JP7393085B2 - Method, device and program for estimating oxygen level of subcutaneous tissue, and method, device and program for estimating viscoelasticity of subcutaneous tissue or fibrosis level of subcutaneous fat cells - Google Patents

Description

The present invention provides a method, an estimation device, and an estimation program for estimating the oxygen level of the subcutaneous tissue using the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells as an index, and the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells. The present invention relates to a level estimation method, an estimation device, and an estimation program.

Skin aging phenomena associated with aging, ie, changes in appearance such as wrinkles, sagging, and age spots, are caused by physiological and chemical changes in the internal structure of the skin. In recent years, with the aim of suppressing such skin aging phenomena, there has been increasing interest in elucidating the mechanism of age-related changes in the internal structure of the skin.

The skin is roughly divided into three layers: the epidermis, the dermis, and the subcutaneous tissue. The epidermis can be further classified into four layers: the stratum corneum, the stratum granulosum, the stratum spinosum, and the stratum basale, and the underlying dermis can be classified into three layers: the papillary layer, the subpapillary layer, and the reticular layer. The subcutaneous tissue plays the role of supporting the epidermis and dermis.

Most of the subcutaneous tissue is subcutaneous fat, which is composed of adipose lobules in which fat cells form clusters, and has functions such as heat retention and buffering against external forces. Fat lobules are surrounded by connective tissue such as collagen fibers and elastin fibers in a mesh pattern, forming a fibrous structure.

In the past, palpation was used as a method to judge the hardness of the skin, but with the development of ultrasonic elastography technology (for example, Patent Document 1), the physical characteristics of each layer that makes up the skin, especially the viscosity, have been improved. Quantitative measurement of elasticity is now possible.

By the way, biological tissue diagnosis (so-called "biopsy") is generally performed as a method for pathologically diagnosing fibrosis of body tissues. However, it has been difficult to perform biopsies frequently because they involve invasion of the subject. It is disclosed that "Fibroscan" based on ultrasound elastography is capable of non-invasively evaluating liver fibrosis (Patent Document 2).

Special Publication No. 2009-539528 International publication 2011/081214 pamphlet

The problem to be solved by the present invention is to provide a novel technique that makes it possible to estimate the viscoelasticity of subcutaneous tissue or the fibrosis level of subcutaneous fat cells and the oxygen level.

As a result of intensive research, the present inventors have found that there is a correlation between the viscoelasticity of subcutaneous tissue or the fibrosis level of subcutaneous fat cells and oxygen level, and have completed the present invention.

That is, the present invention to solve the above problems utilizes the correlation between the viscoelasticity of the subcutaneous tissue or the fibrosis level of subcutaneous fat cells and the oxygen level of the subcutaneous tissue, and improves the viscoelasticity or This is a method for estimating an oxygen level, characterized in that the oxygen level is estimated using the fibrosis level of subcutaneous fat cells as an index.
According to the present invention, the oxygen level of the subcutaneous tissue can be estimated from the physical or physiological characteristics of the viscoelasticity of the subcutaneous tissue or the fibrosis level of subcutaneous fat cells.

In a preferred embodiment of the present invention, a regression equation is used in which the measured value of the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells is used as an explanatory variable, and the evaluated value of the oxygen level of the subcutaneous tissue is used as the objective variable. The oxygen level is calculated from a measured value of viscoelasticity or fibrosis level of subcutaneous fat cells.
By using a regression equation prepared in advance, the oxygen level in the subcutaneous tissue can be estimated more accurately.

A preferred embodiment of the present invention is characterized in that the viscoelasticity of the subcutaneous tissue is measured by ultrasonic elastography.
As a result, it is possible to non-invasively and quantitatively obtain a measurement result of the viscoelasticity of the subcutaneous tissue, and it is possible to estimate the oxygen level of the subcutaneous tissue with higher accuracy.

A preferred form of the present invention is characterized in that the viscoelasticity is the viscoelasticity of the upper layer of subcutaneous tissue.
In particular, by using the viscoelasticity of the upper layer of the subcutaneous tissue as an index, the oxygen level of the subcutaneous tissue can be estimated more accurately.

Further, the present invention utilizes the correlation between the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells and the oxygen level of the subcutaneous tissue to improve the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells. An oxygen level estimating device that estimates the oxygen level using a measured value of the oxygen level as an index,
Storage means for storing correlation data indicating the correlation;
an oxygen level calculation means for calculating the oxygen level by comparing the viscoelasticity of the subcutaneous tissue of the subject's skin or the fibrosis level of the subcutaneous fat cells with the correlation data stored in the storage means; Features.

