Investigating Unconscious Race Bias and Bias Awareness Among Vascular Surgeons.

Background: Implicit bias can influence behavior and decision-making. In clinical settings, implicit bias may influence treatment decisions and contribute to health disparities. Given documented Black-White disparities in vascular care, the purpose of this study was to examine the prevalence and degree of unconscious bias and awareness of bias among vascular surgeons treating peripheral artery disease (PAD). Methods: The sampling frame included all vascular surgeons who participate in the Vascular Quality Initiative (VQI). Participants completed a survey which included demographic questions, the race implicit association test (IAT) to measure magnitude of unconscious bias, and six bias awareness questions to measure conscious bias. The magnitude of unconscious bias was no preference; or slight, moderate, or strong in the direction of pro-White or pro-Black. Data from participants were weighted to account for nonresponse bias and known differences in the characteristics of surgeons who chose to participate compared to the full registry. We stratified unconscious and conscious findings by physician race/ethnicity, physician sex, and years of experience. Finally, we examined the relationship between unconscious and conscious bias. Results: There were 2,512 surgeons in the VQI registry, 304 of whom completed the survey, including getting IAT results. Most participants (71.6%) showed a pro-White bias with 73.0% of this group in the moderate and strong categories. While 77.5% of respondents showed conscious awareness of bias, of those whose conscious results showed lack of awareness, 67.8% had moderate or strong bias, compared to 55.7% for those with awareness. Bias magnitude varied based on physician race/ethnicity and years of experience. Women were more likely than men to report awareness of biases and potential impact of bias on decision-making. Conclusions: Most people have some level of unconscious bias, developed from early life reinforcements, social stereotypes, and learned experiences. Regarding health disparities, however, these are important findings in a profession that takes care of patients with PAD due to heavy burden of comorbid conditions and high proportion of individuals from structurally vulnerable groups. Given the lack of association between unconscious and conscious awareness of biases, awareness may be an important first step in mitigation to minimize racial disparities in healthcare.

Examining the acceptability and feasibility of the Compassionate Mindful Resilience (CMR) programme in adults living with chronic kidney disease: the COSMIC study findings.

BACKGROUND: Individuals with chronic kidney disease experience difficult physical and psychological symptoms, that impact quality of life, and are at increased risk of anxiety and depression. Access to specialist psychological support is limited. This study aimed to support a new service development project, in collaboration with Kidney Care UK, to implement the Compassionate Mindful Resilience (CMR) programme, developed by MindfulnessUK, which provides accessible mindfulness techniques and practices to enhance compassion and resilience, and explore its feasibility for people living with stage 4 or 5 kidney disease and transplant. METHODS: A multi-method feasibility design was utilised. Participants over 18 years, from the UK, with stage 4 or 5 kidney disease or post-transplant, and who were not currently undergoing psychotherapy, were recruited to the four-week CMR programme. Data was collected at baseline, post-intervention and three-months post to measure anxiety, depression, self-compassion, mental wellbeing, resilience, and mindfulness. The acceptability of the intervention for a kidney disease population was explored through qualitative interviews with participants, and the Mindfulness Teacher. RESULTS: In total, 75 participants were recruited to the study, with 65 completing the CMR programme. The majority were female (66.2%) and post-transplant (63.1%). Analysis of completed outcome measures at baseline and post-intervention timepoints (n = 61), and three-months post intervention (n = 45) revealed significant improvements in participant's levels of anxiety (p < .001) and depression (p < .001), self-compassion (p = .005), mental wellbeing (p < .001), resilience (p.001), and mindfulness (p < .001). Thematic analysis of interviews with participants (n = 19) and Mindfulness Teacher (n = 1) generated three themes (and nine-subthemes); experiences of the CMR programme that facilitated subjective benefit, participants lived and shared experiences, and practicalities of programme participation. All participants interviewed reported that they found programme participation to be beneficial. CONCLUSION: The findings suggest that the CMR programme has the potential to improve psychological outcomes among people with chronic kidney disease. Future randomized controlled trials are required to further test its effectiveness.

Experiences of People with Kidney Disease Following the Implementation of the Compassionate Mindful Resilience Programme: Qualitative Findings from the COSMIC Study.

