Update on Neutrophil Function in Severe Inflammation

Neutrophils are main players in the effector phase of the host defense against micro-organisms and have a major role in the innate immune response. Neutrophils show phenotypic heterogeneity and functional flexibility, which highlight their importance in regulation of immune function. However, neutrophils can play a dual role and besides their antimicrobial function, deregulation of neutrophils and their hyperactivity can lead to tissue damage in severe inflammation or trauma. Neutrophils also have an important role in the modulation of the immune system in response to severe injury and trauma. In this review we will provide an overview of the current understanding of neutrophil subpopulations and their function during and post-infection and discuss the possible mechanisms of immune modulation by neutrophils in severe inflammation

Cigarette smoke regulates the expression of TLR4 and IL-8 production by human macrophages

<p>Abstract</p> <p>Background</p> <p>Toll-like receptors (TLRs) are present on monocytes and alveolar macrophages that form the first line of defense against inhaled particles. The importance of those cells in the pathophysiology of chronic obstructive pulmonary disease (COPD) has well been documented. Cigarette smoke contains high concentration of oxidants which can stimulate immune cells to produce reactive oxygen species, cytokines and chemokines.</p> <p>Methods</p> <p>In this study, we evaluated the effects of cigarette smoke medium (CSM) on TLR4 expression and interleukin (IL)-8 production by human macrophages investigating the involvement of ROS.</p> <p>Results and Discussion</p> <p>TLR4 surface expression was downregulated on short term exposure (1 h) of CSM. The downregulation could be explained by internalization of the TLR4 and the upregulation by an increase in TLR4 mRNA. IL-8 mRNA and protein were also increased by CSM. CSM stimulation increased intracellular ROS-production and decreased glutathione (GSH) levels. The modulation of TLR4 mRNA and surface receptors expression, IRAK activation, IκB-α degradation, IL-8 mRNA and protein, GSH depletion and ROS production were all prevented by antioxidants such as N-acetyl-L-cysteine (NAC).</p> <p>Conclusion</p> <p>TLR4 may be involved in the pathogenesis of lung emphysema and oxidative stress and seems to be a crucial contributor in lung inflammation.</p

The analysis of exosomal micro-RNAs in peripheral blood mononuclear cell-derived macrophages after infection with bacillus Calmette–Guérin by RNA sequencing

AbstractObjective/BackgroundTuberculosis (TB) is a major global threat to human health, especially in low-income countries. The diagnosis of TB is challenging because of the limitations of specificity and sensitivity with the current diagnostics. Novel, selective biomarkers for TB would be of great practical value. Exosomes are bioactive vesicles with 30–100nm in diameter, which are secreted from almost all cell types and are found in virtually every human body fluid. Exosomes transport micro-RNAs (miRNAs), which are post-transcriptional regulators of gene expression, around the body and allow miRNAs to modulate biological pathways in target cells. Our aim was to investigate the potential of exosomal miRNAs as biomarkers by examining their release from human monocyte-derived macrophages (MDMs) after infection with Mycobacterium using miRNA sequencing.MethodsHuman monocytes were obtained from blood and driven to an MDM phenotype using standard protocols. MDMs were infected with Mycobacterium bovis Bacillus Calmette–Guérin (BCG) or left uninfected as control. Exosomes were collected 72 h postinfection from the cell culture medium and subjected to RNA isolation. Small RNA libraries were constructed and RNA sequencing performed. The raw reads were filtered to eliminate adaptor and primer sequences, and the sequences in FASTQ format were run against the mature human miRNA sequences available in miRBase using BLAST software using a Linux operating system. Micro-RNAs were identified using E=0.01 or 1.ResultsInfection of MDMs with BCG lead to the release of a number of exosomal miRNAs. These mainly consisted with Let-7 family members, miR-155, miR-146a, miR-145, and miR-21 all of which were predicted to target important immune-related genes and pathways.ConclusionThis study provides evidence for the release of specific miRNAs from BCG-infected MDMs. These results need to be confirmed and the presence of this panel of miRNAs tested in the blood of patients to determine their selectivity and specificity as a diagnostic in patients with TB

