Fifteen-year follow-up of acquired renal cystic disease - a gender difference

Long-term natural history of acquired cystic disease of the kidney

Patients with acquired cystic disease of the kidney (ACDK) were followed longitudinally over an average of 21.7 +/- 5.4 years to determine the natural history of the disease; that is, how big the kidneys become, when the kidney size reaches a plateau, and when the size regresses. Twenty-seven male and 20 female patients with chronic glomerulonephritis treated at our hospital were investigated. CT scans were performed once a year and kidney volume was measured. Two different quadratic curves with a node of 5.2 years for males and 2.5 years for females after the start of hemodialysis were fitted to log-transformed kidney volume to the duration of hemodialysis using a linear mixed model. The maximum kidney volume in male patients was obtained 21.1 years after the start of hemodialysis using this model. Peak values of kidney volume were demonstrated in 19 of 26 cases during the observation period. The median peak value (interquartile range) of bilateral kidney volumes was 274 (165-849) mL/1.73 m(2) occurring 19.1 +/- 4.5 years after the start of dialysis. In one male patient who had undergone nephrectomy due to renal cell carcinoma and in two of the remaining 26 male patients, the maximum kidney volume of 782 (residual kidney), 1151, and 1129 mL regressed to 428, 616, and 847 mL (reduction rate: 45.3, 46.5, and 25.0%) at 20.6, 25.4, and 23.1 years after the start of hemodialysis, respectively. Kidney enlargement due to ACDK reached a plateau after 21.1 years of hemodialysis in the male patients. Partial regression of severe ACDK may occur naturally after long-term hemodialysis without renal transplantation.

Gender differences in mRNA expression of ATP-binding cassette efflux and bile acid transporters in kidney, liver, and intestine of 5/6 nephrectomized rats

ATP-binding cassette (ABC) transporters including multidrug resistance proteins (Mdr), multidrug resistance-associated proteins (Mrp), and breast cancer resistance protein (Bcrp/Abcg2) play major roles in tissue defense. Abcg5/g8 is essential in cholesterol efflux. The present study was aimed at elucidating alteration in expression of these transporters and bile-acid transporters during chronic kidney disease (CKD) and underlying molecular mechanisms. Seven weeks after 5/6 nephrectomy (Nx), mRNA expression of 16 aforementioned transporters in kidney, liver, jejunum, and large intestine of male and female Nx rats was quantified with the branched DNA signal amplification assay. In Nx males, intestinal expression of all the transporters remained unchanged; hepatic expression of most transporters was not altered, except increases in Mdr1a, Mrp3, and Abcg8. In male remnant kidneys, kidney-predominant transporter Abcg2 decreased and correlated with CKD severity, whereas Mdr1b, Mrp3, and ileal bile-acid transporter increased and correlated with CKD severity. Such changes were largely absent in Nx females. Renal alterations of these transporters correlated with increases of cytokines and/or decreases of nuclear receptors such as estrogen receptor alpha and glucocorticoid receptor. Renal protein expression of Mrp2 increased, whereas that of Mrp4 remained unchanged in both genders of Nx rats. Treatment of rat proximal tubule NRK-52E cells with interleukin (IL)-1beta and IL-6 increased Mrp3 mRNA expression. In conclusion, during CKD, renal expression of many ABC transporters was altered at the transcriptional level, whereas hepatic mRNA expression of most ABC transporters remained unchanged. Down-regulation of steroid hormone receptors and increase of inflammatory cytokines may contribute to alteration of transporter gene expression in kidney during CKD.

Renal Cell Carcinoma in Transplant Recipients with Acquired Cystic Kidney Disease

BACKGROUND

Acquired cystic kidney disease (ACKD) is a widely known renal cell carcinoma risk factor.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

An ultrasound screening of the native kidneys in all renal transplant patients of a renal outpatient clinic who received a transplant between 1970 and 1998 and presented between 1997 and 2003 (n = 916) was initiated prospectively. A total of 561 patients were screened.

