Statin myopathy: the fly in the ointment for the prevention of cardiovascular disease in the 21st century?

Introduction: Cardiovascular disease (CVD) remains the leading cause of death in industrialized nations. Despite clear evidence of CVD risk reduction with HMG-CoA reductase inhibitors (statins), the side effects of these medications, particularly myopathy, limit their effectiveness. Studies into the mechanisms, aetiology and management of statin myopathy are limited by lack of an internationally agreed clinical definition and tools for assessing outcomes. Currently there is a paucity of evidence to guide the management of patients affected by statin myopathy; with the exception of dose reduction, there is little evidence that other strategies can improve statin tolerance, and even less evidence to suggest these alternate dosing strategies reduce cardiovascular risk.

Areas covered: This review will cover current definitions, clinical presentations, risk factors, pathogenesis and management. PubMed was searched (English language, to 2014) for key articles pertaining to statin myopathy. This review then briefly describes our experience of managing this condition in a tertiary lipid disorders clinic, in the setting of limited guiding evidence.

Expert opinion: Knowledge gaps in the field of statin myopathy are identified and future research directions are suggested. We urge the need for international attention to address this important, but largely neglected clinical problem, that if unresolved will remain an impediment to the effective prevention and treatment of CVD.     

Exhaled nitric oxide in asthma in adults: the end is the beginning?

Approximately 20 years after the initial report of the measurement of exhaled nitric oxide (NO) in the exhaled air of humans, numerous publications have evaluated the possible applications of the fraction of exhaled NO (FeNO) in patients with asthma. The aim of the present review is to evaluate the technical issues and confounding factors related to FeNO measurements, as well as the role of FeNO in the diagnosis of asthma, the evaluation of asthmatic patients and the guidance of treatment. Several other issues, including the pursuit for "normal" and best personal values, the prediction of clinically relevant asthma outcomes and the identification of asthma phenotypes and future directions are discussed. FeNO represents the only exhaled biomarker that has reached clinical practice even in primary care settings and this review provides a critical view of the possible applications of this biomarker, both for the basic researcher and the clinician.     

Should the chickenpox vaccine be included in the National Immunization Schedule in India?

Varicella (chickenpox) is an acute, highly contagious viral disease with worldwide distribution. The highest prevalence occurs in the 4-10 year age group but tends to be more severe in adults. It may be fatal in neonates, immunocompromised persons, and normal adults, especially smokers. Varicella is usually a benign childhood disease, and rarely rated as an important public health problem, but this can be severe and even fatal in otherwise healthy children (< 1 out of every 10,000 cases). Chickenpox can cause pneumonia (23 out of every 10,000 cases), and is an important risk factor for developing severe invasive "strep" (group A streptococcal disease). Complications of varicella include bacterial infections (up to 5% of cases), decreased platelets, arthritis, hepatitis, pneumonia (more commonly in adults) or encephalitis (1 in 10,000 cases), which may cause a failure of muscular coordination, sometimes resulting in persistent sequelae or death. Varicella is the leading cause of vaccine-preventable death in children. Universal vaccination can cause a dramatic reduction in the incidence of varicella, associated complications, hospitalizations and fatality rates. In India, due to the high cost of the vaccine, it would be difficult to vaccinate a large percentage of the children. The government of India should consider the inclusion of varicella vaccine in the National Immunization Schedule with the help of International agencies.     

Importance of the Locus coeruleus and involvement of α-adrenergic receptors in the post-decapitation reflex in the rat

