dinoprost and Ischemia

The choroid is the main source of oxygen to the retina. In contrast to the adult, the absence of autoregulation of choroidal blood flow in the newborn leads to hyperoxygenation of the retina. In the immature retina which contains relatively low levels of antioxidants this hyperoxygenation favors peroxidation including the generation of biologically active isoprostanes, and results in vasoconstriction and vascular cytotoxicity leading to ischemia, which predisposes to the development of a vasoproliferative retinopathy, commonly termed retinopathy of prematurity. During frequently encountered oxidative stress to the perinate, the combined absence of vascular autoregulation and excessive oxygen delivery to the eyes of the developing subject is largely the result of a complex epigenetic and genetic interplay between prostanoids and nitric oxide (NO) systems on vasomotor regulation. The effects of certain prostaglandins are NO-dependent; conversely, those of NO have also been found to be largely prostaglandin I(2)-mediated in the eye; and NO synthase expression seems to be significantly regulated by other prostaglandins apparently through activation of functional perinuclear prostanoid receptors which affect gene transcription. The increased production of both prostaglandins and NO in the perinate augment ocular blood flow and as a result oxygen delivery to an immature retina partly devoid of antioxidant defenses. The ensuing peroxidation results in impaired circulation (partly thromboxane A(2)-dependent) and vascular integrity, leading to ischemia which predisposes to abnormal preretinal neovascularization, a major feature of ischemic retinopathy. Because tissue oxygenation is largely dependent upon circulation and critical in the generation of reactive oxygen species, and since the latter exert a major contribution in the pathogenesis of retinopathy of prematurity, it is important to understand the mechanisms that govern ocular blood flow. In this review we focus on the important and complex interaction between prostanoid, NO and peroxidation products on circulatory control of the immature retina.

Topics: Choroid; Dinoprost; Endothelial Growth Factors; Free Radicals; Humans; Infant, Newborn; Infant, Premature; Ischemia; Lipid Peroxidation; Lymphokines; Neovascularization, Pathologic; Nitrates; Nitric Oxide; Nitric Oxide Synthase; Oxidative Stress; Oxygen; Receptors, Prostaglandin E; Retina; Retinal Vessels; Retinopathy of Prematurity; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Platelets critically contribute to atherothrombosis and worsening ischaemia in patients with peripheral arterial disease (PAD), eventually leading to critical limb ischaemia (CLI). Furthermore, persistent platelet activation despite antiplatelet therapy has been reported in this setting. The prostacyclin analogue iloprost is currently recommended in CLI patients for its effects in relieving symptoms by promoting local perfusion. In this study, we investigated the effects of iloprost infusion on urinary 11-dehydro-TXB₂ and 8-iso-PGF(₂α) excretion rate, as in vivo indexes of thromboxane-dependent platelet activation and lipid peroxidation, respectively, and on platelet-derived proinflammatory sCD40L and nitric oxide bioavailability in 44 patients with CLI while on chronic treatment with low-dose aspirin. Daily iloprost infusion for one-week significantly decreased urinary 11-dehydro-TXB₂ [499 (277-807) vs. 380 (189-560) pg/mg creatinine, p < 0.0001] and 8-iso-PGF(₂α) [533 (316-842) vs. 334 (196-540) pg/mg creatinine, p < 0.0001] as well as plasma sCD40L [1540 (1005-3015) vs. 948 (845-2030) pg/ml, p < 0.0001]. Furthermore, a significant increase in plasma nitrate plus nitrite levels has been observed [26.8 (18.8-35.9) vs. 43.7 (33.0-75.5) μM, p < 0.0001]. A significant direct correlation was also found between urinary 8-iso-PGF(₂α) and 11-dehydro-TXB2 before and after iloprost treatment (Rho = 0.695, p < 0.0001). In conclusion, we report that a short-term course of iloprost is able to significantly reduce residual thromboxane biosynthesis, oxidative stress, endothelial dysfunction and platelet-derived inflammation in low-dose aspirin treated patients with CLI.

Topics: Aged; Aged, 80 and over; Aspirin; Biomarkers; Blood Platelets; CD40 Ligand; Chi-Square Distribution; Critical Illness; Dinoprost; Drug Administration Schedule; Female; Humans; Iloprost; Inflammation Mediators; Infusions, Intravenous; Ischemia; Italy; Lipid Peroxidation; Male; Middle Aged; Nitric Oxide; Oxidative Stress; Platelet Activation; Platelet Aggregation Inhibitors; Thromboxane B2; Time Factors; Treatment Outcome

Tempol, a superoxide dismutase-mimetic drug, has been shown to attenuate radical-induced damage, exerting beneficial effects in the animal models of oxidative stress and hypertension. This study evaluated the effect of Tempol on renal structural and functional alterations in two-Kidney, one-Clip hypertensive rats. In this study, young male Wistar rats had the left kidney clipped (2K1C), and sham-operated animals (Sham) were used as controls. Animals received Tempol (1mmol/L in drinking water) or vehicle for 5 weeks. Systolic blood pressure was evaluated once a week. At the end of the experimental protocol, the animals were placed in metabolic cages to collect urine (24h) and then anesthetized with thiopental (70mg/kg i.p.) to collect blood by puncturing the descending aorta for biochemical analysis, and the clipped kidney for morphological and immunohistochemical analyses. The vasodilator effect of Tempol was evaluated in mesenteric arterial bed (MAB) isolated from adult Wistar rats. The chronic treatment with Tempol prevented the development of hypertension and the increased plasma levels of urea, creatinine, and 8-isoprostane in 2K1C animals. Tempol also improved both glomeruli number and kidney volume to normal levels in the 2K1C+Tempol group. In addition, the treatment prevented the increased collagen deposition and immunostaining for renin, caspase-3, and 8-isoprostane in the stenotic kidney of 2K1C animals. Moreover, Tempol induced a dose-dependent vasodilator response in MAB from Wistar rats. These results suggest that Tempol protects the stenotic kidney against chronic ischemic renal injury and prevents renal dysfunction in the 2K1C model, probably through its antioxidant, vasodilator and antihypertensive actions.

