Isolation and characterization of intestinal stem cells based on surface marker combinations and colony-formation assay.

BACKGROUND & AIMS: Identification of intestinal stem cells (ISCs) has relied heavily on the use of transgenic reporters in mice, but this approach is limited by mosaic expression patterns and difficult to directly apply to human tissues. We sought to identify reliable surface markers of ISCs and establish a robust functional assay to characterize ISCs from mouse and human tissues. METHODS: We used immunohistochemistry, real-time reverse-transcription polymerase chain reaction, and fluorescence-activated cell sorting (FACS) to analyze intestinal epithelial cells isolated from mouse and human intestinal tissues. We compared different combinations of surface markers among ISCs isolated based on expression of Lgr5-green fluorescent protein. We developed a culture protocol to facilitate the identification of functional ISCs from mice and then tested the assay with human intestinal crypts and putative ISCs. RESULTS: CD44(+)CD24(lo)CD166(+) cells, isolated by FACS from mouse small intestine and colon, expressed high levels of stem cell-associated genes. Transit-amplifying cells and progenitor cells were then excluded based on expression of GRP78 or c-Kit. CD44(+)CD24(lo)CD166(+) GRP78(lo/-) putative stem cells from mouse small intestine included Lgr5-GFP(hi) and Lgr5-GFP(med/lo) cells. Incubation of these cells with the GSK inhibitor CHIR99021 and the E-cadherin stabilizer Thiazovivin resulted in colony formation by 25% to 30% of single-sorted ISCs. CONCLUSIONS: We developed a culture protocol to identify putative ISCs from mouse and human tissues based on cell surface markers. CD44(+)CD24(lo)CD166(+), GRP78(lo/-), and c-Kit(-) facilitated identification of putative stem cells from the mouse small intestine and colon, respectively. CD44(+)CD24(-/lo)CD166(+) also identified putative human ISCs. These findings will facilitate functional studies of mouse and human ISCs.

Brief report: CD24 and CD44 mark human intestinal epithelial cell populations with characteristics of active and facultative stem cells.

Recent seminal studies have rapidly advanced the understanding of intestinal epithelial stem cell (IESC) biology in murine models. However, the lack of techniques suitable for isolation and subsequent downstream analysis of IESCs from human tissue has hindered the application of these findings toward the development of novel diagnostics and therapies with direct clinical relevance. This study demonstrates that the cluster of differentiation genes CD24 and CD44 are differentially expressed across LGR5 positive "active" stem cells as well as HOPX positive "facultative" stem cells. Fluorescence-activated cell sorting enables differential enrichment of LGR5 (CD24-/CD44+) and HOPX (CD24+/CD44+) cells for gene expression analysis and culture. These findings provide the fundamental methodology and basic cell surface signature necessary for isolating and studying intestinal stem cell populations in human physiology and disease.

Outcomes From Colonic Pull-Through for Cloacal Exstrophy Differ by Colon Length: A Multi-Institutional Study.

BACKGROUND: Cloacal exstrophy (CE) represents a rare sub-group of anorectal malformations. Traditionally managed with a permanent colostomy, colonic pull-through (PT) has emerged to allow cleanliness without a life-long stoma. We sought to understand outcomes of PT in a large multi-center CE population. METHODS: We performed a retrospective study involving eleven pediatric hospitals. We gathered data on demographics, outcomes, and anatomical factors including colon length. Continuous variables were analyzed with Wilcoxon rank-sum tests and categorial variables with Fisher's exact tests. RESULTS: There were 98 patients, of which the majority (n = 70, 71.4 %) never underwent PT. There were no differences in exstrophy type, demographics, or associated anomalies. Median age at PT was 1.3 years (IQR 0.3-3.7). Of the cohort that continue to use their PT, the majority (n = 16, 69.6 %) are not clean. In total, 7.1 % (n = 7) of the cohort is clean with a PT, and only one patient is continent. Clean patients have a longer colon length than those who are not clean or opt for re-do ostomy (64.0 cm [IQR 46.0-82.0] vs 26.5 cm [IQR 11.6-41.2], p = 0.005). CONCLUSION: Overall, we demonstrate that most children born with CE will keep their stoma. Only a small percentage who elect to undergo colonic PT are clean for stool. Greater colon length correlates with success. This suggests that multiple factors, including colon length, are important when considering PT in a child with CE. LEVEL OF EVIDENCE: III.

