TNFRSF11B gene polymorphisms increased risk of peripheral arterial occlusive disease and critical limb ischemia in patients with type 2 diabetes

Current Medical Therapy and Revascularization in Peripheral Artery Disease of the Lower Limbs: Impacts on Subclinical Chronic Inflammation

Peripheral artery disease (PAD), coronary artery disease (CAD), and cerebrovascular disease (CeVD) are characterized by atherosclerosis and inflammation as their underlying mechanisms. This paper aims to conduct a literature review on pharmacotherapy for PAD, specifically focusing on how different drug classes target pro-inflammatory pathways. The goal is to enhance the choice of therapeutic plans by considering their impact on the chronic subclinical inflammation that is associated with PAD development and progression. We conducted a comprehensive review of currently published original articles, narratives, systematic reviews, and meta-analyses. The aim was to explore the relationship between PAD and inflammation and evaluate the influence of current pharmacological and nonpharmacological interventions on the underlying chronic subclinical inflammation. Our findings indicate that the existing treatments have added anti-inflammatory properties that can potentially delay or prevent PAD progression and improve outcomes, independent of their effects on traditional risk factors. Although inflammation-targeted therapy in PAD shows promising potential, its benefits have not been definitively proven yet. However, it is crucial not to overlook the pleiotropic properties of the currently available treatments, as they may provide valuable insights for therapeutic strategies. Further studies focusing on the anti-inflammatory and immunomodulatory effects of these treatments could enhance our understanding of the mechanisms contributing to the residual risk in PAD and pave the way for the development of novel therapies.

Development of a biomarker panel for assessing cardiovascular risk in diabetic patients with chronic limb-threatening ischemia (CLTI): a prospective study

BACKGROUND

Lower-extremity endovascular revascularization (LER) is often required for diabetic patients with chronic limb threatening ischemia (CLTI). During the post-revascularization period patients may unpredictably experience major adverse cardiac events (MACE) and major adverse limb events (MALE). Several families of cytokines are involved in the inflammatory process that underlies the progression of atherosclerosis. According to current evidence, we have identified a panel of possible biomarkers related with the risk of developing MACE and MALE after LER. The aim was to study the relationship between a panel of biomarkers - Interleukin-1 (IL-1) and 6 (IL-6), C-Reactive Protein (CRP), Tumor Necrosis Factor-α (TNF-α), High-Mobility Group Box-1 (HMGB-1), Osteoprotegerin (OPG), Sortilin and Omentin-1- at baseline, with cardiovascular outcomes (MACE and MALE) after LER in diabetic patients with CLTI.

METHODS

In this prospective non-randomized study, 264 diabetic patients with CLTI undergoing endovascular revascularization were enrolled. Serum levels of each biomarker were collected before revascularization and outcomes' incidence was evaluated after 1, 3, 6 and 12 months.

RESULTS

During the follow-up period, 42 cases of MACE and 81 cases of MALE occurred. There was a linear association for each biomarker at baseline and incident MACE and MALE, except Omentin-1 levels that were inversely related to the presence of MACE or MALE. After adjusting for traditional cardiovascular risk factors, the association between each biomarker baseline level and outcomes remained significant in multivariable analysis. Receiver operating characteristics (ROC) models were constructed using traditional clinical and laboratory risk factors and the inclusion of biomarkers significantly improved the prediction of incident events.

CONCLUSIONS

Elevated IL-1, IL-6, CRP, TNF-α, HMGB-1, OPG and Sortilin levels and low Omentin-1 levels at baseline correlate with worse vascular outcomes in diabetic patients with CLTI undergoing LER. Assessment of the inflammatory state with this panel of biomarkers may support physicians to identify a subset of patients more susceptible to the procedure failure and to develop cardiovascular adverse events after LER.

Markers of Restenosis after Percutaneous Transluminal Balloon Angioplasty in Patients with Critical Limb Ischemia

Among cardiovascular diseases, chronic obliterating lesions of the arteries of lower extremities, which are one of the important problems of modern healthcare, are distinguished. In most cases, the cause of damage to the arteries of lower extremities is atherosclerosis. The most severe form is chronic ischemia, characterized by pain at rest and ischemic ulcers, ultimately increasing the risk of limb loss and cardiovascular mortality. Therefore, patients with critical limb ischemia need limb revascularization. Percutaneous transluminal balloon angioplasty is one of the least invasive and safe approaches, with advantages for patients with comorbidities. However, after this procedure, restenosis is still possible. Early detection of changes in the composition of some molecules as markers of restenosis will help screen patients at the risk of restenosis, as well as find ways to apply efforts for further directions of inhibition of this process. The purpose of this review is to provide the most important and up-to-date information on the mechanisms of restenosis development, as well as possible predictors of their occurrence. The information collected in this publication may be useful in predicting outcomes after surgical treatment and will also find new ways for the target implication to the mechanisms of development of restenosis and atherosclerosis.

