Colostrum supplementation restores insulin-like growth factor -1 levels and alters muscle morphology following massive small bowel resection

Nutritional and health effects of bovine colostrum in neonates

High concentrations of immunoglobulins, bioactive peptides, and growth factors are found in bovine colostrum (BC), the milk produced by cows in the first few days after parturition. Various biological functions make it increasingly used to provide nutritional support and immune protection to the offspring of many species, including humans. These biological functions include cell growth stimulation, anti-infection, and immunomodulation. The primary components and biological functions of colostrum were reviewed in the literature, and the authors also looked at its latent effects on the growth and development of neonates as well as on conditions such as infections, necrotizing enterocolitis, short bowel syndrome, and feeding intolerance. The importance of BC in neonatal nutrition, immune support, growth and development, and gut health has been demonstrated in a number of experimental and animal studies. BC has also been shown to be safe at low doses without adverse effects in newborns. BC supplementation has been shown to be efficient in preventing several disorders, including rotavirus diarrhea, necrotizing enterocolitis, and sepsis in animal models of prematurity and some newborn studies. Therefore, BC supplementation should be considered in cases where maternal milk is insufficient or donor milk is unavailable. The optimal age, timing, dosage, and form of BC administration still require further investigation.

An Overview of Short-Bowel Syndrome in Pediatric Patients: Focus on Clinical Management and Prevention of Complications

Short-bowel syndrome (SBS) in pediatric age is defined as a malabsorptive state, resulting from congenital malformations, significant small intestine surgical resection or disease-associated loss of absorption. SBS is the leading cause of intestinal failure in children and the underlying cause in 50% of patients on home parental nutrition. It is a life-altering and life-threatening disease due to the inability of the residual intestinal function to maintain nutritional homeostasis of protein, fluid, electrolyte or micronutrient without parenteral or enteral supplementation. The use of parenteral nutrition (PN) has improved medical care in SBS, decreasing mortality and improving the overall prognosis. However, the long-term use of PN is associated with the incidence of many complications, including liver disease and catheter-associated malfunction and bloodstream infections (CRBSIs). This manuscript is a narrative review of the current available evidence on the management of SBS in the pediatric population, focusing on prognostic factors and outcome. The literature review showed that in recent years, the standardization of management has demonstrated to improve the quality of life in these complex patients. Moreover, the development of knowledge in clinical practice has led to a reduction in mortality and morbidity. Diagnostic and therapeutic decisions should be made by a multidisciplinary team that includes neonatologists, pediatric surgeons, gastroenterologists, pediatricians, nutritionists and nurses. A significant improvement in prognosis can occur through the careful monitoring of nutritional status, avoiding dependence on PN and favoring an early introduction of enteral nutrition, and through the prevention, diagnosis and aggressive treatment of CRSBIs and SIBO. Multicenter initiatives, such as research consortium or data registries, are mandatory in order to personalize the management of these patients, improve their quality of life and reduce the cost of care.

Nutritional Management of Intestinal Failure due to Short Bowel Syndrome in Children

BACKGROUND

The most common cause of intestinal failure (IF) in childhood remains short bowel syndrome (SBS), where bowel mass is significantly reduced due to a congenital atresia or resection and parenteral nutrition (PN) needed. Home PN has improved outcome and quality of life, but the long-term therapeutic goal is to achieve enteral autonomy whilst avoiding long term complications. This paper is aimed at discussing nutritional strategies available to clinicians caring for these patients.

METHODS

A literature search was performed from 1992 to 2022 using Pubmed, MEDLINE and Cochrane Database of Systematic Reviews, and recent guidelines were reviewed. In the absence of evidence, recommendations reflect the authors' expert opinion.

RESULTS

Consensus on the best possible way of feeding children with IF-SBS is lacking and practice varies widely between centres. Feeding should commence as soon as possible following surgery. Oral feeding is the preferred route and breast milk (BM) the first milk of choice in infants. Donor BM, standard preterm or term formula are alternatives in the absence of maternal BM. Extensively hydrolysed or amino acid-based feeds are used when these are not tolerated. Solids should be introduced as soon as clinically appropriate. Children are encouraged to eat by mouth and experience different tastes and textures to avoid oral aversion. Aggressive weaning of PN and tube (over-) feeding are now discouraged.

CONCLUSIONS

To date, uniform agreement on the optimal type of feed, timing of food introduction and feeding regime used is lacking and great difference in practice remains. There is need for more research to establish common treatment protocols.

Growth hormone alters gross anatomy and morphology of the small and large intestines in age- and sex-dependent manners

PURPOSE

Growth hormone (GH) has an important role in intestinal barrier function, and abnormalities in GH action have been associated with intestinal complications. Yet, the impact of altered GH on intestinal gross anatomy and morphology remains unclear.

METHODS

This study investigated the influence of GH signaling on gross anatomy, morphology, and fibrosis by characterizing the small and large intestines in male and female bovine growth hormone transgenic (bGH) mice and GH receptor gene-disrupted (GHR-/-) mice at multiple timepoints.

