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We propose a new organ-conditioning strategy based on mesenchymal stromal cell (MSCs)/extracellular vesicle (EVs) delivery during hypothermic perfusion. MSCs/EVs marker CD73 is present on renal proximal tubular cells, and it protects against renal ischemia-reperfusion injury by converting adenosine monophosphate into adenosine (ADO). In this study, after checking if CD73-silenced EVs (EVsi) would impact in vitro tubular-cell proliferation, we perfused kidneys of a rat model of donation after circulatory death, with Belzer solution (BS) alone, BS supplemented with MSCs, EVs, or EVsi. The ADO and ATP levels were measured in the effluents and tissues. Global renal ischemic damage score (GRS), and tubular cell proliferation index (IPT) were evaluated in the tissue. EVsi did not induce cell proliferation in vitro. Ex vivo kidneys perfused with BS or BS + EVsi showed the worst GRS and higher effluent ADO levels than the MSC- and EV-perfused kidneys. In the EV-perfused kidneys, the tissue and effluent ATP levels and IPT were the highest, but not if CD73 was silenced. Tissue ATP content was positively correlated with tissue ADO content and negatively correlated with effluent ADO level in all groups. In conclusion, kidney conditioning with EVs protects against ischemic damage by activating the CD73/ADO system.

Muscular regeneration is a complex biological process that occurs during acute injury and chronic degeneration, implicating several cell types. One of the earliest events of muscle regeneration is the inflammatory response, followed by the activation and differentiation of muscle progenitor cells. However, the process of novel neuromuscular junction formation during muscle regeneration is still largely unexplored. Here, we identify by single-cell RNA sequencing and isolate a subset of vessel-associated cells able to improve myogenic differentiation. We termed them 'guide' cells because of their remarkable ability to improve myogenesis without fusing with the newly formed fibers. In vitro, these cells showed a marked mobility and ability to contact the forming myotubes. We found that these cells are characterized by CD44 and CD34 surface markers and the expression of Ng2 and Ncam2. In addition, in a murine model of acute muscle injury and regeneration, injection of guide cells correlated with increased numbers of newly formed neuromuscular junctions. Thus, we propose that guide cells modulate de novo generation of neuromuscular junctions in regenerating myofibers. Further studies are necessary to investigate the origin of those cells and the extent to which they are required for terminal specification of regenerating myofibers. ispartof: INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES vol:22 issue:4 ispartof: location:Switzerland status: published

Lower limb explosive strength has been widely used to evaluate physical fitness and general health in children. A plethora of studies have scoped the practicality of the standing broad jump (SBJ), though without accounting for body dimensions, which are tremendously affected by growth. This study aimed at modeling SBJ-specific allometric equations, underlying an objectively predictive approach while controlling for maturity offset (MO). A total of 7317 children (8&ndash, 11 years) were tested for their SBJs, demographics and anthropometrics data were also collected. The multiplicative model with allometric body size components, MO, and categorial differences were implemented with SBJ performance. The log-multiplicative model suggested that the optimal body shape associated with SBJs is ectomorphic (H = &minus, 0.435, M = 1.152). Likewise, age, sex, and age&ndash, sex interactions were revealed to be significant (p &lt, 0.001). Our results confirmed the efficacy of the allometric approach to identify the most appropriate body size and shape in children. Males, as they mature, did not significantly augment their performances, whereas females did, outperforming their peers. The model successfully fit the equation for SBJ performance, adjusted for age, sex, and MO. Predictive equations modeled on developmental factors are needed to interpret appropriately the performances that are used to evaluate physical fitness.

