Biomedical subjects

Oded Abramsky

Publications and source records attributed to Oded Abramsky.

At least 19 recordsLinked to original sources

PubMed2006

Detection of circulating antibodies against tau protein in its unphosphorylated and in its neurofibrillary tangles-related phosphorylated state in Alzheimer's disease and healthy subjects.

While the presence of naturally occurring antibodies (Abs) against amyloid-beta in AD patients and healthy subjects have been repeatedly reported, no data on the presence of naturally occurring Abs against tau protein, in its unphosphorylated as well as its pathologically phosphorylated state, has been reported so far. We describe here the detection of circulating Abs against unphosphorylated and pathologically phosphorylated tau protein in sera of 17 aged subjects: nine Alzheimer's disease (AD) patients and eight healthy individuals. An ongoing autoimmune process may take place, as is suggested by the presence of both IgM class anti-tau Abs, as well as IgG. A preliminary evidence for higher anti-phosphorylated-tau Abs of IgM class in AD patients relative to controls is indicated, but demands further confirmation in a larger sample. Detection of naturally occurring anti-tau antibodies may point to the possibility that some autoimmune process may take place against the tau neuronal protein, including its pathologically phosphorylated state which compose the neurofibrillary tangles. Whether these Abs are neuroprotective or neurotoxic - is unknown, as it is with anti-amyloid-beta Abs.

Aged↗

PubMed2006

Novel approaches to treatment of autoimmune neuroinflammation and lessons for drug development.

Drug development, and especially that intended for central nervous system (CNS) disorders, still poses a challenge. We investigated both the use of bifunctional compounds designed for multiple targeting and enhanced CNS permeability, and of recombinant alpha-fetoprotein (AFP), a natural pregnancy-associated immunomodulating protein for the treatment of CNS inflammation. Bifunctional compounds showed a novel pharmacokinetic profile due to the conjugation, yet retained, and even improved pharmacodynamics. AFP was well tolerated and decreased various aspects of neuroinflammation, including disease severity, axonal loss and damage, T-cell reactivity, and antigen presentation. Our results show that both strategies may serve as future drug modalities.

Animals↗

PubMed2006

Occurrence of CNS demyelinating disease in patients with myasthenia gravis.

An increased incidence of multiple sclerosis (MS) has been reported in patients with myasthenia gravis (MG). We reviewed records of 214 patients with MG. CNS demyelinating disease (CNSDD) occurred in five patients (2.3%). CNSDD always occurred after the diagnosis of MG. Myelitis (including recurrent myelitis) was the most common CNS manifestation. All patients had antinuclear antibodies. CNSDD occurs more frequently in patients with MG and may be related to immune-modulating treatments including thymectomy.

Adolescent↗

PubMed2006

Transplanted neural precursor cells reduce brain inflammation to attenuate chronic experimental autoimmune encephalomyelitis.

Stem cell transplantation was introduced as a mean of cell replacement therapy, but the mechanism by which it confers clinical improvement in experimental models of neurological diseases is not clear. Here, we transplanted neural precursor cells (NPCs) into the ventricles of mice at day 6 after induction of chronic experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis (MS). Transplanted cells migrated into white matter tracts and attenuated the clinical course of disease. NPC transplantation down-regulated the inflammatory brain process at the acute phase of disease, as indicated by a reduction in the number of perivascular infiltrates and of brain CD3+ T cells, an increase in the number and proportion of regulatory T cells and a reduction in the expression of ICAM-1 and LFA-1 in the brain. Demyelination and acute axonal injury in this model are considered to result mainly from the acute inflammatory process and correlate well with the chronic neurological residua. In consequence to inhibition of brain inflammation, precursor cell transplantation attenuated the primary demyelinating process and reduced the acute axonal injury. As a result, the size of demyelinated areas and extent of chronic axonal pathology were reduced in the transplanted brains. We suggest that the beneficial effect of transplanted NPCs in chronic EAE is mediated, in part, by decreasing brain inflammation and reducing tissue injury.

Amyloid beta-Protein Precursor↗

PubMed2006

Amelioration of autoimmune neuroinflammation by recombinant human alpha-fetoprotein.

