RE: Contribution of Fecal Calprotectin and Fecal Immunochemical Tests to the Evaluation of Patients with Ulcerative Colitis.

Cite this article as: Hu T, Zhang Z, Song F, Zhang W, Yang J. RE: Contribution of fecal calprotectin and fecal immunochemical tests to the evaluation of patients with ulcerative colitis. Turk J Gastroenterol. 2024;35(6):511.

Gas Chromatography-Sensor System Aids Diagnosis of Inflammatory Bowel Disease, and Separates Crohn's from Ulcerative Colitis, in Children.

The diagnosis of inflammatory bowel disease (IBD) in children and the need to distinguish between subtypes (Crohn's disease (CD) and ulcerative colitis (UC)) requires lengthy investigative and invasive procedures. Non-invasive, rapid, and cost-effective tests to support these diagnoses are needed. Faecal volatile organic compounds (VOCs) are distinctive in IBD. VOC profiles can be rapidly determined using a gas chromatography-sensor device (OdoReader©). In an inception-cohort of children presenting with suspected IBD, we directly compared the diagnostic fidelity of faecal calprotectin (FCP, a non-specific protein marker of intestinal inflammation) with OdoReader© VOC profiles of children subsequently diagnosed with IBD with matched controls diagnosed with other gastrointestinal conditions. The OdoReader© was 82% (95% confidence interval 75-89%) sensitive and 71% (61-80%) specific but did not outperform FCP (sensitivity 93% (77-99%) and specificity 86% (67-96%); 250 µg/g FCP cut off) in the diagnosis of IBD from other gastrointestinal conditions when validated in a separate sample from the same cohort. However, unlike FCP and better than other similar technologies, the OdoReader© could distinguish paediatric CD from UC (up to 88% (82-93%) sensitivity and 80% (71-89%) specificity in the validation set) and justifies further validation in larger studies. A non-invasive test based on VOCs could help streamline and limit invasive investigations in children.

Markers of Intestinal Permeability and Inflammation in Enterally Fed Children with Cerebral Palsy.

Cerebral palsy (CP) results in non-progressive damage to the central nervous system, leading to functional disorders of the gastrointestinal tract and requiring enteral nutrition via gastrostomy in some patients. The aim of the study was to assess the impact of enteral nutrition on intestinal inflammation expressed by stool calprotectin and intestinal permeability determined by fecal zonulin and IFABP, and to determine whether CP affects these parameters. The study group consisted of 30 children with CP, fed enterally (Cerebral Palsy Enteral Nutrition-CPEN), and two reference groups: 24 children with CP, fed orally with a standard diet (CPC-Cerebral Palsy Controls) and 24 healthy children (HC-healthy controls). The differences between these groups and between the combined CP groups (CPG and CPEN + CPC) and HC were analyzed. Fecal zonulin, calprotectin, and intestinal fatty acid-binding protein 2 (IFABP2) levels were determined by ELISA. The concentrations of fecal calprotectin and zonulin were significantly higher in the CPEN group than in the CPC group (p = 0.012, p = 0.025). When comparing the CPG (n = 53) with the HC group (n = 24), statistically significant differences were observed for calprotectin (p = 0.000018, higher in the CPG) and IFABP (p = 0.021, higher in HC). Enteral nutrition was associated in our cohort with increased fecal calprotectin and zonulin. Children with cerebral palsy presented with increased fecal calprotectin but not increased intestinal permeability expressed by stool zonulin.

Contribution of Fecal Calprotectin and Fecal Immunochemical Tests to the Evaluation of Patients with Ulcerative Colitis.

Cite this article as: Yakut A. Contribution of fecal calprotectin and fecal immunochemical tests to the evaluation of patients with ulcerative colitis. Turk J Gastroenterol. 2024;35(6):509-510.

Relationship between oral hypofunction and salivary biomarkers in older adults: a cross-sectional study.

