Allopurinol Protective Effect of Renal Ischemia by Downregulating TNF-α, IL-1β, and IL-6 Response

Advancements in the study of IL-6 and its receptors in the pathogenesis of gout

Gout is an autoinflammatory disease characterized by the deposition of monosodium urate crystals in or around the joints, primarily manifesting as inflammatory arthritis that recurs and resolves spontaneously. Interleukin-6 (IL-6) is a versatile cytokine with both anti-inflammatory and pro-inflammatory capabilities, linked to a variety of inflammatory diseases such as gouty arthritis, rheumatoid arthritis, inflammatory bowel disease, vasculitis, and several types of cancer. The rapid production of IL-6 during infections and tissue damage aids in host defense. However, excessive synthesis of IL-6 and dysregulation of its receptor signaling (IL-6R) might contribute to the pathology of diseases. Recent advancements in clinical and basic research, along with developments in animal models, have established the significant role of IL-6 and its receptors in the pathogenesis of gout, although the precise mechanisms remain to be fully elucidated. This review discusses the role of IL-6 and its receptors in gout progression and examines contemporary research on modulating IL-6 and its signaling pathways for treatment. It aims to provide insights into the pathogenesis of gout and to advance the development of targeted therapies for gout-related inflammation.

The compelling role of allopurinol in hyperuricemia-induced epilepsy: Unrecognized like tears in rain

Epilepsy is a common neurological disease characterized by the recurrent, paroxysmal, and unprovoked seizures. It has been shown that hyperuricemia enhances and associated with the development and progression of epilepsy through induction of inflammation and oxidative stress. In addition, uric acid is released within the brain and contributes in the development of neuronal hyperexcitability and epileptic seizure. Brain uric acid acts as damage associated molecular pattern (DAMP) activates the immune response and induce the development of neuroinflammation. Therefore, inhibition of xanthine oxidase by allopurinol may reduce hyperuricemia-induced epileptic seizure and associated oxidative stress and inflammation. However, the underlying mechanism of allopurinol in the epilepsy was not fully elucidated. Therefore, this review aims to revise from published articles the link between hyperuricemia and epilepsy, and how allopurinol inhibits the development of epileptic seizure.

Arsenic Induced Oxidative Neural-Damages in Rat are Mitigated by Tea-Leave Extract via MMPs and AChE Inactivation, Shown by Molecular Docking and in Vitro Studies with Pure Theaflavin and AChE

BACKGROUND

Chronic arsenic-exposure causes neuromuscular disorders and other health anomalies. Damage to DNA and cytoskeletal/extracellular matrix is brought on by reactive-oxygen-species (ROS)-induced intrinsic antioxidant depletion (thiols/urate). Therapeutic chelating-agents have multiple side-effects.

OBJECTIVES

The protection of (Camellia sinensis) tea-extract and role of uric-acid (UA) or allopurinol (urate-depletor) on arsenic-toxicity were verified in rat model.

METHODS

Camellia sinensis (CS dry-leaves), UA or allopurinol was supplemented to arsenic-intoxicated rats for 4-weeks. Purified theaflavins and their galloyl-ester were tested in-vitro on pure AChE (acetylcholinesterase) and their PDB/PubChem 3-D structures were utilized for in-silico binding studies. The primary chemical components were evaluated from CS-extracts. Biochemical analysis, PAGE-zymogram, DNA-stability comet analysis, HE-staining was performed in arsenic-exposed rat brain tissues.

RESULTS

Animals exposed to arsenic showed symptoms of erratic locomotion, decreased intrinsic antioxidants (catalase/SOD1/uric acid), increased AChE, and malondialdehyde. Cerebellar and cerebrum tissue damages were shown with increased levels of matrix-metalloprotease (MMP2/9) and DNA damage (comets). Allopurinol- supplemented group demonstrated somewhat similar biochemical responses. In the CS-group brain tissues especially cerebellum is considerably protected which is evident from endogenous antioxidant and DNA and cytoskeleton protection with concomitant inactivation of MMPs and AChE. Present study indicates theaflavin-digallate (TFDG) demonstrated the highest inhibition of purified AChE (IC50 = 2.19 µg/ml with the lowest binding free-energy; -369.87 kcal/mol) followed by TFMG (IC50 = 3.86 µg/ml, -347.06 kcal/mol) suggesting their possible restoring effects of cholinergic response.

CONCLUSIONS

Favorable responses in UA-group and adverse outcome in allo-group justify the neuro-protective effects of UA as an endogenous antioxidant. Role of flavon-gallate in neuro protection mechanism may be further studied.

