Evolution of magnetic surfboards and spin glass behavior in (Fe1-pGap)2TiO5

The unusual anisotropy of the spin glass (SG) transition in the pseudobrookite system Fe2TiO5has been interpreted as arising from an induced, van der Waals-like, interaction among magnetic clusters. Here we present susceptibility (χ) and specific heat data (C) for Fe2TiO5diluted with non-magnetic Ga, (Fe1-pGap)2TiO5, for disorder parameterp= 0, 0.11, and 0.42, and elastic neutron scattering data forp= 0.20. A uniform suppression ofTgis observed upon increasingp, along with a value ofχTgthat increases asTgdecreases, i.e.dχ(Tg)/dTg<0We also observeCT∝T2in the low temperature limit. The observed behavior places (Fe1-pGap)2TiO5in the category of a strongly geometrically frustrated SG.

Two-year quality of life after acute pulmonary embolism: results from the FOCUS study

Background/Introduction

No firm prospective evidence exists on the long-term course of disease-specific and generic quality of life (QoL) or their determinants in patients with acute pulmonary embolism (PE). Reliable data on this topic is essential for early identification of patients at risk of deviating from the expected course and prevention of clinical events affecting QoL recovery after PE.

Purpose

We examined the two-year course of QoL and the impact of events occurring after the acute phase of PE in patients from the prospective multicentre FOllow-up after aCUte pulmonary emboliSm (FOCUS) study.

Methods

All patients with complete QoL assessment at 3, 12 and 24 months (N=462) were included in the analysis of the two-year course of QoL; all patients with QoL assessment at 12 months, 24 months, or both (N=740) contributed to a multivariable linear mixed-effects regression for the investigation of determinants of long-term QoL. Disease-specific QoL was assessed with the Pulmonary Embolism Quality of Life (PEmb-QoL) instrument (global score: 0 = best, 100 = worst QoL), generic health-related QoL with the Euro Quality of life group (EuroQol) five-dimensions utility index (EQ-5D-5L; 0 = worst, 1 = best QoL) and the EuroQol visual analogue scale (0 = worst, 100 = best QoL). Incident events (recurrent PE, bleeding, stroke, new cancer diagnosis, and re-hospitalization) were modelled as time-varying covariates from discharge to month 12 and from month 12 to month 24.

Results

Among 462 patients with complete QoL assessment [200 (43.3%) women, median age 61.5 (IQR: 49–72) years, high-risk PE 15/462 (3.2%)], the median (IQR) PEmb-QoL score at 3, 12, and 24 months was 20 (9–36), 14 (5–30) and 13 (5–28), with a similar trend across all sub-dimensions (Figure 1); the mean (95% CI) EQ-5D-5L utility index 0.86 (0.84–0.88), 0.88 (0.87–0.90) and 0.87 (0.85–0.89); the mean (95% CI) EuroQoL visual analogue scale 74.2 (72.5–75.9), 76.8 (75.2–78.4) and 76.3 (74.6–78.0). Upon multivariable analysis in 740 patients with QoL data at 12 or 24 months, QoL according to all three scales was worse in women, patients of older age, with cardiopulmonary disease, with higher BMI, and in smokers, but did not change significantly at 24 vs 12 months. Incident PE recurrence or stroke did not considerably affect any of the QoL dimensions, whereas re-hospitalization for any cause worsened disease-specific QoL, a new cancer diagnosis worsened both scales of generic QoL, and bleeding worsened generic QoL as assessed by the Visual Analogue Scale (Table 1).

Conclusion

Generic and disease-specific QoL after PE improved in the first year and then plateaued in the second year. Disease-specific QoL was adversely affected by re-hospitalization for any cause but was robust to new cancer diagnosis and bleedings, which instead worsened generic QoL. These findings may support long-term management of patients with PE and contribute to design and interpretation of interventional studies.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Bayer Health Care

Effects of targeted therapy on blood gas analysis in pulmonary arterial hypertension – a retrospective analysis

Background

In pulmonary arterial hypertension (PAH), there is an excessive respiratory drive, which leads to inefficient ventilation with subsequent hypocapnia. Changes in blood gas analysis (BGA) may correlate with symptom severity and outcome. Data on impact of targeted PAH therapy on BGA are scarce and it remains unclear if these values can be used for risk stratification purposes.

Purpose

To assess capillary BGA in PAH at diagnosis and to evaluate the effect of targeted therapy on classical and calculated BGA parameters.

Methods

147 patients (62.3±17.1 years; female/male ratio: 66.7/33.3%) with newly diagnosed PAH were treated with targeted PAH therapy. 12-month follow-up included assessment of capillary blood gases and clinical variables. Patients underwent repeat RHC after 15.9±15.5 months.

Results

At diagnosis, both pcO2 (66.8±1.3 mmHg) and pcCO2 (32.7±0.5 mmHg) were slightly reduced. At 12-month follow-up, pcCO2 increased significantly to values within normal range (35.3±0.4 mmHg), while pcO2 showed no significant changes. After using the formula to calculate standard pcO2, baseline values were even lower, but there were significant improvements at 12-month follow-up, also reaching normal values. Changes in pcCO2 and standard pcO2 at diagnosis correlated with hemodynamics and survival at follow-up. Repeated RHC demonstrated significant reductions in mean PAP (48.9±1.2 to 39.9±1.0 mmHg; −18.4%), and PVR (11.3±0.7 to 6.2±0.3 WU; −45.1%), and an increase in cardiac index (2.1±0.04 to 2.6±0.1 ml/min/m2; +23.8%) (all p&lt;0.05). Hemodynamic improvements correlated with improved clinical parameters, including 6-minute walking distance (344±9 to 393±9 m), NTproBNP serum levels (2.163±219 to 772±84 ng/l, both p&lt;0.05) and WHO-FC at 12 months, resulting in improved risk status.

Conclusions

Targeted PAH therapy leads to significantly improved cardiopulmonary hemodynamics with subsequent increase in pcCO2, presumably due to less hyperventilation. Changes in pcCO2 and standard pcO2 (but not pcO2) correlate with hemodynamics and survival, potentially serving as non-invasive parameters for risk assessment and therapeutic response. The discrepancy between pcO2 and standard pcO2 at diagnosis suggests that pcO2 is upregulated by the hyperventilatory state. Standard pcO2 represents an easy-to-calculate parameter that can help more accurately identify PAH patients requiring O2 therapy in addition to targeted therapy. Further studies are needed in this context.

Funding Acknowledgement

Type of funding sources: None.

Signs of chronic thromboembolic pulmonary hypertension in acute pulmonary embolism: results from the FOCUS study

Background/Introduction

Chronic thromboembolic pulmonary hypertension (CTEPH) is considered to be a late complication of acute pulmonary embolism (PE). However, up to one third of CTEPH patients do not report prior symptomatic venous thromboembolism (VTE). Furthermore, a substantial proportion of patients presenting with an acute PE event may exhibit radiological signs of chronicity at baseline computed tomography pulmonary angiography (CTPA).

Purpose

To determine the prevalence of baseline radiological parameters indicating chronic thrombosis or pulmonary hypertension, and ultimately pre-existing CTEPH, among patients with acute PE enrolled in the prospective multicentre Follow-Up after Acute Pulmonary Embolism (FOCUS) cohort study.

Methods

Patients with acute symptomatic PE and absence of a known history of CTEPH, enrolled at two large FOCUS centres, were included. The assessment of index CTPA scans was conducted by two independent expert radiologists who were unaware of the clinical characteristics and the follow-up data of the patients. CTPA parameters indicating chronicity were prespecified on the basis of recently proposed criteria in the literature. A third independent expert radiologist provided an assessment in case of disagreement between the first two. Baseline radiological data were prospectively validated with the aid of two-year prospective clinical follow-up data focusing on CTEPH and the post-PE syndrome (co-primary outcomes of the FOCUS study).

Results

A total of 303 patients (median age: 63 years, 44.6% women) were included. In &gt;95% of the patients, the expert radiologists could confirm signs of acute PE at baseline CTPA. Radiological signs of chronic thrombi or pulmonary hypertension at baseline were detected in 46 (15.2%) patients. In 8 patients, the expert radiologists agreed on the presence of pre-existing CTEPH based on their interpretation of the overall radiological pattern. During follow-up, five (1.7%; 95% CI 0.7–3.8%) of 303 patients were diagnosed with CTEPH, over a median time of 95 days after baseline. Four of them were among the 8 patients in whom the radiological experts suspected pre-existing CTEPH at baseline, and among the 46 patients in whom CTPA findings suggesting chronic thrombi or chronic pulmonary hypertension were present at baseline. The use of the predefined individual parameters of chronicity from the literature also helped identifying patients with chronic disease, and could be used as a tool for screening acute PE patients for pre-existing CTEPH.

Conclusion

A substantial proportion of patients who are diagnosed with CTEPH during follow-up after acute PE may already have pre-existing CTEPH at the time of the index event. An intensified follow-up programme and focussed screening for CTEPH should be considered in patients with signs of chronicity at baseline CTPA.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Bayer Health Care

Inactivation of catalytic and non-catalytic PI3 kinase gamma functions enhances hypoxia-induced pulmonary hypertension in mice

Rationale

Pulmonary hypertension (PH) is a pulmonary vascular disease characterised by chronically elevated pulmonary arterial mean pressure, increased pulmonary vascular resistance and right ventricular (RV) dysfunction and hypertrophy. The pathogenesis includes vasoconstriction of pulmonary vessels and pulmonary vascular remodelling. Phosphatidylinositol 3'-kinase γ (PI3Kγ) is highly expressed in leukocytes, endothelial cells (EC) and cardiomyocytes, which are involved in the pathogenesis of PH. The catalytic function of PI3Kγ has been shown to be associated with numerous processes that are potentially important for both vascular remodelling and maladaptive cardiac hypertrophy, including leukocyte recruitment and endothelial cell proliferation and survival. However, inhibition of non-catalytic PI3Kγ function results in reduced nitric oxide (NO) production by endothelial NO synthase (eNOS), which may lead to increased vascular resistance. Therefore, the aim of our study was to investigate the role of both catalytic and non-catalytic PI3Kγ functions in the pathogenesis of PH.

