Research team

Pathophysiology

Expertise

Renal failure can occur in an acute (hours or days) or a chronic (years) setting. Acute kidney injury (AKI) refers to a rapid decrease in renal function and is mainly caused by exposure to nephrotoxic substances, impaired renal blood flow, renal inflammation and obstruction of the urinary tract. In addition to its immediate detrimental effects on body homeostasis, AKI can predispose the kidney to develop progressive chronic kidney disease (CKD) [1]. CKD is a world-wide recognized public health problem affecting 8–16% of the world population [2] and representing a progressive loss of renal function over a period of months or years, ultimately leading to end stage renal disease (CKD stage 5), which inevitably requires renal replacement therapy, i.e., dialysis or kidney transplantation. CKD causes important distortions of the bodies’ mineral balance. A disrupted calcium-phosphate balance is the reason why CKD patients develop important co-morbidities at the level of the bone and the vessels. A disturbed mineral balance viz. hypocalcemia and hyperphosphatemia results in renal osteodystrophy, a term covering various types of bone lesions characterized by either an increased or decreased bone turnover and reduced bone strength/quality. At the level of the vessels, CKD goes along with the induction of vascular media calcifications. Vascular media calcifications and their cardiovascular consequences are the most important cause of death of CKD patients. Renal osteodystrophy together with vascular media calcification is called CKD mineral bone disorder (CKD-MBD) and can be considered to result from a pathologically disturbed bone-vascular interaction. The concomitant occurrence of a disturbed bone turnover and vascular media calcifications (this phenomenon, also referred to as the calcification paradox) occurs not only in CKD- but also in non-CKD patients (diabetics and osteoporosis patients), extending its clinical relevance. To date, effective treatment directly targeting the kidney to attenuate AKI or halt the progression of CKD is lacking. Current treatment for AKI is mainly supportive with correction of volume overload and biochemical abnormalities as primary goals; treatment strategies for CKD mainly focus on controlling important risk factors such as hypertension but cannot avoid that patients progressively loose kidney function. The same is true for a disturbed bone-vascular axis, of which treatment only exists of controlling its risk factors. Within our team of the mineral homeostasis subunit in the Pathophysiology lab, we essentially perform both fundamental and applied research on the mechanisms, treatment and prevention of (renal-induced) vascular and bone pathology.

Development of a cutting-edge service platform for in vivo preclinical testing of drug candidates able to treat chronic kidney disease and its associated co-morbidities. 01/09/2020 - 31/08/2021

Abstract

Disorders of mineral metabolism, specifically calcium and phosphorus homeostasis, are common in patients with chronic kidney disease (CKD), diabetes and osteoporosis. CKD is a world-wide recognized public health problem affecting 8-16% of the world population. Also the prevalence of diabetes and osteoporosis is high (12.3% for diabetes and 30% for osteoporosis of all postmenopausal women) and still increasing. Essentially, these three disorders of mineral metabolism typically share interconnected features including renal failure, vascular calcification and aberrant bone metabolism. CKD represents a progressive loss of renal function over a period of months or years ultimately leading to end-stage renal disease, which inevitably requires renal replacement therapy, i.e. dialysis and kidney transplantation. Vascular calcification in the medial layer of blood vessels is a major clinical problem and the most important cause of death in CKD patients. Structures similar to bone and cartilage are detected in the calcified arterial wall thereby mimicking bone formation. In addition, the disturbed mineral metabolism in CKD patients leads to the development of renal osteodystrophy which ultimately result in a reduced bone strength and increased incidence of bone fractures. The concomitant occurrence of a disturbed bone metabolism with a pathological calcification of the vessel wall in CDK patients is referred to as "the calcification paradox", which is also observed in diabetes and osteoporosis patients. The strong increase in the number of elderly boosts the prevalence of aging-related disorders such as CKD, diabetes and osteoporosis, and herewith the interest of pharmaceutical companies in clinical as well as preclinical research on these disorders. During the last decade, the Laboratory of Pathophysiology has developed unique animal models for the in vivo investigatation of different aspects of this interconnected triad (kidney, vessels and bone) in mineral metabolism disorders. These animal models besides investigation of fundamental mechanisms underlying these pathophysiological processes also allow to intervene in these processes by candidate therapeutics. This unique combination of animal models, substantiated by fundamental pathological knowledge, resulted in a cutting edge platform for preclinical (animal model) drug testing, which successfully attracted contract research with industrial partners resulting in an income of 500k€/year during the last decade. From our unique position at the interface between academics and industry, we note that industrial interest is shifting from symptomatic treatment (hypertension or hyperphosphatemia) towards a direct interference with CKD and vessel wall calcification. To anticipate this trend and level-up the valorization potential of our current platform of animal models, this IOF-service platforms project aims to expands its portfolio and setup novel innovative animal models to guarantee a further increase in industrial revenue.

