Incidence and outcomes of kidney replacement therapy for end-stage kidney disease due to primary glomerular disease in Europe: findings from the ERA Registry.

BACKGROUND AND HYPOTHESIS: Primary glomerular disease (PGD) is a major cause of end-stage kidney disease (ESKD) leading to kidney replacement therapy (KRT). We aimed to describe incidence (trends) in individuals starting KRT for ESKD due to PGD and to examine their survival and causes of death. METHODS: We used data from the European Renal Association (ERA) Registry on 69 854 patients who started KRT for ESKD due to PGD between 2000 and 2019. ERA primary renal disease codes were used to define six PGD subgroups. We examined age and sex standardized incidence, trend of the incidence, and survival. RESULTS: The standardized incidence of KRT for ESKD due to PGD was 16.6 per million population (pmp), ranging from 8.6 pmp in Serbia to 20.0 pmp in France. IgA nephropathy (IgAN) and focal segmental glomerulosclerosis (FSGS) had the highest incidence of 4.6 pmp and 2.6 pmp, respectively. Histologically non-examined PGDs represented over 50% of cases in Serbia, Bosnia and Herzegovina, and Romania and were also common in Greece, Estonia, Belgium, and Sweden. The incidence declined from 18.6 pmp in 2000 to 14.5 pmp in 2013, after which it stabilized. All PGD subgroups had five-year survival probabilities above 50%, with crescentic glomerulonephritis having the highest risk of death (adjusted hazard ratio: 1.8 [95% confidence interval: 1.6-1.9]) compared with IgAN. Cardiovascular disease was the most common cause of death (33.9%). CONCLUSION: The incidence of KRT for ESKD due to PGD showed large differences between countries and was highest and increasing for IgAN and FSGS. Lack of kidney biopsy facilities in some countries may have affected accurate assignment of the cause of ESKD. The recognition of the incidence and outcomes of KRT among different PGD subgroups may contribute to a more individualized patient care approach.

Comparison of whole body versus thoracic bioimpedance in relation to ultrafiltration volume and systolic blood pressure during hemodialysis.

In contrast to whole body bioimpedance, which estimates fluid status at a single point in time, thoracic bioimpedance applied by a wearable device could enable continuous measurements. However, clinical experience with thoracic bioimpedance in patients on dialysis is limited. To test the reproducibility of whole body and thoracic bioimpedance measurements and to compare their relationship with hemodynamic changes during hemodialysis, these parameters were measured pre- and end-dialysis in 54 patients during two sessions. The resistance from both bioimpedance techniques was moderately reproducible between two dialysis sessions (intraclass correlations of pre- to end-dialysis whole body and thoracic resistance between session 1 and 2 were 0.711 [0.58-0.8] and 0.723 [0.6-0.81], respectively). There was a very high to high correlation between changes in ultrafiltration volume and changes in whole body thoracic resistance. Changes in systolic blood pressure negatively correlated to both bioimpedance techniques. Although the relationship between changes in ultrafiltration volume and changes in resistance was stronger for whole body bioimpedance, the relationship with changes in blood pressure was at least comparable for thoracic measurements. These results suggest that thoracic bioimpedance, measured by a wearable device, may serve as an interesting alternative to whole body measurements for continuous hemodynamic monitoring during hemodialysis.NEW & NOTEWORTHY We examined the role of whole body and thoracic bioimpedance in hemodynamic changes during hemodialysis. Whole body and thoracic bioimpedance signals were strongly related to ultrafiltration volume and moderately, negatively, to changes in blood pressure. This work supports the further development of a wearable device measuring thoracic bioimpedance longitudinally in patients on hemodialysis. As such, it may serve as an innovative tool for continuous hemodynamic monitoring during hemodialysis in hospital or in a home-based setting.

Pre-treatment bicarbonate levels and decongestion by acetazolamide: the ADVOR trial.

