LRRK2 exonic variants are associated with lysosomal hydrolase activities and lysosphingolipid alterations in Parkinson's disease

Last data demonstrated that exonic variants of LRRK2 (p.G2019S, p.M1646T) may affect the catalytic activity of lysosomal enzyme glucocerebrosidase (GCase) probably through the phosphorylation of Rab10 protein. We aimed to evaluate an association of LRRK2 exonic variants previously associated with alteration of phosphorylation levels for Rab10Thr73 with PD risk in Russian population and analyze an impact of p.G2019S mutation and selected LRRK2 variants on lysosomal hydrolase activities. LRRK2 variants were determined by full sequencing of LRRK2 in 508 PD patients and 470 controls from Russian population. Activity of lysosomal enzymes (glucocerebrosidase (GCase), alpha-galactosidase A (GLA), acid sphingomyelinase (ASMase) and concentrations of their corresponded substrates (hexosylsphingosine (HexSph), globotriaosylsphingosine (LysoGb3), lysosphingomyelin (LysoSM), respectively) were estimated in 211 PD patients and 179 controls by liquid chromatography with tandem mass spectrometry (LC-MS-MS) in dry blood spots. p.M1646T and p.N2081D were associated with PD (OR = 2.33, CI 95%: 1.1215 to 4.8253, p = 0.023; OR = 1.89, 95%CI: 1.0727 to 3.3313, p = 0.028, respectively) in Russian population. An increased LysoGb3 concentration was found in p.G2019S and p.N2081D LRRK2 carriers among PD patients compared to both PD patients and controls (p.G2019S: p = 0.00086, p = 0.0004, respectively; p.N2081D: p = 0.012, p = 0.0076, respectively). A decreased ASMase activity in p.G2019S LRRK2 carriers among PD patients (p = 0.014) was demonstrated as well. Our study supported possible involvement of LRRK2 dysfunction in an alteration of sphingolipid metabolism in PD.

Effect of Lysosomes on Extending Vase Life of Cut Flowers

In this study, we were investigated the effect of lysosomal extracts (named as lysosomal enzymes) on extending the vase life of cut flowers. The results confirmed that senescence of cut freesia treated with lysosomal enzymes delayed. Also, the results for cut roses and lilies showed a similar pattern. In the case of them the fresh weight was lower than that of the control group, but time the ornamental value was retained increased by about 2 days. The reasons have explained as results by the change including stomata, accumulation of microbial population, and soluble carbohydrate contents. In conclusion, pretreatment with lysosomal enzymes has enhanced vase life and ornamental value of cut flowers. It has an important significance in improving the marketability of cut flowers in the flower industry. Therefore, lysosomal enzymes have the potential to be used sufficiently as eco-friendly and effective materials for pretreatment agents in the cut flower industry.

Cardio-protective effects of Terminalia catappa leaves and Terminalia chebula fruit extract in doxorubicin-induced cardiomyopathy in rats

INTRODUCTION

The cardio-protective effects of Terminalia catappa and Terminalia chebula are well-recognized in Ayurveda for its antimicrobial, antidiabetic and antioxidant potentials. The present study evaluates the effects of T. catappa leaves (Tct.LE) and T. chebula fruits (Tce.FE) against doxorubicin (DOX)-induced rats through analysis of the cardiac biomarkers, tricarboxylic acid (TCA) cycle enzymes and respiratory chain enzymes for their cardio-protective properties. Materials and methods: This study includes 42 adult male Albino Wistar rats randomized into seven groups for 21-days. Groups were categorized as control; DOX (1.5 mg/kg) induced negative control; basal diet with 300 mg/kg of Tct.LE, with 300 mg/kg Tce.FE; DOX with 300 mg/kg of Tct.LE, Tce.FE, and propranolol (25mg/kg). Results and Discussion: The doses of 300 mg/kg of both plants have a significant effect on the TCA cycle, respiratory and lysosomal enzymes activity. The troponin levels are significantly reduced in plant treated group than the DOX-treated rats when compared with the control and propranolol treated group. Likewise, the increased level of creatine kinase-muscle/MB, creatine kinase and lipid profile in the DOX-treated animals were significantly reduced upon being treated with extracts. Conclusion: The cardio-protective activity of Tct.LE leaves and Tce.FE indicate its potential use in the management of cardiovascular diseases.

