Electron microscopy of rejected human liver allografts

Recognition by biopsy of liver allograft rejection has been less successful than diagnosis of rejection of cardiac and kidney allografts. In a study of 138 failed liver allografts, we recognized damage to small interlobular bile ducts by lymphocytes as the most useful indicator of the presence of rejection. This is a report of the electron microscopic features of three patients with unequivocal allograft rejection. Lymphocytes and occasional granulocytes penetrated the epithelia of interlobular bile ducts. Ducts with diameters of 30 to 60 microM were preferentially affected but ducts up to 120 microM were also occasionally involved. Point contacts between infiltrating inflammatory cells and bile duct epithelial cells were observed occasionally. Degenerative changes of bile duct epithelial cells were conspicuous and involved nuclei and cellular organelles. Degeneration was often accompanied by aggregation of dense bundles of filaments in the cytoplasm. In severely affected ducts, epithelial cell disintegration was noted. In all involved bile ducts, the basement membrane was markedly thickened. Hepatocytes were well-preserved but contained lipid vacuoles, pigment granules, and blunted canalicular microvilli. The similarity between these observations and those seen in primary biliary cirrhosis and chronic graft-versus-host disease is striking.

Characterization of a primary bile ductular cell culture from the livers of rats during extrahepatic cholestasis

The establishment of novel bile ductular cell cultures was accomplished with the use of explants of a hyperplastic bile ductular tissue preparation obtained from rat livers at 10 to 15 weeks after bile duct ligation or a bile ductular cell fraction isolated from this tissue preparation by a procedure involving Percoll density gradient centrifugation. Observations made on these primary explant and monolayer bile ductular cell cultures were limited to the first 3 days of culture where the morphologic features of the bile ductular epithelium remained fairly well preserved, while fibroblast contamination was found to be very low. These cultured cells also retained over this period a high specific activity for the bile ductular cell marker enzyme gamma-glutamyl transpeptidase, as well as possessed measurable but decreasing specific activities for leucine aminopeptidase and alkaline phosphatase. Karyotypic analysis of the cultured monolayer cells further showed them to be diploid. In addition, preliminary transplantation studies demonstrated the presence of well-differentiated bile ductular-like structures following inoculation of the freshly isolated bile ductular cell fraction into the interscapular fat pads of recipient rats.

The intrahepatic biliary epithelium in the guinea pig: is hepatic artery blood flow essential in maintaining its function and structure?

To determine whether hepatic artery blood flow is essential in maintaining the function and structure of bile ductules/ducts, the acute effects of hepatic artery ligation on bile secretion and hepatic ultrastructure were examined in anesthetized, bile duct-cannulated guinea pigs. Sixty minutes after hepatic artery ligation, spontaneous bile flow (5.08 +/- 0.4 microliter per min per gm liver) was virtually the same as that before hepatic artery ligation (5.31 +/- 0.3 microliter per min per gm), as were the choleretic effects of 10 CU per kg per 30 min secretin (7.14 +/- 0.9 vs. 7.21 +/- 0.9 microliter per min per gm), 300 micrograms per kg per 30 min glucagon (6.72 +/- 0.9 vs. 6.59 +/- 0.8 microliter per min per gm) and 60 mumoles per kg per 30 min glycochenodeoxycholate (6.43 +/- 0.6 vs. 6.45 +/- 0.6 microliter per min per gm). The failure of hepatic artery ligation to affect bile secretory function could not be attributed to the existence of collateral arterial blood flow to the liver. First of all, hepatic artery ligation resulted in diminishing significantly hepatic venous, but not portal, oxygen content. More importantly, in isolated guinea pig livers, perfused through the portal vein alone, secretin, glucagon and glycochenodeoxycholate produced changes in bile flow and composition similar to those seen in vivo. Electron microscopy showed no major ultrastructural changes of hepatic parenchyma and biliary epithelium 2 hr after hepatic artery ligation, or 2 hr after perfusing the liver through the portal vein alone save for some portal edema in the latter instance.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary sclerosing cholangitis. Light and electron microscopy of hepatic tissue in two cases

