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Calcium crystals and rapidly destructive osteoarthritis (OA)
Osteoarthritis and Cartilage Vol. 1 No. 1
15
CRYSTALS A N D OSTEOARTHRITIS Crystals and osteoarthritis: an o v e r v i e w H. RALPH SCHUMACHER JR
University of Pennsylvania, PA, U.S.A. :.i~patites and calcium pyrophosphate dihydrate (CPPD) ~ e common in osteoarthritis (OA) knee effusions but ::the frequency and pattern of calcium crystal deposition ::!i~h:::earlyOA, OA at other sites and in experimental OA, :~eed further study. Apatites are more common in joints ::~ith more destruction and are uniformly present in the :~hpidly destructive OA syndromes that may include the ::~flwaukee Shoulder'. Whether they are cause, effect, :!h~some of both in these settings remains unresolved. : C r y s t a l presence in OA does not correlate with ::Cl~ical inflammation as measured by most techniques. H ~ e v e r , crystals are frequently phagocytized and lie in
monocytes and macrophages in fluid and tissue even without other signs of inflammation. Such monocytes could contribute to cartilage damage via their enzymes and cytokines. Apatites can also be mitogens and it is suggested that they could increase fibrosis. In one study, fluids with apatites actually had less inflammation than those without. Could crystals even provide protective factors? The apatite-like crystals show a variety of different electron microscopic morphological and infrared patterns and may bind proteins differently; so clearly they are diverse. It is not yet known whether these diversities produce different biologic effects.
C h a r a c t e r i z a t i o n of ~cuboid' c a l c i u m p h o s p h a t e m i c r o c r y s t a l s in h u m a n articular cartilage S. YOUSUF ALI, COLIN SCOTCHFORD AND CHRIS BUCKLEY
Institute of Orthopaedics, University of London, Stanmore, U.K. The occurrence of 'cuboid' microcrystals of calcium phosphate in human osteoarthritic cartilage has been previously described. The aim was to study the distribution of these microcrystals in different areas of the femoral head cartilage by image analysis, to characterize their chemical composition, identify the mineral phase and to determine their mode of formation. Electron microscopy was used because these crystals are too small (about 200 nm) to be seen by radiography or light microscopy. In addition, electron probe microanalysis (EPMA) was used. The microcrystals were isolated from cartilage by collagenase digestion and centrifugal fractionation so that X-ray diffraction and electron diffraction could be applied. A new technique of soft X-ray microscopy, from a synchotron source, was used to generate a calcium map of cartilage sections.
This coincided with the morphological distribution of the microcrystals in the matrix. Histomorphometric analysis indicated that these microcrystals were highly concentrated in the superior region of the femoral head in the weight bearing area. The mean crystal size increased with age. The mean crystal area density reached 6.8~/o of the cartilage matrix in the suface zone. The EPMA results indicated a Ca/P ratio of 1.4 (with a minor peak for magnesium), which is much lower than hydroxyapatite and indictive of Mg-Whitlockite. Electron and X-ray diffraction data confirmed the microcrystals to be Mg-Whitlockite. The presence of these microcrystals in areas of cartilage stress indicate that they may be involved in various biochemical and biochemical mechanisms in addition to their association and osteoarthritis.
C a l c i u m c r y s t a l s and rapidly d e s t r u c t i v e o s t e o a r t h r i t i s (OA) T. BARDIN, B. BUCKI, J. LANSAMAN, M. LEQUESNE, A. DRYLL AND D. KUNTZ
Laboratoire d'histopathologie synoviale, Centre viggo Petersen, H6pital Lariboisiere, Paris, France Our aim was to investigate the role of calcium crystals in the rapid progression of OA. The following methods were used: (1) 100 consecutive OA synovial fluids (SF) were examined by alizarin red stain and transmission electron microscopy (TEM). Eighty-eight patients suffered from common OA and 12 from rapidly destructive OA, defined by cartilage narrowing exceeding 50% within a year. (2) Synovium and cartilage removed during prosthetic hip surgery for rapidly destructive OA (12 patients) or common OA (13 patients) were examined by TEM. Patients with radiological evidence of chondrocalcinosis were excluded from both studies.
We found that 83% o f rapid OA SF and 23% of common OA SF contained calcium (mainly apatite) crystals (P < 0.001). This difference remained significant even when age and radiological stage were taken into account. Calcium crystals (mainly apatite) were identified in synovium and/or cartilage of 80~/o and 100% of rapid and common OA joints respectively. SF calcium crystals may be associated with a rapid course of OA, but at the late stage when prosthetic joint surgery, is required calcium deposits no longer appear specific for rapidly destructive OA.
