JP2021017405A - Prophylactic/ameliorating agent for xeroderma pigmentosum and symptoms caused by xeroderma pigmentosum - Google Patents

Abstract

To provide prophylactic and/or ameliorating agents for xeroderma pigmentosum and symptoms caused by xeroderma pigmentosum.SOLUTION: Provided is a prophylactic and/or ameliorating agent for xeroderma pigmentosum and symptoms caused by xeroderma pigmentosum, which contains melatonin or a pharmaceutically acceptable salt thereof as an active ingredient. According to the prophylactic and/or ameliorating agent, xeroderma pigmentosum and symptoms caused by xeroderma pigmentosum, such as skin disorders, neuropathy, tumors, eye disorders, and cell disorders, can be prevented and/or treated more effectively.SELECTED DRAWING: Figure 4

Description

The present invention relates to a prophylactic and / or ameliorating agent for xeroderma pigmentosum (hereinafter, may be simply referred to as "XP") and symptoms caused by xeroderma pigmentosum. More specifically, the present invention relates to a novel preventive and / or ameliorating agent for xeroderma pigmentosum and symptoms caused by xeroderma pigmentosum, which comprises melatonin or a pharmaceutically acceptable salt thereof as an active ingredient.

Xeroderma pigmentosum is a hereditary photosensitivity disorder that is inherited in an autosomal recessive manner. XP patient skin is extremely sensitive to UV light because it congenitally lacks the ability to repair DNA damage caused by UV light, and severe photosensitivity and freckle-like pigmentation progress if not properly shaded. However, skin cancer develops frequently despite young age. In addition, more than half of XP patients are associated with unexplained progressive brain and neurodegenerative symptoms, the severity of which affects patient prognosis.

XP is divided into eight genetically distinct groups, groups A to G (genetic complementation group) and variant (V) type. In Japan's XP, group A (xeroderma pigmentosum group A: XP-A), which has the most severe skin and neurological symptoms, accounts for about 55%, and type V, which has only skin symptoms, is said to account for about 25%. Photosensitivity symptoms are severe in XP-A patients, which are common in Japanese, and severe sunburn symptoms appear immediately after birth. In addition, in XP-A patients, neurological symptoms such as hearing loss, indistinct language, and imbalance of the body became apparent from around the age of 6, and from the age of 10 onwards, in all aspects of nerves, intelligence, and body. Symptoms get worse.

There is a report of Xpa-deficient mice, which are model mice of xeroderma pigmentosum-Group A (Non-Patent Document 1). By suppressing CXCL1 (chemokine (CXC motif) ligand 1) using the model mouse described in Non-Patent Document 1, the development of ultraviolet B (UV-B) -induced skin inflammation and tumor is controlled. There is a report on this (Non-Patent Document 2). However, no effect of CXCL1 inhibition on neurological symptoms in model mice has been shown.

An oxidative stress marker, 8-hydroxy-2'-deoxyguanosine (8-OHdG), has been demonstrated in the autopsy brain of XP-A patients (Hayashi M et al., Brain Dev. 2005, 27: 34-38). XP-A patients and healthy subjects were divided into groups under 15 years old and over 15 years old, and at each time of the day, 8-OHdG, hexanoyl lysine (HEL), which are oxidative stress markers in urine samples, and hexanoyl lysine (HEL), There is a report on the measurement results of 6-sulphatoxymelatonin (6-SM), which is a melatonin metabolite (Non-Patent Document 3). In Non-Patent Document 3, 8-OHdG values and HEL values tended to be different from 6-SM values in the groups under 15 years old and over 15 years old. Melatonin is mainly metabolized in the liver. The C6 site of melatonin is hydroxylated and excreted as 6-SM in urine. Melatonin secretion generally declines with age and peaks at night are lost. So far, urinary 6-SM has been measured in patients with various developmental disorders such as autism and attention-deficit hyperactivity disorder (ADHD).

