A multicenter preclinical, randomized, controlled trial (pRCT) of a potential stroke treatment in mice demonstrates the feasibility of performing clinical trial–like investigations in animal models.

Traditionally seen as a sudden, brutal event with short-term impairment, traumatic brain injury (TBI) may cause persistent, sometimes life-long, consequences. While mortality after TBI has been reduced, a high proportion of severe TBI survivors require prolonged rehabilitation and may suffer long-term physical, cognitive, and psychological disorders. Additionally, chronic consequences have been identified not only after severe TBI but also in a proportion of cases previously classified as moderate or mild. This burden affects the daily life of survivors and their families; it also has relevant social and economic costs.Outcome evaluation is difficult for several reasons: co-existing extra-cranial injuries (spinal cord damage, for instance) may affect independence and quality of life outside the pure TBI effects; scales may not capture subtle, but important, changes; co-operation from patients may be impossible in the most severe cases. Several instruments have been developed for capturing specific aspects, from generic health status to specific cognitive functions. Even simple instruments, however, have demonstrated variable inter-rater agreement.The possible links between structural traumatic brain damage and functional impairment have been explored both experimentally and in the clinical setting with advanced neuro-imaging techniques. We briefly report on some fundamental findings, which may also offer potential targets for future therapies.Better understanding of damage mechanisms and new approaches to neuroprotection-restoration may offer better outcomes for the millions of survivors of TBI.

Objectives-To assess the frequency of hyperthermia in a population of acute neurosurgical patients; to assess the relation between brain temperature (ICT) and core temperature (Tc); to investigate the eVect of changes in brain temperature on intracranial pressure (ICP). Methods-The study involved 20 patients (10 severe head injury, eight subarachnoid haemorrhage, two neoplasms) with median Glasgow coma score (GCS) 6. ICP and ICT were monitored by an intraventricular catheter coupled with a thermistor. Internal Tc was measured in the pulmonary artery by a Swan-Ganz catheter. Conclusions-Fever is extremely frequent during acute cerebral damage and ICT is significantly higher than Tc. Moreover, Tc may underestimate ICT during the phases when temperature has the most impact on the intracranial system because of the close association between increases in ICT and ICP. (J Neurol Neurosurg Psychiatry 2001;71:448-454) Results-Mean

Cells of myeloid origin, such as microglia and macrophages, act at the crossroads of several inflammatory mechanisms during pathophysiology. Besides pro-inflammatory activity (M1 polarization), myeloid cells acquire protective functions (M2) and participate in the neuroprotective innate mechanisms after brain injury. Experimental research is making considerable efforts to understand the rules that regulate the balance between toxic and protective brain innate immunity. Environmental changes affect microglia/macrophage functions. Hypoxia can affect myeloid cell distribution, activity, and phenotype. With their intrinsic differences, microglia and macrophages respond differently to hypoxia, the former depending on ATP to activate and the latter switching to anaerobic metabolism and adapting to hypoxia. Myeloid cell functions include homeostasis control, damage-sensing activity, chemotaxis, and phagocytosis, all distinctive features of these cells. Specific markers and morphologies enable to recognize each functional state. To ensure homeostasis and activate when needed, microglia/macrophage physiology is finely tuned. Microglia are controlled by several neuron-derived components, including contact-dependent inhibitory signals and soluble molecules. Changes in this control can cause chronic activation or priming with specific functional consequences. Strategies, such as stem cell treatment, may enhance microglia protective polarization. This review presents data from the literature that has greatly advanced our understanding of myeloid cell action in brain injury. We discuss the selective responses of microglia and macrophages to hypoxia after stroke and review relevant markers with the aim of defining the different subpopulations of myeloid cells that are recruited to the injured site. We also cover the functional consequences of chronically active microglia and review pivotal works on microglia regulation that offer new therapeutic possibilities for acute brain injury.

The immune response after brain injury is highly complex and involves both local and systemic events at the cellular and molecular level. It is associated to a dramatic over-activation of enzyme systems, the expression of proinflammatory genes and the activation/recruitment of immune cells. The complement system represents a powerful component of the innate immunity and is highly involved in the inflammatory response. Complement components are synthesized predominantly by the liver and circulate in the bloodstream primed for activation. Moreover, brain cells can produce complement proteins and receptors. After acute brain injury, the rapid and uncontrolled activation of the complement leads to massive release of inflammatory anaphylatoxins, recruitment of cells to the injury site, phagocytosis and induction of blood brain barrier (BBB) damage. Brain endothelial cells are particularly susceptible to complement-mediated effects, since they are exposed to both circulating and locally synthesized complement proteins. Conversely, during neurodegenerative disorders, complement factors play distinct roles depending on the stage and degree of neuropathology. In addition to the deleterious role of the complement, increasing evidence suggest that it may also play a role in normal nervous system development (wiring the brain) and adulthood (either maintaining brain homeostasis or supporting regeneration after brain injury). This article represents a compendium of the current knowledge on the complement role in the brain, prompting a novel view that complement activation can result in either protective or detrimental effects in brain conditions that depend exquisitely on the nature, the timing and the degree of the stimuli that induce its activation. A deeper understanding of the acute, subacute and chronic consequences of complement activation is needed and may lead to new therapeutic strategies, including the ability of targeting selective step in the complement cascade.