An observational cohort study to investigate the impact of dolutegravir in pregnancy and its obesogenic effects on the metabolic health of women living with HIV and their children: Study protocol.

INTRODUCTION: Dolutegravir (DTG)-based antiretroviral therapy is the World Health Organization's preferred first-line regimen for all persons with HIV, including pregnant women. While DTG has been implicated as an obesogen associated with greater weight gain compared to other antiretrovirals, there is a paucity of data in pregnant women and their children. The Obesogenic oRigins of maternal and Child metabolic health Involving Dolutegravir (ORCHID) study is investigating associations between DTG, weight gain, and metabolic outcomes in the context of HIV. MATERIALS & METHODS: ORCHID is a prospective observational study taking place in Cape Town, South Africa (NCT04991402). A total of 1920 pregnant women with and without HIV infection are being followed from ≤18 weeks gestational age to 24 months postpartum with their children. Participants attend eleven study visits: 3 antenatal, delivery, and 7 postnatal visits. Several embedded sub-studies address specific scientific aims. Primary outcome measurements in mothers include anthropometry, blood pressure, body composition, dysglycemia, insulin resistance (IR), and dyslipidemia. Other maternal measures include demographics, resting energy expenditure, viral load, physical activity, dietary intake, hepatic steatosis, and repository specimens. Sub-study measurements include markers of adipose inflammation, gut integrity, and satiety/hunger, subcutaneous adipose tissue morphology and mitochondrial function, and metabolomics. Primary outcome measurements in children include anthropometry, adipose tissue mass, dysglycemia, IR, and dyslipidemia. Other variables include fetal growth, birth outcomes, medical/breastfeeding history, caloric intake, neurodevelopment, and repository specimens. Sub-study measurements include metabolites/lipid subspecies in umbilical cord blood, as well as breast milk composition and DTG exposure. DISCUSSION: ORCHID will play a pivotal role in defining obesogenic mechanisms and clinical consequences of DTG use in pregnancy in women with HIV and their children. It will provide insights into metabolic disease risk reduction in the context of HIV/DTG, identify intervention targets, and inform public health approaches to diminish chronic metabolic co-morbidities for women and children.

Spatial hepatocyte plasticity of gluconeogenesis during the metabolic transitions between fed, fasted and starvation states.

The liver acts as a master regulator of metabolic homeostasis in part by performing gluconeogenesis. This process is dysregulated in type 2 diabetes, leading to elevated hepatic glucose output. The parenchymal cells of the liver (hepatocytes) are heterogeneous, existing on an axis between the portal triad and the central vein, and perform distinct functions depending on location in the lobule. Here, using single cell analysis of hepatocytes across the liver lobule, we demonstrate that gluconeogenic gene expression ( Pck1 and G6pc ) is relatively low in the fed state and gradually increases first in the periportal hepatocytes during the initial fasting period. As the time of fasting progresses, pericentral hepatocyte gluconeogenic gene expression increases, and following entry into the starvation state, the pericentral hepatocytes show similar gluconeogenic gene expression to the periportal hepatocytes. Similarly, pyruvate-dependent gluconeogenic activity is approximately 10-fold higher in the periportal hepatocytes during the initial fasting state but only 1.5-fold higher in the starvation state. In parallel, starvation suppresses canonical beta-catenin signaling and modulates expression of pericentral and periportal glutamine synthetase and glutaminase, resulting in an enhanced pericentral glutamine-dependent gluconeogenesis. These findings demonstrate that hepatocyte gluconeogenic gene expression and gluconeogenic activity are highly spatially and temporally plastic across the liver lobule, underscoring the critical importance of using well-defined feeding and fasting conditions to define the basis of hepatic insulin resistance and glucose production.

Lower Insulin Sensitivity Through 36 Months of Life With in Utero HIV and Antiretroviral Exposure in Botswana: Results From the Tshilo Dikotla Study.

