Change in circulating microRNA profile of obese children indicates future risk of adult diabetes

High fructose exposure modifies the amount of adipocyte-secreted microRNAs into extracellular vesicles in supernatants and plasma

Background

High fructose exposure induces metabolic and endocrine responses in adipose tissue. Recent evidence suggests that microRNAs in extracellular vesicles are endocrine signals secreted by adipocytes. Fructose exposure on the secretion of microRNA by tissues and cells is poorly studied. Thus, the aim of this study was to evaluate the effect of fructose exposure on the secretion of selected microRNAs in extracellular vesicles from 3T3-L1 cells and plasma from Wistar rats.

Methods

3T3-L1 cells were exposed to 550 µM of fructose or standard media for four days, microRNAs levels were determined in extracellular vesicles of supernatants and cells by RT-qPCR. Wistar rats were exposed to either 20% fructose drink or tap water for eight weeks, microRNAs levels were determined in extracellular vesicles of plasma and adipose tissue by RT-qPCR.

Results

This study showed that fructose exposure increased the total number of extracellular vesicles released by 3T3-L1 cells (p = 0.0001). The levels of miR-143-5p were increased in extracellular vesicles of 3T3-L1 cells exposed to fructose (p = 0.0286), whereas miR-223-3p levels were reduced (p = 0.0286). Moreover, in plasma-derived extracellular vesicles, miR-143-5p was higher in fructose-fed rats (p = 0.001), whereas miR-223-3p (p = 0.022), miR-342-3p (p = 0.0011), miR-140-5p (p = 0.0129) and miR-146b-5p (p = 0.0245) were lower.

Conclusion

Fructose exposure modifies the levels of microRNAs in extracellular vesicles in vitro and in vivo. In particular, fructose exposure increases miR-143-5p, while decreases miR-223-3p and miR-342-3p.

Focus on MicroRNAs as Biomarker in Pediatric Diseases

BACKGROUND

MiRNAs are a class of small non-coding RNAs that are involved in the post-transcriptional regulation of gene expression. MiRNAs are considered a class of epigenetic biomarkers. These biomarkers can investigate disease at different stages: diagnosis, therapy or clinical follow-up.

OBJECTIVE

The aim of this paper is to highlight the innovative use of miRNAs in several childhood diseases.

METHODS

We conducted a literature review to search the usage of miRNAs in pediatric clinical routine or experimental trials.

RESULTS

We found a possible key role of miRNAs in different pediatric illnesses (metabolic alterations, coagulation defects, cancer).

CONCLUSION

The modest literature production denotes that further investigation is needed to assess and validate the promising role of miRNAs as non-invasive biomarkers in pediatric disorders.

Adipocyte, Immune Cells, and miRNA Crosstalk: A Novel Regulator of Metabolic Dysfunction and Obesity

Obesity is characterized as a complex and multifactorial excess accretion of adipose tissue (AT) accompanied with alterations in the immune response that affects virtually all age and socioeconomic groups around the globe. The abnormal accumulation of AT leads to several metabolic diseases, including nonalcoholic fatty liver disorder (NAFLD), low-grade inflammation, type 2 diabetes mellitus (T2DM), cardiovascular disorders (CVDs), and cancer. AT is an endocrine organ composed of adipocytes and immune cells, including B-Cells, T-cells and macrophages. These immune cells secrete various cytokines and chemokines and crosstalk with adipokines to maintain metabolic homeostasis and low-grade chronic inflammation. A novel form of adipokines, microRNA (miRs), is expressed in many developing peripheral tissues, including ATs, T-cells, and macrophages, and modulates the immune response. miRs are essential for insulin resistance, maintaining the tumor microenvironment, and obesity-associated inflammation (OAI). The abnormal regulation of AT, T-cells, and macrophage miRs may change the function of different organs including the pancreas, heart, liver, and skeletal muscle. Since obesity and inflammation are closely associated, the dysregulated expression of miRs in inflammatory adipocytes, T-cells, and macrophages suggest the importance of miRs in OAI. Therefore, in this review article, we have elaborated the role of miRs as epigenetic regulators affecting adipocyte differentiation, immune response, AT browning, adipogenesis, lipid metabolism, insulin resistance (IR), glucose homeostasis, obesity, and metabolic disorders. Further, we will discuss a set of altered miRs as novel biomarkers for metabolic disease progression and therapeutic targets for obesity.

Parallel Multi-Omics in High-Risk Subjects for the Identification of Integrated Biomarker Signatures of Type 1 Diabetes

BACKGROUND

Biomarkers are crucial for detecting early type-1 diabetes (T1D) and preventing significant β-cell loss before the onset of clinical symptoms. Here, we present proof-of-concept studies to demonstrate the potential for identifying integrated biomarker signature(s) of T1D using parallel multi-omics.

METHODS

Blood from human subjects at high risk for T1D (and healthy controls; n = 4 + 4) was subjected to parallel unlabeled proteomics, metabolomics, lipidomics, and transcriptomics. The integrated dataset was analyzed using Ingenuity Pathway Analysis (IPA) software for disturbances in the at-risk subjects compared to controls.

RESULTS

The final quadra-omics dataset contained 2292 proteins, 328 miRNAs, 75 metabolites, and 41 lipids that were detected in all samples without exception. Disease/function enrichment analyses consistently indicated increased activation, proliferation, and migration of CD4 T-lymphocytes and macrophages. Integrated molecular network predictions highlighted central involvement and activation of NF-κB, TGF-β, VEGF, arachidonic acid, and arginase, and inhibition of miRNA Let-7a-5p. IPA-predicted candidate biomarkers were used to construct a putative integrated signature containing several miRNAs and metabolite/lipid features in the at-risk subjects.

CONCLUSIONS

Preliminary parallel quadra-omics provided a comprehensive picture of disturbances in high-risk T1D subjects and highlighted the potential for identifying associated integrated biomarker signatures. With further development and validation in larger cohorts, parallel multi-omics could ultimately facilitate the classification of T1D progressors from non-progressors.

The expression profile and role of non-coding RNAs in obesity

Latest years have experienced a dramatic upsurge in the knowledge about the function of non-coding transcripts in the determination of diverse human phenotypes including obesity. Several miRNAs and lncRNAs participate in the regulation of metabolic pathways leading to obesity. Several lncRNAs such as Mist, lincIRS2, lncRNA-p5549, H19, GAS5 and SNHG9 have been shown to be down-regulated in adipose tissues or other biological samples in the obese human or animal subjects. On the other hand, Meg3, Plnc1, Blnc1, AC092834.1, TINCR and PVT1 are among up-regulated lncRNAs in the obese subjects. Tens of miRNAs have differential expression between obese and non-obese subjects or between mature adipocytes and pre-adipocytes. Understanding the molecular mechanism of involvement of non-coding RNAs in the pathobiology of obesity would simplify design of therapeutic choices for protecting against obesity and its related comorbidities. We explain the available literature on the function of these transcripts in the pathobiology of obesity.