Alpha-fetoprotein (AFP) is a 65-kDa oncofetal glycoprotein found in fetal and maternal fluids during pregnancy. Clinical remissions during pregnancy have been observed in several autoimmune diseases, such as multiple sclerosis (MS), and have been attributed to the presence of pregnancy-associated natural immune-reactive substances, including AFP which can exert immunomodulatory effects on immune cells. In this study, we tested the effect of recombinant human AFP (rhAFP) isolated from transgenic goats, which contain the genomic DNA for hAFP, on experimental autoimmune encephalomyelitis (EAE), the animal model used for the study of MS. RhAFP treatment markedly improved the clinical manifestations of EAE, preventing central nervous system (CNS) inflammation and axonal degeneration. RhAFP exerted a broad immunomodulating activity, influencing the various populations of immune cells. T cells from treated mice had significantly reduced activity towards the encephalitogenic peptide of myelin oligodendrocyte glycoprotein (MOG), exhibiting less proliferation and reduced Th1 cytokine secretion. Moreover, AFP affected the humoral response, causing an inhibition in MOG-specific antibody production. The expression of CD11b, MHC class II and the chemokine receptor CCR5 was also down-regulated. This is the first study demonstrating reduced inflammation and axonal damage exerted by recombinant AFP. In light of our findings, rhAFP may serve as a potential candidate for treatment of MS and other autoimmune diseases.

Analysis of Variance↗

PubMed2006

Neuroprotection in multiple sclerosis.

In chronic inflammatory diseases like multiple sclerosis (MS), neuroprotection refers to strategies aimed at prevention of the irreversible damage of various neuronal and glial cell populations, and promoting regeneration. It is increasingly recognized that MS progression, in addition to demyelination, leads to substantial irreversible damage to, and loss of neurons, resulting in brain atrophy and cumulative disability. One of the most promising neuroprotective strategies involves the use of bone marrow derived stem cells. Both hematopoietic and non-hematopoietic (stromal) cells can, under certain circumstances, differentiate into cells of various neuronal and glial lineages. Neuronal stem cells have also been reported to suppress EAE by exerting direct in situ immunomodulating effects, in addition to their ability to provide a potential source for remyelination and neuroregeneration. Preliminary results from our laboratory indicate that intravenous or intracerebral/intraventricular injection of bone marrow derived stromal cells could differentiate in neuronal/glial cells and suppress the clinical signs of chronic EAE. Both bone marrow and neuronal stem cells may therefore have a therapeutic potential in MS. It seems that future treatment strategies for MS should combine immunomodulation with neuroprotective modalities to achieve maximal clinical benefit.

Humans↗

PubMed2006

Tauopathy-like abnormalities and neurologic deficits in mice immunized with neuronal tau protein.

BACKGROUND: A possible role of autoimmunity in Alzheimer disease pathogenesis has recently attracted increasing attention. Vaccination with amyloid-beta peptide was reported to cause marked reduction in amyloid deposition, but it also induced encephalitis. Not much is known regarding neurofibrillary tangle-related autoimmune effects. OBJECTIVE: To use the main component of tangles-microtubule-associated tau protein-to test the feasibility of active induction of a neuroautoimmune disorder in mice. DESIGN: Prospective, randomized controlled animal study. SETTING: University medical center research laboratory. Subjects Female C57BL/6 mice. INTERVENTIONS: Inoculation with recombinant human tau protein emulsified in complete Freund adjuvant and with pertussis toxin. MAIN OUTCOME MEASURES: Clinical, immunologic, pathologic, and behavioral evaluations were performed. RESULTS: Vaccination with tau protein induced histopathologic features of Alzheimer disease and tauopathies, indicated by the presence of neurofibrillary tangle-like structures, axonal damage, and gliosis. Also, mononuclear infiltrates without demyelination in the central nervous system, accompanied by neurologic deficits (such as a limp tail and limb paralysis), were observed. Anti-tau antibodies were detected in the serum of tau-immunized mice. CONCLUSIONS: These results provide a link between tau autoimmunity and tauopathy-like abnormalities and indicate potential dangers of using tau for immunotherapy. This experimental autoimmune tauopathy-like model is due to a pathogenic immune response against an intraneuronal antigen and is not related to myelin antigens.

Alzheimer Disease↗

PubMed2006

Phenotypic variability among adult siblings with Sjögren-Larsson syndrome.

