Acute renal failure is a major clinical problem that affects up to 5% of all hospitalized patients (1
Recent studies suggested the involvement of bone marrow (BM)-derived stem cells in the regeneration of nonhematopoietic tissues. BM-derived cells with an endothelial (2 3 , 4 5 6 , 7
Experimental studies have provided evidence for a limited contribution of BM-derived cells to the injured kidney, perhaps as a direct consequence of the low circulating levels of BM-derived stem cells. A study by Orlic et al. (8 et al. , we mobilized HSC with stem cell factor (SCF) combined with granulocyte colony-stimulating factor (G-CSF), which operate synergistically in inducing egress of HSC from the BM compared with G-CSF alone (9
Here we report that cytokine treatment before renal I/R in mice accelerates renal function recovery compared with controls. The underlying mechanism does not depend on a biologically significant contribution of BM-derived stem cells to the kidney but rather on impaired migration and adhesion of granulocytes into the injured kidney, likely the cause of an initial lower degree of damage.
Materials and Methods Mice Six- to 8-wk-old male and female C57BL/6 mice and transgenic enhanced green fluorescence protein (eGFP) expressing male mice (C57BL/6-TgN[ACTbEGFP]1Osb) were respectively purchased from Charles River (Maastricht, The Netherlands) and Jackson Laboratories (Bar Harbor, ME).
Experimental Procedures Mice were anesthetized by an intraperitoneal injection of 0.08 mg/ml fentanyl-citrate, 2.5 mg/ml fluanison (Janssen Pharmaceuticals, Beerse, Belgium), and 1.25 mg/ml midazolam (Roche, Mijdrecht, The Netherlands). Both renal arteries were clamped for 45 (wild type [WT]) or 75 min (chimeras) followed by reperfusion, as predetermined by using a range of occlusion times. Sham-operated mice received identical treatment except for clamping of the renal arteries. One hour before mice were killed, 5-bromo-2′-deoxyuridine (BrdU; Sigma Chemicals, Zwijndrecht, The Netherlands) was injected intraperitoneally (50 mg/kg body wt). WT mice (n = 10 per group) were killed at 1, 3, 7, and 14 d after ischemia (shams at day 3), and chimeric mice (n = 8 per group) were killed at 1, 7, 14, or 28 d after ischemia (shams at day 7). Blood samples were obtained via heart puncture and transferred to heparin tubes. All experimental procedures were approved by the local Animal Care and Use Committee of our institute.
BM Transplantation Total BM was collected from male eGFP mice by flushing femurs and tibiae with sterile PBS that contained 10% FCS (Invitrogen, Breda, The Netherlands) and penicillin (500 units)/streptomycin (500 μg; Invitrogen). Female C57BL/6 mice were lethally irradiated with two doses of 4.5 Gy, divided by 3 h minimally, using a 137 Cs irradiator (CIS Bio International, Gif, France). After the last irradiation dose, mice received an intravenous injection of 5 × 106 eGFP-BM cells and 2 × 105 female WT spleen cells to induce radioprotection in a total volume of 300 μl/mouse.
Six weeks after transplantation, mice received sterile, acidified water (12 × 10−3 M HCl) that contained 0.16% neomycin sulfate (Sigma Chemicals). Chimeras with donor BM engraftment of 50% or higher received an injection of SCF and G-CSF or saline and were subjected to ischemia.
Cytokine-Induced HSC Mobilization For inducing mobilization, mice received a subcutaneous injection of 50 μg/kg per d recombinant rat SCF and 200 μg/kg per d recombinant human G-CSF in saline (a gift from Amgen, Breda, The Netherlands). Cytokines were administered daily starting 5 d before induction of ischemia up to 3 d afterward (8 n = 8 per group), after which the mice were killed the next day; blood samples were handled as described below.