Human bone marrow-derived mesenchymal stem cells (hBM-MSCs) are considered a great promise in the repair and regeneration of bone. Considerable efforts have been oriented towards uncovering the best strategy to promote stem cells osteogenic differentiation. In previous studies, hBM-MSCs exposed to physical stimuli such as pulsed electromagnetic fields (PEMFs) or directly seeded on nanostructured titanium surfaces ($TiO_{2}$) were shown to improve their differentiation to osteoblasts in osteogenic condition. In the present study, the effect of a daily PEMF-exposure on osteogenic differentiation of hBM-MSCs seeded onto nanostructured $TiO_{2}$ (with clusters under 100 nm of dimension) was investigated. $TiO_{2}$-seeded cells were exposed to PEMF (magnetic field intensity: 2 mT; intensity of induced electric field: 5 mV; frequency: 75 Hz) and examined in terms of cell physiology modifications and osteogenic differentiation. Results showed that PEMF exposure affected $TiO_{2}$-seeded cells osteogenesis by interfering with selective calcium-related osteogenic pathways, and greatly enhanced hBM-MSCs osteogenic features such as the expression of early/late osteogenic genes and protein production (e.g., ALP, COL-I, osteocalcin and osteopontin) and ALP activity. Finally, PEMF-treated cells resulted to secrete into conditioned media higher amounts of BMP-2, DCN and COL-I than untreated cell cultures. These findings confirm once more the osteoinductive potential of PEMF, suggesting that its combination with $TiO_{2}$ nanostructured surface might be a great option in bone tissue engineering applications.

Defective cell migration causes delayed wound healing (WH) and chronic skin lesions. Autologous micrograft (AMG) therapies have recently emerged as a new effective and affordable treatment able to improve wound healing capacity. However, the precise molecular mechanism through which AMG exhibits its beneficial effects remains unrevealed. Herein we show that AMG improves skin re-epithelialization by accelerating the migration of fibroblasts and keratinocytes. More specifically, AMG-treated wounds showed improvement of indispensable events associated with successful wound healing such as granulation tissue formation, organized collagen content, and newly formed blood vessels. We demonstrate that AMG is enriched with a pool of WH-associated growth factors that may provide the starting signal for a faster endogenous wound healing response. This work links the increased cell migration rate to the activation of the extracellular signal-regulated kinase (ERK) signaling pathway, which is followed by an increase in matrix metalloproteinase expression and their extracellular enzymatic activity. Overall we reveal the AMG-mediated wound healing transcriptional signature and shed light on the AMG molecular mechanism supporting its potential to trigger a highly improved wound healing process. In this way, we present a framework for future improvements in AMG therapy for skin tissue regeneration applications. ispartof: Cell Death And Differentiation vol:27 issue:5 ispartof: location:England status: Published online

In the last 15 years, it emerged that the practice of regular physical activity reduces the risks of many diseases (cardiovascular diseases, diabetes, etc.) and it is fundamental in weight control and energy consuming to contrast obesity. Different groups proposed many molecular mechanisms as responsible for the positive effects of physical activity in healthy life. However, many points remain to be clarified. In this mini-review we reported the latest observations on the effects of physical exercise on healthy skeletal and cardiac muscle focusing on muscle stem cells. The last ones represent the fundamental elements for muscle regeneration post injury, but also for healthy muscle homeostasis. Interestingly, in both muscle tissues the morphological consequence of physical activity is a physiological hypertrophy that depends on different phenomena both in differentiated cells and stem cells. The signaling pathways for physical exercise effects present common elements in skeletal and cardiac muscle, like activation of specific transcription factors, proliferative pathways, and cytokines. More recently, post translational (miRNAs) or epigenetic (DNA methylation) modifications have been demonstrated. However, several points remain unresolved thus requiring new research on the effect of exercise on muscle stem cells.

