Development of a Diagnostic Model for Pancreatic Ductal Adenocarcinoma Using Machine Learning and Blood-Based miRNAs.

INTRODUCTION: Pancreatic ductal adenocarcinoma (PDAC) has the lowest survival rate among all major cancers due to a lack of symptoms in early stages, early detection tools, and optimal therapies for late-stage patients. Thus, effective and non-invasive diagnostic tests are greatly needed. Recently, circulating miRNAs have been reported to be altered in PDAC. They are promising biomarkers because of stability in the blood, ease of non-invasive detection, and convenient screening methods. This study aimed to use blood-based miRNA biomarkers and various analysis methods in the development of a machine-learning (ML) model for PDAC. METHODS: Blood-based miRNAs associated with PDAC were collected from open sources. miRNA sequences, targeted genes, and involved pathways were used to construct a set of descriptors for an ML model. RESULTS: Bioinformatics analysis revealed that most genes in pancreatic cancer and insulin signaling pathways were targeted by the PDAC-related miRNAs. The best-performing ML model with the Random Forest classifier was able to achieve an accuracy of 88.4%. Model evaluations of an independent PDAC-associated miRNAs test set had 100% accuracy while non-cancer miRNAs had 52.4% accuracy, indicating specificity to PDAC. CONCLUSIONS: Our results suggest an ML model developed using blood-based miRNA biomarkers' target gene, pathway, and sequence features could be potentially implicated in PDAC diagnostics.

Smoking-related dysregulation of plasma circulating microRNAs: the Rotterdam study.

BACKGROUND: MicroRNAs (miRNAs) are post-transcriptional regulators of gene expression. Differential miRNA expression, which is widely shown to be associated with the pathogenesis of various diseases, can be influenced by lifestyle factors, including smoking. This study aimed to investigate the plasma miRNA signature of smoking habits, the potential effect of smoking cessation on miRNA levels, and relate the findings with lung cancer incidence. RESULTS: A targeted RNA-sequencing approach measured plasma miRNA levels in 2686 participants from the population-based Rotterdam study cohort. The association between cigarette smoking (current versus never) and 591 well-expressed miRNAs was assessed via adjusted linear regression models, identifying 41 smoking-associated miRNAs that passed the Bonferroni-corrected threshold (P < 0.05/591 = 8.46 × 10-5). Moreover, we found 42 miRNAs with a significant association (P < 8.46 × 10-5) between current (reference group) and former smokers. Then, we used adjusted linear regression models to explore the effect of smoking cessation time on miRNA expression levels. The expression levels of two miRNAs were significantly different within 5 years of cessation (P < 0.05/41 = 1.22 × 10-3) from current smokers, while for cessation time between 5 and 15 years we found 19 miRNAs to be significantly different from current smokers, and finally, 38 miRNAs were significantly different after more than 15 years of cessation time (P < 1.22 × 10-3). These results imply the reversibility of the smoking effect on plasma levels of at least 38 out of the 41 smoking-miRNAs following smoking cessation. Next, we found 8 out of the 41 smoking-related miRNAs to be nominally associated (P < 0.05) with the incidence of lung cancer. CONCLUSIONS: This study demonstrates smoking-related dysregulation of plasma miRNAs, which might have a potential for reversibility when comparing different smoking cessation groups. The identified miRNAs are involved in several cancer-related pathways and include 8 miRNAs associated with lung cancer incidence. Our results may lay the groundwork for further investigation of miRNAs as potential mechanism linking smoking, gene expression and cancer.

Diagnosis of Cutaneous Acute Graft­Versus­Host Disease Through Circulating Plasma miR-638, miR-6511b-5p, miR-3613-5p, miR-455-3p, miR-5787, and miR-548a-3p as Prospective Noninvasive Biomarkers Following Allogeneic Hematopoietic Stem Cell Transplantation.

