Cell-based therapy is a new direction of treatment of diseases such as type 1 diabetes mellitus (T1DM); but unfortunately, its severe side effects include immunogenicity and tumor development. Using Mesenchymal stem cells conditioned medium (MSCs-CM) may be an alternative therapy to avoid stem cell risks, preserving effectiveness and demonstrating noticeably increased levels of cytokines, angiogenic factors, and growth factors that encourage and support regenerative processes. In the current work, we examined the effects of MSCs-CM injected in tail vein and pancreas directly compared with the standard antidiabetic drug, glimepiride in streptozotocin-induced type 1 diabetic rats. Fifty adults Male Wistar rats were allocated equally into five groups: normal, diabetic control and three diabetic groups treated respectively with glimepiride, MSCs-CM injected daily into tail vein (MSCs-CMT) and MSCs-CM injected directly in pancreas (MSCs-CMP); all treatments continued for 28 days. The treatments produced a significant improvement in blood glucose level and glycosylated hemoglobin A1c (HbA1c), serum insulin level and lipid panel, and pancreas apoptosis-related markers including B cell lymphoma-2 (Bcl-2) and vimentin. In addition, the treatments resulted in suppression in the oxidation stress and enhancement in the antioxidant, which were manifested by the suppressed lipid peroxidation and the increased antioxidant markers (glutathione, catalase and superoxide dismutase) in the pancreas. In association with the significant decrease in tumour necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1β) and a significant increase in interleukin-10 (IL-10) levels, the inflammatory mediator nuclear factor-kappa B (NF-κB) expression was significantly decreased by MSCs-CMT and MSCs-CMP. The histological amelioration of the pancreatic islet cells assured our study especially in MSCs-CMP group than MSCs-CMT which supports islet regeneration and elevated circulating insulin. These results imply that MSCs-CM infusion has therapeutic benefits in T1DM rats and may be a viable novel therapeutic approach; MSCs-CMP was shown to be more effective than glimepiride and MSCs-CMT. The mechanisms of antidiabtic actions may be mediated via the antioxidant, anti-apoptotic and anti-inflammatory effects.

The proteins secreted by human umbilical cord mesenchymal stem cells (hUC-MSCs) may enhance tissue regeneration and wound healing. Traditional hUC-MSC cultures may not be enough since they undergo recurrent cellular senescence during large-scale production. This decreases the therapeutic ability of hUC-MSCs by altering genes and proteins that control stemness, proliferation, and protein release. Human cord blood serum (CBS) and the middle-density technique were used to evaluate hUC-MSC regeneration ability. To evaluate early-passage hMSCs for secretome-based therapies, they were expanded and secreted in vitro. After 4 days, hUC-MSCs cultivated at 3000 cells/cm2 and supplemented with 1 ng/ml CBS showed increased growth, cell proliferation, and a much lower population doubling time. CBS treatment reduced CD34, CD45, and HLA-DR levels in human umbilical cord mesenchymal stem cells (hUC-MSCs) by less than 2 %. Positive markers such CD73, CD90, and CD105 were found at >97 %, like control hUC-MSCs. Over extended culture, this combination culture can increase survival, proliferation, and stemness and postpone cell death and hUC-MSC senescence. The protein profile and hUC-MSC secretion were improved to make MSC secretion protein therapeutic. This improves cell-free treatment, proliferation, and wound healing in human skin cells. To improve cell-based transplantation or cosmeceutical manufacturing, this technique can boost hUC-MSC regeneration capacity.

SHEDs have demonstrated significant potential in cell therapy due to their superior proliferation rate, self-renewal and differentiation capacity (particularly neurogenesis attributed to their neural crest origin), and the less invasive procedure required for tissue collection compared to other stem cells. However, there is no established criterion to verify the minimum qualification to select one from numerous candidates, especially for SHEDs' cultured FBS-free medium for clinic application. For that, we performed a characteristic analysis containing the growth rate, colony-forming unit (CFU) number, average colony size, and migration capacity with hPL-cultured SHEDs from 21 different donors, and we suggest the result as a minimum standard to filter out unqualified candidates. In addition, in the secretome analysis to predict the paracrine effect, it was found that upregulated proteins compared to the control were related to angiogenesis, immune response, and BMP signaling, and this was found to have a strong correlation only with protein concentration. This study presents a minimum standard for selecting cell therapy candidates and suggests the protein concentration of a conditioned medium as a cost-effective tool to expect the paracrine effect of SHEDs.

Improvements in the treatment of cartilage require insights into the secretory profile of mesenchymal stem cells (MSCs). Apart from their differentiation potential, MSCs secrete a multitude of molecules with therapeutic properties that benefit chondrogenesis and immunomodulation. Previously, we employed a small-panel microarray to demonstrate differences within conditioned medium (CM) of MSCs that were mechanically stimulated within a joint-mimicking bioreactor and their unloaded controls. This study analyzed the proteomic content within CM from 4 week mechanically loaded MSCs with a larger protein microarray. We examined the chondrogenic effect of CM by administration to MSC and chondrocyte pellet cultures, as well as functional changes in T cell proliferation. CM from mechanically loaded samples shows a promising push towards chondrogenic phenotypes within both pellet cultures. Inhibition of T cell proliferation was also observed. This in vitro model could enhance our understanding how mechanical load induces changes in MSC secretome benefitting cartilage healing.

Inflammation mechanisms play a critical role in muscle homeostasis, and in Muscular Dystrophies (MDs), the myofiber damage triggers chronic inflammation which significantly controls the disease progression. Immunomodulatory strategies able to target inflammatory pathways and mitigate the immune-mediated damage in MDs may provide new therapeutic options. Owing to its capacity of influencing the immune response and enhancing tissue repair, stem cells' secretome has been proposed as an adjunct or standalone treatment for MDs. In this review study, we discuss the challenging points related to the inflammation condition characterizing MD pathology and provide a concise summary of the literature supporting the potential of perinatal stem cells in targeting and modulating the MD inflammation.

Batch-to-batch reproducibility and robust quality assessment are crucial for producing cell-free biologics, such as conditioned medium (CM) derived from mesenchymal stem/stromal cells (MSCs). This study investigated the effects of freezing CM at -80 °C prior to concentration, a step that could occur in large scale pipelines, compared to freshly processed CM. Quality assessment included total protein quantification; extracellular vesicle evaluation using nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and cytofluorimetry; and biochemical analysis using Raman spectroscopy. The freezing process resulted in a 34% reduction in total protein content, as confirmed for selected bioactive mediators, and significant depletion of specific particle types, particularly larger ones. Interestingly, the total particle concentration and polydispersity remained stable. Alterations in Raman spectra highlighted changes in protein, lipid, and nucleic acid content. These findings demonstrate that even routine steps like freezing can alter CM composition, likely due to temperature-induced structural changes in biological molecules. Careful consideration of pre- and intra-processing handling temperatures is critical for preserving the integrity of CM and ensuring consistent quality. This study emphasizes the importance of refining manufacturing protocols in the production of cell-free biologics.

