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Immunohistochemical studies of stellate cells in experimental cholestasis in newborn and adult rats.

Gibelli NE, Tannuri U, Mello ES - Clinics (Sao Paulo) (2008)

Bottom Line: Hepatic biopsies were obtained and immunohistochemical semi-quantification of desmin and alpha-SMA expression was performed in hepatic stellate cells and in myofibroblasts in the portal space, and between the portal space and the liver lobule.The differences between the groups for alpha-SMA expression were less significant than for desmin.These findings indicate that there is an increase in the number of collagen-producing myofibroblast cells in young animals, suggesting that there is more intense fibrosis in this population.

View Article: PubMed Central - PubMed

Affiliation: Pediatric Surgery and Pediatric Liver Transplantation Divisions, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.

ABSTRACT

Background and aims: Although there is much known about liver diseases, some aspects remain unclear, such as the nature of the differences between the diseases observed in newborn infants and those in adults. For example, how do newborns respond to duct epithelial cell injury? Do the stellate cells in newborns respond similarly to those in adults during biliary obstruction?

Methods: Ninety newborn Wistar rats aged six days, weighing 8.0 - 13.9 g each, and 90 adult rats weighing 199.7 - 357.0 g each, were submitted to bile duct ligation. After surgery, they were randomly divided and sacrificed on the 3rd, 5th, 7th, 14th, 21st or 28th day post-bile duct ligation. Hepatic biopsies were obtained and immunohistochemical semi-quantification of desmin and alpha-SMA expression was performed in hepatic stellate cells and in myofibroblasts in the portal space, and between the portal space and the liver lobule.

Results: Desmin expression in the myofibroblast cells post-bile duct ligation was higher in young rats, reaching its peak level in a shorter time when compared to the adult animals. The differences between the groups for alpha-SMA expression were less significant than for desmin.

Conclusions: These findings indicate that there is an increase in the number of collagen-producing myofibroblast cells in young animals, suggesting that there is more intense fibrosis in this population. This finding may explain why young animals with bile duct obstruction experience more intense portal fibrosis that is similar to the pathology observed in the livers of newborns with biliary atresia.

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Related in: MedlinePlus

Bar chart showing the expression of desmin at each phase of the experiment in young rats (YR) and adult rats (AR). The values expressed are medians
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f1-19-0084: Bar chart showing the expression of desmin at each phase of the experiment in young rats (YR) and adult rats (AR). The values expressed are medians

Mentions: On the 5th day after operation, desmin expression increased to a similar extent in both groups. However, from the 7th day onwards, higher levels of desmin expression were observed in the young animals, reaching a maximum value on the 14th day after the operation. In contrast, desmin expression in the adult animals reached its maximum value only on the 28th day. In addition, desmin expression in myofibroblasts located in the interface zone between the portal space and the lobule reached higher levels in a shorter period of time in the young animals when compared to the adult animals. However, the portal myofibroblasts showed a very weak and constant staining intensity throughout the observation period after BDL. The expression of desmin in the portal myofibroblasts was higher in the young animals (Figure 1).


Immunohistochemical studies of stellate cells in experimental cholestasis in newborn and adult rats.

Gibelli NE, Tannuri U, Mello ES - Clinics (Sao Paulo) (2008)

Bar chart showing the expression of desmin at each phase of the experiment in young rats (YR) and adult rats (AR). The values expressed are medians
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2664729&req=5

f1-19-0084: Bar chart showing the expression of desmin at each phase of the experiment in young rats (YR) and adult rats (AR). The values expressed are medians
Mentions: On the 5th day after operation, desmin expression increased to a similar extent in both groups. However, from the 7th day onwards, higher levels of desmin expression were observed in the young animals, reaching a maximum value on the 14th day after the operation. In contrast, desmin expression in the adult animals reached its maximum value only on the 28th day. In addition, desmin expression in myofibroblasts located in the interface zone between the portal space and the lobule reached higher levels in a shorter period of time in the young animals when compared to the adult animals. However, the portal myofibroblasts showed a very weak and constant staining intensity throughout the observation period after BDL. The expression of desmin in the portal myofibroblasts was higher in the young animals (Figure 1).

Bottom Line: Hepatic biopsies were obtained and immunohistochemical semi-quantification of desmin and alpha-SMA expression was performed in hepatic stellate cells and in myofibroblasts in the portal space, and between the portal space and the liver lobule.The differences between the groups for alpha-SMA expression were less significant than for desmin.These findings indicate that there is an increase in the number of collagen-producing myofibroblast cells in young animals, suggesting that there is more intense fibrosis in this population.

View Article: PubMed Central - PubMed

Affiliation: Pediatric Surgery and Pediatric Liver Transplantation Divisions, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.

ABSTRACT

Background and aims: Although there is much known about liver diseases, some aspects remain unclear, such as the nature of the differences between the diseases observed in newborn infants and those in adults. For example, how do newborns respond to duct epithelial cell injury? Do the stellate cells in newborns respond similarly to those in adults during biliary obstruction?

Methods: Ninety newborn Wistar rats aged six days, weighing 8.0 - 13.9 g each, and 90 adult rats weighing 199.7 - 357.0 g each, were submitted to bile duct ligation. After surgery, they were randomly divided and sacrificed on the 3rd, 5th, 7th, 14th, 21st or 28th day post-bile duct ligation. Hepatic biopsies were obtained and immunohistochemical semi-quantification of desmin and alpha-SMA expression was performed in hepatic stellate cells and in myofibroblasts in the portal space, and between the portal space and the liver lobule.

Results: Desmin expression in the myofibroblast cells post-bile duct ligation was higher in young rats, reaching its peak level in a shorter time when compared to the adult animals. The differences between the groups for alpha-SMA expression were less significant than for desmin.

Conclusions: These findings indicate that there is an increase in the number of collagen-producing myofibroblast cells in young animals, suggesting that there is more intense fibrosis in this population. This finding may explain why young animals with bile duct obstruction experience more intense portal fibrosis that is similar to the pathology observed in the livers of newborns with biliary atresia.

Show MeSH
Related in: MedlinePlus