Measuring algorithmically infused societies.

It has been the historic responsibility of the social sciences to investigate human societies. Fulfilling this responsibility requires social theories, measurement models and social data. Most existing theories and measurement models in the social sciences were not developed with the deep societal reach of algorithms in mind. The emergence of 'algorithmically infused societies'-societies whose very fabric is co-shaped by algorithmic and human behaviour-raises three key challenges: the insufficient quality of measurements, the complex consequences of (mis)measurements, and the limits of existing social theories. Here we argue that tackling these challenges requires new social theories that account for the impact of algorithmic systems on social realities. To develop such theories, we need new methodologies for integrating data and measurements into theory construction. Given the scale at which measurements can be applied, we believe measurement models should be trustworthy, auditable and just. To achieve this, the development of measurements should be transparent and participatory, and include mechanisms to ensure measurement quality and identify possible harms. We argue that computational social scientists should rethink what aspects of algorithmically infused societies should be measured, how they should be measured, and the consequences of doing so.

Publisher Correction: Actively personalized vaccination trial for newly diagnosed glioblastoma.

The additional author support information was erroneously omitted from the Supplementary Information. This has been corrected online.

Actively personalized vaccination trial for newly diagnosed glioblastoma.

Patients with glioblastoma currently do not sufficiently benefit from recent breakthroughs in cancer treatment that use checkpoint inhibitors1,2. For treatments using checkpoint inhibitors to be successful, a high mutational load and responses to neoepitopes are thought to be essential3. There is limited intratumoural infiltration of immune cells4 in glioblastoma and these tumours contain only 30-50 non-synonymous mutations5. Exploitation of the full repertoire of tumour antigens-that is, both unmutated antigens and neoepitopes-may offer more effective immunotherapies, especially for tumours with a low mutational load. Here, in the phase I trial GAPVAC-101 of the Glioma Actively Personalized Vaccine Consortium (GAPVAC), we integrated highly individualized vaccinations with both types of tumour antigens into standard care to optimally exploit the limited target space for patients with newly diagnosed glioblastoma. Fifteen patients with glioblastomas positive for human leukocyte antigen (HLA)-A*02:01 or HLA-A*24:02 were treated with a vaccine (APVAC1) derived from a premanufactured library of unmutated antigens followed by treatment with APVAC2, which preferentially targeted neoepitopes. Personalization was based on mutations and analyses of the transcriptomes and immunopeptidomes of the individual tumours. The GAPVAC approach was feasible and vaccines that had poly-ICLC (polyriboinosinic-polyribocytidylic acid-poly-L-lysine carboxymethylcellulose) and granulocyte-macrophage colony-stimulating factor as adjuvants displayed favourable safety and strong immunogenicity. Unmutated APVAC1 antigens elicited sustained responses of central memory CD8+ T cells. APVAC2 induced predominantly CD4+ T cell responses of T helper 1 type against predicted neoepitopes.

SARS-CoV-2-reactive T-cell receptors isolated from convalescent COVID-19 patients confer potent T-cell effector function.

Both B cells and T cells are involved in an effective immune response to SARS-CoV-2, the disease-causing virus of COVID-19. While B cells-with the indispensable help of CD4+ T cells-are essential to generate neutralizing antibodies, T cells on their own have been recognized as another major player in effective anti-SARS-CoV-2 immunity. In this report, we provide insights into the characteristics of individual HLA-A*02:01- and HLA-A*24:02-restricted SARS-CoV-2-reactive TCRs, isolated from convalescent COVID-19 patients. We observed that SARS-CoV-2-reactive T-cell populations were clearly detectable in convalescent samples and that TCRs isolated from these T cell clones were highly functional upon ectopic re-expression. The SARS-CoV-2-reactive TCRs described in this report mediated potent TCR signaling in reporter assays with low nanomolar EC50 values. We further demonstrate that these SARS-CoV-2-reactive TCRs conferred powerful T-cell effector function to primary CD8+ T cells as evident by a robust anti-SARS-CoV-2 IFN-γ response and in vitro cytotoxicity. We also provide an example of a long-lasting anti-SARS-CoV-2 memory response by reisolation of one of the retrieved TCRs 5 months after initial sampling. Taken together, these findings contribute to a better understanding of anti-SARS-CoV-2 T-cell immunity and may contribute to paving the way toward immunotherapeutics approaches targeting SARS-CoV-2.

