Characterization of Vascular Niche in Systemic Sclerosis by Spatial Proteomics

BACKGROUND

Systemic sclerosis (SSc) is a connective tissue disease that can serve as a model to study vascular changes in response to inflammation, autoimmunity, and fibrotic remodeling. Although microvascular changes are the earliest histopathologic manifestation of SSc, the vascular pathophysiology remains poorly understood.

METHODS

We applied spatial proteomic approaches to deconvolute the heterogeneity of vascular cells at the single-cell level in situ and characterize cellular alterations of the vascular niches of patients with SSc. Skin biopsies of patients with SSc and control individuals were analyzed by imaging mass cytometry, yielding a total of 90 755 cells including 2987 endothelial cells and 4096 immune cells.

RESULTS

We identified 7 different subpopulations of blood vascular endothelial cells (VECs), 2 subpopulations of lymphatic endothelial cells, and 3 subpopulations of pericytes. A novel population of CD34+;αSMA+ (α-smooth muscle actin);CD31+ VECs was more common in SSc, whereas endothelial precursor cells were decreased. Co-detection by indexing and tyramide signal amplification confirmed these findings. The microenvironment of CD34+;αSMA+;CD31+ VECs was enriched for immune cells and myofibroblasts, and CD34+;αSMA+;CD31+ VECs expressed markers of endothelial-to-mesenchymal transition. The density of CD34+;αSMA+;CD31+ VECs was associated with clinical progression of fibrosis in SSc.

CONCLUSIONS

Using spatial proteomics, we unraveled the heterogeneity of vascular cells in control individuals and patients with SSc. We identified CD34+;αSMA+;CD31+ VECs as a novel endothelial cell population that is increased in patients with SSc, expresses markers for endothelial-to-mesenchymal transition, and is located in close proximity to immune cells and myofibroblasts. CD34+;αSMA+;CD31+ VEC counts were associated with clinical outcomes of progressive fibrotic remodeling, thus providing a novel cellular correlate for the crosstalk of vasculopathy and fibrosis.

Intraoperative Corticosteroids and Pacemaker Implantation After Transcatheter Aortic Valve Replacement

BACKGROUND

Transcatheter aortic valve replacement (TAVR) has revolutionized the treatment of aortic stenosis. However, conduction disturbances leading to pacemaker implantation remain a common complication, increasing morbidity and mortality in these patients. Hence, measures to lower its incidence should be taken, and corticosteroid therapy could be effective by reducing inflammation caused by direct mechanical trauma to the conduction system.

METHODS

A retrospective cohort study was conducted at the Centro Hospitalar de Vila Nova de Gaia/Espinho, analyzing the medical records of patients with native severe aortic stenosis who underwent transfemoral TAVR in 2022. The Chi-square test was used to compare the rate of pacemaker implantation in patients who received corticosteroids with patients who didn't. The statistical significance was considered for a p-value <0.05.

RESULTS

A total of 341 patients were included in this study. Monitored anesthesia care was the preferred anesthetic technique (99.1%). Sixty-three point three percent (63.3%) of patients received corticosteroids at the beginning of the procedure. Corticosteroid administration did not significantly affect the incidence of permanent pacemaker implantation (p=0.277), vascular complications on the access site (p=0.765), or in-hospital mortality (p=0.909). Male gender, 1st-degree atrioventricular block, and right branch block were the only identified predictors of permanent pacemaker implantation after transfemoral TAVR (p=0.041 <0.001 and <0.001, respectively).

CONCLUSION

Corticosteroid administration at the beginning of TAVR doesn't seem to influence the incidence of permanent pacemaker implantation, which can suggest that other factors play a more important role in the development of conduction disturbances leading to pacemaker implantation.

Dysfunctional APPL1-Mediated Epigenetic Regulation in Diabetic Vascular Injury

BACKGROUND

APN (adiponectin) and APPL1 (adaptor protein, phosphotyrosine interacting with PH domain and leucine zipper 1) are potent vasculoprotective molecules, and their deficiency (eg, hypoadiponectinemia) contributes to diabetic vascular complications. However, the molecular mechanisms that govern their vasculoprotective genes as well as their alteration by diabetes remain unknown.

METHODS

Diabetic medium-cultured rat aortic endothelial cells, mouse aortic endothelial cells from high-fat-diet animals, and diabetic human aortic endothelial cells were used for molecular/cellular investigations. The in vivo concept-prove demonstration was conducted using diabetic vascular injury and diabetic hindlimb ischemia models.

RESULTS

In vivo animal experiments showed that APN replenishment caused APPL1 nuclear translocation, resulting in an interaction with HDAC (histone deacetylase) 2, which inhibited HDAC2 activity and increased H3Kac27 levels. Based on transcriptionome pathway-specific real-time polymerase chain reaction profiling and bioinformatics analysis, Angpt1 (angiopoietin 1), Ocln (occludin), and Cav1 (caveolin 1) were found to be the top 3 vasculoprotective genes suppressed by diabetes and rescued by APN in an APPL1-dependent manner. APN reverses diabetes-induced inhibition of Cav1 interaction with APPL1. APN-induced Cav1 expression was not affected by Angpt1 or Ocln deficiency, whereas APN-induced APPL1 nuclear translocation or upregulation of Angpt1/Ocln expression was abolished in the absence of Cav1 both in vivo and in vitro, suggesting Cav1 is upstream molecule of Angpt1/Ocln in response to APN administration. Chromatin immunoprecipitation-qPCR (quantitative polymerase chain reaction) demonstrated that APN caused significant enrichment of H3K27ac in Angpt1 and Ocln promoter region, an effect blocked by APPL1/Cav1 knockdown or HDAC2 overexpression. The protective effects of APN on the vascular system were attenuated by overexpression of HDAC2 and abolished by knocking out APPL1 or Cav1. The double knockdown of ANGPT1/OCLN blunted APN vascular protection both in vitro and in vivo. Furthermore, in diabetic human endothelial cells, HDAC2 activity is increased, H3 acetylation is decreased, and ANGPT1/OCLN expression is reduced, suggesting that the findings have important translational implications.

CONCLUSIONS

Hypoadiponectinemia and dysregulation of APPL1-mediated epigenetic regulation are novel mechanisms leading to diabetes-induced suppression of vasculoprotective gene expression. Diabetes-induced pathological vascular remodeling may be prevented by interventions promoting APPL1 nuclear translocation and inhibiting HDAC2.

Prognostic factors for femoropopliteal vascular injuries: surgical decisions matter

Background

Lower limbs are frequently involved in vascular trauma, but it is still not clear which factors lead to unfavorable clinical outcomes.

Objectives

To determine the clinical profile of patients with femoropopliteal injuries, the trauma mechanisms, and treatment and identify which factors led to unfavorable outcomes.