Methods

The importance of PI3Kγ in the pathogenesis of PH was analysed in vivo using the hypoxia-induced mouse model of PH (21 days at 10% O2 hypoxia (HOX)). PI3Kγ knockout mice (PI3Kγ−/−), as well as mice expressing a catalytically inactive form of PI3Kγ (PI3KγKD/KD) were investigated. To specifically inhibit the non-catalytic function of PI3Kγ, C57BL/6N mice were treated with a blocking peptide via intratracheal instillation and studied in the same model. Subsequently, systolic right ventricular pressure (RVSP) was measured using a Millar pressure catheter inserted via the jugular vein. In vitro, western blotting was used to investigate the phosphorylation of eNOS (Ser1177) in pulmonary ECs from wild type (WT), PI3Kγ−/− and PI3KγKD/KD mice.

Results

PI3Kγ−/− mice showed significantly increased RVSP after three weeks of hypoxia compared with WT controls (HOX WT 34.16±3.47mmHg vs. HOX PI3Kγ−/− 37.04±2.43mmHg; p=0.005; n≥7). A significant increase in RVSP was also detected in PI3KγKD/KD and blocking peptide-treated mice (HOX WT 34.67±2.02mmHg vs. HOX PI3KγKD/KD 37.95±1.39mmHg; p=0.023; n≥5 and HOX vehicle 34.19±2.74mmHg vs. HOX blocking peptide 37.61±2.46mmHg; p=0.011; n≥9). Heart rate, as well as systemic blood pressure, remained unchanged. Under normoxic conditions, no difference in RVSP between the groups could be measured. Interestingly, western blot detected reduced phosphorylation of eNOS after stimulation with fetal calf serum in PI3Kγ−/− ECs compared to WT and PI3KγKD/KD.

Conclusion

These results show that blunting of both catalytic and non-catalytic functions of PI3Kγ in vivo do not prevent the pathogenesis of PH, but conversely enhance hypoxia-induced elevation of RVSP. In this context, reduced phosphorylation of eNOS may play a crucial role, leading to increased vasoconstriction. Additional studies are required to evaluate the underlying mechanisms in detail.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): DFG Deutsche Forschungsgemeinschaft

Lack of PI 3-kinase isoform p110alpha impairs SMC differentiation and proliferation and promotes aortic aneurysm formation

Background

Proliferation and phenotypic modulation of vascular smooth muscle cells (SMCs) significantly contribute to the functionality of the aortic wall. Dysregulation of underlying signal transduction pathways impairs the vessel wall structure and promote the development and progression of abdominal aortic aneurysms (AAA). The PI 3-kinase (PI3K) isoform p110α is activated downstream of receptor tyrosine kinases (RTKs) and represents the most relevant PI3K isoform in SMCs.

Aim

This project follows the hypothesis that p110α deficiency impairs proliferation and phenotypic modulation of SMCs as well as the structure of the extracellular matrix (ECM) and therefore promotes the development and progression of AAA. It was investigated how p110α deficiency affects the plasticity of SMCs, the production and structure of ECM components, and the formation of AAA.

Methods and results

Western blot analyses showed that SMCs isolated from smooth muscle specific p110α−/− (sm-p110α−/−) mice were characterized by decreased expression of the differentiation markers sm-α-actin, calponin and sm-MHC. Mechanistically, phosphorylation of key modulators of the SMC phenotype – AKT1, AKT2, FOXO1, -3 and -4 as well as GSK3β – was impaired in p110α−/− SMCs after RTK stimulation. These findings indicate that phenotypic modulation of p110α−/− SMCs is restricted. In addition, protein expression of elastin and fibrillin was reduced in p110α−/− SMCs. In silico analysis (MatLab macro CT-FIRE and Curvalign) of the ECM produced by SMCs in vitro revealed a significantly reduced elastin fiber length and width in p110α−/− SMCs compared to fibers produced by WT SMCs (p&lt;0.05). Consistently, aortas from sm-p110α−/− mice showed a significantly higher number of elastic fiber breaks specifically in the thoracic section than WT controls (289±31 mmm–2 versus 190±9 mmm–2, n=5, p=0.015). Aortic aneurysms in sm-p110α−/− mice and wild-type littermates were analyzed using the established porcine pancreatic elastase (PPE) model. PPE was perfused into the infrarenal aorta to induce AAA formation. Ultrasound examination of the aorta revealed an enlarged aortic diameter in all PPE-treated mice. However, the increase in aortic diameter in sm-p110α−/− mice (70.16±10.82% mm, n=9) was significant more pronounced compared to wild-type animals (42.44±5.99%, n=10) (p&lt;0.05). Three days after PPE perfusion, the number of elastic fiber breaks was significantly increased, and amount of proliferating SMCs were decreased in the infrarenal aorta of sm-p110α−/− mice compared to WT controls.

Conclusion

p110α deficiency in SMCs impairs aortic wall structure and promotes the development and progression of aortic aneurysms. Mechanistically, p110α activity maintains a differentiated SMC phenotype as well as the expression and assembly of ECM components. These data identify p110α signaling as a modifiable target for preventive and therapeutic strategies for aortic aneurysms.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft

Active and passive defects in tetragonal tungsten bronze relaxor ferroelectrics

Tetragonal tungsten bronze (TTB) based oxides constitute a large family of dielectric materials which are known to exhibit complex distortions producing incommensurately modulated superstructures as well as significant local deviations from their average symmetry. The local deviations produce diffuse scattering in diffraction experiments. The structure as well as the charge dynamics of these materials are anticipated to be sensitive to defects, such as cation or oxygen vacancies. In this work, in an effort to understand how the structural and charge dynamical properties respond to these two types of vacancy defects, we have performed measurements of dielectric susceptibilities and single crystal diffraction experiments of two types of TTB materials with both 'filled' (Ba₂NdFeNb₄O₁₅and Ba₂PrFeNb₄O₁₅) and 'unfilled' (Sr_0.5Ba_0.5Nb₂O₆) cation sublattices. We also perform these measurements before and after oxygen annealing, which alters the oxygen vacancy concentrations. Surprisingly, we find that many of the diffuse scattering features that are present in the unfilled structure are also present in the filled structure, suggesting that the random fields and disorder that are characteristic of the unfilled structure are not responsible for many of the local structural features that are reflected in the diffuse scattering. Oxygen annealing clearly affected both color and dielectric properties, consistent with a diminishment of the oxygen vacancy concentration, but had little effect on observed diffuse patterns.

Selective inhibition of the PI3K isoform p110alpha using BYL719 protects against tyrosine kinase-mediated processes in PASMCs and reduces experimental pulmonary hypertension in mice and rats

Rationale

Pulmonary arterial hypertension (PAH) is a vascular disease characterized by chronic increases in pulmonary vascular resistance (PVR), pulmonary arterial pressure (PAP), and right ventricular (RV) hypertrophy. Increased activation of receptor tyrosine kinase (RTK) -mediated signaling pathways leads to increased proliferation and migration of pulmonary smooth vascular muscle cells (PASMCs) which promote vascular remodeling processes. We identified the catalytic subunit p110alpha of phosphatidylinositol-3-kinase as a key enzyme for these processes and showed that both genetic ablation of p110alpha in SMCs and pharmacological inhibition can prevent experimental PH. Here, the effects of the orally bioavailable p110alpha selective PI3K inhibitor BYL719 on the RTK-mediated proliferation and chemotaxis of PASMCs, as well as the effects in the hypoxia-induced mouse and in the Sugen / hypoxia (SuHx) -induced rat model of PH were investigated.

Methods

Human and murine PASMCs were pretreated with different concentrations of BYL719 and stimulated with a mixture of growth factors (PDGF [30ng/ml], EGF [0,5ng/ml], bFGF [2ng/ml], insulin [0,5ng/ml], and FBS [5%]). Proliferation was investigated using a BrdU incorporation ELISA assay (Roche). Chemotaxis was quantified using modified Boyden chambers.

Male BL/6 mice were subjected to hypoxia (10% O2) for 21 days. Treatment with BYL719 (or vehicle) was carried out via daily gavage of 50mg/kg bodyweight.

In addition, a therapeutic approach was investigated using male Sprague Dawley rats in the SuHx model, which were treated with BYL719 (20 mg / kg body weight) or vehicle for 2 weeks after a three-week hypoxia phase. The RV pressure (RVSP) was measured using a Millar® or liquid-filled catheter. The RV hypertrophy is shown as the quotient of the weights of the RV to the LV + septum (RV / (LV + S)).

Results

Growth factor-induced proliferation and chemotaxis of the PASMCs were significantly and concentration-dependently inhibited by BYL719. The exposure to hypoxia led to an increase of the RVSP (24.5±0.95 to 35.2±1.28 mmHg) and the development of right ventricular hypertrophy (RV / LV + S 0.24±0.01 to 0.37±0.073), which was significantly reduced in the BYL719 treated group (RVSP 31.4±0.53 mmHg; RV / LV + S 0.31±0.01) (p&lt;0.05). In addition, SuHx led to a robust increase of the RVSP (129.2±5.4 mmHg) and pronounced RV hypertrophy (RV / (LV + S): 0.86±0.04), which were significantly reduced by the therapeutic BYL719 treatment (102.0±6.1 mmHg or 0.64±0.03).

Conclusion

These results show that inhibition of p110alpha using the BYL719 reduced growth factor-mediated pathological processes in PASMCs in vitro, as well as hypoxia-induced (mouse) and already established SuHx-induced PH (rat). Thus, the inhibition of p110a using BYL719 represents a promising approach for the treatment of PAH.

