A snapshot on HIV-1 evolution through the identification of phylogenetic-specific properties of HIV-1 integrases M/O.

Transmissions of simian viruses to humans has originated the different groups of HIV-1. We recently identified a functional motif (CLA), in the C-terminal domain of the integrase, essential for integration in HIV-1 group M. Here, we found that the motif is instead dispensable in group O isolates, because of the presence, in the N-terminal domain of HIV-1 O of a specific sequence, Q7G27P41H44, that we define as the NOG motif. Alterations of reverse transcription and of 3' processing observed by mutating the CLA motif of IN M are fully rescued to wt levels by inserting the sequence of the NOG motif in the N-ter of the protein. These results indicate that the two motifs (CLA and NOG) functionally complement each other and a working model accounting for these observations is proposed. The establishment of these two alternative motifs seems to be due to the different phylogenetic origin and history of these two groups. Indeed, the NOG motif is already present in the ancestor of group O (SIVgor) while it is absent from SIVcpzPtt, the ancestor of group M. The CLA motif, instead, seems to have emerged after SIVcpzPtt has been transferred to humans, since no conservation is found at the same positions in these simian viruses. These results show the existence of two-group specific motifs in HIV-1 M and O integrases. In each group, only one of the motifs is functional, potentially leading the other motif to diverge from its original function and, in an evolutionary perspective, assist other functions of the protein, further increasing HIV genetic diversity.

Toll-Like Receptor 3 Mediates Aortic Stenosis Through a Conserved Mechanism of Calcification.

BACKGROUND: Calcific aortic valve disease (CAVD) is characterized by a phenotypic switch of valvular interstitial cells to bone-forming cells. Toll-like receptors (TLRs) are evolutionarily conserved pattern recognition receptors at the interface between innate immunity and tissue repair. Type I interferons (IFNs) are not only crucial for an adequate antiviral response but also implicated in bone formation. We hypothesized that the accumulation of endogenous TLR3 ligands in the valvular leaflets may promote the generation of osteoblast-like cells through enhanced type I IFN signaling. METHODS: Human valvular interstitial cells isolated from aortic valves were challenged with mechanical strain or synthetic TLR3 agonists and analyzed for bone formation, gene expression profiles, and IFN signaling pathways. Different inhibitors were used to delineate the engaged signaling pathways. Moreover, we screened a variety of potential lipids and proteoglycans known to accumulate in CAVD lesions as potential TLR3 ligands. Ligand-receptor interactions were characterized by in silico modeling and verified through immunoprecipitation experiments. Biglycan (Bgn), Tlr3, and IFN-α/ß receptor alpha chain (Ifnar1)-deficient mice and a specific zebrafish model were used to study the implication of the biglycan (BGN)-TLR3-IFN axis in both CAVD and bone formation in vivo. Two large-scale cohorts (GERA [Genetic Epidemiology Research on Adult Health and Aging], n=55 192 with 3469 aortic stenosis cases; UK Biobank, n=257 231 with 2213 aortic stenosis cases) were examined for genetic variation at genes implicated in BGN-TLR3-IFN signaling associating with CAVD in humans. RESULTS: Here, we identify TLR3 as a central molecular regulator of calcification in valvular interstitial cells and unravel BGN as a new endogenous agonist of TLR3. Posttranslational BGN maturation by xylosyltransferase 1 (XYLT1) is required for TLR3 activation. Moreover, BGN induces the transdifferentiation of valvular interstitial cells into bone-forming osteoblasts through the TLR3-dependent induction of type I IFNs. It is intriguing that Bgn-/-, Tlr3-/-, and Ifnar1-/- mice are protected against CAVD and display impaired bone formation. Meta-analysis of 2 large-scale cohorts with >300 000 individuals reveals that genetic variation at loci relevant to the XYLT1-BGN-TLR3-interferon-α/ß receptor alpha chain (IFNAR) 1 pathway is associated with CAVD in humans. CONCLUSIONS: This study identifies the BGN-TLR3-IFNAR1 axis as an evolutionarily conserved pathway governing calcification of the aortic valve and reveals a potential therapeutic target to prevent CAVD.

