Challenges and Opportunities in the Elective Management of Diverticulitis: Perspectives From a National Sample of Colorectal Surgeons.

BACKGROUND: Diverticulitis is a complex, heterogeneous disease process that affects a diverse population of patients. In the elective management of this disease, treatment guidelines have shifted toward patient-centered, individualized decision-making. It is not known what challenges surgeons face as they approach these nuanced treatment decisions in practice. OBJECTIVE: This study aimed to identify opportunities to support colorectal surgeons in elective diverticulitis treatment. DESIGN: This was a qualitative study using standardized, semistructured interviews to explore the perspectives of 29 colorectal surgeons recruited using a purposive sampling technique. Data were analyzed using an "open-coding" approach. SETTINGS: Interviews with a national sample of colorectal surgeons were conducted from a single center using an online video platform. PATIENTS: This study did not involve patients. MAIN OUTCOME MEASURES: Interviews explored surgeons' experiences treating diverticulitis in the elective setting, focusing on perceived challenges in providing patient-centered care as well as opportunities to improve treatment decisions. RESULTS: Our qualitative analysis identified an overarching challenge in elective diverticulitis management for surgeons: difficulty ensuring adequate patient understanding of the risks and benefits of various treatments. This was thought to be due to 1) preexisting patient expectations about treatment and 2) lack of data regarding long-term treatment outcomes. Surgeons identified 2 potential opportunities to combat these challenges: 1) patient education and 2) additional research regarding treatment outcomes, with potential for the development of diverticulitis-specific decision support tools. LIMITATIONS: These results are based on a national sample of colorectal surgeons, but they capture qualitative data that is not intended to provide generalizable findings. CONCLUSIONS: As surgeons work toward providing individualized care for diverticulitis patients, they find it difficult to adequately counsel patients regarding the patient-specific risks of various treatments. The results of this study identify specific contributors to this problem as well as potential targets for intervention, which can guide future efforts to support surgeons in providing patient-centered care. See Video Abstract . DESAFOS Y OPORTUNIDADES EN EL MANEJO ELECTIVO DE LA DIVERTICULITIS PERSPECTIVAS DE UNA MUESTRA NACIONAL DE CIRUJANOS COLORRECTALES: ANTECEDENTES:La diverticulitis es un proceso patológico complejo y heterogéneo que afecta a una población diversa de pacientes. En el manejo electivo de esta enfermedad, las pautas de tratamiento se han desplazado hacia una toma de decisiones individualizada y centrada en el paciente. No se sabe qué desafíos enfrentan los cirujanos al abordar estas decisiones de tratamiento matizadas en la práctica.OBJETIVO:Identificar oportunidades para apoyar a los cirujanos colorrectales en el tratamiento electivo de la diverticulitis.DISEÑO:Este fue un estudio cualitativo que utilizó entrevistas semiestructuradas estandarizadas para explorar las perspectivas de 29 cirujanos colorrectales reclutados mediante una técnica de muestreo intencional. Los datos se analizaron utilizando un enfoque de "codificación abierta".ESCENARIO:Las entrevistas con una muestra nacional de cirujanos colorrectales se realizaron desde un solo centro utilizando una plataforma de video en línea.PRINCIPALES MEDIDAS DE RESULTADO:Las entrevistas exploraron las experiencias de los cirujanos en el tratamiento de la diverticulitis en el entorno electivo, centrándose en los desafíos percibidos en la prestación de atención centrada en el paciente, así como en las oportunidades para mejorar las decisiones de tratamiento.RESULTADOS:Nuestro análisis cualitativo identificó un desafío general en el manejo de la diverticulitis electiva para los cirujanos: la dificultad para asegurar que el paciente comprenda adecuadamente los riesgos y beneficios de los diversos tratamientos. Se pensó que esto se debía a 1) las expectativas preexistentes del paciente sobre el tratamiento y 2) la falta de datos sobre los resultados del tratamiento a largo plazo. Los cirujanos identificaron dos oportunidades potenciales para combatir estos desafíos: 1) educación del paciente y 2) investigación adicional sobre los resultados del tratamiento, con potencial para el desarrollo de herramientas de apoyo a la toma de decisiones específicas para la diverticulitis.LIMITACIONES:Estos resultados se basan en una muestra nacional de cirujanos colorrectales, pero capturan datos cualitativos que no pretenden proporcionar hallazgos generalizables.CONCLUSIONES:A medida que los cirujanos trabajan para brindar atención individualizada a los pacientes con diverticulitis, les resulta difícil aconsejar adecuadamente a los pacientes sobre los riesgos específicos de los pacientes para los diversos tratamientos. Los resultados de este estudio identifican contribuyentes específicos a este problema, así como objetivos potenciales para la intervención, que pueden guiar los esfuerzos futuros para ayudar a los cirujanos a brindar atención centrada en el paciente. (Traducción-Dr. Felipe Bellolio ).

