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Raphael Schiffmann

Publications and source records attributed to Raphael Schiffmann.

At least 19 recordsLinked to original sources
PubMed2006

Cellular and tissue distribution of intravenously administered agalsidase alfa.

alpha-Galactosidase A is the lysosomal hydrolase that is deficient in patients with Fabry disease. Intravenous infusion of agalsidase alfa, a preparation of alpha-Galactosidase A, is used for enzyme replacement therapy (ERT) in patients with Fabry disease. Although ERT appears to show some beneficial effects, most patients show only a modest response. We investigated using immunohistochemistry the relative tissue and cellular distribution of agalsidase alfa after a single intravenous injection in a mouse knockout model of Fabry disease. Specific immunostaining for agalsidase alfa was found only in liver, kidney, heart, testes, adrenal gland, spleen and bone marrow. There was no difference in distribution of the infused enzyme distribution among tissues sampled 4, 24, and 48h post-injection. The intracellular localization of immunopositivity varied considerably between organs with vascular endothelium being the most commonly positive site. alpha-Galactosidase A specific activity in tissue homogenates matched the relative extent of agalsidase alfa immunostaining distribution in the same organs. We conclude that intravenously injected agalsidase alfa has a very heterogeneous systemic distribution using an immunostaining technique.

Animals↗
PubMed2006

Lamin B1 duplications cause autosomal dominant leukodystrophy.

Adult-onset autosomal dominant leukodystrophy (ADLD) is a slowly progressive neurological disorder characterized by symmetrical widespread myelin loss in the central nervous system, with a phenotype similar to chronic progressive multiple sclerosis. In this study, we identify a genomic duplication that causes ADLD. Affected individuals carry an extra copy of the gene for the nuclear laminar protein lamin B1, resulting in increased gene dosage in brain tissue from individuals with ADLD. Increased expression of lamin B1 in Drosophila melanogaster resulted in a degenerative phenotype. In addition, an abnormal nuclear morphology was apparent when cultured cells overexpressed this protein. This is the first human disease attributable to mutations in the gene encoding lamin B1. Antibodies to lamin B are found in individuals with autoimmune diseases, and it is also an antigen recognized by a monoclonal antibody raised against plaques from brains of individuals with multiple sclerosis. This raises the possibility that lamin B may be a link to the autoimmune attack that occurs in multiple sclerosis.

Animals↗
PubMed2006

Childhood ataxia with CNS hypomyelination/vanishing white matter disease--a common leukodystrophy caused by abnormal control of protein synthesis.

Mutations in eukaryotic initiation factor 2B (eIF2B) cause one of the most common leukodystrophies, childhood ataxia with CNS hypomyelination/vanishing white matter disease or CACH/VWM. Patients may develop a wide spectrum of neurological abnormalities from prenatal-onset white matter disease to juvenile or adult-onset ataxia and dementia, sometimes with ovarian insufficiency. The pattern of diffuse white matter abnormalities on MRI of the head is often diagnostic. Neuropathological abnormalities indicate a unique and selective disruption of oligodendrocytes and astrocytes with sparing of neurons. Marked decrease of asialo-transferrin in cerebrospinal fluid is the only biochemical abnormality identified thus far. Eukaryotic translation initiation factor 2B (eIF2B) mutations cause a decrease in guanine nucleotide exchange activity on eIF2-GDP, resulting in increased susceptibility to stress and enhanced ATF4 expression during endoplasmic reticulum stress. eIF2B mutations are speculated to lead to increased susceptibility to various physiological stress conditions. Future research will be directed towards understanding why abnormal control of protein translation predominantly affects brain glial cells.

Brain↗
PubMed2006

PLP1 and GPM6B intragenic copy number analysis by MAPH in 262 patients with hypomyelinating leukodystrophies: Identification of one partial triplication and two partial deletions of PLP1.

The proteolipid protein 1 (PLP1) gene is known to be mutated in the X-linked disorders of myelin formation Pelizaeus-Merzbacher disease (PMD) and spastic paraplegia type 2. The most commonly found PLP1 mutations are gene duplications (60-70%) and point mutations (20%). About 20% of patients with a PMD phenotype do not present identified PLP1 mutation, thus suggesting genetic heterogeneity and/or undetected PLP1 abnormalities. Except the recently described MLPA screening the seven exonic regions, the currently used techniques to quantify PLP1 gene copy number do not investigate small intragenic PLP1 rearrangements. Using the multiplex amplifiable probe hybridization (MAPH) technique, we looked simultaneously for intragenic rearrangements along the PLP1 gene (exonic and regulatory regions) and for rearrangements in the GPM6B candidate gene (a member of the proteolipid protein family). We tested 262 hypomyelinating patients: 56 PLP1 duplicated patients, 1 PLP1 triplicated patient, and 205 patients presenting a leukodystrophy of undetermined origin with brain MRI suggesting a defect in myelin formation. Our results show that MAPH is an alternative reliable technique for diagnosis of PLP1 gene copy number. It allows us (1) to demonstrate that all PLP1 duplications previously found encompass the whole gene, (2) to establish that copy number changes in GPM6B and intragenic duplications of PLP1 are very unlikely to be involved in the etiology of UHL, and (3) to identify one partial triplication and two partial deletions of PLP1 in patients presenting with a PMD phenotype.

