Search

This chapter focuses on the immunomodulatory properties of placental mesenchymal stromal cells (MSCs) derived from the amniotic membrane, umbilical cord, and chorionic villi. Within the amniotic membrane (AM), we discuss the immunomodulatory properties of the two main cell populations that can be isolated from AM: human amniotic mesenchymal stromal cells (hAMSCs) and human amniotic epithelial cells (hAECs). Within the umbilical cord, several compartments have been described, including the amniotic compartment, the Wharton’s jelly (WJ) compartment, and the vascular and perivascular compartment, but herein attention is focused on the properties of human WJ MSCs (hWJMSCs). Since different isolation protocols have been used, umbilical cord matrix stem cells, umbilical cord stromal cells, and human umbilical cord MSCs (herein hUCMSCs) were also included. This chapter also discusses the properties of human chorionic villi/placenta MSCs (hCVMSCs/hPLMSCs). The nomenclature of placental MSCs used in this chapter was chosen on the basis of consensus from the First International Workshop on Placenta-Derived Stem Cells for hAECs and hAMSCs (Parolini et al. 2008). Since different nomenclature is reported for the other placental MSCs, the following nomenclature is used: hWJMSCs/hUCMSCs for MSCs from WJ (and from umbilical cord where described isolation protocols include WJ) and hCVMSCs/hPLMSCs for MSCs from chorionic villi and the placenta/trophoblast compartment.

Perinatal stem cells research attracted great interest worldwide in recent years. Foetus-associated tissues contain various populations of stem cells, most of which are comprised within the category of mesenchymal stem cells (MSCs). This special issue collects both reviews and original reports on all the perinatal stem cell types which are currently under investigation. These cells have multiple promising features: differentiative capacity towards mature cell types of all the three germ layers, hypoimmunogenicity in vitro and in vivo, ease of sourcing, ex vivo culture and stor- age. In particular, immune modulation is viewed as a prom- ising feature of many MSCs populations, since these cells, once administered therapeutically, may be able to overcome, or at least evade, the host immune response which may lead to acute or chronic rejection of the transplant .

Endothelial cells are key modulators of diverse physiological processes, and their impaired function is a cause of numerous cardiovascular diseases. Under physiologic condition, the reactive oxygen and nitrogen mediators in endothelia lead to the signal propagation of the initial stimulus, by forming molecules with a longer half-life like hydrogen peroxide. Hydrogen peroxide is the focus of growing attention in endothelial biology, and consequently the enzymes involved in its generation and clearance are viewed as novel mediators of great importance. In particular, among peroxidases, myeloperoxidase is recognized as a key enzyme, capable of impairing intracellular NO reservoirs as well as producing oxidized amino acids such as 3-chlorotyrosine or 3-nitrotyrosine. This process switches the functional pathways from normal signalling to a condition characterized by oxidative and/or nitrosative stress. Understanding the molecular mechanisms involved in these stress responses in endothelium will lead to better therapeutic strategies for oxidative stress-driven cardiovascular diseases.

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.

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.

Stenosi del giunto pielo-ureterale, biomarcatori urinari, fibrosi, funzione renale, matrice extracellulare.