Topics: Animals; Antioxidants; Biomimetic Materials; Blood Pressure; Caspase 3; Chronic Disease; Creatinine; Cyclic N-Oxides; Dinoprost; Hypertension; Ischemia; Kidney; Kidney Diseases; Kidney Glomerulus; Male; Oxidative Stress; Rats; Rats, Wistar; Renin; Spin Labels; Superoxide Dismutase; Urea; Vasodilation

Primary dysmenorrhea (PD) is a common gynecological disorder. Hitherto, animal models which recapitulate clinical features of PD have not been fully established. We aimed to examine whether a pain model in mice could mimic the clinic features of PD. After pretreated with estradiol benzoate (1 mg/kg/day) intraperitoneally (i.p.) for 3 consecutive days, non-pregnant female Imprinting Control Region mice (6-8 weeks old) was injected with 0.4 U of oxytocin to induce the stretching or writhing response which was recorded for a time period of 30 min. During the writhing period, the uterine artery blood flow alterations were examined by Doppler ultrasound detection. After writhing test, the uterine morphological changes were observed by hematoxylin and eosin (H&E) staining histopathology. In addition, enzyme-linked immunosorbent assay kit was used to measure the levels of prostaglandins F2α/prostaglandins E2 (PGF2α/PGE2) and TXB2 (a metabolite of TXA2)/6-keto-PGF1α (a metabolite of PGI2) in the uterine tissue homogenates and plasma, respectively. Western blot analyses were performed to determine the expressions of oxytocin receptor (OTR), beta2-adrenergic receptor (beta2-AR), and cyclooxygenase-2 (COX-2) in uterine, which are responsible for the uterine contraction. The writhing response only occurred in the estrogen pretreated female mice. The area of uterine myometrium significantly decreased along with the increased thickness in the oxytocin-induced estrogen pretreated mice model. The uterine artery blood flow velocity dropped, while the pulsatility index and resistance index slightly increased after the injection of oxytocin. The PGF2α/PGE2 level significantly increased and the plasma TXB2/6-keto-PGF1α level significantly enhanced. Compared with the control group, the uterine histopathology demonstrated moderate to severe edema of endometrium lamina propria. In consistent with the uterine morphological changes, a significant reduction of beta2-AR and a significant increase of OTR and COX-2 in the uterine tissue were observed. The writhing response was caused by the abnormal contraction of uterus. The uterine spasm and ischemia changes of oxytocin-induced estrogen pretreated female mice model were similar to the pathology of human PD. We reported an in vivo mice model, which can be used to study PD and for clinical therapeutic evaluations.

Topics: Animals; Blood Flow Velocity; Cyclooxygenase 2; Dinoprost; Dinoprostone; Disease Models, Animal; Dysmenorrhea; Female; Ischemia; Male; Mice, Inbred ICR; Myometrium; Receptors, Adrenergic, beta-2; Receptors, Oxytocin; Uterine Artery; Uterine Contraction; Uterus

15-F2t-isoprostane is not only a specific marker of lipid peroxidation but also demonstrated to have potent bioactivities and can exert deleterious effects via activating thromboxane A2 receptor (TxA2r). We already demonstrated that lipid peroxidation represents a mechanism of intestinal ischemia/reperfusion (I/R) injury. But no studies have focused on 15-F2t-isoprostane production and its biological actions on postischemic intestine during intestinal I/R. This study was carried to investigate whether the mechanism of endogenous 15-F2t-isoprostane action is involved in the pathogenesis of intestinal I/R and administration of synthetic 15-F2t-isoprostane could exacerbate intestinal insult after intestinal I/R in vivo and in vitro. In comparison with that of the sham control, we reported that endogenous 15-F2t-isoprostane was liberated following intestinal I/R injury in rats, and using the TxA2r antagonist SQ29548 resulted in significant intestinal protection, evidenced by reduced lipid peroxidation, inflammation, and alleviated intestinal mucosal microvascular vasoconstriction. Further research found that in vivo administration of synthetic 15-F2t-isoprostane exacerbated intestinal I/R injury by disturbing microvascular perfusion and accumulating anaerobic metabolism. Meanwhile, 15-F2t-isoprostane did not change Hypoxia/Reoxygenation-induced IEC-6 cell viability but aggravated HUVECs cell death in vitro. Collectively, our results showed that locally produced 15-F2t-isoprostane was in proportion to the severity of oxidative stress-induced intestinal injury and its detrimental effects can be attenuated through TxA2r inactivation. Exogenous 15-F2t-isoprostane exacerbated intestinal I/R injury, which may be contributable to its biological actions on endothelium, rather than intestinal epithelium.

