Fumiya Uchino

Ultrastructural evidence for intracellular formation of amyloid fibrils in macrophages

Early amyloid deposition in the spleen was studied by immunoelectron microscopy following the administration of rapid amyloid-inducing agents to mice. Two days after the injection of an amyloidenhancing factor and casein solution, a small amount of amyloid material was observed at the border of the white pulp and the marginal zone (perifollicular area) and also within the white pulp. At this stage, amyloid fibrils were seen mainly in an extracellular distribution along the cytoplasmic processes of reticular cells and also in the cytoplasmic invaginations of macrophages. By immunoelectron microscopy, gold particles labelled fibrillar structures in lysosome-derived organelles in some macrophages as well as dense bodies consisted of a homogeneous, granular matrix not having any recognizable fibrillar structures. Similar immunolabelled organelles were also observed in the amyloid resorption stage, although, at that stage, they commonly contained other phagocytized materials as well. From these findings, we suggest that at least some amyloid fibrils are polymerized in the cytoplasm of the macrophages by the proteolytic cleavage of previously pinocytized serum amyloid A protein (SAA).

Immunohistochemical classification of 140 autopsy cases with systemic amyloidosis

One hundred and forty autopsy cases of systemic amyloid‐osis were examined using the potassium permanganate method for distinction of amyloid A protein from other amyloid proteins and an immunohistochemical technique. Of those cases, amyloid proteins were identified in 121 cases. There were 68 cases of amyloid A‐related (AA) amyloidosis and these were the most common type among the cases (56.2%). There were 39 cases of immunoglobulin light chain‐related (AL) amyloidosis (32.2%), six cases of β2‐microglobulin‐related (Aβ2M) amyloidosis (5%), and five cases of transthyretin‐related (ATTR) amyloidosis (4.1%). Minute areas of amyloid deposits in four cases with AA were resistant to potassium permanganate pretreatment. In Aβ2M amyloidosis amyloid deposits were either resistant or sensitive to potassium permanganate pretreatment, from case to case. The coexistence of two different amyloid proteins was seen in three cases: one case had ATTR and Ax types, and two cases had Aβ2M and AA types. Some discrepancies were seen between the immunohistochemical typing and clinical classification of amyloidosis referred to in the Annual of the Pathological Autopsy Cases in Japan, for example, one case of AA type in myeloma‐associated amyloidosis and one case of AL type in secondary amyloidosis. From the present results, the importance of the immunohistochemical method in classifying amyloidosis is stressed.

Incidence and distribution of isolated atrial amyloid: Histologic and immunohistochemical studies of 100 aging hearts

The incidence and anatomic distribution of isolated atrial amyloid (IAA) in 100 aging hearts were studied histologically and immunohistochemically using antibodies against α‐human‐atrial natriuretic peptide (α‐ANP), human transthyre‐tin (TTR) and human amyloid P component (AP). Ninety‐one of 100 hearts (91%) had amyloid deposits in the atria. Amyloid deposits in all 91 hearts reacted with α‐ANP and AP antisera, and in four hearts other amyloid deposits that reacted with lTR antiserum were coincidentally seen in the atria. The prevalence of IAA deposition, using a semiquantitative evaluation, was significantly higher in the hearts from patients over 80 years of age, from women, those weighing over 450g, with a thickened left ventricular wall (>1.4 cm) and with multiple myocardial scars. IAA deposition showed a significant distribution in the auricle and left atrium; it was located mostly in the interstitium of the subendocardial layer and the subendorcardial myocardium. These results indicate that IAA occurs more frequently than previously appreciated in the elderly and in patients with certain cardiac disorders.

PATHOLOGICAL STUDY ON AMYLOIDOSIS

Five biopsy materials of human amyloidosis and experimental amyloidosis in mice induced by‐, casein injection were studied by an electron microscope, and the following results were obtained. 1. Amyloid consisted of amyloid fibrils with an approximate width of 100 Å. These fibrils were found in both biopsy materials of human cases and experimental amyloidosis in mice. Amyloid was produced by the reticulo‐endothelial cells which were functionally‐disturbed. 3. The process of amyloid production in the reticuro‐endothelial cells was essentially similar to that of collagen synthesis in the fibroblast. The protein synthesized in the granular reticulum was transported to the Golgi complex, and polymerization occurred in the lysosome, and finally complete amyloid fibrils were released from the cell.

Formation of Amyloid-Like Substance from Beta-2-Microglobulin in vitro

Although the pathogenesis has yet to be fully understood, beta 2-microglobulin (beta 2m) related amyloidosis is a frequent complication in long-term hemodialysis (HD) patients. In an attempt to clarify the association of two potential candidates with amyloidogenesis from beta 2m in HD patients, human urine-derived beta 2m solution alone or combined with glycosaminoglycans: hyaluronic acid, heparan sulfate, or serum amyloid P component (SAP) were dialyzed against physiological buffered solution (pH 7.4) using a microdialyzer in vitro for 72 h at 4 degrees C. This study demonstrates for the first time that SAP can play a crucial role in the formation of amyloid-like fibrils from beta 2m. This occurs by a direct influence on either the processing of a precursor protein, or protein folding, in vitro, by a short-period dialysis against a physiological buffered solution.

