Human resistin promotes neutrophil proinflammatory activation and neutrophil extracellular trap formation and increases severity of acute lung injury

Adiponectin, resistin, interleukin-4 and TGF-β2 levels in treatment resistant schizophrenia patients

BACKGROUND

The aim of the present study was to measure adiponectin, resistin, interleukin-4 and TGF-β levels in first episode, treatment resistant patients with schizophrenia.

METHODS

In total, fifty-three treatment-resistant patients were included in the study. In subgroups of these patients, we measured Interleukin-4 (IL-4), Tumor Growth Factor-β2 (TGF-β2), adiponectin and resistin levels at three different timepoints: in the drug-naïve state, after two rounds of treatment with different antipsychotic drugs for a total of 16 weeks and, after clozapine treatment for 12 weeks.

RESULTS

TGF-β2 and adiponectin levels decreased after treatment with olanzapine and risperidone, while resistin and IL-4 levels did not differ significantly.Comparing the levels of the aforementioned cytokines before the initiation and after clozapine treatment, we found an even greater decrease in adiponectin levels while resistin and IL-4 levels significantly increased and TGF-β2 levels did not differ significantly.

CONCLUSIONS

We report elevated resistin and IL-4 levels and decreased adiponectin levels in first-episode, treatment resistant schizophrenia patients after clozapine treatment. These findings may be at least partly due to the anti-inflammatory action of clozapine, although sub-clinical metabolic disturbances may also have played a role as far as resistin and adiponectin are concerned. In a subgroup of these patients we report reduced TGF-β2 and adiponectin levels after two unsuccessful trials with risperidone and olanzapine comparing them with the ones of the same subgroup in the drug-naïve phase.

Immunological roles for resistin and related adipokines in obesity-associated tumors

Rationale Obesity is an independent risk factor for the occurrence and development of tumors. Obesity is influenced by signaling of adipokines, which are secreted factors from adipocytes and resident immune cells within adipose tissues that mediate lipid metabolism. More recently, adipokines have been implicated in chronic inflammation as well as in tumor formation and growth. Among them, resistin has received increasing attention in research related to the growth and expansion of solid tumors and hematological cancers through various signaling pathways. Objective and findings We reviewed the physiological, biochemical, and immune functions of adipose tissue, with a focus on the structure and expression of resistin and adipokines within multiple adipose cell types, their signaling pathways and putative effects on tumor cells, as well as their in vivo regulation. Current evidence indicates that adipokines such as resistin act as pro-inflammatory factors to stimulate immune cells which, in turn, promotes tumor angiogenesis, connective tissue proliferation, and matrix fibrosis. Concurrently, in states of metabolic dysfunction and lipotoxicity in obese individuals, the numbers and functions of immune cells are compromised, leading to an immunosuppressive environment that fosters tumor cell survival and weak cancer immune monitoring. Conclusion Adipokines such as resistin are important to the development of obesity-related tumors. Clarifying the roles for obesity-related factors in immune regulation and tumor progression may lead to the discovery of novel anti-tumor strategies for targeting obesity factors such as resistin to limit tumor growth and manage obesity, or both.

Effects of early treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) on the bronchoalveolar lavage proteome and oxylipids during bovine respiratory syncytial virus (BRSV) infection

Non-steroidal anti-inflammatory drugs (NSAID) are not recommended for use against pneumonia in humans, but are commonly utilised against bovine respiratory disease. This study aimed to determine if the use of NSAIDs in the early phase of bovine respiratory syncytial virus (BRSV)-infection limits pulmonary inflammation. Four to nine-week old calves were infected with BRSV by aerosol and were treated with either meloxicam intravenously on day (D)4 (n = 5, MEL), acetylsalicylat-DL-lysin intravenously on D4 and D5 (n = 5, ASA), or were left untreated as controls (n = 5, CTR). Clinical signs were monitored daily until necropsy on D7, BRSV-RNA was detected in nasal swabs and bronchoalveolar lavage (BAL) by RT-qPCR, inflammatory cells and proteins were identified in BAL by cytology and label-free quantitative mass spectrometry-based proteomics, respectively, and oxylipids were quantified in BAL and plasma by liquid chromatography tandem mass spectrometry with triple quadrupole mass detectors. The calves developed mild to moderate signs of respiratory disease and, with the exception of one MEL-treated and one ASA-treated calf, limited lung lesions. None of the treatments had a significant effect on virus replication, clinical signs or lung lesion extent. Relative to controls, both treatments initially induced a downregulation of proteins in BAL. Immunoglobulin (Ig)-related proteins, such as the Ig kappa and lambda locus and the joining chain of IgA and IgM, were downregulated in MEL-treated calves compared to controls. In addition, meloxicam induced an increased neutrophil influx in BAL in response to BRSV, possibly related to a reduction in plasma prostaglandin, and to a downregulation of The Liver X Receptor/ Retinoid X Receptor (LXR/RXR), the Farnesoid X Receptor (FXR)/RXR and the 24-Dehydrocholesterol Reductase (DHC24) signalling pathways in the lung. The risk of NSAIDs to increase neutrophil activity during stimulation with BRSV or other toll-like receptor 4 agonists needs to be investigated further. Since augmented neutrophil responses can be detrimental, the results of the present study do not support the use of NSAIDs to prevent the clinical expression of BRSV-infection.

Plasma levels of myeloperoxidase and resistin independently predict mortality in dialysis patients

BACKGROUND

In patients with kidney failure (KF) undergoing dialysis, neutrophils are dysfunctionally activated. Such chronic activation does not correspond to increased protection against infections and is thought to cause direct vascular damage accounting for the higher incidence of cardiovascular (CV) events. We hypothesized that circulating levels of neutrophil degranulation products (i.e. myeloperoxidase (MPO) and resistin) can predict overall and CV-specific mortality in dialysis patients.

METHODS

MPO and resistin levels were assessed in plasma samples from n = 1182 dialysis patients who were followed-up for median 2.9 years (IQR: 1.7-4.2).

RESULTS

Patients were 65 ± 14 (SD) years old and 36 % women. Median value of MPO and resistin were 78 ng/mL (IQR: 54 - 123) and 72 ng/mL (IQR: 46 - 110), respectively. MPO and resistin levels correlated with biomarkers of organ damage, nutritional status and inflammation. Both MPO and resistin levels predicted all-cause mortality even after adjustment for traditional risk factors and inflammation, nutritional and KF-related indexes (MPO, HRfor 1 ln unit increase: 1.26, 95 %CI 1.11 - 1.42, P < 0.001; Resistin, HRfor 1 ln unit increase: 1.25, 95 %CI 1.09 - 1.44, P = 0.001). Similarly, their predictive ability held true also for CV death (MPO, HRfor 1 ln unit increase: 1.19, 95 %CI 1.01 - 1.41, P = 0.04; Resistin, HRfor 1 ln unit increase: 1.29, 95 %CI 1.07 - 1.56, P = 0.007).

CONCLUSION

Plasma levels of MPO and resistin correlate with prospective overall and CV-specific mortality risk in KF patients undergoing dialysis and might be useful prognostic tools. Mediators of inflammation may be potential target to improve survival of those patients.

Immunological characteristics of bronchoalveolar lavage fluid and blood across connective tissue disease-associated interstitial lung diseases

Interstitial lung disease (ILD) is a serious complication of connective tissue diseases (CTDs). The heterogeneity of ILDs reflects differences in pathogenesis among diseases. This study aimed to clarify the characteristics of CTD-ILDs via a detailed analysis of the bronchoalveolar lavage fluid (BALF) and blood immune cells. BALF and blood samples were collected from 39 Japanese patients with newly diagnosed ILD: five patients with Sjögren's syndrome (SS), eight patients with dermatomyositis (DM), six patients with rheumatoid arthritis (RA), six patients with systemic sclerosis, four patients with anti-neutrophil cytoplasmic antibody-associated vasculitis, and 10 patients with idiopathic interstitial pneumonia. We performed single-cell RNA sequencing to analyze the gene expression profiles in these patients' immune cells. In patients with SS, B cells in the BALF were increased and genes associated with the innate and acquired immunity were enriched in both the BALF and blood. In contrast, patients with DM showed an upregulation of genes associated with viral infection in both the BALF and blood. In patients with RA, neutrophils in the BALF tended to increase, and their gene expression patterns changed towards inflammation. These disease-specific characteristics may help us understand the pathogenesis for each disease and discover potential biomarkers.

The role of adipokines in the pathogenesis of psoriasis - a focus on resistin, omentin-1 and vaspin

BACKGROUND

Psoriasis is a chronic immune-mediated skin condition with several types of manifestation, including psoriatic arthritis. In recent years, studies have demonstrated multiple molecules and mechanisms that play important roles in the pathophysiology of psoriasis. Studies have been conducted to determine the role of adipokines, bioactive peptides secreted by the adipose tissue, in the pathogenesis of inflammatory diseases. These studies have shown that adipokines are dysregulated in psoriasis and their abnormal expression profile could contribute to the inflammatory mechanisms observed in psoriasis.

AREAS COVERED

In this review, we discuss the immunomodulatory features of resistin, omentin-1, and vaspin, and discuss their potential involvement in the pathogenesis of psoriasis.

