Project description:Appendicitis is the most common condition necessitating emergency abdominal surgery. While most cases are localized, 20% are complicated and result in appendix perforation. The management of non-complicated appendicitis varies across different medical centers, encompassing both surgical and non-surgical options, whereas complicated appendicitis is predominantly managed surgically. Differentiating them poses a clinical challenge, especially in pediatric patients, crucial for guiding appropriate treatment strategies. Therefore, there is an unmet need for biomarkers to distinguish the two entities. Here we examined the utility of epigenetic liquid biopsies in appendicitis. We used DNA methylation markers specific to immune and gastrointestinal epithelial cells to assess the tissue origins of plasma cell-free DNA (cfDNA) in patients with appendicitis. Appendix epithelium cfDNA was not detected in plasma samples from children with appendicitis relative to patients with abdominal pain and controls. In contrast, neutrophil and regulatory T-cell cfDNA were elevated in appendicitis enhancing the specificity and sensitivity of appendicitis diagnosis beyond the information provided by neutrophil counts. Notably, eosinophil cfDNA was most significantly elevated in children with perforated compared with non-perforated appendicitis. This finding was cross-validated using a machine-learning approach. In conclusion, eosinophil cfDNA can serve as a non-invasive biomarker for diagnosing perforated appendicitis.
Project description:Background: The diagnosis of acute appendicitis can be surprisingly difficult without computed tomography, which carries significant radiation exposure. Genome-wide expression profiling was applied to whole blood RNA of acute appendicitis patients versus patients with other abdominal disorders, in order to identify biomarkers of appendicitis. From a large cohort of emergency patients, a discovery set of patients with surgically confirmed appendicitis, or abdominal pain from other causes, was identified. RNA from whole blood was profiled by microarrays, and RNA levels were filtered by a combined fold-change (>2) and p value (<0.05). A separate set of patients, including patients with respiratory infections, was used to validate a partial least squares discriminant (PLSD) prediction model. Results: Transcript profiling identified 37 differentially expressed genes (DEG) in appendicitis versus abdominal pain patients. The DEG list contained 3 major ontologies: infection-related, inflammation-related, and ribosomal processing. Appendicitis patients had lower level of neutrophil defensin mRNA (DEFA1,3), but higher levels of alkaline phosphatase (ALPL) and interleukin-8 receptor-ß (IL8RB), which was confirmed in a larger cohort of 60 patients using droplet digital PCR (ddPCR). Conclusions: Patients with acute appendicitis have detectable changes in the mRNA expression levels of factors related to neutrophil inate defense systems. The low defensin mRNA levels suggest that appendicitis patient's immune cells are not directly activated by pathogens, but are primed by diffusible factors in the microenvironment of the infection. The detected biomarkers are consistent with prior evidence that biofilm-forming bacteria in the appendix may be an important factor in appendicitis.
Project description:Gene expression was evaluated in 9 appendix samples removed from patients who went to the operating room with the diagnosis of acute appendicitis and 4 samples removed for non-inflammatory reasons. A circumferential piece of tissue was obtained at the distal aspect of each specimen. The tissue was flash frozen at -80 degrees for later processing. Frozen specimens were homogenized into TriReagent and RNA was isolated according to the manufacturer's instruction. RNA was processed and hybridized to Affymetrix microarray. Keywords: Disease state analysis
Project description:Gene expression was evaluated in 9 appendix samples removed from patients who went to the operating room with the diagnosis of acute appendicitis and 4 samples removed for non-inflammatory reasons. A circumferential piece of tissue was obtained at the distal aspect of each specimen. The tissue was flash frozen at -80 degrees for later processing. Frozen specimens were homogenized into TriReagent and RNA was isolated according to the manufacturerâs instruction. RNA was processed and hybridized to Affymetrix microarray. Experiment Overall Design: 9 patients and 4 controls
Project description:The gut microbiome can impact brain health and is altered in Parkinson’s disease (PD) patients. The vermiform appendix is a lymphoid tissue implicated in the storage and regulation of the gut microbiome. Here, we investigate changes in the functional microbiome in the appendix of PD patients relative to controls by metatranscriptomic analysis. In the PD appendix, we find microbial dysbiosis affecting lipid metabolism, particularly an upregulation of bacteria responsible for secondary bile acid synthesis. Likewise, proteomic and transcript analysis in the PD gut corroborates a disruption in cholesterol homeostasis and lipid catabolism. Bile acid analysis in the PD appendix reveals an increase in the microbially-derived, toxic secondary bile acids deoxycholic acid (DCA) and lithocholic acid (LCA). Synucleinopathy in mice induces similar microbiome alterations to those of PD patients and heightens microbial changes to gut inflammation. As observed in PD, the mouse model of synucleinopathy has elevated DCA and LCA. Raised levels of DCA and LCA can lead to liver injury, and an analysis of blood markers of liver dysfunction shows evidence of biliary abnormalities in PD patients, including elevated alkaline phosphatase and bilirubin. Increased bilirubin levels are also evident before PD diagnosis, in individuals at-risk of developing PD. In sum, microbially-derived toxic bile acids are heightened in PD and biliary changes may even precede the onset of overt motor symptoms.
Project description:The gut microbiome can impact brain health and is altered in Parkinson’s disease (PD) patients. The vermiform appendix is a lymphoid tissue implicated in the storage and regulation of the gut microbiome. Here, we investigate changes in the functional microbiome in the appendix of PD patients relative to controls by metatranscriptomic analysis. In the PD appendix, we find microbial dysbiosis affecting lipid metabolism, particularly an upregulation of bacteria responsible for secondary bile acid synthesis. Likewise, proteomic and transcript analysis in the PD gut corroborates a disruption in cholesterol homeostasis and lipid catabolism. Bile acid analysis in the PD appendix reveals an increase in the microbially-derived, toxic secondary bile acids deoxycholic acid (DCA) and lithocholic acid (LCA). Synucleinopathy in mice induces similar microbiome alterations to those of PD patients and heightens microbial changes to gut inflammation. As observed in PD, the mouse model of synucleinopathy has elevated DCA and LCA. Raised levels of DCA and LCA can lead to liver injury, and an analysis of blood markers of liver dysfunction shows evidence of biliary abnormalities in PD patients, including elevated alkaline phosphatase and bilirubin. Increased bilirubin levels are also evident before PD diagnosis, in individuals at-risk of developing PD. In sum, microbially-derived toxic bile acids are heightened in PD and biliary changes may even precede the onset of overt motor symptoms.