Objective: To assess the predictive accuracy of the sFlt-1/PlGF ratio cut-off 38 in addition to the standard-of-care spot urine protein/creatinine ratio (PCr) for multiple pregnancies in women with... Show moreObjective: To assess the predictive accuracy of the sFlt-1/PlGF ratio cut-off 38 in addition to the standard-of-care spot urine protein/creatinine ratio (PCr) for multiple pregnancies in women with suspected pre-eclampsia. Study design: Post-hoc analysis of a prospective cohort study. Main outcome measures: Primary outcome was the occurrence of pre-eclampsia in one and four weeks after presentation with suspected pre-eclampsia. Test characteristics with 95% confidence intervals (CI) were calculated on pre-eclampsia development in one and four weeks. Results: Twenty-three multiple pregnancies with suspected pre-eclampsia between 20 and 37 weeks gestation were included for analysis. Women who eventually developed pre-eclampsia had a significantly higher PCr (34.0 vs. 16.5, p = 0.015), sFlt-1 (17033 vs. 5270 pg/ml, p = 0.047) and sFlt-1/PlGF ratio (99 vs. 25, p = 0.033) at baseline. Furthermore, PCr ≥ 30 and sFlt-1/PlGF ratio > 38 was respectively seen in 1/16 (6.3 %) and 3/16 (18.8 %) of the women who did not develop pre-eclampsia. For predicting pre-eclampsia within one week the sFlt-1/PlGF ratio sensitivity was 75.0 % [95 % CI 19.4–99.4] and the negative predictive value 93.8 % [73.0–98.8], while no pre-eclampsia developed when PCr was < 30. Consequently, the combination of these tests did not lead to an improvement in test characteristics, with non-significant differences in positive predictive value (50.0 % [29.5–70.5] versus 80.0 % [37.3–96.4]) compared to PCr alone for pre-eclampsia development in one week. Conclusions: In addition to standard-of-care spot urine PCr measurements, this study has not been able to demonstrate that the sFlt-1/PlGF ratio cut-off 38 is of added value in the prediction of pre-eclampsia in multiple pregnancy. Show less
The growing disparity between the demand for transplants and the available donor supply, coupled with an aging donor population and increasing prevalence of chronic diseases, highlights the urgent... Show moreThe growing disparity between the demand for transplants and the available donor supply, coupled with an aging donor population and increasing prevalence of chronic diseases, highlights the urgent need for the development of platforms enabling reconditioning, repair, and regeneration of deceased donor organs. This necessitates the ability to preserve metabolically active kidneys ex vivo for days. However, current kidney normothermic machine perfusion (NMP) approaches allow metabolic preservation only for hours. Here we show that human kidneys discarded for transplantation can be preserved in a metabolically active state up to 4 days when perfused with a cell-free perfusate supplemented with TCA cycle intermediates at subnormothermia (25 °C). Using spatially resolved isotope tracing we demonstrate preserved metabolic fluxes in the kidney microenvironment up to Day 4 of perfusion. Beyond Day 4, significant changes were observed in renal cell populations through spatial lipidomics, and increases in injury markers such as LDH, NGAL and oxidized lipids. Finally, we demonstrate that perfused kidneys maintain functional parameters up to Day 4. Collectively, these findings provide evidence that this approach enables metabolic and functional preservation of human kidneys over multiple days, establishing a solid foundation for future clinical investigations. Show less
Yuan, L.S.; Verhoeven, A.; Blomberg, N.; Eyk, H.J. van; Bizino, M.B.; Rensen, P.C.N.; ... ; Berg, B.M. van den 2024
Type 2 diabetes mellitus (T2DM) poses a higher risk for complications in South Asian individuals compared to other ethnic groups. To shed light on potential mediating factors, we investigated... Show moreType 2 diabetes mellitus (T2DM) poses a higher risk for complications in South Asian individuals compared to other ethnic groups. To shed light on potential mediating factors, we investigated lipidomic changes in plasma of Dutch South Asians (DSA) and Dutch white Caucasians (DwC) with and without T2DM and explore their associations with clinical features. Using a targeted quantitative lipidomics platform, monitoring over 1000 lipids across 17 classes, along with 1H NMR based lipoprotein analysis, we studied 51 healthy participants (21 DSA, 30 DwC) and 92 T2DM patients (47 DSA, 45 DwC) from the MAGNetic resonance Assessment of VICTOza efficacy in the Regression of cardiovascular dysfunction in type 2 dIAbetes mellitus (MAGNA VICTORIA) study. This comprehensive mapping of the circulating lipidome allowed us to identify relevant lipid modules through unbiased weighted correlation network analysis, as well as disease and ethnicity related key mediatory lipids. Significant differences in lipidomic profiles, encompassing various lipid classes and species, were observed between T2DM patients and healthy controls in both the DSA and DwC populations. Our analyses revealed that healthy DSA, but not DwC, controls already exhibited a lipid profile prone to develop T2DM. Particularly, in DSA-T2DM patients, specific lipid changes correlated with clinical features, particularly diacylglycerols (DGs), showing significant associations with glycemic control and renal function. Our findings highlight an ethnic distinction in lipid modules influencing clinical outcomes in renal health. We discover distinctive ethnic disparities of the circulating lipidome and identify ethnicity-specific lipid markers. Jointly, our discoveries show great potential as personalized biomarkers for the assessment of glycemic control and renal function in DSA-T2DM individuals. Show less
Arends, E.J.; Meziyerh, S.; Moes, D.J.A.R.; Kamerling, S.W.A.; Kooy, S. van der; Ogando, N.S.; ... ; Teng, Y.K.O. 2023
Introduction: Immunocompromised kidney patients are at increased risk of prolonged SARS-CoV-2 infection and related complications. Preclinical evidence demonstrates a more potent inhibitory effect... Show moreIntroduction: Immunocompromised kidney patients are at increased risk of prolonged SARS-CoV-2 infection and related complications. Preclinical evidence demonstrates a more potent inhibitory effect of voclosporin on SARS-CoV-2 replication than tacrolimus in vitro. We investigated the potential antiviral effects of voclosporin on SARS-CoV-2 in immunocompromised patients.Methods: First, we conducted a prospective, randomized, open-label, proof-of-concept study in 20 kidney transplant recipients (KTRs) on tacrolimus-based immunosuppression who contracted mild to moderate SARS-CoV-2 infection. Patients were randomized to continue tacrolimus or switch to voclosporin. Second, we performed a post hoc analysis on SARS-CoV-2 infections in 216 patients with lupus nephritis (LN) on standard immunosuppression who were randomly exposed to voclosporin or placebo as part of a clinical trial that was conducted during the worldwide COVID-19 pandemic. Results: The primary end point was clearance of SARS-CoV-2 viral load and that did not differ between voclosporin-treated KTRs (median 12 days, interquartile range [IQR] 8-28) and tacrolimus-treated KTRs (median 12 days, IQR 4-16) nor was there a difference in clinical recovery. Pharmacokinetic analyses demonstrated that, when voclosporin trough levels were on-target, SARS-CoV-2 viral load dropped significantly more (DCt 7.7 [3.4-10.7]) compared to tacrolimus-treated KTRs (DCt 2.7 [2.0-4.3]; P 1/4 0.035). In voclosporin-exposed patients with LN, SARS-CoV-2 infection was detected in 6% (7/116) compared to 12% (12/100) in placebo-exposed patients (relative risk [RR] 1.4 [0.97-2.06]). Notably, no voclosporin-exposed patients with LN died from severe SARS-CoV-2 infection compared to 3% (3/100) in placebo-exposed patients (RR 2.2 [1.90-2.54]).Conclusion: This proof-of-concept study shows a potential positive risk-benefit profile for voclosporin in immunocompromised patients with SARS-CoV-2 infection. These results warrant further investigations on voclosporin to establish an equipoise between infection and maintenance immunosuppression. Show less
Fibrotic diseases are characterized by the uncontrolled accumulation of extracellular matrix (ECM) components leading to disruption of tissue homeostasis. Myofibroblasts as the main ECM-producing... Show moreFibrotic diseases are characterized by the uncontrolled accumulation of extracellular matrix (ECM) components leading to disruption of tissue homeostasis. Myofibroblasts as the main ECM-producing cells can originate from various differentiated cell types after injury. Particularly, the process of endothelial-to-mesenchymal transition (endMT), describing phenotypic shifts of endothelial cells to adopt a fully mesenchymal identity, may contribute to the pool of myofibroblasts in fibrosis, while leading to capillary rarefaction and exacerbation of tissue hypoxia. In renal disease, incomplete recovery from acute kidney injury (AKI) and the ensuing fibrotic reaction stand out as major contributors to chronic kidney disease (CKD) development. While the focus has largely been on impaired tubular epithelial repair as a potential