Browsing by Subject "Kidney"
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Item Open Access Advancing drug discovery for glomerulopathies using stem-cell-derived kidney models.(Trends in pharmacological sciences, 2023-04) Barreto, Amanda D; Burt, Morgan A; Musah, SamiraChronic kidney disease (CKD) is an epidemic that affects millions worldwide. The glomerulus, a specialized unit of the nephron, is highly susceptible to injury. Human induced pluripotent stem cells (iPSCs) have emerged as an attractive resource for modeling kidney disease and therapeutic discovery.Item Open Access Aging Is Associated With Impaired Activation of Protein Homeostasis-Related Pathways After Cardiac Arrest in Mice.(Journal of the American Heart Association, 2018-09) Shen, Yuntian; Yan, Baihui; Zhao, Qiang; Wang, Zhuoran; Wu, Jiangbo; Ren, Jiafa; Wang, Wei; Yu, Shu; Sheng, Huaxin; Crowley, Steven D; Ding, Fei; Paschen, Wulf; Yang, WeiBackground The mechanisms underlying worse outcome at advanced age after cardiac arrest ( CA ) and resuscitation are not well understood. Because protein homeostasis (proteostasis) is essential for cellular and organismal health, but is impaired after CA , we investigated the effects of age on proteostasis-related prosurvival pathways activated after CA . Methods and Results Young (2-3 months old) and aged (21-22 months old) male C57Bl/6 mice were subjected to CA and cardiopulmonary resuscitation ( CPR ). Functional outcome and organ damage were evaluated by assessing neurologic deficits, histological features, and creatinine level. CA / CPR -related changes in small ubiquitin-like modifier conjugation, ubiquitination, and the unfolded protein response were analyzed by measuring mRNA and protein levels in the brain, kidney, and spinal cord. Thiamet-G was used to increase O-linked β-N-acetylglucosamine modification. After CA / CPR , aged mice had trended lower survival rates, more severe tissue damage in the brain and kidney, and poorer recovery of neurologic function compared with young mice. Furthermore, small ubiquitin-like modifier conjugation, ubiquitination, unfolded protein response, and O-linked β-N-acetylglucosamine modification were activated after CA / CPR in young mice, but their activation was impaired in aged mice. Finally, pharmacologically increasing O-linked β-N-acetylglucosamine modification after CA improved outcome. Conclusions Results suggest that impaired activation of prosurvival pathways contributes to worse outcome after CA / CPR in aged mice because restoration of proteostasis is critical to the survival of cells stressed by ischemia. Therefore, a pharmacologic intervention that targets aging-related impairment of proteostasis-related pathways after CA / CPR may represent a promising therapeutic strategy.Item Open Access An ultrathin membrane mediates tissue-specific morphogenesis and barrier function in a human kidney chip.(Science advances, 2024-06) Mou, Xingrui; Shah, Jessica; Roye, Yasmin; Du, Carolyn; Musah, SamiraOrgan-on-chip (OOC) systems are revolutionizing tissue engineering by providing dynamic models of tissue structure, organ-level function, and disease phenotypes using human cells. However, nonbiological components of OOC devices often limit the recapitulation of in vivo-like tissue-tissue cross-talk and morphogenesis. Here, we engineered a kidney glomerulus-on-a-chip that recapitulates glomerular morphogenesis and barrier function using a biomimetic ultrathin membrane and human-induced pluripotent stem cells. The resulting chip comprised a proximate epithelial-endothelial tissue interface, which reconstituted the selective molecular filtration function of healthy and diseased kidneys. In addition, fenestrated endothelium was successfully induced from human pluripotent stem cells in an OOC device, through in vivo-like paracrine signaling across the ultrathin membrane. Thus, this device provides a dynamic tissue engineering platform for modeling human kidney-specific morphogenesis and function, enabling mechanistic studies of stem cell differentiation, organ physiology, and pathophysiology.Item Open Access APOL1 channel blocker reduces proteinuria in FSGS.(Kidney international, 2023-08) Olabisi, Opeyemi AItem Open Access Association of Different Estimates of Renal Function With Cardiovascular Mortality and Bleeding in Atrial Fibrillation.