Distinctive In Vitro Phenotypes in iPSC-Derived Neurons From Patients With Gain- and Loss-of-Function SCN2A Developmental and Epileptic Encephalopathy.

SCN2A encodes NaV1.2, an excitatory neuron voltage-gated sodium channel and a major monogenic cause of neurodevelopmental disorders, including developmental and epileptic encephalopathies (DEE) and autism. Clinical presentation and pharmocosensitivity vary with the nature of SCN2A variant dysfunction and can be divided into gain-of-function (GoF) cases with pre- or peri-natal seizures and loss-of-function (LoF) patients typically having infantile spasms after 6 months of age. We established and assessed patient induced pluripotent stem cell (iPSC) - derived neuronal models for two recurrent SCN2A DEE variants with GoF R1882Q and LoF R853Q associated with early- and late-onset DEE, respectively. Two male patient-derived iPSC isogenic pairs were differentiated using Neurogenin-2 overexpression yielding populations of cortical-like glutamatergic neurons. Functional properties were assessed using patch clamp and multielectrode array recordings and transcriptomic profiles obtained with total mRNA sequencing after 2-4 weeks in culture. At 3 weeks of differentiation, increased neuronal activity at cellular and network levels was observed for R1882Q iPSC-derived neurons. In contrast, R853Q neurons showed only subtle changes in excitability after 4 weeks and an overall reduced network activity after 7 weeks in vitro. Consistent with the reported efficacy in some GoF SCN2A patients, phenytoin (sodium channel blocker) reduced the excitability of neurons to the control levels in R1882Q neuronal cultures. Transcriptomic alterations in neurons were detected for each variant and convergent pathways suggested potential shared mechanisms underlying SCN2A DEE. In summary, patient iPSC-derived neuronal models of SCN2A GoF and LoF pathogenic variants causing DEE show specific functional and transcriptomic in vitro phenotypes.

Carbogen-Induced Respiratory Acidosis Blocks Experimental Seizures by a Direct and Specific Inhibition of NaV1.2 Channels in the Axon Initial Segment of Pyramidal Neurons.

Brain pH is a critical factor for determining neuronal activity, with alkalosis increasing and acidosis reducing excitability. Acid shifts in brain pH through the breathing of carbogen (5% CO2/95% O2) reduces seizure susceptibility in animal models and patients. The molecular mechanisms underlying this seizure protection remain to be fully elucidated. Here, we demonstrate that male and female mice exposed to carbogen are fully protected from thermogenic-triggered seizures. Whole-cell patch-clamp recordings revealed that acid shifts in extracellular pH (pHo) significantly reduce action potential firing in CA1 pyramidal neurons but did not alter firing in hippocampal inhibitory interneurons. In real-time dynamic clamp experiments, acidification reduced simulated action potential firing generated in hybrid model neurons expressing the excitatory neuron predominant NaV1.2 channel. Conversely, acidification had no effect on action potential firing in hybrid model neurons expressing the interneuron predominant NaV1.1 channel. Furthermore, knockdown of Scn2a mRNA in vivo using antisense oligonucleotides reduced the protective effects of carbogen on seizure susceptibility. Both carbogen-mediated seizure protection and the reduction in CA1 pyramidal neuron action potential firing by low pHo were maintained in an Asic1a knock-out mouse ruling out this acid-sensing channel as the underlying molecular target. These data indicate that the acid-mediated reduction in excitatory neuron firing is mediated, at least in part, through the inhibition of NaV1.2 channels, whereas inhibitory neuron firing is unaffected. This reduction in pyramidal neuron excitability is the likely basis of seizure suppression caused by carbogen-mediated acidification.SIGNIFICANCE STATEMENT Brain pH has long been known to modulate neuronal excitability. Here, we confirm that brain acidification reduces seizure susceptibility in a mouse model of thermogenic seizures. Extracellular acidification reduced excitatory pyramidal neuron firing while having no effect on interneuron firing. Acidification also reduced dynamic clamp firing in cells expressing the NaV1.2 channel but not in cells expressing NaV1.1 channels. In vivo knockdown of Scn2a mRNA reduced seizure protection of acidification. In contrast, acid-mediated seizure protection was maintained in the Asic1a knock-out mouse. These data suggest NaV1.2 channel as an important target for acid-mediated seizure protection. Our results have implications on how natural variations in pH can modulate neuronal excitability and highlight potential antiseizure drug development strategies based on the NaV1.2 channel.