Antibodies Phycoerythrin-conjugated antibodies to CD11b, Gr-1, and Sca-1 and allophycocyanin-conjugated antibodies to c-Kit and CD62L were purchased from BD Biosciences (Alphen a/d Rijn, The Netherlands), to very late antigen-4 (VLA-4) were purchased from Cymbus, and to CXCR4 were purchased from Chemicon (both in Chandlers Ford, UK). Rabbit anti-GFP antibody was purchased from Molecular Probes (Leiden, The Netherlands), antibody to F4/80 was purchased from Serotec (Oxford, UK), active caspase-3 was purchased from Cell Signaling Technologies (Beverly, MA), α-smooth muscle actin (α-SMA) was purchased from DAKO (Glostrup, Denmark), pan-cytokeratin was purchased from Sigma Chemicals, CD10 was purchased from Neomarkers (Fremont, CA), and osteopontin was purchased from R&D (Abingdon, UK). Secondary antibodies conjugated to horseradish peroxidase or alkaline phosphatase were purchased from DAKO.
Flow Cytometric Analyses White blood cells were counted on a Coulter ACT diff2 (Beckman Coulter, Mijdrecht, The Netherlands). Erythrocytes were lysed in 160 mM NH4 Cl, 10 mM KHCO3 , and 0.1 mM EDTA (pH 7.4). eGFP-BM engraftment efficiency in recipients was determined by analyzing circulating leukocytes for GFP expression. Analysis of adhesion molecules was performed by incubating leukocytes with labeled antibodies for 1 h. Before analysis, cells were fixed in PBS that contained 2% paraformaldehyde. Analyses were performed on a FACSCalibur (Becton Dickinson, Franklin Lakes, NJ).
Histology, Renal Function, and Immunohistochemistry Kidneys were fixed in 10% buffered formalin for 20 h and embedded in paraffin using standard procedures. For examining renal histology, sections (4 μm) were stained with periodic acid-Schiff reagent and hematoxylin. Injury to tubuli was assessed by determining the percentage of affected tubules per 10 fields (magnification, ×400) in the corticomedullary region according to the following criteria: Tubular dilation, epithelial necrosis, cast deposition, and loss of brush border. Injury was graded on a scale from 0 to 5: 0, 0%; 1, <10%; 2, 10 to 25%; 3, 25 to 50%; 4, 50 to 75%; and 5, >75%. For assessing renal function, serum creatinine and urea concentrations were measured by standard diagnostic procedure. For detection of F4/80, active caspase-3, and GFP, sections were boiled in 0.3% citrate buffer (pH 6); for BrdU, sections were treated with 2 M HCl and 0.4% pepsin (Sigma Chemicals). Sections were stained using 3 to 3′ diaminobenzidine dihydrochloride, 3-amino-9-ethylcarbazole, or the Vector Blue Alkaline Phosphatase Substrate Kit III (Vector Laboratories, Peterborough, UK). Counterstaining was performed in a 2% methyl-green solution. For quantifying granulocytes, macrophages, and cellular proliferation (BrdU) or apoptosis of tubular epithelial cells (caspase-3), positive cells were counted per 10 high-power fields (×400) in the corticomedullary region. Osteopontin- and α-SMA-stained sections were analyzed using Image-Pro Plus version 4.5.1 software package from Mediacybernetics (Gleichen, Germany) by determining the percentage of staining in six nonoverlapping fields in the corticomedullary region (×200).
Y Chromosome Fluorescence In Situ Hybridization Detection of y chromosomes was performed on 6-μm cryostat sections, using a mouse Y chromosome-specific FITC-labeled probe (Starfish; Cambio, Cambridge, UK) following the procedure described by Kanazawa et al. (10
ELISA Frozen kidneys were blended in PBS that contained 1% Triton X-100, 1 mM EDTA, and 1% protease inhibitor cocktail II (Sigma Chemicals). Keratinocyte-derived chemokine (KC), IL-1β, and monocyte chemoattractant protein-1 (MCP-1) DuoSet ELISA-kits (R&D Systems) were performed according to the supplied protocols. Cytokine levels were corrected for total protein content per sample using Bio-Rad Protein Assay (Biorad, Veenendaal, The Netherlands).
