Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0002871 (anemia)
 52,094 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cyclooxygenase (COX) plays a key regulatory role in prostaglandin synthesis. COX-2 is inducible and is the major isoform of inflammatory cells. COX-2-deficient mice were shown to have normal basal hematopoiesis and hematology. We hypothesized that COX-2 induction plays a role in the recovery phase of 5-fluorouracil (5-FU) induced bone marrow injury, because significant macrophage-driven phagocytic removal of necrotic debris and stromal cell reorganization of repopulating marrow occur after 5-FU induction of bone marrow necrosis. Hematologic recovery was markedly delayed with moderately severe leukopenia, thrombocytopenia and reticulocytopenia compared to heterozygotes on day 8 or 12 in Cox-2-/- mice. Mild anemia was present in 5-FU-treated Cox-2-/- and Cox-2+/- mice on days 8 and 12, which was more severe in Cox-2-/- mice. Cox-2-/- mice had markedly decreased bone marrow cell counts per femur and reduced numbers of erythroid and myeloid colony-forming cells compared to heterozygote mice on days 8 and 12 post 5-FU. Histologic examination of 5-FU-treated Cox-2-/- mice revealed a failure to repopulate the intact marrow stroma with hematopoietic cells. Accelerated erythropoiesis following phenylhydrazine-induced hemolytic anemia, however, was comparable between Cox-2-/- and Cox+/- mice, as were induced levels of renal erythropoietin mRNA. COX-2 induction is likely a central event in the accelerated hematopoiesis following myelotoxic injury, because recovery from 5-FU-induced myeloablation is markedly impaired in Cox-2-/- mice but is normal after phenylhydrazine induction of anemia.
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PMID:Cyclooxygenase-2 is essential for normal recovery from 5-fluorouracil-induced myelotoxicity in mice. 1090 34

NSAID-induced intestinal toxicity is more common than previously recognized and may have clinically significant sequelae, especially in elderly arthritic patients. Increased awareness of the potential intestinal complications associated with prostaglandin inhibition is required for early recognition and appropriate management. An increase in the level of suspicion by physicians may lead to earlier diagnosis and subsequent discontinuation of the offending NSAID; this is important in that discontinuation of the offending agent may be preferable to multiple endoscopic radiologic and surgical procedures in the patient with obscure blood loss and anemia. Appropriate diagnosis in selected patients may prevent the increased morbidity and mortality associated with small intestinal surgery. The emergence of selective COX-2 inhibitors likely will bring this issue to the forefront because it will become increasingly important to determine the effects of these agents on the small intestine and colon, in addition to their effects on the gastroduodenal mucosa. The new generation of selective COX-2 inhibitors may offer a potential therapeutic advantage over the nonselective NSAIDs with respect to their intestinal toxicity. Well-designed safety trials that have intestinal injury as a predefined end point will provide important information as to the overall gastrointestinal safety of these compounds. These agents must be evaluated with respect to their overall safety profile and not just by their gastrointestinal safety. Nevertheless, these agents are continuing to provide new directions for exciting basic and clinical scientific investigation.
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PMID:Clinical implications of prostaglandin inhibition in the small bowel. 1176 37

Side effects of the distal gastrointestinal tract after NSAID use are common and more frequent than previously recognized. Increased mucosal permeability and mucosal inflammation are often silent but appear after NSAID treatment with most dual COX inhibitors. Other clinical manifestations include: anemia, occult blood loss, malabsorption, protein-loss, ileal dysfunction, diarrhea, mucosal ulceration and strictures due to diaphragm disease. More common complications are lower gastrointestinal bleeding and perforation, which represent at least one third of all gastrointestinal complications observed with NSAID use. Studies with selective COX-2 inhibitors have shown that, in the short term, these agents do not increase mucosal permeability or induce anemia due to occult bleeding and that, when compared to dual COX inhibitors, lower gastrointestinal complications may be reduced by 50%. In order to minimize the impact of these side effects, it is important to increase the current standards of suspicion by physicians who treat these patients, since drug discontinuation may further reduce damage, and clinical experience with agents that may prevent or treat distal tract damage is very limited. From this perspective, selective COX-2 inhibitors may be the drugs of choice in the high-risk patient that needs NSAIDs. Another important area of uncertainty is the impact of NSAID use in patients with inflammatory bowel diseases. Data from different animal models of inflammatory bowel disease suggest that inhibition of both COX-1 and COX-2 derived prostaglandins affects the severity of the mucosal inflammation. However, current epidemiological and clinical data are contradictory. Since many patients.
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PMID:Clinical implications of COX-1 and/or COX-2 inhibition for the distal gastrointestinal tract. 1452 5

