Serum paraoxonase 1 activity status in patients with liver disorders

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.

The Relationship between Cancer and Paraoxonase 1

Extensive research has been carried out to understand and elucidate the mechanisms of paraoxonase 1 (PON1) in the development of diseases including cancer, cardiovascular diseases, neurological diseases, and inflammatory diseases. This review focuses on the relationship between PON1 and cancer. The data suggest that PON1, oxidative stress, chronic inflammation, and cancer are closely linked. Certainly, the gene expression of PON1 will remain challenging to study. Therefore, targeting PON1, redox-sensitive pathways, and transcription factors promise prevention and therapy in the development of several diseases, including cancer.

The Activity and Polymorphism of the PON1 in Patients with Chronic Liver Disease: a Systematic Review and Meta-analysis

BACKGROUND

Liver diseases are among the ten deadliest diseases in the world. Measuring PON1 is a test to assess the degree of liver disorder. There are several preliminary studies on the rate of PON1 activity in people with liver disease, and there are differences between the results of these studies; therefore, the aim of this research work is to determine the level of PON1 activity in people with liver disease using meta-analysis.

METHOD

The study searched to select articles that were published electronically from 2002 to 2020, in national and international databases of SID, MagIran, Embase, ScienceDirect, Scopus, PubMed, and Web of Science (WoS).

RESULTS

Among the articles included in the meta-analysis, the samples in the case (patients) and control groups were 807 and 2276, respectively. The mean activity of PON1 in individuals with liver disease in the case and control groups were 142.06 ± 7.7 and 272.19 ± 39.6, respectively, and this was statistically significant (P < 0.05). The mean difference analysis highlights a difference of - 2.75 ± 0.48 between the patient and control groups, indicating that liver disease significantly reduces PON1 activity.

CONCLUSION

The results of this study demonstrate that the polynomorphism of the PON1 is associated with an increased risk of liver disease, with lower levels of PON1 activity in people with liver disease than in healthy patients and this decrease was more in patients with liver cirrhosis than in other liver diseases. Given the importance of this gene's activity, studies such as this could provide a promising path for better drug design and treatment in future.

Hepatoprotective effect of the hydroalcoholic extract of Cichorium intybus in a rat model of obstructive cholestasis

BACKGROUND AND STUDY AIMS

Obstructive cholestasis increases the levels of oxidants and inflammatory mediators, leading to liver damage. Previous studies have found that Cichorium intybus possesses anti-inflammatory effects. In the present study, the effects of the hydroalcoholic extract of C. intybus leaves were assessed in a rat model of obstructive cholestasis.

MATERIAL AND METHODS

Male Wistar rats were randomly divided into five groups (n = 6 rats per group): sham-operated, control [bile duct ligation (BDL) + vehicle)] and BDL + extract treatment (100, 200 and 400 mg/kg/day, i.p.) groups. Rats received treatments for 7 consecutive days. On the eighth day, prothrombin time (PT); serum albumin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase and total and direct bilirubin levels and total antioxidant and paraoxonase activities were measured using colorimetric methods. In addition, tumour necrosis factor-α and nitric oxide (NO) levels were measured using enzyme-linked immunosorbent assay.

RESULTS

The hydroalcoholic extract of C. intybus significantly decreased PT and the serum levels of AST, ALT, TNF-α and NO compared with the control group (p < 0.05). On the other hand, the serum albumin levels were increased in the extract-treated groups compared with the control group (p < 0.05).

CONCLUSION

The hydroalcoholic extract of C. intybus protects the liver against injury induced by obstructive cholestasis.

The Structure and Function of Paraoxonase-1 and Its Comparison to Paraoxonase-2 and -3

Serum paraoxonase-1 (PON1) is the most studied member of the group of paraoxonases (PONs). This enzyme possesses three enzymatic activities: lactonase, arylesterase, and paraoxonase activity. PON1 and its isoforms play an important role in drug metabolism as well as in the prevention of cardiovascular and neurodegenerative diseases. Although all three members of the PON family have the same origin and very similar amino acid sequences, they have different functions and are found in different locations. PONs exhibit substrate promiscuity, and their true physiological substrates are still not known. However, possible substrates include homocysteine thiolactone, an analogue of natural quorum-sensing molecules, and the recently discovered derivatives of arachidonic acid—bioactive δ-lactones. Directed evolution, site-directed mutagenesis, and kinetic studies provide comprehensive insights into the active site and catalytic mechanism of PON1. However, there is still a whole world of mystery waiting to be discovered, which would elucidate the substrate promiscuity of a group of enzymes that are so similar in their evolution and sequence yet so distinct in their function.