RESULTS

A total of 129 (23%) patients had ACKD; 46 (8.2%) patients had complex renal cysts (Bosniak classification, category IIF to III); and eight (1.5%) patients had newly diagnosed renal cell carcinoma, seven of which were associated with ACKD (category IV). One patient had renal cell carcinoma in the transplanted kidney. Together with 19 patients of the cohort with formerly diagnosed renal cell carcinoma (18 of them associated with ACKD), the prevalence of renal cell carcinoma among all patients was 4.8%; among the patients with ACKD, it was 19.4% (without ACKD 0.5%; P = 0.0001); and among the patients with complex renal cysts (category IIF to III), it was 54.4%. The patients with ACKD were older (54 +/- 13 versus 51 +/- 14 yr; P = 0.048), more often male (65 versus 54%; P = 0.03), more often had heart disease (44 versus 29%; P = 0.001), had larger kidneys (6.9 and 6.8 cm versus 6.0 and 5.9 cm; P < 0.001), and had more calcifications (29 versus 15%; P = 0.002). Renal cell carcinoma was bilateral in 26% of cases. Tumor histology was clear cell carcinoma in 58% and papillary carcinoma in 42% of cases; one patient had both. Only one patient had a lung metastasis, and no patient died.

CONCLUSIONS

Renal cell carcinoma occurs often after renal transplantation and that especially patients with ACKD should routinely be screened. Because ACKD after renal transplantation seems to be less frequent (23%) than during dialysis treatment (30 to 90%), renal transplantation may inhibit renal cell carcinoma.

Gender differences in renal nuclear receptors and aryl hydrocarbon receptor in 5/6 nephrectomized rats

This study was aimed at delineating molecular pathways essential in gender-different pathogenesis of chronic kidney diseases (CKD). Renal transcripts of nuclear receptors and metabolic enzymes in male and female kidneys from 5/6 nephrectomized (Nx) rats 7 weeks post-Nx were examined using branched DNA signal amplification assay. Nx-males had marked kidney injury coupled with anemia and malnutrition. Nx-females had moderate renal injury, and were free of albuminuria, anemia, and malnutrition. Nx-males had systemic and renal inflammation, which were largely absent in Nx-females. Blood 17beta-estradiol, testosterone, and corticosterone did not change, whereas urinary testosterone decreased in both genders. Compared to males, female kidneys had higher androgen receptor (AR) and aryl hydrocarbon receptor (AhR) but lower estrogen receptor alpha (ERalpha). Compared to Nx-males, female remnant kidneys had less decreases in ERalpha and peroxisome proliferator-activated receptor alpha (PPARalpha), had no induction of AR and decrease of acyl-CoA oxidase, whereas had induction of cytochrome P450 4a1 (Cyp4a1) but decrease of AhR. Renal protein expression of a 52-kDa isoform of Wilm's tumor 1 (WT1), transcription factor critical in nephrogenesis, decreased dramatically in Nx-males but largely preserved in Nx-females. In conclusion, gender divergences in basal expression and alteration of ERalpha, AR, AhR, WT1, and PPARalpha/Cyp4a1 during CKD may explain gender differences in CKD progression and outcome of renal transplantation.

Renal cell carcinoma and end stage renal disease

PURPOSE

Patients with ESRD secondary to acquired renal cystic disease have been reported to have a higher incidence of RCC than the general population. We examined the clinical and pathological significance of incidental renal masses in patients with ESRD.

MATERIALS AND METHODS

From January 1994 to July 2000, 852 consecutive patients with ESRD who were being considered for renal transplantation at University of Mississippi Medical Center were evaluated with renal ultrasound as part of assessment for possible kidney transplantation. Those patients with ultrasound suspicious for a malignant renal lesion were further evaluated with CT of the abdomen with and without intravenous contrast medium. Any patient with CT findings suspicious for RCC was recommended to undergo radical nephrectomy before kidney transplantation.

RESULTS

A total of 19 patients had CT criteria for a possible malignant renal lesion. Seven patients had Bosniak class 3 renal cysts and 12 patients had solid, enhancing renal masses. Of the patients 17 underwent radical nephrectomy. On pathological examination 14 patients had RCC with a 1.64% prevalence in the population screened. Mean Fuhrman nuclear grade in our patients was 2.45.

