Enhanced MCP-1 expression during ischemia/reperfusion injury is mediated by oxidative stress and NF-kappaB

Mucuna laticifera: unprecedented L-dopa content and its role in neurodegenerative and inflammatory conditions

Genus Mucuna encompasses several plant species renowned for their utilization in traditional Ayurvedic medicine for the treatment of Parkinson's disease, chiefly due to their exceptionally high L-dopa content relative to other plants. However, limited information exists regarding Mucuna laticifera, a newly identified species within the Mucuna genus. This study unveils a remarkable L-dopa content of 174.3 mg/g in M. laticifera seeds, surpassing all previously documented Mucuna species. Moreover, this research marks the first documentation of L-dopa, flavonoids, and phenolics within M. laticifera seeds. Furthermore, the aqueous extract derived from these seeds exhibits robust antioxidant properties. Investigation into its anti-inflammatory potential reveals a significant reduction in paw swelling and neutrophil infiltration at inflammatory sites in a carrageenan-induced rat model. Gene expression analysis utilizing a rat paw model demonstrates that the seed extract significantly downregulates the expression of various inflammation-related genes compared to carrageenan-treated rats. Collectively, these findings clearly substantiate the anti-inflammatory activity of M. laticifera seed extract. The exceptional L-dopa content combined with its anti-inflammatory properties position M. laticifera seeds as a promising therapeutic option for neurodegenerative diseases like Parkinson's, as well as various inflammatory conditions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-03969-w.

Critical Role of histone deacetylase 3 in the regulation of kidney inflammation and fibrosis

Chronic kidney disease (CKD) is characterized by kidney inflammation and fibrosis. However, the precise mechanisms leading to kidney inflammation and fibrosis are poorly understood. Since histone deacetylase is involved in inflammation and fibrosis in other tissues, we examined the role of histone deacetylase 3 (HDAC3) in the regulation of inflammation and kidney fibrosis. HDAC3 is induced in the kidneys of animal models of CKD but mice with conditional HDAC3 deletion exhibit significantly reduced fibrosis in the kidneys compared with control mice. The expression of proinflammatory and profibrotic genes was significantly increased in the fibrotic kidneys of control mice, which was impaired in mice with HDAC3 deletion. Genetic deletion or pharmacological inhibition of HDAC3 reduced the expression of proinflammatory genes in cultured monocytes/macrophages. Mechanistically, HDAC3 deacetylates Lys122 of NF-κB p65 subunit turning on transcription. RGFP966, a selective HDAC3 inhibitor, reduced fibrosis in cells and in animal models by blocking NF-κB p65 binding to κB-containing DNA sequences. Thus, our study identified HDAC3 as a critical regulator of inflammation and fibrosis of the kidney through deacetylation of NF-κB unlocking its transcriptional activity. Hence, targeting HDAC3 could serve as a novel therapeutic strategy for CKD.

Exploration of the shared gene signatures and biological mechanisms between ischemia-reperfusion injury and antibody-mediated rejection in renal transplantation

BACKGROUND

Antibody-mediated rejection (ABMR) plays a crucial role in graft loss during allogeneic renal transplantation. In renal transplantation, ischemia-reperfusion injury (IRI) is unavoidable, serves as a major contributor to acute rejection, and is linked to graft loss. However, the mechanisms underlying IRI and ABMR are unclear. Therefore, this study aimed to investigate the shared genetic characteristics and biological mechanisms between IRI and ABMR.

METHODS

Gene expressions for IRI (GSE43974) and ABMR (GSE129166 and GSE36059) were retrieved from the Gene Expression Omnibus database. The shared differentially expressed genes (DEGs) of IRI and ABMR were identified, and subsequent functional enrichment analysis was performed. Immune cell infiltration in ABMR and its relationship with the shared DEGs were investigated using the CIBERSORT method. Random forest analysis, a protein-protein interaction network, and Cytoscape were used to screen hub genes, which were subsequently subjected to gene set enrichment analysis, miRNA prediction, and transcription factors analysis. The survival analysis was performed through Kaplan-Meier curves. Finally, drug compound prediction was performed on the shared DEGs using the Drug Signature Database.

RESULTS

Overall, 27 shared DEGs were identified between the renal IRI and ABMR groups. Among these, 24 genes exhibited increased co-expression, whereas none showed decreased co-expression. The shared DEGs were primarily enriched in the inflammation signaling pathways. Notably, CD4 memory T cells were identified as potential critical mediators of IRI, leading to ABMR. Tumor necrosis factor alpha-induced protein 3 (TNFAIP3), interferon regulatory factor 1 (IRF1), and early growth response 2 (EGR2) were identified as key components in the potential mechanism that link IRI and ABMR. Patients undergoing renal transplantation with higher expression levels of TNFAIP3, IRF1, and EGR2 exhibited decreased survival rates compared to those with lower expression levels.

CONCLUSION

Inflammation is a key mechanism that links IRI and ABMR, with a potential role played by CD4 memory T cells. Furthermore, TNFAIP3, IRF1, and EGR2 are implicated in the underlying mechanism between IRI and ABMR.

Obesity Blunts the Effect of Mesenchymal Stem Cell-Derived Extracellular Vesicles

Introduction

Mesenchymal stem/stromal cell-derived extracellular vesicles (MSC-EVs) are paracrine vectors with therapeutic functions comparable to their parent cells. However, it remains unclear if donor obesity affects their therapeutic functions. We tested the hypothesis that the curative effect of human adipose tissue-derived MSC-EVs (A-MSC-EVs) is blunted by obesity.

Methods

MSC-EVs were isolated by ultracentrifugation from mesenchymal stem/stromal cells (MSCs) collected from abdominal subcutaneous fat of obese and lean human subjects (obese and lean-MSC-EVs, respectively) and injected into the aorta of mice 2 weeks after renal artery stenosis (RAS) induction. Magnetic resonance imaging studies were conducted 2 weeks after MSC-EVs delivery to determine renal function. The effect of MSC-EVs on tissue injury was assessed by histology and gene expression of inflammatory factors, including interleukin (IL)-1β, IL-6, monocyte chemotactic protein-1 (MCP-1), and tumor necrosis factor alpha (TNF-α). Oxidative damage, macrophage infiltration, plasma renin, and hypoxia inducible factor-1α (HIF-1α) were also assessed.

Results

Tracking showed that MSC-EVs localized in the kidney tissue, including glomeruli and tubules. All MSC-EVs decreased systolic blood pressure (SBP) and plasma renin and improved the poststenotic kidney (STK) volume, but obese-MSC-EVs were less effective than lean-MSC-EVs in improving medullary hypoxia, fibrosis, and tubular injury. Lean-MSC-EVs decreased inflammation, whereas obesity attenuated this effect. Only lean-MSC-EVs decreased STK cortical HIF-1α expression.

Conclusion

Obesity attenuates the antihypoxia, antifibrosis, antiinflammation, and tubular repair functions of human MSC-EVs in chronic ischemic kidney disease. These observations may have implications for the self-repair potency of obese subjects and for the use of autologous MSC-EVs in regenerative medicine.

Potential utility of urinary chemokine CCL2 to creatinine ratio in prognosis of 5-year graft failure and mortality post 1-year protocol biopsy in kidney transplant recipients

BACKGROUND

Chemokines (chemotactic cytokines) are small proteins which are engaged in many pathophysiological processes, including inflammation and homeostasis. In recent years, application of chemokines in transplant medicine was intensively studied. The aim of this study was to determine the utility of urinary chemokines CCL2 (C-C motif ligand 2) and CXCL10 (C-X-C motif chemokine ligand 10) in prognosis of 5-year graft failure and mortality post 1-year protocol biopsy in renal transplant recipients.

METHODS

Forty patients who had a protocol biopsy 1 year after renal transplantation were included. Concentrations of CCL2 and CXCL10 in urine with reference to urine creatinine were measured. All patients were under the supervision of one transplant center. Long-term outcomes within 5 years after 1-year posttransplant biopsy were analyzed.

RESULTS

Urinary CCL2:Cr at the time of biopsy was significantly increased in patients who died or had graft failure. CCL2:Cr was proven to be a significant predictor of 5-year graft failure and mortality (odds ratio [OR]: 1.09, 95% confidence interval [CI]: 1.02-1.19, p = .02; OR: 1.08, 95% CI: 1.02-1.16, p = .04; respectively).

CONCLUSION

Chemokines are easily detected by current methods. In the era of personalized medicine, urinary CCL2:Cr can be considered as a factor providing complementary information regarding risk of graft failure or increased mortality.

