Amyloid in osteoarthritic hip joints: deposits in relation to chondromatosis, pyrophosphate, and inflammatory cell infiltrate in the synovial membrane and fibrous capsule

Association between spinal stenosis and wild-type ATTR amyloidosis

Age-related cardiac amyloidosis results from deposits of wild-type tranthyretin amyloid (ATTRwt) in cardiac tissue. ATTR may play a role in carpal tunnel syndrome (CTS) and in spinal stenosis (SS), indicating or presaging systemic amyloidosis. We investigated consecutive patients undergoing surgery for SS for ATTR deposition in the resected ligamentum flavum (LF) and concomitant risk of cardiac amyloidosis. Each surgical specimen (LF) was stained with Congo red, and if positive, the amyloid deposits were typed by mass spectrometry. Patients with positive specimens underwent standard of care evaluation with fat pad aspirates, serum and urine protein electrophoresis with immunofixation, free light-chain assay, TTR gene sequencing and technetium 99 m-pyrophosphate-scintigraphy. In 2018-2019, 324 patients underwent surgery for SS and 43 patients (13%) had ATTR in the LF with wild-type TTR gene sequences. Two cases of ATTRwt cardiac amyloidosis were diagnosed and received treatment. In this large series, ATTRwt was identified in 13% of the patients undergoing laminectomy for SS. Patients with amyloid in the ligamentum flavum were older and had a higher prevalence of CTS, suggesting a systemic form of ATTR amyloidosis involving connective tissue. Further prospective study of patients with SS at risk for systemic amyloidosis is warranted.

Transthyretin amyloid deposits in lumbar spinal stenosis and assessment of signs of systemic amyloidosis

BACKGROUND

Wild-type transthyretin (ATTRwt) amyloidosis is the most common systemic amyloidosis in Western countries and manifests mainly as progressive restrictive cardiomyopathy.

OBJECTIVE

To study the prevalence of ATTR deposits in ligament tissue in patients undergoing surgery for lumbar spinal stenosis and to assess whether these deposits are associated with cardiac amyloidosis.

MATERIALS AND METHODS

A total of 250 patients, aged 50-89 (57% women), none with known cardiovascular disease, were included. Ligaments were investigated microscopically for amyloid. ATTR type was determined by immunohistochemistry and fibril type by Western blot. The amount of amyloid was graded 0-4. All patients with grade 3-4 ATTR deposits were offered cardiac investigation including ECG, cardiac ultrasound, plasma NT-proBNP and cardiac magnetic resonance (CMR), including modern tissue characterization.

RESULTS

Amyloid was identified in 221 of the samples (88.4%). ATTR appeared in 93 samples (37%) of whom 42 (17 women and 25 men) were graded 3-4; all had fibril type A (mixture of full-length TTR and fragmented TTR). Twenty-nine of 42 patients with grade 3-4 ATTR deposits accepted cardiovascular investigations; none of them had definite signs of cardiac amyloidosis, but five men had a history of carpal tunnel syndrome.

CONCLUSIONS

The prevalence of ATTR deposits in ligamentum flavum in patients with lumbar spinal stenosis was high but not associated with manifest ATTR cardiac amyloidosis. However, the findings of fibril type A, the prevalence of previous carpal tunnel syndrome and ATTR amyloid in surrounding adipose and vascular tissue indicate that amyloid deposits in ligamentum flavum may be an early manifestation of systemic ATTR disease.

Lumbosacral stenosis in Labrador retriever military working dogs - an exomic exploratory study

Background

Canine lumbosacral stenosis is defined as narrowing of the caudal lumbar and/or sacral vertebral canal. A risk factor for neurologic problems in many large sized breeds, lumbosacral stenosis can also cause early retirement in Labrador retriever military working dogs. Though vital for conservative management of the condition, early detection is complicated by the ambiguous nature of clinical signs of lumbosacral stenosis in stoic and high-drive Labrador retriever military working dogs. Though clinical diagnoses of lumbosacral stenosis using CT imaging are standard, they are usually not performed unless dogs present with clinical symptoms. Understanding the underlying genomic mechanisms would be beneficial in developing early detection methods for lumbosacral stenosis, which could prevent premature retirement in working dogs. The exomes of 8 young Labrador retriever military working dogs (4 affected and 4 unaffected by lumbosacral stenosis, phenotypically selected by CT image analyses from 40 dogs with no reported clinical signs of the condition) were sequenced to identify and annotate exonic variants between dogs negative and positive for lumbosacral stenosis.

