mastRNAs used for the diagnosis, screening, or assessment of acute coronary syndrome and their applications

Abstract

This invention belongs to the field of biomedical technology and discloses a mascRNA for the diagnosis, screening, or assessment of acute coronary syndrome (ACS) and its application in the preparation of products for diagnosing, screening, or assessing the prognosis of ACS. The novel biomarker mascRNA provided by this invention exhibits excellent stability, bringing convenience and low-invasiveness to the diagnosis of ACS. Its differential expression in plasma exosomes of patients with ACS and those with normal coronary arteries has significant value in the clinical diagnosis of ACS (AUC 0.763, 95% CI 0.702–0.824). Kaplan-Meier analysis and log-rank test data show that patients with high mascRNA expression have a lower MACE-free survival rate compared to patients with low mascRNA expression (P<0.001).

Description

Technical Field

[0001] This invention belongs to the field of biomedical technology, and specifically relates to a mascRNA for diagnosing, screening or assessing acute coronary syndrome and its application in the preparation of products for diagnosing, screening or assessing acute coronary syndrome. Background Technology

[0002] In recent years, cardiovascular diseases, primarily atherosclerotic cardiovascular disease (ASCVD), have accounted for over 40% of deaths. Acute coronary syndrome (ACS) is a severe manifestation of ASCVD, characterized by acute myocardial ischemia resulting from the rupture or invasion of atherosclerotic plaques in the coronary arteries, leading to complete or incomplete occlusion and thrombus formation. ACS includes ST-segment elevation myocardial infarction (STEMI), non-ST-segment elevation myocardial infarction (NSTEMI), and unstable angina (UA). ACS presents with complex and diverse symptoms, mainly paroxysmal chest pain and tightness. The condition typically develops suddenly and changes rapidly; without timely and effective treatment, it can lead to serious complications such as arrhythmias and heart failure, and in severe cases, even death. Therefore, early diagnosis and treatment of this disease are directly related to patient prognosis and survival rates.

[0003] Currently, the clinical diagnosis of ACS is usually based on the patient's clinical symptoms, characteristic changes on electrocardiogram (ECG), myocardial enzyme levels, and imaging studies such as coronary angiography and coronary vascular imaging to assist in diagnosis. Most ACS patients present to the emergency department with chest pain or tightness as their chief complaint, leading to an initial diagnosis. However, some patients present with atypical clinical symptoms, making early diagnosis difficult. Coronary angiography, considered the "gold standard" for diagnosing ACS, is highly valuable, but it is invasive and subject to limitations in medical resources and cost, resulting in limited flexibility and convenience. While current laboratory tests for myocardial necrosis markers such as troponin I (cTnI), creatine kinase (CK), and creatine kinase isoenzyme (CKMB) show early and prolonged elevation, the rapid progression of ACS means that changes in these markers lag behind the disease's progression, leading to diagnostic delays and missed diagnoses. Therefore, there is a need to find a biomarker that can facilitate early and rapid diagnosis of ACS and timely assessment of its severity.

[0004] MALAT1-associated small cytoplasmic RNA (mascRNA) is a highly conserved tRNA-like small non-coding RNA composed of 61 nucleotides, derived from the post-transcriptional processing of the initial lncRNA MALAT1 transcript. Studies have shown that MALAT1 is widely involved in tumorigenesis and development, as well as other cellular processes, such as regulating lipopolysaccharide-induced inflammatory responses. MascRNA has also recently been shown to promote tumor cell proliferation and migration. Given that mascRNA is primarily highly expressed in immune cells such as monocytes and macrophages, its regulatory role in immune function has attracted considerable attention. Studies have reported that knockdown of mascRNA affects the expression of multiple immune genes in monocytes, while exogenous mascRNA can enhance the resistance of cardiomyocytes to viral infections. However, there are currently no reports indicating a correlation between mascRNA and the diagnosis or prognosis of ACS. Summary of the Invention

[0005] In order to overcome the shortcomings and deficiencies of the prior art, the purpose of this invention is to provide an application of mascRNA (MALAT1-associated cytoplasmic small RNA) in the preparation of products for the diagnosis, screening or assessment of the prognosis of acute coronary syndrome.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] In a first aspect, the present invention provides the use of mascRNA (MALAT1-associated cytoplasmic small RNA) in the preparation of any of the following products:

[0008] (1) Diagnosis of acute coronary syndrome;

[0009] (2) Screening for acute coronary syndrome;

[0010] (3) Assess the prognosis of acute coronary syndrome.

