Isabel Bravo

Gut Microbiota Linked to Sexual Preference and HIV Infection

The precise effects of HIV-1 on the gut microbiome are unclear. Initial cross-sectional studies provided contradictory associations between microbial richness and HIV serostatus and suggested shifts from Bacteroides to Prevotella predominance following HIV-1 infection, which have not been found in animal models or in studies matched for HIV-1 transmission groups. In two independent cohorts of HIV-1-infected subjects and HIV-1-negative controls in Barcelona (n = 156) and Stockholm (n = 84), men who have sex with men (MSM) predominantly belonged to the Prevotella-rich enterotype whereas most non-MSM subjects were enriched in Bacteroides, independently of HIV-1 status, and with only a limited contribution of diet effects. Moreover, MSM had a significantly richer and more diverse fecal microbiota than non-MSM individuals. After stratifying for sexual orientation, there was no solid evidence of an HIV-specific dysbiosis. However, HIV-1 infection remained consistently associated with reduced bacterial richness, the lowest bacterial richness being observed in subjects with a virological-immune discordant response to antiretroviral therapy. Our findings indicate that HIV gut microbiome studies must control for HIV risk factors and suggest interventions on gut bacterial richness as possible novel avenues to improve HIV-1-associated immune dysfunction.

The Lipid-Lowering Effect of Tenofovir/Emtricitabine: A Randomized, Crossover, Double-Blind, Placebo-Controlled Trial

BACKGROUND It is unknown if tenofovir disoproxil fumarate (TDF), which is often coformulated with the lipid-neutral emtricitabine (FTC), has a lipid-lowering effect. METHODS We performed a randomized, crossover, double-blind, placebo-controlled clinical trial on human immunodeficiency virus type 1 (HIV-1)-infected subjects with HIV-1 RNA < 50 copies/mL during ≥6 months on stable darunavir/ritonavir (800/100 mg once daily) or lopinavir/ritonavir (400/100 mg twice daily) monotherapy, fasting total cholesterol (TC) ≥200 mg/dL or low-density lipoprotein cholesterol (LDL-c) ≥130 mg/dL, and no lipid-lowering drugs. In arm 1, TDF/FTC was added for 12 weeks, followed by 12 weeks of placebo (washout) and 12 additional weeks of placebo (placebo period). Subjects in arm 2 added placebo for 12 weeks (placebo period) followed by TDF/FTC for 12 weeks and placebo for 12 additional weeks (washout). The primary endpoint was change in median fasting TC levels. RESULTS Of 46 subjects enrolled, 56% received darunavir/ritonavir and 44% lopinavir/ritonavir. Exposure to TDF/FTC reduced TC from 234 to 205 mg/dL (P < .001), LDL-c from 155 to 128 mg/dL (P < .001), and high-density lipoprotein cholesterol (HDL-c) from 50.3 to 44.5 mg/dL (P < .001). It also decreased the proportion of subjects with fasting TC ≥200 mg/dL from 86.7% to 56.8% (P = .001), and LDL-c ≥130 mg/dL from 87.8% to 43.9% (P < .001). After 12 weeks, TDF/FTC exposure was associated with lower TC and LDL-c levels than placebo (P = .001 and P = .002, respectively). The TC/HDL-c ratio and triglyceride levels did not change with TDF/FTC exposure. CONCLUSIONS Coformulated TDF/FTC has an intrinsic lipid-lowering effect, likely attributable to TDF. CLINICAL TRIALS REGISTRATION NCT01458977.

Virological Efficacy in Cerebrospinal Fluid and Neurocognitive Status in Patients with Long-Term Monotherapy Based on Lopinavir/Ritonavir: An Exploratory Study

Background Data on suppression of HIV replication in the CNS and on the subsequent risk of neurocognitive impairment using monotherapy with boosted protease inhibitors are limited. Methods Ours was an exploratory cross-sectional study in patients on lopinavir/ritonavir-based monotherapy (LPV/r-MT) or standard triple therapy (LPV/r-ART) for at least 96 weeks who maintained a plasma viral load <50 copies/mL. HIV-1 RNA in CSF was determined by HIV-1 SuperLow assay (lower limit of detection, 1 copy/mL). Neurocognitive functioning was assessed using a recommended battery of neuropsychological tests covering 7 areas. Neurocognitive impairment (NCI) was determined and also a global deficit score (GDS) for study comparisons. Results Seventeen patients on LPV/r-MT and 17 on LPV/r-ART were included. Fourteen (82.4%) patients on LPV/r-MT and 16 (94.1%) on LPV/r-ART had HIV-1 RNA <1 copy/mL in CSF (p = 0.601). NCI was observed in 7 patients on LPV/r-MT and in 10 on LPV/r-ART (41% vs 59%; p = 0.494). Mean (SD) GDS was 0.22 (0.20) in patients on LPV/r-MT and 0.47 (0.34) in those on LPV/r-ART (p = 0.012). Conclusions Suppression of HIV in CSF is similar in individuals with durable plasma HIV-1 RNA suppression who are receiving LPV/r-MT or LPV/r-ART for at least 96 weeks. Findings for HIV-1 replication in CSF and neurocognitive status indicate that this strategy seems to be safe for CNS functioning.

