Bone marrow derived mesenchymal stem cells pretreated with erythropoietin accelerate the repair of acute kidney injury.

BACKGROUND: Mesenchymal stem cells (MSCs) represent a promising treatment option for acute kidney injury (AKI). The main drawbacks of MSCs therapy, including the lack of specific homing after systemic infusion and early cell death in the inflammatory microenvironment, directly affect the therapeutic efficacy of MSCs. Erythropoietin (EPO)-preconditioning of MSCs promotes their therapeutic effect, however, the underlying mechanism remains unknown. In this study, we sought to investigate the efficacy and mechanism of EPO in bone marrow derived mesenchymal stem cells (BMSCs) for AKI treatment. RESULTS: We found that incubation of BMSCs with ischemia/reperfusion(I/R)-induced AKI kidney homogenate supernatant (KHS) caused apoptosis in BMSCs, which was decreased by EPO pretreatment, indicating that EPO protected the cells from apoptosis. Further, we showed that EPO up-regulated silent information regulator 1 (SIRT1) and Bcl-2 expression and down-regulated p53 expression. This effect was partially reversed by SIRT1 siRNA intervention. The anti-apoptotic effect of EPO in pretreated BMSCs may be mediated through the SIRT1 pathway. In a rat AKI model, 24 h after intravenous infusion, GFP-BMSCs were predominantly located in the lungs. However, EPO pretreatment reduced the lung entrapment of BMSCs and increased their distribution in the target organs. AKI rats infused with EPO-BMSCs had significantly lower levels of serum IL-1ß and TNF-α, and a significantly higher level of IL-10 as compared to rats infused with untreated BMSCs. The administration of EPO-BMSCs after reperfusion reduced serum creatinine, blood urea nitrogen, and pathological scores in I/R-AKI rats more effectively than BMSCs treatment did. CONCLUSIONS: Our data suggest that EPO pretreatment enhances the efficacy of BMSCs to improve the renal function and pathological presentation of I/R-AKI rats.

Bone mesenchymal stem cells pretreated with erythropoietin enhance the effect to ameliorate cyclosporine A-induced nephrotoxicity in rats.

An increasing number of experiments and clinical trials have demonstrated the safety, feasibility, and efficacy of mesenchymal stem cells (MSCs)-based therapies for the treatment of various diseases. The main drawbacks of MSC therapy are the lack of specific homing after systemic infusion and early death of injected cells because of the injury micro-environment. We pretreated bone mesenchymal stem cells (BMSCs) with erythropoietin (EPO) to investigate their positive effect on cyclosporine A (CsA)-induced nephrotoxicity. BMSCs were incubated with different concentrations of EPO (10, 100, 500, and 1000 IU/mL) for 24 and 48 h, and their proliferation rate, cytoskeletal morphology, migration ability, and the expression of CXCR4 were evaluated to determine the optimal pretreatment conditions. To investigate the therapeutic effects of BMSCs pretreated with EPO in CsA-induced nephrotoxicity, we established CsA-induced in vitro and in vivo toxicity models. In our in vitro study, preconditioning of BMSCs with 500 IU/mL EPO for 48 h induced a marked increase in their proliferation rate, cytoskeletal rearrangement, migration in the scrape-healing assay, and migration toward injured HK2 cells. In vivo, EPO-BMSCs showed higher ability to improve renal function than BMSCs, and in CsA-induced rats treated with EPO-BMSCs, interstitial lymphocyte infiltration, tubular swelling, necrosis, and interstitial fibrosis decreased. We demonstrated that pretreatment with 500 IU/mL EPO before infusion markedly increased the homing ability of BMSCs, and obviously ameliorate CsA-induced nephrotoxicity in rats.

Rutin ameliorates kidney interstitial fibrosis in rats with obstructive nephropathy.

