Protease profiling of different biofluids in type 1 diabetes mellitus

Assessing Sarcocornia as a Salt Substitute: Effects on Lipid Profile and Gelatinase Activity

Sodium, although essential for life, is a key factor in changes in vascular function and cardiovascular disease when consumed in excess. Sarcocornia spp., a halophyte plant with many nutritional benefits, presents itself as a promising substitute for the consumption of purified salt. Matrix metalloproteinases (MMPs) 2 and 9 are widely studied due to their action in physiological processes and as biomarkers at the diagnostic level due to their increased expression in inflammatory processes. This study aimed to evaluate whether replacing salt with Sarcocornia perennis (S. perennis) powder in healthy young people leads to an improvement in biochemical profiles and the attenuation of MMP-2 and MMP-9 activity. In the present study, 30 participants were randomized into a control group that consumed salt and an intervention group that replaced salt with powdered S. perennis. The evaluation of the biochemical parameters was carried out by the spectrophotometry method, and the evaluation of MMP activity was carried out by zymography. A significant decrease was observed in the intervention group in total cholesterol, high-density lipoprotein cholesterol (HDL-c), and creatinine (p-value ≤ 0.05), along with lower but not significantly different mean values of triglycerides. Regarding MMP activity after the intervention, a lower mean value was observed for MMP-9 activity, with there being higher mean values for MMP-2 activity, both with p-values ≥ 0.05. The results confirmed that the consumption of S. perennis is a beneficial choice for health regarding the lipid profile. The evaluation of MMP activity indicated the potential of S. perennis in the regulation of MMP-9 activity in healthy individuals, along with the need for the further study of these proteases in individuals with pathologies.

Laboratory Assessment of the Effects of AGA@4life Multidisciplinary Intervention on the Inflammatory Profile, MMPs, and TIMPs in a Geriatric Population

In recent years, the world's aging population has increased, contributing to the development of age-related pathologies, which have been aggravated by physical inactivity and excessive fat intake. This study aimed to evaluate the effect of implementing a nutritional program (control group-CG) combined with exercise (intervention group-IG) on the inflammatory profile, MMPs, and TIMPs in a group of 34 elderly participants (IG, n = 18; CG, n = 16). Participants underwent a full multidisciplinary diagnostic evaluation (T0), with the gathering of clinical information and biochemical and hematological determinations being re-evaluated eight weeks later (T1). A diet manual was made, which provided a selection of different types of diets resulting from the nutritional needs of the different users at the center. The aerobic exercise consisted of two sessions per week with a total duration of 1 h. The laboratory evaluation was performed by slot blot. Statistical analysis included a paired sample t-test and Spearman's correlation coefficient. We observed that in the IG, there was a significant increase at T1 of TNF-α (p < 0.05) and MMP-2 (p < 0.05), without changes in IL-6 and MMP-9, showing that the intervention did not cause an exacerbated inflammatory response in exercised elderly people. The intervention program implemented showed potential to contribute to better active aging strategies, taking advantage of the known benefits of exercise without inducing a harmful inflammatory response in elderly participants.

Heparin-binding protein as a predictor of mortality in patients with diabetes mellitus and community-acquired pneumonia in intensive care unit : a propensity score matched study

BACKGROUND

Patients with diabetes mellitus (DM) are vulnerable to community-acquired pneumonia (CAP), which have a high mortality rate. We aimed to investigate the value of heparin-binding protein (HBP) as a prognostic marker of mortality in patients with DM and CAP.

METHODS

This retrospective study included CAP patients who were tested for HBP at intensive care unit (ICU) admission from January 2019 to April 2020. Patients were allocated to the DM or non-DM group and paired with propensity score matching. Baseline characteristics and clinical outcomes up to 90 days were evaluated. The primary outcome was the 10-day mortality. Receiver operating characteristic (ROC) curves, Kaplan-Meier analysis, and Cox regression were used for statistical analysis.

RESULTS

Among 152 enrolled patients, 60 pairs were successfully matched. There was no significant difference in 10-day mortality, while more patients in the DM group died within 28 d (P=0.024) and 90 d (P=0.008). In the DM group, HBP levels at ICU admission were higher in 10-day non-survivors than in 10-day survivors (median 182.21 [IQR: 55.43-300] ng/ml vs. median 66.40 [IQR: 34.13-107.85] ng/mL, P=0.019), and HBP levels could predict the 10-day mortality with an area under the ROC curve of 0.747. The cut-off value, sensitivity, and specificity were 160.6 ng/mL, 66.7%, and 90.2%, respectively. Multivariate Cox regression analysis indicated that HBP was an independent prognostic factor for 10-day (HR 7.196, 95%CI: 1.596-32.455, P=0.01), 28-day (HR 4.381, 95%CI: 1.449-13.245, P=0.009), and 90-day mortality (HR 4.581, 95%CI: 1.637-12.819, P=0.004) in patients with DM.

