Incidence and survival of end-stage kidney disease due to polycystic kidney disease in Australia and New Zealand (1963-2014)

Autosomal dominant polycystic kidney disease (ADPKD) with multiple complications: Management challenges

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary polycystic kidney disease characterized by renal enlargement, resulting in renal failure. In Indonesia, the exact prevalence of ADPKD is unknown due to limited reports on the disease. The aim of this study was to report a case of a patient with ADPKD with multiple complications. A 54-year-old male presented to the emergency room of Dr. Soetomo Academic General Hospital, Surabaya, Indonesia, with a chief complaint of dark-red-colored urine for one week. There was a progressive abdominal enlargement over the past five years, which had become more tense and rigid for the past one month. The patient had a history of fatigue and hypertension with routine follow-up. Physical examination on admission showed normal vital signs, and the abdominal assessment revealed a palpable hard mass approximately 4 cm in size in the right upper abdomen. Laboratory test indicated anemia, leukocytosis, lymphopenia, proteinuria, hematuria, leukocyturia, and elevated serum creatinine and urea levels. Abdominal imaging using ultrasonography, computed tomography (CT) scan, and magnetic resonance imaging (MRI) revealed bilateral kidney and liver enlargement containing multiple cysts, suggesting polycystic kidney and liver disease. There was a ruptured cyst in the middle of the left kidney pole with minimal ascites found in the CT scan. The MRI exhibited the presence of multiple cysts in both kidneys, partially filled with blood. The patient was diagnosed with ADPKD, gross hematuria, acute or chronic kidney disease (CKD), urinary tract infection (UTI), normochromic-normocytic anemia, and metabolic acidosis. Dietary control with high-calorie, high-protein, and low-salt diet; fluid balance; and other symptomatic medications were initiated. It is critical to be aware of risk factors associated with the rapid progression of ADPKD in order to be able to provide a favorable impact on the disease prevention and management.

Exploring the impact and utility of genomic sequencing in established CKD

Clinical genetics is increasingly recognized as an important area within nephrology care. Clinicians require awareness of genetic kidney disease to recognize clinical phenotypes, consider use of genomics to aid diagnosis, and inform treatment decisions. Understanding the broad spectrum of clinical phenotypes and principles of genomic sequencing is becoming increasingly required in clinical nephrology, with nephrologists requiring education and support to achieve meaningful patient outcomes. Establishment of effective clinical resources, multi-disciplinary teams and education is important to increase application of genomics in clinical care, for the benefit of patients and their families. Novel applications of genomics in chronic kidney disease include pharmacogenomics and clinical translation of polygenic risk scores. This review explores established and emerging impacts and utility of genomics in kidney disease.

Long-Term Effects of Tolvaptan in Autosomal Dominant Polycystic Kidney Disease: Predictors of Treatment Response and Safety over 6 Years of Continuous Therapy

Tolvaptan, an oral vasopressin V2 receptor antagonist, reduces renal volume expansion and loss of renal function in patients with autosomal dominant polycystic kidney disease (ADPKD). Data for predictive factors indicating patients more likely to benefit from long-term tolvaptan are lacking. Data were retrospectively collected from 55 patients on tolvaptan for 6 years. Changes in renal function, progression of renal dysfunction (estimated glomerular filtration rate [eGFR], 1-year change in eGFR [ΔeGFR/year]), and renal volume (total kidney volume [TKV], percentage 1-year change in TKV [ΔTKV%/year]) were evaluated at 3-years pre-tolvaptan, at baseline, and at 6 years. In 76.4% of patients, ΔeGFR/year improved at 6 years. The average 6-year ΔeGFR/year (range) minus baseline ΔeGFR/year: 3.024 (-8.77-20.58 mL/min/1.73 m2). The increase in TKV was reduced for the first 3 years. A higher BMI was associated with less of an improvement in ΔeGFR (p = 0.027), and family history was associated with more of an improvement in ΔeGFR (p = 0.044). Hypernatremia was generally mild; 3 patients had moderate-to-severe hyponatremia due to prolonged, excessive water intake in response to water diuresis-a side effect of tolvaptan. Family history of ADPKD and baseline BMI were contributing factors for ΔeGFR/year improvement on tolvaptan. Hyponatremia should be monitored with long-term tolvaptan administration.

Prevalence of Renal Neoplasia in Autosomal Dominant Polycystic Kidney Disease: Systematic Review and Meta-Analysis

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is a common inherited condition; however, its relationship with renal cell carcinoma (RCC) remains unclear. This paper aims to establish the prevalence of RCC and its subtypes amongst ADPKD patients.

METHODS

A database search was conducted to retrieve studies reporting RCC occurrence within ADPKD patients until July 2023. Key outcomes included number and subtype of RCC cases, and number of RCCs presenting incidentally. A random-effects meta-analysis was performed.

