We were delighted to read high-quality research article by Martino et al. [1], which entitled "Attitude and knowledge of medical students toward donation after circulatory death". Martino et al. aimed to investigate and analyze the acceptance of organ donation in Brazil. They conducted a survey of medical students in a public university in Brazil through a questionnaire containing 26 goals and Likert scale questions. The results showed that most people knew the concept of brain death, the acceptance of postmortem donation is much higher than living donation. These new findings and valuable results greatly attracted our interest, but after our reading and investigation, we found that the conclusions of Martino et al. deserve further exploration and research. We are more than happy to contribute to the debate and look forward to hearing from the authors.

First of all, the author did not conduct a multi-center survey. The author's sample only included medical students from a public university in Brazil. The sample came from a single source, but it was deduced to the whole of Brazil through the conclusion of a single center. It did not follow the multi-center principle. A single sample Sources can greatly reduce the reliability of conclusions [2,3]. Because many potential confounding factors can influence medical students' perceptions of organ donation, whether living or post-mortem. These confounding factors may include geographic environment, household income, cultural environment, regional policies, etc [4-6]. And these factors may also affect each other. In addition, there may be differences in the educational level of different universities, and the cognition of students who attend may be quite different. Students in high-level universities may be more accepting of organ donation, while students in low-level universities may be relatively low [7]. Therefore, we recommend that the authors supplement multicenter survey studies to enrich the reliability of the data.

Second, we found that the authors compared the willingness of Chinese students to donate their kidneys to relatives in vivo with that of Brazilian medical students. In fact, the comparability between the two is relatively low, because China is deeply influenced by Confucianism and culture [8]. Under the dual influence of family ethics and humanistic thought, it is not surprising that Chinese students are more willing to donate organs to their relatives. Additionally, we note that the authors mention the proportion of liver donation. The liver only needs 30% to fully regenerate [9], so people with a medical education are more willing to accept liver donations, either in vivo or posthumously.

Finally, we note that the author mentions that "Eastern countries have difficulty accepting deceased donations, while western countries have difficulty continuing with living donations". In fact, in eastern countries, especially in countries such as China and Japan, which are heavily influenced by Confucianism, living donations are often more unacceptable than post-mortem donations, because Confucian culture emphasizes“My body, including hair and skin, which given by parents, shouldn't be damaged. This is the basic of filial piety.” Filial piety is very important in these countries [10]. Gill pointed out that what really hinders organ donation in western countries are socioeconomic factors, not other factors such as religious beliefs [11].

Acknowledgments
We thank the reviewers for their comments that helped to improve the manuscript.

Conflict of Interest
Each author has reviewed the statement by the Journal of Clinical Case Reports, Medical Images and Health Sciences on conflicts of interest, and every author stated that they have no commercial, professional, or personal conflict of interest relevant to the study, and we hereby declare that we comply with the principles of publishing ethics.

Author’s contribution
Juan Zhang, Han LiandChenchen Pan conceptualization, writing of the original draft, formal analysis. Zhipeng Li reviewing, and editing. All authors participated in drafting the manuscript and all have read, contributed to, and approved the final version of the manuscript.

Data Availability
The datasets generated and analyzed in the current study are available from the corresponding author upon reasonable request.

Consent for Publication
All other authors have read the manuscript and have agreed to submit it in its current form for consideration for publication in the Journal of Clinical Case Reports, Medical Images and Health Sciences.