Dexamethasone makes the gastric mucosa susceptible to ulceration by inhibiting prostaglandin synthetase and peroxidase--two important gastroprotective enzymes

Drug-Associated Gastropathy: Diagnostic Criteria

Drugs are widely used to treat different diseases in modern medicine, but they are often associated with adverse events. Those located in the gastrointestinal tract are common and often mild, but they can be serious or life-threatening and determine the continuation of treatment. The stomach is often affected not only by drugs taken orally but also by those administered parenterally. Here, we review the mechanisms of damage, risk factors and specific endoscopic, histopathological and clinical features of those drugs more often involved in gastric damage, namely NSAIDs, aspirin, anticoagulants, glucocorticosteroids, anticancer drugs, oral iron preparations and proton pump inhibitors. NSAID- and aspirin-associated forms of gastric damage are widely studied and have specific features, although they are often hidden by the coexistence of Helicobacter pylori infection. However, the damaging effect of anticoagulants and corticosteroids or oral iron therapy on the gastric mucosa is controversial. At the same time, the increased use of new antineoplastic drugs, such as checkpoint inhibitors, has opened up a new area of gastrointestinal damage that will be seen more frequently in the near future. We conclude that there is a need to expand and understand drug-induced gastrointestinal damage to prevent and recognize drug-associated gastropathy in a timely manner.

Glucocorticoid regulation of cancer development and progression

Glucocorticoids are steroid hormones that regulate a host of cellular and physiological functions. However, they are arguably best known for their potent anti-inflammatory properties. Chronic inflammation is well-known to promote the development and progression of numerous types of cancer, and emerging evidence suggests that glucocorticoid regulation of inflammation affects cancer development. However, the timing, intensity, and duration of glucocorticoid signaling have important but often contradictory effects on cancer development. Moreover, glucocorticoids are widely used in parallel with radiation and chemotherapy to control pain, dyspnea, and swelling, but their use may compromise anti-tumor immunity. This review will explore the effects of glucocorticoids on cancer development and progression with particular focus on pro and anti-tumor immunity.

Bioavailability of acalabrutinib suspension delivered via nasogastric tube in the presence or absence of a proton pump inhibitor in healthy subjects

AIMS

Acalabrutinib, a selective Bruton tyrosine kinase inhibitor is approved for the treatment of mantle cell lymphoma and chronic lymphocytic leukemia. Many critically ill patients are unable to swallow and need oral medications to be delivered via a nasogastric (NG) tube. Furthermore, critically ill patients are typically administered proton-pump inhibitors (PPIs) to prevent stress ulcers. Concomitant administration with PPIs reduces acalabrutinib exposure and is not currently recommended. To evaluate acalabrutinib in subjects co-administered with PPIs who require NG delivery, a Phase 1, open-label, randomized, crossover, single-dose study was conducted in healthy subjects.

METHODS

The study assessed the relative bioavailability of an acalabrutinib suspension-in regular, degassed Coca-Cola®-administered via NG tube (Acala-NG) versus the pharmacokinetics (PK) of an acalabrutinib capsule administered orally with water. In addition, the PPI effect was evaluated by comparing the PK following Acala-NG in the presence or absence of rabeprazole.

RESULTS

Exposure of acalabrutinib and its active metabolite (ACP-5862) were comparable following administration of Acala-NG versus the oral capsule (Geo mean ratio, % ref [90% CI]: acalabrutinib AUC_inf : 103 [93-113]; C_max : 144 [120-173]). In addition, exposure was similar following administration of Acala-NG with and without a PPI (Geo mean ratio, % ref [90% CI]: acalabrutinib AUC_inf : 105 [79-138]; C_max : 95 [66-137]). No safety or tolerability concerns were observed, and all adverse events were mild and resolved without treatment.

CONCLUSIONS

Acala-NG with or without a PPI, is safe and well-tolerated without impeding bioavailability.

Dexamethasone sensitizes to ferroptosis by glucocorticoid receptor-induced dipeptidase-1 expression and glutathione depletion

Dexamethasone is widely used as an immunosuppressive therapy and recently as COVID-19 treatment. Here, we demonstrate that dexamethasone sensitizes to ferroptosis, a form of iron-catalyzed necrosis, previously suggested to contribute to diseases such as acute kidney injury, myocardial infarction, and stroke, all of which are triggered by glutathione (GSH) depletion. GSH levels were significantly decreased by dexamethasone. Mechanistically, we identified that dexamethasone up-regulated the GSH metabolism regulating protein dipeptidase-1 (DPEP1) in a glucocorticoid receptor (GR)-dependent manner. DPEP1 knockdown reversed the phenotype of dexamethasone-induced ferroptosis sensitization. Ferroptosis inhibitors, the DPEP1 inhibitor cilastatin, or genetic DPEP1 inactivation reversed the dexamethasone-induced increase in tubular necrosis in freshly isolated renal tubules. Our data indicate that dexamethasone sensitizes to ferroptosis by a GR-mediated increase in DPEP1 expression and GSH depletion. Together, we identified a previously unknown mechanism of glucocorticoid-mediated sensitization to ferroptosis bearing clinical and therapeutic implications.

