Endoscopic muscle biopsy sampling of the duodenum and rectum: a pilot survival study in a porcine model to detect myenteric neurons

Pediatric Intestinal Pseudo-Obstruction: Progress and Challenges

BACKGROUND

Chronic intestinal pseudo-obstruction is a rare disorder and represents the most severe form of gastrointestinal dysmotility with significant morbidity and mortality. Emerging research shows considerable differences between the adult and pediatric population with intestinal pseudo-obstruction and the term Pediatric Intestinal Pseudo-Obstruction (PIPO) was recently proposed.

PURPOSE

The aim of this article is to provide pediatric gastroenterologists and pediatricians with an up to date review of the etiology and underlining pathophysiology, clinical features, diagnostic and management approaches currently available for PIPO and to discuss future perspectives for the diagnosis and management of this rare disease.

microRNA overexpression in slow transit constipation leads to reduced NaV1.5 current and altered smooth muscle contractility

OBJECTIVE

This study was designed to evaluate the roles of microRNAs (miRNAs) in slow transit constipation (STC).

DESIGN

All human tissue samples were from the muscularis externa of the colon. Expression of 372 miRNAs was examined in a discovery cohort of four patients with STC versus three age/sex-matched controls by a quantitative PCR array. Upregulated miRNAs were examined by quantitative reverse transcription qPCR (RT-qPCR) in a validation cohort of seven patients with STC and age/sex-matched controls. The effect of a highly differentially expressed miRNA on a custom human smooth muscle cell line was examined in vitro by RT-qPCR, electrophysiology, traction force microscopy, and ex vivo by lentiviral transduction in rat muscularis externa organotypic cultures.

RESULTS

The expression of 13 miRNAs was increased in STC samples. Of those miRNAs, four were predicted to target SCN5A, the gene that encodes the Na⁺ channel Na_V1.5. The expression of SCN5A mRNA was decreased in STC samples. Let-7f significantly decreased Na⁺ current density in vitro in human smooth muscle cells. In rat muscularis externa organotypic cultures, overexpression of let-7f resulted in reduced frequency and amplitude of contraction.

CONCLUSIONS

A small group of miRNAs is upregulated in STC, and many of these miRNAs target the SCN5A-encoded Na⁺ channel Na_V1.5. Within this set, a novel Na_V1.5 regulator, let-7f, resulted in decreased Na_V1.5 expression, current density and reduced motility of GI smooth muscle. These results suggest Na_V1.5 and miRNAs as novel diagnostic and potential therapeutic targets in STC.

Endoscopic full-thickness muscle biopsy for rectal tissue sampling in patients with severe gut motility disorders: an initial experience (with video)

BACKGROUND AND AIMS

Diagnosis of GI neuromuscular diseases is mostly on the basis of symptomatology and is often unreliable. Pathologic analysis of affected tissue (eg, the myenteric plexus and muscle) is a potentially valuable method for both diagnosis and advancement of our knowledge about the biologic basis for these syndromes. However, until now access to the deeper layers of the GI tract has been limited, generally requiring invasive surgical techniques.

METHODS

We report a "close-then-resect" endoscopic full-thickness biopsy sampling (EFTB) technique using an over-the-scope clip and telescope for rectal muscle biopsy sampling in patients with suspected severe neuromuscular gut disorders. The main outcome measures were technical success and adverse events.

RESULTS

Thirteen patients (11 women; mean age 27 ± 5.4 years) with diffusely delayed colonic transit underwent EFTB. The mean (± standard deviation) procedure time was 30 ± 5.2 minutes. The mean size of the resected specimen was 18 ± 3.5 mm. Histologic full-thickness tissue samples were achieved for all patients. Postprocedural adverse events were reported in 2 patients, and both were graded as mild (1 self-limited bleeding and 1 with rectal pain). Hematoxylin and eosin staining of tissue samples confirmed adequate cross-sectional imaging of muscularis propria in all patients with excellent demonstration of the myenteric plexus and both layers of muscle. Two patients demonstrated a decrease in interstitial cells of Cajal as demonstrated by CD117 staining. No cases demonstrated appreciable inflammation involving myenteric ganglia.

CONCLUSIONS

Diagnostic EFTB with modified over-the-scope clip for the close-then-resect method appears to be a safe and effective technique to obtain adequate full-thickness rectal specimens, allowing for both quantitative and qualitative analysis for the diagnosis of neuromuscular GI dysmotility.

Gastroparesis

Gastroparesis is a disorder characterized by delayed gastric emptying of solid food in the absence of a mechanical obstruction of the stomach, resulting in the cardinal symptoms of early satiety, postprandial fullness, nausea, vomiting, belching and bloating. Gastroparesis is now recognized as part of a broader spectrum of gastric neuromuscular dysfunction that includes impaired gastric accommodation. The overlap between upper gastrointestinal symptoms makes the distinction between gastroparesis and other disorders, such as functional dyspepsia, challenging. Thus, a confirmed diagnosis of gastroparesis requires measurement of delayed gastric emptying via an appropriate test, such as gastric scintigraphy or breath testing. Gastroparesis can have idiopathic, diabetic, iatrogenic, post-surgical or post-viral aetiologies. The management of gastroparesis involves: correcting fluid, electrolyte and nutritional deficiencies; identifying and treating the cause of delayed gastric emptying (for example, diabetes mellitus); and suppressing or eliminating symptoms with pharmacological agents as first-line therapies. Several novel pharmacologic agents and interventions are currently in the pipeline and show promise to help tailor individualized therapy for patients with gastroparesis.

Endoscopic techniques for full thickness intestinal biopsy

PURPOSE OF REVIEW

Accurate diagnosis of gastrointestinal neuromuscular diseases requires full thickness biopsy for adequate histologic evaluation of the enteric neuromuscular and ancillary cells. Historically, this has been achieved by surgical approaches. An overview of procedure evolution and current techniques of endoscopic full thickness biopsy (EFTB) for diagnosis of gastrointestinal neuromuscular disorders will be presented.

RECENT FINDINGS

Emergence and advancement of endoscopic full thickness resection techniques has offered a less invasive, nevertheless an effective modality of tissue acquirement. Recently, clip-assisted close-then-cut EFTB has been utilized in clinical practice under research protocol. Early experience has shown that this technique provides an adequate full-thickness specimen including the myenteric plexus and ganglia cells, with acceptable safety profiles.

SUMMARY

EFTB is a promising means in diagnosing the nature of the disease and guiding therapy. Available animal and human studies have shown the noninferiority of endoscopic methods to surgical ones in term of adequacy of tissue samples, while potentially decreasing the risk and occurrence of complications. Further large prospective studies are needed to assess its efficacy, safety and impacts on patient's outcomes.