Many studies have been done with the relationship of cytokines and the neurological worsening of stroke, but it seems there is never a final conclusion. Cytokines are shown to be released after an ischemic stroke takes place, they can either be pro or anti inflammatory markers. One study, by Nicolas Vila M.D., showed the potential benefit of the cytokine Interlukin-10. IL-10 is an anti-inflammatory marker that shows to have a correlation with stable or improving neurological damage after stroke. The patients that experience worsening symptoms have lower IL-10 levels in their plasma as compared to those who were stable or improved. This article seems like it could come to a good conclusion, until you look further into the details. Like many articles written, variables in the experiment are not fully noted and when not mentioned give a false sense of conclusion.
This study took patients plasma upon entry, but in detail this time lapse was very large. Patients plasma was taken from 80% of the patients with in 12 hours. Although 80% seems like a great number, what about 12 hours, could that potentially lead to false data from the degeneration of those cytokines. Secondly the plasma was frozen "immediately" after, for them this means there could have been a delay of up to 14 hours. These 14 hours many things could change the composition of the blood. Once they finally got the blood into the freezer it stayed there for 5-7 years. Again, change in composition is very likely in that time period.
Not only does the issue of plasma arise in this article but the main characteristics for the population studied shows significant flaws. The average age of the worsening patients was 8.5 compared to stable being 68.2. This mean age is very significant and is not at all mentioned in the actual text. Not to mention the systolic and diastolic blood pressure of worsening group was 60/1.7, obviously experiencing a lot more severe of a stroke than those with the blood pressure of 160.9/92.1 of those that remained stable. Along with this the mean temperature for those that worsened was 7.8 degrees Celsius compared to 36.8 degrees Celsius in those that were stable. Since these patients have mean numbers of a person that is in a coma or dead. So no wonder there has been no conclusion drawn about cytokines if studies like this are being produced.
04 October 2010
Cytokines in stroke
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Its too bad more rigorous quality control measures were not implemented for blood collection, processing and storage considering it was such an important component to there research.
ReplyDeleteI agree with Aubrey, it is too bad, at first glance this paper seems like it could be onto something. But it's almost too simple, basically saying high IL-10: good, and low IL-10: bad. I thought to myself okay, this makes sense IL-10 is an antiinflammatory cytokine, and having a higher presence after stroke would cause less inflamation and less damage, thus leading to better clinical neurological recovery after stroke. However when you do look more at the details of the study, i.e. Table 1, and the storage duration things start to get a little fishy. The fact that Table-1 isn't even mentioned or explained makes it a little bit more fishy. They obviously omitted these things for a reason.
ReplyDeleteAlso, it seems like they could have thought a little more about what temperature to store there plasma samples at. They had some pretty precise conditions under which they were trying to collect, so they must have thought "hey this might take a while to get all the samples we need". I feel like minus 80 degrees celsius leaves that room for error or false readings, maybe they should have stored it cryogenically at -196 celsius where almost all biological activity stops, this would lead to a longer shelf life.
I agree with Aubrey. If blood is such an important factor in this study, it should have been collected and stored in a much more timely manner. If the blood samples were stored for 5-7 years, I would think that a lot of information could have been lost over that time period.
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