Reprogramming of Energy Metabolism in Human PKD1 Polycystic Kidney Disease: A Systems Biology Analysis.

Multiple alterations of cellular metabolism have been documented in experimental studies of autosomal dominant polycystic kidney disease (ADPKD) and are thought to contribute to its pathogenesis. To elucidate the molecular pathways and transcriptional regulators associated with the metabolic changes of renal cysts in ADPKD, we compared global gene expression data from human PKD1 renal cysts, minimally cystic tissues (MCT) from the same patients, and healthy human kidney cortical tissue samples. We found gene expression profiles of PKD1 renal cysts were consistent with the Warburg effect with gene pathway changes favoring increased cellular glucose uptake and lactate production, instead of pyruvate oxidation. Additionally, mitochondrial energy metabolism was globally depressed, associated with downregulation of gene pathways related to fatty acid oxidation (FAO), branched-chain amino acid (BCAA) degradation, the Krebs cycle, and oxidative phosphorylation (OXPHOS) in renal cysts. Activation of mTORC1 and its two target proto-oncogenes, HIF-1α and MYC, was predicted to drive the expression of multiple genes involved in the observed metabolic reprogramming (e.g., GLUT3, HK1/HK2, ALDOA, ENO2, PKM, LDHA/LDHB, MCT4, PDHA1, PDK1/3, MPC1/2, CPT2, BCAT1, NAMPT); indeed, their predicted expression patterns were confirmed by our data. Conversely, we found AMPK inhibition was predicted in renal cysts. AMPK inhibition was associated with decreased expression of PGC-1α, a transcriptional coactivator for transcription factors PPARα, ERRα, and ERRγ, all of which play a critical role in regulating oxidative metabolism and mitochondrial biogenesis. These data provide a comprehensive map of metabolic pathway reprogramming in ADPKD and highlight nodes of regulation that may serve as targets for therapeutic intervention.

Immunophenotypic analysis of angiomyolipoma with epithelial cysts, comparison to mixed epithelial and stromal tumors and epithelial and stromal elements of normal kidney and ovaries.

Angiomyolipoma with epithelial cysts (AMLEC) is a rare variant of renal angiomyolipoma (AML). It is characterized by a conventional AML component admixed with epithelial cysts within an "ovarian-like" stroma. Mixed epithelial and stromal tumor (MEST) is another renal neoplasm featuring epithelial cysts and "ovarian-like" stroma. While there is consensus that in MEST the epithelial and stromal components are neoplastic, in AMLEC it has been hypothesized that the epithelial component may represent renal tubular entrapment or ovarian-like transdifferentiation of tumor cells. The aim of this study was to compare the immunophenotypes of the epithelial-stromal components of AMLEC and MEST, with normal kidney and ovary to provide additional insights into the pathogenesis and relationships of these entities. In this study, we analyzed eight cases of AMLEC and 14 cases of MEST from 2003 to 2023. We used tissue microarrays, full sections, or unstained slides with an immunohistochemical panel including renal and ovarian markers: SF1, ER, PR, AR, PAX8, WT1, GATA3, CA-IX, p16, inhibin A, and BCL2. We compared these cases with ten non-neoplastic ovary and kidney samples. Our findings indicate that the epithelial component of AMLEC and MEST resembles hormone receptor positive renal tubular epithelium (AR + /ER - /PR -). AMLEC's stromal component resembled hormone receptor positive renal stroma, while MEST's resembled ovarian stroma, supporting mullerian transdifferentiation. Our study showed that the epithelial and stromal components of AMLEC and MEST are immunophenotypically different and also differ from normal tissues. Our findings suggest that in AMLEC, the epithelial-stromal component represents a hormonally driven proliferation of non-neoplastic renal elements within a dysregulated tumor microenvironment.

Clinicopathological characteristics and typing of multilocular cystic renal neoplasm of low malignant potential.

