Acute and chronic synaptic pathology in multiple sclerosis gray matter.

OBJECTIVES: To investigate the extent of synaptic loss, and the contribution of gray matter (GM) inflammation and demyelination to synaptic loss, in multiple sclerosis (MS) brain tissue. METHODS: This study was performed on two different post-mortem series of MS and control brains, including deep GM and cortical GM. MS brain samples had been specifically selected for the presence of active demyelinating GM lesions. Over 1,000,000 individual synapses were identified and counted using confocal microscopy, and further characterized as glutamatergic/GABAergic. Synaptic counts were also correlated with neuronal/axonal loss. RESULTS: Important synaptic loss was observed in active demyelinating GM lesions (-58.9%), while in chronic inactive GM lesions, synaptic density was only mildly reduced compared to adjacent non-lesional gray matter (NLGM) (-12.6%). Synaptic loss equally affected glutamatergic and GABAergic synapses. Diffuse synaptic loss was observed in MS NLGM compared to control GM (-21.2% overall). CONCLUSION: This study provides evidence, in MS brain tissue, of acute synaptic damage/loss during active GM inflammatory demyelination and of synaptic reorganization in chronically demyelinated GM, affecting equally glutamatergic and GABAergic synapses. Furthermore, this study provides a strong indication of widespread synaptic loss in MS NLGM also independently from focal GM demyelination.

Subclinical hypothyroidism is associated with migraine: A case-control study.

BACKGROUND: Recent studies suggested a potential association between both overt and subclinical hypothyroidism and migraine. Aims of this study were to estimate the comorbidity of migraine in patients with subclinical hypothyroidism and to evaluate associated clinical characteristics. METHODS: Using a case-control strategy, 151 consecutive subclinical hypothyroidism patients (mean age 48.36 ± 15.86 years) and 150 controls (mean age 50.86 ± 9.19 years) were recruited. In all subjects, migraine characteristics were collected through a direct interview. Clinical and biochemical parameters (thyroid-stimulating hormone, free triiodothyronine, free thyroxine, and anti-thyroid antibodies) were compared between subclinical hypothyroidism patients in comorbidity with migraine and subclinical hypothyroidism patients without migraine. RESULTS: The prevalence of lifetime migraine was significantly higher in subclinical hypothyroidism patients in comparison with controls (46% vs. 13%, p < 0.001; OR 5.80; 95% CI = 3.35-10.34). Both migraine without and with aura were significantly higher in subclinical hypothyroidism patients than controls ( p < 0.001 and p = 0.010, respectively). Thyroid hormones and concentrations of antibodies did not differ between subclinical hypothyroidism patients with and without migraine. Interestingly, a comorbidity for autoimmune diseases was observed in subclinical hypothyroidism patients with migraine in respect to those without migraine ( p = 0.005). CONCLUSIONS: Our data suggest that migraine is more frequent in patients with subclinical hypothyroidism in respect to controls. Further studies are needed in order to confirm this association.

Overexpression of sphingosine-1-phosphate receptors on reactive astrocytes drives neuropathology of multiple sclerosis rebound after fingolimod discontinuation.

We present the neuropathological description of an autoptic case of fatal rebound of disease activity after fingolimod discontinuation in a multiple sclerosis patient. MRI prior to the fatal outcome showed several large tumefactive demyelinating lesions. These lesions were characterized by prominent astrocytic gliosis, with a remarkable preponderance of large hypertrophic reactive astrocytes showing intense expression of sphingosine-1-phosphate receptor 1. Prominent astrocytic gliosis was also diffusely observed in the normal-appearing white matter. Dysregulated sphingosine-1-phosphate signaling on astrocytes following fingolimod withdrawal might represent a possible contributing mechanism to disease rebound and might account for the unusual radiological and neuropathological features observed in the present case.

Verapamil Inhibits Ser202/Thr205 Phosphorylation of Tau by Blocking TXNIP/ROS/p38 MAPK Pathway.

