Background: Recently, small dense low density lipoprotein (sdLDL) has been highlighted as a new risk factor for the coronary artery disease (CAD).Small dense LDLs are believed to be atherogenic since these particles are taken up more easily by arterial wall. They are readily oxidized and have reduced affinity for low density lipoprotein (LDL) receptor and increased affinity for arterial proteoglicans. LDL cholesterol is only a measure of the cholesterol level in the LDL whereas Apolipoprotein B (apo B) is a measure of the cholesterol levels of all the atherogenic particles, including very low density lipoprotein, intermediate density, and low density lipoproteins.Therefore, it might be a better marker than other traditional lipids. The aim of the present study was to evaluate the association between serum small dense LDL, Apolipoprotein B, Apolipoprotein A1 (apo A1) and apoB/apoA1 ratio and the coronary stenosis.Methods: 86 patients with coronary stenosis, 35 patients without coronary stenosis identified by angiography who were referred to Rajaii Heart Center, and 30 healthy individuals were studied. SdLDL was measured by a direct homogenous LDL-C assay in the supernatant of serum which remained after heparin-magnesium precipitation. Serum Apolipoprotein A1 and Apolipoprotein B were measured by using immunoturbidimetric method.Results: The results showed that the sdLDL levels were higher in patients with coronary stenosis than patients without coronary stenosis and healthy individuals (21.54±7.1, 16.88±4.4 and 15.45±5mg/dl, p=0.001, respectively). In addition the level of apoB (with stenosis: 113.71±21.8, without stenosis: 100.88±18.7 and healthy: 102.30±9.6, p=0.003) and apoB/apoA1 ratio (with stenosis: 1.100±0.24, without stenosis: 0.589±0.26 and healthy: 0.751±0.16, p=0.001) were significantly higher in patients with coronary stenosis. SdLDL levels were positively correlated with the level of apoB (r=0.589), apoB/apoA1 ratio (r=0.416), triglyceride (r=0.494), LDL-C (r=0.749), Total cholesterol (r=0.354) and were inversely correlated with the level of HDL-C (r=-0.586) (p<0.01).Conclusion: The elevated levels of small dense LDL, apoB and apoB/apoA1 ratio were associated with coronary artery stenosis.

Genetic variants of Apolipoprotein L1 (APOL1) have been recognized as a risk factor for kidney disease in people of African ancestry. APOL1 mediate renal damage in podocytes through necrosis, apoptosis and pyroptosis processes. APOL1 gene contains G1 and G2 alleles that mediate in increasing risk of renal disorders in African Americans. People who carry APOL1 risk alleles have a three to four-fold increase risk for non-diabetic renal disease (NDRD), Idiopathic focal segmental glomerulosclerosis (FSGS) and HIV-associated nephropathy (HIVAN). Therefore, identifying genetic factors involved in the pathogenesis of renal disorders, including APOL1 risk variants, may help to improve our understanding of kidney problems.

Introduction: Lipid level variations are among the most important risk factors for cardiovascular disease. Apolipoproteins play a the key role in lipid metabolism. In the present study the association of XbaI Apolipoprotein B polymorphisms on lipid variation was examined. Materials and Methods: A cross-sectional study was conducted on 849 subjects from the Tehran Lipid and Glucose Study population. Blood pressure was measured and the body mass index was calculated. TG, Chol, FBS, HDL-C and its subfractions, Apo B and Apo A1 levels were measured, and LDL-C concentration was calculated. A segment of the apo B gene was amplified by PCR and the polymorphism was revealed by RFLP using XbaI restriction enzyme.Results: Allele frequencies obtained for X+and X- were 27.6 % and 72.4%, respectively and were in the Hardy- Weinberg Equilibrium (HWE). The presence of the X+allele was significantly associated with increased total cholesterol (X+X+: 193±1.2 mg/ml vs. X-X-: 182±1.2 mg/ml, P 0.022) and Apolipoprotein B (X+X+: 116±1.5 mg/ml vs. X-X-: 104±1.4 mg/ml, P 0.024). The associations were significant even after adjustment for age, sex, BMI, smoking, diastolic and systolic blood pressure and fasting blood sugar.Conclusion: The observed allele frequencies were similar to other studies.Considering the association of XbaI polymorphisms with lipids factors, it is important to examine the relationship of Apo B gene variation and similar gene with lipids metabolisms.

Apolipoprotein E (apo E) is a structural constituent of several serum lipoprotein classes. It plays an important role in lipid metabolism by acting as a ligand for low-density lipoprotein (LDL) and chylomicron remnant receptors. Three common alleles called ε2, ε3 and ε4 have been described, which code for three protein isoforms (E2, E3 and E4). The polymorphism is clinically significant, and it has therefore become very important in epidemiological studies attempting to obtain complete information about apo E allele frequencies in populations around the world. In the present study, two point mutations coding amino acid residues 112 and 158 were amplified using the polymerase chain reaction (PCR) from DNA extracted from 100 Iranian subjects. Apo E genotypes were determined by restriction fragment length polymorphism (RFLP) and allelic frequencies were estimated by gene counting (ε2 = 0.01, ε3 = 0.88, ε4 = 0.11). The Hardy-Weinberg expectation of genotype distribution was calculated from the estimated allele frequencies and ax2-test was used to test for equilibrium (x2 = 0.487, P>0.05). Student’s t-test indicated that subjects with the two most common apo E genotypes (E4/E4, E3/E3) were different from each other in means serum total cholesterol (t = 3.1, P<0.01). Allele frequencies of the present study performed on Iranian subjects were similar to those of Japanese, Korean (Asian groups) Mexican and African American populations