Does Delayed Diagnosis of Hirschsprung Disease Impact Post-operative and Functional Outcomes? A Multi-Center Review From the Pediatric Colorectal and Pelvic Learning Consortium.

BACKGROUND: Hirschsprung Disease (HD) is a rare cause of functional bowel obstruction in children. Patients are typically diagnosed in the neonatal period and undergo pull-through (PT) soon after diagnosis. The optimal management and post-operative outcomes of children who present in a delayed fashion are unknown. METHODS: A multi-center retrospective review of children with HD was performed at participating Pediatric Colorectal and Pelvic Learning Consortium sites. Children were stratified by age at diagnosis (neonates <29 days; infants 29 days-12 months; toddler 1 year-5 years and child >5 years). RESULTS: 679 patients with HD from 14 sites were included; Most (69%) were diagnosed in the neonatal period. Age at diagnosis was not associated with differences in 30-day complication rates or need for PT revision. Older age at diagnosis was associated with a greater likelihood of undergoing fecal diversion after PT (neonate 10%, infant 12%, toddler 26%, child 28%, P < 0.001) and a greater need for intervention for constipation or incontinence postoperatively (neonate 56%, infant 62%, toddler 78%, child 69%, P < 0.001). CONCLUSION: Delayed diagnosis of HD does not impact 30-day post-operative outcomes or need for revision surgery but, delayed diagnosis is associated with increased need for fecal diversion after pull-through. LEVEL OF EVIDENCE: III.

Can Anorectal Stenosis be Managed With Dilations Alone? A PCPLC Review.

PURPOSE: Congenital anorectal stenosis is managed by dilations or operative repair. Recent studies now propose use of dilations as the primary treatment modality to potentially defer or eliminate the need for surgical repair. We aim to characterize the management and outcomes of these patients via a multi-institutional review using the Pediatric Colorectal and Pelvic Learning Consortium (PCPLC) registry. METHODS: A retrospective database review was performed using the PCPLC registry. The patients were evaluated for demographics, co-morbidities, diagnostic work-up, surgical intervention, current bowel management, and complications. RESULTS: 64 patients with anal or rectal stenosis were identified (57 anal, 7 rectal) from a total of 14 hospital centers. 59.6% (anal) and 42.9% (rectal) were male. The median age was 3.2 (anal) and 1.9 years (rectal). 11 patients with anal stenosis also had Currarino Syndrome with 10 of the 11 patients diagnosed with a presacral mass compared to only one rectal stenosis with Currarino Syndrome and a presacral mass. 13 patients (22.8%, anal) and one (14.3%, rectal) underwent surgical correction. Nine patients (8 anal, 1 rectal) underwent PSARP. Other procedures performed were cutback anoplasty and anterior anorectoplasty. The median age at repair was 8.4 months (anal) and 10 days old (rectal). One patient had a wound complication in the anal stenosis group. Bowel management at last visit showed little differences between groups or treatment approach. CONCLUSION: The PCPLC registry demonstrated that these patients can often be managed successfully with dilations alone. PSARP is the most common surgical repair chosen for those who undergo surgical repair. LEVEL OF EVIDENCE: III.

Variation in Practice Surrounding Antegrade Colonic Enema Channel Placement.

