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Kirkman M.A.,Brain Injury Research Group
British Journal of Neurosurgery | Year: 2011

Intracerebral haemorrhage is a devastating condition lacking effective therapies, with an uncertain role for surgery in many. Early research described an ischaemic penumbra around the haematoma, representing an area of potential therapeutic intervention. This article discusses the evidence for and against the existence of an ischaemic penumbra in ICH, with particular reference to recent imaging studies. © 2011 The Neurosurgical Foundation. Source


Boutin H.,University of Manchester | Prenant C.,University of Manchester | Maroy R.,Service Hospitalier Frederic Joliot Commissariat a lEnergie Atomique | Galea J.,University of Manchester | And 12 more authors.
PLoS ONE | Year: 2013

Purpose: Neuroinflammation is involved in several brain disorders and can be monitored through expression of the translocator protein 18 kDa (TSPO) on activated microglia. In recent years, several new PET radioligands for TSPO have been evaluated in disease models. [18F]DPA-714 is a TSPO radiotracer with great promise; however results vary between different experimental models of neuroinflammation. To further examine the potential of [18F]DPA-714, it was compared directly to [11C]PK11195 in experimental cerebral ischaemia in rats. Methods: Under anaesthesia, the middle cerebral artery of adult rats was occluded for 60 min using the filament model. Rats were allowed recovery for 5 to 7 days before one hour dynamic PET scans with [11C]PK11195 and/or [18F]DPA-714 under anaesthesia. Results: Uptake of [11C]PK11195 vs [18F]DPA-714 in the ischemic lesion was similar (core/contralateral ratio: 2.84±0.67 vs 2.28±0.34 respectively), but severity of the brain ischemia and hence ligand uptake in the lesion appeared to vary greatly between animals scanned with [11C]PK11195 or with [18F]DPA-714. To solve this issue of inter-individual variability, we performed a direct comparison of [11C]PK11195 and [18F]DPA-714 by scanning the same animals sequentially with both tracers within 24 h. In this direct comparison, the core/contralateral ratio (3.35±1.21 vs 4.66±2.50 for [11C]PK11195 vs [18F]DPA-714 respectively) showed a significantly better signal-to-noise ratio (1.6 (1.3-1.9, 95%CI) fold by linear regression) for [18F]DPA-714. Conclusions: In a clinically relevant model of neuroinflammation, uptake for both radiotracers appeared to be similar at first, but a high variability was observed in our model. Therefore, to truly compare tracers in such models, we performed scans with both tracers in the same animals. By doing so, our result demonstrated that [18F]DPA-714 displayed a higher signal-to-noise ratio than [11C]PK11195. Our results suggest that, with the longer half-life of [18F] which facilitates distribution of the tracer across PET centre, [18F]DPA-714 is a good alternative for TSPO imaging. © 2013 Boutin et al. Source


Emsley H.C.A.,Royal Preston Hospital | Hopkins S.J.,Brain Injury Research Group
Infectious Disorders - Drug Targets | Year: 2010

Infections occur commonly following stroke and adversely influence outcome. Dysphagia, greater stroke severity and increasing age are associated with post-stroke infection, but post-stroke immunodepression is now recognised as an independent factor associated with increased susceptibility. Counter-regulatory responses, triggered by the proinflammatory response to stroke, appear to effect systemic immunodepression via suppression of both innate and adaptive immune responses. Experimental and clinical studies have identified a range of anti-inflammatory and immunosuppressive changes, including reduced mononuclear phagocyte and natural killer cell function, induction of antiinflammatory cytokines, apoptotic lymphocyte loss and altered T lymphocyte activity. A range of mechanisms has been proposed, including hypothalamo-pituitary-adrenal axis (HPAA) and sympathetic nervous system (SNS) activation. The post-stroke balance of pro- and anti-inflammatory mechanisms may be aimed at restricting the extent of inflammation and contributing to the restoration of immune homeostasis. However, severe inflammation in the brain may trigger major systemic, counter-inflammatory responses that ultimately compromise immune mechanisms required to combat pathogens. Although key pathways have been identified, the extent to which the various elements of post-stroke immunodepression are clinically relevant remains to be discovered. The identification of markers of immunodepression in the early post-stroke phase may prove useful for identifying patients that may have increased susceptibility to infection. It also seems likely that post-stroke immunodepression will need to be taken into account where stroke treatments impact upon inflammatory and immune pathways. © 2010 Bentham Science Publishers Ltd. Source


