Platelet secretory products may contribute to neuronal injury.
BACKGROUND
We do not fully understand the mechanisms for neuronal damage following cerebral arterial occlusion by a thrombus that consists mainly of platelets. The view that certain endogenous substances, such as glutamate, may also contribute to neuronal injury is now reasonably well established. Blood platelets are known to contain and secrete a number of substances that have been associated with neuronal dysfunction. Therefore, we hypothesize that a high concentration (approximately several thousand-fold higher than in plasma, in our estimation) of locally released platelet secretory products derived from the causative thrombus may contribute to neuronal injury and promote reactive gliosis.


RESULTS
We have recently been able to report some direct support for this concept. When organotypic spinal cord cultures were exposed to platelet and platelet products, a significant reduction in the number and the size of the surviving neurons occurred in comparison with those in controls. We further observed that serotonin, a major platelet product, has neurotoxic properties. There may be other platelet components with similar effect.


CONCLUSIONS
The hypothesis of platelet-mediated neurotoxicity gains some support from these recent in vitro findings. The concept could provide a new area of research in stroke, both at the clinical and basic levels.
Joseph
R
R
Department of Neurology, Henry Ford Hospital and Health Sciences Center, Detroit, MI 48202.
Tsering
C
C
Grunfeld
S
S
Welch
K M
KM
D000818:Animals; D001792:Blood Platelets / Q000378:metabolism*; D002545:Brain Ischemia / Q000097:blood / Q000150:complications; D002561:Cerebrovascular Disorders / Q000150:complications; D005911:Gliosis / Q000209:etiology; D005971:Glutamates / Q000378:metabolism / Q000502:physiology; D018698:Glutamic Acid; D006801:Humans; D009422:Nervous System Diseases / Q000209:etiology / Q000503:physiopathology; D009474:Neurons / Q000473:pathology / Q000502:physiology*; D010974:Platelet Aggregation; D011697:Purpura, Thrombotic Thrombocytopenic / Q000150:complications; D012701:Serotonin / Q000378:metabolism / Q000502:physiology
D005971:Glutamates; D012701:Serotonin; D018698:Glutamic Acid