CCR3 deficiency is associated with increased osteoclast activity and reduced cortical bone volume in adult male mice.

Increasing evidence emphasizes the importance of chemokines and chemokine receptors as regulators of bone remodeling. The C-C chemokine receptor 3 (CCR3) is dramatically upregulated during osteoclastogenesis, but the role of CCR3 in osteoclast formation and bone remodeling in adult mice is unknown. Herein, we used bone marrow macrophages derived from adult male CCR3-proficient and CCR3-deficient mice to study the role of CCR3 in osteoclast formation and activity. CCR3 deficiency was associated with formation of giant hypernucleated osteoclasts, enhanced bone resorption when cultured on bone slices, and altered mRNA expression of related chemokine receptors and ligands. In addition, primary mouse calvarial osteoblasts isolated from CCR3-deficient mice showed increased mRNA expression of the osteoclast activator-related gene, receptor activator of nuclear factor kappa-B ligand, and osteoblast differentiation-associated genes. Microcomputed tomography analyses of femurs from CCR3-deficient mice revealed a bone phenotype that entailed less cortical thickness and volume. Consistent with our in vitro studies, the total number of osteoclasts did not differ between the genotypes in vivo. Moreover, an increased endocortical osteoid mineralization rate and higher trabecular and cortical bone formation rate was displayed in CCR3-deficient mice. Collectively, our data show that CCR3 deficiency influences osteoblast and osteoclast differentiation and that it is associated with thinner cortical bone in adult male mice.

Lack of CCR3 leads to a skeletal phenotype only in male mice.

We recently showed that adult male mice that lacked the C-C-chemokine receptor 3 (CCR3) exhibited disturbed bone remodeling, which resulted in a cortical bone phenotype of thin femoral cortical bone. However, it remains unknown whether this phenotype would be present during bone modeling, or it affects female mice. Here, we analyzed juvenile and adolescent CCR3-deficient mice to determine when bone modeling was affected in the absence of CCR3 signaling. To investigate whether the CCR3 bone phenotype was sex-related, we analyzed both young female and male mice, and adult females. Micro-computed tomography (µCT) and histomorphometric analyses in adolescent CCR3-deficient male mice revealed reduced cortical bone volume and thickness, and an increase in periosteal mineralization. Interestingly, no skeletal phenotype was observed in adolescent or adult female CCR3-deficient mice. Among juvenile CCR3-deficient mice, neither males nor females showed a skeletal phenotype, which indicated that bone modeling was not affected by the CCR3 deficiency. In summary, adolescent and adult male mice that lacked CCR3 receptors exhibited a cortical phenotype that was not present in female mice, probably due to an estrogen protective mechanism. Based on these and our previous results, we suggest that the importance of CCR3 in cortical bone turnover is related to sex hormones. Because only a few molecules are known to control cortical bone turnover, our novel finding that CCR3 regulated cortical bone thickness only in males suggested that CCR3 is a novel target for controlling cortical bone morphology in male individuals, and perhaps, in post-menopausal women.

Simplified model for light scattering from granular materials with varying moisture content.

Reflection measurements were performed on dry and moistened sand grains and glass spheres, respectively. A simple model for determining the water content is proposed from looking at the reflection distribution in the plane of incidence. The model is a combination of two sheared cosine-functions and consists of only two parameters. One parameter controls whether the reflection is mainly in the forward or backward direction. The former is true when the water content is high and the latter is true when the material is dry. The other parameter gives an idea of the homogeneity of the material.

Phase errors due to speckles in laser fringe projection.

When measuring a three-dimensional shape with triangulation and projected interference fringes it is of interest to reduce speckle contrast without destroying the coherence of the projected light. A moving aperture is used to suppress the speckles and thereby reduce the phase error in the fringe image. It is shown that the phase error depends linearly on the ratio between the speckle contrast and the modulation of the fringes. In this investigation the spatial carrier method was used to extract the phase, where the phase error also depends on filtering the Fourier spectrum. An analytical expression for the phase error is derived. Both the speckle reduction and the theoretical expressions for the phase error are verified by simulations and experiments. It was concluded that a movement of the aperture by three aperture diameters during exposure of the image reduces the speckle contrast and hence the phase error by 60%. In the experiments, a phase error of 0.2 rad was obtained.