Regenerative Medicine Approaches Research Articles

Photobiomodulation Dose–Response on Adipose-Derived Stem Cell Osteogenesis in 3D Cultures

Osteoporosis and other degenerative bone diseases pose significant challenges to global healthcare systems due to their prevalence and impact on quality of life. Current treatments often alleviate symptoms without fully restoring damaged bone tissue, highlighting the need for innovative approaches like stem cell therapy. Adipose-derived mesenchymal stem cells (ADMSCs) are particularly promising due to their accessibility, abundant supply, and strong differentiation potential. However, ADMSCs tend to favor adipogenic pathways, necessitating the use of differentiation inducers (DIs), three-dimensional (3D) hydrogel environments, and photobiomodulation (PBM) to achieve targeted osteogenic differentiation. This study investigated the combined effects of osteogenic DIs, a fast-dextran hydrogel matrix, and PBM at specific wavelengths and fluences on the proliferation and differentiation of immortalized ADMSCs into osteoblasts. Near-infrared (NIR) and green (G) light, as well as their combination, were used with fluences of 3 J/cm2, 5 J/cm2, and 7 J/cm2. The results showed statistically significant increases in alkaline phosphatase levels, a marker of osteogenic differentiation, with G light at 7 J/cm2 demonstrating the most substantial impact on ADMSC differentiation. Calcium deposits, visualized by Alizarin red S staining, appeared as early as 24 h post-treatment in PBM groups, suggesting accelerated osteogenic differentiation. ATP luminescence assays indicated increased proliferation in all experimental groups, particularly with NIR and NIR-G light at 3 J/cm2 and 5 J/cm2. MTT viability and LDH membrane permeability assays confirmed enhanced cell viability and stable cell health, respectively. In conclusion, PBM significantly influences the differentiation and proliferation of hydrogel-embedded immortalized ADMSCs into osteoblast-like cells, with G light at 7 J/cm2 being particularly effective. These findings support the combined use of 3D hydrogel matrices and PBM as a promising approach in regenerative medicine, potentially leading to innovative treatments for degenerative bone diseases.

Starvation and Inflammation Modulate Adipose Mesenchymal Stromal Cells' Molecular Signature.

Mesenchymal stromal cells (MSCs) and their released factors (secretome) are intriguing options for regenerative medicine approaches based on the management of inflammation and tissue restoration, as in joint disorders like osteoarthritis (OA). Production strategy may modulate cells and secretome fingerprints, and for the latter, the effect of serum removal by starvation used in clinical-grade protocols has been underestimated. In this work, the effect of starvation on the molecular profile of interleukin 1 beta (IL1β)-primed adipose-derived MSCs (ASCs) was tested by assessing the expression level of 84 genes related to secreted factors and 84 genes involved in defining stemness potential. After validation at the protein level, the effect of starvation modulation in the secretomes was tested in a model of OA chondrocytes. IL1β priming in vitro led to an increase in inflammatory mediators' release and reduced anti-inflammatory potential on chondrocytes, features reversed by subsequent starvation. Therefore, when applying serum removal-based clinical-grade protocols for ASCs' secretome production, the effects of starvation must be carefully considered and investigated.

Comparative insight into the regenerative mechanisms of the adult brain in zebrafish and mouse: highlighting the importance of the immune system and inflammation in successful regeneration.

Regeneration, the complex process of restoring damaged or absent cells, tissues, and organs, varies considerably between species. The zebrafish is a remarkable model organism for its impressive regenerative abilities, particularly in organs such as the heart, fin, retina, spinal cord, and brain. Unlike mammals, zebrafish can regenerate with limited or absent scarring, a phenomenon closely linked to the activation of stem cells and immune cells. This review examines the unique roles played by the immune response and inflammation in zebrafish and mouse during regeneration, highlighting the cellular and molecular mechanisms behind their divergent regenerative capacities. By focusing on zebrafish telencephalic regeneration and comparing it to that of the rodents, this review highlights the importance of a well-controlled, acute, and non-persistent immune response in zebrafish, which promotes an environment conducive to regeneration. The knowledge gained from understanding the mechanisms of zebrafish regeneration holds great promises for the treatment of human neurodegenerative diseases and brain damage (stroke and traumatic brain injuries), as well as for the advancement of regenerative medicine approaches.

Landscape of Differentiation Potentials as a "Hallmark" in Oral-derived MSCs.

