Lineage-Specific Wnt Reporter Elucidates Mesenchymal Wnt Signaling during Bone Repair.

ß-Catenin-dependent Wnt signaling controls numerous aspects of skeletal development and postnatal bone repair. Currently available transgenic Wnt reporter mice allow for visualization of global canonical Wnt signaling activity within skeletal tissues, without delineation of cell type. This is particularly important in a bone repair context, in which the inflammatory phase can obscure the visualization of mesenchymal cell types of interest. To tackle the issue of tissue-specific Wnt signaling, we have generated and characterized a transgenic mouse strain [termed paired related homeobox 1 (Prx1)-Wnt-green fluorescent protein (GFP), by crossing a previously validated Prx1-Cre strain with a nuclear fluorescent reporter driven by T-cell factor/lymphoid enhancer factor activity (Rosa26-Tcf/Lef-LSL-H2B-GFP)]. Prx1-Wnt-GFP animals were subject to three models of long bone and membranous bone repair (displaced forelimb fracture, tibial cortical defect, and frontal bone defect). Results showed that, irrespective of bone type, locoregional mesenchymal cell activation of Wnt signaling occurs in a defined temporospatial pattern among Prx1-Wnt-GFP mice. In summary, Prx1-Wnt-GFP reporter animals allow for improved visualization, spatial discrimination, and facile quantification of Wnt-activated mesenchymal cells within models of adult bone repair.

Pericytes in Sarcomas and Other Mesenchymal Tumors.

Tumors of mesenchymal origin are a diverse group, with >130 distinct entities currently recognized by the World Health Organization. A subset of mesenchymal tumors grow or invade in a perivascular fashion, and their potential relationship to pericytes is a matter of ongoing interest. In fact, multiple intersections exist between pericytes and tumors of mesenchymal origin. First, pericytes are the likely cell of origin for a group of mesenchymal tumors with a common perivascular growth pattern. These primarily benign tumors grow in a perivascular fashion and diffusely express canonical pericyte markers such as CD146, smooth muscle actin (SMA), platelet-derived growth factor receptor beta (PDGFR-ß), and RGS5. These benign tumors include glomus tumor, myopericytoma, angioleiomyoma, and myofibroma. Second and as suggested by animal models, pericytes may give rise to malignant sarcomas. This is not a suggestion that all sarcomas within a certain subtype arise from pericytes, but that genetic modifications within a pericyte cell type may give rise to sarcomas. Third, mesenchymal tumors that are likely not a pericyte derivative co-opt pericyte markers in certain contexts. These include the PEComa family of tumors and liposarcoma. Fourth and finally, as "guardians" that enwrap the microvasculature, nonneoplastic pericytes may be important in sarcoma disease progression.

Leveraging Behavioral Economics to Improve Heart Failure Care and Outcomes.

Behavioral challenges are often present in human illness, so behavioral economics is increasingly being applied in healthcare settings to better understand why patients choose healthy or unhealthy behaviors. The application of behavioral economics to healthcare settings parallels recent shifts in policy and reimbursement structures that hold providers accountable for outcomes that are dependent on patient behaviors. Numerous studies have examined the application of behavioral economics principles to policy making and health behaviors, but there are limited data on applying these concepts to the management of chronic conditions, such as heart failure (HF). Given its increasing prevalence and high associated cost of care, HF is a paradigm case for studying novel approaches to improve health care; therefore, if we can better understand why patients with HF make the choices they do, then we may be more poised to help them manage their medications, influence daily behaviors, and encourage healthy decision making. In this article, we will give a brief explanation of the core behavioral economics concepts that apply to patients with HF. We will also examine how to craft these concepts into tools such as financial incentives and social networks that may improve the management of patients with HF. We believe that behavioral economics can help us understand barriers to change, encourage positive behaviors, and offer additional approaches to improving the outcomes of patients with HF.

Pericytes for Therapeutic Bone Repair.

Besides seminal functions in angiogenesis and blood pressure regulation, microvascular pericytes possess a latent tissue regenerative potential that can be revealed in culture following transition into mesenchymal stem cells. Endowed with robust osteogenic potential, pericytes and other related perivascular cells extracted from adipose tissue represent a potent and abundant cell source for refined bone tissue engineering and improved cell therapies of fractures and other bone defects. The use of diverse bone formation assays in vivo, which include mouse muscle pocket osteogenesis and calvaria replenishment, rat and dog spine fusion, and rat non-union fracture healing, has confirmed the superiority of purified perivascular cells for skeletal (re)generation. As a surprising observation though, despite strong endogenous bone-forming potential, perivascular cells drive bone regeneration essentially indirectly, via recruitment by secreted factors of local osteo-progenitors.