The latency, duration, hindlimb kick frequency, and total activity components of the post-decapitation reflex (PDR) were measured in the rat using a movement-sensitive transducer. Reduction of brain and spinal cord norepinephrine (NE) caused by neonatal administration of 6-hydroxydopamine (6-OHDA) or 5,7-dihydroxytryptamine, which also reduced brain serotonin, decreased all components of the PDR. Depletion of serotonin or dopamine alone reduced the vigor of the reflex, suggesting that these pathways can influence the PDR but are not essential for the response. Lesions of neurons in the Locus coeruleus, made electrolytically or with 6-OHDA, decreased the intensity of the PDR, with the 6-OHDA-induced lesion being more effective. Depletion of forebrain NE terminals with 6-OHDA did not alter the PDR, consistent with a critical involvement of spinal noradrenergic fibers. The PDR was also decreased by phentolamine and prazosin, but not by propanolol, suggesting an involvement of -adrenergic receptors in the response. This hypothesis was further supported by the finding that the efficacy of a variety of drugs (such as tricyclic antidepressants, phenothiazines, and antihypertensive compounds) for blocking the reflex was apparently related to their affinity for -adrenergic receptors. Thus, the PDR is dependent on noradrenergic fibers in the spinal cord and may provide a simple screen for drugs with suspected -adrenergic blocking properties or for agents that disrupt the function of central noradrenergic fibers.Bruce A. Pappas was a visiting Professor on sabbatical leave from the Department of Psychology, Carleton University, Ottawa, Canada K1S 5B6     

Electroretinographic and Ophthalmologic Examinations in the Yucatan Micropig and in the Göttingen Minipig

Abstract

External gross observations of the eye and its adnexae, ocular reflexes, anterior ocular segment biomicroscopic examinations, fundic examinations performed with an indirect ophthalmoscope, and/or electroretinographic investigations (ERG) were carried out on 112 7-12-month-old Yucatan micropigs, on 18 6-8-week-old, and 81 2-10-month old Gottingen minipigs to evaluate the incidence of observed ocular abnormalities and to compare the ERG waves. A statistical comparison was performed for these findings.

The most important ocular defects were classified as remnants of embryological vascular tissue. The other findings were considered either as embryonic remnants or of nondeterminate etiology. The most noteworthy findings were, in decreasing order of incidence, for Yucatan micropigs, 6-8 week-old and 2-10-monfh-old Gottingen minipigs, respectively, hyaloid artery remnants (82.1%, 83.3%, and 46.3%), pupillary     

An update on the advancements in the treatment of agitation in Alzheimer’s disease

Introduction: Neuropsychiatric symptoms (NPS) in Alzheimer’s disease (AD) are associated with significant negative outcomes for patients and their caregivers. Agitation, one of the most distressing NPS, lacks safe and effective long term interventions. Nonpharmacological interventions are suggested as first-line treatment, but aren’t effective for every patient, resulting in pharmacological interventions for some patients, consisting of off-label use of antipsychotics, sedative/hypnotics, anxiolytics, acetylcholinesterase inhibitors, memantine, and antidepressants; where efficacy doesn’t necessarily outweigh associated risks.

Areas covered: Gains in understanding neurobiological mechanisms underlying agitation have fueled several recent clinical trials. This article updates our review published in 2014. Comprehensive literature search for published articles from January 2014 to December 2016 evaluating pharmacologic interventions for agitation in AD was done. A review of several clinical trials was completed: dextromethorphan/quinidine, scyllo-inositol, brexpiprazole, prazosin, cannabinoids, citalopram, escitalopram, pimavanserin, ITI-007, ORM-12741 show promise in treating agitation.

Expert opinion: Neurobiological findings, innovative trials designs, statistical approaches, and preliminary paths for regulatory agency acceptance have re-ignited the area of pharmacological treatment of NPS. Though further research is needed to fully determine the safety, tolerability and efficacy of these treatments, the mission to find effective treatments for neuropsychiatric symptoms such as agitation in patients with dementia is well underway.     

Chemokine blockers--therapeutics in the making?

Chemokines are a family of small chemoattractant cytokines that have an important role in controlling leukocyte migration. The finding that some chemokines and their receptors are upregulated in both acute and chronic inflammatory diseases, and that they are key players in the development of AIDS, has provided the pharmaceutical industry with new targets for therapeutic intervention in these diseases. Although the chemokine system shows apparent redundancy in vitro, target validation is possible largely through expression studies in human disease tissues and the use of transgenic and knockout mice as disease models. Several approaches are being developed to block the effects of chemokines, including small-molecule antagonists of chemokine receptors, modified chemokines and antibodies directed against chemokine receptors. Here, we describe the rationale behind these different approaches, the pitfalls that have been encountered and future perspectives.     

