Physiologically Based Pharmacokinetic Modeling for Maribavir to Inform Dosing in Drug-Drug Interaction Scenarios with CYP3A4 Inducers and Inhibitors

Maribavir, an orally available antiviral agent, has been approved in multiple countries for the treatment of patients with refractory post-transplant cytomegalovirus (CMV) infection and/or disease. Maribavir is primarily metabolized by CYP3A4; coadministration with CYP3A4 inducers and inhibitors may significantly alter maribavir exposure, thereby affecting its efficacy and safety. The effect of CYP3A4 inducers and inhibitors on maribavir exposure was evaluated based on a drug-drug interaction (DDI) study and physiologically-based pharmacokinetic (PBPK) modeling. The effect of rifampin (a strong inducer of CYP3A4 and moderate inducer of CYP1A2), administered at a 600 mg dose once daily, on maribavir pharmacokinetics was assessed in a clinical phase 1 DDI study in healthy participants. A full PBPK model for maribavir was developed and verified using in vitro and clinical pharmacokinetic data from phase 1 studies. The verified PBPK model was then used to simulate maribavir DDI interactions with various CYP3A4 inducers and inhibitors. The DDI study results showed that coadministration with rifampin decreased the maribavir maximum plasma concentration (Cmax), area under the plasma concentration-time curve (AUC), and trough concentration (Ctrough) by 39%, 60%, and 82%, respectively. Based on the results from the clinical DDI study, the coadministration of maribavir with rifampin is not recommended. The PBPK model did not predict a clinically significant effect of CYP3A4 inhibitors on maribavir exposure; however, it predicted that strong or moderate CYP3A4 inducers, including carbamazepine, efavirenz, phenobarbital, and phenytoin, may reduce maribavir exposure to a clinically significant extent, and may prompt the consideration of a maribavir dosing increase, in accordance with local approved labels and/or regulations.

Mental Imagery in Dreams of Congenitally Blind People

It is unclear to what extent the absence of vision affects the sensory sensitivity for oneiric construction. Similarly, the presence of visual imagery in the mentation of dreams of congenitally blind people has been largely disputed. We investigate the presence and nature of oneiric visuo-spatial impressions by analysing 180 dreams of seven congenitally blind people identified from the online database DreamBank. A higher presence of auditory, haptic, olfactory, and gustatory sensation in dreams of congenitally blind people was demonstrated, when compared to normally sighted individuals. Nonetheless, oneiric visual imagery in reports of congenitally blind subjects was also noted, in opposition to some previous studies, and raising questions about the possible underlying neuro-mechanisms.

Sex differences in alpha-synucleinopathies: a systematic review

Background

Past research indicates a higher prevalence, incidence, and severe clinical manifestations of alpha-synucleinopathies in men, leading to a suggestion of neuroprotective properties of female sex hormones (especially estrogen). The potential pathomechanisms of any such effect on alpha-synucleinopathies, however, are far from understood. With that aim, we undertook to systematically review, and to critically assess, contemporary evidence on sex and gender differences in alpha-synucleinopathies using a bench-to-bedside approach.

Methods

In this systematic review, studies investigating sex and gender differences in alpha-synucleinopathies (Rapid Eye Movement (REM) Behavior Disorder (RBD), Parkinson's Disease (PD), Dementia with Lewy Bodies (DLB), Multiple System Atrophy (MSA)) from 2012 to 2022 were identified using electronic database searches of PubMed, Embase and Ovid.

Results

One hundred sixty-two studies were included; 5 RBD, 6 MSA, 20 DLB and 131 PD studies. Overall, there is conclusive evidence to suggest sex-and gender-specific manifestation in demographics, biomarkers, genetics, clinical features, interventions, and quality of life in alpha-synucleinopathies. Only limited data exists on the effects of distinct sex hormones, with majority of studies concentrating on estrogen and its speculated neuroprotective effects.

Conclusion

Future studies disentangling the underlying sex-specific mechanisms of alpha-synucleinopathies are urgently needed in order to enable novel sex-specific therapeutics.

Visuo-spatial imagery in dreams of congenitally and early blind: a systematic review

Background

The presence of visual imagery in dreams of congenitally blind people has long been a matter of substantial controversy. We set to systematically review body of published work on the presence and nature of oneiric visuo-spatial impressions in congenitally and early blind subjects across different areas of research, from experimental psychology, functional neuroimaging, sensory substitution, and sleep research.

Methods

Relevant studies were identified using the following databases: EMBASE, MEDLINE and PsychINFO.

Results

Studies using diverse imaging techniques and sensory substitution devices broadly suggest that the "blind" occipital cortex may be able to integrate non-visual sensory inputs, and thus possibly also generate visuo-spatial impressions. Visual impressions have also been reported by blind subjects who had near-death or out-of-body experiences.

Conclusion

Deciphering the mechanistic nature of these visual impression could open new possibility in utilization of neuroplasticity and its potential role for treatment of neurodisability.

Pharmacokinetics and Safety Evaluation of Maribavir in Healthy Japanese and Matched White Participants: A Phase I, Open-Label Study

This phase I study compared pharmacokinetics and safety of maribavir in Japanese and White participants, and evaluated dose proportionality in Japanese participants. Under fasting conditions, 12 healthy adult participants of Japanese descent and 12 matched White participants received a single 400-mg dose of maribavir. Japanese participants received 2 further doses of maribavir: 200 mg and 800 mg, or 800 mg and 200 mg, separated by a ≥72-hour washout period. Serial blood samples were collected up to 24 hours after dosing for pharmacokinetic assessments. Following the 400-mg dose, the geometric mean ratios (90% confidence interval) of Japanese versus White participants were 110% (91.7%-133%) for maximum plasma concentration, 122% (96.8%-155%) for area under the plasma concentration-time curve (AUC) from time of dosing to the last measurable concentration, and 125% (98.0%-160%) for AUC extrapolated to infinity. In Japanese participants, maribavir AUC extrapolated to infinity and AUC from time of dosing to the last measurable concentration increased in a dose-proportional fashion over 200-800 mg; maximum plasma concentration increased less than dose proportionally. Seven participants reported treatment-emergent adverse events (TEAEs; Japanese participants, 400 mg: 2 [16.7%], 200 mg: 1 [8.3%]; White participants, 400 mg: 4 [33.3%]), all mild and most commonly dysgeusia. No serious TEAEs or TEAEs leading to discontinuation were reported. This study demonstrated higher maribavir systemic exposure in Japanese than White participants and similar safety outcomes. This difference in exposure is not considered clinically important and its significance remains to be determined.