Methods

A retrospective study based on the medical records of patients treated from 2017 to 2021. The following data were assessed: sex, age, distance to reach the hospital, trauma mechanism, hypovolemic shock, additional injuries, treatment of vascular injuries, whether fasciotomy was needed, inappropriate intraoperative decisions, and injury severity score. Need for surgical reintervention, amputation, and death were defined as unfavorable outcomes. Univariate, bivariate, and logistic regression analyses were conducted.

Results

The sample comprised 94 patients; 83% were men; mean age was 30.8 years; combined arterial and venous injuries prevailed (57.5%); and superficial femoral vessels were the most affected (61.7%). Penetrating mechanisms prevailed (80.9%). Arterial injuries were most frequently treated with venous graft (59.6%) and venous injuries underwent ligation (81.4%). In 15% of cases, inappropriate surgical decisions were detected; most often use of the ipsilateral great saphenous vein for arterial reconstruction. Unfavorable outcomes occurred in 44.7%: surgical reintervention was necessary in 21.3% and limb amputation in 25.5%, while 9.5% of the patients died.

Conclusions

These injuries mainly involved young men, victims of gunshot wounds. Superficial femoral vessels were the most injured; concomitant non-vascular trauma was frequent, mainly fractures. Inappropriate surgical decisions increased the need for reinterventions by 34 times. Need for fasciotomy, presence of fracture/dislocation, blunt trauma mechanism, and popliteal artery injury increased the risk of amputation.

Brazilian guidelines on diagnosis and management of traumatic vascular injuries

Trauma is a leading cause of death, permanent disability, and health care cost worldwide. The young and economically active are the most affected population. Exsanguination due to noncompressible torso hemorrhage is one of the most frequent causes of early death, posing a significant challenge to trauma and vascular surgeons. The possibility of limb loss due to vascular injuries must also be considered. In recent decades, the approach to vascular injuries has been significantly modified. Angiotomography has become the standard method for diagnosis, endovascular techniques are currently incorporated in treatment, and damage control, such as temporary shunts, is now the preferred approach for the patients sustaining physiological derangement. Despite the importance of this topic, few papers in the Brazilian literature have offered guidelines on vascular trauma. The Brazilian Society of Angiology and Vascular Surgery has developed Projetos Diretrizes (Guideline Projects), which includes this publication on vascular trauma. Since treating trauma patients is a multidisciplinary effort, the Brazilian Trauma Society (SBAIT) was invited to participate in this project. Members of both societies reviewed the literature on vascular trauma management and together wrote these guidelines on vascular injuries of neck, thorax, abdomen, and extremities.

Five-year survival after retroperitoneal oncologic resection with and without vascular surgeon intervention

OBJECTIVES

Retroperitoneal tumor resection commonly disturbs major vessels; therefore, surgical teams can recruit vascular surgeons to prevent injuries and improve the prognosis of oncologic patients. The objective of the present study is to establish long-term survival after retroperitoneal tumor resection surgery with an emphasis on the potential impact of preventing or repairing major vessel injuries when tumors are adjacent to the aorta or vena cava.

METHODS

Retrospective case series including all cases of surgical removal of retroperitoneal tumors between 2007 and 2020 in a highly specialized hospital in Mexico City. Long-term survival was defined as 5 years after surgical intervention. Descriptive statistics, group-comparison tests, and regression analysis were performed using Stata 16.

RESULTS

From a total of 70 cases, vascular injury occurred in 30 (42.8%) and the vascular surgeon intervened in 19 (27.1%) of them, 4 (21%) were performed by a vascular surgeon with planned intervention, and in 9 (47.3%) cases the vascular surgeon was called to join the surgery due to emergency. Intraoperative bleeding was 2-fold greater in the group with an emergent participation of vascular surgery in contrast with the planned intervention group (4, 235 mL vs 2, 035 mL, p = 0.04). The regression model revealed a significant association between the intervention of a vascular surgeon and long-term survival (OR 59.3, p = 0.03) after adjusting for sociodemographic and characteristics of oncologic nature.

CONCLUSIONS

Planned intervention of vascular surgeons in retroperitoneal tumor resection may have a positive impact not only in trans-operatory period, but also on long-term survival.

Efficacy of leupeptin in treating ischemia in a rat hind limb model

Prolonged tourniquet use can lead to tissue ischemia and can cause progressive muscle and nerve injuries. Such injuries are accompanied by calpain activation and subsequent Wallerian-like degeneration. Several known inhibitors, including leupeptin, are known to impede the activity of calpain and associated tissue damage. We hypothesize that employment of leupeptin in a rat model of prolonged hind limb ischemia can mitigate muscle and nerve injuries. Sprague-Dawley rats (n = 10) weighing between 300-400 g were employed in this study. Their left hind limbs were subjected to blood flow occlusion for a period of 2-h using a neonatal blood pressure cuff. Five rats were given twice weekly intramuscular leupeptin injections, while the other five received saline. After 2 weeks, the animals were euthanized, their sciatic nerves and gastrocnemius muscles were harvested, fixed, stained, and analyzed using NIH Image J software. The administration of leupeptin resulted in larger gastrocnemius muscle fiber cross-sectional areas for the right (non-tourniquet applied) hindlimb as compared to that treated with the saline (p = 0.0110). However, no statistically significant differences were found between these two groups for the injured left hindlimb (p = 0.1440). With regards to the sciatic nerve cross-sectional areas and sciatic functional index, no differences were detected between the leupeptin and control treated groups for both the healthy and injured hindlimbs. This research provides new insights on how to employ leupeptin to inhibit the degenerative effects of calpain and preserve tissues following ischemia resulting from orthopedic or plastic surgery procedures.

Incidence of brachial plexus injury with concurrent subclavian or axillary vascular injury and its influence on reconstruction

INTRODUCTION

Brachial plexus reconstruction with free functional muscle transfers (FFMT) has become a reliable tool in the armamentarium of brachial plexus surgeon (Potter and Ferris, The Journal of hand surgery, European volume, 2017, 42,693-9). The successful execution of performing FFMT relies on favourable motor nerves for coaptation and appropriate vessels for microvascular anastomoses. Due to shared traumatic aetiology, subclavian and axillary vascular injury (SAVI) can coexist with the brachial plexus palsy and may pose a surgical dilemma with such FFMT execution.

METHOD

We performed a retrospective study of 100 consecutive patients who presented to our hospital with brachial plexus injury over a 10-year period. Patient records were reviewed for concomitant SAVI and subsequent treatment that was required for both vascular (SAVI) and brachial plexus injuries (BPI).

RESULTS

Concomitant BPI and SAVI occurred in 27% of patients. Open injuries predicted significantly higher rates of SAVI as well as complete plexus palsy. Complete plexus palsy was associated at a higher rate in the SAVI group compared to the non-SAVI group.

