bluuebunny/crossref_metadata_2025 huggingface dataset:
#2645 Clinical features and outcomes of steroid resistant focal sclerosing glomerulosclerosis (FSGS) in a single tertiary nephrology centre in Malaysia
Authors: Arimuthu Durga Arinandini , Lim Christopher Thiam Seong , Ibrahim Fairol Huda , Goh Bak Leong
Published: May 2024

Background and Aims

Steroid resistant FSGS is defined as persistence of proteinuria with <50% reduction from baseline despite prednisolone 1 mg/kg/d for at least 16 weeks. We aim to study the clinical presentations, treatment, treatment response and kidney survival among steroid resistant FSGS patients.

Method

This retrospective study included all patients who had undergone renal biopsy in HSIS and had documented diagnosis of steroid resistant FSGS from January 2007 until December 2022. Data was collected and analysed using SPSS version 17. Results are expressed in mean ± standard deviation (SD) unless stated otherwise.

Results

A total of 74 patients had primary FSGS out of which 15 were identified as steroid resistant. Median age was 33 years old with 53% being female. Median weight at diagnosis was 73.7kg with BMI of 28kg/m2. One third had no co-morbid disease while 4 patients had underlying diagnosis of minimal change disease. Proteinuria on presentation was 7.6g with albumin levels of 16 g/L. No difference was seen between steroid resistant and steroid sensitive cohort with regards to age, proteinuria, GFR and laboratory parameters. Median duration of steroid was 38.8 months with duration of high dose steroids were 5 months and complications often set in by 2 months of therapy. Steroid toxicity occurred in 13 patients with most common complication seen was Cushingoid features (8/13) followed by acne (2/13) and diabetes mellitus (2/13). There were more steroid complications in steroid resistant cohort compared to the steroid sensitive. Second line was initiated in all patients but one with cyclosporin A being the most common choice (11/14) followed by Azathioprine (2/14) and cyclophosphamide (3/14). The median duration of second line agent was 22 months with CNI specifically being for 18 months. 3 patients developed CNI toxicity and was given cyclophosphamide while one patient developed CNI resistance and was given IV Rituximab. 4 (%) patients went on to achieve complete remission, 8 had partial remission while the rest did not achieve remission. 9 patients had normal renal function, while 3 developed chronic kidney disease. One patient went on to become end stage renal disease while 2 patients died. There was no difference in terms of renal or patient outcome between steroid resistant and steroid sensitive FSGS.

Conclusion

Steroid resistant FSGS is a challenging entity of FSGS that warrants close monitoring for complications and management. The outcomes were not different between steroid sensitive and steroid resistant FSGS however, the steroid complications were more common in steroid resistant FSGS.
#2691 Treatment naive membranous nephropathy patients treated with rituximab in COVID19 era
Authors: Brinar Ivana Vukovic , Stanusic Ivana , Ivandic Ema , Prlic Margareta Fistrek , Bulimbasic Stela , Ćorić Marijana , Kurtov Karlo , Kos Jelena , Jelakovic Ana , Jelaković Bojan
Published: May 2024

Background and Aims

Standard of care of high-risk idiopathic membranous nephropathy patients is immunosuppressive treatment with cyclophosphamide and corticosteroids or rituximab. Our aim was to assess outcome and safety of rituximab therapy in COVID19 era in comparison to modified Ponticelli protocol.

Method

In this retrospective study all adult patients with biopsy proven membranous nephropathy treated with rituximab as a first line therapy from 2020 till 2022 were enrolled and compared with MN patients treated with modified Ponticelli protocol from 2013 till 2020. Renal outcome was defined as composite of partial and complete remission defined according KDIGO guidelines. Except otherwise stated, data are shown as N (%) or median with interquartile range (IQR) and accompanied p levels.

Results

During the COVID 19 era, between 2020 and 2022, 8 MN patients were treated with rituximab as a first line therapy. One was lost from follow up and one had allergic infusion reaction and therefore was excluded from further analysis. Ten patients were treated with modified Ponticelli protocol. There was no difference in age (60 vs. 59 years; p = 0.669), gender (M 57.1 vs. 60%), BMI (26.3 vs. 29.1cm/kg; p = 0.906), systolic (140. vs. 150 mmHg; p = 0.161) or diastolic (90 vs. 91.5 mmHg; p = 0.230) blood pressure between rituximab and cyclophosphamide treated group. Also, there was no difference in proteinuria between rituximab and cyclophosphamide treated group (16.2 (5.7–31.3) vs. 8.7 (6.5–12.5) g/dU; p = 0.201) Patients treated with cyclophosphamide had lower eGFR compared with patients treated with rituximab (51 (34-79) vs. 93 (72-98) ml/min/1,73 m²; p = 0.005). At 6 months follow up only 2 (28.6%) in rituximab group and 6 (60%) in cyclophosphamide group achieved outcome defined as composite of complete and partial remission. At one year follow up, there was no difference in outcome between groups and all patients from rituximab group compared to 8 patients (88.9%) from cyclophosphamide group accomplished composite favorable renal outcome (p = 398). At the end of follow up, one year after cyclophosphamide therapy eGFR was better (57 (43-96) vs. 51 (34-79) ml/min/1,73 m²). Rituximab was safe in our cohort. Three (50%) of patients acquired SARS CoV2 infection and there was no adverse outcome regarding COVID 19 disease.

