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Keywords:

  • elderly cadavers;
  • liver fibrosis;
  • perisinusoidal basement membranes;
  • collagen type IV;
  • laminin

ABSTRACT

  1. Top of page
  2. ABSTRACT
  3. MATERIALS and METHODS
  4. RESULTS
  5. DISCUSSION
  6. CONCLUSIONS
  7. ACKNOWLEDGEMENTS
  8. LITERATURE CITED

Liver sinusoids are lined by a fenestrated endothelium that lacks a basement membrane. Formation of perisinusoidal basement membranes beneath the endothelium is an integral feature of capillarization of sinusoids that is a significant pathology found in advanced fibrosis. Liver fibrosis is prevalent in elderly cadavers; however, basement membrane formation in these liver samples has yet to be studied. Collagen type IV and laminin are major basement membrane proteins and their codistribution around sinusoids provides an immunohistochemical marker of basement membrane formation. Here, we examined the intralobular sites of perisinusoidal basement membrane formation in elderly cadaveric livers having various stages of fibrosis. Collagen IV and laminin codistributed in basement membranes of portal and septal ductular and vascular structures, providing a positive control. In the parenchyma, collagen IV immunostaining of sinusoids was panlobular in all stages of fibrosis, and the stain was continuous along the sinusoids. In contrast, laminin was not detected in livers, showing minimal fibrotic change. It was rarely seen in perisinusoidal/pericellular fibrosis, but frequently in septa formation, bridging fibrosis, and cirrhosis. The laminin stain was patchy, occurring principally in sinusoids of periportal and periseptal areas, less commonly in mid-lobular and rarely in centrilobular areas. Consecutive sections revealed that laminin codistributed with collagen IV in these sinusoidal locations, thus marking the sites of perisinusoidal basement membrane formation in aged fibrotic livers. This development is presumably related to aging of the liver and exacerbated by liver injury caused by advanced liver fibrosis, possibly resulting in sinusoidal capillarization. Anat Rec, 296:953–964, 2013. © 2013 Wiley Periodicals, Inc.

The hepatic sinusoids are lined by a fenestrated endothelium and lack an electron microscopically continuous basement membrane that is present in most systemic blood vessels (Mak and Lieber, 1984); thus, liver sinusoids are classified as discontinuous capillaries (Simionescu and Simionescu, 1988). In the human liver, collagen type IV is present in the space of Disse (perisinusoidal space) surrounding the sinusoids not associated with laminin (Hahn et al., 1980), an integral basement membrane glycoprotein found in most basement membranes (Timpl et al., 1979). Other extracellular matrix proteins such as collagen types I and III and fibronectin are also present in smaller amounts in the space (Wells, 2007).

Capillarization of sinusoids is a significant pathology found in advanced stages of liver fibrosis. It was first described by Schaffner and Popper (1963) in human alcoholic cirrhosis and then observed in chronic liver disease of various causes, as well as in a variety of experimental models of fibrosis (Horn et al., 1987; Babbs et al., 1990; Jezequel et al., 1990; Martinez-Hernandez and Martinez, 1991; Nakayama et al., 1991; Bhunchet and Fujieda, 1993; Urashima et al., 1993; Dubuisson et al., 1995; Xu et al., 2003). As noted by electron microscopy, formation of a continuous basement membrane beneath the endothelial cells is a main feature of sinusoidal capillarization. This development, concomitant with the loss of endothelial fenestra, transforms the sinusoids into continuous capillaries. Laminin production is enhanced and its deposition is localized immunohistochemically with collagen IV in the perisinusoidal basement membrane (Jezequel et al., 1990; Nakayama et al., 1991; Dubuisson et al., 1995). These changes, along with increased presence of type I and III collagens and other matrix proteins in the space of Disse, impair the normal exchange of materials in particular macromolecules between sinusoids and hepatocytes (Martinez-Hernandez and Martinez, 1991).