Further, the present invention utilizes the correlation between the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells and the oxygen level of the subcutaneous tissue to improve the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells. An oxygen level estimation program that estimates the oxygen level using a measured value of the oxygen level as an index,
computer,
As an oxygen level calculation means that calculates the oxygen level by comparing the viscoelasticity of the subcutaneous tissue of the subject's skin or the fibrosis level of the subcutaneous fat cells with the correlation data showing the correlation,
It is characterized by making it function.

Further, the present invention utilizes the correlation between the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells and the oxygen level of the subcutaneous tissue, and uses the oxygen level of the subcutaneous tissue as an index. The present invention also relates to a method for estimating the viscoelasticity of subcutaneous tissue or the fibrosis level of subcutaneous fat cells, which comprises estimating the viscoelasticity or fibrosis level of subcutaneous fat cells.
The present invention is two sides of the same coin as the method for estimating the oxygen level of subcutaneous tissue described above. According to the present invention, the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells can be estimated from the physiological property of the oxygen level of the subcutaneous tissue.

In a preferred embodiment of the present invention, a regression equation is used in which the evaluation value of the oxygen level of the subcutaneous tissue is used as an explanatory variable, and the measured value of the viscoelasticity of the subcutaneous tissue or the fibrosis level of subcutaneous fat cells is used as the objective variable. The method is characterized in that the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells is calculated from the evaluation value of the oxygen level.
By using the regression equation prepared in advance, the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells can be estimated more accurately.

A preferred embodiment of the present invention is characterized in that the oxygen level in the subcutaneous tissue is measured by near-infrared spectroscopy.
Thereby, it is possible to non-invasively and quantitatively obtain the measurement result of the oxygen level of the subcutaneous tissue, and it is possible to estimate the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells with higher accuracy.

A preferred form of the present invention is characterized in that the viscoelasticity is the viscoelasticity of the upper layer of subcutaneous tissue.
The present invention is particularly useful for estimating the viscoelasticity of the upper layer of subcutaneous tissue.

Further, the present invention utilizes the correlation between the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells and the oxygen level of the subcutaneous tissue, and uses the oxygen level of the subcutaneous tissue as an index. A subcutaneous tissue viscoelasticity or subcutaneous fat cell fibrosis level estimation device that estimates the viscoelasticity or subcutaneous fat cell fibrosis level,
Storage means for storing correlation data indicating the correlation;
viscoelasticity or fibrosis level calculation means for calculating the viscoelasticity or fibrosis level by comparing the oxygen level of the subject's subcutaneous tissue with the correlation data stored in the storage means. do.

Further, the present invention utilizes the correlation between the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells and the oxygen level of the subcutaneous tissue, and uses the oxygen level of the subcutaneous tissue as an index. A subcutaneous tissue viscoelasticity or subcutaneous fat cell fibrosis level estimation program that estimates the viscoelasticity or subcutaneous fat cell fibrosis level,
computer,
A viscoelasticity or fibrosis level calculation means that calculates the viscoelasticity or fibrosis level by comparing the oxygen level of the subject's subcutaneous tissue with the correlation data showing the correlation,
It is characterized by making it function.

According to the present invention, the oxygen level of the subcutaneous tissue can be estimated from the viscoelasticity of the subcutaneous tissue or the fibrosis level of subcutaneous fat cells.
Further, according to the present invention, the viscoelasticity of the subcutaneous tissue or the fibrosis level of subcutaneous fat cells can be estimated from the oxygen level of the subcutaneous tissue.

1 is a hardware block diagram illustrating an embodiment of an oxygen level estimating device of the present invention. FIG. FIG. 1 is a hardware block diagram showing an embodiment of the viscoelasticity or fibrosis level estimating device of the present invention. It is a graph showing that whole body oxygen saturation decreases with aging. It is a graph showing that oxygen saturation of local tissue decreases with aging. It is a graph showing the correlation between oxygen saturation of local tissue and viscoelasticity of subcutaneous tissue. It is a bar graph showing the expression levels of the vegf gene, col1a1 gene, col3a1 gene, tgf-β gene, and lox gene in cells cultured under normal oxygen concentration conditions and hypoxic conditions.

