Genetic association and differential expression of PITX2 with acute appendicitis

A Promotion Role of MIR31 in the Process of Vocal Fold Wound Healing

The role of MIR31 in the wound healing process, specifically in vocal fold wound healing (VFWH), remains uncertain despite its potential to facilitate the process. In this study, we first constructed a literature-based pathway to examine both the positive and negative effects of MIR31 on wound healing. We then conducted animal experiments on 20 rats to investigate MIR31 expression at different time points (1, 4, and 8 weeks) after vocal fold injury. Co-expression analysis and pathway analysis were performed to explore the potential function of MIR31 in VFWH. The literature-based pathway suggested that MIR31 could both impede and promote the wound healing process by regulating 14 and 47 wound healing upstream regulators, respectively. However, the rat experiment indicated that MIR31 expression significantly increased after vocal fold injury (p < 5.65 × 10-5) but decreased in the late stage of VFWH compared with the early and middle stages (p < 5.40 × 10-3. Strong co-expression was observed between MIR31 and 17 VFWH-significant genes (Pearson correlation coefficient ∈ (0.63, 0.83)), primarily involved in collagen production. Overall, our findings suggest that MIR31 plays a critical role in VFWH, particularly in collagen synthesis and other biological processes, which warrant further investigation.

Investigation of VGLL3 and sub-target genes in the aetiology of paediatric acute appendicitis: a prospective case-control study

PURPOSE

Vestigial like family member 3 (VGLL3) and its sub-target genes show considerable transcriptomic overlap in terms of several autoimmune and inflammatory diseases. Herein, we investigated the role of VGLL3 rs13074432 polymorphism and its sub-target genes in the aetiology of acute appendicitis (AA).

METHODS

In this prospective case-control study, we included 250 patients (age, 0-18 years) who underwent appendectomy with the diagnosis of AA (patient group; blood and appendix tissue samples) and 200 healthy children (control group; only blood samples) without appendectomy. ELISA method was used for protein-level detection of VGLL3 and sub-target genes expression change in obtained tissue samples, and real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used for mRNA level detection. Genotyping analyses were performed on DNA samples isolated from blood using TaqMan SNP genotyping test.

RESULTS

The frequency of TT variant genotype (p < 0.001) and T allele (p = 0.002) showed a significant decrease in the patient group compared with the control group. No significant correlation was observed between the expression of VGLL3 in the appendiceal tissue and patient clinical and demographic data (p > 0.050).

CONCLUSION

This study revealed that the VGLL3 gene and its sub-target genes are associated with AA aetiology.

Elemental, fatty acid, and protein composition of appendicoliths

Appendicoliths are commonly found obstructing the lumen of the appendix at the time of appendectomy. To identify factors that might contribute to their formation we investigated the composition of appendicoliths using laser ablation inductively coupled plasma mass spectroscopy, gas chromatography, polarized light microscopy, X-ray crystallography and protein mass spectroscopy. Forty-eight elements, 32 fatty acids and 109 human proteins were identified within the appendicoliths. The most common elements found in appendicoliths are calcium and phosphorus, 11.0 ± 6.0 and 8.2 ± 4.2% weight, respectively. Palmitic acid (29.7%) and stearate (21.3%) are the most common fatty acids. Some stearate is found in crystalline form-identifiable by polarized light microscopy and confirmable by X-ray crystallography. Appendicoliths have an increased ratio of omega-6 to omega-3 fatty acids (ratio 22:1). Analysis of 16 proteins common to the appendicoliths analyzed showed antioxidant activity and neutrophil functions (e.g. activation and degranulation) to be the most highly enriched pathways. Considered together, these preliminary findings suggest oxidative stress may have a role in appendicolith formation. Further research is needed to determine how dietary factors such as omega-6 fatty acids and food additives, redox-active metals and the intestinal microbiome interact with genetic factors to predispose to appendicolith formation.

Impact of Human Genetic Variation on C-Reactive Protein Concentrations and Acute Appendicitis

Background

Acute appendicitis is one of the most common abdominal emergencies worldwide. Both environmental and genetic factors contribute to the disease. C-reactive protein (CRP) is an important biomarker in the diagnosis of acute appendicitis. CRP concentrations are significantly affected by genetic variation. However, whether such genetic variation is causally related to appendicitis risk remains unclear. In this study, the causal relationship between single-nucleotide polymorphisms (SNPs) associated with circulating CRP concentrations and the risk and severity of acute appendicitis was investigated.

