Urinary Peptides Research Articles

Urinary proteomic signature of mineralocorticoid receptor antagonism by spironolactone: evidence from the HOMAGE trial

Abstract Background Heart failure (HF) is characterised by collagen deposition. Urinary proteomic profiling (UPP) detects many sequenced peptides, for >70% derived from collagens. Purpose UPP and serum fibrosis markers were analysed together in patients at risk of HF with as objective to generate insights into the antifibrotic action of spironolactone. Methods In the open-label HOMAGE trial, patients were randomised to usual therapy combined or not with spironolactone 25-50 mg/d and followed for 9 months (n=290; 23.8% women; median age: 73 years). UPP was done by capillary electrophoresis coupled with mass spectrometry; 1498 urinary peptides with detectable signal in ≥30% of patients were analysed. Serum markers of COL1A1 synthesis (PICP and PICP/CITP) were measured. After rank normalisation of the biomarker distributions, between-group differences in their changes were assessed by multivariable-adjusted models. Correlations between the changes in urinary peptides and in serum PICP and PICP/CITP were compared between groups using Fisher Z transform. Results Among all the urinary peptides, only the changes in collagen fragments remained significantly different (p<0.05) between randomisation groups after accounting for baseline levels, covariables and multiple testing. Compared to the control group, spironolactone reduced 16 of 27 collagen-derived urinary peptides. From baseline to 9 months, serum PICP and the PICP/CITP ratio decreased from 79.0 to 75.4 µg/L and from 21.3 to 18.3, respectively (p≤0.0129), reflecting decreased COL1A1 synthesis. Spironolactone did not affect the correlations between changes in urinary COL1A1 fragments and the serum fibrosis markers. Conclusions Spironolactone downregulated urinary collagen-derived peptides, probably by shrinking the body-wide pool of collagens. Spironolactone did not affect the interaction between urinary and serum fibrosis markers, suggesting that collagen scaffolding is maintained, thereby explaining why some urinary collagen fragments increased. Combining urinary and serum fibrosis biomarkers opens new avenues for discovery of antifibrotic drugs and refines insight in the action of antifibrotic drugs.Figure 1Figure 2

OSTEO18, a novel urinary proteomic signature, associated with osteoporosis in heart transplant recipients

Abstract Background Immunosuppressive treatment in heart transplant (HTx) recipient causes osteoporosis. The urinary proteomic profile (UPP) includes peptide fragments derived from the bone extracellular matrix. Purpose Study aims were to develop and validate a multidimensional UPP biomarker for osteoporosis in HTx patients from single sequenced urinary peptides identifying the parent proteins. Methods A single-center HTx cohort was analyzed. Urine samples were measured by capillary electrophoresis coupled with mass spectrometry. Cases with osteoporosis and matching controls were randomly selected from all available 389 patients. In derivation case-control dataset, 1576 sequenced peptides detectable in ≥30% of patients. Applying statistical analysis on these, an 18-peptide multidimensional osteoporosis UPP biomarker (OSTEO18) was generated by support vector modeling. The 2 replication datasets included 118 and 94 patients. For further validation, the whole cohort was analyzed. Statistical methods included logistic regression and receiver operating characteristic curve (ROC) analysis. Results In derivation dataset, the AUC, sensitivity and specificity of OSTEO18 were 0.83 (95% CI: 0.76-0.90), 74.3% and 87.1%, respectively. In replication datasets, results were confirmatory. In the whole cohort (154 osteoporotic patients [39.6%]), the ORs for osteoporosis increased (p < 0.0001) across OSTEO18 quartiles from 0.39 (95% CI: 0.25-0.61) to 3.14 (2.08-4.75). With full adjustment for known osteoporosis risk factors, OSTEO18 improved AUC from 0.708 to 0.786 (p = 0.0003) for OSTEO18 categorized (optimized threshold: 0.095) and to 0.784 (p = 0.0004) for OSTEO18 as continuously distributed classifier. Conclusion OSTEO18 is a clinically meaningful novel biomarker indicative of osteoporosis in HTx recipients and is being certified as in-vitro diagnostic.

