Major surgical conditions of childhood and their lifelong implications: comprehensive review.

BACKGROUND: In recent decades, the survival of children with congenital anomalies and paediatric cancer has improved dramatically such that there has been a steady shift towards understanding their lifelong health outcomes. Paediatric surgeons will actively manage such conditions in childhood and adolescence, however, adult surgeons must later care for these 'grown-ups' in adulthood. This article aims to highlight some of those rare disorders encountered by paediatric surgeons requiring long-term follow-up, their management in childhood and their survivorship impact, in order that the adult specialist may be better equipped with skills and knowledge to manage these patients into adulthood. METHODS: A comprehensive literature review was performed to identify relevant publications. Research studies, review articles and guidelines were sought, focusing on the paediatric management and long-term outcomes of surgical conditions of childhood. The article has been written for adult surgeon readership. RESULTS: This article describes the aforementioned conditions, their management in childhood and their lifelong implications, including: oesophageal atresia, tracheo-oesophageal fistula, malrotation, short bowel syndrome, duodenal atresia, gastroschisis, exomphalos, choledochal malformations, biliary atresia, Hirschsprung disease, anorectal malformations, congenital diaphragmatic hernia, congenital lung lesions and paediatric cancer. CONCLUSION: The increasing survivorship of children affected by surgical conditions will translate into a growing population of adults with lifelong conditions and specialist healthcare needs. The importance of transition from childhood to adulthood is becoming realized. It is hoped that this timely review will enthuse the readership to offer care for such vulnerable patients, and to collaborate with paediatric surgeons in providing successful and seamless transitional care.

Ernica Clinical Consensus Statements on Total Colonic and Intestinal Aganglionosis.

BACKGROUND: Hirschsprung disease is a congenital intestinal motility disorder characterized by an absence of enteric ganglion cells. Total colonic aganglionosis and near total or total intestinal aganglionosis, defined as absence of ganglion cells in the entire colon and with variable length of small bowel involved, are life-threatening conditions which affect less than 10 % of all patients with Hirschsprung disease. The aim of this project was to develop clinical consensus statements within ERNICA, the European Reference Network for rare congenital digestive diseases, on four major topics: Surgical treatment of total colonic aganglionosis, surgical treatment of total intestinal aganglionosis, management of poor bowel function in total colonic and/or intestinal aganglionosis and long-term management in total colonic and or intestinal aganglionosis. METHODS: A multidisciplinary panel of representatives from ERNICA centers was invited to participate. Literature was searched, using specified search terms, in Medline (ALL), Embase and Google Scholar. Abstracts were screened and full text publications were selected. The panel was divided in four groups that extracted data from the full text publications and suggested draft statements for each of the major topics. A modified Delphi process was used to refine and agree on the statements. RESULTS: The consensus statement was conducted by a multidisciplinary panel of 24 participants from 10 European countries, 45 statements reached consensus after 3 Delphi-rounds. The availability of high-quality clinical evidence was limited, and most statements were based on expert opinion. Another 25 statements did not reach consensus. CONCLUSIONS: Total colonic and total intestinal aganglionosis are rare variants of Hirschsprung disease, with very limited availability of high-quality clinical evidence. This consensus statement provides statements on the surgical treatment, management of poor bowel function and long-term management for these rare patients. The expert panel agreed that patients benefit from multidisciplinary and personalized care, preferably in an expert center. TYPE OF STUDY: Clinical consensus statement. LEVEL OF EVIDENCE: 3a.

A Retrospective Study of Long-Term Outcomes in 16 ABO-Incompatible Deceased Donor Pediatric Liver Transplants from a National Transplant Center at Helsinki University Hospital, Finland, 1987-2022.

