Shiga toxins (Stxs) produced by Shigella dysenteriae type 1 and enterohemorrhagic Escherichia coli are the most common cause of hemolytic-uremic syndrome (HUS). It is well established that vascular endothelial cells, mainly those located in the renal microvasculature, are targets for Stxs. The aim of the present research was to evaluate whether E. coli-derived Shiga toxin 2 (Stx2) incubated with human microvascular endothelial cells (HMEC-1) induces release of chemokines and other factors that might stimulate platelet function. HMEC-1 were exposed for 24 h in vitro to Stx2, lipopolysaccharide (LPS), or the Stx2-LPS combination, and chemokine production was assessed by immunoassay. More interleukin-8 was released than stromal cell-derived factor 1␣ (SDF-1␣) or SDF-1␤ and RANTES. The Stx2-LPS combination potentiated chemokine release, but Stx2 alone caused more release of SDF-1␣ at 24 h than LPS or Stx2-LPS did. In the presence of low ADP levels, HMEC-1 supernatants activated platelet function assessed by classical aggregometry, single-particle counting, granule secretion, P-selectin exposure, and the formation of platelet-monocyte aggregates. Supernatants from HMEC-1 exposed only to Stx2 exhibited enhanced exposure of platelet P-selectin and platelet-THP-1 cell interactions. Blockade of platelet cyclooxygenase by indomethacin prevented functional activation. The chemokine RANTES enhanced platelet aggregation induced by SDF-1␣, macrophage-derived chemokine, or thymus and activationregulated chemokine in the presence of very low ADP levels. These data support the hypothesis that microvascular endothelial cells exposed to E. coli O157:H7-derived Stx2 and LPS release chemokines and other factors, which when combined with low levels of primary agonists, such as ADP, cause platelet activation and promote the renal thrombosis associated with HUS.

Background: Diabetes mellitus (DM) patients lose their ability to control normal blood glucose levels, resulting in high blood glucose levels (hyperglycemia). Hyperglycemia causes DM complications. This involves responses of vascular endothelial cells (VECs) to hyperglycemia, affecting inflammatory process and platelet activity. Ecto-enzyme CD39 is expressed on VECs, catalyzing the hydrolysis of ATP and ADP to AMP and, consequently, regulating inflammatory process and platelet activation. Objective: We studied whether high glucose concentration has an effect on CD39 expression on VECs. Methods: Cultured human umbilical vein endothelial cells (HUVEC) were used as a model of study. HUVEC were cultured in different glucose conditions (4, 9, 24, and 34 mM) for 24 hours. Cell viability was assessed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-based assay and expression of CD39 was examined by using SDS-PAGE and western blot techniques. Results: HUVEC were cultured in normal (4 and 9 mM) or high (24 and 34 mM) glucose concentrations for short term (24 hours). The results showed that high glucose (24 and 34 mM) reduced cell viability to 89.5 ± 11.3 and 86.3 ± 13.5 (mean ± SD), compared with control (4 mM), respectively. High glucose also induced increases in CD39 expression in HUVEC. Conclusion: High glucose decreases cell viability and increases CD39 expression in HUVEC, suggesting involvement of CD39 in cell responses to high glucose.

Background: Hyperlipidemia is an important risk factor of cardiovascular diseases (CVD), whose pathogenesis involves vascular endothelial dysfunction. Therefore, a specific marker of endothelial dysfunction, serum E-selectin, was assessed in Thai hyperlipidemia adults.Methods: Subjects who had no history of hypertension, diabetes and other serious illness were recruited and classified as normolipidemia (n=100) and hyperlipidemia (n=100), by using the levels of blood lipids (hyperlipidemia: total cholesterol >200 mg/dl, low density lipoprotein cholesterol (LDL-C) >130 mg/dl, and triglyceride >150 mg/dl). Clinical data were collected, and laboratory analysis was done. Serum levels of uric acid, fasting blood glucose (FBS), blood urea nitrogen (BUN), and creatinine were measured by the dry chemistry automate analyzer. Serum E-selectin was measured by using the enzyme-linked immunosorbent assay.Results: The hyperlipidemia subjects had significantly higher serum E-selectin levels than the normolipidemia subjects (18.98±11.58.56 versus 8.85±4.02 ng/ml). E-selectin was significantly correlated with blood lipids; total cholesterol, triglyceride, LDL-C, and HDL-C (r=0.477, 0.441, 0.453, and -0.191, respectively). Moreover, significant correlations of E-selectin with uric acid and fasting blood glucose were also found (r=0.155 and 0.166, respectively).Conclusions: Serum E-selectin levels increased in hyperlipidemia and correlated with uric acid and fasting blood glucose, reflecting the association between hyperlipidemia and pathogenesis of CVD, Therefore, it emphasizes the importance of hyperlipidemia management.

Background: Adiponectin secreted by adipocytes plays a key role in insulin sensitivity, anti-inflammation, and antiatherosclerosis. It is involved in several conditions including obesity, type 2 diabetes mellitus, cardiovascular disease, and chronic kidney disease (CKD). Glomerular filtration rate is monitored to indicate the kidney function and CKD progression. Objective: To assess the serum adiponectin levels in individuals with normal and mildly decreased glomerular filtration rate, analyze the association of serum adiponectin with various physical and biological parameters, and test whether serum adiponectin is the risk factor of mildly decreased glomerular filtration rate. Methods: This cross-sectional study was conducted in 172 individuals with 35-60 years of age. Serum samples were collected and divided into two groups, based on estimated glomerular filtration rate (eGFR): 90 with normal eGFR (G1, eGFR ≥90 mL/min/1.73 m 2 ) and 82 with mildly decreased eGFR (G2, eGFR = 60-89 mL/min/1.73 m 2 ). Anthropometric data were recorded. Serum adiponectin was measured by enzyme-linked immunosorbent assay. Results: Serum adiponectin levels were significantly increased in individuals with mildly decreased eGFR (G2), compared to G1 (8.23 ± 3.26 mg/mL and 6.57 ± 3.24 mg/mL, respectively; P = 0.001). Serum adiponectin was positively associated with age and high-density lipoprotein cholesterol but negatively associated with weight, body mass index, triglyceride, and waist and hip circumferences. Univariate analysis showed that serum adiponectin was significantly correlated with mildly decreased eGFR; however, when adjusting for confounding factors, there were no correlations. Furthermore, multivariate regression analysis showed that individuals at the age of 46-55 years (4.0; 95% CI: 1.9-8.3) and > 55 years (11.4; 95% CI: 3.7-35.5) were significantly correlated with mildly decreased eGFR. Conclusions: Serum adiponectin was significantly elevated in individuals with mildly decreased eGFR and may be a modulation factor, but was not an independent risk factor for mildly kidney damage. Further study is needed to clarify its potential benefits as monitoring biomarker for CKD progression.