Oxidant and antioxidant of arylesterase and paraoxonase as biomarkers in patients with hepatitis C virus

Exploring the Relationship between Canine Paraoxonase-1 (PON-1) Serum Activity and Liver Disease Classified by Clinico-Pathological Evaluation

Paraoxonase-1 (PON-1), a liver-synthesized enzyme, acts as a negative acute-phase reactant during systemic inflammation in dogs. Given the hepatic synthesis of this enzyme, the presence of liver diseases may influence PON-1, thus affecting its reliability as a biomarker for inflammatory/oxidative systemic diseases. The aim of this study is to investigate PON-1 activity variations among dogs suspected of liver injury or failure, evaluating the influence of hepatic diseases on PON-1 activity. A total of one-hundred-sixty dogs were retrospectively enrolled and categorized into three groups based on clinical presentation and laboratory results: control (C = 20), suspected liver injury (INJ = 114), and suspected liver failure (FAIL = 26). The INJ group was further divided into subgroups based on the severity of the alanine aminotransferase (ALT) increase. Both the INJ and FAIL groups were further divided based on serum macroscopic appearance. The PON-1 activity was quantified using a paraoxon-based method, which is already validated in dogs. No significant difference in PON-1 activity was observed between the C and INJ groups, despite a significant increase in the subgroups with moderate and severe elevations of ALT. The dogs with icteric serum exhibited decreased PON-1 activity, while lipemic serum was associated with an increased PON-1 activity. A significant reduction in PON-1 activity was noted in the FAIL group, compared to both C and INJ groups (p < 0.0001), regardless of serum appearance. Given the retrospective nature of this study, additional evaluations (e.g., histopathology, imaging) were not performed. The results obtained here suggest the importance of interpreting PON-1 activity cautiously in dogs with suspected liver disease.

Paraoxonase-1: How a xenobiotic detoxifying enzyme has become an actor in the pathophysiology of infectious diseases and cancer

Both infectious and non-infectious diseases can share common molecular mechanisms, including oxidative stress and inflammation. External factors, such as bacterial or viral infections, excessive calorie intake, inadequate nutrients, or environmental factors, can cause metabolic disorders, resulting in an imbalance between free radical production and natural antioxidant systems. These factors may lead to the production of free radicals that can oxidize lipids, proteins, and nucleic acids, causing metabolic alterations that influence the pathogenesis of the disease. The relationship between oxidation and inflammation is crucial, as they both contribute to the development of cellular pathology. Paraoxonase 1 (PON1) is a vital enzyme in regulating these processes. PON1 is an enzyme that is bound to high-density lipoproteins and protects the organism against oxidative stress and toxic substances. It breaks down lipid peroxides in lipoproteins and cells, enhances the protection of high-density lipoproteins against different infectious agents, and is a critical component of the innate immune system. Impaired PON1 function can affect cellular homeostasis pathways and cause metabolically driven chronic inflammatory states. Therefore, understanding these relationships can help to improve treatments and identify new therapeutic targets. This review also examines the advantages and disadvantages of measuring serum PON1 levels in clinical settings, providing insight into the potential clinical use of this enzyme.

Elevation of Myeloperoxidase Correlates with Disease Severity in Patients with Hantaan Virus Infection

Hantaan orthohantavirus (HTNV) can cause hemorrhagic fever with renal syndrome (HFRS) characterized by acute kidney injury and hemorrhage. Neutrophils are the most abundant innate immune cell and the body's first line of defense against pathogens. Currently, an increasing number of studies have shown that neutrophils may be a mixed blessing in terms of viral infections. However, the role of neutrophils in HFRS patients with HTNV infection has not been fully declared. In this study, we analyzed plasma levels of both myeloperoxidase (MPO) and MPO-DNA in HFRS patients, together with the clinical parameters. Neutrophil-platelet aggregates (NPAs) during the acute and convalescent phases of HFRS were also assessed. The results showed that plasma MPO-DNA levels had no change in different disease phases or severities of HFRS patients. Whereas plasma MPO significantly increased in the acute phase and critical/severe groups of HFRS patients. Furthermore, plasma MPO was positively correlated with inflammatory clinical parameters, such as white blood cell counts, neutrophil counts, and renal injury-related parameters, such as blood urea nitrogen, blood uric acid, and serum creatinine, as well as negatively correlated with and platelet counts. In addition, NPAs increased both in acute and convalescent phase in HFRS patients compared with normal controls. These results suggested that elevated plasma MPO in HFRS patients correlated with disease severity, together with the increases of NPAs in HFRS patients, which may provide new insights into potential role of neutrophils in the pathogenesis of HFRS.