EXPERT OPINION

The adipokines resistin, omentin, and vaspin appear to be promising therapeutic targets in psoriasis. It is important to seek to block the action of resistin, either by blocking its receptors or by blocking its systemic effects with antibodies. In the case of omentin and vaspin, substances that are receptor mimetics of these adipokines should be sought and studies conducted of their analogues for the treatment of psoriasis. To introduce these therapies into clinical practice, multicentre clinical trials are required to confirm their efficacy and safety after initial studies in animal models.

Neutrophil Migration Is Mediated by VLA-6 in the Inflamed Adipose Tissue

Adipose tissue, well known for its endocrine function, plays an immunological role in the body. The inflamed adipose tissue under LPS-induced systemic inflammation is characterized by the dominance of pro-inflammatory immune cells, particularly neutrophils. Although migration of macrophages toward damaged or dead adipocytes to form a crown-like structure in inflamed adipose tissue has been revealed, the neutrophilic interaction with adipocytes or the extracellular matrix remains unknown. Here, we demonstrated the involvement of adhesion molecules, particularly integrin α6β1, of neutrophils in adipocytes or the extracellular matrix of inflamed adipose tissue interaction. These results suggest that disrupting the adhesion between adipose tissue components and neutrophils may govern the accumulation of excessive neutrophils in inflamed tissues, a prerequisite in developing anti-inflammatory therapeutics by inhibiting inflammatory immune cells.

Single-cell profiling of bronchoalveolar cells reveals a Th17 signature in neutrophilic severe equine asthma

Severe equine asthma (SEA) is a complex respiratory condition characterized by chronic airway inflammation. It shares many clinical and pathological features with human neutrophilic asthma, making it a valuable model for studying this condition. However, the immune mechanisms driving SEA have remained elusive. Although SEA has been primarily associated with a Th2 response, there have also been reports of Th1, Th17, or mixed-mediated responses. To uncover the elusive immune mechanisms driving SEA, we performed single-cell mRNA sequencing (scRNA-seq) on cryopreserved bronchoalveolar cells from 11 Warmblood horses, 5 controls and 6 with SEA. We identified six major cell types, including B cells, T cells, monocytes-macrophages, dendritic cells, neutrophils, and mast cells. All cell types exhibited significant heterogeneity, with previously identified and novel cell subtypes. Notably, we observed monocyte-lymphocyte complexes and detected a robust Th17 signature in SEA, with CXCL13 upregulation in intermediate monocytes. Asthmatic horses exhibited expansion of the B-cell population, Th17 polarization of the T-cell populations, and dysregulation of genes associated with T-cell function. Neutrophils demonstrated enhanced migratory capacity and heightened aptitude for neutrophil extracellular trap formation. These findings provide compelling evidence for a predominant Th17 immune response in neutrophilic SEA, driven by dysregulation of monocyte and T-cell genes. The dysregulated genes identified through scRNA-seq have potential as biomarkers and therapeutic targets for SEA and provide insights into human neutrophilic asthma.

Resistin - A Plausible Therapeutic Target in the Pathogenesis of Psoriasis

Resistin, a cytokine hormone predominantly secreted by adipose tissue, is elevated in various metabolic disorders such as obesity, type 2 diabetes, and cardiovascular disease. In addition to its involvement in metabolic regulation, resistin has been implicated in the pathogenesis of psoriasis, a chronic inflammatory skin disorder. Numerous studies have reported increased resistin levels in psoriatic skin lesions, suggesting a possible association between resistin and psoriasis. Recent studies have suggested the potential involvement of resistin in the development and progression of certain cancers. Resistin is overexpressed in breast, colorectal, and gastric cancers. This suggests that it may play a role in the development of these cancers, possibly by inducing inflammation and cell growth. The link between resistin and cancer raises the possibility of shared underlying mechanisms driving the pathogenesis of psoriasis. Chronic inflammation, one such mechanism, is a hallmark of psoriasis and cancer. Further research is needed to fully understand the relationship between resistin and psoriasis. Identifying potential therapeutic targets is crucial for effective management of psoriasis. By doing so, we may be able to develop more effective treatment options for individuals living with psoriasis and ultimately improve their quality of life. Ultimately, a more comprehensive understanding of the mechanisms underlying the impact of resistin on psoriasis is essential for advancing our knowledge and finding new ways to treat and manage this challenging condition.

Predictive value of adipokines for the severity of acute pancreatitis: a meta-analysis

BACKGROUND

Severe acute pancreatitis (SAP) is a dangerous condition with a high mortality rate. Many studies have found an association between adipokines and the development of SAP, but the results are controversial. Therefore, we performed a meta-analysis of the association of inflammatory adipokines with SAP.

METHODS

We screened PubMed, EMBASE, Web of Science and Cochrane Library for articles on adipokines and SAP published before July 20, 2023. The quality of the literature was assessed using QUADAS criteria. Standardized mean differences (SMD) with 95% confidence intervals (CI) were calculated to assess the combined effect. Subgroup analysis, sensitivity analysis and publication bias tests were also performed on the information obtained.

RESULT

Fifteen eligible studies included 1332 patients with acute pancreatitis (AP). Pooled analysis showed that patients with SAP had significantly higher serum levels of resistin (SMD = 0.78, 95% CI:0.37 to 1.19, z = 3.75, P = 0.000). The difference in leptin and adiponectin levels between SAP and mild acute pancreatitis (MAP) patients were not significant (SMD = 0.30, 95% CI: -0.08 to 0.68, z = 1.53, P = 0.127 and SMD = 0.11, 95% CI: -0.17 to 0.40, z = 0.80, P = 0.425, respectively). In patients with SAP, visfatin levels were not significantly different from that in patients with MAP (SMD = 1.20, 95% CI: -0.48 to 2.88, z = 1.40, P = 0.162).

CONCLUSION

Elevated levels of resistin are associated with the development of SAP. Resistin may serve as biomarker for SAP and has promise as therapeutic target.

Modeling the Effects of IL-1β-mediated Inflammation During Ex Vivo Lung Perfusion Using a Split Human Donor Model

BACKGROUND

The association between interleukin-1β (IL-1β) concentrations during ex vivo lung perfusion (EVLP) with donor organ quality and post-lung transplant outcome has been demonstrated in several studies. The mechanism underlying IL-1β-mediated donor lung injury was investigated using a paired single-lung EVLP model.

METHODS

Human lung pairs were dissected into individual lungs and perfused on identical separate EVLP circuits, with one lung from each pair receiving a bolus of IL-1β. Fluorescently labeled human neutrophils isolated from a healthy volunteer were infused into both circuits and quantified in perfusate at regular timepoints. Perfusates and tissues were subsequently analyzed, with perfusates also used in functional assays.

RESULTS

Neutrophil numbers were significantly lower in perfusate samples collected from the IL-1β-stimulated lungs consistent with increased neutrophil adhesion ( P = 0.042). Stimulated lungs gained significantly more weight than controls ( P = 0.046), which correlated with soluble intercellular adhesion molecule-1 (R 2 = 0.71, P = 0.0043) and von-Willebrand factor (R 2 = 0.39, P = 0.040) in perfusate. RNA expression patterns for inflammatory genes were differentially regulated via IL-1β. Blockade of IL-1β significantly reduced neutrophil adhesion in vitro ( P = 0.025).

CONCLUSION

These data illustrate the proinflammatory functions of IL-1β in the context of EVLP, suggesting this pathway may be susceptible to therapeutic modulation before transplantation.

Inflammatory response after out-of-hospital cardiac arrest-Impact on outcome and organ failure development

BACKGROUND

Post-cardiac arrest syndrome that occurs in out-of-hospital cardiac arrest (OHCA) patients is characterized by inflammatory response. We conducted a scoping review of current evidence regarding several inflammatory markers' usefulness for assessment of patient outcome and illness severity. We also discuss the proposed underlying mechanisms leading to inflammatory response after OHCA.

METHODS

We searched the MEDLINE, PubMed Central, Cochrane CENTRAL and Web of Science Core Collection databases with the following search terms: ("inflammation" OR "cytokines") AND "out-of-hospital cardiac arrest." Each inflammatory marker found was combined with "out-of-hospital cardiac arrest" using "AND" to find further relevant studies. We included original studies measuring inflammatory markers in adult OHCA patients that assessed their prognostic capabilities for mortality, neurological outcome, or organ failure severity.

RESULTS

Fifty-nine studies met the inclusion criteria, covering in total 65 different markers. Interleukin-6 (IL-6), procalcitonin (PCT) and C-reactive protein (CRP) were the most studied markers, and they were associated with poor outcomes in 13/15, 13/14 and 11/17 studies, respectively. Based on area under the receiver operating characteristic curve (AUC) value, the time point of best discriminatory capacity for poor outcome was ICU admission for IL-6 (median AUC 0.78, range 0.71-0.98) and day one after OHCA for PCT (median AUC 0.84, range 0.61-0.98). Seven studies reported AUCs for CRP (range 0.52-0.76) with no measurement time point being superior to others. The association of IL-6 and PCT with outcome appeared stronger in studies with more severely ill patients. Studies reported conflicting results regarding each marker's association with organ failure severity.

