INSIG1 influences obesity-related hypertriglyceridemia in humans

In our analysis of a quantitative trait locus (QTL) for plasma triglyceride (TG) levels [logarithm of odds (LOD) = 3.7] on human chromosome 7q36, we examined 29 single nucleotide polymorphisms (SNPs) across INSIG1, a biological candidate gene in the region. Insulin-induced genes (INSIGs) are feedback mediators of cholesterol and fatty acid synthesis in animals, but their role in human lipid regulation is unclear. In our cohort, the INSIG1 promoter SNP rs2721 was associated with TG levels (P = 2 × 10−3 in 1,560 individuals of the original linkage cohort, P = 8 × 10−4 in 920 unrelated individuals of the replication cohort, combined P = 9.9 × 10−6). Individuals homozygous for the T allele had 9% higher TG levels and 2-fold lower expression of INSIG1 in surgical liver biopsy samples when compared with individuals homozygous for the G allele. Also, the T allele showed additional binding of nuclear proteins from HepG2 liver cells in gel shift assays. Finally, the variant rs7566605 in INSIG2, the only homolog of INSIG1, enhances the effect of rs2721 (P = 0.00117). The variant rs2721 alone explains 5.4% of the observed linkage in our cohort, suggesting that additional, yet-undiscovered genes and sequence variants in the QTL interval also contribute to alterations in TG levels in humans

Anatomy of avian rictal bristles in Caprimulgiformes reveals reduced tactile function in open-habitat, partially diurnal foraging species

Avian rictal bristles are present in many species of birds, especially in nocturnal species. Rictal bristles occur along the upper beak and are morphologically similar to mammalian whiskers. Mammalian whiskers are important tactile sensors, guiding locomotion, foraging and social interactions, and have a well‐characterised anatomy. However, it is not yet known whether avian rictal bristles have a sensory function, and their morphology, anatomy and function have also not been described in many species. Our study compares bristle morphology, follicle anatomy and their association with foraging traits, across 12 Caprimulgiform species. Rictal bristle morphology and follicle anatomy were diverse across the 12 species. Nine of the 12 species had mechanoreceptors around their bristle follicles; however, there was large variation in their musculature, mechanoreceptor numbers and bristle morphology. Overall, species with short, thin, branching bristles that lacked mechanoreceptors tended to forage pre‐dusk in open habitats, whereas species with mechanoreceptors around their bristle follicle tended to forage at night and in more closed habitats. We suggest that rictal bristles are likely to be tactile in many species and may aid in navigation, foraging and collision avoidance; however, identifying rictal bristle function is challenging and demands further investigation in many species

Novel genetic loci associated with hippocampal volume

The hippocampal formation is a brain structure integrally involved in episodic memory, spatial navigation, cognition and stress responsiveness. Structural abnormalities in hippocampal volume and shape are found in several common neuropsychiatric disorders. To identify the genetic underpinnings of hippocampal structure here we perform a genome-wide association study (GWAS) of 33,536 individuals and discover six independent loci significantly associated with hippocampal volume, four of them novel. Of the novel loci, three lie within genes (ASTN2, DPP4 and MAST4) and one is found 200 kb upstream of SHH. A hippocampal subfield analysis shows that a locus within the MSRB3 gene shows evidence of a localized effect along the dentate gyrus, subiculum, CA1 and fissure. Further, we show that genetic variants associated with decreased hippocampal volume are also associated with increased risk for Alzheimer's disease (rg =-0.155). Our findings suggest novel biological pathways through which human genetic variation influences hippocampal volume and risk for neuropsychiatric illness

Gait speed, cognition and falls in people living with mild-to-moderate Alzheimer disease: data from NILVAD