High altitude exposures and intestinal barrier dysfunction

Gastrointestinal complaints are often reported during ascents to high altitude (> 2500 m), though their etiology is not known. One potential explanation is injury to the intestinal barrier which has been implicated in the pathophysiology of several diseases. High altitude exposures can reduce splanchnic perfusion and blood oxygen levels causing hypoxic and oxidative stress. These stressors might injure the intestinal barrier leading to consequences such as bacterial translocation and local/systemic inflammatory responses. The purpose of this mini review is to 1) discuss the impact of high-altitude exposures on intestinal barrier dysfunction, and 2) present medications and dietary supplements which may have relevant impacts on the intestinal barrier during high-altitude exposures. There is a small but growing body of evidence which shows that acute exposures to high altitudes can damage the intestinal barrier. Initial data also suggests that prolonged hypoxic exposures can compromise the intestinal barrier through alterations in immunological function, microbiota, or mucosal layers. Exertion may worsen high-altitude related intestinal injury via additional reductions in splanchnic circulation and greater hypoxemia. Collectively these responses can result in increased intestinal permeability and bacterial translocation causing local and systemic inflammation. More research is needed to determine the impact of various medications and dietary supplements on the intestinal barrier during high-altitude exposures.

Gastrointestinal Disease and COVID-19: A Review of Current Evidence

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has had an unprecedented and catastrophic impact on humanity and continues to progress. In addition to typical respiratory symptoms such as fever, cough, and dyspnea, a large percentage of COVID-19 patients experience gastrointestinal (GI) complaints, with the most common symptoms being diarrhea, nausea, vomiting, and abdominal discomfort.

SUMMARY

We comprehensively summarize the latest knowledge of the adverse effects of COVID-19 and therapeutic drugs on the GI system, as well as related disease pathogenesis, and then provide a discussion focusing on the management and vaccination of patients who have inflammatory bowel disease (IBD) and GI cancer. The virus can affect the digestive system via binding to ACE2 receptors and subsequent gut microbiome dysbiosis. Through a variety of molecular pathways and mechanisms, numerous drugs for the treatment of COVID-19 could interfere with GI function and lead to multiple clinical manifestations, which may further intensify the risk and severity of GI symptoms of COVID-19 infection, such as nausea, vomiting, gastroparesis, and gastric ulcers.

KEY MESSAGES

We should monitor GI manifestations closely while managing COVID-19 patients and take timely measures to reduce the incidence of SARS-CoV-2 infections in GI cancer patients. IBD patients should receive vaccination timely, but corticosteroid use should be minimized when they are vaccinated. Simultaneously, for persons with IBD who have known or suspected COVID-19, immunosuppressive agents, especially thiopurines, should be avoided/minimized if possible.

Potential Adverse Effects of Dexamethasone Therapy on COVID-19 Patients: Review and Recommendations

In the context of the coronavirus disease 2019 (COVID-19) pandemic, the global healthcare community has raced to find effective therapeutic agents against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To date, dexamethasone is the first and an important therapeutic to significantly reduce the risk of death in COVID-19 patients with severe disease. Due to powerful anti-inflammatory and immunosuppressive effects, dexamethasone could attenuate SARS-CoV-2-induced uncontrolled cytokine storm, severe acute respiratory distress syndrome and lung injury. Nevertheless, dexamethasone treatment is a double-edged sword, as numerous studies have revealed that it has significant adverse impacts later in life. In this article, we reviewed the literature regarding the adverse effects of dexamethasone administration on different organ systems as well as related disease pathogenesis in an attempt to clarify the potential harms that may arise in COVID-19 patients receiving dexamethasone treatment. Overall, taking the threat of COVID­19 pandemic into account, we think it is necessary to apply dexamethasone as a pharmaceutical therapy in critical patients. However, its adverse side effects cannot be ignored. Our review will help medical professionals in the prognosis and follow-up of patients treated with dexamethasone. In addition, given that a considerable amount of uncertainty, confusion and even controversy still exist, further studies and more clinical trials are urgently needed to improve our understanding of the parameters and the effects of dexamethasone on patients with SARS-CoV-2 infection.

Technical note: fluorescein as an indicator of enteric mucosal barrier function in preruminant lambs

Increased intestinal permeability can be observed during the physiologic stress response and has been linked to suppression of animal health and performance. Previously published data have shown the efficacy of fluorescein isothiocyanate dextran (FITC-d; 4.17 mg/kg) as a marker of enteric inflammation and mucosal barrier function in multiple species. Fluorescein is a smaller, less expensive alternative molecule possessing similar properties. The following two experiments compared FITC-d and fluorescein as potential indicators of intestinal permeability in pre- and postweaned lambs administered daily intramuscular injections of dexamethasone (Dex; 0.1 mg/kg) for 1 wk. Experiment 1 consisted of five preweaned lambs that were placed in one of two treatment groups: fluorescein with Dex (F+Dex) or fluorescein only (F). On day 7, blood was collected before and 1 h after oral administration of fluorescein (50 mg/kg). Experiment 2 included 12 weaned lambs and four treatment groups: F+Dex, F, FITC-d with Dex (Fd+Dex), and FITC-d only (Fd). On day 7, blood was collected before and 2 h after oral administration of FITC-d (4.17 mg/kg) or fluorescein (50 mg/kg). Plasma fluorescence was reported as the ratio between T1h/T0 or T2h/T0 for experiment 1 or 2, respectively. Experiment 1 showed a significant increase in T1h/T0 ratio of F+Dex relative to F lambs (P = 0.05) indicative of increased leaky gut; however, no differences (P = 0.22) were obtained in experiment 2. Results of these experiments suggest fluorescein may serve as a suitable marker of enteric permeability in preruminant lambs, but not in those with functional rumens.

