Stephen Toovey

Maternal immune activation and abnormal brain development across CNS disorders

Epidemiological studies have shown a clear association between maternal infection and schizophrenia or autism in the progeny. Animal models have revealed maternal immune activation (mIA) to be a profound risk factor for neurochemical and behavioural abnormalities in the offspring. Microglial priming has been proposed as a major consequence of mIA, and represents a critical link in a causal chain that leads to the wide spectrum of neuronal dysfunctions and behavioural phenotypes observed in the juvenile, adult or aged offspring. Such diversity of phenotypic outcomes in the mIA model are mirrored by recent clinical evidence suggesting that infectious exposure during pregnancy is also associated with epilepsy and, to a lesser extent, cerebral palsy in children. Preclinical research also suggests that mIA might precipitate the development of Alzheimer and Parkinson diseases. Here, we summarize and critically review the emerging evidence that mIA is a shared environmental risk factor across CNS disorders that varies as a function of interactions between genetic and additional environmental factors. We also review ongoing clinical trials targeting immune pathways affected by mIA that may play a part in disease manifestation. In addition, future directions and outstanding questions are discussed, including potential symptomatic, disease-modifying and preventive treatment strategies.

Assessment of neuropsychiatric adverse events in influenza patients treated with oseltamivir: a comprehensive review.

After reports from Japan of neuropsychiatric adverse events (NPAEs) in children taking oseltamivir phosphate (hereafter referred to as oseltamivir [Tamiflu®; F. Hoffmann-La Roche Ltd, Basel, Switzerland]) during and after the 2004–5 influenza season, Roche explored possible reasons for the increase in reporting rate and presented regular updates to the US FDA and other regulatory authorities. This review summarizes the results of a comprehensive assessment of the company’s own preclinical and clinical studies, post-marketing spontaneous adverse event reporting, epidemiological investigations utilizing health claims and medical records databases and an extensive review of the literature, with the aim of answering the following questions: (i) what the types and rates of neuropsychiatric abnormalities reported in patients with influenza are, and whether these differ in patients who have received oseltamivir compared with those who have not; (ii) what levels of oseltamivir and its active metabolite, oseltamivir carboxylate are achieved in the CNS; (iii) whether oseltamivir and oseltamivircarboxylate have pharmacological activity in the CNS; and (iv) whether there are genetic differences between Japanese and Caucasian patients that result in different levels of oseltamivir and/or oseltamivir carboxylate in the CNS, differences in their metabolism or differences in their pharmacological activity in the CNS.In total, 3051 spontaneous reports of NPAEs were received by Roche, involving 2466 patients who received oseltamivir between 1999 and 15 September 2007; 2772 (90.9%) events originated from Japan, 190 (6.2%) from the US and 89 (2.9%) from other countries. During this period, oseltamivir was prescribed to around 48 million people worldwide. Crude NPAE reporting rates (per 1 000 000 prescriptions) in children (aged ≤16 years) and adults, respectively, were 99 and 28 events in Japan and 19 and 8 in the US. NPAEs were more commonly reported in children (2218 events in 1808 children aged >16 years vs 833 in 658 adults) and generally occurred within 48 hours of the onset of influenza illness and initiation of treatment. After categorizing the reported events according to International Classification of Diseases (9th edition) codes, abnormal behaviour (1160 events, 38.0%) and delusions/perceptual disturbances (661 events, 21.7%) were the largest categories of events, and delirium or delirium-like events (as defined by the American Psychiatric Association) were very common in most categories.No difference in NPAE reporting rates between oseltamivir and placebo was found in phase III treatment studies (0.5% vs 0.6%). Analyses of US healthcare claims databases showed the risk of NPAEs in oseltamivir-treated patients (n =159 386) was no higher than those not receiving antivirals (n = 159 386). Analysis of medical records in the UK General Practice Research Database showed that the adjusted relative risk of NPAEs in influenza patients was significantly higher (1.75-fold) than in the general population. Based on literature reports, NPAEs in Japanese and Taiwanese children with influenza have occurred before the initiation of oseltamivir treatment; events were also similar to those occurring after the initiation of oseltamivir therapy.No clinically relevant differences in plasma pharmacokinetics of oseltamivir and its active metabolite oseltamivir carboxylate were noted between Japanese and Caucasian adults or children. Penetration into the CNS of both oseltamivir and oseltamivir carboxylate was low in Japanese and Caucasian adults (cerebrospinal fluid/plasma maximum concentration and area under the plasma concentration-time curve ratios of approximately 0.03), and the capacity for converting oseltamivir to oseltamivir carboxylate in rat and human brains was low. In animal autoradiography and pharmacokinetic studies, brain: plasma radioactivity ratios were generally 20% or lower. Animal studies showed no specific CNS/behavioural effects after administration of doses corresponding to ≥100 times the clinical dose. Oseltamivir or oseltamivir carboxylate did not interact with human neuraminidases or with 155 known molecular targets in radioligand binding and functional assays. A review of the information published to date on functional variations of genes relevant to oseltamivir pharmacokinetics and pharmacodynamics and simulated gene knock-out scenarios did not identify any plausible genetic explanations for the observed NPAEs.The available data do not suggest that the incidence of NPAEs in influenza patients receiving oseltamivir is higher than in those who do not, and no mechanism by which oseltamivir or oseltamivir carboxylate could cause or worsen such events could be identified.