Osteoarthritis (OA) presents a significant therapeutic challenge, with few options for preserving joint cartilage and repairing associated tissue damage. Inflammation is a pivotal factor in OA-induced cartilage deterioration and synovial inflammation. Recently, exosomes derived from human umbilical cord mesenchymal stem cells (HucMSCs) have gained recognition as a promising noncellular therapeutic modality, but their use is hindered by the challenge of harvesting a sufficient number of exosomes with effective therapeutic efficacy. Given that HucMSCs are highly sensitive to microenvironmental signals, we hypothesized that priming HucMSCs within a proinflammatory environment would increase the number of exosomes secreted with enhanced anti-inflammatory properties. Subsequent miRNA profiling and pathway analysis confirmed that interleukin-1 beta (IL-1β)-induced exosomes (C-Exos) exert positive effects through miRNA regulation and signaling pathway modulation. In vitro experiments revealed that C-Exos enhance chondrocyte functionality and cartilage matrix production, as well as macrophage polarization, thereby enhancing cartilage repair. C-Exos were encapsulated in hyaluronic acid hydrogel microspheres (HMs) to ensure sustained release, leading to substantial improvements in the inflammatory microenvironment and cartilage regeneration in a rat OA model. This study outlines a strategy to tailor exosome cargo for anti-inflammatory and cartilage regenerative purposes, with the functionalized HMs demonstrating potential for OA treatment.

Multiple sclerosis (MS), a chronic autoimmune disorder of the central nervous system (CNS), is characterized by inflammation, demyelination, and neurodegeneration, leading to diverse clinical manifestations such as fatigue, sensory impairment, and cognitive dysfunction. Current pharmacological treatments primarily target immune modulation but fail to arrest disease progression or entirely reverse CNS damage. Mesenchymal stem cell (MSC) therapy offers a promising alternative, leveraging its immunomodulatory, neuroprotective, and regenerative capabilities. This review provides an in-depth analysis of MSC mechanisms of action, including immune system regulation, promotion of remyelination, and neuroregeneration. It examines preclinical studies and clinical trials evaluating the efficacy, safety, and limitations of MSC therapy in various MS phenotypes. Special attention is given to challenges such as delivery routes, dosing regimens, and integrating MSCs with conventional therapies. By highlighting advancements and ongoing challenges, this review underscores the potential of MSCs to revolutionize MS treatment, paving the way for personalized and combinatory therapeutic approaches.

Osteoarthritis is a degenerative disease of cartilage, and exosome derived from mesenchymal stem cells (MSCs) are considered promising for treating inflammatory musculoskeletal disorders, although their mechanisms are not fully understood. This study aimed to investigate the effects of exosomes derived from canine bone marrow mesenchymal stem cells (cBMSCs-Exos) on the expression of inflammatory factors and genes related cartilage matrix metabolism in IL-1β-induced canine chondrocytes. Canine BMSCs were isolated and characterized for surface markers and trilineage differentiation. Exosomes were then extracted and performed surface labeling detection. Canine chondrocytes were exposed to IL-1β to mimic osteoarthritis in vitro. Subsequently, the chondrocytes were treated with exosomes from BMSCs, and the expression levels of related genes and IL-6 protein were assessed. The mesenchymal stem cells isolated from bone marrow and cultured exhibited positive CD44 and CD90, negative expression of CD45 and HLA, and demonstrated potential to differentiate into adipocytes, osteoblasts and chondrocytes. Exosomes from BMSCs exhibited positivity expression of CD9, CD63 and CD81. Treatment with exosomes significantly reduced IL-6 and TNF-α mRNA levels induced by IL-1β, as well as IL-6 protein expression. Additionally, a significant decrease was observed in the mRNA levels catabolic marker genes MMP-13, ADAMTS-5, and COX2. Conversely, there was a significant increase in the mRNA levels of anti-inflammatory cytokines IL-4, IL-10, and anabolic marker genes, such as COL2A1, ACAN, and SOX9. cBMSCs-Exos play a vital role in cartilage protection by suppressing the expression of pro-inflammatory and anabolic genes while simultaneously enhancing the expression of genes involved in synthesis metabolism.

The blood-brain barrier (BBB) is a specialized network that maintains central nervous system homeostasis. Disruption of the BBB can lead to neuronal damage and contribute to neurodegenerative diseases like Parkinson's disease (PD), characterized by alpha-synuclein (αSN) aggregation, which forms intracellular inclusions. Mesenchymal stem cells (MSCs) have shown promise in alleviating the severity of neurological diseases through their paracrine secretions. However, the impact of MSCs secretome on the BBB remains largely unclear. In this study, we investigated the effect of human umbilical cord-derived MSCs (hUC-MSCs) secretome on the BBB in the presence of toxic αSN-aggregates (αSN-AGs). Using in vitro BBB models established through mono- and co-culture systems of hCMEC/D3 cells, we assessed the influence of the secretome on the cytotoxicity and inflammatory responses induced by αSN-AGs. Our results demonstrate that the hUC-MSCs secretome exerts protective effects by mitigating the toxic effects of αSN-AGs on the BBB. Specifically, this study shows a notable reduction in cytotoxicity and inflammation. Our findings highlight the potential of hUC-MSCs secretome as a promising candidate for innovative, cell-free therapies in PD treatment. Furthermore, we propose an optimized method for isolating MSCs from umbilical cord tissue, aimed at facilitating future research on the therapeutic applications of these cells.

Spinal cord injury (SCI) leads to acute tissue damage that disrupts the microenvironmental homeostasis of the spinal cord, inhibiting cell survival and function, and thereby undermining treatment efficacy. Traditional stem cell therapies have limited success in SCI, due to the difficulties in maintaining cell survival and inducing sustained differentiation into neural lineages. A new solution may arise from controlling the fate of stem cells by creating an appropriate mechanical microenvironment. In this study, mechanical response stem cell complex (MRSCC) is created as an innovative therapeutic strategy for SCI, utilizing 3D bioprinting technology and gelatin microcarriers (GM) loaded with mesenchymal stem cells (MSCs). GM creates an optimal microenvironment for MSCs growth and paracrine activity. Meanwhile, 3D bioprinting allows accurate control of spatial pore architecture and mechanical characteristics of the cell construct to encourage neuroregeneration. The mechanical microenvironment created by MRSCC is found to activate the Piezo1 channel and prevent excessive nuclear translocation of YAP, thereby increasing neural-related gene expression in MSCs. Transplanting MRSCC in rats with spinal cord injuries boosts sensory and motor recovery, reduces inflammation, and stimulates the regeneration of neurons and glial cells. The MRSCC offers a new tissue engineering solution that can promote spinal cord repair.

