Primate Model Carrying LMNA Mutation Develops Dilated Cardiomyopathy

To solve the clinical transformation dilemma of lamin A/C (LMNA)-mutated dilated cardiomyopathy (LMD), we developed an LMNA-mutated primate model based on the similarity between the phenotype of primates and humans. We screened out patients with LMD and compared the clinical data of LMD with TTN-mutated and mutation-free dilated cardiomyopathy to obtain the unique phenotype. After establishment of the LMNA c.357-2A>G primate model, primates were continuously observed for 48 months, and echocardiographic, electrophysiological, histologic, and transcriptional data were recorded. The LMD primate model was found to highly simulate the phenotype of clinical LMD. In addition, the LMD primate model shared a similar natural history with humans.

A Heterozygous Phospholamban Variant (p.R14del) Leads to Left Ventricular Involvement and Heart Failure Phenotypes in Arrhythmogenic Right Ventricular Cardiomyopathy

This study aimed to determine the prevalence and clinical features of Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) caused by pathogenic mutations in the Phospholamban (PLN) gene. The study included 170 patients who had a confirmed diagnosis of ARVC and underwent PLN genetic screening using next-generation sequencing. The findings of this study provide valuable insights into the association between PLN mutations and ARVC, which can aid in the development of more effective diagnostic and treatment strategies for ARVC patients. Out of the patients evaluated, six had a rare pathogenic mutation in PLN with the same p.R14del variant. Family screening revealed that heterozygous carriers of p.R14del exhibited a definite ARVC phenotype. In clinical studies, individuals with the p.R14del mutation experienced a similar rate of malignant arrhythmia events as those with classic desmosome mutations. After adjusting for covariates, individuals with PLN mutations had a two point one seven times greater likelihood of experiencing transplant-related risks compared to those who did not possess PLN mutations (95% CI 1.08-6.82, p = 0.035). The accumulation of left ventricular fat and fibers is a pathological marker for ARVC patients with p.R14del mutations. In a cohort of 170 Chinese ARVC patients, three point five percent of probands had the PLN pathogenic variant (p.R14del) and all were female. Our data shows that PLN-related ARVC patients are at high risk for ventricular arrhythmias and heart failure, which requires clinical differentiation from classic ARVC. Furthermore, carrying the p.R14del mutation can be an independent prognostic risk factor in ARVC patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43657-023-00126-w.

Single-cell RNA sequencing in donor and end-stage heart failure patients identifies NLRP3 as a therapeutic target for arrhythmogenic right ventricular cardiomyopathy

BACKGROUND

Dilation may be the first right ventricular change and accelerates the progression of threatening ventricular tachyarrhythmias and heart failure for patients with arrhythmogenic right ventricular cardiomyopathy (ARVC), but the treatment for right ventricular dilation remains limited.

METHODS

Single-cell RNA sequencing (scRNA-seq) of blood and biventricular myocardium from 8 study participants was performed, including 6 end-stage heart failure patients with ARVC and 2 normal controls. ScRNA-seq data was then deeply analyzed, including cluster annotation, cellular proportion calculation, and characterization of cellular developmental trajectories and interactions. An integrative analysis of our single-cell data and published genome-wide association study-based data provided insights into the cell-specific contributions to the cardiac arrhythmia phenotype of ARVC. Desmoglein 2 (Dsg2)mut/mut mice were used as the ARVC model to verify the therapeutic effects of pharmacological intervention on identified cellular cluster.

RESULTS

Right ventricle of ARVC was enriched of CCL3+ proinflammatory macrophages and TNMD+ fibroblasts. Fibroblasts were preferentially affected in ARVC and perturbations associated with ARVC overlap with those reside in genetic variants associated with cardiac arrhythmia. Proinflammatory macrophages strongly interact with fibroblast. Pharmacological inhibition of Nod-like receptor protein 3 (NLRP3), a transcriptional factor predominantly expressed by the CCL3+ proinflammatory macrophages and several other myeloid subclusters, could significantly alleviate right ventricular dilation and dysfunction in Dsg2mut/mut mice (an ARVC mouse model).

CONCLUSIONS

This study provided a comprehensive analysis of the lineage-specific changes in the blood and myocardium from ARVC patients at a single-cell resolution. Pharmacological inhibition of NLRP3 could prevent right ventricular dilation and dysfunction of mice with ARVC.

Acceptor engineering-facilitated versatile AIEgen for mitochondria-targeted multimodal imaging-guided cancer photoimmunotherapy

Photoimmunotherapy has been acknowledged to be an unprecedented strategy to obtain significantly improved cancer treatment efficacy. In this regard, the exploitation of high-performance multimodal phototheranostic agents is highly desired. Apart from tailoring electron donors, acceptor engineering is gradually rising as a deliberate approach in this field. Herein, we rationally designed a family of aggregation-induced emission (AIE)-active compounds with the same donors but different acceptors based on the acceptor engineering. Through finely adjusting the functional groups on electron acceptors, the electron affinity of electron acceptors and the conformation of the compounds were simultaneously modulated. It was found that one of the molecules (named DCTIC), bearing a moderately electrophilic electron acceptor and the best planarity, exhibited optimal phototheranostic properties in terms of light-harvesting ability, fluorescence emission, reactive oxygen species (ROS) production, and photothermal performance. For the purpose of amplified therapeutic outcomes, DCTIC was fabricated into tumor and mitochondria dual-targeted DCTIC nanoparticles (NPs), which afforded good performance in the fluorescence/photoacoustic/photothermal trimodal imaging-guided photodynamic/photothermal-synergized cancer immunotherapy with the combination of programmed cell death protein-1 (PD-1) antibody. Not only the primary tumors were totally eradicated, but efficient growth inhibition of distant tumors was also realized.

