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IntroductionAmong the elderly, the availability of tool assessing psychosomatic syndromes is limited. The present study aims at testing inter-rater reliability and concurrent validity of the semi-structured interview for the Diagnostic Criteria for Psychosomatic Research (DCPR-R-SSI) in the elderly of the general population. MethodOne hundred eight subjects were recruited. Participants received a clinical assessment which included the DCPR-R-SSI, the Illness Attitude Scale (IAS), the Geriatric Depression Scale (GDS), the Psychosocial Index (PSI), the Toronto Alexithymia Scale-20 (TAS-20). Analyses of inter-rater reliability of DCPR-R-SSI and concurrent validity between DCPR-R-SSI and self-administered questionnaires were conducted. ResultsDCPR-R-SSI showed excellent inter-rater reliability with a percent of agreement of 90.7% (K Cohen: 0.856 [SE = 0.043], 95% CI: 0.77-0.94). DCPR-R demoralization showed fair concurrent validity with GDS; concurrent validity was also fair between DCPR-R Alexithymia and TAS-20, and between DCPR-R allostatic overload and PSI allostatic load, while the concurrent validity between DCPR-R Disease Phobia and IAS was moderate. ConclusionDCPR-R-SSI represents a reliable and valid tool to assess psychosomatic syndromes in the elderly. DCPR-R is in need of being implemented in the elderly clinical evaluation.

INTRODUCTION: According to the revised version of the Diagnostic Criteria for Psychosomatic Research (DCPR-R), this study explored the prevalence and clinical correlates of DCPR-R psychosomatic syndromes in the elderly and tested whether DCPR-R provide an incremental contribution to the prediction of psychosocial functioning over and above DSM-5.METHOD: One hundred seven elderly subjects were recruited. Participants received a clinical assessment, which included the DCPR-Revised Semi-Structured Interview (DCPR-R SSI), the Structured Clinical Interview for DSM-5-Clinician Version (SCID-5-CV), the Psychological Well-Being (PWB) Scales, the Geriatric Anxiety Scale (GAS) and the Geriatric Depression Scale (GDS). Analyses of covariance (ANCOVA) and hierarchical regression analyses were run.RESULTS: Twenty-two (20.6%) subjects had at least one DSM-5 diagnosis, and 62 (57.9%) reported at least one DCPR-R diagnosis. Subjects with at least one DCPR-R diagnosis showed lower PWB Personal Growth and PWB Purpose in Life than those without DCPR-R diagnoses. When the incremental validity of the DCPR-R was tested using PWB Personal Growth, PWB Purpose in Life, PWB Self-acceptance, GAS Cognitive symptoms and GAS affective symptoms subscales as criterion variable, the DCPR-R increased up to 0.135-0.263 the explained variance.CONCLUSION: The DCPR-R might be implemented together with the DSM-5 to have a comprehensive assessment of elderly subjects.

Gastrulation is a stage in embryo development where three germ layers arise to dictate the human body plan. In vitro models of gastrulation have been demonstrated by treating pluripotent stem cells with soluble morphogens to trigger differentiation. However, in vivo gastrulation is a multistage process coordinated through feedback between soluble gradients and biophysical forces, with the multipotent epiblast transforming to the primitive streak followed by germ layer segregation. Here, the authors show how constraining pluripotent stem cells to hydrogel islands triggers morphogenesis that mirrors the stages preceding in vivo gastrulation, without the need for exogenous supplements. Within hours of initial seeding, cells display a contractile phenotype at the boundary, which leads to enhanced proliferation, yes-associated protein (YAP) translocation, epithelial to mesenchymal transition, and emergence of SRY-box transcription factor 17 (SOX17)

Geometry is an important aspect of the environment surrounding cells and tissues. Often the chemical and physical aspects of the environment will dictate a corresponding topography that gives rise to a host of connected activities. Microengineering materials have been widely used for a variety of biomedical applications, including protein biosensors and microarrays, cell-based drug screening, and fundamental cell biology (cell–cell, cell–matrix, and cell–factor interaction) and applied tissue engineering. The platforms employed to control the shape of cells and tissues are diverse and often vary according to the context of the application or necessary materials. In this chapter, we provide an overview of state-of-the-art microengineering techniques used for cell and tissue micropatterning, along with a description of how they are applied to a variety of cell and biomaterial types.