Funding Acknowledgement

Type of funding sources: None.

Changes in cMRI parameters following a switch to riociguat from phosphodiesterase type 5 inhibitors (PDE5i) in patients with pulmonary arterial hypertension: a REPLACE substudy

Background

The REPLACE study investigated the effect of switching to riociguat (RIO) in patients with pulmonary arterial hypertension receiving PDE5i but still at intermediate risk. The centrally adjudicated composite primary endpoint was clinical improvement in the absence of clinical worsening, where clinical improvement was defined as meeting at least two of the following criteria: 6-minute walk distance (6MWD), increase by ≥10% or ≥30 m from baseline (BL) to Wk 24; World Health Organization functional class (WHO FC) I or II at Wk 24; or N-terminal prohormone of brain natriuretic peptide reduction of ≥30% from BL to Wk 24. Twice as many patients switching to RIO (45/111, 41%) met the primary endpoint compared with those remaining on PDE5i (23/113, 20%); odds ratio (OR): 2.78 (95% confidence interval [CI] 1.53–5.06); p=0.0007.

Purpose

Assess changes in right and left ventricular (RV; LV) function using cardiac magnetic resonance imaging (cMRI) in a subgroup of patients participating in REPLACE.

Methods

REPLACE was a randomised, open-label, 24-week, Phase 4 study (NCT02891850). Patients in WHO FC III, with 6MWD 165–440 m, were randomised to switch to RIO 2.5 mg–max tid or remain on PDE5i. Background endothelin receptor antagonist therapy was permitted in both arms.

cMRI was performed on a subset of patients from the full analysis set as an exploratory substudy. The following parameters were measured at BL and Wk 24: RV and LV end-diastolic and end-systolic volumes (RVEDV; RVESV; LVEDV; LVESV), RV stroke volume and stroke volume index (RVSV; RVSVI), LV stroke volume (LVSV), RV ejection fraction (RVEF), and pericardial effusion.

Results

Twenty-seven patients participated in the cMRI substudy. This comprised 11/111 (10%) patients in the RIO arm (mean [standard deviation {SD}] 40.0 [12.4] years), and 16/113 (14%) patients (mean 44.5 [17.6] years) in the PDE5i arm. Like the main population, the treatment response in the cMRI subpopulation favoured RIO versus PDE5i (OR: 6.11 [95% CI 0.90–41.60]). From BL to Wk 24, RVEDV and RVESV decreased in the RIO treatment arm but increased in the PDE5i treatment arm (Table 1). Similar, but less pronounced, changes were observed for the left ventricle (LVESV, LVEDV). RVSV and RVEF levels were close to normal at BL and did not increase in either arm at Wk 24 (Table 1). Pericardial effusion, which was present in 5 patients in each group at BL, decreased in 1 patient in the RIO arm and no patients in the PDE5i arm.

Conclusions

Decreases in RVEDV and RVESV suggest improvements in cardiac function in the RIO arm compared with the PDE5i arm. Values for RVEF and RVSVI were close to normal at BL and did not change at Wk 24. Improvements in cMRI parameters were in line with the clinical improvement observed in patients switching to RIO in the overall population.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): The REPLACE study was co-funded by Bayer AG (Berlin, Germany) and Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc. (Kenilworth, NJ, USA)

PI 3-kinase isoform PI3Kalpha controls smooth muscle cell functionality and protects against aortic aneurysm formation

Background

Class I PI 3-kinase isoform PI3Kα is a lipid kinase and signals downstream of receptor tyrosine kinases. Smooth muscle cells (SMCs) lacking PI3Kα are characterized by impaired proliferation, migration and survival. Mice, harbouring a smooth muscle specific PI3Kα deficiency (SM-PI3Kα−/−), display reduced vascular wall thickness and impaired vascular remodeling in response to vessel injury. We hypothesize that SM-PI3Kα−/− mice are prone to aortic aneurysm (AA) formation due to impaired SMC functions. Herein, we investigated, how PI3Kα-dependent signaling in SMCs affect aortic aneurysm (AA) formation, aortic wall structure, and expression of extracellular matrix (ECM) components.

Methods and results

AA formation in SM-PI3Kα−/− mice and wild-type littermates was examined by means of the “porcine pancreatic elastase” (PPE) AA model. PPE was infused into the infrarenal aorta to induce AA formation. Ultrasound examination revealed a significantly increased aortic diameter in SM-PI3Kα−/− mice (1.22±0.12 mm) compared to wild-type animals (0.96±0.02 mm, p=0.014). These data indicate a protective function of SM-PI3Kα in AA formation. In addition, the media thickness in the abdominal aorta was significantly reduced in SM-PI3Kα−/− mice (29.0±3.1 vs. 42.5±4.1 μm). Ultrastructural analysis of aortic wall morphology in SM-PI3Kα−/−mice using transmission electron microscopy (TEM) showed a deranged tunica media with detached SMCs and increased apoptotic cell death. Consequently, SM-PI3Kα deficiency significantly diminished responsiveness of aortic rings to vasodilator acetylcholine and NO-donor nitroglycerin, further indicating impaired aortic wall structure. Western blots demonstrated a reduced elastin and fibrillin expression in SMCs from SM-PI3Kα−/− mice. Furthermore, immunofluorescence stainings of PI3Kα−/− and wild-type SMCs, cultured for seven days under 10% fetal calf serum containing DMEM medium, showed significantly disturbed structures of elastin-, fibrillin-1- and collagen-1-fibers. These data indicate that PI3Kα signaling contributes to elastic fiber homeostasis thus affecting SMC phenotypic modulation. Immunoblots demonstrated that PDGF and insulin induced phosphorylation and inactivation of key regulators of SMC differentiation and dedifferentiation including FoxO1, FoxO3a, Foxo4, and GSK3b, respectively, were reduced or even abrogated in PI3Kα−/− SMCs.

Conclusion

These data show that deficiency of PI3Kα in SMCs promotes the formation and progression of AA. Causative is a deranged aortic structure of SM-PI3Kα−/− aortae which can likely be attributed to an impaired production of elastic fiber components by PI3Kα−/− SMCs.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft

Two-dimensional overdamped fluctuations of the soft perovskite lattice in CsPbBr3

Lead halide perovskites exhibit structural instabilities and large atomic fluctuations thought to impact their optical and thermal properties, yet detailed structural and temporal correlations of their atomic motions remain poorly understood. Here, these correlations are resolved in CsPbBr₃ crystals using momentum-resolved neutron and X-ray scattering measurements as a function of temperature, complemented with first-principles simulations. We uncover a striking network of diffuse scattering rods, arising from the liquid-like damping of low-energy Br-dominated phonons, reproduced in our simulations of the anharmonic phonon self-energy. These overdamped modes cover a continuum of wave vectors along the edges of the cubic Brillouin zone, corresponding to two-dimensional sheets of correlated rotations in real space, and could represent precursors to proposed two-dimensional polarons. Further, these motions directly impact the electronic gap edge states, linking soft anharmonic lattice dynamics and optoelectronic properties. These results provide insights into the highly unusual atomic dynamics of halide perovskites, relevant to further optimization of their optical and thermal properties.

Large intrinsic anomalous Hall effect in SrIrO3 induced by magnetic proximity effect

The anomalous Hall effect (AHE) is an intriguing transport phenomenon occurring typically in ferromagnets as a consequence of broken time reversal symmetry and spin-orbit interaction. It can be caused by two microscopically distinct mechanisms, namely, by skew or side-jump scattering due to chiral features of the disorder scattering, or by an intrinsic contribution directly linked to the topological properties of the Bloch states. Here we show that the AHE can be artificially engineered in materials in which it is originally absent by combining the effects of symmetry breaking, spin orbit interaction and proximity-induced magnetism. In particular, we find a strikingly large AHE that emerges at the interface between a ferromagnetic manganite (La_0.7Sr_0.3MnO₃) and a semimetallic iridate (SrIrO₃). It is intrinsic and originates in the proximity-induced magnetism present in the narrow bands of strong spin-orbit coupling material SrIrO₃, which yields values of anomalous Hall conductivity and Hall angle as high as those observed in bulk transition-metal ferromagnets. These results demonstrate the interplay between correlated electron physics and topological phenomena at interfaces between 3d ferromagnets and strong spin-orbit coupling 5d oxides and trace an exciting path towards future topological spintronics at oxide interfaces.

Voluntary wheel running promotes improvements in biomarkers associated with neurogenic activity in adult male rats

In rodents, hippocampal neurogenesis and synaptogenesis phenomena are affected by exercise. However, the role of exercise parameters such as intensity, duration, and mode on molecular mechanisms involved in these processes has not been elucidated. In this study, we evaluated the effects of different intensities and modes of running on the expression of genes contributing to neuronal differentiation and synapse formation in the hippocampus of adult male rats. Adult male Wistar rats (n = 24) were randomly divided into control, low-intensity running (LIR), high-intensity running (HIR), and the voluntary wheel running (WR) conditions. Changes in the expression of microRNA-124 (miR-124), microRNA-132 (miR-132), and their respective targets, were analyzed using quantitative RT-PCR and Western blotting techniques. Our results showed that WR compared to treadmill running increased miR-124 and miR-132 expression, while reducing the expression of their respective targets, glucocorticoid receptor (GR), SRY-Box 9 (SOX9), and GTP-activated protein P250 (P250GAP). Differences in expression levels were statistically significant (ps < 0.05), except for the expression of GR in HIR (P = 0.09). Moreover, the expression level of gene coding for the transcription factor cAMP-response element binding protein (CREB) was significantly higher in the WR group compared to the treadmill running groups (P = 0.001). Western blotting techniques indicated that the level of the CREB protein was higher in WR compared to the other groups qualitatively. These findings demonstrated a more dramatic effect for voluntary running on biomarkers that are associated with stimulating neurogenesis and synapse formation in the hippocampus of male rats compared with forced treadmill running. In addition, greater positive effects were observed for lower-intensity treadmill running as compared with high-intensity running.

