Rapid Critical Care Training for Nurses Deployed to Intensive Care Units During the COVID-19 Surge.

BACKGROUND: During the first COVID-19 pandemic wave, non-intensive care unit (non-ICU) nurses were deployed to temporary ICUs to provide critical care for the patient surge. A rapid critical care training program was designed to prepare them to care for patients in either temporary or permanent ICUs. OBJECTIVE: To evaluate the effectiveness of this training program in preparing non-ICU nurses to provide critical care for COVID-19 patients in temporary ICUs. METHODS: A survey was used to evaluate the impact of rapid critical care training on nurses' critical care skills and compare the experiences of nurses deployed to temporary versus permanent ICUs. Data were analyzed with χ2 and Spearman ρ tests with α = .05. RESULTS: Compared with nurses in other locations, nurses deployed to temporary ICUs were less likely to report improved capability in managing mechanical ventilation; infusions of sedative, vasoactive, and paralytic agents; and continuous renal replacement therapy. Nurses in temporary ICUs also reported being less prepared to care for critically ill patients (all P < .05). CONCLUSIONS: The rapid training program provided basic critical care knowledge for nurses in temporary ICUs, but experiences differed significantly between those deployed to temporary versus permanent ICUs. Although participants believed they provided safe care, nurses with no critical care experience cannot be expected to learn comprehensive critical care from expedited instruction; more formal clinical support is needed for nurses in temporary ICUs. Rapid critical care training can meet emergency needs for nurses capable of providing critical care.

T helper 1 effector memory CD4+ T cells protect the skin from poxvirus infection.

Poxvirus infections of the skin are a recent emerging public health concern, yet the mechanisms that mediate protective immunity against these viral infections remain largely unknown. Here, we show that T helper 1 (Th1) memory CD4+ T cells are necessary and sufficient to provide complete and broad protection against poxvirus skin infections, whereas memory CD8+ T cells are dispensable. Core 2 O-glycan-synthesizing Th1 effector memory CD4+ T cells rapidly infiltrate the poxvirus-infected skin microenvironment and produce interferon γ (IFNγ) in an antigen-dependent manner, causing global changes in gene expression to promote anti-viral immunity. Keratinocytes express IFN-stimulated genes, upregulate both major histocompatibility complex (MHC) class I and MHC class II antigen presentation in an IFNγ-dependent manner, and require IFNγ receptor (IFNγR) signaling and MHC class II expression for memory CD4+ T cells to protect the skin from poxvirus infection. Thus, Th1 effector memory CD4+ T cells exhibit potent anti-viral activity within the skin, and keratinocytes are the key targets of IFNγ necessary for preventing poxvirus infection of the epidermis.

Supervised learning of high-confidence phenotypic subpopulations from single-cell data.

Accurately identifying phenotype-relevant cell subsets from heterogeneous cell populations is crucial for delineating the underlying mechanisms driving biological or clinical phenotypes. Here, by deploying a learning with rejection strategy, we developed a novel supervised learning framework called PENCIL to identify subpopulations associated with categorical or continuous phenotypes from single-cell data. By embedding a feature selection function into this flexible framework, for the first time, we were able to select informative features and identify cell subpopulations simultaneously, which enables the accurate identification of phenotypic subpopulations otherwise missed by methods incapable of concurrent gene selection. Furthermore, the regression mode of PENCIL presents a novel ability for supervised phenotypic trajectory learning of subpopulations from single-cell data. We conducted comprehensive simulations to evaluate PENCILs versatility in simultaneous gene selection, subpopulation identification and phenotypic trajectory prediction. PENCIL is fast and scalable to analyze 1 million cells within 1 hour. Using the classification mode, PENCIL detected T-cell subpopulations associated with melanoma immunotherapy outcomes. Moreover, when applied to scRNA-seq of a mantle cell lymphoma patient with drug treatment across multiple time points, the regression mode of PENCIL revealed a transcriptional treatment response trajectory. Collectively, our work introduces a scalable and flexible infrastructure to accurately identify phenotype-associated subpopulations from single-cell data.