[0011] Furthermore, the product includes reagents for detecting mascRNA expression levels.

[0012] Furthermore, the mascRNA is specifically present in plasma.

[0013] Furthermore, the expression level of mascRNA in patients with acute coronary syndrome was significantly higher than that in patients with normal coronary arteries.

[0014] Furthermore, the expression level of mascRNA in the plasma of patients with acute coronary syndrome was significantly higher than that in patients with normal coronary arteries.

[0015] Furthermore, the expression level of mascRNA in plasma exosomes of patients with acute coronary syndrome was significantly higher than that of patients with normal coronary arteries.

[0016] This invention detects the expression level of mascRNA in plasma exosomes of patients with coronary syndrome and those with normal coronary arteries. Results show that compared with those with normal coronary arteries, patients with acute coronary syndrome exhibit significantly increased mascRNA expression in peripheral blood plasma exosomes, with good stability and diagnostic performance. Detecting mascRNA expression levels has significant advantages in diagnosing acute coronary syndrome, including ease of operation, minimal invasiveness, and no radiation hazard, overcoming the limitations of traditional diagnostic methods. ROC curves showed an AUC of 0.763, with a 95% CI of 0.702–0.824. Kaplan-Meier analysis and log-rank test data showed that patients with high mascRNA expression had a lower MACE-free survival rate compared to those with low mascRNA expression (P<0.001). Cox regression analysis showed that after adjusting for age, diabetes, and LVEF, mascRNA was significantly associated with the occurrence of 1-year MACEs, with a HR of 2.959 and a 95% CI of 1.187–4.669 (P<0.001). This indicates that mascRNA has good clinical application value in screening and assessing the prognosis of acute coronary syndrome and is suitable for widespread application in clinical practice.

[0017] Based on this, the present invention proposes for the first time a biomarker mascRNA for diagnosing, screening or assessing the prognosis of acute coronary syndrome, provides a mascRNA-based diagnostic method for acute coronary syndrome, and proposes the application of mascRNA (MALAT1-associated cytoplasmic small RNA) in the preparation of products for diagnosing, screening or assessing the prognosis of acute coronary syndrome.

[0018] Furthermore, the product may include at least one of the following: chip, formulation, reagent kit, test strip, or high-throughput sequencing platform.

[0019] Furthermore, the product can diagnose, screen, or assess the prognosis of acute coronary syndrome by detecting the expression level of mascRNA in a sample.

[0020] Secondly, the present invention also provides the use of the product for detecting mascRNA expression levels in the preparation of any of the following products:

[0021] (1) Diagnosis of acute coronary syndrome;

[0022] (2) Screening for acute coronary syndrome;

[0023] (3) Assess the prognosis of acute coronary syndrome.

[0024] Furthermore, the products for detecting mascRNA expression levels include those that detect mascRNA expression levels using methods such as RT-PCR, quantitative real-time PCR, immunoassay, in situ hybridization, microarray, or high-throughput sequencing platforms.

[0025] Furthermore, the product for detecting mascRNA expression levels by RT-PCR includes at least one pair of primers that specifically amplify mascRNA.

[0026] Furthermore, the product for detecting mascRNA expression levels by quantitative real-time PCR includes at least one pair of primers that specifically amplify mascRNA.

[0027] Furthermore, the sources of the mascRNAs and their expression products used for diagnosing, screening, or assessing acute coronary syndrome include, but are not limited to, bodily fluids such as blood, tissue fluid, urine, saliva, and cerebrospinal fluid. In a specific embodiment of the present invention, the source of the mascRNAs and their expression products used for diagnosing, screening, or assessing the prognosis of acute coronary syndrome is blood. Further, the sample is peripheral venous blood. Even further, the sample is exosomes in plasma.

[0028] Furthermore, the expression level of mascRNA was detected in plasma exosomes of patients with acute coronary syndrome and those with normal coronary arteries using the above-mentioned products for diagnosis. The results showed that the expression level of mascRNA was significantly increased in patients with acute coronary syndrome.

[0029] Thirdly, the present invention also provides the application of mascRNA in the preparation of a real-time PCR kit for diagnosing acute coronary syndrome.

