bluuebunny/crossref_metadata_2025 huggingface dataset:
SO003LIFE-LONG NLRP3 INFLAMMASOME-MEDIATED SYSTEMIC INFLAMMATION ASSOCIATES WITH CARDIOVASCULAR MORTALITY: A GENETIC ASSOCIATION STUDY OF >500,000 INDIVIDUALS
Authors: Schunk Stefan , Kleber Marcus E , Maerz Winfried , Zewinger Stephen , Isabella Jaumann , Schmit David , Fliser Danilo , Ulrich Laufs , Speer Thimoteus
Published: June 2020

Background and Aims

Chronic kidney disease (CKD) represents one of the strongest cardiovascular risk factors. Recently, we have shown that activation of the NOD-like receptor protein-3 (NLRP3) inflammasome mediates progression of kidney injury and CKD-associated vascular disease (Zewinger et al. Nat Immunol 2013). Components of the NLRP3 inflammasome pathway such as interleukin-1β (IL-1β) can therapeutically be targeted. Associations of genetically determined life-long inflammasome-mediated systemic inflammation with CVD and mortality in humans are unknown.

Method

We explored the association of genetic NLRP3 variants with prevalent CVD and cardiovascular mortality in 3,061 patients enrolled in the LURIC study undergoing coronary angiography in a gene-centric approach. Functional relevance of the rs10754555 NLRP3 variant was studied in freshly isolated human monocytes. Findings were validated in 39,755 participants from eight independent studies (CV risk populations) as well as in 483,258 participants of the UKBiobank study (general population).

Results

Genetic analyses identified the highly prevalent (MAF 39.9%) intronic NLRP3 variant rs10754555 to affect NLRP3 gene expression. rs10754555 carriers showed significantly higher C-reactive protein and serum amyloid A plasma levels. Expression of NLRP3 mRNA and inflammasome-dependent effector responses of isolated human monocytes from rs10754555 carriers were significantly higher as compared to non-carriers. In homozygous rs10754555 carriers, the prevalence of coronary artery disease (CAD) was significantly higher as compared to non-carriers with a significant interaction between rs10754555 and age in LURIC and in UKBiobank. Importantly, in LURIC and in UKBiobank, homozygous rs10754555 carriers had significantly higher risk for cardiovascular mortality during follow-up (HR 1.37, 95%-CI 1.08-1.74 and HR 1.13, 95%-CI 1.02-1.25, respectively). Consistently, rs10754555 was associated with higher cardiovascular mortality (HR 1.11, 95%-CI 1.05-1.16; P<0.001) in an additive model in patients with prevalent CAD.

Conclusion

The NLRP3 intronic variant rs10754555 is associated with increased systemic inflammation, inflammasome activation, prevalent CAD and mortality. This study provides evidence for a substantial role of life-long, genetically-driven systemic inflammation in cardiovascular disease and highlights the NLRP3 inflammasome as a therapeutic target in the general population and particular in patients with CKD.
SO009MORTALITY AND HOSPITALIZATION IN A LARGE INTERNATIONAL PERITONEAL DIALYSIS INSTITUTION DURING 2018
Authors: Marrón Belén , Pearce Suzanne , Wollheim Charlotta , Lucas Carlos , Torok Marietta , Munteanu Dan , Roesch Michael , Ostrowski Janusz , Kochman Pawel , Orosz Attila , Pérez Daniel , Pacheco Alejandro , Macário Fernando
Published: June 2020

Background and Aims

With the exception of some national registries, data referred to mortality or hospitalization within a single large international peritoneal dialysis (PD) institution are seldom reported.

To study all-cause mortality, transplantation rate, hospitalizations and peritonitis rates in our large PD program during 2018.

Method

Observational, prospective registry in 8 countries. The following variables were tracked: crude mortality rate and causes, hospitalization variables (nº of hospitalization days per patient; nº of hospitalization episodes per patient; nº of days per hospitalization episode; causes of hospitalization), peritonitis rate (episodes/year at risk and patient months at risk to a peritonitis episode) and transplantation rate.

Results

By the end of December 2018, 1207 pt. were treated (11 countries) but only 8 countries submitted data. Evaluated population as “patients treated at risk during the year”: AR (319.5), RO (173.5), DE (137), HU (103), PL (97), UR (69.5), CL (27), KZ (7). Crude mortality rate was 13.1%, same if first 90 days on therapy were excluded. Lowest mortality was seen in HU (9.9%) and highest in DE (19.3%). Causes of death: cardiac 32%, all type infections 22% [Sepsis 78%, PD related 11% (as 0.7% of total mortality), pulmonary 3.7%, others 7.4%], vascular 10%, gastrointestinal 3.3%, unknown 10.7% (highest in DE, 23%), other known causes 21.5%. Hospitalization rates: 0.55 episodes/per patient-year and 7.6 days of hospitalization per patient-year. Nº of days per hospitalization episode was 13.7. Causes of hospitalization: PD related 38%, cardiovascular 17%, non-PD infection sepsis 10.7% (higher in LA, 16.6%), vascular access 2.1%, unknown 4.5%, others 23.3%. Global peritonitis rate was 0.18 episodes/pt-year at risk (1 episode every 66 m.). However, large differences were seen among countries. Transplantation rate was 6.5% (much higher in UR). PD was withdrawal in 35% of pt. Country specific data have been evaluated but are not shown here.

Conclusion

The use of a common registry in our institution increases quality and allows homogeneous comparisons across countries that if promptly addressed may increase patients’ outcomes. Our series may bring light into the PD community as one of the ever largest tracked in a single institution.
SO010URINARY LITHOGENIC RISK PROFILE IN ADPKD PATIENTS TREATED WITH TOLVAPTAN
Authors: Bargagli Matteo , Dhayat Nasser A , Anderegg Manuel , Semmo Mariam , Huynh-Do Uyen , Vogt Bruno , Ferraro Pietro Manuel , Fuster Daniel Guido
Published: June 2020

Background and Aims

Nephrolithiasis is a common health problem in autosomal dominant polycystic kidney disease (ADPKD) and significantly contributes to patient morbidity. In observational studies, prevalence rates of up to 36% have been reported. Kidney stones of ADPKD patients are typically composed of uric acid (UA) or calcium oxalate (CaOx), and hypocitraturia and low urinary pH have been reported as the main prolithogenic abnormalities. Recently, Tolvaptan has been introduced for the treatment of ADPKD, but its impact on the lithogenic risk profile in ADPKD patients remains unknown.

