Muscle acellular scaffold as a biomaterial: effects on C2C12 cell differentiation and interaction with the murine host environment

Functionalized magnesium alloys obtained by superplastic forming process retain osteoinductive and antibacterial properties: An in-vitro study

OBJECTIVES

This study aimed to investigate the biocompatibility, osteogenic and antibacterial activity of biomedical devices based on Magnesium (Mg) Alloys manufactured by Superplastic Forming process (SPF) and subjected to Hydrothermal (HT) and Sol-Gel Treatment (Sol-Gel).

METHODS

Mg-SPF devices subjected to Hydrothermal (Mg-SPF+HT) and Sol-Gel Treatment (Mg-SPF+Sol-Gel) were investigated. The biocompatibility of Mg-SPF+Sol-Gel and Mg-SPF+HT devices was observed by indirect and direct cytotoxicity assays, whereas the colonization of sample surfaces was assessed by confocal microscopy. qRT-PCR analysis and microbial growth curve analyses were employed to evaluate the osteogenic and antibacterial activity of both SPF-Mg treated devices, respectively.

RESULTS

Mg-SPF+HT and Mg-SPF+Sol-Gel showed a high degree of biocompatibility. Analysis of mRNA expression of osteogenic genes in cells cultured on Mg-treated devices revealed a significant upregulation of the expression levels of BMP2 and Runx-2. Furthermore, the bacterial growth in strains developed in contact with both the Mg-SPF+HT and Mg-SPF+Sol-Gel devices was lower than that observed in the control.

SIGNIFICANCE

Hydrothermal and Sol-Gel Treatments of Mg alloys obtained through the SPF process demonstrated bioactive, osteogenic and antibacterial activity, offering a promising alternative to conventional Mg-based devices. The obtained Mg-based materials may have the potential to enhance the tunability of temporary devices in maxillary reconstruction, eliminating the need for second surgeries, and ensuring a good bone reconstruction and a reduced implant failure rate due to bacterial infections.

Clinical Impact of "Real World Data" and Blockchain on Public Health: A Scoping Review

The digitisation of healthcare has allowed a significant rethinking of the previous clinical protocols, improving their interoperability through substantial standardisation. These technological advances have ensured that data are comparable, as they are obtained from 'reliable' and certified processes; however, there are billions of data that are neither structured nor quality-controlled. They are collectively referred to as 'Real World Data' (RWD). Blockchain (BC) is a procedure with specific characteristics and algorithms that ensure that the stored data cannot be tampered with. Nowadays, there is an increasing need to rethink blockchain in a one-health vision, making it more than just a 'repository' of data and information, but rather an active player in the process of data sharing. In this landscape, several scholars have analysed the potential benefits of BC in healthcare, focusing on the sharing and safety of clinical data and its contact tracing applications. There is limited research on this matter; moreover, there is a strategic interest in managing RWD in a reliable and comparable way, despite the lack of knowledge on this topic. Our work aims to analyse systematically the most impacting literature, highlighting the main aspects of BC within the context of the new digital healthcare, and speculating on the unexpressed potential of RWD.

Secretome of Dental Pulp-Derived Stem Cells Reduces Inflammation and Proliferation of Glioblastoma Cells by Deactivating Mapk-Akt Pathway

Background

Dental pulp-derived stem cells (DPSC) is a promising therapy as they modulate the immune response, so we evaluated the inhibitory effect of DPSC secretome (DPSC℗) on the proliferation and inflammation in human glioblastoma (GBM) cells (U-87 MG) and elucidated the concomitant mechanisms involved.

Methods

The U87-MG cells were cultured with DPSC℗ for 24 h and assessed the expression of inflammatory molecules using quantitative reverse transcription-polymerase chain reaction (qRT-PCR), generation of reactive oxygen species (ROS), and mitochondrial functionality using a seahorse flux analyzer. MTT (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide) assay and cell cycle analysis were performed to evaluate the proliferation and cell cycle. Finally, the protein levels were determined by western blot.

Results

DPSC℗ reduced the inflammation and proliferation of U-87 MG cells by down-regulating the pro-inflammatory markers and up-regulating anti-inflammatory markers expressions through ROS-mediated signaling. Moreover, DPSC℗ significantly reduced the mitochondrial membrane potential (MMP) in the cells. The cellular bioenergetics revealed that all the parameters of oxygen consumption rate (OCAR) and the extracellular acidification rate (ECAR) were significantly decreased in the GBM cells after the addition of DPSC℗. Additionally, DPSC℗ decreased the GBM cell proliferation by arresting the cell cycle at the G1 phase through activation (phosphorylation) of checkpoint molecule CHK1. Furthermore, mechanistically, we found that the DPSC℗ impedes the phosphorylation of the mitogen-activated protein kinases (P38 MAPK) and protein kinase B (AKT) pathway.

Conclusion

Our findings lend the first evidence of the inhibitory effects of DPSC℗ on proliferation and inflammation in GBM cells by altering the P38 MAPK-AKT pathway.

Advances in Dental Implants, Tissue Engineering and Prosthetic Materials

Scientific research has achieved numerous milestones in the field of materials applied to medicine for biomedical prosthetics [...].

