Hypertension in autosomal dominant polycystic kidney disease

Hypertension occurs frequently in autosomal dominant polycystic kidney disease. Increased activity of the renin-angiotensin system contributes to the development and maintenance of hypertension before the development of renal failure. Angiotensin-converting enzyme inhibitors are indicated for treatment of hypertension before the development of renal failure, but in severe renal failure these agents may cause further deterioration in renal function. Treatment of hypertension may not retard the progression of renal failure but is necessary for the prevention of cardiovascular disease.     

Nephrotic syndrome in autosomal dominant polycystic kidney disease

Urinary protein excretion is generally less than 1 g/24 h in autosomal dominant polycystic kidney disease (ADPKD), and the association of the nephrotic syndrome with this condition is considered rare. A patient with ADPKD associated with nephrotic-range proteinuria is described. She exhibited a relatively rapid impairment of her renal function. An open renal biopsy revealed focal segmental glomerulosclerosis (FGS) with features consistent with secondary FGS. Twenty-one patients with ADPKD and nephrotic syndrome were retrieved from the literature. Fourteen of them (including this case) had a histopathologic evaluation, and FGS was the dominant diagnoses (five patients). Next in frequency were minimal-change disease and membranous nephropathy, with two patients each. Five other patients had a variety of diagnoses. Thus, it is difficult to ascertain if these associations are coincidental or represent a specific pathogenetic relationship. The evaluation of the data also suggests that the presence of proteinuria and nephrotic syndrome accelerates the course of ADPKD toward ESRD.     

Intracranial arterial dolichoectasia in autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is a systemic disorder with a variety of cardiovascular manifestations. This study presents a group of patients with ADPKD who had intracranial arterial dolichoectasia. One hundred seventy-eight ADPKD patients were screened with magnetic resonance angiography, 40 ADPKD patients had conventional angiography, and 98 ADPKD patients underwent a brain autopsy. For comparison, 360 patients without ADPKD who had magnetic resonance angiography and conventional angiography or brain autopsy were also studied. The prevalence of asymptomatic intracranial arterial dolichoectasia was 2.2% (4 of 178), 2.5% (1 of 40), and 2.0% (2 of 98) in the three ADPKD groups, respectively. None of the patients without ADPKD had intracranial arterial dolichoectasia. In addition to the seven patients with asymptomatic disease, two ADPKD patients with vertebrobasilar dolichoectasia had posterior circulation ischemic symptoms. The mean age of the nine patients (five men and four women) was 56.6 yr (range, 41 to 67 yr). The posterior circulation was involved in five patients, the anterior circulation was involved in two patients, and both were involved in two patients. Arterial dissection was believed to have caused middle cerebral artery dolichoectasia in one patient, and intracranial arterial dissections were strongly suspected in two other patients. Six of the nine patients with intracranial arterial dolichoectasia had additional vascular manifestations of ADPKD. Some patients with ADPKD are at an increased risk of developing intracranial arterial dolichoectasia and dissections. Recognizing this association is important because (1) it may be a cause of stroke; (2) it may mimic a saccular aneurysm on radiographic studies; and (3) it suggests that the arteriopathy of ADPKD may be more generalized than previously believed.     

Causes of death in autosomal dominant polycystic kidney disease

To determine the causes of death in autosomal dominant polycystic kidney disease (ADPKD) patients and to examine whether the extrarenal manifestations of ADPKD influence the causes of death, the medical records of 129 patients who died between 1956 and 1993 were reviewed; 58% of the 129 patients had an autopsy performed. Seventy-seven percent died after reaching ESRD. The mean age at death increased from 51 yr for those who died before 1975 to 59 yr for those who died after 1975, reflecting the introduction of renal replacement therapies. The most common cause of death before 1975 was infection (30%), followed by uremia (28%) and cardiac disease (21%); after 1975, these were cardiac disease (36%) and infection (24%). Infection was equally prevalent before and after 1975, presenting as sepsis in 94% and directly relating to ADPKD in 47% of these patients. Underlying factors for cardiac death were cardiac hypertrophy, seen in 89% of all autopsied patients, and coronary artery disease, seen in 81%. A neurologic event was the cause of death in 12% of patients; these were ruptured intracranial aneurysm in 6%, hypertensive intracranial hemorrhage in 5%, and ischemic stroke in 1%. The mean age of those who died of ruptured intracranial aneurysm was 37 yr. No patient died of renal cancer. Liver cysts were the most common extrarenal manifestation, seen in 70% of the autopsied cases; cysts in other organs were very rare. Colonic diverticula were found in 21%. Thus, the renal and extrarenal manifestations of ADPKD are important contributors to morbidity and mortality.     

