Blockage of amyloid induction by colchicine in an animal model

The relation between C-reactive protein and serum amyloid A in patients with autoinflammatory diseases

BACKGROUND

Autoinflammatory diseases are rare disorders of the innate immune system characterized by fever and other signs of inflammation. A feared complication of autoinflammatory diseases is the development of AA amyloidosis. AA amyloidosis is caused by extracellular deposition of soluble serum amyloid A (SAA) proteins as insoluble amyloid fibrils leading to organ damage. Prolonged high levels of SAA are a prerequisite to develop AA amyloidosis. Since measurement of SAA is relatively expensive and sometimes unavailable, C-reactive protein (CRP) is often used as a surrogacy marker to test for inflammation.

OBJECTIVE

The aim of this research is to evaluate the possible relation between CRP and SAA.

METHODS

A retrospective cohort of patients with autoinflammatory diseases (n = 99) where SAA and CRP blood testing was performed in the period between 2015 and 2021 in the University Medical Centre in Groningen was used to investigate the correlation between CRP and SAA.

RESULTS

CRP and SAA have a high correlation (rho = 0.755, p < 0.001). A CRP value below 0.45 mg/L results in 100% sensitivity for SAA below 4 mg/L. CRP below 5 mg/L is a good predictor of SAA below 4 mg/L with 85.4% sensitivity and 83.6% specificity. Only prednisone and erythrocyte sedimentation rate (ESR) significantly influence the relation between CRP and log₁₀SAA.

CONCLUSION

There was a significant correlation between CRP and SAA in our retrospective cohort. CRP levels below 5 mg/L proved to be highly predictive of SAA levels below 4 mg/L. This may not be true for patients on steroids.

An efficient combinatorial synthesis of allocolchicine analogues via a triple cascade reaction and their evaluation as inhibitors of insulin aggregation

A controlled cascade: A divergent, diastereoselective and efficient one-pot synthesis of allocolchicinoids via a cascade Suzuki-Michael addition-Carbocyclization sequence is described. The utility of the compounds as possible inhibitors of insulin aggregation is also presented.

Expression of ASC in renal tissues of familial mediterranean fever patients with amyloidosis: postulating a role for ASC in AA type amyloid deposition

Familial Mediterranean fever (FMF) is characterized by recurrent attacks of fever and serositis; in some cases, ensuing amyloidosis results in kidney damage. Treatment with colchicine reduces the frequency and severity of FMF attacks and prevents amyloidosis, although the mechanisms behind these effects are unknown. Pyrin, the protein product of the MEFV gene, interacts with ASC, a key molecule in apoptotic and inflammatory processes. ASC forms intracellular speck-like aggregates that presage cell death. Here we show that cell death after ASC speck formation is much slower in nonmyeloid cells than in myeloid cells. Additionally, we demonstrate that colchicine prevents speck formation and show that specks can survive in the extracellular space after cell death. Because we also found that ASC is expressed in renal glomeruli of patients with FMF but not in those of control patients, we posit that high local ASC expression may result in speck formation and that specks from dying cells may persist in the extracellular space where they have the potential (perhaps in association with pyrin) to nucleate amyloid. The fact that speck formation requires an intact microtubule network as shown here could potentially account for the ability of prophylactic colchicine to prevent or reverse amyloidosis in patients with FMF.

Suppression of amyloidogenesis in a mouse model by corticosteroid intervention

Steroid treatment of amyloidosis was studied previously in human and murine models of reactive amyloidosis but with limited success and with conflicting results. To determine whether steroids may inhibit amyloidogenesis, and to study factors that may play a role in this effect, the authors induced amyloidosis in Swiss male mice, using the enhanced protocol with a single intravenous injection of amyloid-enhancing factor (AEF) and 3 successive daily subcutaneous AgNO(3) injections. Suppression of amyloid formation by various commonly used steroid preparations was evaluated from the amount of splenic amyloid, using the crush-and-smear technique. All steroid preparations examined were found to suppress amyloidogenesis but with differences between them in the degree and duration of inhibition. In general, hydrocortisone and dexamethasone had the highest suppressive effect, whereas methylprednisolone displayed lower activity for shorter duration. Single-dose experiments revealed that steroid effect is limited to the onset of amyloidogenesis. These experiments show that corticosteroids may significantly suppress amyloidogenesis but only briefly and, therefore, discourage a long-term and late use of steroid supplement in different anti-amyloid treatment protocols.