<1> Method for estimating oxygen level in subcutaneous tissue Hereinafter, embodiments of the present invention will be described in detail.
A positive correlation exists between the viscoelasticity of the subcutaneous tissue (hereinafter also simply referred to as viscoelasticity) and the oxygen level of the subcutaneous tissue (hereinafter also simply referred to as oxygen level). In other words, the higher the viscoelasticity, the higher the oxygen level.
On the other hand, a negative correlation exists between the fibrosis level of the fibrous structure surrounding fat cells (hereinafter also simply referred to as fibrosis level) and the oxygen level of the subcutaneous tissue. In other words, the lower the fibrosis level, the higher the oxygen level.
The present invention utilizes such a correlation to estimate the oxygen level of the subcutaneous tissue from the viscoelasticity of the subcutaneous tissue or the fibrosis level of the fibrous structure surrounding fat cells.

The subcutaneous tissue can be roughly classified into three layers in the depth direction, each having a substantially uniform viscoelasticity. Specifically, when the subcutaneous tissue is divided in the depth direction at a ratio of 1:2:1, the layer located at the top (the layer in contact with the dermis) is called the upper layer of the subcutaneous tissue.
In the present invention, it is preferable to use the viscoelasticity of the upper layer of the subcutaneous tissue, which is the layer closest to the dermis, as an index.

The above correlation is preferably expressed as a formula or model. As the equation or model, a simple regression equation or a simple regression model is preferably mentioned.

Viscoelasticity refers to a property that combines both viscosity and elasticity. Therefore, when evaluating viscoelasticity, both viscosity and elasticity are evaluated. However, it is difficult to clearly distinguish between viscosity and elasticity in living tissues, and viscoelasticity is generally evaluated mainly by elastic modulus (Young's modulus).
Further, the viscoelasticity may be evaluated by "strain" based on Hooke's law (formula 1 below).

Formula 1

Therefore, the viscoelasticity used as an index in the present invention may be calculated as an elastic modulus (Young's modulus) or a strain.
In creating the above regression equation or regression model, the explanatory variable may be the Young's modulus or strain of the subcutaneous tissue, and the target variable may be the oxygen level.

Oxygen level refers to the oxygen saturation in the blood. The oxygen saturation may be arterial oxygen saturation (SaO ₂ ) measured by directly collecting arterial blood, or percutaneous oxygen saturation (SpO ₂ ) measured using a measuring device such as a pulse oximeter. It may be. Alternatively, local tissue oxygen saturation (rSO ₂ ) using near-infrared spectroscopy (NIRS) may be used.

As used herein, the oxygen level of the subcutaneous tissue refers to the oxygen saturation level of the local tissue circulating through the capillaries of the subcutaneous tissue, especially in the peripheral region, among the arterial blood circulating throughout the body.

Subcutaneous fat cells refer to fat cells that make up most of the subcutaneous tissue. Fat cells form clusters and exist as fat lobules surrounded by connective tissues such as collagen and elastin.

A network of blood vessels and nerves runs around the fat lobules, transporting nutrients and waste products. The lobulated structure that is formed when fat lobules are surrounded by connective tissue, blood vessels, etc. in a network is called a fibrous structure that envelops fat cells. The fibrous structures surrounding adipocytes can be divided into different constituent units, such as the entire fibrous structure forming the fat lobules themselves, or partial local structures of connective tissue that exist around individual adipocytes.
The fibrosis level of subcutaneous fat cells, which is used as an index in the present invention, is particularly preferably the fibrosis level of fibrous structures existing around individual fat cells.

Here, fibrosis refers to a phenomenon in which tissue becomes hard due to an abnormal increase in collagen surrounding the tissue or crosslinking of collagen fibers.
As a factor for fibrosis, an increase in the expression level of collagen itself and an increase in the expression level of genes involved in the crosslinking reaction of the collagen fiber structure can be assumed.
As used herein, the fibrosis level refers to the degree or degree of progression of fibrosis.

Viscoelasticity of subcutaneous tissue can be measured by ultrasound elastography. Ultrasonic elastography methods include strain imaging, which deforms the skin by applying stress σ externally, measures strain ε, and determines Young's modulus E using Hooke's law, and propagates shear waves through the skin, and measures the propagation of the strain ε. Known methods such as shear wave imaging, which determines the Young's modulus E by measuring the velocity _CS , can be used without limitation.

