A longitudinal study of hepatitis C virus testing and infection status notification on behaviour change in people who inject drugs

BACKGROUND

Hepatitis C virus (HCV) testing and counselling have the potential to impact individual behaviour and transmission dynamics at the population level. Evidence of the impact of an HCV-positive status notification on injection risk reduction is limited. The objective of our study was to (1) assess drug and alcohol use and injection risk behaviours following notification; (2) to compare behaviour change in people who inject drugs (PWID) who received a positive test result and those who remained negative; and (3) to assess the effect of age on risk behaviour.

METHODS

Data from the International Collaboration of Incident HIV and HCV Infection in Injecting Cohorts (InC3 Study) were analysed. Participants who were initially HCV seronegative were followed prospectively with periodic HCV blood testing and post-test disclosure and interview-administered questionnaires assessing drug use and injection behaviours. Multivariable generalised estimating equations were used to assess behavioural changes over time.

RESULTS

Notification of an HCV-positive test was independently associated with a small increase in alcohol use relative to notification of a negative test. No significant differences in postnotification injection drug use, receptive sharing of ancillary injecting equipment and syringe borrowing postnotification were observed between diagnosis groups. Younger PWID receiving a positive HCV test notification demonstrated a significant increase in subsequent alcohol use compared with younger HCV negative.

CONCLUSIONS

The proportion of PWID reporting alcohol use increased among those receiving an HCV-positive notification, increased the frequency of alcohol use postnotification, while no reduction in injection drug use behaviours was observed between notification groups. These findings underscore the need to develop novel communication strategies during post-test notification to improve their impact on subsequent alcohol use and risk behaviours.

Abstract 4495: Small molecule approach for targeting tumor-associated macrophages via a functional FRβ

Tumor-associated macrophages (TAMs) are considered an attractive target for oncotherapy because of their important role in tumor microenvironment. While TAMs mostly arise from inflammatory blood monocytes, they become quickly programmed to the pro-tumor phenotype. In response to tumor-derived factors, these M2-biased TAMs are essentially tumor helper cells, as both cancer cells and TAMs promote each another through a paracrine signaling loop involving epidermal growth factor and colony stimulating factor-1. This important cellular interaction is critical at all stages of tumor progression including angiogenesis, invasion, growth and metastasis.

In recent years, TAMs (CD68+, CD163+) have been found to express a functional folate receptor-β (FRβ) that displays high-affinity ligand binding and subsequent ligand-initiated endocytosis. FRβ-expressing TAMs are present in various cancer subtypes, the perivascular region, and the tumor invasive front. The abundance of FRβ+ TAMs has been linked to poor patient survival in pancreatic ductal adenocarcinoma. In the present study, we first characterized the phenotype of FRβ+ TAMs ex-vivo from both syngeneic and xenographic tumor models (breast, lung, melanoma, and pancreatic cancers). Using thioglycollate-elicited macrophages as positive controls, we estimated FRβ levels on TAMs with monoclonal antibodies and functional folate ligands. Using a ligand conjugation approach, we focused on targeting FRβ+ TAMs in tumors arising from cancer cells that do not express functional FR themselves. Preliminary proof-of-concept was established in the highly aggressive FR-negative 4T1 mammary tumor with a folate-targeted DNA alkylating agent. In addition, immunohistochemical analysis showed high FRβ expression in human anaplastic thyroid cancer, a TAM-rich disease with very poor prognosis. Collectively, our data suggest that targeting a TAM-rich cancer via FRβ may be a viable therapeutic approach with potential applications in FR-negative tumors.

Citation Format: Leroy W. Wheeler, Yingjuan Lu, Vicky Cross, Alex Lloyd, Nikki Parker, Longwu Qi, Kevin Wang, Ian Wang, Spencer Hahn, Jeremy Vaughn, Iontcho P. Vlahov, Philip S. Low, Christopher P. Leamon. Small molecule approach for targeting tumor-associated macrophages via a functional FRβ. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4495. doi:10.1158/1538-7445.AM2015-4495

The interaction between peripheral and central fatigue at different muscle temperatures during sustained isometric contractions

Changes in central fatigue have been linked to active and passive changes in core temperature, as well as integration of sensory feedback from thermoreceptors in the skin. However, the effects of muscle temperature (Tm), and thereby metaboreceptor and local afferent nerve temperature, on central fatigue (measured using voluntary activation percentage) during sustained, high muscle fatigue exercise remain unexamined. In this study, we investigated Tm across the range of cold to hot, and its effect on voluntary activation percentage during sustained isometric contractions of the knee extensors. The results suggest that contrary to brief contractions, during a sustained fatiguing contraction Tm significantly (P < 0.001) influences force output (-0.7%/°C increase) and central fatigue (-0.5%/°C increase), showing a negative relationship across the Tm continuum in moderately trained individuals. The negative relationship between voluntary activation percentage and Tm indicates muscle temperature may influence central fatigue during sustained and high muscle fatigue exercise. On the basis of on an integrative analysis between the present data and previous literature, the impact of core and muscle temperature on voluntary muscle activation is estimated to show a ratio of 5.5 to 1, respectively. Accordingly, Tm could assume a secondary or tertiary role in the reduction of voluntary muscle activation when body temperature leaves a thermoneutral range.

