MicroRNAs Are Involved in End-Organ Damage During Hypertension

Specific microRNAs and heart failure: time for the next step toward application?

A number of microRNAs are involved in the pathophysiological events associated with heart disease. In this review, we discuss miR-21, miR-1, miR-23a, miR-142-5p, miR-126, miR-29, miR-195, and miR-499 because they are most often mentioned as important specific indicators of myocardial hypertrophy and fibrosis leading to heart failure. The clinical use of microRNAs as biomarkers and for therapeutic interventions in cardiovascular diseases appears highly promising. However, there remain many unresolved details regarding their specific actions in distinct pathological phenomena. The introduction of microRNAs into routine practice, as part of the cardiovascular examination panel, will require additional clinically relevant and reliable data. Thus, there remains a need for additional research in this area, as well as the optimization and standardization of laboratory procedures which could significantly shorten the determination time, and make microRNA analysis simpler and more affordable. In this review, we aim to summarize the current knowledge about selected microRNAs related to heart failure, including their potential use in diagnosis, prognosis, and treatment, and options for their laboratory determination.

Roles of Micro Ribonucleic Acids in Astrocytes After Cerebral Stroke

Cerebral stroke is one of the highest-ranking causes of death and the leading cause of disability globally, particularly with an increasing incidence and prevalence in developing countries. Steadily more evidence has indicated that micro ribonucleic acids (miRNAs) have important regulatory functions in gene transcription and translation in the course of cerebral stroke. It is beyond arduous to understand the pathophysiology of cerebral stroke, due in part to the perplexity of influencing the network of the inflammatory response, brain edema, autophagy and neuronal apoptosis. The recent research shows miRNA plays a key role in regulating aquaporin 4 (AQP4), and many essential pathological processes after cerebral stroke. This article reviews the recent knowledge on how miRNA influences the inflammatory response, brain edema, infarction size, and neuronal injury after cerebral stroke. In addition, some miRNAs may serve as potential biomarkers in stroke diagnosis and therapy since the expression of some miRNAs in the blood is stable after cerebral stroke.

miR-29 family: A potential therapeutic target for cardiovascular disease

Cardiovascular disease (CVD), including heart failure, myocardial fibrosis and myocardial infarction, etc, remains one of the leading causes of mortality worldwide. Evidence shows that miRNA plays an important role in the pathogenesis of CVD. miR-29 family is one of miRNA, and over the past decades, many studies have demonstrated that miR-29 is involved in maintaining the integrity of arteries and in the regulation of atherosclerosis, especially in the process of myocardial fibrosis. Besides, heart failure, myocardial fibrosis and myocardial infarction are inseparable from the regulatory role of miR-29. Here, we comprehensively review recent studies regarding miR-29 and CVD, illustrate the possibility of miR-29 as a potential marker for prevention, treatment and prognostic observation.

Circulating microRNAs May Serve as Biomarkers for Hypertensive Emergency End-Organ Injuries and Address Underlying Pathways in an Animal Model

There is an incomplete understanding of the underlying pathophysiology in hypertensive emergencies, where severely elevated blood pressure causes acute end-organ injuries, as opposed to the long-term manifestations of chronic hypertension. Furthermore, current biomarkers are unable to detect early end-organ injuries like hypertensive encephalopathy and renal thrombotic microangiopathy. We hypothesized that circulating microRNAs (c-miRs) could identify acute and chronic complications of severe hypertension, and that combinations of c-miRs could elucidate important pathways involved. We studied the diagnostic accuracy of 145 c-miRs in Dahl salt-sensitive rats fed either a low-salt (N = 20: 0.3% NaCl) or a high-salt (N = 60: 8% NaCl) diet. Subclinical hypertensive encephalopathy and thrombotic microangiopathy were diagnosed by histopathology. In addition, heart failure with preserved ejection fraction was evaluated with echocardiography and N-terminal pro-brain natriuretic peptide; and endothelial dysfunction was studied using acetylcholine-induced aorta ring relaxation. Systolic blood pressure increased severely in animals on a high-salt diet (high-salt 205 ± 20 mm Hg vs. low-salt 152 ± 18 mm Hg, p < 0.001). Partial least squares discriminant analysis revealed 68 c-miRs discriminating between animals with and without hypertensive emergency complications. Twenty-nine c-miRs were strongly associated with hypertensive encephalopathy, 24 c-miRs with thrombotic microangiopathy, 30 c-miRs with heart failure with preserved ejection fraction, and 28 c-miRs with endothelial dysfunction. Hypertensive encephalopathy, thrombotic microangiopathy and heart failure with preserved ejection fraction were associated with deviations in many of the same c-miRs, whereas endothelial dysfunction was associated with a different set of c-miRs. Several of these c-miRs demonstrated fair to good diagnostic accuracy for a composite outcome of hypertensive encephalopathy, thrombotic microangiopathy and heart failure with preserved ejection fraction in receiver-operating-curve analyses (area-under-curve 0.75–0.88). Target prediction revealed an enrichment of genes related to several pathways relevant for cardiovascular disease (e.g., mucin type O-glycan biosynthesis, MAPK, Wnt, Hippo, and TGF-beta signaling). C-miRs could potentially serve as biomarkers of severe hypertensive end-organ injuries and elucidate important pathways involved.

