Probing the Role of Mitochondrial Oxidative Stress in Impaired Vascular Function Among Young Adults With Early Life Adversity

Adverse childhood experiences (ACEs) represent highly stressful events in the first 18 years of life that include abuse, neglect, and household and community-level dysfunction. ACEs promote cardiovascular morbidity and mortality in a graded, dose-dependent manner1 and are thus a significant, widespread determinant of cardiovascular disease (CVD). In agreement with preclinical evidence,2 we have established that young adults (18-29 y) with prior ACE exposure exhibit impaired vascular endothelial function (VEF)3 as evidenced by reduced flow mediated dilation even in the absence of clinical CVD risk factors. The vascular endothelium is a regulatory organ that plays a critical role in maintaining cardiovascular homeostasis, and our findings indicate that vascular endothelial dysfunction is one of the earliest identifiable pathophysiological mechanisms linking ACE exposure with future CVD. There remains a critical biomedical need to identify and understand the psychobiological mechanisms underlying ACEs-related vascular endothelial dysfunction to inform effective interventions to improve cardiovascular health in the millions of individuals affected by ACEs. The physiologic response to stress is coordinated across various physiological systems, all of which depend on energy supplied at the cellular level by mitochondria. Based on novel evidence across multiple physiological systems from our team, our overarching hypothesis is that dysregulation of mitochondrial function due to chronic stress burden - or mitochondrial allostatic load (MAL) - promotes dysregulation of the physiological stress response which is ultimately transduced to impairments in VEF in young adults with ACEs. Notably, our preliminary evidence also suggests that psychological resilience and executive functions such as cognitive reappraisal may moderate these relations, reducing MAL and preserving VEF in the face of substantial adversity. Here we propose the critical work necessary to understand these associations, which will directly inform identification of individuals who may be most vulnerable to stress-related cardiovascular risk and the development of interventions to promote cardiovascular-stress resilience.

In this study, we will use an acute dose of a mitochondrial targeted antioxidant supplement (MitoQ; or placebo) to experimentally interrogate the role of mitochondrial oxidative stress is associated with improvements in 1) vascular endothelial function and 2) cellular and integrated cardiovascular responses to a standardized laboratory based psychosocial stressor in young adults with Adverse Childhood Experiences.

Participants will report to the laboratory, provide a blood sample and have vascular endothelial function assessed using a specialized test known as flow mediated dilation, consume a single acute dose of MitoQ previously demonstrated to be effective and safe for acutely decreasing mitochondrial oxidative stress in humans OR placebo, and then have vascular endothelial function measured again. Next, participants will provide another blood sample before undergoing a standardized and commonly used laboratory psychosocial stress test known, before providing additional blood samples after test completion.

• Felitti VJ, Anda RF, Nordenberg D, Williamson DF, Spitz AM, Edwards V, Koss MP, et al. Relationship of childhood abuse and household dysfunction to many of the leading causes of death in adults: The adverse childhood experiences (ace) study. American Journal of Preventive Medicine. 1998;14:245-58. 2. Su S, Jimenez MP, Roberts CT, Loucks EB. The role of adverse childhood experiences in cardiovascular disease risk: A review with emphasis on plausible mechanisms. Curr Cardiol Rep. 2015;17:88. PMC4941633 3. Jenkins NDM, Rogers EM, Banks NF, Tomko PM, Sciarrillo CM, Emerson SR, Taylor A, et al. Childhood psychosocial stress is linked with impaired vascular endothelial function, lower sirt1, and oxidative stress in young adulthood. Am J Physiol Heart Circ Physiol. 2021;321:H532-H41. PMC8461842

Inclusion criteria

• 18-29 years
• ACE score >=4

Exclusion criteria

• Resting arterial blood pressure >140/90 mmHg
• BMI <=17 or >= 35
• Are on a weight-loss diet or involved in a formal weight-loss program or are not intentionally weight stable for 6 months (+/- 5 kg) prior to the study.
• Cardiovascular or metabolic prescription drug use
• Vasoactive antidepressant drug use (SSRIs and clonidine)
• Current heavy alcohol use, as defined as binge drinking on 5 or more days in the last month, or consuming more than 7 (women) or 14 (men) drinks per week in the last month (per NIAAA definition)
• Current or recent (within the last 6 mo.) illicit drug use disorder as indicated by a score of 3 or greater on the Drug Abuse Screening Test (DAST-10)
• Current tobacco or nicotine use
• Vaping
• Regular vigorous (>6 METs) aerobic exercise (>4 bouts/week, >30 min/bout)
• dietary supplementation with antioxidants or habitual use of NSAIDs
• Currently pregnant or breastfeeding