Telmisartan Ameliorates Fibrocystic Liver Disease in an Orthologous Rat Model of Human Autosomal Recessive Polycystic Kidney Disease

Human autosomal recessive polycystic kidney disease (ARPKD) produces kidneys which are massively enlarged due to multiple cysts, hypertension, and congenital hepatic fibrosis characterized by dilated bile ducts and portal hypertension. The PCK rat is an orthologous model of human ARPKD with numerous fluid-filled cysts caused by stimulated cellular proliferation in the renal tubules and hepatic bile duct epithelia, with interstitial fibrosis developed in the liver. We previously reported that a peroxisome proliferator activated receptor (PPAR)-γ full agonist ameliorated kidney and liver disease in PCK rats. Telmisartan is an angiotensin receptor blocker (ARB) used widely as an antihypertensive drug and shows partial PPAR-γ agonist activity. It also has nephroprotective activity in diabetes and renal injury and prevents the effects of drug-induced hepatotoxicity and hepatic fibrosis. In the present study, we determined whether telmisartan ameliorates progression of polycystic kidney and fibrocystic liver disease in PCK rats. Five male and 5 female PCK and normal control (+/+) rats were orally administered 3 mg/kg telmisartan or vehicle every day from 4 to 20 weeks of age. Treatment with telmisartan decreased blood pressure in both PCK and +/+ rats. Blood levels of aspartate amino transferase, alanine amino transferase and urea nitrogen were unaffected by telmisartan treatment. There was no effect on kidney disease progression, but liver weight relative to body weight, liver cystic area, hepatic fibrosis index, expression levels of Ki67 and TGF-β, and the number of Ki67- and TGF-β-positive interstitial cells in the liver were significantly decreased in telmisartan-treated PCK rats. Therefore, telmisartan ameliorates congenital hepatic fibrosis in ARPKD, possibly through the inhibition of signaling cascades responsible for cellular proliferation and interstitial fibrosis in PCK rats. The present results support the potential therapeutic use of ARBs for the treatment of fibrocystic liver disease in ARPKD patients.     

Polycystic liver disease presenting with an exudative pleural effusion: a case report

Introduction

Polycystic liver disease is asymptomatic in 95% of patients. In the remaining 5% it causes symptoms due to the local mass effect of the polycystic liver. We describe the case of a patient who presented with symptoms of a pleural effusion and was also found to have polycystic liver disease. The effusion recurred despite repeated efforts at drainage and only resolved following surgical debridement of the cystic liver.

Case presentation

A 50-year-old Caucasian woman presented with a two-week history of increasing dyspnoea. An examination revealed a large right pleural effusion and gross hepatomegaly. An ultrasound confirmed a large polycystic liver and diagnostic thoracocentesis revealed an exudate, which was sterile to culture. The pleural effusion proved refractory to drainage and our patient underwent surgery to deroof the main hepatic cysts in an attempt to reduce the pressure on her right diaphragm. The histology was compatible with that of polycystic liver disease. No evidence of malignancy was found. After surgery, our patient had no recurrence of her effusion and, to date, has remained asymptomatic from her polycystic liver disease.

Conclusion

The case in this report illustrates that an exudative pleural effusion is a rare complication of polycystic liver disease. We feel that the mechanical effects of a large polycystic liver, and subsequent disruption of sub-diaphragmatic capillaries, resulted in a persistent exudative pleural effusion. Thus, surgical debulking of the hepatic cysts is required to manage these effusions.     

多囊肝病的治疗及进展

多囊肝病(polycystic liver diseases,PLD)是一种罕见的遗传性疾病,囊肿可单独出现于肝脏(常染色体显性遗传性多囊肝病)或者合并肾脏囊肿(常染色体显性遗传性多囊肾病)。PLD是良性疾病,囊肿的体积和数量会持续不断的增长但肝脏功能不受影响。大部分患者无临床症状,无需治疗或仅需保守治疗。少数患者会因肝肿大占位效应或囊肿并发症而产生严重的临床症状时需要治疗,目的主要是减小肝脏的体积,治疗方法包括抽吸硬化术、开窗术、部分肝切除术、肝动脉栓塞术、肝脏移植术及药物治疗等。本文对PLD的治疗及进展进行综述。     

PPAR-gamma agonist ameliorates kidney and liver disease in an orthologous rat model of human autosomal recessive polycystic kidney disease

