Systemic Injection of CD34⁺-Enriched Human Cord Blood Cells Modulates Poststroke Neural and Glial Response in a Sex-Dependent Manner in CD1 Mice

Abstract

Stroke in the developing brain is an important cause of neurological morbidity. We determined the impact of human cord blood-derived CD34+ -enriched mononuclear cells (CBSC) intraperitoneally injected 48 h after an ischemic stroke at postnatal day 12 by evaluating poststroke neurogenic niche proliferation, glial response, and recovery in CD1 mice. Percent brain atrophy was quantified from Nissl-stained sections. Density of BrdU, Iba-1, and GFAP staining were quantified in the dentate gyrus and the subventricular zone (SVZ). Immunohistochemistry for human nuclear antibody, human mitochondrial antibody, and human CD34+ cells was done on injured and uninjured brains from CBSC-and vehicle-treated mice. Developmental neurobehavioral milestones were evaluated pre-and post-treatment. No significant differences in stroke severity were noted between CBSC and vehicle-treated injured animals. With a 1 · 10 5 CBSC dose, there was a significant increase in subgranular zone (SGZ) proliferation in the CBSC-versus vehicle-treated stroke-injured male mice. SVZ glial fibrillary acidic protein (GFAP) expression was increased contralaterally in injured females treated with CBSC but suppressed in injured males. Significant negative correlations between severity of the stroke-injury and spleen weights, and between spleen weights and SGZ proliferation, and a positive correlation between GFAP expression and severity of brain injury were noted in the vehicle-treated injured mice but not in the CBSC-treated mice. GFAP expression and SVZ proliferation were positively correlated. In conclusion, neurogenic niche proliferation and glial brain responses to CBSC after neonatal stroke may involve interactions with the spleen and are sex dependent.

Evaluations of Intravenous Administration of CD34⁺ Human Umbilical Cord Blood Cells in a Mouse Model of Neonatal Hypoxic-Ischemic Encephalopathy

“…In addition to this study and our previous studies, 1 other study has examined the effects of UCBC treatment for neonatal brain injury. Kadam et al [41] injected CD34 + -enriched hUCB cells intraperitoneally into P12 mice with permanent carotid artery occlusion. Although the cell treatment provided no significant improvement to stroke severity, it did increase cell proliferation significantly in the subgranular zone, where persistent neurogenesis continues throughout life.…”

Resident microglia, rather than blood‐derived macrophages, contribute to the earlier and more pronounced inflammatory reaction in the immature compared with the adult hippocampus after hypoxia‐ischemia

“…For quantification of immunopositive cells in the DG and the CA regions, ten consecutive 0.5μm z ‐stack images of the sections were acquired using Axio Imager M2 microscope with Apotome attachment (Carl Zeiss) at 20× magnification and compressed in a single image (Kadam et al, 2015). All immunopositive cells were counted in three to four sections per animal spaced 400 μm apart.…”

“…The analysis of resident microglia and blood-derived macrophages was performed by quantifying Cx3cr1-GFP-positive (Cx3cr1-GFP1) and Ccr2-RFP-positive (Ccr2-RFP1) cells in the entire dorsal DG region of the hippocampus (the granule cell layer including the subgranular zone) and the entire dorsal CA region of the hippocampus (the pyramidal cell layer from CA1-3) (Fanselow and Dong, 2010;Qiu et al, 2007). For quantification of immunopositive cells in the DG and the CA regions, ten consecutive 0.5lm z-stack images of the sections were acquired using Axio Imager M2 microscope with Apotome attachment (Carl Zeiss) at 203 magnification and compressed in a single image (Kadam et al, 2015). All immunopositive cells were counted in three to four sections per animal spaced 400 lm apart.…”

Systemic human CD34+ cells populate the brain and activate host mechanisms to counteract nigrostriatal degeneration

“…Stereological quantification of TH + dopaminergic neurons in the substantia nigra indicated a significantly (p < 0.001, one-way ANOVA, Tukey's post hoc test) greater preservation of these cells in the lesioned hemisphere of the CD34 + hCBC infused rats. (C) On average, CD34 + hCBC injected animals had 10,625.3 ± 1051.4 TH + cells in the lesioned SN (13,943.7 ± 843 cell in the intact hemisphere, p < 0.05, unpaired t-test), in comparison to CD34 − receiving animals which showed 5471.7 ± 1572.4 cells in the lesioned SN (14,544.2 ± 1409.5 cell in the intact side, p < 0.001, unpaired t-test). Animals in the only CD34 + group had 14,288 ± 424.6 and 13,985 ± 858.4 TH + cells in the lesioned and unlesioned hemispheres respectively.…”

“…Among the different cell types present in human cord blood, CD34 + mononuclear cells, which include hematopoietic stem and progenitor cells, show the ability to induce tissue protection and repair in models of neurodegeneration [9]. More specifically, these cells can induce regenerative and anti-inflammatory effects to promote cell survival and tissue homeostasis making them an attractive stem cell type to use in the context of early stages of DA neuron degeneration in PD [9,[13][14][15][16].…”