Viral uptake and pathophysiology of the lung endothelial cells in age-associated severe SARS-CoV-2 infection models.

Thrombosis is the major cause of death in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and the pathology of vascular endothelial cells (ECs) has received much attention. Although there is evidence of the infection of ECs in human autopsy tissues, their detailed pathophysiology remains unclear due to the lack of animal model to study it. We used a mouse-adapted SARS-CoV-2 virus strain in young and mid-aged mice. Only mid-aged mice developed fatal pneumonia with thrombosis. Pulmonary ECs were isolated from these infected mice and RNA-Seq was performed. The pulmonary EC transcriptome revealed that significantly higher levels of viral genes were detected in ECs from mid-aged mice with upregulation of viral response genes such as DDX58 and IRF7. In addition, the thrombogenesis-related genes encoding PLAT, PF4, F3 PAI-1, and P-selectin were upregulated. In addition, the inflammation-related molecules such as CXCL2 and CXCL10 were upregulated in the mid-aged ECs upon viral infection. Our mouse model demonstrated that SARS-CoV-2 virus entry into aged vascular ECs upregulated thrombogenesis and inflammation-related genes and led to fatal pneumonia with thrombosis. Current results of EC transcriptome showed that EC uptake virus and become thrombogenic by activating neutrophils and platelets in the aged mice, suggesting age-associated EC response as a novel finding in human severe COVID-19.

Dynamic morphometric changes in the mandibular osteocytic lacunae of ovariectomized rats in response to teriparatide, as revealed by three-dimensional fluorescence analyses: Possible involvement of osteocytic perilacunar remodeling.

OBJECTIVES: Teriparatide [TPTD; human parathyroid hormone (hPTH)] is an anti-osteoporotic drug with bone anabolic effects. Clinical and preclinical studies have indicated that TPTD has value in oral and maxillofacial bone therapies, including jawbone regeneration, periodontal tissue repair, and the treatment of medication-related osteonecrosis of the jaw. However, it is unclear whether the craniofacial bones respond to TPTD similarly to the axial and appendicular bones. Recent studies showed that TPTD acts on both osteocytes and osteoblasts. This study aimed to characterize distinct craniofacial bone sites, with a focus on morphometric changes in osteocytic lacunae in ovariectomized rats receiving TPTD. METHODS: Conventional bone histomorphometric analyses of mandibular and parietal bone sections were conducted. High-resolution confocal imaging-based three-dimensional fluorescence morphometric analyses of osteocytic lacunae in distinct mandibular and parietal bone sites were conducted. RESULTS: We observed dynamic changes in the morphometric characteristics of osteocytic lacunae specifically in alveolar and other mandibular bone sites upon TPTD administration. CONCLUSIONS: These findings suggest that osteocytes in mandibular bone (specifically, alveolar bone) have unique functional characteristics of osteocytic perilacunar remodeling.

Evaluation of cortical bone remodeling in canines treated with daily and weekly administrations of teriparatide by establishing AI-driven morphometric analyses and GIS-based spatial mapping.

Larger animal models with a well-developed Haversian system, as observed in humans, are ideal to analyze cortical bone remodeling in pharmacological studies of anti-osteoporosis drugs, although they have some limitations in controlling individual variability in size, weight, age, and number. This study aimed to morphometrically analyze cortical bone remodeling focusing on Haversian canals in dogs using four regimens of TPTD with daily and weekly administrations at lower and higher weekly doses (4.9 µg/kg/week and 19.8 µg/kg/week, respectively) for 9 months. A micro-computed tomography-based analysis showed no significant differences among regimen groups. By establishing artificial intelligence (AI)-driven morphometric analyses and geographical information system (GIS)-based spatial mapping of Haversian canals that does not require confocal microscopy but is possible with more commonly used wide field microscopes, we successfully observed significant morphometric distinctions among regimens applied even in dogs. Our analytical results suggested that the daily higher regimen specifically increased the number of eroded pores creating spaces between existing canals, thus stimulating cortical bone remodeling.

Centrosome clustering control in osteoclasts through CCR5-mediated signaling.

Osteoclasts uniquely resorb calcified bone matrices. To exert their function, mature osteoclasts maintain the cellular polarity and directional vesicle trafficking to and from the resorbing bone surface. However, the regulatory mechanisms and pathophysiological relevance of these processes remain largely unexplored. Bone histomorphometric analyses in Ccr5-deficient mice showed abnormalities in the morphology and functional phenotype of their osteoclasts, compared to wild type mice. We observed disorganized clustering of nuclei, as well as centrosomes that organize the microtubule network, which was concomitant with impaired cathepsin K secretion in cultured Ccr5-deficient osteoclasts. Intriguingly, forced expression of constitutively active Rho or Rac restored these cytoskeletal phenotypes with recovery of cathepsin K secretion. Furthermore, a gene-disease enrichment analysis identified that PLEKHM1, a responsible gene for osteopetrosis, which regulates lysosomal trafficking in osteoclasts, was regulated by CCR5. These experimental results highlighted that CCR5-mediated signaling served as an intracellular organizer for centrosome clustering in osteoclasts, which was involved in the pathophysiology of bone metabolism.