A Double Cross-Linked Injectable Hydrogel Derived from Muscular Decellularized Matrix Promotes Myoblast Proliferation and Myogenic Differentiation

Injectable hydrogels possess tremendous merits for use in muscle regeneration; however, they still lack intrinsic biological cues (such as the proliferation and differentiation of myogenic cells), thus considerably restricting their potential for therapeutic use. Herein, we developed a double cross-linked injectable hydrogel composed of methacrylamidated oxidized hyaluronic acid (MOHA) and muscular decellularized matrix (MDM). The chemical composition of the hydrogel was confirmed using 1H NMR and Fourier transform infrared spectroscopy. To achieve cross-linking, the aldehyde groups in MOHA were initially reacted with the amino groups in MDM through a Schiff-based reaction. This relatively weak cross-linking provided the MOHA/MDM hydrogel with satisfactory injectability. Furthermore, the methacrylation of MOHA facilitated a second cross-linking mechanism via UV irradiation, resulting in improved gelation ability, biomechanical properties, and swelling performance. When C2C12 myogenic cells were loaded into the hydrogel, our results showed that the addition of MDM significantly enhanced myoblast proliferation compared to the MOHA hydrogel, as demonstrated by live/dead staining and Cell Counting Kit-8 assay after seven days of in vitro cultivation. In addition, gene expression analysis using quantitative polymerase chain reaction indicated that the MOHA/MDM hydrogel promoted myogenic differentiation of C2C12 cells more effectively than the MOHA hydrogel, as evidenced by elevated expression levels of myogenin, troponin T, and MHC in the MOHA/MDM hydrogel group. Moreover, after four to eight weeks of implantation in a full-thickness abdominal wall-defect model, the MOHA/MDM hydrogel could promote the reconstruction and repair of functional skeletal muscle tissue with enhanced tetanic force and tensile strength. This study provides a new double cross-linked injectable hydrogel for use in muscular tissue engineering.

Unlocking the Potential of Dental-Derived Mesenchymal Stem Cells in Regenerative Medicine

Over the past few decades, life expectancy has been increasing in several countries [...].

Potential impact of functional biomolecules-enriched foods on human health: A randomized controlled clinical trial

Naturally occurring milk compounds have recently been investigated for their health-promoting properties; in fact, their anti-microbial, immuno-modulatory, antioxidant and anti-thrombotic activities, have increasingly gained interest within the scientific community. We have reported a translational, randomized, controlled clinical trial (RCT) on human subjects with a moderate to high cardiovascular risk, and a body mass index (BMI) >25.1 kg/m2, to evaluate the clinical impact of biomolecules-enriched Mediterranean Buffalo (Bubalus bubalis) milk and its derived dairy foods, produced with innovative breeding techniques. The experimental arm involved patients that followed a diet including the above-described products (treated group; n= 11); the control arm was based on a diet including cow milk and its dairy products (control group; n= 9). The results of this study have been statistically evaluated, pointing out a specific significance related to the comparative analysis of the blood pressure among the 2 arms; in fact, this value showed a significant improvement in an extremely short experimental time. Nevertheless, this study also reported not-significant results that were indicative of an interesting and promising tendency in modulating specific diet-depending haematological and biomedical values. In conclusion, this RCT has assessed that the foods derived from buffalo milk naturally enriched with biomolecules, was able to improve the overall blood glucose levels, the BMI and the body weight. These preliminary results are suitable for the design of future strategies in the prevention of cardiometabolic diseases, thus improving the overall quality of life and the policies of healthcare management.

Rehabilitation of the Completely Edentulous Mandible by All-on-Four Treatment Concept: A Retrospective Cohort Study with Up to 10 Years Follow-Up

(1) Background and Objectives. Currently, there are no definitive long-term data about clinically significant difference in the failure of prosthesis and implant or marginal bone loss related to the rehabilitation of the completely edentulous mandible by all-on-four treatment concept. The main aim of present investigation was to report the long-term outcomes (10-years follow-up) of complete-arch mandibular rehabilitations based on the all-on-four concept. (2) Materials and Methods. Patients in need of extractions of teeth due to the occurrence of caries and/or severe periodontal disease and patients presented with edentulous mandibles were enrolled to the study. A total of 96 participants (mean follow-up period after intervention of 3185.2 days) were enrolled in the study. Participants were evaluated at the first visit, 10 days after intervention and every year after the intervention. Implant and prosthesis survival, bone loss and both local biological and mechanical complications were evaluated during the follow-up period. (3) Results. An implants’ survival rate of 97.9% was observed at the end of the follow-up period. Biological complications were reported in 19.8% of patients, whereas mechanical complications were reported in 27.1% of cases. The average marginal bone level at baseline was −0.03 mm. A significant marginal bone loss was observed after 10-years follow-up (2.5 mm). Binary logistic regression analysis showed significant association between smoke and both marginal bone loss and local biological complications. Lastly, a significant association was observed between bruxism and mechanical complications. (4) Conclusions. The high implant and prosthesis survival rate and the moderate incidence of biological and mechanical complications observed in present investigation can be associated to several factors such as high implant primary stability, prosthetic design, and control of the occlusal forces.

