Yoshinobu Hoshii

Regression of abdominal aortic aneurysm by inhibition of c-Jun N-terminal kinase.

Abdominal aortic aneurysm (AAA) is a common disease among elderly people that, when surgical treatment is inapplicable, results in progressive expansion and rupture of the aorta with high mortality. Although nonsurgical treatment for AAA is much awaited, few options are available because its molecular pathogenesis remains elusive. Here, we identify JNK as a proximal signaling molecule in the pathogenesis of AAA. Human AAA tissue showed a high level of phosphorylated JNK. We show that JNK programs a gene expression pattern in different cell types that cooperatively enhances the degradation of the extracellular matrix while suppressing biosynthetic enzymes of the extracellular matrix. Selective inhibition of JNK in vivo not only prevented the development of AAA but also caused regression of established AAA in two mouse models. Thus, JNK promotes abnormal extracellular matrix metabolism in the tissue of AAA and may represent a therapeutic target.

Useful polyclonal antibodies against synthetic peptides corresponding to immunoglobulin light chain constant region for immunohistochemical detection of immunoglobulin light chain amyloidosis

For the immunohistochemical detection of immunoglobulin (Ig) light chain amyloidosis on formalin‐fixed, paraffin‐embedded tissue sections, we prepared polyclonal antibodies against synthetic peptides corresponding to positions 118–134 of Ig λ light chain and positions 116–133 of Ig κ light chain. Nineteen cases of systemic Ig λ light chain amyloidosis (Aλ amyloidosis), 10 cases of systemic Ig κ light chain amyloidosis (Aκ amyloidosis), one case of immunohistochemically unclassified systemic amyloidosis and five cases of localized Aλ amyloidosis were tested with these antibodies. Anti‐λ (118–134) antiserum and the affinity‐purified antibody both reacted with 18 of the 19 cases of systemic Aλ amyloidosis and all cases of localized Aλ amyloidosis, although the immunoexpression was somewhat variable in intensity in different areas within the same specimen in both systemic and localized amyloidosis. The signal intensities in plasma cells and serum reacted for anti‐λ (118–134) antiserum were weaker than signals obtained with commercially available anti‐Ig λ light chain antibodies. Anti‐κ (116–133) antiserum and the affinity‐purified antibody reacted with nine of the 10 cases of systemic Aκ amyloidosis. We conclude that these antibodies against synthetic peptides corresponding to the Ig light chain constant region are useful for the classification of amyloidosis on formalin‐fixed, paraffin‐embedded tissue sections.

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.

Transthyretin-derived amyloid deposition on the gastric mucosa in domino recipients of familial amyloid polyneuropathy liver

Familial amyloid polyneuropathy (FAP) is a form of hereditary generalized amyloidosis. Liver tissue explanted from FAP patients has normal structure and function, except for the production of amyloidogenic variant transthyretin (TTR), and domino liver transplantation (DLT) using grafts from FAP patients was first performed in 1995. FAP symptoms usually develop in genetically determined individuals after the age of 20, but it is difficult to estimate when FAP symptoms will appear in domino recipients. Concerning this problem, histological findings showing amyloid deposition have recently been obtained in a few domino recipients of FAP livers. This study investigated the presence of de novo amyloid deposition in the gastroduodenal mucosa of domino recipients transplanted at our institution. Biopsy of gastroduodenal mucosa was carried out in 5 recipients of FAP livers and TTR‐derived amyloid deposits were detected in 2 patients, both of whom had undergone DLT 47 months previously. In FAP liver recipients, de novo systemic amyloid deposition may begin much sooner than previously supposed. Therefore, careful follow‐up of domino recipients of FAP livers is required. Liver Transpl, 2006.

Acceleration of murine AA amyloidosis by oral administration of amyloid fibrils extracted from different species.

