NMNoritaka Maeta

Noritaka Maeta

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Previous Organizations / Institutes

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Noritaka Maeta has a total of 62 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Ureter reconstruction using a biotube in a canine model: A pilot study

    by Noritaka Maeta, Rosuke Iwai, Yohei Mochizuki, Natsuki Akashi, Masahiro Miyabe, Akira Matsuda, Kenji Kutara, Keisuke Sugimoto, Takamasa Itoi, Yasuhide Nakayama

    Ureteral injuries can lead to renal dysfunction, and conventional treatments such as ureteral stents and autologous tissue grafts have limitations. This study aimed to evaluate the biocompatibility of a "biotube" created using in-body tissue architecture (iBTA) technology for ureteral reconstruction in a canine model. Biotubes were implanted in dogs to replace a segment of the ureter. Ureteral stents were used to prevent obstruction. Autopsies were performed 2-3 months after implantation, and the implantation sites were examined histologically to assess tissue regeneration, vascularization, and potential inflammatory reactions. Ureteral stenting effectively prevented obstruction and ensured adequate urinary flow during the observation period. All biotubes were significantly shortened after implantation. No signs of inflammation or foreign body reactions were recorded, indicating good biocompatibility. Although epithelial cell invasion was observed, muscle tissue migration and angiogenesis were limited. Biotubes demonstrate potential as temporary ureteral substitutes; however, improvements in epithelialization and muscle tissue migration are necessary for successful long-term ureteral regeneration. Further experimental studies are required to evaluate their clinical utility as scaffold materials for ureteral reconstruction.


  • Open Access

    Evaluation of Skin Wound Healing with Biosheets Containing Somatic Stem Cells in a Dog Model: A Pilot Study

    by Noritaka Maeta, Ryosuke Iwai, Hiroshi Takemitsu, Natsuki Akashi, Masahiro Miyabe, Marina Funayama-Iwai, Yasuhide Nakayama

    The administration of mesenchymal stem cells (MSCs) has a positive effect on wound healing; however, the lack of adequate MSC engraftment at the wound site is a major limiting factor in current MSC-based therapies. In this study, a biosheet prepared using in-body tissue architecture (iBTA) was used as a material to address these problems. This study aimed to assess and evaluate whether biosheets containing somatic stem cells would affect the wound healing process in dogs. Biosheets were prepared by subcutaneously embedding molds in beagles. These were then evaluated grossly and histologically, and the mRNA expression of inflammatory cytokines, interleukins, and Nanog was examined in some biosheets. Skin defects were created on the skin of the beagles to which the biosheets were applied. The wound healing processes of the biosheet and control (no biosheet application) groups were compared for 8 weeks. Nanog mRNA was expressed in the biosheets, and SSEA4/CD105 positive cells were observed histologically. Although the wound contraction rates differed significantly in the first week, the biosheet group tended to heal faster than the control group. This study revealed that biosheets containing somatic stem cells may have a positive effect on wound healing.


  • Open Access

    Small Molecules Temporarily Induce Neuronal Features in Adult Canine Dermal Fibroblasts

    by Kiyotaka Arai, Fumiyo Saito, Masashi Miyazaki, Haruto Kushige, Yayoi Izu, Noritaka Maeta, Kazuaki Yamazoe

    Several methods have been developed to generate neurons from other cell types for performing regeneration therapy and in vitro studies of central nerve disease. Small molecules (SMs) can efficiently induce neuronal features in human and rodent fibroblasts without transgenes. Although canines have been used as a spontaneous disease model of human central nerve, efficient neuronal reprogramming method of canine cells have not been well established. We aimed to induce neuronal features in adult canine dermal fibroblasts (ACDFs) by SMs and assess the permanency of these changes. ACDFs treated with eight SMs developed a round-shaped cell body with branching processes and expressed neuronal proteins, including βIII-tubulin, microtubule-associated protein 2 (MAP2), and neurofilament-medium. Transcriptome profiling revealed the upregulation of neuron-related genes, such as SNAP25 and GRIA4, and downregulation of fibroblast-related genes, such as COL12A1 and CCN5. Calcium fluorescent imaging demonstrated an increase in intracellular Ca2+ concentration upon stimulation with glutamate and KCl. Although neuronal features were induced similarly in basement membrane extract droplet culture, they diminished after culturing without SMs or in vivo transplantation into an injured spinal cord. In conclusion, SMs temporarily induce neuronal features in ACDFs. However, the analysis of bottlenecks in the neuronal induction is crucial for optimizing the process.

