Findings on Repeat Posttraumatic Brain Computed Tomography Scans in Older Patients With Minimal Head Trauma and the Impact of Existing Antithrombotic Use.

STUDY OBJECTIVE: Evaluate the utility of routine rescanning of older, mild head trauma patients with an initial negative brain computed tomography (CT), who is on a preinjury antithrombotic (AT) agent by assessing the rate of delayed intracranial hemorrhage (dICH), need for surgery, and attributable mortality. METHODS: Participating centers were trained and provided data collection instruments per institutional review board-approved protocols. Data were obtained from manual chart review and electronic medical record download. Adults ≥55 years seen at Level I/II Trauma Centers, between 2017 and 2019 with suspected head trauma, Glasgow Coma Scale 14 to 15, negative initial brain CT, and no other Abbreviated Injury Scale injuries >2 were identified, grouped by preinjury AT therapy (AT- or AT+) and compared on dICH rate, need for operative neurosurgical intervention, and attributable mortality using univariate analysis (α=.05). RESULTS: A total of 2,950 patients from 24 centers were enrolled; 280 (9.5%) had a repeat brain CT. In those rescanned, the dICH rate was 15/126 (11.9%) for AT- and 6/154 (3.9%) in AT+. Assuming nonrescanned patients did not suffer clinically meaningful dICH, the dICH rate would be 15/2001 (0.7%) for AT- and 6/949 (0.6%) for AT+. No surgical operations were done for dICH. All-cause mortality was 9/2950 (0.3%) and attributable mortality was 1/2950 (0.03%). The attributable death was an AT+, dICH patient whose family declined intervention. CONCLUSION: In older patients with an initial Glasgow Coma Scale of 14 to 15 and a negative initial brain CT scan, the dICH rate is low (<1%) and of minimal clinical consequence, regardless of AT use. In addition, no patient had operative neurosurgical intervention. Therefore, routine rescanning is not supported based on the results of this study.

Predictors for Direct to Operating Room Admission in Severe Trauma.

BACKGROUND: Protocols for expediting critical trauma patients directly from the helipad to the operating room tend to vary by center, rely heavily on physician gestalt, and lack supporting evidence. We evaluated a population of severely injured trauma patients with the aim of determining objective factors associated with the need for immediate surgical intervention. METHODS: All highest-activation trauma patients transported by air ambulance between 1/1/16 and 12/31/17 were enrolled retrospectively. Transfer, pediatric, isolated burn, and isolated head trauma patients were excluded. Patients who underwent emergency general surgery within 30 min of arrival without the aid of cross-sectional imaging were compared to the remainder of the cohort. RESULTS: Of the 863 patients who were enrolled, 85 (10%) spent less than 30 min in the emergency department (ED) before undergoing an emergency operation. The remaining 778 patients (90%) formed the comparison group. The ED ≤ 30 min group had a higher percentage of penetrating injuries, lower blood pressure, and was more likely to have a positive FAST exam. The "Direct to Operating Room" (DTOR) score is a predictive scoring system devised to identify patients most likely to benefit from bypassing the ED. The odds ratio of emergency operation within 30 min of hospital arrival increased by 2.71 (95% confidence interval 2.23-3.29; P < 0.001) for every 1-point increase in DTOR score. CONCLUSIONS: Trauma patients with profound hypotension or acidosis and positive FAST were more likely to require surgery within 30 min of hospital presentation. Use of a scoring system may allow early identification of these patients in the prehospital setting by nonphysician providers.

Safety profile and impact of low-titer group O whole blood for emergency use in trauma.

