Juxtaglomerular apparatus-mediated homeostatic mechanisms: therapeutic implication for chronic kidney disease.

INTRODUCTION: Juxtaglomerular apparatus (JGA)-mediated homeostatic mechanism links to how sodium-glucose cotransporter 2 inhibitors (SGLT2is) slow progression of chronic kidney disease (CKD) and may link to how tolvaptan slows renal function decline in autosomal dominant polycystic kidney disease (ADPKD). AREA COVERED: JGA-mediated homeostatic mechanism has been hypothesized based on investigations of tubuloglomerular feedback and renin-angiotensin system. We reviewed clinical trials of SGLT2is and tolvaptan to assess the relationship between this mechanism and these drugs. EXPERT OPINION: When sodium load to macula densa (MD) increases, MD increases adenosine production, constricting afferent arteriole (Af-art) and protecting glomeruli. Concurrently, MD signaling suppresses renin secretion, increases urinary sodium excretion, and counterbalances reduced sodium filtration. However, when there is marked increase in sodium load per-nephron, as in advanced CKD, MD adenosine production increases, relaxing Af-art and maintaining sodium homeostasis at the expense of glomeruli. The beneficial effects of tolvaptan on renal function in ADPKD may also depend on the JGA-mediated homeostatic mechanisms since tolvaptan inhibits sodium reabsorption in the thick ascending limb.The JGA-mediated homeostatic mechanism regulates Af-arts, constricting to relaxing according to homeostatic needs. Understanding this mechanism may contribute to the development of pharmacotherapeutic compounds and better care for patients with CKD.

Long-Term Outcomes of Longitudinal Efficacy Study With Tolvaptan in ADPKD.

INTRODUCTION: The effects of long-term and uninterrupted tolvaptan treatment on autosomal dominant polycystic kidney disease (ADPKD) are unclear. Therefore, a more than 3-year continuous treatment study was performed. METHODS: From the Kyorin University cohort, 299 patients were surveyed and 179 patients were indicated for tolvaptan having a total kidney volume (TKV) ≥750 ml, TKV slope ≥5%/yr, and estimated glomerular filtration rate (eGFR) ≥15 ml/min per 1.73 m2. Among 179 patients, 118 patients consented to the study. RESULTS: Retrospective pretreatment and prospective on-treatment periods had a median of 1.8 and 4.0 years, respectively. During the 5 treatment-years, the log10(TKV) slope/yr decreased from the pretreatment period (P < 0.0001) and the estimated height-adjusted TKV growth rate α (eHTKV-α, %/yr) decreased from baseline (P < 0.0001). The decline in eGFR improved in female patients (P < 0.0001), but not in males (P = 0.6321). Furthermore, during the 5 treatment-years, eGFR remained significantly better in the group with a percent decrease in eHTKV-α from baseline to the first treatment-year ≥ the median (2.94%) than in the group with a decrease <2.94%. The free-water clearance was higher in males than in females irrespective of treatment. CONCLUSION: The TKV growth rate decreased in 4 years with tolvaptan in both sexes. The insignificant effects of tolvaptan on the eGFR slope in males were likely due to androgen stimulation of cystogenesis and analytical difficulty of longitudinal changes in nonlinear trajectories of eGFR. The larger decrease in eHTKV-α in the first year was related to a better renal prognosis. The vasopressin-mediated water reabsorption was activated more in females than males irrespective of tolvaptan administration.

Genomic analysis of circulating tumor cells in adenosquamous carcinoma of the prostate: a case report.

