RESUMEN
Peripheral arterial disease is a clinical problem in which mesenchymal stromal cell (MSC) transplantation may offer substantial benefit by promoting the generation of new blood vessels and improving limb ischemia and wound healing via their potent paracrine activities. MRI allows for the noninvasive tracking of cells over time using iron oxide contrast agents to label cells before they are injected or transplanted. However, a major limitation of the tracking of iron oxide-labeled cells with MRI is the possibility that dead or dying cells will transfer the iron oxide label to local bystander macrophages, making it very difficult to distinguish between viable transplanted cells and endogenous macrophages in the images. In this study, a severely immune-compromised mouse, with limited macrophage activity, was investigated to examine cell tracking in a system in which bystander cell uptake of dead, iron-labeled cells or free iron particles was minimized. MRI was used to track the fate of MSCs over 21 days after their intramuscular transplantation in mice with a femoral artery ligation. In all mice, a region of signal loss was observed at the injection site and the volume of signal hypointensity diminished over time. Fluorescence and light microscopy showed that iron-positive MSCs persisted at the transplant site and often appeared to be integrated in perivascular niches. This was compared with MSC transplantation in immune-competent mice with femoral artery ligation. In these mice, the regions of signal loss caused by iron-labeled MSC cleared more slowly, and histology revealed iron particles trapped at the site of cell transplantation and associated with areas of inflammation.
Asunto(s)
Extremidades/irrigación sanguínea , Huésped Inmunocomprometido , Hierro/metabolismo , Isquemia/terapia , Imagen por Resonancia Magnética , Trasplante de Células Madre Mesenquimatosas , Células Madre Mesenquimatosas/citología , Animales , Supervivencia Celular , Rastreo Celular , Modelos Animales de Enfermedad , Extremidades/patología , Citometría de Flujo , Inyecciones Intramusculares , Subunidad gamma Común de Receptores de Interleucina/metabolismo , Isquemia/patología , Masculino , Células Madre Mesenquimatosas/metabolismo , Ratones Endogámicos C57BL , Ratones Endogámicos NOD , Ratones SCID , Coloración y EtiquetadoRESUMEN
BACKGROUND AIMS. The use of dendritic cells (DC) as an adjuvant in cell-based immunotherapeutic cancer vaccines is a growing field of interest. A reliable and non-invasive method to track the fate of autologous DC following their administration to patients is required in order to confirm that clinically sufficient numbers are reaching the lymph node (LN). We demonstrate that an immunocompromised mouse model can be used to conduct translational studies employing cellular magnetic resonance imaging (MRI). Such studies can provide clinically relevant information regarding the migration potential of clinical-grade DC used in cancer immunotherapies. METHODS. Human monocyte-derived dendritic cells (mo-DC) were generated from negatively selected monocytes obtained from either healthy donors or cancer patients. DC were labeled with superparamagnetic iron oxide (SPIO) nanoparticles in order to track them in vivo in a CB17scid mouse model using cellular MRI. SPIO did not have any adverse effects on DC phenotype or function, independent of donor type. Cellular MRI readily detected migration of SPIO-loaded DC in CB17scid mice. No differences in migration were observed between DC obtained from healthy donors and those obtained from donors undergoing autologous stem cell transplant for cancer therapy. CONCLUSIONS. Cellular MRI provided semi-quantitative image data that corresponded with data obtained by digital morphometry, validating cellular MRI's potential to assess DC migration in DC-based cancer immunotherapy clinical trials.
