A multi-ancestry genome-wide study incorporating gene-smoking interactions identifies multiple new loci for pulse pressure and mean arterial pressure

Elevated blood pressure (BP), a leading cause of global morbidity and mortality, is influenced by both genetic and lifestyle factors. Cigarette smoking is one such lifestyle factor. Across five ancestries, we performed a genome-wide gene-smoking interaction study of mean arterial pressure (MAP) and pulse pressure (PP) in 129 913 individuals in stage 1 and follow-up analysis in 480 178 additional individuals in stage 2. We report here 136 loci significantly associated with MAP and/or PP. Of these, 61 were previously published through main-effect analysis of BP traits, 37 were recently reported by us for systolic BP and/or diastolic BP through gene-smoking interaction analysis and 38 were newly identified (P <5 x 10(-8), false discovery rate <0.05). We also identified nine new signals near known loci. Of the 136 loci, 8 showed significant interaction with smoking status. They include CSMD1 previously reported for insulin resistance and BP in the spontaneously hypertensive rats. Many of the 38 new loci show biologic plausibility for a role in BP regulation. SLC26A7 encodes a chloride/bicarbonate exchanger expressed in the renal outer medullary collecting duct. AVPR1A is widely expressed, including in vascular smooth muscle cells, kidney, myocardium and brain. FHAD1 is a long non-coding RNA overexpressed in heart failure. TMEM51 was associated with contractile function in cardiomyocytes. CASP9 plays a central role in cardiomyocyte apoptosis. Identified only in African ancestry were 30 novel loci. Our findings highlight the value of multi-ancestry investigations, particularly in studies of interaction with lifestyle factors, where genomic and lifestyle differences may contribute to novel findings.Peer reviewe

experiments in temporal cortex slices of patients suffering from chronic epilepsy

