A rare case of multiple brain abscesses caused by apical periodontitis of deciduous teeth in congenital heart disease: a case report.

BACKGROUND: A brain abscess is a focal infection in which abscesses form in the brain. A brain abscess is a rare but fatal disease when rupture occurs into the ventricles. We report a case of multiple brain abscesses caused by a hematogenous infection from the apical periodontitis of deciduous teeth. CASE PRESENTATION: The patient was a 7-years and 8-months-old male with congenital heart disease. The patient sought medical attention due to fever and headache, for which he was started on three antibiotics with a diagnosis of multiple brain abscesses. Given that apical periodontitis of deciduous teeth was strongly suspected as the source of the brain abscess, the deciduous teeth were extracted. Immediately after deciduous teeth extraction, the patient's headache and neurological symptoms disappeared. CONCLUSIONS: After teeth extraction, a clear shrinkage of the brain abscess was observed, and the patient was discharged from the hospital.

Differential regulation of medium spiny and cholinergic neurons in the nucleus accumbens core by the insular and medial prefrontal cortices in the rat.

The nucleus accumbens (NAc) receives cortical projections principally from the insular cortex (IC) and medial prefrontal cortex (mPFC). Among NAc neurons, cholinergic interneurons (ChNs) regulate the activities of medium spiny neurons (MSNs), which make up ~ 95% of NAc neurons, by modulating their firing and synaptic properties. However, little is known about the synaptic mechanisms, including their cell-type-dependent corticoaccumbal projection properties and cholinergic effects on the NAc core. Here, we performed whole-cell patch-clamp recordings from NAc MSNs and ChNs in acute brain slice preparations obtained from rats that received an AAV5-hSyn-ChR2(H134R)-mCherry injection into the IC or mPFC. Light stimulation of IC or mPFC axons induced comparable phase-locked excitatory postsynaptic currents (EPSCs) in MSNs. On the other hand, ChNs showed consistent EPSCs evoked by light stimulation of mPFC axons, whereas light stimulation of IC axons evoked much smaller EPSCs, which often showed failure in ChNs. Light-evoked EPSCs were abolished by tetrodotoxin and were recovered by 4-aminopyridine, suggesting that corticoaccumbal projections monosynaptically induce EPSCs in MSNs and ChNs. Carbachol effectively suppressed the amplitude of EPSCs in MSNs and ChNs evoked by light stimulation of IC or mPFC axons and in ChNs evoked by stimulating mPFC axons. The carbachol-induced suppression was recovered by atropine or pirenzepine, while preapplication of gallamine, J104129, PD102807, or AF-DX384 did not block the carbachol-induced EPSC suppression. These results suggest that NAc MSNs and ChNs are differentially regulated by excitatory projections from the IC and mPFC and that these corticoaccumbal excitatory inputs are modulated by M1 receptor activation.

Early Postnatal Treatment with Valproate Induces Gad1 Promoter Remodeling in the Brain and Reduces Apnea Episodes in Mecp2-Null Mice.

The deletion of Mecp2, the gene encoding methyl-CpG-binding protein 2, causes severe breathing defects and developmental anomalies in mammals. In Mecp2-null mice, impaired GABAergic neurotransmission is demonstrated at the early stage of life. GABAergic dysfunction in neurons in the rostral ventrolateral medulla (RVLM) is considered as a primary cause of breathing abnormality in Mecp2-null mice, but its molecular mechanism is unclear. Here, we report that mRNA expression levels of Gad1, which encodes glutamate decarboxylase 67 (GAD67), in the RVLM of Mecp2-null (Mecp2-/y, B6.129P2(C)-Mecp2tm1.1Bird/J) mice is closely related to the methylation status of its promoter, and valproate (VPA) can upregulate transcription from Gad1 through epigenetic mechanisms. The administration of VPA (300 mg/kg/day) together with L-carnitine (30 mg/kg/day) from day 8 to day 14 after birth increased Gad1 mRNA expression in the RVLM and reduced apnea counts in Mecp2-/y mice on postnatal day 15. Cytosine methylation levels in the Gad1 promoter were higher in the RVLM of Mecp2-/y mice compared to wild-type mice born to C57BL/6J females, while VPA treatment decreased the methylation levels in Mecp2-/y mice. Chromatin immunoprecipitation assay revealed that the VPA treatment reduced the binding of methyl-CpG binding domain protein 1 (MBD1) to the Gad1 promoter in Mecp2-/y mice. These results suggest that VPA improves breathing of Mecp2-/y mice by reducing the Gad1 promoter methylation, which potentially leads to the enhancement of GABAergic neurotransmission in the RVLM.

