Arylesterase Activity Research Articles

Gastroprotective effects of bromelain on indomethacin-induced gastric ulcer in rats

Gastric ulcer is one of the most common diseases of the gastrointestinal system and some of its complications are the main causes of morbidity and mortality. Bromelain (BRM), a sulfhydryl proteolytic enzyme, has multiple activities in many areas of medicine as an antioxidant and anti-inflammatory agent. In this study, it was aimed to investigate the anti-inflammatory and oxidative stress-mediated therapeutic effect of BRM in a gastric ulcer model induced by indomethacin (IND) which is a non-steroidal anti-inflammatory drug (NSAID) with gastric ulcer-forming effects. Gastric mucosal paraoxonase (PON), arylesterase (ARE), catalase (CAT), myeloperoxidase (MPO) and glutathione peroxidase (GPx) activity and total glutathione (GSH) levels were analyzed. Interleukin-33 (IL-33), the nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) levels were determined by immunohistochemically. Although IND-induced histopathological changes occurred, BRM pretreatment prevented these effects. As a result of the study, it was determined that BRM had an anti-ulcerative effect at a dose of 50 mg/kg. BRM given at this dose significantly decreased gastric tissue MPO activity, and increased CAT, PON, ARE, GPx activity and GSH level. The increased IL-33 and decreased Nrf-2 and HO-1 levels were obtained in IND group and these changes were reversed by BRM. As a result, it was concluded that BRM may have protective effects in IND-induced gastric model by reducing inflammation and regulating oxidant/antioxidant balance.

Hepatoprotective Effect of Eulophia gracilis on Benzene-Induced Liver Toxicity in Wistar Rats

Benzene (BZ) is an organic solvent that can induce pathological disorders such as haematological disburbance and liver damage. Eulophia gracilis (EG) plant is a medicinal orchid explored traditionally to treat myriads of ailments including anemia and liver disease. The present study investigated the protective effect of Eulophia gracilis extract against Benzene-induced hepatotoxicity in haematologically disturbed rats. Male Wistar rats (110-120 g) were randomized into four groups (n = 6 / group): I (control), II BZ-treated: 175 mg/kgbw benzene every alternate days for two weeks; III Co-treated with 175 mg/kgbw benzene and E. gracilis 200 mg/kgbw each day for two weeks and IV administered 200 mg/kg of E. gracilis for two weeks. BZ caused a significant reduction in PCV, Hb, RBC and altered white blood cell count. Similarly, activities of hepatic biomarker enzymes such as alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, and γ-glutamyl transferase were significantly increased in the BZ-treated group relative to control. Furthermore, BZ caused a significant decrease in the activities of hepatic arylesterase, superoxide dismutase, catalase and glutathione-S-transferase and levels of Ascorbic Acid (AA) and Glutathione (GSH). A significant increase in hepatic malondialdehyde content, altered liver ultrastructure and modulation of p53 and BCl-2 protein in the liver also accompanied benzene intoxication. However, coadministration of E. gracilis ameliorated the BZ-induced changes in haematological parameter and liver biomarkers and improved hepatic antioxidant biomarkers and ultrastructure. Overall, the results suggest that Eulophia gracilis protected against BZ-induced hepatic oxidative damage and haematological disturbance in rats.

The usefulness of arylesterase in predicting contrast-induced nephropathy in ST-segment elevation myocardial infarction patients undergoing percutaneous coronary intervention

Aim: Oxidative stress is one of the causes of contrast-induced nephropathy (CIN). Paraoxonase1 (PON1), is one of the oxidative stress markers. The most sensitive method that has been in use to measure PON1 enzyme activity is the measurement of arylesterase (AREase) activity. To explore relationship between AREase activity and CIN development.
 Material and Method: A total of 58 STEMI patients were included in our study. The patients were divided into two groups as CIN (+) and CIN (-). The success of AREase activity level in predicting the development of CIN was also examined by using ROC analysis.
 Results: Out of the study patients, 13 were CIN (+) and 45 were CIN (-). AREase activity was found to be statistically significantly lower in the CIN (+) group (875 U/L vs 819 U/L, p= 0.004). In the regression analysis, diabetes mellitus, contrast volume and AREase activity were determined as independent risk factors in the development of CIN. As a result of the ROC analysis, we concluded that the AREase activity level

