Coated-Platelet Levels Increase with Number of Injuries in Patients with Mild Traumatic Brain Injury

Abstract

Coated-platelets are procoagulant platelets that are elevated in stroke and are associated with stroke recurrence. In a previous study, prompted by data showing an increased risk for stroke following traumatic brain injury (TBI), we found that coated-platelet levels are elevated in patients with combat-related mild TBI (mTBI) several years after the injury, compared with controls. We now investigate in an expanded patient population whether parameters commonly recorded in mTBI are related to increased coated-platelet potential. Coated-platelet levels were assayed in 120 mTBI patients at intervals ranging from 6 months to 10 years from the last injury. Correlations were calculated between coated-platelet levels and age, gender, race/ethnicity, loss of consciousness, alteration in consciousness, post-traumatic amnesia, number of injuries, mechanism of injury, time since first and last injury, smoking, medications that may influence coated-platelet levels, and pertinent comorbid conditions. Significant correlations were detected between coated-platelet levels and number of injuries (p = 0.026), gender (p = 0.01), and time since last injury (p = 0.04). A multi-variable linear model analysis, including these three parameters and an additional three parameters (race/ethnicity, smoking, and mechanism of injury) that reached a p value of <0.2, showed that the number of injuries were predictive of coated-platelet levels (p = 0.004). These results support a mechanistic link between increased coated-platelet levels and repeated injuries in mTBI. Long-term studies will be required to determine the impact of increased prothrombotic potential in mTBI patients.

Altered Blood Biomarker Profiles in Athletes with a History of Repetitive Head Impacts

“…Furthermore, while numerous cytokines have been found elevated for up to three months after severe TBI [ 79 ], few studies have evaluated the chronic inflammatory response after concussion. Yet, Prodan and colleagues found platelet activation in previously concussed military personnel ranging from 6 months to 9 years post-injury [ 33 ], and in a follow-up study, identified a positive correlation between this inflammatory correlate and the number of concussions sustained [ 80 ]. While these previous works evaluated military personnel and included mechanistically distinct blast-related concussion, the results are consistent with our findings, and suggest that biological perturbations resulting from multiple head injuries are evident systemically up to years after injury.…”

Coagulopathy induced by traumatic brain injury: systemic manifestation of a localized injury

“…Platelets from TBI patients and those from rats and pigs subjected to experimental TBI have moderately low counts, are often activated, produce MVs, and express procoagulant activity. [55][56][57] Pulmonary and cerebral microthrombosis is also reported in animal models of TBI. 58 The cerebral microthrombi are mostly detected in the pericontusion cortex 59,60 and contain not only fibrin 61 but also platelets 58,60 and von Willebrand factor.…”

The biology of the platelet with special reference to inflammation wound healing and immunity

“…Intriguingly, such findings only apply to subsets of the total platelet population; nevertheless, an increased presence of procoagulant cells can tip the balance from hemostasis to thrombosis. PS-expressing platelets that retain procoagulant and serotonin-derived adhesive proteins are often referred to as "coated" platelets; their levels are often increased after trauma, for example after brain injury and they have been implicated in stroke (78).…”