Travelers' Knowledge, Attitudes and Practices on the Prevention of Infectious Diseases: Results from a Study at Johannesburg International Airport

BACKGROUND Although Johannesburg International Airport (JIA) acts as a hub for travel into Africa, little was known of the knowledge, attitudes, and practices (KAP) with respect to infectious disease prevention of departing travelers. METHODS The study was conducted among departing passengers at JIA from August to October 2003. Travelers aged at least 18 years, resident in non-malarious developed countries and departing from JIA for risk destinations, were given either a malaria (Q-mal, n=219) or vaccine-preventable disease (Q-vac, n=200) questionnaire. European Travel Health Advisory Board traveler KAP questionnaires were used. RESULTS African destinations accounted for 99% of the total. Traveler mean age was 42 years, with 30% aged 50 years or above. Leisure (42%) and business (37%) were the commonest travel reasons; 8% of subjects were visiting friends or relatives. Forty-six per cent of travelers prepared for their trip at least 1 month in advance; 86% had sought pre-travel health advice, with travel clinics and the Internet being rated highest by travelers for quality of advice. World Health Organization immunization guidelines were followed poorly: only 37% and 27%, respectively, of travelers had demonstrable proof of protection against hepatitis A and B, with 40% of all Q-vac travelers unable to produce a vaccination certificate. Of travelers to yellow fever- endemic countries, 76% were able to produce a valid vaccination certificate; 22% of travelers to countries not endemic for yellow fever had nevertheless been specifically immunized against yellow fever for their journeys. Forty-nine per cent of Q-mal travelers carried either no or inappropriate antimalarials. CONCLUSIONS Considerable deficiencies in KAP were documented with regard to travel vaccinations and malaria protection in travelers departing JIA. Improved vaccine uptake and antimalarial prescribing are required for travelers to Africa.

Parkinson's disease or Parkinson symptoms following seasonal influenza.

Please cite this paper as: Toovey S et al. (2011) Parkinson’s disease or Parkinson symptoms following seasonal influenza. Influenza and Other Respiratory Viruses 5(5), 328–333.

Body mass index and the incidence of influenza-associated pneumonia in a UK primary care cohort

Please cite this paper as: Blumentals WA. et al. (2012) Body mass index and the incidence of influenza‐associated pneumonia in a UK primary care cohort. Influenza and Other Respiratory Viruses 6(1), 28–36.

Evaluation of the QT effect of a combination of piperaquine and a novel anti-malarial drug candidate OZ439, for the treatment of uncomplicated malaria

