Resveratrol attenuates lipopolysaccharide-induced acute kidney injury by suppressing inflammation driven by macrophages

Nanoparticles constructed from natural polyphenols are used in acute kidney injury

Acute kidney injury (AKI) is a severe clinical syndrome characterized by rapid deterioration of renal function caused by a variety of pathogeneses. Natural polyphenols have been considered to have potential in the treatment of AKI due to their powerful antioxidant and anti-inflammatory activities, but their low bioavailability in vivo limits their efficacy. Polyphenol nanoparticles based on a nano-delivery system show good effects in reducing kidney injury, improving renal function and promoting renal tissue repair, and brings new hope and possibility for the treatment of AKI. This review provides an overview of the common characteristics, treatments, and associated adverse effects of AKI. The classification and bioavailability of polyphenols as well as their therapeutic role in AKI and potential possible effects are outlined. The potential therapeutic effects of polyphenol-based nanoparticles on AKI and the underlying mechanisms are discussed.

The Protecting Role of Black Seed Oil and Its Nano-Formulation in LPS-Induced Acute Kidney Injury in Mice: Evaluation of Oxidative Stress, Biochemical & Molecular Parameters

Background

Acute kidney injury (AKI) is a medical concern that is accompanied by the rapid deterioration of kidney function. It can be triggered by lipopolysaccharide (LPS) of gram-negative bacteria as it activates a complicated immune response, resulting in widespread inflammation and potential organ dysfunction. Black seed oil (BSO) is rich in beneficial constituents and has been widely used owing to its nutritional advantages.

Purpose

This research is aimed to investigate the potential protective effects of BSO and its nano-formulation on AKI induced by LPS. It also aimed to compare their anti-inflammatory activity with indomethacin, a known synthetic anti-inflammatory drug.

Materials and Methods

Forty-eight mice were placed randomly into 8 groups. A single intraperitoneal (i.p.) injection of 2.5 mg/kg B.W. of LPS was used to trigger inflammation, and pretreatment with BSO and its nano-formulation was at 0.2 mL/kg/day for 14 consecutive days. Indomethacin was used as a reference drug and its efficacy was tested alone or in combination with BSO at lower doses. Renal function was assessed using urea, creatinine, neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1). Also, oxidative and inflammatory markers were assessed by measuring levels of reduced glutathione (GSH), nitric oxide (NO), cyclooxygenase-2 (COX-2), tumor necrosis factor alpha (TNF-α), and toll-like receptor-4 (TLR-4). Histopathological examination of the kidney tissues was also performed.

Results

The study showed that BSO and its nano-formulation had anti-inflammatory effects comparable to or better than those of indomethacin. They greatly decreased the oxidative stress and inflammatory markers induced by LPS. Their protective effect against pathological alterations in kidney tissues was significantly noticed.

Conclusion

BSO and its nano-formulation could be used as nephroprotective and anti-inflammatory supplements.

The Mechanism of Hyperoxia-Induced Neonatal Renal Injury and the Possible Protective Effect of Resveratrol

With recent advances in neonatal intensive care, preterm infants are surviving into adulthood. Nonetheless, epidemiological data on the health status of these preterm infants have begun to reveal a worrying theme; prematurity and the supplemental oxygen therapy these infants receive after birth appear to be risk factors for kidney disease in adulthood, affecting their quality of life. As the incidence of chronic kidney disease and the survival time of preterm infants both increase, the management of the hyperoxia-induced renal disease is becoming increasingly relevant to neonatologists. The mechanism of this increased risk is currently unknown, but prematurity itself and hyperoxia exposure after birth may predispose to disease by altering the normal trajectory of kidney maturation. This article reviews altered renal reactivity due to hyperoxia, the possible mechanisms of renal injury due to hyperoxia, and the role of resveratrol in renal injury. KEY POINTS: · Premature infants commonly receive supplementary oxygen.. · Hyperoxia can cause kidney damage via signal pathways.. · We should reduce the occurrence of late sequelae..

Analysis of cantharidin-induced kidney injury and the protective mechanism of resveratrol in mice determined by liquid chromatography/mass spectrometry-based metabonomics

Cantharidin (CTD) is the main active component in the traditional Chinese medicine Mylabris and an effective anti-tumor agent. However, it is relatively toxic and exhibits nephrotoxicity, which limits its clinical use. However, its toxic mechanism is not clear. The toxic effects of CTD exposure on the kidney and the protective effect of resveratrol (RES) were studied in a mouse model, by determination of serum biochemical and renal antioxidant indicators, histopathological and ultrastructural observation, and metabonomics. After CTD exposure, serum uric acid, creatinine, and tissue oxidative stress indicators increased, and the renal glomerular and tubular epithelial cells showed clear pathological damage. Ultrastructure observation revealed marked mitochondrial swelling, endoplasmic reticulum dilation, and the presence of autophagy lysosomes in glomerular epithelial cells. RES ameliorated the renal injury induced by CTD. Metabonomics analysis indicated that CTD can induce apoptosis and oxidative damage in kidney cells, mainly by disrupting sphingolipid and glutathione metabolism, increasing sphingosine and sphingomyelin levels, and decreasing glutathione levels. RES counteracts these effects by regulating renal cell proliferation, the inflammatory response, oxidative stress, and apoptosis, by improving the levels of phosphatidylcholine (PC), LysoPC, and lysophosphatidyl glycerol in the glycerophospholipid metabolism pathway, thereby reducing CTD-induced nephrotoxicity. The mechanisms of CTD-induced renal injury and the protective effect of RES were revealed by metabonomics, providing a basis for evaluating clinical treatment regimens to reduce CTD-induced nephrotoxicity.

Traditional Chinese Medicine and renal regeneration: experimental evidence and future perspectives

Repair of acute kidney injury (AKI) is a typical example of renal regeneration. AKI is characterized by tubular cell death, peritubular capillary (PTC) thinning, and immune system activation. After renal tubule injury, resident renal progenitor cells, or renal tubule dedifferentiation, give rise to renal progenitor cells and repair the damaged renal tubule through proliferation and differentiation. Mesenchymal stem cells (MSCs) also play an important role in renal tubular repair. AKI leads to sparse PTC, affecting the supply of nutrients and oxygen and indirectly aggravating AKI. Therefore, repairing PTC is important for the prognosis of AKI. The activation of the immune system is conducive for the body to clear the necrotic cells and debris generated by AKI; however, if the immune activation is too strong or lengthy, it will cause damage to renal tubule cells or inhibit their repair. Macrophages have been shown to play an important role in the repair of kidney injury. Traditional Chinese medicine (TCM) has unique advantages in the treatment of AKI and a series of studies have been conducted on the topic in recent years. Herein, the role of TCM in promoting the repair of renal injury and its molecular mechanism is discussed from three perspectives: repair of renal tubular epithelial cells, repair of PTC, and regulation of macrophages to provide a reference for the treatment and mechanistic research of AKI.

Resveratrol Inhibits circ_0074371-related Pathway to Alleviate Sepsis-induced Acute Kidney Injury

Resveratrol has a protective effect on sepsis-induced acute kidney injury (AKI). Circ_0074371 has been confirmed to inhibit sepsis-induced AKI process, but whether resveratrol inhibits sepsis-induced AKI by regulating circ_0074371-related pathway remains unclear. In this study, lipopolysaccharide (LPS)-induced renal tubular epithelial cells (HK2) were used to mimic AKI cell models. Quantitative real-time PCR was used to detect relative expression of circ_0074371, microRNA (miR)-145-5p and inositol polyphosphate multikinase (IPMK). Cell proliferation and apoptosis were detected by cell counting kit 8 assay, EdU assay and flow cytometry. The levels of inflammation factors were measured by ELISA assay, and MDA level and SOD activity were examined to assess oxidative stress. Protein expression of IPMK was evaluated by western bolt analysis. The relationship between miR-145-5p and circ_0074371 or IPMK was confirmed by dual-luciferase reporter assay. It was showed that circ_0074371 was upregulated in AKI patients and LPS-induced HK2 cells, and silencing of circ_0074371 promoted proliferation and inhibited apoptosis, inflammation and oxidative stress in LPS-induced HK2 cells. In terms of mechanism, circ_0074371 sponged miR-145-5p to positively regulate IPMK. IPMK overexpression could reverse the relieving effect of circ_0074371 knockdown on LPS-induced HK2 cell injury. Moreover, resveratrol suppressed LPS-induced apoptosis, inflammation and oxidative stress in HK2 cells, and circ_0074371 overexpression also reversed the protective effect of resveratrol against LPS-induced cell injury. Our data suggested that resveratrol alleviated LPS-induced HK2 cell injury by inactivating the circ_0074371/miR-145-5p/IPMK axis.

Network pharmacology and experimental validation to investigate the mechanism of Nao-Ling-Su capsule in the treatment of ischemia/reperfusion-induced acute kidney injury

ETHNOPHARMACOLOGICAL RELEVANCE

Nao-Ling-Su Capsule (NLSC) is a traditional prescription, which is composed of fifteen herbs such as epimedium, Polygala tenuifolia, and Schisandra chinensis. It has the effect of strengthening the brain, calming nerves, and protecting the kidney, which has been used clinically for many years to strengthen the brain and kidney. However, the effect of NLSC in the treatment of acute kidney injury (AKI) is still unclear.

