Regenerative Medicine Research Articles

Mesenchymal stem cells for repairing glaucomatous optic nerve

Glaucoma is a common and complex neurodegenerative disease characterized by progressive loss of retinal ganglion cells (RGCs) and axons. Currently, there is no effective method to address the cause of RGCs degeneration. However, studies on neuroprotective strategies for optic neuropathy have increased in recent years. Cell replacement and neuroprotection are major strategies for treating glaucoma and optic neuropathy. Regenerative medicine research into the repair of optic nerve damage using stem cells has received considerable attention. Stem cells possess the potential for multidirectional differentiation abilities and are capable of producing RGC-friendly microenvironments through paracrine effects. This article reviews a thorough researches of recent advances and approaches in stem cell repair of optic nerve injury, raising the controversies and unresolved issues surrounding the future of stem cells.

Advances in clinical applications of bioceramics in the new regenerative medicine era

In this editorial, we comment on the hard and soft tissue applications of different ceramic-based scaffolds prepared by different mechanisms such as 3D printing, sol-gel, and electrospinning. The new concept of regenerative medicine relies on biomaterials that can trigger in situ tissue regeneration and stem cell recruitment at the defect site. A large percentage of these biomaterials is ceramic-based as they provide the essential requirements of biomaterial principles such as tailored multisize porosity, antibacterial properties, and angiogenic properties. All these previously mentioned properties put bioceramics on top of the hierarchy of biomaterials utilized to stimulate tissue regeneration in soft and hard tissue wounds. Multiple clinical applications registered the use of these materials in triggering soft tissue regeneration in healthy and diabetic patients such as bioactive glass nanofibers. The results were promising and opened new frontiers for utilizing these materials on a larger scale. The same results were mentioned when using different forms and formulas of bioceramics in hard defect regeneration. Some bioceramics were used in combination with other polymers and biological scaffolds to improve their regenerative and mechanical properties. All this progress will enable a larger scale of patients to receive such services with ease and decrease the financial burden on the government.

Higher‐order Behaviours in Bio‐inspired Materials

Bio‐inspired approaches in materials science and systems chemistry are yielding a variety of stimuli‐responsive and dynamic materials that are gradually changing our everyday life. However, the ability to chemically program these materials to exhibit macroscopic higher‐order behaviours such as self‐assembly, contractility, swarming, taxis, chemical communication, or predator‐prey dynamics remains an ongoing challenge. While still in its infancy, the successful fabrication of bio‐inspired materials displaying higher‐order behaviours not only will help bridging the gap between living and non‐living matter, but it will also contribute to the development of advanced materials for potential applications ranging from tissue engineering and biotechnology, to soft robotics and regenerative medicine. Our Mini‐Review will systematically discuss the higher‐order behaviours developed thus far in bio‐inspired systems, namely (i) polymer networks (ii) microbots, (iii) protocells, and (iv) prototissues. For each system it will provide key examples and highlight how the emergent behaviour could be chemically programmed.

In Situ Labeling of the Aqueous Compartment of Extracellular Vesicles with Luminescent Gold Nanoclusters.

Extracellular vesicles (EVs) are well-known membrane-limited particles secreted by both healthy and cancerous cells. They are considered as biomarkers for early cancer diagnosis and are involved in many pathologies and physiological pathways. They could serve as diagnostic tools in liquid biopsies, as therapeutics in regenerative medicine, or as drug delivery vehicles. Our aim is here to encapsulate luminescent nanoprobes in the aqueous compartment of human EVs extracted from reproductive fluids. The analysis and labeling of the EVs content with easily detectable luminescent nanoparticles could enable a powerful tool for early diagnosis of specific diseases and also for the design of new therapeutics. In this view, gold nanoclusters (AuNCs) appear as an attractive alternative as nontoxic fluorophore probes because of their luminescence properties, large window of fluorescence lifetimes (1 ns-1 μs), ultrasmall size (<2 nm), good biocompatibility, and specific ability as X-ray photosensitizers. Here, we investigated an attractive method that uses fusogenic liposomes to deliver gold nanoclusters into EVs. This approach guarantees the preservation of the EVs membrane without any breakage, thus maintaining compartmental integrity. Different lipid compositions of liposomes preloaded with AuNCs were selected to interact electrostatically with human EVs and compared in terms of fusion efficiency. The mixture of liposomes and EVs results in membrane mixing as demonstrated by FRET experiments and fusion revealed by flux cytometry and cryo-TEM. The resulting fused EVs exhibit typical fluorescence of the AuNCs together with an increased size in agreement with fusion. Moreover, the fusion events in mixtures of EVs and AuNCs preloaded liposomes were analyzed by using cryo-electron microscopy. Finally, the ratio of released AuNCs during the fusion between the fusogenic liposomes and the EVs was estimated to be less than 20 mol % by Au titration using ICP spectroscopy.

