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Az aritmogén cardiomyopathia (ACM) diagnózisa leggyakrabban fizikai terheléssel összefüggő palpitáció vagy syncope, hirtelen szívhalál, illetve jobb kamrai eredetű ritmuszavarok esetén merül fel. A jobb kamrai dominanciájú ACM diagnózisa a 2010-ben módosított Task Force kritériumokon alapul, ami azonban a mindkét kamrát érintő, illetve bal kamrai dominanciájú ACM esetén sokszor nem segíti a diagnózist. Ezekben az esetekben kiemelt szerepe van a kontrasztanyag adásával végzett szív-mágnesesrezonancia- (MR) vizsgálatnak, továbbá a genetikai vizsgálatnak. Két beteg esetét ismertetjük, amikor a klinikai tünetek, vagy a Task Force kritériumok nem voltak ACM-re típusosak. Az 58 éves nőbeteg kivizsgálása szívelégtelenség miatt kezdődött. Szívultrahang-vizsgálat során tág jobb kamra, csökkent jobbkamra-funkció, jelentős tricuspidalis regurgitáció és enyhén emelkedett pulmonalis nyomás igazolódott. Szív-MR-vizsgálattal emelkedett jobb kamrai volumenek, jelentősen csökkent jobb kamrai ejekciós frakció, mindkét kamrát érintő falmozgászavarok és kiterjedt noniszkémiás kontraszthalmozás ábrázolódott, amely alapján felmerült kardiális sarcoidosis, illetve kétkamrás ACM diagnózisa. FDG PET-CT-vizsgálat sarcoidosisra típusos miokardiális dúsulást nem igazolt. Genetikai vizsgálat a Desmoglein 2 gén patogén mutációját igazolta, így kétkamrás érintettségű ACM diagnózisát állítottuk fel. Az 56 éves férfi beteget nyugalomban bekövetkezett eszméletvesztés miatt vizsgáltuk. Koronarográfia ép koszorúsereket igazolt. Telemetriás monitorozással nem tartós kamrai tachycardiát észleltek, elektrofiziológiai vizsgálat során kamrai tachycardiát lehetett kiváltani. Szív-MR-vizsgálat enyhén csökkent bal kamrai ejekciós frakciót, enyhén emelkedett bal kamrai volumeneket igazolt normál jobb kamrai paraméterek mellett. A septumban midmiokardiálisan a T1 súlyozott és zsírelnyomásos felvételek, illetve az alacsony T1-mapping érték alapján zsíros átépülés, továbbá az inferior fal mentén szubepi-midmiokardiális fibrózisnak megfelelő kontraszthalmozás ábrázolódott. Az atípusos MR-kép alapján felmerült bal kamrai ACM, amit a genetikai vizsgálattal felfedezett Desmoplakin gén patogén mutációja igazolt. Eseteink rámutatnak arra, hogy ACM kétkamrás, illetve bal kamrai dominanciájú formáinak diagnózisában kiemelkedő szerepe lehet a szív-MR-nek és a genetikai vizsgálatnak.

A DNS-szekvenálási technológiákban bekövetkezett dinamikus fejlődésnek köszönhetően ismereteink számos kardiológiai betegség, így a cardiomyopathiák, az aritmiaszindrómák és az aortopathiák genetikai alapjainak megértésében is jelentősen bővültek az elmúlt években. A genetikai háttér jobb megértése mellett előrelépések történtek a kezelési lehetőségek terén is, amelyek megkövetelik a pontos diagnózisalkotást és a páciensek rizikóbecslését. A genetikai vizsgálatok integrációja a diagnosztikai eljárások sorába segít a prognózis meghatározásában és a személyre szabott klinikai menedzsment kialakításában. A genetikai vizsgálat célja a betegséget okozó mutáció azonosítása, majd a fokozott rizikójú családtagok preszimptomatikus vagy prediktív tesztelése. A kardiológus kulcsszerepet tölt be azon páciensek kiválasztásában, akik profitálhatnak a genetikai vizsgálatból, amihez elengedhetetlen a genetikai vizsgálatok alapjainak ismerete. Jelen összefoglaló közleményben rövid áttekintést adunk a gyakoribb örökletes kardiovaszkuláris betegségek genetikai hátteréről, a klinikai genetika általános szabályairól, a kardiogenetikai vizsgálat gyakorlati alkalmazásáról és bemutatjuk eddigi vizsgálati eredményeinket ezen betegcsoportokban.

Objectives To test the accuracy of TVS applying the IDEA approach for suspected rectosigmoid DE and to determine the frequency of other pelvic diseases mimicking DE in patients undergoing surgery. Materials und Methods Prospective single center observational study including consecutive women undergoing TVS for clinically suspected rectosigmoid DE followed by conservative or surgical therapy. TVS findings were compared with those obtained by laparoscopy and confirmed histologically. Results Of the 671 included patients, 128 women opted for medical therapy, and 6 patients decided for surgery but did not give consent to participate in the study. 537 women were enrolled in the final analysis. 279 (52 %) exhibited surgically confirmed rectosigmoid DE. The sensitivity and specificity, positive and negative predictive value (PPV, NPV), positive and negative likelihood ratio (LR+/–) and accuracy of TVS for diagnosing DE in the rectosigmoid were 93.5 %, 94.6 %, 94.9 %, 93.1 %, 17.24, 0.07, 94.04 %. 12 women who were clinically suspected for DE and mimicked sonographic signs fulfilling the IDEA criteria did exhibit other pathologies. Diagnoses were as follows: vaginal Gartner duct cyst (3/291;1.0 %), anorectal abscess (3/291; 1.0 %), rectal cancer (2/291;0.7 %), hydrosalpinx (2/291;0.7 %), metastatic endometrial cancer (1/291;0.35 %) and Crohn’s disease (1/291;0.35 %). Conclusion TVS for diagnosing colorectal DE applying the IDEA criteria is highly accurate for presurgical diagnosis. However, additional pelvic pathologies are encountered in 4–5 % of women attending for suspected rectosigmoid DE. These need to be taken into account when investigating patients for suspected DE.

