RESUMO
In previous studies, it was demonstrated that lipid core nanoparticles (LDE) resemble the low-density lipoprotein structure and carrying the antiproliferative agent paclitaxel (PTX) strongly reduced atherosclerosis lesions induced in rabbits by cholesterol feeding. Currently, the aim was to verify whether combining LDE-PTX treatment with methotrexate (MTX) associated with LDE (LDE-MTX) could accelerate the atherosclerosis regression attained with single LDE-PTX treatment, after withdrawing the cholesterol feeding. Thirty-eight rabbits were fed 1% cholesterol chow for 8 weeks. Six of these rabbits were then euthanized for analyses of the aorta (controls). In the remaining rabbits, cholesterol feeding was withdrawn, and those 32 animals were allocated to 3 groups submitted to different 8-week intravenous treatments, all once/week: LDE-PTX (n = 10; 4 mg/kg), LDE-PTX + LDE-MTX (n = 11; 4 mg/kg), and LDE-alone (n = 11). Rabbits were then euthanized and aortas were excised for morphometric, immunohistochemical, and gene expression analyses. After cholesterol feeding withdrawal, in comparison with LDE-alone group, both LDE-PTX and LDE-PTX + LDE-MTX treatments had the ability to increase the regression of plaque areas: -49% in LDE-PTX and -59% for LDE-PTX + LDE-MTX. However, only LDE-PTX + LDE-MTX treatment elicited reduction in the intima area, estimated in -57%. Macrophage presence in aortic lesions was reduced 48% by LDE-PTX and 43% by LDE-PTX + LDE-MTX treatment. Matrix metalloproteinase 9 was reduced by either LDE-PTX (74%) or LDE-PTX + LDE-MTX (78%). Tumor necrosis factor α gene expression was reduced 65% by LDE-PTX and 79% by LDE-PTX + LDE-MTX. In conclusion, treatment with LDE-PTX indeed accelerated plaque reduction after cholesterol feeding; LDE-PTX + LDE-MTX further increased this effect, without any observed toxicity. These results pave the way for the use of combined chemotherapy to achieve stronger effects on aggravated, highly inflamed atherosclerotic lesions.
Assuntos
Aorta/efeitos dos fármacos , Doenças da Aorta/prevenção & controle , Aterosclerose/tratamento farmacológico , Fármacos Cardiovasculares/administração & dosagem , Colesterol na Dieta , Lipídeos/química , Metotrexato/administração & dosagem , Nanopartículas , Paclitaxel/administração & dosagem , Placa Aterosclerótica , Animais , Aorta/metabolismo , Aorta/patologia , Doenças da Aorta/sangue , Doenças da Aorta/patologia , Aterosclerose/sangue , Aterosclerose/patologia , Fármacos Cardiovasculares/química , Citocinas/metabolismo , Modelos Animais de Doenças , Composição de Medicamentos , Quimioterapia Combinada , Mediadores da Inflamação/metabolismo , Lipossomos , Masculino , Metaloproteinase 9 da Matriz/metabolismo , Metotrexato/química , Paclitaxel/química , CoelhosRESUMO
PURPOSE: After injection in the bloodstream, a lipid nanoparticle (LDE) resembling low-density lipoprotein (LDL) concentrates in atherosclerotic lesions of cholesterol-fed rabbits. Here, rabbits with atherosclerosis were treated with carmustine, an antiproliferative agent used in cancer chemotherapy, associated to LDE to investigate the effects on the lesions. METHODS: Twenty-seven male New Zealand rabbits were fed a 1 % cholesterol diet for 8 weeks. After 4 weeks nine animals were treated with intravenous saline solution, nine with intravenous LDE alone, and nine with intravenous LDE-carmustine (4 mg/kg, weekly for 4 weeks). RESULTS: LDE-carmustine reduced lesion size by 90 % compared to the controls. LDE-carmustine reduced the presence of macrophages, vascular smooth muscle cells, and regulatory T cells in the arterial intima, as well as the presence of matrix metallopeptidase-9, interleukin-1ß and TNF-α and lipoprotein receptors, namely LDL-receptor, LDL-related protein-1, scavenger receptor class B member 1. When injected alone, without association to carmustine, LDE was not different from injected saline solution. CONCLUSIONS: LDE-carmustine treatment resulted in marked reduction of lesion area, of the invasion of the arterial intima by macrophages and vascular smooth muscle cells and pro-inflammatory factors. Therefore, this new formulation shows great potential for therapy of atherosclerotic cardiovascular disease.
Assuntos
Aterosclerose/tratamento farmacológico , Carmustina/administração & dosagem , Lipídeos/administração & dosagem , Nanopartículas/administração & dosagem , Animais , Antineoplásicos Alquilantes/administração & dosagem , Antineoplásicos Alquilantes/farmacologia , Antineoplásicos Alquilantes/uso terapêutico , Aorta/efeitos dos fármacos , Aorta/metabolismo , Aorta/patologia , Aterosclerose/sangue , Aterosclerose/metabolismo , Aterosclerose/patologia , Carmustina/farmacologia , Carmustina/uso terapêutico , Colesterol na Dieta/administração & dosagem , Interleucina-1beta/metabolismo , Lipídeos/sangue , Lipídeos/química , Lipídeos/uso terapêutico , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Masculino , Metaloproteinase 9 da Matriz/metabolismo , Nanopartículas/química , Nanopartículas/uso terapêutico , Coelhos , Receptores de LDL/metabolismo , Receptores Depuradores Classe B/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
OBJECTIVES: Cholesterol-rich nanoemulsions (LDE) bind to low-density lipoprotein (LDL) receptors and after injection into the bloodstream concentrate in aortas of atherosclerotic rabbits. Association of paclitaxel with LDE markedly reduces the lesions. In previous studies, treatment of refractory cancer patients with etoposide associated with LDE had been shown devoid of toxicity. In this study, the ability of etoposide to reduce lesions and inflammatory factors in atherosclerotic rabbits was investigated. METHODS: Eighteen New Zealand rabbits were fed a 1% cholesterol diet for 60 days. Starting from day 30, nine animals were treated with four weekly intravenous injections of etoposide oleate (6 mg/kg) associated with LDE, and nine control animals were treated with saline solution injections. RESULTS: LDE-etoposide reduced the lesion areas of cholesterol-fed animals by 85% and intima width by 50% and impaired macrophage and smooth muscle cell invasion of the intima. Treatment also markedly reduced the protein expression of lipoprotein receptors (LDL receptor, LDL-related protein-1, cluster of differentiation 36, and scavenger receptor class B member 1), inflammatory cytokines (interleukin-1ß and tumor necrosis factor-α), matrix metallopeptidase-9, and cell proliferation markers (topoisomerase IIα and tubulin). CONCLUSION: The ability of LDE-etoposide to strongly reduce the lesion area and the inflammatory process warrants the great therapeutic potential of this novel preparation to target the inflammatory-proliferative basic mechanisms of the disease.