Female↗
PubMed2006

Enzyme replacement therapy and intraepidermal innervation density in Fabry disease.

We prospectively evaluated the effect of enzyme replacement therapy (ERT) on the intraepidermal nerve fiber density (IENFD) and thermal threshold in patients with Fabry disease, an X-linked disorder associated with a painful small-fiber neuropathy and decreased linear IENFD in a length-dependent pattern. Twenty-five hemizygous male patients with Fabry disease were enrolled in a 6-month, randomized, placebo-controlled ERT trial of 0.2 mg/kg of alpha-galactosidase A (agalsidase-alfa) every 2 weeks followed by an additional 12 months of open-label ERT for both populations. IENFD and thermal threshold were measured in the distal thigh at baseline, 6 months, and 18 months from initiation of the trial. We found no significant difference in IENFD between the treatment groups at 6 months. After an additional year of ERT, there was a significant reduction in IENFD in the patient group as a whole, attributable to the declining glomerular filtration rate. Thermal thresholds remained unchanged. We conclude that epidermal nerve fiber regeneration, as measured in the distal thigh, does not occur in this patient population after 12-18 months of ERT.

Adult↗
PubMed2006

Quantitative dysmorphology assessment in Fabry disease.

PURPOSE: 1) To identify morphometric characteristics in hemizygous patients with Fabry disease a treatable lysosomal storage disorder caused by the deficiency of alpha-galactosidase A where morphological abnormalities have occasionally been mentioned, but have never been investigated systematically. 2) To devise a quantitative method to evaluate dysmorphic abnormalities in Fabry disease. METHOD: Cross-sectional, single center, independent dysmorphology assessment by a panel of three clinical geneticists, based on standardized medical photography. POPULATION: consecutive hemizygous patients with Fabry disease (N = 38) unselected for the features assessed, mean age 38 +/- 10.8 years (range: 10-60), recruited for neuropathic pain into enzyme replacement therapy trials. RESULTS: The following dysmorphic features were identified (in order of descending frequency): periorbital fullness, prominent lobules of the ears, bushy eyebrows, recessed forehead, pronounced nasal angle, generous nose/bulbous nasal tip, prominent supraorbital ridges, shallow midface, full lips, prominent nasal bridge, broad alar base, coarse features, posteriorly rotated ears, and prognathism. Extremity features included broad fingertips, short fingers, prominent superficial vessels of hands, 5 digit brachydactyly, and 5 digit clinodactyly. Narrow anterior-posterior chest diameter was noted. Ten core features were statistically defined. Cronbach's alpha measuring internal consistency was 0.62. Light's kappa for global inter-rater variability was 0.26 while Cohen's kappa allowing pair-wise rater comparison varied between 0.08-0.48. CONCLUSIONS: Patients with Fabry disease share common morphological characteristics of the face, trunk, and extremities. Some of these features are subtle as documented by the inter-rater variability. Awareness of these features may facilitate the diagnosis of patients with Fabry disease, and identification of affected family members.

Adolescent↗
PubMed2006

Fabry disease and vascular risk factors: future strategies for patient-based studies and the knockout murine model.

UNLABELLED: Fabry disease is secondary to deficiency of the lysosomal enzyme alpha-galactosidase A, leading to altered glycosphingolipid metabolism and accumulation that is often associated with endothelial dysfunction. Current evidence suggests that there is impairment of the vascular nitric oxide pathway, with abnormalities evident in the cerebral circulation and in the dermal vasculature of patients with Fabry disease. Some of these findings have been confirmed in a mouse model of Fabry disease. The murine model, however, allows investigation of Fabry disease at a non-clinical level and a near complete investigation of biological processes within an affected tissue. This is of particular utility in allowing gene expression analysis of clinically inaccessible tissues such as the aorta. CONCLUSION: Future developments in array technology for proteins and DNA single nucleotide polymorphism analysis, together with gene expression microarray analysis, may open a new chapter in our understanding of the biology of lysosomal storage disorders.

Animals↗
PubMed2006

Enzyme-replacement therapy with agalsidase alfa in children with Fabry disease.