Dietary Risk Factors and Eating Behaviors in Peripheral Arterial Disease (PAD)

Dietary risk factors play a fundamental role in the prevention and progression of atherosclerosis and PAD (Peripheral Arterial Disease). The impact of nutrition, however, defined as the process of taking in food and using it for growth, metabolism and repair, remains undefined with regard to PAD. This article describes the interplay between nutrition and the development/progression of PAD. We reviewed 688 articles, including key articles, narrative and systematic reviews, meta-analyses and clinical studies. We analyzed the interaction between nutrition and PAD predictors, and subsequently created four descriptive tables to summarize the relationship between PAD, dietary risk factors and outcomes. We comprehensively reviewed the role of well-studied diets (Mediterranean, vegetarian/vegan, low-carbohydrate ketogenic and intermittent fasting diet) and prevalent eating behaviors (emotional and binge eating, night eating and sleeping disorders, anorexia, bulimia, skipping meals, home cooking and fast/ultra-processed food consumption) on the traditional risk factors of PAD. Moreover, we analyzed the interplay between PAD and nutritional status, nutrients, dietary patterns and eating habits. Dietary patterns and eating disorders affect the development and progression of PAD, as well as its disabling complications including major adverse cardiovascular events (MACE) and major adverse limb events (MALE). Nutrition and dietary risk factor modification are important targets to reduce the risk of PAD as well as the subsequent development of MACE and MALE.

Statins in High Cardiovascular Risk Patients: Do Comorbidities and Characteristics Matter?

Atherosclerotic cardiovascular disease (ASCVD) morbidity and mortality are decreasing in high-income countries, but ASCVD remains the leading cause of morbidity and mortality in high-income countries. Over the past few decades, major risk factors for ASCVD, including LDL cholesterol (LDL-C), have been identified. Statins are the drug of choice for patients at increased risk of ASCVD and remain one of the most commonly used and effective drugs for reducing LDL cholesterol and the risk of mortality and coronary artery disease in high-risk groups. Unfortunately, doctors tend to under-prescribe or under-dose these drugs, mostly out of fear of side effects. The latest guidelines emphasize that treatment intensity should increase with increasing cardiovascular risk and that the decision to initiate intervention remains a matter of individual consideration and shared decision-making. The purpose of this review was to analyze the indications for initiation or continuation of statin therapy in different categories of patient with high cardiovascular risk, considering their complexity and comorbidities in order to personalize treatment.

Factors Influencing the Risk of Major Amputation in Patients with Diabetic Foot Ulcers Treated by Autologous Cell Therapy

INTRODUCTION

Autologous cell therapy (ACT) is one of the last options for limb salvage in patients with chronic limb-threatening ischemia (CLTI) and diabetic foot ulcers (DFU). However, some patients may still undergo a major amputation even after ACT, but the risk factors for this are not known. Therefore, the aim of our study was to assess the risk factors for major amputation in patients with CLTI and DFU during a 2-year follow-up after ACT.

METHODS

One hundred and thirteen patients after ACT were included in our study and divided into two groups: Group 1 with major amputation (AMP; n = 37) and Group 2 without amputation (nAMP, n = 76). The risk factors for major amputation were evaluated before ACT and included factors relating to the patient, the DFU, and the cell product.

RESULTS

The AMP group had significantly higher C-reactive protein (CRP) levels compared to the nAMP group (22.7 vs. 10.7 mg/L, p = 0.024). In stepwise logistic regression, independent predictors for major amputation were mutation of the gene for methylenetetrahydrofolate reductase (MTHFR) with heterozygote and homozygote polymorphism 1298 (OR 4.33 [95% CI 1.05-17.6]), smoking (OR 3.83 [95% CI 1.18-12.5]), and CRP > 10 mg/L (OR 2.76 [95% CI 0.93-8.21]). Lower transcutaneous oxygen pressure (TcPO₂) values were observed in AMP patients compared to the nAMP group at one month (24.5 vs. 33.2, p = 0.012) and at 3 months (31.1 vs. 40.9, p = 0.009) after ACT.