Many reports have been made on the antioxidant activity of melatonin, and it is expected to have a protective effect on nerve cells (Hardeland R et al., Edocrine 2005, Cagnoli et al., J. Pineal Res. 1995). In addition, there are multiple reports of improvement of neurological symptoms by administration of melatonin in neurodegenerative disease model animals such as Parkinson's disease, amyotrophic lateral sclerosis (ALS), and Alzheimer's disease (Di Paolo et. al., Food and Chemical Toxicology 2014, Lee MY et al., J. Pineal Res., 2007). However, there is no description or suggestion that melatonin was applied to xeroderma pigmentosum or xeroderma pigmentosum.

The basic treatment method for XP has not been established, and symptomatic treatments such as shading guidance, early detection and treatment of skin cancer, hearing aid wearing, and rehabilitation guidance are being performed. When skin cancer develops, the usual treatment for skin cancer is given, but the underlying cause specific to xeroderma pigmentosum (XP) and symptoms caused by XP can be removed or alleviated. Development of preventive / improving drugs is desired.

Nakane et al., Nature, Vol.377, 14, p.165-168, 1995 Kunisada et al., J. Investigative Dermatology (2017) 137, 1975-1983 Miyata et al., Oxidative Medicine and Cellular Longevity, Vol. 2016, Article ID 5741517

An object of the present invention is to provide a prophylactic and / or ameliorating agent for xeroderma pigmentosum and symptoms caused by xeroderma pigmentosum.

As a result of diligent studies to solve the above problems, the present inventors have prevented melatonin or a pharmaceutically acceptable salt thereof from preventing xeroderma pigmentosum and xeroderma pigmentosum. / Or found that it is effective for improvement, and completed the present invention.

That is, the present invention comprises the following.
1. 1. A prophylactic and / or ameliorating agent for xeroderma pigmentosum and symptoms caused by xeroderma pigmentosum, which comprises melatonin or a pharmaceutically acceptable salt thereof as an active ingredient.
2. 2. The prevention and / or prevention according to item 1 above, wherein the symptoms caused by xeroderma pigmentosum and xeroderma pigmentosum are one or more selected from skin disorders, neuropathy, tumors, eye disorders and cell disorders. Or an improving agent.
3. 3. The prevention and prevention according to item 2 above, wherein the skin disorder is one or more selected from edematous erythema, pigmented spots, depigmented spots, dryness and skin atrophy with blistering caused by exposure to sunlight and / or ultraviolet rays. / Or an improver.
4. The neuropathy is any one or more selected from motor dysfunction, auditory dysfunction, dysphagia, eating disorder, dysuria and respiratory disorder caused by xeroderma pigmentosum, as described in item 2 above. The preventive and / or improver described.
5. One or more tumors selected from sunlight-induced basal cell carcinoma, spinous cell carcinoma, malignant melanoma, seborrheic keratosis, photokeratosis, keratoacanthoma, angiosarcoma and fibrosarcoma The preventive and / or improver according to item 2 above, which is a species.
6. 7. The preventive and / or ameliorating agent according to item 2 above, wherein the eye disorder is one or more selected from photophobia, keratitis, skin atrophy of the eyelid, and pterygium. The prevention and prevention according to item 2 above, wherein the cell disorder is any one or more selected from cell damage of pigment cells, elevation of cell surface oxidative stress marker of pigment cells, and nerve cell damage in inner ear cochlea. / Or an improver.

According to the preventive and / or ameliorating agents for xeroderma pigmentosum and xeroderma pigmentosum, which contain melatonin or a pharmaceutically acceptable salt thereof as an active ingredient, the skin is effectively used. It is possible to prevent and / or treat xeroderma pigmentosum and symptoms caused by xeroderma pigmentosum such as disorders, neuropathy, tumors, eye disorders and cell disorders.

