Activity of urine arylsulfatase A in brain­dead graft donors is a predictor of early and late graft function.

OBJECTIVE: Human lysosomal arylsulfatase A (ASA) is a member of the sulfatase family. Arylsulfatase A is required to degrade sulfatides. Sulfatides occur in the myelin sheets of the central and peripheral nervous system. In this study we evaluated the urine activity of lysosomal enzyme arylsulfatase A in brain­dead donors as a marker and predictor of short - and long­term renal allograft function. PATIENTS/METHODS: We analyzed data from kidney recipients who received organs from brain­dead donors. Data from 40 donors and 68 recipients were analyzed. RESULTS: Urine activity of arylsulfatase A in graft donors correlated positively with creatinine clearance in graft recipients after transplantation: significantly after 30 days (Rs=0.38, p=0.004) and after 3 years (Rs=0.38, p=0.03), and with borderline significance after 14 days (Rs=0.25, p=0.08) and after one year (Rs=0.23, p=0.07). CONCLUSIONS: The results of this study suggest that arylsulfatase A has a protective effect on kidney allograft, and the urine activity of this enzyme in kidney donors correlates positively with graft function.

Urinary lysosomal enzyme excretion in pregnant women with hypertensive disorders.

BACKGROUND: The authors assessed proximal renal tubular dysfunction and/or damage in pregnant women with various types of hypertension by measuring the three urinary lysosomal enzyme levels: N-acetyl-ß-d-glucosaminidase (NAG), arylsulfatase A and ß-glucuronidase. METHODS: The study consisted of 120 pregnant women divided into four groups: 41 women in 20th week of gestation or more, with pregnancy-induced hypertension (PIH group), 28 pregnant women after 20 weeks of pregnancy with pre-eclampsia (PE group), 21 pregnant women with chronic hypertension, identified before 20th week of pregnancy (CH group) and 30 healthy, pregnant women (healthy controls (HC) group). RESULTS: Statistical analysis showed significantly higher levels of all the three of lysosomal enzymes in the urine of patients with PE compared with the healthy pregnant women, pregnant women with PIH and the ones with chronic hypertension. Additionally, significantly higher values of NAG were found in the group of pregnant women with PIH compared with healthy pregnancies. No correlation was found between the concentration of enzymes in urine and values of blood pressure in any of the analyzed groups of pregnant women. CONCLUSIONS: The authors conclude that higher values of all the studied enzymes in PE group, in the comparison with the other groups, indicate proximal tubular damage at the cellular level. The lack of correlation between the concentration of lysosomal enzymes and blood pressure suggests that the damage to these parts of kidney is complex. In addition, mechanisms other than hypertension realizing intracellular enzymes may be involved in this process.

Expert recommendations for the laboratory diagnosis of MPS VI.

Mucopolysaccharidosis VI (MPS VI) is a lysosomal storage disease caused by a deficiency of N-acetylgalactosamine 4-sulfatase (arylsulfatase B, ASB). This enzyme is required for the degradation of dermatan sulfate. In its absence, dermatan sulfate accumulates in cells and is excreted in large quantities in urine. Specific therapeutic intervention is available; however, accurate and timely diagnosis is crucial for maximal benefit. To better understand the current practices for diagnosis and to establish diagnostic guidelines, an international MPS VI laboratory diagnostics scientific summit was held in February of 2011 in Miami, Florida. The various steps in the diagnosis of MPS VI were discussed including urinary glycosaminoglycan (uGAG) analysis, enzyme activity analysis, and molecular analysis. The following conclusions were reached. Dilute urine samples pose a significant problem for uGAG analysis and MPS VI patients can be missed by quantitative uGAG testing alone as dermatan sulfate may not always be excreted in large quantities. Enzyme activity analysis is universally acknowledged as a key component of diagnosis; however, several caveats must be considered and the appropriate use of reference enzymes is essential. Molecular analysis supports enzyme activity test results and is essential for carrier testing, subsequent genetic counseling, and prenatal testing. Overall the expert panel recommends caution in the use of uGAG screening alone to rule out or confirm the diagnosis of MPS VI and acknowledges enzyme activity analysis as a critical component of diagnosis. Measurement of another sulfatase enzyme to exclude multiple sulfatase deficiency was recommended prior to the initiation of therapy. When feasible, the use of molecular testing as part of the diagnosis is encouraged. A diagnostic algorithm for MPS VI is provided.

