Insulin Resistance Impairs Circulating Angiogenic Progenitor Cell Function and Delays Endothelial Regeneration

OBJECTIVE Circulating angiogenic progenitor cells (APCs) participate in endothelial repair after arterial injury. Type 2 diabetes is associated with fewer circulating APCs, APC dysfunction, and impaired endothelial repair. We set out to determine whether insulin resistance adversely affects APCs and endothelial regeneration. RESEARCH DESIGN AND METHODS We quantified APCs and assessed APC mobilization and function in mice hemizygous for knockout of the insulin receptor (IRKO) and wild-type (WT) littermate controls. Endothelial regeneration after femoral artery wire injury was also quantified after APC transfusion. RESULTS IRKO mice, although glucose tolerant, had fewer circulating Sca-1+/Flk-1+ APCs than WT mice. Culture of mononuclear cells demonstrated that IRKO mice had fewer APCs in peripheral blood, but not in bone marrow or spleen, suggestive of a mobilization defect. Defective vascular endothelial growth factor–stimulated APC mobilization was confirmed in IRKO mice, consistent with reduced endothelial nitric oxide synthase (eNOS) expression in bone marrow and impaired vascular eNOS activity. Paracrine angiogenic activity of APCs from IRKO mice was impaired compared with those from WT animals. Endothelial regeneration of the femoral artery after denuding wire injury was delayed in IRKO mice compared with WT. Transfusion of mononuclear cells from WT mice normalized the impaired endothelial regeneration in IRKO mice. Transfusion of c-kit+ bone marrow cells from WT mice also restored endothelial regeneration in IRKO mice. However, transfusion of c-kit+ cells from IRKO mice was less effective at improving endothelial repair. CONCLUSIONS Insulin resistance impairs APC function and delays endothelial regeneration after arterial injury. These findings support the hypothesis that insulin resistance per se is sufficient to jeopardize endogenous vascular repair. Defective endothelial repair may be normalized by transfusion of APCs from insulin-sensitive animals but not from insulin-resistant animals

Prioritizing symptom management in the treatment of chronic heart failure

Chronic heart failure (CHF) is a chronic, progressive disease that has detrimental consequences on a patient's quality of life (QoL). In part due to requirements for market access and licensing, the assessment of current and future treatments focuses on reducing mortality and hospitalizations. Few drugs are available principally for their symptomatic effect despite the fact that most patients' symptoms persist or worsen over time and an acceptance that the survival gains of modern therapies are mitigated by poorly controlled symptoms. Additional contributors to the failure to focus on symptoms could be the result of under‐reporting of symptoms by patients and carers and a reliance on insensitive symptomatic categories in which patients frequently remain despite additional therapies. Hence, formal symptom assessment tools, such as questionnaires, can be useful prompts to encourage more fidelity and reproducibility in the assessment of symptoms. This scoping review explores for the first time the assessment options and management of common symptoms in CHF with a focus on patient‐reported outcome tools. The integration of patient‐reported outcomes for symptom assessment into the routine of a CHF clinic could improve the monitoring of disease progression and QoL, especially following changes in treatment or intervention with a targeted symptom approach expected to improve QoL and patient outcomes

Novel Role of the IGF-1 Receptor in Endothelial Function and Repair: Studies in Endothelium-Targeted IGF-1 Receptor Transgenic Mice

