Iatrogenic pseudoaneurysm rupture of the middle cerebral artery after an intracranial pressure monitor placement: a case report and literature review.

Thalamic hemorrhage (TH) is a devastating disease with a high mortality rate; however, no specific form of therapy has been proven to reduce mortality. Patients with hemorrhagic stroke undergo intracranial pressure (ICP) monitoring. However, cases involving pseudoaneurysms caused by ICP monitoring in patients with intracerebral hemorrhage have not been reported previously. Here, we report a case of pseudoaneurysm caused by an ICP monitor that was fitted due to hypertensive cerebral hemorrhage.

The interactions between mTOR and NF-κB: A novel mechanism mediating mechanical stretch-stimulated osteoblast differentiation.

Mechanical stretch is known to promote osteoblast differentiation in vitro and accelerate bone regeneration in vivo, whereas the relevant mechanism remains unclear. Recent studies have shown the importance of reciprocal interactions between mammalian target of rapamycin (mTOR) and nuclear factor kappa B (NF-κB; two downstream molecules of Akt) in the regulation of tumor cells. Thus, we hypothesize that mTOR and NF-κB as well as their interconnection play a critical role in mediating stretch-induced osteogenic differentiation in osteoblasts. We herein found that mechanical stretch (10% elongation at six cycles/min) significantly promoted the expression of osteoblast differentiation-related markers (including ALP, BMP2, Col1α, OCN, and Runx2) in osteoblast-like MG-63 cells, accompanied by increased mTOR phosphorylation and NF-κB p65 phosphorylation and nuclear translocation. Blockade of mTOR by antagonist or small interfering RNA suppressed osteogenesis-related gene expression in response to mechanical stretch, whereas inhibition of NF-κB further increased stretch-induced osteoblast differentiation. Moreover, inhibition of mTOR decreased the phosphorylation of NF-κB, and blockade of NF-κB reduced the mTOR activation in MG63 cells under mechanical stretch. Coinhibition of mTOR and NF-κB abolishes the alteration of osteogenic differentiation induced by single mTOR or NF-κB inhibition under mechanical stretch, which is equivalent to the noninhibition level for osteoblasts under mechanical stretch. The expression levels of osteogenic differentiation in osteoblasts after inhibition of Akt were similar to those after co-inhibition of mTOR and NF-κB under mechanical stretch. This study for the first time reveals the reciprocal interconnection between mTOR and NF-κB in osteoblasts under mechanical stretch and indicates that mTOR and NF-κB as well as their interactions play a key role in the regulation of cellular homeostasis of osteoblasts in response to mechanical stretch. These findings are helpful for enriching our basic knowledge of the molecular mechanisms of osteoblast mechanotransduction, and also providing insight into the clinical therapeutic modality associated with mechanical stretch (e.g., distraction osteogenesis).

Pulsed electromagnetic fields promote in vitro osteoblastogenesis through a Wnt/ß-catenin signaling-associated mechanism.

Substantial evidence indicates that pulsed electromagnetic fields (PEMF) could accelerate fracture healing and enhance bone mass, whereas the unclear mechanism by which PEMF stimulation promotes osteogenesis limits its extensive clinical application. In the present study, effects and potential molecular signaling mechanisms of PEMF on in vitro osteoblasts were systematically investigated. Osteoblast-like MC3T3-E1 cells were exposed to PEMF burst (0.5, 1, 2, or 6 h/day) with 15.38 Hz at various intensities (5 Gs (0.5 mT), 10 Gs (1 mT), or 20 Gs (2 mT)) for 3 consecutive days. PEMF stimulation at 20 Gs (2 mT) for 2 h/day exhibited most prominent promotive effects on osteoblastic proliferation via Cell Counting kit-8 analyses. PEMF exposure induced well-organized cytoskeleton, and promoted formation of extracellular matrix mineralization nodules. Significantly increased proliferation-related gene expressions at the proliferation phase were observed after PEMF stimulation, including Ccnd 1 and Ccne 1. PEMF resulted in significantly increased gene and protein expressions of alkaline phosphatase and osteocalcin at the differentiation phase of osteoblasts rather than the proliferation phase via quantitative reverse transcription polymerase chain reaction and Western blotting analyses. Moreover, PEMF upregulated gene and protein expressions of collagen type 1, Runt-related transcription factor 2 and Wnt/ß-catenin signaling (Wnt1, Lrp6, and ß-catenin) at proliferation and differentiation phases. Together, our present findings highlight that PEMF stimulated osteoblastic functions through a Wnt/ß-catenin signaling-associated mechanism and, hence, regulates downstream osteogenesis-associated gene/protein expressions. Bioelectromagnetics. 37:152-162, 2016. © 2016 Wiley Periodicals, Inc.

