PET-detectable tau pathology correlates with long-term neuropsychiatric outcomes in patients with traumatic brain injury.

Tau deposits is a core feature of neurodegenerative disorder following traumatic brain injury (TBI). Despite ample evidence from post-mortem studies demonstrating exposure to both mild-repetitive and severe TBIs are linked to tau depositions, associations of topology of tau lesions with late-onset psychiatric symptoms due to TBI have not been explored. To address this issue, we assessed tau deposits in long-term survivors of TBI by PET with 11C-PBB3, and evaluated those associations with late-life neuropsychiatric outcomes. PET data were acquired from 27 subjects in the chronic stage following mild-repetitive or severe TBI and 15 healthy control subjects. Among the TBI patients, 14 were diagnosed as having late-onset symptoms based on the criteria of traumatic encephalopathy syndrome. For quantification of tau burden in TBI brains, we calculated 11C-PBB3 binding capacity (cm3), which is a summed voxel value of binding potentials (BP*ND) multiplied by voxel volume. Main outcomes of the present study were differences in 11C-PBB3 binding capacity between groups, and the association of regional 11C-PBB3 binding capacity with neuropsychiatric symptoms. To confirm 11C-PBB3 binding to tau deposits in TBI brains, we conducted in vitro PBB3 fluorescence and phospho-tau antibody immunofluorescence labelling of brain sections of chronic traumatic encephalopathy obtained from the Brain Bank. Our results showed that patients with TBI had higher 11C-PBB3 binding capacities in the neocortical grey and white matter segments than healthy control subjects. Furthermore, TBI patients with traumatic encephalopathy syndrome showed higher 11C-PBB3 binding capacity in the white matter segment than those without traumatic encephalopathy syndrome, and regional assessments revealed that subgroup difference was also significant in the frontal white matter. 11C-PBB3 binding capacity in the white matter segment correlated with the severity of psychosis. In vitro assays demonstrated PBB3-positive tau inclusions at the depth of neocortical sulci, confirming 11C-PBB3 binding to tau lesions. In conclusion, increased 11C-PBB3 binding capacity is associated with late-onset neuropsychiatric symptoms following TBI, and a close correlation was found between psychosis and 11C-PBB3 binding capacity in the white matter.

Preparation and stability of ethanol-free solution of [18F]florbetapir ([18F]AV-45) for positron emission tomography amyloid imaging.

We have developed an ethanol-free formulation method of [(18) F]florbetapir ([(1) (8) F]AV-45) using a commercially available automated JFE multi-purpose synthesizer. We have also evaluated the radiochemical stability in an ethanol-free solution of [(18) F]AV-45 under visible light irradiation and dark conditions by comparison with a conventional 10% ethanol solution of [(18) F]AV-45. [(18) F]AV-45 was obtained with a radiochemical yield of 55.1 ± 2.2% (decay-corrected to end of bombardment), specific activity of 591.6 ± 90.3 GBq/µmol and radiochemical purity of >99% within a total synthesis time of about 73 min. The radiochemical purity of [(18) F]AV-45 formulated by dissolving the ethanol-free solution was found to decrease as a function of the period of exposure to visible light. In contrast, the visible light photolysis could be suppressed by adding 10% ethanol to the formulation or by avoiding exposure to visible light. In the radiosynthesis of [(18) F]AV-45 formulated by dissolving the ethanol-free solution, [(18) F]AV-45 could be obtained with high radiochemical purity and high stability by avoiding exposure to visible light.

Secondary prevention of stroke: Pleiotropic effects of optimal oral pharmacotherapy.

Stroke is a major cause of mortality and disability worldwide. During the past three decades, major advances have occurred in secondary prevention, which have demonstrated the broader potential for the prevention of stroke. Risk factors for stroke include previous stroke or transient ischemic attack, hypertension, high blood cholesterol and diabetes. Proven secondary prevention strategies are anti-platelet agents, antihypertensive drugs, statins and glycemic control. In the present review, we evaluated the secondary prevention of stroke in light of clinical studies and discuss new pleiotropic effects beyond the original effects and emerging clinical evidence, with a focus on the effect of optimal oral pharmacotherapy.

