Simian immunodeficiency virus (SIV)-specific CTL are present in large numbers in livers of SIV-infected rhesus monkeys

The immunopathogenesis of AIDS-associated hepatitis was explored in the SIV/rhesus monkey model. The livers of SIV-infected monkeys showed a mild hepatitis, with a predominantly CD8+ T lymphocyte infiltration in the periportal fields and sinusoids. These liver-associated CD8+ T cells were comprised of a high percentage of SIV-specific CTL as defined by MHC class I/Gag peptide tetramer binding and Gag peptide epitope-specific lytic activity. There was insufficient viral replication in these livers to account for attracting this large number of functional virus-specific CTL to the liver. There was also no evidence that the predominant population of CTL were functionally end-stage cells trapped in the liver and destined to undergo apoptotic cell death in that organ. Interestingly, we noted that liver tetramer-binding cells showed an increased expression of CD62L, an adhesion molecule usually only rarely expressed on tetramer-binding cells. This observation suggests that the expression of specific adhesion molecules by CTL might facilitate the capture of these cells in the liver. These results demonstrate that functional SIV-specific CD8+ T cells are present in large numbers in the liver of chronically SIV-infected monkeys. Thus, the liver may be a trap for virus-specific cytotoxic T cells.     

Antioxidant levels in the rat brain after nitric oxide synthase inhibition: a preliminary report

Protective effects of NOS inhibitors and free radical scavengers in cerebral ischemia are well documented. The present study was undertaken to determine the possible effects of NOS inhibition on brain antioxidants. Levels of both enzymatic [glutathione peroxidase (GPx), catalase and superoxide dismutase (SOD)] and non-enzymatic [reduced glutathione (GSH)] antioxidants following nitric oxide synthase (NOS) inhibition by N(G)-nitro-L-arginine methyl ester (L-NAME), D-NAME or 7-nitroindazole (7-NI) have been investigated. NOS activity and antioxidant levels in the rat cerebellum and medulla were estimated 1 h after treatment with L-NAME (10, 30 and 100 mg/kg, i.p.), D-NAME (100 mg/kg, i.p.) or 7-NI (25 mg/kg, i.p.). L-NAME and 7-NI inhibited NOS activity in a dose-dependent manner. D-NAME also exhibited significant NOS inhibition. The activity of SOD and the GSH level remained unaltered following NOS inhibition. However, L-NAME and D-NAME at 100 mg/kg attenuated GPx activity in the cerebellum, though 7-NI had no effect. L-NAME inhibited catalase activity in medulla only at 30 mg/kg, but had no effect in cerebellum. However, 7-NI (25 mg/kg), D-NAME and L-NAME at 100 mg/kg did not affect catalase activity in the rat brain. Thus, NOS inhibition by the three agents did not have major effects on brain antioxidant levels.     

p27(Kip1) is an inducer of intestinal epithelial cell differentiation

Constant renewal of the intestinal epitheliumis a highly coordinated process that has been subject to intenseinvestigation, but its regulatory mechanisms are still essentiallyunknown. In this study, we have demonstrated that forced expression ofthe cyclin-dependent kinase inhibitors (CKIs) p27^Kip1 andp21^Cip1/WAF1 in human intestinal epithelial cells led toexpression of differentiation markers at both the mRNA and proteinlevels. Cell differentiation was temporally dissociated from inhibitionof retinoblastoma protein phosphorylation and growth arrest, alreadyestablished 1 day after infection with recombinant adenoviruses.p27^Kip1 proved significantly more efficient thanp21^Cip1/WAF1 in induction of cell differentiation. Incontrast, forced expression of p16^INK4a resulted in growtharrest without induction of differentiation markers. These resultsimplicate both p27^Kip1 and p21^Cip1/WAF1 in thedifferentiation-timing process, but p21^Cip1/WAF1 may actindirectly by increasing p27^Kip1 levels. These results alsosuggest that induction of intestinal epithelial cell differentiation byCKIs is not related to their effects on the cell cycle and may involveinteractions with cellular components other than cyclins andcyclin-dependent kinases.

     

Cost-Effectiveness of Coronary Artery Calcium Testing for Coronary Heart and Cardiovascular Disease Risk Prediction to Guide Statin Allocation: The Multi-Ethnic Study of Atherosclerosis (MESA)

Background

The Multi-Ethnic Study of Atherosclerosis (MESA) showed that the addition of coronary artery calcium (CAC) to traditional risk factors improves risk classification, particularly in intermediate risk asymptomatic patients with LDL cholesterol levels <160 mg/dL. However, the cost-effectiveness of incorporating CAC into treatment decision rules has yet to be clearly delineated.

Objective

To model the cost-effectiveness of CAC for cardiovascular risk stratification in asymptomatic, intermediate risk patients not taking a statin. Treatment based on CAC was compared to (1) treatment of all intermediate-risk patients, and (2) treatment on the basis of United States guidelines.

Methods

We developed a Markov model of first coronary heart disease (CHD) and cardiovascular disease (CVD) events. We modeled statin treatment in intermediate risk patients with CAC≥1 and CAC≥100, with different intensities of statins based on the CAC score. We compared these CAC-based treatment strategies to a “treat all” strategy and to treatment according to the Adult Treatment Panel III (ATP III) guidelines. Clinical and economic outcomes were modeled over both five- and ten-year time horizons. Outcomes consisted of CHD and CVD events and Quality-Adjusted Life Years (QALYs). Sensitivity analyses considered the effect of higher event rates, different CAC and statin costs, indirect costs, and re-scanning patients with incidentalomas.

