Gastrointestinal safety of coxibs: systematic review and meta‐analysis of observational studies on selective inhibitors of cyclo‐oxygenase 2

Prior meta‐analyses have shown a higher gastrointestinal risk of nonselective NSAIDs versus placebo and a lower gastrointestinal risk of coxibs versus nonselective NSAIDs. However, the available data about gastrointestinal risk for coxibs versus placebo are scarce. The aim of this study was to review the current evidence on the use of coxibs and to evaluate the risk of gastrointestinal adverse outcomes (GAO) associated with coxibs versus nonexposed. Search was conducted on PubMed and Embase databases. We selected cohort observational, case‐control, nested case‐control and case‐crossover studies that reported the risk of GAO associated with coxibs versus nonexposed as relative risk (RR), odds ratio (OR), hazard ratio (HR) or incidence rate ratio (IRR). It was estimated the pooled RR and the 95% confidence interval (CI) for coxibs both individually and as a whole by the DerSimonian and Laird method. Twenty‐eight studies met inclusion criteria. Overall, coxibs were associated with a significant increment in the risk of GAO [RR 1.64 (95% CI 1.44–1.86)]. The analysis by individual drugs showed that etoricoxib [RR 4.85 (95% CI 2.64–8.93)] presented the highest gastrointestinal risk, followed by rofecoxib [RR 2.02 (95% CI 1.56–2.61)] and celecoxib [RR 1.53 (95% CI 1.19–1.97)]. Gastrointestinal risk was also high for the subgroups aged <65 years and low‐dose coxibs. The use of coxibs is associated with a statistically significant increased risk of GAO, which would be high even for low‐dose coxibs and <65‐year‐old subgroups. The risk would be higher for etoricoxib than for celecoxib and rofecoxib.     

Cardioprotective effect of hemin in isoprenaline-induced myocardial infarction: role of ATP-sensitive potassium channel and endothelial nitric oxide synthase

Ischemic heart disease is a common cardiac health problem. Despite the significant advances in prevention and treatment of this disorder, its incidences and complications are very serious. So, the search for more antioxidants and anti-inflammatory agents with cardioprotective effects is an urgent task. We aimed to evaluate the effects of a heme oxygenase 1 (HO1) inducer, hemin (HEM), on isoprenaline (ISO)-induced myocardial damage. Forty-five Wistar albino rats were used. Animals were treated with HEM (25 mg/kg/day) i.p. for 5 days and injected with ISO (150 mg/kg/day) i.p. on 4th and 5th day of the experiment. Detection of the role of ATP-sensitive potassium channel (K_ATP) was performed by administration of glibenclamide (GP) (5 mg/kg/day) orally 2 h before HEM. Moreover, the role of endothelial nitric oxide synthase (eNOS) was detected by coadministration of Nitro- ω-L-arginine (L-NNA) (25 mg/kg/day) for 5 days. The ISO group showed increase in heart weight, cardiac enzymes, tumor necrosis factor alpha (TNFα), and malondialdehyde (MDA) with decrease in reduced glutathione (GSH), HO1, and total antioxidant capacity (TAC). In addition, there were increases in Bcl-2 associated X protein (Bax) and cleaved caspase-3, but decreases in B-cell lymphoma-2 (Bcl-2) and eNOS. Moreover, the histopathological examination of the ISO group showed degeneration of the cardiac muscle fibers and marked infiltration of the inflammatory cells. The biochemical and histopathological changes induced by ISO were markedly ameliorated in the HEM plus ISO group. This protective effect was diminished with coadministration of GP or L-NNA; thus, K_ATP and eNOS might mediate HEM cardioprotection.     

Carbon monoxide controls microglial erythrophagocytosis by regulating CD36 surface expression to reduce the severity of hemorrhagic injury

