Widespread occurrence of AP in amyloidotic tissues. An immunohistochemical observation

Amyloid P component as a plasma marker for Parkinson's disease identified by a proteomic approach

OBJECTIVES

Parkinson's disease (PD) ranks the second among the neurodegenerative disorders. Proteins involved in Parkinson's disease (PD) have been investigated but none as the diagnostic markers in blood.

DESIGN AND METHODS

In this study, we applied a proteomic strategy, by utilizing two-dimensional electrophoresis and mass spectrometry, to analyze two sample pools of plasma from the healthy individuals and PD subjects.

RESULTS

IgGκL and human serum amyloid P component (SAP) were found differentially expressed between these pools. SAP level increased by approximately 5-fold in PD samples, and the ELISA procedure revealed a significant (P<0.001) increase in SAP concentration (65.9 ± 18.7μg/mL) in the plasma of PD subjects (healthy individuals, 35.0 ± 12.5μg/mL), with sensitivity of 94.1% and specificity of 87.5%.

CONCLUSION

Our results indicated a potential feasibility of plasma SAP as a marker to approach PD.

Serum amyloid A and P protein levels are lowered by dextran sulfate cellulose low-density lipoprotein apheresis

The present study describes the short-term effect of dextran sulfate cellulose (DSC) low-density lipoprotein (LDL) apheresis using a plasma separator equipped with a polysulfone (PS) membrane filter (PS/DSC-LDL apheresis) on the serum amyloid A (SAA) and P (SAP) protein levels during treatment in a patient with familial hypercholesterolemia (type IIa, heterozygote). PS/DSC-LDL apheresis markedly lowered both the SAA (reduction percentage, 84.1+/-8.2%) and SAP (91.4+/-5%) levels, which returned to their respective initial levels within 4 days. Experimentally, the levels of both proteins also decreased on passage through the DSC minicolumn without a PS membrane, indicating that the DSC resin had an affinity to both proteins. These results suggest that PS/DSC-LDL apheresis may be advantageous for amyloid protein accumulating disorders, including amyloidosis and atherosclerosis.

Characterization of proteoglycans and glycosaminoglycans in bovine renal AA-type amyloidosis

Highly sulfated glycosaminoglycans (GAG) or proteoglycans (PG), especially heparan sulfate (HS) and heparan sulfate proteoglycan (HSPG), are considered to be intimately associated with amyloid deposits in different types of amyloidosis. Based on this relationship an important role for HS has been suggested in amyloidogenesis. The present immunohistological and ultrastructural study shows that in bovine renal AA-amyloidosis, sulfated GAG/PG was not restricted to amyloid deposits proper and that areas without GAP/PG were also present within the amyloid. Both glomerular and papillary amyloid contained HS (PG), and the latter also contained chondroitin sulfate (CS) and dermatan sulfate (DS), suggesting a correlation between the location of the amyloid and the type of GAG/PG deposited. Amyloid P component (AP) had a distribution similar to that of HSPG, confirming their affinity-based relationship. The GAG types found ultrastructurally in amyloid fibril preparations of glomerular and papillary amyloid isolated from the same kidney, reflected the immunohistological findings. HS was shown to be the predominant GAG in all papillary amyloid fibril extracts. Taking into account the chemico-physical properties of HS, it cannot be excluded that this predominance is introduced by the purification procedure. These results suggest that the association of GAG/PG and amyloid is not necessarily mutually obligatory and that the proposed importance of GAG in amyloidogenesis is disputable.

