John C. Forbes

Lactic acidemia in human immunodeficiency virus-uninfected infants exposed to perinatal antiretroviral therapy

Objective. To investigate potential mitochondrial toxicity in HIV-uninfected infants exposed to highly active antiretroviral therapy (HAART) in utero and/or neonatal zidovudine. Design. A prospective observational study performed in a tertiary referral center for HIV-infected women and their infants and children. Methods. Plasma lactate was measured repeatedly during the first 6 months of life in a consecutive cohort of infants exposed to HAART in utero and/or neonatal zidovudine. Maternal CD4, HIV RNA concentration, antiretroviral and substance use histories, mode of delivery, infant gender, cord pH, Apgar score and birth weight were collected. Results. The plasma lactate was above normal on at least 1 occasion in 35 of 38 (92%) infants and reached levels ≥5 mmol/l in 10 (26%) infants. Overall 78 of 117 (68%) lactate measurements were elevated, with 11 (10%) in the serious (≥5 mmol/l) range. None of the infants received antiretrovirals beyond 6 weeks, yet elevated lactates persisted up to age 6 months. Two infants had reversible symptoms consistent with those of lactic acidemia. No association was found between the infant peak lactate and the type of therapy during pregnancy, its duration or maternal substance use. Conclusion. Transient lactic acidemia was observed in the majority of HIV uninfected infants exposed to HAART in utero and/or zidovudine neonatally. We hypothesize that the hyperlactatemia is a consequence of persistent, primarily subclinical, mitochondrial toxicity from the transplacental and neonatal exposure to antiretrovirals and of impaired hepatic lactate clearance. Although the clinical relevance of our findings is unknown, we recommend lactate monitoring in these infants, considering discontinuation of neonatal zidovudine in symptomatic infants with lactate ≥5 mmol/l and careful long term follow up of these children.

A national review of vertical HIV transmission

Objectives:Prevention of vertical HIV transmission has evolved significantly in Canada over the last two decades. The aim of this analysis is to describe the surveillance programme used, rate of vertical HIV transmission and changing epidemiology of HIV-affected pregnancies in Canada. Design:National perinatal HIV surveillance programme. Methods:From 1990, annual retrospective data was collected on demographic and clinical characteristics of HIV-infected mothers and their infants referred to 22 participating sites across Canada either before/during pregnancy or within 3 months after delivery. Factors impacting HIV transmission and demographic features were explored. Results:Two thousand, six hundred and ninety-two mother–infant pairs were identified. The overall rate of vertical HIV transmission was 5.2%, declining to 2.9% since 1997. The rate of transmission for mothers who received HAART was 1%, and 0.4% if more than 4 weeks of HAART was given. Forty percent of women delivered by caesarean section, with no difference in transmission rate compared with vaginal delivery for women treated with HAART (1.4 vs. 0.6%, P = 0.129) but significant risk reduction for those who did not receive HAART (3.8 vs. 10.3%, P = 0.016). Black women were the largest group; proportions of black and aboriginal women increased significantly over time (P < 0.001 for both). Heterosexual contact was the most common risk category for maternal infection (65%), followed by injection drug use (IDU) (25%). Conclusion:Vertical HIV transmission in Canada has decreased dramatically for women treated with HAART therapy. All pregnant women should be evaluated for HIV infection and programmes expanded to reach vulnerable populations including aboriginal, immigrant and IDU women.

A Prospective Controlled Study of Neurodevelopment in HIV-Uninfected Children Exposed to Combination Antiretroviral Drugs in Pregnancy

OBJECTIVE. Our intent was to investigate the neurodevelopment of HIV-uninfected children exposed to combination highly active antiretroviral therapy in pregnancy compared with children not exposed to highly active antiretroviral therapy but with similar socioeconomic backgrounds. PATIENTS AND METHODS. A prospective controlled cross-sectional study of the neurodevelopment of children exposed to highly active antiretroviral therapy versus those not exposed was performed by using the Bayley Scales of Infant Development and Vineland Adaptive Behavior Scales at 18 to 36 months of age. The highly active antiretroviral therapy–exposed children were born to HIV-infected women but were uninfected themselves. The control children were born to HIV-uninfected women with similar anticipated socioeconomic background (hepatitis C infected and high proportion of substance use). Sociodemographic, clinical, highly active antiretroviral therapy (antenatal, intrapartum, neonatal), and substance-use histories were collected. Results were compared by using analyses of covariance and χ2 analysis. RESULTS. Thirty-nine highly active antiretroviral therapy–exposed and 24 control children were assessed. All mean scores were lower for those in the highly active antiretroviral therapy–exposed group than those in the control group (Bayley Mental Development Index: 85.4 vs 94.3; Bayley Psychomotor Development Index: 93.4 vs 96.6; Vineland mean communication score: 90.1 vs 94.4; Vineland mean daily-living score: 91.2 vs 93.6; Vineland mean socialization score: 97.1 vs 98.4). However, when maternal substance use during pregnancy was controlled for, there were no significant differences between the groups in any domains assessed. Children in both groups exposed to maternal substance use scored significantly lower than children not exposed in all domains except communication skills. It is important to note that there were no differences between the highly active antiretroviral therapy–exposed children with no substance exposure and the control children with no substance exposure in any of the scores. CONCLUSIONS. HIV- and highly active antiretroviral therapy–exposed HIV-uninfected children had lower development and adaptive behavior scores when compared with children who had not been exposed. However, these differences were not significant after correcting for maternal substance use, which had a greater impact on neurodevelopment than highly active antiretroviral therapy exposure. These results suggest that perinatal highly active antiretroviral therapy exposure is not associated with altered development and behavior at 18 to 36 months of age.