Maribavir Pharmacokinetics and Safety in Participants With Moderate Hepatic Impairment: A Phase 1, Open-Label, Single-Dose, Parallel Group Study

Maribavir, an orally bioavailable antiviral, has shown superior activity against posttransplant cytomegalovirus infection compared with conventional antivirals. It is primarily metabolized in the liver. This open-label, single-center study evaluated the effect of hepatic impairment on the pharmacokinetics of maribavir in nontransplant participants. A single 200-mg dose of maribavir was administered orally under fasting conditions to participants with moderate hepatic impairment (Child-Pugh class B) (n = 10) and healthy controls (n = 10) matched for age, weight, sex, and smoking status. Compared with participants with normal hepatic function, maximum plasma concentration (C_max ) and area under the plasma concentration-time curve (AUC) from time 0 to infinity values for maribavir in participants with moderate hepatic impairment were 1.346-fold (90%CI of geometric mean ratio, 1.091-1.660) and 1.261-fold (0.889-1.787) higher, respectively. However, C_max and AUC values for unbound maribavir were comparable. For VP 44469, the main metabolite of maribavir, the C_max and AUC from time 0 to infinity values were 1.190-fold (0.836-1.693) and 1.309-fold (1.007-1.702) higher, respectively, in participants with moderate hepatic impairment. In total, 7 mild treatment-emergent adverse events were reported, all in the moderate hepatic impairment group. Dysgeusia was the most frequently reported treatment-emergent adverse event, at a frequency of 50%. These results indicated that total maribavir concentrations were mildly increased in participants with moderate hepatic impairment, while unbound concentrations were unaffected. Similar maribavir pharmacokinetics in participants with moderate hepatic impairment and normal hepatic function suggest that dose adjustment may not be required for patients with moderate hepatic impairment.

Gangliosidome of a Human Hippocampus in Temporal Lobe Epilepsy Resolved by High-Resolution Tandem Mass Spectrometry

In this study, we developed a high-resolution tandem mass spectrometry (HR MS) approach to assess presumed changes in gangliosidome of a human hippocampus affected by temporal lobe epilepsy (TLE) in comparison with a normal hippocampus. Gangliosides, membrane glycolipids, are particularly diverse and abundant in the human brain, and participate in ion transport and modulation of neuronal excitability. Changes in structural ganglioside pattern potentially linked to TLE molecular pathogenesis have not been explored in detail. Aiming to characterize TLE-specific gangliosidome, we analyzed the native gangliosides purified from a human hippocampal tissue sample affected by TLE and a control hippocampus using HR MS. Marked differences of ganglioside expression were shown in TLE vs. control, particularly with respect to the sialylation degree of components, discovered as a characteristic feature of TLE. Another major finding is the occurrence of tetrasialofucogangliosides in TLE and species modified by either O-acetylation or CH3COO−. Structural analysis by higher-energy collisional dissociation (HCD) MS/MS gave rise to fragmentation patterns implying that the GQ1b (d18:1/18:0) isomer is specifically associated with TLE. Further investigation in a larger sample is needed in order to confirm the discovery of ganglioside structures specifically expressed in human TLE and to provide information on the probable role of gangliosides in the molecular events underlying seizures.

Relevance of sleep and associated structural changes in GBA1 mouse to human rapid eye movement behavior disorder

Rapid eye movement (REM) sleep behaviour disorder (RBD) is a REM parasomnia that often predicts the later occurrence of alpha-synucleinopathies. Variants in the gene encoding for the lysosomal enzyme glucocerebrosidase, GBA, strongly increase the risk of RBD. In a GBA1-mouse model recently shown to mimic prodromal stages of α-synucleinopathy, we now demonstrate striking REM and NREM electroencephalographic sleep abnormalities accompanied by distinct structural changes in the more widespread sleep neurocircuitry.

The Signature of Moderate Perinatal Hypoxia on Cortical Organization and Behavior: Altered PNN-Parvalbumin Interneuron Connectivity of the Cingulate Circuitries

This study was designed in a rat model to determine the hallmarks of possible permanent behavioral and structural brain alterations after a single moderate hypoxic insult. Eighty-two Wistar Han (RccHan: WIST) rats were randomly subjected to hypoxia (pO2 73 mmHg/2 h) or normoxia at the first postnatal day. The substantially increased blood lactate, a significantly decreased cytochrome-C-oxygenase expression in the brain, and depleted subventricular zone suggested a high vulnerability of subset of cell populations to oxidative stress and consequent tissue response even after a single, moderate, hypoxic event. The results of behavioral tests (open-field, hole-board, social-choice, and T-maze) applied at the 30–45th and 70–85th postnatal days revealed significant hyperactivity and a slower pace of learning in rats subjected to perinatal hypoxia. At 3.5 months after hypoxic insult, the histochemical examination demonstrated a significantly increased number of specific extracellular matrix—perineuronal nets and increased parvalbumin expression in a subpopulation of interneurons in the medial and retrosplenial cingulate cortex of these animals. Conclusively, moderate perinatal hypoxia in rats causes a long-lasting reorganization of the connectivity in the cingulate cortex and consequent alterations of related behavioral and cognitive abilities. This non-invasive hypoxia model in the rat successfully and complementarily models the moderate perinatal hypoxic injury in fetuses and prematurely born human babies and may enhance future research into new diagnostic and therapeutic strategies for perinatal medicine.

