Factors associated with lack of clinical improvement after vein ablation in the vascular quality initiative.

BACKGROUND: Insurance companies have adopted variable and inconsistent approval criteria for chronic venous disease (CVD) treatment. Although vein ablation (VA) is accepted as the standard of care for venous ulcers, the treatment criteria for patients with milder forms of CVD remain controversial. This study aims to identify factors associated with a lack of clinical improvement (LCI) in patients with less severe CVD without ulceration undergoing VA to improve patient selection for treatment. METHODS: We performed a retrospective analysis of patients undergoing VA for CEAP C2 to C4 disease in the Vascular Quality Initiative varicose veins database from 2014 to 2023. Patients who required intervention in multiple veins, had undergone prior interventions, or presented with CEAP C5 to C6 disease were excluded. The difference (Δ) in venous clinical severity score (VCSS; VCSS before minus after the procedure) was used to categorize the patients. Patients with a ΔVCSS of ≤0 were defined as having LCI after VA, and patients with ≥1 point decrease in the VCSS after VA (ΔVCSS ≥1) as having some benefit from the procedure and, therefore, "clinical improvement." The characteristics of both groups were compared, and multivariable regression analysis was performed to identify factors independently associated with LCI. A second analysis was performed based on the VVSymQ instrument, which measures patient-reported outcomes using five specific symptoms (ie, heaviness, achiness, swelling, throbbing pain, and itching). Patients with LCI showed no improvement in any of the five symptoms, and those with clinical improvement had a decrease in severity of at least one symptom. RESULTS: A total of 3544 patients underwent initial treatment of CVD with a single VA. Of the 3544 patients, 2607 had VCSSs available before and after VA, and 420 (16.1%) had LCI based on the ΔVCSS. Patients with LCI were more likely to be significantly older and African American and have CEAP C2 disease compared with patients with clinical improvement. Patients with clinical improvement were more likely to have reported using compression stockings before treatment. The vein diameters were not different between the two groups. The incidence of complications was overall low, with minor differences between the two groups. However, the patients with LCI were significantly more likely to have symptoms after intervention than those with improvement. Patients with LCI were more likely to have technical failure, defined as vein recanalization. On multivariable regression, age (odds ratio [OR], 1.01; 95% confidence interval [CI], 1.00-1.02) and obesity (OR, 1.47; 95% CI, 1.09-2.00) were independently associated with LCI, as was treatment of less severe disease (CEAP C2; OR, 1.82; 95% CI, 1.30-2.56) compared with more advanced disease (C4). The lack of compression therapy before intervention was also associated with LCI (OR, 6.05; 95% CI, 4.30-8.56). The analysis based on the VVSymQ showed similar results. CONCLUSIONS: LCI after VA is associated with treating patients with a lower CEAP class (C2 vs C4) and a lack of compression therapy before intervention. Importantly, no significant association between vein size and clinical improvement was observed.

A comparison of below-knee vs above-knee endovenous ablation of varicose veins.