Conclusion

Cyclophosphamide is faster than rituximab in accomplishing remission of nephrotic syndrome and improves deteriorated kidney function. Nevertheless, at 1 year follow up rituximab efficiency is proven to be excellent. Cyclophosphamide should be reserved for MN patients with nephrotic syndrome with reduced glomerular filtration rate.
#211 Low albumin levels are associated with intrarenal complement C4d deposits in critically ill patients with ANCA-associated renal vasculitides
Authors: Baier Eva , Kluge Ingmar , Korsten Peter , Hakroush Samy , Tampe Björn
Published: May 2024

Background and Aims

Despite serum albumin levels being predictive for clinical outcome in ANCA-associated renal vasculitis, implications providing a direct link between low serum albumin levels and intrarenal lesions remain elusive. Therefore, we here aimed to systematically assess the clinical relevance of low albumin levels and scrutinize clinicopathological correlations to expand our current knowledge.

Method

We here retrospectively enrolled biopsy-proven cases of ANCA-associated renal vasculitis between 2015 till 2020 in a single-center observational study. Survival-curve analyses on long-term renal survival and short-term clinical recovery were performed. Correlative analyses between serum albumin levels, laboratory parameters, proteinuria levels, and histopathological lesions including tubulointerstitial immune cell infiltrates, lesions analogous to the Banff score and intrarenal complement deposition of C3c and C4d were performed.

Results

We here show that hypoalbuminemia below the median of 2.4 g/dL impairs long-term renal survival especially in MPO-positive ANCA-associated renal vasculitis (p = 0.006, HR: 5.0, 95% CI: 1.2-21.5), while short-term clinical recovery particularly in critically ill patients is negatively affected by low serum albumin levels (p = 0.0082, HR: 3.6, 95% CI: 1.1-11.7). Low albumin levels are associated with the urinary marker of tubular damage in the total cohort (β = −0.5, p = 0.01), PR3-ANCA (β = −0.5, p = 0.04) and MPO-ANCA (p = 0.002, β = −0.8), but not in critically ill patients (β = −0.5, p = 0.07) implying hypoalbuminemia to occur by extrarenal causation in the state of critical illness. We identified plasmacytic infiltrates to correlate with low albumin levels in the total cohort (β = −0.6, p = 0.004) and in the subgroup of critically ill patients (β = −0.7, p = 0.005). Banff-scored interstitial inflammation (i) was further observed to inversely correlate with albumin levels (β = −0.7, p = 0.02). Intrarenal C4d deposition showed a significant correlation with low serum albumin levels in the glomerular tuft (β = −0.4, p = 0.04) and in interstitial arteries (β = −0.7, p = 0.01).

Conclusion

In conclusion, long-term renal outcome is significantly affected by low serum albumin levels especially in the setting of MPO-ANCA seropositivity. By contrast, short-term recovery was predicted by low albumin levels in critically ill patients with ANCA-associated renal vasculitis. We here provide evidence that low levels of serum albumin might directly affect tubulointerstitial inflammation as reflected by plasmacytic immune-cell infiltration, and intrarenal C4d complement deposition in ANCA-associated renal vasculitis.
#1425 Anemia in patients with IgA nephropathy: an impact on the prognosis of IgA nephropathy
Authors: Kim Kyu Yeun , Park Sun-Hee , Yoo Jieun , Kim Mingyu , Kim Yoon-Ju , Jeon You-Hyun , Lim Jeong-Hoon , Jung hee-Yeon , Choi Ji-Young , Cho Jang-Hee , Kim Chan Duck , Kim Yong-Lim
Published: May 2024

Background and Aims

Immunoglobulin A Nephropathy (IgAN) has several well-known predictors of renal outcomes, including persistent proteinuria, hypertension, and baseline eGFR at the time of diagnosis. However, the effect of hemoglobin (Hb) levels on the progression of IgAN is rarely reported. This study aims to evaluate the impact of Hb levels on the prognosis of IgAN and to identify risk factors for anemia in patients with IgAN.

Method

A retrospective analysis of the data of 855 patients diagnosed with IgAN at Kyungpook National University Hospital between January 2002 and December 2021 was performed. We obtained the data on clinical parameters and pathological findings according to the Oxford classification at the time of the kidney biopsy. Univariate and multivariate logistic regression analyses were used to evaluate the risk factors for anemia, and a Cox proportional hazard model was used to estimate the effects of anemia on the development of end-stage kidney disease (ESKD).

Results

Lower serum albumin, lower eGFR, severe interstitial fibrosis, and tubular atrophy were associated with anemia in patients with IgAN. The Kaplan-Meier survival curve revealed that patients with anemia had worse renal survival than those without anemia. The multivariable Cox analysis showed that anemia was an independent risk for the progression to ESKD (HR 2.86, confidence interval 1.58–5.17, p = 0.001). In a sex-specific analysis, only the female sex showed a significant and higher risk for ESKD (hazard ratio 4.07, confidence interval 1.53–10.8, p = 0.005).

Conclusion

A low Hb level at the time of biopsy, even if subclinical, was an independent risk factor for the development of ESKD in patients with IgAN. Therefore, it is necessary to monitor Hb levels at the time of diagnosis and take proactive measures to reduce the risk of disease progression.
#886 Prevalence and prognostic relevance of electrocardiographic abnormalities among patients with ANCA-associated vasculitis
Authors: Nygaard Louis , Liboriussen Caroline Hundborg , Carlson Nicholas , Nelveg-Kristensen Karl Emil , Kristensen Salome , Kragholm Kristian , Graff Claus , Torp Christian , Ivarsen Per , Svensson My , Gregersen Jon Waarst , Polcwiartek Christoffer
Published: May 2024

Background and Aims

Cardiovascular disease (CVD) is one of the leading causes of death in patients with ANCA-associated vasculitis (AAV). However, in current clinical guidelines, limited evidence is available to support the recommendation of AAV-specific screening for cardiovascular comorbidities. This study reported the prevalence of electrocardiogram (ECG) abnormalities and investigated associations between ECG abnormalities and fatal CVD in a validated cohort of patients with AAV compared to matched controls.