Sterile Pancreas Inflammation during Preservation and after Transplantation

The pancreas is very susceptible to ischemia-reperfusion injury. Early graft losses due to pancreatitis and thrombosis represent a major issue after pancreas transplantation. Sterile inflammation during organ procurement (during brain death and ischemia-reperfusion) and after transplantation affects organ outcomes. Sterile inflammation of the pancreas linked to ischemia-reperfusion injury involves the activation of innate immune cell subsets such as macrophages and neutrophils, following tissue damage and release of damage-associated molecular patterns and pro-inflammatory cytokines. Macrophages and neutrophils favor tissue invasion by other immune cells, have deleterious effects or functions, and promote tissue fibrosis. However, some innate cell subsets may promote tissue repair. This outburst of sterile inflammation promotes adaptive immunity activation via antigen exposure and activation of antigen-presenting cells. Better controlling sterile inflammation during pancreas preservation and after transplantation is of utmost interest in order to decrease early allograft loss (in particular thrombosis) and increase long-term allograft survival. In this regard, perfusion techniques that are currently being implemented represent a promising tool to decrease global inflammation and modulate the immune response.

Pathological Mechanisms Induced by TRPM2 Ion Channels Activation in Renal Ischemia-Reperfusion Injury

Renal ischemia-reperfusion (IR) injury triggers a cascade of signaling reactions involving an increase in Ca^{2 +} charge and reactive oxygen species (ROS) levels resulting in necrosis, inflammation, apoptosis, and subsequently acute kidney injury (AKI).Transient receptor potential (TRP) channels include an essential class of Ca²⁺ permeable cation channels, which are segregated into six main channels: the canonical channel (TRPC), the vanilloid-related channel (TRPV), the melastatin-related channel (TRPM), the ankyrin-related channel (TRPA), the mucolipin-related channel (TRPML) and polycystin-related channel (TRPP) or polycystic kidney disease protein (PKD2). TRP channels are involved in adjusting vascular tone, vascular permeability, cell volume, proliferation, secretion, angiogenesis and apoptosis.TRPM channels include eight isoforms (TRPM1-TRPM8) and TRPM2 is the second member of this subfamily that has been expressed in various tissues and organs such as the brain, heart, kidney and lung. Renal TRPM2 channels have an important role in renal IR damage. So that TRPM2 deficient mice are resistant to renal IR injury. TRPM2 channels are triggered by several chemicals including hydrogen peroxide, Ca²⁺, and cyclic adenosine diphosphate (ADP) ribose (cADPR) that are generated during AKI caused by IR injury, as well as being implicated in cell death caused by oxidative stress, inflammation, and apoptosis.

Galaxaura elongata Extract (GE) Modulates Vanadyl Sulfate-Induced Renal Damage via Regulating TGF-β/Smads and Nrf2/NF-κB Pathways

Nephrotoxicity becomes a provoked problem as the kidneys are the target of many chemotherapies. For this reason, we aimed to study the protective effect of Galaxaura elongata extract (GE) against the vanadyl sulfate (Van) induced nephrotoxicity in rats. Forty Wistar albino rats (male) were divided into four groups (n = 10) as follows: control group: rats received 0.5% carboxymethyl cellulose (CMC). Galaxa group: rats received GE at a dose (100 mg/kg orally) daily for 6 weeks. Van group: rats injected with Van at a dose (50 mg/kg i.p.) once weekly for 6 successive weeks. Galaxa + Van group: rats received GE at a dose (100 mg/kg orally) daily for 6 weeks concurrently with Van at a dose (50 mg/kg i.p.) for 6 weeks. Our results showed that Van significantly raised urea and creatinine serum levels as compared to the control group as well as disordered renal oxidative/antioxidant redox. Administration of GE with Van alleviated the adverse impact of Van over the kidney tissues. Furthermore, GE administration in Galaxa + Van group downregulates angiotensin-converting enzyme (ACE1) mRNA expression, angiotensin II (Ang II) concentration, transforming growth factor β (TGF-β) mRNA expression and protein concentration and Nuclear factor κB (NF-κB) mRNA expression as compared to Van group. Also, GE administration caused a noticeable upregulation of Nrf2 and heme oxygenase-1 (HO-1) expressions with a consequent decrease of DNA fragmentation % compared to Van group. The results of the current study show that simultaneous treatment with GE can alleviate nephrotoxicity caused by Van in diabetic rats. The GE treatment of the Van treated animals restored altered renal oxidative/antioxidant redox values towards normal and lessened fibrosis. These results are consistent with these effects being caused by interactions with the TGF-B/Smads and Nrf2/NF-κB signaling pathways.

5-Methyltetrahydrofolate Attenuates Oxidative Stress and Improves Kidney Function in Acute Kidney Injury through Activation of Nrf2 and Antioxidant Defense

Oxidative stress is a major mediator of adverse outcomes in acute kidney injury (AKI). Deficiency of micronutrients, such as folate, is common in AKI. Our previous study reported that AKI impaired kidney reabsorption of folate and decreased plasma folate level in rats. The present study investigated the effect of 5-methyltetrahydrofolate (5-MTHF), a biologically active form of folate/folic acid, on AKI-impaired kidney function and oxidative stress. Sprague-Dawley rats developed AKI after kidney ischemia (45 min) and reperfusion (24 h). Injection of 5-MTHF (3 µg/kg body weight) improved kidney function and attenuated oxidative stress with a restoration of glutathione and a reduction of lipid peroxidation in the kidney. Injection of 5-MTHF activated transcription factor Nrf2 and increased the expression of glutathione synthesizing enzymes, superoxide dismutase-1 and heme oxygenase-1 in the kidney. Simulated ischemia-reperfusion through hypoxia-reoxygenation increased oxidative stress in proximal tubular cells. Incubation of cells with 5-MTHF alleviated cell injury and increased antioxidant enzyme expression and intracellular glutathione levels. Inhibition of Nrf2 expression through siRNA transfection abolished the effect of 5-MTHF against oxidative stress. These results suggest that low-dose folic acid can improve kidney function through activation of Nrf2 and restoration of antioxidant defence. Micronutrient supplements may improve clinical outcomes in AKI.

IFC-305 attenuates renal ischemia-reperfusion injury by promoting the production of hydrogen sulfide (H2S) via suppressing the promoter methylation of cystathionine γ-lyase (CSE)

Renal ischemia-reperfusion (I/R) injury is characterized by elevated expression of homocysteine and decreased production of hydrogen sulfide (H₂S). Cystathionine γ-lyase (CSE) is a key factor in the onset of renal I/R injury, while IFC-305 can regulate the expression of CSE via epigenetic modification. Animal and cellular models of I/R were established in this work, followed by H&E staining to evaluate the extent of renal tissue injury under distinct conditions. Several methods, including ELISA, qPCR and Western blot, were used to analyze the levels of creatinine, CSE and H₂S in various I/R models. Bisulfite sequencing PCR was used to evaluate the level of DNA methylation. The severity of the renal injury was significantly elevated in I/R rats and alleviated by the IFC-305 treatment. The level of Hcy was increased in the renal tissue and peripheral blood of I/R rats, while the IFC-305 treatment inhibited the expression of homocysteine (Hcy). Mechanistically, the DNA methylation in the CSE promoter was dramatically enhanced in I/R rats and cells, while the IFC-305 treatment reduced the level of DNA methylation in the CSE promoter. Moreover, the IFC-305 increased the concentration of H₂S, which was reduced in I/R rats and cells. Finally, I/R rats and cells showed aberrantly high levels of MDA and superoxide, while the IFC-305 treatment reduced the levels of malondialdehyde (MDA) and superoxide. IFC-305, an adenosine derivative, promoted the production of H₂S and attenuated renal injury in cellular and animal models of renal I/R by modifying the methylation status of the CSE promoter.

Ischemic Preconditioning Alleviates Mouse Renal Ischemia/Reperfusion Injury by Enhancing Autophagy Activity of Proximal Tubular Cells

OBJECTIVES

Ischemia/reperfusion injury (IRI) is one of the most vital pathogenesis leading to kidney injury but lacks effective prevention and treatment strategies. This study was conducted to investigate the influences of ischemic preconditioning (IPC) on the pathological process of mouse renal IRI (RIRI) and to figure out the role of autophagy of proximal tubular cells (PTCs) in this process.

METHODS

C57BL/6J mice were randomized to three groups, i.e., sham-operated group, ischemia/reperfusion (I/R) group, and IPC + I/R group. Meanwhile, 3-methyladenine, an autophagy inhibitor, was administered when further verification was needed. Histological and functional severity of kidney injury, the autophagy and apoptosis activity of PTCs, as well as the characterization of the immune cell infiltration landscape in kidney tissues were investigated. Furthermore, HK-2 cells and primary cultured PTC were cultured to set up the hypoxic preconditioning and hypoxia/reoxygenation model for in vitro simulation and verification, and a microarray dataset derived from the Gene Expression Omnibus database was analyzed to explore the transcriptome profiles after IPC.

RESULTS

IPC could significantly attenuate I/R-induced kidney injury functionally and histologically both in the acute and recovery phase of RIRI by enhancing the autophagy activity of PTCs. Cell autophagy could regulate the release of monocyte chemoattractant protein-1, and sequentially decrease macrophages infiltration in kidney tissues in the acute phase of RIRI, thus mediating the reno-protective effect.

CONCLUSIONS

IPC could attenuate mouse RIRI-induced kidney injury. IPC-mediated activation of autophagy of PTCs plays a vital role in affording protection in RIRI-induced kidney injury.