Phased Fiber Growth in a Peptide Conjugate: Aggregation and Disaggregation Studies

A glycine-rich, short pentapeptide conjugate 6, derived from the highly conserved copper-binding octarepeat region of the prion protein, exhibits a tendency to self-aggregate in a time-dependent fashion. Aging of 6 afforded an insight into the phased growth of spherical prefibrillar structures to fibers of long persistence length, as observed by a combination of microscopic techniques. Interestingly, growth of these fibers was inhibited by colchicine, a known inhibitor of microtubule polymerization in a concentration dependent fashion. This study offers an intriguing insight into the occurrence of prefibrillar intermediates on the path to the formation of full length peptide fibers. It is also envisaged that constructs such as 6 may also serve as simple models to study chemical intervention of protein aggregation.

Inhibition of the second phase of amyloidogenesis in a mouse model by a single-dose colchicine regimen

Amyloidogenesis consists of two stages. In the first, amyloid enhancing factor (AEF) is generated, and in the second, deposition of amyloid fibrils occurs. Colchicine is a known inhibitor of amyloidosis of familial Mediterranean fever (FMF) and of mouse experimental amyloidosis, but the timing and mechanism of its effect are still unclear. The aim of this study is to determine whether colchicine inhibits the second phase of amyloidogenesis and to study the time correlate of such an effect. To that end, amyloid was induced in Swiss male mice with AEF and AgNO(3) (an inflammatory stimulus), a method that skips the first phase of amyloidogenesis. Two amyloid induction protocols were used: a standard protocol, in which AEF and AgNO(3) were administered concurrently, and a prolonged protocol, in which the administration of AgNO(3) was delayed by 24 hours or 7 days. To study the inhibitory effect of colchicine on the second phase of amyloidogenesis, a single dose of colchicine (30 microg) was injected intravenously before, during, or after administration of AgNO(3) in both the standard and prolonged amyloid induction protocols. The amount of amyloid deposition in the spleens was determined with the crush-and-smear technique and a 5-grade scale. Colchicine was found to inhibit the second phase of amyloidogenesis. Its best effect was achieved when administered 48 hours after initiation of AgNO(3) injections. The pattern of colchicine-inhibition-in-time in the standard and the prolonged amyloid induction protocols was similar, indicating that colchicine exerts inhibition through its effect on the inflammatory stimulus (AgNO(3)). These findings suggest that (1) colchicine suppresses amyloidogenesis in the late (second) stage and that (2) this suppression is possibly related to the anti-inflammatory effect of colchicine.

Pilot tolerability studies of hydroxychloroquine and colchicine in Alzheimer disease

Anti-inflammatory drugs may be useful in the treatment of Alzheimer disease (AD). In preparation for therapeutic trials, we conducted pilot feasibility studies of hydroxychloroquine alone and in combination with colchicine in subjects with AD. A total of 20 subjects with probable AD were treated with hydroxychloroquine 200 mg twice daily for 11 weeks, or hydroxychloroquine 200 mg twice daily plus colchicine 0.6 mg twice daily for 12 weeks; subjects were monitored for adverse medical, cognitive, or behavioral effects. Neither regimen caused adverse effects on cognitive or behavioral assessment scores. There were no significant side effects in subjects receiving hydroxychloroquine alone; 2 subjects receiving the two drugs together experienced diarrhea. We conclude that these regimens of anti-inflammatory therapy are well tolerated in subjects with AD, indicating the feasibility of large-scale therapeutic trials of these agents.