BACKGROUND: Oral health problems have increased among older adults. Oral hypofunction is characterized by seven signs and symptoms: oral uncleanness, oral dryness, decline in occlusal force, decline in the movement function of the tongue and lips, decline in tongue pressure, decline in masticatory function, and decline in swallowing function, the latter being a significant risk factors for oral frailty. Recent research has suggested that salivary biomarkers can be used to assess not only oral diseases, including dental caries and periodontitis, but also systemic diseases, such as cancer and diabetes mellitus. This cross-sectional study investigated the relationship between oral hypofunction and the levels of salivary biomarkers. METHODS: In total, 116 patients, aged 65 years or older, were included in this cross-sectional study. If three or more signs or symptoms in seven kinds of tests met the criteria of each test, oral hypofunction was diagnosed. The levels of biomarkers in the saliva collected from the patients were analyzed using an enzyme-linked immunosorbent assay. RESULTS: In total, 63.8% of patients were diagnosed with oral hypofunction. Multivariable linear regression analysis showed that calprotectin levels in the saliva were significantly related to oral moisture and masticatory function. Furthermore, 8-OHdG levels in saliva were associated with the movement function of the tongue and lips and oral hygiene level, and salivary AGE correlated only with the movement function of the tongue and lips. Multiple logistic regression analysis revealed that calprotectin levels in the saliva were significantly correlated with the prevalence of oral hypofunction, even after adjusting for age, sex, and periodontal status. However, none of the biomarker levels in the saliva had a significant relationship with the number of examinations outside the reference range. CONCLUSIONS: Calprotectin, 8-OHdG, and AGE levels are associated with oral hypofunction in older adults.

3D printed rectal swabs for assessing the gut microbiome, metabolome and inflammation.

Investigating the gut microbiome and metabolome frequently requires faecal samples, which can be difficult to obtain. Previous studies have shown that rectal swabs are comparable to faecal samples for analysing gut microbiota composition and key metabolites. In this study, 3D printed rectal swabs were compared with conventional flocked swabs and faecal samples, due to the potential advantages 3D printing as a technique offers for swab production and development. 16S rRNA gene sequencing, qPCR and metabolite profiling (using 1H-NMR spectroscopy) were performed on swab and faecal samples from healthy participants. Faecal calprotectin and total protein analysis were performed on samples from inflammatory bowel disease (IBD) patients. There were no significant differences between both swab types and faecal samples when assessing key measures of alpha and beta diversity, and differences in the abundance of major phyla. There was a strong correlation between both swab types and faecal samples for all combined metabolites detected by NMR. In IBD patients, there was no significant difference in faecal calprotectin and total protein levels between both swab types and faecal samples. These data lead us to conclude that 3D printed swabs are equivalent to flocked swabs for the analysis of the gut microbiome, metabolome and inflammation.

Lipopolysaccharide-binding protein in Crohn's disease patients: a promising noninvasive biomarker monitoring disease activity.

BACKGROUND: Following STRIDE-II recommendations, the discovery of novel noninvasive biomarkers, beyond the use of C-reactive protein (CRP) and fecal calprotectin, remains a medical need to further improve the monitoring of patients with inflammatory bowel disease (IBD). This study aims to evaluate the potential of serum lipopolysaccharide-binding protein (LBP) in monitoring IBD activity. METHODS: This retrospective cross-sectional study included 69 IBD patients (43 Crohn's disease and 26 ulcerative colitis) and 82 controls. Serum LBP levels were measured by ELISA. Clinical, biological and endoscopic parameters were analyzed for IBD patients with no reports of missing data. Statistical tests, including nonparametric tests and receiver operating characteristic (ROC) curve analysis, were used to evaluate the diagnostic accuracy of LBP. RESULTS: IBD patients displayed a significantly higher LBP median [29.6 µg/ml (19.8-38.8) in Crohn's disease and 22.8 (13.7-38.8) in ulcerative colitis] than controls [5.8 (4.7-7.3), P  < 0.001] with little overlapping distributions. In Crohn's disease patients, LBP levels gradually increased with endoscopic activity scores demonstrating a 1.7-fold rise in active patients compared to remitter patients ( P  = 0.02). LBP level exhibited a positive correlation with CRP ( ρ  = 0.75, P  < 0.001) as well as fecal calprotectin ( ρ  = 0.42, P  < 0.01), both of which further increased when excluding cases that did not match endoscopic activity. CONCLUSION: LBP might be a promising noninvasive biomarker for monitoring disease activity, especially in Crohn's disease patients. In clinical situations where current biomarkers lack sensitivity, LBP could be discriminative and help filling the gap for reliable therapeutic decisions.

