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R. Brian Doctor - One of the best experts on this subject based on the ideXlab platform.
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Distinct patterns of kidney and Liver Cyst growth in pkd2(WS25/−) mice
Nephrology dialysis transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association, 2010Co-Authors: R. Brian Doctor, Natalie J. Serkova, Kendra M. Hasebroock, Iram Zafar, Charles L. EdelsteinAbstract:Background. Autosomal dominant polyCystic kidney disease (ADPKD) is a common genetic disease that results in the development of Cystic kidneys and Liver. Pkd2(WS25/−) mice are a key genetic mouse model of human ADPKD that recapitulate the ‘molecular recessive’ nature of human ADPKD. Providing the foundation for future long-term studies, the present work documents distinct patterns of long-term Cyst growth in the kidneys and Liver of male and female pkd2(WS25/−) mice. Methods. Gravimetric measurements documented the progression of kidney and Liver growth in male and female pkd2(WS25/−) mice over 12 months. A fast imaging with steady-state precision–magnetic resonance imaging (FISP-MRI) technique to measure kidney and Liver organ and Cyst volumes was optimized and validated. Longitudinal FISP-MRI analyses of changes in Cyst volumes were performed in pkd2(WS25/−) mice over 15 months. Results. Male and female pkd2(WS25/−) mice had significant increases in kidney weights after 4 months of age. The progression of kidney growth was minimal after 4 months of age. Liver Cyst growth in male pkd2(WS25/−) mice was minimal after 4 months of age but showed an accelerated rate of growth after 8 months of age. Female pkd2(WS25/−) mice also showed accelerated growth but this was delayed in time when compared with male pkd2(WS25/−) mice. Conclusions. Pkd2(WS25/−) mice are a genetic mouse model that recapitulates the early phenotypic characteristics of human ADPKD kidney Cystogenesis. Male pkd2(WS25/−) mice consistently display a late progression in Liver growth that is seen in clinically impacted Livers of human ADPKD patients.
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Liver Cyst cytokines promote endothelial cell proliferation and development.
Experimental biology and medicine (Maywood N.J.), 2009Co-Authors: Kelley S. Brodsky, Ryan R. Mcwilliams, Claudia R. Amura, Nicholas P. Barry, R. Brian DoctorAbstract:Autosomal dominant polyCystic kidney (ADPKD) is highly prevalent genetic disease. Liver Cyst disease is the most common extrarenal manifestation in ADPKD and accounts for up to 10% of ADPKD morbidity and mortality. The clinical features of ADPKD Liver disease arise from dramatic increases in Liver Cyst volumes. To identify mechanisms that promote Liver Cyst growth, the present study characterized the degree of vascularization of Liver Cyst walls and determined that Cyst-specific cytokines and growth factors can drive endothelial cell proliferation and development. Microscopic techniques demonstrated Liver Cyst walls are well vascularized. A comparative analysis found the vascular density in free Liver Cyst walls was greater in mice than in humans. Treatment of human micro-vascular endothelial cells (HMEC-1) with human Liver Cyst fluid (huLCF) induced a rapid increase in vascular endothelium growth factor receptor 2 (VEGFR2) phosphorylation that persisted for 45-60 min and was blocked by 20 microM SU5416, a VEGFR tyrosine kinase inhibitor. Similarly, huLCF treatment of HMEC-1 cells induced an increase in the cell proliferation rate (131 +/- 6% of control levels; P > 0.05) and the degree of vascular development ('tube' diameter assay: 92 +/- 14 microm for huLCF vs. 12 +/- 7 microm for vehicle); P > 0.05). Both cell proliferation and vascular development were sensitive to SU5416. These studies indicate that factors secreted by Liver Cyst epithelia can activate VEGF signaling pathways and induce endothelial cell proliferation and differentiation. The present studies suggest that targeting VEGFR2-dependent angiogenesis may be an effective therapeutic strategy in blocking ADPKD Liver Cyst vascularization and growth.