CONCLUSION

Coexistence of SAVI and BPI is frequent. Complete plexus palsy and SAVI are more common in open injuries in this study. Complete plexus palsy is the most common indication for FFMT in BPI. Surgical execution of FFMT is more challenging in the setting of previous SAVI and requires careful consideration of the microsurgical plan. We recommend that all patients with previous SAVI or potential need for FFMT in this setting undergo vascular imaging at the time of acute injury and prior to any free flap reconstructive procedures.

Damage control in penetrating carotid artery trauma: changing a 100-year paradigm

Carotid artery trauma carries a high risk of neurological sequelae and death. Surgical management of these injuries has been controversial because it entails deciding between repair or ligation of the vessel, for which there is still no true consensus either way. This article proposes a new management strategy for carotid artery injuries based on the principles of damage control surgery which include endovascular and/or traditional open repair techniques. The decision to operate immediately or to perform further imaging studies will depend on the patient's hemodynamic status. If the patient presents with massive bleeding, an expanding neck hematoma or refractory hypovolemic shock, urgent surgical intervention is indicated. An altered mental status upon arrival is a potentially poor prognosis marker and should be taken into account in the therapeutic decision-making. We describe a step-by-step algorithmic approach to these injuries, including open and endovascular techniques. In addition, conservative non-operative management has also been included as a potentially viable strategy in selected patients, which avoids unnecessary surgery in many cases.

CircSOD2: A Novel Regulator for Smooth Muscle Proliferation and Neointima Formation

OBJECTIVE

Vascular smooth muscle cell (SMC) proliferation contributes to neointima formation following vascular injury. Circular RNA-a novel type of noncoding RNA with closed-loop structure-exhibits cell- and tissue-specific expression patterns. However, the role of circular RNA in SMC proliferation and neointima formation is largely unknown. The objective of this study is to investigate the role and mechanism of circSOD2 in SMC proliferation and neointima formation. Approach and Results: Circular RNA profiling of human aortic SMCs revealed that PDGF (platelet-derived growth factor)-BB up- and downregulated numerous circular RNAs. Among them, circSOD2, derived from back-splicing event of SOD2 (superoxide dismutase 2), was significantly enriched. Knockdown of circSOD2 by short hairpin RNA blocked PDGF-BB-induced SMC proliferation. Inversely, circSOD2 ectopic expression promoted SMC proliferation. Mechanistically, circSOD2 acted as a sponge for miR-206, leading to upregulation of NOTCH3 (notch receptor 3) and NOTCH3 signaling, which regulates cyclin D1 and CDK (cyclin-dependent kinase) 4/6. In vivo studies showed that circSOD2 was induced in neointima SMCs in balloon-injured rat carotid arteries. Importantly, knockdown of circSOD2 attenuated injury-induced neointima formation along with decreased neointimal SMC proliferation.

CONCLUSIONS

CircSOD2 is a novel regulator mediating SMC proliferation and neointima formation following vascular injury. Therefore, circSOD2 could be a potential therapeutic target for inhibiting the development of proliferative vascular diseases.

Nonbone Marrow CD34+ Cells Are Crucial for Endothelial Repair of Injured Artery

[Figure: see text].

Damage control for subclavian artery injury

Mortality from penetrating traumas involving the subclavian vessels can be as high as 60% in pre-hospital settings. Operating room mortality is in the range of 5-30%. This paper presents a case in which a strategy for damage control was employed for a patient with an injury to the origin of the left subclavian artery, using subclavian ligation, with no need for any other intervention, and maintaining viability of the left upper limb via collateral circulation. The authors also review surgical approaches and treatment strategies with a focus on damage control in subclavian vessel injuries.

Experimental comparative assay of tensile resistance of greater saphenous vein from ankle and groin

Background

The great saphenous vein is used as patch material in several types of arterial reconstruction, including trauma and carotid and femoral endarterectomy. There have been reports of saphenous patch blowout, particularly of patches constructed with veins harvested from the ankle. There is a need for objective measurement of the resistance of saphenous vein tissues.

Objectives

To measure the tensile strength of the great saphenous vein harvested at the ankle and groin and analyze the correlation between diameter and tissue strength.

Methods

Venous samples were harvested during elective saphenous stripping in patients with symptomatic varicose veins. Only segments without reflux were included. Ten limbs from eight patients were studied, providing 20 samples in total. Venous segments were opened along their longitudinal axis and fitted to electronic traction assay equipment to obtain values for material maximum tension in kilograms-force per square centimeter (kgf/cm²; the maximum force resisted by the segment, divided by its cross-sectional area).

Results

The average maximum tension in the ankle saphenous vein group ranged from 74.02 to 190.10 kgf/cm² and from 13.53 to 69.45 kgf/cm2 in the groin saphenous vein group (p < 0.0001). The Pearson coefficient for the correlation between vein diameter and maximum tension was -0.852 (moderate to strong inverse correlation).

Conclusions

Ankle saphenous vein tissue from female patients operated for varicose veins has significantly higher resistance than saphenous vein tissue from the groin and there is an inverse relation between vein diameter and resistance of tissue from the same population.

Traumatic injury of radial and ulnar artery with perfusion of the hand through the median artery: a case report

Case description:

A young male patient with a complete section of the ulnar and radial arteries preserved the perfusion of the hand through an anatomical variant, the median artery, identified by angiotomography.

Clinical Findings:

A wound in the distal third of the left forearm with present pulses and adequate hand coloration. An angiotomography of the upper left limb showed a median artery originating as a continuation of the anterior interosseous artery and ending in the palm of the hand with an incomplete superficial palmar arch.

Treatment and Outcomes:

Ligation of both radial and ulnar arteries was performed. It was not possible to follow up the patient.

Clinical Relevance:

Forming the superficial and deep palmar arches, the irrigation of hand comes from the ulnar and radial arteries, which can compromise the viability of the limb when injured. The median artery is present in 0.6-21.1% of the population, originates from the anterior interosseous artery (branch of the ulnar), accompanies the median nerve in its path and ends in the palm joining the superficial palmar arch. Diagnostic imaging is a key tool for assessing arterial circulation and characterizing upper limb vascular lesions. Knowledge of the anatomical variations of the arterial supply of the hand, including variability of the superficial palmar arch, is crucial for the safety and success of hand surgeries.

Treatment of asymptomatic blunt cerebrovascular injury (BCVI): a systematic review

Background

The management of asymptomatic blunt cerebrovascular injury (BCVI) with respect to stroke prevention and vessel healing is challenging.

Objectives

The aim of this systematic review was to determine if a specific treatment results in lower stroke rates and/or improved vessel healing in asymptomatic BCVI.

Data sources

An electronic literature search of MEDLINE, EMBASE, Cochrane Library, CINAHL, SCOPUS, Web of Science, and ClinicalTrials.gov performed from inception to March 2020.

Study eligibility criteria

Studies were included if they reported on a comparison of any treatment for BCVI and stroke and/or vessel healing rates.

