dextran

• Dextran


  A complex, branched glucan (polysaccharide made of many glucose molecules) composed of chains of varying lengths (from 10 to 150kilodaltons)
• Dextran


  • Used medicinally as an antithrombotic (anti-platelet), to reduce blood viscosity, and as a volume expander in anemia
  • Straight chain consists of α-1,6 glycosidic linkages between glucose molecules, while branches begin from α-1,4 linkages (and in some cases, α-1,2 and α-1,3 linkages as well)
  • Synthesized from sucrose by certain lactic-acid bacteria, the best-known being Leuconostoc mesenteroides and Streptococcus mutans
  • Dental plaque is rich in dextrans
  • Also formed by the lactic acid bacterium Lactobacillus brevis to create the crystals of tibicos, or water kefir fermented beverage which supposedly has some health benefits
• Microsurgery uses of dextran

  • Used commonly by microsurgeons to decrease vascular thrombosis
  • Antithrombotic effect is mediated through its binding of erythrocytes, platelets, and vascular endothelium, increasing their electro negativity and thus reducing erythrocyte aggregation and platelet adhesiveness
  • Reduces factor VIII-Ag Von Wille brand factor, thereby decreasing platelet function
  • Clots formed after administration of dextrans are more easily lysed due to an altered thrombus structure (more evenly distributed platelets with coarser fibrin)
  • Inhibits α-2 antiplasmin, serving as a plasminogen activator and therefore possessing thrombolytic features
• Other medical uses of dextran


  • Used in some eye drops as a lubricant
  • Used in certain intravenous fluids to solubilise other factors, e.g. iron (=iron dextran)
  • Provides an osmotically neutral fluid that once in the body is digested by cells into glucose and free water
  • Occasionally used to replace lost blood in emergency situations, when replacement blood is not available, but must be used with caution as it does not provide necessary electrolytes and can cause hyponatremia or other electrolyte disturbances
  • Increases blood sugar levels
• Laboratory uses of dextran


  • Used in the osmotic stress technique for applying osmotic pressure to biological molecules
  • Used in some size-exclusion chromatography matrices; an example is Sephadex
  • Used in bead form to aid in bioreactor applications
  • Used in immobilization in biosensors
  • Preferentially binds to early endosomes; fluorescently-labelled dextran can be used to visualize these endosomes under a fluorescent microscope
  • Can be used as a stabilising coating to protect metal nanoparticles from oxidation and improve biocompatibility
  • Dextran coupled with a fluorescent molecule(such as FITC) can be used to create concentration gradients of diffusible molecules for imaging and allow subsequent characterization of gradient slope
  • Used to make microcarriers for industrial cell culture
• Side effects of dextran

  • Relatively few side-effects but can be very serious, including anaphylaxis, volume overload, pulmonary edema, cerebral edema, or platelet dysfunction
  • An uncommon but significant complication is acute renal failure, with the pathogenesis being a subject of debate (direct toxic effect on tubules and glomerulus versus intraluminal hyperviscosity)
  • Patients with history of diabetes mellitus, renal insufficiency, or vascular disorders are most at risk
  • Avoidance of dextran therapy is recommended in patients with chronic renal insufficiency and CrCl<40 cc per minute