It is a figure which shows the result of having measured the production amount of 8-OHdG in the cultured cell after irradiation with ultraviolet rays (UV-B) about the XP fibroblast established from the skin collected from the XP-A patient. (Reference example 1) The results of measuring the amount of 8-OHdG produced when XP fibroblasts established from the skin collected from XP-A patients were cultured in a culture medium containing each antioxidant during ultraviolet (UV-B) irradiation are shown. It is a figure. (Reference example 2) Using XP patient-derived melanocytes (pigment cells) induced to differentiate from XP-iPS cells prepared from cells established from XP-A patients, the effects of antioxidants on oxidative stress caused by 4NQO and on cytotoxicity It is a figure which shows the experimental protocol for verification. (Example 1) It is a figure which shows the result about cytotoxicity when experimented with the protocol shown in FIG. Cytotoxicity was confirmed by lactate dehydrogenase (LDH) levels. (Example 1) It is a figure which shows the experimental protocol for verifying the effect of melatonin on the skin cancer formation after chronic ultraviolet irradiation in XP-A model mouse. (Example 2) It is a figure which shows the tumor number and tumor volume measurement result per individual under each condition when experimented with the protocol shown in FIG. (Example 2) It is a figure which shows the result when the hearing ability per individual was measured by the ABR threshold value at the time of the experiment by the protocol shown in FIG. (Example 3) It is the figure which verified whether the melatonin diet has the effect of reducing the ultraviolet erythema in the XP-A model mouse. (Example 4)

The present invention relates to a prophylactic and / or ameliorating agent for xeroderma pigmentosum and symptoms caused by xeroderma pigmentosum, which comprises melatonin or a pharmaceutically acceptable salt thereof as an active ingredient.

As described herein, "xeroderma pigmentosum (XP)" is a hereditary photosensitivity disease inherited in an autosomal latent form, as described in the background art section. In the present specification, XP is used in a concept that includes all eight genetically distinct groups A to G (genetic complementation group) and variant (V) type. Particularly preferably, it is applied to group A (XP-A), which has the most severe skin symptoms and neurological symptoms.

In the present specification, "symptoms caused by xeroderma pigmentosum and xeroderma pigmentosum" include skin disorders, neuropathy, tumors, eye disorders caused by xeroderma pigmentosum and xeroderma pigmentosum. Examples include cell damage. Specific examples of the skin disorder, neur disorder, tumor, eye disorder and cell disorder include the following symptoms.

“Skin disorders” include the skin of XP patients, which is extremely sensitive to UV light because it congenitally lacks the ability to repair DNA damage caused by UV light, and is highly irritated by sunlight and / or UV exposure if not properly shaded. (Erythema edema that can cause blistering and its persistence), pigmented spots, depigmented spots, dryness and skin atrophy. In particular, edematous erythema, pigmented spots, depigmented spots, dryness and skin atrophy with blistering caused by sunlight and / or UV exposure. For example, sun hypersensitivity (about 60% of patients experience severe sunburn with blistering and persistent erythema with slight sun exposure, and in the majority of patients young, prominent freckle-like pigmented spots and prolapse on the face. Pigment spots occur, and the exposed skin becomes dry, etc.). Acute symptoms of clinical photosensitivity include an abnormally high degree of sunburn-like eruption, for example, a healthy person develops severe edematous erythema with blistering due to an amount of ultraviolet light that does not tan, and the peak of inflammation is, for example, 3 For example, it will be 4 days later. It may be accompanied by chronic symptoms of clinical photosensitivity, such as characteristic pigmented spots localized to the exposed area, skin atrophy, and telangiectasia. In addition, there are brown to black-brown pigmented spots having uneven color tones and varying sizes.

Examples of the "neuropathy" include motor dysfunction, auditory dysfunction, dysphagia, eating disorder, dysuria, and respiratory disorder caused by xeroderma pigmentosum. Approximately 50% of patients with xeroderma pigmentosum (XP) have neurological symptoms (microcephaly, progressive brain / neuropathy of unknown cause (gait disturbance, progressive sensory hearing loss, ataxia), diminished deep tendon reflex) Alternatively, disappearance may occur, including dysphagia, eye disorders, urination disorders, and respiratory disorders. The severity of neurological symptoms affects the prognosis of patients.

