James G. Taylor Vi

Identification of FGFR4-activating mutations in human rhabdomyosarcomas that promote metastasis in xenotransplanted models

Rhabdomyosarcoma (RMS) is a childhood cancer originating from skeletal muscle, and patient survival is poor in the presence of metastatic disease. Few determinants that regulate metastasis development have been identified. The receptor tyrosine kinase FGFR4 is highly expressed in RMS tissue, suggesting a role in tumorigenesis, although its functional importance has not been defined. Here, we report the identification of mutations in FGFR4 in human RMS tumors that lead to its activation and present evidence that it functions as an oncogene in RMS. Higher FGFR4 expression in RMS tumors was associated with advanced-stage cancer and poor survival, while FGFR4 knockdown in a human RMS cell line reduced tumor growth and experimental lung metastases when the cells were transplanted into mice. Moreover, 6 FGFR4 tyrosine kinase domain mutations were found among 7 of 94 (7.5%) primary human RMS tumors. The mutants K535 and E550 increased autophosphorylation, Stat3 signaling, tumor proliferation, and metastatic potential when expressed in a murine RMS cell line. These mutants also transformed NIH 3T3 cells and led to an enhanced metastatic phenotype. Finally, murine RMS cell lines expressing the K535 and E550 FGFR4 mutants were substantially more susceptible to apoptosis in the presence of a pharmacologic FGFR inhibitor than the control cell lines expressing the empty vector or wild-type FGFR4. Together, our results demonstrate that mutationally activated FGFR4 acts as an oncogene, and these are what we believe to be the first known mutations in a receptor tyrosine kinase in RMS. These findings support the potential therapeutic targeting of FGFR4 in RMS.

Epidermal devices for noninvasive, precise, and continuous mapping of macrovascular and microvascular blood flow

Advances in ultrathin, skin-like electronics lead to wearable devices for continuous, noninvasive blood flow monitoring. Continuous monitoring of variations in blood flow is vital in assessing the status of microvascular and macrovascular beds for a wide range of clinical and research scenarios. Although a variety of techniques exist, most require complete immobilization of the subject, thereby limiting their utility to hospital or clinical settings. Those that can be rendered in wearable formats suffer from limited accuracy, motion artifacts, and other shortcomings that follow from an inability to achieve intimate, noninvasive mechanical linkage of sensors with the surface of the skin. We introduce an ultrathin, soft, skin-conforming sensor technology that offers advanced capabilities in continuous and precise blood flow mapping. Systematic work establishes a set of experimental procedures and theoretical models for quantitative measurements and guidelines in design and operation. Experimental studies on human subjects, including validation with measurements performed using state-of-the-art clinical techniques, demonstrate sensitive and accurate assessment of both macrovascular and microvascular flow under a range of physiological conditions. Refined operational modes eliminate long-term drifts and reduce power consumption, thereby providing steps toward the use of this technology for continuous monitoring during daily activities.

Hemodynamic Predictors of Mortality in Adults with Sickle Cell Disease

BACKGROUND Pulmonary hypertension (PH) in adults with sickle cell disease (SCD) is associated with early mortality, but no prior studies have evaluated quantitative relationships of mortality to physiological measures of pre- and postcapillary PH. OBJECTIVES To identify risk factors associated with mortality and to estimate the expected survival in a cohort of patients with SCD with PH documented by right heart catheterization. METHODS Nine-year follow-up data (median, 4.7 yr) from the National Institutes of Health SCD PH screening study are reported. A total of 529 adults with SCD were screened by echocardiography between 2001 and 2010 with no exclusion criteria. Hemodynamic data were collected from 84 patients. PH was defined as mean pulmonary artery pressure (PAP) ≥ 25 mm Hg. Survival rates were estimated by the Kaplan-Meier method, and mortality risk factors were analyzed by the Cox proportional hazards regression. MEASUREMENTS AND MAIN RESULTS Specific hemodynamic variables were independently related to mortality: mean PAP (hazard ratio [HR], 1.61; 95% confidence interval [CI], 1.05-2.45 per 10 mm Hg increase; P = 0.027), diastolic PAP (HR, 1.83; 95% CI, 1.09-3.08 per 10 mm Hg increase; P = 0.022), diastolic PAP - pulmonary capillary wedge pressure (HR, 2.19; 95% CI, 1.23-3.89 per 10 mm Hg increase; P = 0.008), transpulmonary gradient (HR, 1.78; 95% CI, 1.14-2.79 per 10 mm Hg increase; P = 0.011), and pulmonary vascular resistance (HR, 1.44; 95% CI, 1.09-1.89 per Wood unit increase; P = 0.009) as risk factors for mortality. CONCLUSIONS Mortality in adults with SCD and PH is proportional to the physiological severity of precapillary PH, demonstrating its prognostic and clinical relevance despite anemia-induced high cardiac output and less severely elevated pulmonary vascular resistance.