Results

Two-hundred and fifty-two variants were detected to be homozygous for the wild allele and either homozygous or heterozygous for the variant allele. Seventeen non-disruptive variants were detected that could affect protein effectiveness in 7 annotated (SCN1B, RGS9BP, ASXL3, TTR, LRRC16B, PTPRO, ZBBX) and 3 predicted genes (EEF1A1, DNAJA1, ZFX). No exonic variants were detected in any of the canine orthologues for human lumbar spinal stenosis candidate genes.

Conclusions

TTR (transthyretin) gene could be a possible candidate for lumbosacral stenosis in Labrador retrievers based on previous human studies that have reported an association between human lumbar spinal stenosis and transthyretin protein amyloidosis. Other genes identified with exonic variants in this study but with no known published association with lumbosacral stenosis and/or lumbar spinal stenosis could also be candidate genes for future canine lumbosacral stenosis studies but their roles remain currently unknown. Human lumbar spinal stenosis candidate genes also cannot be ruled out as lumbosacral stenosis candidate genes. More definitive genetic investigations of this condition are needed before any genetic test for lumbosacral stenosis in Labrador retriever can be developed.

Electronic supplementary material

The online version of this article (10.1186/s40575-017-0052-6) contains supplementary material, which is available to authorized users.

Interleukin-6 and chondrocyte mineralisation act in tandem to promote experimental osteoarthritis

OBJECTIVES

Basic calcium phosphate (BCP) crystal and interleukin 6 (IL-6) have been implicated in osteoarthritis (OA). We hypothesise that these two factors may be linked in a reciprocal amplification loop which leads to OA.

METHODS

Primary murine chondrocytes and human cartilage explants were incubated with hydroxyapatite (HA) crystals, a form of BCP, and the modulation of cytokines and matrix-degrading enzymes assayed. The ability of IL-6 to stimulate chondrocyte calcification was assessed in vitro. The mechanisms underlying the effects of HA on chondrocytes were investigated using chemical inhibitors, and the pathways mediating IL-6-induced calcification characterised by quantifying the expression of genes involved in chondrocyte mineralisation. The role of calcification in vivo was studied in the meniscectomy model of murine OA (MNX), and the link between IL-6 and cartilage degradation investigated by histology.

RESULTS

In chondrocytes, BCP crystals stimulated IL-6 secretion, further amplified in an autocrine loop, through signalling pathways involving Syk and PI3 kinases, Jak2 and Stat3 molecules. Exogenous IL-6 promoted calcium-containing crystal formation and upregulation of genes involved in calcification: the pyrophosphate channel Ank, the calcium channel Annexin5 and the sodium/phosphate cotransporter Pit-1. Treatment of chondrocytes with IL-6 inhibitors significantly inhibited IL-6-induced crystal formation. In meniscectomised mice, increasing deposits of BCP crystals were observed around the joint and correlated with cartilage degradation and IL-6 expression. Finally, BCP crystals induced proteoglycan loss and IL-6 expression in human cartilage explants, which were reduced by an IL-6 inhibitor.

CONCLUSIONS

BCP crystals and IL-6 form a positive feedback loop leading to OA. Targeting calcium-containing crystal formation and/or IL-6 are promising therapeutic strategies in OA.

Clinical and laboratory characteristics of patients having amyloidogenic transthyretin deposition in osteoarthritic knee joints

OBJECTIVE

Our aim was to investigate clinical and laboratory characteristics of osteoarthritic patients who had amyloid deposition in their knee joints.

METHODS

Synovial membranes were obtained from 36 patients with knee osteoarthritis (OA) who underwent joint replacement surgery. From this sample, the diagnosis of amyloid was determined by Congo red staining, which demonstrated apple-green birefringence under a polarized microscope. All synovial membranes were immunohistochemically characterized for the expressions of amyloid immunoglobulin light chain (AL-κ and AL-λ), serum amyloid-A (SAA), amyloidogenic transthyretin (ATTR), and amyloidogenic β2-microglobulin (Aβ2M). Matrix-assisted laser desorption-ionizaton/time of flight mass spectrometry (MALDI-TOF MS) was used to analyze transthyretin (TTR) isoforms in the serum of each patient.

RESULTS

Nine cases (25%) were found to be amyloid-positive. Immunohistochemically, eight cases (88.9%) had ATTR deposition, and one sample (11.1%) was shown to be AL-κ-positive. MALDI-TOF MS identified that the TTR in the serum of the patients was unmodified wild-type TTR, TTR-Cys-S-S-Cys, and TTR-Cys-S-S-CysGly. The age at surgery and the disease duration were significantly higher in the ATTR-positive group than in the ATTR-negative group. Knee score and function score were significantly lower in the ATTR-positive group than in the ATTR-negative group.

