Astaxanthin-loaded alginate-chitosan gel beads activate Nrf2 and pro-apoptotic signalling pathways against oxidative stress

Oxidative stress (OS) plays a crucial role in disease development. Astaxanthin (ATX), a valuable natural compound, may reduce OS and serve as a treatment for diseases like neurodegenerative disorders and cancer. Nuclear factor-erythroid 2-related factor 2 (Nrf2) regulates antioxidant enzymes and OS management. We evaluated ATX's antioxidant activity via Alg-CS/ATX gel beads in vitro. ATX-encapsulated alginate-chitosan (Alg-CS/ATX) gel beads were synthesized and structurally/morphologically characterized by SEM, FT-IR, and XRD. Their biological effects were examined in human umbilical vein endothelial cells (HUVECs) treated with H2O2 through MTT assay, Annexin V/PI, cell cycle studies, and western blotting. Alg-CS effectively carried ATX, with high capacity and reduced pore size. Alg-CS/ATX displayed an 84% encapsulation efficiency, maintaining stability for 30 days. In vitro studies showed a 1.4-fold faster release at pH 5.4 than at neutral pH, improving ATX's therapeutic potential. HUVECs treated with Alg-CS/ATX showed enhanced viability via increased Nrf2 expression. Alg-CS gel beads exhibit significant potential as a biocompatible vehicle for delivering ATX to combat OS with considerable opportunity for clinical applications.

Using physicochemical and biological parameters for the evaluation of water quality and environmental conditions in international wetlands on the southern part of Lake Urmia, Iran

The Kani Barazan and Yadegarlou wetlands in the southern part of Lake Urmia (Iran) have been substantially modified due to human activities and anthropogenic use. In recent years, freshwater-based eco-biological studies to recognize the quality of water resources have been greatly expanded. Microalgae and Cyanophyta are considered important bioindicators for the evaluation of water quality and wetland health worldwide. Herein, 22 microalgae and 5 Cyanophyta genera were identified in both wetlands, in which Cyanophyta has mainly caused blooms. Principal components analysis (PCA) was carried out based on links between the distribution of microalgae and Cyanophyta with physical and chemical parameters. The data showed that depth, turbidity, and the temperature had a significant influence on the microalga and Cyanophyta communities in both wetlands. Based on the biological properties, it seems that the Kani Barazan and Yadegarlou international wetlands experience meso-eutrophic conditions. The integration of the physical, chemical and biological parameters with the water quality index (WQI) revealed that both wetlands were polluted as a consequence of human activities. Moreover, a close relationship between WQI and the biological parameters was documented. Thus, we concluded that microalgae and Cyanophyta communities, their abundance patterns, and water quality changes could provide valuable data for the conservation of the Kani Barazan and Yadegarlou international wetlands.

Impacts of oxidants and antioxidants on the emergence and progression of Alzheimer's disease

The brain shows a high sensitivity to oxidative stress (OS). Thus, the maintenance of homeostasis of the brain regarding the reduction-oxidation (redox) situation is crucial for the regular function of the central nervous systems (CNS). The imbalance between the reactive oxygen species (ROS) and the cellular mechanism might lead to the emergence of OS, causing profound cell death as well as tissue damages and initiating neurodegenerative disorders (NDDs). Characterized by the cytoplasmic growth of neurofibrillary tangles and extracellular β-amyloid plaques, Alzheimer's disease (AD) is a complex NDD that causes dementia in adult life with severe manifestations. Nuclear factor erythroid 2-related factor 2 (NRF2) is a key transcription factor that regulates the functional expression of OS-related genes and the functionality of endogenous antioxidants. In the case of oxidative damage, NRF2 is transferred to the nucleus and attached to the antioxidant response element (ARE) that enhances the sequence to initiate transcription of the cell-protecting genes. This review articulates various mechanisms engaged with the generation of active and reactive species of endogenous and exogenous oxidants and focuses on the antioxidants as a body defense system regarding the NRF2-ARE signaling path in the CNS.