Novel molecular biomarkers and diagnosis of acute appendicitis in children

Gene Expression Profiling in Pediatric Appendicitis

Importance

Appendicitis is the most common indication for urgent surgery in the pediatric population, presenting across a range of severity and with variable complications. Differentiating simple appendicitis (SA) and perforated appendicitis (PA) on presentation may help direct further diagnostic workup and appropriate therapy selection, including antibiotic choice and timing of surgery.

Objective

To provide a mechanistic understanding of the differences in disease severity of appendicitis with the objective of developing improved diagnostics and treatments, specifically for the pediatric population.

Design, Setting, and Participants

The Gene Expression Profiling of Pediatric Appendicitis (GEPPA) study was a single-center prospective exploratory diagnostic study with transcriptomic profiling of peripheral blood collected from a cohort of children aged 5 to 17 years with abdominal pain and suspected appendicitis between November 2016 and April 2017 at the Alberta Children's Hospital in Calgary, Alberta, Canada, with data analysis reported in August 2023. There was no patient follow-up in this study.

Exposure

SA, PA, or nonappendicitis abdominal pain.

Main Outcomes and Measures

Blood transcriptomics was used to develop a hypothesis of underlying mechanistic differences between SA and PA to build mechanistic hypotheses and blood-based diagnostics.

Results

Seventy-one children (mean [SD] age, 11.8 [3.0] years; 48 [67.6%] male) presenting to the emergency department with abdominal pain and suspected appendicitis were investigated using whole-blood transcriptomics. A central role for immune system pathways was revealed in PA, including a dampening of major innate interferon responses. Gene expression changes in patients with PA were consistent with downregulation of immune response and inflammation pathways and shared similarities with gene expression signatures derived from patients with sepsis, including the most severe sepsis endotypes. Despite the challenges in identifying early biomarkers of severe appendicitis, a 4-gene signature that was predictive of PA compared to SA, with an accuracy of 85.7% (95% CI, 72.8-94.1) was identified.

Conclusions

This study found that PA was complicated by a dysregulated immune response. This finding should inform improved diagnostics of severity, early management strategies, and prevention of further postsurgical complications.

[Factors associated with normal leukocyte count and C-reactive protein in adults with acute appendicitis: a retrospective cohort study]

OBJECTIVE

To identify the factors associated with normal leukocyte count and C-reactive protein (CRP) in adults with acute appendicitis.

MATERIAL AND METHODS

A retrospective cohort study included patients aged 18-60 years after surgeries for acute appendicitis. Convenience sampling was used to select medical records, and variables such as age, sex, weight, height, origin, self-medication, diabetes (DM2), high blood pressure (HBP), type of appendicitis, duration of illness, preoperative time, type of appendectomy, operative time, and hospital stay were analyzed. Patients were categorized into those with normal and abnormal inflammatory parameters. The SPSS version 28 software was used for analysis.

RESULTS

We included 333 patients; 11.11% ones had normal inflammatory parameters. Both groups had mean age of approximately 33 years. Men comprised 56.76% and 57.43%in both groups, respectively. The abnormal group had shorter mean preoperative time, and catarrhal appendicitis was more common in the normal group. Multivariate analysis revealed that rural origin and self-medication were significantly associated with normal inflammatory parameters.

CONCLUSION

The prevalence of normal inflammatory parameters in acute appendicitis patients was 11.11%. Rural origin, self-medication, shorter preoperative time, and catarrhal appendicitis were significantly associated with normal inflammatory parameters in this context.

