Nicotinamide Deteriorates Post-Stroke Immunodepression Following Cerebral Ischemia-Reperfusion Injury in Mice.

(1) Background: Inducing experimental stroke leads to biphasic immune responses, where the early activation of immune functions is followed by severe immunosuppression accompanied by spleen and thymus atrophy. Nicotinamide, a water-soluble B-group vitamin, is a known neuroprotectant against brain ischemia in animal models. We examined the effect of nicotinamide on the central and peripheral immune response in experimental stroke models. (2) Methods: Nicotinamide (500 mg/kg) or saline was intravenously administered to C57BL/6 mice during reperfusion after transiently occluding the middle cerebral artery or after LPS injection. On day 3, the animals were examined for behavioral performance and were then sacrificed to assess brain infarction, blood-brain barrier (BBB) integrity, and the composition of immune cells in the brain, thymus, spleen, and blood using flow cytometry. (3) Results: Nicotinamide reduced brain infarction and microglia/macrophage activation following MCAo (p < 0.05). Similarly, in LPS-injected mice, microglia/macrophage activation was decreased upon treatment with nicotinamide (p < 0.05), suggesting a direct inhibitory effect of nicotinamide on microglia/macrophage activation. Nicotinamide decreased the infiltration of neutrophils into the brain parenchyma and ameliorated Evans blue leakage (p < 0.05), suggesting that a decreased infiltration of neutrophils could, at least partially, be the result of a more integrated BBB structure following nicotinamide treatment. Our studies also revealed that administering nicotinamide led to retarded B-cell maturation in the spleen and subsequently decreased circulating B cells in the thymus and bloodstream (p < 0.05). (4) Conclusions: Cumulatively, nicotinamide decreased brain inflammation caused by ischemia-reperfusion injury, which was mediated by a direct anti-inflammatory effect of nicotinamide and an indirect protective effect on BBB integrity. Administering nicotinamide following brain ischemia resulted in a decrease in circulating B cells. This warrants attention with respect to future clinical applications.

Use of magnetic fields and nitrate concentration to optimize the growth and lipid yield of Nannochloropsis oculata.

Microalgae produce increased lipid content accompanied by a significant decrease in cell density with decreasing nitrate concentration. Magnetic fields (MF) have been reported as a factor that could accelerate metabolism and growth in microalgae culture. Thus, this study aimed to optimize the influence of MF and nitrate concentration (sodium nitrate, N) on the growth and lipid productivity of Nannochloropsis oculata. A single-factor experiment integrated with response surface methodology (RSM) via central composite design (CCD) was performed. The results showed that the maximum specific growth rate (0.24 d-1) and maximum lipid productivity (38 mg L-1 d-1) obtained in this study were higher than those of the control culture (by 166% and 103%, respectively). This study also found that the two-way interaction term MF × N had a significant effect on cell growth but not on lipid production. It was concluded that to design appropriate MF for enhanced lipid productivity due to cell growth, further research must focus on developing an understanding of the relationship between the bioeffects of the magnetic field and the proteomic changes involved in lipid accumulation strategies. This approach would enable the design of conditions to obtain inexpensive high-value products from N. oculata.

Successful Modified Transoral Endoscopic Parathyroidectomy Vestibular Approach For Secondary Hyperparathyroidism With Ectopic Mediastinal Glands.

