Erythrocyte Arginase Activity Research Articles

Evaluation of erythrocyte arginase activity, plasma nitric oxide concentration and oxidative stress status in cattle with anaplasmosis

Bovine anaplasmosis is an arthropod-borne disease characterized by high fever, anaemia and sometimes jaundice. The role of oxidative stress in anaplasmosis has been investigated, but erythrocyte arginase (ARG) activity has not been studied. In this study, we aimed to investigate the changes in haematological parameters, erythrocyte ARG activity, plasma nitric oxide (NO) levels and oxidative stress parameters and explain the relationship between each other in cattle with anaplasmosis. The material of this study consisted of 14 cattle, aged 10–12 months with anaplasmosis (infected group) and 14 healthy cattle aged 10–12 months (control group). Our data revealed that leukocyte parameters and plasma NO levels and serum malondialdehyde (MDA), total oxidant status (TOS) and oxidative stress index (OSI) levels were higher while erythrocyte parameters, erythrocyte ARG activity and serum total antioxidant status (TAS) and glutathione (GSH) levels were lower in the infected group compared to the control group. There was a strong correlation between erythrocyte ARG activity and NO, MDA, TOS, OSI, TAS and GSH. ROC analysis and correlation results suggest that erythrocyte ARG activity is an effective oxidative stress marker. We concluded that severe oxidative stress occurs in anaplasmosis. As the severity of anaemia increases, erythrocyte ARG activity plummets while plasma NO level elevates. These two parameters may also be used as prognostic and oxidative stress markers. Although decreased erythrocyte ARG activity is a disadvantage in haemolytic diseases, this situation can be compensated by increased NO. Thus, homeostasis of these two parameters may contribute to the elimination of the infection.

Assessment of plasma nitric oxide concentration and erythrocyte arginase activity in dairy cows with traumatic reticuloperitonitis

The aim of this study was to evaluate plasma nitric oxide (NO) concentrations, erythrocyte arginase (ARG) activity, plasma fibrinogen (Fb) and serum iron (Fe) levels and some biochemical parameters in dairy cows with traumatic reticuloperitonitis (TRP). The animal material of the study consisted of 14 Swiss Brown cows diagnosed with TRP (TRP group) between 4-8 years old brought to Firat University Animal Hospital Clinics and 14 healthy Swiss Brown cows (control group) aged 4-8 years obtained from dairy farms in different regions. Blood samples were taken from the vena jugularis of the animals. Concentrations of plasma NO, Fb, erythrocyte ARG activity, and some biochemical markers were determined after the serum and plasma of the receiving blood were separated. While the NO (318.9±5.8 vs. 270.3±9.6 μmol/L) concentrations of the TRP group were found to be significantly higher than the control group (P<0.001), the erythrocyte ARG activity (29.5±0.5 vs. 35.2±1.0 U/hb) was found to be higher in the control group (P<0.001). It was also observed that total protein (TP) (6.6±0.5 vs. 7.8±0.1 g/dL) (P<0.05) and Fb (914.3±68.6 vs. 265.4±19.8 mg/dL) (P<0.001) concentrations were higher in the TRP group, compared to the control group, while albumin (ALB) (1.9±0.2 vs. 3.1±0.1 g/dL) and Fe (47.00±5.29 vs.106.79±9.44 μg/dL) concentrations were significantly lower than the control group (P<0.001). In addition, a positive correlation was found between NO and Fb concentrations and between erythrocyte ARG activity and Fe concentrations. As a result, it was determined that NO concentrations were increased and erythrocyte ARG activity was not significant in dairy cows with TRP. In addition, increased plasma Fb concentration and decreased serum Fe concentration were determined in dairy cows with TRP. This study demonstrated that plasma NO, Fb and serum Fe concentrations in dairy cows with TRP may be useful markers for prognosis.