[Value of calprotectin S100 A8/A9 in predicting the severity of Mycoplasma pneumoniae pneumonia in children]. / 钙卫蛋白S100 A8/A9å¯¹è‚ºç‚Žæ”¯åŽŸä½“è‚ºç‚Žæ‚£å„¿ç— æƒ ä¸¥é‡ç¨‹åº¦çš„é¢„æµ‹ä»·å€¼.

OBJECTIVES: To investigate the role of calprotectin S100 A8/A9 complex in evaluating the condition of children with severe Mycoplasma pneumoniae pneumonia (SMPP). METHODS: A prospective study was conducted among 136 children with Mycoplasma pneumoniae pneumonia (MPP) and 30 healthy controls. According to the severity of the condition, the children with MPP were divided into mild subgroup (40 children) and SMPP subgroup (96 children). The levels of S100 A8/A9 complex and related inflammatory factors were compared between the MPP group and the healthy control group, as well as between the two subgroups of MPP. The role of S100 A8/A9 in assessing the severity of MPP was explored. RESULTS: The MPP group had a significantly higher level of S100 A8/A9 than the healthy control group, with a significantly greater increase in the SMPP subgroup (P<0.05). The multivariate logistic regression analysis showed that the increases in serum C reactive protein (CRP) and S100A8/A9 were closely associated with SMPP (P<0.05). The receiver operating characteristic (ROC) curve analysis showed that the combined measurement of serum S100 A8/A9 and CRP had an area under the ROC curve of 0.904 in predicting SMPP, which was significantly higher than the AUC of S100 A8/A9 or CRP alone (P<0.05), with a specificity of 0.718 and a sensitivity of 0.952. CONCLUSIONS: S100 A8/A9 is closely associated with the severity of MPP, and the combination of S100 A8/A9 with CRP is more advantageous for assessing the severity of MPP in children.

Leveraging existing mid-end ultrasound machine for point-of-care intestinal ultrasound in low-resource settings: Prospective, real-world impact on clinical decision-making.

BACKGROUND: Point-of-care ultrasound (POCUS) has transformed inflammatory bowel disease (IBD) management, but the cost to purchase high-end equipment can be prohibitive. AIM: To assess prospectively the feasibility of POCUS using pre-existing mid-end ultrasound equipment without incurring additional cost. METHODS: Consecutive IBD patients underwent POCUS with or without faecal calprotectin (FCP) using a mid-end ultrasound machine. If POCUS with or without FCP could not guide management, we performed additional ileocolonoscopy or cross-sectional imaging. We evaluated the impact of POCUS on IBD management and its correlation with ileocolonoscopy or cross-sectional imaging. We analysed pregnant, paediatric and post-operative patients separately. RESULTS: Among 508 patients with IBD, we analysed 419 (60.4% Crohn's disease [CD]; 61.3% male, age [years]: 36 [18-78]) undergoing 556 POCUS sessions. POCUS with or without FCP independently influenced clinical management in 42.8% of patients with CD and 49.7% with ulcerative colitis (UC). POCUS helped avoid colonoscopy in 51.4% of patients with CD and 51.8% with UC, and cross-sectional imaging in 38.1% of suspected active small bowel CD. In patients with additional diagnostics, POCUS-based decisions remained unchanged in 81.2% with CD and 85% with UC. Sensitivity and specificity of POCUS compared to ileocolonoscopy were 80% and 94.4% for CD and 80.8% and 92.8% for UC, respectively. Sensitivity and specificity compared to cross-sectional imaging were 87.2% and 87.5%, respectively. CONCLUSION: POCUS using existing mid-end ultrasound equipment in low-resource settings influenced IBD clinical decision-making with excellent accuracy, often avoiding colonoscopy and cross-sectional imaging.