Leukocyte Telomere Length in HIV-Infected and HIV-Exposed Uninfected Children: Shorter Telomeres with Uncontrolled HIV Viremia

Objectives Nucleoside reverse transcriptase inhibitors (NRTIs) used in HIV antiretroviral therapy can inhibit human telomerase reverse transcriptase. We therefore investigated whether in utero or childhood exposure to NRTIs affects leukocyte telomere length (LTL), a marker of cellular aging. Methods In this cross-sectional CARMA cohort study, we investigated factors associated with LTL in HIV -1-infected (HIV+) children (n = 94), HIV-1-exposed uninfected (HEU) children who were exposed to antiretroviral therapy (ART) perinatally (n = 177), and HIV-unexposed uninfected (HIV−) control children (n = 104) aged 0–19 years. Univariate followed by multivariate linear regression models were used to examine relationships of explanatory variables with LTL for: a) all subjects, b) HIV+/HEU children only, and c) HIV+ children only. Results After adjusting for age and gender, there was no difference in LTL between the 3 groups, when considering children of all ages together. In multivariate models, older age and male gender were associated with shorter LTL. For the HIV+ group alone, having a detectable HIV viral load was also strongly associated with shorter LTL (p = 0.007). Conclusions In this large study, group rates of LTL attrition were similar for HIV+, HEU and HIV− children. No associations between children’s LTL and their perinatal ART exposure or HIV status were seen in linear regression models. However, the association between having a detectable HIV viral load and shorter LTL suggests that uncontrolled HIV viremia rather than duration of ART exposure may be associated with acceleration of blood telomere attrition.

Serious toxicity associated with continuous nevirapine-based HAART in pregnancy

Objective  This study was designed to determine the safety of nevirapine (NVP)‐based highly active antiretroviral therapy (HAART) in a cohort of HIV‐positive pregnant women.

Evaluation of an Emergency Prevention Program for Mother to Child Transmission of HIV in British Columbia

INTRODUCTION The objective of this study was to evaluate a province-wide program designed to identify HIV infection accurately and to prevent mother to child transmission among high-risk pregnant women of unknown serostatus. METHODS Between 2000 and 2007, 347 high-risk women were identified through the Prevention of Mother to Child Transmission (PMTCT) program implemented in 27 hospitals across British Columbia. Rates of HIV transmission and details of the implementation of prophylaxis kits were assessed. RESULTS Of the 346 high-risk mother-infant pairs identified and included in the provincial program, 35.4% of the mothers and 95.7% of infants received antiretroviral therapy for prevention of vertical transmission. Of 309 pairs who subsequently underwent HIV testing, five mothers were found to be HIV positive, an infection rate of 16.2/1000 in this cohort; the overall rate in BC is 0.68/1000 births. One of the five infants born to an HIV positive mother was infected with HIV. DISCUSSION The program was successful in identifying a subgroup of pregnant women at increased risk of HIV infection; however, mother to child transmission occurred in one of five cases (20%). To reduce the risk of mother to child HIV transmission in BC to the lowest possible level, additional strategies such as increasing uptake of prenatal screening and point-of-care testing in labour and delivery may need to be explored.

