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Mesenchymal stromal cells (MSCs) are emerging as a novel therapeutic option for limiting chronic kidney disease progression. Conditioned medium (CM) containing bioactive compounds could convey similar benefits, avoiding the potential risks of cell therapy. This study compared the efficacy of nonrenal and renal cell-based therapy with the corresponding CM in rats with renal mass reduction (RMR). Infusions of human kidney stromal cells (kPSCs) and CM-kPSCs, but not umbilical cord (uc) MSCs or CM-ucMSCs, reduced proteinuria and preserved podocyte number and nephrin expression in RMR rats. Glomerular fibrosis, microvascular rarefaction, and apoptosis were reduced by all treatments, while the peritubular microvascular loss was reduced by kPSCs and CM-kPSCs treatment only. Importantly, kPSCs and CM-kPSCs reduced NG2-positive pericytes, and all therapies reduced α-smooth muscle actin expression, indicating reduced myofibroblast expansion. Treatment with kPSCs also significantly inhibited the accumulation of ED1-positive macrophages in the renal interstitium of RMR rats. These findings demonstrate that the CM of ucMSCs and kPSCs confers similar renoprotection as the cells. kPSCs and CM-kPSCs may be superior in attenuating chronic renal injury as a cell source.

Mesenchymal stromal cells (MSCs) are renoprotective and drive regeneration following injury, although cellular targets of such an effect are still ill-defined. Here, we show that human umbilical cord (UC)-MSCs transplanted into mice stimulate tubular cells to regain mitochondrial mass and function, associated with enhanced microtubule-rich projections that appear to mediate mitochondrial trafficking to create a reparative dialogue among adjacent tubular cells. Treatment with UC-MSCs in mice with cisplatin-induced acute kidney injury (AKI) regulates mitochondrial biogenesis in proximal tubuli by enhancing PGC1α expression, NAD+ biosynthesis and Sirtuin 3 (SIRT3) activity, thus fostering antioxidant defenses and ATP production. The functional role of SIRT3 in tubular recovery is highlighted by data that in SIRT3-deficient mice with AKI, UC-MSC treatment fails to induce renoprotection. These data document a previously unrecognized mechanism through which UC-MSCs facilitate renal repair, so as to induce global metabolic reprogramming of damaged tubular cells to sustain energy supply., Mesenchymal stromal cells drive renal regeneration following injury. Here, the authors show that human mesenchymal stromal cells, when transplanted into mice with acute kidney injury, stimulate renal tubular cell growth and enhance mitochondrial function via SIRT3.

Shiga toxin (Stx)-producing Escherichia coli (STEC) infections have become a threat to public health globally because of the severe illnesses that they can trigger, such as hemorrhagic colitis and the post-diarrheal hemolytic uremic syndrome (HUS), characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney failure. Glomerular endothelial cells are primary targets of Stx which, after binding to its specific receptor globotriaosylceramide, upregulates proinflammatory proteins involved both in the recruitment and adhesion of leukocytes and thrombus formation at the site of endothelial injury. In this review, we discuss the role of complement activation in promoting glomerular microvascular dysfunction, providing evidence from experimental models and patients with STEC-HUS. Within the glomerulus, an important target for Stx-induced complement activation is the podocyte, a cell type that is in close contact with endothelial cells and participates in maintaining the filtration barrier. Recently, podocyte injury and loss have been indicated as potential risk factors for long-term renal sequelae in patients with STEC-HUS. Therapeutic approaches targeting the complement system, that may be useful options for patients with STEC-HUS, will also be discussed.

Mesenchymal stem cells (MSCs) of bone marrow origin appear to be an attractive candidate for cell-based therapies. However, the major barrier to the effective implementation of MSC-based therapies is the lack of specific homing of exogenously infused cells and overall the inability to drive them to the diseased or damaged tissue. In order to circumvent these limitations, we developed a preconditioning strategy to optimize MSC migration efficiency and potentiate their beneficial effect at the site of injury. Initially, we screened different molecules by using an in vitro injury–migration setting, and subsequently, we evaluated the effectiveness of the different strategies in mice with acute kidney injury (AKI). Our results showed that preconditioning of MSCs with IGF-1 before infusion improved cell migration capacity and restored normal renal function after AKI. The present study demonstrates that promoting migration of MSCs could increase their therapeutic potential and indicates a new therapeutic paradigm for organ repair.