PURPOSE: Following US military implementation of a cold-stored whole blood program, several US trauma centers have begun incorporating uncrossmatched, group O cold-stored whole blood into civilian trauma resuscitation. We set out to evaluate the safety profile, transfusion reactions events, and impact of low-titer group O whole blood (LTO-WB) at our center. METHODS: In November 2017, we added LTO-WB to each of our helicopters and to our emergency department (ED) refrigerator, alongside that of existing red blood cells and plasma. We collected information on all patients with trauma receiving prehospital or ED transfusion of uncrossed, emergency release blood products between November 2017 and June 2018. Patients were divided into those receiving any LTO-WB and those receiving only red blood cell and or plasma (COMP). Serial hemolysis panels were obtained at 3 hours, 24 hours, and 48 hours. All data were run using STATA 12.1. Statistical significance was set at p < 0.05. RESULTS: One hundred ninety-eight patients received LTO-WB and 152 patients received COMP. There were no differences in age, sex, or mechanism. The LTO-WB patients had higher chest Abbreviated Injury Scale scores (median, 3 vs. 2; p = 0.027), as well as worse arrival base excess (median, -7 vs. -5; p = 0.014) and lactate (5.1 vs. 3.5; p < 0.001). The LTO-WB patients received less post-ED blood products than the COMP patients (median, 0 vs. 3; p = 0.001). There was no difference in survival (LTO-WB, 73%; COMP, 74%; p = 0.805). There were only two suspected transfusion reactions, both in the COMP group (p = 0.061). There was no difference in hemolysis panel values. Controlling for age, severity of injury, and prehospital physiology, LTO-WB was associated with a 53% reduction in post-ED blood product transfusion (odds ratio, 0.47; 0.23-0.94 95% CI; p = 0.033) and two-fold increase in likelihood of survival (odds ratio, 2.19; 1.01-4.76 95% CI; p = 0.047). CONCLUSION: Low-titer group O whole blood has similar evidence of laboratory hemolysis, similar transfusion reaction rates, and is associated with a reduction in post-ED transfusions and increase likelihood of survival. LEVEL OF EVIDENCE: Therapeutic, Level II.

The effect of damage control laparotomy on major abdominal complications: A matched analysis.

INTRODUCTION: Damage control laparotomy (DCL) for trauma is thought to be associated with increased abdominal complications. The purpose of this study is to determine the effect of DCL on abdominal complications by comparing two groups of trauma patients: DCL patients who were prospectively adjudicated to potentially being closed at the primary laparotomy (potential DEF or pDEF) and those who underwent definitive laparotomy (DEF). METHODS: The pDEF group was matched to DEF patients according to mechanism of injury, abdominal injury severity, operating room transfusions, and performance of a colon resection. The primary outcome was major abdominal complications (MAC), a composite variable. RESULTS: No statistically significant difference in the primary outcome, major abdominal complications, were seen (pDEF 19% versus DEF 56%, p = 0.066). The pDEF group was more likely to have a fascial dehiscence (38% versus 0%, p = 0.018), and to be re-opened after fascial closure (38% versus 0%, p = 0.018). CONCLUSION: Damage control laparotomy was associated with clinically but not statistically significant increase in rates of MAC. Increased numbers of patients to analyze in this fashion is needed.

The trauma center is too late: Major limb trauma without a pre-hospital tourniquet has increased death from hemorrhagic shock.

BACKGROUND: To date, no civilian studies have demonstrated that pre-hospital (PH) tourniquets improve survival. We hypothesized that late, trauma center (TC) tourniquet use would increase death from hemorrhagic shock compared to early (PH) placement. METHODS: All patients arriving to a Level 1, urban TC between October 2008 and January 2016 with a tourniquet placed before (T-PH) or after arrival to the TC (T-TC) were evaluated. Cases were assigned the following designations: indicated (absolute indication [vascular injury requiring repair/ligation, operation within 2 hours for extremity injury, or traumatic amputation] or relative indication [major musculoskeletal/soft tissue injury requiring operation 2-8 hours after arrival, documented large blood loss]) or non-indicated. Outcomes were death from hemorrhagic shock, physiology upon arrival to the TC, and massive transfusion requirements. After univariate analysis, logistic regression was carried out to assess independent predictors of death from hemorrhagic shock. RESULTS: A total of 306 patients received 326 tourniquets for injuries to 157 upper and 147 lower extremities. Two hundred eighty-one (92%) had an indication for placement. Seventy percent of patients had a blunt mechanism of injury. T-TC patients arrived with a lower systolic blood pressure (SBP, 101 [86, 123] vs. 125 [100, 145] mm Hg, p < 0.001), received more transfusions in the first hour of arrival (55% vs. 34%, p = 0.02), and had a greater mortality from hemorrhagic shock (14% vs. 3.0%, p = 0.01). When controlling for year of admission, mechanism of injury and shock upon arrival (SBP ≤90 mm Hg or HR ≥120 bpm or base deficit ≤ 4) indicated T-TC had a 4.5-fold increased odds of death compared to T-PH (OR 4.5, 95% CI 1.23-16.4, p = 0.02). CONCLUSIONS: Waiting until TC arrival to control hemorrhage with a tourniquet was associated with worsened blood pressure and increased transfusion within the first hour of arrival. In routine civilian trauma patients, delaying to T-TC was associated with 4.5-fold increased odds of mortality from hemorrhagic shock. LEVEL OF EVIDENCE: Level IV.

