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A retrospective review of the natural course of Mucopolysaccharidosis VII
Abstracts
9 months (Open-Label Period). Efficacy assessments include the changes from baseline in spleen and liver volumes, hemoglobin, platelets, skeletal manifestations, disease-related biomarkers, Gaucher assessments, and quality of life. Safety monitoring includes adverseevent reporting (severity, intensity, treatment-relatedness), scheduled laboratory and electrocardiographic evaluations, and physical examination. Results after 9 months of treatment with eliglustat will be available for presentation.
doi:10.1016/j.ymgme.2012.11.171
158 The development and evaluation of a macrophage model of Gaucher disease Nima Moavena, Elma Aflakib, Barbara K. Stubblefieldc, Grisel Lopezb, Emerson Maniwangb, Wendy Westbroekb, Nahid Tayebib, Juan Maruganc, Ellen Sidranskyb, aNational Institute of Health (NIH), National Human Genome Research Institute (NHGRI), Bethesda, MD, USA, bSection of Molecular Neurogenetics, Medical Genetics Branch, NHGRI, NIH, Bethesda, USA, cNIH Chemical Genomics Center NCATS, NIH, Rockville, USA Gaucher disease (GD), the most prevalent lysosomal storage disorder, is caused by mutations in GBA1, the gene encoding glucocerebrosidase (GCase). The disease is characterized by glucosylceramide (GlcCer)-laden macrophages in the liver, spleen and bone-marrow. Although in GD the GCase deficiency exists in all cell types, the phenotype manifests primarily in macrophages. GD presents with a wide range of symptoms with varying severity, and primarily affects skeletal, hematologic and nervous systems. However, the exact mechanism of GlcCer accumulation and its effect on macrophage function is still unresolved. We studied macrophages from 16 patients with type 1 GD and generated iPS-derived macrophages from a patient with type 2 GD. Peripheral monocytes were cultured and differentiated into macrophages. Lipid storage, demonstrated using bodipy-GlcCer, and glucosylsphingosine (GluSph), measured by fluorescence and LC– MS techniques, were increased. When cultured cells from patients with GD were fed lipid-laden red cell ghosts and/or fluorescence-labeled bodipy-GlcCer, we observed a dramatic increase in lipid storage, not seen in control macrophages. Using antibody to Lamp-2, we showed the accumulation was lysosomal. Following the expression of FcgammaRI/II in Gaucher macrophages by flow cytometry, we found that these cells demonstrated efficient phagocytosis. We also evaluated efferocytosis, the phagocytosis of dead cells, and found that Gaucher macrophages had an impaired efferocytotic index, which was b40% that of nonGaucher macrophages. Moreover, intracellular levels of reactive oxygen species (ROS) were significantly lower in Gaucher macrophages. These abnormalities were corrected both by the administration of purified recombinant glucocerebrosidase and a new chemical chaperone molecule under development. Thus, our patient derived macrophages are an appropriate and long-needed model to demonstrate the ability of different therapies to effectively reduce disease pathology in GD.
