COX-2 inhibitors vs. NSAIDs in gastrointestinal damage and prevention

An Insilico evaluation of phytocompounds from Albizia amara and Phyla nodiflora as cyclooxygenase-2 enzyme inhibitors

PURPOSE

The enzyme Cyclooxygenases (COX-1 and COX-2) catalyze the formation of prostaglandin, a mediator of the inflammatory pathway. Inflammation related pathological conditions may be alleviated by targeting the Cox enzymes.COX-2 inhibitors that are currently available in the market causes undesirable side effects. Our present study focuses on the in-silico inhibition of COX -2 enzyme by the phytocompounds from Albizia amara and Phyla nodiflora.

METHODS

The phytochemicals present in Albizia amara and Phyla nodiflora were analyzed for their COX-2 inhibition potential. Eight compounds from Albizia amara and eleven compounds from Phyla nodiflora obtained from GC-MS analysis was used for the current study. Molecular docking was performed using AutoDock vina. The crystal structure of COX-2 (PDB ID: 5IKR) was obtained from Protein data bank. PyMol was used to remove any solvent, organic and inorganic molecules. Energy minimization of the protein was carried out using SPDBV software. Geometrical optimizations of the ligands were performed using Avogadro software. Celecoxib was used as the positive control. ADMET properties of the compounds were analyzed using SwissADME and ProtoxII online servers. Molecular mechanics/generalized born surface area (MM/GBSA) calculations were performed to evaluate the binding efficiency. Molecular dynamics of the protein and protein-ligand complex was studied for about 100 ns using Desmond package of Schrodinger suite.

RESULTS

Among the eighteen compounds, Squalene present in both the plants showed a better binding energy of -7.7 kcal/mol, when compare to other phytocompounds present in the extract. The control celecoxib showed a binding energy of about - 9.4 kcal/mol. The toxicity and ADMET properties of squalene indicated that it is non-toxic and followed Lipinski's rule. Molecular Dynamics (MD) analysis showed that the binding of squalene to the enzyme was stable.

CONCLUSION

Squalene could potentially inhibit COX2 and o wing to its properties, squalene can be formulated in gels/creams and could be possibly used for external edema and inflammation.

Novel treatments for chronic pain: moving beyond opioids

It is essential that safe and effective treatment options be available to patients suffering from chronic pain. The emergence of an opioid epidemic has shaped public opinions and created stigmas surrounding the use of opioids for the management of pain. This reality, coupled with high risk of adverse effects from chronic opioid use, has led chronic pain patients and their healthcare providers to utilize nonopioid treatment approaches. In this review, we will explore a number of cellular reorganizations that are associated with the development and progression of chronic pain. We will also discuss the safety and efficacy of opioid and nonopioid treatment options for chronic pain. Finally, we will review the evidence for adenylyl cyclase type 1 (AC1) as a novel target for the treatment of chronic pain.

Anti-inflammatory Effects and Mechanisms of Rhein, an Anthraquinone Compound, and Its Applications in Treating Arthritis: A Review

Inflammation is a defensive response of living tissues to damaging agents, which exists in two forms, acute inflammation and chronic inflammation, and chronic inflammation is closely related to arthritis. Currently, the commonly prescribed anti-inflammatory medications are greatly limited by high incidence of gastrointestinal erosions in the clinical applications. Rhein, a bioactive constituent of anthraquinone, exhibits excellent anti-inflammatory activities and therapeutic effects on arthritis with less gastrointestinal damages. Although there are numbers of studies on anti-inflammatory effects and mechanisms of rhein in the last few decades, to the best of our knowledge, only a few review articles pay attention to the interactive relationships of rhein on multiple inflammatory signaling pathways and cellular processes from a comprehensive perspective. Herein, we summarized anti-inflammatory effects and mechanisms of rhein and its practical applications in the treatment of arthritis, thereby providing a reference for its basic researches and clinical applications.

