A novel hydrogel scaffold contained bioactive glass nanowhisker (BGnW) for osteogenic differentiation of human mesenchymal stem cells (hMSCs) in vitro

A photo-thermal dual crosslinked chitosan-based hydrogel membrane for guided bone regeneration

Alveolar bone defects caused by inflammation or trauma jeopardize patients' oral functions. Guided bone regeneration (GBR) is widely used in repairing periodontal tissue, with barrier membranes play a crucial role in preserving the bone regeneration space. In this study, an injectable dual-crosslinked hydrogel was developed to improve the existing barrier membranes in flexibility and functionality. The hydrogel matrix, composed of methacrylated carboxymethyl chitosan (CMCS) reinforced with robust silk fibroin (SF), was further functionalized with bioactive glass (BG) particles to promote bone regeneration. The pre-gel solution achieved a fast-curing process under visible light and at body temperature. Further, the composite hydrogels presented good biocompatibility, biodegradability, resilience, alongside in vitro barrier effect against human gingival fibroblasts (HGFs). It significantly enhanced osteogenic differentiation and angiogenesis of bone marrow mesenchymal stem cells (BMSCs), facilitate the tube formation of human umbilical vein endothelial cells (HUVECs), and inhibit Staphylococcus aureus and Porphyromonas gingivalis. In a rat skull defect model, the osteogenic performance of hydrogels was comparable with that of collagen membranes (Bio-Gide®). Overall, this in-situ gel-forming barrier material served as a stable carrier for bioactive ions and a biomineralized scaffold for tissue ingrowth, supporting the enhancement of GBR technique.

Osteogenic Differentiation of Adipose Tissue-Derived Mesenchymal Stem Cells on Composite Polymeric Scaffolds: A Review

The mesenchymal stem cells (MSCs) are the fundamental part of bone tissue engineering for the emergence of reconstructive medicine. Bone tissue engineering has recently been considered a promising strategy for treating bone diseases and disorders. The technique needs a scaffold to provide an environment for cell attachment to maintain cell function and a rich source of stem cells combined with appropriate growth factors. MSCs can be isolated from adipose tissue (ASCs), bone marrow (BM-MSCs), or umbilical cord (UC-MSCs). In the present study, the potential of ASCs to stimulate bone formation in composite polymeric scaffolds was discussed and it showed that ASCs have osteogenic ability in vitro. The results also indicated that the ASCs have the potential for rapid growth, easier adipose tissue harvesting with fewer donor site complications and high proliferative capacity. The osteogenic differentiation capacity of ASCs varies due to the culture medium and the addition of factors that can change signaling pathways to increase bone differentiation. Furthermore, gene expression analysis has a significant impact on improving our understanding of the molecular pathways involved in ASCs and, thus, osteogenic differentiation. Adding some drugs, such as dexamethasone, to the biomaterial composite also increases the formation of osteocytes. Combining ASCs with scaffolds synthesized from natural and synthetic polymers seems to be an effective strategy for bone regeneration. Applying exopolysaccharides, such as schizophyllan, chitosan, gelatin, and alginate in composite scaffolds enhances the osteogenesis potential of ASCs in bone tissue regeneration.

Investigating the indirect therapeutic effect of hAMSCs utilizing a novel scaffold (PGS-co-PCL/PGC/PPy/Gelatin) in myocardial ischemia-reperfusion-induced renal failure in male Wistar rats

BACKGROUND

Myocardial ischemia-reperfusion (MI/R) occurs due to temporary or permanent interruptions in the coronary and circulatory system, indirectly affecting kidney function through reduced cardiac output for metabolic needs. In this study, the aim was to explore the indirect effects of using human amniotic membrane mesenchymal stem cells (hAMSCs) with the PGS-co-PCL/PGC/PPy/Gelatin scaffold in male rats with renal failure induced by miocardial ischemia-reperfusion.

METHODS

MI/R injury was induced in 48 male Wistar rats through left anterior descending artery ligation, divided into four groups (n=12); control group, cell group, scaffold group, and celss+scaffold group. Evaluations were conducted at two and thirty days post MI/R injury, encompassing echocardiography, biochemical, inflammatory markers analysis, and histological assessment.

RESULTS

Echocardiographic findings exhibited notable enhancement in ejection fraction, fractional shortening, and stroke volume of treated groups compared to controls after 30 days (P< 0.05). Serum creatinine (P< 0.001) and urea (P< 0.05) levels significantly decreased in the scaffold+cells group) compared to the control group. The treated cells+ scaffold group displayed improved kidney structure, evidenced by larger glomeruli and reduced Bowman's space compared to the control group (P< 0.01). Immunohistochemical analysis indicated reduced TNF-α protein in the scaffold+ cells group (P< 0.05) in contrast to the control group (P< 0.05). Inflammatory factors IL-6, TNF-α, and AKT gene expression in renal tissues were improved in scaffold+ cells-treated animals.

