Quantifying Beta-Galactosylceramide Kinetics in Cerebrospinal Fluid of Healthy Subjects Using Deuterium Labeling.

Therapeutics promoting myelin synthesis may enhance recovery in demyelinating diseases, such as multiple sclerosis. However, no suitable method exists to quantify myelination. The turnover of galactosylceramide (myelin component) is indicative of myelination in mice, but its turnover has not been determined in humans. Here, six healthy subjects consumed 120 mL 70% D2 O daily for 70 days to label galactosylceramide. We then used mass spectrometry and compartmental modeling to quantify the turnover rate of galactosylceramide in cerebrospinal fluid. Maximum deuterium enrichment of body water ranged from 1.5-3.9%, whereas that of galactosylceramide was much lower: 0.05-0.14%. This suggests a slow turnover rate, which was confirmed by the model-estimated galactosylceramide turnover rate of 0.00168 day-1 , which corresponds to a half-life of 413 days. Additional studies in patients with multiple sclerosis are needed to investigate whether galactosylceramide turnover could be used as an outcome measure in clinical trials with remyelination therapies.

Small molecules present in the cerebrospinal fluid metabolome influence superoxide dismutase 1 aggregation.

Superoxide dismutase 1 (SOD1) aggregation is one of the pathological markers of amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disorder. The underlying molecular grounds of SOD1 pathologic aggregation remains obscure as mutations alone are not exclusively the cause for the formation of protein inclusions. Thus, other components in the cell environment likely play a key role in triggering SOD1 toxic aggregation in ALS. Recently, it was found that ALS patients present a specific altered metabolomic profile in the cerebrospinal fluid (CSF) where SOD1 is also present and potentially interacts with metabolites. Here we have investigated how some of these small molecules affect apoSOD1 structure and aggregation propensity. Our results show that as co-solvents, the tested small molecules do not affect apoSOD1 thermal stability but do influence its tertiary interactions and dynamics, as evidenced by combined biophysical analysis and proteolytic susceptibility. Moreover, these compounds influence apoSOD1 aggregation, decreasing nucleation time and promoting the formation of larger and less soluble aggregates, and in some cases polymeric assemblies apparently composed by spherical species resembling the soluble native protein. We conclude that some components of the ALS metabolome that shape the chemical environment in the CSF may influence apoSOD1 conformers and aggregation.

Repeated intrathecal injections of recombinant human 4-sulphatase remove dural storage in mature mucopolysaccharidosis VI cats primed with a short-course tolerisation regimen.

All MPS-VI cats treated thus far with weekly intravenous enzyme replacement therapy (IV ERT) with recombinant human N-acetylgalactosamine-4-sulphatase (rhASB) from 3 months of age onwards developed circulating anti-rhASB antibodies. In view of this, the possibility of inducing immune tolerance by using a short-course tolerisation regimen was tested. Starting at 4 months of age, MPS-VI (n=5) and unaffected cats (n=2) received cyclosporine and azathioprine over a 22-day period plus weekly IV ERT with 0.1mg/kg rhASB. After a 4-week resting period, these cats were administered weekly IV ERT with 1mg/kg rhASB until 11 or 17 months of age. Four unaffected cats (n=4) received weekly IV ERT only. Health, growth and seroconversion were regularly monitored. Four out of five MPS-VI cats tolerated rhASB well, as indicated by negligible or low antibody titres and absence of hypersensitivity reactions. One MPS-VI cat exhibited elevated antibody titres and hypersensitivity reactions during some IV treatments. The two unaffected cats that received the tolerisation regimen remained seronegative, however, only half of the unaffected cats not submitted to this regimen seroconverted. Only minor side-effects were attributed to the short-course of cyclosporine and azathioprine. Two MPS-VI cats also well-tolerated four weekly intrathecal injections of rhASB and consequently exhibited less oligosaccharide fragments in cerebrospinal fluid and less vacuolation within their dura mater. These data indicate that a relatively high rate of immunotolerance towards rhASB can be achieved in MPS-VI cats with a short-course tolerisation regimen ultimately permitting removal of lysosomal storage within the dura mater with the use of intrathecal therapy.

[A new method for the determination of sugars in cerebrospinal fluid (author's transl)]. / Neue Ergebnisse der Zuckeranalytik von Liquor cerebrospinalis.

The determination of fructose, galactose, glucose, mannose, rhamnose and ribose, using a newly developed liquid chromatography sugar analyzer is reported. High sensitivity (detection limit: 0.05 to 0.23 microgram per compound), resolution and specifity of the method permits the routine detection of carbohydrates in biological fluids without prior extraction and enrichment. The procedure opens new possibilities in medicinal diagnosis.

Separation of synthetic mixtures of sugars and of sugars in body fluids with a high-resolution carbohydrate analyzer.

With use of a specially designed gradient-generating system, of anion-exchange resins of 10-20 mum particle diameter, and of an orcinol solution in concentrated sulfuric acid (1 g/liter) as detection reagent, a mixture of 16 carbohydrates can be separated in less than 4 h. The limit of detection for most sugars is in the 0.1--2.0 nanomole range. The detection reagent is stable for months and does not become colored. The reagent mixes with the column effluent in an exothermic reaction and allows use of relatively short mixing coils. The analyzer is appropriate for investigating body fluids rapidly and with high sensitivity.