Statistical Analyses Results are expressed as means ± SEM. Data were analyzed with the nonparametric Mann-Whitney U Test, using SPSS software (SPSS, Inc., Chicago, IL). Values of P ≤ 0.05 were considered statistically significant.
Results Cytokine Treatment Improves Renal Function after I/R Injury To determine whether cytokine-induced HSC mobilization would affect renal function, we subjected mice to bilateral renal ischemia after treatment with either SCF/G-CSF or saline. Analysis of peripheral blood revealed a 15-fold increase in the total number of c-KIT+ Sca-1+ cells in cytokine-treated animals compared with controls (0.34 ± 0.09 versus 0.02 ± 0.01 × 106 cells/ml, respectively). Cytokine treatment led to increased numbers of circulating granulocytes compared with controls (2.31 ± 0.62 versus 0.23 ± 0.08 × 106 cells/ml, respectively) as has previously been reported (11 , 12
Renal function was assessed by the measurement of urea and creatinine in the serum of the animals. One day after ischemia, serum urea (Figure 1a ) and creatinine (Figure 1b ) concentrations increased in both groups, indicating loss of renal function. Three days after the induction of ischemia, the renal function of cytokine-injected mice showed a better improvement than that of control animal. Additional animals (n = 10 per group) were operated on and killed at day 3, resulting in similar outcome (data not shown).
Figure 1.:
Cytokine treatment resulted in earlier recovery of renal function. (a) Serum urea values in cytokine-treated animals (▪) were lower at day 3 after ischemia as compared with controls (□; NS, P = 0.08). (b) Cytokine-treated mice (▪) showed lower serum creatinine levels 3 d (NS, P = 0.06) and 7 d after ischemia (*P = 0.01) compared with controls (□). Data are expressed as mean and SEM.
To correlate these findings to histology (Figure 2a ), we determined the degree of tubular injury by assessing the percentage of damaged tubuli (Figure 2b ). Although cytokine-treated animals showed a lower degree of tubular damage, resembling the course of renal function, no statistically significant differences were found in the percentage and degree of injured tubuli in kidney sections from both the cytokine-treated and control animals. The rate of proliferation of TEC (Figure 3a ), as determined by BrdU incorporation, and apoptosis (Figure 3b ), as determined by staining for active caspase-3, were found not to differ significantly between cytokine-injected and control mice.
Figure 2.:
The progression and resolution of ischemic renal injury and organ reperfusion. Left and right columns display, respectively, representative examples of periodic acid-Schiff-stained kidney tissue sections from saline- and cytokine-treated mice. Ischemia was induced for 45 min by clamping of both renal arteries. (a) Animals were killed, and renal histology was examined. After24 h, tubular dilation in the corticomedullary area was observed as well as migration of inflammatory cells into the interstitium. At the third day after ischemia, injury had progressed and resulted in necrosis of tubular epithelial cells (TEC), leading to denudation of tubuli. One week after induction of ischemia, the normal tissue histology had been replaced by areas of dedifferentiated cell types. Two weeks after the initial ischemic insult, kidney morphology had returned to normal; only few tubules showed signs of minor damage. (b) Semiquantitative scoring of the percentage of damaged tubuli revealed no significant difference in tissue damage between controls (□) and cytokine-treated animals (▪). Data are expressed as mean and SEM.
Figure 3.:
Cytokine treatment in mice (▪) did not affect overall TEC proliferation or apoptosis compared with saline-injected animals (□). (a) No statistically significant differences in the number of 5-bromo-2′-deoxyuridine-positive TEC were observed between both groups at all time points. (b) Similarly, no significant differences were detected in the number of apoptotic TEC present after ischemia between both groups. Data are expressed as mean and SEM.
No Evidence for Cytokine-Induced Increase in BM-Derived Tubular Epithelium after I/R Injury To investigate whether the increase of renal function after cytokine treatment is attributable to the recruitment of BM-derived cells into the kidney after I/R injury, we generated chimeras by syngenic transplantation of male eGFP-expressing BM cells into lethally irradiated female WT recipients. In a pilot experiment, the clamping time needed to induce a degree of injury and renal dysfunction comparable to that induced in the nonirradiated animals was appointed at 75 min (as opposed to 45 min for nonirradiated animals). No significant increase in serum creatinine was detected when clamping times of 45 or 60 min were used, confirmed by the lack of significant histologic indications of injury (data not shown).
