Tanshinone IIA-Loaded Nanoparticle and Neural Stem Cell Therapy Enhances Recovery in a Pig Ischemic Stroke Model

Abstract

Induced pluripotent stem cell-derived neural stem cells (iNSCs) are a multimodal stroke therapeutic that possess neuroprotective, regenerative, and cell replacement capabilities post-ischemia. However, long-term engraftment and efficacy of iNSCs is limited by the cytotoxic microenvironment post-stroke. Tanshinone IIA (Tan IIA) is a therapeutic that demonstrates anti-inflammatory and antioxidative effects in rodent ischemic stroke models and stroke patients. Therefore, pretreatment with Tan IIA may create a microenvironment that is more conducive to the long-term survival of iNSCs. In this study, we evaluated the potential of Tan IIA drug-loaded nanoparticles (Tan IIA-NPs) to improve iNSC engraftment and efficacy, thus potentially leading to enhanced cellular, tissue, and functional recovery in a translational pig ischemic stroke model. Twenty-two pigs underwent middle cerebral artery occlusion (MCAO) and were randomly assigned to a PBS + PBS, PBS + iNSC, or Tan IIA-NP + iNSC treatment group. Magnetic resonance imaging (MRI), modified Rankin Scale neurological evaluation, and immunohistochemistry were performed over a 12-week study period. Immunohistochemistry indicated pretreatment with Tan IIA-NPs increased iNSC survivability. Furthermore, Tan IIA-NPs increased iNSC neuronal differentiation and decreased iNSC reactive astrocyte differentiation. Tan IIA-NP + iNSC treatment enhanced endogenous neuroprotective and regenerative activities by decreasing the intracerebral cellular immune response, preserving endogenous neurons, and increasing neuroblast formation. MRI assessments revealed Tan IIA-NP + iNSC treatment reduced lesion volumes and midline shift. Tissue preservation and recovery corresponded with significant improvements in neurological recovery. This study demonstrated pretreatment with Tan IIA-NPs increased iNSC engraftment, enhanced cellular and tissue recovery, and improved neurological function in a translational pig stroke model.

Tanshinone IIA-loaded nanoparticles and neural stem cell combination therapy improves gut homeostasis and recovery in a pig ischemic stroke model

“…Previously, our research team reported that intracisternal administration of Tan IIA-NPs and iNSCs transplantation therapy reduced brain tissue damage 12 weeks PT compared to the non-treated control group 21 . In this study, we correlated changes in gut SCFAs levels with stroke-induced tissue damage at 12 weeks PT (Table 2 ).…”

“…In this study, the combination of Tan IIA-NPs and iNSCs was used as a treatment. In the same pig cohort, our team found that the Tan IIA-NP + iNSC treatment had smaller lesion volume and midline shift 1 day post-stroke and 12 weeks post-treatment compared to the control and the iNSC only treated group 21 . This MRI result at 1 day post-stroke indicates that Tan IIA-NP alone have a neuroprotective effect on stroke injury because iNSCs were not transplanted until 5 days post-stroke.…”

“…During stroke, damaged and dying neural cells release damaged-associated molecular patterns (DAMPs) that activate microglia and astrocytes at the lesion site and enhance recruitment and parenchymal invasion of leukocytes from peripheral circulation 28 . Recently, our research team demonstrated that treatment with Tan IIA-NP + iNSC reduced the number of microglial and infiltrating immune cells in the brain, maintained endogenous neurons, and enhanced populations of endogenous neural stem cells in pigs 21 . Activated microglia and macrophages release proinflammatory cytokines such as TNF-α and IL-1β in the brain 29 .…”

“…A total of 6 animals per group that survived to the end of the experimental period were analyzed as part of this study. A more detailed method of Tan IIA-NPs injection and iNSCs transplantation can be found in Kaiser et al 21 .

Figure 5 Experimental study design.

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“…In a separate study, our research team demonstrated that induced pluripotent stem cell-derived neural stem cells (iNSCs) transplanted into the brain acutely after stroke can replace damaged and dead neurons and glia and improve white matter integrity, cerebral blood perfusion, and brain metabolism in a pig model of ischemic stroke 20 . The combination of Tan IIA-NPs and iNSCs improved efficacy and engraftment of iNSCs, brain tissue recovery, and neurological function during the chronic stages of ischemic stroke in the porcine model 21 . However, questions remain as to how brain-targeted stroke therapies alter the GI system and potentially inhibit GI induced systemic and secondary inflammation in the stroke brain.…”