Chronic lithium treatment protects the rat kidney against ischemia/reperfusion injury: the role of nitric oxide and cyclooxygenase pathways

The Dual-specificity Phosphatase 3 (DUSP3): A Potential Target Against Renal Ischemia/Reperfusion Injury

Renal ischemia/reperfusion (I/R) injury is a common clinical challenge faced by clinicians in kidney transplantation. I/R is the leading cause of acute kidney injury, and it occurs when blood flow to the kidney is interrupted and subsequently restored. I/R impairs renal function in both short and long terms. Renal ischemic preconditioning refers to all maneuvers intended to prevent or attenuate ischemic damage. In this context, the present review focuses on the dual-specificity phosphatase 3 (DUSP3), also known as vaccinia H1-related phosphatase, an uncommon regulator of mitogen-activated protein kinase (MAPK) phosphorylation. DUSP3 has different biological functions: (1) it acts as a tumor modulator and (2) it is involved in the regulation of immune response, thrombosis, hemostasis, angiogenesis, and genomic stability. These functions occur either through MAPK-dependent or MAPK-independent mechanisms. DUSP3 genetic deletion dampens kidney damage and inflammation caused by I/R in mice, suggesting DUSP3 as a potential target for preventing renal I/R injury. Here, we discuss the putative role of DUSP3 in ischemic preconditioning and the potential mechanisms of such an attenuated inflammatory response via improved kidney perfusion and adequate innate immune response.

Tubuloid differentiation to model the human distal nephron and collecting duct in health and disease

Organoid technology is rapidly gaining ground for studies on organ (patho)physiology. Tubuloids are long-term expanding organoids grown from adult kidney tissue or urine. The progenitor state of expanding tubuloids comes at the expense of differentiation. Here, we differentiate tubuloids to model the distal nephron and collecting ducts, essential functional parts of the kidney. Differentiation suppresses progenitor traits and upregulates genes required for function. A single-cell atlas reveals that differentiation predominantly generates thick ascending limb and principal cells. Differentiated human tubuloids express luminal NKCC2 and ENaC capable of diuretic-inhibitable electrolyte uptake and enable disease modeling as demonstrated by a lithium-induced tubulopathy model. Lithium causes hallmark AQP2 loss, induces proliferation, and upregulates inflammatory mediators, as seen in vivo. Lithium also suppresses electrolyte transport in multiple segments. In conclusion, this tubuloid model enables modeling of the human distal nephron and collecting duct in health and disease and provides opportunities to develop improved therapies.

Nitric Oxide in Cardiac Surgery: A Review Article

Perioperative organ injury remains a medical, social and economic problem in cardiac surgery. Patients with postoperative organ dysfunction have increases in morbidity, length of stay, long-term mortality, treatment costs and rehabilitation time. Currently, there are no pharmaceutical technologies or non-pharmacological interventions that can mitigate the continuum of multiple organ dysfunction and improve the outcomes of cardiac surgery. It is essential to identify agents that trigger or mediate an organ-protective phenotype during cardiac surgery. The authors highlight nitric oxide (NO) ability to act as an agent for perioperative protection of organs and tissues, especially in the heart-kidney axis. NO has been delivered in clinical practice at an acceptable cost, and the side effects of its use are known, predictable, reversible and relatively rare. This review presents basic data, physiological research and literature on the clinical application of NO in cardiac surgery. Results support the use of NO as a safe and promising approach in perioperative patient management. Further clinical research is required to define the role of NO as an adjunct therapy that can improve outcomes in cardiac surgery. Clinicians also have to identify cohorts of responders for perioperative NO therapy and the optimal modes for this technology.

Beyond its Psychiatric Use: The Benefits of Low-dose Lithium Supplementation

Lithium is most well-known for its mood-stabilizing effects in the treatment of bipolar disorder. Due to its narrow therapeutic window (0.5-1.2 mM serum concentration), there is a stigma associated with lithium treatment and the adverse effects that can occur at therapeutic doses. However, several studies have indicated that doses of lithium under the predetermined therapeutic dose used in bipolar disorder treatment may have beneficial effects not only in the brain but across the body. Currently, literature shows that low-dose lithium (≤0.5 mM) may be beneficial for cardiovascular, musculoskeletal, metabolic, and cognitive function, as well as inflammatory and antioxidant processes of the aging body. There is also some evidence of low-dose lithium exerting a similar and sometimes synergistic effect on these systems. This review summarizes these findings with a focus on low-dose lithium's potential benefits on the aging process and age-related diseases of these systems, such as cardiovascular disease, osteoporosis, sarcopenia, obesity and type 2 diabetes, Alzheimer's disease, and the chronic low-grade inflammatory state known as inflammaging. Although lithium's actions have been widely studied in the brain, the study of the potential benefits of lithium, particularly at a low dose, is still relatively novel. Therefore, this review aims to provide possible mechanistic insights for future research in this field.