In autosomal recessive polycystic kidney disease (ARPKD), progressive enlargement of fluid-filled cysts is due to aberrant proliferation of tubule epithelial cells and transepithelial fluid secretion leading to extensive nephron loss and interstitial fibrosis. Congenital hepatic fibrosis associated with biliary cysts/dilatations is the most common extrarenal manifestation in ARPKD and can lead to massive liver enlargement. Peroxisome proliferator-activated receptor γ (PPAR-γ), a member of the ligand-dependent nuclear receptor superfamily, is expressed in a variety of tissues, including the kidneys and liver, and plays important roles in cell proliferation, fibrosis, and inflammation. In the current study, we determined that pioglitazone (PIO), a PPAR-γ agonist, decreases polycystic kidney and liver disease progression in the polycystic kidney rat, an orthologous model of human ARPKD. Daily treatment with 10 mg/kg PIO for 16 wk decreased kidney weight (% of body weight), renal cystic area, serum urea nitrogen, and the number of Ki67-, pERK1/2-, and pS6-positive cells in the kidney. There was also a decrease in liver weight (% of body weight), liver cystic area, fibrotic index, and the number of Ki67-, pERK1/2-, pERK5-, and TGF-β-positive cells in the liver. Taken together, these data suggest that PIO inhibits the progression of polycystic kidney and liver disease in a model of human ARPKD by inhibiting cell proliferation and fibrosis. These findings suggest that PPAR-γ agonists may have therapeutic value in the treatment of the renal and hepatic manifestations of ARPKD.     

Genetics and mechanisms of hepatic cystogenesis

Polycystic liver disease (PLD) is a heterogeneous genetic condition. PKD1 and PKD2 germline mutations are found in patients with autosomal dominant polycystic kidney disease (ADPKD). Autosomal dominant polycystic liver disease (ADPLD) is associated with germline mutations in PRKCSH, SEC63, LRP5, and recently ALG8 and SEC61. GANAB mutations are found in both patient groups. Loss of heterozygosity of PLD-genes in cyst epithelium contributes to the development of hepatic cysts. A genetic interaction network is implied in hepatic cystogenesis that connects the endoplasmic glycoprotein control mechanisms and polycystin expression and localization. Wnt signalling could be the major downstream signalling pathway that results in hepatic cyst growth. PLD in ADPLD and ADPKD probably results from changes in one common final pathway that initiates cyst growth. This article is part of a Special Issue entitled: Cholangiocytes in Health and Diseaseedited by Jesus Banales, Marco Marzioni, Nicholas LaRusso and Peter Jansen.     

Identification of a locus for autosomal dominant polycystic liver disease, on chromosome 19p13.2-13.1

Polycystic liver disease (PCLD) is characterized by the growth of fluid-filled cysts of biliary epithelial origin in the liver. Although the disease is often asymptomatic, it can, when severe, lead to complications requiring surgical therapy. PCLD is most often associated with autosomal dominant polycystic kidney disease (ADPKD); however, families with an isolated polycystic liver phenotype without kidney involvement have been described. The clinical presentation and histological features of polycystic liver disease in the presence or absence of ADPKD are indistinguishable, raising the possibility that the pathogenetic mechanisms in the diseases are interrelated. We ascertained two large families with polycystic liver disease without kidney cysts and performed a genomewide scan for genetic linkage. A causative gene, PCLD, was mapped to chromosome 19p13.2-13.1, with a maximum LOD score of 10.3. Haplotype analysis refined the PCLD interval to 12.5 cM flanked by D19S586/D19S583 and D19S593/D19S579. The discovery of genetic linkage will facilitate diagnosis and study of this underdiagnosed disease entity. Identification of PCLD will be instrumental to an understanding of the pathogenesis of cyst formation in the liver in isolated PCLD and in ADPKD.     

Sudden death caused by aortic dissection in a patient with polycystic kidney disease

A 43-year-old man presented at the emergency medical unit with chest pain. The results of a clinical examination were normal, apart from sternum pain (without radiation) on palpation. The patient had no respiratory problems and the pain was relieved by paracetamol. The electrocardiogram, laboratory tests and chest X-ray were normal. However, the man was found dead the next morning. In the autopsy, we noted the presence of haemopericardium, aortic dissection (starting from the vessel's origin and extended to the aortic arch and on through the diaphragm), polycystic kidney disease and liver cysts. In adult autosomal dominant polycystic kidney disease (ADPKD) patients, the main causes of death are ruptured intracerebral aneurysms, coronary artery disease, congestive heart failure, valvular heart disease and ruptured abdominal aortic aneurysms. Aortic dissection is considered to be rare cause of sudden death in ADPKD sufferers. ADPKD can have serious consequences for the vascular system. The families of confirmed ADPKD sufferers must be informed and screened as early as possible, in order to prevent renal and cardiovascular complications.     

