Biomarker for predicting COPD cognitive impairment and application thereof

Abstract

The invention relates to the technical field of biological medicine, and discloses a biomarker for predicting COPD cognitive impairment and application of the biomarker. The invention finds and verifies that the specificity of stearic acid (SA) in serum and a key enzyme ELOVL6 synthesized by the stearic acid (SA) in serum in a patient with secondary cognitive impairment (CI) of chronic obstructive pulmonary disease (COPD) is improved for the first time, the level of the stearic acid (SA) and the key enzyme ELOVL6 is negatively correlated with the cognitive impairment degree, and the stearic acid (SA) and the key enzyme ELOVL6 have good prediction efficiency (AUCgt, 0.82) on the COPD-CI. On the basis, the invention provides the application of the serum SA and / or ELOVL6 as the biomarker for predicting the COPD secondary CI risk, the in-vitro diagnostic kit comprising the detection reagent of the biomarker, and the method for predicting the risk by detecting the level of the marker. The invention provides a brand-new and reliable metabolic marker tool for early warning and intervention of CI of COPD patients, and has important clinical value and transformation prospect.

Description

Technical Field

[0001] This invention relates to the field of biomedical technology, specifically to biomarkers for predicting cognitive impairment in COPD and their applications. Background Technology

[0002] Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease characterized by persistent airflow limitation. It has a high global prevalence and a heavy disease burden. Both clinical observations and epidemiological studies have found that the incidence of cognitive impairment (CI) is significantly higher in COPD patients than in healthy individuals of the same age. Approximately 20%-40% of COPD patients have varying degrees of cognitive impairment, manifested as memory loss, executive function impairment, and poor concentration, which seriously affects patients' quality of life, treatment adherence, and long-term prognosis.

[0003] Currently, the pathogenesis of secondary colic due to COPD is not fully understood. Existing research mainly focuses on traditional pathways such as systemic inflammation, oxidative stress, and hypoxemia, but lacks stable biological markers that can provide early warning. Clinically, doctors mainly rely on neuropsychological scales (such as the Montreal Cognitive Assessment, MoCA) for diagnosis, but these scales have limitations such as high subjectivity and difficulty in detecting subtle changes in the early stages of the disease, often leading to delayed intervention.

[0004] Metabolomics can systematically reflect the overall changes in endogenous small molecule metabolites in the body. Compared with traditional single inflammatory factors, the metabolite profile is more stable and better reflects long-term pathophysiological states, thus showing unique advantages in early disease prediction and classification. In recent years, fatty acid metabolism disorders have been found to play an important role in various neurodegenerative diseases (such as Alzheimer's disease), but its role in COPD-related cirrhosis (CI) has been rarely reported. Stearic acid (SA) is a common saturated long-chain fatty acid, and its in vivo levels are regulated by the synthase ELOVL6 (ultra-long chain fatty acid elongation enzyme 6). ELOVL6 catalyzes the conversion of palmitic acid (C16:0) to stearic acid (C18:0) and is a key rate-limiting enzyme in fatty acid elongation metabolism.

[0005] To date, no studies have linked serum stearic acid and ELOVL6 levels with the risk of secondary CI in COPD patients, and no related patents or products have been launched as predictive biomarkers. Therefore, the discovery of a biomarker that can accurately and early predict the risk of CI in COPD patients has urgent clinical need and significant scientific value. Summary of the Invention

[0006] To address the problems mentioned in the background section, the present invention is implemented through the following technical solution:

[0007] Biomarkers for predicting cognitive impairment in COPD, wherein the biomarkers are used in the preparation of products for predicting or assisting in the diagnosis of the risk of secondary cognitive impairment in COPD patients, wherein the biomarkers are expression products of stearic acid or ultra-long chain fatty acid elongase 6 protein or ultra-long chain fatty acid elongase 6 protein encoding genes.

[0008] Furthermore, the product is an in vitro diagnostic reagent or kit.

[0009] An in vitro diagnostic kit for predicting or assessing the risk of secondary cognitive impairment in COPD patients, comprising a reagent for detecting stearic acid levels in a serum sample of a test subject or a reagent for detecting ELOVL6 protein or its mRNA levels in a serum sample of a test subject.

