Déficit en alpha-1-antitrypsine chez l'enfant

Summary Fourteen liver biopsies from twelve young patients with liver diseases associated with homozygous, PiZZ phenotype, alpha-1-antitrypsin deficiency in their sera were examined by electron microscopy.In all these biopsies characteristic homogeneous material was found in some hepatocytes and corresponded, when observed on adjacent semithin sections by light microscopy, to the deposit stained by periodic acid Schiff reaction. The accumulation in perinuclear spaces resulted in intranuclear invaginations, but the major deposit was located in lumens of the endoplasmic reticulum. The limiting membranes were rough and smooth but the extent of the latter was so large that only this type of reticulum seemed peculiarly involved in the accumulating process.On the contrary, Golgi complexes did not seen obligatorily involved by this process because, when observed, they appeared almost normal even in heavily overloaded liver cells.At least for the PiZZ phenotype, the abnormal substance would be an asialo form of normal alpha-1-antitrypsin. Thus the subject of this study is the morphologic translation of an impairment in the synthesis of a glycoprotein.In the light of data concerning the synthesis of such proteins our findings lead us to suggest:The ultrastructural patterns observed in alpha-1-antitrypsin deficiency cannot give the expected morphologic evidence of the biochemical data which locate the first binding steps of monosaccharide residues in the rough endoplasmic reticulum.The absence of sialic acid could not result from an enzymatic defect primarily located in Golgi complexes but could be secondary to an impairment in the binding of one monosaccharide residue which improves subsequent fixation of sialic acid, in the smooth endoplasmic reticulum.Finally it seems necessary to emphasize that the relationship between the abnormal substance and various important non specific lesions is largely unknown and that we don't know the significance of polymorphous dense bodies observed in ductular cells during the cholestatic period.

     

Alpha-1-antitrypsin deficiency: accumulation or degradation of mutant variants within the hepatic endoplasmic reticulum

Recent molecular and biochemical analyses of several alpha-1-antitrypsin variants suggest that the severe deficiency or complete absence of this protease inhibitor from serum results predominantly from the retention of mutant variants within the hepatic endoplasmic reticulum where they can accumulate or undergo intracellular degradation. Additional studies have demonstrated that the accumulation of the insoluble PiZ variant within this subcellular compartment acts as an etiologic agent for the development of liver disease in transgenic mice.     

Hepatocyte inclusions of δ1-antichymotrypsin in a patient with partial deficiency of δ1-antichymotrypsin and chronic liver disease

We present a case of chronic liver disease with selective and exclusive hepatocyte endoplasmic reticulum storage of alpha 1-antichymotrypsin in the form of granules, detected by specific immunohistochemistry at the light microscopy level and corresponding to material found in dilated endoplasmic reticulum of hepatocytes by electron microscopy. The patient had intermediate deficiency of alpha 1-antichymotrypsin. Thus, the hepatocyte accumulation of alpha 1-antichymotrypsin may indicate the presence of an export block resembling that of a closely-related protein, namely PiZ alpha 1-antitrypsin. It is proposed that hepatocyte storage of alpha 1-antichymotrypsin may be an expression of an inborn error of metabolism bearing the characteristics of endoplasmic reticulum storage diseases such as PiZ alpha 1-antitrypsin deficiency and hereditary hypofibrinogenaemia.     

Liver cirrhosis caused by alpha-1-antitrypsin deficiency

The authors present 2 patients with cirrhosis of the liver associated with alpha-1-antitrypsin deficiency. The patients are two children (brother and sister aged 4 and 13). The manifestation of the disease in these two children was a prolonged neonatal icterus. The symptoms of a decompensated cirrhosis of the liver appeared at the age of 2 and 4 years. There were several attacks of obstructive bronchitis etiologically associated with the same cause. The boy died at the age of four of hepatic coma preceded by several bleedings from esophageal varices. Splenectomy was performed in the girl on account of distinct signs of hyperplenism and two and a half years later mesentericocaval shunt because of the extensive bleeding from esophageal varices and the fundus of the stomach. The diagnosis of alpha-1-antitrypsin deficiency was made on the basis of low values in the serum and on the basis of liver biops? and findings of typical PAS positive inclusions in the endoplasmic reticulum of hepatocytes. The values of A1A parents are also lower. The finding of Pi phenotypification is significant--the SZ phenotype was found in two patients (brother and sister), which is seldom described in patients with cirrhosis of the liver.     

