scholarly journals Quantitative estimation of lysosomal storage in mucopolysaccharidoses by electron microscopy analysis.

2012 ◽  
Vol 59 (4) ◽  
Author(s):  
Magdalena Narajczyk ◽  
Marta Moskot ◽  
Aleksandra Konieczna
Keyword(s):  
Electron Microscopy ◽  
Quantitative Estimation ◽  
Physiological State ◽  
Substrate Reduction Therapy ◽  
Lysosomal Storage ◽  
Electron Microscopic ◽  
Enzyme Replacement ◽  
Substrate Reduction ◽  
Electron Microscopy Analysis ◽  
Severity Of The Disease

Mucopolysaccharidoses (MPS) are severe inherited metabolic disorders caused by storage of glycosaminoglycans (GAGs). The level of accumulated GAGs is an important parameter in assessment of the severity of the disease and the efficacy of treatment; unfortunately, biochemical methods are often unreliable and only semi-quantitative. Therefore, finding other methods for estimation of GAG levels and/or assessment of the efficacy of applied therapy is very important. Although monitoring of GAG levels during therapy is crucial, in this work it is proposed that analysis of the ultrastructure of MPS cells by electron microscopic techniques can be considered as an alternative and reliable method for assessment of lysosomal storage. The number of complex lysosomal structures was found to be significantly higher in MPS cells relative to controls, while it decreased significantly in response to either enzyme replacement therapy or substrate reduction therapy. Thus, this parameter, easily assessed by electron microscopy, appears to correspond to the physiological state of MPS cells.

Treatments for lysosomal storage disorders

2010 ◽  
Vol 38 (6) ◽  
pp. 1465-1468 ◽  
Author(s):  
Robin Lachmann
Keyword(s):  
Genetic Disorders ◽  
Lysosomal Storage Disorders ◽  
Substrate Reduction Therapy ◽  
Lysosomal Storage ◽  
Enzyme Replacement ◽  
Haemopoietic Stem Cell ◽  
Substrate Reduction ◽  
Haemopoietic Stem Cell Transplantation ◽  
Late Stages ◽  
Storage Disorders

There are over 70 human diseases that are caused by defects in various aspects of lysosomal function. Until 20 years ago, the only specific therapy available for lysosomal storage disorders was allogeneic haemopoietic stem cell transplantation. Over the last two decades, there has been remarkable progress and there are now licensed treatments for seven of these diseases. In some cases, a choice of agents is available. For selected enzyme-deficiency disordes, ERT (enzyme-replacement therapy) has proved to be highly effective. In other cases, ERT has been less impressive, and it seems that it is not possible to efficiently deliver recombinant enzyme to all tissues. These difficulties have led to the development of other small-molecule-based therapies, and a drug for SRT (substrate-reduction therapy) is now licensed and potential chaperone molecules for ERT are in the late stages of clinical development. Nonetheless, there is still significant unmet clinical need, particularly when it comes to treating LSDs which affect the brain. LSDs have led the way in the development of treatment for genetic disorders, and it seems likely that there will be further therapeutic innovations in the future.

scholarly journals Substrate reduction therapy: clinical evaluation in type 1 Gaucher disease

2003 ◽  
Vol 358 (1433) ◽  
pp. 955-960 ◽  
Author(s):  
Chris Moyses
Keyword(s):  
Gaucher Disease ◽  
Clinical Manifestations ◽  
Residual Activity ◽  
Substrate Reduction Therapy ◽  
Lysosomal Storage ◽  
Enzyme Replacement ◽  
Substrate Reduction ◽  
Clinical Consequences ◽  
Type 1 Gaucher Disease