Orthobiologic injections including platelet-rich plasma (PRP) and cell-based injections are becoming increasingly popular. Evidence suggests that these therapies can be effective in certain situations. The efficacy of these injections may be more dependent on the quality of the injectate, which given their autologous nature, may be dependent on lifestyle choices like exercise, diet, and supplements. The literature describing PRP injections shows that the number and activity of platelets can improve their efficacy. A multitude of lifestyle modifications can affect those factors. Exercise intensity appears to increase platelet count and increases adhesion as well as release of growth factors. Low inflammatory diets increase platelet counts and activity overall. Stress, some supplements, high cholesterol, or processed sugar diets can increase inflammation and potentially decrease platelet counts as well as quality of PRP injectate. Similarly, cell-based therapies can be affected by mesenchymal stromal cell (MSC) number and quality. Cell-based therapy is based upon limiting cellular senescence and increasing replication and differentiation. Exercise may limit senescence and improve replication and differentiation of these cell-based therapies, especially in older adult populations. There are a multitude of supplements that may potentiate these types of injections and patients should discuss the potential benefits and concerns when starting a supplement regimen. Certain foods as well as changes in oxygenation may limit cellular senescence and lower calorie intake may affect MSC viability and function as well. Overall, the current state of literature describes biologic plausibility of how exercise, diet and supplements might affect orthobiologic injection efficacy. Further translational research needs to be completed to describe the effect size and improve recommendations for clinical implementation.

Osteoarthritis (OA) is a common joint disease characterized by pain and functional impairment, which severely impacts the quality of life of middle-aged and elderly individuals. During normal bone development, chondrocyte hypertrophy is a natural physiological process. However, in the progression of OA, chondrocyte hypertrophy becomes one of its key pathological features. Although there is no definitive evidence to date confirming that chondrocyte hypertrophy is the direct cause of OA, substantial experimental data indicate that it plays an important role in the disease's pathogenesis. In this review, we first explore the mechanisms underlying chondrocyte hypertrophy in OA and offer new insights. We then propose strategies for inhibiting chondrocyte hypertrophy from the perspectives of targeting signaling pathways and tissue engineering, ultimately envisioning the future prospects of OA treatment.

Inflammation is a complex host response to harmful infections or injuries, playing both beneficial and detrimental roles in tissue regeneration. Notably, clinical dentinogenesis associated with caries development occurs within an inflammatory environment. Reparative dentinogenesis is closely linked to intense inflammation, which triggers the recruitment and differentiation of dental pulp stem cells (DPSCs) into the dentin lineage. Understanding how inflammatory responses influence DPSCs is essential for elucidating the mechanisms underlying dentin and pulp regeneration. Given the limited data on this process, a broad approach is employed here to gain a deeper understanding of the complex mechanisms involved and to identify downstream signaling targets. This study aims to investigate the role of inflammation and the complement receptor C5L2 in the odontoblastic differentiation of DPSCs and the associated transcriptomic changes using poly-A RNA sequencing (RNA-seq). RNA-seq techniques provide insight into the transcriptome of a cell, offering higher coverage and greater resolution of its dynamic nature. Following inflammatory stimulation, DPSCs exhibit significantly altered gene profiles, including marked upregulation of key odontogenic genes, highlighting the critical role of inflammation in dentinogenesis. We demonstrate that TNFα-treated odontoblast-like differentiating DPSCs, under C5L2 modulation, exhibit significant differential gene expression and transcriptomic changes. The data presented may provide new avenues for experimental approaches to uncover pathways in dentinogenesis by identifying specific transcription factors and gene profiles.

JOURNAL/nrgr/04.03/01300535-202501000-00035/figure1/v/2024-05-14T021156Z/r/image-tiff Our previous study found that rat bone marrow-derived neural crest cells (acting as Schwann cell progenitors) have the potential to promote long-distance nerve repair. Cell-based therapy can enhance peripheral nerve repair and regeneration through paracrine bioactive factors and intercellular communication. Nevertheless, the complex contributions of various types of soluble cytokines and extracellular vesicle cargos to the secretome remain unclear. To investigate the role of the secretome and extracellular vesicles in repairing damaged peripheral nerves, we collected conditioned culture medium from hypoxia-pretreated neural crest cells, and found that it significantly promoted the repair of sensory neurons damaged by oxygen-glucose deprivation. The mRNA expression of trophic factors was highly expressed in hypoxia-pretreated neural crest cells. We performed RNA sequencing and bioinformatics analysis and found that miR-21-5p was enriched in hypoxia-pretreated extracellular vesicles of neural crest cells. Subsequently, to further clarify the role of hypoxia-pretreated neural crest cell extracellular vesicles rich in miR-21-5p in axonal growth and regeneration of sensory neurons, we used a microfluidic axonal dissociation model of sensory neurons in vitro, and found that hypoxia-pretreated neural crest cell extracellular vesicles promoted axonal growth and regeneration of sensory neurons, which was greatly dependent on loaded miR-21-5p. Finally, we constructed a miR-21-5p-loaded neural conduit to repair the sciatic nerve defect in rats and found that the motor and sensory functions of injured rat hind limb, as well as muscle tissue morphology of the hind limbs, were obviously restored. These findings suggest that hypoxia-pretreated neural crest extracellular vesicles are natural nanoparticles rich in miRNA-21-5p. miRNA-21-5p is one of the main contributors to promoting nerve regeneration by the neural crest cell secretome. This helps to explain the mechanism of action of the secretome and extracellular vesicles of neural crest cells in repairing damaged peripheral nerves, and also promotes the application of miR-21-5p in tissue engineering regeneration medicine.

