2-Methoxyestradiol Protects Against Lung Ischemia/Reperfusion Injury by Upregulating Annexin A1 Protein Expression

Decoding the enigmatic estrogen paradox in pulmonary hypertension: delving into estrogen metabolites and metabolic enzymes

Pulmonary hypertension (PH) presents a puzzling sex bias, being more prevalent in women yet often less severe than in men, and the underlying reasons remain unclear. Studies using animal models, and limited clinical data have revealed a protective influence of exogenous estrogens, known as the estrogen paradox. Research suggests that beyond its receptor-mediated effects, estrogen acts through metabolites such as 2-ME2, 4-OHE2, and 16-OHE2, which are capable of exhibiting protective or detrimental effects in PH, prompting the need to explore their roles in PH to untangle sex differences and the estrogen paradox. Hypoxia disrupts the balance of estrogen metabolites by affecting the enzymes responsible for estrogen metabolism. Delving into the role of these metabolic enzymes not only illuminates the sex difference in PH but also provides a potential rationale for the estrogen paradox. This review delves into the intricate interplay between estrogen metabolites, metabolic enzymes, and PH, offering a deeper understanding of sex-specific differences and the perplexing estrogen paradox in the context of this condition.

Monomethyl fumarate attenuates lung Ischemia/Reperfusion injury by disrupting the GAPDH/Siah1 signaling cascade

Monomethyl fumarate (MMF), a potent anti-inflammatory agent used to treat multiple sclerosis, has demonstrated efficacy in various inflammatory and ischemia/reperfusion (IR) models; however, its impact on IR-induced acute lung injury (ALI) has not been explored. We investigated, for the first time, whether MMF attenuates lung IR injury through inhibition of the GAPDH/Siah1 signaling pathway. Rats were subjected to IR injury using an isolated perfused lung model, and proximity ligation assays were employed to evaluate the presence and distribution of the GAPDH/Siah1 complex. In vitro studies involved pretreating human primary alveolar epithelial cells (HPAECs) with MMF and/or inducing GAPDH overexpression or silencing, followed by exposure to hypoxia-reoxygenation. The findings revealed significantly reduced lung damage indicators, including edema, proinflammatory cytokines, oxidative stress and apoptosis, in MMF-treated rats. Notably, MMF treatment inhibited GAPDH/Siah1 complex formation and nuclear translocation, indicating that disruption of the GAPDH/Siah1 cascade was the primary cause of these improvements. Our in vitro studies on pretreated HPAECs corroborate these in vivo findings, further strengthening this interpretation. Our study results suggest that the protective effects of MMF against lung IR injury may be attributed, at least in part, to its ability to disrupt the GAPDH/Siah1 signaling cascade, thereby attenuating inflammatory and apoptotic responses. Given these encouraging results, MMF has emerged as a promising therapeutic candidate for the management of lung IR injury.

Ovary metabolome and cecal microbiota changes in aged laying hens supplemented with vitamin E

This study was aimed to evaluate the effect of vitamin E (VE) on laying performance, VE deposition, antioxidant capacity, immunity, follicle development, estrogen secretion, ovary metabolome, and cecal microbiota of laying hens. One hundred and twenty XinYang Black-Feathered laying hens (70 wk old) were randomly assigned to 2 groups (6 replicates of 20 birds), and fed a basal diet (containing 20 mg/kg VE, control (CON) group) and a basal diet supplemented with 20 mg/kg VE (VE group). The experiment lasted for 10 wk. Results showed that VE supplementation increased laying performance, antioxidant capacity, and immunity, as evidenced by increased (P < 0.05) performance (laying rate), antioxidant (glutathione peroxidase, total superoxide dismutase, total antioxidant capacity, and catalase) and immune (immunoglobulins) parameters, and decreased (P < 0.05) feed/egg ratio and malondialdehyde. Meanwhile, VE group had higher (P < 0.05) pregrade follicles, ovary index and serum estrogen levels than CON group. 16S rRNA sequencing showed that VE supplementation altered the cecal microbiota composition by increasing Bacteroides, Rikenellaceae_RC9_gut_group, Prevotellaceae_UCG-001 and Megamonas abundances and reducing Christensenellaceae_R-7_group abundance (at genus level), which are mainly associated with the production of short-chain fatty acids. Metabolomic profiling of the ovary revealed that the major metabolites altered by VE supplementation were mainly related to follicle development, estrogen secretion, anti-inflammatory, antioxidant, phototransduction, bile acid synthesis, and nutrient transport. Furthermore, changes in cecal microbiota (at genus level) and ovary metabolites were highly correlated with laying performance, antioxidant, and immune parameters. In summary, VE contributed to the laying performance of aged laying hens by enhancing antioxidant, immune, and ovarian functions, promoting follicle development and estrogen secretion, and regulating gut microbiota and ovary metabolites. These findings will provide a new perspective on the mechanisms of egg production in aged poultry ovaries.

