Routine Pressure Wire Assessment Versus Conventional Angiography in the Management of Patients With Coronary Artery Disease: The RIPCORD 2 Trial.

BACKGROUND: Measurement of fractional flow reserve (FFR) has an established role in guiding percutaneous coronary intervention. We tested the hypothesis that, at the stage of diagnostic invasive coronary angiography, systematic FFR-guided assessment of coronary artery disease would be superior, in terms of resource use and quality of life, to assessment by angiography alone. METHODS: We performed an open-label, randomized, controlled trial in 17 UK centers, recruiting 1100 patients undergoing invasive coronary angiography for the investigation of stable angina or non-ST-segment-elevation myocardial infarction. Patients were randomized to either angiography alone (angiography) or angiography with systematic pressure wire assessment of all epicardial vessels >2.25 mm in diameter (angiography+FFR). The coprimary outcomes assessed at 1 year were National Health Service hospital costs and quality of life. Prespecified secondary outcomes included clinical events. RESULTS: In the angiography+FFR arm, the median number of vessels examined was 4 (interquartile range, 3-5). The median hospital costs were similar: angiography, £4136 (interquartile range, £2613-£7015); and angiography+FFR, £4510 (£2721-£7415; P=0.137). There was no difference in median quality of life using the visual analog scale of the EuroQol EQ-5D-5L: angiography, 75 (interquartile range, 60-87); and angiography+FFR, 75 (interquartile range, 60-90; P=0.88). The number of clinical events was as follows: deaths, 5 versus 8; strokes, 3 versus 4; myocardial infarctions, 23 versus 22; and unplanned revascularizations, 26 versus 33, with a composite hierarchical event rate of 8.7% (48 of 552) for angiography versus 9.5% (52 of 548) for angiography+FFR (P=0.64). CONCLUSIONS: A strategy of systematic FFR assessment compared with angiography alone did not result in a significant reduction in cost or improvement in quality of life. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT01070771.

Randomized, Placebo-Controlled Phase 2b Study to Evaluate the Safety and Efficacy of Recombinant Human Lecithin Cholesterol Acyltransferase in Acute ST-Segment-Elevation Myocardial Infarction: Results of REAL-TIMI 63B.

BACKGROUND: High-density lipoprotein plays a key role in reverse cholesterol transport. In addition, high-density lipoprotein particles may be cardioprotective and reduce infarct size in the setting of myocardial injury. Lecithin-cholesterol acyltransferase is a rate-limiting enzyme in reverse cholesterol transport. MEDI6012 is a recombinant human lecithin-cholesterol acyltransferase that increases high-density lipoprotein cholesterol. Administration of lecithin-cholesterol acyltransferase has the potential to reduce infarct size and regress coronary plaque in acute ST-segment-elevation myocardial infarction. METHODS: REAL-TIMI 63B (A Randomized, Placebo­controlled Phase 2b Study to Evaluate the Safety and Efficacy of MEDI6012 in Acute ST Elevation Myocardial Infarction) was a phase 2B multinational, placebo-controlled, randomized trial. Patients with ST-segment-elevation myocardial infarction within 6 hours of symptom onset and planned for percutaneous intervention were randomly assigned 2:1 to MEDI6012 (2- or 6-dose regimen) or placebo and followed for 12 weeks. The primary outcome was infarct size as a percentage of left ventricular mass by cardiac MRI at 10 to 12 weeks, with the primary analysis in patients with TIMI Flow Grade 0 to 1 before percutaneous intervention who received at least 2 doses of MEDI6012. The secondary outcome was change in noncalcified plaque volume on coronary computed tomographic angiography from baseline to 10 to 12 weeks with the primary analysis in patients who received all 6 doses of MEDI6012. RESULTS: A total of 593 patients were randomly assigned. Patients were a median of 62 years old, 77.9% male, and 95.8% statin naive. Median time from symptom onset to randomization was 146 (interquartile range [IQR], 103-221) minutes and from hospitalization to randomization was 12.7 (IQR, 6.6-24.0) minutes, and the first dose of drug was administered a median of 8 (IQR, 3-13) minutes before percutaneous intervention. The index myocardial infarction was anterior in 69.6% and TIMI Flow Grade 0 to 1 in 65.1% of patients. At 12 weeks, infarct size did not differ between treatment groups (MEDI6012: 9.71%, IQR 4.79-16.38; placebo: 10.48%, [IQR, 4.92-16.61], 1-sided P=0.79. There was also no difference in noncalcified plaque volume (geometric mean ratio, 0.96 [95% CI, NA-1.10], 1-sided P=0.30). There was no significant difference in treatment emergent serious adverse events. CONCLUSIONS: Administration of MEDI6012 in patients with acute ST-segment-elevation myocardial infarction did not result in a significant reduction in infarct size or noncalcified plaque volume at 12 weeks. MEDI6012 was well tolerated with no excess in overall serious adverse events. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT03578809.

