The clinical significance of neutrophil gelatinase-associated lipocalin in ischemic stroke patients with acute kidney injury

Improving stroke prognosis by TLR4 KO to enhance N2 neutrophil infiltration and reduce M1 macrophage polarization

Cerebral ischemic stroke remains a leading cause of mortality and morbidity worldwide. Toll-like receptor 4 (TLR4) has been implicated in neuroinflammatory responses poststroke, particularly in the infiltration of immune cells and polarization of macrophages. This study aimed to elucidate the impact of TLR4 deficiency on neutrophil infiltration and subsequent macrophage polarization after middle cerebral artery occlusion (MCAO), exploring its role in stroke prognosis. The objective was to investigate how TLR4 deficiency influences neutrophil behavior poststroke, its role in macrophage polarization, and its impact on stroke prognosis using murine models. Wild-type and TLR4-deficient adult male mice underwent MCAO induction, followed by various analyses, including flow cytometry to assess immune cell populations, bone marrow transplantation experiments to evaluate TLR4-deficient neutrophil behaviors, and enzyme-linked immunosorbent assay and Western blot analysis for cytokine and protein expression profiling. Neurobehavioral tests and infarct volume analysis were performed to assess the functional and anatomical prognosis poststroke. TLR4-deficient mice exhibited reduced infarct volumes, increased neutrophil infiltration, and reduced M1-type macrophage polarization post-MCAO compared to wild-type mice. Moreover, the depletion of neutrophils reversed the neuroprotective effects observed in TLR4-deficient mice, suggesting the involvement of neutrophils in mediating TLR4's protective role. Additionally, N1-type neutrophils were found to promote M1 macrophage polarization via neutrophil gelatinase-associated lipocalin (NGAL) secretion, a process blocked by TLR4 deficiency. The study underscores the protective role of TLR4 deficiency in ischemic stroke, delineating its association with increased N2-type neutrophil infiltration, diminished M1 macrophage polarization, and reduced neuroinflammatory responses. Understanding the interplay between TLR4, neutrophils, and macrophages sheds light on potential therapeutic targets for stroke management, highlighting TLR4 as a promising avenue for intervention in stroke-associated neuroinflammation and tissue damage.

Association of beta-2-microglobulin, cystatin C and lipocalin-2 with stroke risk in the general Chinese population

INTRODUCTION

Beta-2-microglobulin (B2M), cystatin C and lipocalin-2 (LCN-2) are established renal biomarkers, yet their roles in stroke have not been fully evaluated. We aimed to investigate the relationship of B2M, cystatin C, and LCN-2 with stroke risk in a general Chinese population.

METHODS

We used ordinal regression to study the relationship between serum B2M, cystatin C, and LCN-2 with stroke risk in 1060 participants (mean age 45.4 ± 10.8 years, 46% male) from the Shenzhen-Hong Kong United Network on Cardiovascular Disease (SHUN-CVD) study. Stroke risk was classified into low-risk, middle-risk and high-risk groups according to the China National Stroke Screening Survey criteria. Serum biomarker levels were measured using immunoturbidimetric assays. Participants with valid data on serum biomarker levels and stroke risk were included in the analysis.

RESULTS

The number of participants in the low-risk, middle-risk and high-risk stroke risk groups were 663, 143 and 254 respectively. Elevated serum B2M, cystatin C, and LCN-2 levels were associated with being male, overweight/obesity, hypertension, alcohol consumption and smoking. Serum B2M, cystatin C and LCN-2 levels were significantly associated with stroke risk in the overall population (B2M: β = 0.595, p < .001; cystatin C: β = 3.718, p < .001; LCN-2: β = 0.564, p < .001) after adjustment for age.

CONCLUSION

Elevated serum B2M, cystatin C and LCN-2 levels are associated with stroke risk. They may be novel biomarkers for clinicians to assess stroke risk.Key messagesSerum beta-2-microglobulin, cystatin C and lipocalin-2 levels are significantly associated with stroke risk.Beta-2-microglobulin, cystatin C and lipocalin-2 may serve as useful biomarkers for stroke risk stratification in the general population.

A novel risk model based on white blood cell-related biomarkers for acute kidney injury prediction in patients with ischemic stroke admitted to the intensive care unit

Background

Conventional systemic inflammatory biomarkers could predict prognosis in patients with ischemic stroke (IS) admitted to the intensive care unit (ICU). Acute kidney injury (AKI) is common in patients with IS admitted to ICU, but few studies have used systemic inflammatory biomarkers to predict AKI in critically ill patients with IS. This study aimed to establish a risk model based on white blood cell (WBC)-related biomarkers to predict AKI in critically ill patients with IS.

Methods

Data were extracted from the Medical Information Mart for Intensive Care-IV (MIMIC-IV) for a training cohort, and data were extracted from the Medical Information Mart for eICU Collaborative Research Database (eICU-CRD) for a validation cohort. Logistic regression analysis was used to determine the significant predictors of WBC-related biomarkers on AKI prediction, and a risk model was established based on those significant indicators in multivariate logistic regression. The receiver operating characteristics (ROC) curve was utilized to obtain the best cut-off value of the risk model. The Kaplan-Meier curve was used to evaluate the prognosis-predictive ability of the risk model.

Results

The overall incidence of AKI was 28.4% in the training cohort and 33.2% in the validation cohort. WBC to lymphocyte ratio (WLR), WBC to basophils ratio (WBR), WBC to hemoglobin ratio (WHR), and neutrophil to lymphocyte ratio (NLR) could independently predict AKI, and a novel risk model was established based on WLR, WBR, WHR, and NLR. This risk model depicted good prediction performance both in AKI and other clinical outcomes including hemorrhage, persistent AKI, AKI progression, ICU mortality, and in-hospital mortality both in the training set and in the validation set.

