Salivary biomarker for acute appendicitis in children: a pilot study

Diagnostic Performance of Serum Leucine-Rich Alpha-2-Glycoprotein 1 in Pediatric Acute Appendicitis: A Prospective Validation Study

Introduction: Leucine-rich alpha-2-glycoprotein 1(LRG-1) is a human protein that has shown potential usefulness as a biomarker for diagnosing pediatric acute appendicitis (PAA). This study aims to validate the diagnostic performance of serum LRG-1 in PAA. Material and Methods: This work is a subgroup analysis from BIDIAP (BIomarkers for DIagnosing Appendicitis in Pediatrics), a prospective single-center observational cohort, to validate serum LRG-1 as a diagnostic tool in PAA. This analysis included 200 patients, divided into three groups: (1) healthy patients undergoing major outpatient surgery (n = 56), (2) patients with non-surgical abdominal pain (n = 52), and (3) patients with a confirmed diagnosis of PAA (n = 92). Patients in group 3 were divided into complicated and uncomplicated PAA. In all patients, a serum sample was obtained during recruitment, and LRG-1 concentration was determined by Enzyme-Linked ImmunoSorbent Assay (ELISA). Comparative statistical analyses were performed using the Mann-Whitney U, Kruskal-Wallis, and Fisher's exact tests. The area under the receiver operating characteristic curves (AUC) was calculated for all pertinent analyses. Results: Serum LRG-1 values, expressed as median (interquartile range) were 23,145 (18,246-27,453) ng/mL in group 1, 27,655 (21,151-38,795) ng/mL in group 2 and 40,409 (32,631-53,655) ng/mL in group 3 (p < 0.0001). Concerning the type of appendicitis, the serum LRG-1 values obtained were 38,686 (31,804-48,816) ng/mL in the uncomplicated PAA group and 51,857 (34,013-64,202) ng/mL in the complicated PAA group (p = 0.02). The area under the curve (AUC) obtained (group 2 vs. 3) was 0.75 (95% CI 0.67-0.84). For the discrimination between complicated and uncomplicated PAA, the AUC obtained was 0.66 (95% CI 0.52-0.79). Conclusions: This work establishes normative health ranges for serum LRG-1 values in the pediatric population and shows that serum LRG-1 could be a potentially helpful tool for diagnosing PAA in the future. Future prospective multicenter studies, with the parallel evaluation of urinary and salivary LRG-1, are necessary to assess the implementability of this molecule in actual clinical practice.

Utility of Ischemia-Modified Albumin as a Biomarker for Acute Appendicitis: A Systematic Review and Meta-Analysis

BACKGROUND

Acute appendicitis is a frequently encountered surgical emergency. Despite several scoring systems, the possibility of delayed diagnosis persists. In addition, a delayed diagnosis leads to an increased risk of complicated appendicitis. Hence, there is a need to identify biological markers to help clinicians rapidly and accurately diagnose and prognosticate acute appendicitis with a high sensitivity and specificity. Although several markers have been evaluated, the pressing concern is still the low specificity of these markers. One such marker is serum ischemia-modified albumin (IMA), which can be a novel biomarker for accurately diagnosing and prognosticating acute appendicitis.

METHODS

The authors conducted a systematic search of the PubMed, EMBASE, Web of Science, and Scopus databases through February 2023 as per the PRISMA guidelines. The difference in the levels of IMA between patients with acute appendicitis vs. healthy controls, and the difference in the levels of IMA between patients with complicated vs. non-complicated acute appendicitis were taken as the outcome measures. Statistical analysis was performed using a random effects model and mean difference (MD) was calculated. The methodological quality of the studies was assessed by utilizing the Newcastle-Ottawa scale.

RESULTS

A total of six prospective comparative studies were included in the meta-analysis. The analysis revealed that the mean level of serum IMA was significantly raised in the acute appendicitis group (MD 0.21, 95% CI 0.05 to 0.37, p = 0.01). Similarly, the mean serum IMA levels were also raised in the complicated appendicitis group compared to the non-complicated appendicitis group (MD 0.05, 95% CI 0.01 to 0.10, p = 0.02). Three of the studies included were, however, of poor methodological quality.