Topics: Animals; Dinoprost; Intestinal Mucosa; Ischemia; Isoprostanes; Lipid Peroxidation; Male; Random Allocation; Rats; Rats, Sprague-Dawley; Reperfusion Injury

To investigate renal ischemia injury during renal hilar clamping (artery alone versus clamping artery/vein together) by evaluating ischemic damage via two different modalities in animal models-near-infrared tissue oximetry and 8-isoprostane levels.. Near-infrared renal oximetry measurements of Yorkshire swines (n = 4; 8 renal units) subject to hilar clamping were obtained at baseline, during warm ischemia (15- and 30-min trials) and after unclamping. Quantitation of 8-isoprostane levels is the second technique of quantitating interstitial fluid collected from a dialysis catheter placed through renal parenchyma of male Sprague-Dawley rats (n = 50) subject to hilar clamping during preclamp, clamp (either 15 or 30 min of hilum clamping), and post-clamp.. N ear-infrared tissue oximetry. In the 15-min trial, oxygen saturation decreased 6× faster with artery alone compared to artery/vein clamped together. In the 30-min trial, the decrease was 5× faster. Recovery of oxygen saturation with only artery clamped occurred more than 2× faster in the 15- and 30-min periods. Isoprostane. For 15-min clamp times, 8-isoprostane levels in the artery alone group demonstrated a 1.54 decrease in the artery clamped alone group (p = 0.006) versus artery/vein together: preclamp (11.47 and 11.63 pg/mL/g), clamp (14.61 and 17.70 pg/mL/g), and post-clamp (14.26 and 22.04 pg/mL/g).. Renal ischemia injury from clamping the renal artery alone was significantly less than clamping artery/vein together demonstrated in two different techniques. Recovery of oxygen saturation was twofold faster, and mean post-clamp 8-isoprostane levels demonstrated a 1.54-fold decrease with clamping renal artery alone compared to clamping artery/vein together.

Topics: Animals; Constriction; Dinoprost; Ischemia; Kidney; Male; Models, Animal; Oximetry; Rats; Rats, Sprague-Dawley; Renal Artery; Renal Veins; Spectroscopy, Near-Infrared; Swine

Mesenchymal stem cells are useful for vascular regeneration of injured tissues. Macrophages are involved in acute or chronic inflammatory diseases, and interleukin-1β (IL-1β), a proinflammatory cytokine, plays a key role in the activation of macrophages within injured tissues. To explore the role of macrophages on mesenchymal stem cell-mediated vascular regeneration, we examined the effects of IL-1β-activated macrophages on differentiation of human adipose tissue-derived mesenchymal stem cells (hASCs) to smooth muscle cells (SMCs) and the vascular regenerative capacity of the differentiated SMCs in a hindlimb ischemia animal model.. We demonstrate that IL-1β-conditioned medium from RAW 264.7 macrophages induces differentiation of human adipose tissue-derived mesenchymal stem cells to α-smooth muscle actin-positive SMCs, and the differentiated SMCs exhibited increased contractility in response to KCl and carbachol treatment. Transplantation of the differentiated SMCs attenuated severe hindlimb ischemia and promoted vascular regeneration. IL-1β treatment stimulated secretion of prostaglandin F(2α) from RAW 264.7 cells. Small interfering RNA-mediated silencing of the prostaglandin F(2α) receptor completely abrogated IL-1β conditioned medium-stimulated α-smooth muscle actin expression. Moreover, prostaglandin F(2α) treatment stimulated expression of α-smooth muscle actin in human adipose tissue-derived mesenchymal stem cells.. These results suggest that IL-1β-activated macrophages promote differentiation of human adipose tissue-derived mesenchymal stem cells to SMCs through a prostaglandin F(2α)-mediated paracrine mechanism.

Topics: Actins; Adipose Tissue; Animals; Biomarkers; Cell Differentiation; Cell Line; Coculture Techniques; Culture Media, Conditioned; Dinoprost; Disease Models, Animal; Hindlimb; Humans; Inflammation Mediators; Interleukin-1beta; Ischemia; Macrophage Activation; Macrophages; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice; Mice, Nude; Muscle, Skeletal; Myocytes, Smooth Muscle; Neovascularization, Physiologic; Paracrine Communication; Receptors, Prostaglandin; Regional Blood Flow; RNA Interference; Time Factors; Transfection

Transplantation of the uterus has been suggested as a possible future treatment of absolute uterine infertility. The tolerability of human uterine tissue to cold ischaemic storage was tested in the present study.. Small tissue samples of human uteri were subjected to cold (4 degrees C) ischaemia (6 and 24 h) in Ringer acetate (RIN), the intracellular-like University of Wisconsin solution (UW) or the extracellular-like Perfadex solution (PER). The ability of myometrial strips to contract, histology by light and electron microscopy as well as tissue concentrations of glutathione, ATP and protein were used as parameters to detect cold ischaemic injuries.. Contractile ability and response to prostaglandin F(2alpha) (PGF(2alpha)) was better preserved after 6 h cold ischaemia in UW and PER in comparison with the other groups. Histological examination did not reveal any major changes after 6 and 24 h cold ischaemic storage in UW and PER solutions, while specimens stored in RIN for 24 h displayed degenerative changes on the electron microscopy level. UW and PER preserved ATP concentrations significantly better than RIN. Myometrium stored in UW contained more total glutathione but also a larger proportion of oxidized glutathione than specimens stored in RIN and PER. Protein concentrations did not change with storage time in any of the solutions.. The results show that human uterine myometrial tissue is resistant towards cold ischaemia for at least 6 h if stored in UW and PER solutions.