[0010] Furthermore, reagents for detecting stearic acid levels include reagents and standards for liquid chromatography-mass spectrometry (LC-MS) or gas chromatography-mass spectrometry (GC-MS).

[0011] Furthermore, the reagents for detecting ELOVL6 protein levels are ELISA assay reagents, or the reagents for detecting ELOVL6 mRNA levels are reverse transcription-polymerase chain reaction reagents.

[0012] Furthermore, it also includes the reagents for detecting stearic acid levels and the reagents for detecting ELOVL6 protein or its mRNA levels.

[0013] A method for predicting the risk of secondary cognitive impairment in COPD patients includes the following steps:

[0014] (a) Obtain serum samples from the COPD patients to be tested;

[0015] (b) Detect the expression levels of stearic acid and / or ELOVL6 in the serum samples;

[0016] (c) Compare the detected expression levels with a preset threshold;

[0017] (d) Based on the comparison results, determine the risk level of secondary CI in the COPD patient. Among them, the expression levels of stearic acid and / or ELOVL6 are higher than the preset threshold, which indicates an increased risk of secondary CI.

[0018] Furthermore, the preset threshold is determined based on statistical analysis of the expression levels of stearic acid and / or ELOVL6 in the serum of healthy controls or COPD patients who have not developed CI.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] This study, which investigates biomarkers for predicting cognitive impairment in COPD and their applications, establishes serum SA and ELOVL6 as stable biomarkers for predicting COPD-CI for the first time. This overcomes the shortcomings of traditional biomarkers and provides reliable blood testing evidence for early identification of high-risk populations. It elucidates a novel mechanism by which stearic acid may participate in the pathogenesis of CI through the "metabolic-immune-neural" axis, providing a new perspective for understanding COPD-CI. The detection technologies used (LC-MS / MS, ELISA, etc.) are mature, standardized, and easily developed into diagnostic kits, suitable for large-scale screening, patient stratification, and efficacy monitoring, possessing extremely high potential for clinical translation and commercial development. Attached Figure Description

[0021] Figure 1 The diagram shows the non-targeted metabolomics analysis process and differential metabolite screening of the present invention; (A) Schematic diagram of PCA score map generation process; (B) Schematic diagram of differential metabolite screening and heatmap generation method;

[0022] Figure 2 This is a flowchart of the serum stearic acid and palmitic acid targeted absolute quantitative detection (LC-MS / MS) method of the present invention;

[0023] Figure 3 This is a schematic diagram of the animal experimental protocol and results used in this invention to evaluate the effects of exogenous stearic acid on the cognitive and behavioral functions of mice; (A) Morris water maze test; (B) open field test; (C) new object recognition test;

[0024] Figure 4 The diagram illustrates the effects of stearic acid on immune cytokines and the correlation analysis of this invention; (A) Flowchart of in vitro cell stimulation and factor detection; (B) Flowchart of clinical sample correlation analysis.

[0025] Figure 5 This is a schematic diagram illustrating the large-scale clinical cohort validation of serum SA / ELOVL6 levels and their diagnostic predictive efficacy according to the present invention; (A) Comparison of serum SA levels; (B) Comparison of serum ELOVL6 levels; (C) ROC curve of serum SA; (D) ROC curve of serum ELOVL6.

[0026] Figure 6 The scatter plot shows the correlation between serum SA / ELOVL6 levels and MoCA cognitive scores in this invention; (A) serum SA and MoCA scores; (B) serum ELOVL6 and MoCA scores. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Examples of biomarkers for predicting cognitive impairment in COPD and their applications are as follows:

[0029] Please see Figures 1-6 This refers to biomarkers for predicting cognitive impairment in COPD, which are used in the preparation of products for predicting or assisting in the diagnosis of secondary cognitive impairment in COPD patients. The biomarkers are expression products of stearic acid or ultra-long chain fatty acid elongase 6 protein or genes encoding ultra-long chain fatty acid elongase 6 protein. The products are in vitro diagnostic reagents or kits.

