Single Systemic Administration of a Gene Therapy Leading to Disease Treatment in Metachromatic Leukodystrophy Arsa Knock-Out Mice.

Metachromatic leukodystrophy (MLD) is a rare, inherited, demyelinating lysosomal storage disorder caused by mutations in the arylsulfatase-A gene (ARSA). In patients, levels of functional ARSA enzyme are diminished and lead to deleterious accumulation of sulfatides. Herein, we demonstrate that intravenous administration of HSC15/ARSA restored the endogenous murine biodistribution of the corresponding enzyme, and overexpression of ARSA corrected disease biomarkers and ameliorated motor deficits in Arsa KO mice of either sex. In treated Arsa KO mice, when compared with intravenously administered AAV9/ARSA, significant increases in brain ARSA activity, transcript levels, and vector genomes were observed with HSC15/ARSA Durability of transgene expression was established in neonate and adult mice out to 12 and 52 weeks, respectively. Levels and correlation between changes in biomarkers and ARSA activity required to achieve functional motor benefit was also defined. Finally, we demonstrated blood-nerve, blood-spinal and blood-brain barrier crossing as well as the presence of circulating ARSA enzyme activity in the serum of healthy nonhuman primates of either sex. Together, these findings support the use of intravenous delivery of HSC15/ARSA-mediated gene therapy for the treatment of MLD.SIGNIFICANCE STATEMENT Herein, we describe the method of gene therapy adeno-associated virus (AAV) capsid and route of administration selection leading to an efficacious gene therapy in a mouse model of metachromatic leukodystrophy. We demonstrate the therapeutic outcome of a new naturally derived clade F AAV capsid (AAVHSC15) in a disease model and the importance of triangulating multiple end points to increase the translation into higher species via ARSA enzyme activity and biodistribution profile (with a focus on the CNS) with that of a key clinically relevant biomarker.

Workshop Proceedings: Streamlined Development of Safety Assessment Programs Supporting Orphan/Rare Diseases-Are We There Yet?

A workshop entitled "Streamlined Development of Safety Assessment Programs Supporting Orphan/Rare Diseases-Are We There Yet?" was held at the 36th Annual Meeting of the American College of Toxicology in Summerlin, Nevada. The workshop was sponsored by Shire and Ultragenyx and was designed to present the nonclinical considerations for the development of various products for rare diseases. A panel of experts from industry and government highlighted the nonclinical considerations in developing toxicology programs supporting rare disease therapeutics, challenges in preclinical safety assessment, reviewed the current guidance, and presented the progress that has been made to date. The main learning from the workshop was that nonclinical testing of therapeutics targeting rare disease warrants special considerations, and early collaboration between sponsors and health authorities may help optimize the scope and timing of the supportive studies. Specific examples for nonclinical development programs for enzyme replacement therapy (ERT) were presented. Although the symposium focused on ERTs, the concepts are broadly applicable.

Primary cervical cancer screening with human papillomavirus: end of study results from the ATHENA study using HPV as the first-line screening test.

OBJECTIVES: ATHENA evaluated the cobas HPV Test as the primary screen for cervical cancer in women ≥25years. This reports the 3-year end-of-study results comparing the performance of HPV primary screening to different screening and triage combinations. METHODS: 42,209 women ≥25years were enrolled and had cytology and hrHPV testing. Women with abnormal cytology (≥atypical squamous cells of undetermined significance) and those HPV positive were referred to colposcopy. Women not reaching the study endpoint of CIN2+ entered the 3-year follow-up phase. RESULTS: 3-year CIR of CIN3+ in cytology-negative women was 0.8% (95% CI; 0.5-1.1%), 0.3% (95% CI 0.1-0.7%) in HPV-negative women, and 0.3% (95% CI; 0.1-0.6%) in cytology and HPV negative women. The sensitivity for CIN3+ of cytology was 47.8% (95% CI; 41.6-54.1%) compared to 61.7% (95% CI; 56.0-67.5%) for the hybrid strategy (cytology if 25-29years and cotesting with cytology and HPV if ≥30years) and 76.1% (95% CI; 70.3-81.8%) for HPV primary. The specificity for CIN3+ was 97.1% (95% CI; 96.9-97.2%), 94.6% (95% CI; 94.4-94.8%), and 93.5% (95% CI; 93.3-93.8%) for cytology, hybrid strategy, and HPV primary, respectively. Although HPV primary detects significantly more cases of CIN3+ in women ≥25years than either cytology or hybrid strategy, it requires significantly more colposcopies. However, the number of colposcopies required to detect a single CIN3+ is the same as for the hybrid strategy. CONCLUSIONS: HPV primary screening in women ≥25years is as effective as a hybrid screening strategy that uses cytology if 25-29years and cotesting if ≥30years. However, HPV primary screening requires less screening tests.

