Faculty Bibliography

BACKGROUND:Anastomotic leak is a major source of morbidity in colorectal operations and has become an area of interest in performance metrics. It is unclear whether anastomotic leak is associated primarily with surgeons' technical performance or explained better by patient characteristics and institutional factors. We sought to establish if anastomotic leak could serve as a valid quality metric in colorectal operations by evaluating provider variation after adjusting for patient factors. METHODS:We performed a retrospective cohort study of colorectal resection patients in the Michigan Surgical Quality Collaborative. Clinically relevant patient and operative factors were tested for association with anastomotic leak. Hierarchical logistic regression was used to derive risk-adjusted rates of anastomotic leak. RESULTS:/L), and urgent/emergency operations were independently associated with anastomotic leak (C-statistic = 0.75). After accounting for patient and procedural risk factors, 5 hospitals had a significantly greater incidence of postoperative anastomotic leak. CONCLUSION:This population-based study shows that risk factors for anastomotic leak include male sex, obesity, tobacco use, immunosuppression, thrombocytosis, greater operative duration, and urgent/emergency operation; models including these factors predict most of the variation in anastomotic leak rates. This study suggests that anastomotic leak can serve as a valid metric that can identify opportunities for quality improvement.

BACKGROUND:Combined traumatic brain injury (TBI) and hemorrhagic shock (HS) is highly lethal. In previous models of combined TBI + HS, we showed that early resuscitation with fresh frozen plasma (FFP) improves neurologic outcomes. Delivering FFP, however, in austere environments is difficult. Lyophilized plasma (LP) is a logistically superior alternative to FFP, but data are limited regarding its efficacy for treatment of TBI. We conducted this study to determine the safety and long-term outcomes of early treatment with LP in a large animal model of TBI + HS. METHODS:Adult anesthetized swine underwent TBI and volume-controlled hemorrhage (40% blood volume) concurrently. After 2 hours of shock, animals were randomized (n = 5 per /group) to FFP or LP (1× shed blood) treatment. Serial blood gases were drawn, and thromboelastography was performed on citrated, kaolin-activated whole-blood samples. Five hours after treatment, packed red blood cells were administered, and animals recovered. A 32-point Neurologic Severity Score was assessed daily for 30 days (0 = normal, 32 = most severe injury). Cognitive functions were tested by training animals to retrieve food from color-coded boxes. Brain lesion size was measured on serial magnetic resonance imaging, and an autopsy was performed at 30 days. RESULTS:The severity of shock and the degree of resuscitation were similar in both groups. Administration of FFP and LP was well tolerated with no differences in reversal of shock or thromboelastography parameters. Animals in both groups displayed the worst Neurologic Severity Score on postoperative Day 1 with rapid recovery and return to baseline within 7 days of injury. Lesion size on Day 3 in FFP-treated animals was 645 ± 85 versus 219 ± 20 mm in LP-treated animals (p < 0.05). There were no differences in cognitive functions or delayed treatment-related complications. CONCLUSIONS:Early treatment with LP in TBI + HS is safe and provides neuroprotection that is comparable to FFP.

