Simultaneous measurement of endothelial cell damage, elastase release and chemiluminescence response during interaction between polymorphonuclear leukocytes and endothelial cells

Parthenolide and its photochemically synthesized 1(10)Z isomer: chemical reactivity and structure-activity relationship studies in human leucocyte chemotaxis

The present study has achieved the photochemical conversion of a germacrolide into a melampolide. The investigation on their chemical properties allowed us to evaluate the minimum interatomic distance needed for transannular bridging of C(10) ring in germacrolides and to explain the regiochemical selectivity of electrophilic cyclizations. The antiinflammatory activity of parthenolide and its semisynthetic derivatives was evaluated by in vitro chemotaxis assay with human neutrophiles. These structure-activity relationship studies have led to hypothesize a new pharmacophore and have provided useful information for computationally designed drugs.

Protective Effect of Elastase Inhibition Against Myocardial Dysfunction and Injury Induced by Ischemia and Reperfusion in Isolated Rat Hearts

BACKGROUND: Elastase release has been incriminated in the genesis of reperfusion-induced myocardial dysfunction and injury, and elastase inhibitors have been reported to reduce myocardial dysfunction in dogs subjected to coronary artery occlusion and reperfusion. METHODS AND RESULTS: To examine if elastase inhibition will modify myocardial dysfunction and injured induced by ischemia and reperfusion in isolated hearts, hearts from male Sprague Dawley rats were subjected to 30 minutes of total ischemia followed by 30 minutes of reperfusion. Ischemia-reperfusion resulted in myocardial dysfunction (increase in coronary perfusion pressure and decrease in myocardial contraction), injury (measured as creatine kinase release), and lipid peroxidation (myocardial malondialdehyde). Perfusion of hearts with an elastase inhibitor, ICI200,880, protected against myocardial dysfunction, injury and lipid peroxidation following ischemia-reperfusion. As expected, perfusion with superoxide dismutase protected the hearts against hemodynamic deterioration following ischemia-reperfusion. In in vitro studies, there was no direct effect of ICI200,880 on superoxide anion generation. CONCLUSIONS: ICI200,880 seems to exert cardioprotective effects against ischemia-reperfusion-induced injury and myocardial dysfunction in isolated buffer-perfused hearts, most likely by an elastase-like protease inhibitory activity.

Chemiluminescence response and adherence of neutrophils to cultured endothelial cells--influence of immunoglobulin G

The effect of different concentrations (0.8, 4.35, 8.7, 17.5, 25 and 35 mg/mL) of intravenous immunoglobulin G (Endobulin) on neutrophil-endothelial cell interaction was studied using an in vitro model of human umbilical cord vein endothelial cells and human neutrophils. Because adherence of neutrophils to endothelial cells is an essential component in inflammatory processes leading to endothelial cell injury the influence of immunoglobulin G on adherence has been investigated. A second aim of the present study was to determine changes in chemiluminescence response of neutrophils during adherence to endothelial cells. Production of oxygen-derived metabolites, measured by chemiluminescence response of neutrophils, decreased significantly in the presence of 8.7 mg immunoglobulin/mL test during coincubation of neutrophils and endothelial cells (p < 0.025). The adherence of neutrophils to endothelial cells was significantly decreased at a concentration of 8.7 mg immunoglobulin/mL test (p < 0.025). The present results indicate that this preparation of immunoglobulin G might exert a protective effect on neutrophil-endothelial cell interaction by decreasing adherence of neutrophils to endothelial cells and by scavenging reactive oxygen metabolites. metabolites. Therefore, the current investigation points to a probable protective effect of immunoglobulin G in oxidative diseases, such as the adult respiratory distress syndrome.