Noradrenergic mechanism in the regulation of seizures in GEPR.

Genetically epilepsy prone rat (GEPR) is a model of generalized tonic/clonic epilepsy and a useful tool in the understanding of basic mechanisms of human epilepsy. GEPR is susceptible to audiogenic seizure, hyperthermia induced seizure,and has lower threshold for electrical and chemical stimuli. Several strains of GEPR, from GEPR-3 to GEPR-9, are available depending on the degree of the intensity of audiogenic seizure.     

Corticotropin-releasing factor antagonist attenuates the “anxiogenic-like” effect in the defensive burying paradigm but not in the elevated plus-maze following chronic cocaine in rats

Rationale: Chronic cocaine abuse is associated with the development of anxiogenic states in humans. Corticotropin-releasing factor (CRF) is an endogenous neurotropic factor well known to modulate stress responses. It has been postulated that CRF is involved in the neurobiological mechanisms underlying the anxiety and/or stress responses associated with removal of cocaine after chronic administration. Objective: The present study investigated the role of endogenous CRF in mediating the “anxiety-like” effect 48 h after the cessation of saline or chronic cocaine treatment in rats, using the defensive burying paradigm and the elevated plus-maze. Methods: Rats received daily injections of cocaine (20 mg/kg IP, for 14 consecutive days) or vehicle. Forty-eight hours after the last injection, animals were tested in the plus-maze and then in the defensive burying paradigm. In a second experiment, intracerebroventricular (ICV) cannulae were implanted at the lateral ventricle. Animals were allowed a 1-week period for recovery before starting the chronic drug treatment. The defensive burying testing took place 48 h after cessation of the treatment. The CRF antagonist [DPhe¹², Nle^21,38, C^αMe Leu³⁷] r/h CRF_(12–41), (also known as D-phe CRF_(12–41)) (0.04, 0.2 and 1.0 μg/5 μl) was injected 5 min before the 15-min testing. Results: An “anxiogenic-like” effect following chronic cocaine treatment was demonstrated with the defensive burying paradigm, but not with the elevated plus-maze. This “anxiety-like” response was attenuated by ICV pretreatment with the CRF antagonist D-Phe CRF_(12–41), with the highest dose of the CRF antagonist reversing the observed “anxiogenic-like” response. Conclusions: These data suggest that brain CRF may be substantially involved in the development of “anxiety-like” responses related to cocaine withdrawal and could be important for future drug dependence treatments. Received: 11 September 1997/Final version: 4 January 1999     

Evidence that LPS-reactive arthritis in rats depends on the glial activity and the fractalkine-TNF-α signaling in the spinal cord

It is known that primary afferent central terminal sensitization can influence peripheral inflammation, however, it remains to be understood whether spinal cord glia can also contribute to this process. Our aim was to investigate the effect of spinal cord glia inhibition on the pathogenesis of LPS-induced knee-joint monoarthritis in rats and also to investigate the role of fractalkine and TNF-α. LPS was injected into the knee-joint previously primed with carrageenan to cause articular incapacitation, edema, synovial leukocyte infiltration, and GFAP and CD11b/c spinal immunoreactivity (glia-IR) increase. Articular edema was more sensitive to the inhibition by intrathecal fluorocitrate and minocycline than nociception and synovial leukocyte content. The higher doses of both drugs were ineffective when given by intraperitoneal route. Corticosteroid synthesis inhibition by aminoglutethimide did not change the glia inhibitors effect. The inhibitory effect of the dorsal root potential inhibitor, furosemide, was not additive to that caused by fluorocitrate and minocycline. Intrathecal anti-fractalkine and anti-TNF-α inhibited edema, nociception, and synovial leukocytes, while fractalkine caused the opposite effects. The fractalkine effect was inhibited by fluorocitrate and anti-TNF-α. Finally, fluorocitrate, minocycline and anti-fractalkine attenuated, but fractalkine increased, GFAP and CD11b/c IR. The evidence reported herein supports the hypothesis that spinal fractalkine release is involved in glia activation, which via the spinal release of TNF-α, seems to be involved in the development and maintenance of this arthritis model. A possible modulation of the dorsal root reflexes is discussed. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.     

