Organic Cation Transporter 1 Is Responsible for Hepatocellular Uptake of the Tyrosine Kinase Inhibitor Pazopanib.

Pazopanib is an orally active tyrosine kinase inhibitor that exhibits hepatotoxicity in some patients. Despite the clinical importance of its hepatic distribution, the transporter(s) responsible for hepatic uptake of pazopanib in humans remain undetermined. To characterize its hepatic uptake mechanism, we screened the effects of several transporter inhibitors, including tetrapentylammonium (TPeA) for organic cation transporters (OCTs) and cyclosporin A (CsA) for organic anion-transporting polypeptides (OATPs), on both plasma disappearance and hepatic distribution of pazopanib in mice after its i.v. administration. Among the inhibitors, TPeA largely reduced hepatic distribution and plasma clearance of pazopanib, whereas CsA showed only partial reduction. Pazopanib uptake by isolated mouse hepatocytes was similarly reduced by these inhibitors, suggesting that OCTs play a major role in the overall hepatic uptake of pazopanib in mice. In human embryonic kidney cell line HEK293 cells stably transfected with human OCT1, pazopanib uptake was significantly higher than that in vector-transfected cells. Moreover, pazopanib uptake by OCT1 became saturated and was inhibited by TPeA, but not by CsA, confirming that pazopanib is also a substrate of human OCT1. Importantly, OCT1-mediated uptake of a typical OCT1 substrate metformin was inhibited by pazopanib with an IC50 value of 0.253 µM, indicating that pazopanib has the potential for clinically relevant inhibition of human OCT1. Finally, pazopanib was taken up by cryopreserved human pooled hepatocytes in a time-dependent manner, and this uptake was largely reduced by TPeA but only partially reduced by CsA. Thus, the present findings suggest that OCT1 is responsible for hepatocellular uptake of pazopanib.

Graphene nanoparticles as osteoinductive and osteoconductive platform for stem cell and bone regeneration.

The potential of graphene-based nanoparticles (GNPs) has recently gained significant attention in biomedicine, especially in tissue engineering. In this study, we investigated the osteoinductive and osteoconductive effects of low oxygen content graphene (LOG) nanoparticles on adult mesenchymal stem cells (MSCs) in vitro and in vivo. We showed that adult goat MSCs were viable in the presence of 0.1 mg/mL LOG and retained their stem cell properties. A 3D scaffold made from agarose was used to encapsulate MSCs and LOG nanoparticles. Scanning electron microscopy demonstrated the cell morphology and adherence of MSCs to LOG in the 3D form. The LOG and MSCs in the 3D scaffold were xenogenically implanted into a rat unicortical tibial bone defect. The combination of MSCs and LOG nanoparticles resulted in improved active bone formation and increased mineralization. These results strengthen the applicability of LOG nanoparticles as an adjunct treatment for bone tissue engineering.

Accelerating wound healing: Unveiling synergistic effects of P25/SWCNT/Ag and P25/rGO/Ag nanocomposites within PRP-gelatin scaffold, highlighting the synergistic antimicrobial activity.

Wound healing is a multifaceted biological process requiring innovative strategies to enhance efficiency and counter infections. In this groundbreaking study, we investigate the regenerative potential of platelet-rich plasma (PRP) integrated into a gelatin (GLT) scaffold along with nanocomposites of titanium dioxide (TiO2) (P25)/single-walled carbon nanotubes (SWCNTs)/Ag and P25/reduced graphene oxide (rGO)/Ag. Incorporating these advanced materials into the PRP/GLT delivery system aims to optimize the controlled release of growth factors (GFs) and leverage the exceptional properties of nanomaterials for enhanced tissue repair and wound healing outcomes. Antioxidant activity assessment using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity reveals the superior performance of P25/SWCNTs/Ag compared to P25/rGO/Ag. Their synergistic effects are evaluated in conjunction with antibacterial and antifungal antibiotics. Furthermore, the wound healing potential of P25/SWCNTs/Ag and P25/rGO/Ag, combined with PRP/GLT, is examined. Notably, both nanocomposites exhibit promising synergistic effects with gentamicin and fluconazole against pathogenic strains. Significantly, the inclusion of non-activated PRP substantially augments the wound healing efficacy of P25/SWCNTs/Ag on days 3 (p < 0.01) and 15 (p < 0.05). These findings pave the way for advanced wound dressing and therapeutic interventions, capitalizing on the synergistic effects of PRP and nanomaterials, thus ultimately benefiting patients and advancing regenerative medicine.

