Prostaglandin signaling suppresses beneficial microglial function in Alzheimer’s disease models

Microglia, the innate immune cells of the CNS, perform critical inflammatory and noninflammatory functions that maintain normal neural function. For example, microglia clear misfolded proteins, elaborate trophic factors, and regulate and terminate toxic inflammation. In Alzheimer’s disease (AD), however, beneficial microglial functions become impaired, accelerating synaptic and neuronal loss. Better understanding of the molecular mechanisms that contribute to microglial dysfunction is an important objective for identifying potential strategies to delay progression to AD. The inflammatory cyclooxygenase/prostaglandin E2 (COX/PGE₂) pathway has been implicated in preclinical AD development, both in human epidemiology studies and in transgenic rodent models of AD. Here, we evaluated murine models that recapitulate microglial responses to Aβ peptides and determined that microglia-specific deletion of the gene encoding the PGE₂ receptor EP2 restores microglial chemotaxis and Aβ clearance, suppresses toxic inflammation, increases cytoprotective insulin-like growth factor 1 (IGF1) signaling, and prevents synaptic injury and memory deficits. Our findings indicate that EP2 signaling suppresses beneficial microglia functions that falter during AD development and suggest that inhibition of the COX/PGE₂/EP2 immune pathway has potential as a strategy to restore healthy microglial function and prevent progression to AD.     

Blood histamine levels in cotton-dust exposed workers in a textile mill of Ahmedabad

Blood histamine levels were measured by the bioassay of histamine (on an isolated strip of guinea pig ileum) in workers exposed to cotton dust in a textile mill in Ahmedabad. Byssinotic subjects showed very high levels of blood histamine as compared to nonbyssinotic and control subjects. The blood histamine levels were not well correlated to the dust concentrations or duration of exposure but rather to the day of the week (ie, first, second, third, etc., after weekend break) on which the samples were collected. The blood histamine levels were high on the first day of the work week, when byssinotics complained most of their symptoms.     

Vasopeptidase inhibition with omapatrilat improves cardiac geometry and survival in cardiomyopathic hamsters more than does ACE inhibition with captopril

Vasopeptidase inhibitors are single molecules that inhibit neutral endopeptidase (NEP) and angiotensin-converting enzyme (ACE) simultaneously. Omapatrilat, the first in this new class of cardiovascular agents, potentiates vasodilatory and cardioprotective peptides and represses angiotensin II. This study compared the effects of omapatrilat with those of a pure ACE inhibitor on cardiac geometry and survival in animals with heart failure. BIO TO-2 cardiomyopathic hamsters (CMHs) in the early stages of dilated heart failure were treated with vehicle or maximal ACE inhibitory doses of captopril (750 micromol/kg/day) or omapatrilat (200 micromol/kg/day). Prolonged vasopeptidase inhibition increased median survival time after the start of treatment by 99 and 31% compared with vehicle and captopril, respectively (median survival times: 146, 221, and 290 days with vehicle, captopril, and omapatrilat, respectively; p < 0.001 for all comparisons). In similar CMHs, captopril or omapatrilat administered for 2 months significantly (p < 0.05) decreased heart weight, pulmonary congestion (lung weight), and left ventricular (LV) chamber volume compared with vehicle. Omapatrilat significantly increased LV mass-to-volume ratio compared with vehicle and captopril. Omapatrilat, but not captopril, significantly increased urinary atrial natriuretic peptide excretion, indicating NEP inhibition. Thus vasopeptidase inhibition with omapatrilat was more effective than ACE inhibition with captopril in preventing changes in LV geometry and premature mortality in hamsters with dilated heart failure.     

Accelerating Regulated Bioanalysis for Biotherapeutics: Case Examples Using a Microfluidic Ligand Binding Assay Platform

The Gyrolab? xP is a microfluidic platform for conducting ligand binding assays (LBAs) and is recognized for its utility in discovery bioanalysis. However, few reports have focused on the technology for regulated bioanalysis. This technology has the advantage of low reagent consumption, low sample volume, and automated ligand binding methods. To improve bioanalysis testing timelines and increase the speed at which biotherapeutics are delivered to patients, we evaluated the technology for its potential to deliver high-quality data at reduced testing timelines for regulated bioanalysis. Six LBA methods were validated to support bioanalysis for GLP toxicokinetic or clinical pharmacokinetic studies. Validation, sample analysis, and method transfer are described. In total, approximately 4000 samples have been tested for regulated bioanalysis to support 6 GLP toxicology studies and approximately 1000 samples to support 2 clinical studies. Gyrolab? xP had high run pass rates (≥83%) and high incurred sample reanalysis (ISR) pass rates (>94%). The maximum total error observed across all QC levels for a given assay was <30% for all six LBAs. High instrument response precision (CV ≤5%) was observed across compact discs (CDs), and methods were validated to use a single standard curve across multiple CDs within a Gyrolab? xP run. Reduced bioanalysis timelines were achieved compared to standard manual plate-based methods, and methods were successfully transferred across testing labs, paving the way for this platform for use in late-stage clinical development.