Abstract: Platelets are induced to proliferate, form extensions and produce daughter cells by various methods, including culturing platelets under thrombocytopenic conditions. Expansion of platelet cell numbers increases the storage life of platelets. Modulation of RT activity can be used to produce new daughter platelets. Therefore, the invention provides a new therapeutic use for RT inhibitors that can now be used for treatment of thrombocytopenia and related disorders. Likewise, application of soluble protein factor that may be secreted and/or released by platelets cultured under thrombocytopenic conditions may also be used as a therapeutic agent to increase platelet numbers.