Interferons and cognition

Toll-like receptor 7-mediated enhancement of contextual fear memory in mice

Toll-like receptor (TLR) 7 recognizes viral single-stranded RNA and triggers production of the type I interferons (IFNs) IFN-α and IFN-β. Imiquimod, a synthetic TLR7 ligand, induces production of type I IFNs and is used clinically as an antiviral and antitumor drug. In the present study, we examined the effect of imiquimod on conditioned and innate fear behaviors in mice. Imiquimod was administered 2, 4, or 15 h before contextual fear conditioning. Imiquimod treatment 4 or 15 h before fear conditioning significantly enhanced context-dependent freezing behavior. This imiquimod-induced enhancement of fear-related behaviors was observed 120 h after fear conditioning. In contrast, imiquimod failed to enhance context-dependent freezing behavior in TLR7 knockout mice. Imiquimod had no significant effect on pain threshold or on innate fear-related behavior, as measured by the elevated plus-maze. The levels of type I IFN mRNA in the brain were significantly increased at 2 h after imiquimod treatment. Imiquimod also increased interleukin (IL)-1β mRNA expression in the brain at 4 h following administration, while mRNA expression of F4/80, a macrophage marker, was unaffected by imiquimod treatment. Our findings suggest that TLR7-mediated signaling enhances contextual fear memory in mice, possibly by inducing the expression of type I IFNs and IL-1β in the brain.

Cognitive dysfunction in multiple sclerosis

In Multiple Sclerosis (MS) prevalence studies of community and clinical samples, indicate that 45-60% of patients are cognitively impaired. These cognitive dysfunctions have been traditionally described as heterogeneous, but more recent studies suggest that there is a specific pattern of MS-related cognitive dysfunctions. With the advent of disease-modifying medications for MS and emphasis on early intervention and treatment, detection of cognitive impairment at its earliest stage becomes particularly important. In this review the authors address: the cognitive domains most commonly impaired in MS (memory, attention, executive functions, speed of information processing, and visual-spatial abilities); the pathophysiological mechanism implied in MS cognitive dysfunction and correlated brain MRI features; the importance of neuropsychological assessment of MS patients in different stages of the disease and the influence of its course on cognitive performance; the most used tests and batteries for neuropsychological assessment; therapeutic strategies to improve cognitive abilities.

Subcutaneous Interferon Beta-1a Has a Positive Effect on Cognitive Performance in Mildly Disabled Patients with Relapsing-Remitting Multiple Sclerosis: 2-Year Results from the COGIMUS Study

The effect of interferon (IFN) beta-1a (44 and 22 μg subcutaneously [sc] three times weekly [tiw]) on cognition in mildly disabled patients with relapsing-remitting multiple sclerosis (McDonald criteria; Expanded Disability Status Scale =4.0) was assessed by validated neuropsychological testing at baseline and at regular intervals for up to 2 years in this ongoing open-label, 3-year study. Year-2 data were available for 356 patients (22 μg, n = 175; 44μg, n = 181). The proportion of patients with impaired cognitive function was stable during the study: 21.4% at baseline and 21.6% at 2 years. At 2 years, the proportion of patients with =3 impaired cognitive tests was significantly lower in the 44 μg treatment group (17.0%) compared with the 22 μg group (26.5%; p = 0.034), although there was already a trend towards a higher proportion of patients with cognitive impairment in the 22 μg group at baseline. Factors associated with impairment in = three cognitive tests after 2 years were age (odds ratio [OR]: 1.05; 95% confidence interval [CI]: 1.00-1.09), verbal intelligence quotient (OR: 0.95; 95% CI: 0.92-0.98), and having = three impaired cognitive tests at baseline (OR: 11.60; 95% CI: 5.94-22.64). These interim results show that IFN beta-1a sc tiw may have beneficial effects on cognitive function as early as 2 years after treatment initiation, but the final 3-year data of the study are required to confirm these results.

When to initiate disease-modifying drugs for relapsing remitting multiple sclerosis in adults?

For patients with Relapsing Remitting Multiple Scierosis Beta Interfaerons and Glatiramer Acetate were the first to be licensed for treatment. This review deals with one major question: when to initiate therapy? Through exploring the unique characteristics of the disease and treatement we suggest an approach that should be helpful in the process of decision-making.

