Targeting CaMKK2 Inhibits Actin Cytoskeletal Assembly to Suppress Cancer Metastasis

Triple-negative breast cancers (TNBC) tend to become invasive and metastatic at early stages in their development. Despite some treatment successes in early-stage localized TNBC, the rate of distant recurrence remains high, and long-term survival outcomes remain poor. In a search for new therapeutic targets for this disease, we observed that elevated expression of the serine/threonine kinase calcium/calmodulin (CaM)-dependent protein kinase kinase 2 (CaMKK2) is highly correlated with tumor invasiveness. In validation studies, genetic disruption of CaMKK2 expression or inhibition of its activity with small molecule inhibitors disrupted spontaneous metastatic outgrowth from primary tumors in murine xenograft models of TNBC. High-grade serous ovarian cancer (HGSOC), a high-risk, poor prognosis ovarian cancer subtype, shares many features with TNBC, and CaMKK2 inhibition effectively blocked metastatic progression in a validated xenograft model of this disease. Mechanistically, CaMKK2 increased the expression of the phosphodiesterase PDE1A, which hydrolyzed cyclic guanosine monophosphate (cGMP) to decrease the cGMP-dependent activity of protein kinase G1 (PKG1). Inhibition of PKG1 resulted in decreased phosphorylation of vasodilator-stimulated phosphoprotein (VASP), which in its hypophosphorylated state binds to and regulates F-actin assembly to facilitate cell movement. Together, these findings establish a targetable CaMKK2-PDE1A-PKG1-VASP signaling pathway that controls cancer cell motility and metastasis by impacting the actin cytoskeleton. Furthermore, it identifies CaMKK2 as a potential therapeutic target that can be exploited to restrict tumor invasiveness in patients diagnosed with early-stage TNBC or localized HGSOC.

SIGNIFICANCE

CaMKK2 regulates actin cytoskeletal dynamics to promote tumor invasiveness and can be inhibited to suppress metastasis of breast and ovarian cancer, indicating CaMKK2 inhibition as a therapeutic strategy to arrest disease progression.

Ca 2+ /Calmodulin Dependent Protein Kinase Kinase-2 (CaMKK2) promotes Protein Kinase G (PKG)-dependent actin cytoskeletal assembly to increase tumor metastasis

Triple-negative breast cancers (TNBCs) tend to become highly invasive early during cancer development. Despite some successes in the initial treatment of patients diagnosed with early-stage localized TNBC, the rate of metastatic recurrence remains high with poor long-term survival outcomes. Here we show that elevated expression of the serine/threonine-kinase, Calcium/Calmodulin (CaM)-dependent protein kinase kinase-2 (CaMKK2), is highly correlated with tumor invasiveness. We determined that genetic disruption of CaMKK2 expression, or inhibition of its activity, disrupted spontaneous metastatic outgrowth from primary tumors in murine xenograft models of TNBC. High-grade serous ovarian cancer (HGSOC), a high-risk, poor-prognosis ovarian cancer subtype, shares many genetic features with TNBC, and importantly, CaMKK2 inhibition effectively blocked metastatic progression in a validated xenograft model of this disease. Probing the mechanistic links between CaMKK2 and metastasis we defined the elements of a new signaling pathway that impacts actin cytoskeletal dynamics in a manner which increases cell migration/invasion and metastasis. Notably, CaMKK2 increases the expression of the phosphodiesterase PDE1A which decreases the cGMP-dependent activity of protein kinase G1 (PKG1). This inhibition of PKG1 results in decreased phosphorylation of Vasodilator-Stimulated Phosphoprotein (VASP), which in its hypophosphorylated state binds to and regulates F-actin assembly to facilitate contraction/cell movement. Together, these data establish a targetable CaMKK2-PDE1A-PKG1-VASP signaling pathway that controls cancer cell motility and metastasis. Further, it credentials CaMKK2 as a therapeutic target that can be exploited in the discovery of agents for use in the neoadjuvant/adjuvant setting to restrict tumor invasiveness in patients diagnosed with early-stage TNBC or localized HGSOC.

Regenerative vs flap-based limb salvage: a multi-centered, prospective, randomized controlled trial

Aim: The goal of this study was to compare success rates of a regenerative limb salvage approach (rLS) using dehydrated human chorion amnion membrane (dHACM) to traditional flap-based limb salvage (fLS). Materials & methods: This prospective RTC enrolled patients presenting with complex extremity wounds over a 3-year period. Primary outcomes included success of primary reconstruction, persistence of exposed structures, time to definitive closure, and time to weight bearing. Results: Patients meeting inclusion criteria were randomized to fLS (n = 14) or rLS (n = 25). The primary reconstructive method was successful for 85.7% of fLS subjects and 80% of rLS subjects (p = 1.00). Conclusion: This trial provides strong evidence that rLS is an effective option in the setting of complex extremity wounds, with success rates comparable to traditional flaps. Clinical Trial Registration: NCT03521258 (ClinicalTrials.gov).

The Impact of Exogenous Testosterone on Breast Cancer Risk in Transmasculine Individuals

BACKGROUND

Exogenous testosterone is vital to gender-affirming therapy for transmasculine individuals. Testosterone may be implicated in breast cancer (BCa) because it can activate androgen and estrogen receptors. To further explore this risk, we performed a systematic review to investigate the impact of exogenous testosterone on BCa risk in transmasculine individuals.

METHODS

We searched PubMed/MEDLINE and Ovid/Embase for clinical and preclinical studies assessing BCa and testosterone therapy and screened 6125 articles independently. We ascertained level of evidence using a modified tool from Cook et al (Chest. 1992;102:305S-311S) and risk of bias using a modified Joanna Briggs Institute's Critical Appraisal Tool.