Opposing role of NMDA receptor GluN2B and GluN2D in somatosensory development and maturation.

Development of correct topographical connections between peripheral receptors and central somatosensory stations requires activity-dependent synapse refinement, in which the NMDA type of glutamate receptors plays a key role. Here we compared functional roles of GluN2B (GluRε2 or NR2B) and GluN2D (GluRε4 or NR2D), two major regulatory subunits of neonatal NMDA receptors, in development of whisker-related patterning at trigeminal relay stations. Compared with control littermates, both the appearance of whisker-related patterning and the termination of the critical period, as assessed by unilateral infraorbital nerve transection, were delayed by nearly a day in the somatosensory cortex of GluN2B(+/-) mice but advanced by nearly a day in GluN2D(-/-) mice. Similar temporal shifts were found at subcortical relay stations in the thalamus and brainstem of GluN2B(+/-) and GluN2D(-/-) mice. In comparison, the magnitude of lesion-induced critical period plasticity in the somatosensory cortex, as assessed following row-C whisker removal, was normal in both mutants. Thus, GluN2B and GluN2D play counteractive roles in temporal development and maturation of somatosensory maps without affecting the magnitude of critical period plasticity. To understand the opposing action, we then examined neuronal and synaptic expressions of the two subunits along the trigeminal pathway. At each trigeminal station, GluN2B was predominant at asymmetrical synapses of non-GABAergic neurons, whereas GluN2D was selective to asymmetrical synapses of GABAergic neurons. Together, our findings suggest that GluN2B expressed at glutamatergic synapses on glutamatergic projection neurons facilitates refinement of ascending pathway synapses directly, whereas GluN2D expressed at glutamatergic synapses on GABAergic interneurons delays it indirectly.

Simultaneous activation of the α1A-, α1B- and α1D-adrenoceptor subtypes in the nucleus accumbens reduces accumbal dopamine efflux in freely moving rats.

Intra-accumbal infusion of the α1-adrenergic agonist methoxamine, which has comparable affinity for α1A-, α1B- and α1D-adrenoceptor subtypes, fails to alter noradrenaline efflux but reduces dopamine efflux in the nucleus accumbens of rats. In-vivo microdialysis experiments were carried out to analyse the putative contribution of α1A-, α1B- and α1D-adrenoceptor subtypes to the methoxamine-induced decrease in accumbal dopamine efflux in freely moving rats. The drugs used were dissolved in the infusion medium and administered locally through a dialysis membrane. Intra-accumbal infusions of the α1A-adrenoceptor antagonist 5-methylurapidil (6 pmol), the α1B-adrenoceptor antagonist cyclazosin (0.6 and 6 pmol) and the α1D-adrenoceptor antagonist BMY 7378 (0.6 pmol) did not alter accumbal efflux of noradrenaline or dopamine: pretreatment with each of these α1-adrenoceptor subtype-selective antagonists counteracted the methoxamine (24 pmol)-induced decrease in accumbal dopamine efflux. Doses indicated are the total amount of drug administered over a 60-min infusion period. These results clearly suggest that the α1A-, α1B- and α1D-adrenoceptor subtypes in the nucleus accumbens mediate the α1-adrenergic agonist methoxamine-induced decrease in accumbal dopamine efflux. The present study also provides in-vivo neurochemical evidence indicating that concomitant, but not separate, activation of the α1A-, α1B- and α1D-adrenoceptors in the nucleus accumbens is required for α1-adrenergic inhibition of accumbal dopaminergic activity.

Alteration of monoaminergic systems in the caudal medulla and its possible link to diurnal increase of apnea in a mouse model of Rett syndrome.

