The gut-brain axis (GBA) represents an operant acting in a two-direction communication system between the gastrointestinal tract and the central nervous system, mediated by the enteric nervous system (ENS), vagus nerve, immune pathways, and endocrine signaling. In recent years, evidence has highlighted the pivotal role of the gut microbiota in modulating this axis, forming the microbiota-gut-brain axis (MGBA). Our review synthesizes current knowledge on the anatomical and functional substrates of gut-brain communication, focusing on interoceptive signaling, the roles of intrinsic primary afferent neurons (IPANs) and enteroendocrine cells (EECs) and the influence of microbial metabolites, including short-chain fatty acids (SCFAs), bile acids, and indoles. These agents modulate neurotransmission, epithelial barrier function, and neuroimmune interactions. The vagus nerve serves as a primary pathway for afferent sensory signaling from the gut influenced indirectly by the ENS and microbiota. Dysbiosis has been associated with altered gut-brain signaling and implicated in the pathophysiology of disorders ranging from irritable bowel syndrome to mood disorders and neurodegeneration. Microbial modulation of host gene expression via epigenetic mechanisms, including microRNAs, adds another layer of complexity. The gut has a crucial role as an active sensory and signaling organ capable of influencing higher-order brain functions. Understanding the MGBA has significant implications for new therapeutic interventions targeting the microbiome to manage neurogastroenterological and even neuropsychiatric conditions.

The oral microbiome plays a key role in oral cancer pathogenesis through mechanisms such as chronic inflammation, dysregulated proliferation, and increased tumor invasiveness. Dysbiosis, frequently present in premalignant and malignant lesions, may initiate or accelerate malignant transformation. Oral squamous cell carcinoma (OSCC), representing over 90% of oral cancers and affecting more than 350,000 people worldwide each year, is strongly linked to microbial shifts. Common periodontal pathogens such as Fusobacterium nucleatum and Porphyromonas gingivalis are often enriched in OSCC. These bacteria may promote tumorigenesis by activating NF-κB and STAT3 pathways, suppressing apoptosis, and modulating host immune responses. Additional potential mechanisms include the production of reactive oxygen species (ROS) and genotoxins, inhibition of tumor suppressors such as p53, disruption of cell-cycle regulation via cyclin-dependent kinase pathway, and upregulation of β-catenin and toll-like receptor signaling. These molecular alterations cause DNA damage, immune surveillance evasion, angiogenesis, promoting tumor progression. Microbiota-modulating therapies, such as Lactobacillus probiotics, may complement standard treatments by restoring balance, boosting immunity, and limiting tumor growth. Engineered bacteriotherapy, microbiome-targeted immunomodulators, and microbiota-based diagnostics expand therapeutic options in oral cancer and, combined with advances in precision medicine, may support more personalized treatments and improved outcomes.

Vitamin D deficiency is one of the most common medical conditions, with approximately one billion people having low vitamin D levels. Vitamin D is associated with a pleiotropic effect (immunomodulatory, anti-inflammatory and antiviral), which can be essential for a better immune response. The aim of this research was to evaluate the prevalence of vitamin D deficiency/insufficiency in hospitalized patients focusing on demographic parameters as well as assessing the possibility of its associations with different comorbidities. Of 11,182 Romanian patients evaluated in the study over 2 years, 28.83% had vitamin D deficiency, 32.11% insufficiency and 39.05% had optimal vitamin D levels. The vitamin D deficiency was associated with cardiovascular disorders, malignancies, dysmetabolic disorders and SARS-CoV2 infection, older age and the male sex. Vitamin D deficiency was prevalent and showed pathology association, while insufficiency of vitamin D (20–30 ng/mL) had lower statistical relevance and represents a grey zone in vitamin D status. Guidelines and recommendations are necessary for homogeneity of the monitoring and management of inadequately vitamin D status in the risk categories.

Non-alcoholic fatty liver disease (NAFLD) is the predominant cause of chronic liver conditions, and its progression is marked by evolution to non-alcoholic steatosis, steatohepatitis, cirrhosis related to non-alcoholic steatohepatitis, and the potential occurrence of hepatocellular carcinoma. In our systematic review, we searched two databases, Medline (via Pubmed Central) and Scopus, from inception to 5 February 2024, and included 73 types of research (nine clinical studies and 64 pre-clinical studies) from 2854 published papers. Our extensive research highlights the impact of Berberine on NAFLD pathophysiology mechanisms, such as Adenosine Monophosphate-Activated Protein Kinase (AMPK), gut dysbiosis, peroxisome proliferator-activated receptor (PPAR), Sirtuins, and inflammasome. Studies involving human subjects showed a measurable reduction of liver fat in addition to improved profiles of serum lipids and hepatic enzymes. While current drugs for NAFLD treatment are either scarce or still in development or launch phases, Berberine presents a promising profile. However, improvements in its formulation are necessary to enhance the bioavailability of this natural substance.

Hepatocellular adenomas are benign endothelial tumors of the liver, mostly associated with female individual users of estrogen-containing medications. However, the precise factors underlying the selective development of hepatic adenomas in certain females remain elusive. Additionally, the conventional profile of individuals prone to hepatic adenoma is changing. Notably, male patients exhibit a higher risk of malignant progression of hepatocellular adenomas, and there are instances where hepatic adenomas have no identifiable cause. In this paper, we theorize the role of the human gastrointestinal microbiota, specifically, of bacterial species producing β-glucuronidase enzymes, in the development of hepatic adenomas through the estrogen recycling pathway. Furthermore, we aim to address some of the existing gaps in our knowledge of pathophysiological pathways which are not yet subject to research or need to be studied further. As microbial β-glucuronidases proteins recycle estrogen and facilitate the conversion of inactive estrogen into its active form, this process results in elevated levels of unbound plasmatic estrogen, leading to extended exposure to estrogen. We suggest that an imbalance in the estrobolome could contribute to sex hormone disease evolution and, consequently, to the advancement of hepatocellular adenomas, which are estrogen related.

Anomalies in lipid metabolism involve multifactorial pathogenesis, among other factors, being associated with an inflammatory state and disturbances in vitamin D status. The literature has focused on the binary relationships between inflammation and dyslipidemia, vitamin D and dyslipidemia, or vitamin D and inflammation. Our study aimed to explore the link between all these three factors: 25-OH vitamin D serum levels, the presence of inflammation assessed through serum C-reactive protein (CRP), and serum lipid profile in 2747 hospitalized patients. Our results showed a positive correlation of HDL-C with 25 (OH) vitamin D and a negative correlation of HDL-C with CRP. This relationship had different patterns in the statistical network analysis. The network analysis patterns are preserved for males and females, except for the relationship between CRP and vitamin D, which is present in male cases and absent in females. The same triangular relationship between all three—CRP, vitamin D, and HDL-C was found with different strengths of partial correlation in obese and non-obese patients. This pattern was similar in patients with and without fatty liver. A shifted pattern was found in the network analysis of hypertensive patients. The CRP was negatively correlated with vitamin D and HDL-C, and vitamin D was positively correlated with HDL-C in non-hypertensive patients. Castelli’s Risk indexes I and II were positively associated with CRP, suggesting that increased cardiovascular risk is proportional to an inflammatory state. The triad formed by altered serum lipid levels, inflammation, and vitamin D represents a complex relationship marked by specific dynamics between lipidic fractions such as HDL-C and C-reactive protein and vitamin D.