BonePub Date : 2022-12-01DOI: 10.2139/ssrn.4232740
Laura Peurière, Carmelo J Mastrandrea, A. Vanden‐Bossche, M. Linossier, M. Thomas, Myriam Normand, M. Lafage-Proust, L. Vico
{"title":"Hindlimb unloading in C57BL/6J mice induces bone loss at thermoneutrality without change in osteocyte and lacuno-canalicular network.","authors":"Laura Peurière, Carmelo J Mastrandrea, A. Vanden‐Bossche, M. Linossier, M. Thomas, Myriam Normand, M. Lafage-Proust, L. Vico","doi":"10.2139/ssrn.4232740","DOIUrl":"https://doi.org/10.2139/ssrn.4232740","url":null,"abstract":"Impaired mechanical stimuli during hindlimb unloading (HLU) are believed to exacerbate osteocyte paracrine regulation of osteoclasts. We hypothesized that bone loss and deterioration of the osteocyte lacuno-canalicular network are attenuated in HLU mice housed at thermoneutrality (28 °C) compared with those housed at ambient temperature (22 °C). Following acclimatization, 20-week-old male C57BL/6J mice were submitted to HLU or kept in pair-fed control cages (CONT), for 5 days (5d) or 14d, at 22 °C or 28 °C. In the femur distal metaphysis, thermoneutral CONT mice had higher bone volume (p = 0.0007, BV/TV, in vivo μCT, vs. 14dCONT22) whilst osteoclastic surfaces of CONT and HLU were greater at 22 °C (5dCONT22 + 53 %, 5dHLU22 + 50 %, 14dCONT22 + 186 %, 14dHLU22 + 104 %, vs matching 28 °C group). In the femur diaphysis and at both temperatures, 14dHLU exhibited thinner cortices distally or proximally compared to controls; the mid-diaphysis being thicker at 28 °C than at 22 °C in all groups. Expression of cortical genes for proteolytic enzyme (Mmp13), markers for osteoclastogenic differentiation (MCSF, RANKL), and activity (TRAP, Ctsk) were increased following 22 °C HLU, whereas only Ctsk expression was increased following 28 °C HLU. Expression of cortical genes for apoptosis, senescence, and autophagy were not elevated following HLU at any temperature. Osteocyte density at the posterior mid-diaphysis was similar between groups, as was the proportion of empty lacunae (<0.5 %). However, analysis of the lacuno-canalicular network (LCN, fluorescein staining) revealed unstained areas in the 14dHLU22 group only, suggesting disrupted LCN flow in this group alone. In conclusion, 28 °C housing influences the HLU bone response but does not prevent bone loss. Furthermore, our results do not show osteocyte senescence or death, and at thermoneutrality, HLU-induced bone resorption is not triggered by osteoclastic activators RANKL and MCSF.","PeriodicalId":93913,"journal":{"name":"Bone","volume":"1 1","pages":"116640"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42369205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
BonePub Date : 2022-12-01DOI: 10.2139/ssrn.4263596
M. Bie, Yi Tang, Yuxing Xia, Q. Zhang, Yuanye Tian, Chun Cheng, Xinzhao Li, Xin Qi, F. Kang
{"title":"HIF-1α mediates osteoclast-induced disuse osteoporosis via cytoophidia in the femur of mice.","authors":"M. Bie, Yi Tang, Yuxing Xia, Q. Zhang, Yuanye Tian, Chun Cheng, Xinzhao Li, Xin Qi, F. Kang","doi":"10.2139/ssrn.4263596","DOIUrl":"https://doi.org/10.2139/ssrn.4263596","url":null,"abstract":"Osteoporosis induced by disuse because of bed rest or the aerospace industry has become one of the most common skeletal disorders. However, mechanisms underlying the disuse osteoporosis remain largely unknown. We validated the tail-suspended model in mice and demonstrated that there is bone loss in the trabecular and cortical bones of the femur. Importantly, we showed that genetical deletion of hypoxia-inducible factor-1α (HIF-1α) in osteoclasts ameliorated osteoclastic bone resorption in the trabecular bone whereas pharmacological treatment with HIF-1α inhibitor protected the hindlimb-unloaded mice from disuse-induced osteoporosis in the trabecular and cortical bones. The HIF-1α knockout RAW264.7 cells and RNA-sequencing proved that HIF-1α is vital for osteoclastogenesis and bone resorption because it