Association of PON1 gene polymorphisms and enzymatic activity with risk of coronary artery disease

Background: The present case-control study evaluated the association of PON1 gene polymorphisms and enzyme activity in the western Indian population. Materials & methods: Angiographically proven coronary artery disease (CAD) formed the cases. PON1 polymorphisms (Q192R, L55M) and enzymatic activity (paraoxonase) were assessed. Results: A total of 502 participants (251 per group) were studied. PON1 Q192R and L55M polymorphisms were not associated with the risk of CAD. Notably, a weak association was observed between Q192R polymorphisms and the risk of CAD. CAD patients had significantly lower PON1 enzymatic activity (U/L) as compared with the controls regardless of the genotype. Conclusion: Low serum PON1 activity was confirmed to be an independent predictor for the risk of CAD.

Paraoxonase-1 Serum Concentration and PON1 Gene Polymorphisms: Relationship with Non-Alcoholic Fatty Liver Disease

Background: Non-alcoholic fatty liver disease (NAFLD) is an important cause of chronic liver diseases around the world. Paraoxonase-1 (PON1) is an enzyme produced by the liver with an important antioxidant role. The aim of this study was to evaluate PON1 serum concentration and PON1 gene polymorphisms in patients with NAFLD. Materials and methods: We studied a group of 81 patients with NAFLD with persistently elevated aminotransferases and a control group of 81 patients without liver diseases. We collected clinical information and performed routine blood tests. We also measured the serum concentration of PON1 and evaluated the PON1 gene polymorphisms L55M, Q192R, and C-108T. Results: There was a significant difference (p < 0.001) in serum PON1 concentrations among the two groups. The heterozygous and the mutated homozygous variants (LM + MM) of the L55M polymorphism were more frequent in the NAFLD group (p < 0.001). These genotypes were found in a multivariate binary logistic regression to be independently linked to NAFLD (Odds ratio = 3.4; p = 0.04). In a multivariate linear regression model, the presence of NAFLD was associated with low PON1 concentration (p < 0.001). Conclusions: PON1 serum concentrations were diminished in patients with NAFLD, and the presence of NAFLD was linked with low PON1 concentration. The LM + MM genotypes of the PON1 L55M polymorphism were an independent predictor for NAFLD with persistently elevated aminotransferases.

Serum choline and butyrylcholinesterase changes in response to endotoxin in calves receiving intravenous choline administration

Endotoxemia treatment options are still of interest due to high mortality and choline treatment is one of them because of its role in the cholinergic anti-inflammatory pathway. This study investigated serum choline and butyrylcholinesterase (BChE) responses, and their correlations with inflammatory, oxidative stress and tissue damage biomarkers, including paraoxanase-1 (PON1), and clinical signs in calves with endotoxemia and the effect of choline treatment in these responses. Healthy calves (n = 20) were divided equally into 4 groups: Control (0.9% NaCl, iv), Choline (C; 1 mg/kg/iv,once), Lipopolysaccharide (LPS; 2 μg/kg/iv,once) and LPS + C. Clinical and laboratory examinations were performed before and 0.5-48 h (hrs) after treatments. Following LPS administration, serum choline level increased at 0.5-24 h (P < .01), whereas serum BChE and PON1 level decreased at 48 h (P < .01) compared to their baselines. In LPS + C group, the increase in serum choline level was significantly higher (P < .01) than that of C and LPS groups. LPS did not decrease serum BChE levels significantly in calves treated with choline. Serum choline and BChE results correlated negatively with white blood cell count and positively (P < .001) with PON1 levels, oxidative stress index, inflammation and hepato-muscular injury markers. In conclusion serum choline and BChE may have a role in the pathophysiology of endotoxemia in calves. High serum choline concentration is associated with an improvement in response to LPS administration in calves treated with choline, probably by preventing the imbalances between oxidative stress and anti-oxidant capacity, preventing the serum BChE and PON1 decreases, and inhibition/attenuation of acute phase reaction and hepato-muscular injury in calves with endotoxemia.

Alterations in serum paraoxonase-1 activity and lipid profile in chronic alcoholic patients infected with Strongyloides stercoralis

The objective of this study was to investigate paraoxonase-1 (PON1) activity, cortisol levels, and the lipid profile in the sera of alcoholic and non-alcoholic Strongyloides stercoralis-infected and uninfected individuals in a sample of 276 individuals attended at the National Health System in Salvador, Bahia, Brazil. The activity of PON1 was measured by the Beltowski method, serum lipids, and cortisol levels using commercial kits. PON1 activity was low in both alcoholic and non-alcoholic individuals infected with S. stercoralis. A positive correlation was observed between PON1 activity and cortisol concentration in alcoholic individuals who were not infected with S. stercoralis; whereas a negative correlation occurred in S. stercoralis-infected nonalcoholic individuals. The levels of triglycerides, LDL-C, and VLDL-C in S. stercoralis-infected alcoholic individuals were significantly lower than in uninfected alcoholic individuals. The high level of HDL-C and the low level of LDL-C, VLDL, triglycerides and PON1 activity in alcoholic patients infected with S. stercoralis evidenced an anti-atherogenic pattern.

