Constitutive cyclooxygenase (COX-1; prostaglandin-endoperoxide synthase, EC 1.14.99.1) is present in cells under physiological conditions, whereas COX-2 is induced by some cytokines, mitogens, and endotoxin presumably in pathological conditions, such as inflammation. Therefore, we have assessed the relative inhibitory effects of some nonsteroidal antiinflammatory drugs on the activities of COX-1 (in bovine aortic endothelial cells) and COX-2 (in endotoxinactivated J774.2 macrophages) in intact ceils, broken cells, and purified enzyme preparations (COX-1 in sheep seminal vesicles; COX-2 in sheep placenta). Similar potencies of aspfrin, indomethacin, and ibuprofen against the broken cell and purified enzyme preparations indicated no influence of species. Aspirin, indomethacin, and ibuprofen were more potent inhibitors of COX-1 than COX-2 in all models used. The relative potencies of aspirin and indomethacin varied only slightly between models, although the IC50 values were different.Ibuprofen was more potent as an inhibitor of COX-2 in intact cells than in either broken cells or purified enzymes. Sodium salicylate was a weak inhibitor of both COX isoforms in intact cells and was inactive against COX in either broken cells or purified enzyme preparations. Diclofenac, BW755C, acetaminophen, and naproxen were approximately equipotent inhibitors of COX-1 and COX-2 in intact cells. BF 389, an experimental drug currently being tested in humans, was the most potent and most selective inhibitor of COX-2 in intact cells. Thus, there are clear pharmacological differences between the two enzymes. The use of such models of COX-1 and COX-2 activity will lead to the identification of selective inhibitors of COX-2 with presumably less side effects than present therapies. Some inhibitors had higher activity in intact cells than against purified enzymes, suggesting that pure enzyme preparations may not be predictive of therapeutic action.Cyclo-oxygenase (COX; prostaglandin-endoperoxide synthase, EC 1.14.99.1) converts arachidonic acid to prostaglandin (PG) H2, which is then further metabolized by other enzymes to various PGs, prostacyclin, and thromboxanes (1). COX exists in at least two isoforms with similar molecular weights ("'70 kDa). COX-1 is expressed constitutively and was first characterized, purified, and cloned from sheep vesicular glands (2-7). Activation of COX-1 leads, for instance, to the production of prostacyclin, which when released by the endothelium is antithrombogenic (8) and by the gastric mucosa is cytoprotective (9). COX-2 is induced in cells exposed to proinflammatory agents, including cytokines (10), mitogens (11) and endotoxin (12,13 COX-2 may well explain their therapeutic utility as antiinflammatory drugs, whereas inhibition of COX-1 may explain their unwanted side effects, such as gastric and renal damage.After establishing that bovine aortic endothelial cells in culture contain COX-1 and that endotoxin-activated J774.2 macrophages contain COX-2, we have investigated the inhibitory effects of s...

Multipotent mesenchymal stromal cells (MSCs) represent a rare heterogeneous subset of pluripotent stromal cells that can be isolated from many different adult tissues that exhibit the potential to give rise to cells of diverse lineages. Numerous studies have reported beneficial effects of MSCs in tissue repair and regeneration. After culture expansion and in vivo administration, MSCs home to and engraft to injured tissues and modulate the inflammatory response through synergistic downregulation of proinflammatory cytokines and upregulation of both prosurvival and antiinflammatory factors. In addition, MSCs possess remarkable immunosuppressive properties, suppressing T-cell, NK cell functions, and also modulating dentritic cell activities. Tremendous progress has been made in preclinical studies using MSCs, including the ability to use allogeneic cells, which has driven the application of MSCs toward the clinical setting. This review highlights our current understanding into the biology of MSCs with particular emphasis on the cardiovascular and renal applications, and provides a brief update on the clinical status of MSC-based therapy.

