Fig. 3: ARPKD liver tissue has enlarged bile ducts and increased collagen.
From: A human multi-lineage hepatic organoid model for liver fibrosis
Liver sections were prepared from a normal and from two subjects with ARPKD liver disease. a In the H&E (upper) and trichrome-stained liver sections (middle), the marked increase in ECM (blue regions) in ARPKD liver tissue is readily apparent. Scale bars: 500 μm. Bottom panels: Higher power (scale bars, 50 μm) immunofluorescent images of liver sections stained with anti-CK8 and anti-collagen (COL1A) antibodies. CK8 is a marker for both hepatocytes and cholangiocytes. In normal liver, some collagen is deposited around the portal triads; and the inset shows an enlarged view of a portal triad. In ARPKD liver, there is a marked increase in the amount of collagen, which is diffusely distributed throughout the stroma; and the abnormal bile ducts lined by CK8+ cells are readily apparent. b SHG analysis of the collagen fibers in human HOs. (upper) Depth color-coded projections of collagen fibers within day 21 control and ARPKD organoids. Control organoids (left) have a few, isolated regions with relatively thin collagen fibers. ARPKD organoids (right) have a confluent network of thick collagen fibers that extend throughout the entire organoid. (lower) Quantitative comparison of SHG images from ARPKD and control organoids (n = 10 for C1, C2, C3; and for a mixed culture of all three) shows statistically significant increases in total collagen abundance (left), and in the fraction of thick collagen fiber bundles (right, diameter > 6.0 μm). Unpaired t-test results for collagen abundance (C1: ARPKD vs control p < 0.0001, C2: ARPKD vs control p < 0.0001, C3: ARPKD vs control p = 0.0136, Mix: ARPKD vs control p < 0.0001). Unpaired t-test results for fraction of thick collagen fiber bundles (C1: ARPKD vs control p < 0.0001, C2: ARPKD vs control p < 0.0001, C3: ARPKD vs control p = 0.006, Mix: ARPKD vs control p = 0.0003) c SHG analysis of liver tissue obtained from control and two ARPKD patients. In these images, the collagen fibers are blue; DAPI-stained nuclei are magenta; and CK8+ cholangiocytes are green. The amount of fibrous collagen is significantly increased in the ARPKD liver samples (13.3 ± 10.6%, n = 47) vs. normal liver tissue (1.8 ± 2.3%, n = 38). Unpaired t-test results p = 2 × 10−9. Also, the collagen fibers in the ARPKD liver tissue formed thick bundles (right, diameter > 6.0 μm, unpaired t-test ARPKD vs health liver p = 2 × 10−8), which are much larger than the ~1 micron-sized, isolated fibers present in the normal liver tissue (see insets). *p < 0.05, **p < 0.01, ***p < 0.001.
