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D Bouchier-Hayes

Publications and source records attributed to D Bouchier-Hayes.

At least 37 records · Page 2Linked to original sources
PubMed2001

Immune function, telomerase, and angiogenesis in patients with primary, operable nonsmall cell lung carcinoma: tumor size and lymph node status remain the most important prognostic features.

BACKGROUND: Lung carcinoma usually is advanced at the time of presentation and frequently shows metastatic spread. In recent times, prognostic factors such as c-erbB-2 in patients with breast carcinoma have provided useful information and beneficial therapeutic targets. The objective of this study was to evaluate angiogenesis, immune function, and telomerase expression in patients with nonsmall cell lung carcinoma (NSCLC) to determine their prognostic significance. METHODS: Immunohistochemistry was used to evaluate the expression of human telomerase reverse transcriptase (hTERT; n = 115 patients), interleukin-2r (IL-2r; n = 40 patients), microvessel density (MVD; n = 81 patients), and vascular endothelial growth factor (VEGF; n = 61 patients). Three-year survival follow-up information was available for most patients, and a comprehensive review of clinicopathologic features was carried out. RESULTS: Fifty percent of tumors showed nuclear staining for hTERT, 55% of tumors showed some degree of lymphocyte IL-2r expression, 33% of tumors were recorded with an MVD that was higher than average, and VEGF staining was detected in 85% of tumors. None of the parameters measured had an impact on survival. hTERT expression was correlated with lymph node status. Lymph node status and tumor size were identified as independent prognostic factors. CONCLUSIONS: This study failed to identify a marker of prognosis for patients with NSCLC other than tumor size and lymph node status in this population. Telomerase expression was associated with metastases, raising the possibility that this enzyme is involved in the metastatic process. Tumor cell VEGF expression was identified frequently: This growth factor may have potential as a target for antiangiogenic therapy. Lung carcinoma typically is the result of large numbers of mutations. Further understanding of the biologic implications of these mutations will lead to the development of effective prognostic markers and treatments for patients with NSCLC.

Adult↗
PubMed2001

Thermotolerance protects against endotoxin-mediated microvascular injury.

An early event in endotoxin-induced tissue injury is adhesion and migration of leukocytes through the endothelium. This is a three-stage process, initially low-grade selectin-mediated adhesion, seen as a decrease in rolling velocity, followed by integrin-mediated adhesion and transmigration. Thermotolerance has been shown to reduce tissue injury and mortality induced by endotoxin. The aim of this study was to investigate the effect of thermotolerance on leukocyte-endothelial interactions. Intravital video microscopy was used to examine hemodynamic parameters, leukocyte rolling, adhesion, and migration in rat mesenteric postcapillary venules. Sprague-Dawley rats were randomized into control, lipopolysaccharide (LPS), and thermotolerance + LPS groups. Thermotolerance was induced 18 h prior to administration of LPS by elevating core body temperature to 41 + 0.5 degrees C for 15 min. LPS (055:B5 15 mg/kg) was administered via the jugular vein after baseline recording. Leukocyte rolling velocity and the number of adherent and migrated leukocytes were measured by intravital microscopy at baseline 0 min and 10, 30, 60, and 90 min after LPS administration. Heat shock protein 72 (HSP72) expression in tissues was determined by Western immunoblotting. The results indicated that LPS administration significantly decreased leukocyte rolling velocity during endotoxemia and increased leukocyte adhesion (10.3 +/- 1.67, 13.2 +/- 1.40, and 10.0 +/- 1.57/100 microm) and migration (5.7 +/- 1.02 and 8.3 +/- 1.76/field) at 30, 60, and 90 min after LPS injection (P < 0.01 vs baseline and control group). Thermotolerance maintained leukocyte rolling velocity and significantly reduced leukocyte adhesion (5.7 +/- 0.88 and 4.0 +/- 0.68/100 microm) and migration (2.8 +/- 0.32 and 3.0 +/- 0.68/field) at 30 and 60 min after LPS administration (P < 0.01 and 0.05 vs LPS group). Expression of HSP72 was induced in mesentery, gut, and lung by thermotolerance. This study indicates that thermotolerance attenuated LPS-induced microvascular injury by decreasing leukocyte-endothelial adhesion and migration.

Animals↗
PubMed2001

Pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, attenuates renal injury in an experimental model of ischemia-reperfusion.

BACKGROUND: Renal dysfunction due to ischemia-reperfusion (IR) injury is a common problem following renovascular surgery or kidney transplantation. There is a lot of emerging evidence that statins, 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors, have anti-inflammatory properties and exert direct beneficial effects on the vascular endothelium. The aim of this study was to determine if pretreatment with pravastatin would attenuate the acute renal dysfunction that occurs following IR injury in an experimental model. MATERIALS AND METHODS: Male Sprague-Dawley rats were randomized into four groups (n = 7 per group): control, uninephrectomy, IR group, and IR group pretreated with pravastatin (0.4 mg/kg/day for the preceding 5 days). Following a left nephrectomy the IR injury was induced by cross-clamping the right vascular pedicle for 30 min followed by reperfusion for 2 h. In a separate experiment (n = 6 per group) renal function was assessed 12 and 24 h after reperfusion. RESULTS: IR injury causes significant renal dysfunction characterized by oliguria, 0.11 (0.05) ml/h, decreased glomerular filtration rate (GFR), 0.02 (0.01) ml/min; and marked protein leakage, 7.21 (1.3) g/L, 2 h postreperfusion. This renal dysfunction was also evident 12 and 24 h postreperfusion. This was in contrast to values of 0.61 (0.13) ml/h, 0.23 (0.01) ml/min, and 1.67 (0.12) g/L in the uninephrectomy-only group and values of 2 ml/h, 7.3 ml/min, and 0.72 g/L for uninjured time-matched controls. Pretreatment with pravastatin significantly attenuated IR-induced renal injury, improving urine production to 0.62 (0.2) ml/h and GFR to 0.14 (0.02) ml/min and diminishing protein leakage to 3.76 (0.7) g/L at the 2-h time point. This renoprotective effect was also evident 12 and 24 h postreperfusion. This renal protection was associated with an upregulation of constitutive endothelial nitric oxide synthase in the pravastatin-treated group. CONCLUSION: These results show that pravastatin may play a role in modulating renal impairment following aortic or transplantation surgery, allowing earlier recovery from an IR injury.

Animals↗
PubMed2001

Human neutrophils facilitate tumor cell transendothelial migration.

Tumor cell extravasation plays a key role in tumor metastasis. However, the precise mechanisms by which tumor cells migrate through normal vascular endothelium remain unclear. In this study, using an in vitro transendothelial migration model, we show that human polymorphonuclear neutrophils (PMN) assist the human breast tumor cell line MDA-MB-231 to cross the endothelial barrier. We found that tumor-conditioned medium (TCM) downregulated PMN cytocidal function, delayed PMN apoptosis, and concomitantly upregulated PMN adhesion molecule expression. These PMN treated with TCM attached to tumor cells and facilitated tumor cell migration through different endothelial monolayers. In contrast, MDA-MB-231 cells alone did not transmigrate. FACScan analysis revealed that these tumor cells expressed high levels of intercellular adhesion molecule-1 (ICAM-1) but did not express CD11a, CD11b, or CD18. Blockage of CD11b and CD18 on PMN and of ICAM-1 on MDA-MB-231 cells significantly attenuated TCM-treated, PMN-mediated tumor cell migration. These tumor cells still possessed the ability to proliferate after PMN-assisted transmigration. These results indicate that TCM-treated PMN may serve as a carrier to assist tumor cell transendothelial migration and suggest that tumor cells can exploit PMN and alter their function to facilitate their extravasation.

Adenocarcinoma↗
PubMed2001

Role of taurine in preventing acetaminophen-induced hepatic injury in the rat.

Acetaminophen overdose causes acute liver injury in both humans and animals. This study was designed to investigate the potential role of the conditionally essential amino acid taurine in preventing acetaminophen-induced hepatotoxicity. Male Sprague-Dawley rats were administered acetaminophen (800 mg/kg) intraperitoneally. Taurine (200 mg/kg) was given 12 h before, at the time of, and 1 or 2 h after acetaminophen injection. Acetaminophen treatment increased the plasma levels of aspartate transaminase, alanine aminotransferase, and alkaline phosphatase and caused hepatic DNA fragmentation and hepatocyte necrosis. Taurine administered before, simultaneously with, or 1 h after acetaminophen resulted in significant improvement in hepatic injury as represented by decrease of hepatocellular enzyme release and attenuation of hepatocyte apoptosis and necrosis, and this correlated with taurine-mediated attenuation of hepatic lipid peroxidation. These results indicate that taurine possesses prophylactic and therapeutic effects in acetaminophen-induced hepatic injury.