Protein composition of liver cyst fluid from the BALB/c‐cpk/+ mouse model of autosomal recessive polycystic kidney disease

Cysts arising from hepatic bile ducts are a common extra‐renal pathology associated with polycystic kidney disease in humans. As an initial step in identifying active components that could contribute to disease progression, we have investigated the protein composition of hepatic cyst fluid in an orthologous animal model of autosomal recessive polycystic kidney disease, heterozygous (BALB/c‐cpk/+) mice. Proteomic analysis of cyst fluid tryptic digests using LC‐MS/MS identified 303 proteins, many of which are consistent with enhanced inflammatory cell processes, cellular proliferation, and basal laminar fibrosis associated with the development of hepatic bile duct cysts. Protein identifications have been submitted to the PRIDE database ( http://www.ebi.ac.uk/pride ), accession number 9227.     

Adult Polycystic Kidney Disease in a Rhesus Monkey (Macaca mulatta)

Adult polycystic kidney disease was diagnosed at necropsy in a 16-year-old rhesus monkey dead from renal failure. Both kidneys were enlarged and contained multiple cysts ranging from 0.1 to 4.0 cm in diameter. The age of onset of the clinical signs, terminal uremia, and the gross and histologic findings in this macaque were consistent with adult (type III) polycystic kidney disease of man.     

Multiple cyst formation in the liver and kidneys of a lion (<Emphasis Type="Italic">Panthera leo</Emphasis>): a case of polycystic kidney disease?

The present report describes the case of a 19-year-old male lion (Panthera leo) with polycystic lesions in liver and kidney. The animal suffered from inappetence and progressing hind limb weakness and was euthanized due to poor prognosis. Necropsy revealed multiple large, cystic cavities in the liver and numerous cysts in the renal cortex. Hepatic and renal cysts were lined by a flattened or cuboidal single-layered epithelium and derived from hepatic bile ducts and renal tubular structures, respectively, as confirmed by immunohistochemistry for the detection of different cytokeratins and carcinoembryonic antigen. Furthermore, a marked bile duct proliferation and fibrosis was found in the portal areas. Occasionally, renal cysts contained variable amounts of partly mineralized proteinaceous material, detached epithelial cells, and cellular debris. Additional findings included a moderate suppurative bronchopneumonia and other minor age-related degenerative changes. A mutation screen of exon 29 of the PKD1 gene did not reveal causative mutations like in domestic cats. This is the first report of polycystic kidney disease (PKD)-like lesions in a lion. The features of these lesions are similar to those of the adult-onset form of PKD in Persian cats.     

Structural and functional analyses of liver cysts from the BALB/c-cpk mouse model of polycystic kidney disease

Liver cysts arising from hepatic bile ducts are a common extra-renal pathology associated with both autosomal dominant and recessive polycystic kidney disease in humans. To elucidate the functional and structural changes inherent in cyst formation and growth, hepatic bile duct epithelia were isolated from the BALB/ c-cpk mouse model of polycystic kidney disease. Light and transmission electron microscopy revealed substantial fibrosis in the basal lamina surrounding hepatic bile duct cysts isolated from heterozygous (BALB/c-cpk/+) and homozygous (BALB/c-cpk/cpk) animals. Scanning electron microscopy and length analysis of normal, precystic and cystic bile ducts provided the unique observation that primary cilia in cholangiocytes isolated from bile ducts and cysts of animals expressing the mutated cpk gene had lengths outside the minimal and maximal ranges of those in cells lining bile ducts of wild-type animals. Based on the hypothesis that PKD is one of several diseases characterized as ciliopathies, this abnormal variability in the length of the primary cilia may have functional implications. Electrophysiological analyses of freshly isolated cysts indicate that the amiloride-sensitive epithelial Na(+) channel (ENaC) is inactive/absent and cAMP-mediated anion secretion is the electrogenic transport process contributing to cyst fluid accumulation. Anion secretion can be stimulated by the luminal stimulation of adenylyl cyclase.     