Microsomal triglyceride transfer protein contributes to lipid droplet maturation in adipocytes.

Previous studies in our laboratory have established the presence of MTP in both white and brown adipose tissue in mice as well as in 3T3-L1 cells. Additional studies demonstrated an increase in MTP levels as 3T3-L1 cells differentiate into adipocytes concurrent with the movement of MTP from the juxtanuclear region of the cell to the surface of lipid droplets. This suggested a role for MTP in lipid droplet biogenesis and/or maturation. To probe the role of MTP in adipocytes, we used a Cre-Lox approach with aP2-Cre and Adipoq-Cre recombinase transgenic mice to knock down MTP expression in brown and white fat of mice. MTP expression was reduced approximately 55% in white fat and 65-80% in brown fat. Reducing MTP expression in adipose tissue had no effect on weight gain or body composition, whether the mice were fed a regular rodent or high fat diet. In addition, serum lipids and unesterified fatty acid levels were not altered in the knockdown mice. Importantly, decreased MTP expression in adipose tissue was associated with smaller lipid droplets in brown fat and smaller adipocytes in white fat. These results combined with our previous studies showing MTP lipid transfer activity is not necessary for lipid droplet initiation or growth in the early stages of differentiation, suggest that a structural feature of the MTP protein is important in lipid droplet maturation. We conclude that MTP protein plays a critical role in lipid droplet maturation, but does not regulate total body fat accumulation.

Decreasing the Use of Damage Control Laparotomy in Trauma: A Quality Improvement Project.

BACKGROUND: Our institution has published damage control laparotomy (DCL) rates of 30% and documented the substantial morbidity associated with the open abdomen. The purpose of this quality improvement (QI) project was to decrease the rate of DCL at a busy, Level I trauma center in the US. STUDY DESIGN: A prospective cohort of all emergent trauma laparotomies from November 2013 to October 2015 (QI group) was followed. The QI intervention was multifaceted and included audit and feedback for every DCL case. Morbidity and mortality of the QI patients were compared with those from a published control (control group: emergent laparotomy from January 2011 to October 2013). RESULTS: A significant decrease was observed immediately on beginning the QI project, from a 39% DCL rate in the control period to 23% in the QI group (p < 0.001). This decrease was sustained over the 2-year study period. There were no differences in demographics, Injury Severity Score, or transfusions between the groups. No differences organ/space infection (control 16% vs QI 12%; p = 0.15), fascial dehiscence (6% vs 8%; p = 0.20), unplanned relaparotomy (11% vs 10%; p = 0.58), or mortality (9% vs 10%; p = 0.69) were observed. The reduction in use resulted in a decrease of 68 DCLs over the 2-year period. There was a further reduction in the rate of DCL to 17% after completion of the QI project. CONCLUSIONS: A QI initiative rapidly changed the use of DCL and improved quality of care by decreasing resource use without an increase morbidity or mortality. This decrease was sustained during the QI period and further improved upon after its completion.

Stapled versus hand-sewn: A prospective emergency surgery study. An American Association for the Surgery of Trauma multi-institutional study.