Comprehensive Analysis Reveals Novel Interactions between Circulating MicroRNAs and Gut Microbiota Composition in Human Obesity

Background: The determinants that mediate the interactions between microRNAs and the gut microbiome impacting on obesity are scarcely understood. Thus, the aim of this study was to investigate possible interactions between circulating microRNAs and gut microbiota composition in obesity. Method: The sample comprised 78 subjects with obesity (cases, body mass index (BMI): 30–40 kg/m²) and 25 eutrophic individuals (controls, BMI ≤ 25 kg/m²). The expression of 96 microRNAs was investigated in plasma of all individuals using miRCURY LNA miRNA Custom PCR Panels. Bacterial DNA sequencing was performed following the Illumina 16S protocol. The FDR correction was used for multiple comparison analyses. Results: A total of 26 circulating microRNAs and 12 bacterial species were found differentially expressed between cases and controls. Interestingly, an interaction among three miRNAs (miR-130b-3p, miR-185-5p and miR-21-5p) with Bacteroides eggerthi and BMI levels was evidenced (r² = 0.148, p = 0.004). Moreover, these microRNAs regulate genes that participate in metabolism-related pathways, including fatty acid degradation, insulin signaling and glycerolipid metabolism. Conclusions: This study characterized an interaction between the abundance of 4 bacterial species and 14 circulating microRNAs in relation to obesity. Moreover, the current study also suggests that miRNAs may serve as a communication mechanism between the gut microbiome and human hosts.

Change in modifiable maternal characteristics and behaviours between consecutive pregnancies and offspring adiposity: A systematic review

Causal evidence links modifiable maternal exposures during the periconceptional period with offspring obesity. The interconception period may be an important time to intervene. We systematically identified studies examining change in modifiable maternal exposures between pregnancies and offspring adiposity. We searched for longitudinal studies published between 1990 and 2019, which included measurements taken on at least two occasions in the period from 1 year prior to the conception of the first birth to the time of the second birth, and which included a measure of adiposity in second, or higher order, siblings. Age, ethnicity and genetics were not considered modifiable; all other factors including length of the interpregnancy interval were. Eleven studies satisfied the inclusion criteria. Higher interpregnancy weight gain or loss, maternal smoking inception, mothers smoking in their first pregnancy and quitting, increasing the number of cigarettes smoked and longer interpregnancy intervals were positively associated with adiposity in second or higher order children. Vaginal birth after caesarean delivery was protective. Further research is needed to ascertain whether the risk of adiposity is fixed based on first pregnancy exposures or if interpregnancy change alters the risk for a subsequent child. This can inform the type and effectiveness of interventions for mothers prior to a subsequent pregnancy.

Exosomal Secretion of Adipose Tissue during Various Physiological States

Exosomes are secreted extracellular vesicles containing a wide array of biologically active components. Recent studies have demonstrated that exosomes serve as an important vehicle for extracellular communication and exert systemic effects on the physiology of organisms. Adipose tissues (ATs) play a key role in balancing systemic energy homeostasis as a central hub for fatty acid metabolism. At the same time, proper endocrine function of ATs has also been shown to be crucial for regulating physiological and metabolic health. The endocrine function of ATs is partially mediated by AT-derived exosomes that regulate metabolic homeostasis, such as insulin signaling, lipolysis, and inflammation. During the pathogenesis of obesity, metabolic syndrome, and cancer, exosomes shed by the resident cells in ATs may also have a role in regulating the progression of these diseases along with associated pathologies. In this review, we summarize the contents of AT-derived exosomes and their effects on various cell populations along with possible underlying molecular mechanisms. We further discuss the potential applications of exosomes as a drug delivery tool and therapeutic target.

Association between circulating microRNAs 486, 146b and 15b and serum betatrophin levels in obese; type 2 diabetic and non-diabetic children

BACKGROUND

This study tested the association between serum levels of microRNA-486, -146b and -15b and betatrophin in normal and obese children with/without type 2 diabetes mellitus (T2DM).

METHODS

the study included 120 children; divided into three groups: G1 (50 healthy), G2 (35 obese) and G3 (35 obese with T2DM). The levels of microRNA-486, 146b and 15b and serum betatrophin were measured by their corresponding methods.

RESULTS

serum microRNA-486, -146b, -15b and betatrophin levels were significantly high in G3 followed by G2 then G1 (p = 0.002, > 0.001, > 0.001, and > 0.001, respectively). Especially in G3, these levels correlated positively with the BMI percentile (r = 0.44, 0.58, 0.38, and 0.46, p = 0.007, > 0.001, 0.021, and 0.005, respectively), serum glucose (r = 0.56, 0.49, 0.82, 0.60, and 0.42, p > 0.001, 0.003, > 0.001, and > 0.001, respectively) and HbA1c% (r = 0.56, 0.39, 0.66, and 0.42, p > 0.001, 0.019, > 0.001, and 0.032, respectively) while, showed negative correlations with correlated with serum insulin levels (r = - 0.37, - 0.42, - 0.58, and - 0.41, p = 0.021, 0.012, > 0.001 and 0.013, respectively) and with serum C-peptide levels (r = - 0.76, - 0.50, - 0.35 and - 0.42, p > 0.001, 0.002, 0.036 and 0.011, respectively). Serum betatrophin levels correlated positively with microRNA-486, -146b and -15b levels in G2 (r = 0.35, 0.80, and 0.67, p = 0.036, > 0.001, and,> 0.001, respectively), and in G3 (r = 0.57, 0.36, and 0.38, p > 0.001, 0.029 and, 0.023, respectively).

CONCLUSIONS

Circulating microRNA-486, 146b and 15b increase significantly in obese children with T2DM and these levels correlate positively with serum betatrophin levels. Further studies are required to test the role of targeting of these microRNAs and betatrophin in the timely management of obesity and/or T2DM in children.