  • Open Access

    Variation in Diffusion Tensor Imaging Parameters in the Cervical and Thoracic Spinal Cord (C1-C5 and C6-T2) Segments of Normal Beagle Dogs

    by Kiyotaka Arai, Takamasa Itoi, Natsuki Akashi, Masahiro Miyabe, Keisuke Sugimoto, Akira Matsuda, Noritaka Maeta, Teppei Kanda, Kenji Kutara

    This study aimed to determine the characteristics and reference values of each vertebra in the cervicothoracic region by performing diffusion tensor imaging (DTI) scans and analyzing DTI parameters in normal Beagle dogs. In five adult Beagles under anesthetic maintenance, DTI was performed using a 1.5-T magnetic resonance imaging (MRI) scanner. Axial DTI was performed using three overlapping slabs to cover the cervical and thoracic spinal cords. After post-processing, DTI parameters were calculated along the entire spinal cord. Among DTI parameters, fractional anisotropy, relative anisotropy, and axonal diffusivity significantly decreased in the caudal direction. However, the apparent diffusion coefficient, radial diffusivity, and mean diffusivity values were not significantly correlated with vertebral levels. We provide evidence for the existence of segment-dependent DTI parameters in the canine cervical spinal cord. Therefore, comparisons of DTI parameters between lesions at different vertebral levels should be avoided unless normative data are available. Furthermore, the DTI data obtained in this study may contribute to the development of a clinical reference for spinal cord evaluation in dogs using DTI parameters.

  • Open Access

    Effects of a Multimodal Approach Using Buprenorphine with/without Meloxicam on Food Intake, Body Weight, Nest Consolidating Behavior, Burrowing Behavior, and Gastrointestinal Tissues in Postoperative Male Mice

    by Kayo Furumoto, Yuka Sasaki, Masakatsu Nohara, Nagisa Takenaka, Noritaka Maeta, Teppei Kanda

    Distress affects animal welfare and scientific data validity. There is a lack of reports on the effects of multimodal analgesic approaches in mice. In this study, under the hypothesis that a multimodal analgesic protocol using buprenorphine with meloxicam has analgesic effects, we evaluated the effects of a multimodal analgesic protocol using buprenorphine with meloxicam on the well-being of mice during analgesic administration by changing the dosage of meloxicam. A total of 42 Slc:ICR male mice were categorized into nonsurgical and surgical groups (7 mice per group) and treated with an anesthetic (isoflurane) and analgesics (buprenorphine ± meloxicam). Analgesics were administered for 48 h after treatment. Buprenorphine (subcutaneous; 0.1 mg/kg/8 h) and meloxicam (subcutaneous; 0, 2.5, or 5 mg/kg/24 h) were administered twice. Body weight, food intake, nest consolidation score, and latency to burrow were evaluated. A significant decrease in food intake was observed 24 h after treatment, while a significant increase was observed 48 h post-treatment in all groups. Body weight showed a decreasing trend but was not significantly reduced. Furthermore, stomach, duodenum, and jejunum tissues showed no morphological abnormalities. Significant differences in burrow diving scores and the latency to burrow were observed between some groups, but these were not regarded as a consequence of the surgery and/or the meloxicam dose. When buprenorphine and meloxicam were combined, administering up to 5 mg/kg/day of meloxicam for 48 h to male mice after abdominal surgery had no significant negative effects on any tested parameters. In conclusion, a multimodal analgesic protocol of buprenorphine with meloxicam is among the options for increasing well-being in mice following abdominal surgery.


  • Modified Toyoda technique for total cystectomy and cutaneous ureterostomy in a cat

    by Noritaka Maeta, Kenji Kutara, Kanna Saeki, Fumio Hoshi

    Objectives To report the technique and outcome of a cat treated with a total cystectomy and bilateral cutaneous ureterostomy. Animals A 16-year-old male castrated domestic shorthair cat. Study design Case report. Case presentation A cat was referred after a 2-week history of pollakiuria and hematuria. Transitional cell carcinoma (TCC) was suspected based on ultrasonographic, cytologic, and contrast computed tomographic (CT) findings. A total cystectomy was combined with a modified cutaneous ureterostomy: the ureter, incised like a fish-mouth aperture, was anastomosed to the skin after the creation of a rectangular-shaped defect. Complete excision of a TCC was confirmed histologically. Results Ureteral stents were removed 7 days (left) and 28 days (right) postoperatively. The cat's incontinence was managed with an absorbent diaper surrounding the ureteral stomata. The right ureter became obstructed 14 months after surgery, and the cat died at home approximately 16 months after surgery. In spite of the urinary incontinence, the owner was satisfied with the surgery and evaluated the cat's quality of life as satisfactory. Conclusions The total cystectomy and cutaneous ureterostomy described here allowed urinary excretion and resulted in long-term survival of a cat with bladder TCC.


