Improving outcomes of acute kidney injury using mouse renal progenitor cells alone or in combination with erythropoietin or suramin
© Han et al.; licensee BioMed Central Ltd. 2013
Received: 11 January 2013
Accepted: 10 June 2013
Published: 18 June 2013
So far, no effective therapy is available for acute kidney injury (AKI), a common and serious complication with high morbidity and mortality. Interest has recently been focused on the potential therapeutic effect of mouse adult renal progenitor cells (MRPC), erythropoietin (EPO) and suramin in the recovery of ischemia-induced AKI. The aim of the present study is to compare MRPC with MRPC/EPO or MRPC/suramin concomitantly in the treatment of a mouse model of ischemia/reperfusion (I/R) AKI.
MRPC were isolated from adult C57BL/6-gfp mice. Male C57BL/6 mice (eight-weeks old, n = 72) were used for the I/R AKI model. Serum creatinine (Cr), blood urea nitrogen (BUN) and renal histology were detected in MRPC-, MRPC/EPO-, MRPC/suramin- and PBS-treated I/R AKI mice. E-cadherin, CD34 and GFP protein expression was assessed by immunohistochemical assay.
MRPC exhibited characteristics consistent with renal stem cells. The features of MRPC were manifested by Pax-2, Oct-4, vimentin, α-smooth muscle actin positive, and E-cadherin negative, distinguished from mesenchymal stem cells (MSC) by expression of CD34 and Sca-1. The plasticity of MRPC was shown by the ability to differentiate into osteoblasts and lipocytes in vitro. Injection of MRPC, especially MRPC/EPO and MRPC/suramin in I/R AKI mice attenuated renal damage with a decrease of the necrotic injury, peak plasma Cr and BUN. Furthermore, seven days after the injury, MRPC/EPO or MRPC/suramin formed more CD34+ and E-cadherin+ cells than MRPC alone.
These results suggest that MRPC, in particular MRPC/EPO or MRPC/suramin, promote renal repair after injury and may be a promising therapeutic strategy.
KeywordsAdult kidney stem cell Cell therapy Erythropoietin Suramin
Acute kidney injury (AKI) mainly develops following ischemic or toxic insults and is characterized by acute tubular injury and renal dysfunction [1, 2]. Modern dialysis techniques, such as intermittent or continuous renal replacement therapy, are used in the treatment of AKI, but the syndrome is still characterized by a high mortality and morbidity rate . Thus, it is urgent for us to identify new drugs and find novel therapeutic strategies.
Recently, stem cell therapy has been proposed as a promising alternative in the treatment of AKI [4–8], due to the highly versatile response of cells to their environment. The potential use of stem cells in regenerative medicine to treat kidney diseases represents a critical clinical goal . Mounting evidence indicates that stem cells from different sources have therapeutic potential for AKI, including bone marrow-derived stem cells [4–7], embryonic stem cells, induced pluripotent stem cells, human amniotic fluid stem cells , human cord-blood stem cells  and resident renal stem cells . Among these stem cells, little is known about renal stem cells in the treatment of AKI, because their localization, markers, function and mechanism are still not fully understood. Recent study focuses on an important role of renal stem cells in the treatment of AKI by the mechanism of differentiating into renal tubule cells [12–14]. Especially, mouse renal stem cells accelerate renal regeneration and prolong survival after AKI by differentiating into renal tubule cells and vessel endothelial cells with the expression of E-cadherin and CD34 . This potentially gives a clue to the development of regenerative medicine in the treatment of human renal diseases. Although many efforts have been made to investigate renal stem cells in the treatment of AKI, therapy with renal stem cells for AKI treatment needs more research.
Besides stem cell-based therapy, drug therapy is also applied in the recovery of renal ischemia/reperfusion (I/R) injury. Thus, exploring new drugs or novel pharmacological effects of known drugs in the treatment of AKI is urgent. Recently, erythropoietin (EPO) and suramin were intensely studied in the treatment of AKI for their novel pharmacological effect. EPO may have tissue-protective properties in addition to its well-known erythropoietic function . Song YR et al.  report that preventive administration of EPO could prevent AKI and improve postoperative renal function. EPO may preserve kidney integrity and reinforce the regeneration of tubular epithelium by anti-apoptotic and anti-inflammatory features . Suramin, a polysulfonated naphthylurea usually given in humans in the treatment of trypanosomiasis, is reported to accelerate recovery from renal dysfunction caused by IR injury in mice [19, 20]. The mechanisms remain incompletely understood and may be related to prevention of apoptosis, inhibition of inflammatory cytokine generation and facilitating epithelial cell hyperplasia .
