or method may be carried out by administering or ingesting an effective amount (e.g., a therapeutically effective amount) of a lipid metabolite production inhibitor to the target. In one embodiment of the present invention (for example, (1) to (6) above), the pharmaceutical composition or food or beverage includes, for example, an active ingredient and a pharmaceutically acceptable substance The active ingredient may be mixed with one or more carriers and manufactured by any method known in the art of pharmaceutical formulation. The pharmaceutical composition is not limited in form of use as long as it is used for therapeutic purposes, and may be the active ingredient alone or a mixture of the active ingredient and any other component. The form of the carrier is not particularly limited, and may be solid or liquid (e.g., buffer solution). The amount of the carrier may be, for example, a pharmaceutically effective amount. The pharmaceutically effective amount may be, for example, a sufficient amount for the pharmaceutical stability or delivery of the active ingredient. The dosage or intake may be, for example, 0.01 to 200 per dose. The dose may be mg / kg body weight. The pharmaceutical composition or food / beverage may contain stabilizers, buffers, or pH adjusters. The dosage, administration interval, method of administration, and route of administration of the pharmaceutical composition are not particularly limited and can be appropriately selected depending on the patient's age, weight, symptoms, target organ, etc. Furthermore, it is preferable that the pharmaceutical composition or food / beverage contains a therapeutically effective dose or an effective dose of the active ingredient that exerts the desired effect. In one embodiment of the present invention (for example, (1) to (6) above), the effective dose includes the amount necessary for clinically observed improvement of symptoms in the patient. In one embodiment of the present invention (for example, (1) to (6) above), pharmaceutically acceptable includes a state suitable for use in proportion to a reasonable benefit / risk ratio within the range of reasonable medical judgment. There are no particular limitations on components other than lipoxygenase inhibitors in the pharmaceutical composition or food / beverage, as long as they do not impair the effects of the present invention, and can be appropriately selected depending on the purpose.

[0029] In one embodiment of the present invention (for example, (1) to (6)), food and beverages may be food or beverage products. Food and beverages include those that can be taken orally, and include, for example, general food and beverages, as well as foods for specified health uses, nutritional supplements, functional foods, foods for the sick, etc. Food and beverages may be in the form of supplements, for example. Food and beverages may contain additives such as flavorings, colorings, or preservatives. In the production method of food and beverages, known methods may be used as appropriate depending on the type of food and beverage. Food and beverages may also be made from ingredients such as, for example, plants of the Larrea genus containing Nordihydroguaiaretic acid (NDGA), red wine and grapes containing resveratrol, turmeric containing curcumin, scutellaria containing baicalein, green tea containing epigallocatechin gallate (EGCG), onions, apples, and broccoli containing quercetin, celery and parsley containing apigenin, chamomile and bell peppers containing luteolin, ginkgo biloba containing ginkgolic acids, citrus fruits containing hesperidin, or grapefruit containing naringenin.

[0030] In one embodiment of the present invention (for example, (1) to (6) above), the subject (including patients) may be, for example, a subject who requires treatment for neuropathic pain. Subjects requiring treatment for neuropathic pain may include, for example, a subject diagnosed with neuropathic pain, or a subject suspected of developing neuropathic pain. The subject may be, for example, a subject in which a neuropathic pain marker is detected in a biological sample, or a subject in which the neuropathic pain marker in a biological sample is increased compared to a control subject (for example, a healthy person). The neuropathic pain marker may be, for example, Lipoxin A4, 5,6-EET, 17-HDHA, 10,11-EpDPA, 8,9-EpETE, 14,15-EpETE, or 15-HETrE. For example, the subject may be a subject who has experienced neuropathic pain. The subject may be, for example, a subject whose numerical rating scale (NRS) is specifically, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. The subjects may be, for example, those whose visual analog scale scores are within the range of 1, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, or any two of the numbers exemplified herein. The subjects may also be those screened using, for example, the neuropathic pain screening questionnaire described in the "Guidelines for Pharmacological Therapy of Neuropathic Pain, Revised 2nd Edition (Japanese Society of Pain Clinics)", painDETECT Japanese version, LANSS, S-LANSS, NPQ, DN4, ID pain, painDETECT, or StEP. The subjects may include humans or non-human mammals (e.g., one or more species such as mice, guinea pigs, hamsters, rats, rabbits, pigs, sheep, goats, cattle, horses, cats, dogs, marmosets, monkeys, or chimpanzees).

[0031] In one embodiment of the present invention (for example, (1) to (6) above), "biological sample" means a sample separated from a living organism, and includes, for example, bodily fluids such as blood (including plasma), urine, saliva, nasal secretions, sweat, tears, feces, and cerebrospinal fluid.

