Rapid Rule-Based Reward Reversal and the Lateral Orbitofrontal Cortex

Humans and other primates can reverse their choice of stimuli in one trial when the rewards delivered by the stimuli change or reverse. Rapidly changing our behavior when the rewards change is important for many types of behavior, including emotional and social behavior. It is shown in a one-trial rule-based Go-NoGo deterministic visual discrimination reversal task to obtain points, that the human right lateral orbitofrontal cortex and adjoining inferior frontal gyrus is activated on reversal trials, when an expected reward is not obtained, and the non-reward allows the human to switch choices based on a rule. This reward reversal goes beyond model-free reinforcement learning. This functionality of the right lateral orbitofrontal cortex shown here in very rapid, one-trial, rule-based changes in human behavior when a reward is not received is related to the emotional and social changes that follow orbitofrontal cortex damage, and to depression in which this non-reward system is oversensitive and over-connected.

Andexanet versus prothrombin complex concentrates: Differences in reversal of factor Xa inhibitors in in vitro thrombin generation

BACKGROUND

Andexanet alfa (andexanet) is a modified human factor Xa (FXa) approved for anticoagulation reversal in patients with life-threatening bleeding treated with rivaroxaban or apixaban. Four-factor prothrombin complex concentrates (4F-PCCs) are approved for reversal of vitamin K antagonist-induced anticoagulation but not FXa inhibitors. The mechanism and effectiveness of 4F-PCCs for FXa inhibitor reversal are unclear.

OBJECTIVE

To investigate the mechanism and impact of 4F-PCCs on reversal of rivaroxaban and apixaban in vitro compared to andexanet.

METHODS

The effect of 4F-PCCs (or individual factors) on tissue factor-initiated thrombin generation (TF-TG) was evaluated in human plasma, with or without rivaroxaban or apixaban, and compared with andexanet under the same conditions.

RESULTS

In the TF-TG assay, 4F-PCC completely reversed warfarin anticoagulation. Andexanet normalized TF-TG over a wide range of apixaban and rivaroxaban concentrations tested (19-2000 ng/mL). However, 4F-PCC (or individual factors) was unable to normalize endogenous thrombin potential (ETP) or peak thrombin (Peak) in the presence of apixaban or rivaroxaban (75-500 ng/mL). TF-TG was only normalized by 4F-PCC at inhibitor concentrations <75 ng/mL (ETP) or <37.5 ng/mL (Peak). These data can be explained by the estimated thresholds of FXa activity required to support normal TF-TG based on the inhibitor:FXa ratios and levels of uninhibited FXa. The data are consistent with healthy volunteer studies where TF-TG is not normalized until inhibitor levels are substantially decreased.

CONCLUSIONS

Both the theoretical calculations and experimental data demonstrated that 4F-PCCs are only able to normalize TG over a low and narrow range of FXa inhibitor concentrations (<75 ng/mL).

Impact of Obesity on Warfarin Reversal With Fixed-Dose Factor VIII Inhibitor Bypassing Activity (aPCC)

BACKGROUND

Data are limited addressing anticoagulant reversal in obese patients using activated prothrombin complex concentrate (aPCC).

OBJECTIVE

Assess the impact of obesity on INR reversal with fixed aPCC dosing.

METHODS

Institutional review board-approved, retrospective cohort conducted in a large academic medical center. Patients 18 years or older who received fixed-dose aPCC for warfarin-associated hemorrhage were included. Patients who received aPCC for any other indications or who had no follow-up INR after aPCC administration were excluded. Patients with an INR of 5 or greater received 1000 units aPCC, whereas those with INR less than 5 received 500 units aPCC, per institutional protocol. Patients were stratified into obese and nonobese based on body mass index. Primary end point was INR reversal, defined as repeat INR of 1.4 or less within 4 hours following aPCC treatment, without a repeated dose. Secondary end points included percentage change in INR, proportion of patients requiring an additional dose of aPCC, bleeding complications, thrombotic complications, hospital length of stay, and in-hospital mortality.

RESULTS

259 patients were included, of whom 83 were obese (32%). A significantly higher proportion of nonobese patients achieved an INR of 1.4 or less within 4 hours of treatment (169 [96.02%] vs 69 [83.13%]; P = 0.0004). There were no differences in any secondary end points.

CONCLUSION AND RELEVANCE

When fixed-dose aPCC is used for warfarin reversal, obesity is associated with a significantly lower rate of INR reversal, without increased bleeding. This study adds to the limited amount of literature on aPCC dosing in obesity.