Hepatocyte growth factor as indicator for subclinical atherosclerosis.

Background: Hepatocyte growth factor (HGF) is a pleiotropic cytokine mainly produced by mesenchymal cells. After endothelial damage by oxidized low-density lipoprotein (LDL), HGF is produced and released into the circulation in response. Due to this mechanism HGF has been proposed as possible clinical biomarker for clinical as well as subclinical atherosclerosis. Patients and methods: The conducted study is an observational, single centre, cohort study, including 171 patients with at least one cardiovascular risk factor or already established cardiovascular disease (CVD). Each patient underwent 3D plaque volumetry of the carotid and femoral arteries as well as physical examination and record of the medical history. Additionally, plasma HGF and further laboratory parameters like high sensitivity C-reactive protein and LDL-cholesterol were determined. Results: 169 patients were available for statistical analysis. In bivariate correlation, HGF showed a highly significant correlation with total plaque volume (TPV, r=0.48; p<0.001). In receiver operating characteristic (ROC) analysis for high TPV, HGF showed an area under the curve (AUC) of 0.68 (CI 95%: 0.59-0.77, p<0.001) with a sensitivity of 78% and a specificity of 52% to predict high TPV at a cut-off of 959 ng/ml. In the ROC-analysis for the presence of CVD, HGF demonstrated an AUC of 0.65 (95% CI 0.55-0.73; p=0.01) with a sensitivity of 77% and a specificity of 52%. Conclusions: Higher plasma levels of HGF are associated with higher atherosclerotic plaque volume as measured by 3D-ultrasound.

The HIV-1 Integrase C-Terminal Domain Induces TAR RNA Structural Changes Promoting Tat Binding.

Recent evidence indicates that the HIV-1 Integrase (IN) binds the viral genomic RNA (gRNA), playing a critical role in the morphogenesis of the viral particle and in the stability of the gRNA once in the host cell. By combining biophysical, molecular biology, and biochemical approaches, we found that the 18-residues flexible C-terminal tail of IN acts as a sensor of the peculiar apical structure of the trans-activation response element RNA (TAR), interacting with its hexaloop. We show that the binding of the whole IN C-terminal domain modifies TAR structure, exposing critical nucleotides. These modifications favour the subsequent binding of the HIV transcriptional trans-activator Tat to TAR, finally displacing IN from TAR. Based on these results, we propose that IN assists the binding of Tat to TAR RNA. This working model provides a mechanistic sketch accounting for the emerging role of IN in the early stages of proviral transcription and could help in the design of anti-HIV-1 therapeutics against this new target of the viral infectious cycle.

Cardiopulmonary recovery after COVID-19: an observational prospective multicentre trial.

BACKGROUND: After the 2002/2003 severe acute respiratory syndrome outbreak, 30% of survivors exhibited persisting structural pulmonary abnormalities. The long-term pulmonary sequelae of coronavirus disease 2019 (COVID-19) are yet unknown, and comprehensive clinical follow-up data are lacking. METHODS: In this prospective, multicentre, observational study, we systematically evaluated the cardiopulmonary damage in subjects recovering from COVID-19 at 60 and 100 days after confirmed diagnosis. We conducted a detailed questionnaire, clinical examination, laboratory testing, lung function analysis, echocardiography and thoracic low-dose computed tomography (CT). RESULTS: Data from 145 COVID-19 patients were evaluated, and 41% of all subjects exhibited persistent symptoms 100 days after COVID-19 onset, with dyspnoea being most frequent (36%). Accordingly, patients still displayed an impaired lung function, with a reduced diffusing capacity in 21% of the cohort being the most prominent finding. Cardiac impairment, including a reduced left ventricular function or signs of pulmonary hypertension, was only present in a minority of subjects. CT scans unveiled persisting lung pathologies in 63% of patients, mainly consisting of bilateral ground-glass opacities and/or reticulation in the lower lung lobes, without radiological signs of pulmonary fibrosis. Sequential follow-up evaluations at 60 and 100 days after COVID-19 onset demonstrated a vast improvement of symptoms and CT abnormalities over time. CONCLUSION: A relevant percentage of post-COVID-19 patients presented with persisting symptoms and lung function impairment along with radiological pulmonary abnormalities >100 days after the diagnosis of COVID-19. However, our results indicate a significant improvement in symptoms and cardiopulmonary status over time.