CONCLUSIONS

Serum IMA is a viable potential marker for diagnosing and prognosticating acute appendicitis. However, due to the limited methodological quality of available studies, further prospectively designed and adequately powered studies are needed.

Leucine-Rich Alpha-2-Glycoprotein as a non-invasive biomarker for pediatric acute appendicitis: a systematic review and meta-analysis

The aim of this study was to analyze the diagnostic performance of Leucine-Rich Alpha-2-Glycoprotein (LRG1) in pediatric acute appendicitis (PAA). We conducted a systematic review of the literature in the main databases of medical bibliography. Two independent reviewers selected the articles and extracted relevant data. Methodological quality was assessed using the QUADAS2 index. A synthesis of the results, standardization of the metrics and 4 random-effect meta-analyses were performed. Eight studies with data from 712 participants (305 patients with confirmed diagnosis of PAA and 407 controls) were included in this review. The random-effect meta-analysis of serum LRG1 (PAA vs control) resulted in a significant mean difference (95% CI) of 46.76 μg/mL (29.26-64.26). The random-effect meta-analysis for unadjusted urinary LRG1 (PAA vs control) resulted in a significant mean difference (95% CI) of 0.61 μg/mL (0.30-0.93). The random-effect meta-analysis (PAA vs control) for urinary LRG1 adjusted for urinary creatinine resulted in a significant mean difference (95% CI) of 0.89 g/mol (0.11-1.66).   Conlusion: Urinary LRG1 emerges as a potential non-invasive biomarker for the diagnosis of PAA. On the other hand, due to the high between-study heterogeneity, the results on serum LRG1 should be interpreted with caution. The only study that analyzed salivary LRG1 showed promising results. Further prospective studies are needed to confirm these findings. What is Known: • Pediatric acute appendicitis continues to be a pathology with a high rate of diagnostic error. • Invasive tests, although useful, are a source of stress for patients and their parents. What is New: • LRG1 emerges as a promising urinary and salivary biomarker for the noninvasive diagnosis of pediatric acute appendicitis.

The BIDIAP index: a clinical, analytical and ultrasonographic score for the diagnosis of acute appendicitis in children

BACKGROUND

Pediatric acute appendicitis (PAA) continues to be a diagnostic challenge today. The diagnostic performance of classical indices is only moderate, especially in pediatric population. This study aimed to define a clinical, radiological and analytical index for the diagnosis of PAA.

MATERIALS AND METHODS

This prospective study included 151 patients divided into two groups: (1) 53 patients with non-surgical abdominal pain (NSAP) and (2) 98 patients with a confirmed PAA. Sociodemographic and clinical characteristics were compared between groups using the Mann-Whitney U test and the Fisher exact test. To identify the predictors of PAA, we performed a multivariable logistic regression using a forward stepwise analysis and we assigned multiples of integer values to the selected variables. The diagnostic performance of the index was assessed by calculating the area under the receiver operating characteristic curve. Intra-cohort calibration was assessed with the Hosmer-Lemeshow test.

RESULTS

We developed the BIDIAP index (BIomarkers for the DIagnosis of Appendicitis in Pediatrics), which included three variables that independently predicted higher odds of PAA: appendiceal caliber (≥ 6.9 mm), systemic immune-inflammation index (≥ 890) and peritoneal irritation, which scored 4, 3 and 2 points, respectively. Mean (SD) score of the participants was 2.38 (2.06) in group 1 and 7.89 (1.50) in group 2. The area under the ROC was 0.97 (95% CI 0.95-0.99). The cut-off point was established at 4 points, resulting in a sensitivity of 98.98% and a specificity of 77.78%.

CONCLUSIONS

The BIDIAP index has an exceptional diagnostic performance in PAA. The importance of these results lies in its novelty and in the simplicity of the index. Although external validation will be necessary, initial results look promising.