Introduction: End-stage renal disease (ESRD) and acquired cystic kidney disease (ACKD) are known risk factors for renal cell carcinoma (RCC). Hereby, the clinicopathological features of RCCs developed in ESRD were investigated. Methods: A database consisting of 34 tumors from 31 patients with ESRD among 2 566 nephrectomy samples of RCC was built. The demographic, clinical, and follow-up data along with pathological parameters were analyzed. The RCCs were diagnosed according to the current WHO Classification of Urinary and Male Genital Tumors. Results: Twenty-two tumors developed in men and 12 in women, with a median age of 56 years (range: 27-75 years). The causes of ESRD were glomerulonephritis (n=7), hypertensive kidney disease (n=6), autosomal dominant polycystic kidney disease (n=6), chronic pyelonephritis (n=4), diabetic nephropathy (n=3), chemotherapy-induced nephropathy (n=1), and undetermined (n=4). ACKD complicated ESRD in 12 patients. The following histological subtypes were identified: clear cell RCC (n=19), papillary RCC (n=5), clear cell papillary tumor (n=5), ACKD RCC (n=3), and eosinophilic solid and cystic RCC (n=2). The median tumor size was 31 mm (range: 10-80 mm), and 32 tumors were confined to the kidney (pT1-pT2). There was no tumor-specific death during the period of this study. Progression was registered in one patient. Conclusion: In our cohort, the most common RCC subtype was clear cell RCC (55%), with a frequency that exceeded international data appreciably (14-25%). The incidence of clear cell papillary tumor and ACKD RCC (14.7% and 8.5%) was lower than data reported in the literature (30% and 40%). Our results indicate a favorable prognosis of RCC in ESRD.

RNA modifications play a fundamental role in cellular function. Pseudouridylation, the most abundant RNA modification, is catalyzed by the H/ACA small ribonucleoprotein (snoRNP) complex that shares four core proteins, dyskerin (DKC1), NOP10, NHP2, and GAR1. Mutations in DKC1 , NOP10 , or NHP2 cause dyskeratosis congenita (DC), a disorder characterized by telomere attrition. Here, we report a phenotype comprising nephrotic syndrome, cataracts, sensorineural deafness, enterocolitis, and early lethality in two pedigrees: males with DKC1 p.Glu206Lys and two children with homozygous NOP10 p.Thr16Met. Females with heterozygous DKC1 p.Glu206Lys developed cataracts and sensorineural deafness, but nephrotic syndrome in only one case of skewed X-inactivation. We found telomere attrition in both pedigrees, but no mucocutaneous abnormalities suggestive of DC. Both mutations fall at the dyskerin–NOP10 binding interface in a region distinct from those implicated in DC, impair the dyskerin–NOP10 interaction, and disrupt the catalytic pseudouridylation site. Accordingly, we found reduced pseudouridine levels in the ribosomal RNA (rRNA) of the patients. Zebrafish dkc1 mutants recapitulate the human phenotype and show reduced 18S pseudouridylation, ribosomal dysregulation, and a cell-cycle defect in the absence of telomere attrition. We therefore propose that this human disorder is the consequence of defective snoRNP pseudouridylation and ribosomal dysfunction.

Introduction Cardiovascular disease (CVD) is two to five times more prevalent in diabetic patients and is the leading cause of death. Therefore, identification of novel therapeutic strategies that reduce the risk of CVD is a research priority. Clinical trials showed that reduction in the relative risk of heart failure by sodium-glucose cotransporter 2 inhibitors (SGLT2i) are partly beyond their glucose lowering effects, however, the molecular mechanisms are still elusive. Here we investigated the role of SGLT2i dapagliflozin (DAPA) in the prevention of diabetes-induced cardiovascular complications. Methods Type 1 diabetes was induced with streptozotocin (65 mg/bwkg, ip.) in adult, male Wistar rats. Following the onset of diabetes rats were treated for six weeks with DAPA (1 mg/bwkg/day, po.). Results DAPA decreased blood glucose levels (D: 37±2.7 vs. D+DAPA: 18±5.6 mmol/L; p Conclusions These data support the preventive and protective role of SGLT2i in diabetes-associated cardiovascular disease. SGLT2i may provide novel therapeutic strategy to hinder the development of cardiovascular diseases in type 1 diabetes, thereby improve the outcomes.

Background: Behçet’s disease is an auto-inflammatory disorder categorized as a primer systemic vasculitis of unknown aetiology. Genetic factors, infectious agents and the irregularity of T-cell homeostasis are presumed to be responsible for the emergence of Behçet’s disease. Characteristic symptoms are multisystemic. Although cardiovascular involvement is rare, it should be noted due to the difficulty of surgical treatment options.Case Presentation: Our 44-year-old male patient underwent aortic valve replacement due to aortic regurgitation. At the 15-month follow-up, echocardiography showed detachment of the prosthetic valve and in the aortic root, multiple pseudo-aneurysms were identified. We performed an aortic root reconstruction with a Bentall procedure using a special „skirted” conduit to reduce strain in the suture line between the conduit and the extremely dilated left ventricular outflow tract. Conclusions: The surgical treatment of cardiovascular manifestations of Behçet’s disease remains challenging. This new technique may be beneficial in well-selected cases where the annulus of the aorta is extremely dilated or annular tissue disorder is present.

