Medial Arterial Calcification: An Overlooked Player in Peripheral Arterial Disease

The associations between functional vitamin K status and all-cause mortality, cardiovascular disease and end-stage kidney disease in persons with type 1 diabetes

BACKGROUND AND AIM

Vitamin K deficiency is common in persons with kidney disease, which is a known complication of diabetes. We aimed to assess the association of vitamin K status as reflected by plasma dephosphorylated-uncarboxylated matrix Gla protein (dp-ucMGP) with mortality, cardiovascular disease (CVD) and progression to end-stage kidney disease (ESKD) in persons with type 1 diabetes.

MATERIALS AND METHODS

We analysed plasma dp-ucMGP in stored baseline samples from a cohort of 667 persons with type 1 diabetes (baseline visit: 2009-2011). Information on mortality and CVD was obtained through linkage to registers. Cox-proportional hazards models were applied to estimate hazard ratios (HRs) of mortality, CVD and ESKD per one doubling of dp-ucMGP.

RESULTS

A total of 53 deaths were recorded during follow-up. Persons with higher dp-ucMGP (reflecting lower vitamin K status) had higher mortality in the unadjusted model (HR: 2.06 [95% confidence interval-CI: 1.22-3.45]), but not in the fully adjusted model (HR: 0.88 [95% CI: 0.44-1.73]). Particularly, adjustment for glomerular filtration rate and urinary albumin excretion rate attenuated the HR. A similar pattern was observed in unadjusted models for incidence of CVD (HR: 1.58 [95% CI: 1.03-2.42]) and risk of ESKD (HR: 7.62 [95% CI: 4.25-13.68]). In the fully adjusted models, the HRs became statistically insignificant.

CONCLUSION

In persons with type 1 diabetes, lower vitamin K status was associated with higher mortality, CVD and progression to ESKD, however, not after adjustment for other risk factors. Interventional studies are needed to elucidate the role of vitamin K in persons with type 1 diabetes.

Predictive ability of the pedal medial arterial calcification (pMAC) score for major adverse limb events among patients with Chronic Limb-Threatening Ischemia

OBJECTIVE

Pedal medial arterial calcification (pMAC) is a potential predictor of major adverse limb events (MALE) among patients with critical limb-threatening ischemia (CLTI). This study aims to validate the prognostic value of the pMAC score in predicting major lower limb amputation (MLLA) and need for re-do revascularisation.

METHODS

A single centre study involving 196 patients diagnosed with CLTI, reviewed between 2012 and 2022. Patients' pMAC scores were obtained through X-ray assessments. Correlations between pMAC scores and the incidence of MALE and re-do revascularisation, were analysed. A power analysis using G* Power 3 software determined a needed sample size of 157 participants. Statistical analysis employed SPSS 26, utilising descriptive statistics, Chi Square, Mann-Whitney, Kaplan-Meier with log-rank test, and Cox regression for predictor identification.

RESULTS

The cohort was predominantly male (79.1%) and diabetic (59.2%). Re-do revascularisation need was 15.3%, increasing with pMAC scores: 3.3% (low), 24.5% (medium), and 50% (high) (p<0.001). MLLA frequency also rose with pMAC scores: 6.7%, 27.5%, and 50% respectively (p<0.001). Higher pMAC scores correlated with a higher incidence of MALE (p=0.029). Multivariate analysis showed medium pMAC (HR 4.159, p=0.002), high pMAC (HR 7.366, p=0.015), and GLASS stage 3 (HR 3.529, p=0.011) as independent MLLA predictors. Re-do revascularisation predictors included female sex (HR 2.106, p=0.063), Black race (HR 64.498, p=0.001), medium pMAC (HR 6.812, p=0.002), high pMAC (HR 11.455, p=0.008), and GLASS stage 3 (HR 2.899, p=0.037).

CONCLUSION

The pMAC score effectively predicts MALE in CLTI patients and enhances risk stratification. Using both, pMAC scores and GLASS stages enhances predictive accuracy, identifying patients at higher risk for MLLA, Informing clinical decision-making and therapeutic strategies.

Oral pyrophosphate protects Abcc6-/- mice against vascular calcification induced by chronic kidney disease

One of the hallmarks of chronic kidney disease (CKD) is the development of vascular calcification. Inorganic pyrophosphate is a potent inhibitor of calcification, and previous studies have reported low plasma pyrophosphate levels in hemodialysis patients. A long-term mouse model of CKD-accelerated vascular calcification was developed to study pyrophosphate metabolism and to test whether oral pyrophosphate supplementation attenuates the propensity for arterial calcification. CKD was induced by repeated injections of aristolochic acid in wild-type and Abcc6-/- mice, which tend to develop vascular calcifications. CKD accelerated the development of vascular calcifications in Abcc6-/- mice, in the aorta and small renal arteries, and decreased circulating pyrophosphate levels. Oral pyrophosphate supplementation for 6 months attenuated CKD-induced vascular calcification in this model. These results show that oral pyrophosphate may be of interest in preventing vascular calcification in patients with CKD. KEY MESSAGES: Chronic kidney disease accelerates the development of vascular calcification in pyrophosphate-deficient mice. Oral pyrophosphate supplementation for 6 months attenuates chronic kidney disease-induced vascular calcification in a mouse model. Oral pyrophosphate may be of interest in preventing vascular calcification in patients with chronic kidney disease.

Bone Marrow-Derived ABCC6 Is an Essential Regulator of Ectopic Calcification In Pseudoxanthoma Elasticum

Physiological calcification of soft tissues is a common occurrence in aging and various acquired and inherited disorders. ABCC6 sequence variations cause the calcification phenotype of pseudoxanthoma elasticum (PXE) as well as some cases of generalized arterial calcification of infancy, which is otherwise caused by defective ENPP1. ABCC6 is primarily expressed in the liver, which has given the impression that the liver is central to the pathophysiology of PXE/generalized arterial calcification of infancy. The emergence of inflammation as a contributor to the calcification in PXE suggested that peripheral tissues play a larger role than expected. In this study, we investigated whether bone marrow-derived ABCC6 contributes to the calcification in PXE. In Abcc6‒/‒ mice, we observed prevalent mineralization in several lymph nodes and surrounding connective tissues and an extensive network of lymphatic vessels within vibrissae, a calcified tissue in Abcc6‒/‒ mice. Furthermore, we found evidence of lymphangiogenesis in patients with PXE and mouse skin, suggesting an inflammatory process. Finally, restoring wild-type bone marrow in Abcc6‒/‒ mice produced a significant reduction of calcification, suggesting that the liver alone is not sufficient to fully inhibit mineralization. With evidence that ABCC6 is expressed in lymphocytes, we suggest that the adaptative immune system and inflammation largely contribute to the calcification in PXE/generalized arterial calcification of infancy.

Diabetic peripheral arterial disease in COVID-19 pandemic

Both diabetes and peripheral arterial disease (PAD) have complex interactions with COVID-19. PAD is one of the most important underlying factors in the development of diabetic foot. The COVID-19 pandemic has also caused an increase in cardiovascular complications in those with chronic diseases, including diabetics, due to both the thrombophilic course of the viral disease and the lockdown measures applied for prevention. Since both COVID-19 and diabetes mellitus predispose to thrombosis, PAD is likely to have a more severe course in diabetic patients with COVID-19. The aim of our study is to discuss the complications, prophylaxis, and treatment of PAD, which is a serious complication of diabetes, during the pandemic period.

Effect of Doxycycline on Progression of Arterial Calcification in the Noninvasive Treatment of Abdominal Aortic Aneurysm Clinical Trial (N-TA(3)CT)

BACKGROUND

Doxycycline has been shown to prevent arterial calcification via attenuation of matrix metalloproteinases (MMP) in preclinical models. We assessed the effects of doxycycline on progression of arterial calcification in patients enrolled in the Non-Invasive Treatment of Abdominal Aortic Aneurysm Clinical Trial (N-TA3CT).

METHODS

Two hundred and sixty-one patients were randomized to 100 mg doxycycline twice daily or placebo. Arterial calcification was measured in abdominal vessels on noncontrast computed tomography scans. Patients with baseline computed tomography scan and 1 or more follow-up scans within the 2-year study were included for analysis. For individual arteries, mean change in iliofemoral artery calcification over time was calculated via linear regression. Serum MMP-3 and MMP-9 levels were measured at baseline and 6 months.

RESULTS

Sixty-five patients in the doxycycline and 66 in the placebo arm were included in this analysis. Baseline characteristics between the groups were similar. The unadjusted mean change in iliofemoral calcium score per year trended toward higher values in patients treated with doxycycline compared with placebo (322 ± 399 units/year vs. 217 ± 307 units/year, P = 0.09). After 6 months, changes in serum MMP-3 and MMP-9 levels were not significantly different between study arms.

CONCLUSIONS

In patients with small aortic aneurysm, treatment with doxycycline 100 mg twice daily did not decrease circulating levels of the matrix degrading enzymes MMP-3 and 9 or alter the progression of arterial calcification.

