Acute Kidney Injury Induces Innate Immune Response and Neutrophil Activation in the Lung

Garlic oil supplementation blocks inflammatory pyroptosis-related acute lung injury by suppressing the NF-κB/NLRP3 signaling pathway via H2S generation

Acute lung injury (ALI) is a major cause of acute respiratory failure with a high morbidity and mortality rate, and effective therapeutic strategies for ALI remain limited. Inflammatory response is considered crucial for the pathogenesis of ALI. Garlic, a globally used cooking spice, reportedly exhibits excellent anti-inflammatory bioactivity. However, protective effects of garlic against ALI have never been reported. This study aimed to investigate the protective effects of garlic oil (GO) supplementation on lipopolysaccharide (LPS)-induced ALI models. Hematoxylin and eosin staining, pathology scores, lung myeloperoxidase (MPO) activity measurement, lung wet/dry (W/D) ratio detection, and bronchoalveolar lavage fluid (BALF) analysis were performed to investigate ALI histopathology. Real-time polymerase chain reaction, western blotting, and enzyme-linked immunosorbent assay were conducted to evaluate the expression levels of inflammatory factors, nuclear factor-κB (NF-κB), NLRP3, pyroptosis-related proteins, and H2S-producing enzymes. GO attenuated LPS-induced pulmonary pathological changes, lung W/D ratio, MPO activity, and inflammatory cytokines in the lungs and BALF. Additionally, GO suppressed LPS-induced NF-κB activation, NLRP3 inflammasome expression, and inflammatory-related pyroptosis. Mechanistically, GO promoted increased H2S production in lung tissues by enhancing the conversion of GO-rich polysulfide compounds or by increasing the expression of H2S-producing enzymes in vivo. Inhibition of endogenous or exogenous H2S production reversed the protective effects of GO on ALI and eliminated the inhibitory effects of GO on NF-κB, NLRP3, and pyroptotic signaling pathways. Overall, these findings indicate that GO has a critical anti-inflammatory effect and protects against LPS-induced ALI by suppressing the NF-κB/NLRP3 signaling pathway via H2S generation.

MicroRNA-598 inhibition ameliorates LPS-induced acute lung injury in mice through upregulating Ebf1 expression

Acute lung injury is a critical acute respiratory distress syndrome (ARDS) with high morbidity and mortality. MicroRNAs (miRNAs) have been demonstrated to play important roles regulating acute lung injury development. In this study, we found that the expression of miR-598 was significantly upregulated in the lung tissues of mice with lipopolysaccharide (LPS)-induced acute lung injury. Both loss-of-function and gain-of-function studies were performed to evaluate the function of miR-598 in acute lung injury. The results showed that inhibition of miR-598 attenuated inflammatory response, oxidative stress, and lung injury in mice treated with LPS, while overexpression of miR-598 exacerbated the LPS-induced acute lung injury. Mechanistically, transcription factor Early B-cell Factor-1 (Ebf1) was predicted and validated as a downstream target of miR-598. Overexpression of Ebf1 attenuated LPS-induced production of inflammatory cytokine TNF-α and IL-6, ameliorated LPS-induced oxidative stress, promoted proliferation, and inhibited apoptosis in murine lung epithelial-15 (MLE-15) cells. Moreover, we demonstrated that Ebf1 knockdown abolished the protective effect of miR-598 inhibition in LPS-treated MLE-15 cells. In summary, miR-598 inhibition ameliorates LPS-induced acute lung injury in mice through upregulating Ebf1 expression, which might provide potential therapeutic treatment for acute lung injury.

Pterostilbene pre-treatment reduces LPS-induced acute lung injury through activating NR4A1

CONTEXT

Pterostilbene (PTE), a common polyphenol compound, exerts an anti-inflammatory effect in many diseases, including acute lung injury (ALI).

OBJECTIVE

This study explores the potential mechanism of PTE pre-treatment against lipopolysaccharide (LPS)-induced ALI.