BACKGROUND: Kidney disease is a progressive, debilitating condition. Patients experience challenging physical and psychological symptoms and are at increased risk of anxiety, depression, and poor mental wellbeing. Access to specialist psychological or social support is limited, with inadequate provision of psychosocial support available across UK renal units. The COSMIC study (examining the acceptability and feasibility of the Compassionate Mindful Resilience programme for adult patients with chronic kidney disease) aimed to support a new service development project, in partnership with Kidney Care UK, by implementing the Compassionate Mindful Resilience (CMR) programme, developed by MindfulnessUK, and explore its feasibility for patients with stage 4 or 5 kidney disease and kidney transplant recipients. This paper reports on the qualitative exploratory work which examined the experiences of study participants, their adherence to practice, and the acceptability of the intervention. METHOD: Participants (n = 19) took part in semi-structured interviews, which were transcribed, coded, and thematically analysed. RESULTS: Three themes (and nine subthemes) were reported: experiences of the CMR programme that facilitated subjective benefit, participants' lived and shared experiences, and the practicalities of CMR programme participation. All participants reported that they found taking part in the CMR programme to be a beneficial experience. CONCLUSION: The CMR programme was found to be an acceptable intervention for people living with kidney disease and provided tools and techniques that support the mental health and wellbeing of this patient group. Further qualitative exploration into participant experience should be integrated within future trials of this intervention.

Consensus on a netball video analysis framework of descriptors and definitions by the netball video analysis consensus group.

Using an expert consensus-based approach, a netball video analysis consensus (NVAC) group of researchers and practitioners was formed to develop a video analysis framework of descriptors and definitions of physical, technical and contextual aspects for netball research. The framework aims to improve the consistency of language used within netball investigations. It also aims to guide injury mechanism reporting and identification of injury risk factors. The development of the framework involved a systematic review of the literature and a Delphi process. In conjunction with commercially used descriptors and definitions, 19 studies were used to create the initial framework of key descriptors and definitions in netball. In a two round Delphi method consensus, each expert rated their level of agreement with each of the descriptors and associated definition on a 5-point Likert scale (1-strongly disagree; 2-somewhat disagree; 3-neither agree nor disagree; 4-somewhat agree; 5-strongly agree). The median (IQR) rating of agreement was 5.0 (0.0), 5.0 (0.0) and 5.0 (0.0) for physical, technical and contextual aspects, respectively. The NVAC group recommends usage of the framework when conducting video analysis research in netball. The use of descriptors and definitions will be determined by the nature of the work and can be combined to incorporate further movements and actions used in netball. The framework can be linked with additional data, such as injury surveillance and microtechnology data.

Examining the Acceptability and Feasibility of the Compassionate Mindful Resilience (CMR) Programme in Adult Patients with Chronic Kidney Disease: The COSMIC Study Protocol.

Kidney disease is often progressive, and patients experience diminished health-related quality of life. In addition, the impact of the coronavirus (COVID-19) pandemic, and its associated restrictions, has brought many additional burdens. It is therefore essential that effective and affordable systems are explored to improve the psychological health of this group that can be delivered safely during the COVID-19 pandemic. The aim of this study is to support a new service development project in partnership with the UK's leading patient support charity Kidney Care UK by implementing the four-session Compassionate Mindful Resilience (CMR) programme, developed by MindfulnessUK, and explore its effectiveness for patients with stage 4 or 5 chronic kidney disease or have received a kidney transplant. The study will utilise a quasi-experimental, pretest/posttest design to measure the effect of the CMR programme on anxiety, depression, self-compassion, the ability to be mindful, wellbeing, and resilience, using pre- and posttests, alongside a qualitative exploration to explore factors influencing the feasibility, acceptability, and suitability of the intervention, with patients (and the Mindfulness Teacher) and their commitment to practice. Outcomes from this study will include an evidence-based mindfulness and compassion programme for use with people with kidney disease, which is likely to have applicability across other chronic diseases.

Mindfulness as a well-being initiative for future nurses: a survey with undergraduate nursing students.