[0032] In one embodiment of the present invention (for example, (1) to (6) above), the salt is not particularly limited and includes, for example, inorganic salts or organic salts (see, for example, Bharate et al., Drug Discov Today. 2021 Feb;26(2):384-398. or Berge et al., J Pharm Sci. 1977 Jan;66(1):1-19.). Salts include, for example, metal salts, ammonium salts, salts with organic bases, salts with inorganic acids, salts with organic acids, salts with basic or acidic amino acids, etc. Metal salts include, for example, alkali metal salts (sodium salts, potassium salts, etc.), alkaline earth metal salts (calcium salts, magnesium salts, barium salts, etc.), aluminum salts, etc. Salts with organic bases include, for example, salts with trimethylamine, triethylamine, pyridine, picoline, 2,6-lutidine, ethanolamine, diethanolamine, triethanolamine, cyclohexylamine, dicyclohexylamine, N,N'-dibenzylethylenediamine, etc. Salts with inorganic acids include, for example, salts with hydrochloric acid, hydrobromic acid, nitric acid, sulfuric acid, phosphoric acid, etc. Salts with organic acids include, for example, salts with formic acid, acetic acid, trifluoroacetic acid, phthalic acid, fumaric acid, mesylic acid, tosylic acid, oxalic acid, tartaric acid, maleic acid, citric acid, succinic acid, malic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, etc. Salts with basic amino acids include, for example, salts with arginine, lysine, ornithine, etc. Salts with acidic amino acids include, for example, salts with aspartic acid, glutamic acid, etc. Salts include pharmaceutically acceptable salts. In one embodiment of the present invention (for example, (1) to (6) above), "pharmaceutically acceptable" includes a form that has reasonable benefit for pharmaceutical use. In one embodiment of the present invention (for example, (1) to (6) above), a form of a compound or a salt thereof includes a solvate thereof. In one embodiment of the present invention (for example, (1) to (6) above), a solvate includes a form of a compound formed by a solute and a solvent (see, for example, Healy et al., Adv Drug Deliv Rev. 2017 Aug 1;117:25-46).The solvates are not particularly limited, but include, for example, hydrates (e.g., monohydrates, dihydrates, trihydrates, etc.) or organic solvent hydrates (e.g., solvates with alcohols (methanol, ethanol, propanol, etc.), acetone, dimethylformamide, or ethyl acetate, etc.). The solvent includes solvents capable of substantially maintaining the physiological activity of the solute after the formation of the solvate. The solvates include pharmaceutically acceptable solvates.

[0033] In one embodiment of the present invention (for example, (1) to (6) above), "significantly" may mean, for example, a state in which statistical significance is assessed using Student's t-test (one-sided or two-sided) and p < 0.05 or p < 0.01. Alternatively, it may mean a state in which a substantial difference exists.

[0034] All publications and substance identification numbers cited herein are incorporated herein by reference in their entirety, as well as their associated structure and information. In this specification, “or” is used when “at least one” of the items listed in the text may be adopted. The same applies to “or.” In this specification, terms of the form “at least one of A, B, and C” mean that any of (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C) may be adopted. In this specification, when “within the range of two values” is specified, that range includes the two values ​​themselves. In this specification, “A to B” includes A and B and the values ​​that fall between A and B. In this specification, “a,” “an,” and “the” may be intended to indicate that there may be one or more elements or processes unless it is clearly not the case in the context. In this specification, “having” includes having a disease when relating to a disease. In this specification, “(1) to (6) above” includes references to one or more of (1), (2), (3), (4), (5), or (6).

[0035] Although embodiments of the present invention have been described above, these are merely examples of forms that may be included in the present invention, and the present invention is not limited to these, and various other configurations can be adopted. Furthermore, the present invention can be adopted by combining or independently the configurations or features described in the above embodiments. [Examples]

[0036] The present invention will be further explained below with reference to examples, but is not limited to these.

[0037] Example 1: Comprehensive concentration measurement of lipid metabolites in a rat model of arthritis Experimental method Construction of a rat model of arthritis Seven-week-old male SD rats were administered 3 mg of monoiodoacetic acid (MIA; Sigma-Aldrich, MO, USA) intra-articularly. The von-Frey test (Deusis, Front. Mol. Neurosci., 2017), in which a filament is pressed against the sole of the foot, was used to evaluate hyperalgesia symptoms to mechanical stimulation. The results showed that the threshold for avoidance behavior in the osteoarthritis group was lowered (Figure 1). Furthermore, the incapacitance test, which measures the weight distributed across both feet, was used to evaluate the imbalance in weight bearing due to pain. The results showed that the proportion of weight bearing on the affected limb was reduced in the osteoarthritis group (Figure 2). Based on these findings, an osteoarthritis model was established.

