Investigation of the differentiation potential of pericyte cells as an alternative source of mesenchymal stem cells.

BACKGROUND: The mesenchymal stem cells (MSCs) with characterized by their multipotency and capacity to differentiate into various tissue cell types, have led to their incorporation in regenerative medicine research. However, the limited numbers of MSCs in the human body and their diverse differentiation capabilities in tissues highlight the need for exploring alternative regenerative cell sources. In this study, therefore, we conducted molecular level examinations to determine whether pericytes, specialized cell communities situated near blood vessels, could serve as a substitute for human bone marrow-derived mesenchymal stem cells (hBM-MSCs). In this context, the potential application of pericytes surrounds the vessels when MSCs are insufficient for functional purposes. METHODS: The pericytes utilized in this investigation were derived from the placenta and characterized at the third passage. Similarly, the hBM-MSCs were also characterized at the third passage. The pluripotent properties of the two cell types were assessed at the gene expression level. Thereafter, both pericytes and hBM-MSCs were directed towards adipogenic, osteogenic and chondrogenic differentiation. The cells in both groups were examined on days 7, 14, and, 21 and their differentiation status was compared both immunohistochemically and through gene expression analysis. RESULTS: Upon comparing the pluripotency characteristics of placental pericytes and hBM-MSCs, it was discovered that there was a substantial upregulation of the pluripotency genes FoxD3, Sox2, ZPF42, UTF1, and, Lin28 in both cell types. However, no significant expression of the genes Msx1, Nr6a1, Pdx1, and, GATA6 was observed in either cell type. It was also noted that pericytes differentiate into adipogenic, osteogenic and, chondrogenic lineages similar to hBM-MSCs. DISCUSSION: As a result, it has been determined that pericytes exhibit high differentiation and proliferation properties similar to those of MSCs, and therefore can be considered a suitable alternative cell source for regenerative medicine and tissue engineering research, in cases where MSCs are not available or insufficient. It is notable that pericytes have been suggested as a potential substitute in studies where MSCs are lacking.

Production of alginate macrocapsule device for long-term normoglycaemia in the treatment of type 1 diabetes mellitus with pancreatic cell sheet engineering.

Type 1 diabetes-mellitus (T1DM) is characterized by damage of beta cells in pancreatic islets. Cell-sheet engineering, one of the newest therapeutic approaches, has also been used to create functional islet systems by creating islet/beta cell-sheets and transferring these systems to areas that require minimally invasive intervention, such as extrahepatic areas. Since islets, beta cells, and pancreas transplants are allogeneic, immune problems such as tissue rejection occur after treatment, and patients become insulin dependent again. In this study, we aimed to design the most suitable cell-sheet treatment method and macrocapsule-device that could provide long-term normoglycemia in rats. Firstly, mesenchymal stem cells (MSCs) and beta cells were co-cultured in a temperature-responsive culture dish to obtain a cell-sheet and then the cell-sheets macroencapsulated using different concentrations of alginate. The mechanical properties and pore sizes of the macrocapsule-device were characterized. The viability and activity of cell-sheets in the macrocapsule were evaluatedin vitroandin vivo. Fasting blood glucose levels, body weight, and serum insulin & C-peptide levels were evaluated after transplantation in diabetic-rats. After the transplantation, the blood glucose level at 225 mg dl-1on the 10th day dropped to 168 mg dl-1on the 15th day, and remained at the normoglycemic level for 210 days. In this study, an alginate macrocapsule-device was successfully developed to protect cell-sheets from immune attacks after transplantation. The results of our study provide the basis for future animal and human studies in which this method can be used to provide long-term cellular therapy in T1DM patients.

Examining the effect of activated cytotoxic (CD8+) T-cell exosomes to the lung cancer.

