Purpose of Review This narrative review comprehensively analyzes VLEKT as an advanced nutritional strategy for obesity management. The focus is on the beneficial effects on key disease organs, such as adipose tissue and liver, as well as the modulation of intestinal permeability and its fundamental role in influencing the gut microbiota and inflammatory pathways. Recent Findings The impact of VLEKT on obesity-related comorbidities, including metabolic syndrome, cardiovascular disease, endocrine disorders, metabolic dysfunction-associated steatotic liver disease (MASLD), neurological disorders, and kidney alterations, is also investigated. Moreover, to assess its wider application in obesity treatment, the combination of ketogenic regimes with additional strategies such as physical activity, bariatric surgery, and digital health technologies is examined. Despite promising clinical results, adherence to VLEKT and potential nutritional deficiencies require careful follow-up and individualized programming monitored by specialists. Future research should focus on elucidating the molecular mechanisms underlying the effects on physiological systems, and long-term safety. Nevertheless, VLEKT is an innovative approach to obesity treatment, offering a target-oriented and highly effective strategy for people fighting against overweight and its associated medical complications. Summary Obesity is a multifactorial and chronic disease associated with numerous comorbidities; given its increasing prevalence, effective and personalized intervention strategies are crucial to inhibit the “obesity pandemic” according to a “food re-educational” protocol. Among dietary interventions, the ketogenic diet (KD) has attracted attention for its effectiveness in weight management and metabolic benefits. A variant, the very low-calorie ketogenic diet (VLCKD), more recently defined as very low-energy ketogenic diet (VLEKD), combines the metabolic benefits of ketosis with substantial calorie restriction, improving overall health. Graphical Abstract

Background. Very low-calorie ketogenic diets (VLCKD) are an effective weight-loss strategy for obese individuals, reducing risks of liver conditions such as non-alcoholic steatohepatitis and fibrosis. Small extracellular vesicles (sEVs) are implicated in liver fibrosis by influencing hepatic cell phenotypes and contributing to liver damage. This study investigates sEVs derived from serum of 60 obese adults categorized into low fibrosis risk (LR) and intermediate/high fibrosis risk (IHR) groups based on FibroScan elastography (FIB E scores, limit value 8 kPa) and all participants underwent an 8-week VLCKD intervention. Methods. The study examines the impact of these sEVs on fibrosis markers, inflammation, and autophagy in a hepatocyte cell line (HEPA-RG) using bioinformatics, RNA sequencing, lipidomics, RT-PCR, and Western blotting before (T0) and after (T1) VLCKD. Results. sEVs from LR patients post-VLCKD reduced fibrosis related gene expression (e.g., ACTA2) and enhanced proteins associated with regeneration and inflammation (e.g., HDAC6). Conversely, sEVs from IHR patients increased fibrosis and inflammation related gene expression (PIK3CB, AKT1, ACTA2) in hepatocytes, raising concerns about VLCKD suitability for IHR patients. IHR sEVs also decreased expression of HDAC10, HDAC6, HDAC3, MMP19, and MMP2, while increasing modulation of p-AKT, α-SMA, and VIM. Conclusion. These findings underscore the critical role of sEVs in regulating inflammation, remodeling, and hepatic stress responses, particularly in IHR patients, and suggest sEVs could complement instrumental evaluations like FibroScan in fibrosis assessment.

The VLCKD is a diet recognized to promote rapid fat mobilization and reduce inflammation, hepatic steatosis, and liver fibrosis. Extracellular vesicles (EVs) mediate cell-to-cell communication. The aim of the study is to investigate the role of circulating EVs in cell proliferation, ketone bodies, and ROS production in patients on an 8-week VLCKD regimen. Participants were classified as responders (R) or non-responders (NR) to VLCKD treatment based on their fibroscan results. In vitro experiments with the hepatic cell lines HEPA-RG (normal hepatocytes) and LX-2 (stellate cells) were conducted to investigate the effects of circulating EVs on cell viability, ROS production, and ketone body presence. The findings reveal a notable reduction in cell viability in both cell lines when treated with exosomes (EXOs). In contrast, treatment with microvesicles (MVs) did not appear to affect cell viability, which remained unchanged. Additionally, the levels of ketone bodies measured in urine were not consistently correlated with the reduction of fibrosis in responders (R). Similarly, an increase in ketone bodies was observed in non-responders (NR), which was also not aligned with the expected reduction in fibrosis. This inconsistency stands in stark contrast to the levels of Reactive Oxygen Species (ROS), which exhibited a clear and consistent pattern in accordance with the dietary intervention. Finally, in this preliminary study, ROS has been identified as a potential diet adherence marker for VLCKD patients; the ROS levels reliably follow the progression of the fibrosis response, providing a more accurate reflection of the therapeutic effects.