Participants and interventions

Adult patients diagnosed with asymptomatic BCVI(s) who were treated with any preventive medication or procedure.

Study appraisal and synthesis methods

All studies were systematically reviewed and bias was evaluated by the Newcastle-Ottawa Scale. No meta-analysis was performed secondary to significant heterogeneity across studies in patient population, screening protocols, and treatment selection. The main outcomes were stroke and healing rate.

Results

Of 8781 studies reviewed, 19 reported on treatment effects for asymptomatic BCVI and were included for review. Any choice of medical management was better than no treatment, but no specific differences between choice of medical management and stroke outcomes were found. Vessel healing was rare and the majority of healed vessels were following low-grade injuries.

Limitations

Majority of the included studies were retrospective and at high risk of bias.

Conclusions or implications of key findings

Asymptomatic BCVI should be treated medically using a consistent, local protocol. High-quality studies on the effect of individual antithrombotic agents on stroke rates and vessel healing for asymptomatic BCVI are required.

Venous ligation versus venous repair: does the procedure impact venous thromboembolism risk?

Background

Traumatic lower extremity venous injuries are most commonly managed with either a vein ligation or repair procedure. Venous injuries are associated with an increased risk of developing venous thromboembolisms (VTE), but little is understood with regard to how specific surgical treatments may impact the risk of developing either a deep vein thrombosis (DVT) or a pulmonary embolism (PE). In this study of lower extremity venous injuries, we hypothesized that venous ligation would be associated with an increased risk of DVT but a lower risk of PE when compared with venous repair.

Methods

Patients were identified from the National Trauma Data Bank (2008 to 2014) with at least one iliac, femoral, popliteal, or tibial venous injury and who received either a vein ligation or repair. The patients were then compared based on the type of procedure and the location of the injury to assess the risk of DVT and PE between the groups.

Results

A total of 1214 patients were identified. There was no difference between patients who received a vein ligation versus a repair with respect to age, injury severity score, or initial systolic blood pressure. There was no difference in the odds of developing either a DVT or PE between patients who were treated with vein ligation versus repair. There was also no difference in VTE rates when stratified by the location of the injury.

Conclusions

In individuals with lower extremity venous injuries, there is no difference in the rate of DVT or PE complications when comparing venous repair and ligation procedures. The role of anticoagulation remains to be elucidated following operative treatment.

Level of evidence

Therapeutic/Care Management, Level IV.

Knockout of the NONO Gene Inhibits Neointima Formation in a Mouse Model of Vascular Injury

[Figure: see text].

Patency of arterial repairs from wartime extremity vascular injuries

BACKGROUND

Extremity vascular injury (EVI) causes significant disability in Veterans of the Afghanistan/Iraq conflicts. Advancements in acute trauma care improved survival and decreased amputations. The study of wartime EVI has relied on successful limb salvage as a surrogate for vascular repair. We used imaging studies as a specific measure of arterial repair durability.

METHODS

Service members with EVI were identified using the Department of Defense Trauma Registry and validated by chart abstraction. Inclusion criteria for the arterial patency subgroup included an initial repair attempt with subsequent imaging reports (duplex ultrasound, CT angiography, and angiogram) documenting initial patency.

RESULTS

The cohort of 527 included 140 Veterans with available imaging studies for 143 arterial repairs; median follow-up from injury time to last available imaging study was 19 months (Q1-Q3: 3-58; range: 1-175). Injury mechanism was predominantly explosions (52%) and gunshot wounds (42%). Of the 143 arterial repairs, 81% were vein grafts. Eight repairs were occluded, replaced or included in extremity amputations. One upper extremity and three transtibial late amputations were performed for chronic pain and poor function averaging 27 months (SD: 4; range: 24-32). Kaplan-Meier analysis estimated patency rates of 99%, 97%, 95%, 91% and 91% at 3, 6, 12, 24, and 36 months, respectively, with similar results for upper and lower extremity repairs. Explosive and gunshot wound injury mechanisms had similar patency rates and upper extremity injuries repaired with vein grafts had increased patency.

CONCLUSIONS

Arterial repair mid-term patency in combat-related extremity injuries is excellent based on imaging studies for 143 repairs. Assertive attempts at acute limb salvage and vascular repair are justified with decisions for amputation versus limb salvage based on the overall condition of the patient and degree of concomitant nerve, orthopedic and soft tissue injuries rather than the presence of arterial injuries.

LEVEL OF EVIDENCE

Therapeutic/care management, level IV.

Rib fracture after median sternotomy for thymoma: an unreported complication

A 47-year-old man was admitted to the clinic with histologically diagnosed thymoma of the anterior mediastinum, pT3N0M1a, stage IYA, type B3. He underwent surgery for primary tumor resection through a median sternotomy and left thoracotomy at the 7th intercostal space to remove pleural metastases. On the first postoperative day, massive bleeding occurred, a resternotomy was carried out but failed to save the patient. A fracture of the right first rib, which injured the right vertebral artery, had caused massive bleeding and was diagnosed at autopsy. Surgeons should keep in mind this potentially fatal complication of a median sternotomy.

Undersized Stentgraft Placement for Traumatic Descending Aorta Rupture, and What Is Next?

BACKGROUND Traumatic injury of the thoracic aorta is proving to be not only the most lethal of traumatic injuries, but also the most urgent reason for vascular intervention among all trauma patients. Endovascular aortic repair is used increasingly often to treat traumatic injuries. We report a case of endovascular treatment and its use as a delayed correction (two-stage treatment) for a traumatic aortic isthmus rupture. CASE REPORT A 20-year-old Asian male was admitted to our department after a car accident presenting symptoms of ischemic shock. Among multiple injuries, a traumatic descending aorta rupture was diagnosed. The patient was referred directly to the operating room for a thoracic endovascular aortic repair (TEVAR). The patient's other trauma-related injuries required additional interventions in the following days. Thirty days after the emergent TEVAR operation, the patient required reintervention due to a major type-I endoleak. Computed tomography angiography revealed a failed stentgraft deployment. We removed the mismatched endovascular equipment and deployed an appropriately sized stentgraft during a hybrid procedure, excluding the ruptured aortic wall altogether. CONCLUSIONS Endovascular treatment of both children and small-framed adults remains a challenge for operating teams. First, no dedicated equipment can be found on the market. Second, measuring and fitting endovascular equipment constitutes a sore point in treatment, so in emergency situations, only off-the-shelf tools are accessible. We assert that, in such cases, the primary procedure should be understood as a lifesaving intervention, awaiting a final and long-lasting solution.