Maslinic Acid Attenuates Ischemia/Reperfusion-Induced Acute Kidney Injury by Suppressing Inflammation and Apoptosis Through Inhibiting NF-κB and MAPK Signaling Pathway

Inflammation and apoptosis are the major contributors to the mechanisms of acute kidney injury (AKI) due to renal ischemia-reperfusion injury (IRI). Maslinic acid (MA), a pentacyclic triterpene acid mostly found in dietary plants, the current study was to demonstrate the renoprotective effect of MA on IRI-induced AKI, and to investigate the role of inflammation and apoptosis-related signaling pathways as a molecular mechanism. C57BL/6J mice were subjected to IRI for 72 h, and MA was daily administered by intraperitoneal injection during this period. In parallel, rat renal proximal tubule cells (NRK52E) were prophylactically treated with MA and then exposed to hydrogen peroxide (H₂O₂). MA treatment significantly inhibited the mRNA expression of interleukin (IL-1β), tumor necrosis factor-α (TGF-α), monocyte chemoattractant protein-1 (MCP-1), and intercellular adhesion molecule-1(ICAM-1). Also, MA reduced the expression of Bax/Bcl2 ratio and cleaved caspase-3. In NRK52 cells, MA inhibited the IκBα degradation, blocked NF-κB/p65 phosphorylation, and nuclear translocation. The phosphorylation of ERK, JNK, and p38 was attenuated by MA in IRI-induced kidney injury and H₂O₂-stimulated NRK52 cells. The expression levels of IL-1β, MCP-1, and ICAM-1 were upregulated in H₂O₂-stimulated NRK52E cells, which was attenuated by NF-κB inhibitor. H₂O₂ treatment increased the Bax/Bcl2 ratio and cleaved caspase-3 in NRK52E cells, which was counteracted by MAPK inhibitors. Together, our data demonstrate that MA suppresses IR-induced AKI injury through NF-κB and MAPK signaling pathways and that MA is a promising agent in the treatment of kidney diseases.

Bone Marrow Mononuclear Cells Restore Normal Mitochondrial Ca2+ Handling and Ca2+-Induced Depolarization of the Internal Mitochondrial Membrane by Inhibiting the Permeability Transition Pore After Ischemia/Reperfusion

Acute kidney injury due to ischemia followed by reperfusion (IR) is a severe clinical condition with high death rates. IR affects the proximal tubule segments due to their predominantly oxidative metabolism and profoundly altered mitochondrial functions. We previously described the impact of IR on oxygen consumption, the generation of membrane potential (ΔΨ), and formation of reactive oxygen species, together with inflammatory and structural alterations. We also demonstrated the benefits of bone marrow mononuclear cells (BMMC) administration in these alterations. The objective of the present study has been to investigate the effect of IR and the influence of BMMC on the mechanisms of Ca²⁺ handling in mitochondria of the proximal tubule cells. IR inhibited the rapid accumulation of Ca²⁺ (Ca²⁺ green fluorescence assays) and induced the opening of the cyclosporine A-sensitive permeability transition pore (PTP), alterations prevented by BMMC. IR accelerated Ca²⁺-induced decrease of ΔΨ (Safranin O fluorescence assays), as evidenced by decreased requirement for Ca²⁺ load and t_1/2 for complete depolarization. Addition of BMMC and ADP recovered the normal depolarization profile, suggesting that stabilization of the adenine nucleotide translocase (ANT) in a conformation that inhibits PTP opening offers a partial defense mechanism against IR injury. Moreover, as ANT forms a complex with the voltage-dependent anion channel (VDAC) in the outer mitochondrial membrane, it is possible that this complex is also a target for IR injury—thus favoring Ca²⁺ release, as well as the supramolecular structure that BMMC protects. These beneficial effects are accompanied by a stimulus of the citric acid cycle—which feed the mitochondrial complexes with the electrons removed from different substrates—as the result of accentuated stimulus of citrate synthase activity by BMMC.

MCP-1: Function, regulation, and involvement in disease

MCP-1 (Monocyte chemoattractant protein-1), also known as Chemokine (CC-motif) ligand 2 (CCL2), is from family of CC chemokines. It has a vital role in the process of inflammation, where it attracts or enhances the expression of other inflammatory factors/cells. It leads to the advancement of many disorders by this main mechanism of migration and infiltration of inflammatory cells like monocytes/macrophages and other cytokines at the site of inflammation. MCP-1 has been inculpated in the pathogenesis of numerous disease conditions either directly or indirectly like novel corona virus, cancers, neuroinflammatory diseases, rheumatoid arthritis, cardiovascular diseases. The elevated MCP-1 level has been observed in COVID-19 patients and proven to be a biomarker associated with the extremity of disease along with IP-10. This review will focus on involvement and role of MCP-1 in various pathological conditions.

MicroRNA as a Potential Biomarker and Treatment Strategy for Ischemia-Reperfusion Injury

Ischemia-reperfusion (I/R) injury is a progressive injury that aggravates the pathological state when the organ tissue restores blood supply after a certain period of ischemia, including the myocardial, brain, liver, kidney, and intestinal. With growing evidence that microRNAs (miRNAs) play an important role as posttranscription gene silencing mediators in many I/R injury, in this review, we highlight the microRNAs that are related to I/R injury and their regulatory molecular pathways. In addition, we discussed the potential role of miRNA as a biomarker and its role as a target in I/R injury treatment. Developing miRNAs are not without its challenges, but prudent design combined with existing clinical treatments will result in more effective therapies for I/R injury. This review is aimed at providing new research results obtained in this research field. It is hoped that new research on this topic will not only generate new insights into the pathophysiology of miRNA in I/R injury but also can provide a basis for the clinical application of miRNA in I/R.

Study of the Role of the Tyrosine Kinase Receptor MerTK in the Development of Kidney Ischemia-Reperfusion Injury in RCS Rats

Renal ischaemia reperfusion (I/R) triggers a cascade of events including oxidative stress, apoptotic body and microparticle (MP) formation as well as an acute inflammatory process that may contribute to organ failure. Macrophages are recruited to phagocytose cell debris and MPs. The tyrosine kinase receptor MerTK is a major player in the phagocytosis process. Experimental models of renal I/R events are of major importance for identifying I/R key players and for elaborating novel therapeutical approaches. A major aim of our study was to investigate possible involvement of MerTK in renal I/R. We performed our study on both natural mutant rats for MerTK (referred to as RCS) and on wild type rats referred to as WT. I/R was established by of bilateral clamping of the renal pedicles for 30' followed by three days of reperfusion. Plasma samples were analysed for creatinine, aspartate aminotransferase (ASAT), lactate dehydrogenase (LDH), kidney injury molecule -1 (KIM-1), and neutrophil gelatinase-associated lipocalin (NGAL) levels and for MPs. Kidney tissue damage and CD68-positive cell requirement were analysed by histochemistry. monocyte chemoattractant protein-1 (MCP-1), myeloperoxidase (MPO), inducible nitric oxide synthase (iNOS), and histone 3A (H3A) levels in kidney tissue lysates were analysed by western blotting. The phagocytic activity of blood-isolated monocytes collected from RCS or WT towards annexin-V positive bodies derived from cultured renal cell was assessed by fluorescence-activated single cell sorting (FACS) and confocal microscopy analyses. The renal I/R model for RCS rat described for the first time here paves the way for further investigations of MerTK-dependent events in renal tissue injury and repair mechanisms.

SIX1 Activation Is Involved in Cell Proliferation, Migration, and Anti-inflammation of Acute Ischemia/Reperfusion Injury in Mice

Nephrogenic proteins are re-expressed after ischemia/reperfusion (I/R) injury; however, the role of these proteins is still unknown. We found that sine oculis homeobox 1 (SIX1), a developmentally regulated homeoprotein, is reactivated in tubular epithelial cells after I/R injury associated with cell proliferation/migration and anti-inflammation. We demonstrated that SIX1 promoted cell proliferation by upregulating cyclin and glycolytic genes, and might increase cell migration by upregulating the expression of matrix metalloproteinase 9 (MMP9) directly or indirectly in the cell model. Notably, SIX1 targeted the promoters of the amino-terminal enhancer of split (AES) and fused in sarcoma (FUS), which are cofactors of nuclear factor-κB (NF-κB) subunit RELA, and then inhibited the transactivation function of RELA. The expression of monocyte chemotactic protein-1 (MCP-1) was decreased by the SIX1-mediated NF-κB pathway. Our results showed that the expression of cyclin, glycolytic genes, and MMP9 were significantly increased, and the infiltration of monocytes/macrophages (Mophs) was suppressed in SIX1 overexpression kidney at 1, 2, and 3 days after reperfusion. The overexpression of SIX1 resulted in reducing kidney damage from I/R injury in mice by promoting cell proliferation and migration and by inhibiting inflammation. Our study provides evidence that SIX1 involved in cell proliferation, migration, and anti-inflammation in the I/R model, which might be a potential therapeutic target that could be used to ameliorate kidney damage.