Role of Myeloperoxidase, Paraoxonase, and Nitric Oxide System in the Blood and Pericardial Fluid of Patients with Ischemic Heart Disease after Direct Myocardial Revascularization

To study the role of paraoxonase, myeloperoxidase, arginase, asymmetric dimethylarginine, and nitric oxide in the mechanisms of the pathogenesis of postpericardiotomy syndrome (PPCS), 76 patients with ischemic heart disease (IHD) who underwent coronary artery bypass grafting were examined. Patients were divided into two groups: Group 1, IHD patients who were not diagnosed with PPCS as a result of clinical studies, and Group 2, IHD patients who were diagnosed with PPCS. The results indicate that the postoperative period after coronary artery bypass grafting is associated with the inhibition of paraoxonase, the activation of myeloperoxidase, enhanced arginase activity, increased nitrite/nitrate and asymmetric dimethylarginine levels; it may also be accompanied by the development of endothelial dysfunction and increased systemic inflammatory response. In the present work, inverse correlations were found between the paraoxonase aryl esterase activity and myeloperoxidase activity in plasma, as well as the paraoxonase aryl esterase activity in blood plasma and arginase activity in erythrocytes in patients of both groups. Tests to predict the development of postpericardiotomy syndrome were developed based on the ratio of activity of the studied enzymes.

Preeclampsia is associated with increased erythrocyte arginase activity and compromised nitric oxide bioactivity compared with healthy pregnant women

Preeclampsia is associated with increased erythrocyte arginase activity and compromised nitric oxide bioactivity compared with healthy pregnant women

Evaluation of arginase activity, nitric oxide and oxidative stress status in sheep with contagious agalactia.

It is known that inflammatory organ damages due to various agents, such as microorganisms including mycoplasmas, lead to oxidative stress. Nitric oxide (NO) functions as an antimicrobial agent, and arginase decreases proinflammatory cytokine release. There are very few studies on arginase activity, NO level and oxidative stress status in mycoplasmal infections. Therefore, the aim of this study was to evaluate erythrocyte arginase activity, plasma NO level and oxidative stress status in sheep with contagious agalactia. The study material consisted of 10 healthy sheep and 14 sheep with contagious agalactia characterised by mastitis, arthritis and keratoconjunctivitis. Erythrocyte arginase activity, plasma NO, malondialdehyde (MDA), total oxidant capacity (TOC) and total antioxidant capacity (TAC) levels were measured. Significant decreases in erythrocyte arginase activity and plasma TAC level (P < 0.001), and significant increases in plasma NO, MDA and TOC levels (P < 0.001) were found in the diseased sheep as compared with the healthy animals. This study suggests that contagious agalactia may cause oxidative stress due to increased plasma MDA and TOC levels and decreased plasma TAC levels, and that the decrease in erythrocyte arginase activity and increase in plasma NO level may contribute to the elimination of mycoplasmal agents causing contagious agalactia.

Five Novel Mutations in ARG1 Gene in Chinese Patients of Argininemia

Argininemia is an autosomal recessive genetic disorder caused by hepatocyte arginase deficiency. It could be detected by blood amino acids analysis (high arginine) and confirmed by molecular diagnosis. The clinical manifestations in patients are similar to cerebral palsy so the diagnosis is usually much delayed. Reports of argininemia from mainland China are few, and genetic analyses have not been reported. Five Chinese patients with argininemia were investigated. They had progressive spastic tetraplegia, poor physical growth from 1 month to 4 years. When argininemia was found at the ages of 4 to 12 years, four of patients had mental retardation, and three had seizures. Elevated blood arginine and significantly decreased erythrocyte arginase activity in five patients confirmed the diagnosis of arginase deficiency. Liver dysfunction was found in four patients, two of whom had mildly elevated blood ammonia levels. Cranial magnetic resonance imaging showed progressive cerebral atrophy in three patients. Six mutations in the ARG1 gene were identified, of which only one (c.703 G>A, p.G235R) in exon 7 has been reported before; c.34 G>T (p.G12X) in exon 1, c.67delG (p.G23fsX31) in exon 2, c.539G>C (p.R180 T) in exon 5, c.374C>T (p.A125 V) in exon 4, and c.646-649del CTCA (p.T215fsX219) in exon 6 were novel mutations. Argininemia is one of the few treatable causes of pediatric spastic paraparesis. Early metabolic investigation is very important to reach a diagnosis and better outcome. Five Chinese patients with late-diagnosed argininemia were reported. The mutation spectrum of ARG1 gene should be different from other populations.

