Histone Methylation Directs Myeloid TLR4 Expression and Regulates Wound Healing following Cutaneous Tissue Injury.

Myeloid cells are critical for orchestrating regulated inflammation during wound healing. TLRs, particularly TLR4, and its downstream-signaling MyD88 pathway play an important role in regulating myeloid-mediated inflammation. Because an initial inflammatory phase is vital for tissue repair, we investigated the role of TLR4-regulated, myeloid-mediated inflammation in wound healing. In a cutaneous tissue injury murine model, we found that TLR4 expression is dynamic in wound myeloid cells during the course of normal wound healing. We identified that changes in myeloid TLR4 during tissue repair correlated with increased expression of the histone methyltransferase, mixed-lineage leukemia 1 (MLL1), which specifically trimethylates the histone 3 lysine 4 (H3K4me3) position of the TLR4 promoter. Furthermore, we used a myeloid-specific Mll1 knockout (Mll1f/fLyz2Cre+ ) to determine MLL1 drives Tlr4 expression during wound healing. To understand the critical role of myeloid-specific TLR4 signaling, we used mice deficient in Tlr4 (Tlr4-/- ), Myd88 (Myd88 -/-), and myeloid-specific Tlr4 (Tlr4f/fLyz2Cre+) to demonstrate delayed wound healing at early time points postinjury. Furthermore, in vivo wound myeloid cells isolated from Tlr4-/- and Myd88 -/- wounds demonstrated decreased inflammatory cytokine production. Importantly, adoptive transfer of monocyte/macrophages from wild-type mice trafficked to wounds with restoration of normal healing and myeloid cell function in Tlr4-deficient mice. These results define a role for myeloid-specific, MyD88-dependent TLR4 signaling in the inflammatory response following cutaneous tissue injury and suggest that MLL1 regulates TLR4 expression in wound myeloid cells.

Effect of Mentoring on Match Rank of Integrated Vascular Surgery Residents.

BACKGROUND: Mentoring relationships have been encouraged for medical students interested in surgical specialties. We investigated the role of mentoring relationships of integrated vascular surgery residents, while in medical school. We hypothesized that mentoring relationships between medical students and vascular surgeons would have a positive effect on match outcome in the integrated vascular surgery residency match. METHODS: We used an online survey that respondents completed on a smartphone, tablet, or computer. This was created with Qualtrics Software. The survey was circulated to all North American Integrated Vascular Surgery residents, with the support of the Association of Program Directors in Vascular Surgery Recruitment Committee and the Society for Vascular Surgery Resident/Student Outreach Committee. Questions were posed either as Likert Scale or as multiple choice. Data were analyzed in Stata. RESULTS: Response rate (67 total responses of 241 polled residents) was 28%. Earlier postgraduate year residents were more likely to have had vascular surgeon mentors (P = 0.033). There was no association between having a mentor and match rank; however, those with vascular surgeon mentors matched higher on their rank list (P = 0.022). 50% of respondents indicated that mentoring was influential in the choice of integrated residency. Respondents with nonvascular surgeon mentors were more likely to answer negatively regarding their mentor's knowledge about other integrated (P < 0.0001) and traditional programs (P < 0.0001) while residents with a vascular surgeon mentor were more likely to respond positively to this question (P < 0.0001). Regarding the effectiveness of mentorship, 81% indicated their mentor was accessible, 92% responded that their mentor demonstrated professional integrity, and 76% responded that their mentor prioritized their success. CONCLUSIONS: Integrated vascular surgery residents were generally positive about their medical school mentors. Our data indicate that surgical mentorship in medical school is effective, both in influencing medical students to choose the vascular surgery specialty and in improving match rank-vascular surgeons were more knowledgeable and mentees with vascular surgeon mentors tended to be more successful in the match.

Alignment of Personality Is Associated With Increased Intraoperative Entrustment.

