Chrysin-based supramolecular cyclodextrin-calixarene drug delivery system: a novel approach for attenuating cardiac fibrosis in chronic diabetes

Blockade of P2X7 receptors preserves blood retinal barrier integrity by modulating the plasmalemma vesicle-associated protein: Implications for diabetic retinopathy

BACKGROUND AND PURPOSE

Plasmalemma vesicle-associated protein (PLVAP) regulates transcytosis in vascular endothelial cells. PLVAP expression is increased in pathological conditions, such as diabetic retinopathy. P2X7 receptor antagonists have been shown to preserve blood-retinal barrier (BRB) integrity. Here, we have tested the hypothesis that PLVAP expression is tightly linked to P2X7 receptor activity, leading to breakdown of the BRB in an in vitro model of diabetic retinopathy.

EXPERIMENTAL APPROACH

We integrated network approaches with an in vitro model of diabetic retinopathy using primary human retinal microvascular endothelial cells (HRMECs). Cells were treated with a P2X7 receptor antagonist, JNJ47965567, and expression of several genes predicted to belong to the P2X7 receptor signalling network were assessed. Levels and localisation of PLVAP, VE-cadherin and zonula occludens-1 (ZO-1) in HRMECs were evaluated. In vivo, the effects of JNJ47965567 on PLVAP expression in the retinas of diabetic mice were assessed.

KEY RESULTS

High levels of glucose increased PLVAP expression in HRMECs, which was blocked by JNJ47965567. Furthermore, JNJ47965567 preserved VE-cadherin and ZO-1. In the choroidal vasculature of diabetic mice, PLVAP immunostaining was increased, compared to levels in non-diabetic mice. This increase was significantly attenuated by treatment with JNJ47965567 CONCLUSIONS AND IMPLICATIONS: This study showed that P2X7 receptor signalling is an important component of a complex gene regulatory network, including PLVAP, mediating the pathophysiology of diabetic retinopathy. The P2X7 receptor antagonist JNJ47965567 showed a good pharmacodynamic profile, suggesting that this approach could be of value in the treatment of diabetic retinopathy.

Astaxanthin protects fludrocortisone acetate-induced cardiac injury by attenuating oxidative stress, fibrosis, and inflammation through TGF-β/Smad signaling pathway

Hypertensive rats serve as a good experimental model for studying the pathophysiology of cardiac hypertrophy and remodeling leading to heart failure. In this study, we aimed to analyze the effect of astaxanthin and possible mechanisms involved in alleviating oxidative stress, fibrosis and inflammation that triggers cardiac remodeling using male uninephrectomized Long Evans rats. Cardiac hypertrophy and hypertension were induced in rats termed as 'FCA-Salt rats' by an oral administration of fludrocortisone acetate (FCA) and 1 % NaCl in drinking water. Biochemical assays showed that FCA-Salt rats exhibited an upregulation of oxidative stress markers AOPP, MDA and downregulation of NO in heart and kidney, which was reversed by astaxanthin treatment. Astaxanthin further regularized the reduced activities of antioxidant enzymes GSH, SOD and CAT in these tissues. ELISA revealed that astaxanthin significantly reduced the inflammatory response by reducing the elevated levels of IL-1β, IL-17a, and TNF-α and pro-fibrotic marker TGF-β1 in plasma. Real-time qPCR depicted an upregulation of TNF-α, IL-1β, IL-6, IL-17A as well as signaling molecules TGF-β1, Smad2 and Smad3 in heart of FCA-Salt rats, which was reduced significantly by astaxanthin. Sirius red staining showed that the cardiac and renal fibrosis was significantly improved by astaxanthin treatment. Together, our results suggest that astaxanthin treatment is beneficial in protecting cardio-renal damage in hypertension through TGF-β/Smad signaling pathway, hence, this molecule may be considered for the maintenance of cardio-renal health.