English

Down syndrome is a chromosome abnormality with specific clinical symptoms and mental retardation caused by trisomy of chromosome 21. There is evidence that oxygen free radicals play an important role in the pathophysiology of many neuropsychiatric disorders. Although, it has not been investigated yet, several recent studies proposed that&nbsp;nitric oxide&nbsp;related to oxidative stress and arginase may have a pathophysiological role in mental retardation. The purpose of this study was to determine&nbsp;plasma&nbsp;nitric oxide&nbsp;levels&nbsp;and erythrocyte arginase activities in patients with Down syndrome and in healthy children. Plasma nitric oxide levels and erythrocyte arginase activity were measured in 20 patients with Down syndrome (median age: 15.6 &plusmn; 7.5) and 20 age-matched healthy subjects (median age: 16.2 &plusmn; 7.4). Significant differences were found between erythrocyte arginase activity of the patients with Down syndrome (35.2 &plusmn; 2.7 U/g hemoglobin (Hb)) and those of healthy children (43.5 &plusmn; 2.9 U/g Hb), (P &lt; 0.05). But we have not found any statistical difference between persons with Down syndrome and control group for nitric oxide (P &gt; 0.05). It was concluded that the level of erythrocyte arginase activity could be considered as a useful marker for assessing the level of mental retardation in children with Down syndrome. &nbsp; Key words:&nbsp;Down syndrome, erythrocyte arginase, nitric oxide, mental retardation, oxidative stress.

Impacts of Lisinopril and Lisinopril Plus Simvastatin on Erythrocyte and Plasma Arginase, Nitrite, and Nitrate in Hypertensive Patients

Angiotensin-converting enzyme inhibitors are effective at reducing blood pressure, whereas statins decrease plasma cholesterol, impeding atherosclerosis. The authors hypothesize that these medications may improve blood pressure by modifying the arginase-nitric oxide synthase system of erythrocytes. In this study, the effects of lisinopril alone versus lisinopril + simvastatin on erythrocyte and plasma arginase enzyme and nitric oxide metabolites are compared. Patients with atherosclerosis and hypertension are randomly assigned to receive lisinopril 10 to 20 mg/d or lisinopril 10 to 20 mg/d plus simvastatin 20 mg/d for 24 weeks. Higher arginase activity is observed in erythrocytes from 100% of patients and mainly recovered after 12 and 24 weeks of treatment with lisinopril or lisinopril + simvastatin. Plasma arginase activity is 3 orders of magnitude lower than erythrocyte arginase activity in all participants, suggesting a lack of its clinical significance. Both treatments cause the increase in plasma $$\hbox{ N }{\hbox{ O }}_{2}^{-}$$ , $$\hbox{ N }{\hbox{ O }}_{3}^{-}$$ , and $$\hbox{ N }{\hbox{ O }}_{2}^{-}$$ + $$\hbox{ N }{\hbox{ O }}_{3}^{-}$$ in 100% of patients. Erythrocyte $$\hbox{ N }{\hbox{ O }}_{2}^{-}$$ + $$\hbox{ N }{\hbox{ O }}_{3}^{-}$$ concentration is greatly decreased in hypertensive patients but recovers after monotherapy and combined therapy. The results show for the first time that lisinopril monotherapy and combined lisinopril + simvastatin therapy exhibit pronounced and equipotential normalizing effects on erythrocyte arginase and nitric oxide synthase activities.

Arginase, nitrates, and nitrites in the blood plasma and erythrocytes in hypertension and after therapy with lisinopril and simvastatin

Arginase activity in erythrocytes is higher in patients with arterial hypertension and atherosclerosis as compared with healthy people. Therapy with either lisinopril alone or in combination with simvastatin for 3-6 months causes a decrease in the arginase activity to the control level. Both the monotherapy and the combination therapy increased the concentrations of NO2(-), NO3(-), and total NOO2(-) + NO3(-)in the plasma of hypertensive patients. The NO2(-) + NO3(-) concentration in erythrocytes decreases in hypertensive patients but is completely restored after therapy with lisinopril alone or in combination with simvastatin. Thus, lisinopril and lisinopril plus simvastatin display a pronounced and equal normalizing effect on arginase activity in human erythrocytes, which is elevated in hypertension, as well as on the endothelial nitric oxide synthase activity, which is decreased in hypertension.