RESULTS

The length, weight, and circumference of the small and large intestines were increased in bGH mice and decreased in GHR-/- mice across all ages. Colon circumference was significantly increased in bGH mice in a sex-dependent manner while significantly decreased in male GHR-/- mice. Villus height, crypt depth, and muscle thickness of the small intestine were generally increased in bGH mice and decreased in GHR-/- mice compared to controls with age- and sex-dependent exceptions. Colonic crypt depth and muscle thickness in bGH and GHR-/- mice were significantly altered in an age- and sex-dependent manner. Fibrosis was increased in the small intestine of bGH males at 4 months of age, but no significant differences were seen between genotypes at other timepoints.

CONCLUSION

This study observed notable opposing findings in the intestinal phenotype between mouse lines with GH action positively associated with intestinal gross anatomy (i.e. length, weight, and circumference). Moreover, GH action appears to alter morphology of the small and large intestines in an age- and sex-dependent manner.

Potential Benefits of Bovine Colostrum in Pediatric Nutrition and Health

Bovine colostrum (BC), the first milk produced from cows after parturition, is increasingly used as a nutritional supplement to promote gut function and health in other species, including humans. The high levels of whey and casein proteins, immunoglobulins (Igs), and other milk bioactives in BC are adapted to meet the needs of newborn calves. However, BC supplementation may improve health outcomes across other species, especially when immune and gut functions are immature in early life. We provide a review of BC composition and its effects in infants and children in health and selected diseases (diarrhea, infection, growth-failure, preterm birth, necrotizing enterocolitis (NEC), short-bowel syndrome, and mucositis). Human trials and animal studies (mainly in piglets) are reviewed to assess the scientific evidence of whether BC is a safe and effective antimicrobial and immunomodulatory nutritional supplement that reduces clinical complications related to preterm birth, infections, and gut disorders. Studies in infants and animals suggest that BC should be supplemented at an optimal age, time, and level to be both safe and effective. Exclusive BC feeding is not recommended for infants because of nutritional imbalances relative to human milk. On the other hand, adverse effects, including allergies and intolerance, appear unlikely when BC is provided as a supplement within normal nutrition guidelines for infants and children. Larger clinical trials in infant populations are needed to provide more evidence of health benefits when patients are supplemented with BC in addition to human milk or formula. Igs and other bioactive factors in BC may work in synergy, making it critical to preserve bioactivity with gentle processing and pasteurization methods. BC has the potential to become a safe and effective nutritional supplement for several pediatric subpopulations.

Colostrum Therapy for Human Gastrointestinal Health and Disease

There is increasing awareness that a broad range of gastrointestinal diseases, and some systemic diseases, are characterized by failure of the mucosal barrier. Bovine colostrum is a complex biological fluid replete with growth factors, nutrients, hormones, and paracrine factors which have a range of properties likely to contribute to mucosal healing in a wide range of infective, inflammatory, and injury conditions. In this review, we describe the anatomy and physiology of the intestinal barrier and how it may fail. We survey selected diseases in which disordered barrier function contributes to disease pathogenesis or progression, and review the evidence for or against efficacy of bovine colostrum in management. These disorders include enteropathy due to non-steroidal anti-inflammatory drugs (NSAIDs), inflammatory bowel disease (IBD), necrotizing enterocolitis, infectious diarrhea, intestinal failure, and damage due to cancer therapy. In animal models, bovine colostrum benefits NSAID enteropathy, IBD, and intestinal failure. In human trials, there is substantial evidence of efficacy of bovine colostrum in inflammatory bowel disease and in infectious diarrhea. Given the robust scientific rationale for using bovine colostrum as a promoter of mucosal healing, further work is needed to define its role in therapy.

Crosstalk between the growth hormone/insulin-like growth factor-1 axis and the gut microbiome: A new frontier for microbial endocrinology

Both the GH/IGF-1 axis and the gut microbiota independently play an important role in host growth, metabolism, and intestinal homeostasis. Inversely, abnormalities in GH action and microbial dysbiosis (or a lack of diversity) in the gut have been implicated in restricted growth, metabolic disorders (such as chronic undernutrition, anorexia nervosa, obesity, and diabetes), and intestinal dysfunction (such as pediatric Crohn's disease, colonic polyps, and colon cancer). Over the last decade, studies have demonstrated that the microbial impact on growth may be mediated through the GH/IGF-1 axis, pointing toward a potential relationship between GH and the gut microbiota. This review covers current research on the GH/IGF-1 axis and the gut microbiome and its influence on overall host growth, metabolism, and intestinal health, proposing a bidirectional relationship between GH and the gut microbiome.