Severe painful vaso-occlusive crises and mortality in a contemporary adult sickle cell anemia cohort study.

Background Frequent painful vaso-occlusive crises (VOCs) were associated with mortality in the Cooperative Study of Sickle Cell Disease (CSSCD) over twenty years ago. Modern therapies for sickle cell anemia (SCA) like hydroxyurea are believed to have improved overall patient survival. The current study sought to determine the relevance of the association between more frequent VOCs and death and its relative impact upon overall mortality compared to other known risk factors in a contemporary adult SCA cohort. Methods Two hundred sixty four SCA adults were assigned into two groups based on patient reported outcomes for emergency department (ED) visits or hospitalizations for painful VOC treatment during the 12 months prior to evaluation. Results Higher baseline hematocrit (p = 0.0008), ferritin (p = 0.005), and HDL cholesterol (p = 0.01) were independently associated with 1 or more painful VOCs requiring an ED visit or hospitalization for acute pain. During a median follow-up of 5 years, mortality was higher in the ED visit/hospitalization group (relative risk [RR] 2.68, 95% CI 1.1-6.5, p = 0.03). Higher tricuspid regurgitatant jet velocity (TRV) (RR 2.41, 95% CI 1.5-3.9, p < 0.0001), elevated ferritin (RR 4.00, 95% CI 1.8-9.0, p = 0.001) and lower glomerular filtration rate (RR=2.73, 95% CI 1.6-4.6, p < 0.0001) were also independent risk factors for mortality. Conclusions Severe painful VOCs remain a marker for SCA disease severity and premature mortality in a modern cohort along with other known risk factors for death including high TRV, high ferritin and lower renal function. The number of patient reported pain crises requiring healthcare utilization is an easily obtained outcome that could help to identify high risk patients for disease modifying therapies. Trial Registration ClinicalTrials.gov NCT00011648 http://clinicaltrials.gov/

Laboratory and echocardiography markers in sickle cell patients with leg ulcers

In this prospective cohort of adults with SCD, we confirm that leg ulcers are still frequent and are associated with elevated TRVand markers of hemolysis. We describe a novel association of leg ulcer with hyperuricemia and oxygen desaturation and suggest potential implications for uric acid as a marker of vascular dysfunction.

Frequency of Hospitalizations for Pain and Association With Altered Brain Network Connectivity in Sickle Cell Disease

UNLABELLED Sickle cell disease (SCD) is a hemoglobinopathy that affects more than 100,000 individuals in the United States. The disease is characterized by the presence of sickle hemoglobin and recurrent episodes of pain. Some individuals with SCD experience frequent hospitalizations and a high burden of pain. The role of central mechanisms in SCD pain has not been explored. Twenty-five adolescents and young adults with SCD underwent functional magnetic resonance imaging. Participants were stratified into groups with high pain or low pain based on the number of hospitalizations for pain in the preceding 12 months. Resting state functional connectivity was analyzed using seed-based and dual regression independent component analysis. Intrinsic brain connectivity was compared between the high pain and low pain groups, and association with fetal hemoglobin, a known modifier of SCD, was explored. Patients in the high pain group displayed an excess of pronociceptive connectivity such as between anterior cingulate and default mode network structures, such as the precuneus, whereas patients in the low pain group showed more connectivity to antinociceptive structures such as the perigenual and subgenual cingulate. Although a similar proportion of patients in both groups reported that they were on hydroxyurea, the fetal hemoglobin levels were significantly higher in the low pain group and were associated with greater connectivity to antinociceptive structures. These findings support the role of central mechanisms in SCD pain. Intrinsic brain connectivity should be explored as a complementary and objective outcome measure in SCD pain research. PERSPECTIVE Altered connectivity patterns associated with high pain experience in patients with sickle cell disease suggest a possible role of central mechanisms in sickle cell pain. Resting state brain connectivity studies should be explored as an effective methodology to investigate pain in SCD.