Project description:BackgroundPeripheral arterial disease (PAD) is a relatively common manifestation of systemic atherosclerosis that leads to progressive narrowing of the lumen of leg arteries. Circulating monocytes are in contact with the arterial wall and can serve as reporters of vascular pathology in the setting of PAD. We performed gene expression analysis of peripheral blood mononuclear cells (PBMC) in patients with PAD and controls without PAD to identify differentially regulated genes.MethodsPAD was defined as an ankle brachial index (ABI) ≤0.9 (n = 19) while age and gender matched controls had an ABI > 1.0 (n = 18). Microarray analysis was performed using Affymetrix HG-U133 plus 2.0 gene chips and analyzed using GeneSpring GX 11.0. Gene expression data was normalized using Robust Multichip Analysis (RMA) normalization method, differential expression was defined as a fold change ≥1.5, followed by unpaired Mann-Whitney test (P < 0.05) and correction for multiple testing by Benjamini and Hochberg False Discovery Rate. Meta-analysis of differentially expressed genes was performed using an integrated bioinformatics pipeline with tools for enrichment analysis using Gene Ontology (GO) terms, pathway analysis using Kyoto Encyclopedia of Genes and Genomes (KEGG), molecular event enrichment using Reactome annotations and network analysis using Ingenuity Pathway Analysis suite. Extensive biocuration was also performed to understand the functional context of genes.ResultsWe identified 87 genes differentially expressed in the setting of PAD; 40 genes were upregulated and 47 genes were downregulated. We employed an integrated bioinformatics pipeline coupled with literature curation to characterize the functional coherence of differentially regulated genes.ConclusionNotably, upregulated genes mediate immune response, inflammation, apoptosis, stress response, phosphorylation, hemostasis, platelet activation and platelet aggregation. Downregulated genes included several genes from the zinc finger family that are involved in transcriptional regulation. These results provide insights into molecular mechanisms relevant to the pathophysiology of PAD.
Project description:Peripheral arterial disease (PAD) is a common vascular disease that reduces blood flow capacity to the legs of patients. PAD leads to exercise intolerance that can progress in severity to greatly limit mobility, and in advanced cases leads to frank ischemia with pain at rest. It is estimated that 12 to 15 million people in the United States are diagnosed with PAD, with a much larger population that is undiagnosed. The presence of PAD predicts a 50% to 1500% increase in morbidity and mortality, depending on severity. Treatment of patients with PAD is limited to modification of cardiovascular disease risk factors, pharmacological intervention, surgery, and exercise therapy. Extended exercise programs that involve walking approximately five times per week, at a significant intensity that requires frequent rest periods, are most significant. Preclinical studies and virtually all clinical trials demonstrate the benefits of exercise therapy, including improved walking tolerance, modified inflammatory/hemostatic markers, enhanced vasoresponsiveness, adaptations within the limb (angiogenesis, arteriogenesis, and mitochondrial synthesis) that enhance oxygen delivery and metabolic responses, potentially delayed progression of the disease, enhanced quality of life indices, and extended longevity. A synthesis is provided as to how these adaptations can develop in the context of our current state of knowledge and events known to be orchestrated by exercise. The benefits are so compelling that exercise prescription should be an essential option presented to patients with PAD in the absence of contraindications. Obviously, selecting for a lifestyle pattern that includes enhanced physical activity prior to the advance of PAD limitations is the most desirable and beneficial.
Project description:Peripheral arterial occlusive disease (PAOD) results from atherosclerosis of large and medium peripheral arteries, as well as the aorta, and has many risk factors, including smoking, diabetes, hypertension, and hyperlipidemia. PAOD often coexists with coronary artery disease and cerebrovascular disease. Cross-matching a population-based list of Icelandic patients with PAOD who had undergone angiography and/or revascularization procedures with a genealogy database of the entire Icelandic nation defined 116 extended families containing 272 patients. A genomewide scan with microsatellite markers revealed significant linkage to chromosome 1p31 with an allele-sharing LOD score of 3.93 (P=1.04 x 10(-5)). We designate this locus as "PAOD1." Subtracting 35 patients with a history of stroke increased the LOD score to 4.93. This suggests that, although PAOD and other vascular diseases share risk factors, genetic factors specific to subtypes of vascular disease may exist.
