BackgroundFracture healing is orchestrated by a specific set of events that culminates in the repair of bone and reachievement of its biomechanical properties. The aim of our work was to study the sequence of gene expression events involved in inflammation and bone remodeling occurring in the early phases of callus formation in osteoporotic patients.Methodology/Principal FindingsFifty-six patients submitted to hip replacement surgery after a low-energy hip fracture were enrolled in this study. The patients were grouped according to the time interval between fracture and surgery: bone collected within 3 days after fracture (n = 13); between the 4th and 7th day (n = 33); and after one week from the fracture (n = 10). Inflammation- and bone metabolism-related genes were assessed at the fracture site. The expression of pro-inflammatory cytokines was increased in the first days after fracture. The genes responsible for bone formation and resorption were upregulated one week after fracture. The increase in RANKL expression occurred just before that, between the 4th–7th days after fracture. Sclerostin expression diminished during the first days after fracture.ConclusionsThe expression of inflammation-related genes, especially IL-6, is highest at the very first days after fracture but from day 4 onwards there is a shift towards bone remodeling genes, suggesting that the inflammatory phase triggers bone healing. We propose that an initial inflammatory stimulus and a decrease in sclerostin-related effects are the key components in fracture healing. In osteoporotic patients, cellular machinery seems to adequately react to the inflammatory stimulus, therefore local promotion of these events might constitute a promising medical intervention to accelerate fracture healing.

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Interleukin-6 (IL-6) is a multifunctional cytokine with an important pathophysiological role in systemic lupus erythematosus (SLE). The polymorphism of the IL-6 gene promoter at position -174, which appears to influence the production of this cytokine, has been associated with susceptibility to some rheumatic diseases. The aim of this study is to investigate whether the IL-6 -174 G/C polymorphism associates with lupus susceptibility or affects disease characteristics in Portuguese patients with SLE. The association between -174 G/C and lupus diagnosis was studied in 115 adult SLE patients (95.7% females) and 152 healthy controls (94.7% females), all Caucasians. There were no significant differences in genotype or allele frequency between patients and controls. The -174 C/C genotype was independently associated with renal disease and the C allele with the presence of irreversible damage. The IL-6 gene promoter polymorphism at position -174 does not contribute to SLE susceptibility in Portuguese Caucasian patients but may predispose to specific manifestations of the disease.