One week after ischemia, a large amount of GFP+ cells were observed in kidneys from both groups of mice (Figure 4a ). Because of their peritubular localization, the vast majority of these cells were not recognized as TEC (Figure 4c ) but were mainly leukocytes and myofibroblasts (data not shown). Double immunostainings for GFP and the epithelial marker metalloproteinase CD10 (Figure 4e ) or cytokeratins (Figure 4f ) identified only a few BM-derived TEC in both groups. Sporadically, glomerular epithelial cells of BM origin were detected regardless of the received treatment (Figure 4d ). Two and 4 wk after ischemia, the number of GFP+ cells decreased to levels comparable to sham-operated chimeras, whereas no BM-derived TEC were detected.
Figure 4.:
Detection of bone marrow (BM)-derived cells in the injured kidney of chimeric female mice after ischemia. (a) Low-magnification overview of the renal corticomedullary region from cytokine-treated mice 7 d after ischemia. The renal papilla is indicated by *. Note the extensive influx of BM-derived, green fluorescence protein-positive (GFP+ ) cells stained brown. (b) Fluorescence in situ hybridization for Y chromosome detection in a cytokine-treated mouse 7 d after ischemia. Nuclei were stained with 4′,6-diamidino-2-phenylindole (blue), and actin counterstaining was performed with phalloidin (red). Y chromosome-containing cells (green) with a TEC-like localization (indicated by the arrows) surrounded a dilated tubular lumen filled with cellular debris (*). (c) High magnification of a kidney section stained for GFP (brown) in a control-injected mouse 7 d after ischemia. Most GFP+ cells exhibited a peritubular localization. (d) BM-derived podocytes were detected 7 d after ischemia in a glomerulus. (e and f) Arrows indicate GFP+ cells (red) expressing CD10 (blue; e) or cytokeratin (blue; f) 7 d after ischemia in a cytokine-treated mouse. Magnification, ×20 in a; ×600 in b; ×400 in c through f.
To confirm these findings, we determined the presence of Y chromosomes. In accordance with immunostainings for GFP, few Y chromosome-containing TEC were observed 1 wk after injury (Figure 4b ), and none were detected 4 wk after induction of ischemia, although some clustered peritubular donor-derived cells were found.
Cytokine Treatment Leads to Impaired Granulocyte Migration to the Injured Kidney I/R injury is characterized by the influx of granulocytes that are deleterious for renal function (13–15 Figure 5a ), as assessed by immunostaining (Figures 5, b and c ). At later time points, the number of granulocytes in both groups was found to converge and returned to low, normal levels in both groups of animals (Figure 5a ).
Figure 5.:
Cytokine treatment resulted in impaired granulocyte influx. (a) Kidney sections from cytokine-treated mice (▪) contained fewer granulocytes 1 d after ischemia compared with controls (□; *P = 0.05). Data are expressed as mean and SEM. (b and c) Representative examples of kidney sections from control (b) and cytokine-treated (c) animals stained for granulocytes at 1 d after ischemia. Magnification, ×400.
Cytokine Treatment Results in Impaired Adhesion of Granulocytes but Not of HSC Because G-CSF has been reported to have anti-inflammatory properties, consisting of lowering secretion of proinflammatory cytokines (16
To investigate whether differences in expression of adhesion molecules at the day of injury are responsible for the impaired influx of granulocytes after cytokine treatment, we analyzed granulocytes for expression of L-selectin and CD11b. Circulating granulocytes from cytokine-treated animals showed significant lower expression of L-selectin, whereas expression of CD11b was unaffected compared with controls (Figure 6a ). Likewise, c-KIT+ Sca-1+ cells were examined for expression of CXCR4, CD11b, and VLA-4. In contrast, cytokine treatment did not result in altered expression of the chemokine receptor CXCR4 and the integrins CD11b on VLA-4 by c-KIT+ Sca-1+ cells (Figure 6b ).
