Beyond the gut bacterial microbiota: The gut virome.

The gastrointestinal tract is colonized with a highly different population of bacterial, viral, ad fungal species; viruses are reported to be dominant. The composition of gut virome is closely related to dietary habits and surrounding environment. Host and their intestinal microbes live in a dynamic equilibrium and viruses stimulate a low degree of immune responses without causing symptoms (host tolerance). However, intestinal phages could lead to a rupture of eubiosis and may contribute to the shift from health to disease in humans and animals. Viral nucleic acids and other products of lysis of bacteria serve as pathogen-associated molecular patterns (PAMPs) and could trigger specific inflammatory modulations. At the same time, phages could elicit innate antiviral immune responses. Toll-like receptors (TLRs) operated as innate antiviral immune sensors and their activation triggers signaling cascades that lead to inflammatory response. J. Med. Virol. 88:1467-1472, 2016. © 2016 Wiley Periodicals, Inc.

gp120 modulates the biology of human hepatic stellate cells: a link between HIV infection and liver fibrogenesis.

OBJECTIVE: In patients with hepatitis C virus (HCV)/HIV co-infection, a faster progression of liver fibrosis to cirrhosis has been reported. In this study, an investigation was carried out to determine whether gp120, an HIV envelope protein, modulates the biology of human hepatic stellate cells (HSCs), key cell types in the pathogenesis of fibrosis. METHODS: Myofibroblastic HSCs were isolated from normal human liver tissue. Gene expression was measured by real-time PCR. Cell migration was assessed in Boyden chambers. Intracellular signalling pathways were evaluated using phosphorylation-specific antibodies or by transfection of a reporter plasmid. RESULTS: Transcripts for the chemokine receptors CCR5 and CXCR4, which bind gp120, were detectable in human HSCs. Upon exposure to M-tropic recombinant gp120, which binds CCR5, a significant increase in HSC chemotaxis was observed (1.6+/-0.3-fold, p=0.03). The effects of gp120 were prevented by protein inactivation. gp120 also resulted in a significant increase in secretion (1.5+/-0.3-fold, p=0.03) and gene expression (1.47+/-0.13-fold, p=0.02) of the proinflammatory chemokine monocyte chemoattractant protein-1, and in increased gene expression of tissue inhibitor of metalloprotease-1 and interleukin-6 (2.03+/-0.57-fold, p=0.02). gp120-induced migration required Akt activation. gp120 also induced activation of nuclear factor-kappaB (NF-kappaB) and p38(MAPK). Preincubation of HSCs with TAK779, a CCR5 receptor antagonist, prevented gp120-mediated chemotaxis and monocyte chemoattractant protein-1 secretion. Expression of CCR5 was detectable in areas of inflammation and fibrogenesis in liver biopsies of patients with HCV/HIV co-infection. CONCLUSIONS: This study shows that HIV gp120 modulates different aspects of HSC biology, including directional cell movement and expression of proinflammatory cytokines. These results identify a direct pathway possibly linking HIV infection with liver fibrogenesis via envelope proteins.

Pathogenesis of liver damage in HCV-HIV patients.

The coinfection of HIV and HCV has become a pathology with several distinctive characteristics. Pathogenesis of liver damage in patients with HIV and HCV coinfection is complex and multifactorial. It derives from a balance of factors which interact among themselves in a dynamic way. The reasons for the accelerated course of HIV/HCV coinfection are mainly related to two principal causes: the persistence of HCV, which depends upon alterations of cell-mediated immunity, and the activation of the immune system towards secretion of proinflammatory and profibrotic cytokines. This review will first focus on the characteristics of both these immune-mediated mechanisms, and then their implication on fibrogenesis as well as on other pathogenetic mechanisms, such as interactions between viruses and the deficit of protective mechanisms. A better knowledge of adaptive immune mechanisms, cytokine alteration, interference with host defense mechanisms, and the "cross-talk" among the viruses will improve the understanding of the pathogenetic mechanism and provide the opportunity to cure this disease.

