title: The synthesis of a D-glucosamine contrast agent, Gd-DTPA-DG, and its application in cancer molecular imaging with MRI.
abstract: OBJECTIVE
  The purpose of this study is to describe the synthesis of Gadolinium-diethylenetriamine pentaacetic acid-deoxyglucosamine (Gd-DTPA-DG) which is a d-glucosamine metabolic MR imaging contrast agent. We will also discuss its use in a pilot MRI study using a xenograft mouse model of human adenocarcinoma.
  
  
  METHODS
  This novel contrast agent was specifically studied because of its ability to "target" metabolically active tumor tissues. In this study Gd-DTPA-DG is used to investigate how tumor tissues would react to a dose of 0.2 mmol Gd/kg over a 120 min exposure in a xenograft mouse model. These experiments used athymic mice implanted with human pulmonary adenocarcinoma (A549) as demonstrated by dynamic MRI. Alternately, another contrast agent that is not specific for targeting, Gd-DTPA, was used as the control at a similar dose of gadolinium. Efficacy of the targeted contrast agent was assessed by measuring relaxation rate in vitro and signal intensity (SI) in vivo. Statistical differences were calculated using one-way analysis of variance.
  
  
  RESULTS
  The synthesized Gd-DTPA-DG was shown to improve the contrast of tumor tissue in this model. Gd-DTPA-DG was also shown to have a similar pharmacokinetic rate but generated a higher relaxation rate in tumor tissues relative to the control contrast Gd-DTPA. In comparison to the pre-contrast imaging, the SI of tumor tissue in the experimental group was shown to be significantly increased at 15 min after injection of Gd-DTPA-DG (p<0.001). The enhanced signal intensity spread from the edge of the tumor to the center and seemed to strengthen the idea that MRI performance would be useful in different tumor tissues.
  
  
  CONCLUSIONS
  This preliminary study shows that this new chelated contrast agent, Gd-DTPA-DG, can be specifically targeted to accumulation in tumor tissue as compared to normal tissues. This targeted paramagnetic contrast agent has potential for specific cancer molecular imaging with MRI.
authors.affiliation: Department of Nuclear Medicine, Affiliated Hospital of Luzhou Medical College, Luzhou, Sichuan 646000, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Yue
authors.initials: Y
authors.lastname: Chen
authors.forename: Da Jing
authors.initials: DJ
authors.lastname: Guo
authors.forename: Zhan Wen
authors.initials: ZW
authors.lastname: Huang
authors.forename: Liang
authors.initials: L
authors.lastname: Cai
authors.forename: Ling
authors.initials: L
authors.lastname: He
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism*; D000704:Analysis of Variance; D000818:Animals; D003287:Contrast Media / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D019786:Gadolinium DTPA / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D005944:Glucosamine / Q000737:chemistry* / Q000493:pharmacokinetics; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D008819:Mice, Nude; D009374:Neoplasms, Experimental / Q000378:metabolism*; D014183:Transplantation, Heterologous
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA; D005944:Glucosamine