Diagnostic Accuracy of Leucine-Rich α-2-Glycoprotein 1 as a Non-Invasive Salivary Biomarker in Pediatric Appendicitis

The aim of this study is to evaluate the diagnostic accuracy of leucine-rich α-2-glycoprotein 1 (LRG1) in saliva as a novel biomarker for acute appendicitis in the pediatric population. From October 2021 to June 2022, 92 children aged 5 to 17 years who presented with acute abdomen and suspected acute appendicitis were enrolled in this prospective study. The parameters documented included demographic and clinical information, as well as operative and postoperative data. Patients were divided into two groups: those with acute appendicitis who underwent laparoscopic appendectomy (n = 46) and those without appendicitis (n = 46). The total white blood cell (WBC) count, percent of neutrophils, C-reactive protein (CRP) level, and salivary LRG1 were compared between groups. A commercially available enzyme-linked immunosorbent assay (ELISA) LRG kit was used to measure the LRG levels. The median salivary LRG1 level was significantly higher in the group of children with pathohistologically confirmed acute appendicitis compared to the control group: 233.45 ng/mL (IQR 114.9, 531.2) vs. 55.95 ng/mL (IQR 51.5, 117.9), p < 0.001. LRG1 had an overall good receiver-operator characteristic area under the curve of 0.85 (95% CI 0.76-0.92; p < 0.001). The optimal LRG1 cutoff with best separation between acute appendicitis and the controls was >352.6 ng/mL (95% CI from >270.7 to >352.6). Although the specificity was 100% at this cutoff, the sensitivity for identifying appendicitis was 36%. In addition, a significant difference was found between groups in the laboratory values of all inflammatory markers tested: WBC, absolute neutrophil count, and CRP (p < 0.001 for all). Although LRG1 in saliva showed a good AUC parameter and significantly higher values in patients with acute appendicitis compared to the controls, its usefulness in the patient population who present at emergency departments with abdominal pain is debatable. Future studies should focus on investigating its diagnostic potential.

Diagnostic Utility of Serum Leucine-Rich α-2-Glycoprotein 1 for Acute Appendicitis in Children

PURPOSE

The aim of this study is to assess the diagnostic utility of serum leucine-rich α-2-glycoprotein 1 (LRG1) in pediatric patients with acute abdominal pain, admitted to the emergency surgical unit, in order to make a prompt and accurate diagnosis of acute appendicitis.

PATIENTS AND METHODS

Pediatric patients older than 5 years of age who presented to the emergency department from 15 October 2021 to 30 June 2022 with acute abdominal pain and suspected acute appendicitis were prospectively recruited in the study. Demographic and clinical data, as well as operative and postoperative data, were recorded. A total of 92 patients were equally distributed into two groups: children with acute appendicitis who underwent laparoscopic appendectomy and non-appendicitis patients, presenting with non-specific abdominal pain. LRG1 levels were determined using a commercially available LRG1 enzyme-linked immunosorbent assay (ELISA) kit. Serum LRG1 levels, as well as other inflammatory markers (white blood cell count (WBC), C-reactive protein (CRP) and absolute neutrophil count) were compared between groups.

RESULTS

The median level of LRG1 in serum was significantly higher in the group of children with pathohistologically confirmed acute appendicitis than in the control group, at 350.3 µg/mL (interquartile range (IQR) 165.2-560.3) and 25.7 µg/mL (IQR 14.7-36.8) (p < 0.001), respectively. Receiver operating characteristic area under the curve for LRG1 from serum was 1.0 (95% CI 0.96-1.00; p < 0.001) and the value of >69.1 µg/mL was found to perfectly separate acute appendicitis cases from controls. Additionally, as expected, each of the examined laboratory inflammatory markers provided a significantly higher values in the acute appendicitis group compared to the control group: WBC 14.6 × 109/L (IQR 12.7, 18.7) vs. 7.0 × 109/L (IQR 5.4, 9.0) (p < 0.001), CRP 16.3 mg/dL (IQR 6.9, 50.4) vs. 2.2 mg/dL (IQR 2, 2) (p < 0.001) and absolute neutrophil count 84.6% (IQR 79.5, 89.0) vs. 59.5% (IQR 51.5, 68.6) (p < 0.001).

CONCLUSIONS

LRG1 in the serum was found to be a promising novel biomarker, with excellent differentiation of acute appendicitis from non-appendicitis cases in children presenting with non-specific abdominal pain.