MiR-223-3p in Cardiovascular Diseases: A Biomarker and Potential Therapeutic Target

Cardiovascular diseases, involving vasculopathy, cardiac dysfunction, or circulatory disturbance, have become the major cause of death globally and brought heavy social burdens. The complexity and diversity of the pathogenic factors add difficulties to diagnosis and treatment, as well as lead to poor prognosis of these diseases. MicroRNAs are short non-coding RNAs to modulate gene expression through directly binding to the 3′-untranslated regions of mRNAs of target genes and thereby to downregulate the protein levels post-transcriptionally. The multiple regulatory effects of microRNAs have been investigated extensively in cardiovascular diseases. MiR-223-3p, expressed in multiple cells such as macrophages, platelets, hepatocytes, and cardiomyocytes to modulate their cellular activities through targeting a variety of genes, is involved in the pathological progression of many cardiovascular diseases. It participates in regulation of several crucial signaling pathways such as phosphatidylinositol 3-kinase/protein kinase B, insulin-like growth factor 1, nuclear factor kappa B, mitogen-activated protein kinase, NOD-like receptor family pyrin domain containing 3 inflammasome, and ribosomal protein S6 kinase B1/hypoxia inducible factor 1 α pathways to affect cell proliferation, migration, apoptosis, hypertrophy, and polarization, as well as electrophysiology, resulting in dysfunction of cardiovascular system. Here, in this review, we will discuss the role of miR-223-3p in cardiovascular diseases, involving its verified targets, influenced signaling pathways, and regulation of cell function. In addition, the potential of miR-223-3p as therapeutic target and biomarker for diagnosis and prediction of cardiovascular diseases will be further discussed, providing clues for clinicians.

Molecular Mechanisms, Diagnostic Aspects and Therapeutic Opportunities of Micro Ribonucleic Acids in Atrial Fibrillation

Micro ribonucleic acids (miRNAs) are short non-coding RNA molecules responsible for regulation of gene expression. They are involved in many pathophysiological processes of a wide spectrum of diseases. Recent studies showed their involvement in atrial fibrillation. They seem to become potential screening biomarkers for atrial fibrillation and even treatment targets for this arrhythmia. The aim of this review article was to summarize the latest knowledge about miRNA and their molecular relation to the pathophysiology, diagnosis and treatment of atrial fibrillation.

The diagnostic values of circulating miRNAs for hypertension and bioinformatics analysis

Few studies have compared the performances of those reported miRNAs as biomarkers for hypertension in a same cohort, we aimed to comprehensively examine the performances of those reported miRNAs as biomarkers for hypertension and identify the genes and pathways targetted by these miRNAs. Serum samples were collected from patients hospitalized for hypertension in Zhongshan Hospital. Gene expressions of 25 miRNAs were compared between hypertension and normal groups. Receiver operating characteristic (ROC) curves were used to evaluate the accuracy of those miRNAs as biomarkers for hypertension. miRWALK2.0 and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were performed to predict the target genes and pathways of selected miRNAs. A total of 164 participants were enrolled, amongst which 53 were patients with hypertension, 111 were normal population. MiR-122-5p (area under curve (AUC): 0.750), miR-199a-3p (AUC: 0.744), miR-208a-3p (AUC: 0.743), miR-423-5p (AUC: 0.740), and miR-223-5p (AUC: 0.718) showed better performance than others, and the best performance was the combination of miR-199a-3p, miR-208a-3p, miR-122-5p, and miR-223-3p (AUC: 0.80). Pathway analysis revealed that 94 pathways enriched with genes targetted by miR-199a-3p, miR-208a-3p, miR-122-5p, miR-223-5p. FoxO signaling was enriched with genes targetted by all the three miRNAs (miR-199a-3p, miR-208a-3p, miR-122-5p). The combination of miR-199a-3p, miR-208a-3p, miR-122-5p, and miR-223-3p has a good diagnostic performance for hypertension, and multitudes of possible mechanisms/pathways through which dysregulation of these miRNAs may impact risk of hypertension.

microRNA-21 and hypertension

Hypertension, a multifactorial disease, is a major risk factor for the development of stroke, coronary artery disease, heart failure, and chronic renal failure. However, its underlying cellular and molecular mechanisms remain largely elusive. Numerous studies have shown that microRNAs (miRNAs) are involved in a variety of cellular processes, including cellular proliferation, apoptosis, differentiation, and the development of diseases. microRNA-21 (miR-21), a conserved single-stranded non-coding RNA that is composed of approximately 22 nucleotides, is one of the most intensively studied miRNAs in recent years, and it can regulate gene expression at the post-transcriptional level. miR-21 is expressed in many kinds of tumors and in the cardiovascular system, and it plays an important role in the occurrence and development of cardiovascular diseases. In recent years, more and more evidence indicates that miR-21 plays an important role in hypertension. This article reviews the source, function, and altered levels of miR-21 in hypertension and the role of miR-21 in the pathogenesis of hypertension and target organ damage (TOD). The potential role of miR-21 as a new target for predicting and treating hypertension is also explored.

