Ghrelin and glucagon-like peptide-2 increase immediately following massive small bowel resection

Ghrelin Levels in Children With Intestinal Failure Receiving Long-Term Parenteral Nutrition

Background

Children with intestinal failure (IF) require parenteral nutrition (PN). Transition to oral and enteral nutrition (EN) can be difficult also due to abnormal gastrointestinal motility. The gut hormone ghrelin is increased in states of negative energy balance, functioning to preserve euglycemia, and also has appetite stimulating and prokinetic properties. We aimed to evaluate and compare ghrelin levels in children with IF, and to assess the relationship with PN-dependency.

Methods

In this exploratory prospective multicenter study, plasma acylated (AG) and unacylated (UAG) ghrelin levels were measured in children with short bowel syndrome (SBS) and with functional IF (pseudo-obstruction or any enteropathy) and compared with healthy control subjects. Spearman’s rho (r_s) was used to assess correlations of AG and UAG with PN-dependency (%PN) and parenteral glucose intake.

Results

Sixty-four samples from 36 IF-patients were analyzed. Median baseline AG and UAG levels were respectively 279.2 and 101.0 pg/mL in children with SBS (n = 16), 126.4 and 84.5 pg/mL in children with functional IF (n = 20) and 82.4 and 157.3 pg/mL in healthy children (n = 39). AG levels were higher in children with SBS and functional IF than in healthy children (p = 0.002 and p = 0.023, respectively). In SBS, AG positively correlated with %PN (r_s = 0.5, p = 0.005) and parenteral glucose intake (r_s = 0.6, p = 0.003). These correlations were not observed in functional IF.

Conclusion

Children with IF had raised AG levels which could be related to starvation of the gut. The positive correlation between AG and glucose infusion rate in SBS suggests an altered glucoregulatory function.

Expression of TLR2 and TLR5 in distal ileum of mice with obstructive jaundice and their role in intestinal mucosal injury

INTRODUCTION

The aim was to investigate the expression of TLR2 and TLR5 in the distal ileum of mice with obstructive jaundice (OJ) and their role in intestinal mucosal injury.

MATERIAL AND METHODS

A total of 100 male C57BL/6J mice were randomly assigned to two groups: (I) sham operation (SH); (II) bile duct ligation (BDL). The mice were respectively sacrificed before operation and on the 1st, 3rd, 5th and 7th days after operation to collect specimens. Various indicators were detected by PCR, immunohistochemistry and other methods.

RESULTS

TLR2 was increased gradually with the extension of OJ time in the BDL group (p < 0.05). However, the changes in the expression of TLR5 were not obvious at different time points. The amount of Bifidobacteria and Lactobacillus showed downward trends in intestinal tract of the BDL group. Furthermore, the amount of Escherichia coli was increased in intestinal tract of the BDL group. The pathological score of intestinal mucosa and the expression of NF-κB increased gradually in the BDL group with the extension of OJ time. There were positive correlations between the pathological score of intestinal mucosa and expressions of TLR2(r = 0.767, p < 0.05) and NF-κB (r = 0.817, p < 0.05) in BDL group. NF-κB expression was positively correlated with TLR2 expression(r = 0.706, p < 0.05).

CONCLUSIONS

Disturbance of intestinal flora caused by OJ could increase the expression of NF-κB via up-regulating the expression of TLR2 to activate the downstream signaling pathway, thus aggravated the injury of intestinal mucosa.

Ghrelin stimulates intestinal adaptation following massive small bowel resection in parenterally fed rats

BACKGROUND

Since short bowel syndrome (SBS) patients face life-threatening conditions, the development of therapeutic strategies to induce intestinal adaptation has been investigated. Ghrelin, a ligand of growth hormone (GH) secretagogue-receptor that stimulates the release of GH and insulin like growth factor-1 (IGF-1), has several pleiotropic effects. We investigated whether ghrelin induces intestinal adaptation in parenterally fed rats with SBS.

METHODS

Sprague-Dawley rats underwent venous catheterization and were divided into 3 groups: those receiving 90% small bowel resection while leaving the proximal jejunum and distal ileum (90% SBR) with TPN (SBS/TPN group), those receiving 90% SBR with TPN + ghrelin (SBS/TPN/ghrelin group), and those receiving sham operation and fed chow (sham group). Ghrelin was administered intravenously at 10 μg/kg/day. On Day 13, the rats were euthanized and the small intestine harvested, and the histology and crypt cell proliferation rates (CCPR), apoptosis, and nutrient transporter protein levels were analyzed and the plasma hormones were measured.

RESULTS

The villus height and crypt depth of the ileum in the SBS/TPN/ghrelin group were significantly higher than in the SBS/TPN group. The CCPR of the jejunum and the ileum significantly increased by the administration of ghrelin; however, the apoptosis rates did not significantly differ between the SBS/TPN and SBS/TPN/ghrelin groups. Significant differences did not exist in the plasma IGF-1 and nutrient transporter protein levels among three groups.

CONCLUSIONS

The intravenous administration of ghrelin stimulated the morphological intestinal adaptation of the ileum to a greater degree than the jejunum due to the direct effect of ghrelin.

Effect of proximal versus distal 50% enterectomy on nutritional parameters in rats preconditioned with a high-fat diet or regular chow

Obesity may protect against the nutritional consequences of short bowel syndrome. We hypothesized that rats preconditioned with an obesogenic diet would have better outcomes after surgical induction of short bowel syndrome compared to rats on regular chow. Rats were fed a high-fat diet or regular rat chow for six months, and then underwent 50% proximal, 50% distal, or sham enterectomy. Food intake, weight, and body composition were monitored before and for 4 weeks after surgery. The high-fat diet consistently produced obesity (>25% body fat). All procedures induced weight loss, but there was no discernable difference between resection vs. sham resection. Rats on the high-fat diet had a greater post-resection loss of body fat compared to rats on chow (36 vs. 26 g, respectively). There was a nonsignificant trend of less lean mass loss in the former compared to the latter rats (16 vs. 33 g, respectively). Enterectomy moderated serum ghrelin, GIP, PPY, insulin, and leptin. Intestinal adaptation was not different between obese vs. non-obese rats. Rats preconditioned with the high-fat diet may have had better retention of lean body mass after a surgical procedure compared to rats on chow. The effect of 50% enterectomy was less than expected.

Citrulline levels following proximal versus distal small bowel resection

PURPOSE

Citrulline, a nonprotein amino acid synthesized by enterocytes, is a biomarker of bowel length and the capacity to wean from parenteral nutrition. However, the potentially variant effect of jejunal versus ileal excision on plasma citrulline concentration [CIT] has not been studied. This investigation compared serial serum [CIT] and mucosal adaptive potential after proximal versus distal small bowel resection.

METHODS

Enterally fed Sprague-Dawley rats underwent sham operation or 50% small bowel resection, either proximal (PR) or distal (DR). [CIT] was measured at operation and weekly for 8 weeks. At necropsy, histologic features reflecting bowel adaptation were evaluated.

RESULTS

By weeks 6-7, [CIT] in both resection groups significantly decreased from baseline (P<0.05) and was significantly lower than the concentration in sham animals (P<0.05). There was no difference in [CIT] between PR and DR at any point. Villus height and crypt density were higher in the PR than in the DR group (P≤0.02).

CONCLUSION

[CIT] effectively differentiates animals undergoing major bowel resection from those with preserved intestinal length. The region of intestinal resection was not a determinant of [CIT]. The remaining bowel in the PR group demonstrated greater adaptive potential histologically. [CIT] is a robust biomarker for intestinal length, irrespective of location of small intestine lost.