In an 18 year-old woman presenting with an intra- and extrahepatic form of sclerosing cholangitis needle biopsy of the liver revealed, in addition to a conspicuous proliferation of biliary ductules and mild inflammatory infiltrations of the portal tract, piece-meal necroses and focal intralobular inflammatory changes. In the second case - a 49-year-old man - presenting with an extrahepatic location of stenoses there were infrequent proliferating biliary ductules in the enlarged fibrotic portal tracts. Ultrastructural investigations revealed in both patients adverse regressive changes in the epithelium of proliferating biliary ductules, seen as microvillous damage on the luminal surface, dilation of the endoplasmic reticulum and mitochondrial swelling; in the second patient there was, moreover, electrondense material in epithelial cytoplasm, probably corresponding to bile components. In the first patient predominated among ultrastructural changes increase of cytoskeletal filaments in some epithelia and pronounced reduplication of the basement membranes of small biliary ducts. These "cholestatic" modifications, expressed in different form in the two patients, were accompanied by dilatation and damage, sometimes total disappearance of microvilli of biliary canaliculi.

Hilar biliary plexus in human liver. A comparative study of the intrahepatic bile ducts in man and animals

A comparative study of the hepatic bile ducts of man and laboratory animals was made by means of scanning electron microscopy of biliary tract casts. In man, the large intrahepatic bile ducts at the hilum have many irregular side branches and pouches which are all situated in one plane corresponding anatomically to the transverse fissure (porta hepatis). At the bifurcation, some of the side branches from two or three bile ducts communicate with each other. The anastomosing plexus so formed provides communications between the main bile ducts. Bile ducts of the rhesus monkey show a similar but less well developed structure. In the pig, many pouches are observed around not only large but also small bile ducts. No such structures are observed in dog, guinea pig, or rabbit bile ducts. These irregular side branches and pouches correspond to the "vasa aberrantia" and "parietal sacculi" described by L. S. Beale (The Liver. Lecture on the Principles and Practice of Medicine, p 47. London, Churchill, 1889), and they may store and modify bile. The plexus described in man in this report may provide an anatomical basis for incomplete biliary obstruction without cholestasis. A role in biliary atresia and in Caroli's disease is also raised.

[Ultrastructural findings in intrahepatic bile ducts in primary biliary cirrhosis]

A lesion of small bile ducts wall in 6 women suffering from primary biliary cirrhosis (stage II, III, IV) included unspecific and progressive epithelial changes (increase of cytoskeleton, filaments, many phagosomes, basement membrane reduplication). Besides in stage II of the disease and in one case of cirrhosis, there were dense deposits in widened basement membrane and periductal macrophages which reminded of the bile. Some biliary canaliculi were dilated in all the cases and their microvilli were partly lost or swollen.

A monomeric methyl and hydroxypropyl methacrylate injection medium and its utility in casting blood capillaries and liver bile canaliculi for scanning electron microscopy

A mixture of 50-60% monomeric methyl methacrylate and 40-50% monomeric 2-hydroxypropyl methacrylate was supplemented with 1.5% benzoyl peroxide (catalyst) and 1.5% N,N-dimethylaniline (accelerator) and injected into glutaraldehyde-perfusion fixed rat hypophyseal and other endocrine organ blood vessels and biliary tracts. This injection medium rapidly polymerized at room temperature and did not require partial polymerization prior to injection. Good casts of blood vessels, including the hypophyseal capillaries, were obtained for scanning electron microscopy. The monomeric methacrylate medium possesses a great advantage over previous ones, as its fluidity enables the casting of very fine vessels such as bile canaliculi. In the case of non-fixed tissues, the monomeric methacrylate medium should be injected carefully, as it is toxic and destructive to the vessels.

A hitherto unrecognized bile ductular plexus in normal rat liver

The three-dimensional arrangement of intrahepatic bile ducts was studied by scanning electron microscopy of biliary tract casts. Scanning electron microscopy of biliary casts revealed a complex of portal bile ductular channels. In the rabbit, it is focal and branching whereas in the rat, a plexus comprised of widespread and richly anastomosing network of tubules, 20 to 30 micron in diameter, is present. This plexus was prominent in the large portal tracts and was located at the border of the portal tracts and liver parenchyma. This biliary plexus may play a role in modifying original canalicular bile secreted by hepatocytes.

