Human Vein Endothelial Cells

PPAP with Protective Effect on Human Vein Endothelial Cells Injured by High-Glucose

Originating from Hypericum acmosepalum, polycyclic polyprenylated acylphloroglucinol (PPAP) are highly oxygenated compounds with significant pharmacological effects, such as anti-inflammatory and antioxidant activities. These compounds, crucial for treating endothelial damage due to hyperglycemia in diabetes.

To explore the potential against high glucose injury compounds from H. acmosepalum, the EtOH extract of the aerial parts of H. acmosepalum was fractionated chromategraphically to yield sixteen PPAPs (1–16). Then, a bioassay assessed the protective effects of isolated PPAPs on human umbilical vein endothelial cells (HUVECs) damaged by high glucose. Initially, the cytotoxicity of compounds 1–4, and 7–16 was measured using the CCK-8 assay, with hyperacmotone C showing cytotoxicity at an IC₅₀ of 12.9 μg/mL. The compounds' protective effects at 50 μg/mL were further evaluated using the CCK-8 assay (Fig. 1). For compounds with activity surpassing aspirin by 33.0%, six concentration gradients were tested to find the EC₅₀. Compound 13 displayed a promising EC₅₀ of 4.1 μg/mL, indicating significant protection of HUVECs. Its cell viability surpassed the high-glucose injured model group, suggesting repair capabilities. Additionally, a β-galactosidase assay showed that compound 13 reduced cell senescence, as evidenced by decreased positive staining (Fig. 2). These results highlight compound 13's potential anti-hyperglycemia effect.

Fig. 1. Screening results of protective effect of compounds 1–4, and 7–16 at 50 μg/mL on HUVECs injured by high-glucose (Wang A, Han H, et al., 2023).

Fig. 2. The HUVECs morphologies of Control (A), Model (B), Positive Control (C), and sample groups at 1 (D), 5 (E), 50 (F) μg/mL of compound 13 (Wang A, Han H, et al., 2023).

ALA Improves the Viability of H₂O₂-Induced HUVECs and Reduces LDH Release

Atherosclerosis arises from oxidative stress and inflammatory processes affecting vascular endothelial cells. ROS-mediated apoptosis and inflammatory responses are key contributors. Alpha-lipoic acid (ALA), a potent antioxidant, may mitigate these effects. Wang et al. utilized an H₂O₂-induced human umbilical vein endothelial cells (HUVECs) injury model to evaluate ALA's protective mechanism by administering ALA with various concentrations.

The selected experimental concentrations for the low, medium and high-dose ALA groups were 100, 200 and 400 μmol/L, respectively. After incubating HUVECs with 250 μmol/L H₂O₂ and varying ALA concentrations for 48 hours, an MTT assay evaluated cell viability. Figure 3(b) shows that the cell survival rate of the H₂O₂ injury group significantly dropped compared to the control. ALA co-incubation increased survival rates to 57.09%, 68.17%, and 78.10%, with significant differences among doses, confirming ALA's protective effect (Fig. 3b). LDH is considered to be a biomarker for assessing cellular injury. As expected, the model group exhibited higher LDH activity than controls. ALA reduced LDH release in a dose-dependent manner (Fig. 4).

Fig. 3. Effects of H₂O₂ and ALA on HUVECs cell viability (Wang W, An L, et al., 2020).

Fig. 4. Effects of different concentrations of ALA on the LDH activity in H₂O₂-induced HUVECs (Wang W, An L, et al., 2020).