Acetaminophen↗
PubMed2001

TGF-beta1 is elevated in breast cancer tissue and regulates nitric oxide production from a number of cellular sources during hypoxia re-oxygenation injury.

Cellular response to treatment is dependent on the metabolic preconditioning of individual cells, which is a reflection of environmental conditions. Within solid tumours there are areas of different oxygen tension, which, we hypothesise, may indicate that cells are exposed to conditions that change continually. Other characteristics of the solid-tumour microenvironment include the production of growth factors, one of which is transforming growth factor (TGF)-beta1. As part of this study, we measured TGF-beta1 and found it raised in the serum of breast cancer patients compared with controls (98.24+/-13.25 vs. 48.87+/-12.14 ng/mL; P < 0.05; n = 7), and in the conditioned medium of breast tumour explant tissue compared with matched normal tissue (21.1+/-5.3 vs. 4.7+/-1.2 ng TGF-beta1/gram of tissue; P < 0.05; n = 11). Nitric oxide (NO) is a cytotoxic molecule produced by a large number of cells and thought to have antimetastatic properties. In order to observe the effect of conditions within breast tumours on NO production, we exposed macrophages, endothelial cells and tumour cells to hypoxia re-oxygenation in vitro, both in the presence and absence of TGF-beta1. Hypoxia stimulated increased NO production in both macrophages (normoxia: 0.34+/-0.04 nmol/L nitrite vs. hypoxia: 1.04+/-0.18 nmol/L nitrite; P < 0.05) and endothelial cells (normoxia: 0.02+/-0.01 nmol/L nitrite vs. hypoxia: 0.21+/-0.07 nmol/L nitrite; P < 0.05). NO production in macrophages, endothelial cells and tumour cells was reduced significantly following hypoxia in the presence of TGF-beta1 in a concentration-dependent manner. These results suggest that, within breast tumours, tumour-derived TGF-beta1 in combination with environmental conditions may result in decreased local NO production, which could have implications for tumour growth.

Breast Neoplasms↗
PubMed2000

Thermotolerance preserves endothelial vasomotor function during ischemia/reperfusion.

Ischemia/reperfusion (I/R) results in endothelial dysfunction, seen as loss of endothelium-dependent vasodilatation. In prolonged ischemia, this can result in marked vasospasm or no reflow in the microvasculature. Thermotolerance (T) attenuates I/R-induced microvascular injury. The aim of this study was to investigate the effect of thermotolerance on I/R-induced vasomotor changes and "no reflow." Sprague-Dawley rats were randomized into an ischemia/reperfusion group (I/R group) and a group in which thermotolerance (41 + 0.5 degrees C for 15 min 18 h prior to I/R) was induced (T + I/R group). IR injury was established by occlusion of the superior mesenteric and celiac vascular pedicle for 30 min, followed by 60 min of reperfusion. Vasomotor function [arteriolar constriction:dilatation (C:D) ratio] measured by response to acetylcholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) and "no-reflow" phenomenon were determined in mesenteric arterioles by intravital microscopy. Data are expressed as means +/- SEM and were analyzed using ANOVA and chi(2) test. I/R caused a significant decrease in endothelium-dependent vasodilatation (C:D = 1.37+/-0.31 in IR group vs. 2.06+/-0.20 in baseline, P<0.01) and no reflow in arterioles in 16 of 28 unheated rats. Endothelium-independent dilatation was not altered by I/R. Thermotolerance attenuated this impairment of endothelium-dependent dilatation (P<0.01 vs. IR; C:D = 1.95+/-0.19) and reduced no-reflow phenomenon to 4 of 16 rats (P<0.05 vs. IR). This study demonstrated that thermotolerance preserves endothelial vasomotor function and markedly reduces "no reflow" in arterioles.

