Age-related changes in duodenal adaptation after distal small bowel resection in rat

Long-Term Outcomes in Patients with Intestinal Failure Due to Short Bowel Syndrome and Intestinal Fistula

Short bowel syndrome (SBS) and enterocutaneous or enteroatmospheric fistulas are common indications for home parenteral nutrition (HPN). However, there are few data describing factors influencing surgical decision-making or outcomes particularly following fistula development. We aimed to compare outcomes between patients with SBS and fistulas and explore surgical decision-making. HPN-dependent adults from 2001−2018 at a national reference centre were included in this study. HPN cessation was analysed using death as competing risk. In total, 465 patients (SBS (62%), fistula (38%)) were included, with median HPN dependency of 2.6 years. In total, 203 patients underwent reconstructive surgery; while frailty was the commonest reason for not undergoing surgery (49.2%), 22.7% declined surgery. Overall, 170 ceased HPN, with a probability of 13.8%, 34.1% and 38.3% at 1, 5 and 10 years, respectively. Patients undergoing surgery had higher nutritional autonomy rates (109.8 incidences/1000 patient years) compared to those not undergoing surgery (18.1 incidences/1000 patient years; p < 0.001). A total of 295 patients (63.4%) were predicted to cease HPN based on gastrointestinal anatomy but only 162/295 (54.9%) achieved this; those unable to do so were older with a higher comorbidity index. There were no differences in long-term nutritional and survival outcomes or surgical decisions between patients with SBS and fistulas, or between enterocutaneous and enteroatmospheric fistulas. This study represents one of the largest datasets describing the ability of HPN-dependent patients with SBS or fistulas to achieve nutritional autonomy. While reconstructive surgery facilitates HPN cessation, approximately one-fifth of patients declined surgery despite HPN dependency. These data will better inform patient expectation and help plan alternative therapies.

Nutrient absorption and intestinal adaptation with ageing

Malabsorption of carbohydrates, lipids, amino acids, minerals and vitamins has been described in the elderly. The ability of the intestine to adapt may be impaired in the elderly and this may lead to further malnutrition. Dietary manipulation may prove to be useful to enhance the needed intestinal absorption with ageing. There is an age-associated increase in the prevalence of dyslipidaemia as well as diabetes. These conditions may benefit from nutritional intervention targeted at reducing the absorption of some nutrients. With the continued characterization of the proteins involved in sterol and fatty acid absorption, therapeutic interventions to modify absorption may become available in the future.

Growth hormone plus high protein diet promotes adaptation after massive bowel resection in aged rats

OBJECTIVE

To determine whether GH improves adaptation following massive bowel resection in the aged rat fed on a high protein-content diet.

MATERIAL AND METHODS

Seventy-seven male Wistar rats aged 22+/-1 months underwent 80% bowel resection or laparotomy (sham-operation). They were randomly placed into one of eight groups, treated with either growth hormone (1mg/kg/day) or saline, and fed a liquid diet containing either a high or a normal protein content. Intestinal tissue and blood samples were taken seven days after surgery and analysed to measure intestinal mucosal proliferation and mucosal height, as well as plasma levels of IGF-1 and somatostatin.

RESULTS

Resection of the small bowel in aged rats remarkably increased villous height and crypt proliferation. Growth hormone did not potentiate the increase in mucosal height and crypt proliferation observed after intestinal resection in aged rats fed a normal protein content diet, but did in those receiving a high-protein diet. Plasma levels of IGF-1 and somatostatin were not modified by surgery or treatment.

CONCLUSION

Growth hormone may increase the adaptation of intestinal mucosa in aged rats undergoing massive intestinal resection, but requires an adequate nutritional support with increased amounts of high quality protein.

Stimulation of pancreatic growth. Distal small bowel resection mediated by increased levels of cholecystokinin

SUMMARY BACKGROUND DATA

Distal, but not proximal, resection of the small bowel induces growth of rat pancreas, but the mechanism of this phenomenon is poorly clarified. The release of cholecystokinin (CCK), a trophic hormone for the pancreas, is regulated by a negative-feedback control of bile salts. The ileum is a major site for reabsorption of bile salts. Thus, unsuppressed release of CCK due to deleted reabsorption of bile salts after distal small bowel resection may be a cause of pancreatic growth. In this study, the authors have examined whether pancreatic growth after distal small bowel resection was mediated by endogenous CCK and have determined whether the mechanism of this pancreatic growth required biosynthesis of polyamine.

METHODS

Male Fischer 344 rats underwent 70% distal small bowel resection or transection of the ileum. Beginning 48 hours after surgery, CR1409 (a CCK-receptor antagonist) or saline was injected subcutaneously every 8 hours. All animals were pair-fed and killed 14 days after surgery. The pancreas from each rat was excised, weighed, and assayed for DNA, RNA, protein, and polyamine content.

RESULTS

Distal small bowel resection increased pancreatic weight, DNA, RNA, and protein, as well as polyamine levels; all of these increases were significantly suppressed by CR1409. Postprandial release of CCK into the circulation was significantly increased after distal small bowel resection.

CONCLUSIONS

Pancreatic growth after distal small bowel resection was associated with the stimulation of polyamine biosynthesis; growth appeared to be mediated by endogenous CCK.

Altered polyamine biosynthesis with aging after massive proximal small bowel resection in rat

We examined the effect of aging on polyamine biosynthesis in the small intestine. Two groups of male Wistar rats (young; 10-week-old, n = 40; old; 24-month-old, n = 40) underwent either a jejunal transection and reanastomosis or 90% proximal small bowel resection. The rats were sacrificed on the 1st, 2nd, 4th, and 7th postoperative day (POD). The mucosa was submitted for histological examination, weighed, and assayed for protein, DNA, RNA, and polyamine content. Ornithine decarboxylase (ODC) activity was measured and ODC mRNA in the mucosa was determined by Northern blot analysis. Compared with the values for wet weight and protein content in old rats, young rats showed significantly higher values for wet weight on the 1st and 2nd POD, and for protein content on the 1st POD, but there were no differences between young and old rats after the 4th POD. The values for ODC activity and ODC mRNA were significantly lower in old rats than in young rats on the 1st POD, but there were no differences between young and old rats after the 2nd POD. The value for putrescine in old rats was significantly lower on the 2nd POD, but was significantly higher on the 4th POD than that in young rats. The present study showed that, in old rats, the residual intestine after small bowel resection preserved sufficient adaptive capacity, but that the adaptive response was decreased. The findings in this study also suggest that a decrease in ODC mRNA expression is involved in the decreased adaptive response that occurs with aging.