Coincidence of two novel arylsulfatase A alleles and mutation 459+1G>A within a family with metachromatic leukodystrophy: molecular basis of phenotypic heterogeneity.

In a family with three siblings, one developed classical late infantile metachromatic leukodystrophy (MLD), fatal at age 5 years, with deficient arylsulfatase A (ARSA) activity and increased galactosylsulfatide (GS) excretion. The two other siblings, apparently healthy at 12(1/2) and 15 years, respectively, and their father, apparently healthy as well, presented ARSA and GS values within the range of MLD patients. Mutation screening and sequence analysis disclosed the involvement of three different ARSA mutations being the molecular basis of intrafamilial phenotypic heterogeneity. The late infantile patient inherited from his mother the frequent 0-type mutation 459+1G>A, and from his father a novel, single basepair microdeletion of guanine at nucleotide 7 in exon 1 (7delG). The two clinically unaffected siblings carried the maternal mutation 459+1G>A and, on their paternal allele, a novel cytosine to thymidine transition at nucleotide 2435 in exon 8, resulting in substitution of alanine 464 by valine (A464V). The fathers genotype thus was 7delG/A464V. Mutation A464V was not found in 18 unrelated MLD patients and 50 controls. A464V, although clearly modifying ARSA and GS levels, apparently bears little significance for clinical manifestation of MLD, mimicking the frequent ARSA pseudodeficiency allele. Our results demonstrate that in certain genetic conditions MLD-like ARSA and GS values need not be paralleled by clinical disease, a finding with serious diagnostic and prognostic implications. Moreover, further ARSA alleles functionally similar to A464V might exist which, together with 0-type mutations, may cause pathological ARSA and GS levels, but not clinical outbreak of the disease.

[Changes in arylsulphatase activity (EC 3.6.1) in the blood serum and urine in women during the pregnancy and in the course of delivery]. / Zmiany aktywnosci arylosulfatazy A (EC 3.1.6.1) w surowicy i moczu kobiet w przebiegu ciazy i porodu fizjologicznego.

By the determination of arylsulphatase A activity (EC 3.1.6.1) in the blood serum and urine obtained from 66 women using the modified method by Lee-Vaupel and Conzelmann it was noticed the increase in the enzyme activity during the pregnancy comparing to the non-pregnant group. The highest enzyme activity was observed in the III trimester of pregnancy. In the following stages of delivery (I, II, III) it was assumed the increase in enzyme activity in urine. The highest enzyme activity in urine was observed in the stage III, and in the serum--in the stage II. It was compared the enzyme activity in primiparae and multiparae proving, that in the serum nd urine this activity is higher in the stages I and II in multiparae, and in the stage III in primiparae.

[The arylsulphatase A (EC 3.1.6.1) activity in serum, urine and amniotic fluid from pregnant women with EPH-gestosis]. / Aktywnosc arylosulfatazy A (EC 3.1.6.1) w surowicy, moczu i plynie owodniowym kobiet ciezarnych z EPH-gestoza.

In serum, urine and amniotic fluid obtained from the 52. women divided into three groups the arylsulphatase A (EC 3.1.6.1) activity was measured by the modified Lee-Vaupel and Conzelmann method. It was noticed in serum from the pregnant women with EPH-gestosis the statistically significant (p < 0.05) increase in the enzyme activity comparing to the results from non-pregnant women and pregnant with normal course of pregnancy. It was no statistically significant differences in the urine from pregnant with EPH-gestosis and from the healthy pregnant, but there was the increase (p < 0.01) in the enzyme activity in amniotic fluid from pregnant women with EPH-gestosis comparing to the physiological course of pregnancy. According to our data, the arylsulphatase A activity assay could be recommended as a diagnostic marker in the EPH-gestosis.