Galactooligosaccharides and 2′-fucosyllactose can directly suppress growth of specific pathogenic microbes and affect phagocytosis of neutrophils

Objectives: Non-digestible oligosaccharides such as milk oligosaccharides (MOS) can regulate and influence immune function. As an example, galactooligosaccharides (GOS), and 2′-fucosyllactose (2′-FL; a specific human MOS) regulate immune development and functionality. Staphylococcus aureus (SA) and Pseudomonas aeruginosa (PA), both serious pathogens, can cause severe and life-threatening infections. The aim of this study was to examine the effects of GOS and 2′-FL on bacterial growth and on polymorphonuclear (PMN) phagocytosis. Methods: PMNs were isolated from heparinized whole human blood before treatment/incubation with GOS (0.0625–10%), 2′-FL (0.5–2.5%) and/or GOS combined with 2′-FL (GOS 10%/2′-FL 2.5%; GOS 0.0625%/2′-FL 0.5%) and incubation with green florescent protein (GFP)-labeled SA or PA for 60 h. GFP-relative fluorescent units (GFP-RFU) was measured ≤60 h using a plate reader. Bacterial lag time was determined by the time to onset of exponential bacterial fluorescence/growth alone or after co-culture of bacteria and PMN. Viable bacterial colony-forming units (CFUs) were determined after 60 h. Results: SA and PA growth lag time was suppressed by co-incubation with GOS in a concentration-dependent manner. This was significant for both SA and PA at concentrations >2.5% GOS (P ≤ 0.05 for both SA and PA) but only for SA at 1% GOS (P ≤ 0.05). 1.5% 2′-FL significantly suppressed the lag time of SA growth (P ≤ 0.05) and was effective against SA and PA at 2.5% (P ≤ 0.01 and P ≤ 0.01, respectively). GOS (10%, 5%) and 2.5% 2′-FL significantly decreased SA and PA bacterial growth/CFUs (P ≤ 0.05). Conclusion: The data suggests that both GOS and 2′-FL can suppress growth of serious pathogens and enhance phagocytosis

Evaluation of myeloid-derived suppressor cells in the blood of Iranian COVID-19 patients

The cytokine storm and lymphopenia are reported in coronavirus disease 2019 (COVID-19). Myeloid-derived suppressive cells (MDSCs) exist in two different forms, granulocyte (G-MDSCs) and monocytic (M-MDSCs), that both suppress T-cell function. In COVID-19, the role of chemokines such as interleukin (IL)-8 in recruiting MDSCs is unclear. A recent report has correlated IL-8 and MDSCs with poor clinical outcomes in melanoma patients. In the current study, we evaluated the frequency of MDSCs and their correlation with serum IL-8 levels in severe COVID-19 patients from Iran. Thirty-seven severe patients (8 on ventilation, 29 without ventilation), thirteen moderate COVID-19 patients, and eight healthy subjects participated in this study between 10th April 2020 and 9th March 2021. Clinical and biochemical features, serum, and whole blood were obtained. CD14, CD15, CD11b, and HLA-DR expression on MDSCs was measured by flow cytometry. COVID-19 patients compared to healthy subjects had a greater frequency of M-MDSCs (12.7±13.3% vs 0.19±0.20%,), G-MDSCs (15.8±12.6% vs 0.35±0.40%,) and total-MDSCs (27.5±17.3% vs 0.55±0.41%,). M-MDSC (16.8±15.8% vs 5.4±4.8%,) and total-MDSC (33.3±18.5% vs 17.3±13.3%) frequency was higher in non- ventilated compared to moderate COVID-19 subjects. Serum IL-8 levels were higher in patients with COVID-19 than in normal healthy subjects (6.4±7.8 vs. 0.10±00 pg/mL). Ventilated patients (15.7±6.7 pg/mL), non-ventilated patients (5.7±2.7 pg/mL) and moderate patients (2.8±3.0 pg/mL) had significantly different levels of IL-8.  A negative correlation was found between the frequency of G-MDSCs and the international normalized ratio (INR) test (r=-0.39), and between the frequency of total-MDSCs and oxygen saturation (%) (r=-0.39). COVID-19 patients with severe non-ventilated disease had the highest levels of M-MDSCs. In addition to systemic MDSCs, lung, serum IL-8, and other inflammatory biomarkers should be measured

