京都大学 大学院医学研究科 人間健康科学系専攻 病理学研究室（形態形成医療科学）

岩佐さんの腹直筋腱画についての論文がJ Anatomyに受諾されました。MRI_DTIを用いて腹直筋腱画形成過程を検討しました。

• 胎児期早期の腹直筋腱画形成過程について、数、大きさ、タイプ、側方性、性別による検討を拡散テンソル画像を用いて行った。
• 両側の腱性交差の平均数は3.1（範囲：2.0-4.0）であり、21％の検体では腱性交差は2つだけであった。
• 腱性交差の形成における帯状の違いは、これまでの成人の研究で観察されたものとほぼ一致していた。拡散テンソル画像は、腱性交差部形成の早期分化を検出することができ有用であった。

Iwasa Y, KanahashiT, ImaiH, OtaniH, YamadaS, Takakuwa T. Formation of tendinous intersections in the human fetal rectus abdominis, J Anatomy 2024, in press

Abstract

Previous studies have poorly described the initial development process of the tendinous intersections of the rectus abdominis muscle (RAM). The present study aimed to observe the formation of tendinous intersections in the RAM during the early fetal period using diffusion tensor imaging (DTI). Fifteen human fetal specimens (crown-rump length [CRL]: 39.5–93.7 mm) were selected. Three-dimensional measurements revealed that Zone-4 (i.e., the zone between the pubic symphysis and the caudal base of the umbilical ring in the RAM) had a smaller width and was thicker than Zone-1 and Zone-2 (i.e., the zones between the costal arch and the cranial base of the umbilical ring) and Zone-3 (i.e., the zone at the umbilical ring). Characteristics of tendinous intersections in the RAM during the early fetal period were assessed according to number, size, type, laterality, and sex. The mean number of tendinous intersections on both sides was 3.1 (range: 2.0–4.0), and 21% of specimens had only two tendinous intersections, which was higher than that reported in previous adult studies. The present data suggest that the formation of tendinous intersections was still in progress in specimens with two tendinous intersections in the RAM and that the third tendinous intersection was formed in Zone-2. Ordinal logistic regression via generalized estimating equations revealed that the odds for a higher type of tendinous intersections in Zone-1 and Zone-2 were significantly higher than those in Zone-4 (adjusted odds ratio: 14.85, 8.84). The odds for the presence of incomplete types (tendinous intersections that could not completely transverse the RAM) in Zone-3 were significantly higher than those in Zone-1 (adjusted odds ratio: 7.4). The odds for missing tendinous intersections in Zone-4 were significantly higher than those in Zone-1 (adjusted odds ratio: 20.5). These zonal differences in the formation of tendinous intersections were consistent with those observed in previous adult studies. In this study, DTI detected tendinous intersections in a sample with a CRL of 45.8 mm (approximately 11 weeks of gestation), which is earlier than that in previous histological findings, indicating that the RAM does not have mature tendinous intersections until the 17th week of gestation. In conclusion, DTI could detect the premature differentiation of tendinous intersection formation. Our data may aid in elucidating the developmental processes of tendinous intersections in the RAM.

腎臓の高さの左右差についてがCongenital Anomaliesに掲載されました。

胚子期の腎臓の上昇、回転についてはこれまでよく知られていましたが、腎臓の高さの左右差については不明でした。本研究では、胚子期に左右腎臓の高さに違いはなく、ともに上昇すること、胎児期初期になると右側が左側よりも高くなることを示しました。胎児期の腎臓上昇の様子は、胚子期とは傾向が異なり別の機序を考える必要があります。

Ishiyama-Takara H, Matsubayashi J, Yamada S, Tetsuya Takakuwa T, Height difference between the right and left metanephroi during early human fetal development, Congenit Anom 64(3) 164-166, 2024.

