Heart failure is a chronic disease caused by the dysfunction of the cardiac stem cells. Even though stem cell implantation is successful in the regeneration of the heart, heart failure remains the leading cause of death. However, the human heart contains heart stem cells, which can self-renew and recover heart vessels and cardiomyocytes. In this article,” Distribution of cardiac stem cells in the human heart,” Arsalan et al.  explore the distribution of human heart stem cells in various parts of the heart with flow cytometry guidance. This article aimed to use flow cytometry to identify and analyze the distribution of hCSCs. Using this method, the c-kit and the lineage of human cardiac stem cells were discovered. It was also noted that there was the absence of a strong distinction between the c-kit and the lineage cells, as seen in both atria. Even though the article showed significant results, the study had notable limitations related to sample size and study design.
The researchers used 20 tissue specimens taken from the left ventricle (LV), right atrium appendix (RA), and left atrium (LA) in adult patients undergoing a heart operation. The ages of the participants ranged between 67 and 2 years, and the specimen weight was from 0.36 until 0.09 g. The study was conducted through a case-control study design. Investigators used flow cytometry in which specimens were first measured and washed samples separately in Hank’s Balanced Salt Solution. They then carried out 15 min of sequential digestions with collagenase IV and trypsin. This was followed by centrifugation to separate the MNCs using a density gradient centrifuge over a cell strainer. These cells then contain some antibodies. Immunofluorescence treatment was performed when the phases were xylene, diluted with alcohol, dried for 10 minutes, then reheated in distilled water for a few minutes, and then washed with Tris-Buffered Saline for 10 minutes. The researchers then conducted Statistical Analyses using FACS Diva software for multivariate analysis and a one-way ANOVA for the statistical comparison. The results indicated that the human heart has Cardiac Stem Cells. Additionally, the authors found out that the Atria has more HCSCs than the left ventricle. Interestingly, the authors were unable to establish whether HCSCs originate from the heart muscle or bone marrow.
While the researchers established that the atria contain the highest human cardiac stem cells distribution, the outcomes faced two notable limitations. First of all, the authors used a small sample to determine the distribution of the human cardiac cells in the heart. For instance, only 20 specimens were used in the experiment. In expansion, numerous patients were 65 years or older. According to Faber and Fonseca , a small sample is likely to miss out on some basic characteristics of the larger population and limit the accuracy of discoveries and prevent generalization. Secondly, the authors carried out some tests and obtained various estimates. However, this study’s design lacked a control group. As such, they could not compare the distribution of human heart cells in the heart among the study group participants and healthy controls. In addition, they were unable to distinguish or assess the difference between the observation test and the measurements on the flow cytometric scale within the control group. According to Tadevosyan et al. , failure to include a control group limits the comparison of the tested variables in the experimental group and the healthy controls, limiting the accuracy of the results. Yet, some researchers may have contrary views regarding the sample size and design. For instance, Vicinanza et al.  claim that cardiac tests are sensitive and complex; hence a small sample with no inclusion of a control group is vital for comprehensive assessments. However, Wang and Ji  argue that a sufficiently large sample and inclusion of a control group are basic elements of any medical research to produce accurate and reliable findings.
In conclusion, this study aimed to identify and analyze the distribution of cardiac stem cells in the human heart. Although this study’s outcomes revealed that the atria contain a higher concentration of cardiac stem cells and serve as the main source of regeneration, the findings were limited by a small sample and the lack of a control group. The researchers established that Atria could be used to obtain HCSCs because of a high concentration of CMs. Nevertheless, the outcomes could only be generalized to older adults with cardiac infections due to the small sample. In addition, this study’s design did not incorporate a control group, hence undermining the accuracy of results due to lack of comparison in the distribution of cardiac stem cells in the heart between cardiac patients and healthy controls. Further studies with large samples and control groups are needed to confirm this study’s outcomes.
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