The involvement of the monocytes/macrophages in chronic inflammation associated with atherosclerosis

Atherosclerosis is a progressive chronic disease of large and medium arteries, characterized by the formation of atherosclerotic plaques. Monocytes and macrophages are key factors in lesion development, participating to the processes that mediate the progression of the atherosclerotic plaque (lipid accumulation, secretion of pro-inflammatory and cytotoxic factors, extracellular matrix remodeling). The recruitment of the monocytes in the vascular wall represents a hallmark in the pathology of the atherosclerotic lesion. Monocyte adhesion and transmigration are dependent on the complementary adhesion molecules expressed on the endothelial surface, whose expression is modulated by chemical mediators. The atherosclerotic plaque is characterized by a heterogeneous population of macrophages reflecting the complexity and diversity of the micro-environment to which cells are exposed after entering the arterial wall. Within the atherosclerotic lesions, macrophages differentiate, proliferate and undergo apoptosis. Taking into account that their behavior has a direct and critical influence on all lesional stages, the development of therapeutic approaches to target monocytes/macrophages in the atherosclerotic plaque became a focal interest point for researchers in the field.     

Diet-induced aortic atherosclerosis in Malaysian long-tailed monkeys (Macaca irus).

Moderate hypercholesterolaemia has been produced in eight adult male M. irus monkeys by feeding an egg-toast preparation containing butter and 0.14 per cent. total cholesterol. At autopsy, after two to four years of persistent hypercholesterolaemia, there was massive fatty streaking of the aorta involving 21 to 78 per cent. of the intimal surface. The distribution and morphology of the fatty streaks was similar to that in man. In addition, there were fibrous plaques including "soft" lipid-rich atherosclerotic plaques identical to their human counterpart. There was no grossly detectable thromobosis, haemorrhage or ulceration. Atherosclerotic lesions were also present in the coronary, carotid, subclavian, iliac and femoral arteries. In a control group of monkeys fed a low-fat, cholesterol-free diet, arterial lesions were identical in type and extent to those in freshly captured wild monkeys.     

Chronic coronary periarteritis in two patients with chronic periaortitis

Two cases of chronic coronary periarteritis associated with chronic periaortitis are described. In one, the chronic periaortitis took the form of perianeurysmal fibrosis around a thoracic atherosclerotic aneurysm; in the other it resembled idiopathic retroperitoneal fibrosis. The findings in the two subjects support the unifying concept of chronic periaortitis, to include conditions previously known as idiopathic retroperitoneal or mediastinal fibrosis, perianeurysmal retroperitoneal fibrosis and inflammatory aneurysms of the aorta. The observations are also compatible with the view that the disease is due to hypersensitivity to atheroma.     

Immunohistochemical characterization of inflammatory cells associated with advanced atherosclerosis

During repair of 12 atherosclerotic abdominal aortic aneurysms, fresh samples of aneurysm wall were obtained. Histology confirmed the presence of advanced atherosclerosis associated with medial thinning and a variable aortic adventitial chronic inflammatory cell infiltrate. Monoclonal antibodies were used to identify the inflammatory cells throughout the aortic wall. The majority of lymphocytes in the aortic adventitia were B-cells. B-cells were not present in atheromatous plaques. T-cells, predominantly T-helper cells, were found in atheromatous plaques and in aortic adventitia. The majority of lymphocytes and macrophages in aortic adventitia and most vascular endothelial cells were HLA-DR positive. Ki-67 staining was found in B-cells and T-helper cells, indicating that these cells were proliferating. Occasional lymphocytes were BerH2 positive, indicating that some lymphocytes were activated. These findings suggest that chronic periaortitis is an active, immunologically mediated, local complication of advanced human atherosclerosis.     

Cytokine actions in growth disorders associated with pediatric chronic inflammatory diseases (review)

Growth disorders are commonly observed in children suffering from chronic inflammatory diseases such as Juvenile Idiopathic Arthritis (JIA) and Inflammatory Bowel Disease (IBD). These disorders range from general growth retardation to local acceleration of growth in the affected limb and are associated with the increased production of pro-inflammatory cytokines. In this article, we review how cytokines influence child growth by exerting a local effect at the level of the growth plate, and through systemic effects throughout the whole body.     

