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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The formation of new blood vessel is essential for a variety of physiological processes like embryogenesis and the female reproduction as well as wound healing and neovascularization of ischemic tissue. Major progress in understanding the underlying mechanisms regulating blood vessel growth has offered novel therapeutic options in the treatment of a variety of diseases including ischemic cardiovascular disorders. Vasculogenesis and angiogenesis are the mechanisms responsible for the development of the blood vessels. Angiogenesis refers to the formation of capillaries from preexisting vessels in the embryo and adult organism. While pathologic angiogenesis includes the role of post-natal neovascularization in the pathogenesis of arthritis, diabetic retinopathy, and tumor growth and metastasis, therapeutic angiogenesis, either endogenously or in response to administered growth factors, includes the development of collateral blood vessels in tissue ischemia. Preclinical studies established that angiogenic growth factors could promote collateral artery development in animal models of peripheral and myocardial ischemia. Subsequent clinical trials using gene transfer of naked DNA encoding for VEGF for the treatment of critical limb and myocardial ischemia documented the safety and clinical benefit of this novel therapeutic approach. Several objective methods indicated marked improvement in collateral vessel development. Vasculogenesis describes the development of new blood vessels from in situ differentiating endothelial cells. Recently considered to be restricted to embryogenesis, there exists now striking evidence that endothelial progenitor cells (EPC) circulate also in adult peripheral blood able to participate in ongoing neovascularization. Different cytokines and growth factors have a stimulatory effect on these bone-marrow derived EPC. Granulocyte macrophage colony stimulating factor (GM-CSF) and vascular endothelial growth factor (VEGF) mobilize EPC from the bone marrow into the peripheral circulation. While their endogenous contribution to postnatal neovascularization needs to be documented, the iatrogenic expansion and mobilization of EPC might represent an effective means to augment the resident population of endothelial cells (ECs). This kind of cell therapy for tissue regeneration in ischemic cardiovascular diseases opens a novel and challenging clinical option besides or in addition to the use of growth factors in gene therapy.
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PMID:[Angiogenesis and vasculogenesis. Therapeutic strategies for stimulation of postnatal neovascularization]. 1107 19

The response of tumor necrosis factor alpha (TNF alpha), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), interleukin-1 receptor antagonist (IL-1ra), macrophage colony stimulating factor (MCSF), white blood cell (WBC), platelet (Plt), lactic acid (LAC) to cardiopulmnary bypass (CPB) were studied until 48 hours after aortic declamping in 11 patients who underwent elective CABG (n = 4), mitral valve plasty or replacement with modified maze procedure (n = 5), and both procedures (n = 2). The highest levels of the cytokines IL-6, IL-8, IL-10, and IL-1ra were observed after the removal of the cross clamp. These cytokines just after the aortic declamping are likely to be occurred not only by an interaction of the blood components with the artificial surfaces, but also by ischemia-reperfusion injury upon discontinuation of the aortic clamping. MCSF increased gradually in the late post-CPB phase and reached a peak at 48 hr after aortic declamping. MCSF may play an important role in regulating hematopoiesis on the postoperative days 1 and 2 in patients. In conclusion, the therapy based on the kinetics of these cytokines would be useful for patients undergoing CPB.
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PMID:[Serum cytokine levels response to cardiac surgery with cardiopulmonary bypass]. 1145 22

