Dose and timing of injections for effective cyclosporine A pretreatment before renal ischemia reperfusion in mice

Combination of Deferoxamine With Cyclosporine Synergistically Blunt Renal Cold Ischemia-Reperfusion Injury in Rat Transplantation Model

OBJECTIVES

Ferroptosis plays a pivotal role in the pathogenesis of renal ischemia-reperfusion injury, where the processes are mediated by free ferrous ions and mitochondrial-released reactive oxygen species. However, the administration of high doses of cyclosporine A (CsA) or deferoxamine (DFO) poses a significant risk of renotoxicity. In contrast, low doses of DFO act as a ferrous iron chelator, and CsA functions as a mitochondrial reactive oxygen species blocker. This study aims to explore the potential protective effects of donor treatment with low-dose CsA, DFO, or their combination against ischemia-reperfusion injury during renal transplantation in a rat model.

MATERIALS AND METHODS

In an ex vivo cold storage (CS) model utilizing renal slices, the impact of incorporating DFO, CsA, and a combination of both into the University of Wisconsin solution was assessed through the measurement of lactate dehydrogenase leakage. Additionally, their potential benefits were investigated in a rat donation after circulatory death (DCD) kidney transplant model, where the extent of damage was evaluated based on graft function, tubular necrosis, and inflammation.

RESULTS

The co-administration of DFO and CsA effectively decreased the release of lactate dehydrogenase induced by CS ( P ≥ .05). In the in vivo model, this combined supplementation demonstrated a mitigating effect on reperfusion injury, evidenced by lower blood urea nitrogen levels and acute tubular necrosis scores compared to the control group (allP ≤ .05). Furthermore, the combined treatment significantly reduced apoptotic levels compared to the control group (P ≥ .05).

CONCLUSIONS

The combined treatment with DFO and CsA mitigated the cold ischemia-reperfusion injury in the DCD kidney. Hence, this presents a new strategy for the CS of DCD kidney in clinical transplants.

Ginsenoside Re protects against kainate-induced neurotoxicity in mice by attenuating mitochondrial dysfunction through activation of the signal transducers and activators of transcription 3 signaling

It was demonstrated that ginsenosides exert anti-convulsive potentials and interleukin-6 (IL-6) is protective from excitotoxicity induced by kainate (KA), a model of temporal lobe epilepsy. Ginsenosides-mediated mitochondrial recovery is essential for attenuating KA-induced neurotoxicity, however, little is known about the effects of ginsenoside Re (GRe), one of the major ginsenosides. In this study, GRe significantly attenuated KA-induced seizures in mice. KA-induced redox changes were more evident in mitochondrial fraction than in cytosolic fraction in the hippocampus of mice. GRe significantly attenuated KA-induced mitochondrial oxidative stress (i.e. increases in reactive oxygen species, 4-hydroxynonenal, and protein carbonyl) and mitochondrial dysfunction (i.e. the increase in intra-mitochondrial Ca2+ and the decrease in mitochondrial membrane potential). GRe or mitochondrial protectant cyclosporin A restored phospho-signal transducers and activators of transcription 3 (STAT3) and IL-6 levels reduced by KA, and the effects of GRe were reversed by the JAK2 inhibitor AG490 and the mitochondrial toxin 3-nitropropionic acid (3-NP). Thus, we used IL-6 knockout (KO) mice to investigate whether the interaction between STAT3 and IL-6 is involved in the GRe effects. Importantly, KA-induced reduction of manganese superoxide dismutase (SOD-2) levels and neurodegeneration (i.e. astroglial inhibition, microglial activation, and neuronal loss) were more prominent in IL-6 KO than in wild-type (WT) mice. These KA-induced detrimental effects were attenuated by GRe in WT and, unexpectedly, IL-6 KO mice, which were counteracted by AG490 and 3-NP. Our results suggest that GRe attenuates KA-induced neurodegeneration via modulating mitochondrial oxidative burden, mitochondrial dysfunction, and STAT3 signaling in mice.