Practical suggestions in diagnosing metachromatic leukodystrophy in probands and in testing family members.

Metachromatic leukodystrophy (MLD) is one of the most severe genetically determined demyelination diseases. It is caused by a deficit in the activity of sulfatide sulfatase. The diagnosis is made by demonstrating a deficiency of arylsulfatase A (ASA) activity in leukocytes or cultured skin fibroblasts. Diagnosis based only on the activity of ASA is complicated by the fact that there exists a condition of ASA pseudodeficiency (Pd). Due to the relatively high risk of the MLD/Pd and MLDPd/Pd genotypes among families of patients, it is possible to make an erroneous diagnosis on the basis of only ASA activity. Nonetheless, it seems necessary to develop a reliable and simple diagnostic procedure so as to enable diagnosis and genetic counseling for carriers. We present two diagnostic flow charts entailing determination of ASA activity, identification of the pseudodeficit mutation and detection of sulfatides in a 24-hour urine collection.

Leucodistrofia metacromática / Metachromatic leukodystrophy

Introducción. La leucodistrofia metacromática (LMC) es una enfermedad hereditaria autosómica recesiva, caracterizada por una anormalidad en el metabolismo de la mielina, cuyos datos neurpatológicos más importantes son: la desmielinización en el sistema nervioso central (SNC) y periférico (SNP). Caso clínico. Pacientes con LMC iniciada después del año de edad con involucramiento progresivo de las funciones neurológicas de tipo motoras, trastornos del lenguaje, atrofia óptica, y signos extrapiramidales y cerebelosos. El diagnóstico se realizó tanto por imagen de tomografía axial computada y resonancia magnética nuclear de cráneo, así como en la disminución de la arilsulfatasa A en suero y aumento en la excreción de sulfátidos en orina. El estudio histopatológico confirmó la desmielinización de la sustancia blanca y el acúmulo de material metacromático en el SNC, SNP y otros órganos. Conclusión. La LMC debe sospecharse en la infancia temprana o tardía, cuando los pacientes tienen regresión del desarrollo psicomotor asociado a deterioro progresivo de las funciones cerebrales superiores, datos piramidales, extrapiramidales, cerebrales y neuropatía periférica

Actividad de la enzima aril sulfatasa A en pacientes con desórdenes esquizofrénicos / Aryl sulfatase a levels in patients with schizophrenic disorders

La leucodistrofia metacromática (LDM) es una enfermedad degenerativa causada por la deficiencia de la enzima aril sulfatasa A (ASA), que puede cursar con síntomas psiquiátricos. El propósito de esta investigación fue determinar la prevalencia de la deficiencia de ASA en un grupo de 23 pacientes con esquizofrenia. El valor de la mediana del ASA sérica en ellos fue 53.2 nmol/mL/h (rango 3.3-152-5). Seis (26 por ciento) presentaban actividades baja del ASA sérica (< 27.5 nmol/mL/h que es el límite inferior observado en 29 controles normales). Cinco de ellos tenían historia clínica de delirio de grandez, alucinaciones auditivas, hospitalizaciones múltiples, respuesta pobre a los neurolépticos y potenciales evocados anormales. Es probable que los síntomas esquizofrénicos fueran secundarios a la deficiencia de la enzima. Los hallazgos de este estudio son de utilidad en la clínica ya que ASA puede ayudar a identificar casos de LDM en pacientes presumiblemente esquizofrénicos

Metachromatic leukodystrophy in Greece: observations on 4 cases.