A synbiotic mixture of Bifidobacterium breve M16-V, oligosaccharides and pectin, enhances Short Chain Fatty Acid production and improves lung health in a preclinical model for pulmonary neutrophilia

IntroductionPulmonary neutrophilia is a hallmark of numerous airway diseases including Chronic Obstructive Pulmonary Disease (COPD), Neutrophilic asthma, Acute Lung Injury (ALI), Acute Respiratory Distress Syndrome (ARDS) and COVID-19. The aim of the current study was to investigate the effect of dietary interventions on lung health in context of pulmonary neutrophilia.MethodsMale BALB/cByJ mice received 7 intra-nasal doses of either a vehicle or lipopolysaccharides (LPS). To study the effect of nutritional interventions they received 16 intra-gastric doses of either a vehicle (PBS) or the following supplements (1) probiotic Bifidobacterium breve (B. breve) M16-V; (2) a prebiotic fiber mixture of short-chain galacto-oligosaccharides, long-chain fructo-oligosaccharides, and low-viscosity pectin in a 9:1:2 ratio (scGOS/lcFOS/lvPectin); and (3) A synbiotic combination B. breve M16-V and scGOS/lcFOS/lvPectin. Parameters for lung health included lung function, lung morphology and lung inflammation. Parameters for systemic immunomodulation included levels of fecal short chain fatty acids and regulatory T cells.ResultsThe synbiotic supplement protected against the LPS induced decline in lung function (35% improved lung resistance at baseline p = 0.0002 and 25% at peak challenge, p = 0.0002), provided a significant relief from pulmonary neutrophilia (40.7% less neutrophils, p &lt; 0.01) and improved the pulmonary neutrophil-to-lymphocyte ratio (NLR) by 55.3% (p = 0.0033). Supplements did not impact lung morphology in this specific experiment. LPS applied to the upper airways induced less fecal SCFAs production compared to mice that received PBS. The production of acetic acid between day −5 and day 16 was increased in all unchallenged mice (PBS-PBS p = 0.0003; PBS-Pro p &lt; 0.0001; PBS-Pre, p = 0.0045; PBS-Syn, p = 0.0005) which upon LPS challenge was only observed in mice that received the synbiotic mixture of B. breve M16-V and GOS:FOS:lvPectin (p = 0.0003). A moderate correlation was found for butyric acid and lung function parameters and a weak correlation was found between acetic acid, butyric acid and propionic acid concentrations and NLR.ConclusionThis study suggests bidirectional gut lung cross-talk in a mouse model for pulmonary neutrophilia. Neutrophilic lung inflammation coexisted with attenuated levels of fecal SCFA. The beneficial effects of the synbiotic mixture of B. breve M16-V and GOS:FOS:lvPectin on lung health associated with enhanced levels of SCFAs

Exhaled nitric oxide is not a biomarker for idiopathic pulmonary arterial hypertension or for treatment efficacy

BACKGROUND: Idiopathic pulmonary arterial hypertension (IPAH) is a fatal illness. Despite many improvements in the treatment of these patients, there is no unique prognostic variable available to track these patients. The aim of this study was to evaluate the association between fractional exhaled nitric oxide (FeNO) levels, as a noninvasive biomarker, with disease severity and treatment outcome. METHODS: Thirty-six patients (29 women and 7 men, mean age 38.4 ± 11.3 years) with IPAH referred to the outpatient's clinic of Masih Daneshvari Hospital, Tehran, Iran, were enrolled into this pilot observational study. Echocardiography, six-minute walking test (6MWT), FeNO, brain natriuretic peptide (BNP) levels and the functional class of patients was assessed before patients started treatment. Assessments were repeated after three months. 30 healthy non-IPAH subjects were recruited as control subjects. RESULTS: There was no significant difference in FeNO levels at baseline between patients with IPAH and subjects in the control group. There was also no significant increase in FeNO levels during the three months of treatment and levels did not correlate with other disease measures. In contrast, other markers of disease severity were correlated with treatment effect over the three months. CONCLUSION: FeNO levels are a poor non-invasive measure of IPAH severity and of treatment response in patients in this pilot study