Paraoxonase-1 Facilitates PRRSV Replication by Interacting with Viral Nonstructural Protein-9 and Inhibiting Type I Interferon Pathway

Paraoxonase-1 (PON1), an esterase with specifically paraoxonase activity, has been proven to be involved in inflammation and infection. Porcine reproductive and respiratory syndrome virus (PRRSV) is still a major concern in pigs and causes severe economic losses to the swine industry worldwide. In this study, the role of PON1 was investigated in porcine alveolar macrophages (PAMs) during PRRSV infection. The results showed that PRRSV replication downregulated PON1, and the knockdown of PON1 significantly decreased PRRSV replication. Similarly, PON1 overexpression could enhance PRRSV replication. Interestingly, we observed that PON1 interacted with PRRSV nonstructural protein 9 (Nsp9), the RNA-dependent RNA polymerase, and the knockdown of PON1 lowered the RNA binding ability of Nsp9, suggesting that PON1 can facilitate Nsp9 function in viral replication. In addition, the knockdown of PON1 expression led to the amplification of type I interferon (IFN) genes and vice versa. In summary, our data demonstrate that PON1 facilitates PRRSV replication by interacting with Nsp9 and inhibiting the type I IFN signaling pathway. Hence, PON1 may be an additional component of the anti-PRRSV defenses.

The Current Status of Research on High-Density Lipoproteins (HDL): A Paradigm Shift from HDL Quantity to HDL Quality and HDL Functionality

The quantity of high-density lipoproteins (HDL) is represented as the serum HDL-C concentration (mg/dL), while the HDL quality manifests as the diverse features of protein and lipid content, extent of oxidation, and extent of glycation. The HDL functionality represents several performance metrics of HDL, such as antioxidant, anti-inflammatory, and cholesterol efflux activities. The quantity and quality of HDL can change during one's lifetime, depending on infection, disease, and lifestyle, such as dietary habits, exercise, and smoking. The quantity of HDL can change according to age and gender, such as puberty, middle-aged symptoms, climacteric, and the menopause. HDL-C can decrease during disease states, such as acute infection, chronic inflammation, and autoimmune disease, while it can be increased by regular aerobic exercise and healthy food consumption. Generally, high HDL-C at the normal level is associated with good HDL quality and functionality. Nevertheless, high HDL quantity is not always accompanied by good HDL quality or functionality. The HDL quality concerns the morphology of the HDL, such as particle size, shape, and number. The HDL quality also depends on the composition of the HDL, such as apolipoproteins (apoA-I, apoA-II, apoC-III, serum amyloid A, and α-synuclein), cholesterol, and triglyceride. The HDL quality is also associated with the extent of HDL modification, such as glycation and oxidation, resulting in the multimerization of apoA-I, and the aggregation leads to amyloidogenesis. The HDL quality frequently determines the HDL functionality, which depends on the attached antioxidant enzyme activity, such as the paraoxonase and cholesterol efflux activity. Conventional HDL functionality is regression, the removal of cholesterol from atherosclerotic lesions, and the removal of oxidized species in low-density lipoproteins (LDL). Recently, HDL functionality was reported to expand the removal of β-amyloid plaque and inhibit α-synuclein aggregation in the brain to attenuate Alzheimer's disease and Parkinson's disease, respectively. More recently, HDL functionality has been associated with the susceptibility and recovery ability of coronavirus disease 2019 (COVID-19) by inhibiting the activity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The appearance of dysfunctional HDL is frequently associated with many acute infectious diseases and chronic aging-related diseases. An HDL can be a suitable biomarker to diagnose many diseases and their progression by monitoring the changes in its quantity and quality in terms of the antioxidant and anti-inflammatory abilities. An HDL can be a protein drug used for the removal of plaque and as a delivery vehicle for non-soluble drugs and genes. A dysfunctional HDL has poor HDL quality, such as a lower apoA-I content, lower antioxidant ability, smaller size, and ambiguous shape. The current review analyzes the recent advances in HDL quantity, quality, and functionality, depending on the health and disease state during one's lifetime.