AIMS: Acetazolamide inhibits proximal tubular sodium and bicarbonate re-absorption and improved decongestive response in acute heart failure in the ADVOR trial. It is unknown whether bicarbonate levels alter the decongestive response to acetazolamide. METHODS AND RESULTS: This is a sub-analysis of the randomized, double-blind, placebo-controlled ADVOR trial that randomized 519 patients with acute heart failure and volume overload in a 1:1 ratio to intravenous acetazolamide (500 mg/day) or matching placebo on top of standardized intravenous loop diuretics (dose equivalent of twice oral maintenance dose). The primary endpoint was complete decongestion after 3 days of treatment (morning of day 4). Impact of baseline HCO3 levels on the treatment effect of acetazolamide was assessed. : Of the 519 enrolled patients, 516 (99.4%) had a baseline HCO3 measurement. Continuous HCO3 modelling illustrated a higher proportional treatment effect for acetazolamide if baseline HCO3 ≥ 27 mmol/l. A total of 234 (45%) had a baseline HCO3 ≥ 27 mmol/l. Randomization towards acetazolamide improved decongestive response over the entire range of baseline HCO3- levels (P = 0.004); however, patients with elevated baseline HCO3 exhibited a significant higher response to acetazolamide [primary endpoint: no vs. elevated HCO3; OR 1.37 (0.79-2.37) vs. OR 2.39 (1.35-4.22), P-interaction = 0.065), with higher proportional diuretic and natriuretic response (both P-interaction < 0.001), greater reduction in congestion score on consecutive days (treatment × time by HCO3-interaction <0.001) and length of stay (P-interaction = 0.019). The larger proportional treatment effect was mainly explained by the development of diminished decongestive response in the placebo arm (loop diuretics only), both with regard to reaching the primary endpoint of decongestion as well as reduction in congestion score. Development of elevated HCO3 further worsened decongestive response in the placebo arm (P-interaction = 0.041). A loop diuretic only strategy was associated with an increase in the HCO3 during the treatment phase which was prevented by acetazolamide (day 3: placebo 74.8% vs. acetazolamide 41.3%, P < 0.001). CONCLUSION: Acetazolamide improves decongestive response over the entire range of HCO3- levels; however, the treatment response is magnified in patients with baseline or loop diuretic-induced elevated HCO3 (marker of proximal nephron NaHCO3 retention) by specifically counteracting this component of diuretic resistance.

Population-wide persistent hemostatic changes after vaccination with ChAdOx1-S.

Various vaccines were developed to reduce the spread of the Severe Acute Respiratory Syndrome Cov-2 (SARS-CoV-2) virus. Quickly after the start of vaccination, reports emerged that anti-SARS-CoV-2 vaccines, including ChAdOx1-S, could be associated with an increased risk of thrombosis. We investigated the hemostatic changes after ChAdOx1-S vaccination in 631 health care workers. Blood samples were collected 32 days on average after the second ChAdOx1-S vaccination, to evaluate hemostatic markers such as D-dimer, fibrinogen, α2-macroglobulin, FVIII and thrombin generation. Endothelial function was assessed by measuring Von Willebrand Factor (VWF) and active VWF. IL-6 and IL-10 were measured to study the activation of the immune system. Additionally, SARS-CoV-2 anti-nucleoside and anti-spike protein antibody titers were determined. Prothrombin and fibrinogen levels were significantly reduced after vaccination (-7.5% and -16.9%, p < 0.0001). Significantly more vaccinated subjects were outside the normal range compared to controls for prothrombin (42.1% vs. 26.4%, p = 0.026) and antithrombin (23.9% vs. 3.6%, p = 0.0010). Thrombin generation indicated a more procoagulant profile, characterized by a significantly shortened lag time (-11.3%, p < 0.0001) and time-to-peak (-13.0% and p < 0.0001) and an increased peak height (32.6%, p = 0.0015) in vaccinated subjects compared to unvaccinated controls. Increased VWF (+39.5%, p < 0.0001) and active VWF levels (+24.1 %, p < 0.0001) pointed toward endothelial activation, and IL-10 levels were significantly increased (9.29 pg/mL vs. 2.43 pg/mL, p = 0.032). The persistent increase of IL-10 indicates that the immune system remains active after ChAdOx1-S vaccination. This could trigger a pathophysiological mechanism causing an increased thrombin generation profile and vascular endothelial activation, which could subsequently result in and increased risk of thrombotic events.

