Immunoliposomal drug-delivery system targeting lectin-like oxidized low-density lipoprotein receptor–1 for carotid plaque lesions in rats

Object

Targeted drug delivery with immunoliposomes has been applied to various in vivo animal models and is newly focused as a novel therapeutic target. Lectin-like oxidized low-density lipoprotein receptor–1 (LOX1) is a potent regulator of systemic atherosclerosis, and the authors focused on its effect on carotid plaques. The authors developed a LOX1-targeted liposomal rho-kinase inhibitor and examined the therapeutic effect on carotid intimal hypertrophy in rats.

Methods

LOX1-targeted rho-kinase inhibitor fasudil-containing liposomes, composed of hydrogenated soy phosphatidylcholine/cholesterol/PEG2000-DSPE, were prepared by conjugating anti-LOX1 antibodies on the surface and by remote loading of fasudil. Carotid intimal hypertrophy was induced by balloon injury, and the drugs were intravenously administered on Day 3 postinjury. The rats were divided into 4 groups: nontreatment, treatment with intravenous fasudil (2 mg), treatment with liposomal fasudil (2 mg), and treatment with LOX1-targeted liposomal fasudil (2 mg). The authors compared intimal hypertrophy, atherosclerotic factor, and matrix metalloproteinase-9 expression among groups.

Results

DiI–labeled LOX1-targeted liposomes were prominently observed in the lesions on Day 7 after the surgery. The intimal thickness was significantly reduced in the LOX1-targeted liposomal fasudil–treated group (mean 81.6 ± 13.9 μm) compared with the other groups (no treatment 105.4 ± 16.8 μm; fasudil treatment 102.4 ± 20.0 μm; and liposomal fasudil treatment 102.8 ± 22.2 μm; p = 0.046). Matrix metalloproteinase-9 expression was also significantly reduced in the LOX1-targeted liposomal fasudil group.

Conclusions

Liposomes conjugated with anti-LOX1 antibody effectively reached carotid artery lesions, and liposomal rho-kinase significantly inhibited intimal hypertrophy. The new liposomal drug delivery system targeting LOX1 may become a therapeutic strategy for atherosclerotic diseases.

Subarachnoid hemorrhage and the distribution of drugs delivered into the cerebrospinal fluid. Laboratory investigation

OBJECT

Investigators in experimental and clinical studies have used the intrathecal route to deliver drugs to prevent or treat vasospasm. However, a clot near an artery or arteries after subarachnoid hemorrhage (SAH) may hamper distribution and limit the effects of intrathecally delivered compounds. In a primate model of right middle cerebral artery (MCA) SAH, the authors examined the distribution of Isovue-M 300 and 3% Evans blue after infusion into the cisterna magna CSF.

METHODS

Ten cynomolgus monkeys were assigned to SAH and sham SAH surgery groups (5 in each group). Monkeys received CSF injections as long as 28 days after SAH and were killed 3 hours after the contrast/Evans blue injection. The authors assessed the distribution of contrast material on serial CT within 2 hours after contrast injection and during autopsy within 3 hours after Evans blue staining.

RESULTS

Computed tomography cisternographies showed no contrast in the vicinity of the right MCA (p < 0.05 compared with left); the distribution of contrast surrounding the entire right cerebral hemisphere was substantially reduced. Postmortem analysis demonstrated much less Evans blue staining of the right hemisphere surface compared with the left. Furthermore, the Evans blue dye did not penetrate into the right sylvian fissure, which occurred surrounding the left MCA. The authors observed the same pattern of changes and differences in contrast distribution between SAH and sham SAH animals and between the right and the left hemispheres on Days 1, 3, 7, 14, 21, and 28 after SAH.

CONCLUSIONS

Intrathecal drug distribution is substantially limited by SAH. Thus, when using intrathecal drug delivery after SAH, vasoactive drugs are unlikely to reach the arteries that are at the highest risk of delayed cerebral vasospasm.