This article is a review of our experimental results regarding the physiological statuses and roles of chemical mediators in tourniquet shock, and a novel phenomenon, modulation reflex, that is commonly observed in this shock model is discussed. In a rabbit with a tourniquet applied to a hind limb for 24 hrs, blood pressure (BP) gradually falls after release of the tourniquet, but the decline in BP stops when a tourniquet is again applied to the hind limb, indicating that shock mediators are attributed to the hind limb. The levels of dipeptides (anserine and carnosine) and lysosomes in blood samples as well as the levels of leukotrienes (LTD4 and LTE4) in blood and muscle samples from rabbits in tourniquet shock were elevated. However, injection of a large amount of a dipeptide into an ear vein of a rabbit did not reduce BP, suggesting that both peptides may not be directly related with reduction in BP of rabbits in tourniquet shock. Injection of a platelet-activating factor (PAF) antagonist into an ear vein resulted in slight elevation of BP and the elevated level was maintained for about 1 to 4 hrs during the period of decline in BP in tourniquet shock. As for interleukin-6 (IL-6), IL-6-deficient mice at young ages have a significantly greater blood volume than do wild-type mice without concomitant changes in body composition. Therefore, the role for IL-6 in the regulation of peripheral circulation may be to elevate, not reduce BP. In mice in tourniquet shock, superoxide (O2-) production is observed in skeletal muscle cells and these cells correspond to mitochondria-rich cells. However, RT-PCR of muscle samples showed no significant nitric oxide synthase (NOS) mRNA expression after tourniquet release. Pretreatment with NOS inhibitors before tourniquet release reduced O2- production in the skeletal muscle. These results indicate that O2- produced in muscle subjected to ischemia/repefusion may be involved in shock. As for changes in mRNA expression patterns of pro-inflammatory cytokines and nerve growth factors in blood samples from rats in tourniquet shock, up-regulation of M-CSF mRNA began at 2 h after tourniquet application and was short-lived. The level of ATF-3 mRNA had increased at 1 h and NGF mRNA gradually increased and reached a significantly high level at 4 h after tourniquet application. These results indicate that the transient mRNA expressions probably trigger secondary events that may be beneficial to wound repair and regeneration. In the early stage of tourniquet shock, the levels of IL-6 mRNA in the liver and kidneys of rats increased progressively and significantly, and the levels of iNOS mRNA in the kidneys increased. These findings suggest that that humoral and/or cellular mediators produced locally in the hind limb are responsible for remote organ injuries. Thus, these mediators, interacting each other, may contribute to the progress of shock. We have also found a novel phenomenon in tourniquet shock using rabbits. When a tourniquet is applied to the upper hind limb of a rabbit for 24 hrs, and pressure is applied to the femoral medial area immediately after tourniquet release, a reflex of decrease in blood pressure and decrease in heart rate, which last for a short period, is usually observed. This reflex is mediated through the ipsilateral femoral nerves, central nervous system and vagal nerves. Since the modulation reflex may be due to peripheral nerve injury, we investigated morphological and molecular changes in sciatic nerves and dorsal root ganglion (DRG) neurons in rats after tourniquet application. At 4 hr after tourniquet application, light microscopic examination showed only degeneration of the tourniquet segment in the sciatic nerve but no morphological changes in the DRG, while electron microscopic examination revealed mitochondrial swelling in some DRG neurons on the tourniquet-applied side and calcium deposition in these swollen mitochondria. These findings suggest that peripheral nerve injury induced a large amount of calcium influx into neuronal cell somas and that excess amounts of calcium-influx into neurons resulted in mitochondial swelling. Results of mRNA level analyses showed NGF mRNA expression followed by NGF protein expression in Schwann cells of the ipsilateral DRGs at 4 h after tourniquet application but not in the contralateral or control DRGs. Similarly, significantly high nNOS and iNOS mRNA levels were observed in the ipsilateral DRGs at 4 h, and expressions of nNOS and iNOS proteins were detected in the ganglion of the ipsilateral DRG. In addition, the TNF-alpha mRNA levels were significantly increased in the ipsilateral DRGs at 1 h after tourniquet application, indicating that TNF-alpha was activated in the early stage of nerve injury and then induced iNOS mRNA expression. Large amounts of nitric oxide (NO) produced by iNOS might result in damage to the host cells, and an overdose of NO might induce apoptosis and eliminate damaged cells during the early stage of nerve injury.
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PMID:[Novel findings from an animal tourniquet shock model]. 1457 64

Ischemic acute renal failure involves not only the kidney but also extrarenal organs such as the bone marrow that produces inflammatory cells. By ELISA and RNase protection assays, we now show that renal ischemia-reperfusion increases serum concentrations of granulocyte macrophage colony-stimulating factor (G-CSF) protein and increases both G-CSF mRNA and protein in the ischemic kidney. In situ hybridization localized the increased G-CSF mRNA to tubule cells, including medullary thick ascending limb cells (mTAL), in the outer medulla. We also show that mTAL produce G-CSF protein and increase G-CSF mRNA after stimulation by reactive oxygen species in vitro. The production of G-CSF by the kidney after ischemia-reperfusion provides a means of communication from the injured kidney to the bone marrow. This supports the known inflammatory response to ischemia.
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PMID:Ischemia-reperfusion induces G-CSF gene expression by renal medullary thick ascending limb cells in vivo and in vitro. 1473 60

