Staphylococcus aureus alpha toxin activates Notch in vascular cells.

Staphylococcus aureus infection is one of the leading causes of morbidity in hospitalized patients in the United States, an effect compounded by increasing antibiotic resistance. The secreted agent hemolysin alpha toxin (Hla) requires the receptor A Disintegrin And Metalloproteinase domain-containing protein 10 (ADAM10) to mediate its toxic effects. We hypothesized that these effects are in part regulated by Notch signaling, for which ADAM10 activation is essential. Notch proteins function in developmental and pathological angiogenesis via the modulation of key pathways in endothelial and perivascular cells. Thus, we hypothesized that Hla would activate Notch in vascular cells. Human umbilical vein endothelial cells were treated with recombinant Hla (rHla), Hla-H35L (genetically inactivated Hla), or Hank's solution (HBSS), and probed by different methods. Luciferase assays showed that Hla (0.01 µg/mL) increased Notch activation by 1.75 ± 0.5-fold as compared to HBSS controls (p < 0.05), whereas Hla-H35L had no effect. Immunocytochemistry and Western blotting confirmed these findings and revealed that ADAM10 and γ-secretase are required for Notch activation after inhibitor and siRNA assays. Retinal EC in mice engineered to express yellow fluorescent protein (YFP) upon Notch activation demonstrated significantly greater YFP intensity after Hla injection than controls. Aortic rings from Notch reporter mice embedded in matrix and incubated with rHla or Hla-H35L demonstrate increased Notch activation occurs at tip cells during sprouting. These mice also had higher skin YFP intensity and area of expression after subcutaneous inoculation of S. aureus expressing Hla than a strain lacking Hla in both EC and pericytes assessed by microscopy. Human liver displayed strikingly higher Notch expression in EC and pericytes during S. aureus infection by immunohistochemistry than tissues from uninfected patients. In sum, our results demonstrate that the S. aureus toxin Hla can potently activate Notch in vascular cells, an effect which may contribute to the pathobiology of infection with this microorganism.

Pediatric lymphatic malformations: evolving understanding and therapeutic options.

Multimodal treatment of lymphatic malformations continues to expand as new information about the biology and genetics of these lesions is discovered, along with knowledge gained from clinical practice. A patient-centered approach, ideally provided by a multidisciplinary medical and surgical team, should guide timing and modality of treatment. Current treatment options include observation, surgery, sclerotherapy, radiofrequency ablation, and laser therapy. New medical and surgical therapies are emerging, and include sildenafil, propranolol, sirolimus, and vascularized lymph node transfer. The primary focus of management is to support and optimize these patients' quality of life. Researchers continue to study lymphatic malformations with the goal of increasing therapeutic options and developing effective clinical pathways for these complicated lesions.

Management of lymphatic malformations in children.

PURPOSE OF REVIEW: To review the literature on lymphatic malformations and to provide current opinion about the management of these lesions. RECENT FINDINGS: Current treatment options include nonoperative management, surgery, sclerotherapy, radiofrequency ablation, and laser therapy. New therapies are emerging, including sildenafil, propranolol, sirolimus, and vascularized lymph node transfer. The primary focus of management centers on the patient's quality of life. SUMMARY: Multimodal treatment of lymphatic malformations continues to expand as new information about the biology and genetics of these lesions is discovered, in addition to knowledge gained from clinical practice. A patient-centered approach should guide timing and modality of treatment. Continued study of lymphatic malformations will increase and solidify a treatment algorithm for these complicated lesions.

Optimal Management of the Hyperkinetic Gallbladder: A Comparison of Outcomes Between Operative and Nonoperative Approaches.

BACKGROUND: A hyperkinetic gallbladder is defined as a hepatobiliary iminodiacetic acid (HIDA) scan ejection fraction (EF) of >80%. This condition is poorly described, and there is no current consensus on optimal management. The intent of this study was to determine if cholecystectomy improves symptoms in patients with a hyperkinetic gallbladder when compared to those managed nonoperatively and if there were variables predictive of symptom improvement with or without cholecystectomy. MATERIALS AND METHODS: This retrospective study included patients from 3 academic hospitals in the Atlanta metro area between the years 2006 and 2018. All patients with an EF >80% were included. Following voluntary exclusion patients were contacted by phone. Each patient was administered a questionnaire regarding their surgical history, medical management, and current symptom profile via Otago score. Institutional Institutional Review Board approval was obtained. RESULTS: 4785 HIDA scans were performed, and 194 reported an EF >80% (incidence 15.7%). 96% of these scans were reported as normal by the radiologist. 68 patients were able to be contacted by phone and completed the questionnaire. 18 patients underwent cholecystectomy, and 89% reported that their symptoms attributed to gallbladder disease were no longer present. 50 patients did not undergo cholecystectomy, and alternate diagnoses, medication prescriptions, diet modification, emergency department visits, and Otago score were higher in this cohort. DISCUSSION: Patients who undergo cholecystectomy for a diagnosis of hyperkinetic gallbladder, on average, report improvement in symptoms when compared to patients managed nonoperatively. This study supports the practice of reporting and managing hyperkinetic gallbladders as a pathologic entity.