BACKGROUND: Mindfulness can potentially positively impact well-being and resilience in undergraduate nursing students. The psychological well-being of such students undertaking clinical training is paramount to ensure optimal learning, and to equip them with skills to manage their wellbeing in future clinical practice. The aim of our study was to explore the views of undergraduate nursing students in relation to understanding and engaging with mindfulness, and how mindfulness could best be delivered within their university programme. METHODS: An online survey was administered via a cloud-based student response system to a convenience sample of first year undergraduate nursing students completing a Bachelor of Science (BSc) Honours (Hons) degree in nursing at a University in the United Kingdom. Data were analysed using descriptive statistics and thematic analysis. RESULTS: The survey achieved a response rate of 78% (n = 208). Seventy-nine percent of participants had heard of mindfulness and were interested in taking part in a mindfulness programme. Respondents reported that the ideal delivery of the programme would consist of weekly 45-min, in person group sessions, over a 6-week period. Respondents also indicated that a mobile application could potentially facilitate participation in the programme. Thematic analysis of open-ended comments, and free text, within the survey indicated 4 overarching themes: 1) Perceptions of what mindfulness is; 2) Previous mindfulness practice experiences; 3) Impact of mindfulness in nursing; 4) The need for a future well-being initiative for undergraduate nursing students. CONCLUSIONS: Undergraduate nursing students perceived that a mindfulness programme has the potential to enhance well-being and future clinical practice. This student cohort are familiar with mindfulness and want more integrated within their undergraduate curriculum. Further research is required to examine the effectiveness of a tailored mindfulness intervention for this population that incorporates the use of both face-to-face and mobile delivery.

Changes in mood and health-related quality of life in Look AHEAD 6 years after termination of the lifestyle intervention.

OBJECTIVE: The Action for Health in Diabetes (Look AHEAD) study previously reported that intensive lifestyle intervention (ILI) reduced incident depressive symptoms and improved health-related quality of life (HRQOL) over nearly 10 years of intervention compared with a control group (the diabetes support and education group [DSE]) in participants with type 2 diabetes and overweight or obesity. The present study compared incident depressive symptoms and changes in HRQOL in these groups for an additional 6 years following termination of the ILI in September 2012. METHODS: A total of 1,945 ILI participants and 1,900 DSE participants completed at least one of four planned postintervention assessments at which weight, mood (via the Patient Health Questionnaire-9), antidepressant medication use, and HRQOL (via the Medical Outcomes Scale, Short Form-36) were measured. RESULTS: ILI participants and DSE participants lost 3.1 (0.3) and 3.8 (0.3) kg [represented as mean (SE); p = 0.10], respectively, during the 6-year postintervention follow-up. No significant differences were observed between groups during this time in incident mild or greater symptoms of depression, antidepressant medication use, or in changes on the physical component summary or mental component summary scores of the Short Form-36. In both groups, mental component summary scores were higher than physical component summary scores. CONCLUSIONS: Prior participation in the ILI, compared with the DSE group, did not appear to improve subsequent mood or HRQOL during 6 years of postintervention follow-up.

Islet Autoimmunity in Adults With Impaired Glucose Tolerance and Recently Diagnosed, Treatment Naïve Type 2 Diabetes in the Restoring Insulin SEcretion (RISE) Study.

The presence of islet autoantibodies and islet reactive T cells (T+) in adults with established type 2 diabetes (T2D) have been shown to identify those patients with more severe ß-cell dysfunction. However, at what stage in the progression toward clinical T2D does islet autoimmunity emerge as an important component influencing ß-cell dysfunction? In this ancillary study to the Restoring Insulin SEcretion (RISE) Study, we investigated the prevalence of and association with ß-cell dysfunction of T+ and autoantibodies to the 65 kDa glutamic acid decarboxylase antigen (GADA) in obese pre-diabetes adults with impaired glucose tolerance (IGT) and recently diagnosed treatment naïve (Ndx) T2D. We further investigated the effect of 12 months of RISE interventions (metformin or liraglutide plus metformin, or with 3 months of insulin glargine followed by 9 months of metformin or placebo) on islet autoimmune reactivity. We observed GADA(+) in 1.6% of NdxT2D and 4.6% of IGT at baseline, and in 1.6% of NdxT2D and 5.3% of IGT at 12 months, but no significant associations between GADA(+) and ß-cell function. T(+) was observed in 50% of NdxT2D and 60.4% of IGT at baseline, and in 68.4% of NdxT2D and 83.9% of IGT at 12 months. T(+) NdxT2D were observed to have significantly higher fasting glucose (p = 0.004), and 2 h glucose (p = 0.0032), but significantly lower steady state C-peptide (sscpep, p = 0.007) compared to T(-) NdxT2D. T(+) IGT participants demonstrated lower but not significant (p = 0.025) acute (first phase) C-peptide response to glucose (ACPRg) compared to T(-) IGT. With metformin treatment, T(+) participants were observed to have a significantly lower Hemoglobin A1c (HbA1c, p = 0.002) and fasting C-peptide (p = 0.002) compared to T(-), whereas T(+) treated with liraglutide + metformin had significantly lower sscpep (p = 0.010) compared to T(-) participants. In the placebo group, T(+) participants demonstrated significantly lower ACPRg (p = 0.001) compared to T(-) participants. In summary, T(+) were found in a large percentage of obese pre-diabetes adults with IGT and in recently diagnosed T2D. Moreover, T(+) were significantly correlated with treatment effects and ß-cell dysfunction. Our results demonstrate that T(+) are an important component in T2D.