Figure 6.:
(a) Five-day cytokine treatment (▪) resulted in significant lower expression of L-selectin (*P = 0.03) but not of CD11b on circulating granulocytes as compared with controls (□). (b) Five-day cytokine treatment (▪) did not significantly affect expression of VLA-4, CXCR4, or CD11b on c-KIT+ Sca-1+ cells compared with controls (□). Data are expressed as mean and SEM.
Cytokine Treatment Leads to Increased Macrophage Influx into the Injured Kidney Because in this study cytokine treatment seemed to affect the migrational potential of leukocytes, we also determined the presence of macrophages. Infiltration of macrophages peaked at 7 d after ischemia and was significantly higher in kidneys from cytokine-injected mice compared with controls (Figure 7a ).
Figure 7.:
Increased macrophage influx after cytokine treatment. (a) Infiltration of kidneys by macrophages was significantly increased in cytokine-treated mice (▪) at day 7 after ischemia as compared with controls (□; *P < 0.05). Representative examples of F4/80 immunostainings of kidney sections from control and cytokine-treated mice 7 d after ischemia. (b) Increased osteopontin staining in the corticomedullary area of the kidney at day 7 after ischemia was observed in cytokine-treated mice (▪) at day 7 after ischemia as compared with controls (□; *P < 0.02). (c) Cytokine treatment induced increased myofibroblast influx after ischemia. Sections were stained for α-smooth muscle actin, and staining was quantified by digital image analysis. Increased staining was observed in cytokine-treated animals (▪) 7 d after ischemia compared with controls (*P = 0.02). Representative examples of stained kidney sections from control and cytokine-treated mice 7 d after ischemia. Data are expressed as mean and SEM. Magnification, ×400 in a and c.
MCP-1 is an important chemokine associated with increased macrophage numbers in kidney diseases (17
Osteopontin is a glycoprotein that is expressed on TEC during I/R injury and also implicated attraction and binding of macrophages (18 , 19 Figure 7b ).
Macrophages are correlated with the progression of fibrosis after renal injury (20 Figure 7c ) as determined by staining for α-SMA.
Discussion Tissue regeneration after injury, based on the contribution by BM-derived stem cells, is thought to offer an attractive and practical solution to organ failure in patients but may be limited by the often low and biologically insignificant involvement of these newly formed stem cell-derived tissue cells to the function of the target organ. SCF- and G-CSF-mediated mobilization has been proposed to present a potential answer by increasing the availability of HSC to the target organ. In a previous study, amelioration of heart function was observed in an experimental model of myocardial ischemia after treatment with SCF and G-CSF (8
Despite the 9.5-fold increase in circulating granulocytes after cytokine treatment, the number of granulocytes present in the injured kidney was reduced by a factor of 3.2 compared with saline-treated mice. This finding is likely to be responsible for the rapid improvement of renal function in mice that were treated with SCF and G-CSF, because postischemic granulocyte recruitment into the kidney has been recognized as a key factor in the early development of acute ischemic renal failure (13 , 21 22 23 24 25 26 15 27 , 28 29 , 30 in vitro (31
A recent report (32 et al. (32
Mobilization of HSC by G-CSF has been shown to be accompanied by downregulation of the integrin VLA-4 and the cytokine receptor CXCR4. We hypothesized that c-KIT+ Sca-1+ cells use an adhesion mechanism comparable to that used in homing of HSC to the BM, which involves VLA-4 (33 34 35 + Sca-1+ cells can take place.
