CN110702930B

CN110702930B - Application of 24-hydroxycholesterol in preparation of related products for diagnosis and treatment of depression

Info

Publication number: CN110702930B
Application number: CN201910837982.2A
Authority: CN
Inventors: 孙作厘; 杨健; 王刚; 周晶晶; 贺毅; 丰雷
Original assignee: Beijing Anding Hospital
Current assignee: Beijing Anding Hospital
Priority date: 2019-09-05
Filing date: 2019-09-05
Publication date: 2023-08-15
Anticipated expiration: 2039-09-05
Also published as: CN110702930A

Abstract

The invention provides the use of 24-hydroxycholesterol or a reagent for detecting 24-hydroxycholesterol in the preparation of a reagent or kit for diagnosing depression, and the use of a reagent or kit for predicting and/or judging the therapeutic effect of an antidepressant. The 24-hydroxycholesterol can be used as a biomarker for diagnosing depression and predicting curative effect, has higher sensitivity and specificity for depression diagnosis, can diagnose and predict the depression by only measuring one index of the level of the 24-hydroxycholesterol in peripheral blood, and is convenient to popularize and use.

Description

Application of 24-hydroxycholesterol in preparation of related products for diagnosis and treatment of depression

Technical Field

The invention belongs to the technical field of biology, and particularly relates to application of a brain cholesterol metabolite 24-hydroxycholesterol (24 OHC) in depression diagnosis and antidepressant curative effect prediction, and application of preparing corresponding reagents.

Background

Depression (Major depressive disorder, MDD) is an affective disorder mental disease caused by a variety of factors with sustained depression of emotion as a major symptom. Epidemiological data have shown prevalence of MDD in the world as high as 5% -12%, with about 15% of the individuals who have had depressive episodes throughout their lives, with 15% of MDD patients suicidal. The World Health Organization (WHO) predicts that MDD will be the disease of the second largest economic burden in the world following cardiovascular disease in 2020. MDD has become a major public health problem that needs to be addressed urgently as a global mental system disorder with high morbidity, mortality, and disability.

At present, the main difficulties faced in diagnosis and treatment of depression are: the pathogenesis of (1) is not yet defined: the pathogenesis of depression is numerous and mainly comprises neurotrophic factor deficiency, monoamine neurotransmitter disorder, oxidative stress disorder and the like. These hypotheses provide a theoretical basis for revealing the pathophysiological mechanisms of depression, but have not gained widespread acceptance. (2) lack of objective test diagnostic methods: diagnosis of depression relies mainly on subjective identification of the patient's clinical symptoms by a physician. However, the clinical manifestations of depression are highly heterogeneous, and a small proportion of patients have hyperactivity, euphoria, hallucinations, delusions as the main clinical manifestations, which are easily confused with the symptoms of other mental diseases, such as bipolar disorder and schizophrenia, making the symptom-based clinical diagnostic methods less accurate. For example, one meta analysis found that MDD patients had a diagnostic accuracy of only 47%, while DSM-5 (fifth edition of the handbook for diagnosis and statistics of mental disorders) was tested on site to find that there was 28% consistency in diagnosis of depression. (3) antidepressants act slower: traditional antidepressants, represented by selective 5-hydroxytryptamine reuptake inhibitors (SSRIs) and norepinephrine reuptake inhibitors, typically take 2-4 weeks to begin to take effect, which results in some patients becoming unauthorised and stopped in early stages of treatment due to ineffective subjective sensory therapy, even interrupting the therapy, not only increasing the risk of suicide, but also affecting the long-term prognosis, causing tremendous economic and social burden to the patient.

In the aspect of research of diagnosis and treatment markers for depression, blood indexes are easy to obtain, the wound is small, the price is low, and automatic detection is easy, so that the method has received extensive attention.

