Pattern Of Amyloid Deposition Research Articles

Progression of Cerebral Amyloid Angiopathy in Transgenic Mouse Models of Alzheimer Disease

Cerebral amyloid angiopathy (CAA), the deposition of beta-amyloid (Abeta3) in cerebral vessels, has been implicated as a common cause of hemorrhagic stroke and other forms of vascular disease. CAA is also a frequent concomitant of Alzheimer disease (AD). While the longterm consequences of CAA are well recognized from clinical and pathologic studies, numerous questions remain unanswered regarding the progression of the disease. Examination of CAA in traditional histologic sections does not easily allow for characterization of CAA, particularly in leptomeningeal vessels. In order to approach this topic, we used low magnification imaging of intact, postmortem brains from transgenic mouse models of AD-like pathology to define the spatial and temporal characteristics of CAA in leptomeningeal vessels. Imaging of brains from 10- to 26-month-old animals demonstrated a stereotypical pattern to the development of CAA, with vessels over the dorsal surface of the brain showing an anterior-to-posterior and large-to-small vessel gradient of involvement. High magnification imaging revealed that CAA deposition began with a banding pattern determined by the organization of the vascular smooth muscle cells. Further analysis of the pattern of amyloid deposits showed shrinkage and disappearance of the gaps between clusters of amyloid bands, gradually reaching a confluent pattern. These data led to a classification system to describe the severity of CAA deposition and demonstrate the potential of using intact brains to generate maps defining the progression and kinetics of CAA. This approach should lead to more informed analysis of the consequences of evolving therapeutic options for AD on this related form of vascular pathology.

Amyloid deposits in transthyretin‐derived amyloidosis: cleaved transthyretin is associated with distinct amyloid morphology

The pathological fibrillar deposits found in the heart and other organs of patients with senile systemic amyloidosis (SSA) and Swedish familial amyloidotic polyneuropathy (FAP) contain wild-type (wt) and a mutant form of transthyretin (TTR), respectively. Previously, it was reported that these two forms of amyloid have different molecular features and it was thus postulated that the mechanism responsible for TTR fibrillogenesis in SSA and FAP may differ. To document further the nature of the amyloid in these entities, detailed morphological, histochemical, immunological, and structural analyses of specimens obtained from 14 individuals with SSA and 11 Swedish FAP patients have been performed. Two distinct patterns of amyloid deposition (designated A and B) were evident. In pattern A, found in all SSA and five of 11 FAP cases, the amyloid had a homogeneous but patchy distribution within the sub-endocardium, sub-epicardium, and myocardium; exhibited weak congophilia and green birefringence; and was composed of tightly packed, short, unorientated fibrils. This material contained mainly approximately 79-residue C-terminal fragments of the amyloidogenic precursor protein. In pattern B, seen in the six other FAP patients, the amyloid appeared as thin streaks throughout the cardiac tissue; often surrounded individual muscle cells; was strongly congophilic and birefringent; had long fibrils arranged in parallel bundles, often penetrating into myocytes; and was composed of virtually intact TTR molecules. These findings provide substantive evidence for the morphological and structural heterogeneity of TTR fibrils and suggest that the two types of deposition may reflect fundamental differences in the pathogenesis of the TTR-associated amyloidoses.

Disruption of Corticocortical Connections Ameliorates Amyloid Burden in Terminal Fields in a Transgenic Model of Aβ Amyloidosis

