Pathogenesis of Congenital Malformations: Possible Role of Oxidative Stress

Effects of effluents from the Villa Victoria Reservoir (Mexico) on the development of Danio rerio at early life stages through apoptotic response and oxidative-induced state

As one of Mexico's most crucial water storage facilities, the Villa Victoria Reservoir (VVR) supplies water to over six million people residing in the Mexico City Metropolitan Area. In recent years, this water resource has been subjected to significant risks due to several factors, including human population growth, alterations in global climate patterns, excessive resource utilization, and insufficient protective regulations, thereby endangering not only the biocenosis itself, but also the water supply for numerous inhabitants. This study aimed to evaluate the current state of the reservoir through the determination of conventional and emerging pollutants present in the sampling points, as well as embryotoxicity and oxidative damage in Danio rerio embryos exposed to effluents from the VVR. Embryotoxicity was quantified using the General Morphology Score (GMS) and teratogenic index, whereas oxidative damage was assessed based on lipid peroxidation, hydroperoxide content, oxidized proteins, antioxidant enzyme activity, and gene expression. These results revealed the presence of heavy metals, diverse pharmaceutical compounds, and pesticides. In addition, elevated lipid, hydroperoxide, and protein oxidation accompanied by alterations in superoxide dismutase (SOD) and catalase (CAT) enzymatic activity were observed during exposure. GMS resulted in impaired embryo development and teratogenic effects, including pericardial, axial, and skeletal edema. Furthermore, the upregulation of genes associated with apoptotic processes and antioxidant defense reflects a comprehensive response to oxidative stress. The study concluded that pollutants in VVR water induced oxidative damage, modified antioxidant activity, elicited embryotoxicity, and upregulated oxidative damage-related genes. The findings underscore the necessity of undertaking restoration efforts for water sources, as pollution can potentially endanger aquatic organisms and human well-being.

Periconceptional polycyclic aromatic hydrocarbon levels in maternal hair and fetal risk for congenital heart defects

BACKGROUND

Congenital heart defects (CHDs) have a complex etiology, and environmental factors play an important role in their occurrence. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous chemicals, and some have teratogenic potential. However, few studies have examined PAHs exposure and CHD risk. We investigated the association between PAHs in maternal scalp hair and CHD risk.

METHODS

A case-control study involving 170 severe CHD cases and 170 healthy controls was conducted, and the concentrations of 11 PAHs in maternal hair grown during the periconceptional period were quantified. A generalized linear mixed model (GLMM) was used to determine the effects of each PAHs on the risk for CHDs. Weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) were used to assess the overall effects of the 11-PAHs mixture on the risk for CHDs.

RESULTS

The median concentration of chrysene (CHR) was higher in CHD cases (9.75 ng/g) than in controls (6.50 ng/g). In GLMM, higher levels of CHR were associated with a 4.88-fold greater risk for CHDs (95 % confidence interval [CI]: 2.69-8.89). In WQS regression, higher levels of PAHs mixture were associated with a 2.03-fold greater CHD risk (95 % CI: 1.75-2.31), and CHR had the highest weighting (weighted 0.9346). In BKMR, CHD risks increased steadily with the levels of the PAHs mixture. CHR showed a toxic effect when the other PAHs were fixed at their 25th, 50th, or 75th percentile. No interactions among PAHs were found.

CONCLUSIONS

When examined individually, a high concentration of CHR in periconceptional maternal hair was associated with an increased risk for CHDs. When considering the 11 PAHs together, higher levels of the PAHs mixture were associated with increased odds of CHD occurrence.

Association Between Derivatives of Reactive Oxygen Metabolites and Hemodynamics in Children with Left-to-Right Shunt Congenital Heart Disease

Existing reports on the association between oxidative stress and pulmonary hemodynamics in congenital heart disease (CHD) are limited, and the relationship remains inadequately understood. To address this, we evaluated the link between oxidative stress and hemodynamics in children with left-to-right shunt CHD. We analyzed the derivatives of reactive oxygen metabolites (d-ROMs) in a cohort of 60 children with left-to-right shunt CHD and compared them to 60 healthy, age- and sex-matched controls. In the CHD group, hemodynamics measured by cardiac catheterization were evaluated in relation to d-ROMs. We also assessed the diagnostic performance of the d-ROMs for a pulmonary-to-systemic blood flow ratio (Qp/Qs) of >1.5. We found that the blood d-ROM levels in the CHD group were significantly higher than those in the control group (p < 0.001). A significant positive correlation was observed between d-ROMs and Qp/Qs (p < 0.001), d-ROMs and the ratio of the right ventricular end-diastolic volume (p < 0.001), d-ROMs and the mean pulmonary arterial pressure (p < 0.001), and d-ROMs and the ratio of the left ventricular end-diastolic volume (p = 0.007). In the receiver operating characteristic curve analysis, the area under the curve for d-ROMs in predicting Qp/Qs > 1.5 was 0.806 (p < 0.001), which, although not statistically significant, was higher than that of the plasma N-terminal pro-brain natriuretic peptide (0.716). These findings indicate that d-ROM levels are closely associated with hemodynamics and the disease severity in patients with left-to-right shunt CHD and may serve as a valuable marker for determining the need for surgical intervention.

