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Adipose tissue-derived mesenchymal stromal cells efficiently differentiate into insulin-producing cells in pancreatic islet microenvironment both in vitro and in vivo

BACKGROUND AIMS Differentiation or reprogramming of stem cells could be achieved by remodulating the microenvironment, which regulates the fate of cells by soluble factors and contacts. By providing an in vivo-like microenvironment, directional and functional differentiation of stem cells could be achieved in vitro. In this study, the differentiation of mesenchymal stromal cells (MSCs) derived from rat tissues (adipose, rAT; bone marrow, rBM) were analyzed by in vitro and in vivo co-culture experiments. The insulin-producing capacities of islets transplanted under the renal kidney capsule with rAT- and rBM-MSCs were compared and the reduction of hyperglycemia symptoms in rat models was examined. METHODS MSCs prelabeled with green fluorescence protein were co-cultured with islets directly. The insulin production of cells was determined by immunostaining and ELISA. Streptozotocin-induced diabetic rat models were created and MSCs were co-transplanted with the islets under the kidney capsule to confirm the in vitro results. RESULTS MSCs were differentiated into insulin-producing cells after 38 days of co-culture, confirmed by insulin and C-peptide stainings. In vivo functional studies revealed that the co-culture of islets with MSCs provided higher differentiation efficiency. The weight gain measurement and glucose tolerance test in the rat group co-transplanted of rAT-MSCs and islets indicate a better recovery than islet-alone transplants and co-transplants of islets and rBM-MSCs. CONCLUSIONS rAT-MSCs could be considered as the cell of choice for cell-based treatment of type 1 diabetes. Because the co-transplantation of islets with MSCs increases the number of insulin-producing cells, this method was suggested for clinical applications.

Immunoregulatory effects of human dental pulp-derived stem cells on T cells: comparison of transwell co-culture and mixed lymphocyte reaction systems

BACKGROUND AIMS. Studies performed using human and animal models have indicated the immunoregulatory capability of mesenchymal stromal cells in several lineages. We investigated whether human dental pulp-derived stem cells (hDP-SC) have regulatory effects on phytohemagglutinin (PHA)-activated CD3(+) T cells. We aimed to define the regulatory mechanisms associated with hDP-SC that occur in mixed lymphocyte reaction (MLR) and transwell systems with PHA-CD3(+) T cells and hDP-SC at a ratio of 1:1. METHODS. Proliferation, apoptosis and pro- and anti-inflammatory cytokines of PHA-CD3(+)T cells, the expression of Regulatory T cells (Treg) markers and some regulatory factors related to hDP-SC, were studied in Both transwell and MLR are co-cultures systems. RESULTS. Anti-proliferative and apoptotic effects of hDP-SC were determined in co-culture systems. Elevated expression levels of human leukocyte antigen (HLA)-G, hepatocyte growth factor (HGF)-β1, intracellular adhesion molecule (ICAM-1)-1, interleukin (IL)-6, IL-10, transforming growth factor (TGF)-β1, vascular adhesion molecule (VCAM)-1 and vascular endothelial growth factor (VEGF) by hDP-SC were detected in the co-culture systems. We observed decreased expression levels of pro-inflammatory cytokines [interferon (IFN)-γ, IL-2, IL-6 receptor (R), IL-12, Interleukin-17A (IL-17A), tumor necrosis factor (TNF)-α] and increased expression levels of anti-inflammatory cytokine [inducible protein (IP)-10] from PHA-CD3(+) T cells in the transwell system. Expression of Treg (CD4(+) CD25(+) Foxp3(+)) markers was significantly induced by hDP-SC in both co-culture systems. We observed apoptosis of PHA-CD3(+) T cells with 24 h using time-lapse camera photographs and active caspase labeling; it is likely that paracrine soluble factors and molecular signals secreted by hDP-SC led this apoptosis. CONCLUSIONS. We suggest that hDP-SC have potent immunoregulatory functions because of their soluble factors and cytokines via paracrine mechanisms associated with PHA-CD3(+) T cells, which could contribute to clinical therapies.

Reduction of lesion in injured rat spinal cord and partial functional recovery of motility after bone marrow derived mesenchymal stem cell transplantation.

