Native characterization and QC profiling of human amniotic mesenchymal stromal cell vesicular fractions for secretome-based therapy.

Human amniotic mesenchymal stromal cells (hAMSCs) have unique immunomodulatory properties making them attractive candidates for regenerative applications in inflammatory diseases. Most of their beneficial properties are mediated through their secretome. The bioactive factors concurring to its therapeutic activity are still unknown. Evidence suggests synergy between the two main components of the secretome, soluble factors and vesicular fractions, pivotal in shifting inflammation and promoting self-healing. Biological variability and the absence of quality control (QC) protocols hinder secretome-based therapy translation to clinical applications. Moreover, vesicular secretome contains a multitude of particles with varying size, cargos and functions whose complexity hinders full characterization and comprehension. This study achieved a significant advancement in secretome characterization by utilizing native, FFF-based separation and characterizing extracellular vesicles derived from hAMSCs. This was accomplished by obtaining dimensionally homogeneous fractions then characterized based on their protein content, potentially enabling the identification of subpopulations with diverse functionalities. This method proved to be successful as an independent technique for secretome profiling, with the potential to contribute to the standardization of a qualitative method. Additionally, it served as a preparative separation tool, streamlining populations before ELISA and LC-MS characterization. This approach facilitated the categorization of distinctive and recurring proteins, along with the identification of clusters associated with vesicle activity and functions. However, the presence of proteins unique to each fraction obtained through the FFF separation tool presents a challenge for further analysis of the protein content within these cargoes.

The Truth Is Out There: Biological Features and Clinical Indications of Extracellular Vesicles from Human Perinatal Stem Cells.

The potential of perinatal tissues to provide cellular populations to be used in different applications of regenerative medicine is well established. Recently, the efforts of researchers are being addressed regarding the evaluation of cell products (secreted molecules or extracellular vesicles, EVs) to be used as an alternative to cellular infusion. The data regarding the effective recapitulation of most perinatal cells' properties by their secreted complement point in this direction. EVs secreted from perinatal cells exhibit key therapeutic effects such as tissue repair and regeneration, the suppression of inflammatory responses, immune system modulation, and a variety of other functions. Although the properties of EVs from perinatal derivatives and their significant potential for therapeutic success are amply recognized, several challenges still remain that need to be addressed. In the present review, we provide an up-to-date analysis of the most recent results in the field, which can be addressed in future research in order to overcome the challenges that are still present in the characterization and utilization of the secreted complement of perinatal cells and, in particular, mesenchymal stromal cells.

Facing the Challenges in the COVID-19 Pandemic Era: From Standard Treatments to the Umbilical Cord-Derived Mesenchymal Stromal Cells as a New Therapeutic Strategy.

Coronavirus disease 2019 (COVID-19), the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which counts more than 650 million cases and more than 6.6 million of deaths worldwide, affects the respiratory system with typical symptoms such as fever, cough, sore throat, acute respiratory distress syndrome (ARDS), and fatigue. Other nonpulmonary manifestations are related with abnormal inflammatory response, the "cytokine storm", that could lead to a multiorgan disease and to death. Evolution of effective vaccines against SARS-CoV-2 provided multiple options to prevent the infection, but the treatment of the severe forms remains difficult to manage. The cytokine storm is usually counteracted with standard medical care and anti-inflammatory drugs, but researchers moved forward their studies on new strategies based on cell therapy approaches. The perinatal tissues, such as placental membranes, amniotic fluid, and umbilical cord derivatives, are enriched in mesenchymal stromal cells (MSCs) that exert a well-known anti-inflammatory role, immune response modulation, and tissue repair. In this review, we focused on umbilical-cord-derived MSCs (UC-MSCs) used in in vitro and in vivo studies in order to evaluate the weakening of the severe symptoms, and on recent clinical trials from different databases, supporting the favorable potential of UC-MSCs as therapeutic strategy.