MicroRNAs and obesity-induced endothelial dysfunction: key paradigms in molecular therapy

The endothelium plays a pivotal role in maintaining vascular health. Obesity is a global epidemic that has seen dramatic increases in both adult and pediatric populations. Obesity perturbs the integrity of normal endothelium, leading to endothelial dysfunction which predisposes the patient to cardiovascular diseases. MicroRNAs (miRNAs) are short, single-stranded, non-coding RNA molecules that play important roles in a variety of cellular processes such as differentiation, proliferation, apoptosis, and stress response; their alteration contributes to the development of many pathologies including obesity. Mediators of obesity-induced endothelial dysfunction include altered endothelial nitric oxide synthase (eNOS), Sirtuin 1 (SIRT1), oxidative stress, autophagy machinery and endoplasmic reticulum (ER) stress. All of these factors have been shown to be either directly or indirectly caused by gene regulatory mechanisms of miRNAs. In this review, we aim to provide a comprehensive description of the therapeutic potential of miRNAs to treat obesity-induced endothelial dysfunction. This may lead to the identification of new targets for interventions that may prevent or delay the development of obesity-related cardiovascular disease.

Potential Roles of Adipocyte Extracellular Vesicle-Derived miRNAs in Obesity-Mediated Insulin Resistance

Recently, extracellular microRNAs (miRNAs) from adipose tissue have been shown to be involved in the development of insulin resistance. Here, we summarize several mechanisms explaining the pathogenesis of obesity-induced insulin resistance and associated changes in the expression of obesity-associated extracellular miRNAs. We discuss how miRNAs, particularly miR-27a, miR-34a, miR-141-3p, miR-155, miR210, and miR-222, in extracellular vesicles secreted from the adipose tissue can affect the insulin signaling pathway in metabolic tissue. Understanding the role of these miRNAs will further support the development of therapeutics for obesity and metabolic disorders such as type 2 diabetes.

Circulating miR-216a as a biomarker of metabolic alterations and obesity in women

Obesity leads to an amplified risk of disease and contributes to the occurrence of type 2 diabetes, fatty liver disease, coronary heart disease, stroke, chronic kidney disease and various types of cancer. MicroRNAs (miRNAs), small non-coding RNA molecules of 20-25 nucleotides, can remain stable in plasma and have been studied as potential (predictive) biomarkers for obesity and related metabolic disorders. The aim of this study was to identify circulating miRNAs as biomarkers for obesity status and metabolic alterations in women. Circulating miR-216a and miR-155-5p were selected by miRNA expression profiling and validated by real time quantitative PCR in a validation cohort of 60 obese women and 60 normal weight-age-matched control women. This was supplemented by correlation analysis of the candidate miRNA and anthropometric variables, blood biochemistry and lipid profile markers. Circulating miR-216a was validated as a biomarker of obesity status with significantly reduced levels in obese women. Interestingly, this was associated with a negative correlation between the plasma miR-216a content and body mass index (BMI), waist circumference, mean arterial pressure (MAP), triglycerides, ratio of total cholesterol/high density lipoprotein (HDL)-cholesterol and high sensitivity-C reactive protein (hs-CRP).Taken together, we provide evidence for an abnormally expressed circulating miRNA, miR-216a, with additive value as a predictive marker for obesity that correlates with metabolic alterations presented by lipid profile and inflammatory markers.

Crosstalk between circulating microRNAs and chronotypical features in subjects with metabolic syndrome

Circulating microRNAs (miRNAs) are valuable biomarkers that may provide important insight into the pathogenesis of metabolic syndrome (MetS). Moreover, there is an association between chronotypical characteristics and MetS predisposition. Considering that expression of some miRNAs is circadian-rhythm-dependent, the aim of this study was to investigate the circulating miRNA profile in subjects with and without MetS in association with chronotype. The expression of 86 metabolic syndrome-related miRNAs was investigated in the plasma of 21 subjects with MetS and in 82 subjects without MetS using miRCURY LNA miRNA PCR System technology. Chronotype was assessed using the Horne and Östberg Morningness-Eveningness Questionnaire. Bioinformatic analyses were performed to explore the target genes and biological pathways regulated by the selected miRNAs. Subjects with MetS were more often evening chronotype compared to non-MetS controls. Additionally, four miRNAs (miR-140-3p, miR-150-5p, miR-375, and miR-29 c-3p) demonstrated interaction with MetS and chronotype. Interestingly, the target genes of these four miRNAs participate in pathways related to the circadian clock. In conclusion, we identified four circulating miRNAs whose circulating levels could interact with MetS and chronotype.

Insulin delivery with a needle-free insulin injector versus a conventional insulin pen in Chinese patients with type 2 diabetes mellitus: A 16-week, multicenter, randomized clinical trial (the FREE study)

BACKGROUND

Insulin therapy is poorly accepted by patients with type 2 diabetes mellitus (T2DM). A needle-free insulin injector has been developed for patients who fear injections or are reluctant to initiate insulin therapy when it is clearly indicated. The objective of this trial was to evaluate the glucose-lowering effect, tolerability, patient satisfaction and compliance with insulin treatment via a needle-free insulin injector (NFII) compared with insulin treatment via a conventional insulin pen (CIP) in patients with T2DM.

METHODS

A total of 427 patients with T2DM were enrolled in a prospective, multicenter, randomized, open-label study, and were randomly assigned 1:1 to receive 16 weeks' treatment with basal insulin or premixed insulin administered either by a NFII or CIP.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT03243903).

FINDINGS

In the 412 patients who completed the study, the adjusted mean reduction of HbA1c from baseline at week 16 in the NFII group was 0.55% (95% CI -0.71, -0.39), which was non-inferior and statistically superior to the HbA1c reduction in the CIP group (0.26%, 95% CI -0.42, -0.11). Patients in the NFII group showed significantly higher treatment satisfaction scores than those in the CIP group (mean scores, 8.17 ± 1.78 vs. 7.21 ± 2.22, respectively; p<0.0001). The occurrence of hypoglycemia was similar in the two groups, and the NFII group showed reduced incidences of skin scratches, indurations and lower VAS pain scores.

INTERPRETATION

Insulin therapy through needle-free injector showed a non-inferior glycemic-lowering effect and a significantly enhanced level of patient satisfaction with insulin treatment compared with conventional insulin therapy through needle injections. In addition, the needle-free injector also had a better safety profile.

FUNDING

This study were funded by Beijing QS Medical Technology Co., Ltd, as well as The Major Chronic Non-communicable Disease Prevention and Control Research.

