JP7701795B2 - Agent for improving age-related hyposmia - Google Patents

Description

The present invention relates to an agent for improving age-related hyposmia.

Like other senses such as sight and hearing, the sense of smell gradually declines with age. Age-related loss of smell not only makes it difficult to detect and avoid dangerous odors such as food spoilage and gas leaks, but it also significantly reduces quality of life (QOL) and has adverse physical and mental effects.

After entering the nasal cavity, odorants dissolve in the olfactory mucus in the olfactory cleft and are recognized by olfactory receptors in the olfactory nerve cells expressed in the olfactory epithelium. The olfactory receptors bind to odorants and activate them, causing electrical excitation in the olfactory nerve cells. This electrical excitation is transmitted to the higher brain via neural connections, and the odor is perceived.
Causes of smell loss include nasal congestion, which blocks the passage of odorants to olfactory nerve cells, post-cold smell loss, which causes abnormalities in the olfactory tissue due to inflammation or infection, and central (nerve, brain) smell loss caused by damage to the olfactory pathway within the skull. It has also been revealed that smell loss can appear as a precursor to neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease.
It has also been reported that various changes occur in the tissues of the olfactory system with age, which are related to the cause of a decreased sense of smell. Histological changes in the olfactory epithelium include the disappearance of olfactory nerve cells and basal cells that differentiate into olfactory nerve cells, which are replaced by respiratory epithelial tissue (Non-Patent Document 1). It has been reported that in mice, the site of olfactory epithelium degeneration coincides with the site of histological degeneration of the Bowman's gland, which produces olfactory mucus in the lamina propria mucosa (Non-Patent Document 2).

However, although it has been reported in, for example, Non-Patent Document 3 that olfactory training, in which elderly people are continuously exposed to several odors to stimulate their sense of smell, can prevent the decline in olfactory sense associated with aging, there is currently no known effective method for improving age-related olfactory decline in a short period of time.

J Neurosci, 2018 38(31): 6806-6824 Cell and Tissue Research, 2009 335: 489-503 J Am Geriatrics Soc, 2014 62(2): 384-386

The present invention relates to providing an agent for improving age-related hyposmia that improves the hyposmia associated with aging in a short period of time.

The first step in odor perception is the dissolution of odorants into olfactory mucus. The inventors have focused on olfactory mucus secretion and conducted extensive research, finding that age and olfactory mucus volume show a significant negative correlation, and that olfactory mucus secretion declines with age, which is one of the factors that cause age-related hyposmia. The inventors have then investigated methods for increasing the volume of olfactory mucus or promoting the secretion of olfactory mucus in order to improve olfactory sensitivity. As a result, they have found that by having elderly people inhale water particles or water vapor into their nasal cavities before exposure to odors, olfactory sensitivity can be improved based on the increase in the volume of olfactory mucus or the promotion of olfactory mucus secretion, and hyposmia can be improved.

That is, the present invention provides an agent for improving age-related hyposmia that contains water particles, water vapor, or a combination of these as an active ingredient and is administered by nasal inhalation.

According to the present invention, age-related loss of sense of smell can be improved by nasal inhalation of water particles or water vapor.

Correlation between age and olfactory mucus volume is shown. The correlation between the average odor sensation intensity evaluation score for an odor substance and the amount of olfactory mucus is shown. Odor sensation intensity scores and odor preference scores are shown. A schematic diagram of an apparatus for measuring the amount of water vapor generated is shown.

As shown in the Examples below, when water particles or water vapor are inhaled into the nasal cavity of elderly people using a nebulizer or steam generator before exposure to an odor, the odor identification ability and odor sensation intensity improve, and the detection threshold decreases (detection threshold score improves). Odor identification ability is the ability to distinguish the type of odor, odor sensation intensity is the strength of odor perception, and odor detection threshold is the minimum concentration at which the presence of an odor can be detected.
When human olfactory mucus volume was measured, it was found to decrease with age, and a significant negative correlation was observed between age and olfactory mucus volume (Figure 1). In addition, a significant positive correlation was observed between the mean odor sensation intensity rating for odorants and olfactory mucus volume (Figure 2). These results indicate that olfactory mucus secretion decreases with age, which is one of the factors that cause age-related hyposmia.
It has been proven by an in vitro experiment using a nasal model that water particles reach the olfactory cleft by inhaling them using a nebulizer (Visualization and Quantification of Nasal and Olfactory Deposition in a Sectional Adult Nasal Airway Cast, Pharm. Res, 2016 33:1527-1541). Therefore, it is considered that the inhaled water particles reach the olfactory cleft and mix with the olfactory mucus in the olfactory mucosa, increasing the amount of olfactory mucus. It is also known that the humidity in the nasal cavity increases according to the humidity of the inhaled air (The Role of the Nasal Cavity and Paranasal Sinuses in Biodefense, Japan Chest Clinical, 1996, Vol. 55, November Special Issue). Therefore, it is considered that the inhalation of water vapor generated from a steam generator increases the humidity in the nasal cavity, reduces the evaporation of the nasal mucus, and increases the amount of olfactory mucus.
From this, it was found that nasal inhalation of water particles, water vapor, or a combination of these prior to odor exposure increases the amount of olfactory mucus or stimulates the secretion of olfactory mucus, thereby improving olfactory sensitivity and improving hyposmia.