RESULTS

Our search yielded 569 articles, 16 met the inclusion criteria. Nephrectomy specimens from 1,147 ADPKD patients were identified. Of studies reporting per-kidney results (n = 13), 73 RCCs were detected amongst 1,493 kidneys, equating to a per-kidney prevalence of 4.3% (95% CI, 3.1-5.7, I2 = 15.7%). 75 ADPKD patients were found to have RCC (75/1,147), resulting in a per-person prevalence of 5.7% (95% CI, 3.7-7.9, I2 = 40.3%) (n = 16). As 7 patients had bilateral disease, 82 RCCs were detected in total. Of these, 39 were clear cell RCC, 35 were papillary and 8 were other. As such, papillary RCCs made up 41.1% (95% CI, 25.9-56.9, I2 = 18.1%) of detected cancers. The majority of RCCs were detected incidentally (72.5% [95% CI, 43.7-95.1, I2 = 66.9%]).

CONCLUSION

ADPKD appears to be associated with the papillary RCC subtype. The clinical implications of these findings are unclear, however, may become apparent as outcomes and life expectancy amongst APDKD patients improve.

Thiamet G as a Potential Treatment for Polycystic Kidney Disease

BACKGROUND/AIM

Autosomal dominant polycystic kidney disease (ADPKD) is a prevalent genetic disorder primarily caused by mutations in Pkd1 (PC1), which account for the majority of ADPKD cases. These mutations contribute to the formation of cysts in the kidneys and other organs, ultimately leading to renal failure. Unfortunately, there are currently no available preventive treatments for this disease.

MATERIALS AND METHODS

In this study, we utilized Pkd1-knockdown mice and cells to investigate the potential involvement of O-GlcNAcylation in the progression of PKD. Additionally, we examined the effects of thiamet G, an inhibitor of O-GlcNAcase (OGA), on PKD mice.

RESULTS

Our findings indicate that both O-GlcNAcylation and OGT (O-GlcNAc transferase) were downregulated in the renal tissues of Pkd1-silenced mice. Furthermore, O-GlcNAcylation was shown to regulate the stability and function of the C-terminal cytoplasmic tail (CTT) of PC1. Treatment of PKD mice with thiamet G resulted in a reduction of renal cytogenesis in these animals.

CONCLUSION

These results highlight the unique role of O-GlcNAcylation in the development of cyst formation in PKD and propose it as a potential therapeutic target for the treatment of PKD.

Long-Term Outcomes of Transcatheter Aortic Valve Replacement in Patients With End-Stage Renal Disease

Background

Aortic stenosis is prevalent in end‐stage renal disease. Transcatheter aortic valve replacement (TAVR) is a plausible alternative for surgical aortic valve replacement. However, little is known regarding long‐term outcomes in patients with end‐stage renal disease who undergo TAVR.

Methods and Results

We identified all patients with end‐stage renal disease who underwent TAVR from 2011 through 2016 using the United States Renal Data System. The primary end point was 5‐year mortality after TAVR. Factors associated with 1‐ and 5‐year mortality were analyzed. A total of 3883 TAVRs were performed for patients with end‐stage renal disease. Mortality was 5.8%, 43.7%, and 88.8% at 30 days, 1 year, and 5 years, respectively. Case volumes increased rapidly from 17 in 2011 to 1495 in 2016. Thirty‐day mortality demonstrated a dramatic reduction from 11.1% in 2012 to 2.5% in 2016 (P=0.01). Age 75 or older (hazard ratio [HR], 1.14; 95% CI, 1.05–1.23 [P=0.002]), body mass index <25 (HR, 1.18; 95% CI, 1.08–1.28 [P<0.001]), chronic obstructive pulmonary disease (HR, 1.25; 95% CI, 1.1–1.35 [P<0.001]), diabetes mellitus as the cause of dialysis (HR, 1.22; 95% CI, 1.11–1.35 [P<0.001]), hypertension as the cause of dialysis (HR, 1.17; 95% CI, 1.06–1.29 [P=0.004]), and White race (HR, 1.17; 95% CI, 1.06–1.3 [P=0.002]) were independently associated with 5‐year mortality.

Conclusions

Short‐term outcomes of TAVR in patients with end‐stage renal disease have improved significantly. However, long‐term mortality of patients on dialysis remains high.

Up-Regulation of DNA Damage Response Signaling in Autosomal Dominant Polycystic Kidney Disease

DNA damage and alterations in DNA damage response (DDR) signaling could be one of the molecular mechanisms mediating focal kidney cyst formation in autosomal dominant polycystic kidney disease (ADPKD). The aim of this study was to test the hypothesis that markers of DNA damage and DDR signaling are increased in human and experimental ADPKD. In the human ADPKD transcriptome, the number of up-regulated DDR-related genes was increased by 16.6-fold compared with that in normal kidney, and by 2.5-fold in cystic compared with that in minimally cystic tissue (P < 0.0001). In end-stage human ADPKD tissue, γ-H2A histone family member X (H2AX), phosphorylated ataxia telangiectasia and radiation-sensitive mutant 3 (Rad3)-related (pATR), and phosphorylated ataxia telangiectasia mutated (pATM) localized to cystic kidney epithelial cells. In vitro, pATR and pATM were also constitutively increased in human ADPKD tubular cells (WT 9-7 and 9-12) compared with control (HK-2). In addition, extrinsic oxidative DNA damage by hydrogen peroxide augmented γ-H2AX and cell survival in human ADPKD cells, and exacerbated cyst growth in the three-dimensional Madin-Darby canine kidney cyst model. In contrast, DDR-related gene expression was only transiently increased on postnatal day 0 in Pkd1^RC/RC mice, and not altered at later time points up to 12 months of age. In conclusion, DDR signaling is dysregulated in human ADPKD and during the early phases of murine ADPKD. The constitutive expression of the DDR pathway in ADPKD may promote survival of PKD1-mutated cells and contribute to kidney cyst growth.