Abstract. Erythropoietin (EPO) is upregulated by hypoxia and causes proliferation and differentiation of erythroid progenitors in the bone marrow through inhibition of apoptosis. EPO receptors are expressed in many tissues, including the kidney. Here it is shown that a single systemic administration of EPO either preischemia or just before reperfusion prevents ischemia-reperfusion injury in the rat kidney. Specifically, EPO (300 U/kg) reduced glomerular dysfunction and tubular injury (biochemical and histologic assessment) and prevented caspase-3, -8, and -9 activation in vivo and reduced apoptotic cell death. In human (HK-2) proximal tubule epithelial cells, EPO attenuated cell death in response to oxidative stress and serum starvation. EPO reduced DNA fragmentation and prevented caspase-3 activation, with upregulation of Bcl-X L and XIAP. The antiapoptotic effects of EPO were dependent on JAK2 signaling and the phosphorylation of Akt by phosphatidylinositol 3-kinase. These findings may have major implications in the treatment of acute renal tubular damage.Erythropoietin (EPO) is the major regulator of proliferation and differentiation of erythroid progenitor cells through its antiapoptotic actions (1). EPO gene expression is under the control of the oxygen-sensitive transcription factor hypoxiainducible factor (HIF-1), which consists of the regulatory subunit HIF-1␣ and the constitutively expressed subunit HIF-1␤. Low oxygen tension adverts enzymatic prolyl-residue hydroxylation by prolyl-4-hydroxylase, which, in normoxia, serves as a signal for polyubiquitination and proteosomal degradation, thereby preventing von-Hippel-Lindau (VHL)-dependent HIF degradation, leading to nuclear accumulation of HIF-1 (2). HIF-1 controls the expression of several cytokines that mediate the adaptive response to ischemia, including vascular endothelial growth factor and glucose metabolism. The prolyl-4-hydroxylase requires iron as a co-factor, and cobalt mimics the effect of hypoxia on HIF-1␣ activation (3). Cobalt administration to rats caused upregulation of HIF-dependent proteins, including EPO, and diminished the degree of renal injury caused by ischemia-reperfusion (I/R), suggesting the HIF/EPO pathway may play an important role in ischemic preconditioning (4). EPO is upregulated in the brain and spinal cord after hypoxic stimuli and protects neurones against ischemic or oxidative injury in vivo and in vitro (5,6). The neuroprotective effects of EPO are dependent on EPO receptormediated JAK2 phosphorylation and NF-B-dependent transcription of antiapoptotic genes, including endogenous inhibitors of apoptosis XIAP and cIAP-2 (7). In the retina, EPO upregulation is essential for hypoxic preconditioning via HIF-1␣ stabilization. The systemic administration of recombinant EPO also reduces the degree of retinal apoptosis induced by high-intensity light insult (8). EPO receptor-mediated intracellular signaling may involve nuclear translocation of the transcription factor NF-B and phosphorylation of Akt (protein kinase B) by phosph...

Summary. Background: Acute traumatic coagulopathy (ATC) is an impairment of hemostasis that occurs early after injury and is associated with a 4-fold higher mortality, increased transfusion requirements and organ failure. Objectives: The purpose of the present study was to develop a clinically relevant definition of ATC and understand the etiology of this endogenous coagulopathy. Patients/methods: We conducted a retrospective cohort study of trauma patients admitted to five international trauma centers and corroborated our findings in a novel rat model of ATC. Coagulation status on emergency department arrival was correlated with trauma and shock severity, mortality and transfusion requirements. 3646 complete records were available for analysis. Results: Patients arriving with a prothrombin time ratio (PTr) > 1.2 had significantly higher mortality and transfusion requirements than patients with a normal PTr (mortality: 22.7% vs. 7.0%; P < 0.001. Packed red blood cells: 3.5 vs. 1.2 units; P < 0.001. Fresh frozen plasma: 2.1 vs. 0.8 units; P < 0.001). The severity of ATC correlated strongly with the combined degree of injury and shock. The rat model controlled for exogenously induced coagulopathy and mirrored the clinical findings. Significant coagulopathy developed only in animals subjected to both trauma and hemorrhagic shock (PTr: 1.30. APTTr: 1.36; both P < 0.001 compared with sham controls). Conclusions: ATC develops endogenously in response to a combination of tissue damage and shock. It is associated with increased mortality and transfusion requirements in a dose-dependent manner. When defined by standard clotting times, a PTr > 1.2 should be adopted as a clinically relevant definition of ATC.