Literatura académica sobre el tema "Cellule staminali, rene, gravidanza"

The aim of this study was to better define, by immunohistochemistry, the molecular markers of renal stem/progenitor cells localized in the different niches of ten human preterm kidneys with gestational age ranging from 11 up to 25 weeks. Our data evidence the existence of multiple stem/progenitor pools in different zones of the human developing kidney that are characterized by different phenotypes: capsular stem cells were EMA (MUC1)+, MDM2+, Vimentin+ and Wnt1+; progenitors of the sub-capsular nephrogenic zone were MDM2+ and Wnt1+; cap mesenchymal cells were EMA (MUC1)+, CD15+, vimentin+, Wt1+, CD10+, Bcl2+, Wnt1+ and PAX2+; interstitial progenitor cells were Vimentin+, Wt1+ and α1Anti-tripsin +. Our data evidence the existence of multiple stem/progenitor cell pools in the fetal and neonatal human kidney. Progenitors of these different pools are characterized by a peculiar phenotype, indicating a different differentiation stage of these renal progenitors. A better knowledge of the molecular markers expressed by renal stem/progenitors might represent a relevant datum for researchers involved in renal regenerative medicine.

In recent years, numerous cancers have been described as having a "cancer stem cell" (CSC) population also known as "cancer initiating cells". CSCs refer to a subset of tumour cells that has the ability to self-renew and generate the diverse cells that comprise the tumor. Their name derives from their "stem-like" properties and ability to continually sustain tumorigenesis. CSCs have the same properties that define a normal tissue adult stem cell, even if they are aberrant: self-renewal and differentiation. Renal cell carcinoma (RCC) accounts for about 3% of adult cancers and is among the 10 most common malignancies in Europe. RCC has several morphological subtypes and clear cell RCC accounts for ~80% of cases. RCC has a late diagnosis and is therapy resistant. In renal pathologies there are situation in which the presence and function of adult renal stem cells may have clinical relevance. In the last years the existence of different sources of renal stem cells has been proposed even if the phenotype of a resident stem cell of the kidney has not been exhaustively described. Even in RCC the definition of a kidney cancer stem cell may have a role for better understanding renal cell carcinoma biology. A number of approaches based on the exploitation of renal stem cell markers have allowed the prospective isolation of human renal stem cells, even if the relative promiscuity of these markers limits their usefulness when highly purified stem cells are needed. So we decided to use a functional approach for the isolation of normal and cancer stem cells of the kidney by culturing the cells in suspension, non-adherent conditions, at low density with specific growth factors. In these conditions only a little percentage of cells survives growing as spherical aggregates in suspension. We called them "nephrospheres". Using fluorescent lipophilic dyes PKH, we demonstrated the clonal origin of the spheres and the presence of a heterogeneous population inside the spheres. In fact the dye dilutes in active replicating cells while is retained in quiescent cells; we can observe in normal and cancer nephrospheres some most fluorescent cells, the quiescent stem cells, and some less fluorescent or not fluorescent cells, that are the active replicating progenitors. We performed a characterization of the nephrospheres by immunofluorescence after cytospin or FACS evaluating the expression of some epithelial and stem cell markers. By Real Time PCR we found that some genes related with stemness or involved in the maintenance of pluripotency are overexpressed in normal and cancer nephrospheres if compared with the corresponding differentiated primary cell cultures. We then evaluated the differentiative abilities of the cells derived from normal nephrospheres by culturing the cells in specific media and semisolid substrates; the cells are able to differentiate into epithelial and neuronal-like phenotype and to form tubular/glomerular-like tridimensional structures. We the isolated the stem cell population form normal nephrospheres on the basis of the PKH fluorescence. We identified 3 PKH populations: PKHhigh population, with a high level of fluorescence, PKHlow population, with a low level of fluorescence, and PKHneg population, negative for PKH. The populations were separated with cell sorting and cultivated to form spheres. Only PKHhigh cells were able to generate new spheres, demostrating that the PKHhigh cells represent the stem cell population inside the nephrospheres. Normal and cancer PKHhigh cells will be deeply characterized in the future.

I progenitori renali hanno un ruolo di primaria importanza nella capacità del rene di far fronte allo stress da filtrazione glomerulare e di ripristinare prontamente i podociti danneggiati durante la gravidanza. La stimolazione estrogenica guida tale adattamento e se carente può fare la differenza tra il successo della gravidanza e l’insorgenza di complicanze quali la preeclampsia. Questi risultati aggiungono un tassello in più verso l a comprensione dell’eziopatogenesi della preeclampsia, in quanto pongono il rene, in particolare la capacità dei progenitori renali di generare nuovi podociti, in risposta agli estrogeni, tra le cause che predispongono alla patologia. In vitro colture primarie di progenitori renali umani risultano essere sensibili alla stimolazione estrogenica che agisce attraverso il recettore ER α . Questo effetto trova riscontro negli esperimenti in vivo , attraverso cui è stato possibile dimostrare che la carenza del recettore α degli estrogeni sui progenitori renali ha effetti sulla loro capacità di differenziare in podociti. Il che predispone ad un maladattamento funzionale del rene alla gravidanza.

Mediante utilizzo di modelli murini transgenici, tecniche di imaging ad alta risoluzione ed analisi di Single-cell RNAseq, è sato possibile chiarire l’origine clonale delle lesioni crescentiche. Inoltre è stata identificata una molecola farmacologica in grado di garantire un miglior esito in seguito ad un evento di glomerulonefrite crescentica. Gli effetti benefici di questa molecola sono da ascrive ad una duplice azione: si verifica un blocco della proliferazione anormale dei progenitori renali e contemporaneamente si ha un aumento della rigenerazione renale.

Questo studio ha dimostrato che il carcinoma renale papillare (pRCC), uno dei 3 più frequenti tipi di RCC, origina dall’espansione clonale di una popolazione di cellule staminali residenti nel rene, i progenitori renali . In seguito ad un danno renale acuto , queste cellule sono in grado di rigenerare la porzione di tubulo renale danneggiata. Tuttavia, in seguito al danno si ha l’alterazione di alcune pathways che possono promuovere la loro trasformazione in cellula staminale tumorale (CSC, cancer stem cell). In particolare, abbiamo dimostrato con questo lavoro di tesi che l’overespressione della pathway di NOTCH1, è specifica per il pRCC di tipo 2 ed è associata ad una prognosi sfavorevole nell’uomo . Infine, abbiamo dimostrato che NOTCH1 promuove la trasformazione del progenitore renale, sia in vivo che in vitro promuovendone la proliferazione clonale incontrollata favorendo delle mitosi aberranti. I risultati di questo studio rappresentano un’importante scoperta dal punto di vista clinico, per la diagnosi e il trattamento dei pazienti con questo tipo di tumore.