Pomegranate derivative urolithin A enhances vitamin D receptor signaling to amplify serotonin-related gene induction by 1,25-dihydroxyvitamin D

Preventing Recurrent Otitis Media in Children Aged 2-7 Years: A Cross-Sectional Evaluation of Serum Vitamin D as a Modifiable Factor

Background/Objectives: Otitis media (OM) is a common pediatric condition that significantly impacts hearing, language development, and quality of life. Emerging evidence suggests that vitamin D plays a crucial role in immune regulation and that deficiency may predispose children to recurrent OM. This study aimed to evaluate whether low serum vitamin D levels are associated with increased incidence and severity of OM in children aged 2-7 years. Methods: A cross-sectional study was conducted at a pediatric otolaryngology clinic in northwest Romania between November 2023 and April 2024. A total of 118 children were enrolled, including 87 children with documented episodes of OM within the preceding six months and 31 quasi-controls without recent OM episodes. Participants were stratified into three age groups (2-3, 4-5, and 6-7 years) and classified into clinical subtypes of OM (Acute Suppurative Otitis Media, Serous Otitis Media, and Acute Congestive Otitis Media). Serum 25-hydroxyvitamin D levels were measured using a chemiluminescence immunoassay and categorized as deficient (≤20 ng/mL), insufficient (21-29 ng/mL), or sufficient (≥30 ng/mL). Statistical analyses included one-way ANOVA with post-hoc tests, chi-square tests, linear regression, logistic regression, and Poisson regression. Results: Children with OM exhibited significantly lower vitamin D levels compared to controls, with the most pronounced deficiency observed in the Acute Suppurative OM group. One-way ANOVA revealed significant differences among the groups (F(3,114) = 82.30, p < 0.001), and linear regression demonstrated a strong inverse correlation between vitamin D levels and the frequency of OM episodes (r = -0.793, adjusted R2 = 0.63, p < 0.001). Logistic regression indicated that vitamin D insufficiency significantly increased the odds of OM (OR ≈ 120.74, p < 0.001), while Poisson regression showed incidence rate ratios of 13.62 for deficient and 10.47 for insufficient vitamin D status (p < 0.001). Conclusions: The findings indicate that low serum vitamin D levels are significantly associated with an increased risk and frequency of otitis media in preschool-aged children. These results support the role of vitamin D deficiency as an independent, modifiable risk factor for recurrent OM, suggesting that vitamin D screening and supplementation could be beneficial in reducing the clinical and economic burden of this condition.

A drug-like molecule engages nuclear hormone receptor DAF-12/FXR to regulate mitophagy and extend lifespan

Autophagy-lysosomal function is crucial for maintaining healthy lifespan and preventing age-related diseases. The transcription factor TFEB plays a key role in regulating this pathway. Decreased TFEB expression is associated with various age-related disorders, making it a promising therapeutic target. In this study, we screened a natural product library and discovered mitophagy-inducing coumarin (MIC), a benzocoumarin compound that enhances TFEB expression and lysosomal function. MIC robustly increases the lifespan of Caenorhabditis elegans in an HLH-30/TFEB-dependent and mitophagy-dependent manner involving DCT-1/BNIP3 while also preventing mitochondrial dysfunction in mammalian cells. Mechanistically, MIC acts by inhibiting ligand-induced activation of the nuclear hormone receptor DAF-12/FXR, which, in turn, induces mitophagy and extends lifespan. In conclusion, our study uncovers MIC as a promising drug-like molecule that enhances mitochondrial function and extends lifespan by targeting DAF-12/FXR. Furthermore, we discovered DAF-12/FXR as a previously unknown upstream regulator of HLH-30/TFEB and mitophagy.