Salvage therapy or simplification of salvage regimens with dolutegravir plus ritonavir-boosted darunavir dual therapy in highly cART-experienced subjects: an Italian cohort.

BACKGROUND: Dolutegravir plus darunavir provide a high genetic barrier to HIV-1 resistance and are suitable for simple salvage regimens. METHODS: All HIV-1-infected subjects treated with dolutegravir plus boosted darunavir dual therapy between March 2011 and September 2015 were included in an observational cohort. Data were collected at baseline and at weeks 4, 12, 24 and 48. RESULTS: We enrolled 113 subjects. After week 24, one was lost at follow-up, one dropped out for grade 2 elevation of liver enzymes, one died from illicit drug abuse and one from cancer-related sepsis. The mean age was 51, 26.5% were female and 9.7% were non-Caucasian. Twenty had never experienced failure. A total of 99 had reverse-transcriptase (RT) mutations, 87 had protease inhibitor mutations and 12 had integrase strand transfer inhibitor (INSTI) mutations. Viraemic patients declined from baseline to week 24 from 43.4% to 6.2%, the remainder being due to high baseline viraemia or adherence issues. The proportion of subjects with viraemia 1-49 copies/ml remained at 20.4% while those in whom no virus was detected (NVD) increased from 36.3% to 73.5% by week 24. All the 47 subjects who had a 48-week follow-up had <50 copies/ml and 42 (89.4%) had NVD. 18 subjects had reduced sensitivity to darunavir (Stanford median score 15, range 15-40), but none rebounded, 6 having a 24-week and 7 a 48-week follow-up. The median variation in serum creatinine was -0.01 (range +0.2 to -0.21) mg/dl. CONCLUSIONS: This dual regimen provides a simple salvage regimen and proved safe and effective in this cohort.

Understanding the Mechanisms of Fibrogenesis in HIV/HCV-Coinfected Patients: Implications for Clinical Practice.

HIV/HCV coinfection is associated with accelerated progressive liver disease. Understanding the pathogenesis of liver fibrosis remains crucial to improving the global management of this patient population. This review will mainly focus on the mechanisms involved in the faster progression of liver fibrosis seen in HIV/HCV coinfection, which is caused by a multiplicity of complex factors including virus features, the immune system, interactions between viruses and the immune response, the direct effects of HIV on hepatocytes, fibrinogenetic/inflammatory mediators, microbial translocation, and metabolic abnormalities. The direct role of viruses as well as chronic inflammation, deterioration of immune status, and the harmful effect of antiretroviral agents may all concur to produce dyslipidemia and insulin resistance. Metabolic abnormalities play an important role in the genesis of hepatic steatosis, which is closely linked to liver fibrosis progression. There is also a link between immunologic and metabolic abnormalities: increased expression of leptin and reduced expression of adiponectin seems to be associated with advanced hepatic injury. New antifibrotic strategies are outlined. Ultimately, sustained virological response to hepatitis C therapy is associated with liver fibrosis regression in patients with HIV/HCV coinfection.

Liver fibrosis, microbial translocation and immune activation markers in HIV and HCV infections and in HIV/HCV co-infection.

BACKGROUND: Liver fibrosis is accelerated in patients co-infected with human immunodeficiency virus and hepatitis C viruses. AIMS: We investigated the correlation between liver fibrosis, immune activation and microbial translocation. METHODS: This cross-sectional study included patients with hepatitis C virus (HCV) and human immunodeficiency virus (HIV) mono-infections, HIV/HCV co-infection, and healthy controls (20 subjects/group). Peripheral blood was analysed to determine the levels of Forkhead box 3 (Foxp3) T cells, TGF-ß1, CD14 (soluble and surface isoforms), IL-17 and bacterial translocation products. These measurements were correlated to the severity of liver fibrosis, measured with the FIB-4 score and transient elastography. RESULTS: Foxp3T cell levels were significantly elevated in HIV mono-infected and co-infected groups (p<0.0005). FIB-4 and liver stiffness values inversely correlated with TGF-ß1 (p=0.0155 and p=0.0498). Bacterial DNA differed significantly in the HIV-positive compared to the other groups: HIV/HCV co-infected subjects had significantly higher serum levels of bacterial translocation products, CD14, and IL-17 levels (p<0.001). CONCLUSIONS: Fibrosis stage in HIV/HCV co-infection may be influenced by immune activation due either by viral infections or to bacterial translocation.