CONCLUSION

Our study showed that the risk for major amputation after ACT in patients with CLTI and DFU is increased by the presence of MTHFR heterozygote and homozygote gene mutations, smoking, and higher CRP at baseline. Lower TcPO₂ at one and 3 months after ACT may also have a predictive value. Therefore, it is necessary to stop smoking before ACT, treat any infection, and, above all, consider antiaggregation or anticoagulant treatment after the procedure.

Principal predictors of major adverse limb events in diabetic peripheral artery disease: A narrative review

Background and aims

The increasing prevalence of diabetes mellitus is causing a massive growth of peripheral artery disease incidences, a disabling complication of diabetic atherosclerosis, which leads often to the amputation of the affected limb. Critical limb ischemia is the terminal disease stage, which requires a prompt intervention to relieve pain and save limbs. However, patients undergoing revascularization often suffer from cardiovascular, cerebrovascular and major adverse limb events with poor outcomes. Furthermore, the same procedure performed in apparently similar patients has various outcomes and lack of an outcome predictive support causes a high lower limb arterial revascularization rate with disastrous effects for patients. We collected the main risk factors of major adverse limb events in a more readable and immediate format of the topic, to propose an overview of parameters to manage effectively peripheral artery disease patients and to propose basics of a new predictive tool to prevent from disabling vascular complications of the disease.

Methods

Most recent and updated literature about the prevalence of major adverse limb events in peripheral artery disease was reviewed to identify possible main predictors.

Results

In this article, we summarized major risk factors of limb revascularization failure and disabling vascular complications collecting those parameters principally responsible for major adverse limb events, which provides physio-pathological explanation of their role in peripheral artery disease.

Conclusion

We evaluated and listed a panel of possible predictors of MALE (Major Adverse Limb Event) in order to contribute to the development of a predictive score, based on a summary of the main risk factors reported in scientific articles, which could improve the management of peripheral artery disease by preventing vascular accidents.

Association between carotid plaque vulnerability and high mobility group box-1 serum levels in a diabetic population

Background

Carotid atherosclerosis represents one of the complications of diabetes mellitus. In particular, plaque instability contributes to disease progression and stroke incidence. High mobility group box-1 (HMGB1) is a nuclear protein involved in promotion and progression of atherosclerosis and cardiovascular diseases. The aim of this study was to analyze the relationship between HMGB1 serum levels, main inflammatory cytokines, the presence of internal carotid stenosis and unstable plaque in a diabetic population.

Research design and methods

We studied 873 diabetic patients, including 347 patients with internal carotid artery stenosis (ICAS) who underwent carotid endarterectomy and 526 diabetic patients without internal carotid artery stenosis (WICAS). At baseline, HMGB1 and the main inflammatory cytokines serum levels were evaluated. For ICAS patients, the histological features of carotid plaque were also collected to differentiate them in patients with stable or unstable atherosclerotic lesions.

Results

We found that HMGB1 serum levels, osteoprotegerin, high-sensitivity C-reactive protein, tumor necrosis factor-alpha and interleukin-6, were significantly higher in diabetic ICAS patients compared to diabetic WICAS patients. Among ICAS patients, individuals with unstable plaque had higher levels of these cytokines, compared to patients with stable plaque. A multivariable stepwise logistic regression analysis showed that HMGB1 and osteoprotegerin remained independently associated with unstable plaque in ICAS patients.

Conclusions

The present study demonstrated that HMGB1 is an independent risk factor for carotid plaque vulnerability in an Italian population with diabetes mellitus, representing a promising biomarker of carotid plaque instability and a possible molecular target to treat unstable carotid plaques and to prevent stroke.

Outcomes of Lower Extremity Endovascular Revascularization: Potential Predictors and Prevention Strategies

Peripheral artery disease (PAD) is a manifestation of atherosclerosis, which may affect arteries of the lower extremities. The most dangerous PAD complication is chronic limb-threatening ischemia (CLTI). Without revascularization, CLTI often causes limb loss. However, neither open surgical revascularization nor endovascular treatment (EVT) ensure long-term success and freedom from restenosis and revascularization failure. In recent years, EVT has gained growing acceptance among all vascular specialties, becoming the primary approach of revascularization in patients with CLTI. In clinical practice, different clinical outcomes after EVT in patients with similar comorbidities undergoing the same procedure (in terms of revascularization technique and localization of the disease) cause unsolved issues that need to be addressed. Nowadays, risk management of revascularization failure is one of the major challenges in the vascular field. The aim of this literature review is to identify potential predictors for lower extremity endovascular revascularization outcomes and possible prevention strategies.