Comparison between placental and skeletal muscle ECM: in vivo implantation

PURPOSE OF THE STUDY

Several tissues have been decellularized and their extracellular matrices used as allogeneic or xenogeneic scaffolds, either in orthotopic or heterotopic implantations, for tissue engineering purposes. Placentas have abundant matrix, extensive microvascular structure, immunomodulatory properties, growth factors and are discarded after birth, representing an interesting source of extracellular matrix. This study aimed at comparing decellularized canine placentas and murine skeletal muscles to regenerate skeletal muscles in a rat model.

MATERIALS AND METHODS

Muscle pockets were created at the posterior limbs of male Wistar rats, where the muscle- and placenta-derived extracellular matrices were implanted. Macroscopic, histological, and immunohistochemical analyses were performed after 3, 15, and 45 days of surgeries.

RESULTS

On the third day, intense inflammatory reaction, with macrophages (CD163⁺) and proliferative cells (PCNA⁺) being observed in control group and adjacent to the decellularized matrices. The percentage of proliferative cells was higher in placenta than in muscle matrices. Macrophages CD163^{+ high} were higher in muscles than in placentas, whereas CD163^{+ low} were higher in placentas than in muscle ECM, at days 3 and 15. Placental matrices were not completely degraded at day 15, as opposed to the muscular ones. After 45 days, both matrices were resorbed and morphologically normal myofibers, with reduction of cell infiltration, were observed.

CONCLUSIONS

These results demonstrated that xenogeneic placental ECM, implanted heterotopically (representing a biologically critical and challenging microenvironment), induced local inflammatory reactions similar to the allogeneic muscle ECM, implanted orthotopically. Thus, placenta-derived extracellular matrix must be further explored in regenerative medicine.

Aligned Poly(ε-caprolactone) Nanofibers Superimposed on Decellularized Human Amniotic Membrane Promoted Myogenic Differentiation of Adipose Derived Stem Cells

Objective

This study was designed to fabricate a suitable permanent scaffold for the normal aligned myotube formation and improve the process of myogenic differentiation of selected stem cells.

Materials and Methods

In this experimental study, an engineered scaffold composed of decellularized human amniotic membrane (DHAM) and electrospun fibers of poly(ε-caprolactone) (PCL) was fabricated and characterized. PCL nanofibers were superimposed on DHAM (PCL-DHAM) in two different patterns, including randomized fibers (Random) and aligned fibers (Aligned). Adipose derived stem cells (ADSCs) were isolated from adult Wistar rats and cultured on designed scaffold and induced to myotube differentiation. Using an MTT assay, the vitality of cells was determined. Then, myogenic cell differentiation was assessed using scan electron microscopy (SEM), immunofluorescence assay, and reverse transcription-polymerase chain reaction (RT-PCR).

Results

The mechanical properties of engineered PCL-DHAM composite improved significantly compared to DHAM as a control. The engineered PCL-DHAM promoted cell growth and high expression of myosin, Mhc2 and myogenin and thus enhanced the myotube formation.

Conclusion

These findings revealed that bio-composite membrane prepared from PCL nanofibers and DHAM, may represent a promising biomaterial as a desirable scaffold for applying in the bioengineered muscle repair.

Healthcare Management During a Pandemic: The Other Side of the Coin for the Treatment of Covid-19 Infection

BACKGROUND

World Health Organization (WHO) has increasingly improved the guidelines to tackle the spread of Coronavirus Disease 2019 (COVID-19) among the worldwide population. In this context, each country has introduced specific social, healthcare, political and macroeconomic measures to face COVID pandemic locally.

OBJECTIVE

The general aim of this comparative overview is to highlight the most significant effects of COVID-19 pandemic on the main healthcare systems. Also, we critically analyzed the macroeconomic variables and the most promising solutions to improve both healthcare system and its related risk management, taking into specific consideration the most industrialized countries.

METHOD

The main strategy has been built on a renewed concept of the hospital, rebuilding the old concepts of "triage" and "intensive care". Recently, COVID-19 hospitals have allowed to cater the patients affected by COVID-19. Moreover, the reshaping of several healthcare policies and requirements has led to several positive effects, such as the recruitment of a huge number of human resources in the healthcare systems. Nevertheless, several negative effects have also impacted the communities mostly subjected to infections.

CONCLUSION

Undoubtedly, the national healthcare systems have somehow addressed the people's needs, trying not to neglect the social, healthcare, economic and political aspects. In our overview, we have reported how the different actions taken in the last months, have resulted in different outcomes.