A New Approach for Preparing Stable High-Concentration Peptide Nanoparticle Formulations

The subcutaneous administration of therapeutic peptides would provide significant benefits to patients. However, subcutaneous injections are limited in dosing volume, potentially resulting in high peptide concentrations that can incur significant challenges with solubility limitations, high viscosity, and stability liabilities. Herein, we report on the discovery that low-shear resonant acoustic mixing can be used as a general method to prepare stable nanoparticles of a number of peptides of diverse molecular weights and structures in water without the need for extensive amounts of organic solvents or lipid excipients. This approach avoids the stability issues observed with typical high-shear, high-intensity milling methods. The resultant peptide nanosuspensions exhibit low viscosity even at high concentrations of >100 mg/mL while remaining chemically and physically stable. An example nanosuspension of cyclosporine nanoparticles was dosed in rats via a subcutaneous injection and exhibited sustained release behavior. This suggests that peptide nanosuspension formulations can be one approach to overcome the challenges with high-concentration peptide formulations.

From Physiology to Pathology: The Role of Mitochondria in Acute Kidney Injuries and Chronic Kidney Diseases

Background

Renal diseases remain an increasing public health issue affecting millions of people. The kidney is a highly energetic organ that is rich in mitochondria. Numerous studies have demonstrated the important role of mitochondria in maintaining normal kidney function and in the pathogenesis of various renal diseases, including acute kidney injuries (AKIs) and chronic kidney diseases (CKDs).

Summary

Under physiological conditions, fine-tuning mitochondrial energy balance, mitochondrial dynamics (fission and fusion processes), mitophagy, and biogenesis maintain mitochondrial fitness. While under AKI and CKD conditions, disruption of mitochondrial energy metabolism leads to increased oxidative stress. In addition, mitochondrial dynamics shift to excessive mitochondrial fission, mitochondrial autophagy is impaired, and mitochondrial biogenesis is also compromised. These mitochondrial injuries regulate renal cellular functions either directly or indirectly. Mitochondria-targeted approaches, containing genetic (microRNAs) and pharmaceutical methods (mitochondria-targeting antioxidants, mitochondrial permeability pore inhibitors, mitochondrial fission inhibitors, and biogenesis activators), are emerging as important therapeutic strategies for AKIs and CKDs.

Key Messages

Mitochondria play a critical role in the pathogenesis of AKIs and CKDs. This review provides an updated overview of mitochondrial homeostasis under physiological conditions and the involvement of mitochondrial dysfunction in renal diseases. Finally, we summarize the current status of mitochondria-targeted strategies in attenuating renal diseases.

Ginsenoside Re blocks Bay k-8644-induced neurotoxicity via attenuating mitochondrial dysfunction and PKCδ activation in the hippocampus of mice: Involvement of antioxidant potential

Although the anticonvulsant effects of ginsenosides are recognized, little is known about their effects on the convulsive behaviors induced by the activation of L-type Ca²⁺ channels. Here, we investigated whether ginsenoside Re (GRe) modulates excitotoxicity induced by the L-type Ca²⁺ channel activator Bay k-8644. GRe significantly attenuated Bay k-8644-induced convulsive behaviors and hippocampal oxidative stress in mice. GRe-mediated antioxidant potential was more pronounced in the mitochondrial fraction than cytosolic fraction. As L-type Ca²⁺ channels are thought to be targets of protein kinase C (PKC), we investigated the role of PKC under excitotoxic conditions. GRe attenuated Bay k-8644-induced mitochondrial dysfunction, PKCδ activation, and neuronal loss. The PKCδ inhibition and neuroprotection mediated by GRe were comparable to those by the ROS inhibitor N-acetylcysteine, the mitochondrial protectant cyclosporin A, the microglial inhibitor minocycline, or the PKCδ inhibitor rottlerin. Consistently, the GRe-mediated PKCδ inhibition and neuroprotection were counteracted by the mitochondrial toxin 3-nitropropionic acid or the PKC activator bryostatin-1. GRe treatment did not have additional effects on PKCδ gene knockout-mediated neuroprotection, suggesting that PKCδ is a molecular target of GRe. Collectively, our results suggest that GRe-mediated anticonvulsive/neuroprotective effects require the attenuation of mitochondrial dysfunction and altered redox status and inactivation of PKCδ.

