Seropositivity and reactivations of HSV-1, but not of HSV-2 nor VZV, associate with altered blood-brain barrier, beta amyloid, and tau proteins in people living with HIV.

Among 128 adult people living with HIV and no neurological conditions confounding the cerebrospinal fluid results, the presence of HSV-1 chronic infection (detected either by serology or PCR), but not of HSV-2 and VZV, independently associated with higher odds of blood-brain barrier impairment, abnormally increased cerebrospinal fluid levels of tau and phosphorylated-181 tau, and decreased concentrations of fragments 1-42 of beta amyloid compared to the seronegative counterpart. These associations were even stronger for seropositive participants with a positive history of at least one symptomatic reactivation of HSV-1.

Brain 18 F-Florbetapir PET/CT Findings in an Early-onset Alzheimer Disease Patient Carrying Presenilin-1 G378E Mutation.

Positron emission tomography (PET) with 18 F-Fluorodeoxyglucose ( 18 F-FDG) plays an outstanding role in the diagnostic work-up of dementia. Amyloid PET imaging is a complementary imaging technique for the early detection of Alzheimer disease (AD). ß-amyloid precursor protein ( APP ), Presenilin-1 ( PSEN1 ) and Presenilin-2 ( PSEN2 ) are the 3 main causative genes responsible for autosomal dominant early-onset Alzheimer disease (EOAD). This is the first report of 18 F-Florbetapir amyloid imaging findings in a 35-year-old male patient with EOAD carrying the G378E mutation in PSEN1 gene. Brain computed tomography (CT) and magnetic resonance imaging scans showed remarkable cerebral atrophy with dilatation of the cerebrospinal fluid spaces; furthermore, a 18 F-Florbetapir PET/CT scan demonstrated also widespread remarkable accumulation of the amyloid tracer in the cerebral cortex, with reduction of the normal contrast between white and gray matter and flattening of the external cortical margins. Furthermore, PET/CT showed intense 18 F-florbetapir uptake in the striatum and in the thalamus bilaterally. Our case supports the usefulness of amyloid PET imaging in the diagnostic work-up of EOAD.

Low cerebrospinal fluid Amyloid-ßeta 1-42 in patients with tuberculous meningitis.

BACKGROUND: Tuberculous meningitis (TBM) is an important disease leading to morbidity, disability and mortality that primarily affects children and immune-depressed patients. Specific neuromarkers predicting outcomes, severity and inflammatory response are still lacking. In recent years an increasing number of evidences show a possible role for infective agents in developing neurodegenerative diseases. METHODS: We retrospectively included 13 HIV-negative patients presenting with TBM and we compared them with two control groups: one of patients with a confirmed diagnosis of AD, and one of those with syphilis where lumbar punctures excluded central nervous system involvement. Lumbar punctures were performed for clinical reasons and CSF biomarkers were routinely available: we analyzed blood brain barrier permeability (CSF to serum albumin ratio, "CSAR"), intrathecal IgG synthesis, (CSF to serum IgG ratio), inflammation (neopterin), amyloid deposition (Aß1-42), neuronal damage (T-tau, P-tau, 14.3.3) and astrocytosis (S-100 ß). RESULTS: TBM patients were 83 % male and 67 % Caucasian with a median age of 51 years (24.5-63.5 IQR). Apart from altered CSAR (median value 18.4, 17.1-30.9 IQR), neopterin (14.3 ng/ml, 9.7-18.8) and IgG ratios (15.4, 7.9-24.9), patients showed very low levels of Aß1-42 in their CSF (348.5 pg/mL,125-532.2), even lower compared to AD and controls [603 pg/mL (IQR 528-797) and 978 (IQR 789-1178)]. Protein 14.3.3 tested altered in 38.5 % cases. T-tau, P-tau and S100Beta were in the range of normality. Altered low level of Aß1-42 correlated over time with classical TBM findings and altered neuromarkers. CONCLUSIONS: CSF Biomarkers from patients with TBM were compatible with inflammation, blood brain barrier damage and impairment in amyloid-beta metabolism. Amyloid-beta could be tested as a prognostic markers, backing the routine use of available neuromarkers. To our knowledge this is the first case showing such low levels of Aß1-42 in TBM; its accumulation, drove by neuroinflammation related to infections, can be central in understanding neurodegenerative diseases.