Amyloid neuropathy: immunocytochemical localization of intra- and extracellular immunoglobulin light chains

Sural nerve specimens from ten patients with amyloidosis (hereditary, associated with lymphoproliferative disorders, or of unknown origin) and peripheral neuropathy were investigated by immunohistochemistry at the light and electron microscopic level. Peroxidase-antiperoxidase and immunogold techniques were applied to glutaraldehyde-fixed, osmicated and epoxy-embedded tissue. In five cases, four of which associated with lymphoproliferative disorders, amyloid deposits strongly and exclusively reacted with antibodies to kappa or lambda light chains, respectively. By electron microscopy, bundles of immunogold-labelled amyloid fibrils could be identified in coated and uncoated single membrane-bound vesicles of endoneurial macrophages. Schwann cells did not contain intracellular amyloid but their processes were entangled in amyloid fibrils and their basement membranes were sometimes fused with the fibrillar masses. It is concluded that immunoglobulin light chains in AL (amyloid of immunoglobulin light chain origin) amyloidosis precipitate, forming amyloid fibrils, in the presence of, and presumably with the assistance of, endoneurial cells. Inefficiency of phagocytosis appears to be one of the major causes for the deleterious effects of amyloid.

Calcium-dependent polymerization of human serum amyloid P component is inhibited by heparin and dextran sulfate

The calcium-dependent polymerization of human serum amyloid P component (SAP) was spectrophotometrically monitored in 0.15 M NaCl at pH 7.5. The rate of the polymerization depended on the concentrations of SAP and Ca2+. It was shown for the first time that the calcium-dependent polymerization of SAP was inhibited by some sulfated polysaccharides. Most potent inhibitors were heparin and high molecular weight dextran sulfate of Mr 1.0.10(6). The inhibitory activity of glycosaminoglycans is accordant to their binding affinity for SAP, which was reported previously (Hamazaki, H. (1987) J. Biol. Chem. 262, 1456-1460). The polymerized SAP was reversibly dissociated by heparin and high molecular weight dextran sulfate. The results suggest that heparin and high molecular weight dextran sulfate may be a useful dissociating agent of polymerized SAP in amyloid deposits.

Murine tissue macrophages synthesize and secrete amyloid proteins different to amyloid A (AA)

We recently demonstrated that serum amyloid A (SAA) gene expression can be induced in extrahepatic sites with exception of the brain. Furthermore we demonstrated that tissue macrophages express SAA-gene constitutively and that SAA-gene expression can be increased by endotoxin. Until now the protein corresponding to the SAA-specific mRNA contained in macrophages has not been identified. We compared proteins precipitated from endogenously labelled samples by three antisera against amyloid A (AA) raised in different laboratories. Radiolabelled samples were derived from murine hepatocyte cultures, from cell-free translation of acute phase liver RNA or hepatocytes RNA and from peritoneal macrophages as well as Kupffer cells. All three antisera recognize a protein of 12.5 kDa Mr produced by hepatocytes (SAA), and a major protein of 14.3 kDa Mr contained in the cell-free translation products; this is the precursor of the mature SAA as demonstrated by cleavage experiments with canine pancreas microsomal enzymes. The antisera also recognize two proteins--a major one of 14.5 kDa Mr and a second of 12.5 kDa Mr contained in the supernatants and cell lysates of liver and peritoneal macrophages. New antisera raised against the two proteins do not recognize any protein, either of hepatocyte or of cell-free translation samples; they specifically precipitate two proteins from macrophage samples with the same molecular mass as that of the proteins precipitated by the anti SAA antisera. Murine acute phase sera do not react with the new antisera. However, amyloid deposits of amyloidotic mice specifically react with the new antisera. We describe two new components of murine amyloid produced by tissue macrophages.

Pathology of dysproteinemia: light chain amyloidosis, non-amyloid immunoglobulin deposition disease, cryoglobulinemia syndromes, and macroglobulinemia of Waldenström