CLINICAL SIGNIFICANCE

The prevalence of cardiovascular disease is increasing day-by-day in this industrial world with leading cause of mortality and morbidity. Many researches are presently concentrated on the plant-based medicine due to its safety and free from side effects. Hence, the present study aims to document the potential cardio-protective benefits of Terminalia catappa and Terminalia chebula.

Measurement of lysosomal enzyme activities: A technical standard of the American College of Medical Genetics and Genomics (ACMG)

Assays that measure lysosomal enzyme activity are important tools for the screening and diagnosis of lysosomal storage disorders (LSDs). They are often ordered in combination with urine oligosaccharide and glycosaminoglycan analysis, additional biomarker assays, and/or DNA sequencing when an LSD is suspected. Enzyme testing in whole blood/leukocytes, serum/plasma, cultured fibroblasts, or dried blood spots demonstrating deficient enzyme activity remains a key component of LSD diagnosis and is often prompted by characteristic clinical findings, abnormal newborn screening, abnormal biochemical findings (eg, elevated glycosaminoglycans), or molecular results indicating pathogenic variants or variants of uncertain significance in a gene associated with an LSD. This document, which focuses on clinical enzyme testing for LSDs, provides a resource for laboratories to develop and implement clinical testing, to describe variables that can influence test performance and interpretation of results, and to delineate situations for which follow-up molecular testing is warranted.

Imbalanced cellular metabolism compromises cartilage homeostasis and joint function in a mouse model of mucolipidosis type III gamma

Mucolipidosis type III (MLIII) gamma is a rare inherited lysosomal storage disorder caused by mutations in GNPTG encoding the γ-subunit of GlcNAc-1-phosphotransferase, the key enzyme ensuring proper intracellular location of multiple lysosomal enzymes. Patients with MLIII gamma typically present with osteoarthritis and joint stiffness, suggesting cartilage involvement. Using Gnptg knockout (Gnptgko ) mice as a model of the human disease, we showed that missorting of a number of lysosomal enzymes is associated with intracellular accumulation of chondroitin sulfate in Gnptgko chondrocytes and their impaired differentiation, as well as with altered microstructure of the cartilage extracellular matrix (ECM). We also demonstrated distinct functional and structural properties of the Achilles tendons isolated from Gnptgko and Gnptab knock-in (Gnptabki ) mice, the latter displaying a more severe phenotype resembling mucolipidosis type II (MLII) in humans. Together with comparative analyses of joint mobility in MLII and MLIII patients, these findings provide a basis for better understanding of the molecular reasons leading to joint pathology in these patients. Our data suggest that lack of GlcNAc-1-phosphotransferase activity due to defects in the γ-subunit causes structural changes within the ECM of connective and mechanosensitive tissues, such as cartilage and tendon, and eventually results in functional joint abnormalities typically observed in MLIII gamma patients. This idea was supported by a deficit of the limb motor function in Gnptgko mice challenged on a rotarod under fatigue-associated conditions, suggesting that the impaired motor performance of Gnptgko mice was caused by fatigue and/or pain at the joint.This article has an associated First Person interview with the first author of the paper.

LC/MS Methods for Studying Lysosomal ADC Catabolism

A critical component of antibody-drug conjugate (ADC) development is identification or verification of the active released entity upon cellular uptake and exposure to lysosomal enzymes. Coupled with LC/MS, commercial human lysosomal preparations can be used as an in vitro tool to explore the release characteristics of new ADCs, and gain information on potential metabolic or chemical liabilities of new payload structures. A general method for approaching this is described for cathepsin B-cleavable as well as non-cleavable ADCs, and opportunities for tailoring the method to specific cases are indicated.