AIM OF THE STUDY

The present study aims to elucidate the pharmacological actions of NLSC in the treatment of AKI.

MATERIALS AND METHODS

Molecular targets for NLSC and AKI were obtained from various databases, and then we built networks of interactions between proteins (PPI) by employing string databases. Additionally, we employed the DAVID database to conduct gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Molecular docking was conducted to analyze the interaction between core components and their corresponding core targets. Next, the C57BL male mice model of ischemia/reperfusion damage (IRI) was developed, and the nephridial protective effect of NLSC was evaluated. The accuracy of the expected targets was confirmed using real-time quantitative polymerase chain reaction (RT-qPCR). The renal protective effect of NLSC was assessed using an immortalized human kidney tubular (HK-2) cell culture produced by oxygen-glucose deprivation (OGD).

RESULTS

Network pharmacology analysis identified 199 common targets from NLSC and AKI. STAT3, HSP90AA1, TP53, MAPK3, JUN, JAK2, and VEGFA could serve as potential drug targets and were associated with JAK2/STAT3 signaling pathway, PI3K-Akt signaling pathway, etc. The molecular docking analysis confirmed significant docking activity between the main bioactive components and core targets, including STAT3 and KIM-1. Moreover, the AKI mice model was successfully established and NLSC pretreatment could improve renal function and alleviate renal damage. NLSC could alleviate renal inflammation and tubular cell apoptosis, and decrease the expression of STAT3 and KIM-1 in AKI mice. In vitro, both NLSC and drug-containing serum may protect HK-2 cells by inhibiting STAT3 signaling, especially STAT3-mediated apoptosis and KIM-1 expression.

CONCLUSION

NLSC could alleviate renal inflammation and apoptosis, exerting its beneficial effects by targeting the STAT3/KIM-1 pathway. NLSC is a promising candidate for AKI treatment and provides a new idea and method for the treatment of AKI.

Effect of polyphenols against complications of COVID-19: current evidence and potential efficacy

The COVID-19 pandemic that started in 2019 and resulted in significant morbidity and mortality continues to be a significant global health challenge, characterized by inflammation, oxidative stress, and immune system dysfunction.. Developing therapies for preventing or treating COVID-19 remains an important goal for pharmacology and drug development research. Polyphenols are effective against various viral infections and can be extracted and isolated from plants without losing their therapeutic potential. Researchers have developed methods for separating and isolating polyphenols from complex matrices. Polyphenols are effective in treating common viral infections, including COVID-19, and can also boost immunity. Polyphenolic-based antiviral medications can mitigate SARS-CoV-2 enzymes vital to virus replication and infection. Individual polyphenolic triterpenoids, flavonoids, anthraquinonoids, and tannins may also inhibit the SARS-CoV-2 protease. Polyphenol pharmacophore structures identified to date can explain their action and lead to the design of novel anti-COVID-19 compounds. Polyphenol-containing mixtures offer the advantages of a well-recognized safety profile with few known severe side effects. However, studies to date are limited, and further animal studies and randomized controlled trials are needed in future studies. The purpose of this study was to review and present the latest findings on the therapeutic impact of plant-derived polyphenols on COVID-19 infection and its complications. Exploring alternative approaches to traditional therapies could aid in developing novel drugs and remedies against coronavirus infection.

A short treatment with resveratrol after a renal ischaemia-reperfusion injury prevents maladaptive repair and long-term chronic kidney disease in rats

Acute kidney injury (AKI) often triggers physiological processes aimed at restoring renal function and architecture. However, this response can become maladaptive, leading to nephron loss and fibrosis. Although the therapeutic effects of resveratrol (RSV) are well established, its impact after AKI and for subsequent chronic kidney disease (CKD) remains unclear. This study assessed whether transient administration of RSV following ischaemia-reperfusion injury (IRI) could prevent the progression to CKD. Forty-one male Wistar rats were assigned randomly to sham surgery, bilateral renal ischaemia for 30 min (IR) or IR+RSV. The RSV treatment commenced 24 h after IRI and continued for 10 days. The rats were studied for either 10 days or 5 months, after which kidney function and structure were evaluated. Mitochondrial homeostasis, oxidant defence and renal inflammation state were also evaluated. Despite having the same severity of AKI, rats receiving RSV for 10 days after IRI exhibited significant improvement in kidney histological injury and reduced inflammation, although renal haemodynamic recovery was less pronounced. Resveratrol effectively prevented the elevation of tubular injury-related molecules and profibrotic signalling with reduced myofibroblast proliferation. Furthermore, RSV substantially improved the antioxidant response and mitochondrial homeostasis. After 5 months, RSV prevented the transition to CKD, as evidenced by the prevention of progressive proteinuria, renal dysfunction and tubulointerstitial fibrosis. This study demonstrates that a brief treatment with RSV following IRI is enough to prevent maladaptive repair and the development of CKD. Our findings highlight the importance of the early days of reperfusion, indicating that maladaptive responses can be reduced effectively following severe AKI. KEY POINTS: Physiological processes activated after acute kidney injury (AKI) can lead to maladaptive responses, causing nephron loss and fibrosis. Prophylactic renoprotection with resveratrol (RSV) has been described in experimental AKI, but its impact after AKI and for subsequent chronic kidney disease (CKD) remains unclear. In this study, we found that histological tubular injury persists 10 days after ischaemia-reperfusion injury and contributes to a failed repair phenotype in proximal tubular cells. Short-term RSV intervention influenced the post-ischaemic repair response and accelerated tubular recovery by reducing oxidative stress and mitochondrial damage. Furthermore, RSV targeted inflammation and profibrotic signalling during the maladaptive response, normalizing both processes. Resveratrol effectively prevented AKI-to-CKD transition even 5 months after the intervention. The study serves as a proof of concept, proposing RSV as a valuable candidate for further translational clinical studies to mitigate AKI-to-CKD transition.

Effects and mechanisms of frehmaglutin D and rehmaionoside C improve LPS-induced acute kidney injury through the estrogen receptor-mediated TLR4 pathway in vivo and in vitro

BACKGROUND

Sepsis-induced acute kidney injury (S-AKI) is an inflammatory disease with sex differences and there has no effective drugs to cure it. Frehmaglutin D (Fre D) and rehmaionoside C (Reh C) are two violetone compounds with estrogenic activity isolated from Rehmannia glutinosa. However, whether these two drugs exert protective effects on S-AKI through their estrogen-like activity are unclear.

PURPOSE

This study aimed to explore the effects and mechanisms of Fre D and Reh C on lipopolysaccharide (LPS)-induced S-AKI through the estrogen receptor pathway in vivo and in vitro and to explore the interaction between ER and TLR4 for the first time.

METHODS

The LPS-induced female BALB/c mice S-AKI mouse model was established by adding the estrogen receptor antagonist ICI182,780. Renal function, inflammation, oxidative stress, apoptosis, immune cells, and expression of key proteins of the ER-TLR4-IL-1β pathway were tested. The affinity of Fre D and Reh C for the ER was investigated by molecular docking. Then, an in vitro S-AKI model was established, and ERα/ERβ antagonists (MPP/PHTPP) were added and combined with gene overexpression techniques. The interaction between ER and TLR4 was further explored by Co-IP, GST pull-down and SPR techniques.

RESULTS

Fre D and Reh C ameliorated LPS-induced renal damage, inflammation in mice, regulated the immune cells, decreased ROS levels, increased ERα and ERβ protein expression, and decreased TLR4, caspase 11 and IL-1β protein expression. These effects were blocked by ICI182,780. Molecular docking results showed that Fre D and Reh C bound ERα and ERβ with similar potency. The results of in vitro suggested that Fre D and Reh C reduced the levels of inflammation, ROS and apoptosis, TLR4, caspase 11, and IL-1β protein expression and increased ERα/ERβ protein expression in cells. All of these effects were reversed by the addition of MPP/PHTPP and further enhanced after ERα/ERβ gene overexpression with no significant difference in effects. Moreover, there was an indirect or direct interaction between ER and TLR4, and the binding of ERα and ERβ to TLR4 was concentration dependent.

CONCLUSION

Fre D and Reh C may improve S-AKI through the ER-TLR4-IL-1β pathway and may act on both ERα and ERβ receptors. Moreover, ERα and ERβ may interact directly or indirectly with TLR4, which was studied for the first time.

Acute Kidney Injury: Definition, Management, and Promising Therapeutic Target

Acute kidney injury (AKI) is caused by a sudden loss of renal function, resulting in the build-up of waste products and a significant increase in mortality and morbidity. It is commonly diagnosed in critically ill patients, with its occurrence estimated at up to 50% in patients hospitalized in the intensive critical unit. Despite ongoing efforts, the death rate associated with AKI has remained high over the past half-century. Thus, it is critical to investigate novel therapy options for preventing the epidemic. Many studies have found that inflammation and Toll-like receptor-4 (TLR-4) activation have a significant role in the pathogenesis of AKI. Noteworthy, challenges in the search for efficient pharmacological therapy for AKI have arisen due to the multifaceted origin and complexity of the clinical history of people with the disease. This article focuses on kidney injury's epidemiology, risk factors, and pathophysiological processes. Specifically, it focuses on the role of TLRs especially type 4 in disease development.

