Search Results (220)

Intercellular junctions are involved in the regulation of epithelial function and remodeling in the female reproductive system; however, their importance in the avian oviduct is poorly known. The aim of this study was: first, to provide information on the expression and localization of key tight (occludin, claudin 1, 4, 5, junctional adhesion molecule [JAM] 2, 3) and adherens (E-cadherin, β-catenin) junction proteins in the hen oviduct, and second, to compare expression and localization of these molecules between laying and subjected to fasting-induced pause in laying hens. Tissue samples from all oviductal segments, i.e., infundibulum, magnum, isthmus, shell gland, and vagina were collected on the sixth day of the experiment from the control hens and hens that had been fasted for five consecutive days. Specific oviductal part-dependent expression patterns of examined genes (by quantitative real-time polymerase chain reaction [qRT-PCR]) and/or proteins (by Western blotting) were found, with the highest mRNA transcript and protein abundances in the infundibulum, shell gland, and vagina, and the lowest in the magnum. Fasting-induced partial regression of the oviduct was accompanied by alterations in mRNA transcript and protein abundances of examined molecules. Reduced staining intensity of immunoreaction (analyzed by immunofluorescence) for occludin, E-cadherin, and β-catenin proteins was observed in the oviduct of non-laying hens. Our results indicate the potential involvement of these proteins in controlling intercellular communication, cell signaling, paracellular permeability, and mucosal barrier functionality, which impact the functioning of the hen oviduct. Furthermore, our observations provide novel insights into the molecular composition of tight and adherens junctions and its contribution to the remodeling of the oviduct during its regression induced by fasting. Full article

Psychological stress is deeply involved in the pathophysiology of gastrointestinal diseases. We investigated the effect of psychological stress on the small-intestinal environment, including gut flora, immune system, and mucosal integrity in mice subjected to chronic social defeat stress (CSDS). CSDS mice were established by exposing a C57BL/6N mouse to an ICR aggressor mouse. Stool samples were obtained to investigate its properties and the gut microbiome profile. Using small-intestinal tissues, the expression of cytokines, antimicrobial peptides, and tight junction proteins (TJPs) were examined by real-time RT-PCR and immunohistochemistry. Small-intestinal permeability was evaluated by transepithelial electrical resistance assay. For stool properties, mean Bristol scale score and fecal water content were significantly lower in the CSDS group. Pseudomonadota and Patescibacteria were significantly more abundant in the stools from CSDS mice. Among TJPs and antimicrobial peptides, the expression of Occludin, Claudin-4, and Regenerating gene IIIγ was significantly decreased in the small intestine epithelium of CSDS mice. The small-intestinal permeability was significantly increased in CSDS mice. Lipopolysaccharide immunoreactivity, the number of macrophages, and proinflammatory IL-1β expression were significantly increased in the small intestine of CSDS mice. These findings suggest that psychological stress is associated with mucosal barrier dysfunction and microinflammation in small-intestinal tissues. Full article

Background/Objectives: Intranasal delivery is a promising approach for targeting the central nervous system (CNS); however, most of the drugs show poor permeability through the nasal mucosa. Nanocarriers such as liposomes can improve nasal drug absorption; however, the surface charge of liposomes has a key role in the nasal mucosal uptake process. Therefore, the present study aimed to formulate and compare the intranasal applicability of oppositely charged liposomes loaded with donepezil hydrochloride (DPZ) as CNS-active model compound using two different charge inducers, the negatively charged dicethyl phosphate (DCP) and the positively charged stearylamine (SA). Methods: Liposomes were prepared with a fixed phosphatidylcholine (PC)/cholesterol (CH) 7:2 molar ratio, while the effect of DCP and SA was studied in a 0.5:2 molar ratio. The most important properties for intranasal administration were studied, e.g., colloidal parameters, drug release and permeability behavior, and mucoadhesion. Results: It has been revealed that the reduction in liposome vesicle size is directly proportional to the amount of DCP, while it is inversely proportional to the amount of SA. This was also supported by the drug release studies—the lower vesicle size resulted in faster drug release. Both charge inducers increased the drug encapsulation efficiency (~60–80%) through tighter packing or increased spacing of the lipid bilayer structure. DCP also improved the in vitro nasal permeability compared to the initial DPZ solution. The positively charged SA showed more remarkable mucoadhesive properties than DCP. Conclusions: We can conclude that both charge inducers can be useful for improving nasal absorption of liposomal carriers, DCP in higher (PC:CH:DCP 7:2:2), while SA in lower concentrations (PC:CH:SA 7:2:0.5). Full article