Suppressive effect erythropoietin on oxidative stress by targeting AMPK/Nox4/ROS pathway in renal ischemia reperfusion injury

OBJECTIVE

To explore the effect of erythropoietin (EPO) on the AMP-activated protein kinase (AMPK)/nicotinamide adenine dinucleotide phosphatase oxidase 4 (NOX4) signaling pathway during renal ischemia reperfusion injury (RIRI) in rats.

METHODS

A rat model of RIRI was established by clamping the left renal pedicle and removing the right kidney. The rats in the sham group did not have their left renal pedicle clamped. Rats with a model of RIRI were randomly divided into RIRI alone (control), erythropoietin treatment (EPO/RIRI), and Compound C treatment (CPC/RIRI) groups. Hematoxylin-eosin (H&E) staining was used to examine pathological kidney damage. Serum creatinine and urea nitrogen levels were measured to evaluate renal function. Western blotting was performed to detect the expression levels of phosphorylated p-AMPK and total AMPK protein in the kidneys. RT-PCR was used to evaluate the mRNA levels of Nox4 and p22 in the kidneys. Oxidative stress-related indices (ROS, CAT, GSH, SOD, and MDA) were also measured.

RESULTS

EPO treatment improved kidney function by preventing kidney damage induced by the RIRI model. Preventing ischemia/reperfusion injury in the RIRI model was correlated with an increased p-AMPK/AMPK ratio and elevated activity of CAT, GSH, and SOD, which ameliorated the expression of NOX4, p22, ROS, and MDA. Moreover, treatment with CPC (an AMPK inhibitor) reduced the effects of EPO in the RIRI model.

CONCLUSION

EPO treatment protected rats against RIRI in the RIRI model by alleviating oxidative stress by triggering the AMPK/NOX4/ROS pathway.

[Lithium in the psychopharmacology of affective disorders and mechanisms of its effects on cellular physiology]

However, despite successful use of lithium in the treatment of affective disorders for almost 40 years, the mechanisms of its therapeutic action are still poorly understood. This review presents and summarizes the current literature about the use of lithium in treatment of affective disorders, as well as its effects on cellular physiology, with a separate description of the effect of this ion on the functioning of nerve tissue and ion-molecular mechanisms.

Chloroquine attenuates lithium-induced NDI and proliferation of renal collecting duct cells

Lithium is widely used in psychiatry as the golden standard for more than 60 yr due to its effectiveness. However, its adverse effect has been limiting its long-term use in clinic. About 40% of patients taking lithium develop nephrogenic diabetes insipidus (NDI). Lithium can also induce proliferation of collecting duct cells, leading to microcyst formation in the kidney. Lithium was considered an autophagy inducer that might contribute to the therapeutic benefit of neuropsychiatric disorders. Thus, we hypothesized that autophagy may play a role in lithium-induced kidney nephrotoxicity. To address our hypothesis, we fed mice with a lithium-containing diet with chloroquine (CQ), an autophagy inhibitor, concurrently. Lithium-treated mice presented enhanced autophagy activity in the kidney cortex and medulla. CQ treatment significantly ameliorated lithium-induced polyuria, polydipsia, natriuresis, and kaliuresis accompanied with attenuated downregulation of aquaporin-2 and Na⁺-K⁺-2Cl^- cotransporter protein. The protective effect of CQ on aquaporin-2 protein abundance was confirmed in cultured cortical collecting duct cells. In addition, we found that lithium-induced proliferation of collecting duct cells was also suppressed by CQ as detected by proliferating cell nuclear antigen staining. Moreover, both phosphorylated mammalian target of rapamycin and β-catenin expression, which have been reported to be increased by lithium and associated with cell proliferation, were reduced by CQ. Taken together, our study demonstrated that CQ protected against lithium-induced NDI and collecting duct cell proliferation possibly through inhibiting autophagy.