Glycosphingolipid (GSL) lysosomal storage disorders are inherited enzyme deficiencies that result in pathological lysosomal accumulation of glycolipids, with widespread clinical consequences. Type 1 Gaucher disease is the commonest of these; the deficient enzyme in this condition is glucocerebrosidase. Clinical manifestations include hepatosplenomegaly, thrombocytopenia, anaemia, recurrent infections and skeletal lesions. The condition can be treated with intravenous enzyme replacement therapy (ERT). Substrate reduction therapy is a new approach in which glycolipid accumulation is counteracted not by replacing the deficient enzyme but by reducing the substrate level to better balance residual activity of the deficient enzyme. Miglustat is an inhibitor of glucosylceramide synthase, a key enzyme in GSL synthesis. Oral administration of miglustat to patients with type 1 Gaucher disease attenuates the synthesis of glucocerebroside, the substrate of the deficient glucocerebrosidase. In the first clinical study, patients with type 1 Gaucher disease who had enlargement of the liver or spleen and (if present) the spleen at baseline received 12 months treatment with oral miglustat. There were mean decreases in liver and spleen volumes of 12% (7.9–16.4, p < 0.001) and 19% (14.3–23.7, p < 0.001), respectively. Mean haemoglobin increased by 0.26 g dl −1 (−0.5−0.57, not statistically significant) and platelet count by 8.3 × 10 9 l −1 (1.9–14.7, p = 0.014).

scholarly journals Fabry Disease: Molecular Basis, Pathophysiology, Diagnostics and Potential Therapeutic Directions

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 271
Author(s):  
Ken Kok ◽  
Kimberley C. Zwiers ◽  
Rolf G. Boot ◽  
Hermen S. Overkleeft ◽  
Johannes M. F. G. Aerts ◽  
...  
Keyword(s):  
Fabry Disease ◽  
Molecular Basis ◽  
Diagnostic Procedures ◽  
Neurological Complications ◽  
Substrate Reduction Therapy ◽  
Lysosomal Storage ◽  
Pharmacological Chaperone ◽  
Enzyme Replacement ◽  
Substrate Reduction ◽  
Timely Treatment

Fabry disease (FD) is a lysosomal storage disorder (LSD) characterized by the deficiency of α-galactosidase A (α-GalA) and the consequent accumulation of toxic metabolites such as globotriaosylceramide (Gb3) and globotriaosylsphingosine (lysoGb3). Early diagnosis and appropriate timely treatment of FD patients are crucial to prevent tissue damage and organ failure which no treatment can reverse. LSDs might profit from four main therapeutic strategies, but hitherto there is no cure. Among the therapeutic possibilities are intravenous administered enzyme replacement therapy (ERT), oral pharmacological chaperone therapy (PCT) or enzyme stabilizers, substrate reduction therapy (SRT) and the more recent gene/RNA therapy. Unfortunately, FD patients can only benefit from ERT and, since 2016, PCT, both always combined with supportive adjunctive and preventive therapies to clinically manage FD-related chronic renal, cardiac and neurological complications. Gene therapy for FD is currently studied and further strategies such as substrate reduction therapy (SRT) and novel PCTs are under investigation. In this review, we discuss the molecular basis of FD, the pathophysiology and diagnostic procedures, together with the current treatments and potential therapeutic avenues that FD patients could benefit from in the future.

Treatment for Lysosomal Storage Disorders

2020 ◽  
Vol 26 (40) ◽  
pp. 5110-5118
Author(s):  
Jayesh Sheth ◽  
Aadhira Nair
Keyword(s):  
Transmembrane Protein ◽  
Treatment Strategies ◽  
Lysosomal Storage Disorders ◽  
Substrate Reduction Therapy ◽  
Lysosomal Storage ◽  
Enzyme Replacement ◽  
Substrate Reduction ◽  
Organ Systems ◽  
Disease Condition ◽  
Storage Disorders

: Lysosomal storage disorders comprise a group of approximately 70 types of inherited diseases resulting due to lysosomal gene defects. The outcome of the defect is a deficiency in either of the three: namely, lysosomal enzymes, activator protein, or transmembrane protein, as a result of which there is an unwanted accumulation of biomolecules inside the lysosomes. The pathophysiology of these conditions is complex affecting several organ systems and nervous system involvement in a majority of cases. Several research studies have well elucidated the mechanism underlying the disease condition leading to the development in devising the treatment strategies for the same. Currently, these approaches aim to reduce the severity of symptoms or delay the disease progression but do not provide a complete cure. The main treatment methods include Enzyme replacement therapy, Bone marrow transplantation, Substrate reduction therapy, use of molecular chaperones, and Gene therapy. This review article presents an elaborate description of these strategies and discusses the ongoing studies for the same.