Retinal Dysfunction in a Mouse Model of HCN1 Genetic Epilepsy.

Pathogenic variants in HCN1 are associated with a range of epilepsy syndromes including a developmental and epileptic encephalopathy. The recurrent de novo HCN1 pathogenic variant (M305L) results in a cation leak, allowing the flux of excitatory ions at potentials where the wild-type channels are closed. The Hcn1M294L mouse recapitulates patient seizure and behavioral phenotypes. As HCN1 channels are highly expressed in rod and cone photoreceptor inner segments, where they shape the light response, mutated channels are likely to impact visual function. Electroretinogram (ERG) recordings from male and female mice Hcn1M294L mice revealed a significant decrease in the photoreceptor sensitivity to light, as well as attenuated bipolar cell (P2) and retinal ganglion cell responses. Hcn1M294L mice also showed attenuated ERG responses to flickering lights. ERG abnormalities are consistent with the response recorded from a single female human subject. There was no impact of the variant on the structure or expression of the Hcn1 protein in the retina. In silico modeling of photoreceptors revealed that the mutated HCN1 channel dramatically reduced light-induced hyperpolarization, resulting in more Ca2+ flux during the response when compared with the wild-type situation. We propose that the light-induced change in glutamate release from photoreceptors during a stimulus will be diminished, significantly blunting the dynamic range of this response. Our data highlight the importance of HCN1 channels to retinal function and suggest that patients with HCN1 pathogenic variants are likely to have a dramatically reduced sensitivity to light and a limited ability to process temporal information.SIGNIFICANCE STATEMENT Pathogenic variants in HCN1 are emerging as an important cause of catastrophic epilepsy. HCN1 channels are ubiquitously expressed throughout the body, including the retina. Electroretinogram recordings from a mouse model of HCN1 genetic epilepsy showed a marked decrease in the photoreceptor sensitivity to light and a reduced ability to respond to high rates of light flicker. No morphologic deficits were noted. Simulation data suggest that the mutated HCN1 channel blunts light-induced hyperpolarization and consequently limits the dynamic range of this response. Our results provide insights into the role HCN1 channels play in retinal function as well as highlighting the need to consider retinal dysfunction in disease caused by HCN1 variants. The characteristic changes in the electroretinogram open the possibility of using this tool as a biomarker for this HCN1 epilepsy variant and to facilitate development of treatments.

Improved Cardiac Function in Postischemic Rats Using an Optimized Cardiac Reprogramming Cocktail Delivered in a Single Novel Adeno-Associated Virus.

BACKGROUND: Cardiac reprogramming is a technique to directly convert nonmyocytes into myocardial cells using genes or small molecules. This intervention provides functional benefit to the rodent heart when delivered at the time of myocardial infarction or activated transgenically up to 4 weeks after myocardial infarction. Yet, several hurdles have prevented the advancement of cardiac reprogramming for clinical use. METHODS: Through a combination of screening and rational design, we identified a cardiac reprogramming cocktail that can be encoded in a single adeno-associated virus. We also created a novel adeno-associated virus capsid that can transduce cardiac fibroblasts more efficiently than available parental serotypes by mutating posttranslationally modified capsid residues. Because a constitutive promoter was needed to drive high expression of these cell fate-altering reprogramming factors, we included binding sites to a cardiomyocyte-restricted microRNA within the 3' untranslated region of the expression cassette that limits expression to nonmyocytes. After optimizing this expression cassette to reprogram human cardiac fibroblasts into induced cardiomyocyte-like cells in vitro, we also tested the ability of this capsid/cassette combination to confer functional benefit in acute mouse myocardial infarction and chronic rat myocardial infarction models. RESULTS: We demonstrated sustained, dose-dependent improvement in cardiac function when treating a rat model 2 weeks after myocardial infarction, showing that cardiac reprogramming, when delivered in a single, clinically relevant adeno-associated virus vector, can support functional improvement in the postremodeled heart. This benefit was not observed with GFP (green fluorescent protein) or a hepatocyte reprogramming cocktail and was achieved even in the presence of immunosuppression, supporting myocyte formation as the underlying mechanism. CONCLUSIONS: Collectively, these results advance the application of cardiac reprogramming gene therapy as a viable therapeutic approach to treat chronic heart failure resulting from ischemic injury.

