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YAMAGISHI Kotaro

    Department of Medicine　Lecturer in Medical School
Last Updated :2024/04/25

Researcher Information

J-Global ID

Research Areas

  • Life sciences / Orthopedics

Published Papers

  • Shigeshi Mori; Masao Akagi; Akihiro Moritake; Ichiro Tsukamoto; Kotaro Yamagishi; Shinji Inoue; Koichi Nakagawa; Daisuke Togawa
    The journal of knee surgery 36 (5) 555 - 561 2023/04 
    There has been no consensus about how to determine the individual posterior tibial slope (PTS) intraoperatively. The purpose of this study was to investigate whether the tibial plateau could be used as a reference for reproducing individual PTS during medial unicompartmental knee arthroplasty (UKA). Preoperative computed tomography (CT) data from 48 lower limbs for medial UKA were imported into a three-dimensional planning software. Digitally reconstructed radiographs were created from the CT data as the lateral knee plain radiographs and the radiographic PTS angle was measured. Then, the PTS angles on the medial one-quarter and the center of the MTP (¼ and ½ MTP, respectively), and that on the medial tibial eminence (TE) were measured on the sagittal multiplanar reconstruction image. Finally, 20 lateral knee radiographs with an arthroscopic probe placed on the ¼ and the ½ MTP were obtained intraoperatively, and the angle between the axis of the probe and the tangent line of the plateau was measured. The mean radiographic PTS angle was 7.9 ± 3.0 degrees (range: 1.7-13.6 degrees). The mean PTS angles on the ¼ MTP, the ½ MTP, and the TE were 8.1 ± 3.0 degrees (1.2-13.4 degrees), 9.1 ± 3.0 degrees (1.4-14.7 degrees), and 9.9 ± 3.1 degrees (3.1-15.7 degrees), respectively. The PTS angles on the ¼ MTP and the ½ MTP were strongly correlated with the radiographic PTS angle (r =0.87 and 0.80, respectively, p < 0.001). A statistically significant difference was observed between the mean angle of the radiographic PTS and the PTS on the TE (p < 0.01). The mean angle between the axis of the probe and the tangent line of the tibial plateau was -0.4 ± 0.9 degrees (-2.3-1.3 degrees) on the ¼ MTP and -0.1 ± 0.7 degrees (-1.5-1.2 degrees) on the ½ MTP, respectively. An area from the medial one-quarter to the center of the MTP could be used as an anatomical reference for the individual PTS.
  • Masao Akagi; Akihiro Moritake; Kotaro Yamagishi; Shigeshi Mori; Koichi Nakagawa; Hisafumi Aya
    Arthroplasty today 18 89 - 94 2022/12 
    BACKGROUND: There is currently no consensus on intraoperative references for determining the posterior tibial slope (PTS) in medial unicompartmental knee arthroplasty (UKA). The medial tibial plateau could serve as a direct reference for determining the native PTS through the placement of a hook probe in the anteroposterior direction of the medial tibial plateau. This study aimed to examine the accuracy of this new referencing method. METHODS: We consecutively performed 55 medial UKAs using our new method (study group), and the preoperative and postoperative PTS on lateral knee radiographs were examined. These outcomes were then compared with those of consecutive 50 medial UKAs performed using the conventional method (control group), which immediately preceded the start of the use of the new method. RESULTS: The correlation coefficient between the preoperative and postoperative PTS of the study group was larger than that of the control group (0.887 and 0.482, respectively). The mean implantation error of the PTS in the study group was smaller than that of the control group (-1.1° ± 1.3° and -3.0° ± 3.2°, respectively; P < .0001). The percentages of knees within 2° of implantation error were 73% and 34% in the study and control groups, respectively (P < .0001). The root mean square errors in the study and control groups were 1.7° and 4.3°, respectively. CONCLUSIONS: The direct referencing method with a probe can significantly improve the accuracy of tibial sagittal alignment.
  • Maki Itokazu; Yuta Onodera; Tatsufumi Mori; Shinji Inoue; Kotaro Yamagishi; Akihiro Moritake; Natsumi Iwawaki; Kanae Shigi; Toshiyuki Takehara; Yuji Higashimoto; Masao Akagi; Takeshi Teramura
    The Journal of biological chemistry 298 (7) 102098 - 102098 2022/07 
    Sarcopenia is an aging-associated attenuation of muscular volume and strength and is the major cause of frailty and falls in elderly individuals. The number of individuals with sarcopenia is rapidly increasing worldwide; however, little is known about the underlying mechanisms of the disease. Sarcopenia often copresents with obesity, and some patients with sarcopenia exhibit accumulation of peri-organ or intra-organ adipose tissue as ectopic fat deposition, including atrophied skeletal muscle. In this study, we showed that transplantation of the perimuscular adipose tissue (PMAT) to the hindlimb thigh muscles of young mice decreased the number of integrin α7/CD29-double positive muscular stem/progenitor cells and that the reaction was mediated by PMAT-derived exosomes. We also found that the inhibition of cell proliferation was induced by Let-7d-3p miRNA that targets HMGA2, which is an important transcription factor for stem cell self-renewal, in muscular stem/progenitor cells and the composite molecular reaction in aged adipocytes. Reduction of Let-7 miRNA repressor Lin28 A/B and activation of nuclear factor-kappa B signaling can lead to the accumulation of Let-7d-3p in the exosomes of aged PMAT. These findings suggest a novel crosstalk between adipose tissue and skeletal muscle in the development of aging-associated muscular atrophy and indicate that adipose tissue-derived miRNAs may play a key role in sarcopenia.
  • Shinji Inoue; Kazuhiko Hashimoto; Kotaro Yamagishi; Koichi Nakagawa; Masao Akagi
    International journal of surgery case reports 88 106483 - 106483 2021/11 