Anti-microRNA-378a enhances wound healing process by upregulating integrin beta-3 and vimentin.

Delayed or impaired wound healing is a major public health issue worldwide, especially in patients with diabetes mellitus and vascular atherosclerosis. MicroRNAs have been identified as key regulators of wound healing. Here, we show that miR-Pirate378a transgenic mice (and thus have inhibited miR-378a-5p function) display enhanced wound healing. Expression of vimentin and ß3 integrin, two important modulators of wound healing, is markedly elevated in the transgenic mice. MiR-Pirate378a-transfected cells display greater mobility during migration assays, which was hypothesized to be due to the upregulation of vimentin and ß3 integrin. Both molecules were confirmed to be targets of miR-378a, and thus their expression could be rescued by miR-Pirate378a. Overexpression of vimentin also contributed to fibroblast differentiation, and upregulation of ß3 integrin was responsible for increased angiogenesis. Mice treatment with miR-Pirate378a-conjugated nanoparticles displayed enhanced wound healing. Thus, we have demonstrated that knockdown of miR-378a increased the expression of its target proteins, vimentin, and ß3 integrin, which accelerated fibroblast migration and differentiation in vitro and enhanced wound healing in vivo.

Impact of Consolidative Radiation on Overall and Progression-Free Survival in Pediatric, Adolescent, and Young Adult Metastatic Bone and Soft Tissue Sarcoma.

PURPOSE: To determine the association between consolidative radiation (RT) and survival in children, adolescents, and young adults with metastatic sarcoma. METHODS AND MATERIALS: Eligibility criteria included patients aged ≤39 years with newly diagnosed metastatic bone or soft tissue sarcoma who completed local control of the primary tumor without disease progression. Consolidative RT was defined as RT to all known sites of metastatic disease. The Kaplan-Meier method was used to estimate overall survival (OS) and progression-free survival (PFS). The least absolute shrinkage and selection operator Cox provided adjusted estimates. To account for immortal time bias, consolidative RT was used as a time-varying covariate in a time dependent Cox model. Distant failure was estimated using the Fine-Gray model. RESULTS: Patients (n = 85) had a median age at diagnosis of 14.8 years. Most common histology was Ewing Sarcoma (45.9%) followed by rhabdomyosarcoma (40.0%). Receipt of consolidative RT was associated with Ewing Sarcoma (P < .001) and local control modality as those who underwent local control with surgery and RT compared with surgery alone were more likely to be treated with consolidative RT (P = .034). Consolidative RT was independently associated with improved OS (hazard ratio [HR], 0.41; 95% CI, 0.17-0.98; P = .045) and improved PFS (HR, 0.37; 95% CI, 0.16-0.88; P = .024) after adjusting for confounding variables and immortal time bias. Patients treated with consolidative RT also experienced a lower risk of distant failure (HR, 0.33; 95% CI, 0.17-0.64; P = .001). In an independent data set of patients with metachronous progression (n = 36), consolidative RT remained independently associated with improved OS. CONCLUSIONS: Consolidative RT was independently associated with improved OS and PFS and decreased risk of distant failure in child, adolescent, and young adult patients with metastatic sarcoma. Future work should evaluate biomarkers to optimize patient selection, timing, and dose for consolidative RT.

TrkA + sensory neurons regulate osteosarcoma proliferation and vascularization to promote disease progression.

Bone pain is a presenting feature of bone cancers such as osteosarcoma (OS), relayed by skeletal-innervating peripheral afferent neurons. Potential functions of tumor-associated sensory neurons in bone cancers beyond pain sensation are unknown. To uncover neural regulatory functions, a chemical-genetic approach in mice with a knock-in allele for TrkA was used to functionally perturb sensory nerve innervation during OS growth and disease progression. TrkA inhibition in transgenic mice led to significant reductions in sarcoma-associated sensory innervation and vascularization, tumor growth and metastasis, and prolonged overall survival. Single-cell transcriptomics revealed that sarcoma denervation was associated with phenotypic alterations in both OS tumor cells and cells within the tumor microenvironment, and with reduced calcitonin gene-related peptide (CGRP) and vascular endothelial growth factor (VEGF) signaling. Multimodal and multi-omics analyses of human OS bone samples and human dorsal root ganglia neurons further implicated peripheral innervation and neurotrophin signaling in OS tumor biology. In order to curb tumor-associated axonal ingrowth, we next leveraged FDA-approved bupivacaine liposomes leading to significant reductions in sarcoma growth, vascularity, as well as alleviation of pain. In sum, TrkA-expressing peripheral neurons positively regulate key aspects of OS progression and sensory neural inhibition appears to disrupt calcitonin receptor signaling (CALCR) and VEGF signaling within the sarcoma microenvironment leading to significantly reduced tumor growth and improved survival. These data suggest that interventions to prevent pathological innervation of osteosarcoma represent a novel adjunctive therapy to improve clinical outcomes and survival.