Autophagy Function and Regulation in Kidney Disease

Autophagy is a dynamic process by which intracellular damaged macromolecules and organelles are degraded and recycled for the synthesis of new cellular components. Basal autophagy in the kidney acts as a quality control system and is vital for cellular metabolic and organelle homeostasis. Under pathological conditions, autophagy facilitates cellular adaptation; however, activation of autophagy in response to renal injury may be insufficient to provide protection, especially under dysregulated conditions. Kidney-specific deletion of Atg genes in mice has consistently demonstrated worsened acute kidney injury (AKI) outcomes supporting the notion of a pro-survival role of autophagy. Recent studies have also begun to unfold the role of autophagy in progressive renal disease and subsequent fibrosis. Autophagy also influences tubular cell death in renal injury. In this review, we reported the current understanding of autophagy regulation and its role in the pathogenesis of renal injury. In particular, the classic mammalian target of rapamycin (mTOR)-dependent signaling pathway and other mTOR-independent alternative signaling pathways of autophagy regulation were described. Finally, we summarized the impact of autophagy activation on different forms of cell death, including apoptosis and regulated necrosis, associated with the pathophysiology of renal injury. Understanding the regulatory mechanisms of autophagy would identify important targets for therapeutic approaches.

The Impact Of Succinate Dehydrogenase Gene (SDH) Mutations In Renal Cell Carcinoma (RCC): A Systematic Review

INTRODUCTION

Renal cell cancer (RCC) syndrome is linked to Krebs cycle compartments and their coding genes' alterations like succinate dehydrogenase genes (SDHx). Here we present a systematic review of the SDH genes' mutations and their impact on both RCC diagnosis and prognosis.

METHODS

This systematic review includes any study in which tissue samples of RCC are considered in correlation with the SDHx mutations, microsatellite instability (MSI), and protein expression. For this purpose, a systematic search of MEDLINE (PubMed), Scopus, Embase, and Web of Science databases was conducted and finally 5384 articles were recruited. All studies' content was checked to find the related ones which were 145 articles, which with data extraction were limited to nineteen.

RESULTS

The final selected nineteen studies investigating the SDHx role in RCC tumor genesis were included, among which fifteen were mutation analysis, three were just SDHx protein expression, and two were MSI and mutation analysis studies. A total of 432 RCC patients were reported by SDH mutations, and 64 patients with MSI and SDH expression change were reported in 514 surgically resected renal epithelial tumors. The most common mutation was the single nucleotide variant rs772551056 (c.137G>A) of SDHB. For SDHC, c.380A>G presented in 48 RCC patients, and for SDHA a novel germline mutation c.2T>C: p.M1T in an occasional case of gastrointestinal stromal tumor intricate with RCC.

CONCLUSION

RCC as an aggressive type of kidney cancer needs some biomarkers to be diagnosed exactly. It was shown recently that the succinate dehydrogenase gene variations can provide this diagnostic and prognostic biomarker. For this purpose, SDHB rs772551056 associated with its protein expression alterations can be taken into account. It is possible that a novel mutation of SDHA (c.2T>C: p.M1T) can provide evidence of GIST associated with RCC as well.

Induction of autophagy reduces ischemia/reperfusion injury in steatotic rat livers

BACKGROUND

Steatotic livers are particularly vulnerable to ischemia/reperfusion injury (IRI). One of the reasons is an underlying impairment of autophagy. Autophagy is regulated by glycogen synthase kinase 3b (GSK3b) and extracellular signal-regulated kinases (ERK1/2) pathways. Both of them are target proteins of a cell-protective drug, lithium chloride. Lithium chloride treatment reduces IRI in many organs including liver. Therefore, we aimed to investigate the effect of lithium chloride treatment on autophagy induction in steatotic rat livers. We also wanted to evaluate the related cell-protective effects on the enhanced hepatic IRI.

MATERIALS AND METHODS

After inducing hepatic steatosis, rats were injected with lithium chloride or normal saline for 3 d before being subjected to 70% selective warm ischemia for 60 min. After reperfusion, rats were observed for 30 min, 6, 24, and 48 h.

RESULTS

Lithium chloride appeared to protect hepatocytes from IRI via its ability to induce autophagy by modulation of both GSK3b and ERK1/2 pathways. Hepatic damage was significantly decreased in the treatment group as indicated by a reduced inflammatory response, less apoptosis, less necrosis, and lower liver enzyme levels.

