Optical coherence tomography in quantifying the permeation of human plasma lipoproteins in vascular tissues

Atherosclerosis is the most common underlying cause of vascular disease, occurring in multiple arterial beds including the carotid, coronary, and femoral arteries. Atherosclerosis is an inflammatory process occurring in arterial tissue, involving the subintimal accumulation of low-density lipoproteins (LDL). Little is known about the rates at which these accumulations occur. Measurements of the permeability rate of LDL, and other lipoproteins such as high-density lipoprotein (HDL) and very low-density lipoprotein (VLDL), could help gain a better understanding of the mechanisms involved in the development of atherosclerotic lesions. The permeation of VLDL, LDL, HDL, and glucose was monitored and quantified in normal and diseased human carotid endarterectomy tissues at 20°C and 37°C using optical coherence tomography (OCT). The rates for LDL permeation through normal tissue at 20°C was (3.16 ± 0.37) × 10-5 cm/sec and at 37°C was (4.77 ± 0.48) × 10-5 cm/sec, significantly greater (p<0.05) than the rates for diseased tissue at these temperatures ((1.97 ± 0.34) × 10-5 cm/sec and (2.01 ± 0.23) × 10-5 cm/sec, respectively). The observed results support previous suggestions of an enhanced transport mechanism specific to LDL. This study effectively uses optical coherence tomography to measure the rates of permeation of vascular tissue by the range of naturally occurring lipoproteins.