OBJECTIVE: To determine the association between intraoperative entrustment and personality alignment. SUMMARY BACKGROUND DATA: For surgical residents, achieving operative autonomy has become increasingly difficult. The impact of faculty-resident operative interactions in accomplishing this goal is not well understood. We hypothesized that if operative dyads (faculty and resident) had personality alignment or congruency, then resident entrustment in the operating room would increase. METHODS: We completed a retrospective analysis of 63 operations performed from September 2015 to August 2016. Operations were scored using OpTrust, a validated tool that assesses progressive entrustment of responsibility to surgical residents in the operating room. All dyads were classified as having congruent or incongruent personality alignment as measured by promotion or prevention orientation using the regulatory focus questionnaire. The association between personality congruence and OpTrust scores was identified using multivariable linear regression. RESULTS: A total of 35 congruent dyads and 28 incongruent dyads were identified. Congruent dyads had a higher percentage of "very difficult" cases (33.3 vs. 7.4%, P = 0.017), female residents (37.1 vs. 14.3%, P = 0.042) and faculty with fewer years of experience (10.4 vs. 14.8%, P = 0.028) than incongruent dyads. In addition to post-graduate year level, dyad congruency was independently associated with a 0.88 increase (95% CI [0.27-1.49], P = 0.006) in OpTrust scores (overall range 2-8), after adjusting for case difficulty, faculty experience, and post-graduate year. CONCLUSIONS: Congruent operative dyads are associated with increased operative entrustment as demonstrated by increased OpTrust scores. Developing awareness and strategies for addressing incongruence in personality in the operative dyad is needed.

Murine macrophage chemokine receptor CCR2 plays a crucial role in macrophage recruitment and regulated inflammation in wound healing.

Macrophages play a critical role in the establishment of a regulated inflammatory response following tissue injury. Following injury, CCR2+ monocytes are recruited from peripheral blood to wound tissue, and direct the initiation and resolution of inflammation that is essential for tissue repair. In pathologic states where chronic inflammation prevents healing, macrophages fail to transition to a reparative phenotype. Using a murine model of cutaneous wound healing, we found that CCR2-deficient mice (CCR2-/- ) demonstrate significantly impaired wound healing at all time points postinjury. Flow cytometry analysis of wounds from CCR2-/- and WT mice revealed a significant decrease in inflammatory, Ly6CHi recruited monocyte/macrophages in CCR2-/- wounds. We further show that wound macrophage inflammatory cytokine production is decreased in CCR2-/- wounds. Adoptive transfer of mT/mG monocyte/macrophages into CCR2+/+ and CCR2-/- mice demonstrated that labeled cells on days 2 and 4 traveled to wounds in both CCR2+/+ and CCR2-/- mice. Further, adoptive transfer of monocyte/macrophages from WT mice restored normal healing, likely through a restored inflammatory response in the CCR2-deficient mice. Taken together, these data suggest that CCR2 plays a critical role in the recruitment and inflammatory response following injury, and that wound repair may be therapeutically manipulated through modulation of CCR2.

Macrophage-Mediated Inflammation in Normal and Diabetic Wound Healing.

The healing of cutaneous wounds is dependent on the progression through distinct, yet overlapping phases of wound healing, including hemostasis, inflammation, proliferation, and resolution/remodeling. The failure of these phases to occur in a timely, progressive fashion promotes pathologic wound healing. The macrophage (MΦ) has been demonstrated to play a critical role in the inflammatory phase of tissue repair, where its dynamic plasticity allows this cell to mediate both tissue-destructive and -reparative functions. The ability to understand and control both the initiation and the resolution of inflammation is critical for treating pathologic wound healing. There are now a host of studies demonstrating that metabolic and epigenetic regulation of gene transcription can influence MΦ plasticity in wounds. In this review, we highlight the molecular and epigenetic factors that influence MΦ polarization in both physiologic and pathologic wound healing, with particular attention to diabetic wounds.

Development, Launch, and Evaluation of an Open-Access Vascular Surgery Handbook through House Officer Curriculum Crowdsourcing.