We demonstrated previously that amyloid precursor protein (APP) is anterogradely transported from the entorhinal cortex (ERC) to the dentate gyrus via axons of the perforant pathway. In the terminal fields of these inputs, APP undergoes proteolysis to generate C-terminal fragments containing the entire amyloid beta peptide (Abeta) domain. The present study was designed to test the hypothesis that APP derived from ERC neurons is the source of the Abeta peptide deposited in the hippocampal dentate gyrus in Alzheimer's disease (AD) and in transgenic mice with Abeta amyloidosis. We used mice harboring two familial AD-linked genes (human APP Swedish and presenilin1-DeltaE9), in which levels of Abeta (especially Abeta(42)) are elevated, leading to the formation of amyloid plaques, and lesioned the ERC to interrupt the transport of APP from ERC to hippocampus. Our results show that, on the side of ERC lesion, numbers of APP-immunoreactive dystrophic neurites and Abeta burden were significantly reduced by approximately 40 and 45%, respectively, in the dentate gyrus compared with the contralateral side. Reductions in APP and Abeta were more substantial in the molecular layer of the dentate, i.e., a region that contains the ERC terminals, and were associated with a parallel decrease in total APP and Abeta measured by Western blot and ProteinChip immunoassays. Silver and thioflavine staining confirmed the reduction of amyloid plaques on the side of deafferentation. These results are consistent with the hypothesis that ERC may be the primary source of amyloidogenic Abeta in the dentate gyrus, and they suggest an important role of corticocortical and corticolimbic forward connections in determining patterns of amyloid deposition in AD.

Cerebrovascular involvement in systemic AA and AL amyloidosis: a clear haematogenic pattern.

Amyloid deposits in cerebral vessels are common in beta-amyloid diseases (Alzheimer's disease, congophilic amyloid angiopathy, Down's syndrome and hereditary cerebral amyloidosis with haemorrhage of the Dutch type). We report of 20 autopsies on patients who had died with systemic amyloidosis of the AA, Alambda and Akappa types: the brains were examined for the occurrence of amyloid. Vascular amyloid was detected in choroid plexus (in 17 of 20 cases), infundibulum (5 of 8), area postrema (6 of 11), pineal body (3 of 7) and subfornical organ (2 of 3), but not in cortical and leptomeningeal vessels. Immunohistochemical classification of the cerebral amyloid and the systemic amyloid syndrome showed identity proving the same origin of both. The distribution is indicative of a haematogenic pattern of amyloid deposition in systemic amyloidosis and is different from that in Alzheimer's, prion, ATTR and cystatin C diseases. It corresponds to areas of the brain with a "leaky" blood-brain barrier. Additionally, all the cases with AA amyloidosis exhibited an Abeta coreactivity in choroid plexus vessels. In one exceptional case, Abeta reactivity of AA amyloid also occurred outside of the brain.

The progression of β-amyloid deposition in the frontal cortex of the aged canine

Brains from 41 aged canines (≥10 years of age) were examined immunohistochemically to characterize the laminar distribution and age-related progression of β-amyloid (A β) in frontal cortex. We classified the A β patterns into four distinct types. Type I was characterized by small, faint deposits of A β in deep cortical layers. Type II consisted of diffuse deposits of A β mainly in layers V and VI. Type III had both dense plaques in superficial layers, and diffuse deposits in deep layers. Finally, Type IV had solely dense plaques throughout all layers of cortex. We compared the A β distribution pattern between the Old canines (10–15 years, n=22) and the Very Old canines (>15 years, n=19). The Old group primarily had negative staining, or Type I and Type II patterns of amyloid deposition (73%). Conversely, the Very Old group had predominantly Types II, III and IV deposits (89.5%), a difference that was significant ( P<0.05). We suggest that A β deposition in canine frontal cortex is a progressive age-related process beginning with diffuse deposits in the deep cortical layers followed by the development of deposits in outer layers. In support of this hypothesis, the deeper layer diffuse plaques in the Very Old group of dogs also contain the largest proportion of β-amyloid with an isomerized aspartic acid residue at position 7, indicating that these deposits had been present for some time. We also observed fiber-like A β immunoreactivity within regions of diffuse A β deposits. These fibers appeared to be degenerating neurites, which were negative for hyperphosphorylated tau. Therefore, these fibers may represent a very early form of neuritic change that precede tau hyperphosphorylation or develop by an alternative pathway.