Translational Advances in Pediatric Nutrition and Gastroenterology: New Insights from Pig Models

Pigs are increasingly important animals for modeling human pediatric nutrition and gastroenterology and complementing mechanistic studies in rodents. The comparative advantages in size and physiology of the neonatal pig have led to new translational and clinically relevant models of important diseases of the gastrointestinal tract and liver in premature infants. Studies in pigs have established the essential roles of prematurity, microbial colonization, and enteral nutrition in the pathogenesis of necrotizing enterocolitis. Studies in neonatal pigs have demonstrated the intestinal trophic effects of akey gut hormone, glucagon-like peptide 2 (GLP-2), and its role in the intestinal adaptation process and efficacy in the treatment of short bowel syndrome. Further, pigs have been instrumental in elucidating the physiology of parenteral nutrition-associated liver disease and the means by which phytosterols, fibroblast growth factor 19, and a new generation of lipid emulsions may modify disease. The premature pig will continue to be a valuable model in the development of optimal infant diets (donor human milk, colostrum), specific milk bioactives (arginine, growth factors), gut microbiota modifiers (pre-, pro-, and antibiotics), pharmaceutical drugs (GLP-2 analogs, FXR agonists), and novel diagnostic tools (near-infrared spectroscopy) to prevent and treat these pediatric diseases.

Growth Hormone Deficiency and Excess Alter the Gut Microbiome in Adult Male Mice

The gut microbiome has been implicated in host metabolism, endocrinology, and pathophysiology. Furthermore, several studies have shown that gut bacteria impact host growth, partially mediated through the growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis. Yet, no study to date has examined the specific role of GH on the gut microbiome. Our study thus characterized the adult gut microbial profile and intestinal phenotype in GH gene-disrupted (GH-/-) mice (a model of GH deficiency) and bovine GH transgenic (bGH) mice (a model of chronic, excess GH action) at 6 months of age. Both the GH-/- and bGH mice had altered microbial signatures, in opposing directions at the phylum and genus levels. For example, GH-/- mice had significantly reduced abundance in the Proteobacteria, Campylobacterota, and Actinobacteria phyla, whereas bGH mice exhibited a trending increase in those phyla compared with respective controls. Analysis of maturity of the microbial community demonstrated that lack of GH results in a significantly more immature microbiome while excess GH increases microbial maturity. Several common bacterial genera were shared, although in opposing directions, between the 2 mouse lines (e.g., decreased in GH-/- mice and increased in bGH mice), suggesting an association with GH. Similarly, metabolic pathways like acetate, butyrate, heme B, and folate biosynthesis were predicted to be impacted by GH. This study is the first to characterize the gut microbiome in mouse lines with altered GH action and indicates that GH may play a role in the growth of certain microbiota thus impacting microbial maturation and metabolic function.

Nutritional Feeding Strategies in Pediatric Intestinal Failure

Intestinal failure is defined as a critical reduction of the gut mass or function, below the minimum needed to absorb nutrients and fluids. The ultimate goal in intestinal failure is to promote bowel adaptation and reach enteral autonomy while a healthy growth and development is maintained. The condition is heterogeneous and complex. Therefore, recommendations for the type and duration of parenteral, enteral, and oral nutrition are variable, with the child's age as an additional key factor. The aim of this review is to provide an overview of nutritional feeding strategies in this heterogeneous population. Different perspectives on nutritional management, nutrition and adaptation, and microbiome and nutrition will be discussed.

Short Bowel Syndrome

Purpose of Review

Short gut syndrome is life-altering and life-threatening disease resulting most often from massive small bowel resection. Recent advances in understanding of the perturbed physiology in these patients have translated into improved care and outcomes. This paper seeks to review the advances of care in SBS patients.

Recent Findings

Anatomic considerations still predominate the early care of SBS patients, including aggressive preservation of bowel and documentation of remnant bowel length and quality. Intestinal adaptation is the process by which remnant bowel changes to fit the physiologic needs of the patient. Grossly, the bowel dilates and elongates to increase intestinal weight and protein content. Architectural changes are noted, such as villus lengthening and deepening of crypts. In addition, gene expression changes occur that function to maximize nutrient uptake and fluid preservation. Management is aimed at understanding these physiologic changes and augmenting them whenever possible in an effort to gain enteral autonomy. Complication mitigation is key, including avoidance of catheter complications, bloodstream infections, cholestasis, and nutrient deficiencies.

Summary

Multidisciplinary teams working together towards intestinal rehabilitation have shown improved outcomes. Today's practioner needs a current understanding of the ever-evolving care of these patients in order to promote enteral autonomy, recognize complications, and counsel patients and families appropriately.

Minimal Enteral Nutrition to Improve Adaptation After Intestinal Resection in Piglets and Infants

BACKGROUND

Minimal enteral nutrition (MEN) may induce a diet-dependent stimulation of gut adaptation following intestinal resection. Bovine colostrum is rich in growth factors, and we hypothesized that MEN with colostrum would stimulate intestinal adaptation, compared with formula, and would be well tolerated in patients with short bowel syndrome.

METHODS

In experiment 1, 3-day-old piglets with 50% distal small intestinal resection were fed parenteral nutrition (PN, n = 10) or PN plus MEN given as either colostrum (PN-COL, n = 5) or formula (PN-FORM, n = 9) for 7 days. Intestinal nutrient absorption and histomorphometry were performed. In experiment 2, tolerance and feasibility of colostrum supplementation were tested in a pilot study on 5 infants who had undergone intestinal resection, and they were compared with 5 resected infants who served as controls.