BACKGROUND: Adenosquamous carcinoma of the prostate (ASCP) is an extremely rare and aggressive prostate cancer variant, whose genomic characteristics have not been elucidated. Although liquid biopsy of circulating tumor cells (CTCs) is an emerging topic in oncology, no study has assessed CTCs in patients with ASCP. CASE PRESENTATION: A 76-year-old man presented with discomfort in his urethra. His prostate-specific antigen (PSA) level was 13.37 ng/mL. A computed tomography (CT) scan indicated a prostate mass with multiple lymph node and lung metastases. The patient underwent transurethral resection of the prostate and prostatic needle biopsy; both specimens demonstrated Gleason grade group 5 acinar adenocarcinoma of the prostate. Bone scintigraphy indicated bone metastasis in the ischium. Combined androgen blockade was implemented, and his serum PSA level rapidly decreased to 0.01 ng/mL. However, a CT scan 6 months after the initial diagnosis revealed worsening of the disease. The patient therefore underwent repeated prostatic needle biopsy; its specimen demonstrated prostatic adenocarcinoma together with squamous carcinoma components. As immunohistochemical analyses showed the tumor cells to be negative for CD56, chromogranin A, synaptophysin, and PSA, the definitive diagnosis was ASCP. Although the patient underwent chemotherapy (docetaxel and cabazitaxel), he died of the disease 3 months after the diagnosis of ASCP, or 13 months after the initial diagnosis of prostatic adenocarcinoma. His PSA values remained ≤ 0.2 ng/mL. CTCs from the patient's blood (collected before starting docetaxel) were analyzed and genomically assessed. It showed 5 cytokeratin (CK)+ CTCs, 14 CK- CTCs, and 8 CTC clusters, per 10 mL. Next-generation sequencing identified a total of 14 mutations in 8 oncogenes or tumor suppressor genes: PIK3CB, APC, CDKN2A, PTEN, BRCA2, RB1, TP53, and CDK12. Of 14 mutations, 9 (64%) were detected on CK- CTCs and 5 (36%) were detected on CK+ CTCs. CONCLUSIONS: This is the first report of CTC analysis and genomic assessment in ASCP. Although the prognosis of ASCP is dismal due to lack of effective treatment, genomic analysis of CTCs might lead to effective treatment options and improved survival.

PKD1-Associated Arachnoid Cysts in Autosomal Dominant Polycystic Kidney Disease.

OBJECTIVES: the prevalence of intracranial aneurysms and arachnoid cysts is higher in patients with autosomal dominant polycystic kidney disease (ADPKD) than in the general population. A genotype correlation was reported for intracranial aneurysms, but it is unclear for arachnoid cysts. Therefore, the genotype correlation with intracranial aneurysms and arachnoid cysts was investigated in ADPKD. MATERIALS AND METHODS: intracranial aneurysms and arachnoid cysts were screened by magnetic resonance imaging (MRI), and PKD genotypes were examined using next-generation sequencing for 169 patients with ADPKD. RESULTS: PKD1-, PKD2- and no-mutation were identified in 137, 24 and 8 patients, respectively. Intracranial aneurysms and arachnoid cysts were found in 34 and 25 patients, respectively, with no significant difference in frequency. Genotype, sex, estimated glomerular filtration rate and age at ADPKD diagnosis significantly affected the age at brain MRI. The proportional hazard risk analyzed using the age at brain MRI adjusted by these four variables was 5.0-times higher in the PKD1 group than in the PKD2 group for arachnoid cysts (P = 0.0357), but it was not different for intracranial aneurysms (P = 0.1605). Arachnoid cysts were diagnosed earlier in the PKD1 group than in the PKD2 group (54.8 vs 67.7 years, P = 0.0231), but no difference was found for intracranial aneurysms (P = 0.4738) by Kaplan-Meier analysis. CONCLUSIONS: this study demonstrated the correlation between arachnoid cysts and PKD1 mutation. The reported association of arachnoid cysts with advanced renal disease may be due to the common correlation of these factors with PKD1 mutation.

Pigmented median raphe cyst of the penis that developed after middle age without infection or trauma history.

INTRODUCTION: Median raphe cysts are rare benign lesions of the male genitalia that can develop anywhere along the midline from meatus to anus. They are believed to be caused by a defect in closure of median raphe during embryonic development. These cysts commonly appear in childhood or adolescence, although some are diagnosed after middle age, typically triggered by infection or trauma. Pigmented median raphe cysts, or those containing melanin pigment and/or melanocytes, are extremely rare. CASE PRESENTATION: A 78-year-old man visited our hospital with a complaint of a penile mass that he first noticed in his 50s which slowly grew, eventually causing voiding difficulty. He had no history of infection or trauma. The lesion was excised, and the pathological diagnosis was pigmented median raphe cyst. CONCLUSION: We successfully treated a rare case of pigmented median raphe cyst of the penis that developed after middle age without infection or trauma history.

Imaging Identification of Rapidly Progressing Autosomal Dominant Polycystic Kidney Disease: Simple Eligibility Criterion for Tolvaptan.