Sapitinib Reverses Anticancer Drug Resistance in Colon Cancer Cells Overexpressing the ABCB1 Transporter

The efficacy of anti-cancer drugs in patients can be attenuated by the development of multi-drug resistance (MDR) due to ATP-binding cassette (ABC) transporters overexpression. In this in vitro study, we determined the reversal efficacy of the epidermal growth factor receptor (EFGR) inhibitor, saptinib, in SW620 and SW720/Ad300 colon cancer cells and HEK293/ABCB1 cells which overexpress the ABCB1 transporter. Sapitinib significantly increased the efficacy of paclitaxel and doxorubicin in ABCB1 overexpressing cells without altering the expression or the subcellular location of the ABCB1 transporter. Sapitinib significantly increased the accumulation of [³H]-paclitaxel in SW620/AD300 cells probably by stimulating ATPase activity which could competitively inhibit the uptake of [³H]-paclitaxel. Furthermore, sapitinib inhibited the growth of resistant multicellular tumor spheroids (MCTS). The docking study indicated that sapitinib interacted with the efflux site of ABCB1 transporter by π-π interaction and two hydrogen bonds. In conclusion, our study suggests that sapitinib surmounts MDR mediated by ABCB1 transporter in cancer cells.

The Association of ICH Exclusion Criteria With Mortality and Disability Rates in ICH Patients Receiving 4F-PCC for Anticoagulation Reversal

BACKGROUND

Intracranial hemorrhage (ICH) exclusion criteria in the landmark four-factor prothrombin complex concentrate (4F-PCC) trial have not been incorporated into clinical practice and incremental predictive ability is unknown.

OBJECTIVES

Evaluate the association of meeting at least 1 ICH exclusion criterion with the composite end point in-hospital mortality and modified Rankin Scale [mRS] score 5 or 6. Determine the number and combination of criteria associated with poor outcomes.

METHODS

Retrospective review of adult ICH patients who received 4F-PCC for anticoagulant reversal. Patient demographics, ICH exclusion criteria, in-hospital mortality, disability, and disposition were collected. χ² Analysis and logistic regression were used to assess differences between patients with and without ICH exclusion criteria.

RESULTS

Data from 167 patients were analyzed: 103 (61.7%) met at least 1 ICH exclusion criterion. The composite end point occurred more in those with at least 1 ICH exclusion criterion (74.8% vs 39%; P < 0.0001). Presence of 2 or more ICH exclusion criteria was associated with higher odds of the composite end point, higher mRS score, and long-term care facility disposition (P < 0.0001). Glasgow Coma Scale score <7 and at least 1 other ICH exclusion criterion had negative effects on composite end point and mortality: 95% to 100% and 85% to 100%, respectively.

CONCLUSION AND RELEVANCE

Patients meeting at least 1 ICH exclusion criterion had greater death/disability compared with those who did not. More ICH exclusion criteria were associated with higher rates of death, disability, and worse disposition. These data may aid in developing optimal 4F-PCC use criteria.

Progressive hydrocephalus despite early complete reversal of hindbrain herniation after prenatal open myelomeningocele repair

OBJECTIVE

Open prenatal myelomeningocele (MMC) repair is typically associated with reversal of in utero hindbrain herniation (HBH) and has been posited to be associated with a reduction in both postoperative prenatal and immediate postnatal hydrocephalus (HCP) risks. However, the long-term postnatal risk of HCP following HBH reversal in these cases has not been well defined. The authors describe the results of a long-term HCP surveillance in a cohort of patients who underwent prenatal MMC repair at their institution.

METHODS

A retrospective review of all prenatal MMC repair operations performed at the Mayo Clinic between 2012 and 2017 was conducted. Pertinent data regarding the clinical courses of these patients before and after MMC repair were summarized. Outcomes of interest were occurrences of HBH and HCP and the need for intervention.

RESULTS

A total of 9 prenatal MMC repair cases were identified. There were 7 cases in which MRI clearly demonstrated prenatal HBH, and of these 86% (6/7) had evidence of HBH reversal after repair and prior to delivery. After a mean postnatal follow-up of 20 months, there were 3 cases of postnatal HCP requiring intervention. One case that failed to show complete HBH reversal after MMC repair required early ventriculoperitoneal shunting. The other 2 cases were of progressive, gradual-onset HCP despite complete prenatal HBH reversal, requiring endoscopic third ventriculostomy with choroid plexus cauterization at ages 5 and 7 months.

CONCLUSIONS

Although prenatal MMC repair can achieve HBH reversal in a majority of well-selected cases, the prevention of postnatal HCP requiring intervention appears not to be predicated on this outcome alone. In fact, it appears that in a subset of cases in which HBH reversal is achieved, patients can experience a progressive, gradual-onset HCP within the 1st year of life. These findings support continued rigorous postnatal surveillance of all prenatal MMC repair patients, irrespective of postoperative HBH outcome.

