Reduced Autophagy in Aged Trigeminal Neurons Causes Amyloid β Diffusion

The relationship between oral health and the development of Alzheimer's disease (AD) in the elderly is not yet well understood. In this regard, the association between aging or neurodegeneration of the trigeminal nervous system and the accumulation of amyloid-β(1-42) (Aβ₄₂) oligomers in the pathogenesis of AD is unknown. We focused on selective autophagy in the trigeminal mesencephalic nucleus (Vmes) and the diffusion of Aβ₄₂ oligomers with respect to aging of the trigeminal nervous system and whether the degeneration of Vmes neurons affects the diffusion of Aβ₄₂ oligomers. We used female 2- to 8-mo-old transgenic 3xTg-AD mice and App^NL-G-F knock-in mice and immunohistochemically examined aging-related changes in selective autophagy and Aβ₄₂ oligomer processing in the Vmes, which exhibits high amyloid-β (Aβ) expression. We induced degeneration of Vmes neurons by extracting the maxillary molars and examined the changes in Aβ₄₂ oligomer kinetics. Autophagosome-like membranes, which stained positive for Aβ, HO-1, and LC3B, were observed in Vmes neurons of 3xTg-AD mice, while there was weak immunoreactivity of the membranes for intraneuronal Aβ in App^NL-G-F mice. By contrast, there was strong immunopositivity for extracellular Aβ₄₂ oligomers with the formation of Aβ₄₂ oligomer clusters in App^NL-G-F mice. The expression of Rubicon, which indicates age-related deterioration of autophagy, increased the diffusion of Aβ₄₂ oligomer with the age of Vmes neurons. Tooth extraction increased the extracellular immunopositivity for Aβ₄₂ oligomers in App^NL-G-F mice. These results suggest that autophagy maintains homeostasis in Vmes neurons and that deterioration of autophagy due to aging or neurodegeneration leads to the diffusion of Aβ₄₂ oligomers into the extracellular space and possibly the development of AD.

P224 Valvuloplasty treatment and three-dimensional analysis for isolated cleft of the anterior mitral valve leaflet: a case report

Introduction: Isolated cleft of the anterior mitral valve leaflet is a very rare congenital disease and a cause of mitral regurgitation

not associated with atrioventricular septal defect. In this case, we report our experience in valvuloplasty treatment for mitral regurgitation with this rare aetiology.

Case description

23-year-old Russian women. Although cardiac murmur was pointed out in her childhood and she was diagnosed as mitral regurgitation, she refused treatment. After getting married with a Japanese man and moving to Japan, her symptoms had worsened and she visited our hospital for treatment. Preoperative transthoracic echocardiography (TTE) had indicated the regurgitation from the central part of the mitral valve. Preoperative transoesophageal echocardiography (TOE) had pointed out the isolated cleft of the anterior mitral valve.

Surgical mitral valvuloplasty was scheduled, and the TOE after anaesthetic induction showed the isolated cleft of the anterior mitral valve the same as in the preoperative period and pointed out the posterior leaflet billowing. The operative finding was also similar to TOE: the largely bisected central anterior mitral valve and billowing, P2 billowing, shortening of P1 and P3, P2-3 cleft. There were no chords at the anterior cleft. The valvuloplasty was performed including five-time pump runs in total: 1) Continuous suture for the anterior cleft and ring annuloplasty were performed, and the regurgitation was seemed to be almost controlled at the water-leak test and the ink test; 2) Artificial chordae and leaflet plications were added to residual regurgitation from the posterior region; 3)The residual regurgitation was controlled to Mild but it became a lateral jet toward the ring; 4)Mild remnant flow was pointed out: the regurgitation seemed to be from the posterior cleft, where immediately below the ring suture; 5) Pericardium patch was added and the remnant flow was almost eliminated. The pump was weaned and the operation was finished without any problems.

Discussion

The cause of difficulty in this valvuloplasty was thought to be caused by the difficulty in evaluating the mitral valve morphology. It was evident that the anterior leaflet of the mitral valve was largely bisected. However, it was difficult to evaluate the coaptation line and area due to the absence of chordal cords in the anterior cleft and the billowing or shortening of the posterior leaflet. Although preoperative three-dimensional analysis helped evaluating the isolated cleft and the regurgitation was almost controlled in the evaluation in the operation field, nevertheless, a residual regurgitation occurred and indicated in the TOE after re-beating.

Conclusion

It is important and necessary to use fine evaluation of coaptation is needed in valvuloplasty for isolated cleft of the anterior mitral valve leaflet; not only apply three-dimensional analysis but also apply two-dimensional echocardiogram.

Abstract P224 Figure.