LDL particle size and antioxidant HDL function improve after sustained virological response in patients with chronic HCV

HCV infection is associated with an increased incidence of cardiovascular (CV) events. Mechanisms underlying this association remain unknown. In our study, twenty HCV patients (median age 60.5 years, 65% male and 80% with cirrhosis) were evaluated prior, during and after direct-acting antiviral treatment. Ninety percent of patients achieved sustained virological response (SVR). Significant changes were observed in LDL particle size index, measured by LDL-C/apoB ratio, which increased after treatment (p = 0.023). In addition, HDL antioxidant capacity improved gradually from 34.4% at baseline to 42.4% at 4 weeks (p = 0.011), 65.9% at end of treatment EOT (p = 0.002) and remained elevated at 12-week (p = 0.001) after EOT compared to baseline values. Our findings suggest that a shift to a less atherogenic lipid profile may be a possible mechanism associated with CV risk reduction in patients with HCV infection achieving SVR.

Hematotoxic, oxidative and genotoxic damage in rainbow trout (Oncorhynchus mykiss) after exposure to 3-benzoylpyridine

Pyridine is a basic heterocyclic organic compound. The pyridine ring is present in many important compounds, including agricultural chemicals, medicines and vitamins. Due to their widespread industrial use, bioaccumulation and non-target toxic effects are being considered as a great risk to human and environmental health. In this study, we aimed to evaluate the hematological, oxidative and genotoxic damage potentials by different concentrations (1, 1.5, and 2 g/L) of the ketone 3-Benzoylpyridine (3BP) on rainbow trout (Oncorhynchus mykiss). Alterations in the biomarker levels of oxidative DNA damage (8-hydroxy-2'-deoxyguanosine (8-OHdG)), apoptosis (Caspase-3), malondialdehyde (MDA) as well as antioxidant enzyme activities including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), myeloperoxidase (MPO), paraoxonase (PON), and arylesterase (AR) were assessed in brain, liver, gill and blood tissues. Acetylcholinesterase (AChE) activity was also determined in brain tissue. In addition, we analyzed micronucleus (MN) rates and hematological indices of total erythrocyte count (RBC), total leukocyte count (WBC), hemoglobin (Hb), hematocrit (Hct), total platelet count (PLT), mean cell hemoglobin concentration (MCHC), mean cell hemoglobin (MCH), and mean cell volume (MCV) in blood. LC₅₀-96h value of 3BP was calculated as 5.2 g/L from the data obtained. A significant decrease in brain AChE activity was determined in clear time and dose dependent manners. While SOD, CAT, GPx, PON, and AR levels were decreased, MDA, MPO, 8-OHdG and Caspase-3 levels were increased in all tissues (p < 0.05). Again, the 3BP led to increases of MN formation at all applied concentrations in the rates of between 45.4 and 72.7%. Significant differences (p < 0.05) were found out in between all studied hematology parameters between 3BP-exposed and the control fish. In conclusion, ours study firstly indicated that the treatment doses of 3BP induced distinct hematological and oxidative alterations as well as genotoxic damage in rainbow trout.