Quantum Medicine and Irritable Bowel Syndrome-Associated Chronic Low-Back Pain: A Pilot Observational Study on the Clinical and Bio-Psycho-Social Effects of Bioresonance Therapy.

Background and Objectives: Irritable bowel syndrome (IBS) is an invasive and potentially disabling syndrome characterized by a multitude of symptoms capable of reducing the quality of life of patients. Among the most disabling symptoms of IBS is certainly physical pain, which manifests itself mainly at the abdominal level but can also appear in other areas of the body, particularly in the form of chronic low-back pain (CLBP). Among the non-invasive methods of treating organ-specific pathologies and organ-related musculoskeletal problems, the use of Bioresonance Therapy (BT)-based on the administration of self-modulating Extremely Low-Frequency Electromagnetic Fields, capable of determining a rebalance of bio-electrical and metabolic activity in the presence of various functional alterations-is currently gaining acceptance. Therefore, we decided to monitor results obtained from patients suffering from IBS and CLBP subjected to a cycle of treatments with BT. Materials and Methods: We monitored 20 patients (12 women and 8 men, average age of 51 years) suffering from CLBP and other visceral symptoms related to IBS. Patients were monitored through the use of the Bristol Stool Form Scale (BSFS), the Fecal Calprotectin test and the Short-Form Health Survey 36 (SF-36), collected before (T0) and after (T1) the execution of the cycle of treatments. They undertook a treatment protocol consisting of eight sessions of BT carried out over about a month. Results: At the end of the treatments with BT, it was possible to observe a general and significant improvement in all the parameters observed, as well as a close inversely proportional correlation between the Calprotectin values detected and the quality of life experienced by the patients in relation to their perceived IBS symptoms. Conclusions: Overall, our pilot study would seem to suggest a potential beneficial effect of BT in modulating organic and musculoskeletal symptoms derived from IBS.

Assessing seasonal variations of biomarkers in inflammatory bowel disease.

OBJECTIVE: Inflammatory bowel diseases are chronic pathologies characterized by a complex interplay of genetic and environmental factors, as well as aberrant immune responses. This study aimed to investigate inflammation markers' seasonality and association with disease exacerbation episodes in patients with Crohn's disease and ulcerative colitis. METHODS: 284 patients were classified based on clinical, endoscopic, and histopathological criteria. Systemic inflammation was evaluated using C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and chitotriosidase, while fecal calprotectin was measured to assess intestinal inflammation. Serum vitamin D levels and the seasonality of an activity score that combines several clinical and biological parameters were also evaluated. RESULTS: The peak number of patients reporting endoscopic activity occurred in autumn for Crohn's disease (82%) and spring for ulcerative colitis (95%). Regarding histological activity, spring saw the highest number of patients for both diseases (72% for Crohn's disease; 87% for ulcerative colitis). Most of the inflammatory markers exhibited lower values during winter. Systemic inflammatory markers follow a slightly different trend than fecal calprotectin and differ in the two pathologies. The maximum values of intestinal inflammation were observed in autumn for Crohn's disease (784 µg/g) and in spring for ulcerative colitis (1269 µg/g). Serum vitamin D concentrations were consistently low throughout the year. Statistical analysis revealed differences between the seasons for CRP and ESR (P < 0.05). CONCLUSION: The evolution of flares and inflammatory markers in Crohn's disease and ulcerative colitis displayed distinct seasonal patterns. Systemic inflammation did not consistently parallel intestinal inflammation.

Fecal calprotectin and endoscopic scores: The cornerstones in clinical practice for evaluating mucosal healing in inflammatory bowel disease.