BACKGROUND: Up until now, no research has been reported on the association between the clinical growth rate of multilocular cystic renal neoplasm of low malignant potential (MCRNLMP) and computed tomography (CT) imaging characteristics. Our study sought to examine the correlation between them, with the objective of distinguishing unique features of MCRNLMP from renal cysts and exploring effective management strategies. AIM: To investigate optimal management strategies of MCRNLMP. METHODS: We retrospectively collected and analyzed data from 1520 patients, comprising 1444 with renal cysts and 76 with MCRNLMP, who underwent renal cyst decompression, radical nephrectomy, or nephron-sparing surgery for renal cystic disease between January 2013 and December 2021 at our institution. Detection of MCRNLMP utilized the Bosniak classification for imaging and the 2016 World Health Organization criteria for clinical pathology. RESULTS: Our meticulous exploration has revealed compelling findings on the occurrence of MCRNLMP. Precisely, it comprises 1.48% of all cases involving simple renal cysts, 5.26% of those with complex renal cysts, and a noteworthy 12.11% of renal tumors coexisting with renal cysts, indicating a statistically significant difference (P = 0.001). Moreover, MCRNLMP constituted a significant 22.37% of the patient population whose cysts demonstrated a rapid growth rate of ≥ 2.0 cm/year, whereas it only represented 0.66% among those with a growth rate below 2.0 cm/year. Of the 76 MCRNLMP cases studied, none of the nine patients who underwent subsequent nephron-sparing surgery or radical nephrectomy following renal cyst decompression experienced recurrence or metastasis. In the remaining 67 patients, who were actively monitored over a 3-year postoperative period, only one showed suspicious recurrence on CT scans. CONCLUSION: MCRNLMP can be tentatively identified and categorized into three types based on CT scanning and growth rate indicators. In treating MCRNLMP, partial nephrectomy is preferred, while radical nephrectomy should be minimized. After surgery, active monitoring is advisable to prevent unnecessary nephrectomy.

Renal cell carcinoma in an adult-onset ESRD patient with nephronophthisis harboring NPHP3 deletion: A case report.

Background: Nephronophthisis (NPHP) is a rare autosomal recessive inherited tubulointerstitial nephropathy, the most prevalent genetic cause of end-stage renal disease (ESRD) in children. Convincing evidence indicated that the overall prevalence of NPHP in adult-onset ESRD is very likely to be an underestimation. Therefore, understanding the genetic background and clinicopathologic features of adult-onset NPHP is warranted. Case presentation: we reported one intriguing case with concurrent NPHP3 c.2694-2_2694-1delAG (splicing) variant and c.1082C > G (p.S361C) variant. A 48-year-old male was admitted to our hospital, complained about renal dysfunction for 10 years, and found right renal space-occupying lesion for 1 week. One of the most interesting clinical features is adult-onset ESRD, which differs from previous cases. Another discovery of this study is that the NPHP harboring NPHP3 deletion may be associated with clear cell renal cell carcinoma. Conclusion: In conclusion, we report two mutations in the NPHP3 gene that cause NPHP with adult-onset ESRD and renal clear cell carcinoma in a Chinese family, enriching the clinical features of NPHP.

Renal Pathology of Ciliopathies.

Renal ciliopathies are a group of genetic disorders that affect the function of the primary cilium in the kidney, as well as other organs. Since primary cilia are important for regulation of cell signaling pathways, ciliary dysfunction results in a range of clinical manifestations, including renal failure, cyst formation, and hypertension. We summarize the current understanding of the pathophysiological and pathological features of renal ciliopathies in childhood, including autosomal dominant and recessive polycystic kidney disease, nephronophthisis, and Bardet-Biedl syndrome, as well as skeletal dysplasia associated renal ciliopathies. The genetic basis of these disorders is now well-established in many cases, with mutations in a large number of cilia-related genes such as PKD1, PKD2, BBS, MKS, and NPHP being responsible for the majority of cases. Renal ciliopathies are broadly characterized by development of interstitial fibrosis and formation of multiple renal cysts which gradually enlarge and replace normal renal tissue, with each condition demonstrating subtle differences in the degree, location, and age-related development of cysts and fibrosis. Presentation varies from prenatal diagnosis of congenital multisystem syndromes to an asymptomatic childhood with development of complications in later adulthood and therefore clinicopathological correlation is important, including increasing use of targeted genetic testing or whole genome sequencing, allowing greater understanding of genetic pathophysiological mechanisms.