AIM This study aimed to analyze the effect of rat bone marrow-mesenchymal stem cells (rBM-MSCs) delivery on lesion site after spinal cord injury, and to observe the functional recovery after transplantation. MATERIAL AND METHODS MSCs were isolated from rat femurs and tibias. The experimental rat population was divided into four groups: only laminectomy (1); laminectomy+trauma (2); laminectomy+trauma+PBS (3); laminectomy+trauma+MSCs (4). Their motility were scored regularly. After 4-weeks, rats were sacrificed, and their spinal cords were examined for GFP labeled rBM-MSCs by immunostainings. RESULTS In the early posttraumatic period, the ultrastructures of spinal cord tissue were preserved in Group 4. The majority of cells forming the ependymal region around the central canal were found to be MSCs. The gray-and-white-matter around the ependymal region were composed of Nestin+/GFAP+ cells, with astrocytic-like appearance. The scores showed significant motor recovery in Group 4, especially in hind limb functions. However, no obvious change was observed in other groups. CONCLUSION The increase Nestin+/GFAP+ cells in the gray-and-white-matter around the ependymal region could indicate the potential to self-renew and plasticity. Thus, transplantation of rBM-MSCs might be an effective strategy to improve functional recovery following spinal cord trauma. In conclusion, molecular factors in cell fate decisions could be manipulated to enhance reparative potential of cell-based therapy.

Recovery of Fertility in Azoospermia Rats after Injection of Adipose-Tissue-Derived Mesenchymal Stem Cells: The Sperm Generation

The recent reports on the treatment of azoospermia patients, in which spermatozoa could not be traced in their testes, are focused more on the potential use of adult stem cells, like mesenchymal stem cells (MSCs). The aim of this study was to demonstrate the potential use of MSCs derived from adipose tissue in the treatment of azoospermia using rat disease models. After busulfan application, the rats (n = 20) were injected with the GFP+ MSCs into left rete testes. After 12 weeks, the testes with cell injection (right testes) were compared to control (left testes) after dimensional and immunohistochemical analyses. Testes treated with MSCs appeared morphologically normal, but they were atrophic in rats without stem cell treatment, in which the seminiferous tubules were empty. Spermatogenesis was detected, not in every but in some tubules of cell-treated testes. GFP+/VASA+ and GFP+/SCP1+ cells in testes indicated the transdifferentiation of MSCs into spermatogenetic cells in the appropriate microenvironment. Rats with cell treatment were mated to show the full recovery of spermatogenesis, and continuous generations were obtained. The expression of GFP was detected in the mesenchymal stem cells derived from adipose tissue and bone marrow and also in the sperms of offspring. In conclusion, MSCs might be studied for the same purpose in humans in future.

Neuroprotective effects of intravitreally transplanted adipose tissue and bone marrow–derived mesenchymal stem cells in an experimental ocular hypertension model

BACKGROUND AIMS The purpose of this study was to investigate the neuroprotective effects of bone marrow bone marrow-derived and adipose tissue-derived mesenchymal stromal cells (MSCs) that were intravitreally transplanted in an experimental ocular hypertension (OHT) model. METHODS An OHT rat model was generated by means of intracameral injection of hyaluronic acid into the anterior chamber. MSCs labeled with green fluorescence protein were transplanted intravitreally 1 week after OHT induction. At the end of the second and fourth weeks, retinal ganglion cells were visualized with the use of a flat-mount retina method and were evaluated by means of immunofluorescence staining against green fluorescence protein, vimentin, CD105, and cytokines (interleukin [IL]-1Ra, prostaglandin E2 receptor, IL-6, transforming growth factor-β1, interferon-γ and tumor necrosis factor-α). RESULTS The retinal ganglion cell numbers per area were significantly improved in stem cell-treated OHT groups compared with that in the non-treated OHT group (P < 0.05). The results of immunohistochemical analyses indicated that a limited number of stem cells had integrated into the ganglion cell layer and the inner nuclear layer. The number of cells expressing proinflammatory cytokines (interferon-γ and tumor necrosis factor-α) decreased in the MSC-transferred group compared with that in the OHT group after 4 weeks (P < 0.01). On the other hand, IL-1Ra and prostaglandin E2 receptor expressions were increased in the rat bone marrow-derived MSC group but were more significant in the rat adipose tissue-derived MSC group (P < 0.01). CONCLUSIONS After intravitreal transplantation, MSCs showed a neuroprotective effect in the rat OHT model. Therefore, MSCs promise an alternative therapy approach for functional recovery in the treatment of glaucoma.