BACKGROUND: Free digital platforms are smartphone-compatible and permit self-directed curriculum development based on learners' interests and educational needs. We developed a free mobile vascular surgery handbook initiated, authored, and edited by surgical house officers and surveyed on the content and users. METHODS: Using a free digital platform, house officers developed a vascular surgery handbook. Initiated by a single user for conference preparation and clinical care, the use expanded through sharing among residents. The handbook was then deployed at a second medical center, with free access granted to users after completing a survey. Handbook and content use were evaluated based on user ratings ≥4 on a Likert scale from 1 to 5, where 1 = "strongly disagree" and 5 = "completely agree." Domains assessed included handbook ease of use, content, and relevance to a variety of learning environments and goals (e.g., preparation for the operating room, rounds, clinic, teaching conferences, and examinations). Analytic methods included qualitative analysis, graphical evaluation, and categorical tests. RESULTS: The handbook is organized into sections, with each consisting of multiple pages and/or posts related to the section topic. Sections with the most content included lower extremity arterial disease, endovascular aneurysm repair/thoracic endovascular aortic repair, venous disease, anticoagulation, and anatomy/exposures. Fifty-four users participated in the evaluation phase, including different types of surgical residents (35%), medical students (30%), and anesthesia residents (22%). Sixty-nine percent of participants were in their position for <2 years. The average age was 29.1 years, and 57% were women. Preferred learning styles among users at the time of enrollment primarily included question banks (52%), followed by slide-based lectures (15%) and "chalk talk" lectures (13%). Of the users who participated in the presurvey, 43 users participated in the postsurvey with a general agreement on the handbook being an easy-to-use resource that was useful for gaining overall knowledge and contained accurate information. Users generally agreed they would recommend the handbook to a colleague. CONCLUSIONS: References customized to user needs can be developed through crowdsourcing and published with free digital resources. These approaches allow mobile access to useful information during conferences and clinical care. House officers' self-perceived educational needs can be targeted for tailored educational initiatives.

The Clinical Impact of Cardiology Consultation Prior to Major Vascular Surgery.

OBJECTIVE: To understand statewide variation in preoperative cardiology consultation prior to major vascular surgery and to determine whether consultation was associated with differences in perioperative myocardial infarction (poMI). SUMMARY BACKGROUND DATA: Medical consultation prior to major vascular surgery is obtained to reduce perioperative risk. Despite perceived benefit of preoperative consultation, evidence is lacking specifically for major vascular surgery on the effect of preoperative cardiac consultation. METHODS: Patient and clinical data were obtained from a statewide vascular surgery registry between January 2012 and December 2014. Patients were risk stratified by revised cardiac risk index category and compared poMI between patients who did or did not receive a preoperative cardiology consultation. We then used logistic regression analysis to compare the rate of poMI across hospitals grouped into quartiles by rate of preoperative cardiology consultation. RESULTS: Our study population comprised 5191 patients undergoing open peripheral arterial bypass (n = 3037), open abdominal aortic aneurysm repair (n = 332), or endovascular aneurysm repair (n = 1822) at 29 hospitals. At the patient level, after risk-stratification by revised cardiac risk index category, there was no association between cardiac consultation and poMI. At the hospital level, preoperative cardiac consultation varied substantially between hospitals (6.9%-87.5%, P <0.001). High preoperative consulting hospitals (rate >66%) had a reduction in poMI (OR, 0.52; confidence interval: 0.28-0.98; P <0.05) compared with all other hospitals. These hospitals also had a statistically greater consultation rate with a variety of medical specialties. CONCLUSIONS: Preoperative cardiology consultation for vascular surgery varies greatly between institutions, and does not appear to impact poMI at the patient level. However, reduction of poMI was noted at the hospitals with the highest rate of preoperative cardiology consultation as well as a variety of medical services, suggesting that other hospital culture effects play a role.

The effects of preoperative cardiology consultation prior to elective abdominal aortic aneurysm repair on patient morbidity.