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VEGF receptor inhibition blocks Liver Cyst growth in pkd2(WS25/−) mice
American journal of physiology. Cell physiology, 2007Co-Authors: Claudia R. Amura, Kelley S. Brodsky, Vincent H. Gattone, Rachel Groff, Norbert F. Voelkel, R. Brian DoctorAbstract:Proliferation of Cyst-lining epithelial cells is an integral part of autosomal dominant polyCystic kidney disease (ADPKD) Cyst growth. Cytokines and growth factors within Cyst fluids are positioned to induce Cyst growth. Vascular endothelial growth factor (VEGF) is a pleiotropic growth factor present in ADPKD Liver Cyst fluids (human 1,128 +/- 78, mouse 2,787 +/- 136 pg/ml) and, to a lesser extent, in ADPKD renal Cyst fluids (human 294 +/- 41, mouse 191 +/- 90 pg/ml). Western blotting showed that receptors for VEGF (VEGFR1 and VEGFR2) were present in both normal mouse bile ducts and pkd2(WS25/-) Liver Cyst epithelial cells. Treatment of pkd2(WS25/-) Liver Cyst epithelial cells with VEGF (50-50,000 pg/ml) or Liver Cyst fluid induced a proliferative response. The effect on proliferation of Liver Cyst fluid was inhibited by SU-5416, a potent VEGF receptor inhibitor. Treatment of pkd2(WS25/-) mice between 4 and 8 mo of age with SU-5416 markedly reduced the Cyst volume density of the Liver (vehicle 9.9 +/- 4.3%, SU-5416 1.8 +/- 0.7% of Liver). SU-5416 treatment between 4 and 12 mo of age markedly protected against increases in Liver weight [pkd2(+/+) 4.8 +/- 0.2%, pkd2(WS25/-)-vehicle 10.8 +/- 1.9%, pkd2(WS25/-)-SU-5416 4.8 +/- 0.4% body wt]. The capacity of VEGF signaling to induce in vitro proliferation of pkd2(WS25/-) Liver Cyst epithelial cells and inhibition of in vivo VEGF signaling to retard Liver Cyst growth in pkd2(WS25/-) mice indicates that the VEGF signaling pathway is a potentially important therapeutic target in the treatment of ADPKD Liver Cyst disease.
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Regulated ion transport in mouse Liver Cyst epithelial cells.
Biochimica et biophysica acta, 2006Co-Authors: R. Brian Doctor, Kelley S. Brodsky, Claudia R. Amura, Sylene M. Johnson, Vincent H. Gattone, J. Gregory FitzAbstract:Abstract Derived from bile duct epithelia (BDE), secretion by Liver Cyst-lining epithelia is positioned to drive Cyst expansion but the responsible ion flux pathways have not been characterized. Cyst-lining epithelia were isolated and cultured into high resistance monolayers to assess the ion secretory pathways. Electrophysiologic studies showed a marked rate of constitutive transepithelial ion transport, including Cl − secretion and Na + absorption. Na + absorption was amiloride-sensitive, suggesting the activation of epithelial sodium channels (ENaC). Further, both cAMP i and extracellular ATP induced robust secretory responses. Western blotting and immunohistologic analysis of Liver Cyst epithelia demonstrated expression of P2X4, a potent purinergic receptor in normal BDE. Luminometry and bioassaying measured physiologically relevant levels of ATP in a subset of Liver Cyst fluid samples. Liver Cyst epithelia also displayed a significant capacity to degrade extracellular ATP. In conclusion, regulated ion transport pathways are present in Liver Cyst epithelia and are positioned to direct fluid secretion into the lumen of Liver Cysts and promote increases in Liver Cyst expansion and growth.
Joost P.h. Drenth - One of the best experts on this subject based on the ideXlab platform.
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Liver Cyst gene knockout in cholangiocytes inhibits cilium formation and Wnt signaling.