Macrophage angiotensin AT2 receptor activation is protective against early phases of LPS-induced acute kidney injury

Lipopolysaccharide (LPS)-induced acute kidney injury (AKI) is characterized by inflammation and infiltration of immune cells, mainly neutrophils and macrophages, and results in sudden renal dysfunction. Previously, we have reported the anti-inflammatory and renoprotective role of the angiotensin II type 2 receptor (AT2R), expressed on kidney tubular cells and immune cells, in LPS-induced AKI. Moreover, in vitro studies revealed macrophage AT2R activation shifts the cells to the anti-inflammatory M2 subtype. However, the protective role of the macrophage AT2R in a model of AKI is unknown. The present study addressed this question by adoptive transfer of bone marrow-derived macrophages (BMDMs) in systemic macrophage-depleted mice. We acquired significant systemic macrophage depletion by two doses of liposomal clodronate (CLD), and the mice were repopulated with BMDMs (CD11b+F4/80+, double positive) primed with AT2R agonist C21 (CLD + MacC21 + LPS) or vehicle (CLD + Mac + LPS) in vitro for 60 min, followed by LPS (5 mg/kg body wt ip) challenge. We observed a gradual increase in the CD11b+ cells at 2 and 24 h after the LPS challenge. However, kidney CD11b+ cells in the CLD + Mac + LPS group were elevated compared with the CLD + MacC21 + LPS group at 2 h after the LPS challenge. The level of inflammatory cytokine (tumor necrosis factor-α) was elevated at 2 h, which was reduced significantly in CLD + MacC21 + LPS-treated animals. Also, CLD + MacC21 + LPS-treated animals had elevated plasma and renal IL-10, indicating an anti-inflammatory role of C21-treated BMDMs. Renal functional injury in CLD + MacC21 + LPS-treated animals was partially improved. Collectively, the data demonstrate that BMDM AT2R stimulation results in anti-inflammation and partial renoprotection against early stages of LPS-induced AKI.NEW & NOTEWORTHY Endotoxin such as lipopolysaccharide (LPS) induces acute kidney injury (AKI), which is a risk factor for and often leads to chronic kidney diseases. The present study revealed that bone marrow-derived macrophage activation of the angiotensin II type 2 receptor (AT2R) contributes to the anti-inflammation and partial renoprotection against early stages of LPS-induced AKI. Since AT2R is an emerging anti-inflammatory and organ-protective target, this study advances our understanding of AT2R's anti-inflammatory mechanisms associated with renoprotection.

Deubiquitinase BAP1 regulates stability of BRCA1 protein and inactivates the NF-κB signaling to protect mice from sepsis-induced acute kidney injury

Sepsis and its associated organ dysfunction syndrome is a leading cause of death in critically ill patients. Breast cancer susceptibility protein 1 (BRCA1)-associated protein 1 (BAP1) is a potential regulator in immune regulation and inflammatory responses. This study aims to investigate the function of BAP1 in sepsis-induced acute kidney injury (AKI). A mouse model with sepsis-induced AKI was induced by cecal ligation and puncture, and renal tubular epithelial cells (RTECs) were treated with lipopolysaccharide (LPS) to mimic an AKI condition in vitro. BAP1 was significantly poorly expressed in the kidney tissues of model mice and the LPS-treated RTECs. Artificial upregulation of BAP1 ameliorated the pathological changes, tissue injury and inflammatory responses in kidney tissues of the mice, and it reduced the LPS-induced injury and apoptosis of the RTECs. BAP1 was found to interact with BRCA1 and enhance stability of BRCA1 protein through deubiquitination modification. Further downregulation of BRCA1 activated the nuclear factor-kappa B (NF-κB) signaling pathway and blocked the protective roles of BAP1 in sepsis-induced AKI. In conclusion, this study demonstrates that BAP1 protects mice from sepsis-induced AKI through enhancing stability of BRCA1 protein and inactivating the NF-κB signaling.

A comprehensive insight into the molecular and cellular mechanisms of action of resveratrol on complications of sepsis a systematic review

Sepsis and septic shock are still one of the most important medical challenges. Sepsis is an extreme and uncontrolled response of the innate immune system to invading pathogenesis. Resveratrol (3,5,4'-trihydroxytrans-stilbene), is a phenolic and non-flavonoid compound naturally produced by some plants and fruits. The object of the current study is to systematically review the impacts of resveratrol and its mechanisms of function in the management of sepsis and its related complications. The guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statements were applied to perform the study (PROSPERO: CRD42021289357). We searched Embase, Web of Science, Google Scholar, Science Direct, PubMed, ProQuest, and Scopus databases up to January 2023 by using the relevant keywords. Study criteria were met by 72 out of 1415 articles screened. The results of this systematic review depict that resveratrol can reduces the complications of sepsis by affecting inflammatory pathways, oxidative stress, and modulating immune responses. Future human randomized clinical trials are necessary due to the promising therapeutic effects of resveratrol on sepsis complications and the lack of clinical trials in this regard.

Casein Kinase 2 Alpha Inhibition Protects against Sepsis-Induced Acute Kidney Injury

Sepsis-induced acute kidney injury (AKI) is a common complication in critically ill patients, often resulting in high rates of morbidity and mortality. Previous studies have demonstrated the effectiveness of casein kinase 2 alpha (CK2α) inhibition in ameliorating ischemia-reperfusion-induced AKI. In this study, our aim was to investigate the potential of the selective CK2α inhibitor, 4,5,6,7-tetrabromobenzotriazole (TBBt), in the context of sepsis-induced AKI. To assess this, we initially confirmed an upregulation of CK2α expression following a cecum ligation and puncture (CLP) procedure in mice. Subsequently, TBBt was administered to a group of mice prior to CLP, and their outcomes were compared to those of sham mice. The results revealed that, following CLP, the mice exhibited typical sepsis-associated patterns of AKI, characterized by reduced renal function (evidenced by elevated blood urea nitrogen and creatinine levels), renal damage, and inflammation (indicated by increased tubular injury score, pro-inflammatory cytokine levels, and apoptosis index). However, mice treated with TBBt demonstrated fewer of these changes, and their renal function and architecture remained comparable to that of the sham mice. The anti-inflammatory and anti-apoptotic properties of TBBt are believed to be associated with the inactivation of the mitogen-activated protein kinase (MAPK) and nuclear factor κB (NF-κB) signaling pathways. In conclusion, these findings suggest that inhibiting CK2α could be a promising therapeutic strategy for treating sepsis-induced AKI.

Nanospanlastics as a Novel Approach for Improving the Oral Delivery of Resveratrol in Lipopolysaccharide-Induced Endotoxicity in Mice

Purpose

Resveratrol (RSV) is a natural polyphenolic compound that has numerous biological effects. Owing to its poor bioavailability, only trace concentrations of RSV could be found at the site of action. Therefore, the present study was aimed at developing RSV-loaded nanospanlastics to improve its oral delivery and therapeutic activity.

Methods

RSV-loaded nanospanlastics were prepared using the thin film hydration technique. The developed formulations were characterized via vesicular size (VS), polydispersity index (PDI), zeta potential (ZP) measurements, fourier transform infrared (FT-IR) spectroscopy analysis and transmission electron microscopy (TEM). In vitro release profile was carried out using dialysis bag diffusion technique. In vivo study was carried out using lipopolysaccharide (LPS)-induced endotoxicity model in mice to evaluate the formulations activity.

Results

The results revealed the successful development of RSV-loaded nanospanlastics which exhibited EE% ranging from 45 to 85%, particle sizes ranging from 260.5 to 794.3 nm; negatively charged zeta potential (≤ − 20 mV) and TEM revealed their spherical shape. An in vitro release study showed biphasic pattern with sustained release of drug up to 24 h. In vivo results showed the superiority of RSV-loaded nanospanlastics over conventional niosomes in attenuating serum levels of liver and kidney functions (aspartate transaminase (AST), alanine transaminase (ALT), and creatinine) in LPS-induced endotoxic mice. Furthermore, both of them suppressed the elevated oxidative stress and inflammatory markers (malondialdehyde (MDA), nitric oxide (NO), and interleukin-1beta (IL-1β)) estimated in the liver and kidney tissues. However, the nanospanlastics showed a prevalence effect over conventional niosomes in kidney measurements and the histopathological examinations.

Conclusions

These findings reveal the potential of nanospanlastics in improving the oral delivery and therapeutic efficacy of RSV.

The Chelating Ability of Plant Polyphenols Can Affect Iron Homeostasis and Gut Microbiota

In the past decades, many studies have widely examined the effects of dietary polyphenols on human health. Polyphenols are well known for their antioxidant properties and for their chelating abilities, by which they can be potentially employed in cases of pathological conditions, such as iron overload. In this review, we have highlighted the chelating abilities of polyphenols, which are due to their structural specific sites, and the differences for each class of polyphenols. We have also explored how the dietary polyphenols and their iron-binding abilities can be important in inflammatory/immunomodulatory responses, with a special focus on the involvement of macrophages and dendritic cells, and how they might contribute to reshape the gut microbiota into a healthy profile. This review also provides evidence that the axes “polyphenol–iron metabolism–inflammatory responses” and “polyphenol–iron availability–gut microbiota” have not been very well explored so far, and the need for further investigation to exploit such a potential to prevent or counteract pathological conditions.

