A neurobiological link between transportation noise exposure and metabolic disease in humans

BACKGROUND

Chronic transportation noise exposure associates with cardiovascular events through a link involving heightened stress-associated neurobiological activity (as amygdalar metabolic activity, AmygA) on ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT). Increased AmygA also associates with greater visceral adipose tissue (VAT) and type 2 diabetes mellitus (DM). While relationships between noise exposure and VAT and DM have been reported, the underlying mechanisms remain incompletely understood. We tested whether: (1) transportation noise exposure associates with greater (a) baseline and gains in VAT and (b) DM risk, and (2) heightened AmygA partially mediates the link between noise exposure and these metabolic diseases.

METHODS

VAT was measured in a retrospective cohort (N = 403) who underwent clinical ¹⁸F-FDG-PET/CT. AmygA was measured in those with brain imaging (N = 238). Follow-up VAT was remeasured on available imaging (N = 67). Among individuals (N = 224) without baseline DM, incident DM was adjudicated over 2 years from clinical records. Noise (24-h average) was modeled at each individual's home address. Linear regression, survival, and mediation analyses were employed.

RESULTS

Higher noise exposure (upper tertile vs. others) associated with greater: baseline VAT (standardized β [95% confidence interval (CI)]= 0.230 [0.021, 0.438], p = 0.031), gains in VAT (0.686 [0.185, 1.187], p = 0.008 adjusted for baseline VAT), and DM (hazard ratio [95% CI]=2.429 [1.031, 5.719], p = 0.042). The paths of: ↑noise exposure→↑AmygA→↑baseline VAT and ↑noise exposure→↑AmygA→↑subsequent DM were significant (p < 0.05).

CONCLUSIONS

Increased transportation noise exposure associates with greater VAT and DM. This relationship is partially mediated by stress-associated neurobiological activity. These findings suggest altered neurobiology contributes to noise exposure's link to metabolic diseases.

Stress-associated neurobiological activity is linked with acute plaque instability via enhanced macrophage activity: a prospective serial 18F-FDG-PET/CT imaging assessment

AIMS

Emotional stress is associated with future cardiovascular events. However, the mechanistic linkage of brain emotional neural activity with acute plaque instability is not fully elucidated. We aimed to prospectively estimate the relationship between brain amygdalar activity (AmygA), arterial inflammation (AI), and macrophage haematopoiesis (HEMA) in acute myocardial infarction (AMI) as compared with controls.

METHODS AND RESULTS

18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) imaging was performed within 45 days of the index episode in 62 patients (45 with AMI, mean 60.0 years, 84.4% male; 17 controls, mean 59.6 years, 76.4% male). In 10 patients of the AMI group, serial 18F-FDG-PET/CT imaging was performed after 6 months to estimate the temporal changes. The signals were compared using a customized 3D-rendered PET reconstruction. AmygA [target-to-background ratio (TBR), mean ± standard deviation: 0.65 ± 0.05 vs. 0.60 ± 0.05; P = 0.004], carotid AI (TBR: 2.04 ± 0.39 vs. 1.81 ± 0.25; P = 0.026), and HEMA (TBR: 2.60 ± 0.38 vs. 2.22 ± 0.28; P < 0.001) were significantly higher in AMI patients compared with controls. AmygA correlated significantly with those of the carotid artery (r = 0.350; P = 0.005), aorta (r = 0.471; P < 0.001), and bone marrow (r = 0.356; P = 0.005). Psychological stress scales (PHQ-9 and PSS-10) and AmygA assessed by PET/CT imaging correlated well (P < 0.001). Six-month after AMI, AmygA, carotid AI, and HEMA decreased to a level comparable with the controls.

CONCLUSION

AmygA, AI, and HEMA were concordantly enhanced in patients with AMI, showing concurrent dynamic changes over time. These results raise the possibility that stress-associated neurobiological activity is linked with acute plaque instability via augmented macrophage activity and could be a potential therapeutic target for plaque inflammation in AMI.

Stress-associated neurobiological activity associates with the risk for and timing of subsequent Takotsubo syndrome

AIMS

Activity in the amygdala, a brain centre involved in the perception of and response to stressors, associates with: (i) heightened sympathetic nervous system and inflammatory output and (ii) risk of cardiovascular disease. We hypothesized that the amygdalar activity (AmygA) ratio is heightened among individuals who develop Takotsubo syndrome (TTS), a heart failure syndrome often triggered by acute stress. We tested the hypotheses that (i) heightened AmygA precedes development of TTS and (ii) those with the highest AmygA develop the syndrome earliest.

METHODS AND RESULTS

Individuals (N=104, median age 67.5 years, 72% female, 86% with malignancy) who underwent clinical 18 F-FDG-PET/CT imaging were retrospectively identified: 41 who subsequently developed TTS and 63 matched controls (median follow-up 2.5 years after imaging). AmygA was measured using validated methods. Individuals with (vs. without) subsequent TTS had higher baseline AmygA (P=0.038) after adjusting for TTS risk factors. Further, AmygA associated with the risk for subsequent TTS after adjustment for risk factors [standardized hazard ratio (95% confidence interval): 1.643 (1.189, 2.270), P=0.003]. Among the subset of individuals who developed TTS, those with the highest AmygA (>mean + 1 SD) developed TTS ∼2 years earlier after imaging vs. those with lower AmygA (P=0.028).