CONCLUSION

Inflammatory markers are potentially useful for early risk stratification after OHCA. PCT and IL-6 have moderate prognostic value during the first 24 h of the ICU stay. Predictive accuracy appears to be associated with the study overall event rate.

Chronic unpredictable mild stress promotes atherosclerosis via adipose tissue dysfunction in ApoE-/- mice

Background

Chronic unpredictable mild stress (CUMS) has been shown to exacerbate atherosclerosis, but the underlying mechanism remains unknown. Adipose tissue is an energy storage organ and the largest endocrine organ in the human body, playing a key role in the development of cardiovascular disease. In this research, it was hypothesized that CUMS may exacerbate the development of atherosclerosis by inducing the hypertrophy and dysfunction of white adipocytes.

Methods

The CUMS-induced atherosclerosis model was developed in Western diet-fed apolipoprotein E (ApoE)-/- mice. White adipose tissue (WAT), serum, aortic root, and the brachiocephalic trunk were collected and tested after 12 weeks of CUMS development. The mouse model of CUMS was evaluated for depression-like behavior using the open field test (OFT) and the elevated plus maze (EPM) test. Enzyme-linked immunosorbent assay (ELISA) was conducted to detect serum noradrenaline and urine adrenaline protein levels. Serological assays were used to detect serum low-density lipoprotein (LDL), high-density lipoprotein (HDL), total cholesterol (TC), and free fatty acid (FFA) concentrations. Hematoxylin and eosin (H&E) staining and oil red O were used to detect atherosclerotic plaque area, lipid deposition, and adipocyte size. The mRNA levels of genes related to aberrant adipose tissue function were determined using real-time PCR. Immunofluorescence assay and western blotting were conducted to examine the expression of proteins in the adipose tissue samples.

Results

CUMS aggravated vascular atherosclerotic lesions in ApoE-/- mice. It decreased body weight while increasing the percentage of WAT. The serological results indicated that the concentration of HDL decreased in CUMS mice. Notably, adipocyte hypertrophy increased, whereas the mRNA levels of Pparg and its target genes (Slc2a4 (encodes for GLUT4), Adipoq, and Plin1) decreased. Further investigation revealed that CUMS increased subcutaneous inguinal WAT (iWAT) lipid synthesis and adipocyte inflammation while decreasing lipid hydrolysis and the expression of HDL-associated protein ApoA-I. Moreover, CUMS aggravated insulin resistance in mice and inhibited the insulin pathway in iWAT.

Conclusions

These findings indicated that CUMS induces adipose tissue dysfunction via a mechanism that leads to dyslipidemia, increased inflammation, and insulin resistance in the body, thereby exacerbating atherosclerosis. Notably, CUMS that is involved in decreasing the expression of HDL-associated proteins in adipose tissue may be a crucial link between adipose hypertrophy and advanced atherosclerosis. This study reveals a novel mechanism via which CUMS exacerbates atherosclerosis from the novel perspective of abnormal adipose function and identifies a novel potential therapeutic target for this disease.

Recombinant human DNase-I improves acute respiratory distress syndrome via neutrophil extracellular trap degradation

BACKGROUND

Respiratory failure is the primary cause of death in patients with COVID-19, whereas coagulopathy is associated with excessive inflammation and multiorgan failure. Neutrophil extracellular traps (NETs) may exacerbate inflammation and provide a scaffold for thrombus formation.

OBJECTIVES

The goal of this study was to determine whether degradation of NETs by recombinant human DNase-I (rhDNase), a safe, Food and Drug Administration-approved drug, reduces excessive inflammation, reverses aberrant coagulation, and improves pulmonary perfusion after experimental acute respiratory distress syndrome (ARDS).

METHODS

Intranasal poly(I:C), a synthetic double-stranded RNA, was administered to adult mice for 3 consecutive days to simulate a viral infection, and these subjects were randomized to treatment arms, which received either an intravenous placebo or rhDNase. The effects of rhDNase on immune activation, platelet aggregation, and coagulation were assessed in mice and donor human blood.

RESULTS

NETs were observed in bronchoalveolar lavage fluid and within regions of hypoxic lung tissue after experimental ARDS. The administration of rhDNase mitigated peribronchiolar, perivascular, and interstitial inflammation induced by poly(I:C). In parallel, rhDNase degraded NETs, attenuated platelet-NET aggregates, reduced platelet activation, and normalized the clotting time to improve regional perfusion, as observed using gross morphology, histology, and microcomputed tomographic imaging in mice. Similarly, rhDNase reduced NETs and attenuated platelet activation in human blood.

CONCLUSION

NETs exacerbate inflammation and promote aberrant coagulation by providing a scaffold for aggregated platelets after experimental ARDS. Intravenous administration of rhDNase degrades NETs and attenuates coagulopathy in ARDS, providing a promising translational approach to improve pulmonary structure and function after ARDS.

Influence of Pre-Pregnancy Obesity on Carbohydrate and Lipid Metabolism with Selected Adipokines in the Maternal and Fetal Compartment

A higher body mass index (BMI) before pregnancy is associated with an increased risk of maternal and perinatal complications. This study aimed to analyze selected parameters of carbohydrate and lipid metabolism, including adipokines, in obese pre-pregnant women, and their influence on the birth weight of newborns.

MATERIALS AND METHODS

The study group (O) consisted of 34 pregnant women with higher BMI (obese) before pregnancy. The control group (C) was 27 pregnant women with target BMI and physiological pregnancy. The BMI index: body weight [kg]/(height [m]² was assessed on the first obstetrical visit. The research material was the serum of pregnant women collected in the third trimester of pregnancy and umbilical cord blood collected immediately after delivery. Selected parameters of carbohydrate and lipid metabolism and adipokines were determined.

RESULTS

There were no statistically significant differences between the study group and the control group concerning the concentrations of insulin, glucose, VLDL, adiponectin, TNF-α, HOMA-IR, as well as LDH and cholesterol in maternal blood serum and umbilical cord blood serum. Total cholesterol and HDL in both maternal blood serum and umbilical cord blood were statistically significantly lower than those in the control group. The concentration of triglycerides (TG) and resistin in the blood serum of obese mothers were higher than those in the control group (p < 0.05). However, no statistically significant differences were found between the two groups regarding the concentrations of TG and resistin in the umbilical cord blood. The concentration of LDL cholesterol in the umbilical blood serum in the obese group was statistically significantly lower than that in the control group. The concentration of leptin in maternal blood serum and umbilical cord blood serum in the study group was statistically significantly higher than that in the control group.

CONCLUSIONS

Pregestational obesity does not substantially affect the basic parameters of carbohydrate metabolism in pregnant women, but it disturbs the lipid profile, which is manifested by a significant increase in triglycerides and a decrease in the level of HDL cholesterol in the serum. Preexisting obesity increases the concentration of leptin and resistin in the serum of pregnant women, which may be caused by the increased volume of adipose tissue. The concentrations of leptin and resistin in the blood of pregnant women correlate positively, and the concentrations of adiponectin and TNF-α negatively correlate with pre-pregnancy BMI values. There is a positive correlation between the concentration of leptin in the serum of umbilical cord blood and the birth weight of the newborn, which suggests that this parameter contributes to the pathomechanism of macrosomia.

Human Resistin Induces Cardiac Dysfunction in Pulmonary Hypertension

Background Cardiac failure is the primary cause of death in most patients with pulmonary arterial hypertension (PH). As pleiotropic cytokines, human resistin (Hresistin) and its rodent homolog, resistin-like molecule α, are mechanistically critical to pulmonary vascular remodeling in PH. However, it is still unclear whether activation of these resistin-like molecules can directly cause PH-associated cardiac dysfunction and remodeling. Methods and Results In this study, we detected Hresistin protein in right ventricular (RV) tissue of patients with PH and elevated resistin-like molecule expression in RV tissues of rodents with RV hypertrophy and failure. In a humanized mouse model, cardiac-specific Hresistin overexpression was sufficient to cause cardiac dysfunction and remodeling. Dilated hearts exhibited reduced force development and decreased intracellular Ca2+ transients. In the RV tissues overexpressing Hresistin, the impaired contractility was associated with the suppression of protein kinase A and AMP-activated protein kinase. Mechanistically, Hresistin activation triggered the inflammation mediated by signaling of the key damage-associated molecular pattern molecule high-mobility group box 1, and subsequently induced pro-proliferative Ki67 in RV tissues of the transgenic mice. Intriguingly, an anti-Hresistin human antibody that we generated protected the myocardium from hypertrophy and failure in the rodent PH models. Conclusions Our data indicate that Hresistin is expressed in heart tissues and plays a role in the development of RV dysfunction and maladaptive remodeling through its immunoregulatory activities. Targeting this signaling to modulate cardiac inflammation may offer a promising strategy to treat PH-associated RV hypertrophy and failure in humans.