On the Role of Paraoxonase-1 and Chemokine Ligand 2 (C-C motif) in Metabolic Alterations Linked to Inflammation and Disease. A 2021 Update

Infectious and many non-infectious diseases share common molecular mechanisms. Among them, oxidative stress and the subsequent inflammatory reaction are of particular note. Metabolic disorders induced by external agents, be they bacterial or viral pathogens, excessive calorie intake, poor-quality nutrients, or environmental factors produce an imbalance between the production of free radicals and endogenous antioxidant systems; the consequence being the oxidation of lipids, proteins, and nucleic acids. Oxidation and inflammation are closely related, and whether oxidative stress and inflammation represent the causes or consequences of cellular pathology, both produce metabolic alterations that influence the pathogenesis of the disease. In this review, we highlight two key molecules in the regulation of these processes: Paraoxonase-1 (PON1) and chemokine (C-C motif) ligand 2 (CCL2). PON1 is an enzyme bound to high-density lipoproteins. It breaks down lipid peroxides in lipoproteins and cells, participates in the protection conferred by HDL against different infectious agents, and is considered part of the innate immune system. With PON1 deficiency, CCL2 production increases, inducing migration and infiltration of immune cells in target tissues and disturbing normal metabolic function. This disruption involves pathways controlling cellular homeostasis as well as metabolically-driven chronic inflammatory states. Hence, an understanding of these relationships would help improve treatments and, as well, identify new therapeutic targets.

Antidiabetic and antioxidant activity of phlorotannins extracted from the brown seaweed Cystoseira compressa in streptozotocin-induced diabetic rats

Diabetes mellitus is considered a set of diseases that lead to high glucose level due to the absolute or relative absence of insulin. The study investigated the antioxidant activity and antidiabetic effect of phlorotannins extracted from brown seaweed Cystoseira compressa. Phlorotannins were extracted from C. compressa. It was confirmed by 2,4 dimethoxy benzaldehyde assay (DMBA), ultraviolet spectra, Fourier transform infrared spectroscopy, and ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The free radical scavenging activity of phlorotannins was estimated by total antioxidant capacity, 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity, and 2,2 azino-bis3-ethylbenthiazoline-6-sulfonic acid assays. Four groups of albino rats used in this study include control normal, control phlorotannins extract, diabetic by intraperitoneally administering of streptozotocin, and diabetic treatment with 60 mg/kg of phlorotannin extract after 4 weeks of diabetes induction. The main compound identified by UPLC-MS/MS in C. compressa extract belonged to the fuhalol. C. compressa extract showed high antioxidant properties. Phlorotannins significantly decreased serum glucose, liver malondialdehyde, and α-amylase, glucosidase activities. However, total antioxidant capacity, serum insulin, hepatic glutathione, and AMPKα2 expression in skeletal muscle were improved compared to the diabetic group. The histopathological examination showed that phlorotannins markedly reduced damage in β cells of pancreases. Phlorotannins from C. compressa have efficient antioxidant activity and the antidiabetic effect that may be utilized in human health.

High-Density Lipoproteins Are Bug Scavengers

Lipoproteins were initially defined according to their composition (lipids and proteins) and classified according to their density (from very low- to high-density lipoproteins—HDLs). Whereas their capacity to transport hydrophobic lipids in a hydrophilic environment (plasma) is not questionable, their primitive function of cholesterol transporter could be challenged. All lipoproteins are reported to bind and potentially neutralize bacterial lipopolysaccharides (LPS); this is particularly true for HDL particles. In addition, HDL levels are drastically decreased under infectious conditions such as sepsis, suggesting a potential role in the clearance of bacterial material and, particularly, LPS. Moreover, "omics" technologies have unveiled significant changes in HDL composition in different inflammatory states, ranging from acute inflammation occurring during septic shock to low-grade inflammation associated with moderate endotoxemia such as periodontal disease or obesity. In this review, we will discuss HDL modifications associated with exposure to pathogens including bacteria, viruses and parasites, with a special focus on sepsis and the potential of HDL therapy in this context. Low-grade inflammation associated with atherosclerosis, periodontitis or metabolic syndrome may also highlight the protective role of HDLs in theses pathologies by other mechanisms than the reverse transport of cholesterol.