This review has dealt with four syndromes associated with dysproteinemia, and has emphasized studies of the tissue deposits and forms of tissue injury which occur in such patients. However, similar tissue deposits and tissue damage occasionally occur in the absence of a serum or urine paraprotein, in which case other clinical data are necessary to suggest the need for examination of tissue for Ig heavy and light chain determinants in order to provide a correct diagnosis of dysproteinemia. In such cases, one may speculate that there is a low rate of paraprotein production and secretion, in addition to tissue tropism. Some paraproteins are antibodies, in which case they may circulate and/or deposit as immune complexes, or bind to tissue antigens with immune complex formation in situ. Some paraproteins are also cryoproteins, and clues to this property can also be found in the tissue, particularly at the ultrastructural level. Thus, a wide spectrum of clinical manifestations of a B cell proliferative disorder may be associated with any of a variety of circulating paraproteins and a variety of forms of tissue deposit and injury. Consequently, the best understanding of an individual patient requires correlation of the clinical features of the disorder, the immunochemical characterization of the circulating and excreted paraproteins, and an immunohistochemical analysis of the tissue deposits and associated morphologic abnormalities. This should be correlated with histologic and immunohistologic assessment of bone marrow, looking for overt B cell neoplasia, the more difficult to define "lymphoproliferative disorders," or alterations in kappa to lambda plasma cell ratios which may correlate with the deposited material. Studies of the Ig synthesized by cultured bone marrow plasma cells, and biochemical analyses of the deposited material, have demonstrated structural abnormalities of paraproteins which may be responsible for their tissue deposition.

Demonstration and classification of amyloidosis in needle biopsies of the kidneys, with special reference to amyloidosis of the AA-type

To examine whether sequence-specific antibodies directed against serum amyloid A were useful in the demonstration and classification of amyloidosis, needle biopsy specimens from the kidneys of 152 cases with renal disorders were investigated using the avidin-biotin-peroxidase complex technique of immunohistochemistry. A distinct immunoreactivity of protein AA was seen in biopsies from all 42 individuals who were clinically classified as having the AA-type of amyloidosis. The stained areas coincided with deposits stained by Congo red. Four of these cases demonstrated immunoreactivity of both protein AA and light immunoglobulin chains and all biopsies except one showed immunoreactivity for the amyloid P-component. After treatment with potassium permanganate, the amyloid deposits in the biopsies of all 42 cases lost their affinity for Congo red. Ten patients with clinical and laboratory findings compatible with the AL-type of amyloidosis were also investigated. All their biopsies demonstrated Congophilic amyloid deposits but none of them showed any immunoreactivity of protein AA. Amyloid deposits of lambda light immunoglobulin chains-but not kappa-were demonstrated in biopsies from four patients. The amyloid P-component was found in biopsies from six individuals and positive Congo red staining after treatment with potassium permanganate was seen in biopsies from four of the cases. Biopsies of 100 patients suffering from non-amyloid renal disorders were also examined. None of them displayed any immunoreactive deposits of protein AA. The investigation shows that amyloid deposits of the AA-type can be identified in needle biopsies when sequence-specific antibodies against serum amyloid A are used in the avidin-biotin-peroxidase complex technique. Both the diagnostic sensitivity (42 of 42) and specificity (110 of 110) of the assay were optimal (1.0). The method was found to be superior to other investigated techniques and useful for classifying amyloidosis in formalin-fixed renal biopsies.

The prevalence of renal amyloidosis of the AA-type in a series of 1,158 consecutive autopsies

To determine the prevalence of renal amyloidosis of the AA-type in a defined population, formalin-fixed specimens from the kidneys of all the cases autopsied in 1983 at The General Hospital of Malmö, Sweden, were investigated using immunohistochemical techniques. Amyloid deposits of protein AA were found in 10 of 1,158 investigated cases and the calculated prevalence was 0.86 per cent. The mean age at death of the individuals with the AA-type of amyloidosis was 79 years. Six of the cases with amyloidosis had rheumatoid arthritis. The avidin-biotin-peroxidase complex technique was found to be superior to the immunofluorescence method and a high sensitivity and specificity was achieved when sequence-specific antibodies against a synthetized nonapeptide corresponding to a hydrophilic segment of the polypeptide chain of protein AA were used in the assay. Nine cases with other types of amyloid deposits in the kidneys were also detected. None of these cases showed any AA immunoreactivity but all of them demonstrated Congophilic deposits which were immunohistochemically stained by antibodies against the amyloid P-component. The prevalence of renal amyloidosis comprising all types of amyloid protein deposits was 1.64 per cent.