Preface: Special issue: "Ion channels and genetic epilepsy".

This preface introduces the Journal of Neurochemistry Special Issue on Advances in Epilepsy Research. Epilepsy is a devastating disease characterized by recurrent seizures. Despite the addition of numerous therapeutics over the last few decades epilepsy patients resistant to standard of care treatments remains stubbornly high. This highlights a clear unmet clinical need and the importance of new research into this disease. One major advance over the last two decades has been the recognition that genetic factors play a significant role in the underlying pathogenesis of epilepsy. Much of our insights into the pathogenic mechanisms underlying genetic epilepsy has come from research into genes that encode ion channels. In this issue, there are up-to-date reviews discussing epilepsy caused by variation in HCN channels, voltage-dependent sodium channels, voltage-dependent calcium channels, and GABAA receptors. The reviews highlight our understanding of the genotype-phenotype relationships and the identification of precision medicine approaches. Complimenting this is a review on metabolic aspects modulating ion channels in genetic disease. This issue also has fundamental research manuscripts investigating how currently approved drugs may rescue NMDA receptor dysfunction and how in vitro neuron cultures can be used to probe network scale deficits and drug impacts in SCN2A disease. Other primary data manuscripts include those focusing on metabolic therapies, gut microbiota, and new in vivo screening tools for identifying novel anti-seizure drugs. Collectively, manuscripts published as part of this edition highlight recent research gains, especially in our understanding of genetic causes of epilepsy involving ion channels.

Variant-specific in vitro neuronal network phenotypes and drug sensitivity in SCN2A developmental and epileptic encephalopathy.

De novo variants in the NaV1.2 voltage-gated sodium channel gene SCN2A are among the major causes of developmental and epileptic encephalopathies (DEE). Based on their biophysical impact on channel conductance and gating, SCN2A DEE variants can be classified into gain-of-function (GoF) or loss-of-function (LoF). Clinical and functional data have linked early seizure onset DEE to the GoF SCN2A variants, whereas late seizure onset DEE is associated with the loss of SCN2A function. This study aims to assess the impact of GoF and LoF SCN2A variants on cultured neuronal network activity and explore their modulation by selected antiseizure medications (ASM). To this end, primary cortical cultures were generated from two knock-in mouse lines carrying variants corresponding to human GoF SCN2A p.R1882Q and LoF p.R853Q DEE variant. In vitro neuronal network activity and responses to ASM were analyzed using multielectrode array (MEA) between 2 and 4 weeks in culture. The SCN2A p.R1882Q neuronal cultures showed significantly greater mean firing and burst firing. Their network synchronicity was also higher. In contrast, the SCN2A p.R853Q cultures showed lower mean firing rate, and burst firing events were less frequent. The network synchronicity was also lower. Phenytoin and levetiracetam reduced the excitability of GoF cultures, while retigabine showed differential and potentially beneficial effects on cultures with both GoF and LoF variants. We conclude that in vitro neuronal networks harboring SCN2A GoF or LoF DEE variants present with distinctive phenotypes and responses to ASM.

Transcriptional network analysis of peripheral blood leukocyte subsets in multiple sclerosis identifies a pathogenic role for a cytotoxicity-associated gene network in myeloid cells.

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system affecting predominantly adults. It is a complex disease associated with both environmental and genetic risk factors. Although over 230 risk single-nucleotide polymorphisms have been associated with MS, all are common human variants. The mechanisms by which they increase the risk of MS, however, remain elusive. We hypothesized that a complex genetic phenotype such as MS could be driven by coordinated expression of genes controlled by transcriptional regulatory networks. We, therefore, constructed a gene coexpression network from microarray expression analyses of five purified peripheral blood leukocyte subsets of 76 patients with relapsing remitting MS and 104 healthy controls. These analyses identified a major network (or module) of expressed genes associated with MS that play key roles in cell-mediated cytotoxicity which was downregulated in monocytes of patients with MS. Manipulation of the module gene expression was achieved in vitro through small interfering RNA gene knockdown of identified drivers. In a mouse model, network gene knockdown modulated the autoimmune inflammatory MS model disease-experimental autoimmune encephalomyelitis. This research implicates a cytotoxicity-associated gene network in myeloid cells in the pathogenesis of MS.

Stuttering associated with a pathogenic variant in the chaperone protein cyclophilin 40.

