Christian Stumpf

Differential effects of statins on relevant functions of human monocyte-derived dendritic cells

Statins were shown to possess immunomodulating properties, but the mechanisms of statin effects on the immune system are poorly understood. We analyzed the influence of statins on professional antigen‐presenting dendritic cells (DC). Immature DC were cultivated from monocytes of healthy donors. DC maturation was induced by lipopolysaccharide (LPS; 1 μg/mL). Unstimulated and LPS‐stimulated DC were treated with simvastatin or atorvastatin (0.1–1 μM). The expression of CD40, CD83, CD86, and human leukocyte antigen‐DR on unstimulated and LPS‐stimulated DC was reduced significantly by statins, and the expression of Toll‐like receptor 2 (TLR2) and TLR4 on LPS‐stimulated DC was enhanced temporarily. Statins caused a significant reduction of endocytosis of fluorescein isothiocyanate‐dextran by DC. Statins significantly inhibited the basal secretion of interleukin (IL)‐6, IL‐8, IL‐12, and tumor necrosis factor α from unstimulated DC, and their release from LPS‐stimulated DC was enhanced. In mixed leukocyte reaction, preincubation of LPS‐stimulated DC with statins significantly suppressed their clustering with T cells and their ability to induce T cell proliferation, CD71, and CD25 up‐regulation on T cells and the secretion of interferon‐γ and IL‐2 from T cells. In conclusion, this study showed that statins suppressed endocytosis, basal secretion of proinflammatory cytokines, and the ability of DC to induce T cell proliferation, activation, and T helper cell type 1 differentiation. However, statin preincubation of LPS‐stimulated DC caused a further increase in their secretion of proinflammatory cytokines.

Decrease of serum levels of the anti-inflammatory cytokine interleukin-10 in patients with advanced chronic heart failure

Inflammation plays a significant contributory role in the pathogenesis of chronic heart failure (CHF). Many studies have shown enhanced plasma levels of proinflammatory cytokines [i.e. tumour necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6] in patients with CHF. However, there are only few reports on the regulation of anti-inflammatory cytokines such as IL-10. IL-10 has potent deactivating properties in macrophages and T-cells and thus acts as a down-regulator of cell-mediated immune responses. The aim of the present study was to assess whether serum concentrations of IL-10 significantly differ between patients with CHF and healthy control subjects. Patients with CHF [ n =50; 66.9+/-12.6 years; mean ejection fraction, 22.1+/-9.2%; New York Heart Association (NYHA) class II-IV] and 25 healthy controls (63.6+/-10.2 years) were examined. Of the 50 patients with CHF, 32 patients were taking aspirin (100 mg/day) and 33 patients had lipid-lowering therapy with a statin. Serum IL-10 as well as TNF-alpha concentrations were measured using commercially available immunoassays. Patients with CHF showed significantly lower IL-10 concentrations (2.3+/-1.9 compared with 5.2+/-2.3 pg/ml; P <0.001). Patients with advanced CHF (NYHA class III and IV) had the lowest IL-10 plasma levels. Aspirin and statin therapy did not significantly influence serum levels of IL-10. The ratio of TNF-alpha to IL-10 was significantly higher in patients with advanced CHF (NYHA class III and IV, ratio 3.2+/-1.2 and 3.1+/-1.1 respectively, compared with control 0.4+/-0.2; P <0.01). Our present study demonstrates significantly decreased serum levels of IL-10 in patients with advanced CHF. Since IL-10 is known as a potent anti-inflammatory cytokine, its decrease in advanced CHF may favour the inflammatory milieu in CHF.

Enhanced levels of platelet P-selectin and circulating cytokines in young patients with mild arterial hypertension.