Contains fulltext : 220655.pdf (publisher's version ) (Open Access)BACKGROUND: Previous evidence suggests that slower gait speed is longitudinally associated with cognitive impairment, dementia and falls in older adults. Despite this, the longitudinal relationship between gait speed, cognition and falls in those with a diagnosis of dementia remains poorly explored. We sought to assess this longitudinal relationship in a cohort of older adults with mild to-moderate Alzheimer Disease (AD). METHODS: Analysis of data from NILVAD, an 18-month randomised-controlled trial of Nilvadipine in mild to moderate AD. We examined: (i) the cross-sectional (baseline) association between slow gait speed and cognitive function, (ii) the relationship between baseline slow gait speed and cognitive function at 18 months (Alzheimer Disease Assessment Scale, Cognitive Subsection: ADAS-Cog), (iii) the relationship between baseline cognitive function and incident slow gait speed at 18 months and finally (iv) the relationship of baseline slow gait speed and incident falls over the study period. RESULTS: Overall, one-tenth (10.03%, N = 37/369) of participants with mild-to-moderate AD met criteria for slow gait speed at baseline and a further 14.09% (N = 52/369) developed incident slow gait speed at 18 months. At baseline, there was a significant association between poorer cognition and slow gait speed (OR 1.05, 95% CI 1.01-1.09, p = 0.025). Whilst there was no association between baseline slow gait speed and change in ADAS-Cog score at 18 months, a greater cognitive severity at baseline predicted incident slow gait speed over 18 months (OR 1.04, 1.01-1.08, p = 0.011). Further, slow gait speed at baseline was associated with a significant risk of incident falls over the study period, which persisted after covariate adjustment (IRR 3.48, 2.05-5.92, p < 0.001). CONCLUSIONS: Poorer baseline cognition was associated with both baseline and incident slow gait speed. Slow gait speed was associated with a significantly increased risk of falls over the study period. Our study adds further evidence to the complex relationship between gait and cognition in this vulnerable group and highlights increased falls risk in older adults with AD and slow gait speed. TRIAL REGISTRATION: Secondary analysis of the NILVAD trial (Clincaltrials.gov NCT02017340; EudraCT number 2012-002764-27). First registered: 20/12/2013

Sedative Load in Community-Dwelling Older Adults with Mild-Moderate Alzheimer's Disease: Longitudinal Relationships with Adverse Events, Delirium and Falls.

Contains fulltext : 229319.pdf (Publisher’s version ) (Closed access

Cognitive Outcomes of Long-term Benzodiazepine and Related Drug (BDZR) Use in People Living With Mild to Moderate Alzheimer's Disease: Results From NILVAD

Contains fulltext : 218263.pdf (Publisher’s version ) (Closed access)OBJECTIVE: Benzodiazepines and related drugs (BDZRs) have been associated with an increased risk of Alzheimer's disease (AD) in later life. Despite this, it remains unclear whether ongoing BDZR use may further accelerate cognitive decline in those diagnosed with mild to moderate AD. DESIGN: This study was embedded within NILVAD, a randomized controlled trial of nilvadipine in mild to moderate AD. Cognition was measured at baseline and 18 months using the Alzheimer Disease Assessment Scale, Cognitive Subsection (ADAS-Cog). We assessed predictors of long-term BDZR use and analyzed the effect of ongoing BDZR use on ADAS-Cog scores at 18 months. Additionally, the impact of BDZR use on adverse events, incident delirium, and falls over 18-month follow-up was assessed adjusting for relevant covariates. SETTING AND PARTICIPANTS: 448 participants with mild to moderate AD recruited from 23 academic centers in 9 European countries. RESULTS: Overall, 14% (62/448) were prescribed an ongoing BDZR for the study duration. Increasing total number of (non-BDZR) medications was associated with a greater likelihood of BDZR prescription (odds ratio 1.16, 95% confidence interval 1.05-1.29). At 18 months, BDZR use was not associated with greater cognitive decline on the ADAS-Cog controlling for baseline ADAS-Cog scores, age, gender, study arm, and other clinical covariates (beta = 1.62, -1.34 to 4.56). However, ongoing BDZR use was associated with a greater likelihood of adverse events [incidence rate ratio (IRR) 1.19, 1.05-1.34], incident delirium (IRR 2.31, 1.45-3.68), and falls (IRR 1.66, 1.02-2.65) over 18 months that persisted after robust adjustment for covariates. CONCLUSIONS AND IMPLICATIONS: This study found no effect of ongoing BDZR use on ADAS-Cog scores in those with mild to moderate AD over 18 months. However, ongoing use of these medications was associated with an increased risk of adverse events, delirium, and falls. Thus, BDZR use should be avoided where possible and deprescribing interventions should be encouraged in older adults with AD