    INTRODUCTION AND IMPORTANCE: Factors that affect patellofemoral (PF) osteoarthritis (OA) after unicompartmental knee arthroplasty (UKA) remain unclear. We report a case in which the lateral placement of the femoral component resulted in rapidly progressive OA in the medial patellar facet. CASE PRESENTATION: The patient was an 84-year-old woman who had increased pain in the left knee due to varus knee OA for 1 year and underwent medial UKA. One month after the surgery, the patient complained of limited knee flexion of 90° with anterior knee pain, and around 7-mm lateral placement of the femoral component was observed on a postoperative radiograph and computed tomography scan. Six months after the surgery, rapidly progressive OA with subchondral bone depression in the medial facet was observed and this has been ongoing till the last follow-up of 3 years. The knee flexion is limited 105° now, and the patient complains of quadriceps weakness with anterior knee pain when stair-climbing and standing up from a chair. CLINICAL DISCUSSION: Lateral placement of the femoral component in medial UKA may cause progressive PF OA with limited knee flexion and anterior knee pain, which could be attributed to impingement between the femoral component and the medial patellar facet. CONCLUSION: Surgeons should be careful regarding the lateral placement to prevent symptomatic PF OA from occurring after medial UKA.
  • Ichiro Tsukamoto; Masao Akagi; Shigeshi Mori; Shinji Inoue; Koichi Nakagawa; Kotaro Yamagishi
    The Knee 27 (5) 1458 - 1466 2020/10 
    BACKGROUND: There is no consensus regarding how best to determine the tibial rotational alignment in unicompartmental knee arthroplasty (UKA). The purpose of this study was to clarify whether using the substitute anteroposterior (sAP) line of the tibia, as has recently been proposed, can improve tibial rotation. METHODS: The study included 57 consecutive medial UKAs. From May 2015 to September 2016, 28 knees in 28 patients underwent UKA using the medial intercondylar ridge (MIR) line as the tibial anteroposterior (AP) reference (MIR group). From October 2016 to March 2018, 29 knees in 29 patients underwent UKA using the sAP line (sAP group). In both groups, the external rotation angle of the tibial component relative to a line perpendicular to the surgical epicondylar axis was measured using computed tomography-based three-dimensional preoperative planning software for TKA and UKA. RESULTS: The mean external rotation angles of the tibial component in the MIR and sAP groups were 5.2° ± 8.5° (range, -12.4° to 20.8°) and 0.7° ± 3.2° (range, -6.0° to 7.4°), respectively (unpaired t test, P = 0.014). The variation in the external rotation angle of the tibial component was significantly smaller in the sAP group than in the MIR group (F test, P < 0.0001), as was the number of the outliers with more than ±5° error (Fisher's exact test, P < 0.0001). CONCLUSIONS: The use of the sAP line as the AP reference could improve and stabilize the rotational orientation of the tibial component in UKA procedures.
  • Kotaro Yamagishi; Ichiro Tsukamoto; Fumihisa Nakamura; Kazuhiko Hashimoto; Kazuhiro Ohtani; Masao Akagi
    European journal of histochemistry : EJH 62 (3) 2018/07 
    Epidemiological studies have shown an association between hypertension and knee osteoarthritis (OA). The purpose of this study was to investigate whether activation of the renin-angiotensin system (RAS) can aggravate mechanical loading-induced knee OA in mice. Eight-week-old male Tsukuba hypertensive mice (THM) and C57BL/6 mice were divided into running and non-running groups. Mice in the running group were forced to run (25 m/min, 30 min/day, 5 days/week) on a treadmill. All mice in the four groups (n=10 in each group) were euthanized after 0, 2, 4, 6, or 8 weeks of running or natural breeding. Cartilage degeneration in the left knees was histologically evaluated using the modified Mankin score. Expression of Col X, MMP-13, angiotensin type 1 receptor (AT1R), and AT2R was examined immunohistochemically. To study the effects of stimulation of the AT1R in chondrocytes by mechanical loading and/or Angiotensin II (AngII) on transduction of intracellular signals, phosphorylation levels of JNK and Src were measured in bovine articular chondrocytes cultured in three-dimensional agarose scaffolds. After 4 weeks, the mean Mankin score for the lateral femoral condylar cartilage was significantly higher in the THM running group than in the C57BL/6 running group and non-running groups. AT1R and AT2R expression was not detected at 0 weeks in any group but was noted after 4 weeks in the THM running group. AT1R expression was also noted at 8 weeks in the C57BL/6 running group. The expression levels of AT1R, COL X, and MMP-13 in chondrocytes were significantly higher in the THM running group than in the control groups. Positive significant correlations were noted between the Mankin score and the rate of AT1R-immunopositive cells, between the rates of AT1R- and Col X-positive cells, and between the rates of AT1R- and AT2R-positive cells. The phosphorylation level of JNK was increased by cyclic compression loading or addition of AngII to the cultured chondrocytes and was reversed by pretreatment with an AT1R blocker. A synergistic effect on JNK phosphorylation was observed between compression loading and AngII addition. Transgene activation of renin and angiotensinogen aggravated mechanical load-induced knee OA in mice. These findings suggest that AT1R expression in chondrocytes is associated with early knee OA and plays a role in the progression of cartilage degeneration. The RAS may be a common molecular mechanism involved in the pathogenesis of hypertension and knee OA.

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