Intertwined density waves in a metallic nickelate

Nickelates are a rich class of materials, ranging from insulating magnets to superconductors. But for stoichiometric materials, insulating behavior is the norm, as for most late transition metal oxides. Notable exceptions are the 3D perovskite LaNiO₃, an unconventional paramagnetic metal, and the layered Ruddlesden-Popper phases R₄Ni₃O₁₀, (R = La, Pr, Nd). The latter are particularly intriguing because they exhibit an unusual metal-to-metal transition. Here, we demonstrate that this transition results from an incommensurate density wave with both charge and magnetic character that lies closer in its behavior to the metallic density wave seen in chromium metal than the insulating stripes typically found in single-layer nickelates like La_2-xSr_xNiO₄. We identify these intertwined density waves as being Fermi surface-driven, revealing a novel ordering mechanism in this nickelate that reflects a coupling among charge, spin, and lattice degrees of freedom that differs not only from the single-layer materials, but from the 3D perovskites as well.

Layered Ruddlesden-Popper structure nickelates R₄Ni₃O₁₀ (R = La,Pr) show an unusual metal-to-metal transition, but its origin has remained elusive for more than two decades. Here, the authors show that this transition results from intertwined density waves that arise from a coupling between charge and spin degrees of freedom

Haematopoietic PI3-kinase delta deficiency profoundly impairs regulatory T-cell biology and thereby protection against atherosclerosis

Introduction and purpose

Atherosclerosis is a chronic inflammatory disease of arteries, critically involving leukocytes like macrophages as well as T and B lymphocytes. Macrophages are major drivers of disease through the ingestion of lipoproteins, foam cell formation, and secretion of inflammatory mediators. Although macrophages outnumber other leukocytes in atherosclerotic plaques, T and B cells can shape the course of disease by promoting or mitigating inflammatory responses. Leukocytes highly express the phosphoinositide 3-kinase isoform delta (PI3Kd), exerting a key role in the regulation of immune responses including activation, proliferation, differentiation, and effector functions. Therefore, PI3Kd represents a promising target for the modulation of inflammatory diseases. Consequently, we aimed to analyse the role of PI3Kd in leukocytes during atherogenesis.

Methods and results

To investigate the role of PI3Kd in atherosclerosis, bone marrow from PI3Kd−/− or PI3Kd+/+ mice was transplanted into LDLR−/− mice. After a 6-weeks-challenge by high fat diet, PI3Kd−/− recipient LDLR−/− mice displayed profoundly impaired CD4+ and CD8+ T-cell numbers, CD4+ T-cell activation, CD4+ effector T-cell differentiation, and proatherogenic CD4+ T-helper (Th) 1 responses in para-aortic lymph nodes and spleen compared with PI3Kd+/+ transplanted controls. Surprisingly, the net effect of PI3Kd deficiency was a substantial increase of aortic inflammation and atherosclerosis in LDLR−/− mice. Whereas plaque content and functions of macrophages including foam cell formation, efferocytosis, and cytokine secretion remained unaffected, haematopoietic PI3Kd ablation strongly reduced mature B cells and serum immunoglobulins in LDLR−/− mice. Importantly, PI3Kd deficiency severely impaired numbers and immunosuppressive functions of regulatory CD4+ T cells (Tregs) in spleen, para-aortic lymph nodes, and plaques of LDLR−/− mice. Consequently, adoptive transfer of PI3Kd+/+ Tregs fully constrained the plaque burden in PI3Kd−/− transplanted LDLR−/− mice without affecting B-cell numbers and serum immunoglobulins, whereas adoptively transferred PI3Kd−/− Tregs were unable to relieve atherosclerosis progression.

Conclusions

Here, we demonstrate that PI3Kd plays a crucial role in Tregs, Th1 cells, and B cells during atherogenesis. Lack of PI3Kd signalling specifically in atheroprotective Treg responses outplays its impact on proatherogenic Th1 and B-cell responses, thus leading to aggravated atherosclerosis. Hence, PI3Kd is a key regulator of Treg biology and thereby protects against atherosclerosis.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Marga and Walter Boll Foundation

Lack of PI 3-kinase isoform p110alpha in smooth muscle cells impairs aortic wall homoeostasis and thus promotes aortic aneurysm formation

Background

In smooth muscle cells (SMCs), the PI 3-kinase isoform p110α mediates receptor tyrosine kinase dependent proliferation, chemotaxis and cell survival. Since mice, harbouring a smooth muscle specific p110α deficiency (SM-p110α−/−), display reduced vascular wall thickness, we hypothesized that SM-p110α−/− mice might be prone to aortic aneurysm (AA) formation. The pathogenesis of AA is characterized by increased dedifferentiation of SMCs, extracellular matrix (ECM) degeneration and inflammation in the aortic wall. Herein, we investigated how p110α-dependent signal transduction in SMCs affects these processes.

Methods and results

We examined AA formation in SM-p110α−/− mice and wild-type littermates using the “porcine pancreatic elastase” (PPE) AA model. PPE was infused into the infrarenal aorta to induce AA formation. Ultrasound examination of the aorta revealed an enlarged aortic diameter in all PPE-treated mice. The aortic diameter in SM-p110α−/− mice (0.46±0.12 mm) was significantly increased compared to wild-type animals (0.18±0.03 mm, p&lt;0.01). These data indicate a protective function of p110α in AA formation. Immunocytochemical examination of the tunica media of PPE-perfused SM-p110α−/− mice revealed significantly increased infiltration of CD45+ leukocytes. In particular, the number of MOMA-2+ monocytes / macrophages in the vessel wall was significantly increased indicating elevated inflammation of the aortic wall during AA progression in comparison to wild-type control mice. Ultrastructural analysis of aortic wall morphology in SM-p110α−/− mice using transmission electron microscopy (TEM) showed a deranged tunica media and increased apoptotic cell death. In addition, the media thickness in the abdominal aorta was significantly reduced in SM-p110α−/− mice (29.0±3.1 μm vs. 42.5±4.1 μm). Western blots demonstrated a reduced elastin and fibrillin expression in SMCs from SM-p110α−/− mice. p110α−/− SMCs showed significantly reduced expression of differentiation markers SM-α-actin and SM-MHC. In addition, aortic p110α-deficient SMCs were significantly impaired in their ability to proliferate and migrate. These findings indicate that p110α−/− SMCs are neither differentiated nor dedifferentiated and have therefore largely lost their plasticity. Consequently, p110α deficiency significantly diminished responsiveness of aortic rings to vasodilator acetylcholine and NO-donor nitroglycerin, further indicating impaired contractility of SMCs. Mechanistically, we demonstrated that PDGF and insulin induced phosphorylation and inactivation of key regulators of SMC differentiation and dedifferentiation, Foxo4 and GSK3b, respectively, were abrogated in p110α−/− SMCs.

Conclusion

These data show that deficiency of p110α in SMCs promotes the formation and progression of AA. Causative are impaired SMC plasticity and ECM homeostasis as well as inflammatory processes in the vascular wall.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft (DFG)

Effect of macitentan on left ventricular (LV) function in pulmonary arterial hypertension (PAH): results from REPAIR

Introduction

PAH impacts right ventricular (RV) structure and function but also leads to changes in the LV due to RV/LV interaction and underfilling. REPAIR, the first PAH study to use a primary endpoint assessed by cardiac MRI (cMRI), reported that RV stroke volume (RVSV) increased by 12 mL and pulmonary vascular resistance (PVR) decreased by 38% from baseline (BL) to Week 26 with macitentan.

Purpose

To assess the effect of macitentan on LV function in patients with PAH.

Methods

REPAIR (NCT02310672) was a 52-week, multicentre, open-label, single-arm, phase 4 study assessing the effect of macitentan primarily on RV structure and function, determined by cMRI and right heart catheterisation. Macitentan 10 mg was initiated in treatment-naïve patients, in patients receiving stable background phosphodiesterase type-5 inhibitor (PDE5i) at BL, or in initial combination with PDE5i. Exploratory LV endpoints were assessed by cMRI at Weeks 26 and 52. Safety was assessed up to end of study treatment +30 days in all patients who received ≥1 dose of macitentan (N=87). Patients with BL and Week 26 assessments for both PVR and RVSV were included in the modified Full Analysis Set (mFAS; N=71).

Results

In the mFAS, 57 (80%) patients were female. At BL, median age was 45 years; median (Q1, Q3) six-minute walk distance was 395 (323, 483) m; 48%/51% of patients were WHO functional class II/III; 59% had idiopathic PAH. Compared to BL, at Weeks 26 and 52 there were significant changes in LV cMRI parameters (table). The most common AEs were peripheral oedema (22%), headache (21%) and dizziness (14%).

Conclusions

Macitentan led to improvements in LV mass, volume and function, including clinically-relevant increases in LV stroke volume, at both 26 and 52 weeks in patients with PAH. Safety was consistent with other macitentan clinical trial data.

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): Actelion Pharmaceuticals Ltd

The unexpected role of PI3-kinase gamma in pulmonary hypertension

Introduction

Pulmonary hypertension (PH) is a pulmonary vascular disease that is associated with unacceptably high morbidity and mortality. PH is characterized by chronically increased pulmonary arterial pressure, increased pulmonary vascular resistance and right ventricular (RV) dysfunction and hypertrophy. Underlying mechanisms include increased proliferation and reduced apoptosis of both vascular smooth muscle cells (SMC) and endothelial cells (EC), as well as dysregulated immune responses. We have previously shown that class IA phosphatidylinositol-3-kinase (PI3K) isoforms, activated via receptor tyrosine kinases, are critically involved in the pathogenesis of PH. However, recent findings suggest that the class IB isoform PI3Kγ, which is activated downstream of G protein coupled receptors, is also important. It has been shown that PI3Kγ is involved in numerous processes that promote both vascular remodelling and maladaptive cardiac hypertrophy, including leukocyte recruitment, expression of proinflammatory chemokines and cytokines, as well as SMC and EC proliferation and survival. Therefore, the aim of our study was to investigate the role of PI3Kγ in the pathogenesis of PH.