Pharmacological functions of salidroside in renal diseases: facts and perspectives

Rhodiola rosea is a valuable functional medicinal plant widely utilized in China and other Asian countries for its anti-fatigue, anti-aging, and altitude sickness prevention properties. Salidroside, a most active constituent derived from Rhodiola rosea, exhibits potent antioxidative, hypoxia-resistant, anti-inflammatory, anticancer, and anti-aging effects that have garnered significant attention. The appreciation of the pharmacological role of salidroside has burgeoned over the last decade, making it a beneficial option for the prevention and treatment of multiple diseases, including atherosclerosis, Alzheimer's disease, Parkinson's disease, cardiovascular disease, and more. With its anti-aging and renoprotective effects, in parallel with the inhibition of oxidative stress and inflammation, salidroside holds promise as a potential therapeutic agent for kidney damage. This article provides an overview of the microinflammatory state in kidney disease and discuss the current therapeutic strategies, with a particular focus on highlighting the recent advancements in utilizing salidroside for renal disease. The potential mechanisms of action of salidroside are primarily associated with the regulation of gene and protein expression in glomerular endothelial cells, podocytes, renal tubule cells, renal mesangial cells and renal cell carcinoma cell, including TNF-α, TGF-β, IL-1β, IL-17A, IL-6, MCP-1, Bcl-2, VEGF, ECM protein, caspase-3, HIF-1α, BIM, as well as the modulation of AMPK/SIRT1, Nrf2/HO-1, Sirt1/PGC-1α, ROS/Src/Cav-1, Akt/GSK-3β, TXNIP-NLRP3, ERK1/2, TGF-β1/Smad2/3, PI3K/Akt, Wnt1/Wnt3a β-catenin, TLR4/NF-κB, MAPK, JAK2/STAT3, SIRT1/Nrf2 pathways. To the best of our knowledge, this review is the first to comprehensively cover the protective effects of salidroside on diverse renal diseases, and suggests that salidroside has great potential to be developed as a drug for the prevention and treatment of metabolic syndrome, cardiovascular and cerebrovascular diseases and renal complications.

Role of EGF/ERK1/2/HO-1 axis in mediating methotrexate induced testicular damage in rats and the ameliorative effect of xanthine oxidase inhibitors

Objectives: Methotrexate (MTX) is commonly used in the management of several malignancies and autoimmune disorders; however, testicular damage is one of the most detrimental effects of MTX administration. The current the protective effect of xanthine oxidase inhibitors either purine analogue; allopurinol (ALL) or non-purine analogue; febuxostat (FEB) in testicular injury induced by MTX in rats.Materials and methods: Thirty-two rats were randomly allocated to four groups; control (received vehicles), MTX (received single dose, 20 mg/kg, i.p.), MTX + ALL (received MTX plus ALL) and MTX + FEB (received MTX plus ALL). ALL and FEB were administered orally at 100- and 10 mg/kg, respectively for 15 days. Total and free testosterone were measured in serum. In addition, total antioxidant capacity (TAC), epidermal growth factor (EGF), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), extracellular signal-regulating kinase1/2 (ERK1/2), and total nitrite/nitrate (NOx) end products were measured in testicular tissues. At the same time, immunoexpression of HO-1in testicular tissue was measured. Histopathological examination was done.Results: ALL and FEB increased total and free serum testosterone. Both drugs showed a significant reduction in testicular MDA, NOx, TNF-α levels with an increase in TAC, EGF, and ERK1/2 levels in testicular tissue. Furthermore, both drugs enhanced HO-1 immunoexpression in testicular tissue. All these findings were parallel to the preservation of normal testicular architecture in rats treated with ALL and FEB.Conclusion: All and FEB were equally protective against testicular damage induced by MTX through anti-inflammatory, anti-apoptotic, and antioxidant actions. Their effects might be through activation of the EGF/ERK1/2/HO-1 pathway.

Investigating the Anti-inflammatory Effect of Allopurinol on the Prevention of Prostate Cancer

Introduction Gout is a form of arthritis that arises from the accumulation of uric acid in the bloodstream. Allopurinol, a medication that reduces uric acid levels, has also been shown to have anti-inflammatory effects. Research in this area seems to have mixed results. Furthermore, limited research has examined the relationship between gout treated with Allopurinol and its possible protective factors against prostate cancer. The purpose of this study was to examine the relationship between Allopurinol use and prostate cancer, controlling for demographic and metabolic factors. Methods Information was collected from the National Health and Nutrition Examination Survey (NHANES) dataset of the Centers for Disease Control and Prevention (CDC). Logistic regression analysis was employed to establish the correlation between the usage of Allopurinol and the occurrence of prostate cancer while considering variables such as weight, hypertension, hyperlipidemia, race, educational level, and marital status. The research received approval from the review board of the Physician's Journal of Medicine. Results We found no significant association between Allopurinol use and prostate cancer, controlling for covariates. Age was found to have a positive association with prostate cancer. Marriage was found to have a negative association with prostate cancer. Conclusion The results of this study did not find a significant association between Allopurinol use and the risk of prostate cancer. However, this study adds to the limited body of research examining the relationship between gout, Allopurinol, and prostate cancer and suggests that further research is needed in this area. Overall, while Allopurinol has been shown to have anti-inflammatory effects and is used to treat gout, its use does not appear to have a significant impact on the risk of developing prostate cancer.