Gut microbiome and metabolome in aneurysm rat with hypertension after ginsenoside Rb1 treatment.

Introduction: Hypertension is a well-known risk factor for aneurysms, as high blood pressure can worsen the development and rupture of aneurysms. Ginsenoside, derived from ginseng and widely used in traditional herbal medicine, is believed to have antihypertensive properties. Recent research has also shown a connection between gut microbiota and various diseases, including hypertension. However, the relationship between ginsenosides, gut microbiota, blood pressure, and intracranial aneurysms needs further exploration. Methods: In this study, a rat model was used to investigate the effects of ginsenosides on both blood pressure and intracranial arteries. Comparative analysis was conducted, and 16S rRNA sequencing was employed to identify marker genera within the gut microbiota. Metabolites were also analyzed to uncover potential mediators of blood pressure regulation. Results and Discussion: The results of this study revealed that ginsenosides, particularly ginsenoside Rb1, demonstrated positive effects in reducing both blood pressure and the development of intracranial aneurysms in rats. Furthermore, the analysis of gut microbiota showed that certain genera, including Clostridium, Roseburia, Ruminococcus, and Treponema, were significantly influenced by ginsenoside treatment. Several metabolites, such as behenic acid, N-Acetylserotonin, Prostaglandin F2a, and Vitamin D2, were also detected, all of which play a role in regulating blood pressure. These findings provide valuable insights into the potential benefits of ginsenosides in hypertension and atheroma development. Furthermore, they suggest a possible link between ginsenosides, gut microbiota, and blood pressure regulation. Further research is needed to fully understand the mechanisms underlying these effects and to determine the clinical implications for treating hypertension and reducing the risk of aneurysm development.

MicroRNA-3200-3p targeting CAMK2A modulates the proliferation and metastasis of glioma in vitro.

MicroRNA (miRNA) is strongly interrelated with the pathogenesis of glioma. However, its potential biological effect and underlying mechanism of miR-3200-3p in human glioma remain elusive. In the current study, we checked the level of miR-3200-3p in different glioma cells. Then, its biological functions on glioma cell proliferation metastasis was investigated using the miR-3200-3p mimic and inhibitor. The direct target of miR-3200-3p was tested in these cells. Results demonstrated that miR-3200-3p is remarkably downregulated in human glioma cells. The relative level of miR-3200-3p is strongly associated with biological features, including proliferation, colony formation, and metastasis. Additionally, Ca2+/calmodulin dependent kinase 2a (CAMK2A) might be the direct target gene of miR-3200-3p, and CAMK2A overexpression reversed the anticancer roles of miR-3200-3p on glioma cellular function. Importantly, these results further showed that miR-3200-3p downregulated the proliferation and metastasis by suppressing the expression of CAMK2A, thus regulating the Ras/Raf/MEK/ERK pathway. This study provided provided insights into the biological role of miR-3200-3p, which might function as a potential biomarker in glioma therapy.

Biomechanically stimulated chondrocytes promote osteoclastic bone resorption in the mandibular condyle.

