Resistin is stored in neutrophil granules being released upon challenge with inflammatory stimuli

The landscape of immune dysregulation in pediatric sepsis at a single-cell resolution

Recognizing immune dysregulation as a hallmark of sepsis pathophysiology, leukocytes have attracted major attention of investigation. While adult and pediatric sepsis are clinically distinct, their immunological delineation remains limited. Single cell technologies facilitated the characterization of immune signatures. We tackled to delineate immunological profiles of pediatric sepsis at a single-cell level by analyzing blood samples from six septic children, at both acute and recovery phases, and four healthy children. 16 single-cell transcriptomic datasets were analyzed and compared to adult sepsis dataset. We showed a unique shift in neutrophil subpopulations and functions between acute and recovery phases, along with the regulatory role of resistin. Neutrophil signatures were comparable between adult and pediatric sepsis. Innate-like CD4 T cells were predominantly and uniquely observed in acute phase of pediatric sepsis. Our study serves as a rich source of information about the phenotypic diversity and trajectory of circulating immune cells during pediatric sepsis.

A Current State of Proteomics in Adult and Pediatric Inflammatory Bowel Diseases: A Systematic Search and Review

Inflammatory bowel diseases (IBD) are systemic immune-mediated conditions with predilection for the gastrointestinal tract and include Crohn's disease and ulcerative colitis. Despite the advances in the fields of basic and applied research, the etiopathogenesis remains largely unknown. As a result, only one third of the patients achieve endoscopic remission. A substantial portion of the patients also develop severe clinical complications or neoplasia. The need for novel biomarkers that can enhance diagnostic accuracy, more precisely reflect disease activity, and predict a complicated disease course, thus, remains high. Genomic and transcriptomic studies contributed substantially to our understanding of the immunopathological pathways involved in disease initiation and progression. However, eventual genomic alterations do not necessarily translate into the final clinical picture. Proteomics may represent a missing link between the genome, transcriptome, and phenotypical presentation of the disease. Based on the analysis of a large spectrum of proteins in tissues, it seems to be a promising method for the identification of new biomarkers. This systematic search and review summarize the current state of proteomics in human IBD. It comments on the utility of proteomics in research, describes the basic proteomic techniques, and provides an up-to-date overview of available studies in both adult and pediatric IBD.

Adipokines as Diagnostic and Prognostic Markers for the Severity of COVID-19

Accumulating evidence implicates obesity as a risk factor for increased severity of disease outcomes in patients infected with severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2). Obesity is associated with adipose tissue dysfunction, which not only predisposes individuals to metabolic complications, but also substantially contributes to low-grade systemic inflammation, altered immune cell composition, and compromised immune function. This seems to impact the susceptibility and outcome of diseases caused by viruses, as obese people appear more vulnerable to developing infections and they recover later from infectious diseases than normal-weight individuals. Based on these findings, increased efforts to identify suitable diagnostic and prognostic markers in obese Coronavirus disease 2019 (COVID-19) patients to predict disease outcomes have been made. This includes the analysis of cytokines secreted from adipose tissues (adipokines), which have multiple regulatory functions in the body; for instance, modulating insulin sensitivity, blood pressure, lipid metabolism, appetite, and fertility. Most relevant in the context of viral infections, adipokines also influence the immune cell number, with consequences for overall immune cell activity and function. Hence, the analysis of the circulating levels of diverse adipokines in patients infected with SARS-CoV-2 have been considered to reveal diagnostic and prognostic COVID-19 markers. This review article summarizes the findings aimed to correlate the circulating levels of adipokines with progression and disease outcomes of COVID-19. Several studies provided insights on chemerin, adiponectin, leptin, resistin, and galectin-3 levels in SARS-CoV-2-infected patients, while limited information is yet available on the adipokines apelin and visfatin in COVID-19. Altogether, current evidence points at circulating galectin-3 and resistin levels being of diagnostic and prognostic value in COVID-19 disease.

Resistin, Elastase, and Lactoferrin as Potential Plasma Biomarkers of Pediatric Inflammatory Bowel Disease Based on Comprehensive Proteomic Screens

Inflammatory bowel disease (IBD) is an immune-mediated chronic inflammation of the intestine, which can present in the form of ulcerative colitis (UC) or as Crohn's disease (CD). Biomarkers are needed for reliable diagnosis and disease monitoring in IBD, especially in pediatric patients. Plasma samples from a pediatric IBD cohort were interrogated using an aptamer-based screen of 1322 proteins. The elevated biomarkers identified using the aptamer screen were further validated by ELISA using an independent cohort of 76 pediatric plasma samples, drawn from 30 CD, 30 UC, and 16 healthy controls. Of the 1322 proteins screened in plasma from IBD patients, 129 proteins were significantly elevated when compared with healthy controls. Of these 15 proteins had a fold change greater than 2 and 28 proteins had a fold change >1.5. Neutrophil and extracellular vesicle signatures were detected among the elevated plasma biomarkers. When seven of these proteins were validated by ELISA, resistin was the only protein that was significantly higher in both UC and CD (p < 0.01), with receiver operating characteristic area under the curve value of 0.82 and 0.77, respectively, and the only protein that exhibited high sensitivity and specificity for both CD and UC. The next most discriminatory plasma proteins were elastase and lactoferrin, particularly for UC, with receiver operating characteristic area under the curve values of 0.74 and 0.69, respectively. We have identified circulating resistin, elastase, and lactoferrin as potential plasma biomarkers of IBD in pediatric patients using two independent diagnostic platforms and two independent patient cohorts.

Immunologic, metabolic and genetic impact of diabetes on tuberculosis susceptibility

Due to the increasing prevalence of diabetes mellitus (DM) globally, the interaction between DM and major global diseases like tuberculosis (TB) is of great public health significance, with evidence of DM having about a three-fold risk for TB disease. TB defense may be impacted by diabetes-related effects on immunity, metabolism, and gene transcription. An update on the epidemiological aspects of DM and TB, and the recent trends in understanding the DM-associated immunologic, metabolic, and genetic mechanisms of susceptibility to TB will be discussed in this review. This review highlights gaps in the incomplete understanding of the mechanisms that may relate to TB susceptibility in type 2 DM (T2DM). Understanding these three main domains regarding mechanisms of TB susceptibility in T2DM patients can help us build practical treatment plans to lessen the combined burden of the diseases in rampant areas.

Neutrophil degranulation biomarkers characterize restrictive echocardiographic pattern with diastolic dysfunction in patients with diabetes

OBJECTIVE

To investigate the potential association between neutrophil degranulation and patterns of myocardial dysfunction in a cohort of patients with type 2 diabetes mellitus (T2DM).

BACKGROUND

Two distinct phenotypes of diabetic cardiomyopathy have been described: a restrictive phenotype with diastolic dysfunction (restrictive/DD) and a dilative phenotype with systolic dysfunction (dilative/SD). However, the underlying determinants of these two patterns are not yet recognized.

METHODS

In this single-centre, observational, cross-sectional study, 492 patients were recruited. Ultrasonographic measurements were performed by two experienced sonographers, blinded to the clinical data of the participants. Serum biomarkers of neutrophil degranulation were measured by enzyme-linked immunosorbent sandwich assay (ELISA).