Method

Based on a retrospective matched cohort design, patients with granulomatosis with polyangiitis [ICD-10: DM31.3] or microscopic polyangiitis [ICD-10: DM3.17] and accessible ECGs were identified in nationwide Danish health care registers from 2000 to 2021. Patients with AAV were matched 1:3 on age, sex, and calendar year of ECG measurement with controls without AAV. Index date was defined as the date of ECG measurement. ECGs were hierarchically categorized as either no, minor, or major ECG abnormalities according to contemporary literature. The associations between ECG abnormalities and fatal CVD were assessed in multiple Cox regression models adjusted for age, sex, and comorbidities. Counterfactual G-estimation of hazard ratios (HRs) standardized to age and sex was performed to estimate the 5-year absolute risk (AR) of fatal CVD according to ECG-abnormalities.

Results

A total of 1431 patients with AAV were matched to 4293 controls. The median age of patients with AAV and matched controls was 69 (IQR 58-77) years, and 52.3% were males. Median study follow-up time was 4.8 (IQR, 2.7-7.8) years. AAV was associated with increased prevalence of left ventricular hypertrophy (17.5% vs. 12.5%, p < 0.001), ST-T deviations (10.1% vs. 7.1%, p < 0.001), atrial fibrillation (9.6% vs. 7.5%, p = 0.017) and corrected QT prolongation (5.9% vs. 3.6%, p < 0.001) compared to controls. When examining associations of fatal CVD across no, minor or major ECG abnormalities, only the patients with AAV and major ECG abnormalities had a higher risk of fatal CVD [HR 1.99 (95% CI, 1.49-2.65)], compared to matched controls. This corresponded to a significantly higher standardized 5-year AR of fatal CVD compared to controls: 19.14% (95% CI, 16-22%) vs. 9.41% (95% CI, 8-11%).

Conclusion

AAV was associated with a higher prevalence of major ECG abnormalities such as left ventricular hypertrophy, atrial fibrillation, and ST-T deviations compared to matched controls. Moreover, the patients with AAV demonstrating major ECG abnormalities had a particularly elevated risk of fatal CVD. This indicates that AAV patients with major ECG abnormalities are a distinct high-risk group within AAV patients prone to cardiovascular-related mortality.
#634 Prognosis is still poor in patients with posttransplant C3 glomerulopathy: a multicenter cohort
Authors: Mirioglu Safak , Hocaoglu Rabia Hacer , Velioglu Arzu , Ozluk Yasemin , Dirim Ahmet Burak , Oruc Aysegul , Oto Ozgur Akin , Yazici Halil , Caliskan Yasar
Published: May 2024

Background and Aims

Data on patients with posttransplant recurrent or de novo C3 glomerulopathy (C3G) are limited. We therefore aimed to analyze features and outcomes of patients developed posttransplant C3G.

Method

In this retrospective multicenter study conducted across 3 centers, we collected the data of kidney transplant recipients (KTRs) who were diagnosed with posttransplant recurrent or de novo C3G between 2014-2023 and followed for at least 3 months after the diagnosis. Demographic, clinical, laboratory and histopathological characteristics of patients were retrieved from the databases of participating centers. Primary outcome was defined as death-censored graft loss necessitating dialysis or re-transplantation, and secondary outcome was complete (CR) or partial remission (PR). CR was the recovery of baseline eGFR and proteinuria of <0.5 g/g. PR was ≥50% reduction of proteinuria (and to <3 g/g in patients with nephrotic-range proteinuria at baseline) plus stabilization or improvement in kidney function.

Results

Eleven patients were identified, and 10 with follow-up data were included. Detailed features of patients were shown in the Table. Five (50%) were male, and mean age at the time of transplantation (KTx) was 33.2 ± 8.5 years. Nine KTRs (90%) were diagnosed with recurrent C3G and the etiology of primary kidney disease was not known in one patient. Majority of KTx were performed from living donors (9.90%). One patient had a history of T-cell mediated rejection before posttransplant C3G, which had showed good response to anti-rejection treatment. Posttransplant C3G was diagnosed after a median of 26 (3-85) months after KTx, and mean age was 36.8 ± 9.1 years. Mean hemoglobin, serum creatinine, serum albumin, and proteinuria at the time of diagnosis were 10.5 ± 1.8 g/dl, 1.9 ± 0.7 mg/dl, 4.1 ± 0.5 g/dl, and 1.1 ± 0.9 g/g, respectively. Monoclonal disorders were excluded by using serum and urine electrophoresis and serum free light chain assays in all KTRs. Serum C3 was low (67.1 ± 29.7 mg/dl, ref: 90-180 mg/dl) in 7 of 8 KTRs with available data (87.5%). Further immunosuppressive treatment was administered in 9 cases. Eculizumab was used in 8, and 1 patient was treated with pulse steroids and therapeutic plasma exchange. Median duration of treatment was 14.5 (3-24.3) months. Four patients (44.4%) who were treated with eculizumab showed CR. After a median of 32 (9.5-82) months, 5 KTRs (50%) experienced graft loss despite eculizumab use in 3 of them. No adverse events attributed to treatment were observed.

