Sandostatin impairs postresection intestinal adaptation in a rat model of short bowel syndrome

Current fistula management

PURPOSE OF REVIEW

Enterocutaneous fistulas (ECFs) pose a significant impact in the healthcare system, both financially and in resource utilization. Delivery of optimal care is complex and involves intensive wound care, complex nutritional delivery and multidisciplinary care teams for optimization. Recently, there have been pushes to modernize the traditional approach to ECF care to a new paradigm of protocol-based individualized delivery of care.

RECENT FINDINGS

There is an increased trend towards pushing enteral nutrition for the management of ECF patients. Adjuncts, including improved fistuloclysis devices, supplements and absorptive aides have challenged the conventional dogma of ECF treatment. There has also been increased focus on surgical prehabilitation and the ability to improve patient outcomes.

SUMMARY

ECF care is complex and requires a multidisciplinary approach focused on source control, nutritional optimization with focus on enteral nutrition, wound care and prehabilitation.

Management of Short Bowel Syndrome (SBS) and Intestinal Failure

Short bowel syndrome (SBS) is a chronic disease whose natural history requires a changing array of management strategies over time. Chief amongst these is the chronic use of parenteral nutrition (PN) to ensure adequate nutritional intake. With time and appropriate management, approximately half of all SBS patients will successfully regain a functional, baseline level of intrinsic bowel function that will allow for them to achieve PN independence. However, the other half of SBS patients will progress into chronic intestinal failure which warrants a change in therapy to include more aggressive medical and potentially surgical measures. This review examines the evolving treatment strategies involved in the management of SBS as well as intestinal failure.

Weaning from Parenteral Nutrition

The ultimate goal of treatment of short bowel syndrome/intestinal failure patients is to achieve enteral autonomy by eliminating parenteral nutrition (PN)/intravenous fluids (IV). After optimization of diet, oral hydration and anti-diarrheal medications, attempt should be made to eliminate PN/IV. Weaning from PN/IV should be individualized for each patient. Although teduglutide is the preferred agent for PN/IV volume reduction or successful weaning, optimal patient selection and long-term safety need further evaluation. Following PN/IV elimination, patients need long-term monitoring for nutritional deficiencies. This article will address clinical considerations before, during, and after PN/IV weaning to facilitate safe and successful PN/IV weaning process.

Intestinal Failure and Rehabilitation

The rendering of proper care for the patient with intestinal failure requires the provider to have a functional understanding of digestion and absorption, nutrient requirements, and intestinal adaptation. Inherent in those concepts is that not only is nutritional absorption compromised, but medication absorption is as well. The principles of the management of home parenteral nutrition must be mastered and then proper and controlled weaning of parenteral nutrition may be commenced by use of dietary and pharmacologic means with appropriate clinical outcome measures followed. This complicated management requires a team experienced in both medical and surgical management of intestinal failure.

Management and Complications of Short Bowel Syndrome: an Updated Review

Short bowel syndrome (SBS) is defined as loss of bowel mass from surgical resection, congenital defects, or disease. Intestinal failure (IF) includes the subset of SBS unable to meet nutrition needs with enteral supplements and requires parenteral nutrition (PN). The parenteral treatment of SBS is now a half-century old. Recent pharmacologic treatment (GLP-2 analogues) has begun to make a significant impact in the care and ultimate management of these patients such that the possibility of reducing PN requirements in formerly PN-dependent patients is a now a real possibility. Finally, newer understanding and possible treatment for some of the complications related to IF have more recently evolved and will be an emphasis of this report. This review will focus on developments over the last 10 years with the goal of updating the reader to new advances in our understanding of the care and feeding of the SBS patient.

A review of enteral strategies in infant short bowel syndrome: evidence-based or NICU culture?

INTRODUCTION

Short bowel syndrome (SBS) is an increasingly common condition encountered across neonatal intensive care units. Improvements in parenteral nutrition (PN), neonatal intensive care and surgical techniques, in addition to an improved understanding of SBS pathophysiology, have contributed in equal parts to the survival of this fragile subset of infants. Prevention of intestinal failure associated liver disease (IFALD) and promotion of intestinal adaptation are primary goals of all involved in the care of these patients. While enteral nutritional and pharmacological strategies are necessary to achieve these goals, there remains great variability in the application of therapeutic strategies in units that are not necessarily evidence-based.

