Local delivery of platelet-derived factors mitigates ischemia and preserves ovarian function through angiogenic modulation: A personalized regenerative strategy for fertility preservation.

As the most prominent and ideal modality in female fertility preservation, ovarian tissue cryopreservation, and transplantation often confront the challenge of ischemic damage and follicular loss from avascular transplantation. To surmount this impediment, we engineered a novel platelet-derived factors-encapsulated fibrin hydrogel (PFH), a paradigmatic biomaterial. PFH encapsulates autologous platelet-derived factors, utilizing the physiological blood coagulation cascade for precise local delivery of bioactive molecules. In our study, PFH markedly bolstered the success of avascular ovarian tissue transplantation. Notably, the quantity and quality of follicles were preserved with improved neovascularization, accompanied by decreased DNA damage, increased ovulation, and superior embryonic development rates under a Low-concentration Platelet-rich plasma-derived factors encapsulated fibrin hydrogel (L-PFH) regimen. At a stabilized point of tissue engraftment, gene expression analysis mirrored normal ovarian tissue profiles, underscoring the effectiveness of L-PFH in mitigating the initial ischemic insult. This autologous blood-derived biomaterial, inspired by nature, capitalizes on the blood coagulation cascade, and combines biodegradability, biocompatibility, safety, and cost-effectiveness. The adjustable properties of this biomaterial, even in injectable form, extend its potential applications into the broader realm of personalized regenerative medicine. PFH emerges as a promising strategy to counter ischemic damage in tissue transplantation, signifying a broader therapeutic prospect. (197 words).

Mitochondrial 'Birth-Death' coordinator: An intelligent hydrogen nanogenerator to enhance intervertebral disc regeneration.

Currently, mitochondrial dysfunction caused by oxidative stress is a growing concern in degenerative diseases, notably intervertebral disc degeneration (IVDD). Dysregulation of the balance of mitochondrial quality control (MQC) has been considered the key contributor, while it's still challenging to effectively harmonize different MQC components in a simple and biologically safe way. Hydrogen gas (H2) is a promising mitochondrial therapeutic molecule due to its bio-reductivity and diffusibility across cellular membranes, yet its relationship with MQC regulation remains unknown. Herein, we propose a mitochondrial 'Birth-Death' coordinator achieved by an intelligent hydrogen nanogenerator (Fe@HP-OD), which can sustainably release H2 in response to the unique microenvironment in degenerated IVDs. Both in vitro and in vivo results prove alleviation of cellular oxidative stress and restoration of nucleus pulposus cells function, thereby facilitating successful IVD regeneration. Significantly, this study for the first time proposes the mitochondrial 'Birth-Death' coordination mechanism: 1) attenuation of overactivated mitochondrial 'Death' process (UPRmt and unselective mitophagy); and 2) activation of Adenosine 5'-monophosphate-activated protein kinase (AMPK) signaling pathway for mitochondrial 'Birth-Death' balance (mitochondrial biogenesis and controlled mitophagy). These pioneering findings can fill in the gaps in molecular mechanisms for H2 regulation on MQC homeostasis, and pave the way for future strategies towards restoring equilibrium of MQC system against degenerative diseases.

Magnetically induced anisotropic structure in an injectable hydrogel for skeletal muscle regeneration.

Skeletal muscle integrity and its intrinsic aligned architecture are crucial for locomotion, postural support, and respiration functions, impacting overall quality of life. However, volumetric muscle loss (VML) can exceed intrinsic regenerative potential, leading to fibrosis and impairments. Autologous muscle grafting, the current gold standard, is constrained by tissue availability and success rates. Therefore, innovative strategies like cell-based therapies and scaffold-based approaches are needed. Our minimally invasive approach involves a tunable injectable hydrogel capable of achieving an aligned architecture post-injection via a low-intensity static magnetic field (SMF). Our hydrogel formulation uses gellan gum as the backbone polymer, enriched with essential extracellular matrix components such as hyaluronic acid and collagen type I, enhancing bio-functionality. To achieve an aligned architectural biomimicry, collagen type I is coupled with iron oxide magnetic nanoparticles, creating magnetic collagen bundles (MagC) that align within the hydrogel when exposed to a SMF. An extensive study was performed to characterize MagC and assess the hydrogel's stability, mechanical properties, and biological response in vitro and in vivo. The proposed system, fully composed of natural polymers, exhibited mechanical properties similar to human skeletal muscle and demonstrated effective biological performances, supporting its potential as a safe and patient-friendly treatment for VML.