The side effects of NSAIDs are equally evident in the stomach and the small bowel. The latter is increasingly seen as being clinically significant, contributing substantially to the iron-deficiency anaemia that is so common in patients with rheumatoid arthritis. Furthermore, NSAID-enteropathy may be associated with life-threatening events. The pathogenesis of NSAID-enteropathy is uncertain but inhibition of COX-1 is believed to be of pivotal importance. However there is increasing evidence that COX-2 inhibition and the topical effect may have a synergistic detrimental action. We examined the role of COX-1, COX-2 and the so called topical effect of acidic NSAIDs. We found that COX-1 or COX-2 inhibition and the topical effect alone do not damage the GI tract. Dual inhibition of COX-1 and COX-2 results in intestinal inflammation similar to that caused by Indomethacin. The topical effect may act synergistically in this damage. The conventional view that the mechanism of gastrointestinal damage is principally caused by COX-1 inhibition needs to be revised in view of recent studies using selective inhibitors of the COX enzymes and COX knockout animals.
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PMID:COX-1, COX-2 and the topical effect in NSAID-induced enteropathy. 1503 90

In sickle cell disease, intravascular sickling and attendant flow abnormalities underlie the chronic inflammation and vascular endothelial abnormalities. However, the relationship between sickling and vascular tone is not well understood. We hypothesized that sickling-induced vaso-occlusive events and attendant oxidative stress will affect microvascular regulatory mechanisms. In the present studies, we have examined whether microvascular abnormalities expressed in sickle transgenic-knockout Berkeley (BERK) mice (which express exclusively human alpha- and beta(S)-globins with <1% gamma-globin levels) are amenable to correction with increased levels of antisickling fetal hemoglobin (HbF). In BERK mice, sickling, increased oxidative stress, and hemolytic anemia are accompanied by vasodilation, compensatory increases in eNOS and COX-2, and attenuated vascular responses to NO-mediated vasoactive stimuli and norepinephrine. The hypotension and vasodilation (required for adequate oxygen delivery in the face of chronic anemia) are mediated by non-NO vasodilators (i.e., prostacyclin) as evidenced by induction of COX-2. In BERK mice, the resistance to NO-mediated vasodilators is associated with increased oxidative stress and hemolytic rate, and in BERK + gamma mice (expressing 20% HbF), an improved response to these stimuli is associated with reduced oxidative stress and hemolytic rate. Furthermore, BERK + gamma mice show normalization of vessel diameters, and eNOS and COX-2 expression. These results demonstrate a strong relationship between sickling and microvascular function in sickle cell disease.
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PMID:Effect of fetal hemoglobin on microvascular regulation in sickle transgenic-knockout mice. 1548 61

Ulcerative colitis (UC) patients frequently require iron supplementation to remedy anemia. The impact of systemic iron supplementation (intraperitoneal injection) on UC-associated carcinogenesis was assessed in mice subjected to cyclic dextran sulfate sodium (DSS) treatment and compared with dietary iron enrichment. Systemic iron supplementation, but not a twofold iron diet, remedied iron deficiency as indicated by the histochemical detection of splenic iron stores. A twofold iron diet, but not systemic iron, increased iron accumulation in colonic luminal contents, at the colonic mucosal surface, and in superficial epithelial cells. Colitis-associated colorectal tumor incidence after 15 DSS cycles was not affected by systemic iron (2/28; 7.1%) compared to nonsupplemented controls (4/28; 14.1%) but was significantly increased by the twofold iron diet (24/33; 72.7%) (P < 0.001). Mechanistic study revealed that systemic iron had no effect on DSS-induced inflammation, or colonic iNOS and COX-2 protein levels, compared to controls. Systemic iron supplementation for 16 weeks replenished splenic iron in a spontaneous colitis model (interleukin-2-deficient mice) and significantly reduced colonic inflammation compared to interleukin-2 (-/-) controls without increasing hyperplastic lesions. These results suggest that iron supplemented systemically could be used to remedy anemia in UC patients without exacerbating inflammation or enhancing colon cancer risk. These findings need to be verified in clinical studies.
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PMID:Systemic iron supplementation replenishes iron stores without enhancing colon carcinogenesis in murine models of ulcerative colitis: comparison with iron-enriched diet. 1584 5

The gastrointestinal toxicity of conventional nonsteroidal antiinflammatory drugs (NSAIDs) is not confined to the stomach and proximal duodenum but extends also to the rest of the small bowel, colon, and rectum. Long-term NSAID therapy usually induces clinically silent enteropathy characterized by increased intestinal permeability and inflammation. Chronic occult bleeding and protein loss may result in iron-deficiency anemia and hypoalbuminemia. NSAIDs can also induce small bowel ulcers that infrequently lead to acute bleeding, perforation, or chronic scarring responsible for diaphragm-like strictures. At the colon and rectum, NSAID use can result in de novo lesions such as nonspecific colitis and rectitis, ulcers, and diaphragm-like strictures. NSAIDs have been implicated in the development of segmental ischemic colitis. In patients with diverticular disease, NSAID use increases the risk of severe diverticular infection and perforation. NSAIDs can trigger exacerbations of ulcerative colitis or Crohn's disease. With selective COX-2 inhibitors, the risk of gastrointestinal toxicity is reduced as compared to conventional NSAIDs but is not completely eliminated. Experimental studies suggest that long-term COX-2 inhibitor therapy may cause damage to the previously healthy small bowel. Similar to conventional NSAIDs, COX-2 inhibitors may be capable of triggering exacerbations of inflammatory bowel disease.
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PMID:Toxic effects of nonsteroidal antiinflammatory drugs on the small bowel, colon, and rectum. 1603 40