Method

We conducted a retrospective analysis of patients enrolled in the Bern ADPKD registry, an observational cohort study. Inclusion criteria were age ≥ 18 years, clinical diagnosis of ADPKD, and informed consent. The main exclusion criterion was need for renal replacement therapy. 24-h urine analyses were performed at baseline and then at yearly follow-ups. Relative supersaturation ratios (RSS) for CaOx, calcium phoshate (CaP) and UA were calculated with EQUIL2. Univariate and multivariate mixed-effects linear regression models, adjusted for age, sex, BMI, eGFR and endogenous acid production, estimated by net acid excretion, were used to assess the impact of Tolvaptan treatment on urinary composition.

Results

38 patients received Tolvaptan treatment (39.5% females) and were included in the analysis. Six patients (15.8%) had a history of symptomatic stone events. In multivariate analysis, Tolvaptan treatment was significantly associated with reductions of CaOx, CaP and UA RSS (p < 0.01) and increased urinary citrate (p = 0.015) and calcium (p < 0.01) excretion. In contrast, Tolvaptan treatment was not associated with alterations in urinary oxalate excretion or urinary pH.

Conclusion

Tolvaptan significantly reduces RSS for CaOx, CaP and UA. Future studies are needed to assess the impact of Tolvaptan treatment on stone recurrence in ADPKD patients.
SO011OXALATE-DEGRADING ACTIVITY IN FECAL MICROBIOTA ASSOCIATED WITH BLOOD LIPID PROFILE IN DIALYSIS PATIENTS
Authors: Stepanova Natalia , Tolstanova Ganna , Akulenko Iryna , Savchenko Olena , Lebid Larysa , Skovorodka Marharyta , Kolesnyk Mykola
Published: June 2020

Background and Aims

Cardiovascular disease (CVD) remains the leading cause of morbidity and death in end-stage renal disease (ESRD) patients. Thus, the accumulation of oxalate due to ESRD can increase the risk of CVD. Also, the ability of fecal oxalate-degrading activity (ODA) to reduce plasma oxalate levels has been discussed. On the other hand, despite a key role of atherogenic dyslipidemia in the development of CVD, only a few studies have shown a potential role of microbiota in the regulation of blood lipid profiles in the general population. However, at present, there is a general lack of research on this topic in dialysis patients.  

The present study aimed to investigate the association between oxalate-degrading activity (ODA) in fecal microbiota and blood lipid profiles in ESRD patients.

Method

We represented the data of a cross-sectional pilot study examining ODA in fecal microbiota, plasma oxalate concentration (POx) and blood lipid profile markers in 32 ESRD patients. Among the patients, there were 21 hemodialysis (HD) patients and 11 peritoneal dialysis (PD) patients. The average age of the patients was 52.5 [39; 65] years.

The redoximetric titration with KMnO4 was adopted to evaluate total ODA in fecal microbiota. The results were expressed in % oxalate degradation per 0.01 g of feces. The blood lipid spectrum was determined in all patients: total cholesterol level (TC), high (HDL), low (LDL) and very low (VLDL) density cholesterol, triglycerides (TG) and atherogenic index of plasma (AIP).

The median (Me) and interquartile ranges [Q25; Q75] were calculated using the nonparametric Kruskal-Wallis test. The Spearman test was used for the correlation analysis. Chi-square tests were used for comparison of 2 proportions. All statistical analyses were performed using MedCalc.

Results

Dyslipidemia defined as an increase in atherogenic lipoprotein fractions and inhibition of HDL cholesterol was identified in 13/32 (40.6%) ESRD patients. Negative ODA in fecal microbiota (≤ 0 % /0.01 g) was observed in 14/32 (43.7%) patients. Among them, there were 5/21 (23.8%) HD patients and 7/11 (63.6%) PD patients (χ2=3.9, p=0.04).

Significantly lower ODA in fecal microbiota was observed in the patients with atherogenic dyslipidemia in comparison with dyslipidemia-free patients (-5.0 [-8.7; 3.7] vs 3.0 [0.5; 9] %/0.01 g of feces, p=0.02) (Fig. 1). Less ODA in fecal microbiota was, higher levels of TG (r=-0.5, p=0.004) (Fig. 2), VLDL (r=-0.34, p=0.05) (Fig. 3) and, accordingly, AIP (r=-0.38, p=0.03) (Fig. 4) occurred.

Conclusion

The results of our study have provided preliminary evidence on the fact that a decrease in total ODA in fecal microbiota is associated with atherogenic dyslipidemia. Further studies are needed to determine the role of fecal ODA in the formation of dyslipidemia.
SO012RENOPROTECTIVE EFFECTS OF FEBUXOSTAT AND ALLOPURINOL IN PATIENTS WITH HYPERURICEMIA AND CHRONIC KIDNEY DISEASES: A META-ANALYSIS
Authors: Edding Sherida , Cabral Brian Michael , Cating-Cabral Monica Therese
Published: June 2020

Background and Aims

Hyperuricemia is associated with rapid deterioration of renal function in patients with chronic kidney disease (CKD). The two most common urate-lowering drugs available in the market are allopurinol and febuxostat. Randomized controlled trials (RTCs) have shown that the individual drugs have potential to slow down progression of renal function in patients with chronic kidney disease (CKD) and hyperuricemia. However, it is unclear which drug is more effective because of insufficient direct comparison between the two. Hence our study aims to perform a meta-analysis of RCTs to assess the renoprotective and urate-lowering effects between the two drugs in patients with CKD and hyperuricemia.

