Appendectomy Is Associated With Alteration of Human Gut Bacterial and Fungal Communities

Environmental and Microbial Factors in Inflammatory Bowel Disease Model Establishment: A Review Partly through Mendelian Randomization

Inflammatory bowel disease (IBD) is a complex condition resulting from environmental, microbial, immunologic, and genetic factors. With the advancement of Mendelian randomization research in IBD, we have gained new insights into the relationship between these factors and IBD. Many animal models of IBD have been developed using different methods, but few studies have attempted to model IBD by combining environmental factors and microbial factors. In this review, we examine how environmental factors and microbial factors affect the development and progression of IBD, and how they interact with each other and with the intestinal microbiota. We also summarize the current methods for creating animal models of IBD and compare their advantages and disadvantages. Based on the latest findings from Mendelian randomization studies on the role of environmental factors in IBD, we discuss which environmental and microbial factors could be used to construct a more realistic and reliable IBD experimental model. We propose that animal models of IBD should consider both environmental and microbial factors to better mimic human IBD pathogenesis and to reveal the underlying mechanisms of IBD at the immune and genetic levels. We highlight the importance of environmental and microbial factors in IBD pathogenesis and offer new perspectives and suggestions for improving experimental animal modeling. Our goal is to create a model that closely resembles the clinical picture of IBD.

Beyond a vestigial organ: effects of the appendix on gut microbiome and colorectal cancer

The role of appendectomy in the pathogenesis of colorectal cancer (CRC) is a recent topic of contention. Given that appendectomy remains one of the most commonly performed operations and a first-line management strategy of acute appendicitis, it is inherently crucial to elucidate the association between prior appendectomy and subsequent development of CRC, as there may be long-term health repercussions. In this review, we summarize the data behind the relationship of CRC in post-appendectomy patients, discuss the role of the microbiome in relation to appendectomy and CRC pathogenesis, and provide an appraisal of our current understanding of the function of the appendix. We seek to piece together the current landscape surrounding the microbiome and immunological changes in the colon post-appendectomy and suggest a direction for future research involving molecular, transcriptomic, and immunologic analysis to complement our current understanding of the alterations in gut microbiome.

Is there a link between appendicitis and the risk of diverticular disease?: a large German cohort study

PURPOSE

Appendicitis, characterized by inflammation of the vermiform appendix, is a common abdominal emergency necessitating appendectomy. Recent evidence suggests a potential link between appendicitis and subsequent diverticular disease, yet population-based studies investigating this association are limited.

METHODS

Utilizing the Disease Analyzer database encompassing data from over 1000 primary care practices in Germany, we conducted a retrospective cohort study. We included 25,379 adults diagnosed with appendicitis and an equal number of matched controls without appendicitis. The incidence of diverticular disease over a 10-year follow-up period was compared between the two cohorts. Cox regression analysis was performed to assess the association between appendicitis and diverticular disease, adjusting for potential confounders.

RESULTS

Our findings revealed a significant association between appendicitis and subsequent diverticular disease (HR: 1.76; 95% CI: 1.57-1.97), with an increased risk observed across all age groups. Notably, this association was stronger in men (HR: 2.00; 95% CI: 1.68-2.37) than in women (HR: 1.58; 95% CI: 1.36-1.84). The cumulative 10-year incidence of diverticular disease was higher in patients with appendicitis (6.5%) compared to those without (3.6%). Additionally, we observed a clear age-dependent increase in the incidence of diverticular disease.

CONCLUSION

This large-scale population-based study provides valuable insights into the interaction between appendicitis and diverticular disease. The study underscores the need for further research elucidating the underlying mechanisms linking appendicitis to diverticular disease. Probiotics emerge as a potential therapeutic avenue warranting exploration in the management of both conditions. These findings have important implications for clinical practice, highlighting the importance of considering appendicitis as a potential risk factor for diverticular disease, particularly in men. Further investigation is warranted to validate these findings and explore potential therapeutic interventions targeting the shared pathophysiological pathways underlying both conditions.

Gut microbiota modulate CD8+ T cell immunity in gastric cancer through Butyrate/GPR109A/HOPX

The gut microbiota and Short-chain fatty acids (SCFAs) can influence the progression of diseases, yet the role of these factors on gastric cancer (GC) remains uncertain. In this work, the analysis of the gut microbiota composition and SCFA content in the blood and feces of both healthy individuals and GC patients indicated that significant reductions in the abundance of intestinal bacteria involved in SCFA production were observed in GC patients compared with the controls. ABX mice transplanted with fecal microbiota from GC patients developed more tumors during the induction of GC and had lower levels of butyric acid. Supplementation of butyrate during the induction of gastric cancer along with H. pylori and N-methyl-N-nitrosourea (MNU) in WT in GPR109A-/-mice resulted in fewer tumors and more IFN-γ+ CD8+ T cells, but this effect was significantly weakened after knockout of GPR109A. Furthermore, In vitro GC cells and co-cultured CD8+ T cells or CAR-Claudin 18.2+ CD8+ T cells, as well as in vivo tumor-bearing studies, have indicated that butyrate enhanced the killing function of CD8+ T cells or CAR-Claudin 18.2+ CD8+ T cells against GC cells through G protein-coupled receptor 109A (GPR109A) and homologous domain protein homologous box (HOPX). Together, these data highlighted that the restoration of gut microbial butyrate enhanced CD8+ T cell cytotoxicity via GPR109A/HOPX, thus inhibiting GC carcinogenesis, which suggests a novel theoretical foundation for GC management against GC.

Appendectomy in Management of Malrotation of Gut is it Necessary?

Introduction

Malrotation is a congenital anatomical anomaly that affects the normal positioning of the intestines. Traditional management of malrotation, as described by Ladd, consists of detorsion of the volvulus if present, division of Ladd's bands, widening of the mesenteric root, proper positioning of the small and large bowels, and a prophylactic appendectomy. This study was done to determine whether appendectomy should be an integral part of the Ladds procedure or if it can be avoided.

Materials and Methods

This retrospective observational study was conducted in one pediatric surgical unit in the tertiary care center of North India. All the cases of malrotation of the gut managed from January 2008 to December 2018 were reviewed. The details of the patients were recovered from the electronic data recording system of the hospital and manual operation theater records. The cases that have a follow-up of <5 years were not included in the study. The details were charted in an Excel Sheet for the analysis. No statistical test was performed because there was no event in patients in whom prophylactic appendectomy was not done.

Results

The data analysis revealed that a total of 66 malrotation patients were managed during this period, those who fulfilled the inclusion criteria. Among 66 cases included in the study, in 41 cases, prophylactic appendectomy was done, whereas in the rest 25, prophylactic appendectomy was not done. During the follow-up, none of the patients in whom the appendix was preserved presented with signs or symptoms related to appendicitis or any other complications.

Conclusion

Ladds procedure without appendectomy can be performed in view of the potential use of the appendix in the future, and with the fact that in the current era of advanced medicine, appendicitis can be diagnosed early due to the advancement of imaging and better record keeping.

The appendix and ulcerative colitis - an unsolved connection

The appendix is thought to have a role in the pathogenesis of ulcerative colitis, but the nature and basis of this association remains unclear. In this Perspective, we consider the biology of the appendix with respect to its immunological function and the microbiome, and how this relates to evidence that supports the involvement of the appendix in ulcerative colitis. In experimental models, removal of the inflamed appendix prevents colitis, and in human observational studies, appendectomy is associated with protection against ulcerative colitis. Further, among people who develop ulcerative colitis, appendectomy before diagnosis might influence the course and outcomes of the disease - some evidence suggests that it protects against colectomy but could increase the risk of colorectal cancer. Appendectomy after onset of ulcerative colitis seems to have disparate consequences. Clinical trials to understand whether appendectomy has a role in the treatment of ulcerative colitis are ongoing. Major questions about the role of the appendix in the pathogenesis of ulcerative colitis remain unanswered, and further research is needed to establish whether the connection is clinically relevant.

Probiotics, the Immune Response and Acute Appendicitis: A Review

Acute appendicitis is a common reason for admission to the Emergency Department (ED). It affects almost 70% of people under 30 years of age and 10% over 60 years of age. Its diagnosis includes the combination of clinical signs, laboratory tests and imaging. For years, surgical appendectomy has been the first-line therapy for acute appendicitis, but currently the management has shown some changes, in particular in patients with uncomplicated appendicitis. Recent studies have investigated the use of probiotics as an adjunctive therapy with promising results in conferring health benefits to patients with acute appendicitis. The aim of our review is to summarize the results of clinical studies about probiotics and the immunological response in acute appendicitis, discussing the limitations and future directions of this research.

