Publications by authors named "Norbert Laroche"

Menopause exacerbates osteoporosis and increases the risk of atherosclerotic plaque rupture, leading to cardiovascular mortality. Osteoporotic women are increasingly treated with teriparatide (TPTD, 1-34 parathyroid hormone), one of the few treatments that stimulate bone formation. Despite the fact that atherosclerotic plaque calcification is a hallmark of plaque development, the impact of TPTD administration on plaque calcification remain unclear.

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The skin, the outermost organ of the human body, is vital for sensing and responding to stimuli through mechanotransduction. It is constantly exposed to mechanical stress. Consequently, various mechanical therapies, including compression, massage, and microneedling, have become routine practices for skin healing and regeneration.

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Osteopontin (OPN) and Bone Sialoprotein (BSP), abundantly expressed by osteoblasts and osteoclasts, appear to have important, partly overlapping functions in bone. In gene-knockout (KO, -/-) models of either protein and their double (D)KO in the same CD1/129 genetic background, we analyzed the morphology, matrix characteristics, and biomechanical properties of femur bone in 2 and 4 month old, male and female mice. OPN mice display inconsistent, perhaps localized hypermineralization, while the BSP are hypomineralized throughout ages and sexes, and the low mineralization of young DKO mice recovers with age.

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Aging is associated with detrimental bone loss leading to fragility fractures in both men and women. Notably, a majority of bone loss with aging is cortical, as well as a large number of fractures are non-vertebral and at the non-hip sites. Nacre is a product of mollusks composed of calcium carbonate embedded in organic components.

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Purpose: Analysis of cochlear structures and postoperative temporal bone (TB) imaging are gaining importance in the evaluation of cochlear implantation (CI°). Our aims were to explore the microarchitecture of human cochlea using micro-computed tomography (μCT), analyze electrode's placement inside cochlea after CI°, and compare pre-/post-implantation μCT scans with cone-beam CT (CBCT) scans of same TBs.

Methods: Cadaveric TBs were scanned using μCT and CBCT then underwent CI° using straight electrodes.

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Objectives: The purpose of this preclinical study was to evaluate the safety, the local tissue effects and bone healing performance (osteoconduction, osseointegration) of nacre powder in a sheep intraosseous implantation model. This represents the first preclinical study to assess nacre safety and efficacy in supporting new bone formation in accordance with the ISO 10993 standard for biomedical devices.

Methods: The local tissue effects and the material performance were evaluated 8 weeks after implantation by qualitative macroscopic observation and qualitative as well as semiquantitative microscopic analyses of the bone sites.

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Nacre has emerged as a beneficial natural product for bone cells and tissues, but its effect was only studied by gavage in the ovariectomized mouse model. We sought to assess the antiosteoporotic effect of nacre through a nutritional supplementation in the ovariectomized rat model. Sixteen-week-old female Wistar rats were either Sham-operated or bilateral ovariectomized (OVX) and then fed with standard diet (Sham and OVX groups) or standard diet supplemented with either 0.

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Sjögren's syndrome (SjS) is a frequent systemic autoimmune disease responsible for a major decrease in patients' quality of life, potentially leading to life-threatening conditions while facing an unmet therapeutic need. Hence, we assessed the immunogenicity, efficacy, and tolerance of IFN-Kinoid (IFN-K), an anti-IFNα vaccination strategy, in a well-known mouse model of systemic autoimmunity with SjS-like features: MRL/MpJ-Faslpr/lpr (MRL/lpr) mice. Two cohorts (with ISA51 or SWE01 as adjuvants) of 26 female MRL/lpr were divided in parallel groups, "controls" (not treated, PBS and Keyhole Limpet Hemocyanin [KLH] groups) or "IFN-K" and followed up for 122 days.

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Insights into the effects of osteoarthritis (OA) and physical interventions on the musculoskeletal system are limited. Our goal was to analyze musculoskeletal changes in OA mice and test the efficacy of 8-week exposure to hypergravity, as a replacement of physical activity. 16-week-old male (C57BL/6J) mice allocated to sham control and OA groups not centrifuged (Ctrl 1g and OA 1g, respectively) or centrifuged at 2g acceleration (Ctrl 2g and OA 2g).

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Spaceflight-induced bone losses have been reliably reproduced in Hind-Limb-Unloading (HLU) rodent models. However, a considerable knowledge gap exists regarding the effects of low-dose radiation and microgravity together. Ten-week-old male C57BL/6J mice, randomly allocated to Control (CONT), Hind-Limb Unloading (HLU), and Hind-Limb Unloading plus Irradiation (HLUIR), were acclimatized at 28 °C, close to thermoneutral temperature, for 28 days prior to the 14-day HLU protocol.

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In this paper, the objective is to assess the histomechanical effects of collagen proteolysis in arteries under loading conditions reproducing in vivo environment. Thirteen segments of common porcine carotid arteries (8 proximal and 5 distal) were immersed in a bath of bacterial collagenase and tested with a pulsatile tension/inflation machine. Diameter, pressure and axial load were monitored throughout the tests and used to derive the stress-stretch curves and to determine the secant circumferential stiffness.

