Related Experiment Video
Updated: Aug 11, 2025
Microsatellite DNA Genotyping and Flow Cytometry Ploidy Analyses of Formalin-fixed Paraffin-embedded Hydatidiform Molar Tissues
Published on: October 20, 2019
Detection of Enterobius vermicularis in archived formalin-fixed paraffin-embedded (FFPE) appendectomy blocks: It's
Maryam Haghshenas1, Mona Koosha2, Alireza Latifi1
1Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Abstract:
Acute appendicitis represents one of the most common causes of emergency abdominal surgery worldwide. Meanwhile, Enterobius vermicularis has been suggested as one of the probable causes of appendicitis. In this study, the morphological characteristics of the remnant pinworms and pathologic changes were explored in old-archived FFPE tissues of appendectomies. Moreover, we provide the first molecular identification, genetic, and haplotype variation of this nematode from the old-archived FFPE tissue section of appendectomy using the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. Seventeen FFPE appendectomies with E. vermicularis infection, stored over 12-22 years, were collected from two different geographical areas of Iran. In the histopathological examination, tissue changes were observed in thirteen cases (76.4%) and inflammation in four blocks (23.5%). After DNA extraction, the cox1 gene was amplified in twelve (70.6%) cases using the nested polymerase chain reaction (PCR). Phylogenetic analysis and a median-joining network of 78 available cox1 sequences of E. vermicularis revealed 59 haplotypes. We identified five haplotypes that fell into type B. All Haplotypes are novel except for two haplotypes, Hap32 and Hap37, identical to E. vermicularis sequences from Iran, Greece, and Germany. The ranges of diversity distance and haplotype diversity within the isolates were 0-1.9% and HD:0.643-0.667, subsequently. Overall, the absence of inflammation or even tissue changes in some sections can suggest the possible non-inflammatory role of E. vermicularis in appendicitis. Although FFPE material suffers from PCR inhibition, we could successfully use nested PCR to characterize E. vermicularis in old-archived appendectomy blocks and suggest this method as a complementary diagnosis technique in pathology. While the predominant type was B in the Middle East and Europe, further studies on a larger sample size from different geographical regions could probably confirm the results obtained in the present study.
Insights
Enterobius vermicularis pinworms may cause appendicitis without inflammation. This study identified novel genetic variations in archived appendectomy tissues using molecular methods, suggesting a complementary diagnostic approach.
Area of Science:
- Medical Parasitology
- Molecular Diagnostics
- Gastrointestinal Pathology
Background:
- Acute appendicitis is a common surgical emergency.
- Enterobius vermicularis (pinworm) infection is a suspected, though not fully understood, cause of appendicitis.
- Limited data exists on the role of pinworms in appendicitis pathology and genetics.
Purpose of the Study:
- To investigate morphological and pathological changes associated with Enterobius vermicularis in archived appendectomy tissues.
- To perform molecular identification and genetic/haplotype variation analysis of E. vermicularis from old Formalin-Fixed Paraffin-Embedded (FFPE) tissues.
- To explore the potential non-inflammatory role of E. vermicularis in appendicitis.
Main Methods:
- Retrospective analysis of 17 FFPE appendectomy samples with E. vermicularis infection (12-22 years old).
- Histopathological examination for tissue changes and inflammation.
- DNA extraction from FFPE tissues, followed by nested Polymerase Chain Reaction (PCR) amplification of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene.
- Phylogenetic analysis and median-joining network construction using available E. vermicularis cox1 sequences.
Main Results:
- Histopathology revealed tissue changes in 76.4% and inflammation in 23.5% of cases.
- The cox1 gene was successfully amplified in 70.6% of samples using nested PCR.
- Phylogenetic analysis identified 59 haplotypes among 78 E. vermicularis cox1 sequences, with five novel haplotypes identified in this study.
- The predominant haplotype type identified was B, consistent with previous findings in the Middle East and Europe.
- Absence of inflammation or tissue changes in some cases suggests a potential non-inflammatory role for E. vermicularis.
Conclusions:
- Nested PCR is effective for molecular characterization of E. vermicularis in old FFPE appendectomy tissues, serving as a complementary diagnostic tool.
- The findings suggest that E. vermicularis may contribute to appendicitis through non-inflammatory mechanisms.
- Further large-scale studies across diverse geographical regions are recommended to validate these findings and confirm haplotype prevalence.
