Self-assembling nanocomplexes by combining ferumoxytol, heparin and protamine for cell tracking by magnetic resonance imaging

Nat Med. 2012 Feb 26;18(3):463-7. doi: 10.1038/nm.2666.

Abstract

We report on a new straightforward magnetic cell-labeling approach that combines three US Food and Drug Administration (FDA)-approved drugs--ferumoxytol, heparin and protamine--in serum-free medium to form self-assembling nanocomplexes that effectively label cells for in vivo magnetic resonance imaging (MRI). We observed that the ferumoxytol-heparin-protamine (HPF) nanocomplexes were stable in serum-free cell culture medium. HPF nanocomplexes show a threefold increase in T2 relaxivity compared to ferumoxytol. Electron microscopy showed internalized HPF in endosomes, which we confirmed by Prussian blue staining of labeled cells. There was no long-term effect or toxicity on cellular physiology or function of HPF-labeled hematopoietic stem cells, bone marrow stromal cells, neural stem cells or T cells when compared to controls. In vivo MRI detected 1,000 HPF-labeled cells implanted in rat brains. This HPF labeling method should facilitate the monitoring by MRI of infused or implanted cells in clinical trials.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Bone Marrow Cells / cytology
  • Brain / cytology*
  • Brain / diagnostic imaging
  • Brain / ultrastructure
  • Cell Differentiation / drug effects
  • Cell Tracking / methods*
  • Clinical Trials as Topic
  • Culture Media, Serum-Free
  • Endosomes / ultrastructure
  • Ferrosoferric Oxide / administration & dosage
  • Ferrosoferric Oxide / adverse effects
  • Ferrosoferric Oxide / chemistry*
  • Hematopoietic Stem Cells / cytology
  • Heparin / administration & dosage
  • Heparin / adverse effects
  • Heparin / chemistry*
  • Humans
  • Magnetic Resonance Imaging
  • Magnetite Nanoparticles / administration & dosage*
  • Magnetite Nanoparticles / adverse effects*
  • Magnetite Nanoparticles / chemistry*
  • Magnetite Nanoparticles / ultrastructure
  • Male
  • Mesenchymal Stem Cells / cytology
  • Microscopy, Electron
  • Neurons / cytology
  • Protamines / administration & dosage
  • Protamines / adverse effects
  • Protamines / chemistry*
  • Radiography
  • Rats
  • Stem Cell Transplantation
  • Stromal Cells / cytology
  • T-Lymphocytes / cytology

Substances

  • Culture Media, Serum-Free
  • Magnetite Nanoparticles
  • Protamines
  • Heparin
  • Ferrosoferric Oxide