Marieさんの論文がPLoS Oneに掲載されました。PLoS Oneは査読が早い印象がありましたが、今回の初回の査読は７ヶ月もかかりました。読んでくれる研究者がみつからなかったのでしょうか。

Marieさんの博士論文として申請、審査を受ける予定です。

Saizonou MA, Kitazawa H, Kanahashi T, Yamada S, Takakuwa T, Epithelial development of the urinary collecting system in the human embryo, PLOS ONE 19(4):　e0301778.　https://doi.org/10.1371/journal.pone.0301778

Abstract

The urinary collecting system (UCS) consists of organized ducts that collect urine from the nephrons and transport it to the ureter and bladder. Understanding the histogenesis of the UCS is critical. Thirty human embryos between the Carnegie stages (CS) 18 and 23 were selected from the Congenital Anomaly Research Center, Kyoto, Japan. Epithelia of the UCS, ureter, and bladder of each sample were randomly selected. Histological findings of the epithelia were analyzed according to the following criteria: type of epithelium, presence or absence of glycogen, percentage of migrated nuclei, percentage of cells in mitosis, and the surrounding mesenchyme. A thickened epithelium lining a narrow luminal cavity was observed in the pre-expanded pelvic specimens at CS18-CS23. At CS23, after pelvic expansion, the UCS showed a thin epithelium with a large luminal cavity mainly located on the early branches, whereas the epithelium covering the subsequent branches had medium thickness. Histological characteristics differed depending on the UCS part and sample stage. The degree of differentiation was evaluated, revealing that in CS18-CS23 pre-expanded pelvis specimens, the undifferentiated epithelium was found in the zeroth to third/fifth generation, whereas at CS23, after pelvic expansion, a differentiated epithelium covered the UCS zeroth to seventh generation. In a comparison of the urothelial epithelium between the UCS, ureter, and bladder, we found that urinary tract differentiation may be initiated in the bladder, followed by the ureter, UCS zeroth to seventh generations, and finally, UCS eighth to end generations. An understanding of the histogenesis of embryonic stage UCS can aid in the clinical management of congenital urinary tract defects and other diseases.

岩佐さんの錐体筋の形成についての論文がCongenit Anomに受諾されました。雑誌の表紙に採用されました。

Iwasa Y, Kanahashi T, Imai H, Otani H, Yamada S, Takakuwa T, Pyramidalis muscle formation during human embryonic and early fetal periods, Congenit Anom 2024, 64, 32-39, DOI: 10.1111/cga.12551

錐体筋という腹壁前壁下部にある筋肉の形成について検討しました。

表紙に採用されました。https://doi.org/10.1111/cga.12522

• 錐体筋は、前腹壁にある一対の小さな三角形の、役割の不明な筋
• 高分解能磁気共鳴イメージングを用いて、錐体筋がいつ出現したか、その特徴は何かを明らかにすることを目的とした
• CS18―23までの14個の胚子、59個の胎児（CRL：39.5-185.0mm）を選択した。
• 錐体筋の形成は胚子期後期(CS20ごろ)にみられ、胎児期初期における錐体筋の頻度、左右差、性差、空間的位置は成体と同様であった。

The pyramidalis muscle (PM) is a paired small triangular muscle of the anterior abdominal wall, the physiological significance of which remains unclear. Recent studies have failed to detect this muscle during the embryonic period. Hence, the present study aimed to determine when PM emerged and reveal its features using high-resolution magnetic resonance imaging. Fourteen embryos between Carnegie stage (CS)18 and CS23 and 59 fetuses (crown-rump length: 39.5–185.0 mm) were selected for this study. The PM was first detected in one of the three samples at CS20. It was detected in five of the seven samples (71.4%) between CS21 and CS23. Forty-eight samples (81.4%) at early fetal period had PMs on both the right and left sides, and three (5.1%) had that only on the right side. Eight samples (13.6%) had no PMs. No side-differences or sexual dimorphisms were detected. The PM length was larger than the width in most samples, although the length/width ratio varied among the samples. The PM/rectus abdominis muscle length and PM/umbilicus-pubic symphysis length ratios were almost constant, irrespective of the crown-rump length. The PM is located ventrally inferior to the rectus abdominis and closer to the medial muscle groups of the lower limb than the rectus abdominis. The present study demonstrated that PM formation occurred in the late embryonic period, and that the frequency, side differences, sex dimorphism, and spatial position of the PM in the early fetal period were similar to those in adults.