Method

A comprehensive literature search of randomized controlled trials using PubMed was performed with the following search terms: febuxostat, allopurinol, chronic kidney disease, renoprotection. Four prospective RCTs were selected and analyzed using Cochrane Revman v5.3. Outcomes assessed were change in serum creatinine, estimated glomerular filtration rate (eGFR), proteinuria and serum uric acid levels from baseline to 3 months post-initiation of therapy.

Results

Four relevant trials comprising of 486 patients were selected - 247 patients treated with febuxostat and 239 patients with allopurinol. No significant differences were found in the changes in serum creatinine (mean difference -0.04; CI -0.15, 0.07; P = 0.51) and eGFR (mean difference 1.57; CI -0.83, 3.97; P = 0.20) from baseline to 3 months between the febuxostat and allopurinol group. Decrease in proteinuria was significantly observed more in the febuxostat group (mean difference -50.13; CI -90.54; -9.71, P = 0.02). Similarly, serum uric acid levels were significantly more reduced in the febuxostat group (mean difference -1.11; CI -1.53, -0.68, P < 0.00001).

Conclusion

Our study showed that febuxostat is non-inferior in terms of delaying renal function decline (as measured by eGFR) but it offers a better anti-proteinuric as well as a urate-lowering effect. However, more studies are needed to assess the efficacy of febuxostat across the spectrum of chronic kidney disease, including those requiring hemodialysis.
SO013CRUCIAL ROLE OF SERUM RESPONSE FACTOR IN EPITHELIAL-MESENCHYMAL TRANSITION OF RENAL TUBULAR EPITHELIAL CELLS IN HYPERUREICEMIC NEPHROPATHY
Authors: Zhao Long , Xu Yan
Published: June 2020

Background and Aims

To investigate the role of serum response factor (SRF) in epithelial-mesenchymal transition (EMT) of renal tubular epithelial cells (TECs) in hyperuricemic nephropathy (HN).

Method

The expression of SRF, epithelial markers (E-cadherin and ZO-1) and mesenchymal markers (fibronectin, α-SMA, FSP-1) was examined in rat renal tubular epithelial cells (NRK-52E cells) or renal medulla tissues following uric acid (UA). SRF was upregulated by SRF plasmids and downregulated by CCG-1423(a small molecule inhibitor of SRF) to investigate how SRF influenced EMT in TECs of HN. Oxonic acid (OA) was used to generate HN in rats.

Results

Conclusion

Together, increased SRF activity promotes EMT and dysfunction of TECs in HN. Targeting SRF by small molecule inhibitor may be an attractive therapeutic strategy for HN.
SO022EVALUATION OF GLOMERULAR HEMODYNAMIC CHANGES BY SGLT2 INHIBITION IN TYPE 2 DIABETIC RATS USING IN VIVO IMAGING TECHNIQUES
Authors: Wada Yoshihisa , KIDOKORO KENGO , Tokuyama Atsuyuki , Kondo Megumi , Kadoya Hiroyuki , Nagasu Hajime , Sasaki Tamaki , Kashihara Naoki
Published: June 2020

Background and Aims

In recent clinical trials, the SGLT2 inhibitor (SGLT2i) slowed the progression of kidney disease compared with the placebo in patients with type 2 diabetes. Improvement of glomerular hyperfiltration via tubuloglomerular feedback (TGF) is considered to be one of the possible pathways for renal protection with SGLT2 inhibition (SGLT2i) in diabetic kidney disease (DKD). We have successfully developed the novel method to measure single-nephron GFR (SNGFR) in mice using multiphoton laser microscopy and demonstrated that the adenosine/adenosine A1 receptor (A1aR) pathway plays a pivotal role in the TGF mechanism in the type 1 diabetic model, Akita mice (Kengo Kidokoro, David Z. I. Cherney et al. Circulation. 2019). It has been suggested that the mechanism of improvement effects in glomerular hyperfiltration by SGLT2i is different in type 1 diabetes and type 2 diabetes. However, the detailed regulatory mechanism of GFR by SGLT2i is not fully understood in type 2 diabetes. This study aims to clarify the effects of SGLT2i on glomerular hemodynamics in type 2 diabetic rats.

Method

Zucker lean (ZL) rats and Zucker diabetic fatty (ZDF) rats were used. In the first experiment, SNGFR and diameters of glomerular afferent/efferent arterioles were measured in both groups. Next, we examined the change of SNGFR and diameters of glomerular afferent/efferent arterioles, as well as urinary excretions of glucose and sodium in ZDF after a single-dose administration of SGLT2i (luseogliflozin; 10mg/kg, gavage) for 120 minutes, which generated the following three groups: SGLT2i group, SGLT2i + adenosine A1 receptor (A1aR) antagonist (8-cyclopentyl-1,3-dipropylxanthine, 1mg/kg) group, and insulin group.

Results

SNGFR in the ZDF group was significantly higher than in the ZL group. The diameter of the afferent arteriole and efferent arteriole was also wider in ZDF rats than in ZL rats. The SNGFR and diameter of the afferent arteriole were significantly decreased after a single-dose administration of SGLT2i in ZDF. However, there was no significant diameter change in the efferent arteriole. Moreover, a decrease of SNGFR was not observed in the A1aR antagonist group after SGLT2i administration. Urinary excretions of glucose and sodium showed a similar pattern in the SGLT2i and SGLT2i+ A1aR antagonist groups.

Conclusion

The adenosine/A1aR pathway plays an important role in the regulation of the tonus of the afferent arteriole and is involved in the suppression of glomerular hyperfiltration by SGLT2 inhibition in type 2 diabetes.
SO024THE GPR120 AGONIST TUG-891 AMELIORATES KIDNEY FIBROSIS AND INFLAMMATION IN DIABETIC NEPHROPATHY
Authors: Wei Tiantian , Ma Liang , Fu Ping
Published: June 2020

Background and Aims

ω3-Fatty acids (ω3FAs) attenuated inflammation, glomerulosclerosis and albuminuria in most experimental studies of diabetic nephropathy (DN). GPR120 has been identified as a first receptor for ω3FAs. Compared to ω3FAs, TUG-891 is a highly potent and selective agonist for GPR120. In this study, we examined the protective effects of GPR120 agonist TUG-891 in DN and investigated the possible mechanisms.