RESULTS

After adjustment for confounders, resistin, myeloperoxidase, matrix metalloproteinase 8 and matrix metalloproteinase 9/tissue inhibitor of metalloproteinases 1 complex were positively associated with the restrictive/DD pattern compared with the normal pattern. Similarly, MPO was positively associated with the dilative/SD pattern compared with the normal pattern, and resistin was negatively associated with the dilative/SD pattern compared with the restrictive/DD pattern.

CONCLUSIONS

Neutrophil degranulation is associated with the restrictive/DD echocardiographic pattern in patients with T2DM, but not with the normal pattern and dilative/SD patterns. Neutrophils could have a pivotal role in the pathogenesis of myocardial dysfunction, and particularly diastolic dysfunction, in patients with T2DM.

Halting Tumor Progression via Novel Non-Hydroxamate Triazole-Based Mannich Bases MMP-2/9 Inhibitors; Design, Microwave-Assisted Synthesis, and Biological Evaluation

Matrix metalloproteinases (MMPs) are key signaling modulators in the tumor microenvironment. Among MMPs, MMP-2 and MMP-9 are receiving renewed interest as validated druggable targets for halting different tumor progression events. Over the last decades, a diverse range of MMP-2/9 inhibitors has been identified starting from the early hydroxamic acid-based peptidomimetics to the next generation non-hydroxamates. Herein, focused 1,2,4-triazole-1,2,3-triazole molecular hybrids with varying lengths and decorations, mimicking the thematic features of non-hydroxamate inhibitors, were designed and synthesized using efficient protocols and were alkylated with pharmacophoric amines to develop new Mannich bases. After full spectroscopic characterization the newly synthesized triazoles tethering Mannich bases were subjected to safety assessment via MTT assay against normal human fibroblasts, then evaluated for their potential anticancer activities against colon (Caco-2) and breast (MDA-MB 231) cancers. The relatively lengthy bis-Mannich bases 15 and 16 were safer and more potent than 5-fluorouracil with sub-micromolar IC₅₀ and promising selectivity to the screened cancer cell lines rather than normal cells. Both compounds upregulated p53 (2–5.6-fold) and suppressed cyclin D expression (0.8–0.2-fold) in the studied cancers, and thus, induced apoptosis. 15 was superior to 16 in terms of cytotoxic activities, p53 induction, and cyclin D suppression. Mechanistically, both were efficient MMP-2/9 inhibitors with comparable potencies to the reference prototype hydroxamate-based MMP inhibitor NNGH at their anticancer IC₅₀ concentrations. 15 (IC₅₀ = 0.143 µM) was 4-fold more potent than NNGH against MMP-9 with promising selectivity (3.27-fold) over MMP-2, whereas 16 was comparable to NNGH. Concerning MMP-2, 16 (IC₅₀ = 0.376 µM) was 1.2-fold more active than 15. Docking simulations predicted their possible binding modes and highlighted the possible structural determinants of MMP-2/9 inhibitory activities. Computational prediction of their physicochemical properties, ADMET, and drug-likeness metrics revealed acceptable drug-like criteria.

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.

Neutrophils: Need for Standardized Nomenclature

Neutrophils are the most abundant innate immune cell with critical anti-microbial functions. Since the discovery of granulocytes at the end of the nineteenth century, the cells have been given many names including phagocytes, polymorphonuclear neutrophils (PMN), granulocytic myeloid derived suppressor cells (G-MDSC), low density neutrophils (LDN) and tumor associated neutrophils (TANS). This lack of standardized nomenclature for neutrophils suggest that biologically distinct populations of neutrophils exist, particularly in disease, when in fact these may simply be a manifestation of the plasticity of the neutrophil as opposed to unique populations. In this review, we profile the surface markers and granule expression of each stage of granulopoiesis to offer insight into how each stage of maturity may be identified. We also highlight the remarkable surface marker expression profiles between the supposed neutrophil populations.

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.

The regulation of serum resistin levels in metabolically healthy and unhealthy obese individuals

PURPOSE

We have recently demonstrated that absolute counts of circulating proinflammatory monocytes were lower in obese patients without metabolic syndrome (MS) (metabolically healthy obese, MHO) compared with those with MS (metabolically unhealthy obese, MUO), but higher compared with healthy lean controls (MHL). We hypothesized that circulating resistin, a cytokine secreted by white blood cells (WBC), is involved in obesity-related low-grade inflammation. The aim of this study was to (a) determine serum resistin levels among MUO and MHO subjects and (b) investigate the role of circulating WBC subsets as potential determinants of resistin.

METHODS

Study participants were 58 obese (33 MUO, 25 MHO) and 25 MHL individuals. Serum levels of resistin, high-sensitivity C-reactive protein (hsCRP), and absolute counts of circulating WBC subpopulations were determined. Comparisons were sex- and age-adjusted.

RESULTS

Serum resistin levels in MHL were lower compared with those of obese (p = 0.041), but similar to those of MHO (p = 0.856) individuals. Both resistin (p = 0.005) and absolute neutrophil count (NeuA) (p = 0.025) were higher in MUO compared with MHO. The difference in resistin levels between obese and MHL individuals disappeared after adjustment for NeuA. Resistin correlated positively with absolute total monocyte count (p = 0.037) in MHL and with body mass index (BMI) (p = 0.023), hsCRP (p = 0.022), and NeuA (p = 0.044) in obese subjects. Resistin association with ΒΜΙ disappeared after adjustment for hsCRP, while association with hsCRP disappeared after further adjustment for NeuA.

CONCLUSION

Circulating resistin was higher in MUO compared with MHO. The increased secretion of resistin by the greater number of neutrophils in the former may have contributed to this regulation.

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.

Immune Dysfunction in Uremia 2020

Cardiovascular disease and infections are major causes for the high incidence of morbidity and mortality of patients with chronic kidney disease. Both complications are directly or indirectly associated with disturbed functions or altered apoptotic rates of polymorphonuclear leukocytes, monocytes, lymphocytes, and dendritic cells. Normal responses of immune cells can be reduced, leading to infectious diseases or pre-activated/primed, giving rise to inflammation and subsequently to cardiovascular disease. This review summarizes the impact of kidney dysfunction on the immune system. Renal failure results in disturbed renal metabolic activities with reduced renin, erythropoietin, and vitamin D production, which adversely affects the immune system. Decreased kidney function also leads to reduced glomerular filtration and the retention of uremic toxins. A large number of uremic toxins with detrimental effects on immune cells have been identified. Besides small water-soluble and protein-bound compounds originating from the intestinal microbiome, several molecules in the middle molecular range, e.g., immunoglobulin light chains, retinol-binding protein, the neuropeptides Met-enkephalin and neuropeptide Y, endothelin-1, and the adipokines leptin and resistin, adversely affect immune cells. Posttranslational modifications such as carbamoylation, advanced glycation products, and oxidative modifications contribute to uremic toxicity. Furthermore, high-density lipoprotein from uremic patients has an altered protein profile and thereby loses its anti-inflammatory properties.

