Albumin Leakage Research Articles

Removal of α1-Microglobulin Using Post-Dilution Online Hemodiafiltration with Polymethylmethacrylate Membrane: An Open-Label, Single-Arm Study

Introduction: The removal of low- and medium-molecular-weight proteins has been improved with online hemodiafiltration (OL-HDF) and hemodialysis using high-flux membranes; however, the outcomes of patients with end-stage kidney disease (ESKD) undergoing dialysis treatment are still worse than in the general population. α₁-Microglobulin (α₁-m), with a molecular weight of 33,000 Da, may contribute to dialysis-related disorders and mortality. However, the removal is insufficient even with current OL-HDF using the polysulfone (PS) membrane, which is common in Japan. Polymethylmethacrylate (PMMA) membranes can remove medium- to high-molecular-weight proteins by adsorption. This study aimed to assess the efficacy of removing medium- to high-molecular-weight proteins, such as α₁-m and β₂-microglobulin (β₂-m), through post-dilution OL-HDF with PMMA (Post-PMMA). The assessment was conducted in comparison to pre-dilution OL-HDF with PS (Pre-PS), using an open-label, single-arm study. Methods: Seven patients with ESKD on Pre-PS underwent Post-PMMA with replacement volume of 30 mL/min (low flow) and 50 mL/min (high flow). Clearance and removal rates of α₁-m, β₂-m, small molecules, inflammatory cytokines, and albumin were measured at 60 and 240 min of treatment. Results: Clearance rates of α₁-m at 60 min were −2.8 ± 5.2 mL/min with Pre-PS, −0.4 ± 2.6 mL/min with Post-PMMA (low), and 0.6 ± 3.4 mL/min with Post-PMMA (high). The removal rate of α₁-m was higher in Post-PMMA than that in Pre-HDF-PS (Post-PMMA [high] 17.7 ± 5.9%, Post-PMMA [low] 15.0 ± 5.6%, and Pre-PS 4.1 ± 5.5%). Adsorption clearance of β₂-m was increased with Post-PMMA. Albumin leakage in Post-PMMA was not higher than that in Pre-PS. Conclusion: The removal rate of α₁-m with Post-PMMA was higher than that with Pre-PS. The PMMA membrane adsorbed β₂-m, suggesting the removal effect of medium- to high-molecular-weight proteins by the adsorption method. Since Post-PMMA effectively removes α₁-m without excessive albumin leakage, it will be useful for patients with ESKD, especially those with a poor nutritional status.

Downregulation of Nrp1 transcription promotes blood–brain barrier disruption following experimental cerebral ischemia–reperfusion

Disruption of the blood–brain barrier (BBB) following cerebral ischemia–reperfusion injury (CIRI) is a major factor in the pathophysiology of stroke. Endothelial cell–cell communication is essential for maintaining BBB integrity. By analyzing GSE227651 data, we found that a decrease in endothelial cell–cell communication mediated by Sema3/Nrp1 may be due to the downregulation of Nrp1 transcription, which could contribute to BBB breakdown after CIRI. We confirmed this hypothesis by using western blot analysis to show a reduction in Nrp1 protein levels in penumbra endothelial cells after CIRI in mice. We then overexpressed Nrp1 specifically in brain endothelial cells using adeno-associated virus in mice. Furthermore, Nrp1 overexpression had a protective effect on BBB integrity, as evidenced by a decrease in IgG and albumin leakage caused by CIRI in mice. Finally, we found that Nrp1 overexpression also reduced brain cell death and neurological deficits induced by cerebral ischemia–reperfusion in mice. Our findings suggest that Nrp1 downregulation may be a key factor in the breakdown of endothelial cell–cell communication and subsequent BBB disruption following CIRI. Targeting Nrp1-mediated pathways may be a promising approach for mitigating BBB damage and alleviating neurological consequences in stroke patients.

Relationship of cardiorenal risk factors with albuminuria based on age, smoking, glycaemic status and BMI: a retrospective cohort study of the UK Biobank data

IntroductionSmoking is harmful, and its cessation is recommended to prevent chronic kidney disease, which often begins with abnormal leakage of albumin in the urine, called albuminuria. Smoking cessation’s effect on...