Conclusion

Prognosis is still quite dismal in patients with posttransplant C3G despite the use of eculizumab. Better treatment options are urgently needed.
#753 Targeted anti-IL-1β bacteroides fragilis outer membrane vesicles alleviate inflammatory injury in diabetic nephropathy
Authors: LI Liang , LI Xue Qi , Zhang Jia Xiu , Wu Qin Yi , MA Kun Ling
Published: May 2024

Background and Aims

It is accepted that diabetic nephropathy (DN) is not only a disease caused by impaired glucose metabolism, but also a chronic inflammatory disease. The interleukin-1β (IL-1β) plays an important role in inflammation-mediated renal injury in DN. IL-1β blocking therapy can prevent inflammatory cytokine-mediated kidney injury. However, the high cost and systemic side effects of IL-1β antibodies limit its application. Therefore, firstly this study aimed to construct kidney-targeting outer membrane vesicles (OMVs) of Bacteroides fragilis loaded with IL-1β single-chain variable fragment (scFv). These OMVs derived from human commensal non-toxigenic Bacteroides fragilis have been proven to play an immunosuppressive role in the intestine and distant organs. This targeted drug delivery platform built with this as a carrier is expected to relieve kidney inflammation in the development of DN.

Methods

We recombinantly expressed the scFv based on the Gevokizumab sequence in Escherichia coli, and loaded it into the OMVs derived from Bacteroides fragilis by multiple ultrasounds. The targeting peptide with the sequence (KKEEE)3{Lys(N3)} was connected to the membrane surface through a copper-free catalyzed click chemistry reaction. The package, which consisted of OMVs and the scFv targeting IL-1β in the kidney (OMV-KTP-scFv) was obtained. OMV-KTP-scFv treated in HK-2 cells and healthy mice respectively, and evaluated its in vitro and in vivo drug safety. The concentration of IL-1β scFv in blood and kidney tissues at different time points were measured using streptozotocin (STZ)-induced diabetic mice. DID-labeled OMVs was used for ex vivo infrared imaging of various organs to evaluate the delivery efficiency of the targeted carrier. In vitro, OMV-KTP-scFv was used to prevent inflammation in mouse primary renal tubular epithelial cells induced by high glucose, and in vivo to alleviate kidney injury in STZ-induced diabetic mice.

Results

We successfully prepared OMV-KTP-scFv and confirmed the co-localization of OMVs, KTP, and scFv using super-resolution microscopy. The prepared OMV-KTP-scFv had high stability, effectively extended the plasma half-life of scFv, and could deliver scFv accurately to the proximal renal tubules. Furthermore, OMV-KTP-scFv also had good safety in vitro and in vivo, and no obvious biotoxicity was found during long-term in vivo administration. In addition, our results show that OMV-KTP-scFv significantly inhibited the expression of inflammatory factors in renal tubular cells of DN, reduced the infiltration of renal interstitial inflammatory cells, and alleviated renal tubular injury.

Conclusion

Our findings demonstrated that OMVs of Bacteroides fragilis targeting the kidney can deliver the IL-1β scFv to the renal tubulointerstitium and reduce the renal interstitial injury in DN by antagonizing local inflammation.
#894 Dynamic multi-omics and mechanistic modelling approach provides deeper insight into kidney fibrosis progression
Authors: Tuechler Nadine , Burtscher Mira Lea , Rodriguez-Cordoba Martin Garrido , Khan Muzamil Majid , Turei Denes , Kramann Rafael , Merten Christoph A , Rodriguez Julio Saez , Pepperkok Rainer
Published: May 2024

Background and Aims

Chronic kidney disease (CKD) affects more than 10% of the world's population and causes millions of deaths annually. Organ fibrosis is the main driver of CKD, leading to excessive accumulation of extracellular matrix (ECM). The presence of myofibroblasts correlates with disease progression. The pro-fibrotic responses of these cells, such as ECM production, are driven by the master regulator TGF-β. Despite progress in understanding the disease, there are no treatments available, and current diagnostic indicators neither facilitate early detection of CKD nor correlate with actual renal damage [1–4] Using human kidney-derived PDGFRβ+ mesenchymal cells we aim to provide time-resolved mechanistic insight into CKD progression.

Method

Our goal is to understand and model how these cells contribute to fibrosis by studying their kinetic response to TGF-β. Therefore, we use multiple omics measurements: transcriptomics, secretomics and phospho-/proteomics coupled with quantitative imaging of the ECM. For each time point, we quantified differential changes in omics and estimated the activities of transcription factors, kinases and phosphatases [5]. Furthermore, we used causal reasoning to draw mechanistic relationships between omics layers within and across time points.

Results

For validation, we focused on a set of transcription factors that also showed importance in the network context that considers several data modalities. Using knock-down experiments, we show the relevance of these transcription factors for the ECM deposition as well as the fibrotic response to TGF-β.

Conclusion

Taken together, by applying mechanistic modeling and the integration of multiple datasets, we are contributing to a better understanding of the factors and mechanisms driving kidney fibrosis. Furthermore, we will publish this dataset and thus provide a valuable resource for researchers in the field of CKD.
#1344 Molecular signatures of assembloids generated from stem cell derived nephron progenitors and ureteric bud cells as potential kidney organoid therapy
Authors: Woollard Kevin , Graneli Cecilia , Larsson Susanna , Petrillo Federica , Hong Xuechong , Holmgren Gustav , Vaithilingam Vijay , Söderberg Magnus , Sini Marcella , Stauske Michael , Wigge Leif , Hansen Pernille B L
Published: May 2024

Background and Aims

Novel therapies are needed to address the unmet clinical need of patients suffering from end stage kidney disease (ESKD) and cell therapy is an innovative strategy to deliver effective, curative treatment options to renal patients. There are several reports that have developed protocols to differentiate human pluripotent stem cells (hPSCs) into kidney-lineage progenitor derived organoid models and we have developed a robust and scalable method to produce kidney organoids.