Microbiota mitochondria disorders as hubs for early age-related macular degeneration

Age-related macular degeneration (AMD) is a progressive neurodegenerative disease affecting the central area (macula lutea) of the retina. Research on the pathogenic mechanism of AMD showed complex cellular contribution governed by such risk factors as aging, genetic predisposition, diet, and lifestyle. Recent studies suggested that microbiota is a transducer and a modifier of risk factors for neurodegenerative diseases, and mitochondria may be one of the intracellular targets of microbial signaling molecules. This review explores studies supporting a new concept on the contribution of microbiota-mitochondria disorders to AMD. We discuss metabolic, vascular, immune, and neuronal mechanism in AMD as well as key alterations of photoreceptor cells, retinal pigment epithelium (RPE), Bruch's membrane, choriocapillaris endothelial, immune, and neuronal cells. Special attention was paid to alterations of mitochondria contact sites (MCSs), an organelle network of mitochondria, endoplasmic reticulum, lipid droplets (LDs), and peroxisomes being documented based on our own electron microscopic findings from surgically removed human eyes. Morphometry of Bruch's membrane lipids and proteoglycans has also been performed in early AMD and aged controls. Microbial metabolites (short-chain fatty acids, polyphenols, and secondary bile acids) and microbial compounds (lipopolysaccharide, peptidoglycan, and bacterial DNA)-now called postbiotics-in addition to local effects on resident microbiota and mucous membrane, regulate systemic metabolic, vascular, immune, and neuronal mechanisms in normal conditions and in various common diseases. We also discuss their antioxidant, anti-inflammatory, and metabolic effects as well as experimental and clinical observations on regulating the main processes of photoreceptor renewal, mitophagy, and autophagy in early AMD. These findings support an emerging concept that microbiota-mitochondria disorders may be a crucial pathogenic mechanism of early AMD; and similarly, to other age-related neurodegenerative diseases, new treatment approaches should be targeted at these disorders.

Health functions and related molecular mechanisms of ellagitannin-derived urolithins

Ellagitannins are vital bioactive polyphenols that are widely distributed in a variety of plant-based foods. The main metabolites of ellagitannins are urolithins, and current research suggests that urolithins provide a variety of health benefits. This review focused on the role of the gut bacteria in the conversion of ellagitannins to urolithins. Based on the results of in vitro and in vivo studies, the health benefits of urolithins, including antioxidant, anti-inflammatory, anti-cancer, anti-obesity, anti-diabetic, anti-aging, cardiovascular protective, neuroprotective, kidney protective, and muscle mass protective effects, were thoroughly outlined, with a focus on their associated molecular mechanisms. Finally, we briefly commented on urolithins' safety. Overall, urolithins' diverse health benefits indicate the potential utilization of ellagitannins and urolithins in the creation of functional foods and nutraceuticals to treat and prevent some chronic diseases.

A mechanistic insight into the biological activities of urolithins as gut microbial metabolites of ellagitannins

Urolithins are the gut metabolites produced from ellagitannin-rich foods such as pomegranates, tea, walnuts, as well as strawberries, raspberries, blackberries, and cloudberries. Urolithins are of growing interest due to their various biological activities including cardiovascular protection, anti-inflammatory activity, anticancer properties, antidiabetic activity, and antiaging properties. Several studies mostly based on in vitro and in vivo experiments have investigated the potential mechanisms of urolithins which support the beneficial effects of urolithins in the treatment of several diseases such as Alzheimer's disease, type 2 diabetes mellitus, liver disease, cardiovascular disease, and various cancers. It is now obvious that urolithins can involve several cellular mechanisms including inhibition of MDM2-p53 interaction, modulation of mitogen-activated protein kinase pathway, and suppressing nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activity. Antiaging activity is the most appealing and probably the most important property of urolithin A that has been investigated in depth in recent studies, owing to its unique effects on activation of mitophagy and mitochondrial biogenesis. A recent clinical trial showed that urolithin A is safe up to 2,500 mg/day and can improve mitochondrial biomarkers in elderly patients. Regarding the importance of mitochondria in the pathophysiology of many diseases, urolithins merit further research especially in clinical trials to unravel more aspects of their clinical significance. Besides the nutritional value of urolithins, recent studies proved that urolithins can be used as pharmacological agents to prevent or cure several diseases. Here, we comprehensively review the potential role of urolithins as new therapeutic agents with a special focus on the molecular pathways that have been involved in their biological effects. The pharmacokinetics of urolithins is also included.

4-Chloro-3-formylcoumarin as a multifaceted building block for the development of various bio-active substituted and fused coumarin heterocycles: a brief review

This review presents the diverse synthesis of 3,4-substituted coumarins and 5-, 6- and 7-membered ring fused coumarins using 4-chloro-3-formylcoumarin as the precursor via classical reactions including metal-catalyzed and green reaction protocols.