Detection of Angiogenic T Cells and Endothelial Progenitor Cells in Behçet Disease and Determination of Their Relationship with Disease Activity

Angiogenic T (Tang) cells and endothelial progenitor cells (EPCs) play a role in maintaining vascular integrity and repair. This study considers the association between them and Behçet disease (BD) and disease activity. Fifty patients with BD and forty-five age- and gender-matched healthy controls were included in the study. The participants' demographic, clinical, and laboratory characteristics were recorded, and their blood Tang cell and EPC counts were determined. Fifty patients were diagnosed with BD, consisting of 24 females and 26 males. The blood Tang cell (3.5 ± 1.2 cells/μL in patients, 4 ± 0.9 cells/μL in controls, p = 0.046)) and EPC (2.9 ± 0.9 cells/μL in patients, 3.7 ± 1 cells/μL in controls, p = 0.001) counts were significantly lower for the patient group with BD than for the control group. The blood Tang cell (42.5 ± 4.9% in active patients, 48.9 ± 7.9% in inactive patients, p = 0.001) and EPC (35.5 ± 6.4% in active patients, 41.2 ± 6.3% in inactive patients, p = 0.004) levels were lower for the patient group with active BD than for the inactive patient group. A weak positive correlation was present between the blood Tang cell and EPC percentage values in BD (r: 0.318, p = 0.002). It was determined that Tang cell and EPC counts are lower in BD, and these reductions become more profound with increasing disease activity. This situation may prevent the development of a sufficient immune response against a disease with a course of chronic inflammation or may trigger the formation of autoreactive immunity. A reduction in Tang cells and EPCs may serve as a marker or predictor of vascular damage in BD patients and represents the progression of vascular injury.

The IMMENSE Study: The Interplay Between iMMune and ENdothelial Cells in Mediating Cardiovascular Risk in Systemic Lupus Erythematosus

Patients with systemic lupus erythematosus (SLE) have a significant increase in cardiovascular (CV) risk although they display a preserved number of circulating angiogenic CD3⁺CD31⁺CXCR4⁺ T cells (T_ang), a subpopulation of T cells which promotes repair of damaged endothelium. This happens due to the concomitant expansion of a T_ang subset with immunosenescent features, such as the loss of CD28. Therefore, the aim of this study was to elucidate the interplay between T_ang subpopulations and endothelial cells in a group of young SLE patients without previous cardiovascular events. Twenty SLE female patients and 10 healthy controls (HCs) were recruited. Flow cytometric analysis of endothelial progenitor cells (EPCs) and T_ang subsets were performed and serum levels of interleukin (IL)-6, -8, matrix metalloproteinase (MMP)-9 and interferon (IFN)-γ were measured. Human umbilical vein endothelial cells (HUVECs) proliferation and pro-inflammatory phenotype in response to subjects’ serum stimulation were also evaluated. Results showed that the percentage of T_ang and EPC subsets was reduced in SLE patients compared with HCs, with a marked increase of senescent CD28^null cells among T_ang subset. SLE disease activity index-2000 (SLEDAI-2K) was inversed related to T_ang cells percentage. Furthermore, IL-8 serum levels were directly correlated with the percentage of T_ang and inversely related to the CD28^null T_ang subsets. We indirectly evaluated the role of the T_ang subset on the endothelium upon stimulation with serum from subjects with a low percentage of T_ang CD3⁺ cells in HUVECs. HUVECs displayed pro-inflammatory phenotype with up-regulation of mRNA for IL-6, intercellular adhesion molecule (ICAM)-1 and endothelial leukocyte adhesion molecule (ELAM)-1. Cell proliferation rate was directly related to IL-8 serum levels and EPC percentage. In highly selected young SLE patients without previous CV events, we found that the deterioration of T_ang compartment is an early event in disease course, preceding the development of an overt cardiovascular disease and potentially mediated by SLE-specific mechanisms. The overcome of the CD28^null subset exerts detrimental role over the T_ang phenotype, where T_ang could exert an anti-inflammatory effect on endothelial cells and might orchestrate via IL-8 the function of EPCs, ultimately modulating endothelial proliferation rate.

Low-density granulocytes and monocytes as biomarkers of cardiovascular risk in systemic lupus erythematosus

OBJECTIVE

The aim was to evaluate the most relevant cell populations involved in vascular homeostasis as potential biomarkers of SLE-related cardiovascular disease (CVD).

