The relationship between a series of inflammatory markers on the risk of heart failure in different gender groups: Analysis from NHANES 2015-2018

BACKGROUND

A better understanding of the level-grade inflammation for the development and worsening of heart failure (HF) in different gender groups is an unmet need. We performed an updated analysis on the impact of a series of systemic inflammation markers on HF.

METHODS

This compensatory cross-sectional study enrolled participants from the National Health and Nutrition Examination Survey (NHANES) 2015-2018. HF was based on the self-reported questions. Univariate and multivariate logistic regression were used to investigate the association between systemic immune-inflammation index (SII), high sensitivity C-reactive protein (hs-CRP), lymphocyte-to-monocyte ratio (LMR), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and HF. For patients of different genders, P for trend was used to analyze potential linear trend relationships and the restricted cubic splines (RCS) were used to describe non-linear relationships. The additive interaction was evaluated by the relative excess risk due to interaction (RERI), attributable proportion (AP), and the synergy index (SI). The multiplicative interaction was evaluated by odds ratio (OR) and 95% confidence interval (CI) of product-term.

RESULTS

A total of 5,830 participants from the NHANES database were divided into two groups: the HF group (n = 210) and the non-HF group (n = 5620). After gender stratification, hs-CRP (OR: 1.01, 95% CI: 1.00-1.03), SII (OR: 1.00, 95% CI: 1.00-1.01), NLR (OR: 1.22, 95% CI: 1.11-1.35) and LMR (OR: 0.79, 95% CI: 0.65-0.93) were independent meaningful factors for HF in males, there was no non-linear relationship between the three factors (SII, NLR, hs-CRP, all P for non-linear > 0.05) and the prevalence of HF, but we detected a non-linear relationship between LMR and the prevalence of HF in males (P for non-linear < 0.05). An additive interaction of hs-CRP and NLR on the risk of HF in males (RERI (OR): 0.67, 95% CI: 0.12-1.34; AP (OR): 0.14, 95% CI: 0.02-0.24; SI (OR): 1.22, 95% CI: 1.03-1.44).

CONCLUSIONS

In summary, hs-CRP, NLR, and LMR are superior meaningful markers for HF in males. SII may be a meaningful systemic inflammation warning marker for HF, which needs to be discriminated against with caution. Only detected a non-linear relationship between LMR and the prevalence of HF in males. NLR and hs-CRP may have an additive interaction in the prevalence of male HF patients. The outcome compensated for previous studies that still needed more studies for validation.

Exploring the relations of NLR, hsCRP and MCP-1 with type 2 diabetic kidney disease: a cross-sectional study

Type 2 diabetic kidney disease (T2DKD) is a common microvascular complication of type 2 diabetes mellitus (T2DM), and its incidence is significantly increasing. Microinflammation plays an important role in the development of T2DKD. Based on this, this study investigated the value of inflammatory markers including neutrophil-lymphocyte ratio (NLR), high-sensitivity C-reactive protein (hs-CRP), monocyte chemoattractant protein-1 (MCP-1) in the prediction of T2DKD. This was a cross-sectional survey study. A total of 90 patients with T2DM, who were hospitalized in the nephrology and endocrinology departments of the First Teaching Hospital of Tianjin University of Traditional Chinese Medicine from June 2021 to January 2022, were included and divided into three groups (A1, A2, A3) according to the urinary albumin-to-creatinine ratio (UACR). Observe and compare the basic information, clinical and laboratory data, and the inflammatory markers NLR, hs-CRP, MCP-1. Results revealed that high levels of NLR (OR = 6.562, 95% CI 2.060-20.902, P = 0.001) and MCP-1 (OR = 1.060, 95% CI 1.026-1.095, P < 0.001) were risk factors in the development of T2DKD. Receiver operating characteristic curve analysis showed that the area under curve of NLR and MCP-1 in diagnosing T2DKD were 0.760 (95% CI 0.6577-0.863, P < 0.001) and 0.862 (95% CI 0.7787-0.937, P < 0.001). Therefore, the inflammatory markers NLR and MCP-1 are risk factors affecting the development of T2DKD, which of clinical value may be used as novel markers of T2DKD.

Neutrophil-Lymphocyte Ratio and Lymphocyte-Monocyte Ratio correlate with Chronic Prosthetic Joint Infection but are not useful markers for diagnosis

PURPOSE

To investigate reported correlations between Neutrophil-to-Lymphocyte (NLR) and Lymphocyte-to-Monocyte (LMR) ratios and their value in diagnosis of chronic prosthetic joint infection (PJI) in a large cohort of patients from a single specialist hospital.

METHODS

Diagnostic aspirations of 362 patients under investigation for PJI were identified. Of the included patients 185 patients received a final diagnosis of PJI and 177 were classed as aseptic. Established criteria (ICM 2018) were employed to define PJI. Included in the analysis are differential white cell counts, C-Reactive Protein (CRP), Synovial Leukocyte Count, Synovial Alpha-defensin ELISA and Synovial Leukocyte esterase activity. Receiver-operator characteristic (ROC) curves were calculated for each of the available diagnostic tests together with the corresponding area under the curve values (AUC). Youden's index was utilized to identify the optimal diagnostic threshold point for the NLR and LMR. Other diagnostic tests were evaluated as per the threshold values previously defined in the literature and specified in the ICM criteria.

RESULTS

Using Youden's Index to identify the optimal NLR cut-off within our cohort we established a value of 2.93. This yielded a sensitivity of 0.60 and specificity of 0.64. The area under the curve (AUC) of a receiving operator characteristics (ROC) curve was 0.625. Regarding the LMR the results demonstrate similar findings; a positive correlation with a diagnosis of infection but poor sensitivity and specificity. The AUC for LMR was 0.633 and was not superior to NLR (P = 0.753).

CONCLUSIONS

There is a significant correlation between higher Neutrophil-Lymphocyte and Lymphocyte-Monocyte ratios, and a diagnosis of PJI. The sensitivity and specificity of this calculation is poor and the does not add value to the diagnostic algorithm for PJI.

LEVEL OF EVIDENCE

Level III Retrospective Cohort analysis.

Exploring the diagnostic and prognostic value of the C-reactive protein/lymphocyte ratio for dilated cardiomyopathy based on a real-world study

To determine the risk factors for dilated cardiomyopathy (DCM) and construct a risk model for predicting HF in patients with DCM, We enrolled a total of 2122 patients, excluding those who did not meet the requirements. A total of 913 patients were included in the analysis (611 males and 302 females) from October 2012 to May 2020, and data on demographic characteristics, blood biochemical markers, and cardiac ultrasound results were collected. Patients were strictly screened for DCM based on the diagnostic criteria. First, these patients were evaluated using propensity score matching (PSM). Next, unconditional logistic regression was used to assess HF risk. Furthermore, receiver operating characteristic (ROC) curve analysis was conducted to determine diagnostic efficiency, and a nomogram was developed to predict HF. Finally, the Kaplan‒Meier survival curve was plotted. Of the initial 2122 patients, the ejection fraction (EF) in males was worse. We included 913 patients after the final DCM diagnosis. The results showed that the levels of NT-proBNP, WBC, PLT, neutrophils, lymphocytes, eosinophils, and IL-6, C-reactive protein (CRP) and the neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), and CRP/lymphocyte ratio (CLR) were higher in males than in females (P < 0.001-0.009). The nomogram showed that factors such as sex, WBC, neutrophils, PLR, and CLR could predict the risk of worsening cardiac function in patients with DCM before and after PSM (P < 0.05). The ROC curve showed that CLR with an 85.6% area demonstrated higher diagnostic efficacy than the NLR (77.0%) and PLR (76.6%, P < 0.05). Survival analysis showed a higher mortality risk in females with higher CLR levels (P < 0.001-0.009). However, high CLR levels indicated a higher mortality risk (P < 0.001) compared to sex. Male EF is lower in DCM patients. CLR could predict the risk of declined cardiac function in patients with DCM. The mortality in females with higher CLR levels was highest; however, the exact mechanism should be investigated.

Clinical value of neutrophil-to-lymphocyte ratio and prognostic nutritional index on prediction of occurrence and development of diabetic foot-induced sepsis

Background

Diabetic foot-induced sepsis is a serious complication associated with increased disability and mortality in hospitalized patients. Early prediction of admission and detection effectively improve treatment options and prevent further deterioration. This study aims to evaluate the clinical value of the neutrophil-to-lymphocyte ratio (NLR) and prognostic nutritional index (PNI) to predict the risk of sepsis in patients with diabetic foot ulcers (DFU).

Methods

Retrospective analysis was performed on 216 patients who were admitted to the Fujian Medical University Union Hospital between January 2015 and December 2022. Patients with DFU were divided into the non-sepsis (n = 166) and the DFU-induced sepsis (n = 50) groups. The independent factors of DFU-induced sepsis were determined by univariate and multivariate logistic regression analyses. A receiver operating characteristic (ROC) curve was performed to compare the area under the curves (AUC) of PNI and NLR.

Results

Multivariate logistic regression analysis revealed that the PNI, NLR, international normalized ratio (INR), thrombin time (PT), and C-reactive protein (CRP) were independent prognostic factors for DFU-induced sepsis. After adjusting for potential confounders, the adjusted odds ratios of NLR for DFU-induced sepsis were 1.121 (1.072-1.172), 1.132 (1.077-1.189), and 1.080 (1.022-1.142), while those of PNI were 0.912 (0.873-0.953), 0.902 (0.856-0.950), and 1.004 (1.001-1.006). Moreover, the AUC of NLR was significantly greater than that of CRP (0.790, 95% CI: 0.689-0.891, p < 0.001 vs. 0.780, 95% CI: 0.686-0.873, p < 0.001).

Conclusion

NLR and PNI have been regarded as readily and independently predictive markers in patients with DFU-induced sepsis. NLR is critical for the early detection and effective treatment of DFU-induced sepsis and is superior to CRP.

Correlation between C-reactive protein and the inflammatory ratios in acute schizophrenia inpatients: are they associated?