Robust Iterative Stimulation with Self-Antigens Overcomes CD8+ T Cell Tolerance to Self- and Tumor Antigens

The immune system adapts to constitutive antigens to preserve self-tolerance, which is a major barrier for anti-tumor immunity. Antigen-specific reversal of tolerance constitutes a major goal to spur therapeutic applications. Here, we show that robust, iterative, systemic stimulation targeting tissue-specific antigens in the context of acute infections reverses established CD8⁺ T cell tolerance to self, including in T cells that survive negative selection. This strategy results in large numbers of circulating and resident memory self-specific CD8⁺ T cells that are widely distributed and can be co-opted to control established malignancies bearing self-antigen without concomitant autoimmunity. Targeted expansion of both self- and tumor neoantigen-specific T cells acts synergistically to boost anti-tumor immunity and elicits protection against aggressive melanoma. Our findings demonstrate that T cell tolerance can be re-adapted to responsiveness through robust antigenic exposure, generating self-specific CD8⁺ T cells that can be used for cancer treatment.

Reversing Bleeding Associated With Antiplatelet Use: The Role of Tranexamic Acid

Dual antiplatelet therapy (DAPT) is the mainstay of therapy in patients that have been diagnosed with coronary artery disease. DAPT has known risk factors such as an increased risk of bleeding, and, currently, no specific medication is indicated to reverse bleeding associated with antiplatelet use. One medication that may help reduce blood loss is tranexamic acid (TXA). A retrospective review of the literature regarding TXA in the setting of antiplatelet associated bleeding through a systematic search strategy was conducted. This review of the literature followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines and included seven studies. Multiple studies demonstrated the impact on platelet function resulting from administering TXA through lower volumes of blood loss, lower transfusion requirements, and lower incidence of reoperations. TXA is not widely recommended to reverse antiplatelet medications; however, it is widely available, has a positive track record for use in various types of bleeding, and is relatively inexpensive and safe. Large-scale randomized trials are warranted to make a strong recommendation for TXA in reversing bleeding associated with antiplatelet therapy.

Reversal of ochronotic pigmentation in alkaptonuria following nitisinone therapy: Analysis of data from the United Kingdom National Alkaptonuria Centre

BACKGROUND

Increased homogentisic acid (HGA) causes ochronosis. Nitisinone decreases HGA. The aim was to study the effect of nitisinone on the ochronosis progression.

METHODS

Photographs of the eyes and ears were acquired from patients attending the National Alkaptonuria Centre (NAC) at V-1 (pre-baseline visit), V0 (baseline visit when 2 mg nitisinone was commenced), and yearly at V1, V2, and V3 visits. Photographs were inspected for evolution of ochronotic pigment and also scored categorically to derive eye, ear, and combined ochronosis scores. An ear cartilage biopsy was also carried out at V0 and one year after V3 (V4) and ochronotic pigment was assessed and quantitated. Visits were compared for changes in pigment. Fasting blood and 24-hour urine samples were collected for measurement of HGA.

RESULTS

There were 80 AKU patients at V0, and 52, 47, and 40 at V1, V2, and V3 in the group with variable numbers (VAR Group) respectively; 23 patients attended once before V0, in the V-1 visit. Photographs of patients show increase in eye pigment between V-1 and V0, followed by decrease post-nitisinone at V1, V2, and V3. Ear and combined ochronosis semiquantitative scoring showed an increase between V-1 and V0 (P < .01), followed by a decrease at V1, V2, and V3, in the VAR group (P < .01). Ochronotic pigment in ear biopsy between V0 and V4 showed a 19.1% decrease (P < .05).

CONCLUSIONS

Nitisinone decreases HGA and partially reverses ochronosis.

Premature graying of hair: Risk factors, co-morbid conditions, pharmacotherapy and reversal-A systematic review and meta-analysis

Premature graying of hair (PGH) being a very common entity for which pharmacotherapy and reversibility are not properly addressed. Therefore, this systematic review was conducted to address these issues. For this relevant study were selected from various databases including PubMed, EMBASE, OVID, Web of science, Scopus, and Google Scholar till January 20, 2019. Studies which reported risk factors, co-morbid conditions associated with PGH, its pharmacotherapy and reversal were included in the study. Although many risk factors are reported in literature, smoking, vitamin deficiency (B12, folic acid, and B7), mineral deficiency (low serum calcium and serum ferritin) are found to be associated with PGH. Other important risk factors are family history of PGH, obesity, high B.P, lack of exercise, drugs, genetic syndromes, dyslipidemia, thyroid disorders, hyperuricemia, and alteration in liver function. PGH is found to be an important marker of CAD, more so in case of smoker. Among different pharmacotherapeutic management options, low grade recommendation (2A) is given to calcium pantothenate, PABA, calcium pantothenate + PABA combination. Anu-tailam is the only herbal agent evaluated in clinical research settings. Finally, treating the accompanying pathologies led to the reversal of the disease in many cases.