PURPOSE: Antegrade colonic enemas (ACE) can be an effective management option for defecation disorders and improve quality of life. Best practice regarding channel placement is unclear and variation may exist around preferred initial type of channel, age at placement, and underlying diagnoses. We aimed to describe practice patterns and patient characteristics around ACE channel placement. METHODS: We conducted a multicenter retrospective study of children with an ACE channel cared for at sites participating in the Pediatric Colorectal and Pelvic Learning Consortium (PCPLC) from 2017 to 2022. Kruskal-Wallis test was utilized to test the age at surgery by site with significance level of 0.05. RESULTS: 500 patients with ACE channel were included. 293 (58.6%) patients had their ACE procedure at a PCPLC center. The median age at surgery was 7.6 [IQR 5.3-11.0] years for the overall cohort and 8.1 [IQR 5.3-11.5] years for placement at PCPLC centers. For PCPLC centers, median age at placement varied significantly across centers (p = 0.009). 371 (74.2%) patients received Malone appendicostomy, 116 (23.2%) received cecostomy, and 13 (2.6%) received Neo-Malone appendicostomy. Median age of patients by channel type was 7.7 [IQR 5.3-11.0], 7.5 [IQR 5.7-11.0], and 9.8 [IQR 4.2-11.6] years, respectively. The most common indication for cecostomy was idiopathic/refractory constipation (52.6%), whereas anorectal malformation was the most common indication for Malone (47.2%) and Neo-Malone (61.5%). Among ACE channels placed at PCPLC centers, there was variation across institutions in preferred initial channel type. The 4 highest volume centers favored Malone appendicostomy over cecostomy. CONCLUSION: There is variation in practice of ACE channel placement. At specialty pediatric colorectal centers, age at time of placement and type of channel placed varied across institutions. Further work is needed to better characterize diagnosis- and age-focused patient centered outcomes to clarify recommendations for our patients who benefit from these procedures. TYPE OF STUDY: Retrospective comparative study. LEVEL OF EVIDENCE: Level III.

Intestinal stem cells remain viable after prolonged tissue storage.

Intestinal stem cells (ISCs) are responsible for renewal of the epithelium both during normal homeostasis and following injury. As such, they have significant therapeutic potential. However, whether ISCs can survive tissue storage is unknown. We hypothesize that, although the majority of epithelial cells might die, ISCs would remain viable for at least 24 h at 4 °C. To explore this hypothesis, jejuna of C57Bl6/J or Lgr5-LacZ mice were removed and either processed immediately or placed in phosphate-buffered saline at 4 °C. Delayed isolation of epithelium was performed after 24, 30, or 48 h storage. At the light microscope level, despite extensive apoptosis of villus epithelial cells, small intestinal crypts remained morphologically intact for 30 h and ISCs were identifiable via Lgr5-LacZ positivity. Electron microscopy showed that ISCs retained high integrity for 24 h. When assessed by flow cytometry, ISCs were more resistant to degeneration than the rest of the epithelium, including neighboring Paneth cells, with higher viability across all time points. Cultured isolated crypts showed no loss of capacity to form complex enteroids after 24 h tissue storage, with efficiencies after 7 days of culture remaining above 80 %. By 30 h storage, efficiencies declined but budding capability was retained. We conclude that, with delay in isolation, ISCs remain viable and retain their proliferative capacity. In contrast, the remainder of the epithelium, including the Paneth cells, exhibits degeneration and programmed cell death. If these findings are recapitulated in human tissue, storage at 4 °C might offer a valuable temporal window for the harvesting of crypts or ISCs for therapeutic application.

Rectal Prolapse Following Repair of Anorectal Malformation: Incidence, Risk Factors, and Management.