BACKGROUND: Tolvaptan was approved for the treatment of autosomal dominant polycystic kidney disease (ADPKD). However, the official indication of "rapidly progressive disease" is described differently in the clinical guidelines. We aim to define "rapidly progressive disease" by risk of ESRD, which is evaluated using estimated height-adjusted total kidney volume (HtTKV) growth rate. METHODS: The risk of ESRD was retrospectively analyzed in 617 initially non-ESRD adults with ADPKD and observed with standard of care between 2007 and 2018. The estimated annual growth rate of the HtTKV, termed as eHTKV-α (%/year), is derived from the following equation: [HtTKV at age t] = K(1 + eHTKV-α/100)t, where K = 150 mL/m is used in Mayo Imaging Classification and K = 130 mL/m is proposed for individually stable eHTKV-α value from baseline. The accuracy of eHTKV-α to predict ESRD for censored ages was analyzed using time-dependent receiver-operating characteristic curves (ROC). The cutoff point of initially measured eHTKV-α to predict ESRD was assessed using Kaplan-Meier and Cox's proportional hazards models. Performance characteristics of the cutoff point for censored ages were calculated using time-dependent ROC and validated by the bootstrap method. RESULTS: The area under the time-dependent ROC of eHTKV-α to predict ESRD at age 65 was 0.89 ± 0.04 (K = 130). The mean renal survival was less than 70 years at eHTKV-α ≥4.0%/year (K = 130). Mean renal survival was approximately 12 years shorter, and hazard ratio of ESRD was more than 5-time higher at this cutoff point than at lower point. Time-dependent sensitivity for age 65 and cutoff point of 4.0%/year (K = 130) was 93.4 ± 0.3%. Between cutoff points ≥4.0%/year (K = 130) and ≥3.5%/year (K = 150), there was no significant difference in performance characteristics and accuracy to predict ESRD. CONCLUSION: eHTKV-α well predicts ESRD. Initially, measured eHTKV-α ≥4.0%/year (K = 130) defines high-risk ESRD. Without additional conditions, a single eHTKV-α cutoff point identifies subjects that are most likely to benefit from tolvaptan.

Estimation of Changes in Kidney Volume Growth Rate in ADPKD.

INTRODUCTION: In the Mayo Imaging Classification (MIC) for autosomal dominant polycystic kidney disease (ADPKD), the height-adjusted total kidney volume (HtTKV) growth rate is estimated for classification. Estimated HtTKV slope, termed as eHTKV-α, is calculated by the equation [HtTKV at age t] = K(1+α/100)(t-A), where K = 150 and A = 0 are used in MIC. If eHTKV-α is nearly stable during a standard-of-care period, the change in eHTKV-α from baseline can be used for estimation of the treatment effect on the HtTKV slope. METHODS: The constancy of eHTKV-α (A = 0 and K = 150) was evaluated using 453 placebo-assigned subjects in the Tolvaptan Efficacy and Safety in Management of ADPKD and Its Outcomes (TEMPO) 3:4 trial. A and K were sought out respectively by a converged pattern of regression lines of log10(HtTKV) plotted against age for subgroups divided according to MIC, and by change in eHTKV-α from baseline. A total of 239 standard-of-care patients from the Kyorin University Cohort (KUC) served as validation. Changes in eHTKV-α from baseline were evaluated in 809 tolvaptan-treated subjects in TEMPO 3:4. RESULTS: In placebo-assigned subjects, eHTKV-α (A = 0 and K = 150) changed significantly from baseline at the third year. As regression lines of placebo-assigned subgroups converged around age 0, A was set as 0, which was confirmed by KUC. K = 130 was selected because of minimal change in eHTKV-α from baseline. The KUC validated the constancy of eHTKV-α (A = 0 and K = 130) but not that of eHTKV-α (A=0 and K=150). In tolvaptan-treated subjects, eHTKV-α remained significantly lower than baseline for 3 years. CONCLUSIONS: eHTKV-α (A = 0 and K = 130) was nearly stable from baseline through follow-up in standard-of-care adults. Treatment effects on the HtTKV slope can be estimated by changes in eHTKV-α from baseline.

Prognostic significance of the albumin-to-globulin ratio for upper tract urothelial carcinoma.

BACKGROUND: Although the albumin-to-globulin ratio (AGR) is a promising biomarker for various malignancies, few studies have investigated its prognostic significance for upper tract urothelial carcinoma (UTUC). METHODS: This retrospective study conformed to the REporting recommendations for tumour MARKer prognostic studies (REMARK) guideline. We reviewed 179 patients with UTUC who underwent radical nephroureterectomy at our institution between 2008 and 2018. Associations of preoperative clinicopathological factors, including the AGR, with cancer-specific survival (CSS) and overall survival (OS) were assessed. The Cox proportional hazards model was used for univariate and multivariable analyses. AGR was dichotomized as < 1.25 and ≥ 1.25, according to the most discriminatory cutoff determined from the receiver operating characteristic curve analysis. RESULTS: During a median follow-up of 34 months after surgery, 37 patients died from UTUC and 13 died of other causes. The preoperative AGR significantly correlated with pathological T stage, pathological N stage, and adjuvant chemotherapy. Multivariate analyses demonstrated that a decreased (< 1.25) preoperative AGR was an independent poor prognostic factor for both CSS (hazard ratio [HR] = 2.81, P <  0.01) and OS (HR = 2.09, P <  0.05). CONCLUSIONS: Preoperative AGR < 1.25 might serve as a useful prognostic marker for patients with UTUC undergoing radical nephroureterectomy.