Advanced oxidation protein products levels and Paraoxonase 1(Arylesterase) activity in patients with thyrodisim

Objectives: The purpose of study was to explore the correlation of advanced oxidation protein products (AOPP), which reflect the oxidation of protein and the oxidative stress status, and the activity of antioxidant enzyme of Paraoxonase (PON1), using its arylesterase activity in patients with thyrodisim.
 Methods: The study included 100 women with newly diagnosed thyrodisim were subdivided in two groups according to thyroid hormones levels: hyperthyroidism group (50 female patients, age range 18-60 years); and hypothyroidism group (50 female patients, age range 18-75 years). A control group (30 healthy females, age range 18–70 years) was also included for comparison. Demographic and clinical measurements for all participants were recorded which include: Body mass index (BMI), age, weight, height, lipid profile, vitamin D, thyroid hormones (TSH, T3, and T4, FT3, FT4), AOPP levels, and arylesterase activity.
 Results: The serum level of AOPP in hypothyroidism group (71.92±19.04 μmol/L) and in hyperthyroidism group (30.41±4.72 μmol/L) were significantly higher than controls (13.12±2.50 μmol/L) (P<0.05). In contrast, lower aryl esterase activity was found in hypothyroidism (5.03±0.50 U/L), and hyperthyroidism (3.64±0.40 U/L) when compared to control group (6.78±0.62 Ku/L) with significant values (P< 0.05).
 Conclusions: these results disclosed a significant role of protein oxidation in patients with hypothyroidism as well as the oxidative stress status.

Paraoxonase 1 and Chronic Kidney Disease: A Meta-Analysis.

Oxidative stress is known to be associated with the pathophysiology of chronic kidney disease (CKD). Paraoxonase 1 (PON1) is an antioxidant enzyme that has been proposed as a biomarker for CKD. While several studies have reported an association between serum PON1 activity and CKD, consensus based on systematically analyzed data remains necessary. We set out to conduct a meta-analysis of literature on PON1 in CKD. Electronic databases, such as MEDLINE, Embase and CENTRAL, were searched for available studies on PON1 activity in patients with CKD (without dialysis) as published before December 2022. A random-effects meta-analysis was performed. In total, 24 studies (22 studies on paraoxonase and 11 on arylesterase activity) were eligibly identified. Patients with CKD showed a lower activity of paraoxonase (standard mean difference [SMD], -1.72; 95% confidence interval [CI], -2.15 to -1.29) and arylesterase (SMD, -2.60; 95%CI, -3.96 to -1.24) than healthy controls. In the subgroup analyses, paraoxonase activity was lower in chronic kidney failure (CKF), an advanced stage of CKD, than in non-CKF. In summary, PON1 activity is low in patients with CKD, suggesting that the antioxidant defense by PON1 is impaired in CKD. The decrease in enzyme activity is pronounced in advanced CKD showing some variability depending on the substrate employed to measure PON1 activity. Further studies are warranted.

Highly Dynamic Gene Family Evolution Suggests Changing Roles for PON Genes Within Metazoa.

Change in gene family size has been shown to facilitate adaptation to different selective pressures. This includes gene duplication to increase dosage or diversification of enzymatic substrates and gene deletion due to relaxed selection. We recently found that the PON1 gene, an enzyme with arylesterase and lactonase activity, was lost repeatedly in different aquatic mammalian lineages, suggesting that the PON gene family is responsive to environmental change. We further investigated if these fluctuations in gene family size were restricted to mammals and approximately when this gene family was expanded within mammals. Using 112 metazoan protein models, we explored the evolutionary history of the PON family to characterize the dynamic evolution of this gene family. We found that there have been multiple, independent expansion events in tardigrades, cephalochordates, and echinoderms. In addition, there have been partial gene loss events in monotremes and sea cucumbers and what appears to be complete loss in arthropods, urochordates, platyhelminths, ctenophores, and placozoans. In addition, we show the mammalian expansion to three PON paralogs occurred in the ancestor of all mammals after the divergence of sauropsida but before the divergence of monotremes from therians. We also provide evidence of a novel PON expansion within the brushtail possum. In the face of repeated expansions and deletions in the context of changing environments, we suggest a range of selective pressures, including pathogen infection and mitigation of oxidative damage, are likely influencing the diversification of this dynamic gene family across metazoa.