Pharmakoresistenz ist in der Behandlung fokaler Epilepsien ein häufiges Phänomen. Die genauen Mechanismen sind wenig verstanden und Gegenstand aktueller Forschungsansätze. Es wird danach gefragt, ob die Wirkung der Antikonvulsiva durch Veränderungen an ihren Zielstrukturen (Target-Hypothese) herabgesetzt ist und ob ATP-abhängige Drug-Transporter an der Blut-Hirn- Schranke bzw. im Hirnparenchym verhindern, dass sich Antikonvulsiva bis zu einer therapeutisch wirksamen Konzentration im Gewebe anreichern (Transporter- Hypothese). Epilepsie-chirurgisch entferntes, epileptogenes und pharmakoresistentes Hirngewebe bietet die Möglichkeit, direkt in den erkrankten Hirnregionen nach Faktoren der Pharmakoresistenz zu suchen. In vorangegangenen Studien wurde gezeigt, dass in Gewebeschnitten aus Hippokampus-Resektaten im Gyrus dentatus epileptiforme Aktivität ausgelöst werden kann. Diese in-vitro-Aktivität ließ sich in Resektaten von Patienten, die tumorbedingt nur kurze Zeit an Epilepsien litten, durch das Antikonvulsivum Carbamazepin unterdrücken. Im Gegensatz dazu war die Aktivität in 80 % der Resektate von Patienten mit langdauernder mesialer Temporallappen- Epilepsie resistent gegenüber Carbamazepin. Da im angewandten Modell eine antikonvulsive Behandlung des Gewebes unter Umgehung der Blut-Hirn-Schranke gewährleistet war, ließ sich schlussfolgern, dass parenchymal lokalisierte Mechanismen zur Pharmakoresistenz im Gyrus dentatus beitragen. In der vorliegenden Arbeit sollte an Resektaten des vorderen Temporalpols (TP) getestet werden ob a) in Gewebeschnitten des resezierten temporalen Kortex stabile, epileptiforme Aktivität auslösbar ist, b) die induzierte Aktivität auf die in der antiepileptischen Monotherapie erprobten Antikonvulsiva Carbamazepin, Valproat und Phenytoin reagiert, c) die zusätzliche Hemmung der ektop exprimierten Multidrug-Transporter Pgp und MRP mit Verapamil (VPM) und Probenecid (PBN) die Pharmakoresistenz des Gewebes aufheben kann und d) sich eigene Effekte der Multidrugtransport-Inhibitoren (MDTI) VPM und PBN auf die epileptiforme Aktivität nachweisen lassen. Mit dem Hochkalium-Bicucullin- Modell (Perfusion der Gewebeschnitte mit 8 mM [K+]- und 50 µM Bicucullin-ACSF) kann in 85% von 166 Gewebeschnitten periodische epileptiforme Aktivität induziert werden. Diese Aktivität ist durch eine Folge krampf-artiger oder spike-artiger Ereignisse charakterisiert (121 bzw. 20 Gewebeschnitte), wird durch AMPA-/Kainat-Rezeptoren vermittelt und bleibt ohne Gabe von Medikamenten bis zu 80 Minuten stabil. In 37 Gewebeschnitten von Patienten mit klar definierter Kortexpathologie ist die spike-artige Aktivität häufiger zu beobachten (38%) als in 95 Gewebeschnitten von Patienten mit pathologisch „unauffälligem“ Kortex (6%). Das Muster der krampf-artigen Aktivität wird durch die Antikonvulsiva (AED) Carbamazepin (CBZ), Valproat (VPA) und Phenytoin (PHT) überwiegend nicht verändert (81% von 76 Gewebeschnitten). Die Multidrugtransporter-Inhibitoren (MDTI) Verapamil (VPM) und Probenecid (PBN) bewirken in einem Teil der Gewebeschnitte eine Veränderung des Aktivitätstyps (Übergang von krampf-artiger in spike-artige Aktivität, 31 % von 32 Gewebeschnitten). Auch bei Koapplikation mit einem Antikonvulsivum sind häufig Veränderungen des Aktivitätstyps zu sehen (38% von 76 Gewebeschnitten), eine Suppression der krampf-artigen Aktivität erfolgt nur selten (4%). Spike-artige Aktivität wird häufiger unterdrückt als krampf-artige Aktivität, durch Antikonvulsiva in 20% von 10 Gewebeschnitten (n.s.) und durch Koapplikation von AED und MDTI in 33% von 30 Gewebeschnitten (p < 0.001). Zwischen den Antikonvulsiva CBZ, VPA und PHT gibt es weder in der Phase ihrer alleinigen Applikation noch in der Phase ihrer Koapplikation mit VPM und PBN deutliche Unterschiede in der Wirkung. Bei der Auswertung aller Gewebeschnitte eines Patienten sind teilweise heterogene Effekte der AED und der Koapplikation von AED und MDTI zu beobachten (27% von 26 Patienten bei Gabe des AED, 42% von 31 Patienten bei Koapplikation von AED und MDTI). In unserem Modell zeigt sich unter Umgehung der Blut-Hirn-Schranke in den meisten Fällen eine Pharmakoresistenz gegenüber CBZ, VPA und PHT. Dies bestätigt die Annahme, dass im Parenchym lokalisierte Mechanismen eine wesentliche Rolle spielen. Die MDTI VPM und PBN verursachen Veränderungen des Musters der epileptiformen Aktivität. Dabei ist zu berücksichtigen, dass VPM Kalzium-Kanäle blockiert und neuroprotektiv wirken soll. Die Koapplikation eines Antikonvulsivums mit VPM und PBN führt zu einer „Verstärkung“ von Effekten der Antikonvulsiva, eine komplette Suppression kann jedoch nicht signifikant häufiger erreicht werden. Anhand der vorliegenden Ergebnisse ist anzunehmen, dass auch das resezierte Kortexgewebe von Patienten mit pharmakoresistenter Temporallappenepilepsie „Träger der Pharmako-resistenz“ ist. Die bei mehreren Patienten festgestellte Heterogenität der Behandlungseffekte in Gewebeschnitten eines Resektates stellt eine „homogene Verteilung Pharmakoresistenz-vermittelnder Mechanismen“ im chronisch epileptischen Kortexgewebe in Frage.Pharmacoresistance is a common phenomenon in treatment of focal epilepsies. Its mechanisms are poorly understood and a target of present investigations. The question arose, whether changes in target conformation of antiepileptic drugs (AED) may contribute to reduction in AED-efficacy (target-hypothesis). Another working-hypothesis is the reduction of AED-concentration at their place of action by ATP-dependent drug efflux pumps (MDT), located at the blood-brain-barrier and/or in the brain parenchyma (transporter-hypothesis). Previous studies showed that epileptiform activity can be induced in the dentate gyrus of resected hippocampal tissue. Pharmakoresistance to carbamazepine occurred in 80% of the tissue. In tissue from patients with only a short period of epilepsy due to tumor, epileptiform activity became suppressed. As the investigations were performed in a model of blood-brain- barrier-deprived tissue one could conclude that mechanisms located in the brain parenchyma may play a crucial role in pharmacoresistent epilepsy. Resection of the anterior temporal pole, performed in patients suffering from temporal lobe epilepsy offers the opportunity to perform in vitro studies of human cortical tissue. In the present study, we wanted to test i) whether stable epileptiform activity could be induced by ACSF with 8 mM [K+] and 50 µM Bicuculline, ii) whether the induced epileptiform activity is resistant to the antiepileptic drugs Carbamazepine (CBZ), Valproat (VPA) and Phenytoin (PHT), which are frequently used in antiepileptic monotherapy, iii) whether inhibition of the MDT Pgp and MRP by verapamil (VPM) and probenecid (PBN) affect the induced epileptiform activity and iv) whether co-application of one AED and both multidrug transport-inhibitors (MDTI) would reduce pharmacoresistance. By elevation of extracellular [K+] and application of 50 µM bicuculline periodic epileptiform activity has been induced in 85% of 166 slices. Two pattern of activity occurred, seizure-like activity (SLE, 121 slices) or spike-like activity (IIS, 20 slices), both transmitted by AMPA -/kainate-receptors. Without further drug application, the activity was stable for a minimum of 80 minutes. In 37 slices of patients with a clear cortical pathology spike-like-activity (IIS) was significantly more often observed (38%) than in 95 slices of patients with discreet cortical pathology (6%). Seizure-like activity was resistant to the AED CBZ, VPA or PHT in most of the slices (81% of 76 slices). MDTI alone modified the type of activity in some slices (transition of seizure-like activity to spike-like activity, 31% of 32 slices). Co-application of one AED with both MDTI also resulted in a modification of the activity type (38% of 76 slices) but a complete suppression of seizure-like events was very rarely achieved (4%). Spike-like- activity (IIS) became more often suppressed than seizure-like-activity by one AED (20% of 10 slices, n.s.) and by co-application of one AED and both MDTI (33% of 30 slices, p < 0.001) There was no difference between CBZ, VPA, and PHT with respect to their effects either when applied alone or together with MDTI. In some patients, two or more slices of the resected tissue showed heterogeneous results (26% of 26 patients for application of one AED, 42% of 31 patients for co-application of one AED and both MDTI). Our results obtained in a model of blood-brain-barrier-deprived human cortical tissue revealed pharmacoresistance of induced epileptiform activity to three major drugs (CBZ, VPA, PHT) in most of the slices. This approves the theory that resistance- mechanisms located in the brain parenchyma may play a crucial role. The MDTI verapamil and probenecid applied in the absence of AED changed the pattern of epileptiform activity from seizure-like to spike-like. Considering that blockade of calcium channels and neuroprotection by VPM are known or in discussion, additional experiments are necessary in order to explain the effect. Co-application of one AED with both MDTI clearly enhanced the effects of AED, but a complete suppression of induced epileptiform activity was not often reached. Regarding the latest discussion about substrate specificity of MDT, our results showed that there are no differences in substrate-specificy of Pgp and MRP for CBZ, VPA or PHT. Our results suggest, that the resected cortical tissue of patients with pharmacoresistant focal epilepsy „carries mechanisms of pharmacoresistance“, but the heterogeneity of results in slices of one patient question the homogeneous distribution of resistance-mechanisms in the resected tissue

