Search Results (428)

The hormonal vitamin D metabolite, 1,25-dihydroxyvitamin D (1,25D), produced primarily in the kidney, acts in numerous end-organs via the nuclear vitamin D receptor (VDR) to trigger molecular events that orchestrate bone mineral homeostasis, immune responsiveness, and aspects of behavior. Tyrosine hydroxylase (TH) encodes a neuronally expressed enzyme that catalyzes the initial, rate-limiting step in the production of several catecholamine neurotransmitters and hormones, including dopamine, norepinephrine, and epinephrine. Herein we report that TH mRNA is significantly induced (2.5-fold) and NURR1 mRNA is induced 9.3-fold by 10 nM 1,25D in differentiated human SH-SY5Y neuroblastoma cells. Similar results were observed in human U87 glioblastoma cells (TH, 2.6-fold; NURR1, 3.6-fold). Comparative analysis of TH gene promoter-proximal sequences from human, mouse, and rat identifies candidate NURR1-responsive elements (NBREs) at the following positions: −35, −855, −1470, and −2343 bp in the human gene; −34 and −961 bp in the mouse gene; and −34, −350, and −873 bp in the rat gene, consistent with NURR1 acting as a recurring regulatory factor at TH promoters across mammalian species. Furthermore, by interrogating VDR ChIP-seq/cistrome datasets, we identified candidate vitamin D-responsive elements (VDREs) at the human NURR1 locus that provide a plausible genomic framework for direct regulation of NURR1 by 1,25D/VDR. We propose that 1,25D-liganded VDR acts as a primary inducer of NURR1, which in turn secondarily activates expression of the TH gene, thereby defining a transcriptional route through which 1,25D/VDR signaling may influence TH-linked dopaminergic gene programs. Retinoid X receptor (RXR) may facilitate both NURR1-dependent and -independent potentiation of TH transcription because the rexinoid, bexarotene, significantly enhances TH mRNA in human U87 cells, either alone (2.0-fold) or in combination with 1,25D (4.1-fold). In addition, bexarotene and its novel analogs, A41 and A55, induce NURR1 mRNA expression in U87 cells by 2.8-, 3.1-, and 4.8-fold, respectively, with A55 outperforming the parent compound at matched concentration. Because Parkinson’s disease is characterized by the selective degeneration of dopaminergic neurons and impaired NURR1-dependent transcriptional programs, our findings identify a 1,25D/VDR–NURR1–RXR transcriptional axis as a previously underappreciated regulatory framework for studying TH gene expression and dopaminergic gene regulation in Parkinson’s disease-relevant neural contexts. Full article

Background/Objectives: Vitamin D deficiency and insufficiency represent a widespread problem in the majority of Central Asian countries, attributable to the geographical location of the region, urbanization, and dietary patterns of the population. Given that vitamin D not only participates in the regulation of calcium and phosphate metabolism but also exerts pleiotropic effects on various organs and systems, its insufficiency and deficiency are associated with a broad spectrum of pathological conditions, ranging from asymptomatic manifestations to severe clinical symptoms, including the development of autoimmune diseases, metabolic disorders, cardiovascular, gynecological and reproductive, and rheumatological conditions. The development of national and interdisciplinary guidelines addressing the diagnosis, prevention of insufficiency, and correction of vitamin D deficiency in the countries of Central Asia represents an important step toward the establishment of effective preventive programs and treatment strategies, which may contribute to a reduction in the prevalence of diseases associated with vitamin D deficiency. The aim of the present work is to formulate a resolution capturing the conclusions and recommendations derived from an interdisciplinary expert discussion. Methods: An Expert Council meeting with the participation of specialists in endocrinology, obstetrics and gynecology, rheumatology, clinical pharmacology, and other medical disciplines from Central Asian and European countries was conducted in Almaty (Kazakhstan) on 18 June 2025. During this meeting, the pleiotropic action of vitamin D was extensively discussed basing on RCTs and observational studies. Results: Following the Expert Council meeting, current international clinical guidelines, scientific research data, and relevant epidemiological evidence were reviewed, leading to the formulation of a resolution that reflects the agreed-upon recommendations for the prevention of vitamin D insufficiency and the correction of vitamin D deficiency across different age groups according to baseline vitamin D metabolite levels. Conclusions: The expert discussion emphasized the need for unified interdisciplinary approaches to the diagnosis, correction, and prevention of vitamin D deficiency in the countries of Central Asia. The proposed recommendations may serve as a foundation for the development of national clinical protocols and the implementation of effective preventive and therapeutic strategies in the countries of Central Asia. Full article