High ankle-brachial index participants experienced similar long-term mortality as peripheral artery disease in a national sample of community-dwelling adults

BACKGROUND

Only a few small studies have shown the association between high ankle-brachial pressure index (ABI >1.4) and adverse cardiovascular (CV) events and mortality. Although there is abundant literature depicting the association between ABI and overall systemic atherosclerosis, it typically focuses on low ABI. Furthermore, historically, many studies focusing on peripheral artery disease have excluded high ABI participants. We aimed to study the mortality outcomes of persons with high ABI in the National Health and Nutrition Examination Survey (NHANES).

METHODS

We obtained ABI from participants aged ≥40 years for survey years 1999 to 2004. We defined low a ABI as ≤0.9, normal ABI as 0.9 to 1.4, and high ABI as >1.4 or if the ankle pressures were >245 mm Hg. Demographics, various comorbidities, and laboratory test results were obtained at the time of the survey interview. Multivariable adjusted hazard ratios (HRs) along with 95% confidence intervals (CIs) were calculated for CV and all-cause mortality via Cox proportional hazards regression. Mortality was linked to all NHANES participants for follow-up through December 31, 2019, by the Centers for Disease Control and Prevention.

RESULTS

We identified 7639 NHANES participants with available ABI. Of these, 6787 (89%) had a normal ABI, 646 (8%) had a low ABI, and 206 (3%) had elevated ABI. Of participants with high ABI, 50% were men, 15% were African Americans, 10% were current smokers, 56% had hypertension, 33% had diabetes, 15% had chronic kidney disease (CKD), and 18% had concomitant coronary artery disease (CAD). Diabetes (odds ratio [OR], 2.4; 95% CI, 1.7-3.2), CAD (OR, 1.6; 95% CI, 1.0-2.4), and CKD (OR, 1.5; 95% CI, 1.0-2.3) at baseline were associated with having a high ABI, respectively. A high ABI was associated independently with elevated CV (HR, 2.6; 95% CI, 2.1-3.1; P < .0001) and all-cause mortality (HR, 2.5; 95% CI, 2.2-2.8; P < .0001) after adjusting for covariates, including diabetes, CKD, CAD, current smoking, cancer, and hypertension.

CONCLUSIONS

A high ABI is associated with an elevated CV and all-cause mortality, similar to patients with PAD. High ABI participants should receive the same attention and aggressive medical therapies as patients with PAD.

SNF472: a novel therapeutic agent for vascular calcification and calciphylaxis

Vascular calcification is a common complication in patients with chronic kidney disease (CKD) and is strongly associated with an increased risk of cardiovascular events and all-cause mortality. Calciphylaxis is a specific and life-threatening manifestation of vascular calcifications that usually affects individuals with advanced kidney function impairment or those undergoing dialysis. Currently, the treatment of vascular calcification and calciphylaxis in CKD lacks approved treatments and focuses on controlling risk factors. SNF472, the intravenous formulation of myo-inositol hexaphosphate, is a novel vascular calcification inhibitor currently undergoing phase 3 clinical trials, demonstrating its ability to directly inhibit the formation of calcium and phosphorus crystals, thereby blocking the production and deposition of ectopic calcium. The efficacy and safety of SNF472 in inhibiting vascular calcification have been confirmed in recent clinical studies. This review summarizes the results of studies related to SNF472 to provide a comprehensive overview of its mechanism of action, efficacy, safety, and ongoing clinical studies.

Pedal medial arterial calcification in diabetic foot ulcers: A significant risk factor of amputation and mortality

AIMS

Pedal medial arterial calcification (MAC) is frequently observed in individuals with diabetic foot ulcers (DFUs). However, the impact of pedal MAC on individuals with DFUs remains uncertain. The main aim of this study was to evaluate the association between pedal MAC with amputation and mortality outcomes.

METHODS

A prospective, observational cohort study was conducted at West China Hospital from January 2012 to December 2021. Logistic regression analyses, Kaplan-Meier survival method, and Cox proportional hazards models were employed to evaluate the relationship between pedal MAC and amputation as well as mortality.

RESULTS

A total of 979 patients were enrolled in the study. Peripheral artery disease (PAD) was observed in 53% of patients with DFUs, and pedal MAC was found in 8%. Over a median follow-up of 46 (23-72) months, foot amputation was performed on 190 patients, and mortality occurred in 246 patients. Pedal MAC showed a significant association with amputation both in unadjusted analysis (odds ratio [OR] = 2.98, 95% confidence interval [CI] = 1.86-4.76, p < .001) and after adjusting sex, age, albumin levels, hemoglobin levels, and diabetic retinopathy status (OR 2.29, 95% CI 1.33-3.93, p = .003). The risk of amputation was found to be twofold higher in individuals with PAD and pedal MAC compared to those with PAD alone (OR 2.05, 95% CI 1.10-3.82, p = .024). Furthermore, the presence of pedal MAC was significantly associated with an increased risk of mortality (p = .005), particularly among individuals with DFUs but without PAD (HR 4.26, 95% CI 1.90-9.52, p < .001), rather than in individuals presenting with both DFUs and PAD.

CONCLUSION

The presence of pedal MAC is significantly associated with both amputation and mortality in individuals with DFUs. Moreover, pedal MAC could provide additional value to predict amputation other than PAD.

The intersocietal IWGDF, ESVS, SVS guidelines on peripheral artery disease in people with diabetes and a foot ulcer

Diabetes related foot complications have become a major cause of morbidity and are implicated in most major and minor amputations globally. Approximately 50% of people with diabetes and a foot ulcer have peripheral artery disease (PAD) and the presence of PAD significantly increases the risk of adverse limb and cardiovascular events. The International Working Group on the Diabetic Foot (IWGDF) has published evidence based guidelines on the management and prevention of diabetes related foot complications since 1999. This guideline is an update of the 2019 IWGDF guideline on the diagnosis, prognosis and management of peripheral artery disease in people with diabetes mellitus and a foot ulcer. For this guideline the IWGDF, the European Society for Vascular Surgery and the Society for Vascular Surgery decided to collaborate to develop a consistent suite of recommendations relevant to clinicians in all countries. This guideline is based on three new systematic reviews. Using the Grading of Recommendations, Assessment, Development, and Evaluation framework clinically relevant questions were formulated, and the literature was systematically reviewed. After assessing the certainty of the evidence, recommendations were formulated which were weighed against the balance of benefits and harms, patient values, feasibility, acceptability, equity, resources required, and when available, costs. Through this process five recommendations were developed for diagnosing PAD in a person with diabetes, with and without a foot ulcer or gangrene. Five recommendations were developed for prognosis relating to estimating likelihood of healing and amputation outcomes in a person with diabetes and a foot ulcer or gangrene. Fifteen recommendations were developed related to PAD treatment encompassing prioritisation of people for revascularisation, the choice of a procedure and post-surgical care. In addition, the Writing Committee has highlighted key research questions where current evidence is lacking. The Writing Committee believes that following these recommendations will help healthcare professionals to provide better care and will reduce the burden of diabetes related foot complications.

Effectiveness of bedside investigations to diagnose peripheral artery disease among people with diabetes mellitus: A systematic review

As a progressive disease process, early diagnosis and ongoing monitoring and treatment of lower limb peripheral artery disease (PAD) is critical to reduce the risk of diabetes-related foot ulcer (DFU) development, non-healing of wounds, infection and amputation, in addition to cardiovascular complications. There are a variety of non-invasive tests available to diagnose PAD at the bedside, but there is no consensus as to the most diagnostically accurate of these bedside investigations or their reliability for use as a method of ongoing monitoring. Therefore, the aim of this systematic review was to first determine the diagnostic accuracy of non-invasive bedside tests for identifying PAD compared to an imaging reference test and second to determine the intra- and inter-rater reliability of non-invasive bedside tests in adults with diabetes. A database search of Medline and Embase was conducted from 1980 to 30 November 2022. Prospective and retrospective investigations of the diagnostic accuracy of bedside testing in people with diabetes using an imaging reference standard and reliability studies of bedside testing techniques conducted in people with diabetes were eligible. Included studies of diagnostic accuracy were required to report adequate data to calculate the positive likelihood ratio (PLR) and negative likelihood ratio (NLR) which were the primary endpoints. The quality appraisal was conducted using the Quality Assessment of Diagnostic Accuracy Studies and Quality Appraisal of Reliability quality appraisal tools. From a total of 8517 abstracts retrieved, 40 studies met the inclusion criteria for the diagnostic accuracy component of the review and seven studies met the inclusion criteria for the reliability component of the review. Most studies investigated the diagnostic accuracy of ankle -brachial index (ABI) (N = 38). In people with and without DFU, PLRs ranged from 1.69 to 19.9 and NLRs from 0.29 to 0.84 indicating an ABI <0.9 increases the likelihood of disease (but the extent of the increase ranges from a small to large amount) and an ABI within the normal range (≥0.90 and <1.3) does not exclude PAD. For toe-brachial index (TBI), a threshold of <0.70 has a moderate ability to rule PAD in and out; however, this is based on limited evidence. Similarly, a small number of studies indicate that one or more monophasic Doppler waveforms in the pedal arteries is associated with the presence of PAD, whereas tri- or biphasic waveform suggests that PAD is less likely. Several forms of bedside testing may also be useful as adjunct tests and 7 studies were identified that investigated the reliability of bedside tests including ABI, toe pressure, TBI, transcutaneous oxygen pressure (TcPO2 ) and pulse palpation. Inter-rater reliability was poor for pulse palpation and moderate for TcPO2. The ABI, toe pressure and TBI may have good inter- and intra-rater reliability, but margins of error are wide, requiring a large change in the measurement for it to be considered a true change rather than error. There is currently no single bedside test or a combination of bedside tests that has been shown to have superior diagnostic accuracy for PAD in people with diabetes with or without DFU. However, an ABI <0.9 or >1.3, TBI of <0.70, and absent or monophasic pedal Doppler waveforms are useful to identify the presence of disease. The ability of the tests to exclude disease is variable and although reliability may be acceptable, evidence of error in the measurements means test results that are within normal limits should be considered with caution and in the context of other vascular assessment findings (e.g., pedal pulse palpation and clinical signs) and progress of DFU healing.