Restoring Blood Pressure in Hypertensive Mice Fails to Fully Reverse Vascular Stiffness

Background

Hypertension is a well-established driver of vascular remodeling and stiffening. The goal of this study was to evaluate whether restoring normal blood pressure (BP) fully restores vascular stiffness toward that of normotensive controls.

Methods

C57Bl6/J male mice received angiotensin II (angII; 1 μg/kg/min) via infusion pump for 8 weeks (hypertension group: HH), angII for 4 weeks (hypertension group: H4), angII for 4 weeks followed by 4 weeks of recovery (reversal group: HN), or sham treatment (normotensive group: NN). BP, heart rate, and pulse wave velocity (PWV) were measured longitudinally. At the end of the study period, aortas were harvested for testing of vasoreactivity, passive mechanical properties, and vessel structure.

Results

The HH group exhibited a sustained increase in BP and PWV over the 8-week period (p < 0.01). In the HN group, BP and PWV increased during the 4-week angII infusion, and, though BP was restored during the 4-week recovery, PWV exhibited only partial restoration (p < 0.05). Heart rate was similar in all cohorts. Compared to NN controls, both HH and HN groups had significantly increased wall thickness (p < 0.05 HH vs. NN, p < 0.01 HN vs. NN), mucosal extracellular matrix accumulation (p < 0.0001 HH vs. NN, p < 0.05 HN vs. NN), and intralamellar distance (p < 0.001 HH vs. NN, p < 0.01 HN vs. NN). Both intact and decellularized vessels were noted to have significantly higher passive stiffness in the HH and H4 cohorts than in NN controls (p < 0.0001). However, in the HN cohort, intact vessels were only modestly stiffer than those of NN controls, and decellularized HN vessels were identical to those from the NN controls. Compared to NN controls, the HH and HN cohorts exhibited significantly diminished phenylephrine-induced contraction (p < 0.0001) and endothelium-dependent vasodilation (p < 0.05).

Conclusion

Hypertension causes a significant increase in in vivo aortic stiffness that is only partially reversible after BP normalization. Although hypertension does lead to matrix stiffening, restoration of BP restores matrix mechanics to levels similar to those of normotensive controls. Nevertheless, endothelial and vascular smooth muscle cell dysfunction persist after restoration of normotension. This dysfunction is, in part, responsible for augmented PWV after restoration of BP.

The feasibility and safety of early ileostomy reversal: a systematic review and meta-analysis

BACKGROUND

Recent evidence supports the safety of early reversal of a temporary stoma, within 14 days of construction. The aim of this systematic review and meta-analysis was to evaluate the post-operative morbidity and overall feasibility of early stoma reversal.

METHODS

Medline and Cochrane databases were searched for studies up to June 2019 that investigated the outcomes of early stoma reversal (EC, defined as closure ≤14 days from the index operation) versus late stoma reversal (LC, ≥8 weeks from the index operation). Meta-analysis was performed on the respective rates of post-operative morbidity, anastomotic leak, wound infection, bleeding, sepsis, small bowel obstruction and ileus.

RESULTS

Nine studies were included (667 patients analysed). Meta-analysis showed no significant difference in the post-operative morbidity rate, anastomotic leak rate, rates of small bowel obstruction, bleeding and ileus between EC and LC. However, the wound infection rate was significantly higher after EC than LC; relative difference 0.10 (95% confidence interval 0.00-0.19, P = 0.047). The stoma-related complication rate was significantly higher after LC than EC; relative difference -0.28 (95% confidence interval -0.45 to -0.11, P = 0.001).

CONCLUSION

The concept of early stoma reversal is appealing, and this meta-analysis confirms the safety of early stoma closure with an associated reduction in stoma-related complications despite higher wound infection rates. However, the results need to be interpreted with caution due to the heterogeneity of the studies included, especially in respect of the definition of complications that were used. Further well-designed prospective studies are required prior to confident adoption of early stoma closure into clinical practice.

Will the plant-based movement redefine physicians' understanding of chronic disease?

The world is experiencing a cataclysmically increasing burden from chronic illnesses. Chronic diseases are on the advance worldwide and treatment strategies to counter this development are dominated by symptom control and polypharmacy. Thus, chronic conditions are often considered irreversible, implying a slow progression of disease that can only be hampered but not stopped. The current plant-based movement is attempting to alter this way of thinking. Applying a nutrition-first approach, the ultimate goal is either disease remission or reversal. Hereby, ethical questions arise as to whether physicians' current understanding of chronic illness is outdated and morally reprehensible. In this case, physicians may need to recommend plant-based diets to every patient suffering from chronic conditions, while determining what other socioecological factors and environmental aspects play a role in the chronic disease process. This article provides insights to aspects of diet and chronic illness and discusses how the plant-based movement could redefine current understanding of chronic disease. The ethical justifications for recommending of a plant-based diet are analyzed. The article concludes that not advocating for plant-based nutrition is unethical and harms the planet and patients alike.