Micro-organisms growing on rapeseed during storage affect the profile of volatile compounds of virgin rapeseed oil.

BACKGROUND: Micro-organisms populate on rapeseed after harvest during storage depending on the growing conditions. The composition of the bacterial colonization is unknown, although its contribution to the profile of volatile aroma-active compounds determines the sensory quality of virgin cold-pressed rapeseed oil. RESULTS: From four rapeseed samples, 46 bacterial strains were isolated. By DNA-sequencing, the identification of four bacteria species and 17 bacteria genera was possible. In total, 22 strains were selected, based on their typical off-flavors resembling those of virgin sensory bad cold-pressed rapeseed oils. The cultivation of these strains on rapeseed meal agar and examination of volatile compounds by solid phase microextraction-gas chromatography-mass spectrometry allowed the identification of 29 different compounds, mainly degradation products of fatty acids such as alkanes, alkenes, aldehydes, ketones and alcohols and, in addition, sulfur-containing compounds, including one terpene and three pyrazines. From these compounds, 19 are described as aroma-active in the literature. CONCLUSION: Micro-organisms populating on rapeseed during storage may strongly influence the sensory quality of virgin rapeseed oil as a result of the development of volatile aroma-active metabolic products. It can be assumed that occurrence of off-flavor of virgin rapeseed oils on the market are the result of metabolic degradation products produced by micro-organisms populating on rapeseed during storage. © 2017 Society of Chemical Industry.

IMA901, a multipeptide cancer vaccine, plus sunitinib versus sunitinib alone, as first-line therapy for advanced or metastatic renal cell carcinoma (IMPRINT): a multicentre, open-label, randomised, controlled, phase 3 trial.

BACKGROUND: In a phase 2 study in patients with metastatic renal cell carcinoma, overall survival was associated with T-cell responses against IMA901, a vaccine consisting of ten tumour-associated peptides. In this phase 3 trial, we aimed to determine the clinical effect of adding IMA901 to sunitinib, the standard first-line treatment in metastatic renal cell carcinoma with postulated favourable immunomodulatory effects. METHODS: The IMPRINT study is an open-label, randomised, controlled, phase 3 trial done at 124 clinical sites in 11 countries. HLA-A*02-positive patients (aged ≥18 years) with treatment-naive, histologically confirmed metastatic or locally advanced (or both) clear-cell renal cell carcinoma were randomly assigned (3:2) to receive sunitinib plus up to ten intradermal vaccinations of IMA901 (4·13 mg) and granulocyte macrophage colony-stimulating factor (75 µg), with one dose of cyclophosphamide (300 mg/m2) 3 days before the first vaccination, or to receive sunitinib alone. Sunitinib (50 mg) was given orally once daily, with each cycle defined as 4 weeks on treatment followed by 2 weeks off treatment, until progression of disease as determined by the investigator, death, or withdrawal of consent. Block randomisation (block size five) was done centrally using an interactive web response system, stratified by prognostic risk, geographical region, and previous nephrectomy. Patients and investigators were not masked to treatment allocation. The primary endpoint was overall survival from randomisation until death of any cause as determined by the investigator, analysed by intention to treat. This study is registered with ClinicalTrials.gov, number NCT01265901. FINDINGS: Between Dec 22, 2010, and Dec 15, 2012, we screened 1171 patients, of whom 339 were randomly assigned to receive sunitinib plus IMA901 (n=204) or sunitinib monotherapy (n=135). Patients had a median follow-up of 33·27 months (IQR 29·92-35·64). Median overall survival did not differ significantly between the groups (33·17 months [95% CI 27·81-41·36] in the sunitinib plus IMA901 group vs not reached [33·67-not reached] in the sunitinib monotherapy group; hazard ratio 1·34 [0·96-1·86]; p=0·087). 116 (57%) of 202 patients in the sunitinib plus IMA901 group and 62 (47%) of 132 in the sunitinib group had grade 3 or worse adverse events, the most common of which were hypertension, neutropenia, and anaemia in both groups, and mild-to-moderate transient injection-site reactions (eg, erythema, pruritus) were the most frequent IMA901-related side-effect in the sunitinib plus IMA901 group. Serious adverse events leading to death occurred in four (2%) patients (one respiratory failure and circulatory collapse [possibly related to sunitinib], one oesophageal varices haemorrhage [possibly related to sunitinib], one cardiac arrest [possibly related to sunitinib], and one myocardial infarction) and eight (6%) patients in the sunitinib group (one case each of renal failure, oesophageal varices haemorrhage, circulatory collapse, wound infection, ileus, cerebrovascular accident [possibly treatment related], and sepsis). INTERPRETATION: IMA901 did not improve overall survival when added to sunitinib as first-line treatment in patients with metastatic renal cell carcinoma. The magnitude of immune responses needs to be improved before further development of IMA901 in this disease is indicated. FUNDING: Immatics Biotechnologies.