BACKGROUND: Transoral endoscopic parathyroidectomy vestibular approach for secondary hyperparathyroidism (SHPT) is controversial with regard to the time consumed, safety, and feasibility. We present our initial experience with modified transoral endoscopic parathyroidectomy vestibular approach (m-TOEPVA) procedure for SHPT using total parathyroidectomy with autotransplantation. MATERIALS AND METHODS: We retrospectively reviewed 10 patients with SHPT who underwent the m-TOEPVA procedure from December 2017 to April 2018 at our center. RESULTS: There were a total of 6 male individuals and 4 female individuals with a median age of 58.5 years. Among whom, 5 were on hemodialysis and 5 on peritoneal dialysis. The median length of hospital stay and operative time was 5 (4, 5) days, and 321.5 (302.75, 362.25) minutes, respectively. Successful removal of 4 parathyroid glands was achieved in 8 of 10 patients (80%) and, in 8 patients (8/10, 80%), the intact parathyroid hormone successfully dropped to <300 pg/mL at 3 months postoperatively. Two patients with ectopic parathyroid gland in the superior mediastinum were noted preoperatively by MIBI scan and subsequently had successful removal. Except for 1 patient with prolonged hospital stay (11 d) due to hungry bone syndrome, there were no other major complications. CONCLUSION: m-TOEPVA by total parathyroidectomy with autotransplantation for SHPT is feasible, safe, and offers optimal cosmetic results. The most valuable part is that m-TOEPVA provides direct visualization and successful removal of the ectopic parathyroid glands in the superior mediastinum.

Prediction of the Development of Persistent Massive Ascites After Living Donor Liver Transplantation Using a Perioperative Risk Score.

BACKGROUND: Persistent massive ascites (PMAS) longer than 14 days after living donor liver transplantation is not uncommon and associated with worse outcome. A predictive risk scoring system was constructed after analysis of recipient, graft, and surgery-related factors. METHODS: We retrospectively reviewed adult living donor liver transplantation recipients from 2005 to 2011 after excluding cases that experienced any intervention for perioperative vascular-related events. Two groups were identified, PMAS and non-PMAS. The score was constructed from significant factors using weighted odds ratios (OR). RESULTS: The study population included 439 recipients. Persistent massive ascites was evident in 74 cases (17%). Five significant risk predictors were identified in multivariate analysis: pretransplant serum creatinine greater than 1.5 mg/dL (OR, 5.693; weighted OR, 2), recipient spleen to graft volume ratio greater than 1.3 (OR, 4.466; weighted OR, 2), left lobe graft (OR, 3.196; weighted OR, 1), more than 1000 mL ascites at laparotomy (OR, 2.541; weighted OR, 1), and graft recipient weight ratio less than 0.8 (OR, 2.419; weighted OR, 1). The clinical scoring system was constructed and ranged from 0 to 7. Receiver operating characteristic analysis showed an area under the curve (0.778, P < 0.001). Internal validation of the score showed an area under the curve of 0.783. The 5- and 10-year survival rates for the non-PMAS versus the PMAS groups were 89% and 84% versus 81% and 48%, respectively (P = 0.001). CONCLUSIONS: The PMAS score is a predictive pretransplant clinical tool. A Clinical cutoff score of 4 might be decision-changing. Pretransplant correction of renal functions, deciding to harvest a large graft and/or consideration of splenic artery embolization could reduce the risk of PMAS.

Management and climate contributions to satellite-derived active fire trends in the contiguous United States.

Fires in croplands, plantations, and rangelands contribute significantly to fire emissions in the United States, yet are often overshadowed by wildland fires in efforts to develop inventories or estimate responses to climate change. Here we quantified decadal trends, interannual variability, and seasonality of Terra Moderate Resolution Imaging Spectroradiometer (MODIS) observations of active fires (thermal anomalies) as a function of management type in the contiguous U.S. during 2001-2010. We used the Monitoring Trends in Burn Severity database to identify active fires within the perimeter of large wildland fires and land cover maps to identify active fires in croplands. A third class of fires defined as prescribed/other included all residual satellite active fire detections. Large wildland fires were the most variable of all three fire types and had no significant annual trend in the contiguous U.S. during 2001-2010. Active fires in croplands, in contrast, increased at a rate of 3.4% per year. Cropland and prescribed/other fire types combined were responsible for 77% of the total active fire detections within the U.S and were most abundant in the south and southeast. In the west, cropland active fires decreased at a rate of 5.9% per year, likely in response to intensive air quality policies. Potential evaporation was a dominant regulator of the interannual variability of large wildland fires, but had a weaker influence on the other two fire types. Our analysis suggests it may be possible to modify landscape fire emissions within the U.S. by influencing the way fires are used in managed ecosystems. KEY POINTS: Wildland, cropland, and prescribed fires had different trends and patternsSensitivity to climate varied with fire typeIntensity of air quality regulation influenced cropland burning trends.