Methods

The impact of PI3Kγ on the pathogenesis of PH was analysed in vivo using mice expressing a catalytically inactive form of PI3Kγ (PI3KγKD/KD) in the hypoxia-induced mouse model of PH. Mice were kept at 10%O2 (HOX) for 21 days or left under normoxic conditions (NOX). Subsequently, systolic right ventricular pressure (RVSP) was measured with a pressure catheter. RV hypertrophy was expressed as the ratio of RV weight to left ventricular + septum weight. Migration and proliferation of human pulmonary arterial SMC (hPASMC) as well as EC (hMVEC) were analysed using a PI3Kγ isoform-specific inhibitor (AS605240 [0.1; 0.3; 1μM]). Chemotaxis was determined by means of a modified Boyden chamber, and proliferation was quantified by a Bromodeoxyuridine (BrdU) incorporation assay.

Results

Whereas PI3Kγ inactivation had no effect on NOX animals, hypoxia led to increased RVSP and RV hypertrophy in WT animals (34.67±2.02 mmHg; 0.38±0.087) which were unexpectedly further increased in PI3KγKD/KD mice (37.67±1.3 mmHg, p=0.0104 vs. HOX WT; 0.47±0.06, p=0.0155 vs. HOX WT). Heart rate and systemic blood pressure remained unchanged. Inhibition of PI3Kγ by means of AS605240 did not affect proliferation of hPASMC and hMVEC, induced by multiple stimuli (FCS [10%], PDGF-BB [30ng/ml], or CXCL12 [100ng/ml], VEGF [50ng/ml]), respectively. However, FCS-induced migration of these cells was significantly reduced by AS605240 [0.3μM] (p&lt;0.05).

Conclusion

Contrary to our expectations, the results show that kinase inactivation of PI3Kγ was not able to attenuate the pathogenesis of PH, but surprisingly led to a significant increase without critically changing cellular responses of SMC and EC. Therefore, our results indicate an unexpected protective effect of PI3Kγ on PH.

Funding Acknowledgement

Type of funding source: None

Quality of life 3 and 12 months after acute pulmonary embolism: analysis of 617 patients from the prospective multicentre FOCUS study

Background

Few data are available on the long-term course and predictors of quality of life (QoL) after acute pulmonary embolism (PE).

Aims

To evaluate the kinetics and determinants of QoL at 3 and 12 months after acute PE.

Methods

The Follow-Up after acute pulmonary embolism (FOCUS) study prospectively followed consecutive adult patients with objectively diagnosed PE. For this analysis, we considered patients who completed the Pulmonary Embolism QoL (PEmb-QoL) Questionnaire at two predefined visits 3 and 12 months after PE. PEmb-QoL, studied as total score and in its six dimensions, ranges from 0% (best QoL) to 100% (worst QoL). We studied the course of PEmb-QoL and the impact of baseline characteristics using multivariable linear regression.

Results

In 617 included patients (44% women, median age 62 years), overall QoL improved from 3 to 12 months, with a decrease of the mean PEmb-QoL score from 25.3% to 21.5% (p-value &lt;0.001). Intra-individual correlation between PEmb-QoL score at 3 and 12 months was high; Figure A. The improvement was consistent across all PEmb-QoL dimensions; Figure B. Female sex, cardiopulmonary diseases, and higher body mass index were the main factors associated with a worse QoL; Table. Age and smoking affected QoL only at 12 months. The improvement in QoL was faster in patients without cardiopulmonary diseases (−4.2%; 95% CI: −5.2% to −3.1%), without previous VTE (−4.3%; −5.5% to −3.2%), and in non-smokers (−4.2%; −5.3% to −3.1%).

Conclusions

In a large cohort of patients with pulmonary embolism, we quantified the improvement of QoL between 3 and 12 months after diagnosis. We identified factors independently associated with lower QoL and slower recovery of QoL that may reflect special patient needs. These estimates may facilitate the planning and interpretation of clinical trials with QoL as a study outcome.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): University Medical Center of the Johannes Gutenberg University, Mainz, Germany; German Federal Ministry of Education and Research

Synthesis and characterization of bulk Nd1-x Sr x NiO2 and Nd1-x Sr x NiO3

The recent reports of superconductivity in Nd_1-x Sr _x NiO₂/SrTiO₃ heterostructures have reinvigorated interest in potential superconductivity of low-oxidation state nickelates. Synthesis of Ni¹⁺-containing compounds is notoriously difficult. In the current work, a combined sol-gel combustion and high-pressure annealing technique was employed to prepare polycrystalline perovskite Nd_1-x Sr _x NiO₃ (x = 0, 0.1, and 0.2). Metal nitrates and metal acetates were used as starting materials, and the latter were found to be superior to the former in terms of safety and reactivity. The Nd_1-x Sr _x NiO₃ compounds were subsequently reduced to Nd_1-x Sr _x NiO₂ using calcium hydride in a sealed, evacuated quartz tube. To understand the synthesis pathway, the evolution from NdNiO₃ to NdNiO₂ was monitored using in situ synchrotron x-ray diffraction during the reduction process. Electrical transport properties were consistent with an insulator-metal transition occurring between x = 0 and 0.1 for Nd_1-x Sr _x NiO₃. Superconductivity was not observed in our bulk samples of Nd_1-x Sr _x NiO₂. Neutron diffraction experiments at 3 and 300 K were performed on Nd_0.9Sr_0.1NiO₂, in which no magnetic Bragg reflections were observed, and the results of structural Rietveld refinement are provided.

Glycemic and Insulinemic Response to Two Doses of Resistant Starch Type 4: A Randomized Controlled Crossover Trial

Objectives

Resistant starches (RS) have beneficial effects on glucose and insulin responses in the postprandial period following carbohydrate (CHO) consumption. In comparison to resistant starch types 1–3, evidence regarding the effects of resistant starch type 4 (RS4) on metabolic responses is sparse. The primary aim of the current study was to determine whether the glycemic and insulinemic responses to a nutritional RS4 bar (RS4) were lower as compared to a puffed wheat bar (PWB), when provided at the standard testing amounts of 50 g available CHO, as well as at a lower dose of 30 g available CHO.

Methods

Apparently healthy adults (n = 15; 9 M/6F; 26.1 ± 4.8 yrs) participated in this randomized controlled crossover trial. All participants completed six sessions, consuming a dextrose beverage or nutrition bar at each session. Two doses of 50 g and 30 g of available CHO were tested using dextrose control beverages (50DEX; 30DEX), puffed wheat bars (50PWB; 30PWB) and RS4 bars (50RS4; 30RS4). Participants fasted for 10–12 hrs prior to each visit with a minimum 72hr washout between sessions. Whole blood glucose and plasma insulin were measured at baseline and 10, 20, 30, 60, 90, and 120 min post consumption. Primary outcomes were determined using mixed-effects models in GraphPad Prism 8.0.1.

Results

Glucose incremental area under the curve (iAUC) was not significantly different between the 50 g conditions (P = 0.054). Insulin iAUC was lower for the 50RS4 bar compared to the 50PWB (Mean ± SD; DEX: 3339 ± 2020, PWB: 3968 ± 2454, RS4: 2046 ± 928.7μIU/mL; P = 0.034), with no differences between 50PWB and 50DEX or 50RS4 and 50DEX (ps &gt; 0.05). Both 30 g bars had lower glucose iAUCs compared to 30DEX (ps &lt; 0.05), with no difference between bars (P &gt; 0.05). The 30RS4 bar elicited a lower insulin iAUC compared to 30PWB and 30DEX (DEX: 2400 ± 1689, PWB: 1855 ± 665.7, RS4: 1115 ± 832.2 μIU/mL; ps &lt; 0.05) with no difference between 30PWB and 30DEX (P &gt; 0.05).

Conclusions

Resistant starch type 4 elicited a reduced insulinemic response despite a similar glycemic response, at standard testing amounts of 50 g CHO, as compared to puffed wheat. This effect was also observed at the 30 g dose, thereby showing consistent results following consumption. Therefore, RS4 seems to improve insulin function in apparently healthy adults regardless of the amount of RS4 consumed.

Funding Sources

MGP Ingredient Inc.

Resistance training attenuates circulating FGF-21 and myostatin and improves insulin resistance in elderly men with and without type 2 diabetes mellitus: A randomised controlled clinical trial

Fibroblast growth factor 21 (FGF-21) and myostatin have been proposed to be potential therapeutic target for insulin resistance in age-related metabolic disorders including type 2 diabetes (T2D). Moreover, despite the potential metabolic effect of resistance training on insulin resistance, aging, and T2D; the effect of this type of exercise training on FGF-21 and myostatin in elderly men with and without T2D are unknown. Forty-four elderly men were assigned to either the RT training (RT; without T2D: 12, with TD2 = 10) or the control group (C; without T2D: 12, with TD2 = 10). The RT group performed 12-wk resistance training intervention, 3 days/wk, 10 repetitions with 70% 1RM. At the baseline, the elderly men with T2D had a higher FGF-21 (p = 0.002) and myostatin (p = 0.02) concentrations and lower muscle strength (p = 0.01) than the elderly men without T2D. RT resulted in significant decrease in FGF-21 and myostatin concentration and increase in muscle strength in both elderly men with and without T2D (P = 0.001, for all) as well as decrease in HOMA-IR in only elderly men without T2D (P = 0.001). There was no significant difference in the RT-induced FGF-21 reduction between elderly men with and without T2D (p = 0.77, p = 0.28, respectively), but, RT caused a larger reduction in circulating myostatin in elderly men without T2D than with T2D (P = 0.007). Taken together, our results demonstrated that 12 weeks of RT induced an overall significant reduction of FGF-21 and myostatin in elderly men with and without T2D; with higher reduction of myostatin in elderly men without T2D.