We recently demonstrated that reducing IGF-1 receptor (IGF-1R) numbers in the endothelium enhances nitric oxide (NO) bioavailability and endothelial cell insulin sensitivity. In the present report, we aimed to examine the effect of increasing IGF-1R on endothelial cell function and repair. To examine the effect of increasing IGF-1R in the endothelium, we generated mice overexpressing human IGF-1R in the endothelium (human IGF-1R endothelium-overexpressing mice [hIGFREO]) under direction of the Tie2 promoter enhancer. hIGFREO aorta had reduced basal NO bioavailability (percent constriction to NG-monomethyl-l-arginine [mean (SEM) wild type 106% (30%); hIGFREO 48% (10%)]; P < 0.05). Endothelial cells from hIGFREO had reduced insulin-stimulated endothelial NO synthase activation (mean [SEM] wild type 170% [25%], hIGFREO 58% [3%]; P = 0.04) and insulin-stimulated NO release (mean [SEM] wild type 4,500 AU [1,000], hIGFREO 1,500 AU [700]; P < 0.05). hIGFREO mice had enhanced endothelium regeneration after denuding arterial injury (mean [SEM] percent recovered area, wild type 57% [2%], hIGFREO 47% [5%]; P < 0.05) and enhanced endothelial cell migration in vitro. The IGF-1R, although reducing NO bioavailability, enhances in situ endothelium regeneration. Manipulating IGF-1R in the endothelium may be a useful strategy to treat disorders of vascular growth and repair. Insulin-resistant type 2 diabetes characterized by perturbation of the insulin/IGF-1 system is a multisystem disorder of nutrient homeostasis, cell growth, and tissue repair (1). As a result, type 2 diabetes is a major risk factor for the development of a range of disorders of human health, including occlusive coronary artery disease (2), peripheral vascular disease (3), stroke (4), chronic vascular ulcers (5), proliferative retinopathy (6), and nephropathy (7). A key hallmark of these pathologies is endothelial cell dysfunction characterized by a reduction in bioavailability of the signaling radical nitric oxide (NO). In the endothelium, insulin binding to its tyrosine kinase receptor stimulates release of NO (8). Insulin resistance at a whole-body level (9,10) and specific to the endothelium (11) leads to reduced bioavailability of NO, indicative of a critical role for insulin in regulating NO bioavailability. The insulin receptor (IR) and IGF-1 receptor (IGF-1R) are structurally similar—both composed of two extracellular α and two transmembrane β subunits linked by disulfide bonds (12). As a result, IGF-1R and IR can heterodimerize to form insulin-resistant hybrid receptors composed of one IGF-1R-αβ complex and one IR-αβ subunit complex (13,14). We recently demonstrated that reducing IGF-1R (by reducing the number of hybrid receptors) enhances insulin sensitivity and NO bioavailability in the endothelium (15). To examine the effect of increasing IGF-1R specifically in the endothelium on NO bioavailability, endothelial repair, and metabolic homeostasis, we generated a transgenic mouse with targeted overexpression of the human IGF-1R in the endothelium (hIGFREO)

Effect of disease-modifying agents and their association with mortality in multi-morbid patients with heart failure with reduced ejection fraction

Aims An increasing proportion of patients with heart failure with reduced ejection fraction (HFrEF) have co‐morbidities. The effect of these co‐morbidities on modes of death and the effect of disease‐modifying agents in multi‐morbid patients is unknown. Methods and results We performed a prospective cohort study of ambulatory patients with HFrEF to assess predictors of outcomes. We identified four key co‐morbidities—ischaemic aetiology of heart failure, diabetes mellitus, chronic obstructive pulmonary disease (COPD), and chronic kidney disease (CKD)—that were highly prevalent and associated with an increased risk of all‐cause mortality. We used these data to explore modes of death and the utilization of disease‐modifying agents in patients with and without these co‐morbidities. The cohort included 1789 consecutively recruited patients who had an average age of 69.6 ± 12.5 years, and 1307 (73%) were male. Ischaemic aetiology of heart failure was the most common co‐morbidity, occurring in 1061 (59%) patients; 503 (28%) patients had diabetes mellitus, 283 (16%) had COPD, and 140 (8%) had CKD stage IV/V. During mean follow‐up of 3.8 ± 1.6 years, 737 (41.5%) patients died, classified as progressive heart failure (n = 227, 32%), sudden (n = 112, 16%), and non‐cardiovascular deaths (n = 314, 44%). Multi‐morbid patients were older (P 2.5‐fold and 1.5‐fold increased risk of sudden death, whilst higher doses of beta‐adrenoceptor antagonists were protective (hazard ratio per milligram 0.92, 95% confidence interval 0.86–0.98, P = 0.009). Each milligram of bisoprolol‐equivalent beta‐adrenoceptor antagonist was associated with 9% (P = 0.001) and 11% (P = 0.023) reduction of sudden deaths in patients with <2 and ≥2 co‐morbidities, respectively. Conclusions Higher doses of beta‐adrenoceptor antagonist are associated with greater protection from sudden death, most evident in multi‐morbid patients. Patients with COPD who appear to be at the highest risk of sudden death are prescribed the lowest doses and less likely to be implanted with implantable cardioverter defibrillators, which might represent a missed opportunity to optimize safe and proven therapies for these patients