Myopia is increasingly recognized as an inflammatory ocular disease. Vitamin D₃ is a potential modulator of the gut–eye axis, but its role in inflammation-induced myopia remains unclear. This study investigated whether vitamin D₃ supplementation attenuates myopia progression by regulating retinal inflammation, gut microbiota composition, and microbiota-derived metabolites in a TGF-β2–induced myopia model. Three-week-old Brown Norway rats received weekly periocular TGF-β2 injections with or without daily oral vitamin D₃, and myopia development was evaluated on days 1 and 21 by axial length and refractive error. Cecal contents were analyzed for α- and β-diversity and taxonomic differences, and day-21 serum underwent untargeted metabolomic profiling of microbiota-derived metabolites, including bile acids and imidazole derivatives; Spearman correlation linked microbial or metabolic alterations with myopia progression. TGF-β2 induced axial elongation, myopic refractive shifts, and upregulated retinal pro-inflammatory cytokines (p-NFκB, IL-1β, TNF-α), while vitamin D₃ supplementation markedly attenuated myopia progression and retinal inflammation. Cecal α-diversity did not differ among control, vitamin D₃, TGF-β2, and TGF-β2+vitamin D₃ groups, but vitamin D₃ significantly reshaped β-diversity and reduced the Firmicutes/Bacteroidota ratio. Distinct metabolite profiles were observed, with the vitamin D₃ group showing reduced hyodeoxycholic acid and elevated imidazole derivatives (imidazolepropionic and methylimidazoleacetic acids). Vitamin D₃ supplementation attenuated myopia progression by reducing retinal inflammation and concurrently reshaping the gut microbiome and its metabolites compared to the control and myopic groups. These results underscore the potential of vitamin D₃ to modulate the gut–retina axis as a nutritional approach for mitigating myopia development. Full article

Chiang Mai, Thailand, experiences seasonal fine particulate matter (PM_2.5) pollution associated with metabolic diseases, but the underlying mechanisms remain unclear. This prospective observational study compared plasma metabolomes of 25 healthy adults in Samoeng District, a highly affected area, between low and high PM_2.5 exposure seasons using proton nuclear magnetic resonance (¹H-NMR) spectroscopy. Twenty-six metabolites differentiating haze and non-haze seasons were identified using PLS-DA (VIP > 1.5). During the haze season, 11 were elevated, whereas 15 were decreased. Among the elevated metabolites, the top five—maleylacetoacetic acid, deoxyribose 5-phosphate, betaine, 3-hydroxyanthranilic acid, and 1-methyladenosine—were associated with inflammation, increased reactive oxygen species, nitric oxide inhibition, and altered amino acid metabolism. The top five decreased metabolites—deoxyguanosine, D-arabitol, glycerophosphocholine, ophthalmic acid, and oxaloacetic acid—were involved in several metabolic pathways, particularly those involved in energy metabolism. A total of 56 metabolic pathways were altered by high PM_2.5 exposure, including pathways related to amino acids, lipids, sugars, nucleotides, vitamins, and energy metabolism. High PM_2.5 exposure disrupts metabolites and pathways, inducing inflammation, oxidative stress, impaired lipid/energy metabolism, insulin resistance, and high blood pressure. These alterations may increase the risk of metabolic and cardiovascular diseases, with dysregulated metabolites serving as potential biomarkers. These findings highlight the molecular impact of air pollution in affected populations and may support preventive strategies and public health policy development in affected regions. Further studies are needed to clarify these findings. Full article

Vitamin D is a fat-soluble secosteroid essential for skeletal development and calcium homeostasis, but it also exerts pleiotropic effects on numerous biological processes via its active metabolites. Vitamin D metabolites act as steroid hormones that regulate cell-cycle progression, proliferation, differentiation, apoptosis, immune responses, and multiple intracellular signaling pathways. Moreover, they modulate the expression of genes involved in carcinogenesis. As circulating vitamin D levels are influenced by diet, fortified foods, and supplementation, they represent a potentially modifiable factor. Whether vitamin D status affects cancer risk or disease progression in carriers of pathogenic BRCA1 variants remains unclear and continues to be actively investigated. Clarifying this relationship could have significant clinical implications for risk stratification and prevention in this high-risk population. This narrative review summarizes current evidence from epidemiological, clinical, and molecular studies examining the role of vitamin D in BRCA1 pathogenic variant carriers. It also highlights key limitations in the existing literature and identifies critical directions for future research, emphasizing the need for well-designed prospective studies in representative cohorts. Full article