Hydroxyprolyl-Glycine in 24 H Urine Shows Higher Correlation with Meat Consumption than Prolyl-Hydroxyproline, a Major Collagen Peptide in Urine and Blood.

Background. Urinary collagen peptides, the breakdown products of endogenous collagen, have been used as biomarkers for various diseases. These non-invasive biomarkers are easily measured via mass spectrometry, aiding in diagnostics and therapy effectiveness. Objectives. The objective of this study was to investigate the effects of consuming collagen-containing meat on collagen peptide composition in human blood and urine. Methods. Ten collagen peptides in 24 h urine were quantified. Results. Prolyl-hydroxyproline (Pro-Hyp) was the most abundant peptide. Except for hydroxyprolyl-glycine (Hyp-Gly), levels of other minor collagen peptides showed high correlation coefficients with Pro-Hyp (r = 0.42 vs. r > 0.8). Notably, 24 h urinary Hyp-Gly showed a correlation coefficient of r = 0.72 with meat consumption, significantly higher than the coefficient for Pro-Hyp (r = 0.37). Additionally, the levels of Pro-Hyp and Hyp-Gly in the blood of seven young women participants increased similarly after consuming fish meat, while before ingestion, only negligible amounts of Hyp-Gly were present. To examine which peptides are generated by the degradation of endogenous collagen, mouse skin was cultured. The amount of Pro-Hyp released from the skin was approximately 1000-fold higher than that of Hyp-Gly. Following consumption of collagen-containing meat, both Pro-Hyp and Hyp-Gly are released in blood and excreted into urine, although Pro-Hyp is primarily generated from endogenous collagen even under physiological conditions. Conclusions. Therefore, in 24 h urine samples, the non-negligible fraction of Pro-Hyp is contributed by endogenous collagen, making 24 h urine Hyp-Gly level a potential biomarker for evaluating meat consumption on the day.

Urinary and fecal gluten immunogenic peptides’ detection to monitor gluten challenge in patients with suspected celiac disease

Urinary and fecal gluten immunogenic peptides’ detection to monitor gluten challenge in patients with suspected celiac disease

Urinary proteomic signature of mineralocorticoid receptor antagonism by spironolactone: evidence from the HOMAGE trial

ObjectiveHeart failure (HF) is characterised by collagen deposition. Urinary proteomic profiling (UPP) followed by peptide sequencing identifies parental proteins, for over 70% derived from collagens. This study aimed to refine...

Mortality Risk and Urinary Proteome Changes in Acute COVID-19 Survivors in the Multinational CRIT-COV-U Study.

Survival prospects following SARS-CoV-2 infection may extend beyond the acute phase, influenced by various factors including age, health conditions, and infection severity; however, this topic has not been studied in detail. Therefore, within this study, the mortality risk post-acute COVID-19 in the CRIT-COV-U cohort was investigated. Survival data from 651 patients that survived an acute phase of COVID-19 were retrieved and the association between urinary peptides and future death was assessed. Data spanning until December 2023 were collected from six countries, comparing mortality trends with age- and sex-matched COVID-19-negative controls. A death prediction classifier was developed and validated using pre-existing urinary peptidomic datasets. Notably, 13.98% of post-COVID-19 patients succumbed during the follow-up, with mortality rates significantly higher than COVID-19-negative controls, particularly evident in younger individuals (<65 years). These data for the first time demonstrate that SARS-CoV-2 infection highly significantly increases the risk of mortality not only during the acute phase of the disease but also beyond for a period of about one year. In our study, we were further able to identify 201 urinary peptides linked to mortality. These peptides are fragments of albumin, alpha-2-HS-glycoprotein, apolipoprotein A-I, beta-2-microglobulin, CD99 antigen, various collagens, fibrinogen alpha, polymeric immunoglobulin receptor, sodium/potassium-transporting ATPase, and uromodulin and were integrated these into a predictive classifier (DP201). Higher DP201 scores, alongside age and BMI, significantly predicted death. The peptide-based classifier demonstrated significant predictive value for mortality in post-acute COVID-19 patients, highlighting the utility of urinary peptides in prognosticating post-acute COVID-19 mortality, offering insights for targeted interventions. By utilizing these defined biomarkers in the clinic, risk stratification, monitoring, and personalized interventions can be significantly improved. Our data also suggest that mortality should be considered as one possible symptom or a consequence of post-acute sequelae of SARS-CoV-2 infection, a fact that is currently overlooked.