Potential relationship between the dosage of prednisolone and delayed healing at tooth extraction: A retrospective study.

Background/purpose: Delayed healing of the extraction socket is not uncommon when tooth extraction is performed on patients taking prednisolone. This study aimed to identify specific dosage of prednisolone and factors associated with delayed healing of the extraction socket in patients taking prednisolone. Materials and methods: This single-center retrospective study included 80 patients who underwent tooth extraction under local anesthesia and were taking prednisolone orally. Patients were divided into the nondelayed healing group (n = 50) and delayed healing group (n = 30), and their background and dosage of prednisolone were compared. Results: The dosage of prednisolone was significantly higher in the delayed healing group than in the nondelayed healing group. A receiver operating characteristics curve analysis resulted in moderate accuracy when the cutoff value was set at 8.0, with 67% sensitivity, 76% specificity, and 0.765 area under the curve. The multivariate logistic regression analysis revealed that prednisolone dosage >8.0 mg/day (odds ratio [OR], 10.8; 95% confidence interval [CI], 2.79-41.6) and osteosclerotic changes beyond the alveolar bone around the tooth to be extracted (OR, 10.3; 95% CI, 2.81-37.8) in X-ray imaging had significant effects on delayed healing. Conclusion: The results of this study suggested that delayed healing following tooth extractions in patients taking prednisolone was related to a dosage of 8.0 mg/day or higher and osteosclerotic changes.

Skeletal-Vascular Interactions in Bone Development, Homeostasis, and Pathological Destruction.

Bone is a highly vascularized organ that not only plays multiple roles in supporting the body and organs but also endows the microstructure, enabling distinct cell lineages to reciprocally interact. Recent studies have uncovered relevant roles of the bone vasculature in bone patterning, morphogenesis, homeostasis, and pathological bone destruction, including osteoporosis and tumor metastasis. This review provides an overview of current topics in the interactive molecular events between endothelial cells and bone cells during bone ontogeny and discusses the future direction of this research area to find novel ways to treat bone diseases.

Association between an Increased Serum CCL5 Level and Pathophysiology of Degenerative Joint Disease in the Temporomandibular Joint in Females.

Degenerative joint disease of the temporomandibular joints (DJD-TMJ) clinically manifests with symptoms such as orofacial pain, joint sounds and limited jaw movements. Our research group previously reported the functional necessity of a chemokine-chemokine receptor axis of CCL5-CCR5 in osteoclasts. Accumulated studies reported that this axis was involved in the pathogenesis of bone and joint destructive diseases, suggesting CCL5 as a potent biomarker. This study investigated whether or not the serum level of CCL5 can be a biomarker of DJD-TMJ and concomitantly analyzed changes in the serum and urine levels of bone markers to see whether or not changes in the rate of bone metabolism were predisposing. We enrolled 17 female subjects with diagnosed DJD-TMJ and sexually and age-matched 17 controls. The serum CCL5 level in DJD-TMJ subjects was significantly higher than that in the control subjects. Multivariate analyses indicated an association between an augmented CCL5 level and the rate of bone metabolism, especially in relatively young DJD-TMJ subjects without other systemic symptoms. A principal component analysis of serum markers and our pharmacological experiment using a postmenopausal model of ovariectomized rats suggested that an augmented serum CCL5 level specifically reflected DJD-TMJ and that covert changes in the rate of bone metabolism predisposed individuals to DJD-TMJ.

Ethyl loflazepate as a treatment for patients with idiopathic and psychogenic taste disorder.

BACKGROUND: Ethyl loflazepate (EL) is a benzodiazepine derivative that has been reported to activate the gustatory cortex. Our department routinely uses EL as a first-line treatment for idiopathic and psychogenic taste disorders, although little has been reported in the literature with respect to patient outcomes, so we conducted a retrospective study examining its safety and efficacy. METHODS: Between 2008 and 2020, 49 patients (14 males and 35 females; mean age, 62.1 years) were diagnosed with taste disorders and received EL as their only treatment for > 14 days. Severity of taste disorder was evaluated using the paper disc method by Sakai et al., and treatment efficacy was evaluated using the Visual Analog Scale, wherein patients gave subjective ratings for their symptoms (reductions by > 50% after administration of EL for 4 weeks were defined as improvements). RESULTS: Results showed that the improvement rates for patients with idiopathic and psychogenic taste disorders were 55 and 70%, respectively. Additionally, the majority (78%) improved within 2 weeks, and side effects were mild (seven cases with drowsiness and one case with dizziness). CONCLUSIONS: We conclude that EL is an appropriate first-line medication for patients with idiopathic and psychogenic taste disorders.