Chylinki

Chylinki, also known as lymph chylomicrons, are lipoproteins formed in the enterocytes (absorptive cells) of the small intestine. They are a type of emulsion, consisting primarily of triglycerides (fats), cholesterol, phospholipids, and apolipoproteins.

Chylinki are produced in response to dietary fat absorption. During digestion, fats are broken down into smaller components like fatty acids and monoglycerides. These are then absorbed into the enterocytes, where they are re-esterified into triglycerides. These triglycerides, along with cholesterol, phospholipids, and apolipoproteins (notably apolipoprotein B-48), are packaged into chylomicrons.

Once assembled, chylomicrons are too large to enter directly into blood capillaries. Instead, they are secreted from the enterocytes into the lymphatic vessels (lacteals) located in the villi of the small intestine. From the lacteals, they enter larger lymphatic vessels and eventually drain into the bloodstream via the thoracic duct, which empties into the left subclavian vein.

In the bloodstream, chylomicrons deliver dietary triglycerides to various tissues, primarily muscle and adipose tissue, where the triglycerides are hydrolyzed by the enzyme lipoprotein lipase (LPL), releasing fatty acids for energy or storage.

As triglycerides are removed, the chylomicron becomes smaller, and its composition changes. These smaller particles are called chylomicron remnants. Chylomicron remnants are taken up by the liver via receptor-mediated endocytosis, where they are further processed.

Disorders in chylomicron metabolism, such as familial chylomicronemia syndrome (also known as lipoprotein lipase deficiency or Type I hyperlipoproteinemia), can lead to an accumulation of chylomicrons in the blood, resulting in hypertriglyceridemia, eruptive xanthomas, lipemia retinalis, and pancreatitis.