Unraveling the Enigma of Organismal Death: Insights, Implications, and Frontiers.

Significant knowledge gaps exist regarding the responses of cells, tissues, and organs to organismal death. Examining the survival mechanisms influenced by metabolism and environment, this research has the potential to transform regenerative medicine, redefine legal death, and provide insights into life's physiological limits, paralleling inquiries in embryogenesis.

Exploring stem cell frontiers: definitions, challenges, and perspectives for regenerative medicine.

Each year, the European Summer School on Stem Cell Biology and Regenerative Medicine (SCSS) attracts early-career researchers and actively practicing clinicians who specialise in stem cell and regenerative biology. The 16th edition of this influential course took place from 12th to 19th September 2023 on the charming Greek island of Spetses. Focusing on important concepts and recent advances in stem cells, the distinguished faculty included experts spanning the spectrum from fundamental research to clinical trials to market-approved therapies. Alongside an academically intensive programme that bridges the various contexts of stem cell research, delegates were encouraged to critically address relevant questions in stem cell biology and medicine, including broader societal implications. Here, we present a comprehensive overview and key highlights from the SCSS 2023.

The platelet concentrates’ the hallmark in regeneration

Numerous studies have been done on the use of biocompatible materials in regenerative medicine. Platelet concentrates, also known as concentrated growth factor, platelet-rich fibrin, and platelet-rich plasma, are the result of centrifuging blood to separate out the platelets. Platelet concentrations have generated a great deal of discussion in both soft and hard tissue engineering. In fact, growth factors, fibrin matrix, and platelets are among the components of autologous platelet concentrate that are essential for the healing of wounds. Modern techniques for tissue restoration by increasing the properties of autologous platelet concentrates are the subject of current research. The usage of platelet concentrates and their role in tissue regeneration are addressed in the current study, along with a number of new advances and its biological effects.

Enhancing the Maturation of Human Pluripotent Stem Cell-Derived Cardiomyocytes with an n-Type Organic Semiconductor Coating.

Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) are a promising cell source for cardiac regenerative medicine and in vitro modeling. However, hPSC-CMs exhibit immature structural and functional properties compared with adult cardiomyocytes. Various electrical, mechanical, and biochemical cues have been applied to enhance hPSC-CM maturation but with limited success. In this work, we investigated the potential application of the semiconducting polymer poly{[N,N'-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)} (P(NDI2OD-T2)) as a light-sensitive material to stimulate hPSC-CMs optically. Our results indicated that P(NDI2OD-T2)-mediated photostimulation caused cell damage at irradiances applied long-term above 36 μW/mm2 and did not regulate cardiac monolayer beating (after maturation) at higher intensities applied in a transient fashion. However, we discovered that the cells grown on P(NDI2OD-T2)-coated substrates showed significantly enhanced expression of cardiomyocyte maturation markers in the absence of a light exposure stimulus. A combination of techniques, such as atomic force microscopy, scanning electron microscopy, and quartz crystal microbalance with dissipation monitoring, which we applied to investigate the interface of the cell with the n-type coating, revealed that P(NDI2OD-T2) impacted the nanostructure, adsorption, and viscoelasticity of the Matrigel coating used as a cell adhesion promoter matrix. This modified cellular microenvironment promoted the expression of cardiomyocyte maturation markers related to contraction, calcium handling, metabolism, and conduction. Overall, our findings demonstrate that conjugated polymers such as P(NDI2OD-T2) can be used as passive coatings to direct stem cell fate through interfacial engineering of cell growth substrates.