Tocilizumab Reduces Lung Injury in a Rat Lung Ischemia and Reperfusion Model

OBJECTIVE

In this study, the effect of tocilizumab (TCZ) on lung tissue in lung ischemia-reperfusion (I/R) injury in rats was investigated.

MATERIAL AND METHODS

A total of 24 Wistar rats were divided into 4 equal groups, with 6 rats in each group: Left lung I/R was applied to I/R groups. In the I/R groups, the left lung hilum was clamped for 45 minutes, and then the clamp was removed and reperfused for 120 minutes. In the TCZ groups, 4 mg/kg and 8 mg/kg of TCZ were administered intraperitoneally to the rats 30 minutes before surgery.

RESULTS

The tumor necrosis factor-alpha mean value was not statistically significant between the groups (P = .091). Statistically significant results were observed between group I/R-TCZ (8 mg/kg) and group I/R for catalase. (P = .005). Statistically significant results were observed between group I/R-TCZ (8 mg/kg) and group I/R for malondialdehyde. (P = .009). The difference in total ischemia score between group I/R-TCZ (4 mg/kg) and group I/R-TCZ (8 mg/kg) and group I/R was statistically significant (P < .001). In terms of alveolar hemorrhage, there was a statistically significant difference between group I/R-TCZ (4 mg/kg) and group I/R-TCZ (8 mg/kg) and group I/R (P = .01 and P = .002, respectively). There was a statistically significant difference between group I/R-TCZ (8 mg/kg) and group I/R in terms of neutrophil accumulation (P = .01). In terms of interstitial edema, there was a statistically significant difference between group I/R-TCZ (4 mg/kg) and group I/R-TCZ (8 mg/kg) and group I/R (P = .006 and P = .001, respectively). In terms of pulmonary edema, there was a statistically significant difference between group I/R-TCZ (4 mg/kg) and group I/R-TCZ (8 mg/kg) and group I/R (P = .01 and P = .009, respectively).

CONCLUSION

Lung tissue may be affected by I/R injury and this damage can be reversed with the use of TCZ.

Targeting Rev-Erbα to protect against ischemia-reperfusion-induced acute lung injury in rats

BACKGROUND

The dysregulation of local circadian clock has been implicated in the pathogenesis of a broad spectrum of diseases. However, the pathophysiological role of intrinsic circadian clocks Rev-Erbα in ischemia-reperfusion (IR)-induced acute lung injury (ALI) remains unclear.

METHODS

The IR-ALI model was established by subjecting isolated perfused rat lungs to 40 min of ischemia followed by 60 min of reperfusion. Rats were randomly assigned to one of six groups: control, control + SR9009 (Rev-Erbα agonist, 50 mg/kg), IR, and IR + SR9009 at one of three dosages (12.5, 25, 50 mg/kg). Bronchoalveolar lavage fluids (BALF) and lung tissues were obtained and analyzed. In vitro experiments utilized mouse lung epithelial cells (MLE-12) exposed to hypoxia-reoxygenation (HR) and pretreated with SR9009 (10 µM/L) and Rev-Erbα siRNA.

RESULTS

SR9009 exhibited a dose-dependent reduction in lung edema in IR-ALI. It significantly inhibited the production of TNF-α, IL-6, and CINC-1 in BALF. Moreover, SR9009 treatment restored suppressed IκB-α levels and reduced nuclear NF-κB p65 levels in lung tissues. In addition, a SR9009 mitigated IR-induced apoptosis and mitogen-activated protein kinase (MAPK) activation in injured lung tissue. Finally, treatment with Rev-Erbα antagonist SR8278 abolished the protective action of SR9009. In vitro analyses showed that SR9009 attenuated NF-κB activation and KC/CXCL-1 levels in MLE-12 cells exposed to HR, and these effects were significantly abrogated by Rev-Erbα siRNA.