Method

Expression of GPR120 was detected in human renal biopsy tissue obtained from patients with early or advanced DN and in normal renal tissues. Effects of TUG-891 on the development of DN were investigated in male C57BLKS/J db/db mice and murine podocytes (MPC5). Expression of collagen IV, fibronectin, αSMA, TGF-β/smad2/3, IL-6, GPR120/β-arrestin2/TAK1 binding protein-1 and downstream pathways were measured.

Results

The expression of GPR120 was negatively correlated with the progression of DN. IF stainings showed that GPR120 was mainly expressed in podocytes of the glomerulus by co-localization of a special marker nephrin. In db/db mice, oral administration of TUG-891 significantly reduced urinary albumin excretion, improved podocyte injury and reduced collagen deposition in glomerulus. Meanwhile, TUG-891 inhibited the expression of fibronectin, collagen IV, α-SMA, TGF-β1 and IL-6, as well as down-regulated phosphorylation of Smad3 and STAT3 to alleviate the glomerulosclerosis. Mechanistically, TUG-891 effectively up-regulated the GPR120 expression in kidneys of db/db mice and HG-stimulated podocytes. TUG-891 also suppressed TAB1 expression and the phosphorylation of TAK1, IKKβ, NF-κB, JNK and p38 MAPK signals. 

Conclusion

In summary, our result highlighted that TUG-891 ameliorated kidney fibrosis and inflammation by activating the intracellular GPR120 signaling pathway.
SO035EFFECT OF DIETARY SALT REDUCTION ON BLOOD PRESSURE IN KIDNEY TRANSPLANT PATIENTS: A RANDOMISED CONTROLLED TRIAL
Authors: Ross Louise , Suckling Rebecca , He Fengjun , Dockrell Mark , Bailey Thomas , Swift Pauline
Published: June 2020

Background and Aims

Cardiovascular morbidity and mortality are increased in kidney transplant patients. High blood pressure (BP) contributes significantly to this risk and is associated with shortened allograft survival. Dietary salt reduction is widely recommended as a strategy to lower BP in the general population and in chronic kidney disease. Due to a lack of evidence there is currently no consensus on dietary salt restriction in kidney transplant patients. The primary aim of the study was to examine the impact of reduced dietary salt intake on BP in kidney transplant patients.

Method

Sixty stable kidney transplant patients, ≥ 6-months post-transplantation, with BP ≥120/80 mmHg, and sodium intake ≥80 mmol/24hrs, were randomised in this parallel-designed study to receive either a regular-salt diet (target 150 mmol/24hr) or a low-salt diet (target 80 mmol/24hr) for 8-weeks. The primary outcome measure was systolic and diastolic BP. Secondary outcome measures included 24-hour ambulatory BP (ABP) and proteinuria. Dietary salt intake was assessed by 48-hour urinary sodium excretion.

Results

At baseline, patients (72% men) were 56±11 years with estimated glomerular filtration rate (eGFR) 53±18 mL/min/1.73m2. Mean urinary sodium was 128±42 mmol/24hr, mean systolic BP was 132±12 mmHg, and mean diastolic BP was 77±10 mmHg. At the end of the intervention period sodium excretion was significantly lower in the low-salt group compared with the regular-salt group (90±37 vs. 132±51 mmol/24hr; adjusted mean difference, -36 [95% CI, -59 to -14] mmol/24hr; P=0.002). We found no difference in systolic BP (adjusted mean difference, -2 [95% CI, -12 to 9] mmHg; P=0.750), diastolic BP (adjusted mean difference, 0 [95% CI, -4 to 4] mmHg; P=0.887), 24-hour systolic ABP (adjusted mean difference, -3 [95% CI, -9 to 2] mmHg; P=0.213) or 24-hour diastolic ABP (adjusted mean difference, -2 [95% CI, -5 to 1] mmHg; P=0.267). There was no significant effect on proteinuria or eGFR.

Conclusion

In this study baseline urinary sodium was lower than expected and baseline BP was well controlled. Reducing dietary salt by 2g/day did not have a significant effect on office blood pressure readings.
SO039BETA3-ADRENORECEPTOR AS A NEW PLAYER IN SYMPATHETIC REGULATION OF THE ACID-BASE HOMEOSTASIS IN THE KIDNEY
Authors: Milano Serena , Gerbino Andrea , Carmosino Monica , Svelto Maria , Procino Giuseppe
Published: June 2020

Background and Aims

Sympathetic nervous system has a key role in the regulation of renal function. We previously showed that, in mouse, the β3-adrenoreceptor (β3-AR) localizes in most of the nephron segments and its selective agonism promotes a potent antidiuretic effect. Here, we evaluate the expression of β3-AR in kidney intercalated cells (ICs) which are associated with the regulation of acid-base homeostasis in distal segments of the kidney tubule. The aim of this study is to investigate whether the β3-AR might play a role in the acid-base homeostasis operated by the kidney.

Method

The β3-AR expression in mouse kidney ICs was investigated by confocal microscopy. Wild type (wt) and β3-AR knock-out (ko) mice were used to study the role of β3-AR in the renal acid-base homeostasis. Mouse urine were collected using metabolic cages and pH was measured. Immunofluorescence and Western blotting experiments were performed to evaluate the localization and the abundance of renal H+-ATPase in wt and β3-AR ko mice. Kidney cells expressing human β3-AR (M1-β3-AR) and endogenous H+-ATPase were used to investigate the possible effects of β3-AR stimulation on the activity/localization of H+-ATPase. Live imaging experiments using the pH-sensitive dye BCECF were carried out to determine intracellular pH and assess H+-ATPase activity.  Immunofluorescence experiments were performed to reveal the effects of β3-AR activation on H+-ATPase localization.

