Figure 1. Post-traumatic brain contusions may increase in size and cause edema with consequent neurologic deterioration. Adequate knowledge of these mechanisms may improve final outcome. Traumatic brain injury (TBI) is the number 1 cause of death in trauma victims who reach the hospital alive. TBI is a complex, multifaceted disease. Among this population, intracerebral hemorrhage, or “brain contusion,” is a common finding. One of the most important and least studied is the serious problem of spatiotemporal progression of brain contusions. Also called posttraumatic brain contusions (PTBCs), these contusions are traditionally considered primary injuries, but they have an inherent capacity to increase in size, generate perilesional edema, cause mass effect, induce neurologic deterioration, and, in some patients, cause death (Figure 1). These lesions are frequently associated with volumetric expansion during the first 48 hours post trauma. In most patients, there is a progressive increase in pericontusional edema, and in nearly half of patients, there is an increase in the hemorrhagic component itself. Until recently, the underlying molecular pathophysiology of contusion-induced brain edema and hemorrhagic progression was poorly understood. However, new evidence has accumulated in the past decade and the complex cellular and molecular mechanisms underlying PTBCs volumetric increases have been better predictable. Since the works of Simard et al., in which newly expressed SUR1-regulated NC (Ca-ATP) channel mediates cerebral edema after ischemic stroke, more attention has been given to this protein and its blockade in brain injuries, especially traumatic brain lesions. The same author, in another study, induced focal cortical contusions in rats and the regulatory subunit of the channel, SUR1, was prominently upregulated in capillaries of penumbral tissues surrounding the contusion. Corroborating the previous findings, Martinez-Valverde et al. reported SUR1 expression in humans with PTBCs. They found that SUR1 was significantly upregulated in all types of brain cells with especially prominent increases in neurons, glia, and endothelial cells. Therapeutic management of PTBCs has been limited to date. The fact that SUR1 is upregulated in these lesions opens new opportunities (e.g., glyburide) to modulate the molecular cascades generated by these focal injuries.
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