Vincenzo Desiderio

Recent studies showed that mesenchymal stem cells derived from adipose tissue can promote tumour progression, raising some concerns regarding their use in regenerative medicine. In this context, we co-cultured either SAOS2 osteosarcoma or MCF7 breast cancer cells with human adipose stem cells (hASCs), in order to evaluate potential effects of cancer cells on hASCs differentiation, in vitro and in vivo. In this study we observed that both SAOS2 and MCF7 cell lines induced an increase in hASCs proliferation, compared to hASCs alone, but, surprisingly, neither changes in the expression of CD90, CD29, CD324 and vimentin, nor variations in the Twist and Slug mRNAs were detectable. Noteworthy, SAOS2 and MCF7 cells induced in hASCs an upregulation of CD34 expression and stemness genes, including OCT3/4, Nanog, Sox2 and leptin, and a decrease in angiogenic factors, including CD31, PDGFα, PDGFRα, PDGFRβ and VEGF. SMAD and pSMAD2/3 increased only in hASCs alone. After 21 days of co-culture, hASCs differentiated both in adipocytes and endothelial cells. Moreover, co-injection of MCF7 cells with hASCs led to the formation of a highly vascularized tumour. Taken together our findings suggest that mesenchymal stem cells, under tumour cell induction, do not differentiate in vitro or facilitate the angiogenesis of the tumour in vivo, thus opening interesting new scenarios in the relationship between cancer and stem cells. These findings may also lead to greater caution, when managing autologous fat grafts in cancer patients.

The aim of this study was to evaluate the behavior of human Dental Pulp Stem Cells (DPSCs), as well as human osteoblasts, when challenged on a Biocoral scaffold, which is a porous natural hydroxyapatite. For this purpose, human DPSCs were seeded onto a three-dimensional (3D) Biocoral scaffold or on flask surface (control). Either normal or rotative (3D) cultures were performed. Scanning electron microscopic analyses, at 8, 24 and 48 h of culture showed that cells did not adhere on the external surface, but moved into the cavities inside the Biocoral structure. After 7, 15 and 30 days of culture, morphological and molecular analyses suggested that the Biocoral scaffold leads DPSCs to hook into the cavities where these cells quickly start to secrete the extra cellular matrix (ECM) and differentiate into osteoblasts. Control human osteoblasts also moved into the internal cavities where they secreted the ECM. Histological sections revealed a diffuse bone formation inside the Biocoral samples seeded with DPSCs or human osteoblasts, where the original scaffold and the new secreted biomaterial were completely integrated and cells were found within the remaining cavities. In addition, RT-PCR analyses showed a significant increase of osteoblast-related gene expression and, above all, of those genes highly expressed in mineralized tissues, including osteocalcin, OPN and BSP. Furthermore, the effects on the interaction between osteogenesis and angiogenesis were observed and substantiated by ELISA assays. Taken together, our results provide clear evidence that DPSCs differentiated into osteoblasts, forming a biocomplex made of Biocoral, ECM and differentiated cells.

Dental pulp stem cells (DPSCs), originating from neural crests, can be found within dental pulp. Up to now, it has been demonstrated that these cells are capable of producing bone tissue, both in vitro and in vivo and differentiate into adipocytes, endotheliocytes, melanocytes, neurons, glial cells, and can be easily cryopreserved and stored. Moreover, recent attention has been focused on tissue engineering and on the properties of these cells. In addition, adult bone tissue with good vascularisation has been obtained in grafts. The latest use in clinical trials for bone repair enforces the notion that DPSCs can be used successfully in patients. Therefore, their isolation, selection, differentiation and banking is of great importance. The isolation and detection techniques used in most laboratories are based on the use of antibodies revealed by flow-cytometers with cell sorter termed FACS (fluorescent activated cell sorter). In this report, we focus our attention on the main procedures used in the selection of DPSCs by flow cytometry, cell culture, freezing/thawing, cell cycle evaluation , histochemistry/immunofluorescence and differentiation of DPSCs. In addition, new methods/protocols to select and isolate stem cells without staining by fluorescent markers for implementation in biomedical/clinical laboratories are discuss. We emphasize that the new methods must address simplicity and short times of preparation and use of samples, complete sterility of cells, the potential disposable, low cost and complete maintenance of the viability and integrity of the cells with real-time response for subsequent applications in the biomedical/clinical/surgical fields.

