Laser Microirradiation to Study In Vivo Cellular Responses to Simple and Complex DNA Damage.

DNA damage induces specific signaling and repair responses in the cell, which is critical for protection of genome integrity. Laser microirradiation became a valuable experimental tool to investigate the DNA damage response (DDR) in vivo. It allows real-time high-resolution single-cell analysis of macromolecular dynamics in response to laser-induced damage confined to a submicrometer region in the cell nucleus. However, various laser conditions have been used without appreciation of differences in the types of damage induced. As a result, the nature of the damage is often not well characterized or controlled, causing apparent inconsistencies in the recruitment or modification profiles. We demonstrated that different irradiation conditions (i.e., different wavelengths as well as different input powers (irradiances) of a femtosecond (fs) near-infrared (NIR) laser) induced distinct DDR and repair protein assemblies. This reflects the type of DNA damage produced. This protocol describes how titration of laser input power allows induction of different amounts and complexities of DNA damage, which can easily be monitored by detection of base and crosslinking damages, differential poly (ADP-ribose) (PAR) signaling, and pathway-specific repair factor assemblies at damage sites. Once the damage conditions are determined, it is possible to investigate the effects of different damage complexity and differential damage signaling as well as depletion of upstream factor(s) on any factor of interest.

Serum immune activation markers are persistently increased in patients with HIV infection after 6 years of antiretroviral therapy despite suppression of viral replication and reconstitution of CD4+ T cells.

The effect of long-term antiretroviral therapy on serum immune activation markers was assessed in a cohort of 63 patients before and after 6 years of boosted lopinavir-based antiretroviral therapy. High levels of most markers were associated with lower CD4(+) T cell counts at baseline and at year 6, with the exception of soluble cytotoxic T lymphocyte antigen-4 (sCTLA-4); high levels of sCTLA-4 were associated with higher CD4(+) T cell counts at year 6. Abnormalities of serum immune activation markers persisted after 6 years of ART but probably had different causes. Further investigation of the clinical usefulness of assaying immunoglobulin A, neopterin, and sCTLA-4 levels to assess the effectiveness of treatments for human immunodeficiency virus (HIV) disease are warranted.

Loss of bone mineral density after antiretroviral therapy initiation, independent of antiretroviral regimen.

BACKGROUND: Decreased bone mineral density (BMD) has been described in HIV-infected patients initiating antiretroviral therapy (ART), but the contributions of ART and immunologic and/or virologic factors remain unclear. METHODS: We compared total BMD changes over 96 weeks in 106 ART-naive HIV-infected subjects who were randomized to receive efavirenz (EFV) + zidovudine/lamivudine (n = 32) or lopinavir/ritonavir (LPV/r) + zidovudine/lamivudine induction (n = 74) for 24-48 weeks followed by LPV/r monotherapy. We also sought to identify factors associated with BMD loss, including markers of systemic inflammation [soluble tumor necrosis factor-alpha receptors (sTNFR I and II)]. RESULTS: After 96 weeks, the mean percent change from baseline in total BMD was -2.5% (LPV/r) and -2.3% (EFV) (P < 0.01 for within-group changes in either arm; P = 0.86 for between-group differences). No alteration in the rate of BMD change was observed upon simplification to LPV/r monotherapy. Although soluble tumor necrosis factor-alpha receptor II concentrations at baseline and 24 weeks were at least marginally associated with subsequent changes in BMD (P = 0.06 and P = 0.028, respectively), these associations were no longer significant after adjustment for CD4 T cell count. Subjects with lower baseline CD4 T cell count, non-black race, and higher baseline glucose demonstrated a higher risk for >5% decrease in BMD. CONCLUSIONS: Similar decreases in BMD over 96 weeks occurred in ART-naive subjects receiving either EFV-based regimen or LPV/r-based regimen, which was not altered by simplification to LPV/r monotherapy and was unrelated to markers of tumor necrosis factor-alpha activity.