Asunto(s)
Vacunas contra el Cáncer , Movimiento Celular , Células Dendríticas/metabolismo , Inmunoterapia Adoptiva , Neoplasias/terapia , Animales , Antígenos de Diferenciación/metabolismo , Células Cultivadas , Células Dendríticas/citología , Células Dendríticas/trasplante , Modelos Animales de Enfermedad , Estudios de Factibilidad , Humanos , Imagen por Resonancia Magnética/métodos , Ratones , Ratones SCID , Monocitos/citología , Neoplasias/inmunología , Neoplasias/patologíaRESUMEN
SCOPE: Hepatic LDL receptor (LDLR) and proprotein convertase subtilisin/kexin type 9 (PCSK9) regulate the clearance of plasma LDL-cholesterol (LDL-C): LDLR promotes it, and PCSK9 opposes it. These proteins also express in pancreatic ß cells. Using cultured hepatocytes, we previously showed that the plant flavonoid quercetin-3-glucoside (Q3G) inhibits PCSK9 secretion, stimulated LDLR expression, and enhanced LDL-C uptake. Here, we examine whether Q3G supplementation could reverse the hyperlipidemia and hyperinsulinemia of mice fed a high-cholesterol diet, and how it affects hepatic and pancreatic LDLR and PCSK9 expression. METHODS AND RESULTS: For 12 weeks, mice are fed a low- (0%) or high- (1%) cholesterol diet (LCD or HCD), supplemented or not with Q3G at 0.05 or 0.1% (w/w). Tissue LDLR and PCSK9 is analyzed by immunoblotting, plasma PCSK9 and insulin by ELISA, and plasma cholesterol and glucose by colorimetry. In LCD-fed mice, Q3G has no effect. In HCD-fed mice, it attenuates the increase in plasma cholesterol and insulin, accentuates the decrease in plasma PCSK9, and increases hepatic and pancreatic LDLR and PCSK9. In cultured pancreatic ß cells, however, it stimulates PCSK9 secretion. CONCLUSION: In mice, dietary Q3G could counter HCD-induced hyperlipidemia and hyperinsulinemia, in part by oppositely modulating hepatic and pancreatic PCSK9 secretion.
Asunto(s)
Hiperlipidemias/prevención & control , Hipolipemiantes/uso terapéutico , Hígado/metabolismo , Páncreas/metabolismo , Proproteína Convertasa 9/metabolismo , Quercetina/análogos & derivados , Receptores de LDL/metabolismo , Animales , Línea Celular Tumoral , Colesterol en la Dieta/efectos adversos , Suplementos Dietéticos/efectos adversos , Regulación de la Expresión Génica , Transportador de Glucosa de Tipo 2/agonistas , Transportador de Glucosa de Tipo 2/antagonistas & inhibidores , Transportador de Glucosa de Tipo 2/genética , Transportador de Glucosa de Tipo 2/metabolismo , Hiperinsulinismo/sangre , Hiperinsulinismo/metabolismo , Hiperinsulinismo/patología , Hiperinsulinismo/prevención & control , Hiperlipidemias/sangre , Hiperlipidemias/metabolismo , Hiperlipidemias/patología , Hipolipemiantes/administración & dosificación , Hipolipemiantes/efectos adversos , Resistencia a la Insulina , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patología , Hígado/patología , Masculino , Ratones Endogámicos C57BL , Enfermedad del Hígado Graso no Alcohólico/sangre , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Enfermedad del Hígado Graso no Alcohólico/patología , Enfermedad del Hígado Graso no Alcohólico/prevención & control , Especificidad de Órganos , Páncreas/patología , Proproteína Convertasa 9/sangre , Proproteína Convertasa 9/genética , Quercetina/administración & dosificación , Quercetina/efectos adversos , Quercetina/uso terapéutico , Receptores de LDL/genéticaRESUMEN
The goal of this study was to investigate the normal MRI appearance of lymphoid organs in immuno-competent and immuno-deficient mice commonly used in research. Four mice from each of four different mouse strains (nude, NOG, C57BL/6, CB-17 SCID (SCID)) were imaged weekly for one month. Images were acquired with a 3D balanced steady state free precession (bSSFP) sequence. The volume of the lymph nodes and spleens were measured from MR images. In images of nude and SCID mice, lymph nodes sometimes contained a hyperintense region visible on MRI images. Volumes of the nodes were highly variable in nude mice. Nodes in SCID mice were smaller than in nude or C57Bl/6 mice (p<0.0001). Lymph node volumes changed slightly over time in all strains. The spleens of C57Bl/6 and nude mice were similar in size and appearance. Spleens of SCID and NOG mice were significantly smaller (p<0.0001) and abnormal in appearance. The MRI appearance of the normal lymph nodes and spleen varies considerably in the various mouse strains examined in this study. This is important to recognize in order to avoid the misinterpretation of MRI findings as abnormal when these strains are used in MRI imaging studies.