Activity of Lysosomal Enzymes During Protein Malnutrition and Progesterone Supplementation in the Mouse

This study investigated the effects of protein malnutrition and progesterone supplementation on the activities of a spectrum of lysosomal enzymes in tissue fragments of mouse liver and kidney. The working hypothesis was that the known anti-stress action of progesterone could have to do with the inhibition of lysosomes which are engaged in apoptotic and oxidative stress-induced responses. The study investigated the effects of exogenous progesterone in chronically (3 weeks) protein-malnourished (10% protein) mice on the activities of lysosomal hydrolases in liver and kidney tissues. Progesterone was injected intraperitoneally in a dose of 2 μg/g body mass dissolved in a vehicle volume of 10 μL/g body mass during the final 3 days of exposure to either low 10% or standard 16% protein content in the chow. After euthanizing the animals, tissue fragments of liver and kidney assayed for the content of lysosomal enzymes. The results demonstrated the stimulating effect of protein malnutrition on lysosomal activities. We further found, contrary to our hypothesis, that progesterone supplementation during both standard and low-protein conditions enhanced lysosomal activities, particularly acting in concert with protein malnutrition in kidney tissue. The effects were selective concerning both lysosomal enzymes and tissues and of highly variable magnitude. Nonetheless, we believe we have shown that progesterone assists protein malnutrition in stimulation of lysosomal enzymes, which suggests the possibility of the hormone's engagement in cleansing the cellular milieu in disorders consisting of accumulation of toxic molecules.

Biochemical and morphological changes in mouse liver induced by mistletoe toxins

Natural compounds are often characterized by high biological activity and sometimes toxicity. This also applies to compounds contained in the herb mistletoe. The objective of this study was to investigate short-term effects (up to 48 h) of mistletoe toxins on mouse hepatocytes. Standardized mistletoe extract Iscador P was given to female mice as a single injection (0.1 mg/kg b.w., 1 mg/kg b.w., or 2 mg/kg b.w). Activities of lysosomal hydrolases: acid phosphatase, cathepsins D and L, N-acetyl-β-D-hexosaminidase, β-D-glucuronidase, β-D-glucosidase and cytosolic proteases: arginine and leucine aminopeptidases were analyzed in the liver fractions 24 and 48 h after the injection. The morphology of hepatocytes was examined by light and transmission electron microscopy. Iscador P caused a decrease in the activity of all lysosomal hydrolases (except cathepsins) in the lysosomal pellet, and an increase in the activity of both aminopeptidases and β-D-glucuronidase in the cytosol. However, despite membranotropic properties of the viscotoxins, we did not find a significant labilising effect on the lysosomal membranes. Only β-D-glucuronidase activity was relocated to the supernatant of lysosomal fraction. Microscopic examinations revealed that hepatocyte mitochondria were enlarged and increased in number, whereas the surface of the rough endoplasmic reticulum was decreased significantly.

Hypoxia-ischemia alters distribution of lysosomal proteins in rat cortex and hippocampus

Neuronal excitotoxicity induced by glutamatergic receptor overstimulation contributes to brain damage. Recent studies have shown that lysosomal membrane permeabilization (LMP) is involved in ischemia-associated neuronal death. In this study we evaluated the effect of neonatal hypoxia-ischemia (HI), as a model of excitotoxicity, on the lysosomal integrity throughout the distribution of the lysosomal proteins cathepsin D and prosaposin. Rat pups (7 days old) of the Wistar Kyoto strain were submitted to HI and they were euthanized 4 days after treatment and the cerebral cortex (Cx) and hippocampus (HIP) were processed for immunohistochemistry or immunoblotting. Treatment induced an increase of gliosis and also a redistribution of both prosaposin and cathepsin D (as intermediate and mature forms), into the cytosol of the HIP and Cx. In addition, HI induced a decrease of LAMP-1 in the membranous fraction and the appearance of a reactive band to anti-LAMP-1 in the cytosolic fraction, suggesting a cleavage of this protein. From these results, we propose that the abnormal release of Cat D and PSAP to the cytosol is triggered as a result of LAMP-1 cleavage in HI animals, which leads to cell damage. This could be a common mechanism in pathological conditions that compromises neuronal survival and brain function.