[Treatments for amyloidosis beyond symptomatic care]

INTRODUCTION

Amyloid syndromes are pathogenetically different, each of the various amyloid diseases requiring specific treatment. Unfortunately, those treatments are often preventive and symptomatic, some efficient therapies being limited to particular types of amyloidosis.

CURRENT KNOWLEDGE AND KEY POINTS

Colchicine is effective in the prevention of amyloidosis due to familial Mediterranean fever but is less or not effective in other situations. Cytotoxic agents are useful in the treatment of AL amyloidosis with or without hemopoietic stem cell transplantation. Liver transplantation is indicated for familial polyneuropathy and kidney transplantation for dialysis-related beta 2 microglobulin amyloidosis.

FUTURE PROSPECTS AND PROJECTS

In vivo binding of serum amyloid P (SAP) (component shared by all amyloid deposits) to amyloid fibril, is a new avenue in the therapeutic approach. Development of radiolabeled SAP scintigraphy allows assessment of the disease outcome and evaluation of treatment-related effects. The various treatments that were assessed until now with the objective of curing the disease are reviewed.

Inflammation and Alzheimer disease

Inflammatory mechanisms are active in patients with Alzheimer disease. Serum elevations of acute phase proteins such as alpha 1-antichymotrypsin, along with deposition of inflammatory cytokines in the brain, suggest a "cerebral acute phase response" contributing to amyloid deposition and tissue destruction. Activated microglia possessing HLA-DR surface markers accumulate around amyloid plaques. The complement cascade leads to generation of the membrane attack complex, which may directly damage neuronal membranes. This growing body of evidence suggests that empirical trials of anti-inflammatory drugs are now appropriate to test the hypothesis that suppression of these mechanisms will slow the rate of progression of Alzheimer disease. Several drugs useful in the treatment of rheumatic diseases are candidates for study in Alzheimer disease, including glucocorticoids, antimalarial drugs, and colchicine. Pilot studies of the synthetic glucocorticoid prednisone indicate that treatment with a moderate dose is well tolerated in patients with Alzheimer disease, and suppresses serum levels of acute phase proteins. Based on this experience, a multicenter parallel-design placebo-controlled trial has been initiated with Alzheimer's Disease Cooperative Study to determine whether treatment with prednisone can slow the rate of progression of Alzheimer disease.

Effects of colchicine on the induction of ornithine decarboxylase and its gene expression by the phorbol ester tumour promoter

The activity and gene expression of ornithine decarboxylase (ODC, an indicator of tumour promotion) were induced by the phorbol ester tumour promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA), in mouse skin. In the present study, the effect of colchicine, a microtubule-disrupting agent, on ODC activity and its gene expression were investigated. On administration of colchicine (100 micrograms) intraperitoneally 1.5 h before TPA treatment, ODC activity and ODC mRNA levels stimulated by TPA were suppressed to about 52 and 64%, respectively. These results suggest the involvement of a microtubule or colchicine-sensitive substrate in the signal transduction system for gene expression.