We report our findings in four cases of metachromatic leukodystrophy diagnosed in Greece during the last 4 years. The age of onset and the clinical symptoms were those described for the late infantile form of the disease. However, one patient retained his speech and mental abilities despite his pronounced motor regression and neurological involvement. This was combined with high residual arylsulphatase A activity in white blood cell homogenates even in the 0 degrees C incubation assay.

Arylsulfatase A in urine of patients with urothelial tumors.

A significant increase in urine arylsulfatase A activity (p less than 0.01) was found in patients with urothelial tumors. Arylsulfatase A activity was 1.36 +/- 1.10 U/24-h urine in control specimens, 1.90 +/- 1.66 U/24-h urine in various genitourinary tract disorders, and 3.90 +/- 1.98 U/24-h urine in transitional cell carcinoma specimens. Surgical treatment of the neoplastic patients lowered the arylsulfatase A activity found in urine to within reference values. The arylsulfatase A excreted by patients with these tumors was highly sensitive to thermal inactivation while the enzyme activity in the control urines was less affected by the heat treatment. The time course of the arylsulfatase A reaction with 4-nitrocatechol sulfate was not linear in normal individuals, while it was linear in 90% of patients with urothelial tumors. This difference in the kinetic pattern of the enzyme could be used to increase the diagnostic specificity of the determination.

Arylsulfatase A from human tissues contains an endo-beta-N-acetylglucosaminidase F-resistant oligosaccharide.

Homogeneous arylsulfatase A from human placenta, liver and urine contains two nonidentical subunits of 59 and 54 kDa. The two subunits are immunologically identical. The relative amount of low molecular weight subunits is only 20-30% of the total enzyme protein. Treatment of the enzyme under various conditions with endo-beta-N-acetylglucosaminidase F results in a decrease in the apparent molecular weight of both subunits by 1-2 kDa. a value that corresponds to the loss of a single N-linked oligosaccharide. However, as judged by carbohydrate staining, endo-beta-N-acetylglucosaminidase F does not remove all carbohydrate from the subunits or from glycopeptides of arylsulfatase A. In contrast, human prostatic acid phosphatase, a glycoprotein with a high content of mannose, hybrid and complex oligosaccharides is completely deglycosylated under identical experimental conditions. Several attempts to deglycosylate arylsulfatase A by chemical methods were unsuccessful due to poor recovery of the protein. From the present studies we conclude that arylsulfatase A contains an endo-beta-N-acetylglucosaminidase F resistant, perhaps O-linked carbohydrate.

The heterogeneity of arylsulphatase-A and arylsulphatase-B in normal human urine and urine from cancer patients.

Arylsulphatase-A and arylsulphatase-B heterogeneity in normal and cancer patient urine was investigated using high resolution agarose isoelectricfocusing. Normal urine contained up to nine forms of arylsulphatase-A activity with isoelectric points from 4.45 to 5.43 and at least 5 forms of arylsulphatase-B between 8.58 and 9.15 along with a broad zone of activity between pH 6.5 and 7.6. Although cancer patients had significantly higher levels of arylsulphatase-A and arylsulphatase-B activity, their pattern of activity was essentially the same as for the normals with only minor quantitative differences in some peaks.

Pancreatitis and alcoholism disorder the renal tubule and impair reclamation of some low molecular weight proteins.

We sought to determine whether the clinical setting in which pancreatitis occurs affects the incidence and distribution of increased values of renal clearance of amylase relative to creatinine, CAm/CCr, and whether the increased values reflect a tubular disorder that impairs renal reclamation of certain low molecular weight proteins. We measured the renal clearance of three low molecular weight proteins (amylase, beta 2-microglobulin, and lysozyme) and urinary excretion of three lysosomal enzymes that originate from the renal tubule in three groups of patients (alcoholic pancreatitis, pancreatitis without alcoholism, and alcoholism without pancreatitis). When compared to normal controls, the mean CAm/CCr was significantly elevated in alcoholic pancreatitis (p less than 0.05) but not in equally severe pancreatitis without alcoholism nor in alcoholism without pancreatitis. The clearance ratio of beta 2-microglobulin was significantly increased in each of the three patient groups; mean clearance ratio of lysozyme was not significantly increased in any of the patient groups. Excretion of each of the three lysosomal enzymes was significantly increased in each of the patient groups. We conclude that the etiology of pancreatitis affects the distribution of values for CAm/CCr, impaired tubular reclamation of amylase is the mechanism of the increase in CAm/CCr, and a factor or factors associated with both pancreatitis and with alcoholism per se appear to disorder the renal tubule and to impair tubular reclamation of some but not all low molecular weight proteins-a novel finding of considerable potential significance.

