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Neuro Oncol. 2016 May;18(5):691-9. doi: 10.1093/neuonc/nov263. Epub 2015 Oct 31.

MRI contrast agent for targeting glioma: interleukin-13 labeled liposome encapsulating gadolinium-DTPA.

Author information

1
Department of Neurosurgery, Pennsylvania State University College of Medicine, Hershey, Pennsylvania (X.L., A.B.M., K.A.D., E.R., B.S.-W., J.M.S., J.R.C., Q.X.Y.); Department of Radiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania (X.L., P.A.M., Q.X.Y.); Department of Microbiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania (S.H.).

Abstract

BACKGROUND:

Detection of glioma with MRI contrast agent is limited to cases in which the blood-brain barrier (BBB) is compromised as contrast agents cannot cross the BBB. Thus, an early-stage infiltrating tumor is not detectable. Interleukin-13 receptor alpha 2 (IL-13Rα2), which has been shown to be overexpressed in glioma, can be used as a target moiety. We hypothesized that liposomes conjugated with IL-13 and encapsulating MRI contrast agent are capable of passing through an intact BBB and producing MRI contrast with greater sensitivity.

METHODS:

The targeted MRI contrast agent was created by encapsulating Magnevist (Gd-DTPA) into liposomes conjugated with IL-13 and characterized by particle size distribution, cytotoxicity, and MRI relaxivity. MR image intensity was evaluated in the brain in normal mice post injection of Gd-DTPA and IL-13-liposome-Gd-DTPA one day apart. The specificity for glioma detection by IL-13-liposome-Gd-DTPA was demonstrated in an intracranial glioma mouse model and validated histologically.

RESULTS:

The average size of IL-13-liposome-Gd-DTPA was 137 ± 43 nm with relaxivity of 4.0 ± 0.4 L/mmole-s at 7 Tesla. No significant cytotoxicity was observed with MTS assay and serum chemistry in mice. The MRI signal intensity was enhanced up to 15% post injection of IL-13-liposome-Gd-DTPA in normal brain tissue following a similar time course as that for the pituitary gland outside of the BBB. MRI enhanced by IL-13-liposome-Gd-DTPA detected small tumor masses in addition to those seen with Magnevist-enhanced MRI.

CONCLUSIONS:

IL-13-liposome-Gd-DTPA is able to pass through the uncompromised BBB and detect an early stage glioma that cannot be seen with conventional contrast-enhanced MRI.

KEYWORDS:

IL-13; blood-brain barrier (BBB); glioma; liposome; targeted MRI contrast agent

PMID:
26519740
PMCID:
PMC4827043
DOI:
10.1093/neuonc/nov263
[Indexed for MEDLINE]
Free PMC Article

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