Periodic limb movements during sleep: a narrative review

Objective

Using narrative review techniques, this paper evaluates the evidence for separable underlying patho-mechanisms of periodic limb movements (PLMs) to separable PLM motor patterns and phenotypes, in order to elucidate potential new treatment modalities.

Background

Periodic limb movement disorder (PLMD) is estimated to occur in 5–8% of the paediatric population and 4–11% of the general adult population. Due to significant sleep fragmentation, PLMD can lead to functional impairment, including hyperactivity and delayed language development in children, and poor concentration and work performance in adults. Longitudinal data demonstrate that those with PLMD are at greater risk of depression and anxiety, and a 4-fold greater risk of developing dementia. PLMD has been extensively studied over the past two decades, and several key insights into the genetic, pathophysiological, and neural correlates have been proposed. Amongst these proposals is the concept of separable PLM phenotypes, proposed on the basis of nocturnal features such as the ratio of limb movements and distribution throughout the night. PLM phenotype and presentation, however, varies significantly depending on the scoring utilized and the nocturnal features examined, across age, and co-morbid clinical conditions. Furthermore, associations between these phenotypes with major neurologic and psychiatric disorders remain controversial.

Methods

In order to elucidate potential divergent biological pathways that may help clarify important new treatment modalities, this paper utilizes narrative review and evaluates the evidence linking PLM motor patterns and phenotypes with hypothesised underlying patho-mechanisms. Distinctive, underlying patho-mechanisms include: a pure motor mechanism originating in the spinal cord, iron deficiency, dopamine system dysfunction, thalamic glutamatergic hyperactivity, and a more cortical-subcortical interplay. In support of the latter hypothesis, PLM rhythmicity appears tightly linked to the microarchitecture of sleep, not dissimilarly to the apnoeic/hypopneic events seen in obstructive sleep apnea (OSA).

Conclusions

This review closes with a proposal for greater investigation into the identification of potential, divergent biological pathways. To do so would require prospective, multimodal imaging clinical studies which may delineate differential responses to treatment in restless legs syndrome (RLS) without PLMS and PLMS without RLS. This could pave the way toward important new treatment modalities.

Pharmacokinetics, Safety, and Tolerability of SHP465 Mixed Amphetamine Salts After Administration of Multiple Daily Doses in Children Aged 4-5 Years with Attention-Deficit/Hyperactivity Disorder

BACKGROUND

Given the limited treatment options for younger children with attention-deficit/hyperactivity disorder (ADHD), a clinical study for SHP465 treatment was warranted.

OBJECTIVES

We aimed to evaluate the pharmacokinetics, safety, and tolerability of SHP465 mixed amphetamine salts (MAS) 6.25 mg after multiple once-daily doses in children aged 4-5 years with ADHD.

METHODS

In this open-label multicenter study, SHP465 MAS 6.25 mg once daily was administered for 28 days to children aged 4-5 years with ADHD; baseline ADHD Rating Scale-5 total score ≥ 28 (boys) or ≥ 24 (girls) and Clinical Global Impression-Severity scale score ≥ 4. Blood samples were collected in the pharmacokinetic-rich group predose on day 1 week 1 and day 7 week 4 (predose, postdose at 2, 5, 8, 12, 16, 24, and 48 hours); and in the pharmacokinetic-sparse group predose on day 1 weeks 1, 2, and 3 and 24 hours postdose on day 7 week 4 . Key pharmacokinetic parameters included maximum plasma drug concentration (C_max), plasma trough drug concentration, time to C_max during a dosing interval (t_max), area under the concentration-time curve from time 0 to time of last collected sample, area under the concentration-time curve over the dosing interval (24 h) at steady state (AUC_tau,ss), first-order rate constant associated with the terminal phase of elimination, terminal half-life (t_1/2), total clearance of drug from plasma after oral administration, and apparent volume of distribution at steady state. Safety endpoints included treatment-emergent adverse events and vital signs.

RESULTS

Mean ± standard deviation age and body mass index of 24 participants (66.7% male) were 4.8 ± 0.41 years and 17.2 ± 3.18 kg/m², respectively. The most common ADHD was the combined presentation (91.7%); ratings were 50% markedly ill and 45.8% moderately ill on the Clinical Global Impression-Severity scale. Plasma d-amphetamine and l-amphetamine steady state was attained by predose on treatment day 8, consistent with the half-life. Peak steady-state plasma concentration (median t_max) for both d-amphetamine and l-amphetamine occurred at 7.92 h postdose on day 7 week 4 and thereafter declined monoexponentially, with a geometric mean t_1/2 of 10.4 and 12.3 h for d-amphetamine and l-amphetamine, respectively. For both d-amphetamine and l-amphetamine, C_max and AUC_tau,ss were comparable between children aged 4 years (n = 3) and children aged 5 years (n = 8) regardless of sex. In total, 14 treatment-emergent adverse events were reported by 45.8% (11/24) of participants. Five treatment-emergent adverse events, reported for four (16.7%) participants, were considered treatment related; affect lability occurred in two (8.3%) participants, and insomnia, accidental overdose, and increased blood pressure each occurred in one (4.2%) participant.

CONCLUSIONS

In children aged 4-5 years with ADHD, following multiple once-daily administrations of SHP465 MAS 6.25 mg, the pharmacokinetic profile of plasma d-amphetamine and l-amphetamine was generally consistent among participants. Between-individual variability of plasma d-amphetamine and l-amphetamine steady-state exposure was low to moderate. SHP465 MAS was generally well tolerated in this study.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03327402 (31 October, 2017).