TLR and nucleotide-binding oligomerization domain-like receptor signals differentially regulate exogenous antigen presentation.

The effect of dendritic cell (DC) maturation on MHC class II-restricted Ag presentation is well studied, but less is known about the effects of DC maturation on MHC class I-restricted cross-presentation. We investigated the ability of mature DCs to present Ags from cells infected with HSV-1. Pretreatment with pure LPS increased cross-presentation in a manner dependent on both MyD88 and Toll/IL-1R domain-containing adaptor inducing IFN-ß, whereas a similar dose of a less pure LPS preparation inhibited cross-presentation. The difference could not be attributed to differences in uptake or phenotypic maturation. The likely contaminant responsible for shutting down cross-presentation is peptidoglycan (PGN). Addition of PGN to pure LPS abrogated its ability to enhance cross-presentation. Direct activation of DCs with PGN inhibited cross-presentation through nucleotide-binding oligomerization domain-like receptor signaling. These results demonstrate that different maturation stimuli can have opposite impacts on the ability of DCs to cross-present viral Ags.

AI Psychometrics: Assessing the Psychological Profiles of Large Language Models Through Psychometric Inventories.

We illustrate how standard psychometric inventories originally designed for assessing noncognitive human traits can be repurposed as diagnostic tools to evaluate analogous traits in large language models (LLMs). We start from the assumption that LLMs, inadvertently yet inevitably, acquire psychological traits (metaphorically speaking) from the vast text corpora on which they are trained. Such corpora contain sediments of the personalities, values, beliefs, and biases of the countless human authors of these texts, which LLMs learn through a complex training process. The traits that LLMs acquire in such a way can potentially influence their behavior, that is, their outputs in downstream tasks and applications in which they are employed, which in turn may have real-world consequences for individuals and social groups. By eliciting LLMs' responses to language-based psychometric inventories, we can bring their traits to light. Psychometric profiling enables researchers to study and compare LLMs in terms of noncognitive characteristics, thereby providing a window into the personalities, values, beliefs, and biases these models exhibit (or mimic). We discuss the history of similar ideas and outline possible psychometric approaches for LLMs. We demonstrate one promising approach, zero-shot classification, for several LLMs and psychometric inventories. We conclude by highlighting open challenges and future avenues of research for AI Psychometrics.

Cardioprotection by ischemic postconditioning is abrogated in hypertrophied myocardium of spontaneously hypertensive rats.

PURPOSE: This study examines if ischemic postconditioning is preserved in hypertrophied myocardium of spontaneously hypertensive rats (SHR). METHODS: Infarct sizes, hemodynamic, morphometric, and biochemical parameters were obtained from normotensive controls [Wistar-Kyoto (WKY) rats] and compared with SHRs. In open-chest rats, the infarct size was determined after 30 minutes of regional ischemia. Postconditioning was performed by 3 cycles of ischemia/reperfusion with 30 seconds each or 6 cycles of ischemia/reperfusion with 10 seconds each immediately after the infarction. RESULTS: Infarct size was comparable between control rats and SHRs. In WKY rats, postconditioning reduced the infarct size significantly. However, in SHRs, the postconditioning effect was completely lost for both postconditioning protocols. Even shortening of the ischemic period to 20 minutes did not restore the infarct sparing effect in SHRs. The phosphorylation of glycogen synthase kinase 3ß increased 2.1-fold by ischemic postconditioning in WKY rats; however, this increase was completely absent in SHRs with both postconditioning protocols. CONCLUSIONS: Myocardial hypertrophy inhibits the protection by postconditioning in an experimental animal model. Future studies have to clarify whether this result can be extrapolated to patients with arterial hypertension and myocardial hypertrophy.

