The shear-responsive transcription factor Kruppel-like factor 2 (KLF2) is a critical regulator of endothelial gene expression patterns induced by atheroprotective flow. As microRNAs (miRNAs) post-transcriptionally control gene expression in many pathogenic and physiological processes, we investigated the regulation of miRNAs by KLF2 in endothelial cells. KLF2 binds to the promoter and induces a significant upregulation of the miR-143/145 cluster. Interestingly, miR-143/145 has been shown to control smooth muscle cell (SMC) phenotypes; therefore, we investigated the possibility of transport of these miRNAs between endothelial cells and SMCs. Indeed, extracellular vesicles secreted by KLF2-transduced or shear-stress-stimulated HUVECs are enriched in miR-143/145 and control target gene expression in co-cultured SMCs. Extracellular vesicles derived from KLF2-expressing endothelial cells also reduced atherosclerotic lesion formation in the aorta of ApoE(-/-) mice. Combined, our results show that atheroprotective stimuli induce communication between endothelial cells and SMCs through an miRNA- and extracellular-vesicle-mediated mechanism and that this may comprise a promising strategy to combat atherosclerosis.

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Atheroprotective communication between endothelial cells and smooth muscle cells through miRNAs.

Rationale:MicroRNAs are small RNAs that control gene expression. Besides their cell intrinsic function, recent studies reported that microRNAs are released by cultured cells and can be detected in the blood. Objective:To address the regulation of circulating microRNAs in patients with stable coronary artery disease. Methods and Results:To determine the regulation of microRNAs, we performed a microRNA profile using RNA isolated from n=8 healthy volunteers and n=8 patients with stable coronary artery disease that received state-of-the-art pharmacological treatment. Interestingly, most of the highly expressed microRNAs that were lower in the blood of patients with coronary artery disease are known to be expressed in endothelial cells (eg, miR-126 and members of the miR-17∼92 cluster). To prospectively confirm these data, we detected selected microRNAs in plasma of 36 patients with coronary artery disease and 17 healthy volunteers by quantitative PCR. Consistent with the data obtained by the profile, circulat...

Circulating MicroRNAs in Patients With Coronary Artery Disease

First recognized as regulators of development in worms and fruitflies, microRNAs are emerging as pivotal modulators of mammalian cardiovascular development and disease. Individual microRNAs modulate the expression of collections of messenger RNA targets that often have related functions, thereby governing complex biological processes. The wideranging functions of microRNAs in the cardiovascular system have provided new perspectives on disease mechanisms and have revealed intriguing therapeutic targets, as well as diagnostics, for a variety of cardiovascular disorders.

/pdf/pervasive-roles-of-micrornas-in-cardiovascular-biology-vkshynhhvn.pdf

Pervasive roles of microRNAs in cardiovascular biology

MicroRNAs (miRNAs) are a class of posttranscriptional regulators that have recently introduced an additional level of intricacy to our understanding of gene regulation. There are currently over 10,000 miRNAs that have been identified in a range of species including metazoa, mycetozoa, viridiplantae, and viruses, of which 940, to date, are found in humans. It is estimated that more than 60% of human protein-coding genes harbor miRNA target sites in their 3′ untranslated region and, thus, are potentially regulated by these molecules in health and disease. This review will first briefly describe the discovery, structure, and mode of function of miRNAs in mammalian cells, before elaborating on their roles and significance during development and pathogenesis in the various mammalian organs, while attempting to reconcile their functions with our existing knowledge of their targets. Finally, we will summarize some of the advances made in utilizing miRNAs in therapeutics.

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MicroRNAs in development and disease.

Podosomes and invadopodia are actin-based dynamic protrusions of the plasma membrane of metazoan cells that represent sites of attachment to - and degradation of - the extracellular matrix. The key proteins in these structures include the actin regulators cortactin and neural Wiskott-Aldrich syndrome protein (N-WASP), the adaptor proteins Tyr kinase substrate with four SH3 domains (TKS4) and Tyr kinase substrate with five SH3 domains (TKS5), and the metalloprotease membrane type 1 matrix metalloprotease (MT1MMP; also known as MMP14). Many cell types can produce these structures, including invasive cancer cells, vascular smooth muscle and endothelial cells, and immune cells such as macrophages and dendritic cells. Recently, progress has been made in our understanding of the regulatory and functional aspects of podosome and invadopodium biology and their role in human disease.

/pdf/the-ins-and-outs-of-podosomes-and-invadopodia-148ffcdbx6.pdf

The 'ins' and 'outs' of podosomes and invadopodia: characteristics, formation and function.

Mechanisms controlling vascular smooth muscle cell (VSMC) plasticity and renewal still remain to be elucidated completely. A class of small RNAs called microRNAs (miRs) regulate gene expression at the post-transcriptional level. Here, we show a critical role of the miR-143/145 cluster in SMC differentiation and vascular pathogenesis, also through the generation of a mouse model of miR-143 and -145 knockout (KO). We determined that the expression of miR-143 and -145 is decreased in acute and chronic vascular stress (transverse aortic constriction and in aortas of the ApoE KO mouse). In human aortic aneurysms, the expression of miR-143 and -145 was significantly decreased compared with control aortas. In addition, overexpression of miR-143 and -145 decreased neointimal formation in a rat model of acute vascular injury. An in-depth analysis of the miR-143/145 KO mouse model showed that this miR cluster is expressed mostly in the SMC compartment, both during development and postnatally, in vessels and SMC-containing organs. Loss of miR-143 and miR-145 expression induces structural modifications of the aorta, because of an incomplete differentiation of VSMCs. In conclusion, our results show that the miR-143/145 gene cluster has a critical role during SMC differentiation and strongly suggest its involvement in the reversion of the VSMC differentiation phenotype that occurs during vascular disease.