Endothelial cells are key modulators of multiple physiological processes, and their impairment may result in the generation of endothelial dysfunction and ultimately cardiovascular diseases. Under physiologic conditions, reactive oxygen and nitrogen mediators of endothelial cells act to propagate signals driven by different stimuli, by forming molecules with a longer half-life like hydrogen peroxide. Reactive oxygen species (ROS) are constantly produced as a consequence of aerobic metabolism. Under physiologic conditions, their tendency to cause oxidative damage is counterbalanced by the action of antioxidants or oxidant-scavenging enzymes. An imbalance in favour of oxidants leads to oxidative stress, which can result in cardiomyocyte apoptosis and reduced bioavailability of vascular nitric oxide (NO). Together, these processes may lead to altered vasodilatation of the coronary, pulmonary and peripheral vascular beds. Myeloperoxidase is a key enzyme, capable of impairing intracellular NO reservoirs as well as producing oxidized amino acids such as 3-chlorotyrosine or 3-nitrotyrosine. Recent literature data have shown that apart neutrophils, this enzyme may be expressed by other cell types, and remarkably by endothelial cells both in vitro and in vivo, as a consequence of the exposure to oxidative stress. In this review we analyze recent literature and patents related to the detection, quantification and role of myeloperoxidase as a biomarker in patients affected by chronic heart failure or other cardiovascular diseases. A particular focus is given to analytical approaches aimed to detect early signals of variations in ROS or related enzymes or their by-products, via serological or other low-invasivity assays. The developments in this field may constitute a key improvement of the ability to manage and treat patients suffering from CHF as well as allowing to elucidate the molecular mechanisms behind the clinical phenomena.

End-stage liver diseases are one of the leading causes of death in the world. Often orthotopic liver transplantation represents the final therapeutic choice. The limits of this approach are the scarcity of donor livers available, and the many side effects related to the administration of immune suppressants to the patients. Cellular therapy for liver diseases is increasingly being viewed as a promising strategy to provide hepatocytes to replenish the parenchymal cells of the organ. This technique suffers of some important limitations, such as the difficulty in isolating sufficient cell numbers (e.g. when adult or foetal hepatocytes are used for transplantation), the limited viability of isolated hepatocytes and, when applicable, the limited differentiation of stem cells (when hepatocyte-like cells are derived from hepatic or extra-hepatic progenitor populations). In recent years, perinatal stem cells have been proposed as reliable cellular populations which may be successfully used to derive hepatocyte-like cells. These cells feature key advantages over other adult stem cells: may be easily sourced from the tissues of origin, can be expanded ex vivo to obtain high cell numbers, may be differentiated towards hepatocyte-like cells. In addition, these cells feature relevant immunomodulatory and anti-inflammatory activities, and their sourcing is not limited by ethical concerns In the present review we analyze the molecular basis of hepatocyte biology and development, and discuss the recent advances in deriving hapatocyte-like cells from perinatal stem cells. Very recent papers on mesenchymal stem cells derived from bone marrow and adipose tissues are also comparatively discussed as prototypes of the use of adult extrahepatic stem cells. In our opinion, perinatal stem cells do represent a promising tool for liver regenerative medicine, and recent research reports further strengthened this perception and fostered further efforts by multiple research groups worldwide.

Mesenchymal stem cells (MSCs) are virtually present in all postnatal organs as well as in perinatal tissues. MSCs can be differentiated toward several mature cytotypes and interestingly hold potentially relevant immunomodulatory features. Myocardial infarction results in severe tissue damage, cardiomyocyte loss, and eventually heart failure. Cellular cardiomyoplasty represents a promising approach for myocardial repair. Clinical trials using MSCs are underway for a number of heart diseases, even if their outcomes are hampered by low long-term improvements and the possible presence of complications related to cellular therapy administration. Therefore, elucidating the presence and role of MSCs that reside in the post-infarct human heart should provide essential alternatives for therapy. In the current article we show a novel method to reproducibly isolate and culture MSCs from the subendocardial zone of human left ventricle from patients undergoing heart transplant for post-infarct chronic heart failure (HSE-MSCs, human subendocardial mesenchymal stem cells). By using both immunocytochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR), we demonstrated that these cells do express key MSCs markers and do express heart-specific transcription factors in their undifferentiated state, while lacking strictly cardiomyocyte-specific proteins. Moreover, these cells do express immunomodulatory molecules that should disclose their further potential in immune modulation processes in the post-infarct microenvironment. Another novel datum of potentially relevant interest is the expression of cardiac myosin heavy chain at nucclear level in HSE-MSCs. Standard MSCs trilineage differentiation experiments were also performed. The present paper adds new data on the basic biological features of heart-resident MSCs that populate the organ following myocardial infarction. The use of heart-derived MSCs to promote in-organ repair or as a cellular source for cardiomyoplasty is a fascinating and challenging task, which deserves further research efforts.