First case of nodular dermatofibrosis with cystic renal disease in a beagle: An atypical case without FLCN gene mutation.

This report presents the first case of nodular dermatofibrosis with renal cysts (NDRC) in a beagle. In this atypical case, the gene mutation associated with the disease was not present, the renal cysts showed dynamic changes in size and number, and the patient has greatly surpassed the NDRC life expectation.

Late-onset Cholestasis with Paucity of Portal Area Secondary to HNF1ß Deficiency in Adulthood: A Case Report.

Hepatocyte nuclear factor 1ß (HNF1ß) is essential for biliary development, while its genetic defect triggers the dysplasia of interlobular bile ducts, leading to life-threatening hepatitis and cholestasis. To date, this disorder has mainly been documented in neonates. Here, we report a case of cholestasis in an adult patient caused by a de novo HNF1ß mutation. A liver biopsy revealed remarkable shrinkage of the portal area accompanied by a decrease or absence of interlobular bile ducts, veins, and arteries in the portal area. Our case showed that an HNF1ß defect could induce late-onset cholestasis with paucity of the portal area in adulthood.

Suspected Autosomal Recessive Polycystic Kidney Disease but Cerebellar Vermis Hypoplasia, Oligophrenia Ataxia, Coloboma, and Hepatic Fibrosis (COACH) Syndrome in Retrospect, A Delayed Diagnosis Aided by Genotyping and Reverse Phenotyping: A Case Report and A Review of the Literature.

The clinical features of cerebellar vermis hypoplasia, oligophrenia, ataxia, coloboma, and hepatic fibrosis (COACH) characterize the rare autosomal recessive multisystem disorder called COACH syndrome. COACH syndrome belongs to the spectrum of Joubert syndrome and related disorders (JSRDs) and liver involvement distinguishes COACH syndrome from the rest of the JSRD spectrum. Developmental delay and oculomotor apraxia occur early but with time, these can improve and may not be readily apparent or no longer need active medical management. Congenital hepatic fibrosis and renal disease, on the other hand, may develop late, and the temporal incongruity in organ system involvement may delay the recognition of COACH syndrome. We present a case of a young adult presenting late to a Renal Genetics Clinic for evaluation of renal cystic disease with congenital hepatic fibrosis, clinically suspected to have autosomal recessive polycystic kidney disease. Following genetic testing, a reevaluation of his medical records from infancy, together with reverse phenotyping and genetic phasing, led to a diagnosis of COACH syndrome.

A clinical review of congenital hepatic fibrosis diagnosed in adulthood: presentation, complications, and outcomes.

INTRODUCTION AND OBJECTIVES: Congenital hepatic fibrosis (CHF) is a rare condition characterized by biliary tract changes and a geographic pattern of liver fibrosis. Liver biopsy is essential to confirm its diagnosis. The absence of specific clinical indicators in adults often leads to delays in diagnosis and management, while the natural history has not been well described. We sought to define the presentation and outcomes of adults with biopsy-proven CHF. MATERIALS AND METHODS: A retrospective chart review was conducted of patients diagnosed with CHF by liver biopsy. Continuous variables were summarized with the sample median and range. Categorical variables were summarized with number and percentage of patients. RESULTS: We identified 24 patients evaluated over a 20-year period, with a median age of 51 years (range 22-72 years) at initial presentation; 14 were male. The most common imaging findings were renal cysts (91.3%), splenomegaly (69.6%), and a cirrhotic-appearing liver (60.9%). The most commonly treated liver-related complications were cholangitis (45.8%), varices (45.8%), and hepatic encephalopathy (25%). Two patients died with a median length of follow-up of 2.9 years (range: 0.0-20.0 years). Two patients underwent transjugular intrahepatic portosystemic shunt (TIPS) placement to manage bleeding esophageal varices. Eight patients underwent liver transplantation (LT), the most common indication being decompensated disease (50%). CONCLUSIONS: CHF should be considered when patients present with cholangitis and/or complications of portal hypertension and have a cirrhotic appearing liver and renal cysts on imaging. Depending upon the disease severity, interventions such as TIPS or LT may be required.

