Transendothelial migration of leukocytes carrying infectious HIV-1: an indicator of adverse prognosis

Role of reverse transendothelial migration of neutrophils in inflammation

Transmigration of neutrophils through vascular endothelial walls into the inflamed tissues is a critical defense mechanism of innate immune system against infection and injury caused by sepsis, trauma, ischemia-reperfusion, and other acute or chronic inflammatory diseases. However, their excessive infiltration and uncontrolled activation may lead to the destruction of normal tissue architecture and unrestrained inflammation. Transendothelial migration (TEM) in a luminal-to-abluminal direction is widely known as the final step of neutrophil migration cascade into the inflamed tissues. Recent studies have shown that neutrophils not necessarily move from the vascular lumen to the extravascular tissues in a one way direction; they also proceed in an opposite direction, known as reverse transendothelial migration (rTEM) to get back into the vascular lumen again. This novel paradigm of neutrophil round trip is currently on the spotlight due to its possible interaction with immune system. Current review highlighting the growing demand of this newly identified neutrophil migratory event will not only rewrite the disease pathophysiology, but also help scientists design novel therapeutic strategy leading to the remission of inflammatory diseases in which controlling exaggerated neutrophil infiltration is a major challenge.

Stimuli-responsive and hemocompatible pseudozwitterionic interfaces

We report a novel biomacromolecular formula for the design of hemocompatible gel interfaces of N-isopropylacrylamide (NIPAAm) and mixed-charge pairs of [2-(methacryloyloxy)ethyl]trimethylammonium (TMA) and 3-sulfopropyl methacrylate (SA) with overall electrical neutrality. The study stresses on how well-defined compositions of nonionic NIPAAm and pseudozwitterionic TMA/SA in the poly(NIPAAm-co-TMA/SA) hydrogels along with environmental conditions (temperature, ionic strength, and solution pH) affect swelling and adhesion of biofoulants on their surfaces. When challenged with plasma proteins, bacteria, recalcified platelets, or whole blood, stimuli-responsive hydrogels better resisted their adhesion as the content of mixed charges in the copolymer increased, to reach nonbiofouling for the gels made of 100% TMA/SA. The low hemolytic activity (0.5%) associated with a long plasma clotting time (10 min) suggests excellent hemocompatibility excellent hemocompatibility. Finally, hydrogels containing both NIPAAm and TMA/SA tend to exhibit preferential adhesion of leukocytes.

Monocyte CD49e and 110-120 kDa fibronectin fragments: HIV prognostic indicators independent of viral load and CD4 T-cell counts

OBJECTIVE

To investigate the prognostic impact of chronic inflammation associated with HIV infections. Previously, we had observed that proteases, released in the course of HIV infections, cause 110-120 kDa fibronectin fragments (FNf) to appear in the blood of many patients. In vitro, at concentrations within the range found in patients' plasma, FNf stimulate monocytes to release proteolytic enzymes that remove CD49e from the cell surface and produce cytokines that suppress proliferation of activated T cells when stimulated by agents that crosslink their antigen receptors.

DESIGN

A long-term observational study of patients whose plasma FNf and monocyte CD49e had been measured at 90-day intervals for 1.4 + or - 0.5 years.

METHODS

Plasma FNf was measured by a quantitative western blot assay and monocyte CD49e expression by flow cytometry. Patients were monitored clinically for up to 5 years after enrollment.

RESULTS

All-cause mortality was significantly higher in patients who had at least 5 microg/ml FNf in more than 50% of plasma samples and/or persistent depletion of monocyte CD49e. Persistence of FNf and depletion of monocyte CD49e were not associated with changes in viral load or CD4 T-cell counts.

CONCLUSION

Persistently reduced expression of blood monocyte CD49e and/or the persistent presence of FNf in plasma are adverse prognostic markers in HIV-infected patients.