Protective role of lycopene against metabolic disorders induced by chronic bisphenol A exposure in rats

This study was conducted to elucidate the ameliorative potential of lycopene (LYC) against the metabolic toxicity induced by bisphenol A (BPA) in rats. Male rats (n = 28) were divided into 4 equal groups: control group, LYC group was given lycopene (10 mg/kg BW), BPA group was given 10 mg/kg BW of BPA, and the last group was administered BPA and LYC at 10 mg/kg via gavage for 90 consecutive days. Body weight (BW) gain, lipid profile, and total antioxidant capacity (TAC) were assessed. Oral glucose tolerance test (OGTT), homeostasis model assessment-estimated insulin resistance (HOMA-IR), thyroid hormones, interleukin-1 beta (IL-1β), leptin, and resistin were assayed. Moreover, immunohistochemistry of TNF-α was performed in adipose tissue. BPA-treated rats showed significant reduction in BW gain and deteriorations in lipid profile, TAC, OGTT, and thyroid hormones as well as significant increases in HOMA-IR, IL-1β, leptin, and resistin. While, improvement of metabolic parameters was observed when LYC was administrated with BPA. Intense TNF-α immunostaining was detected in the fat of BPA-treated rats but the intensity decreased when LYC was administrated with BPA. In conclusion, LYC ameliorated the adverse effects of BPA on metabolism through its antioxidant potential and its reduction of TNF-α expression in adipose tissue.

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.

Relationship Between Resistin Levels and Sepsis Among Children Under 12 Years of Age: A Case Control Study

Objective: The aim of this study was to investigate the level of resistin in children with and without sepsis hospitalized in the pediatric intensive care unit (PICU) and compare them to levels in healthy subjects in order to determine the trend of resistin levels in children in PICUs and also to identify the cut-off values for positive sepsis. Methods: This was a case-control study conducted in 2014 at a children's hospital in Tabriz, Iran. Three groups were investigated, a case group comprised of patients with sepsis admitted to PICU and two control groups; one made up of patients admitted to PICU without sepsis and the other of healthy children. Variables included demographic, anthropometric (growth metric percentile), and clinical factors. Results: Patients were randomized into control group A (n = 12, 48%), control group B (n = 11, 44%), and the sepsis group (n = 24, 47.1%). The difference in the means of resistin levels was significant on the first, fourth, and seventh days (P < 0.0001) in the case and control group A. Means comparisons in the case and control group B revealed significant differences on the fourth and seventh day (P = 0.005 and P < 0.0001, respectively) but not on the first day (P = 0.246). The trend of resistin levels increased in the septic group (F Huynh-Feldt = 37.83, P < 0.0001). The diagnostic accuracy of resistin level was high for discriminating sepsis (area under the receiver operating characteristic curve [AUC] 0.864 [SE = 0.41]). The sensitivity was 0.824 and specificity 0.72 with a cut-off point of 5.2 ng/ml on the first day. Conclusion: In the present study, resistin level can be used as an indicator of sepsis in children admitted to PICU. However, the cut-off point based upon when a prediction could be made is different and is dependent on a variety of factors, such as control group and number of days since the first signs of sepsis.

Single-Cell Transcriptome Analysis of CD34+ Stem Cell-Derived Myeloid Cells Infected With Human Cytomegalovirus

Myeloid cells are important sites of lytic and latent infection by human cytomegalovirus (CMV). We previously showed that only a small subset of myeloid cells differentiated from CD34⁺ hematopoietic stem cells is permissive to CMV replication, underscoring the heterogeneous nature of these populations. The exact identity of resistant and permissive cell types, and the cellular features characterizing the latter, however, could not be dissected using averaging transcriptional analysis tools such as microarrays and, hence, remained enigmatic. Here, we profile the transcriptomes of ∼7000 individual cells at day 1 post-infection using the 10× genomics platform. We show that viral transcripts are detectable in the majority of the cells, suggesting that virion entry is unlikely to be the main target of cellular restriction mechanisms. We further show that viral replication occurs in a small but specific sub-group of cells transcriptionally related to, and likely derived from, a cluster of cells expressing markers of Colony Forming Unit – Granulocyte, Erythrocyte, Monocyte, Megakaryocyte (CFU-GEMM) oligopotent progenitors. Compared to the remainder of the population, CFU-GEMM cells are enriched in transcripts with functions in mitochondrial energy production, cell proliferation, RNA processing and protein synthesis, and express similar or higher levels of interferon-related genes. While expression levels of the former are maintained in infected cells, the latter are strongly down-regulated. We thus propose that the preferential infection of CFU-GEMM cells may be due to the presence of a pre-established pro-viral environment, requiring minimal optimization efforts from viral effectors, rather than to the absence of specific restriction factors. Together, these findings identify a potentially new population of myeloid cells permissive to CMV replication, and provide a possible rationale for their preferential infection.

Oxidative stress and adipokine levels were significantly correlated in diabetic patients with hyperglycemic crises

BACKGROUND

To investigate the relationship between blood adipokine level and oxidative stress in diabetic patients with hyperglycemic crises before and after treatment.

METHODS

We measured superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, total antioxidant capacity (TAC), and levels of 8-iso-prostaglandin F2α (8-iso-PGF2α), adiponectin, leptin, and resistin in 63 diabetic patients with hyperglycemic crises.

RESULTS

Prior to treatment, patients with hyperglycemic crises had significantly lower serum SOD activity, TAC, and adiponectin and leptin levels, and higher serum levels of MDA, 8-iso-PGF2α, and resistin compared with the healthy control individuals (all at P < 0.05). After treatment, SOD, TAC, adiponectin, and leptin levels increased significantly, while MDA, 8-iso-PGF2α, and resistin levels decreased significantly (all at P < 0.05) in the patients.

CONCLUSIONS

Diabetic patients with hyperglycemic crises have increased oxidative stress, which is associated with serum adipokine abnormalities; improved oxidative stress after treatment suggests that oxidative stress may serve as target and/or indicator for the treatment of hyperglycemic crises.

Sensitive and high throughput quantification of abscisic acid based on quantitative real time immuno-PCR

BACKGROUND

Abscisic acid (ABA) functions as a stress phytohormone in many growth and developmental processes in plants. The ultra-sensitive determination of ABA would help to better understand its vital roles and action mechanisms.

RESULTS

We report a new sensitive and high throughput quantitative real time immuno-PCR (qIPCR) method based on biotin-avidin linkage system for ABA determination in plants. ABA monoclonal antibody (McAb) coated on the inner surface of PCR well pretreated with glutaraldehyde. The pre-prepared probe complex, including biotinylated McAb, biotinylated DNA and streptavidin linker, was convenient for high throughput operations. Finally, probe DNA was quantified by real-time PCR. The detectable ranges were from 10 to 40 ng/L with a limit of detection (LOD) of 2.5 fg. ABA contents in plant sample were simultaneously analyzed using LC-MS/MS to validate the qIPCR method. The results showed that qIPCR method has good specificity and repeatability with a recovery rate of 96.9%.

CONCLUSION

The qIPCR method is highly sensitive for ABA quantification for actual plant samples with an advantage of using crude extracts instead of intensively purified samples.

