Evaluation of effect of gestational diabetes mellitus on composition of the initial oral microbiota of neonates

Microbiome analysis of serum extracellular vesicles in gestational diabetes patients

AIM

Gestational Diabetes Mellitus (GDM) is among the most common complications during pregnancy, posing serious risks to both the patient's and offspring's health and well-being. Alterations in the maternal microbiome are closely associated with the pathogenesis of GDM, with Extracellular Vesicles (EVs) facilitating communication between microbiota and the host. However, little is known about the relationship between the microbial composition within EVs and the pathogenesis of GDM. Therefore, this study aims to characterize the microbiota within serum EVs of GDM Patients (GDM group) and to identify microbial communities that significantly differ from those in Women With Normal Pregnancies (NonGDM group).

METHODS

Blood samples were collected from both groups of patients, and EVs derived from serum were isolated via centrifugation. Identification and characterization of EVs were performed using transmission electron microscopy and nanoparticle flow cytometry. Microbiome analysis of serum EVs from both groups was conducted using 16S rRNA sequencing.

RESULTS

Results indicated altered diversity in microbial communities within serum EVs of GDM patients. Further analysis at the phylum, family, genus, and species levels revealed that Proteobacteria, Actinobacteria, Bacteroidetes, and Firmicutes were the dominant taxa in the EVs of both the NonGDM and GDM groups. Specifically, Actinobacteria and Firmicutes showed increased relative abundance in GDM group EVs compared to NonGDM, leading to a higher Firmicutes/Bacteroidetes ratio, while Proteobacteria and Bacteroidetes exhibited decreased relative abundance. Tax4Fun analysis revealed enrichment of microbial functions related to amino acid metabolism, carbohydrate metabolism, energy metabolism, and metabolism of cofactors and vitamins in both patient groups.

CONCLUSION

In conclusion, this study reveals a potential correlation between changes in the microbial composition and diversity of serum EVs and the onset and development of GDM. Furthermore, changes in the relative abundance of Actinobacteria, Proteobacteria, Bacteroidetes, and Firmicutes may play an important role in the pathogenesis of GDM.

Oral Microbiota of Infants in Maternal Gestational Diabetes: A Systematic Review

Gestational diabetes mellitus (GDM) affects approximately 5-20% of pregnant women and is associated with adverse pregnancy outcomes. This review aimed to assess whether the oral microbiota of infants and their mothers with GDM had a different composition from that found in unaffected women and offspring. PubMed, Embase, Scopus, and Google Scholar were searched in December 2023 after protocol registration in the International Prospective Register of Systematic Reviews (CRD42023406505). Risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal tools. Overall, 1113 articles were identified; after evaluating the full texts, 12 papers were included in the qualitative analysis. In six studies of the eight included, significant differences in microbiota between M-GDM and M-nGDM were found. In four studies, a depletion of Firmicutes and an enrichment of Proteobacteria was found in the microbiota of infants. Since all included studies were judged to have high risk of bias, a quantitative synthesis of the results was not carried out. In conclusion, although the oral microbiota of infants from mothers with GDM could be different from that of infants from mothers without GDM, there is insufficient evidence to clarify this aspect so far.

The Weissella and Periweissella genera: up-to-date taxonomy, ecology, safety, biotechnological, and probiotic potential

Bacteria belonging to the genera Weissella and Periweissella are lactic acid bacteria, which emerged in the last decades for their probiotic and biotechnological potential. In 2015, an article reviewing the scientific literature till that date on the taxonomy, ecology, and biotechnological potential of the Weissella genus was published. Since then, the number of studies on this genus has increased enormously, several novel species have been discovered, the taxonomy of the genus underwent changes and new insights into the safety, and biotechnological and probiotic potential of weissellas and periweissellas could be gained. Here, we provide an updated overview (from 2015 until today) of the taxonomy, ecology, safety, biotechnological, and probiotic potential of these lactic acid bacteria.

Influences of gestational diabetes mellitus on the oral microbiota in offspring from birth to 1 month old

BACKGROUND

Maternal gestational diabetes mellitus (GDM) had long-term influences on the health of their children. However, the influences of GDM on the oral microbiota, which was closely related to oral and systemic health in offspring, were less documented. The present study aimed to explore the oral microbiota of neonates born to mothers with GDM is differentially colonized compared with those born to mothers without GDM, and whether any such differences persist to 1 month of age.