Lung cancer continues to be a major health problem worldwide owing to its incidence, and causes physical, psychological, social, and economic problems. Activated cytotoxic T cells (ACTC) are positively correlated with the tumor microenvironment (TME), improving the prognosis of cancer patients. Recently, ACTC-derived exosomes (ACTC-dExo) were implicated in this effect by inhibiting mesenchymal stem cells, which may promote metastasis in the TME. Exosomes are thought to be advantageous for the specific delivery of drugs to cancer cells because they have the characteristics of natural liposomes, are nanosized, and remain largely stable in the blood due to the protein and lipid content they carry on their membranes. In this study, we aimed to determine the cytotoxic and metastatic inhibitory effects of ACTC-dExo in A549 cells in vitro. Cytotoxic CD8+ T cells were isolated from whole blood obtained from healthy individuals and cultured for 5-7 days after stimulation. The ACTC-dExo serum-free culture medium was collected by ultracentrifugation. Characterization and quantification of the isolated exosomes were performed using flow cytometry, electron microscopy, zeta-sizer measurements, and bicinchoninic acid (BCA) assays. We co-cultured ACTC and ACTC-dExo with A549 cells for 48 h. The viability of A549 cells was evaluated using a WST-1 assay. The metastasis-related genes MMP2, MMP9, TWIST, SNAI1, and CDH1 were detected by qRT-PCR, and MMP2 and MMP9 proteins were evaluated by confocal microscopy. In addition, changes in cell migration were investigated using a scratch assay. ACTC-dExo were found to have anti-proliferative and anti-metastatic effects and reduced cancer cell proliferation and metastatic properties.

Investigation of impacts of decellularized heart extracellular matrix and VEGF on cardiomyogenic differentiation of mesenchymal stem cell through Notch/Hedgehog signaling pathways.

OBJECTIVE: Decellularization is the process to obtain natural scaffolds with tissue integrity and extracellular matrix components, and recellularization is used to produce tissue-like constructs with specific cell types. In this study, rat bone marrow-derived mesenchymal stem cells (rBM-MSCs) were cultured on decellularized heart extracellular matrix. These cells were then induced to differentiate into cardiomyogenic cells under the stimulatory effect of vascular endothelial growth factor (VEGF) and other chemicals. This study aimed to investigate the effect of the cardiac extracellular matrix and VEGF on cardiomyogenic differentiation in the context of the Notch and Hedgehog signaling pathways. METHODS: Heart samples extracted from rats were decellularized by serial application of detergent to remove cells from the tissue, and then recellularized with rBM-MSCs. The recellularized tissue matrices were then analyzed for cardiomyogenesis. Cardiomyogenic differentiation was performed on decellularized heart extracellular matrix (ECM; three-dimensional scaffolds) and culture plates (two-dimensional cell culture system) for 28 days to understand the effects of the heart extracellular matrix. In addition, differentiation was induced with and without the stimulatory effect of VEGF to understand the effect of VEGF on cardiomyogenic differentiation of rBM-MSCs. RESULTS: Immunofluorescence staining showed that decellularization of the heart was performed effectively and successfully. After decellularization process, the heart extracellular matrix was completely free of cells. It was observed that rBM-MSCs transplanted onto the heart extracellular matrix remained viable and proliferated for 21 days after recellularization. The rBM-MSCs promoted cardiomyogenic differentiation in the conventional differentiation medium but were inversely affected by both VEGF and heart extracellular matrix proteins. Lower expression of connexin43 and cardiac troponin I genes was observed in cells induced by either matrix proteins or VEGF, compared to cells differentiated by chemical agents alone. CONCLUSION: In this study, we investigated the effect of decellularized heart extracellular matrix and VEGF on cardiomyogenic differentiation of rBM-MSCs. On the decellularized cardiac extracellular matrix, rBM-MSCs maintained their viability by adhering to the matrix and proliferating further. The adhesion of the cells to the matrix also produced a physical stimulus that led to the formation of histological structures resembling myocardial layers. Chemical stimulation of the decellularized heart extracellular matrix and cardiomyogenic differentiation supplements resulted in increased expression of cardiomyogenic biomarkers through modulation of the Notch and Hedgehog signaling pathways.

Resveratrol improves vascular endothelial dysfunction in the unpredictable chronic mild stress model of depression in rats by reducing inflammation.