Precision and accuracy of hyperglycemic clamps in a multicenter study.

Application of glucose clamp methodologies in multicenter studies brings challenges for standardization. The Restoring Insulin Secretion (RISE) Consortium implemented a hyperglycemic clamp protocol across seven centers using a combination of technical and management approaches to achieve standardization. Two-stage hyperglycemic clamps with glucose targets of 200 mg/dL and >450 mg/dL were performed utilizing a centralized spreadsheet-based algorithm that guided dextrose infusion rates using bedside plasma glucose measurements. Clamp operators received initial and repeated training with ongoing feedback based on surveillance of clamp performance. The precision and accuracy of the achieved stage-specific glucose targets were evaluated, including differences by study center. We also evaluated robustness of the method to baseline physiologic differences and on-study treatment effects. The RISE approach produced high overall precision (3%-9% variance in achieved plasma glucose from target at various times across the procedure) and accuracy (SD < 10% overall). Statistically significant but numerically small differences in achieved target glucose concentrations were observed across study centers, within the magnitude of the observed technical variability. Variation of the achieved target glucose over time in placebo-treated individuals was low (<3% variation), and the method was robust to differences in baseline physiology (youth vs. adult, IGT vs. diabetes status) and differences in physiology induced by study treatments. The RISE approach to standardization of the hyperglycemic clamp methodology across multiple study centers produced technically excellent standardization of achieved glucose concentrations. This approach provides a reliable method for implementing glucose clamp methodology across multiple study centers.NEW & NOTEWORTHY The Restoring Insulin Secretion (RISE) study centers undertook hyperglycemic clamps using a simplified methodology and a decision guidance algorithm implemented in an easy-to-use spreadsheet. This approach, combined with active management including ongoing central data surveillance and routine feedback to study centers, produced technically excellent standardization of achieved glucose concentrations on repeat studies within and across study centers.

Within-Trial Cost-Effectiveness of a Structured Lifestyle Intervention in Adults With Overweight/Obesity and Type 2 Diabetes: Results From the Action for Health in Diabetes (Look AHEAD) Study.

OBJECTIVE: To assess the cost-effectiveness (CE) of an intensive lifestyle intervention (ILI) compared with standard diabetes support and education (DSE) in adults with overweight/obesity and type 2 diabetes, as implemented in the Action for Health in Diabetes study. RESEARCH DESIGN AND METHODS: Data were from 4,827 participants during their first 9 years of study participation from 2001 to 2012. Information on Health Utilities Index Mark 2 (HUI-2) and HUI-3, Short-Form 6D (SF-6D), and Feeling Thermometer (FT), cost of delivering the interventions, and health expenditures was collected during the study. CE was measured by incremental CE ratios (ICERs) in costs per quality-adjusted life year (QALY). Future costs and QALYs were discounted at 3% annually. Costs were in 2012 U.S. dollars. RESULTS: Over the 9 years studied, the mean cumulative intervention costs and mean cumulative health care expenditures were $11,275 and $64,453 per person for ILI and $887 and $68,174 for DSE. Thus, ILI cost $6,666 more per person than DSE. Additional QALYs gained by ILI were not statistically significant measured by the HUIs and were 0.07 and 0.15, respectively, measured by SF-6D and FT. The ICERs ranged from no health benefit with a higher cost based on HUIs to $96,458/QALY and $43,169/QALY, respectively, based on SF-6D and FT. CONCLUSIONS: Whether ILI was cost-effective over the 9-year period is unclear because different health utility measures led to different conclusions.

Structural attributes influencing unbound tissue distribution.

