Intestinal lengthening for short bowel syndrome

Clinical challenges of short bowel syndrome and the path forward for organoid-based regenerative medicine

Short bowel syndrome (SBS) is a rare condition, the main symptom of which is malabsorption following extensive resection of the small intestine. Treatment for SBS is mainly supportive, consisting of supplementation, prevention and treatment of complications, and promotion of intestinal adaptation. While development of parenteral nutrition and drugs promoting intestinal adaptation has improved clinical outcomes, the prognosis of patients with SBS remains poor. Intestinal transplantation is the only curative therapy but its outcome is unsatisfactory. In the absence of definitive therapy, novel treatment is urgently needed. With the advent of intestinal organoids, research on the intestine has developed remarkably in recent years. Concepts such as the "tissue-engineered small intestine" and "small intestinalized colon," which create a functional small intestine by combining organoids with other technologies, are potentially novel regenerative therapeutic approaches for SBS. Although they are still under development and there are substantial issues to be resolved, the problems that have prevented establishment of the complex function and structure of the small intestine are gradually being overcome. This review discusses the current treatments for SBS, the fundamentals of the intestine and organoids, the current status of these new technologies, and future perspectives.

ESPEN guideline on chronic intestinal failure in adults - Update 2023

BACKGROUND & AIMS

In 2016, ESPEN published the guideline for Chronic Intestinal Failure (CIF) in adults. An updated version of ESPEN guidelines on CIF due to benign disease in adults was devised in order to incorporate new evidence since the publication of the previous ESPEN guidelines.

METHODS

The grading system of the Scottish Intercollegiate Guidelines Network (SIGN) was used to grade the literature. Recommendations were graded according to the levels of evidence available as A (strong), B (conditional), 0 (weak) and Good practice points (GPP). The recommendations of the 2016 guideline (graded using the GRADE system) which were still valid, because no studies supporting an update were retrieved, were reworded and re-graded accordingly.

RESULTS

The recommendations of the 2016 guideline were reviewed, particularly focusing on definitions, and new chapters were included to devise recommendations on IF centers, chronic enterocutaneous fistulas, costs of IF, caring for CIF patients during pregnancy, transition of patients from pediatric to adult centers. The new guideline consist of 149 recommendations and 16 statements which were voted for consensus by ESPEN members, online in July 2022 and at conference during the annual Congress in September 2022. The Grade of recommendation is GPP for 96 (64.4%) of the recommendations, 0 for 29 (19.5%), B for 19 (12.7%), and A for only five (3.4%). The grade of consensus is "strong consensus" for 148 (99.3%) and "consensus" for one (0.7%) recommendation. The grade of consensus for the statements is "strong consensus" for 14 (87.5%) and "consensus" for two (12.5%).

CONCLUSIONS

It is confirmed that CIF management requires complex technologies, multidisciplinary and multiprofessional activity, and expertise to care for the underlying gastrointestinal disease and to provide HPN support. Most of the recommendations were graded as GPP, but almost all received a strong consensus.

Experiences with intestinal failure from an intestinal rehabilitation unit in a country without home parenteral nutrition

OBJECTIVE

For the first time, we reported experiences with an intestinal rehabilitation unit (IRU) from a country without home parenteral nutrition (HPN).

METHODS

We included patients with a diagnosis of intestinal failure (IF) since the establishment of our IRU from February 2018 to February 2020. We further report on our protocols for management of enterocutaneous fistulas (ECFs), short-bowel syndrome (SBS), chronic intestinal pseudo-obstruction and motility disorders.