Reinforcing ethyl cellulose aerogels with poly(lactic acid) for enhanced bone regeneration

Abstract  Developing double porous biodegradable and biocompatible scaffolds that can incorporate and release drugs in a controlled manner holds immense potential in regenerative medicine. This study presents a synthesis method for preparing a macro-mesoporous scaffold, where poly(lactic acid) adds to the macroporous region and mechanical properties, and ethyl cellulose adds to the surface area (182 m2/g). High surface area enables the incorporation of model drug indomethacin with an entrapment efficiency of 17.0% and its later controlled release profile. The resulting scaffold has desirable mechanical properties in the range of a natural trabecular bone with a compressive modulus of 22.4 MPa. The material is stable in the simulated body fluids for 120 days before the slow degradation starts. In vitro studies demonstrate the material's ability to support bone cell adhesion, proliferation, and differentiation, promoting osteogenic activity. Overall, the unique combination of poly(lactic acid) and ethyl cellulose produces advanced materials with tailored macro and mesopore properties, remarkable mechanical properties, optimal degradation rate, and drug delivery potential, making it a promising candidate for bone scaffolds in regenerative medicine and tissue engineering.

The Combination of Bioactive Herbal Compounds with Biomaterials for Regenerative Medicine.

Regenerative medicine aims to restore the function of diseased or damaged tissues and organs by cell therapy, gene therapy, and tissue engineering, along with the adjunctive application of bioactive molecules. Traditional bioactive molecules, such as growth factors and cytokines, have shown great potential in the regulation of cellular and tissue behavior, but have the disadvantages of limited source, high cost, short half-life, and side effects. In recent years, herbal compounds extracted from natural plants/herbs have gained increasing attention. This is not only because herbal compounds are easily obtained, inexpensive, mostly safe, and reliable, but also owing to their excellent effects, including anti-inflammatory, antibacterial, antioxidative, proangiogenic behavior and ability to promote stem cell differentiation. Such effects also play important roles in the processes related to tissue regeneration. Furthermore, the moieties of the herbal compounds can form physical or chemical bonds with the scaffolds, which contributes to improved mechanical strength and stability of the scaffolds. Thus, the incorporation of herbal compounds as bioactive molecules in biomaterials is a promising direction for future regenerative medicine applications. Herein, an overview on the use of bioactive herbal compounds combined with different biomaterial scaffolds for regenerative medicine application is presented. We first introduce the classification, structures, and properties of different herbal bioactive components and then provide a comprehensive survey on the use of bioactive herbal compounds to engineer scaffolds for tissue repair/regeneration of skin, cartilage, bone, neural, and heart tissues. Finally, we highlight the challenges and prospects for the future development of herbal scaffolds toward clinical translation. Overall, it is believed that the combination of bioactive herbal compounds with biomaterials could be a promising perspective for the next generation of regenerative medicine.

Two‐Way Regulation of MgFe‐LDH on ESC Cell Fate via Temporal Selective Activation of Different Cell Membrane Receptors

AbstractStem cell fate regulation by biomaterials has considerable therapeutic potential; however, the mechanisms whereby biomaterials instruct stem cells for accurate fate regulation still need to be elucidated. Layered double hydroxide (LDH) nanoparticles are widely used for tissue regeneration because of their excellent physicochemical properties and biocompatibility. This study reveals that MgFe‐LDH has bidirectional regulatory effects on the differentiation of mouse embryonic stem cells into neural progenitor cells, essentially suppressing cell differentiation on the 1st day and promoting cell differentiation on the 3rd day. Single‐cell transcriptome sequencing and simulated computation of structural analysis demonstrate that MgFe‐LDH interacts with the membrane receptors leukemia inhibitory factor receptor (LIFR, 15 nm above the cell membrane) and pached1 (PTCH1, 6 nm above the cell membrane) on the 1st and 3rd day of differentiation, respectively. LIFR has more contact with MgFe‐LDH than PTCH1 and relatively weaker electrostatic interaction energies (−11010.0 and −9829.3 kJ mol−1 for PTCH1 and LIFR, respectively). These factors determine receptor binding and activation priority, followed by cell fate regulation. The results indicate that MgFe‐LDH regulate the activity and fate of stem cells dually, thus creating possibilities for personalized therapy in neurodevelopment and regenerative medicine through an in‐depth study of cell membrane receptors.