In this study, we explored the different effects of mouse adult renal progenital cells (MRPC) alone or MRPC/EPO or MRPC/suramin in the treatment of AKI. Mouse renal MRPC which were isolated from adult GFP mice, possessed features consistent with renal stem cells. Injection of these MRPC, MRPC/EPO, or MRPC/suramin could rescue renal damage in I/R AKI C57BL/6 mice, followed by formation of CD34+ and E-cadherin+ cells. More pronounced protection of renal function was found in mice treated with MRPC/EPO or MRPC/suramin. Thus, MRPC, particularly MRPC/EPO or MRPC/suramin, might be a promising therapeutic target for the treatment of AKI.
Experiments were carried out on 72 male C57BL/6 mice, with weights ranging from 27 to 32 g at the time of ischemia. C57BL/6-gfp mice were bought from the experimental animal center of the Fourth Military Medical University. All animal procedures were approved by the animal ethics committee of Shandong University (Jinan, China) and followed the Guide for the Care and Use of Laboratory Animals published by the U.S. National Institutes of Health (NIH Publication No. 85–23, revised 1996).
Cell isolation and culture
MRPC were isolated from the renal cortex of eight-week-old C57BL/6-gfp transgenic mice (Fourth Military Medical University, Xian, China) using a previously reported approach [8, 21]. Briefly, the kidney was perfused in vivo with PBS to wash out blood and was then dissected. The renal capsule and medulla tissue were removed and digested with 0.125% type_IV collagenase (Sigma-Aldrich, St Louis, MO, USA) and 0.25% trypsin at 37°C for 30 minutes with gentle shaking. After resuspension in (D)MEM/F12 Sigma-Aldrich), the fraction was filtered through a 200 μm mesh (BD Biosciences, San Jose, CA, USA) to remove undigested tissue, and then a 40 μm mesh was used to remove smaller renal tubules and cell aggregates. The filtered fraction was washed with (D)MEM/F12 containing 10% fetal bovine serum (FBS) (Sigma-Aldrich). To exclude autofluorescence of isolated cells, the level of autofluorescence was detected in similar cell preparations from C57BL/6 mice under a fluorescence microscope. To avoid cell–cell contact, GFP-positive cells were plated at low density (300 cells/cm2) on fibronectin coated culture flasks in the (D)MEM/F12 culture medium containing 10% FBS, 100 U/ml of penicillin, 100 μg/ml of streptomycin, and incubated at 37°C in the presence of 5% CO2.
Characterization of MRPC
Immunocytochemistry of MRPC
Cells growing on a poly-l-lysine coated 24-well plate were washed three times with PBS and fixed in 4% paraformaldehyde for 30 minutes. Cells were permeabilized with 0.1% Triton X-100 PBS for 20 minutes and then blocked with 4% goat serum for one hour. Then cells were incubated with primary antibodies for one hour at room temperature in the absence of sunlight. The following primary antibodies were used: mouse monoclonal anti-Oct-4 (Chemicon, Billerica, MA, USA, MAB4419, 1:200), rabbit polyclonal anti-Pax2 (Covance, Emeryville, CA, USA, PRB-276P, 1:400), rat monoclonal anti-E-cadherin (Chemicon, MABT26, 1:200), mouse polyclonal anti-vimentin (Chemicon, MAB3400, 1:200) and mouse monoclonal anti-alpha smooth muscle actin (α-SMA) antibody (Sigma-Aldrich, A2547, 1:600). After three washes with tris-buffered saline (TBS), cells were incubated with alexa 594-conjugated secondary antibodies (Zhongshan Goldenbridge, China) in PBS. 4,6-Diamino-2-phenyl indole (DAPI) was used for nuclear counterstaining. After washing, slides were mounted with a cover slip in Glycergel Antifade Medium (Dako, Carpinteria, CA, USA). Negative controls were performed using non-immune IgG instead of the primary antibodies. Images were obtained using an Olympus fluorescence microscope. Two independent investigators evaluated the number of Oct-4-, Pax-2-, vimentin- and α-SMA-positive MRPC by counting three randomly selected high-power fields.
Differentiation in vitro
A total of 105 intact cells were plated onto a six-well plate for differentiation of cloned MRPC in vitro. Adipocyte differentiation was induced in (D)MEM/F12 culture medium containing 1-methyl-3-isobutylxanthine, 10-6 M dexamethasone, 10 μg/ml insulin, and stained with saturated Oil-Red O (Sigma-Aldrich) in 60% isopropanol to detect oil droplets two weeks later . Osteogenic differentiation was induced in (D)MEM/F12 culture medium containing 50 μg/ml ascorbic acid, 10 mM β-glycerophosphate and 100 nM dexamethasone. Alizarin red staining was used to detect calcium deposition three weeks later .