Pharmacokinetics and safety of S/GSK1349572, a next-generation HIV integrase inhibitor, in healthy volunteers

S/GSK1349572 is a novel integrase inhibitor with potent in vitro anti-HIV activity, an in vitro resistance profile different from those of other integrase inhibitors, and favorable preclinical safety and pharmacokinetics (PK). Randomized, double-blind, placebo-controlled single-dose and multiple-dose, dose escalation studies evaluated the PK, safety, and tolerability of S/GSK1349572 for healthy subjects. In the single-dose study, two cohorts of 10 subjects each (8 active, 2 receiving placebo) received suspension doses of 2, 5, 10, 25, 50, and 100 mg in an alternating panel design. In the multiple-dose study, three cohorts of 10 subjects each (8 active, 2 receiving placebo) received suspension doses of 10, 25, and 50 mg once daily for 10 days. A cytochrome P450 3A (CYP3A) substudy with midazolam was conducted with the 25-mg dose. Laboratory testing, vital signs, electrocardiograms (ECGs), and PK sampling were performed at regular intervals. S/GSK1349572 was well tolerated. Most adverse events (AEs) were mild, with a few moderate AEs reported. Headache was the most common AE. No clinically significant laboratory trends or ECG changes were noted. PK was linear over the dosage range studied. The steady-state geometric mean area under the concentration-time curve over a dosing interval (AUC(0-tau)) and maximum concentration of the drug in plasma (C(max)) ranged from 16.7 microg.h/ml (coefficient of variation [CV], 15%) and 1.5 microg/ml (CV, 24%) at a 10-mg dose to 76.8 microg.h/ml (CV, 19%) and 6.2 microg/ml (CV, 15%) at a 50-mg dose, respectively. The geometric mean steady-state concentration at the end of the dosing interval (C(tau)) with a 50-mg dose was 1.6 microg/ml, approximately 25-fold higher than the protein-adjusted 90% inhibitory concentration (0.064 microg/ml). The half-life was approximately 15 h. S/GSK1349572 had no impact on midazolam exposure, indicating that it does not modulate CYP3A activity. The PK profile suggests that once-daily, low milligram doses will achieve therapeutic concentrations.

Inflammatory and coagulation biomarkers and mortality in patients with HIV infection

BACKGROUND

In the Strategies for Management of Anti-Retroviral Therapy trial, all-cause mortality was higher for participants randomized to intermittent, CD4-guided antiretroviral treatment (ART) (drug conservation [DC]) than continuous ART (viral suppression [VS]).We hypothesized that increased HIV-RNA levels following ART interruption induced activation of tissue factor pathways, thrombosis, and fibrinolysis.

METHODS AND FINDINGS

Stored samples were used to measure six biomarkers: high sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), amyloid A, amyloid P, D-dimer, and prothrombin fragment 1+2. Two studies were conducted: (1) a nested case-control study for studying biomarker associations with mortality, and (2) a study to compare DC and VS participants for biomarker changes. For (1), markers were determined at study entry and before death (latest level) for 85 deaths and for two controls (n = 170) matched on country, age, sex, and date of randomization. Odds ratios (ORs) were estimated with logistic regression. For each biomarker, each of the three upper quartiles was compared to the lowest quartile. For (2), the biomarkers were assessed for 249 DC and 250 VS participants at study entry and 1 mo following randomization. Higher levels of hsCRP, IL-6, and D-dimer at study entry were significantly associated with an increased risk of all-cause mortality. Unadjusted ORs (highest versus lowest quartile) were 2.0 (95% confidence interval [CI], 1.0-4.1; p = 0.05), 8.3 (95% CI, 3.3-20.8; p < 0.0001), and 12.4 (95% CI, 4.2-37.0; p < 0.0001), respectively. Associations were significant after adjustment, when the DC and VS groups were analyzed separately, and when latest levels were assessed. IL-6 and D-dimer increased at 1 mo by 30% and 16% in the DC group and by 0% and 5% in the VS group (p < 0.0001 for treatment difference for both biomarkers); increases in the DC group were related to HIV-RNA levels at 1 mo (p < 0.0001). In an expanded case-control analysis (four controls per case), the OR (DC/VS) for mortality was reduced from 1.8 (95% CI, 1.1-3.1; p = 0.02) to 1.5 (95% CI, 0.8-2.8) and 1.4 (95% CI, 0.8-2.5) after adjustment for latest levels of IL-6 and D-dimer, respectively.

CONCLUSIONS

IL-6 and D-dimer were strongly related to all-cause mortality. Interrupting ART may further increase the risk of death by raising IL-6 and D-dimer levels. Therapies that reduce the inflammatory response to HIV and decrease IL-6 and D-dimer levels may warrant investigation.

