Discovery and Validation of a Urinary Exosome mRNA Signature for the Diagnosis of Human Kidney Transplant Rejection.

BACKGROUND: Developing a noninvasive clinical test to accurately diagnose kidney allograft rejection is critical to improve allograft outcomes. Urinary exosomes, tiny vesicles released into the urine that carry parent cells' proteins and nucleic acids, reflect the biologic function of the parent cells within the kidney, including immune cells. Their stability in urine makes them a potentially powerful tool for liquid biopsy and a noninvasive diagnostic biomarker for kidney-transplant rejection. METHODS: Using 192 of 220 urine samples with matched biopsy samples from 175 patients who underwent a clinically indicated kidney-transplant biopsy, we isolated urinary exosomal mRNAs and developed rejection signatures on the basis of differential gene expression. We used crossvalidation to assess the performance of the signatures on multiple data subsets. RESULTS: An exosomal mRNA signature discriminated between biopsy samples from patients with all-cause rejection and those with no rejection, yielding an area under the curve (AUC) of 0.93 (95% CI, 0.87 to 0.98), which is significantly better than the current standard of care (increase in eGFR AUC of 0.57; 95% CI, 0.49 to 0.65). The exosome-based signature's negative predictive value was 93.3% and its positive predictive value was 86.2%. Using the same approach, we identified an additional gene signature that discriminated patients with T cell-mediated rejection from those with antibody-mediated rejection (with an AUC of 0.87; 95% CI, 0.76 to 0.97). This signature's negative predictive value was 90.6% and its positive predictive value was 77.8%. CONCLUSIONS: Our findings show that mRNA signatures derived from urinary exosomes represent a powerful and noninvasive tool to screen for kidney allograft rejection. This finding has the potential to assist clinicians in therapeutic decision making.

Effectiveness of Helicobacter pylori eradication in preventing metachronous gastric cancer and preneoplastic lesions. A systematic review and meta-analysis.

BACKGROUND: Helicobacter pylori is a significant risk factor for gastric cancer. Recent trials show eradication decreases the incidence of gastric cancer in patients with early-stage gastric cancer. However, data on gastric cancer prevention are inconsistent for patients with precancerous lesions such as atrophic gastritis and intestinal metaplasia. AIM: The aim of the study is to assess the efficacy of H. pylori eradication in gastric cancer prevention in patients with varying risk factors for gastric cancer at baseline. METHODS: A systematic review and meta-analysis were performed according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. PubMed, Medline, and Google Scholar were searched from inception through March 2019 for randomized controlled trials (RCTs) studying H. pylori eradication on gastric cancer prevention. We estimated the odds ratio (OR) with 95% confidence interval (CI) for each outcome using a random-effects model. P values of less than 0.05 were considered significant. RESULTS: Nine RCTs with total of 6967 patient were included in the analysis. There was significant reduction in gastric cancer incidence in the H. pylori group for patients with early gastric cancer status post endoscopic mucosal resection OR, 0.47; 95% CI, 0.33-0.67; P < 0.0001; I = 0%. There was no difference in gastric cancer incidence in patients with atrophic gastritis and intestinal metaplasia at baseline for H. pylori arm OR, 0.67; 95% CI, 0.42-1.07; P = 0.09; I = 0%). Atrophic gastritis and intestinal metaplasia improved from baseline in the H. pylori arm compared to placebo OR, 2.61; 95% CI, 1.41-4.81; P = 0.002; I = 88 and OR, 2.61; 95% CI, 1.66-4.11; P ≤ 0.0001; I = 0%, respectively. CONCLUSIONS: H. pylori eradication is associated with reduced gastric cancer incidence in patients with early-stage gastric cancer and improvement in atrophic gastritis and intestinal metaplasia. There was no difference in gastric cancer incidence in patients with atrophic gastritis and intestinal metaplasia at baseline.