An ultra-high-throughput screen for the evaluation of peptide HLA-Binder interactions.

Peptide human leukocyte antigen (pHLA) targeting therapeutics like T-cell receptor based adoptive cell therapy or bispecific T cell engaging receptor molecules hold great promise for the treatment of cancer. Comprehensive pre-clinical screening of therapeutic candidates is important to ensure patient safety but is challenging because of the size of the potential off-target space. By combining stabilized peptide-receptive HLA molecules with microarray printing and screening, we have developed an ultra-high-throughput screening platform named ValidaTe that enables large scale evaluation of pHLA-binder interactions. We demonstrate its potential by measuring and analyzing over 30.000 binding curves for a high-affinity T cell Engaging Receptor towards a large pHLA library. Compared to a dataset obtained by conventional bio-layer interferometry measurements, we illustrate that a massively increased throughput (over 650 fold) is obtained by our microarray screening, paving the way for use in pre-clinical safety screening of pHLA-targeting drugs.

Feasibility and Safety of Personalized, Multi-Target, Adoptive Cell Therapy (IMA101): First-in-Human Clinical Trial in Patients with Advanced Metastatic Cancer.

IMA101 is an actively personalized, multi-targeted adoptive cell therapy (ACT), whereby autologous T cells are directed against multiple novel defined peptide-HLA (pHLA) cancer targets. HLA-A*02:01-positive patients with relapsed/refractory solid tumors expressing ≥1 of 8 predefined targets underwent leukapheresis. Endogenous T cells specific for up to 4 targets were primed and expanded in vitro. Patients received lymphodepletion (fludarabine, cyclophosphamide), followed by T-cell infusion and low-dose IL2 (Cohort 1). Patients in Cohort 2 received atezolizumab for up to 1 year (NCT02876510). Overall, 214 patients were screened, 15 received lymphodepletion (13 women, 2 men; median age, 44 years), and 14 were treated with T-cell products. IMA101 treatment was feasible and well tolerated. The most common adverse events were cytokine release syndrome (Grade 1, n = 6; Grade 2, n = 4) and expected cytopenias. No patient died during the first 100 days after T-cell therapy. No neurotoxicity was observed. No objective responses were noted. Prolonged disease stabilization was noted in three patients lasting for 13.7, 12.9, and 7.3 months. High frequencies of target-specific T cells (up to 78.7% of CD8+ cells) were detected in the blood of treated patients, persisted for >1 year, and were detectable in posttreatment tumor tissue. Individual T-cell receptors (TCR) contained in T-cell products exhibited broad variation in TCR avidity, with the majority being low avidity. High-avidity TCRs were identified in some patients' products. This study demonstrates the feasibility and tolerability of an actively personalized ACT directed to multiple defined pHLA cancer targets. Results warrant further evaluation of multi-target ACT approaches using potent high-avidity TCRs. See related Spotlight by Uslu and June, p. 865.

Inequality and inequity in network-based ranking and recommendation algorithms.

Though algorithms promise many benefits including efficiency, objectivity and accuracy, they may also introduce or amplify biases. Here we study two well-known algorithms, namely PageRank and Who-to-Follow (WTF), and show to what extent their ranks produce inequality and inequity when applied to directed social networks. To this end, we propose a directed network model with preferential attachment and homophily (DPAH) and demonstrate the influence of network structure on the rank distributions of these algorithms. Our main findings suggest that (i) inequality is positively correlated with inequity, (ii) inequality is driven by the interplay between preferential attachment, homophily, node activity and edge density, and (iii) inequity is driven by the interplay between homophily and minority size. In particular, these two algorithms reduce, replicate and amplify the representation of minorities in top ranks when majorities are homophilic, neutral and heterophilic, respectively. Moreover, when this representation is reduced, minorities may improve their visibility in the rank by connecting strategically in the network. For instance, by increasing their out-degree or homophily when majorities are also homophilic. These findings shed light on the social and algorithmic mechanisms that hinder equality and equity in network-based ranking and recommendation algorithms.

