Alternations in the Cardiovascular Autonomic Regulation and Growth Factors in Autism

Area of Science:

• Neuroscience
• Cardiovascular physiology
• Autism research

Background:

• Autism spectrum disorder (ASD) is a neurodevelopmental condition often accompanied by autonomic nervous system (ANS) dysregulation.
• Cardiovascular autonomic regulation is complex and involves interplay between heart rate variability (HRV) and blood pressure variability (BPV).

Purpose of the Study:

• To investigate complex cardiovascular autonomic regulation in children with ASD using HRV and systolic blood pressure variability (SBPV) analysis.
• To assess plasma levels of epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF) in children with ASD.
• To compare autonomic function and growth factor levels between children with ASD and neurotypical controls.

Main Methods:

• Utilized linear and non-linear analysis of HRV and SBPV at rest and during orthostatic stress in 25 boys with ASD and 25 age-matched controls.
• Measured RR intervals, spectral HRV (HF-HRV, LF-HRV), symbolic dynamics, spectral SBPV (LF-SBPV, HF-SBPV), blood pressure, and plasma EGF and VEGF levels.
• Employed continuous ECG and blood pressure monitoring during rest and orthostasis.

Main Results:

• Children with ASD exhibited significantly shortened RR intervals, lower HF-HRV, LF-SBPV, and HF-SBPV at rest compared to controls.
• These autonomic differences, specifically lower HF-HRV and LF-SBPV, persisted during orthostatic stress in the ASD group.
• Significantly lower plasma EGF levels were observed in children with ASD, though not correlated with autonomic parameters.

Conclusions:

• Autistic children demonstrate tachycardia, reduced cardiovagal activity, and impaired sympathetic vasomotor control at rest and during orthostasis.
• Complex heart rate dynamics were found to be similar between ASD and control groups.
• Reduced EGF levels in ASD warrant further investigation regarding their role in autonomic dysfunction and autism.