THE ROLE OF OBESITY AND PLASMA ADIPOCYTOKINES IN IMMUNE DYSREGULATION IN SEPSIS PATIENTS

Introduction: The dysregulated immune response in sepsis is highly variable, ranging from hyperinflammation to immunoparalysis. Obesity is associated with the release of inflammatory mediators from adipose tissue, known as adipocytokines, causing a chronic inflammatory state. Perhaps counterintuitively, obesity is also associated with lower mortality in sepsis patients. We investigated the association between obesity, circulating adipocytokine concentrations, immune dysregulation, and outcome in sepsis patients. Methods In this secondary analysis of a prospective study, plasma concentrations of the adipocytokines leptin, adiponectin, and resistin were assessed in 167 patients at diagnosis of sepsis due to pneumonia, bacteremia, or acute cholangitis. Adipocytokines were compared between patients with normal weight (body mass index [BMI], 18.5-24.9 kg/m 2 ; n = 67), overweight (BMI, 25.0-29.9 kg/m 2 ; n = 56), and obesity (BMI ≥30 kg/m 2 ; n = 42), as well as between immunological endotypes: hyperinflammation (n = 40), immunoparalysis (n = 62), and unclassified (n = 55). Results: Higher circulating concentrations of leptin were observed in patients with obesity compared with patients with normal weight ( P = 0.008) and overweight ( P = 0.02), whereas adiponectin and resistin plasma concentrations were not different ( P = 0.08 and P = 0.85, respectively). Resistin concentrations were associated with immunological endotypes, with the highest levels found in hyperinflammatory patients ( P < 0.001). Furthermore, resistin concentrations were predictive for 28-day mortality (adjusted odds ratio, 1.03 per 10 ng/mL; P = 0.04). These associations were not found for leptin and adiponectin. Conclusion: Obesity and BMI-related adipocytokines are not related to the development of a hyperactive or suppressed immune response as defined by ferritin and mHLA-DR expression in sepsis patients. Although resistin is related to the immune response and an increased risk of adverse clinical outcomes, these associations are similar in patients with normal weight, overweight, and obesity. This implies that the relationship between resistin and clinical outcome is likely driven by the inflammatory response and not by obesity itself. Taken together, although there exists a strong association between inflammation and sepsis mortality, our results do not point toward a role for obesity and BMI-related adipocytokines in immune dysregulation in sepsis patients.

Association between circulating resistin levels and thyroid dysfunction: A systematic review and meta-analysis

Background

As a product of adipose tissue, resistin exceeds other adipokines in its role in regulating appetite, energy expenditure, insulin sensitivity, inflammation, and immunity, similar to thyroid hormones. This study aimed to evaluate the association between resistin levels and thyroid dysfunction and to explore variations in circulating resistin levels before and after treatment for thyroid dysfunction.

Methods

This study was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analysis statement. A comprehensive search of PubMed, Embase, and Cochrane databases was conducted until June 15, 2022, with no start date restriction, according to the preregistered protocol (PROSPERO-CRD42022336617). RevMan version 5.4 and R software package version 4.2.0 were used for statistical analyses.

Results

Fourteen studies with 1716 participants were included in this study. The findings of the meta-analysis confirmed that the resistin levels of patients with thyroid dysfunction were significantly higher than those of the euthyroid function control group (mean difference [MD] = 2.11, 95% confidence interval [CI] = 1.11-3.11, P < 0.00001). Furthermore, the resistin levels of patients with hyperthyroidism (MD = 3.23, 95% CI = 0.68-5.79, P = 0.01) and subclinical hypoidism (MD = 1.37, 95% CI = 0.31-2.42, P = 0.01) were significantly higher than those of euthyroid controls. The resistin levels of patients with thyroid dysfunction after treatment were significantly lower than those before treatment (MD = 1.00, 95% CI = 0.34-1.65, P = 0.003), especially in patients with hyperthyroidism (MD = 2.16, 95% CI = 1.00-3.32, P = 0.0003). Correlation analysis confirmed a positive correlation between resistin levels and free triiodothyronine (FT3) levels in patients with thyroid dysfunction (r = 0.27578, P = 0.001).

Conclusions

Our meta-analysis demonstrates that resistin levels are significantly higher in patients with thyroid dysfunction, and the resistin levels after treatment in patients with thyroid dysfunction are significantly lower than those before treatment. Correlation analysis shows a positive correlation between resistin levels and FT3 levels in patients with thyroid dysfunction.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022336617.

Dietary Risk Factors and Eating Behaviors in Peripheral Arterial Disease (PAD)

Dietary risk factors play a fundamental role in the prevention and progression of atherosclerosis and PAD (Peripheral Arterial Disease). The impact of nutrition, however, defined as the process of taking in food and using it for growth, metabolism and repair, remains undefined with regard to PAD. This article describes the interplay between nutrition and the development/progression of PAD. We reviewed 688 articles, including key articles, narrative and systematic reviews, meta-analyses and clinical studies. We analyzed the interaction between nutrition and PAD predictors, and subsequently created four descriptive tables to summarize the relationship between PAD, dietary risk factors and outcomes. We comprehensively reviewed the role of well-studied diets (Mediterranean, vegetarian/vegan, low-carbohydrate ketogenic and intermittent fasting diet) and prevalent eating behaviors (emotional and binge eating, night eating and sleeping disorders, anorexia, bulimia, skipping meals, home cooking and fast/ultra-processed food consumption) on the traditional risk factors of PAD. Moreover, we analyzed the interplay between PAD and nutritional status, nutrients, dietary patterns and eating habits. Dietary patterns and eating disorders affect the development and progression of PAD, as well as its disabling complications including major adverse cardiovascular events (MACE) and major adverse limb events (MALE). Nutrition and dietary risk factor modification are important targets to reduce the risk of PAD as well as the subsequent development of MACE and MALE.

Interplay Between the Immune and Endocrine Systems in the Lung: Implications for TB Susceptibility

The role of the endocrine system on the immune response, especially in the lung, remains poorly understood. Hormones play a crucial role in the development, homeostasis, metabolism, and response to the environment of cells and tissues. Major infectious and metabolic diseases, such as tuberculosis and diabetes, continue to converge, necessitating the development of a clearer understanding of the immune and endocrine interactions that occur in the lung. Research in bacterial respiratory infections is at a critical point, where the limitations in identifying and developing antibiotics is becoming more profound. Hormone receptors on alveolar and immune cells may provide a plethora of targets for host-directed therapy. This review discusses the interactions between the immune and endocrine systems in the lung. We describe hormone receptors currently identified in the lungs, focusing on the effect hormones have on the pulmonary immune response. Altered endocrine responses in the lung affect the balance between pro- and anti-inflammatory immune responses and play a role in the response to infection in the lung. While some hormones, such as leptin, resistin and lipocalin-2 promote pro-inflammatory responses and immune cell infiltration, others including adiponectin and ghrelin reduce inflammation and promote anti-inflammatory cell responses. Furthermore, type 2 diabetes as a major endocrine disease presents with altered immune responses leading to susceptibility to lung infections, such as tuberculosis. A better understanding of these interactions will expand our knowledge of the mechanisms at play in susceptibility to infectious diseases and may reveal opportunities for the development of host-directed therapies.

Resistin production does not affect outcomes in a mouse model of acute surgical sepsis

Introduction

Because of the strong correlation between the blood concentration of circulating resistin and the illness severity of septic patients, resistin has been proposed as a mediator of sepsis pathophysiology. In vitro data indicate that human resistin directly impairs neutrophil migration and intracellular bacterial killing, although the significance of these findings in vivo remain unclear.

Objective

The objectives of the present study were: (1) to validate the expression of human resistin in a clinically relevant, murine model of surgical sepsis, (2) to assess how sepsis-induced changes in resistin correlate with markers of infection and organ dysfunction, and (3) to investigate whether the expression of human resistin alters immune function or disease outcomes in vivo.

Methods

107 male, C57BL/6 mice transgenic for the human resistin gene and its promoter elements (Retn^+/−/−, or Retn+) were generated on a Retn^−/− (mouse resistin knockout, or Rko) background. Outcomes were compared between age-matched transgenic and knockout mice. Acute sepsis was defined as the initial 24 h following cecal ligation and puncture (CLP). Physiologic and laboratory parameters correlating to the human Sequential Organ Failure Assessment (SOFA) Score were measured in mice, and innate immune cell number/function in the blood and peritoneal cavity were assessed.

Results

CLP significantly increased circulating levels of human resistin. The severity of sepsis-induced leukopenia was comparable between Retn+ and Rko mice. Resistin was associated with increased production of neutrophil reactive oxygen species, a decrease in circulating neutrophils at 6 h and an increase in peritoneal Ly6C^hi monocytes at 6 h and 24 h post-sepsis. However, intraperitoneal bacterial growth, organ dysfunction and mouse survival did not differ with resistin production in septic mice.

Significance

Ex vivo resistin-induced impairment of neutrophil function do not appear to translate to increased sepsis severity or poorer outcomes in vivo following CLP.

Effect of insulin resistance on lung function in asthmatic children

OBJECTIVES

Insulin resistance may be associated with impaired lung function. The objective of this study was to examine the relationship between insulin resistance and lung function in asthmatic children.

METHODS

We performed a cross-sectional study on asthmatic children aged 6-18 years at Tertiary Care Center, India. Fasting serum glucose and insulin levels were analyzed to calculate the homeostatic model assessment of insulin resistance (HOMA-IR) in 90 children. Lung function tests were performed. Spearman correlation was used to assess the relationship between insulin resistance and lung function. Linear regression was done to adjust the potential confounders.