Proof of concept for a banding scheme to support risk assessments related to multi-product biologics manufacturing.

A banding scheme theory has been proposed to assess the potency/toxicity of biologics and assist with decisions regarding the introduction of new biologic products into existing manufacturing facilities. The current work was conducted to provide a practical example of how this scheme could be applied. Information was identified for representatives from the following four proposed bands: Band A (lethal toxins); Band B (toxins and apoptosis signals); Band C (cytokines and growth factors); and Band D (antibodies, antibody fragments, scaffold molecules, and insulins). The potency/toxicity of the representative substances was confirmed as follows: Band A, low nanogram quantities exert lethal effects; Band B, repeated administration of microgram quantities is tolerated in humans; Band C, endogenous substances and recombinant versions administered to patients in low (interferons), intermediate (growth factors), and high (interleukins) microgram doses, often on a chronic basis; and Band D, endogenous substances present or produced in the body in milligram quantities per day (insulin, collagen) or protein therapeutics administered in milligram quantities per dose (mAbs). This work confirms that substances in Bands A, B, C, and D represent very high, high, medium, and low concern with regard to risk of cross-contamination in manufacturing facilities, thus supporting the proposed banding scheme.

The ATHENA human papillomavirus study: design, methods, and baseline results.

OBJECTIVE: The objective of the study was to describe baseline data from Addressing the Need for Advanced HPV Diagnostics, a prospective, multicenter US cervical cancer screening trial. STUDY DESIGN: A total of 47,208 women aged 21 years or older undergoing routine screening were enrolled; liquid-based cytology and human papillomavirus (HPV) testing were performed. Women with abnormal cytology underwent colposcopy, as did high-risk HPV (hrHPV)-positive women and a random subset of women negative by both tests aged 25 years or older. Verification bias adjustment was applied; 95% confidence intervals were computed by the bootstrap method. RESULTS: The prevalence of cytologic abnormalities was 7.1%. hrHPV, HPV 16, and HPV 18 were detected using the cobas HPV Test in 12.6%, 2.8%, and 1.0% of women, respectively. Both cytologic abnormalities and hrHPV positivity declined with increasing age. The adjusted prevalence of cervical intraepithelial neoplasia grade 2 (CIN2) or greater in women aged 25-34 years was 2.3%, decreasing to 1.5% among older women. CONCLUSION: The Addressing the Need for Advanced HPV Diagnostics study provides important estimates of the prevalence of cytologic abnormalities, hrHPV positivity, and CIN2 or greater in a US screening population.

Performance of carcinogenic human papillomavirus (HPV) testing and HPV16 or HPV18 genotyping for cervical cancer screening of women aged 25 years and older: a subanalysis of the ATHENA study.

