Therapeutic potential of conditioned medium obtained from deferoxamine preconditioned umbilical cord mesenchymal stem cells on diabetic nephropathy model

Brain-Derived Neurotrophic Factor-Loaded Low-Temperature-Sensitive liposomes as a drug delivery system for repairing podocyte damage

Podocytes, cells of the glomerular filtration barrier, play a crucial role in kidney diseases and are gaining attention as potential targets for new therapies. Brain-Derived Neurotrophic Factor (BDNF) has shown promising results in repairing podocyte damage, but its efficacy via parenteral administration is limited by a short half-life. Low temperature sensitive liposomes (LTSL) are a promising tool for targeted BDNF delivery, preserving its activity after encapsulation. This study aimed to improve LTSL design for efficient BDNF encapsulation and targeted release to podocytes, while maintaining stability and biological activity, and exploiting the conjugation of targeting peptides. While cyclic RGD (cRGD) was used for targeting endothelial cells in vitro, a homing peptide (HITSLLS) was conjugated for more specific uptake by glomerular endothelial cells in vivo. BDNF-loaded LTSL successfully repaired cytoskeleton damage in podocytes and reduced albumin permeability in a glomerular co-culture model. cRGD conjugation enhanced endothelial cell targeting and uptake, highlighting an improved therapeutic effect when BDNF release was induced by thermoresponsive liposomal degradation. In vivo, targeted LTSL showed evidence of accumulation in the kidneys, and their BDNF delivery decreased proteinuria and ameliorated kidney histology. These findings highlight the potential of BDNF-LTSL formulations in restoring podocyte function and treating glomerular diseases.

Therapeutic potential: The role of mesenchymal stem cells from diverse sources and their derived exosomes in diabetic nephropathy

Diabetic nephropathy (DN) is one of the most common microvascular complications in diabetic patients, with its incidence continuously increasing in recent years. DN causes renal tissue damage and functional decline, expedites the aging process of the kidneys, and may ultimately progress leading to end-stage renal disease, severely impacting the patient's quality of life and prognosis. Mesenchymal stem cells (MSCs) are highly valued for their multipotent differentiation, paracrine functions, immunomodulatory effects, and capacity for tissue repair. Particularly, exosomes (Exo) derived from MSCs (MSCs-Exo) are rich in bioactive molecules and facilitate intercellular communication, participating in various physiological and pathological processes. MSCs and MSCs-Exo, in particular, have been demonstrated to have therapeutic effects in DN treatment research by encouraging tissue repair, fibrosis inhibition, and inflammation reduction. Research has shown that MSCs and MSCs-Exo have therapeutic effects in DN treatment by promoting tissue repair, inhibiting fibrosis, and reducing inflammation. Recent studies underscore the potential of MSCs and MSCs-Exo, highlighting their broad applicability in DN treatment. This review aims to provide a comprehensive summary of the scientific developments in treating DN using MSCs and MSCs-Exo from diverse sources, while also exploring their future therapeutic possibilities in detail.

Mesenchymal stem cell secretome for regenerative medicine: Where do we stand?

BACKGROUND

Mesenchymal stem cell (MSC)-based therapies have yielded beneficial effects in a broad range of preclinical models and clinical trials for human diseases. In the context of MSC transplantation, it is widely recognized that the main mechanism for the regenerative potential of MSCs is not their differentiation, with in vivo data revealing transient and low engraftment rates. Instead, MSCs therapeutic effects are mainly attributed to its secretome, i.e., paracrine factors secreted by these cells, further offering a more attractive and innovative approach due to the effectiveness and safety of a cell-free product.

AIM OF REVIEW

In this review, we will discuss the potential benefits of MSC-derived secretome in regenerative medicine with particular focus on respiratory, hepatic, and neurological diseases. Both free and vesicular factors of MSC secretome will be detailed. We will also address novel potential strategies capable of improving their healing potential, namely by delivering important regenerative molecules according to specific diseases and tissue needs, as well as non-clinical and clinical studies that allow us to dissect their mechanisms of action.

