Impaired Cognitive Performance in Endothelial Nitric Oxide Synthase Knockout Mice After Ischemic Stroke: A Pilot Study.
Shanshan Li, Yao Wang, Ze Jiang and 6 others
PMID 29406402WHAT IT FOUND
After experimental stroke in mice, eNOS-deficient mice that could swim learned the water maze more slowly and remembered the platform location less well.
Many eNOS-deficient stroke mice could not perform the test because of movement problems.
Key findings
01Eight of 14 eNOS-deficient mice with stroke failed to perform the Morris water maze, while one wild-type mouse with stroke was a non-performer.
02Among eNOS-deficient mice that could swim, stroke caused longer platform finding on trial days 4 and 5 and less target quadrant time than sham surgery.
03There was no significant difference between wild-type and eNOS-deficient mice after stroke in survival or in global neurological score over time.
STILL TO COME
How it was doneWhat they found
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What it does not show
This was a pilot study in mice, not in people. Many eNOS-deficient stroke mice could not perform the water maze because they showed uncoordinated movement or floating, so the cognitive findings apply only to the subset that could swim. The global neurological score did not detect genotype differences, and the authors note it is subjective and may miss small deficits. The authors could not measure infarct size at 28 days because the lesion area was hard to identify. Survival did not differ significantly, but mortality was reported as about two-fold higher in eNOS-deficient stroke mice, a difference that did not reach significance.
Declared interests
The authors declared no conflicts of interest. The paper is listed as NIH and non-U.S. government funded.
The easy way to misread this
Do not conclude that eNOS deficiency causes human post-stroke cognitive impairment or that restoring eNOS would improve cognition. This was a small pilot in mice, many eNOS-deficient stroke mice could not perform the cognitive test because of motor problems, and no human therapy was tested.