Results

Co-localization study of β3-AR with either H+-ATPase or Cl−/HCO3− exchanger pendrin in mouse kidney showed that β3-AR is expressed in H+-secreting type A, in HCO3— secreting type B, and in non-A non-B ICs. The urine pH of β3-AR ko mice was significantly higher compared with wt mice. In line with these results, localization and expression analysis showed that renal H+-ATPase significantly decreased in β3-AR ko mice compared to wt mice, supporting the idea that H+ secretion is partially blunted in these animals. Of note, exposure of M1-β3-AR cells to a selective β3-AR agonist induced a 2.5 fold increase of H+-ATPase activity compared to resting cells and this effect was prevented by a selective β3-AR antagonist or by the H+-ATPase inhibitor bafilomycin. Moreover, β3-AR agonism enhanced H+-ATPase apical expression in M1-β3-AR cells. In addition, the PKA inhibitor H89 abolished the stimulatory effect of β3-AR agonism, demonstrating the involvement of the cAMP/PKA pathway.

Conclusion

The present data suggest that modulation of H+-ATPase activity in renal ICs by endogenous β3-AR agonists may play an addition physiological role in hormonal control of renal acid-base homeostasis.
SO040ROLE OF INTRACELLULAR CA2+ IN THE REGULATION OF THE RENAL CHLORIDE CHANNEL CLC-KA
Authors: Gerbino Andrea , De Zio Roberta , Russo Daniela , Milella Luigi , Milano Serena , Procino Giuseppe , Pusch Michael , Svelto Maria , Carmosino Monica
Published: June 2020

Background and Aims

It has been recognized that the physiological role of ClC-Ka and its mouse homolog ClC-K1 in the nephron is to confer high Cl- permeability in the thin Ascending Limb of loop of Henle (tAL), which in turn is essential for establishing the high osmolarity of the renal medulla in the countercurrent system. Accordingly ClC-K1 KO mice display a severe polyuria resembling a Nephrogenic Diabetes Insipidus (NDI) phenotype. Thus, ClC-Ka in human nephron could be an interesting target for diuretic and anti-hypertensive drugs. Unfortunately the regulation of ClC-Ka in and its electrophysiological properties are still not completely known.

Method

We analyzed, by whole-cell voltage-clamp, Cl- currents in HEK293 cells co-expressing GFP-ClC-Ka and the accessory m-Cherry-tagged barttin subunit, upon intracellular Ca2+ mobilization. The patch clamp protocol consists of a holding potential from 0 mV, which is stepped to various test potentials from -195 and +125 mV for 150 ms. Pulses ended with a tail pulse to -125 mV for 20 ms. Concomitantly we monitored by live confocal microscopy, the membrane expression of either GFP-ClC-Ka or barttin-mCherry.

Results

In control conditions we found a linear current/voltage relationship over a broad range of membrane voltages except of hyperpolarization below -100 mV, where the channel open probability was reduced, providing the well-known hook-shaped appearance of the I-V curve for ClC-Ka channel. Interestingly, both 100 µM ATP and 400 µg/ml of dandelion root extract (DRE), both increasing intracellular Ca2+ in HEK293, significantly inhibited Cl- currents in a time dependent way. Pre-treatment of cells with either the Ca2+ chelator BAPTA-AM or the PCK inhibitor Calphostin C, reverted the inhibitory effects of both ATP and DRE. Interestingly, 1µM of phorbol meristate acetate (PMA), a specific PKC activator, mimicked the inhibitory effect of ATP and DRE on Cl- currents. We finally demonstrated that 30 µM Heclin, an inhibitor of E3 ubiquitin ligase, did not revert the DRE- and ATP- induced Cl- currents inhibition, thus suggesting that the ClC-Ka inhibition is independent of channel ubiquitination. Accordingly, live confocal analysis showed that all the Ca2+ mobilizing compounds tested did not induced neither ClC-Ka nor Barttin internalization. We hypothesized that phosphorylation in the putative PKC consensus sites present in ClC-Ka amino acidic sequence may be involved in the inhibition of channel activity.

Conclusion

In conclusion, we demonstrated for the first time that the activity of ClC-Ka in renal cells could by inhibited by either receptor agonists or natural molecules able to activate an intracellular Ca2+/PKC pathway, thus opening venues for the development of new diuretic drugs.
SO041THE EFFECT AND MECAHNISM OF THE LOX IN AT1R/Β-ARRESTIN BIASED PATHWAY INDUCED RENAL INTERSTITIAL FIBROSIS
Authors: Zhang Xiaoqin , Yu Chen
Published: June 2020

Background and Aims

We studied the downstream and mechanism of β-arrestins signaling in renal fibrosis process and the role of lysyl oxidase (LOX) in the AT1R-β-arrestins pathway.

Method

The mechanism of β-arrestins signaling was studied in normal rat kidney tubule epithelial cells (NRK-52E) treated with SII in vitro. BAPN or placebo was administered during ischemia reperfusion (IR)-induced fibrosis progression. Collagen crosslinking and fibrosis progression were assessed histologically and biochemically.

Results

The mRNA and protein levels of β-arrestin-1 and β-arrestin-2 were significantly upregulated in renal fibrosis model both in vitro and in vivo. SII activated the ERK-STAT3 PY705 but not STAT3-Try727 in nucleus of NRK-52E cells, which effects were abolished when transfection of siRNA targeting β-arrestin-1 and β-arrestin-2 or pretreated with PD98059 (MEK inhibitor). LOX was strongly induced in fibrotic kidney and NRK-52E cells treated with SII. Active LOX significantly increased collagen crosslinking. In established IR-28d renal fibrosis, LOX inhibition promoted fibrosis reversal and with a 25% decrease insoluble collagen. Gene silencing of β-arrestin-1 + 2 or STAT3 apparently inhibited SII-induced LOX expression in vitro. Besides, chromatin immunoprecipitation (ChIP) assay clearly demonstrating the interaction between STAT3 and the LOX promoter, which indicated LOX is a direct target gene of SII-β-arrestins-STAT3 signaling.