BACKGROUND: There are currently no laboratory tests that can accurately predict the likelihood of developing acute graft-versus-host disease (aGVHD), a patient's response to treatment, or their survival chance. This research aimed to establish circulating miRNAs as diagnostic, prognostic, or predictive biomarkers of aGVHD. METHODS: In a prospective cohort, we studied the incidence of cutaneous aGVHD in AML patients undergoing allo-HSCT at Shariati Hospital in Tehran, Iran during 2020-2023. Patients with cutaneous aGVHD were labeled as the case group, while patients without cutaneous aGVHD were selected as the control group. Accordingly, the expression levels of six significant miRNAs (miR-638, miR-6511b-5p, miR-3613-5p, miR-455-3p, miR-5787, miR-548a-3p) were evaluated by quantitative reverse transcription-polymerase chain reaction (RTqPCR) in three different time-points: before transplantation, on day 14 and day 21 after transplantation. RESULTS: The levels of plasma miR-455-3p, miR-5787, miR-638, and miR-3613-5p were significantly downregulated, while miR-548a-3p, and miR-6511b-5p were significantly upregulated in individuals with cutaneous aGVHD in comparison to patients without GVHD. Additionally, the possibility for great diagnostic accuracy for cutaneous aGVHD was revealed by ROC curve analysis of differentially expressed miRNAs (DEMs). CONCLUSION: The study findings encourage us to hypothesize that the aforementioned miRNAs may contribute to the predominance of aGVHD, particularly low-grade cutaneous aGVHD.

The potential of circulating microRNAs as novel diagnostic biomarkers of COVID-19: a systematic review and meta-analysis.

INTRODUCTION: The COVID-19 pandemic has caused an unprecedented health threat globally, necessitating innovative and efficient diagnostic approaches for timely identification of infected individuals. Despite few emerging reports, the clinical utility of circulating microRNAs (miRNAs) in early and accurate diagnosis of COVID-19 is not well-evidenced. Hence, this meta-analysis aimed to explore the diagnostic potential of circulating miRNAs for COVID-19. The protocol for this study was officially recorded on PROSPERO under registration number CRD42023494959. METHODS: Electronic databases including Embase, PubMed, Scopus, and other sources were exhaustively searched to recover studies published until 16th January, 2024. Pooled specificity, sensitivity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic ratio (DOR), positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) were computed from the metadata using Stata 14.0 software. Risk of bias appraisal of included articles was carried out using Review Manager (Rev-Man) 5.3 package through the modified QUADAS-2 tool. Subgroup, heterogeneity, meta-regression and sensitivity analyses were undertaken. Publication bias and clinical applicability were also evaluated via Deeks' funnel plot and Fagan nomogram (scattergram), respectively. RESULT: A total of 43 studies from 13 eligible articles, involving 5175 participants (3281 COVID-19 patients and 1894 healthy controls), were analyzed. Our results depicted that miRNAs exhibit enhanced pooled specificity 0.91 (95% CI: 0.88-0.94), sensitivity 0.94 (95% CI: 0.91-0.96), DOR of 159 (95% CI: 87-288), and AUC values of 0.97 (95% CI: 0.95-0.98) with high pooled PPV 96% (95% CI: 94-97%) and NPV 88% (95% CI: 86-90%) values. Additionally, highest diagnostic capacity was observed in studies involving larger sample size (greater than 100) and those involving the African population, demonstrating consistent diagnostic effectiveness across various specimen types. Notably, a total of 12 distinct miRNAs were identified as suitable for both exclusion and confirmation of COVID-19 cases, denoting their potential clinical applicability. CONCLUSION: Our study depicted that miRNAs show significantly high diagnostic accuracy in differentiating COVID-19 patients from healthy counterparts, suggesting their possible use as viable biomarkers. Nonetheless, thorough and wide-ranging longitudinal researches are necessary to confirm the clinical applicability of miRNAs in diagnosing COVID-19.

The Circulating Biomarkers League: Combining miRNAs with Cell-Free DNAs and Proteins.

