Scheme of lipid circulation in the human body. Hepatocyte (1) synthesizes VLDL (2), which moves into the blood through pore in endothelial cells of liver sinusoid (red arrows). Next, VLDL arrives to the blood capillary (Capillary) with continuous endothelium and gives cholesterol to the APM of ECs. Unfolded ApoA1 is synthesized by hepatocytes and also arrived to this capillary (yellow arrows). It passes endothelium through intercellular contacts and appears in interstitium. There, it contacts with the BLPM of ECs and takes cholesterol there forming HDL. ChM (3) is formed by enterocyte (4). It is transported to interstitium and then to the lumen of lymph capillary and delivered to the blood capillary lined with the continuous endothelium dark green arrows). In the capillary, VLDL and ChM contact with the APM (black double-sided arrows) and insert cholesterol and fatty acids into it. After this, ChM and VLDL are transformed into LDL (5), which are delivered to hepatocytes passing through pores in sinusoidal endothelium (blue arrow). Finally, LDLs are taken by LDL receptors on the PM of hepatocytes. Part of LDL (6) contacts with ECs, lining aorta in the areas of altered flow pattern and can pass into intima there through leaky contacts. Apo1 passes endothelium through intercellular contacts or using transcytosis and appeared inside interstitium (7). It contacts with the baso-lateral PM of ECs and takes cholesterol and fatty acids from it. Next, HDL interacts with the PM of tissue cell and takes cholesterol when it is necessary. Then, ApoA1 is transformed into HDL of two types (8, 9). After this, HDLs are absorbed by lymph capillaries and delivered to the blood (yellow arrows). Finally, HDLs pass through pores (yellow arrow near 1) of sinusoidal endothelium and reach scavenger receptors of the PM of hepatocytes (1). Abbreviations: APM, apical PM; ChM, chylomicron; HDL, high-density lipoprotein; LDL, low-density lipoproteins; PM, plasma membrane; VLDL, very LDL.