Background/Objectives: This study aimed to enhance the vaginal permeation of buserelin acetate (BA), a synthetic gonadotropin-releasing hormone (GnRH) analogue, by evaluating various permeation enhancers (PEs) using a validated reversed-phase high-performance liquid chromatography (RP-HPLC) method and an ex vivo porcine vaginal model. Methods: A robust RP-HPLC method was developed and validated according to ICH Q2 (R2) guidelines to enable accurate quantification of BA in permeation samples. The analytical method demonstrated high specificity, linearity (R² = 0.9999), accuracy (98–102%), precision (%RSD < 2%), robustness, and stability. Using this method, ex vivo permeation studies were conducted with six different PEs: 2-hydroxypropyl-β-cyclodextrin, sodium dodecyl sulfate, poloxamer 188, Span 80, Tween 80, and chitosan. Results: Among all tested PEs, chitosan demonstrated the best enhancement of BA permeation. It achieved the highest flux (J) (0.64 ± 0.03 × 10⁻² µg/cm²·h) and apparent permeability coefficient (P_app) (16.20 ± 0.84 × 10⁻⁵ cm/h), both of which were statistically significantly higher (p < 0.05) than those of all other enhancer groups. Kinetic modelling indicated a non-Fickian, biphasic permeation mechanism best described by the Makoid–Banakar model. Conclusions: These findings highlight chitosan’s potential as an effective intravaginal delivery vehicle for peptide therapeutics and establish the validated HPLC method as a reliable platform for future formulation development and translational studies in mucosal drug delivery. Full article

This study focuses on the issue of whether orally administered zinc (gluconate) (26 mg BID) can induce the remodeling of gastrointestinal barrier function and reduce passive leak across the human intestinal mucosal barrier in situ. Increased transmucosal leak has been implicated in diseases as diverse and seemingly unconnected as Inflammatory Bowel Disease (IBD), Celiac Disease, Autism Spectrum Disorders and Alzheimer’s Dementia. Our current investigation represents the first patient-based study to examine the effect of zinc on gastrointestinal epithelial tight junctions and gastrointestinal barrier leak in otherwise healthy test subjects. Using independent test subject groups for each endpoint, three separate molecular analyses indicated that zinc treatment can achieve a positive outcome: (1) RNA-seq analyses of intestinal biopsies showed salutary patterns of gene transcription changes dealing with not only transcripts of junctional proteins but also transcripts mitigating the proinflammatory state, as well as dedifferentiation (both modulators of tight junction permeability); (2) Western immunoblot analyses of intestinal tissue indicated that tight junctional protein expression was being modified by the administered zinc, most notably Claudin-2 and Tricellulin; (3) zinc treatment induced a reduction in serum levels of a functional marker of passive intestinal leak, namely the GI microbiome metabolite D-Lactate. The data collectively suggest that orally administered zinc can induce remodeling of the intestinal epithelial barrier, resulting in the reduction in GI barrier leak. The overall safety and economy of supplement levels of zinc suggest that this micronutrient could be efficacious as an adjuvant therapy to reduce the condition known as leaky gut, and possibly therefore be protective regarding diseases postulated to involve leaky gut. Full article