Animals↗
PubMed2000

Diaphragmatic dysfunction secondary to experimental lower torso ischaemia-reperfusion injury is attenuated by thermal preconditioning.

BACKGROUND: Preconditioning describes the process whereby tissue exposure to a subcritical stress confers protection from subsequent injuries. This study assessed diaphragmatic muscle function after lower torso ischaemia-reperfusion (IR) and the role of thermal preconditioning in attenuation of this injury. METHODS: Sprague-Dawley rats were randomized into three groups (24 per group): a control group, an IR group that had aortic cross-clamping for 1 h followed by reperfusion, and a third group that received thermal preconditioning 18 h before IR. Diaphragmatic function was assessed at 24 h, 48 h and 7 days. RESULTS: IR resulted in significant diaphragmatic twitch and tetanic dysfunction compared with control muscle. Thermal preconditioning significantly attenuated this injury (P < 0.05). Mean(s.e.m.) muscle twitch and tetanic forces in the IR group were 204.9(17.2) and 282.7(19.2) g respectively at 24 h. Corresponding twitch and tetanic forces in preconditioned muscle were 270.4(25.1) and 552.0(35.2) g. CONCLUSION: This study demonstrated that systemic IR injury produced a respiratory muscle mechanical dysfunction that was attenuated by thermal preconditioning, at 24 h, 48 h and 7 days. Preconditioning may have a role in clinical practice, particularly before elective surgery.

Animals↗
PubMed2000

Neutrophil-induced transmigration of tumour cells treated with tumour-conditioned medium is facilitated by granulocyte-macrophage colony-stimulating factor.

OBJECTIVE: To investigate the effect of different cytokines that are present in tumour-conditioned medium on human neutrophil (PMN)-induced tumour cell transmigration. DESIGN: Laboratory study. SETTING: University hospital, Ireland. MATERIAL: Isolated human PMN and cultured human breast tumour cell line, MDA-MB-231. INTERVENTIONS: Human PMN treated with either tumour-conditioned medium or different media neutralised with monoclonal antibodies (MoAb), and MDA-MB-231 cells were plated on macrovascular and microvascular endothelial monolayers in collagen-coated transwells to assess migration of tumour cells. MAIN OUTCOME MEASURES: Cytokines present in tumour-conditioned medium, PMN cytocidal function and receptor expression, and tumour cell transmigration. RESULTS: tumour-conditioned medium contained high concentrations of granulocyte-macrophage colony-stimulating factor (GM-CSF), vascular endothelial growth factor (VEGF), and interleukin 8 (IL-8), but not granulocyte colony-stimulating factor (G-CSF) and interleukin 3 (IL-3). Anti-GM-CSF MoAb significantly reduced PMN-induced transmigration of tumour cells treated with tumour-conditioned medium (p < 0.05), whereas anti-VEGF and anti-IL-8 MoAbs did not affect their migration. In addition, anti-GM-CSF MoAb, but not anti-VEGF or anti-IL-8 MoAb, reduced PMN CD11b and CD18 overexpression induced by tumour-conditioned medium (p < 0.05). CONCLUSION: These results indicate that the GM-CSF that is present in tumour-conditioned medium may be involved, at least in part, in alterations in PMN function mediated by the medium and subsequently PMN-induced transmigration of tumour cells.

Breast Neoplasms↗
PubMed2000

Taurine protects against early and late skeletal muscle dysfunction secondary to ischaemia reperfusion injury.

OBJECTIVE: To assess the efficacy of the cytoprotective B-amino acid taurine in prevention of skeletal muscle dysfunction secondary to ischaemia-reperfusion (IR) injury. DESIGN: Randomised controlled animal study. SETTING: Biomedical research laboratory, teaching hospital, Republic of Ireland. ANIMALS: 96 Sprague Dawley rats. INTERVENTIONS: Rats were randomised into three groups (n = 24/group): control (sham); ischaemia-reperfusion (untreated); and ischaemia-reperfusion + taurine. A further 24 rats were given taurine alone. The rat cremaster skeletal muscle model of four hours of ischaemia followed by reperfusion was used. Taurine 4%wt/vol was given in the animals' water throughout the experiment, beginning 48 hours before the ischaemia was initiated. OUTCOME MEASURES: 8 rats were killed from each group and muscle contractile function was assessed using electrical field stimulation in a tissue bath at 24 hrs, 48 hrs and 7 days. RESULTS: Ischaemia followed by 24 hours, 48 hours or 7 days of reperfusion resulted in significant reduction in both muscle twitch and tetanic contractile function (p < 0.05). This was reversed by taurine, which resulted in significant preservation of twitch and tetanic contractility at all time points including one week of reperfusion (p < 0.05). There was no difference in muscle function between muscle treated with taurine after ischaemia-reperfusion and control muscle, with the same operation but without ischaemia, from 48 hours onwards. CONCLUSIONS: These data show that pharmaceutical use of the endogenous amino acid taurine, unlike many-other agents, protects electrophysiological function in skeletal muscle against both early and late ischaemia-reperfusion injury.