[0038] Tissue sample collection Six weeks after the onset of arthritis, subpatellar adipose tissue (IFP) and dorsal root ganglia (DRG) were collected under isoflurane inhalation anesthesia. The collected tissues were stored at -80°C until analysis. Subpatellar adipose tissue is known to be involved in the pathogenesis of arthritis, and dorsal root ganglia play an important role in pain transmission. In this study, the lumbar dorsal root ganglia projecting to the hind limb were used for analysis.

[0039] Comprehensive lipid analysis by LC-MS / MS After crushing IFP or DRG samples with a masher, lipids were extracted using the Bligh-Dyer method. Specifically, 500 μL of methanol, 200 μL of 0.1 M acetic acid, and 250 μL of chloroform were added to the crushed sample and mixed thoroughly, then allowed to stand on ice for 10 minutes. Further 250 μL of chloroform and 250 μL of ultrapure water were added, and the mixture was centrifuged at 2,000 × g for 10 minutes at 4°C. The lower layer was separated and evaporated, then resuspended in 50 μL of methanol and mixed with 750 μL of 1% formic acid solution and 10 μL of internal standard solution. This mixed solution was subjected to a solid-phase extraction cartridge (OASIS μElution plate (Waters, MA, USA)) pre-treated with 200 μL of methanol and distilled water.

[0040] After washing with 200 μL of distilled water and 200 μL of hexane, the lipid fraction of the DRG or IFP sample was eluted with 50 μL of methanol. The eluted sample solution was filtered through an Ultrafree-MC Centrifugal Filter (Merck KGaA, Darmstadt, Germany). The recovered analyte was used for measurement.

[0041] 5 μL of analyte was injected into a high-performance liquid chromatograph (Nexera 2, Shimadzu, Kyoto, Japan) equipped with a mass spectrometer (LCMS-8060, Shimadzu). 196 lipid mediators were measured and analyzed using Method Package for Lipid Mediators Version 3 with LabSolutions software (Shimadzu). Each lipid was identified by retention time and selected reaction monitor ion transitions. The level of each lipid mediator in the sample was evaluated by comparing the peak area ratio calculated by the following formula: peak area of ​​each metabolite / peak area of ​​the internal standard.

[0042] statistical analysis All statistical analyses were performed using XLSTAT Life Science (version 2021.2.2.1141, Addinsoft, Paris, France), an add-in for MS Excel (Microsoft Corporation, Redmond, Washington, US). Kruskal-Wallis tests, Steel-Dwass multiple comparison tests, and Pearson correlation analysis were used for comparisons between groups. The significance level was set at p-value < 0.05 for all statistical comparisons.

[0043] immunological staining The dorsal root ganglia of a rat model of arthritis were immunostained with anti-15-lipoxygenase antibody.

[0044] result The results are shown in Figures 3-6. The vertical axis of the graphs represents the difference in measurements between the foot with and without arthritis. In the subpatellar adipose tissue, major inflammatory mediators and their metabolites, such as the cyclooxygenase (COX) metabolites PGE2 and PGI2·TXA2 of arachidonic acid (an omega-6 fatty acid), were significantly increased or tended to increase in the arthritis group (Figure 3). This may reflect the inflammatory pathology caused by the induction of arthritis. On the other hand, increases were also observed in lipoxygenase (LOX) metabolites, not just cyclooxygenase metabolites. For example, 15-HETE, a 15-lipoxygenase metabolite of arachidonic acid, and its precursors and metabolites were significantly increased or tended to increase in the arthritis group (Figure 4). Furthermore, in the dorsal root ganglia, the cyclooxygenase metabolite PGE2 and downstream lipids were decreased, while the production of 15-HETrE, a 15-lipoxygenase metabolite of dihomo-γ-linolenic acid, tended to increase in the arthropathy group (Figure 5). Immunohistochemical staining also confirmed 15-lipoxygenase expression in the DRG (Figure 6). Based on the above, it is suggested that increased production of 15-lipoxygenase metabolites is involved in the pathogenesis of arthropathy.