Cytokine gene polymorphism in Iranian patients with chronic myelogenous leukaemia

Chronic myelogenous leukaemia (CML) is a disorder of the haematopoietic stem cell that results in malignant expansion of myeloid cells with a cytogenetic abnormality, and translocation between chromosomes 9 and 22, known as the Philadelphia chromosome. It has been hypothesized that genetic factors other than histocompatibility disparity may play a role in predisposition to developing CML. In this regard, T helper types 1 and 2 (Th1 and Th2) cytokines and their gene polymorphism seem to be important. Overall expression and secretion of cytokines are dependent, at least in part, on genetic polymorphism (nucleotide variations) within the promoter region or other regulatory sequences of cytokine genes. The majority of polymorphisms described are single nucleotide polymorphism (SNPs). The objective of this study was to analyse the genetic profile of Th1 and Th2 cytokines in 30 Iranian patients with CML and 40 healthy subjects. In the patients and control subjects, the allelic and genotype frequencies were determined for the cytokine genes. All typing were performed with a polymerase chain reaction-sequence-specific primers (PCR-SSP) assay. Allele and genotype frequencies were calculated and compared with those of normal controls. The results showed that the most frequent genotypes in our patients were transforming growth factor (TGF)-beta TG/TG, interferon (IFN)-gamma AT, interleukin (IL)-4 CC at position -590, TT at position -33, and IL-10 ACC/ACC and ATA/ATA. In contrast, the genotypes TGF-beta CG/CG, IL-2 TT at position -330, IL-4 CT at position -590, CT at position -33, and IL-10 GCC/ACC were seen at much lower frequencies. The results suggest that production of TGF-beta in CML patients is higher and production of IL-4 and IL-10 is lower than in normal subjects.     

IRF4 selectively controls cytokine gene expression in chronic intestinal inflammation

The authors previously showed that interferon regulatory factor (IRF)4 knockout mice are protected from experimental oxazolone and TNBS colitis. Here the effect of IRF4 on the expression of pro- and anti-inflammatory cytokines in TNBS colitis and long-term CD45RB^high transfer colitis is examined. In TNBS colitis, no differences were found in interleukin (IL)-18 and tumor necrosis factor (TNF)-α expression between IRF4 knockout and wild-type mice. However, significant differences were detected in IL-6 and IL-17 production. Upon treatment with hyper-IL-6, IRF4^–/– mice lost their protective properties towards TNBS application. Hyper-IL-6 application induced IL-6 mRNA, but not IL-17 mRNA expression, suggesting that IL-6 deficiency is not primarily responsible for the lack of IL-17 production. T-bet and GATA-3 mRNA expressions were not affected upon IL-6 application. In transfer colitis, colonic cytokine mRNA analysis revealed a reduced production of IL-6 in IRF4^–/– reconstituted mice in the long-term course. In contrast, several other cytokines did not differ between the two groups (e.g. TNF-α and IL-10). Measurement of supernatants from splenic mononuclear cells revealed a significant difference in IL-6 and IL-17 production between the two groups. These findings suggest that IRF4 selectively regulates cytokine gene expression in chronic inflammation. IRF4 therefore emerges as an attractive target for the therapy of chronic intestinal inflammation. Blocking IRF4 might be an interesting option to modulate inflammation in the advanced state of inflammation.     