BACKGROUND: The ATHENA study was designed to assess the performance of carcinogenic human papillomavirus (HPV) testing and HPV16 or HPV18 genotyping compared with liquid-based cytology for cervical cancer screening in a large US population aged 21 years and older. We did a subanalysis of this population to compare the screening performance of the cobas HPV test versus liquid-based cytology in women aged 25 years and older, and assess management strategies for HPV-positive women. METHODS: Women aged 25 years or older who were attending routine cervical screening were enrolled from 61 clinical centres in 23 US states. Cervical specimens were obtained for liquid-based cytology and HPV DNA testing with two first-generation assays (Amplicor HPV test and Linear Array HPV genotyping test) and the second-generation cobas HPV test (with individual HPV16 and HPV18 detection). Colposcopy and diagnostic biopsies were done on women with atypical squamous cells of undetermined significance (ASC-US) or worse cytology, those who tested positive with either first-generation HPV test, and a random sample of women who tested negative for HPV and cytology. All women not selected for colposcopy received their results and exited the study. Participants and colposcopists were masked to cytology and HPV test results until the colposcopy visit was completed. The primary endpoint for this substudy was histologically confirmed cervical intraepithelial neoplasia grade 3 (CIN3) or worse. This study is registered with ClinicalTrials.gov, number NCT00709891; the study is in the follow-up phase, which is due to be completed in December, 2012. FINDINGS: From May 27, 2008, to Aug 27, 2009, 47,208 women were enrolled, of whom 41,955 met our eligibility criteria. Valid cobas HPV and liquid-based cytology test results were available for 40,901 women (97%), who were included in this analysis. Of these, 4275 women (10%) tested cobas HPV positive and 2617 (6%) had abnormal cytology. 431 women were diagnosed with CIN2 or worse and 274 with CIN3 or worse. In women who had colposcopy, the cobas HPV test was more sensitive than liquid-based cytology for detection of CIN3 or worse (252/274 [92·0%, 95% CI 88·1-94·6] vs 146/274 [53·3%, 95% CI 47·4-59·1]; difference 38·7%, 95% CI 31·9-45·5; p<0·0001). Addition of liquid-based cytology to HPV testing increased sensitivity for CIN3 or worse to 96·7% (265/274, 95% CI 93·9-98·3), but increased the number of screen positives by 35·2% (5783/40,901 vs 4275/40,901) compared with HPV testing alone. As a triage test to identify CIN3 or worse in HPV-positive women, detection of HPV16, HPV18, or both alone was equivalent to detection of ASC-US or worse alone in terms of sensitivity (150/252 [59·5%] vs 133/252 [52·8%]; p=0·11) and positive predictive value (PPV) (150/966 [15·5%] vs 133/940 [14·1%]; p=0·20). Among HPV-positive women, detection of HPV16, HPV18, or both or low-grade squamous intraepithelial lesion or worse cytology had better sensitivity (182/252 [72·2%]; p<0·0001) and similar PPV (182/1314 [13·9%]; p=0·70) for detection of CIN3 or worse than ASC-US or worse cytology alone. Furthermore, detection of HPV16, HPV18, or both or high-grade squamous intraepithelial lesion or worse cytology had higher sensitivity (165/252 [65·5%]; p=0·0011) and PPV (165/1013 [16·3%]; p=0·031) for detection of CIN3 or worse than ASC-US or worse cytology alone. INTERPRETATION: HPV testing with separate HPV16 and HPV18 detection could provide an alternative, more sensitive, and efficient strategy for cervical cancer screening than do methods based solely on cytology. FUNDING: Roche Molecular Systems.

Safety evaluation of chronic intrathecal administration of idursulfase-IT in cynomolgus monkeys.

Recombinant human idursulfase, an intravenous enzyme replacement therapy indicated for treatment of somatic symptoms of mucopolysaccharidosis II (Hunter syndrome), is anticipated to have minimal benefit for the cognitive impairment associated with the severe phenotype. Because intrathecal (IT) administration of enzyme replacement therapy for other lysosomal enzyme disorders has shown efficacy in animal models, an IT formulation of idursulfase (idursulfase-IT) and a drug-delivery device (subcutaneous port connected to a lumbar IT catheter) were developed for treating central nervous system (CNS) involvement. In this chronic safety study, cynomolgus monkeys were dosed weekly with IV idursulfase (0.5 mg/kg) and every four weeks with idursulfase-IT (3, 30, and 100 mg) for six months, with device and vehicle controls treated similarly (n = 6, all groups). Necropsies were performed twenty-four hours post-final IT dose or after a recovery period (four weeks post-final dose in vehicle-control, 3 mg, and 100 mg IT groups: n = 6). No clinical signs or gross central nervous system lesions were observed. Compared to controls, more pronounced cellular infiltrates in brain and spinal cord meninges were noted, which largely resolved after the recovery period. Central nervous sytem levels of idursulfase-IT were dose dependent, as determined by enzyme activity and immunohistochemistry. The no-observed-adverse-effect level of idursulfase-IT was 100 mg.

Testing strategy to identify cases of acute hepatitis C virus (HCV) infection and to project HCV incidence rates.

