Stem cell tracking with nanoparticles for regenerative medicine purposes: An overview

Accurate and noninvasive stem cell tracking is one of the most important needs in regenerative medicine to determine both stem cell destinations and final differentiation fates, thus allowing a more detailed picture of the mechanisms involved in these therapies. Given the great importance and advances in the field of nanotechnology for stem cell imaging, currently, several nanoparticles have become standardized products and have been undergoing fast commercialization. This review has been intended to summarize the current use of different engineered nanoparticles in stem cell tracking for regenerative medicine purposes, in particular by detailing their main features and exploring their biosafety aspects, the first step for clinical application. Moreover, this review has summarized the advantages and applications of stem cell tracking with nanoparticles in experimental and preclinical studies and investigated present limitations for their employment in the clinical setting

Persistent DNA damage-induced premature senescence alters the functional features of human bone marrow mesenchymal stem cells

Human mesenchymal stem cells (hMSCs) are adult multipotent stem cells located in various tissues, including the bone marrow. In contrast to terminally differentiated somatic cells, adult stem cells must persist and function throughout life to ensure tissue homeostasis and repair. For this reason, they must be equipped with DNA damage responses able to maintain genomic integrity while ensuring their lifelong persistence. Evaluation of hMSC response to genotoxic insults is of great interest considering both their therapeutic potential and their physiological functions. This study aimed to investigate the response of human bone marrow MSCs to the genotoxic agent Actinomycin D (ActD), a well-known anti-tumour drug. We report that hMSCs react by undergoing premature senescence driven by a persistent DNA damage response activation, as hallmarked by inhibition of DNA synthesis, p21 and p16 protein expression, marked Senescent Associated β-galactosidase activity and enlarged γH2AX foci co-localizing with 53BP1 protein. Senescent hMSCs overexpress several senescence-associated secretory phenotype (SASP) genes and promote motility of lung tumour and osteosarcoma cell lines in vitro. Our findings disclose a multifaceted consequence of ActD treatment on hMSCs that on the one hand helps to preserve this stem cell pool and prevents damaged cells from undergoing neoplastic transformation, and on the other hand alters their functional effects on the surrounding tissue microenvironment in a way that might worsen their tumour-promoting behaviour

Human mesenchymal stem cells labelled with dye-loaded amorphous silica nanoparticles: long-term biosafety, stemness preservation and traceability in the beating heart

Treatment of myocardial infarction with mesenchymal stem cells (MSCs) has proven beneficial effects in both animal and clinical studies. Engineered silica nanoparticles (SiO2-NPs) have been extensively used as contrast agents in regenerative medicine, due to their resistance to degradation and ease of functionalization. However, there are still controversies on their effective biosafety on cellular systems. In this perspective, the aims of the present study are: 1) to deeply investigate the impact of amorphous 50 nm SiO2-NPs on viability and function of human bone marrow-derived MSCs (hMSCs); 2) to optimize a protocol of harmless hMSCs labelling and test its feasibility in a beating heart model. Optimal cell labelling is obtained after 16 h exposure of hMSCs to fluorescent 50 nm SiO2-NPs (50 µg mL(-1)); interestingly, lysosomal activation consequent to NPs storage is not associated to oxidative stress. During prolonged culture hMSCs do not undergo cyto- or genotoxicity, preserve their proliferative potential and their stemness/differentiation properties. Finally, the bright fluorescence emitted by internalized SiO2-NPs allows both clear visualization of hMSCs in normal and infarcted rat hearts and ultrastructural analysis of cell engraftment inside myocardial tissue. Overall, 50 nm SiO2-NPs display elevated compatibility with hMSCs in terms of lack of cyto- and genotoxicity and maintenance of important features of these cells. The demonstrated biosafety, combined with proper cell labelling and visualization in histological sections, make these SiO2-NPs optimal candidates for the purpose of stem cell tracking inside heart tissue

Entre la incertidumbre y la esperanza: reflexiones y relatos globales en torno al Sars-CoV-2 (Covid-19)

Sars-Cov-2, Covid-19, coronavirus, o simplemente "la pandemia" son probablemente los términos más utilizados en los últimos meses en todo el mundo. Todos ellos se refieren a una misma situación, aunque narrada desde distintos puntos de vista. Esta publicación, con diversidad de voces, quiere dar una visión panorámica de la compleja situación mundial. En nueve ensayos académicos provenientes de Ecuador, Bélgica, España, México y Brasil, se analiza la crisis sanitaria del Sars-Cov-2 desde el punto de vista político, económico, social o ecológico

A New Paradigm in Cardiac Regeneration: The Mesenchymal Stem Cell Secretome

The potentialities to apply mesenchymal stem cells (MSCs) in regenerative medicine have been extensively studied over the last decades. In the cardiovascular disease (CVD) field, MSCs-based therapy is the subject of great expectations. Its therapeutic potential has been already shown in several preclinical models and both the safety and efficacy of MSCs-based therapy are being evaluated in humans. It is now clear that the predominant mechanism by which MSCs participate in heart tissue repair is through a paracrine activity. Via the production of a multitude of trophic factors endowed with different properties, MSCs can reduce tissue injury, protect tissue from further adverse effects, and enhance tissue repair. The present review discusses the current understanding of the MSCs secretome as a therapy for treatment of CVD. We provide insights into the possible employment of the MSCs secretome and their released extracellular vesicles as novel approaches for cardiac regeneration that would have certain advantages over injection of living cells