Immunologic finding of disseminated granuloma reaction in patients with Mycobacterium tuberculosis and sarcoidosis

AbstractIntroductionNecrotizing sarcoid granulomatosis (NSG) is a rare syndrome with unknown etiology. The disease is frequently confused with sarcoidosis and other granulomatous diseases. Diagnosis is made based on typical histologic criteria. No specific laboratory finding can confirm NSG diagnosis. The gender ratio of women to men has been reported as being as high as 4:1 and has a good prognosis.Methods and resultsIn this report, the clinical and genetic features were surveyed of a 36-year-old male with extra-pulmonary NSG with unique manifestations, such as inguinal mass with positive smear and negative culture for the infection of Mycobacterium tuberculosis (MTB), which was not responsive to the first-line TB treatment and was characterized as a multidrug-resistant (MDR) tuberculosis (TB). Later on, he was admitted for the MDR cure, and he did not react to the gold standard of MDR treatment. Finally, he presented with a huge lymphoid granuloma with massive ascites that was diagnosed as an NSG by IHC. He cured well with prednisolone and all symptoms of the disease were gone. At the hospitalization time, all laboratory experiments were well planned, such as a workup for the detection of defects of loop IL-12/IFN-γ, HLA-DR typing, and immunologic workup by flow-cytometry analysis.ConclusionThis is the first case report from patients with unique features of NSG combined with MTB

Procalcitonin and Proinflammatory Cytokines in Early Diagnosis of Bacterial Infections after Bronchoscopy

BACKGROUND: Fiberoptic bronchoscopy (FOB) guided bronchoalveolar lavage (BAL) remains as the chief diagnostic tool in respiratory disorders. 1.2-16% of patients frequently experience fever after bronchoscopy. To exclude the need for multiple antibiotic prescribing in patients with post-bronchoscopy fever, the presence of the self-limiting inflammatory responses should be excluded. AIM: The current study was conducted to test the serum of patients undergoing bronchoscopy for some proinflammatory cytokines including Tumor Necrosis Factor-alpha (TNF-ɑ), Interleukin-1beta (IL-1β), Interleukin-8 (IL-8) and Interleukin-6 (IL-6) and the value of Procalcitonin (PCT). MATERIAL AND METHODS: Current case-control study was conducted at the National Research Institute of Tuberculosis and Lung Disease in Iran. Nineteen patients (48.72%) that attended with a reasonable sign for a diagnostic bronchoscopy from January 2016 to December 2017 were included in the case group. The control group consisted of 20 patients who underwent a simple bronchoscopy and without FOB-BAL. The laboratory findings for PCT concentrations and cytokine levels in the three serum samples (before FOB-BAL (t0), after 6 hr. (t1), and at 24 hr. past (t2) FOB-BAL) were compared between two groups. RESULTS: The frequency of post-bronchoscopy fever was 5.12, and the prevalence of post-bronchoscopy infectious fever was 2.56%. PCT level was considerably higher in the patient with a confirmed bacterial infection when compared to other participants (p-value &lt; 0. 05). Interestingly, IL-8 level in the bacterial infection proven fever patient was higher than in other patients (p &lt; 0.001). IL-8 levels displayed a specificity of 72.7% and a sensitivity of 100%, at the threshold point of 5.820 pg/ml. PCT levels had a specificity of 84% and a sensitivity of 81%, at the threshold point of 0.5 ng/ml. CONCLUSION: The present findings show that in patients with fever after bronchoscopy, PCT levels and IL-8 levels are valuable indicators for antibiotic therapy, proving adequate proof for bacterial infection. The current findings also illustrate that to monitor the serum levels of PCT and proinflammatory cytokines in the patients undergoing FOB-BAL, the best time is the 24-hour postoperative bronchoscopy