Fibroblast activation in response to TGFß1 is modulated by co-culture with endothelial cells in a vascular organ-on-chip platform.

Background: Tissue fibrosis is a major healthcare burden that affects various organs in the body for which no effective treatments exist. An underlying, emerging theme across organs and tissue types at early stages of fibrosis is the activation of pericytes and/or fibroblasts in the perivascular space. In hepatic tissue, it is well known that liver sinusoidal endothelial cells (EC) help maintain the quiescence of stellate cells, but whether this phenomenon holds true for other endothelial and perivascular cell types is not well studied. Methods: The goal of this work was to develop an organ-on-chip microvascular model to study the effect of EC co-culture on the activation of perivascular cells perturbed by the pro-fibrotic factor TGFß1. A high-throughput microfluidic platform, PREDICT96, that was capable of imparting physiologically relevant fluid shear stress on the cultured endothelium was utilized. Results: We first studied the activation response of several perivascular cell types and selected a cell source, human dermal fibroblasts, that exhibited medium-level activation in response to TGFß1. We also demonstrated that the PREDICT96 high flow pump triggered changes in select shear-responsive factors in human EC. We then found that the activation response of fibroblasts was significantly blunted in co-culture with EC compared to fibroblast mono-cultures. Subsequent studies with conditioned media demonstrated that EC-secreted factors play at least a partial role in suppressing the activation response. A Luminex panel and single cell RNA-sequencing study provided additional insight into potential EC-derived factors that could influence fibroblast activation. Conclusion: Overall, our findings showed that EC can reduce myofibroblast activation of perivascular cells in response to TGFß1. Further exploration of EC-derived factors as potential therapeutic targets in fibrosis is warranted.

Proteomic Profiling of Fallopian Tube-Derived Extracellular Vesicles Using a Microfluidic Tissue-on-Chip System.

The human fallopian tube epithelium (hFTE) is the site of fertilization, early embryo development, and the origin of most high-grade serous ovarian cancers (HGSOCs). Little is known about the content and functions of hFTE-derived small extracellular vesicles (sEVs) due to the limitations of biomaterials and proper culture methods. We have established a microfluidic platform to culture hFTE for EV collection with adequate yield for mass spectrometry-based proteomic profiling, and reported 295 common hFTE sEV proteins for the first time. These proteins are associated with exocytosis, neutrophil degranulation, and wound healing, and some are crucial for fertilization processes. In addition, by correlating sEV protein profiles with hFTE tissue transcripts characterized using GeoMx® Cancer Transcriptome Atlas, spatial transcriptomics analysis revealed cell-type-specific transcripts of hFTE that encode sEVs proteins, among which, FLNA, TUBB, JUP, and FLNC were differentially expressed in secretory cells, the precursor cells for HGSOC. Our study provides insights into the establishment of the baseline proteomic profile of sEVs derived from hFTE tissue, and its correlation with hFTE lineage-specific transcripts, which can be used to evaluate whether the fallopian tube shifts its sEV cargo during ovarian cancer carcinogenesis and the role of sEV proteins in fallopian tube reproductive functions.

Increased Local Testosterone Levels Alter Human Fallopian Tube mRNA Profile and Signaling.