Summary: Hypoxia ischemia (HI) induces an increase of gliosis and redistribution of prosaposin and cathepsin D into the cytosol of rat hippocampus. This could be triggered by LAMP-1 cleavage in HI.

Biochemical Characterization of a Lysosomal α-Mannosidase from the Starfish Asterias rubens

Acidic α-mannosidase is an important enzyme and is reported from many different plants and animals. Lysosomal α-mannosidase helps in the catabolism of glycoproteins in the lysosomes thereby playing a major role in cellular homeostasis. In the present study lysosomal α-mannosidase from the gonads of echinoderm Asterias rubens was isolated and purified. The crude protein sample from ammonium sulfate precipitate contained two isoforms of mannosidase as tested by the MAN2B1 antibody, which were separated by anion exchange chromatography. Enzyme with 75 kDa molecular weight was purified and biochemically characterized. Optimum pH of the enzyme was found to be in the range of 4.5-5 and optimum temperature was 37 °C. The activity of the enzyme was inhibited completely by swainsonine but not by 1-deoxymannojirimycin. Ligand blot assays showed that the enzyme can interact with both the lysosomal enzyme sorting receptors indicating the presence of mannose 6-phosphate in the glycan surface of the enzyme. This is the first report of lysosomal α-mannosidase in an active monomeric form. Its interaction with the receptors suggest that the lysosomal enzyme targeting in echinoderms might follow a mannose 6-phosphate mediated pathway similar to that in the vertebrates.

Induced pluripotent stem cell models of lysosomal storage disorders

Induced pluripotent stem cells (iPSCs) have provided new opportunities to explore the cell biology and pathophysiology of human diseases, and the lysosomal storage disorder research community has been quick to adopt this technology. Patient-derived iPSC models have been generated for a number of lysosomal storage disorders, including Gaucher disease, Pompe disease, Fabry disease, metachromatic leukodystrophy, the neuronal ceroid lipofuscinoses, Niemann-Pick types A and C1, and several of the mucopolysaccharidoses. Here, we review the strategies employed for reprogramming and differentiation, as well as insights into disease etiology gleaned from the currently available models. Examples are provided to illustrate how iPSC-derived models can be employed to develop new therapeutic strategies for these disorders. We also discuss how models of these rare diseases could contribute to an enhanced understanding of more common neurodegenerative disorders such as Parkinson’s disease, and discuss key challenges and opportunities in this area of research.

Summary: This Review discusses how induced pluripotent stem cells (iPSCs) provide new opportunities to explore the biology and pathophysiology of lysosomal storage diseases, and how iPSCs have illuminated the role of lysosomes in more common disorders.

Activities of Lysosomal Enzymes in Alloxan-Induced Diabetes in the Mouse

The study investigated a panel of lysosomal enzymes in the liver and kidney tissues in alloxan-induced diabetes in the mouse. The mice were divided into six experimental groups receiving 10% alloxan at a dose of 50 and 75 mg/kg over a period of four, eight, and twelve days; each group was compared with controls receiving 0.9% NaCl. The findings were that diabetes induced by both doses of alloxan was accompanied by significant increases in the lysosomal activities of acid phosphatase and the glycosidases investigated: β-glucuronidase, β-galactosidase, β-glucosidase, and N-acetyl-hexosaminidase. The lysosomal enzyme activity in both liver and kidney cells peaked 12 days after onset of diabetes for most enzymes, at the time when hyperglycemia and hyperinsulinemia already started abating after their peak at 8 days into the course of diabetes. The enzyme activity was in most cases higher with the higher dose of alloxan and thus higher level of glycemia. Lysosomal enzymes degrade glycoconjugates, the molecules that are present in the basement membrane of endothelial cells where they contribute to capillary wall stability. Thus, enhanced activity of these enzymes could presage the progression of diabetic microangiopathy, atherosclerosis, and the development of microvascular complications.