Protective effects of GuanXinNing tablet (GXNT) on diabetic encephalopathy in zucker diabetic obesity (ZDF) rats

BackgroundDiabetic encephalopathy (DE) is a complication of diabetes that leads to cognitive and behavioral decline. Utilizing safe and effective complementary and alternative medications for its management is a wise choice. Previous studies have shown that GuanXinNing Tablet (GXNT), an oral preparation primarily derived from two Chinese herbs, Salvia miltiorrhiza Bge. and Ligusticum chuanxiong Hort., exerts a beneficial neuroprotective effect. In this study, we explored the protective effects of GXNT on DE in male Zucker diabetic fatty (ZDF) rats induced by a high-fat diet, aiming to ascertain its significance and potential mechanisms.MethodsZDF rats were induced to develop type 2 diabetes (T2DM) with DE by a high-fat diet and treated with GXNT for 8 weeks until they were 20 weeks old. Throughout the experiment, the animals’ vital parameters, such as body weight, were continuously monitored. Cognitive function was evaluated using the Y maze test. Biochemical kits were employed to analyze blood glucose, lipids, and vascular endothelial-related factors. Cerebrovascular lesions were assessed using magnetic resonance angiography (MRA) imaging. Brain lesions were evaluated using hematoxylin and eosin (H&E) staining and ultrastructure observation. IgG and albumin (ALB) leakage were detected using immunofluorescence.ResultsGXNT demonstrated an enhancement in the overall well-being of the animals. It notably improved cognitive and behavioral abilities, as demonstrated by extended retention time in the novel heterogeneous arm during the Y-maze test. GXNT effectively regulated glucose and lipid metabolism, reducing fasting and postprandial blood glucose, glycated hemoglobin (HbA1c), and total cholesterol (TC) levels. Additionally, it exhibited a protective effect on the vascular endothelium by reducing the serum TXB2/PGI2 ratio while elevating NO and PGI2 levels. Moreover, GXNT ameliorated stenosis and occlusion in cerebral vessel branches, increased the number of microvessels and neurons around the hippocampus, and improved microvascular occlusion in the cerebral cortex, along with addressing perivascular cell abnormalities. Immunofluorescence staining showed a decrease in the fluorescence intensity of IgG and ALB in the cerebral cortex.ConclusionsGXNT demonstrated a highly satisfactory protective effect on DE in ZDF rats. Its mechanism of action could be based on the regulation of glucolipid metabolism and its protective effect on the vascular endothelium.

Measurement of Blood-Brain Barrier Hyperpermeability Using Evans Blue Extravasation Assay.

Blood-brain barrier (BBB) dysfunction and hyperpermeability have been implicated in a myriad of brain pathologies. TheEvans Blue assay is one of the most popular methods for studying BBB integrity and permeability in rodent models of brain disorders. Under normal physiological conditions, the BBB is impermeable to albumin, so Evans Blue when injected intravenously binds to serum albumin and remains restricted within blood vessels. In traumatic and ischemic injuries, and other brain pathologies that result in BBB hyperpermeability, neighboring endothelial cells partially lose their close contacts to each other, and the BBB becomes permeable to proteins such as albumin. This paracellular leak of Evans blue-bound albumin is considered a reliable indicator of BBB dysfunction and hyperpermeability. Here, we describe the procedures for the evaluation of BBB integrity and hyperpermeability using Evans Blue extravasation assay in a mouse model of traumatic brain injury. The method described here focuses on intravenous injection of Evans Blue followed by Evans Blue dye extraction. This is followed by the measurement of fluorescence intensity of Evans Blue to determine the dye extravasation as a direct indicator of BBB hyperpermeability.

Renal Embolization-Induced Uremic Swine Model for Assessment of Next-Generation Implantable Hemodialyzers.

Reliable models of renal failure in large animals are critical to the successful translation of the next generation of renal replacement therapies (RRT) into humans. While models exist for the induction of renal failure, none are optimized for the implantation of devices to the retroperitoneal vasculature. We successfully piloted an embolization-to-implantation protocol enabling the first implant of a silicon nanopore membrane hemodialyzer (SNMHD) in a swine renal failure model. Renal arterial embolization is a non-invasive approach to near-total nephrectomy that preserves retroperitoneal anatomy for device implants. Silicon nanopore membranes (SNM) are efficient blood-compatible membranes that enable novel approaches to RRT. Yucatan minipigs underwent staged bilateral renal arterial embolization to induce renal failure, managed by intermittent hemodialysis. A small-scale arteriovenous SNMHD prototype was implanted into the retroperitoneum. Dialysate catheters were tunneled externally for connection to a dialysate recirculation pump. SNMHD clearance was determined by intermittent sampling of recirculating dialysate. Creatinine and urea clearance through the SNMHD were 76-105 mL/min/m2 and 140-165 mL/min/m2, respectively, without albumin leakage. Normalized creatinine and urea clearance measured in the SNMHD may translate to a fully implantable clinical-scale device. This pilot study establishes a path toward therapeutic testing of the clinical-scale SNMHD and other implantable RRT devices.