"Tumors" are tumors caused by xeroderma pigmentosum, which have an extremely high risk of sun-induced skin tumors, sun-induced basal cell carcinoma, spinous cell carcinoma and malignant melanoma, and seborrheic. Examples include keratosis, photokeratosis, keratoacanthoma, angiosarcoma, and fibrosarcoma. The skin of patients with xeroderma pigmentosum (XP) is extremely sensitive to UV light because it congenitally lacks the ability to repair DNA damage caused by UV light, and if proper shading is not done, severe sun dermatitis, followed by freckles. Freckle-like pigmentation progresses, and eventually skin cancer develops frequently despite young age. Tumors caused by xeroderma pigmentosum are also exemplified as examples of symptoms caused by xeroderma pigmentosum.

"Eye disorders" are eye disorders caused by xeroderma pigmentosum, and include photophobia, keratitis, skin atrophy of the eyelids, and pterygium.

"Cell disorders" are cell disorders caused by pigmented psoriasis, and are disorders of pigment cells (melanocytes), elevation of cell surface oxidative stress markers of pigment cells, and intrainternal ear cochlear caused by pigmented psoriasis. Any one or more selected from the neuronal disorders of the above can be mentioned.

Melatonin is commonly known as N-acetyl-5-methoxytryptamine. Normelatonin or N-Acetylserotonin is a naturally occurring compound as an intermediate in the synthesis of melatonin from serotonin. It is produced from serotonin by the action of alkylamine-N-acetyltransferase and becomes melatonin by the action of acetylserotonin-O-methyltransferase. Like melatonin, normelatonin is an agonist of the melatonin receptors MT1, MT2, MT3 and is thought to be a neurotransmitter. Furthermore, normelatonin is distributed in specific parts of the brain where neither serotonin nor melatonin is distributed, suggesting that it not only acts as a precursor for melatonin synthesis, but also has a unique function in the central nervous system. To. 6-SM is known as a metabolite of melatonin. In the present specification, melatonin may be an active ingredient as a preventive and / or ameliorating agent for xeroderma pigmentosum and xeroderma pigmentosum, as long as it is a substance having such a function. Also included are synthetic intermediates of melatonin and melatonin metabolites. The preventive and / or ameliorating agent for xeroderma pigmentosum and xeroderma pigmentosum-induced symptoms containing melatonin of the present invention or a pharmaceutically acceptable salt thereof as an active ingredient is used as a pharmaceutical composition. To. Pharmaceutical composition means a composition suitable for administration in medical applications. Included with one or more pharmaceutically acceptable excipients. Therapeutically effective amounts of melatonin or pharmaceutically acceptable salts thereof also include other forms (eg, solvates).

As used herein, the pharmaceutically acceptable salt means a salt that does not have a harmful effect on the administration subject and does not eliminate the pharmacological activity of the active ingredient in the pharmaceutical composition, and specifically, , Hydrochloride, hydrobromic acid, hydroiodic acid, sulfuric acid, nitrate, phosphoric acid and other inorganic acids, formic acid, acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, lactic acid, apple Acids, mandelic acid, tartaric acid, dibenzoyl tartaric acid, ditor oil tartaric acid, citric acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, aspartic acid, or acid addition salts with organic acids such as glutamate, sodium, potassium, magnesium , Inorganic bases such as calcium and aluminum, salts with organic bases such as methylamine, ethylamine, ethanolamine, lysine and ornithine, salts with various amino acids such as acetylleucine and amino acid derivatives, ammonium salts and the like.

The pharmaceutical composition as a preventive and / or ameliorating agent for xeroderma pigmentosum and symptoms caused by xeroderma pigmentosum of the present invention uses a pharmaceutical carrier, excipient, etc. that are usually used in the art. It can be prepared by a commonly used method. Administration is oral administration by tablets, pills, capsules, granules, powders, liquids, etc., or injections such as intra-articular, intravenous, intramuscular, suppositories, eye drops, eye ointments, transdermal solutions, It may be in any form of parenteral administration using an ointment, a transdermal patch, a transmucosal solution, a transmucosal patch, an inhalant, or the like. As the solid composition for oral administration according to the present invention, tablets, powders, granules, sustained-release agents and the like are used. In such solid compositions, one or more active ingredients are mixed with at least one pharmaceutically acceptable excipient.

