Sociodemographic characteristics and clinical features of patients with adult polycystic kidney disease undergoing hemodialysis

Aims:To analyze the socio-demographic and clinical characteristics of patients with adult polycystic kidney disease admitted to hemodialysis services in Northwestern Paraná state,Brazil. Methods: This was an observational, descriptive and retrospective longitudinal study. Medical records of patients with polycystic kidneys who initiated hemodialysis between 1995 and 2012, in four centers that treat patients of the coverage area of the 15th Regional Health Region of Paraná state where analyzed. Results:We found that 10.3% of hemodialysis patients had polycystic kidney disease as a leading cause of stage 5 of chronic kidney disease. The mean age of patients was 54.9±9.4 years (ranging between 27 and 74 years), with equal gender distribution and Caucasian predominance (72.9%). The average age of dialysis initiation was 50±10.2 years. The most common comorbidity was systemic hypertension (66.7%). Liver cyst was the main extra-renal manifestation (10.4%). Twenty-five percent of the patients required renal transplantation, and (22.9%) undergone nephrectomy. The most widely used classes of antihypertensive drugs were β-blockers (41.7%) and drugs that act on the renin-angiotensin system (31.3%), while 56.3% of patients were treated with recombinant human erythropoietin. Conclusions:This is a pioneering epidemiological study in Northwestern Paraná state. We found in this population a sociodemographic and clinical profile of adult polycystic kidney disease similar to that of North America and Europe, probably because the ethnic constitution of the sample was predominantly of Euro-descendants.

Clinical outcomes of kidney transplants on patients with end-stage renal disease secondary to lupus nephritis, polycystic kidney disease and diabetic nephropathy

Background: Patients with lupus nephritis could progress to endstage renal disease (10-22%); hence, kidney transplants should be considered as the treatment of choice for these patients. Objective: To evaluate the clinical outcomes after kidney transplants in patients with chronic kidney diseases secondary to lupus nephritis, polycystic kidney disease and diabetes nephropathy at Pablo Tobon Uribe Hospital. Methods: A descriptive and retrospective study performed at one kidney transplant center between 2005 and 2013. Results: A total of 136 patients, 27 with lupus nephritis (19.9%), 31 with polycystic kidney disease (22.8%) and 78 with diabetes nephropathy (57.4%), were included in the study. The graft survivals after one, three and five years were 96.3%, 82.5% and 82.5% for lupus nephritis; 90%, 86% and 76.5% for polycystic kidney disease and 91.7%, 80.3% and 67.9% for diabetes nephropathy, respectively, with no significant differences (p= 0.488); the rate of lupus nephritis recurrence was 0.94%/person-year. The etiology of lupus vs diabetes vs polycystic disease was not a risk factor for a decreased time of graft survival (Hazard ratio: 1.43; 95% CI: 0.52-3.93). Conclusion: Kidney transplant patients with end stage renal disease secondary to lupus nephritis has similar graft and patient survival success rates to patients with other kidney diseases. The complication rate and risk of recurrence for lupus nephritis are low. Kidney transplants should be considered as the treatment of choice for patients with end stage renal disease secondary to lupus nephritis.

Association of functional haem oxygenase-1 gene promoter polymorphism with polycystic kidney disease and IgA nephropathy

Background: Haem oxygenase-1 (HO-1) is a cytoprotective molecule that is reported to have a protective role in a variety of experimental models of renal injury. A functional dinucleotide repeat (GT)n polymorphism, within the HO-1 promoter, regulates HO-1 gene expression; a short number of repeats (S-allele <25) increases transcription. We report the first assessment of the role of this HO-1 gene promoter polymorphism in chronic kidney disease due to autosomal dominant polycystic kidney disease (ADPKD) and IgA nephropathy (IgAN).

Methods: The DNA from 160 patients (99% Caucasian) on renal replacement therapy (RRT) was genotyped. The primary renal disease was ADPKD in 100 patients and biopsy-proven IgAN in 60 patients.

Results: Overall, the mean age at commencement of RRT was not significantly different between patients with and without an S-allele (44.1 years versus 45.0 years, P = 0.64). In patients with ADPKD, the age at commencement of RRT was comparable regardless of the HO-1 genotype (47.7 years versus 46.7 years, P = 0.59). The same was true in patients with IgAN (38.3 years versus 42.2 years, P = 0.28).

Conclusion: This suggests that the functional HO-1 promoter polymorphism does not influence renal survival in CKD due to ADPKD or IgAN.

Tolvaptan in patients with autosomal dominant polycystic kidney disease

The course of autosomal dominant polycystic kidney disease (ADPKD) is often associated with pain, hypertension, and kidney failure. Preclinical studies indicated that vasopressin V(2)-receptor antagonists inhibit cyst growth and slow the decline of kidney function.