RESULTS

Seventy-six studies were included. Epidemiological data suggested that BCa incidence was higher in transmasculine individuals compared with cisgender men but lower compared with cisgender women. Histological studies of transmasculine breast tissue samples also demonstrated a low incidence of precancerous lesions. Interestingly, cases demonstrated that BCa occurred at a younger average age in transmasculine individuals and was predominantly hormone receptor positive. The mechanism for BCa in transmasculine individuals may be related to androgen receptor stimulation or conversion to estradiol. Serum studies reported varied estradiol levels associated with exogenous testosterone. Animal and in vitro studies demonstrated that testosterone was growth inhibitory but may induce proliferation at higher doses or with low estradiol levels.

CONCLUSIONS

Plastic surgeons play a critical role in providing gender-affirming care for transmasculine patients. The limited studies available suggest that this patient population has decreased risk for BCa when compared with cisgender women; however, any BCa that does occur may have different clinical presentations and underlying mechanisms compared with cisgender women and men. Overall, the limitations for clinical studies and discrepancies among preclinical studies warrant further investigation.

Pilot study of minimally adherent silver dressings for acute surgical wounds

Background and Aims

Minimally adherent silver dressings (SILVER MASD) are antimicrobial, nonirritating, provide a moist wound healing environment, and low cost. The purpose of this pilot, single-center, non-blinded randomized controlled trial was to quantify the outcomes of acute surgical wounds treated with MASD versus standard of care (SoC) dressings.

Methods

Thirty-two patients with acute wounds were randomized 1:1 to be treated with MASD once weekly or SoC following surgical excision of skin and/or subcutaneous tissue between September 13, 2016 and November 28, 2017. The outcome variables included clinical infection, time to wound closure, and pain scores at dressing changes. Two independent, one-sided sample t-tests were performed to assess statistical significance.

Results

There was no difference in wound healing between SILVER MASD and SoC. Dressing changes were less painful for wounds managed with MASD silver dressings.

Conclusions

The results of this study suggest that MASD are not less effective in wound healing compared to SoC while also providing the benefit of decreased pain at dressing changes. Therefore, minimally adherent silver dressings can and should be considered a viable option in the management of acute surgical wounds.

Treatment of a recurrent ischial ulcer with injected exosomes

Pressure ulcers (PUs) affect 2.5 million patients per year. Even after successful reconstruction, 50% of PUs recur. Patients with multiply recurrent PUs eventually consume all locoregional donor sites. This underscores the need for novel, less invasive approaches in PU reconstruction. Here, we report the first successful use of mesenchymal stem cell exosomes in PU reconstruction. The patient presented with a right ischial ulcer that persisted despite 9 months of wound care and appropriate antibiotic therapy. After six subcutaneous ExoFlo exosome injections over 8 weeks, the PU was completely healed. Additional studies of this promising technology should be performed.

Pilot Phase Results of a Prospective, Randomized Controlled Trial of Narrowband Ultraviolet B Phototherapy in Hospitalized COVID-19 Patients

COVID‐19 morbidity and mortality are driven by poor immune regulation. Narrowband ultraviolet B (NB‐UVB) phototherapy is standard of care in a number of immune‐dysregulated diseases. To assess the efficacy of NB‐UVB phototherapy for improving COVID‐19 outcomes in high‐risk, hospitalized, we developed the Adaptive Photo‐Protection Trial. This is a multi‐center, prospective, double‐blinded, randomized, placebo‐controlled trial. The pilot phase results are reported here. Consecutive patients admitted with a positive COVID‐19 PCR were screened for eligibility. Enrolled subjects were computer randomized 1:1 to NB‐UVB or placebo phototherapy. Subjects were treated daily with escalating doses on 27% of their body surface area for up to 8 consecutive days. Primary outcomes were safety and efficacy, defined as persistent or painful erythema and 28‐day mortality. Comparisons were made via non‐parametric exact tests. Patients in treatment (n = 15) and placebo (n = 15) arms had similar demographics. No adverse events occurred. Twenty eight‐day mortality was 13.3% in treatment vs. 33.3% in placebo arms (p = 0.39). NB‐UVB phototherapy in hospitalized COVID‐19 patients was safe. Decreased mortality was observed in treated patients but this was statistically non‐significant. Given its low‐cost, scalability, and adjunctive nature, NB‐UVB has the potential to improve COVID‐19 outcomes. Continuation of this trial is warranted.

Expression of the preadipocyte marker ZFP423 is dysregulated between well-differentiated and dedifferentiated liposarcoma

Background

Well-differentiated and dedifferentiated liposarcomas are rare soft tissue tumors originating in adipose tissue that share genetic abnormalities but have significantly different metastatic potential. Dedifferentiated liposarcoma (DDLPS) is highly aggressive and has an overall 5-year survival rate of 30% as compared to 90% for well-differentiated liposarcoma (WDLPS). This discrepancy may be connected to their potential to form adipocytes, where WDLPS is adipogenic but DDLPS is adipogenic-impaired. Normal adipogenesis requires Zinc Finger Protein 423 (ZFP423), a transcriptional coregulator of Perixosome Proliferator Activated Receptor gamma (PPARG2) mRNA expression that defines committed preadipocytes. Expression of ZFP423 in preadipocytes is promoted by Seven-In-Absentia Homolog 2 (SIAH2)-mediated degradation of Zinc Finger Protein 521 (ZFP521). This study investigated the potential role of ZFP423, SIAH2 and ZFP521 in the adipogenic potential of WDLPS and DDLPS.