Antiretroviral simplification with darunavir/ritonavir monotherapy in routine clinical practice: safety, effectiveness, and impact on lipid profile.

Background Simplification of antiretroviral treatment (ART) with darunavir/ritonavir (DRV/r) monotherapy has achieved sustained suppression of plasma viral load (pVL) in clinical trials; however, its effectiveness and safety profile has not been evaluated in routine clinical practice. Methodology/Principal Findings We performed a retrospective cohort analysis of HIV-1-infected patients who initiated DRV/r monotherapy once daily with a pVL <50 copies/mL under ART and at least 1 subsequent follow-up visit in our clinic. The primary study endpoints were the percentage of patients with virological failure (VF, defined as 2 consecutive pVL>50 copies/mL) at week 48, and time to VF. Other causes of treatment discontinuation and changes in lipid profile were evaluated up to week 48. Ninety-two patients were followed for a median (IQR) of 73 (57–92) weeks. The median baseline and nadir CD4+ T-cell counts were 604 (433–837) and 238 (150–376) cells/mm3, respectively. Patients had previously received a median of 5 (3–9) ART lines and maintained a pVL<50 copies/mL for a median of 76 (32–176) weeks before initiating DRV/r monotherapy. Nine (9.8%) patients developed VF at week 48; time to VF was 47.1 (IQR: 36.1–47.8) weeks among patients with VF. Other reasons for changing ART were gastrointestinal disturbances (n = 3), rash (n = 1), and impaired CD4 recovery (n = 2). Median low-density lipoprotein cholesterol levels increased from 116.1 mg/dL at baseline to 137.3 mg/dL at 48 weeks (p = 0.001). Conclusions/Significance Treatment simplification with DRV/r monotherapy seems safe and effective in routine clinical practice. Further research is needed to elucidate the effect of DRV/r monotherapy on cholesterol levels.

Efficacy and safety of nucleoside reverse transcriptase inhibitor-sparing salvage therapy for multidrug-resistant HIV-1 infection based on new-class and new-generation antiretrovirals

BACKGROUND The advent of new antiretrovirals has expanded the therapeutic options for multiple drug-resistant HIV-1 infection. The role of recycled nucleoside reverse transcriptase inhibitors (NRTIs) in this scenario remains uncertain. METHODS Observational study of 122 consecutive patients with prior triple-class failure and multidrug-resistant HIV infection who started a salvage regimen with at least three of the new antiretrovirals darunavir, etravirine, raltegravir and maraviroc. Virological, immunological and clinical outcomes were compared according to the inclusion or not of NRTIs in the regimen, after 48 weeks of follow-up. RESULTS All patients received at least two and 65% received three fully active drugs in the salvage regimen. In 63 patients recycled NRTIs were added to new drugs (NRTI-containing group) and 59 patients did not receive NRTIs (NRTI-sparing group). Both groups were comparable at baseline regarding the number of prior failures, resistance profile, CD4 cell count and HIV plasma viral load. The rates of HIV-1 RNA suppression below 50 copies/mL at week 48 (intent-to-treat analysis) were similar in the two groups: 46/59 [78%, 95% confidence interval (CI) 67%-88%] in the NRTI-sparing group and 49/63 (78%, 95% CI 67%-88%) in the NRTI-containing group. No significant differences were found in CD4 cell count increases. Drug-related adverse events leading to drug discontinuations only occurred in the NRTI-containing group (5 of 63, NRTI-related in 3 cases). CONCLUSIONS The addition of NRTIs with reduced activity, according to genotypic resistance tests, does not seem to improve the efficacy of salvage regimens containing three of the new antiretrovirals in patients with multidrug-resistant HIV-1 infection.

The Hidden Sexuality of Alexandrium Minutum: An Example of Overlooked Sex in Dinoflagellates.