Role of Negative Pressure Wound Therapy When Performing Elective Open Colectomy.

Background: The impact of negative pressure wound therapy (NPWT) as an adjunct to colorectal surgery is largely unknown. The purpose of this study was to determine whether NPWT impacts wound complications during elective open colectomy. Methods: The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) and colectomy targeted procedure databases were queried from 2012-2018 for patients undergoing non-emergent planned open colectomies. Groups were propensity score matched for anastomosis type (ileo-colic, colo-colic, colo-rectal), age, body mass index (BMI), diabetes, smoking, steroid use, wound classification, American Society of Anesthesiologists (ASA) class, operative time, and wound layers closed. Wound complications were defined as superficial surgical site infection (SSI), deep incisional SSI, and dehiscence. Results: A total of 15,770 patients were identified; 92 underwent simultaneous NPWT (0.58%). Non-NPWT patients were matched at a 5:1 ratio, producing 460 comparisons. There was no difference in wound complications (8.26% non-NPWT vs. 6.52% NPWT; p = 0.574). In addition, there were no differences in wound complications when only including patients who had NPWT placed over closed skin (9.11% non-NPWT vs. 7.25% NPWT; p = 0.789). On multivariable analysis, NPWT was not associated with wound complications (odds ratio [OR] 0.79; 95% confidence interval [CI], 0.37-1.69). Conclusions: Negative pressure wound therapy does not reduce wound complications in open elective colectomies. Large randomized studies and more granular data are needed to ascertain if there is any benefit in select patient populations.

Perfusion-guided sonopermeation of neuroblastoma: a novel strategy for monitoring and predicting liposomal doxorubicin uptake in vivo.

Neuroblastoma (NB) is the most common extracranial solid tumor in infants and children, and imposes significant morbidity and mortality in this population. The aggressive chemoradiotherapy required to treat high-risk NB results in survival of less than 50%, yet is associated with significant long-term adverse effects in survivors. Boosting efficacy and reducing morbidity are therefore key goals of treatment for affected children. We hypothesize that these may be achieved by developing strategies that both focus and limit toxic therapies to the region of the tumor. One such strategy is the use of targeted image-guided drug delivery (IGDD), which is growing in popularity in personalized therapy to simultaneously improve on-target drug deposition and assess drug pharmacodynamics in individual patients. IGDD strategies can utilize a variety of imaging modalities and methods of actively targeting pharmaceutical drugs, however in vivo imaging in combination with focused ultrasound is one of the most promising approaches already being deployed for clinical applications. Over the last two decades, IGDD using focused ultrasound with "microbubble" ultrasound contrast agents (UCAs) has been increasingly explored as a method of targeting a wide variety of diseases, including cancer. This technique, known as sonopermeation, mechanically augments vascular permeability, enabling increased penetration of drugs into target tissue. However, to date, methods of monitoring the vascular bioeffects of sonopermeation in vivo are lacking. UCAs are excellent vascular probes in contrast-enhanced ultrasound (CEUS) imaging, and are thus uniquely suited for monitoring the effects of sonopermeation in tumors. Methods: To monitor the therapeutic efficacy of sonopermeation in vivo, we developed a novel system using 2D and 3D quantitative contrast-enhanced ultrasound imaging (qCEUS). 3D tumor volume and contrast enhancement was used to evaluate changes in blood volume during sonopermeation. 2D qCEUS-derived time-intensity curves (TICs) were used to assess reperfusion rates following sonopermeation therapy. Intratumoral doxorubicin (and liposome) uptake in NB was evalauted ex vivo along with associated vascular changes. Results: In this study, we demonstrate that combining focused ultrasound therapy with UCAs can significantly enhance chemotherapeutic payload to NB in an orthotopic xenograft model, by improving delivery and tumoral uptake of long-circulating liposomal doxorubicin (L-DOX) nanoparticles. qCEUS imaging suggests that changes in flow rates are highly sensitive to sonopermeation and could be used to monitor the efficacy of treatment in vivo. Additionally, initial tumor perfusion may be a good predictor of drug uptake during sonopermeation. Following sonopermeation treatment, vascular biomarkers show increased permeability due to reduced pericyte coverage and rapid onset of doxorubicin-induced apoptosis of NB cells but without damage to blood vessels. Conclusion: Our results suggest that significant L-DOX uptake can occur by increasing tumor vascular permeability with microbubble sonopermeation without otherwise damaging the vasculature, as confirmed by in vivo qCEUS imaging and ex vivo analysis. The use of qCEUS imaging to monitor sonopermeation efficiency and predict drug uptake could potentially provide real-time feedback to clinicians for determining treatment efficacy in tumors, leading to better and more efficient personalized therapies. Finally, we demonstrate how the IGDD strategy outlined in this study could be implemented in human patients using a single case study.