Methods

Human WDLPS and DDLPS fresh and paraffin-embedded tissues were used to assess the gene and protein expression of proadipogenic regulators. In parallel, normal adipose tissue stromal cells along with WDLPS and DDLPS cell lines were cultured, genetically modified, and induced to undergo adipogenesis in vitro.

Results

Impaired adipogenic potential in DDLPS was associated with reduced ZFP423 protein levels in parallel with reduced PPARG2 expression, potentially involving regulation of ZFP521. SIAH2 protein levels did not define a clear distinction related to adipogenesis in these liposarcomas. However, in primary tumor specimens, SIAH2 mRNA was consistently upregulated in DDLPS compared to WDLPS when assayed by fluorescence in situ hybridization or real-time PCR.

Conclusions

These data provide novel insights into ZFP423 expression in adipogenic regulation between WDLPS and DDLPS adipocytic tumor development. The data also introduces SIAH2 mRNA levels as a possible molecular marker to distinguish between WDLPS and DDLPS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09379-6.

A Role for Adipocytes and Adipose Stem Cells in the Breast Tumor Microenvironment and Regenerative Medicine

Obesity rates are climbing, representing a confounding and contributing factor to many disease states, including cancer. With respect to breast cancer, obesity plays a prominent role in the etiology of this disease, with certain subtypes such as triple-negative breast cancer having a strong correlation between obesity and poor outcomes. Therefore, it is critical to examine the obesity-related alterations to the normal stroma and the tumor microenvironment (TME). Adipocytes and adipose stem cells (ASCs) are major components of breast tissue stroma that have essential functions in both physiological and pathological states, including energy storage and metabolic homeostasis, physical support of breast epithelial cells, and directing inflammatory and wound healing responses through secreted factors. However, these processes can become dysregulated in both metabolic disorders, such as obesity and also in the context of breast cancer. Given the well-established obesity-neoplasia axis, it is critical to understand how interactions between different cell types in the tumor microenvironment, including adipocytes and ASCs, govern carcinogenesis, tumorigenesis, and ultimately metastasis. ASCs and adipocytes have multifactorial roles in cancer progression; however, due to the plastic nature of these cells, they also have a role in regenerative medicine, making them promising tools for tissue engineering. At the physiological level, the interactions between obesity and breast cancer have been examined; here, we will delineate the mechanisms that regulate ASCs and adipocytes in these different contexts through interactions between cancer cells, immune cells, and other cell types present in the tumor microenvironment. We will define the current state of understanding of how adipocytes and ASCs contribute to tumor progression through their role in the tumor microenvironment and how this is altered in the context of obesity. We will also introduce recent developments in utilizing adipocytes and ASCs in novel approaches to breast reconstruction and regenerative medicine.

Dehydrated Human Amniotic-Chorionic Membrane Reduces Incisional Hernia Formation in an Animal Model

BACKGROUND

Currently there are no standard of care treatment strategies for IH prevention (IHP). Dehydrated human amnion-chorion (dHACM) is a healing adjunct that elutes growth factors including several that have reduced IH in animal models. We therefore performed a double-blinded, prospective randomized controlled trial (RCT) to test the hypothesis that dHACM significantly reduces IH formation in a well-studied animal model of acute IH.

MATERIAL AND METHODS

Forty 16-week-old male Sprague-Dawley rats were randomized to one of four groups: No Treatment vs. dHACM Sheet (Group A), and Saline vs. dHACM Injection (Group B). Each animal underwent a 5-cm midline laparotomy which was incompletely closed with 5-0 plain gut sutures; this was performed by a surgeon blinded to treatment group (first blind). After 28 days, the primary endpoints of IH formation and hernia size were determined by study staff blinded to treatment (second blind). Secondary endpoints included healed fascia tensile strength as determined by tensiometry, systemic and local inflammatory markers as measured by ELISA, and fascial scar collagen I/III ratios per Western blotting.

RESULTS

In Group A, No Treatment developed IH at 87.5% vs. 62.5% for Sheet (P = 0.28). Hernias that formed in the Sheet group were significantly smaller (P = 0.036). In Group B, Injection and Saline yielded identical IH rates of 77.8%. Molecular characterization of fascial scar demonstrated non-inferior tensile strength, collagen I/III ratios, and inflammatory markers in dHACM-treated animals.

CONCLUSIONS

dHACM sheets significantly reduced the size of IH following laparotomy when compared to no treatment.

Free Tissue Transfer in Pressure Ulcer Reconstruction: A Systematic Review

Background Pressure ulcers (PUs) affect 2.5 million people in the United States annually and incur health-care costs of 11 billion dollars annually. Stage III/IV PU often require local flap reconstruction. Unfortunately, PU recurrence is common following reconstruction; recurrence rates as high as 82% have been reported. When local flap options are inadequate, free tissue transfer may be indicated but the indications have yet to be delineated. To develop evidence-based guidelines for the use of free flaps in PU reconstruction, we performed a systematic review.

Methods A systematic review of the available English-language, peer-reviewed literature was conducted using PubMed/MEDLINE, Google Scholar, Scopus, EMBASE, and the Cochrane Database of Systematic Reviews. Articles were manually reviewed for relevance.

Results Out of 272 articles identified, 10 articles were included in the final analysis. Overall, this systematic review suggests that free-flap PU reconstruction yields fewer recurrences compared with local flaps (0–20 vs. 13–82%). Further, several types of free flaps for PU reconstruction were identified in this review, along with their indications.