Hepatoprotective effects of rosmarinic acid: Insight into its mechanisms of action

Liver diseases such as hepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma are one of the major health challenges in the world and many conditions such as inadequate nutrition, viral infection, ethanol and drug abuse, xenobiotic exposure, and metabolic diseases have been implicated in the development and progression of liver diseases. Several factors including lipid peroxidation, production of reactive oxygen species (ROS), peroxynitrite formation, complement factors and proinflammatory mediators, such as cytokines and chemokines, are involved in hepatic diseases. Rosmarinic acid (RA) is a natural phenolic compound found mainly in the family Lamiaceae consisting of several medicinal plants, herbs and spices. Several biological activities have been reported for RA and these include antioxidant properties as a ROS scavenger and lipid peroxidation inhibitor, anti-inflammatory, neuroprotective and antiangiogenic among others. This review is aimed at discussing the effects of RA on the liver, highlighting its hepatoprotective potential and the underlying mechanisms.

Paraoxonases and infectious diseases

The paraoxonases (PON1, PON2 and PON3) are an enzyme family with a high structural homology. All of them have lactonase activity and degrade lipid peroxides in lipoproteins and cells. As such, they play a role in protection against oxidation and inflammation. Infectious diseases are often associated with oxidative stress and an inflammatory response. Infection and inflammation trigger a cascade of reactions in the host, known as the acute-phase response. This response is associated with dramatic changes in serum proteins and lipoproteins, including a decrease in serum PON1 activity. These alterations have clinical consequences for the infected patient, including an increased risk for cardiovascular diseases, and an impaired protection against the formation of antibiotic-resistant bacterial biofilms. Several studies have investigated the value of serum PON1 measurement as a biomarker of the infection process. Low serum PON1 activities are associated with poor survival in patients with severe sepsis. In addition, preliminary studies suggest that serum PON1 concentration and/or enzyme activity may be useful as markers of acute concomitant infection in patients with an indwelling central venous catheter. Investigating the associations between paraoxonases and infectious diseases is a recent, and productive, line of research.

Serum Basal Paraoxonase 1 Activity as an Additional Liver Function Test for the Evaluation of Patients with Chronic Hepatitis

BACKGROUND

The diagnostic accuracy of currently available standard panel of liver function tests is not satisfactory for the reliable diagnosis of chronic liver disorders. Earlier studies have reported that serum basal paraoxonase 1 (PON1) activity measurement may add a significant contribution to the liver function tests.

AIM

To assess whether the measurement of serum basal paraoxonase 1 (PON1) activity would be useful as an index of liver function status in chronic hepatitis patients.

MATERIALS AND METHODS

The study included 50 chronic hepatitis patients and 50 apparently healthy controls based on inclusion & exclusion criteria. In all the subjects, standard liver function tests were analysed by using standard methods. Basal PON1 activity was estimated using spectrophotometric method by the hydrolysis of p-nitrophenylacetate. Student t-test, Pearson's correlation coefficient, diagnostic validity tests and ROC curve analysis were the methods used for the statistical analysis of the data.

RESULTS

The serum basal PON1 activity was significantly decreased in chronic hepatitis cases when compared to controls (p< 0.001). Also basal PON1 activity was positively correlated with serum total protein and albumin, and negatively correlated with serum total bilirubin, alanine amino transferase (ALT), and alkaline phosphatase (ALP) (p< 0.001) in chronic hepatitis cases but not in healthy controls. Diagnostic validity tests showed, basal PON1 activity was a better discriminator of chronic hepatitis than total protein, albumin and ALP with sensitivity of 68%, specificity of 100%, positive predictive value of 100% and negative predictive value of 75%. ROC curve analysis demonstrated highest diagnostic accuracy for ALT (AUC = 0.999) followed by PON1 (AUC = 0.990), total bilirubin (AUC = 0.977), ALP (AUC = 0.904), total protein (AUC = 0.790) and albumin (AUC = 0.595).