Incompressible ankle arteries predict increased morbidity and mortality in patients with an elevated ankle brachial index

OBJECTIVES

Patients with an elevated ankle brachial index (ABI) > 1.3 have a high burden of disease and poorer outcome compared to patients with a lower ABI. Previously differences between patients with ABI > 1.3 have not been studied in detail. The aim of this study was to analyze the morbidity and mortality of patients with ABI > 1.3.

METHODS

ABI measurements were performed in the vascular laboratory of Turku university hospital 2011-2013. Patients with ABI>1.3 in at least one lower limb were included in the study and divided into 3 groups: At least one lower limb ABI 1.3-2.5 but both limbs <2.5 (group 1), one limb ABI ≥2.5 (group 2), both limbs ABI ≥ 2.5 (group 3).

RESULTS

534 patients were included in the study. The patients in groups 2 and 3 were more often female (p < .001), older (p < .001), had more diabetes (p = .013), coronary artery disease (p = .001) and chronic heart (p = .010) and kidney failure (p = .013) compared to patients in group 1. The survival of patients in group 2 and 3 was significantly poorer compared to the patients in group 1 (HR1.6, 95% CI 1.2-2.2, p = .002 and 1.7, 95% CI 1.2-2.3, p < .001, respectively). Overall and cardiovascular mortality was higher in groups 2 and 3 than group 1.39.5% of patients with incompressible ankle arteries (ABI ≥ 2.5) in both lower limbs had toe pressure (TP) <50 mmHg and a poorer survival compared to patients with a higher TP.

CONCLUSIONS

Patients with incompressible ankle arteries have significantly higher overall and cardiovascular mortality and a greater burden of disease compared to the patients with a measurable yet abnormally high ABI. TP is a useful diagnostic tool when ABI is immeasurably high. All patients with ABI > 1.3 should be considered as high cardiovascular risk patients.

The Purinergic Nature of Pseudoxanthoma Elasticum

Pseudoxanthoma Elasticum (PXE) is an inherited disease characterized by elastic fiber calcification in the eyes, the skin and the cardiovascular system. PXE results from mutations in ABCC6 that encodes an ABC transporter primarily expressed in the liver and kidneys. It took nearly 15 years after identifying the gene to better understand the etiology of PXE. ABCC6 function facilitates the efflux of ATP, which is sequentially hydrolyzed by the ectonucleotidases ENPP1 and CD73 into pyrophosphate (PPi) and adenosine, both inhibitors of calcification. PXE, together with General Arterial Calcification of Infancy (GACI caused by ENPP1 mutations) as well as Calcification of Joints and Arteries (CALJA caused by NT5E/CD73 mutations), forms a disease continuum with overlapping phenotypes and shares steps of the same molecular pathway. The explanation of these phenotypes place ABCC6 as an upstream regulator of a purinergic pathway (ABCC6 → ENPP1 → CD73 → TNAP) that notably inhibits mineralization by maintaining a physiological Pi/PPi ratio in connective tissues. Based on a review of the literature and our recent experimental data, we suggest that PXE (and GACI/CALJA) be considered as an authentic "purinergic disease". In this article, we recapitulate the pathobiology of PXE and review molecular and physiological data showing that, beyond PPi deficiency and ectopic calcification, PXE is associated with wide and complex alterations of purinergic systems. Finally, we speculate on the future prospects regarding purinergic signaling and other aspects of this disease.

Association Between Breast Arterial Calcifications and Cardiovascular Disease: A Systematic Review and Meta-analysis

BACKGROUND

Recent studies have shown that breast arterial calcification (BAC) detected on screening mammography is linked to cardiovascular diseases via medial calcification. However, its effect on cardiovascular outcomes remains unclear. Therefore, we conducted a meta-analysis to determine the effect of BAC on cardiovascular outcomes in patients.

METHODS

Three electronic databases (Pubmed, Embase, and Scopus) were searched on May 1, 2022, for studies examining the relationship between BAC and cardiovascular outcomes including cardiac death, acute myocardial infarction, ischemic heart disease, stroke, peripheral artery disease, and heart failure. A random-effects meta-analysis model was used to summarise the studies.

RESULTS

A total of 5 longitudinal studies were included with a combined cohort of 87,865 patients. Significantly, the pooled risk ratio (RR) of the association between BAC and cardiac death was 2.06 (P < 0.00001). BAC was associated with a significantly increased risk of developing other cardiovascular diseases, such as ischemic/hemorrhagic stroke (RR 1.51; P = 0.003), ischemic stroke (RR 1.82; P < 0.00001), peripheral vascular disease (RR 1.24; P = 0.003), and heart failure (RR 1.84; P < 0.00001). There was no significant relationship for developing myocardial infarction or for total cardiovascular diseases.

CONCLUSIONS

Our findings suggest that BAC was associated with an increased risk of cardiovascular mortality, and certain cardiovascular outcomes. There is thus a potential to use BAC as a sex-specific cardiovascular risk assessment tool. Furthermore, there is a need for more widespread reporting of BAC to better understand the pathophysiologic mechanisms behind its correlation with cardiovascular disease and to apply it in clinical practice.

Lower limb arterial calcification and its clinical relevance with peripheral arterial disease

Lower limb arterial calcification (LLAC) is associated with an increased risk of mortality and it predicts poor outcomes after endovascular interventions in patients with peripheral artery disease (PAD). Detailed histological analysis of human lower artery specimens pinpointed the presence of LLAC in two distinct layers: the intima and the media. Intimal calcification has been assumed to be an atherosclerotic pathology and it is associated with smoking and obesity. It becomes instrumental in lumen stenosis, thereby playing a crucial role in disease progression. On the contrary, medial calcification is a separate process, systematically regulated and linked with age advancement, diabetes, and chronic kidney disease. It prominently interacts with vasodilation and arterial stiffness. Given that both types of calcifications frequently co-exist in PAD patients, it is vital to understand their respective mechanisms within the context of PAD. Calcification can be easily identifiable entity on imaging scans. Considering the highly improved abilities of novel imaging technologies in differentiating intimal and medial calcification within the lower limb arteries, this review aimed to describe the distinct histological and imaging features of the two types of LLAC. Additionally, it aims to provide in-depth insight into the risk factors, the effects on hemodynamics, and the clinical implications of LLAC, either occurring in the intimal or medial layers.

Leucine-Rich Alpha-2 Glycoprotein 1 Accumulates in Complicated Atherosclerosis and Promotes Calcification

Atherosclerosis is the primary cause of cardiovascular disease. The development of plaque complications, such as calcification and neo-angiogenesis, strongly impacts plaque stability and is a good predictor of mortality in patients with atherosclerosis. Despite well-known risk factors of plaque complications, such as diabetes mellitus and chronic kidney disease, the mechanisms involved are not fully understood. We and others have identified that the concentration of circulating leucine-rich α-2 glycoprotein 1 (LRG1) was increased in diabetic and chronic kidney disease patients. Using apolipoprotein E knockout mice (ApoE-/-) (fed with Western diet) that developed advanced atherosclerosis and using human carotid endarterectomy, we showed that LRG1 accumulated into an atherosclerotic plaque, preferentially in calcified areas. We then investigated the possible origin of LRG1 and its functions on vascular cells and found that LRG1 expression was specifically enhanced in endothelial cells via inflammatory mediators and not in vascular smooth muscle cells (VSMC). Moreover, we identified that LRG1 was able to induce calcification and SMAD1/5-signaling pathways in VSMC. In conclusion, our results identified for the first time that LRG1 is a direct contributor to vascular calcification and suggest a role of this molecule in the development of plaque complications in patients with atherosclerosis.

Dichotomous grouping of peripheral arterial calcification grades: A practical predictor of outcome after endovascular therapy in peripheral arterial disease

BACKGROUND

There is a general agreement that arterial calcification affects the results of endovascular therapy for peripheral arterial disease (PAD). In addition to lacking evidence for their impact, existing calcification scores are complex, and not practical in everyday decision making. The global limb anatomic staging system (GLASS) adopted dichotomous grouping of calcification grades.