Structurally, bone tissue is an inorganic-organic composite containing metabolically active cells embedded within a hierarchical, highly mineralized matrix. This organization is challenging to replicate due to the heterogeneous environment of bone. Ceramic omnidirectional bioprinting in cell-suspensions (COBICS) is a microgel-based bioprinting technique that uniquely replicates the mineral and cellular structure of bone. COBICS prints complex, biologically relevant constructs without the need for sacrificial support materials or harsh postprocessing steps (e.g., radiation and high-temperature sintering), which are two of the biggest challenges in the additive manufacturing of bone mimetic constructs. This technique is enabled via the freeform extrusion of a novel calcium phosphate-based ink within a gelatin-based microgel suspension. The yield-stress properties of the suspension allow deposition and support the printed bone structure. UV crosslinking and nanoprecipitation then "lock" it in place. The ability to print nanostructured bone-mimetic ceramics within cell-laden biomaterials provides spatiotemporal control over macro- and micro-architecture and facilitates the real-time fabrication of complex bone constructs in clinical settings.

Mesenchymal stem cell therapy has suffered from wide variability in clinical efficacy, largely due to heterogeneous starting cell populations and large-scale cell death during and after implantation. Optimizing the manufacturing process has led to reproducible cell populations that can be cryopreserved for clinical applications. Nevertheless, ensuring a reproducible cell state that persists after cryopreservation remains a significant challenge, and is necessary to ensure reproducible clinical outcomes. Here we demonstrate how matrix-conjugated hydrogel cell culture materials can normalize a population of induced pluripotent stem cell derived mesenchymal stem cells (iPSC-MSCs) to display a defined secretory profile that promotes enhanced neovascularization in vitro and in vivo. Using a protein-conjugated biomaterials screen we identified two conditions-1 kPa collagen and 10 kPa fibronectin coated polyacrylamide gels-that promote reproducible secretion of pro-angiogenic and immunomodulatory cytokines from iPSC-MSCs that enhance tubulogenesis of endothelial cells in Geltrex and neovascularization in chick chorioallantoic membranes. Using defined culture substrates alone, we demonstrate maintenance of secretory activity after cryopreservation for the first time. This advance provides a simple and scalable approach for cell engineering and subsequent manufacturing, toward normalizing and priming a desired cell activity for clinical regenerative medicine.

Introduction:We here present our findings on 2 types of feeder layers, one composed of mouse embryonic fibroblasts (MEF) and the second one of mouse skeletal myoblasts (C2Cl2) feeder cells.Methods:The 2 feeder layers present a dramatic variance of intrinsic stiffness (142.68 ± 17.21 KPa and 45.78 ± 9.81 KPa, respectively).Results and Conclusion:This information could be used for a better understanding of cells and cell microenvironment mechano-physical characteristics that are influencing stem cell commitment, in order to develop a suitable engineered tissue for cardiac and skeletal muscle repair and a bio-actuator.

Objective.The Diagnostic Criteria for Psychosomatic Research (DCPR) are those of psychosomatic syndromes that did not find room in the classical taxonomy. More recently, the DCPR were updated, called DCPR-revised (DCPR-R). The present study was conducted to test the criterion-related validity of the DCPR-R.Methods.Two hundred consecutive subjects were enrolled at the Headache Center of Careggi University Hospital (Italy): 100 subjects had a diagnosis of chronic migraine (CM) and 100 had a diagnosis of episodic migraine (EM). Participants received a clinical assessment, which included the DCPR-revised Semi-Structured Interview (DCPR-R SSI), the Structured Clinical Interview for DSM-5 (SCID-5), and the psychosocial index (PSI).Results.Forty-seven subjects (23.5%) had at least one DSM-5 diagnosis: major depressive disorder (8.5%; n = 17) and agoraphobia (7.5%; n = 15) were the most frequent. One hundred and ten subjects (55%) reported a DCPR-R diagnosis: allostatic overload (29%; n = 58) and type A behavior (10.5%; n = 21) were the most frequent. When the incremental validity of the DCPR system over the DSM system was tested using PSI subscales as the criterion variable, the DCPR-R increased up to 0.11–0.24 the amount of explained variance. Subjects with at least one DCPR-R diagnosis showed lower PSI well-being scores (p = .001), higher PSI stress scores (p < .001), and higher PSI psychological distress scores (p = .008) than subjects without a DCPR-R diagnosis.Conclusion. The DCPR-R showed a good criterion-related validity in migraine outpatients. Thus, they might be implemented, together with the DSM-5, in the assessment of migraine subjects.