Modified Endoscopic-Assisted Approach for Removal of Ectopic Third Molar in the Maxillary Sinus

This case series describes an alternative approach for removing ectopically erupted tooth in the maxillary sinus using an improved endoscopic approach known as modified endoscopic-assisted sinus surgery (MESS). We reviewed medical charts and radiographs of patients who underwent surgical removal of an ectopic tooth in the maxillary sinus using MESS. The surgical technique consisted of creating a bony window in the maxillary sinus wall with a pre-adapted microplate, which was repositioned after the tooth was removed. For all the patients included in this study, there were no postoperative complications clinically and radiographically. At the time of microplate removal, satisfactory bone regeneration was observed around the bony window margins of the maxillary sinus wall. MESS is an effective technique that modifies and integrates the techniques of the conventional Caldwell-Luc procedure (CLP) and functional endoscopic sinus surgery (FESS) and can be used to remove ectopic tooth in the maxillary sinus by avoiding the risk of postoperative sinus-related complications.

Advanced Glycation End Products Are Retained in Decellularized Muscle Matrix Derived from Aged Skeletal Muscle

Decellularized tissues are biocompatible materials that engraft well, but the age of their source has not been explored for clinical translation. Advanced glycation end products (AGEs) are chemical cross-links that accrue on skeletal muscle collagen in old age, stiffening the matrix and increasing inflammation. Whether decellularized biomaterials derived from aged muscle would suffer from increased AGE collagen cross-links is unknown. We characterized gastrocnemii of 1-, 2-, and 20-month-old C57BL/6J mice before and after decellularization to determine age-dependent changes to collagen stiffness and AGE cross-linking. Total and soluble collagen was measured to assess if age-dependent increases in collagen and cross-linking persisted in decellularized muscle matrix (DMM). Stiffness of aged DMM was determined using atomic force microscopy. AGE levels and the effect of an AGE cross-link breaker, ALT-711, were tested in DMM samples. Our results show that age-dependent increases in collagen amount, cross-linking, and general stiffness were observed in DMM. Notably, we measured increased AGE-specific cross-links within old muscle, and observed that old DMM retained AGE cross-links using ALT-711 to reduce AGE levels. In conclusion, deleterious age-dependent modifications to collagen are present in DMM from old muscle, implying that age matters when sourcing skeletal muscle extracellular matrix as a biomaterial.

Extracellular Matrix Hydrogels Promote Expression of Muscle-Tendon Junction Proteins

Muscle and tendon injuries are prevalent and range from minor sprains and strains to traumatic, debilitating injuries. However, the interactions between these tissues during injury and recovery remain unclear. Three-dimensional tissue models that incorporate both tissues and a physiologically relevant junction between muscle and tendon may help understand how the two tissues interact. Here, we use tissue specific extracellular matrix (ECM) derived from muscle and tendon to determine how cells of each tissue interact with the microenvironment of the opposite tissue resulting in junction specific features. ECM materials were derived from the Achilles tendon and gastrocnemius muscle, decellularized, and processed to form tissue specific pre-hydrogel digests. ECM materials were unique in respect to protein composition and included many types of ECM proteins, not just collagens. After digestion and gelation, ECM hydrogels had similar complex viscosities which were less than type I collagen hydrogels at the same concentration. C2C12 myoblasts and tendon fibroblasts were cultured in tissue-specific ECM conditioned media or encapsulated in tissue-specific ECM hydrogels to determine cell-matrix interactions and the effects on a muscle-tendon junction marker, paxillin. ECM conditioned media had only a minor effect on upregulation of paxillin in cells cultured in monolayer. However, cells cultured within ECM hydrogels had 50-70% higher paxillin expression than cells cultured in type I collagen hydrogels. Contraction of the ECM hydrogels varied by the type of ECM used. Subsequent experiments with varying density of type I collagen (and thus contraction) showed no correlation between paxillin expression and the amount of gel contraction, suggesting that a constituent of the ECM was the driver of paxillin expression in the ECM hydrogels. In addition, the extracellular matrix protein type XXII collagen had similar expression patterns as paxillin, with smaller effect sizes. Using tissue specific ECM allowed for the de-construction of the cell-matrix interactions similar to muscle-tendon junctions to study the expression of MTJ specific proteins.

Human Chondrocytes from Human Adipose Tissue-Derived Mesenchymal Stem Cells Seeded on a Dermal-Derived Collagen Matrix Sheet: Our Preliminary Results for a Ready to Go Biotechnological Cartilage Graft in Clinical Practice

Background

The articular cartilage is unique in that it contains only a single type of cell and shows poor ability for spontaneous healing. Cartilage tissue engineering which uses mesenchymal stem cells (MSCs) and adipose tissue-derived mesenchymal stem cells (AT-MSCs) is considered an attractive treatment for cartilage lesions and osteoarthritis. The establishment of cartilage regenerative medicine is an important clinical issue, but the search for cell sources able to restore cartilage integrity proves to be challenging. The aim of this study was to create cartilage grafts from the combination of AT-MSCs and collagen substrates.

Methods

Mesenchymal stem cells were obtained from human donors' adipose tissue, and collagen scaffold, obtained from human skin and cleaned from blood vessels, adipose tissues, and debris, which only preserve dermis and epidermis, were seeded and cultured on collagen substrates and differentiated to chondrocytes. The obtained chondrocyte extracellular matrix of cartilage was then evaluated for the expression of chondrocyte-/cartilage-specific markers, the Cartilage Oligomeric Matrix Protein (COMP), collagen X, alpha-1 polypeptide (COL10A1), and the Collagen II, Human Tagged ORF Clone (COL2A1) by using the reverse transcription polymerase chain reaction (RT-PCR).