Human molecular genetics, 2017Co-Authors: Edgar S Wills, Rene H. M. Te Morsche, Jeroen Van Reeuwijk, Nicola Horn, Iris Geomini, Liyanne F.m. Van De Laarschot, Dorus A. Mans, Marius Ueffing, Karsten Boldt, Joost P.h. DrenthAbstract:Mutations in the PRKCSH, SEC63 and LRP5 genes cause autosomal dominant polyCystic Liver disease (ADPLD). The proteins products of PRKCSH (alias GIIB) and SEC63 function in protein quality control and processing in the endoplasmic reticulum (ER), while LRP5 is implicated in Wnt/β-catenin signaling. To identify common denominators in the PLD pathogenesis, we mapped the PLD interactome by affinity proteomics, employing both HEK293T cells and H69 cholangiocytes. Identification of known complex members, such as glucosidase IIA (GIIA) for PRKCSH, and SEC61A1 and SEC61B for SEC63, confirmed the specificity of the analysis. GANAB, encoding GIIA, was very recently identified as an ADPLD gene. The presence of GIIA in the LRP5 complex pinpoints a potential functional connection with PRKCSH. Interestingly, all three PLD-associated protein complexes included filamin A (FLNA), a multifunctional protein described to play a role in ciliogenesis as well as canonical Wnt signalling. As ciliary dysfunction may also contribute to hereditary Liver Cyst formation, we evaluated the requirement of PRKCSH and SEC63 for ciliogenesis and Wnt signaling. By CRISPR/Cas9 induced knockdown of both ADPLD genes in HEK293T cells and H69 cholangiocytes, we identified that their depletion results in defective ciliogenesis. However, only H69 knockouts displayed reduced Wnt3a activation. Our results suggest that loss of PRKCSH and SEC63 leads to general defects in ciliogenesis, while quenching of the Wnt signaling cascade is cholangiocyte-restricted. Interactions of all three PLD-associated protein complexes with FLNA may mark a common link between the ADPLD proteins and the Cystogenic processes driving this disease.
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Boy with autosomal recessive polyCystic kidney and autosomal dominant polyCystic Liver disease
Pediatric Nephrology, 2012Co-Authors: Andrea Zingg-schenk, Joost P.h. Drenth, Carsten Bergmann, Jürg Caduff, Silvia Azzarello-burri, Thomas J. NeuhausAbstract:Background Autosomal recessive polyCystic kidney disease (ARPKD) shows a great phenotypic variability between patients, ranging from perinatal demise to mildly affected adults. Autosomal dominant polyCystic Liver disease (PCLD) does not manifest in childhood. Case-Diagnosis/Treatment A boy was reported with the co-occurrence of ARPKD and PCLD. He presented at the age of 16 days with pyelonephritis and urosepsis. Subsequent investigations showed enlarged kidneys and hyperechogenic renal medulla and Liver parenchyma. Genetic analysis revealed compound heterozygous mutations in the PKHD1 gene (p.Arg496X and p.Ser1862Leu). After his mother was diagnosed with PCLD, the finding of a Liver Cyst on ultrasound prompted analysis of the PRKCSH gene, revealing a missense mutation (p.Arg139His). At the most recent follow-up at 13 years of age, the patient’s course and clinical examination was uneventful with normal renal and Liver function without evidence of portal hypertension. Conclusions The patient with ARPKD and PCLD has so far demonstrated a benign clinical outcome, consistent with the great phenotypic variability of ARPKD and, apart from the Liver Cyst, asymptomatic manifestation of PCLD in childhood. However, close long-term follow-up is mandatory.
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HepatoCystin is not secreted in Cyst fluid of hepatoCystin mutant polyCystic Liver patients.