Amyloid Goiter:A Clinicopathologic Study of 14 Cases and Review of the Literature

The authors report the clinicopathologic features of 14 cases of amyloid goiter (AG). Eleven patients were males and three females with ages ranging from 23 to 75 years (median, 54 years). Eight patients had secondary amyloidosis and six had primary amyloidosis. Nine cases were identified at autopsy. In symptomatic patients (n = 5), the clinical presentation included a nontender, rapidly enlarging neck mass with associated dysphagia, dyspnea or hoarseness. Clinical or laboratory evaluation failed to detect evidence of thyroid dysfunction. The histologic appearance of the thyroid predominantly consisted of diffuse amyloid deposition surrounding thyroid follicles. In two cases, a nodular pattern of amyloid deposition was seen resulting in compression and distortion of the follicular architecture. Areas of mature adipose tissue and focal lymphocytic thyroiditis with or without foreign-body type-giant cells were seen in approximately one third of the cases. Confirmation of amyloid was made by the presence of congophilia and apple-green birefringence under polarized-light microscopy. Immunohistochemical evaluation demonstrated the presence of amyloid A immunoreactivity. No Immunoreactivity was seen with calcitonin or thyroglobulin. Fine-needle aspiration may facilitate the diagnosis, as occurred in one the patients. In symptomatic patients, thyroidectomy is warranted to alleviate pressure symptoms.

Amyloidosis and endomyocardial biopsy: Correlation of extent and pattern of deposition with amyloid immunophenotype in 100 cases

The heart is subject to involvement by primary (AL), senile (AS), and familial (AF) forms of amyloidosis, but the frequency, severity, and therapy of amyloid-related cardiac symptoms differ depending on the type of amyloidosis present. Endomycardial biopsy is a safe and reliable procedure for diagnosing cardiac amyloidosis, and immunohistochemical staining of routinely processed biopsy specimens can be performed to classify the type of amyloid present. However, whether or not the type can be determined from the histologic extent and pattern of amyloid deposition is unclear. Endomyocardial biopsy specimens from 100 patients with cardiac amyloidosis (74 AL, 22 AS, 4 AF) were examined, and the histologic extent and pattern of amyloid deposition were correlated with the amyloid immunophenotype. No difference in the extent of amyloid deposition was identified among the three types. Interstitial nodules of amyloid were more common in AS (82%) than in AL (50%, p = 0.0129), whereas vascular involvement was more frequently observed in AL (88%) than in AS (26%, p < 0.0001). Endocardial and interstitial pericellular deposition occurred with similar frequencies in both groups. Although statistically significant differences existed in the patterns of amyloid deposition, they did not allow reliable distinction between the different types in individual cases. Consequently, in older patients without serum or urinary light chains, immunohistochemical staining is recommended to distinguish AL from AS types of amyloid in cardiac biopsy tissues.

Gerstmann‐Sträussler‐Scheinker Disease and the Indiana Kindred

Gerstmann-Sträussler-Scheinker disease is an autosomal dominant disorder with a wide spectrum of clinical presentations including ataxia, spastic paraparesis, extrapyramidal signs, and dementia. The patients present with symptoms in the third to sixth decade of life and the mean duration of illness is five years. Mutations at codons 102, 105, 117, 145, 198 and 217 of the open reading frame of the prion protein gene have been associated with GSS disease. As a result of the mutations, a substitution at the corresponding residues of the prion protein occurs, or as in the case of the STOP mutation at codon 145, a truncated protein is produced. Neuropathologically, the common denominator is a cerebral prion protein amyloidosis; however, there is significant variability in the pattern of amyloid deposition in regions of the central nervous system among reported families. Amyloidosis coexists with severe spongiform degeneration in patients with the mutation at codon 102, and with neurofibrillary degeneration in the patients with mutation at codons 145, 198 and 217. The development of a transmissible spongiform encephalopathy in animals inoculated with brain tissue from affected subjects with mutation at codon 102 suggests that in some forms of genetically-determined Gerstmann-Sträussler-Scheinker disease, and particularly those characterized by severe spongiosis, amyloidogenesis and production of an infectious "agent" occur concomitantly via mechanisms that are only partially understood.