Proliferation-Independent Initiation of Biliary Cysts in Polycystic Liver Diseases

Biliary cysts in adult patients affected by polycystic liver disease are lined by cholangiocytes that proliferate, suggesting that initiation of cyst formation depends on proliferation. Here, we challenge this view by analyzing cyst-lining cell proliferation and differentiation in Cpk mouse embryos and in livers from human fetuses affected by Autosomal Recessive Polycystic Kidney Disease (ARPKD), at early stages of cyst formation. Proliferation of fetal cholangiocyte precursors, measured by immunostaining in human and mouse livers, was low and did not differ between normal and ARPKD or Cpk livers, excluding excessive proliferation as an initiating cause of liver cysts. Instead, our analyses provide evidence that the polycystic livers exhibit increased and accelerated differentiation of hepatoblasts into cholangiocyte precursors, eventually coalescing into large biliary cysts. Lineage tracing experiments, performed in mouse embryos, indicated that the cholangiocyte precursors in Cpk mice generate cholangiocytes and periportal hepatocytes, like in wild-type animals. Therefore, contrary to current belief, cyst formation in polycystic liver disease does not necessarily depend on overproliferation. Combining our prenatal data with available data from adult livers, we propose that polycystic liver can be initiated by proliferation-independent mechanisms at a fetal stage, followed by postnatal proliferation-dependent cyst expansion.     

PKHD1基因缺陷与常染色体隐性遗传性多囊肾病的研究进展

PKHD1是目前所知人类常染色体隐性遗传多囊肾病(autosomal recessive polycystic kidney disease,ARPKD)的惟一致病基因。ARPKD临床病变以双肾多发性进行性充液囊泡为主要特征。目前对PKHDl基因在ARPKD发病中的作用了解并不多。该文对ARPKD的发病机制和PKHD1基因功能最新研究进展进行综述。     

Perioperative Challenges and Surgical Treatment of Large Simple,and Infectious Liver Cyst - A 12-Year Experience

Background

Cystic lesions of the liver consist of a heterogeneous group of disorders that can present diagnostic and therapeutic challenges.

Methods

A retrospective review of all medical records of adult patients diagnosed with large (>7 cm) cystic lesions of the liver between January 2000 and December 2011, at Kurume University Hospital. Cases with polycystic disease were excluded.

Results

Twenty three patients were identified. The mean size was 13.9 cm (range, 7-22cm). The majority of simple cysts were found in women (females: males, 2: 21). In 19 patients, the cyst was removed surgically by wide deroofing (laparoscopically in 16 cases, combined with ethanol sclerotherapy in 13 cases). Infection of the liver cyst occurred in one patient, who later underwent central bi-segmentectomy.

Conclusion

Simple large cysts of the liver can be successfully treated by laparoscopic deroofing and alcohol sclerotherapy. Large hepatic cyst considered to need drainage should be removed surgically to avoid possible infection.     

Intraoperative Hyperglycemia during Liver Resection: Predictors and Association with the Extent of Hepatocytes Injury

Background

Patients undergoing liver resection are at risk for intraoperative hyperglycemia and acute hyperglycemia is known to induce hepatocytes injury. Thus, we aimed to evaluate whether intraoperative hyperglycemia during liver resection is associated with the extent of hepatic injury.

Methods

This 1 year retrospective observation consecutively enrolled 85 patients undergoing liver resection for hepatocellular carcinoma. Blood glucose concentrations were measured at predetermined time points including every start/end of intermittent hepatic inflow occlusion (IHIO) via arterial blood analysis. Postoperative transaminase concentrations were used as surrogate parameters indicating the extent of surgery-related acute hepatocytes injury.

Results

Thirty (35.5%) patients developed hyperglycemia (blood glucose > 180 mg/dl) during surgery. Prolonged (≥ 3 rounds) IHIO (odds ratio [OR] 7.34, P = 0.004) was determined as a risk factors for hyperglycemia as well as cirrhosis (OR 4.07, P = 0.022), lower prothrombin time (OR 0.01, P = 0.025), and greater total cholesterol level (OR 1.04, P = 0.003). Hyperglycemia was independently associated with perioperative increase in transaminase concentrations (aspartate transaminase, β 105.1, standard error 41.7, P = 0.014; alanine transaminase, β 81.6, standard error 38.1, P = 0.035). Of note, blood glucose > 160 or 140 mg/dl was not associated with postoperative transaminase concentrations.

Conclusions

Hyperglycemia during liver resection might be associated with the extent of hepatocytes injury. It would be rational to maintain blood glucose concentration < 180 mg/dl throughout the surgery in consideration of parenchymal disease, coagulation status, lipid profile, and the cumulative hepatic ischemia in patients undergoing liver resection for hepatocellular carcinoma.     