Novel Paracrine Action of Endothelium Enhances Glucose Uptake in Muscle and Fat.

[Figure: see text].

Endothelial IGF-1 receptor mediates crosstalk with the gut wall to regulate microbiota in obesity.

Changes in composition of the intestinal microbiota are linked to the development of obesity and can lead to endothelial cell (EC) dysfunction. It is unknown whether EC can directly influence the microbiota. Insulin-like growth factor-1 (IGF-1) and its receptor (IGF-1R) are critical for coupling nutritional status and cellular growth; IGF-1R is expressed in multiple cell types including EC. The role of ECIGF-1R in the response to nutritional obesity is unexplored. To examine this, we use gene-modified mice with EC-specific overexpression of human IGF-1R (hIGFREO) and their wild-type littermates. After high-fat feeding, hIGFREO weigh less, have reduced adiposity and have improved glucose tolerance. hIGFREO show an altered gene expression and altered microbial diversity in the gut, including a relative increase in the beneficial genus Akkermansia. The depletion of gut microbiota with broad-spectrum antibiotics induces a loss of the favourable metabolic differences seen in hIGFREO mice. We show that IGF-1R facilitates crosstalk between the EC and the gut wall; this crosstalk protects against diet-induced obesity, as a result of an altered gut microbiota.

Safety and efficacy of interrupting dual antiplatelet therapy one month following percutaneous coronary intervention: a meta-analysis of randomized controlled trials.

Very short duration of dual antiplatelet therapy (DAPT) following percutaneous coronary intervention (PCI) has recently attracted a lot of attention with the introduction of newer generations stents. This is appealing, especially in patients at high bleeding risk. However, none of the trials were powered for the individual ischemic and bleeding endpoints. All randomised controlled trials (RCTs) investigating one-month versus routine duration of DAPT in patients undergoing PCI and reporting outcomes from the time of cessation of DAPT (1 month) to 1 year were eligible for inclusion in the meta-analysis. The pooled risk ratios (RR) with their 95% confidence interval (CI) were calculated with the random-effects model using the Mantel-Haenszel method. Four RCTs involving 26,576 patients were included in this meta-analysis. Cessation of DAPT after 1 month was associated with significantly less major bleeding [RR 0.70, 95%CI (0.51-0.95), P = 0.02, heterogeneity (I2) = 42%]. There was no statistically significant difference in all-cause mortality [RR 0.84 (95%CI 0.69-1.03), P = 0.10, I2 = 0%] and stroke [RR 0.71 (95%CI 0.45-1.13), P = 0.15, I2 = 42%] when compared to routine duration of DAPT. There was also no difference in myocardial infarction (MI) [RR 1.12 (95%CI 0.91-1.39), P = 0.28, I2 = 0%], and definite or probable stent thrombosis [RR 1.49 (95%CI 0.92-2.41), P = 0.11, I2 = 0%] with cessation of DAPT after 1 month. Cessation of DAPT 1 month after PCI was associated with significantly less major bleeding, but there was no difference in the rate of all-cause mortality, stroke, MI and stent thrombosis.