CONCLUSIONS

The findings suggest that SR9009 exerts protective effects against IR-ALI in a Rev-Erbα-dependent manner. SR9009 may provide a novel adjuvant therapeutic approach for IR-ALI.

Protective Effects of 2-Methoxyestradiol on Acute Isoproterenol-Induced Cardiac Injury in Rats

Myocardial injury (MI) is an important pathological driver of mortality worldwide., and arises as a result of imbalances between myocardial oxygen demand and supply. In MI, oxidative stress often leads to inflammatory changes and apoptosis. Current therapies for MI are known to cause various adverse effects. Consequently, the development of new therapeutic agents with a reduced adverse event profile is necessary. In this regard, 2-methoxyestradiol (2ME), the metabolic end-product of oestradiol, possesses anti-inflammatory and antioxidant properties. The aim of this research is to assess the impact of 2ME on cardiac injury caused by isoproterenol (ISO) in rats. Animals were separated into six groups; controls, and those receiving 2ME (1 mg/kg), ISO (85 mg/kg), ISO + 2ME (0.25 mg/kg), ISO + 2ME (0.5 mg/kg), and ISO + 2ME (1 mg/kg). 2ME significantly attenuated ISO-induced changes in electrocardiographic changes and the cardiac histological pattern. This compound also decreased lactate dehydrogenase activity, creatine kinase myocardial band and troponin levels. The ability of 2ME to act as an antioxidant was shown by a decrease in malondialdehyde concentration, and the restoration of glutathione levels and superoxide dismutase activity. Additionally, 2ME antagonized inflammation and cardiac cell apoptosis, a process determined to be mediated, at least partially, by suppression of Gal-3/TLR4/MyD88/NF-κB signaling pathway. 2ME offers protection against acute ISO-induced MI in rats and offers a novel therapeutic management option.

Evaluation of the therapeutic effects of oestradiol on the systemic inflammatory response and on lung injury caused by the occlusion of the proximal descending aorta in male rats

OBJECTIVES

Ischaemia and reperfusion-induced microvascular dysfunction is a serious problem encountered during a variety surgical procedures, leading to systemic inflammation and affecting remote organs, specially the lungs. 17β-Oestradiol reduces pulmonary repercussions from various acute lung injury forms. Here, we focused on the 17β-oestradiol therapeutic effects after aortic ischaemia and reperfusion (I/R) by evaluating lung inflammation.

METHODS

Twenty-four Wistar rats were submitted to I/R by insufflation of a 2-F catheter in thoracic aorta for 20 min. Reperfusion took 4 h and 17β-oestradiol (280 µg/kg, i.v.) was administered after 1 h of reperfusion. Sham-operated rats were controls. Bronchoalveolar lavage was performed and lung samples were prepared for histopathological analysis and tissue culture (explant). Interleukin (IL)-1β, IL-10 and tumour necrosis factor-α were quantified.

RESULTS

After I/R, higher number of leukocytes in bronchoalveolar lavage were reduced by 17β-oestradiol. The treatment also decreased leukocytes in lung tissue. I/R increased lung myeloperoxidase expression, with reduction by 17β-oestradiol. Serum cytokine-induced neutrophil chemoattractant 1 and IL-1β increased after I/R and 17β-oestradiol decreased cytokine-induced neutrophil chemoattractant 1. I/R increased IL-1β and IL-10 in lung explants, reduced by 17β-oestradiol.

CONCLUSIONS

Our results showed that 17β-oestradiol treatment performed in the period of reperfusion, modulated the systemic response and the lung repercussions of I/R by thoracic aortic occlusion. Thus, we can suggest that 17β-oestradiol might be a supplementary approach leading the lung deterioration after aortic clamping in surgical procedures.

Sulforaphane alleviates lung ischemia‑reperfusion injury through activating Nrf‑2/HO‑1 signaling