Hepatic fibrosis, including advanced stages of fibrosis, is prevalent in elderly cadavers with diverse causes of death (Mak et al., 2012a), but the intralobular anatomical sites of perisinusoidal basement membrane formation in these samples have yet to be studied. As collagen type IV and laminin are major proteins of basement membranes, their codistribution in the sinusoidal lining provides an immunohistochemical marker of perisinusoidal basement membrane formation (Jezequel et al., 1990; Nakayama et al., 1991; Dubuisson et al., 1995). Accordingly, the aims of this study were to assess by immunolight microscopy the distribution of collagen IV and laminin in the liver lobules of elderly cadavers, showing progressive fibrotic changes, and to determine the codistribution of these proteins in the sinusoids that, thus, marks the anatomical sites of perisinusoidal basement membrane formation in hepatic fibrosis.

MATERIALS and METHODS

  1. Top of page
  2. ABSTRACT
  3. MATERIALS and METHODS
  4. RESULTS
  5. DISCUSSION
  6. CONCLUSIONS
  7. ACKNOWLEDGEMENTS
  8. LITERATURE CITED

Specimens

Paraffin-embedded liver tissue of embalmed elderly cadavers from our previous study provided the source of specimens in the present investigation (Mak et al., 2012a). The mean age of these people was 82.1 ± 10.4 years. As previously reported (Mak et al., 2012a), embalmed cadaveric livers presented variable tissue preservation histologically (good, fair, or poor), evaluated by hematoxylin and eosin staining. Based on the combined fibrotic changes and tissue preservation, we selected 4 livers showing minimal fibrosis, 5 perisinusoidal/pericellular fibrosis (with no accompanying septal fibrosis), 11 septa formation, 11 bridging fibrosis, and 3 cirrhotic livers that also disclosed good or at least fair tissue preservation. The latter three stages of fibrosis were considered advanced fibrosis in this study, which also had variable degrees of perisinusoidal/pericellular fibrosis in the liver parenchyma. Fibrosis was determined using Sirius red stain for collagens.

Immunohistochemistry

A mouse anticollagen type IV antibody and a mouse antilaminin antibody were purchased from Sigma-Aldrich Chemical (St. Louis, MO). Collagen IV antibody was used at a dilution of 1:2,000–4,000 and laminin antibody at 1:500 in 1% bovine serum albumin in phosphate-buffered saline. Serial paraffin liver sections (∼1 × 1 cm2) were cut at a thickness of 5 µm. Consecutive liver sections were immunostained for collagen IV and laminin: one section was exposed to the collagen type IV antibody and one to the laminin antibody. For laminin, liver sections were first treated with 0.4% pepsin (Sigma-Aldrich; Catalog # R2283) at 38°C for 15 min and then with the antibody. After the peroxide block, sections were incubated with the respective antibodies at 4°C for 20 hr. The secondary antibodies were antimouse horseradish peroxidase polymer and used in accordance with the manufacturer's instruction (Dako Envision System, Carpinteria, CA). Color reaction was revealed with the chromogen 3,3′-diaminobenzidine tetrahydrochloride. Nuclei were counterstained with hematoxylin.

The sensitivity of laminin and collagen IV detection by the antibodies to laminin and collagen IV, respectively, was verified by a positive staining of basement membranes of human kidney sections fixed with formalin. Sections that were not treated with pepsin did not show laminin staining of basement membranes. Both antibodies did not stain interstitial fibrillar collagens.

To determine codistribution of laminin and collagen type IV around sinusoids, consecutive liver sections stained for these proteins were studied under a Nikon Eclipse 50i microscope (Nikon Instruments, Melville, NY). Areas of interests were photographed at various magnifications and analyzed for the concurrency of laminin and collagen IV immunoreactivity in the sinusoidal lining that, thus, provided an immunohistochemical marker of perisinusoidal basement membrane formation (vide supra). Similarly, the immunostaining of biliary and vascular structures in portal tracts for laminin and collagen IV was examined and the localization of these proteins in basement membranes served as a positive control.

