Effect of peroxisome proliferator-activated receptor-alpha agonist (bezafibrate) on gastric secretion and gastric cytoprotection in rats

A comprehensive review on phytochemicals as potential therapeutic agents for stress-induced gastric ulcer

Gastric ulcers are the most common chronic gastrointestinal tract disorders, marked by an inflamed break of the mucus membrane covering the alimentary tract. According to recent research, stress-induced ulcers are widespread in our society. A stress ulcer is a mucosal defect that may become complicated due to upper gastrointestinal tract bleeding. The underlying cause of this condition is pH. Physiological stress leads to severe sickness by triggering the excessive secretion of peptic juices or gastric acid. There is a never-ending quest for safe and affordable medication for this disorder. Nature offers many medicinal plants that can be used to treat a wide range of human ailments. Due to their relatively harmless and comparatively free of harmful effects, health-promoting features, pharmacological practices, and affordability to common people to regulate various diseases, medicinal plants, and herbal preparations are gaining a lot of interest in scientific communities these days. Many studies have recently been performed to classify extracts and their constituents that may have a therapeutic effect on peptic ulcers. Therefore, this review aims to address the molecular mechanisms and pharmacological effects of various phytochemicals related to stress-induced gastric ulcers. Combining phytochemical constituents with modern drugs and treatment methods can lead to the development of therapeutic drugs for gastric ulcers. Gastric ulcers and other related diseases may be treated permanently with this approach.

Antihyperlipidemic drugs mitigate the elevated incidence of peptic ulcer disease caused by hyperlipidemia: A cohort study

BACKGROUND

Several risk factors for peptic ulcer disease (PUD) have been identified; however, the recurrence rate of PUD remains high even with standard ulcer treatments. High cholesterol levels have been proposed as a risk factor for PUD, but clinical evidence remains limited. Therefore, this database study investigated whether hyperlipidemia increases PUD risk and whether antihyperlipidemic drugs reduce this risk.

METHODS

A long-term cohort design was adopted, and Taiwan's National Health Insurance Research Database was used to enroll patients diagnosed with hyperlipidemia between 2000 and 2016. Patients without hyperlipidemia were randomly matched based on variables such as age and gender to establish a comparison cohort at a 1:1 ratio. Another cohort study was conducted to determine whether antihyperlipidemic drugs or red yeast rice prescriptions can reduce the incidence of PUD in patients with hyperlipidemia.

RESULTS

The overall incidence of PUD was 1.48 times higher in the hyperlipidemia cohort (203,235 patients) than in the nonhyperlipidemia cohort (adjusted hazard ratio, 1.48; 95% CI, 1.46-1.50; p < 0.001). Among the patients with hyperlipidemia, those who used antihyperlipidemic drugs with or without red yeast rice prescriptions exhibited a lower risk of developing PUD relative to those who did not use them; the adjusted hazard ratios were 0.33 (95% CI, 0.21-0.52) and 0.81 (95% CI, 0.78-0.84), respectively. When the cumulative exposure to antihyperlipidemic drugs and red yeast rice prescriptions increased, the risk of developing PUD showed a decreasing trend, which was statistically significant for antihyperlipidemic drugs but not for red yeast rice.

CONCLUSION

Hyperlipidemia is associated with a higher risk of PUD, which can be reduced through the administration of antihyperlipidemic drugs with or without red yeast rice prescriptions.

Role of peroxisome proliferator-activated receptors alpha and gamma in gastric ulcer: An overview of experimental evidences

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors belonging to the nuclear hormone receptor superfamily. Three subtypes, PPARα, PPARβ/δ, and PPARγ, have been identified so far. PPARα is expressed in the liver, kidney, small intestine, heart, and muscle, where it activates the fatty acid catabolism and control lipoprotein assembly in response to long-chain unsaturated fatty acids, eicosanoids, and hypolipidemic drugs (e.g., fenofibrate). PPARβ/δ is more broadly expressed and is implicated in fatty acid oxidation, keratinocyte differentiation, wound healing, and macrophage response to very low density lipoprotein metabolism. This isoform has been implicated in transcriptional-repression functions and has been shown to repress the activity of PPARα or PPARγ target genes. PPARγ1 and γ2 are generated from a single-gene peroxisome proliferator-activated receptors gamma by differential promoter usage and alternative splicing. PPARγ1 is expressed in colon, immune system (e.g., monocytes and macrophages), and other tissues where it participates in the modulation of inflammation, cell proliferation, and differentiation. PPARs regulate gene expression through distinct mechanisms: Ligand-dependent transactivation, ligand-independent repression, and ligand-dependent transrepression. Studies in animals have demonstrated the gastric antisecretory activity of PPARα agonists like ciprofibrate, bezafibrate and clofibrate. Study by Pathak et al also demonstrated the effect of PPARα agonist, bezafibrate, on gastric secretion and gastric cytoprotection in various gastric ulcer models in rats. The majority of the experimental studies is on pioglitazone and rosiglitazone, which are PPARγ activators. In all the studies, both the PPARγ activators showed protection against the gastric ulcer and also accelerate the ulcer healing in gastric ulcer model in rats. Therefore, PPARα and PPARγ may be a target for gastric ulcer therapy. Finally, more studies are also needed to confirm the involvement of PPARs α and γ in gastric ulcer.

PPARs: history and advances

Peroxisome proliferator-activated receptors (PPARs) are members of the steroid hormone receptor superfamily, discovered in 1990. To date, three PPAR subtypes have been identified; PPARα, PPAR β/δ, and PPARγ. These receptors share a high degree of homology but differ in tissue distribution and ligand specificity. PPARs have been implicated in the etiology as well as treatment of several important diseases and pathological conditions such as diabetes, inflammation, senescence-related diseases, regulation of fertility, and various types of cancer. Consequently, significant efforts to discover novel PPAR roles and delineate molecular mechanisms involved in their activation and repression as well as develop safer and more effective PPAR modulators, as therapeutic agents to treat a myriad of diseases and conditions, are underway. This volume of Methods in Molecular Biology contains details of experimental protocols used in researching these receptors.

Evaluation of the antipeptic ulcer activity of the leaf extract of Plantago lanceolata L. in rodents

The effect of the leaf extract of Plantago lanceolata L. (Plantaginaceae) on gastric secretion and cytoprotection was evaluated using different models of gastroduodenal ulcer, including acetic acid induced chronic gastric ulcer, indomethacin induced gastric ulcer, cysteamine induced duodenal ulcer and pylorus ligation induced gastric ulcer. The aqueous extract was administered at 200 mg/kg and 400 mg/kg and 140 mg/kg and 280 mg/kg for mice and rats, respectively, and compared with vehicle or the standard, ranitidine (50 or 70 mg/kg) or misopristol (280 μg/kg). In addition, activity of the mucilage (172 mg/kg) was also evaluated in acetic acid induced chronic gastric ulcer. Administration was done orally except in pylorus ligation, where the intraduodenal route was used. In all cases, higher doses of the extract provided better protection than lower doses and the mucilage, hinting at a dose-dependent effect. Whilst higher doses of the extract showed a better healing of the ulcer as well as protection in indomethacin and pylorus ligation models, activities of lesser magnitude than ranitidine were noted in the cysteamine model. Together these findings indicate that higher doses used in the present study provided an overall better protection against gastroduodenal ulcers than the standard drugs employed through antisecretory and cytoprotective mechanisms.