Ascitic fluid regulates the local innate immune response of patients with cirrhosis

Ascitic neutrophils from cirrhotic patients with spontaneous bacterial peritonitis (SBP) exhibit an impaired oxidative burst that could facilitate bacterial infection. However, the influence of the cell-free ascitic fluid of these patients on neutrophil function has not been investigated. To analyze this influence, we determined the ascitic levels of cytokines, resistin, and lactoferrin and their association with neutrophil function, disease severity score, and SBP resolution. We analyzed NETosis induction by microscopy and oxidative burst by the flow cytometry of healthy neutrophils cultured in ascitic fluid from cirrhotic patients with sterile ascites (SA) and with SBP before and after antibiotic treatment. Resistin, IL-6, IL-1 receptor antagonist, IL-1β, and lactoferrin levels were measured in ascitic fluids and supernatants of cultured neutrophils and PBMCs by ELISA. Upon stimulation, healthy neutrophils cultured in SBP ascitic fluid produced lower NETosis and oxidative burst than those cultured in SA. Ascitic resistin levels were negatively correlated with NETosis, oxidative burst, and ascitic glucose levels; and positively correlated with the model for end-stage liver disease score. After an E. coli or TNF-α stimulus, neutrophils were the major resistin producers. Resistin indirectly reduced the oxidative burst of neutrophils and directly reduced the inflammatory phenotype of monocytes and TNF-α production. Bacterial-induced resistin production can down-regulate the inflammatory response of macrophages and neutrophil function in ascitic fluid. Consequently, this down-regulation may jeopardize the elimination of bacteria that translocate to ascitic fluid in patients with cirrhosis.

Down-regulated resistin level in consequence of decreased neutrophil counts in untreated Grave's disease

Resistin, belongs to cysteine-rich secretory protein, is mainly produced by circulating leukocytes, such as neutrophils monocytes and macrophages in humans. To date, few but controversial studies have reported about resistin concentrations in hyperthyroid patients, especially in Graves' disease (GD). We undertaked a controlled, prospective study to explore the serum resistin concentration in GD patients before and after -MMI treatment. In addition, we also investigated the main influencing factor on serum resistin level and discuessed the potential role of serum resistin plays in GD patients. 39 untreated GD (uGD) patients, including 8 males and 31 females, were enrolled in our investigation. All of these patients were prescribed with MMI treatment, in addition to 25 healthy controls. Anthropometric parameters and hormone assessment were measured. Enzyme-linked immunosorbent assay was used to detect serum resistin concentration in different stages of GD patients. Furthermore, neutrophil cell line NB4 with or without T3 treatment to detect the effect of thyroid hormones on resistin expression. The serum resistin level and neutrophil counts in untreated GD patients were significantly declined. And all of these parameters were recovered to normal after MMI treatment in ethyroid GD (eGD) and TRAb-negative conversion (nGD) patients. Resistin concentration exhibited a negative correlation with FT3 and FT4, but a positive correlation with absolute number of neutrophiles in uGD patients, whereas did not correlate with thyroid autoimmune antibodies and BMI. Neutrophile cell line, NB4, produced decreased expression of resistin when stimulated with T3. Our study showed a decrease of serum resistin level in GD patients and we suggested that the serum resistin might primarily secreted from circulating neutrophils and down-regulated by excessive thyroid hormones in GD patients.

The Ontogeny of a Neutrophil: Mechanisms of Granulopoiesis and Homeostasis

Comprising the majority of leukocytes in humans, neutrophils are the first immune cells to respond to inflammatory or infectious etiologies and are crucial participants in the proper functioning of both innate and adaptive immune responses. From their initial appearance in the liver, thymus, and spleen at around the eighth week of human gestation to their generation in large numbers in the bone marrow at the end of term gestation, the differentiation of the pluripotent hematopoietic stem cell into a mature, segmented neutrophil is a highly controlled process where the transcriptional regulators C/EBP-α and C/EBP-ε play a vital role. Recent advances in neutrophil biology have clarified the life cycle of these cells and revealed striking differences between neonatal and adult neutrophils based on fetal maturation and environmental factors. Here we detail neutrophil ontogeny, granulopoiesis, and neutrophil homeostasis and highlight important differences between neonatal and adult neutrophil populations.

Hemoadsorption corrects hyperresistinemia and restores anti-bacterial neutrophil function

Background

Mounting evidence suggests that sepsis-induced morbidity and mortality are due to both immune activation and immunosuppression. Resistin is an inflammatory cytokine and uremic toxin. Septic hyperresistinemia (plasma resistin >20 ng/ml) has been associated with greater disease severity and worse outcomes, and it is further exacerbated by concomitant acute kidney injury (AKI). Septic hyperresistinemia disturbs actin polymerization in neutrophils leading to impaired neutrophil migration, a crucial first-line mechanism in host defense to bacterial infection. Our experimental objective was to study the effects of hyperresistinemia on other F-actin-dependent neutrophil defense mechanisms, in particular intracellular bacterial clearance and generation of reactive oxygen species (ROS). We also sought to examine the effects of hemoadsorption on hyperresistinemia and neutrophil dysfunction.

Methods

Thirteen patients with septic shock and six control patients were analyzed for serum resistin levels and their effects on neutrophil migration. In vitro, following incubation with resistin-spiked serum samples, Pseudomonasaeruginosa clearance and ROS generation in neutrophils were measured. Phosphorylation of 3-phosphoinositide-dependent protein kinase-1 (PDPK1) was assessed using flow cytometry. In vitro hemoadsorption with both Amberchrome™ columns (AC) and CytoSorb® cartridges (CC) were used to test correction of hyperresistinemia. We further tested AC for their effect on cell migration and ROS generation and CC for their effect on bacterial clearance.

Results

Patients with septic shock had higher serum resistin levels than control ICU patients and showed a strong, negative correlation between hyperresistinemia and neutrophil transwell migration (ρ= − 0.915, p < 0.001). In vitro, neutrophils exposed to hyperresistinemia exhibited twofold lower intracellular bacterial clearance rates compared to controls. Resistin impaired intracellular signaling and ROS production in a dose-dependent manner. Hemoadsorption with AC reduced serum concentrations of resistin and restored neutrophil migration and generation of ROS to normal levels. Hemoadsorption with CC also corrected hyperresistinemia and reconstituted normal intracellular bacterial clearance.

Conclusions

Septic hyperresistinemia strongly correlates with inhibition of neutrophil migration in vitro. Hyperresistinemia itself reversibly impairs neutrophil intracellular bacterial clearance and ROS generation. Hemoadsorption therapy with a clinically approved device corrects hyperresistinemia and neutrophil dysfunction. It may therefore provide a therapeutic option to improve neutrophil function during septic hyperresistinemia and ultimately alleviate immunosuppression in this disease state.

IGF-1R signalling contributes to IL-6 production and T cell dependent inflammation in rheumatoid arthritis

BACKGROUND

Signalling through insulin-like growth factor 1 receptor (IGF-1R) is essential for cell survival, but may turn pathogenic in uncontrolled tissue growth in tumours. In rheumatoid arthritis (RA), the IGF-1R signalling is activated and supports expansion of the inflamed synovia.

AIM

In the present study, we assess if disruption of IGF-1R signalling resolves arthritis.

MATERIAL AND METHODS

Clinical associations of IGF-1R expression in leukocytes of the peripheral blood were studied in 84 RA patients. Consequences of the IGF-1R signalling inhibition for arthritis were studied in mBSA immunised Balb/c mice treated with NT157 compound promoting degradation of insulin receptor substrates.

RESULTS

In RA patients, high expression of IGF-1R in leukocytes was associated with systemic inflammation as verified by higher expression of NF-kB, serum levels of IL6 and erythrocyte sedimentation rate, and higher pain perception. Additionally, phosphorylated IGF-1R and STAT3 enriched T cells infiltrate in RA synovia. Treatment with NT157 inhibited the phosphorylation of IGF-1R and STAT3 in synovia, and alleviated arthritis and joint damage in mice. It also reduced expression of IGF-1R and despaired ERK and Akt signalling in spleen T cells. This limited IL-6 production, changed RoRgt/FoxP3 balance and IL17 levels.

