The cecal appendix: one more immune component with a function disturbed by post-industrial culture

Acute appendicitis in children is associated with an abundance of bacteria from the phylum Fusobacteria

BACKGROUND

Although luminal obstruction has traditionally been viewed as the underlying cause of appendicitis, recent evidence has suggested that the disease may result directly from invasion by specific pathogens, e.g. Fusobacterium nucleatum. The purpose of this study was to survey microbial communities within pediatric appendectomy specimens using a culture-independent approach.

METHODS

We performed 16S ribosomal gene sequence analysis to profile the microbiota present within luminal fluid obtained from 22 pediatric appendectomy specimens. These included 10 simple appendicitis cases, 5 perforated appendicitis cases, 2 interval appendectomies, and 5 incidental appendectomies.

RESULTS

Samples could be divided into 2 distinct clusters based upon the composition of the appendiceal bacterial communities. Appendicitis samples contained an increased abundance of Fusobacterium spp. and a reduced abundance of Bacteroides spp. relative to non-appendicitis cases. Appendicitis samples also contained variable amounts of other oral taxa such as Porphyromonas, Parvimonas, and Gemella, whereas these taxa were generally absent from non-appendicitis samples.

CONCLUSIONS

Acute appendicitis is associated with an abundance of Fusobacterium spp. and other pathogens commonly found in the oral cavity. Further research is needed to determine whether these organisms directly cause appendicitis or rather proliferate in the appendix as a secondary consequence of inflammation.

Gut microbial flora, prebiotics, and probiotics in IBD: their current usage and utility

Inflammatory bowel diseases are chronic diseases affecting the gastrointestinal tract, whose major forms are represented by Crohn's disease (CD) and ulcerative colitis (UC). Their etiology is still unclear, although several factors have been identified as major determinants for induction or relapses. Among these, the role of the "forgotten organ", gut microbiota, has become more appreciated in recent years. The delicate symbiotic relationship between the gut microbiota and the host appears to be lost in IBD. In this perspective, several studies have been conducted to assess the role of prebiotics and probiotics in gut microbiota modulation. This is a minireview aimed to address in an easy format (simple questions-simple answers) some common issues about the theme. An update on the role of selected constituents of gut microbiota in the pathogenesis of IBD is presented together with the analysis of the efficacy of gut microbiota modulation by prebiotics and probiotics administration in the management of IBD.

Changes in the length and diameter of the normal appendix throughout childhood

BACKGROUND/AIM

It has been proposed that the narrow diameter of the appendix is important in providing a 'safe zone' for commensal intestinal flora, while the length of the appendix can be variable. This study aimed to investigate the relationship between appendiceal length, diameter and age, in children under the age of eighteen years, to determine if the appendix changes in size with age.

METHODS

The histological records of all cases of children undergoing appendicectomy at the Royal Children's Hospital (Melbourne) between 2009 and 2011 were retrospectively reviewed. Participants were excluded on the basis of histological evidence of acute inflammation, and data on the diameter and length of the appendix were collected from 210 children, aged zero to seventeen years.

RESULTS

Data were stratified by age for analysis into ≤ 3 years, >3 and ≤ 9, >9 and ≤ 13 and >13 years. Mean diameters per group were 3.7 (± 1.3), 6.3 (± 1.2), 6.7 (± 1.6) and 6.9 (± 1.6) millimetres respectively. Mean lengths per group were 39.7 (± 16.1), 66.3 (± 15.3), 63.7 (± 21.3) and 68.8 (± 18.2) millimetres. Both diameter and length were higher in the older age groups, compared with the ≤ 3 year olds (p < 0.001). A positive correlation was seen between age and appendix diameter (R = 0.5, p < 0.001) and length (R = 0.3, p=0.03) in the ≤ 3 group only. Mean diameter and length values did not differ significantly between groups aged > 3 years old.

CONCLUSION

This study showed that following an initial growth period during early infancy up to about 3 years, the appendix achieves its adult proportions and does not continue to grow throughout childhood.

The vermiform appendix: a review

New research on the vermiform appendix has shed light on its function. In further understanding the function of the appendix, this information should not negatively impact the clinical judgment in the event of appendicitis. Although the appendix and its pathology have been noted for centuries, it still presents a challenge in the operating room. The most common emergency surgical procedure performed is an appendectomy. Its highly variable position within the abdomen can cause confusion for clinicians. However, improved imaging modalities have heightened the physician's ability to diagnose disease of this organ. This article reviews germane literature regarding the human vermiform appendix.