Researcher(s)

Research team(s)

In depth investigation of causal pathophysiological mechanisms and underlying molecular signaling pathways of arterial stiffness, a life threatening disease with serious impact on multiple organs. 01/01/2020 - 31/12/2023

Abstract

Arterial stiffening is a hallmark of vascular aging and is associated with a high risk of cardiovascular disease and end-organ failure in kidney and brain (dementia). No effective therapies to combat this life threatening pathology currently exist, which is largely due to the lack of knowledge of the underlying molecular mechanisms. Therefore, this project aims to identify novel druggable targets which opens up new perspectives for discovery and evaluation of inventive therapies for this growing epidemic. Endothelial dysfunction and vascular calcification are two well known pathological processes leading to arterial stiffness. Established mouse models of both will be used to identify the molecular signaling pathways responsible for arterial stiffness by use of quantitative proteomics coupled with bioinformatic analysis. We will also explore the reciprocal relationship between different pathological processes leading to arterial stiffness. As impaired autophagy has been suggested to play a role in vascular aging, this project will also focus on its role in vascular calcification and stiffness. To explore whether autophagy is a candidate target for future intervention studies, complementary in vivo studies will be performed that investigate the effect of both autophagy induction and deficiency on vascular calcification and stiffness. Ultimately, this project aims to prevent or possibly reverse stiffening of large arteries to reduce long-term risk for end-organ damage.

Researcher(s)

Research team(s)

Investigating the role of autophagy in arterial calcification and arterial stiffness. 01/12/2019 - 30/11/2021

Abstract

Cardiovascular calcification significantly contributes to cardiovascular disease, which is the leading cause of mortality and a major cause of morbidity in Europe. Cardiovascular calcification occurs in both rare monogenic (e.g. pseudoxanthoma elasticum) and in common acquired diseases (e.g. atherosclerosis and chronic kidney disease). Importantly, cardiovascular calcification is an active but incompletely understood process regulated by a variety of (epi)genetic and environmental factors, acting both systemically and locally. Despite its major clinical impact, no specific therapeutic strategies targeting cardiovascular calcification are applied in current clinical practice. In 2019, the Physiopharmacology and Pathophysiology research groups of the University of Antwerp were both part of the "eRaDiCal" consortium (H2020-MSCA-ITN call) aimed to investigate risk factors and underlying mechanisms across rare and common ectopic calcification disorders for the development of adequate diagnostic, preventive and therapeutic solutions to target cardiovascular calcification. eRaDiCal received an excellent reviewer score (94.8%, reserve list), but was not funded. As part of its strategic research plan, the University of Antwerp provides funding for excellent H2020 proposals to facilitate and encourage a successful resubmission. The teams of Physiopharmacology and Pathophysiology will use the budget to substantiate the evidence base on the role of autophagy in arterial calcification and stiffness. The intention is to recruit a (part-time) postdoc and/or PhD student to obtain preliminary data during the next year.

Researcher(s)

Research team(s)

In vitro and in vivo research to investigate the role of the Wnt/beta-catenin signaling cascade in vascular calcification and the bone-vascular axis. 01/10/2018 - 30/09/2021

Abstract

The calcification paradox is seen in chronic kidney disease (CKD) and osteoporosis patients and refers to the occurrence of a bone pathology characterized by a disturbed bone turnover/mineralisation in combination with calcification of the medial layer of the vessel wall; i.e. arteriosclerosis. This process of vascular calcification, which shares many similarities to bone development, is a rapidly progressive aspect of cardiovascular disease and is linked to increased morbidity and mortality particularly in CKD patients. As safe therapies to treat these mineralisation defects are urgently needed, this topic raised great interest during the last years. A pathway that might clarify the co-occurrence of mineralisation defects at the level of bone and vasculature is the Wnt/beta-catenin signalling pathway. It is known that this pathway regulates bone formation, however, its role in vascular calcification is less clear. The most obvious strategy in elucidating the potential (patho-)physiological roles of this cascade is by studying the functions of sclerostin and Dickkopf-related protein 1 (DKK1), both well-known inhibitors of the Wnt/beta-catenin signalling. Additionally, concerns are raised against the cardiovascular safety of anti-Scl and anti-DKK1 antibodies which are currently tested in clinical trials as a treatment for osteoporosis. Therefore, clarifying the mechanisms underlying this paradox is essential for the development of safe preventive and therapeutic treatments.