Pulmonary hypertension in HFpEF and HFrEF: Pathophysiology, diagnosis, treatment approaches

Pulmonary hypertension (PH) is a frequent hemodynamic condition that is highly prevalent in patients with heart failure and reduced (HFrEF) or preserved ejection fraction (HFpEF). Irrespective of left ventricular EF, the presence of PH and right ventricular (RV) dysfunction are highly relevant for morbidity and mortality in patients with heart failure. While elevated left-sided filling pressures and functional mitral regurgitation primarily lead to post-capillary PH, current guidelines and recommendations distinguish between isolated post-capillary PH (IpcPH) and combined post- and pre-capillary PH (CpcPH), the latter being defined by a pulmonary vascular resistance (PVR) of ≥3 Wood units. Here, we describe the pathophysiology and clinical relevance of these distinct entities, and report on the diagnostic work-up including remote pulmonary artery pressure (PAP) monitoring. Furthermore, we highlight strategies to manage PH and improve RV function in heart failure, which may include optimized management of HFrEF and HFpEF (medical and interventional), sufficient volume control, catheter-based mitral valve repair, and-in selected cases-targeted PH therapy. In this context, we also highlight gaps in evidence and the need for further research.

Pulmonary hypertension and valvular heart disease

Pulmonary hypertension (PH) is an important contributor to morbidity and mortality in patients with left-sided heart disease, including valvular heart disease. In this context, elevated left atrial pressure primarily leads to the development of post-capillary PH. Despite the fact that repair of left-sided valvular heart disease by surgical or interventional approaches will improve PH, recent studies have highlighted that PH (pre- or post-interventional) remains an important predictor of long-term outcome. Here, we review the current knowledge on PH in valvular heart disease taking into account new hemodynamic PH definitions, and the distinction between post- and pre-capillary components of PH. A specific focus is on the precise characterization of hemodynamics and cardiopulmonary interaction, and on potential strategies for the management of residual PH after mitral or aortic valve interventions. In addition, we highlight the clinical significance of tricuspid regurgitation, which may occur as a primary condition or as a consequence of PH and right heart dilatation (functional). In this context, proper patient selection for potential tricuspid valve interventions is crucial. Finally, the article highlights gaps in evidence, and points toward future perspectives.

Key inflammatory pathways underlying vascular remodeling in pulmonary hypertension

Independent of the underlying cause, pulmonary hypertension (PH) remains a devastating condition that is characterized by limited survival. Cumulating evidence indicates that in addition to a dysbalance of mediators regulating vascular tone and growth factors promoting vascular remodeling, failure to resolve inflammation and altered immune processes play a pivotal role in the development and progression of PH. Here, we highlight the role of key inflammatory pathways in the pathobiology of vascular remodeling and PH, and discuss potential therapeutic interventions that may halt disease progression or even reverse pulmonary vascular remodeling. Perivascular inflammation is present in all forms of PH, and inflammatory pathways involve numerous mediators and cell types including macrophages, neutrophils, T cells, dendritic cells, and mast cells. Dysfunctional bone morphogenic protein receptor 2 (BMPR2) signaling and dysregulated immunity enable the accumulation of macrophages and other inflammatory cells in obliterative vascular lesions. Regulatory T cells (Tregs) were shown to be of particular relevance in the control of inflammatory responses. Key cytokines/chemokines include interleukin-6, functioning via classic or trans-signaling, macrophage migratory inhibitory factor (MIF), but also other mediators such as neutrophil-derived myeloperoxidase. The expanding knowledge on this topic has resulted in multiple opportunities for sophisticated therapeutic interventions.

P4146The six-transmembrane protein Stamp2 protects from hypoxia-induced pulmonary vascular remodeling and pulmonary hypertension via actions in mononuclear cells and CXCL12

Background

The six-transmembrane protein of prostate (Stamp2) is a potent anti-inflammatory player in adipocytes and also in macrophages. Stamp2's actions in these cells protects from diet-induced diabetes and from atherosclerosis mice. As chronic inflammation is a hallmark of pulmonary arterial hypertension (PH), we sought to investigate the role of Stamp2 in PH.

Methods and results

Morphometric analyses of small pulmonary arteries after 3 weeks of chronic hypoxia (10% O2) showed aggravated pulmonary vascular remodeling in Stamp2−/− mice as compared to WT, demonstrated by a significantly reduced number of non-muscularized vessels and higher extent of fully-muscularized vessels. Consequently, right ventricular systolic pressure (RVSP, Millar catheter via right jugular vein) was significantly higher in Stamp2−/− mice (33.4±0.7 mmHg vs. 30.3±1.4, p<0.05). As endothelial (EC) and smooth muscle cells (PASMC) are critical for remodeling processes in PH, the role of Stamp2 in these cells was explored. However, siRNA-mediated knock-down of Stamp2 in human microvascular EC had no effect on apoptotic susceptibility (CellDeath Detection ELISA), or release of IL-6 (qPCR). Furthermore, Stamp2-deficiency in isolated primary PASMC had no effect on proliferation (BrdU incorporation) and chemotaxis (modified Boyden chamber). As Stamp2 deficiency promotes higher expression of inflammatory cytokines (IL6, IL1b, MCP1, TNFa, CXCL12, qPCR) and increased numbers of CD68-positive cells in the lung, actions of Stamp2 in macrophages are potentially driving vascular remodeling in PH. To test this hypothesis, PASMC proliferation and chemotaxis were assessed in response to treatment with supernatants from primary thioglycolate-elicited peritoneal Stamp2−/− or WT-macrophages. These experiments revealed that supernatants from Stamp2−/− macrophages induced PASMC proliferation and chemotaxis significantly stronger, thus providing a link between inflammatory actions in Stamp2 deficiency and vascular remodeling. To gain further insights, a cytokine array was performed with supernatants from Stamp2−/− and WT-macrophages, revealing CXCL12 as the most relevant candidate. Experiments with neutralizing antibodies confirmed the role of CXCL12 in driving Stamp2's actions on vascular remodelling processes in PASMC.

Importantly, Stamp2 expression (qPCR, western blot analyses) was significantly lower in the lung of humans with idiopathic PAH (IPAH), as well as in experimental PH in rats (monocrotalin, sugen/hypoxia) and in mice (hypoxia).

Conclusions

Stamp2 deficiency aggravates hypoxia-induced pulmonary vascular remodeling and pulmonary hypertension in mice. On the cellular level, actions of Stamp2 in macrophages drive vascular remodelling processes in smooth muscle cells via secreted factors such as CXCL12. The finding of decreased expression of Stamp2 in human and various experimental forms of PH points towards a general protective role of Stamp2.

P4511Characteristic hemodynamic and metabolic response patterns differ between patients with stable chronic left vs right heart failure

Background

Patients with chronic left and right heart failure show a reduction in peak oxygen uptake (VO2), even with optimal medical therapy. A non-invasive determination whether the mechanism of exercise limitation is primarily due to left or right-heart failure may be a challenge in clinical practice. The simultaneous analysis of metabolic and hemodynamic responses during exercise may allow an improved differentiation of exercise limitation. However, only little is known about the combined hemodynamic/metabolic exercise response patterns in these patients.

OBJECTIVES

We sought to characterize the simultaneous hemodynamic and metabolic response to exercise in stable patients with chronic, isolated left vs right heart failure.

Methods

We analyzed a cohort of highly selected patients with isolated right heart failure (group 1) and isolated left heart failure (group 2). All patients were in functional class II and III, and under stable medical Treatment. All patients had received right heart catheterization before enrollment. All of the patients in group 1 and none of the patients in group 2 showed an elevated pulmonary vascular resistance (PVR). All patients received a cardiopulmonary exercise test (CPET) with a ramp protocol up to maximal exercise tolerance. During a second visit, a combined CPET/stress echocardiography was performed with a two step constant work rate protocol. For step 1, a workrate below the patients' anaerobic threshold was chosen. For step 2, 80% of the patients' maximum workrate from the ramp test was chosen. Each step was performed until a complete echocardiographic image acquisition was obtained. Echocardiographic parameters, including stroke volume measurements, were obtained once at rest and for each of the two exercise steps.

Results

We recruited 18 patients (n=9 in group 1, n=9 in group 2). There were no significant differences in demographic baseline characteristics. There were no adverse events. In the inital ramp CPET, both groups showed a moderate reduction in peak VO2 (53,0±12,4 vs 63,3±12,8% of predicted). The absolute peak VO2 values, corrected for body weight, showed no significant difference (16,7±4,5 vs 16,5±5,1 ml/min/kg). While the increase in VO2 (Figure 1A) and cardiac index (Figure 1B) during step 1 and step 2 of the simultaneous CPET/stress echocardiography was similar between both groups, the increase of stroke volume index with exercise was significantly reduced in the group with right heart failure, while the group with left heart failure increased stroke volume index during exercise (Figure 1C).

Figure 1

Conclusions

The simultaneous evaluation of hemodynamic and metabolic parameters by CPET/stress echocardiography is safe and may reveal characteristic response patterns to exercise in patients with chronic left vs right heart failure. Patients with right heart failure seem to be less able to increase stroke volume during exercise than patients with left heart failure.