Powerful Protein Nanoreservoirs Based on Stellate Mesoporous Silica Embedded in Composite Hydrogels: From Burst Release to Retention

AbstractIn the biomaterials field, one major issue with hydrogels (HGs) loaded with active therapeutics is the spontaneous leaking of the cargo occurring rapidly, usually over several hours. However, biological processes involved in regenerative medicine would require to have a sustained drug delivery lasting over weeks/months or be triggered only when a specific biochemical stimulus (enzymatic, cellular, or antimicrobial) is applied. In this work, this challenge is addressed by demonstrating that the spontaneous protein release from an agarose HG (used as model HG) can be partially or totally blocked by the incorporation of stellate mesoporous silica (STMS) nanoparticles (NPs, ≈150 ± 28 nm size, 15 nm pore) within the HG. It is shown here that the porous silica NPs act as sub‐micrometer size reservoirs ensuring precise level retention simply by playing on the amount of STMS embedded in the HG. Further, this effect is shown for various proteins demonstrating the versatility of this concept.

Nasal septum-derived chondroprogenitor cells control mandibular condylar resorption consequent to orthognathic surgery: a clinical trial.

Condylar resorption is an aggressive and disability form of temporomandibular joint (TMJ) degenerative disease, usually non-respondent to conservative or minimally invasive therapies and often leading to surgical intervention and prostheses implantation. This condition is also one of the most dreaded postoperative complications of orthognathic surgery, with severe cartilage erosion and loss of subchondral bone volume and mineral density, associated with a painful or not inflammatory processes. Because regenerative medicine has emerged as an alternative for orthopedic cases with advanced degenerative joint disease, we conducted a phase I/IIa clinical trial (U1111-1194-6997) to evaluate the safety and efficacy of autologous nasal septal chondroprogenitor cells. Ten participants underwent biopsy of the nasal septum cartilage during their orthognathic surgery. The harvested cells were cultured in vitro and analyzed for viability, presence of phenotype markers for mesenchymal stem and/or chondroprogenitor cells, and the potential to differentiate into chondrocytes, adipocytes, and osteoblasts. After the intra-articular injection of the cell therapy, clinical follow-up was performed using the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) and computed tomography (CT) images. No serious adverse events related to the cell therapy injection were observed during the 12-month follow-up period. It was found that autologous chondroprogenitors reduced arthralgia, promoted stabilization of mandibular function and condylar volume, and regeneration of condylar tissues. This study demonstrates that chondroprogenitor cells from the nasal septum may be a promise strategy for the treatment of temporomandibular degenerative joint disease that do not respond to other conservative therapies.

Advanced Smart Biomaterials for Regenerative Medicine and Drug Delivery Based on Phosphoramidite Chemistry: From Oligonucleotides to Precision Polymers.

Over decades of development, while phosphoramidite chemistry has been known as the leading method in commercial synthesis of oligonucleotides, it has also revolutionized the fabrication of sequence-defined polymers (SDPs), offering novel functional materials in polymer science and clinical medicine. This review has introduced the evolution of phosphoramidite chemistry, emphasizing its development from the synthesis of oligonucleotides to the creation of universal SDPs, which have unlocked the potential for designing programmable smart biomaterials with applications in diverse areas including data storage, regenerative medicine and drug delivery. The key methodologies, functions, biomedical applications, and future challenges in SDPs, have also been summarized in this review, underscoring the significance of breakthroughs in precisely synthesized materials.

Bioprinting of a Liposomal Oxygen-Releasing Scaffold for Ovary Tissue Engineering.

