Nationwide Analysis of Penetrating Thoracic Aortic Injury: Injury Patterns, Management, and Outcomes.

INTRODUCTION: Penetrating thoracic aortic injuries (PTAI) represent a rare form of thoracic trauma. Unlike blunt thoracic aortic injuries (BTAI), only scarce data, included in small case series, are currently available for PTAI. The purpose of this study was to describe injury patterns, surgical management, and outcomes of patients with PTAI and compare to those with BTAI. MATERIALS AND METHODS: A 9-y retrospective cohort study (2007-2015) was conducted using the National Trauma Data Bank. Patient demographics, injury profile, procedures performed, and patient outcomes were compared between the PTAI and BTAI group. RESULTS: A total of 2714 patients with PTAI and 14,037 patients with BTAI were identified. Compared to BTAI, PTAI patients were younger (28 versus 42 y, P < 0.001), more often male (89.1% versus 71.7%, P < 0.001), and more likely to arrive without signs of life (27.6% versus 7.5%, P < 0.001). PTAI patients had less associated injuries, overall, compared to those with BTAI; however, were more likely to have injuries to the esophagus, diaphragm, and heart. Patients with PTAI were less likely to undergo endovascular (5.8% versus 30.5%, P < 0.001) or open surgical repair (3.0% versus 4.2%, P < 0.001) compared to BTAI. While the large majority of PTAI patients expired before their hospital arrival or in the emergency department, the in-hospital mortality rate among those who survivedemergency department stay was 43.1%. CONCLUSIONS: Most patients with PTAI present to the hospital without any signs of life, and their overall mortality rate is extremely high. Only a small portion of PTAI patients who survived the initial resuscitation period underwent surgical interventions for thoracic aortic injuries. Further studies are still warranted to clarify the indications and types of surgical interventions for PTAI.

Matrix Gla Protein Levels Are Associated With Arterial Stiffness and Incident Heart Failure With Preserved Ejection Fraction.

OBJECTIVE: Arterial stiffness is a risk factor for cardiovascular disease, including heart failure with preserved ejection fraction (HFpEF). MGP (matrix Gla protein) is implicated in vascular calcification in animal models, and circulating levels of the uncarboxylated, inactive form of MGP (ucMGP) are associated with cardiovascular disease-related and all-cause mortality in human studies. However, the role of MGP in arterial stiffness is uncertain. Approach and Results: We examined the association of ucMGP levels with vascular calcification, arterial stiffness including carotid-femoral pulse wave velocity (PWV), and incident heart failure in community-dwelling adults from the Framingham Heart Study. To further investigate the link between MGP and arterial stiffness, we compared aortic PWV in age- and sex-matched young (4-month-old) and aged (10-month-old) wild-type and Mgp+/- mice. Among 7066 adults, we observed significant associations between higher levels of ucMGP and measures of arterial stiffness, including higher PWV and pulse pressure. Longitudinal analyses demonstrated an association between higher ucMGP levels and future increases in systolic blood pressure and incident HFpEF. Aortic PWV was increased in older, but not young, female Mgp+/- mice compared with wild-type mice, and this augmentation in PWV was associated with increased aortic elastin fiber fragmentation and collagen accumulation. CONCLUSIONS: This translational study demonstrates an association between ucMGP levels and arterial stiffness and future HFpEF in a large observational study, findings that are substantiated by experimental studies showing that mice with Mgp heterozygosity develop arterial stiffness. Taken together, these complementary study designs suggest a potential role of therapeutically targeting MGP in HFpEF.

Hepcidin Deficiency Protects Against Atherosclerosis.

Objective- Inflammatory stimuli enhance the progression of atherosclerotic disease. Inflammation also increases the expression of hepcidin, a hormonal regulator of iron homeostasis, which decreases intestinal iron absorption, reduces serum iron levels and traps iron within macrophages. The role of macrophage iron in the development of atherosclerosis remains incompletely understood. The objective of this study was to investigate the effects of hepcidin deficiency and decreased macrophage iron on the development of atherosclerosis. Approach and Results- Hepcidin- and LDL (low-density lipoprotein) receptor-deficient ( Hamp-/-/ Ldlr-/-) mice and Hamp+/+/ Ldlr-/- control mice were fed a high-fat diet for 21 weeks. Compared with control mice, Hamp-/-/ Ldlr-/- mice had decreased aortic macrophage activity and atherosclerosis. Because hepcidin deficiency is associated with both increased serum iron and decreased macrophage iron, the possibility that increased serum iron was responsible for decreased atherosclerosis in Hamp-/-/ Ldlr-/- mice was considered. Hamp+/+/ Ldlr-/- mice were treated with iron dextran so as to produce a 2-fold increase in serum iron. Increased serum iron did not decrease atherosclerosis in Hamp+/+/ Ldlr-/- mice. Aortic macrophages from Hamp-/-/ Ldlr-/- mice had less labile free iron and exhibited a reduced proinflammatory (M1) phenotype compared with macrophages from Hamp+/+/ Ldlr-/- mice. THP1 human macrophages treated with an iron chelator were used to model hepcidin deficiency in vitro. Treatment with an iron chelator reduced LPS (lipopolysaccharide)-induced M1 phenotypic expression and decreased uptake of oxidized LDL. Conclusions- In summary, in a hyperlipidemic mouse model, hepcidin deficiency was associated with decreased macrophage iron, a reduced aortic macrophage inflammatory phenotype and protection from atherosclerosis. The results indicate that decreasing hepcidin activity, with the resulting decrease in macrophage iron, may prove to be a novel strategy for the treatment of atherosclerosis.