OBJECTIVE: Varicose veins have a significant impact on quality of life and can commonly occur in the thigh and calves. However, there has been no large-scale investigation examining the relationship between anatomic distribution and outcomes after varicose vein treatment. This study sought to compare below-the-knee (BTK) and above-the-knee (ATK) varicose vein treatment outcomes. METHODS: Employing the Vascular Quality Initiative Varicose Vein Registry, 13,731 patients undergoing varicose vein ablation for either BTK or ATK lesions were identified. Outcomes were assessed using patient-reported outcomes (PROs) and the Venous Clinical Severity Score (VCSS). Continuous variables were compared using the t-test, and categorical variables were analyzed using the χ2 test. Multivariable logistic regression was used to estimate the odds of improvement after intervention. The multivariable model controlled for age, gender, race, preoperative VCSS composite score, and history of deep vein thrombosis. RESULTS: Patients who received below-knee treatment had a lower preoperative VCSS composite (7.0 ± 3.3 vs 7.7 ± 3.3; P < .001) and lower PROs composite scores (11.1 ± 6.4 vs 13.0 ± 6.6; P < .001) compared with those of patients receiving above-knee treatment. However, on follow-up, patients receiving below-knee intervention had a higher postoperative VCSS composite score (4.4 ± 3.3 vs 3.9 ± 3.5; P < .001) and PROs composite score (6.1 ± 4.4 vs 5.8 ± 4.5; P = .007), the latter approaching statistical significance. Patients receiving above-knee interventions also demonstrated more improvement in both composite VCSS (3.8 ± 4.0 vs 2.9 ± 3.7; P < .001) and PROs (7.1 ± 6.8 vs 4.8 ± 6.6; P < .001). Multivariable logistic regression analysis similarly revealed that patients receiving above-knee treatment had significantly higher odds of improvement in VCSS composite in both the unadjusted (odds ratio [OR], 1.45; 95% confidence interval [CI], 1.28-1.65; P < .001 and adjusted (OR, 1.31; 95% CI, 1.14-1.50; P < .001) models. Patients receiving above-knee treatment also had a significantly higher odds of reporting improvement in PROs composite in both the unadjusted (OR, 1.85; 95% CI, 1.64-2.11; P < .001) and adjusted (OR, 1.65; 95% CI, 1.45-1.88; P < .001) models. CONCLUSIONS: Treatment region has a significant association with PROs and VCSS composite scores after varicose vein interventions. Preoperatively, there were significant differences in the composite scores of VCSS and PROs with patients receiving BTK treatment exhibiting less severe symptoms. Yet, the association appeared to reverse postoperatively, with those receiving BTK treatments exhibiting worse PROs, worse VCSS composites scores, and less improvement in VCSS composite scores. Therefore, BTK interventions pose a unique challenge compared with ATK interventions in ensuring commensurate clinical improvement after treatment.

Transcriptomic Profiling Identifies Ferroptosis-Related Gene Signatures in Ischemic Muscle Satellite Cells Affected by Peripheral Artery Disease-Brief Report.

BACKGROUND: We hypothesized that transcriptomic profiling of muscle satellite cells in peripheral artery disease (PAD) would identify damage-related pathways contributing to skeletal muscle myopathy. We identified a potential role for ferroptosis-a form of programmed lytic cell death by iron-mediated lipid peroxidation-as one such pathway. Ferroptosis promotes myopathy in ischemic cardiac muscle but has an unknown role in PAD. METHODS: Muscle satellite cells from donors with PAD were obtained during surgery. cDNA libraries were processed for single-cell RNA sequencing using the 10X Genomics platform. Protein expression was confirmed based on pathways inferred by transcriptomic analysis. RESULTS: Unsupervised cluster analysis of over 25 000 cells aggregated from 8 donor samples yielded distinct cell populations grouped by a shared unique transcriptional fingerprint. Quiescent cells were diminished in ischemic muscle while myofibroblasts and apoptotic cells were prominent. Differential gene expression demonstrated a surprising increase in genes associated with iron transport and oxidative stress and a decrease in GPX4 (glutathione peroxidase 4) in ischemic PAD-derived cells. Release of the danger signal HMGB1 (high mobility group box-1) correlated with ferroptotic markers including surface transferrin receptor and were higher in ischemia. Furthermore, lipid peroxidation in muscle satellite cells was modulated by ferrostatin, a ferroptosis inhibitor. Histology confirmed iron deposition and lipofuscin, an inducer of ferroptosis in PAD-affected muscle. CONCLUSIONS: This report presents a novel finding that genes known to be involved in ferroptosis are differentially expressed in human skeletal muscle affected by PAD. Targeting ferroptosis may be a novel therapeutic strategy to reduce PAD myopathy.

COVID-associated acute limb ischemia during the Delta surge and the effect of vaccines.