Geographic and temporal trends of transmitted HIV-1 drug resistance among antiretroviral-naïve subjects screening for two clinical trials in North America and Western Europe.

PURPOSE: To determine the prevalence of transmitted drug resistance (TDR) in antiretroviral (ARV)-naïve HIV-1-infected subjects who were screened for two clinical trials by geographic region and time. METHODS: Studies M03-613 and M05-730 screened ARV-naïve subjects in 2004 and 2005-2006, respectively. Screening drug resistance genotype assays were performed using population sequencing, and prevalence of drug resistance mutations (DRMs) was assessed at 39 amino acid positions in HIV-1 protease and reverse transcriptase (RT) and compared between geographic regions and calendar years. RESULTS: In 913 subjects, the prevalence of DRMs was higher in North America than in Western Europe, including any DRM (13.6% vs. 6.8%, p < .001), non-nucleoside reverse transcriptase inhibitor (NNRTI) DRMs (7.3% vs. 3.2%, p = .006), protease inhibitor (PI) DRMs (3.6% vs. 0.8%, p = .004), and nucleoside reverse transcriptase inhibitor (NRTI) DRMs (6.1% vs. 3.8%, p = ns). The prevalence of TDR to NNRTIs was higher compared to PIs within each region (p = .031 for North America, and p = .011 for Western Europe). Logistic regression analysis suggested a higher prevalence of DRMs in 2005-2006 compared to 2004 for NNRTIs (p = .03) and, to a lesser extent, for PIs (p = .07). CONCLUSION: TDR to NNRTIs was more frequent than to PIs in both geographic regions, increased over time, and was highest in North America.

Predictors of loss of virologic response in subjects who simplified to lopinavir/ritonavir monotherapy from lopinavir/ritonavir plus zidovudine/lamivudine.

Previous studies have demonstrated that lopinavir/ritonavir monotherapy maintained plasma HIV-1 RNA suppression in a large proportion of antiretroviral naive subjects. However, more subjects receiving lopinavir/ritonavir monotherapy experienced confirmed virologic rebound >50 copies/ml compared to a standard three-drug HAART regimen. In this study, we sought to determine the factors associated with maintenance of virologic suppression in subjects receiving lopinavir/ritonavir monotherapy. Antiretroviral-naive HIV-1-infected volunteers were randomized 2:1 to initiate a lopinavir/ritonavir-based combination regimen followed by simplification to lopinavir/ritonavir monotherapy or an efavirenz-based triple combination therapy and followed for 96 weeks. Potential predictors of time to loss of virologic response included baseline demographics, baseline HIV-1 RNA levels, baseline CD4(+) T cell counts, adherence as determined by 4-day subject recall, duration of HIV-1 RNA <50 copies/ml prior to simplification, and lopinavir concentrations. By the Cox proportional hazards model, higher reported adherence levels and higher baseline CD4(+) T cell counts were associated with a greater likelihood of maintaining virologic suppression while receiving lopinavir/ritonavir monotherapy. Lopinavir concentrations, including trough concentrations, were not significantly associated with virologic outcomes. This analysis suggests that adherence and higher baseline CD4(+) T cell counts may help to predict who will sustain virologic suppression with lopinavir/ritonavir monotherapy. The data also suggest that measuring lopinavir concentrations is not useful in predicting virologic response in these patients.

A once-daily lopinavir/ritonavir-based regimen is noninferior to twice-daily dosing and results in similar safety and tolerability in antiretroviral-naive subjects through 48 weeks.

