Lipid Composition of the Tissues of Human Knee Joints

Rabinowitz, Joseph L.; Gregg, John R.; Nixon, James E.

doi:10.1097/00003086-198411000-00052

Cited by 34 publications

(20 citation statements)

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“…SF is composed of HA ranging from 2,000 kd to 10,000 kd (30,44), PRG4 proteins ranging from ϳ14 kd to ϳ345 kd (4,45), and SAPL of different types with DPPC being a major form (33). HA has been shown to lubricate at a cartilage-cartilage interface on a joint scale equally well at 1,030 kd and 1,930 kd (14), and certain other properties of HA do not depend on molecular weight either (in the range of 500-6,000 kd) (46).…”

Section: Discussionmentioning

confidence: 99%

“…The maintenance of the boundary-lubricating ability of SF, at the cartilagecartilage interface tested here, even at a 3-fold dilution, suggests that the lubricant molecules in SF are normally present in excess. However, the rapid decline in boundarylubricating ability with a further decrease in constituent concentration suggests that such an alteration, which can occur in the settings of both injury and disease (28)(29)(30)32,33,53), can impair lubricating function. The combination of the SF constituents HA, PRG4, and SAPL at physiologic concentrations approaching, but not fully replicating, the boundary-lubricating ability of SF suggests that additional lubricant molecules and/or complexes remain to be identified.…”

Section: Discussionmentioning

confidence: 99%

“…Conversely, using a rabbit knee injury model, the concentration of PRG4 in SF decreased from 280 g/ml to 20-100 g/ml 3 weeks after injury (32). The majority of the lipids in human SF are phospholipids, the concentration of which ranges from ϳ0.1 mg/ml to ϳ0.2 mg/ml in normal individuals, increases in osteoarthritis to ϳ0.2-0.3 mg/ml (28), and can decrease following traumatic injury to ϳ0.02-0.08 mg/ml (33). While most phospholipids are surface active, dipalmitoyl-phosphatidylcholine (DPPC) is particularly so and is the most abundant form present in SF at ϳ45% (6,34).…”

mentioning

confidence: 96%

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Boundary lubrication of articular cartilage: Role of synovial fluid constituents

Schmidt

Gastelum

Nguyen

et al. 2007

Arthritis & Rheumatism

471

510

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Objective. To determine whether the synovial fluid (SF) constituents hyaluronan (HA), proteoglycan 4 (PRG4), and surface-active phospholipids (SAPL) contribute to boundary lubrication, either independently or additively, at an articular cartilage-cartilage interface.Methods. Cartilage boundary lubrication tests were performed with fresh bovine osteochondral samples. Tests were performed using graded concentrations of SF, HA, and PRG4 alone, a physiologic concentration of SAPL, and various combinations of HA, PRG4, and SAPL at physiologic concentrations. Static ( static, Neq ) and kinetic (< kinetic, Neq >) friction coefficients were calculated.Results. Normal SF functioned as an effective boundary lubricant both at a concentration of 100% (< kinetic, Neq > ‫؍‬ 0.025) and at a 3-fold dilution (< kinetic, Neq > ‫؍‬ 0.029). Both HA and PRG4 contributed independently to a low in a dose-dependent manner. Values of < kinetic, Neq > decreased from ϳ0.24 in phosphate buffered saline to 0.12 in 3,300 g/ml HA and 0.11 in 450 g/ml PRG4. HA and PRG4 in combination lowered further at the high concentrations, attaining a < kinetic, Neq > value of 0.066. SAPL at 200 g/ml did not significantly lower , either independently or in combination with HA and PRG4. Conclusion. The results described here indicate that SF constituents contribute, individually and in combination, both at physiologic and pathophysiologic concentrations, to the boundary lubrication of apposing articular cartilage surfaces. These results provide insight into the nature of the boundary lubrication of articular cartilage by SF and its constituents. They therefore provide insight regarding both the homeostatic maintenance of healthy joints and pathogenic processes in arthritic disease.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 96%

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Boundary lubrication of articular cartilage: Role of synovial fluid constituents

Schmidt

Gastelum

Nguyen

et al. 2007

Arthritis & Rheumatism

471

510

View full text Add to dashboard Cite

show abstract

“…9 Finally, findings also have shown trauma to be a rare cause of chylous effusion. 10 Cases of posttraumatic chylous effusion are separated into those that occur in the presence of fracture and the absence of fracture. In the setting of subchondral fracture, the greatest potential source of lipid as a cause of chylous effusion is the marrow cavity.…”

Section: Discussionmentioning

confidence: 99%

Chylous Knee Effusion: Is It Septic Arthritis? A Case Report and Review of Literature

Soojian

Tejwani

2004

The Journal of Trauma: Injury, Infection, and Critical Care

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“…Detailed characterization of the synovial fluid lipids in this patient demonstrated markedly elevated levels of neutral fats and very little phospholipid. Rabinowitz et al have shown that human bone marrow (femur), the intraarticular fat pad of the knee, and the synovium are composed of 96%, 98%, and 91% neutral fats, respectively, with triglycerides composing the great majority of these fats (20). Phospholipids make up <7% of these structures but are present in increased amounts (30-40%) in articular cartilage, synovial fluid, and ligaments.…”

mentioning

confidence: 99%