(Journal of the American Heart Association, 2020-09) Hijazi, Ziad; Granger, Christopher B; Hohnloser, Stefan H; Westerbergh, Johan; Lindbäck, Johan; Alexander, John H; Keltai, Matyas; Parkhomenko, Alexander; López-Sendón, José L; Lopes, Renato D; Siegbahn, Agneta; Wallentin, LarsBackground We compared different methods of estimated glomerular filtration rate (eGFR) and their association with cardiovascular death and major bleeding in 14 980 patients with atrial fibrillation in the ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) trial. Methods and Results eGFR was calculated using equations based on creatinine (Cockcroft-Gault, Modification of Diet in Renal Disease, and Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI]) and/or cystatin C (CKD-EPICysC and CKD-EPICysC+Creatinine). These 5 eGFR equations, as well as the individual variables that are used in these equations, were assessed for correlation and discriminatory ability for cardiovascular death and major bleeding. The median age was 70.0 years, and 35.6% were women. The median eGFR was highest with Cockcroft-Gault (74.1 mL/min) and CKD-EPICysC (74.2 mL/min), and lowest with Modification of Diet in Renal Disease (66.5 mL/min). Correlation between methods ranged from 0.49 (Cockroft-Gault and CKD-EPICysC) to 0.99 (Modification of Diet in Renal Disease and CKD-EPI). Among the eGFR equations, those based on cystatin C yielded the highest C indices for cardiovascular death and major bleeding: 0.628 (CKD-EPICysC) and 0.612 (CKD-EPICysC+Creatinine), respectively. A model based on the variables within the different eGFR equations (age, sex, weight, creatinine, and cystatin C) yielded the highest discriminatory value for both outcomes, with a C index of 0.673 and 0.656, respectively. Conclusions In patients with atrial fibrillation on anticoagulation, correlation between eGFR calculated using different methods varied substantially. Cystatin C-based eGFRs seem to provide the most robust information for predicting death and bleeding. A model based on the individual variables within the eGFR equations, however, provided the highest discriminatory value. Our findings may help refine risk stratification in patients with atrial fibrillation and define how renal function should be determined in future atrial fibrillation studies. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT00412984.Item Open Access Autophagy enhances NFκB activity in specific tissue macrophages by sequestering A20 to boost antifungal immunity.(Nat Commun, 2015-01-22) Kanayama, M; Inoue, M; Danzaki, K; Hammer, G; He, Y; Shinohara, MLImmune responses must be well restrained in a steady state to avoid excessive inflammation. However, such restraints are quickly removed to exert antimicrobial responses. Here we report a role of autophagy in an early host antifungal response by enhancing NFκB activity through A20 sequestration. Enhancement of NFκB activation is achieved by autophagic depletion of A20, an NFκB inhibitor, in F4/80(hi) macrophages in the spleen, peritoneum and kidney. We show that p62, an autophagic adaptor protein, captures A20 to sequester it in the autophagosome. This allows the macrophages to release chemokines to recruit neutrophils. Indeed, mice lacking autophagy in myeloid cells show higher susceptibility to Candida albicans infection due to impairment in neutrophil recruitment. Thus, at least in the specific aforementioned tissues, autophagy appears to break A20-dependent suppression in F4/80(hi) macrophages, which express abundant A20 and contribute to the initiation of efficient innate immune responses.Item Open Access Cloning and expression of a human kidney cDNA for an alpha 2-adrenergic receptor subtype.(Proc Natl Acad Sci U S A, 1988-09) Regan, JW; Kobilka, TS; Yang-Feng, TL; Caron, MG; Lefkowitz, RJ; Kobilka, BKAn alpha 2-adrenergic receptor subtype has been cloned from a human kidney cDNA library using the gene for the human platelet alpha 2-adrenergic receptor as a probe. The deduced amino acid sequence resembles the human platelet alpha 2-adrenergic receptor and is consistent with the structure of other members of the family of guanine nucleotide-binding protein-coupled receptors. The cDNA was expressed in a mammalian cell line (COS-7), and the alpha 2-adrenergic ligand [3H]rauwolscine was bound. Competition curve analysis with a variety of adrenergic ligands suggests that this cDNA clone represents the alpha 2B-adrenergic receptor. The gene for this receptor is on human chromosome 4, whereas the gene for the human platelet alpha 2-adrenergic receptor (alpha 2A) lies on chromosome 10. This ability to express the receptor in mammalian cells, free of other adrenergic receptor subtypes, should help in developing more selective alpha-adrenergic ligands.Item Open Access Complement C4 inhibits systemic autoimmunity through a mechanism independent of complement receptors CR1 and CR2.