Burden of disease among patients with prevalent Crohn's disease: results from a large German sickness fund.

PURPOSE: The aim of this study was to investigate the burden of disease among a real-world cohort of patients with prevalent Crohn's disease (CD) in Germany. METHODS: We conducted a retrospective cohort analysis using administrative claims data from the German AOK PLUS health insurance fund. Continuously insured patients with a CD diagnosis between 01 October 2014 and 31 December 2018 were selected and followed for at least 12 months or longer until death or end of data availability on 31 December 2019. Medication use (biologics, immunosuppressants (IMS), steroids, 5-aminosalicylic acid) was assessed sequentially in the follow-up period. Among patients with no IMS or biologics (advanced therapy), we investigated indicators of active disease and corticosteroid use. RESULTS: Overall, 9284 prevalent CD patients were identified. Within the study period, 14.7% of CD patients were treated with biologics and 11.6% received IMS. Approximately 47% of all prevalent CD patients had mild disease, defined as no advanced therapy and signs of disease activity. Of 6836 (73.6%) patients who did not receive advanced therapy in the follow-up period, 36.3% showed signs of active disease; 40.1% used corticosteroids (including oral budesonide), with 9.9% exhibiting steroid dependency (≥ 1 prescription every 3 months for at least 12 months) in the available follow-up. CONCLUSIONS: This study suggests that there remains a large burden of disease among patients who do not receive IMS or biologics in the real world in Germany. A revision of treatment algorithms of patients in this setting according to the latest guidelines may improve patient outcomes.

Real-world outcomes associated with switching to anti-TNFs versus other biologics in Crohn's Disease patients: A retrospective analysis using German claims data.

Background: The positioning of new biologic agents for the treatment of Crohn's disease (CD) following failure of initial anti-tumor necrosis factor (anti-TNF) therapy remains a challenge in the real world. Objectives: This study aims to investigate the real-world outcomes associated with the sequential use of biologics in CD patients that newly initiate anti-TNFs, specifically comparing those that switch to another anti-TNF versus biologics with other modes of action. Design: Retrospective cohort study. Methods: We identified CD patients who newly began anti-TNF therapy between 1 October 2014 and 31 December 2018 using two German claims databases. Patients were classified as within-class switchers (WCS) if they switched to another anti-TNF or outside-class switchers (OCS) if they switched to vedolizumab (VDZ) or ustekinumab (UST). To compare WCS and OCS, baseline covariates were adjusted through inverse probability of treatment weighting (IPTW), and time-to-event analyses were performed using Cox Proportional Hazard regressions. Results from both databases were meta-analyzed using an inverse variance model. Results: Overall, 376 prevalent adult CD patients who initiated anti-TNFs and switched to another biologic were identified. After IPTW, there were 152 and 177 patients in the WCS and OCS group, respectively. WCS were more likely to receive prolonged corticosteroid therapy [hazard ratio (HR): 1.63, 95% confidence interval (CI): 1.17-2.27, p = 0.004], switch a second time to a different biologic (HR: 2.44, 95% CI: 1.63-3.66, p < 0.001), and discontinue treatment (HR: 1.71, 95% CI: 1.25-2.34, p = 0.001) than OCS. Conclusion: This study suggests that CD patients exhibit more favorable outcomes when switching outside the anti-TNF class to VDZ or UST after initial anti-TNF failure than switching to a second anti-TNF. With loss of response to anti-TNFs as a concern in the real world, comparative evidence from claims data assessing sequential use of biologics can help optimize treatment algorithms of patients after anti-TNF failure.

Epidemiology of atrial fibrillation-related ischemic stroke and its association with DOAC uptake in Spain: first national population-based study 2005 to 2018.