PURPOSE: Methyl-CpG binding protein 2 (MeCP2)-deficient (Mecp2-/y) mice exhibit apneas that resemble respiratory abnormalities observed in Rett syndrome (RTT) patients. The present study aimed to clarify whether Mecp2-/y mice show diurnal variations in apnea as seen in RTT and how the MeCP2 deficiency affects monoaminergic systems that control breathing. METHODS: In 7-week-old Mecp2-/y mice, 24 h variation of apnea and effects of milnacipran, a serotonin/noradrenaline reuptake inhibitor, on the apnea were evaluated. The number of vesicular monoamine transporter 2 (VMAT2)-immunoreactive puncta in the caudal medulla was counted. Further, the effects of valproate (VPA) on the expression of tyrosine hydroxylase (TH) mRNA in the ventrolateral medulla of mice were assessed by RT-qPCR. RESULTS: Apnea occurred more frequently during the light phase under a 12:12 h light/dark environment in Mecp2-/y mice and milnacipran reduced apnea during the light phase but not during the dark phase. The number of VMAT2-immunoreactive puncta was reduced in Mecp2-/y mice. VPA treatment significantly increased TH mRNA expression in Mecp2-/y mice. CONCLUSION: Alteration of monoaminergic systems in the caudal medulla of Mecp2-/y mice is potentially relevant to the light-sensitive diurnal increase of apnea, and an improvement in monoaminergic neurotransmission can ameliorate the diurnal increase of apnea in Mecp2-/y mice.

Involvement of oxidative stress in orofacial mechanical pain hypersensitivity following neonatal maternal separation in rats.

Patients with persistent pain have sometimes history of physical abuse or neglect during infancy. However, the pathogenic mechanisms underlying orofacial pain hypersensitivity associated with early-life stress remain unclear. The present study focused on oxidative stress and investigated its role in pain hypersensitivity in adulthood following early-life stress. To establish an early-life stress model, neonatal pups were separated with their mother in isolated cages for 2 weeks. The mechanical head-withdrawal threshold (MHWT) in the whisker pad skin of rats received maternal separation (MS) was lower than that of non-MS rats at postnatal week 7. In MS rats, the expression of 8-hydroxy-deoxyguanosine, a marker of DNA oxidative damage, was enhanced, and plasma antioxidant capacity, but not mitochondrial complex I activity, decreased compared with that in non-MS rats. Reactive oxygen species (ROS) inactivation and ROS-sensitive transient receptor potential ankyrin 1 (TRPA1) antagonism in the whisker pad skin at week 7 suppressed the decrease of MHWT. Corticosterone levels on day 14 increased in MS rats. Corticosterone receptor antagonism during MS periods suppressed the reduction in antioxidant capacity and MHWT. The findings suggest that early-life stress potentially induces orofacial mechanical pain hypersensitivity via peripheral nociceptor TRPA1 hyperactivation induced by oxidative stress in the orofacial region.

Neonatal Injury Modulates Incisional Pain Sensitivity in Adulthood: An Animal Study.

Neonatal pain experiences including traumatic injury influence negatively on development of nociceptive circuits, resulting in persistent pain hypersensitivity in adults. However, the detailed mechanism is not yet well understood. In the present study, to clarify the pathogenesis of orofacial pain hypersensitivity associated with neonatal injury, the involvement of the voltage-gated sodium channel (Nav) 1.8 and the C-C chemokine ligand 2 (CCL2)/C-C chemokine receptor 2 (CCR2) signaling in the trigeminal ganglion (TG) in facial skin incisional pain hypersensitivity was examined in 190 neonatal facial-injured and sham male rats. The whisker pad skin was incised on postnatal day 4 and week 7 (Incision-Incision group). Compared to the group without neonatal incision (Sham-Incision group), mechanical hypersensitivity in the whisker pad skin was enhanced in Incision-Incision group. The number of Nav1.8-immunoreactive TG neurons and the amount of CCL2 expressed in the macrophages and satellite glial cells in the TG were increased on day 14 after re-incision in the Incision-Incision group, compared with Sham-Incision group. Blockages of Nav1.8 in the incised region and CCR2 in the TG suppressed the enhancement of mechanical hypersensitivity in the Incision-Incision group. Administration of CCL2 into the TG enhanced mechanical hypersensitivity in the Sham-Sham, Incision-Sham and Sham-Incision group. Our results suggest that neonatal facial injury accelerates the TG neuronal hyperexcitability following orofacial skin injury in adult in association with Nav1.8 overexpression via CCL2 signaling, resulting in the enhancement of orofacial incisional pain hypersensitivity in the adulthood.