RESULTS

In experiment 1, relative wet-weight absorption and intestinal villus height were higher in PN-COL vs PN (53% vs 23% and 362 ± 13 vs 329 ± 7 µm, P < .05). Crypt depth and tissue protein synthesis were higher in PN-COL (233 ± 7 µm, 22%/d) and PN-FORM (262 ± 13 µm, 22%/d) vs PN (190 ± 4 µm, 9%/d, both P < .05). In experiment 2, enteral colostrum supplementation was well tolerated, and no infants developed clinical signs of cow's milk allergy.

CONCLUSION

Minimal enteral nutrition feeding with bovine colostrum and formula induced similar intestinal adaptation after resection in piglets. Colostrum was well tolerated by newly resected infants, but the clinical indication for colostrum supplementation to infants subjected to intestinal resection remains to be determined.

Prolonged Absence of Mechanoluminal Stimulation in Human Intestine Alters the Transcriptome and Intestinal Stem Cell Niche

BACKGROUND & AIMS

For patients with short-bowel syndrome, intestinal adaptation is required to achieve enteral independence. Although adaptation has been studied extensively in animal models, little is known about this process in human intestine. We hypothesized that analysis of matched specimens with and without luminal flow could identify new potential therapeutic pathways.

METHODS

Fifteen paired human ileum samples were collected from children aged 2-20 months during ileostomy-reversal surgery after short-segment intestinal resection and diversion. The segment exposed to enteral feeding was denoted as fed, and the diverted segment was labeled as unfed. Morphometrics and cell differentiation were compared histologically. RNA Sequencing and Gene Ontology Enrichment Analysis identified over-represented and under-represented pathways. Immunofluorescence staining and Western blot evaluated proteins of interest. Paired data were compared with 1-tailed Wilcoxon rank-sum tests with a P value less than .05 considered significant.

RESULTS

Unfed ileum contained shorter villi, shallower crypts, and fewer Paneth cells. Genes up-regulated by the absence of mechanoluminal stimulation were involved in digestion, metabolism, and transport. Messenger RNA expression of LGR5 was significantly higher in unfed intestine, accompanied by increased levels of phosphorylated signal transducer and activator of transcription 3 protein, and CCND1 and C-MYC messenger RNA. However, decreased proliferation and fewer LGR5+, OLFM4+, and SOX9+ intestinal stem cells (ISCs) were observed in unfed ileum.

CONCLUSIONS

Even with sufficient systemic caloric intake, human ileum responds to the chronic absence of mechanoluminal stimulation by up-regulating brush-border enzymes, transporters, structural genes, and ISC genes LGR5 and ASCL2. These data suggest that unfed intestine is primed to replenish the ISC population upon re-introduction of enteral feeding. Therefore, the elucidation of pathways involved in these processes may provide therapeutic targets for patients with intestinal failure. RNA sequencing data are available at Gene Expression Omnibus series GSE82147.

Effects of a Breast Milk Diet on Enteral Feeding Outcomes of Neonates with Gastrointestinal Disorders

OBJECTIVE

The objective of this study was to assess whether a diet of ≥50% breast milk (BM) was associated with earlier transition off parenteral nutrition (PN) in neonates with gastrointestinal (GI) disorders.

METHODS

This retrospective study assessed enteral feeding outcomes of neonates with surgical GI disorders admitted within the first week of life to a single center between January 1, 2012 and August 10, 2015. Outcomes were assessed according to diet from the point of first enteral intake through 7 days of full enteral feeds. Diets were classified as 100%, ≥50%, or <50% BM.

RESULTS

One hundred sixty-three patients with an average gestational age of 36 weeks (range 28-40) and birthweight of 2570 g (range 1250-4900) were included. Significant differences in days to full enteral feeds between the 100% and <50% BM groups were found (median 21 versus 32 days; p = 0.023). There were no significant differences between the 100% and ≥50% BM (p = 0.05) or ≥50% versus <50% BM groups (p = 0.74). The 100% BM group had significantly fewer days on PN compared to the ≥50% BM group (median 21 versus 28.5 days, p = 0.034). Hospital length of stay was significantly shorter in the 100% BM group, which was discharged an average of 10 and 13.5 days sooner than the ≥50% and <50% BM groups (p < 0.05).

CONCLUSIONS

Neonates with specific GI disorders who received a 100% BM diet were found to achieve earlier full enteral feeds, have shorter PN courses, and be discharged from the hospital significantly sooner than those who received diets that included formula.

Promoting intestinal adaptation by nutrition and medication

The ultimate goal in the treatment of short bowel syndrome is to wean patients off parenteral nutrition, by promoting intestinal adaptation. Intestinal adaptation is the natural compensatory process that occurs after small bowel resection. Stimulating the remaining bowel with enteral nutrition can enhance this process. Additionally, medication can be used to either reduce factors that complicate the adaptation process or to stimulate intestinal adaptation, such as antisecretory drugs and several growth factors. The aim of this review was to provide an overview of the best nutritional strategies and medication that best promote intestinal adaptation.

