The Phospholipids Activity in Normal and Osteoarthritic Cartilage

Research Article

Gerontol Geriatr Res. 2020; 6(1): 1042.

The Phospholipids Activity in Normal and Osteoarthritic Cartilage

Pawlak Z*

Tribochemistry Consulting, University of Economy, Poland

*Corresponding author: Zenon Pawlok, Tribochemistry Consulting, University of Economy, Biotribology Lab, Garbary 2, 85-229, Bydgoszcz, Poland

Received: April 06, 2020; Accepted: May 01, 2020; Published: May 08, 2020


The purpose of this paper is to study Phospholipids (PLs) in osteoporotic samples (OA) changes in Synovial Fluid (SF). The (PLs) in (SF) were measured for normal samples, with early and late stages of (OA). During osteoarthritis, enzymatically activated β2-Glycoprotein I is transformed into antibody conformation. Cartilage degradation of PL bilayers by antibodies (β2- Glycoprotein I) is considered Anti Phospholipid Syndrome (APS). Deactivated PL molecule has no ability to form bilayers and liposomes. The phospholipid content in Synovial Fluid (SF) in osteoporotic samples is significantly higher (2-3 times) above the normal concentration of PL and has a poor boundarylubricating ability.

Kewords: Cartilage; Deactivated phospholipid; Osteoarthritis; β2- Glycoprotein I; Anti Phospholipid Syndrome (APS)


A general model of cartilage boundary lubrication has been proposed and is based on a layer of biomolecules that covers the surfaces of articular cartilage and acts as a lubricant [1,2]. Lubricating molecules of Synovial Fluid (SF), such as hyaluronan (A-) [1], lubricin [3], and surface-active phospholipids [4], adsorb to the surface of articular cartilage and support boundary lubrication [2]. However, according to Hills, PLs is the most important SF component in maintaining efficient joint lubrication [5]. In PL bilayer model the macromolecules (hyaluronan and lubricine) of SF play supportive role. The phospholipid bilayers on the surface of articular cartilage are a main lubricant and during joint inflammation and OA are destroyed. Unexpected elimination of self-organized of PLs in SF is an indication of joint deterioration. A joint disease named Osteoarthritis (OA) or degenerative arthritis is caused by the damage to the cartilage surface tissue in the joint and causes pain and stiffness. Rheumatoid Arthritis (RA) is an autoimmune disease with signs and symptoms that include joint swelling, pain, prolonged morning joint stiffness, fatigue, muscle atrophy, and joint erosions [5]. Osteoarthritis (OA) is a common disease, where the mechanical integrity of articular cartilage is weakened. Two steps occur on surface destruction (a) the first is depletion of phospholipid bilayers and (b) second is proteoglycan loss of damaged cartilage matrix by injurious loading. From our experiment we can predict proteoglycan loss of injured cartilage by decreasing the Fixed Charge Density (FCD) concentration. Electrostatic lubrication of osteoarthritic cartilage is operated by decreasing the Fixed Charge Density (FCD) concentration on surface. This is consistent with experimental findings in the literature. Level of PLs in SF shows a great potential for predicting the progression of (OA) via analytical evaluation content of PLs.

Our objective was to evaluate the changes of phospholipid in synovial fluid of cartilages on early (eOA), and late (lOA) stage of osteoarthritic and with Rheumatoid Arthritis (RA) disease. In this work PLs concentration were measured on healthy and pathological joints surfaces.

In this study, we tried to identify degradation bilayers of PLs (surface of AC) as well as deactivation of phospholipid molecules in the Synovial Fluid (SF) from samples either with active Rheumatoid Arthritis (RA) or with early or late stages of Osteoarthritis (OA).

Materials and Methods

Mass spectrometr of phospholipids: The phospholipid species were quantified by ESI-MS/MS on Micromass [6,7]. The research was carried out using synovial fluid derived from undamaged controls and patients with early and late osteoarthritis and rheumatoid arthritis. The authors classified 130 species of lipids. After comparing control synovial fluids, SF of patient with early and late OA had higher levels of most PLs species. Most of the PL data for this paper was taken from Kosinska et al [7].


Hyaluronan, lubricin, and phospholipids contribute to cartilage boundary lubrication that is provided by SF. PL is the most important SF component in maintaining efficient joint lubrication. Phospholipids are believed to cover the surface of articular cartilage, where they form self-organized bilayers of phospholipids, (Figure1A) [4,5] and provide supportive function of hyaluronan and lubricin aqueous hydration in healthy cartilage boundary lubrication. The concentration level of phospholipids increased in SF with early- and late stage OA, and patients with active RA is given in [5] (Figure 1B). Compared to synovial fluid from controls, SF from patients with early (eOA) and those with late (lOA) had higher levels of most PLs species (2 to 3 times) above the normal range (Figure 1B).