Improving Communication and Response to Clinical Deterioration to Increase Patient Safety in the Intensive Care Unit.

BACKGROUND: In the critical care setting, early recognition of clinical decompensation is imperative to trigger prompt intervention and optimize patient outcomes. LOCAL PROBLEM: In a 20-bed surgical intensive care unit of an urban academic medical center, cases of clinical deterioration that highlighted opportunities to improve the communication process prompted a reassessment of health care provider roles and responsibilities. METHODS: A quality improvement initiative was implemented to enhance communication among intensive care unit clinical staff members, improve the timeliness of reporting clinical deterioration, and ensure implementation of timely, appropriate interventions to eliminate adverse outcomes. INTERVENTIONS: Nurses were surveyed to determine their perceptions of communication and collaboration among providers. Education was provided that focused on familiarizing nurses with clinical conditions necessitating direct notification of the attending surgical intensivist and included review of a case in which escalation of care did not occur. Multidisciplinary rounds were expanded to engage night-shift nurses in clinical discussions and decision-making. A template was created to document episodes of escalation in the electronic health record. RESULTS: Since implementation of the quality improvement interventions, no incidents of patient harm or death related to failure to escalate have occurred to date. A total of 16 episodes of escalation for clinical deterioration were documented in the electronic health record. Most nurses reported an increased level of confidence in understanding when to escalate concerns about clinical deterioration. CONCLUSION: Implementing a multimodal program to empower nurses to escalate clinical concerns directly to the attending physician eliminated adverse events related to failure to escalate.

Trajectories of Neurologic Recovery 12 Months After Hospitalization for COVID-19: A Prospective Longitudinal Study.

BACKGROUND AND OBJECTIVE: Little is known about trajectories of recovery 12 months after hospitalization for severe COVID-19. METHODS: We conducted a prospective, longitudinal cohort study of patients with and without neurologic complications during index hospitalization for COVID-19 from March 10, 2020, to May 20, 2020. Phone follow-up batteries were performed at 6 and 12 months after COVID-19 onset. The primary 12-month outcome was the modified Rankin Scale (mRS) score comparing patients with or without neurologic complications using multivariable ordinal analysis. Secondary outcomes included activities of daily living (Barthel Index), telephone Montreal Cognitive Assessment (t-MoCA), and Quality of Life in Neurologic Disorders (Neuro-QoL) batteries for anxiety, depression, fatigue, and sleep. Changes in outcome scores from 6 to 12 months were compared using nonparametric paired-samples sign test. RESULTS: Twelve-month follow-up was completed in 242 patients (median age 65 years, 64% male, 34% intubated during hospitalization) and 174 completed both 6- and 12-month follow-up. At 12 months, 197/227 (87%) had ≥1 abnormal metric: mRS >0 (75%), Barthel Index <100 (64%), t-MoCA ≤18 (50%), high anxiety (7%), depression (4%), fatigue (9%), or poor sleep (10%). Twelve-month mRS scores did not differ significantly among those with (n = 113) or without (n = 129) neurologic complications during hospitalization after adjusting for age, sex, race, pre-COVID-19 mRS, and intubation status (adjusted OR 1.4, 95% CI 0.8-2.5), although those with neurologic complications had higher fatigue scores (T score 47 vs 44; p = 0.037). Significant improvements in outcome trajectories from 6 to 12 months were observed in t-MoCA scores (56% improved, median difference 1 point; p = 0.002) and Neuro-QoL anxiety scores (45% improved; p = 0.003). Nonsignificant improvements occurred in fatigue, sleep, and depression scores in 48%, 48%, and 38% of patients, respectively. Barthel Index and mRS scores remained unchanged between 6 and 12 months in >50% of patients. DISCUSSION: At 12 months after hospitalization for severe COVID-19, 87% of patients had ongoing abnormalities in functional, cognitive, or Neuro-QoL metrics and abnormal cognition persisted in 50% of patients without a history of dementia/cognitive abnormality. Only fatigue severity differed significantly between patients with or without neurologic complications during index hospitalization. However, significant improvements in cognitive (t-MoCA) and anxiety (Neuro-QoL) scores occurred in 56% and 45% of patients, respectively, between 6 and 12 months. These results may not be generalizable to those with mild or moderate COVID-19.