Conclusion

The ERK/STAT3 was downstream of AT1R-β-arrestins, ERK entered the nucleus and activated STAT3-PY705. LOX mediates collagen crosslinking and fibrotic matrix stabilization during renal fibrosis via the AT1R-β-arrestins-ERK-STAT3-PY705 signaling. By blocking this profibrotic pathway, therapeutic LOX inhibition attenuates the fibrosis and suggesting target the LOX has significant potency for the treatment of patients with fibrotic kidney disorders.
SO043MALNUTRITION-INFLAMMATION IS A RISK FACTOR FOR BRAIN ATROPHY RELATIVE COGNITIVE IMPAIRMENT IN MAINTENANCE DIALYSIS PATIENTS
Authors: Qian Yujun , Zheng Ke , Lin Tianye , Feng Feng , Han Fei , Zhu Yicheng , Li Xuemei
Published: June 2020

Background and Aims

Cognitive impairment (CI) are prevalent and devastating in dialysis patients, whereas the pathophysiology is not very clear. Brain atrophy may involve in the process of CI. To explore the correlation between brain atrophy and cognitive impairment, as well as the risk factors of brain atrophy, we used the voxel based morphometry (VBM) method to evaluate the changes of brain multi-component volume in maintenance dialysis patients, and analyzed it relationship with detailed cognitive function.

Method

From July 2013 to July 2014, 181 maintenance dialysis patients in our hospital were enrolled for 3.0T MRI examination and cognitive function evaluation. The statistical parameter map (SPM) 8 software package was used for VBM analysis, and the Monte Carlo simulation method (alphasim method) in the functional neural image analysis software package (AFNI) was used for multiple comparison correction at the cluster level to extract the volume of brain multi-component. Cognitive function was evaluated with MMSE, MoCA, Philadelphia word learning test, Boston Naming Test, semantic fluency test and trial making test. The risk factors for brain volume were explored, and the correlation between brain volume and CI was investigated by regression analysis.

Results

This study enrolled 181 dialysis patients, including 119 cases of maintenance hemodialysis and 62 cases of peritoneal dialysis. According to MMSE and MoCA, the incidence of cognitive impairment was 22.7% and 66.3% respectively. The mean values gray matter volume and white matter volume were 575.4mm3 and 457.8mm3, respectively. The volume of gray matter, white matter, amygdala, caudate nucleus and hippocampus were positively correlated with the scores of specific cognitive functions such as total, memory, language and execution. Among them, amygdala volume atrophy was significantly related to the decrease of cognitive function such as MMSE (β = 2.81, P = 0.005), MoCA (β = 6.26, P < 0.001). Serum albumin is the risk factor of gray matter volume (β = 5.0, 95% CI = 3.1 to 6.9, P < 0.001) and white matter volume (β = 3.6, 95% CI = 1.7 to 5.5, P < 0.001); Serum Hypersensitive C-reactive protein is the risk factor of gray matter volume (β = -0.9, 95% CI = -1.7 to - 0.1, P = 0.037).

Conclusion

Brain atrophy in maintenance dialysis patients is closely related to multiple cognitive impairment, and malnutrition - microinflammation may be a risk factor for multi-component brain atrophy.
SO046REGULATION OF GUT MICROBIOTA AND HOST CO-METABOLISM BY POTASSIUM HOMEOSTASIS IN PATIENTS ON HEMODIALYSIS
Authors: Raj Dominic , Gao Bei , Barrows Elizabeth , Jagadeesan Muralidharan , Amdur Richard , Collins Ashte , Regunathan-Shenk Renu , Kincaid Danielle , Omar Badryah , Siddiqi Muhammad
Published: June 2020

Background and Aims

Gut microbiota composition is dysregulated in hemodialysis patients. However, the impact of potassium homeostasis on the gut microbiota and their metabolites has not been studied. Patiromer is a potassium binding polymer that exchanges calcium for potassium in the gastrointestinal (GI) tract, thereby increasing fecal potassium excretion and reducing serum potassium levels.

Method

In this non-randomized, open label, 3-period crossover trial with repeated measures within each period, we investigated the effect of 12 weeks of treatment with patiromer on the microbiome profile and microbiota-related metabolites in 27 hemodialysis patients using multi-omics integration of data from shotgun metagenomic sequencing and untargeted and targeted metabolomic profiling. Data from hemodialysis patients at baseline was first compared with individuals without kidney disease (n=20).

Results

We found that 18 bacterial species and 49 plasma chemical clusters were significantly different between patients and controls. Serum potassium decreased significantly from baseline (5.62±0.65 mEq/L) with patiromer treatment (4.80±0.46 meq/L) and increased during the post-treatment phase (5.45 ± 0.67 meq/L), (p<0.001). Three bacterial species and one bacterial pathway were altered by patiromer. We identified 52 serum metabolites, which were significantly different in patients at baseline compared with controls, and were partially reversed with patiromer treatment. Specifically, the serum levels of polyphenols such as vanillic acid, gallic acid and benzoic acid, and other microbiota-related metabolites such as 2,6-diaminopimelic acid, 2-ketogluconic acid, indole-3-carboxaldehyde and 3-hydroxyphenylacetic acid were reduced by patiromer treatment.

Conclusion

Our study suggests that control of hyperkalemia by patiromer alters the gut microbial composition and host co-metabolism in hemodialysis patients.
SO047HEMODIAFILTRATION DECREASES RISE OF LEPTIN AND RESISTIN IN PROTEIN ENERGY WASTING (PEW) WITHOUT HARMFULL EFFECT ON ALBUMIN CONCENTRATION
Authors: Hory Bernard , Robino Christophe
Published: June 2020

Background and Aims

The role of adipocytokines (ADCK), and particularly of anorectic leptin and of resistin in the mortality of PEW is strongly suspected. Convective techniques (ol-HDF) decrease leptin concentrations but induce a concomitant albumin loss which could be potentially harmful in malnourished patients. The aim of the prospective multicentric randomized study performed in France by the NUTRIPEPA GROUP is to compare one year evolution of 4 ADCK and seric albumin using HDF or HD and membranes with different cut-off.