RNA modifications play a fundamental role in cellular function. Pseudouridylation, the most abundant RNA modification, is catalyzed by the H/ACA small ribonucleoprotein (snoRNP) complex that shares four core proteins, dyskerin (DKC1), NOP10, NHP2, and GAR1. Mutations in DKC1, NOP10, or NHP2 cause dyskeratosis congenita (DC), a disorder characterized by telomere attrition. Here, we report a phenotype comprising nephrotic syndrome, cataracts, sensorineural deafness, enterocolitis, and early lethality in two pedigrees: males with DKC1 p.Glu206Lys and two children with homozygous NOP10 p.Thr16Met. Females with heterozygous DKC1 p.Glu206Lys developed cataracts and sensorineural deafness, but nephrotic syndrome in only one case of skewed X-inactivation. We found telomere attrition in both pedigrees, but no mucocutaneous abnormalities suggestive of DC. Both mutations fall at the dyskerin–NOP10 binding interface in a region distinct from those implicated in DC, impair the dyskerin–NOP10 interaction, and disrupt the catalytic pseudouridylation site. Accordingly, we found reduced pseudouridine levels in the ribosomal RNA (rRNA) of the patients. Zebrafish dkc1 mutants recapitulate the human phenotype and show reduced 18S pseudouridylation, ribosomal dysregulation, and a cell-cycle defect in the absence of telomere attrition. We therefore propose that this human disorder is the consequence of defective snoRNP pseudouridylation and ribosomal dysfunction.

Background and Aims Pretransplant or de novo donor specific antibodies (DSA) may lead to active or chronic active antibody mediated rejection (a and cABMR) as leading cause of graft loss after kidney transplantation. There is no treatment protocol approved for ABMR. Anti Il-6 tocilizumab (TCZ), inhibitor of DSA production, is a potential approach to stabilize kidney allograft function, however, evidence based results are not available. In our retrospective case series analysis, we assessed the changes in DSA and eGFR during and at the end of treatment with TCZ. Method In our single center case series analysis, 10 kidney transplant patients with biopsy proven ABMR (aABMR 6, cABMR 4, age 43±10.5ys, 6 males, time since transplantation 18(2-119)months, 7 first transplant, serum creatinine 224±80 umol/L at baseline) were studied between January 2017 – June 2019. Total plasma exchange (PE) (5x) was followed by TCZ (8 mg/kg, 1x monthly for 6 months) in case of a and cABMR. Intravenous immunoglobulin (IVIG, 1gr/kg) was added in case of aABMR. Routine laboratory parameters and DSA were reported retrospectively. Results 6 aABMR patients completed the treatment protocol. Class I DSA decreased significantly (MFI 4457(635-14084) vs. 877(595-5678); p=0.007), but Class II DSA remained the same during the treatment (MFI 4725 (586-17615) vs. 8097 (671-14636) p=NS). eGFR of aABMR patients and 1 cABMR patient were stabilized. 3 cABMR patients returned to dialysis. Reversible elevation of liver transaminases were detected in three patients. There was no any serious adverse event recorded. Conclusion The opportunely timed TCZ seems to be effective in reducing Class I DSA and stabilize graft function in patients with aABMR. Further studies are needed to prove the long-term efficacy and the exact role of TCZ in cABMR among kidney transplant patients.

(1) Background: Successful treatment of acute kidney injury (AKI)-induced chronic kidney disease (CKD) is unresolved. We aimed to characterize the time-course of changes after contralateral nephrectomy (Nx) in a model of unilateral ischemic AKI-induced CKD with good translational utility. (2) Methods: Severe (30 min) left renal ischemia-reperfusion injury (IRI) or sham operation (S) was performed in male Naval Medical Research Institute (NMRI) mice followed by Nx or S one week later. Expression of proinflammatory, oxidative stress, injury and fibrotic markers was evaluated by RT-qPCR. (3) Results: Upon Nx, the injured kidney hardly functioned for three days, but it gradually regained function until day 14 to 21, as demonstrated by the plasma urea. Functional recovery led to a drastic reduction in inflammatory infiltration by macrophages and by decreases in macrophage chemoattractant protein-1 (MCP-1) and tumor necrosis factor-alpha (TNF-&alpha, ) mRNA and most injury markers. However, without Nx, a marked upregulation of proinflammatory (TNF-&alpha, IL-6, MCP-1 and complement-3 (C3)), oxidative stress (nuclear factor erythroid 2-related factor 2, NRF2) and fibrosis (collagen-1a1 (Col1a1) and fibronectin-1 (FN1)) genes perpetuated, and the injured kidney became completely fibrotic. Contralateral Nx delayed the development of renal failure up to 20 weeks. (4) Conclusion: Our results suggest that macrophage activation is involved in postischemic renal fibrosis, and it is drastically suppressed by contralateral nephrectomy ameliorating progression.

Back in 1995, a landmark paper was published, which shaped the fibrosis literature for many years to come. During the characterization of a fibroblast-specific marker (FSP1) in the kidneys, an observation was made, which gave rise to the hypothesis that “fibroblasts in some cases arise from the local conversion of epithelium.” In the following years, epithelial-mesenchymal transition was in the spotlight of fibrosis research, especially in the kidney. However, the hypothesis came under scrutiny following some discouraging findings from lineage tracing experiments and clinical observations. In this review, we provide a timely overview of the current position of the epithelial-mesenchymal transition hypothesis in the context of fibrosis (with a certain focus on renal fibrosis) and highlight some of the potential hurdles and pitfalls preventing therapeutic breakthroughs targeting fibrotic epithelial-mesenchymal transition.