Skin Failure Among Critically Ill Patients Afflicted with Coronavirus Disease 2019 (COVID-19).

Objective: To characterize skin integrity among coronavirus disease 2019 (COVID-19) patients treated in the intensive care unit (ICU), and identify risk factors for skin failure (SF) in these patients. Design: The characteristic, profound pro-inflammatory, hypercoagulable state of COVID-19 is manifested by the high severity of illness and extensive organ dysfunction observed in these patients. SF in critically ill patients, although described previously, exhibits a uniquely complex pathogenesis in this population. Patients: Retrospective review of all COVID-19 patients (confirmed positive for severe acute respiratory syndrome coronavirus-2 [SARS-CoV-2]) admitted to a single surgical ICU for at least 48 hours between March-June 2020. Interventions: Data were extracted from a COVID-19 institutional data repository that harvested data from electronic health records and other clinical data sources. Demographics; coagulation/inflammation biomarkers; number, location, and stage of SF lesions; resource utilization; and outcomes were captured. Measurements and Main Results: 64 patients met inclusion criteria; 51 (80%) developed SF (SF+ ). Forty-three (85%) developed stage 3 or higher SF (χ2 = 22.66, P < .0001). Thirty-nine of 51 (76%) SF+ patients developed more than one SF lesion (χ2 = 13.26, P = .0003). SF+ patients manifested a profound pro-inflammatory, hypercoagulable phenotype (lower serum albumin and higher ferritin, interleukin [IL]-6 and D-dimer concentrations [all, P < .001]). Durations of mechanical ventilation, vasopressor therapy, and ICU length of stay were significantly longer (all, P < .05) in the SF + patients. Conclusions: The unique characteristics of COVID-19 dermatopathology and the strong correlation between markers of inflammation and development of SF reflect COVID-19-related organ dysfunction and its deleterious effects on the microcirculation. Considering that skin is invaded directly by SARS-CoV-2 and affected by COVID-19-related immune complex deposition and microthrombosis, SF may reflect disease as opposed to pressure injuries related to processes of care. In the context of COVID-19 critical illness, SF should not be considered a "never event."

Predicting Fraud Victimization Using Classical Machine Learning.

Protecting financial consumers from investment fraud has been a recurring problem in Canada. The purpose of this paper is to predict the demographic characteristics of investors who are likely to be victims of investment fraud. Data for this paper came from the Investment Industry Regulatory Organization of Canada's (IIROC) database between January of 2009 and December of 2019. In total, 4575 investors were coded as victims of investment fraud. The study employed a machine-learning algorithm to predict the probability of fraud victimization. The machine learning model deployed in this paper predicted the typical demographic profile of fraud victims as investors who classify as female, have poor financial knowledge, know the advisor from the past, and are retired. Investors who are characterized as having limited financial literacy but a long-time relationship with their advisor have reduced probabilities of being victimized. However, male investors with low or moderate-level investment knowledge were more likely to be preyed upon by their investment advisors. While not statistically significant, older adults, in general, are at greater risk of being victimized. The findings from this paper can be used by Canadian self-regulatory organizations and securities commissions to inform their investors' protection mandates.

Stop the Bleed: Effective Training in Need of Improvement.