Background Withdrawal syndromes can occur after dose reduction or discontinuation of selective serotonin reuptake inhibitors (SSRIs) or serotonin-norepinephrine reuptake inhibitors (SNRIs). Few measurement instruments are available to assess them: Diagnostic Clinical Interview for Drug Withdrawal 1-New Symptoms of SSRI and SNRI (DID-W1) and Discontinuation Emergent Signs and Symptoms (DESS) checklist. We assessed their interrater reliability, verified the percent agreement between the two, and tested DESS sensitivity and specificity on the basis of the diagnoses formulated via the DID-W1. Methods One-hundred thirty-four subjects who referred for withdrawal at 3 outpatient facilities were enrolled and assessed via the DESS and the DID-W1. Percent agreement and Cohen kappa were calculated to measure DID-W1 and DESS interrater reliability, as well as the agreement between DID-W1 and DESS items. Sensitivity and specificity of DESS were derived from the identification of true-positive, false-negative, true-negative, and false-positive on the DID-W1. Results Both tools showed excellent interrater reliability (DID-W1 Cohen kappa = 0.958; DESS Cohen kappa = 0.81-1). The degree of agreement between DID-W1 and DESS items was poor or fair (Cohen kappa < 0.40) for some items and moderate (Cohen kappa = 0.41-0.60) for others. Sensitivity and specificity of DESS were 0.937 (true-positive = 60, false-negative = 4) and 0.285 (true-negative = 20, false-positive = 50), respectively. Conclusions DID-W1 was a reliable method to identify and diagnose withdrawal syndromes. The DESS checklist showed to be a useful tool for detecting withdrawal SSRI/SNRI symptoms when the aim is to achieve high sensitivity to identify true positives.

Embryogenesis is orchestrated through local morphogen gradients and endometrial constraints that give rise to the three germ layers in a well-defined assembly. In vitro models of embryogenesis have been demonstrated by treating pluripotent stem cells in adherent or suspension culture with soluble morphogens and small molecules, which leads to tri-lineage differentiation. However, treatment with exogenous agents override the subtle spatiotemporal changes observed in vivo that ultimately underly the human body plan. Here we demonstrate how microconfinement of pluripotent stem cells on hydrogel substrates catalyses gastrulation-like events without the need for supplements. Within six hours of initial seeding, cells at the boundary show elevated cytoskeletal tension and yes-associated protein (YAP) activity, which leads to changes in cell and nuclear morphology, epithelial to mesenchymal transition, and emergence of defined patterns of primitive streak containing SRY-Box Transcription Factor 17 (SOX17)+ T/BRACHYURY+ cells. Immunofluorescence staining, transcript analysis, and the use of pharmacological modulators reveal a role for mechanotransduction-coupled non-canonical wingless-type (WNT) signalling in promoting epithelial to mesenchymal transition and multilayered organization within the colonies. These microscale gastruloids were removed from the substrate and encapsulated in 3D hydrogels, where biomaterials properties correspond to maintenance and spatial positioning of the primitive streak. Together, this approach demonstrates how materials alone can nurture embryonic gastrulation, thereby providing an in vitro model of early development.

Photochemical tissue bonding with chitosan-based adhesive films is an experimental surgical technique that avoids the risk of thermal tissue injuries and the use of sutures to maintain strong tissue connection. This technique is advantageous over other tissue repair methods as it is minimally invasive and does not require mixing of multiple components before or during application. To expand the capability of the film to beyond just a tissue bonding device and promote tissue regeneration, in this study, we designed bioadhesive films that could also support stem cells. The films were modified with oligomeric chitosan to tune their erodibility and made porous through freeze-drying for better tissue integration. Of note, porous adhesive films (pore diameter ∼110 μm), with 10% of the chitosan being oligomeric, could retain similar tissue bonding strengths (13-15 kPa) to that of the nonporous chitosan-based adhesives used in previous studies when photoactivated. When tested in vitro, these films exhibited a mass loss of ∼20% after 7 days, swelling ratios of ∼270-300%, a percentage elongation of ∼90%, and both a tensile strength and Young's modulus of ∼1 MPa. The physical properties of the films were suitable for maintaining the viability and multipotency of bone-marrow-derived human mesenchymal stem cells over the duration of culture. Thus, these biocompatible, photoactivated porous, and erodible adhesive films show promise for applications in controlled cell delivery and regenerative medicine.

