舩坂 好平

The new Kyoto guidelines for the management of intraductal papillary mucinous neoplasm (IPMN) provide evidence-based recommendations for the diagnosis and treatment of IPMN. Endoscopic ultrasonography (EUS) is a diagnostic modality with a high spatial resolution that allows detailed observation and obtaining cyst fluid or tissue samples via EUS-guided fine needle aspiration (EUS-FNA). Currently, EUS is an indispensable examination method for the diagnosis of pancreatic diseases. On the other hand, there have been concerns that EUS imaging tends to be highly operator-dependent, and may lack objectivity. Previous guidelines have assigned EUS as an option for patients with worrisome features. However, recent reports indicate that the sensitivity of EUS for the diagnosis of mural nodules (MNs) is more than 90%, comparable or superior to that of contrast-enhanced computed tomography or magnetic resonance cholangiopancreatography. The specific advantages of EUS in the diagnosis of IPMN are: (1) high spatial resolution imaging for the diagnosis of MNs, (2) contrast-enhanced EUS for differentiation of intra-cystic MNs from mucous clots, and (3) pathological diagnosis using EUS-FNA and differential diagnosis of a pancreatic cystic tumor by cystic fluid analysis. In order to utilize EUS in the diagnosis of IPMN, endoscopists are required to have the skills to provide sufficiently objective imaging findings.

Introduction. Hepatocellular carcinoma (HCC) is one of the deadliest cancers worldwide.Gap statement. Monitoring of HCC and predicting its immunotherapy responses are challenging.Aim. This study explored the potential of the gut microbiome for HCC monitoring and predicting HCC immunotherapy responses.Methods. DNA samples were collected from the faeces of 22 patients with HCC treated with atezolizumab/bevacizumab (Atz/Bev) and 85 healthy controls. The gut microbiome was analysed using 16S rRNA next-generation sequencing and quantitative PCR (qPCR).Results. The microbiomes of patients with HCC demonstrated significant enrichment of Lactobacillus, particularly Lactobacillus fermentum, and Streptococcus, notably Streptococcus anginosus. Comparative analysis between Atz/Bev responders (R) and non-responders (NR) revealed a higher abundance of Bacteroides stercoris in the NR group and Bacteroides coprocola in the R group. Using qPCR analysis, we observed elevated levels of S. anginosus and reduced levels of 5α-reductase genes, essential for the synthesis of isoallolithocholic acid, in HCC patients compared to controls. Additionally, the analysis confirmed a significantly lower abundance of B. stercoris in the Atz/Bev R group relative to the NR group.Conclusions. The gut microbiome analysis and specific gene quantification via qPCR could provide a rapid, less invasive, and cost-effective approach for assessing the increased risk of HCC, monitoring patient status, and predicting immunotherapy responses.

Less than half of all patients diagnosed with pancreatic ductal adenocarcinoma (PDAC) respond to chemotherapy, and the prognosis of PDAC is poor, which may be mediated by the gut microbiota. We investigated the clinical improvement effects of 1-kestose, a fructooligosaccharide, on PDAC chemotherapy in this single-center, randomized, controlled pilot trial conducted at Fujita Health University Hospital, which enrolled patients with PDAC. The trial included 1-kestose administration and non-administration groups. The 1-kestose group received 9 g of 1-kestose daily for 12 weeks, and their blood markers, imaging studies, physical findings, and gut microbiota were evaluated. In the 1-kestose administration group, the cancer marker CA19-9 significantly decreased, and there was a reduction in the neutrophil-to-lymphocyte ratio (NLR). There was also suppression of the reduction of albumin levels and of an increase in C-reactive protein. Additionally, Escherichia coli, which typically increases in PDAC, significantly decreased in the 1-kestose group. Thus, 1-kestose altered the gut microbiota and improved the prognostic factors for PDAC. Large-scale, long-term trials of 1-kestose interventions for PDAC are thus warranted to improve the prognosis of PDAC.

