There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Abstract
Significance: Optical imaging using the endogenous fluorescence of metabolic cofactors
has enabled nondestructive examination of dynamic changes in cell and tissue function
both in vitro and in vivo . Quantifying NAD(P)H and FAD fluorescence through an
optical redox ratio and fluorescence lifetime imaging (FLIM) provides sensitivity
to the relative balance between oxidative phosphorylation and glucose catabolism.
Since its introduction decades ago, the use of NAD(P)H imaging has expanded to include
applications involving almost every major tissue type and a variety of pathologies.
Recent Advances: This review focuses on the use of two-photon excited fluorescence
and NAD(P)H fluorescence lifetime techniques in cancer, neuroscience, tissue engineering,
and other biomedical applications over the last 5 years. In a variety of cancer models,
NAD(P)H fluorescence intensity and lifetime measurements demonstrate a sensitivity
to the Warburg effect, suggesting potential for early detection or high-throughput
drug screening. The sensitivity to the biosynthetic demands of stem cell differentiation
and tissue repair processes indicates the range of applications for this imaging technology
may be broad. Critical Issues: As the number of applications for these fluorescence
imaging techniques expand, identifying and characterizing additional intrinsic fluorophores
and chromophores present in vivo will be vital to accurately measure and interpret
metabolic outcomes. Understanding the full capabilities and limitations of FLIM will
also be key to future advances. Future Directions: Future work is needed to evaluate
whether a combination of different biochemical and structural outcomes using these
imaging techniques can provide complementary information regarding the utilization
of specific metabolic pathways.