Clinical, clinicopathologic, and gastrointestinal changes from administration of clopidogrel, prednisone, or combination in healthy dogs: A double-blind randomized trial

Background

Dogs with immune‐mediated disease often receive glucocorticoids with clopidogrel, but ulcerogenic effects of current protocols are unknown.

Hypothesis/Objectives

To compare gastrointestinal endoscopic findings among dogs administered clopidogrel, prednisone, and combination treatment.

Animals

Twenty‐four healthy research dogs.

Methods

Double‐blinded, placebo‐controlled randomized trial. Dogs received placebo, clopidogrel (2–3 mg/kg q24h), prednisone (2 mg/kg q24h), or prednisone with clopidogrel PO for 28 days. Attitude, food intake, vomiting, and fecal score were determined daily. Clinicopathologic testing was performed at baseline and on day 28. Gastrointestinal hemorrhages, erosions, and ulcers were numerated by 2 blinded investigators for endoscopies performed on days 0, 14, and 28, and endoscopic mucosal lesion scores were calculated. Results were compared using mixed model, split‐plot repeated measures ANOVAs and generalized estimating equation proportional odds models as appropriate. P < .05 was considered significant.

Results

Clinical signs of gastrointestinal bleeding were not noted. Endoscopic mucosal lesion scores differed significantly by group (F[3, 20] = 12.8, P < .001) and time (F[2, 40] = 8.3, P < .001). Posthoc analysis revealed higher lesion scores in the prednisone‐receiving groups (P ≤ .006 for each) and on day 14 (P ≤ .007 for each). Ulcers were identified in 4 dogs administered prednisone and 3 dogs administered prednisone/clopidogrel. Odds of having endoscopic mucosal lesion scores ≥4 were 7‐times higher for dogs in prednisone (95%CI 1.1, 43.0; P = .037) and prednisone‐clopidogrel (95%CI 1.1, 43.4; P = .037) groups than those in the placebo group.

Conclusions and Clinical Importance

Gastrointestinal bleeding and ulceration occur commonly in healthy dogs administered prednisone or prednisone/clopidogrel treatment, but not clopidogrel monotherapy. Though lesions are severe in many cases, they are not accompanied by clinical signs.

Clinical, clinicopathologic, and gastrointestinal changes from aspirin, prednisone, or combination treatment in healthy research dogs: A double-blind randomized trial

Background

Dogs with immune‐mediated disease are often coadministered glucocorticoids and aspirin, but ulcerogenic effects of current protocols are unknown.

Objectives

To compare gastrointestinal changes among dogs administered aspirin, prednisone, and combination treatment.

Animals

Twenty‐four healthy research dogs.

Methods

Double‐blinded, placebo‐controlled randomized trial of dogs administered placebo, aspirin (2 mg/kg q24h), prednisone (2 mg/kg q24h), or combination treatment PO for 28 days. Clinical signs were recorded daily, with laboratory work performed at baseline and day 28. Gastrointestinal mucosal hemorrhages, erosions, and ulcers were numerated for endoscopic studies performed on days 0, 14, and 28; endoscopic mucosal lesion scores were calculated. Results were compared using mixed model repeated‐measures analyses of variance and generalized estimating equation proportional odds models. P < .05 was considered significant.

Results

Gastric mucosal lesion scores differed by treatment‐by‐time (F[6, 40] = 4.4, P = .002), treatment (F[3, 20] = 7.1, P = .002), and time (F[2, 40] = 18.9, P < .001). Post hoc analysis revealed increased scores in the aspirin (day 14 only), prednisone, and prednisone/aspirin groups during treatment. Ulcers were identified on 14 studies, representing 10 dogs. Dogs receiving prednisone and prednisone/aspirin had 11.1 times (95% CI, 1.7‐73.6) and 31.5 times (95% CI, 3.5‐288.0) higher odds, respectively, of having endoscopic mucosal lesion scores ≥4 than dogs receiving placebo (P ≤ .01).

Conclusions and Clinical Importance

Gastrointestinal bleeding occurs commonly in dogs administered aspirin, prednisone, or prednisone/aspirin treatment, with higher lesion scores for dogs receiving combination treatment. Even severe lesions are not accompanied by clinical signs.

The prevalence of endoscopic gastric mucosal damage in patients with rheumatoid arthritis

OBJECTIVES

Rheumatoid arthritis (RA) patients often take non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroids as supportive drugs. In this study, we investigated the prevalence of endoscopic gastric damage and their prescribed medications under an actual clinical condition.

METHODS

We collected the data of 1704 RA patients who underwent upper gastrointestinal fiberscopy. Gastric mucosal erosion and ulcer were classified using modified LANZA score. We analyzed these data with a multiple regression analysis.

