Purpose: Mitochondrial dysfunction has been attributed a critical role in the etiology and pathogenesis of numerous diseases, and is manifested by alterations of the organelle's membrane potential (Δψm). This suggests that Δψm measurement can be highly useful for diagnostic purposes. In the current study, we characterized the capability of the novel PET agent 18F-fluorobenzyl triphenylphosphonium ( 18F-FBnTP) to assess Δψm, compared with the well-established voltage sensor 3H-tetraphenylphosphonium ( 3H-TPP). Methods: 18F-FBnTP and 3H-TPP uptake under conditions known to alter Δψm and plasma membrane potential (Δψp) was assayed in the H345 lung carcinoma cell line. 18F-FBnTP biodistribution was assessed in CD1 mice using dynamic PET and ex vivo gamma well counting. Results: 18F-FBnTP and 3H-TPP demonstrated similar uptake kinetics and plateau concentrations in H345 cells. Stepwise membrane depolarization resulted in a linear decrease in 18F-FBnTP cellular uptake, with a slope (-0.58±0.06) and correlation coefficient (0.94±0.07) similar (p>0.17) to those measured for 3H-TPP (-0.63±0.06 and 0.96±0.05, respectively). Selective collapse of Δψm caused a substantial decrease in cellular uptake for 18F-FBnTP (81.6±8.1%) and 3H-TPP (85.4±6.7%), compared with control. Exposure to the proapoptotic staurosporine, known to collapse Δψm, resulted in a decrease of 68.7±10.1% and 71.5±8.4% in 18F-FBnTP and 3H-TPP cellular uptake, respectively. 18F-FBnTP accumulated mainly in kidney, heart and liver. Conclusion: 18F-FBnTP is a mitochondria-targeting PET radiopharmaceutical responsive to alterations in membrane potential with voltage-dependent performance similar to that of 3H-TPP. 18F-FBnTP is a promising new voltage sensor for detection of physiological and pathological processes associated with mitochondrial dysfunction, such as apoptosis, using PET.
|Original language||English (US)|
|Number of pages||9|
|Journal||European Journal of Nuclear Medicine and Molecular Imaging|
|State||Published - Dec 2007|
- Membrane potential
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging