Obesity status and obesity-associated gut dysbiosis effects on hypothalamic structural covariance.

BACKGROUND: Functional connectivity alterations in the lateral and medial hypothalamic networks have been associated with the development and maintenance of obesity, but the possible impact on the structural properties of these networks remains largely unexplored. Also, obesity-related gut dysbiosis may delineate specific hypothalamic alterations within obese conditions. We aim to assess the effects of obesity, and obesity and gut-dysbiosis on the structural covariance differences in hypothalamic networks, executive functioning, and depressive symptoms. METHODS: Medial (MH) and lateral (LH) hypothalamic structural covariance alterations were identified in 57 subjects with obesity compared to 47 subjects without obesity. Gut dysbiosis in the subjects with obesity was defined by the presence of high (n = 28) and low (n = 29) values in a BMI-associated microbial signature, and posthoc comparisons between these groups were used as a proxy to explore the role of obesity-related gut dysbiosis on the hypothalamic measurements, executive function, and depressive symptoms. RESULTS: Structural covariance alterations between the MH and the striatum, lateral prefrontal, cingulate, insula, and temporal cortices are congruent with previously functional connectivity disruptions in obesity conditions. MH structural covariance decreases encompassed postcentral parietal cortices in the subjects with obesity and gut-dysbiosis, but increases with subcortical nuclei involved in the coding food-related hedonic information in the subjects with obesity without gut-dysbiosis. Alterations for the structural covariance of the LH in the subjects with obesity and gut-dysbiosis encompassed increases with frontolimbic networks, but decreases with the lateral orbitofrontal cortex in the subjects with obesity without gut-dysbiosis. Subjects with obesity and gut dysbiosis showed higher executive dysfunction and depressive symptoms. CONCLUSIONS: Obesity-related gut dysbiosis is linked to specific structural covariance alterations in hypothalamic networks relevant to the integration of somatic-visceral information, and emotion regulation.

Retrospective case-control study of viral pathogen screening in proliferative verrucous leukoplakia lesions.

OBJECTIVE: This study aimed to survey the presence of known oncoviruses in oral biopsies from patients diagnosed with the aetiologically undetermined proliferative verrucous leukoplakia and compare results to those from milder oral leukoplakia (OL) cases, oral squamous cell carcinoma, a common outcome of the lesions of interest, and healthy controls. DESIGN: Blind, retrospective, case-control study. SETTING: A stomatology unit in an academic Hospital and a Public Health laboratory. PARTICIPANTS: Forty patients were divided in four groups. Ten patients had been diagnosed with proliferative verrucous leukoplakia, 10 with OL and 10 with OSCC, and 10 were healthy subjects. MAIN OUTCOME MEASURES: The presence or absence of oncovirus DNA was assayed with the amplification of viral genetic markers using PCR and subsequent gel electrophoresis confirmation. Amplified fragments were sequenced and identified bioinformatically. RESULTS: No DNA from the herpesvirus, papillomavirus or polyomavirus species was detected in the samples. CONCLUSIONS: No association between proliferative verrucous leukoplakia and target viruses was detected. A higher throughput viral metagenomic approach may prove valuable for future analyses, as it would not be restricted to a priori knowledge of potential targets.