Plasma cytokine concentrations associated with HIV/hepatitis C coinfection are related to attention, executive and psychomotor functioning

Cytokine disturbances have been linked to brain dysfunction among HIV-infected people. Past studies have not simultaneously examined a large set of cytokine measures and their relationships to HIV-associated neurocognitive deficits. We hypothesized that performance on measures of attention and executive and psychomotor functions would be associated with plasma cytokine concentrations in HIV-infected individuals. Plasma samples drawn from 30 HIV-infected and 37 HIV seronegative individuals were analyzed via xMAP multiplexed bead array immunoassay to determine concentrations of 13 cytokines. Performance on Trail Making A/B, Stroop Test, Letter-Number Sequencing, Digit Symbol Coding, Symbol Search, and Grooved Pegboard tests was assessed. Statistical analyses were performed to examine group differences in cytokine concentrations, and associations between cytokine and HIV clinical variables and neurocognitive performance. Significant HIV effects were found on 7 of the 13 cytokines, primarily with respect to interleukins. HIV clinical factors (CD4 and HIV RNA levels, duration of illness, antiretroviral treatment) and hepatitis C status were associated with specific plasma cytokine concentrations. Neurocognitive measures were associated with cytokine concentrations, most consistently among the interleukins and IP-10. Generally, cytokine concentrations were among the strongest predictors of neurocognitive function relative to other clinical factors, which reinforces their potential importance in examining the neuropathological processes of HIV. The findings also point to the potential value of simultaneously examining a panel of biomarkers. The current results suggest that a complex relationship likely exists among cytokines [how?] and that these relationships are mediated not only by HIV infection but also by antiretroviral treatment and other comorbid conditions.

Cognitive function does not worsen during long-term low-dose peginterferon therapy in patients with chronic hepatitis C

OBJECTIVES

Neuropsychiatric toxicity is a common dose-limiting side effect of interferon therapy. The primary aim of this study was to determine whether patients receiving long-term low-dose peginterferon therapy had a higher incidence of cognitive side effects compared with untreated patients enrolled in the Hepatitis C Antiviral Long-Term treatment against Cirrhosis (HALT-C) Trial.

METHODS

A total of 129 patients with chronic hepatitis C and advanced fibrosis completed a battery of 10 neuropsychological tests and the Beck Depression Inventory at pretreatment baseline and at months 12, 24, 36, and 48 while receiving long-term peginterferonalpha2a (90 microg/week) or no therapy during the randomized phase of the HALT-C Trial. Cognitive impairment was defined as a global deficit score (GDS) > or = 1.0.

RESULTS

The mean age was 51.2 years, 67% were male, and 42% had cirrhosis. After accounting for baseline GDS scores, the mean GDS scores did not significantly change over time (P=0.46) nor with treatment group (P=0.49). Cognitive function was also not influenced by medication adherence in the 66 patients receiving maintenance peginterferon (P=0.14) after controlling for baseline GDS scores and time. Beck Depression scores did not significantly increase over time (P=0.60), nor did they vary by treatment group (P=0.74). Although 32% of patients experienced objective worsening of their liver disease during follow-up, the frequency and severity of cognitive impairment did not differ in those with and without disease progression (P=0.71).

CONCLUSIONS

Measures of cognitive function were neither influenced by low-dose peginterferon treatment nor with objective evidence of liver disease progression in patients with advanced chronic hepatitis C prospectively followed up for 3.5 years.

Effects of immunomodulatory treatment with subcutaneous interferon beta-1a oncognitive decline in mildly disabled patients with relapsing—remitting multiple sclerosis

The objective of this study was to assess the effects of subcutaneous (sc) interferon beta-1a (IFNβ-1a) on cognition in mildly disabled patients with relapsing—remitting multiple sclerosis (RRMS). Patients aged 18—50 years with RRMS (McDonald criteria; Expanded Disability Status Scale score ≤4.0) were assigned IFNβ therapy at the physician’s discretion and underwent standardized magnetic resonance imaging, neurological examination and neuropsychological testing at the baseline and regular intervals for up to three years.

