Mitochondrial dysfunction is the most prominent source of oxidative stress in acute and chronic kidney disease. NLRX1 is a receptor of the innate immune system that is ubiquitously expressed and ...localized in mitochondria. We investigated whether NLRX1 may act at the interface of metabolism and innate immunity in a model of oxidative stress. Using a chimeric mouse model for renal ischemia-reperfusion injury, we found that NLRX1 protects against mortality, mitochondrial damage, and epithelial cell apoptosis in an oxidative stress-dependent fashion. We found that NLRX1 regulates oxidative phosphorylation and cell integrity, whereas loss of NLRX1 results in increased oxygen consumption, oxidative stress, and subsequently apoptosis in epithelial cells during ischemia-reperfusion injury. In line, we found that NLRX1 expression in human kidneys decreased during acute renal ischemic injury and acute cellular rejection. Although first implicated in immune regulation, we propose that NLRX1 function extends to the control of mitochondrial activity and prevention of oxidative stress and apoptosis in tissue injury.
Background: Organohalogen compounds (OHCs) are known to have neurotoxic effects on the developing brain. Objective: We investigated the influence of prenatal exposure to OHCs, including brominated ...flame retardants, on motor, cognitive, and behavioral outcome in healthy children of school age. Methods: This study was part of the prospective Groningen infant COMPARE (Comparison of Exposure-Effect Pathways to Improve the Assessment of Human Health Risks of Complex Environmental Mixtures of Organohalogens) study. It included 62 children in whose mothers the following compounds had been determined in the 35th week of pregnancy: 2,2'-bis-(4 chlorophenyl)1,1'-dichloroethene, pentachlorophenol (PCP), polychlorinated biphenyl congener 153 (PCB-153), 4-hydroxy-2,3,3',4',5-pentachlorobiphenyl (40H-CB-107), 40H-CB-146, 40H-CB-187, 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), BDE-99, BDE-100, BDE-153, BDE-154, and hexabromocyclododecane. Thyroid hormones were determined in umbilical cord blood. When the children were 5-6 years of age, we assessed their neuropsychological functioning: motor performance (coordination, fine motor skills), cognition (intelligence, visual perception, visuomotor integration, inhibitory control, verbal memory, and attention), and behavior. Results: Brominated flame retardants correlated with worse fine manipulative abilities, worse attention, better coordination, better visual perception, and better behavior. Chlorinated OHCs correlated with less choreiform dyskinesia. Hydroxylated polychlorinated biphenyls correlated with worse fine manipulative abilities, better attention, and better visual perception. The wood protective agent (PCP) correlated with worse coordination, less sensory integrity, worse attention, and worse visuomotor integration. Conclusions: Our results demonstrate for the first time that transplacental transfer of polybrominated flame retardants is associated with the development of children at school age. Because of the widespread use of these compounds, especially in the United States, where concentrations in the environment are four times higher than in Europe, these results cause serious concern.
Metabolic syndrome (MetSyn) is a major health concern and associates with the development of kidney disease. The mechanisms linking MetSyn to renal disease have not been fully elucidated but are ...known to involve hyperuricemia, inflammation, and fibrosis. Since the innate immune receptor Nlrp3 is an important mediator of obesity and inflammation, we sought to determine whether Nlrp3 is involved in the development of MetSyn-associated nephropathy by giving wild-type or Nlrp3-knockout mice a Western-style compared to a normal diet or water without or with fructose. A plausible driver of pathology, the Nlrp3-dependent cytokine IL-1β was not increased in the kidney. Interestingly, Nlrp3-dependent renal cholesterol accumulation, another well-known driver of renal pathology, was enhanced during MetSyn. We also determined the role of Nlrp3 and fructose-fortified water on the development of MetSyn and kidney function since fructose is an important driver of obesity and kidney disease. Surprisingly, fructose did not induce MetSyn but, irrespective of this, did induce Nlrp3-dependent renal inflammation. The presence of Nlrp3 was crucial for the development of Western-style diet–induced renal pathology as reflected by the prevention of renal inflammation, fibrosis, steatosis, microalbuminuria, and hyperuricemia in the Nlrp3-knockout mice. Thus, Nlrp3 may mediate renal pathology in the context of diet-induced MetSyn.