INTRODUCTION AND OBJECTIVES: The incidence and prevalence of atrial fibrillation (AF), a major risk factor for stroke, has increased substantially in the past few years. However, several studies have reported a decline in AF-related stroke rates associated with higher uptake of direct oral anticoagulants (DOACs). This ecological study evaluated the association between DOAC uptake in Spain and the incidence rate (IR) of AF-related ischemic stroke. METHODS: Data were obtained from the Registry of Activity of Specialized Healthcare of the Spanish Ministry of Health (RAE-MDS). AF-related ischemic strokes were identified using International Classification of Diseases codes. IR were age-standardized and adjusted to the 2013 European standard population. Poisson regression models were used to identify the association between DOAC uptake and AF-related ischemic stroke in patients aged ≥ 65 years. RESULTS: Before the use of DOACs, the adjusted IR of AF-related ischemic stroke increased steadily from 2005 (IR=2.20 per 100 000 person/y) to 2012 (IR=2.67). Upon DOAC uptake in Spain from 2012 onwards for AF-related ischemic stroke prevention, the IR remained constant or decreased slightly (IR in 2018=2.66). Poisson regression showed that DOAC uptake was a significant predictor for the rate of AF-related ischemic stroke in patients older than 65 years (IRR=0.995; 95%CI, 0.995-0.996). CONCLUSIONS: This study shows an association between DOAC use and a reduced incidence of AF-related ischemic stroke. While this association is based on aggregate data and cannot demonstrate causality, these findings suggest that higher DOAC uptake could improve health outcomes in AF patients in Spain.

The habenular G-protein-coupled receptor 151 regulates synaptic plasticity and nicotine intake.

The habenula, an ancient small brain area in the epithalamus, densely expresses nicotinic acetylcholine receptors and is critical for nicotine intake and aversion. As such, identification of strategies to manipulate habenular activity may yield approaches to treat nicotine addiction. Here we show that GPR151, an orphan G-protein-coupled receptor (GPCR) highly enriched in the habenula of humans and rodents, is expressed at presynaptic membranes and synaptic vesicles and associates with synaptic components controlling vesicle release and ion transport. Deletion of Gpr151 inhibits evoked neurotransmission but enhances spontaneous miniature synaptic currents and eliminates short-term plasticity induced by nicotine. We find that GPR151 couples to the G-alpha inhibitory protein Gαo1 to reduce cyclic adenosine monophosphate (cAMP) levels in mice and in GPR151-expressing cell lines that are amenable to ligand screens. Gpr151- knockout (KO) mice show diminished behavioral responses to nicotine and self-administer greater quantities of the drug, phenotypes rescued by viral reexpression of Gpr151 in the habenula. These data identify GPR151 as a critical modulator of habenular function that controls nicotine addiction vulnerability.

Retrograde inhibition by a specific subset of interpeduncular α5 nicotinic neurons regulates nicotine preference.

Repeated exposure to drugs of abuse can produce adaptive changes that lead to the establishment of dependence. It has been shown that allelic variation in the α5 nicotinic acetylcholine receptor (nAChR) gene CHRNA5 is associated with higher risk of tobacco dependence. In the brain, α5-containing nAChRs are expressed at very high levels in the interpeduncular nucleus (IPN). Here we identified two nonoverlapping α5 + cell populations (α5- Amigo1 and α5- Epyc ) in mouse IPN that respond differentially to nicotine. Chronic nicotine treatment altered the translational profile of more than 1,000 genes in α5- Amigo1 neurons, including neuronal nitric oxide synthase (Nos1) and somatostatin (Sst). In contrast, expression of few genes was altered in the α5- Epyc population. We show that both nitric oxide and SST suppress optically evoked neurotransmitter release from the terminals of habenular (Hb) neurons in IPN. Moreover, in vivo silencing of neurotransmitter release from the α5- Amigo1 but not from the α5- Epyc population eliminates nicotine reward, measured using place preference. This loss of nicotine reward was mimicked by shRNA-mediated knockdown of Nos1 in the IPN. These findings reveal a proaddiction adaptive response to chronic nicotine in which nitric oxide and SST are released by a specific α5+ neuronal population to provide retrograde inhibition of the Hb-IPN circuit and thereby enhance the motivational properties of nicotine.

An essential role of acetylcholine-glutamate synergy at habenular synapses in nicotine dependence.