YangXueQingNaoWan attenuated blood brain barrier disruption after thrombolysis with tissue plasminogen activator in ischemia stroke

Ethnopharmacological relevantYangXueQingNaoWan (YXQNW), a compound Chinese medicine, has been widely used for dizziness, irritability, insomnia, and dreaminess caused by blood deficiency and liver hyperactivity in China. However, whether YXQNW can inhibit cerebral microvascular exudation and cerebral hemorrhage (CH) caused by blood brain barrier (BBB) damage after tissue plasminogen activator (tPA) still unknown. Aim of the researchTo observe the effect of YXQNW on cerebral microvascular exudation and CH after tPA and investigate its mechanism in protecting BBB. Materials and methodsMale C57BL/6 N mice suffered from ischemia stroke by mechanical detachment of carotid artery thrombi with the stimulation of ferric chloride. Then mice were treated with tPA (10 mg/kg) and/or YXQNW (0.72 g/kg) at 4.5 h. Cerebral blood flow (CBF), infarct size, survival rate, neurological scores, gait analysis, Evans blue extravasation, cerebral water content, fluorescein isothiocyanate-labeled albumin leakage, hemorrhage, junction and basement membrane proteins expression, leukocyte adhesion and matrix metalloproteinases (MMPs) expression were evaluated 24 h after tPA. Proteomics was used to identify target proteins. ResultsYXQNW inhibited cerebral infarction, neurobehavioral deficits, decreased survival, Evans blue leakage, albumin leakage, cerebral water content and CH after tPA thrombolysis; improved CBF, low-expression and degradation of junction proteins, basement membrane proteins, Arhgap21 and its downstream α-catenin and β-catenin proteins expression; and suppressed the increase of adherent leukocytes and the release of MMP-9 derived from macrophage. ConclusionYXQNW relieved BBB damage and attenuated cerebral microvascular exudation and CH after tPA thrombolysis. The effect of YXQNW on cerebral microvascular exudation was associated with the inhibition of the low-expression of junction proteins, especially AJs mediated by Rho GTPase-activating protein 21 (Arhgap21), while the effect on CH was associated with the inhibition of leukocyte adhesion, the release of MMP-9 derived from macrophage, and low-expression and degradation of collagen IV and laminin in the vascular basement membrane.

Comparison of survival for super high-flux hemodialysis (SHF-HD) with high albumin leakage versus online hemodiafiltration or SHF-HD with low albumin leakage: the SUPERB study

BackgroundSurvival is equivalent between super high-flux hemodialysis (SHF-HD) and online hemodiafiltration (OHDF) with similar albumin leakage. According to the 2013 Japanese dialyzer performance classification, survival on HD is optimal when a type II dialyzer (β2-microglobulin clearance ≥ 70 mL/min) is used. Here, we investigated whether survival could be improved by SHF-HD using a type II-b dialyzer (sieving coefficient for albumin ≥ 0.03) with high albumin leakage compared with OHDF or SHF-HD using a type II-a dialyzer (sieving coefficient for albumin < 0.03) with low albumin leakage.MethodsThis 3-year retrospective observational propensity score-matched study included 738 patients receiving SHF-HD (n = 310) or OHDF (n = 428) with a type II dialyzer at our institution between April 1 and July 1, 2017. Three-year all-cause mortality was compared for SHF-HD with high estimated albumin leakage (EAL) versus OHDF and SHF-HD with low EAL. Kaplan–Meier survival curves were compared using the log-rank test and hazard ratios were calculated by Cox regression analysis.ResultsMortality in SHF-HD with high EAL was significantly lower than OHDF with low EAL (each n = 52 after matching; P = 0.007, log-rank test). All the dialyzers used a polyethersulfone (PES) membrane, whereas none of the hemodiafilters had a PES membrane. In SHF-HD, mortality was significantly lower when EAL was ≥ 3.0 g/session than when EAL was < 3.0 g/session (each n = 115 after matching, P = 0.004, log-rank test) and when the dialyzer used was type II-b rather than type II-a (each n = 133 after matching, P = 0.001, log-rank test).ConclusionsThese findings suggest that survival is better on SHF-HD using a type II-b dialyzer with high albumin leakage than on OHDF with low albumin leakage or SHF-HD using a type II-a dialyzers. The PES used in the type II-b dialyzer may also have a beneficial effect on survival.