Effect of prostaglandin E1 on chemiluminescence response and adherence of human polymorphonuclear leukocytes to human cultured endothelial cells of prostaglandin E1 treated polytraumatized patients

We investigated the effect of prostaglandin E1 on human polymorphonuclear leukocytes, in vivo. Polymorphonuclear leukocytes of a prostaglandin E1 and placebo study group were harvested and their function, as production of oxygen-derived metabolites and adherence to human cultured endothelial cells, was compared. Additionally, data obtained from polymorphonuclear leukocytes of a prostaglandin E1 and placebo group were compared with data obtained from polymorphonuclear leukocytes from 28 blood donors, who served as a control group. Production of oxygen-derived metabolites by polymorphonuclear leukocytes during contact with endothelial cells was measured by chemiluminescence. Chemiluminescence was significantly (p < 0.01) increased in the placebo group in comparison to the control group decreasing to values of control group after 6 d (post-trauma). Chemiluminescence response was not significantly suppressed in patients treated with prostaglandin E1 in comparison to the placebo group. Adherence of polymorphonuclear leukocytes (placebo group) to endothelial cells was significantly increased (p < 0.01) within the first 6d post-trauma. Following day 6, values were in the same range as values for the control group. Adherence was not significantly suppressed in patients treated with prostaglandin E1 in comparison to the placebo group. In conclusion, prostaglandin E1 at a dose of 20 ng/kg bw/min does not influence production of oxygen-derived metabolites and adherence in polytraumatized patients in comparison to a placebo group. Additionally, production of oxygen-derived metabolites by polymorphonuclear leukocytes in response to endothelial cells is shown and it is evident that endothelial cells might influence production of oxygen derived metabolites by polymorphonuclear leukocytes.

Zymosan-induced luminol-amplified chemiluminescence of whole blood phagocytes in experimental and human hyperthyroidism

Luminol-amplified CL of whole blood phagocytes was studied in rats given 3 consecutive doses of 0.1 mg L-triiodothyronine T3/kg or in hyperthyroid patients, after stimulation by zymosan. In both cases, CL was significantly increased, an effect which was produced independently of the opsonization of the zymosan particles and markedly inhibited by azide. The in vitro addition of T3 or L-thyroxine (T4) to whole blood phagocytes from normal rats did not modify the opsonized zymosan-dependent CL, when assayed at the concentrations found in euthyroid subjects or in hyperthyroid patients. Administration of propylthiouracil (400 mg/day for 2-3 months) to hyperthyroid patients reduced the CL response observed prior to treatment, to values comparable to those found in the euthyroid group. These data indicate that hyperthyroidism elicits an enhanced respiratory burst activity of whole blood phagocytes, probably related to adaptive changes induced by thyroid hormone on the mieloperoxidase-H2O2 system, rather than to direct actions of the hormone molecule or changes in the opsonic capacity of plasma.

In vitro effect of ascorbic acid on neutrophil-endothelial cell interaction

The effect of different concentrations (0.06, 0.6 and 6.0 mmol/L) of ascorbic acid on neutrophil-endothelial interaction was studied using an in vitro model of human umbilical cord vein endothelial cells and human neutrophils. The aim of the study was to determine changes in chemiluminescence response of neutrophils during adherence to endothelial cells. Because adherence of neutrophils to endothelial cells is an essential component in inflammatory processes leading to endothelial cell injury, the influence of ascorbic acid on adherence and endothelial cell injury have been investigated. Production of oxygen-derived metabolites, measured by chemiluminescence response of neutrophils, decreased significantly in the presence of 6 mmol/L ascorbic acid during coincubation of neutrophils and endothelial cells (p < 0.025). The adherence of neutrophils to endothelial cells was significantly decreased at a concentration of 6 mmol/L (p < 0.0005). The inhibition of neutrophil adherence to endothelial cells was correlated with a diminished neutrophil-mediated endothelial cell injury during incubation with 6 mmol/L ascorbic acid (p < 0.0005). The present results indicate that ascorbic acid might exert a protective effect on neutrophil-mediated endothelial cell injury by decreasing adherence of neutrophils to endothelial cells and by scavenging reactive oxygen metabolites. Moreover, the current investigation points to probable protective effect of ascorbic acid on oxidant-mediated cell damage in diseases (e.g., Adult Respiratory Distress Syndrome).