Clinical and molecular characteristics of two Italian kindreds with hypoparathyroidism, deafness and renal dysplasia (HDR) syndrome.

PURPOSE: Hypoparathyroidism, deafness, and renal dysplasia (HDR) syndrome, also known as Barakat syndrome, is a rare autosomal dominant disease characterized by the triad of hypoparathyroidism, deafness, and renal abnormalities. The disorder is caused by the haploinsufficiency of the zinc finger transcription factor GATA3 and exhibits a great clinical variability with an age-dependent penetrance of each feature. We report two unrelated kindreds whose probands were referred to our outpatient clinic for further evaluation of hypoparathyroidism. METHODS: The proband of family 1, a 17-year-old boy, was referred for severe hypocalcemia (5.9 mg/dL) incidentally detected at routine blood tests. Abdomen ultrasound showed bilateral renal cysts. The audiometric evaluation revealed the presence of bilateral moderate hearing loss although the patient could communicate without any problem. Conversely, the proband of family 2, a 19-year-old man, had severe symptomatic hypocalcemia complicated by epileptic seizure at the age of 14 years; his past medical history was remarkable for right nephrectomy at the age of 4 months due to multicystic renal disease and bilateral hearing loss diagnosed at the age of 18 years. RESULTS: Based on clinical, biochemical, and radiologic data, HDR syndrome was suspected and genetic analysis of the GATA3 gene revealed the presence of two pathogenetic variants in exon 3, c.404dupC and c.431dupG, in the proband of family 1 and 2, respectively. CONCLUSION: HDR syndrome is a rare cause of hypoparathyroidism and must be excluded in all patients with apparently idiopathic hypoparathyroidism. A correct diagnosis is of great importance for early detection of other HDR-related features and genetic counseling.

Loss of Muscle Mass in Delayed Diagnosis of Renal Cysts and Diabetes Syndrome: A Case Report.

Renal cysts and diabetes syndrome (RCAD) is a rare disease caused by abnormalities in the HNF1B gene, which often leads to dysfunction in the renal, genital tracts, and pancreas. In this report, we present a rare case of a 27-year-old female with muscle mass loss who experienced a delayed diagnosis of RCAD. The patient had been misdiagnosed as "type 1 diabetes" for a long period. Her main clinical manifestations included muscle loss, renal magnesium loss, and an incomplete longitudinal uterus. Ultimately, the diagnosis of RCAD syndrome was confirmed through genetic testing. Reduction of muscle mass, although rarely reported, can progress to sarcopenia. Therefore, early intervention should be strongly emphasized. Furthermore, in future research, it is crucial to explore the mechanisms and relationships underlying these patients and their unusual manifestations.

Ouabain enhances renal cyst growth in a slowly progressive mouse model of autosomal dominant polycystic kidney disease.