Safer Vitrification of Mouse and Human Embryos Using the Novel Cryoroom Vitrification System for Assisted Reproductive Technology

BACKGROUND

Vitrification is widely used for assisted reproductive technology (ART). Most vitrification devices require the skillful placement of embryos into the carrier and aspiration of excessive vitrification solution.

OBJECTIVE

To evaluate the efficacy and safety of the Cryoroom as a vitrification device.

MATERIALS AND METHODS

Mouse and human embryos were vitrified with Cryoroom or Cryotop, and the developmental potency was assessed in vitro. Mouse monozygotic twin blastocysts were vitrified with Cryoroom or Cryotop for microarray analysis.

RESULTS AND DISCUSSION

In mouse and human embryos, there were no differences between the survival and developmental progress in each device. In silico, the Cryoroom device showed no changes, particularly in DNA methylation after vitrification compared with the Cryotop. These results showed that the form and function of the device may affect the gene expression levels in vitrified embryos.

CONCLUSION

The Cryoroom represents a safe and potentially revolutionary vitrification device for ART.

Long-term oral bisphosphonates delay healing after tooth extraction: a single institutional prospective study

Tooth extraction in patients receiving bisphosphonates is thought to be a risk factor for osteonecrosis of the jaw (ONJ); however, ONJ did not develop, even when tooth extraction was performed with continued oral bisphosphonate therapy. A drug holiday from bisphosphonates before tooth extraction may not be necessary.

INTRODUCTION

It is controversial whether bisphosphonate withdrawal is necessary prior to invasive procedures such as tooth extraction in order to prevent bisphosphonate-related osteonecrosis of the jaw (BRONJ). This study aimed to evaluate the clinical safety of continuing oral bisphosphonate therapy in patients undergoing tooth extraction.

METHODS

We prospectively enrolled 132 patients (20 men, 112 women) who were receiving oral bisphosphonates for the prevention or treatment of osteoporosis and required tooth extraction. All patients were managed using an identical protocol, which included preoperative antibiotic prophylaxis and did not necessarily require complete wound closure. The patients were classified into groups according to the duration of bisphosphonate administration: < 2 years (n = 51), 2-5 years (n = 41), 5-10 years (n = 28), and > 10 years (n = 12). The groups were compared regarding the time taken for the extraction socket to heal, and the occurrence of BRONJ. Follow-up duration was at least 3 months.

RESULTS

A total of 274 teeth were removed. Long-term oral bisphosphonate therapy for > 5 years significantly delayed the healing of the extraction socket in comparison with administration for < 5 years; however, BRONJ did not develop in any group. There was no prolongation of wound healing due to systemic risk factors such as glucocorticoid administration and diabetes mellitus. There were no adverse skeletal events such as bone fracture.

CONCLUSIONS

Patients who underwent tooth extraction with continued oral bisphosphonate therapy showed delayed healing of the extraction socket as the cumulative administration period prolonged, but BRONJ did not develop.

Synthesis and properties of [7]helicene and [7]helicene-like compounds with a cyclopenta[1,2-b:4,3-b′]dithiophene or dithieno[2,3-b:3′,2′-d]heterole skeleton

A series of [7]helicene and [7]helicene-like compounds composed of a cyclopenta[1,2-b:4,3-b′]dithiophene or dithieno[2,3-b:3′,2′-d]heterole moiety and two naphthalene moieties were successfully synthesized from a common synthetic intermediate, 1,1′-binaphtho[2,1-b]thiophene.

Receptor clustering and activation by multivalent interaction through recognition peptides presented on exosomes

We demonstrate a novel system for inducing clustering of cell surface receptors via recognition peptide segments displayed on exosomes, leading to receptor activation. With this system, targeting of receptor-expressing cells and facilitation of the endocytic uptake of exosomes, which contained the anti-cancer protein saporin, were successfully achieved, leading to cell death.

Assessing the progression of chronic periodontitis using subgingival pathogen levels: a 24-month prospective multicenter cohort study

BACKGROUND

The diagnosis of the progression of periodontitis presently depends on the use of clinical symptoms (such as attachment loss) and radiographic imaging. The aim of the multicenter study described here was to evaluate the diagnostic use of the bacterial content of subgingival plaque recovered from the deepest pockets in assessing disease progression in chronic periodontitis patients.

METHODS

This study consisted of a 24-month investigation of a total of 163 patients with chronic periodontitis who received trimonthly follow-up care. Subgingival plaque from the deepest pockets was recovered and assessed for bacterial content of Porphyromonas gingivalis, Prevotella intermedia, and Aggregatibacter actinomycetemcomitans using the modified Invader PLUS assay. The corresponding serum IgG titers were measured using ELISA. Changes in clinical parameters were evaluated over the course of 24 months. The sensitivity, specificity, and prediction values were calculated and used to determine cutoff points for prediction of the progression of chronic periodontitis.

