Combined degenerative and regenerative remodeling responses of the mandibular condyle to experimentally induced disordered occlusion.

INTRODUCTION: The purposes of this research were to investigate the long-term responses of mandibular condylar cartilage to experimentally induced disordered occlusion and to evaluate changes in the expression of the SDF-1/CXCR4 axis. METHODS: Experimentally induced disordered occlusions were created in 8-week-old female Sprague-Dawley rats by orthodontic methods. After 24 weeks, remodeling of the mandibular condylar cartilage was assessed by hematoxylin and eosin staining. Protein and mRNA expression of SDF-1, CXCR4, MMP9, IL6, OPG, and RANKL were investigated by means of immunohistochemical staining and real-time polymerase chain reaction. RESULTS: Obvious cartilage degenerative remodeling responses were observed; they appeared as uneven distributions of cellular disposition, loss of cartilage surface integrity, and cell-free areas. Regenerative responses presenting as thickening of the whole and the calcified cartilage layers in the experimental group were also observed. Compared with the age-matched controls, the protein and mRNA levels of SDF-1, CXCR4, MMP9, IL6, and OPG, but not RANKL, were increased in the experimental group (all, P <0.05). In addition, the mRNA level of RANKL/OPG showed a decreasing trend in the experimental group compared with the age-matched controls (P = 0.052). CONCLUSIONS: This study demonstrated that long-term experimentally induced disordered occlusion leads to a combined response in degeneration and regeneration of mandibular cartilage, accompanied by active interaction of the SDF-1/CXCR4 axis and local upregulation of MMP9, IL6, and OPG.

Inflammation-mediated age-dependent effects of casein kinase 2-interacting protein-1 on osteogenesis in mesenchymal stem cells.

BACKGROUND: The casein kinase 2-interacting protein-1 (CKIP-1) is important in the development of osteoblasts and cardiomyocytes. However, the effects of CKIP-1 on osteoblast precursor mesenchymal stem cells (MSCs) remain unclear. This study aimed to determine whether CKIP-1 affects osteogenic differentiation in MSCs and explore the relationship of CKIP-1 and inflammation. METHODS: Bone marrow MSCs of CKIP-1 wild type (WT) and knockout (KO) mice were cultivated in vitro. Cell phenotype was analyzed by flow cytometry, colony formation was detected to study the proliferative ability. Osteogenic and adipogenic induction were performed. The osteogenic ability was explored by alizarin red staining, alkaline phosphatase (ALP) staining and ALP activity detection. Quantitative real-time polymerase chain reaction (qRT-PCR) was carried out to determine the mRNA expression levels of osteoblast marker genes. The adipogenic ability was detected by oil red O staining. Content of the bone was analyzed to observe the differences of bone imaging parameters including trabecular bone volume/tissue volume (BV/TV), bone surface area fraction/trabecular BV, trabecular number (Tb.N), and trabecular spacing (Tb.sp). Interleukin (IL)-1ß was injected on WT mice of 2 months old and 18 months old, respectively. Difference in CKIP-1 expression was detected by RT-PCR and western blot. The relationship between CKIP-1 and inflammation was explored by RT-PCR and western blot. RESULTS: ALP assays, alizarin red staining, and qRT-PCR showed that MSCs derived from CKIP-1 KO mice exhibited a stronger capability for osteogenesis. Micro-computed tomography detection showed that among 18-month-old mice, CKIP-1 KO mice presented significantly higher bone mass compared with WT mice (P = 0.02). No significant difference was observed in 2-month-old mice. In vivo data showed that expression of CKIP-1 was higher in the bone marrow of aging mice than in young mice (4.3-fold increase at the mRNA level, P = 0.04). Finally, the expression levels of CKIP-1 in bone marrow (3.2-fold increase at the mRNA level, P = 0.03) and cultured MSCs were up-regulated on chronic inflammatory stimulation by IL-1ß. CONCLUSIONS: CKIP-1 is responsible for negative regulation of MSC osteogenesis with age-dependent effects. Increasing levels of inflammation with aging may be the primary factor responsible for higher expression levels of CKIP-1 but may not necessarily affect MSC aging.

[Patients' experiences with the Forsus appliance].

PURPOSE: To investigate patients' experiences with the Forsus appliance. METHODS: This questionnaire survey was focused on patients' comprehensive experiences with Forsus, both initially and after several months of wearing, including the patients' overall impressions of the appliance. The survey was conducted in 64 patients wearing Forsus. RESULTS: A high percentage of patients(83.7%) reported neutral to favorable experience with Forsus. 85.4% of patients reported gradual adaption to the appliance within 4 weeks. Cheek irritation was the most serious side effect (about 52%). Cheek irritation and other side effect disappeared over time. CONCLUSIONS: The Forsus appliance is relatively well accepted by patients. Most patients experience some discomfort and functional limitations at first. However, the side effect gradually diminishes with time, and the patients adapt to the appliance finally. Practitioners should be especially vigilant about problems of cheek irritation.

What interests them in the pictures?--differences in eye-tracking between rhesus monkeys and humans.

Studies estimating eye movements have demonstrated that non-human primates have fixation patterns similar to humans at the first sight of a picture. In the current study, three sets of pictures containing monkeys, humans or both were presented to rhesus monkeys and humans. The eye movements on these pictures by the two species were recorded using a Tobii eye-tracking system. We found that monkeys paid more attention to the head and body in pictures containing monkeys, whereas both monkeys and humans paid more attention to the head in pictures containing humans. The humans always concentrated on the eyes and head in all the pictures, indicating the social role of facial cues in society. Although humans paid more attention to the hands than monkeys, both monkeys and humans were interested in the hands and what was being done with them in the pictures. This may suggest the importance and necessity of hands for survival. Finally, monkeys scored lower in eye-tracking when fixating on the pictures, as if they were less interested in looking at the screen than humans. The locations of fixation in monkeys may provide insight into the role of eye movements in an evolutionary context.