The majority of prostate cancers require androgen hormones for growth, and androgen ablation is an important part of the systemic treatment of advanced prostate cancer. Nevertheless, most of these cancers eventually relapse as they become less sensitive to androgen ablation and anti-androgen treatment. Elucidating the molecular events that are responsible for the conversion of androgen-sensitive cancers to androgen-refractory tumors may reveal new therapeutic opportunities. In the present study, we investigated nine androgen-sensitive and nine androgen-refractory prostate cancer samples to evaluate the expression levels of 10 selected proteins that have been implicated in oncogenesis and cancer progression. Our immunohistochemical data show that three of the investigated proteins (i.e., minichromosome maintenance-2, methylguanine-DNA methyltransferase, and androgen receptor) are expressed at significantly different levels in the androgen-refractory cancer samples than in the androgen-sensitive tumors, whereas the expression levels of the seven other studied proteins (i.e., β-catenin, p27, p21, p16, Ki67, hypoxia-inducible factor 1 alpha, and geminin) are not significantly different regarding the two groups. Our data suggest that the increased expression of minichromosome maintenance-2 and decreased expression of methylguanine-DNA methyltransferase related to androgen receptor are indicative of the androgen-refractory stage in prostate cancer. Further studies are required to determine whether these expression changes play a causative role in the transition of androgen-sensitive to androgen-refractory prostate cancer.

Suppressor of cancer cell invasion (SCAI) has been originally characterized as a tumor suppressor inhibiting metastasis in different human cancer cells, and it has been suggested that SCAI expression declines in tumors. The expression patterns and role of SCAI during physiological and pathophysiological processes is still poorly understood. Earlier we demonstrated that SCAI is regulating the epithelial-mesenchymal transition of proximal tubular epithelial cells, it is downregulated during renal fibrosis and it is overexpressed in Wilms' tumors. Here we bring further evidence for the involvement of SCAI during cell plasticity and we examine the prognostic value and expression patterns of SCAI in various tumors. SCAI prevented the activation of the SMA promoter induced by angiotensin II. SCAI expression decreased in a model of endothelial-mesenchymal transition and increased during iPS reprogramming of fibroblasts. During renal fibrosis SCAI expression declined, as evidenced in a rat model of renal transplant rejection and in TGF-β1 overexpressing transgenic mice. High expression of SCAI correlated with better survival in patients with breast and lung cancers. Intriguingly, in the case of other cancers (gastric, prostate, colorectal) high SCAI expression correlated with poor survival of patients. Finally, we bring evidence for SCAI overexpression in colorectal cancer patients, irrespective of stage or metastatic status of the disease, suggesting a diverse role of SCAI in various diseases and cancer.

Autorii prezintă două cazuri de sindrom nefrotic cortico-rezistent cu debut în adolescenţă, cu manifestări clinice şi histopatologice similare (scleroză glomerulară focal-segmentală), dar cu mecanisme diferite de producere a proteinuriei: o formă dobândită şi una genetică, având astfel prognostic şi evoluţie diferită. Primul caz, o adolescentă de 16 ani prezintă debutul bolii brusc cu edeme masive, generalizate, cu răspuns favorabil la tratamentul cu ciclosporină. A doua pacientă, o adolescentă de 13 ani, a prezentat sindrom nefrotic corticorezistent cu debut insidios cu edeme uşoare. În acest caz testarea genetică a evidenţiat o mutaţie în gena WT1, iar evoluţia a fost rapidă (în 8 luni) către insuficienţă renală terminală, dar cu evoluţie şi prognostic favorabil după transplant renal. Concluzii: Formele genetice ale sindromului nefrotic nu răspund la tratamentul imunosupresiv şi pot evolua către boală renală terminală, dar după transplant recăderea este puţin probabilă, în contrast cu formele imune. Diagnosticul genetic precoce în sindromul nefrotic cortico-rezistent este important pentru managementul optim al pacienţilor, precizarea prognosticului, respectiv pentru consilierea genetică a familiei

Transforming growth factor-beta (TGFbeta)-induced epithelial-myofibroblast transdifferentiation is a central mechanism contributing to the pathogenesis of progressive tubulo-interstitial fibrosis. We wanted to dissect the role of extracellular signal-regulated protein kinase (ERK1,2), p38 mitogen-activated protein kinase (p38 MAPK) and the receptor-regulated Smad proteins in the regulation of alpha-smooth muscle cell actin (alphaSMA) expression, a hallmark of myofibroblast formation, induced by TGFbeta in renal proximal tubular cells.Activation of signalling molecules was assessed by western blotting using phospho-specific antibodies. To specifically interfere with signalling cascades, porcine proximal tubular cells (LLC-PK/AT1) were infected with recombinant replication-deficient adenoviruses. In other experiments, specific kinase inhibitors were used. The alphaSMA synthesis was assessed by western blotting or immunofluorescent staining of cellular alphaSMA. To assess the regulation of the alphaSMA promoter, tubular cells were transiently transfected with a 785 bp alphaSMA promoter-luciferase reporter construct and vectors interfering with the Smad pathway.Blocking ERK1,2 activation with PD98059 or p38 MAPK with SB 203580 potently inhibited the TGFbeta-induced alphaSMA synthesis in renal tubular cells. Adenoviral expression of dominant negative (DN) p38beta but not of p38alpha potently inhibited alphaSMA expression. Furthermore, adenoviral expression of DN MKK6b but not of DN MKK3b caused a substantial inhibition of the TGFbeta effect, confirming the role of p38beta in the regulation of TGFbeta-induced alphaSMA expression. Finally, inhibiting the Smad pathway with adenovirally delivered Smad7 and DN Smad3 also blocked TGFbeta-induced alphaSMA synthesis.TGFbeta-induced alphaSMA expression is regulated by the coordinated activation of a complex system of parallel MAPK and Smad signalling pathways in renal proximal tubular cells during epithelial-mesenchymal transdifferentiation.

