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.

Human milk mycobiota composition: relationship with gestational age, delivery mode, and birth weight

Intestinal and human milk microbiota studies during infancy have shown variations according to geographical location, delivery mode, gestational age, and mother-related factors during pregnancy. In this study, we performed metagenomic mycobiota analyses of 44 transient and mature human milk among five different groups: mothers of normal spontaneous delivery-term (NS-T), caesarean delivery-term (CS-T), premature (PT), small for gestational age (SGA), and large for gestational age (LGA) infants. Fungi were detected in 80 out of the 88 samples. Regarding the number of observed fungal species, the NS-T group was more homogeneous (less variable) comparing the other groups (P<0.05). In the transient human milk samples, the most abundant species were Saccharomyces cerevisiae (33.3%) and Aspergillus glaucus (27.4%). While A. glaucus (33.7%) was second most abundant species in mature milk, S. cerevisiae disappeared (P<0.01) and Penicillium rubens became the most abundant species (35.5%) (P<0.05). Among the NS-T group, the most abundant species was Malassezia globosa in both transient and mature milk. In contrast, S. cerevisiae was the most abundant species in transient human milk (45.0%) in the CS-T group, but it disappeared in mature milk (P<0.01). In transient milk, M. globosa was only represented 6.0-9.0% of taxa in the PT, SGA, and LGA groups (P<0.05). In transient and mature milk in the PT, SGA and LGA groups, the most abundant species were A. glaucus and P. rubens. In mature milk samples, P. rubens is more abundant in CS-T group, PT group and LGA group, than the NS-T groups (P<0.05 for all). Although fungi constitute only a very small part of the human milk microbiome, we observed some changes that the human milk mycobiota composition varies in caesarean delivery, premature, SGA and LGA groups, comparing the normal spontaneous delivery, as well as differences between transient and mature human milk.

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.

Bronchial microbiome of severe COPD patients colonised by Pseudomonas aeruginosa

The bronchial microbiome in severe COPD during stability and exacerbation in patients chronically colonised by Pseudomonas aeruginosa (PA), has not been defined. Our objective was to determine the characteristics of the bronchial microbiome of severe COPD patients colonised and not colonised by P. aeruginosa and its changes during exacerbation. COPD patients with severe disease and frequent exacerbations were categorised according to chronic colonisation by P. aeruginosa. Sputum samples were obtained in stability and exacerbation, cultured, and analysed by 16S rRNA gene amplification and pyrosequencing. Sixteen patients were included, 5 of them showing chronic colonisation by P. aeruginosa. Pseudomonas genus had significantly higher relative abundance in stable colonised patients (p = 0.019), but no significant differences in biodiversity parameters were found between the two groups (Shannon, 3 (2-4) vs 3 (2-3), p = 0.699; Chao1, 124 (77-159) vs 140 (115-163), p = 0.364). In PA-colonised patients bronchial microbiome changed to a microbiome similar to non-PA-colonised patients during exacerbations. An increase in the relative abundance over 20 % during exacerbation was found for Streptococcus, Pseudomonas, Moraxella, Haemophilus, Neisseria, Achromobacter and Corynebacterium genera, which include recognised potentially pathogenic microorganisms, in 13 patients colonised and not colonised by P. aeruginosa with paired samples. These increases were not identified by culture in 5 out of 13 participants (38.5 %). Stable COPD patients with severe disease and PA-colonised showed a similar biodiversity to non-PA-colonised patients, with a higher relative abundance of Pseudomonas genus in bronchial secretions. Exacerbation in severe COPD patients showed the same microbial pattern, independently of previous colonisation by P. aeruginosa.