Age and gender-specific reference intervals for lysosomal enzymes in dried blood spot samples: A study in Indian population

OBJECTIVES

The study aimed to establish age and gender-specific reference values for the activities of lysosomal enzymes (acid α-galactosidase [GLA], acid β-glucocerebrosidase [GBA], acid α-glucosidase [GAA], acid sphingomyelinase [ASM] and galactocerebrosidase [GALC]) in dried blood spots (DBS) of Indian population.

DESIGN AND METHODS

A total of 3797 healthy Indian subjects (1456 females and 2341 males) aged from 2days to 60years were selected for the study. Activities of 5 lysosomal enzymes were determined by tandem mass spectrometry, for newborns (<30days), infants (>1month-1year), children (>1-5years) and (>5-18years) and adults (>18years).Variations in enzyme activities based on age and gender were studied. The reference interval was defined as the central 95% range, and was determined based on age and gender.

RESULTS

Highly significant differences in activities were observed for GAA (p=0.001), GLA (p<0.0001), GBA (p<0.0001), ASM (p<0.0001) and GALC (p<0.0001), between different age groups. Comparison of activities between genders showed significant difference for ASM in children aged 1-5years (p=0.03) with higher activity in females, and for GLA in children aged 5-18years (p=0.004) where the activity was higher in males. Reference intervals decreased with age for all enzymes, except GAA. The ranges of GLA and GALC were higher in females, whereas GBA was higher in males.

CONCLUSION

The study establishes age and gender-specific reference values for the screening and identification of lysosomal storage disorders in Indian population. Our data may facilitate establishment of mass screening programs for these disorders in India.

Chlorogenic acid ameliorates isoproterenol-induced myocardial injury in rats by stabilizing mitochondrial and lysosomal enzymes

This study was deliberated to aspire the effects of chlorogenic acid (CGA) against myocardial infarction (MI) induced by Isoproterenol (ISO), in a rat model. In the pathology of MI, enzymes released due to the mitochondrial and lysosomal lipid peroxidation play an integral role. Induction of rats with ISO (85mg/kg BW) for 2 consecutive days resulted in a significant decrease in the activities of heart mitochondrial enzymes isocitrate dehydrogenase (ICDH), α-ketoglutarate dehydrogenase (α-KGDH), succinate dehydrogenase (SDH) and malate dehydrogenase (MDH). The activities of lysosomal enzymes (β- glucosidase, β-glucuronidase, α-galactosidase, β-galactosidase, cathepsin-B and cathepsin-D) were increased significantly in the heart tissue. A prominent expression of LDH 1 and LDH 2 isoenzymes in the serum were observed and changes in the Electrocardiographic (ECG) patterns were also recorded in the ISO-induced rats. The prior administrations of CGA (40mg/kg BW) for 19days markedly ameliorated ISO induced alterations in ECG and significantly restored the activities of all the above enzymes in the heart of ISO-induced rats, which substantiates the stress stabilizing action of CGA. Oral administration of CGA (40mg/kg BW) to normal rats did not show any significant changes. These biochemical functional alterations were supported by the histology of heart (Massion's trichrome and Picrosirius red staining for collagen formation). Thereupon, this study shows that 40mg/kg BW of CGA gives protection against ISO-induced MI and demonstrates that CGA has a significant effect in the protection of heart.

