the present invention relates to the fields of medicine , cell biology , molecular biology and genetics . in particular , the present invention provides methods to isolate and purify microvesicles from cell culture supernatants and biological fluids . the present invention also provides pharmaceutical compositions of microvesicles to promote or enhance wound healing , stimulate tissue regeneration , remodel scarred tissue , modulate immune reactions , alter neoplastic cell growth and / or mobility , or alter normal cell growth and / or mobility . the present invention also provides compositions of microvesicles to be used as diagnostic reagents , and methods to prepare the compositions of microvesicles .