Predisposition to cortical neurodegenerative changes in brains of hypertension prone rats.

BACKGROUND: Substantial evidence suggests that hypertension is a significant risk factor for cognitive decline. However, it is unclear whether the genetic predisposition to hypertension is also associated with cellular dysfunction that promotes neurodegeneration. METHODS: Changes in blood pressure were evaluated following dietary salt-loading or administration of a regular diet in Sabra Normotensive (SBN/y) and Sabra Hypertension-prone rats (SBH/y). We performed quantitative RT-PCR and immunofluorescence staining in brain cortical tissues before salt loading and 6 and 9 months after salt loading. To examine the expression of brain cortical proteins involved in the gene regulation (Histone Deacetylase-HDAC2; Histone Acetyltransferase 1-HAT1), stress response (Activating Transcription Factor 4-ATF4; Eukaryotic Initiation Factor 2- eIF2α), autophagy (Autophagy related 4A cysteine peptidase- Atg4a; light-chain 3-LC3A/B; mammalian target of rapamycin complex 1- mTORC1) and apoptosis (caspase-3). RESULTS: Prior to salt loading, SBH/y compared to SBN/y expressed a significantly higher level of cortical HAT1 (protein), Caspase-3 (mRNA/protein), LC3A, and ATF4 (mRNA), lower levels of ATG4A (mRNA/protein), LC3A/B, HDAC2 (protein), as well as a lower density of cortical neurons. Following dietary salt loading, SBH/y but not SBN/y developed high blood pressure. In hypertensive SBH/y, there was significant upregulation of cortical HAT1 (protein), Caspase-3 (protein), and eIF2α ~ P (protein) and downregulation of HDAC2 (protein) and mTORC1 (mRNA), and cortical neuronal loss. CONCLUSIONS: The present findings suggest that genetic predisposition to hypertension is associated in the brain cortex with disruption in autophagy, gene regulation, an abnormal response to cellular stress, and a high level of cortical apoptosis, and could therefore exacerbate cellular dysfunction and thereby promote neurodegeneration.

Free circulating active elastase contributes to chronic inflammation in patients on hemodialysis.

Atherosclerosis and cardiovascular complications are prevalent among patients undergoing chronic hemodialysis (HD). In this population, peripheral polymorphonuclear leukocytes (PMNLs) are primed, releasing proinflammatory mediators such as elastase. Elastase is normally inhibited by a specific inhibitor, avoiding undesirable degradation of cellular and extracellular components. This study tested the hypothesis that in states of noninfectious inflammation, elastase is released by PMNLs and acts in an uncontrolled manner to inflict vascular damage. Blood was collected from patients undergoing HD and healthy controls (HC). PMNL intracellular and surface expressions of elastase were determined by quantitative real-time PCR, Western blotting, and flow cytometry. The elastase activity was evaluated using a fluorescent substrate. The levels of serum α1-antitrypsin (α1-AT), the natural elastase inhibitor, were determined by Western blot. Free active elastase was elevated in HD sera, whereas the levels of α1-AT were decreased compared with HC. The levels of the intracellular elastase enzyme and its activity were lower in HD PMNLs despite similar expression levels of elastase mRNA. Elastase binding to PMNL cell surface was higher in HD compared with HC. The increased circulating levels of free active elastase released from primed HD PMNLs together with the higher cell surface-bound enzymes and the lower levels of α1-AT result in the higher elastase activity in HD sera. This exacerbated elastase activity could lead to the endothelial dysfunction, as hypothesized. In addition, it suggests that free circulating elastase can serve as a new biomarker and therapeutic target to reduce inflammation and vascular complications in patients on hemodialysis.

Primed polymorphonuclear leukocytes from hemodialysis patients enhance monocyte transendothelial migration.

Increased counts and priming of peripheral polymorphonuclear leukocytes (PMNLs) are associated with future or ongoing atherosclerosis; however, the role of PMNLs in enhancing monocyte transendothelial migration is still unclear. Our aims were to examine endothelial and monocyte activation, transmigration, and posttransmigration activation induced ex vivo by in vivo primed PMNLs and the effect of antioxidants on the activation. A unique ex vivo coculture system of three cell types was developed in this study, enabling interactions among the following: primary human umbilical vein endothelial cells (HUVECs), monocytes (THP-1 cell line), and in vivo primed PMNLs from hemodialysis (HD) patients and healthy control (HC) subjects. The interactions among these cells were examined, and an intervention with superoxide dismutase and catalase was performed. Preexposed HUVECs to HD/HC PMNLs showed a significant monocyte transmigration yield, 120-170% above HCs. Monocyte exposure to HD PMNLs induced pre- and posttransmigration activation. When the three cell types were cocultivated at the same time, monocyte chemoattractant protein-1 protein levels released from HUVECs, and activation markers on HUVECs [CD54 and chemokine (C-X3-C motif) ligand 1] and monocytes [chemokine (C-X3-C) receptor 1 and chemokine (C-C motif) receptor 2] were increased. Monocyte transmigration yield decreased to 70% (compared with HC subjects) due to adherence and accumulation of monocytes to HUVECs. When superoxide dismutase and catalase were used, reduced HUVEC and monocyte activation markers brought the transmigration yields to control levels and abolished accumulation of monocytes, emphasizing the role of superoxide in this process. We conclude that peripheral primed PMNLs play a pivotal role in enhancing monocyte transendotelial migration, the hallmark of the atherosclerotic process. Primed PMNLs can be used as a mediator and a biomarker of atherosclerosis even before plaque formation.NEW & NOTEWORTHY Primed polymorphonuclear leukocytes are key mediators in monocyte transendothelial migration, a new understanding of the initiation of endothelial dysfunction and monocyte activation, transmigration, and accumulation in the subendothelial layer.

[LEVEL AND OXIDATION OF BETA 2-MICROGLOBULIN IN HEMODIALYSIS PATIENTS TREATED WITH INTRAVENOUS IRON DURING DIALYSIS WITH HIGH-FLUX COMPARED TO LOW-FLUX DIALYZERS].

INTRODUCTION: Serum levels of ß2-microglobulin (b2M) are significantly higher in patients with end stage renal failure undergoing hemodialysis (HD) and its accumulation accelerates Dialysis Related Amyloidosis (DRA). In HD patients low-flux dialysis, intravenous (IV) iron (administered for the treatment of anemia) affects ß2M removal during dialysis. IV iron also affects the oxidation of plasma proteins, including b2M. AIMS: To examine the effect of intravenous iron therapy on ß2M levels and oxidation in HD patients treated with high-flux compared with low-flux dialyzers. METHODS: Sixteen HD patients on chronic maintenance IV iron therapy were studied. Half of the patients were allocated to high-flux and half to low-flux dialysis. After five weeks, each patient was assigned to the second dialyzer. After two weeks of treatment with each dialyzer, blood samples were taken and serum levels of ß2M were measured. In addition, the hematocrit and iron status were measured. Part of the samples were used to evaluate oxidized ß2M. RESULTS: A significant increase in ß2M levels was found with low-flux dialysis, which further increased during dialysis with IV iron administration. High-flux dialysis therapy significantly lowered the ß2M levels, with a clear decrease during the dialysis session, that was unaffected by IV iron administration. A significant decrease in ß2M oxidation was found during highflux, but not low-flux dialysis. CONCLUSIONS: High-flux dialysis is more effective than lowflux in decreasing the levels and oxidation of ß2M. These observations may have significance in improving iron therapy, aimed to decrease or attenuate the appearance of DRA.

Does Pomegranate intake attenuate cardiovascular risk factors in hemodialysis patients?

BACKGROUND: Atherosclerotic cardiovascular disease (CVD) is the most common cause of morbidity and mortality among hemodialysis (HD) patients. It has been attributed, among other causes, to hypertension and dyslipidemia. The aim of the present study was to investigate the effect of a year-long consumption of Pomegranate juice (PJ), on two traditional cardiovascular (CV) risk factors: hypertension and lipid profile, as well as on cardiovascular events. METHODS: 101 HD patients were randomized to receive 100 cc of PJ (0.7 mM polyphenols) or matching placebo juice, three times a week for one year. The primary endpoints were traditional CV risk factors; blood pressure and lipid profile. Systolic, diastolic and pulse pressure, plasma levels of triglycerides (TG), high density lipoprotein (HDL), low density lipoprotein (LDL) and total cholesterol were monitored quarterly during the study year. Secondary endpoint was incidence of cardiovascular events. RESULTS: PJ consumption yielded a significant time response improvement in systolic blood pressure, pulse pressure, triglycerides and HDL level; an improvement that was not observed in the placebo intake group. These beneficial outcomes were more pronounced among patients with hypertension, high level of triglycerides and low levels of HDL. CONCLUSION: Regular PJ consumption by HD patients reduced systolic blood pressure and improved lipid profile. These favorable changes may reduce the accelerated atherosclerosis and high incidence of CVD among HD patients. TRIAL REGISTRATION: ClinicalTrials.gov registry, Identifier number: NCT00727519.

