Theranostic applications: Non-ionizing cellular and molecular imaging through innovative nanosystems for early diagnosis and therapy

Modern medicine is expanding the possibilities of receiving "personalized" diagnosis and therapies,providing minimal invasiveness,technological solutions based on non-ionizing radiation,early detection of pathologies with the main objectives of being operator independent and with low cost to society.Our research activities aim to strongly contribute to these trends by improving the capabilities of current diagnostic imaging systems,which are of key importance in possibly providing both optimal diagnosis and therapies to patients.In medical diagnostics,cellular imaging aims to develop new methods and technologies for the detection of specific metabolic processes in living organisms,in order to accurately identify and discriminate normal from pathological tissues.In fact,most diseases have a "molecular basis" that detected through these new diagnostic methodologies can provide enormous benefits to medicine.Nowadays,this possibility is mainly related to the use of Positron Emission Tomography,with an exposure to ionizing radiation for patients and operators and with extremely high medical diagnosticscosts.The future possible development of non-ionizing cellular imaging based on techniques such as Nuclear Magnetic Resonance or Ultrasound,would represent an important step towards modern and personalized therapies.During the last decade,the field of nanotechnology has made important progress and a wide range of organic and inorganic nanomaterials are now available with an incredible number of further combinations with other compounds for cellular targeting.The availability of these new advanced nanosystems allows new scenarios in diagnostic methodologies which are potentially capable of providing morphological and functional information together with metabolic and cellular indications.     

In vivo tracking of genetically engineered, anti-HER2/neu directed natural killer cells to HER2/neu positive mammary tumors with magnetic resonance imaging

The purpose of this study is to optimize labeling of the human natural killer (NK) cell line NK-92 with iron-oxide-based contrast agents and to monitor the in vivo distribution of genetically engineered NK-92 cells, which are directed against HER2/neu receptors, to HER2/neu positive mammary tumors with magnetic resonance (MR) imaging. Parental NK-92 cells and genetically modified HER2/neu specific NK-92-scFv(FRP5)-zeta cells, expressing a chimeric antigen receptor specific to the tumor-associated ErbB2 (HER2/neu) antigen, were labeled with ferumoxides and ferucarbotran using simple incubation, lipofection and electroporation techniques. Labeling efficiency was evaluated by MR imaging, Prussian blue stains and spectrometry. Subsequently, ferucarbotran-labeled NK-92-scFv(FRP5)-zeta (n=3) or parental NK-92 cells were intravenously injected into the tail vein of six mice with HER2/neu-positive NIH 3T3 mammary tumors, implanted in the mammary fat pad. The accumulation of the cells in the tumors was monitored by MR imaging before and 12 and 24 h after cell injection (p.i.). MR data were correlated with histopathology. Both the parental NK-92 and the genetically modified NK-92-scFv(FRP5)-zeta cells could be labeled with ferucarbotran and ferumoxides by lipofection and electroporation, but not by simple incubation. The intracellular cytoplasmatic iron-oxide uptake was significantly higher after labeling with ferucarbotran than ferumoxides (P<0.05). After intravenous injection of 5×10⁶ NK-92-scFv(FRP5)-zeta cells into tumor-bearing mice, MR showed a progressive signal decline in HER2/neu-positive mammary tumors at 12 and 24 h (p.i.). Conversely, injection of 5×10⁶ parental NK-92 control cells, not directed against HER2/neu receptors, did not cause significant signal intensity changes of the tumors. Histopathology confirmed an accumulation of the former, but not the latter cells in tumor tissue. The human natural killer cell line NK-92 can be efficiently labeled with clinically applicable iron-oxide contrast agents, and the accumulation of these labeled cells in murine tumors can be monitored in vivo with MR imaging. This MR cell tracking technique may be applied to monitor NK-cell based immunotherapies in patients in order to assess the presence and extent of NK-cell tumor accumulations and, thus, to determine therapy response early and non-invasively.     