Stuttering is a common speech disorder that interrupts speech fluency and tends to cluster in families. Typically, stuttering is characterized by speech sounds, words or syllables which may be repeated or prolonged and speech that may be further interrupted by hesitations or 'blocks'. Rare variants in a small number of genes encoding lysosomal pathway proteins have been linked to stuttering. We studied a large four-generation family in which persistent stuttering was inherited in an autosomal dominant manner with disruption of the cortico-basal-ganglia-thalamo-cortical network found on imaging. Exome sequencing of three affected family members revealed the PPID c.808C>T (p.Pro270Ser) variant that segregated with stuttering in the family. We generated a Ppid p.Pro270Ser knock-in mouse model and performed ex vivo imaging to assess for brain changes. Diffusion-weighted MRI in the mouse revealed significant microstructural changes in the left corticospinal tract, as previously implicated in stuttering. Quantitative susceptibility mapping also detected changes in cortico-striatal-thalamo-cortical loop tissue composition, consistent with findings in affected family members. This is the first report to implicate a chaperone protein in the pathogenesis of stuttering. The humanized Ppid murine model recapitulates network findings observed in affected family members.

Multimorbidity impacts cardiovascular disease risk following percutaneous coronary intervention: latent class analysis of the Melbourne Interventional Group (MIG) registry.

BACKGROUND: Multimorbidity is strongly associated with disability or functional decline, poor quality of life and high consumption of health care services. This study aimed (1) To identify patterns of multimorbidity among patients undergoing first recorded percutaneous coronary intervention (PCI); (2) To explore the association between the identified patterns of multimorbidity on length of hospital stay, 30-day and 12- month risk of major adverse cardiac and cerebrovascular events (MACCE) after PCI. METHODS: A retrospective cohort study of the Melbourne Interventional Group (MIG) registry. This study included 14,025 participants who underwent their first PCI from 2005 to 2015 in Victoria, Australia. Based on a probabilistic modelling approach, Latent class analysis was adopted to classify clusters of people who shared similar combinations and magnitude of the comorbidity of interest. Logistic regression models were used to estimate odd ratios and 95% confidence interval (CI) for the 30-day and 12-month MACCE. RESULTS: More than two-thirds of patients had multimorbidity, with the most prevalent conditions being hypertension (59%) and dyslipidaemia (60%). Four distinctive multimorbidity clusters were identified each with significant associations for higher risk of 30-day and 12-month MACCE. The cluster B had the highest risk of 30-day MACCE event that was characterised by a high prevalence of reduced estimated glomerular filtration rate (92%), hypertension (73%) and reduced ejection fraction (EF) (57%). The cluster C, characterised by a high prevalence of hypertension (94%), dyslipidaemia (88%), reduced eGFR (87%), diabetes (73%) and reduced EF (65%) had the highest risk of 12-month MACCE and highest length of hospital stay. CONCLUSION: Hypertension and dyslipidaemia are prevalent in at least four in ten patients undergoing coronary angioplasty. This study showed that clusters of patients with multimorbidity had significantly different risk of 30-day and 12-month MACCE after PCI. This suggests the necessity for treatment approaches that are more personalised and customised to enhance patient outcomes and the quality of care delivered to patients in various comorbidity clusters. These results should be validated in a prospective cohort and to evaluate the potential impacts of these clusters on the prevention of MACCE after PCI.

Cardiovascular Disease Risk Scores and Incident Dementia and Cognitive Decline in Older Men and Women.

