CESAR ISAAC
Projetos de Pesquisa
Unidades Organizacionais
LIM/04 - Laboratório de Microcirurgia, Hospital das Clínicas, Faculdade de Medicina - Líder
3 resultados
Resultados de Busca
Agora exibindo 1 - 3 de 3
- Short-term effects of 7-ketocholesterol on human adipose tissue mesenchymal stem cells in vitro(2014) LEVY, Debora; RUIZ, Jorge Luis Maria; CELESTINO, Andrea Turbuck; SILVA, Suelen Feitoza; FERREIRA, Adilson Kleber; ISAAC, Cesar; BYDLOWSKI, Sergio PauloOxysterols comprise a very heterogeneous group derived from cholesterol through enzymatic and nonenzymatic oxidation. Among them, 7-ketocholesterol (7-KC) is one of the most important. It has potent effects in cell death processes, including cytoxicity and apoptosis induction. Mesenchymal stem cells (MSCs) are multipotent cells characterized by self-renewal and cellular differentiation capabilities. Very little is known about the effects of oxysterols in MSCs. Here, we describe the short-term cytotoxic effect of 7-ketocholesterol on MSCs derived from human adipose tissue. MSCs were isolated from adipose tissue obtained from two young, healthy women. After 24 h incubation with 7-KC, mitochondrial hyperpolarization was observed, followed by a slight increase in the level of apoptosis and changes in actin organization. Finally, the IC50 of 7-KC was higher in these cells than has been observed or described in other normal or cancer cell lines.
- Evaluation of Radiosterilized Glyercerolated Amniotic Membranes as a Substrate for Cultured Human Epithelial Cells(2020) PAGGIARO, Andre O.; MATHOR, Monica B.; TEODORO, Walcy R.; ISAAC, Cesar; CAPELOZZI, Vera L.; GEMPERLI, RolfHuman amniotic membrane (HAM) is a biomaterial with biological properties beneficial to tissue repair, serving as a substrate for cell cultivation. Irradiation is used for tissue sterilization, but can damage the HAM structure. The objective of this paper was to construct a skin substitute, composed of human keratinocytes cultured on glycerolated HAMs, and to evaluate the influence radiation on subsequent cell culture growth. Four batches of HAMs were glycerolated, and half of them were radio-sterilzed with 25 kGy. Non-irradiated glycerolated HAM (ni-HAM) and irradiated glycerolated HAM (i-HAM) samples were then de-epithelized and analyzed using optical microscopy (Picrossirius staining), immunofluorescence and electron microscopy. Subsequently, keratinocytes were cultured on ni- and i-HAMs, and either immersed or positioned at the air-liquid interface. The basement membranes of the ni-HAM group remained intact following de-epithelialization, whereas the i-HAM group displayed no evidence or remnant presence of these membranes. Concerning the keratinocyte cultures, the ni-HAM substrate promoted the growth of multi-layered and differentiated epithelia. Keratinocytes cultured on i-HAM formed epithelium composed of three layers of stratification and discrete cell differentiation. The glycerolated HAM was compatible with cultured epithelia, demonstrating its potential as a skin substitute. Irradiation at 25 kGy caused structural damage to the amnion.
- Oxysterols in adipose tissue-derived mesenchymal stem cell proliferation and death(2017) SILVA, Suelen Feitoza; LEVY, Debora; RUIZ, Jorge Luis Maria; MELO, Thatiana Correa de; ISAAC, Cesar; FIDELIS, Maira Luisa; RODRIGUES, Alessandro; BYDLOWSKI, Sergio PauloMesenchymal stem cells (MSCs) are multipotent cells characterized by self-renewal and cellular differentiation capabilities. Oxysterols comprise a very heterogeneous group derived from cholesterol through enzymatic and non-enzymatic oxidation. Potent effects in cell death processes, including cytoxicity and apoptosis induction, were described in several cell lines. Very little is known about the effects of oxysterols in MSCs. 7-ketocholesterol (7-KC), one of the most important oxysterols, was shown to be cytotoxic to human adipose tissue-derived MSCs. Here, we describe the short-term (24 h) cytotoxic effects of cholestan-3 alpha-5 beta-6 alpha-triol, 3,5 cholestan-7-one, (3 alpha-5 beta-6 alpha)- cholestane-3,6-diol, 7-oxocholest-5-en-3 beta-ylacetate, and 5 beta-6 beta epoxy-cholesterol, on MSCs derived from human adipose tissue. MSCs were isolated from adipose tissue obtained from three young, healthy women. Oxysterols, with the exception of 3,5 cholestan-7-one and 7-oxocholest-5-en-3 beta-yl acetate, led to a complex mode of cell death that include apoptosis, necrosis and autophagy, depending on the type of oxysterol and concentration, being cholestan-3 alpha-5 beta-6 alpha-triol the most effective. Inhibition of proliferation was also promoted by these oxysterols, but no changes in cell cycle were observed.