Effects of linseed consumption for a short period of time on lipid profile and atherosclerotic lesions in rabbits fed a hypercholesterolaemic diet.

Linseed contains biologically active substances, such as lignans, fibres and linoleic acid, which are believed to provide cardioprotective effects. The objective of the present study was to assess the potential hypolipaemic, anti-atherogenic and anti-inflammatory effects of linseed consumption using an experimental animal model, with rabbits fed a hypercholesterolaemic diet (1 % cholesterol extracted from lyophilised egg). A total of twenty white male rabbits were selected and divided into two groups: group I (GI), control group, ten rabbits; group II (GII), ten rabbits. The animals were fed a hypercholesterolaemic diet for 56 d. For the GII diet, ground linseed was added from day 29 through to day 56. Animals underwent aortic arch and descending aorta dissection on day 56 for histological, morphometric and immunohistochemical analysis. At the end of the experiment, GII animals presented with lower levels of total cholesterol (TC, 10 068·3 v. 16 767·0 mg/l; P < 0·05) and lower levels of LDL-cholesterol (LDL-C; 10 743·2 v. 15 961·2 mg/l; P < 0·05) when compared with the GI control group. There was no significant difference in serum HDL-cholesterol and TAG between the two groups. Almost all animals exhibited type III atherosclerotic lesions in the descending aorta. There was no statistically significant difference between the intima area and the intima:media layer area ratio in both groups. There was no difference between the positive areas for vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 molecules between the groups. Linseed consumption showed hypolipaemic action by reducing LDL-C and TC levels; however, this cholesterol-lowering effect did not reduce the atherosclerotic lesions induced by a hypercholesterolaemic diet (1 % cholesterol) for a short period of time.

Rosiglitazona e lesão vascular em coelhos hipercolesterolêmicos: avaliação da formação neointimal / Rosiglitazone and vascular injury in hypercholesterolemic rabbits: neointimal formation assessment / Rosiglitazona y lesión vascular en conejos hipercolesterolémicos

FUNDAMENTO: O uso da rosiglitazona tem sido o objeto de extensas discussões. OBJETIVO: Avaliar os efeitos da rosiglitazona nas artérias ilíacas, no local da injúria e na artéria contralateral, de coelhos hipercolesterolêmicos submetidos à lesão por cateter-balão. MÉTODOS: Coelhos brancos machos receberam uma dieta hipercolesterolêmica através de gavagem oral por 6 semanas e foram divididos em 2 grupos: grupo rosiglitazona (GR - 14 coelhos tratados com rosiglitazona por 6 semanas) e grupo controle (GC - 18 coelhos sem rosiglitazona). Os animais foram submetidos a lesão por cateter-balão na artéria ilíaca direita no 14º dia. RESULTADOS: Na artéria ilíaca contralateral, não houve diferença significante na razão entre as áreas intimal e medial (RIM) entre os grupos GR e GC. A rosiglitazona não reduziu a probabilidade de lesões tipo I, II ou III (72,73 por cento vs 92,31 por cento; p=0,30) e lesões tipo IV ou V (27,27 por cento vs 7,69 por cento; p=0,30). Na artéria ilíaca homolateral, a área intimal era significantemente menor no GR quando comparado ao GC (p = 0,024). A área luminal era maior no GR quando comparado ao GC (p < 0,0001). Houve uma redução significante de 65 por cento na IMR no GR quando comparado ao GC (p = 0,021). Nenhum dos critérios histológicos para lesões ateroscleróticas tipos I a V (American Heart Association) foram encontrados na artéria ilíaca homolateral. CONCLUSÃO: Esses achados demonstram que a administração de rosiglitazona por 6 semanas impede a aterogênese no local da lesão, mas não em um vaso distante do sítio da lesão.