CONCLUSION

IGF-1R signalling contributes to T cell dependent inflammation in arthritis. Inhibition of IGF-1R on the level of insulin receptor substrates alleviates arthritis by restricting IL6-dependent formation of Th17 cells and may open for new treatment strategies in RA.

Reversal of Acute Kidney Injury-Induced Neutrophil Dysfunction: A Critical Role for Resistin

OBJECTIVES

To assess the reversibility of acute kidney injury-induced neutrophil dysfunction and to identify involved mechanisms.

DESIGN

Controlled laboratory experiment and prospective observational clinical study.

SETTING

University laboratory and hospital.

SUBJECTS

C57BL/6 wild-type mice.

PATIENTS

Patients with septic shock with or without acute kidney injury.

INTERVENTIONS

Murine acute kidney injury was induced by intraperitoneal injections of folic acid (nephrotoxic acute kidney injury) or by IM injections of glycerol (rhabdomyolysis-induced acute kidney injury). After 24 hours, we incubated isolated neutrophils for 3 hours in normal mouse serum or minimum essential medium buffer. We further studied the effects of plasma samples from 13 patients with septic shock (with or without severe acute kidney injury) on neutrophilic-differentiated NB4 cells.

MEASUREMENTS AND MAIN RESULTS

Experimental acute kidney injury significantly inhibited neutrophil migration and intracellular actin polymerization. Plasma levels of resistin, a proinflammatory cytokine and uremic toxin, were significantly elevated during both forms of acute kidney injury. Incubation in serum or minimum essential medium buffer restored normal neutrophil function. Resistin by itself was able to induce acute kidney injury-like neutrophil dysfunction in vitro. Plasma resistin was significantly higher in patients with septic shock with acute kidney injury compared with patients with septic shock alone. Compared with plasma from patients with septic shock, plasma from patients with septic shock and acute kidney injury inhibited neutrophilic-differentiated NB4 cell migration. Even after 4 days of renal replacement therapy, plasma from patients with septic shock plus acute kidney injury still showed elevated resistin levels and inhibited neutrophilic-differentiated NB4 cell migration. Resistin inhibited neutrophilic-differentiated NB4 cell migration and intracellular actin polymerization at concentrations seen during acute kidney injury, but not at normal physiologic concentrations.

CONCLUSIONS

Acute kidney injury-induced neutrophil dysfunction is reversible in vitro. However, standard renal replacement therapy does not correct this defect in patients with septic shock and acute kidney injury. Resistin is greatly elevated during acute kidney injury, even with ongoing renal replacement therapy, and is sufficient to cause acute kidney injury-like neutrophil dysfunction by itself.

Alterations in neonatal neutrophil function attributable to increased immature forms

At birth neonatal neutrophil composition differs from that of adults due to a higher number of circulating immature forms. To date only a single study has evaluated neutrophil performance based on cell maturity. For this study, we examined functional differences in chemotaxis and phagocytosis between neonatal and adult neutrophils based on cell development and labor exposure.

METHODS

Neutrophils were obtained by venipuncture from adults and cord blood from healthy term neonates delivered vaginally or by cesarean section. Transwells and the chemoattractant fMLP were used to evaluate chemotaxis. Phagocytosis assays were performed using GFP-labeled E.coli (RS218) and whole blood. Neutrophil maturation was measured by an accurate and verified flow cytometry technique using the markers CD45, CD11b, and CD16. QuantiGene Plex and Procarta immunoassays were used to determine cytokine and chemokine gene expression and protein concentration, respectively.

RESULTS

Labor exposure did not alter neonatal neutrophil function in this study. Neonatal and adult mature neutrophils performed chemotaxis and phagocytosis equally well, while immature forms showed marked impairments. Neonatal immature granulocytes, though, completed chemotaxis more proficiently than those of adults. Although cytokine and chemokine levels varied between neonatal and adult groups, no differences were detected in neonates based upon labor exposure.

CONCLUSION

Historically documented functional impairments of neonatal neutrophils may be due to the increased number of developmentally immature forms at birth rather than absolute global deficiencies.

Regulation and function of AMPK in physiology and diseases

5′-adenosine monophosphate (AMP)-activated protein kinase (AMPK) is an evolutionarily conserved serine/threonine kinase that was originally identified as the key player in maintaining cellular energy homeostasis. Intensive research over the last decade has identified diverse molecular mechanisms and physiological conditions that regulate the AMPK activity. AMPK regulates diverse metabolic and physiological processes and is dysregulated in major chronic diseases, such as obesity, inflammation, diabetes and cancer. On the basis of its critical roles in physiology and pathology, AMPK is emerging as one of the most promising targets for both the prevention and treatment of these diseases. In this review, we discuss the current understanding of the molecular and physiological regulation of AMPK and its metabolic and physiological functions. In addition, we discuss the mechanisms underlying the versatile roles of AMPK in diabetes and cancer.

Changes in profile of lipids and adipokines in patients with newly diagnosed hypothyroidism and hyperthyroidism

Changes in profile of lipids and adipokines have been reported in patients with thyroid dysfunction. But the evidence is controversial. The present study aimed to explore the relationships between thyroid function and the profile of lipids and adipokines. A cross-sectional study was conducted in 197 newly diagnosed hypothyroid patients, 230 newly diagnosed hyperthyroid patients and 355 control subjects. Hypothyroid patients presented with significantly higher serum levels of total cholesterol, triglycerides, low-density lipoprotein cholesterol (LDLC), fasting insulin, resistin and leptin than control (p < 0.05). Hyperthyroid patients presented with significantly lower serum levels of high-density lipoprotein cholesterol, LDLC and leptin, as well as higher levels of fasting insulin, resistin, adiponectin and homeostasis model insulin resistance index (HOMA-IR) than control (p < 0.05). Nonlinear regression and multivariable linear regression models all showed significant associations of resistin or adiponectin with free thyroxine and association of leptin with thyroid-stimulating hormone (p < 0.001). Furthermore, significant correlation between resistin and HOMA-IR was observed in the patients (p < 0.001). Thus, thyroid dysfunction affects the profile of lipids and adipokines. Resistin may serve as a link between thyroid dysfunction and insulin resistance.

Correlation between Resistin, Tuberculosis and Khat Addiction: A Study from South Western Province of Saudi Arabia

Tuberculosis(TB) is a disease of global significance, which accounts for a death in every 15 seconds. Recent studies shows TB is rising in certain parts of the world, and Saudi Arabia is one of them. Several factor contribute in predisposing the subjects for infection including but not limited to addiction to various compounds which have immune modulation properties, such as amphetamines and Heroin etc. Khat a plant whose leaves are chewed for its euphoric effect in east Africa and Arabian Peninsula including Saudi Arabia, is considered as mildly addictive, and its principle compound, Cathinone shares structural and functional similarity with amphetamine a known immunomodulator. Tuberculosis being a disease of immune modulation has a varied spectrum of complex interplay of proinflammatory molecules, resistin is one of them. In the present study, we try to explore the trinity of khat addiction, serum resistin level and tuberculosis by correlating the serum resistin level in non khat addicted healthy subjects, khat addicted healthy subjects, and in patients, both khat addicted and non khat addicted, with active tuberculosis. We observed significantly higher resistin level among the apparently healthy khat addicted subjects as compared to non addicted healthy controls. Thereafter, when we compare the resistin levels between khat addicted and non khat addicted TB patients we did not found significant difference between the two groups. However bacillary load was observe to be significantly higher among the khat addicted TB patient as compare to non addicted one. Validation of above results in animal model revealed dose dependant increase in bacillary growth in the Wistar rats treated with khat. Taken together these results suggest the role of khat in immune modulation albeit in the limited frame of resistin level.