RESULTS

Of the 124 individuals who completed the 24-month monitoring phase, 62 exhibited progression of periodontitis, whereas 62 demonstrated stable disease. The P. gingivalis counts of subgingival plaque from the deepest pockets was significantly associated with the progression of periodontitis (p < 0.001, positive predictive value = 0.708).

CONCLUSIONS

The P. gingivalis counts of subgingival plaque from the deepest pockets may be associated with the progression of periodontitis.

PGE2 Activates Cementoclastogenesis by Cementoblasts via EP4

Destruction of cementum and alveolar bone is the main causative event for the exfoliation of teeth as a consequence of periodontitis. Prostaglandin E2 (PGE2) and PGE receptor subtypes (EPs) play an important role in modulating osteoblast-mediated osteoclastogenesis; however, no information is available on the role of PGE2 and EPs in regulating cementoblast-mediated cementoclastogenesis. We hypothesized that the PGE2-EPs pathway also regulates cementoblasts’ ability to activate cementoclasts. For these studies, OCCM-30 cells (a mouse cementoblast cell line) were exposed to PGE2 and specific EP agonists. PGE2 (100 ng/mL) and EP4 agonist (1 μM) up-regulated RANKL and IL-6 mRNA levels, while they down-regulated OPG mRNA expression. The EP4 antagonist (1 μM) eliminated these effects of PGE2. PGE2 treatment of co-cultures of OCCM-30 cells with bone marrow cells induced TRAP-positive cells via the EP4 pathway. These findings suggest that PGE2 promotes cementoblast-mediated cementoclastogenesis by regulating the expression of RANKL and OPG via the EP4 pathway.

Inducement of tissue regeneration of harvested hamstring tendons in a rabbit model

OBJECTIVES

The objective of this study was to determine if the use of fascia lata as a tendon regeneration guide (placed into the tendon canal following harvesting the semitendinosus tendon) would improve the incidence of tissue regeneration and prevent fatty degeneration of the semitendinosus muscle.

MATERIALS AND METHODS

Bilateral semitendinosus tendons were harvested from rabbits using a tendon stripper. On the inducing graft (IG) side, the tendon canal and semitendinosus tibial attachment site were connected by the fascia lata, which was harvested at the same width as the semitendinosus tendon. On the control side, no special procedures were performed. Two groups of six rabbits were killed at post-operative weeks 4 and 8, respectively. In addition, three healthy rabbits were killed to obtain normal tissue. We evaluated the incidence of tendon tissue regeneration, cross-sectional area of the regenerated tendon tissue and proportion of fatty tissue in the semitendinosus muscle.

RESULTS

At post-operative week 8, the distal end of the regenerated tissue reached the vicinity of the tibial insertion on the control side in two of six specimens. On the IG side, the regenerated tissue maintained continuity with the tibial insertion in all specimens. The cross-sectional area of the IG side was significantly greater than that of the control side. The proportion of fatty tissue in the semitendinosus muscle on the IG side was comparable with that of the control side, but was significantly greater than that of the normal muscle.

CONCLUSIONS

Tendon tissue regenerated with the fascia lata graft was thicker than naturally occurring regenerated tissue. However, the proportion of fatty tissue in the semitendinosus muscle was greater than that of normal muscle.Cite this article: K. Tabuchi, T. Soejima, H. Murakami, K. Noguchi, N. Shiba, K. Nagata. Inducement of tissue regeneration of harvested hamstring tendons in a rabbit model. Bone Joint Res 2016;5:247-252. DOI: 10.1302/2046-3758.56.2000585.

Salivary pathogen and serum antibody to assess the progression of chronic periodontitis: a 24-mo prospective multicenter cohort study

BACKGROUND AND OBJECTIVE

A diagnosis of periodontitis progression is presently limited to clinical parameters such as attachment loss and radiographic imaging. The aim of this multicenter study was to monitor disease progression in patients with chronic periodontitis during a 24-mo follow-up program and to evaluate the amount of bacteria in saliva and corresponding IgG titers in serum for determining the diagnostic usefulness of each in indicating disease progression and stability.

MATERIAL AND METHODS

A total of 163 patients with chronic periodontitis who received trimonthly follow-up care were observed for 24 mo. The clinical parameters and salivary content of Porphyromonas gingivalis, Prevotella intermedia and Aggregatibacter actinomycetemcomitans were assessed using the modified Invader PLUS assay, and the corresponding serum IgG titers were measured using ELISA. The changes through 24 mo were analyzed using cut-off values calculated for each factor. One-way ANOVA or Fisher's exact test was used to perform between-group comparison for the data collected. Diagnostic values were calculated using Fisher's exact test.