Type 2 Diabetes Remission and Lifestyle Medicine: A Position Statement From the American College of Lifestyle Medicine

Objectives. The present review represents the position of the American College of Lifestyle Medicine on type 2 diabetes (T2D) and remission treatment. Background. Research now reveals that sufficiently intensive lifestyle interventions can produce remission of T2D with similar success to bariatric surgery, but with substantially fewer untoward side effects. Methods. A literature review was conducted to examine lifestyle modifications targeting T2D remission, with most studies using a combination of blood glucose markers and treatment history. Results. There were notable differences in the dosing intensity of lifestyle interventions between therapeutic interventions and subtherapeutic interventions. Studies with therapeutic dosing typically used very low energy diets (600-1100 kcal/day) with a weighted mean remission rate of 49.4%, while studies with subtherapeutic dosing typically used more moderate caloric restrictions (reducing energy intake by 500-600 kcal/day) and the weighted mean remission rate was 6.9%. Conclusions. Remission should be the clinical goal in T2D treatment, using properly dosed intensive lifestyle interventions as a primary component of medical care for T2D patients.

Emergent Warfarin Reversal With Fixed-Dose 4-Factor Prothrombin Complex Concentrate

BACKGROUND

Four-factor prothrombin complex concentrate (4FPCC) is used for emergent warfarin reversal, but dosing remains controversial. Following approval, further studies have evaluated a variety of fixed-dose regimens. The studies utilized lower doses as compared with package insert dosing and provided data in regard to efficacy, safety, and cost savings. Further data are needed, however, to determine which fixed-dose regimen provides optimal efficacy and safety for emergent warfarin reversal.

OBJECTIVES

The purpose of this study is to evaluate the efficacy, safety, and cost-savings of a fixed-dose 4FPCC protocol.

METHODS

This multicentered, retrospective chart review of adult patients requiring 4FPCC for emergent warfarin reversal utilized a fixed-dose regimen of 1500 units. The 2 primary outcomes were the proportion of patients who achieved a post-4FPCC international normalized ratio (INR) of ≤1.5 and ≤2. Secondary outcomes included thrombotic events within 7 days of 4FPCC administration and survival to discharge. A cost analysis was also performed to identify potential cost savings.

RESULTS

Of the 64 patients included, 44 (68.8%) achieved a post-4FPCC INR ≤1.5, and 61 (95.3%) achieved a post-4FPCC INR ≤2.0. No thrombotic events were reported; 55 (85.9%) patients survived to hospital discharge. More than $1000 was saved per patient via utilization of the fixed-dose protocol.

CONCLUSION AND RELEVANCE

A fixed-dose of 1500 units of 4FPCC successfully achieved a target INR of ≤1.5 in the majority of patients and resulted in no thrombotic events. This study adds to the data evaluating alternative 4FPCC dosing regimens in comparison to package insert recommended dosing.

Comparison of rates of opioid withdrawal symptoms and reversal of opioid toxicity in patients treated with two naloxone dosing regimens: a retrospective cohort study

INTRODUCTION

When managing opioid overdose (OD) patients, the optimal naloxone regimen should rapidly reverse respiratory depression while avoiding opioid withdrawal. Published naloxone administration guidelines have not been empirically validated and most were developed before fentanyl OD was common. In this study, rates of opioid withdrawal symptoms (OW) and reversal of opioid toxicity in patients treated with two naloxone dosing regimens were evaluated.

METHODS

In this retrospective matched cohort study, health records of patients who experienced an opioid OD treated in two urban emergency departments (ED) during an ongoing fentanyl OD epidemic were reviewed. Definitions for OW and opioid reversal were developed a priori. Low dose naloxone (LDN; ≤0.15 mg) and high dose naloxone (HDN; >0.15 mg) patients were matched in a 1:4 ratio based upon initial respiratory rate (RR). The proportion of patients who developed OW and who met reversal criteria were compared between those treated initially with LDN or HDN. Odds ratios (OR) for OW and opioid reversal were obtained via logistic regression stratified by matched sets and adjusted for age, sex, pre-naloxone GCS, and presence of non-opioid drugs or alcohol.

RESULTS

Eighty LDN patients were matched with 299 HDN patients. After adjustment, HDN patients were more likely than LDN patients to have OW after initial dose (OR = 8.43; 95%CI: 1.96, 36.3; p = 0.004) and after any dose (OR = 2.56; 95%CI: 1.17, 5.60; p = 0.019). HDN patients were more likely to meet reversal criteria after initial dose (OR = 2.73; 95%CI: 1.19, 6.26; p = 0.018) and after any dose (OR = 6.07; 95%CI: 1.81, 20.3; p = 0.003).