C-reactive protein (CRP) and inflammatory ratios have been proposed to study immune dysregulation in schizophrenia. Nevertheless, links between CRP and inflammatory ratios in acute SCZ inpatients have been understudied. This study investigated the relationship between CRP and inflammatory ratios (Neutrophil-Lymphocyte Ratio [NRL], Platelet-Lymphocyte Ratio [PLR], Monocyte-Lymphocyte ratio [MLR] and Basophil-Lymphocyte Ratio [BLR]) in a total of 698 acute SCZ inpatients; and analysed how this relationship is affected by sex and type of episode. CRP correlated with NLR (rs = 0.338, p < 0.001), PLR (rs = 0.271, p < 0.001) and MLR (rs = 0.148, p < 0.001) but not with BLR (rs = 0.059, p = 0.121). Multiple lineal regression analysis showed that high levels of NLR, MLR and PLR but not BLR were independently associated with high CRP levels. No sex-related variations were found. Significant associations were maintained for NLR and MLR in first-episode and multiepisode SCZ, although the strength of the association was stronger in multiepisode SCZ. Again, no sex-related differences were found in these associations. In conclusion, inflammatory ratios were low to moderately associated with CRP in acute SCZ inpatients. NLR and multiepisode SCZ showed the highest associations with CRP. Future studies should consider inflammatory ratios not as a substitute for CRP but as a complementary biomarker.

Engineered Artificial Human Neutrophils Exhibit Mature Functional Performance

Neutrophils, a key innate immune component, are powerful effector leukocytes for mediating opposing effects on tumor progression and ameliorating pathogen infections. However, their short lifespan and complex purification process have limited neutrophil clinical applications. Here we combined genetic engineering technology with a nanodrug system to construct artificial neutrophils that display functions similar to those of native neutrophils. K562 and HL60 human leukemia cells were engineered to express the human G protein-coupled receptor hM4Di. Compared to the parental cells, engineered hM4Di-K562 and hM4Di-HL60 cells exhibited excellent chemotaxis ability towards clozapine-N-oxide (CNO) and superior bacteria phagocytic behavior, resembling native neutrophils. The antibacterial ability of the hM4Di-K562 cells was further enhanced by loading them with the glycopeptide vancomycin via mesoporous silica nanoparticles (Nano@Van). Our proposed artificial cell engineering platform provides a new avenue to investigate the physiological properties of neutrophils.

Short-term impacts of air pollution on the platelet-lymphocyte ratio and neutrophil-lymphocyte ratio among urban adults in China

The short-term impacts of urban air pollution on the platelet-lymphocyte ratio (PLR) and neutrophil-lymphocyte ratio (NLR) remain obscure. In this study, we included 3487 urban adults from the Wuhan-Zhuhai cohort. Individual inhalation exposure to air pollutants was estimated by combining participants' daily breath volume and ambient concentrations of six air pollutants (including fine particulate matter (PM_2.5), inhalable particulate matter (PM₁₀), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), carbon monoxide (CO) and ozone (O₃)). The cumulative impacts were assessed by applying lag structures of up to 7 days before the survey date. Associations of air pollutants with PLR and NLR were assessed using a linear mixed model and Bayesian kernel machine regression (BKMR) model. We found that PLR was negatively related to PM_2.5 (lag02-lag06), PM₁₀ (lag02-lag07), NO₂ (lag02-lag07), and SO₂ (lag03-lag05) and NLR was negatively related to PM₁₀ (lag05 and lag07). In the BKMR model, a negative joint association between the six-air-pollutant mixture and PLR and NLR was observed, whereas PM₁₀ and NO₂ appeared to be more important than the other pollutants in the mixture. The negative impact of air pollutants was stronger in males, participants with lower body mass index (< 24 kg/m²), those cooking meals at home, drinkers, and non-exercisers. In conclusion, short-term exposure to air pollutants is significantly related to PLR and NLR in peripheral blood. PLR and NLR may provide new insight into the molecular mechanism underlying the adverse health impact of air pollutants.

The Olfactomedin-4-Defined Human Neutrophil Subsets Differ in Proteomic Profile in Healthy Individuals and Patients with Septic Shock

The specific granule glycoprotein olfactomedin-4 (Olfm4) marks a subset (1-70%) of human neutrophils and the Olfm4-high (Olfm4-H) proportion has been found to correlate with septic shock severity. The aim of this study was to decipher proteomic differences between the subsets in healthy individuals, hypothesizing that Olfm4-H neutrophils have a proteomic profile distinct from that of Olfm4 low (Olfm4-L) neutrophils. We then extended the investigation to septic shock. A novel protocol for the preparation of fixed, antibody-stained, and sorted neutrophils for LC-MS/MS was developed. In healthy individuals, 39 proteins showed increased abundance in Olfm4-H, including the small GTPases Rab3d and Rab11a. In Olfm4-L, 52 proteins including neutrophil defensin alpha 4, CXCR1, Rab3a, and S100-A7 were more abundant. The data suggest differences in important neutrophil proteins that might impact immunological processes. However, in vitro experiments revealed no apparent difference in the ability to control bacteria nor produce oxygen radicals. In subsets isolated from patients with septic shock, 24 proteins including cytochrome b-245 chaperone 1 had significantly higher abundance in Olfm4-H and 30 in Olfm4-L, including Fc receptor proteins. There was no correlation between Olfm4-H proportion and septic shock severity, but plasma Olfm4 concentration was elevated in septic shock. Thus, the Olfm4-H and Olfm4-L neutrophils have different proteomic profiles, but there was no evident functional significance of the differences in septic shock.

[The Clinical Value of Neutrophil CD64 Index in Hematological Malignancies with Pulmonary Infection]

OBJECTIVE

To investigate the clinical value of neutrophil CD64 index in hematological malignancies with pulmonary infection.

METHODS

The cohort study method was used to retrospectively analyze the clinical data of 125 patients with hematological malignancies and pulmonary infections who were treated in The Third Affiliated Hospital of Soochow University. All the patients were divided into four stages according to the diagnosis and treatment process: non-infected stage (T1), the symptoms of infection had appeared before using antibiotics (T2), one week after anti-infective treatment (T3), and after stopping antibiotics (T4). CD64 index, C-reactive protein (CRP), blood cell count, and immune cell level were compared before and after infection (T1 vs T2), the correlation between CD64 index and other indicators were explored, the change trends of the significantly different indicators in the course of the disease were observed, and the diagnostic efficacy of CD64 index and CRP were compared. The surviving patients were followed up for whether reinfection occurred within 30 days after discharge, and the re-examination results of indices before discharge (in stage of T4) between reinfected and non-reinfected patients were compared to find the risk factors of reinfection.

RESULTS

Before and after infection, the CD64 index, CRP, CD14⁺HLA-DR⁺, CD4⁺, and lymphocyte counts were significantly different (all P<0.05). There was a negative correlation of CD64 index with CD14⁺HLA-DR⁺ (r=-0.395, P<0.001), a negative correlation with CD3⁺ (r=-0.1.87, P=0.047), and a negative correlation with lymphocyte count (r=-0.230, P=0.006), while a positive correlation with CRP(r=0.313, P<0.001). The area under the curve of CD64 index, CRP, and CD64 index combined with CRP was 0.790 (95%CI: 0.711-0.868), 0.754(95%CI: 0.667-0.841), and 0.835(95%CI: 0.762-0.907), respectively; the sensitivity was 59.6%, 72.7%, and 74.7%, the specificity was 89.2%, 73.0%, and 78.4%, and the cut-off value was 0.488, 0.457, and 0.531, respectively. There were only two re-examination indexes showed significantly different before discharge between reinfected patients and non-reinfected patients: CD14⁺HLA-DR⁺ (F=8.524, P=0.004) and CD64 index (F=9.993, P=0.002). The increase of CD64 index was an independent risk factor for reinfection within 30 days after discharge from the hospital (HR=1.790, 95%CI: 1.343-2.386, P<0.001).

CONCLUSION

CD64 index has diagnostic value in patients with hematological malignancies and pulmonary infection, and its specificity is higher than that of CRP. The combination of the two indicators can improve the diagnostic sensitivity. CD64 index has a predictive value for reinfection within 30 days after infection treatment.

Procalcitonin concentration in the emergency department predicts 30-day mortality in COVID-19 better than the lymphocyte count, the neutrophil-tolymphocyte ratio, or the C-reactive protein level

OBJECTIVES

Although many demographic and clinical predictors of mortality have been studied in relation to COVID-19, little has been reported about the prognostic utility of inflammatory biomarkers.

MATERIAL AND METHODS

Retrospective cohort study. All patients with laboratory-confirmed COVID-19 treated in a hospital emergency department were included consecutively if baseline measurements of the following biomarkers were on record: lymphocyte counts, neutrophil-to-lymphocyte ratio NRL, and C-reactive protein (CRP) and procalcitonin (PCT) levels. We analyzed associations between the biomarkers and all-cause 30-day mortality using Cox regression models and dose-response curves.

RESULTS

We included 896 patients, 151 (17%) of whom died within 30 days. The median (interquartile range) age was 63 (51-78) years, and 494 (55%) were men. NLR, CRP and PCT levels at ED presentation were higher, while lymphocyte counts were lower, in patients who died compared to those who survived (P .001). The areas under the receiver operating characteristic curves revealed the PCT concentration (0.79; 95% CI, 0.75-0.83) to be a better predictor of 30-day mortality than the lymphocyte count (0.70; 95% CI, 0.65-0.74; P .001), the NLR (0.74; 95% CI, 0.69-0.78; P = .03), or the CRP level (0.72; 95% CI, 0.68-0.76; P .001). The proposed PCT concentration decision points for use in emergency department case management were 0.06 ng/L (negative) and 0.72 ng/L (positive). These cutoffs helped classify risk in 357 patients (40%). Multivariable analysis demonstrated that the PCT concentration had the strongest association with mortality.

CONCLUSION

PCT concentration in the emergency department predicts all-cause 30-day mortality in patients with COVID-19 better than other inflammatory biomarkers.

