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R O Brady

Publications and source records attributed to R O Brady.

At least 19 recordsLinked to original sources
PubMed2006

Neuropathic and cerebrovascular correlates of hearing loss in Fabry disease.

Fabry disease, OMIM 301500, is a progressive multisystem storage disorder due to the deficiency of alpha-galactosidase A (GALA). Neurological and vascular manifestations of this disorder with regard to hearing loss have not been analysed quantitatively in large cohorts. We conducted a retrospective cross sectional analysis of hearing loss in 109 male and female patients with Fabry disease who were referred to and seen at the Clinical Center of the National Institutes of Health, Bethesda, MD, USA on natural history and enzyme replacement study protocols. There were 85 males aged 6-58 years (mean 31 years, SD 13) and 24 females aged 22-72 years (mean 42 years, SD 12). All patients underwent a comprehensive audiological evaluation. In addition, cerebral white matter lesions, peripheral neuropathy, and kidney function were quantitatively assessed. HL(95), defined as a hearing threshold above the 95th percentile for age and gender matched normal controls, was present in 56% [95% CI (42.2-67.2)] of the males. Prevalence of HL(95) was lower in the group of patients with residual GALA enzyme activity compared with those without detectable activity (33% versus 63%) HL(95) was present in the low-, mid- and high-frequency ranges for all ages. Male patients with HL(95) had a higher microvascular cerebral white matter lesion load [1.4, interquartile range (IQR) 0-30.1 +/- versus 0, IQR 0-0], more pronounced cold perception deficit [19.4 +/- 5.5 versus 13.5 +/- 5.5 of just noticeable difference (JND) units] and lower kidney function [creatinine: 1.6 +/- 1.2 versus 0.77 +/- 0.2 mg/dl; blood urea nitrogen (BUN): 20.1 +/- 14.1 versus 10.3 +/- 3.28 mg/dl] than those without HL(95) (P < 0.001). Of the females, 38% had HL(95). There was no significant association with cold perception deficit, creatinine or BUN in the females. Word recognition and acoustic reflexes analyses suggested a predominant cochlear involvement. We conclude that hearing loss involving all frequency regions significantly contributes to morbidity in patients with Fabry disease. Our quantitative analysis suggests a correlation of neuropathic and vascular damage with hearing loss in the males. Residual GALA activity appears to have a protective effect against hearing loss.

Adolescent↗
PubMed2006

Image-guided, direct convective delivery of glucocerebrosidase for neuronopathic Gaucher disease.

OBJECTIVE: To determine if convection-enhanced delivery (CED) of glucocerebrosidase could be used to treat targeted sites of disease progression in the brain and brainstem of a patient with neuronopathic Gaucher disease while monitoring enzyme distribution using MRI. METHODS: A CED paradigm in rodents (n = 8) and primates (n = 5) that employs co-infusion of a surrogate MRI tracer (gadolinium diethylenetriamine penta-acetic acid [Gd-DTPA]) with glucocerebrosidase to permit real-time monitoring of distribution was developed. The safety and feasibility of this delivery and monitoring paradigm were evaluated in a patient with type 2 Gaucher disease. RESULTS: Animal studies revealed that real-time, T1-weighted, MRI of Gd-DTPA accurately tracked enzyme distribution during CED. Targeted perfusion of clinically affected anatomic sites in a patient with neuronopathic Gaucher disease (frontal lobe and brainstem) with glucocerebrosidase was successfully performed. Real-time MRI revealed progressive and complete filling of the targeted region with enzyme and Gd-DTPA infusate. The patient tolerated the infusions without evidence of toxicity. CONCLUSIONS: Convection-enhanced delivery can be used to safely perfuse large regions of the brain and brainstem with therapeutic levels of glucocerebrosidase. Co-infused imaging surrogate tracers can be used to monitor and control the distribution of therapeutic agents in vivo. Patients with neuronopathic Gaucher disease and other intrinsic CNS disorders may benefit from a similar treatment paradigm.