NKNK: a New Essential Motif in the C-Terminal Domain of HIV-1 Group M Integrases.

Using coevolution network interference based on comparison of two phylogenetically distantly related isolates, one from the main group M and the other from the minor group O of HIV-1, we identify, in the C-terminal domain (CTD) of integrase, a new functional motif constituted by four noncontiguous amino acids (N222K240N254K273). Mutating the lysines abolishes integration through decreased 3' processing and inefficient nuclear import of reverse-transcribed genomes. Solution of the crystal structures of wild-type (wt) and mutated CTDs shows that the motif generates a positive surface potential that is important for integration. The number of charges in the motif appears more crucial than their position within the motif. Indeed, the positions of the K's could be permutated or additional K's could be inserted in the motif, generally without affecting integration per se Despite this potential genetic flexibility, the NKNK arrangement is strictly conserved in natural sequences, indicative of an effective purifying selection exerted at steps other than integration. Accordingly, reverse transcription was reduced even in the mutants that retained wt integration levels, indicating that specifically the wt sequence is optimal for carrying out the multiple functions that integrase exerts. We propose that the existence of several amino acid arrangements within the motif, with comparable efficiencies of integration per se, might have constituted an asset for the acquisition of additional functions during viral evolution.IMPORTANCE Intensive studies of HIV-1 have revealed its extraordinary ability to adapt to environmental and immunological challenges, an ability that is also at the basis of antiviral treatment escape. Here, by deconvoluting the different roles of the viral integrase in the various steps of the infectious cycle, we report how the existence of alternative equally efficient structural arrangements for carrying out one function opens up the possibility of adapting to the optimization of further functionalities exerted by the same protein. Such a property provides an asset to increase the efficiency of the infectious process. On the other hand, though, the identification of this new motif provides a potential target for interfering simultaneously with multiple functions of the protein.

The haemochromatosis gene Hfe and Kupffer cells control LDL cholesterol homeostasis and impact on atherosclerosis development.

AIMS: Imbalances of iron metabolism have been linked to the development of atherosclerosis. However, subjects with hereditary haemochromatosis have a lower prevalence of cardiovascular disease. The aim of our study was to understand the underlying mechanisms by combining data from genome-wide association study analyses in humans, CRISPR/Cas9 genome editing, and loss-of-function studies in mice. METHODS AND RESULTS: Our analysis of the Global Lipids Genetics Consortium (GLGC) dataset revealed that single nucleotide polymorphisms (SNPs) in the haemochromatosis gene HFE associate with reduced low-density lipoprotein cholesterol (LDL-C) in human plasma. The LDL-C lowering effect could be phenocopied in dyslipidaemic ApoE-/- mice lacking Hfe, which translated into reduced atherosclerosis burden. Mechanistically, we identified HFE as a negative regulator of LDL receptor expression in hepatocytes. Moreover, we uncovered liver-resident Kupffer cells (KCs) as central players in cholesterol homeostasis as they were found to acquire and transfer LDL-derived cholesterol to hepatocytes in an Abca1-dependent fashion, which is controlled by iron availability. CONCLUSION: Our results disentangle novel regulatory interactions between iron metabolism, KC biology and cholesterol homeostasis which are promising targets for treating dyslipidaemia but also provide a mechanistic explanation for reduced cardiovascular morbidity in subjects with haemochromatosis.

Gene therapy with the angiogenic neuropeptide secretoneurin ameliorates experimental diabetic neuropathy.