Conflicting findings on the effectiveness of hydrogen therapy for ameliorating vascular leakage in a 5-day post hypoxic-ischemic survival piglet model

Neonatal hypoxic-ischemic encephalopathy (HIE) is a major cause of morbidity and mortality in newborns in both high- and low-income countries. The important determinants of its pathophysiology are neural cells and vascular components. In neonatal HIE, increased vascular permeability due to damage to the blood–brain barrier is associated with seizures and poor outcomes in both translational and clinical studies. In our previous studies, hydrogen gas (H2) improved the neurological outcome of HIE and ameliorated the cell death. In this study, we used albumin immunohistochemistry to assess if H2 inhalation effectively reduced the cerebral vascular leakage. Of 33 piglets subjected to a hypoxic-ischemic insult, 26 piglets were ultimately analyzed. After the insult, the piglets were grouped into normothermia (NT), H2 ventilation (H2), therapeutic hypothermia (TH), and H2 combined with TH (H2-TH) groups. The ratio of albumin stained to unstained areas was analyzed and found to be lower in the H2 group than in the other groups, although the difference was not statistically significant. In this study, H2 therapy did not significantly improve albumin leakage despite the histological images suggesting signs of improvement. Further investigations are warranted to study the efficacy of H2 gas for vascular leakage in neonatal HIE.

#4519 CAN WE REPLACE URINE TESTING AND DELIVER A STEP CHANGE IN ACCESS TO RENOPROTECTIVE MEDICATIONS?

Abstract Background and Aims Albuminuria is a medical condition characterized by leakage of albumin into the urine due to kidney damage. The condition is diagnosed by heightened Albumin to Creatinine ratio in the urine (ACR) and is typically categorized into microalbuminuria (ACR ≥ 30, &amp;lt; 300 mg/g mg/g) and macroalbuminuria (ACR ≥ 300 mg/g). Currently, despite compelling data, only a minority of patients with diabetes, and rarely individuals without diabetes, are screened for albuminuria in a systematic way. ACR tests also present high intra-person variability, making it harder to identify meaningful biologic changes and increasing complexity of clinical trials. In this study we develop a method using machine learning to predict ACR level from Electronic Health Records, excluding urine tests, and validated the model for identifying patients with albuminuria. Identifying patients with undiagnosed albuminuria could help slow progression of kidney disease and be used to speed up recruitment to, and reduce screen failures in, clinical trials. Method We developed a Quantile Regression model for ACR using US Limited IBM MarketScan Explorys Claims-EMR Data Set (LCED). We included subjects who had an ACR test (0 &amp;lt; ACR ≤ 5000 mg/g) and was of at least 18 years of age. Patient demographics (age, sex), vital signs (BMI, Blood Pressure) and 8 common blood tests (Albumin, Bilirubin, Creatinine, HbA1C, Triglyceride, Glucose, White Blood Cell count &amp; ALT) were used as covariates. A tree based gradient boosting framework (LightGBM) was used to train the quantile regression models, viz., the 25-, 50-, and 75-percentiles of ACR conditioned on the covariates. The model was then validated on all qualified subjects in Optum's de-identified Clinformatics® Data Mart Database (2007-2021). We evaluated performance using the metrics Area Under the Curve (AUC), precision (PPV), specificity (TNR), and sensitivity (TPR). Finally, we use Kaplan-Meier estimates to compare the risk of progression to kidney failure as identified by ICD codes (Chronic kidney disease, stage 5; End stage renal disease; Dependence on renal dialysis; Unspecified kidney failure; Kidney transplant) of both the predicted and measured ACR values. Results A final cohort of 63,459 individuals matched the inclusion and exclusion criteria in LCED and 5,857,385 individuals in Optum. Using the 25% quantile to predict patients at risk, the model consistently reaches a PPV greater than 0.8 and a specificity (TNR) greater than 0.99 (Table 1). The risk of progression to kidney failure increases with both increased predicted and measured ACR (Figure 1). Conclusion The results show that the models have discriminative power in all datasets. It predicts both micro- and macro-albuminuria with a PPV above 80% for the 25-quartile. However, classification performance is lacking in sensitivity, i.e., subjects suffering from albuminuria may not be classified as such. By using the median prediction of ACR we identify patient subpopulations that have a risk of kidney failure at least on par with the true ACR subpopulation targeted. This means that the method can be used confidently to identify at-risk individuals. Therefore, our model is advantageous in applications such as identifying undiagnosed albuminuria and pre-screening for clinical trials, where high PPV is more important than sensitivity. We intend to validate the model further for outcomes prediction in an upcoming CKD trial.

Increased urinary albumin leakage is related to injuries of glomerular glycocalyx and podocytes, and associated with tubular dysfunction in preeclampsia.