fibrosis-driving mechanism, alterations in the renal microcirculation post-AKI, and in particular endMT as a maladaptive response, could hold equal significance. Dysfunctional interplays among various cell types in the kidney microenvironment can instigate endMT. Transforming growth factor beta (TGF-beta) signaling, with its downstream activation of canonical/Smad-mediated and non-canonical pathways, has been identified as primary driver of this process. However, non-TGF-beta-mediated pathways involving inflammatory agents and metabolic shifts in intercellular communication within the tissue microenvironment can also trigger endMT. These harmful, maladaptive cell-cell interactions and signaling pathways offer potential targets for therapeutic intervention to impede endMT and decelerate fibrogenesis such as in AKI-CKD progression. Presently, partial reduction of TGF-beta signaling using anti-diabetic drugs or statins may hold therapeutic potential in renal context. Nevertheless, further investigation is warranted to validate underlying mechanisms and assess positive effects within a clinical framework. Show less
Wiersma, L.E.; Avramut, M.C.; Koster, A.J.; Berg, C.W. van den; Rabelink, T.J. 2023
Pluripotent stem cell-derived kidney organoids hold great promise as a potential auxiliary transplant tissue for individuals with end-stage renal disease and as a platform for studying kidney... Show morePluripotent stem cell-derived kidney organoids hold great promise as a potential auxiliary transplant tissue for individuals with end-stage renal disease and as a platform for studying kidney diseases and drug discovery. To establish accurate models, it is crucial to thoroughly characterize the morphological features and maturation stages of the cellular components within these organoids. Nephrons, the functional units of the kidney, possess distinct morphological structures that directly correlate with their specific functions. High spatial resolution imaging emerges as a powerful technique for capturing ultrastructural details that may go unnoticed with other methods such as immunofluorescent imaging and scRNA sequencing. In our study, we have applied software capable of seamlessly stitching virtual slides generated from electron microscopy, resulting in high-definition overviews of tissue slides. With this technology, we can comprehensively characterize the development and maturation of kidney organoids when transplanted under the renal capsule of mice. These organoids exhibit advanced ultrastructural developments upon transplantation, including the formation of the filtration barrier in the renal corpuscle, the presence of microvilli in the proximal tubule, and various types of cell sub-segmentation in the connecting tubule similarly to those seen in the adult kidney. Such ultrastructural characterization provides invaluable insights into the structural development and functional morphology of nephron segments within kidney organoids and how to advance them by interventions such as a transplantation. Research Highlights High-resolution imaging is crucial to determine morphological maturation of hiPSC-derived kidney organoids. Upon transplantation, refined ultrastructural development of nephron segments was observed, such as the development of the glomerular filtration barrier. Show less
Wiersma, L.E.; Avramut, M.C.; Koster, A.J.; Berg, C.W. van den; Rabelink, T.J. 2023
Pluripotent stem cell-derived kidney organoids hold great promise as a potential auxiliary transplant tissue for individuals with end-stage renal disease and as a platform for studying kidney... Show morePluripotent stem cell-derived kidney organoids hold great promise as a potential auxiliary transplant tissue for individuals with end-stage renal disease and as a platform for studying kidney diseases and drug discovery. To establish accurate models, it is crucial to thoroughly characterize the morphological features and maturation stages of the cellular components within these organoids. Nephrons, the functional units of the kidney, possess distinct morphological structures that directly correlate with their specific functions. High spatial resolution imaging emerges as a powerful technique for capturing ultrastructural details that may go unnoticed with other methods such as immunofluorescent imaging and scRNA sequencing. In our study, we have applied software capable of seamlessly stitching virtual slides generated from electron microscopy, resulting in high-definition overviews of tissue slides. With this technology, we can comprehensively characterize the development and maturation of kidney organoids when transplanted under the renal capsule of mice. These organoids exhibit advanced ultrastructural developments upon transplantation, including the formation of the filtration barrier in the renal corpuscle, the presence of microvilli in the proximal tubule, and various types of cell sub-segmentation in the connecting tubule similarly to those seen in the adult kidney. Such ultrastructural characterization provides invaluable insights into the structural development and functional morphology of nephron segments within kidney organoids and how to advance them by interventions such as a transplantation. Show less