A great deal of interest has been focused recently on the habenula and its critical role in aversion, negative-reward and drug dependence. Using a conditional mouse model of the ACh-synthesizing enzyme choline acetyltransferase (Chat), we report that local elimination of acetylcholine (ACh) in medial habenula (MHb) neurons alters glutamate corelease and presynaptic facilitation. Electron microscopy and immuno-isolation analyses revealed colocalization of ACh and glutamate vesicular transporters in synaptic vesicles (SVs) in the central IPN. Glutamate reuptake in SVs prepared from the IPN was increased by ACh, indicating vesicular synergy. Mice lacking CHAT in habenular neurons were insensitive to nicotine-conditioned reward and withdrawal. These data demonstrate that ACh controls the quantal size and release frequency of glutamate at habenular synapses, and suggest that the synergistic functions of ACh and glutamate may be generally important for modulation of cholinergic circuit function and behavior.

Suppression of Peripheral Pain by Blockade of Voltage-Gated Calcium 2.2 Channels in Nociceptors Induces RANKL and Impairs Recovery From Inflammatory Arthritis in a Mouse Model.

OBJECTIVE: A hallmark of rheumatoid arthritis (RA) is the chronic pain that accompanies inflammation and joint deformation. Patients with RA rate pain relief as the highest priority; however, few studies have addressed the efficacy and safety of therapies directed specifically toward pain pathways. The ω-conotoxin MVIIA (ziconotide) is used in humans to alleviate persistent pain syndromes, because it specifically blocks the voltage-gated calcium 2.2 (CaV 2.2) channel, which mediates the release of neurotransmitters and proinflammatory mediators from peripheral nociceptor nerve terminals. The aims of this study were to investigate whether blockade of CaV 2.2 can suppress arthritis pain, and to examine the progression of induced arthritis during persistent CaV 2.2 blockade. METHODS: Transgenic mice expressing a membrane-tethered form of MVIIA under the control of a nociceptor-specific gene (MVIIA-transgenic mice) were used in the experiments. The mice were subjected to unilateral induction of joint inflammation using a combination of antigen and collagen. RESULTS: CaV 2.2 blockade mediated by tethered MVIIA effectively suppressed arthritis-induced pain; however, in contrast to their wild-type littermates, which ultimately regained use of their injured joint as inflammation subsided, MVIIA-transgenic mice showed continued inflammation, with up-regulation of the osteoclast activator RANKL and concomitant joint and bone destruction. CONCLUSION: Taken together, our results indicate that alleviation of peripheral pain by blockade of CaV 2.2- mediated calcium influx and signaling in nociceptor sensory neurons impairs recovery from induced arthritis and point to the potentially devastating effects of using CaV 2.2 channel blockers as analgesics during inflammation.

Conserved expression of the GPR151 receptor in habenular axonal projections of vertebrates.

The habenula is a phylogenetically conserved brain structure in the epithalamus. It is a major node in the information flow between fronto-limbic brain regions and monoaminergic brainstem nuclei, and is thus anatomically and functionally ideally positioned to regulate emotional, motivational, and cognitive behaviors. Consequently, the habenula may be critically important in the pathophysiology of psychiatric disorders such as addiction and depression. Here we investigated the expression pattern of GPR151, a G protein-coupled receptor (GPCR), whose mRNA has been identified as highly and specifically enriched in habenular neurons by in situ hybridization and translating ribosome affinity purification (TRAP). In the present immunohistochemical study we demonstrate a pronounced and highly specific expression of the GPR151 protein in the medial and lateral habenula of rodent brain. Specific expression was also seen in efferent habenular fibers projecting to the interpeduncular nucleus, the rostromedial tegmental area, the rhabdoid nucleus, the mesencephalic raphe nuclei, and the dorsal tegmental nucleus. Using confocal microscopy and quantitative colocalization analysis, we found that GPR151-expressing axons and terminals overlap with cholinergic, substance P-ergic, and glutamatergic markers. Virtually identical expression patterns were observed in rat, mouse, and zebrafish brains. Our data demonstrate that GPR151 is highly conserved, specific for a subdivision of the habenular neurocircuitry, and constitutes a promising novel target for psychiatric drug development.

The habenulo-interpeduncular pathway in nicotine aversion and withdrawal.