RESULTS

Among a total of 349 patients who have been admitted, 100 patients had IF and were included . Mean (SD) age of patients was 46.3 ± 16.1 years. Most common cause of IF was ECFs (32%), SBS (24%), and SBS + fistula (22%). Most common causes of SBS were mesenteric ischemia (63.3%) and repeated surgery (22.4%). Median (interquartile range [IQR]) duration of parenteral nutrition (PN) for patients was 32 (18-60) days. The most common reconstructive surgery performed was resection and anastomosis (75.4%), followed by serial transverse enteroplasty procedure (10.5%) and closure of ostoma (7%). Patients were hospitalized for a median (IQR) of 33 (17.5-61) days. Most common complications were sepsis (45%), catheter infections (43%), and catheter thrombosis (20%), respectively. At the final follow-up, 61% stopped receiving PN, 23% became candidates for transplantation, and 16% died.

CONCLUSION

Considering that most countries lack facilities for HPN, by establishing IRUs using specific treatment protocols and autologous gastrointestinal reconstruction techniques will provide a means to manage patients with IF, thus decreasing death rates and number of patients who require intestinal transplantations due to IF.

To Wean or Not to Wean: The Role of Autologous Reconstructive Surgery in the Natural History of Pediatric Short Bowel Syndrome on Behalf of Italian Society for Gastroenterology, Hepatology and Nutrition (SIGENP)

Pediatric Short Bowel Syndrome (SBS) can require prolonged parenteral nutrition (PN). Over the years, SBS management has been implemented by autologous gastrointestinal reconstructive surgery (AGIR). The primary objective of the present review was to assess the effect of AGIR on weaning off PN. We also evaluated how AGIR impacts survival, the need for transplantation (Tx) and the development of liver disease (LD). We conducted a systematic literature search to identify studies published from January 1999 to the present and 947 patients were identified. PN alone was weakly associated with higher probability of weaning from PN (OR = 1.1, p = 0.03) and of surviving (OR = 1.05, p = 0.01). Adjusting for age, the probability of weaning off PN but of not surviving remained significantly associated with PN alone (OR = 1.08, p = 0.03). Finally, adjusting for age and primary diagnosis (gastroschisis), any association was lost. The prevalence of TX and LD did not differ by groups. In conclusion, in view of the low benefit in terms of intestinal adaptation and of the not negligible rate of complications (20%), a careful selection of candidates for AGIR should be required. Bowel dilation associated with failure of advancing EN and poor growth, should be criteria to refer for AGIR.

Short Bowel Syndrome as the Leading Cause of Intestinal Failure in Early Life: Some Insights into the Management

Intestinal failure (IF) is the critical reduction of the gut mass or its function below the minimum needed to absorb nutrients and fluids required for adequate growth in children. Severe IF requires parenteral nutrition (PN). Pediatric IF is most commonly due to congenital or neonatal intestinal diseases or malformations divided into 3 groups: 1) reduced intestinal length and consequently reduced absorptive surface, such as in short bowel syndrome (SBS) or extensive aganglionosis; 2) abnormal development of the intestinal mucosa such as congenital diseases of enterocyte development; 3) extensive motility dysfunction such as chronic intestinal pseudo-obstruction syndromes. The leading cause of IF in childhood is the SBS. In clinical practice the degree of IF may be indirectly measured by the level of PN required for normal or catch up growth. Other indicators such as serum citrulline have not proven to be highly reliable prognostic factors in children. The last decades have allowed the development of highly sophisticated nutrient solutions consisting of optimal combinations of macronutrients and micronutrients as well as guidelines, promoting PN as a safe and efficient feeding technique. However, IF that requires long-term PN may be associated with various complications including infections, growth failure, metabolic disorders, and bone disease. IF Associated Liver Disease may be a limiting factor. However, changes in the global management of IF pediatric patients, especially since the setup of intestinal rehabilitation centres did change the prognosis thus limiting "nutritional failure" which is considered as a major indication for intestinal transplantation (ITx) or combined liver-ITx.