Bone resorption improvement by conditioned medium of stem cells from human exfoliated deciduous teeth in ovariectomized mice.

Stem cells from human exfoliated deciduous teeth (SHED) are mesenchymal stem cells with multipotent differentiation potential present in the dental pulp tissue of the deciduous teeth. SHED produce secretions that have immunomodulatory and regenerative functions. In the present study, we investigated the effects of SHED-conditioned medium (SHED-CM) on osteopenia induced by the ovariectomy (OVX) phenotype and its corresponding immunological changes. Eleven-week-old female C3H/HeJ mice were subjected to OVX. SHED-CM was administered intraperitoneally in these mice for 4 weeks starting immediately after OVX. SHED-CM improved bone mass after OVX and elevated the polarization of M2 macrophages in the peritoneal cavity. SHED-CM also suppressed an OVX-induced increase in interferon-γ (INF-γ) and interleukin-17 (IL-17) concentrations in the peripheral blood. Inhibition of M2 macrophage polarization with neutralizing antibodies did not reduce the concentration of IFN-γ and IL-17 in peripheral blood, which were increased by OVX, and did not alleviate osteopenia induced by the OVX phenotype. Mechanistically, these findings suggest that SHED-CM alleviates bone resorption by suppressing the activation of IFN-γ and IL-17 cells by polarizing M2 macrophages. In conclusion, our data indicate that SHED-CM contains active secretions that may have promising efficacy to ameliorate OVX-induced osteopenia. We suggest that SHED-CM has the potential to be used as a novel therapeutic agent to inhibit osteoporosis.

Anti-RANKL Inhibits Thymic Function and Causes DRONJ in Mice.

Background: Denosumab, a human monoclonal antibody against receptor activator of nuclear factor-kappa B ligand (RANKL), is a novel bone antiresorptive agent used in patients with osteoporosis or metastatic bone cancer. Denosumab-related osteonecrosis of the jaw (DRONJ) has been recently reported in patients using denosumab. However, the mechanisms of DRONJ are not fully understood. Appropriate pathogenic mechanisms of DRONJ have yet to be established. Therefore, we investigated the pathogenesis of DRONJ in mice. Methods: Anti-mouse RANKL monoclonal antibody and melphalan were performed to create a mouse model of DRONJ-like lesions in female C57BL/6J mice. We examined the development of DRONJ-like lesions and immune function. Results: We showed that administration of anti-mouse RANKL monoclonal antibody and melphalan caused DRONJ-like lesions that recapitulated major clinical manifestations of the human disease, including the characteristic features of an open alveolar socket and exposed necrotic bone. In the analysis using a mouse model of DRONJ-like lesion, it was revealed that anti-mouse RANKL monoclonal antibody and melphalan suppress autoimmune regulator (AIRE) expression in the thymus and imbalanced T cell populations. Conclusion: This study suggests evidence of an immunity-based mechanism of DRONJ-like disease. This work may contribute to a better understanding of the pathogenesis of human DRONJ.

Decreased PPARgamma in the trigeminal spinal subnucleus caudalis due to neonatal injury contributes to incision-induced mechanical allodynia in female rats.

Whisker pad skin incision in infancy causes the prolongation of mechanical allodynia after re-incision in adulthood. A recent study also proposed the importance of sex differences in pain signaling in the spinal cord. However, the sex difference in re-incision-induced mechanical allodynia in the orofacial region is not fully understood. In the rats that experienced neonatal injury in the whisker pad skin, the mechanical allodynia in the whisker pad was significantly prolonged after re-incision in adulthood compared to sham injury in infancy. No significant sex differences were observed in the duration of mechanical allodynia. The duration of mechanical allodynia in male rats was shortened by intracisternal administration of minocycline. However, minocycline had no effects on the duration of mechanical allodynia in female rats. In contrast, intracisternal administration of pioglitazone markedly suppressed mechanical allodynia in female rats after re-incision. Following re-incision, the number of peroxisome proliferator-activated receptor gamma (PPARgamma)-positive cells were reduced in the trigeminal spinal subnucleus caudalis (Vc) in female rats that experienced neonatal injury. Immunohistochemical analyses revealed that PPARgamma was predominantly expressed in Vc neurons. Pioglitazone increased the number of PPARgamma-positive Vc neurons in female rats whose whisker pad skin was incised in both infancy and adulthood stages. Pioglitazone also upregulated heme oxygenase 1 and downregulated NR1 subunit in the Vc in female rats after re-incision. Together, PPARgamma signaling in Vc neurons is a female-specific pathway for whisker pad skin incision-induced mechanical allodynia.