Topics: Adenosine; Adenosine Triphosphate; Adult; Allopurinol; Citrates; Cold Temperature; Cryopreservation; Dinoprost; Female; Glutathione; Humans; Insulin; Ischemia; Isotonic Solutions; Microscopy, Electron; Middle Aged; Muscle Contraction; Myometrium; Organ Preservation; Organ Preservation Solutions; Organ Transplantation; Premenopause; Raffinose; Reperfusion; Specimen Handling; Temperature; Time Factors; Uterine Contraction; Uterus

The detrimental role of oxidative stress has been widely described in tissue damage caused by ischemia-reperfusion. A nonenzymatic, reactive oxygen species-related pathway has been suggested to produce 8-iso-prostaglandin F(2alpha) (8-iso-PGF(2alpha)), an epimer of prostaglandin F(2alpha) (PGF(2alpha)), which has been proposed as an indicator of oxidative stress. Using an in vivo ischemia-reperfusion model in rat kidneys, we investigated intrarenal accumulation of 8-iso-PGF(2alpha) and PGF(2alpha). Both prostanoids accumulated in the ischemic kidney and disappeared upon reperfusion. In addition, a nonselective (acetylsalicylic acid) or selective cyclooxygenase (COX) 1 inhibitor (SC-560) completely abrogated the 8-iso-PGF(2alpha) and PGF(2alpha) formation in kidneys subjected to ischemia. COX2 inhibition had no effect on the production of these prostanoids. Therefore the two metabolites of arachidonic acid seemed to be produced via an enzymatic COX1-dependent pathway. Neither COX overexpression nor COX activation was detected. We also investigated renal glutathione, which is considered to be the major thiol-disulfide redox buffer of the tissue. Total and oxidized glutathione was decreased during the ischemic period, whereas no further decrease was seen for up to 60 min of reperfusion. These data demonstrate that a dramatic decrease in antioxidant defense was initiated during warm renal ischemia, whereas the 8-iso-PGF(2alpha) was related only to arachidonate conversion by COX1.

Topics: Animals; Arachidonic Acid; Cyclooxygenase 1; Dinoprost; Enzyme Inhibitors; F2-Isoprostanes; Free Radicals; Gas Chromatography-Mass Spectrometry; Glutathione; Ischemia; Isoenzymes; Kidney; Kinetics; Male; Membrane Proteins; Oxidation-Reduction; Oxidative Stress; Prostaglandin-Endoperoxide Synthases; Pyrazoles; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Reperfusion Injury; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Time Factors

8-Isoprostaglandin F2alpha is one of a series of isoprostanes formed by free radical catalysed peroxidation of arachidonic acid. Urinary 8-isoprostaglandin F2alpha is a new marker which reflects oxidative stress in vivo and can be utilized as a diagnostic tool to assess the extent of oxidative stress in various disease states associated with lipid peroxidation. Increased levels of 8-isoprostaglandin F2alpha in cardiac ischemia/reperfusion provide evidence for oxidative stress during coronary perfusion. In animal studies, the restoration of blood flow after lower limb ischemia is followed by reperfusion syndrome. In this study we investigated whether lower limb ischemia/reperfusion is associated with oxidative stress, as reflected by urinary levels of 8-isoprostaglandin F2alpha. Ten patients (mean age 72 years, range 61-82 years) suffering from chronic lower limb ischemia and 10 healthy volunteers (mean age 69 years, range 60-79 years) participated in the study. In all patients, diagnostic angiography had revealed stenosis or occlusion either in the aortoiliac or femoropopliteal region. Surgical revascularization consisted of femoropopliteal reconstruction, femorofemoral reconstruction, aortobifemorial reconstruction, or femoral endartectomy. Urine samples from patients were collected a day before surgery and in the second postoperative day. Urinary 8-isoprostaglandin F2alpha was extracted on a C2 silica cartridge and determinated by radioimmunoassay. After revascularization, 8-isoprostaglandin F2alpha excretion (pg/micromol creatinine, mean +/- SD) was decreased by 2.5-fold (preoperative 48.9 +/- 8.9, postoperative 19.1 +/- 9.5, P < 0.001). The postoperative values were similar to the concentrations measured in healthy volunteers (18.0 +/- 11.0). All revascularizations were successful, and the increase in ankle-brachial index (preoperative 0-0.6, postoperative 0.4-0.8) revealed improved blood flow in the ischemic lower limb. We suggest that, as assessed by the quantitation of urinary 8-isoprostaglandin F2alpha, chronic lower limb ischemia is associated with increased oxidative stress, which is decreased by revascularization.

Topics: Aged; Aged, 80 and over; Chronic Disease; Dinoprost; Female; Free Radical Scavengers; Humans; Ischemia; Lower Extremity; Male; Middle Aged; Myocardial Revascularization; Oxidative Stress; Radioimmunoassay

Free radicals are believed to be involved in postsurgery-related complications. We studied whether cardiopulmonary bypass (CPB) operation has any immediate impact on the initiation of oxidative stress and inflammatory response by measuring isoprostanes and prostaglandin F2alpha during and 24 h following CPB. The levels of 8-iso-PGF2alpha (a major F2-isoprostane and biomarker of oxidative stress) and 15-keto-dihydro-PGF2alpha (a major metabolite of PGF2alpha and biomarker of inflammatory response) were measured in frequently collected plasma samples before, during, and up to 24 h postsurgery in 21 patients. 8-Iso-PGF2alpha levels significantly increased within 3 min (p <.0001) and continued until 50 min (p <.0001) during CPB. On the contrary, no significant increase of inflammatory response indicator, 15-keto-dihydro-PGF2alpha was found during and up to 24 h postoperatively. These findings establish an increased free radical-induced oxidative stress activity rather than inflammatory response after CPB.