As the ultrasonic elastography apparatus, for example, "ARIETTA E70" or "Noblus" manufactured by Hitachi, "Acuson S2000e" manufactured by Siemens Healthcare, etc. can be used.

According to ultrasonic elastography, it is possible to obtain an image of the distribution of viscoelasticity (Young's modulus (or strain depending on the model)) in the internal cross section of the skin. In practicing the present invention, the average viscoelasticity, which is non-uniformly distributed in the subcutaneous tissue, may be used as the measured value.

When measuring the viscoelasticity of subcutaneous tissue, it is preferable to divide the subcutaneous tissue into three layers in the depth direction: an upper layer, a middle layer, and a lower layer, and calculate the average viscoelasticity of each layer. In particular, it is preferable to use an average viscoelasticity of the upper layer of the subcutaneous tissue as a measurement value to estimate the oxygen level of the subcutaneous tissue.

The method for evaluating the fibrosis level is not particularly limited.
Examples of invasive methods include a method of calculating relative evaluation values using a photo scale. More specifically, a plurality of images of subcutaneous fat cells with different levels of fibrosis are prepared in advance. Using this as a reference photo, scores are given to images of subcutaneous fat cells collected from subjects.

Since invasive methods impose a burden on the subject, it is preferable to evaluate the fibrosis level of subcutaneous fat cells using a non-invasive method.
Non-invasive methods include methods using ultrasound. More specifically, a subcutaneous fat layer portion is cut out from a tomographic image of the skin obtained by ultrasound and used as an image for analysis. Regarding the acquired analysis image, the fibrosis level can be evaluated from the feature amount obtained using image processing software.
Examples of such feature quantities include parameters calculated by converting an image into a gray scale, a histogram, a binarization, or the like.

In the present invention, it is preferable to convert the image for analysis into a histogram and employ the skewness of this histogram as an evaluation value of the fibrosis level.
Since a histogram with a low skewness (indicating a substantially normal distribution) indicates a low skew, it can be seen that the fibrosis level of subcutaneous fat cells is high. On the other hand, from a histogram with a high skewness (indicating a non-normal distribution), it can be determined that the fibrosis level of subcutaneous fat cells is low.

As the image processing software, any known software such as open source "ImageJ" may be used.

The ultrasonic device used to evaluate the fibrosis level can be the same as that used for measuring the viscoelasticity of the subcutaneous tissue described above.

In this way, the fibrosis level of subcutaneous fat cells, which is used as an index in the present invention, may be used as an evaluation value of the fibrosis level measured by the method described above.
In creating the above regression equation or regression model, the explanatory variable may be the evaluation value of the fibrosis level of subcutaneous fat cells, and the target variable may be the oxygen level.

<2> Method for estimating the viscoelasticity of subcutaneous tissue or the fibrosis level of subcutaneous fat cells As described above, a positive correlation exists between the viscoelasticity of subcutaneous tissue and the oxygen level of subcutaneous tissue. Furthermore, a negative correlation exists between the fibrosis level of subcutaneous fat cells and the oxygen level of subcutaneous tissue.
The present invention utilizes such a correlation to estimate the viscoelasticity of subcutaneous tissue or the fibrosis level of subcutaneous fat cells from the oxygen level of subcutaneous tissue.
The above correlation is preferably expressed as a formula or model. As the equation or model, a simple regression equation or a simple regression model is preferably mentioned.

The method for evaluating oxygen levels is not particularly limited.
As mentioned above, invasive methods include a method of collecting arterial blood from a subject and measuring oxygen partial pressure. In addition, non-invasive methods include a method that uses a pulse oximeter to detect the blood flow in the artery at the tip of the finger and measures SpO ₂ , and a method that uses NIRS to measure rSO ₂ in the cheek area, etc. can be mentioned.

When using a pulse oximeter, the type of probe is not particularly limited, and a transmission type or reflection type may be used. Commercially available products can be used as appropriate.
Similarly, when using NIRS, commercially available products can be used as appropriate without any particular restrictions.

In addition, in the above item <1> and this item, methods for measuring or evaluating viscoelasticity, fibrosis level, and oxygen level as indicators for estimation have been explained. This explanation also applies to methods of measuring or evaluating viscoelasticity, fibrosis level, and oxygen level for creating regression equations or regression models.