Oxidative modifications impair albumin quantification.

BACKGROUND: Hypoalbuminemia is a measure of malnutrition, inflammation and a predictor of mortality in uremia. It is controversial whether albumin levels per se are associated with the clinical outcomes in uremic patients. The co-occurrence of hypoalbuminemia and oxidative stress in hemodialysis (HD) patients led us to hypothesize that oxidative modifications of albumin decrease its detection and influence albumin quantification. METHODS: Albumin levels are determined in clinical laboratories mainly by the bromocresol green (BCG) spectrophotometric assay. The detection of serum albumin was investigated in HD patients and in healthy controls using an "albumin-detection index", defined as the ratio between BCG read-out (albumin-specific) to total albumin. The detection efficacy of albumin was also investigated in vitro, after glycoxidation, HOCl-mediated-oxidation, and metal-catalyzed-oxidation. Oncotic pressure was measured to assess albumin function. RESULTS: The albumin-detection index of patients was significantly lower compared with controls, correlating negatively with oxidative stress markers (serum advanced oxidation protein products-AOPP and glycoxidized serum albumin) and positively with serum albumin levels. The albumin-detection index was also decreased after in vitro oxidation. CONCLUSIONS: The study shows, both in vivo and in vitro, decreased detection of oxidized albumin by a commonly-used clinical assay, thus providing the molecular link between oxidative stress and hypoalbuminemia. Oxidative stress as reflected by hypoalbuminemia, rather than actual albumin levels, may be related to cardiovascular morbidity outcomes in HD patient.

Decreased TFF2 expression in the gastric antrum in patients infected with CagA-positive Helicobacter pylori.

BACKGROUND: The trefoils factor family is a relatively new family of peptides. Their abundant expression in the epithelial cells of the gastrointestinal tract in the normal physiological state and in various ulcerative conditions suggests an important role in mucosal defense and repair. Infection with Helicobacter pylori interferes with normal mucosal activity. OBJECTIVES: To investigate whether H. pylori infection alters the expression of trefoils TFF1 and TFF2 in the gastric mucosa of patients with H. pylori-associated chronic active gastritis, positive or negative for the CagA strain. METHODS: During investigation for dyspepsia, gastric biopsies and blood samples were obtained from patients who underwent upper gastrointestinal endoscopy. Rapid urease testing, histology for determination of H. pylori-associated CAG and Western analysis for TFF1 and TFF2 expression with antisera were performed. CagA state was determined using a commercial kit. RESULTS: TFF2 expression was significantly reduced in both groups of patients with H. pylori-associated CAG compared to healthy patients without H. pylori infection, particularly in CagA-positive patients. TFF1 expression showed a tendency of reduction (not significant) in this group only. CONCLUSIONS: These results suggest that H. pylori-associated CAG has a deleterious effect on the expression of TFF2 in the gastric antrum. This reduced expression may contribute to the damage induced to the gastric mucosa by H. pylori.

Epoetin-alpha: preserving kidney function via attenuation of polymorphonuclear leukocyte priming.