INTRODUCTION: Risk factors for cardiovascular disease (CVD) also increase the risk of dementia. However, whether commonly used CVD risk scores are associated with dementia risk in older adults who do not have a history of CVD, and potential gender differences in this association, remains unclear. The aim of this study was to determine whether CVD risk scores are prospectively associated with cognitive decline and dementia in initially healthy older men and women. METHODS: A total of19,114 participants from a prospective cohort of individuals aged 65+ years without known CVD or dementia were recruited. The atherosclerotic cardiovascular disease risk score (ASCVDRS), Systematic Coronary Risk Evaluation 2-Older Persons (SCORE2-OP), and the Framingham risk score (FRS) were calculated at baseline. Risk of dementia (according to DSM-IV criteria) and cognitive decline (defined as a >1.5 standard deviation decline in global cognition, episodic memory, psychomotor speed, or verbal fluency from the previous year) were assessed using hazard ratio. RESULTS: Over a median follow-up of 6.4 years, 850 individuals developed dementia and 4,352 cognitive decline. Men and women in the highest ASCVDRS tertile had a 41% (95% CI 1.08, 1.85) and 45% (1.11, 1.89) increased risk of dementia compared to the lowest tertile, respectively. Likewise, men and women in the highest SCORE2-OP tertile had a 64% (1.24, 2.16) and 60% (1.22, 2.11) increased risk of dementia compared to the lowest tertile, respectively. Findings were similar, but the risk was slightly lesser when examining risk of cognitive decline for both ASCVDRS and SCORE2-OP. However, FRS was only associated with the risk of cognitive decline among women (highest vs. lowest tertiles: 1.13 [1.01-1.26]). CONCLUSION: These findings suggest the utility of the ASCVDRS and SCORE2-OP in clinical practice, to not only assess future risk of CVD, but also as potential early indicators of cognitive impairment, even in relatively healthy older men and women.

Development and Validation of Scores to Predict Prolonged Mechanical Ventilation after Cardiac Surgery.

OBJECTIVES: To optimize the early prediction of prolonged postoperative mechanical ventilation after cardiac surgery (>24 hours postoperatively). DESIGN: The authors performed a retrospective analysis. SETTING: The Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) database was utilized. PARTICIPANTS: All patients included in the ANZSCTS database between January 2015 and December 2018 were analyzed. INTERVENTIONS: No interventions were performed in this observational study. MEASUREMENTS AND MAIN RESULTS: A previously developed model was modified to allow retrospective risk calculation and model assessment (Modified Hessels score). The database was split into development and validation sets. A new risk model was developed using forward and backward stepwise elimination (ANZ-PreVent score). The authors assessed 48,382 patients, of whom 5004 (10.3%) were ventilated mechanically for >24 hours post-operatively. The Modified Hessels score demonstrated good performance in this database, with a c-index of 0.78 (95% CI 0.77-0.78) and a Brier score of 0.08. The newly developed ANZ-PreVent score demonstrated better performance (validation cohort, n = 12,229), with a c-index of 0.84 (95% CI 0.83-0.85) (p < 0.0001) and a Brier score of 0.07. Both scores performed better than the severity of illness scores commonly used to predict outcomes in intensive care. CONCLUSIONS: The authors validated a modified version of an existing prediction score and developed the ANZ-PreVent score, with improved performance for identifying patients at risk of ventilation for >24 hours. The improved score can be used to identify high-risk patients for targeted interventions in future randomized controlled trials.

Comparison of Characteristics and Outcomes in Patients With Acute Decompensated Heart Failure Admitted Under General Medicine and Cardiology Units.

BACKGROUND: Acute decompensated heart failure (ADHF) is a leading cause of cardiovascular disease hospitalisations associated with significant morbidity and mortality. In hospitals, HF patients are typically managed by cardiology or physician teams, with differences in patient demographics and clinical outcomes. This study utilises contemporary HF registry data to compare patient characteristics and outcomes in those with ADHF admitted into General Medicine and Cardiology units. METHODS: The Victorian Cardiac Outcomes Registry was utilised to identify patients hospitalised with ADHF 30-day period in each of four consecutive years. We compared patient characteristics, pharmacological management and outpatient follow-up of patients admitted to General Medicine and Cardiology units. Primary outcome measures included in-hospital mortality, 30-day readmission, and 30-day mortality. RESULTS: Between 2014 and 2017, a total of 1,253 patients with ADHF admissions were registered, with 53% admitted in General Medicine units and 47% in Cardiology units. General Medicine patients were more likely to be older (82 vs 71 years; p<0.001), female (51% vs 34%; p<0.001), and have higher prevalence of comorbidities and preserved left ventricular function (p<0.001). There were no differences in primary outcome measures between General Medicine and Cardiology in terms of: in-hospital mortality (5.0% vs 3.9%; p=0.35), 30-day readmission (23.4% vs 23.6%; p=0.93), and 30-day mortality (10.0% vs 8.0%; p=0.21). CONCLUSIONS: Hospitalised patients with HF continue to have high mortality and rehospitalisation rates. The choice of treatment by General Medicine or Cardiology units, based on the particular medical profile and individual needs of the patients, provides equivalent outcomes.

