OCT for monitoring the respiratory epithelium: OCT for monitoring the respiratory epithelium: Muco-ciliary clearance (MCC) is the self-clearing mechanism of the respiratory tract essential for the prevention of lung infections. When the MCC mechanism is defective, which can be associated with pulmonary diseases Cystic Fibrosis (CF) and Chronic Obstructive Pulmonary Disease (COPD), there are severe and devastating consequences for lung function. Mucus proteins create a matrix-like porous mesh that traps dangerous pathogens to protect the airways. When mucus becomes dehydrated due to disease, it collapses the MCC's cilia lining and pathogens are not cleared from the lungs. In order to monitor disease and determine treatment options, we must know more about the MCC system and the nanostructure of mucus in this dehydrated state.
Using our PS-OCT system, we have demonstrated relative quantification of cilia beat frequencies (Oldenburg et al, 2012) at a single location on an HBEC. Our laboratory has recently constructed a parallel OCT system capable of capturing a B-mode image in a single snapshot. With this system, we have quantified cilia beat frequency over an entire cross-section of an HBEC (Barrick et al, 2016), as shown in Figure 1.
Most recently, our laboratory has employed DS-OCT to monitor clinically used mucus thinning treatments. DS-OCT captures the diffusion rate of gold nanorods (GNRs) as they move throughout mucus. DS-OCT is uniquely capable of resolving the diffusion rate of GNRs in space on short timescales. This capability allows us to monitor the changes in mucus during treatment therapies, as demonstrated in Figure 2 with isotonic and hypertonic saline (IS and HS) treatments. (Blackmon et al, 2017). We expect this novel technique of monitoring mucus weight percent in real-time will lead to better understanding of mucus thinning treatments, and eventually to an in vivo measure of treatment effectiveness for patients with respiratory disease.