Cardiovascular abnormalities in children with autosomal dominant polycystic kidney disease

It is known that adults with autosomal dominant polycystic kidney disease (ADPKD) have an increased incidence of cardiovascular abnormalities, including mitral valve prolapse. The cardiac manifestations of ADPKD in the pediatric population have not been well established. To determine the cardiac manifestations of children with ADPKD, echocardiography was performed in 154 children of 66 families in which one parent has ADPKD. Eighty-six affected children and 68 unaffected children were evaluated in a prospective, single-blinded manner by echocardiography. Affected children were defined as those with any cysts on a concurrent renal ultrasound or those predicted to be gene carriers by gene linkage analysis. A 12% incidence of mitral valve prolapse was found in the affected children compared with only 3% of the unaffected children (P < 0.05). ADPKD children, but not their unaffected siblings, demonstrate a significant correlation between left ventricular mass index and systolic blood pressure. Moreover, hypertensive ADPKD children have significantly larger left ventricular mass index than do normotensive ADPKD children. A 3.5% incidence of congenital heart disease was found in the affected group, whereas 2.9% of the unaffected children had congenital heart disease. It was concluded that systemic manifestations of ADPKD, particularly cardiovascular abnormalities, are present even in childhood and these warrant the clinician's attention.     

Genesis and significance of hypertension in autosomal dominant polycystic kidney disease

The aim of the present study was to determine whether U-50,488H and U-62,066E, kappa-opioid receptor agonists cause a neuroprotective action against hypoxia/hypoglycemia-induced reduction in 2-deoxyglucose (2-DG) uptake of hippocampal slices from U-50,488H-tolerant rats. Both U-50,488H and U-62,066E exhibited an attenuating effect on hypoxia/hypoglycemia-induced reduction in 2-DG uptake of hippocampal slices. Hypoxia/hypoglycemia-induced deficit of 2-DG uptake was prevented by cotreatment with naloxone, an opioid receptor antagonist, but potentiated by cotreatment with morphine, a mu-opioid receptor agonist. Chronic administration of U-50,488H resulted in the development of tolerance to the analgesic effect as well as the neuroprotective effect whereas this treatment affected neither basal- nor hypoxia/hypoglycemia-induced decreases in 2-DG uptake. Chronic administration of U-50,488H did not modify naloxone-induced attenuation of 2-DG uptake deficit but slightly potentiated the morphine-induced exacerbation. These findings suggest that the tolerance to kappa-opioid receptors does not affect the mu-opioid receptor-mediated neuroprotective or neurotoxic action.     

The prevalence of seminal vesicle cysts in autosomal dominant polycystic kidney disease

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is a systemic hereditary disorder characterized by bilateral diffuse renal cysts. Extrarenal involvement is a well known manifestation of ADPKD. Data relating to the association between seminal vesicle cysts and ADPKD are limited. The aims of this study are to evaluate the frequency of seminal vesicle cysts in ADPKD and to assess the relationship between seminal vesicle cysts, with cysts in the liver and prostate, and creatininaemia. METHODS: Forty five male patients (mean age 40 years, range 13-67) were included in the study. Each subject underwent a formal interview, physical examination; and abdominal and transrectal ultrasonography. Three patients were infertile, but one of the patients also had varicocele. RESULTS: Seminal vesicle cysts were present in 27 (60%) patients. Liver and prostate cysts were present in 19 (42%) and five (11%) patients, respectively. There was a positive correlation between seminal vesicle cysts, cysts in the liver, and serum creatinine concentrations. CONCLUSION: Our conclusions are: (i) seminal vesicle cysts are not uncommon in ADPKD; (ii) ADPKD should be looked for in patients with seminal vesicle cysts, and (iii) the clinical significance of seminal vesicle cysts in ADPKD remains to be defined.     