BACKGROUND The use of ABO-incompatible liver transplants (ABO-ILTs) from deceased donors has become more common due to the shortage of available donor livers and increased transplant waiting times. This retrospective study from a national transplant center at Helsinki University Hospital, Finland, aimed to assess the long-term outcomes of ABO-incompatible deceased donor pediatric liver transplants between 1987 and 2022. MATERIAL AND METHODS Sixteen (9.5%) of the 169 pediatric liver transplantations were ABO-ILTs. The median age at transplantation was 5.0 (0.5-15.4) years. Reasons for ABO-ILTs were acute liver failure (18.75%), malignancy (12.5%), small body size and long waiting time (25%), and other reasons (43.75%). The median post-transplant follow-up time was 147 (0.72-353) months. Patient and graft survival and occurrence of surgical complications were compared to ABO-identical transplants, and anti-ABO antibody titers were analyzed. RESULTS The 1-, 3-, and 5-year patient survivals were comparable between the ABO-I and ABO-compatible groups, being 81.3%, 73.9%, and 73.9% (ABO-I) and 87.5%, 82.5%, 77.9% (ABO-compatible), respectively. Three patients with ABO-ILTs died of sepsis and multiorgan failure during the first 3 months after transplantation. The occurrence of biliary complications and early vascular thrombosis (<30 days after transplantation) did not differ significantly between recipients with an ABO-ILT vs ABO-compatible liver graft. CONCLUSIONS The findings from this study support findings from previous studies that outcomes after ABO-incompatible liver transplants in children were comparable to outcomes from ABO-identical liver transplants.

Hirschsprung disease.

Hirschsprung disease (HSCR) is a rare congenital intestinal disease that occurs in 1 in 5,000 live births. HSCR is characterized by the absence of ganglion cells in the myenteric and submucosal plexuses of the intestine. Most patients present during the neonatal period with the first meconium passage delayed beyond 24 h, abdominal distension and vomiting. Syndromes associated with HSCR include trisomy 21, Mowat-Wilson syndrome, congenital central hypoventilation syndrome, Shah-Waardenburg syndrome and cartilage-hair hypoplasia. Multiple putative genes are involved in familial and isolated HSCR, of which the most common are the RET proto-oncogene and EDNRB. Diagnosis consists of visualization of a transition zone on contrast enema and confirmation via rectal biopsy. HSCR is typically managed by surgical removal of the aganglionic bowel and reconstruction of the intestinal tract by connecting the normally innervated bowel down to the anus while preserving normal sphincter function. Several procedures, namely Swenson, Soave and Duhamel procedures, can be undertaken and may include a laparoscopically assisted approach. Short-term and long-term comorbidities include persistent obstructive symptoms, enterocolitis and soiling. Continued research and innovation to better understand disease mechanisms holds promise for developing novel techniques for diagnosis and therapy, and improving outcomes in patients.

Cutoffs and Characteristics of Abnormal Bowel Dilatation in Pediatric Short Bowel Syndrome.

OBJECTIVES: Although excessive intestinal dilatation associates with worsened outcomes in pediatric short bowel syndrome (SBS), little is known about the natural history and definition of pathological dilatation. We addressed fore-, mid-, and hind-gut dilatation in children with SBS, who had not undergone autologous intestinal reconstructive (AIR) surgery, in relation to controls. METHODS: SBS children without history of AIR surgery (n = 59) and age-matched controls without any disclosed intestinal pathology (n = 140) were included. Maximum diameter of duodenum, small bowel (SB), and colon were measured in each intestinal contrast series during 2002 to 2020 and expressed as diameter ratio (DR) to L5 vertebrae height. Predictive ability of DR for weaning off parenteral nutrition (PN) was analyzed with Cox proportional hazards regression models using multiple cutoffs. RESULTS: Duodenum (DDR), SB (SBDR), and colon (CDR) DR were 53%, 183%, and 23% higher in SBS patients compared to controls ( P < 0.01 for all). The maximal DDR and SBDR measured during follow-up is associated with current PN dependence and young age. DDR correlated with SBDR ( r = 0.586, P < 0.01). Patients with maximal DDR less than 1.5, which was also the 99th percentile for controls, were 2.5-fold more likely to wean off PN ( P = 0.005), whereas SBDR and CDR were not predictive for PN duration. CONCLUSIONS: All segments of remaining bowel, especially SB, dilate above normal levels in children with SBS. In SBS children without AIR surgery, PN dependence and young age is associated with duodenal and small intestinal dilatation, while duodenal dilatation also predicted prolonged PN.

Bacterial translocation markers and toll-like receptors in biliary atresia following successful portoenterostomy.