Backgrounds and aim: Protective effects of natural compounds have been suggested in the prevention and treatment of radiation-induced mucositis or bacterial infections. In this study, the protective effects of proanthocyanidin-rich grape seed extract (GSE) on bacterial Lipopolysaccharide (LPS) and radiation-induced epithelial barrier damage and Reactive Oxygen Species (ROS) production were investigated in an in vitro model. Methods: Human intestinal epithelial cells Caco-2, previously treated with LPS, GSE, or LPS + GSE, were irradiated with 10 Gy divided into five daily treatments. Epithelial barrier integrity and ROS production were measured before and after each treatment. Results: Irradiation, at different doses, significantly increased intestinal permeability and ROS production; pretreatment with GSE was able to significantly prevent the increased intestinal permeability (4.63 ± 0.76 vs. 15.04 ± 1.5; p < 0.05) and ROS production (12.9 ± 1.08 vs. 1048 ± 0.5; p < 0.0001) induced by irradiation treatment. When the cells were pretreated with LPS, the same results were observed: GSE cotreatment was responsible for preventing permeability alterations (5.36 ± 0.16 vs. 49.26 ± 0.82; p < 0.05) and ROS production (349 ± 1 vs. 7897.67 ± 1.53; p < 0.0001) induced by LPS exposure when added to the irradiation treatment. Conclusions: The results of the present investigation demonstrated, in an in vitro model, that GSE prevents the damage to intestinal permeability and the production of ROS that are induced by LPS and ionizing radiation, suggesting a potential protective effect of this extract on the intestinal mucosa during irradiation treatment. Full article

Donepezil (DPZ) is an Alzheimer’s disease (AD) drug that promotes cholinergic neurotransmission and exhibits excellent acetylcholinesterase (AChE) selectivity. The current oral formulations of DPZ demonstrate decreased bioavailability, attributed to limited drug permeability across the blood–brain barrier (BBB). In order to overcome these limitations, various dosage forms aimed at delivering DPZ have been explored. This discussion will focus on the nose-to-brain (N2B) delivery system, which represents the most promising approach for brain drug delivery. Intranasal (IN) drug delivery is a suitable system for directly delivering drugs to the brain, as it bypasses the BBB and avoids the first-pass effect, thereby targeting the central nervous system (CNS). Currently developed formulations include lipid-based, solid particle-based, solution-based, gel-based, and film-based types, and a systematic review of the N2B research related to these formulations has been conducted. According to the in vivo results, the brain drug concentration 15 min after IN administration was more than twice as high those from other routes of administration, and the direct delivery ratio of the N2B system improved to 80.32%. The research findings collectively suggest low toxicity and high therapeutic efficacy for AD. This review examines drug formulations and delivery methods optimized for the N2B delivery of DPZ, focusing on technologies that enhance mucosal residence time and bioavailability while discussing recent advancements in the field. Full article

Background/Objectives: The oral cavity represents a convenient route of administration for drugs that exhibit significant hepatic first-pass extraction. In this study, the mucosal permeation properties of selected active pharmaceutical ingredients (APIs) incorporated into oral cavity drug products that are approved by the U.S. Food and Drug Administration were quantified using the human-derived sublingual HO-1-u-1 and buccal EpiOral™ in vitro tissue models. Methods: Epithelial barrier properties were monitored using propranolol and Lucifer Yellow as prototypic transcellular and paracellular markers. APIs were dissolved in artificial saliva, pH 6.7, and transepithelial flux from the apical to the basolateral compartment was quantified using HPLC. Results: Apparent permeability coefficients (Papp) calculated for these APIs in the sublingual HO-1-u-1 tissue model varied from Papp = 2.72 ± 0.06 × 10⁻⁵ cm/s for asenapine to Papp = 6.21 ± 2.60 × 10⁻⁵ cm/s for naloxone. In contrast, the buccal EpiOral™ tissue model demonstrated greater discrimination power in terms of permeation properties for the same APIs, with values ranging from Papp = 3.31 ± 0.83 × 10⁻⁷ cm/s for acyclovir to Papp = 2.56 ± 0.68 × 10⁻⁵ cm/s for sufentanil. The tissue-associated dose fraction recovered at the end of the transport experiment was significantly increased in the buccal EpiOral™ tissue model, reaching up to 8.5% for sufentanil. Conclusions: Experimental permeation data collected for selected APIs in FDA-approved oral cavity products will serve as a training set to aid the development of predictive computational models for improving algorithms that describe drug absorption from the oral cavity. Following a robust in vitro–in vivo correlation analysis, it is expected that such innovative in silico modeling strategies will the accelerate development of generic oral cavity products by facilitating the utility of model-integrated evidence to support decision making in generic drug development and regulatory approval. Full article

