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）

金橋先生の論文がCommunications Biologyに受諾されました。

ヒト胎児の骨盤形態の性差はこれまでの報告よりもずっと早く、一次骨化の開始時にすでに明らかであることを、統計学的に示しました。

*内容は、京大HP等で紹介されました

Kanahashi T, Matsubayashi J, Imai H, Yamada S, Otani H, Takakuwa T. Sexual dimorphism of the human fetal pelvis exists at the onset of primary ossification, Communications Biology, 2024, 7:538, https://doi.org/10.1038/s42003-024-06156-y

Abstract
Human adolescent and adult skeletons exhibit sexual dimorphism in the pelvis. However, the degree of sexual dimorphism of the human pelvis during prenatal development remains unclear. Here, we performed high-resolution magnetic resonance imaging-assisted pelvimetry on 72 human fetuses (males [M]: females [F], 34:38; 21 sites) with crown-rump lengths (CRL) of 50–225 mm (the onset of primary ossification). We used multiple regression analysis to examine sexual dimorphism with CRL as a covariate. Females exhibit significantly smaller pelvic inlet anteroposterior diameters (least squares mean, [F] 8.4 mm vs. [M] 8.8 mm, P = 0.036), larger subpubic angle ([F] 68.1° vs. [M] 64.0°, P = 0.034), and larger distance between the ischial spines relative to the transverse diameters of the greater pelvis than males. Furthermore, the sacral measurements indicate significant sex-CRL interactions. Our study suggests that sexual dimorphism of the human fetal pelvis is already apparent at the onset of primary ossification.

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.

卒業研究発表会(後半）が開催されました（1/29,30）

ヒト胎児脳の一次脳溝形成過程の検討　熊谷美優

ヒト胎児期における骨盤内器官形成過程の三次元的解析　篠原李欧