[0030] An in vitro diagnostic kit for predicting or assessing the risk of secondary cognitive impairment in COPD patients, comprising a reagent for detecting stearic acid levels in a serum sample of a test subject or a reagent for detecting ELOVL6 protein or its mRNA levels in a serum sample of a test subject.

[0031] In one embodiment, the reagents for detecting stearic acid levels include reagents and standards for liquid chromatography-mass spectrometry (LC-MS) or gas chromatography-mass spectrometry (GC-MS).

[0032] In one embodiment, the reagent for detecting ELOVL6 protein levels is an ELISA assay reagent, or the reagent for detecting ELOVL6 mRNA levels is a reverse transcription-polymerase chain reaction reagent.

[0033] In one embodiment, the reagent for detecting stearic acid levels and the reagent for detecting ELOVL6 protein or its mRNA levels are both included.

[0034] A method for predicting the risk of secondary cognitive impairment (CI) in COPD patients includes the following steps: (a) obtaining a serum sample from the COPD patient to be tested; (b) detecting the expression levels of stearic acid and / or ELOVL6 in the serum sample; (c) comparing the detected expression levels with a preset threshold; and (d) determining the risk level of secondary CI in the COPD patient based on the comparison results, wherein an expression level of stearic acid and / or ELOVL6 higher than the preset threshold indicates an increased risk of secondary CI. The preset threshold is determined based on statistical analysis of the expression levels of stearic acid and / or ELOVL6 in the serum of healthy controls or COPD patients who have not developed CI.

[0035] Addressing the shortcomings of existing technologies, this invention, for the first time, through systematic metabolomics screening, targeted validation, animal model and clinical cohort analysis, reveals that serum stearic acid (SA) and its key synthetic enzyme ELOVL6 are specifically elevated in patients with COPD-induced cognitive impairment (CI), and are significantly negatively correlated with the degree of cognitive impairment, thus clarifying their value as predictive biomarkers.

[0036] One objective of this invention is to provide the application of serum stearic acid (SA) as a biomarker in predicting or assisting in the diagnosis of secondary coronary syndrome (CI) in COPD. A second objective is to provide the application of serum ELOVL6 protein or the expression product of its encoding gene as a biomarker in predicting or assisting in the diagnosis of secondary CI in COPD. A third objective is to provide an in vitro diagnostic kit containing the above-mentioned biomarker detection reagents. A fourth objective is to provide a method for predicting the risk of secondary CI in COPD patients using the above-mentioned biomarkers.

[0037] First, serum metabolomics profiles were compared between COPD patients with clinical infarction (COPD-CI) and those without CI (COPD-Ctrl) using non-targeted metabolomics techniques. Stearic acid was found to be significantly upregulated in the serum of COPD-CI patients. This finding was subsequently validated using targeted mass spectrometry absolute quantification (LC-MS / MS), which also revealed a downregulation of its precursor, palmitic acid. Animal experiments confirmed that long-term exogenous stearic acid supplementation induced spatial memory and recognition memory impairment, as well as anxiety-like behaviors in mice, mimicking the cognitive and behavioral deficits of COPD-CI.

[0038] Further mechanistic investigation revealed that stearic acid can stimulate peripheral blood leukocytes to release inflammatory factors such as IL-5, IL-8, IL-10, and IL-17A, and serum stearic acid levels were positively correlated with the concentrations of these factors in the clinical cohort. Given that stearic acid synthesis is regulated by ELOVL6, this invention simultaneously detected serum SA and ELOVL6 protein levels in a large clinical cohort (n=158). Results showed that serum SA and ELOVL6 levels were significantly higher in the COPD-CI group than in the COPD-Ctrl group. Receiver operating characteristic (ROC) curve analysis showed that serum SA and ELOVL6 had excellent predictive power for COPD-CI (AUCs were 0.8371 and 0.8219, respectively). Correlation analysis further confirmed that serum SA and ELOVL6 levels were significantly negatively correlated with patients' MoCA scores.

[0039] Example 1: Non-targeted metabolomics revealed significantly elevated serum stearic acid levels in COPD-CI patients.