BACKGROUND: Rosiglitazone has been the focus of extensive discussion. OBJECTIVE: To evaluate the effects of rosiglitazone on iliac arteries, both at the injury site and the contralateral artery, of hypercholesterolemic rabbits undergoing balloon catheter injury. METHODS: White male rabbits were fed a hypercholesterolemic diet by oral gavage for 6 weeks and divided into two groups as follows: rosiglitazone group (14 rabbits treated with rosiglitazone during 6 weeks) and the control group (18 rabbits without rosiglitazone). Animals underwent balloon catheter injury of the right iliac artery on the 14th day. RESULTS: In the contralateral iliac artery, there was no significant difference in the intima/media layer area ratio (IMR) between the control and rosiglitazone groups. Rosiglitazone did not reduce the probability of type I, II, or III lesions (72.73 percent vs 92.31 percent; p=0.30) and type IV or V lesions (27.27 percent vs 7.69 percent; p=0.30). As for the homolateral iliac artery, the intimal area was significantly lower in the rosiglitazone group, as compared to the control group (p = 0.024). The luminal layer area was higher in the rosiglitazone group vs. the control group (p < 0.0001). There was a significant reduction of 65 percent in the IMR in the rosiglitazone group vs the control group (p = 0.021). None of the histological criteria for type I-V atherosclerotic lesions (American Heart Association) were found in the homolateral iliac artery. CONCLUSION: These findings demonstrate that rosiglitazone given for 6 weeks prevents atherogenesis at the injury site, but not in a vessel distant from the injury site.

FUNDAMENTO: El uso de rosiglitazona ha estado siendo el objeto de extensas discusiones. OBJETIVO: Evaluar los efectos de la rosiglitazona en las arterias ilíacas, en el local de la injuria y en la arteria contralateral, de conejos hipercolesterolémicos sometidos a la lesión por catéter-balón. MÉTODOS: Conejos blancos machos recibieron una dieta hipercolesterolémica a través de gavage oral por 6 semanas y se los dividieron en 2 grupos: grupo rosiglitazona (GR - 14 conejos tratados con rosiglitazona por 6 semanas) y grupo control (GC - 18 conejos sin rosiglitazona). Los animales se sometieron a lesión por catéter-balón en la arteria ilíaca derecha en el 14º día. RESULTADOS: En la arteria ilíaca contralateral, no hubo diferencia significativa en la razón entre las áreas íntima y media (RIM) entre los grupos GR y GC. La rosiglitazona no redujo la probabilidad de lesiones tipo I, II ó III (72,73 por ciento vs 92,31 por ciento; p=0,30) y lesiones tipo IV ó V (27,27 por ciento vs 7,69 por ciento; p=0,30). En la arteria ilíaca homolateral, el área intima era significantemente menor en el GR cuando comparado al GC (p = 0,024). El área luminal era mayor en el GR cuando comparado al GC (p < 0,0001). Hubo una reducción significante del 65 por ciento en la IMR en el GR cuando comparado al GC (p = 0,021). Ningún de los criterios histológicos para lesiones ateroscleróticas tipos I a V (American Heart Association) se encontraron en la arteria ilíaca homolateral. CONCLUSIÓN: Estos hallazgos demuestran que la administración de rosiglitazona por 6 semanas impide la aterogénesis en el local de la lesión, pero no en un vaso distante del sitio de la lesión.

Rosiglitazone and vascular injury in hypercholesterolemic rabbits: neointimal formation assessment.

BACKGROUND: Rosiglitazone has been the focus of extensive discussion. OBJECTIVE: To evaluate the effects of rosiglitazone on iliac arteries, both at the injury site and the contralateral artery, of hypercholesterolemic rabbits undergoing balloon catheter injury. METHODS: White male rabbits were fed a hypercholesterolemic diet by oral gavage for 6 weeks and divided into two groups as follows: rosiglitazone group (14 rabbits treated with rosiglitazone during 6 weeks) and the control group (18 rabbits without rosiglitazone). Animals underwent balloon catheter injury of the right iliac artery on the 14th day. RESULTS: In the contralateral iliac artery, there was no significant difference in the intima/media layer area ratio (IMR) between the control and rosiglitazone groups. Rosiglitazone did not reduce the probability of type I, II, or III lesions (72.73% vs 92.31%; p=0.30) and type IV or V lesions (27.27% vs 7.69%; p=0.30). As for the homolateral iliac artery, the intimal area was significantly lower in the rosiglitazone group, as compared to the control group (p = 0.024). The luminal layer area was higher in the rosiglitazone group vs. the control group (p < 0.0001). There was a significant reduction of 65% in the IMR in the rosiglitazone group vs the control group (p = 0.021). None of the histological criteria for type I-V atherosclerotic lesions (American Heart Association) were found in the homolateral iliac artery. CONCLUSION: These findings demonstrate that rosiglitazone given for 6 weeks prevents atherogenesis at the injury site, but not in a vessel distant from the injury site.