RESULTS

Insulin resistance was present in 15.5% of patients. We found a statistically significant inverse relationship between HOMA-IR and spirometric parameters such as forced expiratory volume in 1 s/forced vital capacity ratio and forced expiratory flow between 25 and 75% on Spearman correlation. However, adjusted regression for age, gender, and body mass index showed no significant association of lung function parameters with HOMA-IR.

CONCLUSIONS

Insulin resistance may be considered for the decline in lung function in asthmatic children.

Hepatic Lipid Metabolism Disorder and Atherosclerosis

Lipid metabolism disorder plays a fundamental role in the pathogenesis of atherosclerosis. As the largest metabolic organ of the human body, liver has a key role in lipid metabolism by influencing fat production, fat decomposition, and the intake and secretion of serum lipoproteins. Numerous clinical and experimental studies have indicated that the dysfunction of hepatic lipid metabolism is closely tied to the onset of atherosclerosis. However, the identity and functional role of hepatic lipid metabolism responsible for these associations remain unknown. This review presented that cholesterol synthesis, cholesterol transport, and the metabolism of triglyceride, lipoproteins, and fatty acids are all associated with hepatic lipid metabolism and atherosclerosis. Moreover, we also discussed the roles of gut microbiota, inflammatory response, and oxidative stress in the pathological association between hepatic lipid metabolism and atherosclerosis. These significant evidences support strongly that hepatic lipid metabolism disorders may increase the risk of atherosclerosis.

Hexavalent chromium inhibits the formation of neutrophil extracellular traps and promotes the apoptosis of neutrophils via AMPK signaling pathway

As the most common heavy metal pollutant, hexavalent chromium [Cr(VI)] has caused serious environmental pollution and health damage. Although the toxic effect of Cr(VI) has been widely studied, and oxidative stress has been confirmed to be the main mechanism of its cytotoxicity, the toxicity of Cr(VI) to human immune system remains to be elucidated. Neutrophil extracellular traps (NETs) participate in the innate immune response, and the release of NETs is considered to be the most important part of the extracellular killing mechanism. We demonstrated in this study that Cr(VI) inhibited the formation of NETs in rat peripheral blood and induced neutrophils apoptosis by inhibiting the AMP-activated protein kinase (AMPK) signaling pathway. Cr(VI)-induced inhibition of NETs was accompanied by down-regulated myeloperoxidase (MPO)/Histones-3 (H3) protein expressions and decreased NETs-associated intracellular and extracellular DNA levels in the neutrophils. Metformin (Met), as an AMPK activator, triggered autophagy and thus alleviated the inhibitory effect of Cr(VI) on NETs. At the same time, Met can reduce the intracellular reactive oxygen species (ROS) level by activating the AMPK/nuclear factor erythroid-2 related factor 2 (Nrf2) signaling pathway, thus alleviating Cr(VI)-induced neutrophils apoptosis. In conclusion, this study elucidated the mechanism of Cr(VI)-induced neutrophils toxicity and the role of AMPK as a key regulatory signal, which could provide valuable experimental basis for the prevention and treatment of related diseases in Cr(VI)-exposed populations.

Obesity and severe coronavirus disease 2019: molecular mechanisms, paths forward, and therapeutic opportunities

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) appears to have higher pathogenicity among patients with obesity. Obesity, termed as body mass index greater than 30 kg/m2, has now been demonstrated to be important comorbidity for disease severity during coronavirus disease 2019 (COVID-19) pandemic and associated with adverse events. Unraveling mechanisms behind this phenomenon can assist scientists, clinicians, and policymakers in responding appropriately to the COVID-19 pandemic. In this review, we systemically delineated the potential mechanistic links between obesity and worsening COVID-19 from altered physiology, underlying diseases, metabolism, immunity, cytokine storm, and thrombosis. Problematic ventilation caused by obesity and preexisting medical disorders exacerbate organ dysfunction for patients with obesity. Chronic metabolic disorders, including dyslipidemia, hyperglycemia, vitamin D deficiency, and polymorphisms of metabolism-related genes in obesity, probably aid SARS-CoV-2 intrusion and impair antiviral responses. Obesity-induced inadequate antiviral immunity (interferon, natural killer cells, invariant natural killer T cell, dendritic cell, T cells, B cell) at the early stage of SARS-CoV-2 infection leads to delayed viral elimination, increased viral load, and expedited viral mutation. Cytokine storm, with the defective antiviral immunity, probably contributes to tissue damage and pathological progression, resulting in severe symptoms and poor prognosis. The prothrombotic state, driven in large part by endothelial dysfunction, platelet hyperactivation, hypercoagulability, and impaired fibrinolysis in obesity, also increases the risk of severe COVID-19. These mechanisms in the susceptibility to severe condition also open the possibility for host-directed therapies in population with obesity. By bridging work done in these fields, researchers can gain a holistic view of the paths forward and therapeutic opportunities to break the vicious cycle of obesity and its devastating complications in the next emerging pandemic.

Resistin, a Novel Host Defense Peptide of Innate Immunity

Resistin, a cysteine-rich protein, expressed in adipocytes, was initially proposed as a link between obesity and diabetes in mice. In humans, resistin is considered to be a pro-inflammatory molecule expressed in immune cells, which plays a regulatory role in many chronic inflammatory diseases, metabolic diseases, infectious diseases, and cancers. However, increasing evidence shows that resistin functions as a host defense peptide of innate immunity, in terms of its wide-spectrum anti-microbial activity, modulation of immunity, and limitation of microbial product-induced inflammation. To date, the understanding of resistin participating in host defense mechanism is still limited. The review aims to summarize current knowledge about the biological properties, functions, and related mechanisms of resistin in host defense, which provides new insights into the pleiotropic biological function of resistin and yields promising strategies for developing new antimicrobial therapeutic agents.

AMPK activates Parkin independent autophagy and improves post sepsis immune defense against secondary bacterial lung infections

Metabolic and bioenergetic plasticity of immune cells is essential for optimal responses to bacterial infections. AMPK and Parkin ubiquitin ligase are known to regulate mitochondrial quality control mitophagy that prevents unwanted inflammatory responses. However, it is not known if this evolutionarily conserved mechanism has been coopted by the host immune defense to eradicate bacterial pathogens and influence post-sepsis immunosuppression. Parkin, AMPK levels, and the effects of AMPK activators were investigated in human leukocytes from sepsis survivors as well as wild type and Park2^−/− murine macrophages. In vivo, the impact of AMPK and Parkin was determined in mice subjected to polymicrobial intra-abdominal sepsis and secondary lung bacterial infections. Mice were treated with metformin during established immunosuppression. We showed that bacteria and mitochondria share mechanisms of autophagic killing/clearance triggered by sentinel events that involve depolarization of mitochondria and recruitment of Parkin in macrophages. Parkin-deficient mice/macrophages fail to form phagolysosomes and kill bacteria. This impairment of host defense is seen in the context of sepsis-induced immunosuppression with decreased levels of Parkin. AMPK activators, including metformin, stimulate Parkin-independent autophagy and bacterial killing in leukocytes from post-shock patients and in lungs of sepsis-immunosuppressed mice. Our results support a dual role of Parkin and AMPK in the clearance of dysfunctional mitochondria and killing of pathogenic bacteria, and explain the immunosuppressive phenotype associated Parkin and AMPK deficiency. AMPK activation appeared to be a crucial therapeutic target for the macrophage immunosuppressive phenotype and to reduce severity of secondary bacterial lung infections and respiratory failure.

Adiposity and Interstitial Lung Abnormalities in Community-Dwelling Adults: The MESA Cohort Study

BACKGROUND

Obesity is associated with restrictive ventilatory defects and a faster rate of decline in FVC. This association is not exclusively mediated by mechanical factors and may reflect direct pulmonary injury by adipose-derived mediators.

RESEARCH QUESTION

Is adipose tissue involved in the pathogenesis of interstitial lung disease (ILD)?

STUDY DESIGN AND METHODS

We evaluated the association of CT measures of pericardial, abdominal visceral, and abdominal subcutaneous adipose tissue with high-attenuation areas (HAAs) and interstitial lung abnormalities (ILAs) in a large multicenter cohort study of community-dwelling adults, using multivariable-adjusted models. We secondarily evaluated the association of adipose depot size with FVC and biomarkers of obesity and inflammation.

RESULTS

In fully adjusted models, every doubling in pericardial adipose tissue volume was associated with a 63.4-unit increase in HAA (95% CI, 55.5-71.3), 20% increased odds of ILA (95% CI, -2% to 50%), and a 5.5% decrease in percent predicted FVC (95% CI, -6.8% to -4.3%). IL-6 levels accounted for 8% of the association between pericardial adipose tissue and HAA. Every doubling in visceral adipose tissue area was associated with a 41.5-unit increase in HAA (95% CI, 28.3-54.7), 30% increased odds of ILA (95% CI, -10% to 80%), and a 5.4% decrease in percent predicted FVC (95% CI, -6.6% to -4.3%). IL-6 and leptin accounted for 17% and 18%, respectively, of the association between visceral adipose tissue and HAA.

INTERPRETATION

Greater amounts of pericardial and abdominal visceral adipose tissue were associated with CT measures of early lung injury and lower FVC in a cohort of community-dwelling adults. Adipose tissue may represent a modifiable risk factor for ILD.