MATERIALS AND METHODS

Sixty Sprague-Dawley rats were divided into control, ALI, 10 mg/kg PTE + LPS, 20 mg/kg PTE + LPS, and 40 mg/kg PTE + LPS groups. At 24 h before LPS instillation, PTE was administered orally. At 2 h before LPS instillation, PTE was again administered orally. After 24 h of LPS treatment, the rats were euthanized. The levels of inflammatory cells and inflammatory factors in the bronchoalveolar lavage fluid (BALF), the expression of nuclear receptor subfamily 4 group A member 1 (NR4A1), and the nuclear factor (NF)-κB pathway-related protein levels were detected. NR4A1 agonist was used to further investigate the mechanism of PTE pre-treatment.

RESULTS

After PTE pre-treatment, the LPS induced inflammation was controlled and the survival rate was increased to 100% from 70% after LPS treatment 24 h. For lung injury score, it decreased to 1.5 from 3.5 after treating 40 mg/kg PTE. Compared with the control group, the expression of NR4A1 in the ALI group was decreased by 20-40%. However, the 40 mg/kg PTE pre-treatment increased the NR4A1 expression by 20-40% in the lung tissue. The results obtained with pre-treatment NR4A1 agonist were similar to those obtained by pre-treatment 40 mg/kg PTE.

CONCLUSIONS

PTE pre-treatment might represent an appropriate therapeutic target and strategy for preventing ALI induced by LPS.

Renoprotective Effects of Luteolin: Therapeutic Potential for COVID-19-Associated Acute Kidney Injuries

Acute kidney injury (AKI) has been increasingly reported in critically-ill COVID-19 patients. Moreover, there was significant positive correlation between COVID-19 deaths and renal disorders in hospitalized COVID-19 patients with underlying comorbidities who required renal replacement therapy. It has suggested that death in COVID-19 patients with AKI is 3-fold higher than in COVID-19 patients without AKI. The pathophysiology of COVID-19-associated AKI could be attributed to unspecific mechanisms, as well as COVID-19-specific mechanisms such as direct cellular injury, an imbalanced renin-angiotensin-aldosterone system, pro-inflammatory cytokines elicited by the viral infection and thrombotic events. To date, there is no specific treatment for COVID-19 and its associated AKI. Luteolin is a natural compound with multiple pharmacological activities, including anticoronavirus, as well as renoprotective activities against kidney injury induced by sepsis, renal ischemia and diverse nephrotoxic agents. Therefore, in this review, we mechanistically discuss the anti-SARS-CoV-2 and renoprotective activities of luteolin, which highlight its therapeutic potential in COVID-19-AKI patients.

Propofol Reduces Renal Ischemia Reperfusion-mediated Necroptosis by Up-regulation of SIRT1 in Rats

Propofol (Pro) is well known to regulate the asleep-awake-asleep technique. Increasing indication recommends that Pro also has promising properties such as anti-oxidant and anti-inflammation belongings in several disease models. It has been described that Pro has beneficial properties against renal ischemia/reperfusion (rI/R)-mediated acute lung injury (ALI). Nevertheless, pathogenesis underlying the beneficial action of Pro on the remote ALI mediated by rI/R remains unwell unstated. In this research, we displayed that Pro administration remarkably inhibits rI/R-mediated pro-inflammatory cytokines production. Increased levels of oxidative stress were mainly decreased by Pro. Pro administration ameliorated apoptosis-related caspase-3 activation. Furthermore, the levels of crucial necroptosis-associated protein were reduced by Pro. Sirtuin 1 (SIRT1) inhibitor attenuated the aforementioned changes of Pro. In conclusion, these results propose that Pro attenuates rI/R-induced inflammation, oxidative stress, apoptosis, and necroptosis by up-regulation of SIRT1 in rats. Our findings disclose an original pathogenesis underlying the beneficial effect of Pro against rI/R-mediated ALI and reinforce the knowledge that Pro might be a hopeful beneficial agent for the rI/R-mediated ALI.