Circulating microRNAs overexpressed in macrosomia: an experimental and bioinformatic approach

Low birth weight (LBW) and macrosomia have been associated with later-in-life metabolic alterations. The aim of this study was to elucidate whether the expression levels of circulating microRNAs (c-miRNAs) associated with adult metabolic diseases are also dysregulated in newborns with LBW or macrosomia. The expression levels of five microRNAs (miRNAs) associated with metabolic diseases were quantified in dried blood spots of newborns with adequate birth weight, LBW and macrosomia by stem-loop real-time polymerase chain reaction. miR-29a-5p, miR-126-3p, miR-221-3p, and miR-486-5p were significantly overexpressed in newborns with macrosomia and showed no significant change in the LBW group compared to normal weight controls. miR-320a showed no statistical difference among groups. We predicted the putative target genes and pathways of the overexpressed miRNAs with bioinformatic tools. Bioinformatic analyses of overexpressed miRNAs predicted target genes involved in carbohydrate metabolism, participate in FoxO and PI3K/Akt signaling pathways, and are associated with diabetes, obesity, and cardiovascular diseases. The overexpression of circulating miR-29a-5p, miR-126-3p, miR-221-3p, and miR-486-5p may explain the increased risk of obesity and diabetes associated with macrosomia. The use of dried blood spots from newborn screening cards to quantify miRNAs expression levels could be an early and minimally invasive predictive tool for these metabolic alterations.

A prospective case-control study on miRNA circulating levels in subjects born small for gestational age (SGA) evaluated from childhood into young adulthood

OBJECTIVE

microRNAs (miRNAs) associated with metabolic risk have never been extensively investigated in SGA subjects. The aim of the current study was to evaluate miRNAs in SGA and AGA subjects and their relationships with the metabolic status and growth.

DESIGN AND METHODS

A prospective longitudinal case-control study was performed in 23 SGA with postnatal catch-up growth and 27 AGA subjects evaluated at the age of 9 and 21 years. Circulating levels of miR-122-5p, miR-16-5p, miR-126-3p, and miR-486-5p were assessed by qPCR.

RESULTS

SGA subjects were shorter both at 9 and at 21 years. No significant differences in insulin like growth factors and metabolic profile were found with the exception of basal glycemia at 9 years. miRNA levels did not differ between SGA and AGA subjects, at 9 and 21 years. miR-16-5p and miR-126-3p levels were higher at 9 than at 21 years. In SGA subjects, miR-122-5p at 9 years was inversely related to adiponectin levels at 21 years and miR-486-5p at 9 years was inversely related to whole-body insulin sensitivity at 9 years and directly related to Hb1Ac at 21 years. Regression analyses showed no predictive value of miRNAs for growth parameters in neither SGA nor AGA subjects.

CONCLUSIONS

SGA with postnatal catch-up growth did not show any difference in metabolic risk markers or miRNA circulating levels compared to AGA controls in childhood and young adulthood. miR-122-5p during childhood could identify SGA subjects at higher risk of developing insulin resistance and, eventually, type 2 diabetes in adulthood but further studies are needed to confirm it.

MiRNAs as Novel Adipokines: Obesity-Related Circulating MiRNAs Influence Chemosensitivity in Cancer Patients

Adipose tissue is an endocrine organ, capable of regulating distant physiological processes in other tissues via the release of adipokines into the bloodstream. Recently, circulating adipose-derived microRNAs (miRNAs) have been proposed as a novel class of adipokine, due to their capacity to regulate gene expression in tissues other than fat. Circulating levels of adipokines are known to be altered in obese individuals compared with typical weight individuals and are linked to poorer health outcomes. For example, obese individuals are known to be more prone to the development of some cancers, and less likely to achieve event-free survival following chemotherapy. The purpose of this review was twofold; first to identify circulating miRNAs which are reproducibly altered in obesity, and secondly to identify mechanisms by which these obesity-linked miRNAs might influence the sensitivity of tumors to treatment. We identified 8 candidate circulating miRNAs with altered levels in obese individuals (6 increased, 2 decreased). A second literature review was then performed to investigate if these candidates might have a role in mediating resistance to cancer treatment. All of the circulating miRNAs identified were capable of mediating responses to cancer treatment at the cellular level, and so this review provides novel insights which can be used by future studies which aim to improve obese patient outcomes.

Circulating adiposity-related microRNAs as predictors of the response to a low-fat diet in subjects with obesity

Recent studies have revealed the critical role of several microRNAs (miRNAs) in energy homeostasis and metabolic processes and suggest that circulating miRNAs can be used as early predictors of weight loss in the design of precision nutrition. Thus, the aim of this study was to investigate circulating adiposity‐related miRNAs as biomarkers of the response to two specific weight loss dietary treatments. The expression of 86 miRNAs was investigated in plasma of 78 subjects with obesity randomized to two different diets [moderately high‐protein diet (n = 38) and low‐fat diet (n = 40)] and in 25 eutrophic controls (BMI ≤ 25 kg/m²). Bioinformatic analyses were performed to explore the target genes and biological pathways regulated by the dysregulated miRNAs. As results, 26 miRNAs were found differently expressed in eutrophic and volunteers with obesity. Moreover, 7 miRNAs (miR‐130a‐3p, miR‐142‐5p, miR‐144‐5p, miR‐15a‐5p, miR‐22‐3p, miR‐221‐3p and miR‐29c‐3p) were differentially expressed between responders and non‐responders to a low‐fat diet. Furthermore, after adjustment for basal glucose levels, 1‐SD increase in miR‐22‐3p expression was associated with reduction in the risk of non‐response to low‐fat diet [OR = 0.181, 95% CI (0.084‐0.947), P = .043]. Bioinformatic analyses evidenced that these 7 miRNAs regulate the expression of genes participating in important metabolic pathways. Conclusively, 7 circulating miRNAs related to adiposity could be used for predicting the response to a low‐fat diet intervention prescribed to lose weight.

The clinical potential of circulating microRNAs in obesity

Obesity is a complex condition that is characterized by excessive fat accumulation, which can lead to the development of metabolic disorders, such as type 2 diabetes mellitus, nonalcoholic fatty liver disease and cardiovascular diseases. Evidence is accumulating that circulating microRNAs (miRNAs) act as a new class of endocrine factor. These miRNAs are released by many types of tissue, including adipose tissues. miRNAs might serve as endocrine and paracrine messengers that facilitate communication between donor cells and tissues with receptor cells or target tissues, thereby potentially having important roles in metabolic organ crosstalk. Moreover, many miRNAs are closely associated with the differentiation of adipocytes and are dysregulated in obesity. As such, circulating miRNAs are attractive potential biomarkers and hold promise for the development of miRNA-based therapeutics (such as miRNA mimetics, anti-miRNA oligonucleotides and exosomes loaded with miRNA) for obesity and related disorders. Here we review the latest research progress on the roles of circulating miRNAs in metabolic organ crosstalk. In addition, we discuss the clinical potential of circulating miRNAs as feasible biomarkers for the assessment of future risk of metabolic disorders and as therapeutic targets in obesity and related diseases.