Chronic psychological stress may cause depression and it is a risk factor for vascular endothelial dysfunction. Inflammation may contribute to endothelial dysfunction. Resveratrol, which has antiinflammatory and vasculoprotective properties, has been reported its beneficial effects on endothelial dysfunction induced by hypertension, diabetes and, aging. The effects of resveratrol on stress-induced endothelial dysfunction is not investigated yet. This study aimed to investigate the efficacy of resveratrol on vascular function in the unpredictable chronic moderate stress (UCMS) model of rats and to examine the possible mechanisms of resveratrol by assessment of proinflammatory markers. Male rats were assigned to 4 groups (n = 8 for each group): Control, Control+Resveratrol, UCMS, UCMS+Resveratrol. UCMS and UCMS+Resveratrol groups were exposed to the UCMS procedure for 12 weeks. Resveratrol (20 mg/kg/day, i.p., during 12 weeks) was given to the Control+Resveratrol and UCMS+Resveratrol groups.Then depressive-like behaviors were evaluated by forced swimming test. After behavioral tests, systolic blood pressure was recorded. Endothelial function of the thoracic aorta was evaluated by isolated organ bath system. Vascular eNOS expression and inflammatory markers such as TNF-α, IL-1ß, IL-6, CRP, ICAM1, MCP in serum and vascular tissue were analyzed to explore the mechanisms of resveratrol. UCMS resulted in depressive-like behavior, endothelial dysfunction and increased inflammatory cytokines in both serum and tissue samples. Resveratrol treatment improved depressive-like behavior, ameliorated vascular dysfunction, and reversed stress-induced inflammation. Our findings suggest that resveratrol exerted antidepressant-like effect and prevented vascular endothelial dysfunction by reducing systemic and peripheral inflammation in UCMS-induced depression in rats. Therefore, resveratrol may be a therapeutic option with a vasculoprotective effect in depression.

Etanercept Prevents Endothelial Dysfunction in Cafeteria Diet-Fed Rats.

Obesity is associated with endothelial dysfunction and this relationship is probably mediated in part by inflammation. Objective: The current study evaluated the effects of etanercept, a tumor necrosis factor-alpha (TNF-α) inhibitor, on endothelial and vascular reactivity, endothelial nitric oxide synthase (eNOS) immunoreactivity, and serum and aortic concentrations of TNF-α in a diet-induced rat model. Design and results: Male weanling Wistar rats were exposed to a standard diet and cafeteria diet (CD) for 12 weeks and etanercept was administered during CD treatment. Isolated aortas of the rats were used for isometric tension recording. Carbachol-induced relaxant responses were impaired in CD-fed rats, while etanercept treatment improved these endothelium-dependent relaxations. No significant change was observed in papaverine- and sodium nitroprusside (SNP)-induced relaxant responses. eNOS expression decreased in CD-fed rats, but no change was observed between etanercept-treated CD-fed rats and control rats. CD significantly increased both the serum and the aortic levels of TNF-α, while etanercept treatment suppressed these elevated levels. CD resulted in a significant increase in the body weight of the rats. Etanercept-treated (ETA) CD-fed rats gained less weight than both CD-fed and control rats.

THE EFFECTS OF ETANERCEPT AND CABERGOLINE ON ENDOMETRIOTIC IMPLANTS, UTERUS AND OVARIES IN RAT ENDOMETRIOSIS MODEL.

The pathophysiology of endometriosis is still unknown and treatment options remain controversial. Searches focus on angiogenesis, stem cells, immunologic and inflammatory factors. This study investigated the effects of etanercept and cabergoline on ovaries, ectopic, and eutopic endometrium in an endometriosis rat model. This randomized, placebo-controlled, blinded study included 50 rats, Co(control), Sh(Sham), Cb(cabergoline), E(etanercept), and E + Cb(etanercept + cabergoline) groups. After surgical induction of endometriosis, 2nd operation was performed for endometriotic volume and AMH level. After 15 days of treatment: AMH level, flow cytometry, implant volume, histologic scores, immunohistochemical staining of ectopic, eutopic endometrium, and ovary were evaluated at 3rd operation. All groups had significantly reduced volume, TNF-α, VEGF, and CD 146/PDGF-Rß staining of endometriotic implants comparing to the Sh group (p < 0.05).TNF-α staining of eutopic endometrium in all treatment groups was similar to Sh and Co groups (p > 0.05). E and E + Cb groups significantly decreased TNF-α staining in the ovary comparing to Sh, Co, and Cb groups (p < 0.05). All treatment groups had significantly higher AFC compared to the Sh group. CD25+ Cells' median percentage was significantly increased in the E + Cb group compared to Co, Sh, Cb, and E group. E + Cb group had a significantly higher CD5+ Cells' level than the Co group (p = 0.035). In conclusion; Etanercept and/or Cabergoline decreased volume, TNF-α, VEGF, and CD 146/PDGF-Rß staining of the ectopic endometrial implant. E and E + Cb treatment decreased TNF-α levels in the ovary. E + Cb also increased peripheral blood CD25+ & CD5+ Cell's.