Inequality and fairness with heterogeneous endowments.

People differ in intelligence, cognitive ability, personality traits, motivation, and similar valued and, to a large degree, inherited characteristics that determine success and achievements. When does individual heterogeneity lead to a fair distribution of rewards and outcomes? Here, we develop this question theoretically and then test it experimentally for a set of structural conditions in a specific interaction situation. We first catalogue the functional relationship between individual endowments and outcomes to distinguish between fairness concepts such as meritocracy, equality of opportunity, equality of outcomes, and Rawl's theory of justice. We then use an online experiment to study which of these fairness patterns emerge when differently endowed individuals can share their resources with others, depending on whether information about others' endowments and outcomes is available. We find that while visible outcomes lessen inequality by decreasing the statistical dispersion of outcomes across the group, endowments need to be visible for better equality of opportunity for the most disadvantaged.

Quantitative immunopeptidomics reveals a tumor stroma-specific target for T cell therapy.

T cell receptor (TCR)-based immunotherapy has emerged as a promising therapeutic approach for the treatment of patients with solid cancers. Identifying peptide-human leukocyte antigen (pHLA) complexes highly presented on tumors and rarely expressed on healthy tissue in combination with high-affinity TCRs that when introduced into T cells can redirect T cells to eliminate tumor but not healthy tissue is a key requirement for safe and efficacious TCR-based therapies. To discover promising shared tumor antigens that could be targeted via TCR-based adoptive T cell therapy, we employed population-scale immunopeptidomics using quantitative mass spectrometry across ~1500 tumor and normal tissue samples. We identified an HLA-A*02:01-restricted pan-cancer epitope within the collagen type VI α-3 (COL6A3) gene that is highly presented on tumor stroma across multiple solid cancers due to a tumor-specific alternative splicing event that rarely occurs outside the tumor microenvironment. T cells expressing natural COL6A3-specific TCRs demonstrated only modest activity against cells presenting high copy numbers of COL6A3 pHLAs. One of these TCRs was affinity-enhanced, enabling transduced T cells to specifically eliminate tumors in vivo that expressed similar copy numbers of pHLAs as primary tumor specimens. The enhanced TCR variants exhibited a favorable safety profile with no detectable off-target reactivity, paving the way to initiate clinical trials using COL6A3-specific TCRs to target an array of solid tumors.

Chitin induces upregulation of B7-H1 on macrophages and inhibits T-cell proliferation.

Chitin is a highly abundant glycopolymer, which serves as structural component in fungi, arthropods and crustaceans but is not synthesized by vertebrates. However, vertebrates express chitinases and chitinase-like proteins, some of which are induced by infection with helminths suggesting that chitinous structures may be targets of the immune system. The chitin-induced modulations of the innate and adaptive immune responses are not well understood. Here, we demonstrate that intranasal administration of OVA and chitin resulted in diminished T-cell expansion and Th2 polarization as compared with OVA administration alone. Chitin did not promote nor attenuate Th2 polarization in vitro. Chitin-exposed macrophages inhibited proliferation of CD4(+) T cells in a cell-cell contact-dependent manner. Chitin induced upregulation of the inhibitory ligand B7-H1 (PD-L1) on macrophages independently of MyD88, TRIF, TLR2, TLR3, TLR4 and Stat6. Inhibition of T-cell proliferation was largely dependent on B7-H1, as the effect was not observed in cocultures with cells from B7-H1-deficient mice.

Monte Carlo computer simulations and electron microscopy of colloidal cluster formation via emulsion droplet evaporation.

