Aging accentuates and bone marrow transplantation ameliorates metabolic defects in Fabry disease mice.
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Fabry disease is an X-linked metabolic disorder caused by a deficiency of alpha-galactosidase A (alpha-Gal A). The enzyme defect leads to the systemic accumulation of glycosphingolipids with alpha-galactosyl moieties consisting predominantly of globotriaosylceramide (Gb3). In patients with this disorder, glycolipid deposition in endothelial cells leads to renal failure and cardiac and cerebrovascular disease. Recently, we generated alpha-Gal A gene knockout mouse lines and described the phenotype of 10-week-old mice. In the present study, we characterize the progression of the disease with aging and explore the effects of bone marrow transplantation (BMT) on the phenotype. Histopathological analysis of alpha-Gal A -/0 mice revealed subclinical lesions in the Kupffer cells in the liver and macrophages in the skin with no gross lesions in the endothelial cells. Gb3 accumulation and pathological lesions in the affected organs increased with age. Treatment with BMT from the wild-type mice resulted in the clearance of accumulated Gb3 in the liver, spleen, and heart with concomitant elevation of alpha-Gal A activity. These findings suggest that BMT may have a potential role in the management of patients with Fabry disease. (+info)
Fifteen-year follow-up of a heterozygous Fabry's disease patient associated with pre-excitation syndrome.
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A 47-year-old woman with heterozygous Fabry's disease with pre-excitation syndrome has been followed up for 15 years. Diagnosis was confirmed by the typical electron microscopic feature of the endomyocardial specimen and a decreased plasma alpha-galactosidase activity. As the disease progressed, the interventricular septum thickened from 11 to 17 mm as measured by echocardiography, while the AH interval was prolonged from 80 to 140 msec. In Fabry's disease, the PR interval has been reported to be variable from short PR to AV block. Therefore, this case may be helpful to understand the time course in the AV conduction abnormalities with the progression of Fabry's disease. (+info)
Biopsy-proven cardiomyopathy in heterozygous Fabry's disease.
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A 23-year-old woman with heterozygous Fabry's disease who had acroparesthesia was admitted to hospital for precise examination of the disease before childbearing. She had no cardiac-related symptoms and no abnormality on physical examination. The alpha-galactosidase A activity in her leukocytes was present, but lower than normal. However, the endomyocardial biopsy showed specific changes for Fabry's disease. As Fabry's disease is a rare X-linked recessive inborn error of glycosphingolipid metabolism, heterozygous females are usually asymptomatic, but rarely can be affected as severely as hemizygous males. This is an isolated case of heterozygous Fabry's disease in a female in whom cardiac involvement was detected by endomyocardial biopsy, although she had no cardiac abnormality on physiological examinations. In conclusion, endomyocardial biopsy is useful for evaluation of the cardiac involvement of Fabry's disease even in an asymptomatic case. (+info)
Infusion of alpha-galactosidase A reduces tissue globotriaosylceramide storage in patients with Fabry disease.
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Fabry disease is a lysosomal storage disorder caused by a deficiency of the lysosomal enzyme alpha-galactosidase A (alpha-gal A). This enzymatic defect results in the accumulation of the glycosphingolipid globotriaosylceramide (Gb(3); also referred to as ceramidetrihexoside) throughout the body. To investigate the effects of purified alpha-gal A, 10 patients with Fabry disease received a single i.v. infusion of one of five escalating dose levels of the enzyme. The objectives of this study were: (i) to evaluate the safety of administered alpha-gal A, (ii) to assess the pharmacokinetics of i.v.-administered alpha-gal A in plasma and liver, and (iii) to determine the effect of this replacement enzyme on hepatic, urine sediment and plasma concentrations of Gb(3). alpha-Gal A infusions were well tolerated in all patients. Immunohistochemical staining of liver tissue approximately 2 days after enzyme infusion identified alpha-gal A in several cell types, including sinusoidal endothelial cells, Kupffer cells, and hepatocytes, suggesting diffuse uptake via the mannose 6-phosphate receptor. The tissue half-life in the liver was greater than 24 hr. After the single dose of alpha-gal A, nine of the 10 patients had significantly reduced Gb(3) levels both in the liver and shed renal tubular epithelial cells in the urine sediment. These data demonstrate that single infusions of alpha-gal A prepared from transfected human fibroblasts are both safe and biochemically active in patients with Fabry disease. The degree of substrate reduction seen in the study is potentially clinically significant in view of the fact that Gb(3) burden in Fabry patients increases gradually over decades. Taken together, these results suggest that enzyme replacement is likely to be an effective therapy for patients with this metabolic disorder. (+info)
Glycosphingolipid depletion in fabry disease lymphoblasts with potent inhibitors of glucosylceramide synthase.