Platelet rich plasma (PRP) and Micrografts containing human follicle mesenchymal stem cells (HF-MSCs) were tried as a potential treatment for androgenetic alopecia (AGA). However, little to no work has yet to be seen wherein the bio-molecular pathway of HF-MSCs or PRP treatments were analyzed. The aims of this work are to report the clinical effectiveness of HF-MSCs and platelet-rich plasma evaluating and reviewing the most updated information related to the bio-molecular pathway. Twenty-one patients were treated with HF-MSCs injections and 57 patients were treated with A-PRP. The Wnt pathway and Platelet derived-growth factors effects were analyzed. 23 weeks after the last treatment with mean hair thickness increments (29 &plusmn, 5.0%) over baseline values for the targeted area. 12 weeks after the last injection with A-PRP mean hair count and hair density (31 &plusmn, 2%) increases significantly over baseline values. The increment of Wnt signaling in Dermal Papilla Cells evidently is one of the principal factors that enhances hair growth. Signaling from mesenchymal stem cells and platelet derived growth factors positively influences hair growth through cellular proliferation to prolong the anagen phase (FGF-7), inducing cell growth (ERK activation), stimulating hair follicle development (&beta, catenin), and suppressing apoptotic cues (Bcl-2 release and Akt activation).

We report the study of novel biodegradable electrospun scaffolds from poly(butylene 1,4-cyclohexandicarboxylate-co-triethylene cyclohexanedicarboxylate) (P(BCE-co-TECE)) as support for in vitro and in vivo muscle tissue regeneration. We demonstrate that chemical composition, i.e., the amount of TECE co-units (constituted of polyethylene glycol-like moieties), and fibre morphology, i.e., aligned microfibrous or sub-microfibrous scaffolds, are crucial in determining the material biocompatibility. Indeed, the presence of ether linkages influences surface wettability, mechanical properties, hydrolytic degradation rate, and density of cell anchoring points of the studied materials. On the other hand, electrospun scaffolds improve cell adhesion, proliferation, and differentiation by favouring cell alignment along fibre direction (fibre morphology), also allowing for better cell infiltration and oxygen and nutrient diffusion (fibre size). Overall, C2C12 myogenic cells highly differentiated into mature myotubes when cultured on microfibres realised with the copolymer richest in TECE co-units (micro-P73 mat). Lastly, when transplanted in the tibialis anterior muscles of healthy, injured, or dystrophic mice, micro-P73 mat appeared highly vascularised, colonised by murine cells and perfectly integrated with host muscles, thus confirming the suitability of P(BCE-co-TECE) scaffolds as substrates for skeletal muscle tissue engineering. This work has been supported by FWO (#G060612N, #G0A8813N, and #G088715N), CARIPLO Foundation #2015_0634, Opening the Future Campaign #EJJ-OPTFUT-02010, Excellentiefinanciering KULStem Cells #ETH-C1900-PF grant, Rondoufondsvoor Duchenne Onderzoek and the Belgian Agency for Science Policy IUAPVII-07 DevRepair (Belspo) network to M.S. EB was supported by FWO Post-Doctoral Fellowship (12D2813N) and an FWO grant (1525315N). We would like to acknowledge the support from the FP7 COST Action MP1206 “Electrospun Nanofibres for Bioinspired Composite Materials and Innovative Industrial Applications”. We also thank the financial support from “International Mobility Project” AA 2013-2014 of the University of Pavia and the POR-FESR grant, Regione Emilia Romagna (University of Bologna). We are grateful to P. Vaghi (Centro Grandi Strumenti, University of Pavia, Pavia, Italy) for technical assistance in the confocal laser scanning microscope. We thank C. Reviglio for her assistance in material preparation. This research was also supported by a grant of the Italian Ministry of Education, University and Research (MIUR) to the Department of Molecular Medicine of the University of Pavia under the initiative “Dipartimenti di Eccellenza (2018–2022)”. This publication is distributed under the terms of open access policies implemented by the Italian Ministry of Education, University, and Research (MIUR).