RESULTS

The prevalence of endoscopic gastric mucosal damage in these RA patients was 16.7% (285 cases). A multiple regression analysis indicated that prednisolone (PSL), NSAIDs and proton pump inhibitors (PPIs) were independent risk factors associated with the modified LANZA score. PSL and NSAIDs were positively correlated with the score, while the administration of PPIs was inversely correlated with the score. The modified LANZA score in RA patients treated with both PSL and NSAIDs was significantly higher than that in those treated with PSL alone (no NSAIDs use).

CONCLUSIONS

Our findings suggest that PSL and NSAIDs were exacerbating factors for gastric mucosal damage, while PPIs usage was a protective factor. And, the combined usage of corticosteroids and NSAIDs may induce the development of gastric ulcers.

Immunosuppressive agents are associated with peptic ulcer bleeding

Peptic ulcer bleeding can be fatal. Non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids and immunosuppressive agents are administered for long-term usage. The present study assessed the association between peptic ulcer bleeding and administration of NSAIDs, corticosteroids and immunosuppressive agents. Furthermore, the efficacy of lowering the risk of peptic ulcer bleeding with proton pump inhibitors (PPI) and histamine 2 receptor antagonists (H2RA) was evaluated. Medical records were retrospectively analyzed for patients subjected to an upper gastrointestinal (GI) endoscopy performed at the National Hospital Organization Shimoshizu Hospital (Yotsukaido, Japan) from October 2014 to September 2015. During this period, a total of 1,023 patients underwent an upper GI endoscopy. A total of 1,023 patients, including 431 males (age, 68.1±12.9 years) and 592 females (age, 66.4±12.3 years), who had been administered NSAIDs, corticosteroids, immunosuppressive agents, PPIs and H2RAs, were respectively enrolled. Endoscopic findings of the patients were reviewed and their data were statistically analyzed. Logistic regression analysis was used to determine the odds ratio of peptic ulcer bleeding for each medication; immunosuppressive agents had an odds ratio of 5.83, which was larger than that for NSAIDs (4.77). The Wald test was applied to confirm the correlation between immunosuppressive agents and peptic ulcer bleeding. Furthermore, χ² tests were applied to the correlation between peptic ulcer bleeding and administration of PPIs or H2RAs. Immunosuppressive agents had the largest χ², and the P-value was 0.03. Administration of PPIs was significantly correlated with non-peptic ulcer bleeding (P=0.02); furthermore, a tendency toward non-peptic ulcer bleeding with administration of H2RA was indicated, but it was not statistically significant (P=0.12). In conclusion, immunosuppressive agents were correlated with peptic ulcer bleeding and PPIs were effective at lowering the risk of peptic ulcer bleeding.

Gastroprotective effects of montelukast and Nigella sativa oil against corticosteroid-induced gastric damage: they are much more than antiasthmatic drugs

Corticosteroids are used to treat a variety of diseases like bronchial asthma. However, long-term corticosteroids have a gastric ulcerogenic potential. Montelukast (MTK) and Nigella sativa oil (NSO) are used in treatment of bronchial asthma. Previous studies showed that MTK and NSO had gastroprotective effects in other models of gastric ulcer. The present study assesses synergistic gastroprotective effects of both drugs in dexamethasone (DXM)-induced gastric damage. Fifty male rats were divided into 5 groups: normal control (I), DXM group (II), MTK + DXM group (III), NSO + DXM group (IV), MTK + NSO + DXM group (V). After 7 days, stomachs were removed for biochemical analysis and histological examinations. Significant increases in malondialdehyde (MDA) level, superoxide dismutase (SOD) activity, myeloperoxidase (MPO) activity, and proliferating cell nuclear antigen (PCNA) positive cells, with significant decreases in mucus secretion were detected in DXM-treated group compared with group I. Meanwhile, significant decreases of MDA level, MPO activity, and PCNA positive cells and significant increases in mucus secretion were detected in treated groups compared with group II. SOD activity significantly decreased in group V compared with group II. We could conclude that administration of either MTK or NSO or both with DXM counteracts DXM-induced gastric lesions.

Percutaneous Epidural Adhesiolysis with Epidural Steroid Injection: A Non-inferiority Test of Non-particulate Steroids Versus Particulate Steroids

OBJECTIVES

To evaluate the efficacy of dexamethasone sodium phosphate (DSP), a non-particulate steroid, during percutaneous epidural adhesiolysis (PEA), as compared with triamcinolone acetate (TA).

DESIGN

Retrospective observational study.

SETTING

Interventional pain management clinic in a tertiary care center.

SUBJECTS

Patients scheduled to receive PEA between March 2011 and January 2014.

METHODS

47 patients underwent the procedure with TA (TA group), and 26 patients underwent the procedure with DSP (DSP group). At the end of the procedure, 20 ml of 0.18% ropivacaine containing 3000 units of hyaluronidase and 80 mg of TA or 10 mg of DSP was injected. Success rates and means of percent decreases in terms of verbal numerical rating scale (VNRS) of pain and Oswestry Disability Index (ODI) at follow-up visits 3 and 6 months after PEA were compared. Non-inferiority test was used for statistical analysis.