Reduced brain UCP2 expression mediated by microRNA-503 contributes to increased stroke susceptibility in the high-salt fed stroke-prone spontaneously hypertensive rat

UCP2 maps nearby the lod score peak of STR1-stroke QTL in the SHRSP rat strain. We explored the potential contribution of UCP2 to the high-salt diet (JD)-dependent increased stroke susceptibility of SHRSP. Male SHRSP, SHRSR, two reciprocal SHRSR/SHRSP-STR1/QTL stroke congenic lines received JD for 4 weeks to detect brain UCP2 gene/protein modulation as compared with regular diet (RD). Brains were also analyzed for NF-κB protein expression, oxidative stress level and UCP2-targeted microRNAs expression level. Next, based on knowledge that fenofibrate and Brassica Oleracea (BO) stimulate UCP2 expression through PPARα activation, we monitored stroke occurrence in SHRSP receiving JD plus fenofibrate versus vehicle, JD plus BO juice versus BO juice plus PPARα inhibitor. Brain UCP2 expression was markedly reduced by JD in SHRSP and in the (SHRsr.SHRsp-(D1Rat134-Mt1pa)) congenic line, whereas NF-κB expression and oxidative stress level increased. The opposite phenomenon was observed in the SHRSR and in the (SHRsp.SHRsr-(D1Rat134-Mt1pa)) reciprocal congenic line. Interestingly, the UCP2-targeted rno-microRNA-503 was significantly upregulated in SHRSP and decreased in SHRSR upon JD, with consistent changes in the two reciprocal congenic lines. Both fenofibrate and BO significantly decreased brain microRNA-503 level, upregulated UCP2 expression and protected SHRSP from stroke occurrence. In vitro overexpression of microRNA-503 in endothelial cells suppressed UCP2 expression and led to a significant increase of cell mortality with decreased cell viability. Brain UCP2 downregulation is a determinant of increased stroke predisposition in high-salt-fed SHRSP. In this context, UCP2 can be modulated by both pharmacological and nutraceutical agents. The microRNA-503 significantly contributes to mediate brain UCP2 downregulation in JD-fed SHRSP.

Circulating MicroRNAs in Delayed Cerebral Infarction After Aneurysmal Subarachnoid Hemorrhage

Background

Delayed cerebral infarction (DCI) is a major cause of morbidities after aneurysmal subarachnoid hemorrhage (SAH) and typically starts at day 4 to 7 after initial hemorrhage. MicroRNAs (miRNAs) play an important role in posttranscriptional gene expression control, and distinctive patterns of circulating miRNA changes have been identified for some diseases. We aimed to investigate miRNAs that characterize SAH patients with DCI compared with those without DCI.

Methods and Results

Circulating miRNAs were collected on day 7 after SAH in healthy, SAH‐free controls (n=20), SAH patients with DCI (n=20), and SAH patients without DCI (n=20). We used the LASSO (least absolute shrinkage and selection operator) method of regression analysis to characterize miRNAs associated with SAH patients with DCI compared with those without DCI. In the 28 dysregulated miRNAs associated with DCI and SAH, we found that a combination of 4 miRNAs (miR‐4532, miR‐4463, miR‐1290, and miR‐4793) could differentiate SAH patients with DCI from those without DCI with an area under the curve of 100% (95% CI 1.000–1.000, P<0.001). This 4‐miRNA combination could also distinguish SAH patients with or without DCI from healthy controls with areas under the curve of 99.3% (95% CI 0.977–1.000, P<0.001) and 82.0% (95% CI 0.685–0.955, P<0.001), respectively.

Conclusions

We found a 4‐miRNA combination that characterized SAH patients with DCI. The findings could guide future mechanistic study to develop therapeutic targets.

Circulating progenitor cells in hypertensive subjects: Effectiveness of a treatment with olmesartan in improving cell number and miR profile in addition to expected pharmacological effects

CD34+ circulating progenitor cells (CD34+CPCs) are a population of multipotent cells which can delay the development of atherosclerosis and cardiovascular disease (CVD) in conditions of increased CV risk. MicroRNAs (miRs) 221 and 222 modulate different genes regulating angiogenesis and inflammation; moreover, miR221/22 have beenshown to participate in differentiation and proliferation of CD34+CPCs, inhibiting cell migration and homing. miR221/222 in CD34+CPCs from hypertensive subjects are also increased and associated with CD34+cell number and reactive oxygen species (ROS). We evaluated CD34+CPC number, intracellular miR221/222 and ROS levels, arterial stiffness (AS)and echocardiography indices at baseline (T0).Then, after a six-month treatment with olmesartan, 20 mg/day (T1), in 57 hypertensive patients with left ventricular hypertrophy (LVH) and with no additional risk factor for CVD, and in 29 healthy controls (baseline),fibrinogen, C-reactive protein (CRP), glucose and lipid profiles were also evaluated.At T1, blood pressure values, CRP and fibrinogen levels, ROS and miR221/222 were significantly decreased (all p <0.001), as were AS indices and LV mass index (p<0.001), while cell number was increased (p<0.001). Olmesartan is effective in reducing miR and ROS levels in CD34+CPCs from hypertensive subjects, as well as in increasing CD34+CPC number, providing multilevel CV protection, in addition to its expected pharmacological effects.