regulated the level of inosine monophosphate dehydrogenase (IMPDH) and cytidine triphosphate synthetase (CTPS) via cellular myelocytomatosis (c-Myc) oncogene. The IMPDH and CTPS are vital nucleotide metabolic enzymes which have an important functional role in cell metabolism, and they can assemble into intracellular linear or ring-shaped structures to cope with cell stress. Interestingly, both in vitro and in vivo, the IMPDH and CTPS cytoophidia were found in osteoclasts, and the level of HIF-1α correlated with osteoclastogenesis and bone-resorbing activity. Our data revealed that HIF-1α/c-Myc/cytoophidia signalling might be required for osteoclasts to mediate cell metabolism in disuse-induced osteoporosis. Overall, our results revealed a new role of HIF-1α/c-Myc/cytoophidia in supporting osteoclastogenesis and bone resorption and exposed evidence for its role in the pathogenesis of disuse osteoporosis, which might provide promising therapeutic targets.","PeriodicalId":93913,"journal":{"name":"Bone","volume":"168 1","pages":"116648"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42434262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Diagnostic markers of metabolic bone disease of prematurity in preterm infants.","authors":"Kui-lin Lü, Shuang-shuang Xie, Qi-Feng Hu, Zhang-Ya Yang, Qiong-li Fan, Enhao Liu, Yu-Ping Zhang","doi":"10.2139/ssrn.4259998","DOIUrl":"https://doi.org/10.2139/ssrn.4259998","url":null,"abstract":"Due to the higher birth rate of preterm infants and improvements in their management, metabolic bone disease of prematurity (MBDP) has a high incidence and is receiving increasing attention. Bone growth and mineralization are important for normal growth and development. However, clear indicators for the early diagnosis of MBDP are lacking. We aimed to explore simple and feasible early warning indicators for diagnosing MBDP. Our study collected case data of premature infants from two medical centers in Chongqing from January 2020 to February 2022. According to the inclusion and exclusion criteria, data from 136 cases were collected. The correlation between 14 variables in each case and the occurrence of MBDP was analyzed. According to the area under the receiver operating characteristic curve (AUROC) analysis, the best cutoff value for each variable was determined. Potential predictors were selected and LASSO regression analysis was used to establish the association of two models with MBDP, whose results were used to develop a diagnostic nomogram. Furthermore, a model decision curve was analyzed. Four predictors were selected from 14 clinical variables by LASSO regression, and Model I was established, including the following characteristics: height (>36 cm), head circumference (≤29.49 cm), and Ca2+ (>2.13 mmol/L) and alkaline phosphatase (ALP) (>344 U/L) levels. A single predictor, the ALP level (>344 U/L), was used to establish Model II. The AUROC values of the two models were 0.959 for Model I and 0.929 for Model II. In conclusion, in this study, two diagnostic models of MBDP were developed using four combinations of predictors and ALP as a single predictor. Both models showed a strong sensitivity and specificity for the early diagnosis of metabolic bone disease (MBD) and an ALP level of 344 U/L was defined as a simple and effective diagnostic threshold. In future studies, the evaluation of larger sample sizes, the establishment of diagnostic threshold values of ALP for premature infants of different ages, and internal and external validations are needed to improve the adaptability of the model.","PeriodicalId":93913,"journal":{"name":"Bone","volume":"1 1","pages":"116656"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44353501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
BonePub Date : 2022-12-01DOI: 10.2139/ssrn.4207532
T. Stauber, Lena Wartosch, Svenja Vishnolia, A. Schulz, U. Kornak
{"title":"CLCN7, a gene shared by autosomal recessive and autosomal dominant osteopetrosis.","authors":"T. Stauber, Lena Wartosch, Svenja Vishnolia, A. Schulz, U. Kornak","doi":"10.2139/ssrn.4207532","DOIUrl":"https://doi.org/10.2139/ssrn.4207532","url":null,"abstract":"After the discovery of abundant v-ATPase complexes in the osteoclast ruffled membrane it was obvious that in parallel a negative counter-ion needs to be transported across this membrane to allow for efficient transport of protons into the resorption lacuna. While different candidate proteins were discussed the osteopetrosis phenotype of Clcn7 knockout mice suggested that the chloride/proton-exchanger ClC-7 might be responsible for transporting the negative charge. In the following, individuals with autosomal recessive osteopetrosis (ARO) were found to carry biallelic CLCN7 pathogenic variants. Shortly thereafter, heterozygous pathogenic variants were identified as the exclusive cause of autosomal dominant osteopetrosis type 2 (ADO2). Since in most cell types other than osteoclasts ClC-7 resides in late endosomes and lysosomes, it took some time until the electrophysiological properties of ClC-7 were elucidated. Whereas most missense variants lead to reduced chloride currents, several variants with accelerated kinetics have been identified. Evidence for folding problems is also known for several missense variants. Paradoxically, a heterozygous activating variant in ClC-7 was described to cause lysosomal alteration, pigmentation defects, and intellectual disability without osteopetrosis. The counter-intuitive 2 Cl-/H+ exchange function of ClC-7 was shown to be physiologically important for intravesicular ion homeostasis. The lysosomal function of ClC-7 is also the reason why individuals with CLCN7-ARO can develop a storage disorder and neurodegeneration, a feature that is variable and difficult to predict. Furthermore, the low penetrance of heterozygous pathogenic CLCN7 variants and the clinical variability of ADO2 are incompletely understood. We aim to give an overview not only of the current knowledge about ClC-7 and its related pathologies, but also of the scientists and clinicians that paved the way for these discoveries.","PeriodicalId":93913,"journal":{"name":"Bone","volume":"1 1","pages":"116639"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42002337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
BonePub Date : 2022-11-08DOI: 10.2139/ssrn.4130780
Matthias Walle, Dominic Eggemann, P. Atkins, Jack J. Kendall, K. Stock, Ralph Müller, C. Collins
{"title":"Motion grading of high-resolution quantitative computed tomography supported by deep convolutional neural networks.","authors":"Matthias Walle, Dominic Eggemann, P. Atkins, Jack J. Kendall, K. Stock, Ralph Müller, C. Collins","doi":"10.2139/ssrn.4130780","DOIUrl":"https://doi.org/10.2139/ssrn.4130780","url":null,"abstract":"Image quality degradation due to subject motion confounds the precision and reproducibility of measurements of bone density, morphology and mechanical properties from high-resolution peripheral quantitative computed tomography (HR-pQCT). Time-consuming operator-based scoring of motion artefacts remains the gold standard to determine the degree of acceptable motion. However, due to the subjectiveness of manual grading, HR-pQCT scans of poor quality, which cannot be used for analysis, may be accepted upon initial review, leaving patients with incomplete or inaccurate imaging results. Convolutional Neural Networks (CNNs) enable fast image analysis with relatively few pre-processing requirements in an operator-independent and fully automated way for image classification tasks. This study aimed to develop a CNN that can predict motion scores from HR-pQCT images, while also being aware of uncertain predictions that require manual confirmation. The CNN calculated motion scores within seconds and achieved a high F1-score (86.8 ± 2.8 %), with good precision (87.5 ± 2.7 %), recall (86.7 ± 2.9 %) and a substantial agreement with the ground truth measured by Cohen's kappa (κ = 68.6 ± 6.2 %); motion scores of the test dataset were predicted by the algorithm with comparable accuracy, precision, sensitivity and agreement as by the operators (p > 0.05). This post-processing approach may be used to assess the effect of motion scores on microstructural analysis and can be immediately implemented into clinical protocols, significantly reducing the time for quality assessment and control of HR-pQCT scans.","PeriodicalId":93913,"journal":{"name":"Bone","volume":"1 1","pages":"116607"},"PeriodicalIF":0.0,"publicationDate":"2022-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49382975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
BonePub Date : 2022-11-01DOI: 10.2139/ssrn.4214482
Yuri Seki, H. Takebe, T. Mizoguchi, Hiroaki Nakamura, M. Iijima, K. Irie, A. Hosoya
{"title":"Differentiation ability of Gli1+ cells during orthodontic tooth movement.","authors":"Yuri Seki, H. Takebe, T. Mizoguchi, Hiroaki Nakamura, M. Iijima, K. Irie, A. Hosoya","doi":"10.2139/ssrn.4214482","DOIUrl":"https://doi.org/10.2139/ssrn.4214482","url":null,"abstract":"Orthodontic tooth movement (OTM) induces bone formation on the alveolar bone of the tension side; however, the mechanism of osteoblast differentiation is not fully understood. Gli1 is an essential transcription factor for hedgehog signaling and functions in undifferentiated cells during embryogenesis. In this study, we examined the differentiation of Gli1+ cells in the periodontal ligament (PDL) during OTM using a lineage-tracing analysis. After the final administration of tamoxifen for 2 days to 8-week-old Gli1-CreERT2/ROSA26-loxP-stop-loxP-tdTomato (iGli1/Tomato) mice, Gli1/Tomato+ cells were rarely observed near endomucin+ blood vessels in the PDL. Osteoblasts lining the alveolar bone did not exhibit Gli1/Tomato fluorescence. To move the first molar of iGli1/Tomato mice medially, nickel-titanium closed-coil springs were attached between the upper anterior alveolar bone and the first molar. Two days after OTM initiation, the number of Gli1/Tomato+ cells increased along with numerous PCNA+ cells in the PDL of the tension side. As some Gli1/Tomato+ cells exhibited positive expression of osterix, an osteoblast differentiation marker, Gli1+ cells probably differentiated into osteoblast progenitor cells. On day 10, the newly formed bone labeled by calcein administration during OTM was detected on the surface of the original alveolar bone of the tension side. Gli1/Tomato+ cells expressing osterix localized to the surface of the newly formed bone. In contrast, in the PDL of the compression side, Gli1/Tomato+ cells proliferated before day 10 and expressed type I collagen, suggesting that the Gli1+ cells also differentiated into fibroblasts. Collectively, these results demonstrate that Gli1+ cells in the PDL can differentiate into osteoblasts at the tension side and may function in bone remodeling as well as fibril formation in the PDL during OTM.","PeriodicalId":93913,"journal":{"name":"Bone","volume":"1 1","pages":"116609"},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45723494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
BonePub Date : 2022-11-01DOI: 10.2139/ssrn.4239423
A. Esposito, M. Klüppel, Brittany M. Wilson, S. K. Meka, A. Spagnoli
{"title":"CXCR4 mediates the effects of IGF-1R signaling in rodent bone homeostasis and fracture repair.","authors":"A. Esposito, M. Klüppel, Brittany M. Wilson, S. K. Meka, A. Spagnoli","doi":"10.2139/ssrn.4239423","DOIUrl":"https://doi.org/10.2139/ssrn.4239423","url":null,"abstract":"Non-union fractures have considerable clinical and economic burdens and yet the underlying pathogenesis remains largely undetermined. The fracture healing process involves cellular differentiation, callus formation and remodeling, and implies the recruitment and differentiation of mesenchymal stem cells that are not fully characterized. C-X-C chemokine receptor 4 (CXCR4) and