doi:10.1016/j.ymgme.2012.11.172
159 A retrospective review of the natural course of Mucopolysaccharidosis VII Adriana Montaño, William Sly, Saint Louis University - School of Medicine, St Louis, MO, USA
S67
Mucopolysaccharidosis VII (MPS VII; Sly syndrome) is a lysosomal storage disorder caused by the deficiency of -glucuronidase (GUS). MPS VII causes hepatosplenomegaly, pulmonary and cardiac disease, and dysostosis multiplex. To understand the natural history of MPS VII, extensive knowledge of the spectrum of disease severity, the rate of progression and distribution of specific symptoms in untreated patients with MPS VII is needed. In this study, we will investigate the natural progression of the disease and its severity and potential clinical endpoints via a retrospective review of all known MPS VII cases. To date, 71 patients from 21 countries were analyzed. Of these, 37 patients were classified with non-immune infantile hydrops and 34 patients had an infantile or adolescent form of the disease. Most patients with nonimmune infantile hydrops were diagnosed during pregnancy, some as early as 20 weeks of gestation, with hydrops fetalis and GUS deficiency. Some patients survived only a few months and died from respiratory, renal or cardiac insufficiencies. A few improved and thereafter resembled late onset forms. Patients with the infantile or adolescent forms of the disease had symptoms one or two years before diagnosis. This retrospective review of the clinical manifestations of MPS VII disease represents the largest analysis to date of the natural history of MPS VII disease in terms of onset, diagnosis, and heterogeneity of the disease progression, severity, and outcome. We will present our findings from this study and discuss the manifestation of the disease, potential clinical endpoints and therapeutic approaches. doi:10.1016/j.ymgme.2012.11.173
160 Effect of miglustat on bone remodeling in vitro in a low bone density mouse model Adriana Montaño, Ege Ozdemir, David Lee, Saint Louis University, School of Medicine, St Louis, MO, USA Gaucher disease is a lysosomal storage disease caused by the deficiency of beta-glucocerebrosidase (EC 3.2.1.45), encoded by the human GBA1 gene. Major clinical symptoms for these patients include hepatosplenomegaly, hematologic problems, and low bone density. Current treatment of the disease involves a choice among enzyme replacement therapy, substrate reduction therapy (ERT) and stem cell transplantation. Miglustat, an inhibitor of glucosylceramide synthase, is administrated orally and decreases the metabolic production of the accumulating substrate. Miglustat has been shown clinically to alleviate the symptoms associated with Gaucher disease, and unlike ERT, has been shown to increase bone mineralization over a shorter time course. However, the mechanism through which bone remineralization occurs with Miglustat is unknown and was the focus of this investigation. The aim of this study was to understand the role of Miglustat in the bone remodeling process through the analysis of gene expression markers of in a low bone density mouse model of in vitro. The analysis of expression markers associated with osteoclasts and osteoblasts were compared between hypophosphatasia and wild type mice cells treated with Miglustat. Gene candidates were identified based on a minimum two-fold increase or decrease in expression of a gene between groups. Our findings suggest that osteoclasts treated with Miglustat exhibited an under-expression of metaloproteinases (i.e. MMP2 and MMP8), and over-expression of a protease inhibitor which may explain the rapid ability of bone remineralization in patients treated with this drug. We will discuss the implications of our findings as a possible treatment to improve bone mineralization. doi:10.1016/j.ymgme.2012.11.174
9 months (Open-Label Period). Efficacy assessments include the changes from baseline in spleen and liver volumes, hemoglobin, platelets, skeletal manifestations, disease-related biomarkers, Gaucher assessments, and quality of life. Safety monitoring includes adverseevent reporting (severity, intensity, treatment-relatedness), scheduled laboratory and electrocardiographic evaluations, and physical examination. Results after 9 months of treatment with eliglustat will be available for presentation.
doi:10.1016/j.ymgme.2012.11.171
158 The development and evaluation of a macrophage model of Gaucher disease Nima Moavena, Elma Aflakib, Barbara K. Stubblefieldc, Grisel Lopezb, Emerson Maniwangb, Wendy Westbroekb, Nahid Tayebib, Juan Maruganc, Ellen Sidranskyb, aNational Institute of Health (NIH), National Human Genome Research Institute (NHGRI), Bethesda, MD, USA, bSection of Molecular Neurogenetics, Medical Genetics Branch, NHGRI, NIH, Bethesda, USA, cNIH Chemical Genomics Center NCATS, NIH, Rockville, USA Gaucher disease (GD), the most prevalent lysosomal storage disorder, is caused by mutations in GBA1, the gene encoding glucocerebrosidase (GCase). The disease is characterized by glucosylceramide (GlcCer)-laden macrophages in the liver, spleen and bone-marrow. Although in GD the GCase deficiency exists in all cell types, the phenotype manifests primarily in macrophages. GD presents with a wide range of symptoms with varying severity, and primarily affects skeletal, hematologic and nervous systems. However, the exact mechanism of GlcCer accumulation and its effect on macrophage function is still unresolved. We studied macrophages from 16 patients with type 1 GD and generated iPS-derived macrophages from a patient with type 2 GD. Peripheral monocytes were cultured and differentiated into macrophages. Lipid storage, demonstrated using bodipy-GlcCer, and glucosylsphingosine (GluSph), measured by fluorescence and LC– MS techniques, were increased. When cultured cells from patients with GD were fed lipid-laden red cell ghosts and/or fluorescence-labeled bodipy-GlcCer, we observed a dramatic increase in lipid storage, not seen in control macrophages. Using antibody to Lamp-2, we showed the accumulation was lysosomal. Following the expression of FcgammaRI/II in Gaucher macrophages by flow cytometry, we found that these cells demonstrated efficient phagocytosis. We also evaluated efferocytosis, the phagocytosis of dead cells, and found that Gaucher macrophages had an impaired efferocytotic index, which was b40% that of nonGaucher macrophages. Moreover, intracellular levels of reactive oxygen species (ROS) were significantly lower in Gaucher macrophages. These abnormalities were corrected both by the administration of purified recombinant glucocerebrosidase and a new chemical chaperone molecule under development. Thus, our patient derived macrophages are an appropriate and long-needed model to demonstrate the ability of different therapies to effectively reduce disease pathology in GD.