Method

hPSCs were used to generate nephron progenitor cells (NPCs) and ureteric bud cells (UB) through previously described stem cell differentiation protocols. NPCs on day 9 of differentiation and UB on day 9 were combined for 2 days at 3:1 ratio respectively, to form ‘assembloids’ in-vitro and implanted in-vivo for 2 weeks. We used kidney capsule implantation in a NOD background mouse model and studied integration and phenotype using micro-CT and immunohistochemistry.

Results

RNA sequencing, flow cytometry and histology of NPCs, UB and assembloids in vitro shows broad representation of renal cell types by expression of markers representing several cell populations present in the developing nephron. We can currently show in-vitro molecular signatures of NPC derived organoids versus assembloids, with superiority of UB derived structures such as connecting tubules and intercalated cells. In-vivo histological examination of implanted assembloids showed maturation of human renal compartments such as collecting ducts, distal tubules as well as glomeruli-like structures. Micro-CT analysis showed integration with host and host derived endothelial vascularisation.

Conclusion

These observations demonstrate the use and differentiation potential of hPSCs and organoids in a pre-clinical setting towards more functional like kidney compartments by combining different progenitor populations. More work is needed evaluating these and other renal progenitor populations for future efforts to examine efficacy studies to develop regenerative therapies for ESKD.
#1322 VEGF therapy improves cardio-renal pathophysiology in a novel model of CKD-HFpEF
Authors: Chade Alejandro , Sitz Rhys , Mccarthy Elizabeth , Tharp Darla , Bidwell Gene , Eirin Alfonso
Published: May 2024

Background and Aims

Patients with chronic kidney disease (CKD) have a higher risk of developing heart failure with preserved ejection fraction (HFpEF). We developed a model of CKD-HFpEF and showed that renal-cardio pathophysiology is associated with decreased expression and availability of vascular endothelial growth factor in both organs. We showed that renal VEGF therapy improved renal function in our model. We hypothesize that cardiac VEGF therapy will improve cardiac function and will investigate whether cardiac protection in CKD also carries recovery of renal function.

Method

CKD and normal pigs (n = 4 each, 2 males/2 females) were studied for 14 weeks. In addition, CKD-HFpEF (n = 4, 2 males/2 females) were treated after 6 weeks of disease with a single intracoronary (IC) administration of VEGF attached to a drug-delivery vector (ELP-VEGF) that increases cardiac targeting, and effects quantified 8 weeks later. Renal (multi-detector CT) and cardiac (echocardiography, PV loops) morphology and function were quantified in vivo, microvascular (MV) density (3D micro-CT) ex vivo, and cardiac expression of VEGF was quantified by qPCR.

Results

Cardiac function, VEGF expression, and MV density were improved after IC ELP-VEGF therapy compared to placebo. Notably, renal hemodynamics (expressed as % change) were significantly improved compared to pre-treatment values and to time-matched untreated CKD-HFpEF pigs (Figure).

Conclusion

Our study suggests strong crosstalk between the heart and the kidney in a pre-clinical model of CKD-HFpEF. Renal and cardiac hemodynamics were significantly improved after cardiac VEGF therapy, conceptually supporting a cardio-renal axis in CKD and showing the extent of beneficial effects of a novel targeted intervention in a translational fashion.
#1451 Calcimimetics reduce the progression of high-phosphate diet-induced tubular damage
Authors: Walles Franziska , Richter Beatrice , Weingärtner Nina , Schmitz Jessica , Bräsen Jan Hinrich , Haffner Dieter , Leifheit-Nestler Maren
Published: May 2024

Background and Aims

During chronic kidney disease (CKD) progresses, there is an increased phosphate load and the concentration of the phosphaturic hormones PTH and FGF23 rises. In patients, phosphate and FGF23 are discussed as risk factors for CKD progression. We have recently shown that mice with high phosphate, PTH and FGF23 levels develop Stat3/Kim-1-mediated proximal tubule damage and tubulointerstitial fibrosis associated with increased MCP-1 expression and accumulation of macrophages. Calcimimetics lower PTH and FGF23 levels in hemodialysis patients and are thought to have both cardio- and nephroprotective effects. In a preclinical study, cinacalcet was shown to stabilize podocyte function in proteinuric mice. Therefore, we postulate that calcimimetics also have a positive effect on the progression of tubular damage in mice with high phosphate, PTH and FGF23 levels.

Method

For the induction of phosphaturic hormones with concomitant tubule damage, male C57BL/6 mice were fed a 2.0% high phosphate diet (HPD) and compared to animals on a 0.8% control phosphate diet (CPD). After four months, one HPD group was additionally treated with 1 mg/kg body weight/day etelcalcetide (KP-2326). Six months after the start of the trial, blood and urine samples as well as kidneys were taken for biochemical, histological and molecular biological examinations.

Results

KP-2326 treatment reduced HPD-induced PTH and FGF23 levels, but had no effect on increased phosphate excretion or elevated serum phosphate levels. Histologically, tubular damage was not as pronounced in the KP-2326-treated HPD animals as in the HPD group without therapy. The increased BUN levels caused by HPD and the albuminuria were significantly reduced by KP-2326. KP-2326 reduced HPD-mediated activation of Stat3 in proximal tubule cells and decreased Kim-1 synthesis at both mRNA and protein levels. Moreover, KP-2326 significantly reduced the mRNA expression of Ccl2 and the macrophage-specific marker Adgre1 compared to the untreated HPD group, which was histologically reflected in a lower accumulation of F4/80+ macrophages around the damaged tubules.