O67 URINARY PROTEOMIC PROFILING REVEALS MOLECULAR CUES UNDERLYING HIGHER HYPERTENSION SUSCEPTIBILITY IN BLACKS THAN WHITES

Background and Objective: Compared with Whites, Blacks are more prone to hypertension and salt-sensitivity. The objective was to investigate whether sequenced urinary peptide fragments derived from proteins with a key role in cardiovascular or renal structure or function have different levels in sub-Saharan Blacks compared with Whites. Methods: This individual-participant meta-analysis included individuals enrolled in African-PREDICT (476 Blacks and 483 Whites), FLEMENGHO (720 Whites), PROVALID-Austria (467 Whites) and UPRIGHT-HTM (106 Nigerian Blacks and 61 Polish and Slovenian Whites). Urinary peptides were quantified by capillary electrophoresis combined with mass spectrometry. Results: Among 2313 participants (49.7% women), median age was 40.9 years. Of 513 urinary peptides with 70% prevalence, 300 had Bonferroni-corrected significantly different levels among Black and White South Africans sharing the same environment. Analyses contrasting 582 Blacks vs 1731 Whites, sub-Saharan Blacks (582) vs European Whites (1248) replicated the findings. Combining these results with information from public databases, we identified COL4A1, COL4A2, CD99, FAT1, FGA, FXYD2, MGP, MYOCD, PCDH7, PROC, and UMOD as most likely candidates underlying the different susceptibility to hypertension and salt sensitivity between Blacks and Whites. The most relevant enriched pathways were related to hemostasis, platelet activity, collagens and biology of the extracellular matrix, and protein digestion and absorption. Disease Ontology terms comprised small-vessel disease and coronary and macrovascular atherosclerotic disease. Conclusions: MGP and MYOCD being involved in cardiovascular function, FGA in clot formation, FYXD2 and UMOD in salt homeostasis, and COL4A1 and COL4A2 as major component of the glomerular basement membrane are proteins deserving further exploration in molecular and human studies as potential targets for intervention to reduce the excess hypertension risk and associated complications in Blacks.

Urinary opioid peptides in children with autism spectrum disorders. A Pilot Study

BACKGROUND: Circulating β-casomorphins (BCM) and gluten exorphins (GE), which are exogenous opioid peptides originating from bovine milk protein casein and cereal protein gluten, respectively, have been proposed as potential trigger factor to symptoms observed in children with autism. OBJECTIVE: Given the debate surrounding the detectability of these opioid peptides in body fluids, particularly using highly sensitive and specific mass spectrometry (HPLC-MS) techniques, we aimed to investigate their presence in urine samples of autistic subjects. METHODS: We employed an HPLC-MS method for peptide detection. RESULTS: The presence of several BCMs and GEs in the urine of both autistic children (ASD) and healthy controls (HC) was documented. The detection of dietary opioid peptides even at very low concentrations underscores the sensitivity of this novel HPLC-MS method. BCM-8 was more often detected in the ASD group compared to the HC group. A higher prevalence of gastrointestinal (GI) symptoms were also observed in the ASD group. CONCLUSIONS: This pilot study supports the presence of BCMs and GEs in urine samples in subjects with autism as well as healthy controls which was the main goal of this pilot study. Prolonged exposure to bovine BCMs and GEs may play a role in the manifestation of core and GI symptoms in subgroups of autism. Further research is warranted to investigate this phenomenon thoroughly.

Multiple urinary peptides are associated with hypertension: a link to molecular pathophysiology.

