Elsevier

Theriogenology

Volume 84, Issue 6, 1 October 2015, Pages 995-1002
Theriogenology

Research article
Ectopic liver and gallbladder in a cloned dog: Possible nonheritable anomaly

https://doi.org/10.1016/j.theriogenology.2015.05.039Get rights and content

Abstract

Ectopic liver and gallbladder are rare anomalies usually not accompanied by any symptoms and are found during surgical exploration or autopsy. We aimed to find a cause of this anomaly using somatic cell nuclear transfer (SCNT) technology, which can produce genetically identical organisms. A cloned beagle having ectopic organs was produced and died on the day of birth. Major and ectopic organs were fixed and underwent histologic analysis. SCNT was performed using cells derived from the dead puppy to produce reclones. Normality of internal organs in the original donor dog and recloned dogs was evaluated by computed tomography. While a liver without the gallbladder was located in the abdominal cavity of the cloned dog, a well-defined, reddish brown mass with a small sac was also positioned outside of the thoracic cavity. Histologically, they presented as normal liver and gallbladder. Five reclones were produced, and computed tomography results revealed that the original donor dog and reclones had normal liver and gallbladder structure and location. This is the first report of both ectopic liver and gallbladder in an organism and investigation on the etiology of these abnormalities. Normal organ structure and position in the original donor dog and reclones suggests that the ectopic liver and gallbladder is a possible nonheritable anomaly.

Introduction

The term “choristoma” originally comes from the German word “to separate” and was introduced by Eugen Albrecht in 1904 to refer to a mass of normal tissue located at a site away from its usual location [1]. Choristoma occurring with hepatic or gallbladder tissue is commonly called ectopic or heterotopic liver or gallbladder. Ectopic liver and gallbladder have been recorded since the 19th century [2], but only less than 80 cases of ectopic liver were documented in a recent literature review [3] with lower than 0.5% [4] and 0.4% [5] incidences. Ectopic liver has been found in various sites including the gallbladder [3], [6], [7], spleen [8], pancreas [9], stomach [10], heart [11], lung [12] and suprahepatic inferior vena cava [13], [14], and ectopic gallbladder has been described in the intrahepatic [15] and suprahepatic region [16], and left hepatic lobe [17], [18]. Both anomalies are usually asymptomatic, but rare symptoms such as intra-abdominal bleeding due to ectopic liver [10] or epigastric pain caused by ectopic gallbladder [17] have been reported. Lack of symptoms usually results in discovery of these anomalies only during peritoneoscopy, laparotomy, or autopsy. Also, almost all the documented cases of these anomalies have been described in human beings, not in animals [1], [2], [3], [4], [5], [6], [8], [9], [10], [11], [12], [15], [16], [17], [18], [19], [20], [21]. In dogs, ectopic hepatocytes were firstly reported in 2005, in which a bearded collie had a firm and nonpainful mass in the left midabdominal region [22]. Consequently, scarcity of the anomaly, lack of symptoms, and absence of animal models have made it hard to define a cause of ectopic liver and gallbladder.

Somatic cell nuclear transfer (SCNT) is a process for producing genetically identical organisms asexually [23] which includes nuclear removal from a donor oocyte, donor cell injection into the empty perivitelline space, fusion between the cytoplast–cell couplet, and activation of the reconstructed embryo. Since the first cloned animal, Dolly the sheep, was produced using SCNT in 1997 [24], more than 16 mammalian species including mice [25], rats [26], cattle [27], pigs [28], cats [29], and dogs [30] have been successfully produced. Among these, dogs have advantages as animal models for human diseases because of the similarities in their size, longevity, and physiology to humans. Of the nearly 648 known hereditary diseases described in dogs, more than half (352) can be potential models for human diseases (http://omia.angis.org.au, January 2014). A human disease model dog can be generated by replacing a donor oocyte's nucleus with a cell derived from a dog naturally having a heritable disease or with a cell containing a genetically modified transgene [31], [32]. For example, a cloned puppy derived from a donor dog having hip dysplasia, which is an inherited disease characterized by hip subluxation and laxity [33], [34], also showed signs of hip dysplasia. Because of the identical genetic traits between donor and cloned dogs, SCNT can be used as a tool for studying potential causes of unidentified disease to determine whether it is caused by a genetic modification or not.

In the present study, we report for the first time an occurrence of both ectopic liver and gallbladder in a cloned dog and aimed to investigate their etiology by recloning using cells derived from the clone.