Successful closure of chronic recurrent Enterocutaneous fistula with a concurrent over-the-scope closure and a stent placement

Gastrointestinal ulcers and perforations can occur as a complication of nonsteroidal anti-inflammatory drugs (NSAID). Emerging endoscopic technologies can be utilized to successfully intervene perforations that fail surgical intervention. We report a case of perforated duodenal ulcer that failed surgical intervention and, however, was successfully closed with over-the-scope clip (OTSC) closure with concomitant placement of fully covered stent.

Analysis of risk factors for colonic diverticular bleeding and recurrence

The increase in incidence of colonic diverticular bleeding is relative to an age-related rise in the incidence of colonic diverticulosis and use of antithrombotic medication. However, risk factors related to the onset, recurrence, and prophylaxis have not been established. Therefore, we aimed to determine risk factors for the onset and recurrence of colonic diverticular bleeding.An age- and sex-matched case-control study was performed to assess the risk factors for the onset of colonic diverticular bleeding. The distribution of diverticulosis, comorbidity, and medication were evaluated from medical records. We also assigned patients with a first-time bleeding into groups with and without rebleeding during follow-up to determine risk factors for recurrence.Bilateral colonic diverticulosis, nonselective nonsteroidal anti-inflammatory drugs (NSAIDs), low-dose aspirin (LDA), and anticoagulants were significant risk factors for the onset of colonic diverticular bleeding on multivariate analysis. In contrast, the use of selective cyclooxygenase-2 (COX-2) inhibitor was not a risk factor for the onset. The incidence of bleeding in direct oral anticoagulant and warfarin users was not different between the 2 groups. The cumulative recurrence rate at 1 year was 15%. Recurrence rate was significantly higher in patients with a prior history of colonic diverticular bleeding than those without. Steroid use was associated with recurrence.Extensive distribution of diverticulosis and use of nonselective NSAIDs, LDA, and anticoagulants are regarded as risk factors for the onset of colonic diverticular bleeding. In addition, a prior history of colonic diverticular bleeding is related to the recurrence.

Synthesis of benzo[d]thiazole-hydrazone analogues: molecular docking and SAR studies of potential H+/K+ ATPase inhibitors and anti-inflammatory agents

A series of new benzo[d]thiazole-hydrazones were synthesized and characterized by analytical and spectroscopic techniques. All the compounds were screened for their in vitro inhibition of H⁺/K⁺ ATPase and anti-inflammatory effects. The results revealed that compounds 6-8, 13-15, 18-20, 22, 23 and 27-30 displayed excellent inhibitory activity against H⁺/K⁺ ATPase, and their IC₅₀ values were lower than those of the standard compound omeprazole. Compounds 2-5, 9-12, 28 and 30 exhibited better anti-inflammatory activity in comparison to the standard compound indomethacin. Studies of the structure-activity relationship (SAR) showed that electron-donating groups (OH and OCH₃) favored inhibitory activity against H⁺/K⁺ ATPase, whereas electron-withdrawing groups (F, Cl, Br and NO₂) favored anti-inflammatory activity, and derivatives with both electron-donating (OH and OCH₃) and electron-withdrawing (Br) groups (16-18) displayed reasonable activity, whereas aliphatic analogues (24-26) exhibited less activity and heterocyclic analogues (27-30) displayed moderate activity in both biological studies. Molecular docking studies were performed for all the synthesized compounds, among which compounds 19 and 20 exhibited the highest docking scores for inhibitory activity against H⁺/K⁺ ATPase, whereas compounds 10 and 12 displayed the highest docking scores for anti-inflammatory activity.