PURPOSE: Oxidative stress is a hallmark of Alzheimer's Disease (AD) and promotes tau phosphorylation. Since Thioredoxin Interacting protein (TXNIP), the inhibitor of the anti-oxidant system of Thioredoxin, is up regulated in the hippocampus of AD patients, we investigated whether TXNIP plays a role in promoting tau phosphorylation and whether Verapamil, an inhibitor of TXNIP expression, prevents TXNIP downstream effects. METHODS: We analyzed TXNIP expression and tau phosphorylation in the hippocampus of the 5xFAD mice in the absence and presence of a pharmacological treatment with Verapamil. Using SH-SY5Y cells, we verified the causative role of TXNIP in promoting tau phosphorylation at Ser202/Thr205, by inducing TXNIP silencing. RESULTS: The amyloid beta peptide (Aß1-42) leads to TXNIP over-expression in SH-SY5Y cells, which in turns induces oxidative stress and the activation of p38 MAPK, promoting tau phosphorylation at Ser202/Thr205. Silencing of TXNIP abolishes Aß1-42-induced tau phosphorylation, p38 MAPK phosphorylation and subsequent tau phosphorylation. Verapamil prevents TXNIP expression as well as p38 MAPK and tau phosphorylation at Ser202/Thr205 in the hippocampus of the 5xFAD mice. CONCLUSIONS: Our study unveil a novel pathway involved in AD progression that is inhibited by Verapamil, shedding new light on the understanding of the therapeutic potential of Verapamil in AD.

Amyotrophic Lateral Sclerosis, a Multisystem Pathology: Insights into the Role of TNFα.

Amyotrophic lateral sclerosis (ALS) is considered a multifactorial, multisystem disease in which inflammation and the immune system play important roles in development and progression. The pleiotropic cytokine TNFα is one of the major players governing the inflammation in the central nervous system and peripheral districts such as the neuromuscular and immune system. Changes in TNFα levels are reported in blood, cerebrospinal fluid, and nerve tissues of ALS patients and animal models. However, whether they play a detrimental or protective role on the disease progression is still not clear. Our group and others have recently reported opposite involvements of TNFR1 and TNFR2 in motor neuron death. TNFR2 mediates TNFα toxic effects on these neurons presumably through the activation of MAP kinase-related pathways. On the other hand, TNFR2 regulates the function and proliferation of regulatory T cells (Treg) whose expression is inversely correlated with the disease progression rate in ALS patients. In addition, TNFα is considered a procachectic factor with a direct catabolic effect on skeletal muscles, causing wasting. We review and discuss the role of TNFα in ALS in the light of its multisystem nature.

Chronic acquired hepatocerebral degeneration, pallidal T1 MRI hyperintensity and manganese in a series of cirrhotic patients.

Chronic acquired hepatocerebral degeneration (CAHD) is a rare neurological disorder of cirrhotic patients, characterized by parkinsonism and cognitive impairment. A T1 hyperintensity on the globus pallidum due to an accumulation of manganese (Mn) is found in these patients. The aim of the study was to investigate CAHD, Mn and the MRI pallidal signal in a series of cirrhotic patients. The association between pallidal T1 hyperintensity, CAHD, and blood levels of Mn, the effect of orthotopic liver transplantation (OLT) on the MRI signal and neurological findings, and the role of the pallidal signal as a predictor of CAHD were evaluated. Twenty-six out of 90 patients with cirrhosis had pallidal T1 hyperintensity. Seven patients had CAHD. OLT was followed by the disappearance of CAHD and MRI signal in 2/2 patients. The MRI signal disappeared after OLT in 8/13 patients after a median follow-up time of 24 months. In the patients who did not undergo OLT, CAHD did not present after a median follow-up time of 18 months. The cause of cirrhosis, episodes of acute hepatic encephalopathy and signal intensity were not correlated with CAHD. The blood levels of Mn did not reflect either the MRI signal or CAHD. In conclusion, the pallidal T1 hyperintensity is a prerequisite for the clinical manifestations of CAHD but is not sufficient. The blood levels of Mn as routinely monitored are not a useful marker of Mn burden. The MRI pallidal signal is not a predictor of CAHD.

Cytoplasmic accumulation of TDP-43 in circulating lymphomonocytes of ALS patients with and without TARDBP mutations.

