Related Experiment Video
Updated: May 31, 2026
06:58
Synthesis of an In vivo MRI-detectable Apoptosis Probe
Published on: July 31, 2012
Quantitative magnetization transfer studies of apoptotic cell death
Colleen Bailey1, Kimberly L Desmond, Gregory J Czarnota
1Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada. colleen.bailey@sri.utoronto.ca
Magnetic Resonance in Medicine
|June 23, 2011
Summary
Magnetization transfer (MT) measurements reveal subtle changes in late-stage apoptosis of acute myeloid leukemia cells. Quantitative parameters, not the MT ratio, indicated alterations in macromolecular protons and water relaxation.
Area of Science:
- Biophysics
- Cell Biology
- Medical Imaging
Background:
- Apoptosis is a critical process in cancer development and treatment.
- Magnetization transfer (MT) is a promising MRI technique for probing molecular environments.
- Understanding cellular changes during apoptosis is crucial for effective cancer therapy.
Purpose of the Study:
- To investigate changes in cellular water and macromolecular environments during cisplatin-induced apoptosis in acute myeloid leukemia (AML) cells using MT.
- To determine if MT parameters can serve as early biomarkers for apoptosis in AML.
Main Methods:
- Magnetization transfer (MT) measurements were conducted on AML cells at early (36h) and late (48h) post-cisplatin treatment.
- A two-pool model was fitted to MT data acquired at varying saturation powers and offset frequencies.
- Key parameters analyzed included magnetization transfer ratio (MTR), macromolecular proton fraction (M(0B)), and relaxation times (T1, T2).
Main Results:
- No significant changes in MT parameters were observed at early stages of apoptosis.
- At late stages, while MTR remained unchanged, quantitative analysis revealed a decreased macromolecular proton fraction (M(0B)) and increased free water T2 relaxation time.
- An increased ratio of exchange rate to free water T1 relaxation rate (R × M(0B)/R(1A)) was noted, primarily driven by changes in the free water pool.
Conclusions:
- Magnetization transfer parameters, particularly quantitative ones, can detect late-stage alterations in cellular composition during AML apoptosis.
- Changes in the MT spectrum during late apoptosis are mainly influenced by the free water pool, not early molecular changes.
- MT-derived parameters may offer insights into cellular dynamics but do not appear to be sensitive early biomarkers for cisplatin-induced apoptosis in AML.