Pharmacokinetics and safety of indinavir in human immunodeficiency virus-infected pregnant women

Human immunodeficiency virus-infected women (n=16) received indinavir (800 mg three times a day) plus zidovudine plus lamivudine from 14 to 28 weeks of gestation to 12 weeks postpartum. Two women and eight infants experienced grade 3 or 4 toxicities that were possibly treatment related. Indinavir area under the plasma concentration-time curve was 68% lower antepartum versus postpartum, suggesting increased intestinal and/or hepatic CYP3A activity during pregnancy.

Lack of pharmacokinetic drug interaction between tenofovir disoproxil fumarate and nelfinavir mesylate

A study explored the pharmacokinetics of tenofovir (300 mg administered once daily) and nelfinavir (1,250 mg twice daily) when coadministered in 29 healthy volunteers. Tenofovir, nelfinavir, and M8 pharmacokinetics was unaltered when tenofovir and nelfinavir were coadministered, and tenofovir administration did not affect the M8/nelfinavir area under the concentration-versus-time curve over the dosing interval (AUC(tau)) ratio. No interaction between tenofovir and nelfinavir was observed.

Evidence of genetic variability of human immunodeficiency virus type 1 in plasma and cervicovaginal lavage in ethiopian women seeking care for sexually transmitted infections

Most human immunodeficiency virus type 1 (HIV-1) transmission in developing countries occurs through heterosexual intercourse or during birth from mother to child. It is critical to characterize the virus of the genital tract variants as a target for the development of an HIV-1 vaccine and microbicidal therapies. We compared the C2V3 env domain genetic diversity of HIV-1 in female genital secretions and in plasma from Ethiopian women seeking care for sexually transmitted infections (STIs). Sequences within an individual differed between the plasma and cervicovaginal lavage (CLV) compartments with nucleotide and amino acid median difference values of 8.3 and 4.8%, respectively. Sequence diversity in CVL was greater than in plasma. And the V3 loop positive charge was often more elevated in CVL. These are markers of the differential evolution of the viruses in CVL and peripheral blood indicating that limited evolution at the site of contact is not the limiting factor determining the preferential transmission of macrophage tropic viruses.

Steady-state pharmacokinetics of a double-boosting regimen of saquinavir soft gel plus lopinavir plus minidose ritonavir in human immunodeficiency virus-infected adults

Management of treatment-experienced human immunodeficiency virus patients has become complex, and therapy may need to include two protease inhibitors at therapeutic doses. The objective of this study was to characterize the pharmacokinetics in serum of saquinavir (1,000 mg twice daily [b.i.d.]), lopinavir (400 mg b.i.d.), and ritonavir (100 mg b.i.d.) in a multidrug rescue therapy study and to investigate whether steady-state pharmacokinetics of lopinavir-ritonavir are affected by coadministration of saquinavir. Forty patients were included (25 given ritonavir, lopinavir, and saquinavir and 15 given ritonavir and lopinavir). The median pharmacokinetic parameters of lopinavir were as follows: area under the concentration-time curve from 0 to 12 h (AUC(0-12)), 85.1 microg/ml . h; maximum concentration of drug in serum (C(max)), 10.0 microg/ml; trough concentration of drug in serum (C(trough)), 7.3 microg/ml; and minimum concentration of drug in serum (C(min)), 5.5 microg/ml. Lopinavir concentrations were similar in patients with and without saquinavir. The median pharmacokinetic parameters for saquinavir were as follows: AUC(0-12), 22.9 microg/ml . h; C(max), 2.9 microg/ml; C(trough), 1.6 microg/ml; and C(min), 1.4 microg/ml. There was a strong linear correlation between lopinavir and ritonavir and between saquinavir and ritonavir concentrations in plasma. The correlation between lopinavir and saquinavir levels was weaker. We found higher saquinavir concentrations in women than in men, with no difference in lopinavir levels. Only patients with very high body weight presented lopinavir and saquinavir concentrations lower than the overall group. Ritonavir has a double-boosting function for both lopinavir and saquinavir, and in terms of pharmacokinetics, the drug doses selected seemed appropriate for combining these agents in a dual protease inhibitor-based antiretroviral regimen for patients with several prior virologic failures.