MicroRNA Signatures as Future Biomarkers for Diagnosis of Diabetes States

Diabetes results from the inability of pancreatic islets to maintain blood glucose concentrations within a normal physiological range. Clinical features are usually not observed until islets begin to fail and irreversible damage has occurred. Diabetes is generally diagnosed based on elevated glucose, which does not distinguish between type 1 and 2 diabetes. Thus, new diagnostic approaches are needed to detect different modes of diabetes before manifestation of disease. During prediabetes (pre-DM), islets undergo stress and release micro (mi) RNAs. Here, we review studies that have measured and tracked miRNAs in the blood for those with recent-onset or longstanding type 1 diabetes, obesity, pre-diabetes, type 2 diabetes, and gestational diabetes. We summarize the findings on miRNA signatures with the potential to stage progression of different modes of diabetes. Advances in identifying selective biomarker signatures may aid in early detection and classification of diabetic conditions and treatments to prevent and reverse diabetes.

Circulating miRNAs as Biomarkers of Obesity and Obesity-Associated Comorbidities in Children and Adolescents: A Systematic Review

Early detection of obesity and its associated comorbidities in children needs priority for the development of effective therapeutic intervention. Circulating miRNAs (microRNAs) have been proposed as biomarkers for obesity and its comorbidities; therefore, we conducted a systematic review to summarize results of studies that have quantified the profile of miRNAs in children and adolescents with obesity and/or associated disorders. Nine studies aiming to examine differences in miRNA expression levels between children with normal weight and obesity or between obese children with or without cardiometabolic diseases were included in this review. We identified four miRNAs overexpressed in obesity (miR-222, miR-142-3, miR-140-5p, and miR-143) and two miRNAs (miR-122 and miR-34a) overexpressed in children with obesity and nonalcoholic fatty liver disease (NAFLD) and/or insulin resistance. In conclusion, circulating miRNAs are promising diagnostic biomarkers of obesity-associated diseases such as NAFLD and type 2 diabetes already in childhood. However, more studies in children, using massive search technology and with larger sample sizes, are required to draw any firm conclusions.

Downregulation of miR-320 Alleviates Endoplasmic Reticulum Stress and Inflammatory Response in 3T3-L1 Adipocytes

OBJECTIVE

MicroRNAs serve important roles in the regulation of endoplasmic reticulum stress (ERs). This study aimed to investigate the role of microRNA-320 (miR-320) in the development of ERs and the inflammatory response in 3T3-L1 adipocytes.

MATERIALS AND METHODS

The adipose tissue expression levels of miR-320 and ERs markers (GRP78, GRP94, Derlin-1 and CHOP) and the serum concentration of inflammatory cytokines (TNF-α, NF-κB and IL-6) in obese patients were evaluated using quantitative real-time RT-PCR or enzyme-linked immunosorbent assay. The correlation of miR-320 with genes involved in ERs and inflammation was analyzed. The effects of miR-320 on ERs and inflammation were explored using mature 3T3-L1 adipocytes, which were pretreated with palmitic acid (PA).

RESULTS

ERs markers and inflammatory cytokines were all upregulated in obese patients. Adipose tissue miR-320 expression was also increased in obese patients, and had positive correlations with the levels of ERs markers and inflammatory cytokines. After PA treatment, the levels of ERs markers and inflammatory cytokines were elevated significantly in 3T3-L1 adipocytes. Moreover, miR-320 expression was increased in the cells under ERs status. The upregulation of miR-320 could enhance the expression of ERs markers and inflammatory cytokines, but the downregulation of miR-320 resulted in the opposite results.

CONCLUSION

The data of this study indicate that miR-320 expression is upregulated in ERs status, and the downregulation of miR-320 ameliorates ERs and the inflammatory response in 3T3-L1 adipocytes. We consider that the approaches to decrease miR-320 expression may be novel therapeutic strategies for the treatment of obesity and obesity-related diseases.

The Pathogenic Role of Dysregulated Epigenetic Modifications in Autoimmune Diseases

Autoimmune diseases can be chronic with relapse of inflammatory symptoms, but it can be also acute and life-threatening if immune cells destroy life-supporting organs, such as lupus nephritis. The etiopathogenesis of autoimmune diseases has been revealed as that genetics and environmental factors-mediated dysregulated immune responses contribute to the initiation and development of autoimmune disorders. However, the current understanding of pathogenesis is limited and the underlying mechanism has not been well defined, which lows the development of novel biomarkers and new therapeutic strategies for autoimmune diseases. To improve this, broadening and deepening our understanding of pathogenesis is an unmet need. As genetic susceptibility cannot explain the low accordance rate of incidence in homozygous twins, epigenetic regulations might be an additional explanation. Therefore, this review will summarize current progress of studies on epigenetic dysregulations contributing to autoimmune diseases, including SLE, rheumatoid arthritis (RA), psoriasis, type 1 diabetes (T1D), and systemic sclerosis (SSc), hopefully providing opinions on orientation of future research, as well as discussing the clinical utilization of potential biomarkers and therapeutic strategies for these diseases.

Associations between body condition score at parturition and microRNA profile in colostrum of dairy cows as evaluated by paired mapping programs

MicroRNA (miRNA) are abundant in milk, and likely have regulatory activity involving lactation and immunity. The objective of this study was to determine the miRNA profile in colostrum of overconditioned cows compared with cows of more moderate body condition score (BCS) at calving. Multiparous cows with either high (≥4.0 on a scale of 1 to 5; n = 7) or moderate BCS (2.75 to 3.50; n = 9) in the week before parturition were selected from a commercial dairy herd. Blood and colostrum were sampled within 24 h after calving. Blood serum was analyzed for free fatty acid (FFA) concentration. MicroRNA was isolated from colostrum samples after removing milk fat and cells. MicroRNA were sequenced, and reads were mapped to the bovine genome and to the existing database of miRNA at miRBase.org. Two programs, Oasis 2.0 and miRDeep2, were employed in parallel for read alignment, and analysis of miRNA count data was performed using DESeq2. Identification of differentially expressed miRNA from DESeq2 was not affected by the differences in miRNA detected by the 2 mapping programs. Most abundant miRNA included miR-30a, miR-148a, miR-181a, let-7f, miR-26a, miR-21, miR-22, and miR-92a. Large-scale shifts in miRNA profile were not observed; however, colostrum of cows with high BCS contained less miR-486, which has been linked with altered glucose metabolism. Colostrum from cows with elevated serum FFA contained less miR-885, which may be connected to hepatic function during the transition period. Potential functions of abundant miRNA suggest involvement in development and maintenance of cellular function in the mammary gland, with the additional possibility of influencing neonatal tissue and immune system development.