OBJECTIVE

In this study we aim to investigate the impact of peripheral arterial calcification scoring after dichotomous grouping on midterm outcomes following endovascular therapy for PAD.

METHODS

This prospective study included all consecutive patients with PAD indicated for endovascular therapy procedure who presented to our tertiary referral center in the period between October 2020 and October 2021. Patients were grouped into Group A (n = 40): with no-to mild calcification (PACSS grade 0,1 and 2), and Group B (n = 53): with severe calcification (PACSS grades 3 and 4). Primary endpoints included technical success rate, primary patency rates, and major adverse limb events rate (MALE) during 2 years of follow-up.

RESULTS

The mean age of the studied cases (n = 93) was 59.31 ± 6.46 years (range 50-75). 70 patients (75.3%) were males, and 23 (24.7%) were females. There was no statistically significant difference between the two groups regarding technical success rate (97.5% in group A versus 94.33% in Group B, p = .457). The Primary patency rate after 1 year was lower in group B (74%) compared to group A (89.7%), but this difference was not statistically significant (p = .059). However, the 2-year primary patency rate was significantly lower in group B compared to group A (64% versus 84.6% respectively, p = .034). MALE rate after 2 years was significantly higher in group B (28%) as compared to group A (10.4%), P = .048. Studying suspected risk factors revealed that severe calcification was more common in patients with ischemic heart disease (34%) and chronic kidney disease (11%), P= .003 and .002 respectively. Logistic regression analysis showed that patients suffered from IHD and those with length of lesion ≥ 5 cm are about five times more likely to have severe calcification compared to their counterparts (OR = 4.875, 95%CI = 1.293-18.383, p = .019, and OR = 4.513, 95% CI = 11.138-17.893, p = .032), respectively.

CONCLUSION

The presence of severe calcification is associated with significantly lower midterm primary patency rates and higher rate of major adverse limb events after endovascular intervention for lower limb denovo arterial lesions.

The intersocietal IWGDF, ESVS, SVS guidelines on peripheral artery disease in people with diabetes mellitus and a foot ulcer

Diabetes related foot complications have become a major cause of morbidity and are implicated in most major and minor amputations globally. Approximately 50% of people with diabetes and a foot ulcer have peripheral artery disease (PAD) and the presence of PAD significantly increases the risk of adverse limb and cardiovascular events. The International Working Group on the Diabetic Foot (IWGDF) has published evidence based guidelines on the management and prevention of diabetes related foot complications since 1999. This guideline is an update of the 2019 IWGDF guideline on the diagnosis, prognosis, and management of peripheral artery disease in people with diabetes mellitus and a foot ulcer. For this updated guideline, the IWGDF, the European Society for Vascular Surgery, and the Society for Vascular Surgery decided to collaborate to develop a consistent suite of recommendations relevant to clinicians in all countries. This guideline is based on three new systematic reviews. Using the Grading of Recommendations, Assessment, Development and Evaluation framework clinically relevant questions were formulated, and the literature was systematically reviewed. After assessing the certainty of the evidence, recommendations were formulated which were weighed against the balance of benefits and harms, patient values, feasibility, acceptability, equity, resources required, and when available, costs. Through this process five recommendations were developed for diagnosing PAD in a person with diabetes, with and without a foot ulcer or gangrene. Five recommendations were developed for prognosis relating to estimating likelihood of healing and amputation outcomes in a person with diabetes and a foot ulcer or gangrene. Fifteen recommendations were developed related to PAD treatment encompassing prioritisation of people for revascularisation, the choice of a procedure and post-surgical care. In addition, the Writing Committee has highlighted key research questions where current evidence is lacking. The Writing Committee believes that following these recommendations will help healthcare professionals to provide better care and will reduce the burden of diabetes related foot complications.

Automated Measurement of Vascular Calcification in Femoral Endarterectomy Patients Using Deep Learning

Atherosclerosis, a chronic inflammatory disease affecting the large arteries, presents a global health risk. Accurate analysis of diagnostic images, like computed tomographic angiograms (CTAs), is essential for staging and monitoring the progression of atherosclerosis-related conditions, including peripheral arterial disease (PAD). However, manual analysis of CTA images is time-consuming and tedious. To address this limitation, we employed a deep learning model to segment the vascular system in CTA images of PAD patients undergoing femoral endarterectomy surgery and to measure vascular calcification from the left renal artery to the patella. Utilizing proprietary CTA images of 27 patients undergoing femoral endarterectomy surgery provided by Prisma Health Midlands, we developed a Deep Neural Network (DNN) model to first segment the arterial system, starting from the descending aorta to the patella, and second, to provide a metric of arterial calcification. Our designed DNN achieved 83.4% average Dice accuracy in segmenting arteries from aorta to patella, advancing the state-of-the-art by 0.8%. Furthermore, our work is the first to present a robust statistical analysis of automated calcification measurement in the lower extremities using deep learning, attaining a Mean Absolute Percentage Error (MAPE) of 9.5% and a correlation coefficient of 0.978 between automated and manual calcification scores. These findings underscore the potential of deep learning techniques as a rapid and accurate tool for medical professionals to assess calcification in the abdominal aorta and its branches above the patella.

Microarray Expression Profile and Bioinformatic Analysis of Circular RNA in Human Arteriosclerosis Obliterans

Background

Arteriosclerosis obliterans (ASO) is the leading cause of nontraumatic lower-extremity amputations. Multiple researches have suggested that circular RNAs (circRNAs) played vital regulatory functions in cancer and cardiovascular disease. Nevertheless, the underlying effect and pathological mechanism of circRNAs in the formation and progression of ASO are still indistinct.

Methods and Results

This study used microarray analysis to investigate the expression portrait of circRNAs in normal lower extremity arteries and ASO arteries. Bioinformatics analysis was conducted using the KEGG database to study the enrichment of differentially expressed circRNAs (DE circRNAs) and predict their functions. The accuracy of microarray assay was verified by evaluating expression of the top 5 upregulated and 5 downregulated circRNAs (raw density of normal group ≥200) using RT-qPCR. A circRNA-miRNA-mRNA interaction network was further predicted using software. Compared to the normal lower extremity group, the ASO arteries with HE and EVG staining presented hyperplastic fibrous membrane and luminal stenosis. A total of 12,735 circRNAs were identified, including 1196 DE circRNAs with 276 upregulated and 920 downregulated in ASO group based on |log2(FC)| > 1 and padj < 0.05. Among selected 10 circRNAs, RT-qPCR confirmed that hsa_circ_0003266, hsa_circ_0118936 and hsa_circ_0067161 were upregulated while hsa_circ_0091934 and hsa_circ_0092022 were downregulated in ASO group (p < 0.05). GO analysis presented that the DE circRNAs were primarily enriched in protein binding, intracellular part and organelle organization. KEGG pathway analysis indicated that MAPK signaling pathway, human T-cell leukemia virus 1 infection, proteoglycans in cancer were associated with the DE circRNAs. The circRNA-miRNA-mRNA interactive network revealed that both mRNAs and miRNAs linked to circRNAs played an indispensable role in ASO.

Conclusion

This study described the expression portrait of circRNAs in human ASO arteries, and revealed the molecular background for further investigations of the circRNA regulatory mechanism in the formation and progression of ASO.

The Intersocietal IWGDF, ESVS, SVS Guidelines on Peripheral Artery Disease in People With Diabetes Mellitus and a Foot Ulcer

Diabetes related foot complications have become a major cause of morbidity and are implicated in most major and minor amputations globally. Approximately 50% of people with diabetes and a foot ulcer have peripheral artery disease (PAD) and the presence of PAD significantly increases the risk of adverse limb and cardiovascular events. The International Working Group on the Diabetic Foot (IWGDF) has published evidence based guidelines on the management and prevention of diabetes related foot complications since 1999. This guideline is an update of the 2019 IWGDF guideline on the diagnosis, prognosis, and management of peripheral artery disease in people with diabetes mellitus and a foot ulcer. For this updated guideline, the IWGDF, the European Society for Vascular Surgery, and the Society for Vascular Surgery decided to collaborate to develop a consistent suite of recommendations relevant to clinicians in all countries. This guideline is based on three new systematic reviews. Using the Grading of Recommendations, Assessment, Development and Evaluation framework clinically relevant questions were formulated, and the literature was systematically reviewed. After assessing the certainty of the evidence, recommendations were formulated which were weighed against the balance of benefits and harms, patient values, feasibility, acceptability, equity, resources required, and when available, costs. Through this process five recommendations were developed for diagnosing PAD in a person with diabetes, with and without a foot ulcer or gangrene. Five recommendations were developed for prognosis relating to estimating likelihood of healing and amputation outcomes in a person with diabetes and a foot ulcer or gangrene. Fifteen recommendations were developed related to PAD treatment encompassing prioritisation of people for revascularisation, the choice of a procedure and post-surgical care. In addition, the Writing Committee has highlighted key research questions where current evidence is lacking. The Writing Committee believes that following these recommendations will help healthcare professionals to provide better care and will reduce the burden of diabetes related foot complications.

