Glial-derived growth factor signaling pathway in infantile hypertrophic pyloric stenosis

Hypertrophic Pyloric Stenosis: 10 Years' Experience with Standard Open and Laparoscopic Approach

PURPOSE

Hypertrophic pyloric stenosis (HPS) is the most common cause of gastric obstruction in newborns. Extra-mucosal pyloromyotomy can be performed through a small laparotomy or laparoscopy. The aim of this study was to compare the two surgical techniques. We also analyzed the incidence of HPS in infants in the last 10 years in relation to the demographic trend of our province.

METHODS

We analyzed all the cases of HPS treated at our Unit between January 2010 and December 2019. The data were obtained from operating systems. Data about the demographic trends, in particular, the number of births and the population residing in the province of Verona from 2010 to 2019, were also retrieved.

RESULTS

During the study period, 60 patients were treated for HPS and met the inclusion criteria. Of these, 56 males and 4 females with an average age of 38±14 days at surgery were included. No differences were found in terms of the duration of surgery, post-operative complications, duration of hospitalization, and weight at the time of surgery. The only statistically significant data was the chlorine level in cases with and without post-operative vomiting (97±3.5 vs. 102±3.3 mmol/L, p<0.05). There was a lower incidence of HPS from 2014 to 2019; however, there was no significant evidence regarding the correlation between this and the reduced birth rate recorded in the province of Verona during the same period.

CONCLUSION

Although laparoscopic pyloromyotomy is a highly complex procedure, it is a feasible alternative to the classic open technique.

Does Maternal Omega 3 Supplementation Protect Against Infantile Hypertrophic Pyloric Stenosis?

OBJECTIVES

Infantile hypertrophic pyloric stenosis (IHPS) is potentially life threatening. The etiology of IHPS remains unknown and many risk factors have been reported. We aimed to assess the prevalence of known risk factors and investigate maternal nutrition and habits as possible additional risk factors for IHPS.

METHODS

This case-control study includes mothers of infants diagnosed with IHPS and control mothers of infants, age 2 to 11 months, hospitalized in the pediatric department due to other conditions. Cases of IHPS were identified by review of all infants diagnosed with IHPS and operated upon in 2010 to 2016 at 2 major hospitals in central Israel. Data regarding potential risk factors were collected via questionnaires in both study groups.

RESULTS

Sixty-six cases and 67 controls were included in the study. Maternal omega 3 supplement consumption during pregnancy was significantly less common among cases of IHPS as compared with controls (P = 0.031). Consumption of omega 3 supplement was defined as consumption of at least 1 to 2 per week during the pregnancy period. Following adjustment for known risk factors, including male sex and maternal smoking, maternal omega 3 supplement consumption remained associated with a significantly lower risk of developing IHPS (odds ratio = 0.303, 95% confidence interval 0.111-0.828, P = 0.02).

CONCLUSIONS

Maternal omega 3 supplement consumption during pregnancy was associated with a significantly reduced risk of IHPS. Further studies are needed to support these results and investigate possible mechanisms of the effect of omega 3.

Stomach development, stem cells and disease

The stomach, an organ derived from foregut endoderm, secretes acid and enzymes and plays a key role in digestion. During development, mesenchymal-epithelial interactions drive stomach specification, patterning, differentiation and growth through selected signaling pathways and transcription factors. After birth, the gastric epithelium is maintained by the activity of stem cells. Developmental signals are aberrantly activated and stem cell functions are disrupted in gastric cancer and other disorders. Therefore, a better understanding of stomach development and stem cells can inform approaches to treating these conditions. This Review highlights the molecular mechanisms of stomach development and discusses recent findings regarding stomach stem cells and organoid cultures, and their roles in investigating disease mechanisms.

Genomic variants in the coding region of neuronal nitric oxide synthase (NOS1) in infantile hypertrophic pyloric stenosis

BACKGROUND

Infantile hypertrophic pyloric stenosis (IHPS) is a common childhood pathology affecting 1 to 5:1000 newborns, with a genetic background suggested by familial occurrence. Neuronal nitric oxide synthase (NOS1) is a candidate gene owing to its role in the relaxation of smooth musculature and the association of the -84g>a variant of NOS1 with IHPS.

METHODS

We investigated NOS1 through sequencing of the complete NOS1 coding region in DNA from 43 patients with IHPS compared the genotype frequencies to 47 controls using the Cochran-Armitage trend or Fisher exact tests.

RESULTS

We found 19 polymorphisms in the coding region of NOS1. The variants c.3827-42_3827-43 del_insTA and c.+276 c>t were more frequent in IHPS with statistically significant exact P values (P = .010 and P = .039, respectively) yet failed to show significance after Bonferroni adjustment for multiple testing. We have also found a marginally significant occurrence of the variants c.-460A (P = .065) and c.2823+15G (P = .076). There was a significant correlation between the variants c.2706C>T ⬄ c.2823+15A>G, (r(2) = 1.00) and c.3258 C>T ⬄ c.3235+31A>G (r(2) = 1.00).

CONCLUSIONS

We conclude that NOS1 variants are present in patients with IHPS yet show no significant statistical association with the IHPS phenotype, suggesting at best an adjuvant role for NOS1 in IHPS.