Association Between Metabolic Syndrome and Peripheral Arterial Disease in Elderly Patients with Type 2 Diabetes

BACKGROUND

Peripheral artery disease (PAD) is a manifestation of atherosclerotic cardiovascular disease (ASCVD) and significantly increases the risk of myocardial infarction and stroke. As most patients with PAD are asymptomatic, this condition is largely neglected in clinical practice. Type 2 diabetes (T2DM) patients have higher prevalence of PAD. Therefore, early detection and intervention of diabetic PAD are very important. Metabolic syndrome (MetS) is a group of interrelated metabolic risk factors, a predictor of poor prognosis in elderly patients with ASCVD. Recently, many of the metabolic risk factors as well as the overall concept of MetS itself have sparked a great deal of debate regarding their precise roles in PAD.

OBJECTIVE

To evaluate the relationship between metabolic syndrome (MetS) and peripheral arterial disease (PAD) in elderly patients with type 2 diabetes (T2DM).

METHODS

Two hundred and eighty-one elderly T2DM patients admitted to Beijing Tongren Hospital from October 2016 to December 2017 were divided into PAD group (n=136) and non-PAD (NPAD) group (n=145). Their medical records, physical examination parameters and laboratory testing parameters were later recorded and analyzed by multivariate logistic regression analysis.

RESULTS

No significant difference was detected in general clinical data and laboratory testing parameters between the two groups (P>0.05). The incidence of MetS was significantly higher in PAD group than in NPAD group (88.2% vs 70.3%, P=0.001). Multivariate logistic regression analysis showed that the risk of PAD was 1.762-fold higher in MetS patients after adjustment for age, sex, history of smoking and alcohol consumption, WC, SBP, serum TC and HbA1c level, eGFR and duration of DM (95% CI: 1.205-6.330, P=0.016).

CONCLUSION

MetS closely correlates with PAD in elderly T2DM patients, though no significant difference has been detected in their metabolic indicators.

Association between omentin-1 and major cardiovascular events after lower extremity endovascular revascularization in diabetic patients: a prospective cohort study

Background

Cardiovascular complications represent the major cause of morbidity and mortality of type 2 diabetes mellitus (T2DM) patients. In particular, peripheral artery disease (PAD) represents a frequent T2DM vascular complication and a risk factor for the development of major adverse cardiovascular events (MACE). Among adipokines, omentin-1 serum levels are reduced in T2DM patients with PAD and are inversely related to disease severity.

Objective

To study the relationship between omentin-1 levels, at baseline, with outcomes after endovascular procedures in T2DM patients with PAD and chronic limb-threatening ischemia (CLTI).

Research design and methods

We enrolled for our prospective non-randomized study, 207 T2DM patients with PAD and CLTI, requiring revascularization. Omentin-1 serum levels were collected before revascularization and patients incidence outcomes were evaluated at 1, 3, 6 and 12 months.

Results

Omentin-1 was reduced in patients with more severe disease (27.24 ± 4.83 vs 30.82 ± 5.48 ng/mL, p < 0.001). Overall, 84 MACE and 96 major adverse limb events (MALE) occurred during the 12-month follow-up. We observed that omentin-1 levels were lower in patients with MACE (26.02 ± 4.05 vs 31.33 ± 5.29 ng/mL, p < 0.001) and MALE (26.67 ± 4.21 vs 31.34 ± 5.54 ng/mL, p < 0.001). The association between omentin-1, MACE and MALE remained significant after adjusting for major risk factors in a multivariate analysis. Receiver operating characteristics (ROC) curve using omentin-1 levels predicted incidence events (area under the curve = 0.80).

Conclusions

We demonstrated that reduced omentin-1 levels, at baseline, are related with worse vascular outcomes in T2DM patients with PAD and CLTI undergoing an endovascular procedure.