Therefore, the present invention provides an agent for improving age-related hyposmia, which contains water particles, water vapor, or a combination thereof as an active ingredient and is administered by nasal inhalation.The present invention also provides the use of water particles, water vapor, or a combination thereof in the manufacture of an agent for improving age-related hyposmia, which is administered by nasal inhalation.The present invention also provides the use of water particles, water vapor, or a combination thereof for improving age-related hyposmia by nasal inhalation.The present invention also provides a method for improving age-related hyposmia, which comprises nasally inhaling an effective amount of water particles, water vapor, or a combination thereof to a subject.
Here, the use of water particles or water vapor on humans may be therapeutic use, but may also be non-therapeutic use. "Non-therapeutic" is a concept that does not include medical procedures, i.e., methods of surgery, treatment, or diagnosis of humans, and more specifically, does not include methods of surgery, treatment, or diagnosis performed by a doctor, a medical professional, or a person under the instruction of a doctor.

In the present invention, the term "age-related hypoosmia" refers to a decline in olfactory function associated with aging. The olfactory function includes the ability to identify the type of odor, the ability to detect the presence of an odor, the ability to detect the strength of an odor, and the ability to distinguish between different odors.
Additionally, "improvement" refers to improvement of a symptom or condition, prevention or delay of worsening of a symptom or condition, or reversal, prevention or delay of progression of a symptom.

The types of odors perceived in the present invention are not particularly limited, and include the odors of commonly known dangerous or toxic substances (e.g., gaseous fragrances, hydrogen sulfide, chlorine gas, putrefactive matter, etc.); the odors of commonly used fragrances (e.g., animal fragrances such as musk, civet, castoreum, ambergris, etc.; plant-derived essential oils; plant-derived fragrances such as rose, jasmine, neroli, lavender, clove, peppermint, sandalwood, cinnamon, lemon, orange, bergamot, etc.); the odors of food or its ingredients; foul odors or unpleasant odors (e.g., body odor, armpit odor, bad breath, feces odor, urine odor, tobacco odor, mold odor, damp odor, putrefactive odor, food waste odor, sewage odor, exhaust odor, duct odor, exhaust gas odor, etc.); and the odors of other odorous substances (e.g., cosmetics, medicines, detergents, daily necessities, etc.).

Methods for evaluating olfactory function in humans include sensory identification tests (methods for answering the type of odor), threshold tests (methods for determining the minimum concentration at which the presence of an odor can be detected), odor intensity tests (methods for answering the intensity of odors on various scales), odor preference tests (methods for answering the preference for odors on various scales), discrimination tests (methods for selecting different odors), and intravenous olfaction tests (Alinamin test). In these tests, commercially available test kits such as Open Essence (Fujifilm Wako Pure Chemical Industries, Ltd.), T&T Olfactometer (Daiichi Pharmaceutical Industries, Ltd.), and Sniffin' Sticks (registered trademark) (Burghart Medizintechnik) may be used, or molecules that exhibit odors such as fragrances may be used alone or in mixtures, diluted as appropriate.

In the present invention, the means for inhaling water particles or water vapor through the nose is not particularly limited. Examples include a method of inhaling water particles using an inhaler capable of inhaling water particles, such as a nebulizer, and a method of inhaling water using a steam generator that generates heat and water vapor by reacting with oxygen in the air and can supply the heated water vapor to the subject.
As the nebulizer, an ultrasonic nebulizer, a mesh type nebulizer, or a compressor type nebulizer is preferably used.
The particle size of the water particles is preferably less than 10 μm, and more preferably 1 to 8 μm, where the particle size of the water particles is an effective diameter measured by a light scattering method.