Reverse transcription PCR
Total RNA was extracted from MRPC or mesenchymal stem cells (MSC) using Trizol Reagent (Invitrogen, Carlsbad, CA, USA) and 2 μg of total RNA was reverse transcribed into cDNA with oligo-dT primer and reverse transcriptase (Fermentas, Vilnius, Lithuania). PCR was performed with specific primer sets at 95°C for 5 minutes, 95°C for 30 seconds, 60°C for 30 seconds, and 72°C for 30 seconds (30 cycles) followed by 72°C for 10 minutes. The forward and reverse primers were designed by Primer 5 for mouse gene: TCC CAG TGT CTC ATC CAT CA (forward primer) and GTT AGA GGC GCT GGA AAC AG (backward primer) for Pax-2, CAC GAG TGG AAA GCA ACT CA (forward primer) and AGA TGG TGG TCT GGC TGA AC (backward primer) for Oct-4, ACC ACA GAC TTC CCC AAC TG (forward primer) and CGG ATT CCA GAG CAT TTG AT (backward primer) for CD34, CCA CCA GGG ACT GAC AAG TT (forward primer) and TGT AAT TTG TTT GGG CAC GA (backward primer) for CD45, CCA TCA ATT ACC TGC CCC TA (forward primer) and TTC CTG GCA ACA GGA AGT CT (backward primer) for Sca-1, ATT TTC TG GGC AGG AAG TT (forward primer) and ACG TCA GAA CAA CCG AAT CC (backward primer) for CD106, CGC TCT CCT GCT CTC AGT CT (forward primer) and GCA CGT GCT TCC TCT TCT CT (backward primer) for CD90, AGA ACT GGA GAA GTG TGG CTG TGA CC (forward primer) and TGT ATG TGG CTT GAA CTG TGC ATT CCG (backward primer) for Wnt-4, ACA TCC GAC TTC CAA GAC AGC ACA C (forward primer) and TTG CAG CCA GAC CTC TGA AAT TCT G (backward primer) for WT-1, and ACG GCA CAG TCA AGG CTG AG (forward primer) and GGA GGC CAT GTA GAC CAT GAG G (backward primer) for glyceraldehyde-3-phosphate dehydrogenase. PCR products were subjected to 2% agarose gel electrophoresis, stained with ethidium bromide, and visualized under UV transilluminator.
Effect of MRPC on renal protection after acute ischemic injury
Twenty-four mice were randomly divided into controls (positive control) or either of the three treatment arms (MRPC, MRPC/EPO or MRPC/suramin). Animals were housed at a constant temperature and humidity, with a 12:12-hour light–dark cycle. At days 0 (pre-ischemia), 1, 2 and 3, blood samples were collected for the measurement of serum creatinine (Cr) and blood urea nitrogen (BUN). Cr and BUN concentrations were detected by the Jaffe method (Beckman Coulter Synchron LX System; Beckman Coulter Inc., Brea, Calif., USA). Then, the mice were sacrificed at day 7. An additional 48 mice were used to observe the early changes in the kidney after injury; 24 mice (n = 6 in each group) were sacrificed at day 2, and the other 24 mice (n = 6 in each group) were sacrificed at day 4. Bilateral kidneys were obtained and fixed with formalin followed by paraffin embedding. Sections were stained with H & E and studied histologically for morphologic changes induced by ischemic injury. A grading scale (range: 0 to 4) for assessment of acute tubular necrosis developed by Jablonski et al. was used for the histopathological assessment of acute ischemic injury . In addition, immunohistochemistry assays were performed with anti-GFP antibodies to detect and localize the infused stem cells in the tissue as well as the expression level of E-cadherin and CD34 after treatment.
Mice were anesthetized with an intraperitoneal injection of phenobarbital (150 μg/g). An abdominal midline incision was made to expose the kidneys and nontraumatic vascular clamps were used to clamp both renal pedicles for 30 minutes at room temperature. After visual reflow of both kidneys, 50 μl of cell suspensions containing 5 × 105 MRPC in PBS or MRPC/EPO (administration of 5 × 105 MRPC in 50 μl PBS and 1 μg/kg of EPO) or MSC/suramin (administration of 5 × 105 MRPC in 50 μl PBS and 1 mg/kg of suramin) were injected immediately and slowly through the tail vein after surgery. Mice in the control group received 50 μl of PBS only.
Fixed mouse kidney consecutive sections were deparaffinized in xylene and rehydrated through a graded ethanol series to water. After blocking with 4% normal goat serum in PBS, the slides were incubated with primary antibodies overnight at 4°C, biotinylated secondary antibody for 20 minutes. The following primary antibodies were used: rat monoclonal anti-E-cadherin (Chemicon, MABT26, 1:200), rat monoclonal anti-CD34 (Abcam, Cambridge, MA, USA, AB8158, 1:500) and mouse monoclonal anti-GFP (Chemicon, MAB3580, 1:1000).
Data are shown as means ± SD. Comparison between groups was evaluated by two-way analysis of variance (ANOVA) or unpaired t test. P <0.05 was considered statistically significant.