Gaykema, L.H.; Nieuwland, R.Y. van; Lievers, E.; Moerkerk, W.B.J.; Klerk, J.A. de; Dumas, S.J.; ... ; Rabelink, T.J. 2023
Immune evasive induced pluripotent stem cell (iPSC)-derived kidney organoids, known as “stealth” organoids, hold promise for clinical transplantation. To address immune rejection, we investigated... Show moreImmune evasive induced pluripotent stem cell (iPSC)-derived kidney organoids, known as “stealth” organoids, hold promise for clinical transplantation. To address immune rejection, we investigated the impact of genetically modifying human leukocyte antigen (HLA) class I in kidney organoids prior to transplantation. By using CRISPR-Cas9, we successfully knocked out beta-2-microglobulin (B2M), resulting in iPSCs devoid of HLA class I surface expression. In vitro, the B2M knockout protected kidney organoids derived from these iPSCs against T-cell rejection. To assess in vivo protection, unmodified (control) and B2M–/– kidney organoids were transplanted into humanized mice engrafted with human peripheral blood mononuclear cells (PBMCs). Successful engraftment of human PBMCs was confirmed, and after 4 weeks, we observed no discernible difference in the infiltration rate, proliferation, or cytotoxicity of CD4+ and CD8+ T cells between control and B2M–/– organoids. Both groups of organoids showed compromised tissue integrity, displaying tubulitis and loss of tubule integrity. Notably, while B2M–/– organoids failed to express HLA class I on their cell surface, there was preexisting expression of HLA class II in both control and B2M–/– organoids transplanted into mice with human PBMCs. HLA class II expression was not limited to antigen-presenting cells but also evident in epithelial cells of the kidney organoid, posing an additional immunological challenge to its transplantation. Consequently, we conclude that B2M knockout alone is insufficient to protect iPSC-derived kidney organoids from T-cell-mediated immune rejection. Additionally, our findings suggest that modulating HLA class II signaling will be necessary to prevent rejection following transplantation. Show less
Heart and kidney communicate with one another in an interdependent relationship and they influence each other's behavior reciprocally, as pathological changes in one organ can damage the other.... Show moreHeart and kidney communicate with one another in an interdependent relationship and they influence each other's behavior reciprocally, as pathological changes in one organ can damage the other. Although independent human in vitro models for heart and kidney exist, they do not capture their dynamic crosstalk. We have developed a microfluidic system which can be used to study heart and kidney interaction in vitro. Cardiac microtissues (cMTs) and kidney organoids (kOs) derived from human induced pluripotent stem cells (hiPSCs) were generated and loaded into two separated communicating chambers of a perfusion chip. Static culture conditions were compared with dynamic culture under unidirectional flow. Tissue viability was maintained for minimally 72 h under both conditions, as indicated by the presence of sarcomeric structures coupled with beating activity in cMTs and the presence of nephron structures and albumin uptake in kOs. We concluded that this system enables the study of human cardiac and kidney organoid interaction in vitro while controlling parameters like fluidic flow speed and direction. Together, this "cardiorenal-unit" provides a new in vitro model to study the cardiorenal axis and it may be further developed to investigate diseases involving both two organs and their potential treatments. Show less
Yuan, L.S.; Han, J.H.; Velden, A.I.M.V.; Vink, H.; Mutsert, R. de; Rosendaal, F.R.; ... ; Berg, B.M. van den 2023