Section snippets

Animal use

Animal experiments were done following a standard procedure established by the Committee for Accreditation of Laboratory Animal Care and the Guideline for the Care and Use of Laboratory Animals of Seoul National University (approval number is SNU-121130-1).

Production of a cloned dog

Ear skin tissue from a 10-year-old male beagle (Fig. 1A) was collected and transferred to the laboratory aseptically. The tissue was minced and cultured with Dulbecco's modified Eagle's medium (Invitrogen, Carlsbad, CA, USA) supplemented with

Gross pathologic examination of ectopic organs found in a cloned dog

A cloned dog died on the day of birth because of cannibalism by its nanny dog. During the routine autopsy, ectopic organs assumed to be liver and gallbladder were found between the left-side ribs and the skin (Fig. 2A). Although there was a properly located liver (mother liver) with six lobes, no gallbladder was present in the abdominal cavity. Interestingly, there was a well-defined, large solid mass (6 × 4 × 0.5 cm) with a smooth surface and reddish brown color similar to the normal liver

Discussion

Ectopic organs are rare congenital abnormalities. Several organs including the liver [1], [2], [3], [4], [5], [6], [8], [9], [10], [11], [12], [15], [16], [17], [18], [19], gallbladder [5], [17], [19], pancreas [39], kidney [40], testis [41], and ovary [42] located in ectopic positions have been reported in humans. Because the aberrant tissue is often not accompanied by any clinical relevance [3], [19], [39], it has a low incidence rate and it is difficult to analyze the reason for its

Acknowledgments

This study was supported by Rural Development Administration (#PJ010928032015), Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, Forestry and Fisheries (#311062-04-3SB010), National Research Foundation of Korea (#2014R1A1A2059928), Research Institute for Veterinary Science, Natural Balance Korea, and the BK21 plus program. The authors thank Dr Barry D. Bavister for his valuable editing of the article.

References (58)

  • H.J. Oh et al.

    Recloned dogs derived from adipose stem cells of a transgenic cloned beagle

    Theriogenology

    (2011)
  • R.W. Strong et al.

    Surgical implications of a left-sided gallbladder

    Am J Surg

    (2013)
  • H.J. Oh et al.

    Improved efficiency of canine nucleus transfer using roscovitine-treated canine fibroblasts

    Theriogenology

    (2009)
  • A. Pinborg et al.

    Congenital anomalies after assisted reproductive technology

    Fertil Steril

    (2013)
  • E. Sheridan et al.

    Risk factors for congenital anomaly in a multiethnic birth cohort: an analysis of the Born in Bradford study

    Lancet

    (2013)
  • E. Albrecht

    Uber Hamartome

    Verh Dtsch Ges Pathol

    (1904)
  • T.S. Cullen

    Accessory lobes of the liver: an accessory hepatic lobe springing from the surface of the gallbladder

    Arch Surg

    (1925)
  • M. Catani et al.

    Ectopic liver nodules: a rare finding during cholecystectomy

    G Chir

    (2011)
  • M. Watanabe et al.

    Five cases of ectopic liver and a case of accessory lobe of the liver

    Endoscopy

    (1989)
  • K. Karaman et al.

    Ectopic liver (choristoma) attached to the gallbladder wall

    ANZ J Surg

    (2012)
  • K.A. Kim et al.

    Hepatocellular carcinoma in an ectopic liver: CT findings

    Eur Radiol

    (2003)
  • K. Kubota et al.

    Ectopic hepatocellular carcinoma arising from pancreas: a case report and review of the literature

    World J Gastroenterol

    (2007)
  • M. Arakawa et al.

    Propensity of ectopic liver to hepatocarcinogenesis: case reports and a review of the literature

    Hepatology

    (1999)
  • R.C. Schulz et al.

    Liver scanning and the intrahepatic gallbladder: case report

    J Nucl Med

    (1975)
  • L. Youngwirth et al.

    The suprahepatic gallbladder. An unusual anatomical variant

    Radiology

    (1983)
  • C. Chung et al.

    Ectopic gallbladder revisited, laparoscopically: a case report

    Can J Surg

    (1997)
  • V. Rafailidis et al.

    Two congenital anomalies in one: an ectopic gallbladder with phrygian cap deformity

    Case Rep Radiol

    (2014)
  • M.-J. van Kamp et al.

    A Phrygian cap

    Case Rep Gastroenterol

    (2013)
  • J. de Csepel et al.

    Soft-tissue images.“Phrygian cap” gallbladder

    Can J Surg

    (2003)
  • Cited by (3)

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