Structural hepatic changes associated with cyanamide treatment: cholangiolar proliferation, fibrosis and cirrhosis

The authors present the clinical and histological findings in a series of 42 liver biopsies from 39 chronic alcoholics treated with cyanamide as aversion therapy. All biopsies displayed characteristic cytoplasmic inclusions in the liver-cells. Fibrosis and disruption of the parenchymal-connective tissue interface were observed in all cases. According to the severity and extension of fibrosis, three stages could be depicted: Stage I. Periportal activity cholangiolar type (ACT), which is defined by cholangiolar proliferation, fibroblastic activation and inflammatory infiltrate, which together cause a blurred appearance of the parenchymal-connective tissue junction. It is the elementary lesion and was observed alone in 26 biopsies. Stage II. Portal-to-portal linkage. It was observed in 10 biopsies, all of which also showed periportal ACT. Three of these came from patients with two biopsies in which transition from stage I (first biopsy) to stage II (second biopsy) was observed. Stage III. Nodular parenchymal regeneration, associated with changes observed in stage I and II. It was found in six patients. The histological picture resembles the biliary type of cirrhosis. There is a clear-cut correlation between the length of treatment and the stage of the hepatic lesion.

The origin of intrahepatic bile duct cells in the mouse

The origin of the intrahepatic bile ducts in the embryonic mouse liver was investigated. At 12.5 and 13.5 gestation days in the C3H/Tw strain mouse, the liver parenchyma contains morphologically and histochemically homogeneous immature hepatocytes but not bile duct cells. When the liver fragments were cultured in the testis, immature hepatocytes differentiated into large hepatocytes for the most part and also into bile duct cells. In contrast, when the similar liver fragments were cultured under the skin of newborn mice, bile duct cells differentiated much earlier in all transplants than those cultured in the testis. These bile duct cells were considered to be the intrahepatic bile duct cells, since they did not form biliary glands but possessed a basal lamina and histochemical characteristics of intrahepatic bile duct cells of the normal liver. The origin of the endodermal epithelial cells in the mouse liver is discussed with special attention to the differentiation of the intrahepatic bile duct cells from the immature hepatocytes.

Electron microscopic examination of congenital cytomegalovirus hepatitis

The electron microscopic features of cytomegalovirus hepatitis in the liver biopsy of a three-week-old infant were studied. The liver cells did not contain virus, but severe alterations similar to virus hepatitis were observed. In the bile duct cells, nuclear and cytoplasmic virus inclusions were demonstrated. In the nuclear inclusions virus particles of various degrees of maturity were embedded in dense granular material. The cytoplasm of the infected cells contained vacuoles with mature viruses. The Golgi zone seemed to play an important role in vacuole formation. In another type of infected cell, viruses were lying free in the cytoplasm and passed into the lumen of the bile ducts. It is concluded that viruses are eliminimated by the bile. Based on this electron microscopical observations, the examination of duodenal fluid is recommended as a new diagnostic procedure for demonstrating viruses.

Ultrastructural changes of intrahepatic bile ductules in griseofulvin fed mice

Intrahepatic bile ductules in male Swiss Webster mice, fed a diet containing 2.5 percent griseofulvin (GF), showed marked hypertrophy and hyperplasia within two weeks. Thereafter, this reaction gradually increased in prominence until nine weeks. Cytoplasmic acid phosphatase and succinic dehydrogenase deposits were more prominent and abundant after 12 to 14 weeks. Ultrastructural changes in ductular epithelial cells included enlargement of nuclei and nucleoli and increased abundance of cytoplasmic rough surfaced endoplasmic reticulum (RER), ribosomes and mitochondria until nine to 12 weeks. At this interval, duct lumina appeared widely dilated with small clumps of electron dense material at the periphery adjoining apical cell membranes with severely flattened or absent microvilli. Electron dense needle-like crystals resembling protoporphyrin were clustered centrally in the lumina. After twelve weeks occasional mitochondria were markedly swollen and contained vacuolated areas. Numerous multivesicular bodies were noted. Mallory bodies were seen in a few duct cells. The spectrum of duct cell changes just noted gives further evidence of extensive liver injury after GF feeding. These changes, in addition to diverse hepatocyte alterations previously reported, constitute morphologic features of GF induced murine porphyria, also common to human porphyria and human alcoholic liver disease.