Dinoflagellates are haploid eukaryotic microalgae in which rapid proliferation causes dense blooms, with harmful health and economic effects to humans. The proliferation mode is mainly asexual, as the sexual cycle is believed to be rare and restricted to stressful environmental conditions. However, sexuality is key to explaining the recurrence of many dinoflagellate blooms because in many species the fate of the planktonic zygotes (planozygotes) is the formation of resistant cysts in the seabed (encystment). Nevertheless, recent research has shown that individually isolated planozygotes in the lab can enter other routes besides encystment, a behavior of which the relevance has not been explored at the population level. In this study, using imaging flow cytometry, cell sorting, and Fluorescence In Situ Hybridization (FISH), we followed DNA content and nuclear changes in a population of the toxic dinoflagellate Alexandrium minutum that was induced to encystment. Our results first show that planozygotes behave like a population with an “encystment-independent” division cycle, which is light-controlled and follows the same Light:Dark (L:D) pattern as the cycle governing the haploid mitosis. Resting cyst formation was the fate of just a small fraction of the planozygotes formed and was restricted to a period of strongly limited nutrient conditions. The diploid-haploid turnover between L:D cycles was consistent with two-step meiosis. However, the diel and morphological division pattern of the planozygote division also suggests mitosis, which would imply that this species is not haplontic, as previously considered, but biphasic, because individuals could undergo mitotic divisions in both the sexual (diploid) and the asexual (haploid) phases. We also report incomplete genome duplication processes. Our work calls for a reconsideration of the dogma of rare sex in dinoflagellates.

Monotherapy with boosted PIs as an ART simplification strategy in clinical practice

BACKGROUND Data on the efficacy of simplifying therapy using darunavir/ritonavir and lopinavir/ritonavir monotherapy in clinical practice remain limited. METHODS A retrospective single-centre study including patients initiating darunavir/ritonavir or lopinavir/ritonavir monotherapy with a plasma HIV-1 viral load (pVL) <50 copies/mL and at least one subsequent follow-up visit. The primary endpoint was the percentage of patients remaining free of virological failure (VF; defined as a confirmed pVL >50 copies/mL or as any change in the regimen after a single determination with a pVL >50 copies/mL) during the follow-up. We also evaluated the percentage of patients remaining free of treatment failure (TF; defined as VF or the early discontinuation of monotherapy for any reason) and compared the effectiveness of the two regimens. Effectiveness was evaluated using cumulative survival analysis (at Weeks 48 and 96). Factors associated with VF and TF were analysed using Cox regression. RESULTS A total of 522 patients were included (309 receiving lopinavir/ritonavir and 213 receiving darunavir/ritonavir). The median follow-up was 64.3 (30.5-143.0) weeks. The percentage of patients free of VF and TF was 94% (95% CI 91%-96%) and 79% (95% CI 75%-82%) at 48 weeks, respectively, and 86% (95% CI 81%-89%) and 62% (95% CI 57%-67%) at 96 weeks, respectively. The risk of VF was similar for the two regimens (HR=1.0, 95% CI 0.6-1.8; P=0.962). Lopinavir/ritonavir monotherapy was associated with a 1.5-fold greater risk of TF (95% CI 1.1-2.1; P=0.012) and a 2.3-fold greater risk of discontinuation of therapy due to adverse events (95% CI 1.3-3.9; P=0.003). CONCLUSIONS The virological efficacy of darunavir/ritonavir and lopinavir/ritonavir monotherapy is high in clinical practice. Treatment discontinuation due to safety issues is more frequent with lopinavir/ritonavir.

A Kinetic and Factorial Approach to Study the Effects of Temperature and Salinity on Growth and Toxin Production by the Dinoflagellate Alexandrium ostenfeldii from the Baltic Sea

Alexandrium ostenfeldii is present in a wide variety of environments in coastal areas worldwide and is the only dinoflagellate known species that produces paralytic shellfish poisoning (PSP) toxins and two types of cyclic imines, spirolides (SPXs) and gymnodimines (GYMs). The increasing frequency of A. ostenfeldii blooms in the Baltic Sea has been attributed to the warming water in this region. To learn more about the optimal environmental conditions favoring the proliferation of A. ostenfeldii and its complex toxicity, the effects of temperature and salinity on the kinetics of both the growth and the net toxin production of this species were examined using a factorial design and a response-surface analysis (RSA). The results showed that the growth of Baltic A. ostenfeldii occurs over a wide range of temperatures and salinities (12.5–25.5°C and 5–21, respectively), with optimal growth conditions achieved at a temperature of 25.5°C and a salinity of 11.2. Together with the finding that a salinity > 21 was the only growth-limiting factor detected for this strain, this study provides important insights into the autecology and population distribution of this species in the Baltic Sea. The presence of PSP toxins, including gonyautoxin (GTX)-3, GTX-2, and saxitoxin (STX), and GYMs (GYM-A and GYM-B/-C analogues) was detected under all temperature and salinity conditions tested and in the majority of the cases was concomitant with both the exponential growth and stationary phases of the dinoflagellate’s growth cycle. Toxin concentrations were maximal at temperatures and salinities of 20.9°C and 17 for the GYM-A analogue and > 19°C and 15 for PSP toxins, respectively. The ecological implications of the optimal conditions for growth and toxin production of A. ostenfeldii in the Baltic Sea are discussed.