RESULTS

  1. Top of page
  2. ABSTRACT
  3. MATERIALS and METHODS
  4. RESULTS
  5. DISCUSSION
  6. CONCLUSIONS
  7. ACKNOWLEDGEMENTS
  8. LITERATURE CITED

The staining reactions of portal tracts, central veins, and fibrous septa for collagen IV and laminin were first assessed, followed by the staining of sinusoids in the liver parenchyma.

Portal Tracts

The basement membranes surrounding bile ducts and ductules and around the lumens of portal venules, arterioles, and lymphatics in the portal tracts stained distinctly with the antibodies to collagen type IV and laminin (Fig. 1A,B). Serial sections revealed that the immunostains for collagen IV and laminin localized to the same ductular and vascular basement membranes, consistent with colocalization of these proteins in basement membranes. Collagen IV and laminin staining was also visible in the basal lamina of nerve axons and smooth muscles of vessel walls in larger-sized portal tracts (data not shown). The stroma of portal tracts disclosed collagen IV-positive fibrillar structures but scarcely laminin-stained fibrils.

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Figure 1. Immunostaining for collagen IV and laminin in portal tracts. The boxed areas of these consecutive sections (A) and (B) are shown at a higher magnification in the right panels. The basement membranes (arrows) surrounding the bile ductules and around the lumens of portal venules, arterioles, and capillaries show distinct stainings with the antibodies to collagen IV and laminin. Note the collagen IV-immunopositive fibrillar structures in the portal matrix.

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Central Veins

In both fibrotic and nonfibrotic veins, the basement membranes around the vein lumens showed positive staining for collagen IV (Fig. 2A,C). Also, the fibrillar structures in the thickened rim of the vein were immunopositive for collagen IV. In contrast, laminin was not detected in central veins, whether fibrotic or nonfibrotic veins (Fig. 2B,D). These results suggest that hepatic central veins lack a continuous basement membrane that is normally associated with systemic vascular endothelium.

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Figure 2. Immunostaining for collagen IV and laminin in central veins. The serially sectioned veins in (A) and (B) show features of central vein fibrosis with a thickened wall containing copious collagen fibers that appear grayish after hematoxylin counterstaining. (C) and (D) Serial sections showing a nonfibrotic vein with a thin rim. Collagen IV immunostain is visible in the basement membranes (arrow) around the lumens of the fibrotic vein as well as the nonfibrotic vein, whereas laminin is not detectable in the corresponding veins. Also, note the collagen IV-immunopositive fibrillar structures in the thickened wall of the fibrotic vein in (A).

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Fibrous Septa

Septa formation and bridging fibrosis are considered advanced hepatic fibrosis (Popper and Udenfriend, 1970; Chevallier et al., 1994). In the liver of elderly cadavers, septa extensions from fibrotic portal tracts were more prevalent than septa extending from fibrotic central veins (Mak et al., 2012a). As shown in Fig. 3, the septal matrix contained variable numbers of ductular and vascular structures that were outlined by a collagen IV-or laminin-immunopositive basement membrane (Fig. 3). In the thicker septa, the ductules were typical with a visible lumen and the venules had a dilated lumen. The thinner septa, by comparison, contained atypical ductules composed of a flattened epithelium with no visible lumen, and the vessels showed features of capillaries, lacking a muscular wall. In the matrix of larger septa, collagen IV-positive fibrils, but not laminin, could be seen. Also, septal mesenchymal cells resembling myofibroblasts demonstrating immunostaining for laminin or collagen IV were present.

image

Figure 3. A: Septum of moderate width, showing the presence of ductules (black arrows) and blood vessels (red arrows) as outlined by collagen IV-positive basement membranes. B: Consecutive section of (A), showing the corresponding ductules and vessels stained positively for laminin. The septal matrix displays collagen IV immunoreactivity but not laminin. Note the cellularity of the septum, which is more evident in (B). C: Several septal cells with fusiform shape resembling myofibroblasts (arrow) and containing laminin immune deposits in the cytoplasm are shown.