Monocyte activation by circulating fibronectin fragments in HIV-1-infected patients

To identify signals that can alter leukocyte function in patients receiving highly active antiretroviral therapy (HAART), we analyzed single blood samples from 74 HIV-1-infected patients and additional blood was collected at 90-day intervals from 51 HIV-1-infected patients over a 516 +/- 172 (mean +/- SD) day interval. Despite the absence of circulating immune complexes and normalization of phagocytic function, compared with controls, the fraction of patients' monocytes expressing CD49e and CD62L was decreased and expression of CD11b and CD86 increased. Plasma from 63% of patients but none from normal controls contained 110-120 kDa fibronectin fragments (FNf). Presence of FNf did not reflect poor adherence to therapy. Addition of FNf to normal donor blood in vitro replicated changes in monocyte CD49e, CD62L, CD11b, and CD86 seen in vivo. FNf also induced monocytes to release a serine proteinase, nominally identified as proteinase-3, that hydrolyzed cell surface CD49e. alpha(1)-Antitrypsin blocked FNf-induced shedding of CD49e in a dose-dependent manner. Plasma with a normal frequency of CD49e(+) monocytes contained antiproteases that partially blocked FNf-induced monocyte CD49e shedding, whereas plasma from patients with a low frequency of CD49e(+) monocytes did not block this effect of FNf. Electrophoretic analyses of plasma from the latter group of patients suggested that a significant fraction of their alpha(1)-antitrypsin was tied up in high molecular mass complexes. These results suggest that monocyte behavior in HIV-1-infected patients may be influenced by FNf and the ratio of protease and antiproteases in the cells' microenvironment.

Impact of fibronectin fragments on the transendothelial migration of HIV-infected leukocytes and the development of subendothelial foci of infectious leukocytes

Leukocyte infiltrates that can serve as viral reservoirs, and sites for viral replication are found in many organs of HIV-1-infected patients. Patients whose blood leukocytes migrate across confluent endothelial monolayers ex vivo and transmit infectious virus to mononuclear leukocytes (MNLs) lodged beneath this endothelial barrier have a worse prognosis. We evaluated the ability of 110- to 120-kDa fibronectin fragments (FNf), which are found in the blood of >60% of HIV-1-infected patients, to stimulate transendothelial migration and drive productively infected MNLs into a potential perivascular space. FNf induced MNLs to release TNF-alpha in a dose-dependent fashion; the resulting increase in lymphocyte and monocyte transendothelial migration could be blocked with soluble TNF receptor I. Rather than penetrate deeply into the subendothelial matrix, as is seen with untreated controls, FNf-treated MNLs clustered just below the endothelial monolayer. Treatment with FNf during migration increased subsequent recovery of HIV-infected cells from the subendothelial compartment. FNf treatment also significantly increased the numbers of HLA-DR(bright), dendritic-type cells that reverse-migrated from the subendothelial depot to the apical endothelial surface 48 h after migration. Fibronectin fragments can be produced by viral and host proteases in the course of inflammatory conditions. The ability of FNf to stimulate transendothelial migration of HIV-1-infected MNLs may help to explain the dissemination of this infection into cardiac, renal, and CNS tissues.

Determination of ddATP levels in human immunodeficiency virus-infected patients treated with dideoxyinosine

Clinical failures of the highly active antiretroviral therapy could result from inefficient intracellular concentrations of antiviral drugs. The determination of drug contents in target cells of each patient would be useful in clinical investigations and trials. The purpose of this work was to quantify the intracellular concentration of ddATP, the active metabolite of dideoxyinosine (ddI), in peripheral blood mononuclear cells (PBMCs) of human immunodeficiency virus (HIV)-infected patients treated with ddI. We have raised antibodies against ddA-citrate, a stable isostere of ddATP selected on the basis of its structural and electronic analogies with ddATP. The anti-ddA-citrate antibodies recognized ddATP and ddA with nanomolar affinities and cross-reacted neither with any of the nucleotide reverse transcriptase inhibitors used in HIV therapy nor with their phosphorylated metabolites. The three phosphorylated metabolites of ddI (ddAMP, ddADP, and ddATP) were purified by anion exchange chromatography and the amount of each metabolite was determined by radioimmunoassay with or without prior phosphatase treatment. The intracellular levels of the three ddI metabolites were measured both in an in vitro model and in PBMCs of HIV-infected patients under ddI treatment. The possibility to measure intracellular levels of ddATP from small blood samples of HIV-infected patients treated with ddI could be exploited to develop individual therapeutic monitoring.