Establishment of a Four-Cell In Vitro Blood-Brain Barrier Model With Human Primary Brain Cells.

The blood-brain barrier (BBB) constitutes a crucial protective anatomical layer with a microenvironment that tightly controls material transit. Constructing an in vitro BBB model to replicate in vivo features requires the sequential layering of constituent cell types. Maintaining heightened integrity in the observed tight junctions during both the establishment and post-experiment phases is crucial to the success of these models. We have developed an in vitro BBB model that replicates the cellular composition and spatial orientation of in vivo BBB observed in humans. The experiment includes comprehensive procedures and steps aimed at enhancing the integration of the four-cell model. Departing from conventional in vitro BBB models, our methodology eliminates the necessity for pre-coated plates to facilitate cell adhesion, thereby improving cell visualization throughout the procedure. An in-house coating strategy and a simple yet effective approach significantly reduce costs and provides superior imaging of cells and corresponding tight junction protein expression. Also, our BBB model includes all four primary cell types that are structural parts of the human BBB. With its innovative and user-friendly features, our in-house optimized in vitro four-cell-based BBB model showcases novel methodology and provides a promising experimental platform for drug screening processes. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Coating and culture system Basic Protocol 2: Cell seeding and Transwell insert handling Basic Protocol 3: Assessment of model functionality.

In-vitro and in-vivo assessment of nirmatrelvir penetration into CSF, central nervous system cells, tissues, and peripheral blood mononuclear cells.

Three years after SARS-CoV-2 emerged as a global infectious threat, the virus has become endemic. The neurological complications such as depression, anxiety, and other CNS complications after COVID-19 disease are increasing. The brain, and CSF have been shown as viral reservoirs for SARS-CoV-2, yielding a potential hypothesis for CNS effects. Thus, we investigated the CNS pharmacology of orally dosed nirmatrelvir/ritonavir (NMR/RTV). Using both an in vitro and an in vivo rodent model, we investigated CNS penetration and potential pharmacodynamic activity of NMR. Through pharmacokinetic modeling, we estimated the median CSF penetration of NMR to be low at 18.11% of plasma with very low accumulation in rodent brain tissue. Based on the multiples of the 90% maximal effective concentration (EC90) for SARS-CoV-2, NMR concentrations in the CSF and brain do not achieve an exposure level similar to that of plasma. A median of only 16% of all the predicted CSF concentrations in rats were > 3xEC90 (unadjusted for protein binding). This may have implications for viral persistence and neurologic post-acute sequelae of COVID-19 if increased NMR penetration in the CNS leads to decreased CNS viral loads and decreased CNS inflammation.

Twice-Daily Dolutegravir Based Antiretroviral Therapy with One Month of Daily Rifapentine and Isoniazid (1HP) for TB Prevention.

BACKGROUND: One month of daily rifapentine + isoniazid (1HP) is an effective, ultrashort option for TB prevention in people with HIV (PWH). However, rifapentine may decrease antiretroviral drug concentrations and increase the risk of virologic failure. ACTG A5372 evaluated the effect of 1HP on the pharmacokinetics of twice daily dolutegravir. METHODS: A5372 was a multicenter, pharmacokinetic study in PWH (≥18 years) already on dolutegravir-containing antiretroviral therapy with HIV RNA < 50 copies/mL. Participants received daily rifapentine/isoniazid (600mg/300mg) for 28 days as part of 1HP. Dolutegravir was increased to 50mg twice daily during 1HP and intensive pharmacokinetic sampling was performed on day 0 (before 1HP) and on the final day of 1HP treatment. RESULTS: Thirty-two participants (41% female; 66% Black/African; median (Q1, Q3) age 42 (34, 49) years) were included in the pharmacokinetic analysis. Thirty-one of 32 had HIV RNA levels <50 copies/mL at the end of 1HP dosing. One participant had an HIV RNA of 160 copies/mL at day 28, with HIV RNA <50 copies/mL upon repeat testing on day 42. The median (Q1, Q3) dolutegravir trough concentration was 1751 ng/mL (1195, 2542) on day 0 vs. 1987ng/mL (1331, 2278) on day 28 (day 28:day 0 GMR 1.05, [90% CI 0.93-1.2]; p = 0.43). No serious adverse events were reported. CONCLUSION: Dolutegravir trough concentrations with 50mg twice daily dosing during 1HP treatment were greater than those with standard dose dolutegravir once daily without 1HP. These pharmacokinetic, virologic, and safety data provide support for twice daily dolutegravir use in combination with 1HP for TB prevention.

The anti-HIV drug abacavir stimulates ß-catenin activity in osteoblast lineage cells.

Bone mineral density (BMD) loss in people living with HIV occurs with the initiation of combined antiretroviral therapy (cART), particularly with tenofovir disoproxil fumarate (TDF) containing cART. Switching from TDF to abacavir (ABC) or dolutegravir (DTG) leads to increased BMD. Whether BMD gains are due to cessation of TDF or anabolic effects of ABC or DTG is unclear. We investigated the effects of ABC and DTG on osteoblast lineage cells in vitro and in vivo. Primary human osteoblasts and male C57BL/6 mice were treated with individual antiretrovirals (ARVs) or a combination of ABC/DTG/lamivudine (3TC). Nearly all ARVs and cART inhibited osteogenic activity in vitro. Due to the importance of Wnt/ß-catenin in bone formation, we further investigated ARV effects on the Wnt/ß-catenin pathway. ABC, alone and as part of ABC/DTG/3TC, increased osteoblastic ß-catenin activity as indicated by increased TOPFlash activity, hypo-phosphorylated (active) ß-catenin staining, and ß-catenin targeted gene expression. Mice treated with TDF had decreased lumbar spine BMD and trabecular connectivity density in the vertebrae, while those treated with ABC/DTG/3TC reduced cortical area and thickness in the femur. Mice treated with ABC alone had no bone structural changes, increased circulating levels of the bone formation marker, P1NP, and elevated expression of the Wnt/ß-catenin target gene, Lef1, in osteocyte enriched samples. Further, bones from ARV-treated mice were isolated to evaluate ARV distribution. All ARVs were detected in the bone tissue, which was inclusive of bone marrow, but when bone marrow was removed, only TDF, ABC, and DTG were detected at ~0.1% of the circulating levels. Overall, our findings demonstrate that ABC activates Wnt/ß-catenin signaling, but whether this leads to increased bone formation requires further study. Assessing the impact of ARVs on bone is critical to informing ARV selection and/or discovery of regimens that do not negatively impact the skeleton.