Evaluating greenhouse gas emissions inventories for agricultural burning using satellite observations of active fires.

Fires in agricultural ecosystems emit greenhouse gases and aerosols that influence climate on multiple spatial and temporal scales. Annex 1 countries of the United Nations Framework Convention on Climate Change (UNFCCC), many of which ratified the Kyoto Protocol, are required to report emissions of CH4 and N2O from these fires annually. In this study, we evaluated several aspects of this reporting system, including the optimality of the crops targeted by the UNFCCC globally and within Annex 1 countries, and the consistency of emissions inventories among different countries. We also evaluated the success of individual countries in capturing interannual variability and long-term trends in agricultural fire activity. In our approach, we combined global high-resolution maps of crop harvest area and production, derived from satellite maps and ground-based census data, with Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) measurements of active fires. At a global scale, we found that adding ground nuts (e.g., peanuts), cocoa, cotton and oil palm, and removing potato, oats, rye, and pulse other from the list of 14 crops targeted by the UNFCCC increased the percentage of active fires covered by the reporting system by 9%. Optimization led to a different recommended list for Annex 1 countries, requiring the addition of sunflower, cotton, rapeseed, and alfalfa and the removal of beans, sugarcane, pulse others, and tuber-root others. Extending emissions reporting to all Annex 1 countries (from the current set of 19 countries) would increase the efficacy of the reporting system from 6% to 15%, and further including several non-Annex 1 countries (Argentina, Brazil, China, India, Indonesia, Thailand, Kazakhstan, Mexico, and Nigeria) would capture over 55% of active fires in croplands worldwide. Analyses of interannual trends from the United States and Australia showed the importance of both intensity of fire use and crop production in controlling year-to-year variations in agricultural fire emissions. Remote sensing provides an effective means for evaluating some aspects of the current UNFCCC emissions reporting system; and, if combined with census data, field experiments and expert opinion, has the potential to improve the robustness of the next generation inventory system.

Optimal Percoll concentration facilitates flow cytometric analysis for annexin V/propidium iodine-stained ischemic brain tissues.

We sought to determine the optimal Percoll concentration for ischemic rat brain prepared for flow cytometric (FC) measurements. Animals were subjected to the right middle cerebral artery (MCA) occlusion, and were euthanized at 3, 12, 24, and 72 h after reperfusion onset. The brains were processed by different concentrations (unisolated, 20, 25, 30, or 40%) of Percoll and stained with annexin V/propidium iodine (PI). Ischemic brain damage was evaluated by FC analysis and image analysis for histologic sections. The relative susceptibility of different phenotypes of cells to necrotic and apoptotic damage were evaluated by the FC analyses for the immunohistochemistry, PI, and the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL)-processed brain tissues. Our results showed that FC analysis effectively detected the extent and maturation of apoptotic/necrotic brain damage, and the results were consistent with those determined from histologic brain sections. Neuron was more vulnerable to apoptosis than glia, whereas both cellular phenotypes were compatible in susceptibility for necrotic cell death. Percoll at a low concentration (20%) could effectively remove tissue debris without affecting membranous integrity of the injured neurons. Conversely, high percentages of Percoll (30-40%) substantially increased membranous damage for the injured cells. These results supported the application of FC to determine the extent and progression in time, as well as relative phenotypes of apoptotic/necrotic cell deaths following ischemic damage. We highlighted the use of Percoll at low percentages to facilitate the removal of tissue debris and to improve membrane integrity preservation for the injured neurons.

Nicotinamide inhibits nuclear factor-kappa B translocation after transient focal cerebral ischemia.