Predictors and Dynamics of the Humoral and Cellular Immune Response to SARS-CoV-2 mRNA Vaccines in Hemodialysis Patients: A Multicenter Observational Study.

BACKGROUND: Preliminary evidence suggests patients on hemodialysis have a blunted early serological response to SARS-CoV-2 vaccination. Optimizing the vaccination strategy in this population requires a thorough understanding of predictors and dynamics of humoral and cellular immune responses to different SARS-CoV-2 vaccines. METHODS: This prospective multicenter study of 543 patients on hemodialysis and 75 healthy volunteers evaluated the immune responses at 4 or 5 weeks and 8 or 9 weeks after administration of the BNT162b2 or mRNA-1273 vaccine, respectively. We assessed anti-SARS-CoV-2 spike antibodies and T cell responses by IFN-γ secretion of peripheral blood lymphocytes upon SARS-CoV-2 glycoprotein stimulation (QuantiFERON assay) and evaluated potential predictors of the responses. RESULTS: Compared with healthy volunteers, patients on hemodialysis had an incomplete, delayed humoral immune response and a blunted cellular immune response. Geometric mean antibody titers at both time points were significantly greater in patients vaccinated with mRNA-1273 versus BNT162b2, and a larger proportion of them achieved the threshold of 4160 AU/ml, corresponding with high neutralizing antibody titers in vitro (53.6% versus 31.8% at 8 or 9 weeks, P <0.0001). Patients vaccinated with mRNA-1273 versus BNT162b2 exhibited significantly greater median QuantiFERON responses at both time points, and a larger proportion achieved the threshold of 0.15 IU/ml (64.4% versus 46.9% at 8 or 9 weeks, P <0.0001). Multivariate analysis identified COVID-19 experience, vaccine type, use of immunosuppressive drugs, serum albumin, lymphocyte count, hepatitis B vaccine nonresponder status, and dialysis vintage as independent predictors of the humoral and cellular responses. CONCLUSIONS: The mRNA-1273 vaccine's greater immunogenicity may be related to its higher mRNA dose. This suggests a high-dose vaccine might improve the impaired immune response to SARS-CoV-2 vaccination in patients on hemodialysis.

"Time is tissue"-A minireview on the importance of donor nephrectomy, donor hepatectomy, and implantation times in kidney and liver transplantation.

Donor organs are exposed to sequential temperature changes during the transplantation process. The role of donor warm ischemia and cold ischemia times on post-transplant outcomes has been extensively studied. Much less attention has been paid to the transient ischemia occurring during donor organ removal and implantation. Recently, it has become clear that prolonged donor nephrectomy and implantation time are independently associated with delayed graft function after kidney transplantation. In addition, implantation time correlates with post-transplant kidney graft function, histology, and survival. Similar detrimental associations of donor hepatectomy and implantation time with early allograft dysfunction, ischemic cholangiopathy, and graft and patient survival after liver transplantation have been demonstrated. This review details kidney and liver temperature changes occurring during procurement and transplantation. It summarizes the effects of the ischemia the kidney and liver sustain during these phases on short- and long-term post-transplant outcomes, advocating the standardized reporting of donor hepatectomy, donor nephrectomy, and implantation times in (inter)national registries. The review also explores strategies to protect the graft from this ischemic injury.

Increased Intra-Abdominal Pressure During Laparoscopic Pneumoperitoneum Enhances Albuminuria via Renal Venous Congestion, Illustrating Pathophysiological Aspects of High Output Preeclampsia.

Intra-abdominal hypertension (IAH) causes severe organ dysfunction. Our aim is to evaluate the effect of increased intra-abdominal pressure (IAP) on renal function, hypothesizing that venous congestion may increase proteinuria and fluid retention without endothelial dysfunction. Three urine samples were collected from 32 non-pregnant women undergoing laparoscopic-assisted vaginal hysterectomy (LAVH) and from 10 controls placed in Trendelenburg position for 60 min. Urine sampling was done before (PRE), during or immediately after (PER), and two hours after (POST) the procedure. Urinary albumin, protein and creatinine concentrations were measured in each sample, and ratios were calculated and compared within and between groups. During LAVH, the albumin/creatinine ratio (ACR) increased and persisted POST-procedure, which was not observed in controls. A positive correlation existed between the LAVH duration and the relative change in both ACR and protein/creatinine ratio (PCR) PER- and POST-procedure. Iatrogenic IAH increases urinary ACR and PCR in non-pregnant women via a process of venous congestion. This mechanism might explain the presentation of one specific subtype of late-onset preeclampsia, where no drop of maternal cardiac output is observed.

