  Osteoarthritis (OA) is a pathology that ultimately causes joint destruction.
The cartilage is one of the principal affected tissues. Alterations in the
lipid mediators and an imbalance in the metabolism of cells that form the
cartilage (chondrocytes) have been described as contributors to the OA
development. In this study, we have studied the distribution of lipids and
chemical elements in healthy and OA human cartilage. Time of flight-secondary
ion mass spectrometry (TOF-SIMS) allows us to study the spatial distribution of
molecules at a high resolution on a tissue section. TOF-SIMS revealed a
specific peak profile that distinguishes healthy from OA cartilages. The
spatial distribution of cholesterol-related peaks exhibited a remarkable
difference between healthy and OA cartilages. A distinctive colocalization of
cholesterol and other lipids in the superficial area of the cartilage was
found. A higher intensity of oleic acid and other fatty acids in the OA
cartilages exhibited a similar localization. On the other hand, CN(-) was
observed with a higher intensity in the healthy samples. Finally, we observed
an accumulation of calcium and phosphate ions exclusively in areas surrounding
the chondrocyte in OA tissues. To our knowledge, this is the first time that
TOF-SIMS revealed combined changes in the molecular distribution in the OA
human cartilage.