Animals↗
PubMed2000

Immunohistochemical measurement of tumor vascular endothelial growth factor in breast cancer. A more reliable predictor of tumor stage than microvessel density or serum vascular endothelial growth factor.

Microvessel density counting is commonly proposed as a method of assessing angiogenesis. However, results have been difficult to reproduce because of many methodological inconsistencies. Vascular endothelial growth factor (VEGF), an angiogenic regulator, is also a poor prognostic indicator in breast cancer, correlating in many studies with microvessel density. In this study, VEGF and microvessel density counting were examined as methods of assessing angiogenesis in breast cancer and correlated with tumor stage. A representative tumor section was stained with anti-CD34 and anti-VEGF. Microvessel density was evaluated using the manual "hot-spot" procedure and a semiquantitative image analysis system. Serum VEGF levels were available from an additional nine patients. Results were analyzed using Kendall's tau correlation. Tumor stage correlated with tumor VEGF, but not with microvessel "hot-spot" or vessel counts. There was no correlation between scores obtained from the manual or semiquantitative methods. Serum VEGF did not correlate with either tumor VEGF or tumor stage. The prognostic importance of VEGF in invasive breast cancer is associated with tumor stage. Measurement of tumor VEGF, as an indicator of angiogenesis, is more reliable prognostically than measurement of microvessel density or serum VEGF. Routine measurement of microvessel density in breast cancer is less reliable.

Adult↗
PubMed2000

Taurine prevents interleukin-2-induced acute lung injury in rats.

BACKGROUND: The therapeutic efficacy of interleukin-2 (IL-2) has been limited by a dose-dependent vascular leak syndrome. This may be related to neutrophil-mediated endothelial injury. Taurine has been shown to decrease this injury in vitro. This study investigates the role of taurine in preventing IL-2-induced lung injury, and the role of neutrophil-endothelial interactions in mediating this injury. METHODS: Study 1: Sprague-Dawley rats (n = 12/groups) were randomised to controls, IL-2-treated (1 x 10(6) units), and IL-2-treated with taurine (4% solution, orally for 48 h prior to IL-2 therapy). Lung injury was measured by extravascular lung water (wet/dry weight) and bronchoalveolar lavage protein concentration. Neutrophil infiltration was evaluated by measuring myeloperoxidase activity and bronchoalveolar lavage neutrophil concentration. Study 2: Rats (n = 10/group) were randomised into the same groups as study 1. Neutrophil-endothelial interactions in mesenteric vessels were assessed by intravital microscopy at half-hourly intervals. RESULTS: Taurine reduced IL-2-induced acute lung injury as reflected by a decrease in wet-to-dry lung weight ratio from 7.2 +/- 0.5 in the IL-2 group to 4.7 +/- 0.3 in the taurine group (p < 0.05), and a decrease in bronchoalveolar neutrophil concentration from 823 +/- 19.5 in the IL-2 group to 538 +/- 18 in the taurine group (p < 0.05). Intravital microscopy demonstrated that IL-2 increased leucocyte adhesion and migration in mesenteric vessels, and that this was significantly reduced by taurine. CONCLUSION: These data suggest that taurine prevents IL-2-induced tissue injury in part by decreasing neutrophil-endothelial interactions.

Acute Disease↗
PubMed2000

Head and neck schwannomas--a 10 year review.