BACKGROUND:High doses of the histone deacetylase inhibitor valproic acid (VPA, 150-400 mg/kg) improve outcomes in animal models of lethal insults. We are conducting a US Food and Drug Administration-approved Phase I, double-blind, placebo-controlled trial to evaluate the safety and tolerability of ascending doses of VPA in human volunteers. We hypothesized that VPA would induce significant changes in the proteome of healthy humans when given at doses lower than those used in prior animal studies. METHODS:Peripheral blood mononuclear cells were obtained from three healthy subjects randomized to receive VPA (120 mg/kg over 1 hour) at baseline and at 4 and 8 hours following infusion. Detailed proteomic analysis was performed using 1D gel electrophoresis, liquid chromatography, and mass spectrometry. Proteins with differential expression were chosen for functional annotation and pathway analysis using Ingenuity Pathway Analysis (Qiagen GmbH, Hilden, Germany) and Panther Gene Ontology. RESULTS:A total of 3,074 unique proteins were identified. The average number of proteins identified per sample was 1,716 ± 459. There were a total of 140 unique differentially expressed proteins (p < 0.05). There was a minor and inconsistent increase in histone and nonhistone protein acetylation. Functional annotation showed significant enrichment of apoptosis (p = 3.5E-43), cell death (p = 9.9E-72), proliferation of cells (p = 1.6E-40), dementia (p = 9.6E-40), amyloidosis (p = 6.3E-38), fatty acid metabolism (p = 4.6E-76), quantity of steroid (p = 4.2E-75), and cell movement (p = 1.9E-64). CONCLUSIONS:Valproic acid induces significant changes to the proteome of healthy humans when given at a dose of 120 mg/kg. It alters the expression of key proteins and pathways, including those related to cell survival, without significant modification of protein acetylation. In the next part of the ongoing Phase I trial, we will study the effects of VPA on trauma patients in hemorrhagic shock. LEVEL OF EVIDENCE:Therapeutic study, level V.

BACKGROUND:We recently discovered that Tubastatin-A, a histone deacetylase (HDAC6) inhibitor, can improve survival in a rodent model of hemorrhagic shock (HS), but mechanisms remain poorly defined. In this study, we investigated whether Tubastatin-A could protect intestinal tight junction (TJ) in HS. METHODS:In an in-vivo study with Wistar-Kyoto rats, the rats underwent HS (40% blood loss) followed by Tubastatin-A (70 mg/kg) treatment, without fluid resuscitation. The experimental groups were (1) sham (no hemorrhage, no treatment), (2) control (hemorrhage, without treatment), and (3) treatment (hemorrhage with Tubastatin-A administration). Six hours after hemorrhage, ileum was harvested. Whole cell lysate were analyzed for acetylated α-tubulin (Ac-tubulin), total tubulin, acetylated histone 3 at lysine 9 (Ac-H3K9), β-actin, claudin-3 and zonula occludens 1 (ZO-1) proteins by Western blot. Histological effects of Tubastatin-A on small bowel were examined. In an in-vitro study, human intestinal epithelial cells (Caco-2) were divided into three groups: (1) sham (normoxia), (2) control (anoxia, no treatment), and (3) treatment (anoxia, treatment with Tubastatin-A). After 12 hours in an anoxia chamber, the cells were examined for Ac-tubulin and Ac-H3K9, cellular viability, cytotoxicity, claudin-3 and ZO-1 protein expression, and transwell permeability study. RESULTS:Tubastatin-A treatment significantly attenuated HS-induced decreases of Ac-tubulin, Ac-H3K9, ZO-1 and claudin-3 proteins in small bowel in-vivo (p < 0.05). In cultured Caco-2 cells, anoxia significantly decreased cellular viability (p < 0.001) and increased cytotoxicity (p < 0.001) compared to the sham group, while Tubastatin-A treatment offered significant protection (p < 0.0001). Moreover, expression of claudin-3 was markedly decreased in vitro compared to the sham group, whereas this was significantly attenuated by Tubastatin-A (p < 0.05). Finally, anoxia markedly increased the permeability of Caco-2 monolayer cells (p < 0.05), while Tubastatin-A significantly attenuated the alteration (p < 0.05). CONCLUSION:Inhibition of HDAC6 can induce Ac-tubulin and Ac-H3K9, promote cellular viability, and prevent the loss of intestinal tight junction proteins during HS and anoxia.