BACKGROUND: The "Stop the Bleed" (StB) campaign aims to educate laypersons on performing bleeding control techniques in any setting that requires hemorrhage control, such as motor vehicle crashes or mass casualty incidents. Participants undergo a didactic and practical session, the latter incorporating a mannequin. We hypothesized that participants would increase content knowledge after StB participation and that the training could be improved by a more life-like bleeding modification of the mannequin. MATERIALS AND METHODS: From July 2017 to January 2018, hospital and community members from a major metropolitan area participated in StB training. Participants provided demographic data regarding prior emergency training and were asked pre- and post-test questions (five-point Likert scale) regarding their response to hemorrhage. Individuals also evaluated the mannequin on bleeding simulation. Scores were reported as means with standard deviation or medians with interquartile ranges (IQRs) with subset analysis stratified by experience. RESULTS: Of 402 participants, 310 provided complete data. On the composite, pre-test self-assessment, participants had a median score of 24 of 30 points (IQR 16-30). Post-testing demonstrated a statistically significant increase with a median score of 29 (IQR 25-30, P < 0.05). Subset analysis by prior emergency training (n = 102) demonstrated that both those with prior emergency training and those with no prior emergency training had significant improvement. On evaluation of the mannequin, participants reported that a more realistic model would increase their confidence in technique. Both subgroups reported that training would be enhanced if the mannequins were more realistic. CONCLUSIONS: StB is an effective education program. Those without prior experience or training in hemorrhage cessation demonstrated the most improvement. Regardless of background, participants reported overwhelmingly that the training would be more effective if it were more realistic. Future work to design and develop cost-effective mannequins demonstrating pulsatile blood flow and cessation of hemorrhage could enable learners to actually "Stop the Bleed".

Rapid Critical Care Training of Nurses in the Surge Response to the Coronavirus Pandemic.

BACKGROUND: In response to the coronavirus pandemic, New York State mandated that all hospitals double the capacity of their adult intensive care units In this facility, resources were mobilized to increase from 104 to 283 beds. OBJECTIVE: To create and implement a 3-hour curriculum to prepare several hundred non-critical care staff nurses to manage critically ill patients with coronavirus disease 2019. METHODS: Critical care nursing leaders and staff developed and implemented a flexible critical care nursing curriculum tailored to the diverse experience, expertise, and learning needs of non-critical care nursing staff who were being redeployed to critical care units during the surge response to the pandemic. Curricular elements included respiratory failure and ventilator management, shock and hemodynamics, pharmacotherapy for critical illnesses, and renal replacement therapy. A skills station allowed hands-on practice with common critical care equipment. RESULTS: A total of 413 nurses completed training within 10 days. As of June 2020, 151 patients with coronavirus disease 2019 still required mechanical ventilation at our institution, and 7 of 10 temporary intensive care units remained operational. Thus most of the nurses who received this training continued to practice critical care. A unique feature of this curriculum was the tailored instruction, adapted to learners' needs, which improved the efficiency of content delivery. CONCLUSIONS: Program evaluation is ongoing. As recovery and restoration proceed and normal operations resume, detailed feedback from program participants and patient care managers will help the institution maintain high operational readiness should a second wave of critically ill patients with coronavirus disease 2019 be admitted.

Trauma Response Nurse: Bringing Critical Care Experience and Continuity to Early Trauma Care.

Multitrauma patients can benefit significantly from specialized care. Prior to mid-2016, this hospital's trauma team did not include a surgical intensive care unit (SICU) nurse. As the value of bringing this expertise to the patient upon arrival was realized, the role of the trauma response nurse (TRN) was developed. The TRN role was designed to provide a dedicated SICU nurse to care for trauma patients from emergency department (ED) arrival through disposition. The integration of the TRN role into the trauma team sought to improve quality and safety, as well as communication and collaboration, and enhance continuity of care. The primary responsibilities of the TRN were to assist with clinical interventions, transport patients fromthe ED to tests and procedures, and assume care through disposition. Additional TRN duties included education, community outreach, and performance improvement. TRNs now respond to all trauma activations that occur on weekday day shift. This role has improved collaboration between nursing disciplines, improved the overall function of the trauma team, and enhanced the safety of trauma patients during transport. TRNs make valuable contributions to the education and outreach missions of the trauma program and ensure that patients are receiving the highest level of trauma care.

World trauma education: hemorrhage control training for healthcare providers in India.