Fallopian tube epithelium (FTE) plays a critical role in reproduction and can be the site where High Grade Serous Ovarian Carcinoma (HGSOC) originates. Tumorigenic oviductal cells, which are the murine equivalent of human fallopian tube secretory epithelial cells (FTSEC), enhance testosterone secretion by the ovary when co-cultured with the ovary, suggesting that testosterone is part of the signaling axis between the ovary and FTSEC. Furthermore, testosterone promotes proliferation of oviductal cells. Oral contraceptives, tubal ligation, and salpingectomy, which are all protective against developing ovarian cancer, also decrease circulating levels of androgen. In the current study, we investigated the effect of increased testosterone on FTE and found that testosterone upregulates wingless-type MMTV integration family, member 4 (WNT4) and induces migration and invasion of immortalized human fallopian tube cells. We profiled primary human fallopian tissues grown in the microfluidic system SOLO-microfluidic platform -(MFP) by RNA sequencing and found that p53 and its downstream target genes, such as paired box gene 2 (PAX2), cyclin-dependent kinase inhibitor 1A (CDK1A or p21), and cluster of differentiation 82 (CD82 or KAI1) were downregulated in response to testosterone treatment. A microfluidic platform, the PREDICT-Multi Organ System (PREDICT-MOS) was engineered to support insert technology that allowed for the study of cancer cell migration and invasion through Matrigel. Using this system, we found that testosterone enhanced FTE migration and invasion, which was reversed by the androgen receptor (AR) antagonist, bicalutamide. Testosterone also enhanced FTSEC adhesion to the ovarian stroma using murine ovaries. Overall, these results indicate that primary human fallopian tube tissue and immortalized FTSEC respond to testosterone to shift expression of genes that regulate invasion, while leveraging a new strategy to study migration in the presence of dynamic fluid flow.

Aldosterone: Renal Action and Physiological Effects.

Aldosterone exerts profound effects on renal and cardiovascular physiology. In the kidney, aldosterone acts to preserve electrolyte and acid-base balance in response to changes in dietary sodium (Na+ ) or potassium (K+ ) intake. These physiological actions, principally through activation of mineralocorticoid receptors (MRs), have important effects particularly in patients with renal and cardiovascular disease as demonstrated by multiple clinical trials. Multiple factors, be they genetic, humoral, dietary, or otherwise, can play a role in influencing the rate of aldosterone synthesis and secretion from the adrenal cortex. Normally, aldosterone secretion and action respond to dietary Na+ intake. In the kidney, the distal nephron and collecting duct are the main targets of aldosterone and MR action, which stimulates Na+ absorption in part via the epithelial Na+ channel (ENaC), the principal channel responsible for the fine-tuning of Na+ balance. Our understanding of the regulatory factors that allow aldosterone, via multiple signaling pathways, to function properly clearly implicates this hormone as central to many pathophysiological effects that become dysfunctional in disease states. Numerous pathologies that affect blood pressure (BP), electrolyte balance, and overall cardiovascular health are due to abnormal secretion of aldosterone, mutations in MR, ENaC, or effectors and modulators of their action. Study of the mechanisms of these pathologies has allowed researchers and clinicians to create novel dietary and pharmacological targets to improve human health. This article covers the regulation of aldosterone synthesis and secretion, receptors, effector molecules, and signaling pathways that modulate its action in the kidney. We also consider the role of aldosterone in disease and the benefit of mineralocorticoid antagonists. © 2023 American Physiological Society. Compr Physiol 13:4409-4491, 2023.

Surgical Trainee Perspectives on the Opioid Crisis: The Influence of Explicit and Hidden Curricula.