Sartorius myoplasty (SM) has been used as an adjunct for soft tissue coverage in vascular groin wound complications. However, the reliability of SM as a primary muscle flap has been questioned. The purpose of this study is to determine the reliability of SM performed by vascular surgeons in the management of vascular groin wound complications. A retrospective review was performed on all patients who underwent SM from 1997 to 2012. The three indications for SM were prophylactic, infection, and noninfectious wound complication. Failure of SM was defined as operative reintervention for bleeding, persistent wound drainage, or infection. A total of 99 patients underwent 103 SM procedures. The patients were 43 per cent male and 57 per cent female; the mean age was 69 years. The indication for SM was infectious in 62 cases (60%), prophylactic in 21 cases (20%), and noninfectious in the remaining 20 cases. Failure of SM occurred in 11 cases (11%). Of these, salvage bypass and/or salvage muscle flap was required in eight cases (73%). When salvage bypass was required, extra-anatomic obturator bypass was performed in 80 per cent of cases. Salvage wound coverage included rectus abdominus flap (60%), rotational flap (20%), and skin grafting (20%).Seventy-three per cent of failures came from the infectious wound group. The most common reason for SM failure was hemorrhage (45%). In 82 per cent of the cases, the sartorius muscle was still viable at reoperation and was used for continued muscle coverage. SM performed by the vascular surgeon provides reliable soft tissue coverage for vascular groin wound complications and should be used as the primary muscle flap in the majority of patients. In cases of SM failure, the vascular surgeon should consider other more extensive muscle flap options.

Traumatic injuries and their sequelae represent a major source of mortality in the United States and globally. Initial treatment for shock, traumatic brain injury, and polytrauma is limited to resuscitation fluids to replace lost volume. To date, there are no treatments with inherent prosurvival properties. Our laboratory has investigated the use of histone deacetylase inhibitors (HDACIs) as pharmacological agents to improve survival. This class of drugs acts through posttranslational protein modifications and is a direct regulator of chromatin structure and function, as well as the function of numerous cytoplasmic proteins. In models of hemorrhagic shock and polytrauma, administration of HDACIs offers a significant survival advantage, even in the absence of fluid resuscitation. Positive results have also been shown in two-hit models of hemorrhage and sepsis and in hemorrhagic shock combined with traumatic brain injury. Accumulating data generated by our group and others continue to support the use of HDACIs for the creation of a prosurvival phenotype. With further research and clinical trials, HDACIs have the potential to be an integral tool in the treatment of trauma, especially in the prehospital phase.

BACKGROUND:Seven isoforms of histone deacetylase Class III have been reported - Sirtuin (SIRT) 1-7. We recently demonstrated that EX-527, an inhibitor of SIRT1, reduces mortality in a mouse model of lethal-cecal-ligationand- puncture (CLP)-induced septic shock. Our present study was aimed at determining whether selective inhibition of SIRT2, with AGK2, would decrease animal death and attenuate the inflammatory response in a septic model. METHODS:Experiment I: C57BL/6J mice were intraperitoneally given either AGK2 (82 mg/kg) in dimethyl sulfoxide (DMSO) or DMSO alone, and 2 h later subjected to CLP. Survival was monitored for 240 hours. Experiment II: mice treated the same way as Experiment I, were grouped into (i) DMSO vehicle, and (ii) AGK2, with sham mice (operating but without any treatment) serving as controls. Peritoneal fluid and peripheral blood were examined at 24 and 48 hours for cytokine production. Samples of blood at 48 h were also allocated to assess coagulability using Thrombelastography (TEG). Morphological changes of bone marrow were evaluated from long bones (femurs and tibias) with hematoxylin and eosin (H&E) staining. Bone marrow atrophy was quantified by a blinded pathologist. Experiment III: cytokines in supernatant of the cultured normal primary splenocytes were measured after the cells were stimulated by lipopolysaccharide and treated with or without AGK2 (10 µM) for 6 hours. RESULTS:AGK2 significantly reduced mortality and decreased levels of cytokines in blood (TNF-α: 298.3±24.6 vs 26.8±2.8 pg/ml, p=0.0034; IL-6: 633.4±82.8 vs 232.6±133.0 pg/ml, p=0.0344) and peritoneal fluid (IL-6: 704.8±67.7 vs 391.4±98.5 pg/ml, p=0.033) compared to vehicle control. Also, AGK2 suppressed the TNF-α and IL-6 production in the cultured splenocytes (TNF-α: 68.1±6.4 vs 23.9±2.8 pg/ml, p=0.0009; IL-6: 73.1±4.2 vs 49.6±3.0 pg/ml; p=0.0051). The TEG data showed that the mice subjected to CLP displayed prolonged fibrin formation and fibrin cross-linkage time, slower clot formation, decreased platelet function, and clot rigidity. AGK2 treatment was associated with dramatic improvements in fibrin cross-linkage and clot formation times, without a significant impact on the clot initiation parameters or platelet function. Additionally, AGK2 significantly attenuated the bone marrow atrophy (58.3±6.5 vs 30.0±8.2%, p=0.0262). CONCLUSION/CONCLUSIONS:Selective inhibition of SIRT2 significantly improves survival, and attenuates sepsis-associated "cytokine storm", coagulopathy, and bone marrow atrophy in a mouse model of lethal septic shock.

