Global analysis of urinary extracellular vesicle small RNAs in autosomal dominant polycystic kidney disease.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is the most prevalent monogenic renal disease progressing to end-stage renal disease. There is a pressing need for the identification of early ADPKD biomarkers to enable timely intervention and the development of effective therapeutic approaches. Here, we profiled human urinary extracellular vesicles small RNAs by small RNA sequencing in patients with ADPKD and compared their differential expression considering healthy control individuals to identify dysregulated small RNAs and analyze downstream interaction to gain insight about molecular pathophysiology. METHODS: This is a cross-sectional study where urine samples were collected from a total of 23 PKD1-ADPKD patients and 28 healthy individuals. Urinary extracellular vesicles were purified, and small RNA was isolated and sequenced. Differentially expressed Small RNA were identified and functional enrichment analysis of the critical miRNAs was performed to identify driver genes and affected pathways. RESULTS: miR-320b, miR-320c, miR-146a-5p, miR-199b-3p, miR-671-5p, miR-1246, miR-8485, miR-3656, has_piR_020497, has_piR_020496 and has_piR_016271 were significantly upregulated in ADPKD patient urine extracellular vesicles and miRNA-29c was significantly downregulated. Five 'driver' target genes (FBRS, EDC3, FMNL3, CTNNBIP1 and KMT2A) were identified. CONCLUSIONS: The findings of the present study make significant contributions to the understanding of ADPKD pathogenesis and to the identification of novel biomarkers and potential drug targets aimed at slowing disease progression in ADPKD.

PKD1 Truncating Mutations Accelerate eGFR Decline in Autosomal Dominant Polycystic Kidney Disease Patients.

INTRODUCTION: Autosomal dominant polycystic kidney disease (ADPKD) is a monogenic disease characterized by the accumulation of fluid-filled cysts in the kidneys, leading to renal volume enlargement and progressive kidney function impairment. Disease severity, though, may vary due to allelic and genetic heterogeneity. This study aimed to determine genotype-phenotype correlations between PKD1 truncating and non-truncating mutations and kidney function decline in ADPKD patients. METHODS: We established a single-center retrospective cohort study in Kuwait where we followed every patient with a confirmed PKD1-ADPKD diagnosis clinically and genetically. Renal function tests were performed annually. We fitted generalized additive mixed effects models with random intercepts for each individual to analyze repeated measures of kidney function across mutation type. We then calculated survival time to kidney failure in a cox proportional hazards model. Models were adjusted for sex, age at visit, and birth year. RESULTS: The study included 22 truncating and 20 non-truncating (42 total) patients followed for an average of 6.6 years (range: 1-12 years). Those with PKD1 truncating mutations had a more rapid rate of eGFR decline (-4.7 mL/min/1.73 m2 per year; 95% CI: -5.0, -4.4) compared to patients with PKD1 non-truncating mutations (-3.5 mL/min/1.73 m2 per year; 95% CI: -4.0, -3.1) (p for interaction <0.001). Kaplan-Meier survival analysis of time to kidney failure showed that patients with PKD1 truncating mutations had a shorter renal survival time (median 51 years) compared to those with non-truncating mutations (median 56 years) (P for log-rank = 0.008). CONCLUSION: In longitudinal and survival analyses, patients with PKD1 truncating mutations showed a faster decline in kidney function compared to patients PKD1 non-truncating mutations. Early identification of patients with PKD1 truncating mutations can, at best, inform early clinical interventions or, at least, help suggest aggressive monitoring.

Association of significantly elevated plasma levels of NGAL and IGFBP4 in patients with diabetic nephropathy.