Conclusion Free tissue transfer should be considered for recurrent PU. We offer specific recommendations for their use in PU reconstruction.

Modeling Breast Cancer in Human Breast Tissue using a Microphysiological System

Breast cancer (BC) remains a leading cause of death for women. Despite more than $700 million invested in BC research annually, 97% of candidate BC drugs fail clinical trials. Therefore, new models are needed to improve our understanding of the disease. The NIH Microphysiological Systems (MPS) program was developed to improve the clinical translation of basic science discoveries and promising new therapeutic strategies. Here we present a method for generating MPS for breast cancers (BC-MPS). This model adapts a previously described approach of culturing primary human white adipose tissue (WAT) by sandwiching WAT between adipose-derived stem cell sheets (ASC)s. Novel aspects of our BC-MPS include seeding BC cells into non-diseased human breast tissue (HBT) containing native extracellular matrix, mature adipocytes, resident fibroblasts, and immune cells; and sandwiching the BC-HBT admixture between HBT-derived ASC sheets. The resulting BC-MPS is stable in culture ex vivo for at least 14 days. This model system contains multiple elements of the microenvironment that influence BC including adipocytes, stromal cells, immune cells, and the extracellular matrix. Thus BC-MPS can be used to study the interactions between BC and its microenvironment. We demonstrate the advantages of our BC-MPS by studying two BC behaviors known to influence cancer progression and metastasis: 1) BC motility and 2) BC-HBT metabolic crosstalk. While BC motility has previously been demonstrated using intravital imaging, BC-MPS allows for high-resolution time-lapse imaging using fluorescence microscopy over several days. Furthermore, while metabolic crosstalk was previously demonstrated using BC cells and murine pre-adipocytes differentiated into immature adipocytes, our BC-MPS model is the first system to demonstrate this crosstalk between primary human mammary adipocytes and BC cells in vitro.

Quantifying Breast Cancer-Driven Fiber Alignment and Collagen Deposition in Primary Human Breast Tissue

Solid tumor progression is significantly influenced by interactions between cancer cells and the surrounding extracellular matrix (ECM). Specifically, the cancer cell-driven changes to ECM fiber alignment and collagen deposition impact tumor growth and metastasis. Current methods of quantifying these processes are incomplete, require simple or artificial matrixes, rely on uncommon imaging techniques, preclude the use of biological and technical replicates, require destruction of the tissue, or are prone to segmentation errors. We present a set of methodological solutions to these shortcomings that were developed to quantify these processes in cultured, ex vivo human breast tissue under the influence of breast cancer cells and allow for the study of ECM in primary breast tumors. Herein, we describe a method of quantifying fiber alignment that can analyze complex native ECM from scanning electron micrographs that does not preclude the use of replicates and a high-throughput mechanism of quantifying collagen content that is non-destructive. The use of these methods accurately recapitulated cancer cell-driven changes in fiber alignment and collagen deposition observed by visual inspection. Additionally, these methods successfully identified increased fiber alignment in primary human breast tumors when compared to human breast tissue and increased collagen deposition in lobular breast cancer when compared to ductal breast cancer. The successful quantification of fiber alignment and collagen deposition using these methods encourages their use for future studies of ECM dysregulation in human solid tumors.

Regenerative Limb Salvage: A Novel Technique for Soft Tissue Reconstruction of Pediatric Extremities

Background In complex extremity wounds, free flap-based limb salvage (fLS) is the standard of care. However, fLS is resource- and cost-intensive, and the limited availability of pediatric microsurgical expertise exacerbates these challenges. Regenerative LS (rLS) addresses these barriers to care. The aim of this study was to quantify the efficacy, safety, and cost-effectiveness of rLS in complex pediatric extremity wounds.

Methods We conducted a retrospective cohort study of pediatric LS at a single hospital. Subjects were treated with fLS or rLS based on surgeon preference. Primary outcome measures were: definitive wound closure rates and time, rates of return to ambulation, number and length of procedures to achieve definitive closure, and rates of perioperative complications. Statistical analyses were performed utilizing the Wilcoxon Mann–Whitney U test with statistical significance set at p < 0.05.

Results Over a 2-year period, nine consecutive patients presented with complex extremity wounds requiring fLS (n = 4) or rLS (n = 5). Demographics and wound characteristics were similar between groups. Compared with fLS, the rLS group achieved definitive wound closure 85.8% more quickly (13.8 vs. 97.5 days, p < 0.02), required 64.5% less operative time (132.6 vs. 373.0 minutes, p < 0.02), had fewer perioperative complications (0 vs. 5), and required fewer intensive care unit stays (0 vs. 1.3 days).

Conclusion These data indicate that rLS is a safe and efficacious option in pediatric patients requiring soft tissue reconstruction for LS. Use of this novel technique can restore the reconstructive ladder, thereby expand patient access to pediatric LS while minimizing morbidity and reducing LS-related resource utilization.