Animals↗
PubMed2006

Efficient correction of Fabry mice and patient cells mediated by lentiviral transduction of hematopoietic stem/progenitor cells.

A deficiency in alpha-galactosidase A (alpha-gal A) activity causes Fabry disease. Virus-based delivery of genes can correct cells and establish a sustained supply of therapeutic proteins. Recombinant lentiviral vectors (LVs) show promise in this context. We first demonstrate LV-mediated marking of peripheral blood (PB) cells by transduction/transplantation of hematopoietic stem/progenitor cells. Stable enGFP expression was observed in PB for 37 weeks. Next, we transplanted Fabry mice with bone marrow mononuclear cells (BMMNCs) transduced a single time with a LV encoding the human alpha-gal A cDNA. Sustained expression of functional alpha-gal A in Fabry mice was observed over 24 weeks. Plasma alpha-gal A activity from treated Fabry mice was two-fold higher than wild-type controls. Increased alpha-gal A activity, often to supra-normal levels, and reduction of globotriaosylceramide, a glycolipid that accumulates in Fabry disease, was observed in all organs assessed. In secondary bone marrow transplantations, Fabry mice showed multilineage marking of PB, splenocytes and BMMNCs, along with therapeutic levels of alpha-gal A activity in plasma and organs over 20 weeks. Lastly, we transduced mobilized PB CD34(+) cells from a Fabry patient and observed corresponding enzymatic increases. Thus a single LV-mediated transduction of primitive hematopoietic cells can result in sustained correction for Fabry disease.

Animals↗
PubMed2004

Correlation between enzyme activity and substrate storage in a cell culture model system for Gaucher disease.

Gaucher disease, the most common sphingolipidosis, is caused by a decreased activity of glucosylceramide beta-glucosidase, resulting in the accumulation of glucosylceramide in macrophage-derived cells known as Gaucher cells. Much of the storage material is thought to originate from the turnover of cell membranes, such as phagocytosed red and white blood cells. In this study, an in vitro model of Gaucher disease was developed by treating the murine macrophage cell line J774 with a specific inhibitor of glucosylceramide beta-glucosidase, conduritol B-epoxide, and feeding red blood cell ghosts, in order to mimic the disease state. It was found in this model system that glucosylceramide beta-glucosidase activity could be reduced to about 11-15% of the normal control level before increased storage of glucosylceramide occurred. This in vitro system allows insight into the correlation between enzyme activity and lipid storage as predicted by the theory of residual enzyme activity that was proposed by Conzelmann and Sandhoff.

Animals↗
PubMed2003

Toxicity of glucosylsphingosine (glucopsychosine) to cultured neuronal cells: a model system for assessing neuronal damage in Gaucher disease type 2 and 3.

Patients with Gaucher disease have been classified as type 1 nonneuronopathic, type 2 acute neuronopathic, and type 3 chronic neuronopathic phenotypes. Increased quantities of glucocerebroside and glucosylsphingosine (glucopsychosine) are present in the brain of type 2 and type 3 Gaucher patients. Galactosylsphingosine has previously been shown to be neurotoxic in globoid cell leukodystrophy (Krabbe disease). To determine whether glucosylsphingosine is also neurotoxic, we examined its effect on cultured cholinergic neuron-like LA-N-2 cells. When these cells were exposed to 1, 5, or 10 microM glucosylsphingosine for a period of 18 h, they became shriveled, neurite outgrowth was suppressed, and the activities of the lysosomal enzymes glucocerebrosidase, sphingomyelinase, and beta-galactosidase were reduced in a dose-dependent manner. Acetylcholine in cells exposed to glucosylsphingosine also declined. Cells switched to glucosylsphingosine-free medium partially recovered. The data suggest that accumulation of glucosylsphingosine contributes to neuronal dysfunction and destruction in patients with neuronopathic Gaucher disease.

Acetylcholine↗
PubMed2003

Gaucher and Fabry diseases: from understanding pathophysiology to rational therapies.