Bone Tissue Engineering (BTE) and Dental Implantology (DI) require the integration of implanted structures, with well characterized surfaces, in bone. In this work we have challenged acid-etched titanium (AET) and Laser Sintered Titanium (LST) surfaces with either human osteoblasts or stem cells from human dental pulps (DPSCs), to understand their osteointegration and clinical use capability of derived implants. DPSCs and human osteoblasts were challenged with the two titanium surfaces, either in plane cultures or in a roller apparatus within a culture chamber, for hours up to a month. During the cultures cells on the titanium surfaces were examined for histology, protein secretion and gene expression. Results show that a complete osteointegration using human DPSCs has been obtained: these cells were capable to quickly differentiate into osteoblasts and endotheliocytes and, then, able to produce bone tissue along the implant surfaces. Osteoblast differentiation of DPSCs and bone morphogenetic protein production was obtained in a better and quicker way, when challenging stem cells with the LST surfaces. This successful BTE in a comparatively short time gives interesting data suggesting that LST is a promising alternative for clinical use in DI.

Pancreatic islets are commonly isolated for research and transplantation without taking into consideration that they undergo mechanical or chemical stress during this process. In order to counteract both types of injuries, the compound AEOL10150, a novel MnSOD mimic, was added during isolation of islet at concentrations ranging from 18 to 100 mM. Mechanical or chemical stress-related pro-apoptotic signals were then studied. We demonstrate that this MnSOD mimic diminishes the negative effects of mechanical stress by blocking insulin impairment, production of non-specific islet b-cell proteins, transcription of iNOS and FAS, activation of caspase-3 and-9 and, ultimately, apoptosis. Moreover, the effects of the MnSOD mimic on isolated islets were greatly influenced by dosage: the best dose able to fully counteract mechanical stress was found to be 100 mM; doses !150 mM were themselves highly toxic for islet cells. On the other hand, rIL-1b-induced chemical stress is rather complex, and there was no protection in this scenario. Therefore, contrarily to what has been previously reported, MnSOD mimic administration is only capable of counteracting mechanical stress, and not cytokine-induced cytotoxicity, and that this drug acts within a limited concentration range.

Non-hypercalcemic analogs of vitamin D 3 modulate the immune response through antigen-presenting cells (APCs) and activated T-cells. A large population-base case-control showed that vitamin D 3 intake significantly decreases the risk of type 1 diabetes development. The aim of this study was, therefore, to observe the in vivo effects of a vitamin D 3 analog administered to Bio Breeding (BB) rats. 1,25-Dihydroxy-16,23Z-diene-26,27-hexafluoro-19-nor vitamin D 3 (BXL-219, formerly Ro 26-2198) (BioXell, Milan, Italy) was administered in vivo to BB rats from days 42 to 110 of life at 0.2 mg/Kg BW. Control animals received only vehicle (olive oil, 4.8 ml/100 g BW). The animals of these two groups were subjected to insulin treatment as they became diabetic. Insulin (Humulin, 28.6 UI/day) was administered irrespective of diabetes occurrence to another group of rats for comparison. Blood glucose, insulin levels, glycosuria, degree of islet infiltration, and the expression of some antigens were observed. Results showed that the vitamin D 3 analog reduced diabetes incidence, although limitedly, in BB rats while administration of oral insulin increased diabetes incidence. In addition, the vitamin D 3 analog did not stimulate an enhancement in the expression of CD4 and CD25 in BB rats as it does in NOD mice, which may explain the failure of this as well as other antidiabetic treatments in the BB animal model of type 1 diabetes.

Background: Osteosarcoma is the most common primary tumour of bone. Solid tumours are made of heterogeneous cell populations, which display different goals and roles in tumour economy. A rather small cell subset can hold or acquire stem potentials, gaining aggressiveness and increasing expectancy of recurrence. The CD133 antigen is a pentaspan membrane glycoprotein, which has been proposed as a cancer stem cell marker, since it has been previously demonstrated to be capable of identifying a cancer initiating subpopulation in brain, colon, melanoma and other solid tumours. Therefore, our aim was to observe the possible presence of cells expressing the CD133 antigen within solid tumour cell lines of osteosarcoma and, then, understand their biological characteristics and performances.

