Endothelial changes precede mucosal ulceration induced by indomethacin: an experimental study in the rat

Emu oil offers protection in Crohn's disease model in rats

Background

Emu oil is a product of animal origin used for the treatment of inflammation, burns etc. as a part of aboriginal medicine in Australia. Crohn’s disease is a common inflammatory manifestation in humans and other animal species relating to the ulceration and digestive disturbances in upper gastro-intestinal tract. Aloe vera is commonly used substance from plant sources for inflammation, wound healing and various other properties. Given the difference in the source of the substances all the while playing a similar therapeutic role in different parts of the world, the present investigation was undertaken to evaluate the protective effect of aloe vera and emu oil alone and in combination; in comparison to sulfasalazine (Allopathic drug) as an alternative for the treatment of Crohn’s disease.

Methods

Wistar albino rats were divided into six groups with two sub-groups of six animals each. After pre-treating the animals with sulfasalazine, aloe vera, emu oil and their combination for five consecutive days, the animals were sub-cutaneously administered indomethacin on 4^th and 5^th day and each sub-group was sacrificed on day 6 and 9. After sacrifice, serum and intestine of these animals was collected. Intestine length from duodenum till caecum was measured for estimating relative organ weight and disease activity index. Part of intestine was preserved in formalin for histopathology while the rest was used for analysis of oxidative parameters and myeloperoxidase. Serum collected was used for measuring alkaline phosphatase and cholesterol.

Results

Assessment of the parameters in treatment groups indicated that the combination of aloe vera and emu oil resulted in better protection by suppressing the oxidative (P < 0.05) and histomorphological changes indicating a enhanced effect of these two agents which was found to be better than sulfasalazine.

Conclusion

The combination of emu oil and aloe vera exhibited enhanced effect resulting in significant protection from indomethacin induced ulceration. This might be due to the different mechanism of anti-inflammatory effects (Salicylic acid in aloe vera and n3, n6 fatty acids acting as pseudosubstrates to cyclooxygenase enzyme) of components of the animal and plant products tested.

Chemoprevention of colorectal cancer: feasibility in everyday practice?

Chemoprevention means the use of agents to prevent, delay, or reverse carcinogenesis. This review was designed to critically discuss the most promising agents in colorectal cancer (CRC) chemoprevention. Aspirin is the best studied chemopreventive agent for CRC. Optimal chemoprevention requires long-term use and high dose of aspirin that may increase the risk of gastrointestinal bleeding. Nonsteroidal anti-inflammatory drugs and selective cyclooxygenase-2 inhibitors may also be candidates for chemoprevention. The regular use of nonsteroidal anti-inflammatory drugs, however, causes adverse effects including gastrointestinal bleeding, and cyclooxygenase-2 inhibitors may increase the risk of cardiovascular events. In patients with ulcerative colitis 5-aminosalicylates reduce the risk of CRC and dysplasia. Ursodeoxycholic acid can reduce the risk of dysplasia or CRC in patients with primary sclerosing cholangitis and ulcerative colitis. Current data are insufficient to support the use of hormone replacement therapy to reduce the risk of CRC. Statins may have chemopreventive effects, but further investigation of their overall benefits in preventing CRC is warranted. Antioxidant supplements cannot prevent CRC. The usefulness of selenium, folate, calcium, and vitamin D awaits further evaluation. Chemoprevention cannot yet be accepted as standard medical practice. Use of chemopreventive agents cannot be a substitute for colorectal surveillance.

Mechanisms underlying intestinal injury induced by anti-inflammatory COX inhibitors

By far the most attention has been paid to the deleterious actions of nonsteroidal anti-inflammatory drugs (NSAIDs), including isoform selective agents that inhibit cyclooxygenase (COX), on the upper gastrointestinal tract, particularly the gastric and duodenal mucosa. However, recent studies confirm a relatively high incidence of serious clinical events, especially with the more-established drugs of this class, involving the small intestine. Pathogenic factors that have been proposed from early studies in such enteropathy have included the enterohepatic circulation of the nonsteroidal anti-inflammatory drugs, inhibition of cyclooxygenase, surface epithelial changes and focal microvascular events. More recent work has concerned the role of infiltrating inflammatory cells, the relative roles of cyclooxygenase isoforms, COX-1 and COX-2 and the key involvement of inducible nitric oxide (NO) synthase and its product in combination with superoxide, peroxynitrite. In the present review, evidence for the underlying involvement of each these processes, and their sequential integration in the development of the intestinal injury and ulceration promoted by nonsteroidal anti-inflammatory drugs has been considered.

Inhibition of angiogenesis by NSAIDs: molecular mechanisms and clinical implications

Angiogenesis, the formation of new capillary blood vessels, is a fundamental process essential for reproduction and embryonic development. It is crucial to the healing of tissue injury because it provides essential oxygen and nutrients to the healing site. Angiogenesis is also required for cancer growth and progression since tumor growth requires an increased nutrient and oxygen supply. Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most widely used drugs worldwide for treating pain, arthritis, cardiovascular diseases, and more recently for colon cancer prevention. However, NSAIDs produce gastrointestinal ulcers and delay ulcer healing. Recently NSAIDs have been demonstrated to inhibit angiogenesis, but the underlying mechanisms are only beginning to be elucidated. The inhibition of angiogenesis by NSAIDs is a causal factor in the delay of ulcer healing, and it is becoming clear that this is also likely to be one of the mechanisms by which NSAIDs can reduce or prevent cancer growth. Based on the experimental data and the literature, the mechanisms by which NSAIDs inhibit angiogenesis appear to be multifactorial and likely include local changes in angiogenic growth factor expression, alteration in key regulators and mediators of vascular endothelial growth factor (VEGF), increased endothelial cell apoptosis, inhibition of endothelial cell migration, recruitment of inflammatory cells and platelets, and/or thromboxane A2 mediated effects. Some of these mechanisms include: inhibition of mitogen-activated protein (Erk2) kinase activity; suppression of cell cycle proteins; inhibition of early growth response (Egr-1) gene activation; interference with hypoxia inducible factor 1 and VEGF gene activation; increased production of the angiogenesis inhibitor, endostatin; inhibition of endothelial cell proliferation, migration, and spreading; and induction of endothelial apoptosis.