The dystrophin-glycoprotein complex (DGC) is composed of several transmembrane and peripheral components localized in the sarcolemma of skeletal muscle. Mutations in genes that encode DGC components lead to the loss of either expression and/or function of the DGC in muscle. As DGC complex interacts with F-actin it is reasonable that the multidomain F-actin binding protein MICAL2 that transduces semaphorin/plexin external signaling into cytoskeletal modifications, might interact either directly or indirectly with the DGC complex. MICAL2 is indeed expressed in skeletal and cardiac muscles and drosophila Mical mutants reveal that the architecture of contractile muscle filaments is negatively affected. We focus here on the role of MICALs in myogenic differentiation. The rationale to investigate MICAL2 in muscle differentiation is also highlighted in a paper regarding a complex muscle genome-wide expression profiling during the disease evolution in mdx mice, a mouse model of Duchenne muscular dystrophy (1). In this study the authors found MICAL2 among a set of totally ten functionally linked genes involved in the decline of muscle necrosis in mdx mice. For this purpose MICAL2 gain and loss of function studies have been performed in myogenic cell line and compared to in vivo analysis of MICAL2 expressions in acute and chronic muscle degeneration. Recently we showed that that differential myogenic propensity influences the commitment of isogenic induce pluripotent stem cells and a specifically isolated pool of mesodermal iPSC-derived progenitors (MiPs) toward the striated muscle lineages (2). Analysis of MICAL2 expression in MiPs is currently under investigation. Taken together modulation of MICAL2 has an impact on skeletal muscle commitment and could be considered a potential therapeutic target for Duchenne patients. This work was supported with the contribution of “Opening The Future” Campaign [EJJ-OPTFUT-02010] CARIPLO 2015_0634, FWO (#G088715N, #G060612N, #G0A8813N), and IUAP-VII/07 (EJJ-C4851-17/07-P) grants., Italian Journal of Anatomy and Embryology, Vol. 121, No. 1 (Supplement) 2016

Cartilage defects represent a serious problem due to the poor regenerative properties of this tissue. Regarding the nose, nasal valve collapse is associated with nasal blockage and persistent airway obstruction associated with a significant drop in the quality of life for patients. In addition to surgical techniques, several cell-based tissue-engineering strategies are studied to improve cartilage support in the nasal wall, that is, to ameliorate wall insufficiency. Nevertheless, there are no congruent data available on the benefit for patients during the follow-up time. In this manuscript, we propose an innovative approach in the treatment of cartilage defects in the nose (nasal valve collapse) based on autologous micro-grafts obtained by mechanical disaggregation of a small portion of cartilage tissue (Rigenera® protocol). In particular, we first analyzed in vitro murine and human cartilage micro-grafts; secondly, we analyzed the clinical results of a patient with pinched nose deformity treated with autologous micro-grafts of chondrocytes obtained by Rigenera® protocol. The use of autologous micro-graft produced promising results in surgery treatment of cartilage injuries and could be safely and easily administrated to patients with cartilage tissue defects.

Background: The etiology of non-healing ulcers depends on both systemic and local factors. The introduction of advanced dressing, negative wound therapy and compression therapy have undoubtedly improved clinical outcomes. The principal aim of study was to demonstrate the efficacy of dermal micrografts in the treatment of ulcers with different etiologies. The second aim was to investigate in vitro the action of micrografts in the regenerative process. Methods: The dermal micro-grafts were obtained from mechanical disaggregation of small pieces of skin tissue through a medical device called Rigeneracons. Results: We observed in vivo the ability of dermal autologous micrografts to improve the healing of venous, diabetic, pressure and post-traumatic ulcers after few week of treatment accomplished in general with a better quality of life for the patients. In vitro results showed that these micrografts express mesenchymal stem cells (MSCS) marker such as CD34, CD73, CD90 and CD105, and are able to form a viable and proliferative biocomplex with collagen sponge. Finally, the site of ulcers displayed a different expression of epidermal growth factors, insulin-like growth factors, platelet-derived growth factors and their receptors and tumor necrosis factor-β with respect to healthy skin samples. Conclusion: We reported a good outcome for the treatment of chronic ulcers using dermal autologous micrografts. Finally, we suggest that the positivity to MSCs markers and the ability to interact with a scaffold can play a key role in their regenerative properties. Background The etiology of non-healing ulcers depends on both systemic and local factors. The introduction of advanced dressing, negative wound therapy and compression therapy have undoubtedly improved clinical outcomes. The principal aim of study was to demonstrate the efficacy of dermal micrografts in the treatment of ulcers with different etiologies. The second aim was to investigate in vitro the action of micrografts in the regenerative process.Methods The dermal micro-grafts were obtained from mechanical disaggregation of small pieces of skin tissue through a medical device called Rigeneracons.Results We observed in vivo the ability of dermal autologous micrografts to improve the healing of venous, diabetic, pressure and post-traumatic ulcers after few week of treatment accomplished in general with a better quality of life for the patients. In vitro results showed that these micrografts express mesenchymal stem cells (MSCS) marker such as CD34, CD73, CD90 and CD105, and are able to form a viable and proliferative biocomplex with collagen sponge. Finally, the site of ulcers displayed a different expression of epidermal growth factors, insulin-like growth factors, platelet-derived growth factors and their receptors and tumor necrosis factor-beta with respect to healthy skin samples.Conclusion We reported a good outcome for the treatment of chronic ulcers using dermal autologous micrografts. Finally, we suggest that the positivity to MSCs markers and the ability to interact with a scaffold can play a key role in their regenerative properties.