Managing inflammatory bowel disease (IBD) is becoming increasingly complex and personalized, considering the advent of new advanced therapies with distinct mechanisms of action. Achieving mucosal healing (MH) is a pivotal therapeutic goal in IBD management and can prevent IBD progression and reduce flares, hospitalization, surgery, intestinal damage, and colorectal cancer. Employing proactive disease and therapy assessment is essential to achieve better control of intestinal inflammation, even if subclinical, to alter the natural course of IBD. Periodic monitoring of fecal calprotectin (FC) levels and interval endoscopic evaluations are cornerstones for evaluating response/remission to advanced therapies targeting IBD, assessing MH, and detecting subclinical recurrence. Here, we comment on the article by Ishida et al Moreover, this editorial aimed to review the role of FC and endoscopic scores in predicting MH in patients with IBD. Furthermore, we intend to present some evidence on the role of these markers in future targets, such as histological and transmural healing. Additional prospective multicenter studies with a stricter MH criterion, standardized endoscopic and histopathological analyses, and virtual chromoscopy, potentially including artificial intelligence and other biomarkers, are desired.

Diagnostic potential of various laboratory tests for Irritable Bowel Syndrome (IBS): A systematic review.

Objective: To identify possible tests along with their accuracies that may be used to diagnose irritable bowel syndrome. METHODS: The systematic review comprised literature search on Cochrane Library, PubMed, Science Direct and Elsevier databases for randomised controlled trials and cohort studies conducted from January 1, 2015, to December 31, 2022, using appropriate key words and Boolean operators. Focus was kept on studies that reported irritable bowel syndrome diagnosis as the primary outcome. The risk of bias was assessed using quality assessment, data abstraction, and synthesis version 2. RESULTS: Of the 2,798 studies initially identified, 10(0.35%) were analysed in detail. Of them, 4(40%) used enzyme-linked immunosorbent assay kits to test for anti-cytolethal distending toxin B and anti-vinculin levels, 2(20%) used the kits for serum cytokine profiling and serum calprotectin levels, and 4(40%) used either magnetic resonance imaging scans, faecal metabolic profiling, intestinal biopsy analysis with immunostaining or polymerase chain reaction for differential transferribonucleic acid-derived small ribonucleic acid. Out of the 4(40%) studies on anti-cytolethal distending toxin B and anti-vinculin levels, optical densities >1.56 and >1.60 recorded 100% specificity for irritable bowel syndrome with diarrhoea, but sensitivity was 22%. In contrast, rectal biopsies for cell densities of somatostatin and peptide YY showed high sensitivity and specificity for irritable bowel syndrome ranging 80-90%. Conclusion: Enzyme-linked immunosorbent assay testing for anti-cytolethal distending toxin B and anti-vinculin as well as rectal biopsies for cell densities could be potential diagnostic tests for irritable bowel syndrome.

Assessing anorectal function in patients with recurrent ulcerative colitis.

PURPOSE: Ulcerative colitis (UC) is an inflammatory bowel disease with an unclear etiology that can lead to irreversible changes in distal colonic function in chronic patients. This study investigated anorectal function in recurrent UC patients and identified influencing factors. METHODS: This prospective study enrolled 33 recurrent UC patients and 40 newly diagnosed patients from January 2019 to December 2022. Data collection included clinical records, scores, and anorectal function assessments. Regression analyses were used to identify factors impacting anorectal function. RESULTS: Recurrent UC patients had higher baseline CRP and fecal calprotectin levels, increased anxiety and depression, and more severe fecal incontinence. They also had lower BMIs, serum Hb and albumin (ALB) levels, and Inflammatory Bowel Disease Questionnaire scores than did initial-onset UC patients. Multivariate linear regression analysis revealed that long disease duration (coef. - 0.376, P < 0.001) and high fecal calprotectin level (coef. - 0.656, P < 0.001) independently influenced the initial sensation threshold in recurrent UC patients. Additionally, high fecal calprotectin (coef. - 0.073, P = 0.013) and high Zung Self-Rating Anxiety Scale score (coef. - 0.489, P = 0.001) were identified as two independent determinants of the defecation volume threshold. For the defecation urgency threshold, the independent factors included high disease duration (coef. - 0.358, P = 0.017) and high fecal calprotectin level (coef. - 0.499, P = 0.001). Similarly, the sole independent factor identified for the maximum capacity threshold was high fecal calprotectin (coef. - 0.691, P = 0.001). CONCLUSION: Recurrent UC patients had increased rectal sensitivity and compromised anorectal function, which significantly impacted quality of life. Proactively managing the disease, reducing UC relapses, and addressing anxiety are effective measures for improving anorectal function in these patients.