RESULTS

Of the 124 individuals who completed the 24-mo monitoring phase, 62 exhibited periodontitis progression, whereas 62 demonstrated stable disease. Seven patients withdrew because of acute periodontal abscess. The ratio of P. gingivalis to total bacteria and the combination of P. gingivalis counts and IgG titers against P. gingivalis were significantly related to the progression of periodontitis. The combination of P. gingivalis ratio and P. gingivalis IgG titers was significantly associated with the progression of periodontitis (p = 0.001, sensitivity = 0.339, specificity = 0.790).

CONCLUSIONS

It is suggested that the combination of P. gingivalis ratio in saliva and serum IgG titers against P. gingivalis may be associated with the progression of periodontitis.

Healing of localized gingival recessions treated with a coronally advanced flap alone or combined with an enamel matrix derivative and a porcine acellular dermal matrix: a preclinical study

OBJECTIVE

This study aimed to evaluate the effects of a porcine acellular dermal matrix (PADM) with or without an enamel matrix derivative (EMD) on gingival recession defects treated with a coronally advanced flap (CAF) in dogs.

MATERIALS AND METHODS

Miller class II gingival recession defects (5 mm wide and 7 mm deep) were surgically created on the labial side of bilateral maxillary canines in 12 dogs. After 8 weeks of plaque accumulation, the 24 chronic defects were randomly assigned to one of the following 4 treatments: CAF, CAF with PADM (CAF/PADM), CAF with EMD (CAF/EMD), and CAF with EMD and PADM (CAF/EMD/PADM). The animals were sacrificed 10 weeks after surgery for histologic evaluation.

RESULTS

In all groups, root coverage was obtained to a varying degree. PADM was well incorporated in gingival connective tissue in the CAF/PADM and in the CAF/EMD/PADM groups. The height of newly formed bone was significantly greater in the CAF/EMD/PADM group than in the CAF and CAF/PADM groups. New cementum with periodontal ligament-like tissue was predominantly found in the CAF/EMD and CAF/EMD/PADM groups. The CAF/EMD/PADM group showed the greatest amount of new cementum among the groups examined, although the difference was not statistically significant.

CONCLUSION

Within the limitations of the present study, it can be concluded that CAF/EMD/PADM treatment may promote periodontal regeneration in gingival recession defects.

CLINICAL RELEVANCE

The present results suggest that the combination of EMD and PADM in conjunction with CAF may represent a promising approach for treating single Miller class II gingival recessions.

A potential anti-allodynic mechanism of GDNF following L5 spinal nerve ligation; Mitigation of NPY up-regulation in the touch sense pathway

Intrathecal delivery of glial cell line-derived neurotrophic factor (GDNF) reverses mechanical allodynia after 5th lumbar (L5) spinal nerve ligation (SNL). However, the molecular mechanism behind this process is not fully understood. Following sciatic nerve injury, primary afferent neurons in the injured dorsal root ganglion (DRG) begin to express neuropeptide Y (NPY) that is absent in normal DRG. The aim of the current study was to determine the relationship of this de novo expression of NPY and the anti-allodynic effect of GDNF. Following L5 SNL, 73% of neurons began to express NPY mRNA in the ipsilateral L5 DRG and robust NPY-immunoreactive fibers appeared in the ipsilateral GN where the touch-sense mediating A-fiber primary afferents from the hindpaw terminate. Seven-daylong intrathecal infusion of GDNF at the L5 DRG level, starting on day three when mechanical allodynia had fully developed, reversed once-established these changes. The GN neurons normally expressed NPY Y1 receptor, but not Y2, Y4, or Y5 receptors, and L5 SNL did not change the expression pattern. Bolus intracisternal injection of BIBP3226, a Y1 receptor antagonist, dose-dependently reversed mechanical allodynia. We demonstrated that GDNF reversed once-established mechanical allodynia as well as NPY induction in the touch-sense processing pathway. NPY could facilitate touch-sense processing by Y1 receptor in the gracile nucleus after peripheral nerve injury. GDNF may exert anti-allodynic effects through mitigation of this NPY up-regulation. The effectiveness of delayed treatment further indicates the therapeutic potential of GDNF on neuropathic pain.