The use of gold nanoparticles as drug delivery system represents a promising issue for diseases without effective pharmacological treatment due to insufficient local drug accumulation and excessive systemic toxicity. Bronchiolitis obliterans syndrome (BOS) represents about 70% of cases of chronic lung allograft dysfunction, the main challenge to long term lung transplantation. It is believed that due to repeated insults to epithelial bronchiolar cells local inflammatory response creates a milieu that favours epithelial mesenchymal transition and activation of local mesenchymal cells leading to airway fibro-obliteration. In a previous work, we engineered gold nanoparticles loaded with the mTOR inhibitor everolimus, specifically decorated with an antibody against CD44, a surface receptor expressed by primary mesenchymal cells isolated from bronchoalveolar lavage of BOS patients. We proved in vitro that these gold nanoparticles (GNP-HCe) were able to specifically inhibit primary mesenchymal cells without affecting bronchial epithelial cell. In the present work, we investigated the effect of the these bioengineered nanoconstructs on inflammatory cells, given that a stimulating effect on macrophages, neutrophils or lymphocytes is strongly unwanted in graft airways since it would foster fibro-genesis. In addition, we administered GNP-HCe by inhalatory route to normal mice for a preliminary assessment of their pulmonary and peripheral (liver, spleen and kidney) uptake. By these experiments, an evaluation of tissue toxicity was also performed. Present study proves that our bioengineered nanotools do not rise an inflammatory response and, under the tested inhalatory conditions that were used, are nontoxic.

Background: Myogenic progenitor cells (activated satellite cells) are able to express both HGF and its receptor cMet. After muscle injury, HGF-Met stimulation promotes activation and primary division of satellite cells. MAGIC-F1 (Met-Activating Genetically Improved Chimeric Factor-1) is an engineered protein that contains two human Met-binding domains that promotes muscle hypertrophy. MAGIC-F1 protects myogenic precursors against apoptosis and increases their fusion ability enhancing muscle differentiation. Hemizygous and homozygous Magic-F1 transgenic mice displayed constitutive muscle hypertrophy. Methods: Here we describe microarray analysis on Magic-F1 myogenic progenitor cells showing an altered gene signatures on muscular hypertrophy and angiogenesis compared to wild-type cells. In addition, we performed a functional analysis on Magic-F1+/+ transgenic mice versus controls using treadmill test. Results: We demonstrated that Magic-F1+/+ mice display an increase in muscle mass and cross-sectional area leading to an improvement in running performance. Moreover, the presence of MAGIC-F1 affected positively the vascular network, increasing the vessel number in fast twitch fibers. Finally, the gene expression profile analysis of Magic-F1+/+ satellite cells evidenced transcriptomic changes in genes involved in the control of muscle growth, development and vascularisation. Conclusion: We showed that MAGIC-F1-induced muscle hypertrophy affects positively vascular network, increasing vessel number in fast twitch fibers. This was due to unique features of mammalian skeletal muscle and its remarkable ability to adapt promptly to different physiological demands by modulating the gene expression profile in myogenic progenitors.