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BACKGROUND: Fabry disease is an inherited X-linked disorder resulting in the loss of activity of the lysosomal hydrolase alpha-galactosidase A and causing the clinical manifestations of renal failure, cerebral vascular disease, and myocardial infarction. The phenotypic expression of this disorder is manifest by the accumulation of glycosphingolipids containing alpha-galactosyl linkages, most prominently globotriaosylceramide. METHODS: Based on quantitative structure activity studies, we recently reported two newly designed glucosylceramide synthase inhibitors based on 1-phenyl-2-palmitoylamino-3-pyrrolidino-1-propanol (P4). These inhibitors, 4'-hydroxy-P4 and ethylenedioxy-P4, were evaluated for their ability to deplete globotriaosylceramide and other glucosylceramide-based lipids in Fabry lymphocytes and were compared with N-butyldeoxynojirimycin, another reported glucosylceramide synthase inhibitor. RESULTS: Concentrations as low as 10 nmol/L of 4'-hydroxy-P4 and ethylenedioxy-P4 resulted in 70 and 80% depletion, respectively, of globotriaosylceramide, with maximal depletion occurring at three days of treatment. There was no impairment of cell growth. In contrast, N-butyldeoxynojirimycin only minimally lowered globotriaosylceramide levels, even at concentrations as high as 10 micromol/L. Globotriaosylceramide depletion was confirmed by the loss of binding of FITC-conjugated verotoxin B subunit to the lymphoblasts. CONCLUSIONS: These findings suggest that selective glucosylceramide synthase inhibitors are highly effective in the depletion of globotriaosylceramide from Fabry cell lines. We suggest that these compounds have potential therapeutic utility in the treatment of Fabry disease. (+info)
Twenty novel mutations in the alpha-galactosidase A gene causing Fabry disease.
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BACKGROUND: Fabry disease, an X-linked inborn error of glycosphingolipid catabolism, results from the deficient activity of the lysosomal exoglycohydrolase alpha-galactosidase A (EC 3.2.1.22; alpha-Gal A). The nature of the molecular lesions in the alpha-Gal A gene in 30 unrelated families was determined to provide precise heterozygote detection, prenatal diagnosis, and define genotype-phenotype correlations. MATERIALS AND METHODS: Genomic DNA was isolated from affected males and/or carrier females from 30 unrelated families with Fabry disease. The entire alpha-Gal A coding region and flanking intronic sequences were analyzed by PCR amplification and automated sequencing. RESULTS: Twenty new mutations were identified, each in a single family: C142R, G183D, S235C, W236L, D244H, P259L, M267I, I289F, Q321E, C378Y, C52X, W277X, IVS4(+4), IVS6(+2), IVS6(-1), 35del13, 256del1, 892ins1, 1176del4, and 1188del1. In the remaining 10 unrelated Fabry families, 9 previously reported mutations were detected: M42V, R112C, S148R, D165V, N215S (in 2 families), Q99X, C142X, R227X, and 1072del3. Haplotype analysis using markers closely flanking the alpha-Gal A gene indicated that the two patients with the N215S lesion were unrelated. The IVS4(+4) mutation was a rare intronic splice site mutation that causes Fabry disease. CONCLUSIONS: These studies further define the heterogeneity of mutations in the alpha-Gal A gene causing Fabry disease, permit precise heterozygote detection and prenatal diagnosis, and help delineate phenotype-genotype correlations in this disease. +info)
Clinicopathologic analysis of 124 biopsy-proven peripheral nerve diseases.