OBJECTIVE: In order to effectively create and implement an educational program to improve opioid prescribing practices, it is important to first consider the unique perspectives of residents on the frontlines of the opioid epidemic. We sought to better understand resident perspectives on opioid prescribing, current practices in pain management, and opioid education as a needs assessment for designing future educational interventions. DESIGN: This is a qualitative study using focus groups of surgical residents at 4 different institutions. SETTING: We conducted focus groups using a semistructured interview guide in person or over video conferencing. The residency programs selected for participation represent a broad geographic range and varying residency sizes. PARTICIPANTS: We used purposeful sampling to recruit general surgery residents from the University of Utah, University of Wisconsin, Dartmouth-Hitchcock Medical Center, and the University of Alabama at Birmingham. All general surgery residents at these locations were eligible for inclusion. Participants were assigned to focus groups by residency site and their status as junior (PGY-2, PGY-3) or senior resident (PGY-4, PGY-5). RESULTS: We completed 8 focus groups with a total of 35 residents included. We identified 4 main themes. First, residents relied on clinical and nonclinical factors when making decisions about opioid prescribing. However, hidden curricula based on unique institutional cultures and attending preferences heavily influenced residents' prescribing practices. Second, residents acknowledged that stigma and biases towards certain patient groups influenced opioid prescribing practices. Third, residents encountered barriers within their health systems to evidence-based opioid prescribing. Fourth, residents did not routinely receive formal education on pain management or opioid prescribing. Residents recommended several interventions to improve the current state of opioid prescribing, including standardized prescribing guidelines, improved patient education, and formal training during the first year of residency. CONCLUSIONS: Our study highlighted several areas of opioid prescribing that can be improved upon through educational interventions. These findings can be used to develop programs aimed at improving residents' opioid prescribing practices, both during and after training, and ultimately the safe care of surgical patients. ETHICS STATEMENT: This project was approved by the University of Utah Institutional Review Board, ID # 00118491. All participants provided written informed consent.

A high-throughput, 28-day, microfluidic model of gingival tissue inflammation and recovery.

Nearly half of American adults suffer from gum disease, including mild inflammation of gingival tissue, known as gingivitis. Currently, advances in therapeutic treatments are hampered by a lack of mechanistic understanding of disease progression in physiologically relevant vascularized tissues. To address this, we present a high-throughput microfluidic organ-on-chip model of human gingival tissue containing keratinocytes, fibroblast and endothelial cells. We show the triculture model exhibits physiological tissue structure, mucosal barrier formation, and protein biomarker expression and secretion over several weeks. Through inflammatory cytokine administration, we demonstrate the induction of inflammation measured by changes in barrier function and cytokine secretion. These states of inflammation are induced at various time points within a stable culture window, providing a robust platform for evaluation of therapeutic agents. These data reveal that the administration of specific small molecule inhibitors mitigates the inflammatory response and enables tissue recovery, providing an opportunity for identification of new therapeutic targets for gum disease with the potential to facilitate relevant preclinical drug efficacy and toxicity testing.

The Influence of Rural Healthcare Systems and Communities on Surgery and Recovery: A Qualitative Study.

INTRODUCTION: Successful recovery after surgery is complex and highly individual. Rural patients encounter greater barriers to successful surgical recovery than urban patients due to varying healthcare and community factors. Although studies have previously examined the recovery process, rural patients' experiences with recovery have not been well-studied. The rural socioecological context can provide insights into potential barriers or facilitators to rural patient recovery after surgery. METHODS: We conducted semi-structured qualitative interviews with a purposeful sample of 30 adult general surgery patients from rural areas in the Mountain West region of the United States. We used the socioecological framework to analyze their responses. Interviews focused on rural participants' experiences accessing healthcare and the impact of family and community support during postoperative recovery. Interviews were transcribed verbatim and coded using content and thematic analysis. RESULTS: All participants commented on the quality of their rural healthcare systems and its influence on postoperative care. Some enjoyed the trust developed through long-standing relationships with providers in their communities. However, participants described community providers' lack of money, equipment, and/or knowledge as barriers to care. Following surgery, participants recognized that there are advantages and disadvantages to receiving family and community support. Some participants worried about being stigmatized or judged by their community. CONCLUSIONS: Future interventions aimed at improving access to and recovery from surgery for rural patients should take into account the unique perspectives of rural patients. Addressing the socioecological factors surrounding rural surgery patients, such as healthcare, family, and community resources, will be key to improving postoperative recovery.

Versican secreted by the ovary links ovulation and migration in fallopian tube derived serous cancer.