A pilot study of next generation sequencing-liquid biopsy on cell-free DNA as a novel non-invasive diagnostic tool for Klippel-Trenaunay syndrome

OBJECTIVES

Somatic mosaicism of PIK3CA gene is currently recognized as the molecular driver of Klippel-Trenaunay syndrome. However, given the limitation of the current technologies, PIK3CA somatic mutations are detected only in a limited proportion of Klippel-Trenaunay syndrome cases and tissue biopsy remains an invasive high risky, sometimes life-threatening, diagnostic procedure. Next generation sequencing liquid biopsy using cell-free DNA has emerged as an innovative non-invasive approach for early detection and monitoring of cancer. This approach, overcoming the space-time profile constraint of tissue biopsies, opens a new scenario also for others diseases caused by somatic mutations.

METHODS

In the present study, we performed a comprehensive analysis of seven patients (four females and three males) with Klippel-Trenaunay syndrome. Blood samples from both peripheral and efferent vein from malformation were collected and cell-free DNA was extracted from plasma. Tissue biopsies from vascular lesions were also collected when available. Cell-free DNA libraries were performed using Oncomine™ Pan-Cancer Cell-Free Assay. Ion Proton for sequencing and Ion Reporter Software for analysis were used (Life Technologies, Carlsbad, CA, USA).

RESULTS

Cell-free circulating DNA analysis revealed pathogenic mutations in PIK3CA gene in all patients. The mutational load was higher in plasma obtained from the efferent vein at lesional site (0.81%) than in the peripheral vein (0.64%) leading to conclude for a causative role of the identified variants. Tissue analysis, available for one amputated patient, confirmed the presence of the mutation at the malformation site at a high molecular frequency (14-25%), confirming its causative role.

CONCLUSIONS

Our data prove for the first time that the cell-free DNA-next generation sequencing-liquid biopsy, which is currently used exclusively in an oncologic setting, is indeed the most effective tool for Klippel-Trenaunay syndrome diagnosis and tailored personalized treatment.

Maintaining vascular trauma proficiency for military non-vascular surgeons

Background

Vascular injuries in combat casualty patients are common and remain an ongoing concern. In civilian trauma centers, vascular surgeons are frequently available to treat vascular injuries. Within the military, vascular surgeons are not available at all locations where specialty expertise may be optimal. This study aims to determine if a visiting surgeon model, where a general surgeon can visit a civilian trauma center, would be practical in maintaining proficiency in vascular surgery.

Methods

All vascular trauma relevant cases done by any surgical service were identified during a 2-year period at Saint Louis University Hospital between October 1, 2016 and September 30, 2018. These included cases performed by trauma/general, thoracic, vascular, and orthopedic surgery. Predictions on the number of call days to experience an operative case were then calculated.

Results

A total of 316 vascular cases were performed during the time period. A surgeon on call for five 24-hour shifts would experience 2.1 urgent vascular cases with 95% certainty. To achieve five cases with 95% certainty, a surgeon would have to be on call for 34 24-hour shifts.

Discussion

A visiting surgeon model would be very difficult to maintain to acquire or maintain proficiency in vascular surgery. High-volume trauma centers, or centers with significant open vascular cases in addition to trauma, may have more reasonable time requirements, but would have to be evaluated using these methods.

Level of evidence

Economic and value-based evaluations, level II.

Proximal Femur Fracture and Vascular Injury in Adults-Case Report

Vascular complications in the surgical treatment of hip fractures are rare. Depending on the arterial injury, severe intraoperative bleeding or a subacute hematoma formation with arterial pseudoaneurysm development can occur. In the literature, the more frequently described complications are large local hematomas after osteosynthesis with sliding hip screws. This report shows a case of delayed arterial injury after proximal femur osteosynthesis.

Endovascular treatment of traumatic subclavian arteriovenous fistula: case report

A 47-year-old male police officer presented at an outpatients consulting room complaining of exertional dyspnea and swelling and pain in the right arm. He had suffered a perforating gunshot wound of the right infraclavicular region 7 months previously. A chest tomography showed considerable dilatation of the subclavian and cervical veins and veins of the right upper limb, with no clear point of arteriovenous communication. His symptoms exacerbated and he was admitted to hospital before the date scheduled for treatment. He underwent endovascular treatment with an 8x100 mm Fluency covered stent that was placed in the right subclavian artery using the through-and-through technique. Control angiography showed that the fistulous defect had been completely sealed. There was significant relief of the symptoms on the first day after the operation. Traumatic lesions of the subclavian artery are rare, but can be associated with high morbidity and mortality rates. Penetrating trauma is the main cause and arteriovenous fistulas should be ruled out when evaluating penetrating injuries in vascular territories.

An attempt to retrieve an embolized ductal closure device leading to iliac artery dissection in an 11-month-old child: A case report

An 11-month-old patient was referred with the diagnosis of Amplatzer duct occluder II embolization to the right common iliac artery during transcatheter patent ductus arteriosus closure procedure, and unsuccessful retrieval. Following extraction of the device through median laparotomy, a graft interposition was compulsorily performed due to right common iliac artery dissection. Transcatheter device occlusion of patent ductus arteriosus with low complication rates has become the preferred treatment modality in children. However, insisting on transcatheter retrieval of an occluder device should be avoided, as the outcomes can be devastating including limb loss, death or need for multiple surgical and/or endovascular procedures in the future.

Injury of the Carotid Artery during Endoscopic Endonasal Surgery: Surveys of Skull Base Surgeons

Objectives  This study aimed to review endoscopic skull base surgeon experience with internal carotid artery (ICA) injuries during endoscopic endonasal surgery (EES) to provide an estimate of the incidence of ICA injury, the associated factors and identify the best training modalities for the management of this complication. Design  Anonymous electronic survey of past participants at a well-established endoscopic skull base surgery course and a global online community of skull base surgeons. Main Outcome Measures  Relative incidence of ICA injuries during EES, associated anatomic and intraoperative factors, and surgeon experience. Results  At least 20% of surgeons in each surveyed population experienced a carotid artery injury. Reported carotid artery injuries were most common during tumor exposure and removal (48%). The parasellar carotid artery was the most commonly injured segment (39%). Carotid artery injuries were more common in high-volume surgeons, but only statistically significant in one of the two populations. Attendance at a skull base course or courses did not change the incidence of carotid artery injury in either surveyed population. In both surveys, respondents preferred live surgeries or active (not computer simulated) training models. Conclusions  ICA injury is underreported and most common when manipulating the parasellar carotid artery for exposure and tumor dissection. Given the high morbidity and mortality associated with these injuries, vascular injury management should be prioritized and taught in a graduated approach by modern endoscopic skull base courses.

The Perforation of the Superior Vena Cava Secondary to the Left Subclavian Dialysis Catheter

INTRODUCTION

The perforation of the superior vena cava during the placement of dialysis catheter and consequent hemothorax is a rare serious complication.