AIM: The gut-liver axis may contribute to pathophysiology of cholestatic liver disorders like biliary atresia (BA) by bacterial translocation (BT). Toll-like receptors (TLR) are pattern recognition receptors known to activate innate immunity and secretion of inflammatory cytokines. Herein, we examined BT-associated biomarkers and TLRs in relation to liver injury after successful portoenterostomy (SPE) in BA. METHODS: Serum levels of lipopolysaccharide-binding protein (LBP), CD14, LAL, TNF-α, IL-6 and FABP2 along with liver expression of TLRs (TLR1, TLR4, TLR7 and TLR9), LBP and CD14 were measured during median 4.9 (1.7-10.6) years follow-up after SPE in 45 BA patients. RESULTS: Serum LBP, CD14, TNF-α and IL-6 all increased after SPE whereas LAL and FABP-2 remained unchanged. Serum LBP correlated positively with CD14 and markers of hepatocyte injury and cholestasis, but not with Metavir fibrosis stage, transcriptional markers for fibrosis (ACTA2) or ductular reaction. Serum CD14 concentration was significantly higher in patients with portal hypertension than without. While liver expression of TLR4 and LBP remained low, TLR7 and TLR1 showed marked BA-specific increases, and TLR7 correlated with Metavir fibrosis stage and ACTA2. CONCLUSION: BT does not seem to play a significant role in liver injury after SPE in our series of BA patients.

Efficacy and Safety of Teduglutide in Infants and Children With Short Bowel Syndrome Dependent on Parenteral Support.

OBJECTIVES: Our objective was to evaluate the short- and long-term safety and efficacy of teduglutide treatment in infants and children with short bowel syndrome with intestinal failure (SBS-IF). METHODS: Two open-label phase 3 studies and 1 extension study investigated the short- and long-term safety and efficacy of teduglutide (0.05 mg/kg/day) in infants and children with SBS-IF: NCT03571516, 24-week study of infants who were randomized to receive teduglutide or standard of care (SoC); NCT02980666, 24-week study of infants and children who all received teduglutide; and NCT03268811, 24-week extension study of patients who completed NCT02980666 (patients could receive up to 48 weeks of total treatment). RESULTS: Twelve infants and 8 children enrolled in the core studies, and 2 infants and 7 children in the extension study. After 24 weeks of treatment, parenteral support (PS) requirements reduced by ≥20% from baseline for 4 infants (57.1%) and 4 children (66.7%) receiving teduglutide and for 2 infants receiving SoC (50.0%). One infant (50.0%) and 4 children (80.0%) receiving teduglutide maintained the ≥20% reduction in PS at 48 weeks of treatment. Two children receiving teduglutide achieved enteral autonomy, after 12 weeks and 28 weeks of treatment, respectively. All adverse events (AEs) were in line with known impacts of SBS-IF and adverse reactions to teduglutide. Only one serious AE (abdominal pain) was considered related to teduglutide. CONCLUSIONS: Short- and long-term treatment with teduglutide resulted in clinically meaningful reductions in PS requirements for infants and children with SBS-IF. Teduglutide was well tolerated, and efficacy improved with longer-term treatment.

Characteristics, management and outcomes of choledochal malformations in Finnish adult patients.

CONCLUSIONS: Nearly half of operated patients developed long-term postoperative complications. A novel association between CMs and IBD was observed. Although no hepatobiliary malignancies regardless of treatment modality were encountered, the number of patients and length of follow-up remained limited.

Long-Term Outcomes After Autologous Intestinal Reconstructive Surgery in Children With Short Bowel Syndrome.

OBJECTIVES: Autologous intestinal reconstructive (AIR) surgery is frequently utilized in the management of pediatric short bowel syndrome (SBS). However, little is known about the long-term sequela of these procedures. METHODS: We undertook a retrospective follow-up study addressing parenteral nutrition (PN) dependence, nutritional status, intestinal morbidity, and related complications in SBS patients having undergone AIR surgery (SBS-AIR, n = 19). We compared results with conservatively treated control SBS patients (SBS-C, n = 45). Eligible patients were identified from our institutional intestinal failure registry during 1985-2019. RESULTS: After median 11.4 follow-up years, 42% of SBS-AIR patients received PN in relation to 36% in SBS-C group ( P = 0.6210), and overall PN duration was significantly longer (35.4 vs 10 months, P = 0.0004) in SBS-AIR group. Although symptoms of intestinal dysfunction improved in majority (62%) of patients after AIR surgery, their symptoms remained more frequent and severe at latest follow-up compared to SBS-C group (39% vs 5%, P = 0.0015). Although bacterial overgrowth was more frequent in SBS-AIR group (53% vs 24%, P = 0.0416), latest endoscopy findings and fecal calprotectin levels as well as occurrence of anastomotic/staple line ulcerations were comparable between groups. Histological liver steatosis (50% vs 18%, P = 0.042) and impaired bone health (26% vs 6.7%, P = 0.042) were more frequent in SBS-AIR patients. CONCLUSIONS: While AIR surgery improved gastrointestinal symptoms and transition to enteral autonomy in majority of patients, a noteworthy proportion of them continued to suffer from clinically significant intestinal dysfunction and related complications. Close long-term follow-up of pediatric AIR surgery patients is mandatory.