In nondiabetic rat models of renal disease, angiotensin II (Ang II) perpetuates podocyte injury and promotes progression to end-stage kidney disease. Herein, we wanted to explore the role of Ang II in diabetic nephropathy by a translational approach spanning from in vitro to in vivo rat and human studies, and to dissect the intracellular pathways involved. In isolated perfused rat kidneys and in cultured human podocytes, Ang II down-regulated nephrin expression via Notch1 activation and nuclear translocation of Snail. Hairy enhancer of split-1 was a Notch1-downstream gene effector that activated Snail in cultured podocytes. In vitro changes of the Snail/nephrin axis were similar to those in renal biopsy specimens of Zucker diabetic fatty rats and patients with advanced diabetic nephropathy, and were normalized by pharmacological inhibition of the renin-angiotensin system. Collectively, the present studies provide evidence that Ang II plays a relevant role in perpetuating glomerular injury in experimental and human diabetic nephropathy via persistent activation of Notch1 and Snail signaling in podocytes, eventually resulting in down-regulation of nephrin expression, the integrity of which is crucial for the glomerular filtration barrier.

Podocyte loss is the initial event in the development of glomerulosclerosis, the structural hallmark of progressive proteinuric nephropathies. Understanding mechanisms underlying glomerular injury is the key challenge for identifying novel therapeutic targets. In mice with protein-overload induced by bovine serum albumin (BSA), we evaluated whether the alternative pathway (AP) of complement mediated podocyte depletion and podocyte-dependent parietal epithelial cell (PEC) activation causing glomerulosclerosis. Factor H (Cfh−/−) or factor B-deficient mice were studied in comparison with wild-type (WT) littermates. WT+BSA mice showed podocyte depletion accompanied by glomerular complement C3 and C3a deposits, PEC migration to capillary tuft, proliferation and glomerulosclerosis. These changes were more prominent in Cfh−/− +BSA mice. The pathogenic role of AP was documented by data that factor B deficiency preserved glomerular integrity. In protein-overload mice, PEC dysregulation was associated with upregulation of CXCR4 and GDNF/c-Ret axis. In vitro studies provided additional evidence of a direct action of C3a on proliferation and CXCR4-related migration of PECs. These effects were enhanced by podocyte-derived GDNF. In patients with proteinuric nephropathy, glomerular C3/C3a paralleled PEC activation, CXCR4 and GDNF upregulation. These results indicate that mechanistically uncontrolled AP complement activation is not dispensable for podocyte-dependent PEC activation resulting in glomerulosclerosis.

Generating kidney organoids using human stem cells could offer promising prospects for research and therapeutic purposes. However, no cell-based strategy has generated nephrons displaying an intact three-dimensional epithelial filtering barrier. Here, we generated organoids using murine embryonic kidney cells, and documented that these tissues recapitulated the complex three-dimensional filtering structure of glomerular slits in vivo and accomplished selective glomerular filtration and tubular reabsorption. Exploiting this technology, we mixed human amniotic fluid stem cells with mouse embryonic kidney cells to establish three-dimensional chimeric organoids that engrafted in vivo and grew to form vascularized glomeruli and tubular structures. Human cells contributed to the formation of glomerular structures, differentiated into podocytes with slit diaphragms, and internalized exogenously infused BSA, thus attaining in vivo degrees of specialization and function unprecedented for donor stem cells. In conclusion, human amniotic fluid stem cell chimeric organoids may offer new paths for studying renal development and human podocyte disease, and for facilitating drug discovery and translational research.