CONCLUSION

Diagnostic accuracy of serum PON1 activity is better than total bilirubin, total protein, albumin and ALP. PON1 activity measurement could significantly improve the current efficiency of a laboratory's evaluation of patients with suspected chronic hepatitis.

Chicory (Cichorium intybus L.) root extract regulates the oxidative status and antioxidant gene transcripts in CCl4-induced hepatotoxicity

The ability of Cichorium intybus root extract (chicory extract) to protect against carbon tetrachloride (CCl4)-induced oxidative stress and hepatotoxicity was evaluated in male rats. The rats were divided into four groups according to treatment: saline (control); chicory extract (100 mg/kg body weight daily, given orally for 2 weeks); CCl4 (1 ml/kg body weight by intraperitoneal injection for 2 consecutive days only); or chicory extract (100 mg/kg body weight daily for 2 weeks) + CCl4 injection on days 16 and 17. The levels of hepatic lipid peroxidation, antioxidants, and molecular biomarkers were estimated twenty-four hours after the last CCl4 injection. Pretreatment with chicory extract significantly reduced CCl4-induced elevation of malondialdehyde levels and nearly normalized levels of glutathione and activity of glutathione S-transferase, glutathione peroxidase (GPx), glutathione reductase, catalase (CAT), paraoxonase-1 (PON1), and arylesterase in the liver. Chicory extract also attenuated CCl4-induced downregulation of hepatic mRNA expression levels of GPx1, CAT and PON1 genes. Results of DNA fragmentation support the ability of chicory extract to ameliorate CCl4-induced liver toxicity. Taken together, our results demonstrate that chicory extract is rich in natural antioxidants and able to attenuate CCl4-induced hepatocellular injury, likely by scavenging reactive free radicals, boosting the endogenous antioxidant defense system, and overexpressing genes encoding antioxidant enzymes.

Serum paraoxonase activity, total thiols levels, and oxidative status in patients with acute brucellosis

It is well known that paraoxonase-1 (PON1) activity may decrease during the course of infection and inflammation. The aim of this study was to investigate serum PON1 activity, oxidative status, and thiols levels in patients with acute brucellosis. In addition, we investigated the PON1 phenotype in patients with acute brucellosis. Thirty patients with acute brucellosis and 35 healthy controls were enrolled. Serum paraoxonase and arylesterase activities, thiols levels, lipid hydroperoxide levels, total antioxidant capacity (TAC), total oxidant status (TOS) and oxidative stress index (OSI) were determined. Serum basal and salt-stimulated paraoxonase-arylesterase activities, TAC levels and thiols levels were significantly lower in patients with acute brucellosis than controls (for all, p < 0.05), while LOOH levels, TOS levels, and OSI values were significantly higher (for all, p < 0.05). We concluded that oxidative stress is increased, while serum PON1 activity is decreased in patients with acute brucellosis. These results indicate that lower PON1 activity is associated with oxidant-antioxidant imbalance.

Acetaminophen intoxication is associated with decreased serum paraoxonase and arylesterase activities and increased lipid hydroperoxide levels

BACKGROUND

Acetaminophen is at present one of the most commonly used analgesics and antipyretics. Recent evidence has suggested that oxidative stress is involved in the mechanism of acetaminophen intoxication. Paraoxonase-1 (PON1) plays an important role as an endogenous free-radical scavenging molecule. The aim of this study was to evaluate the influence of serum PON1 activity and oxidative stress in patients with acetaminophen intoxication.

METHODS

A total of 20 patients with acetaminophen intoxication and 25 healthy controls were enrolled. Serum total antioxidant capacity (TAC), lipid hydroperoxide (LOOH) levels, and paraoxonase and arylesterase activities were measured spectrophotometrically.