BACKGROUND: The incidence and optimal management of rectal prolapse following repair of an anorectal malformation (ARM) has not been well-defined. METHODS: A retrospective cohort study was performed utilizing data from the Pediatric Colorectal and Pelvic Learning Consortium registry. All children with a history of ARM repair were included. Our primary outcome was rectal prolapse. Secondary outcomes included operative management of prolapse and anoplasty stricture following operative management of prolapse. Univariate analyses were performed to identify patient factors associated with our primary and secondary outcomes. A multivariable logistic regression was developed to assess the association between laparoscopic ARM repair and rectal prolapse. RESULTS: A total of 1140 patients met inclusion criteria; 163 (14.3%) developed rectal prolapse. On univariate analysis, prolapse was significantly associated with male sex, sacral abnormalities, ARM type, ARM complexity, and laparoscopic ARM repairs (p < 0.001). ARM types with the highest rates of prolapse included rectourethral-prostatic fistula (29.2%), rectovesical/bladder neck fistula (28.8%), and cloaca (25.0%). Of those who developed prolapse, 110 (67.5%) underwent operative management. Anoplasty strictures developed in 27 (24.5%) patients after prolapse repair. After controlling for ARM type and hospital, laparoscopic ARM repair was not significantly associated with prolapse (adjusted odds ratio (95% CI): 1.50 (0.84, 2.66), p = 0.17). CONCLUSION: Rectal prolapse develops in a significant subset of patients following ARM repair. Risk factors for prolapse include male sex, complex ARM type, and sacral abnormalities. Further research investigating the indications for operative management of prolapse and operative techniques for prolapse repair are needed to define optimal treatment. TYPE OF STUDY: Retrospective cohort study. LEVEL OF EVIDENCE: II.

Intestinal crypts reproducibly expand in culture.

BACKGROUND: In vitro growth techniques for intestinal crypts and single intestinal stem cells have been recently described, but several questions of translational importance remain unaddressed. The purpose of this study was to first, evaluate if intestinal crypts reproducibly expand in vitro; second, determine the impact of age and region of intestine on crypt growth in vitro; and third, determine the effects of cryopreservation on crypt growth in vitro. METHODS AND MATERIALS: Crypts were harvested from 5 cm of proximal, middle, and distal small intestine of C57BL/6J mice aged 4 wk, 6-8 wk, 12-14 wk, and 18-20 wk (n = 4-6 animals) and cultured. For each region, we determined the efficiency of crypts forming enterospheres (day 1) and progressing to enteroids (day 7). Subsequently, enteroids were passaged and cryopreserved to determine if growth was changed by these manipulations. RESULTS: Forty-three to 99% of intestinal crypts formed enterospheres, with higher efficiency in proximal small intestine and in younger mice. Twenty-five to 64% of enterospheres progressed to budding enteroids within 7 d. In vitro expansion was greater in proximal enteroids. This expansion continued in a logarithmic fashion, with ≈ 97% replating efficiency of isolated enteroid crypt buds. Following cryopreservation, ≈ 90% of enteroids recovered normal proliferative capacity. CONCLUSIONS: Intestinal crypt culture is efficient and significantly expands intestinal tissue in a reproducible manner. Regional and age growth differences may reflect distinct stem cell characteristics or differences in support cells. The ability to culture and expand intestinal tissue in vitro provides a potential translational approach toward understanding and treating patients with short bowel syndrome.

Recurrent Gastrointestinal Bleed Due to Small Bowel Vascular Malformation in a Patient with Turner Syndrome Diagnosed with Surgically Assisted Push Enteroscopy.

BACKGROUND Obscure gastrointestinal bleeding accounts for approximately 5% of all cases of gastrointestinal bleeding and the most frequent site is the small bowel. Turner syndrome (TS) is a genetic disorder of the second X chromosome in females. The association between gastrointestinal vascular malformations and Turner syndrome has been described in some case reports. Vascular malformation in Turner's syndrome can vary from asymptomatic to severe recurrent GI bleeds, but data on diagnosis and management of these patients are lacking. CASE REPORT A 14-year-old girl with TS presented with recurrent symptomatic melena. The initial work-up included a negative upper endoscopy, negative bidirectional endoscopies, and a video capsule endoscopy (VCE) that demonstrated large amount of blood and small erythematous lesion in the small bowel without active bleeding, and a negative Meckel scan. CT angiography was remarkable for prominent left lower mesenteric blood vessels, and a single-balloon enteroscopy demonstrated prominent vasculature throughout the small bowel. A a clip was placed at the site of a questionable bleed. The patient underwent a surgically assisted push enteroscopy due to recurrent bleeding; findings were consistent with diffuse vascular malformations. She was started on tranexamic acid and later transitioned to estrogen therapy without further reports of GI bleeding, anemia, or adverse effects from treatment 6 months after initial presentation. CONCLUSIONS Small bowel bleeding can be life-threating, and evidence-based guidelines in children are needed. Turner syndrome is associated with gastrointestinal vascular malformations, and suspicion for this diagnosis should be high for these patients when presenting with gastrointestinal bleeding. Estrogen might be an effective therapy in TS adolescent patients in the setting of diffuse vascular malformations (DVM).