Ultrastructural studies of the hepatocytes after chronic exposure to low levels of halothane.

Adult rats were exposed to 10 ppm or 500 ppm halothane 8 hr/day and 5 days/wk for 8 wk or 4 wk, respectively. In the liver from animals which were exposed to 10 ppm of halothane, the rough endoplasmic reticulum in some hepatocytes accumulated a floccular, electron-dense material which gave the hepatocytes a dense and dark appearance. Increase in the matrical density and C-shaped transformation were observed in the mitochondria of some hepatocytes. In addition to these findings, areas of focal cytoplasmic degradation, dilatation of the bile canaliculi, peribiliary accumulation of lysosomes, and extensive dilatation of the smooth endoplasmic reticulum to form large cytoplasmic vacuoles were also observed in the hepatocytes of animals which had been exposed to 500 ppm halothane. Toxic potential of halothane upon chronic exposure is suggested.     

Hepatocytic PAS-positive diastase-resistance inclusions in the absence of alpha-1-antitrypsin deficiency--high prevalence in alcoholic cirrhosis

The presence of PAS-positive, diastase-resistant inclusions in the cytoplasm of the hepatocytes is characteristic of alpha-1-antitrypsin deficiency. The purpose of this investigation was to determine whether the presence of these inclusions is a specific feature, permitting the recognition of alpha-1-antitrypsin deficiency in patients with liver disease. We examined the liver specimens from 20 patients suffering from alcoholic cirrhosis with the Pi M phenotype, i.e., in whom alpha-1-antitrypsin deficiency was excluded. In seven of these patients, PAS-positive, diastase-resistant inclusions were seen in the hepatocytes; in two patients, these inclusions contained a material antigenically similar to alpha-1-antitrypsin. These inclusions might represent deposits of glycoproteins poorly excreted by the diseased hepatocytes. It is concluded that, in patients with liver disease, the presence of PAS-positive, diastase-resistant inclusions--even containing alpha-1-antitrypsin--in the cytoplasm of the hepatocytes does not permit the hepatic lesions to be ascribed to alpha-1-antitrypsin deficiency.     

Liver disease in infancy: histological features and relationship to alpha-antitrypsin phenotype.

Sixty-nine specimens of liver tissue from 53 infants with neonatal hepatitis or its sequelae were examined without knowledge of the alpha1-antitrypsin phenotype. Distinctive, diastase-resistant, PAS-positive, pure magenta-coloured, sharply defined globules, 2-20 microns in diameter were found in periportal and paraseptal hepatocytes in all liver biopsies from eight alpha1-antitrypsin deficient (PiZZ) infants biopsied after the age of 12 weeks. Such globules were not seen in biopsies from PiZZ individuals aged less than 12 weeks nor in individuals of normal alpha1-antitrypsin phenotype (PiMM). No other specific histological abnormality was found in PiZZ individuals, but in them giant-cell transformation was infrequent and liver damage was more severe, three of 14 cases developing cirrhosis in contrast to four of 27 PiMM subjects. The pathogenesis of liver disease in PiZZ individuals is discussed.     

ALPHA-1-ANTITRYPSIN DEFICIENCY IN ADULTS

A clinicopathological examination was carried out on eight adult patients with alpha-1-antitrypsin (ATT) deficiency. Phenotyping comfirmed five patients with PiMZ, two patients with PiZ-, and one patient with PiZZ. Cirrhosis was found in six of the patients, four of whom had a history of excessive ethanol comsumption. Hepatitis B surface antigen was positive in two patients with cirrhosis. Dysplastic change was present in four patients, although no neoplasia in the liver was found in all patients. All patients had periodic acid-Schiff positive and diastase resistant inclusions of hepatocytes, which were identified as ATT by indirect immunoperoxidase stain. The possibility of. the combined effects of ATT inclusions and such harmful stimuli such as alcohol or viral hepatitis infection may render the hepatocytes more susceptible to damage, and may contribute to development of cirrhosis.     