In contrast to impairment of granulocyte migration, we observed an increased macrophage influx in cytokine-treated animals. Macrophage influx during renal injury has been linked to progressive fibrosis by the accumulation of myofibroblasts (20 19 19 in vitro (19
In our study, a small fraction of all TEC was of BM origin in both cytokine-treated and control animals. This is in accordance with previous studies (3 , 4 + cells coexpressing the marker endopeptidase CD10 or forms of cytokeratins and were part of a tubular structure. At later time points after injury, however, no GFP+ TEC were detected. To rule out the possibility that donor-derived cells were overlooked as a result of loss of expression of GFP, we performed fluorescence in situ hybridization for Y chromosomes, which gave similar results. Thus, we conclude that in our model, BM contribution to TEC after injury is only modest and most likely transient. More recent studies concerning the same model used by Orlic et al. (8 36 , 37 38
A surprising feature that arose during a pilot experiment for this study was the increased clamping time of the renal arteries of chimeric animals needed to result in decreased renal function. Full-body ionizing radiation before BM transplantation induces oxidative stress in the exposed kidney (39 40
In light of recent studies concerning the plasticity of HSC, we investigated whether therapy that is based on the increased availability of HSC would provide a potential therapeutic intervention in the treatment of renal I/R injury. Here we show that the beneficial effect of cytokine treatment on renal function after I/R injury is not based on mobilization and increased circulation levels of HSC but rather on decreased granulocyte influx in the damaged kidney. Although we did observe some BM-derived TEC, we do not consider the level of their contribution biologically relevant. Nevertheless, here we described one of the first attempts of stem cell-based therapy using SCF and G-CSF in the treatment of renal I/R injury offering new leads for future studies.
Acknowledgments This work was supported by a grant from The Netherlands Organization for Scientific Research.
We thank Amgen Europe for kindly providing the cytokines.
References 1. Alkhunaizi AM, Schrier RW: Management of acute renal failure: New perspectives.
Am J Kidney Dis 28: 315-328, 1999
2. Rookmaaker MB, Smits AM, Tolboom H, Van 't Wout K, Martens AC, Goldschmeding R, Joles JA, Van Zonneveld AJ, Grone HJ, Rabelink TJ, Verhaar MC: Bone-marrow-derived cells contribute to glomerular endothelial repair in experimental glomerulonephritis.
Am J Pathol 163: 553-562, 2003
3. Kale S, Karihaloo A, Clark PR, Kashgarian M, Krause DS, Cantley LG: Bone marrow stem cells contribute to repair of the ischemically injured renal tubule.
J Clin Invest 112: 42-49, 2003
4. Lin F, Cordes K, Li L, Hood L, Couser WG, Shankland SJ, Igarashi P: Hematopoietic stem cells contribute to the regeneration of renal tubules after renal ischemia-reperfusion injury in mice.
J Am Soc Nephrol 14: 1188-1199, 2003
5. Masuya M, Drake CJ, Fleming PA, Reilly CM, Zeng H, Hill WD, Martin-Studdard A, Hess DC, Ogawa M: Hematopoietic origin of glomerular mesangial cells.
Blood 101: 2215-2218, 2003
6. Gupta S, Verfaillie C, Chmielewski D, Kim Y, Rosenberg ME: A role for extrarenal cells in the regeneration following acute renal failure.
Kidney Int 62: 1285-1290, 2002
7. Poulsom R, Forbes SJ, Hodivala-Dilke K, Ryan E, Wyles S, Navaratnarasah S, Jeffery R, Hunt T, Alison M, Cook T, Pusey C, Wright NA: Bone marrow contributes to renal parenchymal turnover and regeneration.
J Pathol 195: 229-235, 2001
8. Orlic D, Kajstura J, Chimenti S, Limana F, Jakoniuk I, Quaini F, Nadal-Ginard B, Bodine DM, Leri A, Anversa P: Mobilized bone marrow cells repair the infarcted heart, improving function and survival.
Proc Natl Acad Sci U S A 98: 10344-10349, 2001
9. Andrews RG, Briddell RA, Knitter GH, Opie T, Bronsden M, Myerson D, Appelbaum FR, McNiece IK: In vivo synergy between recombinant human stem cell factor and recombinant human granulocyte colony-stimulating factor in baboons enhanced circulation of progenitor cells.
Blood 84: 800-810, 1994
10. Kanazawa Y, Verma IM: Little evidence of bone marrow-derived hepatocytes in the replacement of injured liver.
Proc Natl Acad Sci U S A 100[Suppl 1]: 11850-11853, 2003
11. Morstyn G, Campbell L, Souza LM, Alton NK, Keech J, Green M, Sheridan W, Metcalf D, Fox R: Effect of granulocyte colony stimulating factor on neutropenia induced by cytotoxic chemotherapy.