The oxidant-antioxidant equilibrium, activities of selected lysosomal enzymes and activity of acute phase protein in peripheral blood of 18-year-old football players after aerobic cycle ergometer test combined with ice-water immersion or recovery at room temperature

The goal of the study was to evaluate the effect of an aerobic exercise bout followed by ice-water immersion or recovery at room temperature on the redox state, activities of selected lysosomal enzymes and activity of α1-antitrypsin (AAT) in the blood of healthy sportsmen. Eleven amateur football players aged 18 were randomly assigned to two similar 30-min aerobic cycle ergometer tests followed by a recovery at room temperature (20 °C; Experiment 1) or ice-water immersion (3 °C, 5 min; Experiment 2). Peripheral blood was collected three times during both study experiments: before (baseline), as well as 20 and 40 min after the recovery or immersion. The concentrations of thiobarbituric acid reactive substances in blood plasma (plTBARS) and erythrocytes (erTBARS) were measured. The erythrocytic activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were also determined. In the blood serum, the activities of acid phosphatase (AcP), arylsulphatase (ASA), cathepsin D (CTS D) and AAT were evaluated. The activities of AcP, ASA, CTS D and AAT changed similarly during both experiments. The GPx activity decreased 40 min after the exercise/recovery compared to the baseline activity and was lower than 40 min after the exercise/immersion. The exercise followed by the recovery or immersion had no significant effect on the serum lysosomal and AAT activities in the studied men. The exercise/recovery reduced the hydrogen peroxide concentration in the men's erythrocytes, however the exercise/immersion demonstrated the opposite effect.

Inherited Metabolic Disorders: Efficacy of Enzyme Assays on Dried Blood Spots for the Diagnosis of Lysosomal Storage Disorders

High consanguinity rates, poor access to accurate diagnostic tests, and costly therapies are the main causes of increased burden of lysosomal storage disorders (LSDs) in developing countries. Therefore, there is a major unmet need for accurate and economical diagnostic tests to facilitate diagnosis and consideration of therapies before irreversible complications occur. In cross-country study, we utilized dried blood spots (DBS) of 1,033 patients clinically suspected to harbor LSDs for enzymatic diagnosis using modified fluorometric assays from March 2013 through May 2015. Results were validated by demonstrating reproducibility, testing in different sample types (leukocytes/plasma/skin fibroblast), mutation study, or measuring specific biomarkers. Thirty percent (307/1,033) were confirmed to have one of the LSDs tested. Reference intervals established unambiguously identified affected patients. Correlation of DBS results with other biological samples (n = 172) and mutation studies (n = 74) demonstrated 100% concordance in Gaucher, Fabry, Tay Sachs, Sandhoff, Niemann-Pick, GM1, Neuronal ceroid lipofuscinosis (NCL), Fucosidosis, Mannosidosis, Mucopolysaccharidosis (MPS) II, IIIb, IVa, VI, VII, and I-Cell diseases, and 91.4% and 88% concordance in Pompe and MPS-I, respectively. Gaucher and Pompe are the most common LSDs in India and Pakistan, followed by MPS-I in both India and Sri Lanka. Study demonstrates utility of DBS for reliable diagnosis of LSDs. Diagnostic accuracy (97.6%) confirms veracity of enzyme assays. Adoption of DBS will overcome significant hurdles in blood sample transportation from remote regions. DBS enzymatic and molecular diagnosis should become the standard of care for LSDs to make timely diagnosis, develop personalized treatment/monitoring plan, and facilitate genetic counseling.

Efficacy of boswellic acid on lysosomal acid hydrolases, lipid peroxidation and anti-oxidant status in gouty arthritic mice

OBJECTIVE

To evaluate the efficacy of boswellic acid against monosodium urate crystal-induced inflammation in mice.

METHODS

The mice were divided into four experimental groups. Group I served as control; mice in group II were injected with monosodium urate crystal; group III consisted of monosodium urate crystal-induced mice who were treated with boswellic acid (30 mg/kg/b.w.); group IV comprised monosodium urate crystal-induced mice who were treated with indomethacin (3 mg/kg/b.w.). Paw volume and levels/activities of lysosomal enzymes, lipid peroxidation, anti-oxidant status and inflammatory mediator TNF-α were determined in control and monosodium urate crystal-induced mice. In addition, the levels of β-glucuronidase and lactate dehydrogenase were also measured in monosodium urate crystal-incubated polymorphonuclear leucocytes (PMNL) in vitro.