Beyond free radical scavenging: Beneficial effects of edaravone (Radicut) in various diseases (Review).

Free radicals play an important role in the pathogenesis of a variety of diseases; thus, they are an attractive target for therapeutic intervention in these diseases. Compounds capable of scavenging free radicals have been developed for this purpose and some, developed for the treatment of cerebral ischemic stroke, have progressed to clinical trials. One such scavenger, edaravone, is used to treat patients within 24 h of stroke. Edaravone, which can diffuse into many disease-affected organs, also shows protective effects in the heart, lung, intestine, liver, pancreas, kidney, bladder and testis. As well as scavenging free radicals, edaravone has anti-apoptotic, anti-necrotic and anti-cytokine effects in various diseases. Here, we critically review the literature on its clinical efficacy and examine whether edaravone should be considered a candidate for worldwide development, focusing on its effects on diseases other than cerebral infarction. Edaravone has been safely used as a free radical scavenger for more than 10 years; we propose that edaravone may offer a novel treatment option for several diseases.

Beyond neurological disease: new targets for edaravone (Review).

Free radicals play major roles in the pathogenesis of tissue damage in many diseases and clinical conditions, and the removal of free radicals may offer a treatment option. Several modulators of free radical scavenger pathways have been developed and some have progressed to clinical trials. One such agent, edaravone, was approved in 2001 in Japan for the treatment of cerebral infarction. It has since been shown that edaravone can diffuse into many organs and, in addition to its effects on hydroxyl radical removal, edaravone modulates inflammatory processes, matrix metalloproteinase levels, nitric oxide production, apoptotic cell death, and necrotic cell death. Edaravone also exerts protective effects in a number of animal models of disease and tissue damage, including models of myocardial, lung, intestinal, liver, pancreatic and renal injury. Together with the proven safety of edaravone following 9 years of use as a modulator of free radical scavenging pathways in neurological disease, these additional effects of edaravone suggest that it may offer a novel treatment for several non-neurological diseases and clinical conditions in humans.

1,5-Anhydro-D-fructose: A natural antibiotic that inhibits the growth of gram-positive bacteria and microbial biofilm formation to prevent nosocomial infection.

Nosocomial infections caused by microbial opportunistic infections or microbial biofilms may occur during hospitalization and increase patient morbidity, mortality and health care costs. Artificial antibiotic agents were initially used to prevent infection; however, the high prevalence of nosocomial infections has resulted in their excessive use, which has led to microbial resistance to these agents. The increase in microbial resistance to antibiotics and the development of antibiotic agents may be the cause of the production of other microbial resistance. Thus, natural compounds that have no adverse side effects would be a preferred treatment modality. Recently, the monosaccharide 1,5-anhydro-D-fructose (1,5-AF), a natural plant compound derived from starch, has been found to have multifunctional properties, including antioxidant, antiplatelet aggregation by thrombin and anti-inflammatory activities. The results of the present study demonstrate that 1,5-AF suppressed the growth of coagulase-negative staphylococci on the hands as well as the growth of Staphylococcus epidermidis, which is a cause of opportunistic infections. Furthermore, 1,5-AF suppressed biofilm formation by the methicillin-resistant Staphylococcus aureus. In conclusion, 1,5-AF is a natural compound that may be effective in preventing nosocomial infections, without causing adverse side effects.

HMGB1 as a therapeutic target in spinal cord injury: A hypothesis for novel therapy development.