Comparative analysis of inflammatory signature profiles in eosinophilic and noneosinophilic chronic rhinosinusitis with nasal polyposis

Chronic rhinosinusitis with nasal polyposis (CRSwNP) represents a heterogeneous disorder that can be classified into either eosinophilic or noneosinophilic endotypes. However, the immunological mechanisms of each remain unclear. The purpose of the present study was to compare and analyze inflammatory signatures of eosinophilic CRSwNP (ECRSwNP) and noneosinophilic CRSwNP (NECRSwNP). Cytokine antibody array was used to identify inflammatory mediators that were differentially expressed among ECRSwNP, NECRSwNP, and control groups. Then, bioinformatics approaches were conducted to explore biological functions and signaling pathways. In addition, pairwise correlation analyses were performed among differential levels of inflammatory mediators and tissue eosinophil infiltration. The results showed that nine mediators were significantly up-regulated in ECRSwNP, including eotaxin-2, eotaxin-3, CCL18, IL-4, IL-5, IL-10, IL-12p70, IL-13, and IL-15. Bioinformatics analysis indicated that these mediators were mainly enriched in leukocyte chemotaxis and proliferation, JAK-STAT cascade, asthma, and Th1 and Th2 cell differentiation. Furthermore, seven mediators were identified to be significantly up-regulated in NECRSwNP, including CCL20, resistin, transforming growth factor (TGF)-β2, triggering receptor expressed on myeloid cells 1 (TREM-1), CD14, glucocorticoid-induced tumor necrosis factor receptor related protein (GITR), and lipocalin-2. These mediators were closely associated with LPS responses, neutrophil chemotaxis and migration, and IL-17 signaling pathway. In addition, pairwise correlation analyses indicated that differential levels of inflammatory mediators in ECRSwNP and NECRSwNP were broadly correlated with each other and with tissue eosinophil infiltration. In conclusion, we found that ECRSwNP and NECRSwNP exhibited different patterns of inflammatory signatures. These findings may provide further insights into heterogeneity of CRSwNP.

The pathophysiological role of adipokines in the development of bronchial asthma combined with obesity

The combined course of bronchial asthma (BA) and obesity is one of the urgent medical and social problems that requires a comprehensive and careful study in connection with a decrease in the quality of life of such patients, an increase in the frequency, duration of hospitalization and a high economic burden for the state as a whole. The relationship between BA and obesity is now confirmed by numerous studies, at the same time, despite the variability of the proposed mechanisms of pathogenetic effects of obesity on asthma, metabolic aspects of the relationship of these diseases need further study. Adipose tissue hormones are responsible for the energy homeostasis of the body therefore, excessive accumulation of adipose tissue is accompanied by the development of an imbalance in metabolic processes in various organs and tissues. Due to the emergence of new scientific data on the role and function of adipokines in the body, metabolic effects of adipokines are considered in the focus of their pathophysiological association with obesity and asthma. This literary review highlights the current understanding of the role of metabolic effects of the most studied adipokines (resistin, retinol-binding protein, leptin and adiponectin) in the development of obesity and BA. Gender and age-dependent features of adipokine levels in BA and obesity are described. Data on the confirmed role of adiponectin and leptin in the progression of BA combined with obesity are presented. It has been shown that the role of resistin and retinol-binding protein in the development of BA combined with obesity has not been studied. It is demonstrated that further study of metabolic activity of adipokines in BA is an actual and perspective direction of researches which will allow to develop new diagnostic and therapeutic strategies in patients with BA with obesity.

A neutrophil activation signature predicts critical illness and mortality in COVID-19

Pathologic immune hyperactivation is emerging as a key feature of critical illness in COVID-19, but the mechanisms involved remain poorly understood. We carried out proteomic profiling of plasma from cross-sectional and longitudinal cohorts of hospitalized patients with COVID-19 and analyzed clinical data from our health system database of more than 3300 patients. Using a machine learning algorithm, we identified a prominent signature of neutrophil activation, including resistin, lipocalin-2, hepatocyte growth factor, interleukin-8, and granulocyte colony-stimulating factor, which were the strongest predictors of critical illness. Evidence of neutrophil activation was present on the first day of hospitalization in patients who would only later require transfer to the intensive care unit, thus preceding the onset of critical illness and predicting increased mortality. In the health system database, early elevations in developing and mature neutrophil counts also predicted higher mortality rates. Altogether, these data suggest a central role for neutrophil activation in the pathogenesis of severe COVID-19 and identify molecular markers that distinguish patients at risk of future clinical decompensation.

Neutrophil dysfunction in bronchiectasis: an emerging role for immunometabolism

Bronchiectasis is a heterogenous disease with multiple underlying causes. The pathophysiology is poorly understood but neutrophilic inflammation and dysfunctional killing of pathogens is believed to be key. There are, however, no licensed therapies for bronchiectasis that directly target neutrophilic inflammation. In this review, we discuss our current understanding of neutrophil dysfunction and therapeutic targeting in bronchiectasis. Immunometabolic reprogramming, a process through which inflammation changes inflammatory cell behaviour by altering intracellular metabolic pathways, is increasingly recognised across multiple inflammatory and autoimmune diseases. Here, we show evidence that much of the neutrophil dysfunction observed in bronchiectasis is consistent with immunometabolic reprogramming. Previous attempts at developing therapies targeting neutrophils have focused on reducing neutrophil numbers, resulting in increased frequency of infections. New approaches are needed and we propose that targeting metabolism could theoretically reverse neutrophil dysfunction and dysregulated inflammation. As an exemplar, 5' adenosine monophosphate (AMP)-activated protein kinase (AMPK) activation has already been shown to reverse phagocytic dysfunction and neutrophil extracellular trap (NET) formation in models of pulmonary disease. AMPK modulates multiple metabolic pathways, including glycolysis which is critical for energy generation in neutrophils. AMPK activators can reverse metabolic reprogramming and are already in clinical use and/or development. We propose the need for a new immunomodulatory approach, rather than an anti-inflammatory approach, to enhance bacterial clearance and reduce bronchiectasis disease severity.

Adipokine-Modulated Immunological Homeostasis Shapes the Pathophysiology of Inflammatory Bowel Disease

Inflammatory colon diseases, which are a global health concern, include a variety of gastrointestinal tract disorders, such as inflammatory bowel disease and colon cancer. The pathogenesis of these colon disorders involves immune alterations with the pronounced infiltration of innate and adaptive immune cells into the intestines and the augmented expression of mucosal pro-inflammatory cytokines stimulated by commensal microbiota. Epidemiological studies during the past half century have shown that the proportion of obese people in a population is associated with the incidence and pathogenesis of gastrointestinal tract disorders. The advancement of understanding of the immunological basis of colon disease has shown that adipocyte-derived biologically active substances (adipokines) modulate the role of innate and adaptive immune cells in the progress of intestinal inflammation. The biomedical significance in immunological homeostasis of adipokines, including adiponectin, leptin, apelin and resistin, is clear. In this review, we highlight the existing literature on the effect and contribution of adipokines to the regulation of immunological homeostasis in inflammatory colon diseases and discuss their crucial roles in disease etiology and pathogenesis, as well as the implications of these results for new therapies in these disorders.

The role of resistin and myeloperoxidase in severe sepsis and septic shock: Results from the ALBIOS trial

BACKGROUND

Inflammatory biomarkers are useful in detecting patients with sepsis. The prognostic role of resistin and myeloperoxidase (MPO) has been investigated in sepsis.

MATERIALS AND METHODS

Plasma resistin and MPO were measured on days 1, 2 and 7 in 957 patients enrolled in the Albumin Italian Outcome Sepsis (ALBIOS) trial. The association between resistin and MPO levels on day 1, 2 and 7 and 90-day mortality was assessed.

RESULTS

Plasma resistin and MPO concentrations were higher at day 1 and decreased until day 7. Both biomarkers were positively correlated with each other and with physiological parameters. Higher levels of resistin and MPO on day 1 were associated with the development of new organ failures. Patients experiencing death at 90 days showed higher levels of resistin and MPO compared with survivors. At day 1, only MPO in the 4th quartile (Q4), but not resistin, was found to predict 90-day death (adjusted hazard ratio [aHR] 1.55 vs Q1). At day 2, resistin in the Q3 and Q4 predicted a > 40% increase in mortality as also did MPO in the Q4. On day 7, Q4 resistin was able to predict 90-day mortality, while all quartiles of MPO were not.

CONCLUSIONS

High levels of MPO, but not of resistin, on day 1 were able to predict 90-day mortality. These findings may either suggest that early hyper-activation of neutrophils is detrimental in patients with sepsis or reflect the burden of the inflammatory process caused by sepsis. Further studies are warranted to deepen these aspects (ALBIOS ClinicalTrials.gov Identifier: NCT00707122).

A neutrophil activation signature predicts critical illness and mortality in COVID-19

Pathologic immune hyperactivation is emerging as a key feature of critical illness in COVID-19, but the mechanisms involved remain poorly understood. We carried out proteomic profiling of plasma from cross-sectional and longitudinal cohorts of hospitalized patients with COVID-19 and analyzed clinical data from our health system database of over 3,300 patients. Using a machine learning algorithm, we identified a prominent signature of neutrophil activation, including resistin, lipocalin-2, HGF, IL-8, and G-CSF, as the strongest predictors of critical illness. Neutrophil activation was present on the first day of hospitalization in patients who would only later require transfer to the intensive care unit, thus preceding the onset of critical illness and predicting increased mortality. In the health system database, early elevations in developing and mature neutrophil counts also predicted higher mortality rates. Altogether, we define an essential role for neutrophil activation in the pathogenesis of severe COVID-19 and identify molecular neutrophil markers that distinguish patients at risk of future clinical decompensation.