UNLABELLED: Over the past 40 years there has been remarkable development in our understanding of the pathophysiology of lysosomal storage disorders. This review describes the research carried out on the sphingolipid storage disorders from the first demonstration of the underlying metabolic abnormality in Gaucher disease to the development of enzyme replacement therapy for Gaucher and Fabry diseases. Initial developments in gene therapy are also described. CONCLUSION: The introduction of enzyme replacement therapy has provided a lifeline for patients with Gaucher or Fabry disease. It is anticipated that future developments, including gene therapy, will provide additional therapeutic options.

Fabry Disease↗
PubMed2002

Uptake of mannose-terminal glucocerebrosidase in cultured human cholinergic and dopaminergic neuron cell lines.

Enzyme replacement therapy has been shown to be particularly effective for patients with type 1 (non-neuronopathic) Gaucher disease. However, intravenously administered glucocerebrosidase does not reverse or halt the progression of brain damage in patients with type 2 (acute neuronopathic) Gaucher disease. A previous investigation revealed that intracerebral infusion of mannose-terminal glucocerebrosidase was safe in experimental animals. The enzyme had a comparatively long half-life in the brain. It was transported by convection from the site of infusion along white matter fiber tracts to the cerebral cortex where it was endocytosed by neurons. In anticipation of intracerebral administration of mannose-terminal glucocerebrosidase to patients with type 2 Gaucher disease, it was important to learn the mechanism involved in its cellular uptake. We therefore compared the endocytosis of this enzyme by J774 macrophage cells with that in two human neuronal cell lines and a human astrocyte cell line. Mannose-terminal glucocerebrosidase was taken up by cholinergic LA-N-2 cells, but to a much lower extent than by macrophages. Considerably less of the enzyme was endocytosed by dopaminergic SH-SY5Y cells. It was not taken up by NHA astrocytes. The findings provide encouragement for an exploration of intracerebral administration of glucocerebrosidase in patients with type 2 Gaucher disease.

Acetylcholine↗
PubMed2001

Mutation analysis of the acid beta-glucosidase gene in a patient with type 3 Gaucher disease and neutralizing antibody to alglucerase.

The beneficial effects of macrophage-targeted glucocerebrosidase (alglucerase, Ceredase) in patients with Gaucher disease are well established. A minority of recipients develop transient non-neutralizing antibodies to the exogenous enzyme. A 7-year-old patient with type 3 Gaucher disease, whose clinical course began to deteriorate while receiving alglucerase developed a progressively increasing titer of IgG antibody, that blocked the catalytic activity of alglucerase. We investigated the acid beta-glucosidase genotype in this patient. Direct sequencing of both cDNA and genomic PCR products was used to characterize the mutations underlying acid beta-glucosidase deficiency. The patient was shown to be a compound heterozygote for a previously reported missense mutation (G377S), and a novel single nucleotide deletion (g5255delT). The transcript originating from the latter allele was undetectable in RT-PCR experiments. We report the first characterization of a GBA genotype associated with the development of neutralizing antibody to alglucerase, in a patient affected with type 3 Gaucher disease. Our results may help to shed light on the mechanisms underlying this phenomenon which, in the rare instances where it occurs, hampers the efficacy of enzyme replacement therapy.

Antibody Formation↗
PubMed2001

Regulation of NMDA receptors by cyclin-dependent kinase-5.

Members of the N-methyl-d-aspartate (NMDA) class of glutamate receptors (NMDARs) are critical for development, synaptic transmission, learning and memory; they are targets of pathological disorders in the central nervous system. NMDARs are phosphorylated by both serine/threonine and tyrosine kinases. Here, we demonstrate that cyclin dependent kinase-5 (Cdk5) associates with and phosphorylates NR2A subunits at Ser-1232 in vitro and in intact cells. Moreover, we show that roscovitine, a selective Cdk5 inhibitor, blocks both long-term potentiation induction and NMDA-evoked currents in rat CA1 hippocampal neurons. These results suggest that Cdk5 plays a key role in synaptic transmission and plasticity through its up-regulation of NMDARs.