CONCLUSIONS

HDN patients were more likely to have OW but also more likely to meet reversal criteria versus LDN patients.

Coagulation Factor Xa (Recombinant), Inactivated-Zhzo (Andexanet Alfa) Hemostatic Outcomes and Thrombotic Event Incidence at an Academic Medical Center

Andexanet alfa is approved for the reversal of factor Xa inhibitors in patients with major bleeding events. We aimed to review the incidence of effective hemostasis with andexanet alfa in a real-world environment. This retrospective cohort included patients hospitalized for a major bleed that resulted in andexanet alfa administration. The primary outcome was effective hemostasis at 12 hours after andexanet alfa treatment. Thromboembolic events and mortality within 30 days were also assessed. Over a 14-month period, 13 patients received andexanet alfa with a mean age of 69 ± 10 years, 54% male, 69% exposed to apixaban (31% rivaroxaban), and had intracranial (46%) and nonintracranial (54%) bleeding sites. Effective hemostasis was observed in 10 (77%) patients. Four (31%) patients experienced 5 thromboembolic events with a median time to event of 6.5 days (range: 0.5-29). Four thrombotic events occurred during the period in which anticoagulation (prophylaxis or therapeutic) was not restarted. Mortality rate was 15%. Andexanet alfa was effective in obtaining hemostasis in a majority of patients. However, the incidence of thromboembolic events was high and may be attributed to a delay in restarting anticoagulation.

Pro- and Anti-fibrogenic Functions of Gram-Negative Bacterial Lipopolysaccharide in the Liver

Extensive research performed over several decades has identified cells participating in the initiation and progression of fibrosis, and the numerous underlying inter- and intra-cellular signaling pathways. However, liver fibrosis continues to be a major clinical challenge as the precise targets of treatment are still elusive. Activation of physiologically quiescent perisinusoidal hepatic stellate cells (HSCs) to a myofibroblastic proliferating, contractile and fibrogenic phenotype is a critical event in the pathogenesis of chronic liver disease. Thus, elucidation of the mechanisms of the reversal to quiescence or inhibition of activated HSCs, and/or their elimination via apoptosis has been the focus of intense investigation. Lipopolysaccharide (LPS), a gut-resident Gram-negative bacterial endotoxin, is a powerful pro-inflammatory molecule implicated in hepatic injury, inflammation and fibrosis. In both acute and chronic liver injury, portal venous levels of LPS are elevated due to increased intestinal permeability. LPS, via CD14 and Toll-like receptor 4 (TLR4) and its adapter molecules, stimulates macrophages, neutrophils and several other cell types to produce inflammatory mediators as well as factors that can activate HSCs and stimulate their fibrogenic activity. LPS also stimulates synthesis of pro- and anti-inflammatory cytokines/chemokines, growth mediators and molecules of immune regulation by HSCs. However, LPS was found to arrest proliferation of activated HSCs and to convert them into non-fibrogenic phenotype. Interestingly, LPS can elicit responses in HSCs independent of CD14 and TLR4. Identifying and/or developing non-inflammatory but anti-fibrogenic mimetics of LPS could be relevant for treating liver fibrosis.

Analysis of anticoagulation reversal survey (ARES)

OBJECTIVES

Despite the availability of FDA-labeled anticoagulant reversal agents, there is considerable variability in clinical practice as to the regimen and agent used for reversal. The objective of this study was to characterize the current practices of pharmacists surrounding the reversal of anticoagulant-associated life-threatening hemorrhage. Methods: A cross-sectional analysis of critical care and emergency medicine pharmacists. Current practice was compared for the type of hospital, country region, and type of ordering physician. In addition, pharmacists were asked to rank their involvement with activities involved with the reversal of anticoagulants. Respondents ranked their involvement with these activities as either never involved, rarely involved, occasionally involved, frequently involved, or always involved. Results:281 respondents were included. The majority used 4-factor PCC for warfarin reversal (92.9%) and factor Xa inhibitor reversal (79.7%). However, only 58.7% used the labeled dose of 4-PCC for warfarin reversal. Of the 30.6% that utilized a fixed-dose regimen, the most common regimen was 1500 units once. A higher proportion of respondents practicing in a teaching hospital reported that they used activated prothrombin complex concentrates for reversal of factor Xa inhibitor (22 [12.2%] vs. 5 [5%]; p < 0.05) or coagulation factor Xa (recombinant)-inactivated-zhzo (31 [17.2%] vs. 5 [5%]; p < 0.05). In addition, the majority of respondents utilized idarucizumab for dabigatran reversal. The only involvement activity in which <50% of respondents said they were frequently involved or always involved was 'administration of reversal agent.' Conclusions: There is considerable variability in which agents were utilized for anticoagulant-associated bleeding reversal.