Journal of proteome research, 2008Co-Authors: Esmé Waanders, Anke L. L. Lameris, Huub J. M. Op Den Camp, Wendy Pluk, Jolein Gloerich, S. P. Strijk, Joost P.h. DrenthAbstract:Autosomal dominant polyCystic Liver disease (PCLD) is characterized by multiple Liver Cysts and is caused by mutations in PRKCSH (hepatoCystin). Mechanisms of Cystogenesis are unknown, but previous studies have shown that hepatoCystin is secreted in vitro. The goal of this study was to determine the fate of hepatoCystin in vivo. Using immunoprecipitation, we determined that mutant hepatoCystin is secreted from both apical and basolateral cell surface of MDCK cells stably transfected with mutant hepatoCystin. Analysis of 60 Cyst fluid samples from polyCystic Livers using Western blot, MALDI-TOF MS or nLC-MS/MS did not detect hepatoCystin in Liver Cyst fluid. We did identify 163 ubiquitous serum proteins. No paracrine or autocrine factors were recognized. Although Cyst fluids vary greatly in protein concentration, a PCLD specific protein pattern was not established. In conclusion, hepatoCystin is not secreted in PCLD Liver Cyst fluid, suggesting that mutant hepatoCystin is either not produced or degraded intracellularly. PCLD Cysts develop from intralobular bile ductules and Cyst fluid mainly contains common serum proteins comparable to that of other polyCystic diseases.
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laparoscopic fenestration of Liver Cysts in polyCystic Liver disease results in a median volume reduction of 12 5
Journal of Gastrointestinal Surgery, 2008Co-Authors: Loes Van Keimpema, Jelle P Ruurda, M F Ernst, Hendrikus J A A Van Geffen, Joost P.h. DrenthAbstract:Introduction Patients with polyCystic Liver disease (PCLD) may develop symptoms due to increased Liver volume. Laparoscopic fenestration is one of the options to reduce Liver volume and to relieve symptoms. This study was performed to evaluate the safety and efficacy of laparoscopic Liver Cyst fenestration.
Ken Tsuchiya - One of the best experts on this subject based on the ideXlab platform.
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Predicting Liver Cyst severity by mutations in patients with autosomal-dominant polyCystic kidney disease.
Hepatology international, 2021Co-Authors: Hiroshi Kataoka, Saki Watanabe, Masayo Sato, Shun Manabe, Shiho Makabe, Taro Akihisa, Yusuke Ushio, Naomi Iwasa, Rie Yoshida, Ken TsuchiyaAbstract:Most patients with autosomal-dominant polyCystic kidney disease (ADPKD) develop Liver Cysts and polyCystic Liver disease as they age. To date, no simple clinical indicator has been confirmed to predict polyCystic Liver disease exacerbation. Furthermore, the effect of the type and location of mutation on disease progression of polyCystic Liver disease remains unclear. Here, we aimed to establish a simple Liver Cyst indicator for clinical practice and investigate whether gene mutations determined Liver phenotype in patients with autosomal-dominant polyCystic kidney disease. In total, 129 patients with ADPKD were enrolled and Liver Cyst indicators were assessed based on mutation type (truncating mutation: nonsense, frameshift, and splicing mutation; non-truncating mutation: substitution) and mutation position. Liver Cyst severity was determined using Gigot and Drenth classifications, based on their number, maximum diameter, and area ratio with the Liver. We observed an overall prevalence of 62.8% for polyCystic Liver disease. Patients with PKD1 nonsense mutations, a type of PKD1 truncating mutation, exhibited more severe Liver disease phenotypes than those without the mutation. We identified maximum diameter as a potential Liver Cyst indicator. Moreover, a subgroup analysis that included a PKD1 nonsense mutation cohort revealed that genetic mutations located closer to the 5' end of PKD1 were associated with a maximum diameter index value ≥ 6 cm. PKD1 nonsense mutations were associated with Liver Cyst severity, which along with maximum diameter index as a simple clinical indicator for Liver Cysts, may improve the treatment of polyCystic Liver disease associated with ADPKD.