The relationship between antitumor response and tumor marker changes was evaluated in patients with advanced hepatocellular carcinoma treated with durvalumab plus tremelimumab (Dur/Tre). Forty patients were enrolled in this retrospective evaluation of treatment outcomes. According to the Response Evaluation Criteria for Solid Tumors version 1.1 at 8 weeks, the objective response (OR) rate was 25% and the disease control (DC) rate was 57.5%. The median alpha-fetoprotein (AFP) ratio at 4 weeks was 0.39 in patients who achieved OR at 8 weeks (8W-OR group), significantly lower than the 1.08 in the non-8W-OR group (p = 0.0068); however, it was 1.22 in patients who did not achieve DC at 8 weeks (non-8W-DC group), significantly higher than the 0.53 in the 8W-DC group (p = 0.0006). Similarly, the median des-γ-carboxy-prothrombin (DCP) ratio at 4 weeks was 0.15 in the 8W-OR group, significantly lower than the 1.46 in the non-8W-OR group (p < 0.0001); however, it was 1.23 in the non-8W-DC group, significantly higher than the 0.49 in the 8W-DC group (p = 0.0215). Early changes in tumor markers after Dur/Tre initiation were associated with antitumor response. In particular, changes in AFP and DCP at 4 weeks may offer useful biomarkers for early prediction of both response and progressive disease following Dur/Tre.

BACKGROUND AND AIMS: Early gastric cancers (EGCs) after Helicobacter pylori (H. pylori) eradication often appear as reddish depressed lesions (RDLs); the same features are also appeared in benign stomachs after eradication. We compared clinic-pathological and endoscopic features of benign and neoplastic RDLs after H. pylori eradication. METHODS: 228 neoplastic RDLs after H. pylori eradication were studied. All lesions were divided into neoplastic RDLs (differentiated carcinoma or adenoma, n=114) and benign RDLs (n=114) according to the histology. Clinical and pathological characteristics were compared in neoplastic and benign groups. Endoscopic diagnostic yields using the white light (WL) endoscopy, chromoendoscopy (CE) using indigo carmine dye and the magnifying endoscopy with narrow-band imaging (ME-NBI) were also evaluated in relation to the pathological diagnosis. RESULTS: Size of neoplastic RDLs was larger than that of benign RDLs (p<0.01). Sensitivity, specificity and accuracy for predicting pathological types of RDLs was 70.1%, 52.6% and 61.4% for the WL, 65.8%, 63.1% and 65.4% for the CE, while the ME-NBI scored better with the 88.6%, 88.6%, 99.1% and 93.9% of sensitivity, specificity and accuracy. The accuracy of the ME-NBI was 99.9% (113/114) in the benign RDLs and 89.4% (101/114) for the neoplastic RDLs. Undiagnosed neoplastic RDLs using the ME-NBI were associated with more differentiated tumors such as adenoma and well-differentiated adenocarcinoma (tub1) and the presence of an unclear demarcation line. CONCLUSIONS: ME-NBI is useful to diagnose RDLs after H. pylori eradiation, while some of neoplastic lesions are difficult to diagnose using the ME-NBI.