As the number of patients requiring organ transplants continues to rise exponentially, there is a dire need for therapeutics, with repair and regenerative properties, to assist in alleviating this medical crisis. Over the past decade, there has been a shift from conventional stem cell treatments towards the use of the secretome, the protein and factor secretions from cells. These components may possess novel druggable targets and hold the key to profoundly altering the field of regenerative medicine. Despite the progress in this field, clinical translation of secretome-containing products is limited by several challenges including but not limited to ensuring batch-to-batch consistency, the prevention of further heterogeneity, production of sufficient secretome quantities, product registration, good manufacturing practice protocols and the pharmacokinetic/pharmacodynamic profiles of all the components. Despite this, the secretome may hold the key to unlocking the regenerative blockage scientists have encountered for years. This review critically analyses the secretome derived from different cell sources and used in several tissues for tissue regeneration. Furthermore, it provides an overview of the current delivery strategies and the future perspectives for the secretome as a potential therapeutic. The success and possible shortcomings of the secretome are evaluated.

The therapeutic potential of mesenchymal stem cells (MSCs) may be partly attributed to their secretion growth factors, cytokines and chemokines. In various preclinical studies, the use of MSC-conditioned media (CM) has demonstrated promising potential for promoting vascular repair.

To gain a comprehensive understanding of the variations in conditioned media derived from different sources of mesenchymal stem cells (MSCs) including umbilical cord, adipose and bone marrow, we investigated their reparative effects on human umbilical vein endothelial cells (HUVECs) subjected to damage induced by high glucose. Initially, the secreted proteins from the three types of MSCs were assessed using the bicinchoninic acid (BCA) method. Subsequently, we examined the influence of different type of MSC secreted proteins on the proliferation of HUVECs under high glucose conditions. Following this, transwell migration experiments were conducted to evaluate the impact of MSC source on the migration of HUVECs damaged by high glucose. We further compared the effects of adding secreted proteins from the three types of MSCs on the tube formation ability of HUVECs subjected to high glucose damage. Finally, tandem mass tag (TMT) labeling quantitative proteomics was performed to analyze differently expressed proteins in the secreted proteins of three type MSC by using LC-MS/MS.

In this study, we observed a significantly higher secretion of proteins from umbilical cord mesenchymal stem cells (UMSCs) compared to adipose-derived stem cells (ADSCs). Subsequently, we found that the of proliferation HUVECs was significantly improved with supplementing the three MSCs secreted proteins under high glucose medium. Notably, the reparative effects of bone marrow mesenchymal stem cells (BMSCs) and UMSCs were superior to those of ADSCs. Afterwards, UMSCs exhibited the strongest ability to repair cell migration when HUVECs damaged by high glucose. Moreover, all three MSCs' secreted proteins exhibited the ability to enhance tube formation. Importantly, the UMSCs' secretome showed the most pronounced improvement in tube formation, as evidenced by the evaluation of parameters such as the number of nodes, the number of branches, and total length. These findings suggest that the UMSCs' secretome plays a crucial role in biological processes such as vasculature development, cell adhesion, and tissue remodeling. Additionally, the BMSCs' secretome was found to promote vascular development. The results collectively indicate the diverse therapeutic potential of MSC secretomes in influencing various aspects of cellular function and tissue repair.

In conclusion, this study offers a valuable reference for the selection of more suitable sources of mesenchymal stem cells (MSCs) in the treatment of diabetic cardiovascular disease.

Mesenchymal stromal cells (MSCs) are multipotent adult stem cells which possess immunomodulatory and repair capabilities. In this study, we investigated whether MSC therapy could modulate inflammation and lung damage in the lungs of Scnn1b-transgenic mice overexpressing the β-subunit of the epithelial sodium channel (β-ENaC), a model with features of Cystic Fibrosis lung disease. Human bone marrow derived MSC cells were intravenously delivered to mice, prior to collection of bronchoalveolar lavage (BALF) and tissue. BALF analysis revealed a significant reduction in inflammatory cells after MSC administration, with both monocytic cells and neutrophils significantly reduced. Pro-inflammatory cytokines keratinocyte-derived chemokine (KC) and osteopontin were also significantly reduced. Histological tissue analysis revealed a reduction in emphysema in Scnn1b-TG mice treated with MSCs and consistent with these findings, improvements in lung function after MSC therapy were observed. Furthermore, MSCs enhanced Ki67 staining in alveolar cells, which may indicate regeneration of the destroyed parenchyma. Mechanistically, restoration of peroxisome proliferator-activated receptor-γ (PPARγ) expression and its transcriptional program were identified after MSC treatment. Our data demonstrate that MSC therapy can reduce inflammation, damage, and lung function decline in the chronically inflamed lung of Scnn1b-Tg mice, suggesting that MSCs may provide an effective tool in the treatment of muco-obstructive diseases such as cystic fibrosis.

Excess weight during pregnancy is a condition that can affect both mother and fetus, through the maternal-fetal interface, which is constituted by the placenta and umbilical cord. The umbilical vein is responsible for transporting oxygen and nutrients to the fetus, and its proper functioning depends on the integrity of its structure. The remodeling of the umbilical vein represents one of the causes of inadequate transport of nutrients to the fetus, being potentially harmful. This study aims to evaluate whether maternal overweight alters the structural characteristics of the umbilical vein.

Umbilical cords were collected from eutrophic and overweight pregnant women and were processed according to histological routine. We analyzed morphometry parameters, collagen and elastin fibers deposition, glycosaminoglycan level, and cell proliferation.

Veins from overweight pregnant women were found to have greater total area, wall area, wall thickness, and diameter. There was higher collagen labeling in the perivascular region of the overweight group and a higher amount of type III collagen in the vascular smooth muscle. The proliferation of muscle and perivascular cells was higher in overweight pregnant women. A positive, although weak, correlation was observed between BMI and vessel thickness and with type III collagen deposition in vascular smooth muscle.

With this study, we show that being overweight can structurally alter the umbilical vein, causing vascular remodeling of the vessel, through hypertrophy and hyperplasia.

Background: Stem cells are capable of self-renewal and differentiation into various specialized cells, making them a potential therapeutic option in regenerative medicine. This study establishes a comprehensive methodology for isolating, culturing, and characterizing rat hair follicle stem cells. Methods and Results: Hair follicles were harvested from Sprague-Dawley rats and subjected to two different isolation techniques. Immunohistochemical analysis and real-time PCR confirm the expression of specific surface markers and genes, validating the cells' identity. Growth kinetics, colony formation units (CFU), and tri-differentiation capacity were also assessed. Additionally, the cells' secretome was analyzed, regarding its content in biofactors with wound healing properties. Conclusions: These findings highlight the potential of these cells as a valuable cell source for skin regeneration applications. They contribute to advancing our understanding of stem cell applications in regenerative medicine and hold promise for therapeutic interventions in various clinical contexts, aligning with broader research on the diverse capabilities of hair follicle stem cells.