Mesenchymal stem cells (MSC) are uniquely capable of crossing germinative layers borders (i.e. are able to differentiate towards ectoderm-, mesoderm- and endoderm-derived cytotypes) and are viewed as promising cells for regenerative medicine approaches in several diseases. Type I diabetes therapy should potentially benefit from such differentiated cells: the search for alternatives to organ/islet transplantation strategies via stem cells differentiation is an ongoing task, significant goals having been achieved in most experimental settings (e.g. insulin production and euglycaemia restoration), though caution is still needed to ensure safe and durable effects in vivo. MSC are obtainable in high numbers via ex vivo culture and can be differentiated towards insulin-producing cells (IPC). Moreover, recent reports evidenced that MSC possess immunomodulatory activities (acting on both innate and acquired immunity effectors) which should result in a reduction of the immunogenicity of transplanted cells, thus limiting rejection. Moreover it has been proposed that MSC administration should be used to attenuate the autoimmune processes which lead to the destruction of beta cells. This review illustrates the recent advances made in differentiating human MSC to IPC. In particular, we compare the effectiveness of the differentiation protocols applied, the markers and functional assays used to characterize differentiated progeny, and the in vivo controls. We further speculate on how MSC derived from Wharton's jelly of human umbilical cord may represent a more promising regenerative medicine tool, as recently demonstrated for endoderm-derived organs (as liver) in human subjects, also considering their peculiar immunomodulatory features compared to other MSC populations.

The presence of multipotent cells in several adult and embryo-related tissues opened new paths for their use in regenerative medicine. Extraembryonic tissues such as umbilical cord are considered a promising source of stem cells, potentially useful in therapy. The characterization of cells from the umbilical cord matrix (Wharton''s Jelly) and amniotic membrane revealed the presence of a population of mesenchymal-like cells, sharing a set of core-markers expressed by "mesenchymal stem cells". Several reports enlightened the differentiation capabilities of these cells, even if at times the lack of an extensive characterization of surface markers and immune co-stimulators expression revealed hidden pitfalls when in vivo transplantation was performed. The present work describes a novel isolation protocol for obtaining mesenchymal stem cells from the umbilical cord matrix. These cells are clonogenic, retain long telomeres, can undergo several population doublings in vitro, and can be differentiated in mature mesenchymal tissues as bone and adipose. We describe for the first time that these cells, besides expressing all of the core-markers for mesenchymal stem cells, feature also the expression, at both protein and mRNA level, of tolerogenic molecules and markers of all the three main lineages, potentially important for both their differentiative potential as well as immunological features.

Mesenchymal stem cells derived from Wharton’s jelly (WJ-MSCs) recently emerged as promising tools for cellular therapy due to their ability to differentiate into diverse cell types and their immunomodulatory features. Little is known on the expression of immunomodulatory molecules in mature cells differentiated from WJ-MSCs, therefore we aimed to characterize the extent of maintenance of the naive traits of these cells also in a highly specialized differentiated counterpart. WJ-MSCs were differentiated into hepatocyte-like cells (HLCs) with a four weeks protocol. RT-PCR, flow cytometry, IHC and ICC were performed to assess expression of key markers in both undifferentiated and differentiated cells. Hepatocyte specific assays such as PAS staining, CYP3A4 induction and activity, G6Pase activity, were performed to demonstrate the acquisition of traits of the mature hepatocyte phenotype. WJ-MSCs were successfully differentiated into HLCs using a multi-step protocol. These cells were able to store glycogen, incorporate specific live cells stains, perform enzymatic reactions and metabolic activities which are usually featured by mature hepatocytes. In addition, WJ-MSCs did express several immune-related molecules, for which an immunomodulatory role has been demonstrated both in vitro and in vivo. We demonstrated for the first time that key molecules as HLA-E and B7-H3 are expressed also by HLCs derived from WJ-MSCs. Our data showed for the first time that HLCs mostly maintain the expression of immune-modulating molecules, together with new markers and functional features of mature cells. In multiple pathologic conditions the intrinsic immunomodulatory ability of differentiated cells may help survive the interaction with the host immune system, even in the absence of a specific immunosuppressive therapy. This, together with the acquisition of key mature hepatocyte functions, may render WJ-MSCs promising in cell therapy applications for liver diseases., Italian Journal of Anatomy and Embryology, Vol 119, No 1 (Supplement) 2014