Surveillance for hepatitis C virus (HCV) is limited by the challenge of differentiating between acute and chronic infections. In this study, we evaluate a cross-sectional testing strategy that identifies individuals with acute HCV infection and we estimate HCV incidence. Anti-HCV-negative persons from four populations with various risks, i.e., blood donors, Veterans Administration (VA) patients, young injection drug users (IDU), and older IDU, were screened for HCV RNA by minipool or individual sample nucleic acid testing (NAT). The number of detected viremic seronegative infections was combined with the duration of the preseroconversion NAT-positive window period (derived from analysis of frequent serial samples from plasma donors followed from NAT detection to seroconversion) to estimate annual HCV incidence rates. Projected incidence rates were compared to observed incidence rates. Projected HCV incidence rates per 100 person-years were 0.0042 (95% confidence interval [95% CI], 0.0025 to 0.007) for blood donors, 0.86 (95% CI, 0.02 to 0.71) for VA patients, 39.8 (95% CI, 25.9 to 53.7) for young IDU, and 53.7 (95% CI, 23.4 to 108.8) for older IDU. Projected rates were most similar to observed incidence rates for young IDU (33.4; 95% CI, 28.0 to 39.9). This study demonstrates the value of applying a cross-sectional screening strategy to detect acute HCV infections and to estimate HCV incidence.

Post-transplant recurrent hepatitis C: immunohistochemical detection of hepatitis C virus core antigen and possible pathogenic implications.

INTRODUCTION: The mechanisms by which severe cholestatic hepatitis develops after liver transplantation are not fully understood. Reports on immunohistochemical distribution of hepatitis C virus (HCV) antigens are still scarce, but recently, HCV immunostaining was suggested for early diagnosis of cholestatic forms of recurrent hepatitis C in liver grafts. After purification, Rb246 pab anticore (aa1-68) yielded specific, granular cytoplasmic staining in hepatocytes. Signal amplification through the Envision-Alkaline Phosphatase System avoided endogenous biotin and peroxidase. AIMS/METHODS: Rb246 was applied to liver samples of explants of 12 transplant recipients, six with the most severe form of post-transplantation recurrence, severe cholestatic hepatitis (group 1) and six with mild recurrence (group 2). We also assessed immuno-reactivity at two time-points post-transplantation (median 4 and 22 months) in both groups. HCV-core Ag was semiquantified from 0 to 3+ in each time point. Serum HCV-RNA was also measured on the different time points by branched DNA. RESULTS: In the early post-transplant time point, one patient had a mild staining (1+), two patients had a moderate staining (2+) and the other three had no staining in group 1, compared with five patients with no staining (0) and one patient with mild staining (1+) in group 2. Late post-transplant liver samples were available in nine patients, and two out of four samples in group 1 showed a mild staining, compared with no staining patients in five patients in group 2. Strikingly, on the explant samples, HCV immunostaining was strongly positive in group 1, and mildly positive in group 2. Two out of five samples showed 3+ staining, and three samples showed 2+ staining in group 1; two out of five samples showed no staining, two samples showed 1+ staining and one sample showed 2+ staining in group 2. Serum HCV-RNA was significantly higher in group 1, on both time-points post-transplantation. HCV-core Ag was not directly associated with serum HCV-RNA on the different time points. CONCLUSION: These preliminary results suggest that strong HCV immunostaining in the explant is predictive of more severe disease recurrence.

A prospective study to examine persistent HCV reinfection in injection drug users who have previously cleared the virus.

BACKGROUND: Many HCV-infected persons with recent or ongoing injection drug use (IDU) do not receive HCV treatment due to the perceived risk of HCV reinfection. There are few prospective studies investigating HCV reinfection among IDUs. METHODS: Two hundred and twenty-four persons with past or ongoing IDU were followed from 1997 to 2007. Baseline and every 6-month follow-up data were collected including demographics, IDU, and sexual behaviors. Serum was tested for the presence of HCV antibody and serially for HCV RNA. Resolvers were defined as HCV antibody and RIBA positive and RNA negative at two consecutive time points or as becoming HCV RNA negative after HCV antiviral treatment. Reinfection was defined by the presence of HCV RNA at > or =2 visits. RESULTS: One hundred and eighty-six persons had chronic HCV and 38 had resolved HCV. The resolvers were followed for a total of 214 person-years. Forty-two percent of resolvers reported ongoing IDU, representing 58 person-years of IDU. Only one reinfection occurred in the resolvers, for a reinfection rate of 0.47 cases/100 person-years of follow-up. The single reinfection, which occurred in a person who continued to inject drugs, represents a reinfection rate of 1.75 cases/100 person-years of IDU. CONCLUSION: These data suggest that despite ongoing IDU, persistent HCV reinfection is lower than previously published. This can be attributed to a more clinically relevant definition of reinfection. This information will better help clinicians make informed decisions regarding HCV treatment options for patients who may continue to inject illicit drugs.

