Secretory leukocyte proteinase inhibitor-competent DNA deposits are potent stimulators of plasmacytoid dendritic cells: implication for psoriasis.

Secretory leukocyte proteinase inhibitor (SLPI) is a well-established inhibitor of serine proteases such as human neutrophil elastase (HNE) and a NF-κB regulatory agent in immune cells. In this paper, we report that SLPI plays a previously uncharacterized role in regulating activation of plasmacytoid dendritic cells (pDCs). As the main source of IFN type I (IFNI), pDCs are crucial contributors to inflammatory and likely wound-healing responses associated with psoriasis. The mechanisms responsible for activation of pDCs in psoriatic skin are therefore of substantial interest. We demonstrate that in lesional skin of psoriasis patients, SLPI together with its enzymatic target HNE and DNA, is a component of neutrophil extracellular traps (NETs). Whereas SLPI(+) neutrophils and NETs were found to colocalize with pDCs in psoriatic skin, a mixture of SLPI with neutrophil DNA and HNE induced a marked production of IFNI by pDCs. IFNI synthesis by stimulated pDCs was dependent on intracellular DNA receptor TLR9. Thus, SLPI may contribute to psoriasis by enabling pDCs to sense extracellular DNA and produce IFNI.

Synergistic effects of asymmetrical dimethyl-L-arginine accumulation and endothelial progenitor cell deficiency on renal function decline during a 2-year follow-up in stable angina.

BACKGROUND: Renal insufficiency predisposes to coronary artery disease (CAD), but also CAD and traditional risk factors accelerate renal function loss. Endothelial progenitor cell (EPC) deficiency and elevated asymmetrical dimethyl-L-arginine (ADMA), an endogenous nitric oxide (NO) formation inhibitor, predict adverse CAD outcome. Our aim was to assess changes in estimated glomerular filtration rate over time (DeltaeGFR) in relation to baseline EPC blood counts and ADMA levels in stable angina. METHODS: Eighty non-diabetic men with stable angina were followed up for 2 years after elective coronary angioplasty. Exclusion criteria included heart failure, left ventricular systolic dysfunction, eGFR <30 ml/min/1.73 m(2) and coexistent diseases. Those with cardiovascular events or ejection fraction <55% during the follow-up were also excluded. A baseline blood count of CD34+/kinase-insert domain receptor (KDR)+ cells, a leukocyte subpopulation enriched for EPC, was quantified by flow cytometry (percentage of lymphocytes). RESULTS: A synergistic interaction (P = 0.015) between decreased CD34+/KDR+ cell counts and increased plasma ADMA, but not symmetrical dimethyl-L-arginine, was the sole significant multivariate DeltaeGFR predictor irrespective of baseline eGFR. DeltaeGFR was depressed in the simultaneous presence of high ADMA (>0.45 micromol/l, median) and low CD34+/KDR+ cell counts (<0.035%, median) compared to either of the other subgroups (P = 0.001-0.01). DeltaeGFR did not correlate with traditional risk factors, angiographic CAD extent, levels of C-reactive protein and soluble vascular cell adhesion molecule-1. CONCLUSIONS: Elevated ADMA and EPC deficiency may synergistically contribute to accelerated renal function decline in stable angina. This could result from the impairment of the EPC-dependent endothelial renewal in the kidney, an NO-dependent process.

Interaction of human peripheral blood monocytes with apoptotic polymorphonuclear cells.

Macrophages have the potential to recognize apoptotic neutrophils and phagocytose them while the same function for monocytes is uncertain. In fact, early findings indicated that monocytes started to phagocytose neutrophils on the third day of differentiation to macrophages. Here we show, using flow cytometry and confocal microscopy, that peripheral blood monocytes phagocytose apoptotic but not freshly isolated granulocytes. Recognition of apoptotic cells is predominantly connected with CD16(+) monocytes (CD14(high) CD16(+) and CD14(dim) CD16(+)) and requires CD36. Clearance of apoptotic polymorphonuclear leucocytes appears to be independent of the CD14 mechanism. Uptake of apoptotic Jurkat T cells by monocytes is CD14 and CD36 dependent. Liposomes containing phosphatidyl-l-serine reduce binding of apoptotic polymorphonuclear leucocytes. Lipopolysaccharide-activated subpopulations of monocytes while in contact with apoptotic cells produce more anti-inflammatory cytokine interleukin-10 whereas the production of pro-inflammatory cytokines, tumour necrosis factor-alpha and interleukin-1beta is reduced.

Association between endothelial progenitor cell depletion in blood and mild-to-moderate renal insufficiency in stable angina.