Methods

CRP concentrations in serum of appendicitis patients (n = 325) were measured. Appendicitis was categorized as complicated/uncomplicated and gangrenous/non-gangrenous. Imputed SNP data (n = 287) were generated. A genome-wide association study (GWAS) on CRP concentrations and appendicitis severity was performed. Intersection and colocalization of the GWAS results were performed with appendicitis and CRP-associated loci from the Pan-UKBB cohort. A functional-genomics approach to prioritize genes was employed.

Results

Thirteen percent of significant CRP quantitative trait loci (QTLs) that were previously identified in a large cohort of healthy individuals were replicated in our small patient cohort. Significant enrichment of CRP-QTLs in association with appendicitis was observed. Among these shared loci, the two top loci at chromosomes 1q41 and 8p23.1 were characterized. The top SNP at chromosome 1q41 is located within the promoter of H2.0 Like Homeobox (HLX) gene, which is involved in blood cell differentiation, and liver and gut organogeneses. The expression of HLX is increased in the appendix of appendicitis patients compared to controls. The locus at 8p23.1 contains multiple genes, including cathepsin B (CTSB), which is overexpressed in appendix tissue from appendicitis patients. The risk allele of the top SNP in this locus also increases CTSB expression in the sigmoid colon of healthy individuals. CTSB is involved in collagen degradation, MHC class II antigen presentation, and neutrophil degranulation.

Conclusions

The results of this study prioritize HLX and CTSB as potential causal genes for appendicitis and suggest a shared genetic mechanism between appendicitis and CRP concentrations.

Distribution of RET proto-oncogene variants in children with appendicitis

Background

In addition to patient‐related systemic factors directing the immune response, the pathomechanisms of appendicitis (AP) might also include insufficient drainage leading to inflammation caused by decreased peristalsis. Genetic predisposition accounts for 30%–50% of AP. M. Hirschsprung (HSCR), also characterized by disturbed peristalsis, is associated with variants in the RET proto‐oncogene. We thus hypothesized that RET variants contribute to the etiology of AP.

Methods

DNA from paraffin‐embedded appendices and clinical data of 264 children were analyzed for the RET c.135A>G variant (rs1800858, NC_000010.11:g.43100520A>G). In 46 patients with gangrenous or perforated AP (GAP), peripheral blood DNA was used for RET sequencing.

Results

Germline mutations were found in 13% of GAP, whereas no RET mutations were found in controls besides the benign variant p.Tyr791Phe (NC_000010.11:g.43118460A>T). In GAP, the polymorphic G‐allele in rs2435352 (NC_000010.11:g.43105241A>G) in intron 4 was underrepresented (p = 0.0317).

Conclusion

Our results suggest an impact of the RET proto‐oncogene in the etiology of AP. Mutations were similar to patients with HSCR but no clinical features of HSCR were observed. The pathological phenotypes in both populations might thus represent a multigenic etiology including RET germline mutations with phenotypic heterogeneity and incomplete penetrance.

Association Between NEDD4L Variation and the Genetic Risk of Acute Appendicitis: A Multi-institutional Genome-Wide Association Study

Importance

The familial aspect of acute appendicitis (AA) has been proposed, but its hereditary basis remains undetermined.

Objective

To identify genomic variants associated with AA.

Design, Setting, and Participants

This genome-wide association study, conducted from June 21, 2019, to February 4, 2020, used a multi-institutional biobank to retrospectively identify patients with AA across 8 single-nucleotide variation (SNV) genotyping batches. The study also examined differential gene expression in appendiceal tissue samples between patients with AA and controls using the GSE9579 data set in the National Institutes of Health's Gene Expression Omnibus repository. Statistical analysis was conducted from October 1, 2019, to February 4, 2020.

Main Outcomes and Measures

Single-nucleotide variations with a minor allele frequency of 5% or higher were tested for association with AA using a linear mixed model. The significance threshold was set at P = 5 × 10-8.

