Aging is a complex biological process characterized by a progressive decline in physiological functions and an increased risk of chronic diseases. A key mechanism of this process is cellular senescence, the permanent arrest of the cell cycle in response to stress or damage, which contributes to the accumulation of dysfunctional cells in tissues. Recent research has highlighted the role of polyphenols, bioactive compounds present in numerous plant-based foods, in positively modulating these processes. Polyphenols exert antioxidant effects, regulate gene expression and improve mitochondrial function, helping to delay cellular aging and prevent age-related diseases. In addition, some polyphenols exhibit senolytic properties, selectively eliminating senescent cells and promoting tissue regeneration. This review summarizes the current evidence on the effects of polyphenols on aging and cellular senescence, exploring the underlying molecular mechanisms and discussing their potential in nutritional strategies aimed at promoting healthy aging.

Many patients with irritable bowel syndrome (IBS) have a compromised intestinal barrier associated with low-grade inflammation. Polyunsaturated fatty acids (PUFAs) are potential mediators of inflammation: omega-6 PUFAs are pro-inflammatory, while omega-3 PUFAs are antioxidant and anti-inflammatory. Zonulin is a potential biomarker for small intestinal permeability (s-IP). This study investigated the relationship between PUFAs and gastrointestinal (GI) barrier integrity in IBS patients with predominant diarrhea (IBS-D). We evaluated GI barrier function indicators in the urine and bloodstream and erythrocyte membrane PUFA composition in 38 IBS-D patients (5 men, 33 women, 44.11 ± 1.64 years), categorized at baseline by fecal zonulin levels into high (≥107 ng/mL, H-FZ) and normal (<107 ng/mL N-FZ) groups. Evaluations were conducted prior to and following a 12-week diet low in FODMAPs (LFD). At baseline, H-FZ patients had s-IP significantly higher than the reference value, lower n-3 PUFAs levels, and higher n-6/n-3 PUFAs and arachidonic acid (AA) to eicosapentaenoic acid (EPA) ratios than N-FZ. After LFD, H-FZ patients showed significant increases in n-3 PUFAs levels; decreases in n-6 PUFAs, n-6/n-3 PUFAs and AA/EPA ratios; and improved s-IP. The n-6/n-3 PUFAs ratio positively correlated with fecal zonulin levels in all subjects. These findings highlight the relationship between PUFAs and the intestinal barrier, suggesting their role in IBS-D pathophysiology and confirming the positive effects of LFD in managing IBS-D.

Navelina oranges (Citrus sinensis) are rich in phytonutrients and bioactive compounds, especially flavonoids like hesperidin. This study investigates the anti-inflammatory and anti-fibrotic properties of hesperidin (HE) and a polyphenol mixture from Navelina oranges (OE) in human hepatocytes (Hepa-RG) and hepatic stellate cells (LX-2), in order to elucidate the underlying molecular mechanisms. In Hepa-RG cells, HE treatment increased expression of cannabinoid receptor 2 (CB2R), which was associated with down-regulation of p38 mitogen-activated protein kinases (p38 MAPK) but had minimal impact on cyclooxygenase-2 (COX-2) and transforming growth factor-β (TGF-β) levels. Conversely, OE treatment not only enhanced CB2R levels and reduced p38 MAPK, but also promoted a significant reduction in both COX-2 and TGF-β levels, suggesting that OE might be more effective in mitigating inflammatory and fibrotic processes than HE. In LX-2 cells, HE treatment caused a notable decrease in both COX-2 and TGF-β levels, reflecting its efficacy in targeting fibrosis-associated inflammation. OE treatment, on the other hand, reduced Nuclear Factor-Kappa B p65 (NF-κB) expression, a critical transcription factor involved in inflammatory responses, though it did not significantly affect COX-2. LX-2 cells induced to fibrosis with TGF-β and treated with HE and OE showed a reduction in the expression levels of several fibrosis markers. In addition, HE and OE showed antioxidant effects by increasing protein levels of Cu, Zn superoxide dismutase (SOD1), Mn superoxide dismutase (SOD2) and catalase (CAT) and influencing the state of lipid peroxidation. Further research is needed to explore the effects of the treatments in activated hepatic stellate cells and in vivo liver disease models.

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.

Background: Patients with irritable bowel syndrome (IBS) often experience comorbid psychological conditions, notably depression and anxiety. Evidence suggests that these conditions are linked to gut barrier dysfunction, dysbiosis, and chronic inflammation. All these factors are central to IBS pathophysiology and mood disturbances. Polyunsaturated fatty acids (PUFAs) play crucial roles in modulating inflammation and depression. This study examined the associations among intestinal permeability, PUFA profiles, low-grade inflammation, and depression severity in IBS patients with diarrhea (IBS-D). Methods: Forty-three IBS-D patients (7 men, 36 women; 44.56 ± 1.52 years) were categorized into depressed (IBS-D(d+)) and non-depressed (IBS-D(d−)) groups according to scores on the depression subscale of the Symptom Checklist-90-Revised (SCL-90-R). Biomarkers of small intestinal permeability (s-IP) were assessed in urine and blood, alongside erythrocyte membrane PUFA composition, dysbiosis, and inflammation indices. Results: IBS-D (d+) patients exhibited elevated s-IP and altered PUFA metabolism compared to their IBS-D (d−) counterparts. Additionally, in the first group, omega-3 PUFA concentrations inversely correlated with s-IP biomarkers, while the omega-6/omega-3 ratio showed a positive correlation. Moreover, depression severity is significantly associated with s-IP markers and omega-3 PUFA levels. Lastly, IBS-D (d+) patients exhibited higher levels of dysbiosis and pro-inflammatory cytokines than IBS-D (d−) patients. Conclusions: These findings highlight the interplay between intestinal barrier integrity and PUFA metabolism in IBS-D patients with depression, suggesting that s-IP markers and erythrocyte PUFA profiles could represent novel therapeutic targets for managing depression in this population. This study was registered on ClinicalTrials.gov (NCT03423069), with a date of registration of 30 January 2018.

Background/Objectives: Metabolic dysfunction-associated fatty liver disease (MAFLD) is currently the most common cause of chronic liver disease. Systemic inflammatory status and peripheral metabolic symptoms in the clinical picture have an impact on gut commensal bacteria. Methods: Our designed clinical trial was based on a cohort of patients with MAFLD whose diet included the daily consumption of 400 g of “Navelina” oranges for 28 days, compared with a control group of patients with the same pathologic conditions whose diet did not include the consumption of oranges and other foods containing similar nutrients/micronutrients. We used 16S metataxonomics and GC/MS analyses to identify taxa and urine/fecal VOCs, respectively. Results: A set of micronutrients from the diet were inspected, and some specific fatty acids were identified as the main contributors in terms of cluster sample separation. Metataxonomics and metabolomics profiles were obtained, and a stringent statistical approach allowed for the identification of significant taxa/VOCs, which emerged from pairwise group comparisons in both fecal and urine samples. Conclusions: In conclusion, a set of taxa/VOCs can be directly referred to as a marker of dysbiosis status and other comorbidities that, together, make up the pathologic burden associated with MAFLD. The investigated variables can be a target of therapeutic strategies.