BACKGROUND: Data from the trauma patient population suggests handsewn (HS) anastomoses are superior to stapled (ST). A recent retrospective study in emergency general surgery (EGS) patients had similar findings. The aim of the current study was to evaluate HS and ST anastomoses in EGS patients undergoing urgent/emergent operations. METHODS: The study was sponsored by the American Association for the Surgery of Trauma Multi-Institutional Studies Committee. Patients undergoing urgent/emergent bowel resection for EGS pathology were prospectively enrolled from July 22, 2013 to December 31, 2015. Patients were grouped by HS/ST anastomoses, and variables were collected. The primary outcome was anastomotic failure. Similar to other studies, anastomotic failure was evaluated at the anastomosis level. Multivariable logistic regression was performed controlling for age and risk factors for anastomotic failure. RESULTS: Fifteen institutions enrolled a total of 595 patients with 649 anastomoses (253 HS and 396 ST). Mean age was 61 years, 51% were men, 7% overall mortality. Age and sex were the same between groups. The overall anastomotic failure rate was 12.5%. The HS group had higher lactate, lower albumin, and were more likely to be on vasopressors. Hospital and intensive care unit days, as well as mortality, were greater in the HS group. Anastomotic failure rates and operative time were equivalent for HS and ST. On multivariate regression, the presence of contamination at initial resection (odds ratio, 1.965; 95% confidence interval, 1.183-3.264) and the patient being managed with open abdomen (odds ratio, 2.529; 95% confidence interval, 1.492-4.286) were independently associated with anastomotic failure, while the type of anastomosis was not. CONCLUSION: EGS patients requiring bowel resection and anastomosis are at high risk for anastomotic failure. The current study illustrates an apparent bias among acute care surgeons to perform HS techniques in higher-risk patients. Despite the individualized application of technique for differing patient populations, the risk of anastomotic failure was equivalent when comparing HS and ST anastomoses. LEVEL OF EVIDENCE: Therapeutic study, level II.

Safety and Appropriateness of Tourniquets in 105 Civilians.

BACKGROUND: The United States military considers tourniquets to be effective for controlling bleeding from major limb trauma. The purpose of this study was to assess whether tourniquets are safely applied to the appropriate civilian patient with major limb trauma of any etiology. METHODS: Following IRB approval, patients arriving to a level-1 trauma center between October 2008 and May 2013 with a prehospital (PH) or emergency department (ED) tourniquet were reviewed. Cases were assigned the following designations: absolute indication (operation within 2 hours for limb injury, vascular injury requiring repair/ligation, or traumatic amputation); relative indication (major musculoskeletal/soft-tissue injury requiring operation 2-8 hours after arrival, documented large blood loss); and non-indicated. Patients with absolute or relative indications for tourniquet placement were defined as indicated, while the remaining were designated as non-indicated. Complications potentially associated with tourniquets, including amputation, acute renal failure, compartment syndrome, nerve palsies, and venous thromboembolic events, were adjudicated by orthopedic, hand or trauma surgical staff. Univariate analysis was performed to compare patients with indicated versus non-indicated tourniquet placement. RESULTS: A total of 105 patients received a tourniquet for injuries sustained via sharp objects, i.e., glass or knives (32%), motor vehicle collisions (30%), or other mechanisms (38%). A total of 94 patients (90%) had indicated tourniquet placement; 41 (44%) of which had a vascular injury. Demographics, mechanism, transport, and vitals were similar between patients that had indicated or non-indicated tourniquet placement. 48% of the indicated tourniquets placed PH were removed in the ED, compared to 100% of the non-indicated tourniquets (p < 0.01). The amputation rate was 32% among patients with indicated tourniquet placement (vs. 0%; p = 0.03). Acute renal failure (3.2 vs. 0%, p = 0.72), compartment syndrome (2.1 vs. 0%, p = 0.80), nerve palsies (5.3 vs. 0%; p = 0.57), and venous thromboembolic events (9.1 vs. 8.5%; p = 0.65) and were similar in patients that had indicated compared to non-indicated tourniquet placement. After adjudication, no complication was a result of tourniquet use. CONCLUSION: The current study suggests that PH and ED tourniquets are used safely and appropriately in civilians with major limb trauma that occur via blunt and penetrating mechanisms.

Control the damage: morbidity and mortality after emergent trauma laparotomy.

BACKGROUND: Damage control laparotomy (DCL) is performed for physiologically deranged patients. Recent studies suggest overutilization of DCL, which may be associated with potentially iatrogenic complications. METHODS: We conducted a retrospective study of trauma patients over a 2-year period that underwent an emergent laparotomy and received preoperative blood products. The group was divided into definitive laparotomy and DCL. RESULTS: A total of 237 received were included: 78 in definitive laparotomy group, 144 in the DCL group, and 15 who died in the operating room. The DCL group was more severely injured and required more transfusions. After propensity score matching, DCL was associated with an 18% increase in hospital mortality, a 13% increase in ileus, and a 7% increase in enteric suture line failure, an 11% increase in fascial dehiscence, and a 19% increase in superficial surgical site infection. CONCLUSIONS: The potential overuse of DCL unnecessarily exposes patients to increased morbidity and mortality.