Background: Microvascular dysfunction is a growing determinant of sex differences in coronary heart disease (CHD). Dysregulation of the coagulation system is involved in CHD pathogenesis and can be... Show moreBackground: Microvascular dysfunction is a growing determinant of sex differences in coronary heart disease (CHD). Dysregulation of the coagulation system is involved in CHD pathogenesis and can be induced by endothelial glycocalyx (EG) perturbation. However, little is known about the link between EG function and coagulation parameters in population-based studies on sex specificity.Objectives: We sought to examine the sex differences in the relationship between EG function and coagulation parameters in a middle-aged Dutch population.Methods: Using baseline measurements of 771 participants from the Netherlands Epidemiology of Obesity study (age, 56 years [IQR, 51-61 years]; 53% women; body mass index, 27.9 kg/m2 [IQR, 25.1-30.9 kg/m2 ]), associations between glycocalyxrelated perfused boundary region (PBR) derived using sidestream dark-field imaging and coagulation parameters (factor [F]VIII/IX/XI; thrombin generation parameters; and fibrinogen) were investigated using linear regression analyses, adjusting for possible confounders (including C-reactive protein, leptin, and glycoprotein acetyls), followed by sex-stratified analyses.Results: There was a sex difference in the associations between PBR and coagulation parameters. Particularly in women, 1-SD PBR (both total and feed vessel, indicating poorer glycocalyx status) was associated with higher FIX activity ([1.8%; 95% CI, 0.3%- 3.3%] and [2.0%; 95% CI, 0.5%-3.4%], respectively) and plasma fibrinogen levels ([5.1 mg/dL; 95% CI, 0.4-9.9 mg/dL] and [5.8 mg/dL; 95% CI, 1.1-10.6 mg/dL], respectively). Furthermore, 1-SD PBRcapillary was associated with higher FVIII activity (3.5%; 95% CI, 0.4%-6.5%) and plasma fibrinogen levels (5.3 mg/dL; 95% CI, 0.6-10.0 mg/dL).Conclusion: We revealed a sex-specific association between microcirculatory health and procoagulant status, which suggests that microvascular health be considered during early development of CHD in women. Show less
Background: The glomerular endothelial glycocalyx is degraded during inflammation. The glycocalyx plays a pivotal role in endothelial function and is involved in many processes including binding of... Show moreBackground: The glomerular endothelial glycocalyx is degraded during inflammation. The glycocalyx plays a pivotal role in endothelial function and is involved in many processes including binding of chemokines and cytokines, leukocyte trafficking, and preventing proteinuria. HS-based therapeutics are a promising novel class of anti-inflammatory drugs to restore a compromised endothelial glycocalyx under inflammatory conditions. Recently, we demonstrated that treatment with HS extracted from unstimulated glomerular endothelial glycocalyx (unstimulated HSglx) reduced albuminuria during anti-GBM induced glomerulonephritis. Since endothelial HS domains are distinct in unstimulated versus inflammatory conditions, we hypothesized that 1) unstimulated HSglx, 2) LPS-stimulated HSglx, 3) the HS-mimetic fucoidan and 4) the glycosaminoglycan preparation sulodexide, which is a mixture of low molecular weight heparin and dermatan sulfate, might have different beneficial effects in experimental glomerulonephritis.Methods: The effect of unstimulated HSglx, LPS HSglx, Laminaria japonica fucoidan, or sulodexide on experimental glomerulonephritis was tested in LPS-induced glomerulonephritis in mice. Analyses included urinary albumin creatinine measurement, cytokine expression in plasma and renal cortex, and renal influx of immune cells determined by flow cytometry and immunofluorescence staining. Furthermore, the observed in vivo effects were evaluated in cultured glomerular endothelial cells and peripheral blood mononuclear cells by measuring cytokine and ICAM-1 expression levels. The ability of the compounds to inhibit heparanase activity was assessed in a heparanase activity assay.Results: Treatment of mice with LPS HSglx or sulodexide near-significantly attenuated LPS-induced proteinuria. All treatments reduced plasma MCP-1 levels, whereas only fucoidan reduced IL-6 and IL-10 plasma levels. Moreover, all treatments reversed cortical ICAM-1 mRNA expression and both fucoidan and sulodexide reversed cortical IL-6 and nephrin mRNA expression. Sulodexide decreased renal influx of CD45(+) immune cells whereas renal influx of macrophages and granulocytes remained unaltered for all treatments. Although all compounds inhibited HPSE activity, fucoidan and sulodexide were the most potent inhibitors. Notably, fucoidan and sulodexide decreased LPS-induced mRNA expression of ICAM-1 and IL-6 by cultured glomerular endothelial cells.Conclusion: Our data show a potentially protective effect of glycosaminoglycans and fucoidan in experimental glomerulonephritis. Future research should be aimed at the further identification of defined HS structures that have therapeutic potential in the treatment of glomerular diseases. Show less
