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Staranje je zapleten, več faktorski proces, ki prizadane celice, tkiva in organe. S staranjem organizma se stara tudi imunski sistem, ki je sicer ključen za obrambo organizma pred škodljivim okoljem. S starostjo povezane okvare imunskega sistema vodijo v nastanek večine s starostjo povezanih bolezni kot so rak, avtoimunske bolezni in srčno-žilne bolezni ter povročijo povečano dovzetnost posameznika za okužbe. Ena izmed možnih terapij, ki bi lahko izboljšala delovanje imunskega sistema v starosti, je presaditev mladih krvotvornih matičnih in progenitorskih celic (KMPC), ki bi jih posamezniku odvzeli in shranili v njegovi mladosti ter ponovno presadili v njegovi starosti. Sklepamo, da bi na ta način mlade in zdrave KMPC po presaditvi »pomladile« stari imunski sistem ter izboljšale njegovo delovanje, ob enem pa bi posamezniku podaljšali njegovo življensko dobo. Omenjeni princip se imunuje heterohrona avtologna presaditev mladih krvotvornih matičnih celic. V raziskavi smo v mišjem modelu uporabili nov način presaditve KMPC s predhodno mobilizacijo endogenih KMC v periferno kri. V ta namen smo uporabili molekulo CASIN, ki začasno izprazni nišo kostnega mozga prejemnika, na ta način pa omogoči večjemu številu presajenih celic pritrjanje vanjo. Z uporabo molekule CASIN smo po presaditvi mladih KMPC starim prejemnicam dosegli visok odstotek donorskega himerizma, dokazali nekatere izboljšave v imunskem sistemu in rahlo povišali mediano preživetja. Kljub temu pa bi bilo za prenos v humano medicino potrebno izvesti dodatne raziskave, ki bi potrdili ugodne učinke tovrstne terapije. Aging is a complex multi-factorial process that affects cells, tissues and organs. It also affects the immune system, which is crucial for the body's defense against the harmful environment. Age-related defects of the immune system lead to the development of most age-related diseases, such as cancer, autoimmune and cardiovascular diseases and cause an increased susceptibility to infections. One of the strategies that could improve the function of the immune system of an old individual is the transplantation of young hematopoietic stem and progenitor cells (HSCs) which would be collected from an individual in his/her youth and cryopreserved for a long time. After re-infusion later in life of the same individual, young and healthy HSPCs could »rejuvenate« the old immune system and improve its functioning. Furthermore, individuals lifespan could be prolonged. The process is called heterochronous autologous hematopoietic stem cell transplantation. In this study we used a new method of HSC transplantation with prior mobilization of endogenous HSCs into peripheral blood. For this purpose, we used the molecule CASIN, which temporarily empties the recipient's niche, thus allowing engraftment of a larger number of transplanted cells. With the use of the CASIN molecule, we achieved a high percentage of donor chimerism after transplantation of young HSPCs into old recipients. In the recipients of young HSPCs, we detected some improvements in the function of the immune system and a slighty higher median lifespan. Nevertheless, for translation into human medicine, additional research would be needed to confirm the beneficial effects of this type of therapy.

Mezenhimske stromalne celice (MSC) so eden glavnih virov za celične terapije in tkivno inženirstvo. Sposobne so samoobnavljanja in diferenciacije, lahko uravnavajo imunski odziv in sodelujejo pri celjenju poškodb. S staranjem se njihove regenerativne sposobnosti zmanjšajo. Pri terapijah z MSC se zato poraja vprašanje, kako starost darovalca in celic vpliva na izid zdravljenja. V magistrskem delu smo skušali ugotoviti, kako starost miši BALB/c vpliva na lastnosti njihovih MSC. S pretočno citometrijo smo spremljali izražanje celičnih označevalcev med gojenjem mladih in starih celic, spremljali smo proliferacijo celic s testom MTT, določali smo sposobnost migracije celic s testom celjenja ran in prisotnost senescentnih celic v kulturi. Ugotovili smo, da se mlade celice hitreje delijo, imajo nižji delež senescentnih celic v kulturi in slabše migracijske sposobnosti v primerjavi s starimi celicami. Med izražanjem celičnih označevalcev med skupinama nismo opazili razlik. Mesenchymal stromal cells are one of the main sources for cell therapy and tissue engineering. They are capable of self-renewal and differentiation. They can regulate a body's immune response and participate in its wound-healing process. Their regenerative abilities reduce as they age. MSC therapies therefore raise a question of how the age of the donor affects the outcome of the treatment. In this master's thesis, we tried to determine how the age of BALB/c mice affects the properties of their MSC. We monitored the expression of cell markers during cell culture with flow cytometry. We monitored cell proliferation rate with the MTT assay and analyzed mouse MSC's migration capacities with wound-healing assay. By measuring the β-galactosidase activity we determined the presence of senescent cells in culture. We discovered that young cells divide more rapidly, have a lower proportion of senescent cells in culture and have lower migration capacity when compared to older cells. The expression of cell markers is the same for both cell groups.