Animal models of polycystic kidney disease

Polycystic kidney disease (PKD) is one of the most prevalent causes of heritable renal failure. The disease is characterized by the occurrence of numerous fluid-filled cysts within the parenchyma of kidney. The cysts are epithelial in origin and expand in size, leading to crowding of normal kidney tissue. Ultimately, there is gross enlargement of the kidneys with loss of normal functions, and death usually occurs because of complications related to renal failure. Animal models of polycystic kidney disease are proving to be extremely useful for studying the molecular basis of renal cyst formation and for the isolation of genes carrying the mutations. This article describes the various animal models of polycystic kidney disease, spontaneously and experimentally derived, that have recently been identified.     

Clinical Correlates of Mass Effect in Autosomal Dominant Polycystic Kidney Disease

Mass effect from polycystic kidney and liver enlargement can result in significant clinical complications and symptoms in autosomal dominant polycystic kidney disease (ADPKD). In this single-center study, we examined the correlation of height-adjusted total liver volume (htTLV) and total kidney volume (htTKV) by CT imaging with hepatic complications (n = 461) and abdominal symptoms (n = 253) in patients with ADPKD. “Mass-effect” complications were assessed by review of medical records and abdominal symptoms, by a standardized research questionnaire. Overall, 91.8% of patients had 4 or more liver cysts on CT scans. Polycystic liver disease (PLD) was classified as none or mild (htTLV < 1,600 mL/m); moderate (1,600 ≤ htTLV <3,200 mL/m); and severe (htTLV ≥ 3,200 mL/m). The prevalence of moderate and severe PLD in our patient cohort was 11.7% (n = 54/461) and 4.8% (n = 22/461), respectively, with a female predominance in both the moderate (61.1%) and severe (95.5%) PLD groups. Pressure-related complications such as leg edema (20.4%), ascites (16.6%), and hernia (3.6%) were common, and patients with moderate to severe PLD exhibited a 6-fold increased risk (compared to no or mild PLD) for these complications in multivariate analysis. Similarly, abdominal symptoms including back pain (58.8%), flank pain (53.1%), abdominal fullness (46.5%), and dyspnea/chest-discomfort (44.3%) were very common, and patients with moderate to severe PLD exhibited a 5-fold increased risk for these symptoms. Moderate to severe PLD is a common and clinically important problem in ~16% of patients with ADPKD who may benefit from referral to specialized centers for further management.     

Effects of exposure to imidacloprid contaminated feed on the visceral organs of adult male rabbits (Oryctolagus cuniculus)

The best-known and often used systemic, broad-spectrum neonicotinoid pesticide is imidacloprid (IMI). This study was carried out on adult male rabbits (n = 12) to assess the residual effects of exposure to IMI-contaminated diet on the liver, lung, heart, and kidney. Pesticide-exposed rabbits (n = 6) received IMI contaminated green grass (Bildor® 0.5 ml (100 mg)/L water) every alternative day once daily for up to 15 days. The remaining rabbits were fed a standard diet free of pesticides as a control. During routine monitoring of the rabbits throughout the experiment, there were no apparent toxic symptoms identified. On days 16, after deep anesthesia blood and visceral organs were collected. The levels of hepatic serum aspartate transaminase and alanine transaminase were considerably elevated in IMI-exposed rabbits (p ≤ 0.05). Thin layer chromatography revealed that the residue of IMI was at the detectable level in the liver and stomach. Histopathologically, the liver revealed coagulation necrosis with granulomatous inflammation and congestion in portal areas with dilated and congested central veins. The lungs showed congestion of blood vessels and granulomatous inflammation around the terminal bronchiole. Accumulations of inflammatory cells were observed in the cortico-medullary junction in the kidney. The heart showed necrosis and infiltration of mononuclear cells within the cardiac muscles. The findings of the current study emphasize that IMI-contaminated feed exposure causes toxicity into the cellular level of different visceral organs of adult male rabbits and it may also cause the similar toxic effects of the other mammals specially the occupationally exposed persons.     

Polycystins, focal adhesions and extracellular matrix interactions

Polycystic kidney disease is the most common heritable disease in humans. In addition to epithelial cysts in the kidney, liver and pancreas, patients with autosomal dominant polycystic kidney disease (ADPKD) also suffer from abdominal hernia, intracranial aneurysm, gastrointestinal cysts, and cardiac valvular defects, conditions often associated with altered extracellular matrix production or integrity. Despite more than a decade of work on the principal ADPKD genes, PKD1 and PKD2, questions remain about the basis of cystic disease and the role of extracellular matrix in ADPKD pathology. This review explores the links between polycystins, focal adhesions, and extracellular matrix gene expression. These relationships suggest roles for polycystins in cell-matrix mechanosensory signaling that control matrix production and morphogenesis. This article is part of a Special Issue entitled: Polycystic Kidney Disease.