Reversal of HER2 Negativity: An Unexpected Role for Lovastatin in Triple-Negative Breast Cancer Stem Cells

Effective treatment modality for triple-negative breast cancer (TNBC) is currently lacking due to the absence of defined receptor targets. Recently, we have demonstrated that lovastatin, a 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor and a lipid-lowering drug, can selectively inhibit TNBC by targeting cancer stem cells in vivo and in vitro. Interestingly, we found that lovastatin induced the reappearance of human epidermal growth factor receptor 2 (HER2), one of the triple receptors that are missing in TNBC. This prompted us to explore the possibility of regaining sensitivity of TNBC cancer stem cells to receptor tyrosine kinase-targeting drugs. We found that while the combination of lovastatin with a HER2 inhibitor was not sufficient to show synergism, addition of an epidermal growth factor receptor (EGFR/HER1) inhibitor to this combination resulted in significant synergistic inhibitory effect on cell viability. Our findings provide a potential novel strategy of designing a cocktail composed of a lipid-lowering drug and two receptor tyrosine kinase inhibitors for the treatment of TNBC.

Comparative In Vitro Study of Various α2-Adrenoreceptor Agonist Drugs for Ticagrelor Reversal

Ticagrelor, an antiplatelet adenosine diphosphate (ADP)-P2Y₁₂ receptor antagonist, increases the risk of bleeding. Its management is challenging because platelet transfusion is ineffective and no specific antidote is currently available. Epinephrine, a vasopressor catecholamine prescribed during shock, restores platelet functions inhibited by ticagrelor through stimulation of α_2A-adrenoreceptors. It subsequently inhibits cyclic adenosine monophosphate (cAMP) pathway and PI3K signaling. However, since epinephrine may expose a patient to deleterious hemodynamic effects, we hypothesized that other α₂-adrenoreceptor agonist drugs used in clinical practice with fewer side effects could reverse the antiplatelet effects of ticagrelor. We compared in vitro the efficacy of clonidine, dexmedetomidine, brimonidine, and norepinephrine with epinephrine to restore ADP- and PAR-1-AP-induced washed platelet aggregation inhibited by ticagrelor, as well as resulting platelet cAMP levels. In ticagrelor-free samples, none of the α₂-adrenoreceptor agonists induced aggregation by itself but all of them potentiated ADP-induced aggregation. Compared with epinephrine, norepinephrine, and brimonidine partially restored ADP- and fully restored PAR-1-AP-induced aggregation inhibited by ticagrelor while clonidine and dexmedetomidine were ineffective. Indeed, this lack of effect resulted from a lower decrease in cAMP concentration elicited by these partial α₂-adrenoreceptor agonists, clonidine, and dexmedetomidine, compared with full α₂-agonists. Our results support the development of specific full and systemic α₂-adrenoreceptor agonists for ticagrelor reversal.

Impact of Sugammadex Versus Neostigmine/Glycopyrrolate on Perioperative Efficiency

Purpose

Neuromuscular blockade in the operating room necessitates the utilization of reversal agents to accelerate postoperative recovery and sustain operating room patient throughput. Cholinesterase inhibitors represent the historical standard of care for neuromuscular blockade reversal within anesthesia practice. Sugammadex, a synthetic gamma-cyclodextrin, was introduced to the market with evidence of more rapid and predictable reversal of neuromuscular blockade compared to alternative agents. Higher medication acquisition costs have limited more extensive use of sugammadex compared to that of neostigmine/glycopyrrolate. The purpose of this study was to examine the impact of sugammadex versus neostigmine/glycopyrrolate on perioperative efficiency to validate medication acquisition cost value.

Methods

A retrospective investigation was performed of patients with a surgical procedure at Houston Methodist Hospital from July 31, 2017 through August 1, 2018. The primary endpoint was time from reversal medication administration to operating room exit. Patient-specific doses were assessed to calculate average medication acquisition costs. The economic benefits of sugammadex were measured through review of average operating room and postanesthesia care unit costs per minute.

Results

There were a total of 640 surgical cases at Houston Methodist Hospital eligible for inclusion into the research study. The time from medication administration to operating room exit was significantly faster for sugammadex compared to neostigmine/glycopyrrolate (P<0.001) upon univariate analysis. However, when measured with linear regression, the difference in operating room exit time between sugammadex and neostigmine/glycopyrrolate was no longer statistically significant (P=0.122). Medication acquisition cost review highlighted a difference of $178.20, favoring use of neostigmine/glycopyrrolate.

Conclusion

The utilization of sugammadex does not correlate to consequential time saved in the operating room or extrapolation to workflow capacity for increased surgical case volume. Consideration of the medication acquisition cost promotes more restrictive use of sugammadex to indications with clinical relevance.