Systemic amyloidosis in transgenic mice carrying the human mutant transthyretin (Met 30) gene. Pathological and immunohistochemical similarity to human familial amyloidotic polyneuropathy, type I.

To analyze the pathologic processes of amyloid deposition in type I familial amyloidotic polyneuropathy (FAP), mice were made transgenic by introducing the human mutant transthyretin (TTR) gene(MT-hMet 30). An inbred strain of mouse, C57 BL/6, was chosen. Transgenic mice were killed using ether anesthesia at 3-mo intervals up to 24 mo after birth. In these transgenic mice, amyloid deposition started in the gastrointestinal tract, cardiovascular system, and kidneys and extended to various other organs and tissues with advancing age. The pattern of amyloid deposition was similar to that observed in human autopsy cases of FAP, except for its absence in the choroid plexus and in the peripheral and autonomic nervous systems. We extracted the amyloid fibrils from kidneys of these mice with a human mutant TTR gene and analyzed them immunochemically and electronmicroscopically. Deposited amyloid was shown to be composed of human mutant TTR and mouse serum amyloid P component. Amyloid fibril from transgenic mice was morphologically and immunohistochemically similar to that of human FAP. The most striking pathologic feature of the transgenic mice was the absence of amyloid deposition in the peripheral and autonomic nervous tissues. Thus, other intrinsic factors may be involved in amyloid deposition in the nervous tissues of human FAP.

AA-like amyloid deposits confined to arthritic joints in two dogs with rheumatoid arthritis

Two dogs with clinical, serological, radiographic and pathological changes similar to those of rheumatoid arthritis of man and a previously undescribed pattern of amyloid deposits are described. As revealed by light and electron microscopical investigations, amyloid fibrils were found exclusively in articular tissue structures of arthritic joints and in one tonsil of one dog. Based on our immunohistochemical results, the amyloid protein is believed to be of a local AA type.

Alzheimer cortical neurons containing abundant amyloid mRNA. Relationship to amyloid deposition and senile plaques

Since the detailed molecular events leading to the formation of amyloid-containing senile plaques of the Alzheimer's disease (AD) brain are incompletely understood, the present studies were undertaken to address this issue using a combination of molecular and cytochemical approaches. Amyloid precursor protein riboprobes containing the A4(β-amyloid) domain were applied to cortex using the in situ hybridization method to examine the distribution of neuronal amyloid mRNA in relation to the laminar pattern of amyloid deposition and the localization of plaques. The derived data indicated that high levels of amyloid mRNA can be synthesized by AD cortical neurons that appeared to be morphologically intact. The distribution of these cells was not coincident with the cortical laminar pattern that is typical of amyloid deposits observed after immunostaining with anti-A4 monoclonal antibodies. Further, there was no obvious relationship between neurons containing abundant amyloid mRNA and the distribution of plaques identified by thioflavin S staining. While the neuronal synthesis of amyloid may be a significant factor at some point during plaque formation, it may not be the exclusive determinant. The possibility is raised that processes affecting secretion, diffusion, and/or transport of amyloid away from neuronal or non-neuronal cells of origin to sites of deposition may be meaningful aspects of the molecular pathology of Alzheimer's disease.

Histomorphological variations in systemic AA amyloidosis: clues of AA protein polymorphism.

The histological location of amyloid within various organs in 25 cases of systemic AA amyloidosis was studied with a view to determine whether different morphological patterns exist in this category of amyloidosis. Although morphological variations due to progressive severity of disease were observed, there were appreciable variations in the patterns of amyloid deposition in the kidney and spleen that could not be simply explained on those grounds. Eleven (61%) of 18 kidneys examined showed severe glomerular involvement with mild degrees of vascular deposition while the remaining seven showed predominantly vascular involvement. The glomerular pattern appeared to be more ominous, being significantly associated with severe proteinuria or chronic renal failure. In nine (69%) of 13 spleens examined, amyloid was confined to the walls of small and medium-sized arteries while in the remaining four, vascular involvement was less severe and amyloid was deposited mainly along the reticulin of the white pulp. Possible explanations for these different patterns included resorption and redistribution of amyloid within the body during the course of the disease, and variation in tissue deposition as a manifestation of polymorphism of amyloid proteins. The latter appeared more feasible in view of the recent demonstration of SAA polymorphism and AA heterogeneity in man.