[0045] Example 2: Ca2+ Measurement of TRPV1 activity by imaging We investigated the activating effect of 51 lipid metabolites on TRPV1 channels, which are primarily expressed in nerves and are responsible for pain transmission. Experimental method HEK293T cells were transfected with the mouse TRPV1 gene. After incubation for 40 minutes with Fura-2 and AM (calcium ion indicator), 3 μM of each of 51 different lipids was added to each well, and the fluorescence intensity (Ex. 380 nm, Ex. 340 nm, Em. 510 nm) was measured using a fluorescence imaging system (AQUACOSMOS; Hamamatsu Photinics, Shizuoka, Japan). An intracellular calcium concentration curve was created with the X axis as time (minutes) and the y axis as the normalized fluorescence intensity ratio at 340 / 380 nm excitation, and the AUC value of the intracellular calcium concentration curve 1 to 4 minutes after lipid addition was quantified.

[0046] result The results for cyclooxygenase metabolites are shown in Figure 7, and the results for lipoxygenase metabolites and cytochrome p450 (CYP) metabolites are shown in Figure 8. Compared to Vehicle, an increase in AUC was observed for many metabolites, but in particular, 9-HODE, 13-HODE, 12-HETE, 15-HETE, Lipoxin A4, 20-HETE, 5,6-EET, 17-HDHA, 10,11-EpDPA, 8,9-EpETE, 14,15-EpETE, 15-HETrE, OEA, and AEA had AUC > 20, indicating high TRPV1 channel activation activity. For example, compared to Vehicle, the cyclooxygenase metabolite PGE2 showed only a small amount of Ca 2+ While the concentration increased, the lipoxygenase metabolites 15-HETE and 15-HETrE showed significant Ca 2+ An increase in concentration was observed (Figure 9). Significant Ca was observed with the addition of 15-HETrE. 2+ Since the increase in concentration was canceled in cells that had not been gene-transfected (Figure 9), it is possible that 15-HETrE also has activity on the TRPV1 channel. Based on the above findings, Lipoxin A4, 5,6-EET, 17-HDHA, 10,11-EpDPA, 8,9-EpETE, 14,15-EpETE, or 15-HETrE were newly identified as lipid metabolites with high TRPV1 channel activating activity, and it was suggested that inhibiting the production of these lipid metabolites may suppress the symptoms of neuropathic pain.

[0047] Example 3: Drug administration to a rat model of arthritis Experimental method A rat model of arthritis was prepared in the same manner as in Example 1. Thirty-five days after the induction of arthritis, a vehicle, NDGA (Nordihydroguaiaretic Acid) 40 mg / kg (a non-selective lipoxygenase inhibitor), or the opioid analgesic tramadol 10 mg / kg were administered intraperitoneally. The von Frey test and incapacitance test were performed immediately before administration and 30 minutes after administration. In addition, seven days after drug administration, subpatellar adipose tissue and dorsal root ganglia were collected, and lipid metabolites were analyzed in the same manner as in Example 1.

[0048] result In the Von Frey trial, NDGA did not show a significant change (Figure 10), but it significantly improved the load imbalance measured by the Incapaciance trial (Figure 11). In addition, most of the lipid metabolites that were elevated in the arthropathy model were reduced by the administration of NDGA or Tramadol (Figures 12 and 13). The above findings suggest that inhibiting the production of lipid metabolites suppresses the symptoms of neuropathic pain.

[0049] The present invention has been described above based on examples. These examples are merely illustrative, and it will be understood by those skilled in the art that various modifications are possible, and that such modifications also fall within the scope of the present invention.

Claims

1. A composition for use in the treatment of neuropathic pain, comprising an inhibitor of the production of Lipoxin A4, 5,6-EET, 17-HDHA, 10,11-EpDPA, 8,9-EpETE, 14,15-EpETE, or 15-HETrE.

2. A composition for use in the treatment of neuropathic pain, comprising an inhibitor of Lipoxin A4, 17-HDHA, or 15-HETrE production.

3. A composition for use in the treatment of neuropathic pain, comprising Nordihydroguaiaretic acid, PD146176, ML351, CI-986, BWA4C, PD404182, Caffeic acid, Zileuton, α-Tocopherol, Trolox, Methoxylated flavones, Resveratrol, Curcumin, Baicalein, Epigallocatechin gallate, Quercetin, Apigenin, Luteolin, Ginkgolic acids, Hesperidin, Naringenin, or pharmaceutically acceptable salts thereof, or solvates thereof.

4. A composition for use in the treatment of neuropathic pain, comprising Nordihydroguaiaretic acid, PD146176, ML351, CI-986, BWA4C, PD404182, Caffeic acid, Zileuton, α-Tocopherol, Trolox, Methoxylated flavones, or pharmaceutically acceptable salts thereof, or solvates thereof.

5. The composition according to any one of claims 1 to 4, wherein the neuropathic pain is associated with osteoarthritis, sciatica, lower back pain, postherpetic neuralgia, or trigeminal neuralgia.

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