Galectin-3 gene inactivation reduces atherosclerotic lesions and adventitial inflammation in ApoE-deficient mice

This study has examined the role of galectin-3 (GaL3), a multicompartmented N-acetyllactosamine-binding chimeric lectin, on atherogenesis in the ApoE-deficient mouse model of atherosclerosis. Pathological changes consisting of atheromatous plaques, atherosclerotic microaneurysms extending into periaortic vascular channels, and adventitial and periaortic inflammatory infiltrates were assessed in an equal number (n = 36) of apolipoprotein (Apo)E-deficient mice and ApoE-GaL3 double-knockout mice. These mice were divided into three age groups, 21 to 23 weeks, 25 to 31 weeks, and 36 to 44 weeks of age. Results of this morphological analysis have shown an age-related increase in the incidence of aorta atheromatous plaques and periaortic vascular channels in ApoE-deficient mice. By contrast ApoE/GaL3 double-knockout mice did not show an increase in pathological changes with age. The 36- to 44-week group of ApoE(-/-)/GaL3(-/-) mice had a significantly lower number of atherosclerotic lesions (P < 0.004) and fewer atheromatous plaques (P < 0.008) when compared with ApoE(-/-)/GaL3+/+ mice of the same age. ApoE(-/-)/GaL3(-/-) mice had a lower number of perivascular inflammatory infiltrates and mast cells than those found in ApoE(-/-)/GaL3+/+ mice. The reduced number of perivascular mast cells may have resulted in a low level of interleukin-4 that contributed to the reduction in the morphological parameters of atherogenesis correlated with the lack of GaL3 expression. The effect of GaL3 deficiency on atherogenesis decrease could be related to its function as a multifunctional protein implicated in macrophage chemotaxis, angiogenesis, lipid loading, and inflammation.     

Cytokine gene polymorphisms associated with symptomatic parvovirus B19 infection

BACKGROUND: The immune system has been implicated in the pathogenesis of certain clinical manifestations of parvovirus B19 infection, including rash and arthralgia. Cytokines feature in the pathogenesis of parvovirus B19 infection, so inherited variability in cytokine responses to B19 infection might have a bearing on the symptomatology of parvovirus B19 infection. AIMS: To investigate the possible role of cytokine gene polymorphisms in the clinical manifestations of parvovirus B19 infection. METHODS: Thirty six patients with a variety of symptoms at acute infection and follow up (mean, 22.0 months) and controls (99-330, depending on the locus) were examined for the following cytokine polymorphisms: tumour necrosis factor alpha (TNF alpha), -308; interferon gamma (IFN-gamma), +874; interleukin 6 (IL-6), -174; IL-10, -592, -819, and -1082; and transforming growth factor beta1 (TGF beta 1), +869 (codon 10) and +915 (codon 25). RESULTS: The TNF alpha -308*A allele occurred in 13.9% of the parvovirus group compared with 27.0% of the control group (odds ratio (OR), 0.44; p = 0.02). The TGF beta 1 CG/CG haplotype was more frequent in the parvovirus group than in the controls (16.7% v 5%; OR, 4.8; p = 0.02). Within the B19 infected group, the TGF beta 1 +869 T allele was associated with skin rash at acute infection (p = 0.005), whereas at follow up the IFN-gamma +874 T allele was associated with the development of anti-B19 non-structural protein 1 antibodies (p = 0.04). CONCLUSIONS: The results of the present study suggest that inherited variability in cytokine responses may affect the likelihood of developing symptoms during parvovirus infection.     

Chronic inflammation during osteoarthritis is associated with an increased expression of CD161 during advanced stage

Increasing evidence suggests a role of inflammation during the pathogenesis of osteoarthritis (OA). The local and systemic inflammation was studied in 33 patients of different KL grades, grade2 (n = 11), grade3 (n = 6) and grade4 (n = 16). The levels of cytokines, adipokines and matrix metalloproteinases (MMPs) were measured in serum and synovial fluid (SF) by flow cytometry and ELISA, respectively. The frequency of T cells and CD161 expression was measured by flow cytometry. The levels of IL‐1β, IL‐6 and IL‐10 were significantly higher in sera and SF of patients with OA as compared to healthy control's serum. Higher levels of MMP9 and leptin and lower levels of adiponectin were observed in SF as compared to serum. The MMP9 in SF and MMP13 levels in serum and SF decreased in KL grade 4 cases. In these patients, higher levels of leptin and lower levels of adiponectin were observed in SF versus patients of lower grades. There was increased infiltration of CD8+ T cells in SF of OA cases with decreased frequency in grade 4 cases. The expression of CD161 on T cells was significantly higher in SF than peripheral blood with significant upregulation in grade 4 patients. The CD161 expression had significant positive correlation with IL‐17 in the serum of patients. The ROC curves of CD161 expression significantly distinguished grade 2 and grade 4 patients. Collectively, an elevated CD161 expression on T cells in circulation and synovial compartment clearly distinguished lower and higher grade patients warranting studies to assess its role as a contributing factor towards OA progression.     