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Predicting Liver Cyst severity by mutations in patients with autosomal-dominant polyCystic kidney disease
Hepatology International, 2021Co-Authors: Hiroshi Kataoka, Saki Watanabe, Masayo Sato, Shun Manabe, Shiho Makabe, Taro Akihisa, Yusuke Ushio, Naomi Iwasa, Rie Yoshida, Ken TsuchiyaAbstract:Background Most patients with autosomal-dominant polyCystic kidney disease (ADPKD) develop Liver Cysts and polyCystic Liver disease as they age. To date, no simple clinical indicator has been confirmed to predict polyCystic Liver disease exacerbation. Furthermore, the effect of the type and location of mutation on disease progression of polyCystic Liver disease remains unclear. Here, we aimed to establish a simple Liver Cyst indicator for clinical practice and investigate whether gene mutations determined Liver phenotype in patients with autosomal-dominant polyCystic kidney disease. Methods In total, 129 patients with ADPKD were enrolled and Liver Cyst indicators were assessed based on mutation type (truncating mutation: nonsense, frameshift, and splicing mutation; non-truncating mutation: substitution) and mutation position. Liver Cyst severity was determined using Gigot and Drenth classifications, based on their number, maximum diameter, and area ratio with the Liver. Results We observed an overall prevalence of 62.8% for polyCystic Liver disease. Patients with PKD1 nonsense mutations, a type of PKD1 truncating mutation, exhibited more severe Liver disease phenotypes than those without the mutation. We identified maximum diameter as a potential Liver Cyst indicator. Moreover, a subgroup analysis that included a PKD1 nonsense mutation cohort revealed that genetic mutations located closer to the 5ʹ end of PKD1 were associated with a maximum diameter index value ≥ 6 cm. Conclusion PKD1 nonsense mutations were associated with Liver Cyst severity, which along with maximum diameter index as a simple clinical indicator for Liver Cysts, may improve the treatment of polyCystic Liver disease associated with ADPKD.
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The relationship between Liver Cyst volume and QOL in Japanese ADPKD patients.
Clinical and experimental nephrology, 2019Co-Authors: Satoru Muto, Ken Tsuchiya, Masahiko Ando, Saori Nishio, Kazushige Hanaoka, Yoshifumi Ubara, Ichiei Narita, Kouichi Kamura, Toshio Mochizuki, Kazuhiko TsuruyaAbstract:Background Although it is widely accepted that the autosomal dominant polyCystic kidney disease (ADPKD) patients with large Liver Cysts have a significant decrement in quality of life (QOL), there is insufficient evidence that clearly demonstrates the relationship between the size of the Liver Cysts and QOL. Therefore, we started this prospective longitudinal study to investigate the impact of Liver Cysts on QOL. Methods We grouped the 111 included ADPKD patients into 4 groups (control group A; 75%) according to Liver Cysts-parenchyma ratio (CPR). QOL was measured by FANLTC + FACT-Hep scores. We compared QOL scores and several clinical parameters amongst these groups for 3 years. Results The number of patients in group A, B, C, and D was 31, 14, 14, and 23, respectively. Although there were no significant differences in AST (p = 0.107), ALT (p = 0.925), and serum albumin (p = 0.212) between the four groups, platelet count was significantly decreased along with the extension of Cyst volume (p = 0.030). Overall, the mean FANLTC and FACT-Hep scores were 71.8 ± 12.5, and 32.4 ± 5.8, respectively. FANLTC (p = 0.017) and FACT-Hep scores (p = 0.003) were significantly decreased with increasing Cyst volume. From the data collected at the time of registration, multivariate linear regression analysis demonstrated that the CPR had a significant influence on FANLTC and FACT-Hep scores. Conclusion In this cross-sectional and prospective longitudinal study, we demonstrate the relationship between Liver Cyst volume and QOL in ADPKD patients. We hope to establish the long-term influence on QOL in this ongoing prospective longitudinal study.
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A case of a maintenance hemodialysis patient with autosomal dominant polyCystic kidney disease who underwent living donor Liver transplantation alone due to refractory Liver Cyst infection
CEN Case Reports, 2018Co-Authors: Taro Akihisa, Ken Tsuchiya, Ayami Ino, Hiroto Egawa, Yoshihito Kotera, Shunichi Ariizumi, Akiko Oomori, Shingo Yamashita, Yusuke Yamamoto, Masakazu YamamotoAbstract:Liver Cysts are observed in 83% of cases of autosomal dominant polyCystic kidney disease (ADPKD). Although not as prevalent as renal Cyst infection, Liver Cyst infection is a serious complication that is sometimes difficult to treat. We report the case of a maintenance hemodialysis patient with ADPKD who received a living donor Liver transplantation alone (LDLTA) due to refractory Liver Cyst infection. The patient was a 67-year-old Japanese man who developed fever and right-side abdominal pain, and Liver Cyst infection was suspected. Treatment with multiple antibiotics was ineffective. Many Liver Cysts were observed on magnetic resonance imaging scans and a Cyst in Liver segment S6, which produced the strongest signal variation, was drained. The fever subsided temporarily, but multiple infected Liver Cysts were observed on follow-up imaging examination; 4 months later, hepatectomy and LDLTA were performed. Although LDLTA due to refractory Liver Cyst infection in maintenance hemodialysis patients with ADPKD is risky and should be carefully considered, it may be the only effective treatment.