Cerebrospinal fluid biomarkers in patients with central nervous system infections: a retrospective study.

BACKGROUND: Central nervous system (CNS) may be infected by several agents, resulting in different presentations and outcomes. Analysis of cerebrospinal fluid (CSF) markers could be helpful to differentiate specific conditions and setting an appropriate therapy. METHODS: Patients presenting with signs and symptoms were enrolled if, before receiving a diagnostic lumbar puncture, signed a written informed consent. We analyzed CSF indexes of blood-brain barrier permeability (CSF to serum albumin ratio or CSAR), inflammation (CSF to serum IgG ratio, neopterin), amyloid deposition (1-42 ß-amyloid), neuronal damage (Total tau (T-tau), Phosphorylated tau (P-tau), and 14.3.3 protein) and astrocyte damage (S-100ß). RESULTS: Two hundred and eighty-one patients were included: they were mainly affected by herpesvirus encephalitis, enterovirus meningoencephalitis, bacterial meningitis (Neisseria meningitidis and Streptococcus pneumoniae), and infection by other etiological agents or unknown pathogen. Their CSF features were compared with HIV-negative patients and native HIV-positive individuals without CNS involvement. 14.3.3 protein was found in bacterial and HSV infections while T-tau and neopterin were abnormally high in the herpesvirus group. P-tau, instead, was elevated in enterovirus meningitis. S-100ß was found to be high in patients with HSV-1 and HSV-2 infections but not in those with Varicella Zoster Virus (VZV). Thirty-day mortality was unexpectedly low (2.7%): patients who died had higher levels of T-tau and, significantly, lower levels of Aß1-42. CONCLUSION: This work demonstrates that CSF biomarkers of neuronal damage or inflammation may vary during CNS infections according to different causative agents. The prognostic value of these biomarkers needs to be assessed in prospective studies.

A large genomic deletion leads to enhancer adoption by the lamin B1 gene: a second path to autosomal dominant adult-onset demyelinating leukodystrophy (ADLD).

Chromosomal rearrangements with duplication of the lamin B1 (LMNB1) gene underlie autosomal dominant adult-onset demyelinating leukodystrophy (ADLD), a rare neurological disorder in which overexpression of LMNB1 causes progressive central nervous system demyelination. However, we previously reported an ADLD family (ADLD-1-TO) without evidence of duplication or other mutation in LMNB1 despite linkage to the LMNB1 locus and lamin B1 overexpression. By custom array-CGH, we further investigated this family and report here that patients carry a large (∼660 kb) heterozygous deletion that begins 66 kb upstream of the LMNB1 promoter. Lamin B1 overexpression was confirmed in further ADLD-1-TO tissues and in a postmortem brain sample, where lamin B1 was increased in the frontal lobe. Through parallel studies, we investigated both loss of genetic material and chromosomal rearrangement as possible causes of LMNB1 overexpression, and found that ADLD-1-TO plausibly results from an enhancer adoption mechanism. The deletion eliminates a genome topological domain boundary, allowing normally forbidden interactions between at least three forebrain-directed enhancers and the LMNB1 promoter, in line with the observed mainly cerebral localization of lamin B1 overexpression and myelin degeneration. This second route to LMNB1 overexpression and ADLD is a new example of the relevance of regulatory landscape modifications in determining Mendelian phenotypes.

Cerebrospinal Fluid CXCL13 as Candidate Biomarker of Intrathecal Immune Activation, IgG Synthesis and Neurocognitive Impairment in People with HIV.