Evaluation of Lower Extremity Calcium Score as a Measure of Peripheral Arterial Disease Burden and Amputation Risk

BACKGROUND

The ankle-brachial pressure index (ABI) and toe-brachial pressure index (TBI) are commonly used diagnostic tools for peripheral artery disease (PAD) that are unreliable in the presence of calcified vessels. In this study, we aimed to demonstrate the utility of the lower extremity calcium score (LECS) in addition to ABI and TBI in measuring disease burden and predicting the risk of amputation in patients with PAD.

METHODS

Patients who were evaluated in the vascular surgery clinic at Emory University for PAD and who underwent noncontrast computed tomography of the aorta and lower extremities were included in the study. Aortoiliac, femoral-popliteal, and tibial calcium scores were measured using the Agatston method. ABI and TBI that were obtained within 6 months of the computed tomography scan were noted and divided into categories of PAD severity. Associations between ABI, TBI, and LECS of each anatomic segment were evaluated. Univariate and multivariate ordinal regression analyses were performed to predict the outcome of amputation. Receiver operating characteristic analysis was performed to compare LECS with other variables in its ability to predict amputation.

RESULTS

Fifty patients included in the study cohort were divided into LECS quartiles, with 12-13 patients in each quartile. The highest quartile tended to be older (P = 0.016), had a higher percentage of diabetics (P = 0.034), and had a higher frequency of major amputations (P = 0.004) compared to the other quartiles. Patients in the highest quartile of tibial calcium score were more likely to have stage 3 chronic kidney disease (CKD) or greater (P = 0.011) and also had a higher frequency of amputation (P < 0.005) and mortality (P = 0.041). We found no significant association between each anatomic LECS and ABI/TBI categories. On univariate analysis, CKD (Odds Ratio [OR] 12.92 (95% CI 2.01 to 82.83), P = 0.007), diabetes mellitus (OR 5.47 (95% CI 1.27 to 23.64), P = 0.023), tibial calcium score (OR 6.62 (95% CI 1.79 to 24.54), P = 0.005), and total bilateral calcium score (OR 6.32 (95% CI 1.18 to 33.78), P = 0.031) were associated with increased risk of amputation. On multivariate stepwise ordinal regression, TBI and tibial calcium score were identified as important predictors of amputation, with hyperlipidemia and CKD increasing the overall prediction of the model. On Receiver operating characteristic analysis, the addition of the tibial calcium score (area under the curve 0.94, standard error 0.048) significantly improved the prediction of amputation compared to hyperlipidemia, CKD, and TBI alone (area under the curve 0.82, standard error 0.071, P = 0.022).

CONCLUSIONS

The addition of tibial calcium score to other known PAD risk factors may improve the prediction of amputation in patients with PAD.

Acute Coronary Syndrome: Disparities of Pathophysiology and Mortality with and without Peripheral Artery Disease

There are a number of devastating complications associated with peripheral artery disease, including limb amputations and acute limb ischemia. Despite the overlap, atherosclerotic diseases have distinct causes that need to be differentiated and managed appropriately. In coronary atherosclerosis, thrombosis is often precipitated by rupture or erosion of fibrous caps around atheromatous plaques, which leads to acute coronary syndrome. Regardless of the extent of atherosclerosis, peripheral artery disease manifests itself as thrombosis. Two-thirds of patients with acute limb ischemia have thrombi associated with insignificant atherosclerosis. A local thrombogenic or remotely embolic basis of critical limb ischemia may be explained by obliterative thrombi in peripheral arteries of patients without coronary artery-like lesions. Studies showed that thrombosis of the above-knee arteries was more commonly due to calcified nodules, which are the least common cause of luminal thrombosis associated with acute coronary events in patients with acute coronary syndrome. Cardiovascular mortality was higher in peripheral artery disease without myocardial infarction/stroke than in myocardial infarction/stroke without peripheral artery disease. The aim of this paper is to gather published data regarding the disparities of acute coronary syndrome with and without peripheral artery disease in terms of pathophysiology and mortality.

Mönckeberg's Disease With Calcified Lower Limb Ischemia in Saudi Arabia: A Rare Case Report and Literature Review

Mönckeberg's disease, a rare medial calcific arteriosclerosis, predominantly affects lower extremity arteries with an unclear etiology. If untreated, severe complications like ischemic necrosis and gangrene may arise. We present a case of a 28-year-old male with spontaneous lower limb swelling, abscess, and itching. Despite a history of deep vein thrombosis and warfarin therapy, Mönckeberg's disease was suspected. Imaging revealed diffuse vascular calcification of the media of the arterial wall bilaterally in the right and left femoral vessels with heterogenous irregular soft tissue collection in the right with suspected infection. Following treatment, the patient's symptoms improved, and follow-up imaging showed resolution of fluid collections and improved calcification appearance. This report highlights the importance of considering Mönckeberg's disease in the differential diagnosis of lower extremity swelling and the need for timely management to prevent serious complications.

Epidermal growth factor receptor inhibition prevents vascular calcifying extracellular vesicle biogenesis

Chronic kidney disease (CKD) increases the risk of cardiovascular disease, including vascular calcification, leading to higher mortality. The release of calcifying extracellular vesicles (EVs) by vascular smooth muscle cells (VSMCs) promotes ectopic mineralization of vessel walls. Caveolin-1 (CAV1), a structural protein in the plasma membrane, plays a major role in calcifying EV biogenesis in VSMCs. Epidermal growth factor receptor (EGFR) colocalizes with and influences the intracellular trafficking of CAV1. Using a diet-induced mouse model of CKD followed by a high-phosphate diet to promote vascular calcification, we assessed the potential of EGFR inhibition to prevent vascular calcification. Furthermore, we computationally analyzed 7,651 individuals in the Multi-Ethnic Study of Atherosclerosis (MESA) and Framingham cohorts to assess potential correlations between coronary artery calcium and single-nucleotide polymorphisms (SNPs) associated with elevated serum levels of EGFR. Mice with CKD developed widespread vascular calcification, associated with increased serum levels of EGFR. In both the CKD mice and human VSMC culture, EGFR inhibition significantly reduced vascular calcification by mitigating the release of CAV1-positive calcifying EVs. EGFR inhibition also increased bone mineral density in CKD mice. Individuals in the MESA and Framingham cohorts with SNPs associated with increased serum EGFR exhibit elevated coronary artery calcium. Given that EGFR inhibitors exhibit clinical safety and efficacy in other pathologies, the current data suggest that EGFR may represent an ideal target to prevent pathological vascular calcification in CKD.NEW & NOTEWORTHY Here, we investigate the potential of epidermal growth factor receptor (EGFR) inhibition to prevent vascular calcification, a leading indicator of and contributor to cardiovascular morbidity and mortality. EGFR interacts and affects the trafficking of the plasma membrane scaffolding protein caveolin-1. Previous studies reported a key role for caveolin-1 in the development of specialized extracellular vesicles that mediate vascular calcification; however, no role of EGFR has been reported. We demonstrated that EGFR inhibition modulates caveolin-1 trafficking and hinders calcifying extracellular vesicle formation, which prevents vascular calcification. Given that EGFR inhibitors are clinically approved for other indications, this may represent a novel therapeutic strategy for vascular calcification.

Prosthetic vascular grafts engineered to combat calcification: Progress and future directions

Calcification in prosthetic vascular conduits is a major challenge in cardiac and vascular surgery that compromises the long-term performance of these devices. Significant research efforts have been made to understand the etiology of calcification in the cardiovascular system and to combat calcification in various cardiovascular devices. Novel biomaterial design and tissue engineering strategies have shown promise in preventing or delaying calcification in prosthetic vascular grafts. In this review, we highlight recent advancements in the development of acellular prosthetic vascular grafts with preclinical success in attenuating calcification through advanced biomaterial design. We also discuss the mechanisms of action involved in the designs that will contribute to the further understanding of cardiovascular calcification. Lastly, recent insights into the etiology of vascular calcification will guide the design of future prosthetic vascular grafts with greater potential for translational success.

Medial artery calcification in peripheral artery disease

Medial artery calcification (MAC) is a distinct, highly regulated process that is often identified in small and mid-sized arteries of the lower extremities. It is associated with advanced age, diabetes, and chronic kidney disease. MAC often occurs in conjunction with atherosclerotic occlusive disease in lower extremity arteries, and when seen together or in isolation, long-term limb outcomes are negatively affected. In patients with peripheral artery disease (PAD), the extent of MAC independently correlates with major amputation and mortality rates, and it predicts poor outcomes after endovascular interventions. It is associated with increased arterial stiffness and decreased pedal perfusion. New endovascular methods aimed at treating calcified lower-extremity lesions may improve our ability to treat patients with limb-threatening ischemia. Although recent developments have increased our understanding of the mechanisms contributing to MAC, further investigations are needed to understand the role of medial calcification in PAD, and to develop strategies aimed at improving patient outcomes.