Bowel Control, Bladder Function, and Quality of Life in Children with Cloacal Malformations.

INTRODUCTION: Long-term outcomes of cloacal malformations remain unclear. We evaluated postoperative bowel control, bladder function and quality of life in patients under 18 years of age with cloaca. MATERIALS AND METHODS: This was a multi-center cross-sectional observational study accomplished by the Nordic Pediatric Surgery Research Consortium. Patients with a cloacal malformation, 4-17 years of age, were eligible. Data including patient characteristics, surgical procedures, and complications were retrieved from case records. Established questionnaires with normative control values evaluating bowel function, bladder function, and health-related quality of life (HRQoL) were sent to the patients and their caregivers. The study was approved by the participating center's Ethics Review Authorities. RESULTS: Twenty-six (67%) of 39 eligible patients with median age 9.5 (range, 4-17) years responded. Twenty-one (81%) patients had a common channel ≤3 cm. Imaging confirmed sacral anomalies in 11 patients and spinal cord abnormalities in nine. Excluding patients with stoma (n = 5), median bowel function score was 12 [7-19], and 5 patients (20%) reported a bowel function score ≥17, approaching normal bowel control level. Bowel management increased proportion of socially continent school-aged children to 52%. Six (23%) patients had a permanent urinary diversion or used clean intermittent catheterization (CIC), while majority (70%) of the remaining patients were urinary continent. The reported HRQoL was comparable to healthy Swedish children. CONCLUSION: Whilst well-preserved spontaneous bowel control was rare, a majority of patients were dry for urine without any additional procedures. Few patients experienced social problems or negative impact on HRQoL due to bladder or bowel dysfunction. LEVEL OF EVIDENCE: Level IV.

Histopathological liver steatosis linked with high parenteral glucose and amino acid supply in infants with short bowel syndrome.

BACKGROUND: Steatosis is a common feature of intestinal failure-associated liver disease (IFALD) in adult and older pediatric patients receiving long-term parenteral nutrition (PN). There are limited clinical data concerning steatosis in infants with short bowel syndrome (SBS). We investigated early histopathological steatosis and its association to PN. METHODS: In this retrospective study, 31 patients with SBS had a diagnostic liver biopsy taken at the median age of 5 (IQR 3-8) months. Follow-up biopsy was available for 24 patients at the median age of 29 (IQR 14-52) months. We evaluated the biopsies for steatosis and other histopathological signs of IFALD and compared results with patient characteristics, PN composition, and liver biochemistry. RESULTS: Diagnostic biopsies revealed steatosis in 8 (26%) patients. At the age of 3 months, patients with steatosis had received higher amounts of parenteral glucose: median 15.1 (IQR 12.4-17.2) vs 12.3 (8.7-14.4) g/kg/d (P = 0.04), amino acids: 2.9 (2.5-3.4) vs 2.2 (1.6-2.7) g/kg/d (P = 0.03), and energy: 87 (80-98) vs 73 (54-79) kcal/kg/d (P = 0.01) than those without steatosis. We detected no significant differences in parenteral lipid intake between the groups. Steatosis also associated with increased serum bile acid (P = 0.02), alanine aminotransferase (P = 0.0002), and aspartate aminotransferase (P = 0.001) levels. CONCLUSIONS: In this cohort, high parenteral glucose, amino acid, and energy provision associated with liver steatosis in infants with SBS. We recommend monitoring of bile acid and transaminase levels while aiming for PN with balanced macronutrient supply according to current recommendations to protect the liver from steatosis.

Distal Recurrent Tracheoesophageal Fistula after Repair of Esophageal Atresia-Incidence, Risk Factors, and Outcome.