Plasma C-X-C-motif chemokine ligand-13 (CXCL13) has been linked to disease progression and mortality in people living with HIV (PLWH) and is a candidate target for immune-based strategies for HIV cure. Its role in central nervous system (CNS) of PLWH has not been detailed. We described CSF CXCL13 levels and its potential associations with neurological outcomes. Cross-sectional study enrolling PLWH without confounding for CXCL13 production. Subjects were divided according to CSF HIV-RNA in undetectable (< 20 cp/mL) and viremics. CSF CXCL13, and biomarkers of blood-brain barrier (BBB) impairment, intrathecal synthesis, and immune activation were measured by commercial immunoturbidimetric and ELISA assays. All subjects underwent neurocognitive assessment. Sensitivity analyses were conducted in subjects with intact BBB only. 175 participants were included. Detectable CSF CXCL13 was more common in the viremic (31.4%) compared to the undetectable group (13.5%; OR 2.9 [1.4-6.3], p = 0.006), but median levels did not change (15.8 [8.2-91.0] vs 10.0 [8.1-14.2] pg/mL). In viremics (n = 86), CXCL13 associated with higher CSF HIV-RNA, proteins, neopterin, intrathecal synthesis and BBB permeability. In undetectable participants (n = 89), CXCL13 associated with higher CD4+T-cells count, CD4/CD8 ratio, CSF proteins, neopterin, and intrathecal synthesis. The presence of CXCL13 in the CSF of undetectable participants was associated with increased odds of HIV-associated neurocognitive disorders (58.3% vs 28.6%, p = 0.041). Sensitivity analyses confirmed all these findings. CXCL13 is detectable in the CSF of PLWH that show increased intrathecal IgG synthesis and immune activation. In PLWH with CSF viral suppression, CXCL13 was also associated with neurocognitive impairment.

A Novel PSEN1 Variant Leading to Posterior Cortical Atrophy: A Case Report.

We describe a 52-year-old patient with a progressive visuospatial disorder and apraxia. Neuropsychological assessment, neuroradiological findings, and Alzheimer's disease (AD) core biomarker assay on cerebrospinal fluid led to a diagnosis of posterior cortical atrophy due to AD. We performed a next generation sequencing dementia-gene panel and found the c.1301 C>T p.(Ala434Val) variant in the Presenilin1 (PSEN1) gene. The missense change affects the PAL (Pro433-Ala434-Leu435) motif critical for catalytic activity of the macromolecular γ-secretase complex. Evolutionary and integrated bioinformatic tools predicted a deleterious effect of the variant supporting its role in the AD pathogenesis.

Changes in Cerebrospinal Fluid, Liver and Intima-media-thickness Biomarkers in Patients with HIV-associated Neurocognitive Disorders Randomized to a Less Neurotoxic Treatment Regimen.

The prevalence of neurocognitive impairment in people living with HIV is estimated between 30 and 50%. The pathogenesis of HIV-associated neurocognitive disorders is complex and multifactorial. Aim of the study was to measure the change in CSF biomarkers, Fibroscan and IMT measurements in PLWH with HAND randomized to a less neurotoxic regimen, or continuing their treatment. Adult patients with HAND were screened and enrolled if presenting no major resistance associated mutations, no HIV viral replication, not on efavirenz or darunavir, with R5-tropic HIV and without major confounding conditions. Lumbar puncture, IMT and Fibroscan measurements were performed. After 1:1 randomization to a less neurotoxic regimen consisting of darunavir/cobicistat plus emtricitabine plus maraviroc, or mantaining actual care, tests were repeated after 24 weeks: CSF biomarkes (HIV RNA, tau, p-tau, Beta-amyloid1-42, S100Beta and neopterin) were included. Non-parametric tests (Mann-Whitney and Wilcoxon's) were used. 28 participants completed the study. Male and European ancestry were prevalent; median age was 55 years (51-60). All patients were virally suppressed; median CD4 + count was 626 cell/uL (469-772). Baseline characteristics were similar between the study arms. A significant decrease in CSF p-tau and an increase in CSF neopterin and NFL were observed. We observed a significant reduction in liver stiffness at W24. Despite a small sample size we observed changes in neuromarkers and in hepatic stiffness in patients randomized to the experimental arm. We observed changes in CSF biomarkers (lower phosphorylated-tau and higher neopterin and NFL) that need to be replicated in large cohorts. Subclinical neurotoxicity may be observed in patients with HAND and warrants prospective studies.

Patterns of Cerebrospinal Fluid Alzheimer's Dementia Biomarkers in People Living with HIV: Cross-Sectional Study on Associated Factors According to Viral Control, Neurological Confounders and Neurocognition.