Heat Shock Protein 70 Is Involved in the Efficiency of Preconditioning with Cyclosporine A in Renal Ischemia Reperfusion Injury by Modulating Mitochondrial Functions

Cyclosporine A (CsA) preconditioning is known to target mitochondrial permeability transition pore and protect renal function after ischemia reperfusion (IR). The upregulation of heat-shock protein 70 (Hsp70) expression after CsA injection is thought to be associated with renal protection. The aim of this study was to test the effect of Hsp70 expression on kidney and mitochondria functions after IR. Mice underwent a right unilateral nephrectomy and 30 min of left renal artery clamping, performed after CsA injection and/or administration of the Hsp70 inhibitor. Histological score, plasma creatinine, mitochondrial calcium retention capacity, and oxidative phosphorylation were assessed after 24 h of reperfusion. In parallel, we used a model of hypoxia reoxygenation on HK2 cells to modulate Hsp70 expression using an SiRNA or a plasmid. We assessed cell death after 18 h of hypoxia and 4 h of reoxygenation. CsA significantly improved renal function, histological score, and mitochondrial functions compared to the ischemic group but the inhibition of Hsp70 repealed the protection afforded by CsA injection. In vitro, Hsp70 inhibition by SiRNA increased cell death. Conversely, Hsp70 overexpression protected cells from the hypoxic condition, as well as the CsA injection. We did not find a synergic association between Hsp70 expression and CsA use. We demonstrated Hsp70 could modulate mitochondrial functions to protect kidneys from IR. This pathway may be targeted by drugs to provide new therapeutics to improve renal function after IR.

Reassessment of mitochondrial cyclophilin D as a target for improving cardiac arrest outcomes in the era of therapeutic hypothermia

Uncertainty exists regarding whether cyclophilin D (CypD), a mitochondrial matrix protein that plays a key role in ischemia-reperfusion injury, can be a pharmacological target for improving outcomes after cardiac arrest (CA), especially when therapeutic hypothermia is used. Using CypD knockout mice (CypD-/-), we investigated the effects of loss of CypD on short-term and medium-term outcomes after CA. CypD-/- mice or their wild-type (WT) littermates underwent either 5 minute CA followed by resuscitation with and/or without hypothermia at 33°C-34°C (targeted temperature reached within minutes after resuscitation), or a sham procedure. Brain and cardiac injury were assessed using echocardiography, neurological scores, MRI and biomarkers. Seven day survival was compared using Kaplan-Meier estimates. The rate of restoration of spontaneous circulation was significantly higher in CypD-/- mice (with shorter cardiac massage duration) than in WT mice (P < 0.05). Loss of CypD significantly attenuated CA-induced release of troponin and S100ß protein, and limited myocardial dysfunction at 150 minutes after CA. Loss of CypD combined with hypothermia led to the best neurological and MRI scores at 24 hours and highest survival rates at 7 days compared to other groups (P < 0.05). In animals successfully resuscitated, loss of CypD had no benefits on day 7 survival while hypothermia was highly protective. Pharmacological inhibition of CypD with cyclosporine A combined with hypothermia provided similar day 7 survival than loss of CypD combined with hypothermia. CypD is a viable target to improve success of cardiopulmonary resuscitation but its inhibition is unlikely to improve long-term outcomes, unless therapeutic hypothermia is associated.

Mild Therapeutic Hypothermia Protects from Acute and Chronic Renal Ischemia-Reperfusion Injury in Mice by Mitigated Mitochondrial Dysfunction and Modulation of Local and Systemic Inflammation