Effectiveness of Switching to Subcutaneous Infliximab in Ulcerative Colitis Patients Experiencing Intravenous Infliximab Failure.

Background/Aims: Studies on elective switching to the subcutaneous (SC) formulation of infliximab revealed comparable efficacy and safety and higher infliximab level than those exhibited by intravenous (IV) infliximab. However, no studies have reported on the effectiveness of SC switching in ulcerative colitis (UC) patients who experienced IV infliximab failure during maintenance treatment. Methods: This retrospective study included UC patients who had been switched to SC infliximab because of IV infliximab failure, between January 2021 and January 2023. Group A was defined as having clinically and biochemically active UC (secondary loss of response), and group B consisted of patients with stable symptoms but biochemically active UC. Results: Twenty-three patients met the inclusion criteria: 15 in group A and eight in group B. The serum infliximab levels significantly increased after SC switching in both groups. The electively switched group also exhibited increased infliximab levels after SC switching. Patients in group A showed improved partial Mayo score with a significant decrease in fecal calprotectin and C-reactive protein after switching. In group B, the fecal calprotectin level significantly decreased without clinical relapse after switching. A high proportion of patients (≥80%) in both groups achieved clinical and/or biochemical responses at the last follow-up. During the follow-up period, only two patients in group A discontinued SC infliximab, and only one complained of severe injection site reaction. Conclusions: In UC patients who experience IV infliximab failure during maintenance treatment, switching to SC infliximab may be a promising option because of better efficacy and safety.

Peri-implant phenotype, calprotectin and MMP-8 levels in cases diagnosed with peri-implant disease.

OBJECTIVES: The purpose of this prospective cohort study is to evaluate the effect of peri-implant phenotype (PPh) on the severity of peri-implant diseases and the results of non-surgical mechanical treatment (NSMT), along with calprotectin (CLP) and MMP-8(matrix metalloproteinase-8) levels. MATERIALS AND METHODS: 77 implants from 39 patients were included. The implants were categorized Group-1(peri-implant mucositis), Group-2(peri-implantitis).Baseline (0. Month-PrT) clinical parameters (PD, GI, PI, BOP, CAL) and radiographic bone loss were documented, and peri-implant crevicular fluid (PICF) samples were collected. Various intruments and methodologies were employed to assess PPh components (mucosa thickness, supracrestal tissue height, keratinized mucosa) and peri-implant attached mucosa (AM). NSMT was applied to diseased implant sites. All clinical parameters were reassessed again by taking PICF samples at the 6th month-after treatment (PT). In PICF samples obtained from both groups, MMP-8 and CLP levels were evaluated using the ELISA test. RESULTS: PrT-PD,PrT-GI,PrT-CAL and PrT-BOP percentage values in Group-2 were significantly higher than Group-1.PrT-PD,PrTPI scores are significantly higher in thin biotype implants. All components of the PPh and AM were significantly lower in thin biotype. Intra-group time-dependent changes of MMP-8 and CLP were significant in both groups (p < 0.05). When the relationship between thin and thick biotype and biochemical parameters was evaluated, the change in PrT-PT didn't show a significant difference (p > 0.05). CONCLUSIONS: PPh plays a role in influencing the severity of peri-implant diseases. However, the impact of phenotype on NSMT outcomes was similar in both groups. CLINICAL RELEVANCE: The PPh should be considered when planning implant surgery.

Dual burden of infectious and chronic disease in low-resource U.S. communities: examining relationships between infection, adiposity, and inflammation.