Cluster of differentiation 8 and programmed cell death ligand 1 expression in triple-negative breast cancer combined with autosomal dominant polycystic kidney disease and tuberous sclerosis complex: a case report.

BACKGROUND: Autosomal dominant polycystic kidney disease is defined as an inherited disorder characterized by renal cyst formation due to mutations in the PKD1 or PKD2 gene, whereas tuberous sclerosis complex is an autosomal dominant neurocutaneous syndrome caused by mutation or deletion of the TSC2 gene. A TSC2/PKD1 contiguous gene syndrome, which is caused by a chromosomal mutation that disrupts both the TSC2 and PKD1 genes, has been identified in patients with tuberous sclerosis complex and severe early-onset autosomal dominant polycystic kidney disease. The tumor tissue of patients with breast cancer with contiguous gene syndrome has a high mutation burden and produces several neoantigens. A diffuse positive immunohistochemistry staining for cluster of differentiation 8+ in the T cells of breast cancer tissue is consistent with neoantigen production due to high mutation burden. CASE PRESENTATION: A 61-year-old Japanese woman who had been undergoing dialysis for 23 years because of end-stage renal failure secondary to autosomal dominant polycystic kidney disease was diagnosed as having triple-negative breast cancer and underwent mastectomy in 2015. She had a history of epilepsy and skin hamartoma. Her grandmother, mother, two aunts, four cousins, and one brother were also on dialysis for autosomal dominant polycystic kidney disease. Her brother had epilepsy and a brain nodule. Another brother had a syndrome of kidney failure, intellectual disability, and diabetes mellitus, which seemed to be caused by mutation in the CREBBP gene. Immunohistochemistry of our patient's breast tissue showed cluster of differentiation 8 and programmed cell death ligand 1 positivity. CONCLUSIONS: Programmed cell death ligand 1 checkpoint therapy may be effective for recurrence of triple-negative breast cancer in a patient with autosomal dominant polycystic kidney disease and tuberous sclerosis complex.

Plasma copeptin levels predict disease progression and tolvaptan efficacy in autosomal dominant polycystic kidney disease.

In the TEMPO 3:4 Trial, treatment with tolvaptan, a vasopressin V2 receptor antagonist, slowed the increase in total kidney volume and decline in estimated glomerular filtration rate (eGFR) in autosomal dominant polycystic kidney disease (ADPKD). We investigated whether plasma copeptin levels, a marker of plasma vasopressin, are associated with disease progression, and whether pre-treatment copeptin and treatment-induced change in copeptin are associated with tolvaptan treatment efficacy. This post hoc analysis included 1,280 TEMPO 3:4 participants (aged 18-50 years, estimated creatinine clearance ≥60 ml/min and total kidney volume ≥750 mL) who had plasma samples available at baseline for measurement of copeptin using an automated immunofluorescence assay. In placebo-treated subjects, baseline copeptin predicted kidney growth and eGFR decline over 3 years. These associations were independent of sex, age, and baseline eGFR, but were no longer statistically significant after additional adjustment for baseline total kidney volume. In tolvaptan-treated subjects, copeptin increased from baseline to week 3 (6.3 pmol/L versus 21.9 pmol/L, respectively). In tolvaptan-treated subjects with higher baseline copeptin levels, a larger treatment effect was noted with respect to kidney growth rate and eGFR decline. Tolvaptan-treated subjects with a larger percentage increase in copeptin from baseline to week 3 had a better disease outcome, with less kidney growth and eGFR decline after three years. Copeptin holds promise as a biomarker to predict outcome and tolvaptan treatment efficacy in ADPKD.

Age- and height-adjusted total kidney volume growth rate in autosomal dominant polycystic kidney diseases.