Historically, clinical outcomes following spinal cord injury (SCI) have been dismal. Severe SCI leads to devastating neurological deficits, and there is no treatment available that restores the injury-induced loss of function to a degree that an independent life can be guaranteed. To address all the issues associated with SCI, a multidisciplinary approach is required, as it is unlikely that a single approach, such as surgical intervention, pharmacotherapy or cellular transplantation, will suffice. High mobility group box 1 (HMGB1) is an inflammatory cytokine. Various studies have shown that HMGB1 plays a critical role in SCI and that inhibition of HMGB1 release may be a novel therapeutic target for SCI and may support spinal cord repair. In addition, HMGB1 has been associated with graft rejection in the early phase. Therefore, HMGB1 may be a promising therapeutic target for SCI transplant patients. We hypothesize that inhibition of HMGB1 release rescues patients with SCI. Taken together, our findings suggest that anti-HMGB1 monoclonal antibodies or short hairpin RNA-mediated HMGB1 could be administered for spinal cord repair in SCI patients.

Potential of edaravone for neuroprotection in neurologic diseases that do not involve cerebral infarction.

Edaravone was originally developed as a potent free radical scavenger and has been widely used to treat cerebral infarction in Japan since 2001. Several free radical scavengers have been developed and some of them have progressed to clinical trials for the treatment of cerebral infarction. One such scavenger, edaravone, has been approved by the regulatory authority in Japan for the treatment of patients with cerebral infarction. Of particular interest is the ability of edaravone to diffuse into the central nervous system in various neurologic diseases. Aside from its hydroxyl radical scavenging effect, edaravone has been found to have beneficial effects on inflammation, matrix metalloproteinases, nitric oxide production and apoptotic cell death. Concordantly, edaravone has been found to have neuroprotective effects in a number of animal models of disease, including stroke, spinal cord injury, traumatic brain injury, neurodegenerative diseases and brain tumors. The proven safety of edaravone following 9 years of use as a free radical scavenger suggests that it may have potential for development into an effective treatment of multiple neurologic conditions in humans.

[Activation syndrome in the Japanese court].

Since the February 2004 FDA advisory's warning of activation syndrome involving antidepressants, growing concerns have emerged over aggression and violence reported in subjects prescribed these drugs. However, activation syndrome remains poorly defined, and controversy regarding the nature of this syndrome continues in the field of psychiatry. Here, we present four medico-legal cases involving activation syndrome, in which one of us served as an expert witness. Analysis of the court's decisions indicated that the court appeared to focus on whether the acts were associated with the subjects' personality or not, leaving the controversy over activation syndrome as an open question. These cases highlighted the need for joint examination by jurists and psychiatrists, since society is likely to continue to be faced with cases of behavioral problems associated with the use of antidepressants.

Edaravone: a new therapeutic approach for the treatment of acute stroke.

Acute stroke, including acute ischemic stroke (AIS) and acute hemorrhagic stroke, (AHS) is a common medical problem with particular relevance to the demographic changes in industrialized societies. In recent years, treatments for AIS have emerged, including thrombolysis with tissue plasminogen activator (t-PA). Although t-PA is the most effective currently available therapy, it is limited by a narrow therapeutic time window and side effects, and only 3% of all AIS patients receive thrombolysis. Edaravone was originally developed as a potent free radical scavenger and, since 2001, has been widely used to treat AIS in Japan. It was shown that edaravone extended the narrow therapeutic time window of t-PA in rats. The therapeutic time window is very important for the treatment of AIS, and early edaravone treatment is more effective. Thus, more AIS patients might be rescued by administering edaravone with t-PA. Meanwhile, edaravone attenuates AHS-induced brain edema, neurologic deficits and oxidative injury in rats. Although edaravone treatment is currently only indicated for AIS, it does offer neuroprotective effects against AHS in rats. Therefore, we hypothesize that early administration of edaravone can rescue AHS patients as well as AIS patients. Taken together, our findings suggest that edaravone should be immediately administered on suspicion of acute stroke, including AIS and AHS.

HMGB1: A new marker for estimation of the postmortem interval.