OBJECTIVE: We explored the putative anti-inflammatory effects of nicotinamide against experimental stroke. DESIGN: Prospective laboratory study. SETTING: Research laboratory in a university teaching hospital. SUBJECTS: Adult male Sprague-Dawley rats (250-300 g). INTERVENTIONS: The antioxidant, radical scavenging, and anti-inflammatory actions of nicotinamide were evaluated using a panel of acellular assays and lipopolysaccharide-stimulated RAW 264.7 and BV2 cells. Animals were subjected to transient middle cerebral artery occlusion for 90 mins. Nicotinamide (500 mg/kg) or vehicle was given intravenously at reperfusion onset. MEASUREMENTS AND MAIN RESULTS: Nicotinamide effectively inhibited nuclear factor-κB translocation and binding activity as well as the production of tumor necrosis factor-α, nitrite/nitrate, and interleukin-6 in the lipopolysaccharide-stimulated RAW 264.7 and BV2 cells (p < .05, respectively) but exhibited weak antioxidant and radical-scavenging actions. Relative to controls, nicotinamide-treated animals had significant reductions in neutrophil and macrophage/activated microglial infiltration in the ischemic brain by 53% and 77% (p < .05, respectively). Additionally, nicotinamide significantly attenuated phosphorylation of nuclear factor-κB's inhibitory protein, nuclear factor-κB translocation and binding activity, and the synthesis of inducible nitric oxide in the ischemic brain (p < .05, respectively). Consequently, nicotinamide effectively reduced brain infarction and improved neurobehavioral outcome by 43% and 50% (p < .05, respectively). CONCLUSIONS: Nicotinamide effectively attenuated postischemic nuclear factor-kappa]B activation and exhibited robust anti-inflammatory actions against ischemic stroke.

Melatonin inhibits postischemic matrix metalloproteinase-9 (MMP-9) activation via dual modulation of plasminogen/plasmin system and endogenous MMP inhibitor in mice subjected to transient focal cerebral ischemia.

We have shown that melatonin attenuated matrix metalloproteinase-9 (MMP-9) activation and decreased the risk of hemorrhagic transformation following cerebral ischemia-reperfusion. Herein, we investigate the possible involvement of the plasminogen/plasmin system and endogenous MMPs inhibitor underlying the melatonin-mediated MMP-9 inhibition. Mice were subjected to 1-hr ischemia and 48-hr reperfusion of the right middle cerebral artery. Melatonin (5 mg/kg) or vehicle was intravenously injected upon reperfusion. Brain infarction and hemorrhagic transformation were measured. Extracellular matrix damage was determined by Western immunoblot analysis for laminin protein. The activity and expression of MMP-2 and MMP-9 were determined by gelatin zymography, in situ zymography, and Western immunoblot analysis. In addition, the activities of tissue and urokinase plasminogen activators (tPA and uPA) were evaluated by plasminogen-dependent casein zymography. Endogenous plasminogen activator inhibitor (PAI) and tissue inhibitors of MMP (TIMP-1) were investigated using enzyme-linked immunosorbent assay (ELISA) and Western immunoblot analysis, respectively. Cerebral ischemia-reperfusion induced increased MMP-9 activity and expression at 12-48 hr after reperfusion onset. Relative to controls, melatonin-treated animals had significantly decreased MMP-9 activity and expression (P<0.05), in addition to reduced brain infarction and hemorrhagic transformation as well as improved laminin protein preservation. This melatonin-mediated MMP-9 inhibition was accompanied by reduced uPA activity (P<0.05), as well as increased TIMP-1 expression and PAI activity (P<0.05, respectively). These results demonstrate the melatonin's pluripotent mechanisms for attenuating postischemic MMP-9 activation and neurovascular damage, and further support it as an add-on to thrombolytic therapy for ischemic stroke patients.

Early reperfusion improves the recovery of contralateral electrophysiological diaschisis following focal cerebral ischemia in rats.