The pathogenesis of diabetic neuropathy remains enigmatic. Damage to the vasa nervorum may be responsible for this disorder. Recently, we showed that secretoneurin (SN) induces angiogenesis in hindlimb and myocardial ischemia. Moreover, beneficial effects were observed in wound healing. We therefore hypothesized that SN therapy may ameliorate diabetic neuropathy. We used db/db mice as animal model for neuropathy. Gene therapy was accomplished by intramuscular injection of SN plasmid along the sciatic nerve. Sciatic nerve motor and sensory conduction velocities were then measured for 9 wk. Nerve conduction velocities showed normal values in heterozygous mice for the observational period, but were severely reduced in homozygous mice in which velocities were significantly improved by SN, but not by control plasmid gene therapy. The reaction time in the tail-flick test improved significantly in SN-treated animals. The induction of growth of vasa nervorum seems to be part of the underlying mechanism. In addition, SN positively affected Schwann cell function in vitro and induced activation of important signaling pathways. Our observations suggest that SN exerts beneficial effects on nerve function in vivo and on Schwann cells in vitro. It therefore may be a promising treatment option for diabetic neuropathy.-Theurl, M., Lener, D., Albrecht-Schgoer, K., Beer, A., Schgoer, W., Liu, Y., Stanzl, U., Fischer-Colbrie, R., Kirchmair, R. Gene therapy with the angiogenic neuropeptide secretoneurin ameliorates experimental diabetic neuropathy.

Topical secretoneurin gene therapy accelerates diabetic wound healing by interaction between heparan-sulfate proteoglycans and basic FGF.

Diabetic foot ulcers represent a therapeutic problem of high clinical relevance. Reduced vascular supply, neuropathy and diminished expression of growth factors strongly contribute to wound healing impairment in diabetes. Secretoneurin, an angiogenic neuropeptide, has been shown to improve tissue perfusion in different animal models by increasing the amount of vessels in affected areas. Therefore, topical secretoneurin gene therapy was tested in a full thickness wound healing model in diabetic db/db mice. Secretoneurin significantly accelerated wound closure in these mice and immunohistochemistry revealed higher capillary and arteriole density in the wounded area compared to control mice. In-vitro, the mechanism of action of secretoneurin on human dermal microvascular endothelial cells was evaluated in normal and diabetic cells. Secretoneurin shows positive effects on in vitro angiogenesis, proliferation and apoptosis of these cells in a basic fibroblast growth factor dependent manner. A small molecular weight inhibitor revealed fibroblast growth factor receptor 3 as the main receptor for secretoneurin mediated effects. Additionally, we could identify heparan-sulfates as important co-factor of secretoneurin induced binding of basic fibroblast growth factor to human dermal endothelial cells. We suggest topical secretoneurin plasmid therapy as new tool for delayed wound healing in patients suffering from diabetes.

Correlation of 99mTc-DPD bone scintigraphy with histological amyloid load in patients with ATTR cardiac amyloidosis.

BACKGROUND: The significance of measuring 99mTc-labelled-3,3-diphosphono-1,2-propanodicarboxylic acid (99mTc-DPD) in transthyretin (ATTR) cardiac amyloidosis has not been adequately studied. This single-centre observational study evaluated the correlation between 99mTc-DPD scintigraphy and histological amyloid load in endomyocardial biopsy (EMB). METHODS: Twenty-eight patients with biopsy-proven ATTR amyloidosis and concomitantly available 99mTc-DPD scintigraphy were included. Visual Perugini scoring, and (semi-)quantitative analysis of cardiac 99mTc-DPD uptake by planar whole-body imaging and single photon emission computed tomography (SPECT/CT) using regions of interest (ROI) were performed. From this, heart-to-whole-body ratio (H/WB) and heart-to-contralateral-chest ratio (H/CL) were calculated. The histological amyloid load was quantified using two different staining methods. RESULTS: Increased cardiac tracer uptake was documented in all patients (planar: ROImean 129 ± 37 cps; SPECT/CT: ROImean 369 ± 142 cps). Histological amyloid load (19 ± 13%) significantly correlated with Perugini score (r = 0.69, p < .001) as well as with cardiac 99mTc-DPD uptake (planar: r = 0.64, p < .001; H/WB: r = 0.50, p = .014; SPECT/CT: r = 0.53, p = .008; H/CL: r = 0.43, p = .037) (results are shown for correlations with Congo Red-staining). CONCLUSION: In ATTR, cardiac 99mTc-DPD uptake significantly correlated with histological amyloid load in EMB. Further studies are needed to implement thresholds in cardiac 99mTc-DPD uptake measurements for risk stratification and guidance of therapy.

