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Rat heart perfusion as model system for enzyme replacement therapy in glycogenosis type II.

Cardiac failure and skeletal muscle weakness are the main clinical features of glycogenosis type II, a lysosomal storage disorder caused by acid alpha-glucosidase deficiency. In our study, we have investigated in a rat heart perfusion-recirculation system whether acid alpha-glucosidase can be taken up from the vascular system into cardiomyocytes. When rat hearts were perfused with mannose 6-phosphate-containing acid alpha-glucosidase purified from bovine testis, a 3- to 4-fold increase of enzyme activity was obtained. Perfusion with human placental acid alpha-glucosidase not containing the mannose 6-phosphate recognition marker did not have such an effect. The presence of bovine testis acid alpha-glucosidase in heart tissue was demonstrated by immunoblotting. Immunocytochemistry provides evidence for uptake of the exogenous enzyme in lysosomes of the cardiomyocytes. The relevance of these findings for enzyme therapy in glycogenosis type II is discussed.

Animals↗

Serum chitotriosidase activity in Gaucher patients on enzyme replacement therapy (ERT).

OBJECTIVE: Changes of serum chitotriosidase activity during Ceredase treatment of Gaucher patients. DESIGN AND METHODS: Ten Gaucher patients were treated with Ceredase for up to 30 months. Serum or plasma chitotriosidase activity was measured using 4-methylumbelliferyl-beta-D-N,N',N"triacetyl-chitotrioside. RESULTS: In untreated patients, serum chitotriosidase activity did not depend on the patient's age and was not a measure of clinical status, type or progress of the disease. Chitotriosidase activity declined during treatment with Ceredase, but still remained high. The largest decline in enzyme activity was observed in patients with type III of the disease who had intact spleens; splenectomized type III patients, and type I patients reacted more slowly. CONCLUSIONS: Serum chitotriosidase activity may indicate that a patient has reacted to treatment, however, it can not be considered a direct marker of treatment effectiveness.

Adolescent↗

Enzyme replacement therapy in ENU2 phenylketonuric mice using oral microencapsulated phenylalanine ammonia-lyase: a preliminary report.

The presence of an extensive enterorecirculation of amino acids between the intestine and the body allows the removal of systemic phenylalanine in PKU rats by oral microencapsulated phenylalanine ammonia lyase. The work presented in this article has the main goal of assessing the feasibility of yeast phenylalanine ammonia-lyase (PAL) loaded collodion microcapsules in reducing elevated plasma phenylalanine concentrations to standard levels in genetically mutated PKU mice, within a 30 day time frame. The distinguishing aspect from previous studies lies in the available animal model. Rather than artificial induction of elevated phenylalanine plasma levels, the mice representing the human phenylketonuric condition, are mutated strains which are deficient in the enzyme phenylalanine hydroxylase. The first in vivo study established a method for orally feeding microcapsules, both control and enzyme loaded, over 30 consecutive days, by mixing with soft, unripened cheese. Under this unique regime a decrease of 51.3% +/- 9.02% in phenylalanine plasma levels was observed after 23 days. Reduction in the phenylalanine plasma levels to within the desired maintenance range of 250-1000 umol/L was observed in 2 out of 4 PAL treated mice, with only 50% of the PAL dose used in previous rat studies by Chang's group. The second animal study confirmed the finding in the first in vivo study that there is no significant decrease in the plasma phenylalanine levels within the first seven days. This may be due to the severely deteriorated physical condition of the ENU mice used, the PAL enzyme preparations available or the fact that normal mice contain 10 times the amount of phenylalanine hydroxylase as compared with humans, thus requiring larger doses of PAL in order to be effective in a shorter time span.

Administration, Oral↗

Advances in the management of Anderson-Fabry disease: enzyme replacement therapy.