This study addresses a critical challenge in bioprinting for regenerative medicine, specifically the issue of hypoxia compromising cell viability in engineered tissues. To overcome this hurdle, a novel approach using a microfluidic bioprinter is used to create a two-layer structure resembling the human ovary. This structure incorporates a liposomal oxygen-releasing system to enhance cell viability. The bioprinting technique enables the simultaneous extrusion of two distinct bioinks, namely, bioink A (comprising alginate 1% and 5 mg/mL PEGylated fibrinogen in a 20:1 molar ratio) and bioink B (containing alginate 0.5%). In addition, liposomal catalase and hydrogen peroxide (H2O2) are synthesized and incorporated into bioinks A and B, respectively. The liposomes are prepared using thin film hydration with a monodisperse size (140-160 nm) and high encapsulation efficiency. To assess construct functionality, isolated human ovarian cells are added to bioink A. The bioprinted constructs, with or without liposomal oxygen-releasing systems, are cultured under hypoxic and normoxic conditions for 3 days. Live/Dead assay results demonstrate that liposomal oxygen-releasing systems effectively preserve cell viability in hypoxic conditions, resembling viability under normoxic conditions without liposomes. PrestoBlue assay reveals significantly higher mitochondrial activity in constructs with liposomal oxygen delivery systems under both hypoxic and normoxic conditions. The evaluation of apoptosis status through annexin V immunostaining shows that liposomal oxygen-releasing scaffolds successfully protect cells from hypoxic stress, exhibiting a proportion of apoptotic cells similar to normoxic conditions. In contrast, constructs lacking liposomes in hypoxic conditions exhibit a higher incidence of cells in early-stage apoptosis. In conclusion, the study demonstrates the promising potential of bioprinted oxygen-releasing liposomal scaffolds to protect ovarian stromal cells in hypoxic environments. These innovative scaffolds not only offer protection but also recapitulate the mechanical differences between the medulla and the cortex in the normal ovary structure. This opens new avenues for advanced ovary tissue engineering and transplantation strategies.

The role of health surveillance in the face of self-medication in the context of Covid-19: A literature reviewha

The politicization of the disease led to misinformation and the use of unproven treatments, such as the “COVID Kit”. The National Health Surveillance Agency (ANVISA) took important measures, including management and planning, health risk control, regulation, monitoring of suspected and confirmed cases, as well as information, communication and health education. Therefore, the general objective of this research is to demonstrate how the National Health Surveillance Agency (ANVISA) acted in the face of self-medication in the context of COVID-19. To this end, a literature review was carried out over the last five years on self-medication, pandemics, health surveillance, using databases such as PubMed, Google Scholar, Scientific Electronic Library Online (SciELO), Manuals from the Ministry of Health and the World Health Organization Inclusion criteria were adopted, such as articles published in Portuguese or English, primary studies and literature reviews, while studies that did not meet the general objective of the work and publications prior to 2019 were excluded. Regarding the results, ANVISA played an important role in the control and regulation of medicines during the pandemic, classifying chloroquine as a special control medicine and carrying out more than 30 thousand inspections to ensure compliance with clinical protocols to combat the disease. Finally, the pandemic brought challenges for health surveillance professionals, in order to contain the spread of the coronavirus, especially regarding the inappropriate use of medicines and other products subject to health assessment.

Mesenchymal stem cells derived-exosomes enhanced amniotic membrane extract promotes corneal keratocyte proliferation.

Amniotic membrane extract (AME) and Wharton's jelly mesenchymal stem cells derived-exosomes (WJ-MSC-Exos) are promising therapeutic solutions explored for their potential in tissue engineering and regenerative medicine, particularly in skin and corneal wound healing applications. AME is an extract form of human amniotic membrane and known to contain a plethora of cytokines and growth factors, making it a highly attractive option for topical applications. Similarly, WJ-MSC-Exos have garnered significant interest for their wound healing properties. Although WJ-MSC-Exos and AME have been used separately for wound healing research, their combined synergistic effects have not been studied extensively. In this study, we evaluated the effects of both AME and WJ-MSC-Exos, individually and together, on the proliferation of corneal keratocytes as well as their ability to promote in vitro cell migration, wound healing, and their impact on cellular morphology. Our findings indicated that the presence of both exosomes (3 × 105 Exo/mL) and AME (50 μg/mL) synergistically enhance the proliferation of corneal keratocytes. Combined use of these solutions (3 × 105 Exo/mL + 50 μg/mL) increased cell proliferation compared to only 50 μg/mL AME treatment on day 3 (**** p < 0.0001). This mixture treatment (3 × 105 Exo/mL + 50 μg/mL) increased wound closure rate compared to isolated WJ-MSC-Exo treatment (3 × 105 Exo/mL) (*p < 0.05). Overall, corneal keratocytes treated with AME and WJ-MSC-Exo (3 × 105 Exo/mL + 50 μg/mL) mixture resulted in enhanced proliferation and wound healing tendency. Utilization of combined use of AME and WJ-MSC-Exo can pave the way for a promising foundation for corneal repair research.