OBJECTIVE: Chondrocyte signaling is important in osteoclastic bone resorption in mice tibiae. The present study aimed to test whether biomechanically stimulated chondrocytes promote osteoclastic bone resorption in the mandibular condyle. METHODS: Primary chondrocytes isolated from rat condylar cartilage were stimulated by fluid flow shear stress (FSS) for 30, 60, 120 min at intensities of 10, 20, or 30 dynes/cm2. The levels of pro-osteoclastic factors and pro-osteoclastic function of FSS-stimulated chondrocytes were tested. Abnormal molar occlusion was established in rats, and the relationship between cartilage degeneration and osteoclastogenesis in the subchondral bone of the mandibular condyle, and the expression of pro-osteoclastic factors in condylar cartilage, were evaluated. RESULTS: The mRNA and protein levels of SDF-1 and TGFß-1 increased significantly in all FSS-treated groups; the levels of RANKL and RANKL:OPG increased in all intensities and in 60 and 120 min of FSS; and those of Wnt5 A increased in all time-points and in 20 and 30 dynes/cm2 of FSS-treated groups (all compared with their levels the controls; P < 0.05). The percent area of degenerative cartilage changes correlated positively with osteoclast number and osteoclast surface/bone surface in the mandibular condyles of abnormal occlusion rats (P < 0.05). Abnormal occlusion increased the immune-positive area and the mRNA expression levels of Sdf1, Tgfb1, Rankl, Wnt5a and the RANKL:OPG ratio in rat condylar cartilage compared with those in the controls (all P < 0.05). CONCLUSION: Chondrocytes under mechanical stimulation could express higher levels of pro-osteoclastic factors and induced condylar subchondral bone resorption by promoting osteoclastogenesis.

Hey1 functions as a positive regulator of odontogenic differentiation in odontoblast­lineage cells.

Substantial evidence has indicated that Notch and bone morphogenetic protein (BMP) signaling may regulate odontoblastic differentiation. Hairy/enhancer­of­split related with YRPW motif 1 (Hey1), a downstream target gene of Notch and BMP signaling, is expressed in dental pulp tissues and has been demonstrated to be responsible for osteoblast mineralization. The aim of this study was to investigate the effects of Hey1 on odontoblast differentiation. The results of the study demonstrated that Hey1 expression in odontoblast­lineage cells (OLCs) was upregulated by stimulation of osteoblastic/odontoblastic differentiation medium containing ascorbic acid, ß­glycerol phosphate and dexamethasone. Furthermore, stable Hey1­overexpressing cells expressed higher levels of dentin sialophosphoprotein (DSPP) and exhibited higher mineralization capabilities following stimulation by differentiation medium. Furthermore, RNA interference­mediated knockdown of Hey1 downregulated the expression levels of DSPP in OLCs stimulated by differentiation medium. Taken together, the findings indicate that Hey1 may be a positive regulator of odontoblastic differentiation. The present study broadens the understanding of odontoblast differentiation and biomineralization.

Notch1 signalling inhibits apoptosis of human dental follicle stem cells via both the cytoplasmic mitochondrial pathway and nuclear transcription regulation.

Dental follicle stem cells (DFSCs) have been considered as promising candidate cells for periodontal tissue regeneration. Understanding the signalling pathways underlying the apoptosis of DFSCs will facilitate its biomedical application. Here we showed that Notch1 signalling could inhibit DFSCs apoptosis because the constitutive overexpression of the intracellular domain of Notch1 (ICN1) promoted proliferation and suppressed apoptosis by inhibiting cytoplasmic mitochondrial membrane depolarization, cytochrome c release and activation of caspase-9 and caspase-3. The survival-promoting effect of Notch1 was also accomplished by up-regulation of the anti-apoptotic proteins Bcl-2 and Mcl-1, down-regulation of the pro-apoptotic proteins Bax and Bad, and blockade of Bax multimerization. Moreover, p-Akt (S473) was significantly increased after ectopic Notch 1 activation. The expression of p53 was also inhibited in Notch1-overexpressing DFSCs, while the ectopic expression of p53 promoted apoptosis even when Notch1 was overexpressed. Meanwhile, all of the opposite phenomena were observed in Notch1 shRNA-silenced DFSCs. Our data strongly suggested that Notch1 signalling inhibited the apoptosis of DFSCs via the cytoplasmic mitochondrial pathway and ICN-Akt signalling pathway, together with nuclear gene expression regulation. These findings would provide molecular cues for the further medical application of DFSCs.

