Paraoxonase-1 (PON-1) Arylesterase Activity Levels in Patients with Coronary Artery Disease: A Meta-Analysis

The Role of Polyphenols in Modulating PON1 Activity Regarding Endothelial Dysfunction and Atherosclerosis

The incidence and prevalence of cardiovascular diseases are still rising. The principal mechanism that drives them is atherosclerosis, an affection given by dyslipidemia and a pro-inflammatory state. Paraoxonase enzymes have a protective role due to their ability to contribute to antioxidant and anti-inflammatory pathways, especially paraoxonase 1 (PON1). PON1 binds with HDL (high-density lipoprotein), and high serum levels lead to a protective state against dyslipidemia, cardiovascular diseases, diabetes, stroke, nonalcoholic fatty liver disease, and many others. Modulating PON1 expression might be a treatment objective with significant results in limiting the prevalence of atherosclerosis. Lifestyle including diet and exercise can raise its levels, and some beneficial plants have been found to influence PON1 levels; therefore, more studies on herbal components are needed. Our purpose is to highlight the principal roles of Praoxonase 1, its implications in dyslipidemia, cardiovascular diseases, stroke, and other diseases, and to emphasize plants that can modulate PON1 expression, targeting the potential of some flavonoids that could be introduced as supplements in our diet and to validate the hypothesis that flavonoids have any effects regarding PON1 function.

Serum paraoxonase activities, nitric oxide, and malondialdehyde levels are altered in patients with primary fibromyalgia syndrome

BACKGROUND

Fibromyalgia patients who are exposed to extreme oxidative stress may face more severe clinical features or oxidative stress may be increased by the severity of the disease.

AIM

The purpose of these investigation were to determine serum paraoxonase activities (PON-1) and nitric oxide (NO) activities and malondialdehyde (MDA) level in fibromyalgia and whether there were any associations between these enzymes activities, MDA level, and clinical parameters.

METHODS

The study groups were consisted of 30 primer fibromyalgia patients and 30 healthy subjects. Clinical findings, pain severity, functional disability, general health status, anxiety, and depression assessed, and serum PON-1 activity, MDA, and NO levels were measured.

RESULTS

The primer fibromyalgia group had significantly higher MDA, low density lipoprotein-cholesterol (LDL-C), and decreased PON-1 activity, NO, and high density lipoprotein-cholesterol (HDL-C) with respect to controls. The paraoxonase activity was negatively correlated with MDA, LDL-C, Visual Analog Scale (VAS), Fibromyalgia Impact Questionnaire score (FIQ score), tender point score, age, and BDI score, while positively correlated with NO and HDL-C. MDA level was positively correlated with VAS, FIQ score, tender point score, age, and negatively correlated with NO level.

CONCLUSION

These results suggest that FMS patients have an alteration in levels of MDA, NO, and PON-1 activities. We think that impaired oxidant/antioxidant status may affect the symptoms of the disease. Also, they may be of importance in the complex physiopathologic mechanism behind the development of FMS.

Paraoxonase 1 activity in patients with Alzheimer disease: Systematic review and meta-analysis

Cumulating evidence links environmental toxicants, such as organophosphate (OP) pesticides, to the pathogenesis of Alzheimer's disease (AD). The calcium-dependent Paraoxonase 1 (PON1) can neutralize these toxicants with good catalytic efficiency, thus protecting from OP-induced biological damage. Although different previous studies have already partially described an association between PON1 activity and AD, this intriguing relationship has not yet been comprehensively examined. To fill this gap, we performed a meta-analysis of existing data comparing the PON1 arylesterase activity in AD and healthy subjects from the general population. Data were obtained by searching MEDLINE, Embase and CENTRAL, Google Scholar, and SCOPUS electronic databases for all studies published at any time up to February 2023, reporting and comparing the PON1- paraoxonase activity between AD patients and controls. Seven studies, based on 615 subjects (281 AD and 356 controls) met the inclusion criteria and were included into the final analysis. A random effect model revealed that PON1 arylesterase activity was significantly lower in the AD group compared to controls, exhibiting low level of heterogeneity (SMD = - 1.62, 95% CI = -2.65 to -0.58, p = 0.0021, I2 = 12%). These findings suggest that PON1 activity might be reduced in AD reflecting a major susceptibility to OPs neurotoxicity. Further studies should be conducted to definitely ascertain this link and to establish the cause-effect relationship between PON1 reduction and AD onset.