Can we predict the degree of fibrosis in chronic hepatitis C patients using routine blood tests in our daily practice?

GOALS: To determine the validity of fibrosis indexes based on simple laboratory tests in daily practice. BACKGROUND: Fibrosis indexes were developed in referral centers using high-quality data. METHODS: We compared the performance characteristics of several such indexes with liver biopsies in a cohort of 490 diverse veterans with chronic hepatitis C from 24 centers. All laboratory tests including interpretation of the liver biopsy were done locally. The following indexes were calculated and correlated with a 5-point fibrosis stage (F0-F4) on liver biopsies: platelet counts (<100 or <150x10(9)/L), aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio (AAR), Pohl score, AST-to-platelet ratio index (APRI) and "Lok's model." RESULTS: Our cohort was predominantly male with 24% blacks, and fibrosis stages of 0, 1, 2, 3, and 4 in 11%, 24%, 28%, 24%, and 13%, respectively. All indexes performed better in predicting advanced (F3-4) than significant (F2-4) fibrosis. When patients with F3-4 were compared to those with F0-2, the area under the receiver operating characteristics curve were 0.534 and 0.641 for platelet count <100 and <150x10(9)/L, respectively, 0.524 for AAR, 0.534 for Pohl score, 0.693 for Lok's model, and 0.765 for APRI. The sensitivity, specificity, and predictive values of APRI and Lok's model were only slightly lower than those reported by the authors using the recommended cutoffs in clinical trial settings. Alcohol use within 12 months, normalization of AST, ALT, and race (blacks/non-blacks) had minimal impact on the performance. CONCLUSIONS: AAR, Pohl, and platelet counts <100x10(9)/L have limited ability to predict significant/advanced fibrosis with area under the receiver operating characteristics curve similar to 0.5. However, platelet counts <150x10(9)/L, Lok's model and APRI performed well for advanced fibrosis in our daily practice setting.

Liver disease in injection drug users with hepatitis C, with and without HIV coinfection.

Liver disease is a major health problem for individuals with a history of injection drug use. This is mainly from the hepatitis C virus (HCV), with or without co-infection with HIV. HCV-associated liver disease takes decades to develop into cirrhosis, from which it can adversely affect health. HIV coinfection is among the factors that are often associated with liver disease progression, and efforts to understand liver disease progression in HIV-HCV coinfected patients remain important. Maintaining high CD4 counts and avoiding alcohol intake are associated with slower liver disease progression. Pegylated interferon and ribavirin combination therapy has the potential to clear HCV, which provides the strongest health benefit to patients affected by the virus, although this can be difficult to accomplish for many reasons. Steatosis, fat within the liver, may also have important pathological implications for liver disease related to HCV. Limiting liver disease progression in IDUs with hepatitis C may well be best accomplished through promoting their full utilization of health care.

Impact of ribavirin dose reductions in hepatitis C virus genotype 1 patients completing peginterferon alfa-2a/ribavirin treatment.

BACKGROUND & AIMS: To maximize sustained virologic response (SVR) in patients with chronic hepatitis C virus (HCV) infection, treatment with pegylated interferon and ribavirin has been genotype-specific (1 vs non-1). We evaluated the effects of ribavirin and peginterferon alfa-2a dose reductions on SVR in patients infected with HCV genotype 1. METHODS: Data were pooled from 569 patients enrolled in 2 phase III trials of 48 weeks of treatment with peginterferon alfa-2a and ribavirin. All patients were evaluated for the effect of cumulative drug exposure on 4- and 12-week responses, and the 427 patients who completed treatment were evaluated for effect of drug exposure on SVR. RESULTS: Of patients who completed treatment, more had reductions (< or =97% cumulative dose) of ribavirin than of peginterferon alfa-2a (43% vs 27%). Neither early virologic response nor SVR was affected adversely by ribavirin reductions when the cumulative ribavirin exposure was greater than 60%. The SVR was reduced significantly (P = .0006) in patients with less than the 60% cumulative ribavirin dose and was associated with prolonged periods of dose reduction, temporary interruptions, or premature cessation of ribavirin. Ribavirin dose reductions had minimal impact on SVR in patients who achieved rapid virologic response, defined as undetectable HCV RNA levels after 4 weeks, even when they received less than the 60% cumulative ribavirin dose. In contrast, SVR was reduced markedly in patients who had ribavirin dose reductions and did not achieve rapid virologic response. CONCLUSIONS: Minor ribavirin dose reductions to manage adverse events do not appear to affect SVR adversely, unless cumulative exposure is less than 60%. Prospective studies, however, are required to establish the impact of ribavirin dose reduction on SVR.

