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Background: Endothelial progenitor cells (EPC) promote angiogenesis and vascular repair. Though reduced EPC levels have been shown in rheumatoid arthritis, no study has so far evaluated EPCs in children with juvenile idiopathic arthritis (JIA). We aimed to study circulating EPCs in children with JIA, their relation to disease activity, and effects of anti TNF-α treatment. Methods: Circulating EPCs were quantified by flow cytometry based on CD34, CD133 and KDR expression in peripheral blood of 22 patients with oligoarticular JIA and 29 age-matched controls. EPCs were re-assessed in children with methotrexate-resistant oligo-extended JIA before and up to 12 month after initiation of anti-TNF-alpha therapy. Plasma concentrations of inflammatory and EPC-regulating factors were measured using a multiplex array. Confocal immunofluorescence was used to demonstrate EPCs in synovial tissues. Results: Children with active JIA showed a significant reduction of relative and absolute counts of circulating progenitor cells and EPCs compared to age-matched healthy controls. CD34+ cell levels were modestly and inversely correlated to disease activity. A strong inverse correlation was found between serum TNF-α and EPC levels. In 8 patients treated with anti TNF-α agents, the number of EPCs rose to values similar to healthy controls. CD34+KDR+ EPCs were found in the synovial tissue of JIA children, but not in control. Conclusions: Children with JIA have reduced levels of the vasculoprotective and proangiogenic EPCs. While EPCs may contribute to synovial tissue remodelling, EPC pauperization may indicate an excess cardiovascular risk if projected later in life. [ABSTRACT FROM AUTHOR]

There is a concern on the risk of thyroid cancer associated with glucagon-like peptide-1 (GLP-1) analogs including liraglutide and exenatide. In this article, we review related experimental studies, clinical trials and observational human studies currently available. In rodents, liraglutide activated the GLP-1 receptors on C-cells, causing an increased incidence of C-cell neoplasia. Animal experiments with monkeys demonstrated no increase in calcitonin release and no C-cell proliferation after long-term liraglutide administration. Longitudinal 2-year data from clinical trials do not support any significant risk for the activation or growth of C-cell cancer in humans in response to liraglutide. However, an analysis of the FDA adverse event reporting system database suggested an increased risk for thyroid cancer associated with exenatide after its marketing. Noticeably, a recent study discovered that GLP-1 receptor could also be expressed in human papillary thyroid carcinomas (PTC), but the impact of GLP-1 analogs on PTC is not known. Therefore, GLP-1 analogs might increase the risk of thyroid C-cell pathology in rodents, but its risk in humans awaits confirmation. Since GLP-1 receptor is also expressed in PTC besides C-cells, it is important to investigate the actions of GLP-1 on different subtypes of thyroid cancer in the future. [ABSTRACT FROM AUTHOR]

The beneficial effects of estrogens on the cardiovascular system are associated with adverse effects on reproductive tissues. On the basis of previous work indicating a major role for estrogen receptor (ER)-α in maintaining cardiovascular health, we evaluated the tissue selectivity of the ERα-selective agonist propyl pyrazole triol (PPT) compared with 17β-estradiol (E2) in vivo. Four weeks postovariectomy, equimolar doses of PPT and E2 were administered to rats in subcutaneous implants for 5 d. Both treatments restored rapid vasorelaxation of aortic tissue to estrogenic agents and prevented coronary hyperresponsiveness to angiotensin II in isolated heart preparations. Accordingly, multiple endpoints of myocardial ischemia-reperfusion injury exacerbated by ovariectomy returned to baseline following treatment. These protective effects were linked to increased in vivo levels of endothelial progenitor cells (EPCs). Human EPC function was enhanced in vitro after PPT treatment. In sharp contrast to E2, PPT treatment had no effect on uterine weight and histomorphology except for vessel density, and failed to up-regulate classic estrogen target genes. Dissection of the effects on vascular reactivity and uterine morphology was also observed following increased exposure to PPT at a higher dose for longer time. These data provide the first in vivo evidence for tissue-specific ERα activation. By conferring cardiovascular protection dissected from unwanted uterotrophic effects, ERα-selective agonists may represent a potential safer alternative to natural hormones. [ABSTRACT FROM AUTHOR]