Cytokine production associated with periportal fibrosis during chronic schistosomiasis mansoni in humans

Volunteers living in an area where schistosomiasis mansoni is endemic were subjected to ultrasound examination and classified into groups according to the levels of fibrosis diagnosed, namely, absence of indications of fibrosis (group 0), incipient fibrosis (group 1), and moderate/severe fibrosis (group 2). Peripheral blood mononuclear cells (PBMC) collected from the volunteers were stimulated with soluble antigens from adult schistosomes or from schistosome eggs, and the production of the cytokines gamma interferon, tumor necrosis factor alpha, transforming growth factor beta (TGF-beta), interleukin-4 (IL-4), IL-10, and IL-13 was determined. Potential associations of the level of fibrosis with age, sex, intensity of infection, and cytokine production were investigated between the three groups. Univariate analysis identified associations of age (>50), gender (male), and absence of eggs/g of feces with moderate/severe fibrosis and an association of intensity of infection (>100 eggs) with incipient fibrosis. When cytokine production in PBMC cultures stimulated by soluble egg antigens was categorized as low or high, significant differences in the distribution of IL-13 levels were established between groups 0 and 2. No significant differences were detected between the groups in the cytokines produced by PBMC cultures stimulated with soluble antigens from adult schistosomes. When all variables were tested in multivariate analyses, only IL-13 was strongly associated with fibrosis (odds ratio = 5.8; 95% confidence interval [CI] = 1.1 to 30.5). While high levels of TGF-beta appeared to be associated with protection against fibrosis, the strength of the association was low.     

Cytokine mRNA expression in lymphoid organs associated with the expression of IgA response in the rat

The T-helper dependency of the IgA antibody response has been investigated in rats injected intravenously with Schistosoma mansoni eggs. This method, allowing the trapping of parasite eggs in the lung tissue, led to a strong anti-egg IgA antibody response in the bronchoalveolar lavage but not in the serum. To characterize the cytokine pattern associated with the IgA response, kinetic analysis of the cytokine mRNA expression in the lungs, periaortic nodes (PN) and spleen was undertaken. Under such conditions, significant levels of mRNA encoding IL-5 and IL-10 were recorded in spleen during the early period following egg injection, as well as a more prolonged expression of TGF-beta and IL-6 mRNAs. However, neither IFN-gamma nor IL-4 mRNA could be detected in these samples. Finally, in lungs and in PN, RT-PCR analysis revealed delayed production of cytokine mRNA. Taken together our data suggest that the rat mucosal IgA antibody response is predominantly linked to a Th2 response.     

Gene expression profiles associated with advanced pancreatic cancer

Few studies have addressed the expression profiles associated with progression of pancreatic cancer to advanced disease. Towards this end, we performed expression profiling of a series of normal pancreas, pancreatitis and cancer tissues representing early stage resected pancreatic cancers (stages pT2/T3), late stage unresectable cancers (stage pT4) and matched metastases to a variety of organ sites. Microarray data was analyzed using linear modeling of microarray data (LIMMA), and differentially expressed genes were subjected to Gene Set Enrichment Analysis (GSEA). While robust differences were found in primary cancers as compared to normal pancreatic tissues, no differences were found between primary cancers and metastases, whether using matched or unmatched samples. When resected pancreatic cancers were specifically compared to advanced pancreatic cancers, significant differences in gene expression were found associated with growth at the primary site. These differentially expressed genes were most prominent in gene classes that related to MAPK and Wnt pathway, metabolism, immune regulation, cell-cell and cell-matrix interactions within the infiltrating carcinoma. One candidate upregulated gene (MXI1) was validated as having increased expression in advanced stage (T4) carcinomas by real-time PCR (p<0.05) and immunolabeling (p<0.003). We conclude that in addition to the robust changes in expression that accompany pancreatic carcinogenesis additional specific changes occur in association with growth at the primary site. By contrast, metastatic spread is not accompanied by reproducible changes in gene expression. These findings add to our understanding of pancreatic cancer and offer new topics for investigation into the aggressive nature of this deadly tumor type.     