De novo expression of Nav1.7 in injured putative proprioceptive afferents: Multiple tetrodotoxin-sensitive sodium channels are retained in the rat dorsal root after spinal nerve ligation

Tetrodotoxin-sensitive (TTX-s) spontaneous activity is recorded from the dorsal roots after peripheral nerve injury. Primary sensory neurons in the dorsal root ganglion (DRG) express multiple TTX-s voltage-gated sodium channel α-subunits (Navs). Since Nav1.3 increases, whereas all other Navs decrease, in the DRG neurons after peripheral nerve lesion, Nav1.3 is proposed to be critical for the generation of these spontaneous discharges and the contributions of other Navs have been ignored. Here, we re-evaluate the changes in expression of three other TTX-s Navs, Nav1.1, Nav1.6 and Nav1.7, in the injured 5th lumbar (L5) primary afferent components following L5 spinal nerve ligation (SNL) using in situ hybridization histochemistry and immunohistochemistry. While the overall signal intensities for these Nav mRNAs decreased, many injured DRG neurons still expressed these transcripts at clearly detectable levels. All these Nav proteins accumulated at the proximal stump of the ligated L5 spinal nerve. The immunostaining patterns of Nav1.6 and Nav1.7 associated with the nodes of Ranvier were maintained in the ipsilateral L5 dorsal root. Interestingly, putative proprioceptive neurons characterized by α3 Na+/K+ ATPase-immunostaining specifically lacked Nav1.7 mRNA in naïve DRG but displayed de novo expression of this transcript following SNL. Nav1.7-immunoreactive fibers were significantly increased in the ipsilateral gracile nucleus where central axonal branches of the injured A-fiber afferents terminated. These data indicate that multiple TTX-s channel subunits could contribute to the generation and propagation of the spontaneous discharges in the injured primary afferents. Specifically, Nav1.7 may cause some functional changes in sensory processing in the gracile nucleus after peripheral nerve injury.

Chronological changes in the collagen-type composition at tendon-bone interface in rabbits

Objectives

The purpose of this study was to evaluate chronological changes in the collagen-type composition at tendon–bone interface during tendon–bone healing and to clarify the continuity between Sharpey-like fibres and inner fibres of the tendon.

Methods

Male white rabbits were used to create an extra-articular bone–tendon graft model by grafting the extensor digitorum longus into a bone tunnel. Three rabbits were killed at two, four, eight, 12 and 26 weeks post-operatively. Elastica van Gieson staining was used to colour 5 µm coronal sections, which were examined under optical and polarised light microscopy. Immunostaining for type I, II and III collagen was also performed.

Results

Sharpey-like fibres comprised of type III collagen in the early phase were gradually replaced by type I collagen from 12 weeks onwards, until continuity between the Sharpey-like fibres and inner fibres of the tendon was achieved by 26 weeks.

Conclusions

Even in rabbits, which heal faster than humans, an observation period of at least 12 to 26 weeks is required, because the collagen-type composition of the Sharpey-like fibre bone–tendon connection may have insufficient pullout strength during this period. These results suggest that caution is necessary when permitting post-operative activity in humans who have undergone intra-bone tunnel grafts.

Effects of EMD in combination with bone swaging and calcium phosphate bone cement on periodontal regeneration in one-wall intrabony defects in dogs

BACKGROUND AND OBJECTIVE

Although the application of EMD is a widely accepted periodontal-regenerative therapy, its effects on noncontained intrabony defects are unpredictable because of the lack of a space-making property. The combined use of EMD and autogenous bone grafts reportedly stimulates significant periodontal regeneration in intrabony defects. The aim of the present study was to evaluate the effects of EMD in combination with bone swaging (BS) and injectable calcium phosphate bone cement (CPC), which was placed into the spaces between the grafted swaged bone and the proximal host bone, on periodontal healing in one-wall intrabony defects in dogs.

MATERIAL AND METHODS

One-wall intrabony defects (3 mm wide and 5 mm deep) were surgically created on the mesial and distal sides of the bilateral mandibular premolars in four dogs. The 16 defects were assigned to one of the following treatments: EMD only, BS only, EMD with BS (EMD + BS), or EMD with BS and CPC (EMD + BS + CPC). The animals were killed 8 wk after surgery for histologic evaluation.

RESULTS

The height of newly formed bone was significantly greater in the EMD + BS + CPC group (3.73 ± 0.30 mm) than in the BS-only (2.74 ± 0.33 mm; p < 0.05) and EMD + BS (2.88 ± 0.98 mm; p < 0.05) groups. The area of newly formed bone was significantly larger in the EMD + BS + CPC group (5.68 ± 1.66 mm(2)) than in the EMD-only (3.68 ± 0.33 mm(2); p < 0.05), BS-only (3.48 ± 1.26 mm(2); p < 0.05) and EMD + BS (3.38 ± 1.37 mm(2); p < 0.05) groups. The EMD-only (4.63 ± 0.42 mm), EMD + BS (4.67 ± 0.30 mm) and EMD + BS + CPC (4.78 ± 0.54 mm) groups showed significantly greater cementum formation than did the BS-only group (3.93 ± 0.56 mm; p < 0.05).

