Sex, Endothelial Cell Functions, and Peripheral Artery Disease

Exploring the therapeutic potential of beetroot juice in patients with peripheral artery disease: A Narrative review

Peripheral artery disease (PAD) is a circulatory disorder caused by atherosclerosis, leading to the narrowing or blockage of peripheral arteries, often affecting the arteries in the lower limbs. This condition can result in intermittent claudication and severe limb ischemia, significantly reducing patients' quality of life. In recent years, increasing evidence suggests that dietary interventions play a crucial role in the prevention and management of PAD, offering a safe and non-invasive treatment option. Beetroot, a natural root vegetable, demonstrates significant health benefits through its various bioactive compounds. It is rich in nitrate and betaine, which are metabolized in the body via the nitrate-nitrite- nitric oxide (NO) pathway, increasing the bioavailability of NO. NO is an important vasodilator that can improve blood flow and lower blood pressure. Additionally, the active compounds in beetroot may further enhance its health effects by altering the activity of the oral microbiome. This review explores the potential therapeutic effects of beetroot juice (BRJ) in the management of PAD. The findings indicate that BRJ can improve exercise performance, lower blood pressure, improve endothelial function, enhance skeletal muscle microvascular function and central autonomic nervous system function. Based on these findings, beetroot and its rich bioactive compounds hold promise as a novel supportive therapy for improving PAD.

Reconstituted High-Density Lipoproteins Rescue Diabetes-Impaired Endothelial Cell Metabolic Reprograming and Angiogenic Responses to Hypoxia

BACKGROUND

Impaired angiogenic responses to ischemia underlie diabetic vascular complications. Reconstituted high-density lipoproteins (rHDLs) have proangiogenic effects in diabetes. The PDK4 (pyruvate dehydrogenase kinase 4)/PDC (pyruvate dehydrogenase complex) axis is an oxygen-conserving mechanism that preserves endothelial cell function in hypoxia. We aimed to determine the role of the PDK4/PDC axis in angiogenesis, the effect of diabetes on its regulation in response to ischemia, and the proangiogenic properties of rHDL.

METHODS

Expression of PDK4 and phosphorylated PDC (pPDC) were measured in PBS- or rHDL-treated wounds of nondiabetic and streptozotocin-induced diabetic mice and PBS- or rHDL-treated endothelial cells exposed to glucose and hypoxia. The importance of PDK4 in the action of rHDL was determined by siRNA knockdown in vitro and PDK4 inhibitor in vivo. Chromatin immunoprecipitation assay was performed to identify the mechanism for PDK4 induction by rHDL.

RESULTS

PDK4 and pPDC were elevated early (24 hours) post-induction of wound ischemia in nondiabetic wounds, which did not occur in diabetic mice. Topical rHDL rescued this impairment, enhancing PDK4 (68%; P=0.0041) and pPDC (165%; P=0.029) in diabetic wounds. Wound neovascularization (62%; P<0.05) and closure (154%; P<0.001) were increased in diabetic rHDL-treated wounds. In vitro, PDK4 and pPDC levels were increased with hypoxia (65%, P=0.043 and 64%, P=0.026, respectively). High glucose did not elicit a further stepwise induction in PDK4/pPDC, with aberrant increases in mitochondrial respiration (19%; P=0.026), and impaired angiogenic functions. Importantly, rHDL increased PDK4 and pPDC 2-fold, returning mitochondrial respiration and angiogenic functions to normal glucose levels. PDK4 inhibition ameliorated the proangiogenic effects of rHDL. rHDL increased FOXO1 (forkhead box O1) binding to the PDK4 promoter and suppressed FOXO1 phosphorylation, presenting FOXO1 as a mechanism for rHDL-mediated induction of PDK4.

CONCLUSIONS

The PDK4/PDC axis response to ischemia is impaired in diabetes and is important for the proangiogenic effects of rHDL.

Causal association between circulating inflammatory proteins and peripheral artery disease: a bidirectional two-sample Mendelian randomization study

Introduction

A growing body of research has shown a strong connection between circulating inflammatory proteins and Peripheral artery disease (PAD). However, the causal relationship between circulating inflammatory proteins and PAD is still not fully understood. To investigate this association, we conducted a bidirectional Mendelian randomization study.

Materials and methods

Our study utilized genetic variation data obtained from genome-wide association studies (GWAS) datasets. Specifically, the GWAS dataset related to PAD (identifier: finn-b-I9_PAD) included 7,098 cases and 206,541 controls. Additionally, we extracted data on 91 inflammatory proteins from another GWAS dataset (identifiers: GCST90274758-GCST90274848), involving 14,824 participants. To assess the causal relationship between circulating inflammatory proteins and PAD development, we employed methodologies such as inverse variance weighting (IVW), MR Egger regression, and the weighted median approach. Furthermore, sensitivity analyses were conducted to ensure the reliability and robustness of our findings.