CASE REPORT

Dialysis catheter was placed in the left subclavian vein in a 69-year-old male patient with chronic renal insufficiency who was hospitalized for intracerebral hematoma. During hemodialysis a day after the procedure, the patient was noted having right-sided hemothorax, causing lethargy, dyspnea, hypotension, and bradycardia. Right tube thoracostomy was performed and 1500 cc of hemorrhagic fluid was drained. Under general anesthesia, the right posterolateral thoracotomy was performed and the tip of the dialysis catheter was found in the pleural space, penetrating the anteromedial side of the superior vena cava. The perforation area was repaired by suturing with 3-0 prolene, and the dialysis catheter was removed externally. Postoperative period was uneventful, and tube thoracostomy was terminated on day 4.

CONCLUSION

Establishing the diagnosis early and accurately and performing appropriate surgery would be lifesaving in superior vena cava perforation due to dialysis catheter.

Comparison of a vascular closure device versus the radial approach to reduce access site complications in non-ST-segment elevation acute coronary syndrome patients: The angio-seal versus the radial approach in acute coronary syndrome trial

OBJECTIVES

To compare the radial versus femoral approach using Angio-Seal for the incidence of access site complications among non-ST-segment elevation acute coronary syndrome patients undergoing invasive strategy.

BACKGROUND

Arterial access is a major site of complications after invasive coronary procedures. Vascular closure devices provide more comfort to patients decreasing time to hemostasis and need for bed rest. However, the inconsistency of data proving their safety limits their routine adoption as a strategy to prevent vascular complications.

METHODS

Single-center non-inferiority trial where 240 patients were randomized to radial or femoral access using Angio-Seal. The primary objective was the occurrence of complications at the arterial puncture site until 30 days after the procedure.

RESULTS

There were no baseline clinical differences between groups, except for a greater prevalence of female patients in the radial group (33.3 vs. 20.0%, P = 0.020). Hemostasis was achieved in the entire radial group with the use of TR Band and in 95% of the procedures in the femoral group with Angio-Seal (P = 0.029). Except for a higher incidence of asymptomatic arterial occlusion in the radial group, there were no differences among the other analyzed outcomes. According to the noninferiority test, the use of Angio-Seal was noninferior to the radial approach, considering the margin of 15% (12.5 vs. 13.3%, difference -0.83%, 95% CI -9.31 - 7.65, P for noninferiority <0.001).

CONCLUSIONS

Angio-Seal seems noninferior in the incidence of access site complications at 30 days when compared with the radial approach. © 2016 Wiley Periodicals, Inc.

Revascularization for acute blunt popliteal artery injury

Case

A 45-year-old man was brought to our hospital in pre-shock after falling from a motorcycle. As we diagnosed him with open fracture of the right femur with leg ischemia, we performed revascularization of injured popliteal artery and treated the leg. The pathological findings showed fragmentation and decrease of elastic fibers and fragmentation of collagen fibers, but no inflammatory cells or intimal hyperplasia, and no dissection.

Outcome

Unfortunately, amputation had to be carried out on the 29th postoperative day due to infection and leg dysfunction. The postoperative course was uneventful. The patient could walk with an artificial leg and was discharged approximately 5 months after popliteal artery replacement.

Conclusions

We report a case of revascularization involving a patient with open fracture of the right femur due to acute blunt popliteal artery injury.

Blunt traumatic aortic injury of right aortic arch in a patient with an aberrant left subclavian artery

Right-sided aortic arch (RAA) is a rare congenital developmental variant present in about 0.1 percent of the population. This anatomical anomaly is commonly associated with congenital heart disease and complications from compression of mediastinal structures. However, it is unknown if patients are at a higher risk of blunt thoracic aortic injury (BTAI). We report a case of a 20-year-old man admitted to the hospital after being hit by an automobile. Computed tomographic scan revealed an RAA with an aberrant left subclavian artery originating from a Kommerell's diverticulum. A pseudo-aneurysm was also seen along the aortic arch. A diagnosis of blunt traumatic aortic injury was made. The patient was successfully treated with a 26mm Vascutek hybrid stentgraft using the frozen elephant trunk technique. A literature review of the pathophysiology of BTAI was performed to investigate if patients with right-sided aortic arch are at a higher risk of suffering from BTAI. Results from the review suggest that although theoretically there may be a higher risk of BTAI in RAA patients, the rarity of this condition has prevented large studies to be conducted. Previously reported cases of BTAI in RAA have highlighted the possibility that the aortic isthmus may be anatomically weak and therefore prone to injury. We have explored this possibility by reviewing current literature of the embryological origins of the aortic arch and descending aorta.

Permissive hypotension in traumatic brain injury with blunt aortic injury: How low can we go?

With an ever-increasing incidence of high impact collisions, polytrauma is becoming increasingly common. Patients with traumatic brain injury (TBI) may require urgent surgical intervention along with maintenance of an adequate mean arterial pressure (MAP) to maintain cerebral perfusion. On the other hand, patients who sustain blunt aortic injuries (BAI) have a high mortality rate, many of them succumbing to their injury at the site of trauma. Surgery has been the mainstay of the management strategy for the remaining survivors. However, in recent years, the paradigm has shifted from early operative management to conservative treatment with aggressive blood pressure and heart rate control, serial imaging, and close clinical monitoring. When TBI and BAI coexist in a patient, it becomes crucial to maintain the MAP within a narrow range to prevent secondary insult to the brain as well as to prevent aortic rupture. We present the management of a case of TBI with traumatic aortic pseudoaneurysm, which required stringent monitoring and maintenance of hemodynamics during decompressive craniectomy.

Estrogen effects on vascular inflammation are age dependent: role of estrogen receptors

OBJECTIVE

17β-Estradiol (E2) offers cardiovascular protection in young female animals and postmenopausal women. In contrast, randomized trials of menopausal hormones performed in older women have shown harm or no cardiovascular benefit. We hypothesize that E2 effects on vascular inflammation are age dependent.

APPROACH AND RESULTS

Young (10 weeks) and aged (52 weeks) female C57BL/6 mice were used as source for primary cultures of bone marrow-derived macrophages (BMMs) and vascular smooth muscle cells (VSMCs). E2 pretreatment of cells derived from young mice attenuated C-reactive protein (CRP)-induced expression of inflammatory mediators. In contrast, E2 pretreatment of cells from aged mice did not alter (BMMs) or paradoxically exaggerated (VSMCs) inflammatory mediator response to CRP. Using E2 receptor (ER) knockout mice, we demonstrated that E2 regulates inflammatory response to CRP in BMMs via ERα and in VSMCs via ERβ. BMMs derived from aged (versus young) mice expressed significantly less ERα mRNA and protein. A selective ligand of the novel ER GPR30 reproduced the E2 effects in BMMs and VSMCs. Unlike in young mice, E2 did not reduce neointima formation in ligated carotid arteries of aged CRP transgenic mice.