KEY SCIENTIFIC CONCEPTS OF REVIEW

MSC-derived secretome includes both soluble and non-soluble factors, organized in extracellular vesicles (EVs). Importantly, besides depending on the cell origin, the characteristics and therapeutic potential of MSC secretome is deeply influenced by external stimuli, highlighting the possibility of optimizing their characteristics through preconditioning approaches. Nevertheless, the clarity around their mechanisms of action remains ambiguous, whereas the need for standardized procedures for the successful translation of those products to the clinics urges.

Comparative analysis of effects of conditioned mediums obtained from 2D or 3D cultured mesenchymal stem cells on kidney functions of diabetic rats: Early intervention could potentiate transdifferentiation of parietal epithelial cell into podocyte precursors

AIM

The secretome of mesenchymal stem cells (MSCs) could be a potential therapeutic intervention for diabetes and associated complications like nephropathy. This study aims to evaluate the effects of conditioned mediums (CMs) collected from umbilical cord-derived MSCs incubated under 2-dimensional (2D) or 3D culture conditions on kidney functions of rats with type-I diabetes (T1D).

MAIN METHODS

Sprague-Dawley rats were treated with 20 mg/kg streptozocin for 5 consecutive days to induce T1D, and 12 doses of CMs were applied intraperitoneally for 4 weeks. The therapeutic effects of CMs were comparatively investigated by biochemical, physical, histopathological, and immunohistochemical analysis.

KEY FINDINGS

3D-CM had significantly higher total protein concentration than the 2D-CM Albumin/creatinine ratios of both treatment groups were significantly improved in comparison to diabetes. Light microscopic evaluations showed that glomerular and cortical tubular damages were significantly ameliorated in only the 3D-CM applied group compared to the diabetes group, which were correlated with transmission electron microscopic observations. The nephrin and synaptopodin expressions increased in both treatment groups compared to diabetes. The WT1, Ki-67, and active caspase-3 expressions in glomeruli and parietal layers of the treatment groups suggest that both types of CMs suppress apoptosis and promote possible parietal epithelial cells' (PECs') transdifferentiation towards podocyte precursor cells by switching on WT1 expression in parietal layer rather than inducing new cell proliferation.

SIGNIFICANCE

3D-CM was found to be more effective in improving kidney functions than 2D-CM by ameliorating glomerular damage through the possible mechanism of transdifferentiation of PECs into podocyte precursors and suppressing glomerular apoptosis.

Preemptive administration of mesenchymal stem cells-derived conditioned medium can attenuate the development of neuropathic pain in rats via downregulation of proinflammatory cytokines

Neuropathic pain (NP) is a chronic condition characterized by persistent pain following nerve injury. It is a challenging clinical problem to manage due to limited treatment options. Mesenchymal stem cells (MSCs)-derived conditioned medium (CM) is a cell-free product that contains the secretome of MSCs and has been shown to have therapeutic potential in various inflammatory and degenerative disorders. Several animal studies have examined the antinociceptive effects of MSCs-CM on established neuropathic pain, but none have investigated the early prevention of neuropathic pain using MSCs-CM. Therefore, in this study, we tested whether preemptive administration of MSCs-CM could attenuate the development of NP in rats. To this end, NP was induced in Wistar rats using a chronic constriction injury (CCI) model (day 0), and then the animals were divided into four groups: Sham, CCI, CCI-Dulbecco's Modified Eagle Medium (DMEM), and CCI-CM. The CCI-CM group received 1 ml intraperitoneal administration of MSCs-CM on days - 1, 1, and 2, while the Sham, CCI, and CCI-DMEM groups received vehicle only (normal saline or DMEM). Mechanical withdrawal threshold and thermal withdrawal latency were assessed to evaluate pain sensitivities. In addition, the expression levels of proinflammatory cytokines (TNF-α and IL-1β) in the spinal cord tissues were measured using quantitative real-time PCR (qRT-PCR). The results demonstrated that preemptive treatment with MSCs-CM can significantly attenuate the development of NP, as evidenced by improved mechanical withdrawal threshold and thermal withdrawal latency in the CCI-CM group compared to the CCI and CCI-DMEM groups. Furthermore, the relative gene expression of proinflammatory cytokines TNF-α and IL-1β were significantly decreased in the spinal cord tissues of the CCI-CM group compared to the control groups. These findings suggest that preemptive administration of MSCs-CM can attenuate the development of NP in rats, partly due to the downregulation of proinflammatory cytokines.