Mesenchymal stem cells (MSC) constitute a variety of cellular populations which were described first about 35 years ago in the bone marrow (BM) stroma [1]. These years have foreseen an exponential increase of reports pointing out features, stemness, markers, tissue sources and clinical applications of these cells. Cells with MSC features can be isolated from virtually every adult organ in the body, as well from a group of fetus-associated sources (cells derived from the latter tissues are collectively known as perinatal stem cells) [2]. In recent years, the umbilical cord arose as a promising source of mesenchymal stem cells, which can be isolated in relatively high numbers (compared to BM) and should be further cultured and cryopreserved. Wharton’s jelly (WJ) is the main constituent of the umbilical cord. This mature mucous tissue extends from the amniotic epithelium to the perivascular zone of the cord, and contains an abundant extracellular matrix with fibroblast-like or myofibroblast-like cells inside. The high interest for new stem cell sources for the most diverse clinical applications and the amount of data accumulating on WJ-MSC, pushed for the development of this special issue [3].

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.

Chronic liver diseases constitute one of the main causes of death in western countries. Orthotopic liver transplantation still remains the final therapeutic approach to these diseases, but alternative therapeutic strategies are actively researched. Hepatocyte transplantation is considered a promising approach, even if this technique presents many limitations. These factors boosted the research for alternative cell sources to derive functional hepatocytes. In the last years, research on basic biology and differentiative ability of adult, embryonic and perinatal stem cells has constantly increased. The term "perinatal" indicates stem cell populations derived from foetal sources such as placental chorionic villi, chorion, amnion, amniotic fluid and umbilical cord. These cellular populations may differentiate towards several mature cell types, derived from all three germ layers. Multiple reports suggested that such cells can be differentiated towards hepatoblasts and hepatocyte-like cells, heralding their possible use for the treatment of inflammation, trauma and degeneration in liver disorders. In this review, we analyze the patents which were developed concerning hepatic differentiation ability of perinatal stem cells and their possible role in regenerative medicine.

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.

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.

Mesenchymal (stromal) stem cells (MSC) are a broad class of stromal populations which are able to differentiate towards mature cell types, and do express molecules involved in immune modulation, tolerance induction and inflammation dampening. MSC can be virtually isolated from each adult organ, as well as from foetus-associated perinatal tissues. In particular, Wharton's jelly-derived MSC (WJ-MSC) bear all of these key properties, together with their ease of sourcing and lack of ethical issues. Cellular therapy is a key technique in regenerative medicine approaches, in particular for the treatment of diseases in which physiological processes of cellular repopulation are blocked by the underlying pathological conditions. Recent data enlightened the ability of administered cells to act also in a repopulation-independent fashion in target organs, since their peculiar immunomodulatory and anti-inflammatory features may favor organ self-repair by reactivating local progenitors by both cell-mediated or paracrine mechanisms. Translating classical regenerative medicine to "reparative medicine" or "support medicine" should represent a further therapeutic strategy independent from the differentiation capacity of MSC populations. Recent data further highlighted that WJ-MSC outperform BM-MSC (which are now being applied clinically) both in terms of immune modulation and lack of tumorigenesis (or tumor-promoting activities) in vivo. Starting from these premises, this paper analyzes the recent data on the biology of WJ-MSC, considering the role of both naive and differentiated cells in immune modulation. In particular, the role of tolerance promoting pathways via non-classical B7 costimulators or class Ib MHC molecules are examined. In addition, we also analyzed the interconnections with other mechanicistic pathways (as those driven by matrix degrading metalloproteinases) in immune modulation. Our observations strongly support the notion that WJ-MSC may constitute a new tool in regenerative and reparative medicine applications.