Introduction. Colorectal cancer (CRC) is a leading cause of cancer deaths, closely linked to the intestinal microbiota and bile acid metabolism. Secondary bile acids, like deoxycholic and lithocholic acid, are associated with increased CRC risk due to their disruption of vital cellular functions. In contrast, isoallolithocholic acid (isoalloLCA) shows potential health benefits, highlighting the complex role of bile acids in CRC. A specific primer set was previously developed to amplify homologs of the 5α-reductase gene (5ar), which are involved in the biosynthesis of isoalloLCA, thereby enabling the estimation of abundance of 5ar (5ar levels) in the intestine.Hypothesis/Gap Statement. We hypothesized that 5ar levels in the intestine are associated with CRC.Aim. This study aimed to investigate intestinal 5ar levels and compare them across different stages of the adenoma-carcinoma sequence, providing insights into novel strategies for monitoring CRC risk.Methodology. DNA was extracted from intestinal lavage fluids (ILF) collected during 144 colonoscopies. Next-generation sequencing (NGS) was employed to examine the sequence of 5ar homologues, using a specific primer set on DNA from seven selected ILFs - four from carcinoma patients and three from individuals with non-neoplastic mucosa. Additionally, we used quantitative PCR (qPCR) to measure 5ar levels in all 144 DNA samples.Results. We conducted 144 colonoscopies and categorized patients according to the adenoma-cancer sequence: 52 with non-neoplastic mucosa, 69 with adenomas and 23 with carcinoma. Analysis of 292,042 NGS-derived 5ar sequences revealed the seven most prevalent amplicon sequence variants, each 254 base pairs in length. These closely matched or were identical to 5ar sequences in Bacteroides uniformis, Phocaeicola vulgatus and Phocaeicola dorei. Furthermore, qPCR analysis demonstrated significantly lower 5ar levels in the carcinoma group compared to those in the non-neoplastic mucosa group (P = 0.0004). A similar, though not statistically significant, trend was observed in the adenoma group (P = 0.0763), suggesting that 5ar levels decrease as CRC progresses.Conclusion. These findings indicate that PCR-based monitoring of 5ar levels in intestinal samples over time could provide a non-invasive, rapid and cost-effective method for assessing an increased risk of CRC.

Helicobacter pylori induces DNA methylation in gastric mucosa, which links to gastric cancer (GC) risk. In contrast, CpG island methylator phenotype (CIMP) is defined as high levels of cancer-specific methylation and provides distinct molecular and clinicopathological features of GC. The association between those two types of methylation in GC remains unclear. We examined DNA methylation of well-validated H. pylori infection associated genes in GC and its adjacent mucosa and investigated its association with CIMP, various molecular subtypes and clinical features. We studied 50 candidate loci in 24 gastric samples to identify H. pylori infection associated genes. Identified loci were further examined in 624 gastric tissue from 217 primary GC, 217 adjacent mucosa, and 190 mucosae from cancer-free subjects. We identified five genes (IGF2, SLC16A2, SOX11, P2RX7, and MYOD1) as hypermethylated in H. pylori infected gastric mucosa. In non-neoplastic mucosa, methylation of H. pylori infection associated genes was higher in patients with GC than those without. In primary GC tissues, higher methylation of H. pylori infection associated genes correlated with CIMP-positive and its related features, such as MLH1 methylated cases. On the other hand, GC with lower methylation of these genes presented aggressive clinicopathological features including undifferentiated histopathology, advanced stage at diagnosis. H. pylori infection associated DNA methylation is correlated with CIMP, specific molecular and clinicopathological features in GC, supporting its utility as promising biomarker in this tumor type.

BACKGROUND/AIM: The combination of atezolizumab plus bevacizumab (Atz/Bev) has become widely used as a first-line therapy for advanced hepatocellular carcinoma (HCC). However, for post-Atz/Bev therapy, evidence on the outcomes of molecular targeted agents, such as lenvatinib, is limited. The present study aimed to assess the clinical effectiveness of lenvatinib on advanced HCC in patients who had previously undergone Atz/Bev treatment. PATIENTS AND METHODS: Twenty patients with HCC, who received lenvatinib after Atz/Bev treatment, were enrolled in the study. In particular, we examined the impact of adverse events (AEs), such as anorexia and general fatigue. During the treatment, lenvatinib dosages were adjusted or temporarily discontinued in response to AEs. Treatment outcomes were retrospectively evaluated. RESULTS: The objective response rate (ORR) and disease control rate (DCR) for lenvatinib treatment were 25.0% and 95.0%, respectively, according to the Response Evaluation Criteria in Solid Tumors. The median progression-free survival (PFS) was 6.0 months, and the median overall survival (OS) was 10.5 months. Eleven patients experienced anorexia or fatigue, leading to a reduction in the dose of lenvatinib but not to a significant difference in the time to drug discontinuation. Importantly, there were no significant differences between the 11 anorexia/fatigue-suffering patients and the nine other patients with regard to PFS and OS. CONCLUSION: Lenvatinib can be efficacious and safe for treating advanced HCC patients previously treated with Atz/Bev, and AEs such as anorexia and general fatigue can be effectively managed without losing lenvatinib's therapeutic benefits.

BACKGROUND: It has become clear that the intestinal microbiota plays a role in food allergies. The objective of this study was to assess the food allergy-preventive effects of combined intake of a short fructan (1-kestose [Kes]) and a long fructan (inulin ([Inu]) in an ovalbumin (OVA)-induced food allergy mouse model. RESULTS: Oral administration of fructans lowered the allergenic symptom score and alleviated the decreases in rectal temperature and total IgA levels and increases in OVA-specific IgE and IgA levels induced by high-dose OVA challenge, and in particular, combined intake of Kes and Inu significantly suppressed the changes in all these parameters. The expression of the pro-inflammatory cytokine IL-4, which was increased in the allergy model group, was significantly suppressed by fructan administration, and the expression of the anti-inflammatory cytokine IL-10 was significantly increased upon Kes administration. 16 S rRNA amplicon sequencing of the gut microbiota and beta diversity analysis revealed that fructan administration may induce gut microbiota resistance to food allergy sensitization, rather than returning the gut microbiota to a non-sensitized state. The relative abundances of the genera Parabacteroides B 862,066 and Alloprevotella, which were significantly reduced by food allergy sensitization, were restored by fructan administration. In Parabacteroides, the relative abundances of Parabacteroides distasonis, Parabacteroides goldsteinii, and their fructan-degrading glycoside hydrolase family 32 gene copy numbers were increased upon Kes or Inu administration. The concentrations of short-chain fatty acids (acetate and propionate) and lactate were increased by fructan administration, especially significantly in the Kes + Inu, Kes, and Inu-fed (Inu, Kes + Inu) groups. CONCLUSION: Combined intake of Kes and Inu suppressed allergy scores more effectively than single intake, suggesting that Kes and Inu have different allergy-preventive mechanisms. This indicates that the combined intake of these short and long fructans may have an allergy-preventive benefit.

BACKGROUND: Rebleeding after hemostasis of the gastroduodenal ulcer (GDU) is one of the indicators associated with death among GDU patients. However, there are few studies on risk score that contribute to rebleeding after endoscopic hemostasis of bleeding peptic ulcers. AIMS: The aim of this study was to identify factors associated with rebleeding, including patient factors, after endoscopic hemostasis of bleeding gastroduodenal ulcers and to stratify the risk of rebleeding. METHODS: We retrospectively enrolled 587 consecutive patients who were treated for Forrest Ia to IIa bleeding gastroduodenal ulcers with endoscopic hemostasis at three institutions. Risk factors associated with rebleeding were assessed using univariate and multivariate logistic regression analyses. The Rebleeding Nagoya University (Rebleeding-N) scoring system was developed based on the extracted factors. The Rebleeding-N score was internally validated using bootstrap resampling methods. RESULTS: Sixty-four patients (11%) had rebleeding after hemostasis of gastroduodenal ulcers. Multivariate logistic regression analysis revealed four independent rebleeding risk factors: blood transfusion, albumin <2.5, duodenal ulcer, and diameter of the exposed vessel ≧2 mm. Patients with 4 risk factors in the Rebleeding-N score had a 54% rebleeding rate, and patients with 3 risk factors had 44% and 25% rebleeding rates. In the internal validation, the mean area under the curve of the Rebleeding-N score was 0.830 (95% CI = 0.786-0.870). CONCLUSIONS: Rebleeding after clip hemostasis of bleeding gastroduodenal ulcers was associated with blood transfusion, albumin <2.5, diameter of the exposed vessel ≧2 mm, and duodenal ulcer. The Rebleeding-N score was able to stratify the risk of rebleeding.