Infection-Related Hospitalization in Heart Failure With Reduced Ejection Fraction: A Prospective Observational Cohort Study

Background: Hospitalization is a common adverse event in people with heart failure and reduced ejection fraction, yet is often not primarily due to decompensated heart failure (HF). We investigated the long-term prognosis following infection-related hospitalization. Methods: We conducted a prospective observational cohort study of 711 people with heart failure and reduced ejection fraction recruited from 4 specialist HF clinics in the United Kingdom. All hospitalization episodes (n=1568) were recorded and categorized as primarily due to decompensated HF, other cardiovascular disease, infection-related, or other noncardiovascular disease. Survival was determined after the first hospitalization. Results: During 2900 patient-years of follow-up, there were a total of 14 686 hospital days. At least one hospitalization occurred in 467 people (66%); 25% of first hospitalizations were primarily due to infection and these were not associated with typical signs including tachycardia and pyrexia. Compared with other categories of hospitalization, infection-related was associated with older age, lower serum albumin, higher blood neutrophil counts, and greater prevalence of chronic obstructive pulmonary disease at recruitment. Median survival after first infection-related hospitalization was 18.6 months, comparable to that after first decompensated HF hospitalization, even after age-sex adjustment. The burden of all-cause rehospitalization was comparable irrespective of the category of first hospitalization, but infection more commonly caused re-hospitalization after index infection hospitalization. Conclusions: Infection is a common driver of hospitalization in heart failure and reduced ejection fraction and often presents without classical signs. It is associated with high mortality rates, comparable to decompensated HF, and a major burden of rehospitalization caused by recurrent episodes of infection

Chronic heart failure with diabetes mellitus is characterized by a severe skeletal muscle pathology

Background Patients with coexistent chronic heart failure (CHF) and diabetes mellitus (DM) demonstrate greater exercise limitation and worse prognosis compared with CHF patients without DM, even when corrected for cardiac dysfunction. Understanding the origins of symptoms in this subgroup may facilitate development of targeted treatments. We therefore characterized the skeletal muscle phenotype and its relationship to exercise limitation in patients with diabetic heart failure (D‐HF). Methods In one of the largest muscle sampling studies in a CHF population, pectoralis major biopsies were taken from age‐matched controls (n = 25), DM (n = 10), CHF (n = 52), and D‐HF (n = 28) patients. In situ mitochondrial function and reactive oxygen species, fibre morphology, capillarity, and gene expression analyses were performed and correlated to whole‐body exercise capacity. Results Mitochondrial respiration, content, coupling efficiency, and intrinsic function were lower in D‐HF patients compared with other groups (P < 0.05). A unique mitochondrial complex I dysfunction was present in D‐HF patients only (P < 0.05), which strongly correlated to exercise capacity (R2 = 0.64; P < 0.001). Mitochondrial impairments in D‐HF corresponded to higher levels of mitochondrial reactive oxygen species (P < 0.05) and lower gene expression of anti‐oxidative enzyme superoxide dismutase 2 (P < 0.05) and complex I subunit NDUFS1 (P < 0.05). D‐HF was also associated with severe fibre atrophy (P < 0.05) and reduced local fibre capillarity (P < 0.05). Conclusions Patients with D‐HF develop a specific skeletal muscle pathology, characterized by mitochondrial impairments, fibre atrophy, and derangements in the capillary network that are linked to exercise intolerance. These novel preliminary data support skeletal muscle as a potential therapeutic target for treating patients with D‐HF