An overview of history, pathogenesis and treatment of perforated peptic ulcer disease with evaluation of prognostic scoring in adults

Peptic ulcer disease including both gastric and duodenal ulcer form a substantial part of patients seeking surgical opinion world-wide. The concept of acid in peptic ulcer disease, which was the basis of treatment of peptic ulcer was revolutionized by the discovery of H₂-receptor antagonists, that led to the principle of acid suppression therapy for duodenal ulcer which followed decades of preference for surgical interventions in the form of gastric resections, vagotomy etc., After the discovery of Helicobacter pylori organism as the causative factor a triple drug regime was identified to treat peptic disease which was further modified to sequential therapy to avoid antibiotic resistance. This recognition has not concluded the chapter on peptic ulcers. The management of ulcer disease and its complications remain a surgical challenge. All the materials for this review have been accessed from various internet search engines. The references have been narrowed down to 34 by excluding cross references, duplicated citations, pediatric studies, case reports, iatrogenic and malignant perforations and including microbiological, immunohistochemistry references and studies with more than a sample size of ten. Case control, cohort studies, prospective/retrospective, metaanalytical studies were preferred in that order. This article attempts to take an overview of all aspects of the management of peptic ulcer.

Metformin use is associated with a decreased incidence of colorectal adenomas in diabetic patients with previous colorectal cancer

BACKGROUND

Metformin use has been associated with decreased cancer risk and mortality. However, the effects of metformin on the development of colorectal adenomas, the precursors of colorectal cancers, are not defined.

AIMS

This study aimed to evaluate the potential effect of metformin on the incidence of colorectal adenomas in diabetic patients with previous colorectal cancer.

METHODS

Among 488 consecutive diabetic patients who underwent colonoscopic surveillance after curative resection of colorectal cancer between 1998 and 2008, 240 patients were enrolled in this study and were compared in two groups: 114 patients taking metformin and 126 patients not taking metformin. Patient demographics, clinical characteristics, and colorectal adenoma incidence rate were analysed.

RESULTS

After a median follow-up of 58 months, a total of 33 patients (28.9%) exhibited adenomatous colorectal polyps among the 114 patients who used metformin, compared with 58 (46.0%) patients with colorectal adenomas among the 126 patients who did not use metformin (odds ratio = 0.48, 95% confidence interval = 0.280-0.816, P = 0.008). After adjustment for clinically relevant factors, metformin use was found to be associated with a decreased incidence of colorectal adenomas (odds ratio = 0.27, 95% confidence interval = 0.100-0.758, P = 0.012) in diabetic patients with previous colorectal cancer. Metformin use in diabetic patients with previous colorectal cancer is associated with a lower risk of colorectal adenoma.

Colonic perforation after short-term use of nonsteroidal antiinflammatory drugs: report of two cases

Nonsteroidal antiinflammatory drugs are widely used for acute and chronic pain, but they may have serious side effects such as impairment of renal function, asthma, erosions of the mucosa in the gastrointestinal tract, colonic and intestinal strictures, and gastrointestinal tract bleeding. Although the upper gastrointestinal tract disturbances caused by nonsteroidal antiinflammatory drugs are well known, their side effects in the lower gastrointestinal tract are not clearly defined. There are a limited number of articles and case reports about the latter in the literature. We report two cases of colonic perforation due to short-term use of nonsteroidal antiinflammatory drugs in this study. Colonic perforation should be considered as one of the possible diagnoses in patients with acute abdominal pain and nonsteroidal antiinflammatory drug use should be considered as a possible cause of colonic perforation if other possibilities are excluded.

Upper gastrointestinal bleeding in haemophiliacs: incidence and relation to use of non-steroidal anti-inflammatory drugs

This multicentre study sought to estimate the incidence of upper gastrointestinal (UGI) bleeding in haemophiliacs and its relationship to use of non-steroidal anti-inflammatory drugs (NSAIDs). Cox models were used to estimate relative hazards (RH) with 95% confidence intervals (CI) for postulated risk factors. Conditional logistic regression and stored sera were used to assess UGI bleeding risk with Heliobacter pylori seropositivity in cases compared with closely matched controls. During a mean of 17.4 months (range 2-34), 2285 participants, ages 13-89 (mean 36.5) were followed for 3309 person-years (py). Forty-two experienced a UGI bleeding event (incidence 1.3 per 100 py), most from ulcer (11), gastritis (four), varices (five) and Mallory Weiss tears (eight). RH was significantly increased with traditional NSAID use for <1 month (OR: 3.66; 95% CI: 1.1-11.9), but not with coxibs use. RH was significantly and independently increased with age >46 years (3.5; 95% CI: 1.1-10.6) and hepatic decompensation (4.4; 95% CI: 1.7-11.6). Likelihood of bleeding was substantially but not significantly increased (OR: 4.6; 95% CI: 0.3-83.9) with H. pylori seropositivity. These findings suggest that coxibs are a safer alternative than traditional NSAIDs in the treatment of haemophilic arthropathy.