Lancet 1: 667-672, 1988
12. Molineux G, Migdalska A, Szmitkowski M, Zsebo K, Dexter TM: The effects on hematopoiesis of recombinant stem cell factor (ligand for c-kit) administered in vivo to mice either alone or in combination with granulocyte colony-stimulating factor.
Blood 78: 961-966, 1991
13. Linas SL, Whittenburg D, Parsons PE, Repine JE: Mild renal ischemia activates primed neutrophils to cause acute renal failure.
Kidney Int 42: 610-616, 1992
14. Miura M, Fu X, Zhang QW, Remick DG, Fairchild RL: Neutralization of Gro alpha and macrophage inflammatory protein-2 attenuates renal ischemia/reperfusion injury.
Am J Pathol 159: 2137-2145, 2001
15. Rabb H, Ramirez G, Saba SR, Reynolds D, Xu J, Flavell R, Antonia S: Renal ischemic-reperfusion injury in L-selectin-deficient mice.
Am J Physiol 271: F408-F413, 1996
16. Boneberg EM, Hartung T: Molecular aspects of anti-inflammatory action of G-CSF.
Inflamm Res 51: 119-128, 2002
17. Furuichi K, Wada T, Iwata Y, Kitagawa K, Kobayashi K, Hashimoto H, Ishiwata Y, Asano M, Wang H, Matsushima K, Takeya M, Kuziel WA, Mukaida N, Yokoyama H: CCR2 signaling contributes to ischemia-reperfusion injury in kidney.
J Am Soc Nephrol 14: 2503-2515, 2003
18. Persy VP, Verhulst A, Ysebaert DK, De Greef KE, De Broe ME: Reduced postischemic macrophage infiltration and interstitial fibrosis in osteopontin knockout mice.
Kidney Int 63: 543-553, 2003
19. Xie Y, Sakatsume M, Nishi S, Narita I, Arakawa M, Gejyo F: Expression, roles, receptors, and regulation of osteopontin in the kidney.
Kidney Int 60: 1645-1657, 2001
20. Eddy A: Role of cellular infiltrates in response to proteinuria.
Am J Kidney Dis 37: S25-29, 2001
21. Kelly KJ, Williams WW Jr, Colvin RB, Meehan SM, Springer TA, Gutierrez-Ramos JC, Bonventre JV: Intercellular adhesion molecule-1-deficient mice are protected against ischemic renal injury.
J Clin Invest 97: 1056-1063, 1996
22. Rosen SD: Ligands for L-selectin: Homing, inflammation, and beyond.
Annu Rev Immunol 22: 129-156, 2004
23. Eriksson EE, Xie X, Werr J, Thoren P, Lindbom L: Importance of primary capture and L-selectin-dependent secondary capture in leukocyte accumulation in inflammation and atherosclerosis in vivo.
J Exp Med 194: 205-218, 2001
24. Yadav SS, Howell DN, Gao W, Steeber DA, Harland RC, Clavien PA: L-selectin and ICAM-1 mediate reperfusion injury and neutrophil adhesion in the warm ischemic mouse liver.
Am J Physiol 275: G1341-G1352, 1998
25. Lozano DD, Kahl EA, Wong HP, Stephenson LL, Zamboni WA: L-selectin and leukocyte function in skeletal muscle reperfusion injury.
Arch Surg 134: 1079-1081, 1999
26. Ma XL, Weyrich AS, Lefer DJ, Buerke M, Albertine KH, Kishimoto TK, Lefer AM: Monoclonal antibody to L-selectin attenuates neutrophil accumulation and protects ischemic reperfused cat myocardium.
Circulation 88: 649-658, 1993
27. Rabb H, Mendiola CC, Dietz J, Saba SR, Issekutz TB, Abanilla F, Bonventre JV, Ramirez G: Role of CD11a and CD11b in ischemic acute renal failure in rats.
