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Reuter S, Kentrup D, Grabner A, Köhler G, Buscher K, Edemir B. C4d Deposition after Allogeneic Renal Transplantation in Rats Is Involved in Initial Apoptotic Cell Clearance. Cells 2021; 10:3499. [PMID: 34944007 PMCID: PMC8700759 DOI: 10.3390/cells10123499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 12/07/2021] [Accepted: 12/07/2021] [Indexed: 11/16/2022] Open
Abstract
In the context of transplantation, complement activation is associated with poor prognosis and outcome. While complement activation in antibody-mediated rejection is well-known, less is known about complement activation in acute T cell-mediated rejection (TCMR). There is increasing evidence that complement contributes to the clearance of apoptotic debris and tissue repair. In this regard, we have analysed published human kidney biopsy transcriptome data clearly showing upregulated expression of complement factors in TCMR. To clarify whether and how the complement system is activated early during acute TCMR, experimental syngeneic and allogeneic renal transplantations were performed. Using an allogeneic rat renal transplant model, we also observed upregulation of complement factors in TCMR in contrast to healthy kidneys and isograft controls. While staining for C4d was positive, staining with a C3d antibody showed no C3d deposition. FACS analysis of blood showed the absence of alloantibodies that could have explained the C4d deposition. Gene expression pathway analysis showed upregulation of pro-apoptotic factors in TCMR, and apoptotic endothelial cells were detected by ultrastructural analysis. Monocytes/macrophages were found to bind to and phagocytise these apoptotic cells. Therefore, we conclude that early C4d deposition in TCMR may be relevant to the clearance of apoptotic cells.
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Affiliation(s)
- Stefan Reuter
- Department of Internal Medicine D, Experimental Nephrology, University Clinics Münster, 48143 Münster, Germany; (S.R.); (D.K.); (A.G.); (K.B.)
| | - Dominik Kentrup
- Department of Internal Medicine D, Experimental Nephrology, University Clinics Münster, 48143 Münster, Germany; (S.R.); (D.K.); (A.G.); (K.B.)
- Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Alexander Grabner
- Department of Internal Medicine D, Experimental Nephrology, University Clinics Münster, 48143 Münster, Germany; (S.R.); (D.K.); (A.G.); (K.B.)
- Department of Medicine, Division of Nephrology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Gabriele Köhler
- Gerhard Domagk Institute of Pathology, University Clinics Münster, 48143 Münster, Germany;
| | - Konrad Buscher
- Department of Internal Medicine D, Experimental Nephrology, University Clinics Münster, 48143 Münster, Germany; (S.R.); (D.K.); (A.G.); (K.B.)
| | - Bayram Edemir
- Department of Internal Medicine D, Experimental Nephrology, University Clinics Münster, 48143 Münster, Germany; (S.R.); (D.K.); (A.G.); (K.B.)
- Department of Medicine, Hematology and Oncology, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany
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Hypothermic Oxygenated Perfusion: A Simple and Effective Method to Modulate the Immune Response in Kidney Transplantation. Transplantation 2019; 103:e128-e136. [DOI: 10.1097/tp.0000000000002634] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Ayasse N, de Bruijn PIA, Berg P, Sørensen MV, Leipziger J. Hydrochlorothiazide and acute urinary acidification: The "voltage hypothesis" of ENaC-dependent H + secretion refuted. Acta Physiol (Oxf) 2018; 223:e13013. [PMID: 29226589 DOI: 10.1111/apha.13013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 11/20/2017] [Accepted: 12/04/2017] [Indexed: 11/26/2022]
Abstract
AIM The "voltage hypothesis" of H+ secretion states that urinary acidification following increased Na+ delivery to the collecting duct (CD) is ENaC dependent leading to transepithelial voltage-dependent increase in H+ secretion. We recently showed that furosemide acidifies the urine independently of ENaC activity. If the voltage hypothesis holds, hydrochlorothiazide (HCT) must acidify the urine. We here tested the acute effect of HCT on urine pH under normal and high ENaC expression. METHODS Mice subjected to a control or a low-Na+ diet were anesthetized and infused (0.5 mL h-1 ) with saline. Catheterization of the urinary bladder allowed real-time measurement of diuresis and urine pH. Mice received either HCT (1 mg mL-1 ) or vehicle. Urinary Na+ and K+ excretions were determined by flame photometry. ENaC expression levels were measured by semi-quantitative Western blotting. RESULTS (1) HCT increased diuresis and natriuresis in both diet groups. (2) K+ excretion rates increased after HCT administration from 18.6 ± 1.3 to 31.7 ± 2.5 μmol h-1 in the control diet group and from 23.0 ± 1.3 to 48.7 ± 3.0 μmol h-1 in the low-Na+ diet group. (3) Mice fed a low-Na+ diet showed a marked upregulation of ENaC. (4) Importantly, no acute changes in urine pH were observed after the administration of HCT in either group. CONCLUSION Acute administration of HCT has no effect on urine pH. Similarly, substantial functional and molecular upregulation of ENaC did not cause HCT to acutely change urine pH. Thus, an increased Na+ load to the CD does not alter urine pH. This supports our previous finding and likely falsifies the voltage hypothesis of H+ secretion.
