Search results for "Heme O"
showing 10 items of 98 documents
Analysis of early biochemical markers and regulation by tin protoporphyrin IX in a model of spontaneous osteoarthritis
2011
Abstract Age-related changes in joint tissues lead to osteoarthritis (OA). Detection of early changes in OA patients may help to initiate treatments before the establishment of irreversible joint destruction. STR/ort mice develop with age a severe degenerative joint disease that resembles human OA thus allowing the investigation of biochemical markers as well as new treatments in an accelerated time frame. We have analyzed the changes in serum levels of different mediators during the early phases of idiopathic OA in STR/ort mice. Serum levels of matrix metalloproteinase-3 (MMP-3) but not those of tumor necrosis factor-α, interleukin(IL)-1β, IL-17 or prostaglandin E 2 correlated with histopa…
Haem oxygenase-1 down-regulates high mobility group box 1 and matrix metalloproteinases in osteoarthritic synoviocytes
2010
Objectives. Activation of osteoarthritic synoviocytes by pro-inflammatory cytokines results in the release of biochemical mediators such as MMPs and high mobility group box 1 (HMGB1). Extracellular HMGB1 can play an important role in joint diseases as a mediator of synovitis. We have shown previously that haem oxygenase-1 (HO-1) exerts protective effects during inflammatory responses. In this study, we have examined whether HO-1 induction would be an effective strategy to control MMP and HMGB1 production in osteoarthritic synoviocytes. Methods. Osteoarthritic synoviocytes were obtained by digestion with collagenase and cultured until third passage. HO-1 was induced by cobalt protoporphyrin …
Carbon Monoxide Protects Against Ischemia-reperfusion Injury in Vitro via Antioxidant Properties
2012
Carbon monoxide (CO) is believed to mediate many of the cytoprotective effects attributed to the activation of heme oxygenase (HO-1), the enzyme responsible for CO production. Recently, the study of CO-releasing molecules (CO-RMs) has provided a new approach for the delivery of CO. In the present study, we examined whether the cardioprotective properties of CO-RM2 in isolated rat hearts subjected to an ischemia-reperfusion (I/R) sequence were associated with the presence of CO. In addition, the antioxidant properties of CO-RM2 were evaluated. In hearts pretreated with CO-RM2, the improvement in contractile function at the end of the reperfusion period after 20 min of global total ischemia w…
Induction of hepatic heme oxygenase-1 by diclofenac in rodents: role of oxidative stress and cytochrome P-450 activity
2003
Abstract Background/Aims : The role of oxidative stress in diclofenac hepatotoxicity is still not clear. This study examined whether the drug induced heme oxygenase-1 (HO-1), a stress protein. Methods : HO-1 mRNA and HO activity were measured in mouse liver and in rat hepatocytes after treatment with diclofenac parallel to release of serum alanine aminotransferase (ALT) and sorbitol dehydrogenase (SDH) as a marker of hepatic damage. Results : HO-1 was transcriptionally and dose-dependently induced by diclofenac in mouse liver and rat hepatocytes. HO-1 mRNA, ALT and SDH peaked at the same time. Mechanistic studies revealed that the drug synergized with buthionine sulfoximine (BSO) in lowerin…
Control of Cell Migration and Inflammatory Mediators Production by CORM-2 in Osteoarthritic Synoviocytes
2011
Background Osteoarthritis (OA) is the most widespread degenerative joint disease. Inflamed synovial cells contribute to the release of inflammatory and catabolic mediators during OA leading to destruction of articular tissues. We have shown previously that CO-releasing molecules exert anti-inflammatory effects in animal models and OA chondrocytes. We have studied the ability of CORM-2 to modify the migration of human OA synoviocytes and the production of chemokines and other mediators sustaining inflammatory and catabolic processes in the OA joint. Methodology/Principal Findings OA synoviocytes were stimulated with interleukin(IL)-1β in the absence or presence of CORM-2. Migration assay was…
Heme oxygenase-1: a novel key player in the development of tolerance in response to organic nitrates.