Topics: Adult; Aged; Cardiopulmonary Bypass; Dinoprost; Female; Free Radicals; Humans; Inflammation; Ischemia; Isoprostanes; Male; Middle Aged; Models, Chemical; Oxidative Stress; Oxygen; Prostaglandins; Radioimmunoassay; Time Factors

Membrane phospholipid breakdown, caused by ischemia and reperfusion (I/R) of the liver, releases free fatty acids including arachidonic acids and lysophospholipids, which serve as precursors of various inflammatory lipid derivatives. Phospholipase A2 (PLA2) is a key enzyme that initiates this reaction. In this study, we tested our hypothesis that a type II PLA2 inhibitor, LY329722, could attenuate hepatic I/R injury caused by a 2-hr total hepatic vascular exclusion (THVE) in dogs.. Eighteen beagle dogs, subjected to a 2-hr THVE, were divided into three groups. Group 1 (n=6) was untreated and served as a control group. LY329722 was administered to animals in group 2 (n=6) intravenously (0.2 mg x kg(-1) x hr(-1)) for 60 min before ischemia, and to animals in group 3 (n=6) for 60 min starting 15 min before reperfusion (0.2 mg x kg(-1) x hr(-1)). Animal survival, systemic and splanchnic hemodynamics, hepatic tissue blood flow, liver functions, energy metabolism, hepatic venous thromboxane B2 and endothelin-1 levels, phospholipid levels and tumor necrosis factor-a mRNA expression in liver tissue, and histopathologic findings were evaluated.. Two-week animal survival was 33% (two of six) in group 1, and 100% (six of six) in groups 2 and 3. LY329722 improved systemic and splanchnic hemodynamics, hepatic tissue blood flow, and energy metabolism, reduced liver enzyme, thromboxane B2, and endothelin-1 release, prevented hepatic phospholipid degradation and tumor necrosis factor-alpha mRNA expression, and lessened histopathologic damage and the number of neutrophil infiltrating into the liver tissue.. The present study demonstrated that a type II PLA2 inhibitor, LY329722, attenuated hepatic I/R injury caused by a 2-hr THVE model in dogs.

Topics: Acetates; Animals; Dinoprost; Dogs; Endothelin-1; Energy Metabolism; Enzyme Inhibitors; Female; Hemodynamics; Indoles; Ischemia; Liver; Liver Circulation; Liver Function Tests; Phospholipases A; Phospholipases A2; Regional Blood Flow; Reperfusion Injury; Splanchnic Circulation; Thromboxane B2; Time Factors; Transcription, Genetic; Tumor Necrosis Factor-alpha

Despite increasing evidence supporting the involvement of neutrophils in ischemic and postischemic damages, the mechanisms underlying the early recruitment of these cells are not completely understood. In this report, the effects of conditioned media from hypoxic endothelial cells on neutrophil chemotaxis were investigated by biochemical and morphological studies. We showed that conditioned media collected from several endothelial cell origins submitted to hypoxia as well as ischemic rat liver perfusion liquids have a chemotactic activity for neutrophils. The role of various chemoattractant molecules like HETEs, platelet-activating factor, and cytokines such as interleukin-8 and interleukin-1 was examined in the same model. Chemotactic peptide contribution was ruled out as boiled conditioned media still trigger chemotaxis. However, cell treatment with cyclooxygenase inhibitors, neutralization of PGF(2alpha) biological activity with polyclonal antibodies, and the neutrophil preincubation with a specific PGF(2alpha) antagonist, all dramatically inhibited neutrophil chemotaxis. A strong chemoattractant effect of pure exogenous PGF(2alpha) or of a synthetic analog was also observed. The major effect of PGF(2alpha) on neutrophil chemotaxis was confirmed ex vivo in a rat liver perfusion ischemic model. These results suggest that PGF(2alpha), a prostanoid abundantly released by the endothelium of hypoxic or ischemic tissues, is a chemoattractant molecule that might be involved in the early recruitment of neutrophils in ischemic organs.

Topics: Animals; Cells, Cultured; Chemotactic Factors; Culture Media, Conditioned; Dinoprost; Endothelium, Vascular; Female; Humans; Hydroxyeicosatetraenoic Acids; Hypoxia; Interleukin-1; Interleukin-8; Ischemia; Liver Circulation; Neutrophil Infiltration; Prostaglandin Antagonists; Prostaglandins F; Rats; Rats, Wistar

Endothelial cell injury after hemorrhage and resuscitation (HEM/RES) might contribute to intestinal hypoperfusion and mucosal ischemia. Our recent work suggests that the injury might be the result of complement activation. We hypothesized that HEM/RES causes complement-mediated endothelial cell dysfunction in the small intestine.. Male Sprague-Dawley rats (195-230 g) were anesthetized and HEM to 50% of baseline mean arterial pressure for 60 minutes. Just before RES, animals received either soluble complement receptor-1 (sCR1, 15 mg/kg) to inhibit complement activation or saline vehicle. Resuscitation was with shed blood and an equal volume of saline. Two hours after RES, the small bowel was harvested to evaluate intestinal nitric oxide synthase activity (NOS), neutrophil influx, histology, and oxidant injury.. HEM/RES induced tissue injury, increased neutrophil influx, and reduced NOS activity by 50% (vs. SHAM), all of which were completely prevented by sCR1 administration. There were no observed differences in oxidant injury between the groups.. Histologic tissue injury, increased neutrophil influx, and impaired NOS activity after HEM/RES were all prevented by complement inhibition. Direct oxidant injury did not seem to be a major contributor to these alterations. Complement inhibition after HEM might ameliorate reperfusion injury in the small intestine by protecting the endothelial cell, reducing neutrophil influx and preserving NOS function.