Unbound tissue-to-plasma partition coefficients (Kpuu) were determined for 56 structurally diverse compounds in rats following intravenous infusion. Five tissues were included in the study: white adipose, brain, heart, liver, and skeletal muscle. The rank ordering of the median tissue Kpuu values was: liver (4.5) > heart (1.8) > adipose (1.2) > skeletal muscle (0.6) > brain (0.05), with liver being most enriched and brain most impaired. The median Kpuu values of acids and zwitterions were lower than those of bases and neutrals in all tissues but liver. Selective tissue distribution was observed, dependent upon chemotype, which demonstrated the feasibility of targeting or restricting drug exposure in certain tissues through rational design. Physicochemical attributes for Kpuu were identified using recursive partitioning, which further classified compounds with enriched or impaired tissue distribution. The attributes identified provided valuable insight on design principles for asymmetric tissue distribution to improve efficacy or reduce toxicity.

Evaluation of Fraction Unbound Across 7 Tissues of 5 Species.

Binding to various tissues and species is frequently assessed in drug discovery and development to support safety and efficacy studies. To reduce time, cost, and labor requirements for binding experiments, we conducted a large comparison study to evaluate the correlation of fraction unbound (fu) across 7 tissues of 5 species, including white adipose, brain, heart, kidney, liver, lung, and skeletal muscle of mouse, rat, dog, monkey, and human. The results showed that there were no significant species differences of fu for tissue binding, and a single-species (e.g., rat) tissue fu can be used as a surrogate for binding in other species. Cross-tissue comparison indicated that brain, heart, liver, and muscle had quite similar fu values; rat liver binding can be used as a surrogate for binding of the other 3 tissues without any scaling factors. Binding to adipose, kidney, and lung can also be estimated with rat liver fu with scaling factors. This study suggests that a single tissue of a single species (e.g., rat liver) is a good predictor for fu of other tissues of various species with or without scaling factors. Molecular size, lipophilicity, pKa, and topological polar surface area are important physiochemical properties influencing tissue fu.

Association of Habitual Daily Physical Activity With Glucose Tolerance and ß-Cell Function in Adults With Impaired Glucose Tolerance or Recently Diagnosed Type 2 Diabetes From the Restoring Insulin Secretion (RISE) Study.

OBJECTIVE: We examined the relationship between habitual daily physical activity and measures of glucose tolerance, insulin sensitivity, and ß-cell responses in adults with impaired glucose tolerance (IGT) or drug-naive, recently diagnosed type 2 diabetes. RESEARCH DESIGN AND METHODS: Participants included 230 adults (mean ± SD age 54.5 ± 8.5 years, BMI 35 ± 5.5 kg/m2; 42.6% women) who underwent a 3-h oral glucose tolerance test (OGTT) and hyperglycemic clamp. Wrist accelerometers worn for 7 consecutive days measured total physical activity counts (TAC) (daily mean 233,460 [∼50th percentile for age]). We evaluated whether TAC was associated with fasting plasma glucose, OGTT 2-h plasma glucose or glucose incremental area under the curve (G-iAUC), hyperglycemic clamp measures of insulin sensitivity (steady-state glucose infusion rate/insulin [M/I]) and ß-cell responses (acute C-peptide response to glucose, steady-state C-peptide, and maximal ß-cell response), and OGTT C-peptide index (ΔC-peptide0-30/Δglucose0-30). RESULTS: After adjustments for confounders, there was no association of TAC with fasting plasma glucose, 2-h glucose, or G-iAUC. Higher TAC was associated with higher insulin sensitivity (M/I). After adjusting for M/I, higher TAC was not associated with measures of ß-cell response. CONCLUSIONS: In adults with IGT or drug-naive, recently diagnosed type 2 diabetes, higher levels of habitual physical activity are associated with higher insulin sensitivity. Further studies are needed to understand why higher levels of physical activity are not associated with better ß-cell response.

A Novel Unified Approach to Predict Human Hepatic Clearance for Both Enzyme- and Transporter-Mediated Mechanisms Using Suspended Human Hepatocytes.