We consider a theoretical model for a binary mixture of colloidal particles and spherical emulsion droplets. The hard sphere colloids interact via additional short-ranged attraction and long-ranged repulsion. The droplet-colloid interaction is an attractive well at the droplet surface, which induces the Pickering effect. The droplet-droplet interaction is a hard-core interaction. The droplets shrink in time, which models the evaporation of the dispersed (oil) phase, and we use Monte Carlo simulations for the dynamics. In the experiments, polystyrene particles were assembled using toluene droplets as templates. The arrangement of the particles on the surface of the droplets was analyzed with cryogenic field emission scanning electron microscopy. Before evaporation of the oil, the particle distribution on the droplet surface was found to be disordered in experiments, and the simulations reproduce this effect. After complete evaporation, ordered colloidal clusters are formed that are stable against thermal fluctuations. Both in the simulations and with field emission scanning electron microscopy, we find stable packings that range from doublets, triplets, and tetrahedra to complex polyhedra of colloids. The simulated cluster structures and size distribution agree well with the experimental results. We also simulate hierarchical assembly in a mixture of tetrahedral clusters and droplets, and find supercluster structures with morphologies that are more complex than those of clusters of single particles.

Plasma pharmacokinetics and gastrointestinal transit of a new propionyl-L-carnitine controlled release formulation.

Propionyl-L-carnitine is a naturally occurring analogue of L-carnitine (LC) produced in the body. PLC administration has shown beneficial effects in cardiovascular pathologies. In ulcerative colitis (UC), oral PLC treatment increased clinical presentation and positively influenced colon histology. In the present study, the MMX Multi Matrix System® (MMX™) was used as drug delivery strategy for targeted PLC colon delivery. A pharmacoscintigraphic study (n = 6 healthy volunteers) described release characteristics of two MMX-PLC-HCl controlled release 500 mg tablets. A pharmacokinetic (PK) parallel group study (n = 24) determined safety, plasma PLC concentrations and PK parameters after single and multiple doses. Gastrointestinal transit was slow and variable. The colon was the main site of PLC release and absorption. After single 500 or 1000 mg PLC doses plasma PLC and LC increased up to 2.6 and 1.2-1.3-fold compared to baseline. Multiple doses of 500 and 1000 mg twice a day over 7 days did not significantly increase maximum plasma concentrations of PLC or LC with respect to concentrations achieved after single dose administration. The colon is the main site of PLC release and absorption from MMX-PLC tablets. A daily dose of 500 mg to 1000 mg PLC twice a day was well tolerated, justifying further studies in patients with pathologies of the distal gastrointestinal tract to evaluate the efficacy of the MMX-PLC formulation.

Postconditioning with levosimendan reduces the infarct size involving the PI3K pathway and KATP-channel activation but is independent of PDE-III inhibition.

Reperfusion injury is strongly involved in the loss of functional heart tissue in patients after acute myocardial infarction. Various signal transduction pathways to reduce infarct size during reperfusion have been characterized. However, so far in the clinical setting no standard therapies are applied due to the lack of suitable drugs. Levosimendan, a calcium sensitizer, has been shown to improve survival in cardiogenic shock after infarction. Focus of the present study was to address the question, whether a bolus application of levosimendan prior to reperfusion is able to reduce the infarct size. A well-characterized model, the in vivo rat model, was used and levosimendan applied 5 min prior to reperfusion after 30-min occlusion of the left coronary artery followed by a 30-min reperfusion period. This pharmacological postconditioning was compared to the ischemic postconditioning with three times occlusion/reperfusion periods of 30 s each. To further address the question if in this in vivo model the phosphatidylinositol 3-kinase (PI3K) pathway may be involved, the PDE-III inhibiting property of levosimendan was compared to the PDE-III inhibitor enoximone. Ischemic postconditioning significantly reduced the infarct size from 48 +/- 2 to 32 +/- 1% of the area at risk (P < 0.05). Similarly, levosimendan decreased infarct size down to 29 +/- 3%. The combination of ischemic postconditioning and pharmacological postconditioning using levosimendan did not result in a further reduction of the infarct size. Both, the mitochondrial KATP-channel blocker 5-hydroxydecanoate (5-HD) and the PI3K inhibitor wortmannin abolished the protection afforded by levosimendan completely, while the inhibitors alone did not influence the infarct size in control hearts. Pharmacological postconditioning with enoximone did not result in any infarct size reduction. Postconditioning with levosimendan significantly increased the phosphorylation of protein kinase B (Akt) and glycogen synthase kinase-3beta (GSK-3beta) at 5 min of reperfusion, an effect which could be blocked completely by the additional administration of wortmannin. In conclusion, levosimendan applied prior to reperfusion in acute myocardial infarction significantly reduces the infarct size in an in vivo rat model. This protection involves the PI3K pathway and the activation of mitochondrial KATP-channels, but is independent of PDE-III inhibition. This finding may open new possibilities for the treatment of patients with acute myocardial infarction using levosimendan, which is an already established therapy in cardiogenic shock. Whether the reduction of mortality in cardiogenic shock by levosimendan may in part be based on this postconditioning effect remains to be elucidated in clinical setting.

