Association of Left Atrial Structure and Function With Cognitive Function in Adults With Metabolic Syndrome

Quercetin modulates expression of serum exosomal long noncoding RNA NEAT1 to regulate the miR-129-5p/BDNF axis and attenuate cognitive impairment in diabetic mice

AIMS

Cognitive impairment poses a considerable health challenge in the context of type 2 diabetes mellitus (T2DM), emphasizing the need for effective interventions. This study delves into the therapeutic efficacy of quercetin, a natural flavonoid, in mitigating cognitive impairment induced by T2DM in murine models.

MATERIALS AND METHODS

Serum exosome samples were obtained from both T2DM-related and healthy mice for transcriptome sequencing, enabling the identification of differentially expressed mRNAs and long noncoding RNAs (lncRNAs). Subsequent experiments were conducted to ascertain the binding affinity between mmu-miR-129-5p, NEAT1 and BDNF. The structural characteristics and dimensions of isolated exosomes were scrutinized, and the expression levels of exosome-associated proteins were quantified. Primary mouse hippocampal neurons were cultured for in vitro validation, assessing the expression of pertinent genes as well as neuronal vitality, proliferation, and apoptosis capabilities. For in vivo validation, a T2DM mouse model was established, and quercetin treatment was administered. Changes in various parameters, cognitive ability, and the expression of insulin-related proteins, along with pivotal signaling pathways, were monitored.

KEY FINDINGS

Analysis of serum exosomes from T2DM mice revealed dysregulation of NEAT1, mmu-miR-129-5p, and BDNF. In vitro investigations demonstrated that NEAT1 upregulated BDNF expression by inhibiting mmu-miR-129-5p. Overexpression of mmu-miR-129-5p or silencing NEAT1 resulted in the downregulation of insulin-related protein expression, enhanced apoptosis, and suppressed neuronal proliferation. In vivo studies validated that quercetin treatment significantly ameliorated T2DM-related cognitive impairment in mice.

SIGNIFICANCE

These findings suggest that quercetin holds promise in inhibiting hippocampal neuron apoptosis and improving T2DM-related cognitive impairment by modulating the NEAT1/miR-129-5p/BDNF pathway within serum exosomes.

Effect of an intensive lifestyle intervention on the structural and functional substrate for atrial fibrillation in people with metabolic syndrome

AIMS

To evaluate the effect of an intensive lifestyle intervention (ILI) on the structural and functional cardiac substrate of atrial fibrillation (AF) in overweight or obese people with metabolic syndrome (MetS).

METHODS

Participants of the PREDIMED-PLUS trial (n = 6874) were randomised 1:1 to an ILI program based on an energy-reduced Mediterranean diet, increased physical activity, and cognitive-behavioural weight management, or to a control intervention of low-intensity dietary advice. Left atrial (LA) strain, function, and volumes were evaluated by a core echocardiography lab in 534 participants at baseline, 3-year and 5-year follow-up. Mixed models were used to evaluate the effect of the ILI on LA structure and function.

RESULTS

In the subsample, baseline mean age was 65 years (SD 5 years), and 40% of the participants were women. Mean weight change after 5-years was -3.9 kg (SD 5.3 kg) in the ILI group and -0.3 kg (SD 5.1 kg) in the control group. Over the 5-year period, both groups experienced worsening of LA structure and function, with increases in LA volumes and stiffness index and decreases in LA longitudinal strain, LA function index and LA emptying fraction over time. Changes in the ILI and control group were not significantly different for any of the primary outcomes (LA emptying fraction: -0.95% (95%CI -0.93, -0.98) in control group, -0.97% (95%CI -0.94, -1.00) in ILI group, pbetween groups = 0.80; LA longitudinal strain: 0.82% (95%CI 0.79, 0.85) in control group, 0.85% (95%CI 0.82, 0.89) in ILI group, pbetween groups = 0.24) or any of the secondary outcomes.

CONCLUSIONS

In overweight or obese people with MetS, an ILI had no impact on the underlying structural and functional left atrial substrate measurements associated with AF risk.

Left Atrial Phasic Function via Cardiac Magnetic Resonance Imaging in Patients with Duchenne Muscular Dystrophy

Cardiac dysfunction is a leading cause of morbidity and mortality in Duchenne muscular dystrophy (DMD). Left atrial (LA) function is a poorly understood concept in this patient population, and research suggests underlying structural changes that could affect atrial function. Cardiac magnetic resonance (CMR) imaging may provide an important non-invasive approach to evaluating LA function. This study was a single center retrospective review of consecutive CMR studies over a 1 year period comparing LA phasic function within a cohort of DMD patients, and to those with structurally and functionally normal hearts. LA strain measurements including global reservoir, conduit, boost-pump strain, and LA volumes were obtained retrospectively. Spearman correlation analyses were performed on atrial strain measurements. 107 DMD and 79 normal CMR studies were included. The DMD cohort had worse systolic function (p < 0.001), smaller indexed max LA and left ventricular (LV) volumes (p < 0.001), and greater LA emptying fraction (p < 0.001). In the DMD cohort, emptying fraction decreased with advanced patient age (p < 0.001) and diminishing systolic function (p < 0.001). DMD patients with moderate or severe LV dysfunction demonstrated lower LA emptying fraction (p = 0.002), more impaired 2-chamber LA reservoir (p = 0.003), and LA pump (p = 0.006) and conduit strain (p = 0.018). DMD patients with preserved function have lower indexed LA volumes with higher LA emptying fractions than controls. Progression of disease and age is associated with decreased LA emptying fraction with early manifestations in reservoir and conduit strain. These findings suggest that strain markers of LA compliance and early left ventricular relaxation are associated with worsening cardiomyopathy in the DMD population.

Lifestyles, Left Atrial Structure and Function, and Cognitive Decline in Adults with Metabolic Syndrome

Evidence supports associations of lifestyle (including diet and physical activity) and weight with cognitive functioning, but the pathways responsible for these associations have not been fully elucidated. Because healthier lifestyles have been associated with better left atrial structure and function, which in turn is associated with better cognitive functioning, we tested the hypothesis that left atrial structure and function is a potential mediator of the association between lifestyle and cognition. We included 476 participants classed as overweight or obese with metabolic syndrome from three centers in Spain. These participants underwent lifestyle assessments and transthoracic echocardiography at baseline and repeated measurements of the Trail Making A test, a measure of executive function, taken at baseline and at the two-year follow-up. We conducted mediation analyses to test if measures of left atrial structure and function mediated associations between adherence to the Mediterranean diet scores, physical activity, and weight at baseline, as well as a two-year change in Trail Making A scores. The analysis did not find an association between these factors and Trail Making A scores, and no indirect effects appeared to be mediated by echocardiographic measurements. The modest sample size in this analysis is a limitation, and larger studies should be conducted to determine potential cardiovascular factors mediating the association between lifestyle and cognition.