Dexamethasone diminishes the pro-inflammatory and cytotoxic effects of amyloid beta-protein in cerebrovascular smooth muscle cells

Repeated recurrent intracerebral hemorrhage may be involved in cerebral amyloid angiopathy-related inflammation: An autopsy case

We report an autopsy case of repeated recurrent intracerebral hemorrhage (ICH) diagnosed as having cerebral amyloid angiopathy-related inflammation (CAA-ri) in a 65-year-old woman. She had no history of hypertension or other risk factors for stroke. She had a history of lobar ICH in the right parietal lobe 30 months prior. Follow-up magnetic resonance imaging (MRI) performed 29 months after the initial ICH revealed superficial siderosis in the left frontal lobe. She initially presented with severe headache and dysarthria. An initial computed tomography (CT) revealed a subarachnoid hemorrhage on the left frontal lobe. One hour later, an epileptic seizure occurred, and another CT performed at the time revealed lobar ICH in the frontal lobe. Emergency surgical hematoma evacuation was performed. The cortical artery was removed from the surgical specimen. Hematoxylin and eosin (HE) staining revealed lymphocytic perivascular cuffs, and immunohistochemical staining revealed abundant amyloid-β (Aβ) deposits. The patient was diagnosed as having CAA-ri. On the next day, and 19, 46, 55, 78, 79, and 85 days after admission, ICH recurred. We did not administer immunosuppressive drugs, such as high-dose corticosteroids or cyclophosphamide, because of the patient's condition. Following the last ICH, the patient died on the 90th day after symptom onset. An autopsy was performed. Histologically, abundant Aβ deposits were observed within the leptomeningeal and cortical arteries. Further dense-cored amyloid plaques were observed in the cortical samples. Our findings that ICH occurred initially three times in the left hemispheres and later five times in the right hemispheres were considered immune-mediated effects on vascular function. Further, superficial hemosiderosis in the left frontal lobe occurred before the first three ICH events, and hyperintensity of the white matter on MRI was identified in the right parietal lobe, a typical finding of CAA-ri. We hypothesize that the inflammatory process in CAA-ri may be related to recurrent ICH.

MFG-E8 (LACTADHERIN): a novel marker associated with cerebral amyloid angiopathy

Brain accumulation of amyloid-beta (Aβ) is a crucial feature in Alzheimer´s disease (AD) and cerebral amyloid angiopathy (CAA), although the pathophysiological relationship between these diseases remains unclear. Numerous proteins are associated with Aβ deposited in parenchymal plaques and/or cerebral vessels. We hypothesized that the study of these proteins would increase our understanding of the overlap and biological differences between these two pathologies and may yield new diagnostic tools and specific therapeutic targets. We used a laser capture microdissection approach combined with mass spectrometry in the APP23 transgenic mouse model of cerebral-β-amyloidosis to specifically identify vascular Aβ-associated proteins. We focused on one of the main proteins detected in the Aβ-affected cerebrovasculature: MFG-E8 (milk fat globule-EGF factor 8), also known as lactadherin. We first validated the presence of MFG-E8 in mouse and human brains. Immunofluorescence and immunoblotting studies revealed that MFG-E8 brain levels were higher in APP23 mice than in WT mice. Furthermore, MFG-E8 was strongly detected in Aβ-positive vessels in human postmortem CAA brains, whereas MFG-E8 was not present in parenchymal Aβ deposits. Levels of MFG-E8 were additionally analysed in serum and cerebrospinal fluid (CSF) from patients diagnosed with CAA, patients with AD and control subjects. Whereas no differences were found in MFG-E8 serum levels between groups, MFG-E8 concentration was significantly lower in the CSF of CAA patients compared to controls and AD patients. Finally, in human vascular smooth muscle cells MFG-E8 was protective against the toxic effects of the treatment with the Aβ40 peptide containing the Dutch mutation. In summary, our study shows that MFG-E8 is highly associated with CAA pathology and highlights MFG-E8 as a new CSF biomarker that could potentially be used to differentiate cerebrovascular Aβ pathology from parenchymal Aβ deposition.

Cerebral amyloid angiopathy and related inflammatory disorders

Inflammatory cerebral amyloid angiopathy is a largely reversible inflammatory vasculopathy that develops in an acute or subacute fashion in reaction to amyloid protein deposition in the central nervous system blood vessels. There are two recognized pathologically characterized variants: cerebral amyloid angiopathy-related inflammation (CAAri) and A beta-related angiitis (ABRA). Both variants produce a clinical picture that resembles primary angiitis of the CNS but is distinguished by a characteristic radiologic appearance. Although originally defined as a clinicopathologic diagnosis, it can now often be diagnosed based on clinicoradiologic criteria, though confirmation with brain and meningeal biopsy is still required in some cases. This disorder typically responds to steroids but addition of other immune suppressants may be needed in some cases to control the disease.