Progress has been made over the last decade in our understanding of the brain areas and circuits involved in nicotine reward and withdrawal, leading to models of addiction that assign different addictive behaviors to distinct, yet overlapping, neural circuits (Koob and Volkow, 2010; Lobo and Nestler, 2011; Tuesta et al., 2011; Volkow et al., 2011). Recently the habenulo-interpeduncular (Hb-IPN) midbrain pathway has re-emerged as a new critical crossroad that influences the brain response to nicotine. This brain area is particularly enriched in nicotinic acetylcholine receptor (nAChR) subunits α5, α3 and ß4 encoded by the CHRNA5-A3-B4 gene cluster, which has been associated with vulnerability to tobacco dependence in human genetics studies. This finding, together with studies in mice involving deletion and replacement of nAChR subunits, and investigations of the circuitry, cell types and electrophysiological properties, have begun to identify the molecular mechanisms that take place in the MHb-IPN which underlie critical aspects of nicotine dependence. In the current review we describe the anatomical and functional connections of the MHb-IPN system, as well as the contribution of specific nAChRs subtypes in nicotine-mediated behaviors. Finally, we discuss the specific electrophysiological properties of MHb-IPN neuronal populations and how nicotine exposure alters their cellular physiology, highlighting the unique role of the MHb-IPN in the context of nicotine aversion and withdrawal. This article is part of the Special Issue entitled 'The Nicotinic Acetylcholine Receptor: From Molecular Biology to Cognition'.

Gene-specific methylation control of H3K9 and H3K36 on neurotrophic BDNF versus astroglial GFAP genes by KDM4A/C regulates neural stem cell differentiation.

Neural stem cell (NSC) state and fate depend on spatially and temporally synchronized transcriptional and epigenetic regulation of the expression of extrinsic signaling factors and intrinsic cell-specific genes, but the functional roles for chromatin-modifying enzymes in neural differentiation remain poorly understood. Here we show that the histone demethylases KDM4A (JMJD2A) and KDM4C (JMJD2C) are essential for proper differentiation of NSCs in vitro and in vivo. KDM4A/C were required for neuronal differentiation, survival and expression of the neurotrophic signaling factor BDNF in association with promoter H3K9 demethylation and RNA polymerase II recruitment. Unexpectedly, KDM4A/C were essential for selective H3K36 demethylation and loss of RNA polymerase II recruitment in transcribed regions of the astrocyte-characteristic gene GFAP, thereby in parallel repressing astrocytic differentiation by control of elongation. We propose that gene- and lysine-specific KDM4A/C-mediated control of histone methylation and thereby regulation of intrinsic factors and signaling factors such as BDNF provide a novel control mechanism of lineage decision.

Habenular expression of rare missense variants of the ß4 nicotinic receptor subunit alters nicotine consumption.

The CHRNA5-CHRNA3-CHRNB4 gene cluster, encoding the α5, α3, and ß4 nicotinic acetylcholine receptor (nAChR) subunits, has been linked to nicotine dependence. The habenulo-interpeduncular (Hb-IPN) tract is particularly enriched in α3ß4 nAChRs. We recently showed that modulation of these receptors in the medial habenula (MHb) in mice altered nicotine consumption. Given that ß4 is rate-limiting for receptor activity and that single nucleotide polymorphisms (SNPs) in CHRNB4 have been linked to altered risk of nicotine dependence in humans, we were interested in determining the contribution of allelic variants of ß4 to nicotine receptor activity in the MHb. We screened for missense SNPs that had allele frequencies >0.0005 and introduced the corresponding substitutions in Chrnb4. Fourteen variants were analyzed by co-expression with α3. We found that ß4A90I and ß4T374I variants, previously shown to associate with reduced risk of smoking, and an additional variant ß4D447Y, significantly increased nicotine-evoked current amplitudes, while ß4R348C, the mutation most frequently encountered in sporadic amyotrophic lateral sclerosis (sALS), showed reduced nicotine currents. We employed lentiviruses to express ß4 or ß4 variants in the MHb. Immunoprecipitation studies confirmed that ß4 lentiviral-mediated expression leads to specific upregulation of α3ß4 but not ß2 nAChRs in the Mhb. Mice injected with the ß4-containing virus showed pronounced aversion to nicotine as previously observed in transgenic Tabac mice overexpressing Chrnb4 at endogenous sites including the MHb. Habenular expression of the ß4 gain-of-function allele T374I also resulted in strong aversion, while transduction with the ß4 loss-of function allele R348C failed to induce nicotine aversion. Altogether, these data confirm the critical role of habenular ß4 in nicotine consumption, and identify specific SNPs in CHRNB4 that modify nicotine-elicited currents and alter nicotine consumption in mice.