Background/Objectives: Vitamin D, universally recognized for its role in calcium–phosphate homeostasis and skeletal health, has emerged as a key immuno-endocrine modulator. Its active metabolite interacts with the vitamin D receptor (VDR) across immune and endocrine cell populations, influencing gene transcription, cytokine balance, and immune tolerance. This narrative review synthesizes mechanistic, epidemiological, and clinical evidence on the role of vitamin D in immune modulation across autoimmune and infectious diseases. Methods: This narrative review incorporated a structured and comprehensive literature search across PubMed/MEDLINE, Scopus, Web of Science, Embase, and Google Scholar. Results: Vitamin D modulates both innate and adaptive immunity through antimicrobial peptide induction, macrophage and NK cell activation, and promotion of tolerogenic dendritic cells. Clinical and interventional trial outcomes remain heterogeneous and are influenced by baseline vitamin D status, dosing regimens, genetic variability, and disease context. Conclusions: Vitamin D functions in endocrine and immune regulation, contributing to host defense and immune tolerance. Current evidence supports that for autoimmune and infectious conditions, well-designed randomized trials are required to clarify effective dosing, identify responsive subpopulations, and elucidate genetic determinants of therapeutic benefit. Full article

The vitamin D receptor (VDR) plays a pivotal role in maintaining epidermal barrier homeostasis and regulating cutaneous inflammatory responses. However, the cosmetic application of vitamin D and its active metabolites is limited by photoinstability, formulation challenges, and regulatory considerations. In this study, we evaluated a synthetic VDR-activating peptide (VDR-Pep) as a potential functional cosmetic ingredient capable of modulating VDR-associated signaling pathways in human keratinocytes. In situ proximity ligation assays (PLAs) demonstrated that VDR-Pep enhanced the heterodimerization of VDR and retinoid X receptor (RXR), indicating activation of canonical VDR signaling. Treatment with VDR-Pep significantly increased the expression of S100A3 and key terminal differentiation markers, including filaggrin, involucrin, and loricrin, in a dose-dependent manner. In addition, VDR-Pep stimulated intracellular calcium mobilization at levels comparable to or exceeding those induced by 1,25-dihydroxyvitamin D₃. Under UVB-induced stress conditions, the peptide attenuated the expression of the pro-inflammatory cytokine interleukin-6 (IL-6) and enhanced NRF2-associated transcriptional engagement, as evidenced by increased interaction between NRF2 and RNA polymerase II. Collectively, these findings suggest that VDR-Pep supports epidermal homeostasis through coordinated modulation of VDR/RXR signaling, calcium-mediated differentiation, barrier-related protein expression, inflammatory responses, and antioxidant-associated pathways. The results indicate that VDR-targeting peptides may represent a promising non-hormonal strategy for cosmetic formulations aimed at reinforcing skin barrier function and improving resilience to environmental stress. Future studies should focus on validating these effects in in vivo human skin models, assessing long-term safety and efficacy, and optimizing formulation stability for practical cosmetic applications. Full article

Alterations in fat-soluble vitamins are well documented in humans with inflammatory bowel disease; however, data in dogs with chronic enteropathy and inflammatory protein-losing enteropathy (iPLE) are limited. This prospective case–control study compared serum concentrations of vitamins A, D, and E metabolites in dogs with iPLE and healthy controls and evaluated associations with selected clinicopathological variables at diagnosis (T0) and after one month of therapy (T1). Fifty-eight dogs with iPLE and 50 healthy dogs were enrolled. Twenty dogs with iPLE were available for evaluation at T1. iPLE was defined by chronic gastrointestinal signs, hypoalbuminemia of gastrointestinal origin, and histologic evidence of benign intestinal inflammation with or without lymphangiectasia. Serum retinol, 25-hydroxyvitamin D, and α-tocopherol concentrations were measured by HPLC at T0 and T1. At T0, all vitamin concentrations were significantly lower in iPLE dogs (p < 0.0001). A weak positive correlation was found between retinol and α-tocopherol concentrations. No differences were observed according to treatment, diet, or histopathologic findings. At T1, retinol concentrations increased (p = 0.01), whereas vitamin D and E metabolite concentrations did not. Dogs fed homemade low-fat diets had lower vitamin D concentrations. These findings indicate decreased serum concentrations of multiple fat-soluble vitamins in dogs with iPLE, suggesting altered fat-soluble vitamin homeostasis, with only partial recovery after treatment. Full article