Factors relating to urinary protein excretion in children with autosomal dominant polycystic kidney disease

Adults with autosomal dominant polycystic kidney disease (ADPKD) who have overt proteinuria (>300 mg/d) have higher mean arterial pressures, lower creatinine clearances, larger renal volumes, and a more aggressive course of renal disease than ADPKD patients without proteinuria. This study examines the relationship between proteinuria and microalbuminuria and similar factors in ADPKD children. A total of 189 children from 81 ADPKD families was included in the analysis. The ADPKD children (n = 103) had significantly greater urine protein excretion rates than the non-ADPKD children (n = 86) (3.9+/-0.3 versus 2.8+/-0.2 mg/m2 per h, P < 0.001). Children with severe renal cystic disease (> 10 cysts; n = 54) had greater protein excretion than those with moderate disease (< or = 10 cysts; n = 49) (4.4+/-0.5 versus 3.3+/-0.2 mg/m2 per h, P < 0.05). The ADPKD children had significantly greater albumin excretion rates than the non-ADPKD children (32+/-6 versus 10+/-2 mg/m2 per 24 h, P < 0.001), and a higher percentage of ADPKD children had significant microalbuminuria (>15 mg/m2 per 24 h in boys and >23 mg/m2 per 24 h in girls) than their unaffected siblings (30% versus 10%, P < 0.05). Thirty percent of ADPKD children had albuminuria and 23% had overt proteinuria. For all ADPKD children, there was no correlation between proteinuria and hypertension. However, there was a significant correlation between urinary protein excretion and diastolic BP among children diagnosed after the first year of life (r = 0.23, P < 0.05). Therefore, proteinuria and albuminuria occur early in the course of ADPKD and may be markers of more severe renal disease.     

Acidic FGF regulation of hyperproliferation of fibroblasts in human autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by cystic tubule enlargement and expansion of the interstitium associated with fibrosis. Our previous studies have analyzed the increased proliferation of cystic epithelial cells and this study examines the basis of increased proliferation of interstitial fibroblasts associated with ADPKD disease progression. ADPKD fibroblasts show phenotypic alterations in vitro, have acquired the capacity to grow in soft agar, and show an increased mitogenic response to a variety of growth factors particularly acidic FGF (aFGF). ELISA, Western immunoblot analysis, and immunocytochemistry showed increased aFGF content in ADPKD tissues and fibroblasts in culture, and aFGF was secreted into the extracellular matrix and conditioned medium, respectively. No alterations in aFGF receptor number were found, but Scatchard analysis of 125I-aFGF binding suggested an increased affinity of binding to the low affinity receptor, and covalent cross-linking analysis suggested the presence of novel putative receptors (120 kDa) in ADPKD fibroblasts. Signaling abnormalities were found, since aFGF incubation resulted in the tyrosine phosphorylation of additional substrates, more rapidly and for a more sustained duration in ADPKD fibroblasts than in normal fibroblasts. These findings suggest an important role for acidic FGF in the hyperproliferation of interstitial fibroblasts associated with disease progression in human ADPKD.     

Role and long-term results of laparoscopic decortication in solitary cystic and autosomal dominant polycystic kidney disease

PURPOSE: Access to retroperitoneal structures via the laparoscope has become established for various conditions. This minimally invasive approach has distinct advantages over conventional open surgery. We document our experience with laparoscopic cyst decortication for diseases of the kidney, including simple and complex cysts, multiple cysts and autosomal dominant polycystic kidney disease. MATERIALS AND METHODS: We retrospectively reviewed the records of 17 patients who underwent a total of 20 procedures. Cases were categorized as polycystic kidney disease and nonpolycystic kidney disease. Factors analyzed were estimated blood loss, length of surgical procedure, hospital stay and complications. Followup included radiographic studies (computerized tomography and/or renal sonography) and patient subjective pain relief, as determined by clinical records and telephone interview. RESULTS: Nine and 11 procedures were done for nonpolycystic kidney disease and polycystic kidney disease, respectively. Of the 8 patients with polycystic kidney disease 3 underwent repeat procedures. Followup was 3 to 63 months (average 26). All patients with simple cysts who were treated for pain were pain-free at the latest followup. Of the 10 procedures 9 (90%) performed for pain relief in polycystic kidney disease successfully produced immediate pain relief. Pain-free status decreased with time with 7 of 8 (87.5%) pain-free after 6 months, and 5 of 7 (71.4%) at 1, 4 of 6 (66.7%) at 2 and 1 of 4 (25%) at 3 years. A repeat operation successfully relieved recurrent pain in 2 of 3 cases (66.7%). Of the 7 patients with polycystic kidney disease who underwent surgery for pain relief 5 (71%) are currently pain-free. CONCLUSIONS: Laparoscopic renal cyst decortication is an effective minimally invasive treatment for painful simple cysts. It is also effective for short to intermediate pain relief in autosomal dominant polycystic kidney disease. Long-term followup suggests that a repeat procedure may be necessary to maintain adequate control of symptoms in polycystic kidney disease.     