Disclosure of Invention

The technical problem to be solved by the invention is that no blood biomarker is uniformly approved in the aspects of depression diagnosis and curative effect prediction at present, that is, a diagnosis method for objectively judging depression and a method for judging the curative effect of antidepressant drugs are lacked in the prior art.

In order to solve the technical problems, the biomarker related to depression needs to be screened, so that the potential pathophysiological mechanism of the biomarker is revealed, and objective diagnosis and curative effect prediction methods are developed. Researchers believe that peripheral blood total cholesterol has abnormal changes in patients with depression and can be used as a biomarker, but the conclusions of different researchers are not consistent, so that the peripheral blood total cholesterol is difficult to be used as an objective biomarker for diagnosis and treatment effect prediction of depression.

The inventor finds that the main metabolite of brain cholesterol is 24-hydroxycholesterol (24-OHC), and more than 90% of peripheral blood 24OHC is derived from brain, which provides a convenient condition for detecting central lesions in peripheral blood. Results of cadaver brain studies in patients with suicidal depression indicate a significant increase in 24OHC in the brains of the patients. Thus, the peripheral blood brain cholesterol metabolite 24OHC has potential as a biomarker for depression.

The inventors have further studied and found that the concentration of 24OHC in the peripheral blood plasma of patients suffering from depression is significantly increased relative to normal population. Meanwhile, for patients with depression treated by antidepressant drugs, the reactions of the patients with depression treated by the antidepressant drugs are divided into two groups which are effective in treatment and ineffective in treatment, and the plasma 24OHC level of the patients with effective treatment is found to be obviously higher than that of the patients with control group and ineffective treatment through comparison among the groups, and the 24OHC level in peripheral blood of the patients with effective treatment is gradually reduced as the treatment progresses. Therefore, the plasma 24OHC level can be used as a biomarker for diagnosis of depression patients and also can be used as a biomarker for predicting curative effect of depression patients.

Based on the research findings, the invention provides the following technical scheme:

in one aspect, the invention provides the use of 24-hydroxycholesterol or a reagent for detecting 24-hydroxycholesterol in the manufacture of a reagent or kit for diagnosing depression.

In another aspect, the invention provides the use of 24-hydroxycholesterol or a reagent for detecting 24-hydroxycholesterol in the manufacture of a reagent or kit for predicting and/or judging the therapeutic effect of an antidepressant.

Preferably, the use as described above, wherein the kit is selected from a biochemical diagnostic kit, an immunodiagnostic kit or a molecular diagnostic kit; preferably, the kit is selected from one or more of Western blot kit, enzyme-linked immunosorbent assay (ELISA) kit, radioimmunoassay (RIA) kit, radioimmunoassay kit, two-dimensional biphasic immunodiffusion kit, rocket immunoelectrophoresis kit, immunohistochemical staining kit, immunoprecipitation assay kit, complement fixation assay kit, fluorescence Activated Cell Sorting (FACS) kit, aptamer chip kit, microarray kit, and protein chip kit.

Preferably, the use as described above, wherein the kit comprises a depression rating scale; preferably, the depression rating scale is selected from one or more of hamilton depression scale (HAMD), montgomery depression scale (MADRS), zung depression self-rating scale (SDS), beck depression self-rating scale (BDI), rapid rating scale for depression symptoms (QIDS), hypomania self-rating scale (HCL-32), mood Disorder Questionnaire (MDQ), yankee mania scale (YMRS) and depression screening scale (PHQ 9); more preferably, the depression rating scale is the hamilton depression scale (HAMD).

Preferably, the above use, wherein the diagnosis of depression comprises the steps of:

step 1: determining the concentration of 24-hydroxycholesterol in the peripheral blood of the subject;

step 2: comparing the concentration of 24-hydroxycholesterol measured in step 1 with a standard concentration; and

step 3: the subject is judged to be at risk for depression, for example if the plasma 24-hydroxycholesterol concentration is higher than 40.85ng/ml, the probability of depression is about 53%.