Patient-Derived Xenografts as an Innovative Surrogate Tumor Model for the Investigation of Health Disparities in Triple Negative Breast Cancer

Despite a decline in overall incidence rates for cancer in the past decade, due in part to impressive advancements in both diagnosis and treatment, breast cancer (BC) remains the leading cause of cancer-related deaths in women. BC alone accounts for ∼30% of all new cancer diagnoses in women worldwide. Triple-negative BC (TNBC), defined as having no expression of the estrogen or progesterone receptors and no amplification of the HER2 receptor, is a subtype of BC that does not benefit from the use of estrogen receptor-targeting or HER2-targeting therapies. Differences in socioeconomic factors and cell intrinsic and extrinsic characteristics have been demonstrated in Black and White TNBC patient tumors. The emergence of patient-derived xenograft (PDX) models as a surrogate, translational, and functional representation of the patient with TNBC has led to the advances in drug discovery and testing of novel targeted approaches and combination therapies. However, current established TNBC PDX models fail to represent the diverse patient population and, most importantly, the specific ethnic patient populations that have higher rates of incidence and mortality. The primary aim of this review is to emphasize the importance of using clinically relevant translatable tumor models that reflect TNBC human tumor biology and heterogeneity in high-risk patient populations. The focus is to highlight the complexity of BC as it specifically relates to the management of TNBC in Black women. We discuss the importance of utilizing PDX models to study the extracellular matrix (ECM), and the distinct differences in ECM composition and biophysical properties in Black and White women. Finally, we demonstrate the crucial importance of PDX models toward novel drug discovery in this patient population.

Health Disparities in Incisional Hernia Presentation : An Analysis of HCUP-NIS Years 2012-2014

INTRODUCTION

Incisional hernias (IH) are iatrogenically created in 400 000 new patients annually. Without repair, IH-associated complications can result in major illness and death. The health disparities literature suggests that under-represented patients present more frequently with surgical emergencies. The health disparities associated with IH remain relatively unstudied.

METHODS

Inpatient admission data were obtained from the Healthcare Cost and Utilization Project National Inpatient Sample for 2012-2014. Patients with IH International Classification of Diseases ninth revision were included. Analyses were completed using survey specific procedures (SAS v.9.4). Type of admission within groups was compared via Rao-Scott chi-square tests. The probability of an elective admission was modeled via SurveyLogistic Procedure.

RESULTS

Of 39 296 cases, 38.5% IH admissions were urgent or emergent (nonelective). The proportion of nonelective admission was statistically higher (P < .0001) in patients >65 (40.9%) and females (40.3%). Among insurance types, self-paying patients had the highest proportion of nonelective admissions (64.3%). Racial disparities remained significant after adjusting for age, sex, and insurance. Compared with white patients, the odds of an admission being nonelective were significantly higher for black (odds ratio [OR] [95% CI]: 1.65 [1.53-1.77]], Hispanic (OR [95% CI]: 1.39 [1.28-1.51]), and other (OR [95% CI]: 1.2 [1.06-1.37]) patients.

DISCUSSION

These data show that multiple at-risk patient populations are significantly more likely to require urgent admission for IH-related complications. These include older, female, non-white, and uninsured patients. Systematic efforts to ameliorate these disparities should be developed.

Prevalence of Accessory Branches and Other Anatomical Variations in the Radial Artery Encountered during Radial Forearm Flap Harvest: A Systematic Review and Meta-analysis

Background Harvest of the radial forearm flap (RFF) for reconstructive surgery is proceeded by the Allen test to assess for adequate contralateral perfusion of the hand, yet the Allen test may fail to detect anatomical variations in the radial artery such as aberrant branching. Therefore, the goal of this study was to systematically review the literature regarding anatomical abnormalities of the radial artery that can affect flap harvest and to perform a meta-analysis to estimate the prevalence of such abnormalities.

Methods A systematic review of the literature was conducted using five online databases to identify all instances of radial artery anatomical variations. Abstracts were reviewed and categorized into either (1) large cohort studies of anatomical variations identified by angiogram or (2) case reports specifically mentioning anomalous or accessory branches of the radial artery. Data from the large cohort studies were included in a random effect meta-analysis to estimate the prevalence of such variations.

Results Eighteen angiogram cohort studies containing a total of 18,115 patients were included in the meta-analysis. Accessory branches were the least common anatomical variant reported, with an estimated average prevalence of 0.5%. Prevalence estimates for more common anatomical variants, including radial artery loops (0.9%), stenosis (1.3%), hypoplasia (1.9%), tortuosity (4.3%), and abnormal origin (5.6%), were also calculated. Thirteen case reports detailing anomalous branches of the radial artery were identified, seven of which involved accessory branches encountered during RFF harvest with no incidence of flap loss.

Conclusion Radial artery accessory branches are exceedingly rare, but the prevalence of other anatomical variations that can affect harvest of the RFF warrants consideration. We recommend surgeons consider comprehensive screening prior to RFF harvest to avoid intraoperative discovery of anatomical variants and suggest a low threshold for repeat perfusion testing intraoperatively if radial artery accessory branches are encountered.

Naringenin Promotes Thermogenic Gene Expression in Human White Adipose Tissue

OBJECTIVE

Naringenin, a citrus flavonoid, prevents diet-induced weight gain and improves glucose and lipid metabolism in rodents. There is evidence that naringenin activates brown fat and increases energy expenditure in mice, but little is known about its effects in humans. The goal of this study was to examine the effects of naringenin on energy expenditure in adipose tissue.

METHODS

Human white adipocyte cultures (hADSC) and abdominal subcutaneous adipose tissue (pWAT) were treated with naringenin for 7 to 14 days. Expression (quantitative real-time polymerase chain reaction, immunoblotting) of candidate genes involved in thermogenesis and glucose metabolism was measured. Oxygen consumption rate was measured in hADSC using a Seahorse flux analyzer.

RESULTS

In hADSC, naringenin increased expression of the genes associated with thermogenesis and fat oxidation, including uncoupling protein 1 and adipose triglyceride lipase, and key factors associated with insulin sensitivity, including glucose transporter type 4, adiponectin, and carbohydrate-responsive element-binding protein (P < 0.01). Similar responses were observed in pWAT. Basal, ATP-linked, maximal and reserve oxygen consumption rate increased in the naringenin-treated hADSC (P < 0.01).