High grade serous ovarian cancers (HGSOC) predominantly arise in the fallopian tube epithelium (FTE) and colonize the ovary first, before further metastasis to the peritoneum. Ovarian cancer risk is directly related to the number of ovulations, suggesting that the ovary may secrete specific factors that act as chemoattractants for fallopian tube derived tumor cells during ovulation. We found that 3D ovarian organ culture produced a secreted factor that enhanced the migration of FTE non-tumorigenic cells as well as cells harboring specific pathway modifications commonly found in high grade serous cancers. Through size fractionation and a small molecule inhibitors screen, the secreted protein was determined to be 50-100kDa in size and acted through the Epidermal Growth Factor Receptor (EGFR). To correlate the candidates with ovulation, the PREDICT organ-on-chip system was optimized to support ovulation in a perfused microfluidic platform. Versican was found in the correct molecular weight range, contained EGF-like domains, and correlated with ovulation in the PREDICT system. Exogenous versican increased migration, invasion, and enhanced adhesion of both murine and human FTE cells to the ovary in an EGFR-dependent manner. The identification of a protein secreted during ovulation that impacts the ability of FTE cells to colonize the ovary provides new insights into the development of strategies for limiting primary ovarian metastasis.

Use of post-discharge opioid consumption patterns as a tool for evaluating opioid prescribing guidelines.

BACKGROUND: Leftover pills from postoperative opioid prescriptions place patients and members of their communities at risk for opioid misuse. We aimed to better understand patients' post-discharge opioid consumption patterns to inform new methods of postoperative opioid prescribing. METHODS: We assessed post-discharge opioid consumption of general surgery patients and assessed the adequacy of discharge opioid prescriptions. We then compared patient opioid consumption to a number of theoretical discharge prescriptions based on different opioid prescribing guidelines and a proposed discharge prescription based on the metric 24-h pre-discharge opioid consumption (PDOC). RESULTS: 62/99 patients (62.6%) returned an opioid log book. Median 24-h PDOC was 22.5 MME (IQR 5.0-45.0) and median discharge prescription size was 15 pills (IQR:10-20). Prescriptions were adequate for 83.7% of patients. The median number of pills used was 3 (IQR:0-11) and median time to opioid cessation was 3 days (IQR:0-5). Actual prescriptions were consistent with national opioid prescribing guidelines. Prescriptions based on the formula 2 × 24-h PDOC would have decreased the number of leftover pills by 7.5 per patient. CONCLUSIONS: Despite prescribing opioids consistent with national opioid prescribing guidelines, patients still receive too many pills. Improved opioid prescribing could be accomplished by use of the formula 2 × 24-h PDOC.

Socioeconomic disadvantage is associated with greater mortality after high-risk emergency general surgery.

BACKGROUND: Socioeconomic disadvantage is associated with worse outcomes after elective surgery, but the effect on emergency general surgery (EGS) remains unclear. We examined the association of socioeconomic disadvantage and outcomes after EGS procedures and investigated whether admission to hospitals with comprehensive clinical and social resources mitigated this effect. METHODS: Adults undergoing 1 of the 10 most burdensome high- and low-risk EGS procedures were identified in six 2014 State Inpatient Databases. Socioeconomic disadvantage was assessed using Area Deprivation Index (ADI) of patient residence. Multivariable logistic regression models adjusting for patient and hospital factors were used to evaluate the association between ADI quartile (high >75 percentile vs. low <25 percentile), and 30-day readmission, in-hospital mortality, and discharge disposition. Effect modification between ADI and (a) level 1 trauma center and (b) safety-net hospital status was tested. RESULTS: A total of 103,749 patients were analyzed: 72,711 low-risk (70.1%) and 31,038 high-risk procedures (29.9%). Patients from neighborhoods with high socioeconomic disadvantage had a higher proportion with ≥3 comorbidities (41.9% vs. 32.0%), minority race/ethnicity (66.3% vs. 42.4%), and Medicaid (28.8% vs. 14.7%) and were less likely to be treated at level 1 trauma centers (18.3% vs. 27.7%; p < 0.001 for all). Adjusting for competing factors, high socioeconomic disadvantage was associated with increased in-hospital mortality after high-risk procedures (odd ratio, 1.30; 95% confidence interval, 1.01-1.66; p = 0.04) and higher odds of non-home discharge (odd ratio, 1.15; 95% confidence interval, 1.02-1.30; p = 0.03) for low-risk procedures. Socioeconomic disadvantage was not associated with 30-day readmission for either procedure group. Level 1 trauma status and safety-net hospital did not meaningfully mitigate effect of ADI for any outcome. CONCLUSION: Socioeconomic disadvantage is associated with increased mortality after high-risk procedures and higher odds of non-home discharge after low-risk procedures. This effect was not mitigated by either level 1 trauma or safety-net hospitals. Interventions that specifically address the needs of socially vulnerable communities will be required to significantly improve EGS outcomes for this population. LEVEL OF EVIDENCE: Prognostic and Epidemiologic, level III.