Ultrastructural changes in the bile canaliculi and the lateral surfaces of rat hepatocytes during restorative proliferation

Ultrastructural changes in the bile canaliculi and the lateral surfaces of rat hepatocytes during regeneration following a two-third partial hepatectomy were studied by transmission and scanning electron microscopy. A marked increase in microvilli, widening of the intercellular spaces, and invagination and indentation of cytoplasmic membranes were seen in the lateral surfaces of hepatocytes during the early period after the operation. The density of the microvilli on the lateral surfaces gradually decreased and intercellular spaces returned to normal within 24 h, whereas the bile canaliculi revealed dilatation and tortuosity with elongation of microvilli. Hepatocytes during mitosis became rounded and showed dispersed microvilli on the sinusoidal surface. The bile canaliculi of mitotic hepatocytes were continuous with those of adjacent hepatocytes. On the 2nd or 3rd day posthepatectomy, hepatic plates became more than one-cell thick and hepatocytes showed occasional acinar arrangements around the dilated bile canalicular lumina. These features gradually returned to normal by one week after the operation. This study revealed unique sequential changes in the bile canaliculi and the lateral surfaces of hepatocytes during regeneration after partial hepatectomy.

Detection of mitochondria in bile canaliculi in early stage primary biliary cirrhosis cases

Biopsy specimens of liver obtained from patients with early stages of primary biliary cirrhosis were examined by electron microscopy with special attention being paid to changes in bile canaliculi, as well as bile ducts and hepatocytes. Ultrastructural alterations of hepatocytes were minimal and non-specific. In bile canaliculi mitochondria were noted to be normal or slightly lack uniformity. These findings varied according to each case. This alteration was strongly considered to be specific in early stage primary biliary cirrhosis cases.

Ultrastructure of liver cell and bile duct carcinomas

The primary concerns of the surgical pathologist examining a biopsy specimen are whether a particular neoplasm is originating within the liver or is metastatic and, if a primary, whether differentiation is toward liver cells or bile ducts. The present study was undertaken in the hopes of providing a broader concept of the ultrastructural spectrum of liver cell carcinoma (LCC) and a more precise understanding of the changes occurring in these neoplasms with dedifferentiation. The 20 liver cell carcinomas, 13 bile duct carcinomas (BDC), and 3 hepatoblastomas were studied ultrastructurally and the findings correlated with light microscopic sections stained by hematoxylin-eosin and the periodic acid-Schiff procedure with and without prior diastase digestion. Immunocytochemical staining for alpha 1-antitrypsin was carried out on selected tumors. Ultrastructural study can be useful in the distinction of LCC from BDC in the minority of cases in which this is difficult by light microscopy. While true mixed tumors appear to be uncommon, duct formation can be simulated by LCC cells. The extent to which electron microscopy will enable the pathologist to separate metastatic neoplasms in the liver from primary liver cell tumors depends on the relative ultrastructural features. Assessment of the value of electron microscopy as an aid to light microscopy in the histologic grading of LCC and BDC will require further study.

Primary cultures of rat hepatocytes as a model system of canalicular development, biliary secretion, and intrahepatic cholestasis. IV. Disintegration of bile canaliculi and disturbance of tight junction formation caused by vinblastine

Treatment of cultured hepatocytes with vinblastine or colchicine caused striking perturbations of the structural organization of the biliary pole and of the junctional complexes. During the early hours of cultivation the reassociation of the bile canaliculi was impaired by the drug, whereas at later times in culture preformed canaliculi were disintegrated to small vesicular remnants lacking microvilli. Vinblastine did not impair tight junction formation per se. However, under the influence of the drug, tight junctional strands associated in an atypic manner perpendicular to the upper surface of the hepatocytes, whereas those strands lining the canaliculi were decomposed to smaller entities and dislocated within the lateral membrane. Concomitantly to the structural disintegration of the biliary pole an accumulation of vesicles in the pericanalicular cytoplasm was noted. As indicated by numerous filipin-induced lesions, they were characterized by a high content of membrane cholesterol. The apical pole and the contiguous membrane on the other hand contained only very few filipin-cholesterol lesions. These findings suggest that antimicrotubular drugs impair the fusion of pericanalicular vesicles with the luminal membranes of the canaliculi, thus interrupting the delivery of membraneous material to the apical pole. In addition, microtubules seem to play an important role in the coordinated development and the structural fixation of the biliary pole of cultured hepatocytes.