Preferably, the above use, wherein predicting and/or judging the therapeutic effect of an antidepressant comprises the steps of:

step 1: determining the concentration of 24-hydroxycholesterol in the peripheral blood of the subject at different points in time of the treatment, and comparing the concentrations of 24-hydroxycholesterol in the peripheral blood of the subject determined at different points in time;

preferably, in step 1, the drug therapy is indicated to be ineffective if the concentration of 24-hydroxycholesterol in the peripheral blood of the subject exhibits a trend of increasing with the progress of the therapy, and the drug therapy is indicated to be effective if the concentration of 24-hydroxycholesterol in the peripheral blood of the subject exhibits a trend of decreasing with the progress of the therapy.

In another aspect, the invention provides a kit for diagnosing depression or for predicting and/or judging the therapeutic effect of an antidepressant, said kit comprising 24-hydroxycholesterol and a depression evaluation scale; preferably, the depression rating scale is selected from one or more of hamilton depression scale (HAMD), montgomery depression scale (MADRS), zung depression self-rating scale (SDS), beck depression self-rating scale (BDI), rapid rating scale for depression symptoms (QIDS), hypomania self-rating scale (HCL-32), mood Disorder Questionnaire (MDQ), yankee mania scale (YMRS) and depression screening scale (PHQ 9); more preferably, the depression rating scale is the hamilton depression scale (HAMD).

In another aspect, the invention provides a kit for diagnosing depression or for predicting and/or judging the therapeutic effect of an antidepressant, said kit comprising reagents for detecting 24-hydroxycholesterol and a depression evaluation scale; preferably, the depression rating scale is selected from one or more of hamilton depression scale (HAMD), montgomery depression scale (MADRS), zung depression self-rating scale (SDS), beck depression self-rating scale (BDI), rapid rating scale for depression symptoms (QIDS), hypomania self-rating scale (HCL-32), mood Disorder Questionnaire (MDQ), yankee mania scale (YMRS) and depression screening scale (PHQ 9); more preferably, the depression rating scale is the hamilton depression scale (HAMD).

Preferably, the above use or the above kit, wherein the reagent for detecting 24-hydroxycholesterol is selected from 24-hydroxycholesterol ligand or an antibody to 24-hydroxycholesterol ligand, an antibody to 24-hydroxycholesterol, a chromogenic reagent, a luminescent marker, a dye, a fluorescent marker, a standard, an alkaline hydrolysis reagent, a derivatizing reagent, an internal standard, and an external standard; preferably, the standard is selected from serum albumin; further preferably, the alkaline hydrolysis reagent is selected from one or more of butylhydroxytoluene, potassium hydroxide, ethylenediamine tetraacetic acid and ethanol; further preferably, the derivatizing agent is selected from one or more of N' -diisopropylcarbodiimide, nicotinamide and 4-dimethylaminopyridine; further preferably, the internal standard is selected from D5 deuterium cholesterol and/or D7 deuterium cholesterol; further preferably, the external standard is selected from D5 deuterium cholesterol and/or D7 deuterium cholesterol.

Preferably, the use as described above or the kit as described above, wherein the kit contains reagents for detecting 27-hydroxycholesterol, serum amyloid P and/or vascular cell adhesion molecules.

The beneficial effects of the invention include:

the invention uses the level of 24-hydroxycholesterol as the basis for diagnosing depression and predicting the curative effect, and provides corresponding diagnosis and prediction reagents, compared with the traditional diagnosis method for diagnosing and distinguishing depression by means of symptoms and inquiry, the invention has higher sensitivity and specificity for depression diagnosis, and can better distinguish the curative effect of antidepressant before administration, thereby selectively using antidepressant, greatly improving the curative effect and shortening the treatment period.

On the other hand, the 24-hydroxycholesterol biomarker belongs to the peripheral blood index, can be conveniently obtained, and can be diagnosed and predicted by only measuring one index of the peripheral blood 24-hydroxycholesterol level, thereby being convenient for popularization and use. Meanwhile, the method for predicting depression by using the 24-hydroxycholesterol biomarker as diagnosis and curative effect can also be combined with other detection modes to obtain more reliable results.