Oxidative stress and inflammation are both involved in the pathogenesis of lung ischemia-reperfusion (I/R) injury. Sulforaphane (SFN) is a natural product with cytoprotective, anti-inflammatory, and antioxidant properties. The present study hypothesized that SFN may protect against lung I/R injury via the regulation of antioxidant and anti-inflammatory-related pathways. A rat model of lung I/R injury was established, and rats were randomly divided into 3 groups: Sham group, I/R group, and SFN group. It was shown that SFN protected against a pathological inflammatory response via inhibition of neutrophil accumulation and in the reduction of the serum levels of the pro-inflammatory cytokines, IL-6, IL-1β, and TNF-α. SFN treatment also significantly inhibited lung reactive oxygen species production, decreased the levels of 8-OH-dG and malondialdehyde, and reversed the decrease in the antioxidant activities of the enzymes catalase, superoxide dismutase, and glutathione peroxidase in the lungs of the I/R treated rats. In addition, SFN ameliorated I/R-induced lung apoptosis in rats by suppressing Bax and cleaved caspase-3 levels and increased Bcl-2 expression. Furthermore, SFN treatment activated an Nrf2-related antioxidant pathway, as indicated by the increased nuclear transfer of Nrf2 and the downstream HO-1 and NADPH quinone oxidoreductase-1. In conclusion, these findings suggested that SFN protected against I/R-induced lung lesions in rats via activation of the Nrf2/HO-1 pathway and the accompanied anti-inflammatory and anti-apoptotic effects.

Alda-1 ameliorates air embolism-induced acute lung injury

OBJECTIVE

Evidence suggests that aldehyde dehydrogenase 2 (ALDH2) offers protection against damage caused by oxidative stress in diverse rodent models. Nonetheless, the effect of Alda-1, a compound that activates ALDH2, on acute lung injury (ALI) induced by air embolism (AE) remains unclear. The objective of this study was to explore the protective effects of Alda-1 in ALI induced by AE.

METHODS

A rat model of in situ isolated perfused lung was established to investigate AE-induced ALI. Air was infused into the pulmonary artery at 0.25 mL/min for 1 minute. Before inducing AE, different doses (10, 20, or 30 mg/kg) of Alda-1 were given through intraperitoneal injection. Pathological changes in lung tissue were assessed using hematoxylin-eosin staining. We performed Western blot analysis to assess the protein levels of ALDH2,4-hydroxy-trans-2-nonenal (4-HNE), Bcl-2, caspase-3, phosphatidylinositol 3-kinase (PI3K), Akt, IκB-α, and nuclear NF-κB.

RESULTS

Notably, AE results were demonstrated as harmful to the lungs, which is evidenced by intensified lung edema and disruption of lung tissue structure. Furthermore, AE caused a decrease in ALDH2 expression, increased accumulation of 4-HNE and MDA, infiltration of neutrophils, increased production of inflammatory cytokines, apoptosis, and upregulation of the PI3K/Akt and NF-κB signaling pathways within the lungs. Administration of a 20 mg/kg dose of Alda-1 alleviated the detrimental effects induced by AE.

CONCLUSION

Alda-1 shows promise in mitigating AE-induced ALI, possibly through the upregulation of ALDH2 expression and suppression of the PI3K/Akt and NF-κB signaling pathways. Further research is warranted to validate these findings and to explore their translational potential in human subjects.

A High-Fiber Diet or Dietary Supplementation of Acetate Attenuate Hyperoxia-Induced Acute Lung Injury

A high fiber diet (HFD) and dietary supplementation with acetate have been reported to have beneficial effects in a variety of diseases. We investigated the effects of a HFD and acetate supplementation on the gut microbiota and hyperoxia-induced acute lung injury (HALI) in mice. Mice were fed a control diet, HFD, or acetate supplementation for three weeks, and their gut microbiome composition, lung tissues, and bronchoalveolar lavage fluid (BALF) were examined after exposure to ambient air or hyperoxia. Both the HFD and acetate supplementation modified the gut microbiota community and increased the proportion of acetate-producing bacteria in mice exposed to hyperoxia. The HFD and acetate supplementation also increased the abundance of Bacteroides acidifaciens and reduced gut dysbiosis according to the ratio of Firmicutes to Bacteroidetes. Compared with hyperoxia-exposed mice fed a control diet, both the HFD and acetate supplementation significantly increased the survival time while reducing the severity of pulmonary edema and the concentrations of protein and inflammatory mediators in BALF. Moreover, the HFD and acetate supplementation reduced the production of free radicals, attenuated NF-κB signaling activation, and decreased apoptosis in the lung tissues. Overall, this study indicates that a HFD or acetate supplementation reduces the severity of HALI through alterations in the gut microbiota to exert anti-inflammatory effects.

