Dietary fish oil is antihypertrophic but does not enhance postischemic myocardial function in female mice.

Clinically and experimentally, a case for omega-3 polyunsaturated fatty acid (PUFA) cardioprotection in females has not been clearly established. The goal of this study was to investigate whether dietary omega-3 PUFA supplementation could provide ischemic protection in female mice with an underlying genetic predisposition to cardiac hypertrophy. Mature female transgenic mice (TG) with cardiac-specific overexpression of angiotensinogen that develop normotensive cardiac hypertrophy and littermate wild-type (WT) mice were fed a fish oil-derived diet (FO) or PUFA-matched control diet (CTR) for 4 wk. Myocardial membrane lipids, ex vivo cardiac performance (intraventricular balloon) after global no-flow ischemia and reperfusion (15/30 min), and reperfusion arrhythmia incidence were assessed. FO diet suppressed cardiac growth by 5% and 10% in WT and TG, respectively (P < 0.001). The extent of mechanical recovery [rate-pressure product (RPP) = beats/min x mmHg] of FO-fed WT and TG hearts was similar (50 +/- 7% vs. 45 +/- 12%, 30 min reperfusion), and this was not significantly different from CTR-fed WT or TG. To evaluate whether systemic estrogen was masking a protective effect of the FO diet, the responses of ovariectomized (OVX) WT and TG mice to FO dietary intervention were assessed. The extent of mechanical recovery of FO-fed OVX WT and TG (RPP, 50 +/- 4% vs. 64 +/- 8%) was not enhanced compared with CTR-fed mice (RPP, 60 +/- 11% vs. 80 +/- 8%, P = 0.335). Dietary FO did not suppress the incidence of reperfusion arrhythmias in WT or TG hearts (ovary-intact mice or OVX). Our findings indicate a lack of cardioprotective effect of dietary FO in females, determined by assessment of mechanical and arrhythmic activity postischemia in a murine ex vivo heart model

Preserving the demographic and genetic integrity of a single source population during multiple translocations

Globally, conservation translocations are common often using island, or‘virtual island’populations as a source site. We investigated demographic and genetic consequences of using a single source island population for multiple translocations. Our harvest selection protocol preserves the source population whilst providing individuals that are representative of the source population. Our study species, Tasmanian devils, are endangered due to an infectious cancer with an 80 % reduction in population size across their range. In 2012, an island population was established to protect the species. The island population was harvested three times with devils translocated to wild location across Tasmania (2016, N = 16; 2017, N = 33; 2018, N = 30). Efforts to harvest individuals demographically representative of the source population was achievable in 2017 and 2018, with a large male bias occurring in 2016 due to logistic constraints. Using internal relatedness (IR; proxy for hetero-zygosity), we showed that harvesting animals in equal-sized groups of high, medium and low IR, succeeded in maintaining genetic profiles of the source population over repeated harvests. There was little within-year variation in observed heterozygosity pre- and post-harvest compared to the harvest group, and only a small reduction (0.001) in heterozygosity across years. We used simulations to show that using a random selection would likely have eroded diversity relative to our structured approach (86.6% of iterations showed greater loss). Our method maintained a viable source population over multiple harvests, providing conservation managers with a tool for conserving single source populations used in threatened species translocatio

Knee osteoarthritis patients with severe nocturnal pain have altered proximal tibial subchondral bone mineral density

SummaryObjectiveOur objective was to investigate relationships between proximal tibial subchondral bone mineral density (BMD) and nocturnal pain in patients with knee osteoarthritis (OA).MethodsThe preoperative knee of 42 patients booked for knee arthroplasty was scanned using quantitative computed tomography (QCT). Pain was measured using the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and participants were categorized into three groups: ‘no pain’, ‘moderate pain’, and ‘severe pain’ while lying down at night. We used depth-specific image processing to assess tibial subchondral BMD at normalized depths of 0–2.5 mm, 2.5–5.0 mm and 5–10 mm relative to the subchondral surface. Regional analyses of each medial and lateral plateau included total BMD and maximum BMD within a 10 mm diameter core or ‘focal spot’. The association between WOMAC pain scores and BMD measurements was assessed using Spearman's rank correlation. Regional BMD was compared pairwise between pain and no pain groups using multivariate analysis of covariance using age, sex, and BMI as covariates and Bonferroni adjustment for multiple comparisons.ResultsLateral focal BMD at the 2.5–5 mm depth was related to nocturnal pain (ρ = 0.388, P = 0.011). The lateral focal BMD was 33% higher in participants with ‘severe pain’ than participants with ‘no pain’ at 2.5–5 mm depth (P = 0.028) and 32% higher at 5–10 mm depth (P = 0.049). There were no BMD differences at 0–2.5 mm from the subchondral surface.ConclusionThis study suggests that local subchondral bone density may have a role in elucidating OA-related pain pathogenesis