A relaxin hatása a progressziv vesefibrózisra Alb/relaxin transzgenikus egerekben = The effect of relaxin on progressive renal fibrosis in Alb/relaxin transgenic mice

FVB/N alb/relaxin transzgenikus egereket hoztunk létre, hogy megvizsgáljuk az emelkedett plazma relaxin szint hatását vesefibrózis progressziójára. Ezek a transzgenikus egerek kizárólag a májukban expresszálják a relaxin transzgént. 12 hónapos korukra glomeruláris fibrozist és intersticiális infiltrációt figyeltünk meg. A transzgenikus egerek veséjében fokozott fibronektin festést találtunk. Ahhoz, hogy relaxin és TGF-beta kettős transzgenikus hibrid egerekben vizsgáljuk a vesefibrózis progresszióját először vissza kellett keresztezni 15 generáción kersztül az inhomogén genetikai hátterű TGF-beta egereket a beltenyészett C57Bl6 háttérre. A homogén genetikai háttéren eltűnt az a kettős fenotipus, mely jellemzte a TGF-beta transzgenikus egereket. Az állatoknak azonos keringő TGF-beta plazma szintje volt, de a C57Bl6 háttéren csak a fibrózis enyhe formája alakult ki, bizonyítva ezzel a genetikai háttér fontosságát vesefibrózisban. | We have generated FVB/N alb/relaxin transgenic mice to investigate the effect of elevated plasma relaxin level on progression of renal fibrosis. These mice express the transgene exclusively in the liver. At 12 month of age they are characterized with mild glomerular fibrosis and intersticial infiltration. Also increased fibronectin is present in the kidney of transgenic mice. We wished to cross these mice to generate hybrid animals with the alb/TGF-beta1 transgenic mice which are characterized with progressive renal fibrosis. First we have backcrossed the alb/TGF-beta1 transgene to the C57Bl6 inbred strain for 13 generations and compared to C57Bl/6 x CBA F2 mice. As we expected the dual phenotype disappeared on the homogeneous background. The C57Bl6 alb/TGF-beta1 transgenic mice had similarly elevated plasma concentrations of TGF-beta1 than C57Bl/6 x CBA F2 mice, but they developed renal fibrosis of a moderate degree which emphasize the importance of genetic background on renal fibrosis

Magnesium-dependent atpase as a possibility for the investigation of deponating environmental loads in a hepatocyte model

Chemicals that load the environment can be chlorobenzenes with massive chemical stability. They induce a dose-dependent toxic effect in the cells of affected tissues, and because of their high frequency of occurrence in the food chain, they can be used as expositors in environmental exposure models. In this work, we wanted to investigate the magnesium-dependent ATPase activity of chlorobenzenes in hepatocytes

Sugar substitute compounds as environmental exposures - aspects from neuroendocrine functions

It is an extremely interesting question to what extent elements of psychic activity (e.g. cognition) in social existence can change by mediating neuroendocrine communication when it is necessarily altered by chemical environmental influences (e.g. nutritional biological agents) through real technosphere exposures. In the processes of learning and memory, biological mechanisms regulated by the neuro-endocrine system appear predominantly, showing a network relationship with essential local system properties. Exposures (dietary supplements) are tested on in vitro models by monitoring the events of neuro-endocrinological communication (hormone secretions, monoamine /adrenaline and serotonine/) and their changes in exposure

Vese ischemia/reperfúziós károsodásának gátlása RNS interferencia segítségével = RNA interference (RNAi) to limit kidney ischemia/reperfusion injury.