STING regulates the transformation of the proinflammatory macrophage phenotype by HIF1A into autoimmune myocarditis

Macrophages play an essential role in the pathogenesis of autoimmune myocarditis, but the molecular mechanism remains largely unknown. Here, the role of Stimulator of interferon gene (Sting) in autoimmune myocarditis was investigated. Six-week-old male BALB/c mice received two subcutaneous injections of 250 μg α-MyHC peptide to establish experimental autoimmune myocarditis (EAM). With single-cell RNA sequencing analysis of cardiac immune (Cd45+) cells, Sting was found to initiate proinflammatory macrophage differentiation related to the acute EAM phase. Furthermore, proinflammatory macrophages contribute to the pathogenesis of EAM via hypoxia-inducible factor-1α (Hif1α). A higher expression level of Sting was detected in macrophages from myocarditis, which was positively correlated with Hif1α expression. Single-stranded DNA (ssDNA) accumulation in macrophages in myocarditis was observed in the hearts of EAM mice. Pharmacological blockade of STING by C-176 (a specific inhibitor) ameliorated the inflammatory response of EAM and reduced proinflammatory molecule (Ifn-β, Tnf-α, Ccl2, and F4/80) expression and Hif1α expression. In vitro studies revealed that ssDNA activated the expression of Sting; in turn, Sting accelerated proinflammatory molecule expression in mouse macrophages. Inhibition of Hif1α expression could reduce Sting-associated cardiac inflammation and proinflammatory molecule expression. In addition, the expression of STING and ssDNA accumulation in macrophages were observed in human autoimmune myocarditis heart samples. STING activated proinflammatory macrophage via HIF1A, promoting the development of autoimmune myocarditis. The STING signaling pathway might provide a novel mechanism of autoimmune myocarditis and serve as a potential therapeutic target for autoimmune myocarditis patients.

Fiber Optic Sensing Technology and Vision Sensing Technology for Structural Health Monitoring

Structural health monitoring is currently a crucial measure for the analysis of structural safety. As a structural asset management approach, it can provide a cost-effective measure and has been used successfully in a variety of structures. In recent years, the development of fiber optic sensing technology and vision sensing technology has led to further advances in structural health monitoring. This paper focuses on the basic principles, recent advances, and current status of applications of these two sensing technologies. It provides the reader with a broad review of the literature. It introduces the advantages, limitations, and future directions of these two sensing technologies. In addition, the main contribution of this paper is that the integration of fiber optic sensing technology and vision sensing technology is discussed. This paper demonstrates the feasibility and application potential of this integration by citing numerous examples. The conclusions show that this new integrated sensing technology can effectively utilize the advantages of both fields.

Single-cell RNA sequencing to identify cellular heterogeneity and targets in cardiovascular diseases: from bench to bedside

The mechanisms of cardiovascular diseases (CVDs) remain incompletely elucidated. Single-cell RNA sequencing (scRNA-seq) has enabled the profiling of single-cell transcriptomes at unprecedented resolution and throughput, which is critical for deciphering cardiovascular cellular heterogeneity and underlying disease mechanisms, thereby facilitating the development of therapeutic strategies. In this review, we summarize cellular heterogeneity in cardiovascular homeostasis and diseases as well as the discovery of potential disease targets based on scRNA-seq, and yield new insights into the promise of scRNA-seq technology in precision medicine and clinical application.

The effect of SNPs in lncRNA as ceRNA on the risk and prognosis of hepatocellular carcinoma

Background

Most susceptible loci of hepatocellular carcinoma (HCC) identified by genome-wide association studies (GWAS) are located in non-coding regions, and the mechanism of action remains unclear. The objective of this study was to explore the association of single nucleotide polymorphisms (SNPs) on long non-coding RNAs (lncRNAs) that affect competing endogenous RNAs (ceRNA) regulation mechanism with the risk and prognosis of HCC.

Methods

Based on a set of bioinformatics strategies, eight lncRNA genes that affect HCC through the mechanism of lncRNA-mediated ceRNA were systematically screened, and 15 SNPs that affect microRNA (miRNA) binding in these lncRNA genes were annotated. Genotyping was performed in 800 HCC cases and 801 healthy controls to examine associations of these SNPs with HCC in a northeastern Chinese Han population.

Results

The GG, GC and GG + GC genotypes of HOTAIR rs7958904 were associated with a 0.65, 0.59 and 0.63-fold decreased HCC risk, respectively. In addition, HCC patients with PVT1 rs3931282 AA + GA genotypes were less prone to develop late-stage cancers in a stratified analysis of clinical characteristics. When stratified by clinical biochemical indexes, rs1134492 and rs10589312 in PVT1 and rs84557 in EGFR-AS1 showed significant associations with aspartate aminotransferase (AST), alanine aminotransferase (ALT) or AST/ALT ratio in HCC patients. Furthermore, we constructed potential ceRNA regulatory axes that might be affected by five positive SNPs to explain the causes of these genetic associations.

Conclusions

HOTAIR rs7958904, PVT1 rs3931282, rs1134492 and rs10589312, and EGFR-AS1 rs84557 might be predictors for HCC risk or prognosis. Our results provide new insights into how SNPs on lncRNA-mediated ceRNAs confer interindividual differences to occurrence and progression of HCC.

N-Acetylcysteine, an ROS Inhibitor, Alleviates the Pathophysiology of Hyperthyroidism-Induced Cardiomyopathy via the ROS/Ca2+ Pathway

Hyperthyroidism is common and can induce cardiomyopathy, but there is no effective therapeutic strategy. The purpose of this study was to investigate the molecular mechanism of hyperthyroidism-induced cardiomyopathy (HTC) and the effect of N-acetylcysteine (NAC), an ROS inhibitor, on the pathophysiology of HTC in vivo and in vitro. Compared with those in the control groups in vivo and in vitro, TT3 and TT4 were significantly increased, the structure of myocardial cells was enlarged and disordered, and interstitial fibrosis and the apoptosis of myocardial cells were markedly increased in the L-Thy group. The ROS and inflammatory response were increased in the hyperthyroidism group. In the NAC group, the contents of TT3 and TT4 were decreased, the myocardial cell structure was slightly disturbed, fibrosis and apoptosis were significantly reduced, and the ROS level and inflammatory response were significantly reduced. Interestingly, L-Thy decreased the viability of fibroblasts and H9c2 cells, suggesting that L-Thy-induced fibrosis was not caused by the proliferation of fibroblasts. The molecular mechanism of HTC could be explained by the fact that L-Thy could cause cardiac hypertrophy, inflammation, and fibrosis by regulating the Ca2+/calpain/Rcan1-dependent signalling pathway, the Ca2+/Rcan1/NF-κB/p65-dependent signalling pathway, and the Ca2+/ROS/Bcl-2/caspase-3-dependent signalling pathway. In conclusion, NAC can alleviate the pathophysiology of hyperthyroidism-induced cardiomyopathy, probably by regulating the ROS/Ca2+-dependent pathway.