Emerging treatments for short bowel syndrome in adult patients

Short bowel syndrome (SBS) is the major cause of chronic intestinal failure (IF), defined as 'the reduction of gut function below the minimum necessary for the absorption of macronutrients and/or water and electrolytes, such that intravenous supplementation is required to maintain health and/or growth'. Areas covered: Spontaneous intestinal adaptation, including increased hormonal secretion, development of hyperphagia and gut microbiota dysbiosis, occurs 2 years after resection, improving intestinal absorption and decreasing PN dependency. Hormonal treatments, promoting intestinal hyperadaptation, have been proposed in patients with SBS with chronic IF. Clinical studies showed teduglutide to increase urine production and reduce the need for parenteral support volume in these patients. According to the latest ESPEN Guidelines, if a growth factor treatment is considered, the GPL2 analog, teduglutide, should be the first-choice treatment. Expert opinion: These therapies underline the importance of patient monitoring at home and the complexity for HPN adaptation. A multidisciplinary approach should be a gold standard.

Surgical strategies in short bowel syndrome

Extensive loss of small bowel in all age groups has significant morbidity and mortality consequences. Despite the astonishing ability of the small bowel to compensate for an extensive loss, long-term parenteral nutrition and enteral nutrition, tailored to the need of the patients in relation to the missing intestinal regions is needed. Organ-preserving surgical intervention becomes necessary in patients with a very short intestinal transit time and in an other group of patients with impaired propulsive peristalsis. Intestinal transplantation is indicated in recurrent septical infections or if nearly all of the small bowel is missing. This review discusses indications and risks of the organ-preserving surgical therapies in children with short bowel syndrome.

ESPEN guidelines on chronic intestinal failure in adults

BACKGROUND & AIMS

Chronic Intestinal Failure (CIF) is the long-lasting reduction of gut function, below the minimum necessary for the absorption of macronutrients and/or water and electrolytes, such that intravenous supplementation is required to maintain health and/or growth. CIF is the rarest organ failure. Home parenteral nutrition (HPN) is the primary treatment for CIF. No guidelines (GLs) have been developed that address the global management of CIF. These GLs have been devised to generate comprehensive recommendations for safe and effective management of adult patients with CIF.

METHODS

The GLs were developed by the Home Artificial Nutrition & Chronic Intestinal Failure Special Interest Group of ESPEN. The GRADE system was used for assigning strength of evidence. Recommendations were discussed, submitted to Delphi rounds, and accepted in an online survey of ESPEN members.

RESULTS

The following topics were addressed: management of HPN; parenteral nutrition formulation; intestinal rehabilitation, medical therapies, and non-transplant surgery, for short bowel syndrome, chronic intestinal pseudo-obstruction, and radiation enteritis; intestinal transplantation; prevention/treatment of CVC-related infection, CVC-related occlusion/thrombosis; intestinal failure-associated liver disease, gallbladder sludge and stones, renal failure and metabolic bone disease. Literature search provided 623 full papers. Only 12% were controlled studies or meta-analyses. A total of 112 recommendations are given: grade of evidence, very low for 51%, low for 39%, moderate for 8%, and high for 2%; strength of recommendation: strong for 63%, weak for 37%.

CONCLUSIONS

CIF management requires complex technologies, multidisciplinary and multiprofessional activity, and expertise to care for both the underlying gastrointestinal disease and to provide HPN support. The rarity of the condition impairs the development of RCTs. As a consequence, most of the recommendations have a low or very low grade of evidence. However, two-thirds of the recommendations are considered strong. Specialized management and organization underpin these recommendations.

Short Bowel Syndrome and Malabsorption - Causes and Prevention

Background

The short bowel syndrome (SBS) is a condition caused by extensive intestinal resection for a variety of conditions. The etiology varies by age group. Necrotizing enterocolitis is the leading cause in infants. In older children, trauma and malignancies are most common. Postoperative SBS has become most common in adults, followed by mesenteric vascular disease and cancer/irradiation.

Methods

Systematic literature review.

Results

Prevention of SBS should be given high priority. Each of the etiologies has been evaluated and strategies to prevent extensive resection have been developed. These include a thoughtful approach to reoperation, early identification of complications, e.g. intestinal ischemia, reducing radiation enteritis, and bowel-conserving therapies in diseases such as Crohn's disease.