BACKGROUND: The Mayo Clinic Image Classification (MIC) was proposed as a renal prognosis prediction model for autosomal dominant polycystic kidney disease (ADPKD). MIC is based on the assumption of exponential constant increase in height-adjusted total kidney volume (HtTKV). HtTKV growth rate is calculated by one-time measurement of HtTKV and age. We named it as an age-adjusted HtTKV growth rate (AHTKV-α). AHTKV-α was compared with HtTKV slope measured by at least two HtTKV values. METHODS: Comparison of repeatability between AHTKV-α and HtTKV slope, correlation of subgroups divided according to baseline AHTKV-α and HtTKV slope with disease manifestations, estimated glomerular filtration rate (eGFR) slope, and renal survival were analyzed in 296 patients with ADPKD. PKD genotype influences were compared between AHTKV-α and HtTKV slope in 88 patients with characterized PKD mutations. RESULTS: Absolute differences between baseline and follow-up measures were significantly larger for the HtTKV slope than for AHTKV-α (P < 0.0001). From baseline AHTKV-α-based subgroups A-E according to MIC, disease manifestations occurred earlier and future eGFR slopes became steeper (P < 0.0001). Multivariate hazard ratios of renal survival differed significantly among baseline AHTKV-α-based subgroups. Inter-subgroup differences in these predictors were less evident during baseline HtTKV slope-based classification. AHTKV-α values, but not HtTKV slopes, were significantly higher for PKD1 mutation carriers than for PKD2 mutation carriers (P < 0.0001). CONCLUSION: MIC is a good renal prediction model applicable to Japanese patients also. AHTKV-α can be a more sensitive and reliable indicator in TKV growth rate than HtTKV slope.

Optimal equation for estimation of glomerular filtration rate in autosomal dominant polycystic kidney disease: influence of tolvaptan.

BACKGROUND: The reliability of various equations for estimating the GFR in ADPKD patients and the influence of tolvaptan on the resulting estimates have not been examined when GFR is calculated on the basis of inulin clearance. METHODS: We obtained baseline and on-tolvaptan measured GFRs (mGFRs), calculated on the basis of inulin clearance, in 114 ADPKD, and these mGFRs were compared with eGFRs calculated according to four basic equations: the MDRD, CKD-EPI, and JSN-CKDI equations and the Cockcroft-Gault formula, as well as the influence of tolvaptan and of inclusion of cystatin C on accuracy of the results. Accuracy of each of the seven total equations was evaluated on the basis of the percentage of eGFR values within mGFR ± 30% (P30). RESULTS: mGFRs were distributed throughout CKD stages 1-5. Regardless of the CKD stage, P30s of the MDRD, CKD-EPI, and JSN-CKDI equations did not differ significantly between baseline values and on-tolvaptan values. In CKD 1-2 patients, P30 of the CKD-EPI equation was 100.0%, whether or not the patient was on-tolvaptan. In CKD 3-5 patients, P30s of the MDRD, CKD-EPI, and JSN-CKDI equations were similar. For all four equations, regression coefficients and intercepts did not differ significantly between baseline and on-tolvaptan values, but accuracy of the Cockcroft-Gault formula was inferior to that of the other three equations. Incorporation of serum cystatin C reduced accuracy. CONCLUSIONS: The CKD-EPI equation is most reliable, regardless of the severity of CKD. Tolvaptain intake has minimal influence and cystatin C incorporation does not improve accuracy.

A potentially crucial role of the PKD1 C-terminal tail in renal prognosis.

BACKGROUND: Autosomal dominant polycystic disease (ADPKD) often results in renal failure. Recently, allelic influences of PKD1 mutation types on renal survival were extensively investigated. Here, we analyzed integrated influences of PKD1 mutation types and positions on renal survival. METHODS: We included 338 (82 pedigrees) and 72 (12 pedigrees) patients with PKD1 and PKD2 mutations, respectively, identified through comprehensive gene analysis of 101 probands with ADPKD. Genetic testing was performed using next-generation sequencing, long-range PCR, and multiplex ligation-dependent probe amplification. Pathogenic mutations were identified by a software package-integrated seven databases and provided access to five cloud-based computing systems. RESULTS: Mean renal survivals of carriers with PKD1 non-truncating-type mutations at positions upstream of G-protein-coupled receptor proteolytic site (GPS-upstream domain), transmembrane domain, or cytoplasmic C-terminal tail (CTT) domain were 70.2, 67.0, and 50.1 years, respectively (P < 0.0001); renal survival was shorter for mutation positions closer to CTT domain, suggesting its crucial role in renal prognosis. Furthermore, in truncating-type mutations, strong inactivation is anticipated on nucleotides downstream from the mutation site, implying CTT domain inactivation irrespective of mutation site. Shorter mean renal survival was found for PKD1 truncating-type than non-truncating-type mutation carriers (P = 0.0348); mean renal survival was not different between PKD1 3'- and 5'-region truncating-type mutation carriers (P = 0.4375), but was shorter in PKD1 3'-region than in 5'-region non-truncating-type mutation carriers (P = 0.0014). Variable strength of CTT domain inactivation might account for these results. CONCLUSIONS: Aforementioned findings indicate that CTT domain's crucial role in renal prognosis needs further investigation by larger studies (ClinicalTrials.gov; NCT02322385).

