Rhesus macaques as an experimental model for degenerative arthritis

To understand the pathogenesis of degenerative arthritis, an experimental model of the disease in which systemic factors can be investigated is required. This study reviews the evidence that the spontaneous degenerative arthritis in free ranging rhesus macaques at the Caribbean Primate Research Center meets the criteria for such a model. Two forms of degenerative arthritis in rhesus macaques have been identified: osteoarthritis and calcium pyrophosphate dihydrate crystal deposition disease. These diseases resemble spontaneous human arthritis with respect to age, sex, joint histology and cartilage composition. The availability of large numbers of affected primates as well as the availability of age/sex matched controls free of disease are additional factors that make spontaneous degenerative arthritis in rhesus macaques a suitable experimental model for the study of the human disease.

Calcium pyrophosphate dihydrate deposition in lumbar disc fibrocartilage

Calcium pyrophosphate dihydrate deposits were found in the lumbar disc fibrocartilage in 4 patients undergoing surgery for spinal cord or nerve root compression. All of the patients had prior surgery at the same lumbar area. None of the patients had the articular or roentgenographic manifestations of calcium pyrophosphate deposition disease (pseudogout). Andres and Trainer have recently reported 7 similar patients. Calcium pyrophosphate dihydrate deposition in axial skeleton fibrocartilage may be a common finding in patients undergoing repeat spinal surgery.

Cartilage matrix in hereditary pyrophosphate arthropathy

Morphological and biochemical studies of articular cartilage were performed in 6 members of 3 families with hereditary pyrophosphate arthropathy. Evidence of metabolic disturbance of cartilage matrix was obtained from light and electron microscopic findings and by the content and composition of glycosaminoglycans.

Calcium pyrophosphate dihydrate deposition disease and familial hypomagnesemia

A 40-year-old woman presented with calcium pyrophosphate synovitis and chondrocalcinosis. She was subsequently found to have hypomagnesemia, as did her 22-year-old son. Metabolic studies demonstrated normal gastrointestinal absorption of magnesium, and impaired renal conservation of magnesium without other evidence of renal tubular dysfunction. It seems likely that a genetically determined abnormality of magnesium metabolism was responsible for the occurrence of chondrocalcinosis in this patient.

Calcium pyrophosphate crystal formation in model hydrogels. II. Hyaline articular cartilage as a gel

We studied calcium pyrophosphate crystal formation in an in vitro cartilage system. Two parallel troughs were excavated in tibial plateau articular cartilage obtained postmortem. One well was filled with solid sodium pyrophosphate, the other with calcium chloride. After incubation for 24 h at either 10 degrees C or 37 degrees C the precipitate band between the troughs was analyzed for the size and nature of crystals present. In subsequent experiments, the cartilage was pretreated by laceration, contusion, trypsin or hyaluronidase denaturation. We found that cartilage denaturation resulted in formation of larger crystals but that the crystal product in all experiments was identical, alpha CaNa2P2O7.4H2O a nonphysiologic crystal.