People living with HIV (PLWH) age with an excess burden of comorbidities that may increase the incidence of age-related complications. There is controversy surrounding the hypothesis that HIV can accelerate neurodegeneration and Alzheimer's dementia (AD). We performed a retrospective study to analyze the distribution of cerebrospinal fluid (CSF) AD biomarkers (beta amyloid 1-42 fragment, tau, and phosphorylated tau) in adult PLWH (on cART with undetectable viremia, n = 136, with detectable viremia, n = 121, and with central nervous system CNS disorders regardless of viremia, n = 72) who underwent a lumbar puncture between 2008 to 2018; HIV-negative controls with AD were included (n = 84). Five subjects (1.5%) presented CSF biomarkers that were compatible with AD: one was diagnosed with AD, whereas the others showed HIV encephalitis, multiple sclerosis, cryptococcal meningitis, and neurotoxoplasmosis. Regardless of confounders, 79.6% of study participants presented normal CSF AD biomarkers. Isolated abnormalities in CSF beta amyloid 1-42 (7.9%) and tau (10.9%) were associated with age, biomarkers of intrathecal injury, and inflammation, although no HIV-specific feature was associated with abnormal CSF patterns. CSF levels of AD biomarkers very poorly overlapped between HIV-positive clinical categories and AD controls. Despite the correlations with neurocognitive performance, the inter-relationship between amyloid and tau proteins in PLWH seem to differ from that observed in AD subjects; the main driver of the isolated increase in tau seems represented by non-specific CNS inflammation, whereas the mechanisms underlying isolated amyloid consumption remain unclear.

Blood-Brain Barrier Impairment in Patients Living with HIV: Predictors and Associated Biomarkers.

Despite the substantial changes resulting from the introduction of combination antiretroviral therapy (cART), the prevalence of HIV-associated neurocognitive disorders (HAND) remains substantial. Blood-brain barrier impairment (BBBi) is a frequent feature in people living with HIV (PLWH) and it may persist despite effective antiretroviral treatment. A cross-sectional study was performed in PLWH who underwent lumbar puncture for clinical reasons or research protocols and several cerebrospinal fluid biomarkers were studied. BBBi was defined as cerebrospinal fluid-to-serum albumin ratio (CSAR) >6.5 (<40 years) or >8 (>40 years). We included 464 participants: 147 cART-naïve and 317 on cART. Male sex was prevalent in both groups (72.1% and 72.2% respectively); median age was 44 (38-52) years in naïve and 49 (43-57) years in treated subjects. BBBi was observed in 35.4% naïve and in 22.7% treated participants; the use of integrase inhibitors was associated with a lower prevalence (18.3 vs. 30.9%, p = 0.050). At multivariate binary logistic regression (including age and sex) nadir CD4 cell count (p = 0.034), presence of central nervous system (CNS) opportunistic infections (p = 0.024) and cerebrospinal fluid (CSF) HIV RNA (p = 0.002) in naïve participants and male sex (p = 0.021), a history of CNS opportunistic infections (p = 0.001) and CSF HIV RNA (p = 0.034) in treated patients were independently associated with BBBi. CSF cells and neopterin were significantly higher in participants with BBBi. BBBi was prevalent in naïve and treated PLWH and it was associated with CSF HIV RNA and neopterin. Systemic control of viral replication seems to be essential for BBB integrity while sex and treatment influence need further studies.

Alzheimer Dementia in People Living With HIV.

OBJECTIVE: Given the aging of people living with HIV (PLWH) and the high prevalence of HIV-associated neurocognitive disorders, we aimed at describing the clinical, instrumental, and CSF features of PLWH diagnosed with Alzheimer dementia (AD). METHODS: The databases of 3 large Italian outpatient clinics taking care of more than 9,000 PLWH were searched for the diagnosis of AD. After obtaining patients' or their next of kin's consent for publication, anonymous data were collected in an excel spreadsheet and described. Routinely collected CSF biomarkers and radiologic imaging results were recorded whether available. RESULTS: Four patients were included in this case series who were diagnosed with AD aged between 60 and 74 years. All participants were on highly active antiretroviral therapy and showed nondetectable serum HIV RNA. Memory impairment was the most prominent cognitive feature. The diagnosis was obtained considering the exclusion of other potential causes, MRI and fluorodeoxyglucose-PET features, and, in (in 2/4), CSF AD biomarkers levels. In 1 patient, longitudinal CSF tau/p-tau increased, and beta-amyloid1-42 decreased over time despite antiretroviral therapy containing nucleotide reverse transcriptase inhibitors. CONCLUSIONS: In older PLWH cognitive symptoms may represent the onset of AD: a multidisciplinary team may be needed for reaching a likely in vivo diagnosis.