Etanercept improves aging-induced cognitive deficits by reducing inflammation and vascular dysfunction in rats.

Normal aging may lead to cognitive deficits, which is associated with endothelial dysfunction and neuroinflammation. Dysregulation of TNFα expression contributes to vascular aging and dementia. In this study, we investigated the effects of etanercept, which is a TNFα inhibitor, on cognitive and endothelial function in aged rats. Male Wistar albino rats were divided into 3 groups: Young (4 month), aged (24 month) aged+ETA (24 month+etanercept). Etanercept (0.8 mg/kg/weekly) was given to the aged+ETA group subcutaneously for 8 weeks. Then passive avoidance test (PAT) and the Morris water maze test (MWMT) were used to evaluate cognitive functions of rats. After the behavioral tests, the rats were subjected to systolic blood pressure (SBP) measurement, and then endothelial function of thoracic aorta was evaluated by isolated organ bath system. Thoracic eNOS expression, hippocampal BDNF expression and serum and hippocampal TNF levels were also measured. In aged rats, it was shown that cognitive performances in MWMT and PAT were abolished whereas SBP unchanged. Furthermore, aging resulted in endothelial dysfunction, decreased expressions of thoracic eNOS and hippocampal BDNF, and increased level of TNF in serum and hippocampus. In contrast, ETA improved age-related cognitive deficits and endothelial dysfunction. In addition, ETA reversed changes in protein expression in aged rats. The results of this study indicate that ETA prevents cognitive deficits, endothelial dysfunction, peripheral and neuro-inflammation and decreament of neurotrophin expression in aged rats. These findings suggest that ETA may be beneficial with neuroprotective and vasculoprotective effects in elderly patients.

Restorative effect of resveratrol on expression of endothelial and neuronal nitric oxide synthase in cavernous tissues of chronic unpredictable mild stress-exposed rats: an impact of inflammation.

We investigated the effect of resveratrol on endothelial and neuronal nitric oxide synthase (eNOS and nNOS) expression in the corpus cavernosum from chronic unpredictable mild stress (CUMS)-exposed rats in order to examine possible role of proinflammatory cytokines, which might play a role on erectile dysfunction (ED). Rats were randomly and equally divided into four groups such as control, control+resveratrol, CUMS and CUMS + resveratrol (20 mg/kg/day, i.p/8 weeks). Sucrose intake and forced swimming tests were used to evaluate depressive-like behaviors. nNOS, eNOS expressions, inflammatory markers, corticosterone and testosterone levels were analyzed either in blood samples and/or penile tissues. CUMS-exposed rats displayed depressive-like behaviors, reduced penile nNOS and eNOS expressions, and serum testosterone levels and enhanced serum and penile tissue levels of proinflammatory markers compared to controls. Resveratrol reversed depressive-like behaviors and suppressed serum and penile levels of proinflammatory markers, increased nNOS and eNOS expressions and testosterone levels in CUMS-exposed rats. Resveratrol exerted antidepressant-like effects and protected the development of CUMS-induced impairment of cavernosal eNOS and nNOS expressions associated with ED, which might be related to its anti-inflammatory action.

Depression induced by chronic stress leads to penile cavernosal dysfunction: protective effect of anti-TNF-α treatment.