Oxypurinol protects renal ischemia/reperfusion injury via heme oxygenase-1 induction

Renal ischemia/reperfusion (I/R) injury is a major cause of acute kidney injury (AKI) by increasing oxidative stress, inflammatory responses, and tubular cell death. Oxypurinol, an active metabolite of allopurinol, is a potent anti-inflammatory and antioxidant agent. To investigate the therapeutic potential and underlying mechanism of oxypurinol in ischemic AKI, C57BL/6 male mice were intraperitoneally injected with oxypurinol and subjected to renal I/R or sham surgery. We found that oxypurinol-treated mice had lower plasma creatinine and blood urea nitrogen levels and tubular damage (hematoxylin-and-eosin staining) compared to vehicle-treated mice after renal I/R injury. Furthermore, oxypurinol treatment reduced kidney inflammation (i.e., neutrophil infiltration and MIP-2 mRNA induction), oxidative stress (i.e., 4-HNE, heme oxygenase-1 [HO-1], 8-OHdG expression, and Catalase mRNA induction), and apoptosis (i.e., TUNEL or cleaved caspase-3-positive renal tubular cells), compared to vehicle-treated mice. Mechanistically, oxypurinol induced protein expressions of HO-1, which is a critical cytoprotective enzyme during ischemic AKI, and oxypurinol-mediated protection against ischemic AKI was completely eliminated by pretreatment with tin protoporphyrin IX, an HO-1 inhibitor. In conclusion, oxypurinol protects against renal I/R injury by reducing oxidative stress, inflammation, and apoptosis via HO-1 induction, suggesting its preventive potential in ischemic AKI.

Mechanism Underlying the Action of Berberine in the Treatment of Gouty Arthritis Based on Network Pharmacology

Introduction: Gouty arthritis (GA) is induced by a purine metabolism disorder and monosodium urate (MSU) crystal-related inflammation. Berberine (BBR), extracted from Coptis chinensis, ameliorates MSU-induced GA. However, the mechanisms of BBR against GA remain to be fully elucidated. This study aimed to identify the key targets and pathways mediating the effects of BBR against GA using network pharmacology. Methods: BBR and GA targets were obtained from several databases, and the network of BBR-GA common targets was visualized using Cytoscape software. Protein–protein interaction (PPI), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed using the STRING and Database for Annotation, Visualization, and Integrated Discovery databases, respectively. Animal experiments were performed to determine the outcomes of the BBB intervention. The serum levels of IL-1β, IL-8, and IL-6 were detected using enzyme-linked immunosorbent assay. Results: Thirty-three common targets (including NF-κB, RelA, MAPK1, IL-6, and IL-1β) of BBR and GA were identified, and a network of common targets between BBR and GA was constructed. PPI analysis demonstrated that IL-1β, IL-6, TNF, MAPK, and RelA are key targets with high degree values. GO and KEGG pathway analyses revealed the involvement of inflammation-related biological processes and signaling pathways, such as the NF-κB, MAPK, and TNF signaling pathways. Animal experiments demonstrated that the uric acid, IL-1β, IL-6, and IL-8 serum levels were significantly lower in the BBR group compared with those in hyperuricemic rats. Conclusions: Using systematic network analysis, potential targets mediating the effects of BBR on GA were detected. The pathways and inflammatory factors involved were identified using in vivo experiments, thus providing a reference for further basic research and clinical applications of BBR in the treatment of GA.

Murine cytomegalovirus promotes renal allograft inflammation via Th1/17 cells and IL-17A

Human cytomegalovirus (HCMV) infection is associated with renal allograft failure. Allograft damage in animal models is accelerated by CMV-induced T helper 17 (Th17) cell infiltrates. However, the mechanisms whereby CMV promotes Th17 cell-mediated pathological organ inflammation are uncharacterized. Here we demonstrate that murine CMV (MCMV)-induced intragraft Th17 cells have a Th1/17 phenotype co-expressing IFN-γ and/or TNF-α, but only a minority of these cells are MCMV specific. Instead, MCMV promotes intragraft expression of CCL20 and CXCL10, which are associated with recruitment of CCR6⁺ CXCR3⁺ Th17 cells. MCMV also enhances Th17 cell infiltrates after ischemia-reperfusion injury, independent of allogeneic responses. Pharmacologic inhibition of the Th17 cell signature cytokine, IL-17A, ameliorates MCMV-associated allograft damage without increasing intragraft viral loads or reducing MCMV-specific Th1 cell infiltrates. Clinically, HCMV DNAemia is associated with higher serum IL-17A among renal transplant patients with acute rejection, linking HCMV reactivation with Th17 cell cytokine expression. In summary, CMV promotes allograft damage via cytokine-mediated Th1/17 cell recruitment, which may be pharmacologically targeted to mitigate graft injury while preserving antiviral T cell immunity.