Background: PTEN is a tumor suppressor that controls many pathophysiological pathways, including cell proliferation, differentiation, apoptosis and invasiveness. Although PTEN down-modulation is a critical event in neoplastic progression, it becomes apparent that transient and local inhibition of PTEN activity might be beneficial for the healing process. Methods: In the present study, we investigated the impact of PTEN invalidation in mouse intestinal epithelium under a physiological condition and after dextran sulfate sodium (DSS) treatment to induce experimental colitis. PTEN conditional knockout was induced in intestinal epithelial cells after crossing villin-Cre and PTEN^flox/flox mice. Results: PTEN invalidation alleviates experimental colitis induced by DSS, as evidenced by decreased weight loss during the acute phase, the lower expression of inflammation markers, including the proinflammatory cytokines IFN-γ, CXCL1 and CXCL2, reduced mucosal lesions, and faster recovery after resolution of inflammation. This protective effect might result in part from the sustained proliferation of colonic epithelium, leading to hyperplasia and increased colonic crypt depth under physiological conditions, which was further exacerbated in the vicinity of mucosal injury induced by DSS treatment. Furthermore, PTEN knockout decreased paracellular permeability, thereby enhancing the intestinal barrier function. This process was associated with the reinforcement of claudin-3 immunostaining, especially on the surface epithelium of villin-Cre PTEN^flox/flox mice. Conclusions: PTEN inactivation exerts a protective effect on the onset of colitis, and the transient and local down-modulation of PTEN might constitute an approach to drive recovery following acute intestinal inflammation. Full article

Background: Vitamin D is increasingly recognized not only for its role in skeletal development but also for its immunomodulatory and gastrointestinal effects. Maternal and neonatal vitamin D deficiency (VDD) has been associated with alterations in gut microbiota, impaired intestinal barrier integrity, and increased susceptibility to inflammatory conditions in neonates. However, the exact mechanisms linking perinatal vitamin D status to neonatal gastrointestinal morbidity remain incompletely understood. Methods: This review synthesizes current evidence (2015–2024) from clinical studies, animal models, and mechanistic research on the impact of VDD during pregnancy and the neonatal period on gastrointestinal health. Databases such as PubMed, Scopus, and Web of Science were systematically searched using keywords, including “vitamin D”, “neonate”, “gut microbiome”, “intestinal barrier”, and “necrotizing enterocolitis”. Results: Emerging data suggest that VDD in utero and postnatally correlates with dysbiosis, increased intestinal permeability, and elevated inflammatory responses in neonates. Notably, low 25(OH)D levels in mothers and newborns have been linked with a higher incidence of necrotizing enterocolitis (NEC), delayed gut maturation, and altered mucosal immunity. Vitamin D appears to modulate the expression of tight junction proteins, regulate antimicrobial peptides, and maintain microbial diversity through the vitamin D receptor (VDR). Conclusions: Understanding the gastrointestinal implications of early-life VDD opens a potential window for preventive strategies in neonatal care. Timely maternal supplementation and targeted neonatal interventions may mitigate gut-related morbidities and improve early-life health outcomes. Further longitudinal and interventional studies are warranted to clarify causality and optimal intervention timing. Full article