Maciej-Hulme, M.L.; Gemst, J.J. van; Sanderson, P.; Rops, A.L.W.M.M.; Berden, J.H.; Smeets, B.; ... ; Vlag, J. van der 2023
Proliferative forms of glomerulonephritis are characterized by the influx of leukocytes, albuminuria, and loss of kidney function. The glomerular endothelial glycocalyx is a thick carbohydrate... Show moreProliferative forms of glomerulonephritis are characterized by the influx of leukocytes, albuminuria, and loss of kidney function. The glomerular endothelial glycocalyx is a thick carbohydrate layer that covers the endothelium and is comprised of heparan sulfate (HS), which plays a pivotal role in glomerular inflammation by facilitating endothelial-leukocyte trafficking. We hypothesize that the exogenous glomerular glycocalyx may reduce the glomerular influx of inflammatory cells during glomerulonephritis. Indeed, administration of mouse glomerular endothelial cell (mGEnC)-derived glycocalyx constituents, or the low-molecular-weight heparin enoxaparin, reduced proteinuria in mice with experimental glomerulonephritis. Glomerular influx of granulocytes and macrophages, as well as glomerular fibrin deposition, was reduced by the administration of mGEnC-derived glycocalyx constituents, thereby explaining the improved clinical outcome. HSglx also inhibited granulocyte adhesion to human glomerular endothelial cells in vitro. Notably, a specific HSglx fraction inhibited both CD11b and L-selectin binding to activated mGEnCs. Mass spectrometry analysis of this specific fraction revealed six HS oligosaccharides, ranging from tetra- to hexasaccharides with 2-7 sulfates. In summary, we demonstrate that exogenous HSglx reduces albuminuria during glomerulonephritis, which is possibly mediated via multiple mechanisms. Our results justify the further development of structurally defined HS-based therapeutics for patients with (acute) inflammatory glomerular diseases, which may be applicable to non-renal inflammatory diseases as well. Show less
Yuan, L.S.; Li-Gao, R.; Verhoeven, A.; Eyk, H.J. van; Bizino, M.B.; Rensen, P.C.N.; ... ; Berg, B.M. van den 2023
Background: Composition of high-density lipoproteins (HDL) is emerging as an important determinant in the development of microvascular complications in type 2 diabetes mellitus (T2DM). Dutch South... Show moreBackground: Composition of high-density lipoproteins (HDL) is emerging as an important determinant in the development of microvascular complications in type 2 diabetes mellitus (T2DM). Dutch South Asian (DSA) individuals with T2DM display an increased risk of microvascular complications compared with Dutch white Caucasian (DwC) individuals with T2DM. In this study, we aimed to investigate whether changes in HDL composition associate with increased microvascular risk in this ethnic group and lead to new lipoprotein biomarkers. Materials and Methods: Using H-1 nuclear magnetic resonance spectroscopy and Bruker IVDr Lipoprotein Subclass Analysis (B.I.LISA) software, plasma lipoprotein changes were determined in 51 healthy individuals (30 DwC, 21 DSA) and 92 individuals with T2DM (45 DwC, 47 DSA) in a cross-sectional, case-control study. Differential HDL subfractions were investigated using multinomial logistic regression analyses, adjusting for possible confounders including BMI and diabetes duration. Results: We identified HDL compositional differences between healthy and diabetic individuals in both ethnic groups. Specifically, levels of apolipoprotein A2 and HDL-4 subfractions were lower in DSA compared with DwC with T2DM. Apolipoprotein A2 and HDL-4 subfractions also negatively correlated with waist circumference, waistto-hip ratio, haemoglobin A1c, glucose levels and disease duration in DSA with T2DM, and associated with increased incidence of microvascular complications .Conclusion: While HDL composition differed between controls and T2DM in both ethnic groups, the lower levels of lipid content in the smallest HDL subclass (HDL-4) in DSA with T2DM appeared to be more clinically relevant, with higher odds of having diabetes-related pan-microvascular complications such as retinopathy and neuropathy. These typical differences in HDL could be used as ethnicity-specific T2DM biomarkers. Show less
Rietjens, R.G.J.; Wang, G.Q.; Velden, A.I.M. van der; Koudijs, A.; Avramut, M.C.; Kooijman, S.; ... ; Berg, B.M. van den 2023
