"...atherosclerosis – the accumulation of sterols and inflammatory cells within an artery wall which may (or may not) narrow the lumen of the artery."
"To be clear, statistically speaking, this condition (atherosclerotic induced ischemia or infarction) is the most common one that will result in the loss of your life. For most of us, atherosclerosis (most commonly within coronary arteries, but also carotid or cerebral arteries) is the leading cause of death, even ahead of all forms of cancer combined. Hence, it's worth really understanding this problem."
"Cholesterol and triglycerides are not soluble in plasma (i.e., they can't dissolve in water) and are therefore said to be hydrophobic."
"To be carried anywhere in our body, say from your liver to your coronary artery, they need to be carried by a special protein-wrapped transport vessel called a lipoprotein."
"As these 'ships' called lipoproteins leave the liver they undergo a process of maturation where they shed much of their triglyceride "cargo" in the form of free fatty acid, and doing so makes them smaller and richer in cholesterol."
"Special proteins, apoproteins, play an important role in moving lipoproteins around the body and facilitating their interactions with other cells. The most important of these are the apoB class, residing on VLDL, IDL, and LDL particles, and the apoA-I class, residing for the most part on the HDL particles."
"Cholesterol transport in plasma occurs in both directions, from the liver and small intestine towards the periphery and back to the liver and small intestine (the 'gut')."
"The major function of the apoB-containing particles is to traffic energy (triglycerides) to muscles and phospholipids to all cells. Their cholesterol is trafficked back to the liver. The apoA-I containing particles traffic cholesterol to steroidogenic tissues, adipocytes (a storage organ for cholesterol ester) and ultimately back to the liver, gut, or steroidogenic tissue."
"All lipoproteins are part of the human lipid transportation system and work harmoniously together to efficiently traffic lipids. As you are probably starting to appreciate, the trafficking pattern is highly complex and the lipoproteins constantly exchange their core and surface lipids."
"The sine qua non of atherosclerosis is the presence of sterols in arterial wall macrophages. Sterols are delivered to the arterial wall by the penetration of the endothelium by an apoB-containing lipoprotein, which transport the sterols. In other words, unless an apoB-containing lipoprotein particle violates the border created by an endothelium cell and the layer it protects, the media layer, there is no way atherogenesis occurs.
"The progression from a completely normal artery to an atherosclerotic one which may or may not be "clogged" follows a very clear path: an apoB containing particle gets past the endothelial layer into the sub-endothelial space, the particle and its cholesterol content is retained and oxidized, immune cells arrive, an initially-beneficial inflammatory response occurs that ultimately becomes maladaptive leading to complex plaque."
"While inflammation plays a key role in this process, it's the penetration of the apoB particle, with its sterol passengers, of the endothelium and retention within the sub-endothelial space that drive the process."
"The most numerous apoB containing lipoprotein in this process is certainly the LDL particle, however Lp(a) (if present) and other apoB containing lipoproteins may play a role."