CONCLUSION

Our research proposes the combination of hAMSCs and the PGS-co-PCL/PGC/PPy/Gelatin scaffold in MI/R injured rats appears to enhance renal function and reduce kidney inflammation by improving cardiac output.

Harnessing the potential of hydrogels for advanced therapeutic applications: current achievements and future directions

The applications of hydrogels have expanded significantly due to their versatile, highly tunable properties and breakthroughs in biomaterial technologies. In this review, we cover the major achievements and the potential of hydrogels in therapeutic applications, focusing primarily on two areas: emerging cell-based therapies and promising non-cell therapeutic modalities. Within the context of cell therapy, we discuss the capacity of hydrogels to overcome the existing translational challenges faced by mainstream cell therapy paradigms, provide a detailed discussion on the advantages and principal design considerations of hydrogels for boosting the efficacy of cell therapy, as well as list specific examples of their applications in different disease scenarios. We then explore the potential of hydrogels in drug delivery, physical intervention therapies, and other non-cell therapeutic areas (e.g., bioadhesives, artificial tissues, and biosensors), emphasizing their utility beyond mere delivery vehicles. Additionally, we complement our discussion on the latest progress and challenges in the clinical application of hydrogels and outline future research directions, particularly in terms of integration with advanced biomanufacturing technologies. This review aims to present a comprehensive view and critical insights into the design and selection of hydrogels for both cell therapy and non-cell therapies, tailored to meet the therapeutic requirements of diverse diseases and situations.

Recent advances in composite hydrogels: synthesis, classification, and application in the treatment of bone defects

Bone defects are often difficult to treat due to their complexity and specificity, and therefore pose a serious threat to human life and health. Currently, the clinical treatment of bone defects is mainly surgical. However, this treatment is often more harmful to patients and there is a potential risk of rejection and infection. Hydrogels have a unique three-dimensional structure that can accommodate a variety of materials, including particles, polymers and small molecules, making them ideal for treating bone defects. Therefore, emerging composite hydrogels are considered one of the most promising candidates for the treatment of bone defects. This review describes the use of different types of composite hydrogel in the treatment of bone defects. We present the basic concepts of hydrogels, different preparation techniques (including chemical and physical crosslinking), and the clinical requirements for hydrogels used to treat bone defects. In addition, a review of numerous promising designs of different types of hydrogel doped with different materials (e.g., nanoparticles, polymers, carbon materials, drugs, and active factors) is also highlighted. Finally, the current challenges and prospects of composite hydrogels for the treatment of bone defects are presented. This review will stimulate research efforts in this field and promote the application of new methods and innovative ideas in the clinical field of composite hydrogels.

Combined Application of Human Amniotic Membrane Mesenchymal Stem Cells and a Modified PGS-co-PCL Film in an Experimental Model of Myocardial Ischemia-Reperfusion Injury

According to the World Health Organization (WHO), about 3.9 million people die annually of ischemic heart disease (IHD). Several clinical trials have shown that stem cell therapy is a promising therapeutic approach to IHD. Human amniotic membrane mesenchymal stem cells (hAMSCs) positively affect the repair of myocardial ischemia-reperfusion (MI/R) injury by stimulating endogenous repair mechanisms. The differentiated hAMSCs with and without modified PGS-co-PCL film were applied in the myocardium. MI/R injury was induced by ligating the left anterior descending artery in 48 male Wistar rats. The rats were divided into four groups, (n = 12) animals: heart failure (HF) as the control group, HF + MSCs, HF + MSCs + film, and HF + film. Echocardiography was performed 2 and 4 weeks after MI/R injury moreover the expression of the VEGF protein was assessed in the rat heart tissue via immunohistochemistry. In vitro, our result shows fantastic cell survival when seeded on film. In vivo, the left ventricle ejection fraction (LEVD), fractional shortening (FS), end-diastolic (EDV), and stroke volume (SV) have been increased and systolic volumes decreased in all treatment groups in comparison with control. Although combination therapy has a more positive effect on hemodynamic parameters, there is no significant difference between HF + MSCs + film with other treatment groups. Also, In the IHC assay, expression of the VEGF protein significantly increased in all intervention groups. The implantation of MSCs and the modified film significantly enhanced the cardiac functional outcome; in this regard, enhancement in cell survival and VEGF expression are involved as underlying mechanisms in which cardiac film and MSCs exert a beneficial effect.