The Entry and Egress of Monocytes in Atherosclerosis: A Biochemical and Biomechanical Driven Process

In accordance with “the response to injury” theory, the entry of monocytes into the intima guided by inflammation signals, taking up cholesterol and transforming into foam cells, and egress from plaques determines the progression of atherosclerosis. Multiple cytokines and receptors have been reported to be involved in monocyte recruitment such as CCL2/CCR2, CCL5/CCR5, and CX3CL1/CX3CR1, and the egress of macrophages from the plaque like CCR7/CCL19/CCL21. Interestingly, some neural guidance molecules such as Netrin-1 and Semaphorin 3E have been demonstrated to show an inhibitory effect on monocyte migration. During the processes of monocytes recruitment and migration, factors affecting the biomechanical properties (e.g., the membrane fluidity, the deformability, and stiffness) of the monocytes, like cholesterol, amyloid-β peptide (Aβ), and lipopolysaccharides (LPS), as well as the biomechanical environment that the monocytes are exposed, like the extracellular matrix stiffness, mechanical stretch, blood flow, and hypertension, were discussed in the latter section. Till now, several small interfering RNAs (siRNAs), monoclonal antibodies, and antagonists for CCR2 have been designed and shown promising efficiency on atherosclerosis therapy. Seeking more possible biochemical factors that are chemotactic or can affect the biomechanical properties of monocytes, and uncovering the underlying mechanism, will be helpful in future studies.

Potential Biomarkers in Diagnosis of Renal Acanthamoebiasis

Recent studies indicate that Acanthamoeba spp. may play a significant role in kidney dysfunction. The aim of the study was to examine the levels of kidney injury molecule 1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), and monocyte chemotactic protein 1 (MCP-1), as well as an activity of matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9, respectively) in the kidneys of immunocompetent and immunosuppressed mice infected with Acanthamoeba spp. The levels of KIM-1, NGAL, and MCP-1 were analyzed by enzyme-linked immunosorbent assay (ELISA), and the activity of MMPs was determined by gelatin zymography. The elevated KIM-1 level was found in the kidneys of immunocompetent mice at the beginning of Acanthamoeba spp. infection. In the immunosuppressed mice, the KIM-1 level was statistically different. The statistically decreased NGAL level was found in the kidneys of immunocompetent mice compared to the uninfected mice. In the immunocompromised mice, we found statistically significant differences in MCP-1 levels between the uninfected and infected groups. There was an increase in the expression of both MMP-2 and MMP-9 in the kidneys of immunocompetent and immunosuppressed mice infected with Acanthamoeba spp. compared to the uninfected mice. The results indicate that KIM-1, NGAL, MCP-1, MMP-2, MMP-9, and MMP-9/NGAL might be promising biomarkers of renal acanthamoebiasis.

Improvement of Islet Allograft Function Using Cibinetide, an Innate Repair Receptor Ligand

BACKGROUND

During intraportal pancreatic islet transplantation (PITx), early inflammatory reactions cause an immediate loss of more than half of the transplanted graft and potentiate subsequent allograft rejection. Previous findings suggest that cibinetide, a selective innate repair receptor agonist, exerts islet protective and antiinflammatory properties and improved transplant efficacy in syngeneic mouse PITx model. In a stepwise approach toward a clinical application, we have here investigated the short- and long-term effects of cibinetide in an allogeneic mouse PITx model.

METHODS

Streptozotocin-induced diabetic C57BL/6N (H-2) mice were transplanted with 320 (marginal) or 450 (standard) islets from BALB/c (H-2) mice via the portal vein. Recipients were treated perioperative and thereafter daily during 14 d with cibinetide (120 µg/kg), with or without tacrolimus injection (0.4 mg/kg/d) during days 4-14 after transplantation. Graft function was assessed using nonfasting glucose measurements. Relative gene expressions of proinflammatory cytokines and proinsulin of the graft-bearing liver were assessed by quantitative polymerase chain reaction. Cibinetide's effects on dendritic cell maturation were investigated in vitro.

RESULTS

Cibinetide ameliorated the local inflammatory responses in the liver and improved glycemic control immediately after allogeneic PITx and significantly delayed the onset of allograft loss. Combination treatment with cibinetide and low-dose tacrolimus significantly improved long-term graft survival following allogeneic PITx. In vitro experiments indicated that cibinetide lowered bone-marrow-derived-immature-dendritic cell maturation and subsequently reduced allogeneic T-cell response.

CONCLUSIONS

Cibinetide reduced the initial transplantation-related severe inflammation and delayed the subsequent alloreactivity. Cibinetide, in combination with low-dose tacrolimus, could significantly improve long-term graft survival in allogeneic PITx.

Conditioned Medium from Human Amnion-Derived Mesenchymal Stromal/Stem Cells Attenuating the Effects of Cold Ischemia-Reperfusion Injury in an In Vitro Model Using Human Alveolar Epithelial Cells

The clinical results of lung transplantation (LTx) are still less favorable than other solid organ transplants in both the early and long term. The fragility of the lungs limits the procurement rate and can favor the occurrence of ischemia-reperfusion injury (IRI). Ex vivo lung perfusion (EVLP) with Steen Solution^TM (SS) aims to address problems, and the implementation of EVLP to alleviate the activation of IRI-mediated processes has been achieved using mesenchymal stromal/stem cell (MSC)-based treatments. In this study, we investigated the paracrine effects of human amnion-derived MSCs (hAMSCs) in an in vitro model of lung IRI that includes cold ischemia and normothermic EVLP. We found that SS enriched by a hAMSC-conditioned medium (hAMSC-CM) preserved the viability and delayed the apoptosis of alveolar epithelial cells (A549) through the downregulation of inflammatory factors and the upregulation of antiapoptotic factors. These effects were more evident using the CM of 3D hAMSC cultures, which contained an increased amount of immunosuppressive and growth factors compared to both 2D cultures and encapsulated-hAMSCs. To conclude, we demonstrated an in vitro model of lung IRI and provided evidence that a hAMSC-CM attenuated IRI effects by improving the efficacy of EVLP, leading to strategies for a potential implementation of this technique.

Ischemia-Reperfusion Injury Reduces Kidney Folate Transporter Expression and Plasma Folate Levels

Acute or chronic kidney disease can cause micronutrient deficiency. Patients with end-stage renal disease, kidney transplantation or on dialysis have reduced circulating levels of folate, an essential B vitamin. However, the molecular mechanism is not well understood. Reabsorption of folate in renal proximal tubules through folate transporters is an important process to prevent urinary loss of folate. The present study investigated the impact of acute kidney injury (AKI) on folate transporter expression and the underlying mechanism. AKI was induced in Sprague-Dawley rats that were subjected to kidney ischemia (45 min)-reperfusion (24 h). Both male and female rats displayed kidney injury and low plasma folate levels compared with sham-operated rats. The plasma folate levels were inversely correlated to plasma creatinine levels. There was a significant increase in neutrophil gelatinase-associated lipocalin (NGAL) and IL-6 mRNA expression in the kidneys of rats with ischemia-reperfusion, indicating kidney injury and increased inflammatory cytokine expression. Ischemia-reperfusion decreased mRNA and protein expression of folate transporters including folate receptor 1 (FOLR1) and reduced folate carrier (RFC); and inhibited transcription factor Sp1/DNA binding activity in the kidneys. Simulated ischemia-reperfusion through hypoxia-reoxygenation or Sp1 siRNA transfection in human proximal tubular cells inhibited folate transporter expression and reduced intracellular folate levels. These results suggest that ischemia-reperfusion injury downregulates renal folate transporter expression and decreases folate uptake by tubular cells, which may contribute to low folate status in AKI. In conclusion, ischemia-reperfusion injury can downregulate Sp1 mediated-folate transporter expression in tubular cells, which may reduce folate reabsorption and lead to low folate status.

Inhibition of BRD4 Reduces Neutrophil Activation and Adhesion to the Vascular Endothelium Following Ischemia Reperfusion Injury

Renal ischemia reperfusion injury (IRI) is associated with inflammation, including neutrophil infiltration that exacerbates the initial ischemic insult. The molecular pathways involved are poorly characterized and there is currently no treatment. We performed an in silico analysis demonstrating changes in NFκB-mediated gene expression in early renal IRI. We then evaluated NFκB-blockade with a BRD4 inhibitor on neutrophil adhesion to endothelial cells in vitro, and tested BRD4 inhibition in an in vivo IRI model. BRD4 inhibition attenuated neutrophil adhesion to activated endothelial cells. In vivo, IRI led to increased expression of cytokines and adhesion molecules at 6 h post-IRI with sustained up-regulated expression to 48 h post-IRI. These effects were attenuated, in part, with BRD4 inhibition. Absolute neutrophil counts increased significantly in the bone marrow, blood, and kidney 24 h post-IRI. Activated neutrophils increased in the blood and kidney at 6 h post-IRI and remained elevated in the kidney until 48 h post-IRI. BRD4 inhibition reduced both total and activated neutrophil counts in the kidney. IRI-induced tubular injury correlated with neutrophil accumulation and was reduced by BRD4 inhibition. In summary, BRD4 inhibition has important systemic and renal effects on neutrophils, and these effects are associated with reduced renal injury.

