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）

石田さんの修士論文がJ Anatomyに受諾されました。胚子期から胎児期初期の中腸の形成に伴う太さについて検討しました。口側から肛門側へと太さが漸減する様子は美しいです。

Ishida, N, Kanahashi T, Matsubayashi J, Imai, H, Männer J, Yamada S, Takakuwa,T. Change in diameters of the small intestine according to embryonic and early fetal growth. 2025. J Anatomy in press

• ヒト発生の生理的臍帯ヘルニア期から還納期の14体の標本を対象に小腸の直径を口側から肛門側まで連続的に測定し、成長に伴う直径の変化を評価
• 空腸回腸において口側から肛門側にかけての腸管径の緩やかな変化
• 十二指腸と空腸回腸の差異が明瞭
• 十二指腸の前腸由来、中腸由来であることの差異
• 消化管の臍帯腔から腹腔への動的な位置変化、腸管の急速な伸長と複雑なループ形成は、腸管径の変化にほとんど影響を与えない
• 直径の増加は腸管の発達と分化の有用な指標となる可能性があることを示唆

Abstract
No previous studies have examined the diameter of the small intestine successively from the oral to the anal side of the small intestine. Therefore, the objectives of this study were to determine the successive intestinal diameters from the oral to the anal side (proximal to the distal) of the intestine, evaluate changes in diameter associated with growth, examine the effects of positional variation along the intestinal tract, investigate dynamic positional change from the extraembryonic coelom to the abdominal cavity, and assess the impact of complex tertiary intestinal loop formation.
To this end, 14 human embryonic and fetal specimens with crown-rump lengths (CRLs) ranging from 25.6 to 69.0 mm were selected for high-resolution magnetic resonance imaging acquisition. The small intestines of the specimens were located in the extraembryonic coelom (herniation phase), transitioning phase, or abdominal cavity (return phase). The small intestine and mesentery were reconstructed in three dimensions, and the resulting morphological changes were observed and analyzed. Successive intestinal diameters from the oral to anal side of the small intestine were determined. Specifically, we observed the following: 1) gradual changes in the diameter of the position from the oral to the anal side in the jejunum-ileum, 2) the difference between the duodenum and jejunum-ileum, and 3) the difference between the superior part of the duodenum derived from the foregut and the remaining parts derived from the midgut. 4) Notably, the dynamic positional change from the extraembryonic coelom to the abdominal cavity, along with the rapid elongation and complex intestinal loop formation—a conspicuous phenomenon in the embryonic and early fetal periods—had little effect on the changes in diameter. This study indicates that increased diameter may serve as a useful indicator of intestinal development and differentiation, independent of tertiary intestinal loop formation and positional changes into and out of the abdominal cavity.

第130回日本解剖学会で発表しました。(2025.3.17-19, 幕張メッセ)

■ 須藤紗帆、松林 潤、金橋 徹、今井 宏彦、大谷 浩、山田重人、高桑徹也；ヒト胚子期・胎児期初期における舌筋発生の検討 (The Development of the Tongue Muscles in the Human Embryonic and Fetal Period)

■ 八田 桃佳、金橋 徹、今井 宏彦、大谷 浩、山田 重人、高桑 徹也；拡散テンソル画像を用いた水晶体線維細胞の配向性の検討 (Analysis of lens fiber cells orientation in human embryonic and early fetal period using diffusion tensor imaging)

■ 石田 七彩、植田 優生、掛谷 真樹、松林 潤、金橋 徹、今井 宏彦、大谷 浩、山田 重人、高桑 徹也；中腸ループ形成を決定する要因：中腸の長さ、直径および位置の影響 (Factors determining midgut loop formation: The impact of midgut length, diameter, and location):

Graduate Student Presentation Award受賞しました!!

■ 熊谷 美優、金橋 徹、今井 宏彦、大谷 浩、多賀 厳太郎、高桑 徹也；高解像度MRIを用いたヒト胎児における大脳基底核原基の形成過程の検討 (Ganglionic Eminences Formation in the Human Fetus)

■ 青江 春菜、金橋 徹、今井 宏彦、大谷 浩、山田 重人、高桑 徹也；ヒト胎児期初期における上顎・下顎・歯胚の三次元解析 (Three-dimensional analysis of maxilla, mandible, and teeth at early human fetal stage) 

■ 倭 友希、松田 幸樹、松林 潤、金橋 徹、今井 宏彦、米山 明男、山田 重人、高桑 徹也；ヒトの胚子期における足部・手部の形態形成 (Foot and hand morphogenesis during human embryonic development)