  • Open Access

    Effects of Multimodal Analgesic Protocol, with Buprenorphine and Meloxicam, on Mice Well-Being: A Dose Finding Study

    by Kayo Furumoto, Kumi Ogita, Tomomi Kamisaka, Asami Kawasumi, Koushi Takata, Noritaka Maeta, Takamasa Itoi, Masakatsu Nohara, Kaori Saeki, Teppei Kanda

    The anesthetic or analgesic agent of choice, route and frequency of anesthetic or analgesic administration, and stressors induce distress during the perioperative period. We evaluated a multimodal analgesic protocol using buprenorphine and meloxicam on the well-being of mice. Twenty-four Slc:ICR male mice were divided into control, anesthesia + analgesia, and surgery + anesthesia + analgesia groups. Tap water (orally: PO) and water for injection (subcutaneous: SC) were administered to the control group. Buprenorphine was administered twice (SC, 0.1 mg/kg/8 h) and meloxicam was administered thrice (PO, 5 mg/kg/24 h) to the anesthesia + analgesia and surgery + anesthesia + analgesia groups. The mice were subjected to laparotomy and assessed for several parameters. Even in absence of surgical pain, the anesthesia + analgesia group presented the same negative effects as the surgery + anesthesia + analgesia group. This multimodal analgesic protocol for mice was expected to have an analgesic effect on pain associated with laparotomy but was not sufficient to prevent food intake and weight decrease. This does not negate the need to administer analgesics, but suggests the need to focus on and care not only about the approach to relieve pain associated with surgery, but also other types of distresses to minimize negative side effects that may interfere with postoperative recovery in mice.


  • Open Access

    Comparative analysis of canine mesenchymal stem cells and bone marrow-derived mononuclear cells

    by Noritaka Maeta, Katsutoshi Tamura, Fuuna Ezuka, Hiroshi Takemitsu

    Background and aim: Mesenchymal stem cells (MSCs), which have multi-lineage differentiation potentials, are a promising source for regenerative medicine. However, the focus of study of MSCs is shifting from the characterization of the differentiation potential to their secretion potential for cell transplantation. Tissue regeneration and the attenuation of immune responses are thought to be affected by the secretion of multiple growth factors and cytokines by MSCs. However, the secretion potential of MSCs profiling remains incompletely characterized. In this study, we focused on the secretion ability related and protein mRNA expression of dog adipose tissue-derived MSCs (AT-MSC), bone marrow (BM)-derived MSCs, and BM-derived mononuclear cells (BM-MNC). Materials and Methods: Real-time polymerase chain reaction analyses revealed mRNA expression of nine growth factors and seven interleukins in these types of cells and three growth factors protein expression were determined using Enzyme-linked immunosorbent assay. Results: For the BM-MNC growth factors, the mRNA expression of transforming growth factor-beta (TGF-beta) was the highest. For the BM-derived MSC (BM-MSC) and AT-MSC growth factors, the mRNA expression of vascular endothelial growth factor (VEGF) was highest. BM-MSCs and AT-MSCs showed similar expression profiles. In contrast, BM-MNCs showed unique expression profiles for hepatocyte growth factor and epidermal growth factor. The three types of cells showed a similar expression of TGF-beta. Conclusion: We conclude that expression of cytokine proteins and mRNAs suggests involvement in tissue repair and protection.


  • Open Access

    Dysuria Associated with Non-Neoplastic Bone Hyperplasia of the Os Penis in a Pug Dog

    by Noritaka Maeta, Takako Shimokawa Miyama, Kenji Kutara, Teppei Kanda, Ikki Mitsui, Akihiro Ohnishi, Masahiro Miyabe, Yuki Shimizu, Kaori Saeki, Yasuhiko Okamura, et al.

    A three-year-old male Pug presented with a three-year history of urolithiasis and repeated urethral obstruction. Biochemical analysis, ultrasonography, and retrograde urethrocystography revealed probable portosystemic shunt and incomplete urethral obstruction due to uric acid ammonium calculi. Enhanced computed tomography (CT) revealed portosystemic shunt and proliferation of the osseous tissue of the os penis, which was surgically removed. Histopathologically, the excised osseous tissue comprised bland lamellar bone without atypia or inflammation. Hyperplasia of the os penis was diagnosed based on the image findings and histopathology. The dysuria improved postoperatively. This is the first report of dysuria associated with non-neoplastic bone hyperplasia of the os penis in a dog. Careful evaluation of the os penis by CT is needed for accurate diagnosis in case of repeated penile urethral obstruction.


  • Open Access

    The Outcome and CT Findings of Low-Dose Intensity Modulated Radiation Therapy with SQAP in a Cat with Thymoma

    by Kenji Kutara, Yohei Mochizuki, Akihiro Ohnishi, Ikki Mitsui, Teppei Kanda, Akihiko Sugiyama, Noritaka Maeta, Kosuke Kobayashi, Yuki Shimizu, Yasuhiko Okamura, et al.

    A 9-year-old male intact domestic cat weighing 4.6 kg was referred for tachypnea. A large mass was visible in computed tomography (CT) scans of the thoracic cavity. A histopathological evaluation of the mass was consistent with thymoma. The cat was treated with 2 × 8 Gy intensity modulated radiation therapy and sulfoquinovosyl acyl propanediol (SQAP). Post radiation therapy (RT), the tumor structure appeared cystic in the CT, and the tumor volume decreased by approximately 80% after aspiration than that before aspiration. The tumor was removed surgically. RT treatment with SQAP made it possible to treat the thymoma with a low total radiation dose.