Age-related memory vulnerability to interfering stimuli is caused by gradual loss of MAPK-dependent protection in Drosophila

Age‐related memory impairment (AMI) is a common phenomenon across species. Vulnerability to interfering stimuli has been proposed to be an important cause of AMI. However, the molecular mechanisms underlying this vulnerability‐related AMI remain unknown. Here we show that learning‐activated MAPK signals are gradually lost with age, leading to vulnerability‐related AMI in Drosophila. Young flies (2‐ or 3‐day‐old) exhibited a significant increase in phosphorylated MAPK levels within 15 min after learning, whereas aged flies (25‐day‐old) did not. Compared to 3‐day‐old flies, significant 1 h memory impairments were observed in 15‐, 20‐, and 30‐day‐old flies, but not in 10‐day‐old flies. However, with post‐learning interfering stimuli such as cooling or electric stimuli, 10‐day‐old flies had worse memory performance at 1 h than 3‐day‐old flies, showing a premature AMI phenomenon. Increasing learning‐activated MAPK signals through acute transgene expression in mushroom body (MB) neurons restored physiological trace of 1 h memory in a pair of MB output neurons in aged flies. Decreasing such signals in young flies mimicked the impairment of 1 h memory trace in aged flies. Restoring learning‐activated MAPK signals in MB neurons in aged flies significantly suppressed AMI even with interfering stimuli. Thus, our data suggest that age‐related loss of learning‐activated neuronal MAPK signals causes memory vulnerability to interfering stimuli, thereby leading to AMI.

In Vivo Dopamine Neuron Imaging-Based Small Molecule Screen Identifies Novel Neuroprotective Compounds and Targets

Parkinson’s disease (PD) is the second most common neurodegenerative disorder with prominent dopamine (DA) neuron degeneration. PD affects millions of people worldwide, but currently available therapies are limited to temporary relief of symptoms. As an effort to discover disease-modifying therapeutics, we have conducted a screen of 1,403 bioactive small molecule compounds using an in vivo whole organism screening assay in transgenic larval zebrafish. The transgenic model expresses the bacterial enzyme nitroreductase (NTR) driven by the tyrosine hydroxylase (th) promotor. NTR converts the commonly used antibiotic pro-drug metronidazole (MTZ) to the toxic nitroso radical form to induce DA neuronal loss. 57 compounds were identified with a brain health score (BHS) that was significantly improved compared to the MTZ treatment alone after FDR adjustment (padj<0.05). Independently, we curated the high throughput screening (HTS) data by annotating each compound with pharmaceutical classification, known mechanism of action, indication, IC50, and target. Using the Reactome database, we performed pathway analysis, which uncovered previously unknown pathways in addition to validating previously known pathways associated with PD. Non-topology-based pathway analysis of the screening data further identified apoptosis, estrogen hormone, dipeptidyl-peptidase 4, and opioid receptor Mu1 to be potentially significant pathways and targets involved in neuroprotection. A total of 12 compounds were examined with a secondary assay that imaged DA neurons before and after compound treatment. The z’-factor of this secondary assay was determined to be 0.58, suggesting it is an excellent assay for screening. Etodolac, nepafenac, aloperine, protionamide, and olmesartan showed significant neuroprotection and was also validated by blinded manual DA neuronal counting. To determine whether these compounds are broadly relevant for neuroprotection, we tested them on a conduritol-b-epoxide (CBE)-induced Gaucher disease (GD) model, in which the activity of glucocerebrosidase (GBA), a commonly known genetic risk factor for PD, was inhibited. Aloperine, olmesartan, and nepafenac showed significant protection of DA neurons in this assay. Together, this work, which combines high content whole organism in vivo imaging-based screen and bioinformatic pathway analysis of the screening dataset, delineates a previously uncharted approach for identifying hit-to-lead candidates and for implicating previously unknown pathways and targets involved in DA neuron protection.

A zebrafish screen reveals Renin-angiotensin system inhibitors as neuroprotective via mitochondrial restoration in dopamine neurons

Parkinson’s disease (PD) is a common neurodegenerative disorder without effective disease-modifying therapeutics. Here, we establish a chemogenetic dopamine (DA) neuron ablation model in larval zebrafish with mitochondrial dysfunction and robustness suitable for high-content screening. We use this system to conduct an in vivo DA neuron imaging-based chemical screen and identify the Renin-Angiotensin-Aldosterone System (RAAS) inhibitors as significantly neuroprotective. Knockdown of the angiotensin receptor 1 (agtr1) in DA neurons reveals a cell-autonomous mechanism of neuroprotection. DA neuron-specific RNA-seq identifies mitochondrial pathway gene expression that is significantly restored by RAAS inhibitor treatment. The neuroprotective effect of RAAS inhibitors is further observed in a zebrafish Gaucher disease model and Drosophila pink1-deficient PD model. Finally, examination of clinical data reveals a significant effect of RAAS inhibitors in delaying PD progression. Our findings reveal the therapeutic potential and mechanisms of targeting the RAAS pathway for neuroprotection and demonstrate a salient approach that bridges basic science to translational medicine.

Parkinson’s disease is caused by the slow death and deterioration of brain cells, in particular of the neurons that produce a chemical messenger known as dopamine. Certain drugs can mitigate the resulting drop in dopamine levels and help to manage symptoms, but they cause dangerous side-effects. There is no treatment that can slow down or halt the progress of the condition, which affects 0.3% of the population globally.

Many factors, both genetic and environmental, contribute to the emergence of Parkinson’s disease. For example, dysfunction of the mitochondria, the internal structures that power up cells, is a known mechanism associated with the death of dopamine-producing neurons.

Zebrafish are tiny fish which can be used to study Parkinson’s disease, as they are easy to manipulate in the lab and share many characteristics with humans. In particular, they can be helpful to test the effects of various potential drugs on the condition.

Here, Kim et al. established a new zebrafish model in which dopamine-producing brain cells die due to their mitochondria not working properly; they then used this assay to assess the impact of 1,403 different chemicals on the integrity of these cells. A group of molecules called renin-angiotensin-aldosterone (RAAS) inhibitors was shown to protect dopamine-producing neurons and stopped them from dying as often. These are already used to treat high blood pressure as they help to dilate blood vessels. In the brain, however, RAAS worked by restoring certain mitochondrial processes.

Kim et al. then investigated whether these results are relevant in other, broader contexts. They were able to show that RAAS inhibitors have the same effect in other animals, and that Parkinson’s disease often progresses more slowly in patients that already take these drugs for high blood pressure.

Taken together, these findings therefore suggest that RAAS inhibitors may be useful to treat Parkinson’s disease, as well as other brain illnesses that emerge because of mitochondria not working properly. Clinical studies and new ways to improve these drugs are needed to further investigate and capitalize on these potential benefits.