Chrysin-loaded calixarene-cyclodextrin ternary drug delivery system inhibits TGF-β and galectin-1 mediated pathways in diabetic liver fibrosis

This study investigated the efficacy of a new chrysin-loaded calixarene-cyclodextrin ternary drug delivery system (DDS) in reversing liver fibrosis in a mouse model of chronic diabetes. The system was designed to enhance the solubility and bioavailability of chrysin (CHR) and calixarene 0118 (OTX008). Adult male CD1 mice received streptozotocin (STZ) injections to induce diabetes. After 20 weeks, they underwent intraperitoneal treatments twice weekly for a two-week period. Histological analyses revealed that long-term hyperglycaemia increased liver fibrosis and altered hepatic ultrastructure, characterized by lipid accumulation, hepatic stellate cell activation, and collagen deposition. The treatment with the chrysin-loaded DDS restored liver structure closely to normal levels, as opposed to the minimal impact observed with sulfobutylated β-cyclodextrin (SBECD) alone. The treatment significantly decreased serum activities of alanine /aspartate transaminases and reduced the gene expression of collagen type I (Col-I). It also modulated the transforming growth factor beta 1 (TGF-β1)/Smad signalling pathway, inhibiting the activation and proliferation of hepatic stellate cells. The treatment led to a downregulation of the TGF-β1 gene and its receptors TGFβR1 and TGFβR2, together with a decrease in Smad 2 and 3 mRNA levels. Conversely, Smad 7 mRNA expression was increased by the DDS. Furthermore, it downregulated galectin-1 (Gal-1) gene and protein levels, which correlated with fibrotic markers. In conclusion, the chrysin-loaded calixarene-cyclodextrin ternary DDS presents a promising therapeutic approach for diabetic liver fibrosis, effectively targeting fibrotic pathways and restoring hepatic function and structure.

Ginsenoside Rb1 reduces oxidative/carbonyl stress damage and dysfunction of RyR2 in the heart of streptozotocin-induced diabetic rats

BACKGROUND

Oxidative stress may contribute to cardiac ryanodine receptor (RyR2) dysfunction in diabetic cardiomyopathy. Ginsenoside Rb1 (Rb1) is a major pharmacologically active component of ginseng to treat cardiovascular diseases. Whether Rb1 treat diabetes injured heart remains unknown. This study was to investigate the effect of Rb1 on diabetes injured cardiac muscle tissue and to further investigate its possible molecular pharmacology mechanisms.

METHODS

Male Sprague-Dawley rats were injected streptozotocin solution for 2 weeks, followed 6 weeks Rb1 or insulin treatment. The activity of SOD, CAT, Gpx, and the levels of MDA was measured; histological and ultrastructure analyses, RyR2 activity and phosphorylated RyR2(Ser2808) protein expression analyses; and Tunel assay were performed.

RESULTS

There was decreased activity of SOD, CAT, Gpx and increased levels of MDA in the diabetic group from control. Rb1 treatment increased activity of SOD, CAT, Gpx and decreased the levels of MDA as compared with diabetic rats. Neutralizing the RyR2 activity significantly decreased in diabetes from control, and increased in Rb1 treatment group from diabetic group. The expression of phosphorylation of RyR2 Ser2808 was increased in diabetic rats from control, and were attenuated with insulin and Rb1 treatment. Diabetes increased the apoptosis rate, and Rb1 treatment decreased the apoptosis rate. Rb1 and insulin ameliorated myocardial injury in diabetic rats.

CONCLUSIONS

These data indicate that Rb1 could be useful for mitigating oxidative damage, reduced phosphorylation of RyR2 Ser2808 and decreased the apoptosis rate of cardiomyocytes in diabetic cardiomyopathy.

Chrysin Directing an Enhanced Solubility through the Formation of a Supramolecular Cyclodextrin-Calixarene Drug Delivery System: A Potential Strategy in Antifibrotic Diabetes Therapeutics

Calixarene 0118 (OTX008) and chrysin (CHR) are promising molecules for the treatment of fibrosis and diabetes complications but require an effective delivery system to overcome their low solubility and bioavailability. Sulfobutylated β-cyclodextrin (SBECD) was evaluated for its ability to increase the solubility of CHR by forming a ternary complex with OTX008. The resulting increase in solubility and the mechanisms of complex formation were identified through phase-solubility studies, while dynamic light-scattering assessed the molecular associations within the CHR-OTX008-SBECD system. Nuclear magnetic resonance, differential scanning calorimetry, and computational studies elucidated the interactions at the molecular level, and cellular assays confirmed the system's biocompatibility. Combining SBECD with OTX008 enhances CHR solubility more than using SBECD alone by forming water-soluble molecular associates in a ternary complex. This aids in the solubilization and delivery of CHR and OTX008. Structural investigations revealed non-covalent interactions essential to complex formation, which showed no cytotoxicity in hyperglycemic in vitro conditions. A new ternary complex has been formulated to deliver promising antifibrotic agents for diabetic complications, featuring OTX008 as a key structural and pharmacological component.