To assess a novel cell manipulation technique of tissue engineering with respect to its ability to augment superparamagnetic iron oxide particles （SPIO） labeled mesenchymal stem cells （MSCs） density at a localized...To assess a novel cell manipulation technique of tissue engineering with respect to its ability to augment superparamagnetic iron oxide particles （SPIO） labeled mesenchymal stem cells （MSCs） density at a localized cartilage defect site in an in vitro phantom by applying magnetic force. Meanwhile, non-invasive imaging techniques were use to track SPIO-labeled MSCs by magnetic resonance imaging （MRI）. Human bone marrow MSCs were cultured and labeled with SPIO. Fresh degenerated human osteochondral fragments were obtained during total knee arthroplasty and a cartilage defect was created at the center. Then, the osteochondral fragments were attached to the sidewalls of culture flasks filled with phosphate-buffered saline （PBS） to mimic the human joint cavity. The SPIO-labeled MSCs were injected into the culture flasks in the presence of a 0.57 Tesla （T） magnetic force. Before and 90 min after cell targeting, the specimens underwent T2-weighted turbo spin-echo （SET2WI） sequence of 3.0 T MRI. MRI results were compared with histological findings. Macroscopic observation showed that SPIO-labeled MSCs were steered to the target region of cartilage defect. MRI revealed significant changes in signal intensity （P0.01）. HE staining exibited that a great number of MSCs formed a three-dimensional （3D） cell ＂sheet＂ structure at the chondral defect site. It was concluded that 0.57 T magnetic force permits spatial delivery of magnetically labeled MSCs to the target region in vitro. High-field MRI can serve as an very sensitive non-invasive technique for the visualization of SPIO-labeled MSCs.展开更多
Background Angiogenesis is an essential step for tumor development and metastasis.The cell adhesion molecule αvβ3 integrin plays an important role in angiogenesis and is a specific marker of tumor angiogenesis.A nov...Background Angiogenesis is an essential step for tumor development and metastasis.The cell adhesion molecule αvβ3 integrin plays an important role in angiogenesis and is a specific marker of tumor angiogenesis.A novel αvβ3 integrintargeted magnetic resonance （MR） imaging contrast agent utilizing Arg-Gly-Asp （RGD） and ultrasmall superparamagnetic iron oxide particles （USPIO） （referred to as RGD-USPIO） was designed and its uptake by endothelial cells was assessed both in vitro and in vivo to evaluate the angiogenic profile of lung cancer.Methods USPIO were coated with-NH3＋ and conjugated with RGD peptides.Prussian blue staining was performed to evaluate the specific uptake of RGD-USPIO by human umbilical vein endothelial cells （HUVECs）.Targeted uptake and subcellular localization of RGD-USPIO in HUVECs were confirmed by transmission electron microscopy （TEM）.The ability of RGD-USPIO to noninvasively assess αvβ3 integrin positive vessels in lung adenocarcinoma A549 tumor xenografts was evaluated with a 4.7T MR scanner.Immunohistochemistry was used to detect αvβ3 integrin expression and vessel distribution in A549 tumor xenografts.Results HUVECs internalized RGD-USPIO significantly more than plain USPIO.The