Animals↗
PubMed2001

Regional cerebral hyperperfusion and nitric oxide pathway dysregulation in Fabry disease: reversal by enzyme replacement therapy.

BACKGROUND: Fabry disease is an X-linked lysosomal deficiency of alpha-galactosidase A that results in cellular accumulation of galacto-conjugates such as globotriosylceramide, particularly in blood vessels. It is associated with early-onset stroke and kidney and heart failure. METHODS AND RESULTS: Using [(15)O] H(2)O and PET, we found increased resting regional cerebral blood flow in Fabry disease without evidence of occlusive vasculopathy or cerebral hypoperfusion. Because nitric oxide is known to play an important role in vascular tone and reactivity, we studied plasma nitrate, nitrite, and low-molecular-weight S-nitrosothiol levels by chemiluminescence. Skin biopsy specimens and archived brain tissue were also examined immunohistochemically for nitrotyrosine. Plasma nitrate, nitrite, and low-molecular-weight S-nitrosothiol were in the normal range; however, enhanced nitrotyrosine staining was observed in dermal and cerebral blood vessels. After a double-blind, placebo-controlled trial of alpha-galactosidase A therapy, the resting regional cerebral blood flow in the treated group was significantly reduced, with a notable decrease of nitrotyrosine staining in dermal blood vessels. CONCLUSIONS: These findings suggest a chronic alteration of the nitric oxide pathway in Fabry disease, with critical protein nitration that is reversible with enzyme replacement therapy.

Adult↗
PubMed2001

Enzyme replacement therapy in Fabry disease: a randomized controlled trial.

CONTEXT: Fabry disease is a metabolic disorder without a specific treatment, caused by a deficiency of the lysosomal enzyme alpha-galactosidase A (alpha-gal A). Most patients experience debilitating neuropathic pain and premature mortality because of renal failure, cardiovascular disease, or cerebrovascular disease. OBJECTIVE: To evaluate the safety and efficacy of intravenous alpha-gal A for Fabry disease. DESIGN AND SETTING: Double-blind placebo-controlled trial conducted from December 1998 to August 1999 at the Clinical Research Center of the National Institutes of Health. PATIENTS: Twenty-six hemizygous male patients, aged 18 years or older, with Fabry disease that was confirmed by alpha-gal A assay. INTERVENTION: A dosage of 0.2 mg/kg of alpha-gal A, administered intravenously every other week (12 doses total). MAIN OUTCOME MEASURE: Effect of therapy on neuropathic pain while without neuropathic pain medications measured by question 3 of the Brief Pain Inventory (BPI). RESULTS: Mean (SE) BPI neuropathic pain severity score declined from 6.2 (0.46) to 4.3 (0.73) in patients treated with alpha-gal A vs no significant change in the placebo group (P =.02). Pain-related quality of life declined from 3.2 (0.55) to 2.1 (0.56) for patients receiving alpha-gal A vs 4.8 (0.59) to 4.2 (0.74) for placebo (P =.05). In the kidney, glomeruli with mesangial widening decreased by a mean of 12.5% for patients receiving alpha-gal vs a 16.5% increase for placebo (P =.01). Mean inulin clearance decreased by 6.2 mL/min for patients receiving alpha-gal A vs 19.5 mL/min for placebo (P =.19). Mean creatinine clearance increased by 2.1 mL/min (0.4 mL/s) for patients receiving alpha-gal A vs a decrease of 16.1 mL/min (0.3 mL/s) for placebo (P =.02). In patients treated with alpha-gal A, there was an approximately 50% reduction in plasma glycosphingolipid levels, a significant improvement in cardiac conduction, and a significant increase in body weight. CONCLUSION: Intravenous infusions of alpha-gal A are safe and have widespread therapeutic efficacy in Fabry disease.

Adult↗
PubMed2001

Preselective gene therapy for Fabry disease.

