Integrated Delivery of Antiretroviral Treatment and Pre-exposure Prophylaxis to HIV-1–Serodiscordant Couples: A Prospective Implementation Study in Kenya and Uganda

BackgroundAntiretroviral-based interventions for HIV-1 prevention, including antiretroviral therapy (ART) to reduce the infectiousness of HIV-1 infected persons and pre-exposure prophylaxis (PrEP) to reduce the susceptibility of HIV-1 uninfected persons, showed high efficacy for HIV-1 protection in randomized clinical trials. We conducted a prospective implementation study to understand the feasibility and effectiveness of these interventions in delivery settings.ConclusionsIntegrated delivery of time-limited PrEP until sustained ART use in African HIV-1-serodiscordant couples was feasible, demonstrated high uptake and adherence, and resulted in near elimination of HIV-1 transmission, with an observed HIV incidence of <0.5% per year compared to an expected incidence of >5% per year.     

Factors associated with HIV infection in married or cohabitating couples in Kenya: results from a nationally representative study

Background

In order to inform prevention programming, we analyzed HIV discordance and concordance within couples in the Kenya AIDS Indicator Survey (KAIS) 2007.

Methods

KAIS was a nationally representative population-based sero-survey that examined demographic and behavioral indicators and serologic testing for HIV, HSV-2, syphilis, and CD4 cell counts in 15,853 consenting adults aged 15–64 years. We analyzed interview and blood testing data at the sexual partnership level from married or cohabitating couples. Multivariable regression models were used to identify factors independently associated with HIV discordant and concordant status.

Results

Of 3256 couples identified in the survey, 2748 (84.4%) had interview and blood testing data. Overall, 3.8% of couples were concordantly infected with HIV, and in 5.8% one partner was infected, translating to 338,000 discordant couples in Kenya. In 83.6% of HIV-infected Kenyans living in married or cohabitating couples neither partner knew their HIV status. Factors independently associated with HIV-discordance included young age in women (AOR 1.5, 95% CI: 1.2–1.8; p<0.0001), increasing number of lifetime sexual partners in women (AOR 1.5, 95% CI: 1.3–1.8; p<0.0001), HSV-2 infection in either or both partners (AOR 4.1, 95% CI: 2.3–7.2; p<0.0001), and lack of male circumcision (AOR 1.6, 95% CI: 1.0–2.5; p = 0.032). Independent factors for HIV-concordance included HSV-2 infection in both partners (AOR 6.5, 95% CI: 2.3–18.7; p = 0.001) and lack of male circumcision (AOR 1.8, 95% CI: 1.0–3.3; p = 0.043).

Conclusions

Couple prevention interventions should begin early in relationships and include mutual knowledge of HIV status, reduction of outside sexual partners, and promotion of male circumcision among HIV-uninfected men. Mechanisms for effective prevention or suppression of HSV-2 infection are also needed.     

The effect of sodium bicarbonate on a single dose of diethylcarbamazine therapy in patients with bancroftian filariasis in Kenya

An attempt was made to examine the effect of a combination of diethylcarbamazine citrate (DEC-C) and sodium bicarbonate (NaHCO₃) on the pharmacokinetics of diethylcarbamazine (DEC), side-reactions and reduction of the microfilarial density of patients with Wuchereria bancrofti infection at a hospital in Nairobi, Kenya. The microfilariae carriers received DEC-C at 6 mg/kg or 3 mg/kg with or without NaHCO₃ at 75 mg/kg body weight. The patients treated with a combination of drugs showed alkaline urine for 4 h post-treatment, while patients treated with DEC-C alone showed acidic urine. Although no significant difference was detected in the DEC half-life value and other pharmacokinetic parameters between patients treated with DEC-C (6 mg/kg) plus NaHCO₃ (75 mg/kg) and those treated with DEC-C (6 mg/kg) alone, the general tendency was that in patients receiving NaHCO₃ the first-order elimination rate constant decreased and serum elimination half-life and area under the serum concentration-time curve values increased. There was a significant difference between the mean values of the first-order absorption rate constant, the first-order elimination rate constant, and the time to maximum serum concentrations for the patients receiving DEC-C at 3 mg/kg plus NaHCO₃ at 75 mg/kg and those for the group receiving DEC-C at 6 mg/kg alone. There was no difference in frequency and severity of the side-reactions between patients receiving DEC-C at 6 mg/kg plus NaHCO₃ at 75 mg/kg, DEC-C at 3 mg/kg plus NaHCO₃ at 75 mg/kg, and DEC-C at 6 mg/kg alone. During the initial 5 days post-treatment, there was no significant difference in reduction of microfilarial density among these three groups. In the field, an attempt was made to examine the possibility of increased antifilarial effect using a combination of DEC-C and NaHCO₃. The patients were examined for microfilariae, given DEC-C at 6 mg/kg with or without NaHCO₃ at 75 mg/kg, and examined for microfilariae again 1 year later. Although the cure rate was the same among the groups, the percentage reduction in microfilarial density of the patients receiving DEC-C plus NaHCO₃ was significantly greater than those of patients receiving DEC-C alone. A combination of DEC-C with NaHCO₃ will be of practical value in a single dose of DEC-C for the mass-treatment of bancroftian filariasis.     