ROLE OF MATERNAL ERYTHROCYTE ARGINASE ACTIVITY IN PREGNANCY – A PILOT STUDY

Abstract Introduction Arginase is an urea cycle enzyme which catalyzes the cleavage of L arginine to L- ornithine and urea. It is expressed in liver, erythrocyte, brain, kidney, mammary gland and intestine. The arginase activity detected in nonhepatic tissues that lacka complete set of urea cycle enzymes is thought to provide ornithine, the biosynthetic precursor of proline, an important constituent of collagen, andthe polyamines, which are important for cell proliferation. Aim and objectives In the current study arginase level in maternal erythrocytes were determined to ascertain any possible role in pregnancy. Study design The study group comprised of total 45 subjects including twenty non – pregnant women (mean age 31.0 ± 6.0 years) and twenty five pregnant women (mean age 29.6 ± 6.1 years) of gestational age between 28 – 38 weeks. Results We found a significant increase in the level of maternal erythrocyte arginase (p 0.05) in pregnant women when compared to non – pregnant women. Conclusion Our study suggests that the increased maternal erythrocyte arginase activity may have a role in fetal growth and development.

Arginase Deficiency Presenting as Intractable Hiccups With Severe Hyperammonemia at One Month of Age

Arginase deficiency is a rare urea cycle disorder and generally presents in children of preschool age with developmental delay and spasticity. Unlikely other urea cycle defects, patients rarely present hyperammonemic symptoms, especially in the early infantile period. A one-month-old male infant was admitted to our hospital because of abnormal respiratory condition with persistent hiccups and lethargy. The initial laboratory studies showed respiratory alkalosis and remarkable hyperammonemia [ammonia, 1970 ? mol/L (25 times normal)]. Amino acid chromatography showed a markedly elevated plasma arginine level (1131 µ mol/L; 10 times normal), and erythrocyte arginase activity was undetectable. Despite prompt diagnosis and normalization of ammonia and arginine levels by peritoneal dialysis, the patient developed neurodevelopmental impairment during the one-year follow-up period. In summary, this is a rare case of arginase deficiency in terms of early infantile onset and presentation of the severe form of hyperammone mia. Pathologic hiccups could be one of the clinical clues to the presence of hyperammonemia even in young infants with arginase deficiency. doi:10.4021/jmc141w

Increased Platelet and Erythrocyte Arginase Activity in Chronic Obstructive Pulmonary Disease Associated With Tobacco or Wood Smoke Exposure

BackgroundChronic obstructive pulmonary disease (COPD) is an inflammatory disease that is characterized by a progressive and irreversible decline in lung function and is caused primarily by chronic exposure to tobacco...

Arginase Deficiency Presenting as Intractable Hiccups With Severe Hyperammonemia at One Month of Age

Arginase deficiency is a rare urea cycle disorder and generally presents in children of preschool age with developmental delay and spasticity. Unlikely other urea cycle defects, patients rarely present hyperammonemic symptoms, especially in the early infantile period. A one-month-old male infant was admitted to our hospital because of abnormal respiratory condition with persistent hiccups and lethargy. The initial laboratory studies showed respiratory alkalosis and remarkable hyperammonemia [ammonia, 1970 µmol/L (25 times normal)]. Amino acid chromatography showed a markedly elevated plasma arginine level (1131 µmol/L; 10 times normal), and erythrocyte arginase activity was undetectable. Despite prompt diagnosis and normalization of ammonia and arginine levels by peritoneal dialysis, the patient developed neurodevelopmental impairment during the one-year follow-up period. In summary, this is a rare case of arginase deficiency in terms of early infantile onset and presentation of the severe form of hyperammonemia. Pathologic hiccups could be one of the clinical clues to the presence of hyperammonemia even in young infants with arginase deficiency. J Med Cases. 2011;2(2):67-70 doi: https://doi.org/10.4021/jmc141w

Corrigendum.

The following Corrigendum from the British Journal of Haematology, published online in Wiley Online Library (http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2141.2010.08188.x/pdf) on 22 March 2010 and in Volume 149, issue 2, page 307, has been retracted by the Journal Editor-in-Chief, Professor Finbarr Cotter, and Blackwell Publishing Ltd. The retraction has been made because it was subsequently determined that Mr Syed Jamal was never involved in the project that resulted in the original publication listed below. -- Iyamu, E.W., Jamal, S., Ekekezie, C. & Woods, G.M. (2007) In vitro evidence of the inhibitory capacity of chloroquine on arginase activity in sickle erythrocytes. British Journal of Haematology, 139, 337–343.