Hypertension is a common condition worldwide; however, its underlying mechanisms remain largely unknown. This study aimed to identify urinary peptides associated with hypertension to further explore the relevant molecular pathophysiology. Peptidome data from 2876 individuals without end-organ damage were retrieved from the Human Urinary Proteome Database, belonging to general population (discovery) or type 2 diabetic (validation) cohorts. Participants were divided based on systolic blood pressure (SBP) and diastolic BP (DBP) into hypertensive (SBP ≥140 mmHg and/or DBP ≥90 mmHg) and normotensive (SBP <120 mmHg and DBP <80 mmHg, without antihypertensive treatment) groups. Differences in peptide abundance between the two groups were confirmed using an external cohort ( n = 420) of participants without end-organ damage, matched for age, BMI, eGFR, sex, and the presence of diabetes. Furthermore, the association of the peptides with BP as a continuous variable was investigated. The findings were compared with peptide biomarkers of chronic diseases and bioinformatic analyses were conducted to highlight the underlying molecular mechanisms. Between hypertensive and normotensive individuals, 96 (mostly COL1A1 and COL3A1) peptides were found to be significantly different in both the discovery (adjusted) and validation (nominal significance) cohorts, with consistent regulation. Of these, 83 were consistently regulated in the matched cohort. A weak, yet significant, association between their abundance and standardized BP was also observed. Hypertension is associated with an altered urinary peptide profile with evident differential regulation of collagen-derived peptides. Peptides related to vascular calcification and sodium regulation were also affected. Whether these modifications reflect the pathophysiology of hypertension and/or early subclinical organ damage requires further investigation.

Systems biology and novel biomarkers for the early detection of diabetic kidney disease.

Diabetic kidney disease is the most common driver of chronic kidney disease (CKD)-associated mortality and kidney replacement therapy. Despite recent therapeutic advances (SGLT2 inhibitors, finerenone), the residual kidney and mortality risk remains high for patients already diagnosed of having CKD (i.e., estimated glomerular filtration rate &lt;60 ml/min/1.73 m2 or urinary albumin:creatinine ratio &gt;30 mg/g). The challenge for the near future is to identify patients at higher risk of developing CKD to initiate therapy before CKD develops (primary prevention of CKD) and to identify patients with CKD and high risk of progression or death, in order to intensify therapy. We now discuss recent advances in biomarkers that may contribute to identify such high-risk individuals for clinical trials of novel primary prevention or treatment approaches for CKD. The most advanced biomarker from a clinical development point of view is the urinary peptidomics classifier CKD273, that integrates prognostic information from 273 urinary peptides and identifies high risk individuals before CKD develops.

Development and Validation of a Tool for Assessing Adherence to Gluten-Free Diet in Patients With Celiac Disease.

Life-long adherence to gluten-free diet (GFD) and its assessment is essential for patients with celiac disease (CeD). We have developed and validated a tool for assessing adherence to GFD which can be used by both physicians and dietitians. Phase 1: Development, content validation, and assessment of reliability of tool. Phase 2: Validation of tool against standard dietary evaluation (SDE) (gold standard), immunoglobulin A - anti-tissue transglutaminase antibodies (IgA anti-tTG Ab), and gluten immunogenic peptides in urine. Overall, 380 biopsy-confirmed patients with CeD (derivation cohort: n = 100 [phase 1], n = 210 [phase 2] and independent validation cohort, n = 70) were recruited. Of an initial 90-point questionnaire, 84 items (Celiac Disease: Compliance Assessment Test [CD-CAT.v1]) were retained after content validation and pilot testing. In phase 1, upon administering CD-CAT.v1 on 100 patients, a comprehensive 35-item tool (CD-CAT.v2; α = 0.86) was obtained after removing items with low test-retest reliability and item-rest correlation values. In phase 2, upon administering CD-CAT.v2 on 210 patients, 22 items were removed having low correlation values (R < 0.4) with SDE. Finally, a 13-item tool (CD-CAT.v3; α = 0.84) was obtained with high criterion validity with SDE ( r = 0.806, P < 0.001), moderate convergent validity with celiac disease adherence test ( r = 0.602, P = 0.007), and moderate to weak correlation with urine gluten immunogenic peptides ( r = 0.46, P = 0.001) and IgA anti-tTG Ab ( r = 0.39, P = 0.008), respectively. The final 13-item tool also strongly correlated with SDE ( r = 0.78, P < 0.001) in an independent validation cohort of 70 patients with CeD. Principal component analysis identified 3 relevant subscales with a cumulative variance of 62%. The sensitivity and specificity of CD-CAT.v3 were 80% and 91%, respectively, with an area under curve of 0.905 with SDE. The obtained cutoff score of <19 from the receiver operating characteristic curve was further categorized as 13 = excellent, 14-18 = very good, 19-28 = average, and >28 = poor adherence to GFD. CD-CAT is a new and rapid tool for monitoring dietary adherence to GFD with high sensitivity and specificity, which can be administered by both physicians and dietitians.