Tight Junctions, the Epithelial Barrier, and Toll-like Receptor-4 During Lung Injury

Lung epithelium is constantly exposed to the environment and is critically important for the orchestration of initial responses to infectious organisms, toxins, and allergic stimuli, and maintenance of normal gaseous exchange and pulmonary function. The integrity of lung epithelium, fluid balance, and transport of molecules is dictated by the tight junctions (TJs). The TJs are formed between adjacent cells. We have focused on the topic of the TJ structure and function in lung epithelial cells. This review includes a summary of the last twenty years of literature reports published on the disrupted TJs and epithelial barrier in various lung conditions and expression and regulation of specific TJ proteins against pathogenic stimuli. We discuss the molecular signaling and crosstalk among signaling pathways that control the TJ structure and function. The Toll-like receptor-4 (TLR4) recognizes the pathogen- and damage-associated molecular patterns released during lung injury and inflammation and coordinates cellular responses. The molecular aspects of TLR4 signaling in the context of TJs or the epithelial barrier are not fully known. We describe the current knowledge and possible networking of the TLR4-signaling with cellular and molecular mechanisms of TJs, lung epithelial barrier function, and resistance to treatment strategies.

The protective effects of Mai-Luo-Ning injection against LPS-induced acute lung injury via the TLR4/NF-κB signalling pathway

BACKGROUND

Acute lung injury (ALI) is a severe inflammatory disorder associated with high morbidity and mortality rates. Various therapeutic strategies for ALI have been proposed over the last few decades; however, the treatment options remain limited. Mai-Luo-Ning injection (MLN), a traditional Chinese medical formulation, has been extensively used for the treatment of respiratory diseases. Nevertheless, the effects of MLN on ALI remain unclear.

PURPOSE

This study aimed to investigate the protective and therapeutic effects of MLN on lipopolysaccharide-induced ALI mouse models and RAW 264.7 cells, and further explore the underlying mechanism of these effects.

METHODS

The therapeutic activity of MLN was evaluated using an in vivo ALI model and an in vitro model of RAW 264.7 macrophages. UHPLC-ESI-Q-TOF-MS/MS was used to investigate the chemical constituents of the MLN. The material basis and potential protective mechanism of MLN were analyzed using network pharmacology. The roles of MLN in inhibiting the Toll-like receptor 4 (TLR4)/ nuclear factor kappa B (NF-κB) signalling pathway were investigated via western blotting, real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and immunofluorescence staining.

RESULTS

In vivo experiments demonstrated that MLN ameliorated LPS-induced histological changes in lung tissues and reduced lung wet/dry weight ratio, total protein concentration in the bronchoalveolar lavage fluid and myeloperoxidase activity. Furthermore, MLN downregulated the in vivo and in vitro expression of pro-inflammatory cytokines such as tumour necrosis factor-alpha, interleukin-6, and interleukin-1β. Network pharmacology analysis revealed that MLN could act synergistically through multiple targets and pathways and exert a protective effect, possibly through inhibiting TLR4/ NF-κB signalling pathways. Western blotting and immunofluorescence experiments further confirmed that MLN could regulate the expression of TLR4, MyD88, phospho-IκB-α, and phospho-NF-κB p65 in the TLR4/NF-κB signalling pathway and decrease the translocation of phospho-NF-κB p65 into the nucleus.

CONCLUSION

This study suggests that MLN has a potential protective effect against LPS-induced ALI, which might be associated with the inhibition of the TLR4/NF-κB signalling pathway. Therefore, MLN is worthy of further investigation as a potential candidate for the treatment of ALI in the future.

Acetate, a gut bacterial product, ameliorates ischemia-reperfusion induced acute lung injury in rats