Topical percutaneous drug delivery has recently emerged as a novel strategy for the treatment of allergic diseases, offering targeted drug delivery to mucosal tissues adjacent to the skin. Unlike conventional topical approaches that act on the skin surface or mucosal membranes, topical percutaneous drug delivery enables non-invasive pharmacologic modulation of deeper structures such as the conjunctiva, nasal mucosa, and trachea. This review explores the rationale, pharmacokinetic foundation, clinical data, and future prospects of transdermal therapy in allergic conjunctivitis, allergic rhinitis, and asthma-related cough. In allergic conjunctivitis, eyelid-based transdermal delivery of antihistamines such as diphenhydramine and epinastine has shown rapid and long-lasting symptom relief, with epinastine cream recently approved in Japan following a randomized controlled trial (RCT) demonstrating its efficacy. Preclinical and clinical pharmacokinetic studies support the eyelid’s unique permeability and sustained drug release profile, reinforcing its utility as a delivery site for ocular therapies. In allergic rhinitis, diphenhydramine application to the nasal ala demonstrated symptomatic improvement in patients intolerant to intranasal therapies, though anatomical separation from the inflamed turbinates may limit consistent efficacy. Similarly, cervical tracheal application of steroids and antihistamines has shown potential benefit in asthma-related cough, especially for patients refractory to inhaled treatments, despite anatomical and depth-related limitations. Overall, site-specific anatomy, skin permeability, and disease localization are critical factors in determining therapeutic outcomes. While trans-eyelid therapy is supported by robust data, studies on the nasal ala and trachea remain limited to small-scale pilot trials. No major adverse events have been reported with nasal or tracheal application, but eyelid sensitivity requires formulation caution. To validate this promising modality, further RCTs, pharmacokinetic analyses, and formulation optimization are warranted. Topical percutaneous drug delivery holds potential as a non-invasive, site-directed alternative for managing allergic diseases beyond dermatologic indications. Full article

The COVID-19 pandemic has highlighted the complex interplay between the gut microbiota and systemic immune responses, particularly through the gut–lung axis. Disruptions in gut microbial diversity and function—commonly referred to as dysbiosis—have been increasingly implicated in the pathogenesis of SARS-CoV-2 infection. In this study, we assessed the gut bacteriome and permeability in SARS-CoV-2-infected patients using 16S sequencing and ELISA assays, respectively. We also measured blood inflammatory cytokines and fecal secretory IgA to evaluate systemic and mucosal immune responses. Significant alterations in both alpha and beta diversity metrics were observed in patients with COVID-19 (n = 79) and those with post-COVID-19 condition (n = 141) compared to the controls (n = 97). Differential abundance and taxonomic analyses revealed distinct microbial profiles in the infected groups. Increased plasma levels of IL-2, IL-6, IL-17A, IFN-γ, and zonulin were detected in patient samples. Some genera were elevated during acute infection, which was positively correlated with C-reactive protein, while Enterobacteriaceae and Escherichia-Shigella were associated with increased zonulin levels, indicating compromised intestinal barrier function. These findings suggest that gut dysbiosis may contribute to bacterial translocation and systemic inflammation. Overall, our results highlight the importance of the gut–lung axis and suggest that modulating the gut microbiota could support immune regulation in SARS-CoV-2 infection. Full article

Objectives: Ex vivo nasal mucosa models provide physiologically relevant platforms for evaluating nasal drug permeability; however, their application is often limited by high experimental variability and the absence of standardized methodologies. This study aimed to improve experimental design by addressing two major limitations: the confounding effects of mucosal thickness and the questionable reliability of fluorescein sodium (Flu-Na) as an integrity marker for chemically induced mucosal injury. Methods: Permeability experiments were conducted using porcine nasal tissues mounted in Franz diffusion cells, with melatonin and Flu-Na as model compounds. Tissues of varying thickness were collected from both intra- and inter-individual sources, and a numerical simulation-based method was employed to normalize apparent permeability coefficients (Papp) to a standardized mucosal thickness of 0.80 mm. The effects of thickness normalization and chemically induced damage were systematically evaluated. Results: Thickness normalization substantially reduced variability in melatonin Papp, particularly within same-animal comparisons, thereby improving statistical power and data reliability. In contrast, Flu-Na exhibited inconsistent correlations across different pigs and failed to reflect the expected increase in permeability following isopropyl alcohol (IPA)-induced epithelial damage. These results suggest that the relationship between epithelial injury and paracellular transport may be non-linear and not universally applicable under ex vivo conditions, limiting the suitability of Flu-Na as a standalone marker of mucosal integrity. Conclusions: The findings highlight the importance of integrating mucosal thickness correction into standardized experimental protocols and call for a critical reassessment of Flu-Na in nasal drug delivery research. Full article