BACKGROUND: Lopinavir/ritonavir (LPV/r)-dosed twice daily has demonstrated durable efficacy in antiretroviral-naive and protease inhibitor (PI) -experienced patients. Study M05-730 compared LPV/r tablets dosed once daily vs. twice daily in antiretroviral-naive subjects. METHODS: Six hundred sixty-four subjects were randomized to LPV/r soft gel capsules (SGCs) once daily, SGC twice daily, tablets once daily, and tablets twice daily, all with tenofovir and emtricitabine once daily. At week 8, all SGC-treated subjects were switched to tablets, maintaining randomized dose frequency. The primary efficacy analysis used an intent-to-treat, noncompleter = failure approach to assess noninferiority of the LPV/r once-daily group compared with the twice-daily group. RESULTS: At week 48, 77% of once-daily-dosed subjects vs. 76% of twice-daily-dosed subjects had HIV-1 RNA <50 copies per milliliter (P = 0.715; 95% confidence interval for difference: 5% to 8%). Response rates were numerically similar between the once-daily and twice-daily groups among subjects with baseline HIV-1 RNA > or = 100,000 copies per milliliter (75% once daily vs. 74.6% twice daily; P > 0.999) or when analyzed by baseline CD4+ T-cell count (<50, 50 to <200, and > or = 200 cells/mm3). Rates of discontinuation and adverse events, including diarrhea, were similar between arms. Among subjects with protocol-defined virologic rebound through week 48, no new PI resistance mutations were detected. CONCLUSIONS: At 48 weeks, the antiviral response in the LPV/r once-daily group was noninferior to the twice-daily group when coadministered with tenofovir and emtricitabine in antiretroviral-naive subjects. Efficacy was comparable between the once-daily and twice-daily groups regardless of baseline HIV-1 RNA or CD4+ T-cell count. Safety and tolerability of once-daily and twice-daily dosing was also comparable. No new PI resistance mutations were detected upon virologic rebound.

A 96-week comparison of lopinavir-ritonavir combination therapy followed by lopinavir-ritonavir monotherapy versus efavirenz combination therapy.

Antiretroviral-naive HIV-1-infected volunteers received zidovudine/lamivudine plus either lopinavir/ritonavir (n=104) or efavirenz (n=51). Lopinavir/ritonavir-treated subjects demonstrating 3 consecutive monthly HIV-1 RNA levels <50 copies/mL started lopinavir/ritonavir monotherapy. In previous-failure=failure analysis, 48% (lopinavir/ritonavir) and 61% (efavirenz) maintained HIV-1 RNA at <50 copies/mL through week 96, (P= .17; 95% confidence interval [CI] for the difference, -29% to 4%); in noncompletion=failure analysis, 60% (lopinavir/ritonavir) and 63% (efavirenz) maintained HIV-1 RNA at <50 copies/mL at week 96 (P= .73; 95% CI for the difference, -19% to 13%). Significant sparing of peripheral lipoatrophy was noted in the lopinavir/ritonavir simplification strategy. This study has provided important information for future studies using treatment simplified to lopinavir/ritonavir monotherapy.

Seven-year efficacy of a lopinavir/ritonavir-based regimen in antiretroviral-naïve HIV-1-infected patients.

OBJECTIVE: Evaluate efficacy and tolerability of lopinavir/ritonavir (LPV/r) plus stavudine and lamivudine long term in antiretroviral-naïve patients. DESIGN: Open-label follow-up of prospective, randomized, multicenter trial. METHOD: Antiretroviral-naïve HIV-infected subjects (N = 00) received of 3 doses of LPV/r plus stavudine and lamivudine for 48 weeks then received LPV/r soft-gel capsules 400/00 mg plus stavudine and lamivudine. After 6 years, subjects replaced stavudine with tenofovir. RESULTS: At 7 years, by intent-to-treat analysis, 61 % had plasma HIV-RNA <400 copies/mL and 59% had < 50 copies/mL. Thirty-nine subjects discontinued treatment due to adverse events (n = 6), personal/other reasons (0), loss to follow-up (9), and noncompliance (4). Among 28 subjects qualifying for drug resistance testing, no protease inhibitor or stavudine resistance was observed and 4 showed lamivudine resistance. Most common drug-related moderate or severe adverse events were diarrhea (28%), nausea (6%), and abdominal pain (11 %). Subjects who received stavudine (median 6.6 years) and switched to tenofovir demonstrated significant improvements in total cholesterol (p = .009), triglycerides (p = .023), apolipoprotein C-III (p < .001 ), adiponectin (p = .008), fasting insulin (p = .04), and leptin (p = .03). CONCLUSION: LPV/r-based therapy demonstrated sustained efficacy with no protease inhibitor or stavudine resistance through 7 years in antiretroviral-naïve patients. Switching from stavudine to tenofovir resulted in significant improvements in multiple metabolic parameters.