In vivo monitoring of circadian timing in freely moving mice.

In mammals, the principal circadian pacemaker driving daily physiology and behavioral rhythms is located in the suprachiasmatic nucleus (SCN) in the anterior hypothalamus. The neural output of SCN is essential for the circadian regulation of behavioral activity. Although remarkable progress has been made in revealing the molecular basis of circadian rhythm generation within the SCN, the output pathways by which the SCN exert control over circadian rhythms are not well understood. Most SCN efferents target the subparaventricular zone (SPZ), which resides just dorsal to the SCN. This output pathway has been proposed as a major component involved in the outflow for circadian regulation. We have examined the downstream pathway of the central clock by means of multiunit neural activity (MUA) in freely moving mice. SCN neural activity is tightly coupled to environmental photic input and anticorrelated with MUA rhythm in the SPZ. In Clock mutant mice exhibiting attenuated circadian locomotor rhythmicity, MUA rhythmicity in the SCN and SPZ is similarly blunted. These results suggest that the SPZ plays a functional role in relaying circadian and photic signals to centers involved in generating behavioral activity.

Presynaptic NK1 Receptor Activation by Substance P Suppresses EPSCs via Nitric Oxide Synthesis in the Rat Insular Cortex.

Substance P (SP) regulates inhibitory synaptic transmission mediated by GABAA receptors in the cerebral cortex; however, SP-mediated regulation of excitatory synaptic transmission remains poorly understood. We performed whole-cell patch-clamp recordings from pyramidal neurons to examine the effects of SP on excitatory postsynaptic currents (EPSCs) mediated via AMPA receptors in the insular cortex (IC), which is involved in nociceptive information processing. First, EPSCs evoked by minimal electrical stimulation (eEPSCs) including stepwise EPSCs and failure events, were examined. SP dose-dependently suppressed mean eEPSC amplitude, partially due to an increase in the failure rate of eEPSCs. The SP-induced suppression of eEPSCs was accompanied by an increase in the paired-pulse ratio and was inhibited by the preapplication of SR140333, an NK1 receptor antagonist. [Sar9,Met(O2)11]-substance P, an NK1 receptor-selective agonist, mimicked the effects of SP on eEPSCs and decreased the frequency of miniature EPSCs (mEPSCs) without changing the average mEPSC amplitude. Considering that most NK1 receptors in the cerebral cortex are expressed in nitric oxide synthase (NOS)-positive GABAergic neurons, the SP-induced suppressive effect on EPSCs may be mediated by nitric oxide (NO) in this subtype of GABAergic neurons. NO imaging using the fluorescent probe DAX-J2 Red supports this hypothesis: SP increased the fluorescence intensity of DAX-J2 Red in some GABAergic neurons. Furthermore, both L-NAME, an NOS inhibitor, and PTIO, an NO scavenger, diminished the SP-induced suppression of eEPSCs. These results suggest that the activation of presynaptic NK1 receptors contributes to SP-induced eEPSC suppression by activating the NO synthesis pathway in GABAergic neurons. (246 words).

Microglial activation in the trigeminal spinal subnucleus interpolaris/caudalis modulates orofacial incisional mechanical pain hypersensitivity associated with orofacial injury in infancy.