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Parenchyma and Sinusoids

Collagen type IV

In elderly cadavers, sinusoidal expression of collagen IV was present in the liver, showing the various stages of fibrosis from minimal changes to cirrhosis (Table 1). Collagen IV immunostaining was panlobular in distribution and the stain was continuous in fashion along the sinusoids (Fig. 4A). Variations in the staining intensity were noted from lobules to lobules, which were unrelated to the stages of fibrosis. It is worth noting that there was a marked increase of collagen IV immunostain in parenchymal foci, showing marked perisinusoidal/pericellular fibrotic changes (Fig. 4B), in parallel with the deposition of type I and III collagens as reported earlier (Mak et al., 2012b). Perisinusoidal hepatic stellate cells throughout the lobules were observed to contain collagen IV immune deposits (Fig. 4C), in accordance with the production of collagen IV.

Table 1. Incidence of collagen type IV and laminin immunostaining of hepatic sinusoids in elderly cadavers
 Collagen IVLaminin
Fibrotic stages(Number of cases positive/livers)
  1. a

    Fibrosis with no accompanying septal fibrosis.

  2. b

    Advanced fibrosis with variable degrees of perisinusoidal/pericellular fibrosis.

  3. c

    The incidence between septa formation and bridging fibrosis is not statistically different by Chi-square test, P = 0.1696.

  4. Collagen IV is present in sinusoids in all stages of liver fibrosis. Laminin expression becomes detectable in livers with advanced fibrosis.

Minimal fibrotic change4/40/4
Perisinusoidal/pericellular fibrosisa5/51/5
Septa formationb11/119/11c
Bridging fibrosisb11/116/11c
Cirrhosisb3/33/3
image

Figure 4. A: Collagen type IV immunostaining of liver lobules. Collagen IV stain is seen throughout the lobules and the stain is uniformly continuous along the sinusoids. Note the characteristic stellate borders of the fibrotic portal tract (PT). B: This image illustrates focal increase of collagen IV immunoreactivity in a perisinusoidal /pericellular fibrotic lesion (arrow). C: Perisinusoidal hepatic stellate cells (arrows), demonstrating cytoplasmic localization of collagen IV immunostain. Note the small lipid droplets in the cell cytoplasm and the cell processes along the sinusoidal lining, typical features of hepatic stellate cells. CV, central vein.

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Laminin

Expression of laminin was not found in the parenchyma of elderly cadaveric livers, showing minimal fibrotic changes, and it was present only in one case of perisinusoidal/pericellular fibrosis in the absence of septal fibrosis (Table 1). However, laminin was detectable in advanced fibrosis of septa formation, bridging fibrosis, and cirrhosis. Compared with collagen IV, the laminin immune deposits in the sinusoids were patchy and speckled, occurring principally in the periportal parenchyma close by enlarged, fibrotic portal tracts, and in the periseptal parenchyma (Fig. 5). Although a few foci of laminin-immunopositive sinusoids were observed in the mid-lobular areas (Fig. 6A), sometimes in association with parenchymal fibrosis, they were rarely seen in the centrilobular regions. Strikingly, sinusoids labeled with laminin stain were found aggregated in the parenchyma along the path of septa formation (Fig. 6B), and their presence was increased in the parenchyma adjacent to the front of expanding septa (Fig. 6C). As shown in Fig. 6D, laminin was detected in perisinusoidal hepatic stellate cells, reflecting the cellular source of laminin production.

image

Figure 5. Laminin immunostaining of liver sinusoids in periportal (A) and periseptal (B) parenchyma. The patchy, speckled sinusoidal laminin staining (brown color), and the localized distribution of laminin-positive sinusoids in the periportal area and periseptal parenchyma contrast strikingly to the diffuse distribution of collagen IV-positive sinusoids in the lobules as shown in Fig. 4. PT, portal tract; ST, septum.