BACKGROUND: There are little data on changes in insulin sensitivity during the first few years of life following in utero human immunodeficiency virus (HIV) and antiretroviral (ARV) exposure. METHODS: The Tshilo Dikotla study enrolled pregnant persons with HIV (PWH) (receiving tenofovir/emtricitabine or lamivudine plus dolutegravir or efavirenz) and pregnant individuals without HIV, as well as their liveborn children. Newborns were randomized to receive either zidovudine (AZT) or nevirapine (NVP) postnatal prophylaxis. Homeostasis Model Assessment for Insulin Resistance (HOMA-IR) was assessed at birth and 1, 18, 24, and 36 months of life. We fit linear mixed-effects models to evaluate the association between in utero HIV/ARV exposure and average HOMA-IR from birth through 36 months of life, adjusting for confounders. RESULTS: A total of 419 children were included (287 with in utero HIV/ARV exposure and uninfected [CHEU] and 132 without in utero HIV/ARV exposure [CHUU]). CHEU were born to older women (29.6 vs 25.3 years of age) with higher gravidity (3 vs 1). HOMA-IR was persistently higher in CHEU versus CHUU in adjusted analyses (mean difference of 0.07 in log10 HOMA-IR, P  = .02) from birth through 36 months of life. Among CHEU, no differences in HOMA-IR were observed from birth through 36 months by in utero ARV exposure status or between AZT and NVP infant prophylaxis arms. CONCLUSIONS: In utero HIV/ARV exposure was associated with lower insulin sensitivity throughout the first 36 months of life, indicating persistent early life metabolic disturbances which may raise concern for poorer metabolic health later in life.

FITM2 deficiency results in ER lipid accumulation, ER stress, reduced apolipoprotein B lipidation, and VLDL triglyceride secretion in vitro and in mouse liver.

Objectives: Triglyceride (TG) association with apolipoprotein B100 (apoB100) serves to form very low density lipoproteins (VLDL) in the liver. The repertoire of factors that facilitate this association is incompletely defined. FITM2, an integral endoplasmic reticulum (ER) protein, was originally discovered as a factor participating in cytoplasmic lipid droplets (LDs) in tissues that do not form VLDL. We hypothesized that in the liver, in addition to promoting cytosolic LD formation, FITM2 would also transfer TG from its site of synthesis in the ER membrane to nascent VLDL particles within the ER lumen. Methods: Experiments were conducted using a rat hepatic cell line (McArdle-RH7777, or McA cells), an established model of mammalian lipoprotein metabolism, and mice. FITM2 expression was reduced using siRNA in cells and by liver specific cre-recombinase mediated deletion of the Fitm2 gene in mice. Effects of FITM2 deficiency on VLDL assembly and secretion in vitro and in vivo were measured by multiple methods, including density gradient ultracentrifugation, chromatography, mass spectrometry, simulated Raman spectroscopy (SRS) microscopy, sub-cellular fractionation, immunoprecipitation, immunofluorescence, and electron microscopy. Main findings: 1) FITM2-deficient hepatic cells in vitro and in vivo secrete TG-depleted VLDL particles, but the number of particles is unchanged compared to controls; 2) FITM2 deficiency in mice on a high fat diet (HFD) results in decreased plasma TG levels. The number of apoB100-containing lipoproteins remains similar, but shift from VLDL to LDL density; 3) Both in vitro and in vivo , when TG synthesis is stimulated and FITM2 is deficient, TG accumulates in the ER, and despite its availability this pool is unable to fully lipidate apoB100 particles; 4) FITM2 deficiency disrupts ER morphology and results in ER stress. Principal conclusions: The results suggest that FITM2 contributes to VLDL lipidation, especially when newly synthesized hepatic TG is in abundance. In addition to its fundamental importance in VLDL assembly, the results also suggest that under dysmetabolic conditions, FITM2 may be a limiting factor that ultimately contributes to non-alcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH).