The gut microbiota composition in patients with right- and left-sided colorectal cancer and after curative colectomy, as analyzed by 16S rRNA gene amplicon sequencing

Background

Gut pathological microbial imbalance or dysbiosis is closely associated with colorectal cancer. Although there are observable differences in molecular and clinical characteristics between patients with right- and left-sided colon cancer, differences in their gut microbiomes have not been thoroughly investigated. Furthermore, subsequent changes in microbiota status after partial colectomy remain unknown. We examined the human gut microbiota composition to determine its relationship with colon cancer and partial colon resection according to location.

Methods

Stool samples from forty-one subjects (10 in the control group, 10 in the right-sided colon cancer [RCC] group, 6 in the sigmoid colon cancer [SCC] group, 9 in the right colon resection [RCR] group and 6 in the sigmoid colon resection [SCR] group) were collected, and DNA was extracted. After terminal restriction fragment length polymorphism (T-RFLP) analysis, the samples were subjected to 16S rRNA gene amplicon sequencing, and the metabolic function of the microbiota was predicted using PICRUSt2.

Results

T-RFLP analysis showed a reduced ratio of clostridial cluster XIVa in the SCC patients and clostridial cluster IX in the RCC patients, although these changes were not evident in the RCR or SCR patients. 16S rRNA gene amplicon sequencing demonstrated that the diversity of the gut microbiota in the RCC group was higher than that in the control group, and the diversity in the SCR group was significantly higher than that in the RCR group. Principal coordinate analysis (PCoA) revealed significant differences according to the group. Analyses of the microbiota revealed that Firmicutes was significantly dominant in the RCC group and that the SCC group had a higher abundance of Verrucomicrobia. At the genus level, linear discriminant analysis effect size (LEfSe) revealed several bacteria, such as Ruminococcaceae, Streptococcaceae, Clostridiaceae, Gemellaceae, and Desulfovibrio, in the RCC group and several oral microbiomes in the SCC group. Metabolic function prediction revealed that cholesterol transport- and metabolism-related enzymes were specifically upregulated in the RCC group and that cobalamin metabolism-related enzymes were downregulated in the SCC group.

Conclusion

Gut microbial properties differ between RCC and SCC patients and between right hemicolectomy and sigmoidectomy patients and may contribute to clinical manifestations.

Second-line triple therapy in failures with vonoprazan-based triple therapy for eradication of Helicobacter pylori

Gastric acid inhibition during treatment is important for the eradication of Helicobacter pylori (H. pylori) infection. A novel potassium-competitive acid blocker, vonoprazan (VPZ), has been demonstrated to achieve high eradication rates; however, the efficacy of second-line treatment in failures of VPZ-based triple therapy has not been well studied. The aim of the current study was to determine the efficacy of VPZ in a first-line regimen for H. pylori eradication, and the efficacy of a second-line regimen using metronidazole (MTZ) in failures with the first-line regimen. Of 580 subjects enrolled in the study, 524 patients completed first-line treatment (275 patients who received VPZ and 249 patients who received LPZ). First-line regimens consisted of a combination of clarithromycin (CAM) 200 or 400 mg twice a day, amoxicillin (AMPC) 750 mg twice a day, and either LPZ 30 mg or VPZ 20 mg twice a day, administered orally for 7 days. CAM and VPZ/LPZ were replaced with metronidazole (MTZ) 250 mg and rabeprazole 10 mg in the second-line regimens. The eradication of H. pylori was assessed by the H. pylori stool antigen test. The overall first-line eradication rate with VPZ was significantly higher than that with LPZ [91.0% (250/275) vs. 84.7% (211/249), respectively, P=0.030]. The dose of CAM (400 vs. 800 mg) did not affect the eradication rate in either the VPZ or LPZ regimens. The overall eradication rates of the second-line regimens with MTZ did not differ significantly between the VPZ-failure and LPZ-failure groups [87.0% (20/23) vs. 87.9% (29/33), respectively, P=0.700]. Therefore, VPZ was significantly more effective than LPZ for first-line treatment. In patients with failure of first-line eradication therapy, successful results of second-line eradication therapy did not differ between the VPZ- and LPZ-failure groups. In conclusion, VPZ-based triple therapy should be recommended for eradication of H. pylori.