[0040] To identify metabolites associated with the development of secondary cognitive impairment (CI) in COPD, fasting serum samples were collected from 10 pairs of COPD patients without CI (COPD-Ctrl) and with CI (COPD-CI) for non-targeted metabolomics analysis. After protein precipitation with acetonitrile, samples were centrifuged at 12,000 rpm for 10 minutes, and the supernatant was used for LC-MS analysis. An Agilent 1290 Infinity II HPLC system coupled with a 6545 Q-TOF mass spectrometer was used. Chromatographic separation was performed using a ZORBAX Eclipse Plus C18 column (2.1 × 100 mm, 1.8 μm), with mobile phase A being water (containing 0.1% formic acid) and mobile phase B being acetonitrile (containing 0.1% formic acid), using gradient elution. Mass spectrometry was performed in positive and negative ion modes (m / z 50–1000) with collision energies of 20–40 eV. The raw data were extracted, aligned, and normalized using ProgenesisQI software, and then imported into SIMCA-P 14.1 for multivariate statistical analysis.

[0041] Principal component analysis (PCA) was used to observe the separation trend between groups, and orthogonal partial least squares discriminant analysis (OPLS-DA) was used to screen for differentially expressed metabolites. The screening criteria were: variable importance projection (VIP) > 1.0, fold change (FC) > 2 or < 0.5, and Student's t-test p < 0.05. The PCA score plots showed a clear separation between the COPD-Ctrl and COPD-CI groups, indicating an overall difference in their serum metabolic profiles (e.g., Figure 1 (As shown in A). Further investigation into differentially regulated metabolites between the COPD-Ctrl and COPD-CI groups revealed that 14 metabolites were significantly upregulated in the serum of COPD-CI patients, while 6 metabolites were significantly downregulated in the serum of COPD-CI patients (e.g., ...). Figure 1 (As shown in B). Differential metabolite analysis results showed that stearic acid was most significantly upregulated in the serum of COPD-CI patients compared to the COPD-Ctrl group (FC=10.56). Notably, palmitic acid, the main metabolite for stearic acid production, was significantly downregulated in the serum of COPD-CI patients (FC=0.27) (as shown in B). Figure 1 (As shown in B). Therefore, it is speculated that during the secondary CI in COPD, there may be a biological process of palmitic acid to stearic acid, which leads to an increase in stearic acid levels.

[0042] like Figure 1A. Schematic diagram of the principal component analysis (PCA) score plot generation method. The diagram shows that after protein precipitation and LC-MS detection, the raw data of serum samples underwent preprocessing such as peak extraction, alignment, and normalization before being imported into SIMCA-P software for PCA analysis to observe the overall metabolomic profile separation trend between the COPD-Ctrl and COPD-CI groups. B. Schematic diagram of the differential metabolite heatmap. The diagram shows the variable importance projection (VIP) values, fold change (FC), and t-test p-values ​​calculated based on the OPLS-DA model. Using VIP > 1.0, FC > 2 or < 0.5, and p < 0.05 as screening criteria, the upregulated and downregulated metabolites between groups are visually displayed.

[0043] Example 2: Absolute Quantitative Verification of Serum Stearic Acid Levels by Targeted Mass Spectrometry

[0044] To accurately validate the above findings, absolute quantification of stearic acid and palmitic acid in serum was performed using LC-MS / MS. Serum samples (50 μL) were treated with an internal standard (d3-stearic acid) followed by lipid extraction using a chloroform:methanol (2:1, v / v) mixture. After drying under nitrogen, the samples were reconstituted in methanol and analyzed using a Waters ACQUITY UPLC system and a Xevo TQ-S mass spectrometer. The chromatographic column was an ACQUITY UPLC BEH C18 (2.1 × 100 mm, 1.7 μm), and quantification was performed in multiple reaction monitoring (MRM) mode. Concentrations were calculated using a standard curve. Targeted quantification results confirmed that the serum stearic acid concentration in COPD-CI patients was significantly higher than that in the COPD-Ctrl group (p = 0.0068), while the palmitic acid concentration was significantly lower (p = 0.0002), highly consistent with non-targeted results (e.g., ...). Figure 2 (As shown).