Conclusion

Several operative strategies to prevent SBS are useful. Timing and extent of reoperation need careful consideration. Minimizing intestinal resection, bowel-conserving techniques for complications such as fistula or strictures, and remodeling procedures are important.

The Surgical Approach to Short Bowel Syndrome - Autologous Reconstruction versus Transplantation

BACKGROUND

Short bowel syndrome (SBS) is a state of malabsorption resulting from massive small bowel resection leading to parenteral nutrition (PN) dependency. Considerable advances have been achieved in the medical and surgical management of SBS over the last few decades.

METHODS

This review discusses in detail the surgical approach to SBS.

RESULTS

Widespread use of PN enables long-term survival in patients with intestinal failure but at the cost of PN-associated life-threatening complications including catheter-associated blood stream infection, venous thrombosis, and liver disease. The goal of management of intestinal failure due to SBS is to enable enteral autonomy and wean PN by means of a multi-disciplinary approach. Availability of modified enteral feeding formulas have simplified nutrition supplementation in SBS patients. Similarly, advances in the medical field have made medications like growth hormone and glucagon-like peptide (GLP2) available to improve water and nutrient absorption as well as to enable achieving enteral autonomy. Autologous gastrointestinal reconstruction (AGIR) includes various techniques which manipulate the bowel surgically to facilitate the bowel adaptation process and restoration of enteral nutrition. Ultimately, intestinal transplantation can serve as the last option for the cure of intestinal failure when selectively applied.

CONCLUSION

SBS continues to be a challenging medical problem. Best patient outcomes can be achieved through an individualized plan, using various AGIR techniques to complement each other, and intestinal transplantation as a last resort for cure. Maximum benefit and improved outcomes can be achieved by caring for SBS patients at highly specialized intestinal rehabilitation centers.

Intestinal transplant registry report: global activity and trends

The Registry has gathered information on intestine transplantation (IT) since 1985. During this time, individual centers have reported progress but small case volumes potentially limit the generalizability of this information. The present study was undertaken to examine recent global IT activity. Activity was assessed with descriptive statistics, Kaplan-Meier survival curves and a multiple variable analysis. Eighty-two programs reported 2887 transplants in 2699 patients. Regional practices and outcomes are now similar worldwide. Current actuarial patient survival rates are 76%, 56% and 43% at 1, 5 and 10 years, respectively. Rates of graft loss beyond 1 year have not improved. Grafts that included a colon segment had better function. Waiting at home for IT, the use of induction immune-suppression therapy, inclusion of a liver component and maintenance therapy with rapamycin were associated with better graft survival. Outcomes of IT have modestly improved over the past decade. Case volumes have recently declined. Identifying the root reasons for late graft loss is difficult due to the low case volumes at most centers. The high participation rate in the Registry provides unique opportunities to study these issues.

Non-transplant surgery for short bowel syndrome

The goal of any treatment programme for short bowel syndrome SBS is to achieve nutritional enteral autonomy. This must begin with conservation of as much bowel as possible from the time of first presentation. Frequent causes of the short bowel syndrome are intestinal atresia, necrotizing enterocolitis, midgut volvulus, extended intestinal aganglionosis, 'vanished gut' often associated with gastroschisis and occasionally catastrophic trauma. Atresia is more amenable to successful surgery than other causes, except when associated with gastroschisis. Intrinsic dysmotility has a poor prognosis. Intestinal lengthening procedures are only indicated if there is sufficient bowel dilatation. Extended intestinal aganglionosis is rarely amenable to any form of non-transplant surgery. Options available are to conserve bowel, close stomas early (use all available bowel to the maximum or even re-feed stoma effluent into the distal unused bowel), release adhesions causing obstruction, resect strictures, taper or excise localized dilatations and finally address dilated bowel with lengthening and tailoring operations. These procedures aim to improve effective peristalsis, thereby reducing bacterial overgrowth and improving nutrient contact with enteral mucosa to maximize absorption and intestinal adaptation. The Bianchi longitudinal splicing operation and the serial transverse enteroplasty operations have stood the test of time in providing considerable improvement in enteral nutritional autonomy in around 60% of cases. In SBS without dilatation attempts at 'mechanically' delaying transit (nipple valves, reversed bowel segments, colon interposition) have had inconsistent outcomes. Growing neomucosa and lengthening bowel by longitudinal stretch are still experimental.