A case of a resectable single hepatic epithelioid hemangioendothelioma with characteristic imaging by ADC map

A 47-year-old woman with a single-nodule hepatic tumor was referred to our hospital. She had no symptoms. The tumor was located at the surface of the right lobe of the liver; it showed peripheral low signal intensity on a magnetic resonance imaging apparent diffusion coefficient (ADC) map, and an influx of blood flow into the peripheral area of the tumor at the early vascular phase on perflubutane microbubble (Sonazoid(®)) contrast-enhanced (CE) ultrasonography. Since we suspected a malignant tumor, the patient underwent surgical resection. The hepatic tumor was resected curatively. Pathological examination revealed that the tumor was composed of epithelioid cells with an epithelioid structure and/or cord-like structure. Immunohistochemical staining was positive for cluster of differentiation 34 and factor VIII-related antigen. Based on the above, a final diagnosis of hepatic epithelioid hemangioendothelioma (EHE) was made. Hepatic EHE is a rare hepatic tumor: only a few cases of hepatic EHE with curative resection have been reported. We were unable to reach a diagnosis of hepatic EHE by imaging studies; however, an ADC map was useful in showing the malignant potential of the tumor, and CE ultrasonography was useful in revealing the peripheral blood flow of the tumor. When an unusual hepatic mass is encountered, hepatic EHE should be kept in mind, and the mass should be inspected with more than one imaging modality, including an ADC map, in the process of differential diagnosis.

Diallel cross analysis of body weight in subspecies of mice

A complete 4 x 4 diallel cross of CF#1 (C), C57BL/6NCrj (B) C3H/HeNCrj (H) and Yonakuni wild mice (Y, Mus musculus molossinus yonakuni) has been conducted to estimate the effects of sex, degree of heterosis, general combining ability (gca), specific combining ability (sca), maternal ability, and reciprocal cross on body weight at 1 (Wk1), 3 (Wk3), 6 (Wk6) and 10 (Wk10) weeks of age. A least squares analysis was performed on 828 mice and all sources of variation showed significant effects (P < 0.01) on body weight but not sex at Wk1 (P > 0.05). Males were heavier than females (P < 0.01) at Wk3, Wk6 and Wk10. C and Y were the heaviest and lightest in body weight, whereas H and B were intermediate. Differences in body weight were observed between linebred and linecross at all ages studied: 6.57%, 10.22%, 8.70% and 5.89% heterosis for the respective ages. The degree of gca and maternal effects can be ranked as C > H > B > Y. Crossing between C and H had greater sca than other combinations at all ages studied, whereas B x Y had the smallest. Mean body weight of the offspring from two-line reciprocal cross differed according to their dam. A relatively large proportion of additive genetic effects in contributing to the variation in offspring body weight was indicated.

Prenatal and postnatal maternal effects on body weight in cross-fostering experiment on two subspecies of mice

A cross-fostering experiment was conducted on two quite distinct subspecies of mice, domesticated laboratory mouse of CF#1 (Mus musculus domesticus) and Yonakuni wild mouse (Yk, Mus musculus molossinus yonakuni), to estimate the prenatal and postnatal maternal effects on body weight of offspring. Mating was done between subspecies, two or three females being mated to a male at nine-ten weeks of age. Two dams of different subspecies that littered at the same day were used as a group of foster dams. Litters were standardized to six young mice in order that a dam nursed three mice of her own litter and three mice from that of another subspecies dam. The litters were weaned at 3 weeks of age. The body weight of individual mice was determined at 1, 3, 6 and 10 weeks of age. The result demonstrated that prenatal maternal effects were more important than postnatal maternal effects in contributing to the variation in body weight at all ages examined. Prenatal maternal effects accounted for 61-96% and 35-92% of total variance in males and females, respectively; whereas postnatal effects accounted for 1-7% for males and 3-23% for females. Analysis for between postnatal within prenatal, and between prenatal within postnatal indicated that expression of the body weight of offspring was limited by the genetic type of their prenatal dam and influenced by the postnatal environment of nursing dam. The greatest body weight was attained by offspring born to prenatal CF#1 dams and nursed by postnatal CF#1 dams, followed by CF#1 offspring born to CF#1 dams and nursed by Yk dams, Yk offspring born to Yk dams and nursed by CF#1 dams and the lightest ones were Yk offspring born to Yk dams and nursed by Yk dams.