In Vitro Anti-Inflammatory and Antioxidant Activities of pH-Responsive Resveratrol-Urocanic Acid Nano-Assemblies

Inflammatory environments provide vital biochemical stimuli (i.e., oxidative stress, pH, and enzymes) for triggered drug delivery in a controlled manner. Inflammation alters the local pH within the affected tissues. As a result, pH-sensitive nanomaterials can be used to effectively target drugs to the site of inflammation. Herein, we designed pH-sensitive nanoparticles in which resveratrol (an anti-inflammatory and antioxidant compound (RES)) and urocanic acid (UA) were complexed with a pH-sensitive moiety using an emulsion method. These RES-UA NPs were characterized by transmission electron microscopy, dynamic light scattering, zeta potential, and FT-IR spectroscopy. The anti-inflammatory and antioxidant activities of the RES-UA NPs were assessed in RAW 264.7 macrophages. The NPs were circular in shape and ranged in size from 106 to 180 nm. The RES-UA NPs suppressed the mRNA expression of the pro-inflammatory molecules inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages in a concentration-dependent manner. Incubation of LPS-stimulated macrophages with RES-UA NPs reduced the generation of reactive oxygen species (ROS) in a concentration-dependent manner. These results suggest that pH-responsive RES-UA NPs can be used to decrease ROS generation and inflammation.

The Response of Macrophages in Sepsis-Induced Acute Kidney Injury

Sepsis-induced acute kidney injury (SAKI) is common in critically ill patients and often leads to poor prognosis. At present, the pathogenesis of SAKI has not been fully clarified, and there is no effective treatment. Macrophages are immune cells that play an important role in the pathogenesis of SAKI. The phenotype and role of macrophages can vary from early to later stages of SAKI. Elucidating the role of macrophages in SAKI will be beneficial to its diagnosis and treatment. This article reviews past studies describing the role of macrophages in SAKI, with the aim of identifying novel therapeutic targets.

Resveratrol improved kidney function and structure in malignantly hypertensive rats by restoration of antioxidant capacity and nitric oxide bioavailability

BACKGROUND

The main cause of death among patients with malignant hypertension is a kidney failure. The promising field in essential and malignant hypertension therapy could be centered on the amelioration of oxidative stress using antioxidant molecules like resveratrol. Resveratrol is a potent antioxidative agent naturally occurred in many plants that possess health-promoting properties.

METHODS

In the present study, we investigated the therapeutic potential of resveratrol, a polyphenol with anti-oxidative activity, in N^G-L-Arginine Methyl Ester (L-NAME) treated spontaneously hypertensive rats (SHR) - malignantly hypertensive rats (MHR).

RESULTS

Resveratrol significantly improves oxidative damages by modulation of antioxidant enzymes and suppression of prooxidant factors in the kidney tissue of MHR. Enhanced antioxidant defense in the kidney improves renal function and ameliorates the morphological changes in this target organ. Besides, protective properties of resveratrol are followed by the restoration of the nitrogen oxide (NO) pathway. 4) Conclusion: Antioxidant therapy with resveratrol could represent promising therapeutical approach in hypertension, especially malignant, against kidney damage.

Targeting microbiota-host interactions with resveratrol on cancer: Effects and potential mechanisms of action

Resveratrol (RSV) is a natural polyphenolic compound detected in grapes, berries, and red wine. The anticancer activities of RSV have been observed in vivo and in vitro studies. However, the pharmacology mechanism of RSV is confusing due to its low bioavailability. According to studies of the metabolic characteristics of RSV, the gut intestine is a crucial site of its health benefits. Dietary RSV exhibits a profound effect on the gut microbiota structure and metabolic function. In addition, emerging evidence demonstrates a protective effect of RSV metabolites against carcinogenesis. Therefore, to better understand the anticancer mechanisms of dietary RSV, it is vital to evaluate the role of RSV-microbiota-host interactions in cancer therapy. In this review, we summarized significant findings on the anticancer activities of RSV based on epidemiological, experimental and clinical studies involved in investigating the metabolic characteristics and the traditional anticancer mechanisms of RSV. Special attention is given to the putative mechanisms involving microbiota-host interactions, such as the modulation of gut microecology and the anticancer effects of RSV metabolites. The changes in microbiota-host interactions after RSV supplementation play vital roles in cancer prevention and thus offering a new perspective on nutritional interventions to treat cancer.

Resveratrol and Its Analogue 4,4′-Dihydroxy-trans-stilbene Inhibit Lewis Lung Carcinoma Growth In Vivo through Apoptosis, Autophagy and Modulation of the Tumour Microenvironment in a Murine Model

Lung cancer is the most prevalent cancer worldwide. Despite advances in surgery and immune-chemotherapy, the therapeutic outcome remains poor. In recent years, the anticancer properties of natural compounds, along with their low toxic side effects, have attracted the interest of researchers. Resveratrol (RSV) and many of its derivatives received particular attention for their beneficial bioactivity. Here we studied the activity of RSV and of its analogue 4,4′-dihydroxystilbene (DHS) in C57BL/6J mice bearing cancers resulting from Lung Lewis Carcinoma (LLC) cell implantation, considering tumour mass weight, angiogenesis, cell proliferation and death, autophagy, as well as characterization of their immune microenvironment, including infiltrating cancer-associated fibroblasts (CAFs). C57BL/6J mice started treatment with RSV or DHS, solubilised in drinking water, one week before LLC implantation, and continued for 21 days, at the end of which they were sacrificed, and the tumour masses collected. Histology was performed according to standard procedures; angiogenesis, cell proliferation and death, autophagy, infiltrating-immune cells, macrophages and fibroblasts were assessed by immunodetection assays. Both stilbenic compounds were able to contrast the tumour growth by increasing apoptosis and autophagy in LLC tumour masses. Additionally, they contrasted the tumour-permissive microenvironment by limiting the infiltration of tumour-associated immune-cells and, more importantly, by counteracting CAF maturation. Therefore, both stilbenes could be employed to synergise with conventional oncotherapies to limit the contribution of stromal cells in tumour growth.

Macrophage Polarization and Reprogramming in Acute Inflammation: A Redox Perspective

Macrophage polarization refers to the process by which macrophages can produce two distinct functional phenotypes: M1 or M2. The balance between both strongly affects the progression of inflammatory disorders. Here, we review how redox signals regulate macrophage polarization and reprogramming during acute inflammation. In M1, macrophages augment NADPH oxidase isoform 2 (NOX2), inducible nitric oxide synthase (iNOS), synaptotagmin-binding cytoplasmic RNA interacting protein (SYNCRIP), and tumor necrosis factor receptor-associated factor 6 increase oxygen and nitrogen reactive species, which triggers inflammatory response, phagocytosis, and cytotoxicity. In M2, macrophages down-regulate NOX2, iNOS, SYNCRIP, and/or up-regulate arginase and superoxide dismutase type 1, counteract oxidative and nitrosative stress, and favor anti-inflammatory and tissue repair responses. M1 and M2 macrophages exhibit different metabolic profiles, which are tightly regulated by redox mechanisms. Oxidative and nitrosative stress sustain the M1 phenotype by activating glycolysis and lipid biosynthesis, but by inhibiting tricarboxylic acid cycle and oxidative phosphorylation. This metabolic profile is reversed in M2 macrophages because of changes in the redox state. Therefore, new therapies based on redox mechanisms have emerged to treat acute inflammation with positive results, which highlights the relevance of redox signaling as a master regulator of macrophage reprogramming.

Perillaldehyde protects against Aspergillus fumigatus keratitis by reducing fungal load and inhibiting inflammatory cytokines and LOX-1

PURPOSE

The purpose of this research was to explore the antifungal and anti-inflammatory effects of perillaldehyde (PAE) in Aspergillus fumigatus (A.fumigatus) keratitis and the underlying mechanism.

METHODS

The biofilm formation, adherence assay, propidium iodide uptake test were used to determine the possible mechanism of PAE in terms of antifungal effects in vitro. The severity of corneal infection was evaluated by clinical scores. The immunofluorescence staining was adopt to detect the number of macrophages in infected corneas. Draize test was performed to assess the ocular toxicity of PAE. Real-time polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and Western blot reflected the expression of inflammatory cytokines and Lectin-like oxidized low-density lipoprotein receptor 1 (LOX-1) in mice corneas and RAW264.7 cells.

RESULTS

PAE was able to inhibit the formation of biofilm, reduce conidial adhesion, and damage the integrity of membranes to exert antifungal activity. In C57BL/6 mice models, PAE alleviated the severity of infected corneas, reduced the recruitment of macrophages and had low ocular toxicity. In addition, the mRNA and protein levels of TNF-α, CCL-2 and LOX-1 could be significantly decreased by the application of PAE after A.fumigatus infection in vivo and in vitro.