Capsulized Fecal Microbiota Transplantation Induces Remission in Patients with Ulcerative Colitis by Gut Microbial Colonization and Metabolite Regulation

Fecal microbiota transplantation (FMT) can induce clinical remission in ulcerative colitis (UC) patients. Enemas, nasoduodenal tubes, and colonoscopies are the most common routes for FMT administration. However, there is a lack of definitive evidence regarding the effectiveness of capsulized FMT treatment in UC patients. In this study, we administered capsulized FMT to 22 patients with active UC to assess the efficiency of capsulized FMT and determine the specific bacteria and metabolite factors associated with the response to clinical remission. Our results showed that the use of capsulized FMT was successful in the treatment of UC patients. Capsulized FMT induced clinical remission and clinical response in 57.1% (12 of 21) and 76.2% (16 of 21) of UC patients, respectively. Gut bacterial richness was increased after FMT in patients who achieved remission. Patients in remission after FMT exhibited enrichment of Alistipes sp. and Odoribacter splanchnicus, along with increased levels of indolelactic acid. Patients who did not achieve remission exhibited enrichment of Escherichia coli and Klebsiella and increased levels of biosynthesis of 12,13-DiHOME (12,13-dihydroxy-9Z-octadecenoic acid) and lipopolysaccharides. Furthermore, we identified a relationship between specific bacteria and metabolites and the induction of remission in patients. These findings may provide new insights into FMT in UC treatment and provide reference information about therapeutic microbial manipulation of FMT to enhance its effects. (This study has been registered at ClinicalTrails.gov under registration no. NCT03426683). IMPORTANCE Fecal microbiota transplantation has been successfully used in patients. Recently, capsulized FMT was reported to induce a response in patients with UC. However, limited patients were enrolled in such studies, and the functional factors of capsulized FMT have not been reported in the remission of patients with UC. In this study, we prospectively recruited patients with UC to receive capsulized FMT. First, we found that capsulized FMT could induce clinical remission in 57.1% of patients and clinical response in 76.2% after 12 weeks, which was more acceptable. Second, we found a relationship between the decrease of opportunistic pathogen and lipopolysaccharide synthesis in patients in remission after capsulized FMT. We also identified an association between specific bacteria and metabolites and remission induction in patients after capsulized FMT. These findings put forward a possibility for patients to receive FMT at home and provide reference information about therapeutic microbial manipulation of FMT to enhance its effects.

Association of the Bacteria of the Vermiform Appendix and the Peritoneal Cavity with Complicated Acute Appendicitis in Children

BACKGROUND

Primary infection has been questioned as the pathogenetic cause of acute appendicitis. We attempted to identify the bacteria involved and to investigate if their species, types, or combinations affected the severity of acute appendicitis in children.

METHODS

Samples from both the appendiceal lumen and the peritoneal cavity of 72 children who underwent appendectomy were collected to perform bacterial culture analysis. The outcomes were studied to identify if and how they were associated with the severity of the disease. Regression analysis was performed to identify any risk factors associated with complicated appendicitis.

RESULTS

Escherichia coli, Pseudomonas aeruginosa, and Streptococcus species were the most common pathogens found in the study population. The same microorganisms, either combined or separate, were the most common in the appendiceal lumen and the peritoneal cavity of patients with complicated appendicitis. Gram-negative bacteria and polymicrobial cultures in the peritoneal fluid and in the appendiceal lumen were associated with complicated appendicitis. Polymicrobial cultures in the peritoneal cavity presented a four times higher risk of complicated appendicitis.

CONCLUSIONS

Polymicrobial presentation and Gram-negative bacteria are associated with complicated appendicitis. Antibiotic regimens should target the combinations of the most frequently identified pathogens, speculating the value of early antipseudomonal intervention.

Appendectomy as part of Ladd's procedure: a systematic review and survey analysis

BACKGROUND

Ladd's Procedure has been the surgical intervention of choice in the management of congenital intestinal malrotation for the past century. Historically, the procedure included performing an appendectomy to prevent future misdiagnosis of appendicitis, since the location of the appendix will be shifted to the left side of the abdomen. This study consists of two parts. A review of the available literature on appendectomy as part of Ladd's procedure and then a survey sent to pediatric surgeons about their approach (to remove the appendix or not) while performing a Ladd's procedure and the clinical reasoning behind their approach.

METHODS

The study consists of 2 parts: (1) a systematic review was performed to extract articles that fulfill the inclusion criteria; (2) a short online survey was designed and sent by email to 168 pediatric surgeons. The questions in the survey were centered on whether a surgeon performs an appendectomy as part of the Ladd's procedure or not, as well as their reasoning behind either choice.

RESULTS

The literature search yielded five articles, the data from the available literature are inconsistent with performing appendectomy as part of Ladd's procedure. The challenge of leaving the appendix in place has been briefly described with minimal to no focus on the clinical reasoning. The survey demonstrated that 102 responses were received (60% response rate). Ninety pediatric surgeons stated performing an appendectomy as part of the procedure (88%). Only 12% of pediatric surgeons are not performing appendectomy during Ladd's procedure.