A novel subclass of bovine β-defensins links reproduction and immunology

β-defensins are effector molecules of the innate immune system, found in many diverse species. Their presence in invertebrates as well as vertebrates suggests highly conserved functional roles. Most β-defensins are believed to act as antimicrobial agents at epithelial surfaces, although additional functions have also been described, including immune regulatory activity, wound repair and a role in coat-colour determination. High expression of β-defensins have been found in testis and epididymidal epithelium as well as in the seminal fluid of humans, macaque, rat, mouse and cow. Human and macaque β-defensins have recently been shown to affect sperm motility while a mutation in β-defensin 126 is associated with reduced fertility in men. Genetic variation in bovine defensin genes may explain the increased incidence of low fertility in cattle. Here, we present a summary of the known functions of β-defensins as well as their emerging role in reproduction and their potential to improve fertility in cattle.

Bovine β-defensin gene family: opportunities to improve animal health?

Recent analysis of the bovine genome revealed an expanded suite of β-defensin genes that encode what are referred to as antimicrobial or host defense peptides (HDPs). Whereas primate genomes also encode α- and θ-defensins, the bovine genome contains only the β-defensin subfamily of HDPs. β-Defensins perform diverse functions that are critical to protection against pathogens but also in regulation of the immune response and reproduction. As the most comprehensively studied subclass of HDPs, β-defensins possess the widest taxonomic distribution, found in invertebrates as well as plants, indicating an ancient point of origin. Cross-species comparison of the genomic arrangement of β-defensin gene repertoire revealed them to vary in number among species presumably due to differences in pathogenic selective pressures but also genetic drift. β-Defensin genes exist in a single cluster in birds, but four gene clusters exist in dog, rat, mouse, and cow. In humans and chimpanzees, one of these clusters is split in two as a result of a primate-specific pericentric inversion producing five gene clusters. A cluster of β-defensin genes on bovine chromosome 13 has been recently characterized, and full genome sequencing has identified extensive gene copy number variation on chromosome 27. As a result, cattle have the most diverse repertoire of β-defensin genes so far identified, where four clusters contain at least 57 genes. This expansion of β-defensin HDPs may hold significant potential for combating infectious diseases and provides opportunities to harness their immunological and reproductive functions in commercial cattle populations.

Meiosis and its deviations in polyploid plants

Meiosis is a fundamental process in all sexual organisms that ensures fertility and genome stability and creates genetic diversity. For each of these outcomes, the exclusive formation of crossovers between homologous chromosomes is needed. This is more difficult to achieve in polyploid species which have more than 2 sets of chromosomes able to recombine. In this review, we describe how meiosis and meiotic recombination 'deviate' in polyploid plants compared to diploids, and give an overview of current knowledge on how they are regulated. See also the sister article focusing on animals by Stenberg and Saura in this themed issue.

Correlates and characteristics of hepatitis C virus-specific T-cell immunity in exposed uninfected high-risk prison inmates

Some hepatitis C (HCV)-uninfected, high-risk individuals have HCV-specific cellular immunity without viraemia or seroconversion. The characteristics of these responses and the risk behavioural associations were studied in 94 subjects in a prospective cohort of recently seronegative prisoners reporting injecting drug use (IDU). Detailed behavioural data were collected. HCV antibody and PCR testing were performed. ELISpot assays for HCV-induced interferon (IFN)-γ and interleukin (IL)-2 production by T lymphocytes, as well as multiplex in vitro cytokine production assays, were performed. Seventy-eight subjects remained antibody and PCR negative and 16 seroconverted. Of the seronegative group, 22 (28%) had IFN-γ ELISpot responses in comparison with 13 of the 16 seroconverters (82%). This seronegative immune status was associated positively with injecting anabolic steroids and negatively with a recent break from IDU. The IFN-γ ELISpot responses involved both CD4 and CD8 T lymphocytes and were comparable in magnitude, but narrower in specificity, in uninfected subjects than in seroconverters. A subset of seronegative subjects had HCV-induced cytokine production patterns comparable with the seroconverters with increased production of IFN-γ, IL-2 and tumour necrosis factor (TNF)-α and reduced IL-10 in response to nonstructural peptides. In conclusion, comparable patterns of HCV-specific cellular immunity are found in recently infected subjects and in a minority of high-risk, uninfected subjects. Further characterization of these responses and their protective efficacy will inform HCV vaccine development.

Elicitation of health state utilities in neuroendocrine tumours

BACKGROUND

Neuroendocrine tumours (NETs) are a rare form of neoplasm that can arise in most organs of the body and which share many common pathologic features. Although curative surgery can be conducted for patients with localised disease, once progression occurs and the disease becomes metastatic or un-resectable, treatment aims to extend life and maintain quality-of-life for as long as possible. The aim of the study was to elicit utilities for health state vignettes describing the burdens associated with receiving therapy for advanced NETs.

METHODS

Health state vignettes were developed by reviewing published literature and conducting in-depth interviews with patients and clinical experts. These states described the burden associated with both stable and progressive disease, in addition to the experience of a number of serious toxicities commonly associated with treatments (grade III/IV diarrhoea, hand-foot syndrome, hyperglycaemia, nausea/vomiting, pneumonitis, rash, stomatitis, and thrombocytopenia). One hundred members of the UK general public valued the states using the time trade-off methodology to determine utility values.

RESULTS

Stable disease had a utility value of 0.77 whilst disease progression was associated with a significant decline in health-related quality-of-life (HRQoL) and a value of 0.61. Toxicities experienced in the context of stable disease exhibited varying degrees of impact, with several being deemed as debilitating as disease progression (such as hand-foot syndrome [0.58] and stomatitis [0.56]).

CONCLUSION

Although vignette studies have been criticised for the difficulty in establishing their validity, the collection of health utilities in rare populations is challenging. The findings from this study suggest that advanced NETs is associated with a considerable HRQoL burden, both as a direct result of the disease and the potential of experiencing a number of severe adverse events. These values could assist in future economic evaluation processes.