Predicting and enhancing American Board of Surgery In-Training Examination performance: does writing questions really help?

BACKGROUND: The generative learning model posits that individuals remember content they have generated better than materials created by others. The goals of this study were to evaluate question generation as a study method for the American Board of Surgery In-Training Examination (ABSITE) and determine whether practice test scores and other data predict ABSITE performance. METHODS: Residents (n = 206) from 6 general surgery programs were randomly assigned to one of the two study conditions. One group wrote questions for practice examinations. All residents took 2 practice examinations. RESULTS: There was not a significant effect of writing questions on ABSITE score. Practice test scores, United States Medical Licensing Examination Step 1 scores, and previous ABSITE scores were significantly correlated with ABSITE performance. CONCLUSIONS: The generative learning model was not supported. Performance on practice tests and other data can be used for early identification of residents at risk of performing poorly on the ABSITE.

Microsomal Triglyceride Transfer Protein (MTP) Associates with Cytosolic Lipid Droplets in 3T3-L1 Adipocytes.

Lipid droplets are intracellular energy storage organelles composed of a hydrophobic core of neutral lipid, surrounded by a monolayer of phospholipid and a diverse array of proteins. The function of the vast majority of these proteins with regard to the formation and/or turnover of lipid droplets is unknown. Our laboratory was the first to report that microsomal triglyceride transfer protein (MTP), a lipid transfer protein essential for the assembly of triglyceride-rich lipoproteins, was expressed in adipose tissue of humans and mice. In addition, our studies suggested that MTP was associated with lipid droplets in both brown and white fat. Our observations led us to hypothesize that MTP plays a key role in lipid droplet formation and/or turnover. The objective of these studies was to gain insight into the function of MTP in adipocytes. Using molecular, biochemical, and morphologic approaches we have shown: 1) MTP protein levels increase nearly five-fold as 3T3-L1 cells differentiate into adipocytes. 2) As 3T3-L1 cells undergo differentiation, MTP moves from the juxtanuclear region of the cell to the surface of lipid droplets. MTP and perilipin 2, a major lipid droplet surface protein, are found on the same droplets; however, MTP does not co-localize with perilipin 2. 3) Inhibition of MTP activity has no effect on the movement of triglyceride out of the cell either as a lipid complex or via lipolysis. 4) MTP is found associated with lipid droplets within hepatocytes from human fatty livers, suggesting that association of MTP with lipid droplets is not restricted to adipocytes. In summary, our data demonstrate that MTP is a lipid droplet-associated protein. Its location on the surface of the droplet in adipocytes and hepatocytes, coupled with its known function as a lipid transfer protein and its increased expression during adipocyte differentiation suggest a role in lipid droplet biology.

Damage-control resuscitation increases successful nonoperative management rates and survival after severe blunt liver injury.

