Inflammation 

Inflammation is the first line of immune defense when the body encounters an attack such as a viral or bacterial infection, an injury or an allergy. It involves immune cells, better known as white blood cells. The resulting physiological reaction (normal reaction of the body) appears as redness, swelling, heat, pain, or even an alteration of the proper functioning of the affected organ.

In the case of atherosclerosis, the entry of LDL cholesterol particles into the artery walls of the heart acts as an aggressor and causes a physical inflammatory reaction (see figure). The white blood cells then pass through the arterial wall to absorb the LDL cholesterol particles in order to clean it. Once loaded with cholesterol, the white blood cells accumulate and form plaque. They then release pro-inflammatory substances that increase the permeability of the arterial wall, allowing the entry of new LDL cholesterol particles and white blood cells. A vicious circle thus begins, which promotes the thickening of the plaque. The greater the aggression of LDL, the greater the plaque and the more damage it can cause.

Inflammation is also a well-known feature of type 2 diabetes. Certain inflammatory substances (cytokines) increase in patients with diabetes. Various cell types can produce these inflammatory cytokines and then release them into the bloodstream, where their interactions with tissues trigger an immune response. In the context of type 2 diabetes, the expanding adipose tissue (body fat) appears to be a major site of production of these inflammatory cytokines.