Increasing Soluble P-Selectin Levels Predict Higher Peripheral Atherosclerotic Plaque Progression.

BACKGROUND AND AIMS: The adhesion molecule P-selectin is expressed by endothelial cells and platelets. It is involved in platelet activation and leukocyte adhesion, both important processes in the pathogenesis of atherosclerosis. Our study was designed to assess the predictive value of soluble P-selectin (sP-selectin) on the progression of peripheral atherosclerosis. METHODS: This is an observational, single-center, cohort study that included 443 patients with established cardiovascular disease (CVD) or at least one cardiovascular risk factor. Over a period of 4 years, each patient underwent three-dimensional (3D) ultrasound to assess the plaque volume of the carotid and femoral arteries once per year. In addition, plasma sP-selectin levels were measured at each visit. The association between changes in sP-selectin and peripheral atherosclerotic plaque progression was assessed using growth curve models. RESULTS: 338 patients were available for statistical analysis. Each standard deviation increase in sP-selectin was significantly (p < 0.001) associated with a 46.09 mm3 higher plaque volume. In ROC-analysis, changes in sP-selectin over time showed an optimal cut-off value around Δ 0.0 µg/mL sP-selectin and significantly improved the predictive value of the ESC-SCORE (AUC for the combination of both parameters was 0.75 (95% CI 0.68-0.81, p < 0.001). Patients with increasing sP-selectin showed a significantly higher plaque progression compared to patients with decreasing or stable sP-selectin levels (202 mm3 vs. 110 mm3, p < 0.001). CONCLUSIONS: Increasing sP-selectin levels can predict higher atherosclerotic plaque progression as measured by 3D ultrasound. We suggest serial measurements of sP-selectin as an easily measurable biomarker for peripheral atherosclerotic plaque progression.

Inverse Correlation of Cholesterol Efflux Capacity with Peripheral Plaque Volume Measured by 3D Ultrasound.

INTRODUCTION: Cardiovascular disease (CVD) is a systemic multifocal illness called atherosclerosis that causes artery constriction and blockage. By causing cholesterol to build up in the artery wall, hypercholesterolemia is a major factor in the pathophysiology of atherosclerotic plaque development. Reverse cholesterol transport is the process of transporting cholesterol from the periphery back to the liver through cholesterol efflux mediated by high-density lipoprotein (HDL). It was suggested that the cholesterol efflux capacity (CEC), which is inversely linked with cardiovascular risk, can serve as a stand-in measure for reverse cholesterol transport. In this work, we sought to investigate a potential link between the peripheral plaque volume (PV) and CEC. METHODS: Since lipid-lowering therapy interferes with CEC, we performed a cross-sectional study of 176 patients (48.9% females) with one cardiovascular risk factor or known CVD that did not currently take lipid-lowering medication. CEC was determined using cAMP-treated 3H-cholesterol-labeled J774 cells. Cholesterol ester transfer protein (CETP)-mediated cholesterol ester transfer was measured by quantifying the transfer of cholesterol ester from radiolabeled exogenous HDL cholesterol to Apolipoprotein B-containing lipoproteins. PV in the carotid and the femoral artery, defined as the total PV, was measured using a 3D ultrasound system equipped with semi-automatic software. RESULTS: In our patients, we discovered an inverse relationship between high total PV and CEC (p = 0.027). However, there was no connection between total PV and low-density lipoprotein cholesterol, lipoprotein (a), or CETP-mediated cholesterol ester transfer. CONCLUSION: In patients not receiving lipid-lowering treatment, CEC inversely correlates with peripheral atherosclerosis, supporting its role in the pathophysiology of atherosclerosis.