Forearm vasodilator reactivity in homozygous carriers of the 9p21.3 rs1333049 G>C polymorphism.

AIM: Recently, a novel susceptibility locus for coronary artery disease (CAD) has been identified on chromosome 9p21.3, linked to the single-nucleotide polymorphism (SNP) rs1333049 G>C. However, the physiological mechanism through which this locus confers an increased CAD-risk is still unknown. The aim of the present case-control study was to test whether this chromosome 9p21.3 locus, represented by the rs1333049 variant, is associated with altered vasodilator resistance vessel function in healthy young volunteers. DESIGN AND RESULTS: A total of 97 healthy male volunteers were screened for homozygous carriers of either the G- or the C-allele, the minor allele in European populations. Forearm blood flow (FBF) reactivity to acetylcholine (ACh) and glycerol trinitrate (GTN) was then studied in 10 C/C-genotype carriers compared with 10 control subjects harbouring the G/G-genotype. FBF responses to ACh and GTN were reduced in subjects homozygous for the C-allele of the rs1333049 SNP (P < 0.05). FBF reactivity to the highest dose of ACh and GTN was 95% and 74% lower when compared with control subjects with the G/G-genotype. CONCLUSION: Our study revealed a functional impairment in forearm artery vasodilator resistance in carriers of the rs1333049 C/C-genotype, thus providing evidence for a first physiological functional link underlying the genetic association of the 9p21.3 locus with an increased cardiovascular risk.

Ischemic post-conditioning reduces infarct size of the in vivo rat heart: role of PI3-K, mTOR, GSK-3beta, and apoptosis.

Post-conditioning by repetitive cycles of reperfusion/ischemia after prolonged ischemia protects the heart from infarction. The objectives of this study were: Are kinases (PI3-kinase, mTOR, and GSK-3beta) involved in the signaling pathway of post-conditioning? Does post-conditioning result in a diminished necrosis or apoptosis? In open chest rats the infarct size was determined after 30 min of regional ischemia and 30 min of reperfusion using propidium iodide and microspheres. Post-conditioning was performed by three cycles of 30 s reperfusion and reocclusion each, immediately upon reperfusion. PI3-kinase and mTOR were blocked using wortmannin (0.6 mg/kg) or rapamycin (0.25 mg/kg), respectively. The phosphorylation of GSK-3beta and p70S6K was determined with phospho-specific antibodies. TUNEL staining and detection of apoptosis-inducing factor (AIF) were used for the determination of apoptosis. Control hearts had an infarct size of 49 +/- 3%, while post-conditioning significantly reduced it to 29 +/- 3% (P < 0.01). Wortmannin as well as rapamycin completely blocked the infarct size reduction of post-conditioning (51 +/- 2% and 54 +/- 5%, respectively). Western blot analysis revealed that post-conditioning increased the phosphorylation of GSK-3beta by 2.3 times (P < 0.01), and this increase could be blocked by wortmannin, a PI3-kinase inhibitor. Although rapamycin blocked the infarct size reduction, phosphorylation of p70S6K was not increased in post-conditioned hearts. After 2 h of reperfusion, the post-conditioned hearts had significantly fewer TUNEL-positive nuclei (35 %) compared to control hearts (53%; P < 0.001). AIF was equally reduced in post-conditioned rat hearts (P < 0.05 vs. control). Infarct size reduction by ischemic post-conditioning of the in vivo rat heart is PI3-kinase dependent and involves mTOR. Furthermore, GSK-3beta, which is thought to be a regulator of the mPTP, is part of the signaling pathway of post-conditioning. Finally, apoptosis was inhibited by post-conditioning, which was shown by two independent methods. The role of apoptosis and/or autophagy in post-conditioning has to be further elucidated to find therapeutic targets to protect the heart from the consequences of acute myocardial infarction.