Drawings

In order to more clearly illustrate the technical solutions of the present invention, the drawings that are needed to be used are briefly described below, it being obvious that the drawings in the following description are only some embodiments described in the present invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1-1: plasma 24OHC concentrations prior to treatment in healthy controls and in depressed patients.

Fig. 1-2: plasma ROC curves before treatment for healthy controls and depressed patients.

Fig. 2-1: the hamilton depression scale (HAMD) score after 12 weeks of antidepressant treatment in depressed patients.

Fig. 2-2: depression patients were scored on the rapid rating scale (QIDS) for symptoms of depression after 12 weeks of anti-depression treatment.

Fig. 2-3: the patients with depression were scored on the young mania scale (YMRS) after 12 weeks of antidepressant treatment.

Fig. 2-4: depression patients were scored on the depression screening scale (PHQ 9) after 12 weeks of anti-depression treatment.

Fig. 3: plasma 24OHC concentration changes before and after treatment in each group of people.

Fig. 4: differences in plasma 24OHC concentrations after 12 weeks of treatment for patients with different efficacy.

Fig. 5: correlation of the concentration difference of 24OHC in plasma at 12 weeks with HAMD reduction rate.

Detailed Description

In order that those skilled in the art will better understand the present invention, a detailed description of embodiments of the present invention will be provided below, together with the accompanying drawings, wherein it is evident that the embodiments described are only some, but not all, of the embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In one embodiment of the invention 24-hydroxycholesterol is used as biomarker in a reagent or kit for diagnosing depression or for predicting and/or judging the therapeutic effect of antidepressants. The treatment effect of antidepressant is predicted and/or judged by detecting the 24OHC concentration in the peripheral blood of the subject by using the above-mentioned reagent or kit. Specifically, peripheral blood of a subject to be tested can be extracted, plasma is separated and the 24OHC concentration is measured, the blood drawing time can be used for diagnosing the diseased state of the subject before receiving treatment, the 24OHC concentration can also be used as an index of efficacy prediction for the subject confirmed to be a patient with depression so as to select a drug applicable to the patient, and meanwhile, the blood drawing time can also be carried out along with the treatment process or after the treatment is finished so as to monitor the treatment effect.

The term "depression" is also referred to herein as a depressive disorder, a mood disorder characterized by a significant and persistent mood drop.

The term "antidepressant" refers to a group of psychotropic drugs that are primarily used to treat psychotic disorders with mood depression as a prominent symptom. Antidepressants known in the art include monoamine oxidase inhibitors (MAOI), tricyclic antidepressants (TCA), selective 5-HT reuptake inhibitors (SSRI), and the like, and specific examples of applications include, but are not limited to, ipsilazine, phenelzine, imipramine, amitriptyline, doxepin, chlorimipramine, fluoxetine, paroxetine, sertraline, fluvoxamine, citalopram, and the like.

Herein, the term "24-hydroxycholesterol" (24 OHC) is a major metabolite of brain cholesterol, having the structural formula:

there are 2 main ways of eliminating cholesterol in the brain: one is transport out of the brain through the cerebrospinal fluid via apolipoprotein E (ApoE); another more prominent pathway is oxidative metabolism: about 6-7mg of cholesterol per day enters the blood circulation through the blood brain barrier in the form of 24-hydroxycholesterol, which is catalyzed by the enzyme cholesterol-24 hydroxylase (CYP 46), a cytochrome oxidase P450, which is unique to neurons in the brain. 24-hydroxycholesterol is substantially consistent with the distribution of cholesterol in the brain, mainly in myelin sheath.

The term "diagnosis" refers to a method of detecting and/or identifying a pathological state in a subject, identifying and/or determining whether the subject has a given disease or disorder, assessing or determining future clinical progression in the subject, either before or after symptoms appear.