Schwannomas of the head and neck are uncommon tumours that arise from any peripheral, cranial or autonomic nerve. Twenty-five to 45 per cent of extracranial schwannomas occur in the head and neck region and thus are usually in the domain of the otolaryngologist. They usually present insidiously and thus are often diagnosed incorrectly or after lengthy delays, however, better imaging and cytological techniques have lessened this to some degree more recently. For benign lesions conservative surgical excision is the treatment of choice bearing in mind possible vagal or sympathetic chain injury. Malignant schwannomas are best treated with wide excision where possible. The role of adjuvant therapy remains uncertain and irrespective of treatment modality prognosis is poor with an overall survival of 15 per cent. However, recent advances in ras oncogene inhibitors may hold hope for the future.

Adult↗
PubMed1999

Recombinant human manganese superoxide dismutase attenuates early but not delayed skeletal muscle dysfunction following reperfusion injury.

OBJECTIVES: to assess the efficacy of recombinant human manganese superoxide dismutase (rhMnSOD) in prevention of early and late skeletal muscle ischaemia-reperfusion injury mediated by superoxide (O2-). Design : randomised controlled trial. MATERIALS: seventy-two Sprague-Dawley rats (250-350 g) randomised to receive either 7.5 mg/kg of rhMnSOD or saline. Four hours of ischaemia was induced in the cremaster muscle by dissecting free and clamping its vascular supply. Cremaster muscle contractile function was assessed following 90 minutes, 24, 48 hours and one week of reperfusion. Electrophysiological muscle function was assessed using electrical field stimulation in an organ bath system. RESULTS: muscle function in the untreated groups following ischaemia reperfusion was significantly reduced at 90 minutes, 24, 48 hours and one week of reperfusion (p <0.05). rhMnSOD significantly protected and maintained normal muscle function at 24 and 48 hours (p <0.001). However at one week of reperfusion there was a reduction in function of the treated muscle, such that there was no significant difference between treated and untreated muscle at this point in time. CONCLUSIONS: these data demonstrate that skeletal muscle dysfunction after ischaemia reperfusion injury is attenuated at 24 and 48 hrs of reperfusion by the superoxide scavenger rhMnSOD. This protective effect is not maintained after seven days of reperfusion.

Animals↗
PubMed1999

Vitamin C reduces ischaemia-reperfusion-induced acute lung injury.

OBJECTIVES: to evaluate vitamin C supplementation in the prevention of ischaemia-reperfusion (I-R) induced acute lung injury. DESIGN: Sprague-Dawley rats (n =6/group) were randomised into Control, I-R and I-R pretreated with vitamin C (3.3 g over 5 days). Ischaemia-reperfusion injury was induced by 30 minutes infrarenal aortic cross-clamping and 120 minutes reperfusion. METHODS: pulmonary microvascular injury was measured by broncho-alveolar lavage protein concentration, pulmonary neutrophil infiltration by tissue myeloperoxidase activity and bronchoalveolar lavage neutrophil counts. In a second experiment (n =5/group) neutrophil respiratory burst activity was measured in Control and vitamin C groups. RESULTS: ischaemia-reperfusion resulted in a significant increase in both microvascular leakage and pulmonary neutrophil infiltration as measured by bronchoalveolar lavage protein concentration and pulmonary myeloperoxidase activity respectively. Pretreatment with vitamin C significantly attenuated both microvascular leakage and neutrophil infiltration. Neutrophil respiratory burst activity was significantly reduced in the vitamin C group (13.02 m.c.f.+/-0.3) compared with Control (19.04 m.c.f.+/-1. 9),p <0.02. CONCLUSION: these data suggest that oral vitamin C therapy protects against ischaemia-reperfusion-induced acute lung injury, possibly by attenuating neutrophil respiratory burst activity.

Animals↗
PubMed1999

Circulating granulocyte macrophage colony-stimulating factor in plasma of patients with the systemic inflammatory response syndrome delays neutrophil apoptosis through inhibition of spontaneous reactive oxygen species generation.