3D hydrogel/ bioactive glass scaffolds in bone tissue engineering: Status and future opportunities

Repairing significant bone defects remains a critical challenge, raising the clinical demand to design novel bone biomaterials that incorporate osteogenic and angiogenic properties to support the regeneration of vascularized bone. Bioactive glass scaffolds can stimulate angiogenesis and osteogenesis. In addition, natural or synthetic polymers exhibit structural similarity with extracellular matrix (ECM) components and have superior biocompatibility and biodegradability. Thus, there is a need to prepare composite scaffolds of hydrogels for vascularized bone, which incorporate to improve the mechanical properties and bioactivity of natural polymers. In addition, those composites' 3-dimensional (3D) form offer regenerative benefits such as direct doping of the scaffold with ions. This review presents a comprehensive discussion of composite scaffolds incorporated with BaG, focusing on their effects on osteo-inductivity and angiogenic properties. Moreover, the adaptation of the ion-doped hydrogel composite scaffold into a 3D scaffold for the generation of vascularized bone tissue is exposed. Finally, we highlight the challenges and future of manufacturing such biomaterials.

Design and characterization of adipose-derived mesenchymal stem cell loaded alginate/pullulan/hyaluronic acid hydrogel scaffold for wound healing applications

Recently, significant attention has been focused on the progression of skin equivalents to facilitate faster wound healing and thereby skin restoration. The main aim of this study was the design and characterization of a novel polysaccharide-based hydrogel scaffold by using alginate, pullulan, and hyaluronic acid polymers to provide an appropriate microenvironment to deliver Adipose-derived mesenchymal Stem Cells (ASC) in order to promote wound healing in an animal model. Characterization of synthesized hydrogel was done by using a field emission scanning electron microscope (FE-SEM), Fourier Transform-Infrared spectroscopy (FT-IR), and Differential Scanning Calorimetry (DSC). Also, contact angle analysis, the swelling and mechanical tests were performed. As a result of in vitro studies, cells can be attached, alive, and migrate through the prepared hydrogel scaffold. Finally, the therapeutic effect of the cell-seeded hydrogels was tested in the full-thickness animal wound model. Based on obtained results, the hydrogel-ASC treatment improved the healing process and accelerated wound closure.

Biocompatible scaffolds constructed by chondroitin sulfate microspheres conjugated 3D-printed frameworks for bone repair

Most bone repair scaffolds are multi-connected channel structure, but the hollow structure is not conducive to the transmission of active factors, cells and so on. Here, microspheres were covalently integrated into 3D-printed frameworks to form composite scaffolds for bone repair. The frameworks composed of double bond modified gelatin (Gel-MA) and nano-hydroxyapatite (nHAP) provided strong support for related cells climbing and growth. Microspheres, which were made of Gel-MA and chondroitin sulfate A (CSA), were able to connect the frameworks like bridges, providing channels for cells migration. Additionally, CSA released from microspheres promoted the migration of osteoblasts and enhanced osteogenesis. The composite scaffolds could effectively repair mouse skull defect and improve MC3T3-E1 osteogenic differentiation. These observations confirm the bridging effect of microspheres rich in chondroitin sulfate and also determine that the composite scaffold can be as a promising candidate for enhanced bone repair.

A new hydrogel with fluorapatite nanoparticles for osteogenic differentiation of human adipose-derived stem cells in tissue engineering field

Since scaffolds are engineered to support functional tissue formation, their design and materials play an essential role in medical fields by providing different mechanical function. The aim of this study was to investigate the synthesis and structural characterization of collagen-gelatin (COL-GEL) composite scaffolds containing fluorapatite (FA) nanoparticles as well as evaluation of the osteogenic differentiation of human adipose-derived stem cells (hADSCs). First, the composite scaffolds were evaluated using Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. The cytotoxicity of scaffolds and various concentrations of FA nanoparticles was studied through MTT assay and acridine orange/ethidium bromide staining. Next, the differentiated hADSCs were analyzed using Alizarin red and von Kossa staining, calcium content assay, alkaline phosphatase (ALP) activity, real-time RT-PCR, and immunocytochemical analyses. According to the characterization analyses, the composite scaffolds were properly integrated. The results also illustrated that COL-GEL composite scaffolds in the presence of FA nanoparticles not only showed no cytotoxicity but also increased ALP activity and calcium deposition as well as the expression of osteogenic genes, including Runx2, Col-I, ALP, and osteocalcin and the synthesis of proteins such as osteocalcin and osteopontin in vitro. The obtained data were confirmed by Alizarin red and von Kossa staining. These results are very promising for further tissue engineering experiments, in which FA nanoparticle incorporation into COL-GEL composite scaffolds is a novel approach that improves the surface COL-GEL composite scaffolds for tissue engineering application in vitro.