MicroRNA-126 and micro-/macrovascular complications of type 1 diabetes in the EURODIAB Prospective Complications Study

Serum MicroRNA-191-5p Levels in Vascular Complications of Type 1 Diabetes: The EURODIAB Prospective Complications Study

CONTEXT

MicroRNA-191-5p regulates key cellular processes involved in the pathogenesis of diabetic complications such as angiogenesis, extracellular matrix deposition, and inflammation. However, no data on circulating microRNA-191-5p in the chronic complications of diabetes are available.

OBJECTIVE

To assess whether serum levels of microRNA-191-5p were associated with micro- and macrovascular disease in a large cohort of subjects with type 1 diabetes mellitus (DM1) from the EURODIAB Prospective Complication Study.

DESIGN AND SETTING

Levels of microRNA-191-5p were measured by quantitative PCR in 420 patients with DM1 recruited as part of the cross-sectional analysis of the EURODIAB Prospective Complication Study. Cases (n = 277) were subjects with nephropathy and/or retinopathy and/or cardiovascular disease (CVD). Controls (n = 143) were patients without complications. Logistic regression analysis was performed to evaluate the potential independent association of microRNA-191-5p levels with chronic complications of diabetes.

RESULTS

Levels of microRNA-191-5p were significantly reduced (P < .001) in cases compared with controls even after adjustment for age, sex, and diabetes duration. Logistic regression analysis revealed that microRNA-191-5p was negatively associated with a 58% reduced odds ratio (OR) of chronic diabetes complications, specifically CVD, micro-macroalbuminuria, and retinopathy (OR, 0.42; 95% CI, 0.23-0.77), independent of age, sex, physical activity, educational levels, diabetes duration, glycated hemoglobin, total insulin dose, hypertension, smoking, total cholesterol, albumin excretion rate, estimated glomerular filtration rate, serum vascular cell adhesion molecule-1, and tumor necrosis factor-α. Analyses performed separately for each complication demonstrated a significant independent association with albuminuria (OR, 0.36; 95% CI, (0.18-0.75) and CVD (OR, 0.34; 95% CI, 0.16-0.70).

CONCLUSIONS

In DM1 subjects, microRNA-191-5p is inversely associated with vascular chronic complications of diabetes.

Exploring the theranostic potentials of miRNA and epigenetic networks in autoimmune diseases: A comprehensive review

BACKGROUND

Autoimmune diseases (AD) are severe pathophysiological ailments that are stimulated by an exaggerated immunogenic response towards self-antigens, which can cause systemic or site-specific organ damage. An array of complex genetic and epigenetic facets majorly contributes to the progression of AD, thus providing significant insight into the regulatory mechanism of microRNA (miRNA). miRNAs are short, non-coding RNAs that have been identified as essential contributors to the post-transcriptional regulation of host genome expression and as crucial regulators of a myriad of biological processes such as immune homeostasis, T helper cell differentiation, central and peripheral tolerance, and immune cell development.

AIMS

This article tends to deliberate and conceptualize the brief pathogenesis and pertinent epigenetic regulatory mechanism as well as miRNA networks majorly affecting five different ADs namely rheumatoid arthritis (RA), type 1 diabetes, multiple sclerosis (MS), systemic lupus erythematosus (SLE) and inflammatory bowel disorder (IBD) thereby providing novel miRNA-based theranostic interventions.

RESULTS & DISCUSSION

Pertaining to the differential expression of miRNA attributed in target tissues and cellular bodies of innate and adaptive immunity, a paradigm of scientific expeditions suggests an optimistic correlation between immunogenic dysfunction and miRNA alterations.

CONCLUSION

Therefore, it is not astonishing that dysregulations in miRNA expression patterns are now recognized in a wide spectrum of disorders, establishing themselves as potential biomarkers and therapeutic targets. Owing to its theranostic potencies, miRNA targets have been widely utilized in the development of biosensors and other therapeutic molecules originating from the same.

Cardiac angiogenesis enhances by activating Mir-126 and related target proteins in type 2 diabetic rats: Rescue combination effect of Sodium butyrate and voluntary exercise therapy

Objective

type 2 diabetes, metabolic disorder, is one of the main risk factors for cardiovascular disease, leading to angiogenesis injury. The present study wanted to discover the effect of sodium butyrate (NaB) and voluntary exercise, alone or together, on miR-126 and related proteins in rats with type 2 diabetes.

Methods

thirty-five male Wistar rats (200-250 g) were randomly divided into five groups: control, diabetes, diabetes-NaB, diabetes-exercise, and diabetes-NaB-exercise. Type 2 diabetes was induced by intraperitoneal injection of streptozotocin (35 mg/kg) and high-fat diet. The rats were then administrated NaB (200 mg/kg. ip) or were subjected to voluntary exercise, or combined NaB and voluntary exercise for 8 weeks. MiR-126 expression in the cardiac tissue was determined by real-time PCR, and the SPRED-1 and RAF proteins expression levels were measured by western blot.

Results

NaB and voluntary exercise up-regulated cardiac miR-126 and RAF expression levels and down-regulated SPRED-1 in cardiac tissue of type 2 diabetic rats. Moreover, the combination of NaB and voluntary exercise amplified their effects on those parameters. Both NaB and voluntary exercise or together markedly modulated serum glucose and HbA1c.

Conclusion

The present findings demonstrated that NaB combined with exercise could improve cardiac angiogenesis by increasing miR-126 and affecting related proteins. Thus, NaB together with voluntary exercise might be a promising intervention for the treatment and prevention of type 2 diabetes.

Intestinal microbiome diversity of diabetic and non-diabetic kidney disease: Current status and future perspective

A significant portion of the health burden of diabetic kidney disease (DKD) is caused by both type 1 and type 2 diabetes which leads to morbidity and mortality globally. It is one of the most common diabetic complications characterized by loss of renal function with high prevalence, often leading to acute kidney disease (AKD). Inflammation triggered by gut microbiota is commonly associated with the development of DKD. Interactions between the gut microbiota and the host are correlated in maintaining metabolic and inflammatory homeostasis. However, the fundamental processes through which the gut microbiota affects the onset and progression of DKD are mainly unknown. In this narrative review, we summarised the potential role of the gut microbiome, their pathogenicity between diabetic and non-diabetic kidney disease (NDKD), and their impact on host immunity. A well-established association has already been seen between gut microbiota, diabetes and kidney disease. The gut-kidney interrelationship is confirmed by mounting evidence linking gut dysbiosis to DKD, however, it is still unclear what is the real cause of gut dysbiosis, the development of DKD, and its progression. In addition, we also try to distinguish novel biomarkers for early detection of DKD and the possible therapies that can be used to regulate the gut microbiota and improve the host immune response. This early detection and new therapies will help clinicians for better management of the disease and help improve patient outcomes.

Pediatric Diabetic Nephropathy: Novel Insights from microRNAs

Diabetic nephropathy (DN) represents the most common microvascular complication in patients with diabetes. This progressive kidney disease has been recognized as the major cause of end-stage renal disease with higher morbidity and mortality. However, its tangled pathophysiology is still not fully known. Due to the serious health burden of DN, novel potential biomarkers have been proposed to improve early identification of the disease. In this complex landscape, several lines of evidence supported a critical role of microRNAs (miRNAs) in regulating posttranscriptional levels of protein-coding genes involved in DN pathophysiology. Indeed, intriguing data showed that deregulation of certain miRNAs (e.g., miRNAs 21, -25, -92, -210, -126, -216, and -377) were pathogenically linked to the onset and the progression of DN, suggesting not only a role as early biomarkers but also as potential therapeutic targets. To date, these regulatory biomolecules represent the most promising diagnostic and therapeutic options for DN in adult patients, while similar pediatric evidence is still limited. More, findings from these elegant studies, although promising, need to be deeper investigated in larger validation studies. In an attempt to provide a comprehensive pediatric overview in the field, we aimed to summarize the most recent evidence on the emerging role of miRNAs in pediatric DN pathophysiology.