Background: Gastric cancer (GC) is a highly aggressive disease often complicated by resistance to chemotherapy agents like paclitaxel (PTX), which targets microtubules to induce apoptosis. Resistance arises through complex molecular mechanisms, including the overexpression of pro-angiogenic factors (VEGFA, ANG-2), activation of survival pathways (PDGFRβ, PPARγ), and epithelial-mesenchymal transition (EMT) driven by proteins such as VIM, E-CAD, N-CAD, and FLOT-1. The extracellular matrix (ECM), regulated by COL1A1 and influenced by PPARγ, acts as a physical barrier to drug penetration. Small extracellular vesicles (sEVs) have emerged as critical mediators of intercellular communication and may influence these resistance pathways. Methods: This study investigated the role of sEVs isolated from metastatic GC patients treated with Ramucirumab and PTX. Patients were stratified by progression-free survival (PFS) into rapidly progressing (RP) and controlled disease (CD) groups. sEVs from these patients were applied to HCEC-1CT and HEPA-RG cell lines. Cell viability assays, gene and protein expression analyses, and bioinformatic studies were conducted to assess the impact of sEVs on resistance-related markers. Results: Results showed that sEVs from CD patients reduced the expression of markers associated with drug resistance, while sEVs from RP patients increased these markers, promoting angiogenesis, EMT, and ECM remodeling. These changes correlated with enhanced cell survival and resistance phenotypes. Bioinformatic analyses confirmed that sEVs modulate inflammation, ECM dynamics, and EMT pathways. Conclusions: In conclusion, sEVs from metastatic GC patients significantly influence chemoresistance and tumor progression. Targeting sEV-mediated signaling may offer novel therapeutic strategies to overcome resistance and improve treatment outcomes in gastric cancer.

Crohn’s disease (CD) is a type of inflammatory bowel disease (IBD) affecting the gastrointestinal tract that can also cause extra-intestinal complications. Following exposure to the mRNA vaccine BNT162b2 (Pfizer-BioNTech) encoding the SARS-CoV-2 Spike (S) protein, some patients experienced a lack of response to the biological drug Adalimumab and a recrudescence of the disease. In CD patients in progression, resistant to considered biological therapy, an abnormal increase in intestinal permeability was observed, more often with a modulated expression of different proteins such as Aquaporin 8 (AQP8) and in tight junctions (e.g., ZO-1, Claudin1, Claudin2, Occludin), especially during disease flares. The aim of this study is to investigate how the SARS-CoV-2 vaccine could interfere with IBD therapy and contribute to disease exacerbation. We investigated the role of the SARS-CoV-2 Spike protein, transported by extracellular vesicles (EVs), and the impact of various EVs components, namely, exosomes (EXOs) and microvesicles (MVs), in modulating the expression of molecules involved in the exacerbation of CD, which remains unknown.

Background/Objectives: Ketogenic diets induce profound metabolic reprogramming; however, their impact on systemic metabolism in patients with hepatic fibrosis remains insufficiently characterized. This study aimed to investigate serum metabolic changes induced by Very Low Energy Ketogenic Therapy (VLEKT) and to assess the influence of hepatic fibrosis development on these metabolic adaptations. Methods: Fifty serum samples from 25 obese patients were analyzed using 1D 1H CPMG NMR spectroscopy at baseline (T0) and after 8 weeks of VLEKT (T1). Patients were stratified according to the FIB-E fibrosis index into a low-risk group (LR; FIB-E < 8) and an intermediate-high-risk group (IHR; FIB-E ≥ 8) for hepatic fibrosis onset. Results: An integrated approach combining NMR-based metabolomics and pathway enrichment analysis revealed a marked metabolic shift following VLEKT, characterized by increased ketone bodies (including β-hydroxybutyric acid and acetone), together with changes in amino acids and lipid-related signals. Among these, acetone provided a robust and quantifiable NMR signal, consistent with enhanced ketogenesis. Stratified analysis indicated differential metabolic flexibility: LR patients exhibited enhanced modulation of tricarboxylic acid (TCA) cycle-related metabolites, whereas IHR patients showed persistent alterations in aromatic amino acids and lipid signals. Significant correlations between tyrosine and β-alanine with clinical biochemical markers further supported the presence of a fibrosis-dependent metabolic signature. Conclusions: These findings highlight the potential of circulating metabolites as sensitive and non-invasive indicators of hepatic vulnerability and determinants of metabolic adaptability to VLEKT. Moreover, the study underscores the value of NMR-based metabolomics as an innovative tool for improving the non-invasive assessment of metabolic and hepatic health.