Investigating and Annotating the Human Peptidome Profile from Urine under Normal Physiological Conditions.

Examining the composition of the typical urinary peptidome and identifying the enzymes responsible for its formation holds significant importance, as it mirrors the normal physiological state of the human body. Any deviation from this normal profile could serve as an indicator of pathological processes occurring in vivo. Consequently, this study focuses on characterizing the normal urinary peptidome and investigating the various catalytic enzymes that are involved in generating these native peptides in urine. Our findings reveal that 1503 endogenous peptides, corresponding to 436 precursor proteins, were consistently identified robustly in at least 10 samples out of a total of 19 samples. Notably, the liver and kidneys exhibited the highest number of tissue-enriched or enhanced genes in the analyzed urinary peptidome. Furthermore, among the catalytic types, CTSD (cathepsin D) and MMP2 (matrix metalloproteinase-2) emerged as the most prominent peptidases in the aspartic and metallopeptidases categories, respectively. A comparison of our dataset with two of the most comprehensive urine peptidome datasets to date indicates a consistent relative abundance of core endogenous peptides for different proteins across all three datasets. These findings can serve as a foundational reference for the discovery of biomarkers in various human diseases.

Long-Term Changes of Urinary Exosomal Peptide Levels After Thyroidectomy in Patients with Thyroid Cancer: A Prospective Observational Study.

The recurrence rate of thyroid cancer can be as high as 30%. The purpose of this study was to examine changes of urine exosomal peptide levels after thyroidectomy in patients with thyroid cancer to determine if levels can predict the risk of recurrence. Patients >20 years old as newly diagnosed with papillary thyroid cancer who had received a thyroidectomy were recruited. Urine samples were collected at 12 months after enrollment to the study, and 1 year later. Urine exosomes containing different peptides were identified and compared. A total of 70 patients were enrolled in the study, and were classified by the interval between surgery and enrollment: 42 patients with < 5 years between surgery and enrollment, 14 patients between 5-10 years, and 14 patients longer than 10 years. No recurrence was observed in any patient during the 2 years after enrollment. No significant differences were found in the levels of serum proteins or urine exosomal peptides between groups, or between intervals. Known risk factors for high-risk thyroid cancer had only a mild correlation with serum protein levels and urine exosomal peptides. Our study revealed the long-term basal fluctuation ranges of serum proteins and urine exosomal peptides in patients with thyroid cancer who underwent thyroidectomy. For high-risk patients after thyroidectomy, concentrations of serum proteins or urine exosomal peptides within the ranges may indicate there is a lower risk of thyroid cancer recurrence during long-term follow-up. ClinicalTrials.gov: NCT03488134.

Urinary peptide profiling for prediction of kidney disease progression in community populations: A prospective study with 6-year follow-up

Urinary peptide profiling for prediction of kidney disease progression in community populations: A prospective study with 6-year follow-up

Gluten Free Casein Free Diet for Children with Autism Spectrum Disorder – A Review