Az RNS interferencia a génterápia új, ígéretes területe. Korábbi kísérleteink során elsőként alkalmaztuk ezt az új technológiát a vese ischemia-reperfúzós károsodásának gátlására (Hamar: PNAS, 2004, US.Apps - 20080227733). Az intenzív osztályon bekövetkezett haláleset kb. 30%-a a vese oxigénhiányos károsodásának következménye. Az oxigénhiányos állapotban elszenvedett szövetkárosodást kiterjedésében, súlyosságában meghaladhatja a véráramlás újbóli megindulását követő reperfúziós károsodás. A reperfúziós során keletkező oxigén szabadgyökök következtében súlyos oxidatív stressz okoz károsodást, és a sejtek programozott sejthalál (apoptózis) útján pusztulnak el. Ezért kísérleteink célja a vese reperfúziós károsodásának csökkentése. A FAS apoptózis receptor termelődését gátoló kezelésünk javította a veseműködést és a túlélést. A szabadgyök-termelő enzim kaszkád első elemét a NADPH-oxidáz (NOX-2,4) enzim termelődését gátló siRNS sejtkultúrában és egér-modellen javította a túlélést, a vese-működést. Kísérleteink során továbbá vizsgáljuk, az siRNS bejuttatásának leghatékonyabb módját, és az esetleges mellékhatásokat is. Eredményeinket két közleményben foglaltuk össze. A célszervbe-sejtbe történő bejuttatás hatékonyságának növelésében, sejt-specifikus célzott bevitel kifejlesztésében segítségünkre van Judy Liebermannal (Harvard Medical School, Boston, USA) akivel együttműködésben fejlesztettük ki az RNS interferencia alkalmazását egér máj és vese betegségek kezelésére. | RNA interference is a new, promising field of gene-therapy. We were the first, to apply this technique to inhibit reperfusion injury of the kidney (Hamar: PNAS, 2004, US.Apps - 20080227733). Renal oxygen depletion is a leading cause of death at the Intensive Care Units (ICU). Reperfusion injury following reconstitution of blood supply may substantially exceed the damage due to oxygen deficiency (ischemic injury). Oxygen radicals, produced during reperfusion induce a severe oxidative stress, and cells are lost through programmed cell death (apoptosis). Thus, our aim is to reduce reperfusion injury of the kidney. Inhibition of FAS apoptosis receptor improved renal function and survival. Inhibition of NADPH-oxidase (NOX-2,4) - the first enzyme of the oxidative radical producing enzyme cascade improved renal function, and cell survival in cell culture and mouse model. We summarized our data in 2 publications. Furthermore, we investigate the most effective way of targeting the siRNA in the right cell, and possible side-effects of siRNA in collaboration with Judy Liebermann (Harvard Medical School, Boston, USA), with whom we have developed application of RNA interference in mice for renal and liver diseases

PPARγ is a gatekeeper for extracellular matrix and vascular cell homeostasis: beneficial role in pulmonary hypertension and renal/cardiac/pulmonary fibrosis.

PURPOSE OF REVIEW: Pulmonary arterial hypertension (PAH) is characterized by pulmonary arterial endothelial cell (PAEC) dysfunction and apoptosis, pulmonary arterial smooth muscle cell (PASMC) proliferation, inflammation, vasoconstriction, and metabolic disturbances that include disrupted bone morphogenetic protein receptor (BMPR2)-peroxisome proliferator-activated receptor gamma (PPARγ) axis and DNA damage. Activation of PPARγ improves many of these mechanisms, although erroneous reports on potential adverse effects of thiazolidinedione (TZD)-class PPARγ agonists reduced their clinical use in the past decade. Here, we review recent findings in heart, lung, and kidney research related to the pathobiology of vascular remodeling and tissue fibrosis, and also potential therapeutic effects of the PPARγ agonist pioglitazone. RECENT FINDINGS: Independent of its metabolic effects (improved insulin sensitivity and fatty acid handling), PPARγ activation rescues BMPR2 dysfunction, inhibits TGFβ/Smad3/CTGF and TGFβ/pSTAT3/pFoxO1 pathways, and induces the PPARγ/apoE axis, inhibiting vascular remodeling. PPARγ activation dampens mtDNA damage via PPARγ/UBR5/ATM pathway, improves function of endothelial progenitor cells (EPCs), and decrease renal fibrosis by repressing TGFβ/pSTAT3 and TGFβ/EGR1. SUMMARY: Pharmacological PPARγ activation improves many hallmarks of PAH, including dysfunction of BMPR2-PPARγ axis, PAEC, PASMC, EPC, mitochondria/metabolism, and inflammation. Recent randomized controlled trials, including IRIS (Insulin Resistance Intervention After Stroke Trial), emphasize the beneficial effects of PPARγ agonists in PAH patients, leading to recent revival for clinical use

A fibrocyte model for monitoring environmental chemicals

Human activity affects all elements of the Earth's environment and the system of relationships between them. Chlorobenzenes created during chemicalization are capable of modulating the adaptation potential of biological organisms and because of their high frequency of occurrence in the food chain, they can be used as expositors in environmental exposure models. It is necessary to develop a biological model system suitable for the investigation of environmental pollutant chemical agents, which indicates changes quickly and easily

Ductular reaction correlates with fibrogenesis but does not contribute to liver regeneration in experimental fibrosis models