BACKGROUND: Diabetic nephropathy (DN) is a type of progressive kidney disease affecting approximately 40% of patients with diabetes. Current DN diagnostic criteria predominantly rely on albuminuria and serum creatinine (sCr) levels. However, the specificity and reliability of both markers are limited. Hence, reliable biomarkers are required for early diagnosis to effectively manage DN progression. METHODS: In this study, a cohort of 159 individuals were clinically evaluated and the plasma levels of NGAL, IGFBP-1, IGFBP-3, and IGFBP-4 were determined using Multiplexing Assays. Additionally, the association between the plasma levels of NGAL, IGFBP-1, IGFBP-3, and IGFBP-4 in patients with DN were compared to those in patients with T2D without kidney disease and control participants. RESULTS: Circulating level of NGAL were significantly higher in people with DN compared to people with T2D and non-diabetic groups (92.76 ± 7.5, 57.22 ± 8.7, and 52.47 ± 2.9 mg/L, respectively; p <  0.0001). IGFBP-4 showed a similar pattern, where it was highest in people with DN (795.61 ng/ml ±130.7) compared to T2D and non-diabetic people (374.56 ng/ml ±86.8, 273.06 ng/ml ±27.8 respectively, ANOVA p <  0.01). The data from this study shows a significant positive correlation between NGAL and IGFBP-4 in people with DN (ρ = .620, p <  0.005). IGFBP-4 also correlated positively with creatinine level and negatively with eGFR, in people with DN supporting its involvement in DN. CONCLUSION: The data from this study shows a parallel increase in the plasma levels of NGAL and IGFBP-4 in DN. This highlights the potential to use these markers for early diagnosis of DN.

Dysregulated Urinary Extracellular Vesicle Small RNAs in Diabetic Nephropathy: Implications for Diagnosis and Therapy.

Background: Diabetic nephropathy (DN) represents a major chronic kidney disorder and a leading cause of end-stage renal disease (ESRD). Small RNAs have been showing great promise as diagnostic markers as well as drug targets. Identifying dysregulated micro RNAs (miRNAs) could help in identifying disease biomarkers and investigation of downstream interactions, shedding light on the molecular pathophysiology of DN. In this study, we analyzed small RNAs within human urinary extracellular vesicles (ECVs) from DN patients using small RNA next-generation sequencing. Method: In this cross-sectional study, urine samples were collected from 88 participants who were divided into 3 groups: type 2 diabetes (T2D) with DN (T2D + DN, n = 20), T2D without DN (T2D - DN, n = 40), and healthy individuals (n = 28). The study focused on isolating urinary ECVs to extract and sequence small RNAs. Differentially expressed small RNAs were identified, and a functional enrichment analysis was conducted. Results: The study revealed a distinct subset of 13 miRNAs and 10 Piwi-interacting RNAs that were significantly dysregulated in urinary ECVs of the DN group when compared to other groups. Notably, miR-151a-3p and miR-182-5p exhibited a unique expression pattern, being downregulated in the T2D - DN group, and upregulated in the T2D + DN group, thus demonstrating their effectiveness in distinguishing patients between the 2 groups. Eight driver genes were identified PTEN, SMAD2, SMAD4, VEGFA, CCND2, CDK6, LIN28B, and CHD1. Conclusion: Our findings contribute valuable insights into the pathogenesis of DN, uncovering novel biomarkers and identifying potential therapeutic targets that may aid in managing and potentially decelerating the progression of the disease.

Impact of COVID-19 infection on the dialysis population prospective, observational, nationwide study.

INTRODUCTION: Hemodialysis (HD) patients are at increased risk of severe COVID-19 infection but infection rates vary. Our objectives are to describe COVID-19 positive HD patients' characteristics, infection rates, and factors associated with mortality in HD COVID-19 cases in Kuwait. METHODS: Data on demographics, comorbidities, and treatments received, as well as mortality for HD patients admitted to hospitals for COVID-19, from 1/March to 31/July 2020, prospectively collected and analyzed. RESULTS: A total of 141 infected HD patients were admitted (Mean age 58 ± 16.1; Males 56%), representing 7% of the total HD population and 0.2% of all COVID-19 cases during the study period. Of those 141 infected HD patients, 27 (19%) died, and this represents 6% of total COVID-19-related mortality and 27% of the total HD mortality. In contrast, total covid-19-related mortality of all positive cases was only 0.7%, and total HD mortality during the study period was only 5%. COVID-19-positive HD patients who died were older and 59% were males. However, the differences were not statistically significant. Of the 61 infected HD patients who needed to be switched to continuous kidney replacement therapy (CKRT), 34% died, and of the 29 infected HD patients who needed admission to intensive care, 65% died. CONCLUSION: HD population represents a small fraction of the total population; however, positive HD COVID-19 cases represent a sizable proportion of COVID-19 cases and a significant percentage of total COVID-19-related mortality, and total HD mortality.

The genetic landscape of autosomal dominant polycystic kidney disease in Kuwait.