Estimation of the postmortem interval (PMI) is one of the most important tasks in forensic medicine. Numerous methods have been proposed for the determination of the time since death by chemical means. High mobility group box-1 (HMGB1), a nonhistone DNA-binding protein is released by eukaryotic cells upon necrosis. Postmortem serum levels of HMGB1 of 90 male Wistar rats stored at 4, 14 and 24°C since death were measured by enzyme-linked immunosorbent assay. The serum HMGB1 level showed a time-dependent increase up to seven days at 4°C. At 14°C, the HMGB1 level peaked at day 3, decreased at day 4, and then plateaued. At 24°C, the HMGB1 level peaked at day 2, decreased at day 3, and then plateaued. Our findings suggest that HMGB1 is related to the PMI in rats.

Edaravone attenuates cerebral ischemic injury by suppressing aquaporin-4.

Aquaporin-4 (AQP4) plays a role in the generation of post-ischemic edema. Pharmacological modulation of AQP4 function may thus provide a novel therapeutic strategy for the treatment of stroke, tumor-associated edema, epilepsy, traumatic brain injury, and other disorders of the central nervous system (CNS) associated with altered brain water balance. Edaravone, a free radical scavenger, is used for the treatment of acute ischemic stroke (AIS) in Japan. In this study, edaravone significantly reduced the infarct area and improved the neurological deficit scores at 24h after reperfusion in a rat transient focal ischemia model. Furthermore, edaravone markedly reduced AQP4 immunoreactivity and protein levels in the cerebral infarct area. In light of observations that edaravone specifically inhibited AQP4 in a rat transient focal ischemia model, we propose that edaravone might reduce cerebral edema through the inhibition of AQP4 expression following cerebral infarction.

MK615 attenuates Porphyromonas gingivalis lipopolysaccharide-induced pro-inflammatory cytokine release via MAPK inactivation in murine macrophage-like RAW264.7 cells.

The Japanese apricot, known as Ume in Japanese, has been a traditional Japanese medicine for centuries, and is a familiar and commonly consumed food. The health benefits of Ume are now being widely recognized and have been strengthened by recent studies showing that MK615, an extract of compounds from Ume, has strong anticancer and anti-inflammatory effects. However, the potential role of MK615 in the periodontal field remains unknown. Here, we found that MK615 significantly reduced the production of pro-inflammatory mediators (tumor necrosis factor-alpha and interleukin-6) induced by Porphyromonas gingivalis lipopolysaccharide (LPS), a major etiological agent in localized chronic periodontitis, in murine macrophage-like RAW264.7 cells. MK615 markedly inhibited the phosphorylation of ERK1/2, p38MAPK, and JNK, which is associated with pro-inflammatory mediator release pathways. Moreover, MK615 completely blocked LPS-triggered NF-kappaB activation. The present results suggest that MK615 has potential as a therapeutic agent for treating inflammatory diseases such as periodontitis.

Minocycline attenuates both OGD-induced HMGB1 release and HMGB1-induced cell death in ischemic neuronal injury in PC12 cells.

High mobility group box-1 (HMGB1), a non-histone DNA-binding protein, is massively released into the extracellular space from neuronal cells after ischemic insult and exacerbates brain tissue damage in rats. Minocycline is a semisynthetic second-generation tetracycline antibiotic which has recently been shown to be a promising neuroprotective agent. In this study, we found that minocycline inhibited HMGB1 release in oxygen-glucose deprivation (OGD)-treated PC12 cells and triggered the activation of p38mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinases (ERK1/2). The ERK kinase (MEK)1/2 inhibitor U-0126 and p38MAPK inhibitor SB203580 blocked HMGB1 release in response to OGD. Furthermore, HMGB1 triggered cell death in a dose-dependent fashion. Minocycline significantly rescued HMGB1-induced cell death in a dose-dependent manner. In light of recent observations as well as the good safety profile of minocycline in humans, we propose that minocycline might play a potent neuroprotective role through the inhibition of HMGB1-induced neuronal cell death in cerebral infarction.