Association of maternal neutrophil count in early pregnancy with the development of gestational diabetes mellitus: a prospective cohort study in China

OBJECTIVE

We evaluated the potential role of maternal serum levels of neutrophils in the first trimester of pregnancy in the prediction of gestational diabetes mellitus (GDM).

METHODS

This prospective cohort study enrolled singleton pregnant women before gestational weeks 16 and evaluated them until delivery. Among the 1467 pregnant women who performed prenatal care before 14 weeks of gestation in the cohort, a total of 731 were eligible for the final analysis. The associations between neutrophil counts, white blood cell count, neutrophil to lymphocyte ratio, and GDM (assessed by a 75-g oral glucose tolerance test between 24 and 28 weeks) were evaluated by multivariate logistic regression.

RESULTS

Neutrophil count outperformed the neutrophil to lymphocyte ratio and white blood cell count in predicting GDM occurrence. We applied a smoothing function and found that neutrophil count was associated with both fasting blood glucose (FBG) (p=.0149) and 1-h postprandial blood glucose (PBG) (p=.0187) after adjustment pre-pregnancy body mass index, family history of diabetes, and age. Logistic regression analysis found that the highest neutrophil count level (6.28-14.73 × 10⁹/L) had a 1.85-fold (95% CI 1.10, 3.09) increased risk of GDM compared with that of the lowest tertile (1.47-4.82 × 10⁹/L).

CONCLUSIONS

The results indicated an association between higher neutrophil levels and GDM occurrence.

Comparative analysis of antibody- and lipid-based multiplexing methods for single-cell RNA-seq

BACKGROUND

Multiplexing of samples in single-cell RNA-seq studies allows a significant reduction of the experimental costs, straightforward identification of doublets, increased cell throughput, and reduction of sample-specific batch effects. Recently published multiplexing techniques using oligo-conjugated antibodies or -lipids allow barcoding sample-specific cells, a process called "hashing."

RESULTS

Here, we compare the hashing performance of TotalSeq-A and -C antibodies, custom synthesized lipids and MULTI-seq lipid hashes in four cell lines, both for single-cell RNA-seq and single-nucleus RNA-seq. We also compare TotalSeq-B antibodies with CellPlex reagents (10x Genomics) on human PBMCs and TotalSeq-B with different lipids on primary mouse tissues. Hashing efficiency was evaluated using the intrinsic genetic variation of the cell lines and mouse strains. Antibody hashing was further evaluated on clinical samples using PBMCs from healthy and SARS-CoV-2 infected patients, where we demonstrate a more affordable approach for large single-cell sequencing clinical studies, while simultaneously reducing batch effects.

CONCLUSIONS

Benchmarking of different hashing strategies and computational pipelines indicates that correct demultiplexing can be achieved with both lipid- and antibody-hashed human cells and nuclei, with MULTISeqDemux as the preferred demultiplexing function and antibody-based hashing as the most efficient protocol on cells. On nuclei datasets, lipid hashing delivers the best results. Lipid hashing also outperforms antibodies on cells isolated from mouse brain. However, antibodies demonstrate better results on tissues like spleen or lung.

Delta neutrophil index and C-reactive protein: a potential diagnostic marker of multisystem inflammatory syndrome in children (MIS-C) with COVID-19

Multisystem inflammatory syndrome in children (MIS-C) is a life-threatening hyperinflammation syndrome emerging after COVID-19. The serum delta neutrophil index (DNI) reflects the fraction of circulating immature granulocytes and is evaluated in infection and inflammation. The aim of this study is to evaluate the usefulness of DNI as a diagnostic marker in patients with MIS-C and to assess its role in determining the severity of MIS-C. This retrospective, observational study included 83 patients with MIS-C and 113 patients with COVID-19, and 102 healthy controls. C-reactive protein (CRP), the absolute neutrophil count (ANC), absolute lymphocyte count (ALC), DNI, and the platelet count were recorded. The DNI levels were 4.60 ± 5.70% in the MIS C group, 0.30 ± 0.99% in the COVID group, and 0.20 ± 0.56% in the control group (p < 0.001). According to the severity of MIS-C, the DNI level was found to be 1.22% in mild MIS-C, 4.3% in moderate MIS-C, and 5.7% in severe MIS-C. There was a statistically significant correlation between DNI levels and the severity of MIS-C. The cutoff value of DNI for predicting MIS-C was 0.45%. In the analysis of the diagnostic performance of DNI compared with CRP, ANC, ALC and platelet counts, sensitivity, specificity, positive predictive value, and negative predictive value were found to be 79.5%, 97.1%, 95.7%, and 85.3%, respectively.Conclusions: The delta neutrophil index was identified as a diagnostic marker for MIS-C such as ANC, ALC, platelet count, and CRP. DNI levels in hemogram analysis may guide clinicians in determining the diagnosis and severity of MIS-C. What is Known: • Although CRP, sedimentation, ALC, ANC, platelet count, sodium, and albumin are used as first step tests, there is no specific laboratory marker used in the diagnosis of MIS C. • The serum delta neutrophil index (DNI) reflects the fraction of circulating immature granulocytes and is elevated in infection and inflammation. What is New: • DNI is a promising and easily accessible marker that can be used with other markers in the diagnosis and determines the severity of MIS C. • DNI is an easily accessible, inexpensive, and dynamic marker and its levels in simple hemogram analysis will guide pediatricians in determining the diagnosis and severity in MIS C.

Tumor-Associated Neutrophil Extracellular Traps Regulating Nanocarrier-Enhanced Inhibition of Malignant Tumor Growth and Distant Metastasis

Tumor-associated neutrophil extracellular traps (NETs) play a critical role in promoting tumor growth and assisting tumor metastasis. Herein, a smart nanocarrier (designated as mP-NPs-DNase/PTX) based on regulating tumor-associated NETs has been developed, which consists of a paclitaxel (PTX) prodrug nanoparticle core and a poly-l-lysine (PLL) conjugated with the matrix metalloproteinase 9 (MMP-9)-cleavable Tat-peptide-coupled deoxyribonuclease I (DNase I) shell. After accumulating at the site of the tumor tissue, the nanocarrier can release DNase I in response to MMP-9 to degrade the structure of NETs. Then, the remaining moiety can uptake the tumor cells via the mediation of exposed cell penetrating peptide, and the PTX prodrug nanoparticles will lyse in response to the high intracellular concentration of reduced glutathione to release PTX to exert a cytotoxic effect of tumor cells. Through in vitro and in vivo evaluations, it has been proven that mP-NPs-DNase/PTX could serve as potential NET-regulated nanocarrier for enhanced inhibition of malignant tumor growth and distant metastasis.

Visualizing hypochlorous acid production by human neutrophils with fluorescent graphene quantum dots

In living organisms, redox reactions play a crucial role in the progression of disorders accompanied by the overproduction of reactive oxygen and reactive chlorine species, such as hydrogen peroxide and hypochlorous acid, respectively. We demonstrate that green fluorescence graphene quantum dots (GQDs) can be employed for revealing the presence of the hypochlorous acid in aqueous solutions and cellular systems. Hypochlorous acid modifies the oxygen-containing groups of the GQD, predominantly opens epoxide ring C-O-C, forms excessive C=O bonds and damages the carbonic core of GQDs. These changes, which depend on the concentration of the hypochlorous acid and exposure time, manifest themselves in the absorbance and fluorescence spectra of the GQD, and in the fluorescence lifetime. We also show that the GQD fluorescence is not affected by hydrogen peroxide. This finding makes GQDs a promising sensing agent for selective detecting reactive chlorine species produced by neutrophils. Neutrophils actively accumulate GQDs allowing to visualize cells and to examine the redox processes via GQDs fluorescence. At high concentrations GQDs induce neutrophil activation and myeloperoxidase release, leading to the disruption of GQD structure by the produced hypochlorous acid. This makes the GQDs a biodegradable material suitable for various biomedical applications.

Determination of tigecycline in human lung epithelial cells and polymorphonuclear neutrophils by liquid chromatography/tandem mass spectrometry and its application in a cellular pharmacokinetics study

RATIONALE

In order to characterize the intracellular pharmacokinetic properties of tigecycline, we developed and fully validated a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for quantification of tigecycline in human lung epithelial (BEAS-2B) cells and polymorphonuclear neutrophils (PMNs).

METHODS

Tetracycline was used as an internal standard and chromatographic separation was achieved on a C18 Hypersil Gold aQ column using two mobile phases, a solution of water (containing 0.1% formic acid) and acetonitrile. The flow rate was 0.4 mL/min for 5.0 min. Tigecycline drug uptake was evaluated by incubating the BEAS-2B cells and the PMNs for up to 3 h at tigecycline concentrations of 1 mg/L.

RESULTS

The assay was linear over the tested concentration range of 0.01-2 mg/L for tigecycline in BEAS-2B cells and PMNs (r²  >0.99). The inter- and inter-day precisions (RSD, %) were <10.02% and the accuracies (%) were within the range of 85-115%. The uptake study showed that after incubation with tigecycline (1 mg/L) for 3 h at 37°C, the intracellular peak concentration of BEAS-2B cells was 14.44 ± 7.12 mg/L at 1 h, and 41.43 ± 25.66 mg/L in PMNs at 20 min. The mean intracellular concentrations fluctuated in the range of 0.8-14.44 mg/L in BEAS-2B cells and 10.14-41.43 mg/L in PMNs for 1 mg/L tigecycline exposure.

CONCLUSIONS

Validated LC/MS/MS is a simple, rapid, and sensitive method for determining the intracellular concentration of tigecycline, and tigecycline has good penetrations both in human BEAS-2B cells and PMNs. The method can be efficiently used for future studies of the intracellular pharmacokinetics of tigecycline.