Method

47 patients responding to both criteria of albumin <35 g/l (mean of 3 dosages) and prognostic inflammatory and nutritional index (PINI)≥ 1 were randomized to be treated using either polyester polyarylate (PEPA Nikkiso Japan) or polysufone, polyethersulfone dialyser (control) and followed for one year. Treatment consists in 3*4 hours HD session or in 3 HDF sessions with more than 20 liters reinjection/session. 24 patients were treated with HDF (HDF gr) : 11 with PEPA, 13 with control, and 23 with HD (HD gr) : 13 with PEPA, 10 with control. Oral nutritional supplementation was systematic, eventually completed by intradialytic parenteral nutrition. Albumin, leptin, adiponectin, ghrelin and resistin concentrations were determined at M0, M6, M9, M12. Delta concentration M0-M12 of albumin and of the 4 ADCK were compared with Wilcoxon test.

Results

At 12 months, decrease of leptin and of resistin was significantly higher in HDF group compare to HD group. There was no significant variation of adiponectin, ghrelin and albumin concentrations regardless of the technic or of dialyser cut-off.

Conclusion

In PEW, on a one year practice and regardless of the cut-off of the dialyser, HDF decreases both the anorexigenic adipokine leptin and resistin, adipokine implicated in insulin resistance, without harmfull incidence on seric albumin concentration. The decrease of concentrations of leptin and resistin obtained using ol-HDF could explain, at least in part, the reduction of one year mortality that we reported last year in preliminary results of NUTRIPEPA study.
SO056THE CLINICAL AND IMMUNOLOGICAL IMPACT OF LOW DOSE RITUXIMAB IN CLINICAL NEPHROLOGY
Authors: Alex Sunu
Published: June 2020

Background and Aims

Currently, the dose of rituximab used in nephrology practice is mostly extrapolated from the dose used in lymphoproliferative disorders. It is possible that a lesser dose may suffice when treating a non-neoplastic disorder. We conducted this study to study the clinical response and CD19 B cell suppression with a single dose of 100mg rituximab in nephrology practice

Method

This was a single center prospective study of role of 100mg rituximab as initial dose in steroid dependent (SDNS), frequently relapsing nephrotic syndrome (FRNS), idiopathic membranous nephropathy (MN) and high immunologic risk kidney transplantation with subsequent doses based on CD19 B cell reconstitution.

Results

Following 100mg rituximab in 42 patients, CD19 B cell percentage decreased from 16.3+7.6 to 0.3±0.3, 1.9±1.7 and 4.0±4.5 by 30, 90 and 180 days respectively. At 30th day, 40(95.2%) had CD19 B cell count <1%. Of the 30 patients with SDNS and FRNS followed up for one year, 29(96.7%) went into remission at day 30. Remission was sustained in 23(76.6%) at day 180 and 21(70%) at 1 year. There was significant decrease [P <0.001] in the dose of steroids needed to maintain remission at 180 days following rituximab (0.27±0.02mg/Kg to 0.02±0.00mg/Kg). Of the five patients with MN, four patients achieved remission by 6 months. Remission was sustained in three patients by 1 year. Of the 7 kidney transplant recipients, 2 had antibody mediated rejections though CD19 B cells were suppressed even at one year.

Conclusion

Low dose of 100 mg rituximab is sufficient to deplete CD19 B cells for up to 90days and is effective in inducing remission in SDNS and FRNS and MN. Targeting subsequent doses depending on CD19 B cell reconstitution may prevent relapses, limit toxicity and be cost effective.
SO060MONOCYTE-TO-LYMPHOCYTE RATIO, AN INDEPENDENT RISK FACTOR OF SURVIVAL IN HEMODIALYSIS PATIENTS: RESULTS FROM THE INTERNATIONAL MONDO CONSORTIUM
Authors: Bright Rupert , Ye Xiaoling , Woollard Kevin , Pusey Charles Dickson , Kotanko Peter , Duncan Neill
Published: June 2020

Background and Aims

Patients with end-stage kidney disease have a high prevalence of chronic inflammation and a higher risk of death. Previous work by our group has indicated a positive relationship between neutrophil counts and neutrophil-to-lymphocyte ratio (NLR) and mortality in a large and ethnically diverse dialysis population. Monocytes also have a crucial inflammatory role, but there has been limited study to date, an association between monocyte-to-lymphocyte ration (MLR) was reported in a small Chinese haemodialysis cohort. The aim of this analysis was to study the independent relationship between MLR and all-cause mortality in a large and ethnically diverse haemodialysis population.

Method

Four cohorts were described by phases of haemodialysis exposure: 1) acute phase cohort- first 90 days on HD as the baseline period with the subsequent 9 months as the follow-up period, 2) early-stable phase cohort- 91 days to the end of 1st year as the baseline followed with 1 year’s follow-up period, 3) mid-stable phase cohort- 2nd year as the baseline and the following 1 year as the follow-up, and 4) late-stable phase cohort- 3rd year as the baseline followed by a 7 year follow-up period. All-cause mortality was recorded during the 4 phases. Kaplan-Meier (KM) curves were applied to explore the association between MLR quartiles with mortality in the 4 cohorts. Cox proportional hazards models with spline terms (adjusted for age, gender, race, body mass index, diabetic (DM) and congestive heart failure (CHF)) were applied to explore the association between MLR levels and all-cause mortality in the cohorts.

Results

A total of 20,848 patients were included in acute phase cohort; 19,575 in the early-stable phase cohort, 16,515 patients in the mid-stable cohort, and 13,708 patients in the late-stable phase cohort. Notably, patients with higher baseline MLR by quartile tended to be older, male and with a higher percentage of DM and CHF as comorbidities. Lower lymphocyte count and higher neutrophil count, NLR, CRP were associated with higher MLR quartile (Table 1), consistent with the observed association with other markers of inflammation and malnutrition: lower albumin, phosphate and higher ferritin. Adjusted all-cause mortality was observed to be higher in patients with higher MLR quartile both in the KM and spline analyses (Figure 1 a & b) in all phase cohorts (data not shown).