Mesenchymal stem cell (MSC) therapy holds promise for treating diseases and tissue repair. Regeneration of skeletal muscle tissue that is lost during pathological muscle degeneration or after injuries is sustained by the production of new myofibers. Human Adipose stem cells (ASCs) have been reported to regenerate muscle fibers and reconstitute the pericytic cell pool after myogenic differentiation in vitro. Our aim was to evaluate the differentiation potential of constructs made from a new cross-linked hyaluronic acid (XHA) scaffold on which different sorted subpopulations of ASCs were loaded. Thirty days after engraftment in mice, we found that NG2 þ ASCs underwent a complete myogenic differentiation, fabricating a human skeletal muscle tissue, while NG2 À ASCs merely formed a human adipose tissue. Myogenic differentiation was confirmed by the expression of MyoD, MF20, laminin, and lamin A/C by immunofluorescence and/or RT-PCR. In contrast, adipose differentiation was confirmed by the expression of adiponectin, Glut-4, and PPAR-g. Both tissues formed expressed Class I HLA, confirming their human origin and excluding any contamination by murine cells. In conclusion, our study provides novel evidence that NG2 þ ASCs loaded on XHA scaffolds are able to fabricate a human skeletal muscle tissue in vivo without the need of a myogenic pre-differentiation step in vitro. We emphasize the translational significance of our findings for human skeletal muscle regeneration.

Background: Juvenile polyposis syndrome with gastric involvement may mimic Ménétrier's disease, which is correlated to transforming growth factor (TGF) overproduction and PDX1 upregulation in the gastric fundus. Aim: We report a family with juvenile polyposis syndrome where one member showed typical features of Ménétrier's disease and concomitant Helicobacter pylori infection. Methods: We studied a 31-year-old woman belonging to a family with juvenile polyposis syndrome, who exhibited a particular form of hyperplastic gastropathy diagnosed as Ménétrier's disease with Helicobacter pylori infection. Results: TGF˛ overexpression and undetectable PDX1 expression were demonstrated in the fundic gastric biopsy specimens. In all affected members of the family we identified a 4-bp deletion in exon 9 of SMAD4 gene, a mutation usually associated with a more virulent form of juvenile polyposis syndrome with a higher incidence of gastric and colonic polyposis. Conclusion: To explain the association of juvenile polyposis syndrome with Ménétrier's disease we hypothesized a new mechanism that involves TGF-SMAD4 pathway inactivation and TGF overex-pression related to Helicobacter pylori infection.

New delivery systems including liposomes have been developed to circumvent drug resistance. To enhance the antitumor efficacy of liposomes encapsulating anti-cancer agents, we used liposomes externally conjugated to the 20 residue peptide gH625. Physicochemical characterization of the liposome system showed a size of 140 nm with uniform distribution and high doxorubicin encapsulation efficiency. We evaluated the effects of increasing concentrations of liposomes encapsulating Doxo (LipoDoxo), liposomes encapsulating Doxo conjugated to gH625 (LipoDoxo-gH625), empty liposomes (Lipo) or free Doxo on growth inhibition of either wild type (A549) or doxorubicin-resistant (A549 Dx) human lung adenocarcinoma. After 72 h, we found that the growth inhibition induced by LipoDoxo-gH625 was higher than that caused by LipoDoxo with an IC 50 of 1 and 0.3 μM in A549 and A549 Dx cells, respectively. The data on cell growth inhibition were paralleled by an higher oxidative stress and an increased uptake of Doxo induced by LipoDoxo-gH625 compared to LipoDoxo, above all in A549 Dx cells. Cytometric analysis showed that the antiproliferative effects of each drug treatment were mainly due to the induction of apoptosis. In conclusion,liposomes armed with gH625 are able to overcome doxorubicin resistance in lung adenocarcinoma cell lines.