Fabry disease is a lipid storage disorder resulting from mutations in the gene encoding the enzyme alpha-galactosidase A (alpha-gal A; EC ). We previously have demonstrated long-term alpha-gal A enzyme correction and lipid reduction mediated by therapeutic ex vivo transduction and transplantation of hematopoietic cells in a mouse model of Fabry disease. We now report marked improvement in the efficiency of this gene-therapy approach. For this study we used a novel bicistronic retroviral vector that engineers expression of both the therapeutic alpha-gal A gene and the human IL-2Ralpha chain (huCD25) gene as a selectable marker. Coexpression of huCD25 allowed selective immunoenrichment (preselection) of a variety of transduced human and murine cells, resulting in enhanced intracellular and secreted alpha-gal A enzyme activities. Of particular significance for clinical applicability, mobilized CD34(+) peripheral blood hematopoietic stem/progenitor cells from Fabry patients have low-background huCD25 expression and could be enriched effectively after ex vivo transduction, resulting in increased alpha-gal A activity. We evaluated effects of preselection in the mouse model of Fabry disease. Preselection of transduced Fabry mouse bone marrow cells elevated the level of multilineage gene-corrected hematopoietic cells in the circulation of transplanted animals and improved in vivo enzymatic activity levels in plasma and organs for more than 6 months after both primary and secondary transplantation. These studies demonstrate the potential of using a huCD25-based preselection strategy to enhance the clinical utility of ex vivo hematopoietic stem/progenitor cell gene therapy of Fabry disease and other disorders.

3T3 Cells↗
PubMed2001

Adeno-associated viral vector-mediated gene transfer results in long-term enzymatic and functional correction in multiple organs of Fabry mice.

Fabry disease is a lysosomal storage disorder caused by a deficiency of the lysosomal enzyme alpha-galactosidase A (alpha-gal A). This enzyme deficiency leads to impaired catabolism of alpha-galactosyl-terminal lipids such as globotriaosylceramide (Gb3). Patients develop painful neuropathy and vascular occlusions that progressively lead to cardiovascular, cerebrovascular, and renal dysfunction and early death. Although enzyme replacement therapy and bone marrow transplantation have shown promise in the murine analog of Fabry disease, gene therapy holds a strong potential for treating this disease in humans. Delivery of the normal alpha-gal A gene (cDNA) into a depot organ such as liver may be sufficient to elicit corrective circulating levels of the deficient enzyme. To investigate this possibility, a recombinant adeno-associated viral vector encoding human alpha-gal A (rAAV-AGA) was constructed and injected into the hepatic portal vein of Fabry mice. Two weeks postinjection, alpha-gal A activity in the livers of rAAV-AGA-injected Fabry mice was 20-35% of that of the normal mice. The transduced animals continued to show higher alpha-gal A levels in liver and other tissues compared with the untouched Fabry controls as long as 6 months after treatment. In parallel to the elevated enzyme levels, we see significant reductions in Gb3 levels to near normal at 2 and 5 weeks posttreatment. The lower Gb3 levels continued in liver, spleen, and heart, up to 25 weeks with no significant immune response to the virus or alpha-gal A. Also, no signs of liver toxicity occurred after the rAAV-AGA administration. These findings suggest that an AAV-mediated gene transfer may be useful for the treatment of Fabry disease and possibly other metabolic disorders.

Animals↗
PubMed2001

Synergistic contributions of cyclin-dependant kinase 5/p35 and Reelin/Dab1 to the positioning of cortical neurons in the developing mouse brain.