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Affiliation(s)
- N. Ayasse
- Department of Biomedicine, Physiology and Biophysics; Aarhus University; Aarhus C Denmark
| | - P. I. A. de Bruijn
- Department of Biomedicine, Physiology and Biophysics; Aarhus University; Aarhus C Denmark
| | - P. Berg
- Department of Biomedicine, Physiology and Biophysics; Aarhus University; Aarhus C Denmark
| | - M. V. Sørensen
- Department of Biomedicine, Physiology and Biophysics; Aarhus University; Aarhus C Denmark
- Aarhus Institute of Advanced Studies; Aarhus University; Aarhus C Denmark
| | - J. Leipziger
- Department of Biomedicine, Physiology and Biophysics; Aarhus University; Aarhus C Denmark
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Klein K, Rübenacker S, Schaefer SM, Kihm LP, Schwenger V, Macher-Goeppinger S, Schemmer P, Süsald C, Zeier M, Morath C, Becker LE. Tissue Expression of Aquaporin 2 Is Correlated to Urine Output and Allograft Function in Sensitized Kidney Transplant Patients. Transplant Proc 2017; 48:2629-2636. [PMID: 27788793 DOI: 10.1016/j.transproceed.2016.06.056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 05/05/2016] [Accepted: 06/06/2016] [Indexed: 01/23/2023]
Abstract
BACKGROUND Salt and water disturbances often occur during acute kidney allograft dysfunction that contribute to graft failure, but this condition has been poorly investigated in the alloreactivity setting. We evaluated the tissue expression of aquaporins (AQP1 and AQP2) and the epithelial sodium channel (ENAC) in kidney biopsy specimens from sensitized kidney transplant recipients. METHODS Eighty-six biopsy specimens from 33 sensitized patients were divided into 3 groups according to clinical context: time-zero (n = 9), protocol (n = 9), and indication (n = 68). The indication biopsy specimens were further divided into 3 subgroups according to the presence of acute tubular necrosis or rejection. Normal kidney tissue samples (n = 6) served as the control specimens. Immmunohistochemical expression of AQP1, AQP2, and ENAC was determined by using image analyzing software. RESULTS Significantly lower AQP1 expression was observed in the time-zero and indication biopsy specimens with rejection compared with control specimens (P = .03 and P = .04, respectively). AQP2 expression was significantly lower in patients with an indication biopsy specimen compared with control and protocol biopsy specimens (P = .05 and P = .005). For ENAC, a lower expression was noted in the indication biopsy specimens compared with the control specimens (P = .04). Both AQP1 and AQP2 tissue expressions were significantly correlated to urine output (r = 0.45 and r = 0.32; P = .001 and P = .02), and AQP2 was correlated with the glomerular filtration rate estimated by using the Modification of Diet in Renal Disease Study equation at biopsy (r = 0.23; P = .05). CONCLUSIONS These findings partially confirm previous experimental data showing downregulation of AQP1 expression after ischemia/reperfusion injury and during rejection. AQP2 downregulation seems to be rejection-independent, occurring during deteriorating or poor kidney graft function.