Mesenchymal stem cells (MSCs) offer clinical promise for use in cell therapy approaches for regenerative medicine. A therapeutic challenge is that MSCs from different tissues are phenotypically and functionally distinct. Therefore, this study aims to molecularly characterize oral-derived MSCs by defining one of the three hallmarks of MSCs, differentiation potential, to discern their true molecular identities. Three different populations of oral tissue MSCs (from alveolar bone-aBMSCs; from dental pulp-DPSCs; and from gingiva-GMSCs) from three different patients were isolated and cultured. These MSCs were characterized for their stemness by flow cytometry and multi-differentiation potential, and their RNA was also isolated and analyzed quantitatively with RNA sequencing. Total mRNA-seq was performed and differentially expressed genes (DEGs) were identified in pairwise (DPSCs vs. aBMSCs, GMSCs vs. aBMSCs, and GMSCs vs. DPSCs) and tissue-specific comparisons (aBMSCs vs. Others, DPSCs vs. Others, GMSCs vs. Others) (FDR, p<0.05 ). Further, these DEGs, either common between MSC populations or unique to a specific MSC population, were evaluated for pathways and biological processes. aBMSCs, DPSCs, and GMSCs were successfully isolated and characterized. The tissue-specific comparison revealed that DEGs were most numerous in DPSCs (693 genes) as compared to aBMSCs (103 genes) or DPSCs (232 genes). Statistically significant DEGs through pairwise comparisons present higher numbers in GMSCs vs. DPSCs (627) as compared to either DPSCs vs aBMSCs (286) or GMSCs vs. aBMSCs (82). Further analysis found that RUNX2, IBSP, SOX6, ACAN, and VCAM1 were significantly upregulated in aBMSCs. In DPSCs, BMP4 and IL6 were significantly downregulated, whereas AXL and NES were significantly upregulated. In GMSCs, AGPT1, SEMA4D, and PGDFA were significantly downregulated. Additionally, MAPK, PI3-AKT, and RAS signaling pathways were significantly regulated in GMSCs. Interestingly, aBMSCs and DPSCs revealed positive regulation of osteoblast differentiation, whereas GMSCs revealed negative regulation of osteoblast differentiation. DPSCs also revealed negative regulation of angiogenesis. Oral-derived MSCs have an inherent "landscape" of differentiation defined by their tissue of origin; yet this differentiation potential can be modulated by their microenvironment.

Effect of Cellular Dosage of Bone Marrow Aspiration Concentrate on the Radiological Outcomes in Knee Osteoarthritis: A Phase I Dose-Escalation Study.

Knee osteoarthritis(KOA), a chronic degenerative disease, significantly impairs quality of life due to pain and mobility limitations. Traditional treatments focus on symptom management without addressing the underlying disease progression, leading to a growing interest in regenerative medicine approaches. Bone marrow aspirate concentrate (BMAC), rich in mesenchymal stem cells and growth factors, has shown potential for cartilage repair and symptom relief in KOA. Despite promising outcomes, the optimal BMAC dosage for knee OA treatment remains undetermined. This study aims to evaluate the radiological outcomes of varying BMAC dosages in knee OA treatment. This prospective controlled dose-escalation study involved 75 patients with early-stage knee OA, categorized into three groups based on BMAC dosage administered 10x106 cells (low-dose group), 50×106 cells (medium-dose group), or 100x106 cells (high-dose group). All the patients underwent a single intra-articular injection of BMAC and were monitored over a year. The primary outcomes include magnetic resonance observation of cartilage repair tissue (MOCART 2.0) score to assess the cartilage. We noted significant improvement in the overall MOCART score (p=0.027) and subchondral change sub-score (p=0.048) and defect filling sub-score (p=0.025) in the medium- and high-dose cohorts compared to the low-dose cohort at 1year follow-up. Although we noted positive correlation between the clinical and radiological outcome (r=0.43), we did not find any significant different in the clinical outcome between the treatment groups. BMAC for OA knee resulted in significant improvement in the radiological scores compared to the baseline. Medium and high doses of BMAC result in significantly higher radiological scores compared to low-dose BMAC at 1year. However, the radiological improvement did not translate into functional improvement, irrespective of the dosage administered at 1year. Further research is necessary on the long-term outcomes to understand and optimize the dosing strategy based on clinico-radiological results.

