Xenoimplant of Collagen Matrix Scaffold in Liver Tissue as a Niche for Liver Cells

Abstract

Hepatitis C virus-induced liver damage, chronic liver damage due to alcohol, and non-alcoholic liver disease-induced cellular alterations promote fibrosis, cirrhosis, and/or hepatocellular carcinoma. The recommended therapeutic option for advanced liver damage is liver transplantation. Extracellular matrix scaffolds have been evaluated as an alternative for tissue restoration. Studies on the biocompatibility and rejection of synthetic and natural scaffolds as an alternative to organ transplantation have been evaluated. Our group has recently described the xenoimplant of collagen matrix scaffold (CMS) in a rat model. However, no complete macroscopic and histological description of the liver parenchyma at the initial (day 3), intermediate (day 14), and advanced (day 21) stages has been obtained. In this study, we described and compared liver tissue from the CMS zone (CZ, CMS, and liver parenchyma), liver tissue from the normal zone (liver parenchyma close to the CMS), and basal tissue (resected tissue from the CMS implantation site). Our data strongly suggest that the collagen matrix xenoimplant is a good niche for hepatocytes, with no rejection, and does not affect liver function tests. The liver can regenerate after damage, but this capacity is inhibited in a chronic injury. At present, the use of CMS after liver damage has not been reported. This biomaterial could be a novel alternative in the field of regenerative medicine for liver diseases.

Keywords: animal model; cell niche; collagen matrix scaffold; liver; xenoimplant.

FIGURE 1

Animal groups. (A) Rats without hepatectomy (sham). Right inset, normal hepatic parenchyma. (B) Rats with partial hepatectomy (PH). Triangular dissected basal tissue (inset). (C) Rats with PH + CMS. Normal liver zone (upper inset), regeneration area where the collagen matrix scaffold (CMS) was implanted (lower inset). (D) Timeline with the experimental design.

FIGURE 2

Macroscopic evaluation of animals after surgical procedures. Representative laparoscopy examination of the sham (A) and PH (B) animals at day 21; analysis showed normal organs. The PH group showed a scar at the 40% hepatectomy site (arrow). The PH + CMS group at days 3 (C), 14 (D), and 21 (E) showed evident adipose tissue surrounding the xenoimplant (circles) but with no adjacent organ alteration or infection.

FIGURE 3

Histological analysis at day 3. (A) The liver without hepatectomy (sham) with triad portal (arrow), 100×. (B) In the PH group, the biliary duct (arrow) and hepatic artery (arrowhead) are shown, 400×. (C) Basal tissue from the animals at implantation day 3, in which the typical arrangement of liver parenchyma and portal triads are observed (arrows), 100×. (D–I) PH + CMS animals. (D) Normal zone (NZ) and CMS zone (CZ), liver tissue with CMS (arrows), 40×. (E) CMS zone (RZ) at high magnification, 100×. (F) Trabeculae and pore of CMS, 400×. (G,H) Hepatocyte-like cells (arrows) around the CMS, 100×. (I) Inflammatory cells (arrows) in the CMS, 100×. Representative images with Masson’s trichrome staining.

FIGURE 4

Histological events at day 14 of evolution. (A) Representative sham animals showed portal triads (arrow) and normal parenchyma, 100×. (B) PH group: central vein is shown (arrow), 400×. (C) Basal fragments from animals at day 14 displayed the normal distribution of hepatocyte cords and Küpffer cells (arrowhead), 400×. (D–I) PH + CMS. (D) CMS zone (CZ), ductular reaction shown (arrows), and multifocal areas of inflammation (asterisks). Normal zone (NZ) showed a typical parenchyma arrangement, 40×. (E) The CZ showed CMS with great neovascularization (arrowheads) and fibroplasia (arrow) between CMS, 40×. (F,G) At the limits of the CZ, a ductular reaction is observed in both the NZ and CZ (arrows), 400×. (H) CZ with neovascularization (arrows) between the CMS, 400×. (I) Areas of granulomatous inflammation with giant cells (arrows). Representative images with Masson’s trichrome staining.

FIGURE 5

Nodules of the hepatic cell at CMS implantation day 21. (A) The liver without hepatectomy (sham), portal triads (arrow), and central vein (arrowheads), 40×. (B) PH sample, the central vein is shown (arrow), 100×. (C) Basal tissue from animals evaluated up to day 21, hepatocyte cords and two central veins (arrows), 100×. (D–I) PH + CMS implantation at day 21. (D) CMS zone (CZ) and cell nodules (arrows), 40×. (E) Boundaries between the NZ and the CMS with ductular reaction (arrow), vessels (asterisk) 100×. (F) Limits between the nodules (N) and CMS, vessels (asterisks), 400×. (G,H) Nodules of liver tissue (arrow) in the CMS, 10×. (I) Hepatocytes and Küpffer cells in nodules at high magnification, 400×. Images with Masson’s trichrome staining.