BACKGROUND: Low blood counts of CD34/kinase-insert domain receptor double-positive cells (CD34(+)/KDR(+) cells)-a leukocytes subpopulation enriched for bone marrow-derived endothelial progenitor cells (EPC)- predict adverse outcomes in coronary artery disease (CAD). The dependence of EPC numbers on the glomerular filtration rate (GFR), another prognostic factor, has not been reported in CAD yet. Our aim was to assess CD34(+)/KDR(+) cell counts versus GFR in stable angina. METHODS: We studied 102 stable angina men with severe angiographic CAD and normal left-ventricular systolic function. CD34(+)/KDR(+) cells were enumerated by flow cytometry. RESULTS: With lowering GFR, CD34(+)/KDR(+) cell numbers (% of lymphocytes, median and interquartile range) decreased: 0.04 (0.03-0.06), 0.03 (0.02-0.05) and 0.02 (0.01-0.03)% for GFR >or=90, 60-89 and 30-59 ml/min/1.73 m(2), respectively (P < 0.001 for trend). CD34(+)/KDR(+) cell counts correlated with GFR (r = 0.25, P = 0.01), CAD extension score (r = -0.20, P = 0.04), soluble form of vascular cell adhesion molecule-1 (sVCAM-1) (r = -0.22, P = 0.03) and homocysteine (r = -0.20, P = 0.04) levels. A GFR <90 ml/min/1.73 m(2) was associated with insignificantly higher plasma erythropoietin concentrations (r = -0.22, P = 0.09 for trend) that correlated with haemoglobin levels (r = -0.33, P = 0.01, n = 59). The GFR-CD34(+)/KDR(+) cells relation was attenuated, yet maintained (beta = 0.19 +/- 0.09, P = 0.04) on adjustment for the remaining multivariate determinants of CD34(+)/KDR(+) cell numbers: sVCAM-1 (beta = -0.20 +/- 0.09, P = 0.03) and haemoglobin (beta = 0.18 +/- 0.09, P = 0.05). CONCLUSIONS: Mild-to-moderate renal dysfunction accompanying stable angina is associated with CD34(+)/KDR(+) cell depletion, which partially depends on concomitant endothelial dysfunction and a tendency to anaemia (despite insignificantly higher erythropoietin) irrespective of an angiographic CAD extent. This may exacerbate an imbalance between endothelial injury and EPC-mediated repair, thus contributing to high cardiovascular risk in CAD coexisting with renal insufficiency.

Coincidence of moderately elevated N-terminal pro-B-type natriuretic peptide, endothelial progenitor cells deficiency and propensity to exercise-induced myocardial ischemia in stable angina.

AIM: To assess endothelial progenitor cells (EPC) counts, a novel prognostic marker, in relation to classical adverse outcome predictors - N-terminal pro-B-type natriuretic peptide (NT-proBNP), impaired left ventricular (LV) relaxation and exercise-induced ischemia - in stable coronary artery disease (CAD) with preserved LV systolic function. METHODS: We studied 30 non-diabetic men with one-vessel CAD, LV ejection fraction 60% and normal LV diastolic function (n=16) or impaired LV relaxation (by ultrasound including tissue Doppler) (n=14), and 14 non-CAD controls matched for risk profile and medication. CD34+/kinase-insert domain receptor (KDR)+ cells (CD34+/KDR+ cells), a leukocytes subpopulation enriched for EPC, were enumerated by flow cytometry. RESULTS: CAD patients with abnormal LV relaxation exhibited significantly elevated NT-proBNP and decreased CD34+/KDR+ cells vs. CAD with regular diastolic function and non-CAD controls. An inverse NT-proBNP-CD34+/KDR+ cells relationship was precipitated by the clustering of high resting NT-proBNP and low CD34+/KDR+ cells in the subjects with a lower Duke treadmill score. CONCLUSIONS: Propensity to symptomatic exertional ischemia may underlie the coincidence of moderately elevated NT-proBNP and EPC deficiency in stable angina. Additionally, chronic subclinical ischemia can also be involved in these associations. These might result from BNP overexpression in the ischemic myocardium and a hypothetical exhaustion of the bone marrow capacity to mobilize EPC at multiple ischemic episodes, thus contributing to NT-proBNP prognostic effect irrespective of hemodynamic factors.

Elevated plasma asymmetric dimethyl-L-arginine levels are linked to endothelial progenitor cell depletion and carotid atherosclerosis in rheumatoid arthritis.

OBJECTIVE: Similarities between rheumatoid arthritis (RA) and atherosclerosis include endothelial dysfunction (an antecedent of plaque formation) and depletion of circulating bone marrow-derived endothelial progenitor cells. This study was undertaken to test the hypothesis that endothelial progenitor cell depletion and subclinical atherosclerosis in RA may be related to accumulation of an endogenous inhibitor of nitric oxide (NO) synthesis, asymmetric dimethyl-L-arginine. METHODS: We studied 30 patients with active RA and 20 age- and sex-matched healthy controls. Exclusion criteria were clinically evident atherosclerosis, traditional risk factors, hyperhomocysteinemia, and renal dysfunction. The blood endothelial progenitor cell count was assayed by flow cytometry and expressed as a percentage of lymphocytes. Plasma L-arginine, asymmetric dimethyl-L-arginine, and symmetric dimethyl-L-arginine were measured with liquid chromatography-mass spectrometry. Mean carotid intima-media thickness (IMT) was assessed by B-mode ultrasound. RESULTS: In RA patients, we found elevated levels of asymmetric dimethyl-L-arginine (mean +/- SD 0.49 +/- 0.07 micromoles/liter versus 0.40 +/- 0.07 micromoles/liter in controls; P < 0.001), a depressed endothelial progenitor cell count (0.039 +/- 0.025% versus 0.063 +/- 0.035%; P < 0.05), and increased IMT (0.65 +/- 0.13 mm versus 0.55 +/- 0.10 mm; P < 0.01), with no differences in levels of L-arginine or symmetric dimethyl-L-arginine. The endothelial progenitor cell count was inversely correlated with the level of asymmetric dimethyl-L-arginine. IMT was positively related to the ratio of asymmetric dimethyl-L-arginine to L-arginine and negatively related to the endothelial progenitor cell count, in univariate and multivariate analyses. CONCLUSION: Plasma asymmetric dimethyl-L-arginine levels are elevated in RA patients free of cardiovascular disease or risk factors. Asymmetric dimethyl-L-arginine accumulation may contribute to endothelial progenitor cell depletion via depressed NO-dependent endothelial progenitor cell mobilization and/or survival, with consequent impairment of endothelial progenitor cell-mediated endothelial repair, which can promote atherogenesis in RA.