EPCs (endothelial progenitor cells) exert vasculoprotective effects and can be used for regenerative therapies. However, several isolation protocols have been described, with inconsistent results. Statins are among the most effective compounds that stimulate EPC numbers in vivo and ex vivo. We aim to describe the effects of rosuvastatin on different subtypes of putative EPCs. EPCs were cultured from mononuclear cells of blood donors and isolated according to three protocols: CFU-EC (colony forming units-endothelial cells), early (or 'monocytic') EPCs and late outgrown EPCs. Rosuvastatin (0.1-100 nM) was added at the beginning of culture (T0) or after the initial adhesion step (T1). Polarization of monocytic EPCs was assessed as expression of proinflammatory M1 markers (CD68 and CCR2) or anti-inflammatory M2 markers (CX3CR1, CD163, CD206). We found that 1 nM rosuvastatin increased the number of CFU-EC and late EPCs by about 3-fold, while lower concentrations had no significant effects. Rosuvastatin (0.1 nM) increased AcLDL+Lectin+ early EPCs by about 60%, while higher concentrations exerted inhibitory effects on early EPCs. Addition of rosuvastatin at T0 was more effective in stimulating CFU-EC and early EPCs, while addition at T1 was more effective in stimulating late EPCs. Rosuvastatin had no effects on proliferation rate of CFU-EC, early EPCs and late EPCs. We also found that 0.1 nM rosuvastatin reduced the M1/M2 ratio in early EPCs, which retain monocytic features. In conclusion, we show that rosuvastatin had significant stimulatory effects on EPCs irrespective of the culture protocol. Rosuvastatin also induced anti-inflammatory polarization of monocytic EPCs. [ABSTRACT FROM AUTHOR]

Abstract: Aim: To evaluate the impact of endothelial progenitor cells (EPCs), a subset of committed circulatory stem cells, on the development of bronchopulmonary dysplasia (BPD) and other short term outcomes in a cohort of extremely premature newborns. Methods: Progenitor cells were quantified by flow cytometry at birth in 36 neonates born <=28weeks of gestation and at 36 postmenstrual weeks in 18 of them. Cells expressing the stemness markers CD34, CD133, or both were defined as circulating progenitor cells (CPCs). EPCs were defined as CPCs co-expressing the endothelial marker KDR. Results: Mean (SD) gestational age and birth weight of the infants studied were 26.2(1.5) weeks and 761.6(171.8) grams, respectively. EPC levels at birth did not differ between infants who subsequently developed BPD (n=9) and those who did not (n=24) [CD34+KDR+ EPCs: 81(34–41) vs 80(56–110), p=0.7] and were not correlated with the duration of mechanical ventilation or O2-dependence, nor with the need of surfactant replacement. Infants with a hemodynamically significant patent ductus arteriosus (PDA) (n=22) had significantly lower EPC levels at birth than those with no PDA (n=11) [CD34+KDR+ cells: 47(34–92) vs 142(84.5–221), p=0.008]. Data from the 18 infants studied both at birth and at 36 postmenstrual weeks showed that, while CPCs sharply decline over time, levels of all EPCs phenotypes are preserved after delivery. Conclusions: Levels of EPCs at birth did not affect the risk of developing BPD in our group of extremely premature neonates. However, the association between low EPC counts at birth and PDA may be clinically relevant, and deserves further studies. [Copyright &y& Elsevier]