Conclusion

Treatment with KP-2326 was able to reduce the progression of HPD-induced tubule damage, at least in part due to the reduction in PTH and FGF23 levels.
#1116 Hyperuricemia worsens bacterial sepsis by suppressing neutrophil functions in CKD
Authors: LI Qiubo , Flora Kailey , Ehreiser Louisa , Steiger Stefanie
Published: May 2024

Background and Aims

Patients with kidney disease, especially those on dialysis, are more susceptible to infections such as peritonitis, sepsis, pneumonia, and are at a higher risk for infection-related mortality. Pathogenic mechanisms underlying the secondary immunodeficiency in kidney disease include gut dysbiosis and barrier dysfunction, persistent inflammation, immune paralysis due to increased levels of immunoregulatory metabolites (e.g. uric acid) and proteins (e.g. FGF23) [1]. Currently, it is unknown whether CKD-related hyperuricemia may contribute to the immune paralysis in this context. We hypothesized that hyperuricemia (HU) may aggravate the innate immune response to infection in CKD in mice.

Method

Mono- and polybacterial sepsis was induced by LPS injection or cecal ligation and puncture in Alb-creERT2;Glut9lox/lox mice with HU and/or CKD, and in Glut9lox/lox (healthy) control mice. After 24 hours, systemic inflammation was evaluated by measuring serum cytokine levels, immune cell activation and recruitment, and neutrophil extracellular trap release. Tissue injury in liver, heart, and kidney was assessed by performing RT-qPCR and immunohistochemistry. In addition, kidney function was determined by measuring the glomerular filtration rate (GFR). Additionally, mice were treated with urate-lowering therapy to reduce serum uric acid levels and the immune response and functional outcomes after sepsis is quantified.

Results

We found that both mono- and polybacterial sepsis caused systemic inflammation as indicated by an increased number of blood neutrophils (see Figure), neutrophil activation and pro-inflammatory cytokine levels as compared to the PBS-treated or sham-operated control groups in Glut9lox/lox healthy mice, respectively. Mice with sepsis also displayed a slightly worsened kidney function. Interestingly, HU significantly increased neutrophil numbers but decreased their activation status and the ability of neutrophils to form neutrophil extracellular traps in Alb-creERT2;Glut9lox/lox mice with sepsis as compared to the control groups, which was further aggravated in mice with CKD-related HU (CKD+HU). This impaired inflammatory response was partially reversible by lowering serum uric acid with febuxostat.

Conclusion

Our results identify hyperuricemia related or unrelated to kidney disease as immune regulator in bacterial infection by suppressing neutrophil functions in mice. Specifically targeting uric acid may help to overcome the secondary immunodeficiency related to kidney disease during infection but enhances sterile inflammation [2].
#2036 Mitochondrial copper overload promotes renal fibrosis via inhibiting pyruvate dehydrogenase activity
Authors: Zhu Saiya , Yu Chen
Published: May 2024

Background and Aims

Copper is a trace element essential for numerous biological activities, whereas the mitochondria serve as both major sites of intracellular copper utilization and copper reservoir. Pyruvate dehydrogenase complex (PDHC) is a rate-limiting enzyme of glucose oxidation in mitochondrial matrix, converting pyruvate into acetyl-CoA and linking glycolysis to tricarboxylic acid (TCA) cycle. Dihydrolipoamide acetyltransferase (DLAT), the E2 component of the PDHC, requires lipoylation for enzymatic function and exhibits a high affinity for copper within its lipoyl moiety. Here, we investigated the impact of mitochondrial copper overload on the tricarboxylic acid cycle and renal senescence and fibrosis.

Method

Molecular dynamics simulation was used to explore the effect of copper ions on lipoylated DLAT protein. ICP-MS was used to detect copper content in mitochondria. Western blotting was used to detect the level of lipoylated DLAT dimer. Enzyme biopsy test kit, electron microscopy, mitoSOX Red staining and ATP content detection were used to evaluate mitochondrial function. Detect Collagen I, α-smooth muscle actin (α-SMA) expression levels and Masson staining to explore renal fibrosis. To reduce mitochondrial copper level, we used lentivirus to downregulate CRT1 expression or copper chelator tetrathiomolybdate in renal tubular epithelial cells (NRK-52E), and used CTR1 knockdown transgenic mice or tetrathiomolybdate in vivo.

Results

We found that copper ion levels are significantly elevated in the mitochondria in fibrotic kidney tissues, which are accompanied by reduced pyruvate dehydrogenase (PDH) activity, mitochondrial dysfunction, cellular senescence and renal fibrosis. Conversely, lowering mitochondrial copper levels through knocking-down of copper transporter 1 or treatment with the copper chelator tetrathiomolybdate effectively restore PDH enzyme activity, improve mitochondrial function, and mitigate cellular senescence and renal fibrosis. Mechanically, we found mitochondrial copper binds directly to lipoylated dihydrolipoamide acetyltransferase (DLAT), thereby changing the interaction between protein subunits, inducing lipoylated DLAT protein dimerization, and ultimately inhibiting PDH enzyme activity.