Acute kidney injury (AKI) is one of the most relevant health issues, leading to millions of deaths. The magnitude of the phenomenon remarks the urgent need for innovative and effective therapeutic approaches. Cell-based therapy with renal progenitor cells (RPCs) has been proposed as a possible strategy. Studies have shown the feasibility of directing embryonic stem cells or induced Pluripotent Stem Cells (iPSCs) towards nephrogenic intermediate mesoderm and metanephric mesenchyme (MM). However, the functional activity of iPSC-derived RPCs has not been tested in animal models of kidney disease. Here, through an efficient inductive protocol, we directed human iPSCs towards RPCs that robustly engrafted into damaged tubuli and restored renal function and structure in cisplatin-mice with AKI. These results demonstrate that iPSCs are a valuable source of engraftable cells with regenerative activity for kidney disease and create the basis for future applications in stem cell-based therapy.

Background/Aims: Experimental and clinical evidence suggested that monocyte chemoattractant protein-1 (MCP-1/CCL2) has a role in the development of interstitial inflammation and renal failure in polycystic kidney disease (PKD). We investigated whether bindarit, an inhibitor of MCP-1/CCL2 synthesis, could influence the evolution of PKD in PCK rats. Methods: PCK rats were treated from 5 to 15 weeks of age with vehicle or bindarit. Sprague-Dawley rats served as control. For in vitro studies, murine podocytes were exposed to albumin with or without bindarit. Results: MCP-1 mRNA was upregulated in the kidney of PCK rats and reduced by bindarit. Treatment limited overexpression of MCP-1 protein by epithelial cells of dilated tubules and cysts, and interstitial inflammatory cells. Excessive renal accumulation of monocytes/macrophages was lowered by bindarit by 41%. Serum creatinine slightly increased in PCK rats on vehicle and was similar to controls after bindarit. Kidney and liver cysts were not affected by treatment. Bindarit significantly reduced progressive proteinuria of PCK rats. The antiproteinuric effect was associated with the restoration of the defective nephrin expression in podocytes of PCK rats. Bindarit limited podocyte foot process effacement and ameliorated slit diaphragm frequency. In cultured podocytes, bindarit reduced MCP-1 production in response to albumin and inhibited albumin-induced cytoskeletal remodeling and cell migration. Conclusion: This study showed that although bindarit did not prevent renal cyst growth, it limited interstitial inflammation and renal dysfunction and reduced proteinuria in PKD. Thus, bindarit could be considered a therapeutic intervention complementary to therapies specifically acting to block renal cyst growth.

Nitric oxide synthetic capacity in relation to dialysate temperature.Beerenhout CH, Noris M, Kooman JP, Porrati F, Binda E, Morigi M, Bekers O, van der Sande FM, Todeschini M, Macconi D, Leunissen KM, Remuzzi G.Department of Internal Medicine, University Hospital Maastricht, Maastricht, The Netherlands.BACKGROUND: During hemodialysis, vascular reactivity is impaired, which can be corrected by lowering dialysate temperature. It has also been shown that nitric oxide (NO) is related to intradialytic hypotension. As NO synthesis may be temperature-dependent, this study addressed the influence of dialysate temperature on the NO synthetic capacity of plasma. METHODS: NO synthetic capacity was studied during hemodialysis with a dialysate temperature of 37.5 degrees C (dialysis-37.5 degrees C) and programmed extracorporeal blood cooling (cool dialysis; Blood Temperature Monitor; Fresenius C) in 12 stable patients. NO synthetic capacity was assessed ex vivo by [3H]L-citrulline formation from [3H]L-arginine in cultured endothelial cells after incubation with plasma samples obtained during the respective sessions. RESULTS: Core temperature decreased (-0.32 +/- 0.10 degrees C) and energy transfer rate was significantly lower (-27.5 +/- 2.8 W; p < 0.05) during cool dialysis compared to dialysis-37.5 degrees C (0.19 +/- 0.06 degrees C and -0.8 +/- 1.2 W respectively; p < 0.05). Systolic blood pressure decreased during dialysis-37.5 degrees C (-19 +/- 4 mm Hg; p < 0.05), but not during cool dialysis (-6 +/- 5 mm Hg). NO synthetic capacity increased during dialysis-37.5 degrees C (55.5 +/- 9.3 to 73.5 +/- 10.2 pmol/10(5) cells; p < 0.05), in contrast to cool dialysis (67.3 +/- 11.1 to 66.2 +/- 10.8 pmol/10(5) cells). CONCLUSION: The stimulatory effect of uremic plasma on endothelial NO synthesis was augmented during dialysis-37.5 degrees C but not during cool dialysis. Copyright 2004 S. Karger AG, Basel