OBJECTIVE: The aim of this study was to assess incidence, risk factors, and outcomes of distal recurrent tracheoesophageal fistula (RTEF) after repair of esophageal atresia (EA). METHODS: Ethical consent was obtained. Data collection was done by review of hospital records of 286 patients (268 in-house and 18 referred) who underwent repair of type C or D EA from 1980 to 2021. Spitz class, long-gap (tracheoesophageal fistula at carina), fundoplication, leakage, and stricture were assessed as RTEF risk factors. Outcome measures were long-term closure of RTEF, retainment of native esophagus, and survival. RESULTS: RTEF occurred in 23 patients (19 in-house) with type C (n = 22) or type D (n = 1) EA with median 4.4 (interquartile range [IQR]: 1.7-13) months after repair. Five patients had late RTEF 3.5 to 16 years after repair. Nineteen (7.3%) in-house patients developed RTEF. Presenting symptoms, age at diagnosis, and presence of anastomotic stricture (AS) are listed. No statistically significant risk factors were found, risk ratio of 0.5 to 2.7 (IQR: 0.1-8.7), p-value of 0.25 to 0.75. Detached closure clip and esophageal foreign body contributed to RTEF in two patients. Sixteen patients underwent rethoracotomy for closure of RTEF, 5 (22%) with AS eventually underwent esophageal reconstruction after a period with cervical esophagostomy. Two patients with late-manifested RTEFs underwent closure with laser cauterization. In 22 patients, treatment of RTEF succeeded, whereas 1 (4%) premature patient died of instant re-RTEF. CONCLUSION: RTEF had an incidence of 7% with diverse patterns of manifestation and predicting factors. Closure rate and patient survival were excellent, but RTEF with AS predicted loss of native esophagus.

A randomized, controlled multicenter feasibility pilot trial on imaging confirmed uncomplicated acute appendicitis: Appendectomy vs. symptomatic treatment in pediatric patients (the APPSYPP) trial study protocol.

INTRODUCTION: Imaging-confirmed uncomplicated acute appendicitis can be effectively and safely treated with antibiotics in most adults and children. Symptomatic treatment may have similar efficacy and safety. METHODS AND ANALYSIS: The APPSYPP trial is a randomized national multicenter feasibility superiority pilot study comparing appendectomy with symptomatic treatment in children with imaging-confirmed uncomplicated acute appendicitis. INCLUSION CRITERIA: 1) age ≥ 7 and < 16 years, 2) imaging-confirmed uncomplicated acute appendicitis and 3) CRP ≤ 65 mg/l. Patients are randomized to receive emergency laparoscopic appendectomy or symptomatic treatment. To ensure patient safety, symptomatically treated patients are hospitalized for at least 24 h receiving standard practice intravenous fluids and analgesics according to standard clinical practice. Primary outcome is 30-day treatment success defined by the absence of any treatment failure criteria. In appendectomy, treatment failure is defined as normal appendiceal histopathology or any postintervention complication requiring general anesthesia. In symptomatic treatment, treatment failure is defined as 1) inability for hospital discharge without appendectomy within 48 h after randomization with a finding of histopathologically inflamed appendix, 2) appendectomy during the initial hospital stay due to clinical progression of appendicitis with complicated acute appendicitis both histopathologically and surgically, 3) appendectomy with a histopathological finding of acute appendicitis after hospital discharge, or 4) any complication of appendicitis requiring general anesthesia. Detailed predefined secondary outcomes will be analyzed. ETHICS AND DISSEMINATION: Study was approved by Ethics Committee of Helsinki University Hospital (ID:HUS/1993/2021), conducted in compliance with the declaration of Helsinki with results disseminated in peer-reviewed scientific journals. TRIAL REGISTRATION: ClinicalTrials.gov (NCT05289713).

Infection Prevention and Management in Pediatric Short Bowel Syndrome.