Oxidized LDL and Risk of Coronary Heart Disease

Oxidized LDL cholesterol (ox-LDL) is considered to be a key factor of initiating and accelerating coronary heart disease CHD and diabetes Mellitus DM , is associated with several mechanisms one of them Oxidative stress. The aim of this study was to find the association between ox- LDL ,HDL-C , TG , LDL-C and arylesterase , with CHD risk in different age groups in males and females , the difference in these risk factors can explain the sex difference and how much the changes in the risk factors levels in CHD and CHD with DM patients between age groups.
 Methods: determination biochemical parameters of serum blood of ox-LDL , TG , TC , HDL-c , LDL-c , S. Glucose and arylesterase activity were measured in cases male and females were carried CHD and CHD with DM .The cases divided in different the age groups (40-49) , (50-59) and (60-69) years and compered the result with control groups .
 Results: mean Value of ox-LDL and oxidation ratio of LDL show significantly higher at (p<0.05) in CHD and (p<0.001) in CHD with DM patient for females in the age group (40-49) years but in the males show the results significant decrease and different significant in others groups ,beside to effect Sex and age some the studied biochemistry parameters levels and signification decrease in HDL-C and arylesterase levels as antioxidant enzymes in females and male patient selected compared with control groups.

Associations between Endothelial Lipase, High-Density Lipoprotein, and Endothelial Function Differ in Healthy Volunteers and Metabolic Syndrome Patients.

Metabolic syndrome (MS) is characterized by endothelial- and high-density lipoprotein (HDL) dysfunction and increased endothelial lipase (EL) serum levels. We examined the associations between EL serum levels, HDL (serum levels, lipid content, and function), and endothelial function in healthy volunteers (HV) and MS patients. Flow-mediated dilation (FMD), nitroglycerin-mediated dilation (NMD), serum levels of HDL subclasses (measured by nuclear magnetic resonance (NMR) spectroscopy), and EL serum levels differed significantly between HV and MS patients. The serum levels of triglycerides in large HDL particles were significantly positively correlated with FMD and NMD in HV, but not in MS patients. Cholesterol (C) and phospholipid (PL) contents of large HDL particles, calculated as HDL1-C/HDL1-apoA-I and HDL1-PL/HDL1-apoA-I, respectively, were significantly negatively correlated with FMD in HV, but not in MS patients. Cholesterol efflux capacity and arylesterase activity of HDL, as well as EL, were correlated with neither FMD nor NMD. EL was significantly negatively correlated with HDL-PL/HDL-apoA-I in HV, but not in MS patients, and with serum levels of small dense HDL containing apolipoprotein A-II in MS patients, but not in HV. We conclude that MS modulates the association between HDL and endothelial function, as well as between EL and HDL. HDL cholesterol efflux capacity and arylesterase activity, as well as EL serum levels, are not associated with endothelial function in HV or MS patients.

HDL cholesterol efflux capacity and phospholipid content are associated with the severity of acute ischemic stroke and predict its outcome

Background/AimsImpaired high-density lipoprotein (HDL) function and composition are more strongly related to cardiovascular morbidity than HDL concentration. However, it is unclear whether HDL function and composition predict ischemic stroke severity and outcome. We aimed to evaluate these associations. MethodsWe prospectively studied 199 consecutive patients who were admitted with acute ischemic stroke. The severity of stroke was evaluated at admission with the National Institutes of Health Stroke Scale (NIHSS). Severe stroke was defined as NIHSS ≥ 5. The outcome was assessed with dependency at discharge (modified Rankin scale 2–5) and in-hospital mortality. Cholesterol efflux capacity (CEC), phospholipid levels, lecithin:cholesterol acyl transferase (LCAT)-phospholipase activity, paraoxonase-1 (PON1)-arylesterase activity and serum amyloid A1 (SAA1) content of HDL were measured. ResultsCEC, phospholipid levels and LCAT-phospholipase activity of HDL were lower and SAA1 content of HDL was higher in patients with severe stroke. Patients who were dependent at discharge had lower CEC, PON1-arylesterase activity, phospholipid content and LCAT-phospholipase activity of HDL and higher HDL-SAA1 content. Independent predictors of dependency at discharge were the NIHSS at admission (RR 2.60, 95% CI 1.39–4.87), lipid-lowering treatment (RR 0.17, 95% CI 0.01–0.75), HDL-CEC (RR 0.21, 95% CI 0.05–0.87) and HDL-associated PON1-arylesterase activity (RR 0.95, 95% CI 0.91–0.99). In patients who died during hospitalization, phospholipids, LCAT-phospholipase and PON1-arylesterase activities of HDL were lower. ConclusionsChanges in CEC and composition of HDL appear to be associated with the severity and outcome of acute ischemic stroke and could represent biomarkers that may inform risk stratification and management strategies in these patients.