Gelatin Loaded Titanium Dioxide and Silver Oxide Nanoparticles: Implication for Skin Tissue Regeneration.

Treatment of burn wounds has many requirements to ensure wound closure with healthy tissue, increased vascularization, guarantee edema resolution, and control bacterial infection. We propose that titanium oxide (TiO2) nanoparticles (NPs) will be more efficient than silver dioxide (Ag2O) in the treatment of burn wounds. Herein, gelatin loaded NPs (GLT-NPs) were evaluated for their efficacy to regenerate second-degree burn wound in rabbit skin. TEM results revealed that the average particle sizes were ⁓ 7.5 and 17 nm for Ag2O and TiO2 NPs, respectively. The results of the in vivo application of GLT-NPs on burn wound in the rabbit revealed that both Ag2O and TiO2 NPs were efficient than the control none treated (CTRL) and GLT group. In terms of the healing rate, the GLT-TiO2 did not show any significant difference than GLT-Ag2O (99.57% vs. 99.85%, p = 0.2). Meanwhile, the healing rate was significantly higher in both NPs' treated groups than CTRL (94.16%, p < 0.01) and GLT group (95.07%, p < 0.05). Also, the histological analysis using H&E staining showed re-epithelization, less edema, and enhanced vascularization in both GLT-NPs than CTRL and GLT groups. Furthermore, immunohistochemical analysis of TGF-ß1 and α-SMA revealed significantly a higher expression in both GLT-NPs groups than CTRL and GLT groups at weeks 1 and 2 (p < 0.05). Interestingly, TGF-ß1 and α-SMA were substantially higher in GLT- TiO2 than GLT-Ag2O at weeks 1 and 2 (p < 0.05), but the expression was not significant at week 3. In conclusion, GLT-NPs showed higher regenerative capacity and enhanced the healing quality after burn wound compared to CTRL and GLT. Graphical abstract.

Impact of the source and serial passaging of goat mesenchymal stem cells on osteogenic differentiation potential: implications for bone tissue engineering.

BACKGROUND: Adult mesenchymal stem cells (MSCs) can be conveniently sampled from bone marrow, peripheral blood, muscle, adipose and connective tissue, harvested from various species, including, rodents, dogs, cats, horses, sheep, goats and human beings. The MSCs isolated from adult tissues vary in their morphological and functional properties. These variations are further complicated when cells are expanded by passaging in culture. These differences and changes in MSCs must be considered prior to their application in the clinic or in a basic research study. Goats are commonly used as animal models for bone tissue engineering to test the potential of stem cells for bone regeneration. As a result, goat MSCs isolated from bone marrow or adipose tissue should be evaluated using in vitro assays, prior to their application in a tissue engineering project. RESULTS: In this study, we compared the stem cell properties of MSCs isolated from goat bone marrow and adipose tissue. We used quantitative and qualitative assays with a focus on osteogenesis, including, colony forming unit, rate of cell proliferation, tri-lineage differentiation and expression profiling of key signal transduction proteins to compare MSCs from low and high passages. Primary cultures generated from each source displayed the stem cell characteristics, with variations in their osteogenic potentials. Most importantly, low passaged bone marrow MSCs displayed a significantly higher and superior osteogenic potential, and hence, will be the preferred choice for bone tissue engineering in future in vivo experiments. In the bone marrow MSCs, this process is potentially mediated by the p38 MAPK pathway. On the other hand, osteogenic differentiation in the adipose tissue MSCs may involve the p44/42 MAPK pathway. CONCLUSIONS: Based on these data, we can conclude that bone marrow and fat-derived MSCs undergo osteogenesis via two distinct signaling pathways. Even though the bone marrow MSCs are the preferred source for bone tissue engineering, the adipose tissue MSCs are an attractive alternative source and undergo osteo-differentiation differently from the bone marrow MSCs and hence, might require a cell-based enhancer/inducer to improve their osteogenic regenerative capacity.