CONCLUSION

Our study indicated that PAE protected against A.fumigatus keratitis by reducing fungal load, accumulation of macrophages, and inhibiting the expression of inflammatory cytokines.

Polyphenols and Their Metabolites in Renal Diseases: An Overview

Kidney diseases constitute a worldwide public health problem, contributing to morbidity and mortality. The present study aimed to provide an overview of the published data regarding the potential beneficial effects of polyphenols on major kidney diseases, namely acute kidney injury, chronic kidney disease, diabetic nephropathy, renal cancer, and drug-induced nephrotoxicity. This study consists of a bibliographical review including in vitro and in vivo studies dealing with the effects of individual compounds. An analysis of the polyphenol metabolome in human urine was also conducted to estimate those compounds that are most likely to be responsible for the kidney protective effects of polyphenols. The biological effects of polyphenols can be highly attributed to the modulation of specific signaling cascades including those involved in oxidative stress responses, anti-inflammation processes, and apoptosis. There is increasing evidence that polyphenols afford great potential in renal disease protection. However, this evidence (especially when in vitro studies are involved) should be considered with caution before its clinical translation, particularly due to the unfavorable pharmacokinetics and extensive metabolization that polyphenols undergo in the human body. Future research should consider polyphenols and their metabolites that indeed reach kidney tissues.

Resveratrol: Potential Application in Sepsis

Sepsis is a life-threatening organ dysfunction syndrome caused by host response disorders due to infection or infectious factors and is a common complication of patients with clinical trauma, burns, and infection. Resveratrol is a natural polyphenol compound that is a SIRT-1 activator with anti-inflammatory, antiviral, antibacterial, antifungal inhibitory abilities as well as cardiovascular and anti-tumor protective effects. In recent years, some scholars have applied resveratrol in animal models of sepsis and found that it has an organ protective effect and can improve the survival time and reduce the mortality of animals with sepsis. In this study, Medline (Pubmed), embase, and other databases were searched to retrieve literature published in 2021 using the keywords “resveratrol” and “sepsis,” and then the potential of resveratrol for the treatment of sepsis was reviewed and prospected to provide some basis for future clinical research.

The Ability of Resveratrol to Attenuate Ovalbumin-Mediated Allergic Asthma Is Associated With Changes in Microbiota Involving the Gut-Lung Axis, Enhanced Barrier Function and Decreased Inflammation in the Lungs

Asthma is a chronic respiratory disease highly prevalent worldwide. Recent studies have suggested a role for microbiome-associated gut-lung axis in asthma development. In the current study, we investigated if Resveratrol (RES), a plant-based polyphenol, can attenuate ovalbumin (OVA)-induced murine allergic asthma, and if so, the role of microbiome in the gut-lung axis in this process. We found that RES attenuated allergic asthma with significant improvements in pulmonary functions in OVA-exposed mice when tested using plethysmography for frequency (F), mean volume (MV), specific airway resistance (sRaw), and delay time(dT). RES treatment also suppressed inflammatory cytokines in the lungs. RES modulated lung microbiota and caused an abundance of Akkermansia muciniphila accompanied by a reduction of LPS biosynthesis in OVA-treated mice. Furthermore, RES also altered gut microbiota and induced enrichment of Bacteroides acidifaciens significantly in the colon accompanied by an increase in butyric acid concentration in the colonic contents from OVA-treated mice. Additionally, RES caused significant increases in tight junction proteins and decreased mucin (Muc5ac) in the pulmonary epithelium of OVA-treated mice. Our results demonstrated that RES may attenuate asthma by inducing beneficial microbiota in the gut-lung axis and through the promotion of normal barrier functions of the lung.

The Programmed Cell Death of Macrophages, Endothelial Cells, and Tubular Epithelial Cells in Sepsis-AKI

Sepsis is a systemic inflammatory response syndrome caused by infection, following with acute injury to multiple organs. Sepsis-induced acute kidney injury (AKI) is currently recognized as one of the most severe complications related to sepsis. The pathophysiology of sepsis-AKI involves multiple cell types, including macrophages, vascular endothelial cells (ECs) and renal tubular epithelial cells (TECs), etc. More significantly, programmed cell death including apoptosis, necroptosis and pyroptosis could be triggered by sepsis in these types of cells, which enhances AKI progress. Moreover, the cross-talk and connections between these cells and cell death are critical for better understanding the pathophysiological basis of sepsis-AKI. Mitochondria dysfunction and oxidative stress are traditionally considered as the leading triggers of programmed cell death. Recent findings also highlight that autophagy, mitochondria quality control and epigenetic modification, which interact with programmed cell death, participate in the damage process in sepsis-AKI. The insightful understanding of the programmed cell death in sepsis-AKI could facilitate the development of effective treatment, as well as preventive methods.

Protective Effects of Carnosic Acid on Lipopolysaccharide-Induced Acute Kidney Injury in Mice

Septic acute kidney injury (AKI) is an important medical problem worldwide, but current treatments are limited. During sepsis, lipopolysaccharide (LPS) activates various signaling pathways involved in multiorgan failure. Carnosic acid is a natural phenolic diterpene and has multiple bioactivities, such as anti-tumor, anti-inflammatory, and anti-oxidative effects. However, the effect of carnosic acid on septic AKI has not been explored. Therefore, this study aimed to determine whether carnosic acid has a therapeutic effect on LPS-induced kidney injury. Administration of carnosic acid after LPS injection ameliorated histological abnormalities and renal dysfunction. Cytokine production, immune cell infiltration, and nuclear factor-κB activation after LPS injection were also alleviated by carnosic acid. The compound suppressed oxidative stress with the modulation of pro-oxidant and antioxidant enzymes. Tubular cell apoptosis and caspase-3 activation were also inhibited by carnosic acid. These data suggest that carnosic acid ameliorates LPS-induced AKI via inhibition of inflammation, oxidative stress, and apoptosis and could serve as a useful treatment agent for septic AKI.

A Review of Natural Products for Prevention of Acute Kidney Injury

BACKGROUND AND OBJECTIVES

acute kidney injury (AKI), formerly called acute renal failure (ARF), is commonly defined as an abrupt decline in renal function, clinically manifesting as a reversible acute increase in nitrogen waste products-measured by blood urea nitrogen (BUN) and serum creatinine levels-over the course of hours to weeks. AKI occurs in about 20% of all hospitalized patients and is more common in the elderly. Therefore, it is necessary to prevent the occurrence of AKI, and to detect and treat early, since it is known that a prolonged period of kidney injury increases cardiovascular complications and the risk of death. Despite advances in modern medicine, there are no consistent treatment strategies for preventing the progression to chronic kidney disease. Through many studies, the safety and efficacy of natural products have been proven, and based on this, the time and cost required for new drug development can be reduced. In addition, research results on natural products are highly anticipated in the prevention and treatment of various diseases. In relation to AKI, many papers have reported that many natural products can prevent and treat AKI.

CONCLUSIONS

in this paper, the results of studies on natural products related to AKI were found and summarized, and the mechanism by which the efficacy of AKI was demonstrated was reviewed. Many natural products show that AKI can be prevented and treated, suggesting that these natural products can help to develop new drugs. In addition, we may be helpful to elucidate additional mechanisms and meta-analysis in future natural product studies.

Role of stilbenes against insulin resistance: A review

Insulin resistance (IR) is a state characterized by the inability of tissues to utilize blood glucose particularly liver, muscle, and adipose tissues resulting in hyperglycemia and hyperinsulinemia. A close relationship exists between IR and the development of type 2 diabetes (T2D). Therefore, therapeutic approaches to treat IR also improve T2D simultaneously. Scientific evidence has highlighted the major role of inflammatory cytokines, reactive oxygen species (ROS), environmental & genetic factors, and auto-immune disorders in the pathophysiology of IR. Among therapeutic remedies, nutraceuticals like polyphenols are being used widely to ameliorate IR due to their safer nature compared to pharmaceutics. Stilbenes are considered important metabolically active polyphenols currently under the limelight of research to cope with IR. In this review, efforts are made to elucidate cellular and subcellular mechanisms influenced by stilbenes including modulating insulin signaling cascade, correcting glucose transport pathways, lowering postprandial glucose levels, and protecting β-cell damage and its effects on the hyperactive immune system and proinflammatory cytokines to attenuate IR. Furthermore, future directions to further the research in stilbenes as a strong candidate against IR are included so that concrete recommendation for their use in humans is made.