High density lipoprotein heterogeneity & function among Indians with coronary artery disease.

Impaired high density lipoprotein (HDL) functionality has been shown to be associated with cardiovascular disease risk. The study was aimed to identify the alterations in HDL function [antioxidative activity (AOA)] and subfraction distribution between acute coronary syndrome (ACS) and stable coronary artery disease (SCAD) individuals and analysing the accuracy of HDL parameters to discriminate between the groups. HDL subfraction distribution analysis was performed in 200 coronary artery disease patients (ACS and SCAD) and 60 control individuals using dextran sulphate, heparin and manganese chloride precipitation method. In terms of HDL function, AOA was evaluated by dihydrorhodamine-based fluorescent cell-free assay and paraoxonase (PON1) enzyme paraoxonase and arylesterase activity. We found that higher AOA [odds ratio (95% confidence interval {CI})]: 0.09 (0.02-0.44), P<0.01 for SCAD; 0.008 (0.001-0.07), P<0.001 for ACS and higher PON1 activity [0.22 (0.8-0.59), P<0.01 for SCAD; 0.16 (0.06-0.4), P<0.001 for ACS] were associated with a lower odds of developing coronary artery disease (CAD). AOA of apoB-depleted serum was significantly correlated with HDL2-C/HDL3-C (HDL-cholesterol) ratio in controls (r=-0.31, P=0.01) and ACS (r=-0.18, P=0.04). It was observed that AOA and HDL subfraction distribution together could discriminate between the two groups of CAD with an accuracy of 72.8 per cent (P=0.004). Impaired AOA and altered subfraction distribution of HDL may be responsible for its diminished anti-athero protective activity and can discriminate between the two groups of CAD individuals.

Paraoxonase 1 Activity and Phenotype Distribution in Lumbar Disc Herniation Patients.

To compare the Paraoxonase 1 (PON1) activity and phenotype distribution between lumbar disc herniation (LDH) patients and healthy individuals. This research included 40 LDH patients and 42 healthy individuals. Spectrophotometric assays were performed to determine the serum PON1 and arylesterase activities. The PON1 ratio, which represents the salt-stimulated PON/ arylesterase level, demonstrated a trimodal distribution. This ratio was applied to identify the different phenotypes; QQ, QR, and RR of each subject. The LDH patients had lower PON1 activity than the healthy individuals (p < 0.05). LDH patients had a statistically significant QQ phenotype compared to the healthy subjects (p < 0.05). LDH patients had statistically lower PON1 activity, suggesting that the low PON1 activity and PON1 QQ phenotype may be a risk factor for LDH occurrence.

Association between Paraoxonase/Arylesterase Activity of Serum PON-1 Enzyme and Rheumatoid Arthritis: A Systematic Review and Meta-Analysis.

A decrease in serum paraoxonase (PON-1) and arylesterase (ARE) activity has been reported in rheumatoid arthritis (RA) patients and linked to chronic inflammation and impaired antioxidant defense. A systematic review and meta-analysis were performed to critically appraise the current evidence on plasma/serum concentrations of PON-1 and ARE activity in RA patients and healthy controls. The Web of Science, PubMed, Scopus, and Google Scholar databases were searched from inception to November 2021. We used random-effects meta-analysis. The risk of bias was estimated using the Joanna Briggs Institute Critical Appraisal Checklist tool. The certainty of the evidence was assessed with GRADE. The study complied with the PRISMA statements and was registered in PROSPERO (CRD42022345380). Seventeen studies reported PON-1 activity (1144 RA patients, 797 controls) and ten reported ARE activity (1367 RA patients, 1037 controls). RA patients had significantly lower PON-1 (SMD = -1.32, 95% CI -1.94 to -0.70; p &lt; 0.001) and ARE activity (SMD = -0.91, 95% CI -1.37 to -0.46; p &lt; 0.001). There was substantial heterogeneity (PON, I2 97%; ARE, 95.7%, p &lt; 0.001 for both). There was no publication bias. The pooled SMD values did not significantly change after sensitivity analysis. The certainty of the evidence was very low due to the observational nature of the studies and the large heterogeneity. Our meta-analysis has shown that both serum PON-1 and ARE activity are significantly lower in RA patients, suggesting a deficit in antioxidant defense mechanisms in this disease.