Anticipation of age at renal death in autosomal dominant polycystic kidney disease (ADPKD)?

It has been claimed that anticipation occurs in ADPKD, i.e. endstage renal failure at progressively earlier age in successive generations. This observation might possibly point to unstable DNA as the molecular basis of ADPKD. We analysed 74 parent-offspring pairs of 148 families in Germany and Austria in whom (i) ADPKD was verified by appropriate imaging procedures and (ii) age at renal death was accurately known. The median difference for age at renal death between parent and offspring was 0 years, range -26.3 to +27.2 years. There was no deviation from normal (Gaussian) distribution according to the Shapiro-Wilk test (P = 0.75). We conclude that systematic anticipation cannot be demonstrated with this sample which had sufficient size for meaningful biostatistical analysis.     

Study of prognostic factors for renal function in patients with autosomal dominant polycystic kidney disease

To examine clinical features and the prognostic factors for renal function in patients with autosomal dominant polycystic kidney disease (ADPKD), a total of 118 patients (60 men and 58 women) were followed for 3 to 192 months (mean 77 months). The mean age of men at the diagnosis of ADPKD was younger than that of women. Main Symptoms were hematuria, hypertension and proteinuria. Forty-one % of the patients showed deterioration of renal function at the diagnosis. The rate of residual volume of renal parenchyma on CT findings was correlated well with renal function. Twenty-eight % of the patients preserved good and stable renal functions for over 5 years, while most of others had deterioration in their renal function. Thirty-four % of the patients started dialysis within 79 +/- 62 months from the diagnosis. The frequency of end stage renal failure was 7% at 40 years, 21% at 50 years, 36% at 60 years and 63% at 70 years old, respectively. Men needed hemodialysis at younger ages than women. Renal function of the patients with hypertension was worse than that of the patients without hypertension. The ratio of the value of P.S.P.120 to that of serum creatinine (PSP120/sCr), and the rate of residual volume of renal parenchyma revealed distinct prognostic factors for renal function.     

Frequency and impact of autosomal dominant polycystic kidney disease in the Seychelles (Indian Ocean)

BACKGROUND: As little such data is available in African populations, we investigated the prevalence of ADPKD and the impact of the disease in the Seychelles islands, where approximately 65% of the population is of African descent and 30% of Caucasian or mixed descent. METHODS: Prevalent cases were identified over a 3-year period by requesting all the doctors in the country (most of them are employed within a national health system) to refer all presumed or confirmed cases and by systematically examining the family members of all confirmed cases. The diagnosis was based on standard criteria including ultrasonographic findings and family history. RESULTS: Forty-two cases were identified in this population of 74,331 inhabitants, a total prevalence (per 100,000 total population) of 57 (95% CI, 41-76). All but one of the cases were of Caucasian descent so that the prevalence rates of the disease in the populations of Black and Caucasian descents were respectively 2 (0-11) and 184 (132-249). The prevalence rates of the gene(s) carriers were estimated to be 75 (45-117) in the total population respectively 6 (0-33) and 236 (140-372) in the Black and Caucasian populations. Haplotype analysis in 58 cases from three families showed a common DNA fragment in all affected individuals. Cases had significantly higher blood pressure compared to the general population and 21% had serum creatinine higher than 120 mumol/l. Among the established pedigrees, mean age of death between 1960 and 1995 (haemodialysis was introduced in 1992) was younger in subjects with than those without ADPKD (50.5 vs 67.7 years; P < 0.001). CONCLUSIONS: In the Seychelles, ADPKD clusters in the Caucasian population (possibly a founder effect), is rare in individuals of black descent, and is associated with substantial clinical and survival impact.     