Divergent effects of genetic and pharmacological inhibition of Nox2 NADPH oxidase on insulin resistance-related vascular damage.

Insulin resistance leads to excessive endothelial cell (EC) superoxide generation and accelerated atherosclerosis. The principal source of superoxide from the insulin-resistant endothelium is the Nox2 isoform of NADPH oxidase. Here we examine the therapeutic potential of Nox2 inhibition on superoxide generation in saphenous vein ECs (SVECs) from patients with advanced atherosclerosis and type 2 diabetes and on vascular function, vascular damage, and lipid deposition in apolipoprotein E-deficient (ApoE-/-) mice with EC-specific insulin resistance (ESMIRO). To examine the effect of genetic inhibition of Nox2, ESMIRO mice deficient in ApoE-/- and Nox2 (ESMIRO/ApoE-/-/Nox2-/y) were generated and compared with ESMIRO/ApoE-/-/Nox2+/y littermates. To examine the effect of pharmacological inhibition of Nox2, we administered gp91dstat or scrambled peptide to ESMIRO/ApoE-/- mice. SVECs from diabetic patients had increased expression of Nox2 protein with concomitant increase in superoxide generation, which could be reduced by the Nox2 inhibitor gp91dstat. After 12 wk Western diet, ESMIRO/ApoE-/-/Nox2-/y mice had reduced EC superoxide generation and greater aortic relaxation to acetylcholine. ESMIRO/ApoE-/-/Nox2-/y mice developed more lipid deposition in the thoraco-abdominal aorta with multiple foci of elastin fragmentation at the level of the aortic sinus and greater expression of intercellular adhesion molecule-1 (ICAM-1). Gp91dstat reduced EC superoxide and lipid deposition in the thoraco-abdominal aorta of ESMIRO/ApoE-/- mice without causing elastin fragmentation or increased ICAM-1 expression. These results demonstrate that insulin resistance is characterized by increased Nox2-derived vascular superoxide. Complete deletion of Nox2 in mice with EC insulin resistance exacerbates, whereas partial pharmacological Nox2 inhibition protects against, insulin resistance-induced vascular damage.

Selective Enhancement of Insulin Sensitivity in the Endothelium In Vivo Reveals a Novel Proatherosclerotic Signaling Loop.

RATIONALE: In the endothelium, insulin stimulates endothelial NO synthase (eNOS) to generate the antiatherosclerotic signaling radical NO. Insulin-resistant type 2 diabetes mellitus is associated with reduced NO availability and accelerated atherosclerosis. The effect of enhancing endothelial insulin sensitivity on NO availability is unclear. OBJECTIVE: To answer this question, we generated a mouse with endothelial cell (EC)-specific overexpression of the human insulin receptor (hIRECO) using the Tie2 promoter-enhancer. METHODS AND RESULTS: hIRECO demonstrated significant endothelial dysfunction measured by blunted endothelium-dependent vasorelaxation to acetylcholine, which was normalized by a specific Nox2 NADPH oxidase inhibitor. Insulin-stimulated phosphorylation of protein kinase B was increased in hIRECO EC as was Nox2 NADPH oxidase-dependent generation of superoxide, whereas insulin-stimulated and shear stress-stimulated eNOS activations were blunted. Phosphorylation at the inhibitory residue Y657 of eNOS and expression of proline-rich tyrosine kinase 2 that phosphorylates this residue were significantly higher in hIRECO EC. Inhibition of proline-rich tyrosine kinase 2 improved insulin-induced and shear stress-induced eNOS activation in hIRECO EC. CONCLUSIONS: Enhancing insulin sensitivity specifically in EC leads to a paradoxical decline in endothelial function, mediated by increased tyrosine phosphorylation of eNOS and excess Nox2-derived superoxide. Increased EC insulin sensitivity leads to a proatherosclerotic imbalance between NO and superoxide. Inhibition of proline-rich tyrosine kinase 2 restores insulin-induced and shear stress-induced NO production. This study demonstrates for the first time that increased endothelial insulin sensitivity leads to a proatherosclerotic imbalance between NO and superoxide.