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image

Figure 6. A: Mid-lobular area showing focal localization of sinusoids stained with the laminin antibody. The laminin stain in the sinusodal lining is patchy and discontinuous (brown color). Macrovesicular and microvesicular fats are present in hepatocytes. B: This image shows laminin-immunopositive sinusoids aligned along the path of a developing septum (brown color). A single sinusoid, showing laminin stain is also visible in the parenchyma (arrow). C: Growing front of an expanding septum (ST), showing increased presence of laminin-positive sinusoids (arrows) at the septal–parenchymal border. D: Perisinusoidal hepatic stellate cell (arrow) demonstrating laminin staining in the cell body and the cell process. The cell is located at the portal–parenchymal border. PT, portal tract stroma.

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Microscopic Fibrous Scars

Fibrous scars, measured <100 µm across, were observed in fibrotic livers of elderly cadavers with septa formation and bridging fibrosis, particularly in the mid-lobular areas. In the matrix of the scars, microvessels were observed, revealing immunostaining for laminin or collagen IV (Fig. 7). These vessels lacked a muscular wall and had the diameter of the capillary, which may represent capillarized sinusoids. They were surrounded by a matrix of fibrillar structures that stained positively for collagen IV but not for laminin.

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Figure 7. Microscopic fibrous scars in liver lobular parenchyma. The scars, measured <100 µm across, are found in the mid-lobular area and sometimes in the centrilobular area. A and C: Laminin immunostaining is seen in association with microvessels (brown color) in the matrix of the scars (*). B and D: Corresponding consecutive sections that stained for collagen IV. Arrows mark the vessels that disclosed a concurrency of collagen IV and laminin stains. Note the lightly stained collagen IV fibrils in the scar matrix. E: Another image of micro-scar (*), showing associated laminin-positive microvessels (brown color). The scar matrix lacks laminin stain, but nonetheless stained strongly for collagen IV shown in (F).

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Figure 8. Codistribution of laminin and collagen IV in hepatic sinusoids. A and B: Consecutive sections showing the periportal area of a liver lobule, and (C) and (D) are consecutive sections presenting periportal fields around a portal tract. The sinusoidal laminin immunostaining is patchy and focal (A) and (C), whereas collagen IV stain is continuous around the sinusoids and is diffuse in the liver lobules (B) and (D). Arrows mark the sinusoids that stained positively for laminin are also immunopositive for collagen IV. Note that many collagen IV-stained sinusoids have no corresponding laminin-positive sinusoids. PT, portal tract.

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image

Figure 9. Consecutive sections demonstrating codistribution of laminin and collagen IV in hepatic sinusoids. A and B: Periseptal parenchyma; C and D: Mid-lobular parenchyma. In the respective panels, arrows mark the sinusoids that stained positively for laminin are also immunopositive for collagen IV.

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image

Figure 10. A and B: Lower power view of consecutive sections, showing septa formation and associated immunostaining for laminin and collagen IV. The septum (black arrow), relatively thin, is seen extending from the portal tract (PT) and dissecting the liver parenchyma. A: Laminin immunoreactivity is localized in the parenchyma along the course of the developing septum. Laminin stain is also seen in a location close by the portal tract (blue arrow) and in a small focus (red arrow) of the parenchyma. B: Collagen IV stain is present along the length of the septum and also diffusely in the parenchyma. The boxed areas and structures at the blue arrows in A and B are shown at higher magnification in Fig. 11.

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image

Figure 11. A and B: Boxed area in Fig. 10; C and D: Structures indicated by the blue arrows in Fig. 10. Arrows, in the respective panels, mark the corresponding sinusoids that are immunopositive for both laminin and collagen IV, demonstrating laminin and collagen IV codistribution.