Current Insights into miRNA and lncRNA Dysregulation in Diabetes: Signal Transduction, Clinical Trials and Biomarker Discovery

Diabetes is one of the most frequently occurring metabolic disorders, affecting almost one tenth of the global population. Despite advances in antihyperglycemic therapeutics, the management of diabetes is limited due to its complexity and associated comorbidities, including diabetic neuropathy, diabetic nephropathy and diabetic retinopathy. Noncoding RNAs (ncRNAs), including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), are involved in the regulation of gene expression as well as various disease pathways in humans. Several ncRNAs are dysregulated in diabetes and are responsible for modulating the expression of various genes that contribute to the 'symptom complex' in diabetes. We review various miRNAs and lncRNAs implicated in diabetes and delineate ncRNA biological networks as well as key ncRNA targets in diabetes. Further, we discuss the spatial regulation of ncRNAs and their role(s) as prognostic markers in diabetes. We also shed light on the molecular mechanisms of signal transduction with diabetes-associated ncRNAs and ncRNA-mediated epigenetic events. Lastly, we summarize clinical trials on diabetes-associated ncRNAs and discuss the functional relevance of the dysregulated ncRNA interactome in diabetes. This knowledge will facilitate the identification of putative biomarkers for the therapeutic management of diabetes and its comorbidities. Taken together, the elucidation of the architecture of signature ncRNA regulatory networks in diabetes may enable the identification of novel biomarkers in the discovery pipeline for diabetes, which may lead to better management of this metabolic disorder.

MicroRNA-150 (miR-150) and Diabetic Retinopathy: Is miR-150 Only a Biomarker or Does It Contribute to Disease Progression?

Diabetic retinopathy (DR) is a chronic disease associated with diabetes mellitus and is a leading cause of visual impairment among the working population in the US. Clinically, DR has been diagnosed and treated as a vascular complication, but it adversely impacts both neural retina and retinal vasculature. Degeneration of retinal neurons and microvasculature manifests in the diabetic retina and early stages of DR. Retinal photoreceptors undergo apoptosis shortly after the onset of diabetes, which contributes to the retinal dysfunction and microvascular complications leading to vision impairment. Chronic inflammation is a hallmark of diabetes and a contributor to cell apoptosis, and retinal photoreceptors are a major source of intraocular inflammation that contributes to vascular abnormalities in diabetes. As the levels of microRNAs (miRs) are changed in the plasma and vitreous of diabetic patients, miRs have been suggested as biomarkers to determine the progression of diabetic ocular diseases, including DR. However, few miRs have been thoroughly investigated as contributors to the pathogenesis of DR. Among these miRs, miR-150 is downregulated in diabetic patients and is an endogenous suppressor of inflammation, apoptosis, and pathological angiogenesis. In this review, how miR-150 and its downstream targets contribute to diabetes-associated retinal degeneration and pathological angiogenesis in DR are discussed. Currently, there is no effective treatment to stop or reverse diabetes-caused neural and vascular degeneration in the retina. Understanding the molecular mechanism of the pathogenesis of DR may shed light for the future development of more effective treatments for DR and other diabetes-associated ocular diseases.

Novel biomarkers for diabetic kidney disease

Although diabetic kidney disease (DKD) remains one of the leading causes of reduced lifespan in patients with diabetes mellitus; its prevalence has failed to decline over the past 30 years. To identify those at high risk of developing DKD and disease progression at an early stage, extensive research has been ongoing in the search for prognostic and surrogate endpoint biomarkers for DKD. Although biomarkers are not used routinely in clinical practice or prospective clinical trials, many biomarkers have been developed to improve the early identification and prognostication of patients with DKD. Novel biomarkers that capture one specific mechanism of the DKD disease process have been developed, and studies have evaluated the prognostic value of assay-based biomarkers either in small sets or in combinations involving multiple biomarkers. More recently, several studies have assessed the prognostic value of omics- based biomarkers that include proteomics, metabolomics, and transcriptomics. This review will first describe the biomarkers used in current practice and their limitations, and then summarize the current status of novel biomarkers for DKD with respect to assay- based protein biomarkers, proteomics, metabolomics, and transcriptomics.

Type 1 Diabetes Mellitus-Related circRNAs Regulate CD4+ T Cell Functions

Circular RNAs (circRNAs) participate in development of malignancies through its active role as a “miRNA sponge.” Their roles in type 1 diabetes mellitus (T1DM) pathogenesis are elusive. Here, the important role of circRNAs in T1DM was explored. circRNA profiling was performed for isolated CD4+ T cells from blood of T1DM and healthy volunteers. There were 257 differentially expressed circRNAs. Only three upregulated DEcircRNAs (hsa_circ_0000324, hsa_circ_0001853, and hsa_circ_0068797) were consistent with the GEO database. Through KEGG analyses, it was found that the three DEcircRNAs were associated with 11 miRNAs and 8 immune-related target genes (mRNA). Further analysis found that four miRNAs, two circRNAs, and four mRNAs were associated with nine circRNA-miRNA-mRNA networks. This confirmed the requirements of sponge mechanisms. The qRT-PCR analysis revealed that circRNA000324/miRNA675-5p/MAPK14 and circRNA000324/miRNA-675-5p/SYK may be potential mechanisms in regulation of differentiation and proliferation of CD4+ T cell in patients with T1DM. Therefore, targeting circRNA to regulate cellular immune responses by regulating CD4+ T cell differentiation may be a new strategy for the treatment of T1DM.

Association of serum MicroRNA-145-5p levels with microvascular complications of type 1 Diabetes: The EURODIAB prospective complications study

AIMS

To investigate whether serum miR-145-5p levels were associated with micro-macrovascular chronic complications in patients with type 1 diabetes (DM1).

METHODS

A nested case-control study from the EURODIAB Prospective Complications Study was performed. Cases (n = 289) had one or more complications of diabetes, whereas controls (n = 153) did not have any complication. We measured miR-145-5p levels by qPCR and investigated the association with diabetes complications.

RESULTS

Mean miR-145-5p levels were significantly lower in cases with microangiopathy [2.12 (0.86-4.94)] compared to controls [3.15 (1.21-7.36), P < 0.05] even after adjustment for age, gender, and diabetes duration. In logistic regression analysis, miR-145-5p levels in the lowest tertile were associated with an over three-fold increased odds ratio (OR) of albuminuria [3.22 (1.17-8.81)], independently of both demographic and diabetes-related factors. In addition, mir145-5p levels in the lowest tertile were independently and inversely associated with arterial hypertension [1.96 (1.08-3.56)] and hypertension was the mediator of the relationship between miR-145-5p and albuminuria.

CONCLUSIONS

In this large cohort of DM1 patients, we found an inverse association between miR-145-5p and albuminuria that was mediated by systemic hypertension.

Clinical application of microRNAs in glomerular diseases

RNA interference (RNAi) occurs in all organisms and modulates most, if not all, biological pathways. It is the process by which non-coding RNAs, including microRNAs (miRs), regulate gene transcription and post-transcriptional processing of messenger RNA (mRNA). A single miR can modulate several genes within a cell, and several miRs can regulate expression of the same gene, adding tiers of complexity to regulation of gene expression. MicroRNAs and other RNAi approaches have been successfully used in vitro and in vivo to selectively manipulate gene transcription, making them pivotal agents for basic science research and candidates for targeted therapeutics. This review will focus on miRs and their potential as biomarkers and novel therapeutics for glomerular disease.

Novel Markers in Diabetic Kidney Disease—Current State and Perspectives

Diabetic kidney disease (DKD) is a leading cause of end-stage renal disease. Along with the increasing prevalence of diabetes, DKD is expected to affect a higher number of patients. Despite the major progress in the therapy of DKD and diabetes mellitus (DM), the classic clinical diagnostic tools in DKD remain insufficient, delaying proper diagnosis and therapeutic interventions. We put forward a thesis that there is a need for novel markers that will be early, specific, and non-invasively obtained. The ongoing investigations uncover new molecules that may potentially become new markers of DKD—among those are: soluble α-Klotho and proteases (ADAM10, ADAM17, cathepsin, dipeptidyl peptidase 4, caspase, thrombin, and circulating microRNAs). This review summarizes the current clinical state-of-the-art in the diagnosis of DKD and a selection of potential novel markers, based on up-to-date literature.