VEGFR2 Trafficking, Signaling and Proteolysis is Regulated by the Ubiquitin Isopeptidase USP8.

Vascular endothelial growth factor A (VEGF-A) regulates many aspects of vascular function. VEGF-A binding to vascular endothelial growth factor receptor 2 (VEGFR2) stimulates endothelial signal transduction and regulates multiple cellular responses. Activated VEGFR2 undergoes ubiquitination but the enzymes that regulate this post-translational modification are unclear. In this study, the de-ubiquitinating enzyme, USP8, is shown to regulate VEGFR2 trafficking, de-ubiquitination, proteolysis and signal transduction. USP8-depleted endothelial cells displayed altered VEGFR2 ubiquitination and production of a unique VEGFR2 extracellular domain proteolytic fragment caused by VEGFR2 accumulation in the endosome-lysosome system. In addition, perturbed VEGFR2 trafficking impaired VEGF-A-stimulated signal transduction in USP8-depleted cells. Thus, regulation of VEGFR2 ubiquitination and de-ubiquitination has important consequences for the endothelial cell response and vascular physiology.

Restoring Akt1 activity in outgrowth endothelial cells from South Asian men rescues vascular reparative potential.

Recent data suggest reduced indices of vascular repair in South Asian men, a group at increased risk of cardiovascular events. Outgrowth endothelial cells (OEC) represent an attractive tool to study vascular repair in humans and may offer potential in cell-based repair therapies. We aimed to define and manipulate potential mechanisms of impaired vascular repair in South Asian (SA) men. In vitro and in vivo assays of vascular repair and angiogenesis were performed using OEC derived from SA men and matched European controls, prior defining potentially causal molecular mechanisms. SA OEC exhibited impaired colony formation, migration, and in vitro angiogenesis, associated with decreased expression of the proangiogenic molecules Akt1 and endothelial nitric oxide synthase (eNOS). Transfusion of European OEC into immunodeficient mice after wire-induced femoral artery injury augmented re-endothelialization, in contrast with SA OEC and vehicle; SA OEC also failed to promote angiogenesis after induction of hind limb ischemia. Expression of constitutively active Akt1 (E17KAkt), but not green fluorescent protein control, in SA OEC increased in vitro angiogenesis, which was abrogated by a NOS antagonist. Moreover, E17KAkt expressing SA OEC promoted re-endothelialization of wire-injured femoral arteries, and perfusion recovery of ischemic limbs, to a magnitude comparable with nonmanipulated European OEC. Silencing Akt1 in European OEC recapitulated the functional deficits noted in SA OEC. Reduced signaling via the Akt/eNOS axis is causally linked with impaired OEC-mediated vascular repair in South Asian men. These data prove the principle of rescuing marked reparative dysfunction in OEC derived from these men.

Vascular endothelial growth factors: multitasking functionality in metabolism, health and disease.

Vascular endothelial growth factors (VEGFs) bind to VEGF receptor tyrosine kinases (VEGFRs). The VEGF and VEGFR gene products regulate diverse regulatory pathways in mammalian development, health and disease. The interaction between a particular VEGF and its cognate VEGFR activates multiple signal transduction pathways which regulate different cellular responses including metabolism, gene expression, proliferation, migration, and survival. The family of VEGF isoforms regulate vascular physiology and promote tissue homeostasis. VEGF dysfunction is implicated in major chronic disease states including atherosclerosis, diabetes, and cancer. More recent studies implicate a strong link between response to VEGF and regulation of vascular metabolism. Understanding how this family of multitasking cytokines regulates cell and animal function has implications for treating many different diseases.

Haploinsufficiency of the insulin-like growth factor-1 receptor enhances endothelial repair and favorably modifies angiogenic progenitor cell phenotype.