OBJECTIVES: We evaluated electrophysiological benefits of reperfusion following ischemic stroke. METHODS: Rats received either transient proximal occlusion of the right middle cerebral artery for 30 (Group I, n=8) or 90 minutes (Group II, n=8) or permanent thermocoagulation of the distal right middle cerebral artery (Group III, n=6). Neurobehavioral outcome and somatosensory evoked potentials (SSEPs) were examined before and at 7 days after the onset of brain ischemia. Brain infarction was assessed after the rats were euthanized. RESULTS: Before ischemia, stable SSEPs were consistently recorded. At 7 days post-insult, Group III (permanent occlusion) had the greatest reduction in the SSEPs recorded ipsilaterally and contralaterally. Groups I and II (transient ischemic groups) also had depressant SSEPs recorded from the ipsilateral ischemic and the contralateral intact brain (electrophysiological diaschisis). However, prolonged ischemia resulted in greater brain infarction and increased neurological deficits in addition to greater reductions in the ipsilateral and the contralateral SSEPs. CONCLUSION: Early reperfusion facilitates the electrophysiological recovery in both ipsilateral lesional and the contralateral intact brain, which may be closely relevant to post-injury brain rewiring. We also demonstrated that contralateral electrophysiological diaschisis could be greatly reversed by early reperfusion and is independent of the lesion size of striatum.

Context-dependent IL-6 potentiation of interferon- gamma-induced IL-12 secretion and CD40 expression in murine microglia.

Interleukin-6 (IL-6) is produced by neurons, astrocytes, and microglia, and elevated levels of IL-6 within the CNS have been documented in multiple neurological disorders including Alzheimer's disease, stroke, epilepsy, attention deficit disorder, cerebral palsy, and multiple sclerosis. Here, we sought to understand how IL-6 regulates microglial signal transduction and their immune properties. Using highly enriched cultures of neonatal murine microglia we show that IL-6 alone has direct effects on microglia as it activates STAT3 and extracellular signal-regulated kinase pathways in a time- and dose-dependent fashion and it enhances interferon-gamma (IFNgamma)-stimulated IL-12 secretion. However, other immune properties were only weakly modulated by IL-6 when administered without the soluble IL-6 receptor (sIL-6R). For instance, IFNgamma-induced expression of the co-stimulatory molecule, CD40 was dependent on sIL-6R administration. IL-6 with or without sIL-6R did not affect major histocompatability complex class II expression. In granulocyte-macrophage colony-stimulating factor (GMCSF)-induced dendritic cell-like microglia, IL-6/sIL-6R and IFNgamma stimulated an even greater increase in CD40 expression compared with primary microglia. Altogether, our results demonstrate that microglial responses to IL-6 are not simple in that the effects of IL-6 are context-dependent. In particular, the presence or absence of sIL-6R, IFNgamma or GMCSF will alter the type and amplitude of their response.

Effects of melatonin in experimental stroke models in acute, sub-acute, and chronic stages.

Melatonin (n-acetyl-5-methoxy-tryptamine), a naturally occurring indole produced mainly by the pineal gland, is a well known antioxidant. Stroke (cerebral ischemia) is the second leading cause of death worldwide. To date, however, effective and safe treatment for stroke remains unavailable. Melatonin is both lipid- and water-soluble and readily crosses the blood-brain barrier (BBB). Increasing evidence has shown that, in animal stroke models, administering melatonin significantly reduces infarct volume, edema, and oxidative damage and improves electrophysiological and behavioral performance. Here, we reviewed studies that assess effects of melatonin on cerebral ischemia in acute, sub-acute, and chronic stages. In addition to its potent antioxidant properties, melatonin exerts antiapoptotic, antiexcitotoxic, anti-inflammatory effects and promotes mitochondrial functions in animals with cerebral ischemia. Given that melatonin shows almost no toxicity to humans and possesses multifaceted protective capacity against cerebral ischemia, it is valuable to consider using melatonin in clinical trials on patients suffering from stroke.

Ciliary neurotrophic factor (CNTF) plus soluble CNTF receptor alpha increases cyclooxygenase-2 expression, PGE2 release and interferon-gamma-induced CD40 in murine microglia.