TNFRSF11B polymorphisms predict poor outcome after large artery atherosclerosis stroke

Osteoprotegerin is involved in the progression of atherosclerosis. This study aimed to determine whether TNFRSF11B polymorphisms are associated with prognosis of large artery atherosclerosis (LAA) stroke. Three TNFRSF11B polymorphisms (rs2073617, rs2073618 and rs3134069) were genotyped in 1010 patients with LAA stroke. Short-term outcome was evaluated using the modified Rankin Scale score at 3-month after stroke onset. Long-term outcome was assessed using the stroke recurrence. We found that rs2073617G was associated with an increased risk of poor outcome of LAA stroke (additive model: odds ratio (OR) = 1.35, 95% confidence interval (CI) = 1.06-1.73). This association was also observed in rs3134069C (additive model: OR = 1.53, 95% CI = 1.10-2.12). Furthermore, when we combined these two polymorphisms according to the numbers of risk alleles (rs2073617G and rs3134069C), we found that the patients with 3-4 risk alleles were statistically significantly associated with an increased risk of poor outcome of LAA stroke (OR = 1.90, 95% CI = 1.10-3.28) compared with 0-2 risk alleles, and this increased risk was more evident among those with hypertension (OR = 2.02, 95% CI = 1.04-3.91), those without diabetes (OR = 2.02, 95% CI = 1.02-4.01) and those with smoking (OR = 2.43, 95% CI = 1.09-5.42). In silico analysis showed that rs2073617 and rs3134069 are located in various histone modification marked regions, DNase I hypersensitive sites and can change the binding of regulatory motifs. Moreover, rs2073617 is also located in the binding site of transcription factors. Our findings suggested that TNFRSF11B polymorphisms may be associated with an increased risk of short-term poor outcome of LAA stroke.

High Mobility Group Box-1 and Diabetes Mellitus Complications: State of the Art and Future Perspectives

Diabetes mellitus (DM) is an endemic disease, with growing health and social costs. The complications of diabetes can affect potentially all parts of the human body, from the heart to the kidneys, peripheral and central nervous system, and the vascular bed. Although many mechanisms have been studied, not all players responsible for these complications have been defined yet. High Mobility Group Box-1 (HMGB1) is a non-histone nuclear protein that has been implicated in many pathological processes, from sepsis to ischemia. The purpose of this review is to take stock of all the most recent data available on the role of HMGB1 in the complications of DM.

Inflammatory Cytokines Associated With Failure of Lower-Extremity Endovascular Revascularization (LER): A Prospective Study of a Population With Diabetes

OBJECTIVE

Peripheral artery disease (PAD) is one of the most relevant complications of diabetes. Although several pharmacological and revascularization approaches are available for treating patients with diabetes and PAD, an endovascular approach is often associated with postprocedural complications that can increase the risk for acute limb ischemia or amputation. However, no definitive molecular associations have been described that could explain the difference in outcomes after endovascular treatment in patients with diabetes, PAD, and chronic limb-threatening ischemia (CLTI).

RESEARCH DESIGN AND METHODS

We evaluated the relationship between the levels of the main cytokines associated with diabetic atherosclerosis and the outcomes after endovascular procedures in patients with diabetes, PAD, and CLTI.

RESULTS

A total of 299 patients with below-the-knee occlusive disease who were undergoing an angioplasty procedure were enrolled. The levels of key cytokines-osteoprotegerin (OPG), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and C-reactive protein (CRP)-were measured, and major adverse limb events (MALE) and major adverse cardiovascular events (MACE) were assessed 1, 3, 6, and 12 months after the procedure. There was a linear trend from the lowest to the highest quartile for each cytokine at baseline and incident MALE. A linear association was also observed between increasing levels of each cytokine and incident MACE. Receiver operating characteristics models were constructed using clinical and laboratory risk factors, and the inclusion of cytokines significantly improved the prediction of incident events.

CONCLUSIONS

We demonstrated that elevated OPG, TNF-α, IL-6, and CRP levels at baseline correlate with worse vascular outcomes in patients with diabetes, PAD, and CLTI undergoing an endovascular procedure.