Meta-analysis of gene expression in the mouse liver reveals biomarkers associated with inflammation increased early during aging

Aging is associated with a loss of cellular homeostasis, a decline in physiological function and an increase in various pathologies. Employing a meta-analysis, hepatic gene expression profiles from four independent mouse aging studies were interrogated. There was little overlap in the number of genes or canonical pathways perturbed, suggesting that independent study-specific factors may play a significant role in determining age-dependent gene expression. However, 43 genes were consistently altered during aging in three or four of these studies, including those that (1) exhibited progressively increased expression starting from 12 months of age, (2) exhibited similar expression changes in models of progeria at young ages and dampened or no changes in old longevity mouse models, (3) were associated with inflammatory tertiary lymphoid neogenesis (TLN) associated with formation of ectopic lymphoid structures observed in chronically inflamed tissues, and (4) overlapped with genes perturbed by aging in brain, muscle, and lung. Surprisingly, around half of the genes altered by aging in wild-type mice exhibited similar expression changes in adult long-lived mice compared to wild-type controls, including those associated with intermediary metabolism and feminization of the male-dependent gene expression pattern. Genes unique to aging in wild-type mice included those linked to TLN.     

Changes in colon gene expression associated with increased colon inflammation in interleukin-10 gene-deficient mice inoculated with Enterococcus species

Background

Inappropriate responses to normal intestinal bacteria may be involved in the development of Inflammatory Bowel Diseases (IBD, e.g. Crohn's Disease (CD), Ulcerative Colitis (UC)) and variations in the host genome may mediate this process. IL-10 gene-deficient (Il10 ^-/- ) mice develop CD-like colitis mainly in the colon, in part due to inappropriate responses to normal intestinal bacteria including Enterococcus strains, and have therefore been used as an animal model of CD. Comprehensive characterization of changes in cecum gene expression levels associated with inflammation in the Il10 ^-/- mouse model has recently been reported. Our aim was to characterize changes in colonic gene expression levels in Il10 ^-/- and C57BL/6J (C57; control) mice resulting from oral bacterial inoculation with 12 Enterococcus faecalis and faecium (EF) strains isolated from calves or poultry, complex intestinal flora (CIF) collected from healthy control mice, or a mixture of the two (EF·CIF). We investigated two hypotheses: (1) that oral inoculation of Il10 ^-/- mice would result in greater and more consistent intestinal inflammation than that observed in Il10 ^-/- mice not receiving this inoculation, and (2) that this inflammation would be associated with changes in colon gene expression levels similar to those previously observed in human studies, and these mice would therefore be an appropriate model for human CD.

Results

At 12 weeks of age, total RNA extracted from intact colon was hybridized to Agilent 44 k mouse arrays. Differentially expressed genes were identified using linear models for microarray analysis (Bioconductor), and these genes were clustered using GeneSpring GX and Ingenuity Pathways Analysis software. Intestinal inflammation was increased in Il10 ^-/- mice as a result of inoculation, with the strongest effect being in the EF and EF·CIF groups. Genes differentially expressed in Il10 ^-/- mice as a result of EF or EF·CIF inoculation were associated with the following pathways: inflammatory disease (111 genes differentially expressed), immune response (209 genes), antigen presentation (11 genes, particularly major histocompatability complex Class II), fatty acid metabolism (30 genes) and detoxification (31 genes).

Conclusions

Our results suggest that colonic inflammation in Il10 ^-/- mice inoculated with solutions containing Enterococcus strains is associated with gene expression changes similar to those of human IBD, specifically CD, and that with the EF·CIF inoculum in particular this is an appropriate model to investigate food-gene interactions relevant to human CD.     