Renal cyst progression in autosomal dominant polycystic kidney disease (ADPKD) is highly dependent on agents circulating in blood. We have previously shown, using different in vitro models, that one of these agents is the hormone ouabain. By binding to Na+-K+-ATPase (NKA), ouabain triggers a cascade of signal transduction events that enhance ADPKD cyst progression by stimulating cell proliferation, fluid secretion, and dedifferentiation of the renal tubular epithelial cells. Here, we determined the effects of ouabain in vivo. We show that daily administration of ouabain to Pkd1RC/RC ADPKD mice for 1-5 mo, at physiological levels, augmented kidney cyst area and number compared with saline-injected controls. Also, ouabain favored renal fibrosis; however, renal function was not significantly altered as determined by blood urea nitrogen levels. Ouabain did not have a sex preferential effect, with male and female mice being affected equally. By contrast, ouabain had no significant effect on wild-type mice. In addition, the actions of ouabain on Pkd1RC/RC mice were exacerbated when another mutation that increased the affinity of NKA for ouabain was introduced to the mice (Pkd1RC/RCNKAα1OS/OS mice). Altogether, this work highlights the role of ouabain as a procystogenic factor in the development of ADPKD in vivo, that the ouabain affinity site on NKA is critical for this effect, and that circulating ouabain is an epigenetic factor that worsens the ADPKD phenotype.NEW & NOTEWORTHY This work shows that the hormone ouabain enhances the progression of autosomal dominant polycystic kidney disease (ADPKD) in vivo. Ouabain augments the size and number of renal cysts, the kidney weight to body weight ratio, and kidney fibrosis in an ADPKD mouse model. The Na+-K+-ATPase affinity for ouabain plays a critical role in these effects. In addition, these outcomes are independent of the sex of the mice.

CEUS Bosniak Classification-Time for Differentiation and Change in Renal Cyst Surveillance.

It is time for a change. CEUS is an established method that should be much more actively included in renal cyst monitoring strategies. This review compares the accuracies, strengths, and weaknesses of CEUS, CECT, and MRI in the classification of renal cysts. In order to avoid overstaging by CEUS, a further differentiation of classes IIF, III, and IV is required. A further development in the refinement of the CEUS-Bosniak classification aims to integrate CEUS more closely into the monitoring of renal cysts and to develop new and complex monitoring algorithms.

Non-suppression of renin by renal cysts in a subset of patients with primary aldosteronism-a prospective observational single center study.

BACKGROUND: Screening for primary aldosteronism is based on measuring aldosterone-to-renin ratio. Non-suppressed renin may cause false negative screening results, and such patients may miss focused, potentially curable treatment. We investigated the association between renal cysts and non-suppressed plasma renin. METHODS: Altogether, 114 consecutive patients with confirmed primary aldosteronism undergoing adrenal vein sampling were prospectively recruited between October 7, 2020 and December 30, 2021. During the procedure, plasma samples for renin analyses were collected from the right and left renal veins and the inferior vena cava. Renal cysts were identified using contrast-enhanced computed tomography. RESULTS: Renal cysts were found in 58.2% of the 114 patients. Neither screening nor renal vein renin concentrations were significantly different in patients with and without cysts, or when the kidneys with and without cysts were evaluated. However, cysts were significantly more prevalent in the "high-normal renin" group (cut point 23.0 mU/L) than in the "low to low-normal renin" group (90.9%, n = 11 vs. 56.0%, n = 102, P = .027, respectively). All patients ≤50 years of age in the "high-normal renin" group had renal cysts. Strong correlations were found between renin concentrations in the right and left renal veins (r = .984), and between renin concentration and renin activity in the inferior vena cava (r = .817). CONCLUSION: Renal cysts are found in the majority of patients with primary aldosteronism, and they may interfere with diagnostics, especially in patients aged 50 years or less. In patients with non-suppressed renin due to renal cysts, aldosterone-to-renin ratio below the diagnostic threshold does not always exclude the diagnosis of primary aldosteronism.

Bouveret's Syndrome: A Rare Form of Gallstone Ileus Caused by Large Renal Cysts.

Bouveret's syndrome is a rare variant of gallstone ileus caused by gastric outlet obstruction that arises from gallstones impacted in the distal stomach or proximal duodenum after passing through a cholecystoduodenal or cholecystogastric fistula. Simple kidney cysts are one of the most common lesions found in the elderly. They are usually asymptomatic, but the cysts can put pressure on the surrounding organs if they grow to large dimensions.This case report highlights a rare case of Bouveret's syndrome due to the presence of a large gallstone in the pyloric region that was caused by the creation of a cholecystogastric fistula from pressure exerted by two giant cysts of the right kidney.

The Modified Bosniak Classification for Intermediate and High-Risk Renal Cysts.

