Possibilities and limitations for co-transplantation of cardiac atrial appendage stem cells and mesenchymal stem cells for myocardial repair

LARIAT or AtriClip: Complications Profile and Comparison in Patients with Atrial Fibrillations Based on Manufacturer and User Facility Device Experience Database

Background and Objectives: Left atrial appendage closure is an alternative treatment to reduce thromboembolism in patients with atrial fibrillation in whom oral anticoagulation (OAC) is contraindicated. The aim of this study was to evaluate the complications profiles of the LARIAT and AtriClip devices and perform a comparison between them based on the MAUDE (Manufacturer and User Facility Device Experience) database. Materials and Methods: The Manufacturer and User Facility Device Experience database was searched on 15 January 2023. For AtriClip, only reports regarding isolated procedures or procedures associated with minimally invasive ablation were included. Adverse effects and causes of death were defined based on the literature on the topic and the causes described in the reports. In total, 63 patients were included in the LARIAT group and 53 patients were included in the AtriClip group. Results: With the LARIAT device, the most common complication without device problems was pericardial effusion (n = 18, 52.9%), whereas this complication was not observed with AtriClip (p < 0.001). Postoperative bleeding was a second complication that occurred significantly more often in the LARIAT group-in 15 (44.1%) cases versus 1 (2.7%) case with AtriClip (p < 0.001). In addition, significant differences were found in the prevalence of stroke (LARIAT n = 0 vs. AtriClip n = 7, 18.9%, p = 0.012) and thrombus (LARIAT n = 2, 5.9% vs. n = 11, 29.7%, p = 0.013). Conclusions: Each type of left atrial appendage closure procedure is associated with device-specific requirements and complications that, if known, can be avoided.

Nonthrombogenic Roles of the Left Atrial Appendage: JACC Review Topic of the Week

The atrial appendage (LAA) is a well-established source of cardioembolism in patients with atrial fibrillation. Therefore, research involving the LAA has largely focused on its thrombogenic attribute and the utility of its exclusion in stroke prevention. However, recent studies have highlighted several novel functions of the LAA that may have important therapeutic implications. In this paper, we provide a concise overview of the LAA anatomy and summarize the emerging data on its nonthrombogenic roles.

How to Stimulate Myocardial Regeneration in Adult Mammalian Heart: Existing Views and New Approaches

Stem cell-based therapy has been considered as a promising option in the treatment of ischemic heart disease. Although stem cell administration resulted in the temporary improvement of myocardial contractility in the majority of studies, the formation of new cardiomyocytes within the injured myocardium has not been conclusively demonstrated. Consequently, the focus of research in the field has since shifted to stem cell-derived paracrine factors, including cytokines, growth factors, mRNA, and miRNA. Notably, both mRNA and miRNA can enter into the extracellular space either in soluble form or packed into membrane vesicles. Stem cell-derived paracrine factors have been shown to suppress inflammation and apoptosis, stimulate angiogenesis, and amplify the proliferation and differentiation of resident cardiac stem cells (CSCs). Such features have led to exosomes being considered as potential drug candidates affording myocardial regeneration. The search for chemical signals capable of stimulating cardiomyogenesis is ongoing despite continuous debates regarding the ability of mature cardiomyocytes to divide or dedifferentiate, transdifferentiation of other cells into cardiomyocytes, and the ability of CSCs to differentiate into cardiomyocytes. Future research is aimed at identifying novel cell candidates capable of differentiating into cardiomyocytes. The observation that CSCs can undergo intracellular development with the formation of “cell-in-cell structure” and subsequent release of transitory amplifying cells with the capacity to differentiate into cardiomyocytes may provide clues for stimulating regenerative cardiomyogenesis.