Musculoskeletal conditions, due to trauma, disease, or congenital defects, can compromise the skeletal system. The emergence of 3D bioprinting techniques alongside the advent of induced pluripotent stem cells (iPSCs) opens the door to new opportunities in regenerative medicine for musculoskeletal conditions. During recent years the collective research outcomes have demonstrated the ability to generate disease-specific human iPSCs (hiPSCs), and to differentiate them into relevant tissues, providing opportunities for disease modeling and patient-specific drug development. Here we review the current status of using iPSCs with bioprinting techniques for fabrication and regeneration of musculoskeletal tissues, and highlight major challenges and future scope. First, we consider the different protocols available for differentiating iPSCs into either of the three tissues. We then highlight studies that have used iPSCs in combination with bioprinting techniques to develop engineered constructs for musculoskeletal tissues. Finally, we provide perspective for future research at the intersection of bioprinting and iPSC differentiation, and the emerging opportunities to leverage these complementary technologies for regenerative medicine.

Background aims Mesenchymal stromal cells (MSCs) have been shown to improve cardiac function after injury and are the subject of ongoing clinical trials. In this study, the authors tested the cardiac regenerative potential of an induced pluripotent stem cell-derived MSC (iPSC-MSC) population (Cymerus MSCs) in a rat model of myocardial ischemia-reperfusion (I/R). Furthermore, the authors compared this efficacy with bone marrow-derived MSCs (BM-MSCs), which are the predominant cell type in clinical trials. Methods Four days after myocardial I/R injury, rats were randomly assigned to (i) a Cymerus MSC group (n = 15), (ii) a BM-MSC group (n = 15) or (iii) a vehicle control group (n = 14). For cell-treated animals, a total of 5 × 106 cells were injected at three sites within the infarcted left ventricular (LV) wall. Results One month after cell transplantation, Cymerus MSCs improved LV function (assessed by echocardiography) compared with vehicle and BM-MSCs. Interestingly, Cymerus MSCs enhanced angiogenesis without sustained engraftment or significant impact on infarct scar size. Suggesting safety, Cymerus MSCs had no effect on inducible tachycardia or the ventricular scar heterogeneity that provides a substrate for cardiac re-entrant circuits. Conclusions The authors here demonstrate that intra-myocardial administration of iPSC-MSCs (Cymerus MSCs) provide better therapeutic effects compared with conventional BM-MSCs in a rodent model of myocardial I/R. Because of its manufacturing scalability, iPSC-MSC therapy offers an exciting opportunity for an “off-the-shelf” stem cell therapy for cardiac repair.

The discovery of induced pluripotent stem cells (iPSCs), reprogrammed to pluripotency from somatic cells, has transformed the landscape of regenerative medicine, disease modelling and drug discovery pipelines. Since the first generation of iPSCs in 2006, there has been enormous effort to develop new methods that increase reprogramming efficiency, and obviate the need for viral vectors. In parallel to this, the promise of in vivo reprogramming to convert cells into a desired cell type to repair damage in the body, constitutes a new paradigm in approaches for tissue regeneration. This review article explores the current state of reprogramming techniques for iPSC generation with a specific focus on alternative methods that use biophysical and biochemical stimuli to reduce or eliminate exogenous factors, thereby overcoming the epigenetic barrier towards vector-free approaches with improved clinical viability. We then focus on application of iPSC for therapeutic approaches, by giving an overview of ongoing clinical trials using iPSCs for a variety of health conditions and discuss future scope for using materials and reagents to reprogram cells in the body.