Background Renal cysts are uncommon among the pediatric population, and their transformation into malignant lesions is also uncommon. Early detection can prevent further complications and protect renal function. Bosniak classification is a computed tomography-based classification for renal cysts developed for adults. Children are more susceptible to CT radiation. Therefore, a modified Bosniak classification for children based on the ultrasound (US) can be used if it shows reliability and accuracy. Aim To apply the modified Bosniak classification system among children with renal cysts. Methods This was a retrospective study that was conducted on pediatric patients who underwent surgery for intermediate and high-risk complex renal cysts in Prince Sultan Military Medical City, Riyadh, Saudi Arabia using radiological information from 2009 to 2022. The collected data included demographics, medical history, radiological findings, and characteristics of renal cysts. SPSS Statistics v. 22 (IBM Corp., Armonk, NY) was used to analyze the data. Results There were 40 children included in the study based on the US-modified Bosniak classification. Around 26.3% of patients had class I and 39.5% had class II renal cysts. Histopathology showed that 10% had Wilms tumor, and 15% had benign lesions. There were significant correlations between pathology findings and US findings (p=0.004), and CT findings (p=0.016). Conclusion The modified Bosniak classification based on the US is sensitive, specific, and sufficiently accurate in the classification of renal cysts among children. Also, the size of the renal cysts can be a diagnostic marker of differentiation of benign and malignant cysts with high sensitivity and specificity.

Ciliary ARL13B inhibits developmental kidney cystogenesis in mouse.

ARL13B is a small GTPase enriched in cilia. Deletion of Arl13b in mouse kidney results in renal cysts and an associated absence of primary cilia. Similarly, ablation of cilia leads to kidney cysts. To investigate whether ARL13B functions from within cilia to direct kidney development, we examined kidneys of mice expressing an engineered cilia-excluded ARL13B variant, ARL13BV358A. These mice retained renal cilia and developed cystic kidneys. Because ARL13B functions as a guanine nucleotide exchange factor (GEF) for ARL3, we examined kidneys of mice expressing an ARL13B variant that lacks ARL3 GEF activity, ARL13BR79Q. We found normal kidney development with no evidence of cysts in these mice. Taken together, our results show that ARL13B functions within cilia to inhibit renal cystogenesis during mouse development, and that this function does not depend on its role as a GEF for ARL3.

Cystic Renal Masses: Old and New Paradigms.

Cystic renal masses describe a spectrum of lesions with benign and/or malignant features. Cystic renal masses are most often identified incidentally with the Bosniak classification system stratifying their malignant potential. Solid enhancing components most often represent clear cell renal cell carcinoma yet display an indolent natural history relative to pure solid renal masses. This has led to an increased adoption of active surveillance as a management strategy in those who are poor surgical candidates. This article provides a contemporary overview of historical and emerging clinical paradigms in the diagnosis and management of this distinct clinical entity.

Reprint of: lessons from histopathologic examination of nephrectomy specimens in patients with tuberous sclerosis complex: cysts, angiomyolipomas & renal cell carcinoma.

Renal manifestations in patients with tuberous sclerosis complex (TSC) include cysts, angiomyolipoma, and renal cell carcinoma. Unlike many hereditary predisposition syndromes, the spectrum of renal tumors in TSC patients (including both angiomyolipoma and renal cell carcinoma) is broad, with significant morphologic heterogeneity. An improved understanding of histopathologic findings in TSC patients and associated clinicopathologic correlates has significant implications not just in establishing a diagnosis of TSC, but also in the recognition of sporadic tumors occurring secondary to somatic alterations of TSC1/TSC2/MTOR pathway genes and accurate prognostication. In this review, we have discussed issues relevant to clinical management based on histopathologic findings in nephrectomy specimens from patients with TSC. This includes discussions related to screening for TSC, diagnosis of PKD1/TSC2 contiguous gene deletion syndrome, the morphologic spectrum of angiomyolipoma and renal epithelium-derived neoplasia, including the risk of disease progression.