Identification of patients with autosomal dominant polycystic kidney disease at highest risk for end-stage renal disease

To identify those potential factors that, early in the course of disease, mark a population of patients with autosomal dominant polycystic kidney disease (ADPKD) who have worse renal survival, survival analysis and risk ratio calculation for 1215 ADPKD patients were performed. Survival times were calculated as time to dialysis, transplantation, or death. Risk ratios were calculated using the Cox proportional hazards model. Three hundred eighty-eight patients entered end-stage renal disease and 205 patients died. ADPKD2 subjects had longer renal survival than ADPKD1 subjects (median survival, 68 versus 53 yr; P < 0.0005; risk ratio, 2.5). Women had significantly better renal survival than men (56 versus 52 yr; P < 0.0001; risk ratio, 1.6). Subjects who were diagnosed before age 30 and those who developed hypertension before age 35 had worse renal survival than those subjects who were diagnosed after age 30 or those who remained normotensive after age 35, respectively (age of diagnosis: 49 versus 59 yr; P < 0.0001; risk ratio, 3.2; hypertension: 51 versus 65 yr; P < 0.0001; risk ratio, 4.4). Similarly, those who had an episode of gross hematuria before age 30 had a worse renal outcome than those who did not (49 versus 59 yr; P < 0.0001; risk ratio, 2.6). We have also calculated risk ratios for a combined model. When therapeutic interventions become available for this disease, these populations with high risk ratios should be considered for such interventions.     

Germinal and somatic mutations in the PKD2 gene of renal cysts in autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is caused by mutations in one of three genes: PKD1 on chromosome 16 accounts for approximately 85% of cases whereas PKD2 on chromosome 4 accounts for approximately 15%. Mutations in the PKD3 gene are rare. All patients present with similar clinical phenotypes, and the cardinal symptom is the formation of fluid-filled cysts in the kidneys. Previous work has provided data supporting the notion that cysts in ADPKD1 are focal in nature and form after loss of function of polycystin 1. This became evident by demonstrating that the normal PKD1 allele was inactivated somatically by loss of heterozygosity or by mutagenesis in a subset of renal or liver cysts examined. We show in this report, for the first time, multiple novel somatic mutations within the PKD2 gene of epithelial cells, in both kidneys of an ADPKD2 patient. From a total of 21 cysts examined, seven (33%) had the same C insertion within the inherited wild-type allele. In two other cysts, a nonsense mutation and a splice site AG deletion had occurred in a PKD2 allele that could not be identified as the inherited wild-type or mutant. We suggest that the autosomal dominant form of ADPKD2 occurs by a cellular recessive mechanism, supporting a two-hit model for cyst formation.     

Autosomal dominant polycystic kidney disease in a large family

The diagnosis of autosomal dominant polycystic kidney disease (ADPKD) was established in persons (6 adult and 8 children) among 34 members of a three generations family. The presence of coexisting cysts in liver was ascertained in 3 women, and the presence of ovarian cysts was discovered in a 14 years old girl. Arterial hypertension was observed in 2 men and 2 women. The symptoms of initiating renal failure were found in 1 patient. The clinical observation of the most numerous among described in accessible literature family will be continued.     

Immunolocalization of ion transport proteins in human autosomal dominant polycystic kidney epithelial cells

The kidneys of patients with autosomal dominant polycystic kidney disease become massively enlarged due to the progressive expansion of myriad fluid-filled cysts. The epithelial cells that line the cyst walls are responsible for secreting the cyst fluid, but the mechanism through which this secretion occurs is not well established. Recent studies suggest that renal cyst epithelial cells actively secrete Cl across their apical membranes, which in turn drives the transepithelial movement of Na and water. The characteristics of this secretory flux suggest that it is dependent upon the participation of an apical cystic fibrosis transmembrane conductance regulator (CFTR)-like Cl channel and basolateral Na,K-ATPase. To test this hypothesis, we have immunolocalized the CFTR and Na,K-ATPase proteins in intact cysts and in cyst epithelial cells cultured in vitro on permeable filter supports. In both settings, cyst epithelial cells were found to possess Na,K-ATPase exclusively at their basolateral surfaces; apical labeling was not detected. The CFTR protein was present at the apical surfaces of cyst epithelial cells that had been stimulated to secrete through incubation in forskolin. CFTR was detected in intracellular structures in cultured cyst epithelial cells that had not received the forskolin treatment. These results demonstrate that the renal epithelial cells that line cysts in autosomal dominant polycystic kidney disease express transport systems with the appropriate polarity to mediate active Cl and fluid secretion.