1. Radiat Res. 2009 Aug;172(2):220-5.

A New EPR oximetry protocol to estimate the tissue oxygen consumption in vivo.

Diepart C, Jordan BF, Gallez B.

Laboratory of Biomedical Magnetic Resonance, Université catholique de Louvain,
B-1200 Brussels, Belgium.

Abstract The oxygen consumption rate in tumors affects tumor oxygenation and
response to therapies. A new EPR method was developed to measure tissue oxygen
consumption non-invasively. The protocol was based on the measurement of pO(2)
during a carbogen challenge. The following sequence was used: (1) basal value
during air breathing; (2) saturation of tissue with oxygen by carbogen breathing;
(3) switch back to air breathing. The assumption was that the kinetics of the
return to the basal value after oxygen saturation would be governed mainly by
tissue oxygen consumption. This challenge was applied in hyperthyroid mice
(generated by chronic treatment with l-thyroxine) and control mice because
hyperthyroidism is known to dramatically affect the oxygen consumption rate of
tumor and muscle cells. Muscle and tumor cells from the hyperthyroid mice
consumed oxygen faster than muscle and tumor cells from the control mice, which
is consistent with the results of in vitro studies. Tumor perfusion was not
affected by the treatment with l-thyroxine. This method gives an index that may
reasonably be ascribed to the local oxygen consumption and has the unique
advantage of being adaptable to in vivo studies.

PMID: 19630526 [PubMed - indexed for MEDLINE]