A novel monogenic preimplantation genetic testing strategy for sporadic polycystic kidney caused by de novo PKD1 mutation

Autosomal dominant hereditary polycystic kidney disease (ADPKD) is the most common inherited kidney disease that causes end-stage renal disease and kidney failure. Preimplantation genetic testing for monogenic (PGT-M) can effectively prevent the transmission of genetic diseases from parents to the offspring before pregnancy. However, PGT-M currently adopts the single nucleotide polymorphism (SNP) linkage analysis for embryo's pathogenic gene carrying status and linkage analysis requires proband of the family. Here we report a new PGT-M strategy using single sperm SNP linkage analysis for male patient with sporadic ADPKD caused by de novo PKD1 mutation. We recruited five couples with male patient with ADPKD caused by de novo PKD1 mutation, and 39 embryos from six PGT-M cycles were detected. The five couples had at least one embryo that does not carry the PKD1 mutation. Within these five couples, the accuracy of carrier status of embryos was confirmed by amniotic fluid gene detection of two couples and two couples successfully delivered healthy fetuses. Therefore, the new PGT-M strategy of using single sperm SNP linkage analysis was proved to be feasible and effective for male patient with ADPKD caused by de novo PKD1 mutation.

Management of Autosomal Dominant Polycystic Kidney Disease (ADPKD) During Pregnancy: Risks and Challenges

Autosomal dominant polycystic kidney disease (ADPKD) affects up to 1 in 1000 people. The disease is characterized by the progressive development of cysts throughout the renal parenchyma due to inherited pathogenic variants in genes including PKD1 or PKD2 and eventually leads to gradual loss of renal function, along with manifestations in other organ systems such as hepatic cysts and intracranial aneurysms. ADPKD management has advanced considerably in recent years due to genetic testing availability, pre-implantation genetic diagnosis technology and new therapeutic agents. Renal disease in pregnancy is recognised as an important risk factor for adverse maternal and fetal outcome. Women with ADPKD and health professionals face multiple challenges in optimising outcomes during the pre-pregnancy, pregnancy and post-partum periods.

Urinary T cells correlate with rate of renal function loss in autosomal dominant polycystic kidney disease

Several innate immune response components were recognized as outcome predictors in autosomal dominant polycystic kidney disease (ADPKD) and their causative role in disease pathogenesis was confirmed in animal models. In contrast, the role of adaptive immunity in ADPKD remains relatively unexplored. Therefore, we evaluated T cell populations in kidney and urine of ADPKD patients using flow cytometry and confocal immunofluorescence microscopy approaches. These analyses revealed ADPKD-associated overall increases in the number of intrarenal CD4 and CD8 T cells that were associated with a loss of polarity in distribution between the cortex and medulla (higher in medulla vs. cortex in controls). Also, the urinary T cell-based index correlated moderately with renal function decline in a small cohort of ADPKD patients. Together, these data suggest that similar to innate immune responses, T cells participate in ADPKD pathogenesis. They also point to urinary T cells as a novel candidate marker of the disease activity in ADPKD.

End-Stage Kidney Failure in Oman: An Analysis of Registry Data with an Emphasis on Congenital and Inherited Renal Diseases

Globally, end-stage kidney disease (ESKD) is a huge burden on health care systems. The aims of this study were to perform a comprehensive epidemiological and etiological report of ESKD patients commencing RRT in Oman with an emphasis on genetic causes and inherited kidney disease. All newly registered Omani patients with ESKD commencing RRT from 2001 until 2015 (n = 2,922) were analysed using the RRT register in Oman. All potentially genetic or inherited causes of ESKD were reviewed. In Oman, ESKD is more prevalent in males (57.1%) than females (42.9%) with a median age of incident ESKD of 53 years. Diabetic nephropathy was the most prevalent cause of ESKD (46%), followed by hypertensive nephropathy (19%), glomerulonephritis (15%), and inherited kidney disease (5%). For patients less than 20 years of age inherited kidney disease accounted for 32.5% of cases. Of this cohort with inherited renal disease, 40.3% had autosomal dominant polycystic kidney disease, 11.5% had congenital anomalies of the kidney and urinary tract, 9.4% had Alport syndrome, and 7.2% had autosomal recessive polycystic kidney disease. This study represents a comprehensive population-based epidemiological and etiological report of ESKD patients in Oman commencing RRT. Inherited kidney disease was the leading cause of paediatric ESKD.