Circulating resistin levels are early and significantly increased in deceased brain dead organ donors, correlate with inflammatory cytokine response and remain unaffected by steroid treatment

Introduction

Resistin is a pro-inflammatory adipokine that increases after brain injury (trauma, bleeding) and may initiate an inflammatory response. Resistin was found increased in deceased, brain dead organ donors (DBD) and correlated with delayed graft function after kidney transplantation. The kinetics of resistin during brain death (BD), its impact on the inflammatory response and the influence of several donor variables on resistin levels are still unknown.

Methods

Resistin along with a panel of Th1/Th2 cytokines [interferon (IFN)-gamma, interleukin (IL)-1beta, IL-2, IL-6, IL-8, IL10, IL-12, IL-13 and tumor necrosis factor (TNF)] was analyzed in 36 DBDs after the diagnosis of BD and before organ procurement and in 12 living kidney donors (LD). The cytokine levels and resistin were analyzed in relation to donor parameters including cause of death, donors’ age and steroid treatment.

Results

Resistin levels were higher in DBDs both at BD diagnosis and before organ procurement compared to LD (p < 0.001). DBDs had significantly increased IL-1beta, IL-6, IL-8, IL-10 and TNF levels at both time points compared with LD. In DBDs, resistin at BD diagnosis correlated positively with IL-1beta (r_s 0.468, p = 0.007), IL-6 (r_s 0.511, p = 0.002), IL-10 (r_s 0.372, p = 0.028), IL-12 (r_s 0.398, p = 0.024), IL-13 (r_s 0.397, p = 0.030) and TNF (r_s 0.427, p = 0.011) at procurement. The cause of death, age over 60 and steroid treatment during BD did not affect resistin levels. However, steroid treatment significantly decreased pro-inflammatory cytokines IL-1beta, IL-8, TNF and IFN-gamma at the time of organ procurement.

Conclusions

Resistin is increased early in DBDs, remains increased throughout the period of BD and correlates strongly with pro-inflammatory mediators. Resistin level, in contrast to cytokines, is not affected by steroid treatment. Resistin increase is related to the BD but is not influenced by age or cause of death. Resistin may be one of the initial triggers for the systemic inflammatory activation seen in DBDs.

Gene expression analysis of children with acute hematogenous osteomyelitis caused by Methicillin-resistant Staphylococcus aureus: correlation with clinical severity of illness

Children with acute hematogenous osteomyelitis (AHO) demonstrate a broad spectrum of clinical manifestations, ranging from mild to severe. Several advances have been achieved in the study of host immune response to acute invasive Staphylococcus aureus infections through gene expression analysis. However, previous research has neither attempted to evaluate the response of children with AHO specific to Methicillin-resistant Staphylococcus aureus (MRSA) nor to correlate gene expression with clinical phenotype. Study objective was to correlate gene expression of children with AHO due to MRSA with clinical severity of illness. Whole blood samples were obtained in Tempus tubes from 12 children with osteomyelitis once cultures obtained directly from the site of infection confirmed to be positive for MRSA. Using an Illumina platform and a systems-wide modular analysis, microarray findings from ten of these children were compared to that of nine healthy (age, ethnicity and gender) matched controls and correlated with clinical severity of illness. Children with AHO from MRSA demonstrated over-expression of innate immunity with respect to neutrophil activity, coagulation, inflammatory response, and erythrocyte development. Concurrently, these children demonstrated under-expression of adaptive immunity with respect to lymphocyte activation and activity of T-cell, cytotoxic or NK cell, and B-cell lines. Three over-expressed genes, P2RX1, SORT1, and RETN, and two under-expressed genes, LOC641788 and STAT 4, were significantly correlated with severity of illness. STAT 4 showed the strongest correlation (R2 = –0.83). STAT4 downregulation could potentially explain under-expression of genes related to adaptive immunity in this cohort of patients with AHO. This study identified specific genes which correspond to disease severity during the early hospitalization of children with AHO from MRSA. Pattern recognition of this combination of genes could help to identify in the future severe clinical phenotypes before the disease is fully manifest and direct appropriate attention and resources to those children.

Serum resistin levels are associated with adiposity and insulin sensitivity in obese Hispanic subjects

BACKGROUND AND AIMS

Resistin is involved in the development of obesity and insulin resistance (IR) in mice and may play a similar role in humans through mechanisms that remain unresolved. The objective of this study was to characterize the relationship between resistin levels in obese subjects with and without IR among Hispanic subjects.

MATERIAL AND METHODS

A cross-sectional study was performed on 117 nondiabetic Hispanic subjects of both genders that were allocated into three study groups: A control group (n=47) of otherwise healthy individuals in metabolic balance, a group with obesity (OB) (n=36), and a group with obesity and IR (OB-IR) (n=34). Anthropometric and clinical characterization was carried out, and resistin levels were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

We found that resistin levels were higher in OB and OB-IR groups when compared to the control group (1331.79±142.15 pg/mL, 1266.28±165.97 pg/mL vs. 959.21±171.43 pg/mL; P<0.05), an effect that was not confounded by age (control, 34.04±10.00 years; OB, 37.30±10.78 years; and OB-IR, 35.67±10.15 years). In addition, we observed a significant correlation (P<0.001) between resistin levels and higher adiposity and insulin sensitivity (IS) in our cohort.

CONCLUSIONS

Our results suggest that higher resistin levels are associated with higher adiposity and lower IS among obese Hispanic subjects.

The role of resistin in inflammatory myopathies

Both immune and non-immune mechanisms are involved in muscle damage and dysfunction occurring in idiopathic inflammatory myopathies (IIMs). Crosstalk among inflammatory cells, muscle and endothelial cells is essential in the pathogenesis of IIMs. Resistin, originally described as an adipokine linking obesity and insulin resistance in rodents, has been shown a pro-inflammatory molecule in humans. Besides its direct effect on production of several inflammatory mediators, resistin influences chemotaxis, migration, proliferation, cell survival, endothelial dysfunction and metabolism--all aspects implicated in the pathogenesis of IIMs. Up-regulation of resistin in muscle tissue and elevated serum resistin levels have been recently demonstrated in patients with IIMs. In addition, serum levels of resistin reflected global disease activity, including extramuscular organ involvement, in patients with this disease. However, there are currently not sufficient data to distinguish the features of resistin that cause injury of muscle tissue from those that promote muscle regeneration and repair. The aim of this review is therefore to summarize current knowledge about potential implication of resistin in idiopathic inflammatory myopathies.

Porphyromonas gingivalis and Escherichia coli lipopolysaccharide causes resistin release from neutrophils

OBJECTIVES

It was reported that periodontitis is associated with increased serum resistin levels. We examined whether there was a difference between the release of resistin from neutrophils incubated lipopolysaccharide (LPS) from Porphyromonas gingivalis and with LPS from Escherichia coli, and which cell-surface receptors and intracellular kinases were involved in this process.