Optimising the management of polycystic kidney disease

Polycystic kidney disease (PKD) is the most common inherited renal disorder that results in chronic kidney disease. Clinical features include visible haematuria, loin pain, UTI and hypertension. The typical clinical course is a progressive increase in the number and size of renal cysts associated with gradual loss of kidney function (falling eGFR).

Pkd1 transgenic mice: Adult model of polycystic kidney disease with extrarenal and renal phenotypes

While high levels of Pkd1 expression are detected in tissues of patients with autosomal dominant polycystic kidney disease (ADPKD), it is unclear whether enhanced expression could be a pathogenetic mechanism for this systemic disorder. Three transgenic mouse lines were generated from a Pkd1-BAC modified by introducing a silent tag via homologous recombination to target a sustained wild type genomic Pkd1 expression within the native tissue and temporal regulation. These mice specifically overexpressed the Pkd1 transgene in extrarenal and renal tissues from approximately 2- to 15-fold over Pkd1 endogenous levels in a copy-dependent manner. All transgenic mice reproducibly developed tubular and glomerular cysts leading to renal insufficiency. Interestingly, Pkd1(TAG) mice also exhibited renal fibrosis and calcium deposits in papilla reminiscent of nephrolithiasis as frequently observed in ADPKD. Similar to human ADPKD, these mice consistently displayed hepatic fibrosis and approximately 15% intrahepatic cysts of the bile ducts affecting females preferentially. Moreover, a significant proportion of mice developed cardiac anomalies with severe left ventricular hypertrophy, marked aortic arch distention and/or valvular stenosis and calcification that had profound functional impact. Of significance, Pkd1(TAG) mice displayed occasional cerebral lesions with evidence of ruptured and unruptured cerebral aneurysms. This Pkd1(TAG) mouse model demonstrates that overexpression of wildtype Pkd1 can trigger the typical adult renal and extrarenal phenotypes resembling human ADPKD.

Autosomal dominant polycystic kidney disease in hemodialysis patients in southern Brazil

Introduction: Autosomal dominant polycystic kidney disease is the most common hereditary renal disease in humans. Objective: To examine the prevalence, clinical and laboratory characteristics of patients with polycystic kidneys and relate disease manifestations by gender. Methods: This was an observational and retrospective study. All the medical records of patients with polycystic kidneys who initiated hemodialysis between 1995 and 2012, in four centers that treat patients of the coverage area of the 15th regional health Paraná (Brazil), were analyzed. Results: The study included 48 patients with polycystic kidneys, the primary cause of stage 5 CKD. Disease prevalence was one in 10,912 people. The average age of dialysis initiation was 50.7 years and the follow-up time on dialysis until transplantation (36.5 months) was lower among men. Hypertension was the most frequent diagnosis in 73% of patients, predominantly in women (51.4%). The liver cyst was the most frequent extrarenal manifestations in men (60.0%). The death occurred in 10.4% of patients using hemodialysis, and 60% of men. The class of antihypertensive drug used was that acts on the renin-angiotensin system with higher frequency of use among women (53.3%). The post-dialysis urea was significantly higher in men. Conclusion: The prevalence of the disease is low among hemodialysis patients in southern Brazil. The differences observed between genders, with the exception of the post-dialysis urea, were not significant. The findings are different from those reported in North America and Europe.

Somatotroph pituitary adenoma with acromegaly and autosomal dominant polycystic kidney disease: SSTR5 polymorphism and PKD1 mutation

A 39-year-old woman with autosomal dominant polycystic kidney disease (ADPKD) presented with acromegaly and a pituitary macroadenoma. There was a family history of this renal disorder. She had undergone surgery for pituitary adenoma 6 years prior. Physical examination disclosed bitemporal hemianopsia and elevation of both basal growth hormone (GH) 106 ng/mL (normal 0-5) and insulin-like growth factor (IGF-1) 811 ng/mL (normal 48-255) blood levels. A magnetic resonance imaging scan disclosed a 3.0 cm sellar and suprasellar mass with both optic chiasm compression and left cavernous sinus invasion. Pathologic, cytogenetic, molecular and in silico analysis was undertaken. Histologic, immunohistochemical and ultrastructural studies of the lesion disclosed a sparsely granulated somatotroph adenoma. Standard chromosome analysis on the blood sample showed no abnormality. Sequence analysis of the coding regions of PKD1 and PKD2 employing DNA from both peripheral leukocytes and the tumor revealed the most common PKD1 mutation, 5014_5015delAG. Analysis of the entire SSTR5 gene disclosed the variant c.142C > A (p.L48M, rs4988483) in the heterozygous state in both blood and tumor, while no pathogenic mutations were noted in the MEN1, AIP, p27Kip1 and SSTR2 genes. To our knowledge, this is the fourth reported case of a GH-producing pituitary adenoma associated with ADPKD, but the first subjected to extensive morphological, ultrastructural, cytogenetic and molecular studies. The physical proximity of the PKD1 and SSTR5 genes on chromosome 16 suggests a causal relationship between ADPKD and somatotroph adenoma.