The afferent arteriole (AA) is an important regulatory site of renal function and blood pressure. We have demonstrated endothelial fenestration and high permeability in the vicinity of renin granulated epithelioid cells in the juxtaglomerular portion of the afferent arteriole in different mammals. The permeability of fenestrated endothelium of afferent arteriole may be important in connection to various physiologic and pathophysiologic processes. We have assumed that the permeable fenestration may serve as a communication channel between the intravascular circulation and a pathway for renin secretion. Utilising the multiphoton image technique we were able to visualise the endothelial fenestration and renin granules of the in vitro microperfused AA and in vivo AA. We demonstrated that ferritin-positive, i.e., permeable portion of the afferent arteriole, under control conditions is on average 45 microm, which is about one-third to half of the total length of the afferent arteriole. The length of this portion is not constant and can change by physiologic and pharmacologic manipulation of renin formation. The permeability of the afferent arteriole is not changing only parallel with the pharmacologically stimulated renin secretion as already demonstrated in adult rats, but also with the change of renin appearance in afferent arteriole within the very first few days of life after birth. Independently from the age there is a significant correlation between the renin-positive and permeable portion of the AA. Further studies are necessary to clarify the physiological significance of afferent arteriolar permeability and its changes in the postnatal development of the kidney, as well as in correlation with activity of renin- angiotensin system.

Recent genetic analysis has identified a pivotal role of primary cilia in the pathogenesis of polycystic kidney disease (PKD). However, little is known regarding how cilia loss/dysfunction contributes to cyst development. In epithelial cells, changes in apical fluid flow induce cilia-mediated Ca2+entry via polycystin-2 (PC2), a cation channel. The Oak Ridge Polycystic Kidney ( orpk) mouse contains a mutated Tg737 gene that disrupts expression of polaris, a protein required for ciliogenesis. These studies examine the effect of cilia malformation on Ca2+entry in orpk cilia(−) collecting duct principal cells, and in orpk cells in which wild-type Tg737 was reintroduced, orpk cilia(+). [Ca2+]iwas monitored in confluent cell monolayers using fluorescence microscopy. Intrinsic apical Ca2+entry was measured by Mn2+quenching and Ca2+depletion/readdition under flow conditions below the threshold for stimulation. We found that unstimulated apical Ca2+entry was markedly increased in cilia(−) cells and was sensitive to Gd3+, an inhibitor of PC2. Electrophysiological measurements demonstrate increased abundance of an apical channel, consistent with PC2, in cilia(−) cells. Immunofluorescence studies revealed that PC2, normally expressed on and at the base of cilia in orpk cilia(+) cells, was observed throughout the apical membrane in cilia(−) cells. Furthermore, cilia(−) cells displayed elevated subapical Ca2+levels measured with the near-membrane Ca2+indicator FFP-18. We propose that cilia exert a tonic regulatory influence on apical Ca2+entry, and absence of cilia results in loss of spatial organization of PC2, causing unregulated Ca2+entry and elevations in subapical [Ca2+], a factor which may contribute to cyst formation.

Renin release from juxtaglomerular granular cells is considered the rate-limiting step in activation of the renin-angiotensin system that helps to maintain body salt and water balance. Available assays to measure renin release are complex, indirect, and work with significant internal errors. To directly visualize and study the dynamics of both the release and tissue activity of renin, we isolated and perfused afferent arterioles with attached glomeruli dissected from rabbit kidneys and used multiphoton fluorescence imaging. Acidotropic fluorophores, such as quinacrine and LysoTrackers, clearly and selectively labeled renin granules. Immunohistochemistry of mouse kidney with a specific renin antibody and quinacrine staining colocalized renin granules and quinacrine fluorescence. A low-salt diet for 1 wk caused an approximately fivefold increase in the number of both individual granules and renin-positive granular cells. Time-lapse imaging showed no signs of granule trafficking or any movement, only the dimming and disappearance of fluorescence from individual renin granules within 1 s in response to 100 μM isoproterenol. There appeared to be a quantal release of the granular contents; i.e., an all-or-none phenomenon. Using As4.1 cells, a granular cell line, we observed further classic signs of granule exocytosis, the emptying of granule content associated with a flash of quinacrine fluorescence. Using a fluorescence resonance energy transfer-based, 5-(2-aminoethylamino)naphthalene-1-sulfonic acid (EDANS)-conjugated renin substrate in the bath, an increase in EDANS fluorescence (renin activity) was observed around granular cells in response to isoproterenol. Fluorescence microscopy is an excellent tool for the further study of the mechanism, regulation, and dynamics of renin release.