Serum C-reactive protein and neutrophil-to-lymphocyte ratio as predictors of survival in cirrhotic patients with systemic inflammatory response syndrome and bacterial infection

BACKGROUND

Cirrhotic patients are prone to infections due to underlying immune dysfunction in them. We aimed to study the role of inflammatory markers, serum C-reactive protein (CRP) and neutrophil-to-lymphocyte ratio (NLR), in predicting infection, blood culture positivity, and short-term (1 month) mortality in hospitalized cirrhotic patients.

METHODS

This prospective study was done over a period of 14 months (October 2017 to November 2018). Patient data included age, gender, etiology of cirrhosis, reason for admission, and comorbidity. Laboratory tests included blood chemistry and blood cell counts, and blood and urine culture. The specific tests included were CRP and NLR. Survival of patients in the following 1 month was noted. Area under receiver operating characteristic curve (AUROC), sensitivity, specificity, predictive values, diagnostic accuracy were calculated and logistic regression analysis performed. A p-value < 0.05 was considered significant.

RESULTS

Two hundred and eight patients formed the study cohort. The median age was 51.5 years and male predominance was noted. Alcohol-related liver disease (49%) was the commonest etiology. The infection rate was 62%, culture positivity was 58.5%, and mortality was 30.8%. NLR and CRP were significantly higher in those with documented infection (culture positive or negative) and among nonsurvivors. Optimal cutoffs for NLR and CRP to predict infection were 5.86 and 33.7, respectively. The risk of having an infection was 7.5 times and about 15 times if NLR and CRP were above the cutoffs. The risk of 1-month mortality was 2-3 times higher if patients had NLR and CRP above the cutoffs. The combination of NLR and CRP (≥ 5.86 and ≥ 33.7, respectively) increased specificity and diagnostic accuracy for infection.

CONCLUSION

NLR and CRP were independently good predictors of infection and 1-month survival among the patients with cirrhosis of liver included in this study.

Retrospective Study of Clinical Features of COVID-19 in Inpatients and Their Association with Disease Severity

BACKGROUND The aim of this study was to analyze the clinical features and laboratory indices of patients with coronavirus disease (COVID-19) and explore their association with the severity of the disease. MATERIAL AND METHODS A total of 61 patients with COVID-19 were divided into groups with common symptoms and with severe diseases, and clinical data were collected to analyze and compare the differences between them. RESULTS In patients with severe COVID-19, compared with the common group, lymphocyte count and albumin levels were lower, and aspartate aminotransferase (AST), blood urea, blood creatinine, lactate dehydrogenase (LDH), and C-reactive protein (CRP) levels, and prothrombin time (PT) were elevated (all P<0.05). The neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), mean platelet volume-to-lymphocyte ratio (MPVLR), and C-reactive protein-to-albumin ratio (CAR) were significantly elevated in the severe group compared with the group with common symptoms; however, the lymphocyte-to-monocyte ratio (LMR) was significantly reduced (P<0.05). Univariate logistic regression showed that lower lymphocyte count, prolonged PT, elevated CRP and LDH levels, and elevated NLR, PLR, MPVLR, and CAR were risk factors for COVID-19 severity (P<0.05). Multivariate logistic regression showed that elevated CRP levels (odds ratio [OR], 0.028; 95% confidence interval [CI]: 0.002-0.526; P=0.017), prolonged PT (OR, 0.014; 95% CI: 0.001-0.341; P=0.09), and an MPVLR >8.9 (OR, 0.026; 95% CI: 0.002-0.349; P=0.006) were independent risk factors for COVID-19 severity. CONCLUSIONS Elevated CRP and prolonged PT, and an MPVLR >8.9 were independent risk factors for COVID-19 severity.

Unified control of amoeboid pseudopod extension in multiple organisms by branched F-actin in the front and parallel F-actin/myosin in the cortex

The trajectory of moving eukaryotic cells depends on the kinetics and direction of extending pseudopods. The direction of pseudopods has been well studied to unravel mechanisms for chemotaxis, wound healing and inflammation. However, the kinetics of pseudopod extension-when and why do pseudopods start and stop- is equally important, but is largely unknown. Here the START and STOP of about 4000 pseudopods was determined in four different species, at four conditions and in nine mutants (fast amoeboids Dictyostelium and neutrophils, slow mesenchymal stem cells, and fungus B.d. chytrid with pseudopod and a flagellum). The START of a first pseudopod is a random event with a probability that is species-specific (23%/s for neutrophils). In all species and conditions, the START of a second pseudopod is strongly inhibited by the extending first pseudopod, which depends on parallel filamentous actin/myosin in the cell cortex. Pseudopods extend at a constant rate by polymerization of branched F-actin at the pseudopod tip, which requires the Scar complex. The STOP of pseudopod extension is induced by multiple inhibitory processes that evolve during pseudopod extension and mainly depend on the increasing size of the pseudopod. Surprisingly, no differences in pseudopod kinetics are detectable between polarized, unpolarized or chemotactic cells, and also not between different species except for small differences in numerical values. This suggests that the analysis has uncovered the fundament of cell movement with distinct roles for stimulatory branched F-actin in the protrusion and inhibitory parallel F-actin in the contractile cortex.

Site-Specific Glycosylation Mapping of Fc Gamma Receptor IIIb from Neutrophils of Individual Healthy Donors

Fc gamma receptors (FcγRs) translate antigen recognition by immunoglobulin G (IgG) into various immune responses. A better understanding of this key element of immunity promises novel insights into mechanisms of (auto-/allo-)immune diseases and more rationally designed antibody-based drugs. Glycosylation on both IgG and FcγR impacts their interaction dramatically. Regarding FcγR glycosylation profiling, major analytical challenges are associated with the presence of multiple glycosylation sites in close proximity and large structural heterogeneity. To address these challenges, we developed a straightforward and comprehensive analytical methodology to map FcγRIIIb glycosylation in primary human cells. After neutrophil isolation and immunoprecipitation, glycopeptides containing a single site each were generated by a dual-protease in-gel digestion. The complex mixture was resolved by liquid chromatography-tandem mass spectrometry (LC-MS/MS) providing information on the level of individual donors. In contrast to recently published alternatives for FcγRIIIb, we assessed its site-specific glycosylation in a single LC-MS/MS run and simultaneously determined the donor allotype. Studying FcγRIIIb derived from healthy donor neutrophils, we observed profound differences as compared to the soluble variant and the homologous FcγRIIIa on natural killer cells. This method will allow assessment of differences in FcγRIII glycosylation between individuals, cell types, subcellular locations, and pathophysiological conditions.

Phenotypical and functional abnormalities of circulating neutrophils in patients with β-thalassemia

β-Thalassemia is an inherited single gene disorder related to reduced synthesis of the β-globin chain of hemoglobin. Patients with β-thalassemia present variable clinical severity ranging from asymptomatic trait to severe transfusion-dependent anemia and multiple organs complications. Moreover, multiple immune abnormalities are a major concern in β-thalassemia patients. Aberrant neutrophil effector function plays a pivotal role in infection susceptibility in these patients. In severe and persistent inflammation, immature neutrophils are released from the bone marrow and are functionally different compared with mature ones. Despite some abnormalities reported for thalassemia patient's immune system, few data exist on the characterization of human neutrophils in β-thalassemia. The aim of this study was to investigate the phenotype and function of circulating neutrophil subsets in patients with β-thalassemia major and with β-thalassemia intermedia divided in transfusion-dependent and non-transfusion-dependent. By the use of immunochemical and cytofluorimetric analyses, we observed that patients' CD16+ neutrophils exhibit abnormalities in their phenotype and functions and the abnormalities vary according to the clinical form of the disease and to the neutrophil subset (CD16^bright and CD16^dim). Abnormalities include altered surface expression of the innate immune receptor CD45, Toll-like receptor 4, and CD32, reduced ability to produce an oxidative burst, and elevated levels of membrane lipid peroxidation, especially in patients with a more severe form of the disease. Overall, our results indicating the occurrence of an immuno-senescent phenotype on circulating neutrophils from thalassemia patients suggest the usefulness of neutrophil feature assessment as a tool for better clinical management of β-thalassemia.

Induction of neutrophil extracellular traps by Campylobacter jejuni

Campylobacter jejuni is the leading cause of bacterial-derived gastroenteritis worldwide and can lead to several post-infectious inflammatory disorders. Despite the prevalence and health impacts of the bacterium, interactions between the host innate immune system and C. jejuni remain poorly understood. To expand on earlier work demonstrating that neutrophils traffic to the site of infection in an animal model of campylobacteriosis, we identified significant increases in several predominantly neutrophil-derived proteins in the faeces of C. jejuni-infected patients, including lipocalin-2, myeloperoxidase and neutrophil elastase. In addition to demonstrating that these proteins significantly inhibited C. jejuni growth, we determined they are released during formation of C. jejuni-induced neutrophil extracellular traps (NETs). Using quantitative and qualitative methods, we found that purified human neutrophils are activated by C. jejuni and exhibit signatures of NET generation, including presence of protein arginine deiminase-4, histone citrullination, myeloperoxidase, neutrophil elastase release and DNA extrusion. Production of NETs correlated with C. jejuni phagocytosis/endocytosis and invasion of neutrophils suggesting that host- and bacterial-mediated activities are responsible for NET induction. Further, NET-like structures were observed within intestinal tissue of C. jejuni-infected ferrets. Finally, induction of NETs significantly increased human colonocyte cytotoxicity, indicating that NET formation during C. jejuni infection may contribute to observed tissue pathology. These findings provide further understanding of C. jejuni-neutrophil interactions and inflammatory responses during campylobacteriosis.

Sensitive and rapid lateral-flow assay for early detection of subclinical mammary infection in dairy cows

Detection of subclinical mastitis (SCM) in its initial stage can save great economic losses, improve milk quality and animal welfare. We have developed a semiquantitative lateral flow assay for the detection of SCM in dairy cows targeting myeloperoxidase (MPO) enzyme of milk neutrophils. A competitive immunoassay format was used, and colloidal gold nanoparticles (GNP) were prepared and used as a labelling agent. Monoclonal anti-MPO antibodies were used and assessed for its quality by enzyme-linked immunosorbent assay and dot blot. Conjugation method for GNP and anti-MPO antibodies was standardised, and the conjugate was placed over the conjugate pad. MPO coupled with a carrier protein (OVA) and the species-specific secondary antibodies were placed on test and control lines, respectively. The developed assay was verified with 75 milk samples collected from healthy, SCM and clinical mastitis cows. It displayed a high sensitivity as it could detect MPO as low as 1.5 ng/ml, an accuracy greater than 97% and showed no crossreactivity when crosschecked with other milk proteins. The developed assay can be used as an alternative for SCM diagnostic tests where lab structure are available for obtaining the lysate of milk SCC.