(J Exp Med, 2000-11-06) Chen, Z; Koralov, SB; Kelsoe, GThe complement system enhances antibody responses to T-dependent antigens, but paradoxically, deficiencies in C1 and C4 are strongly linked to autoantibody production in humans. In mice, disruption of the C1qa gene also results in spontaneous autoimmunity. Moreover, deficiencies in C4 or complement receptors 1 and 2 (CR1/CR2) lead to reduced selection against autoreactive B cells and impaired humoral responses. These observations suggest that C1 and C4 act through CR1/CR2 to enhance humoral immunity and somehow suppress autoimmunity. Here we report high titers of spontaneous antinuclear antibody (ANA) in C4(-/)- mice. This systemic lupus erythematosus-like autoimmunity is highly penetrant; by 10 mo of age, all C4(-)(/)- females and most males produced ANA. In contrast, titers and frequencies of ANA in Cr2(-)(/)- mice, which are deficient in CR1 and CR2, never rose significantly above those in normal controls. Glomerular deposition of immune complexes (ICs), glomerulonephritis, and splenomegaly were observed in C4(-)(/)- but not Cr2(-)(/)- mice. C4(-)(/)-, but not Cr2(-)(/)-, mice accumulate activated T and B cells. Clearance of circulating ICs is impaired in preautoimmune C4(-)(/)-, but not Cr2(-)(/)-, mice. C4 deficiency causes spontaneous, lupus-like autoimmunity through a mechanism that is independent of CR1/CR2.Item Open Access COVID-19 tissue atlases reveal SARS-CoV-2 pathology and cellular targets.(Nature, 2021-07) Delorey, Toni M; Ziegler, Carly GK; Heimberg, Graham; Normand, Rachelly; Yang, Yiming; Segerstolpe, Åsa; Abbondanza, Domenic; Fleming, Stephen J; Subramanian, Ayshwarya; Montoro, Daniel T; Jagadeesh, Karthik A; Dey, Kushal K; Sen, Pritha; Slyper, Michal; Pita-Juárez, Yered H; Phillips, Devan; Biermann, Jana; Bloom-Ackermann, Zohar; Barkas, Nikolaos; Ganna, Andrea; Gomez, James; Melms, Johannes C; Katsyv, Igor; Normandin, Erica; Naderi, Pourya; Popov, Yury V; Raju, Siddharth S; Niezen, Sebastian; Tsai, Linus T-Y; Siddle, Katherine J; Sud, Malika; Tran, Victoria M; Vellarikkal, Shamsudheen K; Wang, Yiping; Amir-Zilberstein, Liat; Atri, Deepak S; Beechem, Joseph; Brook, Olga R; Chen, Jonathan; Divakar, Prajan; Dorceus, Phylicia; Engreitz, Jesse M; Essene, Adam; Fitzgerald, Donna M; Fropf, Robin; Gazal, Steven; Gould, Joshua; Grzyb, John; Harvey, Tyler; Hecht, Jonathan; Hether, Tyler; Jané-Valbuena, Judit; Leney-Greene, Michael; Ma, Hui; McCabe, Cristin; McLoughlin, Daniel E; Miller, Eric M; Muus, Christoph; Niemi, Mari; Padera, Robert; Pan, Liuliu; Pant, Deepti; Pe'er, Carmel; Pfiffner-Borges, Jenna; Pinto, Christopher J; Plaisted, Jacob; Reeves, Jason; Ross, Marty; Rudy, Melissa; Rueckert, Erroll H; Siciliano, Michelle; Sturm, Alexander; Todres, Ellen; Waghray, Avinash; Warren, Sarah; Zhang, Shuting; Zollinger, Daniel R; Cosimi, Lisa; Gupta, Rajat M; Hacohen, Nir; Hibshoosh, Hanina; Hide, Winston; Price, Alkes L; Rajagopal, Jayaraj; Tata, Purushothama Rao; Riedel, Stefan; Szabo, Gyongyi; Tickle, Timothy L; Ellinor, Patrick T; Hung, Deborah; Sabeti, Pardis C; Novak, Richard; Rogers, Robert; Ingber, Donald E; Jiang, Z Gordon; Juric, Dejan; Babadi, Mehrtash; Farhi, Samouil L; Izar, Benjamin; Stone, James R; Vlachos, Ioannis S; Solomon, Isaac H; Ashenberg, Orr; Porter, Caroline BM; Li, Bo; Shalek, Alex K; Villani, Alexandra-Chloé; Rozenblatt-Rosen, Orit; Regev, AvivCOVID-19, which is caused by SARS-CoV-2, can result in acute respiratory distress syndrome and multiple organ failure1-4, but little is known about its pathophysiology. Here we generated single-cell atlases of 24 lung, 16 kidney, 16 liver and 19 heart autopsy tissue samples and spatial atlases of 14 lung samples from donors who died of COVID-19. Integrated computational analysis uncovered substantial remodelling in the lung epithelial, immune and stromal compartments, with evidence of multiple paths of failed tissue regeneration, including defective alveolar type 2 differentiation and expansion of fibroblasts and