Circulating miRNA29 family expression levels in patients with essential hypertension as potential markers for left ventricular hypertrophy

OBJECTIVES

The role of microRNAs (miRs,miRNAs) in the pathogenesis of cardiovascular diseases such as hypertension, as well as their diagnostic potential, has recently attracted much attention. However, target-organ damage (TOD) of hypertension remains a substantial challenge due to the lack of specific biomarkers. The present study was undertaken to identify and validate the potential of circulating miRs as novel biomarkers for TOD.

METHODS

We assessed the expression levels of miR-29a, miR-29b, and miR-29c in 54 patients with untreated essential hypertension and 30 healthy individuals. All patients underwent two-dimensional echocardiography, office, and ambulatory blood pressure monitoring. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was used to evaluate the expression of selected miRs. The expression level of miR-29a, miR-29b, and miR-29c correlations between blood pressure and echocardiography parameters were assessed using the Spearman correlation coefficient.

RESULTS

We observed higher expression levels of miR-29a (31.50 ± 3.90 vs 26.55 ± 1.74; p < 0.001), miR-29b (32.31 ± 2.85vs 27.21 ± 1.59; p < 0.001), and miR-29c (31.13 ± 3.42 vs 25.96 ± 1.88; p < 0.001) in hypertensive patients compared with healthy control individuals. In hypertension patients, 25 patients were left ventricular hypertrophy (LVH), miR-29a (32.82 ± 4.06 vs 30.07 ± 3.68; p = 0.012), miR-29b (33.27 ± 2.84 vs 30.71 ± 3.04; p = 0.02), and miR-29c (32.33 ± 3.52 vs 29.55 ± 3.46; p = 0.005) in LVH patients compared with nLVH patients. We found miR-29a, miR-29b, and miR-29c expression levels showed significant positive correlations with office SBP (p = 0.579, p < 0.001; r = 0.576, p < 0.001; r = 0.598, p < 0.001), office DBP (p = 0.243, p = 0.026; r = 0.304, p = 0.005; r = 0.287, p = 0.008), office PP(r = 0.49, p < 0.001; r = 0.442, p < 0.001; r = 0.479, p < 0.001), 24 h mean SBP(p = 0.511, p < 0.001; r = 0.6, p < 0.001; r = 0.533, p < 0.001), 24 h mean DBP (p = 0. 304, p = 0.005; r = 0.283, p = 0.009; r = 0.340, p = 0.002), and 24 h mean PP (p = 0.385, p < 0.001; r = 0. 506, p < 0.001; r = 0.386, p < 0.001), respectively. The expression levels of miR-29a, miR-29b, and miR-29c were positively related to LVMI (r = 0.65, p < 0.001; r = 0.715, p < 0.001; r = 0.654, p < 0.001), respectively.

CONCLUSION

Circulating the miR-29 family may possibly represent potential non-invasive markers of hypertension and TOD in essential hypertensive patients.

Hypertension and the eye

PURPOSE OF REVIEW

Hypertension is the primary risk factor for cardiovascular disease and mortality that consists a major public health issue worldwide. Hypertension triggers a series of pathophysiological ocular modifications affecting significantly the retinal, choroidal, and optic nerve circulations that result in a range of ocular effects.The retina is the only place in the body where microvasculature can be directly inspected, providing valuable information on hypertension related systemic risks.The aim of this review is to provide an update on latest advances regarding the detection and significance of hypertension related eye signs.

RECENT FINDINGS

It's been shown that measurable retinal microvascular changes may precede progression of systemic microvascular disease.Last years, there are emerging advances in the field retinal imaging and computer software analysis that have enabled the objective and accurate assessment of retinal vascular caliber, while in association with latest epidemiological studies several other retinal vascular features have been recognized, such as vascular length-to-diameter ratio, and wall-to-lumen ratio that may also be associated to hypertension.Additionally, recent genetic studies have provided some insight to vascular pathophysiological processes having correlated new chromosome's loci to hypertensive retinopathy signs.

SUMMARY

Assessment of hypertensive retinopathy signs may convey additional prognostic information on the risk of end-organ damage and may alert for urgent systemic management or even preventive systemic therapies. Further development of retinal vascular imaging and computerized system may provide a significant tool to improve the diagnosis, prognosis, and management of hypertension in clinical practice.

HDL and microRNA therapeutics in cardiovascular disease

microRNAs (miRNA) are small non-coding RNAs (sRNA) that post-transcriptionally regulate gene (mRNA) expression and are implicated in many biological processes and diseases. Many miRNAs have been reported to be altered in cardiovascular disease (CVD); both cellular and extracellular miRNA levels are affected by hypercholesterolemia and atherosclerosis. We and other groups have reported that lipoproteins transport miRNAs in circulation and these lipoprotein signatures are significantly altered in hypercholesterolemia and coronary artery disease (CAD). Extracellular miRNAs are a new class of potential biomarkers for CVD; however, they may also be new drug targets as high-density lipoproteins (HDL) transfer functional miRNAs to recipient cells in an endocrine-like form of intercellular communication that likely suppresses vascular inflammation. Recently, RNA-based drugs have emerged as the next frontier in drug therapy, and there are many miRNA inhibitors and mimics in clinical development. Here, we discuss specific miRNA drug targets and how their manipulation may impact CVD. We also address the potential for manipulating HDL-miRNA levels to treat CVD and the use of HDL as a delivery vehicle for RNA and chemical drugs. Finally, we outline the current and future challenges for HDL and miRNA-based therapeutics for the prevention and treatment of CVD.