CONCLUSION

It is difficult to implement a modification in a successful procedure like Ladd's procedure. The majority of pediatric surgeons perform an appendectomy as part of its original description. This study has identified gaps in the literature pertaining to analyze the outcomes of performing Ladd's procedure without an appendectomy which should be explored in future research.

Risk of colorectal cancer after appendectomy: A systematic review and meta-analysis

BACKGROUND AND AIM

Appendectomy is associated with various diseases, but whether it increases the risk of colorectal cancer (CRC) remains uncertain. We conducted a systematic review and meta-analysis aimed at investigating the suggested correlation between appendectomy and CRC.

METHODS

Systematic retrieval was performed using the PubMed, Embase, Cochrane library, Web of Science, and ClinicalTrials.gov databases up to May 4, 2022, for studies reported the influence of appendectomy on CRC, colon cancer (CC) or rectal cancer (RC). Odd ratios (ORs) and 95% confidence intervals (CIs) of CRC after appendectomy were pooled using the random effects model. Subgroup analyses were carried on by region, sex, and tumor location.

RESULTS

Our search identified 1743 articles, of which 22 studies from three continents published between 1964 and 2022 were eligible for inclusion. Overall, people with appendectomy had a higher risk of CRC (OR = 1.31; 95% CI [1.05, 1.62]). But the risk for Europeans was not significant (OR = 0.94; 95% CI [0.87, 1.02]; I²  = 0%), while for Americans and Asians, appendectomy would increase the risk of CRC (OR = 1.68; 95% CI [1.15, 2.44]; I²  = 65% and OR = 1.46; 95% CI [1.04, 2.05]; I²  = 98%), especially in females and in developing countries. It is worth noting that appendectomy might be a protective factor for CC in European women (OR = 0.87; 95% CI [0.77, 0.98]; I²  = 0%).

CONCLUSIONS

Appendectomy may be a risk factor for CRC, with varying degrees in different populations. More high-quality cross-regional studies are needed for better clinical decision making.

Disturbed Pediatric Gut Microbiome Maturation in the Developmental Origins of Subsequent Chronic Disease

The microbiome is known to play an important role in the development and maintenance of human health. During early childhood the gut microbiome undergoes a rapid evolution, making this developmental window most susceptible to microbial manipulation and, therefore, most vulnerable to environmental stimuli. Such stimuli may induce persistent alterations (or dysbiosis) in microbiome and/or host physiology, thereby resulting in susceptibility to subsequent disease development. This phenomenon is frequently described as "the microbial developmental origins of disease." In this topic of the month, we call attention to the microbial developmental origins of disease by examining the potential for childhood antibiotic exposures and appendectomy (ie, inducers of dysbiosis) to influence the pathogenesis of certain multifactorial, common diseases (eg, celiac disease, inflammatory bowel disease, obesity), especially those with increasing incidence worldwide. We conclude that fully appreciating the critical components in the microbial developmental origins of common chronic disorders is a major task ahead of pediatric gastroenterologists in the 21st century. Such information will be key in working to prevent numerous common and emerging disorders.

Colonic drug delivery: Formulating the next generation of colon-targeted therapeutics

Colonic drug delivery can facilitate access to unique therapeutic targets and has the potential to enhance drug bioavailability whilst reducing off-target effects. Delivering drugs to the colon requires considered formulation development, as both oral and rectal dosage forms can encounter challenges if the colon's distinct physiological environment is not appreciated. As the therapeutic opportunities surrounding colonic drug delivery multiply, the success of novel pharmaceuticals lies in their design. This review provides a modern insight into the key parameters determining the effective design and development of colon-targeted medicines. Influential physiological features governing the release, dissolution, stability, and absorption of drugs in the colon are first discussed, followed by an overview of the most reliable colon-targeted formulation strategies. Finally, the most appropriate in vitro, in vivo, and in silico preclinical investigations are presented, with the goal of inspiring strategic development of new colon-targeted therapeutics.

Non-operative management of acute appendicitis in children

Appendicitis is one of the most common surgical emergencies in children and adults. Appendectomy as the standard care has been challenged in the recent years with growing evidence about non-operative treatment as a potential primary treatment in patients presenting with signs and symptoms suggestive of acute appendicitis. This review aims to establish where the recent research stands regarding conservative treatment of acute appendicitis, especially in children. There are several studies that report the potential safety and efficacy of treating acute appendicitis non-operatively. Several studies have challenged the concept of acute appendicitis being a progressive disease that always ends in perforation, rather than a disease that can present as different forms with only a defined number of cases progressing to perforation. The lack of randomized controlled studies is a limitation and well-designed randomized controlled trials are needed to determine the role of non-operative management of acute appendicitis in children.