BACKGROUND: Sjögren-Larsson syndrome (SLS) is an early childhood-onset disorder with ichthyosis, mental retardation, spastic paraparesis, macular dystrophy, and leukoencephalopathy caused by the deficiency of fatty aldehyde dehydrogenase due to mutations in the ALDH3A2 gene (the gene that encodes microsomal fatty aldehyde dehydrogenase). Cerebral proton magnetic resonance spectroscopy in those with SLS demonstrates an abnormal white matter peak at 1.3 ppm, consistent with long-chain fatty alcohol accumulation. OBJECTIVE: To define the clinical course and proton magnetic resonance spectroscopic findings of SLS in adults. DESIGN AND SETTING: Case series in a tertiary care center. PATIENTS: Six siblings of a consanguineous Arab family with early childhood-onset SLS who carry the 682C-->T mutation in the ALDH3A2 gene were reinvestigated in adulthood. RESULTS: The 6 affected siblings ranged in age from 16 to 36 years. All exhibited the typical clinical and imaging manifestations of SLS, but their severity markedly varied. Neurological involvement was apparently nonprogressive, and its severity showed no correlation with age. Cerebral proton magnetic resonance spectroscopy showed a lipid peak at 1.3 ppm, with decreasing intensity in the older siblings. CONCLUSION: These observations document significant clinical variability and the nonprogressive neurological course of SLS in adult siblings with the same ALDH3A2 genotype, and demonstrate possible correlation of proton magnetic resonance spectroscopic changes with age, suggesting unknown pathogenic mechanisms to compensate for the responsible biochemical defect in this disease.

Adolescent↗

PubMed2006

Hereditary spastic paraplegia with thin corpus callosum: reduction of the SPG11 interval and evidence for further genetic heterogeneity.

BACKGROUND: Hereditary spastic paraplegia (HSP) with thin corpus callosum (TCC) is an autosomal recessive form of complicated HSP mainly characterized by slowly progressive spastic paraparesis and mental deterioration beginning in the second decade of life. The locus for HSP-TCC, designated SPG11, was mapped to chromosome 15q13-15 in some of the affected families from Japan, Europe, and North America, spanning an interval of 17.5 megabases (Mb). OBJECTIVE: To perform a clinical and genetic study of HSP-TCC. DESIGN AND SETTING: Case series; multi-institutional study. PATIENTS: Seven patients with HSP-TCC who belong to 3 consanguineous families of Arab origin residing in Israel. RESULTS: The 7 patients manifested a relatively similar combination of adolescence-onset cognitive decline and spastic paraparesis with TCC on brain magnetic resonance imaging. After excluding the SPG7 locus, we tested the 3 families for linkage to the SPG11, SPG21/MAST, and ACCPN loci associated with autosomal recessive disorders with TCC. Two families showed evidence for linkage to SPG11 (Z(max) = 5.55) and reduced the candidate region to 13 Mb. CONCLUSIONS: Our findings in HSP-TCC further confirm its worldwide distribution and genetic heterogeneity, and they significantly reduce the candidate SPG11 interval.

Adult↗

PubMed2006

[Autoimmune mechanisms in paraneoplastic neurological diseases: the paradigm of opsoclonus myoclonus ataxia syndrome].

Paraneoplastic Neurologic Diseases (PND) are remote complications of certain neoplastic diseases characterized by distinct neurological deficits in the central as well as the peripheral nervous system. The neurological disorders are usually clinically evident before the cancer is identified. PND are rare syndromes believed to have an immunological link where antibodies or activated T cells are acting against self antigens shared by the tumor cells and neurons. Most of these onconeural antigens are located in the cytoplasm-nuclear compartment of the cell, whereas others are located at the membrane and act as receptors or ion channels. This short review discusses the autoimmune mechanisms involved in PND in general and in opsoclonus-myoclonus-ataxia in particular. The article attempts to clarify why in most PND the immune effector mechanisms against onconeural antigens detected in sera of patients may not be the direct cause of the neurological deficit. We elaborate on the difference between the immune response against cytoplasmic-nuclear antigens as opposed to membranal antigens with regard to the fact that: a) the nervous system is considered immune privileged; b) neither the tumors nor the neurons have an optimal expression of MHC class I antigens and onconeural epitopes on the membrane. The availability of onconeural antigens to the immune effectors mechanisms is probably the main reason why there are few animal models for PND.

Autoimmune Diseases↗

PubMed2005

Extrathymic malignancies in patients with myasthenia gravis.