Açai (Euterpe oleracea Mart.) Upregulates Paraoxonase 1 Gene Expression and Activity with Concomitant Reduction of Hepatic Steatosis in High-Fat Diet-Fed Rats

Açai (Euterpe oleracea Mart.), a fruit from the Amazon region, has emerged as a promising source of polyphenols. Açai consumption has been increasing owing to ascribed health benefits and antioxidant properties; however, its effects on hepatic injury are limited. In this study, we evaluated the antioxidant effect of filtered açai pulp on the expression of paraoxonase (PON) isoforms and PON1 activity in rats with nonalcoholic fatty liver disease (NAFLD). The rats were fed a standard AIN-93M (control) diet or a high-fat (HF) diet containing 25% soy oil and 1% cholesterol with or without açai pulp (2 g/day) for 6 weeks. Our results show that açai pulp prevented low-density lipoprotein (LDL) oxidation, increased serum and hepatic PON1 activity, and upregulated the expression of PON1 and ApoA-I in the liver. In HF diet-fed rats, treatment with açai pulp attenuated liver damage, reducing fat infiltration and triglyceride (TG) content. In rats receiving açai, increased serum PON1 activity was correlated with a reduction in hepatic steatosis and hepatic injury. These findings suggest the use of açai as a potential therapy for liver injuries, supporting the idea that dietary antioxidants are a promising approach to enhance the defensive systems against oxidative stress.

Total antioxidant and total oxidant states, and serum paraoxonase-1 in neonatal sepsis

BACKGROUND

Paraoxonase-1 (PON-1) is an enzyme with a glycoprotein structure that depends on calcium and which is located in serum high-density lipoprotein (HDL). The aim of this study was to evaluate PON-1, and oxidant/antioxidant state, before and after treatment for neonatal sepsis, and to determine the usability of PON-1 in neonatal sepsis treatment.

METHODS

A total of 35 neonatal sepsis patients and 35 healthy controls were included in the study. Activity of PON-1, total oxidant state (TOS) and total antioxidant state (TAS) were measured and oxidative stress index (OSI) was calculated.

RESULTS

In the neonatal sepsis patients, pre-treatment TAS, TOS and OSI were significantly higher than the post-treatment levels (P < 0.0001, P < 0.0001 and P < 0.0001, respectively), and PON-1 was significantly lower (P < 0.0001). Similarly, pre-treatment TAS, TOS and OSI in the sepsis group were also significantly higher than in the control group (P < 0.0001, P < 0.0001 and P < 0.0001, respectively) and PON-1 was significantly lower (P < 0.0001). Post-treatment TAS in the sepsis group was significantly higher than in the control group (P = 0.009), whereas post-treatment TOS, OSI and PON-1 in the sepsis group were not significantly different to the control group (P = 0.078, P = 0.597 and P = 0.086, respectively).

CONCLUSION

Low serum PON-1 was found in neonatal sepsis. Serum PON-1 is thought to be a useful biomarker to evaluate the effectiveness of treatment and recovery in neonatal sepsis.

Inflammatory and oxidative biomarkers of disease severity in dogs with parvoviral enteritis

OBJECTIVES

To study changes in serum C-reactive protein, haptoglobin, ceruloplasmin and albumin concentration, total anti-oxidant capacity and paraoxonase-1 and butyrylcholinesterase activity in dogs with parvoviral enteritis of different degrees of clinical severity.

METHODS

Prospective study of 9 healthy and 43 dogs with parvoviral enteritis that were classified into mildly, moderately and affected groups.

RESULTS

Dogs with parvoviral enteritis had a significant increase in C-reactive protein compared with healthy dogs, with an increase of higher magnitude in animals with more severe clinical signs. All dogs with parvoviral enteritis had a significant increase in haptoglobin concentration compared with healthy dogs, but with no difference according to disease severity. There was a decrease in paraoxonase-1 activity in parvoviral enteritis.

CLINICAL SIGNIFICANCE

Major increases of C-reactive protein concentrations in dogs with parvoviral enteritis are a marker of disease severity. In addition, higher values for anti-oxidants in severe cases compared with mild and moderate cases suggest a possible compensatory anti-oxidant mechanism.