Long-term memory is formed immediately without the need for protein synthesis-dependent consolidation in Drosophila

It is believed that long-term memory (LTM) cannot be formed immediately because it must go through a protein synthesis-dependent consolidation process. However, the current study uses Drosophila aversive olfactory conditioning to show that such processes are dispensable for context-dependent LTM (cLTM). Single-trial conditioning yields cLTM that is formed immediately in a protein-synthesis independent manner and is sustained over 14 days without decay. Unlike retrieval of traditional LTM, which requires only the conditioned odour and is mediated by mushroom-body neurons, cLTM recall requires both the conditioned odour and reinstatement of the training-environmental context. It is mediated through lateral-horn neurons that connect to multiple sensory brain regions. The cLTM cannot be retrieved if synaptic transmission from any one of these centres is blocked, with effects similar to those of altered encoding context during retrieval. The present study provides strong evidence that long-term memory can be formed easily without the need for consolidation.

New protein synthesis is known to be indispensable for the consolidation of long-term memory. Here, the authors report that an olfactory memory can be successfully recalled after 14 days without protein synthesis when the training context is also provided in addition to the conditioned odor.

Abstract P5-04-09: Not presented

This abstract was not presented at the conference.

Citation Format: Mo H, Wang X, Qian Z, Xu B, Ma F. Not presented [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-04-09.

[A multi-center cross-sectional survey of medicine application in patients with osteoarthritis in China]

OBJECTIVE

To investigate the clinical characteristics, the medicine application and to evaluate the disease activity in patients with osteoarthritis (OA) in China.

METHODS

This was a cross-sectional study. Totally 1 066 cases of OA from 40 hospitals in China from April to October 2017 were retrospectively enrolled. Demographic characteristics, clinical data, medicine application, and joint function were evaluated. All the data were analyzed by SPSS software 19.0. t test, Mann-Whitney U test and chi-square test were used for statistical analysis.

RESULTS

In the 1 066 cases, the male-to-female ratio was 1:3.6 and the average age was (61.9±11.0) years, with an age range from 36 to 94 years. The incidence of knee OA, hip OA, and hand OA were respectively 81.9% (873/1 066), 14.1% (150/1 066), and 36.3% (387/1 066). In the study, 242 (22.7%) cases had two kinds of joint areas involved and three joint areas were involved in 51 cases (4.8%), and 56.6% (603/1 066) of the patients used more than one kind of non-steroid anti-inflammatory drugs (NSAIDs) while 61.2% (652/1 066) used disease modifying osteoarthritis drugs (DMOADs), including glucosamine (37.5%, 400/1 066), chondroitin sulfate (2.0%, 21/1 066), diacetate (5.9%, 63/1 066), and the combination of these drugs (15.8%, 168/1 066). 8.6% (92/1 066) patients only took analgesics to relieve the pain, not using any kind of NSAIDs or DMOADs. And 232 patients (21.7%) had intra-articular injections, including 9.2% (98/1 066) sodium hyaluronate, 4.5%(48/1 066) glucocorticoid, and 8.1% (86/1 066) combination of the two drugs. The proportion of the patients taking topical drugs accounted for 26.5% (283/1 066) and physical therapy accounted for 15.8% (168/1 066). Compared with those who suffered from knee OA, the patients who suffered from hip OA had more severe disease assessment. Moreover, there were significant differences in pain (Z=-7.625, P<0.001), morning stiffness (Z=-6.229, P<0.001), and joint function (Z=-6.777, P<0.001) between the two groups of the patients who suffered from knee or hip OA with The Western Ontario and McMaster Universities (WOMAC) osteoarthritis index. Furthermore, patients with hip OA took more analgesics (χ²=24.838, P<0.001).

CONCLUSION

Oral NSAIDs and DMOADs are wildly used in patients with OA in China. However, the treatment of some patients still need to be improved. Patients with hip OA are more seriously ill and require aggressive treatment.

Clopidogrel may decrease the risk of post-stroke infection after ischaemic stroke

BACKGROUND AND PURPOSE

The P2Y12 receptor, a well-known factor in the platelet activation pathway, plays a role in thrombosis as well as systemic inflammation. Clopidogrel, a prototype P2Y12 receptor antagonist, reportedly decreases inflammation and systemic infection. The aim of this study was to evaluate whether clopidogrel use decreases the risk of post-stroke infection following ischaemic stroke.

METHODS

A total of 1643 patients with acute ischaemic stroke (within 7 days after onset) were included for analysis between March 2010 and December 2015. Patients were categorized into two groups (clopidogrel users versus clopidogrel non-users), and clinical characteristics and risks of post-stroke infection were compared between the two groups. The inverse probability of treatment weighting using propensity scores for baseline imbalance adjustments was applied.

RESULTS

Of the included patients (mean age 67.7 years; men 60.6%), 670 (40.8%) patients were clopidogrel users and 164 (10.0%) patients had post-stroke infection. The proportion of patients with post-stroke infection was significantly lower in clopidogrel users compared to clopidogrel non-users (6.7% vs. 12.2%, P ≤ 0.001). Moreover, clopidogrel users were less likely to be admitted to the intensive care unit (13.3% vs. 35.3%, P = 0.006). A multivariate analysis with inverse probability of treatment weighting revealed that clopidogrel users exhibited a lower risk of post-stroke infection (odds ratio 0.56, 95% confidence interval 0.42-0.75) and intensive care unit admission (odds ratio 0.34, 95% confidence interval 0.22-0.53).

CONCLUSIONS

The study suggested that clopidogrel users exhibit a lower risk of infection and develop less severe infections after ischaemic stroke. Further prospective studies are needed.

Tocotrienol supplementation suppressed bone resorption and oxidative stress in postmenopausal osteopenic women: a 12-week randomized double-blinded placebo-controlled trial

Tocotrienols have shown bone-protective effect in animals. This study showed that a 12-week tocotrienol supplementation decreased concentrations of bone resorption biomarker and bone remodeling regulators via suppressing oxidative stress in postmenopausal osteopenic women.

INTRODUCTION

Tocotrienols (TT) have been shown to benefit bone health in ovariectomized animals, a model of postmenopausal women. The purpose of this study was to evaluate the effect of 12-week TT supplementation on bone markers (serum bone-specific alkaline phosphatase (BALP), urine N-terminal telopeptide (NTX), serum soluble receptor activator of nuclear factor-kappaB ligand (sRANKL), and serum osteoprotegerin (OPG)), urine calcium, and an oxidative stress biomarker (8-hydroxy-2'-deoxyguanosine (8-OHdG)) in postmenopausal women with osteopenia.