Presacral mature cystic teratoma associated with Currarino syndrome in an adolescent with androgen insensitivity: illustrative case.

BACKGROUND: Currarino syndrome is a rare disorder that classically presents with the triad of presacral mass, anorectal malformation, and spinal dysraphism. The presacral mass is typically benign, although malignant transformation is possible. Surgical treatment of the mass and exploration and repair of associated dysraphism are indicated for diagnosis and symptom relief. There are no previous reports of Currarino syndrome in an androgen-insensitive patient. OBSERVATIONS: A 17-year-old female patient presented with lack of menarche. Physical examination and laboratory investigation identified complete androgen insensitivity. Imaging analysis revealed a presacral mass lesion, and the patient was taken to surgery for resection of the mass and spinal cord untethering. Intraoperative ultrasound revealed a fibrous stalk connecting the thecal sac to the presacral mass, which was disconnected without the need for intrathecal exploration. The presacral mass was then resected, and pathological analysis revealed a mature cystic teratoma. Postoperatively, the patient recovered without neurological or gastrointestinal sequelae. LESSONS: Diagnosis of incomplete Currarino syndrome may be difficult but can be identified via work-up of other disorders, such as androgen insensitivity. Intraoperative ultrasound is useful for surgical decision making and may obviate the need for intrathecal exploration during repair of dysraphism in the setting of Currarino syndrome.

The presence of a neurodiverse disorder is associated with increased use of antegrade enema therapy in children with severe constipation: A study from the Pediatric Colorectal and Pelvic Learning Consortium (PCPLC).

INTRODUCTION: Children with severe constipation and a neurodiverse disorder (Autism and/or developmental delay) represent a challenging bowel management group. Treatment outcomes with laxative or enema therapy remain limited and are often complicated by patient/caregiver compliance. We hypothesized that children with neurodiverse disorders and severe constipation would benefit from a bowel management program (BMP) that includes early use of antegrade enemas. MATERIALS AND METHODS: Children requiring BMP in the Pediatric Colorectal and Pelvic Learning Consortium (PCPLC) registry with diagnosis of constipation and/or constipation with pseudo-incontinence were reviewed. Those with Hirschsprung disease and/or Anorectal Malformation were excluded. BMP needs in patients with a neurodiverse diagnosis were compared to those without to evaluate differences in BMP's. RESULTS: 372 patients requiring a BMP were identified. 95 patients (58 autism spectrum, 54 developmental delay) were neurodiverse, and 277 patients were not. Neurodiverse patients had a higher prevalence of enema therapy 62.1% (59/95) vs. 54.9% (152/273) and use of antegrade enema therapy 33.7% (32/95) vs. 21.2% (58/273), p = 0.126. Neurodiverse patients were older 37.9% (36/95) > 12 years vs. 23.1% (63/273), p = 0.001 and 47.6% (10/21) were changed from laxative to enema therapy over time. 80% (8/10) of those changed from laxatives to enemas used antegrade therapy. 67.3% (35/52) of neurodiverse patients followed over time were on enema therapy at the most recent visit with 80% (28/35) requiring antegrade therapy. CONCLUSION: A large portion of patients with a neurodiverse disorder who fail laxative therapy use antegrade enemas to achieve effective bowel management. Early consideration of an antegrade conduit may simplify treatment in this group of children. LEVEL OF EVIDENCE: III.

