Long-term effects of human amniotic membrane in a rat model of biliary fibrosis

Liver fibrosis is the most common outcome of chronic liver diseases, and its progression to cirrhosis can only be effectively treated with liver transplantation. The amniotic membrane (AM) has been studied as an alternative therapy for fibrosis diseases mainly for its favorable properties, including anti-inflammatory, anti-scaring and immunomodulatory properties. It was recently demonstrated that the AM reduces the progression of biliary fibrosis to its advanced stage, cirrhosis, when applied on the liver for 6 weeks after fibrosis induction. Here, we investigated the effects of AM on rat fibrotic liver, during a prolonged period of time. Fibrosis was induced by bile duct ligation (BDL), and at the same time, a fragment of AM was applied around the liver. After 1, 3, 6, and 9 weeks, the degree of fibrosis was assessed by qualitative Knodell scoring, and by quantitative image analysis to quantify the area of collagen deposition in hepatic tissue. While fibrosis progressed rapidly in untreated BDL animals, leading to cirrhosis within 6 weeks, AM-treated livers showed confined fibrosis at the periportal area with few and thin fibrotic septa, but without cirrhosis. In addition, collagen deposition was reduced to about 36 and 55% of levels observed in BDL at 6 and 9 weeks after BDL, respectively, which shows that the longer the period of AM application, the lower the collagen deposition. These results suggested that AM applied as a patch onto the liver surface for longer periods attenuated the severity of biliary fibrosis and protected against liver degeneration caused by excessive collagen deposition.

Photoacoustic monitoring of the absorption of isotonic saline solution by human mucus

Viscosity and elasticity are the fundamental rheologic properties of respiratory mucus, and are important determinants of transportability of mucus in the mucociliary system. One technique that permits to monitor indirectly the rheologic properties of any sample is the photoacoustic technique. Using that technique, the absorption of isotonic saline solution by human mucus was monitored. The mucus was obtained from 11 volunteers, divided into two groups: five volunteers presenting pneumology symptoms (group I) and six healthy volunteers (group II). The photoacoustic signal of the mucus absorbing the saline solution was monitored as function of time, with measurements being performed each 10 min, up to 120 min. The resulting curves were fitted to sigmoidal curves to simulate the evolution on time of the photoacoustic signal. A characteristic time for the half saturation of the absorption process was obtained. For group I the time obtained was 23.3+/-5.3 min and for group II the time obtained was 55.0+/-7.7 min, both means being significantly different (Student t-test, p<0.05). This result supports the empirical practice of treating individuals presenting symptoms of airway obstruction with about 30 min of inhalations of isotonic saline solution vapor for the clearance of the airways.