Circulating CCRR serves as potential novel biomarker for predicting acute myocardial infarction

Objective:Cold regions exhibit a high prevalence of cardiovascular disease,particularly acute myocardial infarction(AMI),which is one of the leading causes of death associated with cardiovascular conditions.Cardiovascular disease is closely linked to the abnormal expression of long non-coding RNA(lncRNA).This study investigates whether circulating levels of lncRNA cardiac conduction regulatory RNA(CCRR)could serve as a biomarker for AMI.Materials and methods:We measured circulating CCRR from whole blood samples collected from 68 AMI patients and 69 non-AMI subjects.An AMI model was established using C57BL/6 mice.Quantitative reverse transcription PCR(qRT-PCR)was used to assess CCRR expression.Exosomes were isolated from cardiomyocytes,and their characteristics were evaluated using electron microscope and nanoparticle tracking analysis.The exosome inhibitor GW4869 was employed to examine the effect of exosomal CCRR on cardiac function using echocardiography.Protein expression was detected using Western blot and immunofluorescence staining.Results:The circulating level of CCRR was significantly higher in AMI patients(1.93±0.13)than in non-AMI subjects(1.00±0.05,P<0.001).The area under the ROC curve(AUC)of circulating CCRR was 0.821.Similar changes in circulating CCRR levels were consistently observed in an AMI mouse model.Exosomal CCRR derived from hypoxia-induced cardiomyocytes and cardiac tissue after AMI were increased,a change that was reversed by GW4869.Additionally,CCRR-overexpressing exosomes improved cardiac function in AMI.Conclusion:Circulating lncRNA CCRR is a potential predictor of AMI.Exosomal CCRR plays a role in the communication between the heart and other organs through circulation.

Comparison of Effects of Mechanical Stretching on Osteogenic Potential of ASCs and BMSCs

Mechanical forces play critical roles in the development and remodeling processes of bone. As an alternative cell source for bone engineering, adipose-derived stem cells （ASCs） should be fully investigated for their responses to mechanical stress. Similarly, the osteogenic potential, stimulated by mechanical stress, should be compared with bone marrow stromal cells （BMSCs）, which have been clinically used for bone tissue engineering. In this study, ASCs and BMSCs were osteogenic-induced for 48 hours, and then subjected to uniaxial mechanical stretching for 2 or 6 hours. Cell orientation, osteogenic regulatory genes, osteogenic genes and ALP activities were measured and compared between ASCs and BMSCs. ASCs could align in a perpendicular way to the direction of stretching stress, while BMSCs did not present a specific alignment. Both 2 and 6 hours mechanical stretching could enhance the mRNA expression of Osx and Runx2 in BMSCs and ASCs, while OCN mRNA only increased in ASCs after 6 hours mechanical loading. Mechanical stretching enhanced the BMP-2 mRNA expression in ASCs, while only after 6 hours of mechanical loading significantly increased the BMP-2 gene expression in BMSCs. Significant differences only exist between ASCs and BMSCs loaded at 2 hours of mechanical stretching. It is concluded that ASCs are more rapid responders to mechanical stress, and have greater potential than BMSCs in osteogenesis when stimulated by mechanical stretching, indicating their usefulness for bone study in a rat model.