New insights into the pathogenesis of infantile pyloric stenosis

Infantile hypertrophic pyloric stenosis (IHPS) is the most common surgical cause of vomiting in infants. Despite numerous hypotheses, the aetiopathogenesis of IHPS is not fully understood. Genetic, extrinsic and hormonal factors have been implicated in the pathogenesis of the disease. Furthermore, abnormalities of various components of the pyloric muscle such as smooth muscle cells, growth factors, extracellular matrix elements, nerve and ganglion cells, synapses, nerve supporting cells, neurotransmitters and interstitial cells of Cajal have been reported. Recently, genetic studies have identified susceptibility loci for IHPS and molecular studies have concluded that smooth muscle cells are not properly innervated in IHPS.

The pylorus

The pylorus controls the flow between a reservoir dedicated to mechanical and chemical digestion (the stomach) and a conduit dedicated to the absorption of nutrients (the intestines). The pylorus adjusts gastric outflow resistance to physiological needs. It allows the outflow of isotonic fluids yet selectively retains particles too large for delivery to the intestines and in concert with the antrum further processes them (gastric sieving). Unlike most gut sphincters, the pylorus, at least of man, maintains a patent lumen most of the time. It only intermittently becomes a tightly closed barrier that arrests all flow out of and into the stomach. The geometry of the pylorus changes dramatically from the relaxed open state to closure. Pyloric closure involves contraction of its proximal and distal muscle loops, and occlusion of its lumen by mucosal folds. Current studies that combine pressure recordings with imaging by magnetic resonance imaging or ultrasound and fluid-mechanical analysis shed new light on the role of the pylorus in gastric emptying and digestion. Much has been learned in recent years on the innervation of the normal pylorus particularly from studies on infantile hypertrophic stenosis, and attempts are being made to treat gastroparesis by interventions on the pylorus.

Development of neural tissue and airway smooth muscle in fetal mouse lung explants: a role for glial-derived neurotrophic factor in lung innervation

We have characterized the distribution of neural tissue and its primary target tissue, airway smooth muscle (ASM), in an in vitro mouse model of early lung development comprising left lung lobes at embryonic Day 12, cultured for 2 or 5 d. Neural tissue was detected with antibodies to protein gene product 9.5 (PGP 9.5), synapsin, and p75NTR (the low-affinity neurotrophin receptor), and smooth muscle with an antibody to alpha-actin. Imaging by confocal microscopy revealed few PGP 9.5-positive neurons at the start of culture; after 2 d clusters of neurons and nerve fibers had appeared along the lobar bronchus and after 5 d along the secondary and tertiary branches. Neural tissue did not just follow the smooth muscle-covered tubules, as seen in vivo, but also grew outside the lobes onto a wide layer of alpha-actin-positive cells, suggesting that smooth muscle may express a trophic factor that attracts nerves. Explants cultured with glial-derived neurotrophic factor (GDNF) exhibited a striking increase in the amount of p75NTR- and PGP 9.5-positive tissue outside the lobes, whereas GDNF-impregnated beads attracted neuronal precursors and influenced the direction of neurite extension. We show that the mouse lung explant is suitable for investigating trophic signals involved in pulmonary innervation and that GDNF may have a role in the early innervation of the developing airways.

Gastroduodenal disorders in children

The North American Society for Pediatric Gastroenterology and Nutrition published guidelines for the evaluation of children suspected of being infected with Helicobacter pylori. The stool antigen test for H. pylori, which was recently commercialized in the United States, was evaluated in two high-risk pediatric populations. The results are encouraging but should be interpreted with caution. A number of studies suggest that delayed gastric emptying may accompany a variety of disorders, or may be a cause of vomiting. The outcome of children with dyspeptic symptoms is described, and the results will be helpful in reassuring anxious parents. Studies examining the development of H, K-adenosine triphosphatase in infants and the role of enteric glial cells in infantile hypertrophic pyloric stenosis are discussed. A study of neonates with allergic gastroenteropathy suggests that this disorder may be more common in this age group than generally thought.

Selective neurotrophin deficiency in infantile hypertrophic pyloric stenosis

BACKGROUND/PURPOSE

Increasing evidence suggests that the enteric nervous system is under the control of neurotrophins. Nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4/5 (NT-4/5), promote differentiation, growth, and survival of various central and peripheral nervous system neurons. The biological effects of neurotrophins are mediated by the interactions with high-affinity tyrosine kinase receptors (TrkA, TrkB, TrkC). Recently, abnormalities of intramuscular innervation have been reported in infantile hypertrophic pyloric stenosis (IHPS). To further understand the reported abnormalities in pyloric innervation in IHPS, the authors analyzed the expression of Trk receptors and the neurotrophins content in IHPS.

METHODS

Full-thickness muscle biopsy specimens were obtained from 8 IHPS patients (age range, 23 to 41 days) at pyloromyotomy and from 8 age-matched controls without gastrointestinal disease at autopsy performed within 12 hours after death. Indirect immunohistochemistry was performed using ABC (Avidin Biotin peroxidase Complex) method with anti-Trk specific antibodies (A,B,C). Quantitative analysis was performed using sandwich-type ELISA for NGF, BDNF, NT-3, and NT-4/5.

RESULTS

The intensity of staining of the myenteric plexus for TrkA, TrkB, and TrkC was similar among IHPS and controls. There was a lack of TrkA-positive nerve fibers in IHPS compared with controls. The quantity of total NGF, NT-3, and BDNF in IHPS was significantly lower than in controls.

CONCLUSIONS

The reduced production of neurotrophins in IHPS may be responsible for the delay in the functional and structural maturation of pyloric innervation in IHPS. The lack of TrkA-positive nerve fibers in pyloric muscle may explain the abnormal intramuscular innervation in IHPS.