Researcher(s)

Research team(s)

Identification of signaling pathways as druggable targets to combat vascular stiffness, a life threatening vascular pathology with high impact on multiple organs. 01/01/2018 - 31/12/2021

Abstract

Vascular stiffening is a growing epidemic associated with a high risk of cardiovascular disease, and end organ-damage in kidney and brain. No effective therapies to combat this life threatening vascular pathology currently exist, which is largely due to the lack of knowledge on the underlying molecular mechanisms. Therefore, this project aims to identify novel druggable targets which opens up new perspectives for discovery and evaluation of inventive therapies. Endothelial dysfunction and vascular calcification are well known pathological processes leading to vascular stiffness. Established mouse models of endothelial dysfunction and vascular calcification will therefore be used to identify the molecular signaling pathways responsible for vascular stiffness by means of a proteomic approach of arterial tissue. Additionally, we will explore the reciprocal relationship between endothelial dysfunction, vascular calcification and stiffness. As impaired autophagy has been suggested to play a role in vascular aging, this project will also focus on its role in vascular calcification and stiffness. To explore whether autophagy is a candidate target for future intervention studies, complementary in vivo studies will be performed that investigate the effect of both autophagy induction and defective autophagy on vascular calcification and stiffness. Broader ambitions of this project are to reduce the impact and lower the economic burden of vascular stiffness on society.

Researcher(s)

Research team(s)

The use of metformin in the battle against chronic kidney disease and its cardiovascular complications. 01/10/2017 - 30/09/2021

Abstract

Over the past decades metformin is the optimal first-line drug for type 2 diabetes mellitus (T2DM) with 70 million prescriptions in the United States in 2013. Only in the last few years, it has become clear that metformin exerts benign pleiotropic actions beyond its prescribed use and ongoing investigations focus on its anti-ageing and anti-cancer properties. Recent data from preclinical and clinical studies are additionally pointing towards a putative beneficial impact of metformin on the kidney and cardiovascular system. Chronic kidney disease (CKD) is a world-wide recognized public health problem affecting 8–16% of the world population and represents a progressive loss of renal function over a period of months or years ultimately leading to end stage renal disease (CKD stage 5) which inevitably requires renal replacement therapy, i.e. dialysis or kidney transplantation. CKD also confers a markedly increased risk of cardiovascular disease (mainly vascular calcification) which accounts for 50% of all deaths in this population. Current treatment strategies for bot CKD and vascular calcification mainly focus on controlling important risk factors, however to date, effective treatment directly targeting the kidney and/or the vessels is lacking. Therefore the current project aims to investigate the possibility to use metformin in the treatment/prevention of CKD and its most important complication vascular calcification. Hereto the following objectives are put forward: (1) to investigate whether metformin is able to slow down or arrest the progression of CKD in rats with mild to moderate CKD and (2) to investigate whether metformin can prevent calcification in the arteries in an established rat model of vascular calcification. For the whole project, we will study the effect of metformin at the functional, structural (histopathological) and mechanistic level of the kidney and the aorta. Therefore, we will use both conventional and novel, more challenging techniques. If this project manages to demonstrate that this agent is able to retard or effectively halt the progression of CKD and to prevent, slow down or even arrest the development of vascular calcification, one of the major comorbidities of CKD, a major step forward will be taken in the treatment of this expanding population in our ageing society. Undoubtedly, such a finding will have far-reaching clinical and social benefits for the patients as well as a significant financial relieve for health insurance systems, taken into account the low cost of this generic drug (few euros/month) versus the high financial impact of dialysis and transplantation.

