Heparin - Other Uses/information

Other Uses/information

• Heparin gel (topical) may sometimes be used to treat sports injuries. It is known that the diprotonated form of histamine binds site specifically to heparin. The release of histamine from mast cells at a site of tissue injury contributes to an inflammatory response. The rationale behind the use of such topical gels may be to block the activity of released histamine, and so help to reduce inflammation.
• Heparin gains the capacity to initiate angiogenesis when its copper salt is formed. Copper-free molecules are non-angiogenic. In contrast heparin may inhibit angiogenesis when it is administered in the presence of corticosteroids. This anti-angiogenic effect is independent of heparins anticoagulant activity.

• Test tubes, Vacutainers, and capillary tubes that use the lithium salt of heparin (lithium heparin) as an anticoagulant are usually marked with green stickers and green tops. Heparin has the advantage over EDTA of not affecting levels of most ions. However, it has been shown that the levels of ionized calcium may be decreased if the concentration of heparin in the blood specimen is too high. Heparin can interfere with some immunoassays, however. As lithium heparin is usually used, a person's lithium levels cannot be obtained from these tubes; for this purpose, royal-blue-topped Vacutainers containing sodium heparin are used.

• Heparin-coated blood oxygenators are available for use in heart-lung machines. Among other things, these specialized oxygenators are thought to improve overall biocompatibility and host homeostasis by providing characteristics similar to native endothelium.

• The DNA binding sites on RNA polymerase can be occupied by heparin, preventing the polymerase binding to promoter DNA. This property is exploited in a range of molecular biological assays.

• Common diagnostic procedures require PCR amplification of a patient's DNA, which is easily extracted from white blood cells treated with heparin. This poses a potential problem, since heparin may be extracted along with the DNA, and it has been found to interfere with the PCR reaction at levels as low as 0.002 U in a 50 μL reaction mixture.

• Immobilized heparin can be used as an affinity ligand in protein purification. The format of immobilized heparin can vary widely from coated plastic surfaces for diagnostic purposes to chromatography resin. Most types of immobilized heparin can be used in three ways. The first is to use heparin to select out specific coagulation factors or other types of heparin-binding proteins from a complex mixture of non-heparin-binding proteins. Specific proteins can then be selectively dissociated from heparin with the use of differing salt concentrations or by use of a salt gradient. The second use is to use heparin as a high-capacity cation exchanger. This use takes advantage of heparin's high number of anionic sulfate groups. These groups will capture molecules or proteins with an overall positive charge, i.e., play no role in coagulation and do not bind nucleotides. The third use for immobilized heparin is group-specific purification of RNA and DNA-binding proteins such as transcription factors and/or virus-coat proteins. This methodology takes advantage of heparin's structural similarity to RNA and DNA, being a negatively charged sugar-containing macromolecule.

• Heparin does not break up fibrin, it only prevents conversion of fibrinogen to fibrin. Only thrombolytics can break up a clot.