Distinguishing testicular torsion from torsion of the appendix testis by clinical features and signs in patients with acute scrotum.

PURPOSE: Many physicians encounter confusion and difficulty in distinguishing testicular torsion (TT) from torsion of the appendix testis (TAT) in patients with acute scrotum because of the overlapping signs and symptoms. The objective of our study was to evaluate the clinical features and signs that can help distinguish TT from TAT. PATIENTS AND METHODS: We performed a retrospective study of patients with surgically confirmed TT and TAT at our institute from January 1990 to December 2013. Clinical findings, physical examination findings, climatic conditions, laboratory data, and color Doppler ultrasound (CDUS) findings were compared between the TT and TAT groups. RESULTS: Seventy patients were included in this study (49 with TT and 21 with TAT). Patients with TT were significantly older than those with TAT (p < 0.001). The ambient temperature at onset was significantly lower in patients with TT than in patients with TAT (p = 0.038). Testicular swelling, high-riding testes, onset during sleep, high leukocyte counts, and high creatine phosphokinase levels were significantly more common in patients with TT than with TAT (p = 0.021, 0.032, 0.006, 0.003, and 0.043, respectively). Multivariate analysis showed that age and onset during sleep were significant independent factors for detection of TT. Eight patients (16.3%) underwent preoperative CDUS evaluation, and an absent or decreased blood signal in the involved testes was significantly correlated with the presence of TT (p = 0.018). CONCLUSION: In clinical features, age and onset during sleep might be helpful to distinguish TT from TAT. When supported by findings, urgent surgical exploration is warranted in patients with suspected TT based on symptoms and CDUS features.

Relationship between intracranial aneurysms and the severity of autosomal dominant polycystic kidney disease.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is a hereditary kidney disease characterized by the progressive enlargement of innumerable renal cysts. Although the association of intracranial aneurysms (ICANs) with ADPKD is well known, the relationship between the ICAN and the disease severity including total kidney volume (TKV) and estimated glomerular filtration rate (eGFR) is poorly understood. METHODS: We screened 265 patients with ADPKD (mean age, 48.8 years; range, 14.9-88.3 years) with MR angiography. The patients with a past history related to ICANs were excluded from the study. The incidence and characteristics of ICAN in patients with ADPKD were evaluated. TKV was measured by volumetric analyses of MR imaging. RESULTS: We detected 65 ICANs in 49 patients (37 women and 12 men, mean age, 52.7 years; range, 20.4-86 years). The incidence of ICANs was 18.5% and female patients had was higher incidence (23.1%) than male patients (11.4%) (p = 0.02). An age of those with ICANs was significantly higher than those without (p = 0.006), and the cumulative risk of diagnosis of ICANs increased with age. TKV was significantly larger in those with ICANs than those without (p = 0.001), but eGFR was not different between two groups (p = 0.07). By multivariate analyses, only TKV was significantly related to the development of ICANs (p = 0.02). CONCLUSIONS: The incidence of ICANs increased with age, was higher in females, and correlated with kidney enlargement in patients with ADPKD. Necessity of screening ICANs would be particularly high in elderly women with large kidneys.

Beneficial effect of combined treatment with octreotide and pasireotide in PCK rats, an orthologous model of human autosomal recessive polycystic kidney disease.