Circulating miR155 expression level is positive with blood pressure parameters: Potential markers of target-organ damage

OBJECTIVES

The aim of this study is to evaluate the relationship of miR155 with office and ambulatory blood pressure (BP) parameters and left ventricular hypertrophy (LVH) in patients with hypertension and healthy controls.

METHODS

We assessed the expression level of the miR155 in 50 patients with essential hypertension and 30 healthy individuals. All patients underwent two-dimensional echocardiography, office BP monitoring and ambulatory blood pressure monitoring (ABPM). Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was used to evaluate the expression of selected miR155. The miR155 correlations between BP parameters and left ventricular mass index (LVMI) were assessed using the Spearman correlation coefficient.

RESULTS

We observed higher expression level of miR155 (33.22 ± 2.59 vs. 27.30 ± 1.76; p < 0.001) in hypertensive patients compared with healthy control individuals, as well as in LVH to nLVH group (33.00 ± 2.78 vs. 27.28 ± 1.76; p < 0.001). MiR155 expression level showed significant positive correlations with office measurement of systolic blood pressure (SBP) (r = 0.634, p < 0.001), diastolic blood pressure (DBP) (r = 0.222, p < 0.05), pulse pressure (PP) (r = 0.564, p < 0.001), respectively. And explored miR155 expression level in relation to 24-h ABPM parameters showed significant positive correlation with 24 h mean SBP (r = 0.67, p < 0.001), 24 h mean DBP (r = 0.257, p < 0.05), 24 h mean PP (r = 0.597, p < 0.001), respectively, as well as with LVMI (r = 0.591, p < 0.001).

CONCLUSION

Circulating miR155 may possibly represent potential non-invasive marker of hypertension and target organ damage (TOD) in essential hypertensive patients.

Circulating microRNAs and hypertension--from new insights into blood pressure regulation to biomarkers of cardiovascular risk

Hypertension is a leading cause of cardiovascular morbidity and mortality worldwide, yet the molecular mechanisms underpinning the development of high blood pressure remain incompletely understood. MicroRNAs are small, non-coding RNA molecules approximately 22 nucleotides in length that act as post-transcriptional regulators of gene expression. We highlight, through a review of recent literature, that studies on circulating microRNAs have provided novel insights into blood pressure regulation. They have also complemented tissue-based and animal-based experiments in shedding new light on our understanding of established pathways in hypertension, such as the renin-angiotensin system. Despite a number of challenges, we believe microRNAs herald particular potential in becoming effective biomarkers of target-organ damage in hypertension.

Circulating microRNA 132-3p and 324-3p Profiles in Patients after Acute Aneurysmal Subarachnoid Hemorrhage

Background

Aneurysmal subarachnoid hemorrhage (SAH) is a highly morbid and fatal condition with high rate of cognitive impairment and negative impact in quality of life among survivors. Delayed cerebral infarction (DCI) is one the major factors for these negative outcomes. In this study we compared the circulating microRNA profiles of SAH patients and healthy individuals, and the circulating microRNA profiles of SAH patients with and without DCI.

Methods

Peripheral blood samples on Day 7 after the onset of SAH were subjected to microarray analysis with Affymetrix miRNA 3.0 array and quantitative PCR analysis. SAH patients with (N = 20) and without DCI (N = 20) and Healthy controls (N = 20) were included for analyses.

Results

We demonstrated that 99 miRNAs were found to be dysregulated in the SAH patient group with DCI. 81 miRNAs were upregulated and 18 were downregulated. Findings from KEGG pathway analysis showed that miRNAs and target genes for axon guidance and TGF-beta signaling were involved, implying that the resulted differential miRNA expression pattern reflect the results of SAH instead of etiology of the disease. miR-132-3p and miR-324-3p showed distinctive upregulations in qPCR [miR-132: 9.5 fold (95%CI: 2.3 to 16.7) in DCI group and 3.4 fold (95%CI: 1.0 to 5.8) in Non-DCI group; miR-324: 4924 fold (95%CI: 2620 to 7228) in DCI group and 4545 fold (95%CI: 2408 to 6683) in non-DCI group]. However, there were no significant differences in fold changes between SAH patients with and without DCI [fold change ratios (mean+/-SD): 2.7+/-4.2 and 1.1+/-1.1 for miRNA-132 and miRNA-324].

Conclusion

Our study demonstrated that as compared to healthy control, miR-132 and miR-324 showed a upregulation in both SAH DCI and Non-DCI groups. However, the differences between the SAH DCI and non-DCI groups were not statistically significant.

Modulation of Hypercholesterolemia-Induced Oxidative/Nitrative Stress in the Heart

Hypercholesterolemia is a frequent metabolic disorder associated with increased risk for cardiovascular morbidity and mortality. In addition to its well-known proatherogenic effect, hypercholesterolemia may exert direct effects on the myocardium resulting in contractile dysfunction, aggravated ischemia/reperfusion injury, and diminished stress adaptation. Both preclinical and clinical studies suggested that elevated oxidative and/or nitrative stress plays a key role in cardiac complications induced by hypercholesterolemia. Therefore, modulation of hypercholesterolemia-induced myocardial oxidative/nitrative stress is a feasible approach to prevent or treat deleterious cardiac consequences. In this review, we discuss the effects of various pharmaceuticals, nutraceuticals, some novel potential pharmacological approaches, and physical exercise on hypercholesterolemia-induced oxidative/nitrative stress and subsequent cardiac dysfunction as well as impaired ischemic stress adaptation of the heart in hypercholesterolemia.