CONCLUSION

These results indicate that treatment with EMD + BS + CPC promotes favorable periodontal healing in one-wall intrabony defects in dogs.

Intracranial dural arteriovenous fistula with retrograde cortical venous drainage: use of susceptibility-weighted imaging in combination with dynamic susceptibility contrast imaging

BACKGROUND AND PURPOSE

SWI is a new MR imaging method that maximizes sensitivity to magnetic susceptibility effects with phase information for visualizing small cerebral veins. The purpose of this study was to report the use of SWI in combination with DSC in examining related RCVD in patients with intracranial DAVFs.

MATERIALS AND METHODS

Ten patients with angiographically confirmed DAVFs with RCVD underwent conventional MR imaging, SWI, and DSC. The ability of SWI to depict dilated cerebral veins was evaluated and then compared with DSC. The hemispheres of patients with DAVFs were grouped into affected (with RCVD) or nonaffected (without RCVD) categories by angiography. Four patients had bilaterally affected hemispheres. A total of 14 affected hemispheres in patients with DAVFs with RCVD were evaluated.

RESULTS

SWI showed dilated cerebral veins on the surface of the brain in all (100%) of the 14 affected hemispheres in patients with DAVFs with RCVD and deep in the brain in 9 (64%). T2-weighted imaging showed prominent flow-voids on the surface of the brain in 10 (71%) of the 14 affected hemispheres in patients with DAVFs with RCVD and deep in the brain in 5 (36%). DSC showed increased cerebral blood volume in all of the 14 affected hemispheres. The SWI findings regarding dilated veins on the surface of the brain corresponded well with the areas of increased cerebral blood volume.

CONCLUSIONS

SWI in combination with DSC could be used to characterize the presence of RCVD in patients with DAVFs.

A case of tongue carcinoma associated with chronic graft-versus-host disease after allogeneic haematopoietic stem cell transplantation

Graft-versus-host disease (GVHD) can occur at various sites, including the oral mucosa, where it is associated with a high risk of head and neck cancer. We report the case of a 46-year-old woman with tongue cancer that developed following Hodgkin's lymphoma and chronic GVHD, and we discuss the possible causes of cancer development.

Laminae-specific distribution of alpha-subunits of voltage-gated sodium channels in the adult rat spinal cord

While the voltage-gated sodium channels (VGSCs) are the key molecules for neuronal activities, the precise distribution of them in spinal cord is not clear in previous studies. We examined the expression of mRNAs for alpha-subunits of VGSC (Navs) in adult rat spinal cord before and 7 days after L5 spinal nerve ligation (SPNL) or complete Freund's adjuvant (CFA)-induced paw inflammation by in situ hybridization histochemistry, reverse transcription-polymerase chain reaction, and immunohistochemistry. Nav1.1 and Nav1.6 mRNAs were present in all laminae, except for lamina II, including the spinothalamic tract neurons in lamina I identified by retrograde tracing of Fluoro-gold. Nav1.2 mRNA was predominantly observed in the superficial layers (laminae I, II), and Nav1.3 mRNA was more restricted to these layers. All these transcripts were expressed by the neurons characterized by immunostaining for neuron-specific nuclear protein. Nav1.7 mRNA was selectively expressed by a half of motoneurons in lamina IX. No signals for Nav1.8 or Nav1.9 mRNAs were detected. Immunohistochemistry for Nav1.1, Nav1.2, Nav1.6, and Nav1.7 proteins verified some of these neuronal distributions. L5 SPNL decreased Nav1.1 and Nav1.6 mRNAs, and increased Nav1.3 and Nav1.7 mRNAs in the axotomized spinal motoneurons, without any changes in other laminae of L4-6 spinal segments. Intradermal injection of CFA did not cause any transcriptional change. Our findings demonstrate that spinal neurons have different compositions of VGSCs according to their location in laminae. Pathophysiological changes of spinal neuronal activity may due to post-transcriptional changes of VGSCs. Comparison with our previous data concerning the subpopulation-specific distribution of Nav transcripts in primary afferent neurons provides potentially specific targets for local analgesics at the peripheral nerve and spinal levels.

Transient receptor potential A1 mediates gastric distention-induced visceral pain in rats

BACKGROUND

Transient receptor potential (TRP)A1, a member of the TRP family of ion channels, has been proposed to function in diverse sensory processes, including thermosensation and pain. However, TRPA1 has not been directly implicated in stomach mechanosensation, and its contribution to acute visceral pain from this organ is unknown. Here, we investigated the expression of TRPA1 in primary sensory afferents and its involvement in visceral hypersensitivity in rats.