Comparison of the effects of basal and methionine-supplemented recovery diets on the liver of ethionine-pretreated rats

Alterations in the liver of rats during ethionine administration and subsequent recovery on basal or methionine-supplemented diets were examined by light and electron microscopy and by the point counting technique. After administration of 1% DL-ethionine diet for 34 days, adult female rats showed a significant decrease (P less than 0.01) in the percentage volume of hepatocytes and a significant increase (P less than 0.002) in the percentage volume of duct cells compared with control animals. When the carcinogen diet was replaced by either basal or methionine-supplemented diet, the percentage volumes of proliferated duct cells fell. The hepatocytes appeared almost normal in the rats on basal recovery diet, whereas those on methionine diet showed extensive fat accumulation in the central hepatocytes. Similar lipid deposition was observed in rats given either methionine plus ethionine diet or basal diet followed by methionine diet as a recovery diet. The percentage volumes of hepatocytes and duct cells in rats transferred to basal recovery diet did not differ significantly from those placed on methionine diet or on methionine plus ethionine diet. Some possible causes of methionine-induced fat deposition are discussed.

Electron microscopic observation of destruction of biliary epithelium in primary biliary cirrhosis

Electron microscopic studies of the intrahepatic biliary tree in 16 patients with primary biliary cirrhosis (PBC) disclosed four types of biliary epithelial injury suggesting cell death in the ducts: 1) coagulative and 2) lytic necrosis without detachment of affected cells from the biliary epithelial layer, and 3) apoptosis and 4) detachment of several adjoining biliary cells from the basement membrane and neighboring biliary cells. Lesions 1), 2) and 3) were also found in livers with extrahepatic cholestasis without bile duct loss, and 1) and 2) were found in PBC livers irrespective of the degree of bile duct loss. 3) was rare and mostly confined to bile ductules, when present. By contrast, 4) was only observed in PBC, especially in livers with a moderate degree of bile duct loss in which extensive bile duct destruction appeared to be progressing. Detached biliary cells in lesion 4) were occasionally in contact with and/or surrounded by migrating lymphocytes with pseudopod formation, suggesting lymphocyte-target cell interactions. It therefore seems possible that epithelial detachment is an important ultrastructural lesion associated with extensive bile duct destruction in PBC livers.

Hepatic parenchymal cells in cystic fibrosis: ultrastructural evidence for abnormal intracellular transport

Few ultrastructural observations of hepatic parenchymal cells in cystic fibrosis (CF) have appeared in the literature. Utilizing a unique opportunity to examine freshly fixed hepatic tissue by transmission electron microscopy, we studied 12 patients dying with CF at Duke Hospital from 1979 to 1981 in order to identify possible abnormalities of intracellular architecture. The major findings include (1) intracellular fatty vacuoles, (2) distended bile ductules and bile ducts containing increased cellular debris, (3) profiles of distended rough endoplasmic reticulum containing material of medium electron density, and (4) membrane-bound deposits of electron-lucent material containing electron-dense cores resembling mucus. We suggest that the material seen within the cytocavitary network reflects a derangement of intracellular transport.

[Ultrastructural findings in the intrahepatic bile ducts in chronic hepatitis B]

All 14 cases of mildly active chronic type B hepatitis (serological diagnosis was confirmed by light microscopy) showed inextensive ultrastructural changes of the epithelium in small bile ducts and proliferating ductules with basement membrane lesion and inflammatory infiltration. Some peripheric bile ducts swelled lacking microvilli ond narrowing their lumina by a dense border. The findings were more frequent in two biopses with substantial periportal fibrosis.