Renal ischemia-reperfusion (IR) injury can lead to acute kidney injury, increasing the risk of developing chronic kidney disease. We hypothesized that mild therapeutic hypothermia (mTH), 34 °C, applied during ischemia could protect the function and structure of kidneys against IR injuries in mice. In vivo bilateral renal IR led to an increase in plasma urea and acute tubular necrosis at 24 h prevented by mTH. One month after unilateral IR, kidney atrophy and fibrosis were reduced by mTH. Evaluation of mitochondrial function showed that mTH protected against IR-mediated mitochondrial dysfunction at 24 h, by preserving CRC and OX-PHOS. mTH completely abrogated the IR increase of plasmatic IL-6 and IL-10 at 24 h. Acute tissue inflammation was decreased by mTH (IL-6 and IL1-β) in as little as 2 h. Concomitantly, mTH increased TNF-α expression at 24 h. One month after IR, mTH increased TNF-α mRNA expression, and it decreased TGF-β mRNA expression. We showed that mTH alleviates renal dysfunction and damage through a preservation of mitochondrial function and a modulated systemic and local inflammatory response at the acute phase (2-24 h). The protective effect of mTH is maintained in the long term (1 month), as it diminished renal atrophy and fibrosis, and mitigated chronic renal inflammation.

Tanshinone IIA Combined With Cyclosporine A Alleviates Lung Apoptosis Induced by Renal Ischemia-Reperfusion in Obese Rats

Acute lung injury (ALI), which is induced by renal ischemia-reperfusion (IR), is one of the leading causes of acute renal IR-related death. Obesity raises the frequency and severity of acute kidney injury (AKI) and ALI. Tanshinone IIA (TIIA) combined with cyclosporine A (CsA) was employed to lessen the lung apoptosis led by renal IR and to evaluate whether TIIA combined with CsA could alleviate lung apoptosis by regulating mitochondrial function through the PI3K/Akt/Bad pathway in obese rats. Hematoxylin-eosin (HE) staining was used to assess the histology of the lung injury. Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) was used to assess apoptosis of the lung. Electron microscopy was used to assess mitochondrial morphology in lung cells. Arterial blood gas and pulmonary function were used to assess the external respiratory function. Mitochondrial function was used to assess the internal respiratory function and mitochondrial dynamics and biogenesis. Western blot (WB) was used to examine the PI3K/Akt/Bad pathway-related proteins. TIIA combined with CsA can alleviate lung apoptosis by regulating mitochondrial function through the PI3K/Akt/Bad pathway in obese rats.

Tanshinone IIA combined with CsA inhibit myocardial cell apoptosis induced by renal ischemia-reperfusion injury in obese rats

BACKGROUND

Acute myocardial injury (AMI), which is induced by renal ischemia-reperfusion (IR), is a significant cause of acute kidney injury (AKI)-related associated death. Obesity increases the severity and frequency of AMI and AKI. Tanshinone IIA (TIIA) combined with cyclosporine A (CsA) pretreatment was used to alleviate myocardial cell apoptosis induced by renal IR, and to determine whether TIIA combined with CsA would attenuate myocardial cell apoptosis by modulating mitochondrial function through the PI3K/Akt/Bad pathway in obese rats.

METHODS

Male rates were fed a high fat diet for 8 weeks to generate obesity. AKI was induced by 30 min of kidney ischemia followed 24 h of reperfusion. Obese rats were given TIIA (10 mg/kg·d) for 2 weeks and CsA (5 mg/kg) 30 min before renal IR. After 24 h of reperfusion, the rats were anaesthetized, the blood were fetched from the abdominal aorta and kidney were fetched from abdominal cavity, then related indicators were examined.

RESULTS

TIIA combined with CsA can alleviate the pathohistological injury and apoptosis induced by renal IR in myocardial cells. TIIA combined with CsA improved cardiac function after renal ischemia (30 min)-reperfusion (24 h) in obese rats. At the same time, TIIA combined with CsA improved mitochondrial function. Abnormal function of mitochondria was supported by decreases in respiration controlling rate (RCR), intracellular adenosine triphosphate (ATP), oxygen consumption rate, and mitochondrial membrane potential (MMP), and increases in mitochondrial reactive oxygen species (ROS), opening of the mitochondrial permeability transition pore (mPTP), mitochondrial DNA damage, and mitochondrial respiratory chain complex enzymes. The injury of mitochondrial dynamic function was assessed by decrease in dynamin-related protein 1 (Drp1), and increases in mitofusin1/2 (Mfn1/2), and mitochondrial biogenesis injury was assessed by decreases in PPARγ coactivator-1-α (PGC-1), nucleo respiratory factor1 (Nrf1), and transcription factor A of mitochondrial (TFam).