STAT3 mutations have been described in 30-40% of T-large granular lymphocyte (T-LGL) leukemia patients, leading to STAT3 pathway activation. Considering the heterogeneity of the disease and the several immunophenotypes that LGL clone may express, the aim of this work was to evaluate whether STAT3 mutations might be associated with a distinctive LGL immunophenotype and/or might be indicative for specific clinical features. Our series of cases included a pilot cohort of 101 T-LGL leukemia patients (68 CD8+/CD4- and 33 CD4+/CD8±) from Padua Hematology Unit (Italy) and a validation cohort of additional 20 patients from Rennes Hematology Unit (France). Our results indicate that i) CD8+ T-LGL leukemia patients with CD16+/CD56- immunophenotype identify a subset of patients characterized by the presence of STAT3 mutations and neutropenia, ii) CD4+/CD8± T-LGL leukemia are devoid of STAT3 mutations but characterized by STAT5b mutations, and iii) a correlation exists between STAT3 activation and presence of Fas ligand, this molecule resulting highly expressed in CD8+/CD16+/CD56- patients. Experiments with stimulation and inhibition of STAT3 phosphorylation confirmed this relationship. In conclusion, our data show that T-LGL leukemia with specific molecular and phenotypic patterns is associated with discrete clinical features contributing to get insights into molecular bases accounting for the development of Fas ligand-mediated neutropenia., Competing Interests: CONFLICTS OF INTEREST The authors declare no competing financial interests.

Most patients affected by chronic lymphocytic leukemia are diagnosed by flow cytometry. Several immunophenotypic markers have been identified as significant and independent prognostic variables, especially from retrospective cohorts. However, while attractive because their detection is inexpensive and feasible in most laboratories, only few have been validated by independent series. The expression of leukocyte-associated immunoglobulin-like receptor-1 (also known as LAIR1, LAIR-1 or CD305), an inhibitor of B-cell receptor-mediated signaling, has been reported to be lacking in high-risk chronic lymphocytic leukemia. However, its correlation with biological variables and its prognostic significance remain unknown. We investigated 311 consecutive patients, prospectively enrolled since 2007. Methods for studying patients were standardized and included clinical assessment, immunophenotype, fluorescence in situ hybridization, and status of immunoglobulin heavy chain variable region genes. Overall, 22.1% of patients had Binet stage B or C disease, 38.5% had unmutated immunoglobulin genes, 15.1% had high-risk cytogenetic abnormalities, 23.4% were CD38(+), 37.8% CD49d(+), and 59.8% LAIR1(+). Expression of LAIR1 was inversely related to that of CD38 (P=0.0005), but was not associated with CD49d expression (P=0.96). A significantly lower expression of LAIR1 was observed in patients with Binet stage B or C disease (P=0.023), and in the presence of high-risk cytogenetic abnormalities (P=0.048) or unmutated immunoglobulin heavy chain variable region genes (P<0.0001). At univariate analysis LAIR1(+) was significantly associated with longer time to first treatment (P=0.0002). This favorable effect of LAIR1(+) was confirmed by multivariate analysis (hazard ratio=2.1, P=0.03 for LAIR1). Our results indicate that LAIR1 expression is a reliable and inexpensive marker capable of independently predicting time to first treatment in newly diagnosed unselected patients with chronic lymphocytic leukemia.

Diabetes mellitus (DM) alters circulating progenitor cells relevant for the pathophysiology of coronary artery disease (CAD). While endothelial progenitor cells (EPCs) are reduced, there is no data on procalcific polarization of circulating progenitors, which may contribute to vascular calcification in these patients. In a cohort of 107 subjects with and without DM and CAD, we analyzed the pro-calcific versus endothelial differentiation status of circulating CD34+ progenitor cells. Endothelial commitment was determined by expression of VEGFR-2 (KDR) and pro-calcific polarization by expression of osteocalcin (OC) and bone alkaline phosphatase (BAP). We found that DM patients had significantly higher expression of OC and BAP on circulating CD34+ cells than control subjects, especially in the presence of CAD. In patients with DM and CAD, the ratio of OC/KDR, BAP/KDR, and OC+BAP/KDR was about 3-fold increased than in other groups. EPCs cultured from DM patients with CAD occasionally formed structures highly suggestive of calcified nodules, and the expression of osteogenic markers by EPCs from control subjects was significantly increased in response to the toll-like receptor agonist LPS. In conclusion, circulating progenitor cells of diabetic patients show a phenotypic drift toward a pro-calcific phenotype that may be driven by inflammatory signals.