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.

Diagnostic performance of serum pentraxin-3 in pediatric acute appendicitis: a prospective diagnostic validation study

INTRODUCTION

Pediatric acute appendicitis (PAA) is a pathology with a high rate of diagnostic error. The search for new diagnostic tools is justified by the high morbidity and healthcare costs associated with diagnostic error.

METHODS

We designed a prospective study to validate serum pentraxin-3 (PTX3) as a diagnostic tool in PAA. Participants were divided into three groups: (1) patients with no underlying pathology (2) patients with non-surgical abdominal pain and (3) patients with a confirmed diagnosis of PAA. For further analyses, patients in group 3 were divided into complicated or uncomplicated PAA. Quantitative variables were expressed as medians and interquartile ranges and categorical variables as percentages. Quantitative variables were compared using the Kruskal-Wallis test and the Mann-Whitney U test. Diagnostic performance was evaluated with ROC curves.

RESULTS

This study included 215 patients divided into group 1 (n = 63), group 2 (n = 53) and group 3 (n = 99). Median serum PTX3 values were 2.54 (1.70-2.95) ng/mL, 3.29 (2.19-7.64) ng/mL and 8.94 (6.16-14.05) in groups 1, 2 and 3, respectively (p = 0.001). Patients with complicated PAA showed significantly higher values than patients with uncomplicated PAA (p = 0.04). The AUC (group 2 vs. 3) was 0.77 (95% CI 0.69-0.85) and the best cut-off point was at 7.28 ng/mL, with a sensitivity of 61.3% and a specificity of 73.1%. The AUC (complicated vs. uncomplicated PAA) was 0.65 (95% CI 0.54-0.77) and the best cut-off point was 12.33 ng/mL, with a sensitivity of 51.72% and a specificity of 72.73%.

CONCLUSIONS

The diagnostic ability of serum PTX3 in PAA is only moderate and therefore it cannot be considered a definitive diagnostic test. The discriminatory ability of PTX3 between complicated and uncomplicated PAA is poor. These findings, which contrast with those reported to date, should be validated with future properly designed prospective studies.

Diagnostic performance of calprotectin and APPY-1 test in pediatric acute appendicitis: a systematic review and a meta-analysis

BACKGROUND

Pediatric acute appendicitis (AA) is a challenging pathology to diagnose. In the last decades, multiple biomarkers have been evaluated in different human biological samples to improve diagnostic performance. This study aimed to examine the diagnostic performance of serum, fecal and urinary calprotectin as well as the role of the APPY-1 biomarker panel in pediatric acute appendicitis.

METHODS

We conducted a systematic review of the literature that involved an extensive search in the main databases of medical bibliography (Medline, PubMed, Web of Science and SciELO). Two independent reviewers selected the relevant articles based on the previously defined inclusion and exclusion criteria. Methodological quality of the selected article was rated using the QUADAS2 index. Data extraction was performed by two independent reviewers. A synthesis of the results, a standardization of the metrics and two random-effect meta-analyses, one for serum calprotectin and one for APPY-1, were performed.

RESULTS

The research resulted in 173 articles. Thirty-eight duplicates were removed. Among the remaining 135 articles, we excluded 125 following the inclusion and exclusion criteria, resulting in the 10 studies included in this review. This systematic review included data from of 3901 participants (1276 patients with confirmed diagnosis of AA and 2625 controls). The age of the participants ranged from 0 to 21 years. Four of the studies compared serum calprotectin values and reported significant differences between groups, but inconsistent results regarding cutoff points, sensitivity and specificity. Two publications compared urinary values of calprotectin and presented inconsistent results regarding sensitivity and specificity as well. One publication evaluated the diagnostic performance of fecal calprotectin, but it did not provide data on measured values. Four studies evaluated the diagnostic performance of APPY-1 test in pediatric acute appendicitis. The calculated pooled sensitivity and specificity of those studies were 97.37 (95% CI 95.60-98.44) and 36.74 (95% CI 32.28-41.44), respectively, and the calculated pooled NLR, 0.0714 (95% CI 0.041-0.115).