Conclusion

There is a positive relationship between higher levels of MLR and adjusted all-cause mortality across all phase cohorts, including long-term follow-up in this large and ethnically diverse haemodialysis population. Higher levels of MLR are seen in patients with DM and CHF and are consistently observed with other markers of inflammation and malnutrition. This work supports the findings made previously in a more a restricted cohort and warrants further mechanistic investigation.
SO061SEX DIFFERENCES IN MORTALITY AMONG PEOPLE WITH END-STAGE KIDNEY DISEASE: DO WOMEN ALWAYS LIVE LONGER?
Authors: De La Mata Nicole , Macleod Grace , Kelly Patrick , Rosales Brenda , Masson Philip , Morton Rachael , Webster Angela
Published: June 2020

Background and Aims

Female life expectancies consistently exceed males in the general population. Yet, this survival advantage may not persist in the presence of a chronic disease due to sex-based differences or healthcare inequities. We aimed to explore sex differences in survival among people with end-stage kidney disease (ESKD) compared to the general population.

Method

We included the entire ESKD population in Australia, 1980-2013 and New Zealand, 1988-2012 from the Australian and New Zealand Dialysis and Transplant Registry. These were linked to national death registers to ascertain deaths and their causes. We estimated relative measures of survival, including standardized mortality ratios (SMR), cumulative relative survival and expected life years lost, using general population data (adjusting for country, age, sex and calendar year) to account for background mortality.

Results

Of the 60,823 ESKD patients, there were 25,042 females (41%) and 35,781 males (59%). Overall 34,417 deaths occurred over the 368,719 person-years of follow-up where a similar proportion of females (57%) and males (56%) died. While mortality sex differences within the ESKD population were minor, once compared to the general population female ESKD patients had greater excess deaths, worse relative survival and greater life years lost compared to male ESKD patients. Female ESKD patients had 12 times (SMR:11.5; 95%CI:11.3-11.7) and males had 7 times (SMR:6.7; 95%CI:6.7-6.8) the expected deaths, with the greatest sex disparity among younger ages and from cardiovascular disease. Relative survival was consistently lower in females (0.57, 95%CI:0.57-0.58 in males vs 0.54, 95%CI:0.54-0.55 in females at 5 years), where the excess mortality was 9% higher (95%CI:7-12%) in female ESKD patients (Fig 1A), adjusting for year and age. The average life years lost for female ESKD patients was 4-5 years greater than male ESKD patients (Average life years lost 25.9 years, 95%CI:25.1-26.7 in males and 31.4 years, 95%CI:30.5-32.1 in females aged 15 years at ESKD) (Fig 1B). Kidney transplantation reduced the sex differences in excess mortality, with similar relative survival (p=0.42; Fig 1C) and average life years lost reduced to 3-4 years for females (Fig 1D).

Conclusion

The impact of ESKD is more profound for women than men with greater excess mortality, however kidney transplantation attenuates these differences. Our findings show that chronic diseases and sex can compound to produce worse outcomes where women lose their survival advantage in the presence of ESKD.
SO066IS OXYGEN-PULSE A GOOD SURROGATE MARKER OF STROKE VOLUME DURING PEAK EXERCISE IN CHRONIC KIDNEY DISEASE?
Authors: Chinnappa Shanmugakumar , Mooney Andrew
Published: June 2020

Background and Aims

As there is growing interest in the benefits of exercise training in chronic kidney disease (CKD), it is important to understand the utility of conventional exercise test parameters in quantifying the cardiopulmonary fitness of patients with CKD. Merely extrapolating information from studies of healthy volunteers and heart failure (HF) patients would not suffice. In the present study we evaluated one such parameter, the peak O2-pulse [the rate of peak O2 consumption (VO2max) to peak heart rate (HR)] which is widely used as a surrogate for peak stroke volume (SV) in HF. We tested the hypothesis that peak O2-pulse is a good surrogate marker for peak stroke volume in CKD.

Method

A cross sectional study of 70 asymptomatic male non-diabetic CKD patients [CKD stages 2-5 (pre dialysis)] without primary cardiac disease. Data from 35 healthy volunteers & 25 HF patients was used for comparison. Specialised cardiopulmonary exercise (CPX) test with CO2 rebreathing technique was utilised to measure peak cardiac output (Qt) and peak SV non-invasively. VO2max was simultaneously measured. Peak O2-pulse was calculated as VO2max/Peak HR. Peripheral O2 extraction [C(a-v)O2] was derived using Fick’s equation, VO2 = Qt x C(a-v)O2. Pearson’s correlation, univariate and multivariate analyses were applied. Results are presented as mean±SD. P<0.05 is considered as significant.

Results

CKD patients had a mean age of 48.4±12.6 years and a mean eGFR of 33.8±25.5 ml/min. Whereas there was a very strong correlation between peak O2-pulse and peak SV in HF (R2= 0.81), the correlation was less robust in CKD (R2 = 0.49) (Fig 1). On multivariate analysis, in HF, peak SV was the major determinant of O2 pulse (β=1.03). The β for peak C(a-v)O2 was 0.44, both P < 10-3. However, in CKD both peak SV (β =0.76, P<10-3) and peak C(a-v)O2 (β=0.70, P<10-3) were significant determinants of O2-pulse rendering O2-pulse a poor surrogate of SV in CKD.

Conclusion

Based on the above results we reject the hypothesis that peak O2-pulse is a good surrogate marker of peak SV in CKD. The results highlight the pitfalls in the application of conventional CPX parameters in evaluating cardiopulmonary fitness in CKD. In view of the unique pathophysiology of the uraemic state further CKD-specific studies evaluating the central and peripheral determinants of aerobic exercise capacity are required.