BackgroundInterleukin-1 (IL-1) is a key mediator of ischaemic brain injury induced by stroke and subarachnoid haemorrhage (SAH). IL-1 receptor antagonist (IL-1Ra) limits brain injury in experimental stroke and reduces plasma inflammatory mediators associated with poor outcome in ischaemic stroke patients. Intravenous (IV) IL-1Ra crosses the blood–brain barrier (BBB) in patients with SAH, to achieve cerebrospinal fluid (CSF) concentrations that are neuroprotective in rats.MethodsA small phase II, double-blind, randomised controlled study was carried out across two UK neurosurgical centres with the aim of recruiting 32 patients. Adult patients with aneurysmal SAH, requiring external ventricular drainage (EVD) within 72 hours of ictus, were eligible. Patients were randomised to receive IL-1Ra (500 mg bolus, then a 10 mg/kg/hr infusion for 24 hours) or placebo. Serial samples of CSF and plasma were taken and analysed for inflammatory mediators, with change in CSF IL-6 between 6 and 24 hours as the primary outcome measure.ResultsSix patients received IL-1Ra and seven received placebo. Concentrations of IL-6 in CSF and plasma were reduced by one standard deviation in the IL-1Ra group compared to the placebo group, between 6 and 24 hours, as predicted by the power calculation. This did not reach statistical significance (P = 0.08 and P = 0.06, respectively), since recruitment did not reach the target figure of 32. No adverse or serious adverse events reported were attributable to IL-1Ra.ConclusionsIL-1Ra appears safe in SAH patients. The concentration of IL-6 was lowered to the degree expected, in both CSF and plasma for patients treated with IL-1Ra.
Highlights► Risk factors for stroke include atherosclerosis, obesity, diabetes and hypertension. ► Stroke risk factors are associated with peripheral inflammation. ► Corpulent rats and atherogenic mice show increased inflammation in the brain. ► Pilot data show that patients at risk of stroke may also develop brain inflammation. ► Chronic peripheral inflammation can drive inflammatory changes in the brain.
F o r S t r o k Background and PurposeThe pro-inflammatory cytokine interleukin-1 (IL-1) has a deleterious role in cerebral ischemia, which is attenuated by IL-1 receptor antagonist (IL-1Ra). IL-1 induces peripheral inflammatory mediators, such as interleukin-6 (IL-6), which are associated with worse prognosis after ischemic stroke. We investigated whether subcutaneous (SC) IL-1Ra reduces the peripheral inflammatory response in acute ischemic stroke. MethodsSCIL-STROKE was a single-center, double-blind, randomized, placebo-controlled phase 2 trial of SC IL-1Ra (100mg administered twice daily for three days) in patients presenting within 5h of ischemic stroke onset. Randomization was stratified for baseline NIHSS score and thrombolysis. Measurement of plasma IL-6 and other peripheral inflammatory markers was undertaken at five time points. The primary outcome was difference in concentration of log(IL-6) as area under the curve to Day 3. Secondary outcomes included exploratory effect of IL-1Ra on three month outcome with the modified Rankin Scale (mRS). ResultsWe recruited 80 patients (mean age 72, median NIHSS 12) of whom 73% received intravenous thrombolysis with alteplase. IL-1Ra significantly reduced plasma and plasma C-reactive protein (p<0.001). IL-1Ra was well-tolerated with no safety concerns.Allocation to IL-1Ra was not associated with a favorable outcome on mRS: OR (95% CI) = 0.67 (0.29 to 1.52); p=0.34. Exploratory mediation analysis suggested that IL-1Ra improved clinical outcome by reducing inflammation, but there was a statistically significant, alternative mechanism countering this benefit. ConclusionsIL-1Ra reduced plasma inflammatory markers which are known to be associated with worse clinical outcome in ischemic stroke. SC IL-1Ra is safe and well-tolerated. Further 3
BackgroundInflammation is hypothesized to be a key event in the growth of sporadic vestibular schwannoma (VS). In this study we sought to investigate the relationship between inflammation and tumor growth in vivo using the PET tracer 11C-(R)-PK11195 and dynamic contrast enhanced (DCE) MRI derived vascular biomarkers.MethodsNineteen patients with sporadic VS (8 static, 7 growing, and 4 shrinking tumors) underwent prospective imaging with dynamic 11C-(R)-PK11195 PET and a comprehensive MR protocol, including high temporal resolution DCE-MRI in 15 patients. An intertumor comparison of 11C-(R)-PK11195 binding potential (BPND) and DCE-MRI derived vascular biomarkers (Ktrans, vp, ve) across the 3 different tumor growth cohorts was undertaken. Tissue of 8 tumors was examined with immunohistochemistry markers for inflammation (Iba1), neoplastic cells (S-100 protein), vessels (CD31), the PK11195 target translocator protein (TSPO), fibrinogen for vascular permeability, and proliferation (Ki-67). Results were correlated with PET and DCE-MRI data.ResultsCompared with static tumors, growing VS displayed significantly higher mean 11C-(R)-PK11195 BPND (−0.07 vs 0.47, P = 0.020), and higher mean tumor Ktrans (0.06 vs 0.14, P = 0.004). Immunohistochemistry confirmed the imaging findings and demonstrated that TSPO is predominantly expressed in macrophages. Within growing VS, macrophages rather than tumor cells accounted for the majority of proliferating cells.ConclusionWe present the first in vivo imaging evidence of increased inflammation within growing sporadic VS. Our results demonstrate that 11C-(R)-PK11195 specific binding and DCE-MRI derived parameters can be used as imaging biomarkers of inflammation and vascular permeability in this tumor group.
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