INTRODUCTION: Myasthenia gravis (MG) is considered a paraneoplastic phenomenon of thymomas in 15% of patients. Co-existence of MG with extrathymic malignancies, and an increased risk of second malignancy in patients with thymoma have been reported. Data on clinical characteristics of MG patients with extrathymic malignancies and the role of concomitant diseases and their treatment are lacking. METHODS: The clinical records of 188 consecutive MG patients were studied retrospectively. We examined whether gender, age, generalized disease, seropositivity for acetyl-choline receptor antibodies, occurrence of thymoma, immunosuppressive therapy and occurrence of other autoimmune diseases determined an increased risk for development of extrathymic malignancy. RESULTS: This group followed the typical epidemiological characteristics of MG. Thirty-three patients (17.6%) had a thymoma. Twenty-nine patients (15.4%) had 30 extrathymic malignant tumors of various origins. Only four patients with extrathymic tumors had an associated thymoma. Tumors were diagnosed between 20 years prior to and 35 years after the appearance of MG. Older age of MG onset was the only risk factor identified for development of malignancy in MG. DISCUSSION: Extrathymic malignancies are common in MG patients, especially in the older age group. There are no specific clinical features of the subgroup of MG patients with cancer. Although MG is not a paraneoplastic phenomenon of extrathymic malignancy, the association between MG and malignancy may be due to a common background of immune dysregulation.

Adult↗

PubMed2005

Polyneuropathy associated with interferon beta treatment in patients with multiple sclerosis.

Peripheral neuropathy has been reported as a side effect of interferon alpha, but not with interferon beta (IFNbeta) treatment. The authors assessed six patients with multiple sclerosis who developed polyneuropathy, or had exacerbation of previously subclinical neuropathy, during treatment with IFNbeta. In five patients the neuropathy improved after discontinuation of treatment and in two patients it relapsed upon rechallenge.

Adult↗

PubMed2005

Extended phenotype in the transthyretin Tyr77 familial amyloid polyneuropathy.

The transthyretin Tyr77 variant of familial amyloid polyneuropathy (FAP) has been identified in a few North American and European patients, but the full spectrum of its clinical manifestations is still not known. We report a 3-generation family of Jewish-Yemenite origin with Tyr77 FAP presenting with atypical features. The affected individuals had sensorimotor and autonomic neuropathy and cardiomyopathy accompanied by prominent dysphagia, hearing loss and asymptomatic carpal tunnel syndrome. Brain MRI in the proband showed multifocal white matter lesions. These features extend the reported Tyr77 phenotype and support the modifying effect of additional factors on the disease expression.

Amyloid Neuropathies, Familial↗

PubMed2005

Early clinical heterogeneity in choreoacanthocytosis.

BACKGROUND: Choreoacanthocytosis (CHAC) is a slowly progressive multisystem disorder with involuntary movements, cognitive decline, behavioral changes, seizures, and polyneuropathy caused by mutations in the VPS13A gene. OBJECTIVE: To describe the early clinical features and possible genotype-phenotype correlation in CHAC. DESIGN AND SETTING: Case series in a tertiary care center. PATIENTS AND MAIN OUTCOME METHODS: Choreoacanthocytosis was diagnosed in 3 patients of Jewish origin from 3 unrelated families. We reviewed their medical histories and performed molecular analysis by screening all 73 exons of VPS13A. RESULTS: Trichotillomania, hypertrophic cardiomyopathy, and idiopathic hyperCKemia, in 1 patient each, preceded the development of the full clinical spectrum of CHAC by 2 to 20 years. At diagnosis, 2 patients manifested signs of overt neuromuscular involvement and were homozygous for the 6059delC mutation, whereas 1 patient had only hyporeflexia and was homozygous for the EX23del mutation. Because only 1 of the 2 patients with 6059delC had cardiomyopathy, its relevance to CHAC is unclear. CONCLUSIONS: These findings extend the knowledge of significant early clinical heterogeneity in CHAC and suggest a possible genotype-phenotype correlation. Awareness of the early manifestations may prevent misdiagnosis and enable appropriate genetic counseling.

Adult↗

PubMed2004

A novel autosomal recessive myopathy with external ophthalmoplegia linked to chromosome 17p13.1-p12.