Background: Autosomal dominant polycystic kidney disease (ADPKD) is the most common renal monogenic disease, characterized by bilateral accumulation of renal fluid-filled cysts leading to progressive renal volume enlargement and gradual impairment of kidney function, often resulting in end-stage renal disease. Kuwait could provide valuable genetic insights about ADPKD, including intrafamilial phenotypic variation, given its large household size. This study aims to provide a comprehensive description of the pathogenic variants linked to ADPKD in the Kuwaiti population using multiple genetic analysis modalities and to describe and analyse the ADPKD phenotypic spectrum in terms of kidney function, kidney volume and renal survival. Methods: A total of 126 ADPKD patients from 11 multiplex families and 25 singletons were recruited into the study. A combination of targeted next-generation sequencing (tNGS), long-range polymerase chain reaction, Sanger sequencing and multiplex ligation-dependent probe amplification were utilized for genetic diagnosis. Clinical evaluation was conducted through renal function testing and ultrasonographic kidney volume analysis. Results: We identified 29 ADPKD pathogenic mutations from 36 families achieving an overall molecular genetic diagnostic rate of 112/126 (88.9%), including 29/36 (80.6%) in families. A total of 28/36 (77.8%) families had pathogenic mutations in PKD1, of which 17/28 (60.7%) were truncating, and 1/36 (2.8%) had a pathogenic variant in the IFT140 gene. A total of 20/29 (69%) of the identified ADPKD mutations were novel and described for the first time, including a TSC2-PKD1 contiguous syndrome. Clinical analysis indicated that genetically unresolved ADPKD cases had no apparent association between kidney volume and age. Conclusion: We describe for the first time the genetic landscape of ADPKD in Kuwait. The observed genetic heterogeneity underlining ADPKD along with the wide phenotypic spectrum reveal the level of complexity in disease pathophysiology. ADPKD genetic testing could improve the care of patients through improved disease prognostication, guided treatment and genetic counselling. However, to fulfil the potential of genetic testing, it is important to overcome the hurdle of genetically unresolved ADPKD cases.

Response to and outcomes of the Pfizer BNT162B2 vaccine in hemodialysis patients-A prospective observational study.

INTRODUCTION: COVID-19 infection is associated with high mortality among hemodialysis patients. Standard vaccine response is generally lower among these patients. The adequate antibody titer response and the outcome of COVID-19 vaccine responders versus non-responders are unknown. METHODS: Hemodialysis patients on maintenance hemodialysis who have received two doses of Pfizer BNT162B2 vaccine were studied. Antibody response was tested after 14 days of the second dose. LIAISON SARS-CoV2 S1/S2 IgG test by DiaSorin (Italy) was used to assess antibody response. Patients were followed between 3 and 7 months after vaccination for COVID-19 infection, hospitalization and death related to COVID-19. FINDINGS: A total of 138 patients received two doses of Pfizer BNT162B2 vaccine. One hundred and twenty-seven patients had adequate response to the vaccine with IgG level ≥ 15 AU/ml versus 11 patients had poor response with IgG level ≤ 15 AU/ml. The response was 92% (127/138). Patient with history of prior COVID-19 infection had higher antibody titer mean of 339 ± 113 versus 157 ± 140 for patient with no prior history of COVID-19. Seven patients in both groups had COVID-19 infection post vaccine. Among the responders, five patients had COIVD-19 infection and two were hospitalized. These two patients had lower antibody titer of 23.9 and 75.2 AU/ml. In comparison, three patients who were not hospitalized had higher antibody titer 96.3, 118, and 319 AU/ml, respectively. In the non-responders one patient was hospitalized and one death occurred with rate of infection of 18%. DISCUSSION: Seropositive patients with low antibody titer might be associated with worse outcome among responders. The ideal antibody titer level among dialysis patient is not known. Also, prior COVID-19 infection is associated with higher response to vaccine with higher antibody titer. All non-responders did not have prior COVID-19 infection. More research is required to further evaluated protective antibody titer.

Potential Role of N-Cadherin in Diagnosis and Prognosis of Diabetic Nephropathy.