CONCLUSION

Plasma HBP at ICU admission was associated with the 10-day, 28-day, and 90-day mortality, and might be a prognostic factor in patients with DM and CAP.

Molecular Pathways of Diabetic Kidney Disease Inferred from Proteomics

Diabetic kidney disease (DKD) affects an estimated 20-40% of type 2 diabetes patients and is among the most prevalent microvascular complications in this patient population, contributing to high morbidity and mortality rates. Currently, changes in albuminuria status are thought to be a primary indicator of the onset or progression of DKD, yet progressive nephropathy and renal impairment can occur in certain diabetic individuals who exhibit normal urinary albumin levels, emphasizing the lack of sensitivity and specificity associated with the use of albuminuria as a biomarker for detecting diabetic kidney disease and predicting DKD risk. According to the study, a non-invasive method for early detection or prediction of DKD may involve combining proteomic analytical techniques such second generation sequencing, mass spectrometry, two-dimensional gel electrophoresis, and other advanced system biology algorithms. Another category of proteins of relevance may now be provided by renal tissue biomarkers. The establishment of reliable proteomic biomarkers of DKD represents a novel approach to improving the diagnosis, prognostic evaluation, and treatment of affected patients. In the present review, a series of protein biomarkers that have been characterized to date are discussed, offering a theoretical foundation for future efforts to aid patients suffering from this debilitating microvascular complication.

Tracking Prostate Carcinogenesis over Time through Urine Proteome Profiling in an Animal Model: An Exploratory Approach

Prostate cancer (PCa) is one of the most lethal diseases in men, which justifies the search for new diagnostic tools. The aim of the present study was to gain new insights into the progression of prostate carcinogenesis by analyzing the urine proteome. To this end, urine from healthy animals and animals with prostate adenocarcinoma was analyzed at two time points: 27 and 54 weeks. After 54 weeks, the incidence of pre-neoplastic and neoplastic lesions in the PCa animals was 100%. GeLC-MS/MS and subsequent bioinformatics analyses revealed several proteins involved in prostate carcinogenesis. Increased levels of retinol-binding protein 4 and decreased levels of cadherin-2 appear to be characteristic of early stages of the disease, whereas increased levels of enolase-1 and T-kininogen 2 and decreased levels of isocitrate dehydrogenase 2 describe more advanced stages. With increasing age, urinary levels of clusterin and corticosteroid-binding globulin increased and neprilysin levels decreased, all of which appear to play a role in prostate hyperplasia or carcinogenesis. The present exploratory analysis can be considered as a starting point for studies targeting specific human urine proteins for early detection of age-related maladaptive changes in the prostate that may lead to cancer.

Cathepsin C is a novel mediator of podocyte and renal injury induced by hyperglycemia

A growing body of evidence suggests a role of proteolytic enzymes in the development of diabetic nephropathy. Cathepsin C (CatC) is a well-known regulator of inflammatory responses, but its involvement in podocyte and renal injury remains obscure. We used Zucker rats, a genetic model of metabolic syndrome and insulin resistance, to determine the presence, quantity, and activity of CatC in the urine. In addition to the animal study, we used two cellular models, immortalized human podocytes and primary rat podocytes, to determine mRNA and protein expression levels via RT-PCR, Western blot, and confocal microscopy, and to evaluate CatC activity. The role of CatC was analyzed in CatC-depleted podocytes using siRNA and glycolytic flux parameters were obtained from extracellular acidification rate (ECAR) measurements. In functional analyses, podocyte and glomerular permeability to albumin was determined. We found that podocytes express and secrete CatC, and a hyperglycemic environment increases CatC levels and activity. Both high glucose and non-specific activator of CatC phorbol 12-myristate 13-acetate (PMA) diminished nephrin, cofilin, and GLUT4 levels and induced cytoskeletal rearrangements, increasing albumin permeability in podocytes. These negative effects were completely reversed in CatC-depleted podocytes. Moreover, PMA, but not high glucose, increased glycolytic flux in podocytes. Finally, we demonstrated that CatC expression and activity are increased in the urine of diabetic Zucker rats. We propose a novel mechanism of podocyte injury in diabetes, providing deeper insight into the role of CatC in podocyte biology.