Adjuncts to bowel management for fecal incontinence and constipation, the role of surgery; appendicostomy, cecostomy, neoappendicostomy, and colonic resection.

Constipation and fecal incontinence are common problems in children after repair of an anorectal malformation (ARM). While many children can be effectively managed with an oral laxative regimen, others require a mechanical colonic washout to achieve social continence. Appendicostomy and cecostomy are two techniques which permit antegrade access to the colon for the purpose of enema delivery, which improves compliance and quality of life for patients and families. The purpose of this article is to review, using a case-based approach, the indications for placement of a channel for antegrade enema access, clinical scenarios in which one technique would be preferred over another, common complications following each procedure.

Measure twice and cut once: Comparing endoscopy and 3D cloacagram for the common channel and urethral measurements in patients with cloacal malformations.

INTRODUCTION: Precise and accurate measurement of the common channel and urethra is a critical determinant prior to the repair of cloacal malformations. Endoscopy and 3D reconstruction cloacagram are two common modalities utilized to help plan the surgical approach, however the consistency between these methods is unknown. METHODS: Common channel and urethral lengths obtained by endoscopy and 3D cloacagram of cloaca patients at six pediatric colorectal centers were compared. Data are given as mean (range). RESULTS: 72 patients were included in the study. Common channel measurements determined by 3D cloacagram and endoscopy were equal in 7 cases (10%). Endoscopic measurements of the common channel were longer than 3D cloacagram in 20 (28%) cases and shorter in the remaining 44 (62%) cases. The absolute difference between measurements of the common channel was 7.2 mm (0-2.4 cm). Urethral measurements by both modalities were equal in 8 cases (12%). Endoscopic measurement of the urethra was longer than that by 3D cloacagram in 20 (31%) patients and shorter in 37 (57%) of cases. The absolute difference between measurements of the urethra was 5.1 mm (0-2.0 cm). The reconstruction (e.g. TUM or urogenital separation) that would be performed according to measurements determined by 3D cloacagram and endoscopic measurements differed in 13/62 (21%) patients with each structure identified and common channel measurements of >1 cm. CONCLUSION: Significant variation exists in the measurements of the common channel and urethra in patients with cloacal malformations as determined by endoscopy and 3D cloacagram. This variation should be considered as these measurements influence the decision to perform either a TUM or urogenital separation. Based on these findings, 3D cloacagram should be performed in all patients prior to cloaca repair to prevent mischaracterization of the malformation. LEVEL OF EVIDENCE: Level IV.

Pediatric Inflammatory Bowel Disease: Special Considerations.

Pediatric inflammatory bowel disease may present differently than adult onset disease. It is important to consider a broader differential diagnosis in very early onset disease. Diagnostic and treatment decisions must consider the long term risks and benefits over a lifetime. Surgical triggers in children may include impaired growth and inability to wean from steroids in addition to standard adult indications. Effective transition of care to adult providers is a key to prevent flares and loss of follow-up.

Thoracic empyema, application of video-assisted thoracic surgery and its current management.

PURPOSE OF REVIEW: Pneumonia in children is frequently complicated by pleural effusions, which rarely progress to empyema. Appropriate clinical management depends on correctly diagnosing the stage of the disease process. Recently, increasing use of video-assisted thoracic debridement has altered the traditional management of pleural effusions and empyema in children, resulting in decreasing reliance on thoracentesis and earlier surgical intervention. RECENT FINDINGS: We review the current literature supporting the clinical indications for video-assisted thoracic debridement compared with traditional management, including the use of thoracentesis, chest tube placement, fibrinolytic therapy and open thoracotomy in children with empyema. Recent studies support the early application of video-assisted thoracic debridement in children with empyema compared with traditional therapy, as it decreases the number of procedures and studies performed and the duration of chest tube drainage and is associated with less pain and shorter recovery period than open thoracotomy. SUMMARY: We propose a clinical algorithm supporting the early use of video-assisted thoracic debridement in the management of empyema in children.