Short bowel syndrome (SBS) is a rare disease with potentially life-threatening consequences. In addition to intestinal failure-associated liver disease, infections and other complications related to central venous catheters (CVCs) cause a significant burden to patients with SBS and may even necessitate an intestinal transplant eventually. The need for long-term central venous access and the intestinal dysfunction associated with SBS drive the need for intestinal failure-specific approach to prevent and treat infections in patients with SBS. In bacterial infections, the line can often be salvaged with proficient antibiotic therapy. Repeated catheter replacements are predisposed to recurrent infections and thrombotic complications, which may limit the long-term survival of patients with SBS. Protocol-based CVC access procedures and daily care including taurolidine and ethanol catheter locks have been shown to reduce infection rates substantially. Compromised intestinal function in SBS predisposes to small bowel bacterial overgrowth, mucosal injury, and increased permeability. These pathophysiological changes are concentrated in a subset of patients with excessive bowel dilatation and frequent bowel-derived infections. In such patients, reconstructive intestinal surgery may be indicated. Probiotics have not been effective in infection prevention in SBS and carry a significant risk of complications. While more studies focusing on the prevention of infections and their complications are needed, protocol-based approach and multidisciplinary teams in the care of patients with SBS have been shown to reduce complications and improve outcomes.

Liver secretin receptor predicts portoenterostomy outcomes and liver injury in biliary atresia.

Biliary atresia (BA) is a chronic neonatal cholangiopathy characterized by fibroinflammatory bile duct damage. Reliable biomarkers for predicting native liver survival (NLS) following portoenterostomy (PE) surgery are lacking. Herein we explore the utility of 22 preidentified profibrotic molecules closely connected to ductular reaction (DR) and prevailing after successful PE (SPE), in predicting PE outcomes and liver injury. We used qPCR and immunohistochemistry in a BA cohort including liver samples obtained at PE (n = 53) and during postoperative follow-up after SPE (n = 25). Of the 13 genes over-expressed in relation to cholestatic age-matched controls at PE, only secretin receptor (SCTR) expression predicted cumulative 5-year NLS and clearance of jaundice. Patients in the highest SCTR expression tertile showed 34-55% lower NLS than other groups at 1-5 years after PE (P = 0.006-0.04 for each year). SCTR expression was also significantly lower [42 (24-63) vs 75 (39-107) fold, P = 0.015] among those who normalized their serum bilirubin after PE. Liver SCTR expression localized in cholangiocytes and correlated positively with liver fibrosis, DR, and transcriptional markers of fibrosis (ACTA2) and cholangiocytes (KRT7, KRT19) both at PE and after SPE. SCTR is a promising prognostic marker for PE outcomes and associates with liver injury in BA.

Long-term outcomes of biliary atresia patients surviving with their native livers.

Portoenterostomy (PE) has remained as the generally accepted first line surgical treatment for biliary atresia (BA) for over 50 years. Currently, close to half of BA patients survive beyond 10 years with their native livers, and most of them reach adulthood without liver transplantation (LT). Despite normalization of serum bilirubin by PE, ductular reaction and portal fibrosis persist in the native liver. The chronic cholangiopathy progresses to cirrhosis, complications of portal hypertension, recurrent cholangitis or hepatobiliary tumors necessitating LT later in life. Other common related health problems include impaired bone health, neuromotor development and quality of life. Only few high-quality trials are available for evidence-based guidance of post-PE adjuvant medical therapy or management of the disease complications. Better understanding of the pathophysiological mechanisms connecting native liver injury to clinical outcomes is critical for development of accurate follow-up tools and novel therapies designed to improve native liver function and survival.

Intrinsic Cellular Susceptibility to Barrett's Esophagus in Adults Born with Esophageal Atresia.

The prevalence of Barrett's esophagus (BE) in adults born with esophageal atresia (EA) is four times higher than in the general population and presents at a younger age (34 vs. 60 years). This is (partly) a consequence of chronic gastroesophageal reflux. Given the overlap between genes and pathways involved in foregut and BE development, we hypothesized that EA patients have an intrinsic predisposition to develop BE. Transcriptomes of Esophageal biopsies of EA patients with BE (n = 19, EA/BE); EA patients without BE (n = 44, EA-only) and BE patients without EA (n = 10, BE-only) were compared by RNA expression profiling. Subsequently, we simulated a reflux episode by exposing fibroblasts of 3 EA patients and 3 controls to acidic conditions. Transcriptome responses were compared to the differential expressed transcripts in the biopsies. Predisposing single nucleotide polymorphisms, associated with BE, were slightly increased in EA/BE versus BE-only patients. RNA expression profiling and pathway enrichment analysis revealed differences in retinoic acid metabolism and downstream signaling pathways and inflammatory, stress response and oncological processes. There was a similar effect on retinoic acid signaling and immune response in EA patients upon acid exposure. These results indicate that epithelial tissue homeostasis in EA patients is more prone to acidic disturbances.