Vitamin D deficiency enhances vascular oxidative stress, inflammation, and angiotensin II levels in the microcirculation of diabetic patients

Unveiling the Interplay-Vitamin D and ACE-2 Molecular Interactions in Mitigating Complications and Deaths from SARS-CoV-2

The interaction of the SARS-CoV-2 spike protein with membrane-bound angiotensin-converting enzyme-2 (ACE-2) receptors in epithelial cells facilitates viral entry into human cells. Despite this, ACE-2 exerts significant protective effects against coronaviruses by neutralizing viruses in circulation and mitigating inflammation. While SARS-CoV-2 reduces ACE-2 expression, vitamin D increases it, counteracting the virus's harmful effects. Vitamin D's beneficial actions are mediated through complex molecular mechanisms involving innate and adaptive immune systems. Meanwhile, vitamin D status [25(OH)D concentration] is inversely correlated with severity, complications, and mortality rates from COVID-19. This study explores mechanisms through which vitamin D inhibits SARS-CoV-2 replication, including the suppression of transcription enzymes, reduced inflammation and oxidative stress, and increased expression of neutralizing antibodies and antimicrobial peptides. Both hypovitaminosis D and SARS-CoV-2 elevate renin levels, the rate-limiting step in the renin-angiotensin-aldosterone system (RAS); it increases ACE-1 but reduces ACE-2 expression. This imbalance leads to elevated levels of the pro-inflammatory, pro-coagulatory, and vasoconstricting peptide angiotensin-II (Ang-II), leading to widespread inflammation. It also causes increased membrane permeability, allowing fluid and viruses to infiltrate soft tissues, lungs, and the vascular system. In contrast, sufficient vitamin D levels suppress renin expression, reducing RAS activity, lowering ACE-1, and increasing ACE-2 levels. ACE-2 cleaves Ang-II to generate Ang(1-7), a vasodilatory, anti-inflammatory, and anti-thrombotic peptide that mitigates oxidative stress and counteracts the harmful effects of SARS-CoV-2. Excess ACE-2 molecules spill into the bloodstream as soluble receptors, neutralizing and facilitating the destruction of the virus. These combined mechanisms reduce viral replication, load, and spread. Hence, vitamin D facilitates rapid recovery and minimizes transmission to others. Overall, vitamin D enhances the immune response and counteracts the pathological effects of SARS-CoV-2. Additionally, data suggests that widely used anti-hypertensive agents-angiotensin receptor blockers and ACE inhibitors-may lessen the adverse impacts of SARS-CoV-2, although they are less potent than vitamin D.

Tibial transverse transport combined with platelet-rich plasma sustained-release microspheres activates the VEGFA/VEGFR2 pathway to promote microcirculatory reconstruction in diabetic foot ulcer

This study proposes to investigate the therapeutic efficacy and mechanism of combining tibial transverse transport (TTT) with platelet-rich plasma (PRP) for diabetic foot ulcer (DFU). The diabetic rabbit model was constructed with Streptozotocin, which was intervened with TTT and PRP. PRP injection combined with TTT significantly promoted vascularisation and enhanced CD31, VEGFA, and VEGFR2 expressions compared to traditional TTT. However, the VEGFR2 inhibitor suppressed these phenomena. In the in vitro injury model, PRP reversed the diminished human umbilical vein endothelial cells (HUVECs) function and vascularisation caused by high-glucose damage. Additionally, PRP reduced inflammation and oxidative stress (approximately 47% ROS level) and enhanced VEGFA and VEGFR2 expression in HUVECs. However, the knockdown of VEGFR2 reversed the effect of PRP. In conclusion, TTT combined with intraosseous flap injection of PRP sustained-release microspheres activated the VEGFA/VEGFR2 pathway to promote microcirculatory reconstruction in DFU. These findings may provide new potential therapeutic strategies for DFU.

Long-Term Effects of Microfiltered Seawater and Resistance Training with Elastic Bands on Hepatic Parameters, Inflammation, Oxidative Stress, and Blood Pressure of Older Women: A 32-Week, Double-Blinded, Randomized, Placebo-Controlled Trial

The bulk of research on microfiltered seawater (SW) is based on its short-term effects. However, the long-term physiological adaptations to combining SW and resistance training (RT) are unknown. This study aimed to analyse the impact of an RT program using elastic bands combined with SW intake on hepatic biomarkers, inflammation, oxidative stress, and blood pressure in post-menopausal women. Ninety-three women voluntarily participated (age: 70 ± 6.26 years; body mass index: 22.05 ± 3.20 kg/m2; Up-and-Go Test: 6.66 ± 1.01 s). RT consisted of six exercises (32 weeks, 2 days/week). Nonsignificant differences were reported for hepatic biomarkers except for a reduction in glutamic-pyruvic transaminase (GPT) in both RT groups (RT + SW: p = 0.003, ES = 0.51; RT + Placebo: p = 0.012, ES = 0.36). Concerning oxidative stress, vitamin D increased significantly in RT + SW (p = 0.008, ES = 0.25). Regarding inflammation, interleukin 6 significantly decreased (p = 0.003, ES = 0.69) in RT + SW. Finally, systolic blood pressure significantly decreased in both RT groups (RT + placebo: p < 0.001, ES = 0.79; RT + SW: p < 0.001, ES = 0.71) as did diastolic blood pressure in both SW groups (RT + SW: p = 0.002, ES = 0.51; CON + SW: p = 0.028, ES = 0.50). Therefore, RT + SW or SW alone are safe strategies in the long term with no influences on hepatic and oxidative stress biomarkers. Additionally, SW in combination with RT positively influences vitamin D levels, inflammation, and blood pressure in older women.