MATERIALS AND METHODS

A search of major English language medical databases (SCOPUS, Index Medicus, Medline, and the Cochrane database) was conducted for the key words short bowel syndrome, medical management, nutritional management and intestinal adaptation. All pharmacological and nutritional agents encountered in the literature search were classified based on their effects on absorptive capacity, intestinal adaptation and bowel motility that are the three major strategies employed in the management of SBS. The Oxford Center for Evidence-Based Medicine (CEBM) classification for levels of evidence was used to develop grades of clinical recommendation for each variable studied.

RESULTS

We reviewed various medications used and nutritional strategies included soluble fiber, enteral fat, glutamine, probiotics and sodium supplementation. Most interventions have scientific rationale but little evidence to support their role in the management of infant SBS. While some of these agents symptomatically improve diarrhea, they can adversely influence pancreatico-biliary function or actually impair intestinal adaptation. Surgical anatomy and liver function are two important variables that should determine the selection of pharmacological and nutritional interventions.

DISCUSSION

There is a paucity of research investigating optimal clinical practice in infant SBS and the little evidence available is consistently of lower quality, resulting in a wide variation of clinical practices among NICUs. Prospective trials should be encouraged to bridge the evidence gap between research and clinical practice to promote further progress in the field.

Role of octreotide in post chemotherapy and/or radiotherapy diarrhea: prophylaxis or therapy?

AIM

The clinical efficacy of octreotide in controlling chemoradiotherapy-induced diarrhea remains controversial. We conducted a meta-analysis of randomized controlled trials (RCT) comparing octreotide with placebo in the prevention or therapy of chemoradiotherapy-induced diarrhea.

METHODS

A computerized literature search of Medline, EMBASE, Cochrane Library and BIOSIS databases were performed for RCT comparing the use of octreotide versus placebo in the management of patients with chemoradiotherapy-induced diarrhea. The main outcome measure was the response of the diarrhea.

RESULTS

We included eight RCT comprising 572 patients. We found octreotide was significantly effective compared with the placebo (OR, 4.9; 95%, 1.58-15.2).The overall effect of octreotide was 69% (204/294), while that of placebo was 54% (149/278). When divided into prophylactic and therapeutic subgroups, the prophylactic subgroup had an OR of 2.11 (95% CI, 0.51-2.89) for chemoradiotherapy-induced diarrhea and the therapeutic subgroup had an OR of 7.30 (95% CI, 4.09-13.04).

CONCLUSION

In chemoradiotherapy-induced diarrhea, octreotide is best used as a therapeutic rather than a prophylactic agent against diarrhea.

Complications of enterocutaneous fistulas and their management

Complications related to enterocutaneous fistulas are common and include sepsis, malnutrition, and fluid or electrolyte abnormalities. Intestinal failure is one of the most feared complications of enterocutaneous fistula management and results in significant patient morbidity and mortality. The authors review emerging trends in the medical and surgical management of patients with intestinal failure.

Intestinal failure: A new era in clinical management

Only 50 years ago intestinal failure was considered incompatible with life. Since then, developments in parenteral nutrition, and, more recently, small intestinal transplantation, have provided new therapeutic options with the potential to offer long-term survival with a good quality of life. Current medical and surgical strategies are aimed at enhancing intestinal adaptation, improving absorption to achieve nutritional independence, and minimizing the complications of parenteral nutrition therapy. An integrated, multidisciplinary approach to the management of patients with intestinal failure, closely linked to a transplantation program to facilitate early referral, is recognized as a key factor in optimizing patient outcomes.

Clonidine reduces diarrhea and sodium loss in patients with proximal jejunostomy: a controlled study

BACKGROUND

Patients with short bowel syndrome have significant fluid losses. This represents a significant management problem, especially in patients with minimal residual intestine. We determined whether clonidine, an alpha2-adrenergic agonist, is effective in decreasing fecal water and sodium (Na) losses in patients with proximal jejunostomy. Eight parenteral nutrition (PN)-dependent subjects (3 men, 5 women), aged 49.9+/-10.2 years, with a residual small bowel length of 71.8+/-152.0 cm that ended in a jejunostomy, were studied.