Results

Our findings have shown that the dermal collagen may exert important effects on the quality of in vitro expanded chondrocytes, leading in this way that the influence of collagen skin matrix helps to produce highly active and functional chondrocytes for long-term cartilage tissue regeneration.

Conclusion

This research opens up the possibility of generating cartilage grafts with the precise purpose of improving the existing limitation in current clinical procedures.

3D Printing Decellularized Extracellular Matrix to Design Biomimetic Scaffolds for Skeletal Muscle Tissue Engineering

Functional engineered muscles are still a critical clinical issue to be addressed, although different strategies have been considered so far for the treatment of severe muscular injuries. Indeed, the regenerative capacity of skeletal muscle (SM) results inadequate for large-scale defects, and currently, SM reconstruction remains a complex and unsolved task. For this aim, tissue engineered muscles should provide a proper biomimetic extracellular matrix (ECM) alternative, characterized by an aligned/microtopographical structure and a myogenic microenvironment, in order to promote muscle regeneration. As a consequence, both materials and fabrication techniques play a key role to plan an effective therapeutic approach. Tissue-specific decellularized ECM (dECM) seems to be one of the most promising material to support muscle regeneration and repair. 3D printing technologies, on the other side, enable the fabrication of scaffolds with a fine and detailed microarchitecture and patient-specific implants with high structural complexity. To identify innovative biomimetic solutions to develop engineered muscular constructs for the treatment of SM loss, the more recent (last 5 years) reports focused on SM dECM-based scaffolds and 3D printing technologies for SM regeneration are herein reviewed. Possible design inputs for 3D printed SM dECM-based scaffolds for muscular regeneration are also suggested.

Extracellular Matrix-Based Biomaterials and Their Influence Upon Cell Behavior

Biologic scaffold materials composed of allogeneic or xenogeneic extracellular matrix (ECM) are commonly used for the repair and remodeling of injured tissue. The clinical outcomes associated with implantation of ECM-based materials range from unacceptable to excellent. The variable clinical results are largely due to differences in the preparation of the material, including characteristics of the source tissue, the method and efficacy of decellularization, and post-decellularization processing steps. The mechanisms by which ECM scaffolds promote constructive tissue remodeling include mechanical support, degradation and release of bioactive molecules, recruitment and differentiation of endogenous stem/progenitor cells, and modulation of the immune response toward an anti-inflammatory phenotype. The methods of ECM preparation and the impact of these methods on the quality of the final product are described herein. Examples of favorable cellular responses of immune and stem cells associated with constructive tissue remodeling of ECM bioscaffolds are described.

An overview of advanced biocompatible and biomimetic materials for creation of replacement structures in the musculoskeletal systems: focusing on cartilage tissue engineering

Tissue engineering, as an interdisciplinary approach, is seeking to create tissues with optimal performance for clinical applications. Various factors, including cells, biomaterials, cell or tissue culture conditions and signaling molecules such as growth factors, play a vital role in the engineering of tissues. In vivo microenvironment of cells imposes complex and specific stimuli on the cells, and has a direct effect on cellular behavior, including proliferation, differentiation and extracellular matrix (ECM) assembly. Therefore, to create appropriate tissues, the conditions of the natural environment around the cells should be well imitated. Therefore, researchers are trying to develop biomimetic scaffolds that can produce appropriate cellular responses. To achieve this, we need to know enough about biomimetic materials. Scaffolds made of biomaterials in musculoskeletal tissue engineering should also be multifunctional in order to be able to function better in mechanical properties, cell signaling and cell adhesion. Multiple combinations of different biomaterials are used to improve above-mentioned properties of various biomaterials and to better imitate the natural features of musculoskeletal tissue in the culture medium. These improvements ultimately lead to the creation of replacement structures in the musculoskeletal system, which are closer to natural tissues in terms of appearance and function. The present review article is focused on biocompatible and biomimetic materials, which are used in musculoskeletal tissue engineering, in particular, cartilage tissue engineering.

Molecular analysis of muscle progenitor cells on extracellular matrix coatings and hydrogels