Autism Spectrum Disorder is a group of neurodevelopmental conditions characterized by social and repetitive behaviour. As per WHO it is estimated that worldwide 1 in 160 children has ASD. Based on epidemiological studies conducted over the past 50 years, the prevalence of ASD appears to be increasing globally. Delayed speech, frequent repetition of set words and phrases, no social interactions, sensory changes etc. are the main symptoms of ASD. There is no known cure for ASD, but many different approaches are used to treat the symptoms of the disorders, for example, visual aids are used to improve communication, social stories interventions are used to teach appropriate social behaviour, and medication is used to ameliorate specific symptoms like aggression. Dietary intervention as a tool for maintaining and improving physical health and wellbeing for ASD is a widely researched and discussed topic. Studies have depicted that there is a link between diet, gut epithelial changes and altered immune response in the spectrum disorders exhibited by children with Autism. A gluten-free casein-free diet is also known as the GFCF diet. It is one of several alternative treatments for children with autism. When following this strict elimination diet, all foods containing and casein are removed from the child's daily food intake. Foods that contained proteins such as gluten and casein causes hypersensitivity to children with ASD. The children cannot digest these proteins properly. This result to increase the level of urinary small peptides. These peptides bind to opioid receptors and become biologically active, which results excess of opioid and leads to an increase of the behavioural difficulties seen in the children. Dietary interventions with the exclusion of gluten, casein or both is thought to have a positive effect on behavioural symptoms because of the elevated levels of peptides seen in the urinary analyses. Since the chemical structure of gluten and casein are very similar to each other, it is very likely that having a sensitivity to one of them means having a sensitivity to both, even though one could be worse than the other. This paper provide an overview of the gluten free casein free diet and its positive and negative results of Gluten free Casein free diet on the basis of reviewing case studies.

Integration of Urinary Peptidome and Fecal Microbiome to Explore Patient Clustering in Chronic Kidney Disease.

Millions of people worldwide currently suffer from chronic kidney disease (CKD), requiring kidney replacement therapy at the end stage. Endeavors to better understand CKD pathophysiology from an omics perspective have revealed major molecular players in several sample sources. Focusing on non-invasive sources, gut microbial communities appear to be disturbed in CKD, while numerous human urinary peptides are also dysregulated. Nevertheless, studies often focus on isolated omics techniques, thus potentially missing the complementary pathophysiological information that multidisciplinary approaches could provide. To this end, human urinary peptidome was analyzed and integrated with clinical and fecal microbiome (16S sequencing) data collected from 110 Non-CKD or CKD individuals (Early, Moderate, or Advanced CKD stage) that were not undergoing dialysis. Participants were visualized in a three-dimensional space using different combinations of clinical and molecular data. The most impactful clinical variables to discriminate patient groups in the reduced dataspace were, among others, serum urea, haemoglobin, total blood protein, urinary albumin, urinary erythrocytes, blood pressure, cholesterol measures, body mass index, Bristol stool score, and smoking; relevant variables were also microbial taxa, including Roseburia, Butyricicoccus, Flavonifractor, Burkholderiales, Holdemania, Synergistaceae, Enterorhabdus, and Senegalimassilia; urinary peptidome fragments were predominantly derived from proteins of collagen origin; among the non-collagen parental proteins were FXYD2, MGP, FGA, APOA1, and CD99. The urinary peptidome appeared to capture substantial variation in the CKD context. Integrating clinical and molecular data contributed to an improved cohort separation compared to clinical data alone, indicating, once again, the added value of this combined information in clinical practice.

Nanopore Testing: A Paradigm Shift in Ovarian Cancer Screening

Nanopore Testing: A Paradigm Shift in Ovarian Cancer Screening

Performances of acute kidney injury biomarkers vary according to sex.

Before implementing individualized strategies to treat acute kidney injury (AKI), identifying clusters of patients with divergent pathophysiological mechanisms, diagnosis criteria or outcomes is of the utmost importance. Here we studied sex-related molecular mechanisms in cardiac bypass (CBP) surgery patients developing AKI. We compared the characteristics of 1170 patients referred for CBP surgery using multivariate logistic regression and propensity score-based analysis. Performances of the candidate urinary biomarkers at <4h post-surgery, urinary neutrophil gelatinase-associated lipocalin (uNGAL), [IGFBP7]·[TIMP-2] product (NephroCheck) and a recently developed AKI signature of 204 urinary peptides (AKI204) to predict AKI were compared in both sexes. Incidence (∼25%) and severity of AKI were similar in men and women, even after adjustment for the usual risk factors of AKI, including baseline estimated glomerular filtration rate, age, diabetes mellitus, length of CBP and red blood cell transfusion. However, at the molecular level, performances of uNGAL, NephroCheck and AKI204 to predict AKI strongly diverged between men and women. In the full cohort, as well as in subgroups of men and women, the multimarker AKI204 signature outperformed uNGAL and NephroCheck and predicted the development of AKI significantly better in women than in men. Analysis of AKI204 at the single-peptide level suggested divergences of AKI mechanisms between sexes due to increased kidney inflammation in women (increased abundance of urinary fragments of osteopontin and uromodulin). In patients referred for CBP surgery, significant clinical and biological differences between men and women as well as sexual dimorphism of AKI biomarker performances were identified. The urinary peptide signature points to sex-related molecular mechanisms underlying AKI.