[0030] Furthermore, the kit includes at least one pair of primers specifically amplifying mascRNA, with sequences shown in SEQ ID NO.1 and SEQ ID NO.2.

[0031] Forward primer 5'-GATGCTGGTGGTTGGCACTC-3' (SEQ ID NO.1);

[0032] Reverse primer 5'-TGGAGACGCCGCAGGGAT-3' (SEQ ID NO.2).

[0033] Fourthly, the present invention provides a real-time PCR kit for diagnosing acute coronary syndrome.

[0034] Furthermore, the kit includes at least one pair of primers specifically amplifying mascRNA, with sequences shown in SEQ ID NO.1 and SEQ ID NO.2.

[0035] Furthermore, the kit also includes a pair of primers for specifically amplifying the internal control U6, the sequences of which are shown in SEQ ID NO.3 and SEQ ID NO.4.

[0036] Forward primer 5'-CTCGCTTCGGCAGCACA-3' (SEQ ID NO.3);

[0037] Reverse primer 5'-AACGCTTCACGAATTTGCGT-3' (SEQ ID NO.4).

[0038] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0039] This invention provides a novel biomarker, mascRNA, for the diagnosis of acute coronary syndrome (ACS), exhibiting excellent stability and offering convenience and low invasiveness for ACS diagnosis. This invention reveals differences in mascRNA levels in plasma exosomes between patients with ACS and those with normal coronary arteries, demonstrating significant clinical diagnostic value for ACS (AUC 0.763, 95% CI 0.702–0.824). Kaplan-Meier analysis and log-rank test data show that patients with high mascRNA expression had a lower MACE-free survival rate compared to those with low mascRNA expression (P<0.001). Cox regression analysis showed that, after adjusting for age, diabetes, and LVEF, mascRNA was significantly associated with the occurrence of 1-year MACEs (HR 2.959, 95% CI 1.187–4.669, P<0.001). This indicates that mascRNA has good clinical application value in screening and assessing the prognosis of acute coronary syndrome, and that detecting mascRNA expression level has significant advantages in diagnosing acute coronary syndrome, including convenient operation, minimal invasiveness and no radiation hazard, overcoming the limitations of traditional diagnostic methods, and is suitable for widespread application in clinical practice. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 A schematic diagram of the research process of this invention.

[0042] Figure 2 Centrifugation protocol for enriching plasma exosomes.

[0043] Figure 3 For the identification of exosomes. Among them, A is the analysis of exosome morphology by transmission electron microscopy (TEM); B is the Western blot analysis of exosome markers; C is the determination of exosome particle size by nanoparticle tracking analysis.

[0044] Figure 4 The expression of mascRNA in exosomes in ACS patients is shown. A represents the expression level of mascRNA in exosomes of ACS patients and non-ACS patients; B represents the expression level of mascRNA in exosomes of ACS patients who experienced MACE and those who did not during a 1-year follow-up period.

[0045] Figure 5 The correlation between mascRNA expression levels in exosomes and Gensini.

[0046] Figure 6 The diagnostic value of mascRNA expression levels in exosomes for ACS.

[0047] Figure 7 To determine the predictive value of mascRNA expression levels in exosomes for the prognosis of ACS patients.

[0048] Among them, *P<0.05, **P<0.01. Detailed Implementation

[0049] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0050] To facilitate understanding of the present invention, a more comprehensive description is provided below in conjunction with preferred embodiments and accompanying drawings. It should be understood that the specific descriptions below are illustrative rather than restrictive and should not be construed as limiting the scope of protection of the present invention.

[0051] Patients diagnosed with acute coronary syndrome (ACS) met the diagnostic criteria for ACS established by the American Heart Association (AHA) and the American College of Cardiology (ACC), with patients experiencing chest pain but without ACS and having normal coronary arteries serving as controls. Exclusion criteria included: a history of severe valvular heart disease, structural heart disease, severe arrhythmias, acute or chronic inflammation, malignancy, severe liver or kidney dysfunction, autoimmune diseases, and hematologic disorders. The patient inclusion process can be found here. Figure 1 .

[0052] Example 1: Isolation, identification, and expression of exosomal mascRNA in plasma of patients with acute coronary syndrome and those with normal coronary arteries.

