Effects of a 6-Month Multifaceted Diet and Exercise Intervention on Cognition in Older Adults at Risk of Cognitive Decline: The PONDER Double-Blind, Placebo-Controlled Randomized Trial

Background: Multidomain interventions which incorporate exercise and dietary supplementation to target both cognitive and physical health domains may be an important approach to delay cognitive decline. Objective: The Protein Omega-3 aNd vitamin D Exercise Research (PONDER) study investigated the effects of a 6-month multifaceted intervention in community-dwelling older adults with subjective memory impairment on cognition (primary outcome), physical function, and body composition with a further 6-month follow up for cognition (secondary outcomes). Methods: Single-center, community-based, parallel-group, randomized, double-blind placebo-controlled trial involving a 6-month multifaceted intervention with a further follow-up at 12 months. A total of 147 participants [mean age 70.2 years (SD 6.1), 70% female] were randomized to a multimodal exercise program consisting of twice-weekly supervised resistance and aerobic training, combined with a daily omega-3 (900 mg EPA, 600 mg DHA), vitamin D (1000 IU) and protein (20 g) supplement (n = 73), or a control condition (n = 74) comprising stretching/flexibility sessions combined with a placebo. The primary outcome was a composite CogState measure and Trail-Making Test B-A. Results: There were no significant between-group differences in the change of cognition at 6 or 12 months or physical function outcomes at 6 months, but the intervention significantly improved total lean mass compared to controls [0.72 kg (95% CI 0.26–1.19), p = 0.001]. Conclusion: A multi-faceted intervention including an omega-3, vitamin D and protein-enriched supplement with twice-weekly exercise training did not provide any benefits to cognitive or physical function in older adults with subjective memory impairment, despite improvements in lean mass.

Omega-3 Long-Chain Polyunsaturated Fatty Acids: Are They Beneficial for Physical and Cognitive Functioning in Older Adults?

BACKGROUND

There is equivocal evidence about beneficial properties of omega-3 long-chain polyunsaturated fatty acids (ω-3 LCPUFA) for older adults.

OBJECTIVE

This study investigated the relationship between circulating ω-3 LCPUFA, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) levels and their corresponding dietary intakes with cognition and physical function in a cohort of community-dwelling older adults at risk of dementia.

METHODS

A cross-sectional analysis was conducted among 142 community-dwelling older adults (60-85 years) with subjective memory complaints. Erythrocyte fatty acids (ω-3 LCPUFA) and the omega-3 index were measured; dietary DHA and EPA were assessed with a LCPUFA specific questionnaire. Cognition was measured using the Cogstate computerised battery and Trail-making tests. Muscle strength was assessed by grip strength and physical function via the four-square step test, 30-second sit-to-stand, timed up-and-go test, and 4-m walk test. Multiple regression analysis was used to assess the relationship between erythrocyte ω-3 LCPUFA, dietary intake, cognitive and physical function.

RESULTS

Higher dietary DHA and EPA were associated with better global cognitive function (DHA: β=0.164, p=0.042; EPA: β=0.188, p=0.020). Higher dietary EPA was associated with better attention/psychomotor composite scores (β=0.196, p=0.024), mobility (four-square step test: β=-0.202, p=0.015) and gait speed (4m walk test: β=-0.200, p=0.017). No associations were found between erythrocyte ω-3 LCPUFA and cognitive or functional performance measures.

CONCLUSIONS

In community-dwelling older adults with subjective memory complaints, higher dietary ω-3 LCPUFA intake was associated with better cognitive and physical function, supporting the evidence that ω-3 fatty acids play a role in optimising physical and cognitive health during ageing.

Calmodulin Directly Interacts with the Cx43 Carboxyl-Terminus and Cytoplasmic Loop Containing Three ODDD-Linked Mutants (M147T, R148Q, and T154A) that Retain α-Helical Structure, but Exhibit Loss-of-Function and Cellular Trafficking Defects

The autosomal-dominant pleiotropic disorder called oculodentodigital dysplasia (ODDD) is caused by mutations in the gap junction protein Cx43. Of the 73 mutations identified to date, over one-third are localized in the cytoplasmic loop (Cx43CL) domain. Here, we determined the mechanism by which three ODDD mutations (M147T, R148Q, and T154A), all of which localize within the predicted 1-5-10 calmodulin-binding motif of the Cx43CL, manifest the disease. Nuclear magnetic resonance (NMR) and circular dichroism revealed that the three ODDD mutations had little-to-no effect on the ability of the Cx43CL to form α-helical structure as well as bind calmodulin. Combination of microscopy and a dye-transfer assay uncovered these mutations increased the intracellular level of Cx43 and those that trafficked to the plasma membrane did not form functional channels. NMR also identify that CaM can directly interact with the Cx43CT domain. The Cx43CT residues involved in the CaM interaction overlap with tyrosines phosphorylated by Pyk2 and Src. In vitro and in cyto data provide evidence that the importance of the CaM interaction with the Cx43CT may lie in restricting Pyk2 and Src phosphorylation, and their subsequent downstream effects.