Peptidome Profiling of Bubalus bubalis Urine and Assessment of Its Antimicrobial Activity against Mastitis-Causing Pathogens.

Urinary proteins have been studied quite exhaustively in the past, however, the small sized peptides have remained neglected for a long time in dairy cattle. These peptides are the products of systemic protein turnover, which are excreted out of the body and hence can serve as an important biomarker for various pathophysiologies. These peptides in other species of bovine have been reported to possess several bioactive properties. To investigate the urinary peptides in buffalo and simultaneously their bioactivities, we generated a peptidome profile from the urine of Murrah Buffaloes (n = 10). Urine samples were processed using <10 kDa MWCO filter and filtrate obtained was used for peptide extraction using Solid Phase Extraction (SPE). The nLC-MS/MS of the aqueous phase from ten animals resulted in the identification of 8165 peptides originating from 6041 parent proteins. We further analyzed these peptide sequences to identify bioactive peptides and classify them into anti-cancerous, anti-hypertensive, anti-microbial, and anti-inflammatory groups with a special emphasis on antimicrobial properties. With this in mind, we simultaneously conducted experiments to evaluate the antimicrobial properties of urinary aqueous extract on three pathogenic bacterial strains: S. aureus, E. coli, and S. agalactiae. The urinary peptides observed in the study are the result of the activity of possibly 76 proteases. The GO of these proteases showed the significant enrichment of the antibacterial peptide production. The total urinary peptide showed antimicrobial activity against the aforementioned pathogenic bacterial strains with no significant inhibitory effects against a buffalo mammary epithelial cell line. Just like our previous study in cows, the present study suggests the prime role of the antimicrobial peptides in the maintenance of the sterility of the urinary tract in buffalo by virtue of their amino acid composition.

Preparation and Immunochemical Characterization of a Water-Soluble Gluten Peptide Fraction for Improving the Diagnosis of Celiac Disease.

The diagnosis of celiac disease (CD) is complex and requires a multi-step procedure (symptoms, serology, duodenal biopsy, effect of a gluten-free diet, and optional genetic). The aim of the study was to contribute to the improvement of CD diagnosis by preparing a water-soluble gluten peptide fraction (called Solgluten) and by selecting gluten-specific enzyme-linked immunosorbent assays (ELISA) for the detection of gluten immunogenic gluten peptides (GIPs) in urine and blood serum spiked with Solgluten. Food-grade Solgluten was prepared by the extraction of a peptic digest of vital gluten with water, centrifugation, and freeze-drying. The process was relatively easy, repeatable, and cheap. The content of gliadin-derived GIPs was 491 mg/g. Solgluten was used as antigenic material to compare two competitive ELISA kits (R7021 and K3012) and two sandwich ELISA kits (M2114 and R7041) in their quality regarding the quantitation of GIPs in urine and blood serum. The quality parameters were the reactivity, sensitivity, coefficients of variation and determination, and curve shape. The evaluation of the kits showed a number of discrepancies in individual quality parameters measured in urine and serum. Due to the lowest limit of quantitation and the highest coefficient of determination, M2114 may be the first choice, while R7021 appeared to be less suitable because of the high coefficients of variation and unfavorable curve progression. The results set the stage for improving CD diagnosis by supplementing conventional blood tests with oral provocation with Solgluten and subsequent ELISA measurement of GIPs that could support the no-biopsy approach and by better assessing the effect of a gluten-free diet by monitoring adherence to the diet by measuring GIPs in urine and blood.