Preconditioning of human umbilical cord mesenchymal stem cells with deferoxamine potentiates the capacity of the secretome released from the cells and promotes immunomodulation and beta cell regeneration in a rat model of type 1 diabetes

This study aimed to examine the effects of the secretome released by human umbilical cord-mesenchymal stem cells (MSC) as a result of preconditioning with deferoxamine (DFX), a hypoxia mimetic agent, on type 1 diabetes (T1D), by comparing it with the secretome produced by untreated MSCs. Initially, the levels of total protein, IL4, IL10, IL17, and IFNγ in the conditioned medium (CM) obtained from MSCs subjected to preconditioning with 150 µM DFX (DFX-CM) were analyzed in comparison to CM derived from untreated MSCs (N-CM). Subsequently, the CMs were administered to rats with T1D within a specific treatment plan. Following the sacrification, immunomodulation was evaluated by measuring serum cytokine levels and assessing the regulatory T cell (Treg) ratio in spleen mononuclear cells. Additionally, β-cell mass was determined in the islets by immunohistochemical labeling of NK6 Homeobox 1 (Nkx6.1), Pancreatic duodenal homeobox-1 (Pdx1), and insulin antibodies in pancreatic sections. In vitro findings indicated that the secretome levels of MSCs were enhanced by preconditioning with DFX. In vivo, the use of DFX-CM significantly increased the Treg population, and accordingly, the level of inflammatory cytokines decreased. In β-cell marker labeling, D + DFX-CM showed significantly increased PDX1 and insulin immunoreactivity. In conclusion, while the factors released by MSCs without external stimulation had limited therapeutic effects, substantial improvements in immunomodulation and β-cell regeneration were seen with DFX-preconditioned cell-derived CM.

Effects of conditioned media derived from human Wharton's jelly mesenchymal stem cells on diabetic nephropathy and hepatopathy via modulating TGF-β and apelin signaling pathways in male rats

BACKGROUND

Diabetic nephropathy and hepatopathy are health problems described by specific renal and hepatic structure and function disturbances. The protective effects of the stem cell secretome have been shown in several kidney and liver diseases. The current study aims to evaluate the capability of conditioned media derived from human Wharton's jelly mesenchymal stem cells (hWJ-MSCs-CM) to alleviate diabetic complications.

METHODS

Twenty Sprague Dawley rats were made diabetic through injection of STZ (60 mg/kg, i.p.). At week 8, diabetic rats were divided into two groups: treated [DM + hWJ-MSCs-CM (500 µl/rat for three weeks, i.p.)] and not treated (DM). At the 11th week, three groups (control, DM, and DM + hWJ-MSCs-CM) were kept in metabolic cages, and urine was collected for 24 h. The serum samples were maintained for measuring fasting blood glucose (FBG) and kidney and liver functional analysis. The left kidney and liver parts were kept at -80 °C to assess apelin and transforming growth factor-beta (TGF-β) expression. The right kidney, pancreas, and liver parts were used for histopathologic evaluation.

RESULTS

DM was detected by higher FBG, microalbuminuria, increased albumin/creatinine ratio, and pancreas, renal, and hepatic structural disturbances. Diabetic hepatopathy was determined by increasing liver enzymes and decreasing total bilirubin. The TGF-β gene expression was significantly upregulated in the diabetic kidney and liver tissues. Apelin gene expression was significantly downregulated in the diabetic liver tissue but did not change in kidney tissue. Administration of hWJ-MSCs-CM improved renal and hepatic functional and structural disturbances. Moreover, CM therapy significantly decreased TGF-β expression and enhanced apelin expression in the kidney and liver tissues.