Type 1 Diabetes and Associated Cardiovascular Damage: Contribution of Extracellular Vesicles in Tissue Crosstalk

Significance: Type 1 diabetes (T1D) is characterized by the autoimmune destruction of the insulin secreting β-cells, with consequent aberrant blood glucose levels. Hyperglycemia is the common denominator for most of the chronic diabetic vascular complications, which represent the main cause of life reduction in T1D patients. For this disease, three interlaced medical needs remain: understanding the underlying mechanisms involved in pancreatic β-cell loss; identifying biomarkers able to predict T1D progression and its related complications; recognizing novel therapeutic targets. Recent Advances: Extracellular vesicles (EVs), released by most cell types, were discovered to contain a plethora of different molecules (including microRNAs) with regulatory properties, which are emerging as mediators of cell-to-cell communication at the paracrine and endocrine level. Recent knowledge suggests that EVs may act as pathogenic factors, and be developed into disease biomarkers and therapeutic targets in the context of several human diseases. Critical Issues: EVs have been recently shown to sustain a dysregulated cellular crosstalk able to exacerbate the autoimmune response in the pancreatic islets of T1D; moreover, EVs were shown to be able to monitor and/or predict the progression of T1D and the insurgence of vasculopathies. Future Directions: More mechanistic studies are needed to investigate whether the dysregulation of EVs in T1D patients is solely reflecting the progression of diabetes and related complications, or EVs also directly participate in the disease process, thus pointing to a potential use of EVs as therapeutic targets/tools in T1D. Antioxid. Redox Signal. 36, 631-651.

Vitreous microparticles contain apoptotic signals suggesting a diabetic vitreopathy

AIM

To evaluate differences in microparticle profiles in vitreous samples between diabetic and non-diabetic eyes undergoing vitrectomy.

METHODS

Un-masked cross-sectional series of 34 eyes undergoing vitrectomy. Vitreous specimens were collected and processed to evaluate for membrane integrity (DAPI), apoptosis (Annexin-V), and endothelial-cell origin (V-Cadherin). A BD LSR II flow cytometer was used for analysis and standardized sub-micron-sized beads were used for size comparison.

RESULTS

Thirty-four specimens underwent analysis. Greater levels of Annexin-V were found on microparticles from specimens in which blood had entered the vitreous (n=12) compared to those without blood (n=22; 52.3%±30.7% vs 19.6%±27.2%, P=0.002). Patients with diabetes having surgery with hemorrhage (n=7) had greater expression of Annexin-V than those without hemorrhage (n=8; 62.1%±31.7% vs 18.9%±20.9%, P=0.009). However, in patients with non-diabetic vitreous hemorrhage, the level of Annexin-V expression was not significantly different compared to other disease processes (38.6%±25.7%, n=5 vs 20.0%±30.9%, n=14, P=0.087).

CONCLUSION

Increased expression of the apoptotic marker, Annexin-V is detected on vitreous microparticles in diabetes-related vitreous hemorrhage. When evaluating vitreous hemorrhage in patients without diabetes, the apoptotic signal is not significantly different. Vitrectomy in patients with diabetes, and improvement in visual outcomes, may be related to the removal of a serum-derived, pro-apoptotic vitreous. Further investigation is warranted in order to identify the molecular characteristics of microparticles that regulate disease.

The Dynamics and Plasticity of Epigenetics in Diabetic Kidney Disease: Therapeutic Applications Vis-à-Vis

Chronic kidney disease (CKD) refers to the phenomenon of progressive decline in the glomerular filtration rate accompanied by adverse consequences, including fluid retention, electrolyte imbalance, and an increased cardiovascular risk compared to those with normal renal function. The triggers for the irreversible renal function deterioration are multifactorial, and diabetes mellitus serves as a major contributor to the development of CKD, namely diabetic kidney disease (DKD). Recently, epigenetic dysregulation emerged as a pivotal player steering the progression of DKD, partly resulting from hyperglycemia-associated metabolic disturbances, rising oxidative stress, and/or uncontrolled inflammation. In this review, we describe the major epigenetic molecular mechanisms, followed by summarizing current understandings of the epigenetic alterations pertaining to DKD. We highlight the epigenetic regulatory processes involved in several crucial renal cell types: Mesangial cells, podocytes, tubular epithelia, and glomerular endothelial cells. Finally, we highlight epigenetic biomarkers and related therapeutic candidates that hold promising potential for the early detection of DKD and the amelioration of its progression.

Decreased Levels of miR-126 and miR-132 in Plasma and Vitreous Humor of Non-Proliferative Diabetic Retinopathy Among Subjects with Type-2 Diabetes Mellitus

PURPOSE

Diabetic retinopathy (DR), the leading cause of blindness among working adults, is an urgent public health problem as diabetes mellitus (DM) is increasing at an alarming rate. Hyperglycemia-induced endothelial dysfunction is the principal contributing factor leading to the development of microangiopathy. Altered levels of microRNA (miR), the negative regulator of protein-coding genes, have been observed and considered to be markers for DR. Present study aimed to find out whether miR levels in plasma could be effective biomarkers to differentiate between type 2 diabetes mellitus (T2DM) with non-proliferative retinopathy (NPDR) from T2DM with no-DR (DNR).

METHODS

We recruited 50 T2DM subjects comprising 31 NPDR and 19 DNR individuals. Surrogate markers of systemic oxidative stress and vascular endothelial growth factor (VEGF) were measured in plasma. Levels of miR-126 and miR-132 were determined in plasma and vitreous fluid using real-time PCR.

RESULTS

We observed that levels of miR-126 and miR-132 were decreased in NPDR subjects in comparison to DNR. Plasma levels of miRs were inversely correlated with secreted levels of VEGF and oxidative stress marker. The levels of these miRs showed discriminating ability between NPDR and DNR.

CONCLUSION

Circulating miRs 126 and 132 in plasma or vitreous may serve as biomarkers for early diabetic retinopathy risk prediction, provided validated in a larger cohort and other forms of retinal vasculopathy or retinopathy in the future.

MicroRNA 146a is associated with diabetic complications in type 1 diabetic patients from the EURODIAB PCS

Background

MicroRNA-146a-5p (miR-146a-5p) is a key regulator of inflammatory processes. Expression of miR-146a-5p is altered in target organs of diabetic complications and deficiency of miR-146a-5p has been implicated in their pathogenesis. We investigated if serum miR-146a-5p levels were independently associated with micro/macrovascular complications of type 1 diabetes (DM1).

Methods

A nested case–control study from the EURODIAB PCS of 447 DM1 patients was performed. Cases (n = 294) had one or more complications of diabetes, whereas controls (n = 153) did not have any complication. Total RNA was isolated from all subjects and miR-146a-5p levels measured by qPCR. Both the endogenous controls U6 snRNA and the spike (Cel-miR-39) were used to normalize the results. Logistic regression analysis was carried out to investigate the association of miR-146a-5p with diabetes complications.

Results

MiR-146a-5p levels were significantly lower in cases [1.15 (0.32–3.34)] compared to controls [1.74 (0.44–6.74) P = 0.039]. Logistic regression analysis showed that levels of miR-146a-5p in the upper quartile were inversely associated with reduced odds ratio (OR) of all complications (OR 0.34 [95% CI 0.14–0.76]) and particularly with cardiovascular diseases (CVD) (OR 0.31 [95% CI 0.11–0.84]) and diabetic retinopathy (OR 0.40 [95% CI 0.16–0.99]), independently of age, sex, diabetes duration, A1c, hypertension, AER, eGFR, NT-proBNP, and TNF-α.

Conclusions

In this large cohort of DM1 patients, we reported an inverse and independent association of miR-146a-5p with diabetes chronic complications and in particular with CVD and retinopathy, suggesting that miR-146a-5p may be a novel candidate biomarker of DM1 complications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03142-4.