CONCLUSIONS

Amyloid deposition in synovial membranes of OA patients was found to be ATTR and AL-κ. TTR in the serum of the patients was unmodified wild-type TTR together with two isoforms. The high age at surgery, long disease duration, and a deteriorated knee function were associated with ATTR amyloid deposition in the osteoarthritic knee joints.

Transthyretin-derived amyloidosis: probably a common cause of lumbar spinal stenosis

BACKGROUND

Senile systemic amyloidosis (SSA) derived from wild-type transthyretin is a fairly common condition of old individuals, particularly men. The main presentation is by cardiac involvement, which can lead to severe restrictive cardiomyopathy. SSA is, however, a systemic disease, and amyloid deposits may appear in many other tissues but are thought to be without clinical symptoms outside the heart. Amyloid is a very common finding in cartilage and ligaments of elderly subjects, and transthyretin has been demonstrated in some deposits. Lumbar spinal stenosis is also a condition of usually elderly individuals in whom narrowing of the lumbar spinal canal leads to compression of nerves to the lower limbs.

RESULTS

We questioned whether lumbar spinal stenosis sometimes could be a manifestation of undiagnosed SSA. In this first report we have studied the presence of amyloid in material obtained at surgery for spinal stenosis in 26 patients. Amyloid was found in 25 subjects. Transthyretin was demonstrated immunohistochemically in 5 out of 15 studied resected tissues. Four of the positive materials were analyzed with Western blot revealing both full-length transthyretin (TTR) and C-terminal TTR fragments, typically seen in SSA.

CONCLUSION

We conclude that lumbar spinal stenosis quite frequently may be a consequence of SSA and that further studies are warranted.

Amyloid deposition in osteoarthritis of the hip

PURPOSE

The aim of this study was to examine the frequency of amyloid deposition in patients with end-stage hip osteoarthritis (OA). Further, their impact on the clinical situation and the OA severity were analyzed.

METHODS

Fifty patients with OA who consecutively underwent total hip replacement were prospectively evaluated. The X-rays of the patients were analyzed using a radiological score (Kellgren-Lawrence) to quantify the amount of radiological changes. A clinical score [Harris hip score (HHS)] was preoperatively calculated for every patient. Specimens from the femoral head of bone and cartilage, and additionally 1 cm(2) of the capsule, were obtained from every patient intraoperatively for analyzing the amyloid deposition histologically. A histological grading was also performed. On a subset of patients with amyloid deposits, the subtypes were characterized immunohistologically.

RESULTS

The only subtype of amyloid was ATTR. There was a high, significant correlation between articular amyloid deposition and the age of the patient at the time of the operation. No correlation was found for any other measured item, such as signs of inflammation in the blood samples, histological grading, radiological score or clinical score.

CONCLUSIONS

The frequency of amyloid deposits in the joint increases with age, and it can generally be considered to be of no pathologic significance, since a correlation with the radiological and histological changes was ruled out by our study. Thus, the presence of ATTR amyloid may simply be an incidental finding in aged joints.

Advanced glycation end products in intervertebral discs and hip joint capsules: correlation with senile amyloid?

Advanced glycation end-products (AGEs) may be involved in either amyloidogenesis or complications related to amyloid. The incidence of AGE increases with age as does the prevalence of amyloid affecting the hip joint capsule and intervertebral discs. We hypothesized that AGEs may be involved in the pathology of these amyloidoses and investigated the spatial and temporal relationship between AGEs and amyloid of intervertebral discs and hip joint capsules. Using immunohistochemistry, AGEs were found in all 71 intervertebral discs and all 87 hip joint capsules. Amyloid was present in 59 (83%) intervertebral discs and 65 (75%) hip joint capsules. AGEs were found in the immediate vicinity of amyloid deposits in 104 of 253 (41%) investigated amyloid deposits of the intervertebral discs and 159 of 311 (51%) investigated amyloid deposits of the hip joint capsules. However, only rarely were AGEs demonstrated within amyloid deposits. No linear correlation was found between the amount of AGEs and the amount of amyloid deposited. As AGEs are more common than amyloid in intervertebral discs and hip joint capsules, it is conceivable to suggest that AGEs might be involved in the pathogenesis of amyloid at these anatomical sites. However, the amyloid proteins appear not to be modified and AGE modification is not a general characteristic of senile amyloidoses.

