Nutritional monitoring of a pediatric burn patient

Ghrelin abates bacterial translocation following burn injury by improving gastric emptying

BACKGROUND

In severe burns, increased intestinal permeability facilitates bacterial translocation, resulting in systemic endotoxemia and multi^- organ failure. We investigated the role of burn-induced gastrointestinal dysmotility (BIGD) in promoting bacterial translocation following burn injury, and the protective effect of ghrelin in this process.

METHODS

We assessed gastric emptying (GE%) and intestinal transit (IT by geometric center "GC") in a 60% total body surface area scald burn rat model and measured bacterial counts in mesenteric lymph nodes (MLN) and distal small intestine by colony-forming unit per gram of tissue (CFU/g). A group of animals was treated with ghrelin or saline after burn.

KEY RESULTS

Scald burn was associated with a significant delay in GE (62% ± 4% vs 74% ± 4%; P = .02) and a trend of delay in intestinal transit (GC: 5.5 ± 0.1 vs 5.8 ± 0.2; P = .09). Concurrently, there was a marginal increase in small intestinal bacterial overgrowth (6 × 10⁵ vs 2 × 10⁵  CFU/g; P = .05) and significant translocation to MLN (2 × 10² vs 4 × 10¹ ; P = .03). We observed a negative correlation between GE and intestinal bacterial overgrowth (r_s  = -0.61; P = .002) and between IT and translocation (r_s  = -0.63; P = .004). Ghrelin administration significantly accelerated GE following burn injury (91% ± 3% vs 62% ± 4; P = .03), reduced small intestinal bacterial overgrowth, and completely inhibited translocation to MLN (0.0 vs 5 × 10² ; P = .01).

CONCLUSIONS & INFERENCES

Burn-induced gastrointestinal dysmotility is correlated with the systemic translocation of gram-negative gut bacteria that are implicated in multiple organ failure in burn patients. Therapeutic interventions to restore BIGD are warranted (Neurogastroenterol Motil, 2012, 24, 78).

Mechanisms of burn-induced impairment in gastric slow waves and emptying in rats

Delayed gastric emptying is common following severe large cutaneous burns; however, the mechanisms of burn-induced delayed gastric emptying remain unknown. The aim of this study was to explore the possible involvement of hyperglycemia and cyclooxygenase-2 receptors in the burn-induced gastric dysrhythmias. Gastric slow waves and gastric emptying were assessed in rats 6 h following sham or burn injury. Animals were randomized to one sham-burn and seven burn groups: untreated; two groups of saline treated (control); insulin treated (5 IU/kg); cyclooxygenase-2 inhibitor treated (10 mg/kg); ghrelin treated (2 nmol/rat); and gastric electrical stimulation treated. It was found that 1) severe burn injury impaired gastric slow waves postprandially and delayed gastric emptying; 2) the impairment in gastric slow waves included a decrease in the slow-wave frequency and in the percentage of normal slow waves, and an increase in the percentage of bradygastria (P = 0.001, 0.01, and 0.01, respectively vs. preburn values). None of the gastric slow-wave parameters was significantly correlated with gastric emptying; 3) cyclooxygenase-2 inhibitor normalized burn-induced delayed gastric emptying (P = 0.3 vs. sham-burn), but not gastric dysrhythmias (P < 0.002 vs. sham), whereas insulin normalized both gastric emptying (P = 0.4 vs. sham-burn) and gastric dysrhythmias (P = 0.3 vs. sham-burn); 4) both gastric electrical stimulation and ghrelin accelerated burn-induced delayed gastric emptying (P = 0.002 and 0.04, respectively, vs. untreated burn). In conclusion, hyperglycemia alters gastric slow-wave activity and delayed gastric emptying, while cyclooxygenase-2 inhibition delays gastric emptying without altering gastric slow-wave activity.