Claudia R. Amura - One of the best experts on this subject based on the ideXlab platform.
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Liver Cyst cytokines promote endothelial cell proliferation and development.
Experimental biology and medicine (Maywood N.J.), 2009Co-Authors: Kelley S. Brodsky, Ryan R. Mcwilliams, Claudia R. Amura, Nicholas P. Barry, R. Brian DoctorAbstract:Autosomal dominant polyCystic kidney (ADPKD) is highly prevalent genetic disease. Liver Cyst disease is the most common extrarenal manifestation in ADPKD and accounts for up to 10% of ADPKD morbidity and mortality. The clinical features of ADPKD Liver disease arise from dramatic increases in Liver Cyst volumes. To identify mechanisms that promote Liver Cyst growth, the present study characterized the degree of vascularization of Liver Cyst walls and determined that Cyst-specific cytokines and growth factors can drive endothelial cell proliferation and development. Microscopic techniques demonstrated Liver Cyst walls are well vascularized. A comparative analysis found the vascular density in free Liver Cyst walls was greater in mice than in humans. Treatment of human micro-vascular endothelial cells (HMEC-1) with human Liver Cyst fluid (huLCF) induced a rapid increase in vascular endothelium growth factor receptor 2 (VEGFR2) phosphorylation that persisted for 45-60 min and was blocked by 20 microM SU5416, a VEGFR tyrosine kinase inhibitor. Similarly, huLCF treatment of HMEC-1 cells induced an increase in the cell proliferation rate (131 +/- 6% of control levels; P > 0.05) and the degree of vascular development ('tube' diameter assay: 92 +/- 14 microm for huLCF vs. 12 +/- 7 microm for vehicle); P > 0.05). Both cell proliferation and vascular development were sensitive to SU5416. These studies indicate that factors secreted by Liver Cyst epithelia can activate VEGF signaling pathways and induce endothelial cell proliferation and differentiation. The present studies suggest that targeting VEGFR2-dependent angiogenesis may be an effective therapeutic strategy in blocking ADPKD Liver Cyst vascularization and growth.
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VEGF receptor inhibition blocks Liver Cyst growth in pkd2(WS25/−) mice
American journal of physiology. Cell physiology, 2007Co-Authors: Claudia R. Amura, Kelley S. Brodsky, Vincent H. Gattone, Rachel Groff, Norbert F. Voelkel, R. Brian DoctorAbstract:Proliferation of Cyst-lining epithelial cells is an integral part of autosomal dominant polyCystic kidney disease (ADPKD) Cyst growth. Cytokines and growth factors within Cyst fluids are positioned to induce Cyst growth. Vascular endothelial growth factor (VEGF) is a pleiotropic growth factor present in ADPKD Liver Cyst fluids (human 1,128 +/- 78, mouse 2,787 +/- 136 pg/ml) and, to a lesser extent, in ADPKD renal Cyst fluids (human 294 +/- 41, mouse 191 +/- 90 pg/ml). Western blotting showed that receptors for VEGF (VEGFR1 and VEGFR2) were present in both normal mouse bile ducts and pkd2(WS25/-) Liver Cyst epithelial cells. Treatment of pkd2(WS25/-) Liver Cyst epithelial cells with VEGF (50-50,000 pg/ml) or Liver Cyst fluid induced a proliferative response. The effect on proliferation of Liver Cyst fluid was inhibited by SU-5416, a potent VEGF receptor inhibitor. Treatment of pkd2(WS25/-) mice between 4 and 8 mo of age with SU-5416 markedly reduced the Cyst volume density of the Liver (vehicle 9.9 +/- 4.3%, SU-5416 1.8 +/- 0.7% of Liver). SU-5416 treatment between 4 and 12 mo of age markedly protected against increases in Liver weight [pkd2(+/+) 4.8 +/- 0.2%, pkd2(WS25/-)-vehicle 10.8 +/- 1.9%, pkd2(WS25/-)-SU-5416 4.8 +/- 0.4% body wt]. The capacity of VEGF signaling to induce in vitro proliferation of pkd2(WS25/-) Liver Cyst epithelial cells and inhibition of in vivo VEGF signaling to retard Liver Cyst growth in pkd2(WS25/-) mice indicates that the VEGF signaling pathway is a potentially important therapeutic target in the treatment of ADPKD Liver Cyst disease.