Acknowledgement/Funding

This project was partly funded by Actelion Pharmaceuticals

P4142PI3-kinase delta protects against atherosclerosis progression by governing regulatory T-cell biology

Introduction and purpose

Atherosclerosis is a chronic inflammatory disease of arteries and represents the main underlying cause of death worldwide. Macrophages are major drivers of atherosclerosis by ingestion of lipoproteins, foam cell formation, and secretion of pro-inflammatory mediators. Although macrophages outnumber other leukocytes in atherosclerotic plaques, T and B lymphocytes can shape the course of disease by promoting or mitigating inflammatory responses. Leukocytes highly express the phosphoinositide 3-kinase isoform delta (PI3Kd), exerting a key role in the regulation of immune responses including the activation, proliferation, differentiation, and effector function of lymphocytes. Since macrophages and lymphocytes are all major effectors of atherosclerosis, we aimed to understand the role of PI3Kd in these leukocytes during atherogenesis.

Methods and results

To investigate the role of haematopoietic PI3Kd in atherosclerosis, bone marrow from PI3Kd−/− or PI3Kd+/+ mice was transplanted into LDLR−/− mice. After 6 weeks of feeding on an atherogenic diet, PI3Kd−/− recipient LDLR−/− mice displayed significantly impaired CD4+ and CD8+ T-cell numbers, CD4+ T-cell activation, CD4+ effector T cells, and proatherogenic CD4+ T helper (Th) 1 responses in para-aortic lymph nodes and spleen compared with PI3Kd+/+ transplanted controls. Surprisingly, the net effect of PI3Kd deficiency was a substantial increase of aortic inflammation and atherosclerosis in LDLR−/− mice. Moreover, haematopoietic PI3Kd deficiency augmented macrophage accumulation in atherosclerotic plaques of LDLR−/− mice, whereas major macrophage functions including foam cell formation, efferocytosis, and cytokine secretion were unaffected by PI3Kd inactivation in these phagocytes. However, haematopoietic PI3Kd deficiency led to depletion of atheroprotective B-1 cells and reduction of proatherogenic B-2 cells in LDLR−/− mice. Moreover, haematopoietic PI3Kd deficiency caused a significant reduction of regulatory CD4+ T cells (Tregs) in plaques, para-aortic lymph nodes, and spleen of LDLR−/− mice. Furthermore, PI3Kd−/− Tregs exhibited reduced secretion of anti-inflammatory cytokines IL-10 and TGF-b as well as impaired suppression of CD4+ T-cell proliferation. Consequently, adoptive transfer of PI3Kd+/+ Tregs fully constrains the atherosclerotic burden in PI3Kd−/− transplanted LDLR−/− mice without affecting B cell numbers.

Conclusions

We demonstrate that PI3Kd plays a crucial role in B lymphocytes, Th1 cells, and Tregs during atherogenesis. Lack of PI3Kd signalling in atheroprotective Treg responses outplays its impact on proatherogenic Th1 responses, thus leading to aggravated atherosclerosis. Hence, PI3Kd is a key regulator of Treg biology and thereby protects against atherosclerosis progression.

Acknowledgement/Funding

Center for Molecular Medicine Cologne (CMMC) and the Marga and Walter Boll-Stiftung

P1937Deficiency of PI 3-kinase isoform p110alpha in smooth muscle cells impairs vascular integrity and promotes aortic aneurysm formation

Background

The pathobiology of aortic aneurysms is characterized by vascular inflammation, extracellular matrix degeneration, and particularly by loss and dedifferentiation of vascular smooth muscle cells (SMCs). In SMCs, the PI 3-kinase isoform p110α mediates receptor tyrosine kinase dependent proliferation, chemotaxis, and survival. Smooth muscle specific p110α deficient mice (SM-p110α−/− mice) display reduced medial wall thickness, substantially reduced neointima formation and media hypertrophy after balloon injury of the carotid artery.

Objective

We hypothesized that loss of p110α signaling impairs vascular integrity and promotes development and progression of abdominal aortic aneurysms (AAA). We aimed to elucidate the impact of p110α deficiency on vascular integrity, SMC phenotypic modulation, vascular inflammation, and AAA formation.

Methods and results

Ultra-structural characterization of aortic wall morphology in abdominal aortas from SM-p110α−/− mice by transmission electron microscopy (TEM) revealed disarranged structure of tunica media as indicated by disorganized elastic fibers, detached SMCs, and elastic fiber breaks. Western blots showed reduced elastin and fibrillin expression in SMCs from p110α−/− mice. Media thickness was significantly reduced in abdominal aortas from SM-p110α−/− mice compared to wild type (WT) controls (29.0±3.1 vs. 42.5±4.1 μm). Lack of p110α decreased expression of differentiation markers SM-α-actin and SM-MHC. p110α deficiency significantly diminished responsiveness of aortic rings to vasodilator acetylcholine. These data indicate loss of differentiation and impaired contractility of p110α−/− SMCs. We subjected SM-p110α−/− mice and WT littermate controls to the porcine pancreatic elastase (PPE) model of AAA. PPE was infused into the infrarenal aorta, respectively, to induce AAA formation. Ultrasonic examination of abdominal aortas demonstrated an enlarged aortic diameter in PPE challenged mice. AAA formation was significantly (p<0.01) enhanced in SM-p110α−/− (0.46±0.12 mm, n=8) compared to SM-p110α+/+ mice (0.18±0.03 mm, n=4). These data indicate a protective function of p110α in AAA formation. Immunocytochemistry of the aortic medial compartment from PPE-perfused SM-p110α−/− mice revealed significantly increased MOMA-2+ monocyte/macrophage content indicating augmented aortic inflammation during AAA formation compared to WT controls. Furthermore, SMCs from SM-p110α−/− mice expressed reduced amounts of anti-inflammatory angiopoietin1 compared to p110α+/+ SMCs. Moreover, frequent apoptotic/necrotic SMCs were found in the aortic media of SM-p110α−/− mice by TEM, potentially contributing to vascular inflammation in a critical fashion.

Conclusion

These data indicate that p110α signaling critically contributes to vascular integrity via maintaining SMC plasticity, elastic fiber homeostasis, and anti-inflammatory processes. Consequently, lack of proper p110α signaling promotes progression of AAA formation.

4973Efficacy and safety of selexipag in pulmonary arterial hypertension (PAH) patients with and without significant cardiovascular (CV) comorbidities

Introduction

Many PAH patients today have a number of CV comorbidities, yet data on the efficacy and safety of therapies in such patients remain scarce. Most recent PAH clinical trials also include patients with comorbidities.

Purpose

To assess the long-term efficacy and safety of the oral, selective IP prostacyclin receptor agonist, selexipag, in PAH patients with and without significant CV comorbidities using post hoc analysis of GRIPHON data.

Methods

GRIPHON enrolled 1156 PAH patients randomised 1:1 to placebo:selexipag. The present analysis includes patients with right heart catheterisation within 1 year of randomisation who were categorised as with or without CV comorbidities. Patients with CV comorbidities were defined as having ≥3 of the following: body mass index (BMI) >30 kg/m2, history of essential hypertension, diabetes mellitus, or historical evidence of significant coronary artery disease; if PAWP/LVEDP was >12 but <15 mmHg, pulmonary vascular resistance (PVR) had to be >500 dyn.sec/cm5; if PAWP/LVEDP was <12, then PVR had to be >300 dyn.sec/cm5. Selexipag effect on time to first morbidity/mortality (M/M) event up to end of treatment was assessed for both subgroups. Baseline (BL) adjusted treatment hazard ratios with 95% CIs were calculated using Cox models. Model building involved stepwise backward elimination of BL covariates.

Results

752 PAH patients could be categorised based on these criteria (99 with CV comorbidities, 653 without). At BL, patients with CV comorbidities were older (median [range] 60 [28–80] vs 46 [18–78] yrs), had higher BMI (mean [SD] 33.3 [7.23] vs 26.0 [5.64] kg/m2) and lower 6-minute walk distance (mean [SD] 319 [95.7] vs 354 [79.3] m) vs those without. A greater proportion were from Western Europe/Australia/North America (60.6% vs 38.9%) and in WHO functional class III (69.7% vs 49.9%). At BL, 82.8% of patients with CV comorbidities were receiving PAH therapies vs 75.7% of those without. As expected, at BL a higher proportion of patients with CV comorbidities (vs without) had previous/concomitant cardiac disease (62.6% vs 43.0%), metabolism/nutrition disorders (75.8% vs 31.2%), respiratory/thoracic/mediastinal disorders (59.6% vs 37.5%) and vascular disorders (76.8% vs 37.4%). Selexipag reduced the risk of M/M events vs placebo in both subgroups (Figure), with no evidence of an inconsistent treatment effect (interaction p-value=0.1544). Adverse events leading to treatment discontinuation were reported in 35.4% (25.9% selexipag, 46.7% placebo) of patients with CV comorbidities and 35.0% (32.0% selexipag, 38.0% placebo) of those without. Common prostacyclin associated side effects observed with selexipag (headache, diarrhoea, nausea) were reported at a similar incidence in both subgroups.

Conclusions

Selexipag had a beneficial effect on long-term outcome in PAH patients both with and without CV comorbidities. Safety in both groups was consistent with the known profile of selexipag.

Acknowledgement/Funding

Actelion Pharmaceuticals Ltd

[Telemonitoring and pulmonary artery pressure-guided treatment of heart failure]

Heart failure (HF) is an emerging epidemic associated with significant morbidity and mortality, impaired quality of life and high healthcare costs. Despite major advances in pharmacological and device-based therapies, mortality and morbidity have remained high after an index hospitalization for acute cardiac decompensation (ACD). Randomized trials evaluating various forms of noninvasive telemonitoring failed to improve rehospitalization rates in such patients, possibly due to lack of sensitivity of clinical signs and symptoms as early indicators of HF. Among different implantable monitoring devices, wireless remote monitoring of the pulmonary artery pressure (PAP) with the CardioMEMS™ sensor (Abbott, Sylmar, CA, USA) has been shown to be safe and clinically effective in the USA. The patients showed substantial reductions in hospital admissions for ACD, irrespective of left ventricular pump function, because PAP-guided HF management facilitates timely recognition of incipient ACD and appropriate modification of medical treatment before hospitalization becomes unavoidable. These encouraging results have also stimulated evaluation of this novel technology outside the USA. Studies are also underway in Europe and European HF guidelines recommend considering implantation of a CardioMEMS™ sensor in high-risk patients (class IIb-B). More technologically refined implantable hemodynamic monitoring systems allowing, for example, left atrial pressure measurements, are under development. Promising novel approaches to using information from such devices include continuous hemodynamic monitoring and patient self-management based on the pressure information. Thus, pressure-guided HF management is likely to further expand in the future and may help improve clinical outcomes also in high-risk HF populations.

