الفهرس 
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Abstract
Rheumatoid arthritis (RA) is the most common inflammatory joint disease, affecting 1-2% of the population worldwide, with women affected two to three times more commonly than men. RA is a chronic, progressive, inflammatory autoimmune disease associated with articular, extra-articular and systemic effects. It has been reported that RA affects 0.5-1% of the adult population of developed regions Although some patients have mild self-limited disease, many experience joint destruction, severe physical disability and multiple co-morbidities. Worldwide, the annual incidence of RA is approximately 3 cases per 10,000 populations, and the prevalence rate is approximately 1%, increasing with age and peaking between the ages of 35 and 50 years. RA affects all populations, though it is much more prevalent in some groups (e.g., 5-6% in some Native American groups) and much less prevalent in others (e.g., black persons from the Caribbean region). Population- and clinic-based studies were included from Brazil, Argentina, Mexico, Africa, and the Middle East, and these studies reported prevalence rates ranging from 0.14% to 0.55 and Prevalence of RA in rural Egypt is about 0.29%. The incidence of ASCVD events in patients with RA is more than three times that in the general population, and this increase is not entirely explained by traditional risk factors.
RA is associated with a spectrum of pro-atherogenic changes linked to systemic inflammation. Release of TNF-a, IL-6 and IL-1 from synovial tissue alters the function of distant tissues, including adipose tissue, skeletal muscle, liver and the vascular endothelium. These changes result in insulin resistance, dyslipidemia, increased global oxidative activity and endothelial dysfunction. RA-related dyslipidemia is characterized by low high-density lipoprotein (HDL) cholesterol, elevated triglyceride and lipoprotein(a) levels and an increase of small, dense low-density lipoprotein (LDL) species. Serum paraoxonase-1 (PON-1) is a high-density lipoprotein-associated, calcium-dependant, esterase with antioxidant and anti-atherogenic properties. The activity of PON1 has been implicated in the pathogenesis of many disease states, including metabolic syndrome, cardiovascular and Alzheimer’s disease. PON1 also plays a critical role in the metabolism and detoxification of insecticides and pesticides. PON1 in the human was principally responsible for the breakdown of lipid peroxides before they could accumulate on LDL. PON1 activity is one of the main mechanisms of LDL-C oxidation. Because of the key role of LDL-C oxidation in atherosclerosis, reduction of serum activity of PON1 may explain one of the essential mechanisms for increased risk of atherosclerosis and cardiovascular disease in RA patients PON1 hydrolyses lipid peroxidation products, and reduces the accumulation of them. Thus, PON1 prevents the acceleration of atherosclerosis and assumes an anti-atherogenic property. Recent articles indicated that PON1 reduce oxidative stress in serum and tissues, thus protecting against cardiovascular disease The aim of this work was to evaluate the relation between serum levels of Paraoxonase 1 enzyme activity and CCA-IMT as surrogate marker of ASCVD risk. It was conducted on (50) subjects aged from 25 years to 70 years from inpatient wards and outpatient clinics at Menoufia university hospitals from the period of May 2015 till December 2015, classified into two groups: Group (I): 30 RA patients and Group (II): 20 apparently healthy individuals of matched sex and age as a control group. Care was taken to exclude patients with known cardiovascular disease and those taking hypolipidemic drugs. All patients were subjected to thorough history taking, physical examination, investigations including Markers of inflammation: hsCRP and ESR, Lipid profile: total cholesterol, triglycerides, LDL, HDL, Carotid ultrasound imaging, and Determination of paraoxonase 1 activity. The present study revealed that: - All groups had been matched with no statistically significant differences between them as regarding age, sex and BMI (P value > 0.05). - There was a high prevalence of RA among females where the percentage of female RA patients in our study was 90%. - There was a statistically significant relationship between RA activity and dyslipidemia. Our data support previous work implicating abnormal HDL function as a potential mechanism and biomarker of ASCVD risk in RA patients. - A significant correlation between plasma PON1 activity and systemic inflammation as measured by the hsCRP level was noted in our RA cohort: Higher hsCRP levels were associated with lower paraoxonase 1 activity. - The incidence of atherosclerosis in RA patients - known by the carotid IMT as a surrogate marker - is relatively high and it’s correlated with the disease activity. - Our findings suggest a significant association of the PON1 activity with ASCVD risk in RA patients, as measured by the CIMT and presence of carotid plaque.