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Affiliation(s)
- K Klein
- Division of Nephrology, University of Heidelberg, Heidelberg, Germany
| | - S Rübenacker
- Division of Nephrology, University of Heidelberg, Heidelberg, Germany
| | - S M Schaefer
- Division of Nephrology, University of Heidelberg, Heidelberg, Germany
| | - L P Kihm
- Division of Nephrology, University of Heidelberg, Heidelberg, Germany
| | - V Schwenger
- Division of Nephrology, University of Heidelberg, Heidelberg, Germany
| | | | - P Schemmer
- Department of Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
| | - C Süsald
- Department of Transplant Immunology, University of Heidelberg, Heidelberg, Germany
| | - M Zeier
- Division of Nephrology, University of Heidelberg, Heidelberg, Germany
| | - C Morath
- Division of Nephrology, University of Heidelberg, Heidelberg, Germany
| | - L E Becker
- Division of Nephrology, University of Heidelberg, Heidelberg, Germany.
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de Bruijn PIA, Larsen CK, Frische S, Himmerkus N, Praetorius HA, Bleich M, Leipziger J. Furosemide-induced urinary acidification is caused by pronounced H+ secretion in the thick ascending limb. Am J Physiol Renal Physiol 2015; 309:F146-53. [DOI: 10.1152/ajprenal.00154.2015] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The loop diuretic furosemide inhibits NaCl reabsorption in the thick ascending limb (TAL). In addition, furosemide acidifies the urine, which is traditionally explained by increased Na+ loading to the distal tubule causing an activation of H+ secretion via H+-ATPase in α-intercalated cells. The inability to acidify urine in response to furosemide serves to diagnose distal renal tubular acidosis (dysfunction of α-intercalated cells). Since the TAL is important for acid/base regulation, we speculated that it is involved in furosemide-induced urinary acidification. Luminal furosemide (100 μM) caused major, stable, and reversible intracellular alkalization (7.27 ± 0.06 to 7.6 ± 0.04) in isolated perfused murine medullary TAL and pronounced H+ secretion. This H+ secretion was fully inhibited with luminal amiloride (1 mM) and the Na+/H+ exchanger (NHE)3-specific antagonist #4167 (1 μM). Moreover, furosemide triggered a substantial drop of intracellular Na+ concentration in the medullary TAL. These results suggest that the furosemide-induced H+ secretion is a consequence of a drop in intracellular Na+ concentration, increasing the driving force for NHE3. Intriguingly, in whole animal experiments, furosemide-induced urinary acidification and net acid excretion were markedly reduced by specific NHE3 inhibition. Furthermore, the furosemide-induced urinary acidification was partially preserved during epithelial Na+ channel inhibition with benzamil. These results provide new insights in the mechanism of furosemide-induced urinary acidification and emphasize the role of the TAL in renal acid/base handling.
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Affiliation(s)
| | - Casper K. Larsen
- Department of Biomedicine, Physiology, Aarhus University, Aarhus, Denmark; and
| | - Sebastian Frische
- Department of Biomedicine, Physiology, Aarhus University, Aarhus, Denmark; and
| | - Nina Himmerkus
- Institute of Physiology, Christian-Albrechts-University, Kiel, Germany
| | - Helle A. Praetorius
- Department of Biomedicine, Physiology, Aarhus University, Aarhus, Denmark; and
| | - Markus Bleich
- Institute of Physiology, Christian-Albrechts-University, Kiel, Germany
| | - Jens Leipziger
- Department of Biomedicine, Physiology, Aarhus University, Aarhus, Denmark; and
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Bruijn PIA, Bleich M, Praetorius HA, Leipziger J. P2X receptors trigger intracellular alkalization in isolated perfused mouse medullary thick ascending limb. Acta Physiol (Oxf) 2015; 213:277-84. [PMID: 25362991 PMCID: PMC4374443 DOI: 10.1111/apha.12417] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 09/23/2014] [Accepted: 10/24/2014] [Indexed: 02/03/2023]
Abstract
Aims Extracellular ATP is an important regulator of renal tubular transport. Recently, we found that basolateral ATP markedly inhibits Na+ and Cl− absorption in mouse medullary thick ascending limb (mTAL) via a P2X receptor. The underlying mechanism that mediates this ATP-dependent transport inhibition in mTAL is, however, unclear. The renal outer medullary K+ channel (ROMK) is sensitive to intracellular pH where a reduction leads to closing of ROMK. We speculated that P2X receptor stimulation in the TAL could lead to changes in pHi, leading to a reduction in NaCl transport. Methods To test this hypothesis, we measured pHi in single perfused mouse mTALs using the fluorescent ratiometric dye 2′,7′-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethylester. Results Interestingly, basolateral ATP (100 μm) caused a prominent, reversible intracellular alkalization of mTAL, with an average pHi increase of 0.14 ± 0.02 (n = 14). This was completely abolished by the P2X receptor antagonist periodate-oxidized ATP (50 μm). The P2X receptor-mediated intracellular alkalization required the activity of the apical Na+/H+ exchanger (NHE3). Typically, Gq-coupled receptors cause a significant acidification of tubular epithelial cells, which was confirmed in this study, by P2Y2 and Ca2+ sensing receptor stimulation. Conclusion This study reports that stimulation of basolateral P2X receptors causes a substantial intracellular alkalization in the isolated perfused mouse mTAL. This intracellular alkalization is mediated through an increased apical NHE3 activity, similar to what we previously observed when tubular transport is inhibited with furosemide. This increased NHE3 activity causes H+ secretion in the mTAL and provides further support that the TAL is a site of urinary acidification.