The promising role of probiotic and synbiotic therapy in aminotransferase levels and inflammatory markers in patients with nonalcoholic fatty liver disease - a systematic review and meta-analysis.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease worldwide. The pathogenesis of NAFLD is complex and multifactorial. There is growing evidence that altered gut microbiota plays a key role in NAFLD progression. Probiotics/synbiotics, by modifying gut microbiota, may be a promising treatment choice for NAFLD management. AIM: The aim of this study was to study the effect of probiotics/synbiotics on various laboratory and radiographic parameters in NAFLD management. MATERIALS AND METHODS: A systematic review and meta-analysis were carried out according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. We searched PubMed, Medline, and Google Scholar for randomized-controlled trials that studied the role of probiotics/synbiotics in NAFLD. The primary outcome was change in baseline alanine aminotransferase and aspartate aminotransferase in the treatment arm. We used a random-effects model and inverse variance for the continuous data to estimate the mean difference (MD) and the standard mean difference (SMD) in RevMan Version 5.3. RESULTS: We included 12 randomized-controlled trials for analysis. The intervention arm, which comprised of the probiotic and/or the synbiotic arm, showed a significant improvement in alanine aminotransferase levels, MD=-13.93, confidence interval (CI)=-20.20 to -7.66, P value of less than 0.0001, I=92% and aspartate aminotransferase levels MD=-11.45, CI=-15.15 to -7.74, P value of less than 0.00001, I=91%. There was a reduction in high-sensitivity C-reactive protein levels in the intervention arm, SMD=-0.68, CI=-1.10 to -0.26, P value of 0.001, I=0%. The liver fibrosis score improved in the intervention arm, MD=-0.71, CI=-0.81 to -0.61, P value less than 0.00001, I=0%. CONCLUSION: Probiotic/synbiotic use improves aminotransaminase levels and reduces proinflammatory marker high-sensitivity C-reactive protein and liver fibrosis in NAFLD patients.

Human regulatory T cells undergo self-inflicted damage via granzyme pathways upon activation.

Tregs hold great promise as a cellular therapy for multiple immunologically mediated diseases, given their ability to control immune responses. The success of such strategies depends on the expansion of healthy, suppressive Tregs ex vivo and in vivo following the transfer. In clinical studies, levels of transferred Tregs decline sharply in the blood within a few days of the transfer. Tregs have a high rate of apoptosis. Here, we describe a new mechanism of Treg self-inflicted damage. We show that granzymes A and -B (GrA and GrB), which are highly upregulated in human Tregs upon stimulation, leak out of cytotoxic granules to induce cleavage of cytoplasmic and nuclear substrates, precipitating apoptosis in target cells. GrA and GrB substrates were protected from cleavage by inhibiting granzyme activity in vitro. Additionally, we show - by using cytometry by time of flight (CYTOF) - an increase in GrB-expressing Tregs in the peripheral blood and renal allografts of transplant recipients undergoing rejection. These GrB-expressing Tregs showed an activated phenotype but were significantly more apoptotic than non-GrB expressing Tregs. This potentially novel finding improves our understanding of Treg survival and suggests that manipulating Gr expression or activity might be useful for designing more effective Treg therapies.

Brief treatment with a highly selective immunoproteasome inhibitor promotes long-term cardiac allograft acceptance in mice.

Constitutive proteasomes (c-20S) are ubiquitously expressed cellular proteases that degrade polyubiquitinated proteins and regulate cell functions. An isoform of proteasome, the immunoproteasome (i-20S), is highly expressed in human T cells, dendritic cells (DCs), and B cells, suggesting that it could be a potential target for inflammatory diseases, including those involving autoimmunity and alloimmunity. Here, we describe DPLG3, a rationally designed, noncovalent inhibitor of the immunoproteasome chymotryptic subunit ß5i that has thousands-fold selectivity over constitutive ß5c. DPLG3 suppressed cytokine release from blood mononuclear cells and the activation of DCs and T cells, diminished accumulation of effector T cells, promoted expression of exhaustion and coinhibitory markers on T cells, and synergized with CTLA4-Ig to promote long-term acceptance of cardiac allografts across a major histocompatibility barrier. These findings demonstrate the potential value of using brief posttransplant immunoproteasome inhibition to entrain a long-term response favorable to allograft survival as part of an immunomodulatory regimen that is neither broadly immunosuppressive nor toxic.