Tissue engineering and regenerative medicine approaches in colorectal surgery.

Tissue engineering and regenerative medicine (TERM) is an emerging field that has provided new therapeutic opportunities by delivering innovative solutions. The development of nontraditional therapies for previously unsolvable diseases and conditions has brought hope and excitement to countless individuals globally. Many regenerative medicine therapies have been developed and delivered to patients clinically. The technology platforms developed in regenerative medicine have been expanded to various medical areas; however, their applications in colorectal surgery remain limited. Applying TERM technologies to engineer biological tissue and organ substitutes may address the current therapeutic challenges and overcome some complications in colorectal surgery, such as inflammatory bowel diseases, short bowel syndrome, and diseases of motility and neuromuscular function. This review provides a comprehensive overview of TERM applications in colorectal surgery, highlighting the current state of the art, including preclinical and clinical studies, current challenges, and future perspectives. This article synthesizes the latest findings, providing a valuable resource for clinicians and researchers aiming to integrate TERM into colorectal surgical practice.

Macrophage plasticity: signaling pathways, tissue repair, and regeneration.

Macrophages are versatile immune cells with remarkable plasticity, enabling them to adapt to diverse tissue microenvironments and perform various functions. Traditionally categorized into classically activated (M1) and alternatively activated (M2) phenotypes, recent advances have revealed a spectrum of macrophage activation states that extend beyond this dichotomy. The complex interplay of signaling pathways, transcriptional regulators, and epigenetic modifications orchestrates macrophage polarization, allowing them to respond to various stimuli dynamically. Here, we provide a comprehensive overview of the signaling cascades governing macrophage plasticity, focusing on the roles of Toll-like receptors, signal transducer and activator of transcription proteins, nuclear receptors, and microRNAs. We also discuss the emerging concepts of macrophage metabolic reprogramming and trained immunity, contributing to their functional adaptability. Macrophage plasticity plays a pivotal role in tissue repair and regeneration, with macrophages coordinating inflammation, angiogenesis, and matrix remodeling to restore tissue homeostasis. By harnessing the potential of macrophage plasticity, novel therapeutic strategies targeting macrophage polarization could be developed for various diseases, including chronic wounds, fibrotic disorders, and inflammatory conditions. Ultimately, a deeper understanding of the molecular mechanisms underpinning macrophage plasticity will pave the way for innovative regenerative medicine and tissue engineering approaches.

Recent Advances in the Management of Non-rheumatic Atrial Fibrillation: A Comprehensive Review.

Atrial fibrillation (AF) is a prevalent cardiac arrhythmia characterized by irregular atrial electrical activity, posing significant challenges to patient management and healthcare systems worldwide. Non-rheumatic AF, distinct from AF due to rheumatic heart disease, encompasses a spectrum of etiologies, including hypertension, coronary artery disease, and structural heart abnormalities. This review examines the latest advancements in managing non-rheumatic AF, encompassing diagnostic approaches, pharmacological therapies, and innovative non-pharmacological interventions. Diagnostic strategies ranging from traditional electrocardiography to advanced imaging modalities are explored alongside emerging biomarkers and wearable technologies facilitating early detection and management. Pharmacological management options, including novel anticoagulants and rhythm control agents, are evaluated in light of current guidelines and recent clinical trials. Non-pharmacological interventions, such as catheter ablation and device-based therapies, are discussed regarding their evolving techniques and outcomes. Special considerations for diverse patient populations, including elderly individuals and athletes, are addressed, emphasizing personalized approaches to optimize therapeutic outcomes. The review concludes with insights into future directions for AF management, highlighting promising avenues in gene therapy, regenerative medicine, and precision medicine approaches. By synthesizing recent research findings and clinical innovations, this review provides a comprehensive overview of the dynamic landscape of non-rheumatic AF management, offering insights for clinicians, researchers, and healthcare stakeholders.

Biliary atresia.