Upper gastrointestinal (GI) complications are well-recognized adverse events associated with non-steroidal anti-inflammatory drug (NSAID) use. However, NSAID-induced damage to the distal GI tract is also common and more frequent than previously recognized. These untoward effects include increased mucosal permeability, mucosal inflammation, anemia and occult blood loss, malabsorption, protein loss, ileal dysfunction, diarrhea, mucosal ulceration, strictures due to diaphragm disease as well as active bleeding and perforation. Studies with selective COX-2 inhibitors have shown that, in the short term, these agents do not increase mucosal permeability and display a reduced by 50% incidence of serious lower GI side effects compared to traditional NSAIDs. However, the long-term use of this therapeutic strategy is limited by the increased risk of serious cardiovascular events, especially in patients with multiple risk factors. Several studies have suggested that intraluminal bacteria play a significant role in the pathogenesis of small-bowel damage induced by NSAIDs and that enterobacterial translocation into the mucosa represents the first step that sets in motion a series of events leading to gross lesion formation. Experimental and clinical investigations indicate that in the short term, antibacterial agents either reduce or abolish NSAID enteropathy. However, potential adverse effects of systemic antimicrobials and the possible occurrence of drug resistance have so far precluded this interesting approach. The availability of poorly absorbed and effective antibiotics, like rifaximin, may represent an attractive alternative to prevent or limit NSAID-associated intestinal damage.
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PMID:Microbial flora in NSAID-induced intestinal damage: a role for antibiotics? 1649 62

Several observations imply that atypical rheumatic manifestations may be associated with occult neoplasia. A 71-year-old woman was admitted to the hospital three times in 2 years. Initially, she was admitted for investigation of an iron-deficient anemia associated with upper intestinal tract symptoms. Endoscopy revealed hiatus hernia, esophagitis, and duodenal ulcer with a Helicobacter pylori infection, but there were no signs of malignancy, and the patient received appropriate drug treatment. Two years later, she presented with arthralgias concerning the upper and lower limbs in an asymmetrical distribution, low fever, and persistence of the anemia, despite the treatment she had received and the fact that her gastrointestinal symptoms had long ceased. Immunological assays showed no specific rheumatic disorder, and the patient was discharged after showing significant improvement with the use of COX-2 selective NSAIDs. Finally, 4 months later, she was readmitted with worsening of the arthralgias, arthritis in the right radiocarpal joint, and severe anemia. Hematemesis that occurred during her hospital stay led to an emergency endoscopy and the diagnosis of gastric adenocarcinoma. Only a few cases have been reported so far concerning rheumatic manifestations as signs of an occult gastric cancer. Thus, there must be some degree of suspicion when dealing with patients with anemia and rheumatic symptoms that cannot be classified into a particular rheumatologic entity, because they might conceal a gastrointestinal malignancy not yet evident.
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PMID:Rheumatic-like syndrome as a symptom of underlying gastric cancer. 1657 85

Cytokines and effector molecules are important immunoregulatory molecules in human malaria. Tumor necrosis factor (TNF)-alpha limits malaria parasitemia but also promotes pathogenesis at high concentrations, whereas prostaglandin E2 (PGE2) inhibits TNF-alpha production and is reduced in childhood malaria, at least in part, through suppression of cyclooxygenase (COX)-2 following the ingestion of Plasmodium falciparum hemozoin (pfHz; malarial pigment) by peripheral blood mononuclear cells (PBMCs). Although molecular interactions between TNF-alpha and PGE2 are largely unexplored in human malaria, results presented here show that pfHz-induced suppression of PBMC COX-2 gene products induces overproduction of TNF-alpha. Moreover, addition of exogenous PGE2 to pfHz-treated PBMCs dose-dependently decreased TNF-alpha production, whereas experimental COX inhibitors and antipyretics used during human malaria generated increased TNF-alpha production. Healthy, malaria-exposed children had elevated levels of circulating bicyclo-PGE2/TNF-alpha, compared with children with malarial anemia (P<.01), with systemic bicyclo-PGE2 and TNF-alpha significantly associated with hemoglobin concentrations (r=0.745; P<.01). The results of the present study illustrate that pfHz-induced suppression of PGE2 promotes overproduction of TNF-alpha, which is associated with enhanced malarial anemia.
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PMID:Suppression of prostaglandin E2 by malaria parasite products and antipyretics promotes overproduction of tumor necrosis factor-alpha: association with the pathogenesis of childhood malarial anemia. 1661 86


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