The Role of the Microbiota in the Diabetic Peripheral Artery Disease

Vascular complications of diabetes mellitus represent a major public health problem. Although many steps forward have been made to define the causes and to find the best possible therapies, the problem remains crucial. In recent years, more and more evidences have defined a link between microbiota and the initiation, promotion, and evolution of atherosclerotic disease, even in the diabetic scenario. There is an urgency to develop the knowledge of modern medicine about the link between gut microbiota and its host's metabolic pathways, and it would be useful to understand and justify the interindividual diversity of clinical disease presentation of diabetic vascular complication even if an optimization of pharmacological treatment has been made or in the case of young patients where hypertension, dyslipidemia, and diabetes are not able to justify a very quick progress of atherosclerotic process. The aim of the present review is to gather all the best available evidence in this regard and to define a new role of the microbiota in this field, from biomarker to possible therapeutic target.

The Emerging Role of Bone Markers in Diagnosis and Risk Stratification of Patients With Coronary Artery Disease

Molecules that govern bone metabolism, such as osteoprotegerin (OPG) and osteopontin (OPN), have been isolated from other tissues, including blood vessels. Atherosclerosis and coronary artery disease (CAD) are leading causes of mortality worldwide. Despite novel biochemical and imaging techniques, early detection of CAD is still unsatisfactory. Experimental data indicate that bone turnover markers (BTMs) contribute to the development of atherosclerosis. This finding has sparked interest in their clinical use. This narrative review analyzed information from >50 human studies, which strongly suggest that OPG, OPN, and alkaline phosphatase (ALP) serum concentrations are altered in patients with CAD. Osteoprotegerin seems to be more useful for the detection of early disease, while OPN and ALP are recruited in vessels after the establishment of disease. Osteocalcin may be used as a flow cytometry marker for endothelial progenitor cells and can constitute a marker to monitor response to interventional treatments and risk of restenosis. However, most data derive from observational studies. Incorporation of BTMs in multifactorial computational algorithms could further determine their role in CAD diagnosis and prognosis together with other imaging techniques and biochemical markers.

Osteoprotegerin concentration is associated with the presence and severity of peripheral arterial disease in type 2 diabetes mellitus

BACKGROUND

Osteoprotegerin plays a role in the development of several bone diseases. In addition, osteoprotegerin may contribute to the development of vascular disease. Little is known about the association between serum osteoprotegerin levels and the presence or severity of peripheral arterial disease (PAD). The aim of this study was to examine the association between serum osteoprotegerin levels and both the presence as well as the severity of lower extremity arterial disease in patients with type 2 diabetes (T2DM).

PATIENTS AND METHODS

The study included 165 consecutive patients with T2DM (57 % males, mean age 65.0 ± 0.7 years). PAD was diagnosed by measurement of the toe-brachial index (TBI). Serum osteoprotegerin was measured using ELISA.

RESULTS

The mean osteoprotegerin level was significantly higher in patients with PAD in comparison to patients without PAD (18.2 ± 1.0 vs. 13.1 ± 2.0 pmol/L, p = 0.014). Significant univariate correlations between TBI and osteoprotegerin level (r = -0.308; p < 0.001), age, body mass index, and HDL cholesterol were observed. In the multivariate linear regression analysis, serum osteoprotegerin (β = -0.005; p = 0.020), higher age, and male gender were significant predictors of TBI. When 25(OH) vitamin D was introduced into the mentioned model, OPG was no longer a significant predictor of TBI and was replaced in the model with vitamin D (β = 0.009, p = 0.001). This finding suggests a role of OPG as a mediator of the effects of 25(OH) vitamin D.

CONCLUSIONS

Serum osteoprotegerin level is significantly associated with both the presence and severity of PAD in patients with T2D. Osteoprotegerin might be a biomarker for the presence of atherosclerotic disease in patients with T2DM.

Peripheral Arterial Disease Genetics: Progress to Date and Challenges Ahead

PURPOSE OF REVIEW

In this paper, we review the progress made thus far in research related to the genetics of peripheral arterial disease (PAD) by detailing efforts to date in heritability, linkage analyses, and candidate gene studies. We further summarize more contemporary genome-wide association studies (GWAS) and epigenetic studies of PAD. Finally, we review current challenges and future avenues of advanced research in PAD genetics including whole genome sequencing studies.

RECENT FINDINGS

Studies have estimated the heritability of PAD to be moderate, though the contribution to this heritability that is independent of traditional cardiovascular risk factors remains unclear. Recent efforts have identified SNPs associated with PAD in GWAS analyses, but these have yet to be replicated in independent studies. Much remains to be discovered in the field of PAD genetics. An improved understanding of the genetic foundation for PAD will allow for earlier diagnosis of disease and a more complete pathophysiological understanding of the mechanisms of the disease leading to novel therapeutic interventions. Future avenues for success will likely arise from very large-scale GWAS, whole genome sequencing, and epigenetic studies involving very well-characterized cohorts.