Biliary atresia (BA) is a progressive inflammatory fibrosclerosing disease of the biliary system and a major cause of neonatal cholestasis. It affects 1:5,000-20,000 live births, with the highest incidence in Asia. The pathogenesis is still unknown, but emerging research suggests a role for ciliary dysfunction, redox stress and hypoxia. The study of the underlying mechanisms can be conceptualized along the likely prenatal timing of an initial insult and the distinction between the injury and prenatal and postnatal responses to injury. Although still speculative, these emerging concepts, new diagnostic tools and early diagnosis might enable neoadjuvant therapy (possibly aimed at oxidative stress) before a Kasai portoenterostomy (KPE). This is particularly important, as timely KPE restores bile flow in only 50-75% of patients of whom many subsequently develop cholangitis, portal hypertension and progressive fibrosis; 60-75% of patients require liver transplantation by the age of 18 years. Early diagnosis, multidisciplinary management, centralization of surgery and optimized interventions for complications after KPE lead to better survival. Postoperative corticosteroid use has shown benefits, whereas the role of other adjuvant therapies remains to be evaluated. Continued research to better understand disease mechanisms is necessary to develop innovative treatments, including adjuvant therapies targeting the immune response, regenerative medicine approaches and new clinical tests to improve patient outcomes.

Rankl genetic deficiency and functional blockade undermine skeletal stem and progenitor cell differentiation

BackgroundSkeletal Stem Cells (SSCs) are required for skeletal development, homeostasis, and repair. The perspective of their wide application in regenerative medicine approaches has supported research in this field, even though so far results in the clinic have not reached expectations, possibly due also to partial knowledge of intrinsic, potentially actionable SSC regulatory factors. Among them, the pleiotropic cytokine RANKL, with essential roles also in bone biology, is a candidate deserving deep investigation.MethodsTo dissect the role of the RANKL cytokine in SSC biology, we performed ex vivo characterization of SSCs and downstream progenitors (SSPCs) in mice lacking Rankl (Rankl−/−) by means of cytofluorimetric sorting and analysis of SSC populations from different skeletal compartments, gene expression analysis, and in vitro osteogenic differentiation. In addition, we assessed the effect of the pharmacological treatment with the anti-RANKL blocking antibody Denosumab (approved for therapy in patients with pathological bone loss) on the osteogenic potential of bone marrow-derived stromal cells from human healthy subjects (hBMSCs).ResultsWe found that, regardless of the ossification type of bone, osteochondral SSCs had a higher frequency and impaired differentiation along the osteochondrogenic lineage in Rankl−/− mice as compared to wild-type. Rankl−/− mice also had increased frequency of committed osteochondrogenic and adipogenic progenitor cells deriving from perivascular SSCs. These changes were not due to the peculiar bone phenotype of increased density caused by lack of osteoclast resorption (defined osteopetrosis); indeed, they were not found in another osteopetrotic mouse model, i.e., the oc/oc mouse, and were therefore not due to osteopetrosis per se. In addition, Rankl−/− SSCs and primary osteoblasts showed reduced mineralization capacity. Of note, hBMSCs treated in vitro with Denosumab had reduced osteogenic capacity compared to control cultures.ConclusionsWe provide for the first time the characterization of SSPCs from mouse models of severe recessive osteopetrosis. We demonstrate that Rankl genetic deficiency in murine SSCs and functional blockade in hBMSCs reduce their osteogenic potential. Therefore, we propose that RANKL is an important regulatory factor of SSC features with translational relevance.

Exosomes derived from Polygonum multiflorum-treated human dental pulp stem cells (hDPSCs): New approach in regenerative medicine

Extracellular vesicles (EVs) are currently being extensively utilized in clinical trials. Our previous study demonstrated that the conditioned medium of human dental pulp stem cells (hDPSCs) treated by 2,3,5,4′-tetrahydroxystilbene-2-O-β-D-glucoside (THSG) exhibits biological activity and anti-inflammatory responses, which are believed to be regulated by EVs. To date, no study has thoroughly investigated the potential of the exosomes released by THSG-treated hDPSCs. In this study, we utilized the conditioned medium (CM) of hDPSCs with/without THSG stimulation to compare the differences in exosome extraction using ultracentrifugation (UC), tangential flow filtration (TFF), and TFF combined with size-exclusion chromatography (TFF + SEC) methods, aiming to establish an effective purification method. Subsequently, we analyzed the contents of the exosomes using proteomic strategy. The results showed that TFF + SEC was more effective in reducing protein contamination compared to CM and TFF alone. TFF effectively concentrated large-scale CM and maintained exosome particle sizes consistently around 85–100 nm. Flow cytometry analysis revealed that the presence of THSG increased exosome secretion from hDPSCs, concurrently leading to the identification of 219 unique proteins through proteomic analysis, including BMP-1, VEGF, and members of the MMP family. Compared to non-lyophilized exosomes, lyophilized exosomes showed no change in protein activity, indicating that lyophilization was an effective preservation method. Collectively, these findings present a combined extraction strategy for dental stem cell exosomes and reveal the high purity and proteome composition of THSG-exosomes, thereby highlighting their potential applications in regenerative therapy.