Surgery and risk for multiple sclerosis: a systematic review and meta-analysis of case-control studies

BACKGROUND

Although the precise etiology of multiple sclerosis is largely unknown, there is some speculation that a prior history of surgery may be associated with the subsequent risk for developing the disease. Therefore, we aimed to examine surgery as a risk factor for the diagnosis of multiple sclerosis.

METHODS

We searched for observational studies that evaluated the risk for developing multiple sclerosis after surgery that occurred in childhood (≤ 20 years of age) or "premorbid" (> 20 years of age). We specifically included surgeries classified as: tonsillectomy, appendectomy, adenoidectomy, or "surgery". We performed a systematic review and meta-analyses and calculated odds ratios (OR) and their 95% confidence intervals (CIs) using a random effects model.

RESULTS

We identified 33 case-control studies, involving 27,373 multiple sclerosis cases and 211,756 controls. There was a statistically significant association between tonsillectomy (OR = 1.32, 95% CI 1.08-1.61; 12 studies, I(2) = 44%) and appendectomy (OR = 1.16, 95% CI 1.01-1.34; 7 studies, I(2) = 0%) in individual's ≤ 20 years of age and the subsequent risk for developing multiple sclerosis. There was no statistically significant association between risk for multiple sclerosis and tonsillectomy occurring after age 20 (OR = 1.20, 95% CI 0.94-1.53; 9 studies, I(2) = 32%), in those with appendectomy at > 20 years (OR = 1.26, 95% CI 0.92-1.72; 5 studies, I(2) = 46%), and in those with adenoidectomy at ≤ 20 years of age (OR = 1.06, 95% CI 0.68-1.68; 3 studies, I(2) = 35%). The combined OR of 15 studies (N = 2,380) looking at "surgery" before multiple sclerosis diagnosis was not statistically significant (OR = 1.19, 95% CI 0.83-1.70; I(2) = 71%).

CONCLUSIONS

We found a small but statistically significant and clinically important increased risk for developing multiple sclerosis, in those with tonsillectomy and appendectomy at ≤ 20 years of age. There was no convincing evidence to support the association of other surgeries and the risk for multiple sclerosis. Well-designed prospective etiological studies, pertaining to the risk for developing multiple sclerosis, ought to be conducted and should include the examination of various surgeries as risk factors.

Microbial composition of human appendices from patients following appendectomy

The human appendix has historically been considered a vestige of evolutionary development with an unknown function. While limited data are available on the microbial composition of the appendix, it has been postulated that this organ could serve as a microbial reservoir for repopulating the gastrointestinal tract in times of necessity. We aimed to explore the microbial composition of the human appendix, using high-throughput sequencing of the 16S rRNA gene V4 region. Seven patients, 5 to 25 years of age, presenting with symptoms of acute appendicitis were included in this study. Results showed considerable diversity and interindividual variability among the microbial composition of the appendix samples. In general, however, Firmicutes was the dominant phylum, with the majority of additional sequences being assigned at various levels to Proteobacteria, Bacteroidetes, Actinobacteria, and Fusobacteria. Despite the large diversity in the microbiota found within the appendix, however, a few major families and genera were found to comprise the majority of the sequences present. Interestingly, also, certain taxa not generally associated with the human intestine, including the oral pathogens Gemella, Parvimonas, and Fusobacterium, were identified among the appendix samples. The prevalence of genera such as Fusobacterium could also be linked to the severity of inflammation of the organ. We conclude that the human appendix contains a robust and varied microbiota distinct from the microbiotas in other niches within the human microbiome. The microbial composition of the human appendix is subject to extreme variability and comprises a diversity of biota that may play an important, as-yet-unknown role in human health.

There are currently limited data available on the microbial composition of the human appendix. It has been suggested, however, that it may serve as a “safe house” for commensal bacteria that can reinoculate the gut at need. The present study is the first comprehensive view of the microbial composition of the appendix as determined by high-throughput sequencing. We have determined that the human appendix contains a wealth of microbes, including members of 15 phyla. Important information regarding the associated bacterial diversity of the appendix which will help determine the role, if any, the appendix microbiota has in human health is presented.