Pharmaceutically acceptable carriers herein include various commonly used organic or inorganic carrier materials as formulation materials, such as excipients, lubricants, binders and disintegrants in solid formulations, or liquid formulations. Examples thereof include solvents, solubilizing agents, suspending agents, tonicity agents and buffering agents. Further, if necessary, an appropriate amount of additives such as ordinary preservatives, antioxidants, colorants, sweeteners, adsorbents, and wetting agents can be used.

Pharmaceutically acceptable excipients herein include, for example, tonicity agents, bulking agents, preservatives / bactericides, binders, antioxidants, solubilizers, solubilizers, suspending agents, etc. Examples include fillers, pH regulators, stabilizers, absorption promoters, release rate control agents, colorants, plasticizers, adhesives and the like. Specific examples thereof include lactose, sucrose, D-mannitol, starch, cornstarch, crystalline cellulose, and light anhydrous silicic acid. Examples of the lubricant include magnesium stearate, calcium stearate, talc, colloidal silica and the like. Examples of the binder include crystalline cellulose, sucrose, D-mannitol, dextrin, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, polyvinylpyrrolidone, starch, sucrose, gelatin, methyl cellulose, sodium carboxymethyl cellulose and the like. Examples of the disintegrant include starch, carboxymethyl cellulose, calcium carboxymethyl cellulose, sodium croscarmellose, sodium carboxymethyl starch, L-hydroxypropyl cellulose and the like. Examples of the solvent include water for injection, alcohol, propylene glycol, macrogol, sesame oil, corn oil, olive oil and the like. Examples of the solubilizing agent include polyethylene glycol, propylene glycol, D-mannitol, benzyl benzoate, ethanol, trisaminomethane, cholesterol, triethanolamine, sodium carbonate, sodium citrate and the like. As suspending agents, for example, surfactants such as stearyltriethanolamine, sodium lauryl sulfate, laurylaminopropionic acid, lecithin, benzethonium chloride, glycerin monostearate; for example, polyvinyl alcohol, polyvinylpyrrolidone, sodium carboxymethylcellulose, methylcellulose, etc. Examples thereof include hydrophilic polymers such as hydroxymethyl cellulose, hydroxyethyl cellulose and hydroxypropyl cellulose. Examples of the tonicity agent include glucose, D-sorbitol, sodium chloride, glycerin, D-mannitol and the like. Examples of the buffering agent include buffer solutions such as phosphates, acetates, carbonates and citrates. Examples of preservatives include paraoxybenzoic acid esters, chlorobutanol, benzyl alcohol, phenethyl alcohol, dehydroacetic acid, sorbic acid and the like. Examples of the antioxidant include sulfites, ascorbic acid, α-tocopherol and the like.

The dose of melatonin as an active ingredient or a pharmaceutically acceptable salt thereof varies depending on the administration subject, administration route, symptom, body weight, age, etc., and is not particularly limited. For example, when orally administered to an adult patient, it is about. It can be 0.001 to about 3 mg / kg body weight, preferably about 0.005 to about 2 mg / kg body weight, more preferably about 0.01 to about 1 mg / kg body weight. It is desirable to administer these doses about 1 to 3 times a day, depending on the symptoms. Melatonin is a hormone that originally exists in animals, plants, and microorganisms, and by acting on the body clock, it has the effect of switching between awakening and sleep and inducing natural sleep, so it is possible to have a time zone that does not interfere with daily life. It can be selected and administered as appropriate.

Melatonin as an active ingredient or a pharmaceutically acceptable salt thereof may be administered in combination with other drugs as appropriate. For example, by combining melatonin as an active ingredient or a pharmaceutically acceptable salt thereof with a concomitant drug, a synergistic effect can be obtained in which the dose of each drug can be reduced as compared with the case where each drug is administered alone. It is expected that the treatment period can be set longer and the treatment effect can be sustained.