Mesenchymal stem cells and their derived exosomes in multiple sclerosis disease: from paper to practice.

Multiple sclerosis (MS) is a chronic neurodegenerative, inflammatory, and demyelinating disease of the central nervous system (CNS). Current medicines are not sufficient to control the inflammation and progressive damage to the CNS that is known in MS. These drawbacks highlight the need for novel treatment options. Cell therapy can now be used to treat complex diseases when conventional therapies are ineffective. Mesenchymal stem cells (MSCs) are a diverse group of multipotential non-hematopoietic stromal cells which have immunomodulatory, neurogenesis, and remyelinating capacity. Their advantageous effects mainly rely on paracrine, cell-cell communication and differentiation properties which introduced them as excellent candidates for MS therapy. Exosomes, as one of the MSCs secretomes, have unique properties that make them highly promising candidates for innovative approach in regenerative medicine. This review discusses the therapeutic potential of MSCs and their derived exosomes as a novel treatment for MS, highlighting the differences between these two approaches.

Highly parallel production of designer organoids by mosaic patterning of progenitors

Organoids derived from human stem cells are a promising approach for disease modeling, regenerative medicine, and fundamental research. However, organoid variability and limited control over morphological outcomes remain as challenges. One open question is the extent to which engineering control over culture conditions can guide organoids to specific compositions. Here, we extend a DNA "velcro" cell patterning approach, precisely controlling the number and ratio of human induced pluripotent stem cell-derived progenitors contributing to nephron progenitor (NP) organoids and mosaic NP/ureteric bud (UB) tip cell organoids within arrays of microwells. We demonstrate long-term control over organoid size and morphology, decoupled from geometric constraints. We then show emergent trends in organoid tissue proportions that depend on initial progenitor cell composition. These include higher nephron and stromal cell representation in mosaic NP/UB organoids vs. NP-only organoids and a "goldilocks" initial cell ratio in mosaic organoids that optimizes the formation of proximal tubule structures.

Autologization of Exosomes with Deparenchymized Adipose Tissue: An Innovative Approach for Regenerative Medicine and Surgery.

Among all regenerative applications developed in recent years, the use of exosomes has generated by far the greatest interest. Exosome products from allogeneic and xenogeneic sources are available on the market. A key challenge is controlling the effects of nonautologous exosomes. We hypothesized that combining exosomes with a patient's own extracellular matrix (ECM) can create "autologization," enabling control over their effects. This study aimed to provide the rationale and a guide for future research exploring the autologization of exosome applications using deparenchymized adipose tissue (DPAT). DPAT adipose tissue was achieved using 1200-, 400-, and 35-micrometer blades in an ultrasharp blade system (Adinizer), and then "autologization" was achieved by combining the obtained DPAT with allogeneic exosomes. DPAT was evaluated histochemically, and exosomes were counted and analyzed with the Nanosight device. The DPAT process using ultrasharp blades is easily performed. DPAT obtained from adipose tissue was then combined with allogenic exosomes. It has been demonstrated histopathologically that adipocytes are eliminated in deparenchymized fat tissue, and only ECM and stromal cells remain. It has also been proven that the number of exosomes is not affected by the combination. This study introduces two novel concepts previously unknown in the literature, "deparenchymization" and "autologization," representing an innovative approach in plastic surgery and regenerative medicine. Our novel approach enriches regenerative cells while preserving critical ECM signals, overcoming the limitations of existing isolation methods. Extensive research is still needed, but autologization using DPAT ECM holds great promise for translating exosome-based treatments into practice.

Thymidylate synthase disruption to limit cell proliferation in cell therapies

Stem and progenitor cells hold great promise for regenerative medicine and gene therapy approaches. However, transplantations of living cells entail a fundamental risk of unwanted growth, potentially exacerbated by CRISPR-Cas9 or other genetic manipulations. Here, we describe a safety system to control cell proliferation while allowing robust and efficient cell manufacture, without any added genetic elements. Inactivating TYMS, a key nucleotide metabolism enzyme, in several cell lines resulted in cells that proliferate only when supplemented with exogenous thymidine. Under supplementation, TYMS-/--pluripotent stem cells proliferate, produce teratomas and successfully differentiate into potentially therapeutic cell types such as pancreatic beta-cells. Our results suggest that supplementation with exogenous thymidine affects stem cell proliferation, but not the function of stem cell-derived cells. After differentiation, postmitotic cells do not require thymidine in vitro or in vivo, as shown by the production of functional human insulin in mice up to 5 months after implantation of stem-cell derived pancreatic tissue.