Isolation and culture of fluorescent MRPC
Expression of renal progenitor cell markers in MRPC
MRPC expressed Oct-4, Pax-2, α-SMA and vimentin but not E-cadherin as shown by the immunocytochemistry assay (Figure 1B). Furthermore, MSC from the bone marrow of C57BL/6 mice (mMSC) were isolated to identify the different phenotypes between mMSC with MRPC. Many markers of renal progenitors were expressed in MRPC but not mMSC as assessed by RT-PCR, including Oct-4, Pax-2, Wnt-4 and WT-1. However, CD-34 and Sca-1 were expressed in mMSC but not MRPC (Figure 1C). These results indicated that MRPC are kidney progenitor cells.
Differentiation potential of MRPC
The in vitro differentiation capacity of MRPC was examined to investigate further the potency of MRPC. When induced by osteogenic differentiation medium, MRPC stained positive with Alizarin Red, indicating that they underwent osteogenic differentiation in vitro (Figure 1D). MRPC treated with adipogenic differentiation medium showed the presence of adipocyte morphology with positive staining for Oil-Red O (Figure 1D), which indicated their ability for adipocyte differentiation. Taken together, multi-differentiation function in vitro showed that MRPC were pluripotent.
Therapeutic effect of MRPC alone, MRPC/EPO or MRPC/suramin in I/R AKI mice
Besides a better preservation of renal structure, improvement of renal function was observed in MRPC-, especially MRPC/EPO- and MRPC/suramin-treated mice. Serum Cr and BUN levels were measured in the treatment groups and positive controls at day 0, 1, 2 and 3. Cr and BUN reached their peak levels at day 2 of renal I/R injury in all groups. However, significantly lower levels of Cr were detected in treatment groups, especially MRPC/EPO- and MRPC/suramin-treated mice, compared to that of the positive control at day 1, 2 and 3 (Figure 2P). Taken together, MRPC alone, MRPC/EPO and MRPC/suramin were more effective in improving kidney structure and function of I/R AKI mice; MRPC/EPO and MRPC/suramin had more therapeutic effects than MRPC alone.
Localization and roles of MRPC, MRPC/EPO and MRPC/suramin in mice with AKI
Ischemic reperfusion injury is one of the main causes of AKI and more attention has been focused on stem cell therapy for ameliorating this injury. There has been mounting evidence for the existence of stem cells in the adult kidney, including the glomerulus , interstitium [21, 24–26], tubules [8, 27], and papilla . In this paper we demonstrated protective roles of MRPC, MRPC/EPO and MRPC/suramin after injection in I/R AKI C57BL/6 mice. MRPC, spindle-shaped with a large nucleus, were purified from the kidneys of adult C57BL/6-gfp mice (see Additional file 1 and Additional file 2: Figure S2). They exhibited features of renal progenitor cells with expression of renal progenitor markers Oct-4 and Pax-2, Wnt-4 and WT-1, which are expressed in the renal progenitors of metanephric mesenchyme during embryonic development . MRPC possessed the mesenchymal markers vimentin and α-SMA but not the epithelial marker E-cadherin. Furthermore, there was no expression of hematogenous or endothelial progenitor cell markers in MRPC, such as CD45 or CD34, which negated the possibility that MRPC originated from extrarenal tissues. In addition, MRPC were multipotent for their differentiation into osteoblast and adipocyte lineages in vitro and in vivo (see Additional file 1 and Additional file 3: Figure S3). Moreover, we studied the roles of MRPC alone and in combination with EPO or suramin in the I/R AKI mice model. In agreement with previous studies that showed that MKPC accelerate renal regeneration and prolong survival after ischemic injury [15, 21], these findings identify a suitable cell population, MRPC, for possible use in future studies of cell therapy for AKI. Here, we found that the effect of MRPC/EPO or MRPC/suramin was considerably stronger than MRPC alone very early (day 2) after injection. However, MRPC alone played a sustaining renal regeneration role in I/R AKI C57BL/6 mice. The reasons for this difference still remain to be clarified. A possible explanation is MRPC/EPO or MRPC/suramin formed more CD34+ and E-cadherin+ cells with fast incorporation into renal tubules and capillaries than MRPC alone, consistent with differentiation mechanisms that some MKPC formed vessels with red blood cells inside (CD34+ cells) and some incorporated into renal tubules (E-cadherin+ cells) .
However, MRPC alone played a sustaining renal regeneration role in I/R AKI C57BL/6 mice. The reasons for this still remain to be clarified. It is interesting that whether MRPC homed to the injured region. Our results showed that, seven days after ischemic injury and MRPC injection, GFP fluorescence was detected in some tubules of the kidney by immunofluorescence. One possible explanation may be based on the damaged vascular system in I/R AKI C57BL/6 mice. Acute ischemic injury of the kidney induced hypoxia in the injured region and, therefore, upregulated the expression of SDF-1 which attracted CXCR4+ cells (MRPC) to mobilize to the injured region . As the renal protection effect of MRPC was fast and immediate, there may be many mechanisms involved in the recovery process. Reduction of the inflammatory response was considered as a possible mechanism in the treatment of AKI. It was found that MRPC reduced the post-ischemic inflammatory response and obviously decreased macrophage infiltration, especially when combined with EPO or suramin (see Additional file 1 and Additional file 4: Figure S4).