CONCLUSIONS

RCC in patients with ESRD are of clinical significance, considering the size, grade, histology and pathological stage of these tumors. The higher prevalence of clinically significant RCC in patients with ESRD as well as the risk of cancer progression while patients are on immunosuppressive medications justifies screening for RCC in patients with ESRD who are awaiting renal transplantation.

Renal cell and transitional cell carcinoma in a Japanese population undergoing maintenance dialysis

PURPOSE

We verified differences in the incidence, clinical characteristics and outcomes between patients on chronic dialysis for end stage renal disease with renal cell carcinoma (RCC) and those with transitional cell carcinoma (TCC).

MATERIALS AND METHODS

Data regarding RCC and TCC were reviewed in the medical records of 6,201 patients with end stage renal disease who underwent chronic dialysis between January 1990 and June 2003 in our 38 affiliated dialysis centers, and data were compared with those reported in Australia and New Zealand.

RESULTS

Among the patients RCC developed in 38 (0.61%) and TCC developed in 16 (0.26%) during maintenance dialysis. The primary renal disease was chronic glomerulonephritis in patients with RCC (68.4%) and diabetic nephropathy in patients with TCC (43.8%, p = 0.002). Mean patient age at initiation of dialysis was 45 years for those with RCC and 63 for those with TCC (p < 0.001). Mean interval from dialysis induction to tumor diagnosis was 143 months for patients with RCC and 54 months for patients with TCC (p < 0.001). Of 38 RCCs 23 (60.5%) were incidentally detected by regular abdominal imaging examinations while painless gross hematuria was the cardinal symptom in 13 (81.2%) of 16 TCCs. Overall and cancer specific survivals after tumor diagnosis were significantly superior in patients with RCC compared to those with TCC (p = 0.0001 and p = 0.0003, respectively), and the cancer specific 5-year survival was 88.9% for RCC and 29.5% for TCC. In both cancers tumor stage significantly increased the risk of cancer specific death. Compared with patients from Australia and New Zealand, the incidence of RCC was higher and that of TCC was lower in our patients (p <0.001).

CONCLUSIONS

In the Japanese population on dialysis RCC is more common than TCC. Since long-term dialysis is a risk factor for RCC, regular imaging examinations may have contributed to the favorable outcome of our patients on dialysis with RCC. In contrast, the unfavorable outcome of TCC suggests the need for effective diagnostic measures for early detection of TCC in patients on dialysis.

Cancers of the kidney and urinary tract in patients on dialysis for end-stage renal disease: analysis of data from the United States, Europe, and Australia and New Zealand

Patients on maintenance dialysis have increased risk for cancer, especially in the kidney and urinary tract. In a retrospective cohort of 831,804 patients starting dialysis during 1980 to 1994 in the United States, Europe, or Australia and New Zealand, standardized incidence ratios (SIR) with 95% confidence intervals (CI) were calculated for kidney and bladder cancers. Risks for cancers of the kidney (SIR 3.6; CI 3.5 to 3.8) and bladder (SIR 1.5; CI 1.4 to 1.6) were increased, relatively more in younger than older patients and more in female patients (kidney: SIR 4.6, CI 4.3 to 4.9; bladder: SIR 2.7, CI 2.4 to 2.9) than male patients (kidney: SIR 3.2, CI 3.0 to 3.4; bladder: SIR 1.3, CI 1.2 to 1.3). SIR for kidney cancer were raised in all categories of primary renal disease, and for bladder cancer in all but diabetes and familial, hereditary diseases. Notably high SIR occurred in toxic nephropathies (chiefly analgesic nephropathy) and miscellaneous conditions (a category that includes Balkan nephropathy), the excess of kidney cancer in these conditions being urothelial in origin. SIR for kidney cancer rose significantly, and those for bladder cancer fell (not reaching significance) with time on dialysis. There was no association with type of dialysis. The pattern of increased risk for renal parenchymal cancer in dialysis patients is consistent with causation through acquired renal cystic disease and of urothelial cancers of the kidney and bladder with the carcinogenic effects of certain primary renal diseases.