Effect of particle size on hydroxyapatite crystal-induced tumor necrosis factor alpha secretion by macrophages.

Macrophages may promote a vicious cycle of inflammation and calcification in the vessel wall by ingesting neointimal calcific deposits (predominantly hydroxyapatite) and secreting tumor necrosis factor (TNF)alpha, itself a vascular calcifying agent. Here we have investigated whether particle size affects the proinflammatory potential of hydroxyapatite crystals in vitro and whether the nuclear factor (NF)-kappaB pathway plays a role in the macrophage TNFalpha response. The particle size and nano-topography of nine different crystal preparations was analyzed by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and gas sorbtion analysis.

Fibulins and cancer: friend or foe?

The fibulins are a family of secreted glycoproteins, which are characterised by repeated epidermal-growth-factor-like domains and a unique C-terminal structure. Six distinct fibulin genes, encoding at least nine protein products generated by alternative splicing, have been identified. Considerable evidence is available pointing towards a structural role for fibulins within the extracellular matrix.

Basic calcium phosphate crystals as a unique therapeutic target in osteoarthritis.

Osteoarthritis (OA) is the most common form of arthritis that occurs in humans. Despite its prevalence, the pathogenesis of OA is not fully understood. Intraarticular basic calcium phosphate (BCP) (an inclusive term for partially carbonate-substituted hydroxyapatite, octacalcium phosphate and tricalcium phosphate) crystals are implicated in OA and are associated with severe degenerative arthritis characterized by marked synovial hyperplasia, aggravated joint degeneration and large joint effusions.

Basic calcium phosphate crystal-induced prostaglandin E2 production in human fibroblasts: role of cyclooxygenase 1, cyclooxygenase 2, and interleukin-1beta.

Objective: To elucidate the mechanism of basic calcium phosphate (BCP) crystal-induced prostaglandin E(2) (PGE(2)) production in human foreskin fibroblasts (HFFs), to identify the signaling pathway involved in the induction of cyclooxygenase 2 (COX-2) messenger RNA (mRNA) by BCP crystals, to examine the effect of BCP crystals on interleukin-1beta (IL-1beta) mRNA expression, and to investigate the potential of phosphocitrate to abrogate the BCP crystal-induced effects.

Methods: PGE(2) levels were quantified using a commercial enzyme immunoassay kit. COX-2 and COX-1 transcript levels were quantified using real-time reverse transcriptase-polymerase chain reaction (RT-PCR).