Background Emerging evidence links inflammation to atherosclerosis (AS). Although some studies have addressed the role of inflammation in patients with arterial hypertension (AH), its overall contribution in AH is far from being understood. Therefore, the present pilot study was designed to examine the role of platelet P-selectin and various inflammatory mediators in young patients with moderate AH without signs of target organ damage. Methods and results Fifteen patients with mild AH [33.8 ± 7.3 years, mean arterial pressure (MAP) 106.6 ± 10.4 mmHg] and 15 healthy normotensive controls (31.7 ± 10.6 years) were examined. Platelet P-selectin was analysed by flow cytometry. Plasma levels of monocyte-chemoattractant-protein-1 (MCP-1), high-sensitivity C-reactive protein (hsCRP), interleukin (IL)-6, tumour necrosis factor α (TNFα), and IL-10 levels were measured by enzyme immunoassay (EIA). Patients with mild AH showed significantly enhanced expression of platelet P-selectin [17.2 ± 5.4 versus 10.6 ± 4.2 mean fluorescence intensity (MFI), P < 0.001]. P-selectin expression positively correlated with MAP (r = 0.43, P < 0.05). Furthermore, patients with mild AH had significantly enhanced plasma levels of hsCRP (2.7 ± 3.8 versus 0.6 ± 0.9 mg/l, P < 0.01), IL-6 (1.4 ± 0.7 versus 0.6 ± 0.3 pg/ml, P < 0.001), TNFα (2.8 ± 0.7 versus 2.4 ± 0.4 pg/ml, P < 0.05), and MCP-1 (291.3 ± 100.7 versus 214.3 ± 8.3 pg/ml, P < 0.05). IL-6 levels positively correlated with hsCRP levels (r = 0.47, P < 0.05) and mean arterial pressure (MAP) (r = 0.44, P < 0.05). Conclusions This pilot study demonstrates that in an early stage of AH, inflammatory pathways are already activated. Besides pro-inflammatory cytokines, platelets seem to play a significant role in mediating inflammation in AH, which could lead to target organ injury. Further investigations have to clarify the role of early anti-inflammatory therapy, in patients with mild to moderate AH, in alleviating hypertensive target organ damage.

Enhanced levels of CD154 (CD40 ligand) on platelets in patients with chronic heart failure

Inflammation plays a significant contributory role in the pathogenesis of chronic heart failure (CHF). Previous data have shown enhanced plasma levels of proinflammatory cytokines, i.e. TNF‐α and IL‐6, as well as a persistent immune activation in patients with CHF. Furthermore, the immune modulator CD154 has been receiving increased attention, since it plays a key role in the pathophysiology of multicellular vascular events such as thrombosis, inflammation and atherosclerosis. Since CD154 intitiates and maintains the release of proinflammatory cytokines from endothelial cells, its potential role for the development and progression of CHF is of interest.

Delay of neutrophil apoptosis in acute coronary syndromes

Apoptosis of polymorphonuclear neutrophils (PMN) is currently discussed as a key event in the control of inflammation. This study determined PMN apoptosis and its underlying mechanisms in controls (C), patients with stable (SAP) or unstable angina (UAP), and with acute myocardial infarction (AMI). Blood was drawn from 15 subjects of each C, SAP, UAP, and AMI. Apoptosis was measured by flow cytometry in isolated PMN (propidium iodide staining) and PMN from whole blood (CD16, FcγRIII). Serum cytokines were determined by enzyme‐linked immunosorbent assay. Apoptosis of isolated PMN was delayed significantly in acute coronary syndromes (ACS) as compared with SAP or C (C, 51.2±12.6%; SAP, 44.9±13.6%; UAP, 28.4±10.1%; AMI, 20.3±8.5%; AMI or UAP vs. SAP or C, P<0.001). These results were confirmed by measurement of PMN apoptosis in cultured whole blood from patients and controls. Moreover, serum of patients with ACS markedly reduced apoptosis of PMN from healthy donors. Analysis of patients’ sera revealed significantly elevated concentrations of tumor necrosis factor α, interferon‐γ (IFN‐γ), granulocyte macrophage‐colony stimulating factor (GM‐CSF), and interleukin (IL)‐1β in ACS (vs. C and SAP). IFN‐γ, GM‐CSF, and IL‐1β significantly delayed PMN apoptosis in vitro. Furthermore, coincubation of PMN with adenosine 5′‐diphosphate‐activated platelets significantly inhibited PMN apoptosis as compared with coculture with unstimulated platelets. This study demonstrates a pronounced delay of PMN apoptosis in UAP and AMI, which may result from increased serum levels of IFN‐γ, GM‐CSF, and IL‐1β and from enhanced platelet activation. Therapeutical modulation of these determinants of PMN lifespan may provide a new concept for the control of inflammation in ACS.