Recent data suggest that short-chain fatty acids (SCFAs), the major fermentation product from gut microbial degradation of dietary fiber, have protective effects against renal ischemia-reperfusion (IR) injury, colitis, and allergic asthma. However, the effect of SCFAs on acute lung injury (ALI) caused by IR is still unclear. In this study, we examine whether SCFAs have protective effects against IR-induced ALI and explore possible protective mechanisms. IR-induced ALI was established by 40 min ischemia followed by 60 min reperfusion in isolated perfused rat lungs. Rats were randomly assigned to one of six groups: control, control + acetate (400 mg/kg), IR, and IR + acetate at one of three dosages (100, 200, 400 mg/kg). Bronchoalveolar lavage fluids (BALF) and lung tissues were obtained and analyzed at the end of the experiment. In vitro, mouse lung epithelial cells (MLE-12) subjected to hypoxia-reoxygenation (HR) were pretreated with acetate (25 mmol/L) and GPR41 or GPR43 siRNA. Acetate decreased lung weight gain, lung weight/body weight ratios, wet/dry weight ratios, pulmonary artery pressure, and protein concentration of the BALF in a dose-dependent manner for IR-induced ALI. Acetate also significantly inhibited the production of TNF-α, IL-6 and CINC-1 in the BALF. Moreover, acetate treatment restored suppressed IκB-α levels and reduced nuclear NF-κB p65 levels in lung tissues. In addition, acetate mitigated IR-induced apoptosis and tight junction disruption in injured lung tissue. In vitro analyses showed that acetate attenuated NF-κB activation and KC/CXCL-1 levels in MLE-12 cells exposed to HR. The protective effects of acetate in vitro were significantly abrogated by GPR41 or GPR43 siRNA. Acetate ameliorates IR-induced acute lung inflammation and its protective mechanism appears to be via the GPR41/43 signaling pathway. Based on our findings, acetate may provide a novel adjuvant therapeutic approach for IR-induced lung injury.

2-Methoxyestradiol inhibits carotid artery intimal hyperplasia induced by balloon injury via inhibiting JAK/STAT axis in rats

Intimal hyperplasia (IH) is a common complication of vascular interventional procedures that leads to narrowing of the vessel lumen. 2-Methoxyestradiol (2ME), an estrogen metabolite, has numerous pharmacological actions, including vasoprotective and antiproliferative activities. The present study aimed to evaluate the potential of 2ME, prepared as a self-nanoemulsifying drug delivery system (SNEDDS), to inhibit IH induced by balloon injury (BI) in the rat carotid artery. The prepared 2ME SNEDDS had a particle size of 119 ± 2.3 nm and a zeta potential of -7.1 ± 1.4 mV. Animals were divided into 5 groups, namely control, sham, BI, BI + 2ME (100 μg/kg), and BI + 2ME (250 μg/kg). The obtained data indicated that 2ME significantly inhibited IH as indicated by the histological and morphometric assessment of the intima, media and lumen areas. This was associated with enhanced expression of Bax and inhibited expression of Bcl2 mRNA. Furthermore, 2ME exhibited significant antioxidant properties as evidenced by prevention of malondialdehyde accumulation as well as superoxide dismutase and catalase enzymatic exhaustion. In addition, 2ME showed significant anti-inflammatory actions as it significantly inhibited vascular content of interleukin-6, tumor necrosis factor-alpha, and nuclear factor-κB. The observed vasoprotective activities of 2ME were accompanied by inhibition of Janus kinase/signal transducers and activators of transcription (JAK/STAT) protein expression. In conclusion, this study revealed that 2ME ameliorates balloon injury-induced IH in rats via suppressing JAK/STAT axis. This may help to develop new strategies to combat IH.

2-Methoxyestradiol TPGS Micelles Attenuate Cyclosporine A-Induced Nephrotoxicity in Rats through Inhibition of TGF-β1 and p-ERK1/2 Axis

The immunosuppressant cyclosporine A (CSA) has been linked to serious renal toxic effects. Although 2-methoxyestradiol (2ME) possesses a wide range of pharmacological abilities, it suffers poor bioavailability after oral administration. The purpose of this study was to evaluate the potential of 2ME loaded D-ɑ-tocopheryl polyethylene glycol succinate (TPGS) micelles to prevent CSA-induced nephrotoxicity in rats. A 2ME-TPGS was prepared and showed particle size of 44.3 ± 3.5 nm with good entrapment efficiency and spherical structures. Male Wistar rats were divided into 5 groups, namely: Control, Vehicle, CSA, CSA + 2ME-Raw, and CSA + 2ME-Nano. CSA was injected daily at a SC dose of 20 mg/kg. Both 2ME-Raw and 2ME-Nano were given daily at oral doses of 5 mg/kg. Treatments continued for three successive weeks. 2ME-TPGS exerted significant protective effects against CSA nephrotoxicity. This was evidenced in ameliorating deterioration of renal functions, attenuation of pathological changes in kidney tissues, exerting significant anti-fibrotic, antioxidant, and anti-inflammatory effects together with significant anti-apoptotic effects. Western blot analyses showed both 2ME-Raw and 2ME-Nano significantly inhibited protein expression of TGF-β1 and phospho-ERK (p-ERK). It was observed that 2ME-TPGS, in almost all experiments, exerted superior protective effects as compared with 2ME-Raw. In conclusion, 2ME loaded in a TPGS nanocarrier possesses significant protective activities against CSA-induced kidney injury in rats. This is attributable to 2ME anti-fibrotic, antioxidant, anti-inflammatory, and anti-apoptotic activities which are mediated at least partly by inhibition of TGF-β1/p-ERK axis.