METHODS

We examined TRPA1 expression in the dorsal root ganglion (DRG), nodose ganglion (NG), and stomach of rats by using immunohistochemistry. Electromyographic responses to gastric distention (GD) were recorded from the acromiotrapezius muscle in TRPA1 knockdown rats and in control rats.

RESULTS

TRPA1 was predominantly expressed with sensory neuropeptides in DRG and NG neurons, and in nerve fibres in the rat stomach. Gastric distention induced the activation of extracellular signal-regulated protein kinase 1/2 (ERK1/2) in DRG and NG neurons 2 min after stimulation, and most of the phosphorylated-ERK1/2-labelled DRG neurons were TRPA1-positive neurons. Intrathecal injection of TRPA1 antisense attenuated the visceromotor response, and suppressed ERK1/2 activation in the DRG, but not NG, neurons produced by GD. Furthermore, intrathecal and intraperitoneal injections of the TRPA1 inhibitor HC-03003 suppressed the response to noxious GD.

CONCLUSIONS

The activation of TRPA1 in DRG neurons by noxious GD may be involved in acute visceral pain. Our findings point to the potential blockade of TRPA1 in primary afferents as a new therapeutic target for the reduction of visceral hypersensitivity.

Evaluation of the inhibitory and induction potential of YM758, a novel If channel inhibitor, for human P450-mediated metabolism

This study was designed to examine the in vitro metabolism of YM758, a novel cardiovascular agent, and to evaluate its potential to cause drug interactions and induction of CYP isozymes. After incubation with pooled human liver microsomes, YM758 was converted to two major metabolites (AS2036313-00, and YM-394111 or YM-394112). The formation of AS2036313-00, and YM-394111 or YM-394112 were mediated by CYP2D6 and CYP3A4, respectively, which was elucidated by using a bank of human liver microsomes and recombinant CYP enzymes in combination with the utilization of typical substrates and inhibitors. The Ki values of YM758 for midazolam, nifedipine, and metoprolol metabolism ranged from 59 to 340 microM, being much higher than the YM758 concentration in human plasma. The formation of AS2036313-00, and YM-394111 or YM-394112 was inhibited by quinidine and ketoconazole with Ki values of 140 and 0.24 microM, respectively, which indicates that YM758 metabolism may be affected by coadministration of strong CYP2D6 and 3A4 inhibitors in vivo, given the clinical plasma concentrations of quinidine and ketoconazole. After human hepatocytes were exposed to 10 microM YM758, microsomal activity and mRNA level for CYP1A2 were not induced while those for CYP3A4 were slightly induced. The tested concentration was much higher than that in human plasma, which suggests that the induction potential of YM758 is also negligible.

Cyclooxygenase-2-derived prostaglandin E2 is involved in vascular endothelial growth factor production in interleukin-1alpha-stimulated human periodontal ligament cells

BACKGROUND AND OBJECTIVE

Prostaglandin E(2), which exerts its actions via EP receptors (EP1, EP2, EP3 and EP4), is a bioactive metabolite of arachidonic acid produced by cyclooxygenase-1 and/or cyclooxygenase-2. Interleukin-1alpha induces prostaglandin E(2) production via cyclooxygenase-2 in human periodontal ligament cells. Vascular endothelial growth factor is a key regulator of physiologic as well as pathologic angiogenesis and has been indicated to be involved in the pathology of periodontal diseases. In the present study, we investigated whether interleukin-1alpha induced vascular endothelial growth factor production in human periodontal ligament cells and whether cyclooxygenase-2-derived prostaglandin E(2) regulated interleukin-1alpha-induced vascular endothelial growth factor production.

MATERIAL AND METHODS

Human periodontal ligament cells were obtained from extracted teeth of periodontally healthy subjects. After pre-incubation with a nonselective cyclooxygenase-1/2 inhibitor, indomethacin or a selective cyclooxygenase-2 inhibitor (NS-398), periodontal ligament cells were treated with or without interleukin-1alpha, prostaglandin E(2), various EP receptor agonists and dibutyryl cAMP (a cAMP analogue). The levels of vascular endothelial growth factor and prostaglandin E(2) in the culture supernatant were measured by enzyme-linked immunosorbent assay. The vascular endothelial growth factor mRNA expression was evaluated by semiquantitative reverse transcription-polymerase chain reaction.

RESULTS

Interleukin-1alpha induced vascular endothelial growth factor production in a dose-dependent and time-dependent manner. The interleukin-1alpha-induced vascular endothelial growth factor mRNA and protein expression was inhibited to the same extent by indomethacin and NS-398. Indomethacin and NS-398 completely inhibited interleukin-1alpha-induced prostaglandin E(2) production. Exogenous prostaglandin E(2), butaprost (an EP2 receptor agonist) and dibutyryl cAMP abolished the inhibitory effect of indomethacin on interleukin-1alpha-induced vascular endothelial growth factor production.