CONCLUSIONS

Naringenin increases energy expenditure in hADSC and stimulates expression of key enzymes involved in thermogenesis and insulin sensitivity in hADSC and pWAT. Naringenin may promote conversion of human white adipose tissue to a brown/beige phenotype.

A Microphysiologic Platform for Human Fat: Sandwiched White Adipose Tissue

White adipose tissue (WAT) plays a crucial role in regulating weight and everyday health. Still, there are significant limitations to available primary culture models, all of which have failed to faithfully recapitulate the adipose microenvironment or extend WAT viability beyond two weeks. The lack of a reliable primary culture model severely impedes research in WAT metabolism and drug development. To this end we have utilized NIH's standards of a microphysiologic system to develop a novel platform for WAT primary culture called 'SWAT' (sandwiched white adipose tissue). We overcome the natural buoyancy of adipocytes by sandwiching minced WAT clusters between sheets of adipose-derived stromal cells. In this construct, WAT samples are viable over eight weeks in culture. SWAT maintains the intact ECM, cell-to-cell contacts, and physical pressures of in vivo WAT conditions; additionally, SWAT maintains a robust transcriptional profile, sensitivity to exogenous chemical signaling, and whole tissue function. SWAT represents a simple, reproducible, and effective method of primary adipose culture. Potentially, it is a broadly applicable platform for research in WAT physiology, pathophysiology, metabolism, and pharmaceutical development.

Sandwiched White Adipose Tissue: A Microphysiological System of Primary Human Adipose Tissue

White adipose tissue (WAT) is a critical organ in both health and disease. However, physiologically faithful tissue culture models of primary human WAT remain limited, at best. In this study we describe a novel WAT culture system in which primary human WAT is sandwiched between tissue-engineered sheets of adipose-derived stromal cells. This construct, called "sandwiched white adipose tissue" (SWAT), can be defined as a microphysiological system (MPS) since it is a tissue-engineered, multicellular, three-dimensional organ construct produced using human cells. We validated SWAT against the National Institutes of Health MPS standards and found that SWAT is viable in culture for 8 weeks, retains physiologic responses to exogenous signaling, secretes adipokines, and engrafts into animal models. These attributes position SWAT as a powerful tool for the study of WAT physiology, pathophysiology, personalized medicine, and pharmaceutical development.

Variations in the Anterolateral Thigh Flap's Vascular Anatomy in African Americans

BACKGROUND

 Variations in anterolateral thigh (ALT) arterial anatomy are well documented. Ethnicity is a known risk factor for vascular variation in several organ systems, but its impact on ALT anatomy has not been studied. Anecdotally, we observed frequent ALT arterial variation in African American (AA) patients. We thus hypothesized that AA patients have higher rates of anomalous branching.

MATERIALS AND METHODS

 A total of 277 computed tomography angiograms (513 lower extremities) captured between May 1, 2013 and May 31, 2015 at a tertiary academic medical center were retrospectively analyzed to determine ALT arterial branching. Patient records were examined to ascertain demographics. Data were analyzed using descriptive statistics and multinomial logistic regression.

RESULTS

 Males comprised 84.5%. Ethnic distribution was 55.2% AA and 36.5% Caucasian. The descending branch of the lateral circumflex femoral artery (dLCFA) originated from non-LCFA arteries (deep femoral, common femoral, or superficial femoral arteries) in 18.9% of Caucasian versus 9.1% of AA (odds ratio [OR]: 2.28; 95% confidence interval [CI]: 1.33-3.93, p < 0.01). An oblique branch was identified in 41.1% of Caucasian versus 51.9% of AA (OR: 1.56; 95% CI: 1.08-2.24, p = 0.02). Ethnicity was the only driving factor of dLCFA and oblique branch of the LCFA (oLCFA) anatomy (Wald chi-square: 14 and 11, p = 0.03 and 0.02, respectively).

CONCLUSIONS

 Ethnicity significantly affects ALT arterial anatomy. AA are more likely to have classical dLCFA branching with a fourth oLCFA branch. A flap with an unrecognized oLCFA-dominant supply places patients at a higher risk for flap failure and loss. We recommend preoperative imaging before undertaking an ALT flap reconstruction.

Characterization of bipolar disorder patient-specific induced pluripotent stem cells from a family reveals neurodevelopmental and mRNA expression abnormalities

Bipolar disorder (BD) is a common neuropsychiatric disorder characterized by chronic recurrent episodes of depression and mania. Despite evidence for high heritability of BD, little is known about its underlying pathophysiology. To develop new tools for investigating the molecular and cellular basis of BD, we applied a family-based paradigm to derive and characterize a set of 12 induced pluripotent stem cell (iPSC) lines from a quartet consisting of two BD-affected brothers and their two unaffected parents. Initially, no significant phenotypic differences were observed between iPSCs derived from the different family members. However, upon directed neural differentiation, we observed that CXCR4 (CXC chemokine receptor-4) expressing central nervous system (CNS) neural progenitor cells (NPCs) from both BD patients compared with their unaffected parents exhibited multiple phenotypic differences at the level of neurogenesis and expression of genes critical for neuroplasticity, including WNT pathway components and ion channel subunits. Treatment of the CXCR4(+) NPCs with a pharmacological inhibitor of glycogen synthase kinase 3, a known regulator of WNT signaling, was found to rescue a progenitor proliferation deficit in the BD patient NPCs. Taken together, these studies provide new cellular tools for dissecting the pathophysiology of BD and evidence for dysregulation of key pathways involved in neurodevelopment and neuroplasticity. Future generation of additional iPSCs following a family-based paradigm for modeling complex neuropsychiatric disorders in conjunction with in-depth phenotyping holds promise for providing insights into the pathophysiological substrates of BD and is likely to inform the development of targeted therapeutics for its treatment and ideally prevention.