RESULTS

The serum TAC levels and the paraoxonase and arylesterase activities were significantly lower in patients with acetaminophen intoxication compared with controls (all, p < 0.001), while the serum LOOH levels were significantly higher (p < 0.001).

CONCLUSIONS

Our results suggest that decreased PON1 activity seems to be associated with increased oxidative stress in patients with acetaminophen intoxication. Measuring serum PON1 activity may be useful in assessing the development of toxicity risk in acetaminophen toxicity. It would be useful to recommend vitamins with antioxidant effects such as vitamins C and E along with medical treatments.

Serum paraoxonase and arylesterase activities and oxidative stress levels in patients with SSRI intoxication

Oxidative stress is a critical route of damage in various psychological stress-induced disorders, such as depression. Paraoxonase-1 (PON1) plays an important role as an endogenous free-radical scavenging molecule. The aim of this study was to evaluate the influence of serum PON1 activity and oxidative stress in patients with selective serotonin reuptake inhibitor (SSRI) intoxication. A total of 11 patients with SSRI intoxication and 20 healthy controls were enrolled. The serum total antioxidant capacity (TAC) and malondialdehyde (MDA) levels, as well as the paraoxonase and arylesterase activities, were measured spectrophotometrically. The serum TAC levels and the paraoxonase and arylesterase activities were significantly lower (for all, p < 0.001), whereas the serum MDA levels were significantly higher in the patients with SSRI intoxication than in the controls (p < 0.001). These results indicated that decreased PON1 activity and increased oxidative stress represent alternative mechanisms in SSRI toxicity. More studies are needed to elucidate the role of PON1 activity in the etiology of SSRI intoxication.

Effects of paraoxon on serum biochemical parameters and oxidative stress induction in various tissues of Wistar and Norway rats

This study investigates the effects of different doses of paroxon (POX), an active metabolite of the organophosphate pesticide parathion, on some serum biochemical parameters and induction of oxidative stress in various tissues of female Wistar and Norway rats. The rats were intraperitoneally treated with 0.3, 0.7, 1 and 1.5 mg/kg of POX. The parameters were evaluated after 24h. The results showed that the decreased glutathione level and catalase, glutathione-S-transferase and lactate dehydrogenase activities in tissues of Wistar rat were higher than Norway rat at higher doses of POX. At these concentrations, POX increased superoxide dismutase activity, malondialdehyde level and some serum biochemical indices. In conclusion, POX induces the production of free radicals and oxidative stress in a dose-dependent manner. Induction of oxidative stress in POX-treated rats is in the order of brain > liver > heart > kidney>spleen. Wistar rat is found to be more sensitive to the toxicity of POX compared to Norway rat.

Oxidative stress and liver disease

In humans, oxidative stress and antioxidant defenses are the sum of a complicated network of enzymatic and non-enzymatic processes. Depending on the stage and severity of diseases, a patient's antioxidant armamentarium may increase as an appropriate response to an oxidant challenge, whereas others may decrease as an indication of unbalanced consumption. In some cases, the formation of reactive oxygen species is a requisite and healthy event. In fact, free radicals can affect intracellular signal transduction and gene regulation, resulting in cytokine production essential to the inflammatory process. In many other cases, especially liver diseases, excessive oxidative stress undoubtedly contributes to the progression and pathological findings of disease and serves as a prognostic indicator. Reactive oxygen species are highly reactive molecules that are naturally generated in small amounts through metabolism and could damage cellular molecules such as lipids, proteins or DNA. Oxidative stress plays a major role in many liver diseases. In this review, we summarize the biological character of free radicals and some antioxidants, and the related methods of analysis. Then, we discusses the association of oxidative stress to many types of liver diseases.

Modulation of paraoxonases during infectious diseases and its potential impact on atherosclerosis

The paraoxonase (PON) gene family includes three members, PON1, PON2 and PON3, aligned in tandem on chromosome 7 in humans and on chromosome 6 in mice. All PON proteins share considerable structural homology and have the capacity to protect cells from oxidative stress; therefore, they have been implicated in the pathogenesis of several inflammatory diseases, particularly atherosclerosis. The major goal of this review is to highlight the modulation of each of the PONs by infective (bacterial, viral and parasitic) agents, which may shed a light on the interaction between infectious diseases and PONs activities in order to effectively reduce the risk of developing atherosclerosis.

