Marta Czesnikiewicz-Guzik

T cell subset-specific susceptibility to aging.

With increasing age, the competence of the immune system to fight infections and tumors declines. Age-dependent changes have been mostly described for human CD8 T cells, raising the question of whether the response patterns for CD4 T cells are different. Gene expression arrays of memory CD4 T cells yielded a similar age-induced fingerprint as has been described for CD8 T cells. In cross-sectional studies, the phenotypic changes were not qualitatively different for CD4 and CD8 T cells, but occurred much more frequently in CD8 T cells. Homeostatic stability partially explained this lesser age sensitivity of CD4 T cells. With aging, naïve and central memory CD8 T cells were lost at the expense of phenotypically distinct CD8 effector T cells, while effector CD4 T cells did not accumulate. However, phenotypic shifts on central memory T cells were also more pronounced in CD8 T cells. This distinct stability in cell surface marker expression can be reproduced in vitro. The data show that CD8 T cells are age sensitive by at least two partially independent mechanisms: fragile homeostatic control and gene expression instability in a large set of regulatory cell surface molecules.

Regulation of T cell receptor signaling by activation-induced zinc influx

Zinc enhances TCR signaling in part by inhibiting Shp-1 recruitment to the TCR synapse.

Implications of oral Helicobacter pylori for the outcome of its gastric eradication therapy.

Background and Aims Helicobacter pylori (H. pylori) is an important pathogen in gastritis, peptic ulcer and possibly gastric cancer, but several questions remain unanswered. Particularly how the organism is transmitted and what is the relationship between oral presence of H. pylori and the gastric infection. Accordingly, we aimed to characterize the H. pylori in oral cavity and to evaluate its relationship to gastric H. pylori infection. Materials and Methods Out of total 100 screened for H. pylori infection female subjects (40 to 85 y), 49 patients (pts), who had positive 13C-urea breath test (UBT) and dyspeptic symptoms, agreed for 1 week regimen of triple anti-H. pylori therapy. The presence of H. pylori in oral cavity was assessed using bacterial culture from saliva and gingival pockets. Gastric H. pylori infection was estimated using capsulated 13C-urea breath test and plasma anti-H. pylori IgG and saliva IgA antibodies. In addition, plasma gastrin, ghrelin, and pepsinogen I were measured by radioimmunoassay. In selected patients, gastroscopy was additionally performed and gastric biopsy samples were taken for H. pylori random amplification of polymorphic DNA genetic profiling. Results The triple therapy resulted in gastric H. pylori eradication in 79% pts, along with significant decrease of plasma gastrin combined with an increase in plasma ghrelin and pepsinogen I (PgI) levels and a marked alleviation of dyspeptic symptoms. In contrast to gastric effects, the eradication therapy failed to cause any changes in the presence of H. pylori in oral cavity. Moreover no relationship was observed between the presence of H. pylori in oral cavity and the gastric H. pylori eradication. In line with these findings, no relationship between gastric and oral H. pylori was found using genetic profiling by random amplification of polymorphic DNA. Conclusions H. pylori was detected both in the oral cavity and the stomach but oral H. pylori had no relation to gastric H. pylori and remained unaffected by eradication of gastric H. pylori.

Age-Dependent Signature of Metallothionein Expression in Primary CD4 T Cell Responses Is Due to Sustained Zinc Signaling

The ability to mount adaptive immune responses to vaccinations and viral infections declines with increasing age. To identify mechanisms leading to immunosenescence, primary CD4 T cell responses were examined in 60- to 75-year-old individuals lacking overt functional defects. Transcriptome analysis indicated a selective defect in zinc homeostasis. CD4 T cell activation was associated with zinc influx via the zinc transporter Zip6, leading to increased free cytoplasmic zinc and activation of negative feedback loops, including the induction of zinc-binding metallothioneins. In young adults, activation-induced cytoplasmic zinc concentrations declined after 2 days to below prestimulation levels. In contrast, activated naïve CD4 T cells from older individuals failed to downregulate cytoplasmic zinc, resulting in excessive induction of metallothioneins. Activation-induced metallothioneins regulated the redox state in activated T cells and accounted for an increased proliferation of old CD4 T cells, suggesting that regulation of T cell zinc homeostasis functions as a compensatory mechanism to preserve the replicative potential of naïve CD4 T cells with age.

