Effect of human amniotic epithelial cells on pro-fibrogenic resident hepatic cells in a rat model of liver fibrosis

Myofibroblasts are key fibrogenic cells responsible for excessive extracellular matrix synthesis characterizing the fibrotic lesion. In liver fibrosis, myofibroblasts derive either from activation of hepatic stellate cells (HSC) and portal fibroblasts (PF), or from the activation of fibroblasts that originate from ductular epithelial cells undergoing epithelial-mesenchymal transition. Ductular cells can also indirectly promote myofibroblast generation by activating TGF-\uce\ub2, the main fibrogenic growth factor, through \uce\ub1v\uce\ub26 integrin. In addition, after liver injury, liver sinusoidal cells can lose their ability to maintain HSC quiescence, thus favouring HSC differentiation towards myofibroblasts. The amniotic membrane and epithelial cells (hAEC) derived thereof have been shown to decrease hepatic myofibroblast levels in rodents with liver fibrosis. In this study, in a rat model of liver fibrosis, we investigated the effects of hAEC on resident hepatic cells contributing to myofibroblast generation. Our data show that hAEC reduce myofibroblast numbers with a consequent reduction in fibronectin and collagen deposition. Interestingly, we show that hAEC strongly act on specific myofibroblast precursors. Specifically, hAEC reduce the activation of PF rather than HSC. In addition, hAEC target reactive ductular cells by inhibiting their proliferation and \uce\ub1v\uce\ub26 integrin expression, with a consequent decrease in TGF-\uce\ub2 activation. Moreover, hAEC counteract the transition of ductular cells towards fibroblasts, while it does not affect injury-induced and fibrosis-promoting sinusoidal alterations. In conclusion, among the emerging therapeutic applications of hAEC in liver diseases, their specific action on PF and ductular cells strongly suggests their application in liver injuries involving the expansion and activation of the portal compartment

Amniotic membrane reduces bile duct ligation-induced liver fibrosis

Recently, stem/progenitor cell transplantation has been proposed as potential treatment for chronic liver disorders as an alternative to organ/hepatocyte transplantation. In this study, based on the fact that amniotic membrane (AM) has long been applied in clinic due to its anti-inflammatory and anti-scarring properties and that AM-derived cells display multipotent differentiation potential and immunomodulatory features, we investigated the potential application of human AM as an innovative therapeutic approach. We evaluated the effects of hAM on biliary-type liver fibrosis induced in rats through bile duct ligation (BDL). A fragment of hAM was applied onto the liver surface after BDL and the rats were euthanised after 2, 4 and 6 weeks. The severity of liver fibrosis was assessed both semi-quantitatively by the Knodell scoring system and quantitatively, by digital image analysis, evaluating liver areas occupied by the ductular reaction (CK 19-positive cells), activated myofibroblasts (alpha-SMA-positive cells) and collagen deposition (Masson's staining). hAM-treated rats displayed significantly lower liver fibrosis with respect to control rats. Indeed, in contrast with BDL rats which showed a progression of fibrosis to cirrhosis from week 4 to week 6, fibrosis in BDL+hAM rats was confined at the portal/periportal area, with collagen deposition at about 50% of levels observed in control rats. Concomitantly, AM application slowed progression of the ductular reaction and significantly reduced the area occupied by myofibroblasts. These findings suggest that human AM patching might counteract fibrosis progression in BDL-injured livers and could represent a new strategy to limit hepatic damage associated with fibrotic degeneratio

An experimental sheep model used to develop an ablation procedure for chronic atrial fibrillation

Atrial fibrillation is the most common form of serious arrhythmia in humans. The therapeutic options offered are medical, surgical, and interventional. The surgical approach is justified in cases of atrial fibrillation already subjected to cardiac surgery for an associated organic heart disease such as a valvular or ischemic disease. A minimally invasive surgical approach is needed to extend the possibility of surgical treatment to patients with lone atrial fibrillation and those who cannot be treated by interventional procedures. This study aimed to use sheep as an experimental model in developing a minimally invasive surgical procedure for chronic atrial fibrillation therapy in humans. Methods: The investigation was conducted with 20 animals using a video-assisted thoracoscopic approach, in which a flexible microwave energy ablating probe was positioned on the epicardial surface encircling the pulmonary veins. Results: In 10 of the 20 animals, it was possible to encircle the pulmonary veins using the thoracoscopic approach in less than 3 h without major complications. Conclusion: The epicardial ablation procedure using the thoracoscopic approach is feasible, safe, and reproducible

Application of human amniotic membrane on rat liver following left hepatectomy : evaluation of liver reaction

Over past decades, the numerous unique characteristics of human amniotic membrane (hAM), such as its anti-inflammatory and antifibrotic properties, justified the frequent use of this material in human reparative surgery and experimental animal disease models. In order to investigate the potential of amniotic membrane to promote hepatic regeneration, we applied the membrane to the external surface of hepatectomized rat livers and assessed hepatocyte proliferation rate and tissue reaction at 1, 3, 7 and 14 days after surgery. Clinical and histopathological data were collected and compared with hepatectomized control rats which received no hAM transplantation and were sacrificed at the same intervals. In both control and hAM-transplanted animals, a rapid rise in mitotic activity was first observed near the resection, followed by a higher peak in mitoses at day 3 in distant areas. The number of binucleated cells, which decreased after partial hepatectomy, increased during liver regeneration, and this was observed more so in hAM transplanted animals. In this group, at day 7, hAM was adherent to the liver capsule in association with interposed palisades of tightly packed fibroblast-like cells. Discrete areas of partial resorption of hAM were observed at day 14. The parenchyma did not show any morphologically appreciable signs of degeneration or inflammatory infiltration in hAM-transplanted animals. Our data suggest that application of hAM membrane to the surface of resected rat livers does not impede normal recovery and actually induces a slight improvement in hepatocyte proliferation without any evident signs of rejection against xenogeneic human transplanted membran

Tough bioactive glasses for implants : experimental study on rabbits as substitute of bone in orthopaedic surgery

This study is a first step to evaluate the properties of the new bioactive glass Crystal Bio Tech both as a bulk and a macroporous material. Both types of glass have been used to repair a 10 mm defect in six rabbit limbs and the implants have been examined for different follow-up periods (3-9 weeks). The results of the radiological and histological evaluation have been compared and are fairly encouraging. In particular, the macroporous glass exhibits good osteoinduction and osteointegration characteristics, and good osteoconduction properties

Laparoscopic cystectomy : an experimental model of urinary diversion

During our experimental trial we achieved laparoscopic cistectomies with urinary diversion to prove our manual capability with the reconstructive surgery. We executed, on male pigs, 10 cistectomies with urinary diversion using laparoscopic technique. We performed 5 ureterocutaneostomies on 5 pigs and, in the other ones, 5 ureterosigmoidostomies. During UCS the pigs laid in lateral position, and during USS in supine position. The average time of the operation is going to reduce in consideration of the overcoming of the initial techno-instrumental difficulties and is 60 minutes for cistectomy, 30 minutes for ureterocutaneostomy and 120 minutes for ureterosigmoidostomy

Laparoscopic nephrectomy

Laparoscopic nephrectomy is a new procedure in which the entire kidney is removed introducing it in an Endopouch and, after morcellation pulled out through a 12 mm port. After an initial experimental experience, in our Institute we have performed one laparoscopic nephrectomy for left pyelonephritic kidney and ureteral reflux. The operation required the positioning of 5 trocars and 4 hours for its execution. The discharge of the patient was possible four days after