BACKGROUND: Ciliary neurotrophic factor (CNTF) has been regarded as a potent trophic factor for motor neurons. However, recent studies have shown that CNTF exerts effects on glial cells as well as neurons. For instance, CNTF stimulates astrocytes to secrete FGF-2 and rat microglia to secrete glial cell line-derived neurotrophic factor (GDNF), which suggest that CNTF exerts effects on astrocytes and microglia to promote motor neuron survival indirectly. As CNTF is structurally related to IL-6, which can stimulate immune functions of microglia, we hypothesized that CNTF might exert similar effects. METHODS: We performed 2-D and 1-D proteomic experiments with western blotting and flow cytometry to examine effects of CNTF on primary microglia derived from neonatal mouse brains. RESULTS: We show that murine microglia express CNTF receptor alpha (CNTFRalpha), which can be induced by interferon-gamma (IFNgamma). Whereas IL-6 activated STAT-3 and ERK phosphorylation, CNTF did not activate these pathways, nor did CNTF increase p38 MAP kinase phosphorylation. Using 2-D western blot analysis, we demonstrate that CNTF induced the dephosphorylation of a set of proteins and phosphorylation of a different set. Two proteins that were phosphorylated upon CNTF treatment were the LYN substrate-1 and beta-tubulin 5. CNTF weakly stimulated microglia, whereas a stronger response was obtained by adding exogenous soluble CNTFRalpha (sCNTFRalpha) as has been observed for IL-6. When used in combination, CNTF and sCNTFRalpha collaborated with IFNgamma to increase microglial surface expression of CD40 and this effect was quite pronounced when the microglia were differentiated towards dendritic-like cells. CNTF/sCNTFRalpha complex, however, failed to increase MHC class II expression beyond that induced by IFNgamma. The combination of CNTF and sCNTFRalpha, but not CNTF alone, enhanced microglial Cox-2 protein expression and PGE2 secretion (although CNTF was 30 times less potent than LPS). Surprisingly, Cox-2 production was enhanced 2-fold, rather than being inhibited, upon addition of a gp130 blocking antibody. CONCLUSION: Our studies indicate that CNTF can activate microglia and dendritic-like microglia similar to IL-6; however, unlike IL-6, CNTF does not stimulate the expected signaling pathways in microglia, nor does it appear to require gp130.

Ciliary neurotrophic factor and interleukin-6 differentially activate microglia.

Studies have shown that cytokines released following CNS injury can affect the supportive or cytotoxic functions of microglia. Interleukin-6 (IL-6)-family cytokines are among the injury factors released. To understand how microglia respond to IL-6 family cytokines, we examined the effects of ciliary neurotrophic factor (CNTF) and IL-6 on primary cultures of rat microglia. To assess the functional state of the cells, we assayed the expression of tumor necrosis factor-alpha (TNFalpha), interleukin-1beta (IL-1beta), and cyclooxygenase 2 (COX-2) following stimulation. We show that CNTF reduces COX-2 levels, whereas IL-6 increases the expression of IL-1beta, TNFalpha, and Cox-2. We also examined trophic factor expression and found that CNTF enhances glial cell-line derived neurotrophic factor (GDNF) mRNA and protein secretion, whereas IL-6 has no effect. Correspondingly, conditioned media from CNTF-stimulated microglia promote motor neuron survival threefold beyond controls, whereas IL-6-stimulated microglia decrease neuronal survival twofold. To understand better the signaling mechanisms responsible for the opposite responses of these IL-6-family cytokines, we examined STAT-3 and ERK phosphorylation in CNTF- and IL-6-stimulated microglia. IL-6 markedly increases STAT-3 and ERK phosphorylation after 20 min of treatment, whereas these signal transducers are weakly stimulated by CNTF across a range of doses. We conclude that CNTF modifies microglial activation to support neuronal survival and that IL-6 enhances their capacity to do harm, as a result of different modes of intracellular signaling.

Successful use of extracorporeal membrane oxygenation and drotrecogin alpha in patients with acute life-threatening myocarditis.