We herein report that experimental murine amyloid A (AA) deposition is accelerated by oral administration of semipurified amyloid fibrils extracted from different species. Three groups of mice were treated with semipurified murine AA amyloid fibrils, semipurified bovine AA amyloid fibrils or semipurified human light chain‐derived (Aλ) amyloid fibrils for 10 days. After 3 weeks, each mouse was subjected to inflammatory stimulation by subcutaneous injection with a mixture of complete Freund’s adjuvant supplemented with Mycobacterium butyricum. The mice were killed on the third day after the inflammatory stimulation, and the spleen, liver, kidney and gastrointestinal tract were examined for amyloid deposits. Amyloid deposits were detected in 14 out of 15 mice treated with murine AA amyloid fibrils, 12 out of 15 mice treated with bovine AA amyloid fibrils and 11 out of 15 mice treated with human Aλ amyloid fibrils. No amyloid deposits were detected in control mice receiving the inflammatory stimulant alone or in amyloid fibril‐treated mice without inflammatory stimulation. Our results suggest that AA amyloid deposition is accelerated by oral administration of semipurified amyloid fibrils when there is a concurrent inflammatory stimulation.

Confocal observation of senile plaques in Alzheimer's disease: senile plaque morphology and relationship between senile plaques and astrocytes.

Senile plaques In the brains of Alzheimers disease (AD) were examined by confocal laser scanning microscopy (CLSM) with the following three findings. First, in sections stained with Congo red, the serial CLSM images of optical sections clearly revealed that a classic plaque is composed of a plaque core and a corona. Radially arranged process‐like structures, corresponding to bundles of amyloid fibrils, formed amyloid cores and stronger signals were detected in the center of some cores. Second, in sections stained with Congo red and anti‐gllal fibrillary acidic protein (GFAP), reactive astrocytes were found around the senile plaques and many astrocytlc processes surrounded the plaque cores and some processes had penetrated into them. Third, three‐dimensional reconstruction on classic plaque revealed that the surface of classic plaque showed a ‘coral‐like’ appearance.

VAD with or without subsequent high-dose melphalan followed by autologous stem cell support in AL amyloidosis: Japanese experience and criteria for patient selection.

Patients with AL amyloidosis were treated with VAD (vincristine, doxorubicin and dexamethasone) with or without high-dose melphalan followed by auto-PBSCT according to eligibility criteria based on disease severity, and prospectively investigated the therapeutic benefits and complications. Thirty-one patients were enrolled in this study. VAD and subsequent high-dose melphalan with auto-PBSCT were performed only in patients who met all of the eligibility criteria. Among patients ineligible for this treatment, VAD alone was performed in those with satisfactory general status. Eleven patients met the eligibility criteria, and of these, 7 were treated with VAD and subsequent high-dose melphalan with auto-PBSCT. Seven patients received VAD alone, and the remaining 17 were treated with the supportive therapy. Among the 14 patients treated with chemotherapy, 9 (5 of the 7 treated with VAD and high-dose melphalan, and 4 of the 7 treated with VAD alone) showed complete hematological response with apparent improvement of amyloidosis-related clinical symptoms. Serious complications of chemotherapy were cytomegalovirus infection and pneumocystis carinii pneumonia seen in 1 and 2 patients, respectively. These chemotherapies may be effective for reduction of M-protein and are also useful in improving of amyloidosis-induced organ dysfunction. In patients who cannot tolerate high-dose melphalan, VAD alone is a potent therapeutic option, although there are possible harmful effects on the heart and peripheral nerve.

Induction of Murine AA Amyloidosis by Various Homogeneous Amyloid Fibrils and Amyloid-like Synthetic Peptides