The clinical and biochemical spectrum of hereditary amyloidosis

Familial amyloidosis, once described as a puzzling and highly unusual form of polyneuropathy, is now recognized to be a collection of familial diseases with usually autosomal-dominant inheritance and widespread ethnic distribution. Familial amyloidosis occurs throughout the world and encompasses an extremely broad spectrum of clinical manifestations. In some families, progressive peripheral neuropathy dominates the illness, while in others, renal failure, ocular amyloid deposits, cardiac decompensation, or intracranial hemorrhage is the most significant clinical feature. The Portuguese (type I) and the Iowa (type III) neuropathies characteristically begin with lower limb involvement, while in the Indiana (type II) form, upper limb neuropathy is seen first; in the Japanese families with familial amyloid polyneuropathy, symptoms first become evident around age 40, whereas in the Texas family, onset is in the seventh decade. The prognosis for the different families is highly variable. Current classification of the familial amyloid polyneuropathy syndromes is based on their characteristic clinical presentations, but ongoing biochemical identification of the protein composition of amyloid substance in each form will make a more rational nosology feasible in the near future. To date, no therapy has been shown to arrest or reverse the progressive accumulation of amyloid deposits in most forms of familial amyloidosis. Familial Mediterranean fever is a major exception, and the incidence of amyloidosis associated with this disease has been dramatically reduced by the widespread prophylactic use of colchicine. Technology currently available permits the reliable identification of asymptomatic relatives at risk for developing amyloid neuropathy as well as the prenatal identification of carriers of the mutant transthyretin gene. These strategies can be used in genetic counseling aimed at reducing the continued propagation of the mutant gene.

Colchicine therapy of the renal amyloidosis of ulcerative colitis

Two patients with severe proteinuria, due to renal amyloidosis complicating chronic ulcerative colitis, improved remarkably with colchicine therapy. One patient with an initial daily urine protein excretion of 13.70 g had a reduction within 2 mo to 6.50 g and to 0.37 g after 9 yr. The other patient's daily urine protein excretion was 9.00 g. This was reduced to 5.10 g/day within 3 mo and was 0.53 g/day by 8 mo. Renal function remained stable or improved during the period of therapy. Colchicine resulted in rapid and prolonged benefit for these patients, despite their amyloid-induced nephrotic syndrome.

Behçet's disease associated with amyloidosis in Turkey and in the world

The association of amyloidosis with Behçet's disease has infrequently been reported in published works. Twenty four such cases have been observed in the world, of which 12 are from Turkey, including eight of ours. In all our eight cases renal biopsy showed amyloidosis of type AA. Behçet's disease of male preponderance, long duration, complete type, multiple organ involvement, and positive skin pathergy test were the main characteristics of all 24 cases of Behçet's disease with amyloidosis. We conclude that amyloidosis associated with Behçet's disease is a secondary AA amyloidosis occurring as an intrinsic manifestation of Behçet's disease.

Survival of patients with primary (AL) amyloidosis. Colchicine-treated cases from 1976 to 1983 compared with cases seen in previous years (1961 to 1973)

Primary amyloidosis has a variable course, but is generally associated with a short life expectancy. To date, no specific therapy has been available. Fifty-three patients with AL amyloidosis seen between 1976 and 1983 were treated with colchicine, and their clinical course and survival were compared with that in 29 other patients seen between 1961 and 1973. Of the variables measured, the treatment, the patient's sex, and the time interval from diagnosis to referral of treatment were significantly associated with length of survival. Median survival for the colchicine-treated patients was 17 months, compared with six months for the non-colchicine-treated patients. A surprising finding was the longer life span in female patients (median eight months versus four and a half months in the non-colchicine-treated group, and 25.5 months versus 10 month in the colchicine-treated group). The study suggests that colchicine has improved the life expectancy in AL amyloidosis. Although it is not a specific therapy, it may be a reasonable form of adjunctive treatment in this complex disorder.

Treatment of AL amyloidosis with melphalan, prednisone, and colchicine

Seven patients with immunoglobulin type (AL) amyloidosis were treated with combination chemotherapy, including melphalan, prednisone, and colchicine. Two patients died within 5 months of the beginning of therapy. Both had amyloid cardiomyopathy. Five patients were alive 17-60 months after the start of therapy, and none had shown progression of disease. The most significant findings were the resolution of the nephrotic syndrome in 2 patients, and improvement of liver function, as demonstrated by excretion of indocyanine green, in 2 patients. These results are encouraging and support the need for further studies of this regimen of combination chemotherapy for patients with AL amyloidosis.