A Neutrophil-Inspired Supramolecular Nanogel for Magnetocaloric-Enzymatic Tandem Therapy

Neutrophils can responsively release reactive oxygen species (ROS) to actively combat infections by exogenous stimulus and cascade enzyme catalyzed bio-oxidation. A supramolecular nanogel is now used as an artificial neutrophil by enzymatic interfacial self-assembly of peptides (Fmoc-Tyr(H₂ PO₃ )-OH) with magnetic nanoparticles (MNPs) and electrostatic loading of chloroperoxidase (CPO). The MNPs within the nanogel can elevate H₂ O₂ levels in cancer cells under programmed alternating magnetic field (AMF) similar to the neutrophil activator, and the loaded CPO within protective peptides nanolayer converts the H₂ O₂ into singlet oxygen (¹ O₂ ) in a sustained manner for neutrophil-inspired tumor therapy. As a proof of concept study, both the H₂ O₂ and ¹ O₂ in cancer cells increase stepwise under a programmed alternating magnetic field. An active enzyme dynamic therapy by magnetically stimulated oxygen stress and sustained enzyme bio-oxidation is thus shown with studies on both cells and animals.

Phenolic acid phenethylesters and their corresponding ketones: Inhibition of 5-lipoxygenase and stability in human blood and HepaRG cells

5-lipoxygenase (5-LO) catalyzes the biosynthesis of leukotrienes, potent lipid mediators involved in inflammatory diseases, and both 5-LO and the leukotrienes are validated therapeutic targets. Caffeic acid phenethyl ester (CAPE) is an effective inhibitor of 5-LO and leukotriene biosynthesis but is susceptible to hydrolysis by esterases. In this study a number of CAPE analogues were synthesized with modifications to the caffeoyl moiety and the replacement of the ester linkage with a ketone. Several new molecules showed better inhibition of leukotriene biosynthesis than CAPE in isolated human neutrophils and in whole blood with IC50 values in the nanomolar (290-520 nmol/L) and low micromolar (1.0-2.3 µmol/L) ranges, respectively. Sinapic acid and 2,5-dihydroxy derivatives were more stable than CAPE in whole blood, and ketone analogues were degraded more slowly in HepaRG hepatocyte cultures than esters. All compounds underwent modification consistent with glucuronidation in HepaRG cultures as determined using LC-MS/MS analysis, though the modified sinapoyl ketone (10) retained 50% of its inhibitory activity after up to one hour of incubation. This study has identified at least one CAPE analogue, compound 10, that shows favorable properties that warrant further in vivo investigation as an antiinflammatory compound.

Extracellular vesicles as mediators of in vitro neutrophil swarming on a large-scale microparticle array

Neutrophils combat infections and promote healing of damaged tissues while protecting the surrounding healthy tissue through a process called swarming. Swarming neutrophils release soluble factors that recruit additional neutrophils and shape the inflammation response. Additionally, neutrophils release extracellular vesicles (EVs), which are gaining attention as important intercellular mediators. We developed a large-scale array of bioparticles on a glass substrate that triggers neutrophil swarming in vitro in a spatially and temporally controlled manner that facilitates the analysis of neutrophil migration. Our platform can generate 30 000 neutrophil swarms on a glass slide in a highly reproducible manner (98% patterning efficiency), which produces an EV-rich supernatant that enables quantitative characterization of inflammation-specific EVs. Healthy neutrophils were able to form uniform swarms across the bioparticle array, which demonstrates a high degree of intercellular coordination. However, neutrophils swarming on the bioparticle array tended to have a lower radial velocity than neutrophils swarming toward a single target. After collecting and isolating EVs released by swarming and non-swarming neutrophils, we found that neutrophils constitutively release exosomes and microvesicles. Furthermore, EVs released by swarming neutrophils cause neutrophil activation and contain the proinflammatory mediator galectin-3, suggesting that EVs have an active role during neutrophil swarming. Ultimately, understanding EVs' role in intercellular communication during swarming will improve understanding of the complex signaling pathways involved in the regulation of inflammation.

Artificial Super Neutrophils for Inflammation Targeting and HClO Generation against Tumors and Infections

Neutrophils are powerful effector leukocytes that play an important role in innate immune systems for opposing tumor progression and ameliorating pathogen infections. Inspired by their distinct functions against tumors and infections, the artificial "super neutrophils" are proposed with excellent inflammation targeting and hypochlorous acid (HClO) generation characteristics for targeting and eliminating malignant tumor cells and pathogens. The "super neutrophils" are fabricated by embedding glucose oxidase (GOx) and chloroperoxidase (CPO) into zeolitic imidazolate framework-8 (ZIF-8) for HClO generation via enzymatic cascades, and then encapsulating them with the neutrophil membrane (NM) for inflammation targeting. In vitro and in vivo results indicate that these artificial "super neutrophils" can generate seven times higher reactive HClO than the natural neutrophils for eradicating tumors and infections. The "super neutrophils" demonstrated here with easy fabrication and good neutrophil-mimicking property exhibit great potential for biomedical applications.

Neutrophil Membrane-Derived Nanovesicles Alleviate Inflammation To Protect Mouse Brain Injury from Ischemic Stroke

Ischemic stroke is an acute and severe neurological disease, resulting in disability and death. Reperfusion to an ischemic brain is a means to reverse brain damage after stroke; however, this causes secondary tissue damage induced by inflammation responses, called ischemia/reperfusion (I/R) injury. Adhesion of neutrophils to endothelial cells underlies the initiation of inflammation in I/R. Inspired by this interaction, we report a drug delivery system comprised of neutrophil membrane-derived nanovesicles loaded with Resolvin D2 (RvD2) that can enhance resolution of inflammation, thus protecting brain damage during ischemic stroke. In the study, the middle cerebral artery occlusion (MCAO) mouse model was developed to mimic ischemic stroke. Using intravital microscopy of a live mouse brain, we visualized the binding of nanovesicles to inflamed brain vasculature for delivery of therapeutics to ischemic stroke lesions in real-time. We also observed that RvD2-loaded nanovesicles dramatically decreased inflammation in ischemic stroke and improved mouse neurological functions. Our study provides a strategy to inhibit neuroinflammation using neutrophil-derived nanovesicles for ischemic stroke therapy.

Hydroxyethyl Starch 130/0.4 Binds to Neutrophils Impairing Their Chemotaxis through a Mac-1 Dependent Interaction

Several studies showed that hydroxyethyl starch (HES), a synthetic colloid used in volume replacement therapies, interferes with leukocyte-endothelium interactions. Although still unclear, the mechanism seems to involve the inhibition of neutrophils' integrin. With the aim to provide direct evidence of the binding of HES to neutrophils and to investigate the influence of HES on neutrophil chemotaxis, we isolated and treated the cells with different concentrations of fluorescein-conjugated HES (HES-FITC), with or without different stimuli (N-Formylmethionine-leucyl-phenylalanine, fMLP, or IL-8). HES internalization was evaluated by trypan blue quenching and ammonium chloride treatment. Chemotaxis was evaluated by under-agarose assay after pretreatment of the cells with HES or a balanced saline solution. The integrin interacting with HES was identified by using specific blocking antibodies. Our results showed that HES-FITC binds to the plasma membrane of neutrophils without being internalized. Additionally, the cell-associated fluorescence increased after stimulation of neutrophils with fMLP (p < 0.01) but not IL-8. HES treatment impaired the chemotaxis only towards fMLP, event mainly ascribed to the inhibition of CD-11b (Mac-1 integrin) activity. Therefore, the observed effect mediated by HES should be taken into account during volume replacement therapies. Thus, HES treatment could be advantageous in clinical conditions where a low activation/recruitment of neutrophils may be beneficial, but may be harmful when unimpaired immune functions are mandatory.

Sulphamethazine derivatives as immunomodulating agents: New therapeutic strategies for inflammatory diseases

Sulfamethazine (SMZ) (1) is an antibacterial sulfa drug which suppresses the synthesis of dihydrofolic acid. It is used for the treatment of infections in livestock; such as gastrointestinal, and respiratory tract infections. During the current study, synthesis, characterization, and evaluation of immunomodulatory activities of derivatives of sulfamethazine (SMZ) (3-39) was carried out. These derivatives were synthesized by the reaction of sulfamethazine with a range of acid chlorides. All the compounds were characterized by using modern spectroscopic techniques, such as 1H-, and 13C-NMR, EI-MS, and HRFAB-MS. Compounds 3-10, 14, and 15 were identified as new compounds. Immunomodulatory effect of compounds 3-39 on different parameters of innate immune response was evaluated, including the production of Reactive Oxygen Species (ROS) from human whole blood and isolated polymorphonuclear neutrophils (PMNs), nitric oxide (NO), and pro-inflammatory cytokine TNF-α. All the new compounds, except 14 and 15, showed a significant anti-inflammatory activity. Compounds 3-39 were also evaluated for their anti-bacterial activity and cytotoxicity (3T3 mouse fibroblast cell lines). All the compounds were found to be non-cytotoxic against normal cell lines.