Current Perspectives on Adult Mesenchymal Stromal Cell-Derived Extracellular Vesicles: Biological Features and Clinical Indications.

Extracellular vesicles (EVs) constitute one of the main mechanisms by which cells communicate with the surrounding tissue or at distance. Vesicle secretion is featured by most cell types, and adult mesenchymal stromal cells (MSCs) of different tissue origins have shown the ability to produce them. In recent years, several reports disclosed the molecular composition and suggested clinical indications for EVs derived from adult MSCs. The parental cells were already known for their roles in different disease settings in regulating inflammation, immune modulation, or transdifferentiation to promote cell repopulation. Interestingly, most reports also suggested that part of the properties of parental cells were maintained by isolated EV populations. This review analyzes the recent development in the field of cell-free therapies, focusing on several adult tissues as a source of MSC-derived EVs and the available clinical data from in vivo models.

Flavonoids against the SARS-CoV-2 induced inflammatory storm.

The disease severity of COVID-19, especially in the elderly and patients with co-morbidities, is characterized by hypercytokinemia, an exaggerated immune response associated with an uncontrolled and excessive release of proinflammatory cytokine mediators (cytokine storm). Flavonoids, important secondary metabolites of plants, have long been studied as therapeutic interventions in inflammatory diseases due to their cytokine-modulatory effects. In this review, we discuss the potential role of flavonoids in the modulation of signaling pathways that are crucial for COVID-19 disease, particularly those related to inflammation and immunity. The immunomodulatory ability of flavonoids, carried out by the regulation of inflammatory mediators, the inhibition of endothelial activation, NLRP3 inflammasome, toll-like receptors (TLRs) or bromodomain containing protein 4 (BRD4), and the activation of the nuclear factor erythroid-derived 2-related factor 2 (Nrf2), might be beneficial in regulating the cytokine storm during SARS-CoV-2 infection. Moreover, the ability of flavonoids to inhibit dipeptidyl peptidase 4 (DPP4), neutralize 3-chymotrypsin-like protease (3CLpro) or to affect gut microbiota to maintain immune response, and the dual action of angiotensin-converting enzyme 2 (ACE-2) may potentially also be applied to the exaggerated inflammatory responses induced by SARS-CoV-2. Based on the previously proven effects of flavonoids in other diseases or on the basis of newly published studies associated with COVID-19 (bioinformatics, molecular docking), it is reasonable to assume positive effects of flavonoids on inflammatory changes associated with COVID-19. This review highlights the current state of knowledge of the utility of flavonoids in the management of COVID-19 and also points to the multiple biological effects of flavonoids on signaling pathways associated with the inflammation processes that are deregulated in the pathology induced by SARS-CoV-2. The identification of agents, including naturally occurring substances such as flavonoids, represents great approach potentially utilizable in the management of COVID-19. Although not clinically investigated yet, the applicability of flavonoids against COVID-19 could be a promising strategy due to a broad spectrum of their biological activities.

Energy Metabolism Analysis of Three Different Mesenchymal Stem Cell Populations of Umbilical Cord Under Normal and Pathologic Conditions.

Human umbilical cord mesenchymal stem cells (hUC-MSCs) are a pivotal source of therapeutically active cells for regenerative medicine due to their multipotent differentiation potential, immunomodulatory and anti-inflammatory proprieties, as well as logistical collection advantages without ethical concerns. However, it remains poorly understood whether MSCs from different compartments of the human umbilical cord are therapeutically superior than others. In this study, MSCs were isolated from Wharton's jelly (WJ-MSCs), perivascular region (PV-MSCs) and cord lining (CL-MSCs) of hUC. These cells expressed the mesenchymal markers (CD90, CD73), stemness marker (OCT4), endothelial cell adhesion molecular marker (CD146), and the monocyte/macrophage marker (CD14) found within the MSC population implicated as a key regulator of inflammatory responses to hypoxia, was displayed by WJ-, PV-, and CL-MSCs respectively. A direct consequence of oxygen and glucose deprivation during stroke and reperfusion is impaired mitochondrial function that contributes to cellular death. Emerging findings of mitochondria transfer provide the basis for the replenishment of healthy mitochondria as a strategy for the treatment of stroke. Cell Energy Phenotype and Mito Stress tests were performed the energy metabolic profile of the three MSC populations and their mitochondrial function in both ambient and OGD cell culture conditions. PV-MSCs showed the highest mitochondrial activity. CL-MSCs were the least affected by OGD/R condition, suggesting their robust survival in ischemic environment. In this study, MSC populations in UC possess comparable metabolic capacities and good survival under normal and hypoxic conditions suggesting their potential as transplantable cells for mitochondrial-based stem cell therapy in stroke and other ischemic diseases.