In the normal resolution of an acute inflammatory response apoptosis of neutrophils is essential to maintain immune homeostasis and limit inappropriate host tissue damage by decreasing neutrophil tissue load, function, and release of phlogistic reactive oxygen species and proteases. The systemic inflammatory response syndrome (SIRS), a massive pro-inflammatory immune state, is associated with delayed neutrophil apoptosis, however, the systemic circulating factors and intracellular signal transduction pathways important in regulating neutrophil apoptosis in SIRS are poorly described. Neutrophils isolated from patients with SIRS on admission to the intensive care unit showed significantly (p<.01) delayed spontaneous neutrophil apoptosis compared with healthy neutrophils as quantified using annexin V-FITC and terminal deoxyuridine triphosphate (dUTD) nick end labeling (TUNEL) flow cytometry methods. Plasma from SIRS patients markedly (41.5+/-7.2%, p<.01) inhibited apoptosis of healthy neutrophils compared with controls (69.7+/-4.8%) indicating the presence of soluble circulating factors that can modify the expression of neutrophil apoptosis. Various pro-inflammatory (IL-6, granulocyte macrophage colony-simulating factor, interleukin (IL)-1beta, tumor necrosis factor-alpha) mediators, known to modulate neutrophil apoptosis in vitro, were elevated in the plasma of our cohort of SIRS patients compared with controls. However, the anti-apoptotic effect of SIRS plasma was specifically attenuated (75.5%, p<.01) by neutralizing SIRS plasma of granulocyte macrophage-colony-stimulating factor, but not IL-6, IL-1beta, tumor necrosis factor-alpha. Although the anti-inflammatory cytokine IL-10 was elevated in SIRS plasma (median level 7.2 pg/mL), further boosting SIRS plasma with recombinant human IL-10 (10 ng/mL, levels found in septic shock patients) significantly countered (63.8%, p<.01) the inhibitory effect of SIRS plasma on neutrophil apoptosis. Suppression of neutrophil apoptosis was concomitant with delayed spontaneous elevation of reactive oxygen species, quantified as peroxide production, and reversed by addition of neutralizing antibodies to GM-CSF, and recombinant human IL-10 to SIRS plasma. These results identify circulating GM-CSF as a significant inhibitor of neutrophil apoptosis in patients with SIRS, and that this effect can be countered by boosting SIRS plasma with IL-10. GM-CSF and IL-10 appear to modulate neutrophil apoptosis by altering reactive oxygen species generation in neutrophils.

Adolescent↗
PubMed1999

Involvement of tyrosine protein kinase in IFN-gamma-induced human endothelial cell apoptosis.

Although it is well recognized that interferon-gamma (IFN-gamma) is involved in the development of systemic inflammatory response syndrome, a condition characterized by loss of endothelial barrier function, whether or not IFN-gamma has any direct effect on endothelial cell (EC) death is unclear. Furthermore, which signal transduction pathway involved in IFN-gamma-induced EC apoptosis remains to be elucidated. To answer these questions, we investigated the effect of IFN-gamma on EC death (apoptosis versus necrosis) and the underlying signal transduction pathway responsible for IFN-gamma-induced EC apoptosis. IFN-gamma resulted in a dose-dependent increase in EC apoptosis after 24 h incubation (p < .05). However, IFN-gamma did not induce EC necrosis. Tumor necrosis factor-alpha (TNF-alpha), but not lipopolysaccharide (LPS), had a augmentative effect on IFN-gamma-induced EC apoptosis (p < .05), while both of them alone failed to induce EC apoptosis. These results indicate that exposure of EC to IFN-gamma can cause apoptosis rather than necrosis. Both calcium ionophore, A23187, and the protein kinase C (PKC) activator phorbol-myristate-acetate (PMA) had a synergistic effect on IFN-gamma-induced EC apoptosis (p < .05). However, neither the calcium chelator 1,2-bis 2-aminophenoxy ethane-N,N,N',N'-tetraacetic acid (BAPTA), nor the PKC inhibitor 1 -5-isoquinolinysulfonyl 2-methyl piperazine (H-7) attenuated IFN-gamma-induced EC apoptosis. Three specific tyrosine protein kinase (TPK) inhibitors, herbimycin A, tyrphostin, and genistein, significantly inhibited IFN-gamma-induced EC apoptosis in a dose-dependent fashion (p < .05). Furthermore, the activation of TPK in EC by IFN-gamma was completely abrogated by these TPK inhibitors. These findings suggest that the signal transduction pathway required for induction of EC apoptosis by IFN-gamma is TPK dependent and is independent of calcium and PKC.

Adult↗