Cyclin-dependent kinase (Cdk) 5 is a unique member of the Cdk family, because Cdk5 kinase activity is detected only in the nervous tissue. Two neuron-specific activating subunits of Cdk5, p35 and p39, have been identified. Overlapping expression pattern of these isoforms in the embryonic mouse brain and the significant residual Cdk5 kinase activity in brain homogenate of the p35-/- mice indicate the redundant functions of the Cdk5 activators in vivo. Severe neuronal migration defects in p35-/-Cdk5 +/- mice further support the idea that the redundant expression of the Cdk5 activators may cause a milder phenotype in p35-/- mice compared with Cdk5-/- mice. Mutant mice lacking either Cdk5 or p35 exhibit certain similarities with Reelin/Dab1-mutant mice in the disorganization of cortical laminar structure in the brain. To elucidate the relationship between Cdk5/p35 and Reelin/Dab1 signaling, we generated mouse lines that have combined defects of these genes. The addition of heterozygosity of either Dab1 or Reelin mutation to p35-/- causes the extensive migration defects of cortical neurons in the cerebellum. In the double-null mice of p35 and either Dab1 or Reelin, additional migration defects occur in the Purkinje cells in the cerebellum and in the pyramidal neurons in the hippocampus. These additional defects in neuronal migration in mice lacking both Cdk5/p35 and Reelin/Dab1 indicate that Cdk5/p35 may contribute synergistically to the positioning of the cortical neurons in the developing mouse brain.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Neuronal cyclin-dependent kinase 5 activity is critical for survival.

Cyclin-dependent kinase 5 (Cdk5) null mice exhibit a unique phenotype characterized by perinatal mortality, disrupted cerebral cortical layering attributable to abnormal neuronal migration, lack of cerebellar foliation, and chromatolytic changes of neurons in the brainstem and the spinal cord. Because Cdk5 is expressed in both neurons and astrocytes, it has been unclear whether this phenotype is primarily attributable to defects in neurons or in astrocytes. Herein we report reconstitution of Cdk5 expression in neurons in Cdk5 null mice and its effect on the null phenotype. Unlike the Cdk5 null mice, the reconstituted Cdk5 null mice that express the Cdk5 transgene under the p35 promoter (TgKO mice) were viable and fertile. Because Cdk5 expression is mainly limited to neurons in these mice and rescues the defects in the nervous system of the Cdk5 null phenotype, it clearly demonstrates that Cdk5 activity is necessary for normal development and survival of p35-expressing neurons.

Animals↗
PubMed2001

Systematic approach to the diagnosis of lysosomal storage disorders.

Disorders that arise as a result of lysosomal dysfunction represent some of the most challenging diagnostic problems in medicine. Not only are these disorders infrequently seen, but they may also present with signs and symptoms that mimic perinatal injury, food intolerance, or the sequellae of neonatal infection. Misidentification can lead to significant delay in diagnosis. Ironically, as the prevailing economic climate places increasing time constraints on practicing physicians, medical research is providing treatment strategies and management techniques that are most effective if applied early in the course of the disease. Most lysosomal storage disorders can now be definitively diagnosed once the signs are recognized. In many cases the benefits of early diagnosis, enlightened management, and appropriate referral are considerable. The aim of this paper is to demystify this elusive class of diseases, to promote clinical vigilance in their detection, and to provide a systematic approach to diagnosis when clinical suspicion is aroused.

Gangliosides↗
PubMed2001

Enzyme replacement therapy in Fabry disease.

Recent clinical trials have demonstrated that enzyme replacement therapy with alpha-galactosidase A (alpha-Gal A) constitutes a major clinical advance in the treatment of patients with Fabry disease. This new therapeutic approach has been shown to be well tolerated and effective in reducing levels of the storage product globotriaosylceramide and in normalizing many of the debilitating manifestations of the disorder. A double-blind placebo-controlled trial in 26 hemizygous male patients showed that agalsidase alfa (human alpha-Gal A) significantly reduced neuropathic pain (p = 0.02), increased creatinine clearance (p = 0.02), improved glomerular histology, reduced the QRS interval on electrocardiography and increased weight gain. Positron emission tomography also revealed normalization of cerebrovascular flow. After the 6-month controlled period, all patients were given agalsidase alfa for a further 12 months. At the end of this period, all patients had a decrease in neuropathic pain, and there was a significant improvement in their ability to sense heat and cold. In addition, renal function stabilized, even in patients with renal insufficiency at the onset of treatment, and patients reported a normalization of sweating and improvements in their level of energy and sense of well-being. These findings show that enzyme replacement therapy offers promise as an effective management strategy for patients with Fabry disease.

Animals↗