Nationwide Analysis of Dog Bite Injuries: Different Age Groups, Different Injury Patterns.

BACKGROUND: As the number of households with dogs in the United States has increased, so has the incidence of dog bites. Contemporary analysis of nationwide epidemiological data regarding such injuries is scarce. The purpose of this study is to describe dog bite injury patterns and related surgical interventions with a focus on differences between pediatric and adult age groups. STUDY DESIGN: This is a retrospective study (2015-2017) using the National Trauma Data Bank. 10 569 patients were included. RESULTS: Of these, 4729 (44.7%) qualified as pediatric (age ≤ 12 years) and 5840 (55.3%) qualified as adults (age ≥ 13 years). Pediatric patients were more frequently admitted with facial injuries (78.1% vs. 29.3%, P < .01) and facial fractures (4.8% vs. 2.5%, P < .01), and had a higher incidence of facial bone surgical procedures (1.3% vs. .5%, P < .01). Adult patients were more frequently admitted with upper extremity injuries (65.8% vs. 21.2%, P < .01) and upper extremity vascular arterial injuries (2.3% vs. .2%, P < .01) with a higher incidence of upper extremity arterial procedures (1.3% vs. .2%, P < .01). CONCLUSION: This study demonstrates the contrast in injury patterns from dog bite between adults and children. These findings can dictate injury prevention policies and prepare clinicians to treat dog bite victims.

The Role of Bone Morphogenetic Protein Signaling in Non-Alcoholic Fatty Liver Disease.

Non-alcoholic fatty liver disease (NAFLD) affects over 30% of adults in the United States. Bone morphogenetic protein (BMP) signaling is known to contribute to hepatic fibrosis, but the role of BMP signaling in the development of NAFLD is unclear. In this study, treatment with either of two BMP inhibitors reduced hepatic triglyceride content in diabetic (db/db) mice. BMP inhibitor-induced decrease in hepatic triglyceride levels was associated with decreased mRNA encoding Dgat2, an enzyme integral to triglyceride synthesis. Treatment of hepatoma cells with BMP2 induced DGAT2 expression and activity via intracellular SMAD signaling. In humans we identified a rare missense single nucleotide polymorphism in the BMP type 1 receptor ALK6 (rs34970181;R371Q) associated with a 2.1-fold increase in the prevalence of NAFLD. In vitro analyses revealed R371Q:ALK6 is a previously unknown constitutively active receptor. These data show that BMP signaling is an important determinant of NAFLD in a murine model and is associated with NAFLD in humans.

HDAC9 is implicated in atherosclerotic aortic calcification and affects vascular smooth muscle cell phenotype.

Aortic calcification is an important independent predictor of future cardiovascular events. We performed a genome-wide association meta-analysis to determine SNPs associated with the extent of abdominal aortic calcification (n = 9,417) or descending thoracic aortic calcification (n = 8,422). Two genetic loci, HDAC9 and RAP1GAP, were associated with abdominal aortic calcification at a genome-wide level (P < 5.0 × 10-8). No SNPs were associated with thoracic aortic calcification at the genome-wide threshold. Increased expression of HDAC9 in human aortic smooth muscle cells promoted calcification and reduced contractility, while inhibition of HDAC9 in human aortic smooth muscle cells inhibited calcification and enhanced cell contractility. In matrix Gla protein-deficient mice, a model of human vascular calcification, mice lacking HDAC9 had a 40% reduction in aortic calcification and improved survival. This translational genomic study identifies the first genetic risk locus associated with calcification of the abdominal aorta and describes a previously unknown role for HDAC9 in the development of vascular calcification.