Humanized anti‑TLR4 monoclonal antibody ameliorates lipopolysaccharide‑related acute kidney injury by inhibiting TLR4/NF‑κB signaling

A humanized anti‑Toll‑like receptor 4 (TLR4) monoclonal antibody (mAb) was previously produced using phage antibody library technology, and it was found that the mAb could effectively ameliorate lipopolysaccharide (LPS)‑induced damage in macrophages. The present study investigated the protective effects exerted by the humanized anti‑TLR4 mAb against LPS‑induced acute kidney injury (AKI), as well as the underlying mechanisms. Female C57BL/6 mice were randomly divided into four groups (n=8 per group): i) Control; ii) LPS; iii) LPS + humanized anti‑TLR4 mAb (1 µg/g); and iv) LPS + humanized anti‑TLR4 mAb (10 µg/g). Serum creatinine, blood urea nitrogen, IL‑6, TNFα and IL‑1β levels were then examined, followed by renal pathology assessment, immunohistochemical staining, reverse transcription‑quantitative PCR and western blotting to assess apoptosis/survival/inflammation‑related molecules and kidney injury molecule (KIM)‑1. The humanized anti‑TLR4 mAb successfully ameliorated LPS‑induced AKI and renal pathological damage. The humanized anti‑TLR4 mAb also dose‑dependently suppressed LPS‑induced elevations in serum IL‑6, TNFα and IL‑1β, and decreased the renal expression levels of myeloid differentiation primary response 88 (MyD88), IKKα/β, IκB, p65 and KIM‑1. Compared with the LPS group, renal Bax and KIM‑1 expression levels were significantly downregulated, and Bcl‑2 expression was notably upregulated by the humanized anti‑TLR4 mAb. Moreover, the humanized anti‑TLR4 mAb also significantly decreased the protein expression levels of MyD88, phosphorylated (p)‑IKKα/β, p‑IκB and p‑p65 in the renal tissues compared with the LPS group. Therefore, the present study indicated that the anti‑inflammatory effects of the humanized anti‑TLR4 mAb against LPS‑related AKI in mice were mediated via inhibition of the TLR4/NF‑κB signaling pathway.

Prospective Pharmacological Potential of Resveratrol in Delaying Kidney Aging

Aging is an unavoidable part of life. The more aged we become, the more susceptible we become to various complications and damages to the vital organs, including the kidneys. The existing drugs for kidney diseases are mostly of synthetic origins; thus, natural compounds with minimal side-effects have attracted growing interest from the scientific community and pharmaceutical companies. A literature search was carried out to collect published research information on the effects of resveratrol on kidney aging. Recently, resveratrol has emerged as a potential anti-aging agent. This versatile polyphenol exerts its anti-aging effects by intervening in various pathologies and multi-signaling systems, including sirtuin type 1, AMP-activated protein kinase, and nuclear factor-κB. Researchers are trying to figure out the detailed mechanisms and possible resveratrol-mediated interventions in divergent pathways at the molecular level. This review highlights (i) the causative factors implicated in kidney aging and the therapeutic aspects of resveratrol, and (ii) the effectiveness of resveratrol in delaying the aging process of the kidney while minimizing all possible side effects.

Roflumilast improves resolution of sepsis-induced acute kidney injury by retarding late phase renal interstitial immune cells infiltration and leakage in urinary sediments

Some evidence has demonstrated that both inflammation and immune cell dysregulation are coincident at late phase (post 24 h) of sepsis. The present study was designed to determine the pathological role of hyperinflammation and renal immune cells mobilization during late phase of sepsis induced acute kidney injury (S-AKI) and tests the pharmacological effects of PDE-4 inhibitor on these events. Sepsis was induced by cecal ligation puncture and renal function, oxidative-inflammatory stress biomarkers were assessed after 24 h. PDE-4 inhibitor was administered for 7 days prior to induction of S-AKI. Renal immune cells infiltration during sepsis was analyzed by H&E staining and papanicolaou staining method was used for detecting leukocytes and cast in urinary sediments, periodic acid schiff (PAS) staining was used for detection of brush border loss. AKI developed 24 h post sepsis insult as depicted by increase in serum creatinine, blood urea nitrogen (BUN), renal oxidative stress, and elevated inflammatory biomarkers levels. Moreover, septic rats displayed increased bacterial load, renal expression of phosphodiesterase-4B, 4D isoforms, enhanced vascular permeability, caspase-3 and myeloperoxidase activity, electrolyte imbalance, reduced Na⁺ K⁺ ATPase activity, declined cAMP levels, increased interstitial leukocyte infiltration, and leakage in urinary sediments along with histological alterations. Pre-treatment with roflumilast at high dose completely prevented the various AKI associated manifestations in septic rats. Renal hyper-inflammation and leukocyte infiltration was detected in late phase of S-AKI. Roflumilast pre-treatment resolved sepsis induced renal dysfunction and histological damage by suppressing late phase renal immune cells invasion and anti-inflammatory effects mediated by up-regulation of renal cAMP levels.

Wedelolactone improves the renal injury induced by lipopolysaccharide in HK-2 cells by upregulation of protein tyrosine phosphatase non-receptor type 2

Objective

To explore the effects of wedelolactone (WEL) on sepsis-induced renal injury in the human renal proximal tubular epithelial cell line HK-2.

Methods

HK-2 cells were stimulated by 1 µg/ml lipopolysaccharide (LPS) to trigger renal injury in vitro. HK-2 cells were pretreated with or without WEL (0.1, 1 and 10 µM) before LPS stimulation. Protein and mRNA analyses were performed using enzyme-linked immunosorbent assays, Western blot analysis and quantitative reverse transcription–polymerase chain reaction. The MTT assay and flow cytometry were used to measure cell viability and the rate of cell apoptosis. Protein tyrosine phosphatase non-receptor type 2 (PTPN2) knockdown was induced by the transection of HK-2 cells with short hairpin RNA.

Results

Cell viability was significantly increased in a dose-dependent manner by WEL in LPS-induced HK-2 cells. WEL also decreased the levels of four inflammatory cytokines and cell apoptosis in LPS-induced HK-2 cells. The level of PTPN2 was increased after WEL treatment. PTPN2 knockdown partly abolished the inhibitory effects of WEL on cell apoptosis, the levels of inflammatory cytokines and on p38 mitogen-activated protein kinase/nuclear factor-kappaB signalling in LPS-induced HK-2 cells.

Conclusion

WEL improved renal injury by suppressing inflammation and cell apoptosis through upregulating PTPN2 in HK-2 cells. PTPN2 might be used as a potential therapeutic target for LPS-induced sepsis.

Toll-Like Receptors in Acute Kidney Injury

Acute kidney injury (AKI) is an important health problem, affecting 13.3 million individuals/year. It is associated with increased mortality, mainly in low- and middle-income countries, where renal replacement therapy is limited. Moreover, survivors show adverse long-term outcomes, including increased risk of developing recurrent AKI bouts, cardiovascular events, and chronic kidney disease. However, there are no specific treatments to decrease the adverse consequences of AKI. Epidemiological and preclinical studies show the pathological role of inflammation in AKI, not only at the acute phase but also in the progression to chronic kidney disease. Toll-like receptors (TLRs) are key regulators of the inflammatory response and have been associated to many cellular processes activated during AKI. For that reason, a number of anti-inflammatory agents targeting TLRs have been analyzed in preclinical studies to decrease renal damage during AKI. In this review, we updated recent knowledge about the role of TLRs, mainly TLR4, in the initiation and development of AKI as well as novel compounds targeting these molecules to diminish kidney injury associated to this pathological condition.

Autophagy Activation by Resveratrol Reduces Severity of Experimental Rheumatoid Arthritis

SCOPE

Previous work reported that dietary supplementation with resveratrol lowers synovial hyperplasia, inflammatory and oxidative damage in an antigen-induced arthritis (AIA) model. Here, it is investigated whether resveratrol can regulate the abnormal synovial proliferation by inducing autophagy and controlling the associated inflammatory response.

METHODS AND RESULTS

Animals treated with resveratrol 8 weeks before AIA induction show the highest significant signal for microtubule-associated protein 1 light chain 3 by confocal microscopy. Besides, resveratrol significantly reduces p62 expression, but it does not increase the signal of beclin-1. Also, active caspase-3 expression, as well as poly(ADP-ribose) polymerase, is upregulated in the AIA group, and is significantly reduced in resveratrol-treated AIA group. Resveratrol also mitigates angiopoietin-1 and vascular endothelial growth factor signals. Finally, resveratrol significantly reduces the serum levels of IL-1β, C reactive protein, and prostaglandin E2, as well as nuclear factor κB synovial tissue expression, which shows a significant correlation with p62 expression.

CONCLUSION

Dietary supplementation with resveratrol induces the noncanonical autophagy pathway and limits the cross-talk with inflammation, which in consequence modulates the synovial hyperplasia. Preventive strategies that incorporate dietary intervention with resveratrol may offer a potential therapeutic alternative to drugs to influence the risk of rheumatoid arthritis and influence its course.

Mono-macrophage-Derived MANF Protects Against Lipopolysaccharide-Induced Acute Kidney Injury via Inhibiting Inflammation and Renal M1 Macrophages

The outburst of renal inflammatory response has been found to be a crucial cause of acute kidney injury (AKI). Attenuating the renal inflammation is an effective way for AKI treatment. Mesencephalic astrocyte-derived neurotrophic factor (MANF) has been proven to be an anti-inflammatory factor. However, the effect of MANF on renal inflammation induced by AKI is unknown. In this study, we have investigated the effect of mono-macrophage-derived MANF on AKI. We constructed the mono-macrophage-specific MANF knockout (Mø MANF^-/-) mouse and used lipopolysaccharide (LPS) to induce AKI in wild-type (WT) and Mø MANF^-/- mice. With mono-macrophage-specific MANF deficiency, Mø MANF^-/- mice had a lower survival rate, more severe renal injury, and higher serum level of pro-inflammatory TNF-α after AKI was induced by LPS. Also, compared with WT mice, there were more M1 macrophages in renal tissues of Mø MANF^-/- mice with LPS treatment, which might be attributed to the enhanced NF-κB activation in the renal microenvironment. Our study indicates the immunoregulatory role of mono-macrophage-derived MANF in the pathophysiological process of AKI, as well as the potential clinical application of MANF for AKI treatment.

