Past studies have shown that biomarkers in acute myocardial infarction, such as cardiac troponin and creatine kinase MB, do not rise significantly during the early diagnosis. Nowadays, with the advent of high-sensitivity cardiac troponin test, even within one hour, myocardial infarction can be diagnosed with reasonable accuracy. Nevertheless, looking for other early biomarkers, especially in different potential molecular mechanisms, may achieve higher sensitivity and specificity in short time. In the early diagnosis of stroke, the same problem is also faced, it is difficult to distinguish between transient ischemic attack and ischemic stroke within the time window of thrombolytic treatment. Although the latest imaging technology can be used in the time window, TIA is diagnosed complexity and high cost. These methods limit widespread and a variety of blood markers are used for the predictive value of TIA[12–13]. Recently studies have shown that myocardial infarction is highly correlated with the incidence of stroke and can be given by measuring MiR-122[14–15]. MiR-122 is a non-coding RNA that participates in the post-transcriptional regulation of gene expression by binding to target mRNA . MiR-122 can regulate lipid metabolism and the pathophysiological process of atherosclerosis in CCVD. The content shows stable changes in the serum of subjects. This feature may have potential value as a therapeutic target.
In this study, the value of MiR-122 in the diagnosis of CCVD was evaluated and analyzed through Meta analysis. It has shown that MiR-122 has a greater diagnostic value for predicting CCVD and its expression is elevated in diseases such as myocardial infarction, angina pectoris and stroke. The differences between the groups are statistically significant. In the evaluation of the diagnostic value of biomarkers, there are three main aspects that can lead to consensus among researchers[18–19]: 1. The biomarker can quickly diagnose acute and severe cardiovascular and cerebrovascular diseases and detect high-risk patients. 2. The biomarker has high specificity in cardiovascular and cerebrovascular diseases, and is less interfered by other diseases or the patient's own state. 3.The marker is easy to detect and the price is easy to accept. The results of this study have shown that, compared with the control group, MiR-122 is expressed in CCVD patients at a higher level. MiR-122 has a more accurate diagnostic value for the prognosis of patients and fulfills the above-mentioned specificity requirements. The study in Koyama et al. showed that compared with the control group, the level of miR-122 in patients with acute myocardial infarction was significantly higher. The level of miR-122 in patients with non-ST-segment elevation myocardial infarction was higher than ST-segment elevation myocardium patients with infarction at the peak of eight hours (P<0.05). Other studies have shown that MiR-122 can be obtained by real-time quantitative fluorescence polymerase chain reaction detection in the peripheral blood of patients. Its detection method is simple and quick, and has potential value as a cardio-cerebrovascular biomarker[21–22].
Although this study has been evaluated objectively, it still has deficiencies. The literature including the research is relatively few and it includes retrospective research, which may have an influence on the credibility of conclusions. Based on the sample estimation of 23 articles, the random allocation method of some articles is not standardized and the allocation concealment, blind method and review are lacking. Due to the lack of original data, it is difficult for us to restore the missing data. Nonetheless, our data shows that the heterogeneity of these studies has been corrected to the greatest extent by combining the data of the random effects model. And the funnel chart also shows that the conclusions are less biased.
In order to evaluate the diagnostic potential of MiR-122 in CCVD, further studies are still needed. Subsequent research should also pay attention to the correlation between MiR-122 and other cardiac biomarkers in various heart disease patients, as well as the correlation with plaque vulnerability. Therefore, it remains to be determined whether the differences in the plasma concentration and elevated dynamics of MiR-122 in the cardi-cerebrovascular systems can be used to identify the underlying pathophysiological mechanisms in different subdivisions. Whether these differences can be used to stratify risk groups accurately.