BACKGROUND: Hemorrhage remains a major cause of death around the world. Eighty percent of trauma patients in India do not receive medical care within the first hour. The etiology of these poor outcomes is multifactorial. We describe findings from the first Stop the Bleed (StB) course recently offered to a group of medical providers in southern India. METHODS: A cross-sectional survey of 101 participants who attended StB trainings in India was performed. Pre-training and post-training questionnaires were collected from each participant. In total, 88 healthcare providers' responses were analyzed. Three bleeding control skills were presented: wound compression, wound packing, and tourniquet application. RESULTS: Among participants, only 23.9% had received prior bleeding control training. Participants who reported feeling 'extremely confident' responding to an emergency medical situation rose from 68.2% prior to StB training to 94.3% post-training. Regarding hemorrhage control abilities, 37.5% felt extremely confident before the training, compared with 95.5% after the training. For wound packing and tourniquet application, 44.3% and 53.4%, respectively, felt extremely confident pre-training, followed by 97.7% for both skills post-training. Importantly, 90.9% of StB trainees felt comfortable teaching newly acquired hemorrhage control skills. A significant majority of participants said that confidence in their wound packing and tourniquet skills would improve with more realistic mannequins. CONCLUSION: To our knowledge, this is the first StB training in India. Disparities in access to care, long transport times, and insufficient numbers of prehospital personnel contribute to its significant trauma burden. Dissemination of these critical life-saving skills into this region and the resulting civilian interventions will increase the number of trauma patients who survive long enough to reach a trauma center. Additionally, considerations should be given to translating the course into local languages to increase program reach. LEVEL OF EVIDENCE: Level IV.

Selective targeting of lysyl oxidase-like 2 (LOXL2) suppresses hepatic fibrosis progression and accelerates its reversal.

BACKGROUND/AIMS: We studied the role of lysyl oxidase-like 2 (LOXL2) in collagen crosslinking and hepatic progenitor cell (HPC) differentiation, and the therapeutic efficacy of a LOXL2-blocking monoclonal antibody on liver fibrosis progression/reversal in mice. METHODS: Anti-LOXL2 antibody, control antilysyl oxidase antibody or placebo was administered during thioacetamide (TAA)-induced fibrosis progression or during recovery. Therapeutic efficacy in biliary fibrosis was tested in BALB/c.Mdr2-/- and 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-fed mice. Collagen crosslinking, fibrosis progression and reversal were assessed histologically and biochemically. HPC differentiation was studied in primary EpCAM(+) liver cells in vitro. RESULTS: LOXL2 was virtually absent from healthy but strongly induced in fibrotic liver, with predominant localisation within fibrotic septa. Delayed anti-LOXL2 treatment of active TAA fibrosis significantly reduced collagen crosslinking and histological signs of bridging fibrosis, with a 53% reduction in morphometric collagen deposition. In established TAA fibrosis, LOXL2 inhibition promoted fibrosis reversal, with enhanced splitting and thinning of fibrotic septa, and a 45% decrease in collagen area at 4 weeks of recovery. In the Mdr2-/- and DDC-induced models of biliary fibrosis, anti-LOXL2 antibody similarly achieved significant antifibrotic efficacy and suppressed the ductular reaction, while hepatocyte replication increased. Blocking LOXL2 had a profound direct effect on primary EpCAM(+) HPC behaviour in vitro, promoting their differentiation towards hepatocytes, while inhibiting ductal cell lineage commitment. CONCLUSIONS: LOXL2 mediates collagen crosslinking and fibrotic matrix stabilisation during liver fibrosis, and independently promotes fibrogenic HPC differentiation. By blocking these two convergent profibrotic pathways, therapeutic LOXL2 inhibition attenuates both parenchymal and biliary fibrosis and promotes fibrosis reversal.

The ectonucleotidase ENTPD1/CD39 limits biliary injury and fibrosis in mouse models of sclerosing cholangitis.