The steam generator may be a known one having a water vapor generator capable of generating water vapor. For example, there is a steam generator (JP Patent Publication No. 2020-192309, JP Patent Publication No. 2020-192310, etc.) having a bottomed cylindrical mask body having an opening at the face-contacting end capable of covering the subject's nose and a water vapor generator capable of generating water vapor in the internal space of the mask body.
The steam generator preferably contains an oxidizable metal, a carbon component, and water. The oxidizable metal is a metal that generates heat of oxidation reaction by reacting with oxygen in the air, and generates steam from water by the heat generated. Examples of the oxidizable metal include powders and fibers of one or more types selected from iron, aluminum, zinc, manganese, magnesium, and calcium. Examples of the carbon component include activated carbon, acetylene black, graphite, etc., which act as a water absorbent and have water retention, oxygen supply, and catalytic properties.

In the present invention, the effective amount of water particles or water vapor is not particularly limited as long as it can improve age-related hyposmia by nasal inhalation, and can be appropriately adjusted depending on the subject's species and age, original olfactory sensitivity, nasal cavity shape, etc.
In the case of water particles, the amount sprayed per minute is preferably 0.1 mL or more, more preferably 0.5 mL or more, and is preferably 2 mL or less, more preferably 1.5 mL or less.
The time for inhaling the water particles each time is preferably 1 minute or more, more preferably 2 minutes or more, and is preferably 10 minutes or less, more preferably 7 minutes or less.

In the case of water vapor, the cumulative amount of water vapor generated that is released within 10 minutes from the start of water vapor generation (10-minute water vapor generation amount) is preferably 500 mg or more, more preferably 700 mg or more, and even more preferably 900 mg or more, and is preferably 2000 mg or less, more preferably 1700 mg or less, and even more preferably 1400 mg or less.
Here, the 10-minute water vapor generation amount is a value measured as follows using the device 30 shown in FIG.
4 includes an aluminum measurement chamber (volume 2.1 L) 31, an inflow channel 32 for introducing dehumidified air (humidity less than 2%, flow rate 2.1 L/min) into the lower part of the measurement chamber 31, an outflow channel 33 for discharging air from the upper part of the measurement chamber 31, an inlet thermometer/hygrometer 34 and an inlet flowmeter 35 provided in the inflow channel 32, an outlet thermometer/hygrometer 36 and an outlet flowmeter 37 provided in the outflow channel 33, and a thermometer (thermistor) 38 provided in the measurement chamber 31. The thermometer 38 used has a temperature resolution of about 0.01°C.

The surface temperature of the surface of the steam generator facing the skin is measured by removing the steam generator from the oxygen barrier bag at a measurement environment temperature of 30° C. (30±1° C.), placing the steam generator in the measurement chamber 31 with the surface facing the skin, i.e., the steam releasing surface, facing up, and placing a thermometer 38 with a metal ball (4.5 g) on it to measure. In this state, dehumidified air is allowed to flow from the bottom, and the difference in absolute humidity before and after the air flows into the measurement chamber 31 is calculated from the temperature and humidity measured by the inlet thermometer 34 and the outlet thermometer 36. The amount of water vapor released by the steam generator is calculated from the flow rate measured by the inlet flowmeter 35 and the outlet flowmeter 37. The total amount of water vapor measured from the time when the steam generator was removed from the oxygen barrier bag until 10 minutes later is defined as the 10-minute water vapor generation amount.
The duration of each inhalation of water vapor is preferably 5 minutes or more, more preferably 7 minutes or more, and is preferably 20 minutes or less, more preferably 15 minutes or less.

The agent for improving age-related hyposmia of the present invention can be administered by nasal inhalation according to any application schedule. Since it can immediately improve olfactory sensitivity, it is preferable to administer it to a subject before exposure to an odor. Specifically, it is preferable to administer it within 30 minutes before exposure to an odor, and more preferably within 10 minutes before exposure to an odor. Examples of administration before exposure to an odor include nasal inhalation of water particles, water vapor, or a combination thereof before cooking, eating, washing, or cleaning.
The administration period can be appropriately determined, and is, for example, preferably 1 day or more, more preferably 7 days or more, and even more preferably 30 days or more.

Targets for the agent for improving age-related hyposmia of the present invention include mammals that desire or require improvement of age-related hyposmia. Types of mammals include, for example, primates such as humans, chimpanzees, and monkeys, and rodents such as mice and rats. Primates are preferred, and humans are more preferred. Examples of humans that desire or require improvement of age-related hyposmia include those whose sense of smell has deteriorated due to aging (e.g., elderly people).