Colchicine in the prevention and treatment of the amyloidosis of familial Mediterranean fever

To determine whether colchicine prevents or ameliorates amyloidosis in patients with familial Mediterranean fever, we followed 1070 patients with the latter disease for 4 to 11 years after they were advised to take colchicine to prevent febrile attacks. Overall, at the end of the study, the prevalence of nephropathy was one third of that in a study conducted before colchicine was used to treat familial Mediterranean fever. Among 960 patients who initially had no evidence of amyloidosis, proteinuria appeared in 4 who adhered to the prophylactic schedule and in 16 of 54 who admitted non-compliance. Life-table analysis showed that the cumulative rate of proteinuria was 1.7 percent (90 percent confidence limits, 0.0 and 11.3 percent) after 11 years in the compliant patients and 48.9 percent (18.8 and 79.0 percent) after 9 years in the noncompliant patients (P less than 0.0001). A total of 110 patients had overt nephropathy when they started to take colchicine. Among 86 patients who had proteinuria but not the nephrotic syndrome, proteinuria resolved in 5 and stabilized in 68 (for more than eight years in 40). Renal function deteriorated in 13 of the patients with proteinuria and in all of the 24 patients with the nephrotic syndrome or uremia. We conclude that colchicine prevented amyloidosis in our high-risk population and that it can prevent additional deterioration of renal function in patients with amyloidosis who have proteinuria but not the nephrotic syndrome.

Primary systemic amyloidosis. Comparison of melphalan/prednisone versus colchicine

This is the first prospectively randomized study of the use of melphalan/prednisone and colchicine in the treatment of primary systemic amyloidosis. One hundred one patients were stratified according to their dominant clinical manifestation. Forty-nine patients initially received melphalan/prednisone and eight subsequently had colchicine added to their regimen. Fifty-two patients initially received colchicine and 35 subsequently required melphalan/prednisone because of progressive disease. There was no difference in survival when the two groups were analyzed in aggregate (melphalan/prednisone, 25.2 months versus colchicine, 18 months; p = 0.23). When the survival of patients receiving only one regimen was analyzed or when survival was analyzed from the time of entry into the study to the time of death or progression of disease, significant differences (p less than 0.001 and p less than 0.0001, respectively) were evident, favoring melphalan/prednisone. This study suggests that melphalan/prednisone is superior to colchicine in the treatment of primary amyloidosis, but to confirm this impression, a study without a crossover group is necessary.

Ascorbic acid-induced regression of amyloidosis in experimental animals

Ascorbic acid was found to accelerate amyloid degradation in an experimental animal model. Based on experiments in vitro which demonstrated the ability of ascorbic acid to restore the amyloid-degrading activity of amyloidotic human serum, the effect of orally administered ascorbic acid was tested in casein-induced murine amyloidosis. Histopathological examination of splenic tissue of mice killed at different times after the termination of the amyloidogenic stimulus showed a markedly decreased amyloid deposition in ascorbic acid-treated animals as compared to the controls. The effect of ascorbic acid was to a certain degree dose-dependent. Colchicine blocked amyloid synthesis when administered during amyloid induction. In animals which were given the drug during the post-induction period it had no effect. The amyloid-degrading activity of mouse serum was reduced in amyloidotic mice. Administration of ascorbic acid partially restored the amyloid-degrading activity of these animals.

Vertebral rim lesions in dorsolumbar spine

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Colchicine in systemic amyloidosis

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DMSO and colchicine therapy in amyloid disease

There is no specific therapy for primary amyloidosis, and acquired generalised amyloidosis can be treated only if the underlying disease is eliminated. In this study we have investigated the role of colchicine therapy in primary amyloidosis, and dimethylsulphoxide (DMSO) in leprosy associated secondary amyloidosis. No effect on creatinine clearance or 24 h proteinuria could be observed in the patients with primary amyloidosis. In the DMSO group renal function was considerably improved in 3 patients with moderate renal failure but not in those with severe renal impairment (creatinine clearance less than 10 ml/min). Serum SAA determinations were not particularly informative. These findings point to a beneficial effect of DMSO in human secondary amyloidosis when given at an early stage of renal involvement.