BACKGROUND: Polymorphonuclear leukocyte priming and low grade inflammation are related to severity of kidney disease. Erythropoietin-receptor is present on PMNLs. OBJECTIVESxi: To evaluate the effect of 20 weeks of epoetin-alpha treatment on PMNL characteristics in relation to the rate of kidney function deterioration in patients with chronic kidney disease. METHODS: Forty anemic chronic kidney disease patients, stage 4-5, were assigned to EPO and non-EPO treatment for 20 weeks. A group of 20 healthy controls was also studied. PMNL priming and PMNL-derived low grade inflammation were estimated, in vivo and ex vivo, before and after EPO treatment: The rate of superoxide release, white blood cells and PMNL counts, serum alkaline phosphatase and PMNL viability were measured. EPO-receptor on PMNLs was assayed by flow cytometry. The effect of 20 weeks of EPO treatment on kidney function was related to the estimated glomerular filtration rate. esults: EPO treatment attenuated superoxide release ex vivo and in vivo and promoted PMNL survival ex vivo. Decreased low grade inflammation was reflected by reduced WBC and PMNL counts and ALP activity following treatment. EPO retarded the deterioration in GFR. The percent of PMNLs expressing EPO-R was higher before EPO treatment and correlated positively with the rate of superoxide release. After 20 weeks of EPO treatment the percent of PMNLs expressing EPO-R was down-regulated. CONCLUSIONS: These non-erythropoietic properties of EPO are mediated by EPO-R on PMNLs, not related to the anemia correction. A new renal protection effect of EPO via attenuation of PMNL priming that decreases systemic low grade inflammation and oxidative stress is suggested.

The polymorphonuclear leukocyte contributes to the development of hypertension in the Sabra rat.

BACKGROUND: We previously showed that priming of the polymorphonuclear leukocyte (PMNL), inflammation and oxidative stress antecede the development of hypertension in the Sabra rat model of hypertension. The actual role of PMNLs and PMNL-mediated oxidative stress and inflammation in the development of hypertension in this model has remained, however, unresolved. OBJECTIVE: The aim of our study was to test the hypothesis that PMNLs and that the PMNL-associated NADPH oxidase contribute to the development of hypertension in the Sabra rat model. METHODS: To determine the contribution of the PMNL to the development of hypertension, we depleted Sabra hypertension-prone (SBH/y) animals from PMNLs with an anti-PMNL antibody, salt-loaded them and monitored their blood pressure over a period of 30 days. To determine the contribution of the NADPH oxidase on the development of hypertension, we inhibited the activity of this enzyme with phenylarsine oxide or apocynin in SBH/y rats while salt-loading the animals and followed the course of their blood pressure over 60 days. RESULTS: PMNL depletion attenuated significantly the development of hypertension in SBH/y rats. Inhibition of NADPH oxidase with phenylarsine oxide and apocynin markedly inhibited the development of hypertension in SBH/y rats, as well as decreased the rate of superoxide release, the level of PMNL CD11b and the PMNL count. CONCLUSION: These data are consistent with a significant contribution of PMNLs to the development of hypertension, and suggest that the mechanism may be related, at least in part, to PMNL-mediated oxidative stress and inflammation.

Salivary beta2-microglobulin analysis in chronic kidney disease and hemodialyzed patients.

BACKGROUND: Beta2-microglobulin (beta2m) is a major component in dialysis-related amyloidosis, a disabling disease affecting long-term dialysis patients. METHODS: Beta2m and other components were analyzed in saliva and serum from 53 individuals in 4 subgroups: healthy normal controls, diabetes mellitus (DM), chronic kidney disease (CKD) and hemodialysis (HD) patients. RESULTS: Median salivary and mean serum beta2m concentrations were 78% higher in both saliva (p = 0.048) and serum (p = 0.047) in DM patients; 118% (p = 0.016) and 907% (p = 0.007) higher, respectively, in CKD patients, and 328% (p = 0.0001) and 2,710% (p = 0.001) higher, respectively, in HD patients, compared with healthy controls. The correlation analysis between salivary and serum beta2m concentrations showed a low correlation rate in HD patients (r = -0.18), but was rather high in CKD patients (r = 0.50). CONCLUSIONS: Salivary analysis of beta2m is a reliable method for evaluating serum beta2m levels in CKD patients, and may help predict the potential for development of CKD-induced amyloidosis.

[Expression of inflammatory mediators in meningitis].