The potential of liquid biopsy for the prognosis and diagnosis of diseases is unquestionable. Within the evolving landscape of disease diagnostics and personalized medicine, circulating microRNAs (c-miRNAs) stand out among the biomarkers found in blood circulation and other biological fluids due to their stability, specificity, and non-invasive detection in biofluids. However, the complexity of human diseases and the limitations inherent in single-marker diagnostics highlight the need for a more integrative approach. It has been recently suggested that a multi-analyte approach offers advantages over the single-analyte approach in the prognosis and diagnosis of diseases. In this review, we explore the potential of combining three well-studied classes of biomarkers found in blood circulation and other biofluids-miRNAs, DNAs, and proteins-to enhance the accuracy and efficacy of disease detection and monitoring. Initially, we provide an overview of each biomarker class and discuss their main advantages and disadvantages highlighting the superiority of c-miRNAs over the other classes of biomarkers. Additionally, we discuss the challenges and future directions in integrating these biomarkers into clinical practice, emphasizing the need for standardized protocols and further validation studies. This integrated approach has the potential to revolutionize precision medicine by offering insights into disease mechanisms, facilitating early detection, and guiding personalized therapeutic strategies. The collaborative power of c-miRNAs with other biomarkers represents a promising frontier in the comprehensive understanding and management of complex diseases. Nevertheless, several challenges must be addressed before this approach can be translated into clinical practice.

Modulation of miR-29a and miR-29b Expression and Their Target Genes Related to Inflammation and Renal Fibrosis by an Oral Nutritional Supplement with Probiotics in Malnourished Hemodialysis Patients.

Malnutrition is prevalent in patients with chronic kidney disease (CKD), especially those on hemodialysis. Recently, our group described that a new oral nutritional supplement (ONS), specifically designed for malnourished (or at risk) hemodialysis patients with a "similar to the Mediterranean diet" pattern, improved caloric-protein intake, nutritional status and biomarkers of inflammation and oxidation. Our aim in this study was to evaluate whether the new ONS, associated with probiotics or not, may produce changes in miRNA's expression and its target genes in malnourished hemodialysis patients, compared to individualized diet recommendations. We performed a randomized, multicenter, parallel-group trial in malnourished hemodialysis patients with three groups (1: control (C) individualized diet (n = 11); 2: oral nutritional supplement (ONS) + placebo (ONS-PL) (n = 10); and 3: ONS + probiotics (ONS-PR) (n = 10)); the trial was open regarding the intake of ONS or individualized diet recommendations but double-blinded for the intake of probiotics. MiRNAs and gene expression levels were analyzed by RT-qPCR at baseline and after 3 and 6 months. We observed that the expression of miR-29a and miR-29b increased significantly in patients with ONS-PR at 3 months in comparison with baseline, stabilizing at the sixth month. Moreover, we observed differences between studied groups, where miR-29b expression levels were elevated in patients receiving ONS-PR compared to the control group in the third month. Regarding the gene expression levels, we observed a decrease in the ONS-PR group compared to the control group in the third month for RUNX2 and TNFα. TGFB1 expression was decreased in the ONS-PR group compared to baseline in the third month. PTEN gene expression was significantly elevated in the ONS-PR group at 3 months in comparison with baseline. LEPTIN expression was significantly increased in the ONS-PL group at the 3-month intervention compared to baseline. The new oral nutritional supplement associated with probiotics increases the expression levels of miR-29a and miR-29b after 3 months of intervention, modifying the expression of target genes with anti-inflammatory and anti-fibrotic actions. This study highlights the potential benefit of this oral nutritional supplement, especially associated with probiotics, in malnourished patients with chronic renal disease on hemodialysis.

Circulating microRNA miR-425-5p Associated with Brain White Matter Lesions and Inflammatory Processes.