j o u r n a l o f d e n t i s t r y 4 2 (2 0 1 4) 7 6 1 – 7 6 8 a b s t r a c t Objectives: Stem cells have the ability to rescue and/or repair injured tissue. In humans, it is possible to isolate different types of stem cells from the body. Among these, dental pulp stem cells (DPSCs) are relatively easily obtainable and exhibit high plasticity and multipo-tential capabilities. In particular they represent a gold standard for neural-crest-derived bone reconstruction in humans and can be used for the repair of body defects in low-risk autologous therapeutic strategies. Sources: An electronic search was conducted on PubMed databases and supplemented with a manual study of relevant references. Results: All research described in this review highlight that DPSCs are mesenchymal stem cells that could be used in clinical applications. Unfortunately, very few clinical trials have been reported. Major obstacles imposed on researchers are hindering the translation of potentially effective therapies to the clinic. Both researchers and regulatory institutions need to develop a new approach to this problem, drawing up a new policy for good manufacturing practice (GMP) procedures. We strongly suggest that only general rules be standardized rather than everything. Importantly, this would not have an effect on the safety of patients, but may very well affect the results, which cannot be identical for all patients, due to physiological diversity in the biology of each patient. Alternatively, it would be important to study the role of specific molecules that recruit endogenous stem cells for tissue regeneration. In this way, the clinical use of stem cells could be successfully developed. Conclusions: DPSCs are mesenchymal stem cells that differentiate into different tissues, maintain their characteristics after cryopreservation, differentiate into bone-like tissues when loaded on scaffolds in animal models, and regenerate bone in human grafts. In summary, all data reported up to now should encourage the development of clinical procedures using DPSCs.

Adult mesenchymal stem cells, such as dental pulp stem cells, are of great interest for cell-based tissue engineering strategies because they can differentiate into a variety of tissue-specific cells, above all, into osteoblasts. In recent years, epigenetic studies on stem cells have indicated that specific histone alterations and modifying enzymes play essential roles in cell differentiation. However, although several studies have reported that valproic acid (VPA)—a selective inhibitor of histone deacetylases (HDAC)—enhances osteoblast differentiation, data on osteocalcin expression—a late-stage marker of differentiation—are limited. We therefore decided to study the effect of VPA on dental pulp stem cell differentiation. A low concentration of VPA did not reduce cell viability, proliferation, or cell cycle profile. However, it was sufficient to significantly enhance matrix mineralization by increasing osteopontin and bone sialoprotein expression. In contrast, osteocalcin levels were decreased, an effect induced at the transcrip-tional level, and were strongly correlated with inhibition of HDAC2. In fact, HDAC2 silencing with shRNA produced a similar effect to that of VPA treatment on the expression of osteoblast-related markers. We conclude that VPA does not induce terminal differentiation of osteoblasts, but stimulates the generation of less mature cells. Moreover, specific suppression of an individual HDAC by RNA interference could enhance only a single aspect of osteoblast differentiation, and thus produce selective effects. STEM CELLS 2014;32:279–289

Objective—To evaluate in vitro the potential links between sialyl Lewis X (sLeX) and cancer stem cells (CSC) in head and neck squamous cell carcinoma (HNSCC). HNSCC is an aggressive malignancy with high mortality mainly due to metastasis. CSC have emerged as important players in HNSCC metastasis. sLeX is a tetrasaccharide carbohydrate known to play a key-role in metastatic dissemination by promoting binding of the tumor cells to the endothelium. Study Design—Experimental, in vitro. Setting—Laboratory of Head and Neck Cancer Metastasis, University of Michigan. Subjects and Methods—A panel of stage-and anatomic-site specific primary and metastatic HNSCC cell lines was assessed by flow cytometry to quantify sLeX relative expression levels. Serum-free conditioned media from the same HNSCC lines was collected over a time-course of 72 hours and assessed by Western-blot for secreted sLeX expression. Representative HNSCC cell lines were cultured as floating orospheres (condition that enhance CSC growth) or under normal adherent conditions and characterized by flow cytometry for CSC markers (CD44, aldehyde dehydrogenase [ALDH]) comparatively with sLeX expression. Results—sLeX is predominantly expressed in carcinomas originating from the oral cavity. Secreted sLeX is also found to be high in oral carcinomas and increased over the analyzed time