The extensive research and studies conducted over the past decade have greatly improved our comprehension of the pathogenesis and risk factors associated with Spondyloarthritis (SpA). In addition, they have contributed to the advancement of novel therapeutic approaches. Although genetics still represents the primary risk factor for SpA, increasing evidence presented in this review suggests that environmental factors—such as air pollution, smoking, gut microbiota (GM), infections, and diet—also contribute to its pathogenesis. In detail, environmental particulate matters (PMs), which include ligands for the aryl hydrocarbon receptor—a cytosolic transcription factor responsive to toxic substances—facilitate the differentiation of T Helper 17 (Th17) cells, potentially exacerbating the autoinflammatory processes associated with SpA. Furthermore, smoking influences both the cellular and humoral aspects of the immune response, resulting in leukocytosis, impaired leukocyte functionality, and a decrease in various cytokines and soluble receptors, including interleukin (IL) 15, IL-1 receptor antagonist (IL-1Ra), IL-6, soluble IL-6 receptor (sIL-6R), as well as the vascular endothelial growth factor (VEGF) receptor. Studies have indicated that patients with SpA exhibit an increased prevalence of antibodies directed against a conserved epitope shared by the human leukocyte antigen B27 (HLA-B27)- and Klebsiella nitrogenase, in comparison to HLA-B27-positive controls. Additionally, current evidence regarding the GM suggests the presence of a gut–joint–skin axis, wherein the disruption of the mucosal barrier by specific bacterial species may enhance permeability to the gut-associated lymphoid tissue (GALT), resulting in localized inflammation mediated by Th1 and Th17 cells, as well as IL-17A. Finally, this review discusses the role of diet in shaping the microbial composition and its contribution to the pathogenesis of SpA. A comprehensive understanding of the mechanisms by which environmental factors influence the pathogenesis and progression of the disease could facilitate the development of novel personalized therapies targeting both external and internal environmental exposures, such as the gut microbial ecosystem. Full article

Background/Objectives: Metabolic dysfunction-associated steatohepatitis (MASH), characterized by liver inflammation, fibrosis, and fat accumulation, can develop into cirrhosis and liver cancer. Despite its increasing prevalence worldwide, there are few established therapies for advanced MASH. We previously demonstrated that stem cells from human exfoliated deciduous teeth-conditioned media (SHED-CM) exerted therapeutic effects in a MASH mouse model. The gut–liver axis is thought to be associated with liver disease progression, and soluble Siglec-9 (sSiglec-9), an immunoinhibitory receptor, is a key protein in SHED-CM that induces anti-inflammatory macrophages and has intestinal epithelial protective effects. Therefore, we evaluated sSiglec-9’s role in intestinal barrier protection in MASH mice. Methods: We evaluated sSiglec-9 effects on intestinal barrier function using in vitro Caco-2 cell monolayers injured by TNF-α and IFN-γ. For the MASH mouse model, male C57BL/6J mice were given a Western diet and high-sugar solution orally; to induce liver injury, CCl4 was intraperitoneally administered for 12 weeks. Mice were treated weekly with 10 ng/g sSiglec-9 or vehicle. Intestinal permeability was assessed by blood 4 kDa FITC-dextran concentration, and intestinal transcriptomes and liver histology were analyzed. Results: sSiglec-9 decreased intestinal permeability and liver inflammation in MASH mice. sSiglec-9 and SHED-CM reduced 4 kDa FITC-dextran permeability in injured Caco-2 cells, and sSiglec-9 significantly reduced intestinal permeability and modulated expression of 34 intestinal genes. The NAFLD Activity Score indicated significantly reduced inflammation following sSiglec-9 treatment. Conclusions: sSiglec-9 may protect intestinal barrier function by mitigating mucosal inflammation. sSiglec-9 treatment may represent a novel therapeutic approach for MASH via gut–liver axis modulation. Full article