Dual antiretroviral therapies are effective and safe regimens in the central nervous system of neurologically symptomatic people living with HIV.

OBJECTIVE: Aim of this study was to compare cerebrospinal fluid (CSF) virological control, biomarkers and neurocognition of neurologically symptomatic patients on dual antiretroviral therapies (dual therapy) vs. 2 nucleoside reverse transcriptase inhibitors-based three-drug regimens (triple therapy). DESIGN: Retrospective monocentric cross-sectional study. METHODS: We analysed data from people living with HIV undergoing lumbar puncture for clinical/research reasons with plasma HIV-RNA less than 200 copies/ml and neurological/neurocognitive symptoms without significant contributing comorbidities. We measured CSF HIV-RNA, inflammation, blood-brain barrier integrity, neuronal damage and astrocytosis biomarkers (five biomarkers by ELISA and five indices by immunoturbidimetry) and recorded the neurocognitive performance (14 tests). CSF escape was defined as any case of CSF HIV-RNA 0.5 Log10 higher than viraemia or any case of detectable CSF HIV-RNA coupled with undetectable viraemia. RESULTS: A total of 78 patients on triple therapy and 19 on dual therapy were included. Overall, 75.3% male, median age 51 years (46-58), current CD4 count 545 cells/µl (349-735), time on current regimens 18 months (8-29), but length of plasma suppression 32 months (14-94). The two groups did not differ in terms of HIV-associated neurological diagnoses, demographic and viro-immunological features. Undetectable CSF HIV-RNA (73.7% in dual therapy vs. 78.2% in triple therapy, p.67) and CSF escape (21.1% in dual therapy vs. 19.2% in triple therapy, p.86) did not differ. No difference was observed in depression, anxiety, neurocognition (in 63 participants) nor in any tested biomarker. CONCLUSION: In people living with HIV with neurological/neurocognitive symptoms, peripherally effective dual therapy can show CSF virosuppression, inflammation, neuronal and astrocyte integrity and neurocognition comparable to triple therapy.

Presence of Epstein-Barr virus DNA in cerebrospinal fluid is associated with greater HIV RNA and inflammation.

OBJECTIVE: The current study aimed to investigate whether cerebrospinal fluid (CSF) Epstein-Barr virus (EBV) or cytomegalovirus (CMV) DNA was associated with viral, inflammatory and neuronal damage biomarkers in people living with HIV (PLWH). DESIGN: A cross-sectional diagnostic study on CSF fluid samples in patients undergoing lumbar punctures for clinical reasons, to better understand the role of EBV and CMV in the CNS on HIV RNA replication, blood-brain-barrier (BBB) damage and biomarkers of neuronal damage/inflammation. METHODS: EBV, CMV DNA and HIV RNA were measured on CSF, through real time (RT)-PCR, from PLWHs undergoing lumbar punctures for clinical reasons (excluding oncho-haematological comorbidities). Immune-enzymatic assays evaluated blood-brain barrier inflammation and damage. Patients were stratified according to plasma HIV RNA levels in viremic (≥50 copies/ml) and aviremic (<50 copies/ml). RESULTS: We included 297 participants. Among 167 viremic patients CSF EBV and CMV DNA were detectable in 42 (25.1%) and 10 (6.3%) participants; among 130 aviremic individuals CSF EBV and CMV DNA were detectable in 12 (9.2%) and 0 (0%) participants, respectively. In viremic group detectable CSF EBV DNA was associated with CSF pleocytosis (P < 0.001), higher CSF HIV RNA (P < 0.001) and neopterin levels (P = 0.002). In aviremic participants detectable EBV DNA was associated with pleocytosis (P = 0.056), higher neopterin (P = 0.027) and immune globulins (P = 0.016) in the CSF; CSF escape was more common in those with detectable EBV DNA (50 vs. 21.2%, P = 0.036). CONCLUSION: EBV DNA was frequently detected in the CSF of viremic and fewer aviremic patients on antiretroviral treatment. In PLWH without clinical evidence of encephalitis CSF EBV DNA was associated with higher biomarkers levels of neuronal damage/inflammation. The role of EBV reactivation in HIV-associated central nervous system disorders warrants further studies.

