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Abstract Background Previous studies have shown that patients with hypercholesterolemia experience elevated levels of oxidized LDL (oxLDL), a molecule which triggers inflammation and collagenase activity. In this study we discovered novel mechanistic effects of oxLDL on tendon cells and the mediators regulating matrix remodeling by analyzing the expression and activity of related proteins and enzymes. These effects may contribute to tendon damage in patients with high cholesterol. Methods Isolated human tendon cells (male and female donors age 28 ± 1.4 age 37 ± 5.7, respectively) were incubated in the presence or absence of oxLDL. The influence of oxLDL on the expression level of key mRNA and proteins was examined using real time quantitative PCR, ELISA and Western blots. The activities of enzymes relevant to collagen synthesis and breakdown (lysyl oxidase and matrix metalloproteinases) were quantified using fluorometry. Finally, the isolated human tendon cells in a 3D construct were exposed to combinations of oxLDL and TGF-β to examine their interacting effects on collagen matrix remodeling. Results The one-way ANOVA of gene expression indicates that key mRNAs including TGFB, COL1A1, DCN, and LOX were significantly reduced in human tendon cells by oxLDL while MMPs were increased. The oxLDL reduced the activity of LOX at 50 µg/ml, whereas conversely MMP activities were induced at 25 µg/ml (P ≤ 0.01). COL1A1 synthesis and TGF-β secretion were also inhibited (P ≤ 0.05). Adding recombinant TGF-β reversed the effects of oxLDL on the expression of collagens and LOX. OxLDL also impaired collagen matrix remodeling (P ≤ 0.01), and adding TGF-β restored the native phenotype. Conclusion Exposure to oxLDL in patients with hypercholesterolemia may adversely affect the mechanical and structural properties of tendon tissue through a direct action of oxLDL on tendon cells, including impairment of TGF-β expression. This impairment leads to disturbed matrix remodeling and synthesis, thereby potentially leading to increased risk of acute or chronic tendon injury. Our discovery may provide an opportunity for developing effective treatments for tendon injury in hypercholesterolemia patients by targeting the TGF-β pathway.

Pneumatoceles are rare in neonates and most resolve spontaneously. However, pneumatoceles can persist and compromise cardiopulmonary function secondary to mass effect. Intervention aimed at decompressing the air cyst helps alleviate cardiopulmonary compression. We present the case of a 23 6/7 week gestation female infant born in the setting of severe maternal preeclampsia who developed respiratory failure associated with a pneumatocele that was successfully treated at the bedside with ultrasound-guided placement of a pigtail catheter. This novel intervention resulted in immediate decompression of the pneumatocele without recurrence which allowed stabilization of the patient for closure of a large patent ductus arteriosus (PDA) with subsequent improvement of her cardiopulmonary function and discharge home. Prior reports have shown successful percutaneous decompression using fluoroscopic guidance, in this report we show an ultrasound guided technique. This approach mitigates the distress associated with fluoroscopic-guided and operative interventions in these patients with compromised cardiopulmonary function. In addition, it eliminates the need for transportation in this fragile patient population.

Case of a male infant delivered at 36 weeks of gestational age and found to have a giant omphalocele, later complicated by intestinal perforation. A giant omphalocele is an omphalocele with an opening greater than 5 cm in diameter and containing the liver. It represents a therapeutic challenge secondary to viscero-abdominal disproportion, limiting the feasibility of a primary closure. Nowadays, the standard of care for giant omphaloceles is to adopt the “paint and wait” approach with delayed closure. Intestinal perforation is a rare complication of omphaloceles. Prior reports in the literature describe intestinal perforation in the setting of small to medium size omphalocele treated with operative exploratory laparotomy to address the intestinal perforation, followed by either primary or staged closure of the abdominal wall. We report the case of an infant with giant omphalocele who developed intestinal perforation at 4 weeks of life while undergoing “paint and wait”. He was managed non-operatively with peritoneal drains, antibiotics, and supportive care, while continuing with the “paint and wait” approach until he was optimized for operative repair of his giant omphalocele.

Congenital lung malformations (CLM) are most commonly determined to be congenital pulmonary airway malformations (CPAM) followed by bronchopulmonary sequestration (BPS) and hybrid CPAM/BPS lesions. Although prenatal diagnosis of intrathoracic CLMs is common, extrathoracic CLMs are rare with histopathologically confirmed diagnosis of simultaneous intrathoracic and extrathoracic CLMs not yet reported in literature. In the setting of both an intrathoracic and extrathoracic congenital lung lesion, currently no data exists addressing the timing as well as order in which the lesions should be resected. We present the case of a patient prenatally diagnosed with a left intralobar as well as a left infradiaphragmatic CLM, both confirmed on pathology as hybrid CPAM/BPS lesions. The lesions were resected in two separate minimally invasive operations, with resection of the intrathoracic lesion occurring at 4 months of age and the extrathoracic lesion following at 9 months. In the absence of symptoms, we suggest resection of intrathoracic lesions prior to extrathoracic lesions due to the increased risk of pulmonary infection.