OBJECTIVE: Hypercoagulability is common in severe acute respiratory syndrome coronavirus 2 and has been associated with arterial thrombosis leading to acute limb ischemia (ALI). Our objective was to determine the outcomes of concurrent coronavirus disease 2019 (COVID-19) infection and ALI, particularly during the Delta variant surge and the impact of vaccination status. METHODS: A retrospective review was performed of patients treated at a single health care system between March 2020 and December 2021 for ALI and recent (<14 days) COVID-19 infection or who developed ALI during hospitalization for the same disease. Patients were grouped by year as well as by pre and post Delta variant emergence in 2021 based on the World Health Organization timeline (January to May vs June to December). Baseline demographics, imaging, interventions, and outcomes were evaluated. A control cohort of all patients with ALI requiring surgical intervention for a 2-year period prior to the pandemic was used for comparison. Primary outcomes were in-hospital mortality and amputation-free survival. Kaplan-Meier survival and Cox proportional hazards analysis were performed. RESULTS: Forty acutely ischemic limbs were identified in 36 patients with COVID-19, the majority during the Delta surge (52.8%) and after the wide availability of vaccines. The rate of COVID-19-associated ALI, although low overall, nearly doubled during the Delta surge (0.37% vs 0.20%; P = .09). Intervention (open or endovascular revascularization vs primary amputation) was performed on 31 limbs in 28 individuals, with the remaining eight treated with systemic anti-coagulation. Postoperative mortality was 48%, and overall mortality was 50%. Major amputation following revascularization was significantly higher with COVID-19 ALI (25% vs 3%; P = .006) compared with the pre-pandemic group. Thirty-day amputation-free survival was significantly lower (log-rank P < .001). COVID-19 infection (adjusted hazard ratio, 6.2; P < .001) and age (hazard ratio, 1.1; P = .006) were associated with 30-day amputation in multivariate analysis. Severity of COVID-19 infection, defined as vasopressor usage, was not associated with post-revascularization amputation. There was a higher incidence of re-thrombosis in the latter half of 2021 with the Delta surge, as reintervention for recurrent ischemia of the same limb was more common than our previous experience (21% vs 0%; P = .55). COVID-19-associated limb ischemia occurred almost exclusively in non-vaccinated patients (92%). CONCLUSIONS: ALI observed with Delta appears more resistant to standard therapy. Unvaccinated status correlated highly with ALI occurrence in the setting of COVID-19 infection. Information of limb loss as a COVID-19 complication among non-vaccinated patients may help to increase compliance.

Attenuated cell-cycle division protein 2 and elevated mitotic roles of polo-like kinase 1 characterize deficient myoblast fusion in peripheral arterial disease.

INTRODUCTION: We propose that MuSC-derived myoblasts in PAD have transcriptomic differences that can highlight underlying causes of ischemia-induced myopathy. METHODS: Differentiation capacity among perfused and ischemic human myoblasts was compared. Following next generation sequencing of mRNA, Ingenuity Pathway Analysis (IPA) was performed for canonical pathway enrichment. Live cell imaging and immunofluorescence were performed to determine myocyte fusion index and protein expression based on insights from IPA, specifically concerning cell cycle regulators including cell-division cycle protein 2 (CDC2) and polo-like kinase 1 (PLK1). RESULTS: Ischemic myoblasts formed attenuated myotubes indicative of reduced fusion. Additionally, myoblasts from ischemic segments showed significant differences in canonical pathways associated with PLK1 (upregulated) and G2/M DNA damage checkpoint regulation (downregulated). PLK1 inhibition with BI2536 did not affect cell viability in any group over 24 h but deterred fusion more significantly in PAD myoblasts. Furthermore, PLK1 inhibition reduced the expression of checkpoint protein CDC2 in perfused but not ischemic cells. CONCLUSION: Differentiating myoblasts derived from ischemic muscle have significant differences in gene expression including those essential to DNA-damage checkpoint regulation and cell cycle progress. DNA-damage checkpoint dysregulation may contribute to myopathy in PAD.

Inflammatory Caspase Activity Mediates HMGB1 Release and Differentiation in Myoblasts Affected by Peripheral Arterial Disease.