The potential protective effects of estradiol and 2-methoxyestradiol in ischemia reperfusion-induced kidney injury in ovariectomized female rats

AIMS

Investigating the impact of 17β estradiol (E2) and its endogenous non-hormonal metabolite 2-methoxyestradiol (2ME) on renal ischemia-reperfusion (RIR) induced kidney injury in ovariectomized (OVX) rats and the role of catechol-O-methyltransferase (COMT) in their effects.

MAIN METHODS

Eighty female rats were allocated into eight groups. Control group, Sham group, OVX group, OVX and RIR group, OVX + RIR + E2 group, OVX + RIR + 2ME group, OVX + RIR + E2 + Entacapone group and OVX + RIR + 2ME + Entacapone group, respectively. Twenty-four hours post RIR, creatinine (Cr) and blood urea nitrogen (BUN) were determined in serum, while malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), Glutathione (GSH), myeloperoxidase (MPO), as well as the expressions of COMT, hypoxia inducible factor-1α (HIF-1α) and tyrosine hydroxylase (TH) were assessed in the kidney tissues.

KEY FINDINGS

Serum Cr, BUN, MPO, as well as HIF-1α and TH expressions were significantly higher with concomitant decrease in COMT expression, SOD and CAT activities and GSH content observed in OVX and RIR group compared to sham group. E2 and 2ME treatment significantly ameliorated all parameters measured in OVX and RIR rats. On the other hand, Entacapone significantly decreased the effect of E2, with no effect on 2ME treatment.

SIGNIFICANCE

E2 ameliorates RIR-induced kidney injury and this effect is mediated, at least in part, via its COMT-mediated conversion to 2ME. Thus, 2ME by the virtue of its pleiotropic pharmacological effects can be used as a safe and effective treatment of RIR injury.

2-Methoxyestradiol Alleviates Neuroinflammation and Brain Edema in Early Brain Injury After Subarachnoid Hemorrhage in Rats

Objective

Numerous studies have shown that neuroinflammation and brain edema play an important role in early brain injury (EBI) after subarachnoid hemorrhage (SAH). 2-Methoxyestradiol (2-ME) has been shown to have anti-inflammatory and anti-angiogenic effects. This study aimed to investigate the effects of 2-ME on neuroinflammation and brain edema after SAH and its underlying mechanism of action.

Methods

Rats were used to produce an endovascular puncture model of SAH. 2-ME or the control agent was injected intraperitoneally 1 h after SAH induction. At 24 h after surgery, the neurological score, SAH grading, brain water content, and blood–brain barrier (BBB) permeability were examined. The microglial activation level in the rat brain tissue was determined using immunofluorescence staining, whereas the cell apoptosis in the rat brain tissue was assessed using terminal deoxynucleotidyl transferase dUTP nick-end labeling assay, the levels of Interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α were measured by enzyme linked immunosorbent assay, and the expression levels of ZO-1, occludin, hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), and matrix metallopeptidase (MMP)-9 in the rat brain tissue were determined using western blotting.

Results

Twenty-four hours after SAH, brain water content, BBB permeability, microglial activation, and cell apoptosis were significantly increased, whereas neurological function deteriorated significantly in rats. Treatment with 2-ME significantly decreased brain water content, BBB permeability, microglial cell activation, and cell apoptosis and improved neurological dysfunction in rats. Treatment with 2-ME reduced the expression levels of inflammatory factors (IL-1β, IL-6, and TNF-α), which were significantly elevated 24 h after SAH. Treatment with 2-ME alleviated the disruption of tight junction proteins (ZO-1 and occludin), which significantly decreased 24 h after SAH. To further determine the mechanism of this protective effect, we found that 2-ME inhibited the expression of HIF-1α, MMP-9, and VEGF, which was associated with the inflammatory response to EBI and BBB disruption after SAH.

Conclusion

2-ME alleviated neuroinflammation and brain edema as well as improved neurological deficits after SAH in rats. The neuroprotective effect of 2-ME on EBI after SAH in rats may be related to the inhibition of neuroinflammation and brain edema.