Diabetes is a main risk factor for kidney disease, causing diabetic nephropathy in close to half of all patients with diabetes. Metabolism has recently been identified to be decisive in cell fate... Show moreDiabetes is a main risk factor for kidney disease, causing diabetic nephropathy in close to half of all patients with diabetes. Metabolism has recently been identified to be decisive in cell fate decisions and repair. Here we used mass spectrometry imaging (MSI) to identify tissue specific metabolic dysregulation, in order to better understand early diabetes-induced metabolic changes of renal cell types. In our experimental diabetes mouse model, early glomerular glycocalyx barrier loss and systemic metabolic changes were observed. In addition, MSI targeted at small molecule metabolites and glycero(phospho)lipids exposed distinct changes upon diabetes in downstream nephron segments. Interestingly, the outer stripe of the outer medullar proximal tubular segment (PT_S3) demonstrated the most distinct response compared to other segments. Furthermore, phosphatidylinositol lipid metabolism was altered specifically in PT_S3, with one of the phosphatidylinositol fatty acid tails being exchanged from longer unsaturated fatty acids to shorter, more saturated fatty acids. In acute kidney injury, the PT_S3 segment and its metabolism are already recognized as important factors in kidney repair processes. The current study exposes early diabetes-induced changes in membrane lipid composition in this PT_S3 segment as a hitherto unrecognized culprit in the early renal response to diabetes. Show less
Garsen, M.; Buijsers, B.; Sol, M.; Gockeln, L.; Sonneveld, R.; Kuppevelt, T.H. van; ... ; Vlag, J. van der 2023
Background Proteinuria is associated with many glomerular diseases and a risk factor for the progression to renal failure. We previously showed that heparanase (HPSE) is essential for the... Show moreBackground Proteinuria is associated with many glomerular diseases and a risk factor for the progression to renal failure. We previously showed that heparanase (HPSE) is essential for the development of proteinuria, whereas peroxisome proliferator-activated receptor y (PPARy) agonists can ameliorate proteinuria. Since a recent study showed that PPARy regulates HPSE expression in liver cancer cells, we hypothesized that PPARy agonists exert their reno-protective effect by inhibiting glomerular HPSE expression.Methods Regulation of HPSE by PPARy was assessed in the adriamycin nephropathy rat model, and cultured glomerular endothelial cells and podocytes. Analyses included immunofluorescence staining, real-time PCR, heparanase activity assay and transendothelial albumin passage assay. Direct binding of PPARy to the HPSE promoter was evaluated by the luciferase reporter assay and chromatin immunoprecipitation assay. Furthermore, HPSE activity was assessed in 38 type 2 diabetes mellitus (T2DM) patients before and after 16/24 weeks treatment with the PPARy agonist pioglitazone.Findings Adriamycin-exposed rats developed proteinuria, an increased cortical HPSE and decreased heparan sulfate (HS) expression, which was ameliorated by treatment with pioglitazone. In line, the PPARy antagonist GW9662 increased cortical HPSE and decreased HS expression, accompanied with proteinuria in healthy rats, as previously shown. In vitro, GW9662 induced HPSE expression in both endothelial cells and podocytes, and increased trans -endothelial albumin passage in a HPSE-dependent manner. Pioglitazone normalized HPSE expression in adriamycin-injured human endothelial cells and mouse podocytes, and adriamycin-induced transendothelial albumin passage was reduced as well. Importantly, we demonstrated a regulatory effect of PPARy on HPSE promoter activity and direct PPARy binding to the HPSE promoter region. Plasma HPSE activity of T2DM patients treated with pioglitazone for 16/24 weeks was related to their hemoglobin A1c and showed a moderate, near significant correlation with plasma creatinine levels.Interpretation PPARy-mediated regulation of HPSE expression appears an additional mechanism explaining the anti-proteinuric and renoprotective effects of thiazolidinediones in clinical practice.Copyright (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Show less
Koning, M.; Lievers, E.; Jaffredo, T.; Berg, C.W. van den; Rabelink, T.J. 2023