RESULTS

At 3 months, the success rate in VNRS of TA group and DSP group were 59.6% and 53.8%. The mean percent decreases of VNRS were 42.4% and 46.1% in TA group and DSP group, respectively. At this time point, non-inferiority was not demonstrated. In contrast at 6 months, the success rate in aspect of VNRS was 45.2% in TA group and 62.5% in DSP group. The mean of percent decreases in the VNRS was 34.9% in TA group and 52.8% in DSP group. The non-inferiority was met in two measurements.

CONCLUSIONS

DSP presents non-inferiority to TA in terms of success rate and percentage decrease of the VNRS 6 months after PEA.

Short-term use of glucocorticoids and risk of peptic ulcer bleeding: a nationwide population-based case-crossover study

BACKGROUND

Controversy exists regarding glucocorticoids therapy and the risk of peptic ulcer bleeding (PUB).

AIM

The present study was undertaken to determine whether short-term use of glucocorticoids is associated with the occurrence of peptic ulcer bleeding.

METHODS

The records of adult patients hospitalised for newly diagnosed peptic ulcer bleeding from 2000 to 2012 were retrieved from the Taiwan National Health Insurance Research Database, a nationwide population-based registry system. The association between systemic glucocorticoids usage and peptic ulcer bleeding was determined with a conditional logistic regression model comparing cases and controls during time windows of 7, 14 and 28 days using a case-crossover design.

RESULTS

Of the 8894 enrolled patients, the adjusted self-matched odds ratios for peptic ulcer bleeding after exposure to the glucocorticoids were 1.37 (95% CI: 1.12-1.68, P = 0.003) for the 7-day window, 1.66 (95% CI: 1.38-2.00, P < 0.001) for the 14-day window and 1.84 (95% CI: 1.57-2.16, P < 0.001) for the 28-day window. Moderate to high, but not low dose glucocorticoids (methylprednisolone <4 mg/day or its equivalence) were associated with an increased risk of peptic ulcer bleeding. Concomitant use of a nonselective nonsteroidal anti-inflammatory drug (NSAID) or aspirin further elevated the risk. However, it does not eliminate the effect of underlying diseases flare-up that may have placed the patients at risk for peptic ulcer bleeding in this kind of study design.

CONCLUSIONS

Short-term (7-28 days) exposure to glucocorticoids is significantly associated with peptic ulcer bleeding; this risk seems dose-dependent and is higher when nonselective NSAIDs or aspirin are used concurrently.

Dexamethasone altered steroidogenesis and changed redox status of granulosa cells

Glucocorticoids have been widely used in clinical application for anti-inflammatory and immunosuppressive function. Previous study reported that glucocorticoids adversely affect the reproductive system and can directly act on ovary. Here, we found that progesterone production induced by dexamethasone requiring activation of caspase-3 which may mediate differentiation and apoptosis of granulosa cells. Further study displayed that cellular glutathione level was increased and reactive oxygen species was decreased accompanied with unchanged mitochondrial membrane potential which may contribute to the maintenance of steroidogenesis in granulosa cells treated with dexamethasone. Dexamethasone also augmented the level of anti-Müllerian hormone secreted by preovulatory granulosa cells which indicated that dexamethasone may promote preantral follicles development.

Inhibitory effects of a β-dunnione compound MB12662 on gastric secretion and ulcers

The effects of a β-dunnione compound MB12662 on the gastric secretion and ulcers were investigated in rats. In order to assess the effects of MB12662 on the gastric secretion and acidity, rats were subjected to pylorus ligation operation, and 6 hours later, gastric fluid was collected. Treatment with MB12662 reduced the gastric fluid volume to 47.3% of control level and increased pH. In an alcohol-induced ulcer model, rats were orally administered 3 mL/kg of ethanol, and 1 hour later, the ulcer lesions ware measured under a stereomicroscope. MB12662 reduced ulcer index in a dose-dependent manner which was much stronger than a proton-pump inhibitor pantoprazole. In a stress-induced ulcer model, rats were subjected to water-immersion restraint stress, and 5 hours later, the ulcer lesions ware examined. MB12662 also attenuated the stress-induced gastric lesions, although the efficacy of MB12662 was lower than that of pantoprazole. Therefore, it is suggested that MB12662 could be a candidate compound for the prevention or treatment of gastric ulcers induced by gastric over-secretion and alcoholic hangover.

Tissue-specific actions of glucocorticoids on apoptosis: a double-edged sword

First described for their metabolic and immunosuppressive effects, glucocorticoids are widely prescribed in clinical settings of inflammation. However, glucocorticoids are also potent inducers of apoptosis in many cell types and tissues. This review will focus on the established mechanisms of glucocorticoid-induced apoptosis and outline what is known about the apoptotic response in cells and tissues of the body after exposure to glucocorticoids. Glucocorticoid-induced apoptosis affects the skeletal system, muscular system, circulatory system, nervous system, endocrine system, reproductive system, and the immune system. Interestingly, several cell types have an anti-apoptotic response to glucocorticoids that is cytoprotective. Lastly, we will discuss the pro- and anti-apoptotic effects of glucocorticoids in cancers and their clinical implications.