The Profiling and Role of miRNAs in Diabetes Mellitus

Diabetes mellitus (DM), a complex metabolic disease, has become a global threat to human health worldwide. Over the past decades, an enormous amount of effort has been devoted to understand how microRNAs (miRNAs), a class of small non-coding RNA regulators of gene expression at the post-transcriptional level, are implicated in DM pathology. Growing evidence suggests that the expression signature of a specific set of miRNAs has been altered in the progression of DM. In the present review, we summarize the recent investigations on the miRNA profiles as novel DM biomarkers in clinical studies and in animal models, and highlight recent discoveries on the complex regulatory effect and functional role of miRNAs in DM.

Post-transcriptional markers associated with clinical complications in Type 1 and Type 2 diabetes mellitus

The delayed diagnosis and the inadequate treatment of diabetes increase the risk of chronic complications. The study of regulatory molecules such as miRNAs can provide expression profiles of diabetes and diabetes complications. We evaluated the mononuclear cell miRNA profiles of 63 Type 1 and Type 2 diabetes patients presenting or not microvascular complications, and 40 healthy controls, using massive parallel sequencing. Gene targets, enriched pathways, dendograms and miRNA-mRNA networks were performed for the differentially expressed miRNAs. Six more relevant miRNAs were validated by RT-qPCR and data mining analysis. MiRNAs associated with specific complications included: i) neuropathy (miR-873-5p, miR-125a-5p, miR-145-3p and miR-99b-5p); ii) nephropathy (miR-1249-3p, miR-193a-5p, miR-409-5p, miR-1271-5p, miR-501-3p, miR-148b-3p and miR-9-5p); and iii) retinopathy (miR-143-3p, miR-1271-5p, miR-409-5p and miR-199a-5p). These miRNAs mainly targeted gene families and specific genes associated with advanced glycation end products and their receptors. Sets of miRNAs were also defined as potential targets for diabetes/diabetes complication pathogenesis.

Circulating microRNAs in human obesity: a systematic review

Context: Differential expression profiles of microRNAs have been reported in human obesity suggesting a miRNAs role in the development of obesity and associated disorders. Objective: To review circulating microRNAs (c-miRNAs) dysregulated in human obesity and to predict their possible target genes. Methods: We performed a systematic review on PubMed database (PROSPERO, CRD42017077742) for original works on c-miRNAs and human obesity and recorded c-miRNAs with differential expression profiles. Potential target genes and metabolic pathways for dysregulated miRNAs with at least two independent reports were searched using bioinformatic tools. Results: Twenty-two c-miRNAs are overexpressed, nine underexpressed and two c-miRNAs dysregulated in both directions in people with obesity compared to lean controls. Bioinformatic analyses suggest these c-miRNAs target on genes associated with fatty acid metabolism and PI3k/Akt pathway. Conclusion: Literature records 33 c-miRNAs confirmedly dysregulated in human obesity. Their predicted target genes are involved in pathways that could explain the development of obesity and its comorbidities. Further research will clarify the role of these miRNAs on metabolic diseases and their usefulness for the prognosis, prevention and treatment of obesity.

Plasma microRNA Profiling Reveals Novel Biomarkers of Epicardial Adipose Tissue: A Multidetector Computed Tomography Study

Epicardial adipose tissue (EAT) constitutes a novel parameter for cardiometabolic risk assessment and a target for therapy. Here, we evaluated for the first time the plasma microRNA (miRNA) profile as a source of biomarkers for epicardial fat volume (EFV). miRNAs were profiled in plasma samples from 180 patients whose EFV was quantified using multidetector computed tomography. In the screening study, 54 deregulated miRNAs were identified in patients with high EFV levels (highest tertile) compared with matched patients with low EFV levels (lowest tertile). After filtering, 12 miRNAs were selected for subsequent validation. In the validation study, miR-15b-3p, miR-22-3p, miR-148a-3p miR-148b-3p and miR-590-5p were directly associated with EFV, even after adjustment for confounding factors (p value < 0.05 for all models). The addition of miRNA combinations to a model based on clinical variables improved the discrimination (area under the receiver-operating-characteristic curve (AUC) from 0.721 to 0.787). miRNAs correctly reclassified a significant proportion of patients with an integrated discrimination improvement (IDI) index of 0.101 and a net reclassification improvement (NRI) index of 0.650. Decision tree models used miRNA combinations to improve their classification accuracy. These results were reproduced using two proposed clinical cutoffs for epicardial fat burden. Internal validation corroborated the robustness of the models. In conclusion, plasma miRNAs constitute novel biomarkers of epicardial fat burden.

Epigenetic modifications induced by exercise: Drug-free intervention to improve cognitive deficits associated with obesity

Obesity and metabolic disorders are increasing worldwide and are associated with brain atrophy and dysfunction, which are risk factors for late-onset dementia and Alzheimer's disease. Epidemiological studies demonstrated that changes in lifestyle, including the frequent practice of physical exercise are able to prevent and treat not only obesity/metabolic disorders, but also to improve cognitive function and dementia. Several biochemical pathways and epigenetic mechanisms have been proposed to understand the beneficial effects of physical exercise on cognition. This manuscript revised central ongoing research on epigenetic mechanisms induced by exercise and the beneficial effects on obesity-associated cognitive decline, highlighting potential mechanistic mediators.

Obesity and dyslipidemia

Obesity, a pandemic of the modern world, is intimately associated with dyslipidemia, which is mainly driven by the effects of insulin resistance and pro-inflammatory adipokines. However, recent evidence suggests that obesity-induced dyslipidemia is not a unique pathophysiological entity, but rather has distinct characteristics depending on many individual factors. In line with that, in a subgroup of metabolically healthy obese (MHO) individuals, dyslipidemia is less prominent or even absent. In this review, we will address the main characteristics of dyslipidemia and mechanisms that induce its development in obesity. The fields, which should be further investigated to expand our knowledge on obesity-related dyslipidemia and potentially yield new strategies for prevention and management of cardiometabolic risk, will be highlighted. Also, we will discuss recent findings on novel lipid biomarkers in obesity, in particular proprotein convertase subtilisin/kexin type 9 (PCSK9), as the key molecule that regulates metabolism of low-density lipoproteins (LDL), and sphingosine-1-phosphate (S1P), as one of the most important mediators of high-density lipoprotein (HDL) particles function. Special attention will be given to microRNAs and their potential use as biomarkers of obesity-associated dyslipidemia.