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Regulated ion transport in mouse Liver Cyst epithelial cells.
Biochimica et biophysica acta, 2006Co-Authors: R. Brian Doctor, Kelley S. Brodsky, Claudia R. Amura, Sylene M. Johnson, Vincent H. Gattone, J. Gregory FitzAbstract:Abstract Derived from bile duct epithelia (BDE), secretion by Liver Cyst-lining epithelia is positioned to drive Cyst expansion but the responsible ion flux pathways have not been characterized. Cyst-lining epithelia were isolated and cultured into high resistance monolayers to assess the ion secretory pathways. Electrophysiologic studies showed a marked rate of constitutive transepithelial ion transport, including Cl − secretion and Na + absorption. Na + absorption was amiloride-sensitive, suggesting the activation of epithelial sodium channels (ENaC). Further, both cAMP i and extracellular ATP induced robust secretory responses. Western blotting and immunohistologic analysis of Liver Cyst epithelia demonstrated expression of P2X4, a potent purinergic receptor in normal BDE. Luminometry and bioassaying measured physiologically relevant levels of ATP in a subset of Liver Cyst fluid samples. Liver Cyst epithelia also displayed a significant capacity to degrade extracellular ATP. In conclusion, regulated ion transport pathways are present in Liver Cyst epithelia and are positioned to direct fluid secretion into the lumen of Liver Cysts and promote increases in Liver Cyst expansion and growth.
Kelley S. Brodsky - One of the best experts on this subject based on the ideXlab platform.
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Liver Cyst cytokines promote endothelial cell proliferation and development.
Experimental biology and medicine (Maywood N.J.), 2009Co-Authors: Kelley S. Brodsky, Ryan R. Mcwilliams, Claudia R. Amura, Nicholas P. Barry, R. Brian DoctorAbstract:Autosomal dominant polyCystic kidney (ADPKD) is highly prevalent genetic disease. Liver Cyst disease is the most common extrarenal manifestation in ADPKD and accounts for up to 10% of ADPKD morbidity and mortality. The clinical features of ADPKD Liver disease arise from dramatic increases in Liver Cyst volumes. To identify mechanisms that promote Liver Cyst growth, the present study characterized the degree of vascularization of Liver Cyst walls and determined that Cyst-specific cytokines and growth factors can drive endothelial cell proliferation and development. Microscopic techniques demonstrated Liver Cyst walls are well vascularized. A comparative analysis found the vascular density in free Liver Cyst walls was greater in mice than in humans. Treatment of human micro-vascular endothelial cells (HMEC-1) with human Liver Cyst fluid (huLCF) induced a rapid increase in vascular endothelium growth factor receptor 2 (VEGFR2) phosphorylation that persisted for 45-60 min and was blocked by 20 microM SU5416, a VEGFR tyrosine kinase inhibitor. Similarly, huLCF treatment of HMEC-1 cells induced an increase in the cell proliferation rate (131 +/- 6% of control levels; P > 0.05) and the degree of vascular development ('tube' diameter assay: 92 +/- 14 microm for huLCF vs. 12 +/- 7 microm for vehicle); P > 0.05). Both cell proliferation and vascular development were sensitive to SU5416. These studies indicate that factors secreted by Liver Cyst epithelia can activate VEGF signaling pathways and induce endothelial cell proliferation and differentiation. The present studies suggest that targeting VEGFR2-dependent angiogenesis may be an effective therapeutic strategy in blocking ADPKD Liver Cyst vascularization and growth.