The term "predicting" refers to estimating or determining the likelihood that a patient will respond favorably or unfavorably to a drug (therapeutic agent) or group of drugs or treatment regimens.

The term "determining" refers to estimating or determining the likelihood that a patient has or is responding favorably or unfavorably to a drug (therapeutic agent) or group of drugs or treatment regimens.

In a specific embodiment of the present invention, the reagent for diagnosing depression, the reagent for predicting and/or judging the therapeutic effect of antidepressant is prepared as a kit, and the kit may be a biochemical diagnosis kit, an immunological diagnosis kit, a molecular diagnosis kit, or the like, preferably is prepared as the immunological diagnosis kit.

The diagnosis kit is prepared by adopting principles or methods of immunology, microbiology, molecular biology and the like, and is used for diagnosing, detecting, epidemiologically investigating and the like of human diseases in vitro.

The diagnostic kit may be of a type well known in the art including, but not limited to, western blot kits, enzyme-linked immunosorbent assay (ELISA) kits, radioimmunoassay (RIA) kits, radioimmunodiffusion kits, ouchterlony immunodiffusion kits, rocket immunoelectrophoresis kits, immunohistochemical staining kits, immunoprecipitation assay kits, complement fixation assay kits, fluorescence Activated Cell Sorting (FACS) kits, aptamer chip kits, microarray kits, protein chip kits, and the like.

The kit comprises the reagent for detecting 24OHC, wherein the reagent refers to a molecule capable of specifically determining the concentration of 24OHC, and comprises, but is not limited to, a nucleic acid molecule, a protein, a compound and the like which can be specifically bound to 24 OHC.

In one embodiment of the present invention, a protein capable of specifically binding to 24OHC may be selected as the reagent for detecting 24OHC, and in another embodiment of the present invention, an antibody, which may be an antibody capable of specifically binding to a marker protein, including but not limited to polyclonal antibodies, monoclonal antibodies, recombinant antibodies, and antigen binding fragments thereof, is preferred as the reagent for detecting 24OHC, as long as it retains antigen binding function.

In the present invention, a labeling molecule capable of being detected may be attached to the reagent for detecting 24 OHC.

The invention will now be described in more detail with reference to specific examples, which are, however, given for illustrative purposes only and are not limiting of the invention.

The reagents and instrument sources used in the examples below are shown in Table 1 below, and the reagents or instruments or procedures not described herein are those routinely determinable by one of ordinary skill in the art:

table 1 reagents and apparatus used in the examples

Reagents/apparatus	Model/specification	Manufacturer' s
			Ammonium acetate	500g content is more than or equal to 98%	National medicine group chemical reagent
Formic acid	50ml	Fluka
			Methyl tert-butyl ether	The 1L content is more than or equal to 99.9 percent	Merck
N' -diisopropylcarbodiimide	D125407 25g content is more than or equal to 99 percent	Merck
			Nicotinamide	72340 100g content is more than or equal to 99 percent	Merck
4-dimethylaminopyridine	107700 25g content is more than or equal to 99 percent	Merck
			Methanol	34860 The content of 4L is more than or equal to 99.9 percent	Merck
High performance liquid chromatograph	Agilent G1312B	Agilent
			Mass spectrometer	AB Sciex Qtrap 6500	ABI Co., ltd

Examples

Example 1: peripheral blood collection and method for measuring concentration of 24OHC in peripheral blood

1. According to the passed ethical examination experimental scheme and diagnosis standard, 91 patients with healthy control group and depression (not taking or stopping drug for more than 6 weeks) are screened, the severity of depression of the patients is evaluated by using a hamilton depression scale (HAMD), a rapid evaluation scale for depression symptoms (QIDS), a yankee mania scale (YMRS) and a depression screening scale (PHQ 9) respectively 2 weeks before and 12 weeks after the treatment of the antidepressant citalopram, and 5 milliliters of peripheral blood is simultaneously extracted into an EDTA anticoagulation tube, 3000 revolutions/separation of heart is carried out for 10 minutes, upper plasma is separated, and the obtained product is immediately packaged and stored in an ultra-low temperature refrigerator at-80 ℃ for standby.

