The blood is rich in different types of mesoderm derived stem and progenitor cells

Abstract

The blood and bone marrow have been thoroughly investiagated for more than a century, but we are still gaining surprising new information's. Blood transports different mature cells such as erythrocytes, platelets and granulocytes, but curiously, the blood is also transporting a number of non-differentiated cells of various mesodermal lineages: hematopoietic and mesenchymal stem and progenitor cells, endothelial progenitor cells and very small embryonal like cells are some of the most impressive examples. In adults the bone marrow is the source of practiclly all cells that could be found in the blood. Stem and progenitor cells egress from the bone marrow and home to the bone marrow or various tissues in a highly regulated manner. The fact that the hematopoetic stem and progenitor cells traffic through the blood and repopulate the bone marrow niche is largely explored in stem cell therapy in human medicine. In this review we will briefly describe the main characteristics of stem and progenitor cells, the mechanisms of their mobilization from the bone marrow and homing to target tissues. Also, the history and importance of the fact that different stem, progenitor and precursor cells could be isolated from the blood circulation will be discussed in the light of informations concerning their use in human and veterinary medicine.

Ispitivanja krvi i koštane srži se sistematski sprovode duže od sto godina, ali su ova tkiva i dalje izvor novih podataka od značaja za humanu i veterinarsku medicinu. Krvlju cirkulišu različite zrele ćelije kao što su eritrociti, trombociti i granulociti, ali i mali broj nediferenciranih ćelija mezodermalnog porekla: hematopoteske i mezenhimske matične ćelije i ćelije progenitori, progenitori endotelnih ćelija i jako male ćelije nalik embrionalnim. Kod odraslih organizama, koštana srž je izvor praktično svih ćelija koje se mogu naći u krvi. Mobilizacija matičnih ćelija i ćelija progenitora iz koštane srži u krv, i njihov povratak u koštanu srž ili odlazak u druga tkiva je regulisan kompleksnim procesima. Upotreba matičnih ćelija hematopoeze i ćelija progenitora u humanoj medicini, zasniva se na činjenici da mogu da se mobilišu u krv i da repopulišu koštanu srž proizvodeći zrele ćelije krvi. U ovom preglednom članku će biti opisane osnovne karakteristike matičnih ćelija i ćelija progenitora, mehanizmi mobilizacije i prelaska u tkiva. Takođe, značaj činjenice da se u krvi mogu naći različite matične ćelije i progenitorske i prekursorske ćelije je stavljena u kontekst njihove primene u humanoj i veterinarskoj medicini.