Forecast model for the evaluation of economic resources employed in the health care of patients with HIV infection.

BACKGROUND AND AIMS: The total health care cost for human immunodeficiency virus (HIV) patients has constantly grown in recent years. To date, there is no information about how this trend will behave over the next few years. The aim of the present study is to define a pharmacoeconomic model for the forecast of the costs of a group of chronically treated patients followed over the period 2004-2009. METHODS: A pharmacoeconomics model was built to describe the probability of transition among different health states and to modify the therapy over time. A Markov model was applied to evaluate the temporal evolution of the average cost. The health care resources exploited during hospitalization were analyzed by using an "activity-based costing" method. RESULTS: The Markov model showed that the mean total cost, after an initial increase, tended to remain stable. A total of 20 clinical records were examined. The average daily cost for each patient was EUR 484.42, with a cost for admission of EUR 6781.88. CONCLUSION: The treatment of HIV infection in compliance with the guidelines is also effective from the payer perspective, as it allows a good health condition to be maintained and reduces the need and the costs of hospitalizations.

Forthcoming challenges in the management of direct-acting antiviral agents (DAAs) for hepatitis C.

Agents that specifically target the replication cycle of the virus direct-acting antiviral agents (DAAs) by directly inhibiting the NS3/4A serine protease, the NS5B polymerase and NS5A are currently in clinical development. The need to achieve serum drug concentrations able to suppress viral replication is a key factor for a successful antiviral therapy and the prevention of resistance. Thus pharmacokinetics parameters became important issues for drugs used in the therapy of hepatitis C. The ratio of C(min)/IC(50) (inhibitory quotient or IQ) can provide a surrogate measure of a drug's ability to suppress HCV replication, by taking into account the relationship between plasma drug levels and viral susceptibility to the drug. Ritonavir boosting may be a useful strategy to improve pharmacokinetic parameters. Characterising resistance to DAAs in clinical trials is essential for the management of a drug regimen to reduce the development of resistance and thereby maximise SVR rate. The lesson of HIV therapy, provide a compelling case for the exploration of combinations of direct-acting antiviral agents.

Correlation between FIB4, liver stiffness and metabolic parameters in patients with HIV and hepatitis C virus co-infection.

BACKGROUND/AIMS: Assessment of liver fibrosis is crucial in HIV/HCV coinfected patients, in whom metabolic disturbances are frequent. Aims of this study were to analyse the association of two non-invasive liver fibrosis evaluation methods, liver stiffness measurement and FIB4, and their correlation with metabolic parameters. METHODS: This was a single centre cross-sectional study. All patients underwent biochemical and virological assessment, FIB4 score, HOMA and transient elastography. RESULTS: Seventy-five patients were evaluated. Liver stiffness values positively correlated with FIB4 (R = 0.62; p < 0.0001). By ROC curve analysis the optimal cut-off for liver stiffness to identify high FIB4 was calculated as 10.1 kPa. The area under the ROC curve was 0.78 (95% CI 0.78-0.94, sensitivity 83.3%, specificity 80.7%). Liver stiffness values positively correlated with HOMA score (R = 0.31; p = 0.006). CONCLUSIONS: The combination of two non invasive tools provide a useful system for the assessment of fibrosis evolution in patients with HIV-HCV coinfection.