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Affiliation(s)
- P. I. A. Bruijn
- Department of Biomedicine, Physiology and Biophysics Aarhus University Aarhus C Denmark
| | - M. Bleich
- Institute of Physiology Christian‐Albrechts‐University Kiel Germany
| | - H. A. Praetorius
- Department of Biomedicine, Physiology and Biophysics Aarhus University Aarhus C Denmark
| | - J. Leipziger
- Department of Biomedicine, Physiology and Biophysics Aarhus University Aarhus C Denmark
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Grabner A, Kentrup D, Schnöckel U, Gabriëls G, Schröter R, Pavenstädt H, Schober O, Schlatter E, Schäfers M, Reuter S. Non-invasive imaging of acute allograft rejection after rat renal transplantation using 18F-FDG PET. J Vis Exp 2013:e4240. [PMID: 23644348 DOI: 10.3791/4240] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The number of patients with end-stage renal disease, and the number of kidney allograft recipients continuously increases. Episodes of acute cellular allograft rejection (AR) are a negative prognostic factor for long-term allograft survival, and its timely diagnosis is crucial for allograft function (1). At present, AR can only be definitely diagnosed by core-needle biopsy, which, as an invasive method, bares significant risk of graft injury or even loss. Moreover, biopsies are not feasible in patients taking anticoagulant drugs and the limited sampling site of this technique may result in false negative results if the AR is focal or patchy. As a consequence, this gave rise to an ongoing search for new AR detection methods, which often has to be done in animals including the use of various transplantation models. Since the early 60s rat renal transplantation is a well-established experimental method for the examination and analysis of AR (2). We herein present in addition small animal positron emission tomography (PET) using (18)F-fluorodeoxyglucose (FDG) to assess AR in an allogeneic uninephrectomized rat renal transplantation model and propose graft FDG-PET imaging as a new option for a non-invasive, specific and early diagnosis of AR also for the human situation (3). Further, this method can be applied for follow-up to improve monitoring of transplant rejection (4).
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Affiliation(s)
- Alexander Grabner
- Department of Internal Medicine D, Experimental Nephrology, University of Münster.
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Girardi ACC, Di Sole F. Deciphering the mechanisms of the Na+/H+ exchanger-3 regulation in organ dysfunction. Am J Physiol Cell Physiol 2012; 302:C1569-87. [DOI: 10.1152/ajpcell.00017.2012] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The Na+/H+ exchanger-3 (NHE3) belongs to the mammalian NHE protein family and catalyzes the electro-neutral exchange of extracellular sodium for intracellular proton across cellular membranes. Its transport function is of essential importance for the maintenance of the body's salt and water homeostasis as well as acid-base balance. Indeed, NHE3 activity is finely regulated by a variety of stimuli, both acutely and chronically, and its transport function is fundamental for a multiplicity of severe and world-wide infection-pathological conditions. This review aims to provide a concise overview of NHE3 physiology and discusses the role of NHE3 in clinical conditions of prominent importance, specifically in hypertension, diabetic nephropathy, heart failure, acute kidney injury, and diarrhea. Study of NHE3 function in models of these diseases has contributed to the deciphering of mechanisms that control the delicate ion balance disrupted in these disorders. The majority of the findings indicate that NHE3 transport function is activated before the onset of hypertension and inhibited thereafter; NHE3 transport function is also upregulated in diabetic nephropathy and heart failure, while it is reported to be downregulated in acute kidney injury and in diarrhea. The molecular mechanisms activated during these pathological conditions to regulate NHE3 transport function are examined with the aim of linking NHE3 dysfunction to the analyzed clinical disorders.
