Alteration of the sialylation pattern of the murine tooth germ after ethanol exposure

Prenatal, perinatal and postnatal events associated with hypomineralized second primary molar: a systematic review with meta-analysis

OBJECTIVE

The etiology of hypomineralized second primary molar (HSPM) appears to be multifactorial but remains uncertain. Thus, the objective was to systematically review studies that investigated adverse health conditions in the prenatal, perinatal and postnatal periods associated with HSPM.

MATERIAL AND METHODS

The search was carried out in five databases and in gray literature. The risk of bias of observational studies was analyzed according to the Newcastle-Ottawa scale.

RESULTS

A total of 1878 studies were identified. Fourteen were eligible, and seven were included in the meta-analysis. Maternal smoking (OR = 2.88; 95%CI: 1.62-5.15) and presence of maternal hypertension (OR = 2.91; 95%CI: 1.35-6.28) were significantly associated with higher odds of HSPM. In the perinatal period, factors associated with HSPM were low birth weight (OR = 1.50; 95%CI: 1.15-1.96), prematurity (OR = 1.93; 95%CI: 1.37-2.71), delivery complications (OR = 2.42; 95%CI: 1.52-3.83) and need for an incubator (OR = 1.65; 95%CI: 1.01-2.70). Not breastfeeding (OR = 1.26; 95%CI: 1.01-1.58), use of antibiotics by the child (OR = 1.24; 95%CI: 1.04-1.48), fever (OR = 1.37; 95%CI: 1.10-1.72) and asthma (OR = 1.91; 95%CI: 1.16-3.13) were the postnatal factors associated with HSPM.

CONCLUSION

Maternal smoking, maternal hypertension, low birth weight, prematurity, delivery complications, need for incubation, not breastfeeding, antibiotic use, fever and childhood asthma were associated with HSPM. Well-designed prospective cohort studies are needed. Clinical relevance Understanding the etiological factors can be guiding aspects for individual clinical approaches, as well as guiding the design of preventive interventions for HSPM.

Alcohol-induced suppression of KDM6B dysregulates the mineralization potential in dental pulp stem cells

Epigenetic changes, such as alteration of DNA methylation patterns, have been proposed as a molecular mechanism underlying the effect of alcohol on the maintenance of adult stem cells. We have performed genome-wide gene expression microarray and DNA methylome analysis to identify molecular alterations via DNA methylation changes associated with exposure of human dental pulp stem cells (DPSCs) to ethanol (EtOH). By combined analysis of the gene expression and DNA methylation, we have found a significant number of genes that are potentially regulated by EtOH-induced DNA methylation. As a focused approach, we have also performed a pathway-focused RT-PCR array analysis to examine potential molecular effects of EtOH on genes involved in epigenetic chromatin modification enzymes, fibroblastic markers, and stress and toxicity pathways in DPSCs. We have identified and verified that lysine specific demethylase 6B (KDM6B) was significantly dysregulated in DPSCs upon EtOH exposure. EtOH treatment during odontogenic/osteogenic differentiation of DPSCs suppressed the induction of KDM6B with alterations in the expression of differentiation markers. Knockdown of KDM6B resulted in a marked decrease in mineralization from implanted DPSCs in vivo. Furthermore, an ectopic expression of KDM6B in EtOH-treated DPSCs restored the expression of differentiation-related genes. Our study has demonstrated that EtOH-induced inhibition of KDM6B plays a role in the dysregulation of odontogenic/osteogenic differentiation in the DPSC model. This suggests a potential molecular mechanism for cellular insults of heavy alcohol consumption that can lead to decreased mineral deposition potentially associated with abnormalities in dental development and also osteopenia/osteoporosis, hallmark features of fetal alcohol spectrum disorders.

Pre- and postnatal determinants of deciduous molar hypomineralisation in 6-year-old children. The generation R study

BACKGROUND

Deciduous Molar Hypomineralisation (DMH) and Molar Incisor Hypomineralisation (MIH) are common developmental disturbances in pediatric dentistry. Their occurrence is related. The same determinants as suggested for MIH are expected for DMH, though somewhat earlier in life. Perinatal medical problems may influence the prevalence of DMH but this has not been studied sufficiently.

OBJECTIVE

This study aimed to identify possible determinants of DMH in a prospective cohort study among 6-year-old children.

STUDY DESIGN

This study was embedded in the Generation R Study, a population-based prospective cohort study from fetal life until young adulthood. The the data were used to identify the determinants of DMH. Clinical photographs of clean, moist teeth were taken with an intra-oral camera in 6690 children (mean age 6.2 years; 49.9% girls). Data on possible determinants that had occurred during pregnancy and/or the child's first year of life were on the basis of manual standardized measurements (like length and weight) and questionnaires. Multivariate analyse with backward and forward selection was performed.

RESULTS

A number of factors in the pre-, peri- and postnatal phase were found to be associated with DMH. After multivariate logistic regression analyses, Dutch ethnic background, low birth weight, maternal alcohol consumption during pregnancy, and fever episodes in the first year of the child's life were found to play a role in the development of DMH in 6-year-old children.

CONCLUSION

This study shows that Dutch ethnicity, low birth weight, alcohol consumption by the mother during pregnancy and any fever in the first year of the child's life are associated with DMH. Not only childhood factors but also prenatal lifestyle factors need to be taken into account when studying determinants for DMH.

Alteration of the sialylation pattern and memory deficits by injection of Aβ(25-35) into the hippocampus of rats

Sialic acid in glycoconjugates participates in important cellular functions associated with normal development, growth, and communication. Therefore we evaluated the sialylation pattern and memory deficits caused by the injection of Aβ((25-35)) into the hippocampus (Hp) of rats. The eight-arm maze spatial-learning and memory test indicated that the injection of Aβ((25-35)) into subfield CA1 of the Hp impaired both learning and memory. The sialylation pattern was examined using sialic acid-specific lectins. Our results showed that Maackia amurensis agglutinin (MAA, specific for Neu5Acα2,3Gal) showed reactivity in the CA1 and dentate gyrus (DG) subfields of the Hp mainly in the group injected with vehicle, whereas Macrobrachium rosenbergii lectin (MRL, specific for Neu5,9,7Ac) and Sambucus nigra agglutinin (SNA, specific for Neu5Acα2,6Gal-GalNAc) had increased reactivity in the CA1 and DG subfields of the Hp in the Aβ((25-35))-injected group. The staining pattern of the antibody specific for polysialic acid (a linear homopolymer of α-2,8-linked sialic acid) increased in the CA1 and DG subfields of the Hp of the Aβ((25-35)) group compared to the control group. Our results suggest that injection of Aβ((25-35)) causes impairment in spatial memory and alters the sialylation pattern in response to compensatory reorganization and-or sprouting of dendrites and axons of the surviving neurons.