Introduction: We previously showed that caspase-1 and -11, which are activated by inflammasomes, mediate recovery from muscle ischemia in mice. We hypothesized that similar to murine models, inflammatory caspases modulate myogenicity and inflammation in ischemic muscle disease. Methods: Caspase activity was measured in ischemic and perfused human myoblasts in response to the NLRP3 and AIM2 inflammasome agonists (nigericin and poly(dA:dT), respectively) with and without specific caspase-1 or pan-caspase inhibition. mRNA levels of myogenic markers and caspase-1 were assessed, and protein levels of caspases-1, -4, -5, and -3 were measured by Western blot. Results: When compared to perfused cells, ischemic myoblasts demonstrated attenuated MyoD and myogenin and elevated caspase-1 mRNA. Ischemic myoblasts also had significantly higher enzymatic caspase activity with poly(dA:dT) (p < 0.001), but not nigericin stimulation. Inhibition of caspase activity including caspase-4/-5, but not caspase-1, blocked activation effects of poly(dA:dT). Ischemic myoblasts had elevated cleaved caspase-5. Inhibition of caspase activity deterred differentiation in ischemic but not perfused myoblasts and reduced the release of HMGB1 from both groups. Conclusion: Inflammatory caspases can be activated in ischemic myoblasts by AIM2 and influence ischemic myoblast differentiation and release of pro-angiogenic HMGB1. AIM2 inflammasome involvement suggests a role as a DNA damage sensor, and our data suggest that caspase-5 rather than caspase-1 may mediate the downstream mediator of this pathway.

Three cases of acute venous thromboembolism in females after vaccination for coronavirus disease 2019.

Since December 2020, four vaccines for SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) have been developed, and three have been approved for immediate use in the United States. Two are mRNA vaccines, and one uses a viral vector mechanism. Thrombotic complications have been reported after vaccine administration, which were primarily cerebral sinus thromboses after administration of the viral vector vaccines. To the best of our knowledge, we are the first to report venous thrombotic complications within days of administration of the mRNA-1273 (Moderna) vaccine. We present a series of three women who developed venous thromboembolism after RNA-1273 vaccination at a single healthcare system.

Health care disparities during the COVID-19 pandemic.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2, is a pandemic with more than 32 million cases and more than 500,000 deaths nationwide. With the significant health consequences seen secondary to COVID-19, health care disparities have been further exacerbated. Mechanisms that have been proposed to account for the increased disparity seen during the COVID-19 pandemic are multifactorial. This review of the literature outlines the unique barriers to health and disparities that are associated with vulnerable communities who have been most impacted by the COVID-19 pandemic in the United States.

Letters of recommendation: Nuanced bias or useful affirmation?

Narrative letters of recommendation (NLORs) have become key elements of the application process for residency and fellowship. The potential to inadvertently admit bias into these subjective narratives has become an area of research focus across many disciplines. In the present review, we have highlighted the current data regarding bias in NLORs. We also believe that one of the most effective methods to eliminate bias from written recommendations is to first understand that it exists. Thus, the objective measures that have been taken to identify bias in NLORs are important steps in the right direction. We have presented and reflected on the accrued data on bias in NLORs pertaining to surgical training.

Linguistic Analysis of Letters of Recommendation for Vascular Surgery and Obstetrics and Gynecology Applicants Detects Differences in Attributable Strengths Based on Gender.