Researcher(s)

Research team(s)

Development of effective treatments for vascular media calcification, a major clinical issue in our ageing population. 01/01/2017 - 31/12/2021

Abstract

Vascular calcification or the deposition of calcium-phosphate crystals in the arteries has a severe impact on morbidity/mortality in elderly and patients with chronic kidney disease (CKD) and diabetes mellitus (DM) by inducing severe cardiovascular events. In our ageing society (CKD and DM are ageing diseases), treatment for vascular calcification is warranted. However, current therapies only consist of controlling risk factors and therefore effective therapies to prevent/cure vascular calcification are lacking. For this reason we aim to investigate new treatment strategies that directly inhibit arterial calcification in two ways (i) directly interfering with crystal formation in the vessel wall and (ii) directly targeting the predominant cells in arterial calcification; by targeting respectively cell receptor independent and dependent effects of extracellular nucleotides on the vascular calcification process. Treatments will not only be tested for their ability to prevent vascular calcifications but also to attenuate the progression of pre-existing calcifications as most patients present themselves with a given degree of vascular calcification. Since vascular calcification shares many features with the bone formation process it is furthermore important to test new therapies inhibiting vascular calcifications for negative effects on the bone. In conclusion, the aim of this project is to develop effective therapies for vascular calcification without side-effects on the bone

Researcher(s)

Research team(s)

In vitro and in vivo research to investigate the role of the Wnt/betacatenin signalling cascade in the calcification paradox by targeting its most important inhibitors DKK1 and sclerostin. 01/10/2016 - 30/09/2018

Abstract

The calcification paradox is seen in chronic kidney disease (CKD) and osteoporosis patients and refers to the occurrence of a bone pathology characterized by a disturbed bone turnover/mineralisation in combination with calcification of the medial layer of the vessel wall; i.e. arteriosclerosis. This process of vascular calcification, which shares many similarities to bone development, is a rapidly progressive aspect of cardiovascular disease and is linked to increased morbidity and mortality particularly in CKD patients. As safe therapies to treat these mineralisation defects are urgently needed, this topic raised great interest during the last years. A pathway that might clarify the co-occurrence of mineralisation defects at the level of bone and vasculature is the Wnt/beta-catenin signalling pathway. It is known that this pathway regulates bone formation, however, its role in vascular calcification is less clear. The most obvious strategy in elucidating the potential (patho-)physiological roles of this cascade is by studying the functions of sclerostin and Dickkopf-related protein 1 (DKK1), both well-known inhibitors of the Wnt/beta-catenin signalling. Additionally, concerns are raised against the cardiovascular safety of anti-Scl and anti-DKK1 antibodies which are currently tested in clinical trials as a treatment for osteoporosis. Therefore, clarifying the mechanisms underlying this paradox is essential for the development of safe preventive and therapeutic treatments.

Researcher(s)

Research team(s)

The role of sclerostin in vascular calcification and the calcification paradox: necessary research for development of safe therapies to treat mineralization defects in bone and vessels. 01/10/2015 - 30/09/2016

Abstract

Cardiovascular disease is responsible for a substantial part of mortality in patients with chronic kidney disease (CKD) or diabetes (also a cause of CKD). Vascular calcification (VC) is a rapidly progressive, prominent aspect of cardiovascular disease in these patients as well as in those with osteoporosis. Remarkably, pathological VC in these patient groups goes along with disturbed bone metabolism. This association is called the calcification paradox. Development of new, safe therapies to treat the mineralization defects in bone and vessels is urgently needed. Sclerostin (Scl) is a protein produced by bone cells (osteocytes), inhibiting bone formation and mineralization. VC is regulated similarly to that of developing bone: vascular smooth muscle cells (VSMC) transdifferentiate to cells with a bone-like phenotype and proteins involved in bone formation also regulate the development of VC. Scl expression has been found in VSMC during calcification and CKD patients with VC were observed to have higher serum Scl. The Laboratory of Pathophysiology was the first to find an association between increased serum Scl and decreased mortality in hemodialysis patients. Hence, it is not surprising that during the last years the potential role of Scl in vascular pathophysiology and the calcification paradox has received increasing interest. This project aims to elucidate the complex role of Scl in mineralistation defects of bone and vessels and their reciprocal effects onto each other -

Researcher(s)

Research team(s)

The role of sclerostin in vascular calcification and the calcification paradox: necassary research for development of safe therapies to treat mineralization defects in bone and vessels. 01/01/2015 - 31/12/2018

Abstract

The current project aims to elucidate the role of sclerostin in vascular calcification and its complex relationship with disturbed physiological bone mineralization, in particular in patients with chronic kidney disease. This research is necassary in order to develop safe therapies for these pathologies.

Researcher(s)

Research team(s)

Cell cycle control in proximal epithelial cells during progression of acute kidney injury to chronic kidney disease in vivo. 01/01/2013 - 31/12/2016

Abstract

The proposed project aims at getting profound molecular insight in cell cycle control of the proximal tubular epithelial cell in injured kidneys, an event recently recognized to play a critical role in the progression of acute kidney injury to chronic kidney disease.