How MRPC combine with EPO or suramin in the treatment of AKI is still not fully understood. As we know, EPO, a glycoprotein hormone, can stimulate the formation and differentiation of erythroid precursor cells in the bone marrow. However, further studies have been done on the undiscovered roles of EPO on other cell types that express EPO receptors [31–33]. Recent studies have shown that there are EPO receptors on the surfaces of tubular epithelial cells [31, 34]. Furthermore, EPO plays an important role in these cells to protect kidneys against acute injury in animal studies [31–33, 35]. Mechanisms involved in this protection appear to be associated with anti-apoptotic, anti-oxidative and anti-inflammatory properties as well as with the proangiogenic potential of EPO . It was reported that rhEPO treatment significantly attenuated the upregulation of transforming growth factor 1 (TGF-1) and α-SMA and the downregulation of E-cadherin in the obstructed kidney in a mouse model . Further, EPO treatment can increase the expression of CD34  after adriamycin-induced kidney injury. Moreover, E-cadherin is highly positively regulated by EPO in a PI3K-dependent manner in CD34+ progenitor cells . These findings may explain the greater improvement in renal histology and function in the mice treated with MRPC/EPO than in those treated with MRPC alone very early after injection. Suramin, a common drug in the treatment of trypanosomiasis, has recently been found to be useful in accelerating kidney recovery after AKI although the exact mechanism is still incompletely known. Recently, it was reported that the death of renal epithelial cells could directly cause necrosis of renal fibroblasts by releasing ATP immediately into the interstitium of the kidney as a death factor and the P2X7 receptor as a crucial mediator . Since peritubular fibroblasts in the kidney are the major EPO-producing cells, inhibition of P2X7 may promote renal structural and functional recovery after AKI. Since suramin is a general P2 inhibitor, it can inhibit the P2X7 receptor to prevent the death of renal fibroblasts and then raise the EPO level during the AKI process. Thus, suramin may protect against kidney injury by increasing EPO production. There is a close intrinsic correlation between EPO and suramin. However, it is still unclear how MRPC combine with EPO or suramin in the treatment of AKI and advanced research work needs to be done.
Recently, some studies have proven that the therapeutic efficiency of MSC in AKI and many other diseases may be improved by combination with a molecular treatment. La Manna et al.  showed that hyaluronan monoesters with butyric acid (HB) act as a preconditioning agent increasing angiogenesis and vascular regeneration efficiency of FMhMSCs. Mias et al.  found that pretreatment with melatonin could increase the survival, paracrine activity and efficiency of MSCs. Similarly, the protective effects of EPO compounds and MSC combinations are supported by a study which evaluated the effect of this combination on a rat model of ischemia . Although these data are from MSC, it is still reasonable to speculate that the efficiency of MRPC may also be enhanced by combination with molecular treatment. Our data show that MRPC treatment was an efficient approach for recovery from injury. There was no teratoma formed in the kidney six weeks after MRPC injection (see Additional file 1), and there are currently no reports about tumor genesis originating from MRPC. Moreover, our data show that combined MRPC/EPO and MRPC/suramin treatment was a more efficient approach for recovery from injury than MRPC alone very early (day 2) after injection and that MRPC alone played a sustaining renal repair role in I/R AKI C57BL/6 mice. Even though this potentiated effect might be related to the addition of independent beneficial effects of the treatment agents, combination of stem cell-based therapy with pharmacy therapy might offer a novel therapeutic approach for the treatment of I/R-induced AKI in humans.
Taken together, our data suggest that MRPC, generated from the kidney of C57BL/6-gfp mice, might provide a new approach for the treatment of AKI in an in vivo model of acute kidney injury. Our results also indicate that MRPC/EPO or MRPC/suramin provided more beneficial effects very early (day 2) after injection, while MRPC alone played a sustaining role in renal regeneration in the treatment of I/R AKI. These findings suggest that it is feasible to rescue renal damage by the injection of MRPC alone, MRPC/EPO or MRPC/suramin in mice.
Blood urea nitrogen
(Dulbecco’s) modified Eagle’s medium/F12
Fetal bovine serum
Green fluorescent protein
- H & E:
Hematoxylin and eosin
- I/R AKI:
Ischemia/reperfusion acute kidney injury
Mouse kidney progenitor cells
Mouse renal progenitor cells
Mesenchymal stem cells
Reverse transcription polymerase chain reaction
Smooth muscle actin.
The study was supported by grants from The National Natural Science Foundation of China (Project approval number 30840079) and Shandong province science and technology plan (Project approval number 2006GG2202002 and 2008GG10002015).