Results

We project that it is both cost-saving and more effective to scan intermediate-risk patients for CAC and to treat those with CAC≥1, compared to treatment based on established risk-assessment guidelines. Treating patients with CAC≥100 is also preferred to existing guidelines when we account for statin side effects and the disutility of statin use.

Conclusion

Compared to the alternatives we assessed, CAC testing is both effective and cost saving as a risk-stratification tool, particularly if there are adverse effects of long-term statin use. CAC may enable providers to better tailor preventive therapy to patients'' risks of CVD.     

AUDIT,AUDIT-C,and AUDIT-3: Drinking Patterns and Screening for Harmful,Hazardous and Dependent Drinking in Katutura,Namibia

Objectives

To describe alcohol drinking patterns among participants in Katutura, Namibia, and to evaluate brief versions of the AUDIT against the full AUDIT to determine their effectiveness in detecting harmful drinking.

Methods

A cross-sectional survey was conducted in four constituencies and 639 participants, 18 years or older, completed a sociodemographic survey and the AUDIT. The effectiveness of the AUDIT-C (first three questions) and the AUDIT-3 (third question) was compared to the full AUDIT.

Results

Approximately 40% were identified as harmful, hazardous or likely dependent drinkers, with men having a higher likelihood than women (57.2% vs. 31.0%, p<.0001). Approximately 32% reported making and/or selling alcohol from home. The AUDIT-C performed best at a cutoff ≥ 3, better in men (sensitivity: 99.3%, specificity: 77.8%) than women (sensitivity: 91.7%, specificity: 77.4%). The AUDIT-3 performed poorly (maximum sensitivity: < 90%, maximum specificity: <51%). According to AUROC, the AUDIT-C performed better than the AUDIT-3.

Conclusions

A large proportion of participants met criteria for alcohol misuse, indicating a need for screening and referral for further evaluation and intervention. The AUDIT-C was almost as effective as the full AUDIT and may be easier to implement in clinical settings as a routine screening tool in resource-limited settings because of its brevity.     

Non-Carrier Nanoparticles Adjuvant Modular Protein Vaccine in a Particle-Dependent Manner

Nanoparticles are increasingly used to adjuvant vaccine formulations due to their biocompatibility, ease of manufacture and the opportunity to tailor their size, shape, and physicochemical properties. The efficacy of similarly-sized silica (Si-OH), poly (D,L-lactic-co-glycolic acid) (PLGA) and poly caprolactone (PCL) nanoparticles (nps) to adjuvant recombinant capsomere presenting antigenic M2e modular peptide from Influenza A virus (CapM2e) was investigated in vivo. Formulation of CapM2e with Si-OH or PLGA nps significantly boosted the immunogenicity of modular capsomeres, even though CapM2e was not actively attached to the nanoparticles prior to injection (i.e., formulation was by simple mixing). In contrast, PCL nps showed no significant adjuvant effect using this simple-mixing approach. The immune response induced by CapM2e alone or formulated with nps was antibody-biased with very high antigen-specific antibody titer and less than 20 cells per million splenocytes secreting interferon gamma. Modification of silica nanoparticle surface properties through amine functionalization and pegylation did not lead to significant changes in immune response. This study confirms that simple mixing-based formulation can lead to effective adjuvanting of antigenic protein, though with antibody titer dependent on nanoparticle physicochemical properties.     

Upregulation of miR21 and Repression of Grhl3 by Leptin Mediates Sinusoidal Endothelial Injury in Experimental Nonalcoholic Steatohepatitis

Sinusoidal endothelial dysfunction (SED) has been found to be an early event in nonalcoholic steatohepatitis (NASH) progression but the molecular mechanisms underlying its causation remains elusive. We hypothesized that adipokine leptin worsens sinusoidal injury by decreasing functionally active nitric oxide synthase 3 (NOS)3 via miR21. Using rodent models of NASH, and transgenic mice lacking leptin and leptin receptor, results showed that hyperleptinemia caused a 4–5 fold upregulation of hepatic miR21 as assessed by qRTPCR. The upregulation of miR21 led to a time-dependent repression of its target protein Grhl3 levels as shown by western blot analyses. NOS3-p/NOS3 ratio which is controlled by Grhl3 was significantly decreased in NASH models. SED markers ICAM-1, VEGFR-2, and E-selectin as assessed by immunofluorescence microscopy were significantly up regulated in the progressive phases of NASH. Lack of leptin or its receptor in vivo, reversed the upregulation of miR21 and restored the levels of Grhl3 and NOS3-p/NOS3 ratio coupled with decreased SED dysfunction markers. Interestingly, leptin supplementation in mice lacking leptin, significantly enhanced miR21 levels, decreased Grhl3 repression and NOS3 phosphorylation. Leptin supplementation in isolated primary endothelial cells, Kupffer cells and stellate cells showed increased mir21 expression in stellate cells while sinusoidal injury was significantly higher in all cell types. Finally miR21 KO mice showed increased NOS3-p/NOS3 ratio and reversed SED markers in the rodent models of NASH. The experimental results described here show a close association of leptin-induced miR21 in aiding sinusoidal injury in NASH.