METHODS

Eighty-nine postmenopausal osteopenic women (59.7 ± 6.8 year, BMI 28.7 ± 5.7 kg/m²) were randomly assigned to three groups: (1) placebo (430 mg olive oil/day), (2) low TT (430 mg TT/day, 70% purity), and (3) high TT (860 mg TT/day, 70% purity). TT, an extract from annatto seed with 70% purity, consisted of 90% delta-TT and 10% gamma-TT. Overnight fasting blood and urine samples were collected at baseline, 6, and 12 weeks for biomarker analyses. Eighty-seven subjects completed the 12-week study.

RESULTS

Relative to the placebo group, there were marginal decreases in serum BALP level in the TT-supplemented groups over the 12-week study period. Significant decreases in urine NTX levels, serum sRANKL, sRANKL/OPG ratio, and urine 8-OHdG concentrations and a significant increase in BALP/NTX ratio due to TT supplementation were observed. TT supplementation did not affect serum OPG concentrations or urine calcium levels throughout the study period. There were no significant differences in NTX level, BALP/NTX ratio, sRANKL level, and sRANKL/OPG ratio between low TT and high TT groups.

CONCLUSIONS

Twelve-week annatto-extracted TT supplementation decreased bone resorption and improved bone turnover rate via suppressing bone remodeling regulators in postmenopausal women with osteopenia. Such osteoprotective TT's effects may be, in part, mediated by an inhibition of oxidative stress.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02058420.

TITLE

Tocotrienols and bone health of postmenopausal women.

Intrapatient viral diversity and treatment outcome in patients with genotype 3a hepatitis C virus infection on sofosbuvir-containing regimens

Treatment with the direct-acting antiviral agent (DAA) sofosbuvir (SOF), an NS5B inhibitor, and velpatasvir (VEL), an NS5A inhibitor, demonstrates viral cure rates of ≥95% in hepatitis C virus (HCV) genotypes (GT) 1-6. Here, we investigated intrapatient HCV diversity in NS5A and NS5B using Shannon entropy to examine the relationship between viral diversity and treatment outcome. At baseline, HCV diversity was lowest in patients infected with HCV GT3 as compared to the other GTs, and viral diversity was greater in NS5A than NS5B (P < .0001). Treatment outcome with SOF/VEL or the comparator regimen of SOF with ribavirin (RBV) was not correlated with baseline diversity. However, among persons treated with SOF/VEL, a decrease in diversity from baseline was observed at relapse in the majority virologic failures, consistent with a viral bottleneck event at relapse. In contrast, an increase in diversity was observed in 27% of SOF+RBV virologic failures. We investigated whether the increase in diversity was due to an increase in the transition rate, one mode of potential RBV-mediated mutagenesis; however, we found no evidence of this mechanism. Overall, we did not observe that viral diversity at baseline influenced treatment outcome, but the diversity changes observed at relapse can improve our understanding of RBV viral suppression in vivo.

Resistance characterization of ledipasvir and velpatasvir in hepatitis C virus genotype 4

HCV genotype 4 (GT4) has often been overlooked in drug development, even though it infects ~20 million people worldwide. Ledipasvir/sofosbuvir and sofosbuvir/velpatasvir were highly efficacious in GT4 HCV-infected patients from GS-US-337-1119 and GS-US-342-1138. Here, we characterize the resistance profile of ledipasvir (LDV) and velpatasvir (VEL) in patients with GT4 HCV infection. NS5A deep-sequencing was performed for 454 patients infected with HCV GT4 at baseline, including 44 patients enrolled in GS-US-337-1119 and 116 patients enrolled in GS-US-342-1138, and at relapse for patients with virologic failure. LDV and VEL susceptibilities of 56 patient isolates were determined. In GS-US-337-1119, SVR12 rates were 100% for all subtypes except 4b and 4r. Phenotypic assessment of 56 HCV NS5A patient isolates from various GT4 subtypes indicated that LDV had high potency for the common subtypes 4a/d, and subtypes 4c/f/k/l/m/n/o/p/r/t despite the presence of resistance-associated substitutions (RASs). For the rare GT4b, LDV median EC₅₀ was higher, but with a broad range of individual values. Importantly, all GT4b isolates tested had 2-4 NS5A RASs, some including Y93H. Similarly, the 2 GT4r infected patients who had virologic relapse had rare triple RASs. Reversion of these substitutions to the consensus residue significantly increased LDV susceptibility. In GS-US-342-1138, all patients achieved SVR12, regardless of their subtype or presence of RASs. In vitro data confirmed that VEL is potent against all GT4 isolates tested. LDV and VEL are potent antiviral drugs, estimated to be effective against >95% and >99%, respectively, of GT4 HCV isolates.

Nonstructural protein 5A resistance profile in patients with chronic hepatitis C treated with ledipasvir-containing regimens without sofosbuvir

The study aimed to evaluate the effects of baseline hepatitis C virus (HCV) nonstructural protein 5A (NS5A) resistance-associated substitutions (RASs) on sustained virologic response to ledipasvir (LDV)-containing regimens in the absence of sofosbuvir (SOF) in patients with HCV genotype (GT) 1 infection across 6 phase 2 clinical studies. We analysed data from 1103 patients who received either LDV + vedroprevir (NS3 protease inhibitor) + tegobuvir (NS5B inhibitor) ± ribavirin or LDV + ribavirin + pegylated interferon. Population sequencing of HCV NS5A was performed at baseline and at virologic failure from patient plasma samples. Of 1045 patients with available baseline sequences, 747 (67.7%) had GT1a, and 298 (26.9%) had GT1b infection. The overall prevalence of NS5A RASs at baseline was 9.4%; 7.6% (57/747) and 13.8% (41/298) of patients with GT1a and GT1b infection, respectively. The majority of GT1a-infected patients with NS5A RASs at baseline had a single NS5A RAS (78.9%) at NS5A positions K24R, M28T, Q30H/L, L31M and Y93H/N/C/S. The spectrum of NS5A RASs detected in GT1b patients was much less diverse compared to GT1a patients, with all patients harbouring a single NS5A RAS either L31M or Y93H/C. For patients treated with LDV-containing regimens in the absence of SOF, the presence of baseline NS5A RASs was associated with low SVR rates. In patients with virologic failure, nearly all had either pre-existing and/or emergent NS5A RASs: 287/287 (100%) and 40/42 (95.2%) patients with GT1a and GT1b infection, respectively. Three novel NS5A substitutions were identified as emergent NS5A RASs: K26E and S38F in GT1a; and L31I in GT1b. In conclusion, the presence of NS5A RASs at baseline reduced the SVR rate in patients treated with LDV in combination vedroprevir + tegobuvir ± ribavirin or ribavirin + pegylated interferon. Virologic failure was associated with the detection of NS5A RASs in nearly all patients. These results suggest that the resistance barrier may differ depending on HCV drug combination and may be more important than that of the individual DAAs.