Weakness of lower limb muscle in symptomatic peripheral artery disease with media sclerosis detected by ultrasound shear wave elastography

Background: Symptomatic peripheral arterial disease (PAD) is difficult to non-invasively diagnose in the presence of calcified, media sclerotic arteries that are incompressible by blood pressure cuffs. Standard ankle-brachial index (ABI) measurements in these PAD patients are very often not helpful. Shear wave elastography (SWE) is a modern ultrasound technique to detect peripheral muscle stiffness changes i.e. muscle weakness during exercise. In a pilot study, we examined whether SWE could be a reproducible tool for diagnosing ischemic loss of muscle stiffness in patients with PAD and concomitant arterial media sclerosis. Patients and methods: N=13 consecutive patients with peripheral artery disease and media sclerosis were enrolled in the pilot study. All 13 patients were symptomatic in different stages of their PAD due to hemodynamically relevant arterial stenosis or occlusions of limb arteries as confirmed by oscillography, color-coded duplex sonography or angiography. Results: ABI measurements were invalid in all 13 patients. Mean SWE measurements of medial gastrocnemius muscles showed a significant transient muscle stiffness loss (weakness) at maximum exercise (active dorsal flexion of the foot, 103.4±25.9 kPa on the asymptomatic vs. 62.5±21.9 kPa on the symptomatic limb (p<0.001). Conclusions: SWE can reproducibly detect peripheral muscle weakness during exercise in the symptomatic leg of media sclerotic PAD patients. SWE of lower limb muscles may help to identify symptomatic PAD in patients presenting with invalid ABI measurements and unclear vascular status.

Targeting a Silent Disease: Vascular Calcification in Chronic Kidney Disease

Chronic kidney disease (CKD) patients have a higher risk of developing early cardiovascular disease (CVD). Although vascular calcification (VC) is one of the strongest predictors of CVD risk, its diagnosis among the CKD population remains a serious clinical challenge. This is mainly due to the complexity of VC, which results from various interconnected pathological mechanisms occurring at early stages and at multiples sites, affecting the medial and intimal layers of the vascular tree. Here, we review the most used and recently developed imaging techniques, here referred to as imaging biomarkers, for VC detection and monitoring, while discussing their strengths and limitations considering the specificities of VC in a CKD context. Although imaging biomarkers have a crucial role in the diagnosis of VC, with important insights into CVD risk, circulating biomarkers represent an added value by reflecting the molecular dynamics and mechanisms involved in VC pathophysiological pathways, opening new avenues into the early detection and targeted interventions. We propose that a combined strategy using imaging and circulating biomarkers with a role in multiple VC molecular mechanisms, such as Fetuin-A, Matrix Gla protein, Gla-rich protein and calciprotein particles, should represent high prognostic value for management of CVD risk in the CKD population.

Endothelial cell dysfunction: Implications for the pathogenesis of peripheral artery disease

Peripheral artery disease (PAD) is caused by occluded or narrowed arteries that reduce blood flow to the lower limbs. The treatment focuses on lifestyle changes, management of modifiable risk factors and vascular surgery. In this review we focus on how Endothelial Cell (EC) dysfunction contributes to PAD pathophysiology and describe the largely untapped potential of correcting endothelial dysfunction. Moreover, we describe current treatments and clinical trials which improve EC dysfunction and offer insights into where future research efforts could be made. Endothelial dysfunction could represent a target for PAD therapy.

Molecular mechanisms and effects of urocortin II on rat adventitial fibroblast calcification induced by calcified medium

The present study aimed to assess the role of urocortin II (UII) in the process of vascular calcification in vitro by using a calcification model, to detect the changes in the mRNA and protein levels of associated markers in rat adventitial fibroblasts (AFs) during their phenotypic transformation to osteoblast cellsto clarify the main signal transduction pathway of UII responsible for regulating vascular calcification and AF phenotypic transformation of osteoblast cells, and to prove that UII was an endogenous factor promoting vascular calcification, so as to provide an effective experimental basis for the clinical regulation of related diseases caused by vascular calcification. Finally, we successfully constructed the calcified cell model, found that UII was an endogenous substance regulating vascular calcification, regulated the vascular calcification by promoting apoptosis and inhibiting autophagy through up- and downregulated BAX and BCL-2/BECLIN 1 (BECN1) level, and the Wnt/β-catenin signaling pathway was involved.

Shockwave lithotripsy for treatment of calcific renal artery stenosis after an inadequately expanded renal artery stent

Renal artery calcifications can be associated with insufficient stent expansion and in-stent restenosis. Intravascular lithotripsy (IVL) uses shockwaves to disrupt calcium and treat calcific renal in-stent restenosis. Herein, the authors present a case to treat resistant reno-vascular hypertension and in-stent restenosis of an inadequately expanded renal stent in a patient with severe calcific renal artery stenosis. The patient was treated with IVL and stent dilation. The patient was followed subsequently, and her home blood pressure was well controlled on anti-hypertensive medications. In conclusion, IVL promises pronounced success in the modification of severely calcified renal artery lesions and can be used to treat renal artery stenosis even in the context of inadequately expanding renal artery stents.

Senescence in Vascular Smooth Muscle Cells and Atherosclerosis

Vascular smooth muscle cells (VSMCs) are the primary cell type involved in the atherosclerosis process; senescent VSMCs are observed in both aged vessels and atherosclerotic plaques. Factors associated with the atherosclerotic process, including oxidative stress, inflammation, and calcium-regulating factors, are closely linked to senescence in VSMCs. A number of experimental studies using traditional cellular aging markers have suggested that anti-aging biochemical agents could be used to treat atherosclerosis. However, doubt has recently been cast on such potential due to the increasingly apparent complexity of VSMCs status and an incomplete understanding of the role that these cells play in the atherosclerosis process, as well as a lack of specific or spectrum-limited cellular aging markers. The utility of anti-aging drugs in atherosclerosis treatment should be reevaluated. Promotion of a healthy lifestyle, exploring in depth the characteristics of each cell type associated with atherosclerosis, including VSMCs, and development of targeted drug delivery systems will ensure efficacy whilst evaluation of the safety and tolerability of drug use should be key aims of future anti-atherosclerosis research. This review summarizes the characteristics of VSMC senescence during the atherosclerosis process, the factors regulating this process, as well as an overview of progress toward the development and application of anti-aging drugs.

Vascular Calcification in Chronic Kidney Disease: An Update and Perspective

Chronic kidney disease is a devastating condition resulting from irreversible loss of nephron numbers and function and leading to end-stage renal disease and mineral disorders. Vascular calcification, an ectopic deposition of calcium-phosphate salts in blood vessel walls and heart valves, is an independent risk factor of cardiovascular morbidity and mortality in chronic kidney disease. Moreover, aging and related metabolic disorders are essential risk factors for chronic kidney disease and vascular calcification. Marked progress has been recently made in understanding and treating vascular calcification in chronic kidney disease. However, there is a paucity of systematic reviews summarizing this progress, and investigating unresolved issues is warranted. In this systematic review, we aimed to overview the underlying mechanisms of vascular calcification in chronic kidney diseases and discuss the impact of chronic kidney disease on the pathophysiology of vascular calcification. Additionally, we summarized potential clinical diagnostic biomarkers and therapeutic applications for vascular calcification with chronic kidney disease. This review may offer new insights into the pathogenesis, diagnosis, and therapeutic intervention of vascular calcification.

Stem Cell-derived Exosomal MicroRNA as Therapy for Vascular Age-related Diseases

Vascular age-related diseases describe a group of age-related chronic diseases that result in a considerable healthcare burden to society. Vascular aging includes structural changes and dysfunctions of endothelial cells (ECs) and smooth muscle cells (SMCs) in blood vessels. Compared with conventional treatment for vascular age-related diseases, stem cell (SC) therapy elicits better anti-aging effects viathe inhibition/delay ECs and SMCs from entering senescence. Exosomal noncoding RNA (ncRNAs) in vascular aging and stem cell-derived exosomal microRNAs (SCEV-miRNAs), especially in mesenchymal stem cells, have an important role in the development of age-related diseases. This review summarizes SCEV-miRNAs of diverse origins that may play a vital role in treating subclinical and clinical stages of vascular age-related disorders. We further explored possible age-related pathways and molecular targets of SCEV-miRNA, which are associated with dysfunctions of ECs and SMCs in the senescent stage. Moreover, the perspectives and difficulties of SCEV-miRNA clinical translation are discussed. This review aims to provide greater understanding of the biology of vascular aging and to identify critical therapeutic targets for SCEV-miRNAs. Though still in its infancy, the potential value of SCEV-miRNAs for vascular age-related diseases is clear.

