伊藤 誉

BACKGROUND: The aim of this study was to evaluate the effect of staple height and rectal wall thickness on the development of an anastomotic leak after laparoscopic low anterior resection performed with the double stapling technique. METHODS: One hundred ninety-nine patients treated from 2013 to 2021 were enrolled. Patients were divided into two groups: those who developed an anastomotic leak (AL (+)) and those who did not (AL (-)). Clinicopathological factors were compared between the groups. RESULTS: Anastomotic leaks were observed in 8/199 patients (4%). A 1.5 mm linear stapler was used for 35/199 patients (17%), 1.8 mm for 89 (45%), and 2 mm for 75 (38%). In the AL (+) group (n = 8), lower staple height (1.5 mm or 1.8 mm) was used more frequently than in the AL (-) group (n = 191). Rectal wall thickness and the rectal wall thickness to staple height ratio was significantly (p < .05) greater in the AL (+) group. However, rectal wall thickness was significantly (p < .05) greater in patients who received neoadjuvant treatment and those with advanced T stage (T3,4) lesions. CONCLUSION: Linear stapler staple height and rectal wall thickness are significantly associated with the development of an anastomotic leak after laparoscopic low anterior resection. Larger staples should be selected in patients with a thicker rectal wall due to neoadjuvant treatment or adjacent advanced rectal tumors.

Adenocarcinoma in a Meckel's diverticulum is rare and difficult to diagnose preoperatively. We report the first case of a metachronous Krukenberg tumor from adenocarcinoma in a Meckel's diverticulum. A 45-year-old woman was admitted for recurrent abdominal pain. Computed tomography scan showed a lesion with contrast enhancement, and a Meckel's diverticulum-associated tumor was suspected. Double-ballon enteroscopy revealed intestinal stenosis and biopsy showed adenocarcinoma. Operative findings showed a Meckel's diverticulum with tumor. Histopathological evaluation revealed well-differentiated adenocarcinoma, interrupted by ectopic gastric mucosa, diagnosed as adenocarcinoma in a Meckel's diverticulum. Two years postoperatively, a multi-cystic mass with contrast enhancement was observed in the pelvis on imaging evaluation and oophorectomy performed. Histological examination of the resected ovary showed proliferation of atypical glandular ducts, consistent with metastatic adenocarcinoma. This case demonstrates that adenocarcinoma in a Meckel's diverticulum may result in distant metastases and requires appropriate follow-up.

Pyroptosis is a form of regulated cell death that is characterized by gasdermin processing and increased membrane permeability. Caspase-1 and caspase-11 have been considered to be essential for gasdermin D processing associated with inflammasome activation. In the present study, we found that NLRP3 inflammasome activation induces delayed necrotic cell death via ASC in caspase-1/11-deficient macrophages. Furthermore, ASC-mediated caspase-8 activation and subsequent gasdermin E processing are necessary for caspase-1-independent necrotic cell death. We define this necrotic cell death as incomplete pyroptosis because IL-1β release, a key feature of pyroptosis, is absent, whereas IL-1α release is induced. Notably, unprocessed pro-IL-1β forms a molecular complex to be retained inside pyroptotic cells. Moreover, incomplete pyroptosis accompanied by IL-1α release is observed under the pharmacological inhibition of caspase-1 with VX765. These findings suggest that caspase-1 inhibition during NLRP3 inflammasome activation modulates forms of cell death and permits the release of IL-1α from dying cells.

Long-term peritoneal dialysis (PD) therapy leads to peritoneal inflammation and fibrosis. However, the mechanism underlying PD-related peritoneal inflammation and fibrosis remains unclear. NLRP3 inflammasome regulates the caspase-1-dependent release of interleukin-1β and mediates inflammation in various diseases. Here, we investigated the role of NLRP3 inflammasome in a murine model of PD-related peritoneal fibrosis induced by methylglyoxal (MGO). Inflammasome-related proteins were upregulated in the peritoneum of MGO-treated mice. MGO induced parietal and visceral peritoneal fibrosis in wild-type mice, which was significantly reduced in mice deficient in NLRP3, ASC, and interleukin-1β (IL-1β). ASC deficiency reduced the expression of inflammatory cytokines and fibrotic factors, and the infiltration of macrophages. However, myeloid cell-specific ASC deficiency failed to inhibit MGO-induced peritoneal fibrosis. MGO caused hemorrhagic ascites, fibrin deposition, and plasminogen activator inhibitor-1 upregulation, but all of these manifestations were inhibited by ASC deficiency. Furthermore, in vitro experiments showed that MGO induced cell death via the generation of reactive oxygen species in vascular endothelial cells, which was inhibited by ASC deficiency. Our results showed that endothelial NLRP3 inflammasome contributes to PD-related peritoneal inflammation and fibrosis, and provide new insights into the mechanisms underlying the pathogenesis of this disorder.

要旨：77 歳男性．急性A 型大動脈解離を認め，術前心タンポナーデに伴うショック状態であった．造影CT では，偽腔開存の大動脈解離を認め腹部分枝まで解離が及んでいた．緊急上行大動脈置換術を施行し，術中腸管虚血を疑う所見なく手術を終了した．術後10 時間で下血を認め緊急試験開腹手術を施行した．小腸に虚血を認めず，S 状結腸壊死を認め結腸切除を施行した．帰室後よりアシドーシスの進行と膀胱内圧軽度高値を認め，再度腸管虚血を疑い，2 回目の緊急試験開腹術を施行した．広範な小腸虚血を認めたが，切除範囲が広く切除を断念した．しかし保存的治療で腸管虚血・全身状態の改善を認め退院となった．可逆的な腸管虚血の診断は難しいが，広範な虚血のため虚血部腸管が切除できない症例でもその後虚血が回復することがあり，腸管虚血に対し試験開腹による腹腔内圧の減圧効果が治療に奏功した可能性がある．

Dilatation and curettage (D&C) sometimes causes uterine perforation, which usually does not cause a serious problem. Here, we report uterine perforation caused by D&C, in which the small intestine prolapsed from the uterus, requiring intestinal resection. D&C was performed for missed abortion at 9 weeks. After dilating the cervix, forceps grasped tissue that, upon being pulled, resulted in the intestine being prolapsed into the vagina. Laparotomy revealed a perforation at the low anterior uterine wall, through which the ileum had prolapsed. The mesentery of the prolapsed ileum was completely detached and the ileum was necrotic, which was resected. The uterus and the intestine were reconstructed. Although intestinal prolapse is considered to be caused by "unsafe" D&C performed by inexperienced persons or even by nonphysicians in developing countries, this occurred in a tertiary center of a developed country. We must be aware that adverse events such as uterine perforation with intestinal prolapse can occur even during routine D&C.