putative TP63+ intrapulmonary basal-like progenitor cells. Viral RNAs were enriched in mononuclear phagocytic and endothelial lung cells, which induced specific host programs. Spatial analysis in lung distinguished inflammatory host responses in lung regions with and without viral RNA. Analysis of the other tissue atlases showed transcriptional alterations in multiple cell types in heart tissue from donors with COVID-19, and mapped cell types and genes implicated with disease severity based on COVID-19 genome-wide association studies. Our foundational dataset elucidates the biological effect of severe SARS-CoV-2 infection across the body, a key step towards new treatments.Item Open Access Creatinine- versus cystatin C-based renal function assessment in the Northern Manhattan Study.(PloS one, 2018-01) Husain, S Ali; Willey, Joshua Z; Park Moon, Yeseon; Elkind, Mitchell SV; Sacco, Ralph L; Wolf, Myles; Cheung, Ken; Wright, Clinton B; Mohan, SumitBACKGROUND:Accurate glomerular filtration rate estimation informs drug dosing and risk stratification. Body composition heterogeneity influences creatinine production and the precision of creatinine-based estimated glomerular filtration rate (eGFRcr) in the elderly. We compared chronic kidney disease (CKD) categorization using eGFRcr and cystatin C-based estimated GFR (eGFRcys) in an elderly, racially/ethnically diverse cohort to determine their concordance. METHODS:The Northern Manhattan Study (NOMAS) is a predominantly elderly, multi-ethnic cohort with a primary aim to study cardiovascular disease epidemiology. We included participants with concurrently measured creatinine and cystatin C. eGFRcr was calculated using the CKD-EPI 2009 equation. eGFRcys was calculated using the CKD-EPI 2012 equation. Logistic regression was used to estimate odds ratios and 95% confidence intervals of factors associated with reclassification from eGFRcr≥60ml/min/1.73m2 to eGFRcys<60ml/min/1.73m2. RESULTS:Participants (n = 2988, mean age 69±10yrs) were predominantly Hispanic, female, and overweight/obese. eGFRcys was lower than eGFRcr by mean 23mL/min/1.73m2. 51% of participants' CKD status was discordant, and only 28% maintained the same CKD stage by both measures. Most participants (78%) had eGFRcr≥60mL/min/1.73m2; among these, 64% had eGFRcys<60mL/min/1.73m2. Among participants with eGFRcr≥60mL/min/1.73m2, eGFRcys-based reclassification was more likely in those with age >65 years, obesity, current smoking, white race, and female sex. CONCLUSIONS:In a large, multiethnic, elderly cohort, we found a highly discrepant prevalence of CKD with eGFRcys versus eGFRcr. Determining the optimal method to estimate GFR in elderly populations needs urgent further study to improve risk stratification and drug dosing.Item Open Access Dynamics of PTH-induced disassembly of Npt2a/NHERF-1 complexes in living OK cells.(American journal of physiology. Renal physiology, 2011-01) Weinman, Edward J; Steplock, Deborah; Shenolikar, Shirish; Blanpied, Thomas AParathyroid hormone (PTH) inhibits the reabsorption of phosphate in the renal proximal tubule by disrupting the binding of the sodium-dependent phosphate transporter 2A (Npt2a) to the adapter protein sodium-hydrogen exchanger regulatory factor-1 (NHERF-1), a process initiated by activation of protein kinase C (PKC). To gain additional insights into the dynamic sequence of events, the time course of these responses was studied in living opossum kidney (OK) cells. Using a FRET-based biosensor, we found that PTH activated intracellular PKC within seconds to minutes. In cells expressing GFP-Npt2a and mCherry-NHERF, PTH did not affect the relative abundance of NHERF-1 but there was a significant and time-dependent decrease in the Npt2a/NHERF-1 ratio. The half-time to maximal dissociation was 15 to 20 min. By contrast, PTH had no effect on the fluorescence ratio for GFP-ezrin compared with mCherry-NHERF-1 at the apical surface. These experiments establish that PTH treatment of proximal tubule OK cells leads to rapid activation of PKC with the subsequent dissociation of Npt2a/NHERF-1 complexes. The association of NHERF-1 with Ezrin and their localization at the apical membrane, however, was unperturbed by PTH, thereby enabling the rapid recruitment and membrane reinsertion of Npt2a and other NHERF-1 targets on termination of the hormone response.Item Open Access Effects of Linagliptin on Cardiovascular and Kidney Outcomes in People With Normal and Reduced Kidney Function: Secondary Analysis of the CARMELINA Randomized Trial.(Diabetes care, 2020-08) Perkovic, Vlado; Toto, Robert; Cooper, Mark E; Mann, Johannes FE; Rosenstock, Julio; McGuire, Darren K; Kahn, Steven E; Marx, Nikolaus; Alexander, John H; Zinman, Bernard; Pfarr, Egon; Schnaidt, Sven; Meinicke, Thomas; von Eynatten, Maximillian; George, Jyothis T; Johansen, Odd Erik; Wanner, Christoph; CARMELINA investigatorsObjective