MicroRNAs in mesenteric lymph and plasma during acute pancreatitis

OBJECTIVE

To isolate microRNAs (miRNAs) from mesenteric lymph (ML) and peripheral blood and identify those that change with experimental acute pancreatitis (AP). To assess identified AP-associated miRNAs in patient plasma to evaluate them as clinical biomarkers of AP.

BACKGROUND

miRNAs, small non-protein-coding molecules that regulate gene expression, are present in many biological fluids. They are increasingly interesting as biomarkers of disease and as novel signaling molecules in pathogenesis.

METHODS

Affymetrix miRNA profiling was performed on ML collected from 3 groups of rats with either mild or moderate taurocholate-induced AP and sham controls. Quantitative reverse transcription-polymerase chain reaction was used to validate selected miRNAs in matched rat lymph and plasma and then measured in patients with mild or moderate AP and in healthy volunteers.

RESULTS

Eighty-five miRNAs were detectable in rat ML, and many were abundant in all animals irrespective of the presence of AP. Seven miRNAs, comprising miR-375, -217, -148a, -216a, -122, -214, and -138, were increased in ML from rats with AP (P < 0.01). Their abundance also altered with disease severity. miRNAs miR-217, -375, -122, and -148a were also increased in matched rat plasma samples by quantitative reverse transcription-polymerase chain reaction. In the clinical studies, plasma miR-216a was significantly increased in both mild and moderate AP.

CONCLUSIONS

This study is the first to demonstrate both the presence of circulating miRNAs in lymph and the alteration of specific miRNAs in AP. Furthermore, these miRNAs alter in rat and human AP plasma and have potential to be explored as novel biomarkers of pancreatitis.

microRNAs in Cerebrovascular Disease

Cardiovascular diseases are major causes of morbidity and mortality in developed countries. Cerebrovascular diseases, especially stroke, represent major burden of disability and economy impact. Major advances in primary and secondary prevention and therapy are needed in order to tackle this public health problem. Our better understanding of pathophysiology is essential in order to develop novel diagnostic and therapeutic tools and strategies. microRNAs are a family of important post-transcriptional regulators of gene expression and their involvement in the pathophysiology of cerebrovascular diseases has already been reported. Moreover, microRNAs may represent above-mentioned potential diagnostic and therapeutic tools in clinical practice. Within this chapter, we briefly describe basic epidemiology, aetiology and clinical manifestation of following cerebrovascular diseases: extracranial carotid atherosclerosis, acute stroke, intracranial aneurysms and cerebral arterio-venous malformations. Further, in each chapter, the current knowledge about the involvement of specific microRNAs and their potential use in clinical practice will be summarized. More specifically, within the subchapter "miRNAs in carotid atherosclerosis", general information about miRNA involvement in atherosclerosis will be described (miR-126, miR-17-92, miR-155 and others) with special emphasis put on miRNAs affecting carotid plaque progression and stability (e.g. miR-145, miR-146 or miR-217). In the subchapter "miRNAs in acute stroke", we will provide insight into recent knowledge from animal and human studies concerning miRNA profiling in acute stroke and their expression dynamics in brain tissue and extracellular fluids (roles of, e.g. let-7 family, miR-21, miR-29 family, miR-124, miR-145, miR-181 family, miR-210 and miR-223). Subchapters dealing with "miRNAs and AV malformations" and "miRNAs and intracranial aneurysms" will focus on miR-21, miR-26, miR-29 family and miR-143/145.

Non-coding RNAs and hypertension-unveiling unexpected mechanisms of hypertension by the dark matter of the genome

Hypertension is a major risk factor of cardiovascular diseases and a most important health problem in developed countries. Investigations on pathophysiology of hypertension have been based on gene products from coding region that occupies only about 1% of total genome region. On the other hand, non-coding region that occupies almost 99% of human genome has been regarded as "junk" for a long time and went unnoticed until these days. But recently, it turned out that noncoding region is extensively transcribed to non-coding RNAs and has various functions. This review highlights recent updates on the significance of non-coding RNAs such as micro RNAs and long non-coding RNAs (lncRNAs) on the pathogenesis of hypertension, also providing an introduction to basic biology of noncoding RNAs. For example, microRNAs are associated with hypertension via neuro-fumoral factor, sympathetic nerve activity, ion transporters in kidneys, endothelial function, vascular smooth muscle phenotype transformation, or communication between cells. Although reports of lncRNAs on pathogenesis of hypertension are scarce at the moment, new lncRNAs in relation to hypertension are being discovered at a rapid pace owing to novel techniques such as microarray or next-generation sequencing. In the clinical settings, clinical use of non-coding RNAs in identifying cardiovascular risks or developing novel tools for treating hypertension such as molecular decoy or mimicks is promising, although improvement in chemical modification or drug delivery system is necessary.