Molecular targeting of renal inflammation using drug delivery technology to inhibit NF-κB improves renal recovery in chronic kidney disease

Inflammation is a major determinant for the progression of chronic kidney disease (CKD). NF-κB is a master transcription factor upregulated in CKD that promotes inflammation and regulates apoptosis and vascular remodeling. We aimed to modulate this pathway for CKD therapy in a swine model of CKD using a peptide inhibitor of the NF-κB p50 subunit (p50i) fused to a protein carrier [elastin-like polypeptide (ELP)] and equipped with a cell-penetrating peptide (SynB1). We hypothesized that intrarenal SynB1-ELP-p50i therapy would inhibit NF-κB-driven inflammation and induce renal recovery. CKD was induced in 14 pigs. After 6 wk, pigs received single intrarenal SynB1-ELP-p50i therapy (10 mg/kg) or placebo (n = 7 each). Renal hemodynamics were quantified in vivo using multidetector computed tomography before and 8 wk after treatment. Pigs were then euthanized. Ex vivo experiments were performed to quantify renal activation of NF-κB, expression of downstream mediators of NF-κB signaling, renal microvascular density, inflammation, and fibrosis. Fourteen weeks of CKD stimulated NF-κB signaling and downstream mediators (e.g., TNF-α, monocyte chemoattractant protein-1, and IL-6) accompanying loss of renal function, inflammation, fibrosis, and microvascular rarefaction versus controls. All of these were improved after SynB1-ELP-p50i therapy, accompanied by reduced circulating inflammatory cytokines as well, which were evident up to 8 wk after treatment. Current treatments for CKD are largely ineffective. Our study shows the feasibility of a new treatment to induce renal recovery by offsetting inflammation at a molecular level. It also supports the therapeutic potential of targeted inhibition of the NF-κB pathway using novel drug delivery technology in a translational model of CKD.

Kidney Ischemia-Reperfusion Elicits Acute Liver Injury and Inflammatory Response

Ischemia-reperfusion (IR) is a common risk factor that causes acute kidney injury (AKI). AKI is associated with dysfunction of other organs also known as distant organ injury. The liver function is often compromised in patients with AKI and in animal models. However, the underlying mechanisms are not fully understood. Inflammatory response plays an important role in IR-induced tissue injury. Although increased proinflammatory cytokines have been detected in the kidney and the distant organs after renal IR, their original sources remain uncertain. In the present study, we investigated the acute effect of renal IR on hepatic inflammatory cytokine expression and the mechanism involved. Sprague-Dawley rats that were subjected to renal IR (ischemia for 45 min followed by reperfusion for 1 h or 6 h) had increased plasma levels of creatinine, urea, and transaminases, indicating kidney and liver injuries. There was a significant increase in the expression of proinflammatory cytokine mRNA (MCP-1, TNF-α, IL-6) in the kidney and liver in rats with renal IR. This was accompanied by a significant increase in proinflammatory cytokine protein levels in the plasma, kidney, and liver. Activation of a nuclear transcription factor kappa B (NF-κB) was detected in the liver after renal IR. The inflammatory foci and an increased myeloperoxidase (MPO) activity were detected in the liver after renal IR, indicating hepatic inflammatory response and leukocyte infiltration. These results suggest that renal IR can directly activate NF-κB and induce acute production of proinflammatory cytokines in the liver. Renal IR-induced hepatic inflammatory response may contribute to impaired liver function and systemic inflammation.

Role of SET7/9 in the progression of ischemic renal injury in diabetic and non-diabetic rats

SET domain with lysine methyltransferase 7/9 (Set7/9), a histone lysine methyltransferase (HMT), recently suggested to exert a critical role among kidney disorders, whereas its role in diabetes associated IRI co-morbidity remains complete elusive. The present study aimed to understand the role of SET7/9 and histone methylation in regulation of inflammatory signaling under IRI in diabetes mellitus and non-diabetic rats. Our results demonstrated that IRI caused renal dysfunction via increased blood urea nitrogen (BUN) levels in ND and DM rats. The NF-κB mediated inflammatory cascade like increased p-NF-κB, reduced IκBα levels followed by enhanced leukocyte infiltration as shown by increased MCP-1 expressions. IRI results in increased histone H3 methylation at lysine 4 and 36 (H3K4Me2, H3K36Me2), and decreased histone H3 methylation at lysine 9. Additionally, IRI increased the protein and mRNA expression of H3K4Me2 specific histone methyltransferase-SET7/9 in DM and ND rats. The abovementioned results remain prominent in DM rats compared to ND rats followed by IRI. Further, treatment with a novel SET7/9 inhibitor; cyproheptadine, significantly improved renal functioning via reducing the BUN levels in ND and DM rats. Hence, this study demonstrated the role of SET7/9 in mediating active transcription via H3K4Me2, ultimately regulated the NFκB-mediated inflammatory cascade. Therefore, SET7/9 can be explored as novel target for drug development against IRI under DM and ND conditions.

Inhibition of Inflammatory Cytokine Expression Prevents High-Fat Diet-Induced Kidney Injury: Role of Lingonberry Supplementation

Chronic low-grade inflammation is a major stimulus for progression of chronic kidney disease (CKD) in individuals consuming high-fat diet. Currently, there are limited treatment options for CKD other than controlling the progression rate and its associated complications. Lingonberry (Vaccinium vitis-idaea L.) is rich in anthocyanins with demonstrated anti-inflammatory effect. In the current study, we investigated the potential renal protective effect of lingonberry and its anthocyanin (cyanidin-3-glucoside) in high-fat diet fed obese mice and in human proximal tubular cells. Prolonged consumption of high-fat diets is strongly associated with obesity, abnormal lipid and glucose metabolism. Mice (C57BL/6J) fed a high-fat diet (62% kcal fat) for 12 weeks developed renal injury as indicated by an elevation of blood urea nitrogen (BUN) level as well as an increase in renal kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL) and renin expression. Those mice displayed an activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and increased expression of inflammatory cytokines-monocyte chemoattractant-1 (MCP-1), tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6) in the kidneys. Mice fed a high-fat diet also had a significant elevation of inflammatory cytokine levels in the plasma. Dietary supplementation of lingonberry for 12 weeks not only attenuated high-fat diet-induced renal inflammatory response but also reduced kidney injury. Such a treatment improved plasma lipid and glucose profiles, reduced plasma inflammatory cytokine levels but did not affect body weight gain induced by high-fat diet feeding. Lingonberry extract or its active component cyanidin-3-glucoside effectively inhibited palmitic acid-induced NF-κB activation and inflammatory cytokine expression in proximal tubular cells. These results suggest that lingonberry supplementation can reduce inflammatory response and prevent chronic kidney injury. Such a renal protective effect by lingonberry and its active component may be mediated, in part, through NF-κB signaling pathway.

Vagus Nerve Stimulation Ameliorates Renal Ischemia-Reperfusion Injury through Inhibiting NF-κB Activation and iNOS Protein Expression

OBJECTIVE

In renal ischemia/reperfusion injury (RIRI), nuclear factor κB (NF-κB (NF-κB (NF.

METHODS

Eighteen male Sprague-Dawley rats were randomly allocated into the sham group, the I/R group, and the VNS+I/R group, 6 rats per group. An RIRI model was induced by a right nephrectomy and blockade of the left renal pedicle vessels for 45 min. After 6 h of reperfusion, the blood samples and renal samples were collected. The VNS treatment was performed throughout the I/R process in the VNS+I/R group using specific parameters (20 Hz, 0.1 ms in duration, square waves) known to produce a small but reliable bradycardia. Blood was used for evaluation of renal function and inflammatory state. Renal injury was evaluated via TUNEL staining. Renal samples were harvested to evaluate renal oxidative stress, NF-κB (NF.

RESULTS

The VNS treatment reduces serum creatinine (Cr) and blood urea nitrogen (BUN) levels. Simultaneously, the levels of tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), and interleukin 1-beta (IL-1β) were significantly increased in the I/R group, but VNS treatment markedly ameliorated this inflammatory response. Furthermore, the VNS ameliorated oxidant stress and renal injury, indicated by a decrease in 3-nitrotyrosine (3-NT) formation and MDA and MPO levels and an increase in the SOD level compared to that in the I/R group. Finally, the VNS also significantly decreases NF-κB (NF.

CONCLUSION

Our findings indicate that NF-κB activation increased iNOS expression and promoted RIRI and that VNS treatment attenuated RIRI by inhibiting iNOS expression, oxidative stress, and inflammation via NF-κB inactivation.κB (NF-κB (NF.