Dexamethasone does not ameliorate gliosis in a mouse model of neurodegenerative disease

Prolonged neuroinflammation is a driving force for neurodegenerative disease, and agents against inflammatory responses are regarded as potential treatment strategies. Here we aimed to evaluate the prevention effects on gliosis by dexamethasone (DEX), an anti-inflammation drug. We used DEX to treat the nicastrin conditional knockout (cKO) mouse, a neurodegenerative mouse model. DEX (10 mg/kg) was given to 2.5-month-old nicastrin cKO mice, which have not started to display neurodegeneration and gliosis, for 2 months. Immunohistochemistry (IHC) and Western blotting techniques were used to detect changes in neuroinflammatory responses. We found that activation of glial fibrillary acidic protein (GFAP) positive or ionized calcium binding adapter molecule1 (Iba1) positive cells was not inhibited in nicastrin cKO mice treated with DEX as compared to those treated with saline. These data suggest that DEX does not prevent or ameliorate gliosis in a neurodegenerative mouse model when given prior to neuronal or synaptic loss.

Dexamethasone, Intravenous Immunoglobulin, and Rituximab Combination Immunotherapy for Pediatric Opsoclonus-Myoclonus Syndrome

BACKGROUND

Although pulse-dose dexamethasone is increasingly favored for treating pediatric opsoclonus-myoclonus syndrome (OMS), and multimodal immunotherapy is associated with improved clinical response, there have been no neuroimmunologic studies of dexamethasone-based multimodal disease-modifying therapy.

METHODS

In this observational retrospective study, 19 children with OMS (with or without associated neuroblastoma) underwent multibiomarker evaluation for neuroinflammation. Nine children of varying OMS severity, duration, and treatment status were treated empirically with pulse dexamethasone, intravenous immunoglobulin (IVIg), and rituximab combination immunotherapy (DEXIR-CI). Another 10 children on dexamethasone alone or with IVIg at initial evaluation only provided a comparison group. Motor severity (total score) was scored rater-blinded via videotapes using the validated OMS Evaluation Scale.

RESULTS

DEXIR-CI was associated with a 69% reduction in group total score (P = 0.004) and was clinically well tolerated. Patients given the dexamethasone combination exhibited significantly lowered B cell frequencies in cerebrospinal fluid (-94%) and blood (-76%), normalizing the cerebrospinal fluid B cell percentage. The number of patients with positive inflammatory markers dropped 87% (P = 0.002) as did the number of markers. Cerebrospinal fluid oligoclonal bands were positive in four of nine pretreatment patients but zero of six post-treatment patients. In the comparison group, partial response to dexamethasone alone or with IVIg was associated with multiple positive markers for neuroinflammation despite an average of seven months of treatment.

CONCLUSIONS

Multimechanistic dexamethasone-based combination immunotherapy increases the therapeutic armamentarium for OMS, providing a viable option for less severely affected individuals. Partial response to dexamethasone with or without IVIg is indicative of ongoing neuroinflammation and should be treated promptly and accordingly.

Exploring the potential of natural and synthetic neuroprotective steroids against neurodegenerative disorders: A literature review

Neurodegeneration is a complex process, which leads to progressive brain damage due to loss of neurons. Despite exhaustive research, the cause of neuronal loss in various degenerative disorders is not entirely understood. Neuroprotective steroids constitute an important line of attack, which could play a major role against the common mechanisms associated with various neurodegenerative disorders like Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Natural endogenous steroids induce the neuroprotection by protecting the nerve cells from neuronal injury through multiple mechanisms, therefore the structural modifications of the endogenous steroids could be helpful in the generation of new therapeutically useful neuroprotective agents. The review article will keep the readers apprised of the detailed description of natural as well as synthetic neuroprotective steroids from the medicinal chemistry point of view, which would be helpful in drug discovery efforts aimed toward neurodegenerative diseases.