The Prospective Effect of Allopurinol on the Oxidative Stress Index and Endothelial Dysfunction in Covid-19

SARS-CoV-2 by the direct cytopathic effect or indirectly through the propagation of pro-inflammatory cytokines could cause endothelial dysfunction (ED) and oxidative stress (OS). It has been reported that OS is triggered by various types of viral infections, including SARS-CoV-2. Into the bargain, allopurinol is regarded as a potent antioxidant that acts through inhibition of xanthine oxidase (XO), which is an essential enzyme of purine metabolism. Herein, the present study aimed to find the potential protective effects of allopurinol on the biomarkers of OS and ED in patients with severe Covid-19. This single-center cohort study recruited 39 patients with mild-moderate Covid-19 compared with 41 patients with severe Covid-19. Nineteen patients with severe Covid-19 were on the allopurinol treatment because of underlying chronic gout 3 years ago compared with 22 Covid-19 patients not on this treatment. The recruited patients were allocated into three groups: group I, mild-moderate Covid-19 on the standard therapy (n = 39); group II, severe Covid-19 patients on the standard therapy only (n = 22); and group III, severe Covid-19 patients on the standard therapy plus allopurinol (n = 19). The duration of the study was 3 weeks from the time of hospitalization till the time of recovery. In addition, inflammatory biomarkers (D-dimer, LDH, ferritin, CRP, procalcitonin), neutrophil-lymphocyte ratio (NLR), endothelin-1 (ET-1), uric acid and oxidative stress index (OSI), CT scan score, and clinical score were evaluated at the time of admission and discharge regarding the effect of allopurinol treatment adds to the standard treatment of Covid-19. Allopurinol plus standard treatment reduced LDH, ferritin, CRP, procalcitonin, and ET-1 serum level significantly (P < 0.05) compared with Covid-19 patients on standard treatment. Besides, neutrophil (%), lymphocyte (%), and neutrophil-lymphocyte ratio (NLR) were reduced in patients with severe Covid-19 on standard treatment plus allopurinol compared with Covid-19 patients on standard treatment alone (P < 0.01). OSI was higher in patients with severe Covid-19 than mild-moderate Covid-19 patients (P = 0.00001) at admission. At the time of discharge, the oxidative status of Covid-19 patients was significantly improved compared with that at admission (P = 0.01). In conclusion, Covid-19 severity is linked with high OS and inflammatory reaction with ED development. High uric acid in patients with severe Covid-19 is correlated with high OS and inflammatory biomarkers. Allopurinol with standard treatment in patients with severe Covid-19 reduced oxidative and inflammatory disorders with significant amelioration of ED and clinical outcomes.

The effect of trajectory of serum uric acid on survival and renal outcomes in patients with stage 3 chronic kidney disease

Uric acid (UA) is associated with renal disease and patient survival, but the causal associations remain unclear. Also, the longitudinal UA control (trajectory) is not well understood. We enrolled 808 subjects diagnosed with stage 3 chronic kidney disease from 2007 to 2017. We plotted the mean UA over a period of 6 months with a minimum requirement of 3 samples of UA. From the sampled points, we generated an interpolated line for each patient by joining mean values of UA levels over time. Using lines from all patients, we classified them into 3 groups of trajectories (low, medium, and high) through group-based trajectory modeling, and then we further separated them into either treatment or nontreatment subgroups. Due to multiple comparisons, we performed post hoc analysis by Bonferroni adjustment. Using univariate competing-risks regression, we calculated the competing risk analysis with subdistribution hazard ratio of possible confounders. All of the 6 trajectories appeared showed a gradual decline in function over time without any of the curves crossing over one another. For all-cause mortality risk, none of the variables (including age, gender, coronary arterial disease, cerebrovascular disease, diabetes mellitus, renin-angiotensin-aldosterone system inhibitors, trajectories of UA, and treatment of UA) were statistically significant. All 6 trajectories appeared as steady curves without crossovers among them over the entire period of follow-up. Patients with diabetes mellitus were statistically more likely to undergo dialysis. The only trend was seen in the on-treatment trajectories, which showed lower risks for dialysis compared to their nontreatment trajectories. There was no effect of UA control on survival. Initial treatment of UA is crucially important for UA control. However, the long-term effects on patients and renal survival appeared to be minor and without statistical significance.

Antagonist targeting miR‑106b‑5p attenuates acute renal injury by regulating renal function, apoptosis and autophagy via the upregulation of TCF4

Acute renal injury (ARI) is a life‑threatening condition and a main contributor to end‑stage renal disease, which is mainly caused by ischemia‑reperfusion (I/R). miR‑106b‑5p is a kidney function‑related miRNA; however, whether miR‑106b‑5p regulates the progression of ARI remains unclear. The present study thus aimed to examine the effects of miR‑106b‑5p antagonist on the regulation of ARI progression. It was found that miR‑106b‑5p expression was upregulated in the renal tissue of rats with I/R‑induced ARI and in NRK‑52E rat renal proximal tubular epithelial cells subjected to hypoxia‑reoxygenation (H/R). In vitro, H/R induction suppressed the proliferation, and promoted the apoptosis and autophagy of NRK‑52E cells, whereas miR‑106b‑5p antagonist (inhibition of miR‑106b‑5p) promoted the proliferation, and attenuated the apoptosis and autophagy of NRK‑52E cells under the H/R condition. Dual luciferase reporter gene assay validated that transcription factor 4 (TCF4) was a target of miR‑106b‑5p. It was further found that TCF4 overexpression promoted the proliferation, and inhibited the apoptosis and autophagy of NRK‑52E cells subjected to H/R. Moreover, the effects of miR‑106b‑5p antagonist on NRK‑52E cell proliferation, apoptosis and autophagy were mediated through the regulation of TCF4. In vivo, miR‑106b‑5p antagonist reduced the severity of renal injury, decreased cell proliferation in renal tissues and lowered the serum creatinine (Scr) and blood urea nitrogen (BUN) levels in the blood samples from rats with I/R‑induced ARI. On the whole, the findings presented herein demonstrate that miR‑106b‑5p antagonist attenuates ARI by promoting the proliferation, and suppressing the apoptosis and autophagy of renal cells via upregulating TCF4.