Alpha-1-antitrypsin deficiency in adults

A clinicopathological examination was carried out on eight adult patients with alpha-1-antitrypsin (ATT) deficiency. Phenotyping confirmed five patients with PiMZ, two patients with PiZ-, and one patient with PiZZ. Cirrhosis was found in six of the patients, four of whom had a history of excessive ethanol consumption. Hepatitis B surface antigen was positive in two patients with cirrhosis. Dysplastic change was present in four patients, although no neoplasia in the liver was found in all patients. All patients had periodic acid-Schiff positive and diastase resistant inclusions of hepatocytes, which were identified as ATT by indirect immunoperoxidase stain. The possibility of the combined effects of ATT inclusions and such harmful stimuli such as alcohol or viral hepatitis infection may render the hepatocytes more susceptible to damage, and may contribute to development of cirrhosis.     

Cirrhosis associated with partial deficiency of alpha-1-antitrypsin: A clinical and autopsy study

A 63 year old woman with cryptogenic cirrhosis, astiles, portal hypertension, and intermediate levels of alpha-l-antitrypsin of prolease inhibitor SZ phenotype who died of esophageal variceal hemorrhage is described. The partial deficiency of alpha-1-arrtihypsin and the diagnosis of cirrhosis were suspected one year prior to death because a needle biopsy liver showed PAS positive, diastase resistant cyloplasmic bodies within hepatocyles. This report illustrates three previously undescribed features: (1) Heterozygous protease inhibitor SZ phenotype may be associated with coarsely nodular cirrhosis in the older adult. (2) The large intracytoplasmic glycoprotein droplets that are distinctive by light microscopy are probably formalin induced aggregates of submicroscopic flocculent material. (3) 1n the older patients with aberrant alpha-1-anlilrypsin theflocculent material is present not only in the granular endoplasmic reticulmn but also in smooth endoplasmic reticulum vesicles and cytolysosomes.     

Alpha-1-antitrypsin and the liver: a routine immunohistological screen.

One hundred and eighty five consecutive liver biopsies were immunostained using anti-alpha-1-antitrypsin to assess the use of routine immunohistochemistry in the diagnosis of alpha-1-antitrypsin (AAT) deficiency. About half the livers showed staining of hepatocytes for alpha-1-antitrypsin, but most of these livers showed a panlobular pattern, possibly indicating increased synthesis of AAT. Only ten contained periportal granules, said to be typical of AAT deficiency. In cases in which serum was also available for quantitation and phenotyping there was no absolute relation between staining pattern, phenotype, and serum concentrations: the immunohistological screening technique, therefore, has limitations in the diagnosis of AAT deficiency in liver biopsy specimens.     

Niemann-Pick disease associated with liver disorders

We report a case of Niemann-Pick disease (NPD) with accumulation of sphingomyelin in reticuloendothelial system (RES), hepatocellular giant cell transformation (GCT), cirrhosis, and multiple hepatocellular adenomata in a 19-month-old girl. GCT, but no NP-cells, were seen at age 3 months by biopsy. Cirrhosis and hepatocellular adenomata were demonstrated in the liver at 19 months of age. Cytoplasmic, probably locally synthesized, globules of alpha-1-antitrypsin (A-1-AT) were accumulated in the hepatocellular adenomata. A-1-AT and alpha-fetoprotein (AFP) were present in the serum.     