Plasma Membrane Calcium ATPase-Neuroplastin Complexes Are Selectively Stabilized in GM1-Containing Lipid Rafts

The recent identification of plasma membrane (Ca²⁺)-ATPase (PMCA)-Neuroplastin (Np) complexes has renewed attention on cell regulation of cytosolic calcium extrusion, which is of particular relevance in neurons. Here, we tested the hypothesis that PMCA-Neuroplastin complexes exist in specific ganglioside-containing rafts, which could affect calcium homeostasis. We analyzed the abundance of all four PMCA paralogs (PMCA1-4) and Neuroplastin isoforms (Np65 and Np55) in lipid rafts and bulk membrane fractions from GM2/GD2 synthase-deficient mouse brains. In these fractions, we found altered distribution of Np65/Np55 and selected PMCA isoforms, namely PMCA1 and 2. Cell surface staining and confocal microscopy identified GM1 as the main complex ganglioside co-localizing with Neuroplastin in cultured hippocampal neurons. Furthermore, blocking GM1 with a specific antibody resulted in delayed calcium restoration of electrically evoked calcium transients in the soma of hippocampal neurons. The content and composition of all ganglioside species were unchanged in Neuroplastin-deficient mouse brains. Therefore, we conclude that altered composition or disorganization of ganglioside-containing rafts results in changed regulation of calcium signals in neurons. We propose that GM1 could be a key sphingolipid for ensuring proper location of the PMCA-Neuroplastin complexes into rafts in order to participate in the regulation of neuronal calcium homeostasis.

Neuroplastin in human cognition: review of literature and future perspectives

Synaptic glycoprotein neuroplastin is involved in synaptic plasticity and complex molecular events underlying learning and memory. Studies in mice and rats suggest that neuroplastin is essential for cognition, as it is needed for long-term potentiation and associative memory formation. Recently, it was found that some of the effects of neuroplastin are related to regulation of calcium homeostasis through interactions with plasma membrane calcium ATPases. Neuroplastin is increasingly seen as a key factor in complex brain functions, but studies in humans remain scarce. Here we summarize present knowledge about neuroplastin in human tissues and argue its genetic association with cortical thickness, intelligence, schizophrenia, and autism; specific immunolocalization depicting hippocampal trisynaptic pathway; potential role in tissue compensatory response in neurodegeneration; and high, almost housekeeping, level of spatio-temporal gene expression in the human brain. We also propose that neuroplastin acts as a housekeeper of neuroplasticity, and that it may be considered as an important novel cognition-related molecule in humans. Several promising directions for future investigations are suggested, which may complete our understanding of neuroplastin actions in molecular basis of human cognition.

Who's in, who's out? Re-evaluation of lipid raft residents

Lipid rafts, membrane microdomains enriched with (glyco)sphingolipids, cholesterol, and select proteins, act as cellular signalosomes. Various methods have been used to separate lipid rafts from bulk (non‐raft) membranes, but most often, non‐ionic detergent Triton X‐100 has been used in their isolation. However, Triton X‐100 is a reported disruptor of lipid rafts. Histological evidence confirmed raft disruption by Triton X‐100, but remarkably revealed raft stability to treatment with a related polyethylene oxide detergent, Brij O20. We report isolation of detergent‐resistant membranes from mouse brain using Brij O20 and its use to determine the distribution of major mammalian brain gangliosides, GM1, GD1a, GD1b and GT1b. A different distribution of gangliosides—classically used as a raft marker—was discovered using Brij O20 versus Triton X‐100. Immunohistochemistry and imaging mass spectrometry confirm the results. Use of Brij O20 results in a distinctive membrane distribution of gangliosides that is not all lipid raft associated, but depends on the ganglioside structure. This is the first report of a significant proportion of gangliosides outside raft domains. We also determined the distribution of proteins functionally related to neuroplasticity and known to be affected by ganglioside environment, glutamate receptor subunit 2, amyloid precursor protein and neuroplastin and report the lipid raft populations of these proteins in mouse brain tissue. This work will enable more accurate lipid raft analysis with respect to glycosphingolipid and membrane protein composition and lead to improved resolution of lipid–protein interactions within biological membranes.

Clinical Pharmacology Worldwide: A Global Health Perspective

Low- and middle-income countries (LMICs) have the highest rates of mortality and morbidity globally, but lag behind high-income countries in the number of clinical trials and trained researchers, as well as research data pertaining to their populations. Lack of local clinical pharmacology and pharmacometrics expertise, limited training opportunities, and lack of local genomic data may contribute to health inequalities and limit the application of precision medicine. Continuing to develop health care infrastructure, including well-designed clinical pharmacology training and data collection in LMICs, can help address these challenges. International collaboration aimed at improving training and infrastructure and encouraging locally driven research and clinical trials will be of benefit. This review describes several examples where clinical pharmacology expertise could be leveraged, including opportunities for pharmacogenomic expertise that could drive improved recommendations for clinical guidelines. Also described are clinical pharmacology and pharmacometrics training programs in Africa, and the personal experience of a Tanzanian researcher currently on a training sabbatical in the United States, as illustrative examples of how training in clinical pharmacology can be effectively implemented in LMICs. These training efforts will benefit from advocacy for employment opportunities and career development pathways for clinical pharmacologists that are gradually being recognized and developed in LMICs. Clinical pharmacologists have a key role to play in global health, and development of training and research infrastructure to advance this expertise in LMICs will be of tremendous benefit.

