This process in the lungs results in about 50% of all platelet production, which makes the lungs a main site of mature platelet production. Using mice models, the authors were able to discover high megakaryocyte concentration with low platelet concentration in blood coming into the lungs and higher platelet counts and lower megakaryocyte concentrations in blood leaving the lungs.
Investigators determined that megakaryocytes release more than 10 million platelets per hour, based on total lung volume. The amount of platelets produced by the lungs is also plastic, as was shown when researchers used the megakaryocyte growth factor thrombopoietin (TPO) in which they afterwards observed a 3x increase in platelet production and a 2x increase in megakaryocyte production of proplatelets. Proplatelets are the parts of megakaryocytes that give rise to platelets.
The results of this study can be applied to improve treatments for thrombocytopenia (low platelet count), which affects millions of patients and can aggravate pre-existing maladies. Haematopoietic stem cell (HSC) deficiencies can also be addressed. Additionally, the study can provide valuable information to the field of lung transplantation since investigators did do some mice lung transplants to show that mice with thrombocytopenia were able to bring up their platelet counts after healthy lungs were transplanted into them.
Beneficence is one of the main ethical principles that can be tied to this study since the results will be used to help millions of patients with thrombocytopenia and potentially other platelet-related ailments. However, the potential risks of treatments designed using the information from this study will need to be established before a complete analysis regarding beneficence can be made.
Journal Article:
Lefrançais, E., Ortiz-Muñoz, G., et al. The lung is a site of platelet biogenesis and a reservoir for haematopoietic progenitors. Nature 544, 105-109 (2017). doi: 10.1038/nature21706
https://www.ncbi.nlm.nih.gov/pubmed/28329764
Additional references:
https://www.webmd.com/a-to-z-guides/thrombocytopenia-symptoms-causes-treatments#1-1
This article is interesting because it shows that there is still so much we do not know about organ function and how integrative organ function can be. Looking at the methods of the journal article, the researchers were able to quantify platelet count using circulating platelets. The researchers also removed the lungs, bone marrow, and spleen to examine hematopoietic properties of these organs. Because these are invasive methods, how do you see this study being utilized in a human population to determine in human lungs also possess the same platelet biogenesis that was observed in the mouse lungs? Would observing the circulating platelet numbers in people lead to the same conclusions that were found in mice?
ReplyDeleteYou mentioned that potential risks of treatment need to evaluated before utilizing the results of the study, and I agree that risks need to be determined and that more research needs to be done on how this study can transition to a human population in the first place.
Thank you for your comment and great questions! I believe, but I’m not entirely sure, that we could determine a way that is less invasive to attempt confirmation of pulmonary platelet biogenesis. I know that we could probably acquire lung biopsies to test for levels of megakaryocytes and other haematopoietic factors. The issue here would be who the participants would be and if it is ethical to do this on healthy people or if it should be limited to patients that might be in a coma or brain dead or those about to be taken off of life-support (not saying that these patients don’t have rights as well, just that these might be more acceptable to get granted permission from the appropriate medical and ethical institutions). The safest way would be to design a therapy that uses this new information and starts treating patients mentioned in the article, but only if the possible negative side effects are minimal. I would think that similar conclusions could be drawn, yes. However, there is always potential for discovering that mice and human respiratory systems might turn out to be different in some way that might affect those conclusions. We probably won’t know until more studies are done, if they are able to.
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