Increased intracellular cyclic AMP (cAMP) in renal tubular epithelia accelerates the progression of polycystic kidney disease (PKD). Thus, decreasing cAMP levels by an adenylyl cyclase inhibitory G protein activator is considered to be an effective approach in ameliorating PKD. In fact, pasireotide (PAS) was effective in reducing disease progression in animal models of PKD. However, hyperglycemia caused by the administration of PAS is an adverse effect in its clinical use. Whereas, co-administration of octreotide (OCT) with PAS did not increase serum glucose in normal rats. In the current study, we examined the efficacy of combined treatment with OCT and PAS in PCK rats, an autosomal recessive PKD model. Four-week-old PCK males were treated with the long-acting release type of OCT, PAS, or a combination of both (OCT/PAS) for 12 weeks. After termination, serum and renal tissue were used for analyses. Kidney weight, kidney weight per body weight, renal cyst area, renal Ki67 expression, and serum urea nitrogen were significantly decreased either in the PAS or OCT/PAS group, compared with vehicle. Renal tissue cAMP content was significantly decreased by PAS or OCT/PAS treatment, but not OCT, compared with vehicle. As a marker of cellular mTOR signaling activity, renal phospho-S6 kinase expression was significantly decreased by OCT/PAS treatment compared with vehicle, OCT, or PAS. Serum glucose was significantly increased by PAS administration, whereas no difference was shown between vehicle and OCT/PAS, possibly because serum glucagon was decreased either by the treatment of OCT alone or co-application of OCT/PAS. In conclusion, since serum glucose levels are increased by the use of PAS, its combination with OCT may reduce the risk of hyperglycemia associated with PAS monotherapy against PKD progression.

Tolvaptan suppresses monocyte chemotactic protein-1 excretion in autosomal-dominant polycystic kidney disease.

BACKGROUND: Autosomal-dominant polycystic kidney disease (ADPKD) is characterized by multitudes of expanding renal cysts associated with mononuclear interstitial infiltrates. Monocyte chemotactic protein-1 is produced in the kidneys and excreted in the urine (uMCP1) of these patients in increased amounts. In the TEMPO 3:4 trial, tolvaptan slowed the rate of increase in total kidney volume (TKV) and the rate of decline in estimated glomerular filtration rate (eGFR). In a sub-analysis, we determined whether tolvaptan administration for up to 3 years changed the urinary excretion of MCP-1 referenced to creatinine in 869 treated subjects compared with 438 placebo subjects. METHODS: Treatment group differences of uMCP1 at 0.75, 12, 24 and 36 months were evaluated by ANCOVA with factor of treatment and covariate baseline. RESULTS: At baseline, mean uMCP1 was 429 ± 224 pg/mg in the tolvaptan and 434 ± 233 pg/mg in the placebo groups, ∼4-fold greater than normal. Log uMCP1 associated positively with log TKV ( r = 0.2645, P < 0.0001) and negatively with eGFR ( r = -0.1555 P < 0.0001) and fasting urine osmolality ( r = -0.1933, P < 0.0001). Tolvaptan reduced uMCP1 13.8 ± 4.4% (P < 0.0001) below placebo-treated subjects at 24 months and 14.4 ± 3.7% (P < 0.0001) at 36 months, and to the same extent in females and males. The effect of tolvaptan on uMCP1 excretion at 36 months extended across CKD Stage 1 (11.1 ± 6.4%, P = 0.0595), CKD 2 (13.9 ± 5.4%, P = 0.0050) and CKD 3 (21.4 ± 8.0%, P = 0.0020). CONCLUSION: Tolvaptan, administered for 3 years to patients with ADPKD, caused a sustained reduction in the urinary excretion of MCP-1 relative to placebo.

Polyuria due to vasopressin V2 receptor antagonism is not associated with increased ureter diameter in ADPKD patients.

BACKGROUND: Tolvaptan, a vasopressin V2 receptor antagonist, has been shown to reduce the rates of growth in total kidney volume (TKV) and renal function loss in ADPKD patients, but also leads to polyuria because of its aquaretic effect. Prolonged polyuria can result in ureter dilatation with consequently renal function loss. Therefore, we aimed to investigate the effect of tolvaptan-induced polyuria on ureter diameter in ADPKD patients. METHODS: 70 ADPKD patients were included (51 were randomized to tolvaptan and 19 to placebo). At baseline and after 3 years of treatment renal function was measured (mGFR) and MRI was performed to measure TKV and ureter diameter at the levels of renal pelvis and fifth lumbar vertebral body (L5). RESULTS: In these patients [65.7 % male, age 41 ± 9 years, mGFR 74 ± 27 mL/min/1.73 m2 and TKV 1.92 (1.27-2.67) L], no differences were found between tolvaptan and placebo-treated patients in 24-h urine volume at baseline (2.5 vs. 2.5 L, p = 0.8), nor in ureter diameter at renal pelvis and L5 (4.0 vs. 4.2 mm, p = 0.4 and 3.0 vs. 3.1 mm, p = 0.3). After 3 years of treatment 24-h urine volume was higher in tolvaptan-treated patients when compared to placebo (4.7 vs. 2.3 L, p < 0.001), but no differences were found in ureter diameter between both groups (renal pelvis: 4.2 vs. 4.4 mm, p = 0.4 and L5: 3.1 vs. 3.3 mm, p = 0.4). CONCLUSIONS: Tolvaptan-induced polyuria did not lead to an increase in ureter diameter, suggesting that tolvaptan is a safe therapy from a urological point of view.