Morphologic differences in the pattern of liver infiltration between systemic AL and AA amyloidosis

Biopsy and necropsy tissue from 31 unselected patients with systemic amyloidosis, in which there was histologic evidence of liver involvement, were reviewed with reference to the location and pattern of amyloid deposition in the liver. Amyloidosis was classified into AA and AL types on the basis of immunohistochemistry and permanganate reaction of the amyloid deposits. Nineteen were categorized as AA (secondary) and 12 as AL (primary) amyloidosis. Deposition of AA amyloid was limited to the walls of vessels in the portal tract, constituting a "vascular" pattern. In AL amyloidosis, the deposits exhibited a "sinusoidal" pattern in that they were seen along hepatic sinusoids as well as in vessel walls. This difference was statistically significant (P less than .001). The histologic pattern of liver infiltration offers a valuable clue in the classification of systemic amyloidosis and provides information that may be useful in the selection of patients for therapy.

Corneal Amyloidosis Associated with Keratoconus

Nodular, gray-white, central corneal opacities which extended from the subepithelial zone through the anterior four fifths of the stroma developed in a 50-year-old man with a longstanding history of hard contact lens wear for keratoconus. Results of histopathologic analysis of the corneal button obtained at the time of penetrating keratoplasty disclosed that the opacities were composed of amyloid. Corneal amyloidosis is rarely found in association with keratoconus. Although there were some similarities in the pattern of amyloid deposition to that seen in primary familial amyloidosis of the cornea, the authors believe that their patient is more likely to have had a secondary amyloidosis. Corneal amyloidosis should be considered in keratoconus patients with development of unusual forms of central corneal opacification.

Amyloid deposits in lymph nodesA morphologic and immunohistochemical study

In a series of approximately 80,000 lymph nodes, amyloid deposition was found in 18; 12 of those nodes were selected, on the basis of availability of specimens, for investigation by immuno-histochemical typing to identify the protein of origin and by correlation with morphologic criteria and clinical information. Four patterns of amyloid deposition were identified: lymph node vessel involvement, follicular deposition, diffuse deposition, and a combination of follicular and diffuse deposition. All cases were classified immunohistochemically with the amyloid type-specific antisera anti-AA, anti-A λ, anti-A κ, anti-ASc1, and anti-AF. Immunoglobulin-derived protein (AL) in lymph nodes was found in every case of isolated amyloidosis, lymphoplasmacytic/lymphoplasmacytoid immunocytoma, plasmacytoma, and idiopathic amyloidosis. Among the cases of AL amyloidosis were nine of A λ and one of the A κ type. AA protein was present in two cases of reactive systemic amyloidosis. There was no useful morphologic correlation with the immunohistochemically identified amyloid types.

Amyloid deposits in lymph nodes: A morphologic and immunohistochemical study

In a series of approximately 80,000 lymph nodes, amyloid deposition was found in 18; 12 of those nodes were selected, on the basis of availability of specimens, for investigation by immunohistochemical typing to identify the protein of origin and by correlation with morphologic criteria and clinical information. Four patterns of amyloid deposition were identified: lymph node vessel involvement, follicular deposition, diffuse deposition, and a combination of follicular and diffuse deposition. All cases were classified immunohistochemically with the amyloid type-specific antisera anti-AA, anti-A lambda, anti-A kappa, anti-ASc1, and anti-AF. Immunoglobulin-derived protein (AL) in lymph nodes was found in every case of isolated amyloidosis, lymphoplasmacytic/lymphoplasmacytoid immunocytoma, plasmacytoma, and idiopathic amyloidosis. Among the cases of AL amyloidosis were nine of A lambda and one of the A kappa type. AA protein was present in two cases of reactive systemic amyloidosis. There was no useful morphologic correlation with the immunohistochemically identified amyloid types.