Diabetic nephropathy (DN) is a serious complication of diabetes affecting about half the people with diabetes and the leading cause of end stage renal disease (ESRD). Albuminuria and creatinine levels are currently the classic markers for the diagnosis of DN. However, many shortcomings are arising from the use of these markers mainly because they are not specific to DN and their levels are altered by multiple non-pathological factors. Therefore, the aim of this study is to identify better markers for the accurate and early diagnosis of DN. The study was performed on 159 subjects including 42 control subjects, 50 T2D without DN and 67 T2D subjects with DN. Our data show that circulating N-cadherin levels are significantly higher in the diabetic patients who are diagnosed with DN (842.6 ± 98.6 mg/l) compared to the diabetic patients who do not have DN (470.8 ± 111.5 mg/l) and the non-diabetic control group (412.6 ± 41.8 mg/l). We also report that this increase occurs early during the developmental stages of the disease since N-cadherin levels are significantly elevated in the microalbuminuric patients when compared to the healthy control group. In addition, we show a significant correlation between N-cadherin levels and renal markers including creatinine (in serum and urine), urea and eGFR in all the diabetic patients. In conclusion, our study presents N-cadherin as a novel marker for diabetic nephropathy that can be used as a valuable prognostic and diagnostic tool to slow down or even inhibit ESRD.

Current Status and Future of End-Stage Kidney Disease in Gulf Cooperation Council Countries: Challenges and Opportunities.

There is a paucity of data on epidemiology along with an incomplete registry of end-stage kidney disease (ESKD), nephrologist workforce, and variability among the countries of Gulf Cooperation Council (GCC). The study is an observation, descriptive study which aimed to describe current ESKD burden, nephrologist density, and kidney care infrastructure in GCC. Responses to a questionnaire-based survey obtained from representatives of the Nephrology Societies of GCC countries were analyzed. The categorical variables were compared using Chi-square test. A P = 5% was considered as significant. The mean prevalence of ESKD per million populations (pmp) was 551, highest in Oman (1000/pmp), least in Qatar (347/pmp). Predominant etiology in GCC was diabetes mellitus (DM) and hypertension (HTN) (100%, each), followed by chronic glomerulonephritis (66.7%). A transplant registry was maintained by all GCC countries. Hemodialysis (HD) (67.2%) was the most opted modality of kidney replacement therapy (KRT), followed by kidney transplantation (22%) and peritoneal dialysis (9.6%); 1.0% of patients opted for conservative management. Unplanned initiation of HD was three times more common. The access distribution among incident and prevalent HD patients respectively was (i) nontunneled central catheter (nTCC) (58.7 ± 36.6 vs. 1.5 ± 1.5), (ii) tunneled central catheter (23.5 ± 29.9 vs. 33.6 ± 10.0), and (iii) arteriovenous fistula (17.3± 14.4 vs. 57.8 ± 11.86). Death and transplantation were the reasons for dropout from HD. GCC has adequate kidney care infrastructure. There are 1686 nephrologists [range: Bahrain 9, Kingdom of Saudi Arabia (KSA) 1279]. Qatar, KSA, and Kuwait provide training in kidney biopsy; all countries except Bahrain have formal training programs for nTCC placement. ESKD prevalence is high, DM, HTN; glome-rulonephritis (GN) is the most common causes. The need for KRT is expected to rise in GCC. HD is the predominant KRT modality with a high prevalence of dialysis catheters as vascular access.

Renal Data from the Arab World Dialysis in Kuwait: 2013-2019.

The total number of end-stage kidney disease patients treated with dialysis in 2019 in Kuwait was 2230, with a 6% increase from the year before. Dialysis prevalence was 465 per million population (PMP) and dialysis incidence was100 PMP. Kuwaiti nationals represented 70% of the dialysis population and males represented 52%. Of the same population, 59% had diabetes. Hepatitis C virus affected <4% and hepatitis B virus affected <2% of the dialysis population. The annual mortality rate was stable at around 12%. Hemodialysis (HD) share was 89%, with 48% of HD patients getting HD via catheter, 54% on hemodiafiltration (HDF), and 50% dialyzing against a calcium bath of 1.75. Patients getting <3 times/week of HD constituted 10% and patients spending <3.5 h/session constituted 11%. We had only 20 dialysis patients under the age of 12 years (12 on HD). The major challenges faced included poor peritoneal dialysis penetration, the unacceptable high rates of catheters as primary HD vascular access, partly due to lack of chronic kidney disease (CKD) clinics and lack of vascular access coordinators, and the unexplained high rates of use of calcium bath of 1.75. There is also a need for a national campaign for early detection and prevention of CKD to reduce rates of end-stage renal disease.