OBJECTIVE: We asked whether letters of recommendation (LOR) written for applicants to vascular surgery (VS), a field where men have traditionally predominated, differentially highlight attributes based on applicant gender. For comparison, LOR for applicants to Obstetrics and Gynecology (Ob/Gyn), a surgical field where women are highly represented were evaluated. DESIGN: We performed a cross-sectional review of LORs for students applying to VS or Ob/Gyn at our institution from 2017 to2018. Blinded to the gender of both the applicant and the letter author, investigators assessed word count per letter and used published rubrics to quantify how many words in the following categories: communal ("friendly"), able ("competent"), standout ("exceptional"), and grindstone ("hardworking"). Frequencies were reported as a function of specialty and gender. SETTING: The study was performed at the University of Pittsburgh Medical Center and included letters written for applicants only to the stated residency programs at University of Pittsburgh Medical Center. PARTICIPANTS: LOR written for self-identified women and men applying to both residencies from US-based allopathic medical schools were de-identified and evaluated by blinded reviewers. RESULTS: One hundred and ninety-eight letters were reviewed for vascular surgery applicants. Two hundred letters were randomly selected from applications to Ob/Gyn as a comparison. Fifty-four vascular (27.8% women) and 63 Ob/Gyn (77.8% women) applicants were reviewed (p < 0.001 for gender). Licensing exam scores were higher for women than men applying to Ob/Gyn. Honor status was similar across fields and gender. Letters were shorter for VS applicants (p = 0.04). Gender-specific words (i.e., "lady" or "gentleman") were used more in VS letters (0.24 ± 0.50 vs 0.14 ± 0.42, p = 0.048). Ability words were more common (4.7 ± 2.6 vs 3.8 ± 2.1, p = 0.028) and grindstone adjectives were less common (3.4 ± 2.3 vs 4.5 ± 3.1, p = 0.024) in letters written for women compared to men VS applicants. Twenty-nine letters written for students applying to VS had honors status. While none written for women mentioned this achievement, 43% of those written for men did (p < 0.05). Letters for women applicants to Ob/Gyn contained more standout adjectives than those written for men (2.12 ± 2.2 vs 1.39 ± 1.25, p = 0.021). CONCLUSIONS: Reference letters for both specialties highlighted attributes differently depending on the gender of the applicant. Although this likely represents an unconscious process, care should be taken to limit potential biases in LOR which are "gatekeepers" to access and advancement.

Elastic Laminar Reorganization Occurs with Outward Diameter Expansion during Collateral Artery Growth and Requires Lysyl Oxidase for Stabilization.

When a large artery becomes occluded, hemodynamic changes stimulate remodeling of arterial networks to form collateral arteries in a process termed arteriogenesis. However, the structural changes necessary for collateral remodeling have not been defined. We hypothesize that deconstruction of the extracellular matrix is essential to remodel smaller arteries into effective collaterals. Using multiphoton microscopy, we analyzed collagen and elastin structure in maturing collateral arteries isolated from ischemic rat hindlimbs. Collateral arteries harvested at different timepoints showed progressive diameter expansion associated with striking rearrangement of internal elastic lamina (IEL) into a loose fibrous mesh, a pattern persisting at 8 weeks. Despite a 2.5-fold increase in luminal diameter, total elastin content remained unchanged in collaterals compared with control arteries. Among the collateral midzones, baseline elastic fiber content was low. Outward remodeling of these vessels with a 10-20 fold diameter increase was associated with fractures of the elastic fibers and evidence of increased wall tension, as demonstrated by the straightening of the adventitial collagen. Inhibition of lysyl oxidase (LOX) function with ß-aminopropionitrile resulted in severe fragmentation or complete loss of continuity of the IEL in developing collaterals. Collateral artery development is associated with permanent redistribution of existing elastic fibers to accommodate diameter growth. We found no evidence of new elastic fiber formation. Stabilization of the arterial wall during outward remodeling is necessary and dependent on LOX activity.

Inflammatory signals and network connections implicate cell-mediated immunity in chronic venous insufficiency.