Decellularized Extracellular Matrix Scaffolds: Recent Advances and Emerging Strategies in Bone Tissue Engineering.

Bone tissue engineering (BTE) is a complex biological process involving the repair of bone tissue with proper neuronal network and vasculature as well as bone surrounding soft tissue. Synthetic biomaterials used for BTE should be biocompatible, support bone tissue regeneration, and eventually be degraded in situ and replaced with the newly generated bone tissue. Recently, various forms of bone graft materials such as hydrogel, nanofiber scaffolds, and 3D printed composite scaffolds have been developed for BTE application. Decellularized extracellular matrix (DECM), a kind of natural biological material obtained from specific tissues and organs, has certain advantages over synthetic and exogenous biomaterial-derived bone grafts. Moreover, DECM can be developed from a wide range of biological sources and possesses strong molding abilities, natural 3D structures, and bioactive factors. Although DECM has shown robust osteogenic, proangiogenic, immunomodulatory, and bone defect healing potential, the rapid degradation and limited mechanical properties should be improved for bench-to-bed translation in BTE. This review summarizes the recent advances in DECM-based BTE and discusses emerging strategies of DECM-based BTE.

Industry updates from the field of stem cell research and regenerative medicine in August 2024.

Latest developments in the field of stem cell research and regenerative medicine compiled from publicly available information and press releases from non-academic institutions in August 2024.

Dentin Grafts: Navigating the Paradigm Shift in Regenerative Dentistry.

The biomaterial of dentin has emerged as a promising candidate for the tissue engineering of dental hard tissues. In bone tissue engineering, it may serve as either a scaffold or a reservoir of growth factors. The physical and chemical similarities between the dentin structure and bone have sparked scientific interest in using its features for the development of a new bone transplant material. Dentin, unlike hard and fragile enamel, is viscoelastic, making it a very effective bone replacement. The regeneration of pulp tissue has proven challenging due to its encasement in dentin, which lacks collateral blood flow except from the apical end of the root. Yet, the emergence of contemporary tissue engineering and the identification of dental stem cells have enabled experimentation with the regeneration of both pulp and dentin. This review will explain the different types of dentin grafts, their biocompatibility, safety, and effectiveness, along with difficulties. Additionally, the paper covers several strategies for creating autogenous dentin grafts and gives evidence-based insights into their clinical effectiveness. Overall, dentin grafts appear as a potential alternative to standard graft materials, stimulating tissue regeneration and enhancing patient outcomes in regenerative dentistry operations.

Emergence of the stromal vascular fraction and secretome in regenerative medicine.

Recently, we read a mini-review published by Jeyaraman et al. The article explored the optimal methods for isolating mesenchymal stromal cells from adipose tissue-derived stromal vascular fraction (SVF). Key factors include tissue source, processing techniques, cell viability assessment, and the advantages/disadvantages of autologous vs allogeneic use. The authors emphasized the need for standardized protocols for SVF isolation, ethical and regulatory standards for cell-based therapy, and safety to advance mesenchymal stromal cell-based therapies in human patients. This manuscript shares our perspective on SVF isolation in canines. We discussed future directions to potentiate effective regenerative medicine therapeutics in human and veterinary medicine.

Advancing diabetes management: Exploring pancreatic beta-cell restoration's potential and challenges.

Diabetes mellitus, characterized by chronic hyperglycemia due to insulin deficiency or resistance, poses a significant global health burden. Central to its pathogenesis is the dysfunction or loss of pancreatic beta cells, which are res-ponsible for insulin production. Recent advances in beta-cell regeneration research offer promising strategies for diabetes treatment, aiming to restore endogenous insulin production and achieve glycemic control. This review explores the physiological basis of beta-cell function, recent scientific advan-cements, and the challenges in translating these findings into clinical applications. It highlights key developments in stem cell therapy, gene editing technologies, and the identification of novel regenerative molecules. Despite the potential, the field faces hurdles such as ensuring the safety and long-term efficacy of regen-erative therapies, ethical concerns around stem cell use, and the complexity of beta-cell differentiation and integration. The review highlights the importance of interdisciplinary collaboration, increased funding, the need for patient-centered approaches and the integration of new treatments into comprehensive care strategies to overcome these challenges. Through continued research and collaboration, beta-cell regeneration holds the potential to revolutionize diabetes care, turning a chronic condition into a manageable or even curable disease.