Splenic rupture is a rare event in preterm and term infants. Symptoms of splenic rupture include acute blood loss, abdominal distention, and hypotension. We present the case of a 24 4/7 weeks gestation male infant born in the setting of preterm premature rupture of membranes who developed splenic rupture at 24 hours of life. Initially, the infant was managed medically. As the symptoms of abdominal compartment syndrome worsened, a bedside exploratory laparotomy was performed. The infant died on day of life 16 after developing hyperkalemia and pulmonary hemorrhage during an exchange transfusion for profound hyperbilirubinemia. This is the first report describing the management of splenic rupture in an extremely premature infant.

Extracorporeal membrane oxygenation (ECMO)-related hemolysis is a recognized complication and remains a source of significant morbidity and mortality in the neonatal population. This is the first description of continuous double-volume exchange transfusion (ET) performed for profound hemolysis that developed in a neonate with congenital heart disease on VA ECMO for sepsis. The aim of this report is to demonstrate the safety and efficacy of performing ET on a physiologically frail patient on ECMO support. Keywords: Veno-arterial extracorporeal membrane oxygenation, Hemolysis, Exchange transfusion

Background: Optimal timing for resection of asymptomatic congenital lung malformations (CLMs) remains controversial. The aim of this study is to define optimal timing for surgical intervention of patients with CLMs and define clinical variables that affect surgical outcomes.Methods: An IRB-approved retrospective analysis was conducted for patients undergoing surgery for CLMs between 2012 and 2017. Subjects were divided into cohorts based on timing of operative intervention. “Early intervention” was defined as surgery within 4 months of birth; “intermediate intervention”—between 4 and 6 months; and “late intervention”−6–12 months. Surgical outcomes including intraoperative estimated blood loss (EBL), surgical time, post-operative pneumothorax, length of time chest tube stayed in, and hospital length of stay were compared among the three groups using Fisher's exact test or Chi-squared test for categorical variables and one-way analysis of variance test for continuous variables.Results: We analyzed 63 patients who underwent surgery for CLM. There were no significant differences in baseline characteristics. Timing of surgery did not significantly correlate with post-operative outcomes. Specifically, there was no difference in operative time, EBL, post-operative pneumothorax, or length of hospital stay among the early, intermediate, and late intervention groups. Even after controlling for cyst-volume ratio (CVR), timing of surgery still did not affect post-operative outcomes.Conclusions: Surgical outcomes for resection of CLMs are not significantly affected by timing of surgery. We advocate for early intervention to decrease the incidence of associated complications that can occur with later intervention.

Background: In Peru, 11% of deaths are due to trauma. Iquitos is a large underserved Peruvian city isolated from central resources by its geography. Our objective was to implement a locally driven trauma registry to sustainably improve trauma healthcare in this region. Methods: All trauma patients presenting to the main regional referral hospital were included in the trauma registry. A pilot study retrospectively analyzed data from the first two months after implementation. Results: From March to April 2013, 572 trauma patients were entered into the database. Average age was 26.9 years. Ten percent of patients presented more than 24 hours after injury. Most common mechanisms of injury were falls (25.5%), motor vehicle collisions (23.3%), and blunt assault (10.5%). Interim analysis revealed that 99% of patients were entered into the database. However, documentation of vital signs was poor: 42% of patients had temperature, 26% had oxygen saturation documented. After reporting to registry staff, a significant increase in temperature (42 to 97%, P < 0.001) and oxygen saturation (26 to 92%, P < 0.001) documentation was observed. Conclusion: A trauma registry is possible to implement in a resource-poor setting. Future efforts will focus on analysis of data to enhance prevention and treatment of injuries in Iquitos.

Extracorporeal membrane oxygenation (ECMO) is a form of life support with an ever-expanding range of indications. Veno-venous (VV) ECMO is often utilized to support children with respiratory compromise, and has been employed successfully in the acute setting of traumatic tracheobronchial injury as well as during elective tracheal surgery. We present a successful case of VV ECMO used in the perioperative management of a tracheal repair for a traumatic laceration caused by attempts to retrieve an esophageal foreign body. While this mechanism of injury appears to be rare, we believe that VV-ECMO allowed for the optimal management of this child and should be considered for other extensive tracheal injuries in children.

We recently reported that oxidized LDL (oxLDL) induces an oscillatory increase in intracellular calcium ([Ca2+]i) levels in macrophages. Furthermore, we have shown that these [Ca2+]i oscillations mediate oxLDL's ability to inhibit macrophage apoptosis in response to growth factor deprivation. However, the signal transduction pathways by which oxLDL induces [Ca2+]i oscillations have not been elucidated. In this study, we show that these oscillations are mediated in part by intracellular mechanisms, as depleting extracellular Ca2+ did not completely abolish the effect. Inhibiting sarco-endoplasmic reticulum ATPase (SERCA) completely blocked [Ca2+]i oscillations, suggesting a role for Ca2+ reuptake by the ER. The addition of oxLDL resulted in an almost immediate activation of sphingosine kinase (SK), which can increase sphingosine-1-phosphate (S1P) levels by phosphorylating sphingosine. Moreover, S1P was shown to be as effective as oxLDL in blocking macrophage apoptosis and producing [Ca2+]i oscillations. This suggests that the mechanism in which oxLDL generates [Ca2+]i oscillations may be 1) activation of SK, 2) SK-mediated increase in S1P levels, 3) S1P-mediated Ca2+ release from intracellular stores, and 4) SERCA-mediated Ca2+ reuptake back into the ER.