Wound healing in acutely injured fascia

Fascial healing following acute injury, such as that occurring during surgical procedures, is defined functionally. For example, failure of fascial healing following celiotomy is only identified when incisional hernias are diagnosed. Such hernias incur billions of dollars per year in medical costs. Despite the importance of fascial healing, there is a paucity of data regarding the quality such healing. In clinical settings, the quantification of fascial wound healing is limited to a binary state: either there is no clinically apparent functional deficit and full fascia healing is assumed, or an incisional hernia or other functional failure is visible and the fascia did not heal. There are no clinical methods to isolate and functionally test fascia in patients. Recent studies have revealed unexpected findings regarding the recovery of tensile strength, specific surgical methods that optimize fascial healing, and the potential impact of biological pharmaceuticals in eliminating fascial healing failure. However, much remains unknown about the biology of fascial healing.

Expression analysis of macrodactyly identifies pleiotrophin upregulation

Macrodactyly is a rare family of congenital disorders characterized by the diffuse enlargement of 1 or more digits. Multiple tissue types within the affected digits are involved, but skeletal patterning and gross morphological features are preserved. Not all tissues are equally involved and there is marked heterogeneity with respect to clinical phenotype. The molecular mechanisms responsible for these growth disturbances offer unique insight into normal limb growth and development, in general. To date, no genes or loci have been implicated in the development of macrodactyly. In this study, we performed the first transcriptional profiling of macrodactyly tissue. We found that pleiotrophin (PTN) was significantly overexpressed across all our macrodactyly samples. The mitogenic functions of PTN correlate closely with the clinical characteristics of macrodactyly. PTN thus represents a promising target for further investigation into the etiology of overgrowth phenotypes.

Efficient culturing and genetic manipulation of human pluripotent stem cells

Human pluripotent stem cells (hPSC) hold great promise as models for understanding disease and as a source of cells for transplantation therapies. However, the lack of simple, robust and efficient culture methods remains a significant obstacle for realizing the utility of hPSCs. Here we describe a platform for the culture of hPSCs that 1) allows for dissociation and replating of single cells, 2) significantly increases viability and replating efficiency, 3) improves freeze/thaw viability 4) improves cloning efficiency and 5) colony size variation. When combined with standard methodologies for genetic manipulation, we found that the enhanced culture platform allowed for lentiviral transduction rates of up to 95% and electroporation efficiencies of up to 25%, with a significant increase in the total number of antibiotic-selected colonies for screening for homologous recombination. We further demonstrated the utility of the enhanced culture platform by successfully targeting the ISL1 locus. We conclude that many of the difficulties associated with culturing and genetic manipulation of hPSCs can be addressed with optimized culture conditions, and we suggest that the use of the enhanced culture platform could greatly improve the ease of handling and general utility of hPSCs.

Pattern specification and immune response transcriptional signatures of pericardial and subcutaneous adipose tissue

Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality in the United States. Recent studies suggest that pericardial adipose tissue (PCAT) secretes inflammatory factors that contribute to the development of CVD. To better characterize the role of PCAT in the pathogenesis of disease, we performed a large-scale unbiased analysis of the transcriptional differences between PCAT and subcutaneous adipose tissue, analysing 53 microarrays across 19 individuals. As it was unknown whether PCAT-secreted factors are produced by adipocytes or cells in the supporting stromal fraction, we also sought to identify differentially expressed genes in isolated pericardial adipocytes vs. isolated subcutaneous adipocytes. Using microarray analysis, we found that: 1) pericardial adipose tissue and isolated pericardial adipocytes both overexpress atherosclerosis-promoting chemokines and 2) pericardial and subcutaneous fat depots, as well as isolated pericardial adipocytes and subcutaneous adipocytes, express specific patterns of homeobox genes. In contrast, a core set of lipid processing genes showed no significant overlap with differentially expressed transcripts. These depot-specific homeobox signatures and transcriptional profiles strongly suggest different functional roles for the pericardial and subcutaneous adipose depots. Further characterization of these inter-depot differences should be a research priority.

Responsiveness of the Michigan Hand Outcomes Questionnaire and physical measurements in outcome studies of distal radius fracture treatment

PURPOSE

Outcomes study of distal radius fracture (DRF) treatment has been hampered by an uncertainty regarding the most appropriate outcomes assessment tool to evaluate the effectiveness of treatment. This study aimed to measure the responsiveness of the Michigan Hand Outcomes Questionnaire (MHQ) and physical measurements to assess the value of these outcomes tools for DRF studies.

METHODS

Forty-seven patients prospectively completed the MHQ and physical testing at 3 months and 6 months (period 1) after open reduction and internal fixation of unstable DRFs. Thirty-seven patients prospectively completed the MHQ and physical testing at 6 months and 1 year after open reduction and internal fixation (period 2). Responsiveness to clinical change within each period was calculated with standardized response means (SRMs).

RESULTS

In period 1, all domains of the MHQ except aesthetics significantly improved. The SRMs were large for the overall score and for the work domain. The SRMs were medium for the pain, function, and activities of daily living domains. In period 1, the grip strength, pinch strength, and active wrist range of motion measurements significantly improved and had large SRMs. In period 2, the grip- and pinch-strength tests significantly improved and the SRMs were medium, whereas the active wrist range of motion had a small SRM.