A colorimetric microplate assay method for high-throughput analysis of arginase activity in vitro

Several analytical methods have been developed for the determination of arginase ( l-arginine amidinohydrolase) activity in physiological samples. These methods are limited by the considerable effort and time required to obtain reliable and reproducible measurements. Here we describe a simple high-throughput colorimetric assay for the determination of arginase activity based on the ornithine–ninhydrin reaction. This method is an improvement over the original single cuvette assay developed by Chinard in that no boiling step is required. The turnaround time has been reduced, with improved precision and reproducibility. The method was extended to the determination of arginase activity in human leukemic (K562) cells and sickle erythrocytes. We believe that the method will find applications for routine analysis as well as for characterizing the action of novel and potent inhibitors on arginase activity.

Cocoa flavanols lower vascular arginase activity in human endothelial cells in vitro and in erythrocytes in vivo

The availability of l-arginine can be a rate-limiting factor for cellular NO production by nitric oxide synthases (NOS). Arginase competes with NOS for l-arginine as the common substrate. Increased arginase activity has been linked to low NO levels, and an inhibition of arginase activity has been reported to improve endothelium-dependent vasorelaxation. Based on the above, we hypothesized that an increase in the circulating NO pool following flavanol consumption could be correlated with decreased arginase activity. To test this hypothesis we (a) investigated the effects of (−)-epicatechin and its structurally related metabolites on endothelial arginase expression and activity in vitro; (b) evaluated the effects of dietary flavanol-rich cocoa on kidney arginase activity in vivo; and (c) assessed human erythrocyte arginase activity following flavanol-rich cocoa beverage consumption in a double-blind intervention study with cross-over design. The results demonstrate that cocoa flavanols lower arginase-2 mRNA expression and activity in HUVEC. Dietary intervention with flavanol-rich cocoa caused diminished arginase activity in rat kidney and, erythrocyte arginase activity was lowered in healthy humans following consumption of a high flavanol beverage in vivo.

In vitro evidence of the inhibitory capacity of chloroquine on arginase activity in sickle erythrocytes.

Increased levels of erythrocyte arginase activity are believed to play a key role in the pathogenesis of sickle cell disease (SCD). Because increased arginase activity has been implicated in the exacerbation of pulmonary hypertension in SCD, this enzyme is considered an important therapeutic target for identifying new drugs to treat and manage SCD and other inflammatory disorders. Although chloroquine (CQ) is prescribed as an anti-malarial and anti-rheumatoid drug, the mechanism of its anti-inflammatory activity is largely unknown. The present study found that CQ inhibited arginase in a dose-dependent manner, and also displayed a linear competitive inhibition on sickle erythrocyte arginase. The apparent K(M) values in the presence of inhibitor were considerably reduced at both physiological and slightly acidic pHs. Slope replots of the double reciprocal plots at pH 6.8 and 7.4 also indicated simple competitive inhibitory mechanism of CQ, and Ki values for CQ were within micromolar levels. To our knowledge, this is the first example of an anti-malarial and anti-inflammatory agent displaying competitive inhibition kinetics on arginase. The outcome of this study may provide a template for the rational design of specific agents either alone or in combination with CQ for the inhibition of arginase activity.

Pulmonary Hypertension in Thalassemia: Association with Hemolysis, Arginine Metabolism Dysregulation, and a Hypercoagulable State

Pulmonary Hypertension in Thalassemia: Association with Hemolysis, Arginine Metabolism Dysregulation, and a Hypercoagulable State

Modulation of erythrocyte arginase activity in sickle cell disease patients during hydroxyurea therapy