Increased production of sonic hedgehog by ballooned hepatocytes

Ballooned hepatocytes distinguish non-alcoholic steatohepatitis (NASH) from steatosis. Such cells contain dilated endoplasmic reticulum and ubiquitin aggregates, characteristics of endoplasmic reticulum stress. Hepatocyte ballooning increases the risk for fibrosis in NASH, suggesting that ballooned hepatocytes release pro-fibrogenic factors. Hedgehog ligands function as pro-fibrogenic factors in liver diseases, but mechanisms for hedgehog ligand production remain poorly understood. We evaluated the hypothesis that endoplasmic reticulum stress induces hepatocyte production of hedgehog ligands that provide paracrine pro-fibrogenic signals to neighbouring cells. In livers from NASH patients, keratin 8/18 and ubiquitin staining demonstrated enlarged, keratin 8/18-negative/ubiquitin-positive hepatocytes (ballooned hepatocytes) that were positive for Sonic hedgehog. In order to model endoplasmic reticulum stress in vitro, primary mouse hepatocytes were treated with tunicamycin. Compared to vehicle, tunicamycin significantly increased Sonic hedgehog and Indian hedgehog expression. Furthermore, conditioned medium from tunicamycin-treated hepatocytes increased Gli-luciferase reporter activity 14-fold more than conditioned medium from vehicle-treated hepatocytes. Cyclopamine (hedgehog signalling inhibitor) abrogated the effect of conditioned medium from tunicamycin-treated hepatocytes, verifying that soluble hepatocyte-derived factors activate hedgehog signalling. Ballooned hepatocytes in NASH patients did not express the hedgehog target gene, Gli2, α-smooth muscle actin or vimentin, but were surrounded by Gli2-positive stromal cells expressing these myofibroblast markers. Trichrome staining demonstrated the accumulation of ballooned hepatocytes in areas of matrix deposition, and numbers of Sonic hedgehog-positive hepatocytes correlated with the degree of ballooning and fibrosis stage. Hepatocytes undergoing endoplasmic reticiulum stress generate hedgehog ligands which act as paracrine pro-fibrogenic factors for hedgehog-responsive stromal cells. These results help to explain why fibrosis stage correlates with hepatocyte ballooning in NASH.     

MORPHOLOGICAL AND BIOCHEMICAL ALTERATION IN THE RAT LIVER INDUCED BY MAPROTILINE

The fatty change in the liver induced in male rats by a new antide-pressant, maprotiline, given at high-dose was studied morphologically and biochemically.
The accumulation of trilglyceride in the liver was related to accelerated synthesis of fatty acid in the liver in males, which liver triglyceride was decreased in spite of increased synthesis of fatty acid from acetate in females. Secretion of lipoprotein granules was noted in both sexes. The sexual differences of triglyceride contents in the liver and serum was influenced by sexual hormone. Proliferation of smooth endoplasmic reticulum and "fingerprints" were found in treated rats and these were correlated with the induction of hepatic microsomal drug metabolizing enzymes. The "myeloid bodies" induced in hepatocytes were considered to be of lysosomal nature. Both morphological and biochemical alterations in the hepatocytes induced by maprotiline were reversible upon cessation of treatment.     

Quantitative microscopic evaluation of the endoplasmic reticulum in developing human liver.

Quantitative electron microscopic aspects of the liver have not been explored in detail, and the numerical characterization of tissue changes may contribute to the understanding of basic cellular mechanisms in disease processes. Sixteen liver biopsies from children 2 months to 18 years old were analyzed by stereology to study the composition and relative distribution of endoplasmic reticulum membranes within hepatocytes. The histologic aspects of the liver as well as the clinical laboratory data of these patients revealed no abnormalities when being observed for suspected hepatic ailment. Morphometric analysis of four tissue blocks per biopsy was undertaken by means of combined light and electron microscopy, using standard stereologic formulae. The results showed less endoplasmic reticulum in liver cells from children 2 to 9 months old. These low levels were accounted for by reduced surface of smooth membranes. There was a first-order relationship in the growth of smooth endoplasmic reticulum between 2 months and 4 years at a rate of 17.1 sq cm/hr, similar to the membrane accumulation rate in experimental animals. Membrane dimensions from Golgi apparatus and rough endoplasmic reticulum were cell-size dependent, and these organelles matured within 2 months of postnatal life. The significance of these findings resides in the low amounts of smooth endoplasmic reticulum membranes at an early age. This lack of membrane surface agrees with findings in developing liver of various species. Experimental studies showed reduced membrane population and low microsome-bound enzyme activities which, under normal circumstances, allow the hepatocyte to undertake detoxification and drug metabolizing processes. Thus, the reduced membrane availability of the liver in infants may account for their inability to metabolize foreign compounds.     