Chemoprevention for colon cancer: new opportunities, fact or fiction?

Colorectal cancer (CRC) is still a disease with a high incidence and mortality. Prevention of (pre-) cancerous lesions of CRC by endoscopic screening is promising, but costs are high and identification of high-risk populations is difficult. Since screening both average-risk and high-risk populations for CRC has its logistic and financial limitations, new primary prevention strategies are sought. Substantial evidence has shown that non-steroidal anti-inflammatory drugs (NSAIDs) and selective COX-2 inhibitors can reduce the incidence and mortality of CRC. However, long-term use of NSAIDs is associated with substantial gastrointestinal toxicity and may cause an exacerbation in IBD patients. Selective COX-2 inhibitors, with a better toxicity profile and no flare-up in IBD disease activity, are therefore attractive candidates for prevention. Chemoprevention with low-dose aspirin can be considered for individuals carrying a high risk for CRC. Folate supplementation is beneficial to the folate-depleted patients, since significant risk reductions for CRC are reported. Moreover, it might be applicable to the general population because it is safe, inexpensive and protects against vascular diseases. In line with drugs beneficial for multiple disease entities, statins have recently been proposed to reduce CRC risk. Ursodeoxycholic acid has been shown to decrease the incidence of colonic dysplasia in patients with ulcerative colitis and PSC and possibly reduces recurrence rates of polyps in general. Unfortunately, prospective randomized trials, in both high-risk and general population, are not available and the evidence is still controversial. Furthermore, cumulative epidemiological and observational data suggest the potential role of hormones as a chemoprotective agent. An increase in CRC in females with an early menopause, as well as a decrease of CRC in women with hormone replacement therapy justify further research into this issue. In IBD patients, both the severity and duration of the inflammation are the most evident risk factors for the development of dysplasia and subsequently cancer. Remission of inflammation, clinically, endoscopically and histologically, in IBD is the major goal. Long-term use of 5-aminosalicylates (5-ASA) has been shown to decrease the incidence of CRC and may hold the best promise as a chemoprotective agent in IBD. In parallel with primary prevention strategies in vascular medicine, the aim might be to postpone adenoma formation, for instance for 10 years, thereby achieving a significant risk reduction for CRC. In current practice, folate supplementation along with low-dose aspirin use in high-risk patients may be most attractive candidates, while future studies will have to clarify the role of these and other chemoprotective agents.

Proton pump inhibitor co-therapy normalizes the increased cell turnover of the gastric mucosa both in NSAID and selective COX-2 users

Proton pump inhibitor (PPI) co-therapy is considered the best strategy in preventing gastrointestinal complications during non-steroidal anti-inflammatory drug (NSAID) treatment, but there is limited information available on its effect on gastric mucosal cell kinetics. To evaluate the effect of PPI co-therapy on gastric mucosa we investigated epithelial cell proliferation, apoptosis, epithelial growth factor receptor (EGFR) and p53 expression in patients on chronic non-selective NSAID or cyclooxygenase-2 selective inhibitor (COX-2) treatment. Gastric biopsies of the antrum were taken from 10-10 patients on chronic NSAID and COX-2, therapy prior and after 6 months PPI co-therapy, and 10 controls without any treatment. Cell proliferation, apoptosis, EGFR and p53 expression were measured by immunohistochemistry. At least 600 glandular epithel cells were encountered and results were expressed as % of total cells counted. We found increased cell proliferation in patients on chronic COX-2 but not on NSAID therapy. Patients on either NSAID or COX-2 therapy had an increased p53 and decreased EGFR expression. PPI therapy reversed not only the increased cell proliferation and p53 expression, but also the suppressed EGFR expression when administered as co-therapy. The fewer gastrointestinal side effects observed during chronic COX-2 therapy may partially be the result of the higher cell proliferation. This effect is not mediated by the EGFR pathway. PPI co-therapy normalizes the disturbed cell kinetics irrespective of NSAID treatment used.