Background. Angiotensin II (Ang II) down-regulates renin expression in juxtaglomerular cells, however, recent experimental evidence obtained in transgenic mice suggested that Ang II may ‘paradoxically’ increase transcriptional activity of the proximal renin promoter. Methods. To dissect signalling mechanisms contributing to the up-regulation of the proximal renin promoter by Ang II, porcine proximal tubular cells stably expressing the rabbit AT1 receptor (LLCPK/AT1) were transiently transfected with a luciferase reporter construct containing the 582 bp long piece of the human renin promoter. Activation of mitogenactivated protein kinases (MAPK) was detected by western blotting using phospho-MAPK-specific antibodies. Results. Ang II dose-dependently stimulated the transcriptional activity of the human renin promoter (10 � 7 M Ang II: 3.50±1.25-fold stimulation). In these cells Ang II activated both extracellular signalregulated kinase (ERK) and the c-Jun-N-terminal kinase (JNK). Inhibition of the ERK cascade did not reduce the stimulation of the renin promoter by Ang II, however, two expression vectors designed to inhibit the JNK pathway, the dominant negative JNK and the Jun-kinase interacting peptide inhibited the fold stimulation induced by Ang II (2.75±0.69 vs 1.6±0.23 and 1.8±0.34, respectively; P

Angiotensin (Ang) II directly stimulates epithelial sodium channel activity in the rabbit cortical collecting duct. Because Ang I and converting enzyme analogues might be present in the distal nephron, this raises the possibility of intraluminal generation of Ang II. Conversion of Ang I to Ang II was monitored by Ang II–dependent changes in intracellular sodium concentration as a reflection of sodium transport across the apical membrane. This involved imaging-based fluorescence microscopy with sodium-binding benzofuran isophthalate in isolated, perfused, cortical collecting-duct segments from rabbit kidney. Principal and intercalated cells were differentiated by rhodamine-conjugated peanut lectin. Control principal cell intracellular sodium concentration, during perfusion with 25 mmol/L NaCl and zero sodium in the bath plus monensin (10 −5 mol/L) averaged 5.8±0.14 mmol/L (n=156). The increase in intracellular sodium concentration, when luminal NaCl was increased from 25 to 150 mmol/L, was elevated by 3.5-fold in the presence of intraluminal Ang I (10 −6 mol/L). Also, the effects of Ang I on sodium transport were not significantly different from the effects of Ang II (10 −9 mol/L). Ang I was used in micromolar concentrations to ensure that there was sufficient substrate available for conversion to Ang II. Inhibition of the angiotensin-converting enzyme with captopril reduced the stimulatory effect of Ang I. These results suggest that intraluminal conversion of Ang I to Ang II can occur in the cortical collecting duct, resulting in enhanced apical sodium entry.

A 62-year-old female patient, symptomfree hematuria was found. Ultrasonography and computed tomography (CT) scan showed an endophytic mass on the medial pelvic wall on the solitary, right kidney. Nephrectomy was offered to the patient. Due to the solitary kidney, this would have meant lifelong hemodialysis for her. She refused nephroureterectomy but was ready to consider kidney-sparing operative solution. Therefore, percutaneous resection of the tumor, rather than nephroureterectomy was discussed. In order to decide such an operation, we had to prove with full certainty that there were no other small lesions in the pelvis. Noninvasive virtual pyeloscopy, rather than semirigid or flexible ureterorenoscopy, served this purpose.

During progressive tubulointerstitial fibrosis, renal tubular epithelial cells transform into α-smooth muscle actin (SMA)–expressing myofibroblasts via epithelial-to-mesenchymal transition (EMT). SMA expression is regulated by transforming growth factor (TGF)-β1 and cell contact disruption, through signaling events targeting the serum response factor–myocardin-related transcription factor (MRTF) complex. MRTFs are important regulators of fibrosis, tumor cell invasion, and metastasis. Consistent with the role of MRTFs in tumor progression, suppressor of cancer cell invasion (SCAI) was recently identified as a negative regulator of MRTF. Herein, we studied the role of SCAI in a fibrotic EMT model established on LLC-PK1 cells. SCAI overexpression prevented SMA promoter activation induced by TGF-β1. When co-expressed, it inhibited the stimulatory effects of MRTF-A, MRTF-B or the constitutive active forms of RhoA, Rac1, or Cdc42 on the SMA promoter. SCAI interfered with TGF-β1–induced SMA, connective tissue growth factor, and calponin protein expression; it rescued TGF-β1–induced E-cadherin down-regulation. IHC studies on human kidneys showed that SCAI expression is reduced during fibrosis. Kidneys of diabetic rats and mice with unilateral ureteral obstruction depicted significant loss of SCAI expression. In parallel with the decrease of SCAI protein expression, diabetic rat and mouse kidneys with unilateral ureteral obstruction showed SMA expression, as evidenced by using Western blot analysis. Finally, TGF-β1 treatment of LLC-PK1 cells attenuated SCAI protein expression. These data suggest that SCAI is a novel transcriptional cofactor that regulates EMT and renal fibrosis.

The members of the claudin family are major integral transmembrane protein constituents of tight junctions. Normal and neoplastic tissues can be characterized by unique qualitative and quantitative distribution of claudin subtypes, which may be related to clinicopathological features. Differential diagnosis and prognosis of nonmuscle invasive tumor entities of urinary bladder epithelium are often challenging. The aim was to investigate the expression profile of claudins in inverted urothelial papillomas (IUPs), urothelial papillomas (UPs), papillary urothelial neoplasms of low malignant potential (PUNLMPs), and intraepithelial (Ta), low-grade urothelial cell carcinomas (LG-UCCs) in order to reveal potential prognostic and differential diagnostic values of certain claudins. Claudin-1, -2, -4, and -7 protein expressions detected by immunohistochemistry and clinical data were analyzed in 15 IUPs, 20 UPs, 20 PUNLMPs, and 20 LG-UCCs. UPs, PUNLMPs, and LG-UCCs showed significantly decreased claudin-1 expression in comparison to IUPs. LG-UCCs expressing claudin-4 over the median were associated with significantly shorter recurrence-free survival. PUNLMPs expressing claudin-1 over the median revealed significantly longer recurrence-free survival. High claudin-1 protein expression might help to differentiate IUP from UPs, PUNLMPs, and LG-UCCs. High claudin-4 expression may determine an unfavorable clinical course of LG-UCCs, while high claudin-1 expression in PUNLMP was associated with markedly better clinical outcome.