15
CRYSTALS A N D OSTEOARTHRITIS Crystals and osteoarthritis: an o v e r v i e w H. RALPH SCHUMACHER JR
University of Pennsylvania, PA, U.S.A. :.i~patites and calcium pyrophosphate dihydrate (CPPD) ~ e common in osteoarthritis (OA) knee effusions but ::the frequency and pattern of calcium crystal deposition ::!i~h:::earlyOA, OA at other sites and in experimental OA, :~eed further study. Apatites are more common in joints ::~ith more destruction and are uniformly present in the :~hpidly destructive OA syndromes that may include the ::~flwaukee Shoulder'. Whether they are cause, effect, :!h~some of both in these settings remains unresolved. : C r y s t a l presence in OA does not correlate with ::Cl~ical inflammation as measured by most techniques. H ~ e v e r , crystals are frequently phagocytized and lie in
monocytes and macrophages in fluid and tissue even without other signs of inflammation. Such monocytes could contribute to cartilage damage via their enzymes and cytokines. Apatites can also be mitogens and it is suggested that they could increase fibrosis. In one study, fluids with apatites actually had less inflammation than those without. Could crystals even provide protective factors? The apatite-like crystals show a variety of different electron microscopic morphological and infrared patterns and may bind proteins differently; so clearly they are diverse. It is not yet known whether these diversities produce different biologic effects.
C h a r a c t e r i z a t i o n of ~cuboid' c a l c i u m p h o s p h a t e m i c r o c r y s t a l s in h u m a n articular cartilage S. YOUSUF ALI, COLIN SCOTCHFORD AND CHRIS BUCKLEY
Institute of Orthopaedics, University of London, Stanmore, U.K. The occurrence of 'cuboid' microcrystals of calcium phosphate in human osteoarthritic cartilage has been previously described. The aim was to study the distribution of these microcrystals in different areas of the femoral head cartilage by image analysis, to characterize their chemical composition, identify the mineral phase and to determine their mode of formation. Electron microscopy was used because these crystals are too small (about 200 nm) to be seen by radiography or light microscopy. In addition, electron probe microanalysis (EPMA) was used. The microcrystals were isolated from cartilage by collagenase digestion and centrifugal fractionation so that X-ray diffraction and electron diffraction could be applied. A new technique of soft X-ray microscopy, from a synchotron source, was used to generate a calcium map of cartilage sections.
This coincided with the morphological distribution of the microcrystals in the matrix. Histomorphometric analysis indicated that these microcrystals were highly concentrated in the superior region of the femoral head in the weight bearing area. The mean crystal size increased with age. The mean crystal area density reached 6.8~/o of the cartilage matrix in the suface zone. The EPMA results indicated a Ca/P ratio of 1.4 (with a minor peak for magnesium), which is much lower than hydroxyapatite and indictive of Mg-Whitlockite. Electron and X-ray diffraction data confirmed the microcrystals to be Mg-Whitlockite. The presence of these microcrystals in areas of cartilage stress indicate that they may be involved in various biochemical and biochemical mechanisms in addition to their association and osteoarthritis.
C a l c i u m c r y s t a l s and rapidly d e s t r u c t i v e o s t e o a r t h r i t i s (OA) T. BARDIN, B. BUCKI, J. LANSAMAN, M. LEQUESNE, A. DRYLL AND D. KUNTZ
Laboratoire d'histopathologie synoviale, Centre viggo Petersen, H6pital Lariboisiere, Paris, France Our aim was to investigate the role of calcium crystals in the rapid progression of OA. The following methods were used: (1) 100 consecutive OA synovial fluids (SF) were examined by alizarin red stain and transmission electron microscopy (TEM). Eighty-eight patients suffered from common OA and 12 from rapidly destructive OA, defined by cartilage narrowing exceeding 50% within a year. (2) Synovium and cartilage removed during prosthetic hip surgery for rapidly destructive OA (12 patients) or common OA (13 patients) were examined by TEM. Patients with radiological evidence of chondrocalcinosis were excluded from both studies.
We found that 83% o f rapid OA SF and 23% of common OA SF contained calcium (mainly apatite) crystals (P < 0.001). This difference remained significant even when age and radiological stage were taken into account. Calcium crystals (mainly apatite) were identified in synovium and/or cartilage of 80~/o and 100% of rapid and common OA joints respectively. SF calcium crystals may be associated with a rapid course of OA, but at the late stage when prosthetic joint surgery, is required calcium deposits no longer appear specific for rapidly destructive OA.