Mechanical elongation of the small intestine: evaluation of techniques for optimal screw placement in a rodent model

Introduction. The aim of this study was to evaluate techniques and establish an optimal method for mechanical elongation of small intestine (MESI) using screws in a rodent model in order to develop a potential therapy for short bowel syndrome (SBS). Material and Methods. Adult female Sprague Dawley rats (n = 24) with body weight from 250 to 300 g (Σ = 283) were evaluated using 5 different groups in which the basic denominator for the technique involved the fixation of a blind loop of the intestine on the abdominal wall with the placement of a screw in the lumen secured to the abdominal wall. Results. In all groups with accessible screws, the rodents removed the implants despite the use of washers or suits to prevent removal. Subcutaneous placement of the screw combined with antibiotic treatment and dietary modifications was finally successful. In two animals autologous transplantation of the lengthened intestinal segment was successful. Discussion. While the rodent model may provide useful basic information on mechanical intestinal lengthening, further investigations should be performed in larger animals to make use of the translational nature of MESI in human SBS treatment.

Comparison of LILT and STEP procedures in children with short bowel syndrome -- a systematic review of the literature

PURPOSE

To compare LILT and STEP, the two principal procedures to lengthen the native bowel in children with a short bowel syndrome (SBS), by discussing the indications and presenting the outcome from published data.

METHODS

A review of literature was performed. N=39 publications were reviewed.

RESULTS

For LILT and STEP, failure to achieve intestinal autonomy by conservative therapy represents the main indication, and end-stage liver disease the main contraindication. A sufficiently dilated intestinal segment is a common anatomical precondition for both procedures. STEP can be performed on shorter intestinal segments and on intricate segments such as the duodenum, which is technically not feasible for LILT. Both procedures have a similar extent of intestinal lengthening (approximately 70%) and result in improvement of enteral nutrition and reversal of complications of parenteral nutrition. STEP seems to have a lower mortality and overall progression to transplantation.

CONCLUSIONS

STEP and LILT are both accepted procedures for non-transplant surgical management of SBS in children. The outcome after STEP seems to be more favourable, but larger series are needed to further assess accurate selection of eligible patients and to estimate effectiveness of procedures. A considerably higher number of cases for evaluation might be accomplished through the widespread use of a centralised registry.

Intestinal failure in children: the European view

Intestinal failure (IF) is a condition in which severe intestinal malabsorption mandates artificial nutrition through a parenteral route. Causes of severe protracted IF include short bowel syndrome, congenital diseases of enterocyte development, and severe motility disorders (total or subtotal aganglionosis or chronic intestinal pseudo-obstruction syndrome). IF can result in nutritional failure, defined as the long-term failure to nourish a child by natural or artificial means. Today, IF-associated liver disease is the most common cause of parenteral nutrition (PN) failure, but catheter-related sepsis and extensive vascular thrombosis may also jeopardize the health of those receiving PN. For a child with nutritional failure, intestinal transplantation, often in the form of a composite visceral graft, offers the only chance for long-term survival. The management of IF requires a multidisciplinary approach. There have been a number of recent advances in both medical and surgical treatments of IF. In particular, new intestinal lengthening techniques and the use of PN formulas rich in fish oil both have resulted in decreased rates of severe complications of IF and its treatments. In addition, better awareness of the risks and benefits of intestinal transplantation have resulted in better patient selection, and ultimately in improved patient survival, hence restricting the indication to transplantation only to patients with nutritional failure and no other chance to survive.