uptake of RGD-USPIO by HUVECs could be competitively inhibited by addition of free RGD.A significant decrease in T2 signal intensity （SI） was observed at the periphery of A549 tumor xenografts at 30 minutes （P 〈0.05） and 2 hours （P 〈0.01） after RGD-USPIO was injected via the tail vein.Angiogenic blood vessels were mainly distributed in the periphery of tumor xenografts with positive αvβ3 integrin expression.Conclusions RGD-USPIO could specifically label αvβ3 integrin and be taken up by HUVECs.This molecular MR imaging contrast agent can specifically evaluate the angiogenic profile of lung cancer using a 4.7T MR scanner.展开更多
目的观察血管内皮生长因子C(VEGF-C)抗体与超顺磁性氧化铁颗粒(USPIO)连接的靶向分子探针(VEGF-C-USPIO)在大鼠肝细胞癌(HCC)模型体内的MR成像特点,并探讨其临床意义。方法采用诱导法建立大鼠原位肝癌模型,将30只SD大鼠随机分为实验组(n...目的观察血管内皮生长因子C(VEGF-C)抗体与超顺磁性氧化铁颗粒(USPIO)连接的靶向分子探针(VEGF-C-USPIO)在大鼠肝细胞癌(HCC)模型体内的MR成像特点,并探讨其临床意义。方法采用诱导法建立大鼠原位肝癌模型,将30只SD大鼠随机分为实验组(n=20)和对照组(n=10)。分别于鼠尾静脉注射靶向探针VEGF-C-USPIO和非靶向探针USPIO,并于注射前及注射后1 h对大鼠行MR扫描成像,测量其肝脏肿瘤与周围肝组织的T2WI信号强度,计算噪声比(CNR),比较增强前后2组之间CNR的差异。扫描结束后取动物肝脏进行HE染色明确大鼠肝癌病理类型;普鲁士蓝染色验证肿瘤组织细胞中铁含量;免疫组化染色验证肝癌组织中VEGF-C的表达情况。实验组与对照组间的比较采用独立样本t检验,实验组或对照组内注射对比剂前后的比较采用配对样本t检验。结果 30只大鼠全部诱癌成功,病理学诊断为HCC,成瘤率100%。实验组注射靶向对比剂VEGF-C-USPIO后1 h与注射前CNR比较,差异有统计学意义(2.11±0.23 vs 3.47±0.45,t=-13.15,P<0.001);对照组注射非靶向对比剂USPIO后1 h与注射前CNR之间差异无统计学意义(3.51±0.14 vs 3.82±0.61,t=-1.40,P=0.192);2组大鼠注射对比剂后的CNR比较,差异有统计学意义(t=17.60,P<0.001)。对大鼠肝脏标本行HE染色,结果证实为HCC;免疫组化染色显示,VEGF-C主要在肝癌细胞胞膜及胞浆中表达;普鲁士蓝染色显示,实验组肿瘤组织内蓝染铁颗粒较对照组明显增多。结论所合成的分子靶向探针VEGF-C-USPIO对大鼠HCC模型具有较好的主动靶向作用,能够通过MR信号强度的变化实现HCC的特异性成像,为HCC的早期诊断提供影像学依据。展开更多
基金supported by a grant from the National Natural Sciences Foundation of China (No. 30870639)
文摘To assess a novel cell manipulation technique of tissue engineering with respect to its ability to augment superparamagnetic iron oxide particles （SPIO） labeled mesenchymal stem cells （MSCs） density at a localized cartilage defect site in an in vitro phantom by applying magnetic force. Meanwhile, non-invasive imaging techniques were use to track SPIO-labeled MSCs by magnetic resonance imaging （MRI）. Human bone marrow MSCs were cultured and labeled with SPIO. Fresh degenerated human osteochondral fragments were obtained during total knee arthroplasty and a cartilage defect was created at the center. Then, the osteochondral fragments were attached to the sidewalls of culture flasks filled with phosphate-buffered saline （PBS） to mimic the human joint cavity. The SPIO-labeled MSCs were injected into the culture flasks in the presence of a 0.57 Tesla （T） magnetic force. Before and 90 min after cell targeting, the specimens underwent T2-weighted turbo spin-echo （SET2WI） sequence of 3.0 T MRI. MRI results were compared with histological findings. Macroscopic observation showed that SPIO-labeled MSCs were steered to the target region of cartilage defect. MRI revealed significant changes in signal intensity （P0.01）. HE staining exibited that a great number of MSCs formed a three-dimensional （3D） cell ＂sheet＂ structure at the chondral defect site. It was concluded that 0.57 T magnetic force permits spatial delivery of magnetically labeled MSCs to the target region in vitro. High-field MRI can serve as an very sensitive non-invasive technique for the visualization of SPIO-labeled MSCs.