Trends for genetic variation of Hepatitis C Virus quasispecies in Human Immunodeficiency virus-1 coinfected patients.

Chronic infection by Hepatitis C Virus (HCV) causes liver fibrosis, which is accelerated by unknown mechanisms in patients with HIV-1 coinfection. The evolution of HCV quasispecies in this setting of coinfection is not fully understood. To compare HCV quasispecies between HIV-HCV coinfection and HCV monoinfection, we sequenced 340 HCV clones from the HVR-1 and NS3 regions at two different time points in two groups of treatment-naïve patients with HCV-1a infection: (1) HIV-HCV positive (n=6); and (2) HIV negative-HCV positive (n=3). In HCV/HIV coinfection, we found a trend for reduced HCV genetic complexity and diversity, and a trend towards reduced dN/dS ratios in the HVR-1 region, especially in those patients with CD4<200cells/mm(3), who lost positive selective immune pressure in the HVR-1 region. Differences in immune regulation of HCV quasispecies in HIV coinfected individuals deserve further exploration to clarify the different outcomes of chronic hepatitis C noted between the immunocompromised and the immunocompetent host.

Antiviral therapy and primary and secondary prevention of hepatocellular carcinoma.

Viral hepatitis due to chronic hepatitis B and C virus (HBV/HCV) infects more than 500 000 000 individuals worldwide. These chronic viral diseases are highly linked to the development of hepatocellular carcinoma (HCC), the fifth most common cause of cancer death worldwide. HCC is much more common in Asia and Africa than in the USA and Europe, although HCC is one of the few cancers with a rising incidence in the USA. There are 530 000 cases of HCC worldwide of which 82% are related to viral hepatitis. 316 000 cases of HCC are HBV-associated, 118 000 are HCV-associated. The most effective way to prevent HCC is to prevent viral infection through immunization. Currently there are effective vaccinesagainst hepatitis B and A, but not against HCV, the virus that accounts for most HCC in the USA. The published work supporting the use of antiviral therapy in preventing liver cancer is limited. Data supporting the use of antiviral therapy in preventing recurrence of HCC after initial anticancer approaches is even less available. Nevertheless, the weight of evidence suggests that treatment of HBV/HCV-related fibrosis will reduce the risk of developing HCC.

Safety Evaluation of CNS Administered Biologics-Study Design, Data Interpretation, and Translation to the Clinic.

Many central nervous system (CNS) diseases are inadequately treated by systemically administered therapies due to the blood brain barrier (BBB), which prevents achieving adequate drug concentrations at sites of action. Due to the increasing prevalence of neurodegenerative diseases and the inability of most systemically administered therapies to cross the BBB, direct CNS delivery will likely play an increasing role in treatment. Administration of large molecules, cells, viral vectors, oligonucleotides, and other novel therapies directly to the CNS via the subarachnoid space, ventricular system, or parenchyma overcomes this obstacle. Clinical experience with direct CNS administration of small molecule therapies suggests that this approach may be efficacious for the treatment of neurodegenerative disorders using biological therapies. Risks of administration into the brain tissue or cerebrospinal fluid include local damage from implantation of the delivery system and/or administration of the therapeutic and reactions affecting the CNS. Preclinical safety studies on CNS administered compounds must differentiate between the effects of the test article, the delivery device, and/or the vehicle, and assess exacerbations of reactions due to combinations of effects. Animal models characterized for safety assessment of CNS administered therapeutics have enabled human trials, but interpretation can be challenging. This manuscript outlines the challenges of preclinical intrathecal/intracerebroventricular/intraparenchymal studies, evaluation of results, considerations for special endpoints, and translation of preclinical findings to enable first-in-human trials. Recommendations will be made based on the authors' collective experience with conducting these studies to enable clinical development of CNS-administered biologics.

Adeno-Associated Virus Gene Therapy for Liver Disease.

The field of adeno-associated virus (AAV) gene therapy has progressed rapidly over the past decade, with the advent of novel capsid serotype and organ-specific promoters, and an increasing understanding of the immune response to AAV administration. In particular, liver-directed therapy has made remarkable strides, with a number of clinical trials currently planned and ongoing in hemophilia A and B, as well as other liver disorders. This review focuses on liver-directed AAV gene therapy, including historic context, current challenges, and future developments.