We investigated amyloid‐enhancing factor (AEF) activity of amyloid fibrils extracted from amyloid‐laden livers of mice, cow, cheetah, cat and swan. All amyloid fibrils were confirmed to be amyloid protein A (AA) by an immunohistochemical analysis. We found that these fibrils accelerated the deposition of amyloid in an experimental mouse model of AA amyloidosis. Furthermore, the degree of deposition was dependent on the concentration of fibrils. When we compared the minimal concentration of amyloid fibrils needed to induce deposition, we found that these fibrils showed different efficiencies. Murine amyloid fibril induced amyloid deposition more efficiently than cow, cat, cheetah or swan amyloid fibrils. These data suggest that amyloid deposition is preferentially induced by amyloid fibrils with the same primary sequence as the endogenous amyloid protein. We then analysed the AEF activity of synthetic peptides, synthesized corresponding to amino acids 1–15 of mouse SAA (mSAA), 2–15 of cow SAA (bSAA), 1–15 of cat SAA (cSAA), which was the same as cheetah, and the common amino acids 33–45 of these four SAA (aSAA). We found that mSAA, bSAA and cSAA formed amyloid‐like fibrils in morphology and showed similar AEF properties to those of native amyloid fibrils. Although aSAA also formed highly ordered amyloid‐like fibrils, it showed weaker AEF activity than the other synthetic fibrils. Our results indicate that amyloidosis is transmissible between species under certain conditions; however, the efficiency of amyloid deposition is species‐specific and appears to be related to the primary amino acid sequence, especially the N‐terminal segment of the amyloid protein.

Duodenal follicular lymphoma lacks AID but expresses BACH2 and has memory B-cell characteristics

We have reported previously that duodenal follicular lymphoma (FL) is distinct from nodal FL and showed more resemblance to mucosa-associated lymphoid tissue lymphoma, and that FL frequently involved the duodenal second portion. In the present study, we examined duodenal FLs and gastric/colonic FLs to clarify the clinicopathological and immunological differences between the tumor types. We analyzed 8 samples of gastric FL, 17 of duodenal ones, and 5 of colonic/rectal ones, and characterized them by immunohistochemistry, immunogenotyping, and histology. Gastric and colonic FLs presented in submucosal to subserosal areas, whereas duodenal ones presented in the mucosal to submucosal layers. Immunohistochemical analysis revealed that duodenal FLs exhibited the following phenotypes: CD10 (+), B-cell lymphoma 2 (BCL-2) (+), BCL-6 (+), activation-induced cytidine deaminase (AID) (−), BACH2 (+), CD27 (+), MUM-1 (−), Blimp-1 (−), and loose CD21 network (duodenal pattern). Gastric/colonic FLs exhibited the following phenotypes: CD10 (+), BCL-2 (+), BCL-6 (+), AID (+), BACH2 (+), CD27 (−), MUM-1 (−), Blimp-1 (−), and a dense CD21 network (nodal pattern). Expression of AID and CD27 in lymphoma cells and the CD21 network pattern were considerably different between duodenal FLs and gastric/colonic ones. Moreover, in situ hybridization revealed that, in the duodenal FLs, BACH2 was expressed at the periphery of the tumor follicle and tumor villi. The number of immunoglobulin heavy-chain variable domains VH4 and VH5 were higher in duodenal follicular lymphomoas than in gastric FLs. The lymphoma cells of duodenal FLs are different from those of gastric/colonic FLs, and duodenal FL is distinct even within the gastrointestinal tract. Somatic hypermutation in immunoglobulin genes and CD27 expression are hallmarks of memory B cells. We suggest that duodenal FL cells are in the memory B-cell stage, and require BACH2 instead of AID for ongoing mutation.

Unexpectedly high incidence of visceral AA-amyloidosis in slaughtered cattle in Japan.

Experimental mouse AA amyloidosis can be transmissible by dietary ingestion of amyloid fibrils and it is well known that AA amyloidosis occasionally develops in aged cattle. Bovine liver and intestine have conventionally been used in Oriental foods, and the incidence of visceral AA amyloidosis in slaughtered cattle was evaluated. Renal tissues from 302 aged cattle older than 4 years were obtained from a local abattoir. Amyloid deposition was microscopically examined and amyloid protein was immunochemically determined. Renal amyloid deposition was seen in 15 out of 302 cattle with no previous history of diseas, an incidence of 5.0%. Amyloid protein in these cattle was AA and they had pathological findings in their visceral organs on gross examination. The incidence of visceral AA amyloidosis in slaughtered cattle in this study was disturbingly high compared with those (0.4–2.7%) previously reported from Japan and other foreign countries. AA amyloidosis is a life-threatening complication in patients with chronic inflammatory diseases and these patients at risk should avoid ingesting food that may possibly contain AA amyloid fibrils. More detailed information on cattle amyloidosis is required to guarantee the safety of our food.