BACKGROUND: The role of inflammation in superficial venous reflux in varicose veins (VVs) is unknown. Computational network modeling has deduced inflammation in experimental and clinical settings. We measured immune mediators in plasma from competent and incompetent leg veins inferring the role of cellular immunity based on cytokine networks. METHODS: Temperature was assessed using infrared thermography (IRT) to measure inflammation. Blood was obtained during sclerotherapy or endovenous thermal ablation for VVs. Control subjects underwent phlebotomy from saphenous and forearm veins. Vein segments were harvested during surgery. Demographics, clinical, etiology, anatomy and pathophysiology classification, venous clinical severity scores (VCSSs), and body mass index (BMI) were collected. Twenty-five mediators were measured in serum and vein segments. Means were compared using Mann-Whitney U test. Pearson correlations equaling or exceeding a threshold prompted connections among nodes, and mapped as networks. Spearman correlations were performed between interleukin (IL)-17A and both granulocyte macrophage colony stimulation factor, and IL-10 as indicators of pathogenic and nonpathogenic Th17 cell involvement. RESULTS: Age, BMI, and VCSSs differed significantly between groups. Temperatures were higher over diseased veins. Plasma concentrations of 20 cytokines differed between control and patient subjects (P<0.05), and most were lower in patients. C-X-C motif chemokine ligand-9 (aka monokine-induced by gamma interferon), C-X-C motif chemokine ligand 10 (aka IFNγ induced protein 10), and soluble IL-2 receptor-alpha were higher in patients, but not connected to other mediators in networks. In contrast, IL-17A, IL-12p70, and interferon gamma were the only mediators that were more highly interconnected in venous insufficiency. IL-17A and granulocyte macrophage colony stimulating factor (GM-CSF) were highly correlated in chronic venous insufficiency (CVI) but not in controls. In tissue, refluxing VVs significantly higher IL-15 expression than competent saphenous veins. CONCLUSIONS: Venous insufficiency associates with age, BMI, skin temperature, and plasma cytokines associated with interferon gamma and possibly IL-17A signaling. The vein wall may be a source of activation of cellular activation, given elevated IL-15 expression. Correlations between IL-17A and GM-CSF suggested a potential role for pathogenic Th17 cells in VVs. Differentially expressed inflammatory networks induced by venous hypertension may reflect or drive venous damage and ulceration.

Fibrosis Distinguishes Critical Limb Ischemia Patients from Claudicants in a Transcriptomic and Histologic Analysis.

Most patients with critical limb ischemia (CLI) from peripheral arterial disease (PAD) do not have antecedent intermittent claudication (IC). We hypothesized that transcriptomic analysis would identify CLI-specific pathways, particularly in regards to fibrosis. Derivation cohort data from muscle biopsies in PAD and non-PAD (controls) was obtained from the Gene Expression Omnibus (GSE120642). Transcriptomic analysis indicated CLI patients (N = 16) had a unique gene expression profile, when compared with non-PAD controls (N = 15) and IC (N = 20). Ninety-eight genes differed between controls and IC, 2489 genes differed between CLI and controls, and 2783 genes differed between CLI and IC patients. Pathway enrichment analysis showed that pathways associated with TGFß, collagen deposition, and VEGF signaling were enriched in CLI but not IC. Receiver operating curve (ROC) analysis of nine fibrosis core gene expression revealed the areas under the ROC (AUC) were all >0.75 for CLI. Furthermore, the fibrosis area (AUC = 0.81) and % fibrosis (AUC = 0.87) in validation cohort validated the fibrosis discrimination CLI from IC and control (all n = 12). In conclusion, transcriptomic analysis identified fibrosis pathways, including those involving TGFß, as a novel gene expression feature for CLI but not IC. Fibrosis is an important characteristic of CLI, which we confirmed histologically, and may be a target for novel therapies in PAD.

Caspase1/11 signaling affects muscle regeneration and recovery following ischemia, and can be modulated by chloroquine.