Increased Cellular Dosage of Bone Marrow Aspiration Concentrate Does Not Translate to Increased Clinical Effectiveness in Knee Osteoarthritis: A Phase I Dose Escalation Study.

Knee osteoarthritis (KOA), a chronic degenerative disease, significantly impairs quality of life due to pain and mobility limitations. Traditional treatments focus on symptom management without addressing the underlying disease progression, leading to a growing interest in regenerative medicine approaches. Bone marrow aspirate concentrate (BMAC), rich in mesenchymal stem cells and growth factors, has shown potential for cartilage repair and symptom relief in KOA. Despite promising outcomes, the optimal BMAC dosage for knee OA treatment remains undetermined. This study aims to evaluate the clinical efficacy and safety of varying BMAC dosages in knee OA treatment. This prospective controlled dose-escalation study involved 75 patients with early-stage knee OA, categorized into three groups based on BMAC dosage administered 10 × 106 cells (low-dose group), 50 × 106 cells (medium-dose group), or 100 × 106 cells (high-dose group). All the patients underwent a single intra-articular injection of BMAC and were monitored over a year. The primary outcomes include Visual Analog Scale (VAS) for pain and the Knee Injury and Osteoarthritis Outcome Score (KOOS) for joint function recorded at baseline, 1, 3, 6, and 12months post-intervention. Adverse events were also documented. Significant clinical improvements in VAS and KOOS scores were noted across all groups at all time points compared to the baseline. However, these improvements did not significantly differ between dosage groups throughout the follow-up period. Adverse effects were minimal and primarily consisted of transient post-injection pain and effusion, with no dose-dependent increase in complications. BMAC treatment for knee OA is safe and demonstrates potential for significant pain relief and functional improvement, irrespective of the dosage administered within the tested range. The lack of significant differences among varying dosages suggests a plateau in therapeutic efficacy beyond a certain threshold. Further research is necessary on the long-term outcomes to optimize the dosing strategy.

Exploring Novel Therapeutic Approaches for Chronic Kidney Disease

Chronic kidney disease (CKD) is a significant global health burden, affecting millions of individuals worldwide. Despite current treatment strategies focusing on glycemic control and renin-angiotensin system blockade, these approaches merely delay the progression to end-stage renal disease (ESRD) and are associated with potential adverse effects. Recent advancements in our understanding of the complex pathophysiology of CKD have unveiled various unique processes contributing to its development, including vascular alterations, podocyte and renal epithelial cell loss, matrix deposition, inflammation, and metabolic dysregulation. This comprehensive review critically evaluates novel therapeutic approaches targeting these distinct pathways implicated in CKD pathogenesis. Strategies discussed include endothelial glycocalyx restoration, endothelin receptor antagonists, anti-apoptotic and podocyte regeneration therapies, anti-inflammatory and antioxidant agents, sodium-glucose co-transporter 2 (SGLT2) inhibitors, mitochondria-targeted therapies, anti-fibrotic agents, and interventions targeting epithelial-to-mesenchymal transition (EMT). While preclinical studies have demonstrated promising results for many of these approaches, their translation to clinical settings has been challenging due to safety concerns, lack of efficacy in trials, and the heterogeneity of CKD pathogenesis. The review highlights the importance of identifying appropriate patient populations, developing precision medicine strategies, exploring combination therapies, and leveraging novel drug delivery systems and regenerative medicine approaches to overcome current obstacles and improve therapeutic outcomes for CKD patients

Neuronal Vulnerability to Degeneration in Parkinson's Disease and Therapeutic Approaches.