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Codistribution of Laminin and Collagen Type IV in Hepatic Sinusoids

Next, we determined the intralobular sites of perisinusoidal basement membrane formation. To that end, codistribution of laminin and collagen IV was examined using consecutive liver sections (vide supra). On color photographs, laminin-immunopositive sinusoids were matched with sinusoids that showed collagen IV immunostaining. Representative micrographs of consecutive sections illustrating the codistribution of laminin and collagen IV in sinusoids at various intralobular locations of the liver with advanced fibrosis are shown in Figs. 8-11.

DISCUSSION

  1. Top of page
  2. ABSTRACT
  3. MATERIALS and METHODS
  4. RESULTS
  5. DISCUSSION
  6. CONCLUSIONS
  7. ACKNOWLEDGEMENTS
  8. LITERATURE CITED

In this study, we first documented the localization of collagen type IV and laminin in the basement membranes of biliary ductular and vascular structures in the portal tract by immunohistochemistry using antibodies to collagen type IV and laminin. The finding confirmed that collagen IV and laminin are normal constituents of basement membranes, and thus validating their codistribution in the liver sinusoids as an immunohistochemical marker of preisinusoidal basement formation.

Generally, basement membranes are visualized using the electron microscope. However, the cadaveric livers were preserved in embalming solutions and the quality of tissue preservation is not optimal for ultrastructural assessment. Accordingly, we sought to localize perisinusoidal basement membrane formation by determining collagen IV and laminin codistribution using immunolight microscopy, which offers several distinct advantages over electron microscopy. These include: (1) a larger liver section (∼1 × 1 cm2 vs. 1 × 1 mm2 in electron microscopy) with well-oriented liver lobules can be studied, facilitating identification of the anatomical sites of perisinusoidal basement formation within the lobules; (2) the process associated with immuolight microscopy is technically less time consuming; and (3) the cost is less prohibitive.

We determined expression of collagen IV and laminin in the liver parenchyma of elderly cadavers having progressive fibrotic changes. We found a striking difference between the staining patterns of these proteins in the liver lobules. Collagen IV is expressed throughout the liver lobules, whether disclosing minimal fibrotic change or advanced fibrosis, reflecting that the protein is a normal component of the sinusoidal lining, regularly present irrespective of hepatic pathology. The collagen IV immunostain is continuous along the sinusoids, rather than discontinuous. In fact, the panlobular distribution of collagen IV in the elderly cadavers is also a feature occurring in the adult human liver with a near normal histology (unpublished observation), in patients with varying degrees of alcoholic fibrosis, or in experimental hepatic fibrogenesis in rats (Hahn et al., 1980; Jezequel et al., 1990; Nakayama et al., 1991; Dubuisson et al., 1995). It is worth noting that despite the deposition of collagen IV in the sinusoidal lining, a typical basement membrane could not be detected beneath the sinusoidal endothelium by electron microscopy (Hahn et al., 1980).

Compared with collagen IV, laminin is generally not expressed in the liver in the absence of active fibrogenesis, whether of human or experimental animals, except in the portal field (Hahn et al., 1980; Jezequel et al., 1990; Nakayama et al., 1991; Tsutsumi et al., 1993; Dubuissen et al., 1995). Similarly, we found no laminin expression in the lobular parenchyma, showing minimal fibrotic change. There was a case of laminin expression detected in the liver that had perisinusoidal/pericellular fibrosis, but laminin expression became prevalent in advanced fibrosis of septa formation, bridging fibrosis (sometimes designated as precirrhosis), and cirrhosis. The laminin sinusoidal stain is patchy and speckled, which is in striking contrast to the continuous fashion for collagen IV. We also observed that the laminin-immunopositive sinusoids are discretely localized, appearing in the periportal and periseptal parenchyma, along the developing septa, and at the front of expanding fibrous septa, as well as in microscopic fibrous scars. The laminin immunostain in these anatomical locations was found to codistribute with collagen IV, and thus marking the sites of perisinusoidal basement membrane formation within the liver lobules. However, our observations also showed that in the aged cadaveric livers collagen type IV immunoreactivity occurs in many sinusoids that are not accompanied by laminin stain, and thus lacks a codistribution with laminin in a vast region of the liver lobules, particularly in the centrilobular parenchyma. This finding suggests that although many vessels in the liver parenchyma remain sinusoidal, others have become capillarized.