CONCLUSION

We suggest that interleukin-1alpha induced vascular endothelial growth factor production via cyclooxygenase-2-derived prostaglandin E(2) in human periodontal ligament cells. The interleukin-1alpha/prostaglandin E(2) pathway might regulate vascular endothelial growth factor production in periodontal lesions.

Comparison of the kinetic characteristics of inhibitory effects exerted by biguanides and H2-blockers on human and rat organic cation transporter-mediated transport: Insight into the development of drug candidates

In this study, the comparison of the transport of substrates (1-methyl-4-phenylpydinium (MPP) and tetraethyl ammonium (TEA)) and the inhibition potency of the inhibitors (biguanides and H(2)-blockers) for human and rat organic cation transporters (hOCTs and rOcts), and the inhibition type of inhibitors for these transporters were investigated using HEK293 cells that stably express hOCT/rOct. The concentration-dependent uptake of [(3)H]-MPP and [(14)C]-TEA by hOCT1-3/rOct1-3 had K(m) values similar to those in the literature. It was also deduced that MPP and TEA are competitive inhibitors for hOCT1-2/rOct1-2. The K(i) values for phenformin inhibition of [(3)H]-MPP and [(14)C]-TEA uptake by hOCT1-3/rOct1-3 were lower than that for metformin. The [(3)H]-MPP uptake by hOCT1/rOct1 and hOCT3/rOct3 was inhibited by famotidine and ranitidine whereas that by hOCT2/rOct2 was not. The inhibitory potency of cimetidine for hOCT1-2 was very weak. In most cases, the differences in the V(max)/K(m) values of substrates and the K(i) values of inhibitors between hOCT and rOct were minor. The acquisition of information on OCT/Oct mediated-transport and/or inhibition such as that presented in this report is very useful for further understanding of certain aspects of uptake, distribution, and excretion for drug candidates.

Identification of the novel canine CYP1A2 1117 C>T SNP causing protein deletion

The pharmacokinetics of YM-64227 (4-cyclohexyl-1-ethyl-7-methylpyrido[2,3-d]-pyrimidine-2-(1H)-one), a novel and selective phosphodiesterase type 4 inhibitor, was characterized in beagle dogs. Based on the plasma parent drug to major hydroxylated metabolite ratio, 21 dogs were phenotyped as 16 extensive metabolizers (EM) and five poor metabolizers (PM). Nucleotide sequences of CYPs 1A2, 2B11, 2C21, 2D15, 2E1 and 3A12 were investigated in the EM and PM dogs. A CYP1A2 1117 C>T single nucleotide polymorphism was found, which resulted in an amino acid change from an Arg codon to a stop codon at position 373. All dogs phenotyped as PM were T/T homozygous, whereas EMs were C/C homozygous and C/T heterozygous. In Western blotting of liver microsomes, CYP1A protein expression was detected in the C/C and C/T types, but not in the T/T type. Of 65 dogs genotyped using genome DNA, the frequencies of the C and T alleles were 0.61 and 0.39, respectively, suggesting approximately 15% of the dogs would not express the CYP1A2 protein. The findings provide a coherent explanation for the inter-individual variability in the pharmacokinetics of CYP1A2 substrate drugs in dogs.

Tissue distribution of YM758, a novel If channel inhibitor, in pregnant and lactating rats

In this study the tissue distribution of radioactivity in pregnant and lactating rats was investigated by quantitatively determining radioactivity concentrations and by whole-body autoradioluminograms after a single oral administration of 14C-YM758. In addition, the transfer of radioactivity into the reproductive tissues, foetus, and milk is discussed in terms of the localization of transporters in syncytiotrophoblast and mammary gland. The radioactivity concentrations in the liver were the highest of all the tissues and organs tested at all the sampling times. The radioactivity in main tissues (liver and kidney), including reproductive tissues (amniotic fluid, placenta, ovary, and uterus), was not retained for a long time, as in the plasma. The tissue/plasma (T/P) ratio of radioactivity in the foetus was below 1.0, which might be due to Mdr1-mediated export of YM758 into blood via the blood-placenta barrier since YM758 is a substrate for hMDR1, not for hBCRP/rBcrp. The T/P ratio of radioactivity in the maternal milk 1 and 4 h after oral administration of 14C-YM758 was 7.2 and 11.0, respectively. To understand better the distribution of new drugs into the reproductive tissues/milk, and to interpret further the results of reproductive safety studies for drug development, the contribution of transporters expressed in the blood-placenta barrier and mammary gland to the drug-transfer into placenta and milk should be considered.