BACKGROUND AND AIMS: Ductular reaction is a standard component of fibrotic liver tissue but its function is largely unknown. It is supposed to interact with the matrix producing myofibroblasts and compensate the declining regenerative capacity of hepatocytes. The relationship between the extent of fibrosis-ductular reaction, proliferative activity of hepatocytes and ductular reaction were studied sequentially in experimental hepatic fibrosis models. METHODS: Liver fibrosis/cirrhosis was induced in wild type and TGFbeta overproducing transgenic mice by carbon tetrachloride and thioacetamide administration. The effect of thioacetamide was modulated by treatment with imatinib and erlotinib. The extent of ductular reaction and fibrosis was measured by morphometry following cytokeratin 19 immunofluorescent labeling and Picro Sirius staining respectively. The proliferative activity of hepatocytes and ductular reaction was evaluated by BrdU incorporation. The temporal distribution of the parameters was followed and compared within and between different experimental groups. RESULTS: There was a strong significant correlation between the extent of fibrosis and ductular reaction in each experimental group. Although imatinib and erlotinib temporarily decreased fibrosis this effect later disappeared. We could not observe negative correlation between the proliferation of hepatocytes and ductular reaction in any of the investigated models. CONCLUSIONS: The stringent connection between ductular reaction and fibrosis, which cannot be influenced by any of our treatment regimens, suggests that there is a close mutual interaction between them instead of a unidirectional causal relationship. Our results confirm a close connection between DR and fibrogenesis. However, since the two parameters changed together we could not establish a causal relationship and were unable to reveal which was the primary event. The lack of inverse correlation between the proliferation of hepatocytes and ductular reaction questions that ductular reaction can compensate for the failing regenerative activity of hepatocytes. No evidences support the persistent antifibrotic property of imatinib or erlotinib

A juxtaglomeruláris apparátus parakrin szabélyozása: Funkcionális és morfológiai összefüggések normál és kóros körülmények között = Paracrine Control of the Juxtaglomerular Apparatus: Functional and Morphological Correlations in Health and Disease

Speciális technika kifejlesztésével és a két foton lézermikroszkóp segítségével elsőként tettük láthatóvá in vivo a patkány vese afferens arteriola disztális szakaszán található endotheliális fenesztrációt. Kimértük a fenesztrált terület nagyságát és bizonyítottuk annak életkortól, illetve a szervezet aktuális állapotától függő változását. Real time formában nyomon követtük a renin granulumok ezen keresztüli keringésbe jutását. Igazoltuk, hogy a filtráció már a glomerulust megelőző disztális afferens arteriola szakaszban megkezdődik. Vizualizáltuk a juxtaglomeruláris apparátus intersticiális folyadék mozgását és kimutattuk, hogy a juxtaglomeruláris apparátusba folyadék filtrálódik az afferens arteriolából, a mesangiumon keresztül a glomerulusból, illetve a glomerulusból a macula densan keresztül a disztális tubulusba. Ezek az eredmények alapvetően megkérdőjelezik a juxtaglomeruláris apparátus működésére és jelentőségére vonatkozó eddigi elképzeléseinket. A fenesztráció kialakulását, illetve a hozzátartozó nanocsatornák morfológiáját atomerőmikroszkópiával analizáltuk sejttenyészetben. Az angiotenzin II és a vaszkuláris endotheliális növekedési faktor (VEGF) fokozta a fenesztrumok képződését az AT1, illetve a VEGFR-2 receptoron keresztül. E folyamat függ a p38 aktiválódásától. A fenesztráció fokozódása együtt járt a 40kD-os dextran áteresztőképesség növekedésével és a sejtréteg elektromos impedancia csökkenésével. | With a special technical development and the use of two photon laser microscopy, for the first time, in vivo, we managed to visualize the endothelial fenestration at the distal section of the afferent arteriole in rat kidney. The area of the fenestrated section was measured and its change depending on age and actual condition was demonstrated. The passage of the renin granules into the circulation via these fenestrations were followed in real time. We documented that filtration already starts at the distal part of the afferent arteriole before glomerulus. The interstitial fluid movement in the juxtaglomerular apparatus was visualized. It was also shown that in JGA, fluid is filtered via afferent arteriole, mesangium, glomerulus and macula densa into the distal tubule. These findings basically question our understanding about the function and importance of JGA. The development of fenestration and the morphology of the related nanochannels were analyzed in the cell culture with the help of AFM. Angiotensin II and Vascular Endothelial Growth Factor (VEGF) increased fenestrates via AT1 and VEGFR-2 receptors. This process is p38 dependent. Increase in fenestration was accompanied by increase in permeability to 40kD dextran and decrease in cell layer electrical impedance