Are Gujarati Asian Indians 'older' for their 'vascular age' as compared to their 'Chronological age'?

BACKGROUND: South Asians are known to carry higher burden of cardiovascular diseases when compared with their Caucasian counterparts. AIM: This study was designed to evaluate whether vascular age is advanced for Gujarati Asian Indians as matched to their chronological age in apparently healthy, asymptomatic population. We have also assessed the contributing risk factors for premature vascular ageing. DESIGN: It was cross-sectional study of 2483 individuals of Gujarat state in Western India having no past or present history of major illness including cardiovascular diseases. METHOD: The vascular age of the population was calculated using Framingham vascular age calculator. A relationship between risk factor prevalence and vascular ageing was evaluated using univariate analysis of variance. RESULTS: The mean chronological age of the study population was 46.8 (±10.35) years whereas mean vascular age was 53.34 (±16.05) years, and the difference (6.54±9.5) between both was statistically significant (P < 0.0001). Contributory risk factors for advanced vascular age apart from chronological age (75.4%) and male gender (66.2%) were the presence of dyslipidemia (60.4%) hypertension (57.34%) and increased waist circumference (WC) (male 39.7%, female 29%). Results of regression analysis showed that vascular age progression was highly associated with blood pressure (19.9, 95% CI: 14.34-27.63), followed by smoking (15.23, 95% CI: 8.4-27.59), and blood sugar (12.97, 95% CI: 3.48-48.25). CONCLUSION: The Gujarati Asian Indians are subjected to premature vascular ageing and henceforth routine screening for vascular age and risk factors prevalence is strongly advocated in this ethnic group.

Incorporation of bacterial membrane proteins into liposomes: factors influencing protein reconstitution.

Meningococcal and gonococcal outer membrane proteins were reconstituted into liposomes using detergent-mediated dialysis. The detergents octyl glucopyranoside (OGP), sodium cholate and Empigen BB were compared with respect to efficiency of detergent removal and protein incorporation. The rate of OGP removal was greater than for cholate during dialysis. Isopycnic density gradient centrifugation studies showed that liposomes were not formed and hence no protein incorporation occurred during dialysis from an Empigen BB containing reconstitution mixture. Cholate-mediated reconstitution yielded proteoliposomes with only 75% of the protein associated with the vesicles whereas all of the protein was reconstituted into the lipid bilayer during OGP-mediated reconstitution. Essentially complete protein incorporation was achieved with an initial protein-to-lipid ratio of 0.01:1 (w/w) in the reconstitution mixture; however, at higher initial protein-to-lipid ratios (0.02:1) only 75% protein incorporation was achieved. Reconstituted proteoliposomes were observed as large (>300 nm), multilamellar structures using cryo-electron microscopy. Size reduction of these proteoliposomes by extrusion did not result in significant loss of protein or lipid. Extruded proteoliposomes were unilamellar vesicles with mean diameter of about 100 nm.

Biophysical and antigenic characterization of gonococcal protein I incorporated into liposomes.

The major gonococcal outer membrane protein, protein I (Por), was reconstituted into liposomes composed of either 1-palmitoyl, 2-oleoyl phosphatidylcholine (POPC) or POPC:1-palmitoyl, 2-oleoyl phosphatidylethanolamine (POPE) (1:1 weight ratio) and the resulting proteoliposomes characterized with respect to their biophysical and antigenic properties. Isopycnic density gradient centrifugation studies established that essentially all of the protein was reconstituted into the lipid bilayer with no significant differences in incorporation seen as a function of lipid composition. Examination of Por orientation in these proteoliposomes revealed that over 80% of the protein was oriented facing outwards in the same 'hairpin loop' fashion found in the native bacterial membrane. Reconstituted Por proteoliposomes exhibited a mean vesicle diameter of > 0.5 micron but could be reduced by extrusion without significant loss of protein or lipid. These extruded systems were suitable for sterilization by terminal filtration. The antibody binding activities of various Por liposome formulations were determined using both anti-Por monoclonal antibodies and an immunized rabbit sera. No significant differences in antibody binding were observed as a function of proteoliposome lipid composition. However, consistently higher levels of antibody binding were obtained for Por liposomes prepared in this way compared with reconstituted systems prepared as described in earlier publications.