Treatment of conventional xeroderma pigmentosum and symptoms caused by xeroderma pigmentosum includes the following, but is not particularly limited in the present invention. Cryotherapy with liquid nitrogen can be used in combination with carcinoma in situ for spinous cell cancer such as actinic keratosis. Topical therapy with 5-fluorouracil ointment or imiquimod cream can also be used in combination. Skin tumors can also be treated in combination by electrocoagulation and surgical resection. Oral administration of isotretinoin or acitretin in combination can suppress the occurrence of new skin neoplasms, but there are concerns about many side effects. Surgical treatment may be performed in combination with malignant neoplasms of the eyelids, conjunctiva, and cornea. Corneal transplantation may improve vision impairment due to severe keratitis. Hearing aids may be used for deafness.

Prevention of primary lesions of xeroderma pigmentosum and symptoms caused by xeroderma pigmentosum includes the following, but is not particularly limited in the present invention. Keep skin and eyes out of sunlight and UV rays. Take vitamin D supplements as needed to prevent secondary complications. The usual follow-up is a doctor's skin examination once every 3 to 12 months, and regular ophthalmic, neurological, and hearing tests. Rehabilitation guidance for joint contracture.

By using a prophylactic and / or ameliorating agent for xeroderma pigmentosum and xeroderma pigmentosum containing melatonin of the present invention or a pharmaceutically acceptable salt thereof as an active ingredient, the above-mentioned symptoms Can be reduced, the burden of treatment can be reduced, and effective prevention can be achieved.

In order to assist the understanding of the present invention, the present invention will be specifically described with reference to Examples and Examples, but it goes without saying that the present invention is not limited thereto.

(Reference Example 1) Oxidized DNA damage in XP fibroblasts by ultraviolet irradiation In this reference example, the degree of oxidized DNA damage in XP fibroblasts was confirmed by the amount of 8-OHdG produced, which is an oxidative stress marker. 8-OHdG is a DNA oxidative damage marker with a structure in which the 8-position of deoxyguanosine (dG) is hydroxylated. Since dG has the lowest redox potential among the four types of bases in DNA, it is susceptible to oxidation by active oxygen. Therefore, 8-OHdG, which is a major oxidation product of dG, sensitively reflects the effects of active oxygen on living organisms. 8-OHdG formed on chromosomal DNA is excised from chromosomal DNA by the action of repair enzymes, released extracellularly, and excreted in urine via the kidney. Other known sources of 8-OHdG are mitochondrial DNA and intracellular nucleotide pools. 8-OHdG is a chemically stable substance and is excreted in urine without undergoing secondary metabolism, so it is used as a biomarker that quantitatively reflects oxidative stress in the body. ..

Fibroblasts established from the skin collected from XP-A group patients and healthy subjects were used. XP fibroblasts from 3 XP-A patients and 3 x 10 ⁶ cells per Petri dish were sprinkled on each of 3 healthy human fibroblasts, 2 cells per cell type, cultured for 24 hours. It was later irradiated with 800 J / m ² of ultraviolet light (UV-B) and continuously cultured for 3, 6, 9 and 24 hours. Culturing was carried out according to a conventional method using DMEM medium. After each time culture, cells were collected, DNA was extracted, and 8-OHdG production was measured by high performance liquid chromatography (HPLC). The relative amount of 8-OHdG in the cultured cells at each observation time with respect to the amount of 8-OHdG produced at the start of culturing for each cell line is shown in FIG.

As a result of the above, it was shown that the recovery of 8-OHdG level to the previous value is much slower in XP cells than in healthy human-derived cells.