Advances in the microscopy of osteoarthritis

This review describes recent contributions made by microscopy to the understanding of osteoarthritis, a clinical syndrome the pathological features of which are well defined by classical white light microscopy. The fluorescence and reflected light, conventional and scanning optical microscopy of excised osteoarthritic tissue preparations, from human and animal sources, has enabled the identification of cell proteins such as S100, of matrix components such as the proteoglycans and collagens, and of adhesion molecules including fibronectin, the integrins and tenascin. Comparable microscopic studies have been made of cell and tissue culture preparations of osteoarthritic cartilage and synovium. Scanning optical microscopy also allows the rapid measurement, in hydrated osteoarthritic tissues, of cell density, cell size, surface roughness and other parameters. The importance of water in sustaining the physical attributes of cartilage is accepted and new forms of electron microscopy can play important parts in the study of unfixed osteoarthritic cartilage. These methods include the low temperature scanning electron microscopy and electron probe x-ray microanalysis of hydrated bulk material and the high resolution transmission electron microscopy of low temperature replicas of cartilage surfaces. Understanding of osteoarthritis has been facilitated by these advances and will continue to be enhanced as new techniques of microscopy evolve.

Localized deposition of amyloid in articular cartilage

The frequency, nature and tissue distribution of localized amyloid deposits in articular cartilage of young and elderly patients, with and without evidence of arthritic disease, was determined. Localized amyloid deposits in articular cartilage were not found in young patients with osteoarthritis of the hip or chondromalacia/osteoarthritis of the patella. However, in elderly patients with osteoarthritis of the hip, amyloid deposits were commonly found, although at no greater frequency than in elderly patients with no evidence of arthritis. Amyloid deposits were commonly present (in 95% of cases) in osteoarthritis of the knee joint and in the articular cartilage of all joints containing pyrophosphate deposits. Similar deposits of amyloid were also found in the articular cartilage of 40-45% of rheumatoid joints. These findings indicate that localized amyloid deposits in the articular cartilage are largely age-related and not due to specific pathological alterations affecting articular cartilage.

Deposition of amyloid of unknown origin in articular cartilage

Articular cartilage, obtained from the large toe during hallux valgus operations in 37 patients, was investigated for the presence of amyloid by using the Congo red staining method. Amyloid deposits were demonstrated, particularly in the superficial layer of the cartilage, in 30 cases. This amyloid did not react immunohistochemically with any of the antibodies against the known five major amyloid types (AA, A lambda, A kappa, AF, AB). From these data it is concluded that hyaline cartilage in older individuals is prone to infiltration by an amyloid of a hitherto unidentified class. From the morphological observations there seems to be no correlation between amyloid deposits and the development of osteoarthrosis.

Dystrophic amyloidosis: a local complication of tissue damage with heterogeneous distribution

Seventeen consecutive patients with dystrophic amyloidosis are reported here (eight Chinese, three Indian, three Iban, two Malay and one Caucasian). Ten were females and seven males, with ages ranging from 12 to 80 years (mean of 48 years). Five instances of dystrophic amyloidosis occurred in areas of tissue damage in the cardiovascular system, including fibrotic cardiac valves and an atheromatous plaque. Three occurred in osteoarthritic joint tissue. Of note were three occurrences in endometriotic cyst walls, four in the fibrotic walls of epidermal cysts, one in a hernial sac and one at the edge of a skin ulcer. All deposits were congophilic and exhibited green-birefringence and permanganate-resistance. Immunohistochemistry did not reveal reactivity for AA protein or immunoglobulin lambda or kappa light-chains. AP protein was detected in 35% of cases. Our results show that, besides the usual sites of osteoarthritic joints and damaged heart valves, dystrophic amyloidosis can complicate other areas of chronic tissue damage and fibrosis such as walls of cysts and ulcers. While the pathogenesis and biochemical nature remain unresolved, immunohistochemistry indicates that neither AA nor AL proteins are present in the deposits, and suggests that a different amyloid protein is involved.