MMP-8 Is Critical for Dexamethasone Therapy in Alkali-Burned Corneas Under Dry Eye Conditions

Our previous studies have shown that Dexamethasone (Dex) reduced the expression of matrix-metalloproteinases (MMPs -1,-3,-9,-13), IL-1β and IL-6, while it significantly increased MMP-8 mRNA transcripts in a concomitant dry eye and corneal alkali burn murine model (CM). To investigate if MMP-8 induction is responsible for some of the protective effects of Dex in CM, MMP-8 knock out mice (MMP-8KO) were subjected to the CM for 2 or 5 days and topically treated either with 2 μl of 0.1% Dexamethasone (Dex), or saline QID. A separate group of C57BL/6 mice were topically treated with Dex or BSS and received either 100 nM CAM12 (MMP-8 inhibitor) or vehicle IP, QD. Here we demonstrate that topical Dex treated MMP-8KO mice subjected to CM showed reduced corneal clarity, increased expression of inflammatory mediators (IL-6, CXCL1, and MMP-1 mRNA) and increased neutrophil infiltration at 2D and 5D compared to Dex treated WT mice. C57BL/6 mice topically treated with Dex and CAM12 IP recapitulated findings seen with MMP-8KO mice. These results suggest that some of the anti-inflammatory effects of Dex are mediated through increased MMP-8 expression. J. Cell. Physiol. 231: 2506-2516, 2016. © 2016 Wiley Periodicals, Inc.

[A subacute dementia: Inflammatory cerebral amyloid angiopathy]

We report a case of inflammatory cerebral amyloid angiopathy (CAA) that led to rapid cognitive decline, seizures, visual hallucinations, hyperproteinorrachia and right hemispheric leukopathy. Brain biopsy gave the diagnosis of CAA. Although no inflammatory infiltrate was found in the biopsy sample, corticosteroids led to a regression of the radiological lesions without significant clinical improvement. CAA is a rare disease, defined by lesions of classical cerebral amyloid angiopathy and perivascular infiltrates in contact with the affected vessels. In cases of rapidly progressive dementia associated with leukopathy, inflammatory amyloid angiopathy should be considered as cognitive disorders may improve after immunosuppressive therapy.

Recurrence of Lobar Hemorrhage: A Red Flag for Cerebral Amyloid Angiopathy-related Inflammation?

Background. Recurrent lobar intracerebral hemorrhage is more commonly associated with cerebral amyloid angiopathy and less likely associated with hypertension. Cerebral amyloid angiopathy-related inflammation is a subgroup of cerebral amyloid angiopathy that can present with lobar intracerebral hemorrhage, encephalopathy, and seizures; wherein corticosteroids may facilitate favorable outcome. Whether recurrence of lobar intracerebral hemorrhage in cerebral amyloid angiopathy is related to cerebral amyloid angiopathy-related inflammation is unknown. Case presentation. A 68-year-old woman presented with an acute onset of confusion. She was known to have a history of recurrent lobar intracerebral hemorrhage related to cerebral amyloid angiopathy. Brain imaging revealed previous sequelae of cerebral amyloid angiopathy and a new lobar intracerebral hemorrhage. An empirical diagnosis of cerebral amyloid angiopathy-related inflammation was made given the patent's clinical course of recurrence. Utilizing current evidence of criteria used to diagnose cerebral amyloid angiopathy-related inflammation, corticosteroid therapy was initiated with significant improvement in clinical and imaging characteristics. Discussion. Inflammatory pathways incited as a result of cerebrovascular amyloid deposition play a vital role in pathogenesis of cerebral amyloid angiopathy-related inflammation. We highlight the need to consider corticosteroid therapy in patients presenting with recurrent lobar intracerebral hemorrhage in the setting of cerebral amyloid angiopathy since inflammation may play a role in its pathophysiology. Evidence in the literature is sparse to suggest that cerebral amyloid angiopathy-related inflammation might be the root cause for the lobar intracerebral hemorrhage recurrence in cerebral amyloid angiopathy. Further studies are needed to identify mechanisms of recurrent hemorrhage, its correlations with cerebral amyloid angiopathy-related inflammation, and the potential role of corticosteroid therapy.