Circulating microRNAs are associated with early childhood obesity: results of the I.Family Study

Background

Nearly 10 years ago, the World Health Organization reported the increasing prevalence of overweight and obesity worldwide as a challenge for public health due to the associated adverse consequences. Epidemiological studies established a firm relationship between an elevated body mass index and chronic conditions such as diabetes, dyslipidemia, hypertension, heart disease, non-alcoholic fatty liver disease, and some types of cancer. Omic studies demonstrated that microRNA (miRNA) profile changes in tissues correlate with a number of diseases, including obesity. Recent studies showed a remarkable stability of miRNAs also in blood, emphasizing their potential as theranostic agents for a variety of disorders and conditions. A number of miRNAs enriched in homeostasis of obesity and metabolic disorders have been characterized in previous researches.

Aim

This work was finalized to investigate the differential circulating miRNAs signature in early childhood obesity. Our cross-sectional study analyzed the signature of circulating miRNAs in plasma samples of normal weight (n = 159) and overweight/obese (n = 149) children and adolescents participating to the I.Family study, an EC-funded study finalized to investigate the etiology of overweight, obesity and related disorders and the determinants of food choice, lifestyle, and related health outcomes in children and adolescents of eight European countries (www.ifamilystudy.eu).

Results

Differences in miRNA signature with respect to anthropometric and biochemical variables were analyzed. A high degree of variability in levels of circulating miRNAs was identified among children from different countries, in line with recent reports supporting the hypothesis that these molecules are likewise affected by environmental and lifestyle factors. A panel of miRNAs differentially expressed in overweight/low-grade obesity children was characterized (miR-551a and miR-501-5p resulted upregulated; miR-10b-5p, miR-191-3p, miR-215-5p, and miR-874-3p resulted downregulated). ROC curves were also constructed for experimentally confirmed miRNAs. Single miRNAs generally exhibited low AUC values with the highest values for miR-874-3p and miR-501-5p which in combination provided an interesting value (AUC = 0.782). Pearson’s analysis confirmed that miR-10b-5p, miR-215-5p, miR-501-5p, miR-551a, and miR-874-3p significantly correlated with BMI z-score. Molecular interactions of obesity-associated miRNAs were also predicted by bioinformatics tools.

Conclusions

Our work showed that several circulating miRNAs are differentially represented in overweight/low-grade obesity children and adolescents. Although causal pathways cannot be firmly inferred, it is conceivable that circulating miRNAs may be new biomarkers of early childhood obesity.

Trial registration

ISRCTN, ISRCTN62310987. Registered 23/02/2018 - Retrospectively registered.

Electronic supplementary material

The online version of this article (10.1186/s12263-018-0622-6) contains supplementary material, which is available to authorized users.

Potential role of circulating microRNAs (486-5p, 497, 509-5p and 605) in metabolic syndrome Egyptian male patients

Objective: This study aims to evaluate the expression pattern of circulating microRNAs (miR)-486-5p, miR-497, miR-509-5p, and miR-605 in the serum of metabolic syndrome (MetS) Egyptian male patients. Methods: In this study, the circulating miR-486-5p, miR-497, miR509-5p, and miR-605 were amplified and quantitatively detected by quantitative real-time polymerase chain reaction in sera of 55 MetS male patients in comparison to 20 male controls. The level of fasting plasma glucose and triacylglycerol (TAG) were measured using calorimetric assay. Blood pressure was measured using mercuric sphygmomanometer. Anthropometric measurements were done to each individual. Furthermore, MetS patients were defined according to the criteria proposed by the American Heart Association and divided into three groups according to MetS index. Results: The study was performed on three groups and a control group defined as follows: group 1: 15 MetS patients who fulfilled all diagnostic criteria of MetS; group 2: 20 MetS patients with normal blood pressure; group 3: 20 MetS patients with normal TAG levels.The levels of miRs are expressed as [median (IQR)]. miR-486-5-p and miR-497 expression were elevated in group 1 [31.9(49), p˂0.0001; 73.1(42.5), p˂0.0001], group 2 [36.4(15.7), p˂0.0001; 68.3(54.8), p˂0.0001], and group (3) [10.8(18.9), p=0.0014; 27.5(39.7), p=0.0012]. MiR-509-5p was elevated in groups 1 and 2 [501(468), p=0.0001], [309(436), p=0.0006], respectively, while normally expressed in group 3 [0.93(0.077), p=0.0001]. miR-605 was elevated in groups 1 and 3 [25.4(20.0), p=0.0018], [54.8(65.8), p˂0.0001], while normally expressed in group 2 [0.84(0.67), p˂0.0001]. Conclusion: miRs (486-5p, 497, 509-5p, and 605) serum levels were higher in MetS patients than in healthy control subjects; therefore, these serum miRs can serve as early biomarkers and can be used to follow-up the prognosis of MetS.

Obesity in Type 1 Diabetes: Pathophysiology, Clinical Impact, and Mechanisms

There has been an alarming increase in the prevalence of obesity in people with type 1 diabetes in recent years. Although obesity has long been recognized as a major risk factor for the development of type 2 diabetes and a catalyst for complications, much less is known about the role of obesity in the initiation and pathogenesis of type 1 diabetes. Emerging evidence suggests that obesity contributes to insulin resistance, dyslipidemia, and cardiometabolic complications in type 1 diabetes. Unique therapeutic strategies may be required to address these comorbidities within the context of intensive insulin therapy, which promotes weight gain. There is an urgent need for clinical guidelines for the prevention and management of obesity in type 1 diabetes. The development of these recommendations will require a transdisciplinary research strategy addressing metabolism, molecular mechanisms, lifestyle, neuropsychology, and novel therapeutics. In this review, the prevalence, clinical impact, energy balance physiology, and potential mechanisms of obesity in type 1 diabetes are described, with a special focus on the substantial gaps in knowledge in this field. Our goal is to provide a framework for the evidence base needed to develop type 1 diabetes-specific weight management recommendations that account for the competing outcomes of glycemic control and weight management.

Circulating microRNAs and adipokines as markers of metabolic syndrome in adolescents with obesity

BACKGROUND

Circulating microRNAs (miRNAs) as valuable biomarkers yielded important insights into the pathogenesis of obesity.

