Humanized CYP2C19 transgenic mouse as an animal model of cerebellar ataxia

Background: Animal models are essential for understanding etiology and pathophysiology of movement disorders. Previously, we have found that mice transgenic for the human CYP2C19 gene, expressed in the liver and developing brain, exhibit altered neurodevelopment associated with impairments of their motor function and emotionality. Objectives: To characterize motoric phenotype of the CYP2C19 transgenic mice and validate its usefulness as an animal model of ataxia. Methods: The rotarod and beam-walking tests were utilized to quantify the functional alterations induced by motoric phenotype. Dopaminergic system was assessed by tyrosine hydroxylase immunohistochemistry and by chromatographic quantification of the whole-brain dopamine levels. Beam-walking test was also repeated after the treatment with the dopamine receptor antagonists, ecopipam and raclopride. The volumes of 20 brain regions in the CYP2C19 transgenic mice and controls were quantified by 9.4T gadolinium-enhanced postmortem structural neuroimaging. Results: CYP2C19 transgenic mice were found to exhibit abnormal, unilateral ataxia-like gait, clasping reflex and 5.6-fold more paw-slips using the beam-walking test (p<0.0001, n=89); the phenotype was more pronounced in younger animals. Hyperdopaminergism was observed in the CYP2C19 mice; however, the motoric impairment was not ameliorated by dopamine receptor antagonists and there was also no midbrain dopamine neuron loss in CYP2C19 mice. However, in these mice, cerebellar volume was drastically decreased (-11.8% [95%CI: -14.7, -9.0], q<0.0001, n=59), whereas a moderate decrease in hippocampal volume was observed (-4.2% [95%CI: -6.4%, -1.9%], q=0.015, n=59). Conclusions: Humanized CYP2C19 transgenic mice exhibit altered motoric function and functional motoric impairments; this phenotype is likely caused by an aberrant cerebellar development.

Efficacy and Safety of Adrenergic Alpha-1 Receptor Antagonists in Older Adults: A Systematic Review and Meta-analysis for the Development of Recommendations to Reduce Potentially Inappropriate Prescribing

BackgroundAdrenergic alpha-1 receptor antagonists (alpha-1 antagonists) are frequently used medications in the management of lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH) and in the management of therapy-resistant arterial hypertension, two conditions frequently found in older adults. This systematic review aims at presenting a complete overview of evidence over the benefits and risks of alpha-1 antagonist treatment in people ≥ 65 years, and at deriving recommendations for a safe application of alpha-1 antagonists in older adults from the evidence found.MethodsA comprehensive literature search was performed including multiple databases (Medline/Pubmed, Embase, the Cochrane Library) and using the PICOS framework to define search terms. The selection of the studies was done by two independent reviewers in a two-step approach, followed by a systematic data extraction. Quality appraisal was performed for each study included using standardised appraisal tools. The studies retrieved and additional literature were used for the development of recommendations, which were rated for strength and quality according to the GRADE methodology. ResultsFourteen studies were included: 3 meta-analyses, 6 randomised controlled trials and 5 observational trials. Doxazosin in the management of arterial hypertension was associated with a higher risk of cardiovascular disease, particularly heart failure, than chlorthalidone. Regarding treatment of LUTS suggestive of BPH, alpha-1 antagonists appeared to be effective in the relief of urinary symptoms and improvement of quality of life. They seemed to be less effective in preventing disease progression. Analyses of the risk profile indicated an increase in vasodilation related adverse events and sexual adverse events for some agents. One large observational study points at an increased risk of falls and fractures. The effects of long-term treatment remained unclear. All meta-analyses and 5 out of 6 interventional studies were downgraded in the quality appraisal. 4 out of 5 observational studies were of good quality.ConclusionsIt cannot be recommended to use doxazosin as first-line antihypertensive agent neither in older adults nor in younger patients. In the management of BPH alpha-1 antagonists promise to effectively relieve urinary symptoms with uncertainty regarding their efficacy in preventing long-term progression events.

Risk of Post-Myocardial Infarction Pneumonia with Proton Pump Inhibitors, H2 Receptor Antagonists and Mucoprotective Agents: A Retrospective Nationwide Cohort Study

Patients with myocardial infarction (MI) are at high risk of developing pneumonia. Proton pump inhibitors (PPI) and H2-receptor antagonists (H2RA) are commonly used acid-suppressive medications to the patients with MI for gastrointestinal (GI) protection, which may increase the risk for pneumonia. We evaluated whether PPI, H2RA, and mucoprotective agents without anti-acid properties increase the risk of post-MI pneumonia. We performed a retrospective cohort study based on the National Health Insurance Service—National Sample Cohort in Korea. The study included 3701 patients discharged with MI without prior history of pneumonia. During follow-up, treatments with PPI, H2RA, and mucoprotective agents were collected as time-dependent variables based on the prescription records. We performed multivariate time-dependent Cox regression analyses for the development of post-MI pneumonia. During the mean 4.85 ± 3.75 years follow-up, 999 participants developed pneumonia. In the multivariate analyses (adjusted hazard ratio; 95% confidence interval), the risk for pneumonia was significantly increased in treatment with PPI (2.25; 1.57–3.21) and H2RA (1.50; 1.16–1.93). Meanwhile, the risk for pneumonia was not increased in treatment with mucoprotective agents. When we evaluated GI bleeding event according to the medications as a secondary outcome analysis, mucoprotective agents were associated with increased GI bleeding risk, but PPI and H2RA were not. In the use of the GI medications in the treatment of patients with MI, the influence of these drugs on bleeding and pneumonia should be considered.