[Serum level and organ deposits of beta 2-microglobulin in dialysis patients]

In radioimmunological estimation of beta 2-microglobulin (beta 2m) significant higher serum values were found in 36 dialysis patients (44.4 +/- 20.3 mg/l) in comparison with healthy probands (1.5 +/- 0.2 mg/l). A significant relation to the duration of dialysis, diuresis, symptoms of the musculo-skeletal system, but not to radiologic changes or bone biopsy findings could be seen. Post mortem examinations carried out in 21 dialysis patients revealed AB-amyloid deposits in synovial tissue of different joints (particularly shoulder and hip joint) or intervertebral discs in eight patients (age 48 to 73 years, dialysis duration less than four years) without correlation to serum beta 2m level or radiographically suspect areas. In the tissue of cervical spine or intervertebral discs of two patients suffering from destructive spondylarthropathy no amyloid could be detected. These results suggest that AB-amyloid may occur in elderly patients early in the course of hemodialysis and may be asymptomatic in most cases.

Amyloid in intervertebral discs of surgery and autopsy material. A new class of amyloid?

Intervertebral discs from 82 consecutive operations on herniation and 59 autopsies (one case with generalized amyloidosis) were studied. Amyloid deposits observed in surgical and autopsy specimens increased with age in both series. Degenerative changes were related to age and to amyloid deposits in autopsy, but not in surgical cases. Calcium pyrophosphate dihydrate deposits (often in proximity to amyloid deposits) were found in autopsy discs of six patients and in surgical specimens of three patients with previous operations on herniated discs. Antisera against amyloid fibril proteins of different types including AA-, A lambda-, A kappa, AF- and AB-types showed no reaction with disc amyloid. In one case with generalized A lambda-amyloidosis the disc amyloid was not of the A lambda-type. Based on our results, we suppose that disc amyloid is a form of localized senile amyloidosis - possibly representing a new class of amyloid limited to cartilage tissue.

beta 2-Microglobulin amyloidosis. A systemic amyloid disease affecting primarily synovium and bone in long-term dialysis patients

A number of rheumatic disorders occur in patients on long-term hemodialysis treatment. In recent years a clinical syndrome comprising carpal tunnel syndrome, destructive arthropathy, and cystic bone lesions has been recognized in these patients. Congo-red staining and microscopy in polarized light reveal a high frequency of amyloid in the affected tissues. Amino acid sequence data of the isolated major amyloid fibril protein show its identity with beta 2-microglobulin. beta 2-microglobulin amyloid has a predilection for synovial tissues and bone, but visceral deposits may also occur indicating the systemic nature of the disease. The clinicopathological features, pathogenesis, and diagnosis of beta 2-microglobulin amyloidosis are reviewed, and the therapeutic and prophylactic measures discussed. The identification of beta 2-microglobulin as an amyloidogenic protein has in an important way contributed to the understanding of the mechanisms of amyloidogenesis in general and emphasized the complexity of amyloid disease and the diversity of proteins capable of forming congophilic fibrillar deposits in human tissues.

Amyloid deposits in surgically removed articular and periarticular tissue

In tissue from 13 of 30 patients subjected to meniscectomy, amyloid degeneration was found to varying extent along the surface of the meniscus. Tissue from 30 synovectomies, 30 bursectomies and 30 ganglia showed amyloid deposits in four, six and eight cases, respectively. Amyloid was found significantly more frequently in older patients, but there was no sex difference and no relation to duration of the symptoms or to other histological changes in the tissue. Micro-deposits of amyloid in joint tissue and tissue neighbouring joints are a frequent finding, especially in elderly persons, but the clinical significance of this finding is not clear.

'Dialysis related arthropathy': a survey of 95 patients receiving chronic haemodialysis with special reference to beta 2 microglobulin related amyloidosis

Ninety five patients receiving chronic haemodialysis (CHD) were surveyed to determine the prevalence of rheumatic disease and, where possible, its aetiology. At least three distinct rheumatic syndromes were identified--a group of patients with a syndrome consisting of large and medium joint synovial swelling, restricted hips and shoulders, tenosynovitis, carpal tunnel syndrome, and bone cysts due to deposition of beta 2 microglobulin related amyloid (AM beta 2m); a second group with erosive azotaemic osteoarthropathy; and a third group with age related degenerative disease of small, large, and axial joints. The data presented suggest that in patients receiving CHD (a) the prevalence of AM beta 2m deposition and the associated syndrome increases with duration of dialysis, but in patients who have been dialysed for more than 10 years the risk of developing AM beta 2m is related to age; (b) AM beta 2m deposition in subchondral cysts, but not synovium, causes joint destruction; also, AM beta 2m may be more prone to deposition in synovium of joints already damaged by other processes; (c) in the absence of synovial iron deposition synovial AM beta 2m is not associated with an inflammatory infiltrate; (d) hyperparathyroidism and perhaps other factors such as synovial iron deposition are probably more important than AM beta 2m as causes of peripheral joint degeneration and destructive spondyloarthropathy in patients receiving CHD.