BACKGROUND: Rising global obesity rates are linked with inflammation and associated morbidities. These negative outcomes are generally more common in low-resource communities within high-income countries; however, it is unclear how frequent infectious disease exposures in these settings may influence the relationship between adiposity and inflammation. AIM: We test associations between adiposity measures and distinct forms of inflammation among adults (n = 80) living in low-resource U.S. communities experiencing high levels of obesity and pathogen exposure. SUBJECTS AND METHODS: Adiposity measures included BMI and percent body fat. Inflammation measures included systemic inflammation (C-reactive protein [CRP]) and localised intestinal inflammation (faecal calprotectin [FC]). The relationship between a condition characterised by elevated inflammation (Helicobacter pylori infection) and adiposity was also considered. RESULTS: Adiposity was not significantly related to FC concentration. However, both adiposity measures were positively related with odds of CRP elevation and H. pylori infection was associated with significantly lower adiposity measures (all p < 0.05). CONCLUSION: For this disadvantaged U.S. sample, the association between adiposity and inflammation varies by the systemic/localised nature of inflammation and the likely underlying cause of inflammation. Defining these associations will improve understanding of how rising obesity rates shape long-term health inequities, with implications for more effective intervention design.

Elevated fecal calprotectin is associated with gut microbial dysbiosis, altered serum markers and clinical outcomes in older individuals.

Fecal calprotectin is an established marker of gut inflammation in inflammatory bowel disease (IBD). Elevated levels of fecal calprotectin as well as gut microbial dysbiosis have also been observed in other clinical conditions. However, systemic and multi-omics alterations linked to elevated fecal calprotectin in older individuals remain unclear. This study comprehensively investigated the relationship between fecal calprotectin levels, gut microbiome composition, serum inflammation and targeted metabolomics markers, and relevant lifestyle and medical data in a large sample of older individuals (n = 735; mean age ± SD: 68.7 ± 6.3) from the TREND cohort study. Low (0-50 µg/g; n = 602), moderate (> 50-100 µg/g; n = 64) and high (> 100 µg/g; n = 62) fecal calprotectin groups were stratified. Several pro-inflammatory gut microbial genera were significantly increased and short-chain fatty acid producing genera were decreased in high vs. low calprotectin groups. In serum, IL-17C, CCL19 and the toxic metabolite indoxyl sulfate were increased in high vs. low fecal calprotectin groups. These changes were partially mediated by the gut microbiota. Moreover, the high fecal calprotectin group showed increased BMI and a higher disease prevalence of heart attack and obesity. Our findings contribute to the understanding of fecal calprotectin as a marker of gut dysbiosis and its broader systemic and clinical implications in older individuals.

Development of Luminescent Biosensors for Calprotectin.

Calprotectin, a metal ion-binding protein complex, plays a crucial role in the innate immune system and has gained prominence as a biomarker for various intestinal and systemic inflammatory and infectious diseases, including inflammatory bowel disease (IBD) and tuberculosis (TB). Current clinical testing methods rely on enzyme-linked immunosorbent assays (ELISAs), limiting accessibility and convenience. In this study, we introduce the Fab-Enabled Split-luciferase Calprotectin Assay (FESCA), a novel quantitative method for calprotectin measurement. FESCA utilizes two new fragment antigen binding proteins (Fabs), CP16 and CP17, that bind to different epitopes of the calprotectin complex. These Fabs are fused with split NanoLuc luciferase fragments, enabling the reconstitution of active luciferase upon binding to calprotectin either in solution or in varied immobilized assay formats. FESCA's output luminescence can be measured with standard laboratory equipment as well as consumer-grade cell phone cameras. FESCA can detect physiologically relevant calprotectin levels across various sample types, including serum, plasma, and whole blood. Notably, FESCA can detect abnormally elevated native calprotectin from TB patients. In summary, FESCA presents a convenient, low-cost, and quantitative method for assessing calprotectin levels in various biological samples, with the potential to improve the diagnosis and monitoring of inflammatory diseases, especially in at-home or point-of-care settings.