Mesenchymal stem cells deriving from dental pulp differentiate into osteoblasts capable of producing bone. In previous studies, we extensively demonstrated that, when seeded on collagen I scaffolds , these cells can be conveniently used for the repair of human mandible defects. Here, we assess the stability and quality of the regenerated bone and vessel network 3 years after the grafting intervention, with conventional procedures and in-line holotomography, an advanced phase-imaging method using synchrotron radiation that offers improved sensitivity toward low-absorbing structures. We found that the regenerated tissue from the graft sites was composed of a fully compact bone with a higher matrix density than control human alveolar spongy bone from the same patient. Thus, the regenerated bone, being entirely compact, is completely different from normal alveolar bone. Although the bone regenerated at the graft sites is not of the proper type found in the mandible, it does seem to have a positive clinical impact. In fact, it creates steadier mandibles, may well increase implant stability, and, additionally, may improve resistance to mechanical, physical, chemical, and pharmacological agents. STEM CELLS TRANSLATIONAL MEDICINE 2013;2: 316 –324

Oral squamous cell carcinoma (OSCC) is an aggressive malignancy with high mortality rates. Major challenges for OSCC management include development of resistance to therapy and early formation of distant metastases. Cancer stem cells (CSCs) have emerged as important players in both pathologic mechanisms. Increased fucosylation activity and increased expression of fucosylated polysaccharides, such as Sialyl Lewis X (SLe x), are associated with invasion and metastasis. However, the role of fucosylation in CSCs has not been elucidated yet. We used the spheroid culture technique to obtain a CSC-enriched population and compared orospheres with adherent cells. We found that orospheres expressed markers of CSCs and metastasis at higher levels, were more invasive and tumorigenic, and were more resistant to cisplatin/radiation than adherent counterparts. We found fucosyltransferases FUT3 and FUT6 highly up-regulated, increased SLe x expression and increased adhesion by shear flow assays in orospheres. Inhibition of fucosylation negatively affected orospheres formation and invasion of oral CSCs. These results confirm that orospheres are enriched in CSCs and that fucosylation is of paramount importance for CSC invasion. In addition, SLe x may play a key role in CSC metastasis. Thus, inhibition of fucosylation may be used to block CSCs and metastatic spread.

Bone defects are one of the most serious pathologies that need tissue regeneration therapies. Studies on mesenchymal stem cells are changing the way we treat bone diseases. MSCs have been used for the treatment of osteogenesis imperfecta, hypophosphatasia, osteonecrosis of the femoral head, osteoporosis, rheumatoid arthritis and osteoarthritis. In this context, it is becoming ever more clear that the future of therapies will be based on the use of stem cells. In this concise review, we highlight the importance of the use of MSCs in bone diseases, focusing on the role of histone deacetylases and Wnt pathways involved in osteogenesis. A better understanding of MSC biology and osteogenesis is needed in order to develop new and targeted therapeutic strategies for the treatment of bone diseases/disorders.

Craniofacial area represent a unique district of human body characterized by a very high complexity of tissues, innervation and vascularization, and being deputed to many fundamental function such as eating, speech, expression of emotions, delivery of sensations such as taste, sight, and earing. For this reasons, tissue loss in this area following trauma or for example oncologic resection, have a tremendous impact on patients' quality of life. In the last 20 years regenerative medicine has emerged as one of the most promising approach to solve problem related to trauma, tissue loss, organ failure etc. One of the most powerful tools to be used for tissue regeneration is represented by stem cells, which have been successfully implanted in different tissue/organs with exciting results. Nevertheless, both autologous and allogeneic stem cell transplantation raise many practical and ethical concerns that make this approach very difficult to apply in clinical practice. For this reason different cell free approaches have been developed aiming to the mobilization, recruitment, and activation of endogenous stem cells into the injury site avoiding exogenous cells implant but instead stimulating patients' own stem cells to repair the lesion. To this aim many strategies have been used including functionalized bioscaffold, controlled release of stem cell chemoattractants, growth factors, BMPs, Platelet–Rich-Plasma, and other new strategies such as ultrasound wave and laser are just being proposed. Here we review all the current and new strategies used for activation and mobilization of endogenous stem cells in the regeneration of craniofacial tissue.