The pathogenesis of preeclampsia (PE) is known to be endothelial cell damage; however, the existence of dysfunction in glomerular endothelial glycocalyx, podocytes and tubules remains unclear. The glomerular endothelial glycocalyx, basement membrane, podocytes, and tubules are permeability barriers against albumin excretion. This study aimed to assess the relationship between urinary albumin leakage and injuries of the glomerular endothelial glycocalyx, podocytes, and tubules in patients with PE. A total of 81 women with uncomplicated pregnancies (control, n=22), PE (PE, n=36), or gestational hypertension (GH) (GH, n=23) were enrolled. We assessed urinary albumin and serum hyaluronan for glycocalyx injuries, podocalyxin for podocytes injuries, and urinary N-acetyl-β-d-glucosaminidase (NAG) and liver-type fatty acid-binding protein (l-FABP) for renal tubular dysfunctions. The serum hyaluronan and the urinary podocalyxin levels were higher in the PE and GH groups. The urinary NAG and l-FABP levels were higher in the PE group. Urinary NAG and l-FABP levels positively correlated with urinary albumin excretion. Our findings suggest that increased urinary albumin leakage is related to injuries of the glycocalyx and podocytes, and associated with tubular dysfunction in pregnant women with PE. The clinical trial described in this paper was registered at the UMIN Clinical Trials Registry under registration number UMIN000047875. URL of registration: https://centre6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000054437.

The impact of aging on pulmonary microvascular endothelial cell barrier function

Elderly individuals have substantially elevated morbidity and mortality during conditions of lung injury. However, the precise underlying mechanisms leading to this elevated mortality are ill-defined. Lung injury is associated with damage to pulmonary microvascular endothelial cells (PMVEC) leading to a compromised vascular barrier, fluid and protein leakage into the tissue, and subsequent respiratory dysfunction. Cell-cell junctions, including adherens junctions and tight junctions, are crucial for the maintenance of the endothelial barrier and have been shown to be dysregulated in various disease models. Pilot data from our lab demonstrated increased pulmonary vascular leak in aged mice during lung injury compared to young mice. We hypothesized that aging contributes to PMVEC barrier dysfunction due to impaired cell-cell junction integrity.To address our hypothesis, PMVEC isolated from young and aged mice were cultured in vitro until a confluent monolayer was formed. Endothelial barrier integrity was assessed by Evans blue-labelled albumin flux across the monolayers, as well as immunofluorescence staining of the adherens junction protein, vascular endothelial (VE)-cadherin, and tight junction protein, claudin-5. Localization of leak in relation to junctional proteins was performed using the fluorescently labelled macromolecule, NeutrAvidin. Proteomics analysis was conducted to identify differentially enriched pathways in young and aged PMVEC.Endothelial monolayers from aged mice exhibited a significant increase in albumin leak associated with augmented VE-cadherin and claudin-5 disruption vs. endothelial monolayers form young mice. Furthermore, NeutrAvidin staining localized to paracellular regions with VE-cadherin discontinuity was increased in PMVEC monolayers from aged mice vs. young mice, suggesting that the junctional disruption in aged PMVEC was directly associated with leak. Proteomics analysis revealed pathways known to be implicated in endothelial barrier dysfunction, including regulation of oxidoreduction and protein processing and trafficking, that were altered in PMVEC from aged mice.In summary, PMVEC from aged mice exhibit compromised barrier function, which is directly associated with impaired cell-cell junction integrity. We will next validate and target protein pathways identified in our proteomics analysis that were dysregulated in aged PMVEC to potentially rescue age-induced barrier dysfunction. These findings may highlight molecular pathways involved in predisposing aged individuals to worsened outcomes during lung injury, which can help in the development of therapeutics. Funded by Lawson Health Research Institute, CIHR, and Western University This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