Parkinson's disease is the second most common neurodegenerative disease affecting millions of people worldwide. Despite the crucial threat it poses, currently, no specific therapy exists that can completely reverse or halt the progression of the disease. Parkinson's disease pathology is driven by neurodegeneration caused by the intraneuronal accumulation of alpha-synuclein (α-syn) aggregates in Lewy bodies in the substantia nigra region of the brain. Parkinson's disease is a multiorgan disease affecting the central nervous system (CNS) as well as the autonomic nervous system. A bidirectional route of spreading α-syn from the gut to CNS through the vagus nerve and vice versa has also been reported. Despite our understanding of the molecular and pathophysiological aspects of Parkinson's disease, many questions remain unanswered regarding the selective vulnerability of neuronal populations, the neuromodulatory role of the locus coeruleus, and alpha-synuclein aggregation. This review article aims to describe the probable factors that contribute to selective neuronal vulnerability in Parkinson's disease, such as genetic predisposition, bioenergetics, and the physiology of neurons, as well as the interplay of environmental and exogenous modulators. This review also highlights various therapeutic strategies with cell transplants, through viral gene delivery, by targeting α-synuclein and aquaporin protein or epidermal growth factor receptors for the treatment of Parkinson's disease. The application of regenerative medicine and patient-specific personalized approaches have also been explored as promising strategies in the treatment of Parkinson's disease.

A Novel Diabetic Arthritic Model in Rats Induced by Streptozotocin, High-Fat Diet, and Complete Freund's Adjuvant.

Ankle arthrodesis is one of the treatments of choice, particularly in late-stage and unstable diabetic Charcot arthropathy. Unfortunately, poor healing capacity might play a role in the high nonunion rate (10-40%). The advancement in regenerative medicine opens a new horizon for enhancing fusion after ankle arthrodesis in patients with poor healing capacity. However, a suitable small animal model is warranted to study the effectivity of these regenerative medicine approaches. Streptozotocin (STZ)-induced diabetes models and adjuvant-induced arthritis models with complete Freund's adjuvant are two established models. However, no study has combined those two models to make a diabetic arthritic model that more closely resembles the condition in Charcot arthropathy. Twenty male Sprague-Dawley rats were assigned into five groups, consisting of one control group, and four diabetic groups which were induced by STZ injection and a high-fat diet. Among these diabetic rats, two groups received complete Freund's adjuvant (CFA) injections to the left ankle of the hind limb. The control group, one of the diabetic-only groups, and one of the arthritic-diabetic-induced groups were euthanized at 4 weeks after STZ induction, and the remainder were euthanized 6 weeks after STZ induction. Clinical, radiological, and histological examinations were then compared in all five groups. Diabetic status was successfully achieved in the model, which was maintained until the completion of the study. The CFA-induced ankles were significantly larger than the contralateral ankles in all groups (p<0.05). Histopathological evaluation confirmed arthritic changes in the CFA-induced group with less variability after 4 weeks of arthritis induction. This rat model of arthritic diabetic mimics the progressive and chronic nature of Charcot arthropathy in humans. This model can be further use to study treatments that might enhance the fusion rate in ankle arthrodesis in healing-defective patients such as those with diabetes. 5.

Current Strategies and Therapeutic Applications of Mesenchymal Stem Cell-Based Drug Delivery.

Mesenchymal stem cells (MSCs) have emerged as a promising approach for drug delivery strategies because of their unique properties. These strategies include stem cell membrane-coated nanoparticles, stem cell-derived extracellular vesicles, immunomodulatory effects, stem cell-laden scaffolds, and scaffold-free stem cell sheets. MSCs offer advantages such as low immunogenicity, homing ability, and tumor tropism, making them ideal for targeted drug delivery systems. Stem cell-derived extracellular vesicles have gained attention for their immune properties and tumor-homing abilities, presenting a potential solution for drug delivery challenges. The relationship between MSC-based drug delivery and the self-renewal and differentiation capabilities of MSCs lies in the potential of engineered MSCs to serve as effective carriers for therapeutic agents while maintaining their intrinsic properties. MSCs exhibit potent immunosuppressive functions in MSC-based drug delivery strategies. Stem cell-derived EVs have low immunogenicity and strong therapeutic potential for tissue repair and regeneration. Scaffold-free stem cell sheets represent a cutting-edge approach in regenerative medicine, offering a versatile platform for tissue engineering and regeneration across different medical specialties. MSCs have shown great potential for clinical applications in regenerative medicine because of their ability to differentiate into various cell types, secrete bioactive factors, and modulate immune responses. Researchers are exploring these innovative approaches to enhance drug delivery efficiency and effectiveness in treating various diseases.