CONCLUSION

We used isolated mitochondria from rat myocardial tissues to demonstrate that myocardial mitochondrial dysfunction occurred along with renal IR to induce myocardial cell apoptosis; obesity aggravated apoptosis. TIIA combined with CsA attenuated myocardial cell apoptosis by modulating mitochondrial function through the PI3K/Akt/Bad pathway in obese rats.

An innovative sequence of hypoxia-reoxygenation on adult mouse cardiomyocytes in suspension to perform multilabeling analysis by flow cytometry

Cardiovascular diseases remain the leading cause of death worldwide. Although major therapeutic progress has been made during the past decades, a better understanding of the underlying mechanisms will certainly help to improve patient's prognosis. In vitro models, particularly adult mouse cardiomyocytes, have been largely used; however, their fragility and large size are major obstacles to the use of flow cytometry. Conventional techniques, such as cell imaging, require the use of large numbers of animals and are time consuming. Here, we described a new, simple, and rapid one-day protocol using living adult mouse cardiomyocytes in suspension exposed to hypoxia-reoxygenation that allows a multilabeling analysis by flow cytometry. Several parameters can be measured by fluorescent probes labeling to assess cell viability (propidium iodide, calcein-AM, and Sytox Green), mitochondrial membrane potential [DilC1(5) and TMRM], reactive oxygen species production (MitoSOX Red), and mitochondrial mass (MitoTracker Deep Red). We address the robustness and sensitivity of our model using a cardioprotective agent, cyclosporine A. Overall, our new experimental set-up offers a high-speed quantitative multilabeling analysis of adult mouse cardiomyocytes exposed to hypoxia-reoxygenation. Our model might be interesting to investigate other cellular stresses (oxidative and inflammation) or to perform pharmacological screening.

Protective effect of cyclosporine A in the treatment of severe hydronephrosis in a rabbit renal pelvic perfusion model

Background/aim

Cyclosporine A (CsA), a traditional immunosuppressive compound, has been reported to specifically prevent ischemia reperfusion tissue injury via apoptosis pathway. This study aimed to explore the renoprotective effects of CsA on the kidneys of rabbits undergoing renal pelvic perfusion.

Materials and methods

A total of 30 rabbits were randomly assigned into a control group (n = 6) and an experimental group (n = 24). The experimental group underwent a surgical procedure that induced severe hydronephrosis and was then stochastically divided into 4 groups (S1, S1’, S2, and S2’), consisting of 6 rabbits each. Groups S1 and S1’ were perfused with 20 mmHg of fluid, while groups S2 and S2’ were perfused with 60 mmHg of fluid. Administration to groups S1’ and S2’ was done intravenously, with CsA once a day for 1 week before perfusion. In the control group, after severe hydronephrosis was induced, a sham operation was performed in a second laparotomy. Acute kidney damage was evaluated using hematoxylin and eosin staining, in addition to analyzing the mitochondrial ultrastructure and mitochondrial membrane potential (MMP). The cytochrome C (CytC) and neutrophil gelatinase-associated lipocalin (NGAL) expression were examined immunohistochemically using Western blotting and reverse transcription-polymerase chain reaction.

Results

It was found that the renal histopathological damage was ameliorated, mitochondrial vacuolization was lower, MMP was higher, and the CytC and NGAL contents were decreased after drug intervention (groups S1’ and S2’) when compared to the experimental groups (S1 and S2). Furthermore, there was no difference between drug intervention groups S1’ and S2’.

Conclusion

These results suggest that CsA can attenuate renal damage from severe hydronephrosis induced by renal pelvic perfusion in rabbits. It plays a protective role in the acute kidney injury process, possibly through increased MMP and mitochondrial changes.

Effects of cyclosporine on ischemia-reperfusion injuries in rat kidneys. An experimental model

Purpose

To assess Cyclosporine A (CsA) therapy at an intraperitoneal dose of 15 mg.kg ^-1 in a rodent model of non-septic renal ischemia.