Predictive value of the decrease in circulating dendritic cell precursors in stable coronary artery disease

DCs (dendritic cells) are present in atherosclerotic lesions leading to vascular inflammation, and the number of vascular DCs increases during atherosclerosis. Previously, we have shown that the levels of circulating DCPs (DC precursors) are reduced in acute coronary syndromes through vascular recruitment. In the present study, we have investigated whether DCP levels are also reduced in stable CAD (coronary artery disease). The levels of circulating mDCPs (myeloid DCPs), pDCPs (plasmacytoid DCPs) and tDCP (total DCPs) were investigated using flow cytometry in 290 patients with suspected stable CAD. A coronary angiogram was used to evaluate a CAD score for each patient as follows: (i) CAD excluded (n=57); (ii) early CAD (n=63); (iii) moderate CAD (n=85); and (iv) advanced CAD (n=85). Compared with controls, patients with advanced stable CAD had lower HDL (high-density lipoprotein)-cholesterol (P=0.03) and higher creatinine (P=0.003). In advanced CAD, a significant decrease in circulating mDCPs, pDCPs and tDCPs was observed (each P<0.001). A significant inverse correlation was observed between the CAD score and mDCPs, pDCPs or tDCPs (each P<0.001). Patients who required percutaneous coronary intervention or coronary artery bypass grafting had less circulating mDCPs, pDCPs and tDCPs than controls (each P<0.001). Multiple stepwise logistic regression analysis suggested mDCPs, pDCPs and tDCPs as independent predictors of CAD. In conclusion, we have shown that patients with stable CAD have significantly lower levels of circulating DCPs than healthy individuals. Their decrease appears to be an independent predictor of the presence of, and subsequent therapeutic procedure in, stable CAD.

Interleukin-10 improves left ventricular function in rats with heart failure subsequent to myocardial infarction.

Evidence has shown that pro‐inflammatory cytokines, especially TNF‐α, are involved in the inflammatory response in the remodelling process after myocardial infarction (MI). Although IL‐10, an anti‐inflammatory cytokine, has been shown to antagonize some of the deleterious effects of TNF‐α, little is known about its role in post‐MI left ventricular (LV) dysfunction. The aim of the present study was to investigate whether a therapy with rhIL‐10 could be beneficial in an animal model of post‐MI heart failure (HF).

Transient decrease in circulating dendritic cell precursors after acute stroke ? potential recruitment into the brain

The role of DCs (dendritic cells) as potent mediators of inflammation has not been sufficiently investigated in stroke. Therefore, in the present study, circulating mDCPs (myeloid DC precursors), pDCPs (plasmacytoid DCPs) and tDCPs (total DCPs) were analysed by flow cytometry in (i) healthy controls (n=29), (ii) patients with ACI-S (asymptomatic cerebral infarction stenosis; n=46), (iii) patients with TIA (transient ischaemic attack; n=39), (iv) patients with AIS (acute ischaemic stroke; n=73), and (v) patients with AHS (acute haemorrhagic stroke; n=31). The NIHSS (National Institutes of Health Stroke Scale) and infarction size on a CT (computer tomography) scan were evaluated after stroke. In a patient subgroup, post-mortem immunohistochemical brain analyses were performed to detect mDCs (CD209), pDCs (CD123), T-cells (CD3) and HLA-DR. In AIS and AHS, the numbers of circulating mDCPs (P<0.005), pDCPs (P<0.005) and tDCPs (P<0.001) were significantly reduced. A significant inverse correlation was found between the NIHSS and circulating DCPs (P<0.02), as well as between hsCRP (high-sensitivity C-reactive protein) and circulating DCPs (P<0.001). Patients with large stroke sizes on a CT scan had significantly lower numbers of mDCPs (P=0.007), pDCPs (P=0.05) and tDCPs (P=0.01) than those with smaller stroke sizes. Follow-up analysis showed a significant recovery of circulating DCPs in the first few days after stroke. In the infarcted brain, a dense infiltration of mDCs co-localized with T-cells, single pDCs and high HLA-DR expression were observed. In conclusion, acute stroke leads to a decrease in circulating DCPs. Potentially, circulating DCPs are recruited from the blood into the infarcted brain and probably trigger cerebral immune reactions there.