Paraoxonase 1 and atrial fibrillation: Is there a relationship?

Atrial fibrillation (AF) is associated with oxidative stress and inflammation. Paraoxonase-1 (PON1), circulates in blood bound to high-density lipoproteins and reduces systemic oxidative stress. The aim of this study was to evaluate PON1 serum concentration and PON1 arylesterase activity (AREase) in patients with AF. We studied a group of 67 patients with symptomatic paroxysmal or persistent AF admitted for cardioversion and a control group of 59 patients without AF. Clinical parameters, lipid profile, PON1 concentration and AREase were evaluated. A significant difference in serum PON1 concentration and in AREase was found among the two groups. In a multivariate linear regression model, the presence of AF was associated with low PON1 concentration (P = .022). The body mass index was also independently associated with PON1 values (P < .001). Only the high-density lipoproteins-cholesterol level was independently associated with AREase (P = .002). PON1 serum concentrations and AREase were diminished in patients with AF, and the presence of AF was independently associated with low PON1 values.

Sphingosine 1-Phosphate and Apolipoprotein M Levels and Their Correlations with Inflammatory Biomarkers in Patients with Untreated Familial Hypercholesterolemia.

High-density lipoprotein (HDL)-bound apolipoprotein M/sphingosine 1-phosphate (ApoM/S1P) complex in cardiovascular diseases serves as a bridge between HDL and endothelial cells, maintaining a healthy endothelial barrier. To date, S1P and ApoM in patients with untreated heterozygous familial hypercholesterolemia (HeFH) have not been extensively studied. Eighty-one untreated patients with HeFH and 32 healthy control subjects were included in this study. Serum S1P, ApoM, sCD40L, sICAM-1, sVCAM-1, oxLDL, and TNFα concentrations were determined by ELISA. PON1 activities were measured spectrophotometrically. Lipoprotein subfractions were detected by Lipoprint. We diagnosed FH using the Dutch Lipid Clinic Network criteria. Significantly higher serum S1P and ApoM levels were found in HeFH patients compared to controls. S1P negatively correlated with large HDL and positively with small HDL subfractions in HeFH patients and the whole study population. S1P showed significant positive correlations with sCD40L and MMP-9 levels and PON1 arylesterase activity, while we found significant negative correlation between sVCAM-1 and S1P in HeFH patients. A backward stepwise multiple regression analysis showed that the best predictors of serum S1P were large HDL subfraction and arylesterase activity. Higher S1P and ApoM levels and their correlations with HDL subfractions and inflammatory markers in HeFH patients implied their possible role in endothelial protection.

Paraoxonase 1 rs662 polymorphism, its related variables, and COVID-19 intensity: Considering gender and post-COVID complications.

In this study, we aimed to investigate the effect of paraoxonase 1 (PON1) rs662 polymorphism, arylesterase (ARE) activity, and the serum lipid profile in patients with coronavirus disease 2019 (COVID-19) in different stages of the disease considering post-COVID outcomes. A total of 470 COVID-19 patients (235 female and 235 male patients) were recruited into the study, and based on the World Health Organization (WHO) criteria, the patients were divided into three groups: moderate, severe, and critical. PON1 rs662 polymorphism was determined by the Alw 1 enzyme followed by agarose gel electrophoresis. Moreover, serum levels of triglycerides (TG), cholesterol (Chol), high-density lipoprotein-cholesterol (HDL-c), and low-density lipoprotein-cholesterol (LDL-c), as well as the level of the ARE activity of PON1 in the sera of patients were measured at the time of infection and one and three months after hospitalization. There was a significant relationship between the G allele and the severity of the disease. In addition, the probability of death in homozygous individuals (GG) was higher than in heterozygous patients (GA), and it was higher in heterozygous patients than in wild-type individuals (AA). There was also a significant relationship between the decrease in serum lipids and the intensity of COVID-19. On the contrary, at the onset of the disease, the HDL-c level and serum ARE activity were reduced compared to one and three months after COVID-19 infection. The findings of this study indicated the significant impact of PON1 rs662 polymorphism on ARE activity, lipid profiles, disease severity, and mortality in COVID-19 patients.