Autoimmune diseases represent a severe personal and healthcare problem that seeks novel therapeutic solutions. Mesenchymal stem cells (MSCs) are multipotent cells with interesting cell biology and promising therapeutic potential. The immunoregulatory effects of secretory factors produced by umbilical cord mesenchymal stem cells (UC-MSCs) were assessed on B lymphocytes from 17 patients with systemic lupus erythematosus (SLE), as defined by the 2019 European Alliance of Associations for Rheumatology (EULAR)/American College of Rheumatology (ACR) classification criteria for SLE, and 10 healthy volunteers (HVs). Peripheral blood mononuclear cells (PBMCs) from patients and HVs were cultured in a UC-MSC-conditioned medium (UC-MSCcm) and a control medium. Flow cytometry was used to detect the surface expression of CD80, CD86, BR3, CD40, PD-1, and HLA-DR on CD19+ B cells and assess the percentage of B cells in early and late apoptosis. An enzyme-linked immunosorbent assay (ELISA) quantified the production of BAFF, IDO, and PGE2 in PBMCs and UC-MSCs. Under UC-MSCcm influence, the percentage and mean fluorescence intensity (MFI) of CD19+BR3+ cells were reduced in both SLE patients and HVs. Regarding the effects of the MSC secretome on B cells in lupus patients, we observed a decrease in CD40 MFI and a reduced percentage of CD19+PD-1+ and CD19+HLA-DR+ cells. In contrast, in the B cells of healthy participants, we found an increased percentage of CD19+CD80+ cells and decreased CD80 MFI, along with a decrease in CD40 MFI and the percentage of CD19+PD-1+ cells. The UC-MSCcm had a minimal effect on B-cell apoptosis. The incubation of patients' PBMCs with the UC-MSCcm increased PGE2 levels compared to the control medium. This study provides new insights into the impact of the MSC secretome on the key molecules involved in B-cell activation and antigen presentation and survival, potentially guiding the development of future SLE treatments.

The aim of this study was to assess the safety and efficacy of human umbilical cord mesenchymal stromal cells (hUC-MSCs) patch used as an adjuvant therapy in fetal myelomeningocele (MMC) surgery in the ovine model.

hUC-MSCs were isolated from human umbilical cords (UC) using the explant method, cultured and characterized. hUC-MSCs were then embedded in a fibrin patch. MMC were surgically created at 75 days of gestation and repaired at 89 days of gestation in sheep fetuses. Two groups were compared: the hUC-MSCs group in which MMC was repaired using a cellular patch and the control group, in which MMC was repaired using an acellular patch. Safety was evaluated by clinical ewes' monitoring during gestation, and clinical and histological examinations of lambs after birth. Efficacy was assessed by clinical neurological evaluation at 2 and 24 h of life using the sheep locomotor rating scale and by histological analyses.

Among the 17 operated lambs, nine were born alive: six in the hUC-MSCs group and three in the control group. Overall fetal loss was 47% (8/17) without differences between the two groups. No fever was reported in ewes. No tumors were detected in clinical and histological examinations in the lambs. At 24 h of life, mean Sheep Locomotor Rating score was higher in the hUC-MSCs group than in the control group: 15.0 versus 2.0 (p = 0.07). Histological analyses showed a higher large neurons density in the hUC-MSCs group in comparison with the control group: 9.9 versus 6.3/mm2 of gray matter (p = 0.04). Lambs in the hUC-MSCs group had lower fibrosis around the spinal cord and at the level of the MMC scar: 70.9 versus 253.7 μm (p = 0.10) and 691.3 versus 1684.4 μm (p = 0,18), respectively.

Ovine fetal repair of MMC using human UC-MSCs seems to be an effective and safe procedure.

Myocardial infarction (MI) is a leading cause of heart failure, disability and mortality worldwide. In this study, the effects of intramyocardial injection of human platelet lysate (HPL), bone marrow mesenchymal stem cells pretreated with HPL (PMSCs), and PMSC lysate (lys), alone and in combination were investigated on MI-induced by LAD ligation in male Wistar rats. The experiment was carried out on sham, vehicle (Veh), HPL, PMSCs, PMSC lysate (PMSC lys), HPL + PMSCs, and HPL + PMSC lys groups. SBP, DBP, and ± dp/dt max were monitored by the PowerLab physiograph. The MSC characteristics and CD31, NKX2.5, and cardiac troponin I (cTnI) contents were determined by flow cytometry, immunohistochemistry, and immunofluorescence, respectively. SBP, DBP, and ± dp/dt max that decreased in the MI group were recovered by HPL, PMSC, PMSC lys, HPL + PMSC, and HPL + PMSC lys treatments. CD31 density was higher in all treated groups compared to the Veh group. CD31 density in the HPL + PMSCs and HPL + PMSC lys groups was higher than in the PMSCs group. The number of Dil+/NKX2.5 + and Dil+/cTnI + cells was higher in the HPL + PMSCs group compared to the PMSCs group. The HPL and PMSCs mitigates heart injuries and cardiac dysfunction after MI. HPL provides an appropriate environment for cardiomyocyte differentiation from PMSCs.

Globally, prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is increasing, and there is an urgent need to develop innovative therapies that promote liver regeneration following hepatectomy for this disease. Surgical excision is a key therapeutic approach with curative potential for liver tumors. However, hepatic steatosis can lead to delayed liver regeneration and higher post-operative complication risk. Mesenchymal stem cells-conditioned medium (MSC-CM) is considered a rich source of paracrine factors that can repair tissues and restore function of damaged organs. Meanwhile, hydrogels have been widely recognized to load MSC secretome and achieve sustained release. This study aimed to evaluate the therapeutic effect of hydrogel-encapsulated MSC-CM on liver regeneration following partial hepatectomy (PHx) in a rodent model of diet-induced hepatic steatosis.

Male Lewis rats were fed with a methionine and choline-deficient diet. After 3 weeks of feeding, PHx was performed and rats were randomly allocated into two groups that received hydrogel-encapsulated MSC-CM or vehicle via the intra-mesenteric space of the superior mesenteric vein (SMV).

The regeneration of the remnant liver at 30 and 168 h after PHx was significantly accelerated, and the expressions of proliferating cell nuclear antigen were significantly enhanced in the MSC-CM group. MSC-CM treatment significantly increased hepatic ATP and β-hydroxybutyrate content at 168 h after PHx, indicating that MSC-CM fosters regeneration not only in volume but also in functionality. The number of each TUNEL- and cleaved caspase-3 positive nuclei in hepatocytes at 9 h after PHx were significantly decreased in the MSC-CM group, suggesting that MSC-CM suppressed apoptosis. MSC-CM increased serum immunoregulatory cytokine interleukin-10 and interleukin-13 at 30 h after PHx. Additionally, mitotic figures and cyclin D1 expression decreased and hepatocyte size increased in the MSC-CM group, implying that this mode of regeneration was mainly through cell hypertrophy rather than cell division.