METHODS

Low-density granulocytes (LDGs), monocyte subsets, endothelial progenitor cells, angiogenic T (Tang) cells, CD4+CD28null and Th1/Th17 lymphocytes and serum cytokine levels were quantified in 109 SLE patients and 33 controls in relationship to the presence of subclinical carotid atheromatosis or cardiovascular disease. A second cohort including 31 recent-onset SLE patients was also included.

RESULTS

Raised monocyte and LDG counts, particularly those LDGs negative for CD16/CD14 expression (nLDGs), in addition to the ratios of monocytes and nLDGs to high-density lipoprotein-cholesterol (HDLc) molecules (MHR and nLHR, respectively), were present in SLE patients with traditional risk factors or subclinical atheromatosis but not in those who were CV-free, thus revealing their value in the identification of patients at risk of CVD, even at the onset of disease. Accordingly, nLDGs were correlated positively with carotid intima-media thickness (cIMT) and with inflammatory markers (CRP and IL-6). A bias towards more differentiated monocyte subsets, related to increased IFN-α and IL-17 serum levels, was also observed in patients. Intermediate monocytes were especially expanded, but independently of their involvement in CVD. Finally, CD4+CD28null, Th17 and Th1 lymphocytes were increased, with CD4+CD28null and Th17 cells being associated with cIMT, whereas endothelial progenitor and Tang cell levels were reduced in all SLE patients.

CONCLUSION

The present study highlights the potential use of MHR and nLHR as valuable biomarkers of CVD risk in SLE patients, even at diagnosis. The increased amounts of nLDGs, monocytes, Th17 and senescent-CD28null subsets, coupled with reduced pro-angiogenic endothelial progenitor cells and Tang cells, could underlie the development of atheromatosis in SLE.

Angiogenic T cells are decreased in people with type 2 diabetes mellitus and recruited by the dipeptidyl peptidase-4 inhibitor Linagliptin: A subanalysis from a randomized, placebo-controlled trial (RELEASE study)

Angiogenic T (Tang) cells are mediators of vascular repair, and are characterized by surface expression of CXCR4. This receptor for stromal cell-derived factor-1α (SDF-1α) is cleaved by dipeptidyl peptidase-4 (DPP-4). Tang cell levels were investigated in people with type 2 diabetes mellitus (T2DM) compared with matched healthy controls and after treatment with the DPP-4 inhibitor Linagliptin. People with T2DM were randomized to 5 mg/day Linagliptin (n = 20) or placebo (n = 21) for 26 weeks. Tang cell frequency was identified in peripheral blood mononuclear cells (CD3⁺ CD31⁺ CXCR4⁺ ) and levels of endothelial progenitor cells (EPCs) (CD34⁺ CD133⁺ KDR⁺ ) were also assessed in whole blood. Circulating Tang cell levels were significantly lower in people with T2DM compared with the healthy control group. SDF-1α levels increased significantly in Linagliptin-treated people with T2DM compared to placebo, and a trend was observed in change of Tang cell levels, while EPC count did not change. In conclusion, circulating Tang cell levels were considerably lower in people with T2DM, while a trend was observed in recruitment of Tang cells after 26 weeks of treatment with Linagliptin. These data suggest that DPP-4 inhibitors may potentially exert beneficial effects on bone marrow-driven vascular repair.

Systemic Lupus Erythematosus and Endothelial Dysfunction: A Close Relationship

BACKGROUND

Accelerated atherosclerosis, responsible for premature cardiovascular disease, has been estimated to develop or progress in 10% of systemic lupus erythematosus (SLE) patients each year and to be 6-fold more frequent in SLE compared with the general population. The mechanisms underlying accelerated atherosclerosis in SLE are complex and involve classical and "non-classical" cardiovascular risk factors. Subclinical and disseminated atherosclerosis is associated with endothelial dysfunction and arterial stiffness.

OBJECTIVE

The aim of this review is to analyze the association between SLE and endothelial dysfunction.

RESULTS AND CONCLUSION

Different mechanisms have been proposed to explain the prevalence of endothelial dysfunction in SLE, which are briefly reported in this review: impaired clearance of apoptotic cells, oxidative stress markers, B cell activation with different circulating autoantibodies, different subtypes of T lymphocytes, cytokine cascade. Several studies and meta-analyses show a significant trend towards a prevalence of subclinical accelerated atherosclerosis in patients with SLE compared with healthy controls, since childhood. Based on general considerations, we suggest a multidisciplinary management to assess endothelial dysfunction at the diagnosis of the disease and to periodically search for and treat the traditional cardiovascular risk factors. Prospective studies are needed to confirm the benefits of this management.