Proteomic analysis of synovial fluid from rheumatic arthritis and spondyloarthritis patients

Background

The aetiologies and pathogeneses of the joint diseases rheumatoid arthritis (RA) and spondyloarthritis (SpA) are still not fully elucidated. To increase our understanding of the molecular pathogenesis, we analysed the protein composition of synovial fluid (SF) from rheumatoid arthritis (RA) and spondyloarthritis (SpA) patients.

Methods

Fifty-six synovial fluid samples (RA, n = 32; SpA, n = 24) were digested with trypsin, and the resulting peptides were separated by liquid chromatography and analysed by tandem mass spectrometry. Additionally, the concentration of cell-free DNA (cfDNA) in the synovial fluid was measured, and plasma C-reactive protein (CRP) was determined.

Results

Three hundred thirty five proteins were identified within the SF. The more abundant proteins seen in RA SF were inflammatory proteins, including proteins originating from neutrophil granulocytes, while SpA SF had less inflammatory proteins and a higher concentration of haptoglobin. The concentration of cell-free DNA in the SF increased together with proteins that may have originated from neutrophils. Plasma CRP levels in both RA and SpA, correlated to other acute phase reactants.

Conclusions

The proteomic results underline that neutrophils are central in the RA pathology but not in SpA, and even though inhibitors of neutrophils (migration, proteinase inhibitors) were present in the SF it was not sufficient to interrupt the disease process.

Resistin family proteins in pulmonary diseases

The family of resistin-like molecules (RELMs) consists of four members in rodents (RELMα/FIZZ1/HIMF, RELMβ/FIZZ2, Resistin/FIZZ3, and RELMγ/FIZZ4) and two members in humans (Resistin and RELMβ), all of which exhibit inflammation-regulating, chemokine, and growth factor properties. The importance of these cytokines in many aspects of physiology and pathophysiology, especially in cardiothoracic diseases, is rapidly evolving in the literature. In this review article, we attempt to summarize the contribution of RELM signaling to the initiation and progression of lung diseases, such as pulmonary hypertension, asthma/allergic airway inflammation, chronic obstructive pulmonary disease, fibrosis, cancers, infection, and other acute lung injuries. The potential of RELMs to be used as biomarkers or risk predictors of these diseases also will be discussed. Better understanding of RELM signaling in the pathogenesis of pulmonary diseases may offer novel targets or approaches for the development of therapeutics to treat or prevent a variety of inflammation, tissue remodeling, and fibrosis-related disorders in respiratory, cardiovascular, and other systems.

Associations of Serum Adipokines With Subclinical Interstitial Lung Disease Among Community-Dwelling Adults: The Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

Adipokines have inflammatory and fibrotic properties that may be critical in interstitial lung disease (ILD). We examined associations of serum adipokine levels with CT imaging-based measures of subclinical ILD and lung function among community-dwelling adults.

METHODS

A subset of the original Multi-Ethnic Study of Atherosclerosis cohort (n = 1,968) had adiponectin, leptin, and resistin measured during follow-up visits (2002-2005). We used regression models to examine associations of adiponectin, leptin, and resistin levels with (1) high-attenuation areas (HAAs) from CT scans (2004-2005, n = 1,144), (2) interstitial lung abnormalities (ILAs) from CT scans (2010-2012, n = 872), and (3) FVC from spirometry (2004-2006, n = 1,446). We used -(1/HAA2), which we denoted with H, to model HAA as our outcome to meet model assumptions.

RESULTS

Higher adiponectin was associated with lower HAA on CT imaging among adults with a BMI ≥ 25 kg/m2 (P for BMI interaction = .07). Leptin was more strongly associated with ILA among never smokers compared with ever smokers (P for smoking interaction = .004). For every 1-SD increment of log-transformed leptin, the percent predicted FVC was 3.8% lower (95% CI, -5.0 to -2.5). Higher serum resistin levels were associated with greater HAA on CT in a fully adjusted model. For every 1-SD increment of log-transformed resistin there was an increase in H of 14.8 (95% CI, 3.4-26.3).

CONCLUSIONS

Higher adiponectin levels were associated with lower HAA on CT imaging among adults with a higher BMI. Higher leptin and resistin levels were associated with lower FVC and greater HAA, respectively.

Peripheral blood mononuclear cell transcriptomes reveal an over-representation of down-regulated genes associated with immunity in HIV-exposed uninfected infants

HIV-exposed uninfected (HEU) infants are disproportionately at a higher risk of morbidity and mortality, as compared to HIV-unexposed uninfected (HUU) infants. Here, we used transcriptional profiling of peripheral blood mononuclear cells to determine immunological signatures of in utero HIV exposure. We identified 262 differentially expressed genes (DEGs) in HEU compared to HUU infants. Weighted gene co-expression network analysis (WGCNA) identified six modules that had significant associations with clinical traits. Functional enrichment analysis on both DEGs and the six significantly associated modules revealed an enrichment of G-protein coupled receptors and the immune system, specifically affecting neutrophil function and antibacterial responses. Additionally, malaria pathogenicity genes (thrombospondin 1-(THBS 1), interleukin 6 (IL6), and arginine decarboxylase 2 (ADC2)) were down-regulated. Of interest, the down-regulated immunity genes were positively correlated to the expression of epigenetic factors of the histone family and high-mobility group protein B2 (HMGB2), suggesting their role in the dysregulation of the HEU transcriptional landscape. Overall, we show that genes primarily associated with neutrophil mediated immunity were repressed in the HEU infants. Our results suggest that this could be a contributing factor to the increased susceptibility to bacterial infections associated with higher morbidity and mortality commonly reported in HEU infants.

Are presepsin and resistin better markers for bacterial infection in patients with decompensated liver cirrhosis?

BACKGROUND

Bacterial infections impair prognosis in patients with cirrhosis. Presepsin and, more recently, resistin are promising markers of infection and sepsis in patients without cirrhosis.

AIMS

The aim of our study was to assess the performance of presepsin and resistin as early markers of infection compared with C reactive protein (CRP) and procalcitonin (PCT), and their prognostic relevance in patients with decompensated cirrhosis.

METHODS

One hundred and fourteen consecutive patients with decompensated cirrhosis were enrolled and followed-up for 28 days. Diagnostic performances of CRP, PCT, presepsin and resistin were assessed.

RESULTS

Fifty-three (46.5%) patients had bacterial infections of which 30 (56%) had sepsis. Presepsin and resistin had similar performance as CRP and PCT for the diagnosis of infection (best cut-off of 1444 pg/ml and 20 ng/ml, respectively) and sepsis. Presepsin (HR = 5.5; 95%CI: 2.36-13.21, p < 0.0001) and the ≥500 pg/ml increase of presepsin at 48 h (HR = 9.24; 95%CI: 3.66-23.27, p < 0.008) were independently associated with 28-day mortality.

CONCLUSIONS

Presepsin and resistin have similar diagnostic performances to CRP and PCT for bacterial infection in decompensated cirrhosis. Presepsin and Δ presepsin ≥500 pg/ml have also a prognostic relevance for 28-day mortality.

PKR suppress NLRP3-pyroptosis pathway in lipopolysaccharide-induced acute lung injury model of mice

To explore the effect of double-stranded RNA-dependent kinase (PKR) in acute lung injury (ALI) and resultant acute respiratory distress syndrome (ARDS). A mouse model of lipopolysaccharide (LPS)-induced ALI was used to evaluate the levels of phosphorylated (p)-PKR and NLRP3 in lung tissue, and the protective effects of a PKR inhibitor on lung injury. And in vitro, macrophages were incubated with LPS, with or without PKR inhibitor pre-treatment. It was observed that the levels of p-PKR protein and NLRP3 protein were significantly increased compared with those in control tissues after LPS administration. Meanwhile, treatment with PKR inhibitor decreased inflammation, injury score, wet/dry weight ratio, bronchoalveolar lavage fluid (BALF) protein levels, neutrophil count in BALF, myeloperoxidase activity and expression of high-mobility group box1(HMGB1) and interleukin(IL)-1β in the lungs of LPS-challenged mice. In vitro, we demonstrated that the levels of p-PKR and NLRP3, and cell mortality rate were increased in macrophages which were incubated with LPS compared with those without LPS administration, and PKR inhibitor significantly suppressed the level of NLRP3, caspase-1, HMGB1 and IL-1β. These results indicate that PKR plays a key role in ALI through NLRP3-pyrotosis pathway and pharmacological inhibition of PKR may have potential therapeutic effects in the treatment of patients with ALI and ARDS.