BACKGROUND: We previously showed that the autophagy inhibitor chloroquine (CQ) increases inflammatory cleaved caspase-1 activity in myocytes, and that caspase-1/11 is protective in sterile liver injury. However, the role of caspase-1/11 in the recovery of muscle from ischemia caused by peripheral arterial disease is unknown. We hypothesized that caspase-1/11 mediates recovery in muscle via effects on autophagy and this is modulated by CQ. METHODS: C57Bl/6 J (WT) and caspase-1/11 double-knockout (KO) mice underwent femoral artery ligation (a model of hind-limb ischemia) with or without CQ (50 mg/kg IP every 2nd day). CQ effects on autophagosome formation, microtubule associated protein 1A/1B-light chain 3 (LC3), and caspase-1 expression was measured using electron microscopy and immunofluorescence. Laser Doppler perfusion imaging documented perfusion every 7 days. After 21 days, in situ physiologic testing in tibialis anterior muscle assessed peak force contraction, and myocyte size and fibrosis was also measured. Muscle satellite cell (MuSC) oxygen consumption rate (OCR) and extracellular acidification rate was measured. Caspase-1 and glycolytic enzyme expression was detected by Western blot. RESULTS: CQ increased autophagosomes, LC3 consolidation, total caspase-1 expression and cleaved caspase-1 in muscle. Perfusion, fibrosis, myofiber regeneration, muscle contraction, MuSC fusion, OCR, ECAR and glycolytic enzyme expression was variably affected by CQ depending on presence of caspase-1/11. CQ decreased perfusion recovery, fibrosis and myofiber size in WT but not caspase-1/11KO mice. CQ diminished peak force in whole muscle, and myocyte fusion in MuSC and these effects were exacerbated in caspase-1/11KO mice. CQ reductions in maximal respiration and ATP production were reduced in caspase-1/11KO mice. Caspase-1/11KO MuSC had significant increases in protein kinase isoforms and aldolase with decreased ECAR. CONCLUSION: Caspase-1/11 signaling affects the response to ischemia in muscle and effects are variably modulated by CQ. This may be critically important for disease treated with CQ and its derivatives, including novel viral diseases (e.g. COVID-19) that are expected to affect patients with comorbidities like cardiovascular disease.

Low serum vitamin C correlates with an increased risk of peripheral arterial disease in current smokers: Results from NHANES 2003-2004.

BACKGROUND: Cigarette smoking is one of the most critical risk factors for peripheral arterial disease (PAD) and inversely correlated Vitamin C. Here we determine whether serum vitamin C correlates with the risk of PAD, especially among current smokers. METHODS: A cross-sectional analysis of 2383 individuals ≥40 y was performed from the U.S. National Health and Nutrition Examination Survey (NHANES 2003-2004), including measurement of ankle-brachial index (ABI), smoking status and serum vitamin C. We examined the interactions between plasma vitamin C and exposure to smoking on the risk of PAD. RESULTS: 912 (38.2%) were current smokers while 207 participants were diagnosed with PAD based on ABI(ABI≤0.9). Current smokers in the lowest vitamin C quartile had the highest prevalence of PAD (14.1%) compared to other quartiles. However, this trend was not significant in nonsmokers. Current smokers in the lowest quartile had a 2.32-fold risk (95% CI, 1.03-5.32; P = 0.04) for PAD after weighted adjustment for potential confounders, including vitamin D and C-reactive protein. In contrast, non-smokers did not have a differing risk of PAD as a function of vitamin C (P for interaction = 0.019). CONCLUSIONS: As an anti-oxidant and anti-inflammatory, low serum vitamin C appears to associates with the risk of PAD in smokers. A relationship between PAD and vitamin C in non-current smokers is not apparent. Modulating vitamin C in current smokers may help mitigate the risk of PAD and should be a target of mechanistic study.

The VE-PTP Inhibitor AKB-9778 Improves Antitumor Activity and Diminishes the Toxicity of Interleukin 2 (IL-2) Administration.

Administration of interleukin (IL)-2 has led to a durable response in patients with advanced renal cancer and melanoma but is restricted for clinical application because of adverse effects, including the vascular leak syndrome (VLS). VLS is associated with increased circulating levels of the Tie2 antagonist ligand, angiopoietin 2, and decreased Tie2 receptor phosphorylation and downstream signaling in endothelial cells (ECs). Given that vascular endothelial protein tyrosine phosphatase (VE-PTP) is a specific membrane phosphatase in ECs that dephosphorylates Tie2, the effects of targeting VE-PTP by a selective inhibitor AKB-9778 (AKB) in terms of VLS and antitumor efficacy were examined in this study. The authors found, by targeting VE-PTP, that the antitumor effects induced by IL-2 were augmented [tumor-free 44% (IL-2 alone) vs. 87.5% (IL-2+AKB)], associated with enhanced immune cell infiltrate (90% increase for CD8 T cells and natural killer cells). In addition, the side effects of IL-2 therapy were lessened, as demonstrated by diminished lung weight (less vascular leakage) as well as reduced cytokine levels (serum HMGB1 from 137.04±2.69 to 43.86±3.65 pg/mL; interferon-γ from 590.52±90.52 to 31.37±1.14 pg/mL). The authors further sought to determine the potential mechanism of the action of AKB-9778. The findings suggest that AKB-9778 may function through reducing serum angiopoietin 2 level and regulating EC viability. These findings provide insights into the targeting VE-PTP to improve tolerance and efficacy of IL-2 therapy and highlight the clinical potential of AKB-9778 for treating patients with VLS and cancer.