Proteomic Exploration of Paraoxonase 1 Function in Health and Disease

High-density lipoprotein (HDL) exhibits cardio- and neuro-protective properties, which are thought to be promoted by paraoxonase 1 (PON1), a hydrolytic enzyme associated with an HDL subfraction also enriched with an anticoagulant protein (PROS1) and amyloid beta-transport protein clusterin (CLU, APOJ). Reduced levels of PON1 activity, characterized biochemically by elevated levels of homocysteine (Hcy)-thiolactone, oxidized lipids, and proteins modified by these metabolites in humans and mice, are associated with pathological abnormalities affecting the cardiovascular system (atherothrombosis) and the central nervous system (cognitive impairment, Alzheimer's disease). The molecular bases of these abnormalities have been largely unknown. Proteomic and metabolic studies over the past decade have significantly contributed to our understanding of PON1 function and the mechanisms by which PON1 deficiency can lead to disease. Recent studies discussed in this review highlight the involvement of dysregulated proteostasis in the pro-oxidative, pro-atherothrombotic, and pro-amyloidogenic phenotypes associated with low PON1 activity.

Effects of cerium oxide (CeO2) on liver tissue in liver ischemia-reperfusion injury in rats undergoing desflurane anesthesia

INTRODUCTION

During liver surgery and transplantation, periods of partial or total vascular occlusion are inevitable and result in ischemia-reperfusion injury (IRI). Nanomedicine uses the latest technology, which has emerged with interdisciplinary effects, such as biomedical sciences, physics, and engineering, to protect and improve human health. Interdisciplinary research has brought along the introduction of antioxidant nanoparticles as potential therapeutics. The goal of this study was to investigate the effects of cerium oxide (CeO₂) administration and desflurane anesthesia on liver tissue in liver IR injury.

MATERIAL AND METHODS

Thirty rats were randomly divided into five groups: control (C), ischemia-reperfusion (IR), IR-desflurane (IRD), cerium oxide-ischemia reperfusion (CeO₂-IR), and cerium oxide-ischemia reperfusion-desflurane (CeO₂-IRD). In the IR, IRD, and CeO₂-IRD groups, hepatic ischemia was induced after the porta hepatis was clamped for 120 min, followed by 120 min of reperfusion. Intraperitoneal 0.5 mg/kg CeO₂ was administered to the CeO₂ groups 30 min before ischemia. Desflurane (6%) was administered to the IRD and CeO₂-IRD groups during IR. All groups were sacrificed under anesthesia. Liver tissue samples were examined under a light microscope by staining with hematoxylin-eosin (H&E). Malondialdehyde (MDA) levels, catalase (CAT), glutathione-s-transferase (GST), and arylesterase (ARE) enzyme activities were measured in the tissue samples.

RESULTS

The IR group had considerably more hydropic degeneration, sinusoidal dilatation, and parenchymal mononuclear cell infiltration than the IRD, CeO₂-IR, and CeO₂-IRD groups. Catalase and GST enzyme activity were significantly higher in the CeO₂-IR group than in the IR group. The MDA levels were found to be significantly lower in the IRD, CeO₂-IR, and CeO₂-IRD groups than in the IR group.

CONCLUSION

Intraperitoneal CeO₂ with desflurane reduced oxidative stress and corrected liver damage.

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

BACKGROUND/AIMS

Impaired 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.

METHODS

We 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.

RESULTS

CEC, 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.