Conclusion

A risk model based on WBC-related indicators exhibited good AKI prediction performance in critically ill patients with IS which could provide a risk stratification tool for clinicians in the ICU.

Analysis of the diagnostic capabilities of urinary neutrophil gelatinase-associated lipocalin and serum procalcitonin for acute kidney injury at the early stage of critical care intensive care unit admission

BACKGROUND

Acute kidney injury (AKI) is a disease that negatively affects patient prognosis and requires early diagnosis and treatment. Biomarkers that predict AKI are needed for early diagnosis of this disease.

METHODS

We compared the AKI group and the non-AKI group in patients who were admitted to our critical care intensive care unit (ICU) and conducted a comparative study focusing on urinary neutrophil gelatinase-associated lipocalin (U-NGAL) and serum procalcitonin (PCT).

RESULTS

Seventy-one out of 106 ICU inpatients were diagnosed with AKI in accordance with the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Among the patients who were diagnosed with AKI stages 1 to 3, 94.4% of all patients reached the maximum stage by day 5 after admission. Comparing the non-AKI group and AKI stage 1 to 3 on days 1 to 3 after admission, U-NGAL and PCT levels in the stage 3 group were significantly higher than those in the non-AKI group. Additionally, in receiver operating characteristic curve (ROC) analysis on days 1-3 after admission, U-NGAL and PCT levels can be used as biomarkers for the diagnosis of AKI, and in particular, AKI stage 3 can be predicted and diagnosed with high accuracy. U-NGAL and PCT levels were also significantly higher in AKI due to sepsis and acute pancreatitis and due to sepsis, respectively.

CONCLUSIONS

Measuring U-NGAL and PCT levels as biomarkers for AKI may further improve the accuracy of AKI diagnosis in critical care ICU.

Oridonin Alleviates IRI-Induced Kidney Injury by Inhibiting Inflammatory Response of Macrophages via AKT-Related Pathways

BACKGROUND Acute kidney injury (AKI) is one of the most common complications in clinic, but there is still no effective treatment. Oridonin, extracted from Rabdosia rubescens, has been identified to promote inhibitory effects on tumor, inflammatory and fibrosis by previous study. This study aimed to assess the kidney-protective role of Oridonin in AKI and the underlying mechanism by which Oridonin improves AKI in vivo and inhibits inflammation in LPS-induced bone marrow-derived macrophages (BMDM) in vitro. MATERIAL AND METHODS SPF C57BL/6J male mice (8 - 10 weeks old, body weight 20 - 25 g) were divided into 3 groups - sham group, AKI group, and Oridonin-treated AKI group - with 6 mice in each group. In the in vitro study, LPS-induced inflammatory BMDM cells were treated with Oridonin and agonist of AKT. The expression and secretion levels of inflammation-related indicators and AKT-related signaling molecules were detected by real-time PCR, ELISA, Western blot, and immunofluorescence. Also, various methods are used to assess renal function and pathological changes. RESULTS The results showed that Oridonin treatment significantly improved the serum creatinine and BUN levels in AKI mice. Interestingly, treatment with Oridonin also resulted in decreased the infiltration of macrophages in renal tissues of AKI mice, which was associated with decreased expression and activation of AKT and its related signaling pathways, such as NF-kappaB and STAT3, suggesting that Oridonin attenuates AKI kidney injury via a mechanism associated with reducing the inflammatory response of macrophages in the AKI kidney. This was investigated in vitro in macrophages, and the results showed that Oridonin reduced the LPS-stimulated inflammatory response in macrophages. Mechanistically, the addition of Oridonin reversed LPS-induced downregulation of AKT, NF-kappaB, and STAT3 expression and inflammatory response in macrophages, suggesting that Oridonin has a protective role, via the AKT-related signaling pathways, in reducing the inflammatory response of macrophages in AKI mice. This was further confirmed by adding agonist of AKT of IGF-1 to block the inhibitory effect of Oridonin on inflammatory response in vitro. CONCLUSIONS Oridonin ameliorates AKI kidney injuries by suppressing AKT-mediated inflammatory response of macrophages.

The clinical significance of neutrophil gelatinase-associated lipocalin in ischemic stroke patients with acute kidney injury

BACKGROUND

Acute kidney injury (AKI) has become a common complication of acute ischemic stroke (AIS) and may have a significant impact on the clinical outcomes. Neutrophil gelatinase-associated lipocalin (NGAL), an acute phase protein, has been identified as a novel biomarker for acute kidney impairment. Here, we studied the early expression of NGAL in AIS patients with AKI and its clinic value in predicting and diagnosis of AKI after stroke.

METHODS

A total of 205 subjects diagnosed as first-ever AIS were recruited in this study, including 40 AIS with AKI and 165 AIS without AKI defined using the KDIGO guidelines. The serum and urine levels of NGAL were measured with ELISA. To evaluate the clinic value of NGAL, we also detected creatinine, urea nitrogen and cystatin C and microalbumin (mALB) in serum or urine using chemiluminescence or immunoturbidimetry method, and then the receiver operating characteristic (ROC) curve and correlation was analyzed. The severity of AIS patients was evaluated based on the National Institutes of Health Stroke Scale (NIHSS) score.

RESULTS

The serum and urine NGAL levels were significantly increased in AIS patients with AKI, and line regression analysis indicated that there was a positive correlation between the serum NGAL and creatinine level in AIS patients accompanied AKI. Additionally, the concentration of serum NGAL in AIS patients with AKI increased with the severity of stroke.

CONCLUSION

The increased serum NGAL may be used as a valuable complementary marker for the diagnoses and prediction of AKI in the early stage of AIS patients.