Utilization of 4-Factor Prothrombin Complex Concentrate for Reversal of Oral Factor Xa Inhibitor-Associated Acute Major Bleeding: A Case Series

OBJECTIVE

In cases of oral factor Xa (FXa) inhibitor-associated acute major bleeding, several reversal strategies are available. Current guidelines recommend a dose of 50 U/kg if using 4-factor prothrombin complex concentrate (4F-PCC). A paucity of data exists with the use of 4F-PCC for FXa inhibitor reversal for acute major bleeding, specifically the most efficacious dosing regimens and safety data. The purpose of this case series is to describe the utilization of 4F-PCC for reversal of oral FXa inhibitor-associated acute major bleeding.

METHODS

This retrospective case series included all admitted patients 18 years and older who received 4F-PCC for oral FXa inhibitor-associated major bleeding. Major bleeding was defined using the International Society of Thrombosis and Hemostasis definition for major bleeding in nonsurgical patients. The primary outcome was achievement of hemostasis.

RESULTS

A total of 31 patients met inclusion criteria, with 17 receiving rivaroxaban and 14 receiving apixaban. Intracranial hemorrhage was the most common type of bleeding occurring in 15 (55%) patients. The median dose of 4F-PCC was 37 U/kg. Of the patients evaluated in the primary end point analysis, 68% achieved effective hemostasis. Four (12.9%) patients experienced a documented thrombotic event within 7 days of receiving 4F-PCC.

CONCLUSION

The use of 4F-PCC for FXa inhibitor-associated acute major bleeding was effective for the majority of patients. The rate of thrombotic events appears higher compared to previously published studies, although major confounders exist and larger studies are needed to fully evaluate the safety of 4F-PCC for this indication.

Separating Probability and Reversal Learning in a Novel Probabilistic Reversal Learning Task for Mice

The exploration/exploitation tradeoff – pursuing a known reward vs. sampling from lesser known options in the hope of finding a better payoff – is a fundamental aspect of learning and decision making. In humans, this has been studied using multi-armed bandit tasks. The same processes have also been studied using simplified probabilistic reversal learning (PRL) tasks with binary choices. Our investigations suggest that protocols previously used to explore PRL in mice may prove beyond their cognitive capacities, with animals performing at a no-better-than-chance level. We sought a novel probabilistic learning task to improve behavioral responding in mice, whilst allowing the investigation of the exploration/exploitation tradeoff in decision making. To achieve this, we developed a two-lever operant chamber task with levers corresponding to different probabilities (high/low) of receiving a saccharin reward, reversing the reward contingencies associated with levers once animals reached a threshold of 80% responding at the high rewarding lever. We found that, unlike in existing PRL tasks, mice are able to learn and behave near optimally with 80% high/20% low reward probabilities. Altering the reward contingencies towards equality showed that some mice displayed preference for the high rewarding lever with probabilities as close as 60% high/40% low. Additionally, we show that animal choice behavior can be effectively modelled using reinforcement learning (RL) models incorporating learning rates for positive and negative prediction error, a perseveration parameter, and a noise parameter. This new decision task, coupled with RL analyses, advances access to investigate the neuroscience of the exploration/exploitation tradeoff in decision making.

Reversal of Factor Xa Inhibitors by Andexanet Alfa May Increase Thrombogenesis Compared to Pretreatment Values

Recombinant coagulation factor Xa (FXa), inactivated Zh-zo, also known as andexanet alfa (AA), is a modified version of human FXa that has been developed to neutralize FXa inhibitors. We studied the reversal effect of AA for these inhibitors in various anticoagulant and thrombin generation (TG) assays. Individual aliquots of normal human plasma containing 1 µg/mL of apixaban, betrixaban, edoxaban, and rivaroxaban, were supplemented with saline or AA at a concentration of 100 µg/mL. Clotting profiles include prothrombinase-induced clotting time, activated partial thromboplastin time, and prothrombin time. Factor Xa activity was measured using an amidolytic method. Thrombin generation was measured using a calibrated automated thrombogram. Differential neutralization of all 4 anticoagulants was noted in the activated clotting time and other clotting tests. The FXa activity reversal profile varied with an observed decrease in apixaban (22%), betrixaban (56%), edoxaban (28%), and rivaroxaban (49%). Andexanet alfa also led to an increased TG in comparison to saline. The peak thrombin was higher (40%), area under the curve (AUC) increased (15%), whereas the lag time (LT) decreased (17%). Andexanet alfa added at 100 µg/mL to various FXa supplemented systems resulted in reversal of the inhibitory effects, restoring the TG profile; AUC, LT, and peak thrombin levels were comparable to those of unsupplemented samples. Andexanet alfa is capable of reversing anti-Xa activity of different oral FXa inhibitors but overshoots thrombogenesis in both the saline and FXa inhibitor supplemented systems. The degree of neutralization of Xa inhibitor is specific to each agent.