Gene delivery to in situ veins: Differential effects of adenovirus and adeno-associated viral vectors

AbstractPurpose: Gene transfer offers the potential to modify vein graft biology at the time of surgical implantation. Efficiency of gene delivery, stability of expression, and host responses are critical parameters for candidate vectors. We compared the effects of intraluminal exposure with adenovirus (AD) and adeno-associated virus (AAV) vectors on transgene expression and monocyte adhesion (MA) in treated vein segments. Methods: Adult New Zealand white rabbits (N = 51) were anesthetized, and the jugular veins were cannulated bilaterally. Veins were gently distended with either vector (2·108 to 1·1010 infective particles/mL) or vehicle (control) for 30 minutes, after which venous flow was restored. AD and AAV vectors encoding for the marker genes β-galactosidase (LacZ) and green fluorescent protein (GFP) were used. Vessels were explanted 2 to 40 days postinfection for analysis of gene expression (X-gal staining, reverse transcriptase-polymerase chain reaction), MA, and immunohistochemistry. Ex vivo adhesion assays used 51Cr-labeled THP-1 cells. Statistical significance was tested by using analysis of variance with a P value less than.05. Results: All animals survived, and all treated veins were patent at sacrifice. Intraluminal exposure to AD at a titer of 1·109 resulted in near complete transduction of the endothelium at 2 days, with no detectable expression by day 14. At an equal titer of infectious particles, transgene expression was markedly less for AAV at 2 to 7 days, but improved at 2 weeks and persisted to 40 days. MA was significantly increased 2 days after AD exposure (2.7-fold vs control, *P <.002); AAV treatment had no discernible effect on MA. Conclusion: AD-mediated gene transfer to vein segments resulted in robust, transient gene expression that disappeared after 2 weeks. In comparison, AAV-mediated gene delivery was less efficient, but resulted in delayed onset, persistent expression beyond 30 days. AD exposure induced an early increase in MA to the vein surface that was not seen with AAV treatment. Current generations of both AD and AAV vectors have significant, albeit different, limitations for vascular gene therapy. (J Vasc Surg 2000;31:1149-59.

Monocyte adhesion to balloon-injured arteries: The influence of endothelial cell seeding

AbstractObjective: Deendothelialization of injuries of the artery disrupts normal vascular homeostasis, affecting both the structural integrity of the blood vessel wall, as well as the interaction of the arterial surface with blood components such as platelets, leukocytes, and circulating proteins. Leukocyte and, in particular, monocyte recruitment to damaged vessels has been implicated in the pathogenesis of intimal hyperplasia. We hypothesize that reendothelialization is an important modulator of monocyte adhesion to healing arterial surfaces. Methods: New Zealand white rabbits (n = 20) were subjected to bilateral iliofemoral artery balloon injury. Cultured, autologous venous endothelial cells (ECs) were immediately seeded onto one vessel, whereas the contralateral artery received medium alone, to accelerate endothelial relining. Vessels were harvested (5-9 days after injury) for analysis of permeability (Evans Blue dye exclusion), endothelial coverage (anti-CD31 immunohistochemistry), monocyte adhesion (ex vivo binding of 51Na2CrO4-labeled monocytic THP-1 cells), and monocyte recruitment (RAM-11 immunohistochemistry). Results: Improved EC coverage was evidenced by positive staining for CD31 in the seeded vessels. Vessel wall permeability was markedly reduced in EC-seeded arteries (29% ± 10% vs 99% ± 0% surface Evans blue staining, P < .005), consistent with restoration of a functional endothelial barrier. EC seeding significantly reduced ex vivo THP-1 binding to vessels explanted at a mean of 8 days after injury (45,170 ± 8939 vs 85,994 ± 16,500 cells/cm2, P < .05). However, RAM-11 staining revealed no significant difference in overall macrophage accumulation between seeded and control vessels 1 week after injury (111 ± 22 vs 95 ± 14 cells/section, P = .36). Conclusions: Immediate seeding of a balloon-injured rabbit artery with cultured ECs results in accelerated restoration of the endothelial lining. At 1 week, barrier function is improved, and the seeded vessel surface is less adhesive to activated monocytes ex vivo, as compared with injured controls. Nonetheless, EC-seeded and nonseeded arteries demonstrate similar total macrophage accumulation over 1 week. These data suggest that after mechanical arterial injury, endothelial coverage may be one important variable influencing leukocyte adhesion. (J Vasc Surg 2001;33:1247-54.

External Fixation of Proximal Tracheal Airway Stents: A Modified Technique

Treatment of subglottic and proximal tracheal stenosis for nonsurgical candidates includes tracheostomy, Montgomery T tubes, and silicone stents. When used in lesions with concomitant malacia, silicone stents have a high incidence of migration. We describe a simple and effective technique of securing endoluminal stents using an Endo Close suturing device (Coviden, Boston, MA) and an external silicone button in 9 consecutive patients. © 2012 The Society of Thoracic Surgeons

National Survey of Burnout and Distress among Cardiothoracic Surgery Trainees

BACKGROUND: Burnout has been linked to poor job satisfaction, increased medical errors, and is prevalent among healthcare professionals. We sought to characterize burnout and distress among US cardiothoracic surgical (CTS) trainees. METHODS: A 19-question survey was sent to CTS trainees in collaboration with the Thoracic Surgery Residents Association. We queried sociodemographic variables, balance/quality of life (QOL), and indicators of depression and regret. We included questions along the emotional exhaustion, depersonalization, and personal accomplishment subscales of the Maslach Burnout Inventory. RESULTS: The survey was sent to 531 CTS trainees across 76 institutions and there were 108 responses (20.3%). Over 50% of respondents expressed dissatisfaction with balance in their professional life and over 40% screened positively for signs of depression. Over 25% (n=28) of respondents would not complete CTS training again, given a choice. More than half met criteria for burnout on emotional exhaustion and depersonalization subscales. CTS residents with children were more likely to express regret towards pursuing CTS training. A greater proportion of women than men reported poor levels of balance/QOL during training as measured by missed health appointments, negative impact on relationships, and self-perception. Similarly, those in the final three years of training were more likely to report poor levels of balance/QOL. CONCLUSIONS: High rates of burnout, regret, and depression are present among US CTS trainees. Efforts to promote trainee well-being and implement interventions that support those at high risk for burnout are warranted, to benefit trainees as well as the patients they serve