Rapid recovery of platelet count following administration of liposome-encapsulated clodronate in a mouse model of immune thrombocytopenia

Br J Haematol. 2002 Feb;116(2):357-66.

Abstract

Immune thrombocytopenic purpura (ITP) is a haematological disorder characterized by increased platelet consumption. The destruction of platelets is mediated by the reticulo-endothelial system (RES), particularly by splenic and hepatic macrophages. Previously, we demonstrated in a mouse model of thrombocytopenia that the depletion of these cells by liposome-encapsulated clodronate (LIP-CLOD) induces the recovery of the platelet count. We now report that LIP-CLOD is capable of reversing the thrombocytopenia with minimal effects on both, functional RES integrity and platelet functionality. Our data indicate that thrombocytopenic mice treated with low doses of LIP-CLOD/body weight increase the platelet count to haemostatically safe values within 18 h of treatment. The predictable bleeding time was significantly decreased in these mice, suggesting that the circulating platelets have enhanced haemostatic capacity. Platelet functionality measured through the ADP-induced fibrinogen-binding assay showed normal platelet activation after treatment. Regarding immunological competence, mice treated with LIP-CLOD showed similar antibody titres against sheep red blood cells. However, antibody-dependent cell-mediated cytotoxicity carried out by splenocytes was reduced. All these data demonstrate that LIP-CLOD deserves consideration as a potential therapeutic approach in thrombocytopenic states in which the rapid increase of platelet count is the primary goal.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antimetabolites / therapeutic use*
  • Clodronic Acid / therapeutic use*
  • Dose-Response Relationship, Drug
  • Female
  • Liposomes
  • Male
  • Mice
  • Models, Animal
  • Phagocytosis / drug effects
  • Platelet Activation
  • Platelet Count
  • Thrombocytopenia / blood
  • Thrombocytopenia / drug therapy*

Substances

  • Antimetabolites
  • Liposomes
  • Clodronic Acid