The vermiform cecal appendix, expendable or essential? A narrative review

PURPOSE OF REVIEW

The vermiform cecal appendix is a small thin pouch-like tube of intestinal tissue situated in the lower right abdomen. It is attached at the junction of the large intestine between the ascending colon and small intestine. Historically, the appendix has been labeled redundant with no significant function, a remnant of evolution. This idea was thought to represent a function that may have been critical for survival that became nonsignificant over time. Evolutionary biologists deemed it to be a vestigial organ that early in human evolution was a dedicated organ that was useful and exploited by herbivorous ancestors.

RECENT FINDINGS

Currently, the vermiform cecal appendix has generated significant renewed research interest. As such it has been reported to present a site with a high concentration of lymphoid tissue and a biofilm microbiome that approximately mirrors that which is found in the large bowel.

SUMMARY

Research suggests that the vermiform cecal appendix may be the site of a safe-house biofilm that could re-inoculate the large bowel. Given that the appendix has no known role in digestion, the network of lymphoid tissue and microbiome could constitute an initial site of bacterial translocations that can influence early life ontology and immunological tolerance. A dysbiotic microbiome in the appendix is posited to trigger inflammatory sequelae.

Endoscopic retrograde appendicitis therapy (ERAT) vs appendectomy for acute uncomplicated appendicitis: A prospective multicenter randomized clinical trial

OBJECTIVE

To compare the efficacy and feasibility of endoscopic retrograde appendicitis therapy (ERAT) with appendectomy for treating acute uncomplicated appendicitis.

METHODS

This was a prospective multicenter randomized trial in which consecutive patients were randomized at a ratio of 1:1 to receive either ERAT or appendectomy. The outcomes included technical success rate, procedure time, postoperative pain relief, postoperative analgesic use, time to soft diet intake, length of postoperative hospital stay, postoperative complications, and recurrence rate.

RESULTS

From August 2013 to December 2015, 110 patients with acute uncomplicated appendicitis were randomized to ERAT or appendectomy. The technical success rate was 94.55% for ERAT compared with 100% for appendectomy. Recurrence of appendicitis within 3-year follow-up occurred in 8 patients following ERAT. Postoperative abdominal pain was less frequent with ERAT than with appendectomy (21.15% [11/52] vs 87.27% [48/55], P < 0.001). Soft diet intake begun earlier after ERAT than appendectomy (6 h vs 48 h, P < 0.001), and post-procedure hospital stay was shorter (3 days vs 5 days, P < 0.001), as was the use of analgesics postoperatively (9.09% vs 49.09%, P < 0.001).

CONCLUSIONS

ERAT is a feasible, safe, and effective alternative approach for the management of acute uncomplicated appendicitis. Compared with appendectomy, advantages of ERAT include no skin wound, organ preservation, reduced postoperative pain, early food intake, quick recovery, fewer postoperative complications, and shorter post-procedure hospitalization. The unsolved problem related to ERAT is the recurrence of appendicitis.

The Absence of STING Ameliorates Non-Alcoholic Fatty Liver Disease and Reforms Gut Bacterial Community

Non-alcoholic fatty liver disease (NAFLD) is one of the primary causes of cirrhosis and a major risk factor for hepatocellular carcinoma and liver-related death. It has been correlated with changes in the gut microbiota, which promote its development by regulating insulin resistance, bile acid and choline metabolism, and inflammation. Recent studies suggested a controversial role of the stimulator of interferon genes (STING) in the development of NAFLD. Here, we showed that as an immune regulator, STING aggravates the progression of NAFLD in diet-induced mice and correlated it with the changes in hepatic lipid metabolism and gut microbiota diversity. After feeding wild-type (WT) and STING deletion mice with a normal control diet (NCD) or a high-fat diet (HFD), the STING deletion mice showed decreased lipid accumulation and liver inflammation compared with WT mice fed the same diet. In addition, STING specifically produced this hepatoprotective effect by inhibiting the activation of CD8+ T cells. The gut microbiota analysis revealed significant differences in intestinal bacteria between STING deletion mice and WT mice under the same diet and environmental conditions; moreover, differential bacterial genera were associated with altered metabolic phenotypes and involved in related metabolic pathways. Overall, our findings reveal the important regulatory role that STING plays in the progression of NAFLD. In addition, the change in intestinal microbiota diversity may be the contributing factor.