TDP-43, encoded by TARDBP, is a ubiquitously expressed, primarily nuclear protein. In recent years, TDP-43 has been identified as the major pathological protein in ALS due to its mislocalisation in the cytoplasm of motor neurons of patients with and without TARDBP mutations and expression in forms that do not match its predicted molecular weight. In this study, the TDP-43 profile was investigated using western immunoblot analysis in whole lysates, nuclei and cytoplasm of circulating lymphomonocytes from 16 ALS patients, 4 with (ALS/TDP+) and 12 without (ALS/TDP-) TARDBP mutations in the protein C-terminal domain, and thirteen age-matched, healthy donors (controls). Three disease-unaffected first-degree relatives of an ALS/TDP+ patient were also included: one carried the parent mutation (Rel/TDP+) whereas the other two did not (Rel/TDP-). In all ALS patients, relatives and controls, TDP-43 retained the predicted molecular weight in whole cell lysates and nuclei, but in the cytoplasm its molecular weight was slightly smaller than expected. In quantitative terms, TDP-43 was expressed at approximately the same levels in whole cell lysates of ALS patients, relatives and controls. In contrast, TDP-43 accumulated in the cytoplasm with concomitant nuclear depletion in all ALS/TDP+ patients, in about 50% of ALS/TDP- patients and in the Rel/TDP+ subject compared to the controls. In the remaining ALS/TDP- patients and in the two Rel/TDP- subjects, TDP-43 matched the control levels in both subcellular compartments. Were these findings further confirmed, circulating lymphomonocytes could be informative of TDP-43 mislocalisation in nervous tissue and used as a biomarker for future disease risk.

Progranulin expression in brain tissue and cerebrospinal fluid levels in multiple sclerosis.

BACKGROUND: Progranulin (PGRN) is a fundamental neurotrophic factor, and is also involved in inflammation and wound repair. PGRN may have pro- or anti-inflammatory properties, depending upon proteolysis of the anti-inflammatory parent PGRN protein and the generation of pro-inflammatory granulin peptides. OBJECTIVES: Our objectives were as follows: (1) to evaluate the presence and distribution of PGRN in multiple sclerosis (MS) brain tissue, correlating it with demyelination and inflammation; (2) to evaluate cerebrospinal fluid (CSF) PGRN concentrations in patients with MS and controls, in relationship to the clinical features of the disease. METHODS: Our study involved the following: (1) neuropathological study of PGRN on post-mortem tissue of 19 MS and six control brains; (2) evaluation of PGRN CSF concentration in 40 MS patients, 15 non-inflammatory controls and five inflammatory controls (viral encephalitis). RESULTS: In active demyelinating lesions, PGRN was expressed on macrophages/microglia. In the normal-appearing white matter (NAWM), expression of PGRN was observed on activated microglia. PGRN was expressed by neurons and microglia in cortical lesions and in normal-appearing cortex. No expression of PGRN was observed in controls, except on neurons. PGRN CSF concentrations were significantly higher in patients with relapsing-remitting MS during relapses and in progressive MS patients, compared with relapsing-remitting MS patients during remissions and with non-inflammatory controls. CONCLUSIONS: PGRN is strongly expressed in MS brains, by macrophages/microglia in active lesions, and by activated microglia in the NAWM; PGRN CSF concentrations in MS are correspondingly increased in conditions of enhanced macrophage/microglia activation, such as during relapses and in progressive MS.

Dementia and cognitive impairment in amyotrophic lateral sclerosis: a review.

Amyotrophic lateral sclerosis (ALS) is generally considered to be a paradigm of pure motor neuron disorder; nevertheless, the possible occurrence of cognitive impairment up to a frank dementia in patients affected by ALS is recognized. The appraisal of the cognitive impairment in ALS patients is crucial not only to the therapeutic trials of this incurable disease, but also to the planning of care, compliance to interventions, the end-of-life decisions. The cognitive/behavioral changes of ALS patients are consistent with frontotemporal dysfunctions; the overlap of neuropathological features of ALS and frontotemporal lobe degeneration (FTLD) supports, in addition, the putative spectrum of ALS and FTD. In the present review, the pertinent clinical, genetic, neuropathological, neuropsychological and neuroimaging data of the literature are comprehensively and critically discussed. The distinct and overlapping features of ALS and FTD are pointed out, as well as the undisclosed questions deserving additional studies.