Blood Mitochondrial DNA Content in HIV-Exposed Uninfected Children with Autism Spectrum Disorder

Long-term outcomes of perinatal exposure to maternal antiretroviral therapy in HIV-exposed uninfected (HEU) children are unknown. However, both HIV antiretroviral therapy and autism spectrum disorder (ASD) have been associated with mitochondrial alterations. Leukocyte mitochondrial DNA (mtDNA) content can serve as a marker for mitochondrial dysfunction. In this cross-sectional, nested case-control study, HEU children with ASD were matched approximately 1:3 on age, sex, and ethnicity to HEU children without ASD, HIV-unexposed uninfected (HUU) controls, and HUU children with ASD. Leukocyte mtDNA content was measured using quantitative PCR. Among 299 HEU in this study, 14 (4.7%) were diagnosed with ASD, which is higher than the general population prevalence estimates. HEU children without ASD and HUU children with ASD had higher mtDNA content than HUU controls. HEU children with ASD had significantly higher mtDNA content than all other study groups. Our results suggest a clear association between elevated leukocyte mtDNA content and both HEU and ASD status. This may implicate mitochondrial dysfunction as a contributor to the high ASD prevalence observed in our cohort.

Do protease inhibitor-containing combination antiretroviral therapy regimens increase risk of spontaneous preterm birth in pregnant HIV-Positive women?

administration with a meal or soft foods, and the impact of high doses of secnidazole on cardiac safety. SYM-1219 was administered in either applesauce, yogurt, or pudding, followed by 240 mL of water. Serial blood samples were collected to determine secnidazole plasma concentrations and PK parameters for each treatment group are reported. Safety assessments, ECGs, and vital signs were performed during each study. An in vitro metabolism program, including CYP metabolism, inhibition, and induction, substrate and inhibition potential for transporters, and the potential for secnidazole to inhibit ethanol metabolism was performed. RESULTS: A single 2-g oral dose of SYM-1219 achieves an average maximum plasma secnidazole concentration (Cmax) of 35.7 to 46.3 mg/mL approximately 2 to 3 hours after dosing (Tmax). Exposure, as assessed by area under the plasma-concentration time curve (AUC), increases linearly with dose. Secnidazole has a prolonged terminal elimination half-life (t1/2) of w17 hours. SYM-1219 can be administered in applesauce, pudding, or yogurt and the timing and content of a meal does not have an impact on drug bioavailability. Secnidazole is not a substrate or inhibitor of transporters nor does it induce or inhibit hepatic CYP450 enzymes, therefore the potential for clinically important interactions with CYP450 substrates, inhibitors, or inducers is minimal. In a clinical study, secnidazole had negligible impact on the PK of ethinyl estradiol or norethindrone, suggesting that a single dose of SYM-1219 will not impact the efficacy of oral contraceptives. Secnidazole does not inhibit aldehyde dehydrogenase in vitro and therefore does not alter ethanol metabolism. There were no clinically significant abnormalities in laboratory, vital signs, or ECGs following administration of SYM-1219 to study subjects. CONCLUSIONS: The favorable safety and efficacy profile of SYM-1219, coupled with its PK characteristics, are the foundation for this single-dose oral treatment regimen for BV.

Evidence of Subclinical mtDNA Alterations in HIV-Infected Pregnant Women Receiving Combination Antiretroviral Therapy Compared to HIV-Negative Pregnant Women

Introduction Combination antiretroviral therapy (cART) can effectively prevent vertical transmission of HIV but there is potential risk of adverse maternal, foetal or infant effects. Specifically, the effect of cART use during pregnancy on mitochondrial DNA (mtDNA) content in HIV-positive (HIV+) women is unclear. We sought to characterize subclinical alterations in peripheral blood mtDNA levels in cART-treated HIV+ women during pregnancy and the postpartum period. Methods This prospective longitudinal observational cohort study enrolled both HIV+ and HIV-negative (HIV-) pregnant women. Clinical data and blood samples were collected at three time points in pregnancy (13-<23 weeks, 23-<30 weeks, 30–40 weeks), and at delivery and six weeks post-partum in HIV+ women. Peripheral blood mtDNA to nuclear DNA (nDNA) ratio was measured by qPCR. Results Over a four year period, 63 HIV+ and 42 HIV- women were enrolled. HIV+ women showed significantly lower mtDNA/nDNA ratios compared to HIV- women during pregnancy (p = 0.003), after controlling for platelet count and repeated measurements using a multivariable mixed-effects model. Ethnicity, gestational age (GA) and substance use were also significantly associated with mtDNA/nDNA ratio (p≤0.02). Among HIV+ women, higher CD4 nadir was associated with higher mtDNA/nDNA ratios (p<0.0001), and these ratio were significantly lower during pregnancy compared to the postpartum period (p<0.0001). Conclusions In the context of this study, it was not possible to distinguish between mtDNA effects related to HIV infection versus cART therapy. Nevertheless, while mtDNA levels were relatively stable over time in both groups during pregnancy, they were significantly lower in HIV+ women compared to HIV- women. Although no immediate clinical impact was observed on maternal or infant health, lower maternal mtDNA levels may exert long-term effects on women and children and remain a concern. Improved knowledge of such subclinical alterations is another step toward optimizing the safety and efficacy of cART regimens during pregnancy.