OBJECTIVES: Defective endothelial regeneration predisposes to adverse arterial remodeling and is thought to contribute to cardiovascular disease in type 2 diabetes mellitus. We recently demonstrated that the type 1 insulin-like growth factor receptor (IGF1R) is a negative regulator of insulin sensitivity and nitric oxide bioavailability. In this report, we examined partial deletion of the IGF1R as a potential strategy to enhance endothelial repair. APPROACH AND RESULTS: We assessed endothelial regeneration after wire injury in mice and abundance and function of angiogenic progenitor cells in mice with haploinsufficiency of the IGF1R (IGF1R(+/-)). Endothelial regeneration after arterial injury was accelerated in IGF1R(+/-) mice. Although the yield of angiogenic progenitor cells was lower in IGF1R(+/-) mice, these angiogenic progenitor cells displayed enhanced adhesion, increased secretion of insulin-like growth factor-1, and enhanced angiogenic capacity. To examine the relevance of IGF1R manipulation to cell-based therapy, we transfused IGF1R(+/-) bone marrow-derived CD117(+) cells into wild-type mice. IGF1R(+/-) cells accelerated endothelial regeneration after arterial injury compared with wild-type cells and did not alter atherosclerotic lesion formation. CONCLUSIONS: Haploinsufficiency of the IGF1R is associated with accelerated endothelial regeneration in vivo and enhanced tube forming and adhesive potential of angiogenic progenitor cells in vitro. Partial deletion of IGF1R in transfused bone marrow-derived CD117(+) cells enhanced their capacity to promote endothelial regeneration without altering atherosclerosis. Our data suggest that manipulation of the IGF1R could be exploited as novel therapeutic approach to enhance repair of the arterial wall after injury.

Sodium-glucose cotransporter 2 inhibitors influence skeletal muscle pathology in patients with heart failure and reduced ejection fraction.

AIMS: Patients with heart failure and reduced ejection fraction (HFrEF) exhibit skeletal muscle pathology, which contributes to symptoms and decreased quality of life. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) improve clinical outcomes in HFrEF but their mechanism of action remains poorly understood. We aimed, therefore, to determine whether SGLT2i influence skeletal muscle pathology in patients with HFrEF. METHODS AND RESULTS: Muscle biopsies from 28 male patients with HFrEF (New York Heart association class I-III) treated with SGLT2i (>12 months) or without SGLT2i were compared. Comprehensive analyses of muscle structure (immunohistochemistry), transcriptome (RNA sequencing), and metabolome (liquid chromatography-mass spectrometry) were performed, and serum inflammatory profiling (ELISA). Experiments in mice (n = 16) treated with SGLT2i were also performed. Myofiber atrophy was ~20% less in patients taking SGLT2i (p = 0.07). Transcriptomics and follow-up measures identified a unique signature in patients taking SGLT2i related to beneficial effects on atrophy, metabolism, and inflammation. Metabolomics identified influenced tryptophan metabolism in patients taking SGLT2i: kynurenic acid was 24% higher and kynurenine was 32% lower (p < 0.001). Serum profiling identified that SGLT2i treatment was associated with lower (p < 0.05) pro-inflammatory cytokines by 26-64% alongside downstream muscle interleukin (IL)-6-JAK/STAT3 signalling (p = 008 and 0.09). Serum IL-6 and muscle kynurenine were correlated (R = 0.65; p < 0.05). Muscle pathology was lower in mice treated with SGLT2i indicative of a conserved mammalian response to treatment. CONCLUSIONS: Treatment with SGLT2i influenced skeletal muscle pathology in patients with HFrEF and was associated with anti-atrophic, anti-inflammatory, and pro-metabolic effects. These changes may be regulated via IL-6-kynurenine signalling. Together, clinical improvements following SGLT2i treatment in patients with HFrEF may be partly explained by their positive effects on skeletal muscle pathology.

Sex Differences in Skeletal Muscle Pathology in Patients With Heart Failure and Reduced Ejection Fraction.