- Thadhani R, Pascual M, Bonventre JV: Acute renal failure. N Engl J Med. 1996, 334: 1448-1460. 10.1056/NEJM199605303342207.PubMedView Article
- Bonventre JV: Mechanisms of ischemic acute renal failure. Kidney Int. 1993, 43: 1160-1178. 10.1038/ki.1993.163.PubMedView Article
- Xue JL, Daniels F, Star RA, Kimmel PL, Eggers PW, Molitoris BA, Himmelfarb J, Collins AJ: Incidence and mortality of acute renal failure in Medicare beneficiaries, 1992 to 2001. J Am Soc Nephrol. 2006, 17: 1135-1142. 10.1681/ASN.2005060668.PubMedView Article
- Bruno S, Grange C, Deregibus MC, Calogero RA, Saviozzi S, Collino F, Morando L, Busca A, Falda M, Bussolati B, Tetta C, Camussi G: Mesenchymal stem cell-derived microvesicles protect against acute tubular injury. J Am Soc Nephrol. 2009, 20: 1053-1067. 10.1681/ASN.2008070798.PubMedPubMed CentralView Article
- Morigi M, Introna M, Imberti B, Corna D, Abbate M, Rota C, Rottoli D, Benigni A, Perico N, Zoja C, Rambaldi A, Remuzzi A, Remuzzi G: Human bone marrow mesenchymal stem cells accelerate recovery of acute renal injury and prolong survival in mice. Stem Cells. 2008, 26: 2075-2082. 10.1634/stemcells.2007-0795.PubMedView Article
- Tögel F, Weiss K, Yang Y, Hu Z, Zhang P, Westenfelder C: Vasculotropic, paracrine actions of infused mesenchymal stem cells are important to the recovery from acute kidney injury. Am J Renal Physiol. 2007, 292: 1626-1635. 10.1152/ajprenal.00339.2006.View Article
- Semedo P, Correa-Costa M, Antonio Cenedeze M, Maria Avancini Costa Malheiros D, Antonia Dos Reis M, Shimizu MH, Seguro AC, Pacheco-Silva A, Saraiva Camara N: Mesenchymal stem cells attenuate renal fibrosis through immune modulation and remodeling properties in a rat remnant kidney model. Stem Cells. 2009, 27: 3063-3073.PubMed
- Gupta S, Verfaillie C, Chmielewski D, Kren S, Eidman K, Connaire J, Heremans Y, Lund T, Blackstad M, Jiang Y, Luttun A, Rosenberg ME: Isolation and characterization of kidney-derived stem cells. J Am Soc Nephrol. 2006, 17: 3028-3040. 10.1681/ASN.2006030275.PubMedView Article
- Anglani F, Forino M, Del Prete D, Tosetto E, Torregrossa R, D’Angelo A: In search of adult renal stem cells. J Cell Mol Med. 2004, 8: 474-487. 10.1111/j.1582-4934.2004.tb00472.x.PubMedView Article
- Hauser PV, De Fazio R, Bruno S, Sdei S, Grange C, Bussolati B, Benedetto C, Camussi G: Stem cells derived from human amniotic fluid contribute to acute kidney injury recovery. Am J Pathol. 2010, 177: 2011-2021. 10.2353/ajpath.2010.091245.PubMedPubMed CentralView Article
- Morigi M, Rota C, Montemurro T, Montelatici E, Lo Cicero V, Imberti B, Abbate M, Zoja C, Cassis P, Longaretti L, Rebulla P, Introna M, Capelli C, Benigni A, Remuzzi G, Lazzari L: Life-sparing effect of human cord blood-mesenchymal stem cells in experimental acute kidney injury. Stem Cells. 2010, 28: 513-522.PubMed
- Sagrinati C, Netti GS, Mazzinghi B, Lazzeri E, Liotta F, Frosali F, Ronconi E, Meini C, Gacci M, Squecco R, Carini M, Gesualdo L, Francini F, Maggi E, Annunziato F, Lasagni L, Serio M, Romagnani S, Romagnani P: Isolation and characterization of multipotent progenitor cells from the Bowman’s capsule of adult human kidneys. J Am Soc Nephrol. 2006, 17: 2443-2456. 10.1681/ASN.2006010089.PubMedView Article
- Maeshima A, Sakurai H, Nigam SK: Adult kidney tubular cell population showing phenotypic plasticity, tubulogenic capacity, and integration capability into developing kidney. J Am Soc Nephrol. 2006, 17: 188-198.PubMedView Article
- Minuth WW, Denk L, Castrop H: Generation of tubular superstructures by piling of renal stem/progenitor cells. Tissue Eng Part C Methods. 2008, 14: 3-13.PubMedView Article
- Lee PT, Lin HH, Jiang ST, Lu PJ, Chou KJ, Fang HC, Chiou YY, Tang MJ: Mouse kidney progenitor cells accelerate renal regeneration and prolong survival after ischemic injury. Stem Cells. 2010, 28: 573-584.PubMed
- Rathod DB, Salahudeen AK: Nonerythropoietic properties of erythropoietin: implication for tissue protection. J Invest Med. 2011, 59: 1083-1085.