METHODS

Subjects were admitted to the North-western General Clinical Research Center (GCRC) for a 2-day equilibrium period while receiving a self-selected 100 g fat diet with protein 1.5 g/kg/d and 30 kcal/kg/d and 1 L/d of oral rehydration solution. A D-xylose test was performed after an overnight fast. On days 3-5, all stool and urine were collected for volume, weight, fat, nitrogen, energy, sodium, magnesium, potassium, and calcium. Meals were provided in duplicate and the equivalent portions consumed by each patient were analyzed for fluid volume, fat, nitrogen, energy, sodium, magnesium, calcium, and potassium in order to calculate nutrient balances. At the conclusion of the stool and urine collections (day 6), a clonidine (0.3 mg) patch was applied to the shoulder. Subjects were restudied after 1 week.

RESULTS

Daily fecal volume and weight were 4.514+/-1.769 L/d and 4394+/-1727 g/d, respectively, at baseline. Five subjects were net "secretors" in that excreted fecal volume exceeded oral intake. Fecal volume decreased by 427+/-562 mL/d (8.9%, p=.07). Fecal weight decreased by 438+/-527 g/d (9.4%, p=.05). Urine volume correspondingly increased by 747+/-1934 mL (18.9%, p=not significant [NS]). The increase in urine output was weakly and negatively correlated with the decrease in fecal volume and weight (r=-0.37 and -0.41, respectively, p=NS). Oral fluid intake decreased slightly from 3.328+/-1.246 L/d baseline to 3.203+/-1.119 L/d with clonidine therapy (-3.8%, p=NS). Fecal Na loss was significantly decreased from baseline (887+/-996 mg/d, 11.2+/-12.3%; p=.036). This was not related to decreased oral Na intake, which actually increased from baseline (3.799+/-2.271 g/d) to 3.933+/-1.314 g/d after clonidine therapy (p=NS). No patient developed hypotension.

CONCLUSIONS

Our results show the transdermal administration of clonidine is associated with a modest but clinically significant decrease in fecal output in patients with short bowel syndrome and high-output proximal jejunostomy that require chronic parenteral fluid infusion. This is accompanied by decreased fecal Na loss.

Dietary and medical management of short bowel syndrome in adult patients

Resection of the small bowel can lead to malabsorption of fluid, electrolytes, minerals, and other essential nutrients, resulting in malnutrition and dehydration. Individualized and tailored nutritional management for patients with short bowel syndrome (SBS) helps to optimize intestinal absorption, leading to nutritional independence such that a patient can resume as normal a lifestyle as possible. Parenteral nutrition (PN), used to supply the required nutrients following resection, is associated with a number of complications affecting patient morbidity and mortality. Attempts should be made to wean patients from PN to an oral diet as soon as possible. Dietary management is complex and needs to be individualized for each patient on the basis of his or her specific gastrointestinal anatomy, underlying disease, and lifestyle. In addition to nutrient intake, management of SBS also requires appropriate oral rehydration, vitamin and mineral supplementation, and pharmacotherapy. Several medications provide a useful adjunctive function to dietary intervention, including antidiarrheal agents, H2 antagonists and proton pump inhibitors, pancreatic enzymes, somatostatin analogs, antimicrobials, and trophic factors.

Advances in short bowel syndrome: an updated review

Short bowel syndrome (SBS) continues to be an important clinical problem due to its high mortality and morbidity as well as its devastating socioeconomic effects. The past 3 years have witnessed many advances in the investigation of this condition, with the aim of elucidating the cellular and molecular mechanisms of intestinal adaptation. Such information may provide opportunities to exploit various factors that act as growth agents for the remaining bowel mucosa and may suggest new therapeutic strategies to maintain gut integrity, eliminate dependence on total parenteral nutrition, and avoid the need for intestinal transplantation. This review summarizes current research on SBS over the last few years.

