Diagnostic value of determinations of lysosomal hydrolases in CSF of patients with neurological diseases

Factors influencing the measurement of lysosomal enzymes activity in human cerebrospinal fluid

Measurements of the activities of lysosomal enzymes in cerebrospinal fluid have recently been proposed as putative biomarkers for Parkinson's disease and other synucleinopathies. To define the operating procedures useful for ensuring the reliability of these measurements, we analyzed several pre-analytical factors that may influence the activity of β-glucocerebrosidase, α-mannosidase, β-mannosidase, β-galactosidase, α-fucosidase, β-hexosaminidase, cathepsin D and cathepsin E in cerebrospinal fluid. Lysosomal enzyme activities were measured by well-established fluorimetric assays in a consecutive series of patients (n = 28) with different neurological conditions, including Parkinson's disease. The precision, pre-storage and storage conditions, and freeze/thaw cycles were evaluated. All of the assays showed within- and between-run variabilities below 10%. At −20°C, only cathepsin D was stable up to 40 weeks. At −80°C, the cathepsin D, cathepsin E, and β-mannosidase activities did not change significantly up to 40 weeks, while β-glucocerebrosidase activity was stable up to 32 weeks. The β-galactosidase and α-fucosidase activities significantly increased (+54.9±38.08% after 4 weeks and +88.94±36.19% after 16 weeks, respectively). Up to four freeze/thaw cycles did not significantly affect the activities of cathepsins D and E. The β-glucocerebrosidase activity showed a slight decrease (−14.6%) after two freeze/thaw cycles. The measurement of lysosomal enzyme activities in cerebrospinal fluid is reliable and reproducible if pre-analytical factors are accurately taken into consideration. Therefore, the analytical recommendations that ensue from this study may contribute to the establishment of actual values for the activities of cerebrospinal fluid lysosomal enzymes as putative biomarkers for Parkinson's disease and other neurodegenerative disorders.

A thermodynamic study of beta-N-acetylhexosaminidase enzyme heterogeneity in cerebrospinal fluid from patients with multiple sclerosis

BACKGROUND

ss-N-acetylhexosaminidase (Hex) is a lysosomal hydrolase, whose determination in the cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) has provided discordant results.

METHODS

Total Hex and its isoenzymes Hex A and Hex B were determined using a thermodynamic procedure in the CSF of 27 patients with definitive MS, 8 with possible MS, 9 with meningitis, 14 with other neurological diseases, and in 10 controls without any neurological disease.

RESULTS

In the group of patients with definitive MS, the total Hex and Hex A were significantly higher than in the control group (p<0.001), with a possible association of greater enzymatic activities with the presence of oligoclonal bands and recent relapse; however, an overlap was detected for the activities of total Hex and its isoenzymes between the groups of patients with different neurological diseases. A significant correlation was obtained for neuron-specific enolase (NSE) with total Hex and Hex A and Hex B isoenzymes (p<0.001); however, in the partial correlation statistical significance was only obtained between NSE and Hex A (p<0.001) which is the most abundant Hex isoenzyme in the brain.

CONCLUSIONS

Although the inflammatory process in MS mainly takes place in the perivascular zone, with little activity in the cerebral parenchyma, the significant increase of NSE and Hex A isoenzyme in CSF reveals a neuronal damage. The disease status may have effect on the CSF Hex activity.

Lysosomal hydrolases in cerebrospinal fluid of multiple sclerosis patients. A follow-up study

The change in activity of lysosomal hydrolases in the brain tissue of patients with demyelinating disease has been suggested to reflect the demyelination process. In this study we measured neutral proteinase (NP), acid proteinase (AP), and beta-glucuronidase (BG) activities in CSF of 32 patients with multiple sclerosis (MS) (remitting, remitting and relapsing, or chronic progressive course of the disease), 62 controls, and 4 patients with chronic inflammatory disease of central nervous system (ID). Samples from MS patients were taken at different clinical conditions of the disease during the 22-month follow-up. Elevated NP activity was found in patients with relapsing course of MS and also in patients with ID (P less than 0.05). NP activity correlated with the number of leucocytes in CSF of both MS (P less than 0.005, r = 0.50) and control (P less than 0.05, r = 0.21) patients. AP activity decreased in the MS group, especially in patients with remitting or remitting and relapsing courses of the disease (P less than 0.05), but even more in patients with ID (P less than 0.01). During the follow-up the increase in NP activity seemed to be associated with the clinical relapses of MS patients. Other enzymes did not fluctuate with the disease. This study suggests that the change in activity of lysosomal hydrolases is not specific for MS. The increase in NP activity in CSF is associated with clinical relapse of individual MS patients during the follow-up and may indicate immunological activation of the demyelination process in the brain. The large intra- and interindividual variation in enzyme activities in the CSF, however, makes the use of these enzymes difficult for diagnosis of MS and follow-up of MS activity.

