Introduction: Rett syndrome (RTT) is an X-linked neurodevelopmental disorder and the second most common cause of mental retardation in females. Changes in microbiota composition, as observed in other neurological disorders such as autism, may account for several typical symptoms associated to RTT. Indeed, it is shown that a dysbiotic microbiota in gastrointestinal tract may affect the function of the nervous system. The main goal of this preliminary study was to characterize gut microbiota in RTT patients, and to compare it with a healthy control group of female of the same age. Materials and Methods: Eight RTT patients were enrolled at the Child Neuropsychiatry Department of San Paolo Hospital of Milan. Age and sex-matched healthy women (CTR), working at the University of Milan, were recruited. From all subjects we collected stool samples, anthropomet ricric data and dietary habits. Microbiota characterization was achieved by amplicon sequencing using 16S rRNA regions (V3-V4) genomic region with a Next Generation Sequencing approach on Illumina platform. Concentration of short chain fatty acids (SCFAs) was determined by gas-chromatography analysis. Results: Body mass index (BMI, kg/m2) was 17.4 ± 3.9 (mean ± SD) in RTT patients, and 20.9 ± 2.2 in control group (p = 0.0284). We did not observe differences in the mean value of Kcal/die (p = 0.43), but RTT diets were characterized by an increase in protein content (p = 0.029) and a lower intake of sugars (p = 0.0035). Microbiota analysis showed a significant lower alpha-diversity in RTT samples compared with control group (chao index and species richness p < 0.0001; shannon index p = 0.0015; and inverse simpson index p = 0.013). The predominant bacterial taxa in both groups were Firmicutes and Bacteroidetes. Although the Firmicutes/Bacteroidetes ratio was similar, at family level Bacteroidaceae were significantly higher in RTT samples (p = 0.0009), whereas Clostridiaceae, Ruminococcaceae and Christensenellaceae were strongly reduced. Desulfovibrio spp., as seen in autistic patients, was found increased in RTT patients (p = 0.0216). We did not find differences in butyrate and acetate concentration (p = 0.1144 and p = 0.6456, respectively) whereas fecal propionate was increased in RTT patients (p = 0.0248). Conclusions: We demonstrated in a small sample of patients that RTT gut microbiota is significantly different from the control group. Our hypothesis is that a dysbiotic gut in RTT patients could result in alterations of SCFAs that can worsen clinical symptoms by interacting at various levels (gut, brain, liver). Understanding critical changes could offer new tools for a diet intervention or probiotics supplementation to improve RTT associated symptoms and, ultimately, psycho-physical wellness.

Rett syndrome is associated with altered gut microbiota community / E. Borghi, F. Borgo, A. Riva, V. Truglia, M. Savini, M.C. Casiraghi, A. Vignoli. ((Intervento presentato al 44. convegno Congresso Nazionale della Societa' italiana di Microbiologia tenutosi a Pisa nel 2016.

Rett syndrome is associated with altered gut microbiota community

E. Borghi;F. Borgo;M.C. Casiraghi;A. Vignoli
2016-09-27

Abstract

Introduction: Rett syndrome (RTT) is an X-linked neurodevelopmental disorder and the second most common cause of mental retardation in females. Changes in microbiota composition, as observed in other neurological disorders such as autism, may account for several typical symptoms associated to RTT. Indeed, it is shown that a dysbiotic microbiota in gastrointestinal tract may affect the function of the nervous system. The main goal of this preliminary study was to characterize gut microbiota in RTT patients, and to compare it with a healthy control group of female of the same age. Materials and Methods: Eight RTT patients were enrolled at the Child Neuropsychiatry Department of San Paolo Hospital of Milan. Age and sex-matched healthy women (CTR), working at the University of Milan, were recruited. From all subjects we collected stool samples, anthropomet ricric data and dietary habits. Microbiota characterization was achieved by amplicon sequencing using 16S rRNA regions (V3-V4) genomic region with a Next Generation Sequencing approach on Illumina platform. Concentration of short chain fatty acids (SCFAs) was determined by gas-chromatography analysis. Results: Body mass index (BMI, kg/m2) was 17.4 ± 3.9 (mean ± SD) in RTT patients, and 20.9 ± 2.2 in control group (p = 0.0284). We did not observe differences in the mean value of Kcal/die (p = 0.43), but RTT diets were characterized by an increase in protein content (p = 0.029) and a lower intake of sugars (p = 0.0035). Microbiota analysis showed a significant lower alpha-diversity in RTT samples compared with control group (chao index and species richness p < 0.0001; shannon index p = 0.0015; and inverse simpson index p = 0.013). The predominant bacterial taxa in both groups were Firmicutes and Bacteroidetes. Although the Firmicutes/Bacteroidetes ratio was similar, at family level Bacteroidaceae were significantly higher in RTT samples (p = 0.0009), whereas Clostridiaceae, Ruminococcaceae and Christensenellaceae were strongly reduced. Desulfovibrio spp., as seen in autistic patients, was found increased in RTT patients (p = 0.0216). We did not find differences in butyrate and acetate concentration (p = 0.1144 and p = 0.6456, respectively) whereas fecal propionate was increased in RTT patients (p = 0.0248). Conclusions: We demonstrated in a small sample of patients that RTT gut microbiota is significantly different from the control group. Our hypothesis is that a dysbiotic gut in RTT patients could result in alterations of SCFAs that can worsen clinical symptoms by interacting at various levels (gut, brain, liver). Understanding critical changes could offer new tools for a diet intervention or probiotics supplementation to improve RTT associated symptoms and, ultimately, psycho-physical wellness.
Settore MED/07 - Microbiologia e Microbiologia Clinica
http://www.societasim.it/sim2016-info-generali.php
Rett syndrome is associated with altered gut microbiota community / E. Borghi, F. Borgo, A. Riva, V. Truglia, M. Savini, M.C. Casiraghi, A. Vignoli. ((Intervento presentato al 44. convegno Congresso Nazionale della Societa' italiana di Microbiologia tenutosi a Pisa nel 2016.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/466682
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