White matter lesions (WML) emerge as a consequence of vascular injuries in the brain. While they are commonly observed in aging, associations have been established with neurodegenerative and neurological disorders such as dementia or stroke. Despite substantial research efforts, biological mechanisms are incomplete and biomarkers indicating WMLs are lacking. Utilizing data from the population-based Study of Health in Pomerania (SHIP), our objective was to identify plasma-circulating micro-RNAs (miRNAs) associated with WMLs, thus providing a foundation for a comprehensive biological model and further research. In linear regression models, direct association and moderating factors were analyzed. In 648 individuals, we identified hsa-miR-425-5p as directly associated with WMLs. In subsequent analyses, hsa-miR-425-5p was found to regulate various genes associated with WMLs with particular emphasis on the SH3PXD2A gene. Furthermore, miR-425-5p was found to be involved in immunological processes. In addition, noteworthy miRNAs associated with WMLs were identified, primarily moderated by the factors of sex or smoking status. All identified miRNAs exhibited a strong over-representation in neurodegenerative and neurological diseases. We introduced hsa-miR-425-5p as a promising candidate in WML research probably involved in immunological processes. Mir-425-5p holds the potential as a biomarker of WMLs, shedding light on potential mechanisms and pathways in vascular dementia.

Therapeutic Impact of Aerobic Exercise on Adolescents with Obesity and Its Association with Expression of miRNAs and Cytokines: A Clinical Approach.

Background and Objectives: MicroRNAs are short noncoding RNAs that play an essential role in controlling gene expression at the posttranscriptional level. They can serve as biomarkers in the management of obesity. Circulating miRNAs levels change with exercise, impacting various physiological and biological systems, including structural and functional changes. Aim: The purpose of this study is to evaluate the levels of miRNAs 423-5p and 128-1 in young adolescents with obesity before and after an aerobic exercise programme. We also analyse the relationship between those microRNAs and obesity-related parameters in response to aerobic exercise training. Materials and Methods: A total of 64 adolescent individuals (32 individuals with obesity and 32 healthy individuals) were enrolled in the study to participate in a 6-month aerobic exercise programme. Anthropometric measurements, biochemical parameters and blood samples were collected from all the participants prior to exercise training and after the 6-month programme. Gene expression analysis of the study participants was performed using quantitative real-time PCR. Results: Expression levels of circulating microRNAs 423-5p (p < 0.01) and 128-1 (p < 0.01) differed significantly before and after exercise in the study population. Circulating miRNA 423-5p increased and correlated significantly with BMI while circulating miRNA 128-1 decreased and also significantly correlated with BMI after the 6-month aerobic exercise programme. Logistic regression analysis shows that the elevation in miRNAs expression levels has a strong significant association with the increased levels of the cytokines IL-6 and TNF-α (p < 0.05). Conclusions: Obesity leads to alterations in the expressions of miRNA 423-5p and miRNA 128-1. The significant changes observed after an aerobic exercise programme demonstrate the potential of these miRNAs as diagnostic and prognostic biomarkers for obesity.

Plasma Levels of mir-34a-5p Correlate with Systemic Inflammation and Low Naïve CD4 T Cells in Common Variable Immunodeficiency.

PURPOSE: Common variable immunodeficiency (CVID) is a primary antibody deficiency that commonly manifests as recurrent infections. Many CVID patients also suffer from immune dysregulation, an inflammatory condition characterized by polyclonal lymphocytic tissue infiltration and associated with increased morbidity and mortality. The genetic cause is unknown in most CVID patients and epigenetic alterations may contribute to the broad range of clinical manifestations. MicroRNAs are small non-coding RNAs that are involved in epigenetic modulation and may contribute to the clinical phenotype in CVID. METHODS: Here, we determined the circulating microRNAome and plasma inflammatory proteins of a cohort of CVID patients with various levels of immune dysregulation and compared them to healthy controls. A set of deregulated microRNAs was validated by qPCR and correlated to inflammatory proteins and clinical findings. RESULTS: Levels of microRNA-34a correlated with 11 proteins such as CXCL9, TNF, and IL10, which were predicted to be biologically connected. Moreover, there was a negative correlation between mir-34 levels and the number of naïve CD4 T cells in CVID. CONCLUSION: Collectively, our data show that microRNAs correlate with the inflammatory response in CVID. Further investigations are needed to elucidate the role of miRNAs in the development of CVID-related immune dysregulation.

Circulating miR-26b-5p and miR-451a as diagnostic biomarkers in medullary thyroid carcinoma patients.