Anderson-Fabry disease (AFD) is a lysosomal storage disorder (LSD) due to alpha-galactosidase A (alpha-Gal A) deficiency and the resultant accumulation of incompletely metabolised glycosphingolipids (GSLs), primarily globotriosylceramide (Gb(3)), within various tissues. It is an X-linked multisystem disorder characterised by progressive renal insufficiency, with added morbidity from cardio- and cerebrovascular involvement, and associated with significant impact on quality of life and diminished lifespan. The disease manifests primarily in hemizygous males; however, there is increasing recognition that heterozygous (carrier) females may also develop disease-related complications, although onset among affected women may be delayed. Until recently, treatment has been limited to symptomatic management of pain and other measures to alleviate the problems associated with end-stage complications from renal, cardiac and nervous system involvement. The availability of the recombinant enzyme offers the potential of a safe and effective targeted treatment approach. At the moment, two distinct enzyme formulations are approved in Europe (and in other countries) and both continue to undergo FDA evaluation in the US. Increasing knowledge of the natural history of AFD and greater experience with enzyme therapy should enable optimal patient care. The relative rarity and complexity of AFD necessitates a multi-disciplinary team approach that may be facilitated by a centralised registry.

Animals↗

[Anderson-Fabry's disease: diagnostic problems, therapeutic relevance, and clinical experience in the treatment of the disease with enzyme replacement therapy in nephropathic patients].

Aim of this study was to confirm the initial results of a clinical trial on the treatment of Fabry's disease carried out in 13 Italian Nephrology Units. Fabry's disease is a rare, X-linked inherited disease, characterized by a-galactosidase (a-GAL) deficiency, a lysosomial enzymatic activity that results in the accumulation of neutral glycosphingolipids in the endothelial cells of the whole body, and causes painful crises, acroparesthesiae, angiokeratomas, corneal and lens dystrophy, and progressive damage to kidneys, heart and central nervous system, as well as potentially leading to death. The present availability of the recombinant form of a-GAL allows us to prevent or stop the long-term complications of this disease. A clinical trial, generously supported by Genzyme, was started on February 2001. In this trial 20 patients affected by Fabry's disease were periodically treated with agalsidase-beta, the commercial form of the enzyme. The initial results of the trial have indicated that the drug is capable of reducing both the number and intensity of painful crises, improving the patient's sensation of well-being, thus suggesting that this therapeutic approach might theoretically increase life expectancy in these patients.

Chromosomes, Human, X↗

Impaired microbicidal capacity of mononuclear phagocytes from patients with type I Gaucher disease: partial correction by enzyme replacement therapy.

The higher susceptibility to serious bacterial infections in patients with Gaucher disease (GD) may be due in part to defective function of phagocytic cells. We studied five patients with GD (type I) and examined the ability of granulocytes and mononuclear phagocytes from these patients to phagocytose and kill Staphylococcus aureus and to generate superoxide anion (O2-) on stimulation with fully opsonized bacteria. Serum-opsonized staphylococci were ingested equally by phagocytic cells from patients and controls. In the presence of normal serum, the extent of killing of S aureus and the release of O2- by granulocytes over incubation periods of 60 minutes and 30 minutes, respectively, were also equivalent for patients and controls. However, we found that killing of viable bacteria and release of O2- by the patients' monocytes was significantly lower than that in cells from controls (P < .05 for both). The magnitude of differences in killing and O2- release between patients' cells and those from controls was even more profound with monocyte-derived macrophages. Enzyme augmentation with macrophage-targeted glucocerebrosidase preparation for 6 months at doses from 7.5 to 10 U/kg/wk resulted in significant increases of functional activities and O2- generation of monocytes and macrophages along with hematologic and hepatosplenic improvements. These data suggest that mononuclear phagocytes from GD patients are defective in their ability to kill bacteria and to generate reactive oxygen intermediates. Our data also suggest that enzyme substitution may improve functions of monocytes and macrophages in patients with GD that should make them more resistant to severe bacterial infection.

Gaucher Disease↗

Enzyme replacement therapy in severe Fabry disease with renal failure: a 1-year follow-up.

We present here the course of clinical response of a 53-year-old haemodialysed Fabry patient who received recombinant human alpha-galactosidase A at a dose of 1 mg/kg every other week over a period of 1 year. The therapy was well tolerated by the patient, who revealed an impressive favourable cutaneous, gastrointestinal, neurological and psychiatric response and a dramatic improvement in his quality of life, but no improvement in cardiac and renal function.