Topics: Animals; Complement Activation; Dinoprost; Disease Models, Animal; Intestinal Mucosa; Ischemia; Linear Models; Male; Neutrophil Activation; Nitric Oxide Synthase; Peroxidase; Rats; Rats, Sprague-Dawley; Resuscitation; Shock, Hemorrhagic

Ruptured abdominal aortic aneurysm (RAAA) remains a lethal condition despite improvements in perioperative care. The consequences of RAAA are hypothesized to result from a combination of two ischemia/reperfusion events: hemorrhagic shock and lower torso ischemia. Ischemia/reperfusion results in tissue injury by diverse mechanisms, which include oxygen free radical-mediated injury produced from activated neutrophils, xanthine oxidase, and mitochondria. Oxygen-free radicals attack membrane lipids, resulting in membrane and subsequently cellular dysfunction that contributes to postoperative organ injury/failure. The purpose of this investigation was to quantify the oxidative injury that occurs as a result of the ischemia/reperfusion events in RAAAs and elective AAAs.. Blood samples were taken from 22 patients for elective AAA repair and from 14 patients for RAAA repair during the perioperative period. Plasma F(2)-isoprostanes were extracted, purified, and measured with an enzyme immunoassay. Aldehydes and acyloins were purified and quantified. Neutrophil oxidative burst was measured in response to a receptor independent stimulus (phorbol 12-myristate 13-acetate) with luminol-based chemiluminescence.. Plasma from patients with RAAAs showed significantly elevated F(2)-isoprostane levels on arrival at hospital and were significantly elevated as compared with the levels of patients for elective repair throughout the perioperative period (two-way analysis of variance, P <.0001). Multiple regression showed a significant relationship between the phagocyte oxidative activity and F(2)-isoprostane levels (P <.013). Total acyloin levels were significantly higher in patients with RAAAs as compared with the levels in elective cases.. The F(2)-isoprostane levels, specific markers of lipid peroxidation, showed that patients with RAAAs had two phases of oxidative injury: before arrival at hospital and after surgery. The significant relationship between the postoperative increases in F(2)-isoprostane levels and the neutrophil oxidant production implicates neutrophils in the oxidative injury that occurs after RAAA. New therapeutic interventions that attenuate neutrophil-mediated oxidant injury during reperfusion may decrease organ failure and ultimately mortality in patients with RAAAs.

Topics: Aldehydes; Aneurysm, Ruptured; Aortic Aneurysm, Abdominal; Biomarkers; Dinoprost; Fatty Alcohols; Humans; In Vitro Techniques; Ischemia; Luminescent Measurements; Models, Cardiovascular; Neutrophils; Oxidative Stress; Reperfusion Injury; Respiratory Burst; Shock, Hemorrhagic; Tetradecanoylphorbol Acetate

Pulmonary edema develops when pulmonary blood flow is interrupted, then restored. Because the lung is not always hypoxic when ischemic, mechanisms of pulmonary ischemia-reperfusion injury are likely to differ from systemic organs, where reactive oxygen species generated during reperfusion mediate organ dysfunction. We previously showed that pulmonary vascular permeability of isolated ferret lungs increased prior to reperfusion, if ventilation was maintained while blood flow was impaired. To determine whether reactive oxygen metabolites generated during ischemia mediated ischemic injury, we measured tissue levels of F2-isoprostanes as an index of lipid peroxidation, 30 min after administration of glucose (5 mM)-glucose oxidase (GOX, 0.1 U/ml), or after short (45 min) or long (180 min) ventilated ischemia, in isolated ferret lungs. Osmotic reflection coefficient for albumin (sigma alb), an estimate of vascular protein permeability, was measured in the same lungs. Tissue F2-isoprostanes increased 375% after exposure to glucose-GOX in association with a 42% decrease in sigma alb, and administration of catalase (CAT, 100,000 U) and superoxide dismutase (SOD, 25,000 U) completely attenuated this lipid peroxidation. In contrast, tissue F2-isoprostanes increased only 60% following 45 min of ischemia, then did not increase additionally. sigma alb was not altered by 45 min of ischemia, but decreased 72% following 180 min of ischemia. CAT+SOD did not alter F2-isoprostane formation during ischemia, but partially attenuated vascular injury. These results suggest that tissue levels of F2-isoprostanes reflect lung lipid peroxidation, but that F2-isoprostane generation does not directly increase vascular permeability following ventilated pulmonary ischemia.

Topics: Animals; Antioxidants; Capillary Permeability; Catalase; Cyclic N-Oxides; Dinoprost; Electron Spin Resonance Spectroscopy; Ferrets; Glucose; Glucose Oxidase; Ischemia; Lung; Mass Spectrometry; Oxidants; Reactive Oxygen Species

The involvement of prostaglandins (PGs) in the development of anterior segment ischaemia after occlusion of the bilateral long posterior ciliary arteries was investigated in rabbit eyes. In this experimental ischaemia, the tissue weight and protein content in the peripheral cornea and the protein content in the aqueous humour increased on the first postoperative day. Topically applied cyclooxygenase inhibitor diclofenac (0.1%) reduced corneal inflammation and further suppressed the elevation in the tissue weight and protein content in the peripheral cornea on day 1 after ischaemia, but did not affect the changes in the aqueous humour. Subconjunctivally administered PGE1 and PGE2 induced corneal oedema and increased corneal protein content in diclofenac-treated and ischaemia-induced eyes, but PGD2, PGF2alpha, and the stable PGI2 analogue cicaprost did not evoke any change. In fact, PGE2 content was markedly increased in the aqueous humour on day 1 after ischaemia, and diclofenac suppressed the increase. In addition, CPT-cAMP increased the corneal tissue weight and protein content in organ culture. These observations suggest that PGE2 may play an important role in developing corneal oedema at the initial stage of ischaemic damage, possibly through the cAMP-mediated pathway.