Results

A total of 29 706 patients (15 088 women [50.8%]; mean [SD] age at enrollment, 60.1 [17.0] years) were included, 1743 of whom had a history of AA. The genomic inflation factor for the cohort was 1.003. A previously unknown SNV at chromosome 18q was found to be associated with AA (rs9953918: odds ratio, 0.99; 95% CI, 0.98-1.00; P = 4.48 × 10-8). This SNV is located in an intron of the NEDD4L gene. The heritability of appendicitis was estimated at 30.1%. Gene expression data from appendiceal tissue donors identified NEDD4L to be among the most differentially expressed genes (14 of 22 216 genes; β [SE] = -2.71 [0.44]; log fold change = -1.69; adjusted P = .04).

Conclusions and Relevance

This study identified SNVs within the NEDD4L gene as being associated with AA. Nedd4l is involved in the ubiquitination of intestinal ion channels and decreased Nedd4l activity may be implicated in the pathogenesis of AA. These findings can improve the understanding of the genetic predisposition to and pathogenesis of AA.

Novel molecular biomarkers and diagnosis of acute appendicitis in children

Reliable and efficient diagnosis of pediatric appendicitis is essential for the establishment of a clinical management plan and improvement of patient outcomes. Current strategies used to diagnose a child presenting with a suspected appendicitis include laboratory studies, clinical scores and diagnostic imaging. Although these modalities work in conjunction with each other, one optimal diagnostic strategy has yet to be agreed upon. The recent introduction of precision medicine techniques such as genomics, transcriptomics, proteomics and metabolomics has increased both the diagnostic sensitivity and specificity of appendicitis. Using these novel strategies, the integration of precision medicine into clinical practice via point-of-care technologies is a plausible future. These technologies would assist in the screening, diagnosis and prognosis of pediatric appendicitis.

Trends in Appendicitis Among Pregnant Women, the Risk for Cardiac Arrest, and Maternal-Fetal Mortality

Background

Appendicitis is the most common extra-uterine surgical emergency requiring immediate intervention during pregnancy. However, risks for mortality and morbidity among pregnant women with appendicitis remain poorly understood. This study was conducted to determine the temporal trends of appendicitis in pregnant women, and to calculate the risk of maternal–fetal mortality and near-miss marker (i.e., cardiac arrest) among pregnant women in general, and by race/ethnicity.

Methods

We conducted this retrospective study using data from the Nationwide Inpatient Sample (NIS) from January 1, 2002, through December 31, 2015. Joinpoint regression was used to estimate and describe temporal changes in the rates of all and acute appendicitis during the 14-year study period. We also estimated the risk of cardiac arrest, maternal, and fetal mortality among mothers of various racial/ethnic groups with a diagnosis of acute appendicitis. Within each group, patients without acute appendicitis were the referent category.

Results and conclusions

Out of the 58 million pregnancy hospitalizations during the study period, 63,145 cases (10.74 per 10,000 hospitalizations) were for acute appendicitis. There was a 5% decline (95% CI: − 5.1, − 5.0) in the rate of appendicitis hospitalizations over the period of the study. After adjusting for covariates, pregnant mothers with acute appendicitis had increased likelihood when compared to those without acute appendicitis to suffer fetal loss (OR: 2.05, 95% CI: 1.85–2.28) and nearly fivefold increase for inpatient maternal death. In conclusion, appendicitis during pregnancy remains an important cause of in-hospital maternal–fetal mortality overall and regardless of race/ethnicity.

Simultaneous acute appendicitis in identical twin boys

Acute appendicitis is one of the most common causes of abdominal pain in children but remains a diagnostic challenge, and insight into the aetiology of the condition is lacking. A case of simultaneous acute appendicitis in monozygotic twin boys is reported here. Familial aggregation in acute appendicitis has been described, but the underlying causes for this are not well understood. The patients reported here were both genetically identical and lived a mostly identical lifestyle. Their simultaneous presentation would be exceedingly rare if explained entirely by chance, suggesting a role for both genetic and environmental influences. Increased knowledge of this occurrence may assist in prompt diagnosis and reporting on the incidence and timing of appendicitis in monozygotic twins could better elucidate the genetic and environmental factors that predispose to this disease.