CONCLUSIONS

E2 attenuates inflammatory response to CRP in BMMs and VSMCs derived from young but not aged mice and reduces neointima formation in injured carotid arteries of young but not aged CRP transgenic mice. ERα expression in BMMs is greatly diminished with aging. These data suggest that vasoprotective effects of E2 are age dependent and may explain the vasotoxic effects of E2 seen in clinical trials of postmenopausal women.

Bim regulates alloimmune-mediated vascular injury through effects on T-cell activation and death

OBJECTIVE

Bim is a proapoptotic Bcl-2 protein known to downregulate immune responses and to also be required for antigen-induced T-cell activation. However, it is not known how the effect of Bim on these offsetting processes determines the outcome of allogeneic immune responses. We have defined the role of Bim in regulating alloantigen-driven T-cell responses in a model of vascular rejection.

APPROACH AND RESULTS

Bim was required for proliferation of CD4 and CD8 T cells, and for interleukin-2 production, in T cells stimulated with alloantigen in vitro. Moreover, a partial reduction in Bim expression was sufficient to attenuate T-cell activation, whereas a complete elimination of Bim was required to prevent CD4 T-cell death in response to cytokine withdrawl. When alloimmune-mediated vascular rejection was examined using an aortic interposition model, there was significantly less intimal thickening in Bim(+/-), but not Bim(-/-), graft recipients. T-cell proliferation in response to allograft arteries was significantly reduced in both Bim(+/-) and Bim(-/-) mice, but cell death was attenuated only in Bim(-/-) animals.

CONCLUSIONS

Bim controls both T-cell activation and death in response to alloantigen stimulation. These processes act cooperatively to determine the outcome of immune responses in allograft arteries.

Right pulmonary hilar pedicle injury secondary to blunt chest trauma in a child

Combined tracheobronchial and thoracic vascular injury in children following blunt trauma to the chest is potentially life-threatening and almost certain to be fatal unless managed promptly. We report one such incident where prompt identification and early aggressive surgical management prevented an almost certain fatal outcome in a 5-year-old girl with complete disruption of the right main bronchus just distal to the carina, and a tear in the right pulmonary artery.

Vascular smooth muscle cell-derived transforming growth factor-β promotes maturation of activated, neointima lesion-like macrophages

OBJECTIVE

To define the contribution of vascular smooth muscle cell (SMC)-derived factors to macrophage phenotypic modulation in the setting of vascular injury.

APPROACH AND RESULTS

By flow cytometry, macrophages (M4) were the predominant myeloid cell type recruited to wire-injured femoral arteries, in mouse, compared with neutrophils or eosinophils. Recruited macrophages from injured vessels exhibited a distinct expression profile relative to circulating mononuclear cells (peripheral blood monocytes; increased: interleukin-6, interleukin-10, interleukin-12b, CC chemokine receptor [CCR]3, CCR7, tumor necrosis factor-α, inducible nitric oxide synthase, arginase 1; decreased: interleukin-12a, matrix metalloproteinase [MMP]9). This phenotype was recapitulated in vitro by maturing rat bone marrow cells in the presence of macrophage-colony stimulating factor and 20% conditioned media from cultured rat SMC (sMϕ) compared with maturation in macrophage-colony stimulating factor alone (M0). Recombinant transforming growth factor (TGF)-β1 recapitulated the effect of SMC conditioned media. Macrophage maturation studies performed in the presence of a pan-TGF-β neutralizing antibody, a TGF-β receptor inhibitor, or conditioned media from TGF-β-depleted SMCs confirmed that the SMC-derived factor responsible for macrophage activation was TGF-β. Finally, the effect of SMC-mediated macrophage activation on SMC biology was assessed. SMCs cocultured with sMϕ exhibited increased rates of proliferation relative to SMCs cultured alone or with M0 macrophages.

CONCLUSIONS

SMC-derived TGF-β modulates the phenotype of maturing macrophages in vitro, recapitulating the phenotype found in vascular lesions in vivo. SMC-modulated macrophages induce SMC activation to a greater extent than control macrophages.

Adiponectin inhibits tumor necrosis factor-α-induced vascular inflammatory response via caveolin-mediated ceramidase recruitment and activation

RATIONALE

Anti-inflammatory and vascular protective actions of adiponectin are well recognized. However, many fundamental questions remain unanswered.

OBJECTIVE

The current study attempted to identify the adiponectin receptor subtype responsible for adiponectin's vascular protective action and investigate the role of ceramidase activation in adiponectin anti-inflammatory signaling.

METHODS AND RESULTS

Adiponectin significantly reduced tumor necrosis factor (TNF)α-induced intercellular adhesion molecule-1 expression and attenuated TNFα-induced oxidative/nitrative stress in human umbilical vein endothelial cells. These anti-inflammatory actions were virtually abolished by adiponectin receptor 1 (AdipoR1-), but not AdipoR2-, knockdown (KD). Treatment with adiponectin significantly increased neutral ceramidase (nCDase) activity (3.7-fold; P<0.01). AdipoR1-KD markedly reduced globular adiponectin-induced nCDase activation, whereas AdipoR2-KD only slightly reduced. More importantly, small interfering RNA-mediated nCDase-KD markedly blocked the effect of adiponectin on TNFα-induced intercellular adhesion molecule-1 expression. AMP-activated protein kinase-KD failed to block adiponectin-induced nCDase activation and modestly inhibited adiponectin anti-inflammatory effect. In contrast, in caveolin-1 KD (Cav1-KD) cells, >87% of adiponectin-induced nCDase activation was lost. Whereas adiponectin treatment failed to inhibit TNFα-induced intercellular adhesion molecule-1 expression, treatment with sphingosine-1-phosphate or SEW (sphingosine-1-phosphate receptor agonist) remained effective in Cav1-KD cells. AdipoR1 and Cav1 colocalized and coprecipitated in human umbilical vein endothelial cells. Adiponectin treatment did not affect this interaction. There is weak basal Cav1/nCDase interaction, which significantly increased after adiponectin treatment. Knockout of AdipoR1 or Cav1 abolished the inhibitory effect of adiponectin on leukocyte rolling and adhesion in vivo.

CONCLUSIONS

These results demonstrate for the first time that adiponectin inhibits TNFα-induced inflammatory response via Cav1-mediated ceramidase recruitment and activation in an AdipoR1-dependent fashion.

Therapeutic reendothelialization by induced pluripotent stem cells after vascular injury--brief report

OBJECTIVE

Endothelial damage is an early requisite step for atherosclerosis after vascular injury. It has been reported that vascular wall cells can develop from induced pluripotent stem (iPS) cell-derived fetal liver kinase-1-positive (Flk-1(+)) cells. Here, we investigated the efficacies of intravenously administered iPS cell-derived Flk-1(+) cells on reendothelialization and neointimal hyperplasia in a mouse model of vascular injury.