Dexmedetomidine Exerts Renal Protective Effect by Regulating the PGC-1α/STAT1/IRF-1 Axis

BACKGROUND

Ischemia-reperfusion (I/R) injury is the main cause of acute kidney injury (AKI), and its incidence and mortality increase year by year in the population. Dexmedetomidine (DEX) can improve AKI by regulating inflammation and oxidative stress, but its mechanism is still unclear.

METHODS

A hypoxia/reoxygenation (H/R) model of HK-2 cells and a kidney I/R model of C57BL/6J mice were established. In the experiment, cells were transfected with sh-PGC-1α to inhibit PGC-1α expression. The changes of ROS level and mitochondrial membrane potential (MMP) were analyzed. HE staining was used to assess kidney damage in mice. Concentration of kidney injury markers serum creatinine and blood urea nitrogen and expression of inflammatory factors were detected by ELISA. qPCR analysis was used to detect mRNA levels of related proteins in cells and mouse kidney tissues. The protein intracellular content and phosphorylation levels were determined by Western blotting.

RESULT

The production of inflammatory factors and ROS was increased in HK-2 cells treated with H/R, while MMP, cell viability, and mitochondrial-related protein levels were decreased. DEX attenuated pathological changes induced by H/R, while knockdown of PGC-1α eliminated the mitigation effect. DEX inhibited the damage of I/R to the kidneys of mice and increased the expression of mitochondrial-related proteins and PGC-1α in the kidneys, while inhibiting the phosphorylation of STAT1 and the expression of IRF-1.

CONCLUSIONS

DEX appears to inhibit mitochondrial damage and cellular inflammation by upregulating PGC-1α to affect STAT1 phosphorylation level and IRF-1 expression, thereby preventing AKI.

A Contrast Examination of Proinflammatory Effects on Kidney Function for γ-Fe2O3 NP and Gadolinium Dimeglumine

BACKGROUND

Contrast-enhanced magnetic resonance imaging (MRI) is a powerful diagnostic tool for many diseases. In many situations, the contrasts are repeatedly administrated in order to monitor and assess the disease progression.

OBJECTIVE

To investigate and compare the biological effects of γ-Fe2O3 nanoparticle (NP) and gadolinium dimeglumine (Gd-DTPA) with high and multiple doses on the kidney of healthy mice.

METHODS

Polydextrose sorbitol carboxymethyl ether coated γ-Fe2O3 NP with hydrodynamic size of 68.2 nm and clinically applied Gd-DTPA were employed on healthy mice with the repeatedly intravenous administration of high doses. The cell viability of human umbilical vein endothelial cells (HUVEC) in high doses of these two contrast agents were measured using the xCELLigence Real-Time Cell Analysis (RTCA) S16 Instrument. The biological effects of γ-Fe2O3 NP and Gd-DTPA on the kidney were obtained using a biochemical automatic analyzer and multiple proinflammatory factor kit on the serum. Histopathological and immunohistochemistry analysis were taken on kidney tissues.

RESULTS

It showed that the proinflammatory responses elicited by the γ-Fe2O3 NPs were weaker than that by Gd-DTPA, evidenced by the relatively much lower level of IL-1β, IL-6, IL-18, TNF-α, C-reactive protein (CRP) and Ferritin. At the same time, the γ-Fe2O3 NPs did not have the biochemical index elevated, while the Gd-DTPA did.

CONCLUSION

The γ-Fe2O3 NPs induced weaker proinflammatory effects in reference to the Gd-DTPA, indicating better renal safety. Therefore, it is suggested that γ-Fe2O3 NPs should be safer and optional choice when repeated contrast-enhanced MRI is necessary.

Xanthine oxidase inhibition in SARS-CoV-2 infection: the mechanism and potency of allopurinol and febuxostat in COVID-19 management

The number of coronavirus disease 2019 (COVID-19) infection cases has been increasing globally, including in Indonesia. Definitive therapy for COVID-19 has not yet been found; hence, repurposed drugs for COVID-19 have been considered and have been practiced by several researchers in the world. This literature review investigates the action of xanthine oxidase as a component of the biomolecular pathway against severe acute respiratory syndrome-related coronavirus-2, the cause of COVID-19, and describes the mechanism and potential of uric acid drugs (allopurinol and febuxostat) as prophylaxis and curative therapy for COVID-19. 