Obstructive sleep apnea and multiple facets of a neuroinflammatory response: a narrative review

Background

Obstructive sleep apnea (OSA) is a chronic, highly prevalent, multi-system and sleep disorder, which may contribute to cognitive impairment and a variety of structural and neurophysiologic changes. The focus on OSA is warranted given its recognized links with major psychiatric and neurologic disorders, including Alzheimer’s disease. Some preliminary studies suggest a dual effect of the inflammatory response in OSA. Neuroinflammation may present with initial, potentially adaptive and homeostatic, and later, a more distinctly maladaptive, precipitating and perpetuating role.

Objective

We here propose and argue in favour of the inflammatory process in the brain as a likely binding mechanism behind at least some effects that OSA may have on the brain and its function. Several OSA-triggered molecular and cellular events, that could lead to a neurodegenerative cascade, are similarly discussed.

Methods

This perspective reviews the body of literature that investigates potential links between the inflammatory processes in the brain and the OSA. A special emphasis is placed on a potential role for neuroplastin, a novel transmembrane synaptic protein involved in the neuroplasticity and known to be differentially regulated in the OSA.

Conclusions

The intricate interplay between neuroinflammation and other mechanistic correlates of OSA add to the evidence that neuroinflammation may be a key target for future therapeutic strategies in a number of comorbid disorders. The future studies will need to answer whether it is sleep fragmentation (SF) or intermittent hypoxia (IH) which may drive any such neuroinflammation.

The innate immune toll-like-receptor-2 modulates the depressogenic and anorexiolytic neuroinflammatory response in obstructive sleep apnoea

The increased awareness of obstructive sleep apnoea’s (OSA) links to Alzheimer’s disease and major psychiatric disorders has recently directed an intensified search for their potential shared mechanisms. We hypothesised that neuroinflammation and the microglial TLR2-system may act as a core process at the intersection of their pathophysiology. Moreover, we postulated that inflammatory-response might underlie development of key behavioural and neurostructural changes in OSA. Henceforth, we set out to investigate effects of 3 weeks’ exposure to chronic intermittent hypoxia in mice with or without functional TRL2 (TLR2^+/+, C57BL/6-Tyrc-Brd-Tg(Tlr2-luc/gfp)Kri/Gaj;TLR2^−/−,C57BL/6-Tlr2tm1Kir). By utilising multimodal imaging in this established model of OSA, a discernible neuroinflammatory response was demonstrated for the first time. The septal nuclei and forebrain were shown as the initial key seed-sites of the inflammatory cascade that led to wider structural changes in the associated neurocircuitry. Finally, the modulatory role for the functional TLR2-system was suggested in aetiology of depressive, anxious and anorexiolytic symptoms in OSA.

Evaluation of the Effect of Maribavir on Cardiac Repolarization in Healthy Participants: Thorough QT/QTc Study

Maribavir is an orally bioavailable benzimidazole riboside in clinical development for treatment of cytomegalovirus infection in patients who undergo transplantation. Maribavir was evaluated in a thorough QT (TQT) study to determine any effects on cardiac repolarization. The effect of maribavir 100 and 1,200 mg oral doses on the baseline-adjusted and placebo-adjusted corrected QT (QTc) interval (delta delta QTc (ddQTc)) and other electrocardiogram (ECG) parameters was assessed in a randomized, phase I, placebo-controlled, four-period crossover study in healthy participants (men and women ages 18-50 years). Additionally, maribavir pharmacokinetics, safety, and tolerability were investigated. Moxifloxacin (400 mg) was used as a positive control to demonstrate the study's ability to detect QT prolongation. Digital 12-lead Holter ECG monitoring was performed over 22 hours following study drug administration. Individual, Fridericia's, and Bazett's QTc intervals were calculated. Of 52 randomized participants (29 ± 8.1 years old; 31 men (60%)), 50 (96%) completed the study. For both 100-mg and 1200-mg doses of maribavir, analysis of ddQTc demonstrated that the upper bound of the two-sided 90% confidence interval was below the 10-ms threshold at all time points. The concentration-effect analysis demonstrated no relationship between ddQTc and plasma concentrations of maribavir (and its metabolite). There were no clinically meaningful changes in heart rate and systolic blood pressure. The most common adverse event was dysgeusia; no serious adverse events were reported. This TQT study demonstrated that maribavir did not have impact on cardiac repolarization.

Safety and immunogenicity of a seasonal trivalent inactivated split influenza vaccine: a double blind, phase III randomized clinical trial in healthy Serbian adults

This study was a phase III, multicenter, double-blind, randomized, placebo-controlled trial to evaluate the safety and immunogenicity of a seasonal trivalent split, inactivated influenza vaccine (TIV) in healthy Serbian adults between the ages of 18 and 65 years. This egg-based vaccine was manufactured by the Institute of Virology, Vaccines and Sera, Torlak, Belgrade, Serbia. A total of 480 participants were assigned randomly in a ratio of 2:1 to receive a single intramuscular dose (0.5 ml) of the vaccine (15 µg of hemagglutinin per strain) or placebo (phosphate-buffered saline). Participants were monitored for safety, including solicited and unsolicited adverse events (AEs) and serious adverse events (SAEs). No SAEs related to vaccination were reported. Injection site pain (51.3%), injection site tenderness (40.4%), tiredness (17.0%), and headache (15.1%) were the most commonly reported solicited events in the vaccine group. Incidence of related unsolicited AEs was low (1.3%) among vaccinees. Hemagglutinin inhibition (HAI) titers were measured before and 21 days after vaccination in 151 participants. Overall, HAI seroconversion rates to H1 and H3 were observed in 90.1% and 76.2% of vaccinees, respectively. For B antigen, it was 51.5%, likely due to high pre-vaccination titers. Post-vaccination seroprotection rates were in the range of 78.2-95.0% for the three antigens. Post-vaccination geometric mean titers (GMT) were at least 3.8 times higher than baseline levels for all the three strains among vaccinees. Overall, the study showed that the vaccine was safe and well tolerated, and induced a robust immune response against all three vaccine strains. ClinicalTrials.gov identifier: NCT02935192, October 17, 2016.