Demyelination, inflammation, and neurodegeneration in multiple sclerosis deep gray matter.

Gray matter (GM) lesions are recognized as important components of the pathology of multiple sclerosis (MS), and involvement of the deep gray matter (DGM) is suggested by magnetic resonance imaging. The aims of this study were to determine the frequency and distribution of lesions and characterize the inflammatory and neurodegenerative changes in DGM of MS patients. Histochemistry, immunohistochemistry, and morphometry were performed on whole coronal sections of 14 MS and 12 control (6 normal, 6 from amyotrophic lateral sclerosis patients) brains. Demyelinating lesions were frequent in MS DGM; most often in the thalamus and caudate, but they were also seen in the putamen, pallidum, claustrum, amygdala, hypothalamus, and substantia nigra. Most DGM lesions involved both GM and white matter. Inflammation in active DGM lesions was similar to that in lesions only in white matter but was less intense, and there was a preponderance of activated microglia, scarce myelin-laden macrophages, and a lesser extent of axonal damage. Neuronal loss was observed both in DGM lesions and nondemyelinated DGM with neuron atrophy in nondemyelinated DGM. In conclusion, demyelination and neurodegenerative changes are common in MS DGM and may contribute to clinical impairment. Inflammation in DGM lesions is intermediate between the destructive inflammation of white matter lesions and the minimal inflammation of cortical lesions. We hypothesize that alterations of glutamate reuptake mechanisms may contribute to these differences.

Alterations of myelin-specific proteins and sphingolipids characterize the brains of acid sphingomyelinase-deficient mice, an animal model of Niemann-Pick disease type A.

Niemann-Pick disease (NPD) type A is a neurodegenerative disorder caused by sphingomyelin (SM) accumulation in lysosomes relying on reduced or absent acid sphingomyelinase (ASM) activity. NPD-A patients develop progressive neurodegeneration including cerebral and cerebellar atrophy, relevant Purkinje cell and myelin deficiency with death within 3 years. ASM'knock-out' (ASMKO) mice, an animal model of NPD-A, develop a phenotype largely mimicking that of NPD-A. The mechanisms underlying myelin formation are poorly documented in ASMKO mice. In this study we determined the content of four myelin-specific proteins, myelin basic protein (MBP), 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP), myelin associated glycoprotein (MAG) and proteolipid protein (PLP), and that of myelin-enriched sphingolipids in the brains of ASMKO and wild-type mice in early stages of post-natal (pn) life. Protein and mRNA analysis revealed that in ASMKO mice beginning from 4 post-natal weeks (wk-pn), the expression levels of MAG, CNP, and MBP were below those observed in wild-type mice and the same applied to PLP at 10 wk-pn. Moreover, at 4 wk-pn the expression of SOX10, one of the transcription factors involved in oligodendrocyte development and maintenance was lower in ASMKO mice. Lipid analysis showed that SM and the gangliosides GM3 and GM2 accumulated in the brains of ASMKO mice, as opposed to galactocerebroside and galactosulfocerebroside that, in parallel with the mRNAs of UDP-galactose ceramide galactosyltransferase and galactose-3-O-sulfotransferase 1, the two transferases involved in their synthesis, decreased. Myelin lipid analysis showed a progressive sphingomyelin accumulation in ASMKO mice; noteworthy, of the two sphingomyelin species known to be resolved by TLC, only that with the lower Rf accumulated. The immunohistochemical analysis showed that the reduced expression of myelin specific proteins in ASMKO mice at 10 wk-pn was not restricted to the Purkinje layer of the cerebellar cortex but involved the cerebral cortex as well. In conclusion, reduced oligodendrocyte metabolic activity is likely to be the chief cause of myelin deficiency in ASMKO mice, thus shedding light on the molecular dysfunctions underlying neurodegeneration in NPD-A.

Absence of TARDBP gene mutations in an italian series of patients with frontotemporal lobar degeneration.