Aims The aim was to investigate the QT effect of a single dose combination regimen of piperaquine phosphate (PQP) and a novel aromatic trioxolane, OZ439, for malaria treatment. Methods Exposure–response (ER) analysis was performed on data from a placebo-controlled, single dose, study with OZ439 and PQP. Fifty-nine healthy subjects aged 18 to 55 years received OZ439 alone or placebo in a first period, followed by OZ439 plus PQP or matching placebos in period 2. OZ439 and PQP doses ranged from 100–800 mg and 160–1440 mg, respectively. Twelve-lead ECG tracings and PK samples were collected serially pre- and post-dosing. Results A significant relation between plasma concentrations and placebo-corrected change from baseline QTcF (ΔΔQTcF) was demonstrated for piperaquine, but not for OZ439, with a mean slope of 0.047 ms per ng ml−1 (90% CI 0.038, 0.057). Using an ER model that accounts for plasma concentrations of both piperaquine and OZ439, a largest mean QTcF effect of 14 ms (90% CI 10, 18 ms) and 18 ms (90% CI 14, 22 ms) was predicted at expected plasma concentrations of a single dose 800 mg OZ439 combined with PQP 960 mg (188 ng ml−1) and 1440 mg (281 ng ml−1), respectively, administered in the fasted state. Conclusions Piperaquine prolongs the QTc interval in a concentration-dependent way. A single dose regimen combining 800 mg OZ439 with 960 mg or 1440 mg PQP is expected to result in lower peak piperaquine plasma concentrations compared with available 3 day PQP-artemisinin combinations and can therefore be predicted to cause less QTc prolongation.

Post-Marketing Assessment of Neuropsychiatric Adverse Events in Influenza Patients Treated with Oseltamivir: An Updated Review

A 2008 review by our group concluded that the risk of neuropsychiatric adverse events (NPAEs) in influenza patients was not increased by oseltamivir exposure, and did not identify any mechanism by which oseltamivir or its metabolites could cause or worsen such events. The current article reviews new information on this topic. Between September 16, 2007 and May 15, 2010, 1,805 spontaneously-reported NPAEs were identified in 1,330 patients receiving oseltamivir: 767 (42.5%) from Japan, 296 (16.4%) from the USA, and 742 (41.1%) from other countries. NPAEs were more common in children: 1,072 (59.4%) events were in those aged ≤16 years. NPAEs often occurred within 48 h of treatment initiation (953 events; 52.8%). Nearly half of the events were serious in nature (838; 46.4%). The three largest categories of events were abnormal behavior (457 events, 25.3%), miscellaneous psychiatric events (370; 20.5%), and delusions/perceptual disturbances (316 events, 17.5%). A total of 1,545 events (85.6%) in eight different categories were considered to be delirium or delirium-like. Twenty-eight suicide-related events were reported. A US healthcare claims database analysis showed that the risk of NPAEs in 7,798 oseltamivir-treated patients was no higher than that in 10,411 patients not on antivirals, but a study on oseltamivir and abnormal behavior in Japan was less conclusive. NPAE frequency in oseltamivir-exposed Japanese and Taiwanese children with influenza was the same as in unexposed children. New analysis of the UK General Practice Research Database showed that the relative adjusted risk of NPAEs in influenza patients was 2.18-times higher than in the general population. Other epidemiology studies report frequent occurrence of encephalitis and similar disorders in influenza patients independently of oseltamivir exposure. The new data support the findings of the original assessment. Evidence suggests that influenza-related encephalopathies are caused by influenza-induced inflammatory responses, but more work is needed to confirm the underlying mechanisms.Supplementary material is available on SpringerLink.com.

Effect of Artemisinins and Amino Alcohol Partner Antimalarials on Mammalian Sarcoendoplasmic Reticulum Calcium Adenosine Triphosphatase Activity

The aim of this study was to assess the ability of currently deployed antimalarials to inhibit mammalian sarcoendoplasmic reticulum calcium adenosine triphosphatase (SERCA). Artemisinins exert their antiplasmodial action by inhibiting parasite PfATP6, a SERCA enzyme, and possess neurotoxic potential; mefloquine is neurotoxic and inhibits mammalian SERCA, an orthologue of PfATP6. SERCA in rabbit muscle was tested in vitro for inhibition by artemisinin and amino alcohol antimalarials. Significant inhibition of mammalian SERCA, as mean difference from uninhibited, control values was seen with both enantiomers of mefloquine: (+)-mefloquine (10 microM: -35.83, 95% CI -59.63 to -12.03; 50 microM: -54.06, 95% CI -77.86 to -30.26); (-)-mefloquine (10 microM: -24.35, 95% CI -41.56 to -7.15; 50 microM: -58.42, 95% CI -75.62 to -41.22); lumefantrine (1 microM: -25.46, 95% CI -45.82 to -5.10; 5 microM -34.83, 95% CI -60.08 to -9.58; 10 microM: -25.80, 95% CI -51.05 to -0.55); desbutyl-lumefantrine (5 microM: -50.16, 95% CI -84.24 to -16.08); dihydroartemisinin (1 microM: -39.25, 95% CI -63.74 to -14.76; 5 microM: -39.30, 95% CI -64.88 to -13.72). Dihydroartemisinin in higher concentrations (10 microM) stimulated SERCA activity: (+40.90, 95% CI 11.37 to 70.44). No statistically significant inhibition was seen with artemether at 1, 5 and 10 microM. Equimolar combinations of artemether and lumefantrine or of dihydroartemisinin and lumefantrine, when studied at concentrations that inhibit SERCA individually, failed to show any inhibition. Dihydroartemisinin, mefloquine, lumefantrine and desbutyl lumefantrine inhibit mammalian SERCA at periphysiological concentrations, although the neurotoxicity of mefloquine is not wholly attributable to this property. Candidate antimalarials should be screened pre-clinically for SERCA inhibition.