The angiogenic neuropeptide catestatin exerts beneficial effects on human coronary vascular cells and cardiomyocytes.

INTRODUCTION: Myocardial infarction (MI) induces irreversible tissue damage, eventually leading to heart failure. Exogenous induction of angiogenesis positively influences ventricular remodeling after MI. Recently, we could show that therapeutic angiogenesis by the neuropeptide catestatin (CST) restores perfusion in the mouse hind limb ischemia model by the induction of angio-, arterio- and vasculogenesis. Thus, we assumed that CST might exert beneficial effects on cardiac cells. METHODS/RESULTS: To test the effect of CST on cardiac angiogenesis in-vitro matrigel assays with human coronary artery endothelial cells (HCAEC) were performed. CST significantly mediated capillary like tube formation comparable to vascular endothelial growth factor (VEGF), which was used as positive control. Interestingly, blockade of bFGF resulted in abrogation of observed effects. Moreover, CST induced proliferation of HCAEC and human coronary artery smooth muscle cells (HCASMC) as determined by BrdU-incorporation. Similar to the matrigel assay blockade of bFGF attenuated the effect. Consistent with these findings western blot assays revealed a bFGF-dependent phosphorylation of extracellular-signal regulated kinase (ERK) 1/2 by CST in these cell lines. Finally, CST protected human cardiomyocytes in-vitro from apoptosis. CONCLUSION: CST might qualify as potential candidate for therapeutic angiogenesis in MI.

SARS-CoV-2 activates the TLR4/MyD88 pathway in human macrophages: A possible correlation with strong pro-inflammatory responses in severe COVID-19.

Background: Toll-like receptors (TLRs) play a pivotal role in the immunologic response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Exaggerated inflammatory response of innate immune cells, however, may drive morbidity and death in Coronavirus disease 19 (COVID-19). Objective: We investigated the engagement of SARS-CoV-2 with TLR4 in order to better understand how to tackle hyperinflammation in COVID-19. Methods: We combined RNA-sequencing data of human lung tissue and of bronchoalveolar lavage fluid cells derived from COVID-19 patients with functional studies in human macrophages using SARS-CoV-2 spike proteins and viable SARS-CoV-2. Pharmacological inhibitors as well as gene editing with CRISPR/Cas9 were used to delineate the signalling pathways involved. Results: We found TLR4 to be the most abundantly upregulated TLR in human lung tissue irrespective of the underlying pathology. Accordingly, bronchoalveolar lavage fluid cells from patients with severe COVID-19 showed an NF-κB-pathway dominated immune response, whereas they were mostly defined by type I interferon signalling in moderate COVID-19. Mechanistically, we found the Spike ectodomain, but not receptor binding domain monomer to induce TLR4-dependent inflammation in human macrophages. By using pharmacological inhibitors as well as CRISPR/Cas9 deleted macrophages, we identify SARS-CoV-2 to engage canonical TLR4-MyD88 signalling. Importantly, we demonstrate that TLR4 blockage prevents exaggerated inflammatory responses in human macrophages infected with different SARS-CoV-2 variants, including immune escape variants B.1.1.7.-E484K and B.1.1.529 (omicron). Conclusion: Our study critically extends the current knowledge on TLR-mediated hyperinflammatory responses to SARS-CoV-2 in human macrophages, paving the way for novel approaches to tackle severe COVID-19. Take-home message: Our study combining human lung transcriptomics with functional studies in human macrophages clearly supports the design and development of TLR4 - directed therapeutics to mitigate hyperinflammation in severe COVID-19.

HIV-1 Capsid Core: A Bullet to the Heart of the Target Cell.