An elevated erythrocyte arginase activity with a corresponding decrease in nitric oxide (NO) level has been implicated in the pathophysiology of sickle cell disease (SCD). Recent studies have shown that hydroxyurea (HU) increases the production of NO, which increases the soluble guanylate cyclase activity and fetal haemoglobin (HbF) synthesis. To study the effects of HU on the arginase and nitric oxide synthase (NOS) activities in SCD patients, we compared levels of arginase activity and NO metabolites in red blood cells and plasma, respectively, from 23 patients with SCD (HbSS) receiving HU therapy, with those of 12 SCD patients not receiving HU treatment. Patients on HU therapy showed significantly lower arginase activity than that of HbSS patients not on HU therapy (1.36+/-0.2 U/10(8) cells vs. 3.31+/-0.29 U/10(8) cells). NOS activity was higher in patients on HU therapy than in untreated patients (0.72+/-0.4 nmol/ml/min vs. 0.35+/-0.15 nmol/ml/min, P<0.05). Among the HU-treated patients, the decreased level of arginase activity correlated (r=0.71) with HbF level as well as the mean corpuscular haemoglobin content. These data suggest that one of the beneficial effects of HU in vivo may involve the regulation of arginase activity and a concomitant induction of NOS activity, which may lead to an increased production of NO. The outcome of this study may lead to the development of improved NO-based treatments for SCD.

The Arginine-to-Ornithine Ratio: Biomarker of Arginase Activity and Predictor of Mortality in Sickle Cell Disease.

Sickle cell disease (SCD) is characterized by a state of nitric oxide resistance and limited bioavailability of L-arginine, the substrate for nitric oxide synthesis. While nitric oxide resistance occurs secondary to inactivation of nitric oxide by plasma hemoglobin released during intravascular hemolysis and by reactive oxygen species, mechanisms that limit L-arginine are not known. We hypothesized that increased arginase activity in patients with SCD would shift arginine metabolism away from nitric oxide production and towards ornithine metabolism, contributing to endothelial dysfunction and the development of pulmonary hypertension. Furthermore, since arginine and ornithine compete for the same transport system for cellular uptake, a decrease in the Arginine-to-Ornithine ratio resulting from increased arginase activity could also impair arginine bioavailability for nitric oxide production. Our goal was to evaluate associations between plasma arginase, arginine metabolism and pulmonary hypertension and prospective mortality in SCD. Plasma and erythrocyte arginase activity and amino acid levels were determined for patients with SCD and compared to ethnically matched control subjects. A diagnosis of pulmonary hypertension by Doppler-echocardiogram and prospective mortality were determined over 30 months of sequential patient enrollment. Plasma arginase activity was significantly elevated in patients with SCD compared to controls (2.2±2, n=140 vs. 0.4±2 μmol/ml/hr, n=45, p=0.007), trending higher in subjects with pulmonary hypertension. Plasma arginase activity correlated with the Arginine-to-Ornithine ratio (r=−0.33, p=0.0004), and lower ratios were associated with greater severity of pulmonary hypertension (1.1±0.4 vs. 0.8±0.4 vs. 0.6±0.3, controls vs. SCD without pulmonary hypertension vs. SCD with pulmonary hypertension, respectively, p=0.01) and independently associated with mortality (0.7±0.4 vs. 0.5±0.2, alive vs. dead, p=0.003; Risk Ratio = 4.9 [CI: 1.4, 17.1], p=0.002, for a low Arginine-to-Ornithine ratio; 13 deaths total). The mortality risk ratio increased to 7.0 ([CI: 1.6, 31.6], p=0.01), when the Arginine-to-Ornithine ratio was adjusted for creatinine, likely reflecting the impact of renal disease. Plasma arginase activity correlated with markers of increased hemolytic rate, including LDH (r=0.44, p<0.001), AST (r=0.39, p<0.002), reticulocyte count (r=0.25, p<0.001), and Hct (r= −0.25, p<0.001), and was higher in erythrocytes of SCD patients compared to controls (37.7±2.9, n=16 vs 23.5±1.7 nmol/mg/min, n=45, p<0.0001), consistent with hemolytic release of erythrocyte arginase. These data support a novel mechanism of disease whereby hemolysis not only liberates vasoactive hemoglobin but also releases erythrocyte arginase, which contributes to impaired nitric oxide bioavailability, endothelial dysfunction, pulmonary hypertension and death. The Arginine-to-Ornithine ratio, a reflection of arginase activity, may represent a useful biomarker of disease severity and risk of death in patients with SCD.