Shiga toxin (Stx)-producing Escherichia coli is the offending agent of postdiarrhea-associated hemolytic uremic syndrome (HUS), a disorder of glomerular ischemic damage and widespread microvascular thrombosis. We previously documented that Stx induces glomerular complement activation, generating C3a responsible for microvascular thrombosis in experimental HUS. Here, we show that the presence of C3 deposits on podocytes is associated with podocyte damage and loss in HUS mice generated by the coinjection of Stx2 and LPS. Because podocyte adhesion to the glomerular basement membrane is mediated by integrins, the relevance of integrin-linked kinase (ILK) signals in podocyte dysfunction was evaluated. Podocyte expression of ILK increased after the injection of Stx2/LPS and preceded the upregulation of Snail and downregulation of nephrin and α-actinin-4. Factor B deficiency or pretreatment with an inhibitory antibody to factor B protected mice against Stx2/LPS-induced podocyte dysregulation. Similarly, pretreatment with a C3a receptor antagonist limited podocyte loss and changes in ILK, Snail, and α-actinin-4 expression. In cultured podocytes, treatment with C3a reduced α-actinin-4 expression and promoted ILK-dependent nuclear expression of Snail and cell motility. These results suggest that Stx-induced activation of the alternative pathway of complement and generation of C3a promotes ILK signaling, leading to podocyte dysfunction and loss in Stx-HUS.

For chronic kidney diseases, there is little chance that the vast majority of world's population will have access to renal replacement therapy with dialysis or transplantation. Tissue engineering would help to address this shortcoming by regeneration of damaged kidney using naturally occurring scaffolds seeded with precursor renal cells. The aims of the present study were to optimize the production of three-dimensional (3D) rat whole-kidney scaffolds by shortening the duration of organ decellularization process using detergents that avoid nonionic compounds, to investigate integrity of extracellular matrix (ECM) structure and to enhance the efficacy of scaffold cellularization using physiological perfusion method. Intact rat kidneys were successfully decellularized after 17 h perfusion with sodium dodecyl sulfate. The whole-kidney scaffolds preserved the 3D architecture of blood vessels, glomeruli, and tubuli as shown by transmission and scanning electron microscopy. Micro-computerized tomography (micro-CT) scan confirmed integrity, patency, and connection of the vascular network. Collagen IV, laminin, and fibronectin staining of decellularized scaffolds were similar to those of native kidney tissues. After infusion of whole-kidney scaffolds with murine embryonic stem (mES) cells through the renal artery, and pressure-controlled perfusion with recirculating cell medium for 24 and 72 h, seeded cells were almost completely retained into the organ and uniformly distributed in the vascular network and glomerular capillaries without major signs of apoptosis. Occasionally, mES cells reached peritubular capillary and tubular compartment. We observed the loss of cell pluripotency and the start of differentiation toward meso-endodermal lineage. Our findings indicate that, with the proposed optimized protocol, rat kidneys can be efficiently decellularized to produce renal ECM scaffolds in a relatively short time, and rapid recellularization of vascular structures and glomeruli. This experimental setup may open the possibility to obtain differentiation of stem cells with long lasting in vitro perfusion.