Microglial erythrophagocytosis is crucial in injury response to hemorrhagic stroke. We hypothesized that regulation of microglial erythrophagocytosis via HO-1/CO depends on a pathway involving reactive oxygen species (ROS) and CD36 surface-expression. The microglial BV-2 cell line and primary microglia (PMG) were incubated +/−blood and +/−CO-exposure. PMG isolated from tissue-specific HO-1-deficient (LyzM-Cre-Hmox1 ^fl/fl) and CD36 ^−/− mice or siRNA against AMPK (AMP-activated protein kinase) were used to test our hypothesis. In a murine subarachnoid hemorrhage (SAH) model, we compared neuronal injury in wild-type and CD36 ^−/− mice. Readouts included vasospasm, microglia activation, neuronal apoptosis, and spatial memory. We observed increased microglial HO-1-expression after blood-exposure. A burst in ROS-production was seen after CO-exposure, which led to increased amounts of phosphorylated AMPK with subsequently enhanced CD36 surface-expression. Naïve PMG from LyzM-Cre-Hmox1 ^fl/fl mice showed reduced ROS-production and CD36 surface-expression and failed to respond to CO with increased CD36 surface-expression. Lack of HO-1 and CD36 resulted in reduced erythrophagocytosis that could not be rescued with CO. Erythrophagocytosis was enhanced in BV-2 cells in the presence of exogenous CO, which was abolished in cells treated with siRNA to AMPK. CD36 ^−/− mice subjected to SAH showed enhanced neuronal cell death, which resulted in impaired spatial memory function. We demonstrate that microglial phagocytic function partly depends on a pathway involving HO-1 with changes in ROS-production, phosphorylated AMPK, and surface expression of CD36. CD36 was identified as a crucial component in blood clearance after hemorrhage that ultimately determines neuronal outcome. These results demand further investigations studying the potential neuroprotective properties of CO.     

Effect of the heme oxygenase gene on mycelial growth and polysaccharide synthesis in Ganoderma lucidum

The heme oxygenase gene has antioxidant and cytoprotective effects in organisms, but no related research has been conducted in Ganoderma lucidum. For the first time, we cloned the HMX1 gene in G. lucidum. The CDS is 1092 bp in length and encodes 363 amino acids. The HMX1 protein was prokaryotically expressed and purified, and the enzyme activity of the purified protein was measured. The value of K_m was 0.699 μM, and V_m was 81.9 nmol BV h⁻¹ nmol⁻¹ protein. By constructing the silencing vector pAN7-dual-HMX1i, the transformants HMX1i1 and HMX1i2 were obtained. Compared with the wild-type (WT), the average growth rate of HMX1i1 and HMX1i2 decreased by 31% and 23%, respectively, and the mycelium biomass decreased by 53% and 48%, respectively. Compared with the WT, the extracellular polysaccharide content of HMX1i1 and HMX1i2 increased by 59% and 51%, and the intracellular polysaccharide content increased by 24% and 22%, respectively. These results indicate that the HMX1 gene affects mycelial growth and polysaccharide synthesis in G. lucidum.     

Heme Oxygenase-1 Regulates Myeloid Cell Trafficking in AKI

Renal ischemia-reperfusion injury is mediated by a complex cascade of events, including the immune response, that occur secondary to injury to renal epithelial cells. We tested the hypothesis that heme oxygenase-1 (HO-1) expression, which is protective in ischemia-reperfusion injury, regulates trafficking of myeloid-derived immune cells in the kidney. Age-matched male wild-type (HO-1^+/+), HO-1–knockout (HO-1^−/−), and humanized HO-1–overexpressing (HBAC) mice underwent bilateral renal ischemia for 10 minutes. Ischemia-reperfusion injury resulted in significantly worse renal structure and function and increased mortality in HO-1^−/− mice. In addition, there were more macrophages (CD45⁺ CD11b^hiF4/80^lo) and neutrophils (CD45⁺ CD11b^hi MHCII⁻ Gr-1^hi) in HO-1^−/− kidneys than in sham and HO-1^+/+ control kidneys subjected to ischemia-reperfusion. However, ischemic injury resulted in a significant decrease in the intrarenal resident dendritic cell (DC; CD45⁺MHCII⁺CD11b^loF4/80^hi) population in HO-1^−/− kidneys compared with controls. Syngeneic transplant experiments utilizing green fluorescent protein–positive HO-1^+/+ or HO-1^−/− donor kidneys and green fluorescent protein–negative HO-1^+/+ recipients confirmed increased migration of the resident DC population from HO-1^−/− donor kidneys, compared to HO-1^+/+ donor kidneys, to the peripheral lymphoid organs. This effect on renal DC migration was corroborated in myeloid-specific HO-1^−/− mice subjected to bilateral ischemia. These mice also displayed impaired renal recovery and increased fibrosis at day 7 after injury. These results highlight an important role for HO-1 in orchestrating the trafficking of myeloid cells in AKI, which may represent a key pathway for therapeutic intervention.     

New perspectives on male fertility evaluation: Innovative approach for the qualitative analysis of spermatozoa

The identification of idiopathic infertility cases, actually, is impossible. Among new functional tests, developed to improve the male fertility diagnosis, the evaluation of spermatic myo-inositol (MI) level, known as Andrositol^® test (AT), is one of the most interesting, considering its weak economic burden and ease of use. The aim of this study was to evaluate the predictive power of AT and its potential use for a preliminary evaluation of semen samples. To evaluate the predictive power of AT, 87 sperm samples were analysed in comparison with spermiogram and sperm chromatin dispersion (SCD) Test, the gold standard analyses for male fertility evaluation. The application of AT resulted very useful for a preliminary sample evaluation, predicting the absence of DNA fragmentation in case of Low Responder samples precisely, and the presence of DNA fragmentation in case of medium or High Responder samples with abnormal morphology, predicting SCD results with a probability of 80% for Medium Responder sample and of 96.7% for High Responder sample. Considering the predictive power of this method, we could imagine, as preliminary qualitative analysis, its application before SCD test, deepening sperm analysis, improving the daily activities of laboratory operators and maintaining a good reliability of sperm evaluation.     