CONTEXT: Fabry disease is an X-linked multisystem disorder. Enzyme-replacement therapy in adults has limited efficacy in treating major sequelae of advanced Fabry disease, such as kidney failure or stroke. This prompted a study of the safety and efficacy of enzyme replacement at an earlier stage of Fabry disease. OBJECTIVES: Our purpose with this work was to evaluate safety and to explore efficacy of enzyme treatment with agalsidase alfa in pediatric patients with Fabry disease. METHODS: We conducted a 6-month open-label study at 3 tertiary care centers with 24 children (19 boys and 5 girls) with a mean age of 11.8 (range: 6.5-18) years, to examine safety parameters, including infusion reactions and antiagalsidase alfa antibodies. RESULTS: Agalsidase alfa was well tolerated, and all of the patients completed the study. Six boys and 1 girl had mild-to-moderate infusion reactions. One boy developed transient immunoglobulin G antibodies against agalsidase alfa. The boys showed a significant reduction in plasma globotriaosylceramide on treatment. Mean estimated glomerular filtration rate, cardiac structure, and function were normal and did not change over 26 weeks. Heart rate variability, as determined by 2-hour ambulatory monitoring, was decreased in the boys compared with the girls at baseline. All indices of heart rate variability improved significantly in the boys. Three patients with anhidrosis, as determined by quantitative sudomotor axon reflex testing, developed sweating. Six of 11 patients could reduce or cease their use of antineuropathic analgesics. CONCLUSIONS: Enzyme replacement with agalsidase alfa was safe in this study. The exploratory efficacy analysis documented increased clearance of globotriaosylceramide and improvement of autonomic function. Prospective long-term studies are needed to assess whether enzyme replacement initiated early in patients with Fabry disease is able to prevent major organ failure in adulthood.

Adolescent↗
PubMed2006

Neuropathy and Fabry disease: pathogenesis and enzyme replacement therapy.

The neurological manifestations of Fabry disease include both peripheral and central nervous system involvement caused by a deficiency of alpha-galactosidase A and accumulation of alpha-D-galactosyl moieties, particularly globotriosylceramide accumulation (Gb3). These are found in Schwann cells and dorsal root ganglia together with deposits in central nervous system neurons. Involvement of the peripheral nervous system affect mainly small Adelta and C fibers and are likely causally related to the altered autonomic function and neuropathic pain found in this disorder. Other related abnormalities to be discussed are hypohidrosis and other abnormalities attributed to autonomic nervous system dysfunction. The function of the peripheral nervous system is somewhat improved by ERT with reduction in neuropathic pain and an improvement of the detection threshold for cold and warm sensation in the hand and foot. Improvement in sweating and heat tolerance is also noted following ERT. Despite those positive results, ERT does not normalize the function of the peripheral nervous system.

Fabry Disease↗
PubMed2005

Pathological findings in a patient with Fabry disease who died after 2.5 years of enzyme replacement.

We describe the postmortem findings of a 47-year-old man with Fabry disease, an X-linked glycolipid storage disorder, who was on enzyme replacement therapy with recombinant alpha-galactosidase A for more than 2 years. The patient had widespread atherosclerotic coronary artery disease that culminated in a massive acute myocardial infarction. Atherosclerotic lesions were seen in the right and left coronary systems, aorta, and the basilar artery. Typical Fabry cardiomyopathy and glomerular nephropathy were found. With the exception of vascular endothelial cells, extensive glycolipid storage deposits were seen in all vascular and nonvascular cells and organ systems. We conclude that, at least in this patient, repeated infusions with alpha-galactosidase A over a prolonged period did not appreciably clear storage material in cells other than vascular endothelial cells. These findings also illustrate accelerated atherosclerosis in susceptible patients with Fabry disease.

Coronary Artery Disease↗
PubMed2005

Heightened stress response in primary fibroblasts expressing mutant eIF2B genes from CACH/VWM leukodystrophy patients.

Childhood ataxia with central nervous system hypomyelination (CACH), also called vanishing white matter (VWM) leukoencephalopathy, is a fatal genetic disease caused by mutations in eukaryotic initiation factor 2B (eIF2B) genes. The five subunits eIF2B factor is critical for translation initiation under normal conditions and regulates protein synthesis in response to cellular stresses. Primary fibroblasts from CACH/VWM patients and normal individuals were used to measure basal eIF2B activity as well as global protein synthesis and ATF4 induction in response to stress in the endoplasmic reticulum. We show that although the cells expressing mutant eIF2B genes respond normally to stress conditions by reduced global translation rates, they exhibit significantly greater increase in ATF4 induction compared to normal controls despite equal levels of stress and activity of the upstream eIF2alpha kinase. This heightened stress response observed in primary fibroblasts that suffer from minor loss of basal eIF2B activity may be employed as an initial screening tool for CACH/VWM leukodystrophy.

Activating Transcription Factor 4↗
PubMed2005

Long-term therapy with agalsidase alfa for Fabry disease: safety and effects on renal function in a home infusion setting.