Subarachnoid haemorrhage WFNS grade V: is maximal treatment worthwhile?

BACKGROUND: Aneurysmal subarachnoid haemorrhage (SAH) WFNS grade V is commonly known to be associated with high mortality and a very poor prognosis for survivors. Therefore, maximal invasive therapy is frequently delayed until any spontaneous improvement with or without an external ventricular drainage occurs. The aim of the study was to verify possible predictive factors and the probability of a favourable outcome in maximally treated patients. METHODS: One hundred and thirty-eight consecutive patients with WFNS grade V SAH were admitted between 03/2006 and 12/2010. Thirty-five patients died before aggressive therapy could proceed. One hundred and three patients received maximal treatment and were retrospectively evaluated. The outcome was assessed at discharge and in the follow-up with the Glasgow Outcome Scale. Univariate and multivariate linear regression models were performed to find predictors for an unfavourable outcome. RESULTS: Despite treatment, early mortality was 30 % (n = 31). At discharge, the rate of both vegetative and severely disabled patients was 27 % (n = 28). Favourable outcome at discharge was observed in 16 % (n = 16) of cases, whereas in the follow-up it rose to 26 % (n = 27). Multivariate full model regression identified intraventricular haematoma (IVH) and increasing age as independently predictive for poor outcome. CONCLUSIONS: Despite treatment, initial mortality and severe disability remain high. Nevertheless, a favourable outcome was achieved in 26 % of aggressively treated patients, rendering the withdrawal of maximal therapy for WFNS grade V SAH patients unacceptable today. In cases of old patients with IVH, the indication for aggressive therapy should be put in place more carefully due to a very poor prognosi

Supply-Demand Mismatch Transients in Susceptible Peri-infarct Hot Zones Explain the Origins of Spreading Injury Depolarizations

Peri-infarct depolarizations (PIDs) are seemingly spontaneous spreading depression-like waves that negatively impact tissue outcome in both experimental and human stroke. Factors triggering PIDs are unknown. Here, we show that somatosensory activation of peri-infarct cortex triggers PIDs when the activated cortex is within a critical range of ischemia. We show that the mechanism involves increased oxygen utilization within the activated cortex, worsening the supply-demand mismatch. We support the concept by clinical data showing that mismatch predisposes stroke patients to PIDs as well. Conversely, transient worsening of mismatch by episodic hypoxemia or hypotension also reproducibly triggers PIDs. Therefore, PIDs are triggered upon supply-demand mismatch transients in metastable peri-infarct hot zones due to increased demand or reduced supply. Based on the data, we propose that minimizing sensory stimulation and hypoxic or hypotensive transients in stroke and brain injury would reduce PID incidence and their adverse impact on outcome

Nimodipine Dose Reductions in the Treatment of Patients with Aneurysmal Subarachnoid Hemorrhage

BACKGROUND: The incidence of cerebral infarction and poor outcome in patients with aneurysmal subarachnoid hemorrhage (aSAH) is reduced by oral nimodipine but acute effects of the drug may include a significant decrease in mean arterial blood pressure (MAP). A dose reduction or discontinuation of the drug is recommended if recurrent MAP drops occur. The aim of our study was to evaluate the frequency and clinical significance of nimodipine dose modifications in patients suffering from aSAH. METHODS: 270 patients were included in our retrospective analysis of consecutively collected data of patients suffering from aSAH. The local treatment protocol was in accordance to national and international guidelines. Nimodipine was intended to be applied orally with a dosage of 60 mg every 4 h. RESULTS: Only 43.6 % of patients eligible for vasospasm prophylaxis with nimodipine received the full daily dose of 60 mg every 4 h. In 28.6 %, the dose had to be reduced by 50 % due to a significant reduction in blood pressure after administration and/or high dose of catecholamines. In 27.7 % of patients, oral administration of the drug was discontinued for the same reason. Dose reduction and discontinuation occurred with a significantly higher frequency in patients in poor clinical condition. Application of the full nimodipine dosage decreased the risk of unfavorable clinical outcome in multivariate analysis (OR 0.895, p = 0.029). CONCLUSIONS: Our results show that dose reduction or discontinuation of nimodipine due to changes in MAP occur frequently in clinical routine and may be associated with unfavorable clinical outcome

Associations of autozygosity with a broad range of human phenotypes

Abstract: In many species, the offspring of related parents suffer reduced reproductive success, a phenomenon known as inbreeding depression. In humans, the importance of this effect has remained unclear, partly because reproduction between close relatives is both rare and frequently associated with confounding social factors. Here, using genomic inbreeding coefficients (FROH) for >1.4 million individuals, we show that FROH is significantly associated (p < 0.0005) with apparently deleterious changes in 32 out of 100 traits analysed. These changes are associated with runs of homozygosity (ROH), but not with common variant homozygosity, suggesting that genetic variants associated with inbreeding depression are predominantly rare. The effect on fertility is striking: FROH equivalent to the offspring of first cousins is associated with a 55% decrease [95% CI 44–66%] in the odds of having children. Finally, the effects of FROH are confirmed within full-sibling pairs, where the variation in FROH is independent of all environmental confounding