Heparin (from Ancient Greek ηπαρ (hepar), liver), also known as unfractionated heparin, a highly sulfated glycosaminoglycan, is widely used as an injectable anticoagulant, and has the highest negative charge density of any known biological molecule.

It can also be used to form an inner anticoagulant surface on various experimental and medical devices such as test tubes and renal dialysis machines.

Although it is used principally in medicine for anticoagulation, its true physiological role in the body remains unclear, because blood anticoagulation is achieved mostly by heparan sulfate proteoglycans derived from endothelial cells

Heparin is usually stored within the secretory granules of mast cells and released only into the vasculature at sites of tissue injury. It has been proposed that, rather than anticoagulation, the main purpose of heparin is defense at such sites against invading bacteria and other foreign materials.

In addition, it is observed across a number of widely different species, including some invertebrates that do not have a similar blood coagulation system.

It is on the World Health Organization's List of Essential Medicines, a list of the most important medication needed in a basic health system.

Two types of heparins are commonly used as anticoagulants – unfractionated heparin (UFH) and low-molecular-weight heparins (LMWHs). UFH has been used for the prevention and treatment of thrombosis for several decades. UFH has variable anticoagulant effects and pharmacological properties and also has limited bioavailability and highly variable anticoagulant response. LMWHs are derived from UFH by depolymerization. Each LMWH product has a specific molecular weight distribution that determines its anticoagulant activity and duration of action. LMWHs are associated with a predictable dose–response and have fewer non-haemorrhagic side-effects. Because of these clinical advantages, LMWHs have gradually replaced UFH for most indications.

  • heparin.txt
  • Last modified: 2023/03/31 11:01
  • by administrador