Simian immunodeficiency virus transiently increases brain temperature in rhesus monkeys: detection with magnetic resonance spectroscopy thermometry

Abstract

Purpose To evaluate brain temperature effects of early simian immunodeficiency virus (SIV) infection in rhesus macaques using proton magnetic resonance spectroscopy (MRS) thermometry (MRSt) and to determine whether temperature correlates with brain choline or myo‐inositol levels. Methods Brain temperature was retrospectively determined in serial MRS scans that had been acquired at baseline and at 2 and 4 weeks post‐SIV infection (wpi) in 16 monkeys by calculating the chemical shift difference between N‐acetylaspartate (NAA) and water peaks in sequentially acquired water‐suppressed and unsuppressed point‐resolved spectroscopy (PRESS) spectra. Frontal and parietal cortex, basal ganglia, and white matter spectra were analyzed. Results At 2 wpi, brain and rectal temperatures increased relative to baseline and normalized at 4 wpi. Brain temperatures correlated with choline levels in several brain areas, but not with myo‐inositol levels. Conclusion These data indicate that SIV transiently increases brain temperature soon after infection and that temperature is correlated with transient changes in choline levels. Given that choline levels are associated with brain inflammation in SIV‐infected monkeys, our findings suggest that the SIV‐induced temperature increase reflects brain inflammation. We conclude that MRSt may be informative in human immunodeficiency virus models and may be useful for assessing effects of treatments that reduce inflammation. This study also illustrates that existing MRS data sets containing unsuppressed water spectra can be used to measure tissue temperature, an important physiological parameter.

Contactless Thermometry by MRI and MRS: Advanced Methods for Thermotherapy and Biomaterials

“…The authors have experimentally shown that, with respiratory gating and motion compensation, but without bowel filling, the standard deviation may amount to about 10 C in the pancreas head, which would lead to problems in treatment evaluation and safety monitoring during thermal therapy. Filling the bowel through oral intake of 500 mL fluid increased the precision to 2 C. (Pineapple juice was chosen because of its high manganese content leading to short relaxation times, as had been demonstrated previously [Arthurs et al, 2014] (Mintzopoulos et al, 2019). Here, the chemical-shift difference between the methyl resonance of NAA and the water proton resonance was used to calculate absolute temperature for each voxel.…”

Chronic delta-9-tetrahydrocannabinol (THC) treatment counteracts SIV-induced modulation of proinflammatory microRNA cargo in basal ganglia-derived extracellular vesicles

“…Indeed, brain-derived EVs have been purified from cultured neurons, oligodendrocytes, microglia, astrocytes, and cerebrospinal fluid (CSF) [50][51][52]. However, there are no available studies describing the properties and functions of EVs from the basal ganglia (BG), a series of interconnected subcortical nuclei and a major target/ reservoir of HIV in the CNS [5,6]. BG dysfunction is a hallmark of HIV infection and cognitive impairment in PLWH with neuronal death in the BG [53].…”