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Abstract: Human amniotic fluid-derived stem (AFS) cells, similarly to embryonic stem cells, could possess privileged immunological characteristics suitable for a successful transplantation even in a discordant xenograft system. We investigated whether AFS cells could be fruitfully used in a rat model of myocardial infarction. c-kit immunomagnetic-sorted AFS cells were characterized by flow cytometric analysis and cytospins as well as reverse-transcription polymerase chain reaction, Western blotting and immunocytochemistry for cardiovascular differentiation markers. In vitro, AFS cell phenotypic conversion was assayed by cardiovascular-specific induction media or co-cultured with rat neonatal cardiomyocytes. AFS cells showed mRNAs and/or protein for endothelial (angiopoietin, CD146) and smooth muscle (smoothelin) cells, and cardiomyocyte (Nkx2.5, MLC-2v, GATA-4, β-MyHC) markers. Acquisition of a cardiomyocyte-like phenotype in rare AFS cells could be seen only in co-cultures with rat neonatal cells. In vivo, AFS cells xenotransplantated in a rat model of myocardial infarction, with or without cyclosporine treatment, or in intact heart from immuno-competent or immuno-deficient animals were acutely rejected due to the different recruitment of recipient CD4+, CD8+ T and B lymphocytes, NK cells and macrophages. This reaction is most likely to be linked to expression of B7 co-stimulatory molecules CD80 and CD86 as well as macrophage marker CD68 on AFS cells. Xenotransplanted AFS cells gave also rise in some animals to cell masses in the subendocardium and myocardium suggestive of a process of chondro-osteogenic differentiation. Despite AFS cells in vitro can differentiate to some extent to cells of cardiovascular lineages, their in vivo use in xenotransplantation for cell therapy of myocardial infarction is hampered by their peculiar immunogenic properties and phenotypic instability. [Copyright &y& Elsevier]

: ObjectivesWe investigated the potential association between −514 C→T polymorphism in the promoter of the hepatic lipase gene (LIPC) and the prevalence of inflammatory cells in the plaque of patients with severe carotid artery stenosis.: BackgroundThis common LIPC polymorphism has been related to the presence of an atherogenic lipoprotein pattern.: MethodsWe studied 68 consecutive patients undergoing carotid endarterectomy. The LIPC genotype was determined by polymerase chain reaction. Endarterectomy specimens were examined by immunocytochemistry using monoclonal antibodies for smooth muscle cells, macrophages, or lymphocytes.: ResultsIn 50 of 68 patients who had evidence of previous ipsilateral ischemic events, 36 (72%) were carriers of the CC genotype, whereas only 14 (28%) were carriers of the CT/TT genotype (p = 0.002). Among the 18 patients without evidence of events, the two genotypes were equally distributed (9 vs. 9). The low-density lipoprotein (LDL) particles were denser in CC than in CT/TT genotype carriers (flotation rate: 0.315 ± 0.025 vs. 0.356 ± 0.019, p < 0.0005). The CC genotype was associated with an abundance of macrophages (6.7 ± 3.5 vs. 2.1 ± 2.1 cells/area unit in the CT/TT group, p < 0.0005) and a reduced number of smooth muscle cells (6.9 ± 6.2 vs. 14.5 ± 6.4 in the CT/TT group, p < 0.0005) in the plaque. An inverse relationship was found between LDL buoyancy and the number of macrophages in the plaque (r = −0.639, p < 0.0005).: ConclusionsWe provide evidence, for the first time, that LIPC promoter −514 C→T polymorphism, by modulating LDL density, significantly affects the number of macrophages in the plaque and possibly affects the occurrence of cerebrovascular events in patients with carotid artery stenosis. [Copyright &y& Elsevier]