Antiatherosclerotic effect of Ang- (1-7) non-peptide mimetic (AVE 0991) is mediated by inhibition of perivascular and plaque inflammation in early atherosclerosis.

Inflammation plays a key role in atherosclerosis. The protective role of angiotensin 1–7 (Ang‐(1–7)) in vascular pathologies suggested the therapeutic use of low MW, non‐peptide Ang‐(1–7) mimetics, such as AVE0991. The mechanisms underlying the vaso‐protective effects of AVE0991, a Mas receptor agonist, remain to be explored.

Hypertension: Focus on autoimmunity and oxidative stress

Understanding the causal role of the immune and inflammatory responses in hypertension has led to questions regarding the links between hypertension and autoimmunity. Immune pathology in primary hypertension mimics several autoimmune mechanisms observed in the pathogenesis of systemic lupus erythematosus, psoriasis, systemic sclerosis, rheumatoid arthritis and periodontitis. More importantly, the prevalence of hypertension in patients with these autoimmune diseases is significantly increased, when compared to control populations. Clinical and epidemiological evidence is reviewed along with possible mechanisms linking hypertension and autoimmunity. Inflammation and oxidative stress are linked in a self-perpetuating cycle that significantly contributes to the vascular dysfunction and renal damage associated with hypertension. T cell, B cell, macrophage and NK cell infiltration into these organs is essential for this pathology. Effector cytokines such as IFN-γ, TNF-α and IL-17 affect Na+/H+ exchangers in the kidney. In blood vessels, they lead to endothelial dysfunction and loss of nitric oxide bioavailability and cause vasoconstriction. Both renal and vascular effects are, in part, mediated through induction of reactive oxygen species-producing enzymes such as superoxide anion generating NADPH oxidases and dysfunction of anti-oxidant systems. These mechanisms have recently become important therapeutic targets of novel therapies focused on scavenging oxidative (isolevuglandin) modification of neo-antigenic peptides. Effects of classical immune targeted therapies focused on immunosuppression and anti-cytokine treatments are also reviewed.

Hypertension and increased endothelial mechanical stretch promote monocyte differentiation and activation: roles of STAT3, interleukin 6 and hydrogen peroxide

Abstract Aims Monocytes play an important role in hypertension. Circulating monocytes in humans exist as classical, intermediate, and non-classical forms. Monocyte differentiation can be influenced by the endothelium, which in turn is activated in hypertension by mechanical stretch. We sought to examine the role of increased endothelial stretch and hypertension on monocyte phenotype and function. Methods and results Human monocytes were cultured with confluent human aortic endothelial cells undergoing either 5% or 10% cyclical stretch. We also characterized circulating monocytes in normotensive and hypertensive humans. In addition, we quantified accumulation of activated monocytes and monocyte-derived cells in aortas and kidneys of mice with Angiotensin II-induced hypertension. Increased endothelial stretch enhanced monocyte conversion to CD14++CD16+ intermediate monocytes and monocytes bearing the CD209 marker and markedly stimulated monocyte mRNA expression of interleukin (IL)-6, IL-1β, IL-23, chemokine (C-C motif) ligand 4, and tumour necrosis factor α. STAT3 in monocytes was activated by increased endothelial stretch. Inhibition of STAT3, neutralization of IL-6 and scavenging of hydrogen peroxide prevented formation of intermediate monocytes in response to increased endothelial stretch. We also found evidence that nitric oxide (NO) inhibits formation of intermediate monocytes and STAT3 activation. In vivo studies demonstrated that humans with hypertension have increased intermediate and non-classical monocytes and that intermediate monocytes demonstrate evidence of STAT3 activation. Mice with experimental hypertension exhibit increased aortic and renal infiltration of monocytes, dendritic cells, and macrophages with activated STAT3. Conclusions These findings provide insight into how monocytes are activated by the vascular endothelium during hypertension. This is likely in part due to a loss of NO signalling and increased release of IL-6 and hydrogen peroxide by the dysfunctional endothelium and a parallel increase in STAT activation in adjacent monocytes. Interventions to enhance bioavailable NO, reduce IL-6 or hydrogen peroxide production or to inhibit STAT3 may have anti-inflammatory roles in hypertension and related conditions.