Topics: Alprostadil; Animals; Anterior Eye Segment; Aqueous Humor; Cornea; Corneal Diseases; Corneal Edema; Cyclic AMP; Cyclooxygenase Inhibitors; Diclofenac; Dinoprost; Dinoprostone; Ischemia; Male; Organ Culture Techniques; Prostaglandins; Proteins; Rabbits

Many vasoactive substances induce two responses, a direct effect at the site of application and a conducted response that spreads along the vessel length. In the microcirculation, we find that these two components of the vasomotor response display quite different sensitivities to occlusion and/or ischemia. Conducted vasomotor responses were induced in arterioles of the hamster cheek pouch by micropipette application of two test agents: phenylephrine (PE), which causes a receptor-mediated vasomotor response, and KCl, which causes an alteration in the membrane potential by a simple change in the K+ gradient. Ischemia was produced either by total occlusion of the vascular supply, which resulted in a complete cessation of flow in all vessels, or by venous occlusion, which was achieved by gradually inflating a pressurized cuff positioned across the pedicle of the pouch until venous return from the pouch was arrested while the feed arterioles remained patent. Both types of occlusion produced ischemia, the former with low intravascular pressure, the latter with high intravascular pressure. During both types of occlusion, arterioles were initially maximally dilated and unresponsive to both agonists, but over a subsequent 3- to 5-min period, resting arteriolar tone and local responses to both agonists returned. With total occlusion, the conducted response to KCl returned in parallel with the local response, whereas the conducted response to PE was diminished or absent. With venous occlusion, the local responses recovered as with total occlusion, but the conducted responses to both PE and KCl recovered as well.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Arterioles; Biomechanical Phenomena; Cheek; Cricetinae; Dinoprost; Electrophysiology; Ischemia; Male; Mesocricetus; Phenylephrine; Potassium Chloride; Vasomotor System

The pathophysiological importance of reactive oxygen species has been extensively documented in the pathogenesis of hepatic ischemia-reperfusion injury. Kupffer cells and neutrophils were identified as the dominant sources of the postischemic oxidant stress. To test the hypothesis that a direct free radical-mediated injury mechanism (lipid peroxidation; LPO) may be involved in the pathogenesis, highly sensitive and specific parameters of LPO, i.e., hydroxy-eicosatetraenoic acids (HETES), and F2-isoprostanes, were determined by gas chromatographic-mass spectrometric analysis in liver tissue and plasma during 45 min of hepatic ischemia and up to 24 h of reperfusion. A significant 60-250% increase of F2-isoprostane levels in plasma was found at all times during reperfusion; the HETE content increased only significantly at 1 h of reperfusion and in severely necrotic liver tissue at 24 h with increases between 90-320%. On the other hand, in a model of LPO-induced liver injury (infusion of 0.8 mumol tert-butylhydroperoxide/min/g liver), the hepatic HETE content increased two to fourfold over baseline values at 45 min, i.e., before liver injury. A further increase to 12- to 30-fold of baseline was observed during moderate liver injury. Based on these quantitative comparisons of LPO and liver injury, it seems highly unlikely that LPO is the primary mechanism of parenchymal cell injury during reperfusion, although it cannot be excluded that LPO may be important as a damaging mechanism in a limited compartment of the liver, e.g., endothelial cells, close to the sources of reactive oxygen, e.g., Kupffer cells and neutrophils.

Topics: Alanine Transaminase; Analysis of Variance; Animals; Dinoprost; Gas Chromatography-Mass Spectrometry; Glutathione; Glutathione Disulfide; Ischemia; Lipid Peroxidation; Liver; Male; Peroxides; Rats; Rats, Inbred F344; Reactive Oxygen Species; Reperfusion; tert-Butylhydroperoxide; Time Factors

The effect of PGE1 and PGF2 alpha in the ischemic intestinal tract were examined. In 40 mongrel dogs, we studied ischemic models of small intestine. PGE1 or PGF2 alpha was injected into the anterior mesenteric artery after reperfusion according to each occlusion time, and the tissue blood flow was measured on both mucosal and serous sides of small intestinal loop by laser flowmeter to examine the relation to the extent of tissue damage. Tissue blood flow of the ischemic intestine after the injection of PGE1 increased by 148-208% in the 3-5 hr occlusion group and by 86-110% in the 7-10 hr occlusion group. Tissue blood flow after the injection of PGF2 alpha decreased by 39-59% in the 3-5 hr occlusion group and by 1-15% in the 7-10 hr occlusion group. These results indicate that the effect of PGE1 and PGF2 alpha in the ischemic intestine would be available up to 3-5 hr of ischemia. Histological examination revealed that viability of the remaining crypt was high in the PGE1 injection group but low in the PGF2 alpha injection group. These findings suggest that PGE1, if try at the early stage, would be effective for the treatment of ischemic lesion.

Topics: Alprostadil; Animals; Dinoprost; Dogs; Intestinal Mucosa; Intestine, Small; Ischemia; Laser-Doppler Flowmetry; Regional Blood Flow