BACKGROUND: Fabry disease is an X-linked disorder of glycosphingolipid catabolism that is the result of an intracellular deficiency in the lysosomal enzyme alpha-galactosidase A (alpha-Gal A). This enzymatic defect results in the accumulation of globotriaosylceramide (Gb(3)) within cells and causes progressive neurological, cardiovascular and renal dysfunction. Our objective is to describe the safety and renal effects of long-term enzyme replacement therapy. METHODS: This was a single centre, prospective open-label treatment trial in 25 adult male Fabry patients who had completed a 6-month randomized placebo-controlled study and subsequently enrolled in an open-label extension study. Patients were treated every other week with agalsidase alfa (0.2 mg/kg) infused intravenously over 40 min. The main outcome measures were safety, antibody response and renal glomerular filtration rate (GFR). RESULTS: During the 4-4.5 years of enzyme replacement therapy, all eligible subjects were able to transition to home therapy. Eight patients developed persistent IgG antibodies to agalsidase alfa, but IgE antibodies were not detected in any patient. The development of IgG antibodies appeared not to affect any clinical end points. Estimated GFR remained stable in subgroups of patients with Stage I (GFR >90 ml/min) or Stage II (GFR 60-89 ml/min) chronic kidney disease at baseline. In contrast, in the subgroup of patients with Stage III chronic kidney disease (GFR 30-59 ml/min), the slope of the decline in GFR was reduced compared with comparable historical controls, suggesting that enzyme replacement therapy was slowing the decline of renal function in this susceptible population. CONCLUSIONS: Long-term enzyme replacement therapy with agalsidase alfa is safe and may slow the progressive decline in renal function that was commonly observed in adult males with Fabry disease.

Adult↗
PubMed2005

Improved intracellular delivery of glucocerebrosidase mediated by the HIV-1 TAT protein transduction domain.

Enzyme replacement therapy (ERT) for Gaucher disease designed to target glucocerebrosidase (GC) to macrophages via mannose-specific endocytosis is very effective in reversing hepatosplenomegaly, and normalizing hematologic parameters but is less effective in improving bone and lung involvement and ineffective in brain. Recombinant GCs containing an in-frame fusion to the HIV-1 trans-activator protein transduction domain (TAT) were expressed in eukaryotic cells in order to obtain active, normally glycosylated GC fusion proteins for enzyme uptake studies. Despite the absence of mannose-specific endocytic receptors on the plasma membranes of various fibroblasts, the recombinant GCs with C-terminal TAT fusions were readily internalized by these cells. Immunofluorescent confocal microscopy demonstrated the recombinant TAT-fusion proteins with a mixed endosomal and lysosomal localization. Thus, TAT-modified GCs represent a novel strategy for a new generation of therapeutic enzymes for ERT for Gaucher disease.

Base Sequence↗
PubMed2005

Decreased asialotransferrin in cerebrospinal fluid of patients with childhood-onset ataxia and central nervous system hypomyelination/vanishing white matter disease.

BACKGROUND: A biomarker for the diagnosis of childhood-onset ataxia and central nervous system hypomyelination (CACH)/vanishing white matter disease (VWM) would have clinical utility and pathophysiologic significance. METHODS: We used 2-dimensional gel electrophoresis/mass spectrometry to compare the cerebrospinal fluid proteome of patients with mutation-confirmed CACH/VWM with that of unaffected controls. We characterized selected spots by in-gel digestion, matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry, and nanospray Fourier transform mass spectrometry. RESULTS: A specific transferrin spot pattern was detected in the CSF samples of the CACH/VWM group (n = 7), distinguishing them from the control group (n = 23) and revealing that patients with CACH/VWM have a deficiency of the asialo form of transferrin usually present in healthy cerebrospinal fluid. The glycopeptide structure, determined from isolated transferrin spots by use of in-gel digestion and extraction, was found to be consistent with earlier reports. CONCLUSIONS: The transferrin isoform abnormality in the cerebrospinal fluid of patients with CACH/VWM appears unique and is a potential clinical diagnostic biomarker. The rapid, efficient diagnosis of this disorder would have a significant impact on clinical studies exploring new strategies for the management and treatment of this disease.

Asialoglycoproteins↗
PubMed2005

Effect of genetic modifiers on cerebral lesions in Fabry disease.

Fabry disease is associated with increased risk of premature stroke and presumptive ischemic cerebral lesions. In 57 consecutive patients, 35% of whom had lesions on brain MRI, the authors found that genotypes of polymorphisms G-174C of interleukin-6, G894T of endothelial nitric oxide synthase, factor V G1691A mutation, and the A-13G and G79A of protein Z were all significantly associated with cerebral lesions. These findings suggest that these proteins modulate Fabry cerebral vasculopathy.

Adolescent↗