CONCLUSIONS

Simultaneous modulation of GSK3b and ERK1/2 pathways might be an interesting strategy to reduce IRI in steatotic livers with an impairment of autophagy.

Lithium in the Kidney: Friend and Foe?

Trace amounts of lithium are essential for our physical and mental health, and administration of lithium has improved the quality of life of millions of patients with bipolar disorder for >60 years. However, in a substantial number of patients with bipolar disorder, long-term lithium therapy comes at the cost of severe renal side effects, including nephrogenic diabetes insipidus and rarely, ESRD. Although the mechanisms underlying the lithium-induced renal pathologies are becoming clearer, several recent animal studies revealed that short-term administration of lower amounts of lithium prevents different forms of experimental AKI. In this review, we discuss the knowledge of the pathologic and therapeutic effects of lithium in the kidney. Furthermore, we discuss the underlying mechanisms of these seemingly paradoxical effects of lithium, in which fine-tuned regulation of glycogen synthase kinase type 3, a prime target for lithium, seems to be key. The new discoveries regarding the protective effect of lithium against AKI in rodents call for follow-up studies in humans and suggest that long-term therapy with low lithium concentrations could be beneficial in CKD.

Dual effect of lithium on NFAT5 activity in kidney cells

Lithium salts are used widely for treatment of bipolar and other mental disorders. Lithium therapy is accompanied frequently by renal side effects, such as nephrogenic diabetes insipidus or chronic kidney disease (CKD), but the molecular mechanisms underlying these effects are still poorly understood. In the present study we examined the effect of lithium on the activity of the osmosensitive transcriptional activator nuclear factor of activated T cells 5 (NFAT5, also known as TonEBP), which plays a key role in renal cellular osmoprotection and urinary concentrating ability. Interestingly, we found different effects of lithium on NFAT5 activity, depending on medium osmolality and incubation time. When cells were exposed to lithium for a relative short period (24 h), NFAT5 activity was significantly increased, especially under isosmotic conditions, resulting in an enhanced expression of the NFAT5 target gene heat shock protein 70 (HSP70). Further analysis revealed that the increase of NFAT5 activity depended primarily on an enhanced activity of the c-terminal transactivation domain (TAD), while NFAT5 protein abundance was largely unaffected. Enhanced activity of the TAD is probably mediated by lithium-induced inhibitory phosphorylation of glycogen synthase kinase 3β (GSK-3β), which is in accordance with previous studies. When cells were exposed to lithium for a longer period (96 h), cellular NFAT5 activity and subsequently expression of HSP70 significantly decreased under hyperosmotic conditions, due to diminished NFAT5 protein abundance, also resulting from GSK-3β inhibition. Taken together, our results provide evidence that lithium has opposing effects on NFAT5 activity, depending on environmental osmolality and exposure duration. The potential impacts of these observations on the diverse effects of lithium on kidney function are discussed.

Protective effect of indomethacin in renal ischemia-reperfusion injury in mice

OBJECTIVE

To evaluate the renoprotection effects of non-steroidal anti-inflammatory drugs (NSAIDs) in renal ischemia-reperfusion injury (IRI) and the cyclooxygenase (COX)-1/2 blockade association by indomethacin (IMT) in the mice model.

METHODS

After the left renal pedicle of mice was clamped, IMT was administrated by intraperitoneal injection with four doses: 1, 3, 5, and 7 mg/kg. Blood and kidney samples were collected 24 h after IRI. The renal functions were assayed by the cytokines and serum creatinine (SCr) using enzyme-linked immunosorbent assay (ELISA) kits. Kidney samples were analyzed by hematoxylin and eosin (H&E) and immunohistochemistry stainings.

RESULTS

The mice administered with 5 mg/kg IMT had a marked reduction in SCr and significantly less tubular damage. The tumor necrosis factor α (TNF-α) activity in renal homogenates and interleukin 6 (IL-6) activity in serum had a marked reduction at doses of 5 and 7 mg/kg IMT. The administration of 3 and 5 mg/kg IMT had a marked reduction in the ratio of thromboxane B2 to 6-keto-prostaglandin F1α. COX-1 and COX-2 stainings were weaker in 5 mg/kg IMT groups than that in the other groups.

CONCLUSIONS

There was a dose response in the IMT function of renal IRI in mice, and IMT had a protective effect in a certain dose range. The effect of IMT on mice IRI was related to COX-1/2 blockades.