Parenteral arginine impairs intestinal adaptation following massive small bowel resection in a rat model

The nitric oxide precursor L-arginine (ARG) has been shown to influence intestinal structure and absorptive function. It is also well known that the route of administration modulates the effects of ARG. The present study evaluated the effects of parenteral ARG on structural intestinal adaptation, cell proliferation, and apoptosis in a rat model of short bowel syndrome (SBS). Male Sprague-Dawley rats were divided into three experimental groups: Sham rats underwent bowel transection and reanastomosis, SBS rats underwent a 75% small bowel resection, and SBS-ARG rats underwent a 75% small bowel resection and were treated with ARG given subcutaneously at a dose of 300 mug/kg, once daily, from days 3 to 14. Parameters of intestinal adaptation, enterocyte proliferation, and enterocyte apoptosis were determined on day 15 following operation. The SBS rats demonstrated a significant increase in jejunal and ileal bowel and mucosal weight, villus height and crypt depth, and cell proliferation index compared with the sham group. The SBS-ARG animals demonstrated lower ileal bowel and mucosal weights, jejunal mucosal DNA and ileal mucosal protein, and jejunal and ileal villus height and crypt depth compared with SBS animals. The SBS-ARG rats also had a lower cell proliferation index in both jejunum and ileum and a greater enterocyte apoptotic index in ileum compared with the SBS-untreated group. In conclusion, in a rat model of SBS, parenteral arginine inhibits structural intestinal adaptation. Decreased cell proliferation and increased apoptosis are the main mechanisms responsible for decreased cell mass.

Effect of sex and sex hormones on structural intestinal adaptation after massive small bowel resection in rats

PURPOSE

The gonadal steroids play a major role in the regulation of many functions. The purpose of the current study was to evaluate the effect of sex and sex hormones on intestinal adaptation in a rat model of short bowel syndrome (SBS).

METHODS

In the first experiment, male and female Sprague-Dawley rats underwent bowel transection and re-anastomosis (sham group) or 75% small bowel resection and anastomosis (SBS group). Relative changes in parameters of intestinal adaptation (overall bowel and mucosal weight, mucosal DNA and protein, villus height, and crypt depth) were measured on day 15 and were compared with respect to sex. In the second experiment, male rats were divided into 4 experimental groups: SBS rats, SBS castrated rats, SBS castrated rats treated with testosterone, and SBS castrated rats treated with estradiol. Parameters of intestinal adaptation were compared with respect to hormonal treatment. Statistical significance was determined by Student's t test and analysis of variance with P < .05 considered significant.

RESULTS

Sex had minimal effects on intestinal adaptation. Both male and female rats showed a comparable increase in all parameters of intestinal adaptation. In the second experiment, castration led to significant decrease in bowel and mucosal weight, mucosal DNA and protein in both jejunum and ileum compared with SBS animals. Castrated rats also had lower jejunal villus height and crypt depth compared with SBS animals. Testosterone attenuated this negative effect of castration on bowel regrowth. Rats treated with testosterone showed a significant increase in bowel and mucosal weight, mucosal protein in both jejunum and ileum, mucosal DNA, villus height, and crypt depth in jejunum compared with castrated nontreated animals. Treatment with estradiol after resection and castration had minimal effect on bowel regrowth.

CONCLUSIONS

Bowel regrowth after massive small bowel resection is not sex-related. Depletion of androgens by castration inhibited intestinal adaptation. Testosterone has shown a strong stimulating effect on bowel regrowth.