Malaria chemoprophylaxis regimens: A descriptive drug utilization study

BACKGROUND Mefloquine belongs to the priority chemoprophylaxis drugs for travelers to malaria endemic regions. We aimed to assess the prescribing patterns for mefloquine and other antimalarials. METHODS We conducted a descriptive drug utilization study using the U.K. Clinical Practice Research Datalink (CPRD). We assessed characteristics of individuals with a first-time antimalarial prescription for mefloquine, atovaquone/proguanil, chloroquine and/or proguanil, or doxycycline between 2001 and 2012. RESULTS Of 165,218 individuals with a first-time antimalarial prescription, 108,344 (65.6%), 25,294 (15.3%), 23,195 (14.0%), and 8385 (5.1%) were prescribed atovaquone/proguanil, mefloquine, doxycycline, and chloroquine and/or proguanil, respectively. Among mefloquine users, 7.5% had a history of a neuropsychiatric disorder (versus 12.6%-13.7% among other antimalarial users) and 0.04% had a history of severe liver disease (versus 0.04%-0.1% among other antimalarial users). A total of 19.4% mefloquine users were children younger than 12 years (versus 0.4%-15.8% among other antimalarials), and 1.3% pregnant or postpartum women (versus 0.4%-1.4% among users of other antimalarials). CONCLUSIONS The most frequently prescribed antimalarial chemoprophylaxis was atovaquone/proguanil. Mefloquine was occasionally prescribed for patients with comorbidities listed as contraindications, but most practitioners observed contraindications. Mefloquine was often prescribed for children and pregnant women.

The risk of new onset depression in association with influenza - a population-based observational study

IMPORTANCE Case-reports provided evidence that influenza infections, particularly severe episodes, may exert neuronal damage in the CNS and thereby increase the risk of depression. OBJECTIVE It was the aim of this study to analyse the association between influenza infections and the risk of developing incident depression. DESIGN We conducted a case-control analysis between 2000 and 2013 using the large UK-based primary care database Clinical Practice Research Datalink (CPRD). SETTING This database contains anonymous longitudinal data from primary care. At present, it contains over 100 million person-years of data from some 10 million active patients. PARTICIPANTS We encompassed 103307 patients below the age of 80 years with an incident major depression diagnosis between 2000 and 2013, and matched each case to one control patient on age, sex, general practice, number of medical encounters, and years of history in the CPRD prior to the index date. EXPOSURE Major depression diagnosis was identified by READ-codes based on ICD-10 codes (F32), with a minimum of three prescriptions for antidepressant drugs recorded after the diagnosis. MAIN OUTCOME We calculated relative risk estimates of developing depression in association with previous influenza infections, stratified by the number, timing and severity of such events, and we adjusted for a variety of comorbidities, smoking status, alcohol intake, body mass index, use of oral corticosteroids, and benzodiazepines. RESULTS Patients with a previous influenza infection had an increased risk of developing depression (OR 1.30, 95%CI 1.25-1.34) compared to patients with no history of influenza infections. A recent influenza infection recorded within 30-180 days prior to the index date yielded an adjusted 1.57 (95%CI 1.36-1.81), and an increasing number of previous influenza infections was associated with increasing odds ratios (⩾ 3 recorded influenza infections, adjusted OR 1.48, 95%CI 1.22-1.81). CONCLUSION This study suggests that influenza infections are associated with a moderately increased risk of developing depression.