Effect of glycated insulin on the blood-brain barrier permeability: An in vitro study.

Altered blood-brain barrier (BBB) permeability may contribute to pathogenesis of diabetes-related central nervous system disorders. Considering the presence of glycated insulin in plasma of type 2 diabetic patients, we hypothesized that glycated insulin could induce changes in paracellular permeability in BBB. Therefore, the authors decided to study the effect of glycated insulin on paracellular permeability in a BBB model and the change induced in insulin conformation upon glycation. In this study, the structural modification was examined by fluorescence and circular dichroism spectroscopies and dynamic light scattering. Cell proliferation and production of ROS in astrocytes and HUVEC cells were analyzed by MTT and spectrofluorometric assays, respectively. Apoptosis induction was determined and confirmed by flow cytometry and western blot analyses, respectively. The permeability was measured Lucifer yellow and FITC-Dextran. According to our results, glycated insulin presented altered conformation and more exposed hydrophobic patches than insulin. Formation of oligomeric species and advanced glycated end products (AGEs) were determined. Lower cell viability, higher apoptosis, and more ROS were detected upon treatment of cells with glycated insulin. Finally, glycated insulin led to increased Lucifer yellow and FITC-dextran transportation across the BBB model which could result from ROS producing and apoptosis-inducing activities of AGE-insulin.

Comparative effects of Artemisia dracunculus, Satureja hortensis and Origanum majorana on inhibition of blood platelet adhesion, aggregation and secretion.

Platelet hyperactivity, resulting in platelet adhesion to the vessel wall, is one of the most important factors responsible for thrombosis and the incidence of cardiovascular diseases. In this study we were aimed to investigate and compare the inhibitory effects of the methanol extracts of three herb species on adhesion of the activated platelet to laminin-coated plates, aggregation and protein secretion. Artemisia dracunculus (tarragon), Satureja hortensis (summer savory) and Origanum majorana (marjoram) are used as blood anti-coagulator in Iranian folk medicine. Human platelets were prepared and incubated with different concentrations of the test samples (equivalent to 50-200 microg of each of the plant leaves powder/mL) for 60 min. The treated and untreated platelets were then activated with thrombin (0.25 U/mL) and their adhesion to laminin-coated plates was investigated. Based on our observations, the methanol extract of A. dracunculus, S. hortensis and O. majorana, at a concentration of 200 microg/mL, inhibited platelet adhesion to laminin-coated wells by 51%, 48% and 40%, respectively. In addition to alternation of cell adhesive properties, self aggregation and protein secretion of the treated platelets were also affected upon treatment with the crude methanol extracts. These observations provide the basis for the traditional use of these herbs in treatments of cardiovascular diseases and thrombosis.

Inhibition of blood platelet adhesion, aggregation and secretion by Artemisia dracunculus leaves extracts.

BACKGROUND: Platelet hyperactivity plays an important role in atherosclerosis and arterial thrombosis. Artemisia dracunculus L. (tarragon) is a common table vegetable all over Iran and known for its anticoagulant activity in Iranian folk medicine. OBJECTIVE: The present study was undertaken to investigate the effect of Artemisia dracunculus leaves methanol crude extract and its chloroform fraction on platelet aggregation, secretion and adhesion to laminin coated plates. MATERIALS AND METHODS: Human platelets were incubated with different concentrations of the test sample (equivalent to 25-200 mug of plant leaves powder/ml). The treated and untreated platelets were then activated with thrombin and adhesion to the laminin coated plates were evaluated. RESULTS: Based on our observations, the methanol extract and its chloroform fraction, at a concentration of 200 mug/ml, inhibited platelet adhesion to laminin coated wells by 50% and 60%, respectively. In addition to alternation of cell adhesive properties, protein secretion and self aggregation of the treated platelets were decreased upon treatment with the crude extract and its chloroform fraction. CONCLUSIONS: Our results showed that the methanol crude extract and chloroform fraction of tarragon could inhibit platelets adhesion, aggregation and secretion. These findings provide scientific basis for the traditional use of tarragon as a blood-diluting factor, as locally called, or as an anticoagulant.