Benign Colonic Strictures.

CASE SUMMARY: A 46-year-old man with no significant medical or surgical history presented to the emergency department with a 1-week history of worsening constipation, abdominal distension, nausea, and nonbloody, nonbilious emesis. Workup included a CT scan that was notable for a 5.3 × 3.9 cm "apple core-type" mass located within the sigmoid colon with proximal large-bowel dilation. Carcinoembryonic antigen was 1.4. No metastatic disease was seen on chest, abdominal, or pelvic CT scans. Flexible sigmoidoscopy identified a sigmoid colon mass 30 cm from the anal verge with near complete obstruction. Biopsies of the mass did not show evidence of dysplasia or malignancy. The Gastroenterology service declined to place a stent without a malignancy diagnosis. The patient subsequently underwent exploratory laparotomy, sigmoid colectomy, and end colostomy. Recovery was uneventful. Final pathology showed diverticulitis with abscess formation and no evidence of malignancy. A completion colonoscopy was unremarkable, and the patient underwent colostomy reversal 3 months later.

A high-throughput microfluidic bilayer co-culture platform to study endothelial-pericyte interactions.

Microphysiological organ-on-chip models offer the potential to improve the prediction of drug safety and efficacy through recapitulation of human physiological responses. The importance of including multiple cell types within tissue models has been well documented. However, the study of cell interactions in vitro can be limited by complexity of the tissue model and throughput of current culture systems. Here, we describe the development of a co-culture microvascular model and relevant assays in a high-throughput thermoplastic organ-on-chip platform, PREDICT96. The system consists of 96 arrayed bilayer microfluidic devices containing retinal microvascular endothelial cells and pericytes cultured on opposing sides of a microporous membrane. Compatibility of the PREDICT96 platform with a variety of quantifiable and scalable assays, including macromolecular permeability, image-based screening, Luminex, and qPCR, is demonstrated. In addition, the bilayer design of the devices allows for channel- or cell type-specific readouts, such as cytokine profiles and gene expression. The microvascular model was responsive to perturbations including barrier disruption, inflammatory stimulation, and fluid shear stress, and our results corroborated the improved robustness of co-culture over endothelial mono-cultures. We anticipate the PREDICT96 platform and adapted assays will be suitable for other complex tissues, including applications to disease models and drug discovery.

Correction: A high-throughput microfluidic microphysiological system (PREDICT-96) to recapitulate hepatocyte function in dynamic, re-circulating flow conditions.

Correction for 'A high-throughput microfluidic microphysiological system (PREDICT-96) to recapitulate hepatocyte function in dynamic, re-circulating flow conditions' by Kelly Tan et al., Lab Chip, 2019, 19, 1556-1566, DOI: .

Knockout of the circadian clock protein PER1 results in sex-dependent alterations of ET-1 production in mice in response to a high-salt diet plus mineralocorticoid treatment.