Multimodal nanoprobes to target cerebrovascular amyloid in Alzheimer's disease brain

Cerebral amyloid angiopathy (CAA) results from the accumulation of Aβ proteins primarily within the media and adventitia of small arteries and capillaries of the cortex and leptomeninges. CAA affects a majority of Alzheimer's disease (AD) patients and is associated with a rapid decline in cognitive reserve. Unfortunately, there is no pre-mortem diagnosis available for CAA. Furthermore, treatment options are few and relatively ineffective. To combat this issue, we have designed nanovehicles (nanoparticles-IgG4.1) capable of targeting cerebrovascular amyloid (CVA) and serving as early diagnostic and therapeutic agents. These nanovehicles were loaded with Gadolinium (Gd) based (Magnevist(®)) magnetic resonance imaging contrast agents or single photon emission computed tomography (SPECT) agents, such as (125)I. In addition, the nanovehicles carry either anti-inflammatory and anti-amyloidogenic agents such as curcumin or immunosuppressants such as dexamethasone, which were previously shown to reduce cerebrovascular inflammation. Owing to the anti-amyloid antibody (IgG4.1) grafted on the surface, the nanovehicles are capable of specifically targeting CVA deposits. The nanovehicles effectively marginate from the blood flow to the vascular wall as determined by using quartz crystal microbalance with dissipation monitoring (QCM-D) technology. They demonstrate excellent distribution to the brain vasculature and target CVA, thus providing MRI and SPECT contrast specific to the CVA in the brain. In addition, they also display the potential to carry therapeutic agents to reduce cerebrovascular inflammation associated with CAA, which is believed to trigger hemorrhage in CAA patients.

β-Amyloid context intensifies vascular smooth muscle cells induced inflammatory response and de-differentiation

Several studies have shown that the accumulation of β-amyloid peptides in the brain parenchyma or vessel wall generates an inflammatory environment. Some even suggest that there is a cause-and-effect relationship between inflammation and the development of Alzheimer's disease and/or cerebral amyloid angiopathy (CAA). Here, we studied the ability of wild-type Aβ1-40 -peptide (the main amyloid peptide that accumulates in the vessel wall in sporadic forms of CAA) to modulate the phenotypic transition of vascular smooth muscle cells (VSMCs) toward an inflammatory/de-differentiated state. We found that Aβ1-40 -peptide alone neither induces an inflammatory response, nor decreases the expression of contractile markers; however, the inflammatory response of VSMCs exposed to Aβ1-40 -peptide prior to the addition of the pro-inflammatory cytokine IL-1β is greatly intensified compared with IL-1β-treated VSMCs previously un-exposed to Aβ1-40 -peptide. Similar conclusions could be drawn when tracking the decline of contractile markers. Furthermore, we found that the mechanism of this potentiation highly depends on an Aβ1-40 preactivation of the PI3 Kinase and possibly NFκB pathway; indeed, blocking the activation of these pathways during Aβ1-40 -peptide treatment completely suppressed the observed potentiation. Finally, strengthening the possible in vivo relevance of our findings, we evidenced that endothelial cells exposed to Aβ1-40 -peptide generate an inflammatory context and have similar effects than the ones described with IL-1β. These results reinforce the idea that intraparietal amyloid deposits triggering adhesion molecules in endothelial cells, contribute to the transition of VSMCs to an inflammatory/de-differentiated phenotype. Therefore, we suggest that acute inflammatory episodes may increase vascular alterations and contribute to the ontogenesis of CAA.

Encephalopathy with amyloid angiopathy and numerous amyloid plaques with low levels of CSF Aβ1-40/Aβ1-42

A middle-aged male suffering from encephalopathy with cerebral amyloid angiopathy (CAA) with amyloid beta (Aβ) presented with initial symptoms of transient consciousness disturbance and left visual field photophobia. Lesions with aberrantly high signal on T2-weighted magnetic resonance imaging (MRI) of the brain appeared in the right temporal lobe posterior to the occipital lobe and spread to other areas. Brain biopsy revealed Aβ deposits in vascular walls and numerous diffuse plaques in parenchymal areas. Based on MRI findings, Initial corticosteroid therapy with beta methasone effectively improved the neurological symptoms of consciousness disturbance and motor deficits. After corticosteroid therapy was stopped at 4 weeks, recurrence occurred. Additional corticosteroids did not improve clinical symptoms and the patient progressed to a bed-ridden state with a severe consciousness disturbance. Notably, CSF Aβ1-42 and CSF Aβ1-40 decreased while the recurrent encephalopathy worsened. After intense deterioration, the patient became stable. CSF Aβ1-42 increased but remained at a very low level. This case of CAA encephalopathy with apolipoprotein E ϵ4/ϵ4 homozygosity showed Aβ deposits in vascular walls and numerous diffuse plaques in parenchymal areas. The clinical course suggests that reduction of CSF Aβ1-42 and Aβ1-40 might be related to clinical deterioration in cases of encephalopathy.