[0045] Example 3: Exogenous stearic acid induces cognitive dysfunction in mice

[0046] Experimental Procedure: Eight-week-old C57BL / 6J wild-type mice were randomly divided into two groups: the Vehicle group (intraperitoneal injection of 5% BSA solution) and the SA group (intraperitoneal injection of stearic acid dissolved in 5% BSA, 20 mg / kg). Intervention was administered twice weekly for 12 weeks. A series of behavioral tests were conducted after the intervention.

[0047] ① Morris Water Maze: Tests spatial learning and memory. Training period is 5 days, 4 times per day, with escape latency recorded. On day 6, a detection test is conducted, recording the percentage of time the mouse spends in the target quadrant (e.g., ...). Figure 3 (As shown in A).

[0048] ② Open field test: This test assesses spontaneous activity and anxiety levels. Mice are placed in the center of a 50 cm × 50 cm open field, and the total distance traveled and the time spent in the central area are recorded over 10 minutes (e.g., ...). Figure 3 As shown in B).

[0049] ③ New Object Recognition Experiment: Testing Recognition Memory. On Day 1, mice were allowed to become familiar with two identical objects for 10 minutes. 24 hours later, one of the old objects was replaced with a new object. The time taken for the mice to explore the new and old objects within 5 minutes was recorded, and the recognition index (new object exploration time / total exploration time) was calculated (e.g., ...). Figure 3 (as shown in C).

[0050] Compared to the Vehicle group, the SA group mice exhibited slower learning speeds during the water maze training period and significantly reduced time spent in the target quadrant during the detection test (e.g., Figure 3 (As shown in A); In the open field experiment, there was no difference in total movement distance, but the time spent in the central area was significantly shortened, suggesting an increase in anxiety-like behaviors (e.g., Figure 3 As shown in B); in the new object recognition experiment, the recognition index decreased significantly, indicating impaired recognition memory (e.g., Figure 3 (As shown in C). The above results demonstrate that long-term exogenous stearic acid supplementation is sufficient to induce COPD-CI-like cognitive and behavioral deficits in mice.

[0051] like Figure 3 A. Morris water maze experiment results. The diagram shows the experimental setup, the 5-day training period (4 times per day, recording the escape latency), and the exploration test on day 6 (recording the time spent in the target quadrant). B. Open field experiment schematic diagram and results. The diagram shows the experimental setup (50 cm × 50 cm open field), the initial state of the mice placed in the central area, and the parameters for recording the total movement distance and time spent in the central area over 10 minutes. C. New object recognition experiment results. The experiment is divided into two phases: the familiarization period on day 1 (exposure to two identical objects) and the testing period 24 hours later (replacing one object with a new object). The exploration time of the mice for the old and new objects was recorded, and the recognition index was calculated.

[0052] Example 4: Stearic acid stimulates the release of inflammatory factors from immune cells and its clinical relevance

[0053] Systemic inflammatory responses and their associated inflammatory factors (such as IL-5, IL-8, IL-10, and IL-17A) are closely related to the occurrence, development, and secondary cognitive impairment (CI) of chronic obstructive pulmonary disease (COPD). To investigate whether stearic acid (SA) participates in the pathogenesis of COPD-CI by influencing the peripheral immune system and altering the inflammatory factor profile, the effect of SA on the expression of CI-related inflammatory factors was examined, and its correlation was further validated in a clinical cohort.

[0054] First, human peripheral blood leukocytes were isolated and resuspended in RPMI-1640 complete medium. The experiment was divided into a control group (DMSO treatment) and an SA stimulation group (100 μM stearic acid). After incubation at 37°C and 5% CO2 for 24 hours, the supernatant was collected. The concentrations of IL-5, IL-8, IL-10, and IL-17A in the supernatant were quantitatively detected using multiplex liquid-phase microarray technology (e.g., Luminex) or ELISA kits. Results showed that SA stimulation significantly induced the release of IL-5, IL-8, IL-10, and IL-17A from mouse peripheral blood leukocytes (p < 0.05 compared to the control group). Figure 4 (As shown in A). Further analysis of the correlation between stearic acid and related inflammatory factors was conducted in a clinical cohort. Analysis of serum samples from COPD-CI patients showed that serum stearic acid levels were statistically significantly positively correlated with the concentrations of four inflammatory factors: IL-5, IL-8, IL-10, and IL-17A (p values ​​all less than 0.05). Figure 4 (As shown in B). This result suggests that during the development of COPD-CI, elevated stearic acid may promote the release of specific inflammatory factors by activating the peripheral immune system. These inflammatory factors may indirectly negatively affect central nervous system function through mechanisms such as influencing blood-brain barrier permeability or neuroinflammatory responses, thereby participating in the development of cognitive impairment.