scholarly journals Fabry Disease Therapy: State-of-the-Art and Current Challenges

2020 ◽  
Vol 22 (1) ◽  
pp. 206
Author(s):  
Olga Azevedo ◽  
Miguel Fernandes Gago ◽  
Gabriel Miltenberger-Miltenyi ◽  
Nuno Sousa ◽  
Damião Cunha
Keyword(s):  
Fabry Disease ◽  
State Of The Art ◽  
Large Body ◽  
Real Life ◽  
Clinical Manifestations ◽  
Substrate Reduction Therapy ◽  
Lysosomal Storage ◽  
New Therapies ◽  
Enzyme Replacement

Fabry disease (FD) is a lysosomal storage disorder caused by mutations of the GLA gene that lead to a deficiency of the enzymatic activity of α-galactosidase A. Available therapies for FD include enzyme replacement therapy (ERT) (agalsidase alfa and agalsidase beta) and the chaperone migalastat. Despite the large body of literature published about ERT over the years, many issues remain unresolved, such as the optimal dose, the best timing to start therapy, and the clinical impact of anti-drug antibodies. Migalastat was recently approved for FD patients with amenable GLA mutations; however, recent studies have raised concerns that “in vitro” amenability may not always reflect “in vivo” amenability, and some findings on real-life studies have contrasted with the results of the pivotal clinical trials. Moreover, both FD specific therapies present limitations, and the attempt to correct the enzymatic deficiency, either by enzyme exogenous administration or enzyme stabilization with a chaperone, has not shown to be able to fully revert FD pathology and clinical manifestations. Therefore, several new therapies are under research, including new forms of ERT, substrate reduction therapy, mRNA therapy, and gene therapy. In this review, we provide an overview of the state-of-the-art on the currently approved and emerging new therapies for adult patients with FD.

scholarly journals Small–molecule therapeutics for the treatment of glycolipid lysosomal storage disorders

2003 ◽  
Vol 358 (1433) ◽  
pp. 927-945 ◽  
Author(s):  
Terry D. Butters ◽  
Howard R. Mellor ◽  
Keishi Narita ◽  
Raymond A. Dwek ◽  
Frances M. Platt
Keyword(s):  
Catalytic Activity ◽  
Lysosomal Storage Disorders ◽  
Substrate Reduction Therapy ◽  
Lysosomal Storage ◽  
Substrate Reduction ◽  
Treatment Demand ◽  
Small Molecule Therapeutics ◽  
Storage Disorders

Glycosphingolipid (GSL) lysosomal storage disorders are a small but challenging group of human diseases to treat. Although these disorders appear to be monogenic in origin, where the catalytic activity of enzymes in GSL catabolism is impaired, the clinical presentation and severity of disease are heterogeneous. Present attitudes to treatment demand individual therapeutics designed to match the specific disease–related gene defect; this is an acceptable approach for those diseases with high frequency, but it lacks viability for extremely rare conditions. An alternative therapeutic approach termed ‘substrate deprivation’ or ‘substrate reduction therapy’ (SRT) aims to balance cellular GSL biosynthesis with the impairment in catalytic activity seen in lysosomal storage disorders. The development of N–alkylated iminosugars that have inhibitory activity against the first enzyme in the pathway for glucosylating sphingolipid in eukaryotic cells, ceramide–specific glucosyltransferase, offers a generic therapeutic for the treatment of all glucosphingolipidoses. The successful use of N–alkylated iminosugars to establish SRT as an alternative therapeutic strategy has been demonstrated in in vitro , in vivo and in clinical trials for type 1 Gaucher disease. The implications of these studies and the prospects of improvement to the design of iminosugar compounds for treating Gaucher and other GSL lysosomal storage disorders will be discussed.

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