Previously, we showed that global knockout (KO) of the circadian clock transcription factor PER1 in male, but not female, mice fed a high-salt diet plus mineralocorticoid treatment (HS/DOCP) resulted in nondipping hypertension and decreased night/day ratio of sodium (Na) excretion. Additionally, we have shown that the endothelin-1 (ET-1) gene is targeted by both PER1 and aldosterone. We hypothesized that ET-1 would exhibit a sex-specific response to HS/DOCP treatment in PER1 KO. Here we show that male, but not female, global PER1 KO mice exhibit a decreased night/day ratio of urinary ET-1. Gene expression analysis revealed significant genotype differences in ET-1 and endothelin A receptor (ETA) expression in male, but not female, mice in response to HS/DOCP. Additionally, both wild-type and global PER1 KO male mice significantly increase endothelin B receptor (ETB) expression in response to HS/DOCP, but female mice do not. Finally, siRNA-mediated knockdown of PER1 in mouse cortical collecting duct cells (mpkCCDc14) resulted in increased ET-1 mRNA expression and peptide secretion in response to aldosterone treatment. These data suggest that PER1 is a negative regulator of ET-1 expression in response to HS/DOCP, revealing a novel mechanism for the regulation of renal Na handling in response to HS/DOCP treatment.

EDN1-AS, A Novel Long Non-coding RNA Regulating Endothelin-1 in Human Proximal Tubule Cells.

Endothelin-1 (ET-1) is a peptide hormone that functions as a vasoconstrictor in the vasculature, whereas in the collecting duct of the kidney it exerts blood pressure-lowering effects via natriuretic actions. Aberrant ET-1 signaling is associated with several pathological states including hypertension and chronic kidney disease. ET-1 expression is regulated largely through transcriptional control of the gene that encodes ET-1, EDN1. Here we report a long, non-coding RNA (lncRNA) that appears to be antisense to the EDN1 gene, called EDN1-AS. Because EDN1-AS represents a potential novel mechanism to regulate ET-1 expression, we examined the regulation of EDN1-AS expression and action. A putative glucocorticoid receptor response (GR) element upstream of the predicted EDN1-AS transcription start site was identified using the ENCODE database and the UCSC genome browser. Two homozygous deletion clones of the element were generated using CRISPR/Cas9. This deletion resulted in a significant increase in the expression of EDN1-AS, which was associated with increased secretion of ET-1 peptide from HK-2 cells (two-fold increase in KO cells vs. CNTL, n = 7, P < 0.05). Phenotypic characterization of these CRISPR clones revealed a difference in cell growth rates. Using a standard growth assay, we determined that the KO1 clone exhibited a three-fold increase in growth over 8 days compared to control cells (n = 4, P < 0.01) and the KO2 clone exhibited a two-fold increase (n = 4, P < 0.01). These results support a role for EDN1-AS as a novel regulatory mechanism of ET-1 expression and cellular proliferation.

A thermoplastic microfluidic microphysiological system to recapitulate hepatic function and multicellular interactions.

Hepatic in vitro platforms ranging from multi-well cultures to bioreactors and microscale systems have been developed as tools to recapitulate cellular function and responses to aid in drug screening and disease model development. Recent developments in microfabrication techniques and cellular materials enabled fabrication of next-generation, advanced microphysiological systems (MPSs) that aim to capture the cellular complexity and dynamic nature of the organ presenting highly controlled extracellular cues to cells in a physiologically relevant context. Historically, MPSs have heavily relied on elastomeric materials in their manufacture, with unfavorable material characteristics (such as lack of structural rigidity) limiting their use in high-throughput systems. Herein, we aim to create a microfluidic bilayer model (microfluidic MPS) using thermoplastic materials to allow hepatic cell stabilization and culture, retaining hepatic functional phenotype and capturing cellular interactions. The microfluidic MPS consists of two overlapping microfluidic channels separated by a porous tissue-culture membrane that acts as a surface for cellular attachment and nutrient exchange; and an oxygen permeable material to stabilize and sustain primary human hepatocyte (PHH) culture. Within the microfluidic MPS, PHHs are cultured in the top channel in a collagen sandwich gel format with media exchange accomplished through the bottom channel. We demonstrate PHH culture for 7 days, exhibiting measures of hepatocyte stabilization, secretory and metabolic functions. In addition, the microfluidic MPS dimensions provide a reduced media-to-cell ratio in comparison with multi-well tissue culture systems, minimizing dilution and enabling capture of cellular interactions and responses in a hepatocyte-Kupffer coculture model under an inflammatory stimulus. Utilization of thermoplastic materials in the model and ability to incorporate multiple hepatic cells within the system is our initial step towards the development of a thermoplastic-based high-throughput microfluidic MPS platform for hepatic culture. We envision the platform to find utility in development and interrogation of disease models of the liver, multi-cellular interactions and therapeutic responses.

