Alessandro Domenico Quercia

Rationale of Mesenchymal Stem Cell Therapy in Kidney Injury

Numerous preclinical and clinical studies suggest that mesenchymal stem cells, also known as multipotent mesenchymal stromal cells (MSCs), may improve pathologic conditions involving different organs. These beneficial effects initially were ascribed to the differentiation of MSCs into organ parenchymal cells. However, at least in the kidney, this is a very rare event and the kidney-protective effects of MSCs have been attributed mainly to paracrine mechanisms. MSCs release a number of trophic, anti-inflammatory, and immune-modulatory factors that may limit kidney injury and favor recovery. In this article, we provide an overview of the biologic activities of MSCs that may be relevant for the treatment of kidney injury in the context of a case vignette concerning a patient at high immunologic risk who underwent a second kidney transplantation followed by the development of ischemia-reperfusion injury and acute allograft rejection. We discuss the possible beneficial effect of MSC treatment in the light of preclinical and clinical data supporting the regenerative and immunomodulatory potential of MSCs.

Interaction between systemic inflammation and renal tubular epithelial cells

Systemic inflammation is known to target tubular epithelial cells (TECs), leading to acute kidney injury. Tubular cells have been implicated in the response to inflammatory mediators in ischaemic and septic renal damage. Moreover, loss of tubular cells by apoptosis or epithelial-to-mesenchymal transition may ingenerate conditions that lead to progression towards chronic kidney disease. On the other hand, TECs may actively contribute to the production of inflammatory mediators that may propagate the injury locally or in distant organs. In the present review, we discuss the tubular cell response and its contribution to systemic inflammation.

Endothelial progenitor cell-derived extracellular vesicles protect from complement-mediated mesangial injury in experimental anti-Thy1.1 glomerulonephritis

BACKGROUND Endothelial progenitor cells (EPCs) are known to induce tissue repair by paracrine mechanisms including the release of growth factors and extracellular vesicles (EVs), nanoparticles able to carry proteins and genetic information to target cells. The aim of this study was to evaluate whether EVs derived from EPCs may protect from complement-mediated mesangial injury in experimental anti-Thy1.1 glomerulonephritis. METHODS EVs were isolated by serial ultracentrifugation from supernatants of cultured human EPCs and characterized for their protein and RNA content. In vivo, EVs were injected i.v. in the experimental rat model of mesangiolytic anti-Thy1.1 glomerulonephritis evaluating renal function, proteinuria, complement activity and histological lesions. In vitro, the biological effects of EPC-derived EVs were studied in cultured rat mesangial cells incubated with anti-Thy1.1 antibody and rat or human serum as complement source. RESULTS After i.v. injection in Thy1.1-treated rats, EVs localized within injured glomeruli and inhibited mesangial cell activation, leucocyte infiltration and apoptosis, decreased proteinuria, increased serum complement haemolytic activity (CH50) and ameliorated renal function. EV treatment decreased intraglomerular deposition of the membrane attack complex (MAC or C5b-9) and expression of smooth muscle cell actin and preserved the endothelial antigen RECA-1 and the podocyte marker synaptopodin. The protective effect of EVs was significantly reduced by pre-treatment with a high dose of RNase (1 U/mL), suggesting a key role for EV-carried RNAs in these mechanisms. Indeed, EPC-derived EVs contained different mRNAs coding for several anti-apoptotic molecules and for the complement inhibitors Factor H, CD55 and CD59 and the related proteins. The in vitro experiments aimed to investigate the mechanisms of EV protection indicated that EVs transferred to mesangial cell mRNAs coding for Factor H, CD55 and CD59 and inhibited anti-Thy1.1 antibody/complement-induced apoptosis and C5b-9/C3 mesangial cell deposition. CONCLUSIONS EVs derived from EPCs exert a protective effect in Thy1.1 glomerulonephritis by inhibition of antibody- and complement-mediated injury of mesangial cells.

Caffeic acid, a phenol found in white wine, modulates endothelial nitric oxide production and protects from oxidative stress-associated endothelial cell injury.

Introduction Several studies demonstrated that endothelium dependent vasodilatation is impaired in cardiovascular and chronic kidney diseases because of oxidant stress-induced nitric oxide availability reduction. The Mediterranean diet, which is characterized by food containing phenols, was correlated with a reduced incidence of cardiovascular diseases and delayed progression toward end stage chronic renal failure. Previous studies demonstrated that both red and white wine exert cardioprotective effects. In particular, wine contains Caffeic acid (CAF), an active component with known antioxidant activities. Aim of the study The aim of the present study was to investigate the protective effect of low doses of CAF on oxidative stress-induced endothelial injury. Results CAF increased basal as well as acetylcholine—induced NO release by a mechanism independent from eNOS expression and phosphorylation. In addition, low doses of CAF (100 nM and 1 μM) increased proliferation and angiogenesis and inhibited leukocyte adhesion and endothelial cell apoptosis induced by hypoxia or by the uremic toxins ADMA, p-cresyl sulfate and indoxyl sulfate. The biological effects exerted by CAF on endothelial cells may be at least in part ascribed to modulation of NO release and by decreased ROS production. In an experimental model of kidney ischemia-reperfusion injury in mice, CAF significantly decreased tubular cell apoptosis, intraluminal cast deposition and leukocyte infiltration. Conclusion The results of the present study suggest that CAF, at very low dosages similar to those observed after moderate white wine consumption, may exert a protective effect on endothelial cell function by modulating NO release independently from eNOS expression and phosphorylation. CAF-induced NO modulation may limit cardiovascular and kidney disease progression associated with oxidative stress-mediated endothelial injury.