The role of PGF2 alpha in circulatory shock of intestinal origin was investigated in anesthetized dogs by measuring PGF2 alpha levels in superior mesenteric vein, right ventricle, aorta, and femoral vein during superior mesenteric artery occlusion-induced shock by comparing the circulatory effects of exogenous PGF2 alpha injected into either the superior mesenteric or the femoral vein and by inhibiting of prostanoid synthesis with indomethacin. Release of the superior mesenteric artery occlusion caused a dramatic decrease in mean arterial blood pressure; an increase in mean portal venous pressure, and more than fivefold increases in plasma PGF2 alpha levels in superior mesenteric vein, right ventricle, and aorta. In spite of the decreased mean arterial blood pressure, postocclusion blood flow in the mesenteric artery did not fall below preocclusion values. Indomethacin in itself, significantly reduced plasma PGF2 alpha levels as well as intestinal blood flow and increased mean arterial blood pressure in animals without superior mesenteric artery occlusion. Furthermore, indomethacin attenuated the magnitude of postocclusion hypotension and completely prevented PGF2 alpha production during superior mesenteric artery occlusion shock. Exogenous PGF2 alpha 10 micrograms/kg injected into the superior mesenteric or femoral vein produced hypotension or hypertension, respectively. When PGF2 alpha was injected into the superior mesenteric vein, the plasma level of PGF2 alpha in the aorta was similar to that observed during superior mesenteric artery occlusion shock, whereas PGF2 alpha injected into the femoral vein gave a significantly higher concentration. Pulmonary metabolism of PGF2 alpha was significantly reduced in shock. The present results suggest that PGF2 alpha released by intestinal tissues might play an important role in shock caused by intestinal ischemia.

Topics: Animals; Blood Pressure; Dinoprost; Dogs; Hemodynamics; Indomethacin; Intestinal Mucosa; Intestines; Ischemia; Mesenteric Arteries; Mesenteric Vascular Occlusion; Shock

A new experimental model for studying the effects of acute ischemia on brain development in the near-term fetal rat has been devised. Ischemic conditions are achieved by complete clamping of blood vessels branching from the uterine vasculature into each individual fetus for designated times followed by removal of the clamps to permit reperfusion. Accumulation of lactic acid in the fetal brain depends on the length of the restriction period, reaching a plateau level of 29 mumol/g tissue at about 30 min. It also depends on the reperfusion time. Thus after a period of 15 min of restriction lactate levels show an increase over the next 30-min reperfusion to a value of 25.5 mumol/g followed by a rapid decrease to normal values by 3 h of reperfusion. Restriction of 15 min followed by reperfusion of 45 min causes an elevation of prostaglandin E2 (PGE2) level from 12.4 +/- 0.86 ng/g to 21.1 +/- 0.6 ng/g (p less than 0.001). This elevation in PGE2 level is less apparent after 20 min of restriction. No effects are seen on the level of PGF2 alpha. Both PGE2 and PGF2 alpha accumulate in vitro in a time-dependent manner by brain particulate fraction. In vitro synthesis of both PGE2 and PGF2 alpha is inhibited by indomethacin (100% and 68%, respectively) and AA861 (94% and 76%, respectively). BW755c and nordihydroguaiaretic acid do not affect PGE2 formation but enhance PGF2 alpha production by 112% and 152%, respectively. Particulate fractions from restricted brain produce less PGF2 alpha than control brains (6.38 +/- 1.62 versus 11.43 +/- 2.2, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyrazol-3-amine; Animals; Benzoquinones; Brain; Cyclooxygenase Inhibitors; Dinoprost; Dinoprostone; Female; Indomethacin; Ischemia; Lactates; Lactic Acid; Lipoxygenase Inhibitors; Masoprocol; Placenta; Pregnancy; Prostaglandins; Prostaglandins E; Prostaglandins F; Pyrazoles; Quinones; Rats; Uterus

A pharmacological analysis was carried out to determine the possible role of aberrant calcium fluxes, vasoactive arachidonic acid metabolites, and microvascular lipid peroxidation in the development of posttraumatic spinal cord white matter ischemia. Pentobarbital-anesthetized cats were treated intravenously 30 minutes before a 500-gm-cm contusion injury to the lumbar spinal cord with one of the following test drugs: the Ca++ channel antagonists verapamil, diltiazem, or nifedipine; the cyclo-oxygenase inhibitors ibuprofen or meclofenamate; the thromboxane A2 (TXA2) synthetase inhibitor furegrelate sodium; or the stable epoprostenol (prostacyclin, or PGI2) analogue ciprostene calcium alone or in combination with furegrelate sodium. Another group of animals was pretreated for 5 days before spinal injury with a combination of the antioxidants vitamin E and selenium in high doses. The hydrogen clearance technique was used to make repeated measurements of spinal cord blood flow (SCBF) in the dorsolateral funiculus of the injured segment before and for 4 hours after injury. In 11 untreated uninjured cats, the mean preinjury SCBF was 12.7 +/- 1.5 ml/100 gm/min. Following contusion, there was a progressive decline in SCBF to 6.8 +/- 0.4 ml/100 gm/min, or 53.5% of the preinjury level at 4 hours. In comparison, the Ca++ antagonists diltiazem and nifedipine (but not verapamil) prevented a significant posttraumatic decrease in SCBF. Similarly, both cyclo-oxygenase inhibitors (ibuprofen and meclofenamate) maintained SCBF within normal limits (10 ml/100 gm/min or greater). However, neither TXA2 synthetase inhibition nor the stable PGI2 analogue alone had a significant effect in preventing ischemia, whereas a combination of the two agents did serve to support SCBF. The most impressive preservation of posttraumatic SCBF, however, was observed in the antioxidant-treated animals. Based upon these results, a hypothesis is presented concerning the pathogenesis of posttraumatic central nervous system ischemia which integrates an injury-induced rise in intracellular Ca++, the increased synthesis of vasoactive prostanoids (such as prostaglandin F2 alpha and TXA2), and progressive microvascular lipid peroxidation.

Topics: Animals; Benzofurans; Calcium Channel Blockers; Cats; Cyclooxygenase Inhibitors; Diltiazem; Dinoprost; Epoprostenol; Female; Ibuprofen; Ischemia; Male; Meclofenamic Acid; Nifedipine; Prostaglandin Antagonists; Prostaglandins F; Spinal Cord; Thromboxane A2; Verapamil; Vitamin E