Ischemia/reperfusion injury is a major cause of acute kidney injury. Improving renal repair would represent a therapeutic strategy to prevent renal dysfunction. The innate immune receptor Nlrp3 is ...involved in tissue injury, inflammation, and fibrosis; however, its role in repair after ischemia/reperfusion is unknown. We address the role of Nlrp3 in the repair phase of renal ischemia/reperfusion and investigate the relative contribution of leukocyte- versus renal-associated Nlrp3 by studying bone marrow chimeric mice. We found that Nlrp3 expression was most profound during the repair phase. Although Nlrp3 expression was primarily expressed by leukocytes, both leukocyte- and renal-associated Nlrp3 was detrimental to renal function after ischemia/reperfusion. The Nlrp3-dependent cytokine IL-1β remained unchanged in kidneys of all mice. Leukocyte-associated Nlrp3 negatively affected tubular apoptosis in mice that lacked Nlrp3 expression on leukocytes, which correlated with reduced macrophage influx. Nlrp3-deficient ( Nlrp3KO ) mice with wild-type bone marrow showed an improved repair response, as seen by a profound increase in proliferating tubular epithelium, which coincided with increased hepatocyte growth factor expression. In addition, Nlrp3KO tubular epithelial cells had an increased repair response in vitro , as seen by an increased ability of an epithelial monolayer to restore its structural integrity. In conclusion, Nlrp3 shows a tissue-specific role in which leukocyte-associated Nlrp3 is associated with tubular apoptosis, whereas renal-associated Nlrp3 impaired wound healing.
Background and Objective
Historically, dosing of tacrolimus is guided by therapeutic drug monitoring (TDM) of the whole blood concentration, which is strongly influenced by haematocrit. The ...therapeutic and adverse effects are however expected to be driven by the unbound exposure, which could be better represented by measuring plasma concentrations.
Objective
We aimed to establish plasma concentration ranges reflecting whole blood concentrations within currently used target ranges.
Methods
Plasma and whole blood tacrolimus concentrations were determined in samples of transplant recipients included in the TransplantLines Biobank and Cohort Study. Targeted whole blood trough concentrations are 4–6 ng/mL and 7–10 ng/mL for kidney and lung transplant recipients, respectively. A population pharmacokinetic model was developed using non-linear mixed-effects modelling. Simulations were performed to infer plasma concentration ranges corresponding to whole blood target ranges.
Results
Plasma (
n
= 1973) and whole blood (
n
= 1961) tacrolimus concentrations were determined in 1060 transplant recipients. A one-compartment model with fixed first-order absorption and estimated first-order elimination characterised observed plasma concentrations. Plasma was linked to whole blood using a saturable binding equation (maximum binding 35.7 ng/mL, 95% confidence interval (CI) 31.0–40.4 ng/mL; dissociation constant 0.24 ng/mL, 95% CI 0.19–0.29 ng/mL). Model simulations indicate that patients within the whole blood target range are expected to have plasma concentrations (95% prediction interval) of 0.06–0.26 ng/mL and 0.10–0.93 ng/mL for kidney and lung transplant recipients, respectively.
Conclusion
Whole blood tacrolimus target ranges, currently used to guide TDM, were translated to plasma concentration ranges of 0.06–0.26 ng/mL and 0.10–0.93 ng/mL for kidney and lung transplant recipients, respectively.
Ischemia reperfusion injury is a common cause of acute kidney injury and is characterized by tubular damage. Mitochondrial DNA is released upon severe tissue injury and can act as a damage-associated ...molecular pattern via the innate immune receptor TLR9. Here, we investigated the role of TLR9 in the context of moderate or severe renal ischemia reperfusion injury using wild-type C57BL/6 mice or TLR9KO mice. Moderate renal ischemia induced renal dysfunction but did not decrease animal well-being and was not regulated by TLR9. In contrast, severe renal ischemia decreased animal well-being and survival in wild-type mice after respectively one or five days of reperfusion. TLR9 deficiency improved animal well-being and survival. TLR9 deficiency did not reduce renal inflammation or tubular necrosis. Rather, severe renal ischemia induced hepatic injury as seen by increased plasma ALAT and ASAT levels and focal hepatic necrosis which was prevented by TLR9 deficiency and correlated with reduced circulating mitochondrial DNA levels and plasma LDH. We conclude that TLR9 does not mediate renal dysfunction following either moderate or severe renal ischemia. In contrast, our data indicates that TLR9 is an important mediator of hepatic injury secondary to ischemic acute kidney injury.
The collateral effects of obesity/metabolic syndrome include inflammation and renal function decline. As renal disease in obesity can occur independently of hypertension and diabetes, other yet ...undefined causal pathological pathways must be present. Our study elucidate novel pathological pathways of metabolic renal injury through LDL-induced lipotoxicity and metainflammation. Our in vitro and in vivo analysis revealed a direct lipotoxic effect of metabolic overloading on tubular renal cells through a multifaceted mechanism that includes intralysosomal lipid amassing, lysosomal dysfunction, oxidative stress, and tubular dysfunction. The combination of these endogenous metabolic injuries culminated in the activation of the innate immune NLRP3 inflammasome complex. By inhibiting the sirtuin-1/LKB1/AMPK pathway, NLRP3 inflammasome dampened lipid breakdown, thereby worsening the LDL-induced intratubular phospholipid accumulation. Consequently, the presence of NLRP3 exacerbated tubular oxidative stress, mitochondrial damage and malabsorption during overnutrition. Altogether, our data demonstrate a causal link between LDL and tubular damage and the creation of a vicious cycle of excessive nutrients-NLRP3 activation-catabolism inhibition during metabolic kidney injury. Hence, this study strongly highlights the importance of renal epithelium in lipid handling and recognizes the role of NLRP3 as a central hub in metainflammation and immunometabolism in parenchymal non-immune cells.