BACKGROUND: Infectious diseases cause a systemic inflammatory reaction. In some cases of meningitis it is difficult to determine whether the disease is of bacterial, viral or non-infectious origin. In order to distinguish between bacterial and viral diseases the levels of various inflammatory markers are used to determine the severity of the disease and the clinical prognosis. OBJECTIVE: The purpose of this study was to determine whether the levels of different markers can be used to distinguish between bacterial or viral meningitis or non-infectious neurological disease. METHODS: Patients with bacterial meningitis (n= 8), viral meningitis (n= 17), non-infectious neurological diseases (n = 17) and healthy subjects (n = 15) were studied. The levels of soluble CD14 (sCD 14), interleukin-6 (IL-6), interleukin-1beta (IL-1beta) and soluble adhesion molecule-1 (sICAM-1) were determined in the blood of all participants and in spinal fluid only in patients who had clinical indication to perform lumbar puncture. RESULTS: All the patients showed significant differences in the levels of blood and CSF markers measured compared to healthy subjects. In the blood, although some differences were significant, there was overlapping between all values of the measured markers in patient blood samples excluding IL-6, for which levels were significantly different between the bacterial and viral meningitis. Interestingly, the levels of all markers showed significant differences among all groups of patients. CONCLUSIONS: Among the blood markers examined, IL-6 can be used to distinguish between bacterial and viral diseases. However, the levels of cytokines examined in CSF, can serve to distinguish between bacterial and viral meningitis and non-infectious diseases.

In-vivo oxidized albumin- a pro-inflammatory agent in hypoalbuminemia.

Hypoalbuminemia of Hemodialysis (HD) patients is an independent cardiovascular risk factor, however, there is no mechanistic explanation between hypoalbuminemia and vascular injury. In the event of oxidative stress and inflammation to which HD patients are exposed, albumin is oxidized and undetected by common laboratory methods, rendering an apparent hypoalbuminemia. We wanted to show that these circulating modified oxidized albumin molecules cause direct vascular damage, mediating inflammation. Once these in-vivo albumin modifications were reduced in- vitro, the apparent hypoalbuminemia concomitantly with its inflammatory effects, were eliminated. Albumin modification profiles from 14 healthy controls (HC) and 14 HD patients were obtained by mass spectrometry (MS) analyses before and after reduction in- vitro, using redox agent 1,4 dithiothreitol (DTT). Their inflammatory effects were explored by exposing human umbilical endothelial cells (HUVEC) to all these forms of albumin. Albumin separated from hypoalbuminemic HD patients increased endothelial mRNA expression of cytokines and adhesion molecules, and augmented secretion of IL-6. This endothelial inflammatory state was almost fully reverted by exposing HUVEC to the in-vitro reduced HD albumin. MS profile of albumin modifications peaks was similar between HD and HC, but the intensities of the various peaks were significantly different. Abolishing the reversible oxidative modifications by DTT prevented endothelial injury and increased albumin levels. The irreversible modifications such as glycation and sulfonation show low intensities in HD albumin profiles and are nearly unobserved in HC. We showed, for the first time, a mechanistic link between hypoalbuminemia and the pro-inflammatory properties of in-vivo oxidized albumin, initiating vascular injury.

[Polymorphonuclear leukocyte priming and counts are in correlation with blood pressure parameters].

BACKGROUND: In hypertensive patients, the polymorphonuclear leukocytes (PMNLs) are primed, concomitantly contributing to oxidative stress and chronic low-grade inflammation. Furthermore, in the Sabra rat model of salt-induced hypertension, priming of PMNLs, oxidative stress and inflammation antecede the development of hypertension. In the present study we tested the hypothesis that PMNL priming and PMNL and white blood cells (WBC) counts are interrelated with blood pressure values. Therefore, we have evaluated the correlation between WBC and PMNL counts, PMNL priming parameters and blood pressure in untreated essential hypertension patients (EH) and age and gender healthy controls. METHODS: Diastolic blood pressure (DBP), systolic blood pressure (SBP) and mean arterial pressure (MAP) values were correlated by linear regression analysis with the rates of superoxide release from separated PMNLs and with WBC and PMNL counts. RESULTS: The rate of superoxide release from PMNLs was higher in EH patients compared to their healthy controls. The rate of superoxide release from PMNLs correlated with SBP, DBP and MAP. WBC and PMNL counts were all significantly correlated with blood pressure values. CONCLUSION: The results of the study offer an additional mechanism involving primed PMNLs and elevated PMNL counts in the pathogenesis of hypertension and its late cardiovascular complications.

[The effect of calcium channel blocker lercanidipine on lowgrade inflammation parameters in essential hypertension patients].

