Study of Paraoxonase1 Activity and Lipid Peroxidation in Selected Male Patients with the Metabolic Syndrome,MOMAMAD MAHMOUD, NABILA A. EL-LITHY, DAWOUD F. HABIB, HIBA S. ASSAL, MOHAMED ABOU EL-FOTOUH and MAGDY A. ASHOUR
Abstract
Today, the metabolic syndrome is one of the major public health concerns as its prevalence increases worldwide with a subsequent predisposition to type 2 diabetes and cardiovas-cular disease and even mortality. Paraoxonase1 (PON1) is a high-density lipoprotein (HDL)-associated enzyme capable of hydrolyzing diverse substrates including oxidized phospho-lipids. The reactive oxygen species induced oxidative stress may play a role in the development of insulin resistance. The oxidative stress causes increased tissue/cellular damage manifested by lipid peroxidation.
The Aim of this Work: Was to study PNO1 activity and lipid peroxidation in male patients with the metabolic syn-drome. The patients were neither diabetic nor hypertensive apart from mild to moderate hypertension. They were also free from coronary artery disease.
Subjects and Methods: 45 male patients the criteria of the metabolic syndrome according to the National Cholesterol Education Program/Adult Treatment Panel III (NCEP) were chosen in the study. They were chosen also to be nondiabetic, nonsmoker, non hypertensive or with mild to moderate degree of hypertension and not suffering coronary artery disease. 15 apparently healthy male, not fulfilling the criteria of the metabolic syndrome and age & culture matched, constituted the control group. All the chosen subjects underwent thorough clinical examination specially measuring waist circumference and the blood pressure. Fasting and postprandial serum glucose, high and low density lipoproteins, serum triglycerides, paraoxonase1 activity & malonaldehyde were assayed.
Results: Compared with the controls, the patients had significantly higher level of serum triglycerides, low-density lipoprotein-cholesterol (LDL-C), fasting and postprandial glucose and fasting insulin. There were also significant higher measurements of waist circumference and systolic & diastolic blood pressure. However the patients had lower high density lipoprotein-cholesterol (HDL-C). They were more insulin resistant as measured by HOMA index. Patients had higher serum malondialdhyde level and lower serum paraoxonase1 (PNO1) activity when compared with the controls. There were positive correlations between HOMA index and waist circum-ference, fasting and postprandial serum glucose, serum trig-lycerides, serum malondialdhyde level. HOMA index was negatively correlated with HDL-C and PONI activity. There were positive correlations of PONI activity with HDL-C and
serum triglycerides and no correlation waist circumference, while there were negative correlation of PONI activity with blood pressure and serum glucose levels. There were negative correlations of PONI activity with HOMA index and serum malondialdhyde level. Serum malondialdhyde level showed positive correlation with waist circumference, blood pressure levels, serum glucose levels, serum triglycerides. Serum malondialdhyde level showed negative correlation with PONI activity and HOMA index. It showed no correlation with HDL-C.
In Conclusion: Male patients with MetS, who were nor-motensive or not severely hypertensive & not yet developed DM or cardiovascular complications of MetS, had diminished serum paraoxonase 1 activity & increased lipid peroxidation. These were correlated with the degree of insulin resistance. These results pointed strongly to increased oxidative stress. The increased oxidative stress along with their atherogenig lipid profile indicated a proatherogenic state. We recommend that clinicians should deal with these hidden factors aiming to avoid MetS complications.