Role of Oxidative Stress in Hepatic and Extrahepatic Dysfunctions during Nonalcoholic Fatty Liver Disease (NAFLD)

Nonalcoholic fatty liver disease (NAFLD) is a pathology that contains a broad liver dysfunctions spectrum. These alterations span from noninflammatory isolated steatosis until nonalcoholic steatohepatitis (NASH), a more aggressive form of the disease characterized by steatosis, inflammatory status, and varying liver degrees fibrosis. NAFLD is the most prevalent chronic liver disease worldwide. The causes of NAFLD are diverse and include genetic and environmental factors. The presence of NASH is strongly associated with cirrhosis development and hepatocellular carcinoma, two conditions that require liver transplantation. The liver alterations during NAFLD are well described. Interestingly, this pathological condition also affects other critical tissues and organs, such as skeletal muscle and even the cardiovascular, renal, and nervous systems. Oxidative stress (OS) is a harmful state present in several chronic diseases, such as NAFLD. The purpose of this review is to describe hepatic and extrahepatic dysfunctions in NAFLD. We will also review the influence of OS on the physiopathological events that affect the critical function of the liver and peripheral tissues.

Anti-inflammatory and antioxidant activity of essential amino acid α-ketoacid analogues against renal ischemia-reperfusion damage in Wistar rats

Introduction:

Essential amino acid α-keto acid analogs are used in the treatment of chronic kidney disease to delay the symptoms of uremia. However, it is unknown whether essential amino acid α-keto acid analogs affect the oxidative stress and the inflammation in acute renal injury such as those produced by ischemia-reperfusion.

Objective:

To evaluate the effect of essential amino acid α-keto acid analogs on renal ischemia-reperfusion injury in Wistar rats.

Materials and methods:

Rats were divided into 11 groups (n=6/group): Two groups received physiological saline with or without ischemia-reperfusion injury (45 min/24 h), six groups received essential amino acid α-keto acid analogs (400, 800, or 1,200 mg/kg/24 h/7d) with or without ischemia-reperfusion injury (essential amino acid α-keto acid analogs + ischemia-reperfusion), and two groups received allopurinol (50 mg/kg/24 h/7d) with or without ischemia-reperfusion injury. Biochemical markers included creatinine and blood urea nitrogen (BUN), proinflammatory cytokines (IL-1β, IL-6, and TNF-α), renal damage markers (cystatin C, KIM-1, and NGAL), and markers of oxidative stress such as malondialdehyde (MDA) and total antioxidant activity.

Results:

The essential amino acid α-keto acid analog- and allopurinol-treated groups had lower levels of creatinine, BUN, renal damage markers, proinflammatory cytokines, and MDA than their corresponding ischemia-reperfusion groups. These changes were related to the essential amino acid α-keto acid analogs dosage. Total antioxidant activity was lower in essential amino acid α-keto acid analog- and allopurinol-treated groups than in the corresponding ischemia-reperfusion groups.

Conclusions:

This is a new report on the nephroprotective effects of essential amino acid α-keto acid analogs against ischemia-reperfusion injury. Essential amino acid α-keto acid analogs decreased the levels of biochemical markers, kidney injury markers, proinflammatory cytokines, and MDA while minimizing total antioxidant consumption.

Effect of infusion of M&G solution for protection of renal tissue in Wistar rats subjected to programmed ischemia-reperfusion

Background

Renal ischemia-reperfusion (I/R) is directly associated with acute renal failure and can occur in conditions such as infarction caused by embolization or thrombosis, septicemia, and kidney transplantation. The process is complex, involving innate and adaptive immune responses, presence of cellular infiltrate, and production and release of cytokines and chemokines. It also triggers cell responses and release of reactive oxygen species, in addition to causing apoptosis and, in some cases, cell necrosis. Against this background, evaluation of renal tissue protection mechanisms is essential.

Objectives

The objective of this study was to test the M&G solution, developed in prior research, evaluating its capacity to protect the kidneys using morphometric analysis and by assaying the presence and expression of inflammatory cytokines (TNF-alpha, VEGF, HIF, and IL-8).

Methods

Eighteen Wistar rats were divided into three groups: Sham (S), Control (C), and Experimental (E). The S group underwent the surgical operation, but without arterial clamping. In group C, the aorta was clamped above and below the left renal artery, without infusion of the preservation solution. In group E, in addition to clamping, the aorta was punctured and M&G solution was infused continuously for 20 minutes at 15^o C. Morphological analysis and immunohistochemical assessment of markers were then conducted.

Results

Morphological differences were identified in group S compared with groups C and E. Analysis of markers revealed reduced intensity of expression of TNF and of VEGF in group E. There were no differences in HIF or IL-8 between groups.

Conclusions

The M&G solution was associated with a reduction in presence and expression of TNF-alpha and a trend to reduced VEGF.