INTRODUCTION: Oxidative stress (OS), inflammation and insulin resistance are among the mechanisms that have been recently implicated in pathogenesis of essential hypertension (EH). Peripheral polymorphonuclear leukocytes (PMNLs) are primed in EH patients, releasing uncontrolled superoxide anion contributing to OS and chronic low-grade inflammation in these patients. PMNL priming correlates with insulin resistance and with PMNL intracellular calcium ([Ca2+]i). Recent studies have attributed additional anti-oxidative characteristics to the anti-hypertensive drug Lercanidipine (Vasodip), a third generation calcium-channel blocker. AIM: To evaluate possible novel effects of two months of Lercanidipine treatment on systemic and PMNL-related inflammation and on insulin resistance in EH patients. METHODS: Fifteen non-smoking EH patients with untreated mild to moderate high blood pressure (BP) and age- and gender-matched healthy controls (HC) were included in the study. Low-grade inflammation was expressed by PMNL counts and apoptosis, by plasma fibrinogen, CRP and albumin (as a negative acute phase reactant) levels. Fasting serum insulin levels served as a marker of insulin resistance. RESULTS: Inflammation parameters and insulin levels were higher in EH compared to HC. PMNL counts, fibrinogen and insulin levels positively correlated with mean arterial blood pressure values. Two months of Lercanidipine treatment showed a significant decrease in BP, PMNL counts and apoptosis, CRP and serum insulin levels and a significant increase in serum albumin levels. CONCLUSION: The authors imply that the low-grade systemic inflammation and insulin resistance detected in EH patients may be attenuated by the use of Lercanidipine, adding new unknown anti-inflammatory properties to this calcium channel blocker.

Punicalagin Induces Serum Low-Density Lipoprotein Influx to Macrophages.

High levels of circulating low-density lipoprotein (LDL) are a primary initiating event in the development of atherosclerosis. Recently, the antiatherogenic effect of polyphenols has been shown to be exerted via a mechanism unrelated to their antioxidant capacity and to stem from their interaction with specific intracellular or plasma proteins. In this study, we investigated the interaction of the main polyphenol in pomegranate, punicalagin, with apolipoprotein B-100 (ApoB100) that surrounds LDL. Punicalagin bound to ApoB100 at low concentrations (0.25-4 µM). Upon binding, it induced LDL influx to macrophages in a concentration-dependent manner, up to 2.5-fold. In contrast, another polyphenol which binds to ApoB100, glabridin, did not affect LDL influx. We further showed that LDL influx occurs specifically through the LDL receptor, with LDL then accumulating in the cell cytoplasm. Taken together with the findings of Aviram et al., 2000, that pomegranate juice and punicalagin induce plasma LDL removal and inhibit macrophage cholesterol synthesis and accumulation, our results suggest that, upon binding, punicalagin stimulates LDL influx to macrophages, thus reducing circulating cholesterol levels.

Unexpected Normal Colloid Osmotic Pressure in Clinical States with Low Serum Albumin.

BACKGROUND: In clinical states associated with systemic oxidative stress (OS) and inflammation such as chronic kidney disease (CKD), oxidative modifications of serum albumin impair its quantification, resulting in apparent hypoalbuminemia. As the maintenance of oncotic pressure/colloid osmotic pressure (COP) is a major function of albumin, this study examined the impact of albumin oxidation on COP, both in-vivo and in-vitro. METHODS: Patients with proteinuria and patients on chronic hemodialysis (HD) with systemic inflammation and OS were enrolled. Blood samples were collected from 134 subjects: 32 healthy controls (HC), proteinuric patients with high (n = 17) and low (n = 31) systemic inflammation and from 54 patients on chronic hemodialysis (HD) with the highest levels of OS and inflammation. RESULTS: In-vitro oxidized albumin showed significantly higher COP values than non-oxidized albumin at identical albumin levels. In vivo, in hypoalbuminemic HD patients with the highest OS and inflammation, COP values were also higher than expected for the low albumin levels. The contribution to COP by other prevalent plasma proteins, such as fibrinogen and immunoglobulins was negligible. We imply that the calculation of COP based on albumin levels should be revisited in face of OS and inflammation. Hence, in hypoalbuminemic proteinuric patients with systemic OS and inflammation the assumption of low COP should be verified by its measurements.

Exogenous superoxide mediates pro-oxidative, proinflammatory, and procoagulatory changes in primary endothelial cell cultures.