RESULTS

The activities of lysosomal enzymes, lipid peroxidation, and tumour necrosis factor-α levels and paw volume were increased significantly in monosodium urate crystal-induced mice, whereas the activities of antioxidant status were in turn decreased. However, these changes were modulated to near normal levels upon boswellic acid administration. In vitro, boswellic acid reduced the level of β-glucuronidase and lactate dehydrogenase in monosodium urate crystal-incubated PMNL in concentration dependent manner when compared with control cells.

CONCLUSIONS

The results obtained in this study further strengthen the anti-inflammatory/antiarthritic effect of boswellic acid, which was already well established by several investigators.

Thymol attenuates inflammation in isoproterenol induced myocardial infarcted rats by inhibiting the release of lysosomal enzymes and downregulating the expressions of proinflammatory cytokines

Inflammation plays an important role in the development of myocardial infarction (MI). The current study dealt with the protective effects of thymol on inflammation in isoproterenol (ISO) induced myocardial infarcted rats. Male albino Wistar rats were pre and co-treated with thymol (7.5mg/kg body weight) daily for 7 days. ISO (100mg/kg body weight) was injected subcutaneously into rats at an interval of 24h for two days (6th and 7th day) to induce MI. ISO induced myocardial infarcted rats showed increased levels of serum cardiac troponin-T, high sensitive C-reactive protein (hsCRP), lysosomal thiobarbituric acid reactive substances (TBARS) and elevated ST-segments. Also, the activities of lysosomal enzymes such as β-glucuronidase, β-galactosidase, cathepsin-B and D, the stimulators of inflammatory mediators were increased in the serum and heart of ISO induced myocardial infarcted rats. Furthermore, ISO up regulates the expressions of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) genes in the myocardium of rats analyzed by reverse transcription polymerase chain reaction (RT-PCR). Pre and co-treatment with thymol (7.5mg/kg body weight) near normalized the levels of lysosomal TBARS, activities of serum and heart lysosomal enzymes and downregulates the expressions of pro-inflammatory cytokines in the myocardium of ISO induced myocardial infarcted rats. Histopathological and transmission electron microscopic findings were also found in line with biochemical findings. Thus, the results of our study revealed that thymol attenuates inflammation by inhibiting the release of lysosomal enzymes and downregulates the expressions of pro-inflammatory cytokines by its potent anti-inflammatory effect.

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-β-d-glucosaminidase (NAG), arylsulfatase A and β-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.

Picrotoxin-induced convulsions and lysosomal function in the rat brain

The effect of picrotoxin-induced convulsions on lysosomal function in rat brain were evaluated by measuring the free as well as total acid phosphatase, cathepsin D, acid ribonuclease (RNAse II) and acid deoxyribonuclease (DNAse II) activities. Following picrotoxin treatment the free RNAse II activity increased whereas the total activities of practically all the other enzymes decreased. Paradoxically, the cathepsin D activity, free as well the total was completely abolished. In case of all the enzymes the ratio of Total activity/Free activity decreased indicating increased lysosomal membrane fragility which could lead to process of neurodegeneration in the epileptic animals.

Significance and prognostic value of lysosomal enzyme activities measured in surgically operated adenocarcinomas of the gastroesophageal junction and squamous cell carcinomas of the lower third of esophagus

AIM: To establish whether there are fundamental differences in the biochemistries of adenocarcinomas of the gastroesophageal junction (GEJ) and the squamous cell carcinomas of the lower third of the esophagus (LTE).

METHODS: Between February 1, 1997 and February 1, 2000, we obtained tissue samples at the moment of resection from 54 patients for biochemical analysis. The full set of data could be comprehensively analyzed in 47 of 54 patients samples (81%). Of these, 29 were adenocarcinomas of the GEJ Siewert type I (n = 8), type II (n = 12), type III (n = 9), and 18 presented as squamous cell carcinomas of the LTE. We evaluated the mean values of 11-lysosomal enzyme and 1-cytosol protease activities of the tumorous and surrounding mucosae as well as their relative activities, measured as the ratio of activity in tumor and normal tissues from the same patient. These data were further analyzed to establish the correlation with tumor localization, TNM stage (lymph-node involvement), histological type (papillary, signet-ring cell, tubular), state of differentiation (good, moderate, poor), and survival (≤ 24 or ≥ 24 mo).