A High-Content Larval Zebrafish Brain Imaging Method for Small Molecule Drug Discovery

Drug discovery in whole-organisms such as zebrafish is a promising approach for identifying biologically-relevant lead compounds. However, high content imaging of zebrafish at cellular resolution is challenging due to the difficulty in orienting larvae en masse such that the cell type of interest is in clear view. We report the development of the multi-pose imaging method, which uses 96-well round bottom plates combined with a standard liquid handler to repose the larvae within each well multiple times, such that an image in a specific orientation can be acquired. We have validated this method in a chemo-genetic zebrafish model of dopaminergic neuron degeneration. For this purpose, we have developed an analysis pipeline that identifies the larval brain in each image and then quantifies neuronal health in CellProfiler. Our method achieves a SSMD* score of 6.96 (robust Z’-factor of 0.56) and is suitable for screening libraries up to 10⁵ compounds in size.

Resistance Analyses of Japanese Hepatitis C-Infected Patients Receiving Sofosbuvir or Ledipasvir/Sofosbuvir Containing Regimens in Phase 3 Studies

High rates of sustained virologic response (SVR) has been achieved in Japanese patients with chronic hepatitis C virus (HCV) genotype (GT)1 and GT2 infection treated with ledipasvir/sofosbuvir (LDV/SOF) ±ribavirin (RBV) and SOF+RBV, respectively. We evaluated the effect of baseline HCV NS5A and NS5B resistance-associated variants (RAVs) on treatment outcome and characterized variants at virologic failure. Baseline deep sequencing for NS5A and NS5B genes was performed for all GT1 patients. Deep sequencing of NS5A (GT1 only) and NS5B (GT1 and GT2) was performed for patients who failed treatment or discontinued early with detectable HCV RNA (i.e., >25 IU/mL). In patients with HCV GT1 infection, 22.3% (GT1a: 2/11; GT1b: 74/330) had ≥1 baseline NS5A RAV. The most frequent NS5A RAVs in GT1b were Y93H (17.9%, 59/330) and L31M (2.4%, 8/330). Despite the presence of NS5A RAVs at baseline, 100% and 97% of patients achieved SVR12, compared with 100% and 99% for those with no NS5A RAVs with LDV/SOF and LDV/SOF+RBV, respectively. All patients with NS5B RAVs at baseline achieved SVR12. Of the 153 patients with GT2 infection (GT2a 60.1%, GT2b 39.9%), 3.3% (5/153) experienced viral relapse. No S282T or other NS5B RAVs were detected at baseline or relapse; no change in susceptibility to SOF or RBV was observed at relapse. In conclusion, LDV/SOF and SOF+RBV demonstrate a high barrier to resistance in Japanese patients with HCV GT1 and GT2 infection. The presence of baseline NS5A RAVs did not impact treatment outcome in GT1 Japanese patients treated with LDV/SOF for 12 weeks.

Risk of hip fracture following stroke, a meta-analysis of 13 cohort studies

This study systematically reviews prospective and retrospective cohort studies evaluating the risk of hip fracture following stroke. Stroke survivors are at high risk of hip fracture and had a 1.5-fold increased risk compared to stroke-free men and women of the same age. Hip fracture often occurs in ageing and female stroke patients. We performed a meta-analysis to summarize evidence from prospective and retrospective cohort studies about the risk of hip fracture following stroke. We identified English and non-English publications in MEDLINE and EMBASE using stroke and fracture as keywords to 31 December 2015. The data of the incidence of hip fracture were extracted to calculate raw incident rate in stroke survivors as well as risk of hip fractures in strokes comparing populations using a random-effects model. Subgroup analyses were performed to identify the potential influence of some factors. Six prospective and seven retrospective cohort studies were included, involving 512,214 stroke patients with 22,559 hip fractures. The pooled prevalence of hip fractures was 4.87 % (95 % CI, 4.05 to 5.68 %) in stoke patients. We conducted subgroup analysis according to sex, age, duration of follow-up, study design, and region, which showed that female (vs. male) stroke patients older than 70 years (vs. those less than 70 years) and duration of follow-up more than 2 years (vs. those less than 2 years) have higher proportions of hip fractures. Four studies showed that stroke patients had a significantly higher risk of hip fracture compared with the general population, while the other study had a non-significant higher risk. The overall prevalence of hip fracture was 3.28 % (3431 of 104,646) in stroke patients and 2.83 % (36,493 of 1,287,726) in general population, respectively, and the unadjusted combined relative risk of hip fracture was 1.54 (95 % CI, 1.06-2.25). Hip fractures often occur in ageing and female stroke patients.

Antiviral response and resistance analysis of treatment-naïve HCV-infected patients receiving single and multiple doses of GS-9190

GS-9190 is a NS5B non-nucleoside analogue with demonstrated effectiveness in a Phase 1 monotherapy study and in combination with other DAAs for treatment of chronic HCV infection. Here, the resistance profile of GS-9190 monotherapy in a Phase 1b study was investigated. Resistance analysis was performed by population sequencing and allele-specific PCR (AS-PCR) for Y448H with an assay cut-off of 0.5%. Phenotypic susceptibility analyses were performed on patient isolates as well as site-directed mutagenesis of mutations selected during monotherapy. No resistance-associated variants were observed in patients before or after receiving single doses of GS-9190 by population sequencing. In contrast, in patients who received GS-9190 for 8 days, mutations Y448H and Y452H in NS5B were observed by population sequencing in 21/36 (58%) and 2/36 (5.6%) patients, respectively, at Day 8 or Day 14. Among the remaining 15 patients who had no detectable Y448H at Day 8 or Day 14 by population sequencing, low frequencies of Y448H ranging from 1.3 to 9.7% were detected in 14 of 15 patients by AS-PCR. By AS-PCR, Y448H remained detectable at reduced frequency in the majority of patients analysed through 4-6 months of follow-up. Chimeric HCV replicons constructed with the NS5B sequence from patients with Y448H and Y448H + Y452H/Y demonstrated 27-fold and 78.5-fold reduced susceptibility to GS-9190. In conclusion, Y448H was rapidly selected in the majority of patients receiving multiple doses of GS-9190 as monotherapy, despite undetectable levels in pretreatment samples. Y448H confers reduced susceptibility to GS-9190 and other NNIs and persisted in most patients for months post-treatment.