Human mesenchymal stem cells (MSCs) are a promising candidate cell type for regenerative medicine and tissue engineering applications. Exposure of MSCs to physical stimuli favors early and rapid activation of the tissue repair process. In this study we investigated the in vitro effects of pulsed electromagnetic field (PEMF) treatment on the proliferation and osteogenic differentiation of bone marrow MSCs (BM-MSCs) and adipose-tissue MSCs (ASCs), to assess if both types of MSCs could be indifferently used in combination with PEMF exposure for bone tissue healing. We compared the cell viability, cell matrix distribution, and calcified matrix production in unstimulated and PEMF-stimulated (magnetic field: 2 mT, amplitude: 5 mV) mesenchymal cell lineages. After PEMF exposure, in comparison with ASCs, BM-MSCs showed an increase in cell proliferation (p

Several new methods have been developed in the field of biotechnology to obtain autologous cellular suspensions during surgery, in order to provide one step treatments for acute and chronic skin lesions. Moreover, the management of chronic but also acute wounds resulting from trauma, diabetes, infections and other causes, remains challenging. In this study we describe a new method to create autologous micro-grafts from cutaneous tissue of a single patient and their clinical application. Moreover, in vitro biological characterization of cutaneous tissue derived from skin, de-epidermized dermis (Ded) and dermis of multi-organ and/or multi-tissue donors was also performed. All tissues were disaggregated by this new protocol, allowing us to obtain viable micro-grafts. In particular, we reported that this innovative protocol is able to create bio-complexes composed by autologous micro-grafts and collagen sponges ready to be applied on skin lesions. The clinical application of autologous bio-complexes on a leg lesion was also reported, showing an improvement of both re-epitalization process and softness of the lesion. Additionally, our in vitro model showed that cell viability after mechanical disaggregation with this system is maintained over time for up to seven (7) days of culture. We also observed, by flow cytometry analysis, that the pool of cells obtained from disaggregation is composed of several cell types, including mesenchymal stem cells, that exert a key role in the processes of tissue regeneration and repair, for their high regenerative potential. Finally, we demonstrated in vitro that this procedure maintains the sterility of micro-grafts when cultured in Agar dishes. In summary, we conclude that this new regenerative approach can be a promising tool for clinicians to obtain in one step viable, sterile and ready to use micro-grafts that can be applied alone or in combination with most common biological scaffolds.

The periosteum is a specialized connective tissue containing multipotent stem cells capable of bone formation. In this study, we aimed at demonstrating that human oral periosteal cells derived from three different oral sites (upper vestibule, lower vestibule, and hard palate) represent an innovative cell source for maxillo-facial tissue engineering applications in terms of accessibility and self-commitment towards osteogenic lineage. Periosteal cells (PCs) were isolated from patients with different ages (20-30 yy, 40-50 yy, 50-60 yy); we then analyzed the in vitro proliferation capacity and the bone self-commitment of cell clones culturing them without any osteogenic supplement to support their differentiation. We found that oral PCs, independently of their origin and age of patients, are mesenchymal stem cells with stem cell characteristics (clonogenical and proliferative activity) and that, even in absence of any osteogenic induction, they undertake the osteoblast lineage after 45 days of culture. These results suggest that oral periosteal cells could replace mesenchymal cells from bone marrow in oral tissue-engineering applications.