Steroid responsive encephalopathy in cerebral amyloid angiopathy: a case report and review of evidence for immunosuppressive treatment

Cerebral amyloid angiopathy (CAA) is a common but often asymptomatic disease, characterized by deposition of amyloid in cerebral blood vessels. We describe the successful treatment of CAA encephalopathy with dexamethasone in a patient with CAA-related inflammation causing subacute progressive encephalopathy and seizures, which is an increasingly recognized subtype of CAA. The two pathological subtypes of CAA-related inflammation are described and a review of the literature is performed concerning immunosuppressive treatment of CAA-related inflammation with special attention to its pathological subtypes. Immunosuppressive therapy appears to be an appropriate treatment for CAA encephalopathy.

Targeting p38 MAPK pathway for the treatment of Alzheimer's disease

Accumulating evidence indicates that p38 mitogen-activated protein kinase (MAPK) could play more than one role in Alzheimer's disease (AD) pathophysiology and that patients suffering from AD dementia could benefit from p38 MAPK inhibitors. The p38 MAPK signalling has been widely accepted as a cascade contributing to neuroinflammation. However, deepening insight into the underlying biology of Alzheimer's disease reveals that p38 MAPK operates in other events related to AD, such as excitotoxicity, synaptic plasticity and tau phosphorylation. Although quantification of behavioural improvements upon p38 MAPK inhibition and in vivo evaluation of p38 MAPK significance to various aspects of AD pathology is still missing, the p38 MAPK is emerging as a new Alzheimer's disease treatment strategy. Thus, we present here an update on the role of p38 MAPK in neurodegeneration, with a focus on Alzheimer's disease, by summarizing recent literature and several key papers from earlier years.

Matrix metalloproteinase inhibition reduces oxidative stress associated with cerebral amyloid angiopathy in vivo in transgenic mice

Cerebral amyloid angiopathy (CAA), characterized by extracellular beta-amyloid peptide (Abeta) deposits in vessel walls, is present in the majority of cases of Alzheimer's disease and is a major cause of hemorrhagic stroke. Although the molecular pathways activated by vascular Abeta are poorly understood, extracellular matrix metalloproteinases (MMP) and Abeta-induced oxidative stress appear to play important roles. We adapted fluorogenic assays for MMP activity and reactive oxygen species generation for use in vivo. Using multiphoton microscopy in APPswe/PS1dE9 and Tg-2576 transgenic mice, we observed strong associations between MMP activation, oxidative stress, and CAA deposition in leptomeningeal vessels. Antioxidant treatment with alpha-phenyl-N-tert-butyl-nitrone reduced oxidative stress associated with CAA (approximately 50% reduction) without affecting MMP activation. Conversely, a selection of agents that inhibit MMP by different mechanisms of action, including minocycline, simvastatin, and GM6001, reduced not only CAA-associated MMP activation (approximately 30-40% reduction) but also oxidative stress (approximately 40% reduction). The inhibitors of MMP did not have direct antioxidant effects. Treatment of animals with alpha-phenyl-N-tert-butyl-nitrone or minocycline did not have a significant effect on CAA progression rates. These data suggest a close association between Abeta-related MMP activation and oxidative stress in vivo and raise the possibility that treatment with MMP inhibitors may have beneficial effects by indirectly reducing the oxidative stress associated with CAA.

Human postmortem brain-derived cerebrovascular smooth muscle cells express all genes of the classical complement pathway: a potential mechanism for vascular damage in cerebral amyloid angiopathy and Alzheimer's disease

Deposition of amyloid around blood vessels, known as cerebral amyloid angiopathy (CAA), is a major pathological feature found in the majority of Alzheimer's disease (AD) cases, and activated complement fragments have been detected on CAA deposits in AD brains. In this study, we demonstrate for the first time that human cerebrovascular smooth muscle cells (HCSMC) isolated from cortical vessels derived from postmortem brains can express mRNAs for complement genes C1qB, C1r, C1s, C2, C3, C4, C5, C6, C7, C8 and C9, the components of the classical complement pathway. Secretion of the corresponding complement proteins for these genes was also demonstrated, except for C1q and C5. Of particular significance was the observation that treatment of HCSMC with aggregated amyloid beta (Abeta) 1-42 increased expression of complement C3 mRNA and increased release of C3 protein. Abeta treatment of HCSMC also increased expression of C6 mRNA. Interferon-gamma induced expression and release of complement C1r, C1s, C2 and C4. As HCSMC are closely associated with Abeta deposits in vessels in the brain, their production of complement proteins could amplify the proinflammatory effects of amyloid in the perivascular environment, further compromising brain vascular integrity.