Methods

Twenty male Wistar rats were randomized to receive CsA therapy or none therapy before undergoing 30 minutes of renal ischemia followed by reperfusion. Additionally, 10 rats were randomized to undergo the same surgical procedure of the aforementioned animals with neither ischemia nor CsA therapy. Twelve hours after kidney ischemia, the left kidneys were evaluated for histological injury according to Park’s criteria. Serum creatinine (Cr), urea nitrogen (Ur) and sodium levels were obtained at different times of the experimental protocol.

Results

Rodents in the CsA group showed negative results (p<0.05) in serum variables (Cr: 0.41±0.05mg/dL vs . 4.17±1.25mg/dL; Ur: 40.90±3.98mg/dL vs . 187.70±22.93mg/dL) even the non CsA or control group (Cr: 0.35±0.07mg/dL vs . 3.80±1.20mg/dL; Ur: 40.10±4.70mg/dL vs . 184.50±49.80mg/dL). The negative results were also verified in histological evaluation, CsA group had 50% in the very severe grade of lesion, 10% in the severe and 40% in the moderate to severe whereas the control group had 90% in the very severe grade.

Conclusion

CsA was incapable of preventing the deleterious effects of ischemia-reperfusion injury in rat kidneys.

Emerging therapeutic strategies for transplantation-induced acute kidney injury: protecting the organelles and the vascular bed

INTRODUCTION

Renal ischemia-reperfusion injury (IRI) is a significant clinical challenge faced by clinicians in a broad variety of clinical settings such as perioperative and intensive care. Renal IRI induced acute kidney injury (AKI) is a global public health concern associated with high morbidity, mortality, and health-care costs. Areas covered: This paper focuses on the pathophysiology of transplantation-related AKI and recent findings on cellular stress responses at the intersection of 1. The Unfolded protein response; 2. Mitochondrial dysfunction; 3. The benefits of mineralocorticoid receptor antagonists. Lastly, perspectives are offered to the readers. Expert opinion: Renal IRI is caused by a sudden and temporary impairment of blood flow to the organ. Defining the underlying cellular cascades involved in IRI will assist us in the identification of novel interventional targets to attenuate IRI with the potential to improve transplantation outcomes. Targeting mitochondrial function and cellular bioenergetics upstream of cellular damage may offer several advantages compared to targeting downstream inflammatory and fibrosis processes. An improved understanding of the cellular pathophysiological mechanisms leading to kidney injury will hopefully offer improved targeted therapies to prevent and treat the injury in the future.

Transcriptional trajectories of human kidney injury progression

BACKGROUND

The molecular understanding of the progression from acute to chronic organ injury is limited. Ischemia/reperfusion injury (IRI) triggered during kidney transplantation can contribute to progressive allograft dysfunction.

METHODS

Protocol biopsies (n = 163) were obtained from 42 kidney allografts at 4 time points after transplantation. RNA sequencing-mediated (RNA-seq-mediated) transcriptional profiling and machine learning computational approaches were employed to analyze the molecular responses to IRI and to identify shared and divergent transcriptional trajectories associated with distinct clinical outcomes. The data were compared with the response to IRI in a mouse model of the acute to chronic kidney injury transition.

RESULTS

In the first hours after reperfusion, all patients exhibited a similar transcriptional program under the control of immediate-early response genes. In the following months, we identified 2 main transcriptional trajectories leading to kidney recovery or to sustained injury with associated fibrosis and renal dysfunction. The molecular map generated by this computational approach highlighted early markers of kidney disease progression and delineated transcriptional programs associated with the transition to chronic injury. The characterization of a similar process in a mouse IRI model extended the relevance of our findings beyond transplantation.

CONCLUSIONS

The integration of multiple transcriptomes from serial biopsies with advanced computational algorithms overcame the analytical hurdles related to variability between individuals and identified shared transcriptional elements of kidney disease progression in humans, which may prove as useful predictors of disease progression following kidney transplantation and kidney injury. This generally applicable approach opens the way for an unbiased analysis of human disease progression.

FUNDING

The study was supported by the California Institute for Regenerative Medicine and by the Swiss National Science Foundation.