Endothelial dysfunction/activation underlies the development of long-term cardiovascular complications and atherosclerosis. The aim of this study was to examine a direct role for exogenous sublethal flux of superoxide on endothelial cell dysfunction. Human umbilical vein endothelial cells (HUVEC) were exposed to superoxide generated by 0.1 mM xanthine and 4 mU/ml xanthine oxidase for 15 min and essential endothelial functions were examined. Superoxide dismutase and/or catalase was used as scavenger for O(2)(-)/H(2)O(2) to determine the key culprit. HUVEC detachment was determined by neutral red uptake and apoptosis by annexin V binding. Inflammation was estimated by IL-8 mRNA expression and cellular adhesion molecules (CAM). eNOS and iNOS message and eNOS protein served as an indirect measure for NO. Procoagulable state was evaluated by estimating the intracellular tissue factor. Activation of endothelial NADPH oxidase was determined by lucigenin chemiluminescence. Sublethal superoxide dose evoked: (1) proinflammatory state manifested by increased IL-8 mRNA expression and CAM on the endothelial surface, (2) HUVEC apoptosis and activated endothelial NADPH oxidase, (3) increase in intracellular tissue factor, and (4) decrease in eNOS mRNA and protein and up-regulation of iNOS mRNA. We conclude that extracellular low flux of superoxide exhibits pleiotropic characteristics, triggering activation/dysfunction of endothelial cells.

Heparin Interaction with the Primed Polymorphonuclear Leukocyte CD11b Induces Apoptosis and Prevents Cell Activation.

Heparin is known to have anti-inflammatory effects, yet the mechanisms are not completely understood. In this study, we tested the hypothesis that heparin has a direct effect on activated polymorphonuclear leukocytes (PMNLs), changing their activation state, and can explain its anti-inflammatory effect. To test our hypothesis, we designed both in vitro and ex vivo studies to elucidate the mechanism by which heparin modulates PMNL functions and therefore the inflammatory response. We specifically tested the hypothesis that priming of PMNLs renders them more susceptible to heparin. Amplified levels of CD11b and increased rate of superoxide release manifested PMNL priming. Increase in cell priming resulted in a dose-dependent increase in heparin binding to PMNLs followed by augmented apoptosis. Blocking antibodies to CD11b inhibited heparin binding and abolished the apoptotic response. Moreover, heparin caused a significant dose-dependent decrease in the rate of superoxide release from PMNLs, which was blunted by blocking antibodies to CD11b. Altogether, this study shows that the interaction of heparin with the PMNL CD11b results in cell apoptosis and explains heparin's anti-inflammatory effects.

A link between polymorphonuclear leukocyte intracellular calcium, plasma insulin, and essential hypertension.

BACKGROUND: Intracellular ionized calcium ([Ca2+]i) is a key mediator in the activation and oxidant production by peripheral polymorphonuclear leukocytes (PMN). Primed PMN contribute to oxidative stress (OS) and inflammation in essential hypertension (EH). Elevated [Ca2+]i has been described in insulin-resistant states and in various cell types in EH but not in EH PMN. The aim of this study was to evaluate the levels of [Ca2+]i in peripheral EH PMN in relation to plasma insulin levels and blood pressure (BP). METHODS: The PMN were separated from blood of 20 nonsmoking, nonobese untreated EH patients, age range 20 to 60 years and from 20 age- and gender-matched healthy individuals (NC). Plasma glucose and insulin levels 2 h after a 75-g oral glucose load, reflected insulin resistance. PMN [Ca2+]i was measured by flow cytometry in isolated cells stained with Fluo-3. RESULTS: The EH PMNs showed significantly increased [Ca2+]i compared to NC PMN. Eighty percent of EH patients showed significantly higher plasma insulin levels after glucose load. Linear regression analysis showed significant correlation between 1) PMN [Ca2+]i and mean arterial pressure (MAP) (r = 0.5, P < .006); 2) PMN [Ca2+]i and fasting plasma insulin (r = 0.7, P < .005); and 3) fasting plasma insulin and MAP (r = 0.4, P < .04). CONCLUSIONS: This study adds PMN to previously described cells exhibiting elevated [Ca2+]i, contributing to OS and inflammation. The correlation of individual BP with both PMN [Ca2+]i and plasma insulin levels, together with the fact that elevated [Ca2+]i mediates PMN priming, suggest that elevated [Ca2+]i and insulin are involved in the pathogenesis of hypertension-induced vascular injury in EH.