Prevalence and Predictors of Emergency Medical Service Use in Patients Undergoing Primary Percutaneous Coronary Intervention for ST-Elevation Myocardial Infarction.

AIM: We aim to describe prevalence of Emergency Medical Service (EMS) use, investigate factors predictive of EMS use, and determine if EMS use predicts treatment delay and mortality in our ST-elevation myocardial infarction (STEMI) cohort. METHOD: We prospectively collected data on 5,602 patients presenting with STEMI for primary percutaneous coronary intervention (PCI) transported to PCI-capable hospitals in Victoria, Australia, from 2013-2018 who were entered into the Victorian Cardiac Outcomes Registry (VCOR). We linked this dataset to the Ambulance Victoria and National Death Index (NDI) datasets. We excluded late presentation, thrombolysed, and in-hospital STEMI, as well as patients presenting with cardiogenic shock and out-of-hospital cardiac arrest. RESULTS: In total, 74% of patients undergoing primary PCI for STEMI used EMS. Older age, female gender, higher socioeconomic status, and a history of prior ischaemic heart disease were independent predictors of using EMS. EMS use was associated with shorter adjusted door-to-balloon (53 vs 72 minutes, p<0.001) and symptom-to-balloon (183 vs 212 minutes, p<0.001) times. Mode of transport was not predictive of 30-day or 12-month mortality. CONCLUSIONS: EMS use in Victoria is relatively high compared with internationally reported data. EMS use reduces treatment delay. Predictors of EMS use in our cohort are consistent with those prevalent in prior literature. Understanding the patients who are less likely to use EMS might inform more targeted education campaigns in the future.

Clinical Outcomes of Renal Transplant Recipients Undergoing Percutaneous Coronary Intervention.

BACKGROUND: Clinical outcomes of patients with renal transplant (RT) undergoing percutaneous coronary intervention (PCI) remain poorly elucidated. METHOD: Between 2014 and 2021, data were analysed for the following three groups of patients undergoing PCI enrolled in a multicentre Australian registry: (1) RT recipients (n=226), (2) patients on dialysis (n=992), and (3) chronic kidney disease (CKD) patients (estimated glomerular filtration rate [eGFR], 30‒60 mL/min per 1.73 m2) without previous RT (n=15,534). Primary outcome was 30-day major adverse cardiac and cerebrovascular events (MACCEs)-composite of mortality, myocardial infarction, stent thrombosis, target vessel revascularisation, and stroke. RESULTS: RT recipients were younger than dialysis and patients with CKD (61±10 vs 68±12 vs 78±8.2 years, p<0.001). Patients with RT less frequently had severe left ventricular dysfunction compared with dialysis and CKD groups (6.7% vs 14% and 8.5%); however more, often presented with acute coronary syndrome (58% vs 52% and 48%), especially STEMI (all p<0.001). Patients with RT and CKD had lower rates of 30-day MACCE (4.4% and 6.8% vs 11.6%, p<0.001) than the dialysis group. Three-year survival was similar between RT and CKD groups, however was lower in the dialysis group (80% and 83% vs 60%, p<0.001). After adjustment, dialysis was an independent predictor of 30-day MACCE (odds ratio [OR] 1.90, 95% confidence interval [CI] 1.44‒2.50, p<0.001), however RT was not (OR 0.91, CI 0.42‒1.96, p=0.802). Both RT (hazard ratio [HR] 2.07, CI 1.46‒2.95, p<0.001) and dialysis (HR 1.35, CI 1.02‒1.80, p=0.036) heightened the hazard of long-term mortality. CONCLUSIONS: RT recipients have more favourable clinical outcomes following PCI compared with patients on dialysis. However, despite having similar short-term outcomes to patients with CKD, the hazard of long-term mortality is significantly greater for RT recipients.

Utilisation of Chronic Disease and Mental Health Management Services and Cardioprotective Medication Prescriptions in Primary Care for Patients With Cardiovascular Diseases and Cancer: A Cross-Sectional Study.

