Masato Sawano

Effects of troglitazone on atherogenic lipoprotein phenotype in coronary patients with insulin resistance.

Insulin resistance is associated with atherogenic lipoprotein phenotype, including small dense LDL particle, hypertriglycemia and low HDL cholesterol levels. Troglitazone, a novel insulin sensitizing agent, may improve the associated lipid profile in patients with insulin resistance. We examined the effects of troglitazone (400 mg daily for 12 weeks) in 12 non-diabetic coronary patients (60+/-10 years), all of whom had hyperinsulinemic response to an oral glucose load. Troglitazone markedly reduced the insulin response. After the treatment, plasma triglycerides decreased by 32% (P<0.05), HDL cholesterol increased by 11%, (P<0.05) and LDL peak particle diameter increased from 24.7+/-0.3 to 25.5+/-0.5 nm (P<0.01). These lipidic improvements were associated with a significant rise in postheparin lipoprotein lipase levels (175+/-52 to 217+/-69 ng/ml, P<0.01). In patients with insulin resistance syndrome, troglitazone improved the atherogenic lipoprotein phenotype as well as hyperinsulinemia. Our data suggest that troglitazone therapy could reduce the atherosclerotic risk due to insulin resistance even in non-diabetic patients.

High prevalence of seropositivity for antibodies to Chlamydia-specific lipopolysaccharide in patients with acute coronary syndrome.

Background Results of recent studies have demonstrated that there is an association between infection with Chlamydia pneumoniae and coronary artery disease (CAD). Inflammatory response caused by chlamydial infection has been considered to contribute to the development of atherosclerosis in coronary arteries. Objective The aim of this study was to investigate the specific relations between chlamydial infection and coronary events in patients with CAD. Methods We measured serum levels of immunoglobulin A and G antibodies against Chlamydia spp.-specific lipopolysaccharide in 155 patients with CAD and 60 age-matched and sex-matched healthy controls by enzyme-linked immunosorbent assay. CAD patients were divided into groups of the patients with acute coronary syndrome [(ACS), n = 35], old myocardial infarction [(OMI), n = 60] and chronic coronary heart disease [(CCHD), n = 60]. Results Prevalence of both seropositive antibodies in the control group and CCHD group were not different. In contrast, in ACS group there were significantly higher prevalences of seropositive immunoglobulin A (46 versus 12%, P = 0.0001) and G (74 versus 45%, P = 0.005) antibodies and in OMI group there was a significantly higher prevalence of seropositive immunoglobulin A antibodies (28 versus 12%, P = 0.02). Furthermore, compared with CCHD group, in ACS group there were significantly higher prevalences of seropositive immunoglobulin A (P = 0.00006) and G (P = 0.002) antibodies and in OMI group there was a higher prevalence of seropositive immunoglobulin A (P = 0.01). Adjustment for confounding factors did not change these findings. Conclusions Infection with Chlamydia is significantly associated with ACS and OMI, but not with CCHD. These findings suggest that chronic and reactive infection with Chlamydia can lead to disruption of vulnerable plaque in patients with ACS.