Project description:Several cell-based therapies for peripheral arterial disease (PAD) have been studied in multiple clinical trials; however, the outcome of this treatment remains controversial. The aim of this study was to perform a meta-analysis of the clinical trials on stem cell-based therapy after PAD. We searched for clinical trials that investigated the effect of stem cell-based therapy on patients with PAD and were published between January 2000 and October 2014. The outcomes of interest comprised all-cause mortality, amputation rate, ulcer healing, and ankle-brachial index (ABI). In addition, pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the safety and efficacy of the stem cell-based therapies for PAD. Thirteen studies were retrieved from 261 citations for the analysis, and in total, 527 patients (mean age: 64.2 years; median follow up: 6 months) were included in the analysis. After synthesizing data, the meta-analysis showed significant improvement in the amputation rate (OR=0.33, 95%CI=0.22-0.51; P<0.001), ulcer healing (OR=6.11, 95%CI=3.04-12.28; P<0.001), and ABI (SMD=0.65, 95%CI=0.33-0.97; P<0.001) for the stem cell-based therapy group compared with the controls. Moreover, significant improvement in the amputation rate, ulcer healing, and ABI were also found based on the time point and stem cell source. In addition, no significant difference was found in the all-cause mortality (OR=0.80, 95%CI=0.39-1.641; P=0.546) between the stem cell-based therapy and control groups. Therefore, according to the results of our meta-analysis, stem cell-based therapy is safe and shows a beneficial outcome for patients with PAD, especially in the short term.
Project description:BackgroundHigh-quality evidence from trials directly comparing single antiplatelet therapies in symptomatic peripheral arterial disease (PAD) to dual antiplatelet therapies or acetylsalicylic acid (ASA) plus low-dose rivaroxaban is lacking. Therefore, we conducted a network meta-analysis on the effectiveness of all antithrombotic regimens studied in PAD.MethodsA systematic search was conducted to identify randomized controlled trials. The primary endpoints were major adverse cardiovascular events (MACE) and major bleedings. Secondary endpoints were major adverse limb events (MALE) and acute limb ischaemia (ALI). For each outcome, a frequentist network meta-analysis was used to compare relative risks (RRs) between medication and ASA. ASA was the universal comparator since a majority of studies used ASA as in the reference group.ResultsTwenty-four randomized controlled trials were identified including 48,759 patients. With regard to reducing MACE, clopidogrel [RR 0.78, 95% confidence interval (CI) 0.66-0.93], ticagrelor (RR 0.79, 95% CI 0.65-0.97), ASA plus ticagrelor (RR 0.79, 95% CI 0.64-0.97), and ASA plus low-dose rivaroxaban (RR 0.84, 95% CI 0.76-0.93) were more effective than ASA, and equally effective to one another. As compared to ASA, major bleedings occurred more frequently with vitamin K antagonists, rivaroxaban, ASA plus vitamin K antagonists, and ASA plus low-dose rivaroxaban. All regimens were similar to ASA concerning MALE, while ASA plus low-dose rivaroxaban was more effective in preventing ALI (RR 0.67, 95% CI 0.55-0.80). Subgroup analysis in patients undergoing peripheral revascularization revealed that ≥ 3 months after intervention, evidence of benefit regarding clopidogrel, ticagrelor, and ASA plus ticagrelor was lacking, while ASA plus low-dose rivaroxaban was more effective in preventing MACE (RR 0.87, 95% CI 0.78-0.97) and MALE (RR 0.89, 95% CI 0.81-0.97) compared to ASA. ASA plus clopidogrel was not superior to ASA in preventing MACE ≥ 3 months after revascularization. Evidence regarding antithrombotic treatment strategies within 3 months after a peripheral intervention was lacking.ConclusionClopidogrel, ticagrelor, ASA plus ticagrelor, and ASA plus low-dose rivaroxaban are superior to ASA monotherapy and equally effective to one another in preventing MACE in PAD. Of these four therapies, only ASA plus low-dose rivaroxaban provides a higher risk of major bleedings. More than 3 months after peripheral vascular intervention, ASA plus low-dose rivaroxaban is superior in preventing MACE and MALE compared to ASA but again at the cost of a higher risk of bleeding, while other treatment regimens show non-superiority. Based on the current evidence, clopidogrel may be considered the antithrombotic therapy of choice for most PAD patients, while in patients who underwent a peripheral vascular intervention, ASA plus low-dose rivaroxaban could be considered for the long-term (> 3 months) prevention of MACE and MALE.
Project description:Peripheral arterial disease is characterized by impaired blood flow to tissues outside the heart due to atherosclerosis and it most frequently occurs in the lower extremities. Type 2 diabetes (T2D) is a well-known risk factor that accelerate the course and contributes to poor clinical outcomes of PAD. While there is some evidence that T2D is associated with altered expression of genes involved in regulating PAD severity, our knowledge about the specific genes and pathways involved remains incomplete. We induced experimental PAD or hind limb ischemia in T2D and non-diabetic mice and subjected the ischemic gastrocnemius muscle tissues to genome-wide mRNA transcriptome analysis. We subsequently performed pathway analysis on the top 500 genes that showed the most significant expression differences between the ischemic diabetic and ischemic non-diabetic muscle tissues. Pathway analysis of the differentially expressed genes identified pathways involved in essential biological processes such as "metabolic pathways," "phagosomes," "lysosomes," and "regulation of actin cytoskeleton". Overall, our data provides the opportunity to test hypotheses on the potential role of the altered genes/molecular pathways in poor PAD outcomes in diabetes.