The pathogenesis of primary sclerosing cholangitis (PSC) and the mechanistic link to inflammatory bowel disease remain ill-defined. Ectonucleoside triphosphate diphosphohydrolase-1 (ENTPD1)/clusters of differentiation (CD) 39, the dominant purinergic ecto-enzyme, modulates intestinal inflammation. Here, we have explored the role of CD39 in biliary injury and fibrosis. The impact of CD39 deletion on disease severity was studied in multidrug resistance protein 2 (Mdr2)-/- and 3,5-diethoxycarbonyl-1,4-dihydrocollidine mouse models of sclerosing cholangitis and biliary fibrosis. Antibody-mediated CD8+ T-cell depletion, selective gut decontamination, experimental colitis, and administration of stable adenosine triphosphate (ATP) agonist were performed. Retinoic acid-induced gut imprinting on T cells was studied in vitro. Over half of Mdr2-/-;CD39-/- double mutants, expected by Mendelian genetics, died in utero. Compared to Mdr2-/-;CD39+/+, surviving Mdr2-/-;CD39-/- mice demonstrated exacerbated liver injury, fibrosis, and ductular reaction. CD39 deficiency led to a selective increase in hepatic CD8+ T cells and integrin α4ß7, a T-cell gut-tropism receptor. CD8+ cell depletion in Mdr2-/-;CD39-/- mice diminished hepatobiliary injury and fibrosis. Treatment with antibiotics attenuated, whereas dextran sulfate sodium-induced colitis exacerbated, liver fibrosis in Mdr2-/- mice. Colonic administration of αß-ATP into CD39-sufficient Mdr2-/- mice triggered hepatic CD8+ cell influx and recapitulated the severe phenotype observed in Mdr2-/-;CD39-/- mice. In vitro, addition of ATP promoted the retinoic acid-induced imprinting of gut-homing integrin α4ß7 on naive CD8+ cells. CD39 expression was relatively low in human normal or PSC livers but abundantly present on immune cells of the colon and further up-regulated in samples of patients with inflammatory bowel disease. Conclusion: CD39 deletion promotes biliary injury and fibrosis through gut-imprinted CD8+ T cells. Pharmacological modulation of purinergic signaling may represent a promising approach for the treatment of PSC. (Hepatology Communications 2017;1:957-972).

Integrin αvß6 critically regulates hepatic progenitor cell function and promotes ductular reaction, fibrosis, and tumorigenesis.

UNLABELLED: Integrin αvß6 is rapidly up-regulated on cells of epithelial lineage during tissue injury, where one of its primary functions is activation of latent transforming growth factor beta 1 (TGFß1). In human liver cirrhosis, αvß6 is overexpressed by cells comprising the ductular reaction, and its inhibition suppresses experimental biliary fibrosis in rodents. Here, we show that αvß6 is expressed on the actively proliferating subset of hepatic progenitor cells and is required for their progenitor function in vivo and in vitro through integrin αvß6-dependent TGFß1 activation. Freshly isolated αvß6(+) liver cells demonstrate clonogenic potential and differentiate into cholangiocytes and functional hepatocytes in vitro, whereas colony formation by epithelial cell adhesion molecule-positive progenitor cells is blocked by αvß6-neutralizing antibody and in integrin beta 6-deficient cells. Inhibition of progenitors by anti-αvß6 antibody is recapitulated by TGFß1 neutralization and rescued by addition of bioactive TGFß1. Genetic disruption or selective targeting of αvß6 with 3G9 antibody potently inhibits progenitor cell responses in mouse models of chronic biliary injury and protects from liver fibrosis and tumorigenesis, two conditions clinically associated with exacerbated ductular reaction. CONCLUSION: These results suggest that αvß6 is a promising target for chronic fibrotic liver diseases and associated cancers.

Lysyl oxidase activity contributes to collagen stabilization during liver fibrosis progression and limits spontaneous fibrosis reversal in mice.