[0055] like Figure 4 A. Flowchart of in vitro cell stimulation and factor detection. This diagram illustrates the steps involved in isolating leukocytes from mouse peripheral blood, stimulating them for 24 hours with a medium containing DMSO (control) or 100 μM stearic acid, collecting the cell culture supernatant, and quantitatively detecting inflammatory factors such as IL-5, IL-8, IL-10, and IL-17A using multiplex liquid chromatography-array technology or ELISA. B. Schematic diagram of the correlation analysis method between inflammatory factors and stearic acid in clinical samples. This diagram illustrates the process of simultaneously detecting stearic acid concentration (LC-MS / MS) and specific inflammatory factor concentrations (such as Luminex or ELISA) in serum samples from COPD patients, and using Spearman correlation analysis to assess the association between the two.

[0056] Example 5: Clinical cohort validation of SA / ELOVL6 levels and their diagnostic efficacy

[0057] Palmitic acid (C16:0) is converted to stearic acid (C18:0) in the endoplasmic reticulum via a fatty acid elongation reaction, a process dominated by ELOVL6 (ultra-long chain fatty acid elongase 6). ELOVL6 catalyzes the condensation of palmitoyl-CoA with malonyl-CoA to form β-ketoacyl-CoA, followed by a three-step reaction of reduction, dehydration, and a second reduction (completed by coenzymes such as KAR, HCD, and TER), ultimately adding two carbon atoms to form stearic acid. ELOVL6 is the key rate-limiting enzyme in this step. Therefore, the levels of SA and ELOVL6 in the serum of COPD-Ctrl and COPD-CI patients were measured. Validation was conducted in a clinical cohort of 158 COPD patients (COPD-Ctrl: 81, COPD-CI: 77). Fasting serum was collected from all patients. SA was quantified using the LC-MS / MS method described above, and ELOVL6 protein concentration was detected using a double-antibody sandwich ELISA kit (e.g., Lifescience #ELI-26589h). ROC curve analysis demonstrates the diagnostic efficacy of serum stearic acid / ELOVL6 levels in predicting the occurrence of COPD-CI.

[0058] Compared with the COPD-Ctrl group, the serum SA and ELOVL6 levels in the COPD-CI group were significantly elevated (p < 0.0001 for both). Figure 5 (As shown in A, 5B). Further evaluation of the predictive efficacy of SA and ELOVL6 for COPD-CI using receiver operating characteristic (ROC) curves revealed that the areas under the curve (AUC) for serum SA and ELOVL6 were 0.8371 and 0.8219, respectively, indicating that both are high-performance diagnostic biomarkers with excellent diagnostic efficacy (e.g., ...). Figure 5 (as shown in C, 5D).

[0059] like Figure 5 As shown, A. In a cohort of 158 COPD patients, serum stearic acid concentration was detected using LC-MS / MS, and the level difference between the COPD-Ctrl and COPD-CI groups was compared. B. Serum ELOVL6 protein levels in the same cohort of patients were detected using ELISA, and the differences between groups were compared. C. ROC curve analysis shows the predictive power of serum stearic acid (SA) for COPD-CI (AUC = 0.8371). D. ROC curve analysis shows the predictive power of serum ELOVL6 for COPD-CI (AUC = 0.8219).