Characteristics of long non-coding RNAs in the Brown Norway rat and alterations in the Dahl salt-sensitive rat

Long non-coding RNAs (lncRNAs) are potentially important mediators of genomic regulation. lncRNAs, however, remain poorly characterized in the rat model organism widely used in biomedical research. Using poly(A)-independent and strand-specific RNA-seq, we identified 1,500 to 1,800 lncRNAs expressed in each of the following tissues of Brown Norway rats: the renal cortex, renal outer medulla, liver, cardiac left ventricle, adrenal gland, and hypothalamus. Expression and the binding of histone H3K4me3 to promoter regions were confirmed for several lncRNAs. Rat lncRNA expression appeared to be more tissue-specific than mRNA. Rat lncRNAs had 4.5 times fewer exons and 29% shorter transcripts than mRNA. The median cumulative abundance of rat lncRNAs was 53% of that of mRNA. Approximately 28% of the lncRNAs identified in the renal outer medulla appeared to lack a poly(A) tail. Differential expression of 74 lncRNAs was detected in the renal outer medulla between Dahl SS rats, a model of salt-sensitive hypertension, and salt-insensitive, congenic SS.13^BN26 rats fed a high-salt diet. Two of the differentially expressed lncRNAs, which were confirmed, were located within the congenic region and contained several sequence variants. The study identified genome-wide characteristics of lncRNAs in the rat model and suggested a role of lncRNAs in hypertension.

Identification of tubular injury microRNA biomarkers in urine: comparison of next-generation sequencing and qPCR-based profiling platforms

Background

MicroRNAs (miRNAs) are small, non-coding RNAs that regulate protein levels post-transcriptionally. miRNAs play important regulatory roles in many cellular processes and have been implicated in several diseases. Recent studies have reported significant levels of miRNAs in a variety of body fluids, raising the possibility that miRNAs could serve as useful biomarkers. Next-generation sequencing (NGS) is increasingly employed in biomedical investigations. Although concordance between this platform and qRT-PCR based assays has been reported in high quality specimens, information is lacking on comparisons in biofluids especially urine. Here we describe the changes in miRNA expression patterns in a rodent model of renal tubular injury (gentamicin). Our aim is to compare RNA sequencing and qPCR based miRNA profiling in urine specimen from control and rats with confirmed tubular injury.

Results

Our preliminary examination of the concordance between miRNA-seq and qRT-PCR in urine specimen suggests minimal agreement between platforms probably due to the differences in sensitivity. Our results suggest that although miRNA-seq has superior specificity, it may not detect low abundant miRNAs in urine samples. Specifically, miRNA-seq did not detect some sequences which were identified by qRT-PCR. On the other hand, the qRT-PCR analysis was not able to detect the miRNA isoforms, which made up the majority of miRNA changes detected by NGS.

Conclusions

To our knowledge, this is the first time that miRNA profiling platforms including NGS have been compared in urine specimen. miRNAs identified by both platforms, let-7d, miR-203, and miR-320, may potentially serve as promising novel urinary biomarkers for drug induced renal tubular epithelial injury.

High-salt intake suppressed microRNA-133a expression in Dahl SS rat myocardium

Salt-sensitive individuals show earlier and more serious cardiac damage than nonsalt-sensitive ones. Some studies have suggested that microRNA-133a could reduce cardiac hypertrophy and myocardial fibrosis. The current study aims to investigate the different functions of high-salt intake on salt-sensitive (SS) rats and Sprague-Dawley (SD) rats and the involvement of microRNA-133a in these roles. After high-salt intervention, the left ventricular mass (LVW) and left ventricular mass index (LVMI) of the salt-sensitive high salt (SHS) group were obviously higher than those of the salt-sensitive low salt (SLS) group. However, the difference between the Sprague-Dawley high salt (DHS) group and the Sprague-Dawley low salt (DLS) group was not significant. Compared with SLS group, collagen I and connective tissue growth factor (CTGF) in the heart of SHS group were significantly higher, whereas no statistical difference was observed between the DHS group and the DLS group. Compared with low-salt diet, microRNA-133a in the heart of both strains were significantly decreased, but that in the SHS group decreased more significantly. These results suggest that high salt intervention could down-regulate the expression of myocardial microRNA-133a, which may be one of the mechanisms involved in myocardial fibrosis in salt-sensitive hypertension.

MicroRNA-9 and microRNA-126 expression levels in patients with essential hypertension: potential markers of target-organ damage

MicroRNAs (miRs), as essential gene expression regulators, modulate cardiovascular development and disease and thus they are emerging as potential biomarkers and therapeutic targets in cardiovascular disease, including hypertension. We assessed the expression levels of the microRNAs miR-9 and miR-126 in 60 patients with untreated essential hypertension and 29 healthy individuals. All patients underwent two-dimensional echocardiography and 24-hour ambulatory blood pressure monitoring. MicroRNA expression levels in peripheral blood mononuclear cells were quantified by real-time reverse transcription polymerase chain reaction. Hypertensive patients showed significantly lower miR-9 (9.69 ± 1.56 vs 41.08 ± 6.06; P < .001) and miR-126 (3.88 ± 0.47 vs 8.96 ± 1.69; P < .001) expression levels compared with healthy controls. In hypertensive patients, miR-9 expression levels showed a significant positive correlation (r = 0.437; P < .001) with left ventricular mass index. Furthermore, both miR-9 (r = 0.312; P = .015) and miR-126 (r = 0.441; P < .001) expression levels in hypertensive patients showed significant positive correlations with the 24-hour mean pulse pressure. Our data reveal that miR-9 and miR-126 are closely related to essential hypertension in humans, as they show a distinct expression profile in hypertensive patients relative to healthy individuals, and they are associated with clinical prognostic indices of hypertensive target-organ damage in hypertensive patients. Thus, they may possibly represent potential biomarkers and candidate therapeutic targets in essential hypertension.