Exploring potential causal links between air pollutants and congenital malformations: A two-sample Mendelian Randomization study

Observational studies have suggested an association between air pollutants and congenital malformations; however, conclusions are inconsistent and the causal associations have not been elucidated. In this study, based on publicly available genetic data, a two-sample Mendelian randomization (MR) was applied to explore the associations between particulate matter 2.5 (PM2.5), NOX, NO2 levels and 11 congenital malformations. Inverse variance weighted (IVW), MR-Egger and weighted median were used as analytical methods, with IVW being the main method. A series of sensitivity analyses were used to verify the robustness of the results. For significant associations, multivariable MR (MVMR) was utilized to explore possible mediating effects. The IVW results showed that PM2.5 was associated with congenital malformations of digestive system (OR = 7.72, 95 %CI = 2.33-25.54, P = 8.11E-4) and multiple systems (OR = 8.63, 95 %CI = 1.02-73.43, P = 0.048) risks; NOX was associated with circulatory system (OR = 4.65, 95 %CI = 1.15-18.86, P = 0.031) and cardiac septal defects (OR = 14.09, 95 %CI = 1.62-122.59, P = 0.017) risks; NO2 was correlated with digestive system (OR = 27.12, 95 %CI = 1.81-407.07, P = 0.017) and cardiac septal defects (OR = 22.57, 95 %CI = 2.50-203.45, P = 0.005) risks. Further MVMR analyses suggest that there may be interactions in the effects of these air pollutants on congenital malformations. In conclusion, this study demonstrated a causal association between air pollution and congenital malformations from a genetic perspective.

A recurrent missense variant in the E3 ubiquitin ligase substrate recognition subunit FEM1B causes a rare syndromic neurodevelopmental disorder

PURPOSE

Fem1 homolog B (FEM1B) acts as a substrate recognition subunit for ubiquitin ligase complexes belonging to the CULLIN 2-based E3 family. Several biological functions have been proposed for FEM1B, including a structurally resolved function as a sensor for redox cell status by controlling mitochondrial activity, but its implication in human disease remains elusive.

METHODS

To understand the involvement of FEM1B in human disease, we made use of Matchmaker exchange platforms to identify individuals with de novo variants in FEM1B and performed their clinical evaluation. We performed functional validation using primary neuronal cultures and in utero electroporation assays, as well as experiments on patient's cells.

RESULTS

Five individuals with a recurrent de novo missense variant in FEM1B were identified: NM_015322.5:c.377G>A NP_056137.1:p.(Arg126Gln) (FEM1BR126Q). Affected individuals shared a severe neurodevelopmental disorder with behavioral phenotypes and a variable set of malformations, including brain anomalies, clubfeet, skeletal abnormalities, and facial dysmorphism. Overexpression of the FEM1BR126Q variant but not FEM1B wild-type protein, during mouse brain development, resulted in delayed neuronal migration of the target cells. In addition, the individuals' cells exhibited signs of oxidative stress and induction of type I interferon signaling.

CONCLUSION

Overall, our data indicate that p.(Arg126Gln) induces aberrant FEM1B activation, resulting in a gain-of-function mechanism associated with a severe syndromic developmental disorder in humans.

Ecological assessment of stream water polluted by phosphorus chemical plant: Physiological, biochemical, and molecular effects on zebrafish (Danio rerio) embryos

The rapid development of the phosphorus chemical industry has caused serious pollution problems in the regional eco-environment. However, understanding of their ecotoxic effects remains limited. This study aimed to investigate the developmental toxicity of a stream polluted by a phosphorus chemical plant (PCP) on zebrafish embryos. For this, zebrafish embryos were exposed to stream water (0, 25, 50, and 100% v/v) for 96 h, and developmental toxicity, oxidative stress, apoptosis, and DNA damage were assessed. Stream water-treated embryos exhibited decreased hatching rates, heart rates, and body lengths, as well as increased mortality and malformation rates. The general morphology score system indicated that the swim bladder and pigmentation were the main abnormal morphological endpoints. Stream water promoted antioxidant enzymes (superoxide dismutase (SOD), peroxidase (POD), and glutathione peroxidase (GPx)), lipid peroxidation, and DNA damage. It also triggered apoptosis in the embryos' heads, hearts, and spines by activating apoptotic enzymes (Caspase-3 and Caspase-9). Additionally, stream water influenced growth, oxidative stress, and apoptosis-related 19 gene expression. Notably, tyr, sod (Mn), and caspase9 were the most sensitive indicators of growth, oxidative stress, and apoptosis, respectively. The current trial concluded that PCP-polluted stream water exhibited significant developmental toxicity to zebrafish embryos, which was regulated by the oxidative stress-mediated activation of endogenous apoptotic signaling pathways.

Impact of Oxidative Stress on Embryogenesis and Fetal Development

Multiple cellular processes are regulated by oxygen radicals or reactive oxygen species (ROS) where they play crucial roles as primary or secondary messengers, particularly during cell proliferation, differentiation, and apoptosis. Embryogenesis and organogenesis encompass all these processes; therefore, their role during these crucial life events cannot be ignored, more so when there is an imbalance in redox homeostasis. Perturbed redox homeostasis is responsible for damaging the biomolecules such as lipids, proteins, and nucleic acids resulting in leaky membrane, altered protein, enzyme function, and DNA damage which have adverse impact on the embryo and fetal development. In this article, we attempt to summarize the available data in literature for an in-depth understanding of redox regulation during development that may help in optimizing the pregnancy outcome both under natural and assisted conditions.