Example 1
1. Collection of olfactory mucus Thirty healthy men and women (6 in each age group, from their 20s to 60s) without subjective nasal symptoms were anesthetized with lidocaine spray, and a medical sponge (sterilized Bensheets (registered trademark) XR, 0.7 cm x 0.7 cm, Kawamoto Sangyo) was inserted into the left and right olfactory clefts (OC) and the inferior nasal meatus at four locations, and left to stand for 5 minutes. After standing, the sponge was pulled out and placed in a 1.5 mL tube, and immediately cooled under dry ice. A hole was then made with a needle at the bottom of the tube into which the sponge was inserted, and another 1.5 mL tube was placed below it, and the sponge was squeezed with a high-speed centrifuge (10,000 r/min, 10 minutes) to collect the olfactory mucus. The weight of the collected olfactory mucus was measured, and the average value of the mucus from the left and right olfactory clefts was taken as the amount of olfactory mucus for each panel. As shown in FIG. 1, when the olfactory mucus volume and age of each panel were plotted, a significant negative correlation was observed (r=-0.66, p<0.0001, Spearman's correlation).

2. Measurement of olfactory sensitivity of olfactory mucus collection panel The aforementioned 30 panel members were asked to smell six types of odor substances before and after collecting olfactory mucus, and were asked about the sensory intensity of the odors. Six types of odor substances were used: p-cresol, acetyl-p-cresol, cis-3-hexenol, cis-3-hexenyl acetate, isoborneol, and isobornyl acetate (all from Tokyo Chemical Industry Co., Ltd.). Isoborneol and isobornyl acetate were prepared as 1 v/v% solutions in mineral oil (Sigma-Aldrich), and the others were prepared as 0.1 v/v% solutions. 1 mL of each of these odor solutions was placed in a glass vial to serve as a test sample.
Each panelist smelled six different odor solutions and selected one of the following seven ratings: 1: no odor, 2: faint odor, 3: weak odor, 4: slightly strong odor, 5: strong odor, 6: very strong odor, 7: extremely strong odor.
As a result, as shown in FIG. 2, when the average sensory intensity evaluation value for each odorant before olfactory mucus collection was plotted against the amount of olfactory mucus, a significant positive correlation was observed (r=0.46, p<0.01, Spearman's correlation).
These results indicate that olfactory mucus secretion decreases with age, suggesting that this may be one of the causes of a decreased sense of smell.

Example 2 Immediate change in odor perception due to nebulizer Three types of olfactory tests were conducted before and after using a nebulizer on five healthy men and women (in their 50s and 60s, panels A to E) with no subjective nasal symptoms. The nebulizer used was an ultrasonic nebulizer NE-U07 (Omron Corporation, spray particle size: 1 to 8 μm, spray volume 1 mL/min), and Milli Q water was sprayed for 5 minutes and inhaled through the nasal cavity. The olfactory tests were of three types: (1-1) odor identification ability, (1-2) odor detection threshold, and (1-3) odor sensation intensity, and each test was conducted on a different day in a different week.

1-1. Odor Identification Ability Test Odor identification ability was measured using Open Essence (Fujifilm Wako Pure Chemical Industries, Ltd.). Five panelists sniffed 12 different odors in order and selected the odor they thought was the corresponding odor from four options (answers were chosen from six options, including odorless and unknown). A similar test was conducted after using a nebulizer at least one week after the first test.
As shown in Table 1, the number of correct answers increased in all panels after using the nebulizer compared to the first time (p<0.01, ratio paired t-test).

1-2. Odor detection threshold test The detection threshold test was performed for two types of odor substances. One was 2-phenylethyl alcohol (PEA, Tokyo Chemical Industry Co., Ltd.), with a 0.1 v/v% mineral oil solution as the most concentrated solution, and 16 solutions were prepared by sequentially diluting the solution two-fold with mineral oil. The other was Ambrettolide (Sigma-Aldrich), with an 8 v/v% mineral oil solution as the most concentrated solution, and 16 solutions with different concentrations were prepared similar to PEA. 1 mL of each of these odor solutions was placed in a glass vial and used as a test sample. The detection thresholds of PEA and Ambrettolide were measured on different days of the week.
The test was first conducted by having the subject smell the weakest odor solution and two blank solutions (mineral oil only), and then selecting the vial that seemed to contain the odor solution. If the subject answered correctly, the same concentration was used for the evaluation again, and if the subject answered correctly twice in a row, the threshold score for the first run was determined. If the subject answered incorrectly, the concentration of the odor solution was increased in order until the subject answered correctly twice in a row. The second run was conducted from a solution that was four steps stronger than the concentration at which the subject answered correctly in the first run, and the solution was diluted as long as the subject answered correctly twice in a row. Finally, the concentration at which the subject answered correctly twice in a row was determined as the threshold score for the second run. Next, the test was conducted in the same manner as the first run, starting from a solution that was five steps stronger than the score concentration in the second run, and the score was determined as the score for the third run. The fourth run was conducted from a solution that was four steps stronger than the score concentration in the third run, in the same manner as the second run. The score for the weakest concentration was "15," the score for the strongest concentration only was "0," and the score for not being able to smell the strongest concentration was also treated as "0." The average of the four runs was taken as the threshold score.
After the first detection threshold measurement, the nebulizer was used continuously and the detection threshold test after use was performed in the same manner. In the detection threshold test for Ambrettetride, panel A was able to distinguish the solution with the lowest concentration before using the nebulizer, so the test was stopped. In addition, panel E complained of fatigue during the detection threshold test after using the nebulizer, so he was not included in the analysis.
The detection threshold scores for each panel are shown in Table 2. Although there were no statistically significant differences, there was a tendency for the use of a nebulizer to generally improve the detection threshold scores.