Acute fulminant myocarditis may present with cardiogenic shock refractory to inotropics and intra-aortic balloon pumping (IABP). Benefit of extracorporeal membrane oxygenation (ECMO) support has been established. The effectiveness of combination with ECMO or IABP and activated protein C (drotrecogin alpha; Xigris) in treatment has yet to be defined. Four patients presented with congestive heart failure 3-4 days after flu-like symptoms. Chest roentgenograms showed cardiomegaly and bilateral pulmonary infiltrates. Two-dimensional echocardiograms demonstrated severe myocardial dysfunction with left ventricular ejection fraction (LVEF), measured between 18.4% to 27% (mean, 19.5%). Three patients having been treated with the combination of ECMO or IABP and activated protein C were weaned. Follow-up LVEF measured were 39.9%, 43%, 53%, and 55%, respectively. However, 1 patient died a month later because of systemic lupus erythematosus and repeated infection. There were no neurologic sequelae in the 3 survivors. Serological test and myocardial biopsy for Parvovirus B19 was positive in 3 of 4 patients. Use of circulatory support and activated protein C is an effective alternative for acute life-threatening myocarditis.

Astrogliosis is delayed in type 1 interleukin-1 receptor-null mice following a penetrating brain injury.

The cytokines IL-1alpha and IL-1beta are induced rapidly after insults to the CNS, and their subsequent signaling through the type 1 IL-1 receptor (IL-1R1) has been regarded as essential for a normal astroglial and microglial/macrophage response. To determine whether abrogating signaling through the IL-1R1 will alter the cardinal astrocytic responses to injury, we analyzed molecules characteristic of activated astrocytes in response to a penetrating stab wound in wild type mice and mice with a targeted deletion of IL-1R1. Here we show that after a stab wound injury, glial fibrillary acidic protein (GFAP) induction on a per cell basis is delayed in the IL-1R1-null mice compared to wild type counterparts. However, the induction of chondroitin sulfate proteoglycans, tenascin, S-100B as well as glutamate transporter proteins, GLAST and GLT-1, and glutamine synthetase are independent of IL-1RI signaling. Cumulatively, our studies on gliosis in the IL-1R1-null mice indicate that abrogating IL-1R1 signaling delays some responses of astroglial activation; however, many of the important neuroprotective adaptations of astrocytes to brain trauma are preserved. These data recommend the continued development of therapeutics to abrogate IL-1R1 signaling to treat traumatic brain injuries. However, astroglial scar related proteins were induced irrespective of blocking IL-1R1 signaling and thus, other therapeutic strategies will be required to inhibit glial scarring.

Neuroinflammation and both cytotoxic and vasogenic edema are reduced in interleukin-1 type 1 receptor-deficient mice conferring neuroprotection.

BACKGROUND AND PURPOSE: Interleukin-1 (IL-1) is a proinflammatory cytokine implicated in multiple neurodegenerative diseases, including stroke. However, to date, there is no consensus regarding which receptor(s) mediates the detrimental effects of IL-1. We hypothesized that abrogating IL-1 type 1 receptor (IL-1R1) signaling would reduce edema, chemokine expression, and leukocyte infiltration; lower levels of iNOS; and, consequently, decrease free radical damage after mild hypoxia/ischemia (H/I), thus preserving brain cells. METHODS: IL-1R1 null mice and wild-type mice were subjected to a mild H/I insult. MRI was used to measure the area affected at 30 minutes and 48 hours after H/I. An RNAse protection assay was used to evaluate changes in chemokine mRNA expression. RT-PCR was used to assess inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase mRNA levels. Immunohistochemistry was used to assess leukocyte infiltration. Western blots were used to assess iNOS and glutamate aspartate transporter protein levels. RESULTS: IL-1R1 null mice had reduced cytotoxic and vasogenic edema. The volume of hyperintense signal on T2-weighted images was reduced on average by 90% at 48 hours after H/I. The induction of multiple chemokine mRNAs was significantly reduced in IL-1R1 null mice compared with wild-type mice at 18 and 72 hours after H/I, which correlated with fewer infiltrating CD3+ leukocytes. Levels of iNOS protein and mRNA (but not glutamate aspartate transporter) were significantly reduced in the IL-1R1 mouse brain. CONCLUSIONS: These findings indicate that abrogating IL-1R1 signaling could protect brain cells subsequent to a mild stroke by reducing edema and immune cell recruitment, as well as by limiting iNOS-mediated free radical damage.