Purpose/aim of study: Menisectomies account for over 1.5 million surgical interventions in Europe annually, and there is a growing interest in regenerative strategies to improve outcomes in meniscal replacement. The overall objective of this study was to evaluate the role of intraoperatively applied fresh chondrocyte (FC) isolates compared to minced cartilage (MC) fragments, used without cell isolation, to improve bioactivity and tissue integration when combined with a polyurethane replacement.First, to optimize the intraoperative cell isolation protocol, caprine articular cartilage biopsies were digested with 750 U/ml or 3000 U/ml collagenase type II (ratio of 10 ml per g of tissue) for 30 min, 1 h or 12 h with constant agitation and compared to culture-expanded chondrocytes in terms of matrix deposition when cultured on polyurethane scaffolds. Finally, FCs and MC-augmented polyurethane scaffolds were evaluated in a caprine meniscal explant model to assess the potential enhancements on tissue integration strength.Adequate numbers of FCs were harvested using a 30 min chondrocyte isolation protocol and were found to demonstrate improved matrix deposition compared to standard culture-expanded cells in vitro. Upon evaluation in a meniscus explant defect model, both FCs and MC showed improved matrix deposition at the tissue-scaffold interface and enhanced push-out strength, fourfold and 2.5-fold, respectively, compared with the acellular implant.Herein, we have demonstrated a novel approach that could be applied intraoperatively, using FCs or MC for improved tissue integration with a polyurethane meniscal replacement.

In this review, we summarize the challenges of the three-dimensional (3D) printing of porous bioceramics and their translational hurdles to clinical applications. The state-of-the-art of the major 3D printing techniques (powder-based and slurry-based), their limitations and key processing parameters are discussed in detail. The significant roadblocks that prevent implementation of 3D printed bioceramics in tissue engineering strategies, and medical applications are outlined, and the future directions where new research may overcome the limitations are proposed. In recent years, there has been an increasing demand for a nanoscale control in 3D fabrication of bioceramic scaffolds via emerging techniques such as digital light processing, two-photon polymerization, or large area maskless photopolymerization. However, these techniques are still in a developmental stage and not capable of fabrication of large-sized bioceramic scaffolds; thus, there is a lack of sufficient data to evaluate their contribution. This review will also not cover polymer matrix composites reinforced with particulate bioceramics, hydrogels reinforced with particulate bioceramics, polymers coated with bioceramics and non-porous bioceramics.

Background: The Mental Pain Questionnaire (MPQ) is a self-report questionnaire developed to assess mental pain. The aim of the present study was to test the clinimetric properties of the MPQ.Methods: A sample of 200 migraine outpatients were enrolled; homogeneity of MPQ was assessed by Mokken Analysis; item-level severity and item-level sensitivity were calculated via Two-Parameter Logistic model; Total Information Function was evaluated to assess reliability of MPQ; internal consistency was calculated via Cronbach's alpha and Sijtsma and Molenaar rho; sensitivity and specificity were assessed via Receiver Operating Characteristic curves.Results: The MPQ showed unidimensional factor structure; satisfactory homogeneity of the item and total score, except items 4 ("my pain is everywhere") and 6 ("I cannot understand why I feel this pain"); good discrimination, except item 7 ("I feel empty"); low information provided by items 4, 6, 7; good reliability for mild and high levels of mental pain; poor reliability for low levels of mental pain; acceptable internal consistency; acceptable sensitivity and specificity.Limitations: The sample size is barely sufficient to calculate item parameters; it is a monocentric study that enrolled outpatients from a tertiary facility; the study enrolled migraine outpatients not affected by other medical disease.Conclusions: The MPQ showed good psychometric properties. Items 4, 6, 7 should be considered with caution when migraine patients are evaluated. A score of at least 3 indicates mental pain clinically relevant, a score of at least 2 indicates distress. These data are preliminary and refer to migraine patients, results might be different in psychiatric populations.

