Abstract There are no definitive laboratory tests for osteoporosis, and little is known of their age-related variation. Furthermore, the knowledge of factors contributing to the occurrence of hip fracture, the most important complication of osteoporosis, during the fall is insufficient. Hip fracture is known to impair the function of elderly patients considerably at short term, but here is only limited information of the potential permanence of this impairment. The goal of treatment is to restore the patient's pre-fracture lifestyle. In this respect, intensive rehabilitation has been recommended and applied in many institutions. However, the number of critical reports on this topic is limited, and the results are heterogeneous. An assessment of the effects of age on some commonly used parameters of bone metabolism in females was performed on 238 healthy Caucasian women aged 40–86 years. It was observed that the markers of bone formation, alkaline phosphatase and osteocalcin, and the marker of bone resorption, tartrate-resistant acid phosphatase (TRACP) as well as parathyroid hormone (PTH), phosphorus and creatinine increased with age, whereas 25-hydroxyvitamin D [25(OH)D] and oestradiol decreased. All these parameters except calcium showed a significant age relation. An evaluation of the factors contributing to the occurrence of hip fracture during a fall on the hip was performed by comparing 123 hip fracture patients to 132 persons who had experienced a fall that caused a visible soft tissue injury in the hip or gluteal region without a fracture. The hip fracture patients more commonly than the fallers were women, lived in long-term institutional care, had had previous stroke with hemiparesis, had Parkinsonism, used neuroleptics, were dependent in ADL and had lower body mass indexes. According to the logistic regression model, institutional residence, low body mass index and a history of stroke with hemiplegic status differed between the fracture cases and controls. The long-term effects (mean follow-up 7 years) of trochanteric hip fracture on outcome were studied by comparing 200 consecutive patients (mean age 77 years) and age- and sex-matched controls representing the average population from the same area. Mortality increased gradually, being 4.5% above the control level at one month and 9% at six years after the fracture. 48% the surviving patients and 90% of the surviving controls were still living in their own homes or service apartments ,whereas 48% of the patients and 5% of the controls were instutionalized. The ambulatory capacity of the patients was significantly worse than controls. The patients managed their ADL activities significantly less well, required more home help and had fewer social contacts and outdoor hobbies than the controls. An assessment of the effect of intensive rehabilitation on the coping of hip fracture patients was done in a prospective randomised study on 154 patients, half of whom were treated postoperatively in a rehabilitation clinic and the other half at health care centre hospitals. Seven of the 70 survival patients of the rehabilitation group 5 of the 71 respective controls were institutionalized at one year. No difference was either observed in the walking ability or ADL functions between the groups.

La périostine est une protéine matricellulaire préférentiellement exprimée aux sites de contraintes mécaniques, notamment le périoste, et dans le stroma associé à de nombreux types de cancers. En premier lieu, nous nous sommes attachés à évaluer la pertinence de cette protéine en tant que biomarqueur du métabolisme osseux et de la réaction stromale dans les métastases osseuses. Nous avons développé le premier dosage ELISA de la périostine circulante chez la souris présentant des caractéristiques analytiques (spécificité, précision) conformes aux exigences réglementaires. Ce dosage nous a permis de préciser l’implication de la périostine dans le métabolisme osseux et les métastases osseuses de cancer du sein. Nos données in vitro et in vivo suggèrent que la périostine n’est pas un indice direct du remodelage osseux, contrairement aux marqueurs biologiques conventionnels, mais une composante de l’ossification primaire. Nous avons aussi montré dans les métastases osseuses d’origine mammaire que la périostine est surexprimée par les cellules stromales de la métastase, comme cela a pu être observé au niveau des tumeurs primaires. Enfin, nous avons confirmé par une approche bioinformatique la relation étroite entre périostine et réaction stromale dans la plupart des tumeurs chez l’Homme. La périostine et d’autres protéines conjointement exprimées pourraient donc constituer un panel de marqueurs biologiques de la progression tumorale, certains pouvant se révéler comme nouvelles cibles thérapeutiques en oncologie. / Periostin is a matricellular protein preferentially expressed at sites subjected to mechanical constraints, including the periosteum, and in the stroma associated to several tumor types. We first aimed to evaluate the relevance of periostin as a biomarker of bone metabolism or stromal reaction in bone metastases. We developed the first ELISA for serum periostin in mouse with analytical characteristics (specificity, precision) that are in accordance with regulatory standards. This ELISA allowed us to specify further the involvement of periostin in bone metabolism and breast cancer bone metastases. Our in vitro and in vivo data suggested that periostin is a component of primary ossification rather than a direct index of bone remodeling, unlike conventional bone markers. In breast cancer bone metastases, we also showed that periostin is overexpressed by stromal cells associated with bone metastasis, in agreement with its localization in the stroma of primary tumors. Finally, using bioinformatics analyses of large datasets from various tumors in human, we confirmed the close relationship between periostin and the stromal reaction. Periostin and other co-expressed proteins could therefore constitute a set of biological markers of cancer progression, and/or appear as potential therapeutic targets.

Adiponectin is a protein secreted by adipose tissue which possesses insulin-sensitivity and anti-atherosclerotic properties. In this work, we will study if high molecular weight adiponectin is a key molecule in the association between energy metabolism, thyroid axis and bone metabolism in children. To this end, we studied a population of 234 asymptomatic Caucasian children. A sample of blood was also collected to quantify HMW adiponectin, thyroid hormones, bone markers, vitamin D and sFASN. We also obtained 6 biopsies of visceral adipose tissue. The results derived from this study show a positive association of high molecular weight adiponectin with free T4 and soluble FASN and a negative association with carboxylated OC. And provide further evidence of the important role of HMW adiponectin as a biomarker of the common regulation between adipose tissue, the thyroid axis and bone metabolism in healthy children. / L'adiponectina és una proteïna secretada pel teixit adipós que té propietats insulinosensibilitzants i anti-arterioscleròtiques. L’objectiu d’aquest estudi és estudiar a l’adiponectina d’alt pes molecular com a molècula clau en la interacció entre el metabolisme energètic, l’eix tiroïdal i el metabolisme ossi. Per a tal fi, s’ha dissenyat un estudi clínic descriptiu transversal en una mostra de nens sans. A tots ells se'ls va quantificar l’adiponectina d'APM, les hormones tiroïdals, marcadors ossis, la vitamina D i FASN soluble. Addicionalment, es van obtenir 6 biòpsies de teixit adipós visceral.Els resultats derivats d’aquest estudi mostren una associació positiva de l’adiponectina d’alt pes molecular amb la T4 lliure i la FASN soluble i negativa amb la OC carboxilada. I aporten noves evidències de l'important paper de l'adiponectina d'APM com a marcador biològic de la regulació comuna entre el teixit adipòs, l’eix tiroïdal i el metabolisme ossi en edat pediàtrica.