Serum paraoxonase and arylesterase activities in various forms of hepatitis B virus infection

The aim of this study was to determine and evaluate the activity of paraoxonase and arylesterase enzymes in various clinical forms of hepatitis B infection and to investigate the correlation between these parameters and chronic disease course/fibrosis. Overall, 40 patients diagnosed as hepatitis B carriers (CIHBV), 40 chronic active hepatitis B (CAHBV) patients, and 40 healthy adults (control group) between 18 and 65 years of age were enrolled the study. Serum paraoxonase and arylesterase activities were measured spectrophotometrically. Their activities were significantly lower in patients with CAHBV compared with CIHBV patients or with control group patients (P<0.001). There was a negative correlation between alanine aminotransferase levels and the activity of paraoxonase and arylesterase (r = -0.38, P = 0.001 and r = -0.28, P = 0.002, respectively). A statistically significant negative correlation was found between arylesterase activity in the sera of CAHBV patients and HBV DNA levels (ρ = -0.33, P = 0.03). On the contrary, no correlation was found between paraoxonase levels and HBV DNA levels (P>0.05). The histology activity index of CAHBV patients did not correlate with paraoxonase and arylesterase activities (P>0.05). In light of these findings, it may be assumed that during the progression of an inactive hepatitis B carrier to being actively infected, reduced paraoxonase and arylesterase activities may be observed.

The assessment of carotid intima media thickness and serum paraoxonase-1 activity in Helicobacter pylori positive subjects

Background

The role of inflammation in the pathogenesis and progression of atherosclerosis has been increasingly discussed. Although the seroepidemiological studies have suggested a relationship between Helicobacter pylori (H. pylori) infection and atherosclerosis; the issue is still controversial. It is well known that abnormal lipid profil is related to atherosclerosis and the measurement of carotid-intima media thickness (CIMT) is one of the surrogate marker of atherosclerosis. The serum concentration of high-density lipoprotein (HDL-C) has been known to have an inverse correlation with the development of atherosclerosis. Paraoxonase-1 (PON1) is a major anti-atherosclerotic component of HDL-C. PON1 activity is related to lipid peroxidation and prospective cardiovascular risk. The aim of this study was to investigate CIMT and serum PON1 activities along with lipid parameters in H. pylori positive and negative subjects.

Methods

Thirty H. pylori positive subjects and thirty-one negative subjects were enrolled. H. pylori infection was diagnosed by the presence of positivity of stool H. pylori antigen test or Carbon 14 labeled urea breath test. Serum PON1 activity was measured spectrophotometrically. Traditional cardiovascular risk factors were investigated and laboratory analysis included measurement of serum triglycerides (TG), total cholesterol (TC), high-density lipoprotein (HDL-C) and low-density lipoprotein cholesterol (LDL-C). We assessed CIMT by high-resolution ultrasound of both common carotid arteries.

Results

We found that the mean and maximum values of right and overall CIMT in H. pylori positive subjects were significantly thicker than those of H. pylori negative subjects. There was no significant differences in serum HDL-C, LDL-C, TC levels and TC/HDL-C ratios between two groups. Serum TG levels of H. pylori positive subjects were significantly higher than those of H. pylori negative subjects (p = 0.014). We found that PON1 activities were significantly lower in H. pylori positive subjects compared with negative subjects. No significantly correlation was observed between PON1 and CIMT values.

Conclusions

There is an increase in CIMT values in patients with H. pylori positive compared to H. pylori negative subjects. PON1 activity decrease significantly in H. pylori positive subjects. However, an association between PON1 and CIMT was not found. These data indicated that H. pylori may have a role in atherosclerotic processes, however, further studies are needed to evaluate the exact mechanisms.