This analysis included 459 patients who received sc IFNβ-1a (44 mcg: n = 236; 22 mcg: n = 223; three-year follow up was available for 318 patients). The hazard ratio for cognitive impairment over three years (44 mcg versus 22 mcg) was 0.68 (95% confidence interval [CI]: 0.480—0.972), suggesting a 32% lower risk with the higher dose treatment. At year 3, the proportion of patients who were cognitively impaired increased slightly from 23.5% at the baseline to 24.8% in the IFNβ-1a 22 mcg treatment group, but remained stable at 15.2% in the IFNβ-1a 44 mcg treatment group. The proportion of patients with cognitive impairment at year 3 was significantly higher in the 22 mcg group than in the 44 mcg group (P = 0.03), although a trend was also seen at the baseline (P = 0.058). Multivariate logistic regression (corrected for baseline cognitive deficits) indicated that treatment with the higher dose of IFNβ-1a was predictive of lower cognitive impairment at three years (odds ratio: 0.51, 95% CI: 0.26—0.99) compared with the lower dose of IFNβ-1a.

These findings suggest that sc IFNβ-1a may have dose-dependent cognitive benefits in mildly disabled patients with RRMS, and may support early initiation of high-dose IFNβ-1a treatment.

Cognitive dysfunction in MS: bridging the gap between neurocognitive deficits, neuropsychological batteries and MRI

Multiple sclerosis (MS) is an inflammatory and neurodegenerative disease of the CNS. Its sequelae include both physical and cognitive disability. Advances in neuropsychological testing and screening have led to increased recognition of cognitive impairment in MS; more than half of MS patients have been found to have some degree of cognitive impairment. Strong correlations have been found between neuropsychological testing, brain atrophy and other brain imaging techniques. These tools can aid in the comprehensive evaluation of MS patients. Genetic markers, such as ApoE and brain-derived neurotrophic factor polymorphisms, may also correlate with cognitive impairment in MS. This review details advances in recognizing and predicting cognitive dysfunction in MS. Increased understanding and better evaluation and monitoring of cognitive status in MS may improve the sensitivity of studies designed to test new disease-modifying therapies and interventions for cognitive impairment.

Cognitive impairment in multiple sclerosis

Cognitive dysfunctions are frequent symptoms of multiple sclerosis (MS) and occur in up to 65% of patients. Especially memory, attention, executive and visual constructive functions are impaired. These problems strongly affect patients' ability to work, social relationships, and quality of life. Symptoms of physical disabilities can arise independently. Cognitive dysfunctions are clear indicators of MS progression, because they represent highly complex functions that depend on the integrity of the neuronal networks. Once manifested after a relapse, they remain stable . Given a differentiating diagnosis, it is possible to treat these dysfunctions by cognitive training and with pharmaceutical drugs, for example by immunomodulating drugs. However, treatment options are limited at present. This report provides a detailed description of cognitive functions and performance in MS patients, their comorbidities such as fatigue and depression and therapeutic options.

Cognitive impairment in multiple sclerosis: evidence-based analysis and recommendations

Cognitive impairment is common in multiple sclerosis (MS), occurring at all stages of the disease, and can be a major source of vocational disability, social impairment, and impoverished quality of life. Dysfunction in free recall from long-term memory, speed of information processing, working memory, and abstract reasoning are frequently observed in MS. Despite weak correlation with disease duration and physical disability status, the degree of cognitive impairment in MS has been related to the extent of topographically specific neuronal tissue damage and loss. Additional clinical factors including disease course, fatigue, affective disturbance, and medication can impact on the degree of MS-related cognitive impairment. We suggest that the symbol digits modalities test, paced auditory serial addition task, the clock drawing test and the MS neuropsychological screening questionnaire be considered as valid and relevant screening tests for cognitive impairment in MS.

Prise en charge thérapeutique des troubles cognitifs dans la sclérose en plaques : données et perspectives

Taking in charge cognitive disorders is a new concept in the global care of MS patients. Cognitive disorders are observed in the all forms of the disease, sometimes early on in the evolution. These disorders can be evaluated in details even detected despite any complain in the patient. Because of the lack of clear demonstration that disease-modifying treatments could act on cognition, new specific therapeutic issues have emerged during last years. This article first discusses relationships between disease-modifying treatments and cognition for the different forms of the disease, then analyse the effects of symptomatic drug therapy especially the use of anticholinesterasics. In the last part of the article new issues about antagonists of excitatory amino-acids and individual or group cognitive training are discussed. Recent functional imaging data concerning cerebral adaptation and their modifications by drug or non-drug procedures in MS patients suggest interesting therapeutic development in a next future.