PURPOSE/METHODS: The determination of tumour biomarkers is paramount to advancing personalized medicine, more so in rare tumours like medullary thyroid carcinoma (MTC), whose diagnosis is still challenging. The aim of this study was to identify non-invasive circulating biomarkers in MTC. To achieve this goal, paired MTC tissue and plasma extracellular vesicle samples were collected from multiple centres and microRNA (miRNA) expression levels were evaluated. RESULTS: The samples from a discovery cohort of 23 MTC patients were analysed using miRNA arrays. Lasso logistic regression analysis resulted in the identification of a set of circulating miRNAs as diagnostic biomarkers. Among them, miR-26b-5p and miR-451a, were highly expressed and their expression decreased during follow-up in disease-free patients in the discovery cohort. Circulating miR-26b-5p and miR-451a were validated using droplet digital PCR in a second independent cohort of 12 MTC patients. CONCLUSION: This study allowed the identification and validation of a signature of two circulating miRNAs, miR-26b-5p and miR-451a, in two independent cohorts reporting a significant diagnostic performance for MTC. The results of this study offer advancements in molecular diagnosis of MTC proposing a novel non-invasive tool to use in precision medicine.

Diagnostic and prognostic value of miR-486-5p, miR-451a, miR-21-5p and monocyte to high-density lipoprotein cholesterol ratio in patients with acute myocardial infarction.

Acute myocardial infarction (AMI) is one of the most serious complications of coronary heart disease. Although morbidity and mortality have been decreasing year by year, acute coronary syndrome still has a high mortality rate and disability rate. To search for accurate and effective biomarkers, we explore the diagnostic and prognostic value of microRNAs (miRNAs) and the monocyte to high-density lipoprotein cholesterol ratio (MHR) in patients with AMI. By referring to the relevant literature, miR-486-5p, miR-451a and miR-21-5p were reportedly altered in the blood of patients with ischemic heart disease. These miRNAs were selected and validated in 40 AMI patients, 22 unstable angina pectoris (UAP) and 22 healthy groups (HC) by real-time fluorescent quantitative polymerase chain reaction (RT-qPCR). All patients with AMI underwent primary percutaneous coronary intervention (PCI) and were followed up 3 months after the operation. MHR and miR-451a expression were markedly elevated in plasma samples of AMI patients compared with the UAP and HC groups, but the expressions of miR-486-5p and miR-21-5p were significantly decreased. The expression level of miRNA-451a increased gradually among the three groups (p < 0.05). However, the expression of miRNA-21-5p showed a downward trend (p < 0.05). More importantly, MHR was significantly different before and after PCI in AMI patients (p < 0.05). Receiver operating characteristic (ROC) analysis indicated that MHR, miR-486-5p, miR-451a and miR-21-5p could diagnose and predict AMI. MiR-451a was a more reliable biomarker for AMI diagnosis among these miRNAs. Moreover, the combination of MHR and miRNAs had higher diagnostic value for AMI. We further demonstrated that miR-21-5p had a strong predictive ability for the occurrence of major adverse cardiovascular events (MACE) after 3 months. The results showed that circulating miR-486-5p, miR-451a, miR-21-5p and MHR may play critical roles in the early phase of AMI, and may be used as potential predictors for AMI diagnosis. Importantly, miR-451a was a more reliable biomarker in diagnosing AMI patients. Circulating miR-21-5p may be used as a predictor of MACE occurrence.

Circulating miR-206 and miR-1246 as Markers in the Early Diagnosis of Lung Cancer in Patients with Chronic Obstructive Pulmonary Disease.