APPROACH AND RESULTS

Femoral arteries of KSN nude mice were injured using a steel wire. Mouse iPS cell-derived Flk-1(+) or Flk-1(-) cells were intravenously injected into those mice at 24 hours after vascular injury. Delivery of iPS cell-derived Flk-1(+) cells significantly attenuated neointimal hyperplasia compared with controls. Evans blue staining of the injured vessel revealed that administration of iPS cell-derived Flk-1(+) significantly enhanced reendothelialization compared with the Flk-1(-) cell control group. Recruitment of PKH26-labeled iPS cell-derived Flk-1(+) cells to the site of injury was also detectable. Expression level of CXCR4 in iPS cell-derived Flk-1(+) cells was 7.5-fold higher than that of iPS cell-derived Flk-1(-) cells. Stromal cell-derived factor-1α treatment significantly enhanced adhesion and migration of iPS cell-derived Flk-1(+) cells to the endothelia, but these were not observed in Flk-1(-) cells.

CONCLUSIONS

Intravenously administered iPS cell-derived Flk-1(+) cells are recruited to the site of vascular injury, thereby enhancing reendothelialization followed by suppression of neointimal hyperplasia. Administration of iPS cell-derived Flk-1(+) cells is a potentially useful therapeutic means for vascular dysfunction and prevention of restenosis after angioplasty.

Toll-like receptor 2/6 agonist macrophage-activating lipopeptide-2 promotes reendothelialization and inhibits neointima formation after vascular injury

OBJECTIVE

Reendothelialization after vascular injury (ie, balloon angioplasty or stent implantation) is clinically extremely relevant to promote vascular healing. We here investigated the therapeutic potential of the toll-like receptor 2/6 agonist macrophage-activating lipopeptide (MALP)-2 on reendothelialization and neointima formation in a murine model of vascular injury.

APPROACH AND RESULTS

The left common carotid artery was electrically injured, and reendothelialization was quantified by Evans blue staining after 3 days. A single injection of MALP-2 (1 or 10 µg, IV) after vascular injury accelerated reendothelialization (P<0.001). Proliferation of endothelial cells at the wound margins determined by 5-ethynyl-2'-deoxyuridine incorporation was significantly higher in MALP-2-treated animals (P<0.05). Furthermore, wire injury-induced neointima formation of the left common carotid artery was completely prevented by a single injection of MALP-2 (10 µg, IV). In vitro, MALP-2 induced proliferation (BrdU incorporation) and closure of an artificial wound of endothelial cells (P<0.05) but not of smooth muscle cells. Protein array and ELISA analysis of isolated primary endothelial cells and ex vivo stimulated carotid segments revealed that MALP-2 stimulated the release of multiple growth factors and cytokines predominantly from endothelial cells. MALP-2 induced a strong activation of the mitogen-activated protein kinase cascade in endothelial cells, which was attenuated in smooth muscle cells. Furthermore, MALP-2 significantly enhanced circulating monocytes and hematopoietic progenitor cells.

CONCLUSIONS

The toll-like receptor 2/6 agonist MALP-2 promotes reendothelialization and inhibits neointima formation after experimental vascular injury via enhanced proliferation and migration of endothelial cells. Thus, MALP-2 represents a novel therapeutic option to accelerate reendothelialization after vascular injury.

Carcinoembryonic antigen-related cell adhesion molecule 1 inhibits MMP-9-mediated blood-brain-barrier breakdown in a mouse model for ischemic stroke

RATIONALE

Blood-brain-barrier (BBB) breakdown and cerebral edema result from postischemic inflammation and contribute to mortality and morbidity after ischemic stroke. A functional role for the carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) in the regulation of reperfusion injury has not yet been demonstrated.

OBJECTIVE

We sought to identify and characterize the relevance of CEACAM1-expressing inflammatory cells in BBB breakdown and outcome after ischemic stroke in Ceacam1(-/-) and wild-type mice.

METHODS AND RESULTS

Focal ischemia was induced by temporary occlusion of the middle cerebral artery with a microfilament. Using MRI and Evans blue permeability assays, we observed increased stroke volumes, BBB breakdown and edema formation, reduction of cerebral perfusion, and brain atrophy in Ceacam1(-/-) mice. This translated into poor performance in neurological scoring and high poststroke-associated mortality. Elevated neutrophil influx, hyperproduction, and release of neutrophil-related matrix metalloproteinase-9 in Ceacam1(-/-) mice were confirmed by immune fluorescence, flow cytometry, zymography, and stimulation of neutrophils. Importantly, neutralization of matrix metalloproteinase-9 activity in Ceacam1(-/-) mice was sufficient to alleviate stroke sizes and improve survival to the level of CEACAM1-competent animals. Immune histochemistry of murine and human poststroke autoptic brains congruently identified abundance of CEACAM1(+)matrix metalloproteinase-9(+) neutrophils in the ischemic hemispheres.

CONCLUSIONS

CEACAM1 controls matrix metalloproteinase-9 secretion by neutrophils in postischemic inflammation at the BBB after stroke. We propose CEACAM1 as an important inhibitory regulator of neutrophil-mediated tissue damage and BBB breakdown in focal cerebral ischemia.

Bone marrow-derived Kruppel-like factor 10 controls reendothelialization in response to arterial injury

OBJECTIVE

The objective of this study was to investigate the role of Kruppel-like factor (KLF) 10, a zinc-finger transcription factor, in bone marrow (BM)-derived cell responses to arterial endothelial injury. Accumulating evidence indicates that BM-derived progenitors are recruited to sites of vascular injury and contribute to endothelial repair.

APPROACH AND RESULTS

In response to carotid artery endothelial denudation, KLF10 mRNA expression was markedly increased in both BM and circulating lin(-) progenitor cells. To examine the specific role of KLF10 in arterial reendothelialization, we used 2 models of endothelial denudation (wire- and thermal-induced injury) of the carotid artery in wild-type (WT) and KLF10(-/-) mice. WT mice displayed higher areas of reendothelialization compared with KLF10(-/-) mice after endothelial injury using either method. BM transplant studies revealed that reconstitution of KLF10(-/-) mice with WT BM fully rescued the defect in reendothelialization and increased lin(-)CD34(+)kinase insert domain receptor(+) progenitors in the blood and injured carotid arteries. Conversely, reconstitution of WT mice with KLF10(-/-) BM recapitulated the defects in reendothelialization and peripheral cell progenitors. The media from cultured KLF10(-)/(-) BM progenitors was markedly inefficient in promoting endothelial cell growth and migration compared with the media from WT progenitors, indicative of defective paracrine trophic effects from KLF10(-)/(-) BM progenitors. Finally, BM-derived KLF10(-/-) lin(-) progenitors from reconstituted mice had reduced CXC-chemokine receptor 4 expression and impaired migratory responses.

CONCLUSIONS

Collectively, these observations demonstrate a protective role for BM-derived KLF10 in paracrine and homing responses important for arterial endothelial injury and highlight KLF10 as a possible therapeutic target to promote endothelial repair in vascular disease states.