Neutrophil membrane-coated nanoparticles inhibit synovial inflammation and alleviate joint damage in inflammatory arthritis

Rheumatoid arthritis is a common chronic inflammatory disorder and a major cause of disability. Despite the progress made with recent clinical use of anti-cytokine biologics, the response rate of rheumatoid arthritis treatment remains unsatisfactory, owing largely to the complexity of cytokine interactions and the multiplicity of cytokine targets. Here, we show a nanoparticle-based broad-spectrum anti-inflammatory strategy for rheumatoid arthritis management. By fusing neutrophil membrane onto polymeric cores, we prepare neutrophil membrane-coated nanoparticles that inherit the antigenic exterior and associated membrane functions of the source cells, which makes them ideal decoys of neutrophil-targeted biological molecules. It is shown that these nanoparticles can neutralize proinflammatory cytokines, suppress synovial inflammation, target deep into the cartilage matrix, and provide strong chondroprotection against joint damage. In a mouse model of collagen-induced arthritis and a human transgenic mouse model of arthritis, the neutrophil membrane-coated nanoparticles show significant therapeutic efficacy by ameliorating joint damage and suppressing overall arthritis severity.

Migration through a small pore disrupts inactive chromatin organization in neutrophil-like cells

BACKGROUND

Mammalian cells are flexible and can rapidly change shape when they contract, adhere, or migrate. The nucleus must be stiff enough to withstand cytoskeletal forces, but flexible enough to remodel as the cell changes shape. This is particularly important for cells migrating through confined spaces, where the nuclear shape must change in order to fit through a constriction. This occurs many times in the life cycle of a neutrophil, which must protect its chromatin from damage and disruption associated with migration. Here we characterized the effects of constricted migration in neutrophil-like cells.

RESULTS

Total RNA sequencing identified that migration of neutrophil-like cells through 5- or 14-μm pores was associated with changes in the transcript levels of inflammation and chemotaxis-related genes when compared to unmigrated cells. Differentially expressed transcripts specific to migration with constriction were enriched for groups of genes associated with cytoskeletal remodeling. Hi-C was used to capture the genome organization in control and migrated cells. Limited switching was observed between the active (A) and inactive (B) compartments after migration. However, global depletion of short-range contacts was observed following migration with constriction compared to migration without constriction. Regions with disrupted contacts, TADs, and compartments were enriched for inactive chromatin.

CONCLUSION

Short-range genome organization is preferentially altered in inactive chromatin, possibly protecting transcriptionally active contacts from the disruptive effects of migration with constriction. This is consistent with current hypotheses implicating heterochromatin as the mechanoresponsive form of chromatin. Further investigation concerning the contribution of heterochromatin to stiffness, flexibility, and protection of nuclear function will be important for understanding cell migration in relation to human health and disease.

Identification of urate hydroperoxide in neutrophils: A novel pro-oxidant generated in inflammatory conditions

Uric acid is the final product of purine metabolism in humans and is considered to be quantitatively the main antioxidant in plasma. In vitro studies showed that the oxidation of uric acid by peroxidases, in presence of superoxide, generates urate free radical and urate hydroperoxide. Urate hydroperoxide is a strong oxidant and might be a relevant intermediate in inflammatory conditions. However, the identification of urate hydroperoxide in cells and biological samples has been a challenge due to its high reactivity. By using mass spectrometry, we undoubtedly demonstrated the formation of urate hydroperoxide and its corresponding alcohol, hydroxyisourate during the respiratory burst in peripheral blood neutrophils and in human leukemic cells differentiated in neutrophils (dHL-60). The respiratory burst was induced by phorbol myristate acetate (PMA) and greatly increased oxygen consumption and superoxide production. Both oxygen consumption and superoxide production were further augmented by incubation with uric acid. Conversely, uric acid significantly decreased the levels of HOCl, probably because of the competition with chloride by the catalysis of myeloperoxidase. In spite of the decrease in HOCl, the overall oxidative status, measured by GSH/GSSG ratio, was augmented in the presence of uric acid. In summary, the present results support the formation of urate hydroperoxide, a novel oxidant in neutrophils oxidative burst. Urate hydroperoxide is a strong oxidant and alters the redox balance toward a pro-oxidative environment. The production of urate hydroperoxide in inflammatory conditions could explain, at least in part, the harmful effect associated to uric acid.

Leukocytes as a reservoir of circulating oncogenic DNA and regulatory targets of tumor-derived extracellular vesicles

Essentials Tumor-bearing mice were employed to follow oncogenic HRAS sequences in plasma, and blood cells. Cancer DNA accumulated in leukocytes above levels detected in exosomes, platelets and plasma. Extracellular vesicles and nucleosomes are required for uptake of tumor DNA by leukocytes. Uptake of tumor-derived extracellular vesicles by leukocytes triggers coagulant phenotype.

SUMMARY

Background Tumor-derived extracellular vesicles (EVs) and free nucleosomes (NSs) carry into the circulation a wealth of cancer-specific, bioactive and poorly understood molecular cargoes, including genomic DNA (gDNA). Objective Here we investigated the distribution of extracellular oncogenic gDNA sequences (HRAS and HER2) in the circulation of tumor-bearing mice. Methods and Results Surprisingly, circulating leukocytes (WBCs), especially neutrophils, contained the highest levels of mutant gDNA, which exceeded the amount of this material recovered from soluble fractions of plasma, circulating EVs, platelets, red blood cells (RBCs) and peripheral organs, as quantified by digital droplet PCR (ddPCR). Tumor excision resulted in disappearance of the WBC-associated gDNA signal within 2-9 days, which is in line with the expected half-life of these cells. EVs and nucleosomes were essential for the uptake of tumor-derived extracellular DNA by neutrophil-like cells and impacted their phenotype. Indeed, the exposure of granulocytic HL-60 cells to EVs from HRAS-driven cancer cells resulted in a selective increase in tissue factor (TF) procoagulant activity and interleukin 8 (IL-8) production. The levels of circulating thrombin-antithrombin complexes (TAT) were markedly elevated in mice harboring HRAS-driven xenografts. Conclusions Myeloid cells may represent a hitherto unrecognized reservoir of cancer-derived, EV/NS-associated oncogenic gDNA in the circulation, and a possible novel platform for liquid biopsy in cancer. In addition, uptake of this material alters the phenotype of myeloid cells, induces procoagulant and proinflammatory activity and may contribute to systemic effects associated with cancer.

A map of gene expression in neutrophil-like cell lines

BACKGROUND

Human neutrophils are central players in innate immunity, a major component of inflammatory responses, and a leading model for cell motility and chemotaxis. However, primary neutrophils are short-lived, limiting their experimental usefulness in the laboratory. Thus, human myeloid cell lines have been characterized for their ability to undergo neutrophil-like differentiation in vitro. The HL-60 cell line and its PLB-985 sub-line are commonly used to model human neutrophil behavior, but how closely gene expression in differentiated cells resembles that of primary neutrophils has remained unclear.

RESULTS

In this study, we compared the effectiveness of differentiation protocols and used RNA sequencing (RNA-seq) to compare the transcriptomes of HL-60 and PLB-985 cells with published data for human and mouse primary neutrophils. Among commonly used differentiation protocols for neutrophil-like cell lines, addition of dimethyl sulfoxide (DMSO) gave the best combination of cell viability and expression of markers for differentiation. However, combining DMSO with the serum-free-supplement Nutridoma resulted in increased chemotactic response, phagocytic activity, oxidative burst and cell surface expression of the neutrophil markers FPR1 and CD11b without a cost in viability. RNA-seq analysis of HL-60 and PLB-985 cells before and after differentiation showed that differentiation broadly increases the similarity in gene expression between the cell lines and primary neutrophils. Furthermore, the gene expression pattern of the differentiated cell lines correlated slightly better with that of human neutrophils than the mouse neutrophil pattern did. Finally, we created a publicly available gene expression database that is searchable by gene name and protein domain content, where users can compare gene expression in HL-60, PLB-985 and primary human and mouse neutrophils.

CONCLUSIONS

Our study verifies that a DMSO-based differentiation protocol for HL-60 and PLB-985 cell lines gives superior differentiation and cell viability relative to other common protocols, and indicates that addition of Nutridoma may be preferable for studies of chemotaxis, phagocytosis, or oxidative burst. Our neutrophil gene expression database will be a valuable tool to identify similarities and differences in gene expression between the cell lines and primary neutrophils, to compare expression levels for genes of interest, and to improve the design of tools for genetic perturbations.

Selectins and chemokines use shared and distinct signals to activate β2 integrins in neutrophils

Rolling neutrophils receive signals while engaging P- and E-selectin and chemokines on inflamed endothelium. Selectin signaling activates β2 integrins to slow rolling velocities. Chemokine signaling activates β2 integrins to cause arrest. Despite extensive study, key aspects of these signaling cascades remain unresolved. Using complementary in vitro and in vivo assays, we found that selectin and chemokine signals in neutrophils triggered Rap1a-dependent and phosphatidylinositol-4-phosphate 5-kinase γ (PIP5Kγ90)-dependent pathways that induce integrin-dependent slow rolling and arrest. Interruption of both pathways, but not either pathway alone, blocked talin-1 recruitment to and activation of integrins. An isoform of PIP5Kγ90 lacking the talin-binding domain (PIP5Kγ87) could not activate integrins. Chemokines, but not selectins, used phosphatidylinositol-4,5-bisphosphate 3-kinase γ (PI3Kγ) in cooperation with Rap1a to mediate integrin-dependent slow rolling (at low chemokine concentrations), as well as arrest (at high chemokine concentrations). High levels of chemokines activated β2 integrins without selectin signals. When chemokines were limiting, they synergized with selectins to activate β2 integrins.

