Methamphetamine (Meth), a psychoactive drug, has been shown to reduce testicular weight and decrease sperm count, indicating its potential role in contributing to male infertility. We therefore assessed Meth's effects (0.1-100 μM) on TM4 Sertoli cell viability, toxicity, and proliferation (trypan blue exclusion assay), mitochondrial activity (MA) (XTT assay), while transepithelial electrical resistance (TEER) was used to examine monolayer permeability. The acute study (only 24-hour Meth exposure) mimics recreational users and the chronic study, the Meth addicts who require daily doses (24-96 hours). Acute Meth treatment had minimal impact on TM4 Sertoli cell viability and toxicity, while chronic exposure resulted in reduced cell viability and increased toxicity in a dose-related manner. Acute exposure suppressed cell division at 72 hours, while chronic exposure suppressed cell division at both 72 and 96 hours. Long-term suppression of MA was observed for both acute and chronic Meth exposure (20 µM and 100 µM). Both acute and chronic Meth exposure affected permeability across the blood-testis barrier (BTB), which persisted for up to 96 hours. Given the pivotal role of Sertoli cells in spermatogenesis, our findings provide a two-pronged mechanism for Meth-induced male infertility and indicate that short-term exposure may have long-term effects on the germinal epithelium.

Cerebral malaria (CM) is a severe neurological complication of Plasmodium falciparum infection associated with endothelial activation, neuroinflammation, and disruption of the blood-brain barrier (BBB). While curcumin (Cur) possesses antiplasmodial and anti-inflammatory properties, its therapeutic potential is limited by poor aqueous solubility, rapid metabolism, and insufficient brain bioavailability. In this study, we hypothesized that polysaccharide-driven surface engineering could regulate nanoparticles (NPs) interfacial properties to improve BBB compatibility and antiplasmodial efficacy. Cur-loaded polycaprolactone (PCL) NPs were fabricated through a single-emulsion solvent evaporation technique and sequentially coated with chitosan (CS) and hyaluronic acid (HA) to establish defined structure-property relationships. The resulting nanoformulations were characterized for particle size, surface charge, polysaccharide deposition, encapsulation efficiency (EE), and release kinetics. In-vitro biological performance was evaluated through hemocompatibility, brain endothelial cell viability, BBB integrity through transendothelial electrical resistance measurements, and in-vitro antiplasmodial activity against P. falciparum FCR3. Dual polysaccharide coating produced stable NPs with controlled size, enhanced surface charge, sustained Cur release, and significantly improved endothelial compatibility compared with free Cur and non-hyaluronic-acid formulations. Notably, HA coating strengthened BBB integrity and enhanced antiplasmodial potency. These findings demonstrate that CS- HA surface functionalization governs critical structure-property relationships, highlighting the potential of polysaccharide-engineered nanocarriers for adjunctive CM drug delivery.

Cancer remains a major global concern, with metastasis responsible for most cancer-related deaths. Disseminated cancer cells become circulating tumour cells (CTCs) that travel until arresting at preferential vascular sites such as the blood-brain barrier (BBB), where they cross into the central nervous system (CNS). Given that the BBB robustly maintains CNS homeostasis, the mechanism whereby CTCs metastatically enter the brain is largely unknown. The triple-negative breast cancer (TNBC) (MDA-MB-231 cell line) cells were cultured under normoxic (21% O₂), physioxic (5% O₂), and hypoxic (1.5-2% O₂) conditions to generate conditioned media (CM). Diluted CM was used to treat brain endothelial cells (BECs: bEnd.5 cell line). Endothelial suppression of cell division was assessed using the trypan blue exclusion assay. Morphological changes and an abnormality index were evaluated using hematoxylin and eosin (H&E) staining. Transendothelial electrical resistance (TEER) measured the BEC monolayer integrity following CM exposure. Comparatively, all oxygen-derived CM suppressed BEC suppression of cellular division; however, hypoxic-derived CM was most severe, reducing cell division by 67.7% at 96 h. H&E staining similarly showed that hypoxic-derived CM induced an abnormality rate of 980 abnormalities per 1 000 cells. TEER measurements demonstrated that the hypoxic-derived CM overwhelmed BEC homeostatic mechanisms, significantly increasing monolayer permeability. A clear pattern of progressive dysfunction correlated with decreasing oxygen tension in MDA-MB-231 cell cultures. While the normoxic and physioxic CM had comparable effects, hypoxic-derived CM elicited exacerbated responses, with substantial impairment detectable as soon as 24 h. These findings suggest hypoxic tumour secretomes overwhelm the endothelial regulatory mechanisms, leading to BEC dysfunction and, ultimately, BBB compromise. Graphical Abstract The alternative text for this image may have been generated using AI. Illustration of breast cancer circulating tumour cells (CTCs) origin and metastasis to the blood-brain barrier (BBB). Illustrations from Server Medical Art (https://smart.servier.com), used under CC BY 4.0 license (https://creativecommons.org/licenses/by.4.0/).

The blood–brain barrier (BBB) is a dynamic endothelial interface that protects the brain from harmful agents while regulating molecular exchange. Human immunodeficiency virus (HIV) compromises BBB integrity, promoting neurological damage. Antiretroviral (ARV) therapies suppress HIV replication, preventing immune system deterioration and progression to AIDS. Although Tenofovir‐based ARV regimens are vital for HIV treatment and prevention, their impact on cerebrovascular function remains unclear. Aim: This study examined Tenofovir's effects on murine brain endothelial cells using an in vitro BBB model. Methods: Brain endothelial cells (bEnd.5) were treated with Tenofovir Disoproxil Fumarate (TDF; 9.8–98 ng/mL) or Tenofovir Alafenamide (TAF; 1–10 ng/mL) for 24–96 h. Cell proliferation, cell cycle progression (via flow cytometry) and monolayer permeability (via Transendothelial Electrical Resistance) were evaluated. Results: Both TDF and TAF treatments suppressed cell division by S‐phase disruption of the cell cycle and increased monolayer permeability. Conclusion: These findings suggest that prolonged TDF or TAF exposure compromises BBB integrity by inhibiting endothelial cell division and altering barrier function, which could have implications for HIV‐ARV‐induced neurodegeneration in individuals receiving long‐term Tenofovir‐based therapy.

1. The blood-brain barrier (BBB) is an anatomical gateway that consists of highly selective semi-permeable endothelial cells. These brain endothelial cells (BECs) play a crucial role in maintaining...