AIM

This study aimed to describe the circulating miRNA profile for adolescences and its association with the circulating levels leptin and adiponectin according to specific degree of obesity.

METHODS

RT-PCR and immunoassy analysis were used to study circulating miRNA profile, adipokines; adiponectin (A), leptin (L), and L/A ratio as well as other factors of metabolic syndrome (MS) in 250 adolescents with severe obesity.

RESULTS

In morbidly obese adolescents, we identified at least 10 circulating miRNAs, including increased concentrations of miRNAS; miR-142-3p, miR-140-5p, miR-222 miR-143, miR-130, and decreased concentrations of miR-532-5p, miR-423-5p, miR-520c-3p, miR-146a, and miR-15a, which were strongly linked to measures of BMI, WHtR, adipokines; adiponectin, leptin, L/A ratio, and other MS related biomarkers such as FBS, insulin, HOMA-IR, C-peptide, and circulated plasma lipids such as TG, HDL-C, and LDL-C.

CONCLUSION

Circulating miRNAs showed significant association with plasma levels of adipokines; adiponectin, leptin, and L/A ratios in adolescents with severe obesity. The study provides that regulation of miRNAs expression is associated with adipokines, and other related MS metabolic factors. Thus, early detection of any changes in circulating miRNAs profiles may play a promising role in identifying obese children or adolescents who may suffer from severe metabolic syndrome.

Nighttime light exposure enhances Rev-erbα-targeting microRNAs and contributes to hepatic steatosis

OBJECTIVE

The exposure to artificial light at night (ALAN) disrupts the biological rhythms and has been associated with the development of metabolic syndrome. MicroRNAs (miRNAs) display a critical role in fine-tuning the circadian system and energy metabolism. In this study, we aimed to assess whether altered miRNAs expression in the liver underlies metabolic disorders caused by disrupted biological rhythms.

RESULTS

We found that C3H/HePas mice exposed to ALAN developed obesity, and hepatic steatosis, which was paralleled by decreased expression of Rev-erbα and up-regulation of its lipogenic targets ACL and FAS in liver. Furthermore, the expression of Rev-erbα-targeting miRNAs, miR-140-5p, 185-5p, 326-5p and 328-5p were increased in this group. Consistently, overexpression of these miRNAs in primary hepatocytes reduced Rev-erbα expression at the mRNA and protein levels. Importantly, overexpression of Rev-erbα-targeting miRNAs increased mRNA levels of Acly and Fasn.

CONCLUSION

Thus, altered miRNAs profile is an important mechanism underlying the disruption of the peripheral clock caused by exposure to ALAN, which could lead to hepatic steatosis.

Improved systemic metabolism and adipocyte biology in miR-150 knockout mice

INTRODUCTION

Short non-coding micro-RNAs (miRNAs) are post-transcriptional factors that directly regulate protein expression by degrading or inhibiting target mRNAs; however, the role of miRNAs in obesity and cardiometabolic disease remains unclarified. Based on our earlier study demonstrating that miR-150 influences lipid metabolism, we have studied effects of miR-150 on systemic metabolism and adipocyte biology.

MATERIALS AND METHODS

Metabolic phenotypes including body weight, food intake, body composition, glucose tolerance and insulin sensitivity were assessed in WT and global miR-150 KO male mice fed a high-fat diet. Molecular changes in epididymal adipose tissue were evaluated through qRT-PCR and Western blotting.

RESULTS

miR-150 KO mice displayed lower body weight characterized by a reduction in % fat mass while % lean mass was increased. Lower body weight was associated with reduced food consumption and an increase in circulating leptin concentrations, as well as enhanced insulin sensitivity and glucose tolerance compared with WT mice. Absence of miR-150 resulted in increased mTOR expression known to participate in increased leptin production leading to reduction of food intake. Expression of PGC-1α, another target gene of miR-150, was also increased together with upregulation of PPARα and glycerol kinase in adipose tissue as well as other genes participating in triglyceride degradation and lipid oxidation.

CONCLUSION

miR-150 KO mice showed metabolic benefits accompanied by reduced body weight, decreased energy intake, and enhanced lipid metabolism. miR-150 may represent both a biomarker and novel therapeutic target regarding obesity and insulin resistance.

Epigenetics as biomarkers in autoimmune diseases

Autoimmune diseases are immune system disorders in which immune cells cannot distinguish self-antigens from foreign ones. The current criteria for autoimmune disease diagnosis are based on clinical manifestations and laboratory tests. However, none of these markers shows both high sensitivity and specificity. In addition, some autoimmune diseases, for example, systemic lupus erythematosus (SLE), are highly heterogeneous and often exhibit various manifestations. On the other hand, certain autoimmune diseases, such as Sjogren's syndrome versus SLE, share similar symptoms and autoantibodies, which also causes difficulties in diagnosis. Therefore, biomarkers that have both high sensitivity and high specificity for diagnosis, reflect disease activity and predict drug response are necessary. An increasing number of publications have proposed the abnormal epigenetic modifications as biomarkers of autoimmune diseases. Therefore, this review will comprehensively summarize the epigenetic progress in the pathogenesis of autoimmune disorders and unearth potential biomarkers that might be appropriate for disease diagnosis and prediction.

Circulating MicroRNA Profile as a Potential Predictive Biomarker for Early Diagnosis of Spontaneous Abortion in Patients With Subclinical Hypothyroidism

An increasing number of studies suggest that subclinical hypothyroidism (SCH) is associated with complications of gestation, including spontaneous abortion (SA). However, the underlying mechanism is not clear. MicroRNA (miRNA) has been demonstrated to be closely related to gynecological reproductive diseases. We determined miRNA expression in patients with SCH, SCH with SA (SCH + SA), and in those with SA as well as healthy controls (HCs), and analyzed whether dysregulation in several miRNAs was specific to these cohorts. An Agilent Human miRNA array was used to explore miRNA levels in pooled serum samples as a pilot study, followed by a validation of selected miRNAs by real-time polymerase chain reaction in SCH (N = 24), SA (N = 19), SCH + SA (N = 21), and HC cohorts (N = 18). The relative expression of miR-940 was elevated in the SCH + SA group compared with SCH, SA, and HC groups. In addition, miR-486-5p was upregulated in the SCH + SA group compared with SA and HC groups, without a difference noted between SCH + SA and SCH groups. Further analysis suggested that miR-940 or miR-486-5p may be potential predictive biomarkers for the early diagnosis of SA in patients with SCH.