211 ASSOCIATION OF PLASMA ANTIOXIDANTS AND COGNITIVE OUTCOMES IN NORTHERN IRISH MEN FROM PROSPECTIVE EPIDEMIOLOGICAL STUDY OF MYOCARDIAL INFARCTION (PRIME) STUDY

Background

Oxidative stress and chronic inflammation have been demonstrated to contribute to cognitive decline in older age and the development of neurodegenerative disorders. Antioxidants have been revealed to help mitigate the effects of the damage caused by oxidative stress and inflammation, but their relationship with cognitive decline is not yet fully understood. The aim of this study was to investigate the association between various plasma antioxidant levels and cognitive status in participants from the Prospective Epidemiological Study of Myocardial Infarction (PRIME) study.

Methods

10,600 men were recruited to the PRIME study between 1991-1993 and have been followed up across eleven time points. Baseline health and lifestyle characteristics were assessed, and plasma antioxidants were obtained and quantified. Baseline cognitive status was screened in 2000 using Mini-Mental State Examination (MMSE). Follow up assessment of cognitive status was performed in 2015 with MMSE and Addenbrooke’s Cognitive Examination-Revised (ACE-R) examinations.

Results

2,009 men underwent cognitive assessment in 2000 and 873 men in 2015. At both 2000 and 2015 with the use of the MMSE and ACE-R examinations to assess cognitive status, serum concentration of all the antioxidants except for gamma-tocopherol and lycopene were higher in the men with better cognitive performance at a significant level of p<0.05. Better cognitive performance was associated with more time spent in education and higher level of education achieved at a statistically significant level (p<0.01). Furthermore, those with cognitive impairment were more likely to be older. After adjustments for lifestyle variables with a linear regression model, the only significant variable associated with cognition was time spent in education (B = 0.521, p= 0.02).

Conclusion

The findings suggest that the concentration of plasma antioxidants is associated with cognitive status. Smoking and education, as well as other lifestyle factors were, demonstrated to have an impact on cognitive status.

Effects of IL-1β-Blocking Therapies in Type 2 Diabetes Mellitus: A Quantitative Systems Pharmacology Modeling Approach to Explore Underlying Mechanisms

Recent clinical studies suggest sustained treatment effects of interleukin-1β (IL-1β)–blocking therapies in type 2 diabetes mellitus. The underlying mechanisms of these effects, however, remain underexplored. Using a quantitative systems pharmacology modeling approach, we combined ex vivo data of IL-1β effects on β-cell function and turnover with a disease progression model of the long-term interactions between insulin, glucose, and β-cell mass in type 2 diabetes mellitus. We then simulated treatment effects of the IL-1 receptor antagonist anakinra. The result was a substantial and partly sustained symptomatic improvement in β-cell function, and hence also in HbA1C, fasting plasma glucose, and proinsulin–insulin ratio, and a small increase in β-cell mass. We propose that improved β-cell function, rather than mass, is likely to explain the main IL-1β–blocking effects seen in current clinical data, but that improved β-cell mass might result in disease-modifying effects not clearly distinguishable until >1 year after treatment.

Ablation of AMP-activated protein kinase alpha1 and alpha2 from mouse pancreatic beta cells and RIP2.Cre neurons suppresses insulin release in vivo

AIMS/HYPOTHESIS

AMP-activated protein kinase (AMPK) is an evolutionarily conserved enzyme and a target of glucose-lowering agents, including metformin. However, the precise role or roles of the enzyme in controlling insulin secretion remain uncertain.

METHODS

The catalytic alpha1 and alpha2 subunits of AMPK were ablated selectively in mouse pancreatic beta cells and hypothalamic neurons by breeding Ampkalpha1 [also known as Prkaa1]-knockout mice, bearing floxed Ampkalpha2 [also known as Prkaa2] alleles (Ampkalpha1 ( -/- ),alpha2( fl/fl ),), with mice expressing Cre recombinase under the rat insulin promoter (RIP2). RIP2 was used to express constitutively activated AMPK selectively in beta cells in transgenic mice. Food intake, body weight and urinary catecholamines were measured using metabolic cages. Glucose and insulin tolerance were determined after intraperitoneal injection. Beta cell mass and morphology were analysed by optical projection tomography and confocal immunofluorescence microscopy, respectively. Granule docking, insulin secretion, membrane potential and intracellular free Ca(2+) were measured with standard techniques.

RESULTS

Trigenic Ampkalpha1 ( -/- ),alpha2( fl/fl ) expressing Cre recombinase and lacking both AMPKalpha subunits in the beta cell, displayed normal body weight and increased insulin sensitivity, but were profoundly insulin-deficient. Secreted catecholamine levels were unchanged. Total beta cell mass was unaltered, while mean islet and beta cell volume were reduced. AMPK-deficient beta cells displayed normal glucose-induced changes in membrane potential and intracellular free Ca(2+), while granule docking and insulin secretion were enhanced. Conversely, betaAMPK transgenic mice were glucose-intolerant and displayed defective insulin secretion.

CONCLUSIONS/INTERPRETATION

Inhibition of AMPK activity within the beta cell is necessary, but not sufficient for stimulation of insulin secretion by glucose to occur. AMPK activation in extrapancreatic RIP2.Cre-expressing cells might also influence insulin secretion in vivo.