Glucocorticoids are Gastroprotective under Physiologic Conditions

Stress may contribute to the development and progression of gastrointestinal disorders. Activation of the hypothalamic-pituitary-adrenocortical (HPA) axis is one of the main characteristics of stress. For several decades it was generally accepted that glucocorticoids released during stress are ulcerogenic hormones. We designed some experimental studies in rats to clarify the validity of this widely held view. To achieve this goal, we examined the effect of glucocorticoid deficiency followed by corticosterone replacement or the glucocorticoid receptor antagonist, RU-38486, on stress-induced gastric erosion and the parameters of gastric function in rats. The data obtained shows that the reduction in the stress-induced corticosterone release, or its actions, aggravates stress-caused gastric erosion. It is suggested that an acute increase in corticosterone during stress protects the stomach against stress-induced injury. According to our results, various ulcerogenic stimuli, similar to stress, induce an increase in corticosterone that helps the gastric mucosa to resist against a harmful action of ulcerogenic stimuli. Glucocorticoids exhibit their gastroprotective effect by both maintaining local defensive factors and inhibiting pathogenic elements. Furthermore, the contribution of glucocorticoids to gastroprotection is tightly related to their contribution to general body homeostasis. Glucocorticoids provide gastroprotective actions in co-operation with prosta-glandins, nitric oxide and capsaicin-sensitive sensory neurons. The results obtained do not support the traditional paradigm and suggest that glucocorticoids released during acute activation of the HPA axis are naturally occurring gastroprotective factors. In this article, we review our recent publications on the role of glucocorticoids in gastroprotection.

Influence of proton pump inhibitors on dexamethasone-induced gastric mucosal damage in rats

The present study was designed to compare the curative role of proton pump inhibitors, omeprazole, rabeprazole and lansoprazole against dexamethasone-induced ulcer model. Dexamethasone (5 mg/kg/day) was used as an ulcerogen. Dexamethasone suspended in 1% CMC in water was given orally to all rats. Omeprazole (20 mg/kg), rabeprazole (20 mg/kg), and lansoprazole (20 mg/kg) were administered by oral route 30 minutes prior to dexamethasone for ulcer protective studies, gastric secretion and mucosal studies. Effects of proton pump inhibitors were determined by the evaluation of various biochemical parameters such as estimation of myeloperoxidase, cortisol, alkaline phosphatase, malondialdehyde, endogenous anti-oxidants like superoxide dismutase, catalase and reduced glutathione. In dexamethasone induced ulcer model, omeprazole showed significant decrease in malondialdehyde, myeloperoxidase, alkaline phosphatase level and increase in superoxide dismutase, catalase and reduced glutathione level as compared to rabeprazole and lansoprazole. Omeprazole showed significant reduction in cortisol content where as rabeprazole and lansoprazole did not show significant changes as compared to control. The result indicates that omeprazole is the most effective and selective proton pump inhibitor in dexamethasone induced ulcer model as compared to rabeprazole and lansoprazole.

Drug-induced acute liver failure and gastrointestinal complications

The objective of this article is to describe adverse drug events related to the liver and gastrointestinal tract in critically ill patients. PubMed and other resources were used to identify information related to drug-induced acute liver failure, gastrointestinal hypomotility, constipation, diarrhea, gastrointestinal bleeding, and pancreatitis in critically ill patients. This information was reviewed, and data regarding pathophysiology, common drug causes, and guidelines for prevention and management were collected and summarized. In cases in which data in critically ill patients were unavailable, data were extrapolated from other patient populations. Drug-induced acute liver failure can be caused by many drugs routinely used in the intensive care unit and may be associated with significant morbidity and mortality. Drug-related hypomotility and constipation and drug-related diarrhea are reported with many drugs, and these are common adverse drug events in critically ill patients that can substantially complicate the care of these patients. Drug-induced gastrointestinal bleeding and drug-induced pancreatitis occur less frequently, can range in disease severity, and can be associated with morbidity and mortality. Many drugs used in critically ill patients are associated with adverse drug events related to the liver and gastrointestinal tract. Critical care clinicians should be aware of common drug causes of drug-induced acute liver failure, gastrointestinal hypomotility, constipation, diarrhea, gastrointestinal bleeding, and pancreatitis, and should be familiar with the prevention and management of these diverse conditions.

Nonsteroidal Anti-Inflammatory Drug-Induced Gastroduodenal Bleeding: Risk Factors and Prevention Strategies

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most widely prescribed medications in the World. A frequent complication of NSAID use is gastroduodenal bleeding. Risk factors for gastroduodenal bleeding while on NSAID therapy are age, prior peptic ulcer and co-medication with anti-platelet agents, anticoagulants, glucocorticosteroids and selective serotonin-reuptake inhibitors (SSRI). Prevention strategies for at-risk patients include the use of the lowest effective dose of NSAIDs, co-therapy with proton-pump inhibitors and/or the use of a COX-2 selective agent. Treatment of Helicobacter pylori infection is beneficial for primary prophylaxis of NSAID-induced gastroduodenal bleeding in NSAID-naive patients. For patients with cardiovascular risk factors requiring NSAIDs, naproxen should be selected. In very high risk patients for both gastrointestinal and cardiovascular complications NSAID therapy should be avoided altogether.