Chronic lithium treatment protects against liver ischemia/reperfusion injury in rats

Lithium has long been widely used in the treatment of bipolar mood disorders. Recent studies have demonstrated that lithium is able to decrease ischemia/reperfusion (I/R) injury in the brain, kidneys, and heart. Because lithium may act on a number of stress and survival pathways, it is of great interest to explore this compound also in the setting of liver I/R injury. In this study, we aimed to evaluate the effects of lithium in a model of liver I/R injury in rats. Chronic treatment with lithium (2 mmol/kg for 3 days before ischemia) decreased I/R injury, whereas acute treatment with a single dose of lithium (2 mmol/kg 1 hour before ischemia) did not confer any protection in a partial hepatic I/R model. Furthermore, rats subjected to chronic lithium treatment had a significantly better survival rate (60%) than saline-treated rats (27%) in a total hepatic I/R survival model. Chronic lithium treatment protected against liver I/R injury, as indicated by lower serum aminotransferase levels, fewer I/R-associated histopathological changes, lower hepatic inflammatory cytokine levels, less neutrophil infiltration, and lower hepatic high-mobility group box expression and serum levels. The mechanism of action of lithium appears to involve its ability to inhibit glycogen synthase kinase 3β activation, modulate mitogen-activated protein kinase activation, inhibit hepatic apoptosis, and induce autophagy. On the basis of these data, we conclude that lithium treatment may be a simple and applicable preconditioning intervention for protecting against liver I/R injury.

Lithium exacerbates hepatic ischemia/reperfusion injury by inhibiting GSK-3β/NF-κB-mediated protective signaling in mice

Lithium (an inhibitor of GSK-3β activity) has beneficial effects on ischemia/reperfusion (I/R) injury in the central nervous system, heart and kidney. However, the role of lithium in hepatic I/R injury is unknown. The aim of this study was to assess the effects of lithium on hepatic I/R injury in a mouse model of partial hepatic I/R. Previous studies showed that lithium chloride (LiCl) can phosphorylate residue Ser9, inhibit GSK-3β activity, and improve I/R injury in other organs. In the present study, mice were pretreated with either vehicle or LiCl, which had similar effects on GSK-3β activity. Surprisingly, treatment with LiCl significantly exacerbated hepatic I/R injury, which was determined by serological and histological analyses. Acute and chronic LiCl treatment caused serious damage in hepatic I/R injury, including increased apoptosis and oxidative stress. To gain insight into the mechanism involved in this damage, the activity of nuclear factor-κB (NF-κB) (GSK-3β can regulate the transcriptional complex of NF-κB) was analyzed, which revealed that LiCl treatment significantly down-regulated the activity of NF-κB. The NF-κB-mediated protective genes were then further evaluated, including anti-apoptotic genes (RAF2, cIAP 2, Bfl-1 and cFLIP) and the antioxidant gene MnSOD. The expression of these protective genes was obviously suppressed compared with the vehicle group. Taken together, these findings show that lithium exacerbates hepatic I/R injury by suppressing the expression of GSK-3β/NF-κB-mediated protective genes.

Preservation strategies to reduce ischemic injury in kidney transplantation: pharmacological and genetic approaches

PURPOSE OF REVIEW

In the current graft shortage, it is paramount to improve the quality of transplanted organs. Organ preservation represents an underused therapeutic window with great potential to reduce ischaemia-reperfusion injury (IRI) and improve graft quality. Herein, we review strategies using this window as well as other promising work targeting IRI pathways using pharmacological treatments and gene therapy.

RECENT FINDINGS

We highlight studies using molecules administered during kidney preservation to target key components of IRI such as inflammation, oxidative stress, mitochondrial activity and the coagulation pathway. We further expose recent studies of gene therapy directed against inflammation or apoptosis during cold storage. Other pathways with potential therapeutic molecules are cited.

SUMMARY

The use of cold preservation as a therapeutic window to deliver pharmacological or gene therapy treatments can significantly improve both short-term and long-term graft outcomes. Even if human gene therapy remains hampered by the quantity of agent needed and the potential harmfulness of the vector, it clearly offers a wide array of possibilities for the future. Although gene therapy is still too immature, we expose pharmacological strategies which can readily be applied to the clinic and improve both transplantation success rates and the patients' quality of life.