Functional implications of IgG anti-endothelial cell antibodies in pulmonary arterial hypertension.

The objective of this study was to research the functionality of anti-endothelial cell antibodies (AECA) in pulmonary arterial hypertension (PAH) by assessing the effects of IgG from AECA-positive PAH patients on the induction of adhesion molecules on human umbilical vein endothelial cells (HUVECs) and on the production of pro-inflammatory cytokines and chemokines by HUVECs. To achieve this purified IgG from 28 PAH patients were included. IgG from systemic sclerosis (SSc) (n = 58) and systemic lupus erythematosus (SLE) (n = 16) patients without PAH were included as disease controls. Intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin expression on HUVECs, incubated with patient IgG, were quantified by flow cytometry. Production of interleukin (IL)-1ß, -6, -8, and CC chemokine ligand 2 (CCL2) by HUVECs, incubated with patient IgG, were quantified by multiplex flow cytometry. Our results showed that IgG from AECA-positive PAH, SSc and SLE patients induced significantly higher expression of ICAM-1, VCAM-1, and E-selectin and production of IL-6, -8, and CCL2 compared to IgG from AECA-negative patients and IgG from healthy controls. Like in SLE and SSc, IgG from AECA-positive PAH patients can activate endothelial cells to a pro-adhesive and pro-inflammatory state. Therefore, IgG AECA could play a pathogenic role by inducing inflammatory injury of vascular endothelium which is considered a key player in the initiation and progression of PAH.

Angiogenic T-cells and putative endothelial progenitor cells in hypertension-related cerebral small vessel disease.

BACKGROUND AND PURPOSE: Cerebral small vessel disease (CSVD) may be caused by endothelial dysfunction, whereas endothelial progenitor cells (EPC) may attenuate endothelial dysfunction. Their vitality is lower in CSVD. A subset of lymphocytes, angiogenic T-cells, is capable to stimulate EPC function. The purpose of our study was to explore the relation between CSVD manifestations, angiogenic T-cells, and EPC in hypertensive patients with CSVD. METHODS: We compared 32 essential hypertensive patients with CSVD (white matter lesions, asymptomatic lacunar infarcts, or microbleeds on 1.5-Tesla MRI) to 29 age-matched and sex-matched hypertensive controls. We counted angiogenic T-cells (CD3(+)/CD31(+)/CD184(+)) and putative EPC (CD31(+)/CD34(+)/CD45(-)/KDR(+)) by flow cytometry and determined EPC vitality by in vitro cluster formation. RESULTS: Putative EPC numbers were lower in hypertensive individuals with CSVD than in those without (10±7(.)10(3)/mL versus 13±6(.)10(3)/mL [median±interquartile range]; P=0.011). Angiogenic T-cell numbers were also lower in hypertensive individuals with CSVD than in those without (0.56±0.25(.)10(9)/mL versus 0.78±0.50(.)10(9)/mL; P=0.008). Higher angiogenic T-cell numbers independently related to absence of CSVD (odds ratio, 0.088; 95% confidence interval, 0.012-0.627). CONCLUSIONS: Our data suggest that angiogenic T-cells and putative EPC independently relate to radiological CSVD manifestations in hypertensive patients.