<3> Apparatus for estimating oxygen level in subcutaneous tissue The apparatus for estimating oxygen level in subcutaneous tissue will be described below with reference to FIG. 1. The subcutaneous tissue oxygen level estimation device of the present invention is a device for implementing the subcutaneous tissue oxygen level estimation method described in item <1> above. Therefore, the explanation in item <1> above is also applicable to the subcutaneous tissue oxygen level estimation device described below.

The subcutaneous tissue oxygen level estimation device 1 of the present invention includes a storage means 121 for storing oxygen level correlation data indicating a correlation between the viscoelasticity of the subcutaneous tissue or the fibrosis level of subcutaneous fat cells and the oxygen level of the subcutaneous tissue. , an oxygen level calculation means 112 that calculates the oxygen level by comparing the viscoelasticity of the subcutaneous tissue of the subject's skin or the fibrosis level of the subcutaneous fat cells with the oxygen level correlation data stored in the storage means 121; Be prepared.

As shown in FIG. 1, the subcutaneous tissue oxygen level estimating device 1 includes a viscoelasticity or fibrosis level measuring unit 13, a ROM (Read Only Memory) 12 including a storage unit 121, and a CPU (CPU) including an oxygen level calculation unit 112. It has a central processing unit (Central Processing Unit) 11 and an oxygen level display section 14.

In a preferred embodiment of the present invention, a quantification means 111 for quantifying the viscoelasticity of the subcutaneous tissue of the subject's skin or the fibrosis level of subcutaneous fat cells measured or evaluated by the viscoelasticity or fibrosis level measurement unit 13 is provided. It is preferable to have one. The CPU 11 includes a numerical conversion means 111.

The oxygen level display section 14 is a display that displays the estimated value of the oxygen level of the subcutaneous tissue calculated by the oxygen level calculation means 112.

The subcutaneous tissue oxygen level estimating device 1 of the present invention having such a configuration can easily estimate the subcutaneous tissue of a subject by simply measuring or evaluating the viscoelasticity of the subcutaneous tissue of the subject's skin or the fibrosis level of subcutaneous fat cells. Tissue oxygen levels can be calculated.

In other embodiments, instead of the viscoelasticity or fibrosis level measurement section 13 and the digitization means 111, a separately measured or evaluated viscoelasticity or fibrosis level measurement value or evaluation value is input. It may also include a fibrosis level input section.

<4> Program for estimating oxygen level in subcutaneous tissue The present invention also relates to a program for estimating oxygen level in subcutaneous tissue that causes a computer to execute the method for estimating oxygen level in subcutaneous tissue described above. The program of the present invention corresponds to each means in the CPU included in the oxygen level estimating device of the present invention described above, and will be described using the reference numerals shown in FIG. 1.

The subcutaneous tissue oxygen level estimation program of the present invention calculates the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells of the subject's skin, and calculates the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells and the oxygen level of the subcutaneous tissue. The present invention is characterized in that a computer is made to function as the oxygen level calculation means 112 that calculates the oxygen level by comparing it with oxygen level correlation data showing the correlation with the oxygen level.

The oxygen level estimation program of the present invention is preferably configured so that a computer functions as the numerical means 111, as shown in the block diagram of FIG.

<5> Apparatus for estimating the viscoelasticity of subcutaneous tissue or the fibrosis level of subcutaneous fat cells The apparatus for estimating the viscoelasticity of subcutaneous tissues or the fibrosis level of subcutaneous fat cells will be described below with reference to FIG. 2. The device for estimating the viscoelasticity of subcutaneous tissue or the fibrosis level of subcutaneous fat cells of the present invention implements the method for estimating the viscoelasticity of subcutaneous tissue or the fibrosis level of subcutaneous fat cells described in item <2> above. It is a device for Therefore, the explanation in item <2> above is also applicable to the following device for estimating the viscoelasticity of subcutaneous tissue or the fibrosis level of subcutaneous fat cells.

The device 2 for estimating the viscoelasticity of subcutaneous tissue or the fibrosis level of subcutaneous fat cells of the present invention is a viscoelasticity or a A storage means 221 for storing fibrosis level correlation data and the oxygen level of the subject's subcutaneous tissue are compared with the viscoelasticity or fibrosis level correlation data stored in the storage means 221 to determine the viscoelasticity or fibrosis level. viscoelasticity or fibrosis level calculating means 212 for calculating.