Mechanism of HMGB1 release inhibition from RAW264.7 cells by oleanolic acid in Prunus mume Sieb. et Zucc.

High mobility group box-1 protein (HMGB1), primarily from the nucleus, is released into the extracellular milieu either passively from necrotic cells or actively through secretion by monocytes/macrophages. Extracellular HMGB1 acts as a potent inflammatory agent by promoting the release of cytokines such as tumor necrosis factor (TNF)-alpha, has procoagulant activity, and is involved in death due to sepsis. Accordingly, HMGB1 is an appropriate therapeutic target. In this study, we found that an extract of Prunus mume Sieb. et Zucc. (Ume) fruit (Ume extract), an abundant source of triterpenoids, strongly inhibited HMGB1 release from lipopolysaccharide (LPS)-stimulated macrophage-like RAW264.7 cells. The inhibitory effect on HMGB1 release was enhanced by authentic oleanolic acid (OA), a naturally occurring triterpenoid. Similarly, the HMGB1 release inhibitor in Ume extract was found to be OA. Regarding the mechanisms of the inhibition of HMGB1 release, the OA or Ume extract was found to activate the transcription factor Nrf2, which binds to the antioxidative responsive element, and subsequently the heme oxygenase (HO)-1 protein was induced, indicating that the inhibition of HMGB1 release from LPS-stimulated RAW264.7 cells was mediated via the Nrf2/HO-1 system; an essentially antioxidant effect. These results suggested that natural sources of triterpenoids warrant further evaluation as 'rescue' therapeutics for sepsis and other potentially fatal systemic inflammatory disorders.

The free radical scavenger edaravone rescues rats from cerebral infarction by attenuating the release of high-mobility group box-1 in neuronal cells.

Edaravone, a potent free radical scavenger, is clinically used for the treatment of cerebral infarction in Japan. Here, we examined the effects of edaravone on the dynamics of high-mobility group box-1 (HMGB1), which is a key mediator of ischemic-induced brain damage, during a 48-h postischemia/reperfusion period in rats and in oxygen-glucose-deprived (OGD) PC12 cells. HMGB1 immunoreactivity was observed in both the cytoplasm and the periphery of cells in the cerebral infarction area 2 h after reperfusion. Intravenous administration of 3 and 6 mg/kg edaravone significantly inhibited nuclear translocation and HMGB1 release in the penumbra area and caused a 26.5 +/- 10.4 and 43.8 +/- 0.5% reduction, respectively, of the total infarct area at 24 h after reperfusion. Moreover, edaravone also decreased plasma HMGB1 levels. In vitro, edaravone dose-dependently (1-10 microM) suppressed OGD- and H(2)O(2)-induced HMGB1 release in PC12 cells. Furthermore, edaravone (3-30 microM) blocked HMGB1-triggered apoptosis in PC12 cells. Our findings suggest a novel neuroprotective mechanism for edaravone that abrogates the release of HMGB1.

Induction of high mobility group box 1 release from serotonin-stimulated human umbilical vein endothelial cells.

High mobility group box 1 (HMGB1) is a non-histone nuclear protein which is released from the nucleus of activated macrophages into the extracellular space in response to stimuli such as endotoxin or necrosis. The HMGB1 functions as a potent proinflammatory cytokine in the extracellular spaces. Recently, HMGB1 has been implicated in the progression of atherosclerosis. However, the association between HMGB1 and the development of atherosclerosis is poorly understood. Therefore, we examined whether serotonin (5-HT), a key factor involved in the development of atherosclerosis, induced HMGB1 release in human umbilical vein endothelial cells (HUVECs). We found that 5-HT induced the release of HMGB1 but not of ERK1/2 and JNK from HUVECs via the 5-HT receptor (5-HT1B)/p38 mitogen-activated protein kinase (MAPK) signaling pathway. The p38MAPK inhibitor SB203580 and the 5-HT1B antagonist GR55526 markedly inhibited HMGB1 release from 5-HT-stimulated HUVECs. The vascular endothelial growth factor (VEGF) derived from activated macrophages in atherosclerotic lesions also plays an important role in the progression of atherosclerosis. We found that HMGB1 induced VEGF production in macrophage-like RAW264.7 cells. HMGB1 induced the activation of p38MAPK, ERK1/2 and Akt. The PI3-kinase inhibitor LY294002 significantly inhibited VEGF production in HMGB1-stimulated macrophages, while other kinase inhibitors did not. These results suggest that HMGB1 release may contribute as a risk factor in the development and progression of atherosclerosis.