Delipidation of mammalian Atg8-family proteins by each of the four ATG4 proteases

During macroautophagy/autophagy, mammalian Atg8-family proteins undergo 2 proteolytic processing events. The first exposes a COOH-terminal glycine used in the conjugation of these proteins to lipids on the phagophore, the precursor to the autophagosome, whereas the second releases the lipid. The ATG4 family of proteases drives both cleavages, but how ATG4 proteins distinguish between soluble and lipid-anchored Atg8 proteins is not well understood. In a fully reconstituted delipidation assay, we establish that the physical anchoring of mammalian Atg8-family proteins in the membrane dramatically shifts the way ATG4 proteases recognize these substrates. Thus, while ATG4B is orders of magnitude faster at processing a soluble unprimed protein, all 4 ATG4 proteases can be activated to similar enzymatic activities on lipid-attached substrates. The recognition of lipidated but not soluble substrates is sensitive to a COOH-terminal LIR motif both in vitro and in cells. We suggest a model whereby ATG4B drives very fast priming of mammalian Atg8 proteins, whereas delipidation is inherently slow and regulated by all ATG4 homologs.     

A Scoring Tool to Identify East African HIV-1 Serodiscordant Partnerships with a High Likelihood of Pregnancy

Introduction

HIV-1 prevention programs targeting HIV-1 serodiscordant couples need to identify couples that are likely to become pregnant to facilitate discussions about methods to minimize HIV-1 risk during pregnancy attempts (i.e. safer conception) or effective contraception when pregnancy is unintended. A clinical prediction tool could be used to identify HIV-1 serodiscordant couples with a high likelihood of pregnancy within one year.

Methods

Using standardized clinical prediction methods, we developed and validated a tool to identify heterosexual East African HIV-1 serodiscordant couples with an increased likelihood of becoming pregnant in the next year. Datasets were from three prospectively followed cohorts, including nearly 7,000 couples from Kenya and Uganda participating in HIV-1 prevention trials and delivery projects.

Results

The final score encompassed the age of the woman, woman’s number of children living, partnership duration, having had condomless sex in the past month, and non-use of an effective contraceptive. The area under the curve (AUC) for the probability of the score to correctly predict pregnancy was 0.74 (95% CI 0.72–0.76). Scores ≥7 predicted a pregnancy incidence of >17% per year and captured 78% of the pregnancies. Internal and external validation confirmed the predictive ability of the score.

Discussion

A pregnancy likelihood score encompassing basic demographic, clinical and behavioral factors defined African HIV-1 serodiscordant couples with high one-year pregnancy incidence rates. This tool could be used to engage African HIV-1 serodiscordant couples in counseling discussions about fertility intentions in order to offer services for safer conception or contraception that align with their reproductive goals.     

Focus on Metabolism: Glutathionylation and Reduction of Methacrolein in Tomato Plants Account for Its Absorption from the Vapor Phase