Psychological stress may lead to erectile dysfunction (ED), and inflammation has been evaluated as a major contributing factor. The goal of this study was to investigate the effects of etanercept (ETN), an anti-tumor necrosis factor α (TNF-α) protein, on cavernosal function in the unpredictable chronic mild stress (UCMS) rat model of depression. Animals were divided into 4 groups: animals not exposed to UCMS, animals not exposed to UCMS and treated with ETN, animals exposed to UCMS, and animals treated with ETN while exposed to UCMS. UCMS significantly impaired the neurogenic and endothelium-dependent relaxation responses; reduced cavernosal endothelial nitric oxide (NO) synthase (eNOS) and neuronal NO synthase (nNOS) expressions; decreased testosterone levels; enhanced systemic levels of corticosterone, TNF-α, interleukin 1ß (IL-1ß), interleukin 6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and intercellular adhesion molecule 1 (ICAM-1); and also increased cavernosal levels of TNF-α, IL-1ß, and IL-6 in rats. ETN administration restored NO-mediated neurogenic and endothelium-dependent relaxation responses of the corpus cavernosum, increased cavernosal eNOS and nNOS expressions, enhanced testosterone levels, and decreased corticosterone levels in UCMS-exposed rats. Also, systemic inflammatory markers and cavernosal proinflammatory cytokine levels were reduced by ETN. Our results demonstrate the role of TNF-α-mediated inflammation in the development of depression and ED in rats exposed to chronic stress.

TNF-α antagonism with etanercept enhances penile NOS expression, cavernosal reactivity, and testosterone levels in aged rats.

Erectile dysfunction (ED) has been reported to be associated with inflammation. This study investigated the effects of tumor necrosis factor alpha (TNF-α) inhibitor etanercept on penile neuronal nitric oxide synthase (nNOS) and endothelial nitric oxide synthase (eNOS) expressions, testosterone concentrations, neurogenic and endothelium-dependent relaxations of corpus cavernosum (CC), and circulating and cavernosal levels of inflammatory markers in aged rats. Animals were separated into control, aged, and etanercept-treated aged groups. Aged rats displayed significantly increased serum and cavernosal TNF-α, C-reactive protein (CRP), monocyte chemoattractant protein-1 (MCP-1) and intercellular adhesion molecule (ICAM-1) levels, and decreased penile nNOS and eNOS expressions and serum testosterone levels compared with controls. In etanercept-treated aged group, NOS expressions were similar to that of the control group. The circulating and cavernosal concentrations of TNF-α, CRP, MCP-1, ICAM-1, and testosterone were also normalized by etanercept. Neurogenic and endothelium-dependent relaxant responses significantly decreased in aged rats and etanercept treatment markedly improved these relaxation responses. Our findings indicate that aging decreases penile NOS expression, neurogenic and endothelium-dependent relaxations of CC, and also suppresses serum testosterone levels by inducing inflammatory response that may contribute to the development of ED. TNF-α antagonism may be a novel strategy to treat aging-associated ED.

Improvement of the insulin secretion from beta cells encapsulated in alginate/poly-L- histidine/alginate microbeads by platelet-rich plasma.

Type 1 diabetes is clinically characterized as the loss of control of glucose homeostasis due to the reduced number of insulinproducing cells. Long-term glycemic control after implantation could be maintained by preserving the cell viability and tissue-specific functions during the process of microencapsulation. In this study, alginate solution was supplemented with platelet-rich plasma (PRP) to improve the viability and preserve the cell functions during the encapsulation of a beta cell line (BRIN-BD11). Cell viability was assessed and insulin secretion and insulin stimulation index were evaluated. eTh polymerization of alginate with PRP enhanced the viability up to 61% in the alginate microbeads. PRP supplementation to the alginate composition not only increased the number of viable cells by 1.95-fold, but the insulin secretion also improved by about 66%. eTh stimulation index, however, was not affected by the PRP supplementation.

The distribution of CD44+/CD24- cancer stem cells in breast cancer and its relationship with prognostic factors.