Caspases promote cell proliferation after necrosis.

An enzyme known as caspase, which initiates apoptosis, has a central role in the regeneration of cells and repair of tissue that can occur after necrosis.

Industry updates from the field of stem cell research and regenerative medicine in July 2024.

Latest developments in the field of stem cell research and regenerative medicine compiled from publicly available information and press releases from non-academic institutions in July 2024.

Magnetic Resonance Imaging appearance of regenerative peripheral nerve interface.

PURPOSE: To describe the MRI appearance of regenerative peripheral nerve interface (RPNI) and the potential association between the MRI appearance and RPNI revision. MATERIAL AND METHODS: A retrospective assessment was undertaken of the MRI appearance of RPNIs performed at our institution between 1/1/2010 and 7/29/2023 with clinical correlation. RESULTS: Fourteen patients (8 men and 6 women, age range 31-80 years, median age 51 years) with technically adequate MRI of RPNIs were included in this study including 5 patients with below knee amputation with 5 tibial and 4 common peroneal nerves RPNI, 8 patients with above knee amputations (AKA) with sciatic RPNIs, and 1 patient following forequarter amputation with a brachial plexus RPNI. Two patients underwent revision RPNI surgery thrice (AKA-sciatic nerve) for a total of 6 RPNI revisions. On T1 weighted sequences, all RPNIs were isointense to the muscle and blended with the surrounding scar and muscle tissues whereas on T2 weighted sequences, all RPNIs were hyperintense in signal compared to the muscle. All but 1 RPNI underwent post contrast enhancement in variable patterns. No statistically significant difference in MRI appearance was found between RPNIs with or without a following RPNI revision surgery. CONCLUSION: RPNI on MRI typically have a bright and intermediate signal on T2 and T1 weighted sequences, respectively, and typically undergo postcontrast enhancement in variable patterns without a statistically significant difference between the cases with and without follow-up RPNI revision. However, enhancement of RPNI should not be misconstrued as pathological.

Transplantation of human pluripotent stem cell-derived retinal sheet in a primate model of macular hole.

Macular hole (MH) is a retinal break involving the fovea that causes impaired vision. Although advances in vitreoretinal surgical techniques achieve >90% MH closure rate, refractory cases still exist. For such cases, autologous retinal transplantation is an optional therapy showing good anatomic success, but visual improvement is limited and peripheral visual field defects are inevitable after graft harvesting. Here, using a non-human primate model, we evaluated whether human embryonic stem cell-derived retinal organoid (RO) sheet transplantation can be an effective option for treating MH. After transplantation, MH was successfully closed by continuous filling of the MH space with the RO sheet, resulting in improved visual function, although no host-graft synaptic connections were confirmed. Mild xeno-transplantation rejection was controlled by additional focal steroid injections and rod/cone photoreceptors developed in the graft. Overall, our findings suggest pluripotent stem cell-derived RO sheet transplantation as a practical option for refractory MH treatment.

Advanced therapy with mesenchymal stromal cells for knee osteoarthritis: Systematic review and meta-analysis of randomized controlled trials.