A phase 3b study of sofosbuvir plus ribavirin in treatment-naive and treatment-experienced Korean patients chronically infected with genotype 2 hepatitis C virus

In Korea, patients with chronic hepatitis C virus (HCV) infection are typically treated with pegylated interferon-alpha plus ribavirin, but interferons are contraindicated in many patients and are often poorly tolerated, particularly by the elderly and those with advanced liver disease. No interferon-free treatment regimens are approved in Korea. Sofosbuvir is an oral nucleotide analog inhibitor of the HCV nonstructural 5B RNA polymerase. It is approved in the USA, European Union and Japan for treating a number of HCV genotypes, including genotype 2. Genotype 2 has a seroprevalence of 38-46% in Korea. This single-arm, phase 3b study (NCT02021643) examined the efficacy and safety of sofosbuvir plus ribavirin (12-week duration) in chronic genotype 2 HCV-infected treatment-naive and treatment-experienced Korean patients with and without cirrhosis. The proportion of patients with sustained virologic response 12 weeks after treatment discontinuation (SVR12) was 97% (125/129), with 96% (101/105) of treatment-naive and 100% (24/24) of treatment-experienced patients achieving SVR12. Two patients experienced virologic failure (n = 1, on-treatment failure; n = 1, relapse). No patient discontinued study treatment due to an adverse event (AE). The most common treatment-emergent AEs were headache (18%, 23/129) and pruritus (15%, 19/129). Few patients had grade 3 AEs (5%, 6/129) or grade 3 laboratory abnormalities (12%, 15/129). No grade 4 AE was reported. These data suggest that 12 weeks of treatment with the all-oral, interferon-free regimen of sofosbuvir plus ribavirin is effective and well tolerated in Korean patients with chronic genotype 2 HCV infection.

Sofosbuvir plus ribavirin for the treatment of patients with chronic genotype 1 or 6 hepatitis C virus infection in Hong Kong

BACKGROUND

In Hong Kong, most patients with hepatitis C virus (HCV) have either genotype 6a or 1b infection.

AIM

To evaluate the efficacy and safety of sofosbuvir with ribavirin in treatment-naïve patients in Hong Kong with HCV genotype 1 or 6.

METHODS

In an open-label study, patients were randomised to sofosbuvir 400 mg once daily plus ribavirin 1000-1200 divided twice daily for 12 (n = 10), 16 (n = 11) or 24 (n = 10) weeks. The primary endpoint was the percentage of patients with HCV RNA < LLOQ (lower limit of quantification, 25 IU/mL) 12 weeks after cessation of therapy (SVR12).

RESULTS

All 31 patients (20 HCV genotype 1 and 11 genotype 6) had HCV RNA < LLOQ by Week 4 of treatment and at their last on-treatment visit. SVR12 rates were high in all treatment groups: 100% (10/10) for 12 weeks, 100% (11/11) for 16 weeks and 90% (9/10) for 24 weeks of therapy. The only patient who did not reach SVR12 had genotype 1 HCV and relapsed at post-treatment Week 4. Sofosbuvir with ribavirin was generally well tolerated. The most common adverse events were malaise (13%) and upper respiratory tract infection (13%), followed by anaemia (10%). No patients experienced serious adverse events. One patient discontinued treatment at Week 16 because of an adverse event. The event, upper respiratory tract infection, was not considered treatment related by the investigator. This subject achieved SVR12.

CONCLUSIONS

The all-oral regimen sofosbuvir plus ribavirin is effective in treatment-naïve patients in Hong Kong with genotype 1 or 6 HCV.

TRIAL REGISTRATION NUMBER

NCT02021643.

A phase 1, randomized, dose-ranging study of GS-5816, a once-daily NS5A inhibitor, in patients with genotype 1-4 hepatitis C virus

GS-5816 is an inhibitor of the hepatitis C virus (HCV) NS5A protein that has demonstrated pan-genotypic activity and a high barrier to resistance in HCV replicon assays. The aim of this study was to evaluate the safety, antiviral activity and pharmacokinetics of once-daily doses of GS-5816 in patients with genotype 1-4 HCV infection. Patients with genotype 1-4 HCV infection were randomized to 3 days of GS-5816 at doses ranging from 5 to 150 mg or placebo. Adverse events were recorded, and plasma samples obtained for analysis of pharmacokinetics, HCV RNA and NS5A sequencing studies. GS-5816 5-150 mg for 3 days was well tolerated and resulted in rapid declines in HCV RNA that were sustained over the dosing period. In patients treated with the 150 mg dose of GS-5816, the mean maximal HCV RNA declines were 4.0, 4.0, 4.4, 3.3 and 3.5 log10 IU/mL in patients with genotype 1a, 1b, 2, 3 and 4 HCV infection, respectively. Pretreatment NS5A resistance-associated polymorphisms were detected in 31% (22/70) of patients. Genotype 1 and 3 HCV-infected patients without pretreatment NS5A resistance-associated polymorphisms had greater declines in HCV RNA than patients with resistance-associated polymorphisms. Plasma pharmacokinetics were supportive of once-daily dosing. GS-5816 demonstrated pangenotypic antiviral activity in patients with genotype 1-4 HCV infection. It will be further evaluated in combination with other pangenotypic direct-acting antivirals to achieve the goal of developing a well-tolerated, highly effective treatment for all HCV genotypes.

Evolution of the HCV viral population from a patient with S282T detected at relapse after sofosbuvir monotherapy

Clinical phase II/III studies of the nucleotide analogue HCV NS5B inhibitor sofosbuvir (SOF) have demonstrated high efficacy in HCV-infected patients in combination therapy. To date, resistance to SOF (S282T in NS5B) has rarely been detected in patients. In this study, we investigated the evolution of S282T viral variants detected in one HCV genotype 2b-infected patient who relapsed following 12 weeks of SOF monotherapy. Deep sequencing of the NS5B gene was performed on longitudinal plasma samples at baseline, days 2 and 3 on SOF, and longitudinal samples post-SOF treatment through week 48. Intrapatient HCV evolution was analysed by maximum-likelihood phylogenetic analysis. Deep sequencing analysis revealed a low level pre-existence of S282T at 0.05% of viral sequences (4/7755 reads) at baseline and 0.03% (6/23 415 reads) at day 2 on SOF. Viral relapse was detected at week 4 post-treatment where 99.8% of the viral population harboured S282T. Follow-up analysis determined that S282T levels diminished post-treatment reaching undetectable levels 24-48 weeks post-SOF. Phylogenetic analysis together with the persistence of unique post-treatment mutations in all post-SOF samples suggested that growth of wild type resulted from reversion of the S282T mutant to a wild type and not outgrowth of the baseline wild-type population. Our data suggest that a very low level of pre-existing S282T at baseline in this patient was enriched and transiently detected following SOF monotherapy. Despite relapse with drug resistance to SOF, this patient was successfully retreated with SOF plus ribavirin for 12 weeks and is now cured from HCV infection.