Insulin-like growth factor 1 receptor (IGF-1R) are expressed in the fracture callus, but their interactions still remain elusive. We hypothesized that the regulation of CXCR4 by IGF-1R signaling is essential to maintain the bone homeostasis and to promote fracture repair. By using a combination of in vivo and in vitro approaches, we found that conditional ablation of IGF-1R in osteochondroprogenitors led to defects in bone formation and mineralization that associated with altered expression of CXCR4 by a discrete population of endosteal cells. These defects were corrected by AMD3100 (a CXCR4 antagonist). Furthermore, we found that the inducible ablation of IGF-1R in osteochondroprogenitors led to fracture healing failure, that associated with an altered expression of CXCR4. In vivo AMD3100 treatment restored fracture healing and normalized CXCR4 expression. Moreover, we determined that these effects were mediated through the IGF-1R/Insulin receptor substrate 1 (IRS-1) signaling pathway. Taken together, our studies identified a novel population of endosteal cells that is functionally regulated through the modulation of CXCR4 by IGF-1R signaling, and such control is essential in bone homeostasis and fracture healing. Knowledge gained from these studies has the potential to accelerate the development of novel therapeutic interventions by targeting CXCR4 signaling to treat non-unions.","PeriodicalId":93913,"journal":{"name":"Bone","volume":"1 1","pages":"116600"},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41937622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
BonePub Date : 2022-11-01DOI: 10.2139/ssrn.4212322
V. De Martino, J. Pepe, Federica Biamonte, L. Colangelo, Laura Di Giuseppe, L. Nieddu, M. Occhiuto, S. Minisola, C. Cipriani
{"title":"Impairment in muscle strength and its determinants in primary hyperparathyroidism: A study in postmenopausal women.","authors":"V. De Martino, J. Pepe, Federica Biamonte, L. Colangelo, Laura Di Giuseppe, L. Nieddu, M. Occhiuto, S. Minisola, C. Cipriani","doi":"10.2139/ssrn.4212322","DOIUrl":"https://doi.org/10.2139/ssrn.4212322","url":null,"abstract":"Neuromuscular impairment is described among the non-classical complications of primary hyperparathyroidism (PHPT). However, the extent of this complications and related mechanisms have not been fully addressed. The study aimed at assessing muscle strength and its main determinants in postmenopausal women with PHPT. We studied 48 postmenopausal women with PHPT (mean age 60.8 ± 5.6 SD years; BMI 25.6 ± 5.5 kg/m2) and 38 healthy postmenopausal women (mean age 58.6 ± 5.9; BMI 25.2 ± 3.5). In all subjects, the maximum voluntary contraction (MVC, Newton, N) was measured by Hand held Dynamometer (Kayser Italia srl, Livorno, Italy) and the lumbar spine, total hip, femoral neck, and non dominant distal one-third radius areal BMD (aBMD) by dual X-ray absorptiometry (DXA) (Hologic, Waltham, MA). Serum ionized calcium (Ca++), parathyroid hormone (PTH), phosphorus (P), and 25-hydroxyvitaminD [25 (OH)D] levels were measured in both groups. A subgroup of 30 PHPT women agreed to participate to the follow-up sub-study and were re-assessed 24 months after parathyroidectomy (n = 15) or after baseline evaluation (n = 15). Patients with PHPT had significant lower MVC values compared to healthy women (p < 0.001). As expected, serum Ca++ and PTH levels were higher and P lower in PHPT compared to controls. We observed a significant association between MVC and total hip and one-third radius aBMD (R = 0.320 and 0.370, p < 0.05) and negative association with Ca++ (R = -0.340, p < 0.05) in the PHPT group; MVC was positively associated with one-third radius aBMD (R = 0.360, p < 0.05) and negatively with age, BMI and myostatin (R = -0.390, -0.340 and -0.450, p < 0.05) in the group of healthy women. The linear model using BMI, Ca++, P, 25 (OH) D, PTH, myostatin, and aBMD as covariates showed that one-third radius aBMD was positively