Comparative study of proton pump inhibitors on dexamethasone plus pylorus ligation induced ulcer model in rats

The present study was designed to compare ulcer protective effect of proton pump inhibitors viz. omeprazole, rabeprazole and lansoprazole against dexamethasone plus pylorus ligation induced ulcer model. Dexamethasone (5 mg/kg) was used as an ulcerogen. Dexamethasone suspended in 1% CMC in water was given orally to all the rats 15 min after the pylorus ligation. Omeprazole (20 mg/kg), rabeprazole (20 mg/kg), and lansoprazole (20 mg/kg) were administered by oral route 30 min prior to ligation was used for ulcer protective studies, gastric secretion and mucosal studies. Effects of proton pump inhibitors were determined by the evaluation of various biochemical parameters such as ulcer index, free and total acidity, gastric pH, mucin, pepsin and total proteins. Oral administration of proton pump inhibitors showed significant reduction in gastric acid secretion and ulcer protective activity against dexamethasone plus pylorus ligation induced ulcer model. The % protection of omeprazole, rabeprazole and lansoprazole was 84.04, 89.36 and 79.78, respectively. Rabeprazole significantly inhibited the acid-pepsin secretion and increased the gastric mucin secretion. The observations made in the present study suggest that rabeprazole is the most effective gastric antisecretory and ulcer healing agent as compared to omeprazole and lansoprazole.

Gastric mucosal injury in systemic lupus erythematosus patients receiving pulse methylprednisolone therapy

AIMS

Whether glucocorticoids induce gastric mucosal injury remains uncertain. We investigated whether very high-dose steroids caused gastric mucosal injury in systemic lupus erythematous (SLE) patients and evaluated the possible risk factors for mucosal injury.

METHODS

In this prospective paired study, 67 SLE patients who had received pulse methylprednisolone therapy were enrolled. Each patient underwent endoscopic examination and tissue and blood sampling before and after pulse steroid therapy. Mucosal injury was diagnosed if the follow-up injury scale was higher than the initial scale. Examined parameters included Helicobacter pylori infection, cyclooxygenase (COX)-1 and COX-2 activity, and current nonsteroidal anti-inflammatory drug (NSAID) usage including aspirin.

RESULTS

Eleven (16.4%) of 67 cases who developed gastric mucosal injury after pulse therapy had significantly higher rates of peptic ulcer history, NSAID/aspirin use, lower gastric thromboxane B(2) and prostaglandin E(2) levels when compared with cases without gastric mucosal injury (P < 0.05). Infection by H. pylori was not a risk factor for gastric mucosal injury. Multivariate logistic regression analysis showed that NSAID/aspirin use was the only risk factor for gastric mucosal injury in these patients (odds ratio 26.99, 95% confidence interval 4.91, 148.57, P < 0.0001). Pulse steroid therapy alone did not induce gastric mucosal injury in fifty SLE patients without taking any NSAID/aspirin.

CONCLUSIONS

Use of NSAIDs/aspirin, but not H. pylori infection, increases gastric mucosal injury in SLE patients receiving pulse methylprednisolone therapy. Very high-dose steroids de novo seem not to induce gastric mucosal injury in these patients. A larger case-controlled study enrolling a heterogeneous population is needed to clarify the role of glucocorticoids in gastric mucosal injury.

PI3 Kinase Dependent Stimulation of Gastric Acid Secretion by Dexamethasone

Excessive gastric acid secretion plays an important role in the pathogenesis of peptic ulcers. Dexamethasone, a widely used drug, is known to stimulate gastric acid secretion and increase the incidence of peptic ulcers. However little is known about the mechanism of the dexamethasone's effect on parietal cells. The present study was performed to investigate the contribution of the phosphatidylinositol-3-kinase (PI3 kinase) to dexamethasone induced stimulation of gastric acid secretion. In vivo pretreatment with dexamethasone injections (150 microg/100g for 3 days) or in vitro exposure to (10 microM for > 20 minutes) significantly increased acid secretion in isolated gastric glands approximately 2-3 fold. The dexamethasone induced stimulation of gastric acid secretion was concentration dependent and significantly blunted by the H+/K2+ ATPase inhibitor omeprazole (200 microM), the PI3 kinase inhibitor Wortmannin (500 nM), the protein kinase inhibitor staurosporine (2.5 microM) and the Cl(-) channel blocker NPPB (100 microM); but not by the H(2) antagonist cimetidine (100 microM). In conclusion, it was observed that dexamethasone's effect on proton extrusion requires the activity of a PI3 kinase pathway, an apical Cl(-) channel and the H2+/K2+ ATPase.