Type 2 diabetes is a leading cause of kidney failure, but few outcome trials proactively enrolled individuals with chronic kidney disease (CKD). We performed secondary analyses of cardiovascular (CV) and kidney outcomes across baseline estimated glomerular filtration rate (eGFR) categories (≥60, 45 to <60, 30 to <45, and <30 mL/min/1.73 m2) in Cardiovascular and Renal Microvascular Outcome Study With Linagliptin (CARMELINA), a cardiorenal placebo-controlled outcome trial of the dipeptidyl peptidase 4 inhibitor linagliptin (NCT01897532).Research design and methods
Participants with CV disease and/or CKD were included. The primary outcome was time to first occurrence of CV death, nonfatal myocardial infarction, or nonfatal stroke (three-point major adverse CV event [3P-MACE]), with a secondary outcome of renal death, end-stage kidney disease, or sustained ≥40% decrease in eGFR from baseline. Other end points included progression of albuminuria, change in HbA1c, and adverse events (AEs) including hypoglycemia.Results
A total of 6,979 subjects (mean age 65.9 years; eGFR 54.6 mL/min/1.73 m2; 80.1% albuminuria) were followed for 2.2 years. Across eGFR categories, linagliptin as compared with placebo did not affect the risk for 3P-MACE (hazard ratio 1.02 [95% CI 0.89, 1.17]) or the secondary kidney outcome (1.04 [0.89, 1.22]) (interaction P values >0.05). Regardless of eGFR, albuminuria progression was reduced with linagliptin, as was HbA1c, without increasing risk for hypoglycemia. AEs were balanced among groups overall and across eGFR categories.Conclusions
Across all GFR categories, in participants with type 2 diabetes and CKD and/or CV disease, there was no difference in risk for linagliptin versus placebo on CV and kidney events. Significant reductions in risk for albuminuria progression and HbA1c and no difference in AEs were observed.Item Open Access Evaluating renal lesions using deep-learning based extension of dual-energy FoV in dual-source CT-A retrospective pilot study.(European journal of radiology, 2021-06) Schwartz, Fides R; Clark, Darin P; Ding, Yuqin; Ramirez-Giraldo, Juan Carlos; Badea, Cristian T; Marin, DanielePurpose
Dual-source (DS) CT, dual-energy (DE) field of view (FoV) is limited to the size of the smaller detector array. The purpose was to establish a deep learning-based approach to DE extrapolation by estimating missing image data using data from both tubes to evaluate renal lesions.Method
A DE extrapolation deep-learning (DEEDL) algorithm had been trained on DECT data of 50 patients using a DSCT with DE-FoV = 33 cm (Somatom Flash). Data from 128 patients with known renal lesions falling within DE-FoV was retrospectively collected (100/140 kVp; reference dataset 1). A smaller DE-FoV = 20 cm was simulated excluding the renal lesion of interest (dataset 2) and the DEEDL was applied to this dataset. Output from the DEEDL algorithm was evaluated using ReconCT v14.1 and Syngo.via. Mean attenuation values in lesions on mixed images (HU) were compared calculating the root-mean-squared-error (RMSE) between the datasets using MATLAB R2019a.Results
The DEEDL algorithm performed well reproducing the image data of the kidney lesions (Bosniak 1 and 2: 125, Bosniak 2F: 6, Bosniak 3: 1 and Bosniak 4/(partially) solid: 32) with RSME values of 10.59 HU, 15.7 HU for attenuation, virtual non-contrast, respectively. The measurements performed in dataset 1 and 2 showed strong correlation with linear regression (r2: attenuation = 0.89, VNC = 0.63, iodine = 0.75), lesions were classified as enhancing with an accuracy of 0.91.Conclusion