Molecular genetics of inherited cystic kidney diseases: new diagnostic approaches

Background. Hhereditary cystic kidney diseases are a heterogeneous spectrum of disorders leading to renal failure. Clinical features and family history can help to distinguish the recessive from dominant diseases but the differential diagnosis is difficult due the phenotypic overlap. The molecular diagnosis is often the only way to characterize the different forms. A conventional molecular screening is suitable for small genes but is expensive and time-consuming for large size genes. Next Generation Sequencing (NGS) technologies enables massively parallel sequencing of nucleic acid fragments. Purpose. The first purpose was to validate a diagnostic algorithm useful to drive the genetic screening. The second aim was to validate a NGS protocol of PKHD1 gene. Methods. DNAs from 50 patients were submitted to conventional screening of NPHP1, NPHP5, UMOD, REN and HNF1B genes. 5 patients with known mutations in PKHD1 were submitted to NGS to validate the new method and a not genotyped proband with his parents were analyzed for a diagnostic application. Results. The conventional molecular screening detected 8 mutations: 1) the novel p.E48K of REN in a patient with cystic nephropathy, hyperuricemia, hyperkalemia and anemia; 2) p.R489X of NPHP5 in a patient with Senior Loken Syndrome; 3) pR295C of HNF1B in a patient with renal failure and diabetes.; 4) the NPHP1 deletion in 3 patients with medullar cysts; 5) the HNF1B deletion in a patient with medullar cysts and renal hypoplasia and in a diabetic patient with liver disease. The NGS of PKHD1 detected all known mutations and two additional variants during the validation. The diagnostic NGS analysis identified the patient’s compound heterozygosity with a maternal frameshift mutation and a paternal missense mutation besides a not transmitted paternal missense mutation. Conclusions. The results confirm the validity of our diagnostic algorithm and suggest the possibility to introduce this NGS protocol to clinical practice.

[Hypophyseal incidentaloma in a patient with autosomal dominant polycystic kidney disease]

The prevalence of incidentally discovered lesions within the pituitary (pituitary incidentalomas) is about 10%. The most common form of sellar mass are clinically nonfunctioning adenomas (less than 10 mm); functioning adenomas, however, are rare. Incidentally discovered pituitary microadenomas causing growth hormone hypersecretion are uncommon. In addition, the association of autosomal dominant polycystic kidney disease with acromegaly is exceptional and has not yet been reported to our knowledge.

Sirolimus ameliorates the enhanced expression of metalloproteinases in a rat model of autosomal dominant polycystic kidney disease

BACKGROUND: Remodelling of matrix and tubular basement membranes (TBM) is a characteristic of polycystic kidney disease. We hypothesized that matrix and TBM degradation by metalloproteinases (MMPs) could promote cyst formation. We therefore investigated the renal expression of MMPs in the Han:SPRD rat model of autosomal dominant polycystic kidney disease (ADPKD) and examined the effect of sirolimus treatment on MMPs. METHODS: 5-week-old male heterozygous (Cy/+) and wild-type normal (+/+) rats were treated with sirolimus (2 mg/kg/day) through drinking water for 3 months. RESULTS: The mRNA and protein levels of MMP-2 and MMP-14 were markedly increased in the kidneys of heterozygous Cy/+ animals compared to wild-type +/+ as shown by RT-PCR and Western blot analyses for MMP-2 and MMP-14, and by zymography for MMP-2. Strong MMP-2 expression was detected by immunoperoxidase staining in cystic epithelial cells that also displayed an altered, thickened TBM. Tissue inhibitor of metalloproteinases-2 (TIMP-2) expression was not changed in Cy/+ kidneys. Sirolimus treatment leads to decreased protein expression of MMP-2 and MMP-14 in Cy/+, whereas MMP-2 and MMP-14 mRNA levels and TIMP-2 protein levels were not affected by sirolimus. CONCLUSION: In summary, in kidneys of the Han:SPRD rat model of ADPKD, there is a marked upregulation of MMP-2 and MMP-14. Sirolimus treatment was associated with a marked improvement of MMP-2 and MMP-14 overexpression, and this correlated also with less matrix and TBM alterations and milder cystic disease.