Kidney Ischemia/Reperfusion Injury Induces Changes in the Drug Transporter Expression at the Blood-Brain Barrier in vivo and in vitro
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Updated: Nov 27, 2025
Technical Refinement of a Bilateral Renal Ischemia-Reperfusion Mouse Model for Acute Kidney Injury Research
Published on: November 3, 2023
Malgorzata Burek1, Sandra Burmester1, Ellaine Salvador1
1Department of Anaesthesia and Critical Care, University of Würzburg, Würzburg, Germany.
Abstract:
Ischemia/reperfusion injury is a major cause of acute kidney injury (AKI). AKI is characterized by a sudden decrease in kidney function, systemic inflammation, oxidative stress, and dysregulation of the sodium, potassium, and water channels. While AKI leads to uremic encephalopathy, epidemiological studies have shown that AKI is associated with a subsequent risk for developing stroke and dementia. To get more insights into kidney-brain crosstalk, we have created an in vitro co-culture model based on human kidney cells of the proximal tubule (HK-2) and brain microvascular endothelial cells (BMEC). The HK-2 cell line was grown to confluence on 6-well plates and exposed to oxygen/glucose deprivation (OGD) for 4 h. Control HK-2 cells were grown under normal conditions. The BMEC cell line cerebED was grown to confluence on transwells with 0.4 μm pores. The transwell filters seeded and grown to confluence with cereEND were inserted into the plates with HK-2 cells with or without OGD treatment. In addition, cerebEND were left untreated or treated with uremic toxins, indole-3-acetic acid (IAA) and indoxyl sulfate (IS). The protein and mRNA expression of selected BBB-typical influx transporters, efflux transporters, cellular receptors, and tight junction proteins was measured in BMECs. To validate this in vitro model of kidney-brain interaction, we isolated brain capillaries from mice exposed to bilateral renal ischemia (30 min)/reperfusion injury (24 h) and measured mRNA and protein expression as described above. Both in vitro and in vivo systems showed similar changes in the expression of drug transporters, cellular receptors, and tight junction proteins. Efflux pumps, in particular Abcb1b, Abcc1, and Abcg2, have shown increased expression in our model. Thus, our in vitro co-culture system can be used to study the cellular mechanism of kidney and brain crosstalk in renal ischemia/reperfusion injury.
Insights
This study developed an in vitro model to investigate kidney-brain interactions during ischemia/reperfusion injury. The model revealed changes in drug transporters and tight junction proteins, offering insights into acute kidney injury complications.
Area of Science:
- Nephrology
- Neurology
- Cell Biology
Background:
- Ischemia/reperfusion injury is a primary cause of acute kidney injury (AKI), leading to systemic inflammation and oxidative stress.
- AKI is linked to neurological complications like uremic encephalopathy, stroke, and dementia, highlighting the critical kidney-brain crosstalk.
- Understanding the molecular mechanisms of this kidney-brain interaction is crucial for developing effective therapeutic strategies.
Purpose of the Study:
- To establish and validate an in vitro co-culture model simulating kidney-brain crosstalk in the context of ischemia/reperfusion injury.
- To investigate the expression changes of drug transporters, cellular receptors, and tight junction proteins in brain microvascular endothelial cells (BMECs) under simulated AKI conditions.
- To compare the findings from the in vitro model with an in vivo mouse model of renal ischemia/reperfusion injury.
Main Methods:
- Co-culture of human kidney proximal tubule cells (HK-2) and mouse brain microvascular endothelial cells (BMECs) under oxygen/glucose deprivation (OGD) or uremic toxin exposure.
- Measurement of protein and mRNA expression of key transporters and tight junction proteins in BMECs.
- Validation using brain capillaries isolated from mice subjected to renal ischemia/reperfusion injury.
Main Results:
- The in vitro co-culture model successfully mimicked key molecular changes observed in the in vivo model.
- Significant alterations in the expression of drug transporters, cellular receptors, and tight junction proteins were detected in BMECs.
- Notably, increased expression of efflux pumps, including Abcb1b, Abcc1, and Abcg2, was observed in the model.
Conclusions:
- The developed in vitro co-culture system serves as a valuable tool for studying kidney-brain crosstalk mechanisms.
- This model can elucidate cellular pathways involved in AKI-associated neurological complications.
- Findings highlight the role of altered transporter expression in the blood-brain barrier during renal ischemia/reperfusion injury.
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