Core-shell scaffolds offer a promising regenerative solution to debilitating injuries to anterior cruciate ligament (ACL) thanks to a unique biphasic structure. Nevertheless, current core-shell designs are impaired by an imbalance between permeability, biochemical and mechanical cues. This study aimed to address this issue by creating a porous core-shell construct which favors cell infiltration and matrix production, while providing mechanical stability at the site of injury. The developed core-shell scaffold combines an outer shell of electrospun poly(caprolactone) fibers with a freeze-dried core of type I collagen doped with proteoglycans (biglycan, decorin) or glycosaminoglycans (chondroitin sulphate, dermatan sulphate). The aligned fibrous shell achieved an elastic modulus akin of the human ACL, while the porous collagen core is permeable to human mesenchymal stem cell (hMSC). Doping of the core with the aforementioned biomolecules led to structural and mechanical changes in the pore network. Assessment of cellular metabolic activity and scaffold contraction shows that hMSCs actively remodel the matrix at different degrees, depending on the core's doping formulation. Additionally, immunohistochemical staining and mRNA transcript levels show that the collagen-chondroitin sulphate formulation has the highest matrix production activity, while the collagen-decorin formulation featured a matrix production profile more characteristic of the undamaged tissue. Together, this demonstrates that scaffold doping with target biomolecules leads to distinct levels of cell-mediated matrix remodeling. Overall, this work resulted in the development of a versatile and robust platform with a combination of mechanical and biochemical features that have a significant potential in promoting the repair process of ACL tissue.

In living systems, the extracellular environment is structured in a hierarchal order assembling into tissues in a myriad of shapes and complex geometries. Residing within the extracellular matrix, cells are presented and influenced by geometrical cues at several scales. While there is an emerging body of evidence that substrate with symmetric supra-cellular scale geometries (e.g. cylinders and spheres) influence the cell behavior, the effect of physiologically relevant, non-symmetric geometries with varying mean curvatures remain unexplored. In this study, we systematically explore the migratory and differentiation behavior of adipose derived stem cells (ADSCs) on arrays of elliptical cylinders (up to 80 × cell size) with varying mean curvature made from hydroxyapatite. Here, we report a new substrate-driven cell response, which we term “ridge-effect” that leads to osteogenic differentiation and nuclear deformation of cells adhered on regions of highest mean curvature at the ridge of the elliptical cylinders. This phenomenon is observed in both expansion and osteogenic medium. Live imaging combined with functional analysis shows that cells travel along-side the zero mean curvature direction on elliptical cylinders and significantly promote expression of collagen I and osteocalcin compared to a flat surface, in the absence of osteogenic supplements. Altogether, this work identifies supra-cellular scale topographies, and suggest the “ridge-effect” as a physical cue for guiding cellular mechanoresponse and promoting osteogenic differentiation. This knowledge could be utilized as an important biomaterial design parameter for the development of biomedical interfaces and bone scaffolds in tissue engineering and regenerative medicine.

Recently, the extracellular microenvironment has been shown to be critical for the correct differentiation of stem cells to specific tissues. Many factors, including physical (e.g. biomaterial stiffness and topography) and biological (as growth factors, cytokines and chemokines) components, cooperate to create an ideal microenvironment for muscle stem cells, with many of these factors having been widely investigated. We previously demonstrated that the use of non-proliferating muscle-specific and unrelated cells as feeder layers for skeletal muscle progenitor cell differentiation resulted in significant differences in the ability to form myotubes, suggesting the importance of biological factors in myogenic differentiation. In this study, we investigated the biological factors involved in this process, analyzing the expression profile of 84 genes coding for cytokines and chemokines. We successfully identified a novel role for the cytokine IL-12 in the myogenic differentiation of C2C12 mouse skeletal muscle cells. Experiments involving the overexpression or silencing of the IL-12 gene in C2C12 showed that IL-12 enhanced the myogenic differentiation process. Moreover, when IL-12 was overexpressed in non-biologically related feeder cells, the new co-culture system was able to improve myogenic differentiation of C2C12 seeded on top. Although IL-12 is known to be a cytokine involved in inflammatory responses, it also appears to be involved in the myogenic differentiation process, acting as a positive regulator of this mechanism. This fact is expected to prove to be important for the development of functional biomaterials.