Effects of Maribavir on P-Glycoprotein and CYP2D6 in Healthy Volunteers

Maribavir is an investigational drug being evaluated in transplant recipients with cytomegalovirus infection. To understand potential drug-drug interactions, we examined the effects of multiple doses of maribavir on cytochrome P450 (CYP) 2D6 and P-glycoprotein (P-gp) activity using probe substrates in healthy volunteers. During this phase 1 open-label study (NCT02775240), participants received the probe substrates digoxin (0.5 mg) and dextromethorphan (30 mg) before and after maribavir (400 mg twice daily for 8 days). Serial plasma samples were analyzed for digoxin, dextromethorpha, dextrorphan, and maribavir concentrations. Pharmacokinetic parameters were calculated (noncompartmental analysis) and analyzed with a linear mixed-effects model for treatment comparison to estimate geometric mean ratios (GMRs) and 90% confidence intervals (CIs). CYP2D6 polymorphisms were genotyped using polymerase chain reaction. Overall, 17 of 18 participants (94.4%) completed the study. All participants were genotyped as CYP2D6 intermediate/extensive metabolizers. GMR (90%CI) of digoxin Cmax , AUClast , and AUC0-∞ with and without maribavir was 1.257 (1.139-1.387), 1.187 (1.088-1.296), and 1.217 (1.110-1.335), respectively, outside the "no-effect" window (0.8-1.25). GMR (90%CI) of dextromethorphan AUClast and AUClast ratio of dextromethorphan/dextrorphan were 0.877 (0.692-1.112) and 0.901 (0.717-1.133), respectively, marginally outside the no-effect window, although large variability was observed in these pharmacokinetic parameters. Pharmacokinetic parameters of dextrorphan were unaffected. Maribavir inhibited P-gp activity but did not affect CYP2D6 activity. Maribavir's effect on the pharmacokinetics of P-gp substrates should be evaluated individually, and caution should be exercised with P-gp substrates with narrow therapeutic windows.

Neuronal Signaling by Thy-1 in Nanodomains With Specific Ganglioside Composition: Shall We Open the Door to a New Complexity?

Thy-1 is a small membrane glycoprotein and member of the immunoglobulin superfamily of cell adhesion molecules. It is abundantly expressed in many cell types including neurons and is anchored to the outer membrane leaflet via a glycosyl phosphatidylinositol tail. Thy-1 displays a number of interesting properties such as fast lateral diffusion, which allows it to get in and out of membrane nanodomains with different lipid composition. Thy-1 displays a broad expression in different cell types and plays confirmed roles in cell development, adhesion and differentiation. Here, we explored the functions of Thy-1 in neuronal signaling, initiated by extracellular binding of α_Vβ₃ integrin, may strongly dependent on the lipid content of the cell membrane. Also, we assort literature suggesting the association of Thy-1 with specific components of lipid rafts such as sialic acid containing glycosphingolipids, called gangliosides. Furthermore, we argue that Thy-1 positioning in nanodomains may be influenced by gangliosides. We propose that the traditional conception of Thy-1 localization in rafts should be reconsidered and evaluated in detail based on the potential diversity of neuronal nanodomains.

Hippocampal expression of cell-adhesion glycoprotein neuroplastin is altered in Alzheimer's disease

Cell‐adhesion glycoprotein neuroplastin (Np) is involved in the regulation of synaptic plasticity and balancing hippocampal excitatory/inhibitory inputs which aids in the process of associative memory formation and learning. Our recent findings show that neuroplastin expression in the adult human hippocampus is specifically associated with major hippocampal excitatory pathways and is related to neuronal calcium regulation. Here, we investigated the hippocampal expression of brain‐specific neuroplastin isoform (Np65), its relationship with amyloid and tau pathology in Alzheimer's disease (AD), and potential involvement of neuroplastin in tissue response during the disease progression. Np65 expression and localization was analysed in six human hippocampi with confirmed AD neuropathology, and six age‐/gender‐matched control hippocampi by imunohistochemistry. In AD cases with shorter disease duration, the Np65 immunoreactivity was significantly increased in the dentate gyrus (DG), Cornu Ammonis 2/3 (CA2/3), and subiculum, with the highest level of Np expression being located on the dendrites of granule cells and subicular pyramidal neurons. Changes in the expression of neuroplastin in AD hippocampal areas seem to be related to the progression of disease. Our study suggests that cell‐adhesion protein neuroplastin is involved in tissue reorganization and is a potential molecular marker of plasticity response in the early neurodegeneration process of AD.

Safety and immunogenicity of a seasonal trivalent inactivated split influenza vaccine: a phase I randomized clinical trial in healthy Serbian adults

This study was a phase I double-blind, randomized, placebo-controlled trial to evaluate the safety and immunogenicity of a Serbian-produced seasonal trivalent split, inactivated influenza vaccine in healthy adults. The vaccine was manufactured in eggs by the Torlak Institute of Virology, Vaccines and Sera, Belgrade, Serbia and contained A/H1N1, A/H3N2 and B viruses. The clinical trial took place at the Clinical Center of Serbia in Belgrade. Sixty healthy volunteers, aged 18-45 years, were enrolled in the trial. On the day of immunization, volunteers were randomly assigned to receive either a single dose of the trivalent seasonal influenza vaccine (15 μg of hemagglutinin per strain) or placebo (phosphate-buffered saline). Subjects were monitored for adverse events through a clinical history and physical examination, and blood was taken for testing at screening and on day 8 to assess vaccine safety. Serum samples obtained before and 21 days after immunization were tested for influenza antibody titers using hemagglutination-inhibition (HAI) and microneutralization (MN) tests. No serious adverse events were reported. Pain and tenderness at the injection site were the most commonly reported symptoms in both vaccine and placebo groups. Overall, serum HAI responses of fourfold or greater magnitude were observed to H1, H3, and B antigen in 80%, 75%, and 70% of subjects, respectively. Seroprotection rates as measured by HAI were also high (100%, 100% and 86.67%, respectively, for H1, H3 and B). Thus, Torlak's seasonal trivalent influenza vaccine was not associated with adverse events, was well-tolerated and immunogenic. It should be further evaluated in clinical trials to provide sufficient safety and immunogenicity data for licensing in Serbia.