BACKGROUND: Cardiovascular disease (CVD) is a leading cause of morbidity and mortality among cancer survivors. Mental health is considered an important risk factor affecting the treatment of cardiovascular disease. However, little is known about the use of secondary prevention strategies for CVD in patients with both cancer and CVD. This study aimed to compare the utilisation of primary care chronic disease management plans, mental health care and guideline-indicated cardioprotective medications among CVD patients with and without cancer. METHODS: Retrospective cross-sectional study utilising clinical data of patients with CVD from 50 Australian primary care practices. Outcomes included the use of chronic disease management plans, mental health care, guideline-indicated cardioprotective medications and influenza vaccination. Logistic regression, accounting for demographic and clinical covariates and clustering effects by practices, was used to compare the two groups. RESULTS: Of the 15,040 patients with CVD, 1,486 patients (9.9%) concurrently had cancer. Patients with cancer, compared to those without, were older (77.6 vs 71.8 years, p<0.001), more likely to drink alcohol (62.6% vs 55.7%, p<0.001), have lower systolic (130.3±17.8 vs 132.5±21.1 mmHg, p<0.001) and diastolic (72.2±11 vs 75.3±34 mmHg, p<0.001) blood pressure. Although suboptimal for both groups, patients with cancer were significantly more likely to have general practice management plans (GPMPs) (51.4% vs 43.2%, p<0.001), coordination of team care arrangements (TCAs) (46.2% vs 37.0%, p<0.001), have a review of either GPMP or TCA (42.8% vs 34.7%, p<0.001), have a mental health treatment consultation (15.4% vs 10.5%, p=0.004) and be prescribed blood pressure-lowering medications (70.1% vs 66.0%, p=0.002). However, there were no statistical differences in the prescription of lipid-lowering or antiplatelet medications. After adjustments for covariates and multiple testing, patients with cancer did not show a difference in GPMPs, TCAs, and a review of either, but were more likely to receive mental health treatment consultations than those without cancer (odds ratio 1.76; 95% confidence interval 1.42-2.19). CONCLUSIONS: Less than half of patients with CVD had a GPMP, TCA or review of either. Although those patients with cancer were more likely to receive these interventions, still around half the patients did not. Medicare-funded GPMPs, TCAs and a review of either GPMP or TCA were underutilised, and future studies should seek to identify ways of improving access to these services.

The Potential Antidepressant Compound Org 34167 Modulates HCN Channels Via a Novel Mode of Action.

Org 34167 is a small molecule hyperpolarization-activated cyclic nucleotide-gated (HCN) channel modulator that has been trialed in humans for its potential antidepressant activity. The precise action of Org 34167 is not fully understood. Here we use two-electrode voltage clamp recordings and an allosteric model to explore the interaction of Org 34167 with human HCN1 channels. The impact of Org 34167 on channel function included a hyperpolarizing shift in activation voltage dependence and a slowing of activation kinetics. Furthermore, a reduction in the maximum open probability at extreme hyperpolarization argued for an additional voltage-independent mechanism. Org 34167 had a similar impact on a truncated HCN1 channel lacking the C-terminal nucleotide binding domain, thus ruling out an interaction with this domain. Fitting a gating model, derived from a 10-state allosteric scheme, predicted that Org 34167 strongly reduced the equilibrium constant for the voltage-independent pore domain to favor a closed pore, as well as reducing the voltage sensing domain-pore domain coupling and shifting the zero voltage equilibrium constant of the voltage sensing domain to favor the inactive state. SIGNIFICANCE STATEMENT: The brain penetrant small molecule Org 34167 has been reported to have an antidepressant action by targeting HCN channels; however, its mode of action is unknown. We used heterologously expressed human HCN1 channels to show that Org 34167 inhibits channel activity by modulating kinetic parameters associated with the channel pore domain, voltage sensing domain, and interdomain coupling.

HCN1 epilepsy: From genetics and mechanisms to precision therapies.

Pathogenic variation in HCN1 is now an established cause of epilepsy and intellectual disability. Variation in HCN1 causes a spectrum of disease with a genotype-phenotype relationship emerging. De novo pathogenic variants that occur in the transmembrane domains of the channel typically cause a cation 'leak' that associates with severe developmental and epileptic encephalopathy (DEE). Genotype-phenotype associations for variants that fall outside of the transmembrane domains are less well established but do include milder forms of epilepsy that can be either de novo or inherited. HCN1 DEE mouse models have been generated which recapitulate the seizures and learning difficulties seen in human patients. These mice have also acted as powerful preclinical models which share pharmacoresponsiveness with human HCN1 DEE patients. Data from these mouse models support the conclusion that anti-seizure medications with sodium channel block as their primary mechanism of action should be used with caution in HCN1 DEE. Other comorbidities of HCN1 DEE including retinal dysfunction have also been modelled in HCN1 DEE mice, suggesting HCN1 variants can cause a dramatically reduced sensitivity to light with limited ability to process temporal information. Our understanding of the genetics and pathophysiological mechanisms underlying HCN1 epilepsy has progressed significantly and is already influencing therapy. However, more research effort is needed to fully understand the natural histories of HCN1 epilepsies and to develop precision therapeutic approaches.