[0053] 1. Research Subjects

[0054] This study included 190 participants, all of whom provided specimens from Meizhou People's Hospital. Patients with normal coronary arteries were matched with those with coronary atherosclerosis (ACS) based on five variables: age, sex, hypertension, diabetes, and hyperlipidemia. Ultimately, 140 ACS patients were matched, and 50 were controls. The study protocol was approved by the local ethics committee and conducted in accordance with the ethical standards outlined in the Declaration of Helsinki (Approval No.: 2023-C-34). Informed consent was obtained from the patients. Patient baseline data are shown in Table 1.

[0055] Table 1

[0056]

[0057]

[0058] Note: LVEF: Left ventricular ejection fraction; TG: Triglycerides; TC: Total cholesterol; LDL-C: Low-density lipoprotein cholesterol; HDL-C: High-density lipoprotein cholesterol; WBC: White blood cells; cTnI: Cardiac troponin I; NA: Not applicable.

[0059] 2. Specimen Collection

[0060] 2.1 Sample preparation: Venous blood was collected from the patient upon admission and placed in a blood collection tube containing EDTA anticoagulant. The tube was inverted and mixed to prevent blood clotting.

[0061] 2.2 Plasma separation: The collected blood samples were centrifuged at 2500g for 15min at room temperature to remove cells and cell debris, and the plasma was separated. All supernatant (i.e., plasma) was transferred to a new centrifuge tube.

[0062] 2.3 Low-speed centrifugation: Place the plasma sample at 4°C and centrifuge at 300g for 10 min to remove residual cells and large particles. After centrifugation, carefully transfer the supernatant to a new sterile centrifuge tube and discard the precipitate.

[0063] 2.4 Medium-speed centrifugation: Centrifuge at 2000g for 10 min at 4℃ to remove dead cell debris and larger particles. After centrifugation, place the centrifuge tube in an ice bath and slowly pour the supernatant into a new sterile centrifuge tube.

[0064] 2.5 High-speed centrifugation: Centrifuge at 10000g for 10 min at 4℃ to further remove cell debris and larger impurity particles. After centrifugation, slowly pour the supernatant into a new sterile centrifuge tube and discard the precipitate.

[0065] 2.6 Ultracentrifugation: Centrifuge at 120,000 g for 30 min at 4℃ to allow exosomes to settle, and collect the precipitate to obtain the exosomes;

[0066] 2.7 Exosome washing and resuspending: Add pre-chilled PBS to a centrifuge tube, gently vortex or tap the bottom of the tube to resuspend the exosome precipitate. Centrifuge the suspension at 120,000 g for 30 min. After centrifugation, carefully discard the supernatant and resuspend the exosomes in 100 μL PBS. Store at -80℃ for later use (see diagram for exosome collection and separation). Figure 2 ).

[0067] 3. Exosome extraction and identification

[0068] Transmission electron microscopy (TEM), nanoparticle tracking analysis, and Western blotting (WB) were used to identify the isolated exosomes. TEM revealed that the exosomes exhibited a typical bilayered vesicle structure, appearing as round or near-round vesicles. Figure 3 A); Western blot results showed that high abundances of exosomal marker proteins CD9, TSG101, and CD63 were detected in the isolated plasma exosomes. Figure 3 B), and these proteins were not detected in the exosome removal supernatant; nanoparticle tracking analysis: the average diameter of vesicles in the sample was 130 nm. Figure 3 C).

[0069] 4. Determination of the relative expression level of exosomal mascRNA

[0070] The relative expression level of mascRNA in plasma exosomes was determined by real-time quantitative polymerase chain reaction (qRT-PCR): exosomal RNA was extracted using the SteadyPure small RNA extraction kit (Accurate Biology, China).

[0071] 4.1 Exosomal RNA Extraction: Total exosomal RNA was extracted using the SteadyPure Small RNA Extraction Kit from Aikerui Biotechnology. The exosomal precipitate obtained by ultracentrifugation was collected, and 1 mL of lysis buffer was added. The mixture was then pipetted and allowed to stand at room temperature for 2 min. 200 μL of chloroform was added to the lysis buffer, and the mixture was thoroughly mixed and allowed to stand at room temperature for 5 min. The centrifuge tubes were then centrifuged at 12000 g at 4℃ for 15 min. 450 μL of the supernatant was transferred to a new centrifuge tube, and 225 μL of anhydrous ethanol was slowly added. The mixture was then pipetted and allowed to mix thoroughly. The concentration and purity of the total RNA were determined using a Nano Drop 2000.

