Neural integrity of the anterior insula is related to autonomic function in postmenopausal women with and without HIV

Abstract

Chronic exposure to HIV leads to cognitive derangement via neuro-inflammatory insult. It is hypothesized that HIV-infection and markers of neural and glial integrity of an important hub within the central autonomic network (i.e., anterior insula), will predict respiratory sinus arrhythmia (RSA) in post- menopausal women. Magnetic Resonance Spectroscopy (MRS) analysis was directed at a 15 mm3 region of the left anterior insula. MRS metabolite concentrations measured included N-acetylaspartate (NAA) and myo-Inositol (mI), biomarkers for glial and neuronal integrity. These levels were compared with expiratory- inspiratory (E/I) ratio in 13 post-menopausal women with and without HIV (mean age 55.62 years, SD = 5.04) during a slow-breathing test. A regression analysis indicated that HIV + status and increased levels of NAA within the insula explained 45% of the variance in the E/I ratio (R2 = 0.450, SE = 0.64 F(2,10) = 4.09, p = 0.05); in a second model HIV+ and mI explained 49% of the variance of lower E/I ratio (R2 = 0.494, SE = 0.60 F(2,11) = 4.385, p = 0.047). Higher levels of mI predicted a lower E/I ratios, beta = 0.019, SE = 0.008, p = 0.039, 95% CI [0.001,0.036]. Results indicate neural and glial integrity of the left anterior insula may predict vagal function in postmenopausal women, independent of HIV status.