Exogenous Ghrelin Accelerates the Healing of Acetic Acid-Induced Colitis in Rats

Previous studies have shown that ghrelin reduces colonic inflammation induced by trinitrobenzene sulfonic acid and dextran sodium sulfate. In the present study we determined the effect of treatment with ghrelin on the course of acetic acid-induced colitis in rats. Rectal administration of 3% acetic acid solution led to induction of colitis in all animals. Damage of the colonic wall was accompanied by an increase in mucosal concentration of pro-inflammatory interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), as well mucosal activity of myeloperoxidase. Moreover, induction of colitis led to a reduction in colonic blood flow and DNA synthesis. Administration of ghrelin after induction of colitis led to faster regeneration of the colonic wall and reduction in colonic levels of IL-1β, TNF-α, and myeloperoxidase. In addition, treatment with ghrelin improved mucosal DNA synthesis and blood flow. Our study disclosed that ghrelin exhibits a strong anti-inflammatory and healing effect in acetic acid-induced colitis. Our current observation in association with previous findings that ghrelin exhibits curative effect in trinitrobenzene sulfonic acid- and dextran sodium sulfate-induced colitis suggest that therapeutic effect of ghrelin in the colon is universal and independent of the primary cause of colitis.

Tachykinins potently stimulate human small bowel blood flow: a laser Doppler flowmetry study in humans

BACKGROUND

The two tachykinins substance P and neurokinin A are abundantly present in the gastrointestinal tract. Substance P preferring neurokinin 1 receptors are mainly found in submucosal blood vessels while neurokinin A preferring neurokinin 2 receptors seem to be confined to smooth muscle cells. Tachykinin effects on intestinal mucosal blood flow in humans are not known.

AIM

To study the effects of substance P and neurokinin A on small bowel mucosal blood flow in humans.

METHODS

A manometry tube supplied with single fibre microprobes recorded mucosal blood flow in the proximal small bowel using laser Doppler flowmetry, concomitant with luminal manometry, defining phases I, II, and III of the migrating motor complex. Simultaneously, flowmetry of temporal skin was performed. Under fasting conditions saline was infused intravenously over four hours followed by infusion of substance P, neurokinin A, or saline.

RESULTS

During phase I, substance 1-6 pmol/kg/min increased mucosal blood flow dose dependently by a maximum of 158%. Blood flow of the temporal skin increased in parallel. Neurokinin A 6-50 pmol/kg/min increased mucosal blood flow maximally by 86% at 25 pmol/kg/min while blood flow of temporal skin increased at all doses. Substance P at all doses and neurokinin A at the highest dose only, increased pulse rate. Systolic blood pressure was unchanged by either peptide while substance P at the highest dose decreased diastolic pressure.

CONCLUSION

Tachykinins increase blood flow of the small bowel and temporal skin. With substance P being more potent than neurokinin A, these effects are probably mediated through neurokinin 1 receptors.

Gastrointestinal tolerability of meloxicam and piroxicam: a double-blind placebo-controlled study

AIMS

The aim of the study was to compare the effects of meloxicam and piroxicam on the gastroduodenal mucosa in healthy adults.

METHODS

Forty-four healthy volunteers were given a 28 day course of either meloxicam 15 mg, piroxicam 20 mg or placebo. Damage to the oesophageal, gastric and duodenal mucosa was assessed, mucosal blood flow (MBF) measured at endoscopy and biopsies taken for prostaglandin content and microscopic assessment of damage before NSAID administration and during days 1, 7 and 28 of continued intake.

RESULTS

Maximal macroscopic gastric mucosal damage (median grade+IQR) occurred within 24 h of piroxicam administration, the damage score increasing from 0 to 2.5 (0-3) (P=0.02) at day 1 before falling to 2.0 (0-2) at day 7 and 0 (0-1) at day 28 with resolution of damage observed in six out of the seven subjects who sustained acute injury. No significant macroscopic gastric damage occurred in either of the two other groups although some minor damage was observed in seven subjects taking placebo and five taking meloxicam. There was a trend towards piroxicam causing more acute gastric damage than meloxicam (P=0.06). Baseline antral, body and duodenal MBF were similar in all three groups. No significant changes occurred in any of the groups on any of the visits. There were also no changes in gastric mucosal prostaglandin content in any group.

CONCLUSIONS

These observations suggest that meloxicam causes little acute damage to the upper gastrointestinal tract and piroxicam causes some acute gastric injury but such damage resolves in most subjects by 28 days.

Nutritional support to prevent and treat multiple organ failure

Enteral nutrition (EN) has several advantages over parenteral nutrition (PN) for postoperative/posttrauma patients. Modern technologies for tube-feeding have made early EN possible. Jejunal tube-feeding has advantages over gastric tube-feeding: faster metabolic recovery, less vomiting, and less risk of regurgitation and aspiration. Immediate or early EN stimulates the splanchnic and hepatic circulations, improves mucosal blood flow, prevents intramucosal acidosis and permeability disturbances, and eliminates the need for stress ulcer prophylaxis. Saliva containing important antimicrobial substances and gastric acidity are important in sepsis prevention. Chewing, saliva, and gastric acidity support gastric nitric oxide (NO) release, important for mucosal blood flow, gastrointestinal (GI) motility, mucus formation, and bacteriostasis. An oral supply of NO-donating substances and chewing of nitrate-rich food, such as lettuce or spinach, can be useful. Oral and mucosa-protective lipids are recommended. H2 blockers and saliva-inhibiting drugs are avoided. Immediate EN should be given, starting with 25 ml/hr and increasing to 100 ml/hr over 24 to 48 hours. For the immunocompromised patient special attention should be given to the purity of water. Bottled water can contain bacteria such as Pseudomonas. Food antioxidants such as glutathione, vitamin E, and beta-carotenes are important. Ingredients for the colonic mucosa are important. Approximately 10% of caloric need is satisfied by so-called colonic food (prebiotics), fermented at the level of the colonic mucosa to produce colonic mucosa nutrients and to prevent gut origin sepsis. More than 10 g of fiber per day is recommended. The fermenting flora (probiotic flora) is deranged owing to disease or antibiotic treatment, and resupply of flora is important. A new concept of ecoimmune nutrition is presented for enteral supply of mucosa-reconditioning ingredients: new surfactants, pseudomucus, fiber, amino acids such as arginine, and mucosa-adhering Lactobacillus plantarum 299.