Chlorogenic Acid Attenuates Kidney Ischemic/Reperfusion Injury via Reducing Inflammation, Tubular Injury, and Myofibroblast Formation

Kidney ischemic/reperfusion (I/R) injury is the main cause of acute kidney injury (AKI) involving renal function deterioration, renal architecture damage, and inflammation. This condition may lead to kidney fibrosis with epithelial to mesenchymal transition (EMT) and myofibroblast formation. Inhibition of chronic effects of kidney I/R injury may provide effective strategies for treating AKI and chronic kidney diseases (CKDs). Chlorogenic acid (CGA) is recognized as a powerful antioxidant, with anti-inflammatory and antifibrotic properties in many conditions. However, the effect of CGA on kidney I/R injury has not been elucidated yet. Kidney I/R injury was performed on male Swiss background mice (I/R group, n = 5, 3-4 months, 30–40 g) which underwent bilateral renal pedicles clamping for 30 minutes and then were euthanized on day three after operation. Three groups of I/R were treated with 3 different doses of CGA intraperitoneally for 2 days: 3.5 (I/R + CGA1 group), 7 (I/R + CGA2 group), and 14 (I/R + CGA3 group) mg/kg of body weight. Tubular injury was quantified based on Periodic Acid-Schiff staining, while reverse transcriptase PCR (RT-PCR) was performed to quantify mRNA expression of TGF-β1, vimentin, SOD-1, TLR-4, TNF-α, NF-κB and MCP-1. Immunohistochemical staining was done to quantify proliferating cell nuclear antigen (PCNA), myofibroblast (α-SMA), SOD-1 and macrophage (CD68) number. Kidney I/R demonstrated tubular injury and increased inflammatory mediator expression, macrophage number, and myofibroblast expansion. Meanwhile, histological analysis showed lower tubular injury with higher epithelial cell proliferation in CGA-treated groups compared to the I/R group. RT-PCR also revealed significantly lower TGF-β1 and vimentin mRNA expressions with higher SOD-1 mRNA expression. CGA-treated groups also demonstrated a significantly lower macrophage and myofibroblast number compared to the I/R group. These findings associated with lower mRNA expression of TLR-4, TNF-α, NF-κB, and MCP-1 as inflammatory mediators in CGA groups. I/R + CGA3 represented the highest amelioration effect among other CGA-treated groups. CGA treatment attenuates kidney I/R injury through reducing inflammation, decreasing myofibroblast expansion, and inducing epithelial cells proliferation.

Effect of steroids and relevant cytokine analysis in acute tubulointerstitial nephritis

Background

Acute tubulointerstitial nephritis (ATIN) is an important cause of acute kidney injury and often a potentially reversible disease. However, the role of steroids in ATIN remains controversial and the underlying mechanisms remain unresolved.

Methods

A total of 113 adult patients with biopsy-proven ATIN were recruited from three tertiary referral centers. Of 102 patients with idiopathic or drug-induced ATIN, outcomes such as renal recovery, end-stage renal disease, and all-cause mortality were compared between the steroid-treated and non-treated groups. Plasma and urine inflammatory cytokine levels at the time of biopsy were analyzed in patients (n = 33) using a bead-based multiplex assay and compared with those of healthy individuals (n = 40).

Results

Steroids were used in 92 (81.4%) of the total patients and in 82 (80.3%) patients with idiopathic or drug-induced ATIN. The rate of renal recovery and the risks of end-stage renal disease and mortality were not different between the steroid-treated and non-treated groups. Despite using a propensity score matching method (n = 20 in each group), none of the outcomes were different between the two groups. Several cytokines, such as monocyte chemotactic protein-1, interferon-α, and interleukin-6 and interleukin-8 levels, were markedly elevated in plasma and urine of patients compared with those in healthy individuals. However, cytokines related to Th2 response, such as IL-10, IL-33, were not different between the two groups.

Conclusions

Steroid use does not affect the overall outcome of ATIN. Based on the fact that targeting therapy should be investigated to improve outcomes, the present cytokine results will be helpful for developing a novel therapy for ATIN.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1277-2) contains supplementary material, which is available to authorized users.

Cytokines and Abnormal Glucose and Lipid Metabolism

Clear evidence indicates that cytokines, for instance, adipokines, hepatokines, inflammatory cytokines, myokines, and osteokines, contribute substantially to the development of abnormal glucose and lipid metabolism. Some cytokines play a positive role in metabolism action, while others have a negative metabolic role linking to the induction of metabolic dysfunction. The mechanisms involved are not fully understood, but are associated with lipid accumulation in organs and tissues, especially in the adipose and liver tissue, changes in energy metabolism, and inflammatory signals derived from various cell types, including immune cells. In this review, we describe the roles of certain cytokines in the regulation of metabolism and inter-organ signaling in regard to the pathophysiological aspects. Given the disease-related changes in circulating levels of relevant cytokines, these factors may serve as biomarkers for the early detection of metabolic disorders. Moreover, based on preclinical studies, certain cytokines that can induce improvements in glucose and lipid metabolism and immune response may emerge as novel targets of broader and more efficacious treatments and prevention of metabolic disease.

Initiation of the inflammatory response after renal ischemia/reperfusion injury during renal transplantation

Ischemia/reperfusion injury (IRI) occurs commonly during renal transplantation. It has been well demonstrated that the inflammatory response has an important role in the pathogenesis and pathological processes of IRI. However, the signaling events that trigger the activation of the inflammatory response are less clear. Accumulated evidence has identified the role of various injury factors released from or exposed in ischemic, damaged, or dying cells, which serve as initiators of the inflammatory response and exacerbate kidney injury after renal IRI. Signaling pathways triggered by these endogenous molecules that activate different pathogen recognition receptors have also been widely investigated. Here, we review the molecular signaling molecules that initiate the inflammatory response during renal IRI and that provide potential therapeutic options for the disease.

Sources of free radicals and oxidative stress in the oral cavity

OBJECTIVE

An oral cavity is a place especially susceptible to oxidative damage. It is subjected to many environmental pro-oxidative factors or factors that have the ability to generate reactive oxygen species (ROS). The aim of this article is to present the main sources of ROS and oxidative stress in the oral environment.

DESIGN

A literature search was performed using the PubMed and Google Scholar databases.

RESULTS

One of the most important ROS sources in the oral cavity is periodontal inflammation. Other sources of ROS include: xenobiotics (ethanol, cigarette smoke, drugs), food (high-fat diet, high-protein diet, acrolein), dental treatment (ozone, ultrasound, non-thermal plasma, laser light, ultraviolet light), and dental materials (fluorides, dental composites, fixed orthodontic appliances, and titanium fixations). It has been shown that excessive production of ROS in the oral cavity may cause oxidative stress and oxidative damage to cellular DNA, lipids, and proteins, thus predisposing to many oral and systemic diseases.

CONCLUSIONS

Recognition of the exogenous sources of ROS and limitation of exposure to the ROS generating factors can be one of the prophylactic measures preventing oral and systemic diseases. It is suggested that antioxidant supplementation may be helpful in people exposed to excessive production of ROS in the oral cavity system.

Protective action of Crateva nurvala Buch. Ham extracts against renal ischaemia reperfusion injury in rats via antioxidant and anti-inflammatory activities

ETHNOPHARMACOLOGICAL RELEVANCE

Crateva nurvala stem bark is commonly used in Ayruveda in treatment of many renal injuries, e.g., urinary lithiasis, diuretic and nephroprotective. However, its protective effect against renal ischaemia/reperfusion, the major cause of acute kidney injury, has never been studied. Moreover, no comprehensive chemical profiling of its extracts was recorded.

AIM OF THE STUDY

Assessment of the protective effect of the plant extracts against renal ischaemia/reperfusion and elucidation of the possible mechanism of action. Then, to determine its bioactive constituents using modern UPLC-HRMS technique.

MATERIAL AND METHODS

Unilateral ischaemia was induced by clamping the left renal artery for 1h then reperfusion for 24h. Rats were divided in 4 groups: i) sham-operated group, ii) ischaemia/reperfusion, I/R group, iii) I/R protected by previous administration of Crateva leaves extract, CLE group and iv) I/R protected by previous administration of Crateva bark extract, CBE group. At the end of reperfusion, blood samples were analyzed for renal function biomarkers. Kidneys were examined histopathologically and their homogenates were used in determining the intracellular levels of oxidative stress, inflammatory, and apoptosis markers.

RESULTS

Leaves and bark extracts attenuated the deleterious effects of I/R apparent in reducing LDH, creatinine and blood urea nitrogen levels. The extracts reduced the oxidative stress by replenishing the glutathione levels and Nrf2 factor levels. Moreover, extracts decreased levels of pro-inflammatory TNF-α, NF-κβ and IL-6; which ultimately resulted in reducing the pro-apoptotic caspase-3. Bark and leave extracts have quite similar chemical profile where 42 compounds of various chemical classes were identified. Flavonoids are the major class of the bioactive phytochemicals CONCLUSION: C. nurvala extracts had effectively ameliorated the deleterious effects of renal I/R by mainly counteracting oxidative stress and presumably inflammation. Consequently, it can be used as a complementary treatment with other agents. In this aspect, leaves stand as a sustainable alternative to bark. The presented chemical profiling can be used in future standardization and quality control of the drug.