Microvascular dysfunction in ankylosing spondylitis is associated with disease activity and is improved by anti-TNF treatment

Ankylosing spondylitis (AS) is associated with high cardiovascular morbidity and mortality. Recent studies indicate that microvascular dysfunction may underlie cardiovascular risk in AS. We hypothesized, that microvascular morphology and dysfunction is linked to AS activity and is modifiable by TNF-α inhibitor (TNFi) treatment. Functional Laser Doppler Flowmetry with post-occlusive reactive hyperemia, and structural nailfold capillaroscopy were performed in 54 patients with AS and 28 matched controls. Active AS was diagnosed based on BASDAI ≥ 4 (n = 37). Effects of 3-month TNFi on microcirculation in active AS were studied. AS was associated with prolonged time to peak hyperemia compared to healthy controls. High disease activity was associated with increased time to peak hyperemia and decreased peak hyperemia when compared to patients with inactive AS. In capillaroscopy, AS was associated with morphological abnormalities indicating increased neoangiogenesis and pericapillary edema compared to controls. Microvascular function improved following 3 months of TNFi in reference to basal flow as well as post-occlusive parameters. TNFi reduced pericapillary edema, while other parameters of capillary morphology remained unchanged. Microvascular dysfunction and capillary neovascular formation are associated with disease activity of AS. Anti-TNF-α treatment may restore microcirculation function and capillary edema but does not modify microvascular structural parameters.

Scientists on the Spot: Salt, the microbiome, and cardiovascular diseases

Marta Czesnikiewicz-Guzik: Good afternoon, my name is Marta Czesnikiewicz-Guzik and I am from the Department of Periodontology at Glasgow University. I have the pleasure of hosting today for this special European Society of Cardiology edition of Cardiovascular Research Onlife, Professor Dominik Müller from the Experimental and Clinical Research Centre in Berlin. Dominik has significantly contributed to our understanding of the links between salt, immunity, and cardiovascular diseases, and also our understanding of how the gut microbiota contributes to this picture. Welcome Dominik, and thank you very much for joining us at Cardiovascular Research.

The effect of the treatment of denture related stomatitis on peripheral T cells and monocytes

PURPOSE Systemic immune activation has been recently linked to chronic inflammatory disorders of the oral cavity, particularly to periodontitis. The purpose of this study was to determine whether treatment of a fungus-induced oral inflammation, namely denture-related stomatitis (DRS), can affect the activation of the systemic immune response. MATERIALS AND METHODS Peripheral blood from patients with denture-related stomatitis caused by Candida albicans infection (n = 15) was collected at three time points: before treatment with nystatin, at the end of therapy and 2 months after finishing therapy. Activation of T cells and monocytes was assessed by flow cytometry. RESULTS The percentages of peripheral lymphocytes, T cells and their subpopulations, as well as monocytes were similar before, immediately following and two months after nystatin treatment. Cells expressing early activation marker CD69 and RANTES C-C chemokine receptor type 5 significantly increased immediately after treatment and returned to baseline levels after two months. Th17 cells, which have been implicated in the pathogenesis of DRS, remained unchanged. Central memory CD4+ subset and intermediate subset of monocytes were lower after therapy and this effect was sustained for two months. CONCLUSION Treatment of denture-related stomatitis does not seem to affect the general state of the cellular components of the immune system. The results suggest a potential proinflammatory effect of the antifungal agent, nystatin. Although transient and not intense, this effect might be of particular clinical importance, because of relationships between inflammation and certain diseases. Further studies are required to clarify this aspect.