BackgroundIt is increasingly clear that some heat shock proteins (Hsps) play a role in inflammation. Here, we report results showing participation of Hsp60 in the pathogenesis of chronic obstructive pulmonary diseases (COPD), as indicated by data from both in vivo and in vitro analyses.Methods and resultsBronchial biopsies from patients with stable COPD, smoker controls with normal lung function, and non-smoker controls were studied. We quantified by immunohistochemistry levels of Hsp10, Hsp27, Hsp40, Hsp60, Hsp70, Hsp90, and HSF-1, along with levels of inflammatory markers. Hsp10, Hsp40, and Hsp60 were increased during progression of disease. We found also a positive correlation between the number of neutrophils and Hsp60 levels. Double-immunostaining showed that Hsp60-positive neutrophils were significantly increased in COPD patients. We then investigated in vitro the effect on Hsp60 expression in bronchial epithelial cells (16HBE) caused by oxidative stress, a hallmark of COPD mucosa, which we induced with H₂O₂. This stressor determined increased levels of Hsp60 through a gene up-regulation mechanism involving NFkB-p65. Release of Hsp60 in the extracellular medium by the bronchial epithelial cells was also increased after H₂O₂ treatment in the absence of cell death.ConclusionsThis is the first report clearly pointing to participation of Hsps, particularly Hsp60, in COPD pathogenesis. Hsp60 induction by NFkB-p65 and its release by epithelial cells after oxidative stress can have a role in maintaining inflammation, e.g., by stimulating neutrophils activity. The data open new scenarios that might help in designing efficacious anti-inflammatory therapies centered on Hsp60 and applicable to COPD.

Introduction. Wharton’s jelly (WJ), the main constituent of umbilical cord, emerged as a reliable and uncontroversial source of mesenchymal stem cells (MSC). WJ-MSC show unique ability in crossing lineage borders, therefore being capable to trans-ifferentiate towards mature cytotypes derived from the three germ layers. As other fetal-associated cells, WJ-MSC express several immunomodulatory molecules, essential during the initial phases of human development and for the processes linked to the tolerance of the mother to the semiallogeneic embryo. Very few data are present in literature on the maintenance of the immune privilege of the naïve cells after performing differentiation. Our previous work highlighted the expression of non-classical HLA molecules as HLA-G in WJ-MSC, together with a favorable combination of B7-1 and B7-2 costimulators. Methods. The aim of this work was extending the knowledge on the expression of immunomodulatory molecules by naïve and differentiated WJ-MSC. WJ-MSC underwent differentiation to osteoblasts, adipocytes and hepatocyte-like cells. Differentiated cells were analyzed, by RT-PCR, ICC and histological stains for the acquisition of the desired phenotypical features. We investigated also the differential expression of immune-related molecules in undifferentiated and differentiated cells. Moreover, we exploited the in vitro ability of such cells to suppress allogeneic lymphocyte proliferation in MLR experiments. Results. WJ-MSC expressed diverse immunomodulatory molecules which span from non-classical type I HLAs (i.e. HLA-E, -F, -G) , to further members of the B7 family, and of the CEA superfamily, for all of which in vivo immunomodulating functions are known. For some of these factors, we demonstrated for the first time their expression in WJ-MSC. In addition, we demonstrated for the first time that the expression of these molecules is maintained after performing osteogenic, adipogenic or hepatogenic differentiation. Conclusions. Present data should disclose new promising features for the in vivo application of WJ-MSC in allogeneic cell therapy settings.

