The gut-brain axis serves as a crucial communication pathway, with microbial metabolites such as short-chain fatty acids (SCFAs) playing a central role in regulating neuroinflammation and maintaining neuronal health. The gut microbiota’s impact on neurodevelopment is highlighted, particularly its relevance to autism, anxiety, and other psychiatric conditions. In this review, we explored the intricate relationship between the gut microbiota (GM) and the central nervous system (CNS), emphasizing the bidirectional communication that forms the gut-brain axis. Associations between specific gut microbiota and neurodegenerative diseases are explored, focusing on the role of certain bacteria in processes such as amyloid aggregation and neuroinflammation in Alzheimer’s disease (AD) and Parkinson’s disease (PD). The potential for therapeutic modulation of the gut microbiota is discussed, with a focus on dietary interventions and probiotics as strategies to improve outcomes in neurodegenerative diseases by restoring gut health. We concluded by emphasizing the significance of understanding the gut-brain connection and calls for further research to investigate therapeutic approaches targeting the gut microbiome for brain health.

Background: The European Commission has called for a harmonised front-of-package nutritional label (FOPNL) system in the European region. The Keyhole is a widely adopted positive FOPNL used in several Nordic countries. The Nutri-Score is a five-level graded FOPNL, more recently introduced in Western Europe. Both FOPNLs are supported by intrinsically different nutrient profiling systems (NPSs). A third NPS is the Choices NPS, which originally supported a positive FOPNL similar to the Keyhole and has been expanded into a five-level NPS. Objectives: The main objective of this study was to investigate the overall alignment between both the Choices and Nutri-Score multi-level NPSs and the Keyhole NPS. Furthermore, food group-based alignment was analysed to understand the main sources of misalignment. Methods: In this study, we extracted 1064 food/drink items from the food and beverage database of the Swedish Food Administration. All products were assessed according to all three NPSs, and alignment was assessed, using the Keyhole NPS as a recommendation-based reference. Two definitions of alignment were examined—healthier (more lenient, i.e., two highest grades) and healthiest (stricter, i.e., only the highest grade). Results: The overall alignment between the Choices and Keyhole NPSs was similar to that between the Nutri-Score and Keyhole NPSs (89% and 85% alignment under the healthiest definition, i.e., stricter). However, two food groups showed poor alignment between the Nutri-Score NPS and the Keyhole NPS (~60%). Under the healthier (more lenient) definition, the alignment for both the Choices and Nutri-Score systems with the Keyhole system was lower (86% and 79%). Conclusions: The alignments and misalignments between the Choices/Nutri-Score systems and the Keyhole system prompt important considerations for future developments of FOPNL systems for the Nordic countries. Extending the Keyhole NPS to include a multi-level criterion could potentially help consumers identify healthier choices, even for less nutritious foods.

Serotonin (5-hydroxytryptamine, 5-HT) is a multifaceted neuromodulator involved in processes from early embryogenesis to postnatal brain maturation. During pregnancy, 5-HT plays critical roles not only in maternal mood and behavior but also in placental function and fetal brain development. Beyond its classical role in mood regulation, 5-HT acts as a developmental signal influencing neuronal proliferation, migration, and synaptic organization within precisely timed critical windows. This narrative review provides an integrative framework linking molecular, cellular, and systems-level 5-HT mechanisms to neurodevelopmental outcomes, emphasizing how maternal, placental, and fetal sources of 5-HT dynamically interact with genetic, environmental, and pharmacological factors during gestation. By considering recent advances from developmental neurobiology, genetics, and psychopharmacology, we propose that disrupted 5-HTergic homeostasis represents a convergent mechanism underlying neurodevelopmental risk, particularly in autism spectrum disorder (ASD). We further highlight emerging evidence for sex-dependent 5-HTergic signaling and its role in differential susceptibility across offspring. These results collectively indicate the key role of 5-HT in neurodevelopment and highlight its promise as a biomarker and therapeutic target in neurodevelopmental disorders.

Background: Homeostasis of water content in the brain during fetal development is of crucial physiological importance. Aquaporins (AQPs) play a critical role in maintaining brain water balance, supporting normal brain development, and are increasingly recognized for their relevance in understanding neurodevelopmental disorders. Summary: This review provides a comprehensive overview of AQPs and their essential roles in the central nervous system (CNS), specifically AQP4, AQP11, and AQP9, which play a crucial role in water transport in the brain, maintaining water homeostasis and facilitating water movement across cell membranes. The review also highlights how disruptions in AQP expression and function may contribute to the pathology of neurodevelopmental disorders such as autism and Fragile X syndrome. Key Messages: AQPs are vital for brain water regulation and normal neural development. Altered expression or function of AQPs can impact blood-brain barrier integrity, neuroinflammation, and synaptic activity. AQP dysfunctions are linked to neurodevelopmental disorders and may represent promising therapeutic targets.

Introduction: Staphylococcus epidermidis (SE) is a predominant hospital-acquired bacterium leading to late-onset sepsis in preterm infants. Recent findings have suggested that postnatal SE infection is associated with short-term neurodevelopmental consequences. However, the potential effects of postnatal SE infection on long-term neuronal plasticity and cognitive functions, which are sensitive to early life brain insults, remain unclear. In light of these findings, we investigated the effects of postnatal SE infection on recognition memory function using a neonatal mouse model. Methods: On postnatal day 4, male and female C57Bl/6 mice were injected intraperitoneally with either 3.5 × 107 colony-forming units of SE or sterile saline. On postnatal day 45 (±5 days), the mice were subjected to the novel object recognition test (NORT) to assess recognition memory function. Following NORT, the brains of the mice were collected for neuronal plasticity analyses by considering maturation of neurons and 3-D analysis of synaptic plasticity and hippocampal, measuring the nerve growth factor (NGF) expression. Results: Postnatal SE infection induced long-term, sex-specific effects on recognition memory and hippocampal neuroplasticity. Female SE-infected mice showed enhanced recognition memory, whereas males showed no significant difference in the recognition memory after neonatal SE infection. At the cellular level, both sexes displayed a significant decrease in doublecortin-positive neurons in the dentate gyrus after SE infection, indicating impaired neuroplasticity. However, male mice showed increased spine density, particularly of immature thin spines and disrupted spatial organization of spines, while females demonstrated no change in spines. Notably, SE infection elevated hippocampal NGF expression in males, but not in females, suggesting sex-specific molecular responses that may contribute to the observed differences in neuroplasticity and cognitive outcomes. Conclusion: This study demonstrates that postnatal SE infection induces long-lasting, sex-specific changes in recognition memory. Early life immune activation disrupted hippocampal neuroplasticity, with males showing greater vulnerability. These findings indicate distinct neurodevelopmental trajectories shaped by neonatal immune challenges in preterm infants, with implications for understanding sex-specific cognitive outcomes.