Background/Objectives: Canine athletes have a higher energy requirement and are more susceptible to nutrient depletion, electrolyte imbalance, and metabolic stress than sedentary pets. The objective of this study was to characterize the plasma metabolome of American Foxhound dogs following a bout of unstructured exercise. Methods: Thirty-nine adult American Foxhound dogs (32 intact males, 7 spayed females; age: 6.2 ± 3.1 yr; BW: 36.3 ± 5.3 kg) were allotted to a standard performance diet (CTRL) or NUTRO^® Natural Choice^® Adult High Endurance Formula (TEST). After 80 d in the study, blood samples were collected prior to (0 h), and 3 h and 25 h post-exercise (average: 17.7 km run over 2–3 h). Plasma samples of the 10 top performers of each treatment group were analyzed for untargeted metabolite profiling. Results: Of the 566 named metabolites identified, >200 and >185 metabolites were impacted (p < 0.05) by exercise and diet, respectively. Principal component analysis indicated distinct clustering by diet. Random forest analysis highlighted several metabolites having a high degree of predictive accuracy based on diet and exercise, with most related to amino acid, lipid, xenobiotic, and cofactor and vitamin metabolism. Relating to exercise, glycolytic end-products and citric acid cycle intermediates were increased at 3 h post-exercise. Similarly, tocopherols and omega-3 polyunsaturated fatty acids were higher in dogs fed TEST than those fed CTRL during recovery, indicating a lower oxidative stress and anti-inflammatory response. Conclusions: Overall, the data suggest a protective effect (lower susceptibility to oxidative stress and muscle fatigue) of feeding a nutrient-fortified diet for dogs undergoing unstructured exercise. Full article

The active vitamin D metabolite, 1,25-dihydroxycholecalciferol [1,25(OH)₂D], exerts its biological effects through binding to the vitamin D receptor (VDR), a ligand-activated transcription factor regulating the expression of genes involved in calcium and phosphate homeostasis, immune modulation, and cell proliferation and differentiation. In addition to direct transcriptional regulation, 1,25(OH)₂D signaling also involves epigenetic mechanisms. A total of 90 studies were included in this narrative review, comprising experimental studies (n = 45), observational studies (n = 17), population-based studies (n = 8), interventional studies (n = 15), and mixed-design studies (n = 5). Experimental studies in cell cultures and animal models demonstrate that 1,25(OH)₂D may affect several major epigenetic regulatory pathways, including chromatin remodeling, DNA methylation, histone modifications, and the expression of non-coding RNAs, particularly microRNAs. Preclinical evidence suggests that the epigenetic actions of 1,25(OH)₂D are involved in metabolic regulation, immune responses, bone development, fibrotic processes, carcinogenesis, ageing, and fetal programming. However, evidence from observational studies and randomized controlled trials remains limited and inconclusive. Some studies have reported alterations in miRNA expression, methylation of selected loci, and epigenetic age markers. The clinical relevance of 1,25(OH)₂D–mediated epigenetic regulation has not yet been fully established. The interpretation of available findings is limited by substantial heterogeneity in study populations, exposure and intervention protocols, environmental factors, interindividual variability in response to vitamin D supplementation associated with genetic polymorphisms and methylation status, and the restricted range of analyzed cell types. This subject requires randomized controlled trials integrating molecular endpoints with clinically relevant outcomes. Full article

Vitamin D₃ is an essential fat-soluble vitamin for the human body. Its metabolite, 25-hydroxyvitamin D₃ (25(OH)D₃), serves as the primary biomarker to assess vitamin D levels. The monitoring of 25(OH)D₃ concentration is crucial for human health assessment. While traditional detection methods offer high sensitivity and accuracy, they are operationally complex and costly. This review systematically summarizes the most recent progress in 25(OH)D₃ detection technologies. Special attention is given to the recognition modes of 25(OH)D₃ by antibodies, nucleic acids, and molecularly imprinted recognition elements. Subsequently, the design strategies of diverse types of biosensors, including fluorescent, colorimetric, and electrochemical biosensors, are analyzed. Moreover, the development of portable devices, smartphone software, and flexible wearable devices for detection applications is also examined. Biosensing detection platforms are compared from the perspectives of target recognition, signal conversion, signal output, and application scenarios. Additionally, the potential of biosensor detection platforms in clinical diagnosis, health management, and community health surveillance is further investigated. Finally, the future trends of intelligent, portable, accurate, and home-use 25(OH)D₃ detection systems are delineated. This review offers a comprehensive reference for researchers developing next-generation 25(OH)D₃ diagnostic sensors and provides insights for the early prevention and treatment of vitamin D deficiency-related diseases. Full article