2. The plasma is extracted and then detected for 24OHC content by a high performance liquid chromatography-mass spectrometry method, and the specific method is as follows:

(1) A standard solution of 24OHC at a concentration of 1-2000ng/ml was prepared with a 5% bovine serum albumin solution, and a 5% bovine serum albumin solution was used as a blank sample.

(2) 50 μl of standard/blank/test plasma was added to a 1.5ml EP tube, followed by 50 μl of internal standard (D5 deuterium cholesterol+D7 deuterium cholesterol 50 ng/ml) followed by 200 μl of acidic buffer (50 mM ammonium acetate, 1% formic acid) and 1ml of methyl tert-butyl ether.

(3) After thoroughly mixing, the sample was placed in a-80 ℃ refrigerator, and after cooling the aqueous phase therein to crystallize, 0.5ml of methyl tert-butyl ether phase (supernatant) was transferred to a 1.5ml centrifuge tube.

(4) The methyl tert-butyl ether was blow-dried with nitrogen at 35 ℃.

(5) Mu.l of derivatizing reagent (63 mg of N, N' -diisopropylcarbodiimide, 62mg of nicotinamide and 61mg of 4-dimethylaminopyridine in 5ml of chloroform) was added to each EP tube and mixed with heating at 35℃for 2 hours.

(6) The methylene chloride was dried with nitrogen at 35 ℃.

(7) 100 μl methanol was reconstituted and then assayed by sample injection.

In the following examples, the method described in this example was used to collect peripheral blood and measure the concentration of 24OHC in the peripheral blood.

Example 2: peripheral blood 24OHC as biomarker for depression diagnosis

1. The study included 91 patients with age and sex matched depression and healthy controls, and the basic demographics and patient symptom assessments for each group are shown in Table 2.

Table 2: subject basic population and patient clinical symptom assessment

Note that: HAMD: hamilton depression scale; QIDS: rapid rating scale for depressive symptoms; YMRS: the yankee mania scale; PHQ9: depression screening scale; NA: missing values.

Through plasma cholesterol detection, a significant increase in plasma 24OHC was found in patients with depression compared to healthy controls (fig. 1-1, p < 0.0001), suggesting that cholesterol metabolism in the brain of the patient was significantly elevated, potentially becoming a potential biomarker for depression diagnosis. In combination with subject Body Mass Index (BMI) and family history index, 24OHC concentration was used as a diagnostic index for the receiver operating characteristics curve (Receiver Operating Characteristic, ROC) curve (FIGS. 1-2) with an area under the curve of 0.784 and diagnostic sensitivity and specificity of 81.3% and 62.6%, respectively.

Example 3: peripheral blood 24OHC as biomarker for efficacy prediction of antidepressants

The treatment of the group of depressed patients was given the antidepressant citalopram and the evaluation of the scale of depression symptoms was performed 2 weeks, 4 weeks, 8 weeks and 12 weeks after the treatment (fig. 2-1 to fig. 2-4). The scores of patients are obviously reduced after 12 weeks of antidepressant treatment, and symptoms are improved. However, some patients had no obvious symptom improvement, and the patients were classified into a treatment-effective (Responders) group and a treatment-ineffective (Non-Responders) group according to the effect of treatment (a reduction rate of 50% on the hamilton depression scale) after 12 weeks. Wherein 65 patients with effective treatment and 26 patients with ineffective treatment are treated. As can be seen from fig. 2-1 to fig. 2-4, the treatment-ineffective group did not meet the criteria for clinical relief, although antidepressants had some effect.