Wharton's Jelly Mesenchymal Stromal Cells from Human Umbilical Cord: a Close-up on Immunomodulatory Molecules Featured In Situ and In Vitro.

Therapeutic options for end-stage organ failure are often limited to whole organ transplantation. The tolerance or rejection of the transplanted organ is driven by both early non-specific innate and specific adaptive responses. The use of mesenchymal stromal cells (MSCs) is considered a promising tool in regenerative medicine. Human umbilical cord (HUC) is an easily available source of MSCs, without relevant ethical issues. Moreover, Wharton's jelly-derived MSCs (WJ-MSCs), showed consistent immunomodulatory features that may be useful to promote immune tolerance in the host after transplantation. Few data are available on the phenotype of WJ-MSCs in situ. We investigated the expression of immune-related molecules, such as HLAs, IDO, CD276/B7-H3, and others, both in situ (HUC) and in in vitro-cultured WJ-MSCs. Morphological and biochemical techniques were used to define the expression of such molecules. In addition, we focused on the possible role of CD276/B7-H3 on T cells proliferation inhibition. We assessed CD276/B7-H3 expression by WJ-MSCs both in situ and alongside cell culture. WJ-MSCs were able to suppress T cell proliferation in mixed lymphocyte reaction (MLR). Moreover, we describe for the first time a specific role for CD276/B7-H3, since the immunomodulatory ability of WJ-MSCs was abolished upon anti-CD276/B7-H3 antibody addition to the MLR. These results further detail the immune regulation properties and tolerance induction exerted by human WJ-MSCs, in particular pointing to CD276/B7-H3 as one of the main involved factors. These data further suggest WJ-MSCs as potent tools to modulate local immune response in "support-type" regenerative medicine approaches.

The effect of Betanin parenteral pretreatment on Jejunal and pulmonary tissue histological architecture and inflammatory response after Jejunal ischemia-reperfusion injury.

Intestinal ischemic-reperfusion (IR) injury has detrimental effects on both local and distant organs in the body. Betanin is known for its antioxidant properties, and it is found mostly in vegetables. Therefore, the aim of the present study was to test the hypothesis that betanin administration prior intestinal IR, may be beneficial in protecting jejunal mucosa and lung parenchyma against IR damage. Male specific pathogen-free Charles River Wistar rats were used (n = 42). Betanin (50 mg/kg) was administered intraperitoneally 30 min before ischemia of the superior mesenteric artery lasting 1 h, followed by 1, 4 and 24 h of reperfusion. Immunohistochemical as well as histomorphometrical analysis indicated a protective effect of betanin pretreatment on jejunal tissue. Regarding morphometrical analysis betanin significantly (p < 0.01) augments intestinal villus height after 24 of reperfusion comparing to early stages. Betanin application reduced number of mast cells population in early reperfusion periods (p < 0.05). The protective effect of betanin on lung parenchyma, was detected in late reperfusion period (24 h) with improvement of histopathological injury index and morphometric analysis (p < 0.001 for both). The improvement of histopathological injury index (p < 0.001) and morphometric analysis (p < 0.001) during the late reperfusion period, suggests a protective effect of betanin on lung parenchyma. Moreover, suppression of the inflammatory response was mirrored by the reduction of myeloperoxidase (MPO) positive cells within lung parenchyma after 1 and 4 h of reperfusion (p < 0.001). Especially, during the first 4 h of reperfusion after betanin administration, a reduction of 74% of the polymorphonuclear neutrophils infiltration (MPO positive cell population) and of a nearly 46% of active MCs was observed. Upon morphometric examination, the lung histological architecture after 24 h of reperfusion appeared to be almost 100% better following betanin treatment, with 25% thinner interalveolar septa and 20% larger alveolar surface for respiratory gas exchange. The results suggest that betanin pretreatment protects the jejunal mucosa and the lung parenchyma, as well as reduces the inflammatory cell density after intestinal IR injury.