Rutin reportedly conveys many beneficial effects, including renoprotection; however, it has not yet been demonstrated to have a renoprotective effect against obstructive nephropathy. The present study is the first to show a protective effect of rutin against obstructive renal injury induced by unilateral ureteral obstruction (UUO). A total of 24 male Wistar rats were randomly divided into four groups of six rats each, including vehicle- or rutin-treated sham operated groups, and vehicle- or rutin-treated UUO groups. Rats received daily oral gavage of rutin (100mg/kg) for 2weeks. All rats were euthanized on postoperative day 14. Histological findings showed that rutin administration significantly reduced renal interstitial injury and suppressed interstitial collagen deposits in UUO rats. Moreover, rutin decreased macrophage infiltration, proinflammatory cytokine expression and phosphorylation of nuclear factor-κB p65. Furthermore, rutin inhibited extracellular matrix accumulation by reducing expression of type I/III collagen and fibronectin. Rutin also prevented the epithelial-mesenchymal transition processes of renal tubular cells by decreasing α-smooth muscle actin expression and retaining E-cadherin expression. These effects of rutin were in parallel with the reductions in Smad3 activity and pivotal to the fibrogenic potential of TGF-ß1. Taken together, the renoprotective effects of rutin in obstructive nephropathy were likely due to anti-inflammatory effects and inhibition of TGF-ß1/Smad3 signaling.

Ghrelin attenuates renal fibrosis and inflammation of obstructive nephropathy.

PURPOSE: Ghrelin is a gastric peptide that modulates multiple biological functions, of which the stimulation of food intake is the most well-known function. Ghrelin also exerts potential anti-inflammatory and antifibrotic properties in different organs but to our knowledge whether ghrelin inhibits the progression of renal fibrosis is unknown. Thus, we investigated the effect and underlying mechanisms of ghrelin in a rat model of renal fibrosis. MATERIALS AND METHODS: Male Sprague Dawley® rats were divided into 4 groups, including vehicle or ghrelin treated sham operated groups and vehicle or ghrelin treated unilateral ureteral obstruction groups. Kidneys harvested on postoperative day 7 or 14 were evaluated for renal inflammation, fibrosis and apoptosis, and the expression of profibrotic and proinflammatory factors. RESULTS: Ghrelin inhibited renal fibrosis by attenuating collagen production, extracellular matrix deposition, and α-smooth muscle actin and fibronectin expression. Ghrelin administration decreased macrophage infiltration and several proinflammatory cytokines, including tumor necrosis factor-α, interleukin-1ß and monocyte chemotactic protein-1, as well as phosphorylated nuclear factor-κB p65. Ghrelin also inhibited myofibroblast accumulation by blocking the transforming growth factor-ß1/Smad3 signaling pathway. Furthermore, ghrelin attenuated renal tubular cell apoptosis and epithelial-mesenchymal transition processes induced by unilateral ureteral obstruction injury. CONCLUSIONS: These findings indicate that ghrelin is a potent antifibrotic agent that may have therapeutic potential in patients with obstructive nephropathy.

[Apoptosis induction of rhesus peripheral blood lymphocytes].

OBJECTIVE: To establish a method for inducing apoptosis of rhesus peripheral blood lymphocytes (PBLs). METHODS: Rhesus PBLs were irradiated with X-ray, (60)Co gamma-rays and ultraviolet (UVC254 nm), respectively, and the cell apoptosis was evaluated with flow cytometry using annexin-V staining and propidium iodide staining. RESULTS: X-ray and (60)Co gamma-ray irradiation induced only low apoptotic rates of the PBLs, and UVC resulted in the highest apoptotic rate of about 60%. UVC irradiation of the PBLs in RPMI supplemented with 10% heat-inactivated fetal calf serum for 60 min at a distance of 20 cm led to an early apoptotic rate of 58.85% and necrotic rate of 11.5%. The apoptotic rate of PBLs increased in a dose- and time-dependent fashion. CONCLUSION: For inducing apoptosis of the rhesus PBLs, UVC can be more effective than X-ray and (60)Co gamma-ray. The highest apoptotic rate can be achieved when the rhesus PBLs in RPMI supplemented with 10% heat-inactivated fetal calf serum are exposed to UVC for 60 min at the distance of 20 cm.

[Half-dose Zenapax for acute rejection prevention after renal transplantation].