The significance ofβ-adrenoceptor down regulation in the desipramine action in the forced swimming test

Summary The present studies were undertaken to clarify whether central-adrenoceptor down regulation is responsible for the greater effect of chronic treatment with desipramine (DMI) compared with acute treatment in the forced swimming test in rats. Repetitive administration of DMI activated the rat behaviour pattern and consequently reduced the duration of immobility. The degree of activation depended on the length of treatment, i.e. no effect when given in a single dose, moderate effect when given subchronically (3 doses) and marked activation after chronic (31 doses) treatment. Chronic treatment with DMI also produced a decrease in³H-dihydroalprenolol (³H-DHA) binding site in the cerebral cortex. Acute stimulation of brain-adrenoceptors by intracerebroventricular (i.c.v.) isoprenaline significantly, though partially, attenuated the behavioural effect of chronic DMI by ₁-adrenoceptor-related mechanisms. Similarly, chronic i.c.v. co-administration of atenolol or practolol, ₁-adrenoceptor antagonists, together with DMI attenuated both-adrenoceptor down regulation and the behavioural activation by chronic DMI. On the other hand, chronic i.c.v administration of isoprenaline, supposedly leading to down regulation of-adrenoceptors, facilitated the activating behavioural effect of DMI, as a single dose became effective. Changes, however, in³H-DHA binding parameters in the cerebral cortex were not observed after chronic isoprenaline. These results suggest that down regulation of-adrenoceptors in brain is reponsible, at least in part, for the marked activatory effect of chronic DMI in the forced swimming test, possibly by reducing an inhibitory function of ₁-adrenoceptor mediated mechanisms.     

Antibiotheraphy in the 21st century, antibacterials for the second decade. Posibilities or realities in the future?

A review of some antibacterial products is done motivated by the serious situation arisen by the antimicrobial resistance in bacteria. The attention is focus on those drugs with suitable antimicrobial properties that have prospects to be commercialized in the next years because of they are undergoing a clinical development phase (I, II, III). The search for these antibacterial products has been done by an exhaustive study of conference proceedings and web pages of international congresses on chemotherapy, infectious diseases and new antimicrobial drugs. Some of the new antibacterial products acts on known targets, and they belong to already used families. Furthermore, the great majority acts against the gram-positive bacterium. There is also some limited-spectrum antimicrobial drug whose use would minimize the adverse biological effects.     

Secondary patents in the pharmaceutical industry: missing the wood for the trees?

Introduction: The critics of the Innovator pharmaceutical industry allege that secondary patents are trivial modifications over the primary patent, which extend its term and delay the entry of the generics in the market place. The protagonists regard secondary patents a result of continuous research and development (R&D), which help them introduce and protect new, differentiated products.

Areas covered: The areas covered are Product life cycle management (PLCM), Drug approval process, Orange book (OB) listed patents, US patent data.

Expert opinion: Our analysis of the patents and products of four innovators viz., AstraZeneca, Takeda, Eisai and Wyeth in the field of proton pump inhibitors (PPI’s) and Merck and Pfizer in the field of Statins shows that secondary patents help innovators sustain competition against other innovators in the specific product segment. The number of secondary patents listed in OB per NCE depends on the innovators interest in exploiting the NCE, the success of R & D effort and product lifecycle management strategy in the wake of market competition. Market entry decisions of innovators are strategic rather than a mere fallout of the secondary patents granted. Entry of another innovator is more unpredictable and hurts the first entrant more vis a vis the entry of generics who can enter the market when the patents protecting a product are no more enforceable, and hence more predictable. Generic entry in the field of PPI’s shows that the term of the primary patent is not extended by the secondary patents.     