MSC-CM represents a novel therapeutic approach for patients with MASLD requiring PHx.

As research into preclinical rheumatoid arthritis (pre-RA) has advanced, a growing body of evidence suggests that abnormalities in RA-affected joint cartilage precede the onset of arthritis. Thus, early prevention and treatment strategies are imperative. In this study, we aimed to explore the protective effects of mesenchymal stem cell (MSC)-derived microvesicles (MVs) on cartilage degradation in a collagen-induced arthritis (CIA) mouse model.

A CIA mouse model was established to observe early pathological changes in cartilage (days 21-25) through histological and radiological examinations. On day 22, MSCs-MVs were intravenously injected into the mice with CIA. Radiological, histological, and flow cytometric examinations were conducted to observe inflammation and cartilage changes in these mice compared to the mice with CIA and the control mice. In vitro, chondrocytes were cultured with inflammatory factors such as IL-1β and TNFα to simulate inflammatory damage to cartilage. After the addition of MVs, changes in inflammatory levels and collagen expression were measured via Western blotting, immunofluorescence, enzyme-linked immunosorbent assays (ELISAs), and quantitative PCR to determine the role of MVs in maintaining chondrocytes.

MSC-MVs expressed vesicular membrane proteins (CD63 and Annexin V) and surface markers characteristic of MSCs (CD44, CD73, CD90, and CD105). In the early stages of CIA in mice, a notable decrease in collagen content was observed in the joint cartilage. In mice with CIA, injection of MSCs-MVs resulted in a significant reduction in the peripheral blood levels of IL-1β, TNFα, and IL-6, along with a decrease in the ratio of proinflammatory T and B cells. Additionally, MSC-MVs downregulated the expression of IL-1β, TNFα, MMP-13, and ADAMTS-5 in cartilage while maintaining the stability of type I and type II collagen. These MVs also attenuated the destruction of cartilage, which was evident on imaging. In vitro experiments demonstrated that MSC-MVs effectively suppressed the secretion of the inflammatory factors IL-1β, TNFα, and IL-6 in stimulated peripheral blood mononuclear cells (PBMCs).

MSCs-MVs can inhibit the decomposition of the inflammation-induced cartilage matrix by regulating immune cell inflammatory factors to attenuate cartilage destruction. MSC-MVs are promising effective treatments for the early stages of RA.

Spinocerebellar ataxia (SCA) is a heterogeneous disorder characterized by impaired balance and coordination caused by cerebellar dysfunction. The absence of treatments approved by the U.S. Food and Drug Administration for SCA has driven the investigation of alternative therapeutic strategies, including stem cell therapy. Mesenchymal stem cells (MSCs), known for their multipotent capabilities, have demonstrated significant potential in treating SCA. This review examines how MSCs may promote neuronal growth, enhance synaptic connectivity, and modulate brain inflammation. Recent findings from preclinical and clinical studies are also reviewed, emphasizing the promise of MSC therapy in addressing the unmet needs of SCA patients. Furthermore, ongoing clinical trials and future directions are proposed to address the limitations of the current approaches.

Regenerative therapy based on stem cells have been developed, focusing on either stem cell or secretome delivery. Most marketed cellular and gene therapy products are available as injectable dosage forms, leading to several limitations requiring alternative routes, such as the intradermal route. Microneedles, capable of penetratingthe stratum corneumbarrier, offer a potential alternative for intradermal delivery. This present study aimed to develop double-layer dissolving microneedles (DMN) for the delivery of freeze-dried mesenchymal stem cell secretome. DMNs were fabricated using a two-step casting method and composed of two polymer combinations: poly(vinyl pyrrolidone) (PVP) with poly(vinyl alcohol) (PVA) or PVP with sodium hyaluronate (SH). The manufactured DMNs underwent assessments for morphology, mechanical strength, in skin dissolution, protein content, in vitro permeation, in vivo skin irritation, and physical stability. Based on evaluations of morphology and mechanical strength, two formulas (F5 and F12) met acceptance criteria. Evaluation of protein content revealed that F12 (PVP-SH combination) had a higher protein content than F5 (PVP-PVA combination), 99.02 ± 3.24 μg and 78.36 ± 3.75 μg respectively. In vitro permeation studies showed that F5 delivered secretome protein by 100.84 ± 0.88%, while F12 delivered 99.63 ± 9.21% in 24 h. After four days of observation onSprague-Dawleyrat's skin, no signs of irritation, such as oedema and redness, was observed after applying both formulations. The safety of using PVP-PVA and PVP-SH combinations as excipients for DMN secretome delivery has been confirmed, promising significant advancements in biotherapeutic development in the future.

Osteoarthritis (OA) is a degenerative joint disease characterized by cartilage degradation and inflammation. This study investigates the therapeutic potential of secretome derived from adipose tissue mesenchymal stem cells (ASCs) in mitigating inflammation and promoting cartilage repair in an in vitro model of OA. Our in vitro model comprised chondrocytes inflamed with TNF. To assess the therapeutic potential of secretome, inflamed chondrocytes were treated with it and concentrations of pro-inflammatory cytokines, metalloproteinases (MMPs) and extracellular matrix markers were measured. In addition, secretome-treated chondrocytes were subject to a microarray analysis to determine which genes were upregulated and which were downregulated. Treating TNF-inflamed chondrocytes with secretome in vitro inhibits the NF-κB pathway, thereby mediating anti-inflammatory and anti-catabolic effects. Additional protective effects of secretome on cartilage are revealed in the inhibition of hypertrophy markers such as RUNX2 and COL10A1, increased production of COL2A1 and ACAN and upregulation of SOX9. These findings suggest that ASC-derived secretome can effectively reduce inflammation, promote cartilage repair, and maintain chondrocyte phenotype. This study highlights the potential of ASC-derived secretome as a novel, non-cell-based therapeutic approach for OA, offering a promising alternative to current treatments by targeting inflammation and cartilage repair mechanisms.

The lifelong administration of immunosuppressants remains the largest drawback in vascularized composite allotransplantation (VCA). Therefore, developing alternative strategies to minimize the long-term use of immunosuppressive agents is crucial. This study investigated whether full-spectrum bright light therapy (FBLT) combined with short-term immunosuppressant therapy could prolong VCA survival in a rodent hindlimb model.