While studying the intracellular calcium dynamics in cells of the macula densa, the observation was made that tubular epithelial cells located near the macula densa and associated with the renal arterioles exhibit spontaneous Ca2+ oscillations. In this study, the cortical thick ascending limb-distal tubule, with attached glomerulus, was isolated and perfused. At a low luminal sodium chloride concentration, Ca2+ oscillations at a frequency of 63 mHz were observed in tubular cells that were within 100 microm of the macula densa plaque using four-dimensional multiphoton microscopy and wide-field fluorescence microscopy with fura-2. The Ca2+ oscillations were absent in the macula densa cells. Spontaneous oscillations in basolateral membrane potential suggested that Ca2+ oscillations occurred, at least in part, through depolarization-induced increases in Ca2+ entry. The amplitude of these Ca2+ oscillations was significantly enhanced by the activation of the Ca2+-sensing receptor. Increasing the luminal sodium chloride concentration or luminal flow resulted in a significant increase in both the amplitude of Ca2+ oscillations and the intracellular Ca2+ concentration in perimacular cortical thick ascending limb cells. In addition, luminal furosemide attenuated the [NaCl]L-dependent changes in intracellular Ca2+ concentration, but hydrochlorothiazide had no effect. These findings demonstrate that tubular epithelial cells at the perimeter of the macula densa exhibit spontaneous oscillations in intracellular Ca2+ concentration, enhanced by tubular flow and luminal sodium chloride. These oscillatory patterns may play a role in juxtaglomerular signaling.

At the macula densa, flow-dependent changes in luminal composition lead to tubuloglomerular feedback and renin release. Apical entry of sodium chloride in both macula densa and cortical thick ascending limb (cTAL) cells occurs via furosemide-sensitive sodium-chloride-potassium cotransport. In macula densa, apical entry of sodium chloride leads to changes in cell volume, although there are conflicting data regarding the directional change in macula densa cell volume with increases in luminal sodium chloride concentration. To further assess volume changes in macula densa cells, cTAL-glomerular preparations were isolated and perfused from rabbits, and macula densa cells were loaded with fluorescent dyes calcein and 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene p-toluenesulfonate. Cell volume was determined with wide-field and multiphoton fluorescence microscopy. Increases in luminal sodium chloride concentration from 0 to 80 mmol/l at constant osmolality led to cell swelling in macula densa and cTAL cells, an effect that was blocked by luminal application of furosemide. However, increases in luminal sodium chloride concentration from 0 to 80 mmol/l with concomitant increases in osmolality caused sustained decreases in macula densa cell volume but transient increases in cTAL cell volume. Increases in luminal osmolality with urea also resulted in macula densa cell shrinkage. These studies suggest that, under physiologically relevant conditions of concurrent increases in luminal sodium chloride concentration and osmolality, there is macula densa cell shrinkage, which may play a role in the macula densa cell signaling process.

The Na+/Ca2+ exchangers, RNCX and SNCX, were cloned from mesangial cells of salt sensitive and salt resistant Dahl/Rapp rats, respectively, and differ at amino acid 218 (RNCXi/SNCXf) and in the exons expressed at the alternative splice site (RNCXB, D/SNCXB, D, F). These isoforms are also expressed in myocytes, neurons, and astrocytes where they maintain cytosolic calcium homeostasis. We demonstrated that cells expressing SNCX were more susceptible to oxidative stress than cells expressing RNCX. Others demonstrated that amyloid beta peptide (Abeta) augments the adverse effects of oxidative stress on calcium homeostasis. Therefore, we sought to assess the effect of Abeta 1-40 on the abilities of OK-PTH cells stably expressing RNCX and SNCX and human glioma cells, SKMG1, to regulate cytosolic calcium homeostasis. Our studies showed that Abeta 1-40 (1 microM) did not affect RNCX activity, as assessed by changes in [Ca2+]i (Delta[Ca2+]i, 260+/-10 nM to 267+/-8 nM), while stimulating exchange activity 2.4 and 3 fold in cells expressing SNCX (100+/-8 to 244+/-12 nM) and in SKMG1 cells (90+/-11 nM to 270+/-18 nM), respectively. Our results also showed that Abeta 1-40, while not affecting the rate of Mn2+ influx in cells expressing RNCX, stimulated the rate of Mn2+ influx 2.8 and 2.9 fold in cells expressing SNCX and in SKMG1 cells. Thus, our studies demonstrate that Abeta-induced cytosolic calcium increase is mediated through certain isoforms of the Na+/Ca2+ exchanger and reveals a possible mechanism by which Abeta 1-40 can alter cytosolic calcium homeostasis.

In the kidney, macula densa cells communicate with the mesangial cell-afferent arteriolar smooth muscle cell complex through ATP signaling. This signaling process involves release of ATP across the macula densa basolateral membrane through a maxi anion channel and the interaction of ATP with purinergic P2 receptors.

Functional and immunohistological studies were performed to identify basolateral chloride/bicarbonate exchange in macula densa cells. Using the isolated, perfused thick ascending limb with attached glomerulus preparation dissected from rabbit kidney, macula densa intracellular pH (pHi) was measured with fluorescence microscopy and BCECF. For these experiments, basolateral chloride was reduced, resulting in reversible macula densa cell alkalinization. Anion exchange activity was assessed by measuring the maximal net base efflux on readdition of bath chloride. Anion exchange activity required the presence of bicarbonate, was independent of changes in membrane potential, did not require the presence of sodium, and was inhibited by high concentrations of DIDS. Inhibition of macula densa anion exchange activity by basolateral DIDS increased luminal NaCl concentration-induced elevations in pHi. Immunohistochemical studies using antibodies against AE2 demonstrated expression of AE2 along the basolateral membrane of macula densa cells of rabbit kidney. These results suggest that macula densa cells functionally and immunologically express a chloride/bicarbonate exchanger at the basolateral membrane. This transporter likely participates in the regulation of pHiand might be involved in macula densa signaling.