Female C57BL/6J mice lacking the circadian clock protein PER1 are protected from nondipping hypertension.

The circadian clock is integral to the maintenance of daily rhythms of many physiological outputs, including blood pressure. Our laboratory has previously demonstrated the importance of the clock protein period 1 (PER1) in blood pressure regulation in male mice. Briefly, a high-salt diet (HS; 4% NaCl) plus injection with the long-acting mineralocorticoid deoxycorticosterone pivalate (DOCP) resulted in nondipping hypertension [<10% difference between night and day blood pressure (BP) in Per1-knockout (KO) mice but not in wild-type (WT) mice]. To date, there have been no studies that have examined the effect of a core circadian gene KO on BP rhythms in female mice. The goal of the present study was to determine whether female Per1-KO mice develop nondipping hypertension in response to HS/DOCP treatment. For the first time, we demonstrate that loss of the circadian clock protein PER1 in female mice does not significantly change mean arterial pressure (MAP) or the BP rhythm relative to female C57BL/6 WT control mice. Both WT and Per1-KO female mice experienced a significant increase in MAP in response to HS/DOCP. Importantly, however, both genotypes maintained a >10% dip in BP on HS/DOCP. This effect is distinct from the nondipping hypertension seen in male Per1-KO mice, demonstrating that the female sex appears to be protective against PER1-mediated nondipping hypertension in response to HS/DOCP. Together, these data suggest that PER1 acts in a sex-dependent manner in the regulation of cardiovascular rhythms.

Repair of Enlarging Left Ventricular Pseudoaneurysm Two Months After Coronary Artery Bypass Grafting.

Enlarging left ventricular pseudoaneurysms are a rare complication (especially after surgical revascularization) and require tailored surgical decision making and techniques for repair. We present a challenging patient with a rapidly enlarging left ventricular pseudoaneurysm 4 weeks after coronary bypass. The repair was approached through a left thoracotomy using circulatory arrest with selective antegrade cerebral perfusion.

Renal Na-handling defect associated with PER1-dependent nondipping hypertension in male mice.

Many physiological functions have a circadian rhythm, including blood pressure (BP). BP is highest during the active phase, whereas during the rest period, BP dips 10-20%. Patients that do not experience this dip at night are termed "nondippers." Nondipping hypertension is associated with increased risk of cardiovascular disease. The mechanisms underlying nondipping hypertension are not understood. Without the circadian clock gene Per1, C57BL/6J mice develop nondipping hypertension on a high-salt diet plus mineralocorticoid treatment (HS/DOCP). Our laboratory has shown that PER1 regulates expression of several genes related to sodium (Na) transport in the kidney, including epithelial Na channel (ENaC) and Na chloride cotransporter (NCC). Urinary Na excretion also demonstrates a circadian pattern with a peak during active periods. We hypothesized that PER1 contributes to circadian regulation of BP via a renal Na-handling-dependent mechanism. Na-handling genes from the distal nephron were inappropriately regulated in KO mice on HS/DOCP. Additionally, the night/day ratio of Na urinary excretion by Per1 KO mice is decreased compared with WT (4 × vs. 7×, P < 0.001, n = 6 per group). Distal nephron-specific Per1 KO mice also show an inappropriate increase in expression of Na transporter genes αENaC and NCC. These results support the hypothesis that PER1 mediates control of circadian BP rhythms via the regulation of distal nephron Na transport genes. These findings have implications for the understanding of the etiology of nondipping hypertension and the subsequent development of novel therapies for this dangerous pathophysiological condition.