QSAR and classification models of a novel series of COX-2 selective inhibitors: 1,5-diarylimidazoles based on support vector machines

The support vector machine, which is a novel algorithm from the machine learning community, was used to develop quantitation and classification models which can be used as a potential screening mechanism for a novel series of COX-2 selective inhibitors. Each compound was represented by calculated structural descriptors that encode constitutional, topological, geometrical, electrostatic, and quantum-chemical features. The heuristic method was then used to search the descriptor space and select the descriptors responsible for activity. Quantitative modelling results in a nonlinear, seven-descriptor model based on SVMs with root mean-square errors of 0.107 and 0.136 for training and prediction sets, respectively. The best classification results are found using SVMs: the accuracy for training and test sets is 91.2% and 88.2%, respectively. This paper proposes a new and effective method for drug design and screening.

Colorectal cancer chemoprevention--an overview of the science

The development and dissemination of sophisticated detection technologies have recently exposed the high prevalence of preinvasive colorectal neoplasia in the adult U.S. population. Although cancer screening and surveillance provide opportunities for risk stratification, they achieve risk reduction only when coupled with effective interventions. This review surveys the lead compounds for colorectal cancer prevention and the measures by which they may be prioritized for clinical testing. Clinical trials remain the rate-limiting step in agent development, and novel trial designs are needed to hasten agent identification and testing for cancer prevention. Innovative research models include the nesting of prevention end points within cancer treatment trials and within trials testing promising preventive compounds intended for nononcologic indications.

Gastrointestinal side effects of drugs

Drugs can have adverse effects on any part of the gastrointestinal (GI) tract from mouth to colon. It is essential that a detailed and accurate drug history is taken in patients presenting with GI complaints. Many drug-induced effects will regress or heal on cessation of treatment. NSAIDs are usually associated with gastric and duodenal ulcers but are also recognised to cause lichen planus in the mouth, oesophageal inflammation and strictures, and small bowel and colonic ulcers and strictures. A newer class of anti-inflammatory drugs, the cyclooxygenase-2 (COX-2)-selective inhibitors, have been developed and have a more favourable GI safety profile than standard NSAIDs. Acute diarrhoea, relapse of inflammatory bowel disease (IBD), microscopic colitis and acute pancreatitis are also induced by ingestion of standard NSAIDs. The calcium antagonists, phenytoin and cyclosporin, induce gum hyperplasia, particularly in patients with poor oral hygiene. Alendronate, a bisphosphonate, has been associated with development of oesophageal ulcers, and specific recommendations are now given to reduce this complication. Of the many different forms of colitis associated with drug ingestion, the most frequent is pseudomembranous colitis. This is a complication of antibiotics and is caused by the toxin produced by Clostridium difficile. Many drugs have been associated with the development of acute pancreatitis, although a definite cause and effect relationship has been shown for only a few drugs. These include didanosine, furosomide, corticosteroids, azathioprine and sodium valproate.

Investigations of new lead structures for the design of novel cyclooxygenase-2 inhibitors

On the basis of molecular modelling studies, five new compounds were synthesised and studied in an attempt to design new lead structures as selective COX-2 inhibitors.

Anti-inflammatory drugs, cyclooxygenases and other factors

Non-steroidal anti-inflammatory drugs (NSAIDs), which for so many years have played major roles in treating inflammation, pain and fever, have had major recent boosts to various therapeutic aspects. These include the impetus generated by the cyclooxygenase (COX)-2 inhibitors celecoxib and rofecoxib, a greater understanding of NSAID non-prostaglandin modes of action and the use of NSAIDs in cancer and Alzheimer's disease. Many of these aspects are covered in articles in this issue of Expert Opinion on Pharmacotherapy.