CONCLUSION

Higher AmygA associates with an increased risk for TTS among a retrospective population with a high rate of malignancy. This heightened neurobiological activity is present years before the onset of TTS and may impact the timing of the syndrome. Accordingly, heightened stress-associated neural activity may represent a therapeutic target to reduce stress-related diseases, including TTS.

A neurobiological mechanism linking transportation noise to cardiovascular disease in humans

AIMS

Chronic noise exposure associates with increased cardiovascular disease (CVD) risk; however, the role of confounders and the underlying mechanism remain incompletely defined. The amygdala, a limbic centre involved in stress perception, participates in the response to noise. Higher amygdalar metabolic activity (AmygA) associates with increased CVD risk through a mechanism involving heightened arterial inflammation (ArtI). Accordingly, in this retrospective study, we tested whether greater noise exposure associates with higher: (i) AmygA, (ii) ArtI, and (iii) risk for major adverse cardiovascular disease events (MACE).

METHODS AND RESULTS

Adults (N = 498) without CVD or active cancer underwent clinical 18F-fluorodeoxyglucose positron emission tomography/computed tomography imaging. Amygdalar metabolic activity and ArtI were measured, and MACE within 5 years was adjudicated. Average 24-h transportation noise and potential confounders were estimated at each individual's home address. Over a median 4.06 years, 40 individuals experienced MACE. Higher noise exposure (per 5 dBA increase) predicted MACE [hazard ratio (95% confidence interval, CI) 1.341 (1.147-1.567), P < 0.001] and remained robust to multivariable adjustments. Higher noise exposure associated with increased AmygA [standardized β (95% CI) 0.112 (0.051-0.174), P < 0.001] and ArtI [0.045 (0.001-0.090), P = 0.047]. Mediation analysis suggested that higher noise exposure associates with MACE via a serial mechanism involving heightened AmygA and ArtI that accounts for 12-26% of this relationship.

CONCLUSION

Our findings suggest that noise exposure associates with MACE via a mechanism that begins with increased stress-associated limbic (amygdalar) activity and includes heightened arterial inflammation. This potential neurobiological mechanism linking noise to CVD merits further evaluation in a prospective population.

Relationship between chronic stress-related neural activity, physiological dysregulation and coronary artery disease in psoriasis: Findings from a longitudinal observational cohort study

BACKGROUND AND AIMS

Amygdalar 18F-fluorodeoxyglucose (FDG) uptake represents chronic stress-related neural activity and associates with coronary artery disease by coronary computed tomography angiography (CCTA). Allostatic load score is a multidimensional measure related to chronic physiological stress which incorporates cardiovascular, metabolic and inflammatory indices. To better understand the relationship between chronic stress-related neural activity, physiological dysregulation and coronary artery disease, we studied the association between amygdalar FDG uptake, allostatic load score and subclinical non-calcified coronary artery burden (NCB) in psoriasis.

METHODS

Consecutive psoriasis patients (n = 275 at baseline and n = 205 at one-year follow-up) underwent CCTA for assessment of NCB (QAngio, Medis). Amygdalar FDG uptake and allostatic load score were determined using established methods.

RESULTS

Psoriasis patients were middle-aged, predominantly male and white, with low cardiovascular risk by Framingham risk score and moderate-severe psoriasis severity. Allostatic load score associated with psoriasis severity (β = 0.17, p = 0.01), GlycA (a systemic marker of inflammation, β = 0.49, p < 0.001), amygdalar activity (β = 0.30, p < 0.001), and NCB (β = 0.39; p < 0.001). Moreover, NCB associated with amygdalar activity in participants with high allostatic load score (β = 0.27; p < 0.001) but not in those with low allostatic load score (β = 0.07; p = 0.34). Finally, in patients with an improvement in allostatic load score at one year, there was an 8% reduction in amygdalar FDG uptake (p < 0.001) and a 6% reduction in NCB (p = 0.02).

CONCLUSIONS

In psoriasis, allostatic load score represents physiological dysregulation and may capture pathways by which chronic stress-related neural activity associates with coronary artery disease, emphasizing the need to further study stress-induced physiological dysregulation in inflammatory disease states.

Psychosocial Stress and Cardiovascular Disease

PURPOSE OF REVIEW

This manuscript reviews the epidemiological data linking psychosocial stress to cardiovascular disease (CVD), describes recent advances in understanding the biological pathway between them, discusses potential therapies against stress-related CVD, and identifies future research directions.

RECENT FINDINGS

Metabolic activity of the amygdala (a neural center that is critically involved in the response to stress) can be measured on ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) yielding a neurobiological signal that independently predicts subsequent CVD events. Furthermore, a serial pathway from ↑amygdalar activity → ↑hematopoietic tissue activity → ↑arterial inflammation → ↑CVD events has been elucidated, providing new insights into the mechanism linking stress to CVD. Psychosocial stress and stress conditions are independently associated with CVD in a manner that depends on the degree and duration of stress as well as the individual response to a stressor. Nevertheless, the fundamental biology remains incompletely defined, and stress is often confounded by adverse health behaviors. Thus, most clinical guidelines do not yet recognize psychosocial stress as an independent CVD risk factor or advocate for its treatment in CVD prevention. Clarification of this neurobiological pathway provides a better understanding of the underlying pathophysiology and suggests opportunities to develop novel preventive strategies and therapies.