ACAT2 is localized to hepatocytes and is the major cholesterol-esterifying enzyme in human liver.

BACKGROUND: Two acyl-coenzyme A:cholesterol acyltransferase (ACAT) genes, ACAT1 and ACAT2, have been identified that encode 2 proteins responsible for intracellular cholesterol esterification. METHODS AND RESULTS: In this study, immunohistology was used to establish their cellular localization in human liver biopsies. ACAT2 protein expression was confined to hepatocytes, whereas ACAT1 protein was found in Kupffer cells only. Studies with a highly specific ACAT2 inhibitor, pyripyropene A, in microsomal activity assays demonstrated that ACAT2 activity was highly variable among individual human liver samples, whereas ACAT1 activity was more similar in all specimens. ACAT2 provided the major cholesterol-esterifying activity in 3 of 4 human liver samples examined. CONCLUSIONS: The data suggest that in diseases in which dysregulation of cholesterol metabolism occurs, such as hypercholesterolemia and atherosclerosis, ACAT2 should be considered a target for prevention and treatment.

Hepatitis C virus infection among prisoners in the California state correctional system.

BACKGROUND: Incarcerated populations are at high risk for hepatitis C virus (HCV) infection, yet prisoners are not routinely screened or treated for HCV infection. Understanding the risk factors of HCV infection among prisoners could help improve HCV interventions. METHODS: Prevalence and risk of HCV infection among 469 prisoners entering California State correctional facilities were assessed using HCV antibody screening, HCV RNA measurement, and structured interviews. Multivariate logistic regression analysis was used to identify independent correlates of HCV infection. RESULTS: The prevalence of HCV infection was 34.3% overall (95% confidence interval [CI], 30%-38%) and was 65.7% among those with a history of injection drug use (IDU), compared with 10.2% among those with no history of IDU (odds ratio [OR], 17.24; 95% CI, 10.52-28.25). Significant differences in HCV antibody positivity were found in association with age at first detention but not with the nature of the crime. Independent correlates of HCV infection included age, history of IDU, cumulative time of incarceration, biological sex (OR for females subjects compared with males subjects, 0.35; 95% CI, 0.13-0.96), and a history of having sex with a male IDU (OR, 4.42; 95% CI, 1.46-13.37). We identified significant differences in risk factors between male and female subjects--notably, that the risk of HCV infection was significantly elevated among female non-IDUs who reported having sexual partners with a history of IDU. Among non-IDUs, correlates of HCV infection included history of receipt of blood products and cumulative years of incarceration. CONCLUSIONS: HCV infection is pervasive among the California prison population, including prisoners who are non-IDUs and women with high-risk sexual behavior. These results should promote consideration of routine HCV antibody screening and behavioral interventions among incarcerated men and women.

Biological role of glutathione in nitric oxide-induced toxicity in cell culture and animal models.

Glutathione (GSH) plays an important role in cellular defense response in many in vitro and in vivo models. Here we investigated its role in NO()-induced toxicity in cell culture and mouse models. Wild-type (TK6) and p53-null (NH32) human lymphoblastoid cells were treated with NO(.) at a steady-state concentration of 0.6 muM, similar to the level estimated to occur in inflamed tissues. In both cell types, GSH was depleted by this exposure in a dose- and time-dependent manner. Contrary to expectations, prior depletion of GSH by treatment with l-buthionine-SR-sulfoximine did not potentiate NO(.)-induced cell killing or DNA deamination in TK6 cells. In activated RAW264.7 murine macrophages producing NO(.), intracellular GSH content did not change, although gamma-glutamate-cysteine ligase was upregulated. NO(.) overproduction in RcsX lymphoma-bearing SJL mice resulted in significantly elevated GSH levels in various organs. Administration of the NO(.) synthase inhibitor N-methylarginine abolished the increase in GSH in these animals. Collectively, these data indicate a multifaceted and complex involvement of GSH in responses of cells and tissues to toxic levels of NO(.). NO(.) treatment effectively depleted GSH levels in human lymphoblastoid cells, but this alteration was not a critical initiating factor for NO(.)-mediated toxicity. Murine macrophages maintained GSH homeostasis when exposed to endogenously produced NO(.). In RcsX lymphoma-bearing mice, upregulation of de novo synthesis of GSH appeared to be a response to the toxic effects of NO(.).