IL-6 originated from breast cancer tissue-derived mesenchymal stromal cells may contribute to carcinogenesis

Tumor microenvironment is an important factor, which sustains and promotes the tumors by inflammatory signals. Interleukin-6 (IL-6) is known as a multifunctional cytokine, which is a major activator of the signaling pathway of Janus kinases (JAKs)/signal transducer and activator of transcription 3 (STAT3). In this study, we aimed to investigate the effect of IL-6 in the tumor microenvironment on carcinogenesis. For this purpose, healthy breast tissue-derived stromal cells (HBT-SCs) and malign breast tissue-derived stromal cells (MBT-SCs) were co-cultured with MCF-7 (human breast adenocarcinoma cell line) cells using semipermeable membranes. The cell proliferation was monitored with water-soluble tetrazolium (WST) and carboxyfluorescein succinimidyl ester (CFSE) assays. Protein levels were measured by enzyme-linked immunosorbent assay (ELISA) and Western blot hybridization, while gene expressions were measured by real-time PCR. The results demonstrated that IL-6 protein levels increased significantly in the supernatants of MBT-SCs when they were co-cultured with MCF-7 cells. In accordance with this, the expression of IL-6 was significantly higher in MBT-SCs. Additionally, the expression of STAT3 in MCF-7 cells increased slightly when they were co-cultured with MBT-SCs. Considering together, there is an important interaction between tumor microenvironment and tumor cells mediated by IL-6 signaling. Thereby, the targeting on IL-6 signaling in the treatment of cancer might effectively prevent the tumor progression.

Cross Effects of Resveratrol and Mesenchymal Stem Cells on Liver Regeneration and Homing in Partially Hepatectomized Rats

In this study, we examined the effect of preoperatively administered resveratrol (RV) and mesenchymal stem cells (MSCs) on regeneration of partially hepatectomized rat liver. We also evaluated the effect of RV on homing of MSCs. MSCs were isolated from bone marrow and cultured in vitro. Wistar albino rats were randomly divided into four groups. In groups, rats received (1) no treatment, (2) single dose RV, (3) MSCs and (4) RV plus MSCs before partial hepatectomy (PH). Injected MSCs were traced by labeling them with green fluorescent protein, and liver regeneration was determined by comparison of liver weight gain, histological examination and immunohistochemical staining with proliferating cell nuclear antigen (PCNA) for mitotic cells. The expression levels of tumor necrosis factor –alpha (TNF-α), interleukin-6 (IL-6) and hepatocyte growth factor (HGF) were also determined in the parafin sections of liver specimens with immunohistochemical staining. Administration of RV and MSCs separately or together enhanced liver regeneration despite decreasing the TNF-α and IL-6 expression. This positive contribution was probably due to direct raising effect on HGF for RV and HGF expression for MSCs that we demonstrated with immunohistochemical staining. Additionally, RV increased the homing of MSCs in liver probably related to life prolonging effect on MSCs. These results indicate that preoperative RV as well as MSCs application enhances liver regeneration after partial hepatectomy in rats. Paying attention to RV about the effect on liver regeneration and homing of MSCs might be the goal of further investigations.

The effects of dental pulp stem cells on bone regeneration in rat calvarial defect model: micro-computed tomography and histomorphometric analysis.

OBJECTIVE Stem cell therapies may be applicable to all fields of medicine, including craniomaxillofacial surgery. Dental pulp stem cells also have significant osteogenic properties. This study aimed to evaluate the influence of dental pulp stem cells on bone regeneration and to ascertain whether or not there was any superiority over traditional methods. DESIGN In this study, 15 non-immunodeficient Wistar albino rats were used. The rats were divided into three groups: (1) untreated control group; (2) hydroxyapatite tri-calcium-phosphate (HA/TCP) paste; (3) human dental pulp derived stem cells (DPSC) mixed with HA/TCP paste (HA/TCP+DSPC group, n=10). Two symmetrical full-thickness cranial defects were created on each parietal region (10 defects for each group). The animals were sacrificed 8 weeks post-surgery and samples were analyzed by microcomputer tomography (μ-CT) and histomorphometry. RESULTS The calcification rate and bone mineral density (BMD) values in Group 3 were found to be significantly higher than in the other two groups. Radiographically, bone regeneration was greater in Group 2 compared with the control group. However, there was no significant difference between Groups 2 and 1 in respect of histological analysis. CONCLUSIONS According to the results of the present study, DPSCs may be a suitable factor for bone tissue engineering because they can be easily obtained and differentiate into bone cells.