This DEEDL algorithm can be used to reconstruct a full dual-energy FoV from restricted data, enabling reliable HU value measurements in areas not covered by the smaller FoV and evaluation of renal lesions.Item Open Access Experimental inhibition of porcupine-mediated Wnt O-acylation attenuates kidney fibrosis.(Kidney Int, 2016-05) Madan, Babita; Patel, Mehul B; Zhang, Jiandong; Bunte, Ralph M; Rudemiller, Nathan P; Griffiths, Robert; Virshup, David M; Crowley, Steven DActivated Wnt signaling is critical in the pathogenesis of renal fibrosis, a final common pathway for most forms of chronic kidney disease. Therapeutic intervention by inhibition of individual Wnts or downstream Wnt/β-catenin signaling has been proposed, but these approaches do not interrupt the functions of all Wnts nor block non-canonical Wnt signaling pathways. Alternatively, an orally bioavailable small molecule, Wnt-C59, blocks the catalytic activity of the Wnt-acyl transferase porcupine, and thereby prevents secretion of all Wnt isoforms. We found that inhibiting porcupine dramatically attenuates kidney fibrosis in the murine unilateral ureteral obstruction model. Wnt-C59 treatment similarly blunts collagen mRNA expression in the obstructed kidney. Consistent with its actions to broadly arrest Wnt signaling, porcupine inhibition reduces expression of Wnt target genes and bolsters nuclear exclusion of β-catenin in the kidney following ureteral obstruction. Importantly, prevention of Wnt secretion by Wnt-C59 blunts expression of inflammatory cytokines in the obstructed kidney that otherwise provoke a positive feedback loop of Wnt expression in collagen-producing fibroblasts and epithelial cells. Thus, therapeutic targeting of porcupine abrogates kidney fibrosis not only by overcoming the redundancy of individual Wnt isoforms but also by preventing upstream cytokine-induced Wnt generation. These findings reveal a novel therapeutic maneuver to protect the kidney from fibrosis by interrupting a pathogenic crosstalk loop between locally generated inflammatory cytokines and the Wnt/β-catenin signaling pathway.Item Open Access Exploring optimal settings for safe and effective thulium fibre laser lithotripsy in a kidney model.(BJU international, 2024-02) Mishra, Arpit; Medairos, Robert; Chen, Junqin; Soto-Palou, Francois; Wu, Yuan; Antonelli, Jodi; Preminger, Glenn M; Lipkin, Michael E; Zhong, PeiObjectives
To explore the optimal laser settings and treatment strategies for thulium fibre laser (TFL) lithotripsy, namely, those with the highest treatment efficiency, lowest thermal injury risk, and shortest procedure time.Materials and methods
An in vitro kidney model was used to assess the efficacy of TFL lithotripsy in the upper calyx. Stone ablation experiments were performed on BegoStone phantoms at different combinations of pulse energy (EP ) and frequency (F) to determine the optimal settings. Temperature changes and thermal injury risks were monitored using embedded thermocouples. Experiments were also performed on calcium oxalate monohydrate (COM) stones to validate the optimal settings.Results
High EP /low F settings demonstrated superior treatment efficiency compared to low EP /high F settings using the same power. Specifically, 0.8 J/12 Hz was the optimal setting, resulting in a twofold increase in treatment efficiency, a 39% reduction in energy expenditure per unit of ablated stone mass, a 35% reduction in residual fragments, and a 36% reduction in total procedure time compared to the 0.2 J/50 Hz setting for COM stones. Thermal injury risk assessment indicated that 10 W power settings with high EP /low F combinations remained below the threshold for tissue injury, while higher power settings (>10 W) consistently exceeded the safety threshold.Conclusions
Our findings suggest that high EP /low F settings, such as 0.8 J/12 Hz, are optimal for TFL lithotripsy in the treatment of COM stones. These settings demonstrated significantly improved treatment efficiency with reduced residual fragments compared to conventional settings while keeping the thermal dose below the injury threshold. This study highlights the importance of using the high EP /low F combination with low power settings, which maximizes treatment efficiency and minimizes potential thermal injury. Further studies are warranted to determine the optimal settings for TFL for treating kidney stones with different compositions.Item Open Access Fates of HIV-infected Renal Epithelial Cells Following Virus Acquisition from Infected Macrophages(2020) Hughes, Kelly TAlthough anti-retroviral therapy (ART) is effective at controlling HIV-1 replication, it does not eradicate the virus from viral reservoirs established throughout the body of infected individuals before therapy initiation.