Post-Traumatic Stress Response and Appendicitis in Children-Clinical Usefulness of Selected Biomarkers

Acute appendicitis is an inflammatory process which is one of the most frequent global causes of surgical interventions in children. The goal of the study was to determine whether acute phase proteins, that is, C-reactive protein (CRP), procalcitonin (PCT) and neutrophil gelatinase-associated lipocalin (NGAL), interleukin 6 (IL-6), transforming growth factor-beta1 (TGF-β1) and cortisol (HC) play a role in the pathomechanism of post-trauma stress response of the organism and to establish the impact of the applied surgical procedure and/or of inflammation on their concentrations. An additional purpose was to establish the clinical usefulness of the studied biomarkers in the diagnostics of appendicitis. CRP concentrations were quantified via the immunoturbidimetric method, while the levels of IL-6 and PCT were assessed using a bead-based multiplexed immunoassay system in a microplate format (Luminex xMAP technology); NGAL, TGF-β1 and cortisol concentrations were determined via the enzyme-linked immunosorbent assay (ELISA) technique. All the investigated biomarkers were assayed twice, i.e., immediately before the surgery and 12-24 h after its completion. Significant increases in CRP, IL-6 and PCT concentrations were found in all children subjected to laparoscopic surgeries (p = 0.001, p = 0.006, and p = 0.009, respectively) and open (classic) surgeries (p = 0.001, p = 0.016, and p = 0.044, respectively) compared to the initial concentrations. The patients undergoing classical surgery moreover presented with significant (p = 0.002, and p = 0.022, respectively) increases in NGAL and TGF-β1 levels after the procedures. In a group of children undergoing laparoscopic surgery, the appendicitis induced an increase in cortisol concentration, whereas in patients undergoing classical surgery the increase in the levels of this biomarker was caused by the type of performed surgical procedure. Simultaneously assaying the levels of CRP, NGAL and IL-6 (p = 0.008, p = 0.022, and p = 0.000, respectively) may prove useful in clinical practice, enabling the diagnosis of appendicitis in paediatric patients reporting to a hospital with abdominal pains, in addition to data from anamnesis and from clinical or ultrasound examination. The performed study confirms the participation of examined biomarkers in the pathomechanism of post-injury stress reaction of the organism to surgical trauma.

The role of IL-6, thiol-disulfide homeostasis, and inflammatory biomarkers in the prediction of acute appendicitis in children: a controlled study

PURPOSE

This study aimed to examine the diagnostic value of IL-6, thiol-disulfide homeostasis, complete blood count and inflammatory biomarkers in the prediction of acute appendicitis in children.

METHODS

The study was designed as a prospective and controlled study in children-the study was conducted at a tertiary referential university hospital between May 2020 and April 2021. Patients were divided between study groups and one control group (CG): 1: confirmed acute appendicitis group (AAP); 2: perforated appendicitis group (PAP); and 3: non-specified abdominal pain (NAP). The age and gender of the patients were determined. The following listed laboratory parameters were compared between groups: TOS: total oxidative status, TAS: total antioxidant status, OSI: oxidative stress index, TT: total thiol, NT (µmol/L): native thiol, DIS: disulfide, IL-6: interleukin 6, TNF-a: tumor necrosis factor-alpha, WBC: white blood cell, NEU: neutrophil, NEU%: neutrophil percentage, LY: lymphocyte, LY%: lymphocyte percentage, PLT: platelet, MPV: mean platelet volume NLR: neutrophil lymphocyte ratio, CRP: C-reactive protein, LCR: lymphocyte CRP ratio, and serum lactate.

RESULTS

The TOS level of the PAP group was found to be significantly higher than that in the AAP, NAP and control groups (p = 0.006, < 0.001 and p < 0.001). TAS, TT, and NT levels in the PAP group were significantly lower than those in the AAP, NAP and control groups. OSI was significantly higher in the PAP group than in the other groups. The TT and NT levels of the NAP group were both similar to those of the control group. Serum DIS level was similar between the AAP and PAP groups, AAP and NAP groups, and NAP and control groups. Serum IL-6 and TNF-α levels were found to be significantly higher in the PAP group compared to those in all groups. The WBC, NEU, and NEU% values were found to be significantly higher in the PAP group than those in the NAP and control groups, while LY and LY% values were found to be significantly lower. PAP and AAP groups were found to be similar in terms of WBC, NEU, LYM, NEU%, and LYM% values. PLT and MPV values and serum lactate values did not show a significant difference between the groups. NLR was similar in the AAP and PAP groups. A significant increase in CRP versus a decrease in LCR was detected in the PAP group compared to that in the AAP group. Multivariate analysis demonstrated that only IL-6 has significant estimated accuracy rates as 80% for the control group, 78.8% for AAP, 96.9% for PAP, and 81.6% for NAP.