Evidence supporting the existence of presynaptic α-adrenoceptors in the regulation of endogenous noradrenaline release upon hepatic sympathetic nerve stimulation in the dog liver in vivo

Summary The existence and functional signficance of presynaptic -adrenoceptors within the liver was investigated in anesthetized dogs. The stimulation-evoked endogenous catecholamine overflow was determined in hepatic venous blood upon hepatic nerve stimulation (12 V, 1–8 Hz, 1 min). Under resting conditions, average plasma catecholamine levels in hepatic venous and aortic blood were 0.064 ng/ml and 0.334 ng/ml, respectively. A frequency-dependent increase (P<0.001) was found in the hepatic venous catecholamine overflow, while aortic catechlamine levels did not change significantly at any stimulation frequency tested. The increases in catecholamine overflow were associated with decreases in hepatic arterial vascular conductance (35–66%, P<0.001) at all frequencies tested. Yohimbine (0.3 mg/kg, i. v.) potentiated the catecholamine overflow by 110–140% (P<0.05) upon stimulation at low frequencies (1–4 Hz). Clonidine (20g/kg, i. v.) inhibited the catecholamine overflow by 55–76% (P<0.05) at frequencies of 1 and 2 Hz, and reduced the hepatic arterial response by 46% (P<0.01) at 1 Hz. The pretreatment with yohimbine (0.1 mg/kg, i. v.) abolished the inhibitory effects of clonidine both on the catecholamine overflow and the hepatic arterial responses. The results support the existence of a negative feedback mechanism mediated by presynaptic -adrenoceptors in the local regulation of noradrenaline release from hepatic sympathetic fibers. A functional significance of this process was suggested by an improved correlation found in the presence of clonidine between the catecholamine overflow and the hepatic arterial vascular conductance.     

Reduction in phencyclidine induced sensorimotor gating deficits in the rat following increased system xc − activity in the medial prefrontal cortex

Rationale

Aspects of schizophrenia, including deficits in sensorimotor gating, have been linked to glutamate dysfunction and/or oxidative stress in the prefrontal cortex. System x_c ^?, a cystine–glutamate antiporter, is a poorly understood mechanism that contributes to both cellular antioxidant capacity and glutamate homeostasis.

Objectives

Our goal was to determine whether increased system x_c ^? activity within the prefrontal cortex would normalize a rodent measure of sensorimotor gating.

Methods

In situ hybridization was used to map messenger RNA (mRNA) expression of xCT, the active subunit of system x_c ^?, in the prefrontal cortex. Prepulse inhibition was used to measure sensorimotor gating; deficits in prepulse inhibition were produced using phencyclidine (0.3–3 mg/kg, sc). N-Acetylcysteine (10–100 μM) and the system x_c ^? inhibitor (S)-4-carboxyphenylglycine (CPG, 0.5 μM) were used to increase and decrease system x_c ^? activity, respectively. The uptake of ¹⁴C-cystine into tissue punches obtained from the prefrontal cortex was used to assay system x_c ^? activity.

Results

The expression of xCT mRNA in the prefrontal cortex was most prominent in a lateral band spanning primarily the prelimbic cortex. Although phencyclidine did not alter the uptake of ¹⁴C-cystine in prefrontal cortical tissue punches, intraprefrontal cortical infusion of N-acetylcysteine (10–100 μM) significantly reduced phencyclidine- (1.5 mg/kg, sc) induced deficits in prepulse inhibition. N-Acetylcysteine was without effect when coinfused with CPG (0.5 μM), indicating an involvement of system x_c ^?.

Conclusions

These results indicate that phencyclidine disrupts sensorimotor gating through system x_c ^? independent mechanisms, but that increasing cystine–glutamate exchange in the prefrontal cortex is sufficient to reduce behavioral deficits produced by phencyclidine.