Clinicopathological importance of deposits of amyloid in the femoral head.

The pattern of amyloid deposits in the femoral head is described in four cases, two of which had deposits of amyloid related to age and two of which had generalised systemic amyloidosis (one of primary amyloidosis, one of multiple myeloma). The deposition of amyloid in the articular cartilage of the femoral head was similar in all four cases. Heavy deposits of synovial amyloid were identified in the case with primary amyloidosis and in one of the cases with amyloidosis related to age. Both cases of generalised systemic amyloidosis showed abundant deposits of amyloid in the bone marrow. Amyloid was not present in the bone marrow of either case with amyloidosis related to age. The importance of these findings is discussed in relation to the pathogenesis of the arthropathy syndrome of a rheumatoid type described in cases of primary amyloidosis and multiple myeloma.

Clinical Significance of Histopathologic Patterns of Cardiac Amyloidosis

Cardiac amyloidosis may be asymptomatic or an important cause of progressive heart failure and refractory arrhythmia. To identify the morphologic markers of clinically significant cardiac amyloidosis, we analyzed the hearts of 47 patients with autopsy-proven cardiac amyloidosis (21 with primary amyloidosis [AL] and 26 with senile cardiac amyloidosis [SCA]) histologically for the extent and pattern of amyloid deposits. The extent of amyloid deposition was graded 1 through 4, corresponding with less than 10%, 10 to 25%, 26 to 50%, and more than 50% histologic involvement of the myocardium, respectively. The pattern of deposits was classified as nodular, perifiber, or mixed type, and the presence or absence of vascular involvement was determined. The hearts with primary amyloidosis showed predominantly high-grade deposits (76% grades 3 and 4), a perifiber (65%) or mixed (30%) pattern of deposits, and frequent (90%) vascular involvement. The hearts with senile cardiac amyloidosis tended to have low-grade deposits (62% grades 1 and 2), a nodular pattern (92%) of deposits, and infrequent (4%) vascular involvement. Clinically significant cardiac amyloidosis was associated with grade 2 or greater amyloid deposits in the heart and with involvement of intramyocardial arterioles.

Familial renal amyloidosis in Abyssinian cats.

Medullary and glomerular amyloidosis, papillary necrosis, and secondary interstitial disease were diagnosed in eight related adult Abyssinian cats from two catteries. The lesions were similar to those in two unrelated mongrel cats with renal amyloidosis. Ultrastructurally, the patterns of amyloid deposition were as described in other species, although medullary deposition predominated. Potassium permanganate oxidation blocked Congo red staining of the deposits suggesting that they contained amyloid A protein (secondary amyloid). The disease may be a model of familial secondary amyloidosis and offers an opportunity to study the pathogenesis of both amyloid deposition and papillary necrosis. The histochemical characteristics of feline renal amyloid require careful attention to technique. Section thickness affects Congo red affinity and both dichroism as well as birefringence should be considered when interpreting staining reactions. Thioflavine-T may be the preferred stain for identification of small deposits of amyloid. Variation in section thickness markedly affected the degree of potassium permanganate oxidation.

Amyloidosis and the carpal tunnel syndrome

A histologic study was carried out on tissues from 87 patients who had undergone surgical decompression of the median nerve to determine the incidence and relationship of amyloid deposition to the carpal tunnel syndrome. Using histochemical and electron microscopic technics, amyloid was found in tissues from two male patients with the apparent idiopathic form of the disease. These data are significant, in that they show that screening of tissues from such patients is of value. This study is the first to demonstrate the submicroscopic pattern of amyloid deposits associated with the carpal tunnel syndrome. The focal deposits of the fibrils show pericollagenous distribution with separation of the individual collagen fibers, a morphologic pattern which contradicts recent reports based on light microscopy.