Karim S.,University of Manchester | Hopkins S.,Brain Injury Research Group | Purandare N.,University of Exeter | Crowther J.,University of Liverpool | And 3 more authors.
International Journal of Geriatric Psychiatry | Year: 2014

Objective To prospectively monitor plasma inflammatory marker concentrations in peripheral blood, over 12 months, in subjects with amnestic mild cognitive impairment (MCI), and to determine the relationship between peripheral inflammatory markers and cognitive decline. Methods Seventy patients with amnestic MCI were recruited from two sites providing specialist memory assessment services in Manchester. The baseline assessment included physical examination, neuro-psychological testing and venous blood samples for C-reactive protein (CRP) and interleukin 6 (IL-6) concentrations. Sixty two participants were followed up after 12 months and the assessments were repeated. Results Data analysis revealed a significant rise in CRP, but not IL-6 concentrations over 12 months, which was not confounded by demographic variables. The neuro-psychological test scores had no association with CRP or IL-6 concentrations at baseline or 12 months follow-up. Conclusion This study adopted the unique approach of prospectively investigating peripheral inflammatory markers in a cohort with amnestic MCI. A significant rise in CRP concentrations over 12 months, but lack of significant association with cognition, provide no evidence for a relationship between systemic inflammation and cognitive decline in amnestic MCI. © 2013 The Authors. International Journal of Geriatric Psychiatry published by John Wiley & Sons, Ltd. © 2013 The Authors. International Journal of Geriatric Psychiatry published by John Wiley & Sons, Ltd. Source


Galea J.,Brain Injury Research Group | Cruickshank G.,University of Birmingham | Teeling J.L.,University of Southampton | Boche D.,University of Southampton | And 4 more authors.
Journal of Neurochemistry | Year: 2012

Delayed cerebral ischemia resulting from extracellular hemoglobin is an important determinant of outcome in subarachnoid hemorrhage. Hemoglobin is scavenged by the CD163-haptoglobin system in the circulation, but little is known about this scavenging pathway in the human CNS. The components of this system were analyzed in normal cerebrospinal fluid and after subarachnoid hemorrhage. The intrathecal presence of the CD163-haptoglobin-hemoglobin scavenging system was unequivocally demonstrated. The resting capacity of the CD163-haptoglobin-hemoglobin system in the normal CNS was 50 000-fold lower than that of the circulation. After subarachnoid hemorrhage, the intrathecal CD163-haptoglobin-hemoglobin system was saturated, as shown by the presence of extracellular hemoglobin despite detectable haptoglobin. Hemoglobin efflux from the CNS was evident, enabling rescue hemoglobin scavenging by the systemic circulation. Therefore, the CNS is not capable of dealing with significant intrathecal hemolysis. Potential therapeutic options to prevent delayed cerebral ischemia ought to concentrate on augmenting the capacity of the intrathecal CD163-haptoglobin-hemoglobin scavenging system and strategies to encourage hemoglobin efflux from the brain. This study was performed to examine the CD163-haptoglobin-hemoglobin system in the healthy human CNS and after subarachnoid hemorrhage. Compared with the circulation, the healthy human CNS has a very limited hemoglobin-scavenging capacity, which is clearly overwhelmed in subarachnoid hemorrhage. Results identify two potential therapeutic strategies to prevent delayed cerebral ischemia: inhibition of CD163 shedding and augmentation of Hb efflux from the brain. © 2011 The Authors. Source

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