Mesenchymal Stem Cell: Does it Work in an Experimental Model with Acute Respiratory Distress Syndrome?

We hypothesized that bone marrow-derived mesenchymal stem cells (BM-MSCs) would have a possible role in the treatment of acute respiratory distress syndrome (ARDS). ARDS disease model was developed in Wistar albino male rats by intratracheal instillation of physiological saline solution. Anesthezied and tracheotomized rats (n = 8) with ARDS were pressure-controlled ventilated. Isolated and characterized rat (r-) BM-MSCs were labeled with GFP gene, and introduced in the lungs of the ARDS rat-model. After applying of MSCs, the life span of each rat was recorded. When rats died, their lung tissues were removed for histopathological examination. Also the tissue sections were analyzed for GFP labeled rBM-MSCs and stained for vimentin, CK19, proinflammatory (MPO, IL-1β, IL-6 and MIP-2) and anti-inflammatory [IL-1ra and prostaglandin E2 receptor (EP3)] cytokines. The histopathological signs of rat-model ARDS were similar to the acute phase of ARDS in humans. rBM-MSCs were observed to home in lung paranchyma. Although the infiltration of neutrophils slightly decreased in the interalveolar, peribronchial and perivascular area, a notable improvement was determined in the degree of hemorrhage, edema and hyaline membrane formation in rats treated with rBM-MSCs. Also decreased proinflammatory cytokines levels and increased the intensity of anti-inflammatory cytokines were established. Therefore MSCs could promote alveoar epithelial repair by mediating of cytokines from a proinflammatory to an anti-inflammatory response. As a novel therapeutic approach, mesenchymal stem cell treatment with intratracheal injection could be helpful in the management of critically ill patients with ARDS.

Comparison of the early period effects of bone marrow-derived mesenchymal stem cells and platelet-rich plasma on the Achilles tendon ruptures in rats

ABSTRACT Introduction: This study aims to histopathologically, biomechanically, and immunohistochemically compare the fourth-week efficiencies of local platelet-rich plasma (PRP) and bone marrow-derived mesenchymal stem cell (rBM-MSC) treatments of the Achilles tendon ruptures created surgically in rats. Materials and Methods: The study included 35 12-month-old male Sprague Dawley rats, with an average weight of 400–500 g. Five rats were used as donors for MSC and PRP, and 30 rats were separated into MSC, PRP, and control groups (n = 10). The Achilles tendons of the rats were cut transversely, the MSC from bone marrow was administered to the MSC group, the PRP group received PRP, and the control group received physiological saline to create the same surgical effect. In previous studies, it was shown that this physiological saline does not have any effect on tendon recovery. Thirty days after the treatment, the rats were sacrificed and their Achilles tendons were examined histopathologically, immunohistochemically, and biomechanically. Results: The use of rBM-MSC and PRP in the Achilles tendon ruptures when the tendon is in its weakest phase positively affected the recovery of the tendon in histopathologic, immunohistochemical, and biomechanical manners compared to the control group (p < 0.05). While the levels of pro-inflammatory cytokines TNF-α, IFNγ, and IL 1β were significantly low, the levels of anti-inflammatory cytokines and growth factors playing key roles in tendon recovery, such as IL2, VEGF, transforming growth factor-beta, and HGF, were significantly higher in the MSC group than those of the PRP and control groups (p < 0.05). In the MSC group, the (mm) value was significantly higher (p ˂ 0.05) than that in the PRP and control groups. Conclusion: rBM-MSC and PRP promote the recovery of the tendon and increase its structural strength. The use of PRP and MSC provides hope for the treatment of the Achilles tendon ruptures that limit human beings’ functionalities and quality of life, particularly for athletes. It is thought that the use of MSC can be more effective for tendon healing; hence, more extensive and advanced studies are needed on this topic.