1-3. Odor sensory intensity For panels B-E, the sensory intensity of mineral oil solutions (1 mL of each in a glass vial) of six odor substances, p-cresol (0.01 v/v%), acetyl-p-cresol (0.1 v/v%), cis-3-hexenol (0.01 v/v%), cis-3-hexenyl acetate (0.1 v/v%), isoborneol (1 v/v%), and isobornyl acetate (1 v/v%), was evaluated (Panel A was not tested due to the test schedule).
The evaluation criteria were the same as above, with one of the following seven points being selected: 1: no sensation, 2: slight sensation, 3: weak sensation, 4: somewhat strong sensation, 5: strong sensation, 6: very strong sensation, 7: extremely strong sensation. The nebulizer was used continuously, and the sensation intensity was evaluated again after each use.
The scores for each compound by each panel are shown in Table 3. When the sensory intensity scores before and after use of the nebulizer were compared for all evaluation values, the scores were significantly improved (p<0.05, paired t-test).

Example 3: Immediate change in odor perception in healthy seniors due to a steam generating device Ten healthy men and women (in their 50s and 60s) with no subjective nasal symptoms were subjected to an evaluation of the odor sensory intensity and preference for 10 types of odors before and after 10 minutes of use of a commercially available steam generating cup (Kao Corporation, water vapor generation amount 1080 mg/10 min), which generates steam in a cup that covers the nose. The following mineral oil solutions (1 mL each in a glass vial) were used: p-cresol (0.01 v/v%), acetyl-p-cresol (0.1 v/v%), cis-3-hexenol (0.01 v/v%), cis-3-hexenyl acetate (0.1 v/v%), isoborneol (0.1 v/v%), isobornyl acetate (1 v/v%), melon scent (ingredients undisclosed, 10 ppm), and green apple scent (ingredients undisclosed, 0.1 v/v%); as well as commercially available soy sauce (2 μL soaked into filter paper and placed in a glass vial), and dashi pack (10 mg placed in a glass vial).
The odor sensation intensity was evaluated according to the same criteria as in Example 1, with one of the following seven points being selected: 1: not detectable, 2: slightly detectable, 3: weakly detectable, 4: somewhat strongly detectable, 5: strongly detectable, 6: very strongly detectable, and 7: extremely strongly detectable.

Regarding preference, the melon scent and green apple scent were scored on a 7-point scale: -3: very unpleasant, -2: unpleasant, -1: slightly unpleasant, 0: neither, 1: slightly pleasant, 2: pleasant, 3: very pleasant. The soy sauce and dashi pack scents were scored on a 7-point scale: -3: very bad, -2: bad, -1: slightly bad, 0: neither, 1: slightly tasty, 2: tasty, 3: very tasty.

As a result, as shown in Figure 3, when comparing the scores before and after using the steam generator for all sensory intensity evaluation results (N=100) and preference evaluation results (N=40), there was a significant trend for odor sensory intensity and a significant improvement in preference scores (odor sensory intensity: p=0.07, preference: p<0.01, paired t-test).

Claims (3)

An agent for improving age-related hyposmia, which has water particles, water vapor or a combination thereof as an active ingredient and is administered by nasal inhalation , wherein the dosage of the water particles is 0.1 to 2 mL in terms of the amount of sprayed per minute, and the dosage of the water vapor is 500 to 2000 mg in terms of the amount of water vapor generated over 10 minutes, and the water particles, water vapor or combination thereof does not contain a drug for treating age-related hyposmia . The agent for improving age-related hyposmia according to claim 1 , which is administered before exposure to an odor. The agent for improving age-related hyposmia according to claim 1 or 2 , which is administered using an inhaler or a steam generator.

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