Quantitative Proteomics Reveals Differences in the Response of Neutrophils Isolated from Healthy or Diabetic Subjects to Infection with Capsule-Variant Burkholderia thailandensis

In Thailand, diabetes mellitus is the most significant risk factor for melioidosis, a severe disease caused by Burkholderia pseudomallei. In this study, neutrophils isolated from healthy or diabetic subjects were infected with B. thailandensis E555, a variant strain with a B. pseudomallei-like capsular polysaccharide used here as a surrogate micro-organism for B. pseudomallei. At 2 h post-infection, neutrophil proteins were subjected to 4-plex iTRAQ-based comparative proteomic analysis. A total of 341 proteins were identified in two or more samples, of which several proteins involved in oxidative stress and inflammation were enriched in infected diabetic neutrophils. We validated this finding by demonstrating that infected diabetic neutrophils generated significantly elevated levels of pro-inflammatory cytokines TNFα, IL-6, IL-1β, and IL-17 compared to healthy neutrophils. Our data also revealed that infected neutrophils from healthy or diabetic individuals undergo apoptotic cell death at distinctly different rates, with infected diabetic neutrophils showing a diminished ability to delay apoptosis and an increased likelihood of undergoing a lytic form of cell death, compared to infected neutrophils from healthy individuals. Increased expression of inflammatory proteins by infected neutrophils could contribute to the increased susceptibility to infection and inflammation in diabetic patients in melioidosis-endemic areas.

Simultaneous and Positively Correlated NET Formation and Autophagy in Besnoitia besnoiti Tachyzoite-Exposed Bovine Polymorphonuclear Neutrophils

Given that B. besnoiti tachyzoites infect host endothelial cells of vessels in vivo, they become potential targets for professional phagocytes [e.g., polymorphonuclear neutrophils (PMN)] when in search for adequate host cells or in case of host cell lysis. It was recently reported that B. besnoiti-tachyzoites can efficiently be trapped by neutrophil extracellular traps (NETs) released by bovine PMN. So far, the potential role of autophagy in parasite-triggered NET formation is unclear. Thus, we here analyzed autophagosome formation and activation of AMP-activated protein kinase α (AMPKα) in potentially NET-forming innate leukocytes being exposed to B. besnoiti tachyzoites. Blood was collected from healthy adult dairy cows, and bovine PMN were isolated via density gradient centrifugation. Scanning electron microscopy confirmed PMN to undergo NET formation upon contact with B. besnoiti tachyzoites. Nuclear area expansion (NAE) analysis and cell-free and anchored NETs quantification were performed in B. besnoiti-induced NET formation. Interestingly, tachyzoites of B. besnoiti additionally induced LC3B-related autophagosome formation in parallel to NET formation in bovine PMN. Notably, both rapamycin- and wortmannin-treatments failed to influence B. besnoiti-triggered NET formation and autophagosome formation. Also, isolated NETs fail to induce autophagy suggesting independence between both cellular processes. Finally, enhanced phosphorylation of AMP activated kinase α (AMPKα), a key regulator molecule of autophagy, was observed within the first minutes of interaction in tachyzoite-exposed PMN thereby emphasizing that B. besnoiti-triggered NET formation indeed occurs in parallel to autophagy.

Effect of Shenfu injection on lipopolysaccharide (LPS)-induced septic shock in rabbits

ETHNOPHARMACOLOGICAL RELEVANCE

Shenfu injection is a popular Chinese herbal formula that has been widely used in the treatment of shock in China.

AIM OF THE STUDY

To investigate the effect of Shenfu injection on lipopolysaccharide (LPS)-induced septic shock in rabbits.

MATERIALS AND METHODS

We established a septic shock model in rabbits by administering an intravenous injection of 0.6 mg/kg LPS to anesthetized rabbit, and 15 min after LPS challenge, the rabbits were intravenously administered the Shenfu injection. In these in vivo experiments, the jugular vein of the rabbits was cannulated for LPS and drug administration, and the right common carotid artery was cannulated to record the mean arterial pressure (MAP) over a 6-h period. In addition, various serum biochemical parameters, including lactate dehydrogenase (LDH), aspartate aminotransferase (AST), glutamate transaminase (ALT), creatinine (Cre), and urea nitrogen (Urea), were measured at 0, 3, and 6 h. Serum LPS levels at 6 h were determined by the test kit. And histological changes in the heart, liver and kidney tissues were observed by HE staining. Furthermore, some related small molecules in the heart tissues were detected by MALDI-TOF-MSI.

RESULTS

We found that Shenfu injection can increase the MAP, decrease the serum LPS, LDH and AST levels, and improve the tissue morphology of the heart, liver and kidney in rabbits with LPS-induced septic shock. In addition, Shenfu injection can increase the contents of ATP and taurine while reducing the content of AMP in the heart tissue during septic shock.

CONCLUSIONS

These results indicate that Shenfu injection exerts a protective effect on LPS-induced septic shock in rabbits.

Traumatic Injury and Exposure to Mitochondrial-Derived Damage Associated Molecular Patterns Suppresses Neutrophil Extracellular Trap Formation

Major traumatic injury induces significant remodeling of the circulating neutrophil pool and loss of bactericidal function. Although a well-described phenomenon, research to date has only analyzed blood samples acquired post-hospital admission, and the mechanisms that initiate compromised neutrophil function post-injury are therefore poorly understood. Here, we analyzed pre-hospital blood samples acquired from 62 adult trauma patients (mean age 44 years, range 19-95 years) within 1 h of injury (mean time to sample 39 min, range 13-59 min). We found an immediate impairment in neutrophil extracellular trap (NET) generation in response to phorbol 12-myristate 13-acetate (PMA) stimulation, which persisted into the acute post-injury phase (4-72 h). Reduced NET generation was accompanied by reduced reactive oxygen species production, impaired activation of mitogen-activated protein kinases, and a reduction in neutrophil glucose uptake and metabolism to lactate. Pre-treating neutrophils from healthy subjects with mitochondrial-derived damage-associated molecular patterns (mtDAMPs), whose circulating levels were significantly increased in our trauma patients, reduced NET generation. This mtDAMP-induced impairment in NET formation was associated with an N-formyl peptide mediated activation of AMP-activated protein kinase (AMPK), a negative regulator of aerobic glycolysis and NET formation. Indeed, activation of AMPK via treatment with the AMP-mimetic AICAR significantly reduced neutrophil lactate production in response to PMA stimulation, a phenomenon that we also observed for neutrophils pre-treated with mtDAMPs. Furthermore, the impairment in NET generation induced by mtDAMPs was partially ameliorated by pre-treating neutrophils with the AMPK inhibitor compound C. Taken together, our data demonstrate an immediate trauma-induced impairment in neutrophil anti-microbial function and identify mtDAMP release as a potential initiator of acute post-injury neutrophil dysfunction.

Myalgic encephalomyelitis or chronic fatigue syndrome: how could the illness develop?

A model of the development and progression of chronic fatigue syndrome (myalgic encephalomyelitis), the aetiology of which is currently unknown, is put forward, starting with a consideration of the post-infection role of damage-associated molecular patterns and the development of chronic inflammatory, oxidative and nitrosative stress in genetically predisposed individuals. The consequences are detailed, including the role of increased intestinal permeability and the translocation of commensal antigens into the circulation, and the development of dysautonomia, neuroinflammation, and neurocognitive and neuroimaging abnormalities. Increasing levels of such stress and the switch to immune and metabolic downregulation are detailed next in relation to the advent of hypernitrosylation, impaired mitochondrial performance, immune suppression, cellular hibernation, endotoxin tolerance and sirtuin 1 activation. The role of chronic stress and the development of endotoxin tolerance via indoleamine 2,3-dioxygenase upregulation and the characteristics of neutrophils, monocytes, macrophages and T cells, including regulatory T cells, in endotoxin tolerance are detailed next. Finally, it is shown how the immune and metabolic abnormalities of chronic fatigue syndrome can be explained by endotoxin tolerance, thus completing the model.

Intermittent Fasting in Cardiovascular Disorders-An Overview

Intermittent fasting is a form of time restricted eating (typically 16 h fasting and 8 h eating), which has gained popularity in recent years and shows promise as a possible new paradigm in the approach to weight loss and the reduction of inflammation, and has many potential long term health benefits. In this review, the authors will incorporate many aspects of fasting, mainly focusing on its effects on the cardiovascular system, involving atherosclerosis progression, benefits for diabetes mellitus type 2, lowering of blood pressure, and exploring other cardiovascular risk factors (such as lipid profile and inflammation).

Cell signaling and biological pathway in cardiovascular diseases

Currently, coronary artery disease accounts for a large proportion of deaths occurring worldwide. Damage to the heart muscle over a short period of time leads to myocardial infarction (MI). The biological mechanisms of atherosclerosis, one of the causes of MI, have been well studied. Resistin, a type of adipokine, is closely associated with intravascular level of low-density lipoprotein cholesterol and augmentation of the expression of adhesion molecules in endothelial cells. Therefore, resistin, which is highly associated with inflammation, can progress into coronary artery disease. Adenylyl cyclase associated protein 1, a binding partner of resistin, also plays an important role in inducing pro-inflammatory cytokines. The induction of these cytokines can aggravate atherosclerosis by promoting severe plaque rupture of the lesion site. Recently, drugs, such as statins that can inhibit inflammation have been extensively studied. The development of effective new drugs that can directly or indirectly block pro-inflammatory cytokines may have a great potential in the treatment of coronary artery disease in the future.