BACKGROUND: Women with heart failure and reduced ejection fraction (HFrEF) have greater symptoms and a lower quality of life compared with men; however, the role of noncardiac mechanisms remains poorly resolved. We hypothesized that differences in skeletal muscle pathology between men and women with HFrEF may explain clinical heterogeneity. METHODS: Muscle biopsies from both men (n=22) and women (n=16) with moderate HFrEF (New York Heart Association classes I-III) and age- and sex-matched controls (n=18 and n=16, respectively) underwent transcriptomics (RNA-sequencing), myofiber structural imaging (histology), and molecular signaling analysis (gene/protein expression), with serum inflammatory profiles analyzed (enzyme-linked immunosorbent assay). Two-way ANOVA was conducted (interaction sex and condition). RESULTS: RNA-sequencing identified 5629 differentially expressed genes between men and women with HFrEF, with upregulated terms for catabolism and downregulated terms for mitochondria in men. mRNA expression confirmed an effect of sex (P<0.05) on proatrophic genes related to ubiquitin proteasome, autophagy, and myostatin systems (higher in all men versus all women), whereas proanabolic IGF1 expression was higher (P<0.05) in women with HFrEF only. Structurally, women compared with men with HFrEF showed a pro-oxidative phenotype, with smaller but higher numbers of type I fibers, alongside higher muscle capillarity (Pinteraction<0.05) and higher type I fiber areal density (Pinteraction<0.05). Differences in gene/protein expression of regulators of muscle phenotype were detected between sexes, including HIF1α, ESR1, VEGF (vascular endothelial growth factor), and PGC1α expression (P<0.05), and for upstream circulating factors, including VEGF, IL (interleukin)-6, and IL-8 (P<0.05). CONCLUSIONS: Sex differences in muscle pathology in HFrEF exist, with men showing greater abnormalities compared with women related to the transcriptome, fiber phenotype, capillarity, and circulating factors. These preliminary data question whether muscle pathology is a primary mechanism contributing to greater symptoms in women with HFrEF and highlight the need for further investigation.

Whole body insulin resistance leads to accelerated atherosclerosis: role for Nox2 NADPH oxidase.

Insulin resistance underpins the progression of type 2 diabetes mellitus and leads to a collection of risk factors for the development of atherosclerosis. Whether or not insulin resistance at a whole body level per se leads to accelerated atherosclerosis is unclear. To answer this question we generated atherosclerosis prone mice with whole body insulin resistance secondary to haploinsufficiency of the insulin receptor (IR+/-) deficient in ApoE-/- (IR+/-/ApoE-/-). IR+/-/ApoE-/- and ApoE-/- littermates had similar weight, lipids and glucose tolerance at baseline. After 12 weeks Western high cholesterol diet, IR+/-/ApoE-/- had significantly more atherosclerosis in the thoracoabdominal aorta and at the level of the aortic sinus than ApoE-/- littermates. Excess Nox2 NADPH oxidase (Nox2) derived superoxide has been suggested to underpin diabetes related atherosclerosis. In IR+/-/ApoE-/- we examined the effect of inhibiting Nox2 using genetic or pharmacological approaches on the development of atherosclerosis. To genetically delete Nox2 we generated IR+/-/ApoE-/-/Nox2-/y and to inhibit Nox2 pharmacologically we treated IR+/-/ApoE-/- with the peptide Nox2 inhibitor gp91dstat. IR+/-/ApoE-/-/Nox2-/y had significant disruption of the aortic wall with increased thoracoabdominal atherosclerosis when compared to IR+/-/ApoE-/-/Nox2+/y littermates. Inhibition of Nox2 using gp91dstat reduced atherosclerosis in the thoracoabdominal aorta of IR+/-/ApoE-/-. Whole body insulin resistance accelerates the development of atherosclerosis. Genetic inhibition of Nox2 leads to disruption of the aortic wall in IR+/-/ApoE-/- mice with accelerated atherosclerosis whereas pharmacological Nox2 inhibition reduces atherosclerosis in IR+/-/ApoE-/- without disruption of the arterial wall.