CONCLUSION

Serum calprotectin has limited diagnostic yield in pediatric acute appendicitis. Its performance seems to increase with the hours of clinical evolution and in advanced AA, although the evidence is limited. There is not enough evidence on the usefulness of urinary or fecal calprotectin in the diagnosis of pediatric acute appendicitis. On the other hand, the APPY-1 is a reliable test to exclude the diagnosis of AA in patients at low or moderate risk according to PAS and Alvarado Score.

Systematic review and meta-analysis of the effects of the perioperative enhanced recovery after surgery concept on the surgical treatment of acute appendicitis in children

BACKGROUND

Enhanced recovery after surgery (ERAS), as a new concept in surgery, has dramatically changed the mode of perioperative treatment for children with acute appendicitis.

METHODS

The retrieval strategy developed by the Cochrane Collaboration was conducted using the CNKI database, Wanfang Medical Network, PubMed, EBSCO, Medline, and Cochrane database by combining subject headings and free words. A review of the randomized controlled trials on the use of the ERAS concept in the perioperative treatment of acute appendicitis in children was conducted between the establishment of the database and May 15, 2021. Keywords included enhanced recovery after surgery, fast track surgery, ERAS, FTS, child, infant, and appendicitis. The quality of the literature was evaluated according to the RevMan 5.3 software provided by the Cochrane Collaboration.

RESULTS

Five randomized controlled trials on ERAS in children with acute appendicitis were finally included. The heterogeneity of postoperative stay time was tested in 4 studies using continuous variables, with Chi-squared test (Chi²) =221.52, degree of freedom (df) =3, I²=99%>50%. An overall analysis using a random effects model showed that the ERAS group was significantly different compared to the control group [Z=5.26; mean difference (MD) =-1.65; 95% CI: -2.27 to -1.03; P<0.00001]. The heterogeneity of the readmission rate was tested in 5 studies using dichotomous variables, with Chi²=5.11, df =3, I²=41%<50%, P=0.91. Overall analysis using a fixed effects model showed no statistically significant difference between the ERAS group and the control group [Z=0.80; odds ratio (OR) =1.16; 95% CI: 0.81 to 1.66; P=0.42]. The heterogeneity of the recurrence rate was tested in 4 studies using dichotomous variables, with Chi²=3.73, df =3, I²=20%<50%, P=0.29. Overall analysis using a fixed effects model showed no statistically significant difference between the ERAS group and the control group (Z=1.14; OR =0.76; 95% CI: 0.47 to 1.22; P=0.26).

DISCUSSION

The results of the meta-analysis confirmed that perioperative application of the ERAS concept in children with acute appendicitis can promote the rehabilitation of children, reduce the postoperative stay time, and reduce the readmission rate and reoperation rate.

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.

Host-Based Biomarkers in Saliva for the Diagnosis of Pulmonary Tuberculosis in Children: A Mini-Review

The diagnosis of pulmonary tuberculosis (TB) in children remains a significant challenge due to its paucibacillary nature, non-specificity of symptoms and suboptimal sensitivity of available diagnostic methods. In young children particularly, it is difficult to obtain high-quality sputum specimens for testing, with this group the least likely to be diagnosed, while most at risk of severe disease. The World Health Organization (WHO) has prioritized research into rapid biomarker-based tests for TB using easily obtainable non-sputum samples, such as saliva. However, the role of biomarkers in saliva for diagnosing TB in children has not been fully explored. In this mini-review, we discuss the value of saliva as a diagnostic specimen in children given its ready availability and non-invasive nature of collection, and review the literature on the use of host-based biomarkers in saliva for diagnosing active pulmonary TB in adults and children. Based on available data from adult studies, we highlight that combinations of cytokines and other proteins show promise in reaching WHO-endorsed target product profiles for new TB triage tests. Given the lack of pediatric research on host biomarkers in saliva and the differing immune response to TB infection between children and adults, we recommend that pediatric studies are now performed to discover and validate salivary host biosignatures for diagnosing pulmonary TB in children. Future directions for pediatric saliva studies are discussed, with suggestions for technologies that can be applied for salivary biomarker discovery and point-of-care test development.