As shown in FIG. 2, the device 2 for estimating the viscoelasticity of subcutaneous tissue or the fibrosis level of subcutaneous fat cells includes an oxygen level measuring section 23, a ROM 22 including a storage means 221, and a viscoelasticity or fibrosis level calculating means 212. It has a CPU 21 and a viscoelasticity or fibrosis level display section 24.

In a preferred embodiment of the present invention, it is preferable to include a digitization means 211 that digitizes the oxygen level of the subcutaneous tissue of the subject measured by the oxygen level measurement unit 23. The CPU 21 includes a numerical conversion means 211.

The viscoelasticity or fibrosis level display unit 24 is a display that displays the estimated value of the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells calculated by the viscoelasticity or fibrosis level calculating means 212.

The apparatus 2 for estimating the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells of the present invention having such a configuration can easily estimate the viscoelasticity of the subcutaneous tissue of the subject by simply measuring the oxygen level of the subcutaneous tissue of the subject. Alternatively, the fibrosis level of subcutaneous fat cells can be calculated.

Note that in other embodiments, instead of the oxygen level measuring section 23 and the digitization means 211, an oxygen level input section may be provided to input a separately measured value of the oxygen level.

<6> Program for estimating the viscoelasticity of subcutaneous tissue or the fibrosis level of subcutaneous fat cells The present invention provides a program for estimating the viscoelasticity of subcutaneous tissue or the fibrosis level of subcutaneous fat cells. The present invention also relates to a program for estimating the fibrosis level of subcutaneous fat cells. The program of the present invention corresponds to each means in the CPU included in the viscoelasticity or fibrosis level estimating device of the present invention described above, and will be described using the reference numerals shown in FIG. 2.

The program for estimating the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells of the present invention calculates the oxygen level of the subcutaneous tissue of the subject based on the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells and the oxygen level of the subcutaneous tissue. The present invention is characterized in that a computer is operated as the viscoelasticity or fibrosis level calculation means 212 that calculates the viscoelasticity or fibrosis level by comparing it with viscoelasticity or fibrosis level correlation data showing the correlation.

The viscoelasticity or fibrosis level estimation program of the present invention is preferably configured so that a computer functions as the numerical means 211, as shown in the block diagram of FIG.

<Test Example 1> Regression analysis of aging and oxygen level The oxygen saturation of the whole body arterial blood was measured for 60 subjects using a pulse oximeter (Konica Minolta). In addition, the oxygen saturation of arterial blood in the cheek area was measured for 60 subjects using NIRS (manufactured by Associate Professor Niwayama, Faculty of Engineering, Shizuoka University). Regression analysis was performed on the obtained oxygen saturation measurements (whole body: SpO2, cheek: rO2) and the age of each subject. The results are shown in Figures 3 and 4.

As shown in FIGS. 3 and 4, it was confirmed that a negative correlation was established between the subject's age, whole body oxygen saturation, and local oxygen saturation.
This result indicates that aging not only causes a deterioration of oxygen conditions throughout the body, but also deterioration of oxygen conditions in localized skin such as the cheek area.

<Test Example 2> Analysis of viscoelasticity of subcutaneous tissue and measurement of oxygen saturation of local tissue For 58 subjects, elastography images of the inside of the skin were obtained using elastography (Hitachi, Ltd.), and viscoelasticity was measured. It was measured. Regarding the measurement of viscoelasticity, the measurement area was divided into a total of four layers: the surface layer of the skin (dermis), the upper layer of subcutaneous tissue, the middle layer of subcutaneous tissue, and the lower layer of subcutaneous tissue, and the relative viscoelasticity of each layer was calculated. . The upper layer of subcutaneous tissue, the middle layer of subcutaneous tissue, and the lower layer of subcutaneous tissue were set by dividing the subcutaneous tissue at a ratio of 1:2:1 in the depth direction.

Next, the oxygen saturation of arterial blood in the cheek area of the subject was measured using NIRS (created by Associate Professor Niwayama, Faculty of Engineering, Shizuoka University). The near-infrared wavelengths used in the measurements were 770 nm and 830 nm.

<Test Example 3> Regression analysis of viscoelasticity and oxygen saturation A regression analysis was performed on the measured values of viscoelasticity and oxygen saturation obtained in Test Example 2. The results are shown in Figure 5.

As shown in FIG. 5, it was confirmed that a positive correlation existed between oxygen saturation and viscoelasticity. These results showed that the oxygen level of the subcutaneous tissue can be estimated using the viscoelasticity of the subcutaneous tissue as an index. Similarly, it was shown that the viscoelasticity of the subcutaneous tissue can be estimated using the oxygen level of the subcutaneous tissue as an index.