Oxidized LDL (oxLDL) promotes lipid accumulation as well as growth and survival signaling in macrophages. OxLDL uptake is mainly due to scavenger receptors SR-AI/II and CD36. However, other scavenger receptors such as lectin-like oxLDL receptor-1 (LOX-1) may also play a role. We used mice with targeted inactivation of the LOX-1 gene to define the role of this receptor in the uptake of oxLDL and in activation of survival pathways. There was no difference in uptake or degradation of 125I-oxLDL in unstimulated macrophages from wild-type and LOX-1 knockout mice and no difference in the rate of clearance of oxLDL from plasma in vivo. However, when expression of LOX-1 was induced with lysophosphatidylcholine, oxLDL uptake and degradation increased 2-fold in wild-type macrophages but did not change in LOX-1 knockout macrophages. Macrophages lacking LOX-1 showed the same stimulation of PKB phosphorylation and enhancement of survival by oxLDL as wild-type cells. These data show that LOX-1 does not alter the uptake of oxLDL in unstimulated macrophages and is not essential for the pro-survival effect of oxLDL in these cells. However, LOX-1 expression is highly inducible by lysophosphatidylcholine and pro-inflammatory cytokines, and if that occurred in macrophages within atheromas, LOX-1 could substantially increase oxLDL uptake by lesion macrophages.

Oxidized LDL (oxLDL) is known to induce endothelial adhesion molecule and monocyte chemoattractant protein 1 expression and this is thought to be involved in monocyte recruitment into atherosclerotic lesions. oxLDL has also been found to induce macrophage proliferation. The purpose of the present study was to determine whether oxLDL might also have the ability to increase macrophage populations by inhibiting apoptosis. We found that oxLDL caused a dose-dependent inhibition of the apoptosis that occurs in cultured bone marrow-derived macrophages after macrophage colony-stimulating factor (M-CSF) withdrawal without inducing proliferation. Incubation of macrophages with either native LDL or acetylated LDL had no effect on apoptosis. The prosurvival effect of oxLDL was not inhibited by neutralizing antibodies to granulocyte-macrophage colony-stimulating factor, was maintained in mice homozygous for a mutation in the M-CSF gene, and was not due to other secreted cytokines or growth factors. oxLDL caused activation of the mitogen-activated protein kinases ERK1/2 (extracellular signal-regulated kinases 1 and 2) as well as protein kinase B (PKB), a target of phosphatidylinositol 3-kinase (PI 3-kinase). Furthermore, there was phosphorylation of two important prosurvival PKB targets, I-κBα(Ser-32) and Bad(Ser-136). The MEK inhibitors PD 98059 and U0126 blocked ERK1/2 activation but did not diminish survival. Conversely, the PI 3-kinase inhibitors LY 294002 and wortmannin blocked PKB activation, and the ability of oxidized LDL to promote macrophage survival. Taken together, these results indicate that oxLDL can directly activate a PI 3-kinase/PKB-dependent pathway that permits macrophage survival in the absence of growth factors. —Hundal, R. S., B. S. Salh, J. W. Schrader, A. Gómez-Muñoz, V. Duronio, and U. P. Steinbrecher. Oxidized low density lipoprotein inhibits macrophage apoptosis through activation of the PI 3-kinase/PKB pathway.

Angiogenesis is associated with the tissue changes underlying chronic overuse tendinopathy. We hypothesized that repetitive, cyclic loading of human tendon cells would lead to increased expression and activity of angiogenic factors. We subjected isolated human tendon cells to overuse tensile loading using an in vitro model (1 Hz, 10% equibiaxial strain). We found that mechanically stimulated human tendon cells released factors that promoted in vitro proliferation and tube formation by human umbilical vein endothelial cells (HUVEC). In response to cyclic strain, there was a transient increase in the expression of several angiogenic genes including ANGPTL4, FGF-2, COX-2, SPHK1, TGF-alpha, VEGF-A and VEGF-C, with no change in anti-angiogenic genes (BAI1, SERPINF1, THBS1 and 2, TIMP1-3). Cyclic strain also resulted in the extracellular release of ANGPTL4 protein by tendon cells. Our study is the first report demonstrating the induction of ANGPTL4 mRNA and release of ANGPTL4 protein in response to cyclic strain. Tenocytes may contribute to the upregulation of angiogenesis during the development of overuse tendinopathy.