A systematic review of the effectiveness of universal Health Visitor led Child Health Clinics

This paper presents the findings of a systematic review undertaken to assess how effectively health visitor led child health clinics (‘baby clinics’) contribute to the promotion of pre-school child health and the reduction of health inequalities.Despite the widespread presence of baby clinics across the UK, there is little published research about the service model, its purpose or effectiveness. The initial search produced 559 articles, after removing duplicates, 175 abstracts were assessed against the inclusion criteria and 24 qualitative studies were identified as relevant to the review. No studies were excluded based on quality issues, however the quality of studies was variable. Thematic analysis was used to organise and interpret the data. Although the review presents a synthesis of research over the last 30 years, there is a lack of evaluative research about the structure, process and outcomes of baby clinics, which makes it impossible to draw any conclusions about the effectiveness of the service offer. Findings suggest research on the value and purpose of baby clinics is now needed and whilst good evaluation studies with clear outcome measures are sought, it is clear that the theoretical processes through which positive outcomes are promoted need to be established first

Unique Transcriptome Signature Distinguishes Patients With Heart Failure With Myopathy

Background People with chronic heart failure (CHF) experience severe skeletal muscle dysfunction, characterized by mitochondrial abnormalities, which exacerbates the primary symptom of exercise intolerance. However, the molecular triggers and characteristics underlying mitochondrial abnormalities caused by CHF remain poorly understood. Methods and Results We recruited 28 patients with CHF caused by reduced ejection fraction and 9 controls. We simultaneously biopsied skeletal muscle from the pectoralis major in the upper limb and from the vastus lateralis in the lower limb. We phenotyped mitochondrial function in permeabilized myofibers from both sites and followed this by complete RNA sequencing to identify novel molecular abnormalities in CHF skeletal muscle. Patients with CHF presented with upper and lower limb skeletal muscle impairments to mitochondrial function that were of a similar deficit and indicative of a myopathy. Mitochondrial abnormalities were strongly correlated to symptoms. Further RNA sequencing revealed a unique transcriptome signature in CHF skeletal muscle characterized by a novel triad of differentially expressed genes related to deficits in energy metabolism including adenosine monophosphate deaminase 3, pyridine nucleotide‐disulphide oxidoreductase domain 2, and lactate dehydrogenase C. Conclusions Our data suggest an upper and lower limb metabolic myopathy that is characterized by a unique transcriptome signature in skeletal muscle of humans with CHF

Moderate and heavy metabolic stress interval training improve arterial stiffness and heart rate dynamics in humans

Traditional continuous aerobic exercise training attenuates age-related increases of arterial stiffness, however, training studies have not determined whether metabolic stress impacts these favourable effects. Twenty untrained healthy participants (n = 11 heavy metabolic stress interval training, n = 9 moderate metabolic stress interval training) completed 6 weeks of moderate or heavy intensity interval training matched for total work and exercise duration. Carotid artery stiffness, blood pressure contour analysis, and linear and non-linear heart rate variability were assessed before and following training. Overall, carotid arterial stiffness was reduced (p  0.05). This study demonstrates the effectiveness of interval training at improving arterial stiffness and autonomic function, however, the metabolic stress was not a mediator of this effect. In addition, these changes were also independent of improvements in aerobic capacity, which were only induced by training that involved a high metabolic stress

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 reendothelialization, 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.This work was supported by the British Heart Foundation, London, UK, and the Diabetes Research and Wellness Foundation, Portsmouth, UK