Porcine models of digestive disease: the future of large animal translational research

There is increasing interest in nonrodent translational models for the study of human disease. The pig, in particular, serves as a useful animal model for the study of pathophysiological conditions relevant to the human intestine. This review assesses currently used porcine models of gastrointestinal physiology and disease and provides a rationale for the use of these models for future translational studies. The pig has proven its utility for the study of fundamental disease conditions such as ischemia-reperfusion injury, stress-induced intestinal dysfunction, and short bowel syndrome. Pigs have also shown great promise for the study of intestinal barrier function, surgical tissue manipulation and intervention, as well as biomaterial implantation and tissue transplantation. Advantages of pig models highlighted by these studies include the physiological similarity to human intestine and mechanisms of human disease. Emerging future directions for porcine models of human disease include the fields of transgenics and stem cell biology, with exciting implications for regenerative medicine.

Changes in the colon microbiota and intestinal cytokine gene expression following minimal intestinal surgery

AIM: To investigate the impact of minor abdominal surgery on the caecal microbial population and on markers of gut inflammation.

METHODS: Four week old piglets were randomly allocated to a no-surgery “control” group (n = 6) or a “transection surgery” group (n = 5). During the transection surgery procedure, a conventional midline incision of the lower abdominal wall was made and the small intestine was transected at a site 225 cm proximal to the ileocaecal valve, a 2 cm segment was removed and the intestine was re-anastomosed. Piglets received a polymeric infant formula diet throughout the study period and were sacrificed at two weeks post-surgery. Clinical outcomes including weight, stool consistency and presence of stool fat globules were monitored. High throughput DNA sequencing of colonic content was used to detect surgery-related disturbances in microbial composition at phylum, family and genus level. Diversity and richness estimates were calculated for the control and minor surgery groups. As disturbances in the gut microbial community are linked to inflammation we compared the gene expression of key inflammatory cytokines (TNF, IL1B, IL18, IL12, IL8, IL6 and IL10) in ileum, terminal ileum and colon mucosal extracts obtained from control and abdominal surgery groups at two weeks post-surgery.

RESULTS: Changes in the relative abundance of bacterial species at family and genus level were confined to bacterial members of the Proteobacteria and Bacteroidetes phyla. Family level compositional shifts included a reduction in the relative abundance of Enterobacteriaceae (22.95 ± 5.27 vs 2.07 ± 0.72, P < 0.01), Bacteroidaceae (2.54 ± 0.56 vs 0.86 ± 0.43, P < 0.05) and Rhodospirillaceae (0.40 ± 0.14 vs 0.00 ± 0.00, P < 0.05) following transection surgery. Similarly, at the genus level, changes associated with transection surgery were restricted to members of the Proteobacteria and Bacteroidetes phyla and included decreased relative abundance of Enterobacteriaceae (29.20 ± 6.74 vs 2.88 ± 1.08, P < 0.01), Alistipes (4.82 ± 1.73 vs 0.18 ± 0.13, P < 0.05) and Thalassospira (0.53 ± 0.19 vs 0.00 ± 0.00, P < 0.05). Surgery-associated microbial dysbiosis was accompanied by increased gene expression of markers of inflammation. Within the ileum IL6 expression was decreased (4.46 ± 1.60 vs 0.24 ± 0.06, P < 0.05) following transection surgery. In the terminal ileum, gene expression of TNF was decreased (1.51 ± 0.13 vs 0.80 ± 0.16, P < 0.01) and IL18 (1.21 ± 0.18 vs 2.13 ± 0.24, P < 0.01), IL12 (1.04 ± 0.16 vs 1.82 ± 0.32, P < 0.05) and IL10 (1.04 ± 0.06 vs 1.43 ± 0.09, P < 0.01) gene expression increased following transection surgery. Within the colon, IL12 (0.72 ± 0.13 vs 1.78 ± 0.28, P < 0.01) and IL10 (0.98 ± 0.02 vs 1.95 ± 0.14, P < 0.01) gene expression were increased following transection surgery.

CONCLUSION: This study suggests that minor abdominal surgery in infants, results in long-term alteration of the colonic microbial composition and persistent gastrointestinal inflammation.