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Affiliation(s)
| | - Francesca Di Sole
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and
- Center of Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
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The reduction of Na/H exchanger-3 protein and transcript expression in acute ischemia-reperfusion injury is mediated by extractable tissue factor(s). Kidney Int 2011; 80:822-831. [PMID: 21814178 DOI: 10.1038/ki.2011.229] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Ischemic renal injury is a formidable clinical problem, the pathophysiology of which is incompletely understood. As the Na/H exchanger-3 (NHE3) mediates the bulk of apical sodium transport and a significant fraction of oxygen consumption in the proximal tubule, we examined mechanisms by which ischemia-reperfusion affects the expression of NHE3. Ischemia-reperfusion dramatically decreased NHE3 protein and mRNA (immunohistochemistry, immunoblot, and RNA blot) in rat kidney cortex and medulla. The decrease in NHE3 protein was uniform throughout all tubules, including those appearing morphologically intact. In the kidney cortex, a decrease in NHE3 surface protein preceded that of NHE3 total protein and mRNA. Kidney homogenates from rats exposed to mild renal ischemia-reduced cell surface NHE3 protein expression in opossum kidney cells in vitro, whereas homogenates from animals with moderate-to-severe ischemia reduced both total NHE3 protein and mRNA. The decrease in total NHE3 protein was dependent on the proteasomal degradation associated with NHE3 ubiquitylation measured by coimmunoprecipitation. The transferable factor(s) from the ischemic homogenate that reduce NHE3 expression were found to be heat sensitive and to be associated with a lipid-enriched fraction, and did not include regulatory RNAs. Thus, transferable factor(s) mediate the ischemia-reperfusion injury-induced decrease in NHE3 of the kidney.
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Reuter S, Schnöckel U, Edemir B, Schröter R, Kentrup D, Pavenstädt H, Schober O, Schlatter E, Gabriëls G, Schäfers M. Potential of noninvasive serial assessment of acute renal allograft rejection by 18F-FDG PET to monitor treatment efficiency. J Nucl Med 2010; 51:1644-52. [PMID: 20847180 DOI: 10.2967/jnumed.110.078550] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED We propose (18)F-FDG PET as a method to monitor acute rejection of allogeneic renal transplants in a rat model. METHODS Allogeneically transplanted (aTX) rats (binephrectomized Lewis-brown Norway to Lewis) served as the renal transplant model. aTX rats treated with cyclosporine A (CSA) served as a therapy monitoring group. Healthy control rats, rats with acute CSA nephrotoxicity, rats with acute tubular necrosis, syngeneically transplanted (sTX) rats, and aTX rats treated with CSA since postoperative day 0 served as controls. After surgery, renal glucose metabolism was assessed in vivo serially up to postoperative day 7 by performing small-animal PET 3 h after intravenous injection of 30 MBq of (18)F-FDG. Mean radioactivity (cps/mm(3) of tissue) was measured and the percentage injected dose calculated. Results were confirmed by histologic, functional, and autoradiographic analysis. RESULTS Renal (18)F-FDG uptake was significantly elevated at postoperative day 4 in aTX rats, when compared with control, sTX, acute tubular necrosis, or CSA-treated rats (P < 0.05). In vivo (18)F-FDG uptake correlated with the results of autoradiography and with inflammatory infiltrates observed on histologic examination. Notably, (18)F-FDG PET assessed the response to therapy 48 h earlier than the time at which serum creatinine decreased and when histologic examination still showed signs of allograft rejection. In aTX rats, the CSA-susceptible graft infiltrate was dominated by activated cytotoxic T cells and monocytes/macrophages. CONCLUSION (18)F-FDG PET is an option to noninvasively assess early response to therapy in rat renal allograft rejection.
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Affiliation(s)
- Stefan Reuter
- Department of Medicine D, Experimental Nephrology, University of Münster, Münster, Germany.