Immunohistochemical demonstration of vitronectin in association with elastin and amyloid deposits in human kidney

The multifunctional glycoprotein vitronectin, also called serum spreading factor and S-protein of complement, is a potent inducer of cell adhesion and spreading in vitro, and also has a regulatory function in the complement and coagulation pathways. It is present both in plasma and tissue. Recently, vitronectin immunoreactivity was demonstrated in the elastic fibres of normal human skin. Normal and amyloid kidney tissue was investigated for vitronectin immunoreactivity using polyclonal and monoclonal antibodies in an avidin-biotin-peroxidase complex technique and in an alkaline phosphatase anti-alkaline phosphatase complex technique. Vitronectin was found in the elastic layers of normal vessel walls, and in glomerular sclerotic lesions in cases of benign nephrosclerosis, but not in normal glomeruli. Strong specific vitronectin immunoreactivity was found in the amyloid deposits in kidneys from cases with amyloid A type amyloidosis, and in cases with amyloid light chain type amyloidosis. Structures immunostainable with anti-amyloid A antiserum were invariably immunostainable with anti-vitronectin. An antiserum against serum amyloid P component stained the same structures as did the anti-vitronectin antibodies, and in addition stained normal glomerular basement membranes. In conclusion, vitronectin immunoreactivity was demonstrated in elastic tissue, in amyloid deposits and in sclerotic lesions in human kidney.

Pathological Society of Great Britain and Ireland. 154th meeting, 7-9 January 1987. Synopses of papers

The transformation of serum proteins into Congo red-sensitive fibrillar material is requisite for the onset and progression of amyloid disease. All the mechanisms which lead to the disease itself have not been elucidated, but our knowledge has increased significantly. It is apparent that in all types of amyloid fibrils, three common features are displayed by the major protein constituents. These are that the fibril protein has a serum precursor, a high degree of anti-parallel beta-sheet conformation and a distinctive ultrastructure on electron microscopy. In the AL and AA forms of amyloidosis, the putative precursors appear to undergo limited degradation to form the protein component of amyloid fibrils. It has been suggested that there may be certain primary structural characteristics inherent in precursor molecules which make them amyloidogenic, thus predisposing them to amyloid fibril formation. This would include certain subtypes of immunoglobulin light chains, possibly kappa I and lambda VI, in the AL type of amyloidosis and one of the polymorphic SAA species, SAA2, which has been identified as the predominating isotype found in AA amyloid fibrils. In AH amyloidosis, the mechanism of amyloid fibril formation appears to be simply a concentration phenomenon where elevated concentrations of B2-M are not handled normally and amyloid deposition is the result. Amyloidogenesis in the hereditary form of systemic amyloidosis may involve other factors in addition to the presence of a variant precursor prealbumin as indicated by the delayed onset of the disease. It is evident that the elucidation of the mechanism(s) which governs the onset and progression of the amyloidoses will allow future regulation and treatment of these all too often complex disorders.

Characterization of different amyloids with immunological techniques

We studied 71 cases of amyloidosis from the autopsy material of our institute. 17 cases were secondary amyloidosis of which 7 had initially been diagnosed as primary amyloidosis; all cases reacted positively with an anti-substance A antibody; 13 showed a suppression and 4 a strong reduction of the Congo red staining following tissue incubation in KMnO4. 25 cases were identified as primary amyloidosis of which 7 had initially not been recognized as such. In 16 cases amyloid deposits reacted positively with antibodies specific for the light chains of the immunoglobulins (3 X kappa, 13 X lambda). A monoclonal plasmacytic cell proliferation in the bone marrow was seen in 14 cases. In all cases deposits were KMnO4 resistant, but 1 case showed a slight reduction of staining intensity. 27 cases were cardio-vascular (senile) amyloidosis; in 20 cases at least 3 organs showed deposits; 12 cases had deposits in 5 and more organs. 2 cases were heredofamilial amyloidosis. In those 29 cases deposits reacted positively with an anti-prealbumin antibody, but were negative for AA and the light chains of the immunoglobulins; the Congo red staining remained strong in all cases when previously incubated in KMnO4. KMnO4-Congo red staining and antisera specific for AA, L-chains and prealbumin proved of value for classification of amyloidosis and for its organ distribution.