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Inherited liver shunts in dogs elucidate pathways regulating embryonic development and clinical disorders of the portal vein.

van Steenbeek FG, van den Bossche L, Leegwater PA, Rothuizen J - Mamm. Genome (2011)

Bottom Line: Both subtypes result in nearly complete bypass of the liver by the portal blood flow.The same pathways likely regulate the development of the vascular system of regenerating livers during liver diseases such as hepatitis and cirrhosis.Therefore, the identification of these molecular pathways may provide a basis for future proregenerative intervention.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Veterinary Medicine, Utrecht University, Yalelaan 104, PO Box 80154, 3508 TD Utrecht, The Netherlands. f.g.vansteenbeek@uu.nl

ABSTRACT
Congenital disorders of the hepatic portal vasculature are rare in man but occur frequently in certain dog breeds. In dogs, there are two main subtypes: intrahepatic portosystemic shunts, which are considered to stem from defective closure of the embryonic ductus venosus, and extrahepatic shunts, which connect the splanchnic vascular system with the vena cava or vena azygos. Both subtypes result in nearly complete bypass of the liver by the portal blood flow. In both subtypes the development of the smaller branches of the portal vein tree in the liver is impaired and terminal branches delivering portal blood to the liver lobules are often lacking. The clinical signs are due to poor liver growth, development, and function. Patency of the ductus venosus seems to be a digenic trait in Irish wolfhounds, whereas Cairn terriers with extrahepatic portosystemic shunts display a more complex inheritance. The genes involved in these disorders cannot be identified with the sporadic human cases, but in dogs, the genome-wide study of the extrahepatic form is at an advanced stage. The canine disease may lead to the identification of novel genes and pathways cooperating in growth and development of the hepatic portal vein tree. The same pathways likely regulate the development of the vascular system of regenerating livers during liver diseases such as hepatitis and cirrhosis. Therefore, the identification of these molecular pathways may provide a basis for future proregenerative intervention.

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Overview of the anatomy of a normal liver and of livers with intra- and extrahepatic portosystemic shunts. a No connection of blood vessels in the liver is seen within a normal liver resulting in a blood flow through the hepatic sinusoids. b In case of PSS, blood bypasses the liver sinusoids and is therefore not subjected to hepatic metabolism. The intrahepatic shunt represents an abnormal connection of the portal vein with the systemic circulation, which is seen inside the liver. c In the case of an extrahepatic shunt, the aberrant connection is located outside the liver
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Fig1: Overview of the anatomy of a normal liver and of livers with intra- and extrahepatic portosystemic shunts. a No connection of blood vessels in the liver is seen within a normal liver resulting in a blood flow through the hepatic sinusoids. b In case of PSS, blood bypasses the liver sinusoids and is therefore not subjected to hepatic metabolism. The intrahepatic shunt represents an abnormal connection of the portal vein with the systemic circulation, which is seen inside the liver. c In the case of an extrahepatic shunt, the aberrant connection is located outside the liver

Mentions: Congenital portosystemic shunts can be divided roughly into two main subtypes: intrahepatic (IHPSS) and extrahepatic shunts (EHPSS) (van den Ingh et al. 1995) (Fig. 1). Although the genetic basis of CPSS in dogs is not clear yet, many authors have demonstrated that congenital shunts are more frequently diagnosed in purebred dogs and that a number of breeds are predisposed to it (Hunt 2004; Tobias 2003), which indicates an inherited basis for this disease (Meyer and Rothuizen 1991; van Straten et al. 2005). An equal frequency of affected males and females was generally reported (Hunt 2004; van Straten et al. 2005). In addition, EHPSS and IHPSS were very rarely seen in the same breed (Hunt 2004; Krotscheck et al. 2007; Martin 1993; Tobias and Rohrbach 2003; Vulgamott 1985; Winkler et al. 2003). Intrahepatic shunts were diagnosed mainly in large dog breeds and extrahepatic shunts in the smaller and toy breeds (Tobias and Rohrbach 2003; Tisdall et al. 1994). CPSS in humans has been classified as being a rare disease (Stringer 2008).Fig. 1