doi:10.1016/j.ymgme.2012.11.172
159 A retrospective review of the natural course of Mucopolysaccharidosis VII Adriana Montaño, William Sly, Saint Louis University - School of Medicine, St Louis, MO, USA
S67
Mucopolysaccharidosis VII (MPS VII; Sly syndrome) is a lysosomal storage disorder caused by the deficiency of -glucuronidase (GUS). MPS VII causes hepatosplenomegaly, pulmonary and cardiac disease, and dysostosis multiplex. To understand the natural history of MPS VII, extensive knowledge of the spectrum of disease severity, the rate of progression and distribution of specific symptoms in untreated patients with MPS VII is needed. In this study, we will investigate the natural progression of the disease and its severity and potential clinical endpoints via a retrospective review of all known MPS VII cases. To date, 71 patients from 21 countries were analyzed. Of these, 37 patients were classified with non-immune infantile hydrops and 34 patients had an infantile or adolescent form of the disease. Most patients with nonimmune infantile hydrops were diagnosed during pregnancy, some as early as 20 weeks of gestation, with hydrops fetalis and GUS deficiency. Some patients survived only a few months and died from respiratory, renal or cardiac insufficiencies. A few improved and thereafter resembled late onset forms. Patients with the infantile or adolescent forms of the disease had symptoms one or two years before diagnosis. This retrospective review of the clinical manifestations of MPS VII disease represents the largest analysis to date of the natural history of MPS VII disease in terms of onset, diagnosis, and heterogeneity of the disease progression, severity, and outcome. We will present our findings from this study and discuss the manifestation of the disease, potential clinical endpoints and therapeutic approaches. doi:10.1016/j.ymgme.2012.11.173
160 Effect of miglustat on bone remodeling in vitro in a low bone density mouse model Adriana Montaño, Ege Ozdemir, David Lee, Saint Louis University, School of Medicine, St Louis, MO, USA Gaucher disease is a lysosomal storage disease caused by the deficiency of beta-glucocerebrosidase (EC 3.2.1.45), encoded by the human GBA1 gene. Major clinical symptoms for these patients include hepatosplenomegaly, hematologic problems, and low bone density. Current treatment of the disease involves a choice among enzyme replacement therapy, substrate reduction therapy (ERT) and stem cell transplantation. Miglustat, an inhibitor of glucosylceramide synthase, is administrated orally and decreases the metabolic production of the accumulating substrate. Miglustat has been shown clinically to alleviate the symptoms associated with Gaucher disease, and unlike ERT, has been shown to increase bone mineralization over a shorter time course. However, the mechanism through which bone remineralization occurs with Miglustat is unknown and was the focus of this investigation. The aim of this study was to understand the role of Miglustat in the bone remodeling process through the analysis of gene expression markers of in a low bone density mouse model of in vitro. The analysis of expression markers associated with osteoclasts and osteoblasts were compared between hypophosphatasia and wild type mice cells treated with Miglustat. Gene candidates were identified based on a minimum two-fold increase or decrease in expression of a gene between groups. Our findings suggest that osteoclasts treated with Miglustat exhibited an under-expression of metaloproteinases (i.e. MMP2 and MMP8), and over-expression of a protease inhibitor which may explain the rapid ability of bone remineralization in patients treated with this drug. We will discuss the implications of our findings as a possible treatment to improve bone mineralization. doi:10.1016/j.ymgme.2012.11.174