Objectives: To investigate the interplay between adipose distribution, vitamin D metabolites, and bone mineral density (BMD) in Normal Glucose Tolerance (NGT) and type 2 Diabetic (T2DM) individuals. Methods: 167 participants (NGT: 61; T2DM: 106) were enrolled. Serum 25(OH)D, 1,25(OH)₂D₃, Parathyroid Hormone (PTH), and Ca were quantified. Visceral (VAT) and subcutaneous (SAT) adipose areas were assessed via dual bioelectrical impedance analysis. BMD and body composition were assessed via DXA. Metabolic indices (HOMA-IR, HOMA-β, ISI) were calculated. Results: 1. NGT: 25(OH)D was unrelated to adiposity. Conversely, 1,25(OH)₂D₃ was correlated inversely with VAT, SAT, body mass index (BMI), and Fat Mass Index (FMI), with VAT being the strongest independent predictor. 2. T2DM: High VAT correlated with insulin resistance yet paradoxically higher BMD. 25(OH)D correlated positively with Z-score, while 1,25(OH)₂D₃ correlated negatively with lumbar BMD. 3. VAT exerted a greater influence on insulin resistance than SAT, particularly in T2DM. Conclusions: 1. Visceral adiposity is the primary determinant of active 1,25(OH)₂D₃ metabolism in both NGT and T2DM individuals. 2. 1,25(OH)₂D₃ levels may be more closely associated with adiposity-related metabolic alterations than 25(OH)D. Despite lower 1,25(OH)₂D₃, the positive association between VAT and BMD in T2DM suggests complex mechanisms where visceral fat may paradoxically influence bone metabolism while driving insulin resistance. Full article

Ergosterol is a fungal sterol with broad pharmacological activities, including anticancer, anti-inflammatory, cholesterol- and uric acid-lowering effects, and serves as the precursor of vitamin D₂. Despite its therapeutic potential, poor aqueous solubility, physicochemical instability, and low oral bioavailability severely limit its clinical application. This review provides an integrative overview of the physicochemical properties, biosynthesis, biological activities, underlying molecular mechanisms, pharmacokinetics, and safety profiles of ergosterol and its major derivatives. A structured literature search was conducted in PubMed, Web of Science, Scopus and CNKI up to February 2026, with findings critically synthesized across preclinical models. Current evidence links ergosterol-related interventions to changes in signaling pathways such as PI3K/Akt, NF-κB, and Wnt/β-catenin, although direct target-engagement evidence remains limited for many disease models. The review concludes that while ergosterol represents a promising natural scaffold for drug development, translational progress is constrained by limited human pharmacokinetic data and insufficient exposure–response validation. Future research should prioritize metabolite profiling, clinically relevant dosing strategies, and formulation optimization to better define the translational potential of ergosterol-based compounds. Full article