(Reference Example 2) Recovery of Oxidized DNA Damage of XP Fibroblasts by Antioxidants In this Reference Example, XP fibroblasts derived from XP-A patients are cultured at 800 J / 24 hours after culturing by the same method as in Reference Example 1. Irradiated with m ² ultraviolet rays (UV-B). Catalase (Cat; Roche Diagnostics GmbH Mannheim GmbH, Manheim, Germany), superoxide dismutase (SOD; WAKO Pure Chemicals Industries, Ltd, Osaka), or deferoxamine (Df; Sigma Chemical Co. St) as antioxidants for each XP cell The cells were cultured for 24 hours using a culture solution containing .Louis, MO, USA), and the production of 8-OHdG was measured in the same manner as in Reference Example 1.

UV-B production of 8-OHdG in XP cells at the start of culture without irradiating the a 1, UV-B 800 after irradiation with J / m ² and UV-B 800 J / m 24 hours after ² culture The amount of 8-OHdG produced by the later XP cells is shown relatively in FIG.

As a result of the above, it was confirmed that the amount of 8-OHdG decreased when the cells were cultured in the culture medium to which the antioxidant was added. For XP cells, it was confirmed that antioxidants are useful for suppressing the production of 8-OHdG or eliminating the produced 8-OHdG.

(Example 1) Effect of antioxidant against oxidative stress caused by 4-nitroquinoline 1-oxide in XP cells Easily from iPS cell (induced pluripotent stem cells) strains established by a feeder-free method from cells derived from healthy humans A method for producing pigment cells (melanocytes) has been reported (Hosaka et al., Pigment cell Melanoma Res. 2019; 1-11). In this reference example, iPS cells derived from XP-A patients were established by the same method as shown by Hosaka et al., And then pigment cells (melanocytes) were prepared and used in the experiment. Pigment cells are known to be highly sensitive to radicals among many cell types existing in the body, and damage caused by radicals and their recovery can be seen with high sensitivity.

4-Nitroquinoline 1-Oxide (4NQO) has been reported to be a potent radical inducer by electron acceptance (John E. Biaglow et al., CANCER RESEARCH 37 3306-3313). , 1977). In this example, the above-prepared XP-A patient-derived pigment cells (melanocytes) and healthy human-derived pigment cells (melanocytes) were used, and anti-cytotoxicity when stimulated with 4NQO or H ₂ O ₂ according to the protocol shown in FIG. The effect of the oxidizing agent was verified. 24 hours prior to 4NQO or H ₂ O ₂ stimulation were seeded XP cells (2.5 × 10 ⁴ cells) into the dish, cultured for 24 hours, stimulated with 4NQO or H ₂ O _2. As antioxidants, melatonin, nicotinamide (NAD) and catalase were used. Each combination shown in Table 1 was stimulated with ₄ NQO or H ₂ O ₂ and treated with antioxidants.

Cytotoxicity was confirmed by the lactate dehydrogenase (LDH) level released from the cells. The LDH value was measured using the LDH Cytotoxicity Detection Kit (TAKARA). As a result, 3 μM 4NQO treatment had almost no effect on healthy human-derived pigment cells, but cytotoxicity was observed in XP patient-derived pigment cells (Fig. 4). On the other hand, cytotoxicity was suppressed by culturing the cells in a culture medium containing 50 μM melatonin as an antioxidant (Fig. 4). As shown in the protocol of FIG. 3, the cells were cultured in a culture solution containing an antioxidant such as melatonin 24 hours and 30 minutes before the radical inducer stimulation, and 20 minutes after the stimulation, the cells were replaced with the culture solution containing the antioxidant again. After that, the cells were cultured for 24 hours.

(Example 2) Effect of melatonin on skin cancer formation after chronic UV irradiation In this example, the effect of melatonin on skin cancer formation after chronic UV irradiation was verified in XP-A model mice. The XP-A model mouse is an albino hairless XP-A model prepared by the method shown in Non-Patent Document 1 (Nakane et al., Nature, Vol.377, 14, p.165-168, 1995) and further modified. Mice are used (Ito et al., J. Invest Dermatol., 2005: 125: 554-9).