Proteomic Biomarkers of Retinal Inflammation in Diabetic Retinopathy

Diabetic retinopathy (DR), a sight-threatening neurovasculopathy, is the leading cause of irreversible blindness in the developed world. DR arises as the result of prolonged hyperglycemia and is characterized by leaky retinal vasculature, retinal ischemia, retinal inflammation, angiogenesis, and neovascularization. The number of DR patients is growing with an increase in the elderly population, and therapeutic approaches are limited, therefore, new therapies to prevent retinal injury and enhance repair are a critical unmet need. Besides vascular endothelial growth factor (VEGF)-induced vascular proliferation, several other mechanisms are important in the pathogenesis of diabetic retinopathy, including vascular inflammation. Thus, combining anti-VEGF therapy with other new therapies targeting these pathophysiological pathways of DR may further optimize treatment outcomes. Technological advancements have allowed for high-throughput proteomic studies examining biofluids such as aqueous humor, vitreous humor, tear, and serum. Many DR biomarkers have been identified, especially proteins involved in retinal inflammatory processes. This review attempts to summarize the proteomic biomarkers of DR-associated retinal inflammation identified over the last several years.

Proteomic and metabolomic approaches in the search for biomarkers in chronic kidney disease

Chronic kidney disease (CKD) is an aging-related disorder that represents a major global public health burden. Current biochemical biomarkers, such as serum creatinine and urinary albumin, have important limitations when used to identify the earliest indication of CKD or in tracking the progression to more advanced CKD. These issues underline the importance of finding and testing new molecular biomarkers that are capable of successfully meeting this clinical need. The measurement of changes in nature and/or levels of proteins and metabolites in biological samples from patients provide insights into pathophysiological processes. Proteomic and metabolomic techniques provide opportunities to record dynamic chemical signatures in patients over time. This review article presents an overview of the recent developments in the fields of metabolomics and proteomics in relation to CKD. Among the many different proteomic biomarkers proposed, there is particular interest in the CKD273 classifier, a urinary proteome biomarker reported to predict CKD progression and with implementation potential. Other individual non-invasive peptidomic biomarkers that are potentially relevant for CKD detection include type 1 collagen, uromodulin and mucin-1. Despite the limited sample sizes and variability of the metabolomics studies, some metabolites such as trimethylamine N-oxide, kynurenine and citrulline stand out as potential biomarkers in CKD.

MALDI-TOF peptidomic analysis of serum and post-prostatic massage urine specimens to identify prostate cancer biomarkers

Background

Lower urinary tract symptoms (LUTS) and prostate specific antigen-based parameters seem to have only a limited utility for the differential diagnosis of prostate cancer (PCa). MALDI-TOF/MS peptidomic profiling could be a useful diagnostic tool for biomarker discovery, although reproducibility issues have limited its applicability until now. The current study aimed to evaluate a new MALDI-TOF/MS candidate biomarker.

Methods

Within- and between-subject variability of MALDI-TOF/MS-based peptidomic urine and serum analyses were evaluated in 20 and 15 healthy donors, respectively. Normalizations and approaches for accounting below limit of detection (LOD) values were utilized to enhance reproducibility, while Monte Carlo experiments were performed to verify whether measurement error can be dealt with LOD data. Post-prostatic massage urine and serum samples from 148 LUTS patients were analysed using MALDI-TOF/MS. Regression-calibration and simulation and extrapolation methods were used to derive the unbiased association between peptidomic features and PCa.

Results

Although the median normalized peptidomic variability was 24.9%, the within- and between-subject variability showed that median normalization, LOD adjustment, and log₂ data transformation were the best combination in terms of reliability; in measurement error conditions, intraclass correlation coefficient was a reliable estimate when the LOD/2 was substituted for below LOD values. In the patients studied, 43 peptides were shared by the urine and serum, and several features were found to be associated with PCa. Only few serum features, however, show statistical significance after the multiple testing procedures were completed. Two serum fragmentation patterns corresponded to the complement C4-A.

Conclusions

MALDI-TOF/MS serum peptidome profiling was more efficacious with respect to post-prostatic massage urine analysis in discriminating PCa.

Electronic supplementary material

The online version of this article (10.1186/s12014-018-9199-8) contains supplementary material, which is available to authorized users.

Anti-apoptotic activity of human matrix metalloproteinase-2 attenuates diabetes mellitus

BACKGROUND

Chronic progression of diabetes is associated with decreased pancreatic islet mass due to apoptosis of β-cells. Patients with diabetes have increased circulating matrix metalloproteinase-2 (MMP2); however, the physiological significance has remained elusive. This study tested the hypothesis that MMP2 inhibits cell apoptosis, including islet β-cells.