Wharton's Jelly Mesenchymal Stromal Cells Support the Expansion of Cord Blood-derived CD34+ Cells Mimicking a Hematopoietic Niche in a Direct Cell-cell Contact Culture System.

Wharton's jelly mesenchymal stromal cells (WJ-MSCs) have been recently exploited as a feeder layer in coculture systems to expand umbilical cord blood-hematopoietic stem/progenitor cells (UCB-HSPCs). Here, we investigated the role of WJ-MSCs in supporting ex vivo UCB-HSPC expansion either when cultured in direct contact (DC) with WJ-MSCs or separated by a transwell system or in the presence of WJ-MSC-conditioned medium. We found, in short-term culture, a greater degree of expansion of UCB-CD34+ cells in a DC system (15.7 ± 4.1-fold increase) with respect to the other conditions. Moreover, in DC, we evidenced two different CD34+ cell populations (one floating and one adherent to WJ-MSCs) with different phenotypic and functional characteristics. Both multipotent CD34+/CD38- and lineage-committed CD34+/CD38+ hematopoietic progenitors were expanded in a DC system. The former were significantly more represented in the adherent cell fraction than in the floating one (18.7 ± 11.2% vs. 9.7 ± 7.9% over the total CD34+ cells). Short-term colony forming unit (CFU) assays showed that HSPCs adherent to the stromal layer were able to generate a higher frequency of immature colonies (CFU-granulocyte/macrophage and burst-forming unit erythroid/large colonies) with respect to the floating cells. In the attempt to identify molecules that may play a role in supporting the observed ex vivo HSPC growth, we performed secretome analyses. We found a number of proteins involved in the HSPC homing, self-renewal, and differentiation in all tested conditions. It is important to note that a set of sixteen proteins, which are only in part reported to be expressed in any hematopoietic niche, were exclusively found in the DC system secretome. In conclusion, WJ-MSCs allowed a significant ex vivo expansion of multipotent as well as committed HSPCs. This may be relevant for future clinical applications.

Immunomodulatory effects of stem cells: Therapeutic option for neurodegenerative disorders.

Stem cells have the capability of self-renewal and can differentiate into different cell types that might be used in regenerative medicine. Neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), and amyotrophic lateral sclerosis (ALS) currently lack effective treatments. Although stem cell therapy is still on the way from bench to bedside, we consider that it might provide new hope for patients suffering with neurodegenerative diseases. In this article, we will give an overview of recent studies on the potential therapeutic use of mesenchymal stem cells (MSCs), neural stem cells (NSCs), embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), and perinatal stem cells to neurodegenerative disorders and we will describe their immunomodulatory mechanisms of action in specific therapeutic modalities.

Downregulation of myogenic microRNAs in sub-chronic but not in sub-acute model of daunorubicin-induced cardiomyopathy.