<Test Example 4> Cell culture under hypoxic conditions Human subcutaneous preadipocytes (HPAd) were seeded in a 24-well multiwell plate (2.0 x 10 ⁴ cells/well) with a growth medium, and then cultured until confluent. did. Thereafter, the medium was changed to a differentiation medium, and the cells were cultured for 14 days while changing the differentiation medium every 3 days to mature into subcutaneous adipocytes. Thereafter, the maintenance medium was replaced with a maintenance medium, the plate was enclosed in a hypoxic culture device (BIONIX, manufactured by Sugiyama Giken) equipped with an oxygen absorber, and the culture was continued after adjusting the oxygen concentration to 1%. At this time, as a control, cells were also prepared in which the plate was enclosed in a hypoxic culture device without an oxygen scavenger and the cells were continued to be cultured. One day after changing to the maintenance medium, the culture was terminated, and mRNA was extracted by the following procedure.

After washing the cells in the wells with PBS, QIAzol Lysis Reagent from the RNeasy Lipid Tissue Kit (QIAGEN) was added (1 mL/well) to extract mRNA from the cells.
The extracted mRNA was made into cDNA using Superscript VILO cDNA Synthesis Kit (Life Technologies).
Real-time PCR was performed using QuantiTect Primer Assay, and the expression levels of the col1a1 gene, col3a1 gene, tgf-β gene, and lox gene were measured. At this time, the expression level of the vegf gene, which is a marker for hypoxia response, was also measured. The results are shown in FIG.

As shown in FIG. 6, an increase in the expression level of the vegf gene was observed in cells cultured under hypoxic conditions. In other words, it was confirmed that the cells caused a hypoxic response reaction by culturing under hypoxic conditions.

Moreover, as shown in FIG. 6, it was found that the expression levels of the col1a1 gene and the col3a1 gene did not change when cultured under hypoxic conditions.
On the other hand, the expression levels of the tgf-β gene and lox gene were significantly increased by culturing under hypoxic conditions (FIG. 6).

LOX, a product of the lox gene, is an enzyme involved in crosslinking collagen fibers. Furthermore, TGF-β is a factor involved in the production of collagen fibers. In other words, the results shown in FIG. 6 indicate that under hypoxic conditions, the production of LOX and TGF-β associated with collagen fibers increases, and fibrosis can be promoted.

Considering that Test Examples 1 and 4 showed that the oxygen status of local tissues worsens with aging and that fibrosis of subcutaneous fat cells progresses under hypoxic conditions, it is found that subcutaneous fat cells It is thought that there is a negative correlation between the level of fibrosis in the skin and the oxygen level in the subcutaneous tissue. Therefore, it is possible to estimate the fibrosis level of subcutaneous fat cells using the oxygen level of the subcutaneous tissue as an index, and similarly, it is also possible to estimate the oxygen level of the subcutaneous tissue using the fibrosis level of subcutaneous fat cells as an index.

The present invention can be applied to skin analysis technology.

1 Oxygen level estimation device 11 CPU
111 Numericalization means 112 Oxygen level calculation means 12 ROM
121 Storage means 13 Viscoelasticity or fibrosis level measurement section 14 Oxygen level display section 2 Viscoelasticity or fibrosis level estimation device 21 CPU
211 Numerical conversion means 212 Viscoelasticity or fibrosis level calculation means 22 ROM
221 Storage means 23 Oxygen level measuring section 24 Viscoelasticity or fibrosis level display section

Claims (12)