Development of an ex vivo culture system to expand satellite cells, the resident muscle stem cell population, will be necessary for the development of their use as therapeutics. The loss of the niche environment is often cited as the reason that culture results in both the loss of myogenic potential and low re-engraftment rates of these cells. Studies have shown that culture of satellite cells on more elastic substrates maintained their quiescence and potential and increased re-engraftment, but there was limited proliferation. We examined whether substrates composed of extracellular matrix proteins, as either coatings or hydrogels, could support expansion of this population whilst maintaining the potency of these cells. The collagen based hydrogels were very pliant and our studies demonstrate that stiffer substrates are necessary for in vitro proliferation and differentiation of satellite cells, and the ECM composition was not significantly important. Our data further indicates that culture on highly elastic substrates allowed satellite cells to down-regulate myogenic specific transcription factors, resulting in an expression profile similar to a G_alert state. These satellite cells could be subsequently cultured on Matrigel and induced to differentiate. Proliferation and gene expression data further indicated that C2C12 cells are not a good proxy for studies of satellite cell proliferation and differentiation on alternative substrates. STATEMENT OF SIGNIFICANCE: Although biomaterials and muscle stem cell-based therapeutics for muscle loss due to trauma and disease have been studied intensely for the last decade, significant challenges remain; satellite cells lose their myogenic potential after in vitro culture, and do not re-engraft efficiently when delivered to skeletal muscle. We cultured adult mouse derived satellite cells and C2C12 cells on biomimetic, extracellular matrix based, hydrogels and coated plates and carried out a detailed analysis of proliferation, differentiation, and gene expression. These studies were designed to allow for the examination of the roles of both matrix composition and elasticity. The data demonstrated that satellite cells were most affected by elasticity. Examining the expression of lineage and cell cycle specific genes provided important insight into the behavior of both cell types, and point to fundamental differences that affect the interpretation of studies aimed at understanding the in vitro requirements of muscle progenitor cells. Understanding how satellite cells respond to various biochemical and biophysical cues at the molecular level will inform future efforts to design therapeutics for muscle regeneration.

Induced Intermediate Mesoderm Combined with Decellularized Kidney Scaffolds for Functional Engineering Kidney

Background

Chronic kidney disease is a severe threat to human health with no ideal treatment strategy. Mature mammalian kidneys have a fixed number of nephrons, and regeneration is difficult once they are damaged. For this reason, developing an efficient approach to achieve kidney regeneration is necessary. The technology of the combination of decellularized kidney scaffolds with stem cells has emerged as a new strategy; however, in previous studies, the differentiation of stem cells in decellularized scaffolds was insufficient for functional kidney regeneration, and many problems remain.

Methods

We used 0.5% sodium dodecyl sulfate (SDS) to produce rat kidney decellularized scaffolds, and induce adipose-derived stem cells (ADSCs) into intermediate mesoderm by adding Wnt agonist CHIR99021 and FGF9 in vitro. The characteristics of decellularized scaffolds and intermediate mesoderm induced from adipose-derived stem cells were identified. The scaffolds were recellularized with ADSCs and intermediate mesoderm cells through the renal artery and ureter. After cocultured for 10 days, cells adhesion and differentiation was evaluated.

Results

Intermediate mesoderm cells were successfully induced from ADSCs and identified by immunofluorescence and Western blotting assays (OSR1 + , PAX2 +). Immunofluorescence showed that intermediate mesoderm cells differentiated into tubular-like (E-CAD + , GATA3 +) and podocyte-like (WT1 +) cells with higher differentiation efficiency than ADSCs in the decellularized scaffolds. Comparatively, this phenomenon was not observed in induced intermediate mesoderm cells cultured in vitro.

Conclusion

In this study, we demonstrated that intermediate mesoderm cells could be induced from ADSCs and that they could differentiate well after cocultured with decellularized scaffolds.

Muscle fibrosis in the soft palate: Delivery of cells, growth factors and anti-fibrotics

The healing of skeletal muscle injuries after major trauma or surgical reconstruction is often complicated by the development of fibrosis leading to impaired function. Research in the field of muscle regeneration is mainly focused on the restoration of muscle mass while far less attention is paid to the prevention of fibrosis. In this review, we take as an example the reconstruction of the muscles in the soft palate of cleft palate patients. After surgical closure of the soft palate, muscle function during speech is often impaired by a shortage of muscle tissue as well as the development of fibrosis. We will give a short overview of the most common approaches to generate muscle mass and then focus on strategies to prevent fibrosis. These include anti-fibrotic strategies that have been developed for muscle and other organs by the delivery of small molecules, decorin and miRNAs. Anti-fibrotic compounds should be delivered in aligned constructs in order to obtain the organized architecture of muscle tissue. The available techniques for the preparation of aligned muscle constructs will be discussed. The combination of approaches to generate muscle mass with anti-fibrotic components in an aligned muscle construct may greatly improve the functional outcome of regenerative therapies for muscle injuries.

Management of Central Giant Cell Granulomas of the Jaws: An Unusual Case Report with Critical Appraisal of Existing Literature

Central giant cell granuloma (CGCG) is an uncommon, benign but aggressive osteolytic neoplasm of the craniomaxillofacial region, histologically characterized by an abundance of evenly distributed multinucleated giant cells within a sea of spindle-shaped mesenchymal stromal cells, scattered throughout the fibrovascular connective tissue stroma containing areas of hemorrhage. A rapid diagnostic assessment, together with an adequate histopathologic verification, is essential to improve the management and the prognosis of this locally destructive lesion. A rare case of a large destructive CGCG involving the entire right angle of mandible, causing extensive bony resorption, and buccal, medial as well as inferior border cortical expansion with multiple perforations, in a young child is presented. It was treated successfully by enucleation and aggressive curettage followed by peripheral ostectomy preserving the continuity of the mandible. Two adjunctive measures were employed; first, chemical cauterization of the residual bony walls to prevent possible recurrence, for which this tumor is notorious, and second, placement of fresh autologous platelet-rich fibrin within the bony defect to hasten bone fill and reossification, thus obviating the need for a bone graft.