Conclusion

Our study indicates that mitochondrial copper overload could inhibit PDH activity, subsequently leading to mitochondrial dysfunction, cellular senescence and renal fibrosis. Reducing mitochondrial copper overload might therefore serve as a strategy to rescue renal fibrosis.
#1841 Trimethylamine N-oxide (TMAO) induces the formation of endothelial extracellular vesicles
Authors: Azevedo Carolina Amaral Bueno , Da Cunha Regiane Stafim , de Almeida Guilherme Miniskiskosky , de Souza Ingrid Larissa Melo , Stinghen Andréa E M
Published: May 2024

Background and Aims

Endothelial dysfunction caused by the accumulation of uremic toxins is an important contributor to the development of cardiovascular disease in patients with chronic kidney disease (CKD). The uremic toxin trimethylamine n-oxide (TMAO) is associated with oxidative stress, vascular calcification, and inflammation, triggering the release of several proinflammatory molecules and Extracellular Vesicles (EVs). Clinical studies have shown that patients with CKD have high levels of circulating EVs, however, their role is still poorly understood. In this dysfunctional scenario, EVs can be used as damage biomarkers for CKD, as they carry information from their cells of origin. Here, we aim to elucidate the formation of EVs in endothelial cells exposed to TMAO.

Method

Human endothelial cells (EA.hy926, ATCC CRL-2922) were exposed for 24 h with TMAO at uremic concentrations (7.49 mg/L). EVs were isolated by differential ultracentrifugation. Protein concentration was analyzed by Pierce™ BCA Protein Assay Kit, and particle size and particle concentration were analyzed by NanoParticle Tracking Analysis (NTA), Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM). EVs were stained with calcein and their internalization in endothelial cells was analyzed with Fluorescence Confocal Microscopy.

Results

TMAO treatment at uremic concentration induced the formation of EVs with a size of 202.8 ± 3.1 nm (image 1B) and 1.09 × 109 ± 2.68 × 107 particles/mL and a total protein concentration of 88.57 µg/mL. The morphological features of EVs are shown in images 1C-1F. TMAO-induced EVs were incorporated by endothelial cells, being dispersed in the cytoplasm or perinuclear regions (images 1G and end 1H).

Conclusion

TMAO was able to induce the formation of EVs in endothelial cells, with characteristics morphological features. When compared to control EVs (image 1A), TMAO-EVs have a more heterogeneous size, which indicate a change in the size pattern, and thus the nature of the EVs induced by TMAO. TMAO-EVs were able to be internalized by human endothelial cells. This uptake can be closely related to the effects of EVs in endothelial cells, but more experiments need to be performed. Taken together, these data could contribute to understanding how the formation and uptake of TMAO-EVs by the endothelium occurs, relating their effects to the cardiovascular complications of CKD.
#991 Estimated small dense low-density lipoprotein-cholesterol and the risk of renal and cardiovascular outcomes in diabetic kidney disease
Authors: Yang Qing , Liu Fang
Published: May 2024

Background and Aims

This study aimed to investigate the correlations between estimated small dense low-density lipoprotein-cholesterol (esd-LDL-c) and the development of end-stage renal disease (ESRD), cardiovascular mortality, and all-cause mortality in individuals with diabetic kidney disease (DKD) or diabetes mellitus (DM) concomitant chronic kidney disease (CKD).

Method

We analyzed the data from a biopsy-proven DKD cohort conducted at West China Hospital of Sichuan University between 2009 and 2021 (the DKD cohort) and the participants with DM and CKD in the NHANES 2011-2014 (the NHANES DM-CKD cohort). Cox regression analysis was used to estimate associations between esd-LDL-c and the incidence of ESRD, cardiovascular mortality, and all-cause mortality.

Results

There were 175 ESRD events among 338 participants in the DKD cohort. Patients were divided into three groups based on esd-LDL-c tertiles (T1<33.7 mg/dL, T2≥33.7 mg/dL to <45.9 mg/dL, T3≥45.9 mg/dL). The highest tertile of esd-LDL-c was independently associated with ESRD (adjusted HR 2.016, 95% CI 1.144–3.554, P = 0.015). There were 99 death (39 cardiovascular) among 293 participants in the NHANES DM-CKD cohort. Participants were classified into three groups in line with the tertile values of esd-LDL-c in the DKD cohort. The highest tertile of esd-LDL-c was independently associated with cardiovascular mortality (adjusted HR 2.84, 95% CI 1.02–7.97, P = 0.047) and all-cause mortality (adjusted HR 2.18, 95% CI 1.08–4.4, P = 0.029).

Conclusion

Higher esd-LDL-c increased the risk of ESRD in people with DKD and the risk of cardiovascular and all-cause mortality among those with DM-CKD.
#1427 Comparison of METS-IR and HOMA-IR for predicting new-onset CKD in middle-aged and older adults
Authors: Lee Jung Eun , Kwon Yu-Jin , Park Hyeong Cheon
Published: May 2024

Background and Aims

Chronic kidney disease (CKD) has emerged as a mounting public health issue worldwide; therefore, prompt identification and prevention are imperative in mitigating CKD-associated complications and mortality rate. We aimed to compare the predictive powers of the homeostatic model assessment for insulin resistance (HOMA-IR) and the metabolic score for insulin resistance (METS-IR) for CKD incidence in middle-aged and older adults.

Method

This study used longitudinal prospective cohort data from the Korean Genome and Epidemiology Study. A total of 10,030 participants, aged 40–69 years, residing in the Ansung or Ansan regions of the Republic of Korea, were recruited between 2001 and 2002 through a two-stage cluster sampling method. We compared the predictive powers of METS-IR and HOMA-IR for CKD prevalence and incidence, respectively. CKD prevalence was measured by the area under the receiver operating characteristic (ROC) curve (AUC), and the indices’ predictive performance for CKD incidence were assessed using Harrell's concordance index and time-dependent ROC curve analysis.

