Halleh Mahini

Antioxidant and anti-inflammatory role of paraoxonase 1: Implication in arteriosclerosis diseases

Paraoxonase 1 (PON1) is a hydrolytic enzyme with wide range of substrates, and capability to protect against lipid oxidation. Despite of the large number of compounds that can be hydrolyzed by paraoxonase, the biologically relevant substrates are still not clearly determined. There is a massive in vitro and in vivo data to demonstrate the beneficial effects of PON1 in several atherosclerosis-related processes. The enzyme is primarily expressed in liver; however, it is also localized in other tissues. PON1 attracted significant interest as a protein that is responsible for the most of antioxidant properties of high-density lipoprotein (HDL). Several bioactive molecules such as dietary polyphenols, aspirin and its hydrolysis product salicylate, are known to stimulate PON1 transcription activation in mouse liver and HepG2 cell line. Studies on the activity, function, and genetic makeup have revealed a protective role of PON1. Some striking data were obtained in PON1 gene knockout and PON1 transgenic mouse models and in human studies. The goal of this review is to assess the current understanding of PON1 expression, enzymatic and antioxidant activity, and its atheroprotective effects. Results from in vivo and in vitro basic studies; and from human studies on the association of PON1 with coronary artery disease (CAD) and ischemic stroke will be discussed.

Serum tumor necrosis factor-α, interleukin-6, monocyte chemotactic protein-1 and paraoxonase-1 profiles in women with endometriosis, pcos, or unexplained infertility

ObjectiveTo investigate the serum levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), monocyte chemotactic protein-1 (MCP-1), and Paraoxonase-1 (PON-1) during fertility treatment of women with endometriosis (Endo), PCOS or unexplained infertility (Unexpl).MethodsThirty-six patients with Endo, PCOS or Unexpl undergoing controlled ovarian stimulation for IVF or IUI were consented and their serum, on day-3 (baseline) and at the end of FSH treatment (peak), was collected and investigated for levels of TNF-α, IL-6, MCP-1, and PON-1. Correlations, ANOVA and Students t-test were used for statistical analysis.ResultsPeak serum levels of IL-6, MCP-1 and PON-1 were positively correlated to E2 peak levels. TNF-α levels were inversely correlated to estradiol levels and they were lower in patients who ultimately became pregnant when compared to non-pregnant (P < 0.05). Mean TNF-α levels were significantly higher in Unexpl group (P < 0.05). The mean levels of IL-6, and MCP-1 were significantly (p < 0.05) higher in women with PCOS compared with Endo and Unexpl. No differences were found between the three clinical groups in patient’s age, BMI, Day-3 FSH, PON-1 and pregnancy outcome.ConclusionCirculating cytokine levels were influenced by ovarian stimulation, as demonstrated by increased levels of IL-6, MCP-1 and PON-1, and decreased level of TNF-α at the end of controlled ovarian stimulation. While evidence of relationship between circulating cytokines with mild endometriosis was not found, PCOS was associated with elevated serum IL-6 and MCP-1 but lower TNF-α concentration. Unexplained infertility was associated with elevated TNF-α level. No relationship between serum PON-1 concentration and PCOS, mild endometriosis or unexplained infertility was noted.

Dietary Oxidized Linoleic Acid Modulates Plasma Lipids beyond Triglycerides Metabolism

Introduction Triglyceride (TG) is an independent risk factor for coronary heart disease. Previous work has shown that short-term supplementations of mouse chow with oxidized linoleic acid (OxLA) significantly reduce the level of plasma triglycerides. Study Objective This study aims to determine the effects of longer-term supplementation of mouse chow with various concentrations of oxidized linoleic acid (OxLA) on plasma triglycerides. Study Design The study consisted of forty C57BL/6 wildtype mice divided into four groups (n = 10). Two groups were kept as controls. One control group (P) was fed plain chow and the second control group (C) was fed chow supplemented with linoleic acid. The other two experimental groups (A) and (B) were fed oxidized linoleic acid supplemented chow in the following doses: 9 mg/day of oxidized linoleic acid and 18 mg/day of oxidized linoleic acid/mouse. Results and Conclusion Mice that were on a diet supplemented with the higher dose of oxidized linoleic acid showed a 39% decrease in hepatic PPAR-α and a significant decrease in the plasma HDL levels compared to the mice that were fed diets of plain and linoleic acid supplemented chow. Interestingly, the longer-term consumption of oxidized linoleic acid may predispose to atheropathogenesis.