Animal models of gastrointestinal and liver diseases. Animal models of infant short bowel syndrome: translational relevance and challenges

Intestinal failure (IF), due to short bowel syndrome (SBS), results from surgical resection of a major portion of the intestine, leading to reduced nutrient absorption and need for parenteral nutrition (PN). The incidence is highest in infants and relates to preterm birth, necrotizing enterocolitis, atresia, gastroschisis, volvulus, and aganglionosis. Patient outcomes have improved, but there is a need to develop new therapies for SBS and to understand intestinal adaptation after different diseases, resection types, and nutritional and pharmacological interventions. Animal studies are needed to carefully evaluate the cellular mechanisms, safety, and translational relevance of new procedures. Distal intestinal resection, without a functioning colon, results in the most severe complications and adaptation may depend on the age at resection (preterm, term, young, adult). Clinically relevant therapies have recently been suggested from studies in preterm and term PN-dependent SBS piglets, with or without a functional colon. Studies in rats and mice have specifically addressed the fundamental physiological processes underlying adaptation at the cellular level, such as regulation of mucosal proliferation, apoptosis, transport, and digestive enzyme expression, and easily allow exogenous or genetic manipulation of growth factors and their receptors (e.g., glucagon-like peptide 2, growth hormone, insulin-like growth factor 1, epidermal growth factor, keratinocyte growth factor). The greater size of rats, and especially young pigs, is an advantage for testing surgical procedures and nutritional interventions (e.g., PN, milk diets, long-/short-chain lipids, pre- and probiotics). Conversely, newborn pigs (preterm or term) and weanling rats provide better insights into the developmental aspects of treatment for SBS in infants owing to their immature intestines. The review shows that a balance among practical, economical, experimental, and ethical constraints will determine the choice of SBS model for each clinical or basic research question.

Emerging Piglet Models of Neonatal Short Bowel Syndrome

Short bowel syndrome (SBS) is a growing problem in the human neonatal population. In infants, SBS is the leading cause of intestinal failure, the state of being unable to absorb sufficient nutrients for growth and development. Neonates with SBS are dependent on long-term parenteral nutrition therapy, but many succumb to the complications of sepsis and liver disease. Research in neonatal SBS is challenged by the ethical limits of studying sick human neonates and the heterogeneous nature of the disease process. Outcomes in SBS vary depending on residual intestinal anatomy, intestinal length, patient age, and exposure to nutrition therapies. The neonatal piglet serves as an appropriate translational model of the human neonate because of similarities in gastrointestinal ontogeny, physiological maturity, and adaptive processes. Re-creating the disease process in a piglet model presents a unique opportunity for researchers to discover novel insights and therapies in SBS. Emerging piglet models of neonatal SBS now represent the entire spectrum of disease seen in human infants. This review aims to contextualize these emerging piglet models within the context of SBS as a heterogeneous disease. We first explore the factors that account for SBS heterogeneity and then explore the suitability of the neonatal piglet as an appropriate translational animal model. We then examine differences between the emerging piglet models of neonatal SBS and how these differences affect their translational potential to human neonates with SBS.

Short bowel syndrome in infants: the critical role of luminal nutrients in a management program

Short bowel syndrome develops when the remnant mass of functioning enterocytes following massive resections cannot support growth or maintain fluid–electrolyte balance and requires parenteral nutrition. Resection itself stimulates the intestine’s inherent ability to adapt morphologically and functionally. The capacity to change is very much related to the high turnover rate of enterocytes and is mediated by several signals; these signals are mediated in large part by enteral nutrition. Early initiation of enteral feeding, close clinical monitoring, and ongoing assessment of intestinal adaptation are key to the prevention of irreversible intestinal failure. The length of the functional small bowel remnant is the most important variable affecting outcome. The major objective of intestinal rehabilitation programs is to achieve early oral nutritional autonomy while maintaining normal growth and nutrition status and minimizing total parenteral nutrition related comorbidities such as chronic progressive liver disease. Remarkable progress has been made in terms of survivability and quality of life, especially in the context of coordinated multidisciplinary programs, but much work remains to be done.

Prematurity Reduces Functional Adaptation to Intestinal Resection in Piglets

BACKGROUND

Necrotizing enterocolitis and congenital gastrointestinal malformations in infants often require intestinal resection, with a subsequent risk of short bowel syndrome (SBS). We hypothesized that immediate intestinal adaptation following resection of the distal intestine with placement of a jejunostomy differs between preterm and term neonates.

METHODS

Preterm or term piglets were born by cesarean section and fed enterally for 2 days. On day 2, piglets were subjected to 50% distal intestinal resection with placement of a jejunostomy. On the following 4-5 days, piglets received parenteral nutrition with gradually increasing doses of enteral nutrition (bovine colostrum). Intestinal tissue samples were collected at delivery and 2 and 6-7 days after birth for histological examination and assessment of digestive enzyme activities.

RESULTS

Preterm and term piglets showed similar increases in intestinal weight and digestive enzyme activities from birth to 2 days. On days 6-7 after birth, the remnant intestine showed a similar density (g/cm) and mucosal mass in term and preterm piglets, but villus height, crypt depth, enzyme activities (sucrase, maltase, dipeptidyl peptidase IV [DPPIV]), and hexose uptake capacity were significantly higher in term piglets (P < .05). Preterm piglets were more prone to develop hypoglycemia, respiratory distress syndrome, dehydration, and circulatory instability after surgery compared with term piglets.

CONCLUSION

Studies on intestinal adaptation after resection are feasible in both preterm and term piglets, but intensive clinical support is required when rearing preterm piglets with SBS. Physiological instability and immaturity of the intestine may explain the fact that immediate adaptation after resection is reduced in preterm vs term neonates.

