Generation of Cardiomyocytes From Vascular Adventitia-Resident Stem Cells.

RATIONALE: Regeneration of lost cardiomyocytes is a fundamental unresolved problem leading to heart failure. Despite several strategies developed from intensive studies performed in the past decades, endogenous regeneration of heart tissue is still limited and presents a big challenge that needs to be overcome to serve as a successful therapeutic option for myocardial infarction. OBJECTIVE: One of the essential prerequisites for cardiac regeneration is the identification of endogenous cardiomyocyte progenitors and their niche that can be targeted by new therapeutic approaches. In this context, we hypothesized that the vascular wall, which was shown to harbor different types of stem and progenitor cells, might serve as a source for cardiac progenitors. METHODS AND RESULTS: We describe generation of spontaneously beating mouse aortic wall-derived cardiomyocytes without any genetic manipulation. Using aortic wall-derived cells (AoCs) of WT (wild type), αMHC (α-myosin heavy chain), and Flk1 (fetal liver kinase 1)-reporter mice and magnetic bead-associated cell sorting sorting of Flk1+ AoCs from GFP (green fluorescent protein) mice, we identified Flk1+CD (cluster of differentiation) 34+Sca-1 (stem cell antigen-1)-CD44- AoCs as the population that gives rise to aortic wall-derived cardiomyocytes. This AoC subpopulation delivered also endothelial cells and macrophages with a particular accumulation within the aortic wall-derived cardiomyocyte containing colonies. In vivo, cardiomyocyte differentiation capacity was studied by implantation of fluorescently labeled AoCs into chick embryonic heart. These cells acquired cardiomyocyte-like phenotype as shown by αSRA (α-sarcomeric actinin) expression. Furthermore, coronary adventitial Flk1+ and CD34+ cells proliferated, migrated into the myocardium after mouse myocardial infarction, and expressed Isl-1+ (insulin gene enhancer protein-1) indicative of cardiovascular progenitor potential. CONCLUSIONS: Our data suggest Flk1+CD34+ vascular adventitia-resident stem cells, including those of coronary adventitia, as a novel endogenous source for generating cardiomyocytes. This process is essentially supported by endothelial cells and macrophages. In summary, the therapeutic manipulation of coronary adventitia-resident cardiac stem and their supportive cells may open new avenues for promoting cardiac regeneration and repair after myocardial infarction and for preventing heart failure.

Precision Oncology in Pancreatic Cancer: Experiences and Challenges of the CCCMunichLMU Molecular Tumor Board.

BACKGROUND: In pancreatic cancer, systemic treatment options in addition to chemotherapy remain scarce, and so far only a small proportion of patients benefit from targeted therapies. OBJECTIVE: The patients with pancreatic cancer discussed in the CCCMunichLMU Molecular Tumor Board were reviewed to gain a better real-world understanding of the challenges and chances of precision oncology in this hard-to-treat cancer. METHODS: Patients with pancreatic cancer who received comprehensive genomic profiling and were discussed in the interdisciplinary Molecular Tumor Board between May 2017 and July 2022 were included. These patients' medical charts, comprehensive genomic profiling results, and Molecular Tumor Board recommendations were analyzed in this retrospective cohort study. RESULTS: Molecular profiles of 165 patients with pancreatic cancer were discussed in the Molecular Tumor Board. In the 149 cases where comprehensive genomic profiling was successful, KRAS mutations were detected in 87.9%, TP53 in 53.0%, and CDKN2A in 14.1%. 33.3% of KRAS wild-type patients harbored targetable mutations, while these were only found in 19.1% of patients with the KRAS mutation; however, this difference was not statistically significant. 63.8% of patients with successful testing received a targeted treatment recommendation by the Molecular Tumor Board; however, only 3.2% of these were put into practice. Compared to a historic cohort of patients with pancreatic cancer with synchronous metastatic disease diagnosed between 2010 and 2017, the patients from the pancreatic cancer cohort with synchronous metastatic disease had a longer survival. CONCLUSIONS: This single-center experience emphasizes the challenges of targeted treatment in pancreatic cancer. Very few patients ultimately received the recommended therapies, highlighting the need for more and better targeted treatment options in pancreatic cancer, early comprehensive genomic profiling to allow sufficient time to put Molecular Tumor Board recommendations into practice, and close cooperation with clinical trial units to give patients access to otherwise not available targeted treatments.