Gemcitabine potentiates anti-tumor effect of resveratrol on pancreatic cancer via down-regulation of VEGF-B

PURPOSE

In our previous study, we discovered that resveratrol (RSV) had potential tumor-promoting effect on pancreatic cancer (PaCa) via up-regulation of VEGF-B. Therefore, we assumed that a pharmacological inhibitor of VEGF-B should potentiate the anti-tumor effect of RSV on PaCa.

METHODS

Real-time PCR and western blotting were used to examine VEGF-B mRNA and protein levels. Cell viability and cell apoptosis were assessed by CCK-8 assay and flow cytometry analysis, respectively. PaCa cell-bearing nude mice were used to evaluate the anti-cancer effects of single treatment or co-administration of RSV and gemcitabine (GEM).

RESULTS

We found that treatment with GEM alone dramatically decreased VEGF-B expression in comparison with control group, indicating that GEM is a potential pharmacological inhibitor of VEGF-B in PaCa. The co-administration of RSV and GEM significantly lowered expression of VEGF-B and increased phosphorylation level of GSK3β at Ser9 when compared to RSV alone treatment either in vitro or in vivo. Combination of RSV and GEM significantly increased cell death and apoptosis of PaCa cells in vitro and inhibited tumor growth in vivo in comparison with RSV or GEM alone treatment. Furthermore, we found that the anti-tumor effect in combination group was dramatically weakened after VEGF-B overexpressed in PaCa cells.

CONCLUSION

These results suggest that VEGF-B signaling pathway plays an important role in the development of PaCa and combination of GEM and RSV would be a promising modality for clinical PaCa therapy.

Effects of resveratrol on the inflammatory response and renal injury in hyperuricemic rats

BACKGROUND/OBJECTIVES

Hyperuricemic nephropathy is a common cause of acute kidney injury. Resveratrol can ameliorate kidney injury, but the explicit mechanism remains unclear. We investigated the effects of resveratrol on the inflammatory response and renal injury in hyperuricemic rats.

MATERIALS/METHODS

A rat model of hyperuricemic nephropathy was established by the oral administration of a mixture of adenine and potassium oxinate. Biochemical analysis and hematoxylin and eosin staining were performed to assess the rat kidney function. Enzyme-linked immunosorbent assays were performed to evaluate the immune and oxidative responses.

RESULTS

The expression levels of urine albumin and β2-microglobulin were significantly decreased after resveratrol treatment. In addition, the levels of serum creatinine and uric acid were significantly decreased in the resveratrol groups, compared with the control group. The levels of proinflammatory factors, such as interleukin-1β and tumor necrosis factor-α, in kidney tissue and serum were also increased in the hyperuricemic rats, and resveratrol treatment inhibited their expression. Moreover, the total antioxidant capacity in kidney tissue as well as the superoxide dismutase and xanthine oxidase levels in serum were all decreased by resveratrol treatment.

CONCLUSIONS

Resveratrol may protect against hyperuricemic nephropathy through regulating the inflammatory response.

Antioxidant, Anti-Inflammatory and Antiproliferative Effects of the Vitis vinifera L. var. Fetească Neagră and Pinot Noir Pomace Extracts

The pathophysiology of inflammation and oxidative stress generated during different types of cancers and anticancer treatments is well documented. Traditionally, grape pomace is used for animal feed, organic fertilizers, ethanol production or is disposed as waste. Because grape pomace is a rich source of antioxidant compounds, the purpose of the study was to evaluate the antioxidant, anti-inflammatory, and antiproliferative effects of fresh and fermented grape pomace extracts of two Vitis vinifera L. varieties Fetească neagră and Pinot noir cultivated in Romania. Firstly, grape pomace phytochemical analysis and in vitro antioxidant tests were performed. Secondly, the effect of a seven-day pretreatment with grape pomace extracts on the turpentine oil-induced inflammation in rats was assessed by measuring total oxidative status, total antioxidant response, oxidative stress index, malondialdehyde, total thiols, nitric oxide and 3-nitrotyrosine. Thirdly, the antiproliferative properties were evaluated on human lung carcinoma (A549), human breast adenocarcinoma (MDA-MB-231), murine melanoma (B164A5), and keratinocyte (HaCat) cell lines. Fetească neagră and Pinot noir grape pomace extracts have a rich content of polyphenols and in vitro antioxidant effect. Fermented samples had higher polyphenol content, but fresh samples had better antioxidant activity. Pretreatment with grape pomace extracts reduced inflammation-induced oxidative stress in a concentration-dependent way, fresh samples being more efficient. The malignant cells' proliferation was inhibited by all grape pomace extracts, fermented Fetească neagră extracts having the strongest effect. Conclusion: fresh and fermented pomace extracts of Vitis vinifera L. varieties Fetească neagră and Pinot noir cultivated in a Romanian wine region have antioxidant, anti-inflammatory and antiproliferative effects.

Alterations in the Gut Microbiome and Suppression of Histone Deacetylases by Resveratrol Are Associated with Attenuation of Colonic Inflammation and Protection Against Colorectal Cancer

Inflammatory bowel disease (IBD) is known to significantly increase the risk for development of colorectal cancer (CRC), suggesting inflammation and cancer development are closely intertwined. Thus, agents that suppress inflammation may prevent the onset of cancer. In the current study, we used resveratrol, an anti-inflammatory stilbenoid, to study the role of microbiota in preventing inflammation-driven CRC. Resveratrol treatment in the azoxymethane (AOM) and dextran sodium sulphate (DSS) CRC murine model caused an increase in anti-inflammatory CD4 + FOXP3 + (Tregs) and CD4 + IL10 + cells, a decrease in proinflammatory Th1 and Th17 cells, and attenuated CRC development. Gut microbial profile studies demonstrated that resveratrol altered the gut microbiome and short chain fatty acid (SCFA), with modest increases in n-butyric acid and a potential butyrate precursor isobutyric acid. Fecal transfer from resveratrol-treated CRC mice and butyrate supplementation resulted in attenuation of disease and suppression of the inflammatory T cell response. Data also revealed both resveratrol and sodium butyrate (BUT) were capable of inhibiting histone deacetylases (HDACs), correlating with Treg induction. Analysis of The Cancer Genome Atlas (TCGA) datasets revealed increased expression of Treg-specific transcription factor FoxP3 or anti-inflammatory IL-10 resulted in an increase in 5-year survival of patients with CRC. These data suggest that alterations in the gut microbiome lead to an anti-inflammatory T cell response, leading to attenuation of inflammation-driven CRC.

Renoprotective Mono- and Triterpenoids from the Fruit of Gardenia jasminoides

This paper describes the isolation and characterization of 17 new and 12 known terpenoids from the fruit of Gardenia jasminoides. The structures of eight new triterpenoids and nine new monoterpenoids, including their absolute configurations, were defined by spectroscopic analysis in combination of quantum chemical electronic circular dichroism (ECD), vibrational circular dichroism (VCD), and gauge-independent atomic orbital (GIAO) NMR calculations. The cytoprotective effects of the isolated compounds against lipopolysaccharide (LPS)-induced apoptosis in normal rat kidney tubule epithelioid (NRK 52e) cells were investigated in vitro. Compounds 10, 18, 20, 21, 24, and 26 exhibited significant protective effects with EC₅₀ values from 14.2 nM to 1.6 μM.

Breaking the vicious loop between inflammation, oxidative stress and coagulation, a novel anti-thrombus insight of nattokinase by inhibiting LPS-induced inflammation and oxidative stress

Thrombosis is a principle cause of cardiovascular disease, the leading cause of morbidity and mortality worldwide; however, the conventional anti-thrombotic approach often leads to bleeding complications despite extensive clinical management and monitoring. In view of the intense crosstalk between inflammation and coagulation, plus the contributing role of ROS to both inflammation and coagulation, it is highly desirable to develop safer anti-thrombotic agent with preserved anti-inflammatory and anti-oxidative stress activities. Nattokinase (NK) possesses many beneficial effects on cardiovascular system due to its strong thrombolytic and anticoagulant activities. Herein, we demonstrated that NK not only effectively prevented xylene-induced ear oedema in mice, but also remarkably protected against LPS-induced acute kidney injury in mice through restraining inflammation and oxidative stress, a central player in the initiation and progression of inflammation. Fascinatingly, in line with our in vivo data, NK elicited prominent anti-inflammatory activity in RAW264.7 macrophages via suppressing the LPS-induced TLR4 and NOX2 activation, thereby repressing the corresponding ROS production, MAPKs activation, and NF-κB translocation from the cytoplasm to the nucleus, where it mediates the expression of pro-inflammatory mediators, such as TNF-α, IL-6, NO, and PAI-1 in activated macrophage cells. In particular, consistent with the macrophage studies, NK markedly inhibited serum PAI-1 levels induced by LPS, thereby blocking the deposition of fibrin in the glomeruli of endotoxin-treated animals. In summary, we extended the anti-thrombus mechanism of NK by demonstrating the anti-inflammatory and anti-oxidative stress effects of NK in ameliorating LPS-activated macrophage signaling and protecting against LPS-stimulated AKI as well as glomeruler thrombus in mice, opening a comprehensive anti-thrombus strategy by breaking the vicious cycle between inflammation, oxidative stress and thrombosis.

