Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Current human gene therapy relies on genetic modification of the patient's own cells. An alternate non-autologous approach is to use universal cell lines engineered to secrete therapeutic products. Protection with immuno-isolation devices would allow the same recombinant cell line to be used for different patients, thus potentially lowering the cost of treatment. The feasibility of this idea has now been demonstrated in vitro and in vivo. Recombinant gene products with potential therapeutic applications (human growth hormone, factor IX, lysosomal enzymes, adenosine deaminase) have been expressed from genetically modified cells after encapsulation with alginate-poly-L-lysine-alginate or hydroxyethyl methacrylate-methyl methacrylate. We have also demonstrated the feasibility of this idea in vivo. After intraperitoneal implantation, genetically modified mouse Ltk- fibroblasts or C2C12 myoblasts encapsulated in alginate-poly-L-lysine-alginate could deliver recombinant gene products (human growth hormone, human factor IX) to the systemic circulation of mice. The clinical efficacy of this novel approach to gene therapy has now been shown in murine models of human diseases. In the Snell dwarf mice deficient in growth hormone production, implantation of encapsulated mouse myoblasts engineered to secrete mouse growth hormone resulted in increases in body weight, length and organ sizes, some to > 25% above those of the controls. In the Gus/Gus mice suffering from the lysosomal storage disease mucopolysaccharidosis type VII due to deficient beta-glucuronidase, implantation of encapsulated mouse fibroblasts engineered to secrete mouse beta-glucuronidase resulted in delivery of normal levels of the enzyme in the plasma and significant correction of the organ histopathology. Hence, delivery of recombinant gene products through bioartificial devices appears to be a promising strategy for the treatment of genetic diseases.
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PMID:Microcapsules as bio-organs for somatic gene therapy. 961 35

Microencapsulation of recombinant "universal" cells with immunoprotective membranes is an alternate approach to somatic gene therapy. Therapeutic gene products secreted by these cells can be delivered to different patients without immunosuppression or genetic modification of the host's cells. The encapsulation of different mammalian cell types (epithelial cells, fibroblasts, and myoblasts) is compared among three alginate-based microcapsules: (1) calcium-linked alginate microcapsules with a solubilized core and a poly-L-lysine-alginate-laminated surface; (2) barium-linked alginate beads with a gelled core; and (3) a hybrid formulation of barium-linked alginate beads with a poly-L-lysine-alginate-laminated surface. The mechanical stability of the different microcapsule types, as measured with a cone-and-plate shearing apparatus, was superior in the two barium-linked alginate beads. All cell types maintained high viability (65-90%) in culture after encapsulation. The recombinant gene products secreted by these cells (human growth hormone MW = 22,000, human factor IX MW = 57,000, and murine beta-glucuronidase MW = 300,000) were able to traverse the three microcapsule types at similar rates. Cell numbers within the microcapsules increased twofold to > 20-fold over 4 weeks, depending on the cell type. Epithelial and myoblast cell numbers were not affected by microcapsule formulation; however, fibroblasts proliferated the most in the calcium-linked alginate spheres. These results show that for culturing fibroblasts in a mechanically stable environment the classical calcium-linked microcapsules are adequate. However, where mechanical stability is a more critical requirement, the solid barium-linked gelled beads are more appropriate choices.
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PMID:Encapsulation of various recombinant mammalian cell types in different alginate microcapsules. 982 83

Implanting recombinant cells encapsulated in alginate microcapsules to express therapeutic proteins has been proven effective in treating several mouse models of human diseases (neurological disorders, dwarfism, hemophilia, lysosomal storage disease, and cancer). In anticipation of clinical application, we have reported the synthesis and characterization of a magnetized ferrofluid alginate that potentially allows tracking of these microcapsules in vivo by magnetic resonance imaging (MRI). We now report the properties of these ferrofluid microcapsules important for applications in gene therapy. When a mouse myoblast cell line was encapsulated in these microcapsules, it showed similar viability as in regular unmodified alginate capsules, both in vitro and in vivo, in mice. The permeability of these magnetized microcapsules, a critical parameter for immunoisolation devices, was comparable to that of classic alginate in the transit of various recombinant molecules of various molecular masses (human factor IX, 65 kDa; murine IgG, 150 kDa; and beta-glucuronidase, 300 kDa). When followed by MRI in vitro and in vivo, the ferrofluid microcapsules remained intact and visible for extended periods, allowing quantitative monitoring of microcapsules. At autopsy, the ferrofluid microcapsules were mostly free within the intraperitoneal cavities, with no overt inflammatory response. Serological analyses demonstrated a high level of biocompatibility comparable to that of unmodified alginate. In conclusion, ferrofluid-enhanced alginate microcapsules are comparable to classic alginate microcapsules in permeability and biocompatibility. Their visibility and stability to MRI monitoring permitted qualitative and quantitative tracking of the implanted microcapsules without invasive surgery. These properties are important advantages for the application of immunoisolation devices in human gene therapy.
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PMID:Encapsulation of recombinant cells with a novel magnetized alginate for magnetic resonance imaging. 1607 55

One method of nonviral-based gene therapy is to implant microencapsulated nonautologous cells genetically engineered to secrete the desired gene products. Encapsulating the cells within a biocompatible permselective hydrogel, such as alginate-poly-L-lysine-alginate (APA), protects the foreign cells from the host immune system while allowing diffusion of nutrients and the therapeutic gene products. An important consideration is which kind of cells is the best candidate for long-term implantation. Our previous work has shown that proliferation and differentiation of encapsulated C2C12 myoblasts in vitro are significantly improved by inclusion of basic fibroblast growth factor (bFGF), insulin growth factor II (IGF-II), and collagen within the microcapsules ("enhanced" capsules). However, the effects of such inclusions on the functional status of the microcapsules in vivo are unknown. Here we found that comparing the standard with the enhanced APA microcapsules; there was no difference in the rates of diffusion of recombinant products of different sizes, that is, human factor IX (FIX, 65 kDa), murine IgG (150 kDa), and a lysosomal enzyme, beta-glucuronidase (300 kDa), thus providing a key requirement of such an immunoprotective device. Furthermore, the creatine phosphokinase activity and myosin heavy chain staining (markers for differentiation of the myoblasts) and the cell number per capsule in the enhanced microcapsules indicated a higher degree of differentiation and proliferation when compared to the standard microcapsules, thus demonstrating an improved microenvironment for the encapsulated cells. Efficacy was tested in a melanoma cancer tumor model by treating tumor induced by B16-F0/neu tumor cells in mice with myoblasts secreting angiostatin from either the standard or enhanced APA microcapsules. Mice treated with enhanced APA-microcapsules had an 80% reduction in tumor volume at day 21 compared to a 70% reduction in those treated with standard APA-microcapsules. In conclusion, enhancement of APA microcapsules with growth factors and collagen did not adversely affect their permeability property and therapeutic efficacy. However, the enhanced differentiation and viability of the encapsulated myoblasts in vivo should be advantageous for long-term delivery with this method of gene therapy.
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PMID:Enhancement of myoblast microencapsulation for gene therapy. 1647 Aug 9