BACKGROUND: Nonoperative multidisciplinary management for severe (American Association for the Surgery of Trauma Grades IV and V) liver injury has been used for two decades. We have previously shown that Damage Control Resuscitation (DCR) using low-volume, balanced resuscitation improves survival of severely injured trauma patients; however, little attention has been paid to organ-specific outcomes. We wanted to determine if implementation of DCR has improved survival and successful nonoperative management after severe blunt liver injury. METHODS: A retrospective study was performed on all adult trauma patients with severe blunt liver injury who were admitted from 2005 to 2011. Patients were divided into pre-DCR (2005-2008) and DCR (2009-2011) groups. Patients who died before leaving the emergency department (ED) were excluded. Outcomes (resuscitation products used, survival, and length of stay) were then compared by univariate and multivariate analyses. RESULTS: Between 2005 and 2011, 29,801 adult trauma patients were admitted, and 1,412 (4.7%) experienced blunt liver injury. Of these, 244 (17%) sustained Grade IV and V injuries, with 206 patients surviving to leave the ED. The pre-DCR group (2005-2008) was composed of 108 patients, and the DCR group (2009-2011) had 98 patients. The groups were not different in demographics as well as prehospital and ED vital signs or Injury Severity Score (ISS). No change in operative or interventional radiology techniques occurred in this time frame. The DCR cohort had an increase in successful nonoperative management (from 54% to 74%, p < 0.01) as well as a reduction in initial 24-hour packed red blood cell (median, from 13 U to 6.5 U; p < 0.01), plasma (median, from 13 U to 8 U; p < 0.01), and crystalloid (median, from 5,800 mL to 4,100 mL; p < 0.01) administration. The DCR treatment was associated with improved survival, from 73% to 94% (p < 0.01). CONCLUSION: In patients with severe blunt liver injury, DCR was associated with less crystalloid and blood product use, a higher successful nonoperative management rate, and improved survival. Resuscitation technique may improve outcomes after severe liver injury. LEVEL OF EVIDENCE: Therapeutic/care management, level III.

Tort reform is associated with more medical board complaints and disciplinary actions.

BACKGROUND: Previous reports have confirmed that comprehensive tort reform in Texas (enacted in 2003) was associated with fewer lawsuits and less litigation-associated cost. We hypothesized that complaints to the Texas Medical Board (TMB) increased after tort reform. STUDY DESIGN: To test this hypothesis, we compared complaints, investigations, disciplinary actions, and penalties against physicians before and after comprehensive state tort reform measures were adopted. Data were obtained from the TMB for a 15-year period (1996 to 2010). RESULTS: When comparing the period before tort reform (1996 to 2002) with the period after tort reform (2004 to 2010), TMB complaints increased 13%; investigations opened increased 33%, disciplinary actions increased 96%, license revocations or surrenders increased 47%, and financial penalties increased 367%. All of these increases were statistically significant (p ≤ 0.01). CONCLUSIONS: After tort reform in Texas, the total number of complaints, investigations, disciplinary decisions, license revocations or surrenders, and financial penalties from the TMB significantly increased. In Texas, tort reform was accompanied by legislatively directed, enhanced oversight and activity of the authority (TMB) charged with regulation of the medical profession.

BMP2 signals loss of epithelial character in epicardial cells but requires the Type III TGFß receptor to promote invasion.

Coronary vessel development depends on a subpopulation of epicardial cells that undergo epithelial to mesenchymal transformation (EMT) and invade the subepicardial space and myocardium. These cells form the smooth muscle of the vessels and fibroblasts, but the mechanisms that regulate these processes are poorly understood. Mice lacking the Type III Transforming Growth Factor ß Receptor (TGFßR3) die by E14.5 due to failed coronary vessel development accompanied by reduced epicardial cell invasion. BMP2 signals via TGFßR3 emphasizing the importance of determining the relative contributions of the canonical BMP signaling pathway and TGFßR3-dependent signaling to BMP2 responsiveness. Here we examined the role of TGFßR3 in BMP2 signaling in epicardial cells. Whereas TGFß induced loss of epithelial character and smooth muscle differentiation, BMP2 induced an ALK3-dependent loss of epithelial character and modestly inhibited TGFß-stimulated differentiation. Tgfbr3(-/-) cells respond to BMP2 indicating that TGFßR3 is not required. However, Tgfbr3(-/-) cells show decreased invasion in response to BMP2 and overexpression of TGFßR3 in Tgfbr3(-/-) cells rescued invasion. Invasion was dependent on ALK5, ALK2, ALK3, and Smad4. Expression of TGFßR3 lacking the 3 C-terminal amino acids required to interact with the scaffolding protein GIPC (GAIP-interacting protein, C terminus) did not rescue. Knockdown of GIPC in Tgfbr3(+/+) or Tgfbr3(-/-) cells rescued with TGFßR3 decreased BMP2-stimulated invasion confirming a requirement for TGFßR3/GIPC interaction. Our results reveal the relative roles of TGFßR3-dependent and TGFßR3-independent signaling in the actions of BMP2 on epicardial cell behavior and demonstrate the critical role of TGFßR3 in mediating BMP2-stimulated invasion.