CONCLUSION

Human WJ-MSCs-CM may have protective effects on diabetic renal and hepatic complications. These effects may happen through the regulation of TGF-β and apelin signaling pathways.

Investigation of conditioned medium properties obtained from human umbilical cord mesenchymal stem/stromal cells preconditioned with dimethyloxalylglycine in a correlation with ultrastructural changes

Mesenchymal stem/stromal cells (MSCs) hold significant therapeutic value due to their regeneration abilities, migration capacity, and immunosuppressive and immunomodulatory properties. These cells secrete soluble and insoluble factors, and this complex secretome contributes to their therapeutic effect. Furthermore, stimulation of cells by various external stimuli lead to secretome modifications that can increase the therapeutic efficacy. So, this study examined the effect of dimethyloxalylglycine (DMOG), a hypoxia-mimetic agent, on secretome profiles and exosome secretions of MSCs by evaluating conditioned medium (CM) and ultrastructural morphologies of the cells in comparison with unpreconditioned MSCs. The appropriate dose and duration of the use of DMOG were determined as 1000 μM and 24 h by evaluating the HIF-1α expression. DMOG-CM and N-CM were collected from MSCs incubated in serum-free medium with/without DMOG for 24 h, respectively. The content analysis of conditioned mediums (CMs) revealed that VEGF, NGF, and IL-4 levels were increased in DMOG-CM. Subsequently, exosomes were isolated from the CMs and were shown by transmission electron microscopy and Western blot analysis in both groups. The effects of CMs on proliferation and migration were determined by in vitro wound healing tests; both CMs increased the fibroblast's migratory and proliferative capacities. According to the ultrastructural evaluation, autophagosome, autolysosome, myelin figure, and microvesicular body structures were abundant in DMOG-preconditioned MSCs. Consistent with the high number of autophagic vacuoles, Beclin-1 expression was increased in those cells. These findings suggested that DMOG could alter MSCs' secretion profile, modify their ultrastructural morphology accordingly, and make the CM a more potent therapeutic tool. RESEARCH HIGHLIGHTS: Preconditioning mesenchymal stem/stromal cells with dimethyloxalylglycine, a hypoxia-mimetic agent, could modify cellular metabolism. Hypoxic mechanisms lead to alterations in the ultrastructural characteristics of mesenchymal stromal/stem cells. Preconditioning with dimethyloxalylglycine leads to ultrastructural and metabolic changes of mesenchymal stromal/stem cells along with modifications in their secretome profiles. Preconditioning of mesenchymal stromal/stem cells could render them a more potent therapeutic tool.

Iron Chelator Deferoxamine Alleviates Progression of Diabetic Nephropathy by Relieving Inflammation and Fibrosis in Rats

Diabetic nephropathy (DN) is one of the most devastating diabetic microvascular complications. It has previously been observed that iron metabolism levels are abnormal in diabetic patients. However, the mechanism by which iron metabolism levels affect DN is poorly understood. This study was designed to evaluate the role of iron-chelator deferoxamine (DFO) in the improvement of DN. Here, we established a DN rat model induced by diets high in carbohydrates and fat and streptozotocin (STZ) injection. Our data demonstrated that DFO treatment for three weeks greatly attenuated renal dysfunction as evidenced by decreased levels of urinary albumin, blood urea nitrogen, and serum creatinine, which were elevated in DN rats. Histopathological observations showed that DFO treatment improved the renal structures of DN rats and preserved podocyte integrity by preventing the decrease of transcripts of nephrin and podocin. In addition, DFO treatment reduced the overexpression of fibronectin 1, collagen I, IL-1β, NF-κB, and MCP-1 in DN rats, as well as inflammatory cell infiltrates and collagenous fibrosis. Taken together, our findings unveiled that iron chelation via DFO injection had a protective impact on DN by alleviating inflammation and fibrosis, and that it could be a potential therapeutic strategy for DN.