Improving production of volatile fatty acids from food waste fermentation by hydrothermal pretreatment

Food waste (FW) was pretreated by a hydrothermal method and then fermented for volatile fatty acid (VFAs) production. The soluble substance in FW increased after hydrothermal pretreatment (⩽200 °C). Higher hydrothermal temperature would lead to mineralization of the organic compounds. The optimal temperature for organic dissolution was 180 °C, at which FW dissolved 42.5% more soluble chemical oxygen demand than the control. VFA production from pretreated FW fermentation was significantly enhanced compared with the control. The optimal hydrothermal temperature was 160 °C with a VFA yield of 0.908 g/g VSremoval. Butyrate and acetate were the prevalent VFAs followed by propionate and valerate. FW fermentation was inhibited after 200 °C pretreatment. The VFAs were extracted from the fermentation broth by liquid-liquid extraction. The VFA recovery was 50-70%. Thus, 0.294-0.411 g VFAs could be obtained per gram of hydrothermally pretreated FW (in dry weight) by this method.

All-oral therapy with nucleotide inhibitors sofosbuvir and GS-0938 for 14 days in treatment-naive genotype 1 hepatitis C (nuclear)

Sofosbuvir and GS-0938 are distinct nucleotide analogues with activity against hepatitis C virus (HCV) in vitro. We evaluated the antiviral activity and safety of sofosbuvir and GS-0938 alone and in combination in HCV genotype 1 patients. In this double-blind study, 40 treatment-naïve patients were randomly assigned to 4 treatment cohorts: (i) GS-0938 for 14 days, (ii) GS-0938 for 7 days followed by GS-0938 plus sofosbuvir for 7 days, (iii) sofosbuvir for 7 days followed by GS-0938 plus sofosbuvir for 7 days and (iv) GS-0938 plus sofosbuvir for 14 days. In each arm, 8 patients received active drug and 2 placebo. After 7 days of dosing, patients in all 4 dose groups experienced substantial reductions in HCV RNA, with median declines (Q1, Q3) of -4.50 (-4.66, -4.24) in Cohort 1, -4.55 (-4.97, -4.13) in Cohort 2, -4.65 (-4.78, -4.17) in Cohort 3 and -4.43 (-4.81, -4.13) in Cohort 4; patients receiving placebo had essentially no change in HCV RNA (+0.07 log(10) IU/mL). Seven days after the end of treatment, the proportions of patients with HCV RNA <15 IU/mL were 4 (50%), 8 (100%), 7 (88%) and 5 (63%) for Cohorts 1-4, respectively, vs 0 for placebo. No viral breakthrough or resistance mutations were observed. No serious adverse events or Grade 3 or 4 adverse events were reported. Sofosbuvir and GS-0938-alone and in combination--were well tolerated and led to substantial reductions in viral load. Sofosbuvir is undergoing further investigation as a possible backbone of an all-oral regimen for chronic HCV.

Natural variation in drug susceptibility to HCV polymerase inhibitors in treatment-naïve HCV patient isolates

Summary.  To assess the natural variation in drug susceptibility among treatment-naïve hepatitis C virus (HCV) patient isolates, the susceptibilities of chimeric replicons carrying the HCV NS5B polymerase from up to 51 patient isolates against a panel of diverse HCV nonnucleoside polymerase inhibitors were evaluated using a replicon-based transient replication assay. Some patient to patient variation in susceptibility to the panel of three HCV nonnucleoside polymerase inhibitors was observed. Linear regression and correlation analyses revealed no correlations among the susceptibilities to the polymerase inhibitors tested. Our results suggest that variable antiviral responses to HCV nonnucleoside polymerase inhibitors may be observed because of the natural variation in baseline susceptibility. In addition, the lack of correlation among the susceptibilities to three classes of HCV polymerase inhibitors evaluated here supports their possible combined use in a combination therapy strategy.

Estimation of inhibitory quotient using a comparative equilibrium dialysis assay for prediction of viral response to hepatitis C virus inhibitors

The relationship of inhibitory quotient (IQ) with the virologic response to specific inhibitors of human hepatitis C virus (HCV) and the best method to correct for serum protein binding in calculating IQ have not been addressed. A common method is to determine a fold shift by comparing the EC(50) values determined in cell culture in the absence and presence of human serum (fold shift in EC(50) ), but this method has a number of disadvantages. In the present study, the fold shifts in drug concentrations between 100% human plasma (HP) and cell culture medium (CCM) were directly measured using a modified comparative equilibrium dialysis (CED) assay for three HCV protease inhibitors (PIs) and for a novel HCV inhibitor GS-9132. The fold shift values in drug concentration between the HP and CCM (CED ratio) were ∼1 for SCH-503034, VX-950 and GS-9132 and 13 for BILN-2061. These values were ∼3-10-fold lower than the fold shift values calculated from the EC(50) assay for all inhibitors except BILN-2061. Using the CED values, a consistent pharmacokinetic and pharmacodynamic relationship was observed for the four HCV inhibitors analysed. Specifically, an approximate 1 log(10) reduction in HCV RNA was achieved with an IQ close to 1, while 2-3 and greater log(10) reductions in HCV RNA were achieved with IQ values of 3-5 and greater, respectively. Thus, use of CED to define IQ provides a predictive and quantitative approach for the assessment of the in vivo potency of HCV PIs and GS-9132. This method provides a framework for the evaluation of other classes of drugs that are bound by serum proteins but require the presence of serum for in vitro evaluation.

An experimental study on the effect of spacer on concentration polarization in a long channel reverse osmosis membrane cell

This study was to experimentally investigate the performance and organic fouling behaviour in a 1-m long RO membrane channel with or without spacer for desalting. It was found that local permeate flux distributed heterogeneously along the long membrane channel without a spacer inserted due to exponential growth of concentration polarization, which also resulted in decreasing salt rejection and increasing organic fouling along the membrane channel in the downstream direction. This heterogeneity could be lessened by inserting a spacer into the channel, which mitigated concentration polarization due to the enhanced turbulence caused by a spacer, especially at the downstream portion of the channel. However, in the upstream of the channel, inserting a spacer exerted an additional vertical resistance which might counteract the effect of concentration polarization mitigation by a spacer and caused a lower permeate flux. This suggests that it is necessary to consider the integral effect of spacer for designing an RO membrane module and an overall RO system in order to prevent extra resistance, reduce concentration polarization and membrane fouling.