Cardiac muscle-related microRNAs play important roles in cardiac development and disease by translational silencing of mRNAs, the dominant mechanism of microRNA action. To test whether they could be involved in daunorubicin-associated cardiomyopathy (DACM), we determined expression patterns of myomiRs in two distinct models of DACM. We used 10-12 weeks old male Wistar rats. In the sub-acute model, rats were administered with six doses of daunorubicin (DAU-A, 3 mg/kg, i.p., every 48 h). Rats were sacrificed two days after the last dose. In the sub-chronic model, anaesthetized rats were administered a single dose of daunorubicin (15 mg/kg, i.v., DAU-C). Age-matched controls (CON) received vehicle. Rats were sacrificed eight weeks later. Left ventricular (LV) functions (LV pressure, rate of pressure development, +dP/dt and decline, -dP/dt) were measured using left ventricular catheterization. Expressions of myomiRs (miR-208a, miR-499, miR-1 and miR-133a), markers of cardiac failure (atrial and brain natriuretic peptides genes; Nppa and Nppb) and myosin heavy chain genes (Myh6, Myh7, Myh7b) in cardiac tissue were determined by RT-PCR. Protein expression of gp91phox NADPH oxidase subunit was detected by immunoblotting. Both DAU groups exhibited a similar depression of LV function, and LV weight reduction, accompanied by an upregulation of natriuretic peptides, and a decrease of Myh6 to total Myh ratio (-18% in DAU-A and - 25% in DAU-C, as compared to controls; both P < 0.05). DAU-C, but not DAU-A rats had a 35% mortality rate and exhibited a significantly increased gp91phox expression (DAU-C: 197 ± 33 versus CON-C: 100 ± 11; P < 0.05). Interestingly, myomiRs levels were only reduced in DAU-C compared to CON-C (miR-208: -45%, miR-499: -30%, miR-1: -29%, miR- and miR133a: -25%; all P < 0.05) but were unaltered in DAU-A. The lack of myomiRs expression, particularly in sub-chronic model, suggests the loss of control of myomiRs network on late progression of DACM. We suppose that the poor inhibition of mRNA targets might contribute to chronic DACM.

Wharton's Jelly Mesenchymal Stromal Cells as a Feeder Layer for the Ex Vivo Expansion of Hematopoietic Stem and Progenitor Cells: a Review.

In recent years, umbilical cord blood (UCB) has been widely used as an alternative source to bone marrow (BM) for transplantation of hematopoietic stem and progenitor cells (HSPCs) in a variety of hematological and non-hematological disorders. Nevertheless, the insufficient number of UCB-HSPCs for graft represents a major challenge. HSPCs ex vivo expansion prior to transplantation is a valid strategy to overcome this limit. Several attempts to optimize the expansion conditions have been reported, including the use of mesenchymal stromal cells (MSCs) as feeder layer. Wharton's Jelly (WJ), the main component of umbilical cord (UC) matrix, is especially rich in MSCs, which are considered ideal candidates for feeder layer in co-culture systems. In fact, they can be easily harvested and grow robustly in culture, producing a confluent monolayer in a short time. Similarly to bone marrow-mesenchymal stromal cells (BM-MSCs), WJ-derived MSCs (WJ-MSCs) have been used to support hematopoiesis in vitro and in vivo. Here, we review the rationale for using MSCs, particularly WJ-MSCs, as a feeder layer for UCB-HSPCs ex vivo expansion. In addition, we report the main findings attesting the use of these MSCs as a support in hematopoiesis.

Caffeine and cardiovascular diseases: critical review of current research.

Caffeine is a most widely consumed physiological stimulant worldwide, which is consumed via natural sources, such as coffee and tea, and now marketed sources such as energy drinks and other dietary supplements. This wide use has led to concerns regarding the safety of caffeine and its proposed beneficial role in alertness, performance and energy expenditure and side effects in the cardiovascular system. The question remains "Which dose is safe?", as the population does not appear to adhere to the strict guidelines listed on caffeine consumption. Studies in humans and animal models yield controversial results, which can be explained by population, type and dose of caffeine and low statistical power. This review will focus on comprehensive and critical review of the current literature and provide an avenue for further study.

Hsp10 nuclear localization and changes in lung cells response to cigarette smoke suggest novel roles for this chaperonin.