PURPOSE: The purpose of this study was to investigate the correlation between the percentages of CD44+/CD24- cancer stem cells (CSCs) and the clinicopathological and prognostic factors in breast cancer patients. METHODS: Twenty three women who underwent surgery for breast cancer were enrolled in this study. The mean age of the patients was 46.65 years and 52% had early-stage disease. Tumor tissues obtained during surgery were digested enzymatically. CD44+/CD24- cell phenotype was identified by using surface marker antibodies and percentages were determined by surface marker expression of the cells. RESULTS: Sixty five percent of the tumors were positive for estrogen (ER)/ progesterone receptors (PR) and 38% of the tumors were positive for HER-2. All of the patients with hormone receptor positive tumors had ER positive tumors, while only 11 patients had PR positive breast cancer. CD44+/CD24- cells were present in all tumor tissues. The mean proportion of the CD44+/CD24- cells was 1.43±1.6. The mean percentages of CD18+ cells and MUC1+ were 27.9±26.5% and 6.07±11.34%, respectively. The percentage of CD18+ cells was significantly higher in PR positive tumors (p=0.042). There was no significant correlation between the percentage of CD44+/CD24- cells and clinicopathological features. CONCLUSION: This study showed that CD44+/CD24- cells were present in all tumor tissues. The percentage of CD44+/CD24- cells was higher in early-stage disease, yet without statistical significance. No correlation was found between prognostic factors and the percentage of the CD44+/CD24- cells.

Protective effects of resveratrol on aging-induced cognitive impairment in rats.

Resveratrol, a polyphenol phytoalexine, has been shown to play a neuroprotective role in the neurodegenerative process in Alzheimer's disease (AD) and improve memory function in dementia. However, the in vivo effect of resveratrol in normal aging models of learning and memory has not yet been evaluated. Therefore, the present neurobehavioral study was undertaken to evaluate the effect of resveratrol on cognitive impairment induced by aging in passive avoidance and Morris water maze (MWM) tests. Male Wistar albino rats were divided into four groups: young control (4month), young resveratrol (4month+RESV), old control (24month) and old resveratrol (24month+RESV). Resveratrol (50mg/kg/day) was given to the 4month+RESV and 24month+RESV groups orally for 12weeks. There was no significant difference between the groups for the first day of latency, while in aged rats, the second day of latency was significantly shortened compared to the young group in the passive avoidance test (p<0.05). Additionally, in the MWM test, the results showed a decrease in the time spent in the escape platform's quadrant in the probe test in aged rats (p<0.05). The administration of resveratrol at 50mg/kg/day increased the retention scores in the passive avoidance test and the time spent in the escape platform's quadrant in the MWM task (p<0.05). Furthermore resveratrol attenuated the protein levels of TNFα and IL1ß in the 24-month group. These findings indicate that aging impairs emotional and spatial learning-memory and resveratrol reverses the effect of age-related learning and memory impairment. The results of this study suggest that resveratrol is effective in preventing cognitive deficit in aged rats by inhibiting the production of inflammatory cytokines.

Evaluation of Effect of Topical Tacrolimus Treatment on Herpetic Stromal Keratitis in a Rat Model.

OBJECTIVES: To investigate the effectiveness of topical tacrolimus treatment on herpetic stromal keratitis (HSK) in a rat model. METHODS: The development of HSK was monitored for 14 days after the inoculation of rats with herpes simplex type 1 virus. Rats that developed HSK were divided into four groups as follows: (1) topical antiviral treatment (control), (2) topical antiviral and 1% prednisolone acetate, (3) topical antiviral and 0.03% tacrolimus ointment, and (4) topical antiviral plus 0.1% tacrolimus ointment. After 14 days of treatment, the severity levels of HSK were scored and compared with the levels before the treatment. The expression of CD3, CD4, and CD8 was evaluated by flow cytometry. The development of the disease was evaluated clinically and histologically. RESULTS: Significant improvement in vascularization was observed in the groups with the drug treatment in addition to the antiviral agent (P<0.05), but there was no obvious difference within groups 2, 3, and 4 in the vascularization severity. The regression of corneal edema was 8.05%±6% in group 1, 25.17%±14.55% in group 2 (P=0.01), 36.40%±21.69% in group 3 (P=0.03), and 46.39%±14.96% in group 4 (P=0.00). A significant decrease in the number of inflammatory cells in the groups with the drug treatment was evaluated by immunohistochemical staining and confirmed by flow cytometry analysis. CONCLUSIONS: Topical tacrolimus treatment caused a significant decrease in corneal vascularization accompanied by a lower number of inflammatory cells in the experimental HSK corneal edema model. Therefore, topical tacrolimus has the potential to be used in the treatment of HSK.