Assessment of the HER2, PDL1 and oxidative stress levels at the menopausal status of newly diagnosed breast cancer patients

Objective: This study aimed to estimate the levels of HER2, PD-L1 and oxidative stress in newly diagnosed breast cancer patients. Also, to estimate the probability of using HER2 and PD-L1 as a predictive marker on the occurrence of breast cancer in addition to study the effect of menopausal status at the level of HER2, PD-L1, oxidative stress and breast cancer risk factor.&#x0D; Methods: This study included 125 newly diagnosed breast cancer patients (53 premenopausal and 72 postmenopausal) from Oncology and Nuclear Medicine Hospital in Mosul, Iraq, and 100 apparently healthy women as a control group (44 premenopausal and 56 postmenopausal), during the period from Jan. 2021 to Jun. 2021. The ages of patients and control are matched, and it is ranged from 30-60 years.&#x0D; In this study we estimate the level of Human Epidermal Growth Factor Receptor 2 (HER2), Programmed Death -Ligand 1(PD-L1), total antioxidant capacity (T-AOC), arylesterase activity, uric acid level, malondialdehyde (MDA) level, peroxidase activity, lactoperoxidase activity and iron level at breast cancer patients and control.&#x0D; Results: The results show that there is a significant elevation in the level of HER2, PD-L1, malondialdehyde, peroxidase, lactoperoxidase and iron, and a significant decrease in the level of T-AOC, arylesterase and uric acid in the serum of breast cancer patients (pre and postmenopausal) compared with the control group (pre and postmenopausal).&#x0D; Also, increase the level of HER2 and oxidative stress at postmenopausal status for the control and patient groups. while PD-L1 level does not affect by menopausal status for both control and patient groups.&#x0D; Conclusion: The level of HER2, PD-L1, and oxidative stress was significantly increased in newly diagnosed breast cancer patients compared with the control group at the same menopausal status. Increase breast cancer risk factor at the postmenopausal status.

Lyso-DGTS Lipid Derivatives Enhance PON1 Activities and Prevent Oxidation of LDL: A Structure-Activity Relationship Study.

Paraoxonase 1 (PON1) plays a role in regulating reverse cholesterol transport and has antioxidative, anti-inflammatory, antiapoptotic, vasodilative, and antithrombotic activities. Scientists are currently focused on the modulation of PON1 expression using different pharmacological, nutritional, and lifestyle approaches. We previously isolated a novel active compound from Nannochloropsis microalgae—lyso-diacylglyceryltrimethylhomoserine (lyso-DGTS)—which increased PON1 activity, HDL-cholesterol efflux, and endothelial nitric oxide release. Here, to explore this important lipid moiety’s effect on PON1 activities, we examined the effect of synthesized lipid derivatives and endogenous analogs of lyso-DGTS on PON1 lactonase and arylesterase activities and LDL oxidation using structure–activity relationship (SAR) methods. Six lipids significantly elevated recombinant PON1 (rePON1) lactonase activity in a dose-dependent manner, and four lipids significantly increased rePON1 arylesterase activity. Using tryptophan fluorescence-quenching assay and a molecular docking method, lipid–PON1 interactions were characterized. An inverse correlation was obtained between the lactonase activity of PON1 and the docking energy of the lipid–PON1 complex. Furthermore, five of the lipids increased the LDL oxidation lag time and inhibited its propagation. Our findings suggest a beneficial effect of lyso-DGTS or lyso-DGTS derivatives through increased PON1 activity and prevention of LDL oxidation.

Low HDL Cholesterol Efflux Capacity Indicates a Fatal Course of COVID-19.