The localization of collagen IV alone in the sinusoidal lining reflects a basement membrane-like structure surrounding the perisinusoidal surface in the liver of aged cadavers. Physiologically, the presence of basement-like material composed of collagen IV in the space of Disse does not appear to present a permeability barrier for metabolic exchange between the sinusoidal circulation and the parenchymal cells. However, the addition of laminin to collagen IV already in the space of Disse will restructure the basement membrane-like material into a continuous basement membrane beneath the endothelium, which likely constitutes a functionally significant filtration barrier for bidirectional exchange of macromolecules between sinusoids and hepatocytes, leading to liver dysfunction in advanced fibrosis (Martinez-Hernandez, 1991) and to disease susceptibility in older people (McLean et al., 2003).

The production of perisinusoidal basement membrane is an integral feature associated with the pathogenesis of capillarization of hepatic sinusoids in advanced fibrogenesis of diverse causes. Therefore, the development of basement membrane might be presumed to result in the formation of capillarized sinusoids in the aged liver. There is no study, to date, specifically looking at the incidence of sinusoidal capillarization in the aging human liver. However, a nearly identical histological lesion, termed pseudocapillarization of sinusoids, has been described in the liver of older people even in the absence of overt fibrosis (McLean et al., 2003; Le Couteur et al., 2008). This pathological process appears to be an age-related change and is indicated by thickening of sinusoidal endothelial cells with reduction in fenestration, sporadic development of basal lamina in the Disse space, and slight perisinusoidal collagenization. Thus, it is possible that the pathogenesis of perisinusoidal basement membrane in this study is also related to aging of the liver and aggravated by advanced fibrosis.

CONCLUSIONS

  1. Top of page
  2. ABSTRACT
  3. MATERIALS and METHODS
  4. RESULTS
  5. DISCUSSION
  6. CONCLUSIONS
  7. ACKNOWLEDGEMENTS
  8. LITERATURE CITED

In conclusion, codistribution of collagen type IV and laminin in sinusoids serves as an immunohistochemical marker of perisinusoidal basement membrane formation in the liver lobules of the elderly cadavers. The development of basement membranes in the space of Disse around the sinusoids will compromise multiple hepatic functions in the elderly cadavers. However, given the focal, rather than diffuse, distribution of the lesion in the liver parenchyma, its impact on hepatic functions may be localized. The pathogenesis of perisinusoidal basement membrane in aged people cadavers is presumably related to aging of the liver and exacerbated by liver injury caused by the development of advanced liver fibrosis, possibly resulting in sinusoidal capillarization.

ACKNOWLEDGEMENTS

  1. Top of page
  2. ABSTRACT
  3. MATERIALS and METHODS
  4. RESULTS
  5. DISCUSSION
  6. CONCLUSIONS
  7. ACKNOWLEDGEMENTS
  8. LITERATURE CITED

Ting-Fang Lee was a recipient of the Postdoctoral Research Abroad Program (NSC 100-2917-1–564-006) of the National Science Council, Taiwan. We wish to acknowledge the support by the Research Fund of the Center for Anatomy and Functional Morphology, Icahn School of Medicine at Mount Sinai, New York.

LITERATURE CITED

  1. Top of page
  2. ABSTRACT
  3. MATERIALS and METHODS
  4. RESULTS
  5. DISCUSSION
  6. CONCLUSIONS
  7. ACKNOWLEDGEMENTS
  8. LITERATURE CITED