- Song YR, Lee T, You SJ, Chin HJ, Chae DW, Lim C, Park KH, Han S, Kim JH, Na KY: Prevention of acute kidney injury by erythropoietin in patients undergoing coronary artery bypass grafting: a pilot study. Am J Nephrol. 2009, 30: 253-260. 10.1159/000223229.PubMedView Article
- Souza AC, Volpini RA, Shimizu MH, Sanches TR, Camara NO, Semedo P, Rodrigues CE, Seguro AC, Andrade L: Erythropoietin prevents sepsis-related acute kidney injury in rats by inhibiting NF-κB and upregulating endothelial nitric oxide synthase. Am J Physiol Renal Physiol. 2012, 15: 1045-1054.View Article
- Zhuang S, Lu B, Daubert RA, Chavin KD, Wang L, Schnellmann RG: Suramin promotes recovery from renal ischemia/reperfusion injury in mice. Kidney Int. 2009, 75: 304-311. 10.1038/ki.2008.506.PubMedView Article
- Korrapati MC, Shaner BE, Schnellmann RG: Recovery from glycerol-induced acute kidney injury is accelerated by suramin. J Pharmacol Exp Ther. 2012, 341: 126-136. 10.1124/jpet.111.190249.PubMedPubMed CentralView Article
- Bussolati B, Bruno S, Grange C, Buttiglieri S, Deregibus MC, Cantino D, Camussi G: Isolation of renal progenitor cells from adult human kidney. Am J Pathol. 2005, 166: 545-555. 10.1016/S0002-9440(10)62276-6.PubMedPubMed CentralView Article
- Pittenger MF, Mackay AM, Beck SC, Jaiswal RK, Douglas R, Mosca JD, Moorman MA, Simonetti DW, Craig S, Marshak DR: Multilineage potential of adult human mesenchymal stem cells. Science. 1999, 284: 143-147. 10.1126/science.284.5411.143.PubMedView Article
- Jablonski P, Howden BO, Rae DA, Birrell CS, Marshall VC, Tange J: An experimental model for assessment of renal recovery from warm ischemia. Transplantation. 1983, 35: 198-204. 10.1097/00007890-198303000-00002.PubMedView Article
- Dekel B, Zangi L, Shezen E, Reich-Zeliger S, Eventov-Friedman S, Katchman H, Jacob-Hirsch J, Amariglio N, Rechavi G, Margalit R, Reisner Y: Isolation and characterization of nontubular sca-1+lin- multipotent stem/progenitor cells from adult mouse kidney. J Am Soc Nephrol. 2006, 17: 3300-3314. 10.1681/ASN.2005020195.PubMedView Article
- Hishikawa K, Marumo T, Miura S, Nakanishi A, Matsuzaki Y, Shibata K, Ichiyanagi T, Kohike H, Komori T, Takahashi I, Takase O, Imai N, Yoshikawa M, Inowa T, Hayashi M, Nakaki T, Nakauchi H, Okano H, Fujita T: Musculin/MyoR is expressed in kidney side population cells and can regulate their function. J Cell Biol. 2005, 169: 921-928. 10.1083/jcb.200412167.PubMedPubMed CentralView Article
- Chen J, Park HC, Addabbo F, Ni J, Pelger E, Li H, Plotkin M, Goligorsky MS: Kidney-derived mesenchymal stem cells contribute to vasculogenesis, angiogenesis and endothelial repair. Kidney Int. 2008, 74: 879-889. 10.1038/ki.2008.304.PubMedPubMed CentralView Article
- Kitamura S, Yamasaki Y, Kinomura M, Sugaya T, Sugiyama H, Maeshima Y, Makino H: Establishment and characterization of renal progenitor like cells from S3 segment of nephron in rat adult kidney. FASEB J. 2005, 19: 1789-1797. 10.1096/fj.05-3942com.PubMedView Article
- Oliver JA, Maarouf O, Cheema FH, Martens TP, Al-Awqati Q: The renal papilla is a niche for adult kidney stem cells. J Clin Invest. 2004, 114: 795-804.PubMedPubMed CentralView Article
- Vigneau C, Polgar K, Striker G, Elliott J, Hyink D, Weber O, Fehling HJ, Keller G, Burrow C, Wilson P: Mouse embryonic stem cell-derived embryoid bodies generate progenitors that integrate long term into renal proximal tubules in vivo. J Am Soc Nephrol. 2007, 18: 1709-1720. 10.1681/ASN.2006101078.PubMedView Article