Inflammatory processes play a crucial role in the pathogenesis of atherosclerosis and other vascular disorders. We hypothesized that ischemia of the ductus arteriosus might initiate an active inflammatory response that could play a role in ductus remodeling and permanent closure. To test this hypothesis, we studied effects of postnatal ductus construction on inflammatory processes and remodeling in late-gestation fetal and newborn baboons, and preterm newborn baboons. After postnatal ductus constriction, the expression of several genes known to be essential for atherosclerotic remodeling [vascular cell adhesion molecule (VCAM)-1, E-selectin, IL-8, macrophage colony stimulating factor-1, CD154, interferon-gamma, IL-6, and tumor necrosis factor-alpha] was increased in the ductus wall. We were unable to detect intercellular adhesion molecule (ICAM)-1, ICAM-2, P-selectin, monocyte chemoattractant protein-1, or IL-1 by either real-time PCR or immunohistochemistry. VCAM-1, which is newly expressed by luminal cells of the closed ductus, is an important ligand for the mononuclear cell adhesion receptor VLA4. After postnatal constriction, VLA4+ monocytes/macrophages (CD68+ and CD14+) and, to a lesser extent, T-lymphocytes adhered to the ductus wall. Neutrophils and platelets were not observed. The extent of postnatal neointimal remodeling (both endothelial cell layering and subendothelial space thickening) was associated with the degree of mononuclear cell adhesion. Similarly, the extent of vasa vasorum ingrowth correlated with the invasion of CD68+ cells, from the adventitia into the muscle media. Based on these data, we conclude that the inflammatory response following postnatal ductus constriction may be as necessary for ductus remodeling as it is for atherosclerotic remodeling.
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PMID:The role of monocyte-derived cells and inflammation in baboon ductus arteriosus remodeling. 1561 59

Versican, a large chondroitin sulfate proteoglycan, plays a role in conditions such as wound healing and tissue remodelling. To test the hypothesis that versican expression is transiently upregulated and plays a role in the infarcted heart, we examined its expression in a rat model of myocardial infarction. Northern blot analysis demonstrated increased expression of versican mRNA. Quantitative real-time RT-PCR analysis revealed that versican mRNA began to increase as early as 6 h and reached its maximal level 2 days after coronary artery ligation. Versican mRNA then gradually decreased, while the mRNA of decorin, another small proteoglycan, increased thereafter. Versican mRNA was localized in monocytes, as indicated by CD68-positive staining, around the infarct tissue. The induction of versican mRNA was accelerated by ischemia/reperfusion (I/R), which was characterized by massive cell infiltration and enhanced inflammatory response. To examine the alteration of versican expression in monocytes/macrophages, we isolated human peripheral blood mononuclear cells and stimulated them with granulocyte/macrophage colony-stimulating factor (GM-CSF). Stimulation of mononuclear cells with GM-CSF increased the expression of versican mRNA as well as cytokine induction. The production of versican by monocytes in the infarct area represents a novel finding of the expression of an extracellular matrix gene by monocytes in the infarcted heart. We suggest that upregulation of versican in the infarcted myocardium may have a role in the inflammatory reaction, which mediates subsequent chemotaxis in the infarcted heart.
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PMID:Versican is induced in infiltrating monocytes in myocardial infarction. 1631 4

Recently we reported that macrophage colony-stimulating factor (M-CSF) can mobilize endothelial progenitor cells (EPCs) from the bone marrow into the peripheral blood, resulting in an increase in the number of blood vessels and augmentation of blood flow in the ischemia-induced legs. M-CSF accelerates neovascularization of ischemic lesions resulting from the mobilization of EPCs. In the present paper, we analyze the mechanisms underling the mobilization of EPCs by M-CSF. M-CSF augments the production of vascular endothelial growth factor (VEGF) from the bone marrow cells, especially from myeloid lineage cells. In vivo administration of anti-VEGF antibody abrogates both the acceleration of the recovery of blood flow in the ischemia-induced limbs by M-CSF and the augmentation of the mobilization of EPCs induced by M-CSF. These results suggest that the M-CSF contributes to rapid recovery of blood flow in ischemic lesions by mobilization of EPCs from the bone marrow through augmentation of VEGF production in the bone marrow and that the VEGF is mainly produced by myeloid lineage cells.
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PMID:Mechanisms underlying acceleration of blood flow recovery in ischemic limbs by macrophage colony-stimulating factor. 1645 35