Background: Advanced cell therapies emerged as promising candidates for treatment of knee articular diseases, but robust evidence regarding their clinical applicability is still lacking. Objective: To assess the efficacy and safety of advanced mesenchymal stromal cells (MSC) therapy for knee osteoarthritis (OA) and chondral lesions. Methods: Systematic review of randomized controlled trials conducted in accordance with Cochrane Handbook and reported following PRISMA checklist. GRADE approach was used for assessing the evidence certainty. Results: 25 randomized controlled trials that enrolled 1048 participants were included. Meta-analyses data showed that, compared to viscosupplementation (VS), advanced MSC therapy resulted in a 1.91 lower pain VAS score (95 % CI -3.23 to -0.59; p < 0.00001) for the treatment of knee OA after 12 months. Compared to placebo, the difference was 0.99 lower pain VAS points (95 % CI -1.94 to -0.03; p = 0.76). According to the GRADE approach, the evidence was very uncertain for both comparisons. By excluding studies with high risk of bias, there was a similar size of effect (VAS MD -1.54, 95 % CI -2.09 to -0.98; p = 0.70) with improved (moderate) certainty of evidence, suggesting that MSC therapy probably reduces pain slightly better than VS. Regarding serious adverse events, there was no difference from advanced MSC therapy to placebo or to VS, with very uncertain evidence. Conclusion: Advanced MSC therapy resulted in lower pain compared to placebo or VS for the treatment of knee OA after 12 months, with no difference in adverse events. However, the evidence was considered uncertain. The Translational Potential of this Article: Currently, there is a lack of studies with good methodological structure aiming to evaluate the real clinical impact of advanced cell therapy for knee OA. The present study was well structured and conducted, with Risk of Bias, GRADE certainty assessment and sensitivity analysis. It explores the translational aspect of the benefits and safety of MSC compared with placebo and gold-standard therapy to give practitioners and researchers support to expand this therapy in their practice. PROSPERO registration number: CRD42020158173. Access at https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=158173.

Comparative Evaluation of Platelet-rich Fibrin and Treated Dentin Matrix in Regenerative Endodontic Treatment of Nonvital Immature Permanent Teeth: A Randomized Clinical Trial.

AIM: Clinical and radiographic evaluation of the efficacy of platelet-rich fibrin (PRF) and treated dentin matrix (TDM) in regenerative endodontic treatment and periapical healing of nonvital immature permanent teeth with chronic apical periodontitis. MATERIALS AND METHODS: Twenty-four children aged between 7 and 11 years, each presenting with a nonvital immature permanent upper central incisor, were selected. They were randomly allocated into two groups (n = 12), group I (PRF) and group II (TDM). Baseline clinical findings were recorded, and preoperative cone-beam computed tomography (CBCT) was taken. Follow-up was done clinically for 15 months at 3-month intervals (3, 6, 9, 12, and 15 months), and CBCT was taken at the end of the 15-month follow-up. Root length, apical diameter, radiographic root area (RRA), and size of the periapical lesion were quantitively assessed at the end of follow-up period and compared to the preoperative CBCT. RESULTS: Clinical success was 100% in both groups by the end of the follow-up period. Radiographically, after a 15-month follow-up, there was a significant increase in root length and RRA, and there was also a significant reduction in apical diameter and lesion size within each group (p < 0.05). However, there was no statistically significant difference between both groups regarding the mean percentage of increase in root length and mean percentage of reduction of apical diameter (p > 0.05). On the other hand, PRF showed more increase in RRA and more reduction in lesion size, with a statistically significant difference between both groups (p < 0.05). CONCLUSION: Both PRF and TDM were clinically successful. Platelet-rich fibrin showed better radiographic outcomes and periapical healing. CLINICAL SIGNIFICANCE: Platelet-rich fibrin is a viable scaffold to aid further root development and resolution of periapical lesions of nonvital immature permanent teeth. Further studies with different forms of TDM are needed to assess the efficacy of TDM in regenerative endodontic treatment of nonvital immature permanent teeth. How to cite this article: Asal MA, Elkalla IH, Awad SM, et al. Comparative Evaluation of Platelet-rich Fibrin and Treated Dentin Matrix in Regenerative Endodontic Treatment of Nonvital Immature Permanent Teeth: A Randomized Clinical Trial. J Contemp Dent Pract 2024;25(6):563-574.

Effects of human amniotic membrane on the angiogenesis and healing of ischemic wounds in a rat model.

Although the human amniotic membrane (hAM) has been demonstrated to promote angiogenesis, its efficacy in healing ischemic wounds remains unknown. Therefore, the current study aimed to evaluate the potential of hAM as a dressing for treating ischemic wounds. The inferior abdominal wall arteries and veins of male rats were divided, and an ischemic wound was created on each side of the abdominal wall. Of the two ischemic wounds created, only one was covered with hAM, and its wound healing effect was determined by measuring the wound area. Angiogenesis was assessed by measuring microvessel density (MVD). On day 5, the mean wound area changed from 400 mm2 to 335.4 (260-450) mm2 in the hAM group and to 459 (306-570) mm2 in the control group (p = 0.0051). MVD was 19.0 (10.4-24.6) in the hAM group and 15.1 (10.6-20.8) in the control group (p = 0.0026). No significant differences in local pro- and anti-inflammatory cytokine levels were observed between the two groups. Histological examination revealed no rejection of the transplanted hAM. Therefore, the hAM may serve as a novel wound dressing that can promote angiogenesis and healing in ischemic wounds.