Based on the positive correlation between the viscoelasticity of the subcutaneous tissue and the oxygen level of the subcutaneous tissue, the greater the viscoelasticity, the higher the oxygen level. Using the relationship that the lower the fibrosis level of subcutaneous fat cells is, the higher the oxygen level is based on the negative correlation between A method for estimating an oxygen level, the method comprising estimating the level. The method for estimating oxygen level according to claim 1, characterized in that the viscoelasticity of the subcutaneous tissue is measured by ultrasonic elastography . Using a regression equation in which the explanatory variable is the viscoelasticity of the subcutaneous tissue or the fibrosis level of the subcutaneous fat cells measured using elastography , and the objective variable is the evaluated value of the oxygen level of the subcutaneous tissue, 3. The method for estimating an oxygen level according to claim 1, wherein the oxygen level is calculated from a measured value of viscoelasticity or fibrosis level of subcutaneous fat cells. The method for estimating an oxygen level according to any one of claims 1 to 3, wherein the viscoelasticity is the viscoelasticity of an upper layer of subcutaneous tissue. Based on the positive correlation between the viscoelasticity of the subcutaneous tissue and the oxygen level of the subcutaneous tissue, the greater the viscoelasticity, the higher the oxygen level. Using the relationship that the lower the fibrosis level of subcutaneous fat cells is, the higher the oxygen level is, based on the negative correlation between An oxygen level estimating device that estimates the oxygen level as
Storage means for storing correlation data indicating the correlation;
an oxygen level calculation means for calculating the oxygen level by comparing the viscoelasticity of the subcutaneous tissue of the subject's skin or the fibrosis level of the subcutaneous fat cells with the correlation data stored in the storage means; Features: Oxygen level estimation device. Based on the positive correlation between the viscoelasticity of the subcutaneous tissue and the oxygen level of the subcutaneous tissue, the greater the viscoelasticity, the higher the oxygen level. Using the relationship that the lower the fibrosis level of subcutaneous fat cells is, the higher the oxygen level is, based on the negative correlation between An oxygen level estimation program for estimating the oxygen level as,
computer,
As an oxygen level calculation means that calculates the oxygen level by comparing the viscoelasticity of the subcutaneous tissue of the subject's skin or the fibrosis level of the subcutaneous fat cells with the correlation data showing the correlation,
An oxygen level estimation program that is characterized by functioning. Based on the positive correlation between the viscoelasticity of the subcutaneous tissue and the oxygen level of the subcutaneous tissue, the greater the viscoelasticity, the higher the oxygen level. Using the relationship that the lower the fibrosis level of subcutaneous fat cells is, the higher the oxygen level is, which is based on the negative correlation between A method for estimating the viscoelasticity of subcutaneous tissue or the fibrosis level of subcutaneous fat cells, the method comprising estimating the fibrosis level. Using a regression equation with the evaluation value of the oxygen level of the subcutaneous tissue as an explanatory variable and the objective variable as the viscoelasticity of the subcutaneous tissue measured using elastography or the measured value of the fibrosis level of subcutaneous fat cells, 8. The method for estimating viscoelasticity or fibrosis level according to claim 7, characterized in that the viscoelasticity of subcutaneous tissue or the fibrosis level of subcutaneous fat cells is calculated from the evaluated value of oxygen level. The method for estimating viscoelasticity or fibrosis level according to claim 7 or 8, characterized in that the oxygen level in the subcutaneous tissue is measured by near-infrared spectroscopy. The method for estimating viscoelasticity or fibrosis level according to any one of claims 7 to 9, wherein the viscoelasticity is the viscoelasticity of an upper layer of subcutaneous tissue. Based on the positive correlation between the viscoelasticity of the subcutaneous tissue and the oxygen level of the subcutaneous tissue, the greater the viscoelasticity, the higher the oxygen level. Using the relationship that the lower the fibrosis level of subcutaneous fat cells is, the higher the oxygen level is, which is based on the negative correlation between An apparatus for estimating viscoelasticity of subcutaneous tissue or fibrosis level of subcutaneous fat cells for estimating fibrosis level,
Storage means for storing correlation data indicating the correlation;
viscoelasticity or fibrosis level calculation means for calculating the viscoelasticity or fibrosis level by comparing the oxygen level of the subject's subcutaneous tissue with the correlation data stored in the storage means. A device for estimating the viscoelasticity of subcutaneous tissue or the fibrosis level of subcutaneous fat cells. Based on the positive correlation between the viscoelasticity of the subcutaneous tissue and the oxygen level of the subcutaneous tissue, the greater the viscoelasticity, the higher the oxygen level. Using the relationship that the lower the fibrosis level of subcutaneous fat cells is, the higher the oxygen level is, which is based on the negative correlation between A subcutaneous tissue viscoelasticity or subcutaneous fat cell fibrosis level estimation program for estimating the fibrosis level,
computer,
A viscoelasticity or fibrosis level calculation means that calculates the viscoelasticity or fibrosis level by comparing the oxygen level of the subject's subcutaneous tissue with the correlation data showing the correlation,
A program for estimating the viscoelasticity of subcutaneous tissue or the fibrosis level of subcutaneous fat cells.