Developmental study of tethered spinal cord in murine embryos with anorectal malformations

doi:10.1016/j.jpedsurg.2005.08.009

Journal of Pediatric Surgery

Volume 40, Issue 12, December 2005, Pages 1927-1930

https://doi.org/10.1016/j.jpedsurg.2005.08.009 Get rights and content

Abstract

Background/Purpose

Tethered spinal cord is frequently associated with anorectal malformations (ARMs). However, it remains unknown how the tethered spinal cord develops and relates to the severity of ARM. We studied the development of the spinal cord in ARM mouse embryos induced by all-trans retinoic acid (ATRA).

Methods

Pregnant ICR-Slc mice were administered 100 mg/kg of ATRA on the ninth embryonic day (E9.0). Embryonic specimens were obtained from the uteri between E11.0 and E18.5. Midsagittal histologic sections focusing on the spinal cord and pelvis were prepared for immuonhistochemistry specific for neurofilament and Protein Gene Product 9.5 molecules.

Results

More than 98% of ATRA-treated embryos demonstrated ARM with rectourethral or rectocloacal fistula. Normal embryos exhibited progressive ascent of the spinal cord from E14.5. However, in ARM embryos, the distal spinal cord ended with meningomyelocelelike or atypical hamartomatous lesions at E11.5 to E13.5, which later caused stretch force that damaged the spinal cord, resulting in tethered cord between E16.0 and E16.5.

Conclusions

In ATRA-induced ARM mouse embryos, tethered spinal cord was mostly established, accompanied by caudal neural maldevelopment, during early fetal development. This experimental model may be useful for researching detailed neuropathologic conditions in ARM children accompanied with tethered spinal cord.

Section snippets

Induction of ARM model embryos using ATRA

The ICR-Slc mice were obtained from Japan SLC Inc (Hamamatsu, Japan), and a breeding colony was maintained in a heat- and humidity-controlled vivarium. Presence of a vaginal plug was regarded as evidence of successful mating and was designated as day 0 of gestation (E0). Pregnant ICR-Slc mice were administered 100 mg/kg of ATRA dissolved in sesame oil via gavage on the ninth embryonic day (E9.0). Embryos were removed from the uteri between E11.0 and E18.5 using a dissecting microscope (Model

Anorectal malformation model embryos and phenotypic presentations

Among the ATRA-treated embryos, 1.5% to 2.0% died in utero. The overall survival rate of the fetuses was more than 98%, and all had a short tail and imperforate anus. Preliminary histologic analysis showed that the most frequent anorectal anomalies were rectoprostatic urethral and rectocloacal fistulas in the male and the females, respectively [9].

Development of the spinal cord in ATRA-induced ARM embryos

Immunoreactivities specific to neurofilament and PGP 9.5 molecules were detected in all histologic specimens between E11.0 and E18.5. The developing

Discussion

The association of tethered spinal cord in patients with ARMs has been described [2], [4]. In recent years, high-resolution diagnostic equipment such as spinal magnetic resonance imaging and 3-dimensional computed tomography have demonstrated a higher frequency of tethered cord in the setting of ARMs than previously estimated [5], [10]. However, it remains controversial whether or when the tethered cord should be surgically corrected because of the ambiguity of neurologic manifestations from

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Cited by (4)

Spinal dysraphism with anorectal malformation: lumbosacral magnetic resonance imaging evaluation of 120 patients
2010, Journal of Pediatric Surgery
Citation Excerpt :
In those patients, a bowel management program including antegrade continence enema procedure was necessary. One possible explanation is because an animal experiment showing that neurologic pathways controlling urinary and fecal continence may be established during early embryogenesis [40]. Another important aspect of spinal cord tethering is that it is not a static condition, with several reports of progressive neurologic deficit in children with tethered cord syndrome [38,41].
We evaluated the prevalence of spinal dysraphism (SD) in patients with anorectal malformation (ARM) by magnetic resonance imaging (MRI).
From January 2002 to March 2009, 120 patients with ARM who underwent anorectal reconstruction were evaluated for SD with sacral plain film, spinal ultrasonography (US), and lumbosacral MRI. We adopted Krickenbeck international classification of ARM.
Spinal dysraphism was present in 41 (34.2%) of 120 patients with ARM, 3 (13.0%) of 23 patients with perineal fistula, 7 (29.2%) of 24 patients with vestibular fistula, 4 (36.4%) of 11 patients with rectovesical fistula, 18 (40.9%) of 44 patients with rectourethral fistula, and 9 (60.0%) of 15 patients with cloacal anomaly (P = .04). Among 41 patients having SD detected by MR, 26 patients (26/41; 63.4%) underwent detethering surgery for tethered spinal cord. The mean sacral ratio (SR) in patients who underwent detethering surgery (0.54 ± 0.19) was significantly lower than in patients who did not undergo detethering surgery (0.69 ± 0.13; P < .001). The optimal cutoff for the SR value predicting SD requiring detethering surgery was 0.605, with sensitivity of 65.4% and specificity of 77.7%.
Spinal dysraphism is common in patients with ARM, and its prevalence is higher in patients with complex ARM. Spinal anomalies can occur even with benign types of ARM and, therefore, that all patients should be screened. Magnetic resonance imaging is useful in detecting occult SD that may be missed by conventional radiologic evaluation, physical examination, and spinal US. We further recommend a lumbosacral MRI examination in those whose SR is lower than 0.6.
Abnormal development of intrinsic innervation in murine embryos with anorectal malformations
2012, Pediatric Surgery International
PCSK5 and GDF11 expression in the hindgut region of mouse embryos with anorectal malformations
2011, European Journal of Pediatric Surgery
Bowel function after surgery for anorectal malformations in patients with tethered spinal cord
2007, Pediatric Surgery International

: Presented at the 38th Annual Meeting of the Pacific Association of Pediatric Surgeons, May 22-26, 2005, Vancouver, Canada.

^☆: This work was supported by grants-in-aid for scientific research from Japan Society for the Promotion of Science, Tokyo, Japan (17591866, 15390534, and 13557146).

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Developmental study of tethered spinal cord in murine embryos with anorectal malformations☆

Abstract

Background/Purpose

Methods

Results

Conclusions

Section snippets

Induction of ARM model embryos using ATRA

Anorectal malformation model embryos and phenotypic presentations

Development of the spinal cord in ATRA-induced ARM embryos

Discussion

J Pediatr Surg

J Pediatr Surg

Brain Res

J Pediatr Surg

J Pediatr Surg

J Urol

J Pediatr Surg

J Pediatr Surg

J Pediatr Surg