METHODS

Several concentrations of P. gingivalis-LPS and E. coli-LPS were added to neutrophils, supernatant from cultured neutrophils was collected, and resistin levels were measured by ELISA. To examine signaling pathways, neutrophils were pretreated with monoclonal antibodies against CD14, CD18, TLR2, and TLR4, and specific inhibitors of PI3K and MAPKs.

RESULTS

Resistin release from neutrophils was induced both by P. gingivalis-LPS and E. coli-LPS, but resistin release by P. gingivalis-LPS was weaker than E. coli-LPS in low concentrations. Resistin release was decreased by pretreatment with monoclonal antibodies against CD14, CD18, and TLR4, but not by TLR2. Moreover, it was decreased by inhibitors of PI3K, JNK, and p38 MAPK, but not by ERK1/2.

CONCLUSIONS

Resistin release from neutrophils was induced by both P. gingivalis-LPS and E. coli-LPS. This was decreased by CD14, CD18, and TLR4 and was dependent on PI3K, JNK, and p38 MAPK, but not on ERK1/2 in intracellular pathways of neutrophils.

Inflammatory effects of resistin on human smooth muscle cells: up-regulation of fractalkine and its receptor, CX3CR1 expression by TLR4 and Gi-protein pathways

In the atherosclerotic plaque, smooth muscle cells (SMC) acquire an inflammatory phenotype. Resistin and fractalkine (CX3CL1) are found in human atheroma and not in normal arteries. CX3CL1 and CX3CR1 are predominately associated with SMC. We have questioned whether resistin has a role in the expression of CX3CL1 and CX3CR1 in SMC thus contributing to the pro-inflammatory status of these cells. Cultured human aortic SMC were stimulated with 100 ng/ml resistin for 4, 6, 12, and 24 h, and then CX3CL1 and CX3CR1 expression was assessed by quantitative reverse transcription with the polymerase chain reaction and Western blot. We found that resistin up-regulated CX3CL1 and CX3CR1 in SMC and induced the phosphorylation of p38MAPK and STAT3. Inhibitors of p38MAPK, JAK-STAT, NF-kB, and AP-1 significantly reduced CX3CL1 and CX3CR1 expression. Knockdown of STAT1 and STAT3 with decoy oligodeoxinucleotides and the silencing of p65 and cjun with short interfering RNA decreased CX3CL1 and CX3CR1 expression. Anti-TLR4 antibody and pertussis toxin also reduced CX3CL1 and CX3CR1 protein expression. xCELLigence experiments revealed that resistin probably uses Gi-proteins for its effect on SMC. The CX3CL1 induced by resistin exhibited a chemotactic effect on monocyte transmigration. Thus, (1) resistin contributes to the pro-inflammatory state of SMC by the up-regulation of CX3CL1 and CX3CR1 expression via a mechanism involving NF-kB, AP-1, and STAT1/3 transcription factors, (2) resistin employs TLR4 and Gi-protein signaling for its effect on SMC, (3) CX3CL1 induced by resistin is functional in monocyte chemotaxis. The data reveal new mechanisms by which resistin promotes the inflammatory phenotype of SMC.

A novel pro-inflammatory mechanism of action of resistin in human endothelial cells: up-regulation of SOCS3 expression through STAT3 activation

Resistin is a significant local and systemic regulatory cytokine involved in inflammation. Suppressors of cytokine signaling (SOCS) proteins are intracellular regulators of receptor signal transduction induced by several cytokines in a cytokine and cell specific manner. Resistin up-regulates SOCS3 expression in mice adipocytes but it is not known whether this is a common occurrence in other cells. We questioned whether resistin-induces SOCS3 in human endothelial cells and if signal transducer and activator of transcription (STAT) proteins are involved in the process. The Real-Time PCR and Western blot analysis showed that in resistin-activated HEC the gene and protein expression of SOCS3 were significantly increased. Furthermore, resistin induced activation of STAT3 as characterized by increased tyrosine phosphorylation. Resistin-induced SOCS3 expression was blocked by specific inhibitors of STAT3 signaling and by the transfection of siRNA specific for STAT3. Silencing of SOCS3 gene expression by transfection with SOCS3 siRNA reduced the expression of resistin induced-P-selectin and fractalkine in HEC. Together, our results demonstrate that in HEC (1) resistin up-regulates SOCS3 expression and activates STAT3 transcription factor; (2) the increase in SOCS3 mRNA and protein expression as well as STAT3 activation have a long-lasting effect (up to 18h); (3) inhibition of SOCS3 function prevents resistin-induced expression of cell adhesion molecules P-selectin and fractalkine and thus activation of endothelial cells. The data uncover a new resistin-mediated mechanism in human endothelial cells and designate SOCS3 as a novel therapeutic target to modulate resistin-dependent inflammation in vessel wall diseases.

Quercetin and epigallocatechin gallate induce in vitro a dose-dependent stiffening and hyperpolarizing effect on the cell membrane of human mononuclear blood cells

The bioactivity of polyphenols is closely linked to their ability to interact with biological membranes. The study evaluates the in vitro effect of quercetin and epigallocatechin on the membrane anisotropy and transmembrane potential of peripheral blood mononuclear cells (PBMCs) isolated from 26 type 2 diabetes mellitus patients compared to 25 age matched controls. The in vitro assays were analyzed in correlation with the biochemical and inflammatory profile of the subjects and with insulin resistance parameters (HOMA-IR, plasma resistin) as well. For type 2 diabetes patients, the increase of HOMA-IR and resistin concentration was associated with a significant decrease of the PBMCs membrane anisotropy. The two tested polyphenols induced a dose-dependent hyperpolarizing effect and stiffening of the cell membranes for all tested subjects. Physiological levels of quercetin and epigallocatechin gallate had the tendency to normalize the PBMCs membrane anisotropy of the cells isolated from diabetes patients, bringing it to the level of cells isolated from normoglycemic ones. Epigallocatechin gallate induced higher effects compared to quercetin on the membranes isolated from subjects with higher cardiovascular risk. The decrease of membrane fluidity and the hyperpolarizing effect could explain the cardiovascular protective action of the tested compounds.

Resistin is associated with breach of tolerance and anti-nuclear antibodies in patients with hepatobiliary inflammation

Resistin is a cysteine-rich protein, which is abundantly expressed at the site of inflammation, and acts as a regulator of the NF-kB-dependent cytokine cascade. The aim of this study was to evaluate resistin levels in relation to inflammatory mediators, disease phenotype and autoantibody status in a spectrum of pathological conditions of the gastrointestinal tract. Resistin levels were measured with an ELISA in sera originated from 227 patients and 40 healthy controls (HC). Fifty patients diagnosed with non-alcoholic fatty liver disease (NAFLD), 53 ulcerative colitis (UC), 51 Crohn's disease (CD), 46 autoimmune hepatitis (AIH) and 27 primary sclerosing cholangitis (PSC) were included. The sera were analysed with respect to biochemical parameters of systemic inflammation and liver function and to the presence of antibodies to nuclear antigens (ANA), mitochondria (AMA) and smooth muscle (SMA). Compared with HC, resistin levels were raised in AIH (P = 0.017) and PSC (P = 0.03); compared with NAFLD, levels were elevated in CD (P = 0.041), AIH (P < 0.001) and PSC (P < 0.001). Patients with elevated levels of resistin were more often treated with corticosteroids, but no difference was found between active disease and clinical remission. Resistin levels were significantly higher in ANA-positive individuals compared with ANA-negative (P = 0.025). Resistin levels were directly correlated with IL-6 (r = 0.30, P = 0.02) and IL-8 (r = 0.51, P < 0.001). Elevated levels of resistin were prominent in patients with hepatobiliary inflammation and were associated with breach of self-tolerance, i.e. ANA positivity. Thus, we propose that resistin may be an important marker of disease severity in autoantibody-mediated gastrointestinal inflammatory diseases.