Enzyme Therapy↗

Enzyme replacement therapy for mucopolysaccharidosis I: a randomized, double-blinded, placebo-controlled, multinational study of recombinant human alpha-L-iduronidase (laronidase).

OBJECTIVE: To confirm the efficacy and safety of recombinant human alpha-L-iduronidase (laronidase) in patients with mucopolysaccharidosis I (MPS I). STUDY DESIGN: This was a randomized, double-blinded, multinational study of 45 patients with MPS I administered 100 U/kg (0.58 mg/kg) laronidase, or placebo intravenously weekly for 26 weeks. The coprimary efficacy end points compared the median change from baseline to week 26 between groups in percentage of predicted normal forced vital capacity (FVC) and in 6-minute walk test (6MWT) distance through the use of the Wilcoxon rank sum test. RESULTS: The laronidase (n=22) and placebo (n=23) groups had similar baseline characteristics. After 26 weeks, patients receiving laronidase compared with placebo showed mean improvements of 5.6 percentage points in percent of predicted normal FVC (median, 3.0; P=.009) and 38.1 meters in 6MWT distance (median, 38.5; P=.066; P=.039, analysis of covariance). Laronidase also significantly reduced hepatomegaly and urinary glycosaminoglycans, and, in more severely affected patients, improved sleep apnea/hypopnea and shoulder flexion. Laronidase was well-tolerated. Nearly all patients receiving enzyme had development of IgG antibodies, without apparent clinical effects. CONCLUSIONS: In patients with MPS I, laronidase significantly improves respiratory function and physical capacity, reduces glycosaminoglycan storage, and has a favorable safety profile.

Adolescent↗

Pancreatic enzyme replacement therapy.

Malabsorption due to severe pancreatic exocrine insufficiency is one of the most important late features of chronic pancreatitis. Generally, steatorrhea is more severe and occurs several years prior to malabsorption of other nutrients because synthesis and secretion of lipase are impaired more rapidly, its intraluminal survival is shorter, and the lack of pancreatic lipase activity is not compensated for by nonpancreatic mechanisms. Patients suffer not only from nutritional deficiencies but also from increased nutrient delivery to distal intestinal sites, causing symptoms by profound alteration of upper gastrointestinal secretory and motor functions. Adequate nutrient absorption requires delivery of sufficient enzymatic activity into the duodenal lumen simultaneously with meal nutrients. The following recommendations are based on modern therapeutic concepts: 25,000 to 40,000 units of lipase per meal using pH-sensitive pancreatin microspheres, with dosage increases, compliance checks, and differential diagnosis in case of treatment failure. Still, in most patients, lipid digestion cannot be completely normalized by current standard therapy, and future developments are needed to optimize treatment.

Digestion↗

Low-dose enzyme replacement therapy for Gaucher's disease: effects of age, sex, genotype, and clinical features on response to treatment.

Although alglucerase therapy has become the treatment of choice for symptomatic patients with Gaucher's disease, the low-dose/high-frequency regimen introduced as a means to reduce the high cost of treatment has raised major controversy. We evaluated the efficacy and safety of low-dose alglucerase in 29 patients with Gaucher's disease who completed 6 to 28 months of therapy. All received intravenous alglucerase at a monthly dose of 30 units/kg, given usually in equal doses 3 times a week. All patients responded well to treatment. The hematological improvement and the reduction in organomegaly were satisfactory. No correlation was found between age, sex, genotype, previous splenectomy, or severity score index and the response to treatment. Patients with a greater degree of hepatomegaly tended to have a more pronounced decrease in liver size, although this reduction did not reach statistical significance. We confirmed that a low-dose/high-frequency regimen of alglucerase was as effective as a high-dose/low-frequency protocol in the treatment of Gaucher's disease, even in the severely ill. Whenever cost is an issue, we recommend using this low-dose regimen.

Adolescent↗