Gastrointestinal amyloidosis complicating psoriatic arthropathy

A patient is described who developed gastrointestinal amyloidosis complicating psoriatic arthropathy. The presenting symptom was progressive dysphagia due to oesophageal involvement. Other clinical features included gastric ulceration with melaena, intestinal pseudo-obstruction and evidence of impaired renal function. The oesophageal symptoms improved after endoscopic dilatation of the cardia. Colchicine was used in an attempt to slow down progression of the condition.

Amyloidosis in children with familial Mediterranean fever

The clinical and laboratory findings of 35 children with familial Mediterranean fever who developed amyloidosis are described. The types, frequency, and severity of attacks of familial Mediterranean fever in these children were no different from patients with this disease without amyloidosis. Although amyloid was widely deposited in all tissues, the major clinical manifestations of the amyloidosis were proteinuria, the nephrotic syndrome, and progressive renal failure. Only 20% of the patients were alive 5 years after the first appearance of proteinuria.

Gout and amyloidosis

Two patients with gout and amyloidosis are reported. In contrast with other forms of chronic arthritis gout is apparently not associated with an increased incidence of amyloidosis. The possible reasons for this exception are discussed.

Suppression and acceleration of experimental amyloidosis in mouse model

Leupeptins, protease inhibitors, suppress the appearance of experimental amyloidosis in CBA mice induced by the injections with complete Freund's adjuvant. This substance, however, should be administered continuously from 1 week prior to amyloid induction to the end of the experiment. On the other hand, Trypan blue, inhibitors of lysosomal enzymes, accelerates experimental amyloidosis in the mouse model above-mentioned. Trypan blue is effective when given either prior to or at the same time of the initiation of amyloid induction. Organic Germanium has not been confirmed to be a potent suppressor of experimental murine amyloidosis but the experimental group administered this substance continuously from 1 week prior to the induction shows a rather low incidence of amyloidosis, and the average number of amyloidotic organs per affected mouse is about half of that of the control group. The suppression and acceleration of experimental murine amyloidosis presented here are a useful tool for investigating the pathogenesis of amyloidosis.

Differences in the acute phase responses of serum amyloid P-component (SAP) and C3 to injections of casein or bovine serum albumin in amyloid-susceptible and -resistant mouse strains

In CBA/Ca and C57Bl/Cbi mice, which are susceptible to casein-induced amyloidosis, daily injections of casein caused a marked rise in the level of circulating serum amyloid P-component (SAP), which was sustained while injections continued. In contrast, mice given bovine serum albumin (BSA) injections showed only a small, transient increase in SAP levels. A/J mice, which are relatively resistant to casein-induced amyloidosis, also developed high SAP levels initially, but the increase was not maintained despite continued administration of casein. A/J mice receiving BSA had a slowly progressive rise in SAP which reached the same level as in the casein-treated animals. Administration of colchicine, which prevents casein-induced amyloidosis, suppressed the SAP response to casein in CBA mice. The serum level of the C3 component of complement, which is not an amyloid protein but is an acute phase reactant, also increased following casein injection. The rise in C3 was, however, proportionately less than that of SAP, was less sustained and was scarcely affected by colchicine. The present results therefore demonstrate different patterns in the acute phase response of different proteins in different mouse strains, and suggest that there may be a relationship between sustained high levels of SAP and the deposition of amyloid.