Bone marrow-mesenchymal stem cells (BM-MSC) ameliorate renal dysfunction and repair tubular damage of acute kidney injury by locally releasing growth factors, including the insulin-like growth factor-1 (IGF-1). The restricted homing of BM-MSC at the site of injury led us to investigate a possible gene-based communication mechanism between BM-MSC and tubular cells. Human BM-MSC (hBM-MSC) released microparticles and exosomes (Exo) enriched in mRNAs. A selected pattern of transcripts was detected in Exo versus parental cells. Exo expressed the IGF-1 receptor (IGF-1R), but not IGF-1 mRNA, while hBM-MSC contained both mRNAs. R- cells lacking IGF-1R exposed to hBM-MSC-derived Exo acquired the human IGF-1R transcript that was translated in the corresponding protein. Transfer of IGF-1R mRNA from Exo to cisplatin-damaged proximal tubular cells (proximal tubular epithelial cell [PTEC]) increased PTEC proliferation. Coincubation of damaged PTEC with Exo and soluble IGF-1 further enhanced cell proliferation. These findings suggest that horizontal transfer of the mRNA for IGF-1R to tubular cells through Exo potentiates tubular cell sensitivity to locally produced IGF-1 providing a new mechanism underlying the powerful renoprotection of few BM-MSC observed in vivo.

We addressed the role of hyperglycemia in leukocyte-endothelium interaction under flow conditions by exposing human umbilical vein endothelial cells for 24 h to normal (5 mM), high concentration of glucose (30 mM), advanced glycosylation end product-albumin (100 microg/ml), or hyperglycemic (174-316 mg/dl) sera from patients with diabetes and abnormal hemoglobin A1c (8.1+/-1.4%). At the end of incubation endothelial cells were perfused with total leukocyte suspension in a parallel plate flow chamber under laminar flow (1.5 dyn/cm2). Rolling and adherent cells were evaluated by digital image processing. Results showed that 30 mM glucose significantly (P < 0. 01) increased the number of adherent leukocytes to endothelial cells in respect to control (5 mM glucose; 151+/-19 versus 33+/-8 cells/mm2). A similar response was induced by endothelial stimulation with IL-1beta, here used as positive control (195+/-20 cells/mm2). The number of rolling cells on endothelial surface was not affected by high glucose level. Stable adhesion of leukocytes to glucose-treated as well as to IL-1beta-stimulated endothelial cells was preceded by short interaction of leukocytes with the endothelial surface. The distance travelled by leukocytes before arrest on 30 mM glucose, or on IL-1beta-treated endothelial cells, was significantly (P < 0.01) higher than that observed for leukocytes adhering on control endothelium (30 mM glucose: 76.7+/-3.5; IL1beta: 69.7+/-4 versus 5 mM glucose: 21.5+/-5 microm). Functional blocking of E-selectin, intercellular cell adhesion molecule-1, and vascular cell adhesion molecule-1 on endothelial cells with the corresponding mouse mAb significantly inhibited glucose-induced increase in leukocyte adhesion (67+/-16, 83+/-12, 62+/-8 versus 144+/-21 cells/ mm2). Confocal fluorescence microscopy studies showed that 30 mM glucose induced an increase in endothelial surface expression of E-selectin, intercellular cell adhesion molecule-1, and vascular cell adhesion molecule-1. Electrophoretic mobility shift assay of nuclear extracts of human umbilical vein endothelial cells (HUVEC) exposed for 1 h to 30 mM glucose revealed an intense NF-kB activation. Treatment of HUVEC exposed to high glucose with the NF-kB inhibitors pyrrolidinedithiocarbamate (100 microM) and tosyl-phe-chloromethylketone (25 microM) significantly reduced (P < 0.05) leukocyte adhesion in respect to HUVEC treated with glucose alone. A significant (P < 0.01) inhibitory effect on glucose-induced leukocyte adhesion was observed after blocking protein kinase C activity with staurosporine (5 nM). When HUVEC were treated with specific antisense oligodesoxynucleotides against PKCalpha and PKCepsilon isoforms before the addition of 30 mM glucose, a significant (P < 0.05) reduction in the adhesion was also seen. Advanced glycosylation end product-albumin significantly increased the number of adhering leukocytes in respect to native albumin used as control (110+/-16 versus 66+/-7, P < 0.01). Sera from diabetic patients significantly (P < 0.01) enhanced leukocyte adhesion as compared with controls, despite normal levels of IL-1beta and TNFalpha in these sera. These data indicate that high glucose concentration and hyperglycemia promote leukocyte adhesion to the endothelium through upregulation of cell surface expression of adhesive proteins, possibly depending on NF-kB activation.

