PI3K/Akt signaling in peripheral T lymphocytes from systemic lupus erythematosus patients.

PI3K/Akt/mTOR signaling pathway plays an important role in cellular proliferation and growth signaling. It was demonstrated that murine models presenting activated PI3K/Akt/mTOR signaling pathway in lymphocytes develop features of systemic autoimmunity, linking this pathway to autoimmune diseases. Therefore, the goal of our study was to analyze this signaling axis in Systemic Lupus Erythematosus (SLE), the prototype of systemic autoimmune diseases, focusing on Akt and p70S6k, two components of this pathway. Our results demonstrated that both expression and phosphorylation levels of Akt are more increased in SLE than in healthy donors (HDs) CD4+ T cells suggesting an up-regulation of PI3K and mTOR activities. This result was also suggested when p70S6k, one of mTOR substrate, was evaluated. Indeed, in SLE CD4+ T cells an enhancement of p70S6k activity, in direct correlation with its expression level, was found. Since p27kip1, an inhibitor of cell cycle progression, is one of the Akt substrates, we analyzed its expression level in relationship with cell cycle progression and apoptosis. The results demonstrated that p27kip1 expression level was significantly decreased in SLE than in HDs CD4+ T cells. In SLE p27kip1 level was inversely correlated with the percentage of peripheral lymphocytes in apoptosis and in S phase of the cell cycle. Therefore, the increased activity of PI3K/Akt/mTOR signaling pathway and, as a result, the drop of p27kip1 levels observed in CD4+ T cells isolated from SLE patients might explain the accumulation of SLE lymphocytes in S and G2/M cell cycle phases where they undergo apoptosis.

Quantification and molecular characterization of regulatory T cells in connective tissue diseases.

The aim of our study was to investigate and characterize regulatory T cells (Treg) in peripheral blood of patients with connective tissue diseases (Systemic lupus erythematosus, systemic sclerosis, Sjögren's syndrome, poly- and dermatomyositis) as compared with blood from healthy controls. Treg cells were quantified and phenotypically characterized by flow cytometry while the expression level of Foxp3 mRNA was evaluated by real time PCR. A reduced percentage of peripheral blood Treg cells was found in patients than in controls, irrespective of the type of connective tissue disease. Treg cells, especially those expressing one of the phenotypical markers, seemed to differ not only between patients and healthy controls but also among types of diseases. Additionally, the presence of autoantibodies as well as disease activity appeared to be correlated with particular Treg cell populations, especially those expressing one of the examined phenotypical markers. Correlations with therapy suggested that glucocorticoids plus antimalarial or other immunosuppressor drugs diminished the percentage of Treg cells, especially of those with memory phenotype. These findings indicated dysregulations at the level of Treg cells and suggested an involvement of these cells in the pathology of connective tissue diseases. Moreover, our data are in agreement with the suggestion that Treg cells could be therapeutic targets for some autoimmune diseases.

Patients with primary antiphospholipid syndrome and coronary microvascular dysfunction--a distinct clinical subset.

UNLABELLED: Morbidity of patients with cardiac syndrome X (CSX) is high. Impairment of microvascular endothelial function has been suggested to be a mechanism of the disease. The study was undertaken to assess some of the characteristics of patients with primary antiphospholipid syndrome (pAPS) and CSX. METHODS: We studied 36 patients with CSX, 14 patients having pAPS and 10 healthy controls. Patients evaluation included: clinical examination, 12-lead ECG, effort treadmill test (protocol Bruce modified), determination of plasma triglycerides, cholesterol, antiphospholipid antibodies (APLA). There were determined as markers of the inflammatory state: serum phospholipase (PL-A2) and peripheral neutrophils activity. RESULTS: Patients with pAPS presented normal values of serum cholesterol and triglycerides levels, normal PL-A2 activity, moderate superoxide anion generation. Patients without APLA presented hyperlipidemia, increased PL-A2 activity, increased superoxide anion generation. During the follow-up period we found a correlation between P1-A2 activity and ischemic episodes, but only in patients with CSX and pAPS there were registered cardiovascular events. CONCLUSION: Patients with SCX and pAPS represent a distinct clinical subset, being characterized by minimal inflammation, absence of usual risk factors for coronary heart disease, more severe prognosis related to recurrent thromboses and the need for early anticoagulant therapy.

Platelet-activating factor acetylhydrolase activity in patients with chronic stable angina (preliminary results).

Coronary atherosclerotic disease is related to endothelial inflammation and dysfunction, thrombosis and plaque instability. Different inflammatory markers are studied in stable angina and coronary acute syndromes, in order to stratify better the risk and to prevent the cardiovascular events. Platelet-activating factor (PAF) and platelet activating factor acetylhydrolase (PAF-AH) represent a complex with proinflammatory actions, possibly related to progression of atherosclerotic lesions. In our study, we investigated PAF-AH activity in 30 patients with stable angina, trying to demonstrate a relation of PAF-AH activity with the severity of the coronary disease.