Differential expression of vascular smooth muscle-modulating microRNAs in human peripheral blood mononuclear cells: novel targets in essential hypertension

Vascular smooth muscle cell (VSMC) phenotypic plasticity has a critical role in the pathophysiology of arterial remodeling in essential hypertension. MicroRNAs are emerging as potential biomarkers and therapeutic targets in cardiovascular disease. We assessed the expression levels of the microRNAs miR-143, miR-145, miR-21, miR-133 and miR-1, which are implicated in VSMC phenotypic modulation, in 60 patients with essential hypertension and 29 healthy individuals. All patients underwent 24-h ambulatory blood pressure (BP) monitoring. MicroRNA levels in peripheral blood mononuclear cells were quantified by real-time reverse transcription polymerase chain reaction. Hypertensive patients showed lower miR-143 (2.20±0.25 versus 4.19±0.57, P<0.001), miR-145 (13.51±1.73 versus 22.38±3.31, P=0.010) and miR-133 (8.15±1.32 versus 37.03±8.18, P<0.001) and higher miR-21 (3.08±0.32 versus 2.06±0.31, P=0.048) and miR-1 (33.94±5.19 versus 12.35±2.13 P=0.006) expression levels compared with controls. In hypertensive patients, we observed correlations of miR-143 (r = -0.380, P=0.003), miR-145 (r=-0.405, P=0.001), miR-21 (r=-0.486, P<0.001) and miR-133 (r=0.479, P<0.001) expression levels with 24-h diastolic BP. Furthermore, we observed correlations of miR-21 (r=-0.291, P=0.024), miR-1 (r=-0.312, P=0.015) and miR-133 (r=0.310, P=0.016) levels with the dipping status. Associations of miR-143 (r=-0.292, P=0.025), miR-145 (r=-0.399, P=0.002), miR-21 (r=-0.343, P=0.008) and miR-133 (r=0.370, P=0.004) levels with 24-h mean pulse pressure were also found. Our data provide important evidence that VSMC-modulating microRNAs are closely related to essential hypertension in humans and they may represent potential therapeutic targets in essential hypertension.

Circulating microRNAs as potential non-invasive biomarkers for the early detection of hypertension-related stroke

Hypertension is one of the most important risk and modifiable factors for stroke. Crucial in managing the cerebrovascular damage caused by long-lasting and inadequately treated hypertension is not only lowering arterial blood pressure but also early predicting subtypes of hypertension-related stroke and applying more effective interventions. Accumulating evidence suggested that circulating microRNAs (miRNAs) could be developed as biomarkers for early recognition of the onset of a variety of diseases. The role of miRNAs has been extensively reviewed, involving cardiac hypertrophy, hypertensive heart failure, kidney failure and renal fibrosis. miRNA research in stroke is still in its infancy, although there are few literatures reviewing the role of miRNAs in the processes of hypertension-related stroke. This review summarizes current advances in miRNAs regulation of critical pathogenic process underlying hypertension, ischemic stroke and hemorrhagic stroke, and highlights the potential of using circulating miRNAs as noninvasive biomarkers for the early detection of hypertension-related stroke.

Hypertension and kidneys: unraveling complex molecular mechanisms underlying hypertensive renal damage

Kidney damage represents a frequent event in the course of hypertension, ranging from a benign to a malignant form of nephropathy depending on several factors, that is, individual susceptibility, degree of hypertension, type of etiology and underlying kidney disease. Multiple mechanisms are involved in determination of kidney glomerular, tubular and interstitial injuries in hypertension. The present review article discusses relevant contributory molecular mechanisms underpinning the promotion of hypertensive renal damage, such as the renin-angiotensin-aldosterone system (RAAS), oxidative stress, endothelial dysfunction, and genetic and epigenetic determinants. We highlighted major pathways involved in the progression of inflammation and fibrosis leading to glomerular sclerosis, tubular atrophy and interstitial fibrosis, thus providing a state of the art review of the pathogenetic background useful for a better understanding of current and future therapeutic strategies toward hypertensive nephropathy. An adequate control of high blood pressure, obtained through an appropriate therapeutic intervention, still represents the key strategy to achieve a satisfactory control of renal damage in hypertension. In this regard, we reviewed the impact of currently available antihypertensive pharmacological treatment on kidney damage, with particular regard to RAAS inhibitors. Notably, recent findings underscored the ability of the kidneys to regenerate and to repair tissue injuries through the differentiation of resident embryonic stem cells. Pharmacological modulation of the renal endogenous reparative process (that is, with angiotensin-converting enzyme inhibitors and AT1 angiotensin II receptor blockers), as well as future therapeutic strategies targeted to the renopoietic system, offers interesting perspectives for the management of hypertensive nephropathy.