Clinical and neuropathological phenotype associated with the novel V189I mutation in the prion protein gene.

Prion diseases are neurodegenerative disorders which are caused by an accumulation of the abnormal, misfolded prion protein known as scrapie prion protein (PrPSc). These disorders are unique as they occur as sporadic, genetic and acquired forms. Sporadic Creutzfeldt-Jakob Disease (CJD) is the most common human prion disease, accounting for approximately 85-90% of cases, whereas autosomal dominant genetic forms, due to mutations in the prion protein gene (PRNP), account for 10-15% of cases. Genetic forms show a striking variability in their clinical and neuropathological picture and can sometimes mimic other neurodegenerative diseases.We report a novel PRNP mutation (V189I) in four CJD patients from three unrelated pedigrees. In three patients, the clinical features were typical for CJD and the diagnosis was pathologically confirmed, while the fourth patient presented with a complex phenotype including rapidly progressive dementia, behavioral abnormalities, ataxia and extrapyramidal features, and the diagnosis was probable CJD by current criteria, on the basis of PrPSc detection in CSF by Real Time Quaking-Induced Conversion assay. In all the three patients with autopsy findings, the neuropathological analysis revealed diffuse synaptic type deposition of proteinase K-resistant prion protein (PrPres), and type 1 PrPres was identified in the brain by western blot analysis. So, the histopathological and biochemical profile associated with the V189I mutation was indistinguishable from the MM1/MV1 subtype of sporadic CJD.Our findings support a pathogenic role for the V189I PRNP variant, confirm the heterogeneity of the clinical phenotypes associated to PRNP mutations and highlight the importance of PrPSc detection assays as diagnostic tools to unveil prion diseases presenting with atypical phenotypes.

A previously undiagnosed case of Gerstmann-Sträussler-Scheinker disease revealed by PRNP gene analysis in patients with adult-onset ataxia.

Ataxia is a frequently reported symptom in prion diseases (PD) and it is characteristic of Gerstmann-Sträussler-Scheinker syndrome (GSS), a genetic PD mainly related to the P102L mutation in the PRNP gene. Our aim was to screen for the P102L and other six known PRNP gene mutations (P105L, A117V, Y145X, E200K, D202N, and V210I) a group of 206 consecutive patients diagnosed with adult-onset cerebellar ataxia of unknown origin. The patients, negative for the most common acquired and genetic forms, were analyzed using a combination of restriction endonuclease digestion and pyrosequencing; eight, affected by ataxia and cognitive dysfunction, were also sequenced for the PRNP gene. One patient resulted to be heterozygous for the P102L mutation. Retrospectively, the clinical picture was consistent with a "classical" GSS phenotype. In conclusion, the screening for the P102L mutation, or even the sequencing of the PRNP gene should be taken in consideration in patients with late-onset ataxia (>50 years).

Novel GRN Mutations in Alzheimer's Disease and Frontotemporal Lobar Degeneration.

BACKGROUND: During the twentieth century, frontotemporal dementia (FTD) was often misdiagnosed, confused with Alzheimer's disease or psychiatric disorders, jeopardizing care and research. OBJECTIVE: To analyze the FTD genes in the DNA samples of patients belonging to families clinically classified as probable Alzheimer's disease (FAD) in the early 1990s and not carrying mutation in the three main genes linked to FAD (Presenilin 1, Presenilin 2, and Amyloid precursor protein). METHODS: The genetic screening was performed on 63 probands diagnosed as FAD before the early 2000s. RESULTS: Four patients out of the 63 studied (4/63, 6.3%) resulted as carrying four different GRN genetic variations: p.T272SfsX10, p.R110X, p.C149LfsX10, and p.W304C. The first two mutations (p.T272SfsX10, p.R110X) are the most frequent ones in Italy in FTD patients; the latter two (p.C149LfsX10 and p.W304C) are not described in the scientific literature. CONCLUSION: Our data suggest that it can be important to re-examine FAD patients diagnosed when the FTD spectrum was not well recognized and the causative FTD genes had not yet been identified. Moreover, we propose initially analyzing genes associated with the first form of suspected dementia and, if the results are negative, studying genes implicated in the other form of dementia.