New delivery systems including liposomes have been developed to circumvent drug resistance. To enhance the antitumor efficacy of liposomes encapsulating anti-cancer agents, we used liposomes externally conjugated to the 20 residue peptide gH625. Physicochemical characterization of the liposome system showed a size of 140 nm with uniform distribution and high doxorubicin encapsulation efficiency. We evaluated the effects of increasing concentrations of liposomes encapsulating Doxo (LipoDoxo), liposomes encapsulating Doxo conjugated to gH625 (LipoDoxo-gH625), empty liposomes (Lipo) or free Doxo on growth inhibition of either wild type (A549) or doxorubicin-resistant (A549 Dx) human lung adenocarcinoma. After 72 h, we found that the growth inhibition induced by LipoDoxo-gH625 was higher than that caused by LipoDoxo with an IC50 of 1 and 0.3 μM in A549 and A549 Dx cells, respectively. The data on cell growth inhibition were paralleled by an higher oxidative stress and an increased uptak...

The overexpression of ATP binding cassette (ABC) transporters makes tumor cells simultaneously resistant to several cytotoxic drugs. Impairing the energy metabolism of multidrug resistant (MDR) cells is a promising chemosensitizing strategy, but many metabolic modifiers are too toxic in vivo. We previously observed that the aminobisphosphonate zoledronic acid inhibits the activity of hypoxia inducible factor-1a (HIF-1a), a master regulator of cancer cell metabolism. Free zoledronic acid, however, reaches low intratumor concentration. We synthesized nanoparticle formulations of the aminobisphosphonate that allow a higher intratumor delivery of the drug. We investigated whether they are effective metabolic modifiers and chemosensitizing agents against human MDR cancer cells in vitro and in vivo.At not toxic dosage, nanoparticles carrying zoledronic acid chemosensitized MDR cells to a broad spectrum of cytotoxic drugs, independently of the type of ABC transporters expressed. The nanopa...

Salivary gland (SG) cancer constitute 1-6% of head and neck malignancies and remains one of the less characterized at the molecular level. Currently there are limited therapeutic options for this group of deadly cancer. Increasing our understanding on the molecular mechanisms governing SG tumorigenesis will allow better treatment options in the future. The circadian clock is a mechanism that controls most cellular and metabolic processes. Increasing evidence indicates that disruption of circadian rhythms deregulates cell proliferation and significantly increases cancer risk. Among the clock genes, Per2 has drawn particular attention since it is a tumor suppressor gene. In addition, Per2 is strongly expressed in SG and Per2 knock-out (Per2KO) mice have a phenotype altered SG development. Objective: Our aim is to define Per2 function in SG tumorigenesis. Methods: Per2KO mice were characterized by immunohistochemistry, histological analysis, quantitative real-time RT-PCR, RNA arrays an...

Objective: The major challenge in the management of patients with oral squamous cell carcinomas (OSCC) is the development of resistance to therapy leading to disseminated disease. Since cancer stem cells (CSC) have emerged as important players in OSCC metastasis, our objectives were to explore the implications of CSC in OSCC tumor progression, invasion and response to conventional therapies. Methods: A panel of well-characterized cell lines originated from the most common sites in the head and neck area was used. Cells were cultured as floating spheres (condition that enhances CSC growth) or under normal adherent conditions and analyzed for CD44, ALDH and markers for OSCC metastasis by flow cytometry and PCR microarrays. We also investigated sLeX expression, known to play a key-role in colorectal cancer metastasis by promoting tumor cells binding to endothelial E-selectin. We analyzed the tumorigenic potential of OSCC cells by invasion assays and in vivo OSCC experimental models com...

In this study we used a biocomplex constructed from dental pulp stem/progenitor cells (DPCs) and a collagen sponge scaffold for oro-maxillo-facial (OMF) bone tissue repair in patients requiring extraction of their third molars. The experiments were carried out according to our Internal Ethical Committee Guidelines and written informed consent was obtained from the patients. The patients presented with bilateral bone reabsorption of the alveolar ridge distal to the second molar secondary to impaction of the third molar on the cortical alveolar lamina, producing a defect without walls, of at least 1.5 cm in height. This clinical condition does not permit spontaneous bone repair after extraction of the third molar, and eventually leads to loss also of the adjacent second molar. Maxillary third molars were extracted first for DPC isolation and expansion. The cells were then seeded onto a collagen sponge scaffold and the obtained biocomplex was used to fill in the injury site left by ext...