Bioactive scaffolds for tissue engineering: A review of decellularized extracellular matrix applications and innovations

AbstractDecellularized extracellular matrix (dECM) offers a three‐dimensional, non‐immunogenic scaffold, enriched with bioactive components, making it a suitable candidate for tissue regeneration. Although dECM‐based scaffolds have been successfully implemented in preclinical and clinical settings within tissue engineering and regenerative medicine, the mechanisms of tissue remodeling and functional restoration are not fully understood. This review critically assesses the state‐of‐the‐art in dECM scaffolds, including decellularization techniques for various tissues, quality control and cross‐linking. It highlights the functional properties of dECM components and their latest applications in multiorgan tissue engineering and biomedicine. Additionally, the review addresses current challenges and limitations of decellularized scaffolds and offers perspectives on future directions in the field.

Horizons in Endometriosis: Proceedings of the Montreux Reproductive Summit, 14-15 July 2023.

Endometriosis is a complex and chronic gynaecological disorder that affects millions of women worldwide, leading to significant morbidity and impacting reproductive health. This condition affects up to 10% of women of reproductive age and is characterised by the presence of endometrial-like tissue outside the uterus, potentially leading to symptoms such as chronic pelvic pain, dysmenorrhoea, dyspareunia, and infertility. The Montreux summit brought a number of experts in this field together to provide a platform for discussion and exchange of ideas. These proceedings summarise the six main topics that were discussed at this summit to shed light on future directions of endometriosis classification, diagnosis, and therapeutical management. The first question addressed the possibility of preventing endometriosis in the future by identifying risk factors, genetic predispositions, and further understanding of the pathophysiology of the condition to develop targeted interventions. The clinical presentation of endometriosis is varied, and the correlation between symptoms severity and disease extent is unclear. While there is currently no universally accepted optimal classification system for endometriosis, several attempts striving towards its optimisation - each with its own advantages and limitations - were discussed. The ideal classification should be able to reconcile disease status based on the various diagnostic tools, and prognosis to guide proper patient tailored management. Regarding diagnosis, we focused on future tools and critically discussed emerging approaches aimed at reducing diagnostic delay. Preserving fertility in endometriosis patients was another debatable aspect of management that was reviewed. Moreover, besides current treatment modalities, potential novel medical therapies that can target underlying mechanisms, provide effective symptom relief, and minimise side effects in endometriotic patients were considered, including hormonal therapies, immunomodulation, and regenerative medicine. Finally, the question of hormonal substitution therapy after radical treatment for endometriosis was debated, weighing the benefits of hormone replacement.

Clinical results in patients affected by moderate-severe knee osteoarthritis and treated with micro-fragmented adipose tissue: the therapeutic effects on symptomatology.

Osteoarthrosis is a degenerative musculoskeletal disease that presents a major public health problem, due to the increasing average age of the active population, as well as the increasing percentage of obesity or overweight of the general population. New therapeutic approaches have been developed, such as regenerative medicine that uses mesenchymal stromal cells taken from adipose tissue. This study analyzed the clinical potential benefits of using autologous adipose tissue to treat patients with moderate-severe knee osteoarthritis.In 2021, a total of 50 knees, affected by moderate-severe knee osteoarthritis, were treated with an intra-articular injection of micro-fragmented subcutaneous adipose tissue. Patients were submitted to the KOOS questionnaire before the operation and one year after the operation and VAS pain score at time 0, 3, 6, 12 months.Of the 50 patients treated, 2 patients were excluded from the study. Of the remaining 48 patients, improvements have been achieved in all subclasses of KOOS. In particular, VAS score proves that improvements are more considerable starting from the 3rd month after surgery.The results obtained in this study show the safety and potential benefit of the use of autologous micro-fragmented adipose on people who are affected by moderate-severe knee osteoarthritis.