A large portion of the volatile organic compounds emitted by plants are oxygenated to yield reactive carbonyl species, which have a big impact on atmospheric chemistry. Deposition to vegetation driven by the absorption of reactive carbonyl species into plants plays a major role in cleansing the atmosphere, but the mechanisms supporting this absorption have been little examined. Here, we performed model experiments using methacrolein (MACR), one of the major reactive carbonyl species formed from isoprene, and tomato (Solanum lycopersicum) plants. Tomato shoots enclosed in a jar with MACR vapor efficiently absorbed MACR. The absorption efficiency was much higher than expected from the gas/liquid partition coefficient of MACR, indicating that MACR was likely metabolized in leaf tissues. Isobutyraldehyde, isobutyl alcohol, and methallyl alcohol (MAA) were detected in the headspace and inside tomato tissues treated with MACR vapor, suggesting that MACR was enzymatically reduced. Glutathione (GSH) conjugates of MACR (MACR-GSH) and MAA (MAA-GSH) were also detected. MACR-GSH was essentially formed through spontaneous conjugation between endogenous GSH and exogenous MACR, and reduction of MACR-GSH to MAA-GSH was likely catalyzed by an NADPH-dependent enzyme in tomato leaves. Glutathionylation was the metabolic pathway most responsible for the absorption of MACR, but when the amount of MACR exceeded the available GSH, MACR that accumulated reduced photosynthetic capacity. In an experiment simulating the natural environment using gas flow, MACR-GSH and MAA-GSH accumulation accounted for 30% to 40% of the MACR supplied. These results suggest that MACR metabolism, especially spontaneous glutathionylation, is an essential factor supporting MACR absorption from the atmosphere by tomato plants.Plants emit vast amounts of volatile organic chemicals (VOCs) into the atmosphere. The annual emission of VOCs other than methane is estimated to be approximately 1,300 Tg of carbon (Goldstein and Galbally, 2007), with approximately 90% originating from biogenic sources, of which one-third (approximately 500 Tg of carbon/year) is isoprene (Guenther et al., 1995). In the atmosphere, VOCs undergo the chemical processes of photolysis and reaction with hydroxyl and nitrate radicals (Atkinson and Arey, 2003). Isoprene, for example, is converted into a series of isomeric hydroxyl-substituted alkyl peroxyl radicals, which are further converted into methyl vinyl ketone (MVK; but-3-en-2-one) and methacrolein (MACR; 2-methylprop-2-enal; Liu et al., 2013). These VOCs and their oxygenated products (oVOCs) are important components for the production of ozone and aerosols, and thus have a big impact on atmospheric chemistry and even on the climate system (Goldstein and Galbally, 2007). VOCs and oVOCs are removed from the atmosphere through oxidation to carbon monoxide or dioxide, dry or wet deposition, or secondary aerosol formation (Goldstein and Galbally, 2007). Among these, deposition to vegetation plays a major role in the removal of VOCs and oVOCs from the atmosphere (Karl et al., 2010).A significant portion of the deposition to vegetation is attributable to the uptake of VOCs and oVOCs by plants, and a field study showed that MVK and MACR were immediately lost once they entered a leaf through stomata (Karl et al., 2010). Under growth conditions where stomatal conductance is high enough, the partitioning of VOCs between air and leaf water phases in equilibrium and the capacity of the plant to metabolize, translocate, and store VOCs determine their uptake rate (Tani et al., 2013). The immediate loss in leaves observed with MVK and MACR is indicative of efficient enzymatic reactions metabolizing them; however, the details of the metabolism of these oVOCs have been little investigated so far.The absorption and metabolism of several VOCs by plants have been reported. Airborne ent-kaurene was absorbed by Arabidopsis (Arabidopsis thaliana), Japanese cypress (Chamaecyparis obtusa), and Japanese cedar (Cryptomeria japonica) plants and converted into GAs (Otsuka et al., 2004). Arabidopsis absorbed (Z)-3-hexenal and converted it into (Z)-3-hexen-1-ol or further into (Z)-3-hexen-1-yl acetate using NADPH and acetyl-CoA, probably inside the plant tissues (Matsui et al., 2012). Nicotiana attenuata plants absorbed dimethyl disulfide formed by rhizobacteria (Meldau et al., 2013). The sulfur atom derived from volatile dimethyl disulfide was assimilated into plant proteins. Karl et al. (2010) assumed that aldehyde dehydrogenase, which is involved in detoxification that limits aldehyde accumulation and oxidative stress (Kirch et al., 2004), is involved in the uptake of oVOCs containing an aldehyde moiety; however, they did not provide direct evidence supporting their assumption.Conjugation of VOCs and oVOCs with sugar or glutathione (GSH) is another way to metabolize them. (Z)-3-Hexen-1-ol in the vapor phase was taken up by tomato (Solanum lycopersicum) plants and converted into its glycoside (Sugimoto et al., 2014). (E)-2-Hexenal reacts with GSH spontaneously and/or via glutathione S-transferase (GST) to form hexanal-GSH, which is subsequently reduced to hexanol-GSH (Davoine et al., 2006), although it is uncertain whether airborne (E)-2-hexenal is converted into its corresponding GSH adduct. Glutathionylation of (E)-2-hexenal is common and has been confirmed in grapevine (Vitis vinifera) and passion fruit (Passiflora edulis; Kobayashi et al., 2011; Fedrizzi et al., 2012). The catabolites formed from the GSH adduct in these crops are precursors for important flavor components.Although it is clear that oVOCs are absorbed by vegetation and that their efficient uptake is probably supported by metabolism in plant tissues, the metabolic fates of oVOCs taken up from the vapor phase into plants have been little studied. Here, we performed a series of model experiments using tomato seedlings and MACR to dissect the fates of oVOCs once they entered into plant tissues. To clearly see absorption of MACR and its fates in plant tissues, a model experiment under enclosed conditions with a high concentration of MACR was first carried out. Subsequently, an airflow system with a realistically low concentration of MACR was used. Tomato plants efficiently absorbed MACR. Reduction of the carbonyl moiety and the double bond conjugated to the carbonyl and conjugation with GSH were the major methods of metabolism of exogenous MACR. The metabolism seemed to be involved in the detoxification of reactive carbonyl species, which, in turn, accounted for the oVOC deposition to vegetation.     