During human embryonic development, odontogenic tissues, deriving from the neural crest, remain undifferentiated until the adult age. This study was aimed at characterising the cells of the follicle enveloping the dental germ, due to its direct origin from neural crests. Sixty dental follicles were collected from patients aged 18 to 45 years. This research has clarified that dental follicles, if extracted in a very early stage, when dental roots did not start to be formed, contain a lineage of cells, characterised by a high degree of plasticity in comparison with other adult stem cell populations. In particular, we found that these cells share the following features with ES: (i) high levels of embryonic stem cell markers (CD90, TRA1-60, TRA1-81, OCT-4, CD133, and SSEA-4); (ii) mRNA transcripts for Nanog and Rex-1; (iii) broader potency, being able to differentiate in cell types of all three germ layer, including smooth and skeletal muscle, osteoblasts, neurons, glial cells, and adip...

Mesenchymal stem cells deriving from dental pulp differentiate into osteoblasts capable of producing bone. In previous studies, we extensively demonstrated that, when seeded on collagen I scaffolds, these cells can be conveniently used for the repair of human mandible defects. Here, we assess the stability and quality of the regenerated bone and vessel network 3 years after the grafting intervention, with conventional procedures and in-line holotomography, an advanced phase-imaging method using synchrotron radiation that offers improved sensitivity toward low-absorbing structures. We found that the regenerated tissue from the graft sites was composed of a fully compact bone with a higher matrix density than control human alveolar spongy bone from the same patient. Thus, the regenerated bone, being entirely compact, is completely different from normal alveolar bone. Although the bone regenerated at the graft sites is not of the proper type found in the mandible, it does seem to have ...

Osteosarcoma is the most common primary tumour of bone. Solid tumours are made of heterogeneous cell populations, which display different goals and roles in tumour economy. A rather small cell subset can hold or acquire stem potentials, gaining aggressiveness and increasing expectancy of recurrence. The CD133 antigen is a pentaspan membrane glycoprotein, which has been proposed as a cancer stem cell marker, since it has been previously demonstrated to be capable of identifying a cancer initiating subpopulation in brain, colon, melanoma and other solid tumours. Therefore, our aim was to observe the possible presence of cells expressing the CD133 antigen within solid tumour cell lines of osteosarcoma and, then, understand their biological characteristics and performances. In this study, using SAOS2, MG63 and U2OS, three human sarcoma cell lines isolated from young Caucasian subjects, we were able to identify and characterize, among them, CD133+ cells showing the following features: hi...

Adult mesenchymal stem cells, such as dental pulp stem cells, are of great interest for cell-based tissue engineering strategies because they can differentiate into a variety of tissue-specific cells, above all, into osteoblasts. In recent years, epigenetic studies on stem cells have indicated that specific histone alterations and modifying enzymes play essential roles in cell differentiation. However, although several studies have reported that valproic acid (VPA)-a selective inhibitor of histone deacetylases (HDAC)-enhances osteoblast differentiation, data on osteocalcin expression-a late-stage marker of differentiation-are limited. We therefore decided to study the effect of VPA on dental pulp stem cell differentiation. A low concentration of VPA did not reduce cell viability, proliferation, or cell cycle profile. However, it was sufficient to significantly enhance matrix mineralization by increasing osteopontin and bone sialoprotein expression. In contrast, osteocalcin levels were decreased, an effect induced at the transcriptional level, and were strongly correlated with inhibition of HDAC2. In fact, HDAC2 silencing with shRNA produced a similar effect to that of VPA treatment on the expression of osteoblast-related markers. We conclude that VPA does not induce terminal differentiation of osteoblasts, but stimulates the generation of less mature cells. Moreover, specific suppression of an individual HDAC by RNA interference could enhance only a single aspect of osteoblast differentiation, and thus produce selective effects.