Epigenetic Mechanisms in Type 2 Diabetes Retinopathy: A Systematic Review

Diabetic retinopathy (DR) is one of the main causes of vision loss in middle-aged economically active people. Modifiable (i.e., hyperglycaemia, hypertension, hyperlipidaemia, obesity, and cigarette smoke) and non-modifiable factors (i.e., duration of diabetes, puberty, pregnancy and genetic susceptibility) are involved in the development of DR. Epigenetic mechanisms, modulating the oxidative stress, inflammation, apoptosis, and aging, could influence the course of DR. Herein, we conducted a systematic review of observational studies investigating how epigenetics affects type 2 diabetes retinopathy (T2DR). A total of 23 epidemiological studies were included: 14 studies focused on miRNA, 4 studies on lnc-RNA, one study on both miRNA and lnc-RNA, and 4 studies on global or gene-specific DNA methylation. A direct relation between the dysregulation of miR-21, miR-93, and miR-221 and FPG, HbA1c, and HOMA-IR was identified. A panel of three miRNAs (hsa-let-7a-5p, hsa-miR-novel-chr5_15976, and hsa-miR-28-3p) demonstrated a good sensitivity and specificity for predicting T2DR. Little evidence is available regarding the possible role of the long non-coding MALAT1 dysregulation and MTHFR gene promoter hypermethylation. Despite these initial, encouraging findings potentially suggesting a role of epigenetics in T2DR, the use in clinical practice for the diagnosis and staging of this complication encounters several difficulties and further targeted investigations are still necessary.

Continuous subcutaneous insulin infusion alters microRNA expression and glycaemic variability in children with type 1 diabetes

To determine whether continuous subcutaneous insulin infusion (CSII) vs. multiple daily injections (MDI) therapy from near-diagnosis of type 1 diabetes is associated with reduced glycaemic variability (GV) and altered microRNA (miRNAs) expression. Adolescents (74% male) within 3-months of diabetes diagnosis (n = 27) were randomized to CSII (n = 12) or MDI. HbA1c, 1-5-Anhydroglucitol (1,5-AG), high sensitivity C-peptide and a custom TaqMan qPCR panel of 52 miRNAs were measured at baseline and follow-up (median (LQ-UQ); 535 (519–563) days). There were no significant differences between groups in baseline or follow-up HbA1c or C-peptide, nor baseline miRNAs. Mean ± SD 1,5-AG improved with CSII vs. MDI (3.1 ± 4.1 vs. − 2.2 ± − 7.0 mg/ml respectively, P = 0.029). On follow-up 11 miRNAs associated with diabetes vascular complications had altered expression in CSII-users. Early CSII vs. MDI use is associated with lower GV and less adverse vascular-related miRNAs. Relationships with future complications are of interest.

Clinical significance of serum miR-129-5p in patients with diabetes mellitus presenting macrovascular complications

BACKGROUND

Diabetic macrovascular complications (DMCs) are the most common complications encountered during the course of diabetes mellitus (DM) with extremely high mortality rates. Therefore, there is an urgent need to identify specific and sensitive biomarkers for the early diagnosis of DMCs.

AIM

To investigate the expression and significance of serum miR-129-5p in patients with DM and macrovascular complications.

METHODS

Serum samples were collected from 36 healthy controls, 58 patients with DM presenting no macrovascular complications, and 62 patients with DMCs. The expression of miR-129-5p was detected using quantitative real-time polymerase chain reaction. Pearson’s correlation assay was performed to analyze the correlation between serum miR-129-5p levels and clinical indicators. Receiver operator characteristic (ROC) analysis was conducted to analyze the diagnostic value of serum miR-129-5p in patients with DM or DMCs.

RESULTS

There was a 4.378-fold and 7.369-fold increase in serum miR-129-5p expression in the DM (5.346 ± 0.405) and DMCs (8.998 ± 0.631) groups, respectively (P < 0.001), compared with the control group (1.221±0.090). In addition, the expression of serum miR-129-5p in patients with DMCs was higher than that in patients with DM, revealing a 1.683-fold increase (P < 0.001). Additionally, serum miR-129-5p expression significantly correlated with smoking history, disease duration, and glycated hemoglobin (HbA1c) in patients with DMCs (P < 0.001). The area under the ROC curve (AUC) of miR-129-5p as a serum marker was 0.964 (95% confidence interval [CI]: 0.930-0.997, P < 0.001) in distinguishing between patients with DM and healthy controls, whereas the AUC of miR-129-5p as a serum marker was 0.979 (95%CI: 0.959-0.999, P < 0.001) in distinguishing between patients with DMCs and healthy controls.

CONCLUSION

Elevated serum miR-129-5p expression levels correlate with the development of DMCs and can be utilized as a novel early diagnostic biomarker for DM combined with macrovascular complications.

Involvement of miR-126 rs4636297 and miR-146a rs2910164 polymorphisms in the susceptibility for diabetic retinopathy: a case-control study in a type 1 diabetes population

BACKGROUND AND PURPOSE

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression. MiRNA-126 and miRNA-146a have been described as having abnormal expressions in diabetic retinopathy (DR) patients. Polymorphisms in genes codifying miRNAs (miRSNPs) may alter the expression of the corresponding miRNA and, thus, interfere with susceptibility to DR. Therefore, miRSNPs in miR-126 and miR-146a genes could be associated with DR susceptibility. The purpose of this study was to investigate the association between miR-126 rs4636297 (G/A) and miR-146a rs2910164 (G/C) miRSNPs and DR.

METHODS

This case-control study included 195 type 1 diabetes mellitus (T1DM) patients with DR (cases) and 215 patients without DR and with ≥10 years of T1DM (controls). MiRSNPs were genotyped by real-time PCR.

RESULTS

Genotype distributions of two analysed miRSNPs were in Hardy-Weinberg equilibrium in controls (p > 0.050). Frequencies of the miR-126 rs4636297 miRSNP were not significantly different between case and control groups (p = 0.169). However, after adjustment for age, glycated haemoglobin, triglycerides, estimated glomerular filtration rate and ethnicity, the A allele of this miRSNP was associated with protection for DR under additive [OR: 0.444 (95% CI: 0.211-0.936), p = 0.033] and dominant [OR: 0.512 (95% CI: 0.303-0.865), p = 0.012] inheritance models. Genotype and allele frequencies of miR-146a rs2910164 miRSNP did not differ between groups (p = 0.368 and p = 0.957), and this polymorphism was not associated with DR when assuming different inheritance models.

CONCLUSION

Our results suggest an association between the A allele of miR-126 rs4636297 miRSNP and protection for DR in a Southern Brazilian population.

MiR-126, IL-7, CXCR1/2 receptors, inflammation and circulating endothelial progenitor cells: The study on targets for treatment pathways in a model of subclinical cardiovascular disease (type 1 diabetes mellitus)

Background

Type 1 diabetes (T1DM) is associated with premature cardiovascular disease (CVD) and a pro-inflammatory state whilst the proangiogenic miR-126-3p/-5p may play a role in CVD. Animal studies established miR-126 to be pro-angiogenic. We hypothesised miR-126-3p/-5p are reduced in T1DM whilst pro-inflammatory cytokines are increased.

Methods

29 well controlled, T1DM patients without CVD and 20 healthy controls (HCs) were studied. MiR-126-3p/-5p were assayed in plasma and peripheral blood mononuclear cells (PBMCs) whilst Chemokine C-X-C Receptor 1/2 (CXCR1/2) mRNA in PBMCs by real-time quantitative PCR. Cytokines were assayed by the Mesoscale Discovery. Ingenuity Pathway Analysis (IPA) was used to predict target genes, cellular functions and pathological states regulated by miR-126-3p/-5p. IPA generated both direct and indirect causations between different targets and analysed whether these effects would be inhibitory or stimulatory based on the published evidence.

Results

T1DM patients had a relatively good diabetic control (HbA1c = 7.4 ± 0.7% or 57.3 ± 7.6 mmol/mol). Homeostatic cytokine IL-7, pro-inflammatory cytokines IL-8 and TNF-α, and vascular endothelial growth factor-C (VEGF-C) were increased in T1DM, versus HCs; p = 0.008, p = 0.003, p = 0.041 and p = 0.013 respectively. MiR-126-5p was significantly upregulated in PBMCs in T1DM versus HCs; p = 0.01, but not in plasma. MiR-126-3p was unchanged. CXCR1/2 were elevated in T1DM versus HCs; p = 0.009 and p < 0.001 respectively. MiR-126-5p was positively correlated with CXCR1/2, and with HbA1c whilst negatively correlated with circulating endothelial progenitor cells (CD34⁺CD133⁺CD45^dim) and fibronectin adhesion assay in a combined group of T1DM patients and HCs; p = 0.028 p = 0.049 p = 0.035 p = 0.047 and p = 0.004 respectively. IPA predicted miR-126-5p to be anti-inflammatory through the inhibition of chemokine C–C motif ligand 27, chymotrypsin-like elastase 2A and IL-7, whilst miR-126-3p had no direct anti-inflammatory effect. Simultaneously IPA predicted IL-7 as the most upstream cytokine target.