BACKGROUND:Endoscopic harvest of saphenous vein for infrainguinal arterial bypass decreases incision length and was initially documented to decrease wound complications without adversely affecting patency. However, recent studies have shown lower patency without a wound complication benefit. We sought to further define the wound complication and patency rates of endoscopic harvest compared with open harvest in infrainguinal arterial bypass procedures. METHODS:Infrainguinal bypasses performed from 2000 to 2011 were analyzed. Only procedures using a single segment of great saphenous vein were included. Cases were grouped according to endoscopic or open harvest and were frequency-matched for body mass index and diabetes. Baseline characteristics were compared. Univariate and multivariate analysis was performed to determine correlation of baseline data and harvest method on wound complications and patency. RESULTS:The study included 76 bypasses; 35 in the endoscopic harvest group and 41 in the open harvest group. Baseline characteristics between the endoscopic and open harvest groups were not significantly different, with the exception of mean age, which was older in the endoscopic harvest group, and carotid artery disease, which was more common in the open harvest group. There was no significant difference between endoscopic and open harvest in 30-day wound complication rates (29% vs 27%; P = .87) or in the other perioperative variables, aside from decreased narcotic use in the endoscopic harvest group (P = .01). Mean follow-up was 747 days. There was no significant difference in 3-year primary (47% vs 49%; P = .8), 3-year primary-assisted (88% vs 73%; P = .1), or secondary patency rates (92% vs 76%; P = .09) at 3 years between the endoscopic and open harvest groups. High body mass index improved primary patency in the endoscopic harvest group (P = .02), but had no effect on patency in the open harvest group (P = .15). Patients requiring hemodialysis had increased risk for loss of primary assisted patency in both groups (endoscopic, P = .02; open, P = .02) and decreased secondary patency in the open harvest group (P = .04). CONCLUSIONS:Endoscopic and open harvest techniques for infrainguinal arterial bypass provide similar rates of wound complications and bypass patency, whereas hemodialysis negatively affects patency after both harvest methods. Endoscopic harvest is associated with the need for less perioperative narcotics, suggesting a potential benefit of endoscopic harvest that deserves further study.

Although pancreatic beta-cell transplantation may serve as a potential cure for diabetes mellitus (DM), limited donor tissue availability poses a major challenge. Thus, there is a great demand to find new sources for pancreatic beta-cells. Here, we present a lentiviral vector-based approach to achieve beta-cell proliferation through the beta-cell-specific activation of the hepatocyte growth factor (HGF)/cmet signaling pathway. The methodology is based on the beta-cell-specific expression of a ligand-inducible, chimeric receptor (F36Vcmet), under transcriptional control of the promoter from the human insulin gene, and its ability to induce HGF/cmet signaling in the presence of a synthetic ligand (AP20187). High transduction efficiency of human pancreatic islets was achieved utilizing this approach with chimeric receptor expression confined to the beta-cell population. In addition, specific proliferation of human pancreatic beta-cells was induced utilizing this approach. Selective, regulated beta-cell expansion may help to provide greater availability of cells for transplantation in patients with DM.