Binding of serum amyloid P-component (SAP) by amyloid fibrils

Serum amyloid P-component (protein SAP) was found to bind in vitro to isolated amyloid fibrils of both primary and secondary types. The binding was strictly calcium-dependent, optimal uptake requiring at least 0.5 mM calcium ion. Using normal human serum as the source of protein SAP different fibril preparations became saturated with between 5--20 micrograms of SAP per mg dry weight of fibril. Isolated pure protein SAP bound in greater amounts. In control experiments SAP did not bind significantly to collagen fibrils, sheep erythrocytes, plastic shavings, or the following immobilized proteins: human kappa or lambda Bence-Jones proteins; human; rabbit or mouse IgG; human serum albumin. C-reactive protein, which resembles protein SAP structurally but has calcium-dependent specificity for different ligands, bound significantly to only one of five different amyloid fibril preparations.

The pineal and regulation of fibrosis: pinealectomy as a model of primary biliary cirrhosis: roles of melatonin and prostaglandins in fibrosis and regulation of T lymphocytes

Pinealectomy leads to increased formation of fibrous tissue in the abdominal cavity, increased skin pigmentation and elevated cholesterol and alkaline phosphatase levels. It also leads to reduced formation and/or action of prostaglandin (PG) E1 and thromboxane (TX) A2. PGE1 plays an important role in enhancing function of T suppressor lymphocytes which control overactive antibody-producing B lymphocytes. In primary biliary cirrhosis there are increased skin pigmentation, hepatic fibrosis, elevated cholesterol and alkaline phosphatase levels, defective T lymphocytes and hyperactive B lymphocytes. Primary biliary cirrhosis may be a pineal deficiency disease. Serotonin is important in the pineal and the serotonin antagonist methysergide may cause retroperitoneal fibrosis by interfering with pineal function. There is a good deal of other evidence which suggests that melatonin PGE1 and TXA2 are important in the regulation of fibrosis in other situations such as "collagen" diseases, lithium-induced fibrosis and cardiomyopathies. This suggests that enhancement of formation of PGE1 and TXA2 may be of value in diseases associated with excess fibrosis and defective T suppressor cell function. PGE1 levels may be raised by zinc, penicillin, penicillamine and essential fatty acids. TXA2 levels may be raised by low dose colchicine. These new approaches to treatment may prove safer and more effective than existing ones. They may be of value in disorders such as cardiomyopathy, Hodgkin's disease and other lymphomas, multiple sclerosis, Crohn's disease, atopy and other diseases in which defective T cell function is suspected.

Effects of dimethyl sulfoxide and colchicine on the resorption of experimental amyloid

The induction of amyloid in C3H mice by either casein solution or complete Freund's adjuvant emulsion with Mycobacterium butyricum was confirmed by partial splenectomy. The animals were autopsied after treatment with dimethyl sulfoxide (550 mg/kg, 50 times), colchicine (0.02 mg/kg, 15--37 times), or saline solution as a control. Detailed histological comparisons of biopsy and autopsy spleens provided evidence that dimethyl sulfoxide was significantly effective in the resorption of amyloid, while in the animals treated with colchicine amyloid deposition was increased. The effect of dimethyl sulfoxide was discussed with reference to the modification of amyloid fibrils.

Serum amyloid A: evidence for its origin in polymorphonuclear leukocytes

In this study the presence of an amyloid A, antigenically related material was determined in four subpopulations of human leukocytes. Monocytes, granulocytes, thymus-derived lymphocytes, and bone marrow-derived and null lymphocytes were isolated from the peripheral blood of five apparently normal subjects, two patients with secondary amyloidosis, three patients with acute infections, and seven patients with metastatic cancer. Mononuclear leukocytes, isolated from the interface of a Ficoll-Hypaque gradient, were separated into monocytes, thymus-derived lymphocytes, and bone marrow-derived plus null lymphocytes by glass adherence and depletion of sheep erythrocyte rosette-forming lymphocytes. Granulocytes were isolated by sedimentation in 2% methyl cellulose from the erythrocyte-rich pellet formed at the bottom of the Ficoll-Hypaque gradient. The four isolated leukocyte subpopulations were cultured and, at varying intervals, the amyloid A content of the culture medium and of sonicated, 2 x 10(6) cells was determined by radioimmunoassay. Our results indicated a 2-14 times greater amount of amyloid A-related material in the sonicated granulocytes compared with the individuals' serum amyloid A levels. The mononuclear subpopulations showed a low or negligible amyloid A content. The amount of amyloid A antigenic material was further found to increase in cultured granulocytes, reaching a peak value between the 16th and 30th h of culture. The granulocytes of only two out of eight individuals tested released amyloid A antigenically related material into the culture medium. This release was found to be blocked by the presence of colchicine, vincristine, puromycin, or cycloheximide in the culture medium. In contrast, only the presence of puromycin or cycloheximide was shown to significantly inhibit the intracellular increase of amyloid A in the cultured granulocytes. Thus, it appears that among the circulating blood cells, the granulocytes produce amyloid A antigenically related material and could release it under conditions that remain to be further defined.