BACKGROUND/AIM: Recent studies showed that TAR DNA-binding protein 43 (TDP-43), encoded by the TARDBP gene, is a major pathological protein in both sporadic and familial frontotemporal lobar degeneration (FTLD). The aim of this study was to search for mutations of the TARDBP gene in the disease. METHODS: We sequenced the TARDBP gene in 172 unrelated FTLD patients recruited from 2 Italian memory clinics. RESULTS: We identified 3 different variants of the TARDBP gene in 12 FTLD patients. Three patients showed a silent variant, Ala66Ala (c.332T --> C) in exon 2. A novel heterozygous mutation was found in intron 4 (c.543 + 51A --> G) in 1 patient, which is not located at the splicing site. Finally, a c.208C --> T variant in the 3' untranslated region was detected in 8 probands. None of the aforementioned variants were predicted to affect TDP-43. Hence, pathogenic mutations were not identified in any of the FTLD cases. CONCLUSION: Our study, in accord with previous studies in different populations, found no evidence for a major genetic role of the TARDBP gene in FTLD.

High Risk of Suicide in Behavioral Variant Frontotemporal Dementia.

AIM: The purpose of the study was to determine the prevalence of suicidal ideation and attempts in patients with behavioral variant frontotemporal dementia (bvFTD), evaluating possible risk factors for suicidality. METHODS: Risk of suicide was assessed using the Scale for Suicide Ideation (SSI) in 35 patients with bvFTD and 25 controls. RESULTS: According to SSI, 40% of patients with bvFTD had suicidal ideation in comparison to 8% of controls ( P = .009). Four patients with bvFTD have attempted suicide versus none control ( P = .006). Patients with bvFTD with suicide risk showed higher levels of anxiety, depression, stress, and hopelessness than patients without suicide risk ( P < .001). Patients who attempted suicide were younger and had a longer disease duration than those with only suicide ideation. Intriguingly, 40% of patients with parkinsonism presented high level of suicide ideation. CONCLUSIONS: Our findings show that patients with bvFTD have a high risk of suicide. Additional studies in larger populations are needed to confirm our results.

ATXN2 intermediate repeat expansions influence the clinical phenotype in frontotemporal dementia.

Common genetic risk factors are associated with frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). Intermediate repeat expansions at the Ataxin-2 locus (ATXN2) are a risk factor for ALS and influence the phenotype. We assessed whether ATXN2 is a risk factor for FTD or modify clinical features in a data set of Italian patients. Three hundred sixty-eight unrelated FTD cases and 342 controls were enrolled. The frequency of intermediate CAG repeats in ATXN2 gene was not different comparing patients and controls. CAG repeats were interrupted by CAA in all patients carrying intermediate repeats. Interestingly, patients with an increased number of CAG repeats had an earlier onset of the disease than those without expansions (p = 0.011), and presented more frequently with parkinsonism (p = 0.010), and psychotic symptoms (p = 0.013) at disease onset. Our study does not support a major role of ATXN2 intermediate CAG expansions in predisposing to FTD but suggests that ATXN2 may act as a phenotype modifier.

Involvement of the choroid plexus in multiple sclerosis autoimmune inflammation: a neuropathological study.

An immunological function has been proposed for the choroid plexus (CP). In multiple sclerosis (MS) brains, CPs show (immunohistochemistry to HLA-DR, CD3, CD20, CD68, VCAM-1, CD138) T lymphocytes in vessels and stroma, VCAM-1 expression on endothelia, intense HLA-DR immunostaining on cells in CP stroma, among CP epithelium and on epiplexus cells. CPs in control or amyotrophic lateral sclerosis brains do not show such inflammatory changes. Intense CP inflammation is observed in viral encephalitis. Changes in MS CPs suggest persisting immune activation, with intensity similar to acute encephalitis, even in MS phases in which neurodegeneration prevails. In MS, CPs could represent a site for lymphocyte entry in the CSF and for CSF antigens presentation.

Mutation analysis of CHCHD2 and CHCHD10 in Italian patients with mitochondrial myopathy.