S100A4 deficiency is associated with efficient bacterial clearance and protects against joint destruction during Staphylococcal infection

BACKGROUND

Efficient host defense mechanisms are crucial for survival in sepsis and septic arthritis. S100 proteins are reported to have proinflammatory and bactericidal properties. The aim of this study was to investigate the role of S100A4 in staphylococcal arthritis.

METHODS

S100A4 knockout mice (S100A4KO) and wild-type counterparts (WT) were intravenously and intra-articularly challenged with Staphylococcus aureus strain LS-1. Clinical and morphological signs of arthritis and sepsis, phagocytosis, bone mineral density (BMD), and bone metabolism were then monitored in S100A4 and WT mice.

RESULTS

S100A4KO mice had a lower bacterial load in the kidneys than WT mice (P < .05) but developed more severe clinical signs of arthritis (P < .001) and had higher levels of interleukin 6 and L-selectin (P = .002). S100A4KO mice had fewer morphological signs of synovitis and cartilage/bone destruction following intra-articular instillation of bacteria. S100A4KO mice were protected from loss of BMD and had lower levels of RANKL, MMP3, and MMP9 (P < .05). S100A4 was not bactericidal in vitro.

CONCLUSIONS

In staphylococcal infection, S100A4 regulates bacterial clearance as well as systemic and local inflammatory responses.

Neutrophil-derived resistin release induced by Aggregatibacter actinomycetemcomitans

Resistin is an adipokine that induces insulin resistance in mice. In humans, resistin is not produced in adipocytes, but in various leukocytes instead, and it acts as a proinflammatory molecule. The present investigation demonstrated high levels of resistin in culture supernatants of neutrophils that are stimulated by a highly leukotoxic strain of Aggregatibacter actinomycetemcomitans. In contrast, the level of resistin was remarkably low when neutrophils were exposed to two other strains that produce minimal levels of leukotoxin and a further isogenic mutant strain incapable of producing leukotoxin. Pretreatment of neutrophils with a monoclonal antibody to CD18, β chain of lymphocyte function-associated molecule 1 (LFA-1), or an Src family tyrosine kinase inhibitor before incubation with the highly leukotoxic strain inhibited the release of resistin. These results show that A. actinomycetemcomitans-expressed leukotoxin induces extracellular release of human neutrophil-derived resistin by interacting with LFA-1 on the surface of neutrophils and, consequently, activating Src family tyrosine kinases.

Insulin suppresses endotoxin-induced oxidative, nitrosative, and inflammatory stress in humans

OBJECTIVE

To investigate whether insulin reduces the magnitude of oxidative, nitrosative, and inflammatory stress and tissue damage responses induced by endotoxin (lipopolysaccharide [LPS]).

RESEARCH DESIGN AND METHODS

Nine normal subjects were injected intravenously with 2 ng/kg LPS prepared from Escherichia coli. Ten others were infused with insulin (2 units/h) for 6 h in addition to the LPS injection along with 100 ml/h of 5% dextrose to maintain normoglycemia.

RESULTS

LPS injection induced a rapid increase in plasma concentrations of nitric oxide metabolites, nitrite and nitrate (NOM), and thiobarbituric acid-reacting substances (TBARS), an increase in reactive oxygen species (ROS) generation by polymorphonuclear leukocytes (PMNLs), and marked increases in plasma free fatty acids, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), macrophage migration inhibition factor (MIF), C-reactive protein, resistin, visfatin, lipopolysaccharide binding protein (LBP), high mobility group-B1 (HMG-B1), and myoglobin concentrations. The coinfusion of insulin led to a total elimination of the increase in NOM, free fatty acids, and TBARS and a significant reduction in ROS generation by PMNLs and plasma MIF, visfatin, and myoglobin concentrations. Insulin did not affect TNF-α, MCP-1, IL-6, LBP, resistin, and HMG-B1 increases induced by the LPS.

CONCLUSIONS

Insulin reduces significantly several key mediators of oxidative, nitrosative, and inflammatory stress and tissue damage induced by LPS. These effects of insulin require further investigation for its potential use as anti-inflammatory therapy for endotoxemia.

Regulation of adipokine production in human adipose tissue by propionic acid

BACKGROUND

Dietary fibre (DF) has been shown to be protective for the development of obesity, insulin resistance and type 2 diabetes. Short-chain fatty acids, produced by colonic fermentation of DF might mediate this beneficial effect. Adipose tissue plays a key role in the regulation of energy homeostasis, therefore, we investigated the influence of the short-chain fatty acid propionic acid (PA) on leptin, adiponectin and resistin production by human omental (OAT) and subcutaneous adipose tissue (SAT). As PA has been shown to be a ligand for G-protein coupled receptor (GPCR) 41 and 43, we investigated the role of GPCR's in PA signalling.

MATERIALS AND METHODS

Human OAT and SAT explants were obtained from gynaecological patients who underwent surgery. Explants were incubated for 24 h with PA. Adipokine secretion and mRNA expression were determined using ELISA and RT-PCR respectively.

RESULTS

We found that PA significantly stimulated leptin mRNA expression and secretion by OAT and SAT, whereas it had no effect on adiponectin. Furthermore, PA reduced resistin mRNA expression. Leptin induction, but not resistin reduction, was abolished by inhibition of Gi/o-coupled GPCR signalling. Moreover, GPCR41 and GPCR43 mRNA levels were considerably higher in SAT than in OAT.

CONCLUSIONS

We demonstrate that PA stimulates expression of the anorexigenic hormone leptin and reduces the pro-inflammatory factor resistin in human adipose tissue depots. This suggests that PA is involved in regulation of human energy metabolism and inflammation and in this way may influence the development of obesity and type 2 diabetes.

Immune dysfunction in uremia

Kidney dysfunction leads to disturbed renal metabolic activities and to impaired glomerular filtration, resulting in the retention of toxic solutes affecting all organs of the body. Cardiovascular disease (CVD) and infections are the main causes for the increased occurrence of morbidity and mortality among patients with chronic kidney disease (CKD). Both complications are directly or indirectly linked to a compromised immune defense. The specific coordinated roles of polymorphonuclear leukocytes (PMNLs), monocytes/macrophages, lymphocytes and antigen-presenting cells (APCs) in maintaining an efficient immune response are affected. Their normal response can be impaired, giving rise to infectious diseases or pre-activated/primed, leading to inflammation and consequently to CVD. Whereas the coordinated removal via apoptosis of activated immune cells is crucial for the resolution of inflammation, inappropriately high apoptotic rates lead to a diminished immune response. In uremia, the balance between pro- and anti-inflammatory and between pro- and anti-apoptotic factors is disturbed. This review summarizes the interrelated parameters interfering with the immune response in uremia, with a special focus on the non-specific immune response and the role of uremic toxins.