Effects of low-intensity pulsed electromagnetic fields on bone microarchitecture, mechanical strength and bone turnover in type 2 diabetic db/db mice.

Type 2 diabetic patients have impaired bone quality, leading to increased fracture risk. Substantial evidence demonstrates that pulsed electromagnetic fields (PEMF) could resist osteopenia/osteoporosis induced by estrogen deficiency and disuse. However, the effects of PEMF on osteopenia/osteoporosis associated with diabetes, especially for more prevalent type 2 diabetes, remain poorly understood. We herein investigated the skeletal effects and mechanisms of PEMF (15 Hz, 20 Gs) on leptin receptor-deficient db/db mice with typical type 2 diabetic symptoms. Our µCT results showed that 12-week PEMF exposure significantly improved both cancellous and cortical bone microarchitecture in db/db mice. Three-point bending and biomechanical indentation testing demonstrated that PEMF improved whole-bone structural properties and tissue-level material properties in db/db mice. PEMF significantly promoted bone formation in db/db mice evidenced by increased serum osteocalcin and bone mineral apposition rate, whereas PEMF exerted no observable alteration in bone resorption. Real-time PCR showed that PEMF upregulated tibial gene expression of osteoblastogenesis-related of canonical Wnt/ß-catenin signaling but not osteoclastogenesis-related RANKL-RANK signaling in db/db mice. Our findings demonstrate that PEMF improved bone quantity and quality with obvious anabolic activities in db/db mice, and imply that PEMF might become a clinically applicable treatment modality for improving bone quality in type 2 diabetic patients.

Cyclic stretch promotes osteogenesis-related gene expression in osteoblast-like cells through a cofilin-associated mechanism.

Osteoblasts have the capacity to perceive and transduce mechanical signals, and thus, regulate the mRNA and protein expression of a variety of genes associated with osteogenesis. Cytoskeletal reconstruction, as one of the earliest perception events for external mechanical stimulation, has previously been demonstrated to be essential for mechanotransduction in bone cells. However, the mechanism by which mechanical signals induce cytoskeletal deformation remains poorly understood. The actin­binding protein, cofilin, promotes the depolymerization of actin and is understood to be important in the regulation of activities in various cell types, including endothelial, neuronal and muscle cells. However, to the best of our knowledge, the importance of cofilin in osteoblastic mechanotransduction has not been previously investigated. In the present study, osteoblast­like MG­63 cells were subjected to physiological cyclic stretch stimulation (12% elongation) for 1, 4, 8, 12 and 24 h, and the expression levels of cofilin and osteogenesis-associated genes were quantified with reverse transcription­quantitative polymerase chain reaction, immunofluorescence staining and western blotting analyses. Additionally, knockdown of cofilin using RNA interference was conducted, and the mRNA levels of osteogenesis­associated genes were compared between osteoblast­like cells in the presence and absence of cofilin gene knockdown. The results of the present study demonstrated that cyclic stretch stimulates the expression of genes associated with osteoblastic activities in MG­63 cells, including alkaline phosphatase (ALP), osteocalcin (OCN), runt­related transcription factor 2 (Runx2) and collagen­1 (COL­1). Cyclic stretch also regulates the mRNA and protein expression of cofilin in MG­63 cells. Furthermore, stretch­induced increases in the levels of osteogenesis-associated genes, including ALP, OCN, Runx2 and COL­1, were reduced following cofilin gene knockdown. Together, these results demonstrate that cofilin is involved in the regulation of mechanical load­induced osteogenesis and, to the best of our knowledge, provides the first evidence demonstrating the importance of cofilin in osteoblastic mechanotransduction.

Cyclic mechanical stretch promotes energy metabolism in osteoblast-like cells through an mTOR signaling-associated mechanism.