/pdf/the-knockout-of-mir-143-and-145-alters-smooth-muscle-cell-1p2idujqw1.pdf

The knockout of miR-143 and -145 alters smooth muscle cell maintenance and vascular homeostasis in mice: correlates with human disease

Postbariatric hypoglycemia (PBH) is an increasingly recognized late metabolic complication of bariatric surgery, characterized by low blood glucose levels 1–3 h after a meal, particularly if the meal contains rapid-acting carbohydrates. PBH can often be effectively managed through appropriate nutritional measures, which remain the cornerstone treatment today. However, their implementation in daily life continues to challenge both patients and health care providers. Emerging digital technologies may allow for more informed and improved decision-making through better access to relevant data to manage glucose levels in PBH. Examples include applications for automated food analysis from meal images, digital receipts of purchased food items or integrated platforms allowing the connection of continuously measured glucose with food and other health-related data. The resulting multi-dimensional data can be processed with artificial intelligence systems to develop prediction algorithms and decision support systems with the aim of improving glucose control, safety, and quality of life of PBH patients. Digital innovations, however, face trade-offs between user burden vs. amount and quality of data. Further challenges to their development are regulatory non-compliance regarding data ownership of the platforms acquiring the required data, as well as user privacy concerns and compliance with regulatory requirements. Through navigating these trade-offs, digital solutions could significantly contribute to improving the management of PBH.

/pdf/digital-solutions-to-diagnose-and-manage-postbariatric-1xyhl03w.pdf

Digital Solutions to Diagnose and Manage Postbariatric Hypoglycemia

Bariatric surgery increases postprandial glucose excursions with higher peaks and lower nadirs. Etiologically linked is the phenomenon of postbariatric hypoglycaemia (PBH), an increasingly recognized metabolic disorder. Continuous glucose monitoring (CGM) has become an important tool in the diagnosis and management of PBH. The Ambulatory Glucose Profile (AGP) is an internationally recognized and standardized format that provides structured and graphical compilation of CGM data to guide treatment decisions in people with diabetes. However, its applicability to patients suffering from bariatric surgery-induced dysglycaemia, such as PBH, remains limited. Based on the collection of CGM data in healthy individuals and post-bariatric surgery patients with and without PBH, we selected a set of summary statistics that are important to diagnose the condition, decide on and evaluate the efficacy of therapeutic strategies. We propose a novel AGPr which contains the following: %time spent with non-physiological glucose values, the diurnal distribution of hypoglycaemic events (including level and duration) and information on postprandial glucose excursions by colour-coding of rate of glucose change and variability metrics. The new AGPr uses data generated by CGM to provide a rapid visual presentation of glucose dynamics and hypoglycemia burden in post-bariatric surgery individuals.
 
 
 
 L.Cossu: None. G.Cappon: Consultant; Dexcom, Inc. D.Herzig: None. A.Facchinetti: None. L.Bally: Research Support; Dexcom, Inc., Ypsomed AG.
 
 
 
 University of Padova, Italy (SID-Networking Project 2021)


1020-P: A New Ambulatory Glucose Profile Report to Evaluate and Support Glucose Control in People after Bariatric Surgery

Aims To investigate the effect of empagliflozin on glucose dynamics in individuals suffering from postbariatric hypoglycaemia (PBH) after Roux-en-Y gastric bypass (RYGB). Methods Twenty-two adults with PBH after RYGB were randomized to empagliflozin 25 mg or placebo once daily over 20 days in a randomized, double-blind, placebo-controlled, crossover trial. The primary efficacy outcome was the amplitude of plasma glucose excursion (peak to nadir) during a mixed meal tolerance test (MMTT). Outcomes of the outpatient period were assessed using continuous glucose monitoring (CGM) and an event-tracking app. Results The amplitude of glucose excursion during the MMTT was 8.1±2.4 mmol/L with empagliflozin vs 8.1±2.6 mmol/L with placebo (mean±SD, p=0.807). CGM-based mean amplitude of glucose excursion (MAGE) during the 20 day-period was lower with empagliflozin than placebo (4.8±1.3 vs 5.2±1.6. p=0.028). Empagliflozin reduced the time spent with CGM values >10.0 mmol/L (3.8±3.5 % vs. 4.7±3.8 %, p =0.009), but not the time spent with CGM values <3.0 mmol/L (1.7±1.6 % vs. 1.5±1.5 %, p=0.457). No significant difference was observed in the quantity and quality of recorded symptoms. Eleven adverse events occurred with empagliflozin (three drug-related) and six with placebo. Conclusions Empagliflozin 25 mg reduces glucose excursions but not hypoglycaemia in individuals with PBH.

Randomized, double-blind, placebo-controlled crossover trial of once daily empagliflozin 25 mg for the treatment of postprandial hypoglycaemia after Roux-en-Y gastric bypass.

Luca Cossu

Papers

The knockout of miR-143 and -145 alters smooth muscle cell maintenance and vascular homeostasis in mice: correlates with human disease

Digital Solutions to Diagnose and Manage Postbariatric Hypoglycemia

1020-P: A New Ambulatory Glucose Profile Report to Evaluate and Support Glucose Control in People after Bariatric Surgery

Randomized, double-blind, placebo-controlled crossover trial of once daily empagliflozin 25 mg for the treatment of postprandial hypoglycaemia after Roux-en-Y gastric bypass.