Results

Two inflammatory proteins were found to be significantly associated with PAD risk: Natural killer cell receptor 2B4 levels (OR, 1.219; 95% CI,1.019~1.457; P=0.03), Fractalkine levels (OR, 0.755; 95% CI=0.591~0.965; P=0.025). PAD had statistically significant effects on 12 inflammatory proteins: C-C motif chemokine 19 levels (OR, 0.714; 95% CI, 0.585 to 0.872; P=0.001), T-cell surface glycoprotein CD5 levels (OR, 0.818; 95% CI, 0.713 to 0.938; P=0.004), CUB domain-containing protein 1 levels (OR, 0.889; 95% CI, 0.809 to 0.977; P=0.015), Fibroblast growth factor 23 levels (OR, 1.129; 95% CI, 1.009 to 1.264; P=0.034), Interferon gamma levels (OR, 1.124; 95% CI, (1.011 to 1.250); P=0.031),Interleukin-15 receptor subunit alpha levels (OR, 1.183; 95% CI,(1.005 to 1.392); P=0.044), Interleukin-17C levels (OR,1.186; 95% CI, (1.048 to 1.342); P=0.007), Interleukin-1-alpha levels (OR, 1.349; 95% CI, (1.032 to 1.765); P=0.029), Interleukin-5 levels (OR, 1.119; 95% CI,(1.003 to 1.248); P=0.043), Latency-associated peptide transforming growth factor beta 1 levels (OR,1.123; 95% CI, (1.020 to 1.236); P=0.018), Matrix metalloproteinase-10 levels (OR, 1.119; 95% CI,(1.015 to 1.233); P=0.024), Signaling lymphocytic activation molecule levels (OR, 0.823; 95% CI, (0.693 to 0.978); P=0.027).

Conclusion

Our research expands on genetic studies exploring the strong association between circulating inflammatory proteins and PAD. This discovery has the potential to inform and shape future clinical and basic research endeavors in this area.

A Non-Coronary, Peripheral Arterial Atherosclerotic Disease (Carotid, Renal, Lower Limb) in Elderly Patients-A Review PART II-Pharmacological Approach for Management of Elderly Patients with Peripheral Atherosclerotic Lesions outside Coronary Territory

BACKGROUND

Aging is a key risk factor for atherosclerosis progression that is associated with increased incidence of ischemic events in supplied organs, including stroke, coronary events, limb ischemia, or renal failure. Cardiovascular disease is the leading cause of death and major disability in adults ≥ 75 years of age. Atherosclerotic occlusive disease affects everyday activity, quality of life, and it is associated with reduced life expectancy. As most multicenter randomized trials exclude elderly and very elderly patients, particularly those with severe comorbidities, physical or cognitive dysfunctions, frailty, or residence in a nursing home, there is insufficient data on the management of older patients presenting with atherosclerotic lesions outside coronary territory. This results in serious critical gaps in knowledge and a lack of guidance on the appropriate medical treatment. In addition, due to a variety of severe comorbidities in the elderly, the average daily number of pills taken by octogenarians exceeds nine. Polypharmacy frequently results in drug therapy problems related to interactions, drug toxicity, falls with injury, delirium, and non-adherence. Therefore, we have attempted to gather data on the medical treatment in patients with extra-cardiac atherosclerotic lesions indicating where there is some evidence of the management in elderly patients and where there are gaps in evidence-based medicine. Public PubMed databases were searched to review existing evidence on the effectiveness of lipid-lowering, antithrombotic, and new glucose-lowering medications in patients with extra-cardiac atherosclerotic occlusive disease.

A Non-Coronary, Peripheral Arterial Atherosclerotic Disease (Carotid, Renal, Lower Limb) in Elderly Patients-A Review: Part I-Epidemiology, Risk Factors, and Atherosclerosis-Related Diversities in Elderly Patients

Atherosclerosis is a generalized and progressive disease. Ageing is a key risk factor for atherosclerosis progression that is associated with the increased incidence of ischemic events in supplied organs, including stroke, coronary events, limb ischemia, or renal failure. Cardiovascular disease is the leading cause of death and major disability in adults ≥ 75 years of age. Atherosclerotic occlusive disease affects everyday activity and quality of life, and it is associated with reduced life expectancy. Although there is evidence on coronary artery disease management in the elderly, there is insufficient data on the management in older patients presented with atherosclerotic lesions outside the coronary territory. Despite this, trials and observational studies systematically exclude older patients, particularly those with severe comorbidities, physical or cognitive dysfunctions, frailty, or residence in a nursing home. This results in serious critical gaps in knowledge and a lack of guidance on the appropriate medical treatment and referral for endovascular or surgical interventions. Therefore, we attempted to gather data on the prevalence, risk factors, and management strategies in patients with extra-coronary atherosclerotic lesions.