Biological and Mechanical Properties of Platelet-Rich Fibrin Membranes after Thermal Manipulation and Preparation in a Single-Syringe Closed System

Platelet-rich fibrin (PRF) membrane is a three-dimensional biodegradable biopolymer, which consists of platelet derived growth factors enhancing cell adhesion and proliferation. It is widely used in soft and hard tissue regeneration, however, there are unresolved problems with its clinical application. Its preparation needs open handling of the membranes, it degrades easily, and it has a low tensile strength which does not hold a suture blocking wider clinical applications of PRF. Our aim was to produce a sterile, suturable, reproducible PRF membrane suitable for surgical intervention. We compared the biological and mechanical properties of PRF membranes created by the classical glass-tube and those that were created in a single-syringe closed system (hypACT Inject), which allowed aseptic preparation. HypACT Inject device produces a PRF membrane with better handling characteristics without compromising biological properties. Freeze-thawing resulted in significantly higher tensile strength and higher cell adhesion at a lower degradation rate of the membranes. Mesenchymal stem cells seeded onto PRF membranes readily proliferated on the surface of fresh, but even better on freeze/thawed or freeze-dried membranes. These data show that PRF membranes can be made sterile, more uniform and significantly stronger which makes it possible to use them as suturable surgical membranes.

Supplementation with IL-6 and Muscle Cell Culture Conditioned Media Enhances Myogenic Differentiation of Adipose Tissue-Derived Stem Cells through STAT3 Activation

Mature skeletal muscle cells cannot be expanded in culture systems. Therefore, it is difficult to construct an in vitro model for muscle diseases. To establish an efficient protocol for myogenic differentiation of human adipose tissue-derived stem cells (hADSCs), we investigated whether addition of IL-6 and/or myocyte-conditioned media (CM) to conventional differentiation media can shorten the differentiation period. hADSCs were differentiated to myocytes using the conventional protocol or modified with the addition of 25 pg/mL IL-6 and/or C2C12 CM (25% v/v). The expression of MyoD and myogenine mRNA was significantly higher at 5⁻6 days after differentiation using the modified protocol than with the conventional protocol. mRNA and protein expression of myosin heavy chain, a marker of myotubes, was significantly upregulated at 28 and 42 days of differentiation using the modified protocol, and the level achieved after a 4-week differentiation period was similar to that achieved at 6 weeks using the conventional protocol. The expression of p-STAT3 was significantly increased when the modified protocol was used. Similarly, addition of colivelin, a STAT3 activator, instead of IL-6 and C2C12 CM, promoted the myogenic differentiation of ADSCs. The modified protocol improved differentiation efficiency and reduced the time required for differentiation of myocytes. It might be helpful to save cost and time when preparing myocytes for cell therapies and drug discovery.

Decellularized Hydrogels in Bone Tissue Engineering: A Topical Review

Nowadays, autograft and allograft techniques represent the main solution to improve bone repair. Unfortunately, autograft technique is expensive, invasive and subject to infections and hematoma, frequently affecting both donor sites and surgical sites. A recent advance in tissue engineering is the fabrication of cell-laden hydrogels with custom-made geometry, depending on the clinical case. The use of ECM (Extra-Cellular Matrix)-derived Hydrogels from bone tissue is the new opportunity to obtain good results in bone regeneration. Several micro-engineering techniques and approaches are available to fabricate different cell gradients and zonal structures in hydrogels design, in combination with the advancement in biomaterials selection. In this review, we analyse the stereolithografy, the Bio-patterning, the 3D bioprinting and 3D assembly, the Laser-Induced Forward Transfer Bioprinting (LIFT), the Micro-extrusion bioprinting, the promising Electrospinning technology, the Microfluidics and the Micromolding. Several mechanical properties are taken into account for bone regeneration scaffolds. However, each typology of scaffold presents some advantages and some concerns. The research on biomaterials is the most promising for bone tissue engineering: the new biomimetic materials will allow us to obtain optimal results in the next clinical application of basic research.

About stem cell research in dentistry: many doubts and too many pitfalls still affect the regenerative dentistry

Stem cells (SCs) research is one of the most promising approaches to regenerative medicine. Our understanding of SCs biology and their potential role in tissue repairing has notably increased during the last few years. Mesenchymal stem cells (MSCs) are present in almost all human tissues, including oral and dental tissues (dental-derived stem cells or DDSCs). Despite many doubts and too many pitfalls still affect regenerative dentistry; however, it represents an exciting challenge for the next generations of young dentists. Educating and training in regenerative medicine the new generation of researchers is of utmost importance, albeit often underestimated: regenerative dentistry represents a big opportunity for the next generations of researchers and clinicians, and this review report underlines that dental schools should pay more attention to teachings of strategic subjects, such as cell biology, molecular biology and tissue engineering.

