{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,7]],"date-time":"2026-02-07T21:29:58Z","timestamp":1770499798086,"version":"3.49.0"},"reference-count":27,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2025,9,23]],"date-time":"2025-09-23T00:00:00Z","timestamp":1758585600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Deanship of Scientific Research at Jouf University","award":["39\/589"],"award-info":[{"award-number":["39\/589"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cells"],"abstract":"<jats:p>Globally acute myocardial infarction is the leading independent cause of unexpected death. This study aimed to explore the diagnostic and molecular impact of miR-21, miR-488, and miR-126 in acute myocardial infarction patients (AMI). We enrolled 95 non-ST-elevation myocardial infarction (NSTEMI) patients, 152 ST-elevation myocardial infarction (STEMI) patients, and 95 healthy individuals, additionally using three-month-old mice and their ventricular-derived H9c2 cells. The circulatory plasma miR-21 and miR-488 levels were significantly upregulated, while plasma miR-126 levels were remarkably downregulated in NSTEMI and STEMI subjects. The receiver operating characteristic curve showed that plasma miR-21, miR-488, and miR-126 were able to clearly differentiate NSTEMI and STEMI from healthy subjects. Moreover, H9c2 hypoxic cells treated with inhibitor miR-21 markedly reduced intracellular ROS levels, capase-3 activities levels, and cellular apoptosis rates and significantly enhanced cellular viability through up regulation of Smad-7 mRNA and protein expressions. In geriatric STEMI and NSTEMI subjects, plasma miR-21 levels were evidently higher than in comparatively younger subjects. Upregulated plasma miR-21 and miR-488 levels and downregulated miR-126 levels might be considered potential clinical biomarkers for myocardial infarction patients, while inhibition of miR-21, which significantly reduced hypoxia-exposed H9c2 cellular injury via targeting Smad-7, could be a new therapeutic target for AMI patients. Low levels plasma miR-21 may have a significant impact on delaying the aging process.<\/jats:p>","DOI":"10.3390\/cells14191483","type":"journal-article","created":{"date-parts":[[2025,9,23]],"date-time":"2025-09-23T08:09:42Z","timestamp":1758614982000},"page":"1483","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["MicroRNA-21 Protects Hypoxic-Induced Cardiomyocytes Injury by Targeting Smad-7"],"prefix":"10.3390","volume":"14","author":[{"given":"Md Sayed","family":"Ali Sheikh","sequence":"first","affiliation":[{"name":"Internal Medicine Department, College of Medicine, Jouf University, Sakaka 72345, Saudi Arabia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"A.","family":"Alduraywish","sequence":"additional","affiliation":[{"name":"Internal Medicine Department, College of Medicine, Jouf University, Sakaka 72345, Saudi Arabia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Basil","family":"Mohammed Alomair","sequence":"additional","affiliation":[{"name":"Internal Medicine Department, College of Medicine, Jouf University, Sakaka 72345, Saudi Arabia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Muhannad","family":"Almubarak","sequence":"additional","affiliation":[{"name":"Internal Medicine Department, College of Medicine, Jouf University, Sakaka 72345, Saudi Arabia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Umme","family":"Salma","sequence":"additional","affiliation":[{"name":"Gynecology and Obstetrics Department, College of Medicine, Jouf University, Sakaka 72345, Saudi Arabia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,9,23]]},"reference":[{"key":"ref_1","first-page":"e41","article-title":"2025 Heart Disease and Stroke Statistics: A Report of US and Global Data From the American Heart Association","volume":"8","author":"Martin","year":"2025","journal-title":"Circulation"},{"key":"ref_2","first-page":"3000605241279190","article-title":"Impact of microRNAs on cardiovascular diseases and aging","volume":"10","author":"Sayed","year":"2024","journal-title":"J. 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