Hepatic amyloidosis in Japan: Histological and morphometric analysis based on amyloid proteins

To investigate the relationship between the tissue distribution and the types of amyloid proteins, the detailed histopathologic features of the available liver in 284 cases of amyloidosis were examined. We classified hepatic amyloidosis into three types, namely, the vascular pattern, parenchymal pattern, and stromal pattern according to the topographic distribution pattern of amyloid. Of the 152 amyloid A (AA) cases, all but one exhibited the vascular pattern; the single exception had the parenchymal pattern. Among 117 amyloid light chain (AL) cases, 51.3% exhibited the vascular pattern and 43.6% the parenchymal pattern. The stromal pattern was observed in 5.1% of the cases but was found only in AL amyloidosis. The parenchymal and stromal patterns in the liver seemed to be characteristic morphological distributions of AL amyloidosis. Routine histochemical study is useful to distinguish AL from AA, although some ethnic differences were apparent. Morphometric results showed that the walls of the hepatic arteries with amyloid deposition were significantly thicker than walls in arteries from the control group. The arterial walls in AA amyloidosis, especially, were significantly thicker than walls in AL amyloidosis of any pattern.

Amyloid protein of vessels in leptomeninges, cortices, choroid plexuses, and pituitary glands from patients with systemic amyloidosis

The cerebrum, cerebellum, and choroid plexuses from 16 patients with systemic amyloidosis, and the pituitary glands from 14 of these patients, were investigated histologically and immunohistochemically. Cerebrovascular amyloid (CVA) was found in the leptomeninges and cortices of six patients with systemic amyloidosis, including two patients with amyloid A protein (AA) amyloidosis related to serum amyloid A protein, one with AL amyloidosis related to immunoglobulin light chain (AL), two with familial type I amyloidotic polyneuropathy (FAP), and one with senile systemic amyloidosis (SSA). CVA protein from two patients with FAP reacted with anti-human prealbumin antibody similar to that of the visceral organs of these two patients. CVA in SSA reacted with anti-human prealbumin antibody and anti-beta protein antibody. Vascular amyloid was frequently noted in the pituitary glands and choroid plexuses of patients with systemic amyloidosis, and was found to be identical to that in the visceral organs (heart, kidney, and intestine) of these patients. CVA in the leptomeninges and cortices from two patients with AA amyloidosis and one with AL amyloidosis reacted with anti-beta protein monoclonal antibody but not with anti-human AA monoclonal antibody, anti-human A lambda antisera, and anti-human A kappa antisera. We suggest that amyloid proteins of AA and AL amyloidosis do not readily accumulate in the vessels in the leptomeninges and cortices even though the proteins circulate, and that beta protein is not derived from a serum precursor.

Carcinosarcoma of the gallbladder. A case report with immunohistochemical and ultrastructural studies

The authors present the histologic features, immunohistochemical findings, and ultrastructure of a carcinosarcoma of the gallbladder containing rhabdomyosarcoma as a mesenchymal element. A pedunculated polypoid tumor protruded into the lumen from the fundus of the gallbladder. The neoplasm contained two divergent components. One was malignant mesenchymal tissue with rhabdomyoblastic differentiation; the other was ordinary adenocarcinoma which was observed predominantly at the base of the polyp. Immunohistochemically, the cytoplasm of the rhabdomyoblasts stained with anti‐myoglobin, myosin, and muscle actin antibodies. Ultrastructurally, there were a large number of malignant mesenchymal tissues in which various stages of differentiated rhabdomyoblasts were noted. Ultrastructural study was particularly valuable for the identification of sarcomatous elements.

Malignant Cystosarcoma Phyllodes Of Prostate

A case of malignant cystosarcoma phyllodes of the prostate is reported in a 45‐year‐old male. This tumor was composed of benign columnar or squamous cystic folds and sarcomatous stroma including rhabdomyomatous elements. The prostatic origin of the tumor was clearly proved by the unlabeled immunoperoxidase method. ACTA PATHOL. JPN. 34: 663–668, 1984.

Amyloid Fibril Formation in the Rough Endoplasmic Reticulum of Plasma Cells from a Patient with Localized Aλ Amyloidosis

Evidence for amyloid fibril formation in rough endoplasmic reticulum (RER) of plasma cells from the duodenum of a 62-year-old man with localized A lambda amyloidosis is described. The inclusions in RER of plasma cells were composed of tightly packed, regular arrays of fibrils cut in both longitudinal and cross-sections. The fibrils within the inclusions, measuring 10 nm in width, were oriented parallel to the long axis of the inclusions. By immunoelectron microscopy with an antihuman A lambda antiserum, gold particles labeled the fibrils located both in the RER of plasma cells and in the extracellular space. In addition, electron-dense material in the dilated RER was occasionally labeled. These findings suggest that at least some amyloid fibrils are unequivocally created in the RER of plasma cells.