Association of Area Deprivation Index and hypertension, diabetes, dyslipidemia, and Obesity: A Cross-Sectional Study of the HABS-HD Cohort.

Objective: This study aims to investigate the association between neighborhood deprivation and the prevalence of major cardiovascular disease (CVD) risk factors (hypertension, diabetes, dyslipidemia, and obesity) in a Mexican American (MA) population compared to NonHispanic Whites (NHW). Method: A cross-sectional analysis was conducted to include 1,867 subjects (971 MA and 896 NHW). Participants underwent a clinical interview, neuropsychological exam battery, functional examination, MRI of the head, amyloid PET scan, and blood draw for clinical and biomarker analysis. We use the Area Deprivation Index (ADI) Model to assign an ADI score to participants based on their neighborhoods. Descriptive, Cochran-Armitage test for trend, and odds ratio statistical analysis were applied. Results: Our results suggest that NHW had higher odds of having HTN, DM, and obesity in the most deprived neighborhoods, while MA showed no increased odds. The study also found that neighborhood deprivation contributed to diabetes in both MA and NHW and was associated with obesity in NHW. Conclusions: These findings highlighted the importance of addressing both individual and societal factors in efforts to reduce cardiovascular risk. Future research should explore the relationship between socio-economic status and cardiovascular risk in more detail to inform the development of targeted interventions.

Vagus nerve stimulation does not improve recovery of forelimb motor or somatosensory function in a model of neuropathic pain.

Nerve injury affecting the upper limb is a leading cause of lifelong disability. Damage to the nerves in the arm often causes weakness and somatosensory dysfunction ranging from numbness to pain. Previous studies show that combining brief bursts of electrical vagus nerve stimulation (VNS) with motor or tactile rehabilitation can restore forelimb function after median and ulnar nerve injury, which causes hyposensitivity of the ventral forelimb. Here, we sought to determine whether this approach would be similarly effective in a model of radial nerve injury that produces allodynia in the ventral forelimb. To test this, rats underwent complete transection of the radial nerve proximal to the elbow followed by tubular repair. In the first experiment, beginning ten weeks after injury, rats received six weeks of tactile rehabilitation, consisting of mechanical stimulation of either the dorsal or ventral region of the forepaw in the injured limb, with or without concurrent VNS. In a second experiment, a separate cohort of rats underwent six weeks of forelimb motor rehabilitative training with or without paired VNS. Contrary to findings in previous models of hyposensitivity, VNS therapy fails to improve recovery of either somatosensory or motor function in the forelimb after radial nerve injury. These findings describe initial evidence that pain may limit the efficacy of VNS therapy and thus highlight a characteristic that should be considered in future studies that seek to develop this intervention.

High intensity VNS disrupts VNS-mediated plasticity in motor cortex.

Vagus nerve stimulation (VNS) paired with motor rehabilitation enhances recovery of function after neurological injury in rats and humans. This effect is ascribed to VNS-dependent facilitation of plasticity in motor networks. Previous studies document an inverted-U relationship between VNS intensity and cortical plasticity, such that moderate intensities increase plasticity, while low or high intensity VNS does not. We tested the interaction of moderate and high intensity VNS trains to probe the mechanisms that may underlie VNS-dependent plasticity. Rats performed a behavioral task where VNS was paired with jaw movement during chewing. For five days, subjects received 100 pairings of moderate intensity VNS (Standard VNS), 100 pairings alternating between moderate and high intensity VNS (Interleaved VNS), or 50 pairings of moderate intensity VNS (Short VNS) approximately every 8 s. After the final behavioral session, intracortical microstimulation (ICMS) was used to evaluate movement representations in motor cortex. 100 pairings of moderate intensity VNS enhanced motor cortex plasticity. Replacing half of moderate intensity stimulation with high intensity VNS blocked this enhancement of plasticity. Removing high intensity stimulation, leaving only 50 pairings of moderate intensity VNS, reinstated plasticity. These results demonstrate that there is a period for at least 8 s after high intensity stimulation in which moderate intensity VNS is not able to engage mechanisms required for synaptic reorganization. More importantly, this study demonstrates that changes in stimulation parameters are a critical determinant of the magnitude of plasticity and likely the efficacy of VNS-enhanced recovery.

The tactile experience paired with vagus nerve stimulation determines the degree of sensory recovery after chronic nerve damage.

Loss of sensory function is a common consequence of neurological injury. Recent clinical and preclinical evidence indicates vagus nerve stimulation (VNS) paired with tactile rehabilitation, consisting of delivery of a variety of mechanical stimuli to the hyposensitive skin surface, yields substantial and long-lasting recovery of somatosensory function after median and ulnar nerve transection and repair. Here, we tested the hypothesis that a specific component of the tactile rehabilitation paired with VNS is necessary for recovery of somatosensory function. In a second experiment in a separate cohort, we investigated whether VNS paired with tactile rehabilitation could improve skilled forelimb motor function. Elements of the study design, including planned sample size, assessments, and statistical comparisons, were preregistered prior to beginning data collection (https://osf.io/3tm8u/). Animals received a peripheral nerve injury (PNI) causing chronic sensory loss. Eight weeks after injury, animals were given a VNS implant followed by six weeks of tactile rehabilitation sessions consisting of repeated application of one of two distinct mechanical stimuli, a filament or a paintbrush, to the previously denervated forepaw. VNS paired with either filament indentation or brushing of the paw significantly improved recovery of forelimb withdrawal thresholds after PNI compared to tactile rehabilitation without VNS. The effect size was twice as large when VNS was paired with brushing compared to VNS paired with point indentation. An independent replication in a second cohort confirmed that VNS paired with brush restored forelimb withdrawal thresholds to normal. These rats displayed significant improvements in performance on a skilled forelimb task compared to rats that did not receive VNS. These findings support the utility of pairing VNS with tactile rehabilitation to improve recovery of somatosensory and motor function after neurological injury. Additionally, this study demonstrates that the sensory characteristics of the rehabilitation paired with VNS determine the degree of recovery.