Daily Head and Neck Treatment Assessment for Optimal Proton Therapy Planning Robustness.

Robust optimization in proton therapy ensures adequate target coverage; however, validation of fractional plan quality and setup uncertainty in patients has not been performed. We aimed to assess plan robustness on delivered head and neck proton plans classified into two categories: (1) primary only (PO) and (2) primary and neck nodal (PNN) coverage. Registration at the machine was utilized for daily CBCT to generate a synthetic CT. The dose for the clinical target volume (CTV) and organs at risk (OAR) was compared to the expected robustness bands using 3.5% range uncertainty and 3 mm vs. 5 mm setup uncertainty. The fractional deviation was defined as D95% and V100% outside of uncertainty constraints. About 203 daily fractions from 6 patients were included for analysis. The percentage of fractions that exceeded robustness calculations was greater in 3 mm as compared to 5 mm setup uncertainty for both CTV and OAR volumes. PO plans had clinically insignificant average fractional deviation, less than 1%, in delivered D95% and V100%. In comparison, PNN plans had up to 2.2% average fractional deviation in delivered V100% using 3 mm robustness. Given the need to balance dose accuracy with OAR sparing, we recommend the utilization of 3 mm setup uncertainty as an acceptable simulation of the dose delivered.

Impact of socioeconomic status and chemotherapy on neurocognitive performance in children with brain tumors.

Background: Although the relationship between radiation and neurocognition has been extensively studied in the pediatric brain tumor population, it is increasingly recognized that neurocognitive impairment is multifactorial. Therefore, we quantified the effect of socioeconomic status (SES) and chemotherapy on neurocognitive impairment and decline post-treatment. Methods: Eligible patients included those diagnosed with a brain tumor at < 22 years of age with ≥1 neurocognitive assessment. Neurocognitive impairment was defined as performance 1.5 standard deviations below the normative mean using age-standardized measures of intellectual function. Neurocognitive decline was defined as a negative slope. Neurocognitive outcomes included Wechsler indices of Full-Scale Intelligence Quotient (IQ). Logistic regression identified variables associated with neurocognitive impairment. Longitudinal data was analyzed using linear mixed models. Results: Eligible patients (n = 152, median age at diagnosis = 9.6 years) had a mean neurocognitive follow-up of 50.2 months. After accounting for age and receipt of craniospinal irradiation, patients with public insurance had 8-fold increased odds of impaired IQ compared to private insurance (odds ratio [OR]: 7.59, P < .001). After accounting for age, change in IQ was associated with chemotherapy use (slope: -0.45 points/year with chemotherapy vs. 0.71 points/year without chemotherapy, P = .012). Conclusions: Public insurance, an indicator of low SES, was associated with post-treatment impairment in IQ, highlighting the need to incorporate SES measures into prospective studies. Chemotherapy was associated with change in IQ. Further work is needed to determine whether impairment associated with low SES is secondary to baseline differences in IQ prior to brain tumor diagnosis, brain tumor/therapy itself, or some combination thereof.

Improving Quality Metrics in Radiation Oncology: Implementation of Pretreatment Peer Review for Stereotactic Body Radiation Therapy in Patients with Thoracic Cancer.

Purpose: Traditional peer reviews occur weekly, and can take place up to 1 week after the start of treatment. The American Society for Radiation Oncology peer-review white paper identified stereotactic body radiation therapy (SBRT) as a high priority for contour/plan review before the start of treatment, considering both the rapid-dose falloff and short treatment course. Yet, peer-review goals for SBRT must also balance physician time demands and the desire to avoid routine treatment delays that would occur in the setting of a 100% pretreatment (pre-Tx) review compliance requirement or prolonging the standard treatment planning timeline. Herein, we report on our pilot experience of a pre-Tx peer review of thoracic SBRT cases. Methods and Materials: From March 2020 to August 2021, patients undergoing thoracic SBRT were identified for pre-Tx review, and placed on a quality checklist. We implemented twice-weekly meetings for detailed pre-Tx review of organ-at-risk/target contours and dose constraints in the treatment planning system for SBRT cases. Our quality metric goal was to peer review ≥90% of SBRT cases before exceeding 25% of the dose delivered. We used a statistical process control chart with sigma limits (ie, standard deviations [SDs]) to access compliance rates with pre-Tx review implementation. Results: We identified 252 patients treated with SBRT to 294 lung nodules. When comparing pre-Tx review completion from initial rollout to full implementation, our rates improved from 19% to 79% (ie, from 1 sigma limit [SDs]) below to >2 sigma limits (SDs) above. Additionally, early completion of any form of contour/plan review (defined as any pre-Tx or standard review completed before exceeding 25% of the dose delivered) increased from 67% to 85% (March 2020-November 2020) to 76% to 94% (December 2020-August 2021). Conclusions: We successfully implemented a sustainable workflow for detailed pre-Tx contour/plan review for thoracic SBRT cases in the context of twice-weekly disease site-specific peer-review meetings. We reached our quality improvement objective to peer review ≥90% of SBRT cases before exceeding 25% of the dose delivered. This process was feasible to conduct in an integrated network of sites across our system.