Diabetes mellitus does not alter mortality or hospitalisation risk in patients with newly diagnosed heart failure with preserved ejection fraction: Time to rethink pathophysiological models of disease progression.

INTRODUCTION: Type 2 diabetes is a common and adverse prognostic co-morbidity for patients with heart failure with reduced ejection fraction (HFrEF). The effect of diabetes on long-term outcomes for heart failure with preserved ejection fraction (HFpEF) is less established. METHODS: Prospective cohort study of patients referred to a regional HF clinic with newly diagnosed with HFrEF and HFpEF according to the 2016 European Society of Cardiology guidelines. The association between diabetes, all-cause mortality and hospitalisation was quantified using Kaplan-Meier or Cox regression analysis. RESULTS: Between 1st May 2012 and 1st May 2013, of 960 unselected consecutive patients referred with suspected HF, 464 and 314 patients met the criteria for HFpEF and HFrEF respectively. Within HFpEF and HFrEF groups, patients with diabetes were more frequently male and in both groups patients with diabetes were more likely to be treated with ß-adrenoceptor antagonists and angiotensin converting enzyme inhibitors. After adjustment for age, sex, medical therapy and co-morbidities, diabetes was associated with increased mortality in individuals with HFrEF (HR 1.46 95% CI: 1.05-2.02; p = .023), but not in those with HFpEF (HR 1.26 95% CI 0.92-1.72; p = .146). CONCLUSION: In unselected patients with newly diagnosed HF, diabetes is not an adverse prognostic marker in patients with HFpEF, but is in HFrEF.

Small molecule modulation of insulin receptor-insulin like growth factor-1 receptor heterodimers in human endothelial cells.

OBJECTIVES: The insulin receptor (IR) and insulin like growth factor-1 receptor (IGF-1R) are heterodimers consisting of two extracellular α-subunits and two transmembrane ß -subunits. Insulin αß and insulin like growth factor-1 αß hemi-receptors can heterodimerize to form hybrids composed of one IR αß and one IGF-1R αß. The function of hybrids in the endothelium is unclear. We sought insight by developing a small molecule capable of reducing hybrid formation in endothelial cells. METHODS: We performed a high-throughput small molecule screening, based on a homology model of the apo hybrid structure. Endothelial cells were studied using western blotting and qPCR to determine the effects of small molecules that reduced hybrid formation. RESULTS: Our studies unveil a first-in-class quinoline-containing heterocyclic small molecule that reduces hybrids by >50% in human umbilical vein endothelial cells (HUVECs) with no effects on IR or IGF-1R. This small molecule reduced expression of the negative regulatory p85α subunit of phosphatidylinositol 3-kinase, increased basal phosphorylation of the downstream target Akt and enhanced insulin/insulin-like growth factor-1 and shear stress-induced serine phosphorylation of Akt. In primary saphenous vein endothelial cells (SVEC) from patients with type 2 diabetes mellitus undergoing coronary artery bypass (CABG) surgery, hybrid receptor expression was greater than in patients without type 2 diabetes mellitus. The small molecule significantly reduced hybrid expression in SVEC from patients with type 2 diabetes mellitus. CONCLUSIONS: We identified a small molecule that decreases the formation of IR: IGF-1R hybrid receptors in human endothelial cells, without significant impact on the overall expression of IR or IGF-1R. In HUVECs, reduction of IR: IGF-1R hybrid receptors leads to an increase in insulin-induced serine phosphorylation of the critical downstream signalling kinase, Akt. The underpinning mechanism appears, at least in part to involve the attenuation of the inhibitory effect of IR: IGF-1R hybrid receptors on PI3-kinase signalling.

Distinct, common and synergistic effects of insulin and IGF-1 receptors on healthy murine ageing.