Role of JNK Signaling Pathway in Dexmedetomidine Post-Conditioning-Induced Reduction of the Inflammatory Response and Autophagy Effect of Focal Cerebral Ischemia Reperfusion Injury in Rats

To investigate the effect of dexmedetomidine post-conditioning on the inflammatory response and autophagy effect of focal cerebral ischemia reperfusion injury in rats, and further to study its potential mechanisms. Water maze was conducted to evaluate spatial learning and memory ability of middle cerebral artery occlusion (MCAO) rats. TTC staining was used to observe the area of cerebral infarction. The expressions of inflammatory factors in serum were detected by ELISA. TUNEL assay, HE staining, and transmission electron microscopy were used to detect the apoptosis of neurons, neuro-cytopathic changes, and the formation of auto-phagosome in hippocampus CA1 region, respectively. The mRNA and protein expression of Beclin-1, Caspase-3, and light chain 3 (LC3) were detected by qRT-PCR and Western blot. Moreover, the activity of C-Jun N-terminal kinase (JNK) pathway was detected by Western blot. The escape latency (EL); cerebral infarction area ratio; positive apoptosis; neuron pathological changes; auto-phagosome numbers; inflammatory factor contents; mRNA and protein expressions of Beclin-1, Caspase-3 and LC3II/I; and the phosphorylation level of JNK were decreased, while the times across platform and the times stayed in the quadrant of the original platform were increased after dexmedetomidine treatment. However, the protective effect of dexmedetomidine on brain injury in MCAO rats was reversed by JNK pathway activator. Dexmedetomidine post-conditioning could improve learning and memory dysfunction caused by MCAO in rats and reduce the inflammatory response and autophagy effect. The mechanism may be related to inhibition of JNK pathway activation.

The Protective Effect of A Short Peptide Derived From Cold-Inducible RNA-Binding Protein in Renal Ischemia-Reperfusion Injury

Extracellular cold-inducible RNA-binding protein (CIRP) functions as damage-associated molecular pattern and has been demonstrated to be responsible in part for the damage occurring after renal ischemia-reperfusion (I/R). A short peptide derived from CIRP, named C23, binds to myeloid differentiation factor 2, a Toll-like receptor 4 coreceptor. We hypothesize that C23 reduces renal ischemia-reperfusion (RIR) injury by blocking CIRP. We observed that pretreatment with C23 significantly decreased the levels of recombinant mouse CIRP-induced tumor necrosis factor-α (TNF-α) in a dose-dependent fashion in cultured macrophages. C57BL/6 mice were subjected to bilateral renal pedicle clamps for 35 min to induce ischemia, followed by reperfusion for 24 h and harvest of blood and renal tissue. C23 peptide (8 mg/kg) or vehicle was injected intraperitoneally at the beginning of reperfusion. Plasma TNF-α, interleukin 1 beta (IL-1β), and IL-6 levels were decreased in C23-treated RIR mice as compared with vehicle-treated mice by 74%, 85%, and 68%, respectively. Expressions of TNF-α and keratinocyte chemoattractant in the kidneys from C23-treated mice were decreased by 55% and 60%, respectively. Expression of kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin in the kidney of C23-treated mice were significantly reduced by 46% and 55%, respectively. Renal tissue histological assessments revealed significant reduction in damage score by 44% in C23-treated mice. Finally, a survival study revealed a significant survival advantage with a 70% survival rate in C23 group vs. 37% in vehicle group. Thus, C23 has potential as a novel therapy for the patients suffering from I/R-induced renal injury.

Porous Se@SiO2 nanospheres attenuate ischemia/reperfusion (I/R)-induced acute kidney injury (AKI) and inflammation by antioxidative stress

Objectives

Acute kidney injury (AKI) is a growing global health concern, and is associated with high rates of mortality and morbidity in intensive care units. Se is a trace element with antioxidant properties. This study aimed to determine whether porous Se@SiO₂ nanospheres could relieve oxidative stress and inflammation in ischemia/reperfusion (I/R)-induced AKI.

Methods

Male 6- to 8-week-old C57bl/6 mice were divided into four groups: sham + saline, sham + Se@SiO₂, I/R + saline, and I/R + Se@SiO₂. Mice in the I/R groups experienced 30 minutes of bilateral renal I/R to induce an AKI. Porous Se@SiO₂ nanospheres (1 mg/kg) were intraperitoneally injected into mice in the I/R + Se@SiO₂ group 2 hours before I/R, and the same dose was injected every 12 hours thereafter. Hypoxia/reoxygenation (H/R) was used to mimic I/R in vitro. PBS was used as a control treatment. Human kidney 2 cells were seeded into 12-well plates (5×10⁵ cells/well) and divided into four groups: control + PBS group, control + Se@SiO₂ group, H/R + PBS group, and H/R + Se@SiO₂ group (n=3 wells). We then determined the expression levels of ROS, glutathione, inflammatory cytokines and proteins, fibrosis proteins, and carried out histological analysis upon kidney tissues.