Lung cancer (LC) is the most common cause of cancer death, with 75% of cases being diagnosed in late stages. This study aimed to determine potential miRNAs as biomarkers for the early detection of LC in chronic obstructive pulmonary disease (COPD) cases. Ninety-nine patients were included, with registered clinical and lung function parameters followed for 6 years. miRNAs were determined in 16 serum samples from COPD patients (four with LC and four controls) by next generation sequencing (NGS) at LC diagnosis and 3 years before. The validation by qPCR was performed in 33 COPD-LC patients and 66 controls at the two time points. Over 170 miRNAs (≥10 TPM) were identified; among these, miR-224-5p, miR-206, miR-194-5p, and miR-1246 were significantly dysregulated (p < 0.001) in COPD-LC 3 years before LC diagnosis when compared to the controls. The validation showed that miR-1246 and miR-206 were differentially expressed in COPD patients who developed LC three years before (p = 0.035 and p = 0.028, respectively). The in silico enrichment analysis showed miR-1246 and miR-206 to be linked to gene mediators in various signaling pathways related to cancer. Our study demonstrated that miR-1246 and miR-206 have potential value as non-invasive biomarkers of early LC detection in COPD patients who could benefit from screening programs.

Exploring the Feasibility of Circulating miRNAs as Diagnostic and Prognostic Biomarkers in Osteoarthritis: Challenges and Opportunities.

Osteoarthritis (OA) is a prevalent degenerative joint disease characterized by progressive cartilage degradation and joint inflammation. As the most common aging-related joint disease, OA is marked by inadequate extracellular matrix synthesis and the breakdown of articular cartilage. However, traditional diagnostic methods for OA, relying on clinical assessments and radiographic imaging, often need to catch up in detecting early-stage disease or i accurately predicting its progression. Consequently, there is a growing interest in identifying reliable biomarkers that can facilitate early diagnosis and prognosis of OA. MicroRNAs (miRNAs) have emerged as potential candidates due to their involvement in various cellular processes, including cartilage homeostasis and inflammation. This review explores the feasibility of circulating miRNAs as diagnostic and prognostic biomarkers in OA, focusing on knee OA while shedding light on the challenges and opportunities associated with their implementation in clinical practice.

Exploring the Potential Role of Circulating microRNAs as Biomarkers for Predicting Clinical Response to Neoadjuvant Therapy in Breast Cancer.

Breast cancer (BC) is a leading cause of cancer-related deaths among women worldwide. Neoadjuvant therapy (NAT) is increasingly being used to reduce tumor burden prior to surgical resection. However, current techniques for assessing tumor response have significant limitations. Additionally, drug resistance is commonly observed, raising a need to identify biomarkers that can predict treatment sensitivity and survival outcomes. Circulating microRNAs (miRNAs) are small non-coding RNAs that regulate gene expression and have been shown to play a significant role in cancer progression as tumor inducers or suppressors. The expression of circulating miRNAs has been found to be significantly altered in breast cancer patients. Moreover, recent studies have suggested that circulating miRNAs can serve as non-invasive biomarkers for predicting response to NAT. Therefore, this review provides a brief overview of recent studies that have demonstrated the potential of circulating miRNAs as biomarkers for predicting the clinical response to NAT in BC patients. The findings of this review will strengthen future research on developing miRNA-based biomarkers and their translation into medical practice, which could significantly improve the clinical management of BC patients undergoing NAT.

Alterations in Circulating miRNA Levels after Infection with SARS-CoV-2 Could Contribute to the Development of Cardiovascular Diseases: What We Know So Far.

The novel coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and poses significant complications for cardiovascular disease (CVD) patients. MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression and influence several physiological and pathological processes, including CVD. This critical review aims to expand upon the current literature concerning miRNA deregulation during the SARS-CoV-2 infection, focusing on cardio-specific miRNAs and their association with various CVDs, including cardiac remodeling, arrhythmias, and atherosclerosis after SARS-CoV-2 infection. Despite the scarcity of research in this area, our findings suggest that changes in the expression levels of particular COVID-19-related miRNAs, including miR-146a, miR-27/miR-27a-5p, miR-451, miR-486-5p, miR-21, miR-155, and miR-133a, may be linked to CVDs. While our analysis did not conclusively determine the impact of SARS-CoV-2 infection on the profile and/or expression levels of cardiac-specific miRNAs, we proposed a potential mechanism by which the miRNAs mentioned above may contribute to the development of these two pathologies. Further research on the relationship between SARS-CoV-2, CVDs, and microRNAs will significantly enhance our understanding of this connection and may lead to the use of these miRNAs as biomarkers or therapeutic targets for both pathologies.