Urine Osmolality, Response to Tolvaptan, and Outcome in Autosomal Dominant Polycystic Kidney Disease: Results from the TEMPO 3:4 Trial.

The vasopressin-cAMP-osmolality axis is abnormal in autosomal dominant polycystic kidney disease (ADPKD). In the Tolvaptan Efficacy and Safety in Management of Autosomal Dominant Polycystic Kidney Disease and Its Outcomes 3:4 Trial, a 3-year randomized, placebo-controlled trial in adults, the vasopressin V2 receptor antagonist tolvaptan slowed ADPKD progression in patients with preserved GFR. Here, we investigated the determinants of baseline urine osmolality (Uosm) and its value as a severity marker of ADPKD, the factors influencing the response to tolvaptan, and whether change in Uosm associated with key trial end points. At baseline, lower Uosm independently associated with female sex, presence of hypertension, lower eGFR, higher total kidney volume (TKV), and higher age. Tolvaptan consistently reduced Uosm by 200-300 mOsm/kg over 36 months. The Uosm response to tolvaptan depended on baseline eGFR and Uosm. Subjects with greater change in Uosm experienced a significant reduction in clinical progression events. Among subjects receiving tolvaptan, those with a greater suppression of Uosm had slower renal function decline. Assessment at follow-up, off medication, revealed a significant decrease in Uosm in both placebo and treated groups. Tolvaptan significantly increased plasma osmolality, which returned to baseline at follow-up. In conclusion, baseline Uosm in ADPKD reflects age, renal function, and TKV, and baseline Uosm, eGFR, and TKV influence the effect of tolvaptan on Uosm. The greatest renal benefit occurred in subjects achieving greater suppression of Uosm, that is, those with better eGFR at baseline. These results support the link between vasopressin V2 receptor signaling and ADPKD progression.

Tolvaptan and Kidney Pain in Patients With Autosomal Dominant Polycystic Kidney Disease: Secondary Analysis From a Randomized Controlled Trial.

BACKGROUND: Kidney pain is a common complication in patients with autosomal dominant polycystic kidney disease (ADPKD), and data from the TEMPO 3:4 trial suggested that tolvaptan, a vasopressin V2 receptor antagonist, may have a positive effect on kidney pain in this patient group. Because pain is difficult to measure, the incidence of kidney pain leading to objective medical interventions was used in the present study to assess pain. STUDY DESIGN: Secondary analysis from a randomized controlled trial. SETTING & PARTICIPANTS: Patients with ADPKD with preserved kidney function. INTERVENTION: Tolvaptan or placebo. OUTCOMES: Kidney pain events defined by objective medical interventions. MEASUREMENTS: Kidney pain events were recorded and independently adjudicated. Incidence of a first kidney pain event was assessed overall and categorized into 5 subgroups according to severity. RESULTS: Of 1,445 participating patients (48.4% women; mean age, 39±7 [SD] years; mean estimated glomerular filtration rate, 81±22mL/min/1.73m2; median total kidney volume, 1,692 [IQR, 750-7,555] mL), 50.9% reported a history of kidney pain at baseline. History of urinary tract infections, kidney stones, or hematuria (all P<0.001) and female sex (P<0.001) were significantly associated with history of kidney pain. Tolvaptan use resulted in a significantly lower incidence of kidney pain events when compared to placebo: 10.1% versus 16.8% (P<0.001), with a risk reduction of 36% (HR, 0.64; 95% CI, 0.48-0.86). The reduction in pain event incidence by tolvaptan was found in all groups irrespective of pain severity and was independent of predisposing factors (P for interaction > 0.05). The effect of tolvaptan was explained at least in part by a decrease in incidence of urinary tract infections, kidney stones, and hematuria when compared to placebo. LIMITATIONS: Trial has specific inclusion criteria for total kidney volume and kidney function. CONCLUSIONS: Tolvaptan decreased the incidence of kidney pain events independent of patient characteristics predisposing for kidney pain and possibly in part due to reductions in ADPKD-related complications.