[0072] 4.2 Reverse transcription to synthesize cDNA

[0073] ① Retrieve PrimeScript TM RT reagent kit (TaKaRa, Dalian, China), briefly centrifuged and placed on ice. Prepare reverse transcription reaction solutions according to the components in Table 2. Reagent preparation was performed on ice.

[0074] Table 2 Reverse transcription reaction system

[0075] 5×PrimeScript RT Master Mix 2μL Total RNA 300ng-500ng <![CDATA[RNase Free dH2O]]> up to 10μL

[0076] ② After gently mixing the prepared solution, turn on the PCR instrument and set the cycle as follows. Place the samples one by one into the instrument and start the reverse transcription reaction. The reverse transcription reaction program is: 37℃ for 15 min, 85℃ for 5 s. After the reaction is complete, promptly remove the reverse transcription reaction solution, which is the synthesized cDNA.

[0077] 4.3 Real-time quantitative PCR (RT-qPCR) detection

[0078] RT-qPCR was performed using TB Green Premix Ex Taq II (Tli RNaseH Plus), with U6 as an internal control. The relative expression levels of mascRNA genes in plasma exosomes from different groups were detected by RT-qPCR, and the expression differences between groups were compared. The nucleotide sequences of the mascRNA-specific amplification primers are shown in SEQ ID NO.1 and SEQ ID NO.2. The nucleotide sequences of the U6-specific amplification primers are shown in SEQ ID NO.3 and SEQ ID NO.4.

[0079] Prepare the RT-qPCR reaction system according to the proportions in Table 3, and perform the reagent preparation on ice:

[0080] Table 3 RT-qPCR reaction system

[0081] TBGreenPremixExTaqII(TliRNaseHPlus) 10μL PCRForwardPrimer (10μM) 1μL PCRReversePrimer (10μM) 1μL cDNA template 2μL <![CDATA[RNaseFreedH2O]]> 6μL Total 20μL

[0082] RT-qPCR was performed using a two-step method, and melting curves were generated. The program settings are shown in Table 4.

[0083] Table 4. Two-step RT-qPCR reaction system program settings

[0084]

[0085] After the reaction was completed, the relative expression level of the mascRNA gene was calculated using 2-ΔΔCt based on the original RT-qPCR detection results, with U6 as an internal reference.

[0086] 5. The diagnostic efficacy of exosomal mascRNA for ACS patients was evaluated using ROC curve analysis and AUC (area under the curve). Results are shown in [Figure number missing]. Figure 4 and Figure 5 .

[0087] 6. Correlation between exosomal mascRNA expression levels and the risk of ACS

[0088] All patients' clinical coronary angiography results were collected. Coronary artery stenosis scores (modified Gensini score) were calculated based on these results. The scoring method was as follows: the degree and severity of proximal coronary artery lesions were scored for each lesion site: less than 50% luminal diameter stenosis, 1 point; 50%-74% stenosis, 2 points; 75%-99% stenosis, 3 points; complete occlusion, 4 points. The scores for each lesion in the proximal coronary circulation were summed to obtain the final overall score (Gensini score) for the severity of coronary atherosclerosis. Spearman correlation analysis was used to detect the correlation between exosomal mascRNA and the Gensini score. Simultaneously, a multivariate logistic regression model was used to assess the correlation between exosomal mascRNA and the risk of ACS.

[0089] 7. The evaluative value of exosomal mascRNA in ACS patients one year after PCI

[0090] Patients with acute coronary syndrome (ACS) were followed up for one year after percutaneous coronary intervention (PCI) via electronic medical records or telephone follow-up. The primary outcome measure was the incidence of major adverse cardiovascular events (MACEs), including all-cause mortality, non-fatal myocardial infarction, target vessel revascularization, rehospitalization for angina or heart failure, and stent thrombosis. Kaplan-Meier analysis and log-rank test were used to assess 1-year MACE-free survival in the high and low mascRNA groups. Multivariate Cox regression analysis was used to analyze the relationship between exosomal mascRNA and MACEs in ACS patients.