Lack of caspase-dependent apoptosis in spinal motor neurons of the wobbler mouse.

The mechanism of motor neuron degeneration in amyotrophic lateral sclerosis (ALS) is still unclear and the post-mortem analysis of samples from ALS patients does not permit a clarification of the early events of cell death occurring in ALS. Animal models of motor neuron degeneration represent a reliable tool to investigate the type of cell death. Attention was focused on the possible role of apoptosis in a spontaneous model of cervical spinal cord motor neuron degeneration, the wobbler mouse. Firstly, the rate of motor neuron loss occurring in the cervical spinal cord region of wobbler mice during different phases of symptoms progression was quantified by CholineAcetyltransferase (ChAT) immunohistochemistry. This was followed by a series of immunohistological studies to ascertain whether apoptosis was actually involved. ChAT immunostaining confirmed the severe loss of cholinergic neurons. Since the rate of motor neuron death is maximal in the first phase of the disease (from the 3rd to the 5th postnatal week), apoptotic markers were evaluated in 4-week-old wobbler mice. This study, carried out by examining a large number of cervical spinal cord sections from 20 affected animals and 20 healthy littermates, did not show either caspase activation or DNA fragmentation. These results strongly suggest that motor neuron death occurring in the wobbler mouse is not related to a caspase-dependent apoptotic mechanism.

Clearance of cerebrospinal fluid JCV DNA with mirtazapine in a patient with progressive multifocal leukoencephalopathy and sarcoidosis.

Progressive multifocal leukoencephalopathy (PML) is a severe encephalic demyelinating disease associated with JC virus (JCV) reactivation that occurs mostly in patients with immune disorders. Patients affected by sarcoidosis are at risk for developing PML both for leukocyte dysfunction and for receiving immunosuppressive medications: delayed diagnosis and high-dose corticosteroids are associated with a reduced survival. Although no specific treatment for PML exists, several therapeutic possibilities have been assessed with uncertain benefits (5HT2a receptor inhibitors are active in vitro against JCV): the cornerstone of sarcoidosis-associated PML is immunosuppressants withdrawal.We report the case of a female patient affected by systemic sarcoidosis for 30 years receiving low-dose corticosteroids (5 mg every other day). Due to memory impairment an MRI was performed showing three T2 hyperintense lesions involving white matter. Cerebrospinal fluid JCV PCR (845 copies/ml), neuropathological examination and immunohistochemistry (SV40 protein and JCV DNA positivity) on brain biopsy confirmed PML. Mirtazapine 15 mg was started while prednisone treatment was continued. 3 and 6 months later cognitive performances improved and brain MRIs were stable while cerebrospinal fluid JCV DNA was undetectable (6 months later). In conclusion the diagnosis of PML in patients with sarcoidosis is challenging given the overlapping presentation; the use of 5HT2a receptor antagonists deserves further studying in patients needing immunosuppressant drugs to control their dysimmune disease.

Abundant tau filaments and nonapoptotic neurodegeneration in transgenic mice expressing human P301S tau protein.

The identification of mutations in the Tau gene in frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17) has made it possible to express human tau protein with pathogenic mutations in transgenic animals. Here we report on the production and characterization of a line of mice transgenic for the 383 aa isoform of human tau with the P301S mutation. At 5-6 months of age, homozygous animals from this line developed a neurological phenotype dominated by a severe paraparesis. According to light microscopy, many nerve cells in brain and spinal cord were strongly immunoreactive for hyperphosphorylated tau. According to electron microscopy, abundant filaments made of hyperphosphorylated tau protein were present. The majority of filaments resembled the half-twisted ribbons described previously in cases of FTDP-17, with a minority of filaments resembling the paired helical filaments of Alzheimer's disease. Sarkosyl-insoluble tau from brains and spinal cords of transgenic mice ran as a hyperphosphorylated 64 kDa band, the same apparent molecular mass as that of the 383 aa tau isoform in the human tauopathies. Perchloric acid-soluble tau was also phosphorylated at many sites, with the notable exception of serine 214. In the spinal cord, neurodegeneration was present, as indicated by a 49% reduction in the number of motor neurons. No evidence for apoptosis was obtained, despite the extensive colocalization of hyperphosphorylated tau protein with activated MAP kinase family members. The latter may be involved in the hyperphosphorylation of tau.