Energy metabolism is essential for maintaining function and substance metabolism in osteoblasts. However, the role of cyclic stretch in regulating osteoblastic energy metabolism and the underlying mechanisms remain poorly understood. In this study, we found that cyclic stretch (10% elongation at 0.1 Hz) significantly enhanced glucose consumption, lactate levels (determined using a glucose/lactate assay kit), intracellular adenosine triphosphate (ATP) levels (quantified using rLuciferase/Luciferin reagent) and the mRNA expression of energy metabolism-related enzymes [mitochondrial ATP synthase, L-lactate dehydrogenase A (LDHA) and enolase 1; measured by RT-qPCR], and increased the phosphorylation levels of Akt, mammalian target of rapamycin (mTOR) and p70s6k (measured by western blot analysis) in human osteoblast­like MG­63 cells. Furthermore, the inhibition of Akt or mTOR with an antagonist (wortmannin or rapamycin) suppressed the stretch-induced increase in glucose consumption, lactate levels, intracellular ATP levels and the expression of mitochondrial ATP synthase and LDHA, indicating the significance of the Akt/mTOR/p70s6k pathway in regulating osteoblastic energy metabolism in response to mechanical stretch. Thus, we concluded that cyclic stretch regulates energy metabolism in MG­63 cells partially through the Akt/mTOR/p70s6k signaling pathway. The present findings provide novel insight into osteoblastic mechanobiology from the perspective of energy metabolism.

Cyclic stretch enhances bone morphogenetic protein-2-induced osteoblastic differentiation through the inhibition of Hey1.

Substantial evidence has indicated that osteoblastic differentiation may be regulated by mechanical loads or bone morphogenetic protein-2 (BMP-2). BMP-2-induced in vivo osteogenesis can be significantly enhanced in the presence of mechanical stimuli, revealing the therapeutic potential of the combined application of BMP-2 and mechanical loads in clinical bone diseases (e.g., bone fractures and osteoporosis); however, the underlying mechanisms remain elusive. In this study, we found that cyclic stretch or BMP-2 alone increased the expression of osteoblastic differentiation markers, including alkaline phosphatase (ALP) and runt-related transcription factor 2 (Runx2), as shown by RT-qPCR, western blot analysis and ALP activity test. Furthermore, our results revealed that cyclic mechanical stretch with 10% elongation at 0.1 Hz significantly enhanced the BMP-2-induced upregulation of ALP and Runx2 expression in osteoblast-like MC3T3-E1 cells. Cyclic stretch also inhibited the BMP-2-induced upregulation of Hes-related family bHLH transcription factor with YRPW motif 1 (Hey1, measured by RT-qPCR and immunofluorescence staining), a potent negative regulator of osteogenesis. Moreover, the transient transfection of a Hey1 expression plasmid (pcDNA3.1-Hey1) significantly reversed the effects of cyclic stretch on the BMP-2-induced upregulation of differentiation markers in the MC3T3-E1 cells. This revealed the importance of Hey1 in modulating BMP-2-induced osteoblastic differentiation in response to cyclic stretch. Taken together, our results demonstrated that cyclic stretch enhanced the BMP-2­induced osteoblastic differentiation through the inhibition of Hey1. The present study broadens our fundamental knowledge of osteoblastic mechanotransduction and also sheds new insight into the mechanisms through which the combined application of BMP-2 and mechanical load promotes osteogenesis.

Increases in PKC gamma expression in trigeminal spinal nucleus is associated with orofacial thermal hyperalgesia in streptozotocin-induced diabetic mice.

Painful diabetic polyneuropathy (PDN) at the early phrase of diabetes frequently exhibits increased responsiveness to nociception. In diabetic patients and animal models, alterations in the transmission of orofacial sensory information have been demonstrated in trigeminal system. Herein, we examined the changes of protein kinase Cγ subunit (PKCγ) in trigeminal spinal nucleus (Sp5C) and observed the development of orofacial thermal sensitivity in streptozotocin (STZ)-induced type 1 diabetic mice. With hyperglycemia and body weight loss, STZ mice exhibited orofacial thermal hyperalgesia, along with increased PKCγ expression in Sp5C. Insulin treatment at the early stage of diabetes could alleviate the orofacial thermal hyperalgesia and impaired increased PKCγ in Sp5C in diabetic mice. In summary, our results demonstrate that PKCγ might be involved in orofacial thermal hyperalgesia of diabetes, and early insulin treatment might be effective way to treat orofacial PDN.