Nutrients and Oxidative Stress: Friend or Foe?

There are different types of nutritionally mediated oxidative stress sources that trigger inflammation. Much information indicates that high intakes of macronutrients can promote oxidative stress and subsequently contribute to inflammation via nuclear factor-kappa B- (NF-κB-) mediated cell signaling pathways. Dietary carbohydrates, animal-based proteins, and fats are important to highlight here because they may contribute to the long-term consequences of nutritionally mediated inflammation. Oxidative stress is a central player of metabolic ailments associated with high-carbohydrate and animal-based protein diets and excessive fat consumption. Obesity has become an epidemic and represents the major risk factor for several chronic diseases, including diabetes, cardiovascular disease (CVD), and cancer. However, the molecular mechanisms of nutritionally mediated oxidative stress are complex and poorly understood. Therefore, this review aimed to explore how dietary choices exacerbate or dampen the oxidative stress and inflammation. We also discussed the implications of oxidative stress in the adipocyte and glucose metabolism and obesity-associated noncommunicable diseases (NCDs). Taken together, a better understanding of the role of oxidative stress in obesity and the development of obesity-related NCDs would provide a useful approach. This is because oxidative stress can be mediated by both extrinsic and intrinsic factors, hence providing a plausible means for the prevention of metabolic disorders.

Vascular Remodeling, Oxidative Stress, and Disrupted PPARγ Expression in Rats of Long-Term Hyperhomocysteinemia with Metabolic Disturbance

Hyperhomocysteinemia, a risk factor for vascular disease, is associated with metabolic syndrome. Our study was aimed at exploring the effect of long-term hyperhomocysteinemia with metabolic disturbances on vascular remodeling. We also studied oxidative stress and expression of PPARγ in the coronary arteriole as a possible mechanism underlying vascular remodeling. Rats were treated with standard rodent chow (Control) or diet enriched in methionine (Met) for 48 weeks. Plasma homocysteine, blood glucose, serum lipids, malondialdehyde (MDA), superoxide dismutase (SOD), and nitric oxide (NO) levels were measured. Coronary arteriolar and carotid arterial remodeling was assessed by histomorphometric techniques and the expression of PPARγ in vessel wall was investigated. In Met group, an increase in the level of fasting blood glucose, serum triglyceride, total cholesterol, MDA, and NO, a decline in the serum SOD level, and increased collagen deposition in coronary and carotid arteries were found. Moreover, we detected decreased expression of PPARγ in the coronary arterioles in Met group. In summary, our study revealed metabolic disturbances in this model of long-term hyperhomocysteinemia together with vascular remodeling and suggested that impaired oxidative stress, endothelium dysfunction, and decreased PPARγ expression in the vessel wall could be underlying mechanisms.

Podocyte NF-κB is dispensable for the pathogenesis of renal ischemia-reperfusion injury

Podocytes play a central role in the formation of the glomerular filtration barrier in the kidney, and their dysfunction has been shown to result in multiple proteinuric kidney diseases. In this study, we sought to determine whether NF-κB, a proinflammatory signaling, within podocytes was involved in renal ischemia-reperfusion (I/R) injury. Podocyte-specific IκBΔN transgenic (Pod-IκBΔN) mice, in which NF-κB was inhibited specifically in podocytes, were generated by the Cre-loxP technology, and their phenotype was compared with control mice after bilateral renal ischemia. The effect of systemic administration of a NF-κB inhibitor, pyrrolidinedithiocarbamate (PDTC), on renal I/R injury was also examined. Pod-IκBΔN mice were phenotypically normal before surgery. Following renal I/R injury, serum concentrations of urea nitrogen and creatinine were elevated in both Pod-IκBΔN and control mice to a similar extent, whereas PDTC treatment attenuated the elevation of these parameters. Renal histological damage in I/R-injured Pod-IκBΔN mice was also similar to I/R-injured control mice, although it was improved by PDTC treatment. Moreover, I/R induced accumulation of inflammatory cells, such as neutrophils and macrophages, was reduced by PDTC treatment, but not by podocyte-specific NF-κB inhibition. These results provide evidence that the NF-κB activity in podocytes does not contribute to the pathogenesis of renal I/R injury.

Supplementing diet with Manitoba lingonberry juice reduces kidney ischemia-reperfusion injury

BACKGROUND

Lingonberry (Vaccinium vitis-idaea L.) contains high levels of anthocyanins which are bioavailable in the kidney and may be protective against ischemia-reperfusion (IR)-induced acute kidney injury. This study investigated the effect of lingonberry juice on the IR-induced stress-activated signalling pathway and inflammatory response in the kidney.

RESULTS

Sprague-Dawley rats subjected to kidney IR had significantly impaired kidney function, with increased activation of the JNK signalling pathway and increased inflammatory response, measured using a multiplex panel containing an extensive array of inflammatory biomarkers. In rats fed 1 mL lingonberry juice daily for 3 weeks prior to IR, kidney function was protected and attenuation of inflammatory response and JNK signalling was reflected in the reduction of the measured biomarkers. In vitro results in cultured HK-2 cells confirmed that lingonberry anthocyanins reduced JNK signalling and inflammatory gene expression after IR.

CONCLUSION

This study shows, for the first time, that daily supplementation with lingonberry juice may protect against loss of kidney function induced by IR injury by modulating JNK signalling and inhibiting the subsequent inflammatory response. © 2017 Her Majesty the Queen in Right of Canada. Journal of the Science of Food and Agriculture © 2017 Society of Chemical Industry.

The Redox Balance in Erythrocytes, Plasma, and Periosteum of Patients with Titanium Fixation of the Jaw

Titanium miniplates and screws are commonly used for fixation of jaw fractured or osteotomies. Despite the opinion of their biocompatibility, in clinical practice symptoms of chronic inflammation around the fixation develop in some patients, even many years after the application of miniplates and screws. The cause of these complications is still an unanswered question. Taking into account that oxidative stress is one of the toxic action of titanium, we have evaluated the antioxidant barrier as well as oxidative stress in the erythrocytes, plasma and periosteum covering the titanium fixation of the jaw. The study group was composed of 32 patients aged 20–30 with inserted miniplates and screws. The antioxidant defense: catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase-1 (SOD1), uric acid (UA), total antioxidant capacity (TAC), as well as oxidative damage products: advanced oxidation protein products (AOPP), advanced glycation end products (AGE), dityrosine, kynurenine, N-formylkynurenine, tryptophan, malondialdehyde (MDA), 4-hydroxynonenal (4-HNE), total oxidant status (TOS), and oxidative status index (OSI) were evaluated. SOD1 activity (↓37%), and tryptophan levels (↓34%) showed a significant decrease while AOPP (↑25%), TOS (↑80%) and OSI (↑101%) were significantly elevated in maxillary periosteum of patients who underwent bimaxillary osteotomies as compared to the control group. SOD-1 (↓55%), TAC (↓58.6%), AGE (↓60%) and N-formylkynurenine (↓34%) was statistically reduced while AOPP (↑38%), MDA (↑29%), 4-HNE (↑114%), TOS (↑99%), and OSI (↑381%) were significantly higher in the mandibular periosteum covering miniplates/screw compared with the control tissues. There were no correlations between antioxidants and oxidative stress markers in the periosteum of all patients and the blood. As exposure to the Ti6Al4V titanium alloy leads to disturbances of redox balance in the periosteum surrounding titanium implants of the maxilla and the mandible so antioxidant supplementation should be recommended to the patients undergoing treatment of dentofacial deformities with the use of titanium implants. The results we obtained may also indicate a need to improve the quality of titanium jaw fixations through increase of TiO₂ passivation layer thickness or to develop new, the most highly biodegradable materials for their production.

Innate Immune Response in Kidney Ischemia/Reperfusion Injury: Potential Target for Therapy

Acute kidney injury caused by ischemia and subsequent reperfusion is associated with a high rate of mortality and morbidity. Ischemia/reperfusion injury in kidney transplantation causes delayed graft function and is associated with more frequent episodes of acute rejection and progression to chronic allograft nephropathy. Alloantigen-independent inflammation is an important process, participating in pathogenesis of injurious response, caused by ischemia and reperfusion. This innate immune response is characterized by the activity of classical cells belonging to the immune system, such as neutrophils, macrophages, dendritic cells, lymphocytes, and also tubular epithelial cells and endothelial cells. These immune cells not only participate in inflammation after ischemia exerting detrimental influence but also play a protective role in the healing response from ischemia/reperfusion injury. Delineating of complex mechanisms of their actions could be fruitful in future prevention and treatment of ischemia/reperfusion injury. Among numerous so far conducted experiments, observed immunomodulatory role of adenosine and adenosine receptor agonists in complex interactions of dendritic cells, natural killer T cells, and T regulatory cells is emphasized as promising in the treatment of kidney ischemia/reperfusion injury. Potential pharmacological approaches which decrease NF-κB activity and antagonize mechanisms downstream of activated Toll-like receptors are discussed.

