Dimethyl sulfoxide (DMSO) as a potential contrast agent for brain tumors

Area of Science:

• Neuroscience
• Oncology
• Radiology

Background:

• Dimethyl sulfoxide (DMSO) is a common solvent for chemotherapeutics in preclinical glioma models.
• DMSO administration revealed unexpected signals in mouse brain MRI, prompting further investigation.

Purpose of the Study:

• To investigate the accumulation and wash-out kinetics of DMSO in normal brain parenchyma and GL261 glioblastomas (GBMs) using Magnetic Resonance Spectroscopy (MRS) and Spectroscopic Imaging (MRSI).
• To evaluate DMSO's potential as a contrast agent for brain tumor detection and monitoring.

Main Methods:

• Single-voxel MRS and MRSI were employed to quantify DMSO concentrations and their time-course in control mice, GBMs, and oligodendrogliomas (ODs).
• Pharmacokinetic parameters, including accumulation and half-life, were determined for DMSO in different brain tissues.
• Blood-brain barrier permeability was assessed by observing T(1) contrast enhancement post-gadolinium administration.

Main Results:

• DMSO accumulated significantly higher in GBMs (6.18 ± 0.85 µmol/g water) compared to normal brain (p<0.05).
• DMSO exhibited differential wash-out kinetics: half-lives were 2.06 ± 0.58 h in normal brain and 4.57 ± 1.15 h in GBMs.
• MRSI revealed hotspots of DMSO accumulation within tumors, and similar patterns were observed in ODs.
• DMSO crossed the intact blood-brain barrier in normal brain and ODs, as indicated by the lack of T(1) enhancement.

Conclusions:

• DMSO demonstrates distinct accumulation and wash-out characteristics in brain tumors versus normal brain tissue.
• DMSO shows promise as a novel MRI contrast agent for detecting brain tumors, including those not visible with standard gadolinium contrast.
• DMSO may aid in monitoring tumor progression and therapeutic responses by revealing spatial heterogeneities.