Short Communication: Efficacy and Safety of Treatment Simplification to Lopinavir/Ritonavir or Darunavir/Ritonavir Monotherapy: A Randomized Clinical Trial.

Abstract Antiretroviral treatment simplification strategies based on monotherapy with darunavir/ritonavir (DRV/r) or lopinavir/ritonavir (LPV/r) have not been directly compared in clinical trials. We evaluated the 48-week efficacy and safety of DRV/r versus LPV/r monotherapy as a treatment simplification strategy in a multicenter, randomized open-label study. Maintenance of viral suppression in cerebrospinal fluid (CSF) and semen was also explored. An intention to treat efficacy analysis was performed considering missing equals to failure (ITT:M = F). Virological failure (VF) was defined as a confirmed increase in plasma HIV-1 RNA >50 copies/mL. A total of 75 patients were enrolled: 40 were allocated to DRVr and 33 to LPVr. In the ITT: M = F analysis, 77.5% of patients on DRV/r and 66.6% of patients on LPV/r maintained HIV-1 RNA <50 copies/mL at week 48 (p = .302, treatment difference 10.8% [95% CI,–12.6 to 34.2]). In the DRV/r arm, no patients developed VF and 15.0% discontinued treatment due to adverse ...Antiretroviral treatment simplification strategies based on monotherapy with darunavir/ritonavir (DRV/r) or lopinavir/ritonavir (LPV/r) have not been directly compared in clinical trials. We evaluated the 48-week efficacy and safety of DRV/r versus LPV/r monotherapy as a treatment simplification strategy in a multicenter, randomized open-label study. Maintenance of viral suppression in cerebrospinal fluid (CSF) and semen was also explored. An intention to treat efficacy analysis was performed considering missing equals to failure (ITT:M = F). Virological failure (VF) was defined as a confirmed increase in plasma HIV-1 RNA >50 copies/mL. A total of 75 patients were enrolled: 40 were allocated to DRVr and 33 to LPVr. In the ITT: M = F analysis, 77.5% of patients on DRV/r and 66.6% of patients on LPV/r maintained HIV-1 RNA <50 copies/mL at week 48 (p = .302, treatment difference 10.8% [95% CI,-12.6 to 34.2]). In the DRV/r arm, no patients developed VF and 15.0% discontinued treatment due to adverse events. In the LPV/r arm, 2 (6.1%) patients developed VF and 18.2% discontinued monotherapy due to adverse events. Gastrointestinal disturbances were experienced by 18.2% and 2.5% of patients in the LPV/r and DRV/r arms, respectively (p = .019). Two patients had detectable HIV-1 RNA ≥50 copies/mL in CSF or semen. Monotherapy with LPV/r or DRV/r seems to be virologically effective in selected HIV-1-infected patients with sustained viral suppression. Differences between both regimens seem driven mainly by the better tolerability profile of DRV/r.

“Canary Islands (NE Atlantic) as a biodiversity ‘hotspot’ of Gambierdiscus: Implications for future trends of ciguatera in the area”

In the present study the geographical distribution, abundance and composition of Gambierdiscus was described over a 600km longitudinal scale in the Canary Islands. Samples for cell counts, isolation and identification of Gambierdiscus were obtained from five islands (El Hierro, Tenerife, Gran Canaria, Fuerteventura and Lanzarote). Average densities of Gambierdiscus spp. between 0 and 2200cellsg-1 blot dry weight of macrophyte were recorded. Morphological (light microscopy and SEM techniques) and molecular analyses (LSU and SSU rDNA sequencing of cultures and single cells from the field) of Gambierdiscus was performed. Five Gambierdiscus species (G. australes, G. caribaeus, G. carolinianus, G. excentricus and G. silvae), together with a new putative species (Gambierdiscus ribotype 3) were identified. These results suggest that some cases of CFP in the region could be associated with the accumulation of ciguatoxins in the marine food web acquired from local populations of Gambierdiscus. This unexpected high diversity of Gambierdiscus species in an area which a priori is not under risk of ciguatera, hints at an ancient settlement of Gambierdiscus populations, likely favored by warmer climate conditions in the Miocene Epoch (when oldest current Canary Islands were created), in contrast with cooler present ones. Currently, warming trends associated with climate change could contribute to extend favorable environmental conditions in the area for Gambierdiscus growth especially during winter months.