To identify transcriptionally regulated genes potentially involved in the effect of shear stress on endothelial gene expression, we performed a differential display analysis of mRNAs from human umbilical vein endothelial cell (HUVEC) exposed to laminar shear stress (12 dynes/cm2) in comparison to HUVEC maintained in static condition. We identified a cDNA fragment overexpressed by laminar shear stress. The full-length, SSK1, was 3653 long and encoded for a novel protein of 1050 amino acids. Northern blot demonstrates that SSK1 mRNA is expressed at high levels also in placenta, a weak transcript was present in heart, skeletal muscle, kidney and pancreas. Homology searches of the protein databases showed that SSK1 is related to numerous serine-threonine kinases. The highest homology was found with a very recently described gene, BUBR1, an analogue of BUB1, which is a kinase involved in the regulation of cell cycle. The most conserved residues in catalytic domains II, III, VIb, VII, VIII and IX of serine-threonine protein kinases were found in the C terminal region of SSK1 which further supports the kinase nature of the new protein. The putative serine-threonine kinase SSK1 may represent a tool by which mechanical forces regulates phosphorylation events within endothelial cells.

We investigated the effect of hemodynamic shear forces on the expression of adhesive molecules, E-selectin, and intercellular adhesion molecule-1 (ICAM-1) on human umbilical vein endothelial cells (HUVEC) exposed to laminar (8 dynes/cm2) or turbulent shear stress (8.6 dynes/cm2 average), or to a static condition. Laminar flow induced a significant time-dependent increase in the surface expression of ICAM-1, as documented by flow cytometry studies. Endothelial cell surface expression of ICAM-1 in supernatants of HUVEC exposed to laminar flow was not modified, excluding the possibility that HUVEC exposed to laminar flow synthetize factors that upregulate ICAM-1. The effect of laminar flow was specific for ICAM-1, while E-selectin expression was not modulated by the flow condition. Turbulent flow did not affect surface expression of either E-selectin or ICAM-1. To evaluate the functional significance of the laminar-flow-induced increase in ICAM-1 expression, we studied the dynamic interaction of total leukocyte suspension with HUVEC exposed to laminar flow (8 dynes/cm2 for 6 hours) in a parallel-plate flow chamber or to static condition. Leukocyte adhesion to HUVEC pre-exposed to flow was significantly enhanced, compared with HUVEC maintained in static condition (233 +/- 67 v 43 +/- 16 leukocytes/mm2, respectively), and comparable with that of interleukin-1 beta treated HUVEC. Mouse monoclonal antibody anti-ICAM-1 completely blocked flow-induced upregulation of leukocyte adhesion. Interleukin-1 beta, which upregulated E-selectin expression, caused leukocyte rolling on HUVEC that was significantly lower on flow- conditioned HUVEC and almost absent on untreated static endothelial cells. Thus, laminar flow directly and selectively upregulates ICAM-1 expression on the surface of endothelial cells and promotes leukocyte adhesion. These data are relevant to the current understanding of basic mechanisms that govern local inflammatory reactions and tissue injury.