OncoUroMiR: Circulating miRNAs for Detection and Discrimination of the Main Urological Cancers Using a ddPCR-Based Approach.

The three most common genitourinary malignancies (prostate/kidney/bladder cancers) constitute a substantial proportion of all cancer cases, mainly in the elderly population. Early detection is key to maximizing the patients' survival, but the lack of highly accurate biomarkers that might be used through non-/minimally invasive methods has impaired progress in this domain. Herein, we sought to develop a minimally invasive test to detect and discriminate among those urological cancers based on miRNAs assessment through ddPCR. Plasma samples from 268 patients with renal cell (RCC; n = 119), bladder (BlCa; n = 73), and prostate (PCa; n = 76) carcinomas (UroCancer group), and 74 healthy donors were selected. Hsa-miR-126-3p, hsa-miR-141-3p, hsa-miR-153-5p, hsa-miR-155-5p, hsa-miR-182-5p, hsa-miR-205-5p, and hsa-miR-375-3p levels were assessed. UroCancer cases displayed significantly different circulating hsa-miR-182-5p/hsa-miR-375-3p levels compared to healthy donors. Importantly, the hsa-miR-155-5p/hsa-miR-375-3p panel detected RCC with a high specificity (80.54%) and accuracy (66.04%). Furthermore, the hsa-miR-126-3p/hsa-miR-375-3p panel identified BlCa with a 94.87% specificity and 76.45% NPV whereas higher hsa-miR-126-3p levels were found in PCa patients. We concluded that plasma-derived miRNAs can identify and discriminate among the main genitourinary cancers, with high analytical performance. Although validation in a larger cohort is mandatory, these findings demonstrate that circulating miRNA assessment by ddPCR might provide a new approach for early detection and risk stratification of the most common urological cancers.

Circulating microRNAs as Potential Biomarkers in Pancreatic Cancer-Advances and Challenges.

There is an urgent unmet need for robust and reliable biomarkers for early diagnosis, prognosis, and prediction of response to specific treatments of many aggressive and deadly cancers, such as pancreatic cancer, and liquid biopsy-based miRNA profiling has the potential for this. MiRNAs are a subset of non-coding RNAs that regulate the expression of a multitude of genes post-transcriptionally and thus are potential diagnostic, prognostic, and predictive biomarkers and have also emerged as potential therapeutics. Because miRNAs are involved in the post-transcriptional regulation of their target mRNAs via repressing gene expression, defects in miRNA biogenesis pathway and miRNA expression perturb the expression of a multitude of oncogenic or tumor-suppressive genes that are involved in the pathogenesis of various cancers. As such, numerous miRNAs have been identified to be downregulated or upregulated in many cancers, functioning as either oncomes or oncosuppressor miRs. Moreover, dysregulation of miRNA biogenesis pathways can also change miRNA expression and function in cancer. Profiling of dysregulated miRNAs in pancreatic cancer has been shown to correlate with disease diagnosis, indicate optimal treatment options and predict response to a specific therapy. Specific miRNA signatures can track the stages of pancreatic cancer and hold potential as diagnostic, prognostic, and predictive markers, as well as therapeutics such as miRNA mimics and miRNA inhibitors (antagomirs). Furthermore, identified specific miRNAs and genes they regulate in pancreatic cancer along with downstream pathways can be used as potential therapeutic targets. However, a limited understanding and validation of the specific roles of miRNAs, lack of tissue specificity, methodological, technical, or analytical reproducibility, harmonization of miRNA isolation and quantification methods, the use of standard operating procedures, and the availability of automated and standardized assays to improve reproducibility between independent studies limit bench-to-bedside translation of the miRNA biomarkers for clinical applications. Here I review recent findings on miRNAs in pancreatic cancer pathogenesis and their potential as diagnostic, prognostic, and predictive markers.