We describe a new autosomal recessive myopathy of early onset and very slow progression distinguished by the prominent external ophthalmoplegia in 16 subjects of eight families from a large and highly inbred Arab community. Characteristic clinical features include mild facial and skeletal muscle weakness and atrophy more pronounced proximally in the upper limbs, facial dysmorphism and scoliosis associated with conjugate, non-restrictive ocular motility impairment greatest in the upgaze and without ptosis or aberrant eye movements. Orbital MRI in the patients demonstrated atrophy with fatty replacement of the oculorotatory muscles. The major pathological alteration on skeletal muscle biopsy was a marked type 1 fibre predominance with core-like formations. A genome wide search for regions of homozygosity in the affected members from two informative families identified linkage with chromosome 17p13.1-p12 markers. Maximum two-point logarithm of odds scores were obtained at loci D17S1803 and AFMA070WD1 (Zmax = 3.74 at = 0). Two independent recombination events at D17S1812 and D17S947 further defined a critical region of 12 cM. Several genes map to this interval, including a cluster of sarcomeric myosin heavy chain genes. One of these genes, MYH2, is involved in inclusion body myopathy 3, but no exonic mutations were found by direct sequencing. The molecular basis for this new myopathy remains to be identified.

Adolescent↗

PubMed2004

An association study of a polymorphism in the heparan sulfate proteoglycan gene (perlecan, HSPG2) and Alzheimer's disease.

Accumulating evidence indicates that the heparan-sulfate-proteoglycan (perlecan, HSPG2), as well as other specific proteoglycans, are involved in amyloidogenesis and tau aggregation in Alzheimer's disease (AD). Moreover, the HSPG2 is located on chromosome 1p36, a region of linkage to late-onset AD (LOAD). These two criteria, pathological and positional, make the HSPG2 an interesting candidate for an association with AD. We performed a case-control association study between the common intron 6 BamHI polymorphism at a region of putative heparan-sulfate (HS) attachment sites in the HSPG2 gene and sporadic AD in Jews. No association was detected with AD, neither as a risk factor nor as a modifier gene affecting the age at disease onset and disease progression. In addition, no interactive effect was found with the known risk factor for AD, the apolipoprotein E (APOE) epsilon4. These findings show no evidence for association between HSPG2 intron 6 BamHI polymorphism and AD in our population.

Age of Onset↗

PubMed2004

Lack of association of interleukin-1beta polymorphism with Alzheimer's disease in the Jewish population.

A growing body of evidence suggests that Alzheimer's disease (AD) is associated with local inflammation processes, including the activation of inflammatory cytokines. We performed a case-control association study between sporadic AD patients and the exon 5 position +3953 polymorphism in the potent pro-inflammatory cytokine, interleukin-1beta (IL-1B). Recent association studies of this locus with AD revealed conflicting results, suggesting that the association - if it exists - is not universal but rather population specific. In our study no association was detected with AD: neither as a risk factor nor as a modifier gene affecting the age at onset and disease progression. These findings show no evidence for an association between the IL-1B +3953 polymorphism and AD in the Jewish population.

Age of Onset↗

PubMed2004

The Fas promoter polymorphism at position -670 is not associated with late-onset sporadic Alzheimer's disease.

The Fas antigen is a cell surface receptor-mediating cell apoptosis. Recent studies have demonstrated that Fas-associated apoptosis is involved in the pathogenesis of Alzheimer's disease (AD). Moreover, the Fas gene is located on chromosome 10q24.1, a region of linkage to late-onset AD (LOAD). These two criteria, pathobiological and positional, make the Fas antigen an interesting candidate for an association with AD. We performed a case-control association study between the common A/G polymorphism at position -670 in the Fas gene (TNFSRF6) promoter and sporadic AD in Jews, investigating whether this locus acts as a risk factor or whether it has a modifying effect. An association has recently been detected by Feuk et al. in the Scottish population between this locus and the risk of early-onset AD (EOAD), but not of LOAD. In agreement with Feuk et al., we found no association between this locus and the risk of LOAD (n = 86). However, in our small sample of patients with EOAD (n = 19), no association was found either. No interactive effect was found between the Fas promoter polymorphism at position -670 and the known risk factor of LOAD, apolipoprotein E epsilon4, and no association was detected with disease progression. These findings show no evidence for an association between the Fas promoter polymorphism at position -670 and AD in our population.

Aged↗