METHODS

Samples from diabetic patients and newly developed transgenic mice overexpressing human MMP2 (hMMP2) were harnessed, and diabetes was induced with streptozotocin.

RESULTS

Circulating hMMP2 was significantly increased in diabetic patients compared to controls and significantly correlated with the serum C-peptide levels. The diabetic hMMP2 transgenic mice showed significant improvements in glycemia, glucose tolerance and insulin secretion compared to diabetic wild type mice. Importantly, the increased hMMP2 levels in mice correlated with significant reduction in islet β-cell apoptosis compared to wild-type counterparts, and an inhibitor of hMMP2 reversed this mitigating activity against diabetes. The increased activation of Akt and BAD induced by hMMP2 in β-cells compared to controls, links this signaling pathway to the anti-apoptotic activity of hMMP2, a property that was reversible by both an hMMP2 inhibitor and antibody against integrin-β3.

CONCLUSION

Overall, this study demonstrates that increased expression of hMMP2 may attenuate the severity of diabetes by protecting islet β-cells from apoptosis through an integrin-mediated activation of the Akt/BAD pathway.

Urinary Proteomics for Diagnosis and Monitoring of Diabetic Nephropathy

The last decade has seen a surge in publications describing novel biomarkers for early detection of diabetic nephropathy (DN), but as yet none have outperformed albuminuria in well-designed prospective studies. This is partially attributable to our incomplete understanding of the many complex interrelated mechanisms underlying DN development, a heterogeneous process unlikely to be captured by a single biomarker. Proteomics offers the advantage of simultaneously analysing the entire protein content of a biological sample, and the technique has gained attention as a potential tool for a more accurate diagnosis of disease at an earlier stage as well as a means by which to unravel the pathogenesis of complex diseases such as DN using an untargeted approach. This review will discuss the potential of proteomics as both a clinical and research tool, evaluating exploratory work in animal models as well as diagnostic potential in human subjects.

An analysis of the impact of pre-analytical factors on the urine proteome: Sample processing time, temperature, and proteolysis

Purpose

We have examined the impact of sample processing time delay, temperature, and the addition of protease inhibitors (PIs) on the urinary proteome and peptidome, an important aspect of biomarker studies.

Experimental design

Ten urine samples from patients with varying pathologies were each divided and PIs added to one‐half, with aliquots of each then processed and frozen immediately, or after a delay of 6 h at 4°C or room temperature (20–22°C), effectively yielding 60 samples in total. Samples were then analyzed by 2D‐PAGE, SELDI‐TOF‐MS, and immunoassay.

Results

Interindividual variability in profiles was the dominant feature in all analyses. Minimal changes were observed by 2D‐PAGE as a result of delay in processing, temperature, or PIs and no changes were seen in IgG, albumin, β₂‐microglobulin, or α₁‐microglobulin measured by immunoassay. Analysis of peptides showed clustering of some samples by presence/absence of PIs but the extent was very patient‐dependent with most samples showing minimal effects.

Conclusions and clinical relevance

The extent of processing‐induced changes and the benefit of PI addition are patient‐ and sample‐dependent. A consistent processing methodology is essential within a study to avoid any confounding of the results.

Biofluid proteases profiling in diabetes mellitus

The investigation of protease relevance in biologic systems beyond catabolism of proteins and peptides to amino acids has stimulated interest as to their role in the pathogenesis of several disorders including diabetes mellitus (DM). Evaluation of proteases and the assessment of their activity in biofluids are fundamental to elucidate these proteolytic systems in DM and its related complications. In contrast to traditional immunoassay or substrate based approaches that targeted specific proteases and their inhibitors, the field of degradomics has provided a comprehensive approach to study these enzymes. Although the degradome contains over 500 proteases, very few have been associated with DM and its micro- and macrovascular complications. In this paper, we review these proteases and their respective inhibitors with emphasis on DM. It is likely that future research will expand these initial studies and look to develop high throughput automated technologies to identify and characterize biofluid proteases of diagnostic and prognostic value in other pathologies.

Magnetic chelating nanoprobes for enrichment and selective recovery of metalloproteases from human saliva

Magnetic nanoparticles effective in the selective recovery of metalloproteases from human saliva were fabricated by surface modification of Fe₃O₄@SiO₂nanoparticles with EDTA-TMS.

Comparative proteomic analyses of urine from rat urothelial carcinoma chemically induced by exposure to N-butyl-N-(4-hydroxybutyl)-nitrosamine

Bladder cancer is estimated to be the ninth most common malignancy with a high rate of recurrence and progression despite therapy, early diagnosis being crucial for timely intervention.