INTRODUCTION
We investigated whether mortality in memory clinic patients changed due to coronavirus disease 2019 (COVID‐19) pandemic.
METHODS
We included patients from the Amsterdam Dementia Cohort: ...(1) n = 923 pandemic patients (baseline visit: 2017–2018, follow‐up: until 2021), and (2) n = 830 historical control patients (baseline visit: 2015–2016, follow‐up: until 2019). Groups were well‐balanced. We compared mortality during pandemic with historical control patients using Cox regression. Differences in cause of death between groups were explored using Fisher's exact test.
RESULTS
Pandemic patients had a higher risk of mortality than historical control patients (hazard ratio HR 95% confidence interval {CI} = 1.34 1.05–1.70). Stratified for syndrome diagnosis, the effect remained significant in dementia patients (HR 95% CI = 1.35 1.03–1.78). Excluding patients who died of COVID‐19‐infection, the higher mortality risk in pandemic patients attenuated (HR 95% CI = 1.24 0.97–1.58). Only the difference in cause of death between pandemic patients and historical control patients for death to COVID‐19‐infection (p = 0.001) was observed.
CONCLUSION
Memory clinic patients had increased mortality risk during COVID‐19 compared to historical control patients, attributable to dementia patients.
Highlights
We investigated if mortality rates in memory clinic patients changed due to COVID‐19 pandemic.
We included patients along the cognitive continuum, including SCD, MCI, and dementia.
We used a well‐balanced historical control group.
Memory clinic patients had higher risk for mortality during COVID‐19 lockdown.
Our results indicate that excess mortality is mainly caused by death to COVID‐19 infection.
Epithelial to mesenchymal transition (EMT) is typically defined by the acquisition of a spindle cell morphology in combination with loss of E-cadherin and upregulation of mesenchymal markers. ...However, by studying E-cadherin inactivation in 38 human breast cancer cell lines, we noted that not all cell lines that had undergone EMT had concomitantly lost E-cadherin expression. We further investigated this discrepancy functionally and in clinical breast cancer specimens. Interestingly, reconstitution of wild-type
E
-
cadherin
cDNA in a E-cadherin negative cell line that had undergone EMT (MDA-MB-231) did not revert the spindle morphology back to an epithelial morphology. Neither were changes observed in the expression of several markers known to be involved in the EMT process. Similarly, upregulation of E-cadherin via global DNA demethylation in eleven cell lines that had undergone EMT did not induce a change in cell morphology, nor did it alter the expression of EMT markers in these cells. Next, we extracted genes differentially expressed between cell lines that had undergone EMT versus cell lines that had not undergone EMT. Caveolin-1 was identified to be an excellent marker for EMT, irrespective of E-cadherin status (specificity and sensitivity of 100 %). Consistent with our observations in the breast cancer cell lines, expression of Caveolin-1 identified a subset of basal breast cancers, particularly of metaplastic pathology, and only 50 % of these lacked E-cadherin expression. The discrepancy between E-cadherin loss and EMT was thus reproduced in clinical samples. Together, these results indicate that in human breast cancer loss of E-cadherin is not causal for EMT and even not a necessity.
Immune-modulating drugs that target myeloid-derived suppressor cells or stimulate natural killer T cells have been shown to reduce mycobacterial loads in tuberculosis (TB). We aimed to determine if a ...combination of these drugs as adjunct immunotherapy to conventional antibiotic treatment could also increase therapeutic efficacy against TB. In our model of pulmonary TB in mice, we applied treatment with isoniazid, rifampicin, and pyrazinamide for 13 weeks alone or combined with immunotherapy consisting of all-trans retinoic acid, 1,25(OH)
-vitamin D3, and α-galactosylceramide. Outcome parameters were mycobacterial load during treatment (therapeutic activity) and 13 weeks after termination of treatment (therapeutic efficacy). Moreover, cellular changes were analyzed using flow cytometry and cytokine expression was assessed at the mRNA and protein levels. Addition of immunotherapy was associated with lower mycobacterial loads after 5 weeks of treatment and significantly reduced relapse of disease after a shortened 13-week treatment course compared with antibiotic treatment alone. This was accompanied by reduced accumulation of immature myeloid cells in the lungs at the end of treatment and increased TNF-α protein levels throughout the treatment period. We demonstrate, in a mouse model of pulmonary TB, that immunotherapy consisting of three clinically approved drugs can improve the therapeutic efficacy of standard antibiotic treatment.
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