Objectives The relationship between preoperative medical consultations and postoperative complications has not been extensively studied. Thus, we investigated the impact of preoperative consultation on postoperative morbidity following elective abdominal aortic aneurysm repair. Methods A retrospective review was conducted on 469 patients (mean age 72 years, 20% female) who underwent elective abdominal aortic aneurysm repair from June 2007 to July 2014. Data elements included detailed medical history, preoperative cardiology consultation, and postoperative complications. Primary outcomes included 30-day morbidity, consult-specific morbidity, and mortality. A bivariate probit regression model accounting for the endogeneity of binary preoperative medical consult and patient variability was estimated with a maximum likelihood function. Results Eighty patients had preoperative medical consults (85% cardiology); thus, our analysis focuses on the effect of cardiac-related preoperative consults. Hyperlipidemia, increased aneurysm size, and increased revised cardiac risk index increased likelihood of referral to cardiology preoperatively. Surgery type (endovascular versus open repair) was not significant in development of postoperative complications when controlling for revised cardiac risk index ( p = 0.295). After controlling for patient comorbidities, there was no difference in postoperative cardiac-related complications between patients who did and did not undergo cardiology consultation preoperatively ( p = 0.386). Conclusions When controlling for patient disease severity using revised cardiac risk index risk stratification, preoperative cardiology consultation is not associated with postoperative cardiac morbidity.

The natural history of type II endoleaks after endovascular aneurysm repair for ruptured abdominal aortic aneurysm.

OBJECTIVE: The natural history of type II endoleak (T2EL) after endovascular aneurysm repair (EVAR) for ruptured abdominal aortic aneurysm (rAAA) remains elusive; as such, treatment guidelines are ill defined. The purpose of this study was to better delineate the natural history of T2EL after EVAR for rAAA in an effort to determine the need for reintervention and optimal surveillance. METHODS: A retrospective record review was conducted of all patients undergoing EVAR for rAAA in two large tertiary care academic vascular centers. Patient demographics, comorbidities, anatomic variables, and operative details were analyzed. Primary outcomes included the presence of T2EL, reintervention, delayed rupture, and aneurysm-related death. RESULTS: EVAR was used to treat rAAA in 56 patients between 2000 and 2013. Mean follow-up of this cohort was 634 days. Completion arteriogram demonstrated T2ELs in 12 patients (21%), and an additional four T2ELs (7%) were found by postoperative computed tomography angiogram that were not identified on the completion angiogram. Body mass index was the only statistically significant variable associated with the development of T2EL (P = .03). Preoperative warfarin use, aortic thrombus burden, and device type did not correlate with T2EL development. Iliolumbar vessels supplied 75% (n = 12) of T2ELs. Of the 14 patients with T2ELs who underwent serial imaging postoperatively, six (43%) sealed spontaneously. Five patients (36%) underwent reintervention for T2EL by way of coil embolization-four in which treatment was initiated by attending preference. One patient was treated for ongoing anemia in the immediate postoperative period. There was no sac expansion, delayed rupture, or graft explantation. CONCLUSIONS: T2ELs after EVAR for rAAA are common and appear to be associated with a benign natural history if left untreated. Although many will spontaneously seal early in the postoperative period, those that remain patent do not appear to increase the risk for sac expansion or delayed rupture or affect patient survival. As such, a conservative approach to treatment of T2ELs in rAAA may be warranted.

Greater faculty familiarity with residents improves intraoperative entrustment.

BACKGROUND: Longitudinal contact between faculty and residents facilitates greater faculty entrustment. The purpose of this study is to assess the relationship between faculty familiarity with residents and faculty entrustment. MATERIALS AND METHODS: Researchers observed and rated entrustment behaviors using OpTrust, September 2015-June 2017 at Michigan Medicine. Faculty familiarity with resident was measured on a 1-4 scale (1 = not familiar, 4 = extremely familiar). ANOVA and Sidak adjusted multiple comparisons were used to assess the relationship between faculty familiarity and faculty entrustment. RESULTS: 56 faculty and 73 residents were observed across 225 surgical cases. Faculty entrustment scores increased to 2.48 when resident familiarity was reported as "slightly familiar". Faculty entrustment scores for "moderately familiar" increased to 2.57. Faculty entrustment scores for "extremely familiar" increased to 2.84. CONCLUSIONS: We found a positive relationship between faculty familiarity and entrustment. These findings support greater continuity in faculty/resident relationships. Longitudinal contact allows learners to be granted progressive entrustment. SUMMARY: This study demonstrates a positive relationship between faculty familiarity with residents and an increase in intraoperative entrustment. These findings support greater continuity in faculty/resident relationships.

Intravascular ultrasound as a novel tool for the diagnosis and targeted treatment of functional popliteal artery entrapment syndrome.