Age-related changes in DNA methylation affect renal histology and post-transplant fibrosis.

During ageing, kidney function decreases due to renal tubular atrophy, interstitial fibrosis, glomerulosclerosis and arteriosclerosis. Recently, changes in DNA methylation were shown to contribute to various ageing processes. However, it is unknown whether such changes also contribute to age-related kidney dysfunction. To assess this, we profiled genome-wide changes in DNA methylation (over 800 000 CpG sites) in 95 renal biopsies obtained prior to kidney transplantation from donors aged 16 to 73 years. Donor age significantly associated with the methylation of 92 778 CpGs (false discovery rate under 0.05), corresponding to 10 285 differentially methylated regions. These regions were most frequently located in genes involved in the Wnt/beta-catenin signaling pathway. Using an independent cohort of 67 biopsies, we autonomously validated these findings. Interestingly, the methylation status of these 92 778 age-related CpGs was associated with glomerulosclerosis (34.4% of CpGs at a false discovery rate under 0.05) and interstitial fibrosis (0.9%) and graft function at one year after transplantation, but not with tubular atrophy and arteriosclerosis. No association was observed with any of these pathologies at the time of transplantation (0% at a false discovery rate under 0.05). Thus, age-associated changes in DNA methylation at the time of transplantation predict future injury of transplanted kidneys. Specifically, our epigenome-wide association study demonstrates that epigenetic renal ageing is implicated in progressive fibrosis in both the glomerulus and the interstitium.

Natural killer cell infiltration is discriminative for antibody-mediated rejection and predicts outcome after kidney transplantation.

Despite partial elucidation of the pathophysiology of antibody-mediated rejection (ABMR) after kidney transplantation, it remains largely unclear which of the involved immune cell types determine disease activity and outcome. We used microarray transcriptomic data from a case-control study (n=95) to identify genes that are differentially expressed in ABMR. Given the co-occurrence of ABMR and T-cell-mediated rejection (TCMR), we built a bioinformatics pipeline to distinguish ABMR-specific mRNA markers. Differential expression of 503 unique genes was identified in ABMR, with significant enrichment of natural killer (NK) cell pathways. CIBERSORT (Cell type Identification By Estimating Relative Subsets Of known RNA Transcripts) deconvolution analysis was performed to elucidate the corresponding cell subtypes and showed increased NK cell infiltration in ABMR in comparison to TCMR and normal biopsies. Other leukocyte types (including monocytes/macrophages, CD4 and CD8 T cells, and dendritic cells) were increased in rejection, but could not discriminate ABMR from TCMR. Deconvolution-based estimation of NK cell infiltration was validated using computerized morphometry, and specifically associated with glomerulitis and peritubular capillaritis. In an external data set of kidney transplant biopsies, activated NK cell infiltration best predicted graft failure amongst all immune cell subtypes and even outperformed a histologic diagnosis of acute rejection. These data suggest that NK cells play a central role in the pathophysiology of ABMR and graft failure after kidney transplantation.

Ischemia-Induced DNA Hypermethylation during Kidney Transplant Predicts Chronic Allograft Injury.