■ 金橋 徹、松林　潤、今井 宏彦、山田 重人、大谷 浩、高桑 徹也；ヒト胎児期初期における骨盤傾斜角の検討 (Analysis of human pelvic tilt angle in the early fetal period)

■ 藤井瀬菜、山田重人、高桑徹也：胚子の体軸がらせん状を描くか否か (Does the embryo’s body axis have a right-handed helical shape? : analysis of 3D reconstructions)

医動物学実習で使用する寄生虫スライド標本のデジタル化の取り組みについて発表しました。第36回日本臨床微生物学会総会（名古屋：2025/1/24-26）

バーチャルスライドを活用した寄生虫学・医動物学教育の試み：

金橋　徹、伊吹謙太郎、山田　稔、高桑徹也

石田さんの修士論文の一部がJ Anatomyに受諾されました

CS16からCS23までの合計47個のヒト胚の高解像度の磁気共鳴画像取得し、中腸のヘルニア期に中腸と腸間膜で時間の経過とともに生じる形態学的変化を検討、二次ループと三次ループの初期形成、それに続く追加ループの形成を正確に記載しました。この研究の知見は、ループ形成における遺伝的要因と生体力学的要因の役割を包括的に理解する上で極めて重要です。

71. Ishida N, Ueda Y, Kanahashi T, Matsubayashi J, Imai H, Yamada S, Takakuwa T.Hierarchical loop formation in human midgut during physiological umbilical herniation, J Anatomy 2024, in press DOI:10.1111/joa.14228

• CS16からCS18までのすべての標本で一次ループの形成が観察された。
• 腸間膜狭窄により中腸がを 4 つのセグメントに分割可能。
• 中腸の二次ループは、最初にCS19のセグメント2と4（S2とS4）で識別。
• 三次ループの形成は、CS21 で最初に確認
• CS23 までに、三次ループはほとんどの標本のS2,3,4のセグメントで観察
• S1は1つの二次ループのまま。
• 三次ループの数は頭殿長に応じて増加し、中腸の S2 から S4 で最大 19 個
• ループ形成における遺伝的要因と生体力学的要因の役割を包括的に理解する上で極めて重要

Abstract

The primary loop, a single hairpin-shaped loop, becomes recognizable at the Carnegie stage (CS) 16. This loop projects toward the umbilical cord and subsequently gives rise to four secondary loops in the midgut of human embryos. As development advances, the segments corresponding to each secondary loop further develop into an increasing number of loops, referred to as tertiary loops. The mesenteric leaves and the narrowing parts, which serve as the borders of the secondary loops, remain identifiable throughout the subsequent stages of development. This study aimed to describe the morphological alterations that occur in the midgut and mesentery over time during the herniated phase of the midgut. A total of 47 human embryos between CS16 and CS23 and two fetuses in the physiological umbilical herniated stage were selected for high-resolution magnetic resonance imaging acquisition. Specimens were obtained from the Congenital Anomaly Research Center of Kyoto University. Serial tissue sections obtained from four embryos were subjected to histological observation. The midgut and mesentery were reconstructed in three dimensions, and the resulting morphological changes were observed and analyzed. Formation of the primary loop was observed in all specimens between CS16 and CS18. Secondary loops in the midgut were initially discerned at CS19 in segments 2 and 4 (S2 and S4). The border between S3 and S4 was identified at the apex of the midgut hernia, where traces of the vitelline artery and duct enter the mesentery. At CS21 and later stages of development, the presence of three borders at the exact location delineated by mesenteric narrowing was consistently observed, which resulted in the midgut being divided into four segments in all specimens. The formation of tertiary loops was initially identified at Carnegie stage (CS) 21, occurring in either segment S2 or S3. By CS23, tertiary loops were observed in three segments in most specimens. Notably, the initial formation of tertiary loops in S4 occurred one Carnegie stage later than in S2 or S3. Additionally, the increase in the number of folds and the length per fold in S4 was delayed compared with the number and length of folds observed in both S2 and S3. The number of loops in S1 remained constant (one secondary loop) across all specimens. Upon reaching a critical threshold length, the number of loops exhibited a marked increase, accompanied by rapid elongation in S2, S3, and S4. The number of tertiary loops increased in accordance with the crown-rump length, which exhibited a maximum of 19 tertiary loops in S2 to S4 of the midgut. These findings support the hypothesis that tertiary loops develop biomechanically through the rapid elongation of the midgut and slow growth of the mesentery. This study describes the morphological alterations occurring in the midgut and mesentery over time during the herniated phase of the midgut and provides a comprehensive understanding of the roles of genetic and biomechanical factors in loop formation.