Intestinal rehabilitation and the short bowel syndrome: part 2

The management of patients with intestinal failure due to short bowel syndrome is complex, requiring a comprehensive approach that frequently necessitates long-term, if not life-long, use of parenteral nutrition. Despite tremendous advances in the provision of parenteral nutrition over the past three decades, which have allowed significant improvements in the survival and quality of life of these patients, this mode of nutritional support carries with it significant risks to the patient, is very costly, and ultimately, does not attempt to improve the function of the remaining bowel. Intestinal rehabilitation refers to the process of restoring enteral autonomy, and thus, allowing freedom from parenteral nutrition, usually by means of dietary, medical, and occasionally, surgical strategies. While recent investigations have focused on the use of trophic substances to increase the absorptive function of the remaining gut, whether intestinal rehabilitation occurs as a consequence of enhanced bowel adaptation or is simply a result of an optimized, comprehensive approach to the care of these patients remains unclear. In Part 1 of this review, we provided an overview of short bowel syndrome and pathophysiological considerations related to the remaining bowel anatomy in these patients. We also reviewed intestinal adaptation and factors that may enhance the adaptive process, focusing on evidence derived from animal studies. In Part 2, relevant data on the development of intestinal adaptation in humans are reviewed as is the general management of short bowel syndrome. Lastly, the potential benefits of a multidisciplinary intestinal rehabilitation program in the care of these patients are also discussed.

Intestinal rehabilitation and the short bowel syndrome: part 1

The management of patients with intestinal failure due to short bowel syndrome (SBS) is complex, requiring a comprehensive approach that frequently necessitates long-term, if not life-long, use of parenteral nutrition (PN). Despite tremendous advances in the provision of PN over the past three decades, which have allowed significant improvements in the survival and quality of life of these patients, this mode of nutritional support carries with it significant risks to the patient, is very costly and, ultimately, does not attempt to improve the function of the remaining bowel. Intestinal rehabilitation refers to the process of restoring enteral autonomy and, thus, allowing freedom from parenteral nutrition, usually by means of dietary, medical, and, occasionally, surgical strategies. While recent investigations have focused on the use of trophic substances to increase the absorptive function of the remaining gut, whether intestinal rehabilitation occurs as a consequence of enhanced bowel adaptation or is simply a result of an optimized, comprehensive approach to the care of these patients remains unclear. In Part 1 of this review, an overview of SBS and pathophysiological considerations related to the remaining bowel anatomy in these patients will be provided. Additionally, a review of intestinal adaptation and factors that may enhance the adaptive process, focusing on evidence derived from animal studies, will also be discussed. In Part 2, relevant data on the development of intestinal adaptation in studies involving humans will be reviewed as will the general management of SBS. Lastly, the potential benefits of a multidisciplinary intestinal rehabilitation program in the care of these patients will also be discussed.

Enteral and parenteral nutrition in the care of patients with short-bowel syndrome

Short-bowel syndrome is a challenging entity for the gastroenterologist, requiring integration of medical, nutritional, surgical and psychological therapies. Treatment must be based on the patient's age, remaining gastrointestinal anatomy, baseline nutritional status and underlying general health as well as the numerous complications which may arise. This chapter reviews physiological alterations that occur with short-bowel syndrome and how therapies can be tailored to most adequately meet the needs of these patients. Emphasis on early stages of therapy to enhance intestinal adaptation is focused on as management during this time has a significant impact on the long-term outcome of these patients.

Enterocyte apoptosis after enterectomy in mice is activated independent of the extrinsic death receptor pathway

Intestinal adaptation following small bowel resection (SBR) is associated with greater rates of enterocyte apoptosis by unknown mechanism(s). Because postresection adaptation is associated with increased translocation of luminal bacteria, we sought to characterize the role for the extrinsic, death receptor pathway for the activation of enterocyte apoptosis after massive SBR. We first performed SBR or sham operations in mice, and the temporal expression of caspases 8, 9, and 3, death receptors tumor necrosis factor receptor-1 (TNFR1) and Fas and corresponding ligands (TNF and Fas ligand) was determined in the remnant intestine at various postoperative time points. Ileal TNFR1 and Fas expression were then measured after SBR in the setting of increased (waved-2 mice) or decreased (exogenous EGF administration) apoptosis. Finally, intestinal adaptation and apoptosis were recorded in the remnant ileum after SBR in TNFR1-null and Fas-null mice. The expression of death receptor family proteins and caspases demonstrated only modest changes after SBR and did not correlate with the histological appearance of apoptosis. In the setting of accelerated apoptosis, TNFR1 and Fas expression were paradoxically decreased. Apoptotic and adaptive responses were preserved in both TNFR1-null and Fas-null mice. These results suggest that the mechanism for increased enterocyte apoptosis following massive SBR does not appear to involve the extrinsic, death receptor-mediated pathway.