Hindlimb allotransplantation was conducted from Brown-Norway to Lewis rats, and the rats were divided into 4 groups. Group 1 did not receive treatment as a rejection control. Group 2 received FBLT alone. Group 3 was treated with short-term antilymphocyte serum (ALS) and cyclosporine A (CsA). Group 4 was administered short-term ALS/CsA combined with FBLT for 8 weeks. Peripheral blood and transplanted tissues were collected for analysis.

The results revealed median survival time of FBLT alone (group 2) did not increase allograft survival compared with the control (group 1). However, in group 4, FBLT combined with short-term ALS/CsA, median composite tissue allograft survival time (266 days) was significantly prolonged compared with groups 1 (11 days), 2 (10 days), and 3 (41 days) ( P < 0.01). Group 4 also showed a significant increase in regulatory T cells ( P = 0.04) and transforming growth factor-β1 levels ( P = 0.02), and a trend toward a decrease in interleukin-1β levels ( P = 0.03) at 16 weeks after transplantation as compared with control (group 1).

FBLT combined with short-term immunosuppressants prolonged allotransplant survival by modulating T-cell regulatory functions and antiinflammatory cytokine expression. This approach could be a potential strategy to increase VCA survival.

Full-spectrum light therapy could be a potential strategy to increase vascularized composite allotransplant survival.

Wound healing is an orderly sequence of events restoring the integrity of the damaged tissue. It consists of inflammatory, proliferation, and remodeling phases. The objective of the current study was to investigate the effect of local transplantation of cultured macrophage loaded with mesenchymal stem cell/macrophage culture supernatants on wound healing. Sixty-four healthy adult male Wistar rats were randomized into 4 groups of sixteen animals each: 1) SHAM group. 2) MAC-MSC/SN group: One-milliliter application of a mixture comprising mesenchymal stem cell and macrophage culture supernatants in a 1:1 ratio was administered locally to the wound bed. 3) MAC group: Local transplantation of macrophage cells cultured in the wound bed. 4) MAC + MAC-MSC/SN group: Local transplantation of cultured macrophage in combination with mesenchymal stem cell/ macrophage culture supernatants in the wound bed. An incisional wound model was used for biomechanical studies, while an excisional wound model was used for biochemical, histopathological, and planimetric assessments. The wound area was significantly reduced in the MAC + MAC-MSC/SN group compared to other groups (P < 0.05). Biomechanical measurements from the MAC + MAC-MSC/SN group were significantly higher compared to other experimental groups (P < 0.05). Biochemical and quantitative histopathological analyses revealed a significant difference between MAC + MAC-MSC/SN and other groups (P < 0.05). MAC + MAC-MSC/SN showed the potential to improve wound healing significantly. This appears to work by angiogenesis stimulation, fibroblast proliferation, inflammation reduction, and granulation tissue formation during the initial stages of the healing process. This accelerated healing leads to earlier wound area reduction and enhanced tensile strength of the damaged area due to the reorganization of granulation tissue and collagen fibers.

This review explores the regenerative potential of key progenitor cell types and therapeutic strategies to improve healing of complex fractures and bone defects. We define, summarize, and discuss the differentiation potential of totipotent, pluripotent, and multipotent stem cells, emphasizing the advantages and shortcomings of cell therapy for bone repair and regeneration. The fundamental role of mesenchymal stem cells is highlighted due to their multipotency to differentiate into the key lineage cells including osteoblasts, osteocytes, and chondrocytes, which are crucial for bone formation and remodeling. Hematopoietic stem cells (HSCs) also play a significant role; immune cells such as macrophages and T-cells modulate inflammation and tissue repair. Osteoclasts are multinucleated cells that are important to bone remodeling. Vascular progenitor (VP) cells are critical to oxygen and nutrient supply. The dynamic interplay among these lineages and their microenvironment is essential for effective bone restoration. Therapies involving cells that are more than "minimally manipulated" are controversial and include embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). ESCs, derived from early-stage embryos, possess pluripotent capabilities and have shown promise in preclinical studies for bone healing. iPSCs, reprogrammed from somatic cells, offer personalized medicine applications and can differentiate into various tissue-specific cell lines. Minimally manipulative cell therapy approaches such as the use of bone marrow aspirate concentrate (BMAC), exosomes, and various biomaterials for local delivery are explored for their effectiveness in bone regeneration. BMAC, which contains mostly immune cells but few mesenchymal and VPs, probably improves bone healing by facilitating paracrine-mediated intercellular communication. Exosome isolation harnesses the biological signals and cellular by-products that are a primary source for cell crosstalk and activation. Safe, efficacious, and cost-effective strategies to enhance bone healing using novel cellular therapies are part of a changing paradigm to modulate the inflammatory, repair, and regenerative pathways to achieve earlier more robust tissue healing and improved physical function. Impact Statement Stem cell therapy holds immense potential for bone healing due to its ability to regenerate damaged tissue. Nonmanipulated bone marrow aspirate contains mesenchymal stem cells that promote bone repair and reduce healing time. Induced pluripotent stem cells offer the advantage of creating patient-specific cells that can differentiate into osteoblasts, aiding in bone regeneration. Other delivery methods, such as scaffold-based techniques, enhance stem cell integration and function. Collectively, these approaches can improve treatment outcomes, reduce recovery periods, and advance our understanding of bone healing mechanisms, making them pivotal in orthopedic research and regenerative medicine.

Although treatment for multiple sclerosis (MS) has undergone a revolution in the last decades, at least two important barriers remain: alleviation of innate inflammation driving disease progression and promotion of remyelination and neural regeneration. Mesenchymal stem cells (MSCs) possess immunomodulatory properties and promote remyelination in murine MS models. The main therapeutic mechanism has, however, been attributed to their potent paracrine capacity, and not to in vivo tissue implantation. Studies have demonstrated that exosomes released as part of the cells' secretome effectively encapsulate the beneficial properties of MSCs. These membrane-enclosed nanoparticles contain a variety of proteins and nucleic acids and serve as mediators of intercellular communication. In vitro studies have demonstrated that exosomes from MSCs modulate activated microglia from an inflammatory to an anti-inflammatory phenotype and thereby dampen the innate inflammation. Rodent studies have also demonstrated potent immunomodulation and remyelination with improved outcomes following exosome administration. Thus, exosomes from MSCs may represent a potential cell-free treatment modality to prevent disease progression and promote remyelination in MS. In this narrative review, we summarize the current knowledge of exosomes from MSCs as a potential treatment for MS and discuss the remaining issues before successful translation into clinical trials.