Advances in the applications of mesenchymal stem cell-conditioned medium in ocular diseases

Mesenchymal stem cell-conditioned medium (MSC-CM), also known as secretome, is secreted by MSC and contains a variety of bioactive factors with anti-inflammatory, anti-apoptotic, neuroprotection, and proliferation effects. Increasing evidence proved that MSC-CM plays an important role in various diseases, including skin, bone, muscle, and dental diseases. However, the role of MSC-CM in ocular diseases is not quite clear, Therefore, this article reviewed the composition, biological functions, preparation, and characterization of MSC-CM and summarized current research advances in different sources of MSC-CM in corneal and retinal diseases, including dry eye, corneal epithelial damage, chemical corneal injury, retinitis pigmentosa (RP), anterior ischemic optic neuropathy (AION), diabetic retinopathy (DR), and other retinal degenerative changes. For these diseases, MSC-CM can promote cell proliferation, reduce inflammation and vascular leakage, inhibit retinal cell degeneration and apoptosis, protect corneal and retinal structures, and further improves visual function. Hence, we summarize the production, composition and biological functions of MSC-CM and focus on describing its mechanisms in the treatment of ocular diseases. Furthermore, we look at the unexplored mechanisms and further research directions for MSC-CM based therapy in ocular diseases.

2D and 3D cultured human umbilical cord-derived mesenchymal stem cell-conditioned medium has a dual effect in type 1 diabetes model in rats: immunomodulation and beta-cell regeneration

BACKGROUND

Type 1 diabetes (T1D) is a T-cell-mediated autoimmune disease characterized by the irreversible destruction of insulin-producing β-cells in pancreatic islets. Helper and cytotoxic T-cells and cytokine production, which is impaired by this process, take a synergetic role in β-cell destruction, and hyperglycemia develops due to insulin deficiency in the body. Mesenchymal stem cells (MSCs) appear like an excellent therapeutic tool for autoimmune diseases with pluripotent, regenerative, and immunosuppressive properties. Paracrine factors released from MSCs play a role in immunomodulation by increasing angiogenesis and proliferation and suppressing apoptosis. In this context, the study aims to investigate the therapeutic effects of MSC's secretomes by conditioned medium (CM) obtained from human umbilical cord-derived MSCs cultured in 2-dimensional (2D) and 3-dimensional (3D) environments in the T1D model.

METHODS

First, MSCs were isolated from the human umbilical cord, and the cells were characterized. Then, two different CMs were prepared by culturing MSCs in 2D and 3D environments. The CM contents were analyzed in terms of total protein, IL-4, IL-10, IL-17, and IFN-λ. In vivo studies were performed in Sprague-Dawley-type rats with an autoimmune T1D model, and twelve doses of CM were administered intraperitoneally for 4 weeks within the framework of a particular treatment model. In order to evaluate immunomodulation, the Treg population was determined in lymphocytes isolated from the spleen after sacrification, and IL-4, IL-10, IL-17, and IFN-λ cytokines were analyzed in serum. Finally, β-cell regeneration was evaluated immunohistochemically by labeling Pdx1, Nkx6.1, and insulin markers, which are critical for the formation of β-cells.

RESULTS

Total protein and IL-4 levels were higher in 3D-CM compared to 2D-CM. In vivo results showed that CMs induce the Treg population and regulate cytokine release. When the immunohistochemical results were evaluated together, it was determined that CM application significantly increased the rate of β-cells in the islets. This increase was at the highest level in the 3D-CM applied group.

CONCLUSION

The dual therapeutic effect of MSC-CM on immunomodulation and homeostasis/regeneration of β-cells in the T1D model has been demonstrated. Furthermore, this effect could be improved by using 3D scaffolds for culturing MSCs while preparing CM.