Potential Actions of Baicalein for Preventing Vascular Calcification of Smooth Muscle Cells In Vitro and In Vivo

Vascular calcification (VC) is associated with cardiovascular disease. Baicalein, a natural flavonoid extract of Scutellaria baicalensis rhizome has several biological properties which may inhibit VC. We investigated whether baicalein suppresses Runt-related transcription factor 2 (Runx2) and bone morphogenetic protein 2 (BMP-2) and upregulates smooth muscle 22-alpha (SM22-α) and alpha-smooth muscle actin (α-SMA). In an in vitro experiment, primary rat aortic vascular smooth muscle cells (VSMCs) were pretreated with 0.1, 1, and 5 μM baicalein, followed by β-glycerophosphate (β-GP) to induce calcification. In an in vivo experiment, VC was generated by vitamin D3 plus nicotine (VDN) administration to male Sprague Dawley (SD) rats randomly assigned into a control group, a VC group, a VC group pretreated with baicalein, and a baicalein alone group. Each group comprised 10 rats. Left ventricular (LV) morphology, function and performance were assessed by echocardiography. Calcium content was measured by Alizarin red S staining and alkaline phosphatase (ALP) activity assays. Apoptotic VSMCs were detected by flow cytometry. Protein levels and superoxide changes were evaluated using Western blotting and immunofluorescence assays respectively. Plasma malondialdehyde (MDA) was assayed. Baicalein pretreatment significantly reduced calcium content in calcified VSMCs (p < 0.001) as well as in VC rat aortic smooth muscle (p < 0.001). Additionally, ALP activity was decreased in calcified VSMCs and VC rat aortic smooth muscle (p < 0.001). Apoptosis was significantly attenuated by 1 μM baicalein pretreatment in calcified VSMCs. Runx2 and BMP-2 expressions were downregulated by the baicalein in calcified VSMCs. Baicalein pretreatment increased typical VSMCs markers SM22-α and α-SMA in calcified VSMCs. Baicalein pretreatment was associated with adverse changes in LV morphometry. Markers of oxidative stress declined, and endogenous antioxidants increased in VC rats pretreated with baicalein. Baicalein mitigates VC through the inhibition of Runx2/BMP-2 signaling pathways, enhancement of vascular contractile phenotype and oxidative stress reduction. However, our study is of basic experimental design; more advanced investigations to identify other molecular regulators of VC and their mechanisms of action is required.

Radiography and Computed Tomography Detection of Intimal and Medial Calcifications in Leg Arteries in Comparison to Histology

Calcifications are common in the tunica intima and tunica media of leg arteries. There is growing interest in medial arterial calcifications, as they may be modifiable with treatment. We aimed to investigate radiography and computed tomography (CT) for the detection and characterization of both types of arterial calcification in leg arteries in relation to histology. In a postmortem study we therefore investigated 24 popliteal and 24 tibial arteries. The reference standard was presence of arterial calcification and the dominance of intimal or medial calcification on histology. Radiographs and CT scans were scored for presence of calcification and for dominant intimal or medial pattern based on prespecified criteria (annularity, thickness, continuity). Both radiography and CT detected 87% of histologically proven calcifications but missed mild calcifications in 13%. When only the arteries with detected calcifications were included, a moderate agreement was observed on intimal/medial location of calcifications between histology and radiography (correct in 19/24 arteries (79%); Kappa 0.58) or CT (correct in 33/46 arterial segments (72%); Kappa 0.48). With both modalities there was a slight tendency to classify intimal calcifications as being located in the media and to miss media calcification. Our study demonstrates the potential and limitations of both radiography and CT to detect and classify arterial calcifications in leg arteries.

Ultrasonography evaluation on the protective effect of combination therapy of beraprost sodium and aspirin on arteries occlusion and stiffness in patients with type 2 diabetes mellitus - a prospective, randomized study

BACKGROUND

Patients with type 2 diabetes mellitus (T2DM) are susceptible to developing symptomatic peripheral arterial disease (PAD). As a proven vasodilator and antiplatelet agent, the efficiency of Beraprost sodium (BPS) on the prevention of arteries occlusion and stiffness in T2DM patients with PAD has not yet been fully investigated.

METHODS

From July 2010 to April 2012, 64 Patients enrolled were randomly assigned to the combined therapy group (n=32), which received combination therapy with BPS (60 μg/day) and aspirin (100 mg/day), or to the control group (n=32), which only received aspirin (100 mg/day). After randomization, the patients were followed up at years 0, 1, 2, 3, 4, and 5 with the evaluation of carotid intima-media thickness (CIMT), pulse wave velocity (PWV), inner artery diameter, stenosis rate, and medial arterial calcification (MAC) of lower limb arteries via high-resolution ultrasound measurement. Adverse events were also recorded in each visit.

RESULTS

There was no significant change of the CIMT during the follow-up in both groups when compared to the baseline. Similar results were also observed in the PWV measurement. Significantly increases in the inner artery diameter of the dorsal pedal artery and posterior tibial artery were observed in patients with BPS and aspirin administration during the follow-up. Patients in the combined therapy group experienced marked improvement of MAC in the dorsal pedal artery and posterior tibial artery at the end of the follow-up. No significant difference in the adverse events was found between the combined therapy group and the aspirin group.

CONCLUSION

The combined therapy of BPS and aspirin showed a protective effect on arteries occlusion and stiffness in T2DM patients with PAD, along with a significant improvement of inner artery diameter and MAC in lower limbs.

TRIAL REGISTRATION

http://www.chictr.org.cn , ChiCTR-TRC-10000919. Prospectively registered on 2010/06/29.

Occult Mönckeberg medial calcinosis of the facial and infraorbital arteries in an elderly edentulous patient

Mönckeberg medial calcinosis (MMC) is a potentially serious vasculopathy involving calcification of the arterial tunica media of the extremities, heart, and other viscera. There are a limited number of cases reported in the dental literature, usually associated with the facial artery. Although MMC is often discerned as an occult radiologic finding in middle-aged adults, its presence may serve as a harbinger for end-stage renal disease, diabetes, other pathologic processes, and possible regional hypoperfusion. The objective of this report is to feature an elderly patient with MMC of the facial and infraorbital arteries. In addition, a brief review of published cases of MMC and its differential diagnosis have been provided. It is recommended that affected patients be referred for a comprehensive medical assessment. Timely discovery of calcified arteries may improve patient outcomes.

Pro-Calcific Environment Impairs Ischaemia-Driven Angiogenesis

Peripheral arterial disease (PAD) is characterised by accelerated arterial calcification and impairment in angiogenesis. Studies implicate vascular calcification as a contributor to PAD, but the mechanisms remain unclear. We aimed to determine the effect of calcification on ischaemia-driven angiogenesis. Human coronary artery endothelial cells (ECs) were treated with calcification medium (CM: CaCl₂ 2.7 mM, Na₂PO₄ 2.0 mM) for 24 h and exposed to normoxia (5% CO₂) or hypoxia (1.2% O₂; 5% CO₂ balanced with N₂). In normoxia, CM significantly inhibited tubule formation and migration and upregulated calcification markers of ALP, BMP2, and Runx2. CM elevated levels of calcification-protective gene OPG, demonstrating a compensatory mechanism by ECs. CM failed to induce pro-angiogenic regulators VEGFA and HIF-1α in hypoxia and further suppressed the phosphorylation of endothelial nitric oxide synthase (eNOS) that is essential for vascular function. In vivo, osteoprotegerin-deficient mice (OPG^−/−), a calcification model, were subjected to hind-limb ischaemia (HLI) surgery. OPG^−/− mice displayed elevated serum alkaline phosphatase (ALP) activity compared to wild-type controls. OPG^−/− mice experienced striking reductions in blood-flow reperfusion in both 8-week-old and 6-month-old mice post-HLI. This coincided with significant impairment in tissue ischaemia and reduced limb function as assessed by clinical scoring (Tarlov). This study demonstrated for the first time that a pro-calcific environment is detrimental to ischaemia-driven angiogenesis. The degree of calcification in patients with PAD can often be a limiting factor with the use of standard therapies. These highly novel findings require further studies for full elucidation of the mechanisms involved and have implications for the development of therapies to suppress calcification in PAD.

Screen-detected abnormal ankle brachial index: A risk indicator for future cardiovascular morbidity and mortality in patients with manifest cardiovascular disease

Objectives

The ankle brachial index (ABI) can be used to diagnose peripheral arterial disease (PAD). The clinical relevance of the ABI, especially in patients with known clinically manifest cardiovascular disease (CVD), is unknown. The authors set out to investigate the relationship between a screen-detected ABI and the risk for future cardiovascular morbidity and mortality in patients with clinically manifest CVD.

Design, materials and methods

Patients with clinically manifest CVD were selected from the UCC-SMART cohort (n = 8360) and divided into four groups: normal ABI (0.91–1.39), screen-detected low ABI ≤ 0.9, screen-detected high ABI ≥ 1.4, and patients with known PAD irrespective of their ABI. Adjusted Cox Proportional Hazard Ratios (HRs) for Major Adverse Cardiovascular Events (MACE), Major Adverse Limb Events (MALE), and all-cause mortality were calculated. In addition, stratified analyses for women and men and for the presence of diabetes were performed.