Introduction: Intermittent fasting (IF) is becoming increasingly popular as a method of weight management, but it is unknown whether it affects plasticiser intake with resultant changes in glycaemic control in diabetes and vitamin D (VitD) levels; therefore, this study was undertaken in a cohort of control and type-2 diabetic (T2D) subjects during Ramadan time-restricted feeding (TRF). Methods: In T2D subjects (n = 19) and controls (n = 31) undertaking TRF, 24 h urinary levels of phthalate metabolites, bisphenols and serum VitD were determined pre- and post-TRF by liquid chromatography–tandem mass spectrometry (LC-MS/MS). Anthropometric data and glycosylated haemoglobin (HbA1c) were measured. Results: T2D subjects were older (52 versus 36.73 years, p < 0.001), and had higher BMI (36.54 versus 27.67 kg/m², p < 0.001), body weight (101.77 versus 80.36 kg, p < 0.001), and HbA1c (8.38 versus 5.46%, p < 0.001) compared to controls, while VitD levels did not differ (60.43 versus 63.95 nmol/L, p > 0.05). Post-TRF, HbA1c was unchanged in T2D subjects and there was no difference in weight, BMI or VitD. Increased mono-iso-butyl phthalate (MiBP) in T2D subjects (10 versus 6.1 ng/mL, p = 0.001) and mono-n-butyl phthalate (MnBP) in T2D subjects (37 versus 13 ng/mL, p = 0.018) and controls (8.3 versus 5.4 ng/mL, p = 0.007) were observed post-TRF; however, significance was lost after adjusting for baseline differences in age, BMI, and HbA1c using a general linear model (GLM) repeated-measures ANOVA. Despite having no median differences in DEHP (di-2-ethylhexyl phthalate) metabolites pre- and post-TRF, analyses revealed a significant time × HbA1c interaction for [mono(2-ethyl-5-carboxypentyl) phthalate, MECPP: F(1,42) = 4.79, p = 0.03, mono(2-ethyl-5-hydroxyhexyl) phthalate, MEHHP: F(1,42) = 8.56, p = 0.006, mono(2-ethylhexyl) phthalate, MEHP: F(1,42) = 4.64, p = 0.03 and mono(2-ethyl-5-oxohexyl) phthalate, MEOHP: F(1,42) = 8.19, p = 0.007] and time × group interactions [MEHHP: F(1,42) = 14.27, p < 0.001, MEHP: F(1,42) = 6.35, p = 0.01 and MEOHP: F(1,42) = 10.30, p = 0.003]. Estimated marginal means (adjusted for age, BMI, HbA1c, and VitD) further confirmed higher concentrations of DEHP metabolites [MECPP, MEHHP, MEHP, and MEOHP] in T2D participants over time compared with controls. Additionally, monomethyl phthalate (MMP) trajectories were significantly influenced by the time × group interaction (F(1,42) = 4.28, p = 0.04), with post-TRF elevations observed in T2D subjects. Vitamin D status was observed to modify mono(3-carboxypropyl) phthalate (MCPP) and MEP trajectories over time. Conclusion: Ramadan TRF is associated with changes in plasticiser metabolite levels, with estimated increased levels in T2D subjects versus healthy controls. Metabolite levels were influenced by HbA1c and vitamin D, though BMI was not observed to be a contributing factor. Full article

Background/Objectives: The escalating crisis of antibiotic resistance and the inherent limitations of conventional antibiotics necessitate the development of innovative therapeutic strategies. Targeted drug delivery (TDD) offers a powerful approach to enhance efficacy, minimize systemic toxicity, and circumvent bacterial resistance. This systematic review aims to evaluate the potential of unique bacterial transport systems (BTSs), surface specific receptors and intracellular enzymes as platforms for TDD via the “Trojan Horse” strategy (THS). Methods: A comprehensive literature review was conducted, focusing on studies that investigated the specificity and mechanisms of BTSs responsible for the uptake of metabolites that are essential for and unique to bacteria. This includes an analysis of transport systems for siderophores, bacteria-specific sugars, cell wall components, D-amino acids, and vitamins. We assessed preclinical and clinical examples of drug conjugates utilizing these pathways, as well as emerging platforms such as bacteriophage-derived proteins, antibody–antibiotic conjugates, and bacterial extracellular vesicles (EVs). Results: BTSs demonstrate high specificity for their cognate substrates, providing effective molecular gateways for TDD of drugs photosensitizers and diagnostic probes in form of conjugates. The siderophore–cephalosporin conjugate cefiderocol represents a clinically validated example, having received FDA approval. Preclinical studies further reveal that conjugates utilizing sugars (e.g., maltose, trehalose) and vitamins (e.g., B12) can significantly enhance antibiotic uptake and activity against both Gram-positive and Gram-negative pathogens, including drug-resistant strains. Emerging platforms like bacteriophage endolysins and engineered EVs show promise for overcoming biological barriers such as bacterial outer membranes and intracellular host niches. Conclusions: The THS leveraging BTSs represents a clinically viable and promising avenue for next-generation antibacterial therapies. Advantages of BTS include overcoming bacterial resistance, such as reduced membrane permeability and efflux pumps, enabling the “revival” of antibiotics that are poorly permeable or toxic, increasing their local concentration at the target site and reducing side effects on host cells. While significant progress has been made, a striking disconnect persists between the hundreds of conjugates demonstrating potent in vitro activity and the limited agent that has achieved clinical use. This in vitro–in vivo gap reflects, in large part, the early stage of this field rather than a fundamental failure. Further research is critically needed not only to identify novel BTSs and optimize drug-linker chemistry, but also to systematically address the translational barriers—including poor pharmacokinetics, immunogenicity, and unexpected toxicity—that have prevented most promising candidates from advancing beyond preclinical evaluation. Full article