Project description:Cadmium has been associated with peripheral arterial disease (PAD) in cross-sectional studies, but prospective evidence is lacking. Our goal was to evaluate the association of urine cadmium concentrations with incident PAD in a large population-based cohort.A prospective cohort study was performed with 2864 adult American Indians 45 to 74 years of age from Arizona, Oklahoma, and North and South Dakota who participated in the Strong Heart Study from 1989 to 1991 and were followed through 2 follow-up examination visits in 1993 to 1995 and 1997 to 1999. Participants were free of PAD, defined as an ankle brachial index <0.9 or >1.4 at baseline, and had complete baseline information on urine cadmium, potential confounders, and ankle brachial index determinations in the follow-up examinations. Urine cadmium was measured using inductively coupled plasma mass spectrometry and corrected for urinary dilution by normalization to urine creatinine. Multivariable-adjusted hazard ratios were computed using Cox-proportional hazards models for interval-censored data. A total of 470 cases of incident PAD, defined as an ankle brachial index <0.9 or >1.4, were identified. After adjustment for cardiovascular disease risk factors including smoking status and pack-years, the hazard ratio comparing the 80th to the 20th percentile of urine cadmium concentrations was 1.41 (1.05-1.81). The hazard ratio comparing the highest to the lowest tertile was 1.96 (1.32-2.81). The association persisted after excluding participants with ankle brachial index >1.4 only as well as in subgroups defined by sex and smoking status.Urine cadmium, a biomarker of long-term cadmium exposure, was independently associated with incident PAD, providing further support for cadmium as a cardiovascular disease risk factor.
Project description:BackgroundLittle is known about the extent to which routine care management of peripheral arterial disease (PAD) and intermittent claudication (IC) align with best practice recommendations on exercise therapy. We conducted a scoping review to examine the published literature on the availability and workings of exercise therapy in the routine management of patients with PAD and IC, and the attitude and practice of health professionals and patients.MethodsA systematic search was conducted in February 2018. The Cumulative Index of Nursing and Allied Health Literature, Ovid MEDLINE, Allied and Complementary Medicine Database, ScienceDirect, Web of Science and the Directory of Open Access Repositories were searched. Hand searching of reference lists of identified studies was also performed. Inclusion criteria were based on study aim, and included studies that reported on the perceptions, practices, and workings of routine exercise programs for patients with IC, their availability, access, and perceived barriers.ResultsEight studies met the eligibility criteria and were included in the review. Studies conducted within Europe were included. Findings indicated that vascular surgeons in parts of Europe generally recognize supervised exercise therapy as a best practice treatment for IC, but do not often refer their patients for supervised exercise therapy due to the unavailability of, or lack of access to supervised exercise therapy programs. Available supervised exercise therapy programs do not implement best practice recommendations, and in the majority, patients only undergo one session per week. Some challenges were cited as the cause of the suboptimal program implementation. These included issues related to patients' engagement and adherence as well as resource constraints.ConclusionThere is a dearth of published research on exercise therapy in the routine management of PAD and IC. Available data from a few countries within Europe indicated that supervised exercise is underutilized despite health professionals recognizing the benefits. Research is needed to understand how to improve the availability, access, uptake, and adherence to the best exercise recommendations in the routine management of people with PAD and IC.
Project description:Peripheral arterial disease (PAD) describes the clinical manifestations of atherosclerosis affecting the circulation in the legs. The severity of PAD is classified according to symptom severity, time course, and anatomical distribution. The signs and symptoms of PAD reflect the degree of circulatory compromise and whether there has been a gradual reduction in the circulation or an abrupt, uncompensated decrease. Accurate clinical assessment underpins decisions on management strategy and should objectively assess the severity of the ischemia and need for revascularization. Clinical history should discriminate symptoms of PAD from other conditions presenting with leg pain, elucidate cardiovascular risk factors and the effect of symptoms on the patient's quality of life. Clinical examination includes signs of general cardiovascular disease and associated conditions before assessing the circulation and viability of the limb. Palpation of peripheral pulses must be augmented by determination of the ankle brachial pressure index using hand held Doppler. A whole patient approach to management is required and must include modification of cardiovascular risk status as well as dealing with the local circulatory manifestation of PAD.
Project description:Peripheral artery disease (PAD) is estimated to affect more than 20% of people older than 65 years. The vast majority of patients with symptoms suggestive of PAD have atherosclerosis often associated with conventional vascular risk factors such as smoking, diabetes, dyslipidemia, and inflammation. A minority of people presenting with symptoms suggesting PAD have an alternative etiology. These groups of disorders are often underdiagnosed, and if diagnosed correctly the diagnosis may be delayed. Understanding these pathologies well is important, as they can be very debilitating and optimal treatment may vary significantly. Inappropriate treatment of these disorders can lead to worsening morbidity and mortality. This article discusses the underlying causes of nonatherosclerotic PAD, including the diagnosis and treatment of these disorders.