PD19-01 C3a/C3aR1 SIGNALING AS A CRUCIAL PATHOGENIC MECHANISM IN MEMBRANOUS NEPHROPATHY

You have accessJournal of UrologyCME1 Apr 2023PD19-01 C3a/C3aR1 SIGNALING AS A CRUCIAL PATHOGENIC MECHANISM IN MEMBRANOUS NEPHROPATHY Qi Zhang, Sofia Bin, Astgik Petrosyan, Valentina Villani, Kevin Lemley, Roger de Filippo, Laura Perin, Paolo Cravedi, and Stefano da Sacco Qi ZhangQi Zhang More articles by this author , Sofia BinSofia Bin More articles by this author , Astgik PetrosyanAstgik Petrosyan More articles by this author , Valentina VillaniValentina Villani More articles by this author , Kevin LemleyKevin Lemley More articles by this author , Roger de FilippoRoger de Filippo More articles by this author , Laura PerinLaura Perin More articles by this author , Paolo CravediPaolo Cravedi More articles by this author , and Stefano da SaccoStefano da Sacco More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003285.01AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Primary membranous nephropathy (MN) is a leading cause of nephrotic syndrome in adults worldwide caused by the deposition of anti-podocyte-antibodies in the glomerular subepithelial space. While complement deposition is thought to play a crucial pathogenic role, the exact effector mechanism of complement in MN is unclear due to the lack of in vitro and in vivo systems that can faithfully recapitulate human disease. We have developed a novel glomerulus-on-a-chip system (GOAC) using human primary podocytes and glomerular endothelial cells (GEC) and assessed functional response to human MN serum, role of membrane-attack-complex (MAC) formation and C3a/C3aR1 signaling in MN pathogenesis. METHODS: GOACs were exposed to anti-PLA2R+ sera from MN patients; sera from healthy individuals were used as control. Functional response was assessed by albumin permeability assay to evaluate permselectivity. Role of PLA2R1, IgGs, complement, MAC and C3a/C3aR1 signaling pathway were assessed by immunofluorescence, western blotting and functional analysis while mechanisms of action were explored by PCR arrays, proteomics and immunostaining. Results were confirmed in vitro using podocytes on which C3aR1 was silenced and in vivo using THSD7A induced MN in balb/c mice. RESULTS: Following exposure to sera from MN patients, we confirmed lgG deposition, complement activation and MAC formation accompanied by albumin leakage. PLA2R silencing on podocytes, IgG neutralization as well as complement inactivation successfully prevented injury while leakage still occurred following MAC inhibition. GOAC supplemented with C3aR1 antagonists as well as GOAC using podocytes in which C3aR1 was silenced were able to counteract glomerular filtration damage and prevent albumin leakage and lessen oxidative stress in podocytes. Efficacy of C3aR1 antagonists in preventing proteinuria was confirmed in vivo, substantiating our findings. CONCLUSIONS: We have successfully developed a glomerulus-on-a-chip system that closely mimics the GFB structure and provides a powerful tool for studying renal regenerative and disease mechanisms in proteinuric diseases. Using a combination of in vitro and in vivo models, we showed that C3a/C3aR signaling plays a dominant role in complement-mediated MN pathogenesis. Source of Funding: NIH NIDDK © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e577 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Qi Zhang More articles by this author Sofia Bin More articles by this author Astgik Petrosyan More articles by this author Valentina Villani More articles by this author Kevin Lemley More articles by this author Roger de Filippo More articles by this author Laura Perin More articles by this author Paolo Cravedi More articles by this author Stefano da Sacco More articles by this author Expand All Advertisement PDF downloadLoading ...

The Substitution of Fifty Percent of Combustible Tobacco Smoke Exposure With Either Electronic Cigarettes or Heated tobacco Products Did Not Attenuate Acute Lung Injury in an Animal Model.

To reduce the harmful health effects of combustible cigarette smoke (CS), some (CS) users attempt to substitute CS with electronic cigarettes (ECIG) and/or heated tobacco products (HTP). In this animal study, we evaluated the acute effects of substituting CS consumption with ECIG or HTP thus mimicking the dual users' approach, on the lungs of a mouse model. C57BL/6 mice were divided into Control, ECIG, HTP, CS, ECIG + CS, HTP + CS, and HTP + ECIG groups. Animals were exposed for 3 hours in AM and PM sessions to either air, CS, ECIG, or HTP for seven days. Lung injury was assessed by: wet to dry (W/D) ratio, albumin concentration in bronchoalveolar lavage fluid, expression of IL-1β, IL-6, and TNF-α, histopathology examination, reactive oxygen species (ROS) production, and assessment of cellular apoptosis. W/D ratio was significantly increased in mice exposed to CS only. Albumin leak and expression of IL-1β, IL-6, and TNF-a were elevated in CS, ECIG + CS, and HTP + CS. Histological examination revealed significant inflammatory cells infiltration, as well as collagen deposit in CS, ECIG + CS, HTP + CS. ROS production was significantly increased in CS, ECIG + CS, HTP + CS. Finally, cell death was also significantly increased in CS, ECIG + CS, and HTP + CS. In this animal model, substituting 50% of daily CS exposure by either ECIG or HTP exposure did not result in significant attenuation of acute lung injury.

Not all vaping is the same: differential pulmonary effects of vaping cannabidiol versus nicotine

RationaleVaping has become a popular method of inhaling various psychoactive substances. While evaluating respiratory effects of vaping have primarily focused on nicotine-containing products, cannabidiol (CBD)-vaping is increasingly becoming popular. It...

T-cell infiltration in the central nervous system and their association with brain calcification in Slc20a2-deficient mice.