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Reuter S, Reiermann S, Wörner R, Schröter R, Edemir B, Buck F, Henning S, Peter-Katalinic J, Vollenbröker B, Amann K, Pavenstädt H, Schlatter E, Gabriëls G. IF/TA-related metabolic changes--proteome analysis of rat renal allografts. Nephrol Dial Transplant 2010; 25:2492-501. [PMID: 20176611 DOI: 10.1093/ndt/gfq043] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Chronic allograft nephropathy, now more specifically termed interstitial fibrosis and tubular atrophy without evidence of any specific aetiology (IF/TA), is still an important cause of late graft loss. There is no effective therapy for IF/TA, in part due to the disease's multifactorial nature and its incompletely understood pathogenesis. METHODS We used a differential in-gel electrophoresis and mass spectrometry technique to study IF/TA in a renal transplantation model. Dark Agouti (DA) kidneys were allogeneically transplanted to Wistar-Furth (DA-WF, aTX) rats. Syngeneic grafts (DA-DA, sTX) served as controls. Nine weeks after transplantation, blood pressure, renal function and electrolytes were studied, in addition to real-time PCR, western blot analysis, histology and immunohistochemistry. RESULTS In contrast to sTX, the aTX developed IF/TA-dependent renal damage. Ten differentially regulated proteins were identified by 2D gel analysis and mass spectrometry, whereupon five proteins are mainly related to oxidative stress (aldo-keto reductase, peroxiredoxin-1, NAD(+)-dependent isocitrate dehydrogenase, iron-responsive element-binding protein-1 and serum albumin), two participate in cytoskeleton organization (l-plastin and ezrin) and three are assigned to metabolic functions (creatine kinase, ornithine aminotransferase and fructose-1,6-bisphosphatase). CONCLUSION The proteins related to IF/TA and involved in oxidative stress, cytoskeleton organization and metabolic functions may correspond with novel therapeutic targets.
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Affiliation(s)
- Stefan Reuter
- Department of Medicine D, University of Münster, Münster, Germany.
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Reuter S, Schnöckel U, Schröter R, Schober O, Pavenstädt H, Schäfers M, Gabriëls G, Schlatter E. Non-invasive imaging of acute renal allograft rejection in rats using small animal F-FDG-PET. PLoS One 2009; 4:e5296. [PMID: 19390685 PMCID: PMC2669171 DOI: 10.1371/journal.pone.0005296] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Accepted: 03/30/2009] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND At present, renal grafts are the most common solid organ transplants world-wide. Given the importance of renal transplantation and the limitation of available donor kidneys, detailed analysis of factors that affect transplant survival are important. Despite the introduction of new and effective immunosuppressive drugs, acute cellular graft rejection (AR) is still a major risk for graft survival. Nowadays, AR can only be definitively by renal biopsy. However, biopsies carry a risk of renal transplant injury and loss. Most important, they can not be performed in patients taking anticoagulant drugs. METHODOLOGY/PRINCIPAL FINDINGS We present a non-invasive, entirely image-based method to assess AR in an allogeneic rat renal transplantation model using small animal positron emission tomography (PET) and (18)F-fluorodeoxyglucose (FDG). 3 h after i.v. injection of 30 MBq FDG into adult uni-nephrectomized, allogeneically transplanted rats, tissue radioactivity of renal parenchyma was assessed in vivo by a small animal PET-scanner (post operative day (POD) 1,2,4, and 7) and post mortem dissection. The mean radioactivity (cps/mm(3) tissue) as well as the percent injected dose (%ID) was compared between graft and native reference kidney. Results were confirmed by histological and autoradiographic analysis. Healthy rats, rats with acute CSA nephrotoxicity, with acute tubular necrosis, and syngeneically transplanted rats served as controls. FDG-uptake was significantly elevated only in allogeneic grafts from POD 1 on when compared to the native kidney (%ID graft POD 1: 0.54+/-0.06; POD 2: 0.58+/-0.12; POD 4: 0.81+/-0.06; POD 7: 0.77+/-0.1; CTR: 0.22+/-0.01, n = 3-28). Renal FDG-uptake in vivo correlated with the results obtained by micro-autoradiography and the degree of inflammatory infiltrates observed in histology. CONCLUSIONS/SIGNIFICANCE We propose that graft FDG-PET imaging is a new option to non-invasively, specifically, early detect, and follow-up acute renal rejection. This method is potentially useful to improve post-transplant rejection monitoring.
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Affiliation(s)
- Stefan Reuter
- Medizinische Klinik und Poliklinik D, Experimentelle Nephrologie, Universitätsklinikum Münster, Münster, Germany.
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