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.

Phenotypic and proteomic characteristics of human dental pulp derived mesenchymal stem cells from a natal, an exfoliated deciduous, and an impacted third molar tooth.

The level of heterogeneity among the isolated stem cells makes them less valuable for clinical use. The purpose of this study was to understand the level of heterogeneity among human dental pulp derived mesenchymal stem cells by using basic cell biology and proteomic approaches. The cells were isolated from a natal (NDPSCs), an exfoliated deciduous (stem cells from human exfoliated deciduous (SHED)), and an impacted third molar (DPSCs) tooth of three different donors. All three stem cells displayed similar features related to morphology, proliferation rates, expression of various cell surface markers, and differentiation potentials into adipocytes, osteocytes, and chondrocytes. Furthermore, using 2DE approach coupled with MALDI-TOF/TOF, we have generated a common 2DE profile for all three stem cells. We found that 62.3 ± 7% of the protein spots were conserved among the three mesenchymal stem cell lines. Sixty-one of these conserved spots were identified by MALDI-TOF/TOF analysis. Classification of the identified proteins based on biological function revealed that structurally important proteins and proteins that are involved in protein folding machinery are predominantly expressed by all three stem cell lines. Some of these proteins may hold importance in understanding specific properties of human dental pulp derived mesenchymal stem cells.

In vitro protection of adipose tissue-derived mesenchymal stem cells by erythropoietin.

Mobilization of stem cells and their differentiation into cardiomyocytes are known to have protective effects after myocardial infarction. The integrity of transplanted mesenchymal stem cells for cardiac regeneration is dependent on cell-cell or cell-matrix interaction, which is adversely affected by reactive oxygen species in an ischemic environment. Treatment with erythropoietin was shown to protect human adipose tissue derived mesenchymal stem cells in an ischemic injury in vitro model. The analyses indicated that expression of erythropoietin receptors played a pivotal role in erythropoietin mediated cell survival. In this study, the anti-apoptotic effect of erythropoietin on stem cells was analyzed in apoptosis-induced human mesenchymal stem cells. Apoptosis was induced in cultured adult human adipose tissue derived mesenchymal stem cells by hydrogen peroxide. A group of cultured cells was also treated with recombinant human erythropoietin in a concentration of 50 ng mL(-1). The degree of apoptosis was analyzed by flow-cytometry and immunohistochemical staining for Caspase 3. The average percentages of apoptotic cells were significantly higher in H2O2-induced stem cells than in cells co-cultured with erythropoietin (63.03 ± 4.96% vs 29 ± 3.41%, p<0.01). We conclude that preconditioning with erythropoietin suppresses apoptosis of mesenchymal stem cells and enhances their survival.

The short- and long- term effects of estrogen deficiency on apoptosis in musculoskeletal tissues: an experimental animal model study.

BACKGROUND: Estrogen is the major sex steroid affecting the growth, remodeling, and homeostasis of the female skeleton. Estrogen loss in postmenopausal women leads to osteoporosis. The aim of this study was to evaluate the early and long- term effects of estrogen loss on bones, tendons, muscles, and menisci in ovariectomized rats.  METHODS: Fifteen rats were randomized into three groups of five animals each. The first group was the control group with no additional surgical procedure, but the rest (groups 2 and 3) were bilaterally ovariectomized . All animals in the group 2 were sacrificed at 14th week to evaluate the short- term effect, and all of other animals in the groups 1 and 3 were sacrificed at 28th week to analyze the long- term effect of estrogen loss in the ovariectomized group and to control with the group 1. Quadriceps muscles, Achilles tendons, menisci, and femur cortical bones from both lower extremities were taken. The amount of apoptosis was measured. RESULTS: There was a significant increase in cell apoptosis in bones, muscles, and tendons with insignificant increase in cell apoptosis in menisci at early and late periods in rats with ovariectomies than the control.  CONCLUSION: The results indicated that estrogen loss after ovariectomy does not only affect bones; it may also increase cell apoptosis in different tissues such as muscles, tendons, and menisci.