Efficacy of a Single Injection of Stromal Vascular Fraction in Dogs with Elbow Osteoarthritis: A Clinical Prospective Study.

This study aimed to assess the efficacy of a single intra-articular injection of autologous stromal vascular fraction (SVF) in dogs with chronic lameness due to advanced elbow osteoarthritis (OA) that were unresponsive to conventional drug therapy. In this clinical, prospective, non-blinded, single-center study, twenty-three dogs received autologous SVF derived from falciform adipose tissue. Primary outcome measures over the six-month study period included clinical-orthopedic and radiographic examinations, objective gait analysis and validated owner questionnaires. In 19 of 23 joints, no progression of OA was visible radiographically. Peak vertical force improved significantly at three months and vertical impulse at six months after the injection compared to baseline. Over 33% of dogs demonstrated treatment-related improvements in lameness based on objective gait analysis. Owner questionnaires indicated significant improvement in clinical signs throughout the study period and 26% of dogs showed treatment-related improvements in pain scores according to the Canine Brief Pain Inventory. No side effects were reported. These findings suggest that autologous regenerative cell therapy may provide a promising treatment option for dogs with advanced OA that do not respond to conventional drug therapy. However, the treatment did not improve the clinical symptoms in all dogs, so it cannot be recommended for all patients.

Connexin 43 regulates intercellular mitochondrial transfer from human mesenchymal stromal cells to chondrocytes.

BACKGROUND: The phenomenon of intercellular mitochondrial transfer from mesenchymal stromal cells (MSCs) has shown promise for improving tissue healing after injury and has potential for treating degenerative diseases like osteoarthritis (OA). Recently MSC to chondrocyte mitochondrial transfer has been documented, but the mechanism of transfer is unknown. Full-length connexin 43 (Cx43, encoded by GJA1) and the truncated, internally translated isoform GJA1-20k have been implicated in mitochondrial transfer between highly oxidative cells, but have not been explored in orthopaedic tissues. Here, our goal was to investigate the role of Cx43 in MSC to chondrocyte mitochondrial transfer. In this study, we tested the hypotheses that (a) mitochondrial transfer from MSCs to chondrocytes is increased when chondrocytes are under oxidative stress and (b) MSC Cx43 expression mediates mitochondrial transfer to chondrocytes. METHODS: Oxidative stress was induced in immortalized human chondrocytes using tert-Butyl hydroperoxide (t-BHP) and cells were evaluated for mitochondrial membrane depolarization and reactive oxygen species (ROS) production. Human bone-marrow derived MSCs were transduced for mitochondrial fluorescence using lentiviral vectors. MSC Cx43 expression was knocked down using siRNA or overexpressed (GJA1 + and GJA1-20k+) using lentiviral transduction. Chondrocytes and MSCs were co-cultured for 24 h in direct contact or separated using transwells. Mitochondrial transfer was quantified using flow cytometry. Co-cultures were fixed and stained for actin and Cx43 to visualize cell-cell interactions during transfer. RESULTS: Mitochondrial transfer was significantly higher in t-BHP-stressed chondrocytes. Contact co-cultures had significantly higher mitochondrial transfer compared to transwell co-cultures. Confocal images showed direct cell contacts between MSCs and chondrocytes where Cx43 staining was enriched at the terminal ends of actin cellular extensions containing mitochondria in MSCs. MSC Cx43 expression was associated with the magnitude of mitochondrial transfer to chondrocytes; knocking down Cx43 significantly decreased transfer while Cx43 overexpression significantly increased transfer. Interestingly, GJA1-20k expression was highly correlated with incidence of mitochondrial transfer from MSCs to chondrocytes. CONCLUSIONS: Overexpression of GJA1-20k in MSCs increases mitochondrial transfer to chondrocytes, highlighting GJA1-20k as a potential target for promoting mitochondrial transfer from MSCs as a regenerative therapy for cartilage tissue repair in OA.