The first step of the intracellular phase of retroviral infection is the release of the viral capsid core in the cytoplasm. This structure contains the viral genetic material that will be reverse transcribed and integrated into the genome of infected cells. Up to recent times, the role of the capsid core was considered essentially to protect this genetic material during the earlier phases of this process. However, increasing evidence demonstrates that the permanence inside the cell of the capsid as an intact, or almost intact, structure is longer than thought. This suggests its involvement in more aspects of the infectious cycle than previously foreseen, particularly in the steps of viral genomic material translocation into the nucleus and in the phases preceding integration. During the trip across the infected cell, many host factors are brought to interact with the capsid, some possessing antiviral properties, others, serving as viral cofactors. All these interactions rely on the properties of the unique component of the capsid core, the capsid protein CA. Likely, the drawback of ensuring these multiple functions is the extreme genetic fragility that has been shown to characterize this protein. Here, we recapitulate the busy agenda of an HIV-1 capsid in the infectious process, in particular in the light of the most recent findings.

High baseline fetuin-A levels are associated with lower atherosclerotic plaque progression as measured by 3D ultrasound.

Background and aims: The glycoprotein fetuin-A has anti-inflammatory effects, increases insulin resistance and plays an important role in calcium metabolism. The aim of our study was to assess the predictive value of fetuin-A on atherosclerotic plaque progression in comparison to the established cardiovascular biomarker high sensitivity C-reactive protein (hsCRP). Methods: In this prospective, single center-, cohort study, we included 194 patients with at least one cardiovascular risk factor or established cardiovascular disease (CVD). Over a period of 4 years, each patient underwent 3D plaque volumetry of the carotid and femoral arteries on a yearly basis. To evaluate the predictive value of biomarkers in terms of plaque progression, the baseline values of fetuin-A and hsCRP were correlated with the plaque progression from baseline to the last follow up visit. Results: 171 patients were included in the final analysis. Baseline fetuin-A levels showed a significant negative correlation with plaque progression (r = -0.244; p = 0.001). In contrast, baseline hsCRP levels showed no correlation with plaque progression (r = 0.096, p = 0.20). In the ROC-analysis, fetuin-A had a significantly better predictive value than hsCRP (fetuin-A AUC 0.67; p = 0.001 vs hsCRP AUC 0.49; p = 0.88) with an optimal cut-off value at 712 µg/ml. In patients with high fetuin A levels (>712 µg/ml), a significantly lower plaque progression was observed compared to the group with low fetuin-A levels <712 µg/ml (high fetuin-A 197 mm3 vs. low fetuin-A 279 mm3; p = 0.01). Conclusions: Higher fetuin-A levels appear to predict lower atherosclerotic plaque progression in patients with or at risk of cardiovascular disease.

NGAL Correlates with Femoral and Carotid Plaque Volume Assessed by Sonographic 3D Plaque Volumetry.

BACKGROUND/OBJECTIVES: Inflammation represents a cornerstone in the development of atherosclerosis and early detection is essential to avoid cardiovascular events. Biomarkers like interleukin-1 beta, interleukin-6, or high sensitivity CRP (hs-CRP) have been investigated intensively in this field. Since they have several limitations, additional biomarkers are needed for cardiovascular risk stratification. The acute phase protein, neutrophil gelatinase-associated lipocalin (NGAL), modulates inflammation and is elevated in cardiovascular disease (CVD). Moreover, it contributes to plaque destabilization. METHODS: In this prospective, single-center study, we included 323 asymptomatic patients with at least one cardiovascular risk factor or established CVD. NGAL levels were measured in plasma samples using a commercially available ELISA. Carotid, femoral, and total atherosclerotic plaque volumes (PV) were measured using a 3D ultrasound system (Philips iU22). Patients were separated into a low (n = 243) and high (n = 80) total PV group. RESULTS: NGAL was significantly higher in patients with high total PV versus patients with low total PV. The NGAL amplitude for the prediction of high total PV was significantly higher when compared with hs-CRP. A high predictive value could also be observed for patients without established CVD. CONCLUSION: NGAL seems to be a promising biomarker for the identification of asymptomatic patients with atherosclerotic disease.

Early onset of menopause is associated with increased peripheral atherosclerotic plaque volume and progression.