Stability of enzymes of lysosomal origin in human cerebrospinal fluid

The optimal assay conditions and the stability of the following enzymes of lysosomal origin in human cerebrospinal fluid (CSF) were studied: acid phosphatase, beta-D-N-acetylglucosaminidase, alpha-D-galactosidase, beta-D-galactosidase, alpha-D-glucosidase, beta-D-glucosidase, alpha-L-fucosidase, alpha-D-mannosidase, beta-D-glucuronidase. The microsomal alpha-D-mannosidase, pH 5.7, was used as a reference non-lysosomal glycohydrolase. All the examined enzymes, with the only exception of beta-D-glucuronidase, underwent a more or less rapid loss of activity upon CSF storage in the temperature range from 37 degrees C to -80 degrees C. Storage in liquid nitrogen (-196 degrees C) was the only condition in which full activity for all tested enzymes was maintained for at least 15 days. Addition of human serum albumin to CSF, immediately after withdrawal, had a double effect in favouring enzyme stabilization and causing enzyme activation in some cases, and enzyme inhibition in others. Using conditions warranting enzyme stability the fluorimetric methods for lysosomal enzymes determination in cerebrospinal fluid appear to be highly reproducible (CV less than 5%) and simple enough for routine use.

Histochemical studies of lysosomal enzyme and nitroblue tetrazolium reduction of phagocytes in the cerebrospinal fluid of patients with infectious diseases of the central nervous system

Lysosomal enzyme levels and nitroblue tetrazolium (NBT) reduction of phagocytes in the cerebrospinal fluid (CSF) of patients with infectious diseases of the central nervous system (CNS) were studied histochemically to evaluate the function of phagocytes. Lysosomal enzymes of acid phosphatase and beta-galactosidase were demonstrated in mononuclear phagocytes and leptomeningeal cells, but not in polymorphonuclear leukocytes (PMN) and lymphocytes. In tuberculous meningitis, more than 60% of the cells were positive for the enzymes as compared with less than 30% for other diseases. Besides, the cells which stained highly for the enzymes were often found in the CSF of tuberculous meningitis. The lysosomal enzyme levels in the cells were dependent on the nature of the infection rather than on the intensity of inflammation when judged by total cell count in the CSF. On the other hand, reduced NBT formazan was found in PMN, mononuclear phagocytes, and leptomeningeal cells. The intensity of NBT reduction by these cells correlated well with the total cell count in CSF; i.e., enhanced NBT reduction by phagocytes reflected the intensity of the inflammation in the subarachnoid space. Thus, histochemical study of phagocytes in CSF can provide useful additional aids to the diagnosis of the nature and stage of CNS infection.

CSF lysosomal hydrolase activity as an aid in the diagnosis of bacterial meningitis

The activity of the lysosomal enzymes acid phosphatase, beta-glucuronidase, alpha-mannosidase and hexosaminidase were determined in CSF obtained from patients with proven bacterial meningitis and from patients with various other diagnoses. The mean value for CSF beta-glucuronidase from bacterial meningitis was elevated 73-fold when compared to the aggregate mean of all control groups. Acid phosphatase and alpha-mannosidase means were 26-fold and 33-fold elevated respectively while hexosaminidase was threefold elevated. Measurement of CSF acid phosphatase and beta-glucuronidase should prove a rapid useful test in establishing the diagnosis of bacterial meningitis. Chromatography of CSF samples on DEAE Sephadex allowed the resolution of hexosaminidase and beta-glucuronidase into individual isozymes. The ratio of hexosaminidase A to hexosaminidase B was generally higher in CSF from patients with bacterial meningitis but was very variable. The isozyme distribution for beta-glucuronidase was identical to that found in serum and no differences in pattern were found between patients and control subjects.

Intestinal lysosomal enzymes in the diagnosis of pancreatic disease

Acid hydrolases (lysosomal enzymes) were analyzed and compared with trypsin in duodenal juice obtained after a test meal (Lundh test). The possible diagnostic role of acid hydrolases in pancreatic disease was investigated. In all patients with chronic pancreatitis normal values of acid hydrolases but subnormal trypsin activities were found. In pancreatic cancer normal values of acid hydrolases and normal trypsin values were seen in three patients with small tumors, whereas five patients with more advanced cancer of the pancreas had decreased trypsin activity and three of them high activities of acid hydrolases in duodenal juice. In five patients operated on with a gastroenteroanastomosis acid hydrolases were markedly increased. Five patients had no activity of acid hydrolases in the aspirate, probably reflecting technical failure with dislodgement of the catheter from the duodenum to the stomach. In conclusion the assay of acid hydrolases does not seem to increase the diagnostic value of the conventional Lundh test (trypsin).

Lysosomal hydrolases in CSF of patients with multiple sclerosis

The activities of acid phosphatase and N-acetyl-beta-glucosaminidase have been measured in 171 samples of cerebrospinal fluid from 104 patients suffering from multiple sclerosis. The mean level of activity of these enzymes was lower than of controls. Patients who had the first or second bouts had somewhat higher activity of these enzymes compared to controls. The lowest values of these enzymes were found in patients with severe disability. Patients with late onset of the disease had higher levels of the enzymes compared to patients with an earlier debut of the illness, whereas patients with a short history had higher values than patients with a longer duration.