PURPOSE: Infantile tissue injury induces sensory deficits in adulthood. Infantile facial incision (IFI) was reported to cause an enhancement of incision-induced mechanical hypersensitivity in adulthood due to acceleration of the trigeminal ganglion neuronal excitability. However, the effects of IFI on activation of microglia in the spinal trigeminal nucleus and its involvement in facial pain sensitivity is not well known. METHODS: A facial skin incision was made in the left whisker pad in infant (IFI) and/or adult rats (AFI). Mechanical head withdrawal threshold and microglial activation in the trigeminal spinal nucleus were analyzed. RESULTS: Mechanical pain hypersensitivity induced by AFI was significantly exacerbated and prolonged by IFI. The number of Iba1-immunoreactive cells in the trigeminal spinal nucleus following AFI was increased by IFI, suggesting that IFI facilitates microglial hyperactivation following AFI. Intraperitoneal administration of minocycline, a microglial activation inhibitor, suppressed the facial incision-induced microglial hyperactivation in the trigeminal spinal nucleus and the exacerbation of the facial mechanical pain hypersensitivity induced by IFI. CONCLUSION: These results suggest that facial trauma in infants causes hyperactivation of microglia in the trigeminal spinal nucleus following AFI, leading to the prolongation of the facial mechanical pain hypersensitivity.

Oral hygiene and oral status of institutionalized children with motor and intellectual disabilities.

The oral hygiene and oral status of children with severe disabilities with both nutritional and respiratory complications who were institutionalized at Karugamonoie (KNI), a facility for children with disabilities, were investigated in this study. Their oral hygiene management was solely dependent on caregivers and nurses at the institution. Thirty children (13 females, 17 males; average age, 7.6 years) who had a tracheotomy and feeding tube (gastrostomy, nasogastric, or jejunostomy feeding tube) were included in the study. As for oral characteristics, poor control of tongue movement, anterior open-bite, abnormal strain of facial muscles, dry mouth, and swallowing dysfunction were found in 63.3%, 63.3%, 13.3%, 20.0%, and 100.0%, of the children, respectively. The mean ± standard deviation Decayed, Missing, Filled Teeth score was 0.13 ± 0.57. The Gingival Index (GI) showed that the children had mild (53.3%) to moderate (46.7%) gingivitis. The Simplified Oral Hygiene Index was excellent in 50.0% of the children, good in 23.3%, fair in 20.0%, and poor in 6.7% of the children. These indices were satisfactory in general except for GI management, which may have been hampered by abnormal oral functions and anterior open-bite. In conclusion, oral hygiene management of children with nutritional and respiratory complications at KNI was shown to be of high quality even without on-site intervention by dental specialists.

Glutamate transporters regulate lesion-induced plasticity in the developing somatosensory cortex.

Glutamate transporters are involved in neural differentiation, neuronal survival, and synaptic transmission. In the present study, we examined glutamate transporter 1 (GLT1) expression in the neonatal somatosensory cortex of C57BL/6 mice, and pursued its role in somatosensory development by comparing barrel development between GLT1 knock-out and control mice. During the first few neonatal days, a critical period for barrels, GLT1 expression is strikingly upregulated in cortical astrocytes, whereas it was downregulated in neuronal elements to below the detection threshold. GLT1 knock-out neonates developed normally in terms of body growth, cortical histoarchitecture, barrel formation, and critical period termination. However, when row C whiskers were lesioned during the critical period, reduction of lesioned row C barrels and reciprocal expansion of intact row B/D barrels were both milder in GLT1 knock-out mice than in control littermates. Accordingly, the map plasticity index, calculated as (B + D)/2C, was significantly lowered in GLT1 knock-out mice. We also found that extracellular glutamate levels in the neonatal somatosensory cortex were significantly elevated in GLT1 knock-out mice. Diminished lesion-induced plasticity was further found in mutant mice lacking glutamate-aspartate transporter (GLAST), an astrocyte-specific glutamate transporter throughout development. Therefore, glutamate transporters regulate critical period plasticity by enhancing expansion of active barrels and shrinkage of inactive barrels. Because cortical contents of glutamate receptors and GLAST were unaltered in GLT1 knock-out mice, this action appears to be mediated, at least partly, by keeping the ambient glutamate level low. Considering an essential role of glutamate receptors in the formation of whisker-related thalamocortical synapse patterning, glutamate transporters thus facilitate their activity-dependent remodeling.

Clock mutation lengthens the circadian period without damping rhythms in individual SCN neurons.