Adipose Tissue as a Strategic Source of Mesenchymal Stem Cells in Bone Regeneration: A Topical Review on the Most Promising Craniomaxillofacial Applications

Bone regeneration in craniomaxillofacial surgery represents an issue that involves both surgical and aesthetic aspects. The most recent studies on bone tissue engineering involving adipose-derived stromal/stem cells (ASCs) have clearly demonstrated that such cells can play a crucial role in the treatment of craniomaxillofacial defects, given their strong commitment towards the osteogenic phenotype. A deeper knowledge of the molecular mechanisms underlying ASCs is crucial for a correct understanding of the potentialities of ASCs-based therapies in the most complex maxillofacial applications. In this topical review, we analyzed the molecular mechanisms of ASCs related to their support toward angiogenesis and osteogenesis, during bone regeneration. Moreover, we analyzed both case reports and clinical trials reporting the most promising clinical applications of ASCs in the treatment of craniomaxillofacial defects. Our study aimed to report the main molecular and clinical features shown by ASCs, used as a therapeutic support in bone engineering, as compared to the use of conventional autologous and allogeneic bone grafts.

Controlling stem cell behavior with decellularized extracellular matrix scaffolds

Decellularized tissues have become a common regenerative medicine platform with multiple materials being researched in academic laboratories, tested in animal studies, and used clinically. Ideally, when a tissue is decellularized the native cell niche is maintained with many of the structural and biochemical cues that naturally interact with the cells of that particular tissue. This makes decellularized tissue materials an excellent platform for providing cells with the signals needed to initiate and maintain differentiation into tissue-specific lineages. The extracellular matrix (ECM) that remains after the decellularization process contains the components of a tissue specific microenvironment that is not possible to create synthetically. The ECM of each tissue has a different composition and structure and therefore has unique properties and potential for affecting cell behavior. This review describes the common methods for preparing decellularized tissue materials and the effects that decellularized materials from different tissues have on cell phenotype.

Innovative approach for the in vitro research on biomedical scaffolds designed and customized with CAD-CAM technology

INTRODUCTION

Studies on biomaterials involve assays aimed to assess the interactions between the biomaterial and the cells seeded on its surface. However, the morphology of biomaterials is heterogeneous and it could be tricky to standardize the results among different biomaterials and the classic plastic plates. In this light, we decided to create, by means of computer-aided design (CAD) technology, a standardized sample model, with equal shape and sizes, able to fit into a classic shape of a 96-wells tissue culture plate (TCP).

METHODS

The design of this sample consists of a hole in the top in order to allow the injected cells to settle without them being able to slip from the sides of the sample to the bottom of the TCP wells. This CAD project is made using the software Pro-Engineer. The sample will totally fill the wells of the 96-well TCP. Dental pulp stem cells have been used to assess the ability of the different sample to support and promote the cell proliferation.

RESULTS

Twelve titanium, 12 gold-palladium, and 12 zirconium oxide customized samples were designed by means of the software cam powermill, by importing the .stl file created in Pro-Engineer software. The proliferation rate of the tested scaffolds showed to be similar to the control in the group with the customized shape.

CONCLUSION

We think that our method can be useful to test different types of scaffolds when a greater accuracy of the measurements is desirable in order to verify the cell behavior of these scaffolds. Our innovative method can improve the standardization process in the evaluation of cell behavior on different biomaterials to open the way to more reliable tests on biomatrices functionalized with drugs or growth factors applied to the future regenerative medicine.

Decellularized Human Skeletal Muscle as Biologic Scaffold for Reconstructive Surgery

Engineered skeletal muscle tissues have been proposed as potential solutions for volumetric muscle losses, and biologic scaffolds have been obtained by decellularization of animal skeletal muscles. The aim of the present work was to analyse the characteristics of a biologic scaffold obtained by decellularization of human skeletal muscles (also through comparison with rats and rabbits) and to evaluate its integration capability in a rabbit model with an abdominal wall defect. Rat, rabbit and human muscle samples were alternatively decellularized with two protocols: n.1, involving sodium deoxycholate and DNase I; n.2, trypsin-EDTA and Triton X-NH₄OH. Protocol 2 proved more effective, removing all cellular material and maintaining the three-dimensional networks of collagen and elastic fibers. Ultrastructural analyses with transmission and scanning electron microscopy confirmed the preservation of collagen, elastic fibres, glycosaminoglycans and proteoglycans. Implantation of human scaffolds in rabbits gave good results in terms of integration, although recellularization by muscle cells was not completely achieved. In conclusion, human skeletal muscles may be effectively decellularized to obtain scaffolds preserving the architecture of the extracellular matrix and showing mechanical properties suitable for implantation/integration. Further analyses will be necessary to verify the suitability of these scaffolds for in vitro recolonization by autologous cells before in vivo implantation.

Muscle extracellular matrix scaffold is a multipotent environment

The multipotency of scaffolds is a new concept. Skeletal muscle acellular scaffolds (MAS) implanted at the interface of Tibialis Anterior/tibial bone and masseter muscle/mandible bone in a murine model were colonized by muscle cells near the host muscle and by bone-cartilaginous tissues near the host bone, thus highlighting the importance of the environment in directing cell homing and differentiation. These results unveil the multipotency of MAS and point to the potential of this new technique as a valuable tool in musculo-skeletal tissue regeneration.