Studies completed to date provide persuasive evidence that placental cell-derived exosomes play a significant role in intercellular communication pathways that potentially contribute to placentation and development of materno-fetal vascular circulation. The aim of this study was to establish the gestational-age release profile and bioactivity of placental cell-derived exosome in maternal plasma. Plasma samples (n = 20 per pregnant group) were obtained from non-pregnant and pregnant women in the first (FT, 6–12 weeks), second (ST, 22–24 weeks) and third (TT, 32–38 weeks) trimester. The number of exosomes and placental exosome contribution were determined by quantifying immunoreactive exosomal CD63 and placenta-specific marker (PLAP), respectively. The effect of exosomes isolated from FT, ST and TT on endothelial cell migration were established using a real-time, live-cell imaging system (Incucyte). Exosome plasma concentration was more than 50-fold greater in pregnant women than in non-pregnant women (p<0.001). During normal healthy pregnancy, the number of exosomes present in maternal plasma increased significantly with gestational age by more that two-fold (p<0.001). Exosomes isolated from FT, ST and TT increased endothelial cell migration by 1.9±0.1, 1.6±0.2 and 1.3±0.1-fold, respectively compared to the control. Pregnancy is associated with a dramatic increase in the number of exosomes present in plasma and maternal plasma exosomes are bioactive. While the role of placental cell-derived exosome in regulating maternal and/or fetal vascular responses remains to be elucidated, changes in exosome profile may be of clinical utility in the diagnosis of placental dysfunction.

Preeclampsia (PE) is one of the main causes of maternal and fetal morbidity and mortality in the world, causing nearly 40% of births delivered before 35 weeks of gestation. PE begins with inadequate trophoblast invasion early in pregnancy, which produces an increase in oxidative stress contributing to the development of systemic endothelial dysfunction in the later phases of the disease, leading to the characteristic clinical manifestation of PE. Numerous methods have been used to predict the onset of PE with different degrees of efficiency. These methods have used fetal/placental and maternal markers in different stages of pregnancy. From an epidemiological point of view, many studies have shown that PE is a disease with a strong familiar predisposition, which also varies according to geographical, socioeconomic, and racial features, and this information can be used in the prediction process. Large amounts of research have shown a genetic association with a multifactorial polygenic inheritance in the development of this disease. Many biological candidate genes and polymorphisms have been examined in their relation with PE. We will discuss the most important of them, grouped by the different pathogenic mechanisms involved in PE.

Normal pregnancy is considered as a Th2 type immunological state that favors an immune-tolerance environment in order to prevent fetal rejection. Preeclampsia (PE) has been classically described as a Th1/Th2 imbalance; however, the Th1/Th2 paradigm has proven insufficient to fully explain the functional and molecular changes observed during normal/pathological pregnancies. Recent studies have expanded the Th1/Th2 into a Th1/Th2/Th17 and regulatory T-cells paradigm and where dendritic cells could have a crucial role. Recently, some evidence has emerged supporting the idea that mesenchymal stem cells might be part of the feto-maternal tolerance environment. This review will discuss the involvement of the innate immune system in the establishment of a physiological environment that favors pregnancy and possible alterations related to the development of PE.

Recently, a noninvasive and highly proliferative stem cell population from menstrual blood called MenSCs has been identified. Despite their use in clinical studies, their immunomodulatory properties have not yet been investigated. In this context, we studied the immunosuppressive properties of MenSCs in comparison with the well-characterized bone marrow derived-MSCs (BM-MSCs). Using an in vitro proliferation assays, we showed that MenSCs displayed a lower suppressive effect on peripheral blood mononuclear cells and in particular on the proinflammatory CD4 1 IFN-c1 and CD81 IFNc 1 cells than BM-MSCs. Moreover, compared to BM-MSCs, MenSCs activated with IFN-c and IL-1b produced lower amounts of immunosuppressive factors such as IDO, PDL-1, PGE2, and Activin A and exhibited a substantial lower expression level of IFN-c receptor subunits. In the collagen induced arthritis model, while BM-MSCs administration resulted in a potent therapeutic effect associated with a significant decrease of proinflammatory T cell frequency in the lymph nodes, MenSCs injection did not. In contrast, in the xeno-GVHD model, only MenSCs administration significantly increased the survival of mice. This beneficial effect mediated by MenSCs was associated with a higher capacity to migrate into the intestine and liver and not to their anti-inflammatory capacities. All together our results demonstrate for the first time that the therapeutic potential of MSC in the experimental xeno-GVHD model is independent of their immunosuppressive properties. These findings should be taken into consideration for the development of safe and effective cell therapies. STEM CELLS 2016;34:456-469 SIGNIFICANCE STATEMENTIn the present study we report for the first time the immunosuppressive properties of MenSCs. We showed that they present lower immunosupressive properties compared to bone marrowMSCs, evidenced by lower expression of several immunomodulatory factors, and the absence of beneficial effect in experimental arthritis model. However, their therapeutic effect was maintained in the xeno-GVHD model, but this was independent on their antiinflammatory capacities. Since the use of MenSC has being proposed for several clinical trials the information provided here raises the alertness for evaluating carefully their potential side effects, a key prerequisite for the development of safe cell therapies.