C-reactive protein induces high-mobility group box-1 protein release through activation of p38MAPK in macrophage RAW264.7 cells.

BACKGROUND: C-reactive protein (CRP) is widely used as a sensitive biomarker for inflammation. Increasing evidence suggests that CRP plays a role in inflammation. High-mobility group box-1 (HMGB1), a primarily nuclear protein, is passively released into the extracellular milieu by necrotic or damaged cells and is actively secreted by monocytes/macrophages. Extracellular HMGB1 as a potent inflammatory mediator has stimulated immense curiosity in the field of inflammation research. However, the molecular dialogue implicated between CRP and HMGB1 in delayed inflammatory processes remains to be explored. METHODS AND RESULTS: The levels of HMGB1 in culture supernatants were determined by Western blot analysis and enzyme-linked immunosorbent assay in macrophage RAW264.7 cells. Purified CRP induced the release of HMGB1 in a dose- and time-dependent fashion. Immunofluorescence analysis revealed nuclear translocation of HMGB1 in response to CRP. The binding of CRP to the Fc gamma receptor in RAW264.7 cells was confirmed by fluorescence-activated cell sorter analysis. Pretreatment of cells with IgG-Fc fragment, but not IgG-Fab fragment, efficiently blocked this binding. CRP triggered the activation of p38MAPK and ERK1/2, but not Jun N-terminal kinase. Moreover, both p38MAPK inhibitor SB203580 and small interfering RNA significantly suppressed the release of HMGB1, but not the MEK1/2 inhibitor U-0126. CONCLUSION: We demonstrated for the first time that CRP, a prominent risk marker for inflammation including atherosclerosis, could induce the active release of HMGB1 by RAW264.7 cells through Fc gamma receptor/p38MAPK signaling pathways, thus implying that CRP plays a crucial role in the induction, amplification, and prolongation of inflammatory processes, including atherosclerotic lesions.

HMGB1 release in co-cultures of porcine endothelial and human T cells.

High mobility group box-1 (HMGB1) protein, primarily from the nucleus, is released into the extracellular milieu either passively by necrotic or damaged cells, or actively by secretion from monocytes/macrophages. Extracellular HMGB1 acts as a potent inflammatory stimulator by promoting cytokine (for example, tumor necrosis factor-alpha) production, and also has pro-coagulant activity. The signaling pathway initiated by receptor for advanced glycation end-product (RAGE), which is the HMGB1 receptor, also induces complement activation. Recent studies have implicated HMGB1 in acute cardiac allograft rejection, and have identified infiltrating T cells and other damaged cells as its main sources. HMGB1 blockade using the anti-HMGB1 antibody HMGB1 box-A (amino-terminal region) and soluble RAGE rescues mice from acute rejection. We therefore studied the release of HMGB1 in co-cultures of porcine aortic endothelial cells (PAEC) and human leukocytes. Human T cells, but not B cells, monocytes or neutrophils, stimulated significant HMGB1 release in culture with PAEC; this activity required cell-cell contact and was dose-dependent, as determined by Western blotting. The released HMGB1 originated from both cell types, as immunofluorescent microscopy showed that it was present in the cytosol of PAEC in contact with T cells, and had disappeared from the T-cell nuclei. These results demonstrate that direct interactions between PAEC and T cells might be a key factor in triggering HMGB1 release, which suggests that HMGB1 is associated with graft rejection in the early phase.