Comparison of iron oxide labeling properties of hematopoietic progenitor cells from umbilical cord blood and from peripheral blood for subsequent in vivo tracking in a xenotransplant mouse model XXX

RATIONALE AND OBJECTIVES: To compare and optimize ferumoxides labeling of human hematopoietic progenitor cells from umbilical cord blood and from peripheral blood for subsequent in vivo tracking with a clinical 1.5 T MR scanner. MATERIALS AND METHODS: Human hematopoietic progenitor cells, derived from umbilical cord blood or peripheral blood, were labeled with Ferumoxides by simple incubation or lipofection. Cellular iron uptake was quantified with spectrometry. Then, 3 x 10(7)-labeled cells were injected into the tail vein of 12 female nude Balb/c mice. The mice underwent magnetic resonance imaging before and 24 hours after injection. Precontrast and postcontrast signal intensities of liver, spleen, and bone marrow were measured and tested for significant differences with the t-test. Immunostains served as a histopathologic standard of reference. RESULTS: After labeling by simple incubation, only umbilical cord blood cells, but not peripheral blood cells, showed a significant iron uptake and could be tracked in vivo with magnetic resonance imaging. Using lipofection, both cell types could be tracked in vivo. A significant decline in signal intensity was observed in liver, spleen, and bone marrow at 24 hours after injection of efficiently labeled ferumoxides cells (P < .05). Histopathology proved the distribution of iron oxide-labeled cells to these organs. CONCLUSION: Hematopoietic progenitor cells from umbilical cord blood can be labeled by simple incubation with an Food and Drug Administration-approved magnetic resonance contrast agent with sufficient efficiency to provide an in vivo cell tracking at 1.5 T. Progenitor cells from peripheral blood need to be labeled with adjunctive transfection techniques to be depicted in vivo at 1.5 T.     

64层CT灌注成像早期诊断放射性肺损伤的临床价值

目的 探讨64层CT灌注成像(CTPI)早期诊断放射性肺损伤(RILI)的临床价值.方法 48例接受术后放疗的上段食管癌患者(照射总剂量均为60Gy),放疗前及放疗1/2总剂量时间点(30 Gy)行CTPI检查,同期检测外周血中肿瘤坏死因子(TNF-α)、转化生长因子(TGF-β1),分析发生RILI(A组)与未发生RILI(B组)患者的血清细胞因子、常规CT表现及CTPI灌注值[相对血流量(rrBF)、相对血容量(rrBV)、相对毛细血管通透性(rrPS)]的变化,采用随机区组设计t检验比较两组间血清细胞因子、CTPI灌注值的差异,采用x2检验比较常规CT与CTPI对RILI检出的差异.结果 48例患者中,18例发生RILI(A组).A组放疗前外周血TNF-α和TGF-β1分别为(36.1±15.0) ng/L、(17.5±9.8)μg/L,放疗后分别为(30.4±14.9) ng/L、(14.3±7.6) μg/L,放疗前后的差异无统计学意义(t值分别为1.14、1.10,尸值分别为0.264、0.279).放疗1/2总剂量时,A、B两组的外周血TNF-α分别为(30.4±14.9)、(28.9±14.7)ng/L,TGF-β1分别为(14.3±7.6)、(14.4±6.0) μg/L,两组间差异无统计学意义(t值分别为0.33、1.23,P值分别为0.746、0.227);但A组常规CT图像上有2例出现阳性征象.受照射肺组织rrBF、rrBV、rrPS照射前,A组分别为1.01±0.13、1.01±0.07、1.03±0.15,B组分别为1.01±0.09、1.00±0.12、1.01±0.17;照射后,A组分别为1.32±0.19、1.30±0.20、1.38±0.20,B组分别为1.20±0.14、1.21±0.09、1.06±0.16.A组受照射肺组织rrBF、rrBV、rrPS均较照射前显著增高,差异有统计学意义(t值分别为5.67、5.97、6.11,P值均为0.000);B组的rrBF、rrBV较照射前有增高,差异有统计学意义(t值分别为6.52、7.84,P值均为0.000),rrPS无明显变化,差异无统计学意义(t=1.36,P =0.178);照射后A、B两组rrBF、rrBV、rrPS间差异均有统计学意义(t值分别为2.32、2.18、6.04,P值分别为0.025、0.034、0.000).根据ROC曲线,设rrPS=1.28为阈值,诊断RILI的敏感度、特异度分别为77.8％、93.3％,高于常规CT的11.1％、90.0％,两者差异有统计学意义(x2=13.61,P=0.000).结论 外周血中TNF-α、TGF-β1变化对早期检测肿瘤放疗患者RILI的价值尚不确定.CTPI可反映放疗后肺组织血液动力学的变化,可早期反映RILI患者照射野的灌注异常,有可能早期检出RILI.