症例は72歳,男性。年に1度の人間ドックで施行した血液検査にてCA19-9が62.2U/mLと高値であったため,CT検査を行ったところ膵頭部に腫瘍を指摘され,精査加療目的で当院紹介受診となった。腹部造影CT検査で膵頭部に21mm大の乏血性腫瘍を認め膵癌が疑われた。同部位に対して超音波内視鏡下穿刺吸引生検法を施行し,腺癌と病理診断された。以上から膵頭部癌と診断し,手術前化学療法施行後,幽門輪温存膵頭十二指腸切除術を施行した。手術検体の病理組織学的所見では,Hematoxylin Eosin染色で低分化型腺癌成分に加え,小型円形核,淡明な胞体を有する異型に乏しい細胞が蜂巣状に増生しており,免疫染色でsynaptophysin染色,chromogranin染色が共に陽性であったことから,充実胞巣状構造の成分はneuroendocrine neoplasmと診断した。腺癌およびneuroendocrine neoplasmがそれぞれ30%以上存在していたことから膵頭部原発Mixed neuroendocrine-non-neuroendocrine neoplasmと最終診断された。(著者抄録)

症例は72歳,男性。年に1度の人間ドックで施行した血液検査にてCA19-9が62.2U/mLと高値であったため,CT検査を行ったところ膵頭部に腫瘍を指摘され,精査加療目的で当院紹介受診となった。腹部造影CT検査で膵頭部に21mm大の乏血性腫瘍を認め膵癌が疑われた。同部位に対して超音波内視鏡下穿刺吸引生検法を施行し,腺癌と病理診断された。以上から膵頭部癌と診断し,手術前化学療法施行後,幽門輪温存膵頭十二指腸切除術を施行した。手術検体の病理組織学的所見では,Hematoxylin Eosin染色で低分化型腺癌成分に加え,小型円形核,淡明な胞体を有する異型に乏しい細胞が蜂巣状に増生しており,免疫染色でsynaptophysin染色,chromogranin染色が共に陽性であったことから,充実胞巣状構造の成分はneuroendocrine neoplasmと診断した。腺癌およびneuroendocrine neoplasmがそれぞれ30%以上存在していたことから膵頭部原発Mixed neuroendocrine-non-neuroendocrine neoplasmと最終診断された。(著者抄録)

エネルギー産生栄養素とは,たんぱく質,脂質,炭水化物に分類される宿主のエネルギーとして利用される成分である。エネルギー産生栄養素には,体に必要な筋肉,内臓,血管などさまざまな組織の構成成分を供給するとともに,脳をはじめとして生体活動を維持するために日々使用するエネルギーを供給する役割を担っている。さらに,炭水化物の一部は,食物繊維という消化酵素で分解されることなく,大腸に存在する腸内細菌の栄養素として利用される成分を含む。本稿では,エネルギー産生栄養素の代謝の代表的なプロセスを紹介するとともに食物繊維に関し最新の研究動向を紹介する。(著者抄録)

ビタミンとは,三大栄養素などのエネルギー産生栄養素に比べ微量ではあるものの,人体の機能を正常に保つため必要な有機化合物である。ヒトは,三大栄養素を代謝してエネルギー貯蔵分子であるATPに変換する生体内酵素反応において,特定のビタミン(B群,C)やミネラル(鉄,マグネシウム)を必要とする。さらに,ヒトは自ら消化酵素をもたない食物繊維やポリフェノールの代謝を腸内細菌叢に依存し,それが生産するビタミンや短鎖脂肪酸などの低分子代謝物をヒトの代謝に利用している。われわれは,バランスのよい食生活を通じ,自分達の代謝に必要な三大栄養素,ビタミン,ミネラルなどを摂取することはもちろん,腸内細菌の代謝に必要な食物繊維などのプレバイオティクスも摂取する必要がある。(著者抄録)

The combination of atezolizumab plus bevacizumab (Atz/Bev) is now widely used in clinical practice as a first-line treatment for patients with advanced hepatocellular carcinoma (HCC). However, the established regimen for post-treatment after Atz/Bev is unknown. We investigated the efficacy and safety of cabozantinib in patients previously treated with Atz/Bev in real clinical practice, with a focus on whether patients met criteria of Child-Pugh Class A and Eastern Cooperative Oncology Group performance status (ECOG-PS) score 0/1 at baseline. Our results suggest that cabozantinib in patients with advanced HCC previously treated with Atz/Bev can be expected to yield similar outcomes to those seen in the CELESTIAL trial conducted using cabozantinib for post-sorafenib treatment if patients have good liver function and are in good general condition.(1) Background: This study aimed to investigate clinical outcomes for cabozantinib in clinical practice in patients with advanced hepatocellular carcinoma (HCC) previously treated with atezolizumab plus bevacizumab (Atz/Bev), with a focus on whether patients met criteria of Child-Pugh Class A and Eastern Cooperative Oncology Group performance status (ECOG-PS) score 0/1 at baseline. (2) Methods: Eleven patients (57.9%) met the criteria of both Child-Pugh class A and ECOG-PS score 0/1 (CP-A+PS-0/1 group) and eight patients (42.1%) did not (Non-CP-A+PS-0/1 group); efficacy and safety were retrospectively evaluated. (3) Results: Disease control rate was significantly higher in the CP-A+PS-0/1 group (81.1%) than in the non-CP-A+PS-0/1 group (12.5%). Median progression-free survival, overall survival and duration of cabozantinib treatment were significantly longer in the CP-A+PS-0/1 group (3.9 months, 13.4 months, and 8.3 months, respectively) than in the Non-CP-A+PS-0/1 group (1.2 months, 1.7 months, and 0.8 months, respectively). Median daily dose of cabozantinib was significantly higher in the CP-A+PS-0/1 group (22.9 mg/day) than in the non-CP-A+PS-0/1 group (16.9 mg/day). (4) Conclusions: Cabozantinib in patients previously treated with Atz/Bev has potential therapeutic efficacy and safety if patients have good liver function (Child-Pugh A) and are in good general condition (ECOG-PS 0/1).

エネルギー産生栄養素とは,たんぱく質,脂質,炭水化物に分類される宿主のエネルギーとして利用される成分である。エネルギー産生栄養素には,体に必要な筋肉,内臓,血管などさまざまな組織の構成成分を供給するとともに,脳をはじめとして生体活動を維持するために日々使用するエネルギーを供給する役割を担っている。さらに,炭水化物の一部は,食物繊維という消化酵素で分解されることなく,大腸に存在する腸内細菌の栄養素として利用される成分を含む。本稿では,エネルギー産生栄養素の代謝の代表的なプロセスを紹介するとともに食物繊維に関し最新の研究動向を紹介する。(著者抄録)

ビタミンとは,三大栄養素などのエネルギー産生栄養素に比べ微量ではあるものの,人体の機能を正常に保つため必要な有機化合物である。ヒトは,三大栄養素を代謝してエネルギー貯蔵分子であるATPに変換する生体内酵素反応において,特定のビタミン(B群,C)やミネラル(鉄,マグネシウム)を必要とする。さらに,ヒトは自ら消化酵素をもたない食物繊維やポリフェノールの代謝を腸内細菌叢に依存し,それが生産するビタミンや短鎖脂肪酸などの低分子代謝物をヒトの代謝に利用している。われわれは,バランスのよい食生活を通じ,自分達の代謝に必要な三大栄養素,ビタミン,ミネラルなどを摂取することはもちろん,腸内細菌の代謝に必要な食物繊維などのプレバイオティクスも摂取する必要がある。(著者抄録)

Inflammatory myofibroblastic tumor (IMT) is a rare tumor composed of myofibroblasts with inflammatory blood cell infiltration. It commonly occurs in the lungs and rarely in the esophagus. We herein report a valuable case of IMT originating in the esophagus. A 60-year-old Japanese woman with dysphagia had a large subepithelial lesion (SEL) in the cervical esophagus, which was 15 cm in length. Surgical resection was performed to confirm the pathological diagnosis and improve the symptoms. The postoperative diagnosis was IMT composed of multiple nodules. There was no recurrence or metastasis within one year after surgery.

The diagnosis of bile duct tumors can be difficult at times. A transpapillary bile duct biopsy findings with endoscopic retrograde cholangiopancreatography sometimes contradict diagnostic imaging findings. In bile duct tumors, inflammatory polyps in the extrahepatic bile duct are relatively rare with extrahepatic cholangitis. The disease's clinical relevance, including its natural history and prognosis, is not always clear. We show here a rare case of an inflammatory polyp in the common bile duct. A 69-year-old woman with abdominal pain was diagnosed with cholangitis. The findings of contrast-enhanced computed tomography and magnetic resonance cholangiopancreatography suggested that she had extrahepatic cholangiocarcinoma. The examination and therapy of cholangitis were performed by endoscopic retrograde cholangiopancreatography. The cholangiography revealed a suspected tumor in the hilar bile duct with some common bile duct stones. Then, after endoscopic sphincterotomy to remove tiny common bile duct stones, further detailed examinations were performed at the same time using an oral cholangioscope revealed a papillary raised lesion with a somewhat white surface in the bile duct; a biopsy was conducted on the same spot, and epithelial cells with mild atypia appeared in the shape of a papilla. Since the malignant tumor or the intraductal papillary neoplasm of the bile duct could not be ruled out, extrahepatic bile duct resection was conducted with the patient's informed consent. Bile duct inflammatory polyp was the histopathological diagnosis.

次世代シークエンサーをはじめとする難培養性の細菌を解析する研究技術の発展により,腸内細菌叢と疾患の関連性を示す研究が爆発的進歩を遂げている。消化器癌においても例外ではなくそれぞれの癌に特徴的な細菌との関連性が数多く報告されている。本稿では,腸内細菌を研究するうえでの基礎的な研究方法を紹介するとともに消化器癌における腸内細菌叢の影響に関し包括的に述べる。(著者抄録)

次世代シークエンサーをはじめとする難培養性の細菌を解析する研究技術の発展により,腸内細菌叢と疾患の関連性を示す研究が爆発的進歩を遂げている。消化器癌においても例外ではなくそれぞれの癌に特徴的な細菌との関連性が数多く報告されている。本稿では,腸内細菌を研究するうえでの基礎的な研究方法を紹介するとともに消化器癌における腸内細菌叢の影響に関し包括的に述べる。(著者抄録)

Probiotics and prebiotics are viable bacteria with beneficial effects on the host and components that selectively act on the beneficial commensal bacteria, respectively. The combined use of probiotics and prebiotics is termed synbiotics. Probiotic intake improves dysbiosis in the intestinal microbiota and can positively affect canine atopic dermatitis (CAD). However, clinical studies on improvements in CAD using synbiotics remain limited. In this study, 15 dogs with CAD who received prednisolone, a synthetic glucocorticoid (GC) used in the treatment of CAD, for more than 90 days were continuously treated with Lactobacillus paracasei M-1 from fermented food as a probiotic, and trisaccharide kestose as a prebiotic, for 90 days to determine their synbiotic effects on CAD. The CAD symptoms were evaluated using the canine atopic dermatitis lesion index (CADLI) and pruritus visual analog scores (PVAS) at 30, 60 and 90 days after synbiotic administration. The total prednisolone use for 90 days pre- and post-administration was also evaluated. Synbiotic administration significantly reduced the CADLI (pre: median, 28.0 [22.0-32.0]; 30 days: median, 20.0 [20.0-28.0]; 60 days: median, 20.0 [10.0-21.0]; 90 days: median, 12.0 [10.0-19.0]) and PVAS (pre: median, 6.0 [5.0-7.0]; 30 days: median, 3.0 [3.0-3.5]; 60 days: median, 3.0 [3.0-3.5]; 90 days: median, 2.0 [2.0-3.5]) scores, and reduced the total prednisone use over 90 days (pre: 112.0 [25-450] mg; post: 80.0 [18.-300.0] mg; p⟨0.001) in the 15 dogs. Thus, the synbiotic activity of L. paracasei M-1 and trisaccharide kestose can improve CAD.