Conclusions

T1DM without apparent CVD or diabetic complications is an inflammatory state characterised not only by raised pro-inflammatory cytokines but also by increased receptor CXCR1/2 and miR-126-5p. MiR-126-5p upregulation may represent a compensatory response. Pro-miR-126-5p therapies or anti-IL-7 therapies may be a new option to reduce both inflammation and CVD risk in T1DM. Further research is required in a large prospective study in patients with T1DM.

Non-Coding RNA and Diabetic Kidney Disease

Diabetic kidney disease (DKD) is one of the most common chronic microvascular complications of diabetes. In addition to the characteristic clinical manifestations of proteinuria, it also has a complex pathological process that results from the combined effects of multiple factors involving the whole renal structure such as glomeruli, renal tubules, and blood vessels. Non-coding RNAs (ncRNA) are transcripts with no or low coding potential, among which micro RNA (miRNA) has been widely studied as a functional miRNA involved in regulation and a potential biomarker for disease prediction. The abundance of long coding RNA (lncRNA) in vivo is highly expressed with a certain degree of research progress, but the structural similarity makes the research still challenging. The research of circular RNA (circRNA) is still in its early stages. It is more relevant to the study to provide a more relevant link between diseases in the kidney and other tissues or organs. This classification review mainly summarized the biogenesis characteristics, the pathological mechanism of ncRNA-regulating diseases, the ways of ncRNA in the clinical prediction as a potential biomarker, and the interaction networks of ncRNA.

Mean Platelet Volume and Platelet Distribution Width Correlate with Microvascular Complications in Egyptian People with Type 2 Diabetes Mellitus

BACKGROUND

Type 2 diabetes is a part of metabolic syndrome associated with a higher risk of vascular complications. Diabetes is characterized by changes in platelet morphology, function, and platelet hyperactivity so, it's considered a prothrombotic condition. Morbidity and mortality in people with type 2 diabetes-related to micro and macrovascular complications. Novel biomarkers are needed to identify and treat people at higher risk.

OBJECTIVE

The main objective of this controlled cross-sectional study was to evaluate Platelet volume indices (PVI) in subjects with type 2 diabetes with and without complications in comparison to subjects without diabetes.

METHODS

Hundred and thirty-five subjects aged from 35 to 60 years were subdivided into 3 groups. Group A includes 55 subjects with type 2 diabetes with complications. Group B includes 45 subjects with type 2 diabetes without complications. Group C includes 35 normal healthy subjects. Detailed clinical history was taken. Also, PVI, fasting blood glucose (FBG), hemoglobin A1c, and creatinine were obtained.

RESULTS

Mean Platelet Volume (MPV), Platelet Distribution Width (PDW), Plateletcrit (PCT), and Platelet large cell ratio (P-LCR) were significantly higher among subjects with retinopathy, nephropathy, and neuropathy than other subjects with diabetes who didn't develop complications (P<0.001). At cutoff value > 11.9 fL, MPV have diagnostic sensitivity 80% and specificity 97.8%. Whereas PDW >16.9fL has a sensitivity of 74.5% and specificity of 100% for diabetic microvascular complications (retinopathy, nephropathy, and neuropathy).

CONCLUSION

MPV and PDW may be considered as possible biomarkers for the early detection of diabetic microvascular complications.

Exosomes from microRNA-126 overexpressing mesenchymal stem cells promote angiogenesis by targeting the PIK3R2-mediated PI3K/Akt signalling pathway

microRNA‐126 (miR‐126), an endothelial‐specific miRNA, is associated with vascular homeostasis and angiogenesis. However, the efficiency of miR‐126‐based treatment is partially compromised due to the low efficiency of miRNA delivery in vivo. Lately, exosomes have emerged as a natural tool for therapeutic molecule delivery. Herein, we investigated whether exosomes derived from bone marrow mesenchymal stem cells (BMMSCs) can be utilized to deliver miR‐126 to promote angiogenesis. Exosomes were isolated from BMMSCs overexpressed with miR‐126 (Exo‐miR‐126) by ultracentrifugation. In vitro study, Exo‐miR‐126 treatment promoted the proliferation, migration and angiogenesis of human umbilical vein endothelial cells (HUVECs). Furthermore, the gene/protein expression of angiogenesis‐related vascular endothelial growth factor (VEGF) and angiotensin‐1 (Ang‐1) were up‐regulated after incubation with Exo‐miR‐126. Additionally, the expression level of phosphoinositol‐3 kinase regulatory subunit 2 (PIK3R2) showed an inverse correlation with miR‐126 in HUVECs. Particularly, the Exo‐miR‐126 treatment contributed to enhanced angiogenesis of HUVECs by targeting PIK3R2 to activate the PI3K/Akt signalling pathway. Similarly, Exo‐miR‐126 administration profoundly increased the number of newly formed capillaries in wound sites and accelerated the wound healing in vivo. The results demonstrate that exosomes derived from BMMSCs combined with miR‐126 may be a promising strategy to promote angiogenesis.

Progression of Diabetic Complications in Subgroups of People with Long Term Diabetes Type 1 According to Clinical Course

AIMS

Prevention and prediction of microvascular complications are important aims of medical care in people with type 1 diabetes. Since the course of the disease is heterogenous, we tried to identify subgroups with specific risk profiles for microvascular complications.

METHODS

Retrospective analysis of a cohort of 285 people (22637 consultations) with >10 years of type 1 diabetes. Persons were grouped into slow (<15 years), fast (>15 years) and non progressors according to the average onset of microvascular complications. Generalized estimating equations for binary outcomes were applied and pseudo coefficients of determination were calculated.

RESULTS

Progression to microvascular disease was associated with age (OR: 1.034 [1.001-1.068]; p=0.04), diabetes duration (OR: 1.057 [1.021-1.094]; p=0.002), HbA_1c (OR: 1.035 [1.011-1.060]; p=0.005), BMI (OR: 0.928 [0.866-0.994]; p=0.034) and the social strata index (OR: 0.910 [0.830-0.998]; p=0.046). Generalized estimating equations predicted 31.02% and exclusion of HbA_1c marginally reduced the value to 28.88%. The proportion of patients with LADA was higher in fast than slow progressors [13 (26.5%) vs. 14 (11.9%); p=0.019]. A generalized estimating equation comparing slow to fast progressors revealed no significant markers.

CONCLUSION

In our analysis, we were able to confirm known risk factors for microvascular disease in people with type 1 diabetes. Overall, prediction of individual risk was difficult, the effect of individual markers minor and we could not find differences regarding slow or fast progression. We therefore emphasis the need for additional markers to predict individual risk for microvascular disease.

MicroRNA-1281 as a Novel Circulating Biomarker in Patients With Diabetic Retinopathy

Objective: Recently, the role of circulating miRNAs as non-invasive biomarkers for the identification and monitoring of diabetes microvascular complications has emerged. Herein, we aimed to: identify circulating miRNAs differentially expressed in patients with and without diabetic retinopathy (DR); examine their predictive value; and understand their pathogenic impact. Methods: Pooled serum samples from randomly selected matched patients with type 2 diabetes, either with or without DR, were used for initial serum miRNA profiling. Validation of the most relevant miRNAs was thereafter conducted by RT-qPCR in an extended sample of patients with DR and matched controls. Results: Following miRNA profiling, 43 miRNAs were significantly up- or down-regulated in patients with DR compared with controls. After individual validation, 5 miRNAs were found significantly overexpressed in patients with DR. One of them, miR-1281, was the most up-regulated and appeared to be specifically related to DR. Furthermore, secreted levels of miR-1281 were increased in high glucose-cultured retinal cells, and there was evidence of a potential link between glucose-induced miR-1281 up-regulation and DR. Conclusion: Our findings suggest miR-1281 as a circulating biomarker of DR. Also, they highlight the pathogenic significance of miR-1281, providing insights for a new potential target in treating DR.