文摘Background Angiogenesis is an essential step for tumor development and metastasis.The cell adhesion molecule αvβ3 integrin plays an important role in angiogenesis and is a specific marker of tumor angiogenesis.A novel αvβ3 integrintargeted magnetic resonance （MR） imaging contrast agent utilizing Arg-Gly-Asp （RGD） and ultrasmall superparamagnetic iron oxide particles （USPIO） （referred to as RGD-USPIO） was designed and its uptake by endothelial cells was assessed both in vitro and in vivo to evaluate the angiogenic profile of lung cancer.Methods USPIO were coated with-NH3＋ and conjugated with RGD peptides.Prussian blue staining was performed to evaluate the specific uptake of RGD-USPIO by human umbilical vein endothelial cells （HUVECs）.Targeted uptake and subcellular localization of RGD-USPIO in HUVECs were confirmed by transmission electron microscopy （TEM）.The ability of RGD-USPIO to noninvasively assess αvβ3 integrin positive vessels in lung adenocarcinoma A549 tumor xenografts was evaluated with a 4.7T MR scanner.Immunohistochemistry was used to detect αvβ3 integrin expression and vessel distribution in A549 tumor xenografts.Results HUVECs internalized RGD-USPIO significantly more than plain USPIO.The uptake of RGD-USPIO by HUVECs could be competitively inhibited by addition of free RGD.A significant decrease in T2 signal intensity （SI） was observed at the periphery of A549 tumor xenografts at 30 minutes （P 〈0.05） and 2 hours （P 〈0.01） after RGD-USPIO was injected via the tail vein.Angiogenic blood vessels were mainly distributed in the periphery of tumor xenografts with positive αvβ3 integrin expression.Conclusions RGD-USPIO could specifically label αvβ3 integrin and be taken up by HUVECs.This molecular MR imaging contrast agent can specifically evaluate the angiogenic profile of lung cancer using a 4.7T MR scanner.
文摘目的观察血管内皮生长因子C(VEGF-C)抗体与超顺磁性氧化铁颗粒(USPIO)连接的靶向分子探针(VEGF-C-USPIO)在大鼠肝细胞癌(HCC)模型体内的MR成像特点,并探讨其临床意义。方法采用诱导法建立大鼠原位肝癌模型,将30只SD大鼠随机分为实验组(n=20)和对照组(n=10)。分别于鼠尾静脉注射靶向探针VEGF-C-USPIO和非靶向探针USPIO,并于注射前及注射后1 h对大鼠行MR扫描成像,测量其肝脏肿瘤与周围肝组织的T2WI信号强度,计算噪声比(CNR),比较增强前后2组之间CNR的差异。扫描结束后取动物肝脏进行HE染色明确大鼠肝癌病理类型;普鲁士蓝染色验证肿瘤组织细胞中铁含量;免疫组化染色验证肝癌组织中VEGF-C的表达情况。实验组与对照组间的比较采用独立样本t检验,实验组或对照组内注射对比剂前后的比较采用配对样本t检验。结果 30只大鼠全部诱癌成功,病理学诊断为HCC,成瘤率100%。实验组注射靶向对比剂VEGF-C-USPIO后1 h与注射前CNR比较,差异有统计学意义(2.11±0.23 vs 3.47±0.45,t=-13.15,P<0.001);对照组注射非靶向对比剂USPIO后1 h与注射前CNR之间差异无统计学意义(3.51±0.14 vs 3.82±0.61,t=-1.40,P=0.192);2组大鼠注射对比剂后的CNR比较,差异有统计学意义(t=17.60,P<0.001)。对大鼠肝脏标本行HE染色,结果证实为HCC;免疫组化染色显示,VEGF-C主要在肝癌细胞胞膜及胞浆中表达;普鲁士蓝染色显示,实验组肿瘤组织内蓝染铁颗粒较对照组明显增多。结论所合成的分子靶向探针VEGF-C-USPIO对大鼠HCC模型具有较好的主动靶向作用,能够通过MR信号强度的变化实现HCC的特异性成像,为HCC的早期诊断提供影像学依据。