RESULTS: In adenocarcinomas, the activity of α-mannosidase (AMAN), cathepsin B (CB) and dipeptidyl-peptidase I (DPP I) increased significantly as compared to the normal gastric mucosa. In squamous cell carcinomas of the esophagus, we also found a significant difference in the activity of cathepsin L and tripeptidyl-peptidase I in addition to these three. There was a statistical correlation of AMAN, CB, and DPP I activity between the level of differentiation of adenocarcinomas of the GEJ and lymph node involvement, because tumors with no lymph node metastases histologically confirmed as well-differentiated, showed a significantly lower activity. The differences in CB and DPP I activity correlated well with the differences in survival rates, since the CB and DPP I values of those who died within 24 mo following surgical intervention were significantly higher than of those who survived for 2 years or more.

CONCLUSION: Adenocarcinomas of the GEJ form a homogenous group from a tumor-biochemical aspect, and differ from the biochemical characteristics of squamous cell carcinomas of the LTE on many points. When adenocarcinomas of the GEJs are examined at the preoperative phase, the ratio of the performed AMAN, CB, and DPP I enzymatic activity of the tissue sample from the tumor and adjacent intact mucosa within2 cm of the tumor may have a prognostic value even in the preoperative examination period, and may indicate that ranking of these patients into the neo-adjuvant treatment group should be considered.

Metabolic changes in the lower esophageal sphincter influencing the result of anti-reflux surgical interventions in chronic gastroesophageal reflux disease

AIM: With the availability of a minimally invasive approach, anti-reflux surgery has recently experienced a renaissance as a cost-effective alternative to life-long medical treatment in patients with gastroesophageal reflux disease (GERD). We are not aware of the fact whether reflux episodes causing complaints for a long time i.e., at least for one year are associated with metabolic changes in the lower esophageal sphincter, and if so, whether these may influence functional results achieved after anti-reflux surgery.

METHODS: Between 1 January 2001 and 31 December 2002 we performed anti-reflux surgery on 79 patients. Muscle samples were taken from the lower esophageal sphincter (LES) in 33 patients during anti-reflux surgery. Inclusion criteria were: LES resting pressure below 10 mmHg and a marked, pH proven acid exposure to the esophagus of at least one year’ duration, causing subjective complaints and requiring continuous proton pump inhibitor treatment. Control samples were obtained from muscle tissue in the gastroesophageal junction that had been removed from 17 patients undergoing gastric or esophageal resection. Metabolic and lysosomal enzyme activities and special protein concentrations 16 parameters in total were evaluated in tissue taken from control specimens and tissue taken from patients with GERD. The biochemical parameters of these intra-operative biopsies were used to correlate the results of anti-reflux operations (Visick I and II-III).

RESULTS: In the reflux-type muscle, we found a significant increase of the energy-enzyme activities e.g., creatine kinase, lactate dehydrogenase, β-hydroxybutyrate dehydrogenase, and aspartate aminotransaminase-. The concentration of the structural protein S-100 and the myofibrillar protein troponin I were also significantly increased. Among lysosomal enzymes, we found that the activities of cathepsin B, tripeptidyl-peptidase I, dipeptidyl-peptidase II, β-hexosaminidase B, β-mannosidase and β-galactosidase were significantly decreased as compared to the control LES muscles. By analyzing the activity values of the 9 patients in Visick groups II and III at two months post-surgery, we found a significant increase in the activity of the so-called energy-enzyme values and in the concentration of structural and myofibrillar proteins as compared to the rest of the reflux patients.

CONCLUSION: Our results call attention to the metabolic changes that occurred in the LES muscles of reflux patients. The developing hypertrophy-like changes of LES muscles may be a reason for complaints after anti-reflux surgery, which consisted mainly of reports of persisting dysphagia.