Kidney organoids derived from human induced pluripotent stem cells contain nephron-like structures that resemble those in the adult kidney to a certain degree. Unfortunately, their clinical... Show moreKidney organoids derived from human induced pluripotent stem cells contain nephron-like structures that resemble those in the adult kidney to a certain degree. Unfortunately, their clinical applicability is hampered by the lack of a functional vasculature and consequently limited maturation in vitro. The transplantation of kidney organoids in the celomic cavity of chicken embryos induces vascularization by perfused blood vessels, including the formation of glomerular capillaries, and enhances their maturation. This technique is very efficient, allowing for the transplantation and analysis of large numbers of organoids. This paper describes a detailed protocol for the intracelomic transplantation of kidney organoids in chicken embryos, followed by the injection of fluorescently labeled lectin to stain the perfused vasculature, and the collection of transplanted organoids for imaging analysis. This method can be used to induce and study organoid vascularization and maturation to find clues for enhancing these processes in vitro and improve disease modeling. Show less
Gaykema, L.H.; Nieuwland, R.Y. van; Dekkers, M.C.; Essen, M.F. van; Heidt, S.; Zaldumbide, A.; ... ; Kooten, C. van 2023
End stage renal disease is an increasing problem worldwide driven by aging of the population and increased prevalence of metabolic disorders and cardiovascular disease. Currently, kidney... Show moreEnd stage renal disease is an increasing problem worldwide driven by aging of the population and increased prevalence of metabolic disorders and cardiovascular disease. Currently, kidney transplantation is the only curative option, but donor organ shortages greatly limit its application. Regenerative medicine has the potential to solve the shortage by using stem cells to grow the desired tissues, like kidney tissue. Immune rejection poses a great threat towards the implementation of stem cell derived tissues and various strategies have been explored to limit the immune response towards these tissues. However, these studies are limited by targeting mainly T cell mediated immune rejection while the rejection process also involves innate and humoral immunity. In this study we investigate whether inhibition of the complement system in human induced pluripotent stem cells (iPSC) could provide protection from such immune injury. To this end we created knock-in iPSC lines of the membrane bound complement inhibitor CD55 to create a transplant-specific protection towards complement activation. CD55 inhibits the central driver of the complement cascade, C3 convertase, and we show that overexpression is able to decrease complement activation on both iPSCs as well as differentiated kidney organoids upon stimulation with anti-HLA antibodies to mimic the mechanism of humoral rejection. Show less
Background: This study investigated the clinical value of adding the sFlt-1/PlGF ratio to the spot urine protein/creatinine ratio (PCr) in women with suspected pre-eclampsia. Methods: This was a... Show moreBackground: This study investigated the clinical value of adding the sFlt-1/PlGF ratio to the spot urine protein/creatinine ratio (PCr) in women with suspected pre-eclampsia. Methods: This was a prospective cohort study performed in a tertiary referral centre. Based on the combination of PCr (< 30) and sFlt-1/PlGF (& LE;38) results, four groups were described: a double negative result, group A-/-; a negative PCr and positive sFlt-1/PlGF, group B-/+; a positive PCr and negative sFlt-1/PlGF, group C+/-; and a double positive result, group D+/+. The primary outcome was the proportion of false negatives of the combined tests in comparison with PCr alone in the first week after baseline. Secondary, a cost analysis comparing the costs and savings of adding the sFlt-1/PlGF ratio was performed for different follow-up scenarios. Results: A total of 199 women were included. Pre-eclampsia in the first week was observed in 2 women (2%) in group A-/-, 12 (26%) in group B-/+, 4 (27%) in group C+/-, and 12 (92%) in group D+/+. The proportion of false negatives of 8.2% [95% CI 4.9-13.3] with the PCr alone was significantly reduced to 1.6% [0.4-5.7] by adding a negative sFlt-1/PlGF ratio. Furthermore, the addition of the sFlt-1/PlGF ratio to the spot urine PCr, with telemonitoring of women at risk, could result in a reduction of 41% admissions and 36% outpatient visits, leading to a cost reduction of euro46,- per patient. Conclusions: Implementation of the sFlt-1/PlGF ratio in addition to the spot urine PCr, may lead to improved selection of women at low risk and a reduction of hospital care for women with suspected pre-eclampsia. Show less