2007
Objective— Nitrate tolerance is likely attributable to an increased production of reactive oxygen species (ROS) leading to an inhibition of the mitochondrial aldehyde dehydrogenase (ALDH-2), representing the nitroglycerin (GTN) and pentaerythrityl tetranitrate (PETN) bioactivating enzyme, and to impaired nitric oxide bioactivity and signaling. We tested whether differences in their capacity to induce heme oxygenase-1 (HO-1) might explain why PETN and not GTN therapy is devoid of nitrate and cross-tolerance. Methods and Results— Wistar rats were treated with PETN or GTN (10.5 or 6.6 μg/kg/min for 4 days). In contrast to GTN, PETN did not induce nitrate tolerance or cross-tolerance as assess…
Hemin, an inducer of heme oxygenase-1, lowers intraocular pressure in rabbits.
2007
Carbon monoxide (CO) generated from heme may induce vasodilation and exert cyto-protective properties in the eye. This study was undertaken to investigate the effects of hemin, a potent inducer of heme oxygenase-1 (HO-1), on models of ocular hypertension in rabbits.Ocular hypertension was induced by injecting alpha-chymotrypsin in both eyes under local anesthesia. Only rabbits with an intraocular pressure (IOP) of 25 mmHg or more were used. The dose-response study of the hemin effect on IOP was made by an intravenous injection of the drug (50, 75, and 100 mg/kg) and subsequent IOP monitoring every 6 h. A separate set of animals was pretreated with the HO-1 inhibitor, zinc protoporphyrin-IX …
Expression of heme oxygenase-1 and regulation by cytokines in human osteoarthritic chondrocytes
2003
Heme oxygenase-1 (HO-1) is implicated in the protection against tissue injury. We investigated the expression of this protein in cartilage sections and chondrocytes obtained from osteoarthritic patients. HO-1 was immunodetected in preparations from cartilage and also in chondrocytes cultured in the absence of stimulation. We found that HO-1 can be modulated by cytokines since the pro-inflammatory cytokines interleukin (IL)-1beta, IL-17 and tumour necrosis factor-alpha (TNF-alpha) down-regulated this protein, whereas the anti-inflammatory cytokine IL-10 exerted the opposite effect. Our results suggest a role for HO-1 as part of protective mechanisms against tissue injury in human cartilage.
Beneficial effect of dipyridyl, a liposoluble iron chelator against focal cerebral ischemia: In vivo and in vitro evidence of protection of cerebral …
2007
Whereas iron chelators were shown to induce neuroprotection against brain injury, the effect of iron chelators on ischemia-induced damage of cerebral endothelium is largely unknown. Our objective was to explore the endothelioprotective effect of the lipophilic iron chelator dipyridyl (DP) (i) in vitro on the death of cerebral endothelial cells (CECs) subjected to intracellular iron loading and (ii) in vivo on the ischemia-induced blood-brain barrier (BBB) disruption. When given shortly after iron exposure or brain ischemia, DP prevented the death of CECs and diminished BBB disruption, respectively, whereas a delayed administration of DP was associated with a lower CECs protection. Interesti…
Heme oxygenase-1 regulates the progression of K/BxN serum transfer arthritis.
2012
Background Heme oxygenase-1 (HO-1) is induced in many cell types as a defense mechanism against stress. We have investigated the possible role of endogenous HO-1 in the effector phase of arthritis using the K/BxN serum transfer model of arthritis in HO-1 heterozygous and homozygous knock-out mice. Methodology/Principal Findings Arthritis was induced in C57/Black-6 xFVB (HO-1+/+, HO-1+/− and HO-1−/−) mice by intraperitoneal injection of 150 µl serum from arthritic K/BxN mice at days 0 and 2. Blood was collected and animals were sacrificed at day 10. Histological analysis was performed in ankle sections. The levels of inflammatory mediators were measured in serum and paw homogenates by enzyme…