P component in the synovium in rheumatoid and osteoarthritis

P component is present in amyloid deposits, normal serum, and normal tissues in relation to elastic fibres. Its pathological role in inflammatory synovitis was investigated. Its distribution was determined immunohistologically in 33 synovia: 15 rheumatoid; seven osteoarthritic; seven traumatic controls; and four infected biopsy specimens. P component was present in two circumscribed distributions: extracellular fibrils in dense fibroelastic tissue of the more fibrotic synovia; and in the arterial wall, where it was confined to a single elastic lamina in some cases and in others showed reduplication and fragmentation. These were not related to amyloid material. It shows no disease specificity, but P component categorises the nature of the pathological reaction and is typically in biopsy specimens showing the development of chronic fibrosis. There was close codistribution of P component with elastic tissue, though this was not absolute. P component had a different distribution from C reactive protein (in synovial lining cell layer), and fibronectin, which was absent from fibrotic areas. Understanding the pathological interactions of P component may help elucidate why some synovial reactions remain inflammatory and other progress to chronic fibrosis.

Chondrocalcinosis in surgically resected joints

To investigate the association between chondrocalcinosis (CC) and osteoarthritis (OA), 338 joint specimens were examined histologically (55 knees and 84 hips surgically resected because of idiopathic OA, 106 control knees obtained postmortem, and 93 fractured hips). The risk for CC in the OA knees was sixfold that of the age- and sex-adjusted control sections. CC occurred much less frequently in the hip than in the knee; the association with OA was less clear-cut. It was not possible to resolve by statistical analysis which of the two pathological processes was the horse and which was the cart.

Systemic amyloid arthropathy associated with multiple myeloma

This is the first report of an autopsy case of systemic amyloid arthropathy associated with multiple myeloma in Japan. The patient was a 72-year-old male who had been suffering from multiple myeloma (IgA-lambda) with extensive arthropathy of the systemic joints. Autopsy examination revealed severe deposit of amyloid in the articular cavities of the systemic joints showing a feature of amyloidoma. Furthermore, numerous amyloid deposits were found in the wall of small blood vessels in the major organs. In the bone marrow, there were many atypical plasma cells and foamy cells both showing positive reaction for IgA and lambda light chain. No such atypical cells were observed in the other organs except for the bone marrow.

Synovial fluid analysis for diagnosis of amyloid arthropathy

To detect the presence of amyloid, we studied synovial fluid samples from 7 patients who had biopsy-proven amyloidosis and clinical arthropathy and from 98 patients who had other forms of arthritis. Centrifuged sediments from synovial fluids of all 7 patients with amyloid and clinical arthropathy were positive on staining with Congo red, whereas the 98 others were negative. Under polarized microscopy, the amyloid appeared as an amorphous material with strong Congo red uptake and typical apple-green birefringence. These findings indicate that analysis of synovial fluid sediments with Congo red may represent a simple, yet sensitive, test for the diagnosis of amyloid arthropathy.

Amyloid in intervertebral discs: a histopathological investigation of surgical material from 100 consecutive operations on herniated discs

Material from 100 consecutive operations on herniated discs has been investigated for amyloid. Various degrees of amyloid degeneration were found in disc tissue from 41 patients. Material from patients over 50 years old showed significantly more amyloid than that from younger patients; there was no sex difference. Eighteen patients had previously been operated on for herniated discs; seven of these (39%) had pyrophosphate deposits in their disc tissue, often in close topographical relation to amyloid. 26% of the patients had calcium phosphate deposits and 29% had slight inflammation--both without relation to amyloid. No pathogenetic correlation between amyloid degeneration and herniation of intervertebral disc tissue could be shown.

Amyloid deposits in human knee and hip joints

A systematic search for articular amyloidosis was carried out on both knees of 53 autopsy cases and on 26 femoral heads resected during surgery for hip prosthesis. Typical amyloid deposits exhibiting green apple birefringence following Congo red staining and thioflavin T fluorescence were found in 58.5% and 29% of the cases, in the knee and hip joint respectively. They occurred more frequently in articular cartilage than in the synovium, and in elderly subjects more than young ones. In the knee joint, the osteoarthritic changes and to a minor extent synovial inflammation appear to be positively correlated for the presence of intraarticular amyloid deposits. Such a correlation was not observed for the presence of calcium pyrophosphate dihydrate crystal deposits.

Age distribution of amyloid in the intervertebral discs

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