METHODS

Oral samples were collected from children of mothers with (n = 20) and without GDM (n = 34) at birth and again at an average age of 1 month. The oral microbiota was characterized by 16S rRNA sequencing (V3-V4). Differences in diversity and composition according to maternal GDM status were assessed, and different metabolic functional pathways and microbial ecological networks were also analyzed.

RESULTS

Although no significant differences were observed in diversity metrics between GDM and non-GDM groups (P > 0.05), we found significant differences in the taxonomic composition of oral microbiota from phylum to genus level between the two groups, with the GDM group exhibiting less abundance of Veillonella in both "Day 1" (P < 0.001) and "Day 30" (P < 0.05) phases. Metabolic pathways analysis showed that 5-aminoimidazole ribonucleotide biosynthesis and inosine-5'-phosphate biosynthesis were enriched in GDM subjects in the "Day 30" phase. Moreover, ecological network analysis revealed apparent differences between GDM and control groups, with the non-GDM group containing more high-degree nodes and microbial interactions compared with the GDM group.

CONCLUSION

Maternal GDM was associated with an altered oral microbial composition in neonates, although the distinct difference between GDM and non-GDM groups diminished in infancy. The oral microbiota functions and ecological networks differed dramatically between the two groups, highlighting the importance of maternal GDM status on initial oral microbiota in offspring.

Microbiome alterations in women with gestational diabetes mellitus and their offspring: A systematic review

AIMS

Gestational diabetes mellitus (GDM) is a metabolic disorder that might predispose pregnant women to develop type 2 Diabetes Mellitus or lead to severe adverse outcomes in their offspring. One of the factors that have been thought to be involved in the pathology behind this disorder is the microbiome. In this systematic review, we comprehensively review the documents regarding the microbiota alterations in different tracts of pregnant women with GDM and their offspring.

METHODS

A comprehensive search was conducted in major databases including MEDLINE (PubMed), Scopus, and Web of sciences up to August 2021. Data on the demographics, methodology, and microbiome alterations were extracted and classified according to the type of microbiome in pregnant women with GDM and their offspring. The quality of studies was assessed using the Newcastle-Ottawa Scale (NOS).

RESULTS

In 49 articles which were retrieved, the findings were variable on the level of changes in alpha and beta diversity, enrichment or depletion in phyla, genera, species and OTUs, in each microbiome type. Although there were some inconsistencies among the results, a pattern of significant alterations was seen in the gut, oral, vaginal microbiome of women with GDM and gut, oral, and placental microbiome of their offspring.

CONCLUSION

Even though the alteration of the microbiome of the different tracts was seen in the cases of GDM, the inconsistency among the studies prevents us from identifying unique pattern. However, the results seem promising and further studies that overcome the confounding factors related to the demographics and methodology are needed.

Periodontitis and Gestational Diabetes Mellitus: A Potential Inflammatory Vicious Cycle

Periodontitis is a chronic inflammatory immune disease associated with a dysbiotic state, influenced by keystone bacterial species responsible for disrupting the periodontal tissue homeostasis. Furthermore, the severity of periodontitis is determined by the interaction between the immune cell response in front of periodontitis-associated species, which leads to the destruction of supporting periodontal tissues and tooth loss in a susceptible host. The persistent bacterial challenge induces modifications in the permeability and ulceration of the sulcular epithelium, which facilitates the systemic translocation of periodontitis-associated bacteria into distant tissues and organs. This stimulates the secretion of pro-inflammatory molecules and a chronic activation of immune cells, contributing to a systemic pro-inflammatory status that has been linked with a higher risk of several systemic diseases, such as type 2 diabetes mellitus (T2DM) and gestational diabetes mellitus (GDM). Although periodontitis and GDM share the common feature of systemic inflammation, the molecular mechanistic link of this association has not been completely clarified. This review aims to examine the potential biological mechanisms involved in the association between periodontitis and GDM, highlighting the contribution of both diseases to systemic inflammation and the role of new molecular participants, such as extracellular vesicles and non-coding RNAs, which could act as novel molecular intercellular linkers between periodontal and placental tissues.