Spin Stripe Order in a Square Planar Trilayer Nickelate

Trilayer nickelates, which exhibit a high degree of orbital polarization combined with an electron count (d^{8.67}) corresponding to overdoped cuprates, have been identified as a promising candidate platform for achieving high-T_{c} superconductivity. One such material, La_{4}Ni_{3}O_{8}, undergoes a semiconductor-insulator transition at ∼105  K, which was recently shown to arise from the formation of charge stripes. However, an outstanding issue has been the origin of an anomaly in the magnetic susceptibility at the transition and whether it signifies the formation of spin stripes akin to single layer nickelates. Here we report single crystal neutron diffraction measurements (both polarized and unpolarized) that establish that the ground state is indeed magnetic. The ordering is modeled as antiferromagnetic spin stripes that are commensurate with the charge stripes, the magnetic ordering occurring in individual trilayers that are essentially uncorrelated along the crystallographic c axis. A comparison of the charge and spin stripe order parameters reveals that, in contrast to single-layer nickelates such as La_{2-x}Sr_{x}NiO_{4} as well as related quasi-2D oxides including manganites, cobaltates, and cuprates, these orders uniquely appear simultaneously, thus demonstrating a stronger coupling between spin and charge than in these related low-dimensional correlated oxides.

Glycemic Control Outcomes Following Three Weeks of Added Sugar-Sweetened Beverages or 100% Fruit Juice: A Randomized Controlled Trial (P12-015-19)

Objectives

Regular consumption of sugar-sweetened beverages (SSBs) is associated with increased risk for type 2 diabetes mellitus and other obesity-related diseases. Evidence regarding the effect of 100% fruit juice on glycemic control is conflicting, with little research assessing the metabolic effects of SSBs versus 100% fruit juice, particularly in young, healthy individuals. Therefore, the aim of the current study was to determine whether there were differences in glycemic control outcomes following three weeks of added caffeine-free soda, 100% fruit juice, or water in healthy, young adults.

Methods

In a 3-arm randomized controlled trial, 36 participants (21.2 ± 2.8 yrs) consumed one of three beverages for three weeks: water (W), caffeine-free soda (S), or 100% fruit juice (FJ). At baseline and following the 3-week intervention, participants completed anthropometric (height, weight, waist circumference, body composition via dual energy x-ray absorptiometry) and glycemic control assessments (fasting glucose (mg/dL), fasting insulin (IU/mL), and a 2-hour glucose tolerance test (OGTT)). Following baseline assessments, participants consumed two servings/day (∼710 mL) of their randomized beverage for three weeks, along with their habitual diets. Insulin resistance was calculated using homeostatic model assessment (HOMA-IR). Differences between beverages for glycemic control outcomes were determined using ANOVA.

Results

Following the 3-week intervention, changes in fasting glucose were not significantly different between beverage conditions (W:4.70 ± 7.57%, S:5.46 ± 9.79%, FJ:4.93 ± 5.32%; P = 0.97), nor were changes in fasting insulin (W:25.77 ± 33.65%, S:15.71% ± 69.84%, FJ:25.86 ± 54.92%; P = 0.88). Changes in HOMA-IR were not different between beverage conditions (P = 0.96) and similarly, 2-hour OGTT revealed no differences between beverage conditions for glucose (P = 0.82) or insulin incremental area under the curve (P = 0.44).

Conclusions

In healthy, young adults, under free-living conditions, there were no differences in glycemic control outcomes when adding two servings of SSBs as compared to 100% fruit juice for three weeks. Longer-term trials are needed to elucidate the potential differential glycemic control responses to SSBs versus 100% fruit juice.

Funding Sources

N/A.

Glycemic Response to Two Doses of Resistant Starch Type 4: A Randomized Controlled Crossover Trial (P08-091-19)

Objectives

Resistant starches (RS) have a beneficial effect on glucose and insulin responses in the postprandial period following carbohydrate (CHO) consumption. In comparison to resistant starch types 1–3, there is little evidence investigating the effects of resistant starch type 4 (RS4) on these metabolic responses. The primary aim of the current study was to determine whether the glycemic response to a nutritional RS4 bar (RS4) was different compared to a puffed wheat bar (PWB), provided at the standard testing amount of 50 g available CHO and a lower dose of 30 g available CHO, thereby investigating a dose-response effect.

Methods

Apparently healthy adults (n = 15; 26.1 ± 4.8yrs) participated in this controlled randomized crossover trial. All participants completed six trials: 50 g dextrose control drink (50DEX), 30 g dextrose control drink (30DEX); and nutrition bars containing: 50 g available CHO of PWB or RS4 (50PWB; 50RS4), and 30 g available CHO PWB or RS4 (30PWB; 30RS4). Participants fasted for 10–12 hrs prior to each visit with a minimum 72hr washout period between trials. Blood glucose was measured via LDX Cholestech at baseline and 10, 20, 30, 60, 90, and 120 min post consumption. Primary outcomes were determined using mixed-effects models in GraphPad Prism 8.0.1.

Results

Glucose incremental area under the curve (iAUC) was not significantly different between the 50 g conditions (P = 0.054). However, peak blood glucose was significantly lower in the 50RS4 condition compared to 50PWB and 50CON (P = 0.027; P = 0.004 respectively); and there was no difference between 50PWB and 50CON (P = 0.496). While 30RS4 and 30PWB glucose iAUCs were lower compared to 30CON (P = 0.002), there was no difference between 30RS4 and 30PWB (P = 0.48). Peak blood glucose was reduced for both 30PWB and 30RS4 when compared to 30CON (P = 0.005; P = 0.002 respectively), with no difference between 30 g CHO bars (P = 0.22).

Conclusions

These results indicate a potential dose-response effect for RS4 on postprandial glycemia. Specifically, at the 50 g available CHO standard testing amount, RS4 reduced peak blood glucose as compared to the 50PWB control. At the lower dose of available CHO, there was not a statistically significant beneficial effect for 30RS4 on postprandial glycemia. There may be a potential floor effect where RS4 has no further benefit when available CHO is low.

Funding Sources

MGP Ingredients Inc.

Variability in Dietary Quality of School Lunches Meeting National School Lunch Program Standards by Socioeconomic Status and Rurality (P04-191-19)

Objectives

Recent research suggests the possibility for significant variability in nutrient content and dietary quality (DQ) of school lunches, even when meeting National School Lunch Program (NSLP) nutrition standards. The purpose of this study was to determine whether there were differences in nutrient content and DQ by socioeconomic status (SES) and rurality, among middle school lunch menus meeting NSLP standards.

Methods

All 283 Kansas school districts were stratified into high and low SES groups (< 50% or > 50% of students received free/reduced-price lunch). Forty-five menus from low and from high SES strata (N = 90) were obtained from websites of randomly selected school districts for the same time period (first six weeks of school). Included menus were also stratified for analyses by rurality, determined by National Center for Education Statistics locales. Thirty days of each menu were portioned per NSLP standards for the middle school age group and per standardized assumptions across all menus. Portioned menus were analyzed for macro- and micro-nutrient content using ESHA Food Processor. Daily DQ scores were calculated using the Healthy Eating Index (HEI) 2015. Two-way ANOVA was used to determine differences in nutrient content and DQ by SES and rurality, with Bonferroni correction for multiple comparisons. Effect size was calculated using Cohen's d.

Results

Eighty-five menus were included in final analyses. There were significant differences between high SES vs. low SES menus for added sugar (‒0.4 g or ‒80%, Cohen's d = 0.78, P < 0.001) and calcium (5.3 mg or 1%, d = ‒0.22, P = 0.001) favoring high SES menus, and sodium (54.1 mg or 48%, d = ‒0.66, P = 0.001) favoring low SES menus. There were no significant differences in nutrient content between city, suburban, town, or rural locales (ps > 0.05). HEI scores did not differ by SES or rurality (ps > 0.05), with mean score and standard deviation of 62.0 ± 4.0 across all schools.

Conclusions

There were few differences in nutrient content and DQ with minimal clinical significance when comparing middle school lunch menus in Kansas by SES and rurality. Efforts to improve school lunch DQ should focus on all school foodservice operations, not specifically low SES or rural, although these schools may have other foodservice needs outside the scope of this study.

Funding Sources

None.

The relation of local order to material properties in relaxor ferroelectrics

Correlating electromechanical and dielectric properties with nanometre-scale order is the defining challenge for the development of piezoelectric oxides. Current lead (Pb)-based relaxor ferroelectrics can serve as model systems with which to unravel these correlations, but the nature of the local order and its relation to material properties remains controversial. Here we employ recent advances in diffuse scattering instrumentation to investigate crystals that span the phase diagram of PbMg_1/3Nb_2/3O₃-xPbTiO₃ (PMN-xPT) and identify four forms of local order. From the compositional dependence, we resolve the coupling of each form to the dielectric and electromechanical properties observed. We show that relaxor behaviour does not correlate simply with ferroic diffuse scattering; instead, it results from a competition between local antiferroelectric correlations, seeded by chemical short-range order, and local ferroic order. The ferroic diffuse scattering is strongest where piezoelectricity is maximal and displays previously unrecognized modulations caused by anion displacements. Our observations provide new guidelines for evaluating displacive models and hence the piezoelectric properties of environmentally friendly next-generation materials.