Inherited liver shunts in dogs elucidate pathways regulating embryonic development and clinical disorders of the portal vein.

van Steenbeek FG, van den Bossche L, Leegwater PA, Rothuizen J - Mamm. Genome (2011)

Overview of the anatomy of a normal liver and of livers with intra- and extrahepatic portosystemic shunts. a No connection of blood vessels in the liver is seen within a normal liver resulting in a blood flow through the hepatic sinusoids. b In case of PSS, blood bypasses the liver sinusoids and is therefore not subjected to hepatic metabolism. The intrahepatic shunt represents an abnormal connection of the portal vein with the systemic circulation, which is seen inside the liver. c In the case of an extrahepatic shunt, the aberrant connection is located outside the liver
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3275728&req=5

Fig1: Overview of the anatomy of a normal liver and of livers with intra- and extrahepatic portosystemic shunts. a No connection of blood vessels in the liver is seen within a normal liver resulting in a blood flow through the hepatic sinusoids. b In case of PSS, blood bypasses the liver sinusoids and is therefore not subjected to hepatic metabolism. The intrahepatic shunt represents an abnormal connection of the portal vein with the systemic circulation, which is seen inside the liver. c In the case of an extrahepatic shunt, the aberrant connection is located outside the liver
Mentions: Congenital portosystemic shunts can be divided roughly into two main subtypes: intrahepatic (IHPSS) and extrahepatic shunts (EHPSS) (van den Ingh et al. 1995) (Fig. 1). Although the genetic basis of CPSS in dogs is not clear yet, many authors have demonstrated that congenital shunts are more frequently diagnosed in purebred dogs and that a number of breeds are predisposed to it (Hunt 2004; Tobias 2003), which indicates an inherited basis for this disease (Meyer and Rothuizen 1991; van Straten et al. 2005). An equal frequency of affected males and females was generally reported (Hunt 2004; van Straten et al. 2005). In addition, EHPSS and IHPSS were very rarely seen in the same breed (Hunt 2004; Krotscheck et al. 2007; Martin 1993; Tobias and Rohrbach 2003; Vulgamott 1985; Winkler et al. 2003). Intrahepatic shunts were diagnosed mainly in large dog breeds and extrahepatic shunts in the smaller and toy breeds (Tobias and Rohrbach 2003; Tisdall et al. 1994). CPSS in humans has been classified as being a rare disease (Stringer 2008).Fig. 1

Bottom Line: Both subtypes result in nearly complete bypass of the liver by the portal blood flow.The same pathways likely regulate the development of the vascular system of regenerating livers during liver diseases such as hepatitis and cirrhosis.Therefore, the identification of these molecular pathways may provide a basis for future proregenerative intervention.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Veterinary Medicine, Utrecht University, Yalelaan 104, PO Box 80154, 3508 TD Utrecht, The Netherlands. f.g.vansteenbeek@uu.nl

ABSTRACT
Congenital disorders of the hepatic portal vasculature are rare in man but occur frequently in certain dog breeds. In dogs, there are two main subtypes: intrahepatic portosystemic shunts, which are considered to stem from defective closure of the embryonic ductus venosus, and extrahepatic shunts, which connect the splanchnic vascular system with the vena cava or vena azygos. Both subtypes result in nearly complete bypass of the liver by the portal blood flow. In both subtypes the development of the smaller branches of the portal vein tree in the liver is impaired and terminal branches delivering portal blood to the liver lobules are often lacking. The clinical signs are due to poor liver growth, development, and function. Patency of the ductus venosus seems to be a digenic trait in Irish wolfhounds, whereas Cairn terriers with extrahepatic portosystemic shunts display a more complex inheritance. The genes involved in these disorders cannot be identified with the sporadic human cases, but in dogs, the genome-wide study of the extrahepatic form is at an advanced stage. The canine disease may lead to the identification of novel genes and pathways cooperating in growth and development of the hepatic portal vein tree. The same pathways likely regulate the development of the vascular system of regenerating livers during liver diseases such as hepatitis and cirrhosis. Therefore, the identification of these molecular pathways may provide a basis for future proregenerative intervention.

Show MeSH
Related in: MedlinePlus