Role of the serum and glucocorticoid inducible kinase SGK1 in glucocorticoid stimulation of gastric acid secretion

Glucocorticoids stimulate gastric acid secretion, an effect favoring the development of peptic ulcers. Putative mechanisms involved include the serum- and glucocorticoid-inducible kinase (SGK1), which stimulates a variety of epithelial channels and transporters. The present study explored the contribution of SGK1 to effects of glucocorticoids on gastric acid secretion. In isolated gastric glands from gene-targeted mice lacking functional SGK1 (sgk1 (-/-)) and their wild-type littermates (sgk1 (+/+)), H(+)-secretion (DeltapH/min) was determined utilizing 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein (BCECF)-fluorescence, SGK1 transcript levels by in situ hybdridization, and expression of KCNQ1 channels by immunohistochemistry and real-time polymerase chain reaction. SGK1 transcript levels were enhanced by a 4-day treatment with 10 mug/g body weight (BW)/day dexamethasone (DEX). Before treatment, DeltapH/min was similar in sgk1 (-/-) and sgk1 (+/+)mice. DEX increased DeltapH/min approximately fourfold in sgk1 (+/+)mice and approximately twofold in sgk1 (-/-)mice, effects abolished in the presence of K(+)/H(+)ATPase-inhibitor omeprazole (50 microM). Increase in local K(+) concentrations to 35 mM (replacing Na(+)) enhanced DeltapH/min, which could not be further stimulated by DEX and was not significantly different between sgk1 (-/-) and sgk1 (+/+)mice. Carbachol (100 microM) and forskolin (5 microM) stimulated gastric acid secretion to a similar extent in sgk1 (-/-) and sgk1 (+/+)mice. In conclusion, SGK1 is not required for basal and cyclic AMP-stimulated gastric H(+) secretion but participates in the stimulation of gastric H(+) secretion by glucocorticoids. The effects of glucocorticoids and SGK1 are not additive to an increase in extracellular K(+) concentration and may thus involve stimulation of K(+) channels.

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Non-ulcerogenic dose of dexamethasone delays gastric ulcer healing in rats

Although the ulcerogenic action of corticosteroids in the stomach is controversial, its action on ulcer healing has not been defined. In this study, we used non-ulcerogenic doses of dexamethasone (0.1 or 0.2 mg/kg/day) to explore the adverse effect on ulcer healing as well as its pathological mechanisms in rat stomach. In this regard, we measured ulcer size, mucus thickness, epithelial cell proliferation and apoptosis, and angiogenesis at the ulcer site at different time points after ulcer induction. Protein expressions of cyclooxygenase-1 and -2 (COX-1 and COX-2) and cytosolic phospholipase A2 (cPLA2) over the ulcer margin were evaluated, and the mucosal prostaglandin E2 (PGE2) level was also determined. Dexamethasone treatment in the current doses did not produce mucosal damage in intact animals. However, the drug dose-dependently delayed gastric ulcer healing. It also decreased mucus content and epithelial cell proliferation at the ulcer margin as well as angiogenesis at the ulcer margin and base. These were associated with a significant decrease of COX-2 expression and PGE2 level but not COX-1 at the ulcer margin. The drug only marginally reduced the cPLA2 expression without affecting the apoptosis at the ulcer margin. PGE2 treatment reversed the adverse effects of dexamethasone on ulcer healing. It is concluded that nonulcerogenic doses of dexamethasone can delay ulcer repair via depression of COX-2 expression and PGE2 formation in the gastric mucosa.

Chemical and instrumental approaches to treat hyperpigmentation

Many modalities of treatment for acquired skin hyperpigmentation are available including chemical agents or physical therapies, but none are completely satisfactory. Depigmenting compounds should act selectively on hyperactivated melanocytes, without short- or long-term side-effects, and induce a permanent removal of undesired pigment. Since 1961 hydroquinone, a tyrosinase inhibitor, has been introduced and its therapeutic efficacy demonstrated, and other whitening agents specifically acting on tyrosinase by different mechanisms have been proposed. Compounds with depigmenting activity are now numerous and the classification of molecules, based on their mechanism of action, has become difficult. Systematic studies to assess both the efficacy and the safety of such molecules are necessary. Moreover, the evidence that bleaching compounds are fairly ineffective on dermal accumulation of melanin has prompted investigations on the effectiveness of physical therapies, such as lasers. This review which describes the different approaches to obtain depigmentation, suggests a classification of whitening molecules on the basis of the mechanism by which they interfere with melanogenesis, and confirms the necessity to apply standardized protocols to evaluate depigmenting treatments.

Peroxidase-mediated mechanisms are involved in the melanocytotoxic and melanogenesis-inhibiting effects of chemical agents

Melanogenesis is based on the enzymatic conversion of the amino acid tyrosine, through a series of intermediates, to melanin pigments. The nature of the enzymes involved in the different steps of melanogenesis has been intensely debated. However, it is now believed that tyrosinase is responsible for the conversion of tyrosine to dopa and of dopa to dopaquinone, and that peroxidase accomplishes the oxidative polymerization of the eventually formed indoles to eumelanin pigments. Some very few investigators have also considered a main role for peroxidase in initiating melanogenesis. At present, most different hypotheses are focused on tyrosinase-mediated mechanisms to elucidate the melanocytotoxic and depigmenting activities of chemicals. However, many properties of these agents cannot be explained by such mechanisms. Most of the melanocytotoxic agents (e.g. hydroquinone, catechols, butylated hydroxyanisole) can be converted to cytotoxic species, such as quinones, by the peroxidase-H(2)O(2) system. On the other hand, many of the melanogenesis inhibitors which are not known to inhibit tyrosinase (e.g. glucocorticoids, ascorbic acid, indomethacin) have the capacity to strongly inhibit peroxidase activity. We have proposed that peroxidase-mediated mechanisms, in addition to or in several instances rather than tyrosinase-mediated mechanisms, can explain the melanocytotoxic and depigmenting properties of such agents.