Primary familial brain calcification (PFBC) is a rare neurodegenerative and neuropsychiatric disorder characterized by bilateral symmetric intracranial calcification along the microvessels or inside neuronal cells in the basal ganglia, thalamus, and cerebellum. Slc20a2 homozygous (HO) knockout mice are the most commonly used model to simulate the brain calcification phenotype observed in human patients. However, the cellular and molecular mechanisms related to brain calcification, particularly at the early stage much prior to the emergence of brain calcification, remain largely unknown. In this study, we quantified the central nervous system (CNS)-infiltrating T-cells of different age groups of Slc20a2-HO and matched wild type mice and found CD45+CD3+ T-cells to be significantly increased in the brain parenchyma, even in the pre-calcification stage of 1-month-old -HO mice. The accumulation of the CD3+ T-cells appeared to be associated with the severity of brain calcification. Further immunophenotyping revealed that the two main subtypes that had increased in the brain were CD3+ CD4- CD8- and CD3+ CD4+ T-cells. The expression of endothelial cell (EC) adhesion molecules increased, while that of tight and adherents junction proteins decreased, providing the molecular precondition for T-cell recruitment to ECs and paracellular migration into the brain. The fusion of lymphocytes and EC membranes and transcellular migration of CD3-related gold particles were captured, suggesting enhancement of transcytosis in the brain ECs. Exogenous fluorescent tracers and endogenous IgG and albumin leakage also revealed an impairment of transcellular pathway in the ECs. FTY720 significantly alleviated brain calcification, probably by reducing T-cell infiltration, modulating neuroinflammation and ossification process, and enhancing the autophagy and phagocytosis of CNS-resident immune cells. This study clearly demonstrated CNS-infiltrating T-cells to be associated with the progression of brain calcification. Impairment of blood-brain barrier (BBB) permeability, which was closely related to T-cell invasion into the CNS, could be explained by the BBB alterations of an increase in the paracellular and transcellular pathways of brain ECs. FTY720 was found to be a potential drug to protect patients from PFBC-related lesions in the future.

Warburg Effect as a Novel Mechanism for Homocysteine-Induced Features of Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) is a major cause of blindness. Recent studies have reported impaired glycolysis in AMD patients with a high lactate/pyruvate ratio. Elevated homocysteine (Hcy) (Hyperhomocysteinemia, HHcy) was observed in several clinical studies, reporting an association between HHcy and AMD. We established the effect of HHcy on barrier function, retinal pigment epithelium (RPE) structure, and induced choroidal neovascularization (CNV) in mice. We hypothesize that HHcy contributes to AMD by inducing a metabolic switch in the mitochondria, in which cells predominantly produce energy by the high rate of glycolysis, or "Warburg", effect. Increased glycolysis results in an increased production of lactate, cellular acidity, activation of angiogenesis, RPE barrier dysfunction, and CNV. Evaluation of cellular energy production under HHcy was assessed by seahorse analysis, immunofluorescence, and western blot experiments. The seahorse analysis evaluated the extracellular acidification rate (ECAR) as indicative of glycolysis. HHcy showed a significant increase in ECAR both in vivo using (Cystathionine β-synthase) cbs+/- and cbs-/- mice retinas and in vitro (Hcy-treated ARPE-19) compared to wild-type mice and RPE cells. Moreover, HHcy up-regulated glycolytic enzyme (Glucose transporter-1 (GlUT-1), lactate dehydrogenase (LDH), and hexokinase 1 (HK1)) in Hcy-treated ARPE-19 and primary RPE cells isolated from cbs+/+, cbs+/-, and cbs-/- mice retinas. Inhibition of GLUT-1 or blocking of N-methyl-D-aspartate receptors (NMDAR) reduced glycolysis in Hcy-treated RPE and improved albumin leakage and CNV induction in Hcy-injected mice eyes. The current study suggests that HHcy causes a metabolic switch in the RPE cells from mitochondrial respiration to glycolysis during AMD and confirms the involvement of NMDAR in this process. Therefore, targeting Glycolysis or NMDAR could be a novel therapeutic target for AMD.

PS-B09-3: EXAMINATION OF ALBUMINURIA REDUCTION EFFECT THROUGH IMPROVEMENT OF ENOS UNCOUPLING BY SGLT2 IN TYPE 2 DIABETIC MICE