Predictive value of the preoperative neutrophil-to-lymphocyte ratio for the development of hepatocellular carcinoma in HBV-associated cirrhotic patients after splenectomy

The neutrophil to lymphocyte ratio (NLR), a simple marker of inflammation, has recently been showed to predict tumor recurrence in hepatocellular carcinoma (HCC) patients after hepatic resection or liver transplantation. However, whether it can be used to predict HCC development in cirrhotic patients remained unknown. The aim of this study was to evaluate the predictive value of the preoperative NLR for the development of HCC in cirrhotic patients who underwent splenectomy. A total of 230 HBV-associated cirrhotic patients who underwent splenectomy in our hospital from January 2000 to December 2012 were included in this study. Detailed clinical data included patients’ general characteristics, laboratory tests and imaging studies, surgical procedures and complications. Information on patients’ follow-up data was also obtained. We found that 38 (16.52%) patients developed HCC after splenectomy during the follow-up period. An elevated preoperative NLR was associated with increased risk of developing HCC in cirrhotic patients after splenectomy. The optimal cutoff value of NLR for HCC development was 2.27. In patients who developed HCC during the follow-up period, NLR scores showed no predictive value in overall survival after splenectomy. However, NLR scores appeared to have a much better predictive value in overall survival in patients who did not develop HCC. In conclusion, cirrhotic patients who underwent splenectomy remain at a relatively high risk of developing HCC, and an elevated preoperative NLR is associated with HCC development in cirrhotic patients who underwent splenectomy for hypersplenism.

Neutrophil granule proteins generate bactericidal ammonia chloramine on reaction with hydrogen peroxide

The neutrophil enzyme, myeloperoxidase, by converting hydrogen peroxide (H₂O₂) and chloride to hypochlorous acid (HOCl), provides important defense against ingested micro-organisms. However, there is debate about how efficiently HOCl is produced within the phagosome and whether its reactions with phagosomal constituents influence the killing mechanism. The phagosome is a small space surrounding the ingested organism, into which superoxide, H₂O₂ and high concentrations of proteins from cytoplasmic granules are released. Previous studies imply that HOCl is produced in the phagosome, but a large proportion should react with proteins before reaching the microbe. To mimic these conditions, we subjected neutrophil granule extract to sequential doses of H₂O₂. Myeloperoxidase in the extract converted all the H₂O₂ to HOCl, which reacted with the granule proteins. 3-Chlorotyrosine, protein carbonyls and large amounts of chloramines were produced. At higher doses of H₂O₂, the extract developed potent bactericidal activity against Staphylococcus aureus. This activity was due to ammonia monochloramine, formed as a secondary product from protein chloramines and dichloramines. Isolated myeloperoxidase and elastase also became bactericidal when modified with HOCl and antibacterial activity was seen with a range of species. Comparison of levels of protein modification in the extract and in phagosomes implies that a relatively low proportion of phagosomal H₂O₂ would be converted to HOCl, but there should be sufficient for substantial protein chloramine formation and some breakdown to ammonia monochloramine. It is possible that HOCl could kill ingested bacteria by an indirect mechanism involving protein oxidation and monochloramine formation.

Neutrophil-Particle Interactions in Blood Circulation Drive Particle Clearance and Alter Neutrophil Responses in Acute Inflammation

Although nano- and microparticle therapeutics have been studied for a range of drug delivery applications, the presence of these particles in blood flow may have considerable and understudied consequences to circulating leukocytes, especially neutrophils, which are the largest human leukocyte population. The objective of this work was to establish if particulate drug carriers in circulation interfere with normal neutrophil adhesion and migration. Circulating blood neutrophils in vivo were found to be capable of rapidly binding and sequestering injected carboxylate-modified particles of both 2 and 0.5 μm diameter within the bloodstream. These neutrophil-particle associations within the vasculature were found to suppress neutrophil interactions with an inflamed mesentery vascular wall and hindered neutrophil adhesion. Furthermore, in a model of acute lung injury, intravenously administered drug-free particles reduced normal neutrophil accumulation in the airways of C57BL/6 mice between 52% and 60% versus particle-free mice and between 93% and 98% in BALB/c mice. This suppressed neutrophil migration resulted from particle-induced neutrophil diversion to the liver. These data indicate a considerable acute interaction between injected particles and circulating neutrophils that can drive variations in neutrophil function during inflammation and implicate neutrophil involvement in the clearance process of intravenously injected particle therapeutics. Such an understanding will be critical toward both enhancing designs of drug delivery carriers and developing effective therapeutic interventions in diseases where neutrophils have been implicated.

Isolation and functional analysis of syndecans

Syndecans comprise a major family of cell surface heparan sulfate proteoglycans (HSPGs). Syndecans are composed of sulfated glycosaminoglycans (GAGs), heparan sulfate (HS) or both HS and chondroitin sulfate (CS), attached covalently to core proteins. Syndecans regulate many cellular processes, such as adhesion, proliferation, and migration. Syndecans bind and regulate molecules primarily through their HS chains, but do not bind to all HS/heparin-binding molecules. Furthermore, mice ablated for the syndecan-1 or -4 gene do not show major developmental abnormalities, but they do show striking pathological phenotypes when challenged with infectious or inflammatory stimuli and conditions, suggesting that certain functions of syndecans are specific and cannot be compensated for by other syndecans or other HSPGs. These observations underscore the physiological importance of syndecans and indicate a need to study the activities of isolated native syndecans to define their molecular and cellular functions, and to establish their biological significance. Here we describe methods to isolate syndecans and several assays to analyze their functions.

A monoclonal antibody for detection of intracellular and secreted interleukin-2 in horses

Interleukin-2 (IL-2) is a T cell growth factor and major modulator of T helper (Th) cell differentiation. Here, we have developed and characterized a monoclonal antibody to equine IL-2 (anti-IL-2 mAb, clone 158-1). The IL-2 mAb detected rIL-2 by ELISA, intracellular staining and flow cytometry analysis and Western blotting. The IL-2 mAb was also paired with a polyclonal IL-2 detection antibody in both ELISA and a fluorescent bead-based assay. When these two assays were compared using identical reagents there was an improved analytical sensitivity (46pg/ml) and wider linear quantification range (46-100,000pg/ml) of IL-2 quantification using the fluorescent bead assay. Equine rIL-2 standards were expressed in both yeast and mammalian cells but the mammalian cell-expressed rIL-2 standard was found to be most accurate for native IL-2 quantification. Using this system we found that stimulation of equine peripheral blood mononuclear cells (PBMC) with phorbol 12-myristate 13-acetate (PMA) and ionomycin induced IL-2 secretion most potently. Pokeweed mitogen (PWM) consistently resulted in low amounts of IL-2 from PBMC, while concanavalin A (ConA), phytohemagglutinin-L (PHA-L) and lipopolysaccharide (LPS) either marginally stimulated or failed to stimulate IL-2 secretion from equine PBMC. After stimulation of equine PBMC with PMA and ionomycin, IL-2 production was detected in 13.0% (range 7.5-16.8%) of the lymphocytes by flow cytometric analysis. IL-2 expression was mainly stimulated in CD4⁺ cells, in a sub-population of CD8⁺ cells, and also in CD4-/CD8- cell population. In addition, both IFN-γ⁺/IL-2⁺ and IL-4⁺/IL-2⁺ producing cells were observed. Testing of serum and colostrum samples from 15 healthy horses showed that IL-2 was not detectable in these samples (<46pg/ml). In summary, the equine IL-2 mAb provides a new tool for the characterization of IL-2 producing equine cells and the quantification of secreted equine IL-2 in sensitive assays.

[Value of combined determination of neutrophil CD64 and procalcitonin in early diagnosis of neonatal bacterial infection]

OBJECTIVE

To investigate the value of combined determination of neutrophil CD64 and procalcitonin (PCT) in the early diagnosis of neonatal bacterial infection.

METHODS

According to discharge diagnosis, 37 neonates with bacterial infection were divided into sepsis (n=15) and ordinary infection (non-sepsis) groups (n=22). Twenty-one neonates without infection who were hospitalized during the same period of time were enrolled as the control group. Venous blood samples were collected immediately after admission. Flow cytometry was used to measure the serum level of neutrophil CD64. Chemiluminescence and immune transmission turbidimetry were used to measure the serum levels of PCT and CRP respectively.

RESULTS

The sepsis group had higher serum levels of neutrophil CD64, PCT, and CRP than the control group (P<0.01), the ordinary infection group had a higher serum level of neutrophil CD64 than the control group (P<0.01), and the sepsis group had higher serum levels of PCT and CRP than the ordinary infection group (P<0.01). The areas under the ROC curve (AUC) of neutrophil CD64, PCT, and CRP in diagnosing bacterial infection were 0.818, 0.818, and 0.704 respectively, and the AUC of combined neutrophil CD64 and PCT was 0.926. A combination of neutrophil CD64 and PCT had a sensitivity of 97.29% and an accuracy of 89.65% in the early diagnosis of neonatal bacterial infection.The sensitivity and accuracy were higher than those of a combination of CRP and neutrophil CD64 or PCT as well as neutrophil CD64, PCT, or CRP alone for the early diagnosis of neonatal bacterial infection.

CONCLUSIONS

The combined determination of neutrophil CD64 and PCT can improve the sensitivity and accuracy in the diagnosis of neonatal bacterial infection, which helps with early identification of bacterial infection.

Inflammation Modulatory Phorbol Esters from the Seeds of Aquilaria malaccensis

The tree Aquilaria malaccensis is a valuable source of agarwood, which is used in herbal medicinal preparations. Phytochemical research on A. malaccensis seeds has led to the isolation of four new phorbol esters (1-4), two known phorbol esters (5, isolated from Nature for the first time, and 6), and two known glycerides (7 and 8). The structures of these isolates were elucidated by means of spectroscopic data interpretation. The inflammation-modulatory activities of the isolates on elastase release and superoxide anion generation in human neutrophils were evaluated. Interestingly, phorbol esters 1, 5, and 6 showed potent inhibitory activity on elastase release in human neutrophils, with IC₅₀ values of 2.7, 0.8, and 2.1 μM, respectively. All isolated phorbol esters exerted enhancing activity on superoxide anion generation. The results indicated that phorbol esters may play a bilateral modulatory role in the processes of inflammation. In addition, the compounds were evaluated for their cytotoxic properties against HepG2 (hepatoma), MDA-MB-231 (breast), and A549 (lung) cancer cells, but all compounds were inactive for all cell lines used (IC₅₀ > 10 μM).

