The Impact of Marijuana (<i>Cannabis sativa</i>) on Viability and Expression of Cardiac Markers in Human Cardiomyocytes

Abstract

Background: Cannabis sativa has been used since antiquity for medicinal, ceremonial, and agricultural purposes. Today, cannabis, commonly known as marijuana, remains the most widely used recreational drug worldwide. As its use increases, particularly among young adults, reports of adverse effects on vital organs have also increased. This trend underscores the need for a comprehensive assessment of marijuana’s effects on the cardiovascular system. Objectives: This study aimed to investigate the effects of C. sativa extract on the viability, proliferation, and expression of cardiac markers in human cardiomyocytes. Methods: Human cardiomyocytes (HCMs) were cultured and subsequently exposed to varying concentrations of cannabis extract. Cell viability was assessed using the MTT assay, and morphological changes were examined on days 3 and 6. Growth curves and population doubling times were determined over a 6-day period using the trypan blue exclusion method. In addition, the expression levels of cardiac-specific markers, including GATA4, troponin, and creatine kinase, were quantified using real-time polymerase chain reaction on days 1, 3, and 6. Results: No significant changes in cell morphology were observed; however, cell density was consistently higher in the treated group, particularly at early time points. Growth-curve analysis confirmed these findings, demonstrating higher cell numbers in treated cultures throughout the study period, consistent with the population doubling time data (74.79 h in the treated group vs. 80.45 h in the control group, P = 0.005). Furthermore, the treated group exhibited increased expression of cardiac-specific markers compared with the controls, most notably between day 1 and day 3 (GATA4: 7.97 ± 1.06 vs. 1.48 ± 0.64, P < 0.05; troponin: 3.52 ± 0.85 vs. 1.13 ± 0.92, P = 0.05; creatine kinase: 0.001 ± 0.0008 vs. 1.22 ± 0.90, P = 0.05). Conclusions: Cannabis sativa extract increased proliferation and upregulated the expression of cardiac genes in HCMs. These changes may impair normal cardiomyocyte function, which is vital for cardiovascular health. This issue is particularly important given the increasing global consumption of cannabis-derived substances, driven in part by expanding legalization.