Plasma membrane cholesterol is required for proper trafficking and localization of receptors that facilitate severe acute respiratory syndrome coronavirus 2 infection. High-density lipoproteins (HDL) mobilize plasma membrane cholesterol, and HDL-cholesterol levels are associated with the severity of COVID-19 disease and mortality. However, HDL-cholesterol levels poorly reflect the function of this complex family of particles, and a detailed assessment of COVID-19-associated changes in HDL functionality and its prognostic value is lacking. In the present study, we assessed HDL cholesterol efflux capacity, HDL anti-inflammatory and antioxidant properties, and changes in HDL composition and metabolism in COVID-19 (n = 48) and non-COVID pneumonia patients (n = 32). COVID-19 infection markedly reduced the activity of lecithin-cholesteryl-acyltransferase and functional parameters of HDL, such as the cholesterol efflux capacity, arylesterase activity of paraoxonase 1, and anti-oxidative capacity of apoB-depleted serum when compared to non-COVID pneumonia at baseline, paralleled by markedly reduced levels of HDL-cholesterol. Of particular interest, low HDL cholesterol efflux capacity was associated with increased mortality risk in COVID-19 patients, independent of HDL-C levels. Our results highlight profound effects of COVID-19 infection on HDL function, metabolism, and composition. Low HDL cholesterol efflux capacity indicates a fatal course of COVID-19, independent of HDL-cholesterol levels.

Oxidative stress and PON1 (T172A/L55M) polymorphism: potential risk factors for Osteoarthritis

Objective: To investigate the role of oxidative stress in the progression of osteoarthritis with the genetic determinant of paraoxonase-1 enzyme L55M in osteoarthritis patients. Method: The case control study was carried out at the University of Karachi from April to November 2020, and comprised blood samples of female osteoarthritis patients aged &gt;50 years and healthy controls matched for age and gender. Oxidative stress was assessed by measuring lipid peroxidation product and protein carbonyl content. Activities of paraoxonase-1 paraoxonase and arylesterase were evaluated in the subjects. Protein expression of paraoxonase-1 was also analysed using western blot method. Paraoxonase-1 L55M (rs854560) polymorphism was determined using tetra-amplification-refractory mutation system polymerase chain reaction. Data was analysed using SPSS® Statistics 20.0. Results: Of the 103 subjects, 50(48.5%) were patients and 53(51.5%) were controls. The overall age range was 50-70 years. The extent of malondialdehyde (p&lt;0.001) and protein carbonyl content (p&lt;0.05) were increased significantly in the patients compared to the controls. Activity of paraoxonase and arylesterase was found decreased (p&lt;0.001) in patients compared to the controls. The prevalence of genotype MM was higher in the patients than the controls(p=0.001). L55M was more pronounced in patients suffering than the controls (p=0.01). Conclusion: The elevated levels of malondialdehyde and cabonylated protein content might be associated with osteoarthritis progression. Decreased serum paraoxonase-1 activity with L55M was the major consequence of oxidative stress in female osteoarthritis patients. Key Words: Osteoarthritis, Oxidative stress, Paraoxonase, Polymorphism.

Paraoxonase 1 gene polymorphisms in lipid oxidation and atherosclerosis development.

Paraoxonase 1 (PON1) is calcium-dependent aryldialkylphosphatase, thought to possess; anti-oxidant, anti-adhesion, anti-inflammatory, anti-thrombosis and anti-apoptosis effects, as well as lipid-modifying properties. Numerous clinical studies have shown associations between different PON1 polymorphisms and different cardiovascular pathologies. The rs622 (c.575A > G) and the rs854560 (c.163A > T) are the most studied PON1 SNPs in the coding region, with rs705381 (− 162A/G), rs854572 (− 909G/C) and rs705379 (− 108C/T) being the most studied SNPs in the regulatory PON1 gene region. The three major PON1 activities are aryldialkylphosphatase, arylesterase and lactonase activity. The different SNPs affect PON1 serum concentrations and enzyme activity, thus leading to pro-/anti-atherogenic effects. In that setting, it is very difficult to establish as to whether the genotype or phenotype of PON1 is primarily associated with cardiovascular risk. Given the current scientific evidence, PON1 genotyping might be reasonable in patients with high and very high cardiovascular risk.