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Mammalian phospholipase D (PLD) mostly hydrolyzes phosphatidylcholine producing phosphatidic acid. PLD activity was previously detected in different osteoblastic cell models, and was increased by several growth factors involved in bone homeostasis. To confirm possible actions of PLD isoforms during mineralization process, we analyzed their effects in osteoblastic cell models and during bone formation.

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Periarticular bone loss in rheumatoid arthritis (RA) is considered to be mainly related to synovial inflammation. However, strong bone loss has also described at the time of arthritis onset. Recently, a paradoxical exacerbation of joint damage was described when blocking sclerostin in various arthritis models.

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Disorders in the wall microstructure underlie all forms of vascular disease, such as the aortic aneurysm, the rupture of which is necessarily triggered at the microscopic level. In this context, we developed an original experimental approach, coupling a bulge inflation test to multiphoton confocal microscopy, for visualizing the 3D micro-structure of porcine, human non-aneurysmal and aneurysmal aortic adventitial collagen under increasing pressurization. The experiment complexity on such tissues led to deeply address the acquisition major hurdles.

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Little is known about middle and inner ear development during the second and third parts of human fetal life. Using ultra-high resolution Microcomputed Tomography coupled with bone histology, we performed the first quantitative middle and inner ear ossification/mineralization evaluation of fetuses between 17 and 39 weeks of gestational age. We show distinct ossification paces between ossicles, with a belated development of the stapes.

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The purpose of the study was to assess the rate of protein synthesis (PS) and elucidate signalling pathways regulating PS in mouse soleus (Sol) and tibialis anterior (TA) muscles following chronic hypergravity (30-day centrifugation at 2G). The content of the key signalling proteins of the various anabolic signalling pathways was determined by Western-blotting. The rate of PS was assessed using in-vivo SUnSET technique.

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The weightless environment during spaceflight induces site-specific bone loss. The 30-day Bion-M1 mission offered a unique opportunity to characterize the skeletal changes after spaceflight and an 8-day recovery period in mature male C57/BL6 mice. In the femur metaphysis, spaceflight decreased the trabecular bone volume (-64% vs.

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Syndesmophyte occurrence and axial bone loss were investigated in the heterozygous Tg187 tumor necrosis factor (TNF) transgenic mouse model (Tg-huTNF) of arthritis. Female and male Tg-huTNF mice were compared to wild-type mice (WT) at 2, 4, 6, 8, and 10 weeks. Syndesmophytes, intervertebral disc space, osteoclasts, osteoid surface, and vertebra microarchitecture were assessed by histomorphometry and microcomputed tomography.

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Dual-energy X-ray absorptiometry (DXA) is currently the most widely used technique for measuring areal bone mineral density (BMD). However, several studies have shown inaccuracy, with either overestimation or underestimation of DXA BMD measurements in the case of overweight or obese individuals. We have designed an overweight rat model based on junk food to compare the effect of obesity on in vivo and ex vivo BMD and bone mineral content measurements.

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Whole body vibration (WBV) is a promising tool for counteracting bone loss. Most WBV studies on animals have been performed at acceleration <1g and frequency between 30 and 90Hz. Such WBV conditions trigger bone growth in osteopenia models, but not in healthy animals.

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Bone Sialoprotein (BSP) is a member of the "Small Integrin-Binding Ligand N-linked Glycoproteins" (SIBLING) extracellular matrix protein family of mineralized tissues. BSP has been less studied than other SIBLING proteins such as Osteopontin (OPN), which is coexpressed with it in several skeletal cell types. Here we review the contribution of genetically engineered mice (BSP gene knockout and overexpression) to the understanding of the role of BSP in the bone organ.

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One of the most important but least studied environmental factors playing a major role in bone physiology is gravity. While the knowledge of deleterious effects of microgravity on the skeleton is expanding, little is known about hypergravity and its osteogenic potential. Centrifugation was used to assess effects of 21-day continuous 2- or 3-g acceleration on femur and L2-vertebra of 7-wk-old male C57BL/6 mice.

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Metabolic and bone effects were investigated in growing (G, n = 45) and mature (M, n = 45) rats fed a high-fat/high-sucrose diet (HFS) isocaloric to the chow diet of controls (C, n = 30 per group). At week 19, a subset of 15 rats in each group (HFS or C, at both ages) was analyzed. Then one-half of the remaining 30 HFS rats in each groups continued HFS and one-half were shifted to C until week 27.

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Bone cells exposed to real microgravity display alterations of their cytoskeleton and focal adhesions, two major mechanosensitive structures. These structures are controlled by small GTPases of the Ras homology (Rho) family. We investigated the effects of RhoA, Rac1, and Cdc42 modulation of osteoblastic cells under microgravity conditions.

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