Collagen stabilization through irreversible cross-linking is thought to promote hepatic fibrosis progression and limit its reversibility. However, the mechanism of this process remains poorly defined. We studied the functional contribution of lysyl oxidase (LOX) to collagen stabilization and hepatic fibrosis progression/reversalin vivousing chronic administration of irreversible LOX inhibitor ß-aminopropionitrile (BAPN, or vehicle as control) in C57Bl/6J mice with carbon tetrachloride (CCl4)-induced fibrosis. Fibrotic matrix stability was directly assessed using a stepwise collagen extraction assay and fibrotic septae morphometry. Liver cells and fibrosis were studied by histologic, biochemical methods and quantitative real-time reverse-transcription PCR. During fibrosis progression, BAPN administration suppressed accumulation of cross-linked collagens, and fibrotic septae showed widening and collagen fibrils splitting, reminiscent of remodeling signs observed during fibrosis reversal. LOX inhibition attenuated hepatic stellate cell activation markers and promoted F4/80-positive scar-associated macrophage infiltration without an increase in liver injury. In reversal experiments, BAPN-treated fibrotic mice demonstrated accelerated fibrosis reversal after CCl4withdrawal. Our findings demonstrate for the first time that LOX contributes significantly to collagen stabilization in liver fibrosis, promotes fibrogenic activation of attenuated hepatic stellate cells, and limits fibrosis reversal. Our data support the concept of pharmacologic targeting of LOX pathway to inhibit liver fibrosis and promote its resolution.-Liu, S. B., Ikenaga, N., Peng, Z.-W., Sverdlov, D. Y., Greenstein, A., Smith, V., Schuppan, D., Popov, Y. Lysyl oxidase activity contributes to collagen stabilization during liver fibrosis progression and limits spontaneous fibrosis reversal in mice.

A new Mdr2(-/-) mouse model of sclerosing cholangitis with rapid fibrosis progression, early-onset portal hypertension, and liver cancer.

We previously characterized the Mdr2(Abcb4)(-/-) mouse as a reproducible model of chronic biliary liver disease. However, it demonstrates relatively slow fibrosis progression, possibly due to its fibrosis-resistant genetic background. We aimed to improve the model by moving it onto a fibrosis-susceptible background. We generated novel BALB/c.Mdr2(-/-) mouse via genetic backcross onto highly fibrosis-susceptible BALB/c substrain, identified in inbred mouse strain screening. Liver fibrosis, portal pressure, and hepatic tumor burden in BALB/c.Mdr2(-/-) mice were studied up to 1 year of age in direct comparison to parental strain FVB.Mdr2(-/-). BALB/c.Mdr2(-/-) mice developed periductular onion-skin type fibrotic lesions and pronounced ductular reaction starting from 4 weeks of age. Compared to parental strain, BALB/c.Mdr2(-/-) mice demonstrated dramatically accelerated liver fibrosis, with threefold increase in collagen deposition and bridging fibrosis/early signs of cirrhosis at 12 weeks. This was accompanied by early-onset severe portal hypertension and twofold to fourfold increase in profibrogenic transcripts Col1a1 [procollagen α1(I)], Tgfb1, and Timp1. Primary liver cancers in BALB/c.Mdr2(-/-) developed earlier, with greater tumor burden compared to FVB.Mdr2(-/-). BALB/c.Mdr2(-/-) mice have unprecedented degree and rapidity of hepatic fibrosis progression and clinically relevant cirrhosis complications, such as early-onset portal hypertension and primary liver cancers. This new model will facilitate development of antifibrotic drugs and studies into mechanisms of biliary fibrosis progression.

Extrahepatic platelet-derived growth factor-ß, delivered by platelets, promotes activation of hepatic stellate cells and biliary fibrosis in mice.