Catalytic and immunochemical properties of arylsulphatase A from urine, modified by potassium ferrate.

Arylsulphatase A (EC 3.1.6.1.) from urine was inactivated with potassium ferrate, a strong oxidizing agent. The inhibition could be prevented by competitive inhibitors, tetraborate and orthophosphate. Tetraborate which was shown to be a powerful competitive inhibitor (determined Ki = 4 X 10(-5) M) gave more efficient protection. The partially inactivated enzyme exhibited a Km value similar to that of the unmodified arylsulphatase A, and its Vmax decreased in proportion to the loss of enzymatic activity. The partially modified enzyme did not lose its ability to catalyse hydrolysis of p-nitrocatechol sulphate according to the "anomalous kinetics" exhibited towards this substrate and characteristic for arylsulphatase A. The immunochemical properties of arylsulphatase A either fully or partially inactivated were similar to those of the native enzyme. The results allow to conclude that ferrate reacts with arylsulphatase A in its active site. Thus ferrate seems to be a very sensitive probe for amino acid residues essential for catalytic activity of arylsulphatase A.

Phosphorylation and sulfation of arylsulfatase A accompanies biosynthesis of the enzyme in normal and carcinoma cell lines.

Arylsulfatase A (arylsulfate sulfohydrolase, EC 3.1.6.1), a mammalian lysosomal enzyme, is initially synthesized as a 69, 67 and 64 kDa precursor polypeptide in a prostate carcinoma cell line PC-3SF12, in HeLa cells and in a normal human embryonic lung cell line WI-38, respectively. These precursor polypeptides are secreted into the medium or processed to mature enzymes of apparent molecular mass 66, 64 or 62 kDa in PC-3SF12, HeLa or WI-38 cells, respectively. The precursor and mature polypeptides in WI-38 cells are phosphorylated, and the phosphate is lost upon treatment with endo-beta-hexosaminidase H. Arylsulfatase A is also shown to be sulfated in WI-38 cells. The presence of castanospermine, an inhibitor of sulfation of the second N-acetylglucosamine residue of the chitobiose core, does not reduce the extent of sulfation of arylsulfatase A, suggesting that either terminal sugars or the protein is sulfated. Sulfation may have a protective function similar to that of terminal sialic acid residues in glycoproteins. Although the subcellular location of arylsulfatase A is identical in PC-3SF12 and in WI-38 cells, pulse-chase experiments indicate that arylsulfatase A protein has a slower turnover in the prostate carcinoma cell line than it does in the normal human lung cell line. The differences in the apparent molecular weights of arylsulfatase A in the normal and carcinoma cell lines are shown to be due to variations in the carbohydrate content of the enzyme. The apparent molecular mass of the polypeptide chain obtained after endo-beta-hexosaminidase H treatment is 59 kDa, a value which is identical for all three cell lines studied here. These results suggest the possibility of an enhanced activity of terminal glucosyltransferase enzymes in carcinoma cell lines and in tumor tissues. Arylsulfatase A may be a useful marker for studying transformation-related processes in human cell lines.

Radioimmunoassay for arylsulfatase A in urine.

