Functional fibered confocal microscopy: a promising tool for assessing tendon regeneration.

This work advances fibered confocal microscopy (FCM) as a functional imaging platform for in vivo assessment of tissue mechanics. Building on our earlier studies demonstrating proof of principle and introducing an analytical framework for FCM image processing, here we present data that improve and validate several critical aspects of FCM. Specifically, we have considerably reduced the invasiveness of the imaging procedure, and verified that endoscopic imaging through a transcutaneous access point does not induce functional changes in passive ankle joint biomechanics. We have also verified that periodic (weekly) measurements on uninjured tendons are reproducible. Importantly, we have further proven that the method can sensitively detect and quantify compromised tendon mechanics in injured tendons. These incremental but essential developments further push FCM measurement of tissue mechanics from a novel concept to a usable tool that fills an important niche by functionally imaging living tissue at the highest available spatial resolution of any currently available in vivo imaging method. It is expected that functional FCM imaging will eventually enable accelerated screening of preclinical therapies, and allow researchers to quantifiably relate implanted cell behavior with resulting changes in tissue structure and function.