Am J Physiol 267: F1052-F1058, 1994
28. Tajra LC, Martin X, Margonari J, Blanc-Brunat N, Ishibashi M, Vivier G, Steghens JP, Kawashima H, Miyasaka M, Dubernard JM, Revillard JP: Antibody-induced modulation of the leukocyte CD11b integrin prevents mild but not major renal ischaemic injury.
Nephrol Dial Transplant 15: 1556-1561, 2000
29. Ohsaka A, Saionji K, Sato N, Mori T, Ishimoto K, Inamatsu T: Granulocyte colony-stimulating factor down-regulates the surface expression of the human leucocyte adhesion molecule-1 on human neutrophils in vitro and in vivo.
Br J Haematol 84: 574-580, 1993
30. Jilma B, Hergovich N, Homoncik M, Marsik C, Kreuzer C, Jilma-Stohlawetz P: Rapid down modulation of P-selectin glycoprotein ligand-1 (PSGL-1, CD162) by G-CSF in humans.
Transfusion 42: 328-333, 2002
31. Chakraborty A, Hentzen ER, Seo SM, Smith CW: Granulocyte colony-stimulating factor promotes adhesion of neutrophils.
Am J Physiol Cell Physiol 284: C103-C110, 2003
32. Togel F, Isaac J, Westenfelder C: Hematopoietic stem cell mobilization-associated granulocytosis severely worsens acute renal failure.
J Am Soc Nephrol 15: 1261-1267, 2004
33. Papayannopoulou T, Priestley GV, Nakamoto B, Zafiropoulos V, Scott LM: Molecular pathways in bone marrow homing: Dominant role of alpha(4)beta(1) over beta(2)-integrins and selectins.
Blood 98: 2403-2411, 2001
34. Mohle R, Bautz F, Rafii S, Moore MA, Brugger W, Kanz L: The chemokine receptor CXCR-4 is expressed on CD34+ hematopoietic progenitors and leukemic cells and mediates transendothelial migration induced by stromal cell-derived factor-1.
Blood 91: 4523-4530, 1998
35. Kollet O, Shivtiel S, Chen YQ, Suriawinata J, Thung SN, Dabeva MD, Kahn J, Spiegel A, Dar A, Samira S, Goichberg P, Kalinkovich A, Arenzana-Seisdedos F, Nagler A, Hardan I, Revel M, Shafritz DA, Lapidot T: HGF, SDF-1, and MMP-9 are involved in stress-induced human CD34+ stem cell recruitment to the liver.
J Clin Invest 112: 160-169, 2003
36. Ohtsuka M, Takano H, Zou Y, Toko H, Akazawa H, Qin Y, Suzuki M, Hasegawa H, Nakaya H, Komuro I: Cytokine therapy prevents left ventricular remodeling and dysfunction after myocardial infarction through neovascularization.
FASEB J 18: 851-853, 2004
37. Norol F, Merlet P, Isnard R, Sebillon P, Bonnet N, Cailliot C, Carrion C, Ribeiro M, Charlotte F, Pradeau P, Mayol JF, Peinnequin A, Drouet M, Safsafi K, Vernant JP, Herodin F: Influence of mobilized stem cells on myocardial infarct repair in a nonhuman primate model.
Blood 102: 4361-4368, 2003
38. Nygren JM, Jovinge S, Breitbach M, Sawen P, Roll W, Hescheler J, Taneera J, Fleischmann BK, Jacobsen SE: Bone marrow-derived hematopoietic cells generate cardiomyocytes at a low frequency through cell fusion, but not transdifferentiation.
Nat Med 10: 494-501, 2004
39. Robbins ME, Zhao W, Davis CS, Toyokuni S, Bonsib SM: Radiation-induced kidney injury: A role for chronic oxidative stress?
Micron 33: 133-141, 2002
40. Lee HT, Emala CW: Protective effects of renal ischemic preconditioning and adenosine pretreatment: Role of A(1) and A(3) receptors.
Am J Physiol Renal Physiol 278: F380-F387, 2000