Prolonged Prone Position Ventilation Is Associated With Reduced Mortality in Intubated COVID-19 Patients.

BACKGROUND: Prone position ventilation (PPV) is resource-intensive, yet the optimal strategy for PPV in intubated patients with COVID-19 is unclear. RESEARCH QUESTION: Does a prolonged (24 or more h) PPV strategy improve mortality in intubated COVID-19 patients compared with intermittent (∼16 h with daily supination) PPV? STUDY DESIGN AND METHODS: Multicenter, retrospective cohort study of consecutively admitted intubated COVID-19 patients treated with PPV between March 11 and May 31, 2020. The primary outcome was 30-day all-cause mortality. Secondary outcomes included 90-day all-cause mortality and prone-related complications. Inverse probability treatment weights (IPTW) were used to control for potential treatment selection bias. RESULTS: Of the COVID-19 patients who received PPV, 157 underwent prolonged and 110 underwent intermittent PPV. Patients undergoing prolonged PPV had reduced 30-day (adjusted hazard ratio [aHR], 0.475; 95% CI, 0.336-0.670; P < .001) and 90-day (aHR, 0.638; 95% CI, 0.461-0.883; P = .006) mortality compared with intermittent PPV. In patients with Pao2/Fio2 ≤ 150 at the time of pronation, prolonged PPV was associated with reduced 30-day (aHR, 0.357; 95% CI, 0.213-0.597; P < .001) and 90-day mortality (aHR, 0.562; 95% CI, 0.357-0.884; P = .008). Patients treated with prolonged PPV underwent fewer pronation and supination events (median, 1; 95% CI, 1-2 vs 3; 95% CI, 1-4; P < .001). PPV strategy was not associated with overall PPV-related complications, although patients receiving prolonged PPV had increased rates of facial edema and lower rates of peri-proning hypotension. INTERPRETATION: Among intubated COVID-19 patients who received PPV, prolonged PPV was associated with reduced mortality. Prolonged PPV was associated with fewer pronation and supination events and a small increase in rates of facial edema. These findings suggest that prolonged PPV is a safe, effective strategy for mortality reduction in intubated COVID-19 patients.

Preferred Language Mediates Association Between Race, Ethnicity, and Delayed Presentation in Critically Ill Patients With COVID-19.

Which social factors explain racial and ethnic disparities in COVID-19 access to care and outcomes remain unclear. OBJECTIVES: We hypothesized that preferred language mediates the association between race, ethnicity and delays to care. DESIGN SETTING AND PARTICIPANTS: Multicenter, retrospective cohort study of adults with COVID-19 consecutively admitted to the ICU in three Massachusetts hospitals in 2020. MAIN OUTCOME AND MEASURES: Causal mediation analysis was performed to evaluate potential mediators including preferred language, insurance status, and neighborhood characteristics. RESULTS: Non-Hispanic White (NHW) patients (157/442, 36%) were more likely to speak English as their preferred language (78% vs. 13%), were less likely to be un- or under-insured (1% vs. 28%), lived in neighborhoods with lower social vulnerability index (SVI) than patients from racial and ethnic minority groups (SVI percentile 59 [28] vs. 74 [21]) but had more comorbidities (Charlson comorbidity index 4.6 [2.5] vs. 3.0 [2.5]), and were older (70 [13.2] vs. 58 [15.1] years). From symptom onset, NHW patients were admitted 1.67 [0.71-2.63] days earlier than patients from racial and ethnic minority groups (p < 0.01). Non-English preferred language was associated with delay to admission of 1.29 [0.40-2.18] days (p < 0.01). Preferred language mediated 63% of the total effect (p = 0.02) between race, ethnicity and days from symptom onset to hospital admission. Insurance status, social vulnerability, and distance to the hospital were not on the causal pathway between race, ethnicity and delay to admission. CONCLUSIONS AND RELEVANCE: Preferred language mediates the association between race, ethnicity and delays to presentation for critically ill patients with COVID-19, although our results are limited by possible collider stratification bias. Effective COVID-19 treatments require early diagnosis, and delays are associated with increased mortality. Further research on the role preferred language plays in racial and ethnic disparities may identify effective solutions for equitable care.