The cytoplasmic domain of TGFßR3 through its interaction with the scaffolding protein, GIPC, directs epicardial cell behavior.

The epicardium is a major contributor of the cells that are required for the formation of coronary vessels. Mice lacking both copies of the gene encoding the Type III Transforming Growth Factor ß Receptor (TGFßR3) fail to form the coronary vasculature, but the molecular mechanism by which TGFßR3 signals coronary vessel formation is unknown. We used intact embryos and epicardial cells from E11.5 mouse embryos to reveal the mechanisms by which TGFßR3 signals and regulates epicardial cell behavior. Analysis of E13.5 embryos reveals a lower rate of epicardial cell proliferation and decreased epicardially derived cell invasion in Tgfbr3(-/-) hearts. Tgfbr3(-/-) epicardial cells in vitro show decreased proliferation and decreased invasion in response to TGFß1 and TGFß2. Unexpectedly, loss of TGFßR3 also decreases responsiveness to two other important regulators of epicardial cell behavior, FGF2 and HMW-HA. Restoring full length TGFßR3 in Tgfbr3(-/-) cells rescued deficits in invasion in vitro in response TGFß1 and TGFß2 as well as FGF2 and HMW-HA. Expression of TGFßR3 missing the 3 C-terminal amino acids that are required to interact with the scaffolding protein GIPC1 did not rescue any of the deficits. Overexpression of GIPC1 alone in Tgfbr3(-/-) cells did not rescue invasion whereas knockdown of GIPC1 in Tgfbr3(+/+) cells decreased invasion in response to TGFß2, FGF2, and HMW-HA. We conclude that TGFßR3 interaction with GIPC1 is critical for regulating invasion and growth factor responsiveness in epicardial cells and that dysregulation of epicardial cell proliferation and invasion contributes to failed coronary vessel development in Tgfbr3(-/-) mice.

Primary and immortalized mouse epicardial cells undergo differentiation in response to TGFbeta.

Cells derived from the epicardium are required for coronary vessel development. Transforming growth factor beta (TGFbeta) induces loss of epithelial character and smooth muscle differentiation in chick epicardial cells. Here, we show that epicardial explants from embryonic day (E) 11.5 mouse embryos incubated with TGFbeta1 or TGFbeta2 lose epithelial character and undergo smooth muscle differentiation. To further study TGFbeta Signaling, we generated immortalized mouse epicardial cells. Cells from E10.5, 11.5, and 13.5 formed tightly packed epithelium and expressed the epicardial marker Wilm's tumor 1 (WT1). TGFbeta induced the loss of zonula occludens-1 (ZO-1) and the appearance of SM22alpha and calponin consistent with smooth muscle differentiation. Inhibition of activin receptor-like kinase (ALK) 5 or p160 rho kinase activity prevented the effects of TGFbeta while inhibition of p38 mitogen activated protein (MAP) kinase did not. These data demonstrate that TGFbeta induces epicardial cell differentiation and that immortalized epicardial cells provide a suitable model for differentiation.

Prophylactic bilateral salpingo-oopherectomy in a 17-year-old with Frasier syndrome reveals gonadoblastoma and seminoma: a case report.

Mutations in the Wilms' tumor gene are present in children with Frasier syndrome, Denys-Drash syndrome, WAGR syndrome, and some cases of Wilms' tumor. The Wilms' tumor gene product, WT1, is necessary for normal urogenital development. Frasier syndrome is an association between focal segmental glomerulosclerosis, beginning in the second and third decade, male to female sex reversal, and dysgenetic gonads. We report a case of Frasier syndrome in a 17-year-old adolescent girl with renal failure, kidney transplant, and dysgenetic gonads, with development of gonadoblastoma and dysgerminoma (seminoma). The diagnosis of Frasier syndrome was based on nephrotic syndrome with diffuse mesangial sclerosis leading to chronic renal failure, dysgenetic gonads, 46 XY karyotype in a phenotypic female, and a mutation in the Wilms' tumor gene. Prophylactic laparoscopic bilateral salpingo-oopherectomy revealed gonadoblastoma and seminoma in opposite atrophic ovaries as well as a hypoplastic uterus. Early prophylactic resection of dysgenetic gonads is indicated in children with Frasier syndrome to prevent the development of germ cell malignancy.