Detrimental role of humoral signalling in cardio-renal cross-talk

In critically ill patients, any acute organ injury is associated with a sudden change of circulating factors that may play a role in distant organ dysfunction through a complex cross-talk. In this issue, Virzì and colleagues discuss the relevance of humoral signalling between heart and kidney, focusing on type 1 and type 3 cardio-renal syndrome. We herein review the mechanisms of heart-kidney cross-talk, discussing the role of circulating detrimental mediators in the pathogenetic mechanisms of cardio-renal syndrome.

Perfluorocarbon solutions limit tubular epithelial cell injury and promote CD133+ kidney progenitor differentiation: potential use in renal assist devices for sepsis-associated acute kidney injury and multiple organ failure

Background The renal assist device (RAD) is a blood purification system containing viable renal tubular epithelial cells (TECs) that has been proposed for the treatment of acute kidney injury (AKI) and multiple organ failure. Perfluorocarbons (PFCs) are oxygen carriers used for organ preservation in transplantation. The aim of this study was to investigate the effect of PFCs on hypoxia- and sepsis-induced TEC injury and on renal CD133+ progenitor differentiation in a microenvironment similar to the RAD. Methods TECs were seeded in a polysulphone hollow fibre under hypoxia or cultured with plasma from 10 patients with sepsis-associated AKI in the presence or absence of PFCs and were tested for cytotoxicity (XTT assay), apoptosis (terminal deoxynucleotidyl transferase dUTP nick end labeling assay, caspases, enzyme-linked immunosorbent assay, Fas/Fas Ligand pathway activation), mitochondrial activity, cell polarity [transepithelial electrical resistance (TEER)] and adenosine triphosphate production. The effect of PFCs on proliferation and differentiation of human CD133+ progenitors was also studied. Results In the presence of PFCs, TECs seeded into the polysulphone hollow fibre showed increased viability and expression of insulin-like growth factor 1, hepatocyte growth factor and macrophage-stimulating protein. Plasma from septic patients induced TEC apoptosis, disruption of oxidative metabolism, alteration of cell polarity and albumin uptake, down-regulation of the tight junction protein ZO-1 and the endocytic receptor megalin on the TEC surface. These detrimental effects were significantly reduced by PFCs. Moreover, PFCs induced CD133+ renal progenitor cell proliferation and differentiation towards an epithelial/tubular-like phenotype. Conclusions PFCs improved the viability and metabolic function of TECs seeded within a polysulphone hollow fibre and subjected to plasma from septic AKI patients. Additionally, PFCs promoted differentiation towards a tubular/epithelial phenotype of CD133+ renal progenitor cells.

Perfluorocarbon (PFC) Protects Kidney Tubular Epithelial Cells (TEC) by Septic Plasma-Induced Apoptosis And Promotes CD133+ Stem Cell Differentiation: Relevance for Bioartifical Renal Assist Devices (RAD).

LIAL CELLS (TEC) BY SEPTIC PLASMA-INDUCED APOPTOSIS AND PROMOTES CD133 STEM CELL DIFFERENTIATION: RELEVANCE FOR BIOARTIFICAL RENAL ASSIST DEVICES (RAD) Vincenzo Cantaluppi, Federico Figliolini, Davide Medica, Sergio Dellepiane, Sylvia Giacalone, Alessandro D Quercia, Giuseppe P Segoloni, Giovanni Camussi. Nephrology, Dialysis and Renal Transplantation Unit, Department of Internal Medicine, University of Turin, San Giovanni Battista “Molinette” Hospital, Turin, Turin, Italy. Purpose of Study: Extracorporeal blood purification techniques including RAD have been proposed for sepsis-associated acute kidney injury (AKI). The aim of this study was to evaluate the effect of oxygen carrier PFC on septic plasma-induced TEC injury and on renal stem cell differentiation. Methods: Plasma was drawn by 10 patients with sepsis/ AKI (RIFLE). TEC were incubated with plasma in presence/absence of PFC evaluating: apoptosis (TUNEL, caspases), trans-epithelial electrical resistance (TER) and albumin uptake. We studied proliferation (BrdU) and differentiation of CD133 stem cells. Results: Septic plasma induced: 1) a cytotoxic effect on TEC through the activation of the death receptor/mitochondrial apoptotic pathways, 2) an alteration of cell polarity (TER) and albumin uptake; 3) down-regulation of the tight junction protein ZO-1 and of the endocytic receptor megalin. These detrimental effects were significantly reduced in presence of PFC. PFC induced CD133 progenitor proliferation and differentiation toward an epithelial phenotype (increase of TER and expression of markers of fully differentiated TEC). Summary: PFC protects TEC from septic plasmainduced injury and promotes CD133 stem cell differentiation. PFC may improve the results of RAD therapy in sepsis-associated AKI and find a potential application in AKI treatment.