OBJECTIVE: To investigate the efficacy and safety of half-dose Zenapax for prevention of acute rejection after renal transplantation. METHODS: According to the immunosuppressive regimen and renal function after transplantation, patients were divided into 4 groups, namely groups A, B, C, and D of 90, 73, 11 and 13 patients, respectively. Blood creatinine measured 1 week after operation was <176.6 micromol/L in groups A and B, and was >353 micromol/L in groups C and D. Patients in groups A and C were given 25 mg Zenapax (0.5 mg/kg) and MMF 0.75 g before operation, and those in groups B and D had only MMF of 0.75 g. All patients were given Pred, CsA and MMF after operation, and the rejection episodes, the time of acute rejection onset, the rate of rejection reversal and complications were analyzed in the time period of 6 months after operation. RESULTS: After the operation, 13 patients (14.4%) developed acute rejection in group A, 18 (24.6%) in group B, 6 (54.5%) in group C and 7 (53.8%) in group D (P<0.01). The incidence of acute rejection in group B was significantly lower than that in groups C and D groups (P<0.01), and the latter two groups had similar incidence. The time of acute rejection onset ranged from 3 to 9 days postoperatively (mean 6.2-/+3.2 days) in group A, significantly delayed as compared with that in group B (range 2-8 days, mean 4.7-/+3.1 days), group C (range 2-7 days, mean 4.3-/+4.2 days) and group D group (range 2-9 days, mean 3.9-/+3.5 days), but the time was similar between groups B, C, and D (P>0.05). All acute rejection cases in group A was reversed, and the rate of reversal was 88.9% (16/18) in group B, 83.3% in group C, and 71.4% in group D. No significant differences were noted in such complications as infection, vascular injuries or gastrointestinal reactions between the 4 groups (P>0.05). CONCLUSION: Zenapax at the dose of 25 mg can safely decrease the risk of acute rejection in patients with good postoperative renal function recovery, but dose not seem effective in patients with delayed graft function recovery.

[Risk factors of acute rejection in sensitized kidney transplant recipients].

OBJECTIVE: To identify the risk factors of acute rejection in sensitized recipients undergoing kidney transplantation. METHODS: The clinical data of 102 sensitized kidney transplant recipients were retrospectively analyzed to evaluate the incidence of acute rejection in relation to panel reactive antibodies (PRA), amino acid residual match, postoperative elevation of PRA level and cytokine genotypes. RESULTS: During the follow-up, acute rejection occurred in totally 33 patients, and the incidence was higher in the recipients with high tumor necrosis factor (TNF)-alpha or high interleukin (IL)-10 producer genotype than in those with low TNF-alpha or low/intermediate IL-10 producer genotype (53.1%, 55.0% vs 22.8%, 20.9%, P(18)0.01 respectively). Acute rejection was even more frequent in the recipients with both high TNF-alpha and high/intermediate IL-10 producer genotypes than in those with low TNF-alpha and IL-10 producer genotype (66.7% vs 10.2%, P<0.01). No relations were found between TGF-beta1, IL-6, IFN-gamma gene polymorphisms and the incidence of acute rejection. The incidence in the recipients with PRA level of more than 40% was also higher than those with lower PRA level (<20%, 53.3% vs 22.7%, P<0.05), and the amino acid residual mismatch with 3-4 MM was responsible for a higher incidence in comparison with a mismatch with 0-1 MM (75.0% vs 24.1%, P<0.01). Postoperative elevation of PRA level also increased the risk of acute rejection (45.4% vs 22.4%, P<0.01). CONCLUSION: TNF-alpha, IL-10 gene polymorphism, PRA, amino acid residual mismatch, and increased postoperative PRA level may significantly influence acute rejection in sensitized kidney transplantation recipient, and preoperative evaluation of these factors may benefit the designing of immunosuppressive protocols for these patients.

Risk factors for graft survival in sensitized recipients of kidney transplantation.

OBJECTIVE: To investigate the independent prognostic factors for graft survival in sensitized recipients undergoing kidney transplantation, so as to identify the individuals at high risk of graft loss before transplantation. METHODS: A retrospective investigation was conducted in 102 sensitized kidney transplant recipients and 31 relative variables were analyzed with SPSS10.0 software. Using log-rank method, the influence of these variables on short- and long-term graft survivals was evaluated, and Kaplan-Meier analysis was performed to estimate the 1-, 3- and 5-year graft survival rates and half-life. Proportional hazards regression analysis (Cox model) was used to assess the relative risks of the potential variables. RESULTS: In the recipients with a mean half-life of 8.9 years, the 1-, 3- and 5-year graft survival rates were 90%, 85%, and 75%, respectively. By log-rank analysis, the factors affecting short- and long-term graft survivals were identified, namely the recipient age, times of transplantation, levels of panel reactive antibody and the post-operative anti-HLA-IgG antibody, HLA mismatch, renal function, time needing for graft function recovery, presence of acute rejection, delay of graft function recovery and infection, which affected the graft survival demonstrated by Cox model multivariate analysis. CONCLUSION: High-quality donor kidney and minimization of the risk factors for graft survival may insure successful kidney transplantation in sensitized recipients.