Here, we present a concise review of current 3D bioprinting technologies applied to induced pluripotent stem cells (iPSC). iPSC have recently received a great deal of attention from the scientific and clinical communities for their unique properties, which include abundant adult cell sources, ability to indefinitely self-renew and differentiate into any tissue of the body. Bioprinting of iPSC and iPSC derived cells combined with natural or synthetic biomaterials to fabricate tissue mimicked constructs, has emerged as a technology that might revolutionize regenerative medicine and patient-specific treatment. This review covers the advantages and disadvantages of bioprinting techniques, influence of bioprinting parameters and printing condition on cell viability, and commonly used iPSC sources, and bioinks. A clear distinction is made for bioprinting techniques used for iPSC at their undifferentiated stage or when used as adult stem cells or terminally differentiated cells. This review presents state of the art data obtained from major searching engines, including Pubmed/MEDLINE, Google Scholar, and Scopus, concerning iPSC generation, undifferentiated iPSC, iPSC bioprinting, bioprinting techniques, cartilage, bone, heart, neural tissue, skin, and hepatic tissue cells derived from iPSC.

The contribution of adult stem cells to cardiac repair is mostly ascribed to an indirect paracrine effect, rather than to their actual engraftment and differentiation into new contractile and vascular cells. This effect consists in a direct reduction of host cell death, promotion of neovascularization, and in a “bystander effect” on local inflammation. A number of cytokines secreted by adult stem/progenitor cells has been proposed to be responsible for the consistent beneficial effect reported in the early attempts to deliver different stem cell subsets to the injured myocardium. Aiming to maximize their beneficial activity on the diseased myocardium, the genetic modification of adult stem cells to enhance and/or control the secretion of specific cytokines would turn them into active drug delivery vectors. On the other hand, engineering biocompatible scaffolds as to release paracrine factors could result in multiple advantages: (1) achieve a local controlled release of the drug of interest, thus minimizing off-target effects, (2) enhance stem cell retention in the injured area and (3) boost the beneficial paracrine effects exerted by adult stem cells on the host tissue. In the present review, a critical overview of the state-of-the-art in the modification of stem cells and the functionalization of biocompatible scaffolds to deliver beneficial soluble factors to the injured myocardium is offered. Besides the number of concerns to be addressed before a clinical application can be foreseen for such concepts, this path could translate into the generation of active scaffolds as smart cell and drug delivery systems for cardiac repair.

Stem cell responsiveness to extracellular matrix (ECM) composition and mechanical cues has been the subject of a number of investigations so far, yet the molecular mechanisms underlying stem cell mechano-biology still need full clarification. Here we demonstrate that the paralog proteins YAP and TAZ exert a crucial role in adult cardiac progenitor cell mechano-sensing and fate decision. Cardiac progenitors respond to dynamic modifications in substrate rigidity and nanopattern by promptly changing YAP/TAZ intracellular localization. We identify a novel activity of YAP and TAZ in the regulation of tubulogenesis in 3D environments and highlight a role for YAP/TAZ in cardiac progenitor proliferation and differentiation. Furthermore, we show that YAP/TAZ expression is triggered in the heart cells located at the infarct border zone. Our results suggest a fundamental role for the YAP/TAZ axis in the response of resident progenitor cells to the modifications in microenvironment nanostructure and mechanics, thereby contributing to the maintenance of myocardial homeostasis in the adult heart. These proteins are indicated as potential targets to control cardiac progenitor cell fate by materials design.

To maximize the therapeutic efficacy of cardiac muscle constructs produced by stem cells and tissue engineering protocols, suitable scaffolds should be designed to recapitulate all the characteristics of native muscle and mimic the microenvironment encountered by cells in vivo. Moreover, so not to interfere with cardiac contractility, the scaffold should be deformable enough to withstand muscle contraction. Recently, it was suggested that the mechanical properties of scaffolds can interfere with stem/progenitor cell functions, and thus careful consideration is required when choosing polymers for targeted applications. In this study, cross-linked poly-ε-caprolactone membranes having similar chemical composition and controlled stiffness in a supra-physiological range were challenged with two sources of myoblasts to evaluate the suitability of substrates with different stiffness for cell adhesion, proliferation and differentiation. Furthermore, muscle-specific and non-related feeder layers were prepared on stiff surfaces to reveal the contribution of biological and mechanical cues to skeletal muscle progenitor differentiation. We demonstrated that substrate stiffness does affect myogenic differentiation, meaning that softer substrates can promote differentiation and that a muscle-specific feeder layer can improve the degree of maturation in skeletal muscle stem cells.