BACKGROUND & AIMS: Platelet-derived growth factor-ß (PDGFB) is a mitogen for hepatic stellate cells (HSCs). We studied the cellular sources of PDGFB and the effects of a high-affinity monoclonal antibody against PDGFB (MOR8457) in mouse models of biliary fibrosis. METHODS: Cellular sources of PDGFB were identified using quantitative reverse-transcription polymerase chain reaction, biochemical, and immunohistologic methods. Mice with advanced biliary fibrosis, MDR2(Abcb4)-null mice, and C57Bl/6 (control) mice were placed on 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-supplemented diets and were given weekly intraperitoneal injections of MOR8457. Platelets were depleted from MDR2-null mice by injection of an antibody against CD41, or inhibited with diets containing low-dose aspirin. Liver tissues were collected and analyzed by quantitative reverse-transcription PCR and histologic and biochemical analyses. RESULTS: Levels of PDGFB protein, but not messenger RNA, were increased in fibrotic livers of MDR2-null mice, compared with control mice. Platelet clusters were detected in the hepatic endothelium, in close proximity to HSCs, and were identified as a source of PDGFB protein in MDR2-null mice. Levels of the PDGFB were increased in serum samples from patients with early stages of liver fibrosis of various etiologies (F1-2, n = 16; P < .05), compared with nonfibrotic liver tissue (F0, n = 12). Depletion of platelets from MDR2-null mice normalized hepatic levels of PDGFB within 48 hours, reducing levels of a marker of HSC activation (α-smooth muscle actin) and expression of genes that promote fibrosis. Diets supplemented with low-dose aspirin reduced circulating serum and hepatic levels of PDGFB and significantly reduced progression of fibrosis in MDR2-null mice over 1 year. MOR8457 produced a dose-dependent decrease in liver fibrosis in MDR2-null mice, reducing collagen deposition by 45% and expression of fibrosis-associated genes by 50%, compared with mice given a control antibody. In vitro, platelets activated freshly isolated HSCs (induction of α-smooth muscle actin and fibrosis-associated genes) via a PDGFB-dependent mechanism. MOR8457 also reduced liver fibrosis in mice placed on DDC-supplemented diets. CONCLUSIONS: Platelets produce PDGFB to activate HSC and promote fibrosis in MDR2-null mice and mice on DDC-supplemented diets. Antiplatelet therapy or selective inhibition of PDGFB might reduce biliary fibrosis in patients with liver disease.

ALOX12 in human toxoplasmosis.

ALOX12 is a gene encoding arachidonate 12-lipoxygenase (12-LOX), a member of a nonheme lipoxygenase family of dioxygenases. ALOX12 catalyzes the addition of oxygen to arachidonic acid, producing 12-hydroperoxyeicosatetraenoic acid (12-HPETE), which can be reduced to the eicosanoid 12-HETE (12-hydroxyeicosatetraenoic acid). 12-HETE acts in diverse cellular processes, including catecholamine synthesis, vasoconstriction, neuronal function, and inflammation. Consistent with effects on these fundamental mechanisms, allelic variants of ALOX12 are associated with diseases including schizophrenia, atherosclerosis, and cancers, but the mechanisms have not been defined. Toxoplasma gondii is an apicomplexan parasite that causes morbidity and mortality and stimulates an innate and adaptive immune inflammatory reaction. Recently, it has been shown that a gene region known as Toxo1 is critical for susceptibility or resistance to T. gondii infection in rats. An orthologous gene region with ALOX12 centromeric is also present in humans. Here we report that the human ALOX12 gene has susceptibility alleles for human congenital toxoplasmosis (rs6502997 [P, <0.000309], rs312462 [P, <0.028499], rs6502998 [P, <0.029794], and rs434473 [P, <0.038516]). A human monocytic cell line was genetically engineered using lentivirus RNA interference to knock down ALOX12. In ALOX12 knockdown cells, ALOX12 RNA expression decreased and levels of the ALOX12 substrate, arachidonic acid, increased. ALOX12 knockdown attenuated the progression of T. gondii infection and resulted in greater parasite burdens but decreased consequent late cell death of the human monocytic cell line. These findings suggest that ALOX12 influences host responses to T. gondii infection in human cells. ALOX12 has been shown in other studies to be important in numerous diseases. Here we demonstrate the critical role ALOX12 plays in T. gondii infection in humans.