- Mazzinghi B, Ronconi E, Lazzeri E, Sagrinati C, Ballerini L, Angelotti ML, Parente E, Mancina R, Netti GS, Becherucci F, Gacci M, Carini M, Gesualdo L, Rotondi M, Maggi E, Lasagni L, Serio M, Romagnani S, Romagnani P: Essential but differential role for CXCR4 and CXCR7 in the therapeutic homing of human renal progenitor cells. J Exp Med. 2008, 205: 479-490. 10.1084/jem.20071903.PubMedPubMed CentralView Article
- Xiao L, Li Z, Xu P, Li Z, Xu J, Yang Z: The expression of EPOR in renal cortex during postnatal development. PLoS One. 2012, 7: e41993-10.1371/journal.pone.0041993.PubMedPubMed CentralView Article
- Westenfelder C: Unexpected renal actions of erythropoietin. Exp Nephrol. 2002, 10: 294-298. 10.1159/000065304.PubMedView Article
- Westenfelder C, Biddle DL, Baranowski RL: Human, rat, and mouse kidney cells express functional erythropoietin receptors. Kidney Int. 1999, 55: 808-820. 10.1046/j.1523-1755.1999.055003808.x.PubMedView Article
- Nakazawa Y, Nishino T, Obata Y, Nakazawa M, Furusu A, Abe K, Miyazaki M, Koji T, Kohno S: Recombinant human erythropoietin attenuates renal tubulointerstitial injury in murine adriamycin-induced nephropathy. J Nephrol. 2013, 26: 527-533. 10.5301/jn.5000178.PubMedView Article
- Sharples EJ, Patel N, Brown P, Stewart K, Mota-Philipe H, Sheaff M, Kieswich J, Allen D, Harwood S, Raftery M, Thiemermann C, Yaqoob MM: Erythropoietin protects the kidney against the injury and dysfunction caused by ischemia-reperfusion. J Am Soc Nephrol. 2004, 15: 2115-2124. 10.1097/01.ASN.0000135059.67385.5D.PubMedView Article
- Park SH, Choi MJ, Song IK, Choi SY, Nam JO, Kim CD, Lee BH, Park RW, Park KM, Kim YJ, Kim IS, Kwon TH, Kim YL: Erythropoietin decreases renal fibrosis in mice with ureteral obstruction: role of inhibiting TGF-beta-induced epithelial-to-mesenchymal transition. J Am Soc Nephrol. 2007, 18: 1497-1507. 10.1681/ASN.2005080866.PubMedView Article
- Modelli de Andrade LG, Viero RM, Cordeiro de Carvalho MF: Treatment of adriamycin-induced nephropathy with erythropoietin and G-CSF. J Nephrol. 2013, 26: 534-539. 10.5301/jn.5000200.PubMedView Article
- Sivertsen EA, Hystad ME, Gutzkow KB, Døsen G, Smeland EB, Blomhoff HK, Myklebust JH: PI3K/Akt-dependent Epo-induced signalling and target genes in human early erythroid progenitor cells. Br J Haematol. 2006, 135: 117-128. 10.1111/j.1365-2141.2006.06252.x.PubMedView Article
- Ponnusamy M, Ma L, Gong R, Pang M, Chin YE, Zhuang S: P2X7 receptors mediate deleterious renal epithelial-fibroblast cross talk. Am J Physiol Renal Physiol. 2011, 300: 62-70. 10.1152/ajprenal.00473.2010.View Article
- La Manna G, Bianchi F, Cappuccilli M, Cenacchi G, Tarantino L, Pasquinelli G, Valente S, Della Bella E, Cantoni S, Claudia C, Neri F, Tsivian M, Nardo B, Ventura C, Stefoni S: Mesenchymal stem cells in renal function recovery after acute kidney injury: use of a differentiating agent in a rat model. Cell Transplant. 2011, 20: 1193-1208. 10.3727/096368910X543394.PubMedView Article
- Mias C, Trouche E, Seguelas MH, Calcagno F, Dignat-George F, Sabatier F, Piercecchi-Marti MD, Daniel L, Bianchi P, Calise D, Bourin P, Parini A, Cussac D: Ex vivo pretreatment with melatonin improves survival, proangiogenic/mitogenic activity, and efficiency of mesenchymal stem cells injected into ischemic kidney. Stem Cells. 2008, 26: 1749-1757. 10.1634/stemcells.2007-1000.PubMedView Article
- Esneault E, Pacary E, Eddi D, Freret T, Tixier E, Toutain J, Touzani O, Schumann-Bard P, Petit E, Roussel S, Bernaudin M: Combined therapeutic strategy using erythropoietin and mesenchymal stem cells potentiates neurogenesis after transient focal cerebral ischemia in rats. J Cereb Blood Flow Metab. 2008, 28: 1552-1563. 10.1038/jcbfm.2008.40.PubMedView Article
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