Gifu Pharmaceutical University

Endothelial glycocalyx (eGCX) is shed into the bloodstream during reperfusion injury and ischemia, and its core proteins, syndecan-1 and glypican-1, can be measured in the blood. However, no studies have measured cardiac serum syndecan-1 concentrations in blood from the coronary sinus. Therefore, we aimed to examine the relationship between the degree and changes in eGCX damage and postoperative clinical outcomes using blood drawn from the coronary sinus.

Serum eGCX concentrations in the coronary sinus of 56 patients who underwent cardiac and thoracic aortic surgery with combined ante- and retrograde cardioplegia were analyzed. The association between maximum postoperative troponin T (TnT) level, as a myocardial damage marker, and eGCX injury markers, including syndecan-1 and glypican-1, measured in coronary sinus blood drawn immediately after reperfusion, was assessed. The association between eGCX injury markers and duration of cardioplegic arrest was also investigated.

An association between degree of change in coronary sinus serum syndecan-1 concentration during reperfusion and postoperative maximum serum TnT levels was observed. No such association was found between the degree of change in coronary sinus serum glypican-1 concentration during reperfusion and postoperative serum TnT levels. Similar results were obtained for somatic circulation. Moreover, an association between maximum change in serum syndecan-1 concentration in the coronary sinus during reperfusion and cardioplegic arrest duration was observed. No such association was found for glypican-1 concentration.

The degree of endothelial damage to the coronary sinuses during reperfusion may predict myocardial injury following cardiac surgery.

Topical application is the preferred route for drugs to treat ocular diseases, but most current eye drop preparations deliver active ingredients only transiently to surface structures. To enhance ocular drug delivery following topical application, we developed a preparation utilizing the unique property of polyvinyl alcohol (PVA) nanofibers to gel rapidly upon contact with minimal tear fluid on the ocular surface, thereby enhancing precorneal residence time. Coumarin 6 (C6), a poorly water-soluble fluorescent compound, was used as a tracer to evaluate the intraocular drug delivery by several PVA- and non-PVA-based preparations. C6 was incorporated into nanofibers via emulsion electrospinning and maintained in an amorphous state within the fibers to enhance solubility. Nanofibers were prepared using PVA with different polymerization and hydrolysis degrees. The corneal epithelial cell (CEC) damage potential was examined in monolayer culture by electrical resistance measures. All preparations demonstrated good biocompatibility without CEC barrier damage. The C6 release profiles varied depending on polymerization and hydrolysis degrees of PVA, indicating tunable release capacity. Low-polymerization PVA resulted in rapid C6 release, whereas completely hydrolyzed PVA enabled sustained release. C6 was barely detectable in mouse ocular tissue after topical administration of an aqueous suspension, while C6 dissolved in ethanol or encapsulated in liposomes reached peak ocular concentrations within 30 min, followed by a decline at 6 h. In contrast, administration of C6-containing nanofiber mats resulted in 5- to 18-fold higher retinal concentrations at 6 h compared to C6-containing liposomes. This PVA nanofiber-based system can safely prolong ocular drug delivery and improve bioavailability for poorly water-soluble compounds.

Short-chain fatty acids (SCFAs), such as acetic, propionic, and butyric acid, are important biomarkers that reflect gut microbiota composition, disease progression, and overall health. Conventional SCFA analysis typically involves derivatization prior to liquid or gas chromatography. However, derivatization is challenging due to the volatility of SCFAs and interference from similar carboxylic acids in biological samples and often requires complex purification steps. Consequently, the development of derivatization-free liquid chromatography-mass spectrometry (LC-MS) methods is desirable, although direct LC-MS analysis of intact SCFAs often suffers from limited sensitivity and accuracy. In this study, we have developed a derivatization-free LC-MS method for the analysis of major SCFAs (C2-C4) in the cecum content and feces of mice. Separation was performed using a mixed-mode column combining hydrophilic interaction chromatography and anion-exchange chromatography. We found that ammonium formate, required for separation, significantly suppressed SCFA signal intensity, whereas its replacement by ammonium fluoride prevented this suppression. Furthermore, we have demonstrated that the background noise in biological sample analysis can be reduced by selective reaction monitoring (SRM) mode, in which the same m/z value was set for both the precursor and product ions, as compared with selective ion monitoring (SIM) mode. The method developed in this study showed good validation values and sensitivity in the quantification of targeted SCFAs in mouse biological samples, demonstrating the excellent practicability of this method and making it a useful tool for research on the gut microbiome.