[0060] Example 6: Correlation between serum SA / ELOVL6 levels and cognitive function scores

[0061] To further explore the quantitative relationship between serum biomarkers and the degree of cognitive impairment, a systematic Spearman correlation analysis was performed on serum stearic acid (SA) levels, serum ELOVL6 protein levels, and their corresponding Montreal Cognitive Assessment (MoCA) scores in all COPD patients in this clinical cohort. The results showed that serum stearic acid (SA) levels (r = -0.2723, p = 0.0005) and serum ELOVL6 levels (r = -0.3185, p < 0.001) were both statistically significantly negatively correlated with MoCA scores (e.g., ...). Figure 6 (As shown in A, 6B). This result indicates that in the COPD patient population, higher serum SA or ELOVL6 levels are associated with lower MoCA cognitive function scores, suggesting potentially more severe cognitive impairment. This finding provides direct and strong clinical relevance evidence for using serum SA and ELOVL6 as biomarkers to predict the risk of secondary cognitive impairment in COPD patients.

[0062] like Figure 6 As shown, A. Scatter plot showing the correlation between serum stearic acid (SA) levels and MoCA scores. B. Scatter plot showing the correlation between serum ELOVL6 levels and MoCA scores.

[0063] Example 7: Composition and Application of the Reagent Kit

[0064] A diagnostic kit for predicting the risk of secondary CI in COPD, comprising:

[0065] Extraction solvent, internal standard, mobile phase, and standard curve for LC-MS / MS detection of serum stearic acid.

[0066] Coating antibody, detection antibody, enzyme-labeled secondary antibody, substrate and standard for ELISA detection of serum ELOVL6 protein.

[0067] When applying this method, serum samples are collected from COPD patients, and the concentrations of SA and ELOVL6 are measured separately. The results are compared with the cutoff values ​​determined from data of healthy or low-risk populations. If the results are higher than the cutoff values, it indicates that the patient has a higher risk of secondary CI.

[0068] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A biomarker for predicting cognitive impairment in COPD, said biomarker being used in the preparation of products for predicting or assisting in the diagnosis of the risk of secondary cognitive impairment in COPD patients, characterized in that, The biomarker is the expression product of the gene encoding stearic acid or ultra-long chain fatty acid elongase 6 protein or ultra-long chain fatty acid elongase 6 protein.

2. The biomarker for predicting cognitive impairment in COPD according to claim 1, characterized in that, The product is an in vitro diagnostic reagent or kit.

3. An in vitro diagnostic kit for predicting or assessing the risk of secondary cognitive impairment in COPD patients, employing the biomarker for predicting COPD cognitive impairment as described in claim 2, characterized in that, It contains reagents for detecting stearic acid levels in a serum sample of a test subject or reagents for detecting ELOVL6 protein or its mRNA levels in a serum sample of a test subject.

4. The in vitro diagnostic kit for predicting or assessing the risk of secondary cognitive impairment in COPD patients according to claim 3, characterized in that, Reagents for detecting stearic acid levels include reagents and standards for liquid chromatography-mass spectrometry (LC-MS) or gas chromatography-mass spectrometry (GC-MS).

5. The in vitro diagnostic kit for predicting or assessing the risk of secondary cognitive impairment in COPD patients according to claim 3, characterized in that, The reagents for detecting ELOVL6 protein levels are ELISA assay reagents, or the reagents for detecting ELOVL6 mRNA levels are reverse transcription-polymerase chain reaction reagents.

6. The in vitro diagnostic kit for predicting or assessing the risk of secondary cognitive impairment in COPD patients according to claim 3, characterized in that, It also includes the reagent for detecting stearic acid levels and the reagent for detecting ELOVL6 protein or its mRNA levels.

7. A method for predicting the risk of secondary cognitive impairment in COPD patients, characterized in that, Includes the following steps: (a) Obtain serum samples from the COPD patients to be tested; (b) Detect the expression levels of stearic acid and / or ELOVL6 in the serum samples; (c) Compare the detected expression levels with a preset threshold; (d) Based on the comparison results, determine the risk level of secondary CI in the COPD patient. Among them, the expression levels of stearic acid and / or ELOVL6 are higher than the preset threshold, which indicates an increased risk of secondary CI.

8. The method for predicting the risk of secondary cognitive impairment in COPD patients according to claim 7, characterized in that, The preset threshold was determined based on statistical analysis of the expression levels of stearic acid and / or ELOVL6 in the serum of healthy controls or COPD patients who have not developed CI.

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