Spontaneous discharges of individual neurons in the suprachiasmatic nucleus (SCN) of Clock mutant mice were recorded for over 5 days in organotypic slice cultures and dispersed cell cultures using a multi-electrode dish. Circadian rhythms with periods of about 27 hours were detected in 77% of slice cultures and 15% of dispersed cell cultures derived from Clock/Clock homozygotes. These findings indicate that the Clock mutation lengthens the circadian period but does not abolish the circadian oscillation, and suggest an important role of intercellular communication in the expression of circadian rhythm in the SCN.

Hypoxia-induced upregulation of angiogenic factors in immortalized human periodontal ligament fibroblasts.

Hypoxia induces complex cellular responses that are mediated by a key transcription factor, hypoxia-inducible factor-1 (HIF-1). HIF-1 promotes production of cytokines and angiogenic factors and contributes to recovery of injured tissues. In the present study, expressions of angiogenin (ANG) and vascular endothelial growth factor (VEGF), which are potent angiogenic factors in mammalian tissues, were examined in immortalized fibroblasts exposed to hypoxia. After 24 h of exposure to hypoxia, ANG and VEGF mRNAs expressions were significantly elevated in periodontal ligament (PDL) fibroblasts but not in embryonic fibroblasts. Hypoxia also increased productions of ANG and VEGF proteins in PDL fibroblasts. HIF-1α mRNA expression was not affected by hypoxia in either fibroblast, although HIF-1α protein expression was enhanced after exposure to hypoxia. Treatment of PDL fibroblasts with dimethyloxaloylglycine, a prolyl hydroxylase inhibitor that stabilizes the HIF-1α protein, significantly increased expressions of ANG and VEGF mRNAs under normoxia. This suggests that stabilization of HIF-1α is crucial for upregulation of ANG and VEGF in PDL fibroblasts. These results indicate that, under hypoxic conditions, HIF-1α upregulates synthesis of ANG and VEGF in PDL fibroblasts and promotes angiogenesis.

Effect of hypoxia on the expression of CCAAT/enhancer-binding protein ß and receptor activator of nuclear factor kappa-B ligand in periodontal ligament cells.

Hypoxia after traumatic injuries to a tooth is one of the causes of subsequent root resorption. Inflammatory cytokines produced under hypoxic conditions are associated with root resorption, but the mechanism has not been fully understood. In this study, the role of hypoxia-inducible factor-1 (HIF-1) signaling in the regulation of CCAAT (cytosine-cytosine-adenosine-adenosine-thymidine)/enhancer-binding protein-ß (C/EBPß) and the receptor activator of nuclear factor kappa-B ligand (RANKL) expressions in immortalized human periodontal ligament (PDL) cells was investigated. PDL cells cultured under a hypoxic condition showed an increase in the expression of C/EBPß and RANKL messenger RNAs (mRNAs), whereas the expression of osteoprotegerin and HIF-1α mRNAs was unaffected. Hypoxia had no effects on the secretion of interleukin (IL)-1ß, IL-6, IL-8, IL-17A, tumor necrosis factor-alpha, macrophage migration inhibitory factor, monocyte chemoattractant protein-1, and macrophage colony-stimulating factor in the culture media. Treatment of the cells with dimethyloxaloylglycine, a competitive HIF prolyl hydroxylase inhibitor, significantly increased the expression of C/EBPß and RANKL mRNAs. This suggested that the hypoxia-induced elevation of C/EBPß and RANKL mRNAs was dependent on the HIF-1 activity. PDL cells transfected with a specific small interfering RNA designed to target the C/EBPß gene showed a significant suppression of the RANKL mRNA. These findings indicated that C/EBPß may play an important role in tooth root resorption via RANKL activation in hypoxia-exposed PDL cells.

Surgical treatment for sleep apnea: changes in craniofacial and pharyngeal airway morphology in a child with achondroplasia.

Here, we report the case of a male child with achondroplasia who was diagnosed with obstructive sleep apnea and underwent adenoidectomy and tonsillectomy. By analyzing lateral cephalograms, we evaluated the craniofacial and pharyngeal airway morphology immediately before surgery (age, 5 years 6 months) and 1 year 2 months after surgery (age, 6 years 8 months). Adenoidectomy and tonsillectomy dilated the pharynx and improved the craniofacial and pharyngeal morphologies, apparently thus improving the sleep apnea.