Conditions such as muscular dystrophies (MDs) that affect both cardiac and skeletal muscles would benefit from therapeutic strategies that enable regeneration of both of these striated muscle types. Protocols have been developed to promote induced pluripotent stem cells (iPSCs) to differentiate toward cardiac or skeletal muscle; however, there are currently no strategies to simultaneously target both muscle types. Tissues exhibit specific epigenetic alterations; therefore, source-related lineage biases have the potential to improve iPSC-driven multilineage differentiation. Here, we determined that differential myogenic propensity influences the commitment of isogenic iPSCs and a specifically isolated pool of mesodermal iPSC-derived progenitors (MiPs) toward the striated muscle lineages. Differential myogenic propensity did not influence pluripotency, but did selectively enhance chimerism of MiP-derived tissue in both fetal and adult skeletal muscle. When injected into dystrophic mice, MiPs engrafted and repaired both skeletal and cardiac muscle, reducing functional defects. Similarly, engraftment into dystrophic mice of canine MiPs from dystrophic dogs that had undergone TALEN-mediated correction of the MD-associated mutation also resulted in functional striatal muscle regeneration. Moreover, human MiPs exhibited the same capacity for the dual differentiation observed in murine and canine MiPs. The findings of this study suggest that MiPs should be further explored for combined therapy of cardiac and skeletal muscles. ispartof: Journal of Clinical Investigation vol:125 issue:12 pages:4463-4482 ispartof: location:United States status: published

In order to verify whether differentiation of adult stem cells toward bone tissue is promoted by high-frequency vibration (HFV), bone marrow stromal cells (BMSCs) were mechanically stimulated with HFV (30 Hz) for 45 minutes a day for 21 or 40 days. Cells were seeded in osteogenic medium, which enhances differentiation towards bone tissue. The effects of the mechanical treatment on differentiation were measured by Alizarin Red test, (q) real-time PCR, and protein content of the extracellular matrix. In addition, we analyzed the proliferation rate and apoptosis of BMSC subjected to mechanical stimulation. A strong increase in all parameters characterizing differentiation was observed. Deposition of calcium was almost double in the treated samples; the expression of genes involved in later differentiation was significantly increased and protein content was higher for all osteogenic proteins. Lastly, proliferation results indicated that stimulated BMSCs have a decreased growth rate in comparison with controls, but both treated and untreated cells do not enter the apoptosis process. These findings could reduce the gap between research and clinical application for bone substitutes derived from patient cells by improving the differentiation protocol for autologous cells and a further implant of the bone graft into the patient.

Skeletal muscle is one of the most plastic tissues of vertebrates since it may able upon exercises to double in size due to a physiological hypertrophy. Despite the fact that it is mainly a syncytial tissue, it contains a relevant number of mononucleated cells that can be involved in its homeostasis and repair. Although the mononuclear cell types with the highest myogenic potential are the satellite cells located underneath the basal lamina of muscle fibres, other interstitial cells have been shown to contribute to muscle regeneration. Adding complexity to this scenario is the fact that several authors revealed myogenic potential in pluripotent stem cells, which can be generated from patient somatic cells and eventually manipulated to correct the genetic defect. Notwithstanding the copiousness of myogenic cell types, their use in ex vivo cell therapies for muscular degenerative diseases is still questionable. However, new discovers on their biological properties have advanced our comprehension in handling myogenic stem cells significantly. In this review, we will focus on the myogenic potential of multi- and pluri-potent stem cells and their use in preclinical and clinical studies. New insights from direct reprogramming and epigenetic signalling to generate myogenic stem cells are also considered.

Three-dimensional (3D) titanium-6-aluminium-4-vanadium (Ti6Al4V) is a widely used biomaterial for orthopedic prosthesis and dental implants; thanks to its very high-mechanical strength and resistance to corrosion. Human mesenchymal stem cells (hMSCs) and dental pulp stem cells (hDPSCs) are responsible for bone regeneration following colonization of prosthesis or dental implants. Both hMSCs and hDPSCs have lower ability to colonize this biomaterial in comparison with tissue culture-treated plastic. Both hMSCs and hDPSCs show lack of focal adhesion kinase (FAK) activation when grown on Ti6Al4V. This signal is restored in the presence of poly-L-lysine (poly-L-lys). Poly-L-lys has been used as part of organoapatite or together with zinc and calcium ions. Our results suggest that poly-L-lys alone induces FAK activation through β1-INTEGRIN, because the presence of β1-INTEGRIN blocking antibody avoided FAK autophosphorylation. Presence of poly-L-lys also increases expression of osteoblastic differentiation marker genes in hMSCs and hDPSCs grown on Ti6Al4V.