Background and Aims: One of the main mechanisms of the renoprotective effects of SCLT2is in DKD is considered the ability of these inhibitors to improve glomerular hyperfiltration. We previously demonstrated that the adenosine/adenosine A1 receptor pathway played a pivotal role in the tubuloglomerular feedback(TGF) system in a type 1 diabetic model, Akita mice (Circulation, 2019). We also reported that the uncoupling of endothelial nitric oxide (NO) synthase (eNOS) via oxidation of tetrahydrobiopterin (BH4), a cofactor required for NO production, played a major role in generation of oxidative stress (AJPRP, 2005; JASN, 2013). In the present study, we explored the renal protective effects of SGLT2 inhibition, with a focus on glomerular oxidative stress and glomerular hemodynamics. Methods: This study used type 2 diabetic db/db mice and db/m+ mice as a control (male, 8wk old). In the first experiment, we measured the glomerular filtration rate of single nephrons (SNGFRs) using in vivo imaging technique in 12 wk-old db/db and db/m+ mice to confirm glomerular hyperfiltration. Next, we evaluated the SNGFRs change before and after the administration of a single dose of canagliflozin (CANA) (10 mg/kg). The SNGFRs, glomerular permeability of macromolecules, glomerular reactive oxygen species (ROS) and NO production, and tetrahydrobiopterin (BH4) level in serum and kidney were evaluated after the CANA treatment for 8 wk. Finally, human glomerular endothelial cells (hGECs) were exposed to normal glucose (5 mmol/L), high glucose (30 mmol/L of D-glucose), or a hyperosmotic control (5 mmol/L of D-glucose plus 25 mmol/L of L-glucose) in the presence or absence of CANA (10umol/L). Results: The CANA treatment ameliorated glomerular hyperfiltration in the db/db mice. In the db/db mice, glomerulus ROS production increased, and NO production decreased as compared with the levels in the control mice. CANA improved the imbalance between ROS and NO production. The serum and kidney concentrations of BH4 declined in the non-treated db/db mice, whereas the CANA treatment preserved the BH4 level. Leakage of 70-kD FITC-labeled albumin into the urinary space was observed in the db/db mice. The CANA treatment reduced the amount of FITC-labeled albumin in the urinary space of the db/db mice. The CANA treatment also alleviated vascular endothelial damage in glomeruli. BH4 levels decreased in the hGECs exposed to high glucose. CANA did not improved BH4 level in the hGECs exposed to high glucose. Conclusions: SGLT2i improved glomerular ROS/NO imbalance by suppressing eNOS uncoupling of glomerular endothelial cells in type 2 diabetic mice.

Effects of high albumin leakage on survival between online hemodiafiltration and super high-flux hemodialysis: the HISTORY study

BackgroundAll-cause mortality is lower with a high substitution volume in predilution (pre) and postdilution (post) online hemodiafiltration (OHDF) than with hemodialysis (HD), and mortality does not significantly differ between pre- and post-OHDF groups. Despite the improved survival with a high substitution volume, there may be limitations. On the other hand, either normoalbuminemia or high albumin leakage in HD can reduce mortality, and super high-flux (SHF) membrane dialyzers can reduce mortality compared with low-flux and high-flux membrane dialyzers. Here, we investigated the associations of serum albumin concentration (s-Alb), albumin leakage, and substitution volume with all-cause mortality in OHDF and SHF-HD.MethodsIn a 3-year retrospective observational study of patients receiving dialysis from April 1 to July 1, 2017, we developed a propensity score-matched model using 783 stable patients (SHF-HD, 355; OHDF, 428). We used the log-rank test to compare Kaplan–Meier survival curves and Cox regression analysis to calculate hazard ratio (HR). Cox regression analysis was also used to compare the effect of estimated albumin leakage (EAL) and substitution volume on 3-year all-cause mortality.ResultsAll-cause mortality was significantly lower with high EAL than with low EAL (SHF-HD: P = 0.012, log-rank test; HR, 0.44; 95% confidence interval [CI] 0.23–0.85; OHDF: P = 0.027, log-rank test; HR, 0.41; 95% CI 0.18–0.93). The mortality of high EAL was not significantly different between high and low s-Alb in SHF-HD (3.5 ± 0.1 and 3.2 ± 0.2 g/dL) and OHDF (3.6 ± 0.2 and 3.2 ± 0.1 g/dL), despite significant differences in s-Alb. Mortality did not significantly differ between SHF-HD and OHDF with higher EAL ranges or a lower difference in EAL. Mortality in pre-OHDF was significantly correlated with EAL (P = 0.007, beta − 0.32) rather than substitution volume, and mortality in post-OHDF was not analyzed because of fewer deaths.ConclusionsThe results suggest that survival is improved more with high EAL than with low EAL in both OHDF and SHF-HD patients, that high EAL with mild-to-moderate hypoalbuminemia does not necessarily worsen survival in OHDF and SHF-HD patients, and that survival is equivalent between OHDF and SHF-HD patients with a similar level of EAL.

Why Do the Mechanistic Actions of Albumin Not Translate Into Tangible Clinical Benefits?

Albumin has only reduced crude mortality in one randomized controlled trial conducted to date. This raises the question as to why potentially beneficial oncotic and pleiotropic properties of albumin do not consistently translate into clinically important outcomes. Four postulated explanations are provided as to why the theoretical advantages of albumin are not apparent in clinical trials: diminished oncotic action due to leakage of albumin from the intravascular compartment, modification of the pleiotropic properties of albumin both in vitro and in vivo, the ability of other plasma proteins to take over the major functions of albumin, and possible adverse effects.