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NK protects against LPS-induced AKI via inhibiting inflammation and oxidative stress.

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NK inhibits LPS-induced TRL4 and NOX2 activation in macrophages.

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NK inhibits inflammation and oxidative stress both in vitro and in vivo.

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NK inhibits LPS-induced PAI-I levels, thereby blocking glomerular thrombus in mice.

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NK may break the vicious loop between inflammation, oxidative stress and coagulation.

TRPM7 mediates kidney injury, endothelial hyperpermeability and mortality during endotoxemia

Sepsis is the main cause of mortality in patients admitted to intensive care units. During sepsis, endothelial permeability is severely augmented, contributing to renal dysfunction and patient mortality. Ca²⁺ influx and the subsequent increase in intracellular [Ca²⁺]_i in endothelial cells (ECs) are key steps in the establishment of endothelial hyperpermeability. Transient receptor potential melastatin 7 (TRPM7) ion channels are permeable to Ca²⁺ and are expressed in a broad range of cell types and tissues, including ECs and kidneys. However, the role of TRPM7 on endothelial hyperpermeability during sepsis has remained elusive. Therefore, we investigated the participation of TRPM7 in renal vascular hyperpermeability, renal dysfunction, and enhanced mortality induced by endotoxemia. Our results showed that endotoxin increases endothelial hyperpermeability and Ca²⁺ overload through the TLR4/NOX-2/ROS/NF-κB pathway. Moreover, endotoxin exposure was shown to downregulate the expression of VE-cadherin, compromising monolayer integrity and enhancing vascular hyperpermeability. Notably, endotoxin-induced endothelial hyperpermeability was substantially inhibited by pharmacological inhibition and specific suppression of TRPM7 expression. The endotoxin was shown to upregulate the expression of TRPM7 via the TLR4/NOX-2/ROS/NF-κB pathway and induce a TRPM7-dependent EC Ca²⁺ overload. Remarkably, in vivo experiments performed in endotoxemic animals showed that pharmacological inhibition and specific suppression of TRPM7 expression inhibits renal vascular hyperpermeability, prevents kidney dysfunction, and improves survival in endotoxemic animals. Therefore, our results showed that TRPM7 mediates endotoxemia-induced endothelial hyperpermeability, renal dysfunction, and enhanced mortality, revealing a novel molecular target for treating renal vascular hyperpermeability and kidney dysfunction during endotoxemia, sepsis, and other inflammatory diseases.

Anti-breast cancer activity of resveratrol encapsulated in liposomes

Resveratrol (RES) is a naturally occurring and effective drug for tumor prevention and treatment. However, its low levels of aqueous solubility, stability, and poor bioavailability limit its application, especially when used as a free drug. In this study, RES was loaded into peptide and sucrose liposomes (PSL) to enhance the physico-chemical properties of RES and exploit RES delivery mediated by liposomes to effectively treat breast cancer. RES loaded PSL (the complex: PSL@RES) were stable, had a good RES encapsulation efficiency, and prolonged RES-release in vitro. PSL@RES was exceptionally efficient for inhibiting the growth of cancer cells, as the IC50 of PSL@RES in MCF-7 cells was found to be only 20.89 μmol L-1. The therapeutic efficacy of PSL@RES was evaluated in mice bearing breast cancer. The results showed that PSL@RES at a dosage of 5 mg kg-1 was more effective than 10 mg kg-1 free RES, and PSL@RES inhibited tumor growth completely at a dosage of 10 mg kg-1. PSL@RES induced apoptosis in breast tumor by upregulation of p53 expression. This then downregulated Bcl-2 and upregulated Bax, thereby inducing Caspase-3 activation. More importantly, encapsulation of RES within peptide liposomes greatly reduced the toxicity of free RES to mice. Overall, the simple formulation of liposomal nanocarriers of RES developed in this study produces satisfactory outcomes to encourage further applications of liposomal carriers for the treatment of breast cancer.

Resveratrol Protects Against Renal Damage via Attenuation of Inflammation and Oxidative Stress in High-Fat-Diet-Induced Obese Mice

Oxidative stress and inflammation play an important role in the chronic kidney disease associated with obesity. Resveratrol (RSV) has been reported to exhibit a wide range of biological activities including antioxidant and anti-inflammatory properties. The objective of the present study was to investigate the effects of RSV on renal inflammation and oxidative stress in obese mice induced by high-fat diet. Male C57BL/6 mice were induced to have nephropathy associated obesity by high-fat diet for 12 weeks. After 8 weeks of feeding, oral supplementation with 100 mg RSV/kg body weight/day was applied with the high-fat-diet feeding for another 4 weeks. The results showed that RSV treatment protected against renal damage induced by high-fat diet, as evidenced by the decreased serum creatinine and urea nitrogen levels, alleviation of glomerular damage, and tubular vacuolization. In addition, RSV enhanced the antioxidant enzyme activity; improved the expression of genes related to inflammation; and decreased the malondialdehyde, tumor necrosis factor-α, and interleukin-6 concentrations in the kidney of high-fat-diet mice. In conclusion, RSV could alleviate renal damage in obese mice induced by high-fat diet via suppressing inflammation and oxidative stress.

Effect of ATM on inflammatory response and autophagy in renal tubular epithelial cells in LPS-induced septic AKI

The aim of the present study was to explore the role of ataxia-telangiectasia mutated (ATM) in lipopolysaccharide (LPS)-induced in vitro model of septic acute kidney injury (AKI) and the association between ATM, tubular epithelial inflammatory response and autophagy. The renal tubular epithelial cell HK-2 cell line was cultured and passaged, with HK-2 cell injury induced by LPS. The effects of LPS on HK-2 cell morphology, viability, ATM expression and inflammation were observed. Lentiviral vectors encoding ATM shRNA were constructed to knock down ATM expression in HK-2 cells. The efficiency of ATM knockdown in HK-2 cells was detected by western blot analysis and reverse transcription-quantitative PCR (RT-qPCR). HK-2 cells transfected with the ATM shRNA lentivirus were used for subsequent experiments. Following ATM knockdown, corresponding controls were set up, and the effects of ATM on inflammation and autophagy were detected in HK-2 cells using RT-qPCR, western blotting and ELISA. After LPS stimulation, the HK-2 cells were rounded into a slender or fusiform shape with poorly defined outlines. LPS treatment reduced cell viability in a partly dose-dependent manner. LPS increased the expression of tumor necrosis factor-α, interleukin (IL)-1β and IL-6, with the levels reaching its highest value at 10 µg/ml. IL-6 and IL-1β expression increased with increasing LPS concentration. These findings suggest that LPS reduced HK-2 cell viability whilst increasing the expression of inflammatory factors. Following transfection with ATM shRNA, expression levels of key autophagy indicators microtubule associated protein 1 light chain 3α I/II ratio and beclin-1 in the two ATM shRNA groups were also significantly reduced compared with the NC shRNA group. In summary, downregulation of ATM expression in HK-2 cells reduced LPS-induced inflammation and autophagy in sepsis-induced AKI in vitro, suggesting that LPS may induce autophagy in HK-2 cells through the ATM pathway leading to the upregulation of inflammatory factors.

Effects of resveratrol on alpha-amanitin-induced nephrotoxicity in BALB/c mice

Alpha-amanitin (α-AMA), the primary toxin of Amanita phalloides, is known to cause nephrotoxicity and hepatotoxicity. Resveratrol is an antioxidant that has shown efficacy in many nephrotoxicity models. The aim of this study was to investigate the effects of resveratrol against the early and late stages of α-AMA-induced nephrotoxicity, compared to those of silibinin, a well-known antidote for poisoning by α-AMA-containing mushrooms. Mice kidney tissues were obtained from five groups: (1) α-AMA + NS (simultaneous administration of α-AMA and normal saline), (2) α-AMA + SR (simultaneous administration of α-AMA and resveratrol), (3) α-AMA + 12R (resveratrol administration 12 h after α-AMA administration), (4) α-AMA + 24R (resveratrol administration 24 h after α-AMA administration), and (5) α-AMA + Sil (simultaneous administration of α-AMA and silibinin). Histomorphological and biochemical analyses were performed to evaluate kidney damage and oxidant-antioxidant status in the kidney. Scores of renal histomorphological damage decreased significantly in the early resveratrol treatment groups (α-AMA + SR and α-AMA + 12R), compared to those in the α-AMA + NS group (p < 0.05). Catalase levels increased significantly in the α-AMA + SR group, compared to those in the α-AMA + NS group (p < 0.001). Early resveratrol administration within 12 h after α-AMA ingestion may reverse the effects of α-AMA-induced nephrotoxicity, partly through its antioxidant action, thereby suggesting its potential as a treatment for poisoning by α-AMA-containing mushrooms.