CONCLUSIONS

Unlike other conditions such as carpal tunnel syndrome, for which the outcomes questionnaire is the most responsive measure, in DRF treatment both the MHQ and physical tests are responsive in measuring outcomes and should be reported for outcomes studies of DRFs. The MHQ and physical tests can be used for outcomes research related to DRF with the advantage of also being useful for assessing and comparing outcomes for other hand disorders.

William Darrach, MD: his life and his contribution to hand surgery

William Darrach popularized subperiosteal resection of the distal ulna for distal radioulnar joint dysfunction, a procedure also known as the Darrach procedure. He was also a major contributor to academic surgery and medical education, publishing at least 70 articles, most on the treatment of fractures. He was influential in organized medicine and served as Dean of the Columbia College of Physicians and Surgeons, Governor and Regent of the American College of Surgeons, President of the American Surgical Association, and President of the Association of the American Medical Colleges. His contributions to education, hand surgery, and fracture treatment methodology make him an important figure in medicine.

A Cost/Utility Analysis of Open Reduction and Internal Fixation versus Cast Immobilization for Acute Nondisplaced Mid-Waist Scaphoid Fractures

BACKGROUND

Open reduction and internal fixation and cast immobilization are both acceptable treatment options for nondisplaced waist fractures of the scaphoid. The authors conducted a cost/utility analysis to weigh open reduction and internal fixation against cast immobilization in the treatment of acute nondisplaced mid-waist scaphoid fractures.

METHODS

The authors used a decision-analytic model to calculate the outcomes and costs of open reduction and internal fixation and cast immobilization, assuming the societal perspective. Utilities were assessed from 50 randomly selected medical students using the time trade-off method. Outcome probabilities taken from the literature were factored into the calculation of quality-adjusted life-years associated with each treatment. The authors estimated medical costs using Medicare reimbursement rates, and costs of lost productivity were estimated by average wages obtained from the U.S. Bureau of Labor Statistics.

RESULTS

Open reduction and internal fixation offers greater quality-adjusted life-years compared with casting, with an increase ranging from 0.21 quality-adjusted life-years for the 25- to 34-year age group to 0.04 quality-adjusted life-years for the > or =65-year age group. Open reduction and internal fixation is less costly than casting ($7940 versus $13,851 per patient) because of a longer period of lost productivity with casting. Open reduction and internal fixation is therefore the dominant strategy. When considering only direct costs, the incremental cost/utility ratio for open reduction and internal fixation ranges from $5438 per quality-adjusted life-year for the 25- to 34-year age group to $11,420 for the 55- to 64-year age group, and $29,850 for the > or =65-year age group.

CONCLUSIONS

Compared with casting, open reduction and internal fixation is cost saving from the societal perspective ($5911 less per patient). When considering only direct costs, open reduction and internal fixation is cost-effective relative to other widely accepted interventions.

Survey research: a primer for hand surgery

Survey research is an important and commonly used research tool. The findings of survey research help set national practice guidelines and guide health care policy decision making. The process of survey design and administration is rigorous, complex, and involved. The Journal of Hand Surgery contains on average 3 articles involving surveys per issue. This report serves as a reference for readers of the many survey articles published in this journal. It also provides a guide for hand surgeons or others interested in how to conduct survey research.

Factors influencing residents' decisions to pursue a career in hand surgery: a national survey

PURPOSE

The number of programs offering hand surgery fellowships has remained approximately the same over a 6-year period while the number of fellows within these programs has decreased by 46%. This study aimed to identify factors that persuaded or dissuaded orthopedic and plastic surgery residents in choosing hand surgery as a career.

METHODS

We conducted a national survey of final-year orthopedic (n = 600) and plastic surgery (n = 177) residents. We developed an internet questionnaire based on literature review and focus group discussions. A Web site link was sent via e-mail to program directors of accredited orthopedic and plastic surgery programs for distribution of this anonymous survey to the residents. Factor analysis combined items into an "intellectual issues" category and a "lifestyle issues" category. Logistic regression was used to evaluate factors that predict an outcome of entering a hand surgery fellowship.

RESULTS

We achieved a 30% response rate. Respondents and nonrespondents were not significantly different in terms of gender and race. After controlling for age, gender, marital status, and specialty, residents who enjoyed the intellectual issues of the hand surgery field were more likely to pursue a hand surgery fellowship (odds ratio = 10.1; 95% confidence interval = 3.3-30.8). Although a positive attitude toward lifestyle issues of the hand surgery field tended to be associated with pursuit of a hand surgery fellowship, the relationship was much weaker (odds ratio = 2.5; 95% confidence interval = 0.8-7.3).

CONCLUSIONS

Lifestyle issues associated with a career in hand surgery such as low reimbursement and long hours were not the most important factors to residents when considering a career in the field. Residents pursued hand surgery primarily because of factors such as interest in and exposure to this field. To prevent a potential shortfall of hand surgeons, both orthopedic and plastic surgery programs must strengthen residents' exposure to hand surgery education in their training.

Silas Weir Mitchell, MD: the physician who discovered causalgia

Silas Weir Mitchell discovered and treated causalgia, a condition most often encountered by hand surgeons. He is considered the father of neurology as well as an early pioneer in scientific medicine. He was also a psychiatrist, toxicologist, author, poet, and a celebrity in America and Europe. His many skills and interests led his contemporaries to consider him a genius on par with Benjamin Franklin. His contributions to medicine and particularly hand surgery continue to resonate today.