Functional popliteal artery entrapment syndrome can be difficult to diagnose, as the imaging modalities presently employed are designed to detect anatomic entrapment. We describe a novel imaging technique to aid in diagnosis in this cohort. A 22-year-old cyclist presented with exercise-limiting claudication. Magnetic resonance angiography with provocative maneuvers was nondiagnostic. Digital subtraction angiography revealed long-segment occlusion of the popliteal artery with plantar flexion; however, the specific site of compression remained unclear. Intravascular ultrasound allowed specific localization of compression and further confirmed the diagnosis. Thus, we report this as an adjunctive imaging modality to definitively diagnose functional popliteal artery entrapment syndrome and to assist in operative planning.

Internal iliac venous aneurysm associated with pelvic venous insufficiency.

Aneurysmal disease of the internal iliac vein is rare, with no standard indication for or accepted modality of treatment. Here we report an instance of unilateral, primary left internal iliac venous aneurysm and associated pelvic venous insufficiency. Following extensive workup for alternative causes, the aneurysm and left gonadal vein were coil embolized with good effect.

Notch Regulates Macrophage-Mediated Inflammation in Diabetic Wound Healing.

Macrophages are essential immune cells necessary for regulated inflammation during wound healing. Recent studies have identified that Notch plays a role in macrophage-mediated inflammation. Thus, we investigated the role of Notch signaling on wound macrophage phenotype and function during normal and diabetic wound healing. We found that Notch receptor and ligand expression are dynamic in wound macrophages during normal healing. Mice with a myeloid-specific Notch signaling defect (DNMAMLfloxedLyz2Cre+ ) demonstrated delayed early healing (days 1-3) and wound macrophages had decreased inflammatory gene expression. In our physiologic murine model of type 2 diabetes (T2D), Notch receptor expression was significantly increased in wound macrophages on day 6, following the initial inflammatory phase of wound healing, corresponding to increased inflammatory cytokine expression. This increase in Notch1 and Notch2 was also observed in human monocytes from patients with T2D. Further, in prediabetic mice with a genetic Notch signaling defect (DNMAMLfloxedLyz2Cre+ on a high-fat diet), improved wound healing was seen at late time points (days 6-7). These findings suggest that Notch is critical for the early inflammatory phase of wound healing and directs production of macrophage-dependent inflammatory mediators. These results identify that canonical Notch signaling is important in directing macrophage function in wound repair and define a translational target for the treatment of non-healing diabetic wounds.

The Histone Methyltransferase MLL1 Directs Macrophage-Mediated Inflammation in Wound Healing and Is Altered in a Murine Model of Obesity and Type 2 Diabetes.

Macrophages are critical for the initiation and resolution of the inflammatory phase of wound repair. In diabetes, macrophages display a prolonged inflammatory phenotype in late wound healing. Mixed-lineage leukemia-1 (MLL1) has been shown to direct gene expression by regulating nuclear factor-κB (NF-κB)-mediated inflammatory gene transcription. Thus, we hypothesized that MLL1 influences macrophage-mediated inflammation in wound repair. We used a myeloid-specific Mll1 knockout (Mll1f/fLyz2Cre+ ) to determine the function of MLL1 in wound healing. Mll1f/fLyz2Cre+ mice display delayed wound healing and decreased wound macrophage inflammatory cytokine production compared with control animals. Furthermore, wound macrophages from Mll1f/fLyz2Cre+ mice demonstrated decreased histone H3 lysine 4 trimethylation (H3K4me3) (activation mark) at NF-κB binding sites on inflammatory gene promoters. Of note, early wound macrophages from prediabetic mice displayed similarly decreased MLL1, H3K4me3 at inflammatory gene promoters, and inflammatory cytokines compared with controls. Late wound macrophages from prediabetic mice demonstrated an increase in MLL1, H3K4me3 at inflammatory gene promoters, and inflammatory cytokines. Prediabetic macrophages treated with an MLL1 inhibitor demonstrated reduced inflammation. Finally, monocytes from patients with type 2 diabetes had increased Mll1 compared with control subjects without diabetes. These results define an important role for MLL1 in regulating macrophage-mediated inflammation in wound repair and identify a potential target for the treatment of chronic inflammation in diabetic wounds.