Mendelian Randomization Analyses for Selection of Therapeutic Targets for Cardiovascular Disease Prevention: a Note of Circumspection

Genetic factors identified from genome-wide association studies have been used to understand causative variants for complex diseases. Studies conducted on large populations of individuals from many geographical regions have provided insights into genetic pathways involved in the causal pathway for atherosclerotic cardiovascular disease. A single genetic trait may ineffectively evaluate the pathway of interest, and it may not account for other complementary genetic pathways that may be activated at various stages of the disease process or evidence-based therapies that alter the molecular and cellular milieu.

New semiquantitative ultrasonographic score for peripheral arterial disease assessment and its association with cardiovascular risk factors

The data concerning the distribution, extent and progression of peripheral arterial disease (PAD), as well as its association with traditional cardiovascular (CV) risk factors, have generally been obtained from studies of patients in advanced stages of the disease undergoing surgical or endovascular treatment. In this study, we have introduced a new semiquantitative ultrasonographic score (ultrasonographic lower limb atherosclerosis (ULLA) score) that is able to categorize lower limb atherosclerotic lesions at all stages of PAD. We then associated these ultrasonographic categories with a CV risk profile. We enrolled 320 consecutive subjects with symptoms suggestive of PAD or with known CV risk factors referring to our angiology unit between 1 July 2014 and 30 June 2015 for ultrasonographic evaluation of the lower limb arteries. Femoropopliteal and run-off segments were categorized together and separately based on their ultrasonographic characteristics. In univariate and multivariate analyses, the ULLA scores were significantly associated with the main CV risk factors, that is, age, male gender, cigarette smoking, arterial hypertension, diabetes, dyslipidemia, sedentary lifestyle, previous CV events and family history of CV disease, and also confirming the specific association of single risk factors with different segments of lower limb arteries. The proposed ULLA score enables a complete evaluation of the entire lower limb atherosclerotic burden, extending the results concerning the association of PAD with CV risk factors to all stages of the disease, including the early stages. It can be feasible that this new score will facilitate better evaluation of the progression of PAD and its prospective role in CV risk stratification.

OPG rs2073617 polymorphism is associated with upregulated OPG protein expression and an increased risk of intervertebral disc degeneration

The present study aimed to investigate the associations between three distinct osteoprotegerin (OPG) gene polymorphisms and the risk of intervertebral disc degeneration (IDD). A total of 200 IDD patients and 200 healthy controls were recruited from the Department of Spine Surgery at the First Affiliated Hospital of the University of South China (Hengyang, China) between January 2013 and May 2014. The allele, genotype and haplotype frequency distributions of three OPG polymorphisms in the study and control populations were analyzed by polymerase chain reaction prior to restriction fragment length polymorphism or high resolution melting assays. In addition, serum OPG levels were measured via an ELISA. The genotype and allele frequencies of the OPG rs2073617 polymorphisms were significantly higher in the IDD patients, as compared with the control group (P<0.05). Furthermore, carriers of the C allele exhibited a higher risk of IDD, as compared with carriers of the T allele (P<0.001). Conversely, the genotype and allele frequencies of the two other gene polymorphisms, rs2073618 and rs3102735, showed no significant differences between the patients and controls (P>0.05). The serum OPG levels were significantly higher in IDD patients with TT, TC and CC genotypes at the OPG rs2073617 polymorphism, as compared with the control group (P<0.05). Logistic-regression analysis suggested that high serum levels of OPG were positively correlated with IDD risk, whereas the T-C-A, T-G-A and T-G-G haplotypes were negatively correlated with IDD risk (P<0.05). Furthermore, the G-T-G haplotype was associated with protection against IDD (P=0.008), whereas the G-C-G haplotype was associated with an elevated susceptibility to IDD (P=0.007). The results of the present study suggested that OPG rs2073617 polymorphisms and upregulated serum levels of OPG were associated with an increased risk of IDD, whereas the T-C-A, T-G-A and T-G-G haplotypes were protective factors for IDD. The results of the present study suggested that the OPG gene polymorphism may have an important role in the progression of IDD, and its serum level may function as a valuable predictive indicator of the severity of degenerative disc diseases.