The accurate prediction of human pharmacokinetics is critically important in modern drug discovery since it drives both pharmacological and toxicological effects. Although significant progress has been made in predicting drug disposition by hepatic drug-metabolizing enzymes, predicting transporter-mediated clearance is still highly uncertain. Furthermore, different approaches are often used to predict clearance with and without transporter involvement, hence the major clearance pathway for a compound must first be determined to know which approach to use. As a result of these challenges, a novel unified method has been developed using cryopreserved suspended human hepatocytes to predict human hepatic clearance for both enzyme- and transporter-mediated mechanisms. This method hypothesizes that, once in vitro metabolic stability is scaled by partition coefficients between hepatocytes and buffer with 4% bovine serum albumin, in vivo clearance can be better predicted. With this method, good in vitro-in vivo correlation of human hepatic clearance has been obtained for a set of 32 structurally diverse compounds, including such transporters as organic anion-transporting polypeptide substrates. The clearance predictions for most compounds are within 3-fold of observed values. This is the first time that multiple compounds result in good in vitro-in vivo extrapolation using an entirely "bottom-up" approach without any empirical scaling factor when transporter-mediated clearance is involved. Potential exceptions are compounds with significant biliary and/or extra-hepatic clearance. The method offers an alternative approach to more accurately predict human hepatic clearance when multiple complex mechanisms are involved.

Metabolism and excretion of (S)-6-(3-cyclopentyl-2-(4-trifluoromethyl)-1H-imidazol-1-yl)propanamido)nicotinic acid (PF-04991532), a hepatoselective glucokinase activator, in humans: confirmation of the MIST potential noted in first-in-Human metabolite scouting studies.

1. The absorption, metabolism, and excretion of a single oral 450-mg dose of [14C]-(S)-6-(3-cyclopentyl-2-(4-trifluoromethyl)-1H-imidazol-1-yl)propanamido)nicotinic acid (PF-04991532), a hepatoselective glucokinase activator, was investigated in humans. Mass balance was achieved with ∼94.6% of the administered dose recovered in urine and feces. The total administered radioactivity excreted in feces and urine was 70.6% and 24.1%, respectively. Unchanged PF-04991532 collectively accounted for ∼47.2% of the dose excreted in feces and urine, suggestive of moderate metabolic elimination in humans. 2. The biotransformation pathways involved acyl glucuronidation (M1), amide bond hydrolysis (M3), and CYP3A4-mediated oxidative metabolism on the cyclopentyl ring in PF-04991532 yielding monohydroxylated isomers (M2a-d). Unchanged PF-04991532 was the major circulating component (64.4% of total radioactivity) whereas M2a-d collectively represented 28.9% of the total plasma radioactivity. 3. Metabolites M2a-d were not detected systemically in rats and dogs, the preclinical species for the toxicological evaluation of PF-04991532. In contrast, cynomologus monkeys dosed orally with unlabeled PF-04991532 revealed M2a-d in circulation, whose UV abundance was comparable to the profile in humans. This observation suggested that monkeys could potentially serve as a non-rodent alternative for studying the toxicity of PF-04991532 and its metabolites M2a-d. 4. The present results are in excellent agreement with our previously generated metabolite scouting data, which provided preliminary evidence for the disproportionate metabolism of PF-04991532 in humans.

Discovery of a Novel Small-Molecule Modulator of C-X-C Chemokine Receptor Type 7 as a Treatment for Cardiac Fibrosis.

C-X-C chemokine receptor type 7 (CXCR7) is involved in cardiac and immune pathophysiology. We report the discovery of a novel 1,4-diazepine CXCR7 modulator, demonstrating for the first time the role of pharmacological CXCR7 intervention in cardiac repair. Structure-activity-relationship (SAR) studies demonstrated that a net reduction in lipophilicity (log D) and an incorporation of saturated ring systems yielded compounds with good CXCR7 potencies and improvements in oxidative metabolic stability in human-liver microsomes (HLM). Tethering an ethylene amide further improved the selectivity profile (e.g., for compound 18, CXCR7 Ki = 13 nM, adrenergic α 1a Kb > 10 000 nM, and adrenergic ß 2 Kb > 10 000 nM). The subcutaneous administration of 18 in mice led to a statistically significant increase in circulating concentrations of plasma stromal-cell-derived factor 1α (SDF-1α) of approximately 2-fold. Chronic dosing of compound 18 in a mouse model of isoproterenol-induced cardiac injury further resulted in a statistically significant reduction of cardiac fibrosis.

Liver-Targeted Small-Molecule Inhibitors of Proprotein Convertase Subtilisin/Kexin Type 9 Synthesis.

