Enxerto de gordura em modelo de neoplasia mamária residual em camundongos.
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Data
2018-04-30
Autores
Silva, Mayara Mytzi de Aquino [UNIFESP]
Orientadores
Sabino Neto, Miguel [UNIFESP]
Tipo
Tese de doutorado
Título da Revista
ISSN da Revista
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Resumo
Introdução: O enxerto de gordura vem sendo amplamente usado na
reconstrução de mama sem evidência clínica de risco oncológico. Entretanto,
as células-tronco do tecido adiposo vêm demonstrando em vários estudos in
vitro e in vivo capacidade de promover crescimento e disseminação tumoral
do câncer de mama. Objetivo: Avaliar o impacto da lipoenxertia sobre
características macroscópicas e microscópicas de tumores em modelo
experimental de neoplasia mamária residual em camundongos. Método: 40
camundongos-fêmea NOD-SCID gamma receberam xenoenxerto de 1000
células MCF7 em quatro sítios de glândulas mamárias. Após duas semanas,
lipoaspirado humano preparado conforme técnica de Coleman (n=20, grupo
lipo) ou solução salina estéril (N=20, grupo salina) foram injetados nos sítios
tumorais. Em oito semanas, os tumores foram avaliados quanto a volume,
massa, grau histológico, índice de Ki67 e ocorrência de metástases em
fígado, pulmão e baço. Resultados: Todos os sítios enxertados com células
neoplásicas formaram tumores e todos os enxertos de gordura integraram e
foram detectados adjacentes aos tumores ao final do seguimento. Tumores
de animais do grupo lipo apresentaram significantemente menor volume
(p=0,046), menor massa (p=0,038) e menor proliferação medida pelo índice
de Ki67 (p=0,01) que os do grupo salina. O índice histológico foi o mesmo
em ambos os grupos e não foram detectadas metástases nos órgãos
analisados. Conclusão: A lipoenxertia num modelo animal de tumor residual
em camundongos não promoveu impacto negativo nas características
macroscópicas e microscópicas do câncer de mama.
Introduction: Autologous fat grafting is becoming widely used for breast reconstruction with no evidence of increased oncologic risk. However, the bioactive adipose stromal cells have been shown in many in vitro and animal studies to promote cancer cell growth and dissemination. Objective: Assess the impact of fat grafting on macroscopic and microscopic features of tumors in a clinically relevant animal model of residual breast cancer. Methods: 40 female NOD-SCID gamma mice were injected with 1K MCF7 breast cancer cells in four sites of mammary fat pads. After tumor engraftment in two weeks, injections of human lipoaspirate prepared according to Coleman’s technique (N=20, lipo group) or sterile saline (N=20, saline group) were performed at tumor sites. In eight weeks, tumors were assessed for volume, mass, histological grade, Ki67 positivity index and metastatic spread. Results: All sites injected with breast cancer cells formed macroscopic tumors and all fat grafts were retained and collocated with breast cancer at the end of follow-up. Tumors from animals in the lipo group presented significantly lower volume (p=0.046), lower mass (p=0.038) and lower Ki67 proliferation index assessed by Ki67 positivity (p=0.01) compared to the saline group. Histological grade was the same for both groups and no metastatic lesion was identified in lung, liver or spleen of any animal. Conclusion: Fat grafting performed in the setting of residual breast tumor in an animal model did not cause any worsening in macroscopic or microscopic features of breast cancer.
Introduction: Autologous fat grafting is becoming widely used for breast reconstruction with no evidence of increased oncologic risk. However, the bioactive adipose stromal cells have been shown in many in vitro and animal studies to promote cancer cell growth and dissemination. Objective: Assess the impact of fat grafting on macroscopic and microscopic features of tumors in a clinically relevant animal model of residual breast cancer. Methods: 40 female NOD-SCID gamma mice were injected with 1K MCF7 breast cancer cells in four sites of mammary fat pads. After tumor engraftment in two weeks, injections of human lipoaspirate prepared according to Coleman’s technique (N=20, lipo group) or sterile saline (N=20, saline group) were performed at tumor sites. In eight weeks, tumors were assessed for volume, mass, histological grade, Ki67 positivity index and metastatic spread. Results: All sites injected with breast cancer cells formed macroscopic tumors and all fat grafts were retained and collocated with breast cancer at the end of follow-up. Tumors from animals in the lipo group presented significantly lower volume (p=0.046), lower mass (p=0.038) and lower Ki67 proliferation index assessed by Ki67 positivity (p=0.01) compared to the saline group. Histological grade was the same for both groups and no metastatic lesion was identified in lung, liver or spleen of any animal. Conclusion: Fat grafting performed in the setting of residual breast tumor in an animal model did not cause any worsening in macroscopic or microscopic features of breast cancer.
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Citação
SILVA, Mayara Mytzi de Aquino. Enxerto de gordura em modelo de neoplasia mamária residual em camundongos. 2018. 156 f. Tese (Doutorado em Cirurgia Translacional) – Escola Paulista de Medicina. Universidade Federal de São Paulo, São Paulo, 2018.