Effect of u18666a on beta-glucosidase, sphingomyelinase, and beta-galactosidase activities in astrocytes of young rats.

Niemann-Pick type C disease (NPC) is a neurodegenerative genetic disorder caused by accumulation of lipids, especially cholesterol, in the perinuclear space. U18666A is a cholesterol transport-inhibiting agent, being used to mimic NPC, mainly in fibroblasts. The objective of this study was to observe the effect of the drug U18666A, which causes the accumulation of cholesterol in the cytoplasm of astrocytes from newborn rats, on some lysosomal hydrolase activities. Filipin staining and fluorescence microscopy, through CellM software, were used for visualization and quantification of cholesterol. The dose of U18666A that provided the greatest accumulation of cholesterol was that of 0.25 µg/mL in incubation for 48 h. Primary rat astrocytes incubated with the drug (NPC) showed a significantly higher amount of cholesterol than those without U18666A (controls). The measurement of activity of enzymes sphingomyelinase and beta-glucosidase in astrocytes of rats with NPC was significantly lower than that of control astrocytes, which is consistent with the disease in humans. The activity of the enzyme beta-galactosidase showed no significant difference between both groups. We concluded that U18666A appears to be an excellent intracellular cholesterol transport-inhibiting agent affecting some metabolic pathways in astrocytes of young rats, which mimics NPC in these animals. Just like the change in the activity of lysosomal enzymes has been demonstrated, other biochemical parameters of the cell can be tested with this animal model, thus contributing to a better understanding of the disease.

Oxidative stress parameters of Gaucher disease type I patients.

Enzymatic deficiency in Gaucher disease (GD) patients may induce a cascade of events, culminating in secondary effects such as the production of reactive oxygen species (ROS). Detoxification through biological systems which remove or repair the damage may cause the production of peroxides and free radicals that damage all cell components, including proteins, lipids and ADN. The study's aim was the test, using the analysis of plasma samples' the use of lipid peroxidation by thiobarbituric acid reactive substances (TBARS), protein damage by carbonyl assay, non-enzymatic antioxidant defenses by sulfhydryl (SH) content, antioxidant enzymatic defenses by catalase (CAT) and superoxide dismutase (SOD), from patients with GD type I patients who received no prior treatment. Blood samples were collected from 10 patients previously diagnosed with GD type I and from 11 healthy subjects. Chitotriosidase (CT) activity was measured in plasma and the activity of ß-glucosidase (GBA) was measured in leukocytes. The results showed a significant increased (p < 0.005) in GD samples when compared to healthy controls in CAT, SOD and SH, but there was no change in TBARS and carbonyl in the comparison between the two groups. In conclusion, the present data indicates the increased levels of enzymatic and non-enzymatic defenses without any effect on lipid peroxidation and damage to proteins. We believe that the results of this study are relevant to understanding the cellular changes involved in this important LSDs.