Long-term survival, nutritional autonomy, and quality of life after intestinal and multivisceral transplantation

OBJECTIVE

To assess long-term survival, graft function, and health-related quality of life (QOL) after visceral transplantation.

BACKGROUND

Despite continual improvement in early survival, the long-term therapeutic efficacy of visceral transplantation has yet to be defined.

METHODS

A prospective cross-sectional study was performed on 227 visceral allograft recipients who survived beyond the 5-year milestone. Clinical data were used to assess outcome including graft function and long-term survival predictors. The socioeconomic milestones and QOL measures were assessed by clinical evaluation, professional consultation, and validated QOL inventory.

RESULTS

Of 376 recipients, 227 survived beyond 5 years, with conditional survival of 75% at 10 years and 61% at 15 years. With a mean follow-up of 10 ± 4 years, 177 (92 adults, 85 children) are alive, with 118 (67%) recipients 18 years or older. Nonfunctional social support and noninclusion of the liver in the visceral allograft are the most significant survival risk factors. Nutritional autonomy was achievable in 160 (90%) survivors, with current serum albumin level of 3.7 ± 0.5 gm/dL and body mass index of 25 ± 6 kg/m(2). Despite coexistence or development of neuropsychiatric disorders, most survivors were reintegrated to society with self-sustained socioeconomic status. In parallel, most of the psychological, emotional, and social QOL measures significantly (P < 0.05) improved after transplantation. Current morbidities with potential impact on global health included dysmotility (59%), hypertension (37%), osteoporosis (22%), and diabetes (11%), with significantly (P < 0.05) higher incidence among adult recipients.

CONCLUSIONS

With new tactics to further improve long-term survival including social support measures, visceral transplantation has achieved excellent nutritional autonomy and good QOL.

Neonatal short bowel syndrome as a model of intestinal failure: physiological background for enteral feeding

Intestinal failure (IF) is a well identified clinical condition, which is characterised by the reduction of functional gut capacity below the minimum needed for adequate digestion and absorption of nutrients for normal growth in children. Short bowel syndrome (SBS) is the leading cause of IF in neonates, infants and young children usually as a result of extensive intestinal resection during the neonatal period. Simultaneously maintaining optimal nutritional status and achieving intestinal adaptation is a clinical challenge in short bowel patients. Both growth and development of the child as well as gut adaptation should be considered synergistically as primary outcome parameters. Enteral nutrition (EN) can be introduced orally and/or by tube feeding (TF). Several controversies over nutritional treatment of children with SBS related intestinal failure remain. As reported from different centres around the world, most practices are more "experienced based" rather than "evidence based". This is partly due to the small number of patients with this condition. This review (based on a consensus) discusses the physiological principles and nutritional management, including the type of diet and route of delivery. Perspectives in optimizing intestinal adaptation and reducing the consequences of small intestinal bacterial overgrowth are also discussed.

Short bowel syndrome

The short bowel syndrome (SBS) is a state of malabsorption following intestinal resection where there is less than 200 cm of intestinal length. The management of short bowel syndrome can be challenging and is best managed by a specialised multidisciplinary team. A good understanding of the pathophysiological consequences of resection of different portions of the small intestine is necessary to anticipate and prevent, where possible, consequences of SBS. Nutrient absorption and fluid and electrolyte management in the initial stages are critical to stabilisation of the patient and to facilitate the process of adaptation. Pharmacological adjuncts to promote adaptation are in the early stages of development. Primary restoration of bowel continuity, if possible, is the principle mode of surgical treatment. Surgical procedures to increase the surface area of the small intestine or improve its function may be of benefit in experienced hands, particularly in the paediatric population. Intestinal transplant is indicated at present for patients who have failed to tolerate long-term parenteral nutrition but with increasing experience, there may be a potentially expanded role for its use in the future.