Enhanced platelet activation by prolactin in patients with ischemic stroke

Prolactin and leptin are newly recognised platelet co-stimulators due to potentiation of ADP-induced platelet aggregation. Elevated leptin levels have recently been found to be a risk factor for ischemic stroke in both men and women, and especially in combination with increased blood pressure for hemorrhagic stroke in men. Until now an association between hyperprolactinemia and ischemic stroke has not been investigated systematically. We determined plasma prolactin and leptin levels as well as platelet P-selectin expression in 36 patients with ischemic stroke or transient ischemic attack and detected a significant correlation between increased prolactin values and enhanced ADP stimulated P-selectin expression on platelets. In contrast, no correlation of leptin values with platelet P-selectin expression was found. Next we determined plasma prolactin and leptin as well as acquired and congenital risk factors of thrombophilia in patients with first-ever non-hemorrhagic stroke with or without atrial fibrillation. Excluding patients with such preexisting risk factors, 21 patients with and 59 patients without atrial fibrillation were identified. Patients without atrial fibrillation revealed significantly higher plasma prolactin levels than patients with atrial fibrillation. Furthermore, the influence of aspirin or clopidogrel on prolactin stimulated P-selectin expression in vitro was tested, showing that aspirin was without effect, whereas clopidogrel significantly inhibited platelet P-selectin expression. In conclusion, hyperprolactinemia might be a novel risk factor for stroke mediating its thrombogenic effect through enhanced platelet reactivity, and this might correspond to a higher efficacy of antiplatelet combination therapy with clopidogrel compared to aspirin therapy alone.

Atorvastatin enhances interleukin-10 levels and improves cardiac function in rats after acute myocardial infarction.

LV (left ventricular) remodelling is the basic mechanism of HF (heart failure) following MI (myocardial infarction). Although there is evidence that pro-inflammatory cytokines [including TNF-alpha (tumour necrosis factor-alpha) and IL-6 (interleukin-6)] are involved in the remodelling process, only little is known about the role of anti-inflammatory cytokines, such as IL-10. As accumulating evidence has revealed that statins possess anti-inflammatory properties, the aim of the present study was to elucidate the effect of atorvastatin on the modulation of the anti-inflammatory cytokine IL-10 and its effect on LV function in rats with HF subsequent to MI. Rats with MI, induced by permanent LAD (left anterior descending) branch coronary artery ligation, were treated for 4 weeks with atorvastatin (10 mg x kg(-1) of body weight x day(-1) via oral gavage) starting on the first day after induction of MI. Cardiac function was assessed by echocardiography and cardiac catheterization 4 weeks after MI induction. Membrane-bound and soluble fractions of TNF-alpha, IL-6 and IL-10 protein, the TNF-alpha/IL-10 ratio, serum levels of MCP-1 (monocyte chemoattractant protein-1) as well as myocardial macrophage infiltration were analysed. Treatment with atorvastatin significantly improved post-MI LV function (fractional shortening, +120%; dP/dt(max), +147%; and LV end-diastolic pressure, -27%). Furthermore atorvastatin treatment markedly decreased the levels of TNF-alpha, IL-6 and MCP-1, reduced myocardial infiltration of macrophages and significantly increased myocardial and serum levels of the anti-inflammatory cytokine IL-10. Thus the balance between pro-inflammatory and anti-inflammatory cytokines was shifted in the anti-inflammatory direction, as shown by a significantly decreased TNF-alpha/IL-10 ratio. Atorvastatin ameliorated early LV remodelling and improved LV function in rats with HF subsequent to MI. Our study suggests that the modulation of the balance between pro- and anti-inflammatory cytokines towards the anti-inflammatory cytokine IL-10 is one salutary mechanism underlying how atorvastatin influences post-MI remodelling and thus improves LV function.