Implications of uterine NK cells and regulatory T cells in the endometrium of infertile women

A range of studies have shown that the complex process of implantation and an establishment of a pregnancy also involves immune factors. Disturbances in these underlying immune mechanisms might lead to implantation and pregnancy failure and may be involved in the pathogenesis of unexplained infertility. Several studies have reported that imbalances in uterine NK (uNK) cell abundance are associated with infertility; however, controversies exist. An increased amount of CD56⁺ uNK cells along with a decrease in CD16⁺ uNK cells have been associated with normal fertility in some studies. Very few studies of FoxP3⁺ regulatory T cells (Tregs) in the pre-implantation endometrium have been performed. Results are sparse and controversial, studies reporting both increased and decreased numbers of Tregs, respectively, in women suffering from infertility. In conclusion, studies imply that uNK cells, Tregs and HLA-G carry pivotal roles regarding the establishment of a healthy pregnancy, and that abnormal immune mechanisms involving these parameters may be associated with infertility. However, more research in early phases of the reproductive cycle, such as investigating the conditions in the endometrium before implantation, is needed to further clarify the underlying mechanisms.     

Haem oxygenase-1 genotype and cardiovascular adverse events in patients with peripheral artery disease

BACKGROUND: A functional GT dinucleotide length polymorphism in the haem oxygenase-1 (HO-1) gene promoter is thought to be involved in the pathogenesis of cardiovascular disease. Short (< 25) (GT)n repeats are suggested to facilitate enhanced HO-1 up-regulation in response to injury and confer potent anti-inflammatory and antioxidative effects. MATERIALS AND METHODS: We investigated the association between the HO-1 GT-polymorphism and cardiovascular outcome in 472 patients with advanced peripheral artery disease. Cardiovascular risk profile and DNA samples for determination of the HO-1 genotype (carrier vs. noncarrier of a short (GT)n repeat allele) were obtained at baseline, and patients were followed for median 21 months for the occurrence of coronary events (myocardial infarction, percutaneous coronary interventions and coronary artery bypass graft), cerebrovascular events (stroke or carotid revascularization) and all-cause mortality. RESULTS: Coronary events occurred in 48 patients (9%), cerebrovascular events in 40 patients (9%) and 59 patients (13%) died. In total, 173 major adverse cardiovascular events (MACE) occurred in 133 patients (28%). Carriers of the short (GT)n repeat allele had a 0.46-fold reduced adjusted hazard ratio for coronary events (P = 0.016) as compared to noncarriers. No significant difference was found for cerebrovascular events, mortality and overall MACE. CONCLUSION: Apparently, the HO-1 genotype exerts potentially protective effects against coronary adverse events in patients with peripheral artery disease. Homozygous and heterozygous carriers of < 25 (GT)n repeats had lower rates of myocardial infarction, percutaneous coronary interventions and coronary bypass operations compared to patients with longer (GT)n repeats.     

Diverse mechanisms underlying the regulation of ion channels by carbon monoxide

Carbon monoxide (CO) is firmly established as an important, physiological signalling molecule as well as a potent toxin. Through its ability to bind metal-containing proteins, it is known to interfere with a number of intracellular signalling pathways, and such actions can account for its physiological and pathological effects. In particular, CO can modulate the intracellular production of reactive oxygen species, NO and cGMP levels, as well as regulate MAPK signalling. In this review, we consider ion channels as more recently discovered effectors of CO signalling. CO is now known to regulate a growing number of different ion channel types, and detailed studies of the underlying mechanisms of action are revealing unexpected findings. For example, there are clear areas of contention surrounding its ability to increase the activity of high conductance, Ca²⁺-sensitive K⁺ channels. More recent studies have revealed the ability of CO to inhibit T-type Ca²⁺ channels and have unveiled a novel signalling pathway underlying tonic regulation of this channel. It is clear that the investigation of ion channels as effectors of CO signalling is in its infancy, and much more work is required to fully understand both the physiological and the toxic actions of this gas. Only then can its emerging use as a therapeutic tool be fully and safely exploited.

Linked Articles

This article is part of a themed section on Pharmacology of the Gasotransmitters. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-6