Inhibition of Myeloperoxidase- and Neutrophil-Mediated Hypochlorous Acid Formation in Vitro and Endothelial Cell Injury by (-)-Epigallocatechin Gallate

Myeloperoxidase (MPO) plays important roles in various diseases through its unique chlorinating activity to catalyze excess hypochlorous acid (HOCl) formation. Epidemiological studies indicate an inverse correlation between plant polyphenol consumption and the incidence of cardiovascular diseases. Here we showed that (-)-epigallocatechin gallate (EGCG), the main flavonoid present in green tea, dose-dependently inhibited MPO-mediated HOCl formation in vitro (chlorinating activities of MPO: 50.2 ± 5.7% for 20 μM EGCG versus 100 ± 5.6% for control, P < 0.01). UV-vis spectral and docking studies indicated that EGCG bound to the active site (heme) of MPO and resulted in the accumulation of compound II, which was unable to produce HOCl. This flavonoid also effectively inhibited HOCl generation in activated neutrophils (HOCl formation: 65.0 ± 5.6% for 20 μM EGCG versus 100 ± 6.2% for control, P < 0.01) without influencing MPO and Nox2 release and superoxide formation, suggesting that EGCG specifically inhibited MPO but not NADPH oxidase activity in activated neutrophils. Moreover, EGCG inhibited MPO (or neutrophil)-mediated HOCl formation in human umbilical vein endothelial cells (HUVEC) culture and accordingly protected HUVEC from MPO (or neutrophil)-induced injury (P < 0.05, all cases), although it did not induce cytotoxicity to HUVEC (P > 0.05, all cases). Our results indicate that dietary EGCG is an effective and specific inhibitor of MPO activity and may participate in the regulation of immune responses at inflammatory sites.

Nanoparticles Coated with Neutrophil Membranes Can Effectively Treat Cancer Metastasis

The dissemination, seeding, and colonization of circulating tumor cells (CTCs) serve as the root of distant metastasis. As a key step in the early stage of metastasis formation, colonization of CTCs in the (pre-)metastatic niche appears to be a valuable target. Evidence showed that inflammatory neutrophils possess both a CTC- and niche-targeting property by the intrinsic cell adhesion molecules on neutrophils. Inspired by this mechanism, we developed a nanosize neutrophil-mimicking drug delivery system (NM-NP) by coating neutrophils membranes on the surface of poly(latic-co-glycolic acid) nanoparticles (NPs). The membrane-associated protein cocktails on neutrophils membrane were mostly translocated to the surface of NM-NP via a nondisruptive approach, and the biobinding activity of neutrophils was highly preserved. Compared with uncoated NP, NM-NP exhibited enhanced cellular association in 4T1 cell models under shear flow in vitro, much higher CTC-capture efficiency in vivo, and improved homing to the premetastatic niche. Following loading with carfilzomib, a second generation of proteasome inhibitor, the NM-NP-based nanoformulation (NM-NP-CFZ) selectively depleted CTCs in the blood, prevented early metastasis and potentially inhibited the progress of already-formed metastasis. Our NP design can neutralize CTCs in the circulation and inhibit the formation of a metastatic niche.

Simultaneous comprehensive multiplex autoantibody analysis for rapidly progressive glomerulonephritis

Rapidly progressive glomerulonephritis (RPGN) is mainly caused by anti-glomerular basement membrane (GBM) antibody-mediated glomerulonephritis, immune-complex or anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides and leads to rapid loss of renal function. Detection of ANCA and autoantibodies (autoAbs) to GBM and dsDNA enables early diagnosis and appropriate treatment of RPGN aiding in preventing end-stage renal disease.Determination of ANCA on neutrophils (ANCA) as well as autoAbs to myeloperoxidase (MPO-ANCA), proteinase 3 (PR3-ANCA), GBM, and dsDNA was performed by the novel multiplex CytoBead technology combining cell- and microbead-based autoAb analyses by automated indirect immunofluorescence (IIF). Forty patients with granulomatosis with polyangiitis (GPA), 48 with microscopic polyangiitis (MPA), 2 with eosinophilic GPA, 42 with systemic lupus erythematosus (SLE), 43 with Goodpasture syndrome (GPS), 57 with infectious diseases (INF), and 55 healthy subjects (HS) were analyzed and findings compared with classical single testing.The CytoBead assay revealed for GPA, MPA, GPS, and SLE the following diagnostic sensitivities and for HS and INF the corresponding specificities: PR3-ANCA, 85.0% and 100.0%; MPO-ANCA, 77.1% and 99.1%; anti-GBM autoAb, 88.4% and 96.4%; anti-dsDNA autoAb, 83.3% and 97.3%; ANCA, 91.1% and 99.1%, respectively. Agreement with classical enzyme-linked immunosorbent assay and IIF was very good for anti-GBM autoAb, MPO-ANCA, PR3-ANCA, and ANCA, respectively. Anti-dsDNA autoAb comparative analysis demonstrated fair agreement only and a significant difference (P = 0.0001).The CytoBead technology provides a unique multiplex reaction environment for simultaneous RPGN-specific autoAb testing. CytoBead RPGN assay is a promising alternative to time-consuming single parameter analysis and, thus, is well suited for emergency situations.

Neutrophil proteomic analysis reveals the participation of antioxidant enzymes, motility and ribosomal proteins in the prevention of ischemic effects by preconditioning

Intestinal ischemia and reperfusion injury are widely used models, which result into tissue injury and multiple organ failure also observed after trauma and surgery. Ischemic preconditioning (IPC) preceding ischemia and reperfusion (IR) was shown to attenuate this injury and has a potential therapeutic application; however the exact underlying mechanism is not clear. Neutrophils play an important role in the mechanism of injuries caused by ischemia and reperfusion while IPC led to a decrease in neutrophil stimulation and activation. The effect of preconditioning on the neutrophil proteome is unclear. Proteomic analysis has been ratified as an appropriate tool for studying complex systems. In order to evaluate the effect of IPC preceding 45min of ischemia on the proteome of neutrophils we used Wistar rats divided in four experimental groups: Control, sham laparotomy, intestinal ischemia reperfusion and ischemic preconditioning. After neutrophil separation, proteins were extracted, trypsin digested and the resulting peptides were iTRAQ labeled followed by HILIC fractionation and nLC-MS/MS analysis. After database searches, normalization and statistical analysis our proteomic analysis resulted in the identification of 2437 protein groups that were assigned to five different clusters based on the relative abundance profiles among the experimental groups. The clustering followed by statistical analysis led to the identification of significantly up and downregulated proteins in IR and IPC. Cluster based KEGG pathways analysis revealed up- regulation of actin cytoskeleton, metabolism, Fc gamma R mediated phagocytosis, chemokine signaling, focal adhesion and leukocyte transendothelial migration whereas downregulation in ribosome, spliceosome, RNA transport, protein processing in endoplasmic reticulum and proteasome, after intestinal ischemic preconditioning. Furthermore, enzyme prediction analysis revealed the regulation of some important antioxidant enzymes and having their role in reactive oxygen species production. To our knowledge, this work describes the most comprehensive and detailed quantitative proteomic study of the neutrophil showing the beneficial role of ischemic preconditioning and its effects on the neutrophil proteome. This data will be helpful to understand the effect of underlying protective mechanisms modulating the role of PMNs after IPC and provide a trustworthy basis for future studies.

BIOLOGICAL SIGNIFICANCE

Preconditioning is a relevant strategy to overcome clinical implications from ischemia and reperfusion. Such implications have the neutrophil as a major player. Although many publications describe specific biochemical and physiological roles of the neutrophil in such conditions, there is no report of a proteomic study providing a broader view of this scenario. Here we describe a group of proteins significantly regulated by ischemia and reperfusion being such regulation prevented by preconditioning. Such finding may provide relevant information for a deeper understanding of the mechanisms involved, as well as serve as basis for future biomarker or drug target assays.

THE DETERMINATION OF CORRELATION LINKAGES BETWEEN LEVEL OF REACTIVE OXYGEN SPECIES, CONTENTS OF NEUTROPHILES AND BLOOD GAS COMPOSITION IN EXPERIMENTAL ACUTE LUNG INJURY

Acute lung injury (ALI) remains a major cause of acute respiratory failure and death of patients. Despite the achievements at the current stage in treatment, morbidity and mortality of ALI remain high. However, a deeper understanding of the pathogenetic links of ALI, identifying of the predictors that positively or negatively influence on the course of the syndrome, the correlation between some pathogenetic mechanisms will improve therapeutic strategies for patients with ALI, which makes the actuality of this study. The aim of the research was to detect additional pathogenetic mechanisms of the acute lung injury development in rats based on a comparative analysis of the correlations between the level of reactive oxygen species in blood and bronchoalveolar lavage, contents of neutrophils and blood gas composition. The experiments were performed on 54 white nonlinear mature male rats 200-220g in weight. The animals were divided into 5 groups: the 1st - control group (n=6), the 2nd - animals affected by hydrochloric acid for 2 hours (n=12), the 3rd - animals affected by hydrochloric acid for 6 hours (n=12), the 4th - animals affected by hydrochloric acid for 12 hours (n=12), the 5th - animals affected by hydrochloric acid for 24 hours (n=12). Correlation analysis was performed between all the studied indices. Coefficient of linear correlation (r) and its fidelity (p) was calculated that was accordingly denoted in the tables (correlation matrices). The correlation coefficient was significant at p<0.05. Conducted correlative analysis showed that the level of ROS in neutrophils of blood in rats with modeled ALI had a high negative correlative linkage with pH of arterial blood in 2nd and 3rd experimental groups. Conducted correlative analysis of data in BAL showed that the level of ROS in neutrophils in rats with modeled ALI had a strong positive correlative relationship with the number of white blood cells in 3-rd, 4-th and 5-th experimental groups and positive correlative relationship with the absolute number of neutrophils in the same experimental group. Consequently, the main manifestation of acute lung injury is the development of hypoxia and respiratory acidosis that is caused by the violation of gases diffusion in the alveoli. On this background non-specific inflammatory reaction is developed at lung microvessels level with violation of lung homeostasis, which is iniciated by neutrophils' activation, which are producing ROS.