Neuroplastin deletion in glutamatergic neurons impairs selective brain functions and calcium regulation: implication for cognitive deterioration

The cell adhesion molecule neuroplastin (Np) is a novel candidate to influence human intelligence. Np-deficient mice display complex cognitive deficits and reduced levels of Plasma Membrane Ca²⁺ ATPases (PMCAs), an essential regulator of the intracellular Ca²⁺ concentration ([iCa²⁺]) and neuronal activity. We show abundant expression and conserved cellular and molecular features of Np in glutamatergic neurons in human hippocampal-cortical pathways as characterized for the rodent brain. In Nptn^{lox/loxEmx1Cre} mice, glutamatergic neuron-selective Np ablation resulted in behavioral deficits indicating hippocampal, striatal, and sensorimotor dysfunction paralleled by highly altered activities in hippocampal CA1 area, sensorimotor cortex layers I-III/IV, and the striatal sensorimotor domain detected by single-photon emission computed tomography. Altered hippocampal and cortical activities correlated with reduction of distinct PMCA paralogs in Nptn^{lox/loxEmx1Cre} mice and increased [iCa²⁺] in cultured mutant neurons. Human and rodent Np enhanced the post-transcriptional expression of and co-localized with PMCA paralogs in the plasma membrane of transfected cells. Our results indicate Np as essential for PMCA expression in glutamatergic neurons allowing proper [iCa²⁺] regulation and normal circuit activity. Neuron-type-specific Np ablation empowers the investigation of circuit-coded learning and memory and identification of causal mechanisms leading to cognitive deterioration.

Comedications alter drug-induced liver injury reporting frequency: Data mining in the WHO VigiBase™

Polypharmacy is common, and may modify mechanisms of drug-induced liver injury. We examined the effect of these drug-drug interactions on liver safety reports of four drugs highly associated with hepatotoxicity. In the WHO VigiBase™, liver event reports were examined for acetaminophen, isoniazid, valproic acid, and amoxicillin/clavulanic acid. Then, we evaluated the liver event reporting frequency of these 4 drugs in the presence of co-reported medications. Each of the 4 primary drugs was reported as having more than 2000 liver events, and co-reported with more than 600 different medications. Overall, the effect of 2275 co-reported drugs (316 drug classes) on the reporting frequency was analyzed. Decreased liver event reporting frequency was associated with 245 drugs/122 drug classes, including anti-TNFα, opioids, and folic acid. Increased liver event reporting frequency was associated with 170 drugs/82 drug classes; in particular, halogenated hydrocarbons, carboxamides, and bile acid sequestrants. After adjusting for age, gender, and other co-reported drug classes, multiple co-reported drug classes were significantly associated with decreased/increased liver event reporting frequency in a drug-specific/unspecific manner. In conclusion, co-reported medications were associated with changes in the liver event reporting frequency of drugs commonly associated with hepatotoxicity, suggesting that comedications may modify drug hepatic safety.

Mining hidden knowledge for drug safety assessment: topic modeling of LiverTox as a case study

Background

Given the significant impact on public health and drug development, drug safety has been a focal point and research emphasis across multiple disciplines in addition to scientific investigation, including consumer advocates, drug developers and regulators. Such a concern and effort has led numerous databases with drug safety information available in the public domain and the majority of them contain substantial textual data. Text mining offers an opportunity to leverage the hidden knowledge within these textual data for the enhanced understanding of drug safety and thus improving public health.

Methods

In this proof-of-concept study, topic modeling, an unsupervised text mining approach, was performed on the LiverTox database developed by National Institutes of Health (NIH). The LiverTox structured one document per drug that contains multiple sections summarizing clinical information on drug-induced liver injury (DILI). We hypothesized that these documents might contain specific textual patterns that could be used to address key DILI issues. We placed the study on drug-induced acute liver failure (ALF) which was a severe form of DILI with limited treatment options.

Results

After topic modeling of the "Hepatotoxicity" sections of the LiverTox across 478 drug documents, we identified a hidden topic relevant to Hy's law that was a widely-accepted rule incriminating drugs with high risk of causing ALF in humans. Using this topic, a total of 127 drugs were further implicated, 77 of which had clear ALF relevant terms in the "Outcome and management" sections of the LiverTox. For the rest of 50 drugs, evidence supporting risk of ALF was found for 42 drugs from other public databases.

Conclusion

In this case study, the knowledge buried in the textual data was extracted for identification of drugs with potential of causing ALF by applying topic modeling to the LiverTox database. The knowledge further guided identification of drugs with the similar potential and most of them could be verified and confirmed. This study highlights the utility of topic modeling to leverage information within textual drug safety databases, which provides new opportunities in the big data era to assess drug safety.