Effects of a short-term cold exposure on circulating microRNAs and metabolic parameters in healthy adult subjects.

This discovery study investigated in healthy subjects whether a short-term cold exposure may alter circulating microRNAs and metabolic parameters and if co-expression networks between these factors could be identified. This open randomized crossover (cold vs no cold exposure) study with blind end- point evaluation was conducted at 1 center with 10 healthy adult male volunteers. Wearing a cooling vest perfused at 14°C for 2 h reduced the local skin temperature without triggering shivering, increased norepinephrine and blood pressure while decreasing copeptin, C-peptide and heart rate. Circulating microRNAs measured before and after wearing the cooling vest twice (4 time points) identified 196 mature microRNAs with excellent reproducibility over 72 h. Significant correlations of microRNA expression with copeptin, norepinephrine and C-peptide were found. A co-expression-based microRNA-microRNA network, as well as microRNA pairs displaying differential correlation as a function of temperature were also detected. This study demonstrates that circulating miRNAs are differentially expressed and coregulated upon cold exposure in humans, supporting their use as predictive and dynamic biomarkers of cardio-metabolic disorders.

Extracellular miRNAs as mediators of obesity-associated disease.

Extracellular miRNAs are found in a variety of body fluids and mediate intercellular and interorgan communication, thus regulating gene expression and cellular metabolism. These miRNAs are secreted either in small vesicles/exosomes (sEV) or bound to proteins such as Argonaute and high-density lipoprotein. Both exosomal and protein-bound circulating miRNAs are altered in obesity. Although all tissues can contribute to changes in circulating miRNAs, adipose tissue itself is an important source of these miRNAs, especially those in sEVs. These are derived from both adipocytes and macrophages and participate in crosstalk between these cells, as well as peripheral tissues, including liver, skeletal muscle and pancreas, whose function may be impaired in obesity. Changes in levels of circulating miRNAs have also been linked to the beneficial effects induced by weight loss interventions, including diet, exercise and bariatric surgery, further indicating a role for these miRNAs as mediators of disease pathogenesis. Here, we review the role of circulating miRNAs in the pathophysiology of obesity and explore their potential use as biomarkers and in therapy of obesity-associated metabolic syndrome.

Natural history of circulating miRNAs in Duchenne disease: Association with muscle injury and metabolic parameters.

OBJECTIVES: This study aimed to evaluate whether the expression of circulating dystromiRs and a group of oxidative stress-related (OS-R) miRNAs is associated with muscle injury and circulating metabolic parameters in Duchenne muscular dystrophy (DMD) patients. METHODS: Twenty-four DMD patients were included in this cross-sectional study. Clinical scales to evaluate muscle injury (Vignos, GMFCS, Brooke, and Medical Research Council), enzymatic muscle injury parameters (CPK, ALT, and AST), anthropometry, metabolic indicators, physical activity, serum dystromiRs (miR-1-3p, miR-133a-3p, and miR-206), and OS-R miRNAs (miR-21-5p, miR-31-5p, miR-128-3p, and miR-144-3p) levels were measured in ambulatory and non-ambulatory DMD patients. RESULTS: DystromiRs (except miR-1-3p) and miRNAs OS-R levels were lower (p-value <.05) in the non-ambulatory group than the ambulatory group. The expression of those miRNAs correlated with Vignos scale score (For instance, rho = -0.567, p-value <0.05 for miR-21-5p) and with other scales scores of muscle function and strength. CPK, AST, and ALT concentration correlated with expression of all miRNAs (For instance, rho = 0.741, p-value <.05 between miR-206 level and AST concentration). MiR-21-5p level correlated with glucose concentration (rho = -0.369, p-value = .038), and the miR-1-3p level correlated with insulin concentration (rho = 0.343, p-value = .05). CONCLUSIONS: Non-ambulatory DMD patients have lower circulating dystromiRs and OS-R miRNAs levels than ambulatory DMD patients. The progressive muscle injury is associated with a decrease in the expression of those miRNAs, evidencing DMD progress. These findings add new information about the natural history of DMD.