Standardized care protocol and modifications to electronic medical records to facilitate venous ulcer healing.

BACKGROUND: Venous ulcers are painful, recurrent, and difficult to heal. Electronic medical records (EMRs) are often not optimized to track wounds. Specialized wound care programs may not interface with office-based records, creating a need to standardize the process of venous ulcer measurement and dressing documentation within existing systems. This work describes the creation of an EMR protocol to track venous ulcer size, to standardize dressings, to address related health issues, and to improve education of the patient. We hypothesized that the institution of an EMR protocol to track clinical features of venous ulcer patients, including wound size and health status, would facilitate wound healing. METHODS: We performed a retrospective review of a prospective database from September 2014 to May 2017. Modifications to the EMR included the formation of a venous ulcer patient list, a dressing tracker, calculation of total ulcer area, graphing of ulcer size over time, and images of the wound area. Patient education materials were created through the EMR and loaded into an automatic end-visit printout that emphasized smoking cessation, weight loss, and consultation with specialty services as necessary. Quarterly meetings with the supervising physician were established to review each patient's wound progress and to target areas of improvement. RESULTS: During the study period, 204 patients with chronic C5 and C6 disease were observed. Before the start of the project, the healing rate was 53.3%. Wound healing rates improved from 59.5% (quarter 1) to 77.94% (quarter 8). In the quarter before the project started, there were no patients who had quit or cut down on smoking or smokeless tobacco, no patients who were referred for weight loss consultation, and nine who were already patients of bariatric surgery. During the study period, 29% of patients quit smoking, 19% decreased smoking, and 20% cut down smokeless tobacco use. There were 54 patients who underwent advanced arterial evaluation; 175 patients underwent sclerotherapy and 137 patients had endovenous thermal ablation to treat axial reflux in the affected limb. The EMR modification project took 13 months to craft and to implement, with approximately 8 hours of meeting time from the surgical team. CONCLUSIONS: A comprehensive care model for venous ulcer patients through EMR modification improved overall patient care, increased communication between providers, and facilitated ulcer healing. EMR modification can be introduced with an acceptable time investment on the part of both the provider and the institutional information technology team.

TLR4-dependent upregulation of the platelet NLRP3 inflammasome promotes platelet aggregation in a murine model of hindlimb ischemia.

Platelets play a critical role in the pathophysiology of peripheral arterial disease (PAD). The mechanisms by which muscle ischemia regulates aggregation of platelets are poorly understood. We have recently identified the Nod-like receptor nucleotide-binding domain leucine rich repeat containing protein 3 (NLRP3) expressed by platelets as a critical regulator of platelet activation and aggregation, which may be triggered by activation of toll-like receptor 4 (TLR4). In this study, we performed femoral artery ligation (FAL) in transgenic mice with platelet-specific ablation of TLR4 (TLR4 PF4) and in NLRP3 knockout (NLRP3-/-) mice. NLRP3 inflammasome activity of circulating platelets, as monitored by activation of caspase-1 and cleavage of interleukin-1ß (IL-1ß), was upregulated in mice subjected to FAL. Genetic ablation of TLR4 in platelets led to decreased platelet caspase 1 activation and platelet aggregation, which was reversed by the NLRP3 activator Nigericin. Two weeks after the induction of FAL, ischemic limb perfusion was increased in TLR4 PF4 and NLRP3-/- mice as compared to control mice. Hence, activation of platelet TLR4/NLRP3 signaling plays a critical role in upregulating platelet aggregation and interfering with perfusion recovery in muscle ischemia and may represent a therapeutic target to improve limb salvage.