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VEGF receptor inhibition blocks Liver Cyst growth in pkd2(WS25/−) mice
American journal of physiology. Cell physiology, 2007Co-Authors: Claudia R. Amura, Kelley S. Brodsky, Vincent H. Gattone, Rachel Groff, Norbert F. Voelkel, R. Brian DoctorAbstract:Proliferation of Cyst-lining epithelial cells is an integral part of autosomal dominant polyCystic kidney disease (ADPKD) Cyst growth. Cytokines and growth factors within Cyst fluids are positioned to induce Cyst growth. Vascular endothelial growth factor (VEGF) is a pleiotropic growth factor present in ADPKD Liver Cyst fluids (human 1,128 +/- 78, mouse 2,787 +/- 136 pg/ml) and, to a lesser extent, in ADPKD renal Cyst fluids (human 294 +/- 41, mouse 191 +/- 90 pg/ml). Western blotting showed that receptors for VEGF (VEGFR1 and VEGFR2) were present in both normal mouse bile ducts and pkd2(WS25/-) Liver Cyst epithelial cells. Treatment of pkd2(WS25/-) Liver Cyst epithelial cells with VEGF (50-50,000 pg/ml) or Liver Cyst fluid induced a proliferative response. The effect on proliferation of Liver Cyst fluid was inhibited by SU-5416, a potent VEGF receptor inhibitor. Treatment of pkd2(WS25/-) mice between 4 and 8 mo of age with SU-5416 markedly reduced the Cyst volume density of the Liver (vehicle 9.9 +/- 4.3%, SU-5416 1.8 +/- 0.7% of Liver). SU-5416 treatment between 4 and 12 mo of age markedly protected against increases in Liver weight [pkd2(+/+) 4.8 +/- 0.2%, pkd2(WS25/-)-vehicle 10.8 +/- 1.9%, pkd2(WS25/-)-SU-5416 4.8 +/- 0.4% body wt]. The capacity of VEGF signaling to induce in vitro proliferation of pkd2(WS25/-) Liver Cyst epithelial cells and inhibition of in vivo VEGF signaling to retard Liver Cyst growth in pkd2(WS25/-) mice indicates that the VEGF signaling pathway is a potentially important therapeutic target in the treatment of ADPKD Liver Cyst disease.
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Regulated ion transport in mouse Liver Cyst epithelial cells.
Biochimica et biophysica acta, 2006Co-Authors: R. Brian Doctor, Kelley S. Brodsky, Claudia R. Amura, Sylene M. Johnson, Vincent H. Gattone, J. Gregory FitzAbstract:Abstract Derived from bile duct epithelia (BDE), secretion by Liver Cyst-lining epithelia is positioned to drive Cyst expansion but the responsible ion flux pathways have not been characterized. Cyst-lining epithelia were isolated and cultured into high resistance monolayers to assess the ion secretory pathways. Electrophysiologic studies showed a marked rate of constitutive transepithelial ion transport, including Cl − secretion and Na + absorption. Na + absorption was amiloride-sensitive, suggesting the activation of epithelial sodium channels (ENaC). Further, both cAMP i and extracellular ATP induced robust secretory responses. Western blotting and immunohistologic analysis of Liver Cyst epithelia demonstrated expression of P2X4, a potent purinergic receptor in normal BDE. Luminometry and bioassaying measured physiologically relevant levels of ATP in a subset of Liver Cyst fluid samples. Liver Cyst epithelia also displayed a significant capacity to degrade extracellular ATP. In conclusion, regulated ion transport pathways are present in Liver Cyst epithelia and are positioned to direct fluid secretion into the lumen of Liver Cysts and promote increases in Liver Cyst expansion and growth.