Serum lactonase and arylesterase activities in alcoholic hepatitis and hepatitis B

BACKGROUND

PON1 is an HDL-associated enzyme having antioxidant activity. PON1 is synthesized in the liver, and there is decreased synthesis of PON1 with increased lipid peroxidation. The study was carried with the aim of establishing whether chronic liver disease (CLD) produced any significant changes in serum arylesterase (AE) and lactonase activities of PON. The second objective was to determine whether there was any correlation between serum AE and lactonase activities and the various routine liver function tests. The usefulness of adding serum lactonase and AE activity to standard liver function tests was analyzed by multiple logistic regression analysis. Finally, the diagnostic efficacy or analytical performance of AE and lactonase in assessing patients with CLD was determined using 'receiver operating characteristic' (ROC) plot.

METHODS

The study group consisted of 120 subjects; 60 were patients with liver disease out of which 40 were having chronic alcoholic liver disease and 20, acute viral hepatitis B, and 60 were healthy controls. Serum PON1 lactonase activity was measured manually using dihydrocoumarin, and AE activity was measured using phenylacetate as substrate. Liver function tests (bilirubin, albumin, AST, ALT, alkaline phosphatise) were done by standard technique.

RESULT

The serum lactonase and AE activities were decreased significantly in patients with chronic alcoholic liver disease (p < 0.001, p < 0.001) and acute viral hepatitis B (p < 0.001, p < 0.001). Both measurements showed higher efficiency in testing liver dysfunction in multivariate regression analysis. Model 1 consisted of bilirubin, albumin, AST, ALT, and alkaline phosphatase, R2 = 0.912. Model 2 consisted of model 1+arylesterase having higher R2 = 0.0.954, and model 3 consisted of model 1+lactonase having R2 = 0.962. ROC plots demonstrated a high diagnostic accuracy for serum PON1 lactonase (area under ROC curve = 0.982) and serum PON1 arylesterase (area under ROC curve = 0.986).

CONCLUSION

Low PON1 lactonase and AE activity were found in acute viral hepatitis B and in chronic alcoholic hepatitis.

Quantitative proteomic analysis identified paraoxonase 1 as a novel serum biomarker for microvascular invasion in hepatocellular carcinoma

This study aimed to identify serum biomarkers for microvascular invasion (MVI) in hepatocellular carcinoma (HCC). MVI is a histological sign of micrometastasis in the liver and is considered as one of the most powerful prognostic factors in HCC. The serum of HCC patients with different vascular invasion statuses was examined by iTRAQ-based proteomic profiling. The expression levels of 24 proteins were associated with the extent of vascular invasion in the pooled samples of 45 HCC cases. Western blot analyses in 90 HCC cases confirmed the correlation of the expression level of paraoxonase 1 (PON1) with the extent of vascular invasion. ELISA assays demonstrated the diagnostic utility of the PON1 level, with the area under curve values of 0.847 and 0.889 for the MVI and gross vascular invasion, respectively, relative to the patients without vascular invasion, in a cohort of 387 additional HCC cases. Immunohistochemistry revealed that PON1 expression in tumor cells was inversely correlated with the extent of vascular invasion in 200 additional HCC cases. In conclusion, using a proteomic approach, we found that serum PON1 was a novel diagnostic biomarker for MVI. The prognostic values of serum PON1 and its possible therapeutic applications are worth further investigation.

Serum paraoxonase levels in patients with acute liver disease

Paraoxonase is an anti-oxidant enzyme, which circulates in the plasma, tightly bound to HDL. This enzyme is known to be synthesized in the liver. This study was carried out in order to ascertain the diagnostic utility of this enzyme in acute liver disease. Serum basal as well as salt (NaCl) stimulated paraoxonase was estimated in 50 patients with an established diagnosis of acute liver disease and also in 50 healthy blood donors. Paraoxonase levels were significantly lower in patients as compared with controls (P < 0.05). The 'receiver operating characteristic' plot showed that this enzyme has a high degree of sensitivity and specificity for the diagnosis acute liver disease. Serum PON is likely to emerge as an additional test of liver function, as it encompasses three different attributes of hepatic function namely, synthetic capacity, detoxication and secretory functions.

The three-gene paraoxonase family: physiologic roles, actions and regulation

The paraoxonase (PON) gene family is composed of three members (PON1, PON2, PON3) that share considerable structural homology and are located adjacently on chromosome 7 in humans. By far the most-studied member is PON1, a high-density lipoprotein-associated esterase/lactonase, also endowed with the capacity to hydrolyze organophosphates, but all the three proteins prevent oxidative stress and fight inflammation. They therefore seem central to a wide variety of human illnesses, including atherosclerosis, diabetes mellitus, mental disorders and inflammatory bowel disease. The major goal of this review is to highlight the regulation of each of the paraoxonase components by diverse nutritional molecules and pharmacological agents as well as a number of pathophysiological events, such as oxidative stress and inflammation. Considerable and detailed cell-based studies and animal model experiments have been provided to allow a thorough scrutiny of PON modulation, which will increase our understanding and ability to target these genes in order to efficiently increase their transcriptional activity and decrease the risks of developing different disorders.