Fundamental Neurochemistry Review: GABAA receptor neurotransmission and epilepsy: Principles, disease mechanisms and pharmacotherapy.

Epilepsy is a common neurological disorder associated with alterations of excitation-inhibition balance within brain neuronal networks. GABAA receptor neurotransmission is the most prevalent form of inhibitory neurotransmission and is strongly implicated in both the pathophysiology and treatment of epilepsy, serving as a primary target for antiseizure medications for over a century. It is now established that GABA exerts a multifaceted influence through an array of GABAA receptor subtypes that extends far beyond simply negating excitatory activity. As the role of GABAA neurotransmission within inhibitory circuits is elaborated, this will enable the development of precision therapies that correct the network dysfunction underlying epileptic pathology.

Transcriptional regulation of MGE progenitor proliferation by PRDM16 controls cortical GABAergic interneuron production.

The mammalian cortex is populated by neurons derived from neural progenitors located throughout the embryonic telencephalon. Excitatory neurons are derived from the dorsal telencephalon, whereas inhibitory interneurons are generated in its ventral portion. The transcriptional regulator PRDM16 is expressed by radial glia, neural progenitors present in both regions; however, its mechanisms of action are still not fully understood. It is unclear whether PRDM16 plays a similar role in neurogenesis in both dorsal and ventral progenitor lineages and, if so, whether it regulates common or unique networks of genes. Here, we show that Prdm16 expression in mouse medial ganglionic eminence (MGE) progenitors is required for maintaining their proliferative capacity and for the production of proper numbers of forebrain GABAergic interneurons. PRDM16 binds to cis-regulatory elements and represses the expression of region-specific neuronal differentiation genes, thereby controlling the timing of neuronal maturation. PRDM16 regulates convergent developmental gene expression programs in the cortex and MGE, which utilize both common and region-specific sets of genes to control the proliferative capacity of neural progenitors, ensuring the generation of correct numbers of cortical neurons.

Transforming blood pressure control in primary care through a novel remote decision support strategy based on wearable blood pressure monitoring: The NEXTGEN-BP randomized trial protocol.

BACKGROUND: Despite high blood pressure being the leading preventable risk factor for death, only 1 in 3 patients achieve target blood pressure control. Key contributors to this problem are clinical inertia and uncertainties in relying on clinic blood pressure measurements to make treatment decisions. METHODS: The NEXTGEN-BP open-label, multicenter, randomized controlled trial will investigate the efficacy, safety, acceptability and cost-effectiveness of a wearable blood pressure monitor-based care strategy for the treatment of hypertension, compared to usual care, in lowering clinic blood pressure over 12 months. NEXTGEN-BP will enroll 600 adults with high blood pressure, treated with 0 to 2 antihypertensive medications. Participants attending primary care practices in Australia will be randomized 1:1 to the intervention of a wearable-based remote care strategy or to usual care. Participants in the intervention arm will undergo continuous blood pressure monitoring using a wrist-wearable cuffless device (Aktiia, Switzerland) and participate in 2 telehealth consultations with their primary care practitioner (general practitioner [GP]) at months 1 and 2. Antihypertensive medication will be up-titrated by the primary care practitioner at the time of telehealth consults should the percentage of daytime blood pressure at target over the past week be <90%, if clinically tolerated. Participants in the usual care arm will have primary care consultations according to usual practice. The primary outcome is the difference between intervention and control in change in clinic systolic blood pressure from baseline to 12 months. Secondary outcomes will be assessed at month 3 and month 12, and include acceptability to patients and practitioners, cost-effectiveness, safety, medication adherence and patient engagement. CONCLUSIONS: NEXTGEN-BP will provide evidence for the effectiveness and safety of a new paradigm of wearable cuffless monitoring in the management of high blood pressure in primary care. TRIAL REGISTRATION: ACTRN12622001583730.