Increasing evidence supports the kidney as such a reservoir. Although it is recognized that HIV-1 infects renal tubule epithelial (RTE) cells, how the virus enters kidney cells and their fate following infection requires further investigation. Previous work has demonstrated that HIV-1 infected CD4+ T-cells transfer virus to RTE through cell-to-cell contact. In addition to CD4+ T-cells, macrophages represent the other major target of HIV-1. Renal macrophages induce and regulate inflammatory responses and are critical to homeostatic regulation of the kidney environment. Combined with their ability to harbor virus, macrophages may also play an important role in the spread of HIV-1 infection in the kidney.
Here we show that macrophages are abundantly present in the renal inflammatory infiltrate of individuals with HIV-associated nephropathy (HIVAN). Using a co-culture system, we observed contact-dependent HIV-1 transfer from infected macrophages to both primary and immortalized renal cells. Live imaging of HIV-1 infected RTE cells revealed four different fates: proliferation, hypertrophy, latency and cell death.
The work described here indicates that macrophages may play an important role in the dissemination of HIV-1 in the kidney and that proliferation of infected renal cells may contribute to HIV-1 persistence in this compartment. Additionally, the model presented here shows that renal cell infection results in pathological changes consistent with what is seen in vivo.
Item Open Access Fenestrated Endothelial Cells across Organs: Insights into Kidney Function and Disease.(International journal of molecular sciences, 2024-08) Mou, Xingrui; Leeman, Sophia M; Roye, Yasmin; Miller, Carmen; Musah, SamiraIn the human body, the vascular system plays an indispensable role in maintaining homeostasis by supplying oxygen and nutrients to cells and organs and facilitating the removal of metabolic waste and toxins. Blood vessels-the key constituents of the vascular system-are composed of a layer of endothelial cells on their luminal surface. In most organs, tightly packed endothelial cells serve as a barrier separating blood and lymph from surrounding tissues. Intriguingly, endothelial cells in some tissues and organs (e.g., choroid plexus, liver sinusoids, small intestines, and kidney glomerulus) form transcellular pores called fenestrations that facilitate molecular and ionic transport across the vasculature and mediate immune responses through leukocyte transmigration. However, the development and unique functions of endothelial cell fenestrations across organs are yet to be fully uncovered. This review article provides an overview of fenestrated endothelial cells in multiple organs. We describe their development and organ-specific roles, with expanded discussions on their contributions to glomerular health and disease. We extend these discussions to highlight the dynamic changes in endothelial cell fenestrations in diabetic nephropathy, focal segmental glomerulosclerosis, Alport syndrome, and preeclampsia, and how these unique cellular features could be targeted for therapeutic development. Finally, we discuss emerging technologies for in vitro modeling of biological systems, and their relevance for advancing the current understanding of endothelial cell fenestrations in health and disease.Item Open Access Ferroptotic stress promotes the accumulation of pro-inflammatory proximal tubular cells in maladaptive renal repair.(eLife, 2021-07-19) Ide, Shintaro; Kobayashi, Yoshihiko; Ide, Kana; Strausser, Sarah A; Abe, Koki; Herbek, Savannah; O'Brien, Lori L; Crowley, Steven D; Barisoni, Laura; Tata, Aleksandra; Tata, Purushothama Rao; Souma, TomokazuOverwhelming lipid peroxidation induces ferroptotic stress and ferroptosis, a non-apoptotic form of regulated cell death that has been implicated in maladaptive renal repair in mice and humans. Using single-cell transcriptomic and mouse genetic approaches, we show that proximal tubular (PT) cells develop a molecularly distinct, pro-inflammatory state following injury. While these inflammatory PT cells transiently appear after mild injury and return to their original state without inducing fibrosis, after severe injury they accumulate and contribute to persistent inflammation. This transient inflammatory PT state significantly downregulates glutathione metabolism genes, making the cells vulnerable to ferroptotic stress. Genetic induction of high ferroptotic stress in these cells after mild injury leads to the accumulation of the inflammatory PT cells, enhancing inflammation and fibrosis. Our study broadens the roles of ferroptotic stress from being a trigger of regulated cell death to include the promotion and accumulation of proinflammatory cells that underlie maladaptive repair.Item Open Access G protein beta gamma subunits stimulate phosphorylation of Shc adapter protein.