New concepts in the pathogenesis of primary and secondary amyloid disease

Despite the marked progress obtained in the structural and amino acid sequencing data of amyloid proteins our understanding of the cellular mechanisms causing the deposition of amyloid fibrils is still poor. Some of the questions about the cellular events leading to the synthesis of amyloid fibrils can be approached by evaluating the immune reactivity of animals that develop amyloid after repeated daily casein injections. Recent studies carried out in a mouse model indicate that macrophage activation associated with T-cell suppression and followed by B-cell proliferation appear to be responsible for the immunopathological abnormalities in both primary and secondary amyloid disease.

Treatment of experimental murine amyloidosis with dimethyl sulfoxide

Dimethyl sulfoxide was administered intravenously for 60 days to twenty mice with casein-induced amyloidosis. Partial or total disappearance of amyloid deposits occurred in all treated animals. The urine of these animals contained a substance from which amyloid fibrils could be synthesized. A control group of mice with casein-induced amyloidosis given saline injections showed massive amyloid deposition in the liver and in the spleen at the end of the experiment. Neither the urine of these mice nor the urine of normal control mice treated with dimethyl sulfoxide contained substances from which amyloid fibrils could be synthesized. It is our assumption that dimethyl sulfoxide treatment of mice with amyloidosis resulted in a break up of amyloid fibres into small subunits which were excreted in the urine.

Colchicine inhibition of the first phase of amyloid synthesis in experimental animals

Colchicine was found to inhibit the first phase of casein-induced synthesis of murine amyloid. When mice were treated with colchicine during the first 7 days of an amyloid induction regimen or when colchicine was given to the donor mice in a transfer model, the amyloidogenic stimulus of casein was blocked completely. Amyloid synthesis was however, not interrupted by the administration of colchicine during the last 7 days of the casein regimen nor by colchicine treatment of recipient mice in a transfer model.

Murine model for human secondary amyloidosis: genetic variability of the acute-phase serum protein SAA response to endotoxins and casein

The serum precursor SAA of the secondary amyloid protein AA has been detected by solid-phase radioimmunoassay as a normal serum alpha-globulin of mol wt 160,000, which dissociates to a more stable 12,500 dalton moiety on treatment with formic acid. In 12 strains of mice, including T-cell-deficient nude mice, treated with the amyloid-inducing agents lipopolysaccharide (LPS) or casein, SAA behaved as an acute-phase reactant. SAA concentration rose to about 750 mug/ml by 24 h and returned to less than 1 mug/ml by 48 h. Since the amyloid-resistant colchicine-treated mice and AJ mice had a normal SAA response to LPS, it appears that their resistance to amyloid induction is due to the nature of their SAA processing rather than decreased SAA production. C3H/HeJ mice, which have defective B-lymphocyte responses to LPS, required extremely high dosages of LPS to cause SAA elevation, although their SAA response to casein was normal. This suggests that SAA is an acute-phase protein produced as a result of B-lymphocyte stimulation. Preliminary evidence suggests that at the height of an acute SAA response, liver homogenates are particularly rich in protein AA cross-reacting material.