Researcher(s)

Research team(s)

Investigation of intestinal oxalate binding as a new therapy for the prevention of nephrolithiasis/nephrocalcinosis. 01/10/2011 - 30/09/2015

Abstract

In the present project we will evaluate the usefulness of lanthanum carbonate in the prevention of hyperoxaluria/renal calcifications by investigating its capability to limit intestinal oxalate absorption and/or promote oxalate secretion.

Researcher(s)

Research team(s)

Experimental research on the reversibility and prevention of nephrocalcinosis and nephrolithiasis. 01/01/2009 - 31/12/2012

Abstract

Goals of the project: 1. To investigate the bio-physicochemical mechanism of crystal clearance and the role of pH and inflammation therein. 2. To study the fundamental effects of acute hyperphosphatemia induced by therapeutic oral sodium phosphateintake on (i) the systemic regulators of the phosphate balance, (ii) the tubular epithelial phenotype and (iii) renal function, and investigate if these effects can be eliminated by limiting or inhibiting phosphate absorption in the intestine.

Researcher(s)

Research team(s)

Investigation of renal and intestinal oxalate handling: new targets for preventive therapies in the field of renal calcifications. 01/10/2007 - 30/09/2011

Abstract

Aim: Investigate renal and intestinal oxalate handling as new targets for preventive therapies in the field of renal calcifications. Objectives: 1. Investigate the transepithelial transport of oxalate in human renal cells. 2. Investigate the effects of intestinal oxalate binding on oxalate excretion and incidence of renal calcifications.

Researcher(s)

Research team(s)

Cell biological and experimental study of the mechanisms and modulators underlying the protective effect of erythropoietin. 01/07/2007 - 31/12/2011

Abstract

Erythropoietin (EPO) has recently been shown to protect the kidney both functionally and morphologically against acute renal failure induced by ischemia/reperfusion injury, as seen for example after kidney transplantation. The mechanisms underlying this renoprotective effect are not known. This project aims to elucidate the mechanisms of the EPO-induced renoprotection both in vivo (ischemic rat model) and in vitro (human renal tubular cells culture), this in order to justify further clinical studies.

Researcher(s)

Research team(s)

In vitro study into the renal transport of possible nephrotoxic molecules by means of primary human kidney cell cultures. 01/03/2006 - 31/12/2007

Abstract

This project deals with the study of primary, tubular human kidney cell cultures as a possible in vitro model of renal molecule transport. At first instance we are interested in the transport of molecules that are possibly nephrotoxic (for example drugs which are in most cases orgnanic anions or kations) because of their transport by the kidney.

Researcher(s)

Research team(s)

Causes and prevention of distal tubular crystal retention, an essential phase in the development of nephrocalcinosis and -lithiasis. 01/01/2006 - 31/12/2009

Abstract

In order to get a better insight in causes and prevention of nephrocalcinosis and -lithiasis, this project aims to answer the following questions: -is a non-differentiated distal tubular phenotype that is associated with damage/regeneration, the causal factor of crystal retention? -what is the role of osteopontin (OPN), CD44 and hyaluronic acid (HA) in the process of crystal retention? -can crystal retention be prevented by anti-inflammatory therapies?

Researcher(s)

Research team(s)

Expression, metabolism and function of renal osteopontin during renal injury and repair: an approach by cell culture. 01/10/2000 - 30/09/2002