(Proc Natl Acad Sci U S A, 1995-09-26) Touhara, K; Hawes, BE; van Biesen, T; Lefkowitz, RJThe mechanism of mitogen-activated protein (MAP) kinase activation by pertussis toxin-sensitive Gi-coupled receptors is known to involve the beta gamma subunits of heterotrimeric G proteins (G beta gamma), p21ras activation, and an as-yet-unidentified tyrosine kinase. To investigate the mechanism of G beta gamma-stimulated p21ras activation, G beta gamma-mediated tyrosine phosphorylation was examined by overexpressing G beta gamma or alpha 2-C10 adrenergic receptors (ARs) that couple to Gi in COS-7 cells. Immunoprecipitation of phosphotyrosine-containing proteins revealed a 2- to 3-fold increase in the phosphorylation of two proteins of approximately 50 kDa (designated as p52) in G beta gamma-transfected cells or in alpha 2-C10 AR-transfected cells stimulated with the agonist UK-14304. The latter response was pertussis toxin sensitive. These proteins (p52) were also specifically immunoprecipitated with anti-Shc antibodies and comigrated with two Shc proteins, 46 and 52 kDa. The G beta gamma- or alpha 2-C10 AR-stimulated p52 (Shc) phosphorylation was inhibited by coexpression of the carboxyl terminus of beta-adrenergic receptor kinase (a G beta gamma-binding pleckstrin homology domain peptide) or by the tyrosine kinase inhibitors genistein and herbimycin A, but not by a dominant negative mutant of p21ras. Worthmannin, a specific inhibitor of phosphatidylinositol 3-kinase (PI3K) inhibited phosphorylation of p52 (Shc), implying involvement of PI3K. These results suggest that G beta gamma-stimulated Shc phosphorylation represents an early step in the pathway leading to p21ras activation, similar to the mechanism utilized by growth factor tyrosine kinase receptors.Item Open Access Implementation of automated reporting of estimated glomerular filtration rate among Veterans Affairs laboratories: a retrospective study.(BMC Med Inform Decis Mak, 2012-07-12) Hall, Rasheeda K; Wang, Virginia; Jackson, George L; Hammill, Bradley G; Maciejewski, Matthew L; Yano, Elizabeth M; Svetkey, Laura P; Patel, Uptal DBACKGROUND: Automated reporting of estimated glomerular filtration rate (eGFR) is a recent advance in laboratory information technology (IT) that generates a measure of kidney function with chemistry laboratory results to aid early detection of chronic kidney disease (CKD). Because accurate diagnosis of CKD is critical to optimal medical decision-making, several clinical practice guidelines have recommended the use of automated eGFR reporting. Since its introduction, automated eGFR reporting has not been uniformly implemented by U. S. laboratories despite the growing prevalence of CKD. CKD is highly prevalent within the Veterans Health Administration (VHA), and implementation of automated eGFR reporting within this integrated healthcare system has the potential to improve care. In July 2004, the VHA adopted automated eGFR reporting through a system-wide mandate for software implementation by individual VHA laboratories. This study examines the timing of software implementation by individual VHA laboratories and factors associated with implementation. METHODS: We performed a retrospective observational study of laboratories in VHA facilities from July 2004 to September 2009. Using laboratory data, we identified the status of implementation of automated eGFR reporting for each facility and the time to actual implementation from the date the VHA adopted its policy for automated eGFR reporting. Using survey and administrative data, we assessed facility organizational characteristics associated with implementation of automated eGFR reporting via bivariate analyses. RESULTS: Of 104 VHA laboratories, 88% implemented automated eGFR reporting in existing laboratory IT systems by the end of the study period. Time to initial implementation ranged from 0.2 to 4.0 years with a median of 1.8 years. All VHA facilities with on-site dialysis units implemented the eGFR software (52%, p<0.001). Other organizational characteristics were not statistically significant. CONCLUSIONS: The VHA did not have uniform implementation of automated eGFR reporting across its facilities. Facility-level organizational characteristics were not associated with implementation, and this suggests that decisions for implementation of this software are not related to facility-level quality improvement measures. Additional studies on implementation of laboratory IT, such as automated eGFR reporting, could identify factors that are related to more timely implementation and lead to better healthcare delivery.