Reexposure to nicotine during withdrawal increases the pacemaking activity of cholinergic habenular neurons.

The discovery of genetic variants in the cholinergic receptor nicotinic CHRNA5-CHRNA3-CHRNB4 gene cluster associated with heavy smoking and higher relapse risk has led to the identification of the midbrain habenula-interpeduncular axis as a critical relay circuit in the control of nicotine dependence. Although clear roles for α3, ß4, and α5 receptors in nicotine aversion and withdrawal have been established, the cellular and molecular mechanisms that participate in signaling nicotine use and contribute to relapse have not been identified. Here, using translating ribosome affinity purification (TRAP) profiling, electrophysiology, and behavior, we demonstrate that cholinergic neurons, but not peptidergic neurons, of the medial habenula (MHb) display spontaneous tonic firing of 2-10 Hz generated by hyperpolarization-activated cyclic nucleotide-gated (HCN) pacemaker channels and that infusion of the HCN pacemaker antagonist ZD7288 in the habenula precipitates somatic and affective signs of withdrawal. Further, we show that a strong, α3ß4-dependent increase in firing frequency is observed in these pacemaker neurons upon acute exposure to nicotine. No change in the basal or nicotine-induced firing was observed in cholinergic MHb neurons from mice chronically treated with nicotine. We observe, however, that, during withdrawal, reexposure to nicotine doubles the frequency of pacemaking activity in these neurons. These findings demonstrate that the pacemaking mechanism of cholinergic MHb neurons controls withdrawal, suggesting that the heightened nicotine sensitivity of these neurons during withdrawal may contribute to smoking relapse.

Aversion to nicotine is regulated by the balanced activity of ß4 and α5 nicotinic receptor subunits in the medial habenula.

Nicotine dependence is linked to single nucleotide polymorphisms in the CHRNB4-CHRNA3-CHRNA5 gene cluster encoding the α3ß4α5 nicotinic acetylcholine receptor (nAChR). Here we show that the ß4 subunit is rate limiting for receptor activity, and that current increase by ß4 is maximally competed by one of the most frequent variants associated with tobacco usage (D398N in α5). We identify a ß4-specific residue (S435), mapping to the intracellular vestibule of the α3ß4α5 receptor in close proximity to α5 D398N, that is essential for its ability to increase currents. Transgenic mice with targeted overexpression of Chrnb4 to endogenous sites display a strong aversion to nicotine that can be reversed by viral-mediated expression of the α5 D398N variant in the medial habenula (MHb). Thus, this study both provides insights into α3ß4α5 receptor-mediated mechanisms contributing to nicotine consumption, and identifies the MHb as a critical element in the circuitry controlling nicotine-dependent phenotypes.

DISC1, PDE4B, and NDE1 at the centrosome and synapse.

Disrupted-In-Schizophrenia 1 (DISC1) is a risk factor for schizophrenia and other major mental illnesses. Its protein binding partners include the Nuclear Distribution Factor E Homologs (NDE1 and NDEL1), LIS1, and phosphodiesterases 4B and 4D (PDE4B and PDE4D). We demonstrate that NDE1, NDEL1 and LIS1, together with their binding partner dynein, associate with DISC1, PDE4B and PDE4D within the cell, and provide evidence that this complex is present at the centrosome. LIS1 and NDEL1 have been previously suggested to be synaptic, and we now demonstrate localisation of DISC1, NDE1, and PDE4B at synapses in cultured neurons. NDE1 is phosphorylated by cAMP-dependant Protein Kinase A (PKA), whose activity is, in turn, regulated by the cAMP hydrolysis activity of phosphodiesterases, including PDE4. We propose that DISC1 acts as an assembly scaffold for all of these proteins and that the NDE1/NDEL1/LIS1/dynein complex is modulated by cAMP levels via PKA and PDE4.