Stem cells can be found in embryonic and extraembryonic tissues as well as in adult organs. In particular, research in the last few years has delineated the key features of perinatal stem cells derived from fetus-associated tissues. These cells show multiple differentiation potential, can be easily expanded ex vivo, and raise no ethical concerns as regards their use. Several reports indicate that cells isolated from Wharton's jelly (WJ), the main component of umbilical cord extracellular matrix, are multipotent stem cells that express markers shared by other mesenchymal stem cells (MSC) and give rise to different mature cell types belonging to all three germ layers. Moreover, WJ-MSC display promising hypoimmunogenic and immunomodulatory properties, since they express molecules able to modulate NK cells and expand regulatory T-cell populations. In this review, we focus on the use of perinatal stem cells for regenerative medicine aimed at cartilage repair and regeneration. Cartilage is a specialized connective tissue which has poor regeneration and self-repair capacity in vivo. Traumatic injury or autoimmune processes are among the main causes of cartilage damage and degeneration, for which new hope comes from tissue engineering using stem cells which have undergone chondrocyte-like differentiation. We analyze the in vitro and in vivo data on the use of perinatal stem cells, in particular WJ-MSC, for cartilage regenerative medicine. The high variability of cell sources, the use of different types of scaffolds and matrixes, and the administration of several combinations of growth factors clearly point out the need for further research to optimize this cellular therapy approach and translate the results obtained from bench to clinic.

In recent years, important advances were made to clarify the biology and potential use of mesenchymal stem cells (MSC) in the therapy of a number of disorders. MSC are present in a number of tissues, ranging from adult bone marrow, to several adult organs, adipose tissue and, in the last years, the fetal-associated (also named as extraembryonic) tissues (e.g. placenta, amniotic membrane, umbilical cord). In particular, research on cells derived from mature umbilical cord, a tissue which is still discarded at birth, showed that mesenchymal stem cells can be successfully isolated from the Wharton’s jelly (WJ), the main constituent of this organ. This review will take in to account the patents which were de- veloped concerning the isolation procedures of cells from WJ (both using enzymatic or enzyme-free techniques), the de- velopment of differentiation protocols and the in vivo applications in cellular therapy approaches using both differentiated and undifferentiated cells. In addition, we will focus on the latest advances on the biology of these cells, in particular for what concerns their hypoimmunogenicity in in vitro and in vivo, and their potential application as immunomodulatory cells besides their differentiation capacity.

Mesenchymal stem cells (MSC) are considered promising tools in regenerative medicine applications. Even if they are already applied clinically, their extended characterization is being increasingly viewed as a needed feature, in order to avoid contrasting results when translating “in vitro” experiments to “in vivo” approaches. We recently demonstrated in human MSC isolated from the umbilical cord matrix (HEMSC) the expression of novel markers indicative of their stemness, as well as differentiative and immune properties [1]. HEMSC were cultured and subject to multiple molecular and morphological analyses to determine the expression of markers of interest. Undifferentiated HEMSC expressed immunoregulatory molecules, both surface antigens and secreted cytokines. In addition to the differential expression of B7 co-stimulators (CD80+/CD86-), HEMSC expressed pregnancy-specific immunomodulatory molecules, together with non-classical type Ib MHC antigens. In fact, besides HLA-A and HLA-G, HEMSC expressed both HLA-E and HLA-F, two tolerance-promoting HLAs, involved in attenuating NK- and T-cytotoxic responses. In the continued characterization of these cells, we assessed the expression of endoderm-related molecules, suggestive of their possible transdifferentiation towards hepatocytes. In addition to HNF4α and endoderm-related GATA factors (GATA-4,-5,-6), undifferentiated cells expressed also albumin, cytokeratins 18 and 19, and further hepatocyte-enriched transcription factors (as HNF1α, and HNF1β), thus suggesting the possibility to be successfully differentiated towards hepatocytes [2]. The immunological and differentiative properties of human extraembryonic MSC are under intense investigation. Our data suggest that HEMSC bear new markers and have a hypoimmunogenic phenotype which can be a favoring factor to ensure the engraftment of “in vivo” transplanted cells.