Alterations of Gut Microbiome and Serum Metabolome in Coronary Artery Disease Patients Complicated With Non-alcoholic Fatty Liver Disease Are Associated With Adverse Cardiovascular Outcomes

Rationale: Patients suffering from coronary artery disease (CAD) complicated with nonalcoholic fatty liver disease (NAFLD) present worse cardiovascular outcomes than CAD patients without NAFLD. The progression of CAD is recently reported to be associated with gut microbiota and microbe-derived metabolites. However, it remains unclear how the complication of NAFLD will affect gut microbiota and microbe-derived metabolites in CAD patients, and whether or not this interplay is related to the worse cardiovascular outcomes in CAD-NAFLD patients.

Methods: We performed 16S rRNA sequencing and serum metabolomic analysis in 27 CAD patients with NAFLD, 81 CAD patients without NAFLD, and 24 matched healthy volunteers. Predicted functional profiling was achieved using PICRUSt2. The occurrence of cardiovascular events was assessed by a follow-up study. The association of alterations in the gut microbiome and metabolome with adverse cardiovascular events and clinical indicators was revealed by Spearman correlation analysis.

Results: We discovered that the complication of NAFLD was associated with worse clinical outcomes in CAD patients and critical serum metabolome shifts. We identified 25 metabolite modules that were correlated with poor clinical outcome in CAD-NAFLD patients compared with non-NAFLD patients, represented by increased cardiac-toxic metabolites including prochloraz, brofaromine, aristolochic acid, triethanolamine, and reduced potentially beneficial metabolites including estradiol, chitotriose, palmitelaidic acid, and moxisylyte. In addition, the gut microbiome of individuals with CAD-NAFLD was changed and characterized by increased abundances of Oscillibacter ruminantium and Dialister invisus, and decreased abundances of Fusicatenibacter saccharivorans, Bacteroides ovatus and Prevotella copri. PICRUSt2 further confirmed an increase of potential pathogenic bacteria in CAD-NAFLD. Moreover, we found that variations of gut microbiota were critically correlated with changed circulating metabolites and clinical outcomes, which revealed that aberrant gut microbiota in CAD-NAFLD patients may sculpt a detrimental metabolome which results in adverse cardiovascular outcomes.

Conclusions: Our findings suggest that CAD patients complicated with NAFLD result in worse clinical outcomes possibly by modulating the features of the gut microbiota and circulating metabolites. We introduce “liver-gut microbiota-heart axis” as a possible mechanism underlying this interrelationship. Our study provides new insights on the contribution of gut microbiota heterogeneity to CAD-NAFLD progression and suggests novel strategies for disease therapy.

Protease-Activated Receptor-1 Antagonist Protects Against Lung Ischemia/Reperfusion Injury

Protease-activated receptor (PAR)-1 is a thrombin-activated receptor that plays an essential role in ischemia/reperfusion (IR)-induced acute inflammation. PAR-1 antagonists have been shown to alleviate injuries in various IR models. However, the effect of PAR-1 antagonists on IR-induced acute lung injury (ALI) has not yet been elucidated. This study aimed to investigate whether PAR-1 inhibition could attenuate lung IR injury. Lung IR was induced in an isolated perfused rat lung model. Male rats were treated with the specific PAR-1 antagonist SCH530348 (vorapaxar) or vehicle, followed by ischemia for 40 min and reperfusion for 60 min. To examine the role of PAR-1 and the mechanism of SCH530348 in lung IR injury, western blotting and immunohistochemical analysis of lung tissue were performed. In vitro, mouse lung epithelial cells (MLE-12) were treated with SCH530348 or vehicle and subjected to hypoxia-reoxygenation (HR). We found that SCH530348 decreased lung edema and neutrophil infiltration, attenuated thrombin production, reduced inflammatory factors, including cytokine-induced neutrophil chemoattractant-1, interleukin-6 and tumor necrosis factor-α, mitigated lung cell apoptosis, and downregulated the phosphoinositide 3-kinase (PI3K), nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways in IR-injured lungs. In addition, SCH530348 prevented HR-induced NF-κB activation and inflammatory chemokine production in MLE12 cells. Our results demonstrate that SCH530348 exerts protective effects by blocking PAR-1 expression and modulating the downstream PI3K, NF-κB and MAPK pathways. These findings indicate that the PAR-1 antagonist protects against IR-induced ALI and is a potential therapeutic candidate for lung protection following IR injury.