Cytokine expression profiles of immune imbalance in post-mononucleosis chronic fatigue

ABSTRACT: BACKGROUND: As Chronic Fatigue Syndrome (CFS) has been known to follow Epstein-Bar virus (EBV) and other systemic infections; our objective was to describe differences in immune activation in post-infective CFS (PI-CFS) patients and recovered controls. We studied 301 adolescents prospectively over 24 months following the diagnosis of monospot-positive infectious mononucleosis (IM). We found an incidence of CFS at 6, 12 and 24 months of 13%, 7% and 4% respectively. METHODS: Using chemiluminescent imaging we measured the concentrations of IL-1a, 1b, 2, 4, 5, 6, 8, 10, 12 (p70), 13, 15, 17 and 23, IFN-gamma, TNF-alpha and TNF-beta in duplicate plasma samples available in bio-bank from 9 PI-CFS subjects and 12 recovered controls at 24 months post-infection. RESULTS: Standard comparative analysis indicated significant differences in IL-8 and 23 across subject groups. In constructing a linear classification model IL-6, 8 and 23 were selected by two different statistical approaches as discriminating features, with IL-1a, IL-2 and IFN-gamma also selected in one model or the other. This supported an assignment accuracy of better than 80% at a confidence level of 0.95 into PI-CFS versus recovered controls. CONCLUSION: These results suggest that co-expression patterns in as few as 5 cytokines associated with Th17 function may hold promise as a tool for the diagnosis of post-infectious CFS.     

Neutrophilic myeloperoxidase-macrophage interactions perpetuate chronic inflammation associated with experimental arthritis

Rheumatoid arthritis is a systemic disease of unknown etiology. The purpose of this study was to elucidate an unrecognized interaction between neutrophilic myeloperoxidase (MPO) and macrophages (Mphi) which could perpetuate the inflammatory response associated with arthritis. A monoarticular arthritis was induced by intra-articular injection of group A streptococcus cell wall fragments (PG-APS) into the ankle joint of female Lewis rats. After swelling/erythema subsided, joints were reinjected with either recombinant MPO or enzymatically inactive MPO (iMPO). Joint measurements were made daily and arthritis was confirmed by histology. Neither iMPO nor MPO could initiate "clinical" arthritis; however, either form of the enzyme injected after PG-APS induced a dose-dependent increase in erythema and swelling. Mannans, which block the binding of MPO to Mo, ablated clinical symptoms. Also, the presence of tumor necrosis factor alpha was observed only in diseased joints using immunocytochemistry.     

Vascular prosthetic implantation is associated with prolonged inflammation following aortic aneurysm surgery

The purpose of this study was to semiquantify the magnitude of surgical stress in patients undergoing aortic surgery by measuring inflammatory responses perioperatively, focusing on cytokine secretion. Serum concentrations of interleukin (IL) 1, IL-6, IL-8, and tumor necrotizing factor (TNF) were measured in patients undergoing abdominal or thoracic aortic aneurysmectomy preoperatively and periodically thereafter for 2 weeks. Urinary trypsin inhibitor (UTI/Cr) and C-reactive protein (CRP) concentration and the systemic inflammatory response syndrome (SIRS) score also were determined. Indices of inflammation and cytokine concentrations peaked at 1–3 days after surgery and decreased thereafter; however, IL-8 increased again after day 7. Concentrations of IL-8, UTI/Cr, and CRP and the SIRS score were still higher 14 days after surgery than preoperatively. The maximum concentrations of IL-6 and IL-8 were higher after thoracic than abdominal aortic repair; however, the maximum values of cytokines were not correlated with operative factors in all patients. A patient suffering from graft infection showed an increase in cytokine concentrations on day 7. The inflammatory response does not return to preoperative values within 2 weeks of surgery in patients undergoing thoracic or abdominal aortic aneurysm repair. The prolonged secretion of IL-8 suggests a host reaction to the synthetic prosthesis. A large increase in inflammatory cytokines on day 7 may indicate infection of the vascular graft.