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We reviewed dinical, histological and ultrastructural findings of 124 cases of sural nerve biopsy specimens to delineate the trends of peripheral nerve diseases in our institute. Eighty-one were men and 43 were women. We categorized them into five groups: specific diagnosis (66 cases, 53.2%), axonal degeneration type (47 cases, 37.9%), demyelinating type (4 cases, 3.2%), mixed axonal degeneration-demyelinating type (6 cases, 4.8%) and normal (1 case, 0.9%). Cases with specific diagnosis included 21 inflammatory demyelinating polyneuropathy (15 chronic inflammatory demyelinating polyradiculoneuropathy, 6 Guillain-Barre disease), 13 hereditary motor and sensory neuropathy (7 Charcot-Marie-Tooth type I, 6 Charcot-Marie-Tooth type II), 10 vasculitis, 6 toxic neuropathy, 4 leprosy, 3 diabetic neuropathy, 2 alcoholic neuropathy, 1 Fabry's disease and other specific diseases (5 cases). In our cases, the proportion of specific diagnoses was higher, while the proportion of demyelinating peripheral neuropathies and normal were lower than those of Western series. The results of this study indicate that 1) a dose clinicopathologic correlation is important to make a precise diagnosis of peripheral nerve biopsy, 2) Biopsy under strict indication may reduce unnecessary histologic examination, 3) There is no difference in disease pattern of peripheral neuropathy between Western people and Koreans. (+info)
Characterization of two alpha-galactosidase mutants (Q279E and R301Q) found in an atypical variant of Fabry disease.
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The mutant products Q279E ((279)Gln to Glu) and R301Q ((301)Arg to Gln) of the X-chromosomal inherited alpha-galactosidase (EC 3.2.1. 22) gene, found in unrelated male patients with variant Fabry disease (late-onset cardiac form) were characterized. In contrast to patients with classic Fabry disease, who have no detectable alpha-galactosidase activity, atypical variants have residual enzyme activity. First, the properties of insect cell-derived recombinant enzymes were studied. The K(m) and V(max) values of Q279E, R301Q, and wild-type alpha-galactosidase toward an artificial substrate, 4-methylumbelliferyl-alpha-D-galactopyranoside, were almost the same. In order to mimic intralysosomal conditions, the degradation of the natural substrate, globotriaosylceramide, by the alpha-galactosidases was analyzed in a detergent-free-liposomal system, in the presence of sphingolipid activator protein B (SAP-B, saposin B). Kinetic analysis revealed that there was no difference in the degradative activity between the mutants and wild-type alpha-galactosidase activity toward the natural substrate. Then, immunotitration studies were carried out to determine the amounts of the mutant gene products naturally occurring in cells. Cultured lymphoblasts, L-57 (Q279E) and L-148 (R301Q), from patients with variant Fabry disease, and L-20 (wild-type) from a normal subject were used. The 50% precipitation doses were 7% (L-57) and 10% (L-148) of that for normal lymphoblast L-20, respectively. The residual alpha-galactosidase activity was 3 and 5% of the normal level in L-57 and L-148, respectively. The quantities of immuno cross-reacting materials roughly correlated with the residual alpha-galactosidase activities in lymphoblast cells from the patients. Compared to normal control cells, fibroblast cells from a patient with variant Fabry disease, Q279E mutation, secreted only small amounts of alpha-galactosidase activity even in the presence of 10 mM NH(4)Cl. It is concluded that Q279E and R301Q substitutions do not significantly affect the enzymatic activity, but the mutant protein levels are decreased presumably in the ER of the cells. (+info)