Mitochondria play a central role in both the physiological and pathophysiological regulation of cell survival/death. Increasing evidence places mitochondrial dysfunction at the center of many neuropathological conditions. The present study investigates the extent of mitochondrial dysfunction in cortical, hippocampal and cerebellar tissues in a rat model of hypoxia-ischemia (HI). We hypothesized that; mitochondrial dysfunction in situ may be prevented by treatment with clomethiazole (CMZ), a GABA(A) receptor agonist. Assessment of mitochondrial FAD-linked respiration at both 1- and 3-day post-HI revealed a marked decrease in activity from ipsilateral cortical and hippocampal regions (P<0.001). In addition, small changes were seen in contralateral cortical and hippocampal tissues as well as in the cerebellum at 3-days (P<0.05). Assessment of the mitochondrial electron transport chain (complexes I-V), and mitochondrial markers of integrity (citrate synthase) and oxidative stress (aconitase) confirmed mitochondrial impairment in ipsilateral regions following HI. Complexes I, II-III, V and citrate synthase were also impaired in contralateral regions and cerebellum 3-days post-HI. Treatment with CMZ (414 mg/kg/day via minipumps) provided marked protection to all aspects of neuronal tissue assessed. Circulating cytokine (interleukin [IL]-1alpha, IL-1beta, tumor necrosis factor [TNF]-alpha, granulocyte macrophage colony-stimulating factor [GM-CSF], IL-4 and IL-10) levels were also assessed in these animals 3-days post-HI. Plasma IL-1alpha, IL-1beta, TNF-alpha and GM-CSF levels were significantly increased post-HI. Treatment with CMZ ameliorated the increases in IL-1alpha, IL-1beta, TNF-alpha and GM-CSF levels while increasing plasma IL-4 and IL-10 levels. This study provides evidence of the extent of mitochondrial damage following an HI-insult. In addition, we have shown that protection afforded by CMZ extends to preservation of mitochondrial function and integrity via anti-inflammatory mediated pathways.
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PMID:Mitochondrial involvement in transhemispheric diaschisis following hypoxia-ischemia: Clomethiazole-mediated amelioration. 1711 78

A multifunctional protein metallothionein (MT) is induced by various chemicals and cytokines. We have found novel functions of MT as follows: 1) Cytokine expression such as IL-1alpha, IL-6, and TNFalpha responding to lipopolysaccharide is reduced in MT-deficient macrophages compared with in wild-type cells. 2) Nitric oxide production responding to TNFalpha and LPS is reduced in MT-deficient macrophages compared with in wild-type cells. 3) M-CSF expression responding to zinc is reduced in MT-deficient fibroblasts compared with in wild-type cells, and increased in MT-overexpressed fibroblasts compared with in control cells. 4) LIF, a STAT3 activating cytokine, protects the heart from ischemia/reperfusion injury. Transgenic mice overexpressing STAT3 have tolerance to ischemia/reperfusion-induced damage, whereas MT-null mutation cancels the myocardial protection. In this review, we discuss the relation of MT and stress responses from the point of view of cytokine-induced expression of MT and modulation of cytokine expression by MT.
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PMID:[Cytokine-induced metallothionein expression and modulation of cytokine expression by metallothionein]. 1740 98

The migration of macrophages through peripheral tissues is an essential step in the host response to infection, inflammation, and ischemia as well as in tumor progression and tissue repair. The mannose receptor (MR; CD206, previously known as the macrophage MR) is a 175-kDa type I transmembrane glycoprotein and is a member of a family of four recycling endocytic receptors, which share a common extracellular domain structure but distinct ligand-binding properties and cell type expression patterns. MR has been shown to bind and internalize carbohydrate and collagen ligands and more recently, to have a role in myoblast motility and muscle growth. Given that the related Endo180 (CD280) receptor has also been shown to have a promigratory role, we hypothesized that MR may be involved in regulating macrophage migration and/or chemotaxis. Contrary to expectation, bone marrow-derived macrophages (BMM) from MR-deficient mice showed an increase in random cell migration and no impairment in chemotactic response to a gradient of CSF-1. To investigate whether the related promigratory Endo180 receptor might compensate for lack of MR, mice with homozygous deletions in MR and Endo180 were generated. These animals showed no obvious phenotypic abnormality, and their BMM, like those from MR-deficient mice, retained an enhanced migratory behavior. As MR is down-regulated during macrophage activation, these findings have implications for the regulation of macrophage migration during different stages of pathogenesis.
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PMID:Mannose receptor regulation of macrophage cell migration. 1759 37


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