Targeting of the human ribosome is an unprecedented therapeutic modality with a genome-wide selectivity challenge. A liver-targeted drug candidate is described that inhibits ribosomal synthesis of PCSK9, a lipid regulator considered undruggable by small molecules. Key to the concept was the identification of pharmacologically active zwitterions designed to be retained in the liver. Oral delivery of the poorly permeable zwitterions was achieved by prodrugs susceptible to cleavage by carboxylesterase 1. The synthesis of select tetrazole prodrugs was crucial. A cell-free in vitro translation assay containing human cell lysate and purified target mRNA fused to a reporter was used to identify active zwitterions. In vivo PCSK9 lowering by oral dosing of the candidate prodrug and quantification of the drug fraction delivered to the liver utilizing an oral positron emission tomography 18 F-isotopologue validated our liver-targeting approach.

Discovery of Potent and Orally Bioavailable Macrocyclic Peptide-Peptoid Hybrid CXCR7 Modulators.

The chemokine receptor CXCR7 is an attractive target for a variety of diseases. While several small-molecule modulators of CXCR7 have been reported, peptidic macrocycles may provide advantages in terms of potency, selectivity, and reduced off-target activity. We produced a series of peptidic macrocycles that incorporate an N-linked peptoid functionality where the peptoid group enabled us to explore side-chain diversity well beyond that of natural amino acids. At the same time, theoretical calculations and experimental assays were used to track and reduce the polarity while closely monitoring the physicochemical properties. This strategy led to the discovery of macrocyclic peptide-peptoid hybrids with high CXCR7 binding affinities (Ki < 100 nM) and measurable passive permeability (Papp > 5 × 10-6 cm/s). Moreover, bioactive peptide 25 (Ki = 9 nM) achieved oral bioavailability of 18% in rats, which was commensurate with the observed plasma clearance values upon intravenous administration.

Novel Method to Predict In Vivo Liver-to-Plasma Kpuu for OATP Substrates Using Suspension Hepatocytes.

The ability to predict human liver-to-plasma unbound partition coefficient (Kpuu) is of great importance to estimate unbound liver concentration, develop PK/PD relationships, predict efficacy and toxicity in the liver, and model the drug-drug interaction potential for drugs that are asymmetrically distributed into the liver. A novel in vitro method has been developed to predict in vivo Kpuu with good accuracy using cryopreserved suspension hepatocytes in InVitroGRO HI media with 4% BSA. Validation was performed using six OATP substrates with rat in vivo Kpuu data from i.v. infusion studies where a steady state was achieved. Good in vitro-in vivo correlation (IVIVE) was observed as the in vitro Kpuu values were mostly within 2-fold of in vivo Kpuu Good Kpuu IVIVE in human was also observed with in vivo Kpuu data of dehydropravastatin from positron emission tomography and in vivo Kpuu data from PK/PD modeling for pravastatin and rosuvastatin. Under the specific Kpuu assay conditions, the drug-metabolizing enzymes and influx/efflux transporters appear to function at physiologic levels. No scaling factors are necessary to predict in vivo Kpuu from in vitro data. The novel in vitro Kpuu method provides a useful tool in drug discovery to project in vivo Kpuu.

Efficient Liver Targeting by Polyvalent Display of a Compact Ligand for the Asialoglycoprotein Receptor.

A compact and stable bicyclic bridged ketal was developed as a ligand for the asialoglycoprotein receptor (ASGPR). This compound showed excellent ligand efficiency, and the molecular details of binding were revealed by the first X-ray crystal structures of ligand-bound ASGPR. This analogue was used to make potent di- and trivalent binders of ASGPR. Extensive characterization of the function of these compounds showed rapid ASGPR-dependent cellular uptake in vitro and high levels of liver/plasma selectivity in vivo. Assessment of the biodistribution in rodents of a prototypical Alexa647-labeled trivalent conjugate showed selective hepatocyte targeting with no detectable distribution in nonparenchymal cells. This molecule also exhibited increased ASGPR-directed hepatocellular uptake and prolonged retention compared to a similar GalNAc derived trimer conjugate. Selective release in the liver of a passively permeable small-molecule cargo was achieved by retro-Diels-Alder cleavage of an oxanorbornadiene linkage, presumably upon encountering intracellular thiol. Therefore, the multicomponent construct described here represents a highly efficient delivery vehicle to hepatocytes.