Use of rosiglitazone before and after vascular injury in hypercholesterolemic rabbits: Assessment of neointimal formation.

OBJECTIVES: To analyse the effects of rosiglitazone administered at different times on neointimal formation in hypercholesterolemic rabbits following vascular injury. METHODS: Thirty-nine rabbits on a hypercholesterolemic diet were included. The animals underwent balloon catheter injury to the right iliac artery on day 14. They were divided into three groups as follows: control group, 13 rabbits without rosiglitazone; group I, 13 rabbits treated with rosiglitazone (3 mg/Kg body weight/day) for 28 days after the vascular injury; and group II, 13 rabbits treated with rosiglitazone (3 mg/Kg body weight/day) during all the experiment (42 days). Histological analysis was done by an experienced pathologist who was unaware of the rosiglitazone treatment. Histomorphometric parameters were performed by calculation of the luminal and intimal layer area, and intima/media layer area ratio (the area of the intimal layer divided by the area of the medial layer). RESULTS: Intimal area was significantly lower in group II vs. CG (p = 0.024) and group I (p = 0.006). Luminal layer area was higher in group II vs. CG (p < 0.0001) and group I (p < 0.0001). Intima/media layer area ratio was equal between CG and group I. Intima/media layer ratio area was significantly lower in group II vs. control group (p < 0.021) and group I (p < 0.003). There was a significant reduction of 65% and 71% in intima/media layer area ratio in group II vs. control group and group I, respectively. CONCLUSION: Pretreatment with rosiglitazone in hypercholesterolemic rabbits submitted to vascular injury significantly reduces neointimal formation.

Conceitos atuais e perspectivas na prevenção da degeneração macular relacionada à idade / Current concepts and perspectives in the prevention of age-related macular degeneration

Os autores fazem revisão bibliográfica a respeito dos principais antioxidantes utilizados na prática diária atualmente para prevenção da progressão da degeneração macular relacionada com a idade (DMRI), enfatizando o mecanismo de ação de cada substância bem como as possíveis complicações relacionadas ao uso excessivo destes componentes.

The authors prepare a literature review about the main antioxidants used in daily practice for the prevention of age-related macular degeneration progression (AMD), emphasizing the mechanism of action of each substance as well as the possible complications related to the overuse of such components.

Effects of rosiglitazone on contralateral iliac artery after vascular injury in hypercholesterolemic rabbits.

BACKGROUND: The objective was to evaluate the effects of rosiglitazone on iliac arteries of hypercholesterolemic rabbits undergoing balloon catheter injury in the contralateral iliac arteries. METHODS: White male rabbits were fed a hypercholesterolemic diet for 6 weeks and divided into two groups as follows: rosiglitazone group, 14 rabbits treated with rosiglitazone (3 mg/Kg body weight/day) during 6 weeks; and control group, 18 rabbits without rosiglitazone treatment. All animals underwent balloon catheter injury of the right iliac artery on the fourteenth day of the experiment. RESULTS: There was no significant difference in intima/media layer area ratio between the control group and the rosiglitazone group. Rosiglitazone did not reduce the probability of lesions types I, II, or III (72.73% vs. 92.31%; p = 0.30) and types IV or V (27.27% vs. 7.69%; p = 0.30). There were no differences in the extent of collagen type I and III deposition or in the percentage of animals with macrophages in the intima layer. The percentage of rabbits with smooth muscle cells in the intima layer was higher in rosiglitazone group (p = 0.011). CONCLUSION: These findings demonstrate that rosiglitazone given for 6 weeks did not prevent atherogenesis at a vessel distant from the injury site.