High daily dose and being a substrate of cytochrome P450 enzymes are two important predictors of drug-induced liver injury

Drug-induced liver injury (DILI) is complicated and difficult to predict. It has been observed that drugs with extensive hepatic metabolism have a higher likelihood of causing DILI. Cytochrome P450 (P450) enzymes are primarily involved in hepatic metabolism. Identifying the associations of DILI with drugs that are P450 substrates, inhibitors, or inducers will be extremely helpful to clinicians during the decision-making process of caring for a patient suspected of having DILI. We collected metabolism data on P450 enzymes for 254 orally administered drugs in the Liver Toxicity Knowledge Base Benchmark Dataset with a known daily dose, and applied logistic regression to identify these associations. We revealed that drugs that are substrates of P450 enzymes have a higher likelihood of causing DILI [odds ratio (OR), 3.99; 95% confidence interval (95% CI), 2.07-7.67; P < 0.0001], which is dose-independent, and drugs that are P450 inhibitors have a higher likelihood of generating DILI only when they are administered at high daily doses (OR, 6.03; 95% CI, 1.32-27.5; P = 0.0098). However, drugs that are P450 inducers are not observed to be associated with DILI (OR, 1.55; 95% CI, 0.65-3.68; P = 0.3246). Our findings will be useful in identifying the suspected medication as a cause of liver injury in clinical settings.

Associations of gender and age with the reporting of drug-induced hepatic failure: data from the VigiBase™

Patient gender and age are considered to be the risk factors for developing drug-induced liver injury (DILI). The aim of this study was to analyze gender and age differences in reporting of drug-induced hepatic failure (HF) to the VigiBase™. VigiBase™ was screened for the HF reports submitted from 2000 to 2009. The information retrieved referred to the suspected drug, age, gender, and a reporting country. Variables were examined by using descriptive statistics and the binomial test. During the 10-year period there were in total 6,370 HF reports from 38 countries. After the exclusion of cases with missing gender data (379 cases), females counted for 54.03%. The largest portion of HF cases referred to age <55 (42.57%) with female predominance (56.81%), whereas age ≥55 (32.57%) showed almost even gender distribution. Overall, there were 941 different drugs or their combinations reported. Females significantly predominated in HF cases associated with analgesics, antiepileptics, antiinflamatory and antirheumatic drugs, psychoanaleptics, antibacterials for systemic use, and antidiabetic drugs. Males were significantly overrepresented in HF cases associated with antivirals for systemic use. Differences between genders and/or age groups in the reporting of drug-induced HF depend on drug and/or drug class but may be influenced by multiple factors.

The influence of sex, ethnicity, and CYP2B6 genotype on bupropion metabolism as an index of hepatic CYP2B6 activity in humans

The effects of sex, ethnicity, and genetic polymorphism on hepatic CYP2B6 (cytochrome P450 2B6) expression and activity were previously demonstrated in vitro. Race/ethnic differences in CYP2B6 genotype and phenotype were observed only in women. To identify important covariates associated with interindividual variation in CYP2B6 activity in vivo, we evaluated these effects in healthy volunteers using bupropion (Wellbutrin SR GlaxoSmithKline, Research Triangle Park, NC) as a CYP2B6 probe substrate. A fixed 150-mg oral sustained-release dose of bupropion was administered to 100 healthy volunteers comprising four sex/ethnicity cohorts (n = 25 each): Caucasian men and Caucasian, African American, and Hispanic women. Blood samples were obtained at 0 and 6 hours postdose for the measurement of serum bupropion (BU) and hydroxybupropion (HB) concentrations. Whole blood was obtained at baseline for CYP2B6 genotyping. To characterize the relationship between CYP2B6 activity and ethnicity, sex, and genotype when accounting for serum BU concentrations (dose-adjusted log(10)-transformed), analysis of covariance model was fitted in which the dependent variable was CYP2B6 activity represented as the log(10)-transformed, metabolic ratio of HB to BU concentrations. Several CYP2B6 polymorphisms were associated with CYP2B6 activity. Evidence of dependence of CYP2B6 activity on ethnicity or genotype-by-ethnicity interactions was not detected in women. These results suggest that CYP2B6 genotype is the most important patient variable for predicting the level of CYP2B6 activity in women, when measured by the metabolism of bupropion. The bupropion metabolic ratio appears to detect known differences in CYP2B6 activity associated with genetic polymorphism, across different ethnic groups. Prospective studies will be needed to validate the use of bupropion as a probe substrate for clinical use.

Cardiovascular risk factors and blood pressure in a primary care unit: Yugoslav Study of the Precursors of Atherosclerosis in School Children (YUSAD)

OBJECTIVES

The presence of cardiovascular risk factors in children may be important in the development of atherosclerosis in adulthood. Adequate control of blood pressure is a cornerstone in atherosclerosis prevention. The aim of the Yugoslav Study of the Precursors of Atherosclerosis in School Children (YUSAD) was to identify risk factors for elevated blood pressure in school children.

METHODS

The YUSAD study is a multicentre follow-up study comprised of two cross-sectional surveys conducted five years apart. At baseline, 10-year-old children (3226 boys and 3074 girls [n=6300]) were randomly selected during periodical visits to primary health care centres. The risk factors measured were heart rate, weight, body mass index (BMI), waist-to-hip ratio, grade point average and current smoking status.

RESULTS

Significant age and sex differences were identified in systolic blood pressure, diastolic blood pressure and all investigated independent variables. In a multivariate analysis, diastolic blood pressure in 10-year-old boys was directly and significantly related to total cholesterol and height, whereas it was inversely related to weight. At follow-up, in the multivariate model, only BMI was a significant predictor of diastolic blood pressure in boys. In girls at baseline in the multivariate regression analysis, the only significant predictor of diastolic blood pressure was total cholesterol. In 15-year-old girls, diastolic blood pressure was significantly and directly related to BMI and heart rate, whereas it was inversely related to weight. For both 10- and 15-year-old male and female participants, none of the variables by multivariate analysis were a significant predictor of systolic blood pressure.

CONCLUSIONS

Age, sex, heart rate, cholesterol and weight are the most important predictors of blood pressure in school children.