Alpha-1-Antitrypsin-Mangel

Summary Homozygous deficiency of alpha-1 antitrypsin is the most common inborn error or metabolism in Europe. Severe deficiency of this major protease inhibitor in serum is associated with chronic obstructive lung disease, chronic liver disease in adults and neonatal hepatitis. An overview is given of the role of heredity, and the diagnostic criteria and clinical and histological findings in this disorder. Emphysema seems to be caused by the free elastolytic activity of white cells, leading to the degradation of elastin. The pathophysiology of liver disease — less well understood — is discussed with special emphasis on the importance of heterozygous alpha-1 antitrypsin deficiency. Exogenous noxae seem to play an important role in the pathogenesis of heterozygous deficiency. In view of the 7% frequency of heterozygous alpha-1 antitrypsin deficiency in the European population and the role of noxae in the development of pulmonary and liver diseases, improved prophylaxis is mandatory.

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Abkürzungen -1-AT Alpha-1-Antitrypsin - PMN polymorphkernige Leukozyten - Pi Protease-Inhibitor Herrn Professor Dr. H. Losse zum 65. Geburtstag gewidmet     

Intracisternal hyalin and giant mitochondria in hepatocytes and oral contraceptives (author's transl)]

A 35-year-old woman who had used Non-Ovlon for 3 1/2 years was treated for anicteric hepatitis and underwent vaginal extirpation of the uterus due to carcinoma. Point biopsies were taken of the liver at this time and 1 year later, and histological and electron microscopic studies were also performed. The examination of the hepatocytes revealed intracisternal, hyaloplasmic, and mitochondrial hyalin, i.e. protein deposits in the endoplasmic reticulum, the cytoplasmic ground substance, and the mitochondria ("Giant mitochondria"), respectively. Coagulation necrosis of the hepatocytes was also observed. These abnormal protein deposits could not be related to abnormal alpha-1-antitrypsin synthesis in the liver. No regression in the protein deposits was observed 5 months after Non-Ovlon use was discontinued. It was also ascertained that the histological discovery of globular hyaline bodies can indicate that any or all of the various hyalins or cell mecrosis can exist simultaneously.     

Effect of protein deprivation and a reduced diet on the regenerating rat liver.

In rats fed a protein-free, calorie rich diet DNA synthesis is reduced, the mitotic index diminished and the proliferative response imparied. Nevertheless protein deficient hepatocytes retain a remarkable ability to hypertrophy and proliferate after partial hepatectomy. In pair-fed rats on a reduced semi-stravation diet deficient in calories these same parameters are not only diminished but their onset is also delayed. Electron microscopy revealed that the glycogen in the liver cells of these rats was severely depleted. This depletion was considered to be a critical factor in the delayed response to partial hepatectomy. Both groups showed a marked reduction of organelles, especially ribosomes and rough endoplasmic reticulum (RER). Golgi complexes persisted and were conspicuous. Rough endoplasmic reticulum was promptly reformed following partial hepatectomy.     

Morphological characteristics of ground glass hepatocytes in chronic hepatitis and liver cirrhosis]

Histochemical and electron microscopic examinations of liver punctates from 57 patients with chronic hepatitis and cirrhosis of the liver were carried out. "Ground Glass" hepatocytes were found to occur with similar frequency both in patients with HB-antigen in the blood serum and in patients with alcoholic involvement of the liver and no antigen in the blood serum. The presence of HB-antigen in the cytoplasm of such hepatocytes can be detected by staining of the sections with orsein, aldehydethionine and aldehydefucsin. The latter stain is more specific. Electron microscopically, the "Ground Glass" hepatocytes are characterized by marked hyperplasia of agranular endoplasmic reticulum in the lumen of which peculiar filaments are found in the presence of HB-antigen.     

Ultrastructural changes of hepatocyte organelles induced by chemicals and their relation to fat accumulation in the liver

Fatty liver was induced in the rats shortly after administration of cycloheximide, ethionine, orotic acid, monensin or colchicine. It was strongly suggested that derangements in one or more of the hepatic lipoprotein metabolic steps, which occur at the levels of endoplasmic reticulum, Golgi apparatus and secretory vacuoles lead to an accumulation of triglyceride within hepatocytes.