Objective: Reduced IGF-1 signalling is an evolutionarily conserved mediator of longevity, yet the magnitude of this effect is substantially larger in organisms retaining a common insulin and IGF-1 receptor. Whether this reflects the failure to simultaneously reduce IGF-1 and insulin signalling in mammalian model systems remains unexplored, as is the associated impact on markers of healthy ageing. We set out to address these uncertainties. Methods: We compared the duration of healthy life (healthspan) in male mice with haploinsufficiency of the insulin receptor (IRKO), IGF-1 receptor (IGF-1RKO), or both (DKO), versus wildtype (WT) littermates. Cognitive performance was defined using nesting studies at 3- and 24-months of age. Brain transcriptome was characterised at 3- and 18-months of age using RNA-seq. Results: Healthspan was longer in DKO versus WT, with IRKO and IGF-1RKO being intermediate. At 2 years of age, DKO also exhibited preserved nesting behaviour in contrast with all other genotypes. Differential insulin sensitivity or weight gain during ageing did not explain the preserved healthspan of DKO, since these were comparable to IRKO littermates. Brain transcriptomics at 18 months of age revealed lower expression of canonical ageing-associated genes in DKO versus WT, although many of these findings were replicated in IRKO versus WT or IGF-1RKO vs WT. Conclusions: Reduced insulin and IGF-1 receptor expression have both common and synergistic effects upon elements of healthy mammalian ageing, suggesting future ageing studies should consider targeting both insulin and IGF-1 signalling.

Coronary Guidewires in Temporary Cardiac Pacing and Assessment of Myocardial Viability: Current Perspectives and Future Directions.

Intracoronary guidewires used in percutaneous coronary intervention can also be configured to provide temporary ventricular pacing. Trans coronary electrophysiological parameters recorded by employing coronary guidewires may have a potential role in assessing myocardial viability and could provide a means to make an immediate on-table decision about revascularisation. To date, some small studies have demonstrated the safety of this technique in temporary cardiac pacing, but further research is required to refine this approach and establish its clinical utility in myocardial viability assessment. In this review we discuss the potential role of trans coronary electrophysiology in the assessment of myocardial viability.

Imaging Real-Time Coronary Anatomy Using a Three-Dimensional Electrophysiology Mapping System.

The aim of this study is to evaluate the feasibility of creating fast three-dimensional maps of coronary arteries and to develop a bipolar coronary guidewire in vitro and determine whether it can be localised accurately within the model.A total of five patients were recruited, and EnSite Precision was utilised to create 3D coronary anatomy. A water bath to accommodate a 3D-printed coronary model was developed to test the performance of the bipolar angioplasty wire.Successful guidewire localisation and 3D reconstruction of coronary anatomy were achieved in all the cases. No complications. The bipolar wire was able to collect point clouds, and localisation of the distal tip was excellent when tested in the water bath.Our study demonstrates the feasibility and safety of utilising EAMS to collect coronary anatomy. Real-time tracking with a bipolar catheter is accurate when tested in vitro.

Loss of IGFBP2 mediates alveolar type 2 cell senescence and promotes lung fibrosis.

Accumulation of senescent cells contributes to age-related diseases including idiopathic pulmonary fibrosis (IPF). Insulin-like growth factor binding proteins (IGFBPs) regulate many biological processes; however, the functional contributions of IGFBP2 in lung fibrosis remain largely unclear. Here, we report that intranasal delivery of recombinant IGFBP2 protects aged mice from weight loss and demonstrated antifibrotic effects after bleomycin lung injury. Notably, aged human-Igfbp2 transgenic mice reveal reduced senescence and senescent-associated secretory phenotype factors in alveolar epithelial type 2 (AEC2) cells and they ameliorated bleomycin-induced lung fibrosis. Finally, we demonstrate that IGFBP2 expression is significantly suppressed in AEC2 cells isolated from fibrotic lung regions of patients with IPF and/or pulmonary hypertension compared with patients with hypersensitivity pneumonitis and/or chronic obstructive pulmonary disease. Altogether, our study provides insights into how IGFBP2 regulates AEC2-cell-specific senescence and that restoring IGFBP2 levels in fibrotic lungs can prove effective for patients with IPF.