Cell lineage identification and stem cell culture in a porcine model for the study of intestinal epithelial regeneration

Significant advances in intestinal stem cell biology have been made in murine models; however, anatomical and physiological differences between mice and humans limit mice as a translational model for stem cell based research. The pig has been an effective translational model, and represents a candidate species to study intestinal epithelial stem cell (IESC) driven regeneration. The lack of validated reagents and epithelial culture methods is an obstacle to investigating IESC driven regeneration in a pig model. In this study, antibodies against Epithelial Adhesion Molecule 1 (EpCAM) and Villin marked cells of epithelial origin. Antibodies against Proliferative Cell Nuclear Antigen (PCNA), Minichromosome Maintenance Complex 2 (MCM2), Bromodeoxyuridine (BrdU) and phosphorylated Histone H3 (pH3) distinguished proliferating cells at various stages of the cell cycle. SOX9, localized to the stem/progenitor cells zone, while HOPX was restricted to the +4/‘reserve’ stem cell zone. Immunostaining also identified major differentiated lineages. Goblet cells were identified by Mucin 2 (MUC2); enteroendocrine cells by Chromogranin A (CGA), Gastrin and Somatostatin; and absorptive enterocytes by carbonic anhydrase II (CAII) and sucrase isomaltase (SIM). Transmission electron microscopy demonstrated morphologic and sub-cellular characteristics of stem cell and differentiated intestinal epithelial cell types. Quantitative PCR gene expression analysis enabled identification of stem/progenitor cells, post mitotic cell lineages, and important growth and differentiation pathways. Additionally, a method for long-term culture of porcine crypts was developed. Biomarker characterization and development of IESC culture in the porcine model represents a foundation for translational studies of IESC-driven regeneration of the intestinal epithelium in physiology and disease.

Bovine colostrum to children with short bowel syndrome: a randomized, double-blind, crossover pilot study

BACKGROUND

Management of short bowel syndrome (SBS) aims to achieve intestinal autonomy to prevent fluid, electrolyte, and nutrient deficiencies and maintain adequate development. Remnant intestinal adaptation is required to obtain autonomy. In the newborn pig, colostrum has been shown to support intestinal development and hence adaptive processes.

AIM

The efficacy of bovine colostrum to improve intestinal function in children with SBS was evaluated by metabolic balance studies.

MATERIALS AND METHODS

Nine children with SBS were included in a randomized, double-blind, crossover study. Twenty percent of enteral fluid intake was replaced with bovine colostrum or a mixed milk diet for 4 weeks, separated by a 4-week washout period. Intestinal absorption of energy and wet weight was used to assess intestinal function and the efficacy of colostrum.

RESULTS

Colostrum did not improve energy or wet weight absorption compared with the mixed milk diet (P = 1.00 and P = .93, respectively). Growth as measured by weight and knemometry did not differ between diets (P = .93 and P = .28). In these patients, <150% enteral energy absorption of basal metabolic rate and 50% enteral fluid absorption of basal fluid requirement suggested intestinal failure and a need for parenteral nutrition (PN).

CONCLUSION

Inclusion of bovine colostrum to the diet did not improve intestinal function. Metabolic nutrient and wet weight balance studies successfully assessed intestinal function, and this method may distinguish between intestinal insufficiency (non-PN-dependent) and intestinal failure (PN-dependent) patients.

Randomised controlled trial of colostrum to improve intestinal function in patients with short bowel syndrome

BACKGROUND/OBJECTIVES

Colostrum is rich in immunoregulatory, antimicrobial and trophic components supporting intestinal development and function in newborns. We assessed whether bovine colostrum could enhance intestinal adaptation and function in adult short bowel syndrome (SBS) patients.

SUBJECTS/METHODS

Twelve SBS patients in this randomised cross-over study received 4 weeks oral supplement of bovine colostrum or an iso-energetic and iso-proteinaceous control (2.4 MJ/d, 500 ml/day) separated by a 4-week washout period. Patients were admitted four times for 72-h periods of fluid, electrolyte and nutrient balance studies. Meals, faeces and urine were weighed, and energy, macronutrient and electrolyte contents were analysed to calculate net nutrient uptake. Body composition was measured by dual-energy X-ray absorptiometry scans, and functional tests of handgrip strength and lung functions were performed. Eight patients completed the study and were included in the analysis.

RESULTS

Both supplements (colostrum and control) not only increased protein (0.96 ± 0.42 MJ/d, P=0.004 1.03 ± 0.44 MJ/d, P=0.003) and energy (1.46 ± 1.02 MJ/d, P=0.005, 1.76 ± 1.46 MJ/d, P=0.01) absorption but also absolute faecal wet weight excretions (231 ± 248 g/d, P=0.002, 319 ± 299 g/d, P=0.03), compared with baseline measurements. Both supplements improved handgrip strength (P=0.03) while only the control supplement increased lean body mass (1.12 ± 1.33 kg, P<0.049). Colostrum was not found to be superior to the control.