CONCLUSION

Rather than AAP, PAP caused significantly higher oxidative stress (increased TOS and OSI), and lower antioxidation capacity (decreased TT and NT). IL-6 levels can provide a significant stratification. Nevertheless, simply detecting WBC or CRP is not enough to distinguish the specific pathology in acute appendicitis and related conditions.

The Diagnostic Differentiation Challenge in Acute Appendicitis: How to Distinguish between Uncomplicated and Complicated Appendicitis in Adults

(1) Background: How to best define, diagnose and differentiate uncomplicated from complicated acute appendicitis remains debated. Hence, the aim of this review was to present an overview of the current knowledge and emerging field of acute appendicitis with a focus on the diagnostic differentiation of severity currently subject to ongoing investigations. (2) Methods: We conducted a PubMed search using the MeSH terms “appendicitis AND severity” and “appendicitis AND classification”, with a focus on studies calling appendicitis as ‘uncomplicated’ or ‘complicated’. An emphasis on the last 5 years was stressed, with further studies selected for their contribution to the theme. Further studies were retrieved from identified full-text articles and included per the authors’ discretion. (3) Results: The assumption that appendicitis invariably will proceed to perforation has been outdated. Both uncomplicated and complicated appendicitis exist with likely different pathophysiology. Hence, this makes it important to differentiate disease severity. Clinicians must diagnose appendicitis, but, in the next step, also differentiate between uncomplicated and complicated appendicitis in order to allow for management decisions. Diagnostic accuracy without supportive imaging is around 75–80% and, based on clinical judgement and blood tests alone, the negative appendectomy rate has been described as high as 36%. More research is needed on available biomarkers, and the routine use of imaging still remains debated. Scoring systems have the potential to improve diagnostic accuracy, but no scoring system has yet been validated for differentiating disease severity. Currently, no universally agreed definition exists on what constitutes a complicated appendicitis. (4) Conclusions: Uncomplicated and complicated appendicitis appear to have different pathophysiology and should be treated differently. The differentiation between uncomplicated and complicated appendicitis remains a diagnostic challenge.

The potential role of interleukin-6, endotoxin and C-reactive protein as standard biomarkers for acute appendicitis in adults

Introduction/Objective. Acute appendicitis (AA) is by far the most frequent urgent condition in abdominal surgery and numerous biomarkers may help the physician to diagnose and even predict the severity of the disease. The objective of the paper was to determine the accuracy of C-reactive protein (CRP), interleukin-6 (IL-6) and endotoxin and compare it with the diagnostic value of Alvarado score (AS) in adults surgically treated for AA. Methods. Sixty-seven patients were diagnosed with AA using AS. Prior to surgery serum levels of inflammatory biomarkers were determined and together with AS were respectively compared to the results of histopathological analysis of specimens. The patients were divided into three group according to the histopathological assessment. Results. The univariate analysis revealed that the increase of CRP level by one unit increases the probability of complicated AA (CoAA) occurence by 1% (1.00 to 1.02, p < 0.05). ROC curve analysis has revealed that CRP has better capacity to predict supurative AA (SAAs)/CoAAs than catarrhal AA (CAA), with the cut-of value 19.45. Increase of AS value by one unit produced 2.98 fold increase of the probability of CoAA occurrence (1.60 to 5.57, p < 0.001), while positive AS value increases the probability of CoAA occurrence 24.67 times (4.94 to 123.12; p < 0.001). ROC curve analysis was demonstrated that AS may better predict CoAAs than CAAs/SAAs, with the cut-off value 8.50. Conclusion. AS and CRP should be routinely used combined as powerful tools for diagnosis and prediction of complicated AA.