Sustainable bioinspired materials for regenerative medicine: balancing toxicology, environmental impact, and ethical considerations.

The pursuit of sustainable bioinspired materials for regenerative medicine demands a nuanced balance between scientific advancement, ethical considerations, and environmental consciousness. This abstract encapsulates a comprehensive perspective paper exploring the intricate dynamics of toxicology, environmental impact, and ethical concerns within the realm of bioinspired materials. As the landscape of regenerative medicine evolves, ensuring the biocompatibility and safety of these materials emerges as a pivotal challenge. Our paper delves into the multidimensional aspects of toxicity assessment, encompassing cytotoxicity, genotoxicity, and immunotoxicity analyses. Additionally, we shed light on the complexities of evaluating the environmental impact of bioinspired materials, discussing methodologies such as life cycle assessment, biodegradability testing, and sustainable design approaches. Amid these scientific endeavors, we emphasize the paramount importance of ethical considerations in bioinspired material development, navigating the intricate web of international regulations and ethical frameworks guiding medical materials. Furthermore, our abstract underscores the envisioned future directions and challenges in toxicology techniques, computational modeling, and holistic evaluation, aiming for a comprehensive understanding of the synergistic interplay between sustainable bioinspired materials, toxicity assessment, environmental stewardship, and ethical deliberation.

Comparison of Autologous and Allogeneic Adipose-Derived Stem Cells in Kidney Transplantation: Immunological Considerations and Therapeutic Efficacy.

Regenerative medicine shows significant potential in treating kidney diseases through the application of various types of stem and progenitor cells, including mesenchymal stem cells (MSCs), renal stem/progenitor cells, embryonic stem cells (ESCs), and induced pluripotent stem cells (iPSCs). Stem cells possess the unique ability to repair injured organs and improve impaired functions, making them a key element in the research of therapies for kidney tissue repair and organ regeneration. In kidney transplantation, reperfusion injury can cause tissue destruction, leading to an initially low glomerular filtration rate and long-term impact on function by creating irreversible interstitial fibrosis. MSCs have proven useful in repairing early tissue injury in animal models of kidney, lung, heart, and intestine transplantation. The use of stem cell therapies in solid organ transplantation raises the question of whether autologous or allogeneic cells should be preferred. Adipose-derived stem cells (ASCs), characterized by the lack of HLA Class II molecules and low expression of HLA Class I and co-stimulatory signals, are considered immune-privileged. However, the actual risk of graft rejection associated with allogeneic ASCs remains unclear. It has been demonstrated that donor-derived ASCs can promote the development of Treg cells in vitro, and some degree of tolerance induction has been observed in vivo. Nevertheless, a study comparing the efficacy of autologous and allogeneic ASCs in a rat model with a total MHC mismatch for kidney transplantation showed that donor-derived administration of ASCs did not improve the grafts' survival and was associated with increased mortality through an immunologically mediated mechanism. Given the lack of data, autologous ASCs appear to be a safer option in this research context. The aim of this review was to examine the differences between autologous and allogeneic ASCs in the context of their application in kidney transplantation therapies, considering potential immune reactions and therapeutic efficacy. Some have argued that ASCs harvested from end-stage renal disease (ESRD) patients may have lower regenerative potential due to the toxic effects of uremia, potentially limiting their use in transplantation settings. However, evidence suggests that the beneficial properties of ASCs are not affected by uremia or dialysis. Indeed, some investigators have demonstrated that ASCs harvested from chronic kidney disease (CKD) patients exhibit normal characteristics and function, maintaining consistent proliferative capacity and genetic stability over time, even after prolonged exposure to uremic serum Furthermore, no differences were observed in the response of ASCs to immune activation or their inhibitory effect on the proliferation of alloantigen-activated peripheral blood mononuclear cells between patients with normal or impaired renal function. This review presents the current achievements in stem cell research aimed at treating kidney diseases, highlighting significant progress and ongoing efforts in the development of stem cell-based therapies. Despite the encouraging results, further research is needed to overcome the current limitations and fully realize the potential of these innovative treatments. Advances in this field are crucial for developing effective therapies that can address the complex challenges associated with kidney damage and failure.