Background Ischemia during kidney transplant causes chronic allograft injury and adversely affects outcome, but the underlying mechanisms are incompletely understood. In tumors, oxygen shortage reduces the DNA demethylating activity of the ten-11 translocation (TET) enzymes, yielding hypermethylated genomes that promote tumor progression. We investigated whether ischemia similarly induces DNA hypermethylation in kidney transplants and contributes to chronic injury.Methods We profiled genome-wide DNA methylation in three cohorts of brain-dead donor kidney allograft biopsy specimens: a longitudinal cohort with paired biopsy specimens obtained at allograft procurement (preischemia; n=13), after implantation and reperfusion (postischemia; n=13), and at 3 or 12 months after transplant (n=5 each); a cross-sectional cohort with preimplantation biopsy specimens (n=82); and a cross-sectional cohort with postreperfusion biopsy specimens (n=46).Results Analysis of the paired preischemia and postischemia specimens revealed that methylation increased drastically in all allografts on ischemia. Hypermethylation was caused by loss of 5-hydroxymethylcytosine, the product of TET activity, and it was stable 1 year after transplant. In the preimplantation cohort, CpG hypermethylation directly correlated with ischemia time and for some CpGs, increased 2.6% per additional hour of ischemia. Hypermethylation preferentially affected and reduced the expression of genes involved in suppressing kidney injury and fibrosis. Moreover, CpG hypermethylation in preimplantation specimens predicted chronic injury, particularly fibrosis and glomerulosclerosis, 1 year after transplant. This finding was validated in the independent postreperfusion cohort, in which hypermethylation also predicted reduced allograft function 1 year after transplant, outperforming established clinical variables.Conclusions We highlight a novel epigenetic basis for ischemia-induced chronic allograft injury with biomarker potential.

Inflammatory macrophage-associated 3-gene signature predicts subclinical allograft injury and graft survival.

Late allograft failure is characterized by cumulative subclinical insults manifesting over many years. Although immunomodulatory therapies targeting host T cells have improved short-term survival rates, rates of chronic allograft loss remain high. We hypothesized that other immune cell types may drive subclinical injury, ultimately leading to graft failure. We collected whole-genome transcriptome profiles from 15 independent cohorts composed of 1,697 biopsy samples to assess the association of an inflammatory macrophage polarization-specific gene signature with subclinical injury. We applied penalized regression to a subset of the data sets and identified a 3-gene inflammatory macrophage-derived signature. We validated discriminatory power of the 3-gene signature in 3 independent renal transplant data sets with mean AUC of 0.91. In a longitudinal cohort, the 3-gene signature strongly correlated with extent of injury and accurately predicted progression of subclinical injury 18 months before clinical manifestation. The 3-gene signature also stratified patients at high risk of graft failure as soon as 15 days after biopsy. We found that the 3-gene signature also distinguished acute rejection (AR) accurately in 3 heart transplant data sets but not in lung transplant. Overall, we identified a parsimonious signature capable of diagnosing AR, recognizing subclinical injury, and risk-stratifying renal transplant patients. Our results strongly suggest that inflammatory macrophages may be a viable therapeutic target to improve long-term outcomes for organ transplantation patients.

A Global Risk Score (GRS) to Simultaneously Predict Early and Late Tumor Recurrence Risk after Resection of Hepatocellular Carcinoma.

OBJECTIVES: Recurrence of hepatocellular carcinoma can arise from the primary tumor ("early recurrence") or de novo from tumor formation in a cirrhotic environment ("late recurrence"). We aimed to develop one simple gene expression score applicable in both the tumor and the surrounding liver that can predict the recurrence risk. METHODS: We determined differentially expressed genes in a cell model of cancer aggressiveness. These genes were first validated in three large published data sets of hepatocellular carcinoma from which we developed a seven-gene risk score. RESULTS: The gene score was applied on two independent large patient cohorts. In the first cohort, with only tumor data available, it could predict the recurrence risk at 3 years after resection (68 ± 10% vs 35 ± 7%, P = .03). In the second cohort, when applied on the tumor, this gene score predicted early recurrence (62 ± 5% vs 37 ± 4%, P < .001), and when applied on the surrounding liver tissue, the same genes also correlated with late recurrence. Four patient classes with each different time patterns and rates of recurrence could be identified based on combining tumor and liver scores. In a multivariate Cox regression analysis, our gene score remained significantly associated with recurrence, independent from other important cofactors such as disease stage (P = .007). CONCLUSIONS: We developed a Global Risk Score that is able to simultaneously predict the risk of early recurrence when applied on the tumor itself, as well as the risk of late recurrence when applied on the surrounding liver tissue.