This detailed review describes innovative strategies and current products for gene and cell therapy at different stages of research and development to treat recessive dystrophic epidermolysis bullosa (RDEB) which is associated with the functional deficiency of collagen type VII alpha 1 (C7) caused by defects in the COL7A1 gene. The use of allogenic mesenchymal stem/stromal cells, which can be injected intradermally and intravenously, appears to be the most promising approach in the field of RDEB cell therapy. Injections of genetically modified autologous dermal fibroblasts are also worth mentioning under this framework. The most common methods of RDEB gene therapy are gene replacement using viral vectors and gene editing using programmable nucleases. Ex vivo epidermal transplants (ETs) based on autologous keratinocytes (Ks) have been developed using gene therapy methods; one such ET successively passed phase III clinical trials. Products based on the use of two-layer transplants have also been developed with both types of skin cells producing C7. Gene products have also been developed for local use. To date, significant progress has been achieved in the development of efficient biomedical products to treat RDEB, one of the most severe hereditary diseases.

Bronchopulmonary dysplasia (BPD) is the most common lung complication of prematurity. Despite extensive research, our understanding of its pathophysiology remains limited, as reflected by the stable prevalence of BPD. Prematurity is the primary risk factor for BPD, with oxidative stress (OS) and inflammation playing significant roles and being closely linked to premature birth. Understanding the interplay and temporal relationship between OS and inflammation is crucial for developing new treatments for BPD. Animal studies suggest that OS and inflammation can exacerbate each other. Clinical trials focusing solely on antioxidants or anti-inflammatory therapies have been unsuccessful. In contrast, vitamin A and caffeine, with antioxidant and anti-inflammatory properties, have shown some efficacy, reducing BPD by about 10%. However, more than one-third of very preterm infants still suffer from BPD. New therapeutic agents are needed. A novel tripeptide, N-acetyl-lysyltyrosylcysteine amide (KYC), is a reversible myeloperoxidase inhibitor and a systems pharmacology agent. It reduces BPD severity by inhibiting MPO, enhancing antioxidative proteins, and alleviating endoplasmic reticulum stress and cellular senescence in a hyperoxia rat model. KYC represents a promising new approach to BPD treatment.

Diabetes represents a widely acknowledged global public health concern. Diabetic foot ulcer (DFU) stands as one of the most severe complications of diabetes, its occurrence imposing a substantial economic burden on patients, profoundly impacting their quality of life. Despite the deepening comprehension regarding the pathophysiology and cellular as well as molecular responses of DFU, the current therapeutic arsenal falls short of efficacy, failing to offer a comprehensive remedy for deep-seated chronic wounds and microvascular occlusions. Conventional treatments merely afford symptomatic alleviation or retard the disease's advancement, devoid of the capacity to effectuate further restitution of compromised vasculature and nerves. An escalating body of research underscores the prominence of mesenchymal stem cells (MSCs) owing to their paracrine attributes and anti-inflammatory prowess, rendering them a focal point in the realm of chronic wound healing. Presently, MSCs have been validated as a highly promising cellular therapeutic approach for DFU, capable of effectuating cellular repair, epithelialization, granulation tissue formation, and neovascularization by means of targeted differentiation, angiogenesis promotion, immunomodulation, and paracrine activities, thereby fostering wound healing. The secretome of MSCs comprises cytokines, growth factors, chemokines, alongside exosomes harboring mRNA, proteins, and microRNAs, possessing immunomodulatory and regenerative properties. The present study provides a systematic exposition on the etiology of DFU and elucidates the intricate molecular mechanisms and diverse functionalities of MSCs in the context of DFU treatment, thereby furnishing pioneering perspectives aimed at harnessing the therapeutic potential of MSCs for DFU management and advancing wound healing processes.

Over the past two decades, mesenchymal stem/stromal cell (MSC) therapy has made substantial strides, transitioning from experimental clinical applications to commercial products. MSC therapies hold considerable promise for treating refractory and critical conditions such as acute graft-versus-host disease, amyotrophic lateral sclerosis, and acute respiratory distress syndrome. Despite recent successes in clinical and commercial applications, MSC therapy still faces challenges when used as a commercial product. Current detection methods have limitations, leaving the dynamic biodistribution, persistence in injured tissues, and ultimate fate of MSCs in patients unclear. Clarifying the relationship between the pharmacokinetic characteristics of MSCs and their therapeutic effects is crucial for patient stratification and the formulation of precise therapeutic regimens. Moreover, the development of advanced imaging and tracking technologies is essential to address these clinical challenges. This review provides a comprehensive analysis of the kinetic properties, key regulatory molecules, different fates, and detection methods relevant to MSCs and discusses concerns in evaluating MSC druggability from the perspective of integrating pharmacokinetics and efficacy. A better understanding of these challenges could improve MSC clinical efficacy and speed up the introduction of MSC therapy products to the market.

Diabetic foot ulcers (DFUs) are chronic wounds and one of the most common complications of diabetes, imposing significant physical and mental burdens on patients due to their poor prognosis and treatment efficacy. Adipose-derived stem cells (ADSCs) have been proven to promote wound healing, with studies increasingly attributing these beneficial effects to their paracrine actions. Consequently, research on ADSC secretome as a novel and promising alternative for DFU treatment has been extensively conducted. This article provides a comprehensive review of the mechanisms underlying refractory DFU wounds, the secretome of ADSCs, and its role in promoting wound healing in diabetes foot ulcers. And the review aims to provide reliable evidence for the clinical application of ADSC secretome in the treatment of refractory DFU wounds.

Photobiomodulation (PBM), the use of biocompatible tissue-penetrating light to interact with intracellular chromophores to modulate the fates of cells and tissues, has emerged as a promising non-invasive approach to enhancing tissue regeneration. Unlike photodynamic or photothermal therapies that require the use of photothermal agents or photosensitizers, PBM treatment does not need external agents. With its non-harmful nature, PBM has demonstrated efficacy in enhancing molecular secretions and cellular functions relevant to tissue regeneration. The utilization of low-level light from various sources in PBM targets cytochrome c oxidase, leading to increased synthesis of adenosine triphosphate, induction of growth factor secretion, activation of signaling pathways, and promotion of direct or indirect gene expression. When integrated with stem cell populations, bioactive molecules or nanoparticles, or biomaterial scaffolds, PBM proves effective in significantly improving tissue regeneration. This review consolidates findings from in vitro, in vivo, and human clinical outcomes of both PBM alone and PBM-combined therapies in tissue regeneration applications. It encompasses the background of PBM invention, optimization of PBM parameters (such as wavelength, irradiation, and exposure time), and understanding of the mechanisms for PBM to enhance tissue regeneration. The comprehensive exploration concludes with insights into future directions and perspectives for the tissue regeneration applications of PBM.