Results

In vitro, intervention with porous Se@SiO₂ nanospheres significantly reduced levels of ROS (P<0.05), inflammatory cytokines (P<0.05), and inflammation-associated proteins (P<0.05). In vivo, tubular damage, cell apoptosis, and interstitial inflammation during AKI were reduced significantly following treatment with porous Se@SiO₂ nanospheres. Moreover, the occurrence of fibrosis and tubular atrophy after AKI was attenuated by porous Se@SiO₂ nanospheres.

Conclusion

Porous Se@SiO₂ nanospheres exhibited a protective effect in I/R-induced AKI by resisting oxidative stress and inflammation. This suggests that porous Se@SiO₂ nanospheres may represent a new therapeutic method for AKI.

Beneficial effects of inhaled nitric oxide with intravenous steroid in an ischemia-reperfusion model involving aortic clamping

This study evaluated the effects of inhaled nitric oxide (iNO) therapy combined with intravenous (IV) corticosteroids on hemodynamics, selected cytokines, and kidney messenger RNA toll-like receptor 4 (mRNA TLR4) expression in ischemia–reperfusion injury animal model. The primary endpoint was the evaluation of circulatory, respiratory, and renal function over time. We also investigated the profile of selected cytokines and high-mobility group box 1 (HMGB1) protein, as well as renal mRNA TLR4 activation determined by quantitative real-time polymerase chain reaction analysis. Pigs (n = 19) under sevoflurane AnaConDa anesthesia/sedation were randomized and subjected to abdominal laparotomy and alternatively suprarenal aortic cross-clamping (SRACC) for 90 min or sham surgery: Group 1 (n = 8) iNO (80 ppm) + IV corticosteroids (25 mg ×3) started 30 min before SRACC and continued 2 h after SRACC release, followed with decreased iNO (30 ppm) until the end of observation, Group 2 (n = 8) 90 min SRACC, Group 3 (n = 3)—sham surgery. Renal biopsies were sampled 1 hr before SRACC and at 3 and 20 h after SRACC release. Aortic clamping increased TLR4 mRNA expression in ischemic kidneys, but significant changes were recorded only in the control group (P = 0.016). Treatment with iNO and hydrocortisone reduced TLR4 mRNA expression to pre-ischemic conditions, and the difference observed in mRNA expression was significant between control and treatment group after 3 h (P = 0.042). Moreover, animals subjected to treatment with iNO and hydrocortisone displayed an attenuated systemic inflammatory response and lowered pulmonary vascular resistance plus increased oxygen delivery. The results indicated that iNO therapy combined with IV corticosteroids improved central and systemic hemodynamics, oxygen delivery, and diminished the systemic inflammatory response and renal mRNA TLR4 expression.

IL-35 is a Protective Immunomodulator in Brain Ischemic Injury in Mice

IL-35 has been identified as a novel anti-inflammatory cytokine that belongs to the IL-12 cytokine family and has been verified to play a protective role in autoimmune diseases. In this study, we investigated the protective effects of IL-35 on cerebral ischemia/reperfusion (I/R) injury in a middle cerebral artery occlusion mouse model. We determined that the expression of IL-35 was initially decreased and subsequently increased in I/R injury. Moreover, IL-35 (i.c.v.) pre- and posttreatment significantly reduced the infarct volume and improved neurological deficits after 45 min of ischemia and 24 h of reperfusion. Importantly, IL-35 treatment improved neurological function recovery, particularly in balance ability, at 14 days after treatment. Finally, our results showed that IL-35 treatment reduced the expression of IL-6 and IL-1β, which are confirmed proinflammatory cytokines, thus indicating that these cytokines have both been linked to the anti-inflammatory mechanisms of IL-35. Therefore, IL-35 may be a key immune mediator in brain ischemic injury and appears to have promising potential for clinical trials.

Protective Role for Antioxidants in Acute Kidney Disease

Acute kidney injury causes significant morbidity and mortality in the community and clinic. Various pathologies, including renal and cardiovascular disease, traumatic injury/rhabdomyolysis, sepsis, and nephrotoxicity, that cause acute kidney injury (AKI), induce general or regional decreases in renal blood flow. The ensuing renal hypoxia and ischemia promotes the formation of reactive oxygen species (ROS) such as superoxide radical anions, peroxides, and hydroxyl radicals, that can oxidatively damage biomolecules and membranes, and affect organelle function and induce renal tubule cell injury, inflammation, and vascular dysfunction. Acute kidney injury is associated with increased oxidative damage, and various endogenous and synthetic antioxidants that mitigate source and derived oxidants are beneficial in cell-based and animal studies. However, the benefit of synthetic antioxidant supplementation in human acute kidney injury and renal disease remains to be realized. The endogenous low-molecular weight, non-proteinaceous antioxidant, ascorbate (vitamin C), is a promising therapeutic in human renal injury in critical illness and nephrotoxicity. Ascorbate may exert significant protection by reducing reactive oxygen species and renal oxidative damage via its antioxidant activity, and/or by its non-antioxidant functions in maintaining hydroxylase and monooxygenase enzymes, and endothelium and vascular function. Ascorbate supplementation may be particularly important in renal injury patients with low vitamin C status.