Severe bilateral ischemic-reperfusion renal injury: hyperacute and acute changes in apparent diffusion coefficient, T1, and T2 mapping with immunohistochemical correlations

The aim of this study was to investigate the hyperacute and acute changes in apparent diffusion coefficient (ADC), T1, and T2 mapping in rat kidneys after severe bilateral renal ischemic-reperfusion injury (IRI). After baseline MRI, 24 Spraque-Dawley rats with renal IRI were divided equally as group 1 (post-IRI MRI at 6 hours, days 1, 3, and 7) and groups 2, 3, and 4 (post-IRI MRI at 6 hours; 6 hours and day 1; 6 hours, days 1 and 3, respectively), while six other rats without IRI (group 5) were used as sham control. ADC, T1, and T2 values of the cortex and outer and inner stripes of outer medulla (OSOM and ISOM), and immunohistochemical studies assessing monocyte chemoattractant protein-1 (MCP-1), CD68+ cells, tubular cast formation, and collagen deposition in three zones at different time points were evaluated. Significantly reduced ADCs in OSOM and ISOM are noninvasive biomarkers denoting hyperacute damages after IRI. Linear regression analysis revealed a significant inverse correlation between 6-hour/baseline ADC ratios and MCP-1 staining (P < 0.001, r² = 0.738). ADC, T1, and T2 values are useful for assessing variable IRI changes in different layers depending on underlying microstructural and histopathological changes at different time points.

Early Macrophage Infiltration and Sustained Inflammation in Kidneys From Deceased Donors Are Associated With Long-Term Renal Function

Kidney transplants from living donors (LDs) have a better outcome than those from deceased donors (DDs). Different factors have been suggested to justify the different outcome. In this study, we analyzed the infiltration and phenotype of monocytes/macrophages and the expression of inflammatory and fibrotic markers in renal biopsy specimens from 94 kidney recipients (60 DDs and 34 LDs) at baseline and 4 months after transplantation. We evaluated their association with medium- and long-term renal function. At baseline, inflammatory gene expression was higher in DDs than in LDs. These results were confirmed by the high number of CD68-positive cells in DD kidneys, which correlated negatively with long-term renal function. Expression of the fibrotic markers vimentin, fibronectin, and α-smooth muscle actin was more elevated in biopsy specimens from DDs at 4 months than in those from LDs. Gene expression of inflammatory and fibrotic markers at 4 months and difference between 4 months and baseline correlated negatively with medium- and long-term renal function in DDs. Multivariate analysis point to transforming growth factor-β1 as the best predictor of long-term renal function in DDs. We conclude that early macrophage infiltration, sustained inflammation, and transforming growth factor-β1 expression, at least for the first 4 months, contribute significantly to the difference in DD and LD transplant outcome.

Exercise Training Attenuates the Dysregulated Expression of Adipokines and Oxidative Stress in White Adipose Tissue

Obesity-induced inflammatory changes in white adipose tissue (WAT), which caused dysregulated expression of inflammation-related adipokines involving tumor necrosis factor-α and monocyte chemoattractant protein-1, contribute to the development of insulin resistance. Moreover, current literature reports state that WAT generates reactive oxygen species (ROS), and the enhanced production of ROS in obese WAT has been closely associated with the dysregulated expression of adipokines in WAT. Therefore, the reduction in excess WAT and oxidative stress that results from obesity is thought to be one of the important strategies in preventing and improving lifestyle-related diseases. Exercise training (TR) not only brings about a decrease in WAT mass but also attenuates obesity-induced dysregulated expression of the adipokines in WAT. Furthermore, some reports indicate that TR affects the generation of oxidative stress in WAT. This review outlines the impact of TR on the expression of inflammation-related adipokines and oxidative stress in WAT.

Renal-targeting triptolide-glucosamine conjugate exhibits lower toxicity and superior efficacy in attenuation of ischemia/reperfusion renal injury in rats

AIM

We previously reported a novel triptolide (TP)-glucosamine conjugate (TPG) that specifically accumulated in kidneys and protected renal function from acute ischemia/reperfusion (I/R) injury in rats. In this study we further examined the molecular mechanisms underlying the renoprotective action of TPG.

METHODS

The renal-targeting of TPG was investigated in a human proximal renal tubular epithelial cell line (HK-2) by measuring cell uptake of TP or TPG. The effects of TP or TPG on cell cycle distribution and apoptosis rate of HK-2 cells were assessed, and the activities of caspase-3 and caspase-9 were also measured. SD rats were subjected to bilateral renal ischemia by temporarily clamping both renal pedicles. The rats were administered TP (4.17 μmol·kg-1·d-1, iv) or TPG (4.17 μmol·kg-1·d-1, iv) for 3 d before the renal surgery. The kidneys were harvested after 24 h of recovery from the surgery. The levels of oxidative stress, proinflammatory cytokines, chemotactic cytokines and intracellular adhesion molecules in kidneys were examined.

RESULTS

The uptake of TPG in HK-2 cells was 2-3 times higher than that of TP at the concentrations tested. Furthermore, TPG targeting the proximal tubules was mediated through interactions with megalin receptors. TP (40-160 nmol/L) concentration-dependently increased G2/M arrest, apoptosis and caspase-3/caspase-9 activity in HK-2 cells, whereas the same concentrations of TPG did not show those features when compared with the control group. In I/R-treated rats, TPG administration caused more robust down-regulation of proinflammatory cytokines (TNF-α, IL-6, IL-1, TGF-β) and chemotactic cytokines (MCP-1) in the kidneys compared with TP administration, suggesting the inhibition of the proliferation and accumulation of lymphocytes. And TPG administration also caused more prominent inhibition on the levels of oxidative stress and intracellular adhesion molecules in the kidneys, compared with TP administration.

CONCLUSION

The renal-targeting TPG is more effective and less toxic than TP, in amelioration of I/R-induced rat renal injury, which may provide a new avenue for the treatment of acute kidney injury.

Downregulation of Glutathione Biosynthesis Contributes to Oxidative Stress and Liver Dysfunction in Acute Kidney Injury

Ischemia-reperfusion is a common cause for acute kidney injury and can lead to distant organ dysfunction. Glutathione is a major endogenous antioxidant and its depletion directly correlates to ischemia-reperfusion injury. The liver has high capacity for producing glutathione and is a key organ in modulating local and systemic redox balance. In the present study, we investigated the mechanism by which kidney ischemia-reperfusion led to glutathione depletion and oxidative stress. The left kidney of Sprague-Dawley rats was subjected to 45 min ischemia followed by 6 h reperfusion. Ischemia-reperfusion impaired kidney and liver function. This was accompanied by a decrease in glutathione levels in the liver and plasma and increased hepatic lipid peroxidation and plasma homocysteine levels. Ischemia-reperfusion caused a significant decrease in mRNA and protein levels of hepatic glutamate-cysteine ligase mediated through the inhibition of transcription factor Nrf2. Ischemia-reperfusion inhibited hepatic expression of cystathionine γ-lyase, an enzyme responsible for producing cysteine (an essential precursor for glutathione synthesis) through the transsulfuration pathway. These results suggest that inhibition of glutamate-cysteine ligase expression and downregulation of the transsulfuration pathway lead to reduced hepatic glutathione biosynthesis and elevation of plasma homocysteine levels, which, in turn, may contribute to oxidative stress and distant organ injury during renal ischemia-reperfusion.

Bergenin attenuates renal injury by reversing mitochondrial dysfunction in ethylene glycol induced hyperoxaluric rat model

Bergenin, isolated from Bergenia ligulata is a potent antioxidant and antilithiatic agent. Present work was designed to establish the biochemical role of bergenin on mitochondrial dysfunction in the ethylene glycol induced hyperoxaluric rat model. Bergenin was administrated at a dose of 10mg/kg body wt i.p. from 14th day of establishing the 28 days hyperoxaluria rat model. α-Tocopherol was given as positive control at a dose of 100mg/kg body wt i.p. Mitochondrial dysfunction was studied by evaluating the activities of respiratory chain complexes, mitochondrial membrane potential and reactive oxygen species. Histopathological analysis of the kidney tissue was done after Pizzolato staining. Also, expression of monocyte chemoattractant protein -1(MCP-1) and kidney injury marker protein (KIM-1) were studied and the levels of IL-1β were evaluated in kidney tissue homogenate. Mitochondrial dysfunction during stone crystallization was evident by decreased activities of electron transport chain complexes I, II and IV and augmented mitochondrial oxidative stress in hyperoxaluric rats. Bergenin treatment significantly (P<0.05) restored the activities of these complexes. Moreover, it curtailed the lipid peroxidation and up regulated antioxidant levels, ameliorating the state of mitochondrial dysfunction. The protective role of bergenin was also reinforced by reducing IL-1β production and expression of KIM-1 and MCP-1 in the renal tissue. The findings of the present study provide evidence that bergenin exerted protective effects in hyperoxaluria through mitochondrial protection that involves attenuation of oxidative stress. Hence, it presented itself as an effective remedy in combating urolithiasis.