Hypertension and chronic kidney disease (CKD) are closely linked conditions and represent common global health problems. Hypertension is a leading risk factor for cardiovascular disease, which is the main cause of mortality in CKD. Endothelial injury underlies the etiopathogenesis of both hypertension and CKD. The endothelial glycocalyx (eGC) is a dynamic, negatively charged, carbohydrate-rich layer that covers the luminal surface of endothelial cells. Its primary physiological function is to protect the endothelium, including the regulation of vascular permeability and homeostasis. Damage to the eGC, known as “shedding”, is an early predictor of endothelial dysfunction and is driven by oxidative stress and low-grade inflammation. In hypertension, loss of eGC integrity—often impaired by a high-salt diet—can reduce the bioavailability of nitric oxide (NO) and increase arterial stiffness. Similarly, in CKD, uremic toxicity, hypertension, and inflammation damage the eGC, resulting in increased permeability, albuminuria, and higher cardiovascular risk. This review summarizes current evidence and underscores the potential of eGC shedding markers, especially syndecan 1 (SDC-1) and hyaluronic acid (HA), as early predictors of vascular risk and disease progression in hypertension and CKD.

Background/Objectives: Endothelial activation by lipopolysaccharides (LPS) contributes to inflammation and the development of cardiovascular disease, making n-3 polyunsaturated fatty acids (PUFAs) potential modulators capable of mitigating endothelial dysfunction. The current study examines the effects of long-chain eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), along with their precursor, α-linolenic acid (ALA), on oxidative stress, adhesion molecule expression, and cytokine milieu in LPS-stimulated human aortic endothelial cells (HAECs). Methods: HAECs (fifth passage) were cultured in control medium under standard conditions: ~37 °C, 5% CO₂, ≥80% humidity. Cells were incubated in control basal cell medium or medium supplemented with ALA, EPA, DHA, and their combination (50 µM; n = 5 per group). After 48 h, cells were treated overnight (~16 h) with LPS from E. coli (0.75 and 1 µg/mL). HAECs and supernatants were collected for flow cytometry, Luminex, and ELISA assays. Significance was assessed using two-way analysis of variance ANOVA, followed by post hoc analyses (p < 0.05). Spearman’s correlation analysis was performed between markers, and p-values were adjusted using the Benjamini–Hochberg (BH) correction. Results: PUFA supplementation, particularly with DHA and ALA, significantly reduced intracellular reactive oxygen species (ROS) production and the expression of adhesion molecules (ICAM-1, E-selectin) in HAECs under both basal and LPS-stimulated inflammatory conditions. All PUFAs reduced pro-inflammatory cytokine levels (IFNγ, TNFα, IL-6), while ALA increased IL-1α and endoglin expression, indicating differential immunomodulatory effects. EPA exhibited antioxidant and anti-inflammatory effects primarily at higher LPS concentrations. Correlation analysis demonstrated strong interdependence between oxidative stress, inflammatory markers, and vascular activation, further confirming PUFA-mediated endothelial protection. Conclusions: PUFA supplementation produced molecule-specific effects on endothelial inflammation. DHA and ALA consistently showed anti-inflammatory and antioxidative effects, while EPA’s beneficial effect was more pronounced under inflammatory conditions, emphasising the importance of PUFA type and context in managing vascular inflammation.