MicroRNA and vascular pathology of the eye

Since the discovery of microRNAs just a few decades ago, our knowledge of these molecules and their potential as diagnostic biomarkers and therapeutic targets has significantly expanded. There is an ongoing discussion in the scientific community about the possibility of using microRNA for the diagnosis of cardiovascular diseases. It has been shown recently that levels of some microRNAs vary in vascular eye disorders, such as age-related macular degeneration and diabetic retinopathy. However, despite serious advances in our understanding of microRNA’s role in eye pathology, we still do not know whether it is possible to use microRNA as a biomarker for central retinal vein occlusion. Perhaps, the discovery of such candidate microRNAs will help in making the timely diagnosis and improve the quality of medical care in patients with retinal vein occlusion.

Oxidative Stress and New Pathogenetic Mechanisms in Endothelial Dysfunction: Potential Diagnostic Biomarkers and Therapeutic Targets

Cardiovascular diseases (CVD), including heart and pathological circulatory conditions, are the world's leading cause of mortality and morbidity. Endothelial dysfunction involved in CVD pathogenesis is a trigger, or consequence, of oxidative stress and inflammation. Endothelial dysfunction is defined as a diminished production/availability of nitric oxide, with or without an imbalance between endothelium-derived contracting, and relaxing factors associated with a pro-inflammatory and prothrombotic status. Endothelial dysfunction-induced phenotypic changes include up-regulated expression of adhesion molecules and increased chemokine secretion, leukocyte adherence, cell permeability, low-density lipoprotein oxidation, platelet activation, and vascular smooth muscle cell proliferation and migration. Inflammation-induced oxidative stress results in an increased accumulation of reactive oxygen species (ROS), mainly derived from mitochondria. Excessive ROS production causes oxidation of macromolecules inducing cell apoptosis mediated by cytochrome-c release. Oxidation of mitochondrial cardiolipin loosens cytochrome-c binding, thus, favoring its cytosolic release and activation of the apoptotic cascade. Oxidative stress increases vascular permeability, promotes leukocyte adhesion, and induces alterations in endothelial signal transduction and redox-regulated transcription factors. Identification of new endothelial dysfunction-related oxidative stress markers represents a research goal for better prevention and therapy of CVD. New-generation therapeutic approaches based on carriers, gene therapy, cardiolipin stabilizer, and enzyme inhibitors have proved useful in clinical practice to counteract endothelial dysfunction. Experimental studies are in continuous development to discover new personalized treatments. Gene regulatory mechanisms, implicated in endothelial dysfunction, represent potential new targets for developing drugs able to prevent and counteract CVD-related endothelial dysfunction. Nevertheless, many challenges remain to overcome before these technologies and personalized therapeutic strategies can be used in CVD management.

microRNA Expression Profiling Based on Microarray Approach in Human Diabetic Retinopathy: A Systematic Review and Meta-Analysis

Diabetes mellitus (DM) is one of the growing public health threats globally and as one of the common serious microvascular complications of DM, diabetic retinopathy (DR) is the leading cause of irreversible visual impairments and blindness. There is growing concern about the role of microRNAs (miRNAs) in the pathogenesis of DR. This meta-analysis was designed to collect those published miRNA expression profiling studies that compared the miRNA expression profiles in the biological samples of DR patients with those in the control group. Eight publications were finally included in the meta-analysis, and a total of 93 differentially expressed miRNAs were reported. Although six miRNAs were reported in at least two studies and with the consistent direction, after stratification by the type of biological samples, miR-320a was consistently reported to be upregulated in two serum sample-based studies and miR-423-5p was consistently reported to be upregulated in two vitreous humor sample-based studies. miR-27b was consistently reported to be downregulated in two serum sample-based studies. In conclusion, the results of this meta-analysis of human DR miRNAs' expression profiling studies might provide some clues of the potential biomarkers of DR. Further investigation of the mechanisms of miRNAs and more external validation studies are warranted with the aim of developing new diagnostic markers for preventing or reversing DR.

MicroRNAs in Vascular Eye Diseases

Since the discovery of the first microRNA (miRNA) decades ago, studies of miRNA biology have expanded in many biomedical research fields, including eye research. The critical roles of miRNAs in normal development and diseases have made miRNAs useful biomarkers or molecular targets for potential therapeutics. In the eye, ocular neovascularization (NV) is a leading cause of blindness in multiple vascular eye diseases. Current anti-angiogenic therapies, such as anti-vascular endothelial growth factor (VEGF) treatment, have their limitations, indicating the need for investigating new targets. Recent studies established the roles of various miRNAs in the regulation of pathological ocular NV, suggesting miRNAs as both biomarkers and therapeutic targets in vascular eye diseases. This review summarizes the biogenesis of miRNAs, and their functions in the normal development and diseases of the eye, with a focus on clinical and experimental retinopathies in both human and animal models. Discovery of novel targets involving miRNAs in vascular eye diseases will provide insights for developing new treatments to counter ocular NV.

Blood Co-Circulating Extracellular microRNAs and Immune Cell Subsets Associate with Type 1 Diabetes Severity

Immune cell subsets and microRNAs have been independently proposed as type 1 diabetes (T1D) diagnostic and/or prognostic biomarkers. Here, we aimed to analyze the relationships between peripheral blood circulating immune cell subsets, plasmatic microRNAs, and T1D. Blood samples were obtained from both children with T1D at diagnosis and age-sex matched healthy controls. Then, immunophenotype assessed by flow cytometry was coupled with the quantification of 60 plasmatic microRNAs by quantitative RT-PCR. The associations between immune cell frequency, plasmatic microRNAs, and the parameters of pancreatic loss, glycemic control, and diabetic ketoacidosis were assessed by logistic regression models and correlation analyses. We found that the increase in specific plasmatic microRNAs was associated with T1D disease onset (let-7c-5p, let-7d-5p, let-7f-5p, let-7i-5p, miR-146a-5p, miR-423-3p, and miR-423-5p), serum C-peptide concentration (miR-142-5p and miR-29c-3p), glycated hemoglobin (miR-26a-5p and miR-223-3p) and the presence of ketoacidosis (miR-29c-3p) more strongly than the evaluated immune cell subset frequency. Some of these plasmatic microRNAs were shown to positively correlate with numbers of blood circulating B lymphocytes (miR-142-5p) and CD4⁺CD45RO⁺ (miR-146a-5p and miR-223-3p) and CD4⁺CD25⁺ cells (miR-423-3p and miR-223-3p) in children with T1D but not in healthy controls, suggesting a disease-specific microRNA association with immune dysregulation in T1D. In conclusion, our results suggest that, while blood co-circulating extracellular microRNAs and immune cell subsets may be biologically linked, microRNAs may better provide powerful information about T1D onset and severity.

Endothelial Dysfunction in Diabetic Retinopathy

Diabetic retinopathy (DR) is a diabetic complication which affects retinal function and results in severe loss of vision and relevant retinal diseases. Retinal vascular dysfunction caused by multifactors, such as advanced glycosylation end products and receptors, pro-inflammatory cytokines and chemokines, proliferator-activated receptor-γ disruption, growth factors, oxidative stress, and microRNA. These factors promote retinal endothelial dysfunction, which results in the development of DR. In this review, we summarize the contributors in the pathophysiology of DR for a better understanding of the molecular and cellular mechanism in the development of DR with a special emphasis on retinal endothelial dysfunction.

Omics-based biomarkers in the diagnosis of diabetes

Diabetes mellitus (DM) is a group of metabolic diseases related to the dysfunction of insulin, causing hyperglycaemia and life-threatening complications. Current early screening and diagnostic tests for DM are based on changes in glucose levels and autoantibody detection. This review evaluates recent studies on biomarker candidates in diagnosing type 1, type 2 and gestational DM based on omics classification, whilst highlighting the relationship of these biomarkers with the development of diabetes, diagnostic accuracy, challenges and future prospects. In addition, it also focuses on possible non-invasive biomarker candidates besides common blood biomarkers.