Purified arylsulfatase A (EC 3.1.6.1) from human urine was radioiodinated under conditions that caused no significant loss of antigenic activity. We used this labeled arylsulfatase A (specific radioactivity 4-7.5 Ci/g) together with nonlabeled enzyme and rabbit antiserum produced against homogeneous enzyme to develop a radioimmunoassay for arylsulfatase A in urine. A solid-phase, second-antibody technique (Immunobead Second Antibody; Bio-Rad Laboratories) was used to separate free enzyme from antigen-antibody complexes. The working range of the assay was 0.1-4.0 ng of enzyme; within- and between-assay CVs were around 10%, and the analytical recovery was 105.5% (SD 7.7%). The lower limit of detection was 0.08 ng of arysulfatase A per assay, substantially less than that of typical activity-based assays. Over a wide range of urinary arylsulfatase A activities, results by this method agreed well (r = 0.99) with those obtained by activity assays. We measured the enzyme in urines of 59 healthy volunteers and 92 patients with different diseases, including a group of colorectal cancer cases, to determine whether this could serve as a reliable marker for cancer of the colon; however, urinary excretion of arylsulfatase A by most patients with colon cancer was within normal limits.

Structural and immunochemical characterization of human urine arylsulfatase A purified by affinity chromatography.

Arylsulfatase A (aryl-sulfate sulfohydrolase, EC 3.1.6.1) was isolated from an ammonium sulfate precipitate of urinary proteins using two different affinity chromatography methods. One method involved the use of concanavalin A-Sepharose affinity chromatography at an early stage of purification, followed by preparative polyacrylamide gel electrophoresis. The other procedure employed arylsulfatase subunit affinity chromatography as the main step and resulted in a remarkably efficient purification. The enzyme had a specific activity of 63 U/mg. The final preparation of arylsulfatase A was homogeneous on the basis of polyacrylamide gel electrophoresis at pH 7.5, and by immunochemical analysis. However, when an enzyme sample obtained by either method of purification was subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis under reducing or non-reducing conditions, peptide subunits, of 63.5 and 54.5 kDa, were observed. Immunological tests with 125I-labeled enzyme established the presence of a common protein component in both of the electrophoretically separable peptide subunits of human urine arylsulfatase. The amino acid analysis of homogeneous human urine arylsulfatase A showed only a few differences between it and the human liver enzyme. However, immunological cross-reactivity studies using rabbit anti-human urine arylsulfatase revealed immunological difference between the human urine and liver arylsulfatase A enzymes.

Prevalence of partial cerebroside sulfate sulfatase (arylsulfatase A) defect in adult psychiatric patients.

Metachromatic leukodystrophy (MLD) is a disease caused by a deficiency of the enzyme sulfatide sulfatase, also known as arylsulfatase A (ASA). We compared the activity of this enzyme in adult psychiatric patients and normal volunteers using nitrocatechol sulfate (ASA-NCS) and cerebroside sulfate (ASA-CS) as substrates. Our results showed that ASA-NCS activity in urine and leukocytes was significantly lower in psychiatric than in normal individuals, but that there were no differences between these two groups in the sulfatide excretion in urine or the ASA-CS activity in leukocytes. There was no correlation between enzyme activity in urine and in leukocytes, indicating that activity in urine does not truly reflect the levels of the enzyme in tissues. The correlation between ASA-NCS and ASA-CS activity in leukocytes was poor (0.51 for psychiatric patients and 0.59 for normals), suggesting that for a valid measure of the enzyme activity the assays should be carried out with CS as substrate. Results of our study also indicate that in 39 of the 145 psychiatric patients studied, the ASA-CS activity in leukocyte was less than 4 nmoles/mg protein/hr, which is below 50% of the normal means, whereas only one of the 30 normal subjects had a value this low. The presence of low levels of ASA-CS activity in a significantly large number of adult patients with varying psychiatric manifestations suggests that such patients may be asymptomatic carriers of the sulfatidase defect (heterozygotes for MLD), and that behavioral and functional disturbances in these patients may at least in part be related to sulfatidase deficiency. The significance of the ASA-NCS abnormality (reduction) in psychiatric patients is unclear.