Abstract

Osteopontin (OPN) is a protein present in different tissues and organs including the kidney. In the kidney, the constitutive expression of this glycosylated phosphoprotein is confined to the apical cell surface in the lis of Henle and more distal parts of the nephron. After acute renal damage OPN is also present in perinuclear vesicles in proximal tubular cells. OPN function is unknown, but a role in tissue remodelling is suggested both by its molecular structure and upregulated expression during increased cell turnover in a variety of tissues. However, knowledge concerning its expression, metabolism and activity is insufficient to define the function of OPN in a precise and well-founded manner. Its renal biology has never been studied in cultures of human kidney cells. The general aim of this project is to gain a better insight in the function of renal OPN. Primary kidney cell cultures will allow the study of the heterogenic nephron cell population in both a mixed and separated manner. First, expression and metabolism of OPN will be studied, either or not after induction of cell damage, which can be considered as an in vitro analogue of acute renal failure. Next, blocking of OPN expression during further experiments may reveal some of its activities related to tissue remodelling. In a first part of this project primary kidney cell cultures will be established. Human mixed and separated (for example distal versus proximal) cultures have already been developed in our laboratory. Immunocytochemical identification and separation of cells is based on specific cell surface markers. Mixed cultures of rat and mice kidney cells will also be developed in view of the availability of OPN knockout mice and to allow the comparison with in vivo rat models of acute renal failure, respectively. The second part of this study will entail the development of detection methods for OPN expression and phosphorylation in cell culture. Both the mRNA level (Northern blotting, in situ hybridisation) and the protein level (immunocytochemistry, immunoblotting and ELISA) will be studied. During part three of this project OPN binding and possible internalisation by tubular cells will be studied by the addition of labeled OPN, either or not phosphorylated, to primary kidney cell cultures. In a fourth part it will be investigated whether induction of cell damage by hypoxia, lipopolysaccharide or HgCl2 results in a different expression and metabolization pattern of OPN. A number of parameters in relation to tissue remodelling will be examined (before and after cell damage) in kidney cell cultures from OPN knockout versus wild-type mice during the fifth part of this study. Parameters that will be examined are viability, growth, adhesion, differentiation, vimentin expression and inhibition of NO synthase (iNOS). Observed differences may be abrogated by adding recombinant or native bovine OPN to the cultures. In order to confirm the observations in knockout mice, OPN function will be studied during the sixth and last part of this study by the addition of oligodeoxynucleotides to the cell cultures before and after induction of cell damage. A dose-dependent effect may be observed. Moreover it will enable to perform measurements in the same system before and after blocking of OPN synthesis. The results of this research project may contribute to the development of diagnostic applications and the implementation of new therapeutic approaches of acute renal failure.

Researcher(s)

Research team(s)

    Expression, metabolism and function of renal osteopontin during renal injury and repair: an approach by cell culture. 01/10/1998 - 30/09/2000

    Abstract

    Osteopontin (OPN) is a protein present in different tissues and organs including the kidney. In the kidney, the constitutive expression of this glycosylated phosphoprotein is confined to the apical cell surface in the lis of Henle and more distal parts of the nephron. After acute renal damage OPN is also present in perinuclear vesicles in proximal tubular cells. OPN function is unknown, but a role in tissue remodelling is suggested both by its molecular structure and upregulated expression during increased cell turnover in a variety of tissues. However, knowledge concerning its expression, metabolism and activity is insufficient to define the function of OPN in a precise and well-founded manner. Its renal biology has never been studied in cultures of human kidney cells. The general aim of this project is to gain a better insight in the function of renal OPN. Primary kidney cell cultures will allow the study of the heterogenic nephron cell population in both a mixed and separated manner. First, expression and metabolism of OPN will be studied, either or not after induction of cell damage, which can be considered as an in vitro analogue of acute renal failure. Next, blocking of OPN expression during further experiments may reveal some of its activities related to tissue remodelling. In a first part of this project primary kidney cell cultures will be established. Human mixed and separated (for example distal versus proximal) cultures have already been developed in our laboratory. Immunocytochemical identification and separation of cells is based on specific cell surface markers. Mixed cultures of rat and mice kidney cells will also be developed in view of the availability of OPN knockout mice and to allow the comparison with in vivo rat models of acute renal failure, respectively. The second part of this study will entail the development of detection methods for OPN expression and phosphorylation in cell culture. Both the mRNA level (Northern blotting, in situ hybridisation) and the protein level (immunocytochemistry, immunoblotting and ELISA) will be studied. During part three of this project OPN binding and possible internalisation by tubular cells will be studied by the addition of labeled OPN, either or not phosphorylated, to primary kidney cell cultures. In a fourth part it will be investigated whether induction of cell damage by hypoxia, lipopolysaccharide or HgCl2 results in a different expression and metabolization pattern of OPN. A number of parameters in relation to tissue remodelling will be examined (before and after cell damage) in kidney cell cultures from OPN knockout versus wild-type mice during the fifth part of this study. Parameters that will be examined are viability, growth, adhesion, differentiation, vimentin expression and inhibition of NO synthase (iNOS). Observed differences may be abrogated by adding recombinant or native bovine OPN to the cultures. In order to confirm the observations in knockout mice, OPN function will be studied during the sixth and last part of this study by the addition of oligodeoxynucleotides to the cell cultures before and after induction of cell damage. A dose-dependent effect may be observed. Moreover it will enable to perform measurements in the same system before and after blocking of OPN synthesis. The results of this research project may contribute to the development of diagnostic applications and the implementation of new therapeutic approaches of acute renal failure.

    Researcher(s)

    Research team(s)