Multifaceted intervention to enhance cognition in older people at risk of cognitive decline: study protocol for the Protein Omega-3 and Vitamin D Exercise Research (PONDER) study

INTRODUCTION

An increasing number of people are living with cognitive impairment and dementia. Current pharmacological therapies at best reduce Alzheimer's disease symptomatology but do not delay dementia onset in those at high risk. Structured exercise interventions can enhance cognition in older people; however, to produce long lasting, clinically relevant cognitive benefits, it is proposed that a multifaceted approach incorporating exercise with dietary supplements will address a wider range of mechanisms involved in cognitive decline. The Protein Omega-3 aNd vitamin D Exercise Research (PONDER) study aims to investigate the cognitive effects of a multimodal exercise programme combined with nutritional supplementation in older adults with subjective memory impairment (SMI).

METHODS AND ANALYSIS

The PONDER study is a single-centre, 12-month, community-based, parallel group, randomised, double-blind, placebo controlled trial involving a 6-month multifaceted intervention with a further 6-month follow-up. Participants will be 148 people from Melbourne, Australia, aged 60-85 years with SMI who will be randomised (1:1 ratio) to either a 6-month supervised multimodal exercise programme combined with omega-3 fatty acid, vitamin D and protein supplementation or a stretching/flexibility exercise programme combined with placebo supplements. The primary outcome is the change in cognition after 6 months as assessed by the Trail Making Test and global cognitive function assessed from the Cogstate Computerised battery. Secondary outcomes will include memory, working memory/learning and attention/psychomotor function, the Montreal Cognitive Assessment, mood, quality of life, muscle strength, physical function, body composition, cardiovascular health and sleep quality. Cognition at 12 months will represent a secondary outcome.

ETHICS AND DISSEMINATION

This study has been approved by the Deakin University Human Research Ethics Committee (project 2016-260). Informed consent will be obtained from all participants. The authors intend to submit the findings of the study to peer-reviewed journals or academic conferences to be published.

TRIAL REGISTRATION NUMBER

ACTRN12616001549415; Pre-results.

Characterization of the structure and intermolecular interactions between the connexin40 and connexin43 carboxyl-terminal and cytoplasmic loop domains

Gap junctions are intercellular channels that allow the passage of ions, small molecules, and second messengers that are essential for the coordination of cellular function. They are formed by two hemichannels, each constituted by the oligomerization of six connexins (Cx). Among the 21 different human Cx isoforms, studies have suggested that in the heart, Cx40 and Cx43 can oligomerize to form heteromeric hemichannels. The mechanism of heteromeric channel regulation has not been clearly defined. Tissue ischemia leads to intracellular acidification and closure of Cx43 and Cx40 homomeric channels. However, coexpression of Cx40 and Cx43 in Xenopus oocytes enhances the pH sensitivity of the channel. This phenomenon requires the carboxyl-terminal (CT) part of both connexins. In this study we used different biophysical methods to determine the structure of the Cx40CT and characterize the Cx40CT/Cx43CT interaction. Our results revealed that the Cx40CT is an intrinsically disordered protein similar to the Cx43CT and that the Cx40CT and Cx43CT can interact. Additionally, we have identified an interaction between the Cx40CT and the cytoplasmic loop of Cx40 as well as between the Cx40CT and the cytoplasmic loop of Cx43 (and vice versa). Our studies support the "particle-receptor" model for pH gating of Cx40 and Cx43 gap junction channels and suggest that interactions between cytoplasmic regulatory domains (both homo- and hetero-connexin) could be important for the regulation of heteromeric channels.

Preliminary studies of some physiological properties of Torula jeanselmei

The morphological characteristics of pathogenic and saprophytic strains of Torula jeanselmei (Fungi Imperfecti) are indistinguishable. Some basic physiological properties of T. jeanselmei were investigated in the hope of separating the human pathogenic strain from common saprophytes in a clinical laboratory. Nitrogen and carbon assimilation tests were not useful for distinguishing the pathogen, since all strains, pathogenic and saprophytic, were able to assimilate nitrogen from ammonium, nitrate, and nitrite sources, and all were able to utilize glucose, fructose, galactose, cellobiose, lactose, glycerol, and starch. It appeared that temperature range for growth might be useful in the identification of the pathogen. All pathogenic strains grew well at 37 C but poorly at 10 C; in contrast, all saprophytes could grow at 10 C but were unable to grow at 37 C (with two exceptions).