MiR-126 targets IL-17A to enhance proliferation and inhibit apoptosis in high-glucose-induced human retinal endothelial cells

Diabetic retinopathy (DR) is a common complication of diabetes mellitus (DM), which results in vision loss. This study explored the role of miR-126 in high-glucose-induced human retinal endothelial cells (HRECs) and its underlying molecular mechanisms. The results showed that the expression levels of miR-126 and interleukin-17A (IL-17A) in high-glucose-induced HRECs were downregulated and upregulated, respectively. Functionally, overexpression of miR-126 promoted proliferation and suppressed apoptosis in high-glucose-induced HRECs, while IL-17A reversed the effects induced by miR-126. However, overexpression of IL-17A inhibited the proliferation and induced apoptosis, while knockdown of IL-17A accelerated the proliferation and repressed apoptosis. In addition, miR-126 repressed the expression of IL-17A, Bax, and caspase-3, while promoting the expression of survivin and phosphorylation of PI3K and AKT; restoration of IL-17A rescued these effects. Furthermore, IL-17A was identified as a target of miR-126. This indicates that miR-126 enhances proliferation and inhibits apoptosis in high-glucose-induced HRECs by activating the PI3K-AKT pathway, increasing survivin levels, and decreasing Bax and caspase-3 expression by targeting IL-17A, suggesting that miR-126 could be a novel target for preventing DR.

The circulating exosomal microRNAs related to albuminuria in patients with diabetic nephropathy

BACKGROUND

Diabetic nephropathy (DN) is associated with high risk of cardiovascular disease and mortality. Exosomal microRNAs (miRNAs) regulate gene expression in a variety of tissues and play important roles in the pathology of various diseases. We hypothesized that the exosomal miRNA profile would differ between DN patients and patients without nephropathy.

METHODS

We prospectively enrolled 74 participants, including healthy volunteers (HVs), diabetic patients without nephropathy, and those with DN. The serum exosomal miRNA profiles of participants were examined using RNA sequencing.

RESULTS

The expression levels of 107 miRNAs differed between HVs and patients without DN, whereas the expression levels of 95 miRNAs differed between HVs and patients with DN. Among these miRNAs, we found 7 miRNAs (miR-1246, miR-642a-3p, let-7c-5p, miR-1255b-5p, let-7i-3p, miR-5010-5p, miR-150-3p) that were uniquely up-regulated in DN patients compared to HVs, and miR-4449 that was highly expressed in DN patients compared to patients without DN. A pathway analysis revealed that these eight miRNAs are likely involved in MAPK signaling, integrin function in angiogenesis, and regulation of the AP-1 transcription factor. Moreover, they were all significantly correlated with the degree of albuminuria.

CONCLUSIONS

Patients with DN have a different serum exosomal miRNA profile compared to HVs. These miRNAs may be promising candidates for the diagnosis and treatment of DN and cardiovascular disease.

The low expression of circulating microRNA-19a represents an additional mortality risk in stable patients with vascular disease

BACKGROUND

Secondary prevention of atherosclerotic vascular diseases represents a cascade of procedures to reduce the risk of future fatal and non-fatal cardiovascular events. We sought to determine whether the expression of selected microRNAs influenced mortality of stable chronic cardiovascular patients.

METHODS

The plasma concentrations of five selected microRNAs (miR-1, miR-19, miR-126, miR-133 and miR-223) were quantified in 826 patients (mean age 65.2 years) with stable vascular disease (6-36 months after acute coronary syndrome, coronary revascularization or first-ever ischemic stroke). All-cause and cardiovascular mortality rates were followed during our prospective study.

RESULTS

Low expression (bottom quartile) of all five miRNAs was associated with a significant increase in five-year all-cause death, even when adjusted for conventional risk factors, treatment, raised troponin I and brain natriuretic protein levels [hazard risk ratios (HRRs) were as follows: miR-1, 1.65 (95% CI: 1.16-2.35); miR-19a, 2.27 (95% CI: 1.59-3.23); miR-126, 1.64 (95% CI: 1.15-2.33); miR-133a, 1.46 (95% CI: 1.01-2.12) and miR-223, 2.05 (95% CI: 1.45-2.91)]. Nearly similar results were found if using five-year cardiovascular mortality as the outcome. However, if entering all five miRNAs (along with other covariates) into a single regression model, only low miR-19a remained a significant mortality predictor; and only in patients with coronary artery disease [3.00 (95% CI: 1.77-5.08)], but not in post-stroke patients [1.63 (95% CI: 0.94-2.86)].

CONCLUSIONS

In stable chronic coronary artery disease patients, low miR-19a expression was associated with a substantial increase in mortality risk independently of other conventional cardiovascular risk factors.

MicroRNAs in the Progress of Diabetic Nephropathy: A Systematic Review and Meta-Analysis

Background

We conducted a systematic review and meta-analysis of existing literature to evaluate the different outcomes of microRNAs (miRNAs) in diabetic nephropathy (DN), including urinary albumin excretion rates, urinary albumin creatinine rates, glomerular filtration rate, HbAc1, and creatinine.

Methods

Electronic databases including PUBMED, MEDLINE, and EMBASE were searched for eligible publications to July 2018. The following comparisons between treatment groups were included: normal group versus DN group; control group versus micro/macroalbuminuria group.

Results

Twelve eligible studies that included 2500 participants were finally recruited in this meta-analysis. Fifteen miRNAs (miRNA-21, miRNA-181b, miRNA-194, miRNA-30, miRNA-215, and others) were upregulated whereas seven miRNAs (miRNA-26a, miRNA-126, miRNA-424, miRNA-574-3p, miR-223, miR-155, and miR-192) were downregulated in the DN group compared with control groups. The miR-133b, miR-342, miR-30, miR-192, miR-194, and miR-215 were significantly correlated in urinary albumin excretion rates (r=0.33, 95% CI= 0.26-0.39). miR-192, miR-217, miR-15b, miR-34a, and miR-636 were correlated with urinary albumin creatinine rates (r=0.69; 95% CI=0.12-0.92), while miR-133b, miR-345, miR-33, miR-326, miR-574-3p, miR-126, miR-217, miR-15b, miR-34a, and miR-636 were significantly correlated with HbAc1 (r =0.23, 95% CI = 0.15-0.31). There were twelve miRNAs that were closely related to the glomerular filtration rate (r=0.28, 95% CI =0.21-0.34). Creatinine (r=0.33, 95% CI = 0.22-0.40) was significantly different between normal and DN groups.

Conclusions

The meta-analysis acquired the correlations between miRNAs and outcomes including UAER, UACR, eGFR, HbAc1, and creatinine in DN. It suggested that miRNAs may participate in the pathogenesis of DN process.

The early detection of atherosclerosis in type 1 diabetes: why, how and what to do about it

The major cause of morbidity and often premature mortality in people with type I diabetes (T1D) is cardiovascular disease owing to accelerated atherosclerosis. We review publications relating to the rationale behind, and clinical tests for, detecting and treating early atherosclerosis in people with T1D. Currently available tools for atherosclerosis assessment include risk equations using vascular risk factors, arterial intima-media thickness, the ankle-brachial index, coronary artery calcification and angiography, and for more advanced lesions, intravascular ultrasound and optical coherence tomography. Evolving research tools include risk equations incorporating novel clinical, biochemical and molecular tests; vascular MRI and molecular imaging. As yet there is little information available to quantify early atherosclerosis. With better means to control the vascular risk factors, such as hypertension, dyslipidaemia and glycaemic control, and emerging therapies to control novel risk factors, further epidemiologic and clinical trials are merited to facilitate the translation into clinical practice of robust means to detect, monitor and treat early atherosclerosis in those with T1D.

MicroRNAs: new biomarkers and promising therapeutic targets for diabetic kidney disease

Diabetic kidney disease (DKD) is a chronic complication of diabetes mellitus associated with significant morbidity and mortality regarded as a global health issue. MicroRNAs - small RNA molecules responsible for the post-transcriptional regulation of gene expression by degradation of messenger RNA or translational repression of protein synthesis - rank among the factors linked to the development and progression of DKD. This study aimed to offer a narrative review on investigations around the use of microRNAs in the diagnosis, monitoring, and treatment of DKD. Various microRNAs are involved in the pathogenesis of DKD, while others have a role in nephroprotection and thus serve as promising therapeutic targets for DKD. Serum and urine microRNAs levels have also been considered in the early diagnosis and monitoring of individuals with DKD, since increases in albuminuria, decreases in the glomerular filtration rate, and progression of DKD have been linked to changes in the levels of some microRNAs.