Valutazione del rischio di trattamenti illeciti nel bovino da carne con desametasone mediante l\u2019impiego di cortisolo e 6beta-idrossicortisolo in campioni di urina

Il 6beta-idrossicortisolo (6betaOH-F) nell\u2019uomo e in molti animali tra cui il bovino, \ue8 uno dei metaboliti del cortisolo (F) prodotti a livello epatico. Il 6betaOH-F \ue8 escreto nelle urine in forma non coniugata e rappresenta l\u20191% del totale dei metaboliti del cortisolo nell\u2019uomo (Galteau et al., 2003). Ged et al. (1989) furono i primi a dimostrare che la trasformazione del cortisolo in 6betaOH-F \ue8 catalizzata dal CYP3A e quindi il monitoraggio della sua concentrazione urinaria pu\uf2 essere utilizzato come marker in vivo dell\u2019induzione e dell\u2019inibizione delle isoforme CYP3A (Galteau et al., 2003). L\u2019urina \ue8 una matrice molto complessa, la cui composizione, le propriet\ue0 chimico-fisiche ed anche le concentrazioni di biomarcatori fisiologici possono essere influenzate nella stessa specie bovina da fattori quali l\u2019alimentazione, l\u2019et\ue0 e le condizioni di stabulazione ed anche eventuali trattamenti farmacologici. L\u2019urina \ue8 una matrice che pu\uf2 essere facilmente raccolta in allevamento, senza causare situazioni stressanti per gli animali, e congelata pu\uf2 essere conservata per tempi relativamente lunghi. I meccanismi che regolano la liberazione di F endogeno sono molto articolati. Le modalit\ue0 di regolazioni caratteristiche dell\u2019asse ipotalamo \u2013 ipofisi - surrene (HPA) sono tre: - il ritmo circadiano della steroidogenesi basale; - l\u2019incremento della steroidogenesi in risposta allo stress (Schimmer et al., 2006). - la regolazione a feedback negativo da parte dei corticosteroidi surrenalici. Quindi le variazioni di cortisolo e del suo metabolita possono dare delle indicazioni di eventuali trattamenti con corticosteroidi. Inoltre una volta valutate separatamente le concentrazioni di F e del suo metabolita 6betaOH-F il rapporto tra 6betaOH-F e cortisolo permette di normalizzare eventuali differenze di produzione di 6betaOH-F dovute alle variazioni del ritmo circadiano e alla variabilit\ue0 individuale (Ohno et al., 2000). Nella prima fase del lavoro i campioni di urina raccolti dai vitelli appartenenti ai diversi gruppi sperimentali sono stati analizzati al fine di determinare la concentrazione urinaria di cortisolo (F) e 6beta-idrossicortisolo (6betaOH-F) utilizzando un metodo RIA e un metodo ELISA, rispettivamente. Prima di passare all\u2019esecuzione delle indagini sui vari gruppi sottoposti a trattamenti \ue8 stato necessario procedere alla validazione dei due metodi utilizzati (RIA e ELISA) con urine di vitelli prelevati da animali controllo quindi non trattate e filtrate su carbone attivo per valutare adeguatamente le performance dei metodi applicati utilizzando il protocollo messo a punto da Simontacchi et al. (1997). Il pattern di escrezione urinaria del cortisolo e del suo metabolita negli animali trattati sperimentalmente con desametazone, identificato attraverso l\u2019utilizzo dei test di screening RIA ed ELISA, \ue8 stato successivamente confermato mediante analisi in spettrometria di massa (LC-MS/MS). La concordanza dei risultati ha dimostrato che cortisolo e 6beta-idrossicortisolo possono essere considerati efficaci marcatori di trattamento illecito con desametazone. Infatti l\u2019effetto della loro ridotta escrezione nelle urine \ue8 pi\uf9 duraturo della eliminazione di desametazone somministrato, quindi rappresenta un valido supporto nell\u2019indagine preliminare per la valutazione dei trattamenti illeciti in allevamento. In particolare il contenuto urinario di cortisolo, \ue8 risultato il parametro caratterizzato da maggior capacit\ue0 discriminante; la sua valutazione mediante test RIA consente di eseguire piani di sorveglianza conoscitivi in allevamento, su larga scala con costi contenut

Marker urinari indiretti dell'uso non autorizzato di corticosteroidi nel bovino da carne

In a preliminary study the reduced urine excretion of cortisol (F) and 6β-hydroxycortisol (6βOH-F) in cattle treated per os with low doses of dexamethasone (DEX) was proved. To assess the potential of these parameters as indirect markers of illegal use of corticosteroids, the concentration of F and of 6βOH-F were evaluated (by RIA and by ELISA, respectively) in urine samples collected from 40 beef cattle at the slaughterhouse. Four animals were considered to be suspected for corticosteroid treatments as F concentration in urine was below the cut-off value of 1 ng/mL