An ultrastructural and light microscopic study of the synovium in ochronotic arthropathy

Gaines, Joseph J.; Tom, Gary D.; Khankhanian, Nayereh

doi:10.1016/s0046-8177(87)80385-4

Cited by 16 publications

(9 citation statements)

References 6 publications

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“…Their cytoplasm was full of phagocytosed pigment granules. These resembled those previously described in synovial cells and in macrophages [7,12]. A small number of granules were also found in osteoclasts.…”

Section: Discussionsupporting

confidence: 89%

A morphological study of bone and articular cartilage in ochronosis

Franco

Coari

Bonucci³

2000

Virchows Archiv

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An ochronotic femoral head has been studied morphologically under the light and the electron microscope. Its articular cartilage showed the alterations already reported in the literature, mainly consisting of erosions of the surface, pigment accumulation in chondrocytes and intercellular matrix, chondrocyte degeneration, the formation of pigmented, calcified and uncalcified microshards, and the presence of granulation tissue with macrophagic cells. The changes in bone were less severe than those in cartilage. Pigment was present in the calcified matrix. This did not seem to disturb the organization of the bone tissue, although it was diffusely osteoporotic, perhaps because of limb disuse. The preservation of calcified matrix might depend on the fact that its collagen fibrils are encrusted by mineral substance, which avoids the dangerous effects that the deposition of ochronotic pigment induces in the fibrils of soft connective tissues. On the other hand, the newly formed osteoid matrix remains uncalcified for too short a time to be modified by the pigment. Diffuse or granular pigmentation was found in a few osteocytes, while several of them were condensed or reduced to cellular fragments. Bone resorption often occurred near these osteocytes. However, this did not seem to alter the degree of bone remodelling, possibly because of the relatively low numbers of degenerated or dead osteocytes. Pigment was also contained in the cytoplasmic vacuoles of otherwise active osteoclasts, whereas it was not found in osteoblasts. On the whole, ochronosis in bone seems to induce the same changes as in other connective tissues. However, their severity appears to be limited by calcification, which prevents modifications in collagen fibrils, and by bone remodelling, which to some extent eliminates the oldest, pigment-richest parts of the tissue.

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Section: Discussionsupporting

confidence: 89%

A morphological study of bone and articular cartilage in ochronosis

Franco

Coari

Bonucci³

2000

Virchows Archiv

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“…The synovial tissue may also show chondroid metaplasia 3 . Electron microscopy of synovial tissues shows pigment surrounding individual collagen fibres interpreted as microshards of ochronotic cartilage 22 . Pigmentation of the sacro‐iliac joints has not been described in previous studies.…”

Section: Introductionmentioning

confidence: 86%

Alkaptonuria – a review of surgical and autopsy pathology

2008

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Alkaptonuria is a rare, inherited defect of homogentisic acid 1,2-dioxygenase that leads to the widespread deposition of polymeric homogentisic acid, and clinical symptoms from degeneration of joints and the aortic valve. Pathological descriptions are few and mainly those of late-stage changes related to joint or valve failure. In this review, the macroscopic and histopathological changes in the tissues in alkaptonuria are illustrated by the detailed autopsy study of a 74-year-old female who died from disseminated ovarian carcinoma. The pathology is discussed in the context of the literature and in relation to potential pathogenic mechanisms of tissue damage. This review highlights the heterogeneity of some of the manifestations. In symptomatic patients, degenerative changes in synovial and intervertebral joints are usually well advanced, while early changes include diffuse cartilage pigmentation and chondrocyte necrosis. The initial stage of pigment deposition in the cardiovascular system may be influenced by intravascular pressure and flow disturbances, whereas more intense pigmentation affects fibrolipid components of atheromatous plaques. Pigmentation of the aortic and mitral valve cusps and valve rings is a result of intracellular and extracellular pigment deposition and is associated with calcification and clinically significant aortic stenosis.

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“…It is currently believed that the OP process is not fully reversible, although there are indications of some reversal of pigment; the mechanism of such reversal is currently unknown . It is not known if the OP process is dynamic, that is, formation and removal co‐existing, although macrophages with pigment has been described in case reports …”

Section: Formation Of Ochronotic Pigmentmentioning

confidence: 99%

Ochronotic pigmentation is caused by homogentisic acid and is the key event in alkaptonuria leading to the destructive consequences of the disease—A review

Ranganath

Norman

Gallagher

2019

J of Inher Metab Disea

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Ochronosis is the process in alkaptonuria (AKU) that causes all the debilitating morbidity. The process involves selective deposition of homogentisic acid (HGA)‐derived pigment in tissues altering the properties of these tissues, leading to their failure. Some tissues like cartilage are more easily affected by ochronosis while others such as the liver and brain are unaffected for reasons that are still not understood. In vitro and mouse models of ochronosis have confirmed the dose relationships between HGA and ochronosis and also their modulation by p‐hydroxyphenylpyruvate dioxygenase inhibition. Ochronosis cannot be fully reversed and is a key factor in influencing treatment decisions. Earlier detection of ochronosis preferably by noninvasive means is desirable. A cause‐effect relationship between HGA and ochronosis is discussed. The similarity in AKU and familial hypercholesterolaemia is explored and lessons learnt. More research is needed to more fully understand the crucial nature of ochronosis.

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An ultrastructural and light microscopic study of the synovium in ochronotic arthropathy

Cited by 16 publications

References 6 publications

A morphological study of bone and articular cartilage in ochronosis

A morphological study of bone and articular cartilage in ochronosis

Alkaptonuria – a review of surgical and autopsy pathology

Ochronotic pigmentation is caused by homogentisic acid and is the key event in alkaptonuria leading to the destructive consequences of the disease—A review

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