CONCLUSION

Intake of high-protein milk supplements increased net nutrient absorption for adult SBS patients, but at the expense of increased diarrhoea. Despite high contents of bioactive factors, colostrum did not significantly improve intestinal absorption, body composition or functional tests compared with the control.

Enteral feeding induces early intestinal adaptation in a parenterally fed neonatal piglet model of short bowel syndrome

BACKGROUND

Successful small intestinal (SI) adaptation following surgical resection is essential for optimizing newborn growth and development, but the potential for adaptation is unknown. The authors developed an SI resection model in neonatal piglets supported by intravenous and enteral nutrition.

METHODS

Piglets (n = 33, 12-13 days old) were randomized to 80% SI resection with parenteral nutrition feeding (R-PN), 80% SI resection with PN + enteral feeding (R-EN), or sham SI transection with PN + enteral feeding (sham-EN). In resected pigs, the distal 100 cm of ileum (residual SI) and 30 cm of proximal SI were left intact. All pigs received parenteral nutrition postsurgery. Enteral nutrition piglets received continuous gastric infusion of elemental diet from day 3 (40:60 parenteral nutrition:enteral nutrition). Piglets were killed 4, 6, or 10 days postsurgery.

RESULTS

By 10 days, R-EN piglets had longer residual SI than R-PN and sham-EN pigs (P < .05). At days 6 and 10, R-EN piglets had greater weight per length of intact SI (P < .05) and isolated mucosa (P < .05) compared to other groups. Greater gut weight in R-EN piglets was facilitated by a greater cellular proliferation index (P < .01) by 4 days compared to other groups and greater overall ornithine decarboxylase activity vs R-PN piglets (P < .05).

CONCLUSIONS

This new model demonstrated profound SI adaptation, initiated early postsurgery by polyamine synthesis and crypt cell proliferation and only in response to enteral feeding. These changes translated to greater gut mass and length within days, likely improving functional capacity long term.

Morphological and functional changes in the colon after massive small bowel resection

PURPOSE

Anecdotal evidence suggests that the colon plays an important role after small bowel resection (SBR). However, colonic changes have not previously been studied. The aim of this study was to characterize morphological and functional changes within the colon after SBR and elucidate the influence of diet complexity on adaptation.

METHOD

In study 1, 4-week-old piglets underwent a 75% SBR or sham operation and were studied at 2, 4, and 6 weeks postoperation to allow analysis of early and late adaptation responses. Piglets received a polymeric infant formula (PIF). In study 2, SBR piglets received an elemental diet and were studied at 6 weeks postoperation and compared with SBR + PIF piglets from study 1. For both studies, immunohistochemistry was used to quantitate intestinal cell types. Changes in functional proteins were measured by Western blot, enteroendocrine/peptide YY (PYY), enterocyte/liver fatty acid binding protein (L-FABP), and goblet cells/trefoil factor 3 (TFF3).

RESULTS

In study 1, early and late adaptation-related changes were observed after SBR. Early adaptation included increased numbers of enterocytes (P = .0001), whereas late adaptation included increased proliferative cell numbers (P = .02). Enteroendocrine, goblet, and apoptotic cells numbers were significantly elevated in the resected group at all time-points studied (P < .05). Functional changes included increased levels of L-FABP (P = .04) and PYY (P = .03). There was no change in TFF3 expression. In study 2, feeding with an elemental diet resulted in suboptimal adaptation as evidenced by reduced rate of weight gain and significant reductions in total cell numbers (P = .0001), proliferative (P = .0001) and apoptotic cells (P = .04), enteroendocrine cells (P = .001), and PYY expression (P .004).

CONCLUSION

These findings indicate that significant morphological and functional changes occur in the colon after massive SBR and that these occur as early and late adaptation responses. Elemental diet was associated with suboptimal adaptation suggesting an effect of diet complexity on colonic adaptation.

Proteomic analysis of the intestinal adaptation response reveals altered expression of fatty acid binding proteins following massive small bowel resection

Intestinal adaptation in response to the loss of the small intestine is essential to restore enteral autonomy in patients who have undergone massive small bowel resection (MSBR). In a proportion of patients, intestinal function is not restored, resulting in chronic intestinal failure (IF). Early referral of such patients for transplant provides the best prognosis; however, the molecular mechanisms underlying intestinal adaptation remain elusive and there is currently no convenient marker to predict whether patients will develop IF. We have investigated the adaptation response in a well-characterized porcine model of intestinal adaptation. 2D DIGE analysis of ileal epithelium from piglets recovering from massive small bowel resection (MSBR) identified over 60 proteins that changed specifically in MSBR animals relative to nonoperational or sham-operated controls. Three fatty acid binding proteins (L-FABP, FABP-6, and I-FABP) showed changes in MSBR animals. The expression changes and localization of each FABP were validated by immunoblotting and immunohistochemical analysis. FABP expression changes in MSBR animals occurred concurrently with altered triglyceride and bile acid metabolism as well as weight gain. The observed FABP expression changes in the ileal epithelium occur as part of the intestinal adaptation response and could provide a clinically useful marker to evaluate adaptation following MSBR.