Prognostic Prediction Using the Clinical Data and Ultrasomics-Based Model in Acute Respiratory Distress Syndrome (ARDS) Combined with Acute Kidney Injury (AKI)

OBJECTIVE

A model was constructed based on clinical and ultrasomics features to predict the prognosis of patients in the respiratory intensive unit (RICU) who had acute respiratory distress syndrome (ARDS) combined with acute kidney injury (AKI). AKI ensues after ARDS in RICU ordinarily. The prognostic prediction tool was further developed on this basis.

METHODS

We collected clinical and ultrasonic data from 145 patients who had ARDS combined with AKI and received continuous renal replacement therapy (CRRT) in the RICU of Xiangyang Hospital of Traditional Chinese Medicine from March 2016 to November 2019. The patients were divided into the survival group (n = 51) and the death group (n = 94), depending on the treatment outcome. The training set (n = 102) and the testing set (n = 43) were established based on patient data. The clinical and ultrasomics features and the CRRT parameters were compared between the two groups. The influence factors of death were analyzed by logistic regression, and four predictive models were established. The predictive performance of 4 models was compared using the R Software 4.1.3. The decision curve analysis graphs were drawn using the R language to determine the net benefit of each.

RESULT

Univariate analysis was conducted in the training set. The following risk factors for poor prognosis were identified: age, concurrent cancers, sequential organ failure assessment score (SOFA), number of organ dysfunctions, positive cumulative fluid balance at 72 h, time from ICU admission to CRRT, mean arterial pressure, oxygenation index, and gray-level size zone matrix, GLSZM (SumEntropy.239/SmallDependenceHighGrayLevelEmphasis.314/Maximum.327/Variance.338) (P < 0.05). Four models were built based on the above factors: clinical model, CRRT model, ultrasomics-based model, and combination model. Comparison using the MedCalc software indicated that the best predictive performance achieved with the combination model. The decision curve analysis also suggested that the combination model had the highest net benefit. Similar results were reported after validation on the testing set.

CONCLUSION

The prognosis of ARDS patients combined with AKI is usually poor. The combination model based on clinical and ultrasomics features had the highest predictive performance. This model can be used to improve the clinical outcome and prognosis.

Systemic Human Neutrophil Lipocalin Associates with Severe Acute Kidney Injury in SARS-CoV-2 Pneumonia

Neutrophils have been suggested mediators of organ dysfunction in COVID-19. The current study investigated if systemic neutrophil activity, estimated by human neutrophil lipocalin (HNL) concentration in peripheral blood, is associated with acute kidney injury (AKI) development. A total of 103 adult patients admitted to intensive care, with PCR-confirmed SARS-CoV-2 infection, were prospectively included (Clinical Trials ID: NCT04316884). HNL was analyzed in plasma (P-HNL Dimer) and in whole blood (B-HNL). The latter after ex vivo activation with N-formyl-methionine-leucine-phenylalanine. All patients developed respiratory dysfunction and 62 (60%) were treated with invasive ventilation. Sixty-seven patients (65%) developed AKI, 18 (17%) progressed to AKI stage 3, and 14 (14%) were treated with continuous renal replacement therapy (CRRT). P-HNL Dimer was higher in patients with invasive ventilation, vasopressors, AKI, AKI stage 3, dialysis, and 30-day mortality (p < 0.001–0.046). B-HNL performed similarly with the exception of mild AKI and mortality (p < 0.001–0.004). The cohort was dichotomized by ROC estimated cutoff concentrations of 13.2 µg/L and 190 µg/L for P-HNL Dimer and B-HNL respectively. Increased cumulative risks for AKI, AKI stage 3, and death were observed if above the P-HNL cutoff and for AKI stage 3 if above the B-HNL cutoff. The relative risk of developing AKI stage 3 was nine and 39 times greater if above the cutoffs in plasma and whole blood, respectively, for CRRT eight times greater for both. In conclusion, systemically elevated neutrophil lipocalin, interpreted as increased neutrophil activity, was shown to be associated with an increased risk of severe AKI, renal replacement therapy, and mortality in COVID-19 patients with respiratory failure.