According to the protocol shown in FIG. 5, XP-A model mice were fed a diet containing melatonin or N-acetylcysteine (NAC) for 4-19 weeks of age and irradiated with UV-B once a week for a total of 10 times. UV-B was irradiated at 100 mJ / cm ^{2 for} wild-type (WT) and 25 mJ / cm ^{2 for} XP-A model mice, and the number of tumors and tumor volume per individual at 36-38 weeks of age. Was measured. The dose and n number of melatonin or N-acetylcysteine (NAC) are shown in Table 2.

The number of tumors and tumor volume per individual under each condition are shown in FIG. It is known that N-acetylcysteine is used as a protective agent against oxidative stress in living organisms. From the results shown in FIG. 6, melatonin showed an excellent effect on the number of tumors and the volume of tumors at a smaller dose than N-acetylcysteine.

(Example 3) Effect of melatonin on auditory brainstem response after chronic ultraviolet irradiation Similar to Example 2, the effect of melatonin on auditory brainstem response (ABR) after chronic ultraviolet irradiation using XP-A model mice. Was verified. According to the protocol shown in FIG. 5, XP-A model mice were fed a diet containing a high dose or a low dose of melatonin for a period of 4-19 weeks in the same manner as in Example 2, and UV-B was given once a week for a total of 10 times. Irradiated. Hearing per individual at 26, 32, 36 and 44 weeks of age was confirmed by measuring the ABR threshold. It is measured using ABR, which is one of the evoked potentials of brain waves, and higher values are judged to be hearing loss. It is known that XP-A model mice have decreased hearing (increased ABR threshold) at 38-40 weeks of age compared to wild-type mice (Shinomiya et al., Frontiers in Aging Neuroscience, 10.3389 / fnagi. 2017.00019. ) However, the ABR threshold was improved by feeding low and high doses of melatonin (Fig. 7).

(Example 4) Reduction of erythema reaction by low dose of melatonin
When XP-A model mice were fed with a low-dose melatonin diet or a normal diet for 2 weeks and then irradiated with UVB 15 mJ / cm ² , erythema / desquamation 72 hours after irradiation and desquamation 96 hours after irradiation were observed in the low-dose melatonin group. There was a tendency to reduce the dose compared to the normal diet group (Fig. 8).

More effectively according to the prophylactic and / or ameliorating agents for xeroderma pigmentosum and xeroderma pigmentosum, which contain melatonin or a pharmaceutically acceptable salt thereof as an active ingredient of the present invention. It is possible to prevent and / or treat xeroderma pigmentosum and symptoms caused by xeroderma pigmentosum such as skin disorders, neuropathy, tumors, eye disorders and cell disorders.

Claims (7)

A prophylactic and / or ameliorating agent for xeroderma pigmentosum and symptoms caused by xeroderma pigmentosum, which comprises melatonin or a pharmaceutically acceptable salt thereof as an active ingredient. The prevention and prevention according to claim 1, wherein the xeroderma pigmentosum and the symptoms caused by xeroderma pigmentosum are one or more selected from skin disorders, neuropathy, tumors, eye disorders and cell disorders. / Or an improver. The prevention according to claim 2, wherein the skin disorder is one or more selected from edematous erythema, pigmented spots, depigmented spots, dryness and skin atrophy with blistering caused by exposure to sunlight and / or ultraviolet rays. And / or improver. Claim 2 that the neuropathy is any one or more selected from motor dysfunction, auditory dysfunction, dysphagia, eating disorder, dysuria and respiratory disorder caused by xeroderma pigmentosum. The preventive and / or improver described in. One or more tumors selected from sunlight-induced basal cell carcinoma, spinous cell carcinoma, malignant melanoma, seborrheic keratosis, photokeratosis, keratoacanthoma, angiosarcoma, and fibrosarcoma. The preventive and / or ameliorating agent according to claim 2, which is a species. The preventive and / or ameliorating agent according to claim 2, wherein the eye disorder is one or more selected from photophobia, keratitis, skin atrophy of the eyelids, and pterygium. The prevention according to claim 2, wherein the cell disorder is any one or more selected from cell damage of pigment cells, elevation of cell surface oxidative stress markers of pigment cells, and neuronal damage in inner ear cochlea. And / or improver.