Mutations in CHCHD2 and CHCHD10 were recently reported in a broad spectrum of neurodegenerative diseases, for example, Parkinson's disease, amyotrophic lateral sclerosis, frontotemporal dementia, or mitochondrial myopathy (MM). The aim of the study was to evaluate the prevalence of CHCHD2 and CHCHD10 mutations in Italian MM patients without mitochondrial DNA mutations. The coding regions of CHCHD2 and CHCHD10 were sequenced in 62 MM patients. None of the patients showed CHCHD2 mutations, whereas 1 sporadic MM patient carried a homozygous Pro96Thr substitution in CHCHD10. Muscle biopsy of this patient showed intracellular glycogen accumulation with cytochrome c oxidase negative and ragged red fibers. Our study suggests that the homozygous Pro96Thr mutation in CHCHD10 might be pathogenic but does not support a major role for CHCHD2 in MM pathogenesis.

Altered glutamate reuptake in relapsing-remitting and secondary progressive multiple sclerosis cortex: correlation with microglia infiltration, demyelination, and neuronal and synaptic damage.

Cortical involvement in multiple sclerosis (MS) is emerging as an important determinant of disease progression. The mechanisms responsible for MS cortical pathology are not fully characterized. The objective of this study was to assess the role of excitotoxicity in MS cortex, evaluating excitatory amino acid transporter (EAAT) expression and its relationship with demyelination, inflammation, gliosis, and neuronal and synaptic pathology. EAATs are essential in maintaining low extracellular glutamate concentrations and preventing excitotoxicity. Ten MS brains (3 relapsing-remitting MS cases and 7 secondary progressive MS cases) were evaluated by immunohistochemistry for myelin basic protein, CD68, HLA-DR, EAAT1, EAAT2, glial fibrillary acidic protein, phosphorylated c-Jun N-terminal kinase (pJNK), synaptophysin, and neurofilaments. Cortical lesions were frequently observed in MS brains in variable numbers and extensions. In cortical lesions, activated microglia infiltration correlated with focal loss of EAAT1, EAAT2, and synaptophysin immunostaining, and with neuronal immunostaining for pJNK, a protein involved in response to excitotoxic injury. No reduction of EAATs or synaptophysin immunostaining was observed in demyelinated cortex in the absence of activated microglia. Alterations of the mechanisms of glutamate reuptake are found in cortical MS lesions in the presence of activated microglia and are associated with signs of neuronal and synaptic damage suggestive of excitotoxicity. Excitotoxicity may be involved in the pathogenesis of demyelination and of neuronal and synaptic damage in MS cortex.

Expression of the neurogenic basic helix-loop-helix transcription factor NEUROG1 identifies a subgroup of medulloblastomas not expressing ATOH1.

To gain insight into the lineage of origin of medulloblastomas, the mRNA expression of NEUROG1, a gene encoding a proneural transcription factor transiently detected during nervous system development, was investigated in 27 human medulloblastomas characterized for mRNA expression of ATOH1, a marker of cerebellar granule precursors and corresponding medulloblastomas. Expression of Ngn1, the mouse homolog of NEUROG1, was also analyzed in the mouse cerebellar primordium. In addition, we studied mRNA expression of GLI1 as a marker of the SHH pathway activation, and nuclear beta-catenin staining, beta-catenin mutations, and mRNA expression of MYC as indicators of the WNT pathway status. In 15 cases, we also examined expression of OTX2, a transcription factor recently indicated as a positive marker of medulloblastomas originating from cerebellar granule precursors. The mRNA expression of NEUROG1 and Ngn1 was selectively found in medulloblastomas not expressing ATOH1 and in progenitors of the cerebellar ventricular zone, respectively. GLI1 transcript was expressed in medulloblastomas with ATOH1 transcript, whereas high levels of MYC transcript were unrelated to NEUROG1 or ATOH1 expression. No clear association between MYC overexpression and nuclear beta-catenin staining was found. Finally, OTX2 mRNA was expressed in all medulloblastomas with NEUROG1 transcript, but also in a subset of these malignancies with ATOH1 transcript. These observations may help to define the lineage of origin of medulloblastomas, and support a role for ATOH1 and NEUROG1 in the classification of these malignancies.