associated with MVC in PHPT patients (p < 0.02) and in healthy subjects (p < 0.001). Additionally, serum PTH and myostatin were negatively associated with MVC in healthy subjects (p < 0.03 and p < 0.01). The linear model showed that surgery was associated with an increase in MVC (p < 0.05) in PHPT patients after 24 months, all other variables being equal and by controlling for baseline values of MVC. Handgrip strength is significantly impaired in postmenopausal women with PHPT. Some common mechanisms influencing muscle function exist in PHPT and in healthy subjects; they are associated with the reduced aBMD at cortical sites. Hypercalcemia seems to be one of the main determinants of impairment in muscle strength in PHPT, while no role is played by myostatin.","PeriodicalId":93913,"journal":{"name":"Bone","volume":"1 1","pages":"116604"},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43246826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
BonePub Date : 2022-11-01DOI: 10.2139/ssrn.4163454
Qian Chen, Ziteng Wang, Chengyu Yang, Baochen Li, Xingxing Ren, Chao Liu, Lei Xi
{"title":"High resolution intravital photoacoustic microscopy reveals VEGF-induced bone regeneration in mouse tibia.","authors":"Qian Chen, Ziteng Wang, Chengyu Yang, Baochen Li, Xingxing Ren, Chao Liu, Lei Xi","doi":"10.2139/ssrn.4163454","DOIUrl":"https://doi.org/10.2139/ssrn.4163454","url":null,"abstract":"Osteogenesis and angiogenesis are essential for bone homeostasis and repair. Newly formed vessels convey osteogenic progenitors during bone regeneration. However, the lack of continuous and label-free visualization of the bone microvasculature has resulted in little understanding of the neovascular dynamics. Here, we take advantage of optical-resolution photoacoustic microscopy (ORPAM) for label-free, intravital, long-term observation of the bone vascular dynamics, including angiogenesis, remodeling and quantified angiogenic effect of locally-applied vascular endothelial growth factor (VEGF) in the murine tibial defect model. We employed ex vivo confocal microscopy and micro-computed tomography (micro-CT) imaging to verify the positive role of VEGF treatment. VEGF treatment increased the concentration of total hemoglobin, vascular branching, and vascular density, which correlated with more osteoprogenitors and increased bone formation within the defect. These data demonstrated ORPAM as a useful imaging tool that detected functional capillaries to understand hemodynamics, and revealed the effectiveness of locally delivered therapeutic agents with sufficient sensitivity, contributing to the understanding of spatiotemporal regulatory mechanisms on blood vessels during bone regeneration.","PeriodicalId":93913,"journal":{"name":"Bone","volume":"1 1","pages":"116631"},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42209944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
BonePub Date : 2022-10-01DOI: 10.2139/ssrn.4132889
Nishitha R Pillai, A. Aggarwal, Paulina Orchard
{"title":"Phenotype-autosomal recessive osteopetrosis.","authors":"Nishitha R Pillai, A. Aggarwal, Paulina Orchard","doi":"10.2139/ssrn.4132889","DOIUrl":"https://doi.org/10.2139/ssrn.4132889","url":null,"abstract":"Osteopetrosis (OPT) is a life-threatening disease characterized by increased bone mass caused by diminished osteoclast function/differentiation. The autosomal recessive forms, caused by biallelic variants in implicated genes, usually present in infancy. Without treatment, autosomal recessive OPTs are usually fatal within the first 10 years of life [1]. Here, we review the clinical features and associated pathophysiology of the autosomal recessive OPT. A greater understanding of these rare disorders will advance early diagnosis and optimal management.","PeriodicalId":93913,"journal":{"name":"Bone","volume":"1 1","pages":"116577"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45411040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}