Background: Several clinical scales have been developed for predicting stroke recurrence. These clinical scores could be extremely useful to guide triage decisions. Our goal was to compare the very early predictive accuracy of the most relevant clinical scores [age, blood pressure, clinical features and duration of symptoms (ABCD) score, ABCD and diabetes (ABCD2) score, ABCD and brain infarction on imaging score, ABCD2 and brain infarction on imaging score, ABCD and prior TIA within 1 week of the index event (ABCD3) score, California Risk Score, Essen Stroke Risk Score and Stroke Prognosis Instrument II] in consecutive transient ischemic attack (TIA) patients. Methods: Between April 2008 and December 2009, we included 1,255 consecutive TIA patients from 30 Spanish stroke centers (PROMAPA study). A neurologist treated all patients within the first 48 h after symptom onset. The duration and typology of clinical symptoms, vascular risk factors and etiological work-ups were prospectively recorded in a case report form in order to calculate established prognostic scores. We determined the early short-term risk of stroke (at 7 and 90 days). To evaluate the performance of each model, we calculated the area under the receiver operating characteristic curve. Cox proportional hazards multivariate analyses determining independent predictors of stroke recurrence using the different components of all clinical scores were calculated. Results: We calculated clinical scales for 1,137 patients (90.6%). Seven-day and 90-day stroke risks were 2.6 and 3.8%, respectively. Large-artery atherosclerosis (LAA) was observed in 190 patients (16.7%). We could confirm the predictive value of the ABCD3 score for stroke recurrence at the 7-day follow-up [0.66, 95% confidence interval (CI) 0.54–0.77] and 90-day follow-up (0.61, 95% CI 0.52–0.70), which improved when we added vascular imaging information and derived ABCD3V scores by assigning 2 points for at least 50% symptomatic stenosis on carotid or intracranial imaging (0.69, 95% CI 0.57–0.81, and 0.63, 95% CI 0.51–0.69, respectively). When we evaluated each component of all clinical scores using Cox regression analyses, we observed that prior TIA and LAA were independent predictors of stroke recurrence at the 7-day follow-up [hazard ratio (HR) 3.97, 95% CI 1.91–8.26, p < 0.001, and HR 3.11, 95% CI 1.47–6.58, p = 0.003, respectively] and 90-day follow-up (HR 2.35, 95% CI 1.28–4.31, p = 0.006, and HR 2.20, 95% CI 1.15–4.21, p = 0.018, respectively). Conclusion: All published scores that do not take into account vascular imaging or prior TIA when identifying stroke risk after TIA failed to predict risk when applied by neurologists. Clinical scores were not able to replace extensive emergent diagnostic evaluations such as vascular imaging, and they should take into account unstable patients with recent prior transient episodes.

In the last years, mesenchymal stem cell (MSC)-based therapies have become an interesting therapeutic opportunity for the treatment of rheumatoid arthritis (RA) due to their capacity to potently modulate the immune response. RA is a chronic autoimmune inflammatory disorder with an incompletely understood etiology. However, it has been well described that peripheral tolerance defects and the subsequent abnormal infiltration and activation of diverse immune cells into the synovial membrane, are critical for RA development and progression. Moreover, the imbalance between the immune response of pro-inflammatory and anti-inflammatory cells, in particular between memory Th17 and memory regulatory T cells (Treg), respectively, is well admitted to be associated to RA immunopathogenesis. In this context, MSCs, which are able to alter the frequency and function of memory lymphocytes including Th17, follicular helper T (Tfh) cells and gamma delta (γδ) T cells while promoting Treg cell generation, have been proposed as a candidate of choice for RA cell therapy. Indeed, given the plasticity of memory CD4 + T cells, it is reasonable to think that MSCs will restore the balance between pro-inflammatory and anti-inflammatory memory T cells populations deregulated in RA leading to prompt their therapeutic function. In the present review, we will discuss the role of memory T cells implicated in RA pathogenesis and the beneficial effects exerted by MSCs on the phenotype and functions of these immune cells abnormally regulated in RA and how this regulation could impact RA progression.

Hypoxia‐inducible factor 1 α (HIF1α), a regulator of metabolic change, is required for the survival and differentiation potential of mesenchymal stem/stromal cells (MSC). Its role in MSC immunoregulatory activity, however, has not been completely elucidated. In the present study, we evaluate the role of HIF1α on MSC immunosuppressive potential. We show that HIF1α silencing in MSC decreases their inhibitory potential on Th1 and Th17 cell generation and limits their capacity to generate regulatory T cells. This reduced immunosuppressive potential of MSC is associated with a metabolic switch from glycolysis to OXPHOS and a reduced capacity to express or produce some immunosuppressive mediators including Intercellular Adhesion Molecule (ICAM), IL‐6, and nitric oxide (NO). Moreover, using the Delayed‐Type Hypersensitivity murine model (DTH), we confirm, in vivo, the critical role of HIF1α on MSC immunosuppressive effect. Indeed, we show that HIF1α silencing impairs MSC capacity to reduce inflammation and inhibit the generation of pro‐inflammatory T cells. This study reveals the pivotal role of HIF1α on MSC immunosuppressive activity through the regulation of their metabolic status and identifies HIF1α as a novel mediator of MSC immunotherapeutic potential.

A series of 2,6,9-trisubstituted purine derivatives have been synthesized and investigated for their potential role as antitumor agents. Twelve compounds were obtained by a three step synthetic procedure using microwave irradiation in a pivotal step. All compounds were evaluated in vitro to determine their potential effect on cell toxicity by the MTT method and flow cytometry analysis on four cancer cells lines and Vero cells. Three out of twelve compounds were found to be promising agents compared to a known and effective anticancer drug, etoposide, in three out of four cancer cell lines assayed with considerable selectivity. Preliminary flow cytometry data suggests that compounds mentioned above induce apoptosis on these cells. The main structural requirements for their activity for each cancer cell line were characterized with a preliminary pharmacophore model, which identified aromatic centers, hydrogen acceptor/donor center and a hydrophobic area. These features were consistent with the cytotoxic activity of the assayed compounds.