Vitamin E does not regress hypercholesterolemia-induced oxidative stress in heart.

Vitamin E suppresses the hypercholesterolemia-induced cardiac oxidative stress. The objectives were to investigate: if vitamin E regresses the hypercholesterolemia-induced oxidative stress in hearts and if regression is associated with decreases in the antioxidant reserve. The rabbits were assigned to 4 groups: I, regular diet (2-months); II, 0.25% cholesterol diet (2-months); III, 0.25% cholesterol diet (2-months) followed by regular diet (2-months); and IV, 0.25% cholesterol diet (2-months) followed by regular diet with vitamin E (2-months). Blood samples were collected before and at the end of protocol for the measurement of total cholesterol (TC). Hearts were removed at the end of the protocol under anesthesia for the assessment of oxidative stress parameters, malondialdehyde (MDA), and tissue chemiluminescent (CL) activity. High cholesterol diet increased the serum levels of TC, and regular diet with or without vitamin E reduced the TC levels to a similar extent. The MDA content of the heart in groups I, II, III, and IV were 0.074 ± 0.015, 0.234 ± 0.016, 0.183 ± 0.028 and 0.169 ± 0.016 nmol/mg protein, respectively. Regular diet following high cholesterol diet reduced the MDA levels (0.234 ± 0.016 vs. 0.183 ± 0.028 nmol/mg protein but vitamin E did not reduce the MDA levels. The cardiac-CL activities were similar in groups' I, II, and III (30.11 ± 0.7 × 10(6), 32.9 ± 1.43, and 37.92 ± 8.35 × 10(6) RLU/mg protein). The activity decreased in group IV, suggesting that vitamin E increased the antioxidant reserve while lowering serum cholesterol did not increase antioxidant reserve. In conclusion, hypercholesterolemia increases cardiac oxidative stress and regular diet regresses hypercholesterolemia-induced oxidative stress but vitamin E does not further regress hypercholesterolemia-induced cardiac oxidative stress. Vitamin E reduces oxidative stress in the heart tissue in spite of a decrease in CL activity (increase in antioxidant reserve).

Soluble receptors for advanced glycation end products (sRAGE) as a predictor of restenosis following percutaneous coronary intervention.

BACKGROUND: Interaction of advanced glycation end products (AGEs) with their receptor (RAGE) increases expression of inflammatory mediators (tumor necrosis factor alpha [TNF-α] and soluble vascular cell adhesion molecule-1 [sVCAM-1]) and induces oxygen radicals that are implicated in atherosclerosis. Balloon-injury-induced atherosclerosis is associated with increased expression of AGEs and RAGE. The soluble receptor for AGE (sRAGE), which acts as a decoy for RAGE ligands (AGEs), prevents atherosclerosis in this model. HYPOTHESIS: We evaluated: 1) whether post-percutaneous coronary intervention (PCI) restenosis is associated with low pre-PCI serum sRAGE, high serum AGEs, TNF-α, and sVCAM-1, and high AGE/sRAGE ratio; 2) whether pre-PCI and post-PCI levels of these markers are similar in patients with or without restenosis; and 3) whether sRAGE and AGE/sRAGE ratio have predictive value for post-PCI restenosis. METHODS: Angiography was performed in 46 patients with non-ST-segment elevation myocardial infarction for assessment of restenosis. Serum sRAGE, AGEs, TNF-α, and sVCAM-1 were measured in these patients and 20 control subjects. RESULTS: : Nineteen of the 46 patients developed post-PCI restenosis, which was associated with lower sRAGE and higher TNF-α and sVCAM-1 levels, and higher AGE/sRAGE ratio compared with patients without restenosis. Pre-PCI and post-PCI levels of these biomarkers were similar in both groups, except in patients with restenosis, in whom the post-PCI level of sRAGE was lower and TNF-α was higher than the pre-PCI levels. The sensitivity and negative predictive value of sRAGE were 100%, and were higher than those of AGE/sRAGE ratio in identifying post-PCI restenosis. CONCLUSIONS: Both low serum sRAGE levels and high AGE/sRAGE ratio have predictive value for post-PCI restenosis.

Modulation of high sensitivity C-reactive protein by soluble receptor for advanced glycation end products.

High sensitivity C-reactive protein (hs-CRP) is synthesized mainly by hepatocytes in response to tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), and interleukin-6 (IL-6). The interaction of advanced glycation end products (AGEs) with the receptor for advanced glycation end products (RAGE) increases the expression of the cytokines TNF-alpha, IL-1, and IL-6. Soluble receptor for advanced glycation end products (sRAGE) competes with RAGE for binding with AGEs. Hence, low sRAGE levels may increase interaction of AGEs with RAGE resulting in the increased production of cytokines. It is hypothesized that serum levels of sRAGE modulate serum levels of hs-CRP. The objectives are to determine if (i) serum levels of sRAGE are lower and those of TNF-alpha and hs-CRP are higher in non-ST-segment elevation myocardial infarction (NSTEMI) patients compared to control subjects; (ii) serum levels of TNF-alpha and hs-CRP are positively correlated; and (iii) sRAGE is negatively correlated with hs-CRP and TNF-alpha. The study consisted of 36 patients with NSTEMI and 30 age-matched healthy male subjects. Serum levels of sRAGE and TNF-alpha were determined by enzyme-linked immunoassay and hs-CRP was measured using near infrared immunoassay. Serum levels of sRAGE were lower, while those of TNF-alpha and hs-CRP were higher in patients with NSTEMI compared to controls. The levels of sRAGE were negatively correlated with those of TNF-alpha and hs-CRP, while TNF-alpha was positively correlated with hs-CRP in both the control subjects and NSTEMI patients. The data suggest that sRAGE modulates the synthesis of hs-CRP through TNF-alpha.