Evidence of ongoing immune reconstitution in subjects with sustained viral suppression following 6 years of lopinavir-ritonavir treatment.

BACKGROUND: We evaluated the immunologic impact of highly active antiretroviral therapy in subjects who maintained human immunodeficiency virus type 1 (HIV-1) suppression through 6 years of receiving a lopinavir-ritonavir-based regimen. METHODS: A total of 100 antiretroviral-naive subjects with any CD4+ T cell count initiated therapy with lopinavir-ritonavir, stavudine, and lamivudine. Sixty-three subjects who remained in the study for 6 years were assessed. Laboratory measurements included plasma HIV-1 RNA levels, multiparameter flow cytometry of immune cells, and markers of maturation and activation. RESULTS: After 6 years, 62 of 63 subjects had plasma HIV-1 RNA levels <50 copies/mL. The mean increase in CD4+ T cell count was 528 cells/microL (P<.001), and 81% of subjects had CD4+ T cell counts >500 cells/microL, compared with 21% of subjects at baseline. The mean ratio of CD4+ T cell count to CD8+ T cell count increased from 0.38 at baseline to 0.96 at year 6 (P<.001). The percentage of subjects with cell counts below the lower limit of normal at year 6, compared with at baseline, was significantly decreased for total T cells, B cells, and natural killer cells. At year 6, the median CD4+ T cell activation level was 3.4%, and the median CD8+ T cell activation level was 5.8%. CONCLUSIONS: The receipt of a lopinavir-ritonavir-based regimen resulted in ongoing immune reconstitution through 6 years of therapy in a cohort of HIV-1-infected, antiretroviral-naive subjects with suppressed HIV-1 RNA levels. Normalization of activation marker expression on CD4+ and CD8+ T cell subsets was demonstrated.

The importance of potency and durability in HIV patient antiretroviral therapy preferences: a telephone survey.

Patients who were receiving or had received antiretroviral therapy (ART) participated in 45-minute telephone interviews to evaluate the importance of major treatment attributes. A Likert scale was used to quantify and rate the importance of 9 ART attributes. Trade-off exercises allowed participants to select a preferred hypothetical ART regimen from two options based on daily dosing and varied efficacy. Participants were asked to assume that all else about the medications was the same. A total of 387 patients were surveyed (72% male; 44% African American, 41% Hispanic; 28% with no high school diploma, 29% high school graduate, 25% college with no degree; 46% infected through men who have sex with men [MSM], 19% infected through injection drug use [IDU]). Efficacy attributes (lowering viral load, raising CD4, durability) were rated as "most important" or "very important" by significantly more patients than other attributes (resistance profile, appearance side effects, gastrointestinal side effects, dosing frequency, pill burden, cholesterol side effects). Similar results were seen for subgroups analyzed by gender, ethnicity, age, line of therapy, region, and route of infection. In the second set of questions, 92% of patients preferred more effective twice-daily regimens over less effective once-daily regimens, and 89% preferred more durable twice-daily regimens over less durable once-daily regimens. Results suggest that potency, immune improvement, and durability of ART regimens are more important to HIV patients than other attributes such as side effects, dosing frequency, or pill burden. These results, in conjunction with other studies, suggest that patients prioritize viral suppression, immune improvement, and regimen durability more highly than regimen convenience.