CONCLUSIONS

Changes 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.

Oxidized High-Density Lipoprotein Induces Endothelial Fibrosis Promoting Hyperpermeability, Hypotension, and Increased Mortality

During systemic inflammation, reactive oxygen species (ROS) are generated in the bloodstream, producing large amounts of oxidized HDL (oxHDL). OxHDL loses the vascular protective features of native HDL, acquiring detrimental actions. Systemic inflammation promotes endothelial fibrosis, characterized by adhesion protein downregulation and fibrotic-specific gene upregulation, disrupting endothelial monolayer integrity. Severe systemic inflammatory conditions, as found in critically ill patients in the intensive care unit (ICU), exhibit endothelial hyperpermeability, hypotension, and organ hypoperfusion, promoting organ dysfunction and increased mortality. Because endothelial fibrosis disturbs the endothelium, it is proposed that it is the cellular and molecular origin of endothelial hyperpermeability and the subsequent deleterious consequences. However, whether oxHDL is involved in this process is unknown. The aim of this study was to investigate the fibrotic effect of oxHDL on the endothelium, to elucidate the underlying molecular and cellular mechanism, and to determine its effects on vascular permeability, blood pressure, and mortality. The results showed that oxHDL induces endothelial fibrosis through the LOX-1/NOX-2/ROS/NF-κB pathway, TGF-β secretion, and ALK-5/Smad activation. OxHDL-treated rats showed endothelial hyperpermeability, hypotension, and an enhanced risk of death and mortality, which was prevented using an ALK-5 inhibitor and antioxidant diet consumption. Additionally, the ICU patients showed fibrotic endothelial cells, and the resuscitation fluid volume administered correlated with the plasma oxHDL levels associated with an elevated risk of death and mortality. We conclude that oxHDL generates endothelial fibrosis, impacting blood pressure regulation and survival.

Role of Single Nucleotide Polymorphism L55M in the Paraoxonase 1 Gene as a Risk and Prognostic Factor in Acute Coronary Syndrome

The aim of the current study is to explore the possible role of L55M, (rs 854560, 163T > A) SNP as a predisposing factor for acute coronary syndrome (ACS) and to assess its potency as a prognostic biomarker for short (1 year) survival and for median (5 years) and 9-year long patients’ outcome. Methods: The current work is a prospective case-control study with 77 patients with acute coronary syndrome (53 with ST-elevation myocardial infarction, STEMI, 14 with non-ST-elevation myocardial infarction, NSTEMI and 10 with unstable angina, UA) and 122 control individuals. Patients were followed-up for 9 years. The genotyping for PON1 L55M SNP was carried on by PCR-RFLP method. Results: The results of the genotyping for PON1 L55M SNP showed a statistically significant difference (p = 0.023) between the controls and the whole group of patients with acute coronary syndrome, as the individuals with genotype with at least one variant M allele had about 2.5-fold higher risk for developing ACS than those which are homozygous of the wild-type L allele (LL genotype). In patients with variant M allele genotypes (LM + MM) which suffer from non-ST-segment elevation ACS (NSTEACS, i.e., UA or NSTEMI), the serum levels of total cholesterol (TC) and triacylglycerols (TAG) are significantly higher than in NSTEACS patients with LL genotype (p = 0.022 for TC and p = 0.015 for TAG). There was no significant difference in the survival rate at the 1st, 5th and 9th year of follow-up between ACS patients with different genotypes, although it is worth to note that in the subgroup of NSTEACS, all patients (n = 13) with variant M allele genotypes (LM + MM) were alive at the end of the first year, while 2 of the patients with LL genotype (18.2%) were dead. Conclusions: The results of our current study suggest that the variant M allele and the M allele genotypes (LM + MM) of the PON1 L55M polymorphism are risk factors for acute coronary syndrome, especially for patients with STEMI, but do not support the possible effect of this polymorphism on the clinical progression and outcome of the patients with ACS either in short or long follow-up periods.