Heat-shock protein (Hsp)10 is the co-chaperone for Hsp60 inside mitochondria, but it also resides outside the organelle. Variations in its levels and intracellular distribution have been documented in pathological conditions, e.g. cancer and chronic obstructive pulmonary disease (COPD). Here, we show that Hsp10 in COPD undergoes changes at the molecular and subcellular levels in bronchial cells from human specimens and derived cell lines, intact or subjected to stress induced by cigarette smoke extract (CSE). Noteworthy findings are: (i) Hsp10 occurred in nuclei of epithelial and lamina propria cells of bronchial mucosa from non-smokers and smokers; (ii) human bronchial epithelial (16HBE) and lung fibroblast (HFL-1) cells, in vitro, showed Hsp10 in the nucleus, before and after CSE exposure; (iii) CSE stimulation did not increase the levels of Hsp10 but did elicit qualitative changes as indicated by molecular weight and isoelectric point shifts; and (iv) Hsp10 nuclear levels increased after CSE stimulation in HFL-1, indicating cytosol to nucleus migration, and although Hsp10 did not bind DNA, it bound a DNA-associated protein.

The role of intrinsic pathway in apoptosis activation and progression in Peyronie's disease.

Peyronie's disease (PD) is characterized with formation of fibrous plaques which result in penile deformity, pain, and erectile dysfunction. The aim of this study was to investigate the activation of the intrinsic apoptotic pathway in plaques from PD patients. Tunica albuginea from either PD or control patients was assessed for the expression of bax, bcl-2 and caspases 9 and 3 using immunohistochemistry and by measurement of apoptotic cells using TUNEL assay. Bax overexpression was observed in metaplastic bone tissue, in fibroblasts, and in myofibroblast of plaques from PD patients. Little or no bcl-2 immunostaining was detected in samples from either patients or controls. Caspase 3 immunostaining was very strong in fibrous tissue, in metaplasic bone osteocytes, and in primary ossification center osteoblasts. Moderate caspase 9 immunostaining was seen in fibrous cells plaques and in osteocytes and osteoblasts of primary ossification centers from PD patients. Control samples were negative for caspase 9 immunostaining. In PD patients the TUNEL immunoassay showed intense immunostaining of fibroblasts and myofibroblasts, the absence of apoptotic cells in metaplasic bone tissue and on the border between fibrous and metaplastic bone tissue. Apoptosis occurs in stabilized PD plaques and is partly induced by the intrinsic pathway.

Umbilical cord revisited: from Wharton's jelly myofibroblasts to mesenchymal stem cells.

The umbilical cord (UC) is an essential part of the placenta, contributing to foetal development by ensuring the blood flow between mother and foetus. The UC is formed within the first weeks of gestation by the enclosure of the vessels (one vein and two arteries) into a bulk of mucous connective tissue, named Wharton's jelly (WJ) and lined by the umbilical epithelium. Since their first identification, cells populating WJ were described as unusual fibroblasts (or myofibroblasts). Recent literature data further highlighted the functional interconnection between UC and the resident cells. The UC represents a reservoir of progenitor populations which are collectively grouped into MSCs (mesenchymal stem cells). Such cells have been sourced from each component of the cord, namely the sub-amnion layer, the WJ, the perivascular region, and the vessels. These cells mainly show adherence to the phenotype of adult MSCs (as bone marrow-derived ones) and can differentiate towards mature cell types belonging to all the three germ layers. In addition, cells from human UC are derived from an immunoprivileged organ, namely the placenta: in fact, its development and function depend on the elusion of the maternal immune response towards the semi-allogeneic embryo. This is reflected in the expression of immunomodulatory molecules by UC-derived MSCs. The present paper describes UC structural features and the cell types which can be derived, with a focus on their phenotype and the novel results which boosted the use of UC-derived cells for regenerative medicine applications.

Hsp10: anatomic distribution, functions, and involvement in human disease.