Safety and adherence to intermittent pre-exposure prophylaxis (PrEP) for HIV-1 in African men who have sex with men and female sex workers

Background

Little is known about safety of and adherence to intermittent HIV PrEP regimens, which may be more feasible than daily dosing in some settings. We present safety and adherence data from the first trial of an intermittent PrEP regimen among Kenyan men who have sex with men (MSM) and female sex workers (FSW).

Methods/Principal Findings

MSM and FSW were randomized to daily oral FTC/TDF or placebo, or intermittent (Monday, Friday and within 2 hours after sex, not to exceed one dose per day) oral FTC/TDF or placebo in a 2∶1∶2∶1 ratio; volunteers were followed monthly for 4 months. Adherence was assessed with the medication event monitoring system (MEMS). Sexual activity data were collected via daily text message (SMS) queries and timeline followback interviews with a one-month recall period. Sixty-seven men and 5 women were randomized into the study. Safety was similar among all groups. Median MEMS adherence rates were 83% [IQR: 63–92] for daily dosing and 55% [IQR:28–78] for fixed intermittent dosing (p = 0.003), while adherence to any post-coital doses was 26% [IQR:14–50]. SMS response rates were low, which may have impaired measurement of post-coital dosing adherence. Acceptability of PrEP was high, regardless of dosing regimen.

Conclusions/Significance

Adherence to intermittent dosing regimens, fixed doses, and in particular coitally-dependent doses, may be more difficult than adherence to daily dosing. However, intermittent dosing may still be appropriate for PrEP if intracellular drug levels, which correlate with prevention of HIV acquisition, can be attained with less than daily dosing and if barriers to adherence can be addressed. Additional drug level data, qualitative data on adherence barriers, and better methods to measure sexual activity are necessary to determine whether adherence to post-coital PrEP could be comparable to more standard regimens.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00971230","term_id":"NCT00971230"}}NCT00971230     

Regulation of phenylacetic acid degradation genes of Burkholderia cenocepacia K56-2

Background  

Metabolically versatile soil bacteria Burkholderia cepacia complex (Bcc) have emerged as opportunistic pathogens, especially of cystic fibrosis (CF). Previously, we initiated the characterization of the phenylacetic acid (PA) degradation pathway in B. cenocepacia, a member of the Bcc, and demonstrated the necessity of a functional PA catabolic pathway for full virulence in Caenorhabditis elegans. In this study, we aimed to characterize regulatory elements and nutritional requirements that control the PA catabolic genes in B. cenocepacia K56-2.     

Pre-exposure Prophylaxis Use by Breastfeeding HIV-Uninfected Women: A Prospective Short-Term Study of Antiretroviral Excretion in Breast Milk and Infant Absorption

BackgroundAs pre-exposure prophylaxis (PrEP) becomes more widely used in heterosexual populations, an important consideration is its safety in infants who are breastfed by women taking PrEP. We investigated whether tenofovir and emtricitabine are excreted into breast milk and then absorbed by the breastfeeding infant in clinically significant concentrations when used as PrEP by lactating women.ConclusionIn this short-term study of daily directly observed oral PrEP in HIV-uninfected breastfeeding women, the estimated infant doses from breast milk and resultant infant plasma concentrations for tenofovir and emtricitabine were 12,500 and >200-fold lower than the respective proposed infant therapeutic doses, and tenofovir was not detected in 94% of infant plasma samples. These data suggest that PrEP can be safely used during breastfeeding with minimal infant drug exposure.

Trial Registration

ClinicalTrials.gov, Identifier: {"type":"clinical-trial","attrs":{"text":"NCT02776748","term_id":"NCT02776748"}}NCT02776748