[0091] 8. Results Analysis

[0092] 8.1 Expression of exosomal mascRNA in ACS patients:

[0093] Depend on Figure 4 It is evident that, compared to non-ACS patients, ACS patients exhibit elevated exosomal mascRNA expression. Figure 4 A). Comparing exosomal mascRNA expression in patients with and without MACEs during a 1-year follow-up after PCI, the mascRNA expression in the MACE group was significantly higher than that in the non-MACE group. Figure 4 B). Further analysis of the correlation between exosomal mascRNA and clinical parameters: Spearman correlation analysis showed that exosomal mascRNA levels were significantly positively correlated with Gensini scores (r = 0.242, P < 0.001). Figure 5 ).

[0094] 8.3 Association between exosomal mascRNA expression levels and the risk of ACS:

[0095] ROC curve analysis showed that exosomal mascRNA could serve as a diagnostic predictor of ACS, with an AUC of 0.763 and a 95% CI of 0.702–0.824. Figure 6 The association between exosomal mascRNA and ACS was assessed using a multivariate logistic regression model. The results showed that patients in the second, third, and fourth quartiles of mascRNA expression had an increased risk of developing ACS compared to patients in the first quartile (Q1) (OR: 3.423, 95% CI: 1.427–8.213; OR: 5.542, 95% CI: 1.859–16.524; OR: 9.288, 95% CI: 3.275–26.340; all P < 0.01; Table 5).

[0096] Table 5. Relationship between exosomal mascRNA expression and the risk of ACS.

[0097]

[0098]

[0099] *Adjusted for age, sex, hypertension, and diabetes.

[0100] 8.4 Predictive value of exosomal mascRNA for major cardiovascular events one year after PCI in ACS patients:

[0101] Patients were divided into a high mascRNA group (≥3.85, n=60) and a low mascRNA group (<3.85, n=60). Kaplan-Meier analysis and log-rank test were used to assess the 1-year MACE-free survival in the high and low mascRNA groups. Data showed that patients with high mascRNA expression had a lower MACE-free survival rate compared to patients with low mascRNA expression (long rank P<0.001). Figure 7 Multivariate Cox regression analysis was used to analyze the relationship between exosomal masc RNA and MACEs in patients with ACS. After adjusting for age, diabetes, and LVEF, masc RNA was significantly associated with the occurrence of 1-year MACEs, with a HR of 2.959 and a 95% CI of 1.187–4.669 (P<0.001) (Table 6).

[0102] Table 6. Multivariate Cox regression model analysis of MACEs in ACS patients.

[0103] Age (years) 1.047 1.008-1.087 0.016 1.038 1.005-1.073 0.031 Gender (Male / Female) 1.577 0.702-3.543 0.270 hypertension 0.714 0.348-1.464 0.358 diabetes 0.873 0.357-2.136 0.766 0.529 0.198-1.412 0.204 Dyslipidemia (%) 1.024 0.479-2.188 0.951 LVEF (%) 0.954 0.929-0.980 0.001 0.955 0.931-0.979 <0.001 Number of stents 0.995 0.564-1.754 0.986 support length 1.008 0.986-1.030 0.494 MascRNA(log10) 3.357 2.042-5.520 <0.001 2.959 1.187-4.669 <0.001

[0104] *Adjusted for age, diabetes, and LVEF.

[0105] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. Application of mascRNA in the preparation of any of the following products: (1) Diagnosis of acute coronary syndrome; (2) Screening for acute coronary syndrome.

2. The application according to claim 1, characterized in that: The expression level of mascRNA in patients with acute coronary syndrome was significantly higher than that in patients with normal coronary arteries.

3. The application according to claim 1, characterized in that: The product includes at least one of a chip, a reagent kit, or a high-throughput sequencing platform.

4. The application according to claim 1, characterized in that: The product diagnoses or screens for acute coronary syndrome by detecting the expression level of mascRNA in samples.

5. Application of products for detecting mascRNA expression levels in the preparation of any of the following products: (1) Diagnosis of acute coronary syndrome; (2) Screening for acute coronary syndrome.

6. The application according to claim 5, characterized in that... The products for detecting mascRNA expression levels include those that detect mascRNA expression levels using RT-PCR, quantitative real-time PCR, microarray, or high-throughput sequencing platforms.

7. Application of mascRNA in the preparation of a real-time PCR kit for diagnosing acute coronary syndrome.

8. The application according to claim 7, characterized in that: The kit includes at least one pair of primers for specifically amplifying mascRNA, with sequences shown in SEQ ID NO.1 and SEQ ID NO.2.

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