Before treatment, plasma 24OHC concentrations were significantly higher in depressed patients than in healthy control groups, plasma 24OHC concentrations decreased over time in the active group after treatment, and plasma 24OHC concentrations increased slightly over time in the inactive group after treatment (fig. 3). After 12 weeks of treatment, there was a clear difference in 24OHC levels between groups of patients with different effects (pre-treatment-post treatment) (fig. 4, p < 0.05), further suggesting that plasma 24OHC could be a biomarker for efficacy prediction in depressed patients.

The above results suggest that there is a significant difference in the number of patients with different therapeutic effects on hydroxycholesterol, after which the relationship between hydroxycholesterol levels and symptomatic levels was further observed. For this, the fraction of HAMD scores after 12 weeks of treatment was calculated ((pre-treatment-post treatment)/pre-treatment 100) and analyzed for correlation with plasma 24OHC concentrations at 12 weeks of difference (pre-treatment-post treatment) (fig. 5): the larger difference between the front and back shows that the more the concentration of 24OHC decreases, the higher the percent reduction proves that the better the curative effect is. The results show that there is a clear positive correlation between the therapeutic change value of 24OHC and HAMD decrease rate, further suggesting a close relationship between 24OHC and therapeutic effect.

As can be seen from the above examples 2 and 3, the present invention realizes an objective diagnosis method for depression by selecting peripheral blood 24OHC as a biomarker for diagnosing the condition of a depression patient, and has higher sensitivity and specificity for depression diagnosis. Meanwhile, on the other hand, through analysis of the concentration change of the peripheral blood 24OHC before and after administration of the antidepressant, the peripheral blood 24OHC of the patient with depression can also be used as an index for predicting the curative effect of the antidepressant before administration or judging the curative effect of the antidepressant after administration.

Claims

Use of 24-hydroxycholesterol or a reagent for detecting 24-hydroxycholesterol in the preparation of a reagent or kit for determining the therapeutic effect of citalopram in the treatment of depression using the hamilton depression scale (HAMD).
2. The use according to claim 1, wherein the kit is selected from a biochemical diagnostic kit or an immunodiagnostic kit.
3. The use according to claim 1 or 2, wherein the kit is selected from one or more of a Western blot kit, an enzyme-linked immunosorbent assay (ELISA) kit, a Radioimmunoassay (RIA) kit, a radioimmunodiffusion kit, a two-dimensional biphasic immunodiffusion kit, a rocket immunoelectrophoresis kit and an immunoprecipitation assay kit.
4. The use according to claim 1 or 2, wherein judging the therapeutic effect of citalopram in the treatment of depression comprises the steps of:

step 1: the concentration of 24-hydroxycholesterol in the peripheral blood of the subject is determined at different time points of the treatment, and the concentrations of 24-hydroxycholesterol in the peripheral blood of the subject determined at different time points are compared.
5. The use of claim 4, wherein in step 1, the drug treatment is indicated to be ineffective if the concentration of 24-hydroxycholesterol in the peripheral blood of the subject exhibits a trend of increasing with treatment, and the drug treatment is indicated to be effective if the concentration of 24-hydroxycholesterol in the peripheral blood of the subject exhibits a trend of decreasing with treatment.
6. The use according to claim 1 or 2, wherein the reagent for detecting 24-hydroxycholesterol is selected from 24-hydroxycholesterol ligand or one or more of antibodies to 24-hydroxycholesterol ligand, chromogenic reagents, luminescent markers, dyes, standards, derivatizing reagents and internal standards.
7. The use according to claim 6, wherein the luminescent marker is a fluorescent marker.
8. The use of claim 6, wherein the standard is formulated from serum albumin.
9. The use according to claim 6, wherein the derivatizing agent is selected from one or more of N' -diisopropylcarbodiimide, nicotinamide and 4-dimethylaminopyridine.
10. The use of claim 6, wherein the internal standard is D5 deuterium cholesterol and D7 deuterium cholesterol.