Macula densa cells couple renal haemodynamics, glomerular filtration and renin release with tubular fluid salt and water reabsorption. These cells detect changes in tubular fluid composition through a complex of intracellular signalling events that are mediated by membrane transport pathways. Increases in luminal fluid sodium chloride concentration result in alterations in cell sodium chloride concentration, cytosolic calcium, cell pH, basolateral membrane depolarization and cell volume. Macula densa signalling then involves the production and release of specific paracrine signalling molecules at their basolateral membrane. Upon moderate increases in luminal sodium chloride concentration macula densa cells release increasing amounts of ATP and decreasing amounts of prostaglandin E 2 , thereby increasing afferent arteriolar tone and decreasing the release of renin from granular cells. On the other hand, further increases in luminal concentration stimulate the release of nitric oxide, which serve to prevent excessive tubuloglomerular feedback vasoconstriction. Paracrine signalling by the macula densa cells therefore controls juxtaglomerular function, renal vascular resistance and participates in the regulation of renin release.

One component of the macula densa (MD) tubuloglomerular feedback (TGF) signaling pathway may involve basolateral release of ATP through a maxi-anion channel. Release of ATP has previously been studied during a maximal luminal NaCl concentration ([NaCl]L) stimulus (20–150 mmol/l). Whether MD ATP release occurs during changes in [NaCl]Lwithin the physiological range (20–60 mmol/l) has not been examined. Also, because TGF is known to be enhanced by low dietary salt intake, we examined the pattern of MD ATP release from salt-restricted rabbits. Fluorescence microscopy, with fura 2-loaded cultured mouse mesangial cells as biosensors, was used to assess ATP release from the isolated, perfused thick ascending limb containing the MD segment. The mesangial biosensor cells, which contain purinergic receptors and elevate intracellular Ca2+concentration ([Ca2+]i) on ATP binding, were placed adjacent to the MD basolateral membrane. Elevations in [NaCl]Lbetween 0 and 80 mmol/l, in 20-mmol/l increments, caused stepwise increases in [Ca2+]i, with the highest increase at [NaCl]Lof ∼60 mmol/l. Luminal furosemide at 10−4mol/l blocked ATP release, which suggests that the efflux of ATP required MD Na-2Cl-K cotransport. A low-salt diet for 1 wk increased the magnitude of [NaCl]L-dependent elevations in biosensor [Ca2+]iby twofold, whereas high-salt intake had no effect. In summary, ATP release occurs over the same range of [NaCl]L(20–60 mmol/l) previously reported for TGF responses, and, similar to TGF, ATP release was enhanced by dietary salt restriction. Thus these two findings are consistent with the role of MD ATP release as a signaling component of the TGF pathway.

Renal epithelial cells release ATP constitutively under basal conditions and release higher quantities of purine nucleotide in response to stimuli. ATP filtered at the glomerulus, secreted by epithelial cells along the nephron, and released serosally by macula densa cells for feedback signaling to afferent arterioles within the glomerulus has important physiological signaling roles within kidneys. In autosomal recessive polycystic kidney disease (ARPKD) mice and humans, collecting duct epithelial cells lack an apical central cilium or express dysfunctional proteins within that monocilium. Collecting duct principal cells derived from an Oak Ridge polycystic kidney (orpk ( Tg737 ) ) mouse model of ARPKD lack a well-formed apical central cilium, thought to be a sensory organelle. We compared these cells grown as polarized cell monolayers on permeable supports to the same cells where the apical monocilium was genetically rescued with the wild-type Tg737 gene that encodes Polaris, a protein essential to cilia formation. Constitutive ATP release under basal conditions was low and not different in mutant versus rescued monolayers. However, genetically rescued principal cell monolayers released ATP three- to fivefold more robustly in response to ionomycin. Principal cell monolayers with fully formed apical monocilia responded three- to fivefold greater to hypotonicity than mutant monolayers lacking monocilia. In support of the idea that monocilia are sensory organelles, intentionally harsh pipetting of medium directly onto the center of the monolayer induced ATP release in genetically rescued monolayers that possessed apical monocilia. Mechanical stimulation was much less effective, however, on mutant orpk collecting duct principal cell monolayers that lacked apical central monocilia. Our data also show that an increase in cytosolic free Ca(2+) primes the ATP pool that is released in response to mechanical stimuli. It also appears that hypotonic cell swelling and mechanical pipetting stimuli trigger release of a common ATP pool. Cilium-competent monolayers responded to flow with an increase in cell Ca(2+) derived from both extracellular and intracellular stores. This flow-induced Ca(2+) signal was less robust in cilium-deficient monolayers. Flow-induced Ca(2+) signals in both preparations were attenuated by extracellular gadolinium and by extracellular apyrase, an ATPase/ADPase. Taken together, these data suggest that apical monocilia are sensory organelles and that their presence in the apical membrane facilitates the formation of a mature ATP secretion apparatus responsive to chemical, osmotic, and mechanical stimuli. The cilium and autocrine ATP signaling appear to work in concert to control cell Ca(2+). Loss of a cilium-dedicated autocrine purinergic signaling system may be a critical underlying etiology for ARPKD and may lead to disinhibition and/or upregulation of multiple sodium (Na(+)) absorptive mechanisms and a resultant severe hypertensive phenotype in ARPKD and, possibly, other diseases.