Effect of temperature on permeation of low-density lipoprotein particles through human carotid artery tissues

Quantification of the diffusion of small molecules and large lipid transporting lipoproteins across arterial tissues could be useful in elucidating the mechanism(s) of athero-sclerosis. Optical coherence tomography (OCT) was used to determine the effect of temperature on the rate of diffusion of glucose and low-density lipoproteins (LDL) in human carotid endarterectomy tissue in vitro. The permeability rate for glucose was calculated to be (3.51 ± 0.27) ×10^-5cm/s (n = 13) at 20 ° C, and (3.70 ± 0.44)×10^-5 cm/s (n = 5) at 37 °C; for LDL the rate was (2.42 ± 0.33)×10^-5cm/s (n = 5) at 20 ° C and (4.77 ± 0.48)×10^-5cm/s (n = 7) at 37 ° C, where n is the number of samples. These results demonstrate that tem-perature does not significantly influence the permeation of small molecules (e.g. glucose), however, raising the temperature does significantly increase the permeation of LDL. These results provide new information about the capacity of an atherogenic lipoprotein to traverse the intimal layer of the artery. These results also demonstrate the potential of OCT for elucidating the dynamics of lipoprotein perfusion across the arterial wall.