The pathophysiology of glomerular lesions of membranous nephropathy (MN), including seldom-reported IgG4-related disease, is still elusive. Unlike in idiopathic MN where IgG4 prevails, in this patient IgG3 was predominant in glomerular deposits in the absence of circulating anti-phospholipase A2 receptor antibodies, suggesting a distinct pathologic process. Here we documented that IgG4 retrieved from the serum of our propositus reacted against carbonic anhydrase II (CAII) at the podocyte surface. In patient's biopsy, glomerular CAII staining increased and co-localized with subepithelial IgG4 deposits along the capillary walls. Patient's IgG4 caused a drop in cell pH followed by mitochondrial dysfunction, excessive ROS production and cytoskeletal reorganization in cultured podocytes. These events promoted mitochondrial superoxide-dismutase-2 (SOD2) externalization on the plasma membrane, becoming recognizable by complement-binding IgG3 anti-SOD2. Among patients with IgG4-related disease only sera of those with IgG4 anti-CAII antibodies caused low intracellular pH and mitochondrial alterations underlying SOD2 externalization. Circulating IgG4 anti-CAII can cause podocyte injury through processes of intracellular acidification, mitochondrial oxidative stress and neoantigen induction in patients with IgG4 related disease. The onset of MN in a subset of patients could be due to IgG4 antibodies recognizing CAII with consequent exposure of mitochondrial neoantigen in the context of multifactorial pathogenesis of disease., Highlights • In a patient with IgG4-related disease, glomerular CAII increases and colocalizes with IgG4 deposits. • IgG4 from patient's serum reacts against CAII expressed by podocytes. • IgG4 causes acidification, mitochondrial dysfunction and ROS-dependent cytoskeletal alterations in cultured podocytes. • IgG4 induces the externalization on the plasma membrane of clustered SOD2, becoming recognizable by complement-binding IgG3.

Mycophenolate mofetil limits renal damage and prolongs life in murine lupus autoimmune disease. Classical immunosuppressants like cyclophosphamide give excellent results in human lupus nephritis. However, they augment malignancies and viral infections. Here we investigated the effect of the new immunosuppressant agent, mycophenolate mofetil (MMF), in New Zealand Black x New Zealand White (NZBxW) F1 hybrid mice, a model of genetically determined immune complex disease that mimics systemic lupus in humans. MMF has a selective antiproliferative effect on T- and B-lymphocytes, inhibits antibody formation and blocks the glyco-sylation of lymphocyte glycoproteins involved in the adhesion of leukocytes to endothelial cells. Two groups of NZBxW mice were used: group 1 (N = 20) given daily MMF (60 mg/kg p.o.) and group 2 (N = 15) given daily vehicle alone. Treatment started at three months of age and lasted until the death of the animals. Results showed that percentage of proteinuric mice was significantly reduced by MMF treatment and serum BUN levels were also lower than vehicle. MMF had a suppressive effect on autoantibody production and protected animals from leukopenia and anemia. Life survival of MMF treated lupus mice was significantly improved in respect to untreated animals. Thus, MMF delayed renal function deterioration and prolonged life survival in murine lupus nephritis. MMF has been already recognized as reasonably well tolerated in renal transplant patients and despite its gastrointestinal toxicity its overall safety profile appears superior to azathioprine. Human studies are needed to establish whether MMF may function as a steroid-sparing drug in lupus nephritis.

In search for new sources of mesenchymal stem cells (MSCs) for renal repair in acute kidney injury (AKI), we investigated the potential of human cord blood (CB)-MSCs to cure mice with AKI. Infusion of CB-MSCs in immunodeficient mice with cisplatin-induced AKI ameliorated both renal function and tubular cell injury, and prolonged survival. Transplanted CB-MSCs localized in peritubular areas, limited capillary alterations and neutrophil infiltration. Apoptosis reduced and tubular cell proliferation increased by virtue of stem cell capacity to produce growth factors. The reno-protective effect of CB-MSCs was further confirmed by their ability to inhibit oxidative damage and to induce the prosurvival factor Akt in tubular cells. The evidence that CB-MSCs in vitro increased the production of growth factors and inhibited IL-1β and TNFα synthesis when cocultured with damaged proximal tubular cells indicates a regenerative and anti-inflammatory action of stem cell treatment. Altogether these results highlight the potential of human CB-MSCs as future cell therapy for testing in human AKI.