MicroRNA-126: a promising biomarker for angiogenesis of diabetic wounds treated with negative pressure wound therapy

BACKGROUND

Negative pressure wound therapy represents an effective therapy to treat nonhealing diabetic wounds by promoting angiogenesis, of which the mechanism hasn't been investigated thoroughly. Growing evidence suggests that miRNAs hold great potential to be clinical biomarkers, and miR-126 is an essential angiogenesis regulator in diabetic wound repair.

PURPOSE

Our study aims to explore the effect of NPWT on the expression of miR-126 in the wound tissue and plasma of diabetic rat models and the association between circulating miR-126 and two quantitative indexes of angiogenesis.

METHODS

Full-thickness excisional wounds were created on the back of diabetic rats. Measure the wound closure and collect the wound tissue and blood for H&E, immunohistochemistry, Western blot and RT-PCR. Here we demonstrated that significantly increased capillary density and arteriolar density in the NPWT group at each specified time-point.

RESULTS

In the NPWT group, miR-126 expression was significantly increased on days 3, 5, 7, and 9 (P<0.05). Furthermore, statistically significant increases in VEGF mRNA and protein expression and p-ERK expression, as well as decreased SPRED1 expression, were noted upon treatment with NPWT on day 9. Our data revealed that miR-126 expression in the wound and plasma was significantly associated (P<0.05). Moreover, a positive correlation was also detected between increased levels of circulating miR-126 and arteriolar density, as well as capillary density (P<0.05).

CONCLUSION

The study suggested that miR-126 was upregulated by NPWT and could represent a promising monitoring tool for angiogenesis in diabetic wounds treated with NPWT.

GALLIC ACID IMPROVES OXIDATIVE STRESS AND INFLAMMATION THROUGH REGULATING MICRORNAS EXPRESSIONS IN THE BLOOD OF DIABETIC RATS

Context

Endothelial dysfunction and diabetic cardiomyopathy are critical complications of diabetes. Gallic acid (GA) plays a significant role in cardiovascular disorders resulted from diabetes. In addition, increased plasma miR-24, miR-126 associated with endothelial dysfunction.

Aim

The current study was designed to assess the effects of GA on plasma miR-24, miR-126 levels in the diabetic rats.

Animals and Methods

Adult male Sprague-Dawley rats were divided into three groups (n=8): control (C), diabetic (D) and diabetic group treated with GA (D+G, 25 mg/kg, by gavage) for eight weeks. The blood glucose level, body weight, lipid profile, blood pressure, plasma miR-24 and miR-126 levels, antioxidant and inflammatory biomarkers were measured.

Results

The plasma levels of miR-24, miR-126, body weight, high-density lipoprotein cholesterol (HDL-c), total anti-oxidant capacity (TAC) and the systolic blood pressure significantly reduced and blood glucose, total cholesterol (TC), triglycerides (TG), very low-density lipoprotein cholesterol (VLDL-c), malondialdehyde (MDA), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α) and low-density lipoprotein cholesterol (LDL-c) significantly elevated among the diabetic rats compared with the control group. However, GA restored body weight, blood pressure, TC, TG, VLDL-c, TNF-α, miR-126, blood glucose, HDL-c, MDA, TAC, miR-24 and IL-6 among the GA treated rats compared with the diabetic group.

Conclusion

GA improves inflammation, oxidative stress and hypotension result from diabetes. These protective effects are probably mediated via increasing plasma miR-24 and miR-126 levels.

Micro-RNAs 518d-3p and 618 Are Upregulated in Individuals With Type 1 Diabetes With Multiple Microvascular Complications

Objective: To compare the serum micro-RNAs (miRNAs) profile of individuals with type 1 diabetes without microvascular complications vs. those with multiple severe microvascular complications, in order to identify epigenetically modulated pathways in these two groups of individuals. Research Design and Methods: A total of 10 subjects were selected among individuals followed in the Diabetes Outpatient Clinic and sorted according to the absence or presence of all microvascular complications. Samples from these participants were used for evaluation of serum miRNA expression profile employing a qRT-PCR assay with hydrolysis probes based on the Taqman Low Density Arrays (TLDA) system. The top six most differentially expressed miRNAs between the aforementioned groups were validated by qRT-PCR in additional 47 type 1 diabetes individuals sorted according to the absence or presence of all microvascular complications and matched for age, sex, degree of metabolic control, diabetes duration, and age at diagnosis. Results: Twenty one out of three hundred and seventy seven miRNAs were upregulated in the group of individuals with all microvascular complications vs. the group without complications. The following miRs were validated: 518-3p, 34a-5p, 126-5p, 425-5p, 618, and 139-5p and logistic regression analyses showed that miRNA-518-3p and miRNA-618 were positively associated with multiple microvascular complications after adjustment for age, sex, diabetes duration, HbA₁c and use of statin, angiotensin-converting enzyme inhibitors and amlodipine. Conclusions: In this cohort of type 1 diabetes individuals, serum miR-518d-3p and miR-618 were upregulated in those with diabetes kidney disease, diabetes retinopathy, peripheral neuropathy, and cardiovascular autonomic neuropathy in comparison to individuals with no microvascular complications.

The Role of MicroRNAs in the Pathogenesis of Diabetic Nephropathy

Diabetic nephropathy (DN) is one of the most common microvascular complications in diabetic patients; it is also an important cause of renal dysfunction, renal fibrosis, and end-stage renal disease. Unfortunately, the pathogenesis of DN is complex and has not yet been fully elucidated; hence, the pathogenesis of DN to determine effective treatments of crucial importance is deeply explored. Early DN research focuses on hemodynamic changes and metabolic disorders, and recent studies have shown the regulatory role of microRNAs (miRNAs) in genes, which may be a new diagnostic marker and therapeutic target for diabetic nephropathy. In this review, we summarize the recent advances in the clinical value and molecular mechanisms of miRNAs in DN, providing new ideas for the diagnosis and treatment of DN.

The effects of microRNAs in activating neovascularization pathways in diabetic retinopathy

Diabetic retinopathy (DR) is one of the major complications of diabetes mellitus that causes diabetic macular edema and visual loss. DR is categorized, based on the presence of vascular lesions and neovascularization, into non-proliferative and proliferative DR. Vascular changes in DR correlate with the cellular damage and pathological changes in the capillaries of blood-retinal barrier. Several cytokines have been involved in inducing neovascularization. These cytokines activate different signaling pathways which are mainly responsible for the complications of DR. Recently; microRNAs (miRNAs) have been introduced as the key factors in the regulation of the cytokine expression which plays a critical role in neovascularization of retinal cells. Some studies have demonstrated that changing levels of miRNAs have essential role in the pathophysiology of vascular changes in patients with DR. The aim of this study is to identify the effects of miRNAs in the pathogenesis of DR via activating neovascularization pathways.

Endothelial dysfunction in diabetes and hypertension: Role of microRNAs and long non-coding RNAs

The vascular endothelium acts as a barrier between the blood flow and the inner lining of the vessel wall, and it functions as a filtering machinery to filter out any unwanted transfer of materials from both sides (i.e. the blood and the surrounding tissues). It is evident that diseases such as diabetes, obesity, and hypertension disturb the normal endothelial functions in humans and lead to endothelial dysfunction, which may further precede to the development of atherosclerosis. Long non-coding RNAs and micro RNAs both are types of non-coding RNAs which, in the recent years, have increasingly been studied in the pathophysiology of many diseases including diabetes, obesity, cardiovascular diseases, neurological diseases, and others. Recent findings have pointed out important aspects on their relevance to endothelial function as well as dysfunction of the system which may arise from presence of diseases such as diabetes and hypertension. Diabetes or hypertension-mediated endothelial dysfunction show characteristics such as reduced nitric oxide synthesis through suppression of endothelial nitric oxide synthase activity in endothelial cells, reduced sensitivity of nitric oxide in smooth muscle cells, and inflammation - all of which have been either shown to be directly caused by gene regulatory mechanisms of non-coding RNAs or shown to be having a correlation with them. In this review, we aim to discuss such findings on the role of these non-coding RNAs in diabetes or hypertension-associated endothelial dysfunction and the related mechanisms that may pave the way for alleviating endothelial dysfunction and its related complications such as atherosclerosis.