There is growing evidence that molecular chaperones/heat shock proteins are involved in the pathogenesis of a number of human diseases, known as chaperonopathies. A better molecular understanding of the pathogenetic mechanisms is essential for addressing new strategies in diagnostics, therapeutics and clinical management of chaperonopathies, including those in which Hsp10 is involved. This chaperonin has been studied for a long time as a member of the mitochondrial protein-folding machine. However, although in normal cells Hsp10 is mainly localized in the mitochondrial matrix, it has also been found during and after stress in other subcellular compartments, such as cytosol, vesicles and secretory granules, alone or in combination with other proteins. In these extramitochondrial locales, Hsp10 plays an active role in cell signalling. For example, cancer cells often show altered levels of Hsp10, compared to normal cells. Hsp10 may also be found in the extracellular space and in the bloodstream, with a possible immunomodulatory activity. This minireview focuses on some studies to date on the involvement of Hsp10 in human disease pathogenesis.

Human Wharton's jelly mesenchymal stem cells maintain the expression of key immunomodulatory molecules when subjected to osteogenic, adipogenic and chondrogenic differentiation in vitro: new perspectives for cellular therapy.

Rheumatoid arthritis and osteoarthritis are the main diseases that imply an inflammatory process at the joints involving the articular cartilage. Recently, mesenchymal stem cells (MSCs) derived from perinatal tissues were considered good candidates for cellular therapy of musculoskeletal and orthopaedic diseases, since they can differentiate into multiple cell types and are an easily accessible cellular source. Therefore, several protocols exist on the differentiation of mesenchymal stem cells of different origins into osteoblasts and chondrocytes. Another key feature of MSCs is their capacity to modulate the immune system responses in vitro and in vivo. This may have critical outcomes in diseases of the musculoskeletal system where an inflammatory or autoimmune process is at the basis of the main disease. In the present paper, after isolation of MSCs from Wharton's Jelly (WJ-MSCs), we performed the three standard differentiation protocols. The acquisition of the differentiated phenotype was demonstrated by the specific histological stains. As the main objective of this work, we determined the expression of immunomodulatory molecules (by immunohistochemistry and qualitative RT-PCR), both in undifferentiated cells and after differentiation. We demonstrated for the first time that immune-related molecules (as B7-H3/CD276 and HLA-E) which have been characterized in undifferentiated MSCs, are also expressed by the differentiated progeny. This strongly suggests that also after the acquisition of a mature phenotype, WJ-MSCs-derived cells may maintain their immune privilege. This evidence, which deserves much work to be confirmed in vivo and in other MSCs populations, may provide a formal proof of the good results globally achieved with WJMSCs as cellular therapy vehicle.

New frontiers in regenerative medicine in cardiology: the potential of Wharton's jelly mesenchymal stem cells.

Cardiomyopathies are still the first cause of death in the world. The identification of resident stem cells, comprising those derived from sub-endocardial stroma, suggests the possible self regeneration of the heart under autocrine/paracrine modulation in the cardiac microenvironment. Nevertheless, because of the limited in vivo regeneration potential of damaged cardiac tissue, the use of drugs and ultimately cardiac transplantation remain the common treatments of heart diseases and defects. The differentiative potential of embryonic and mesenchymal stem cells (MSCs) derived from different tissues (such as bone marrow and adipose tissue) was extensively explored in cell therapy for regenerative medicine. Many groups have been focused, in recent years, on isolation, characterization, and differentiation potential of MSCs derived from perinatal (or extraembryonic) tissues, mainly the placenta and the human umbilical cord. In this review, we summarized recent works about the stemness of Wharton's jelly stromal cells and their potential in cardiac regeneration with favourable use in cell therapy and regenerative medicine. The peculiar features of these cells, as the expression of cardiac-specific transcription factors and immunomodulatory molecules suggest that human umbilical cord may be considered as a reliable alternative source of MSC useful for advanced therapy in cardiac regenerative medicine.