The beneficial or detrimental effects of androgens on the cardiovascular system are debated. Endothelial progenitor cells are bone-marrow-derived cells involved in endothelial healing and angiogenesis, which promote cardiovascular health. Oestrogens are potent stimulators of endothelial progenitor cells, and previous findings have indicated that androgens may improve the biology of these cells as well. In the present study, we show that testosterone and its active metabolite dihydrotestosterone exert no effects on the expansion and function of late endothelial progenitors isolated from the peripheral blood of healthy human adult males, whereas they positively modulate early 'monocytic' endothelial progenitor cells. In parallel, we show that castration in rats is followed by a decrease in circulating endothelial progenitor cells, but that testosterone and dihydrotestosterone replacement fails to restore endothelial progenitor cells towards normal levels. This is associated with persistently low oestrogen levels after androgen replacement in castrated rats. In a sample of 62 healthy middle-aged men, we show that circulating endothelial progenitor cell levels are more directly associated with oestradiol, rather than with testosterone, concentrations. In conclusion, our results collectively demonstrate that androgens exert no direct effects on endothelial progenitor cell biology in vitro and in vivo.

Bone marrow-derived progenitor cells are involved in the homeostasis of the cardiovascular system through differentiation into endothelium, smooth muscle, and cardiomyocytes. Alterations of these extremely plastic cells have been recognized as both markers of cardiovascular risk and pathophysiological links between risk factors and development of atherosclerosis. Metabolic syndrome, as a cluster of well-defined cardiovascular risk factors, represents a strong predictor of cardiovascular events and death. Moreover, components of the syndrome interact with one another and synergistically increase this risk. Here we describe all metabolic syndrome components as being characterized by alterations in circulating progenitor cells, especially endothelial cells. We also highlight how endothelial progenitors may mediate the interactions between cardiometabolic risk factors in a complex interplay and discuss potential implications for prevention and therapy.

We have shown previously that the chemokine receptors CXCR3 and CXCR6 are coexpressed by Th1 cells infiltrating the lung and the granuloma of patients with sarcoidosis. In this study, we evaluated the role of CCL20/CCR6 interaction in the pathogenesis of acute and chronic pulmonary sarcoidosis. By flow cytometry and molecular analyses, we have demonstrated that Th1 cells isolated from the bronchoalveolar lavage (BAL) of patients with sarcoidosis and T cell alveolitis are equipped with CCR6. Furthermore, CCR6(+) T cells coexpressed the chemokine receptors CXCR3 and CXCR6. Immunohistochemical analysis of lung specimens has shown that CCR6(+) T cells infiltrate lung interstitium and surround the central core of the granuloma. It is interesting that CCR6 was never detected on the alveolar macrophage (AM) surface, and it is observed in the cytoplasm of AMs from patients with sarcoidosis and alveolitis. The CCR6 ligand CCL20 was expressed by macrophages, multinucleated giant cells, and epithelioid cells infiltrating the granuloma. Furthermore, detectable levels of CCL20 protein are seen in the BAL fluid components of patients with active sarcoidosis, and sarcoid AMs release the CCR6 ligand in vitro. From a functional point of view, sarcoid Th1 cells were able to respond to CXCL10, CXCL16, and CCL20 in migratory assays. In vitro kinetic studies demonstrated that CCR6 is induced rapidly by IL-2, IL-18, and IFN-gamma. In conclusion, T cells expressing CCR6, CXCR3, and CXCR6 act coordinately with respective ligands and Th1 inflammatory cytokines in the alveolitic/granuloma phases of the disease.