Results

A total of 9261 adults aged 40–69 years at baseline and 8243 adults without CKD were included in this study. The AUCs and 95% confidence intervals (CIs) of HOMA-IR and METS-IR for CKD prevalence at baseline were 0.577 (0.537–0.618) and 0.599 (0.560–0.637), respectively, with no significant difference (p = 0.337). The Heagerty's integrated AUC for METS-IR in predicting CKD incidence was 0.772 (95% CI 0.750–0.799), which was significantly higher than that of HOMA-IR (0.767 [95% CI 0.742–0.791], p = 0.015).

Conclusion

METS-IR surpassed HOMA-IR in predicting CKD incidence and was as effective as HOMA-IR in predicting CKD prevalence. This implies that METS-IR could be a valuable indicator for early detection and prevention of CKD among Korean adults.
#913 Impact of retinal photography-based deep learning system on risk stratification for chronic kidney disease progression
Authors: Park Jung Tak , Joo Young Su , Rim Tyler Hyungtaek , Han Seung Hyeok , Yoo Tae-Hyun , Kang Shin-Wook
Published: May 2024

Background and Aims

We had previously developed a deep-learning-based risk evaluation system from retinal photographs, Reti-CKD, for stratifying chronic kidney (CKD) development risk in kidney function preserved people. This study aims to evaluate whether Reti-CKD can improve risk assessment of kidney disease progression in diabetic patients with prevalent CKD.

Method

Total of 5348 diabetic patients from two tertiary hospitals in Korea were evaluated. Patients with estimated glomerular filtration rate (eGFR) <90 ml/min/1.73 m2 or albuminuria were included. Those with missing data for retinal photograph, serum creatinine, or albuminuria were excluded. Patients were categorized into low-risk, moderate-risk, and high-risk groups according to the KDIGO criteria for prognosis of CKD. The KDIGO groups were additionally dichotomized based on Reti-CKD score (Reti-CKD <20 and ≥20). CKD progression was compared between the categories using Cox regression models. Primary outcome was CKD progression, defined as incremental progression to a higher NKF-KDOQI CKD stage.

Results

The mean age of the patients was 62.4 ± 11.4 years and 60.6% were male. Mean eGFR was 86.6 ± 15.3 mL/min per 1.73 m2 and albuminuria was present in 46.9%. During a median follow-up of 5.0 (interquartile range, 2.5-7.8) years, primary outcome developed in 1379 (25.8%) patients. The primary outcome incidence rate gradually increased with higher KDIGO and Reti-CKD combined risk categories. The risk for CKD progression progressively increased in KDIG moderate-risk and high-risk groups compared to low-risk. When Reti-CKD was incorporated to the KDIGO category, significant stratification of CKD progression risk was noted in the KDIGO low-risk and moderate-risk groups (Table and Figure). Additionally, the combination of KDIGO and Reti-CKD classification showed better discrimination power compared to the KDIGO only classification (delta c-statistics, 0.03; 95% CI 0.02 to 0.040).

Conclusion

Retinal photography-based deep learning system (Reti-CKD) further stratifies the risk of CKD progression and improves predictability in diabetic patients with reduced renal function.
#1037 Urinary marinobufagenin reflects the severity of renal disease in non-advanced CKD: a pilot study
Authors: Zicarelli Mariateresa , D'agostino Mario , Tripodi Loredana , Musolino Michela , Cianfrone Paola , Andreucci Michele , Coppolino Giuseppe , Bolignano Davide
Published: May 2024

Background and Aims

The identification of new biomolecules involved in the pathogenesis of chronic kidney disease (CKD) which may improve clinical understanding remains a research priority. Marinobufagenin (MBG) is an endogenous cardiotonic steroid endowed with natriuretic and vasoactive properties, which altered levels trigger fibrosis of various organs, including the kidney. The kidney plays a central role in regulating the systemic MBG balance through its urinary excretion (uMBG) but the impact of a reduced clearance due to CKD remains unknown. In this pilot study, we analyzed the clinical and diagnostic significance of uMBG in a cohort of CKD patients with mild-to-moderate CKD (stage 2-4)

Method

uMBG was measured in 108 CKD patients (mean age 71.6 ± 10 yrs, 70.4% male; mean eGFR 40.54 ± 17 mL/min/1.73 m2) together with a series of clinical, anthropometric, laboratory and instrumental parameters to identify clinical predictors in this cohort. Additionally, uMBG was measured in 25 healthy matched subjects.

Results

CKD patients displayed lower uMBG values as compared with controls (0.37 [IQR 0.25-0.45] vs. 0.64 [0.46-0.78] nmol/L; p = 0.004). Clinical, independent predictors of uMBG in our study cohort were eGFR (β = 0.248; p = 0.01), the use of statins (β=-0.326; p = 0.001), diabetes (β = 0.243; p = 0.009) and urinary sodium (β = 0.204; p = 0.01). At logistic regression analysis, higher uMBG levels were associated with a lower probability of having an eGFR ≤30 mL/min (OR 0.868; 95% CI 0.798-0.986; p = 0.03). At ROC analyses, uMBG displayed a good diagnostic capacity in identifying patients with more advanced CKD (AUC 0.675; 95% CI 0.578 to 0.762; p = 0.002; Fig. 1).

Conclusion

Conclusions: Overall, CKD patients display a reduced uMBG excretion which parallels the severity of renal clearance impairment. Sodium intake, diabetes and the assumption of statins may modulate such relationship. Additional studies are needed to confirm the diagnostic usefulness and biological meaning of measuring uMBG as a way to assess CKD severity.