BACKGROUND AND AIMS: Cardiovascular disease (CVD) is the leading cause of death in western countries. One risk factor unique to women is the menopausal status. The aim of this study was to analyse the influence of the onset of menopause (MP) on the extent and progression of atherosclerotic plaque volume (PV). METHODS: Postmenopausal women with at least one cardiovascular risk factor (CVRF) but without established CVD were included. Quantification of PV was performed in peripheral arteries using a three - dimensional (3D) ultrasound (US) technique. Follow-up examination to assess PV progression was performed after 19 (±8) months. RESULTS: 110 consecutive postmenopausal women (mean age 65.5) were included. Females with an earlier onset of MP (<45 years) had a significantly higher PV than those with an intermediate (45-52 years) or later onset of menopause (>52 years), irrespective of other CVRF (244 mm³ vs. 193 mm³ vs. 73 mm³, respectively, p = 0.023). In addition, women with an earlier onset of MP had a higher PV progression compared to women with an intermediate or late onset (40 mm³ vs. 35 mm³ vs. 8.5 mm³; p = 0.002, respectively). Moreover, these results were confirmed in multivariate regression, where only onset of MP (OR 0.88; 95%CI 0.81-0.96; p = 0.004) and age (OR 1.06; 95%CI 1.08-1.13; p = 0.025) were significant predictors for a higher atherosclerotic progression. CONCLUSIONS: An earlier onset of MP was associated with an increase in atherosclerotic PV and accelerated progression, independent of other CVRF.

High-resolution NMR analysis of the conformations of native and base analog substituted retroviral and LTR-retrotransposon PPT primers.

A purine-rich region of the plus-strand RNA genome of retroviruses and long terminal repeat (LTR)-containing retrotransposons, known as the polypurine tract (PPT), is resistant to hydrolysis by the RNase H domain of reverse transcriptase (RT) and ultimately serves as a primer for plus-strand DNA synthesis. The mechanisms underlying PPT resistance and selective processing remain largely unknown. Here, two RNA/DNA hybrids derived from the PPTs of HIV-1 and Ty3 were probed using high-resolution NMR for preexisting structural distortions in the absence of RT. The PPTs were selectively modified through base-pair changes or by incorporation of the thymine isostere, 2,4-difluoro-5-methylbenzene (dF), into the DNA strand. Although both wild-type (WT) and mutated hybrids adopted global A-form-like helical geometries, observed structural perturbations in the base-pair and dF-modified hybrids suggested that the PPT hybrids may function as structurally coupled domains.

Sitagliptin Accelerates Endothelial Regeneration after Vascular Injury Independent from GLP1 Receptor Signaling.

INTRODUCTION: DPP4 inhibitors (gliptins) are commonly used antidiabetic drugs for the treatment of type 2 diabetes. Gliptins also act in a glucose-independent manner and show vasoregenerative effects. We have shown that gliptins can remarkably accelerate vascular healing after vascular injury. However, the underlying mechanisms remain unclear. Here, we examined potential signaling pathways linking gliptins to enhanced endothelial regeneration. METHODS AND RESULTS: We used wild-type and GLP1 receptor knockout (Glp1r-/-) mice to investigate the underlying mechanisms of gliptin-induced reendothelialization. The prototype DPP4 inhibitor sitagliptin accelerated endothelial healing in both animal models. Improved endothelial growth was associated with gliptin-mediated progenitor cell recruitment into the diseased vascular wall via the SDF1-CXCR4 axis independent of GLP1R-dependent signaling pathways. Furthermore, SDF1 showed direct proproliferative effects on endothelial cells. Excessive neointimal formation was not observed in gliptin- or placebo-treated Glp1r-/- mice. CONCLUSION: We identified the SDF1-CXCR4 axis as a crucial signaling pathway for endothelial regeneration after acute vascular injury. Furthermore, SDF1 can directly increase endothelial cell proliferation. Gliptin-mediated potentiation of endothelial regeneration was preserved in Glp1r-/- animals. Thus, gliptin-mediated endothelial regeneration proceeds through SDF-1/CXCR4 in a GLP1R-independent manner after acute vascular injury.