Selective boron delivery by intra-arterial injection of BSH-WOW emulsion in hepatic cancer model for neutron capture therapy.

OBJECTIVE: Boron neutron-capture therapy (BNCT) has been used to inhibit the growth of various types of cancers. In this study, we developed a 10BSH-entrapped water-in-oil-in-water (WOW) emulsion, evaluated it as a selective boron carrier for the possible application of BNCT in hepatocellular carcinoma treatment. METHODS: We prepared the 10BSH-entrapped WOW emulsion using double emulsification technique and then evaluated the delivery efficacy by performing biodistribution experiment on VX-2 rabbit hepatic tumour model with comparison to iodized poppy-seed oil mix conventional emulsion. Neutron irradiation was carried out at Kyoto University Research Reactor with an average thermal neutron fluence of 5 × 1012 n cm-2. Morphological and pathological analyses were performed on Day 14 after neutron irradiation. RESULTS: Biodistribution results have revealed that 10B atoms delivery with WOW emulsion was superior compared with those using iodized poppy-seed oil conventional emulsion. There was no dissemination in abdomen or lung metastasis observed after neutron irradiation in the groups treated with 10BSH-entrapped WOW emulsion, whereas many tumour nodules were recognized in the liver, abdominal cavity, peritoneum and bilateral lobes of the lung in the non-injected group. CONCLUSION: Tumour growth suppression and cancer-cell-killing effect was observed from the morphological and pathological analyses of the 10BSH-entrapped WOW emulsion-injected group, indicating its feasibility to be applied as a novel intra-arterial boron carrier for BNCT. Advances in knowledge: The results of the current study have shown that entrapped 10BSH has the potential to increase the range of therapies available for hepatocellular carcinoma which is considered to be one of the most difficult tumours to cure.

Evaluation of ABCG2 and p63 expression in canine cornea and cultivated corneal epithelial cells.

OBJECTIVE: To examine the expressions of ABCG2 and p63 in canine corneal epithelia and to evaluate their significance in corneal regeneration. PROCEDURES: Canine corneal and limbal epithelial cells were obtained from five healthy beagle dogs. We analyzed the morphological properties of cultivated limbal and corneal epithelial cells. We compared the expressions of ABCG2 and p63 in the limbus and central cornea by immunohistochemistry and real-time quantitative PCR. We analyzed the expression of these markers in cultivated cells by immunocytochemistry and real-time quantitative PCR. RESULTS: The limbal epithelial cells were smaller and proliferated more rapidly than the corneal epithelial cells in primary cultures. The corneal cells failed to be subcultured, whereas the limbal cells could be subcultured with increasing cell size. ABCG2 was localized in the basal layer of the limbal epithelium, and p63 was widely detected in the entire corneal epithelia. ABCG2 expression was significantly higher, and p63 was slightly higher in the limbus compared with the central cornea. ABCG2 was detected only in limbal cells in primary culture, not in corneal cells or passaged limbal cells. p63 was detected in both limbal and corneal cells and decreased gradually in the limbal cells with the cell passages. CONCLUSIONS: ABCG2 was localized in canine limbal epithelial cells, and p63 was widely expressed in canine corneal epithelia. ABCG2 and p63 could prove to be useful markers in dogs for putative corneal epithelial stem cells and for corneal epithelial cell proliferation, respectively.

Olfactory ensheathing cells (OECs) degrade neurocan in injured spinal cord by secreting matrix metalloproteinase-2 in a rat contusion model.

The mechanism by which olfactory ensheathing cells (OECs) exert their potential to promote functional recovery after transplantation into spinal cord injury (SCI) tissue is not fully understood, but the relevance of matrix metalloproteinases (MMPs) has been suggested. We evaluated the expression of MMPs in OECs in vitro and the MMP secretion by OECs transplanted in injured spinal cord in vivo using a rat SCI model. We also evaluated the degradation of neurocan, which is one of the axon-inhibitory chondroitin sulfate proteoglycans, using SCI model rats. The in vitro results showed that MMP-2 was the dominant MMP expressed by OECs. The in vivo results revealed that transplanted OECs secreted MMP-2 in injured spinal cord and that the expression of neurocan was significantly decreased by the transplantation of OECs. These results suggest that OECs transplanted into injured spinal cord degraded neurocan by secreting MMP-2.

A comparison of neurosphere differentiation potential of canine bone marrow-derived mesenchymal stem cells and adipose-derived mesenchymal stem cells.

Stem cell transplantation is one of the most promising yet enigmatic treatments for spinal cord injury (SCI), a common problem in dogs. As pre-differentiated mesenchymal stem cells (MSCs) can be expanded and differentiated into neurospheres in vitro, before being transplanted back, they may prove to be more beneficial for treating SCI. Therefore, we compared the endogenous differentiation potential, including the neuronal cell differentiation, of neurospheres from canine bone marrow MSCs (cBMMSCs) with that of the adipose tissue-derived MSCs (cADMSCs). Nestin-positive neurospheres were generated from MSCs derived from the bone marrow and adipose tissue. Neuronal cells were differentiated from the neurospheres derived from both these tissues. Gene expression analysis revealed that Nestin, ßIII-tubulin, NCAM, OCT4 and SOX2 were expressed in MSCs and the corresponding neurospheres. Notably, cBMMSC-derived neuronal cells expressed higher levels of ßIII-tubulin. The mRNA expressions of NANOG, Nestin, OCT4 and SOX2 were upregulated in neurospheres derived from both. Immunofluorescence analysis detected the expression of neuronal markers, namely, ßIII-tubulin, GFAP, S100, NF200 and MAP2, in differentiated neuron-like cells. Our findings highlight that both cBMMSCs and cADMSCs could be differentiated into neurospheres and neuron-like cells, and therefore, these cells are suitable candidates for cell transplantation. Further, cADMSCs form a more suitable cell source, as larger number of cells could be harvested from cADMSC-derived neurospheres. Future studies employing in vivo transplantation models to investigate the effectiveness of MSCs for treating SCI are warranted.

Effects of fibroblasts derived from the olfactory bulb and nasal olfactory mucosa on proliferation of olfactory ensheathing cells harvested from the olfactory bulb.

Olfactory ensheathing cells (OECs) have been reported to promote axonal regeneration when transplanted to rodent spinal cord injury models. OECs are available from the olfactory bulb (OB) and olfactory mucosa (OM). Although harvesting OECs from the OM is less traumatic, OECs originating from the OM are less proliferative than those from the OB (OB-OECs). One possible reason for this difference is coexisting fibroblasts. Here, we examined the effect of coculturing either fibroblasts from the OB (OB-Fibs) or fibroblasts from the OM (OM-Fibs) on the proliferation of OB-OECs. Proliferation of OB-OECs was significantly higher in 5:5 coculture with OB-Fibs and in 7:3 and 5:5 cocultures with OM-Fibs than without fibroblasts. These results indicated that coculture with both OB-Fibs and OM-Fibs promoted the proliferation of OB-OECs.