Results

During a median follow-up of 8.3 years (IQR 7.7) 1646 MACE, 601 MALE and 1958 all-cause mortalities were observed. Compared with normal ABI patients, patients with a screen-detected low ABI and patients with manifest PAD had a higher risk of MACE, MALE, and all-cause mortality with HRs of 1.9 (95% CI 1.6–2.2) for MACE, 7.6 (95% CI 5.7–10.1) for MALE, 1.7 (95% CI 1.5–2.0) for mortality and 1.3 (95% CI 1.2–1.5) for MACE, 13.8 (95% CI 11.1–17.1) for MALE, 1.7 (95% CI 1.5–1.9) for mortality, respectively. Screen-detected high ABI did not increase the risk of either MACE or MALE, however, was associated with lower risk of all-cause mortality with a HR of 0.6 (95% CI 0.5–0.9). Stratified analyses for women & men and for diabetes status were comparable for all three outcomes.

Conclusions

In patients with manifest CVD but without PAD, a screen-detected low ABI is a powerful risk indicator for cardiovascular events, limb events, and all-cause mortality.

Oxidative Stress Related to Plasmalemmal and Mitochondrial Phosphate Transporters in Vascular Calcification

Inorganic phosphate (Pi) is essential for maintaining cellular function but excess of Pi leads to serious complications, including vascular calcification. Accumulating evidence suggests that oxidative stress contributes to the pathogenic progression of calcific changes. However, the molecular mechanism underlying Pi-induced reactive oxygen species (ROS) generation and its detrimental consequences remain unclear. Type III Na⁺-dependent Pi cotransporter, PiT-1/-2, play a significant role in Pi uptake of vascular smooth muscle cells. Pi influx via PiT-1/-2 increases the abundance of PiT-1/-2 and depolarization-activated Ca²⁺ entry due to its electrogenic properties, which may lead to Ca²⁺ and Pi overload and oxidative stress. At least four mitochondrial Pi transporters are suggested, among which the phosphate carrier (PiC) is known to be mainly involved in mitochondrial Pi uptake. Pi transport via PiC may induce hyperpolarization and superoxide generation, which may lead to mitochondrial dysfunction and endoplasmic reticulum stress, together with generation of cytosolic ROS. Increase in net influx of Ca²⁺ and Pi and their accumulation in the cytosol and mitochondrial matrix synergistically increases oxidative stress and osteogenic differentiation, which could be prevented by suppressing either Ca²⁺ or Pi overload. Therapeutic strategies targeting plasmalemmal and mitochondrial Pi transports can protect against Pi-induced oxidative stress and vascular calcification.

Vitamin D and Calcium Supplementation Accelerate Vascular Calcification in a Model of Pseudoxanthoma Elasticum

Arterial calcification is a common feature of pseudoxanthoma elasticum (PXE), a disease characterized by ABCC6 mutations, inducing a deficiency in pyrophosphate, a key inhibitor of calcium phosphate crystallization in arteries.

METHODS

we analyzed whether long-term exposure of Abcc6^-/- mice (a murine model of PXE) to a mild vitamin D supplementation, with or without calcium, would impact the development of vascular calcification. Eight groups of mice (including Abcc6^-/- and wild-type) received vitamin D supplementation every 2 weeks, a calcium-enriched diet alone (calcium in drinking water), both vitamin D supplementation and calcium-enriched diet, or a standard diet (controls) for 6 months. Aorta and kidney artery calcification was assessed by 3D-micro-computed tomography, Optical PhotoThermal IR (OPTIR) spectroscopy, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) and Yasue staining.

RESULTS

at 6 months, although vitamin D and/or calcium did not significantly increase serum calcium levels, vitamin D and calcium supplementation significantly worsened aorta and renal artery calcification in Abcc6^-/- mice.

CONCLUSIONS

vitamin D and/or calcium supplementation accelerate vascular calcification in a murine model of PXE. These results sound a warning regarding the use of these supplementations in PXE patients and, to a larger extent, patients with low systemic pyrophosphate levels.

Asprosin induces vascular endothelial-to-mesenchymal transition in diabetic lower extremity peripheral artery disease

Background

Altered adipokine secretion in dysfunctional adipose tissue facilitates the development of atherosclerotic diseases including lower extremity peripheral artery disease (PAD). Asprosin is a recently identified adipokine and displays potent regulatory role in metabolism, but the relationship between asprosin and lower extremity PAD remains uninvestigated.

Methods

33 type 2 diabetes mellitus (T2DM) patients (DM), 51 T2DM patients with PAD (DM + PAD) and 30 healthy normal control (NC) volunteers were recruited and the blood samples were collected for detecting the circulatory asprosin level and metabolomic screening. RNA sequencing was performed using the aorta tissues from the type 2 diabetic db/db mice and human umbilical vein endothelial cells (HUVECs) were treated with asprosin to determine its impact on the endothelial-to-mesenchymal transition (EndMT).

Results

The circulating levels of asprosin in DM + PAD group were significantly higher than that of NC group and the DM group. Circulating asprosin level was remarkably negatively correlated with ankle-brachial index (ABI), even after adjusting for age, sex, body mass index (BMI) and other traditional risk factors of PAD. Logistic regression analysis revealed that asprosin is an independent risk factor for PAD and receiver-operator characteristic (ROC) curve determined a good sensitivity (74.5%) and specificity (74.6%) of asprosin to distinguish PAD. Data from metabolomics displayed a typical characteristics of de novo amino acid synthesis in collagen protein production by myofibroblasts in patients with PAD and activation of TGF-β signaling pathway appeared in the aortic tissue of db/db mice. Asprosin directly induces EndMT in HUVECs in a TGF-β-dependent manner as TGF-β signaling pathway inhibitor SB431542 erased the promotional effect of asprosin on EndMT.

Conclusions

Elevated circulatory asprosin level is an independent risk factor of lower extremity PAD and might serve as a diagnostic marker. Mechanistically, asprosin directly induces EndMT that participates in vascular injury via activation of TGF-β signaling pathway.

Trial registration This trial was registered at clinicaltrials.gov as NCT05068895

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01457-0.

Epigenetics of single-site and multi-site atherosclerosis in African Americans from the Genetic Epidemiology Network of Arteriopathy (GENOA)

BACKGROUND

DNA methylation, an epigenetic mechanism modulated by lifestyle and environmental factors, may be an important biomarker of complex diseases including cardiovascular diseases (CVD) and subclinical atherosclerosis.

METHODS

DNA methylation in peripheral blood samples from 391 African-Americans from the Genetic Epidemiology Network of Arteriopathy (GENOA) was assessed at baseline, and atherosclerosis was assessed 5 and 12 years later. Using linear mixed models, we examined the association between previously identified CpGs for coronary artery calcification (CAC) and carotid plaque, both individually and aggregated into methylation risk scores (MRSCAC and MRScarotid), and four measures of atherosclerosis (CAC, abdominal aorta calcification (AAC), ankle-brachial index (ABI), and multi-site atherosclerosis based on gender-specific quartiles of the single-site measures). We also examined the association between four epigenetic age acceleration measures (IEAA, EEAA, PhenoAge acceleration, and GrimAge acceleration) and the four atherosclerosis measures. Finally, we characterized the temporal stability of the epigenetic measures using repeated DNA methylation measured 5 years after baseline (N = 193).

RESULTS

After adjusting for CVD risk factors, four CpGs (cg05575921(AHRR), cg09935388 (GFI1), cg21161138 (AHRR), and cg18168448 (LRRC52)) were associated with multi-site atherosclerosis (FDR < 0.1). cg05575921 was also associated with AAC and cg09935388 with ABI. MRSCAC was associated with ABI (Beta = 0.016, P = 0.006), and MRScarotid was associated with both AAC (Beta = 0.605, equivalent to approximately 1.8-fold increase in the Agatston score of AAC, P = 0.004) and multi-site atherosclerosis (Beta = 0.691, P = 0.002). A 5-year increase in GrimAge acceleration (~ 1 SD) was associated with a 1.6-fold (P = 0.012) increase in the Agatston score of AAC and 0.7 units (P = 0.0003) increase in multi-site atherosclerosis, all after adjusting for CVD risk factors. All epigenetic measures were relatively stable over 5 years, with the highest intraclass correlation coefficients observed for MRScarotid and GrimAge acceleration (0.87 and 0.89, respectively).

CONCLUSIONS

We found evidence of an association between DNA methylation and atherosclerosis at multiple vascular sites in a sample of African-Americans. Further evaluation of these potential biomarkers is warranted to deepen our understanding of the relationship between epigenetics and atherosclerosis.

The Impact of Diabetes on Vascular Disease: Progress from the Perspective of Epidemics and Treatments

At present, the global incidence of diabetes has increased in countries with large populations, and the changes in developing regions are particularly worthy of attention. In the past 40 years or so, the income situation in China, India, and other countries has exploded, leading to changes in the way of life and work as well as an increase in the prevalence of diabetes. Metabolic disorders caused by diabetes can lead to secondary vascular complications, which have long-term malignant effects on the heart, kidneys, brain, and other vital organs of patients. Adequate primary prevention measures are needed to reduce the incidence of diabetic vascular complications, and more attention should be given to treatment after the disease. To this end, it is necessary to determine a standardized drug and physical therapy system and to build a more efficient and low-cost chronic disease management system.