Evaluation of ultrasmall superparamagnetic iron oxide contrast agent labeling of equine cord blood and bone marrow mesenchymal stromal cells.

OBJECTIVE: To evaluate the efficacy and effects of labeling equine umbilical cord blood (UCB)- and bone marrow (BM)-derived multipotent mesenchymal stromal cells (MSCs) with an ultrasmall superparamagnetic iron oxide (SPIO) contrast agent and the detection of labeled MSCs by use of MRI. SAMPLE: UCB MSCs from placental tissues of 5 foals and BM MSCs from 5 horses. PROCEDURES: UCB and BM MSC cultures were seeded in duplicate (5,000 cells/cm(2)). One duplicate was incubated with SPIO (50 µg/mL); the other was processed identically, but without SPIO. Mesenchymal stromal cells were expanded in triplicates for 5 passages and assessed for viability and proliferative capacity, labeling efficacy, and labeled cell proportion. For MRI detection, 5 × 10(6) labeled BM MSCs from passage 1 or 2 were injected into a collagenase-induced superficial digital flexor tendon defect of an equine cadaveric forelimb from 2 horses. RESULTS: For passages 1, 2, and 3, labeling efficacy and cell proportion for UCB MSCs (99.6% [range, 98.8% to 99.9%], 16.6% [range, 6.5% to 36.1%], and 1.0% [range, 0.4% to 2.8%], respectively) were significantly higher than for BM MSCs (99.2% [range, 97.8% to 99.7%], 4.5% [range, 1.6% to 11.8%], and 0.2% [range, 0.1% to 0.6%], respectively). Labeling was not detectable after passage 3. Viability of MSCs was not affected, but cell doubling time increased in labeled MSCs, compared with that of unlabeled MSCs. On MRI 3-D T2*-weighted fast gradient echo sequences, decreased signal intensity was observed for BM passage 1 MSCs. CONCLUSIONS AND CLINICAL RELEVANCE: Equine UCB and BM MSCs were labeled with SPIO at high efficiencies.

Effect of unfocused extracorporeal shock wave therapy on growth factor gene expression in wounds and intact skin of horses.

OBJECTIVE: To compare the effect of extracorporeal shock wave therapy (ESWT) on expression of fibroblast growth factor-7 (FGF-7), transforming growth factor-ß1 (TGF-ß1), insulin-like growth factor-1 (IGF-1), platelet-derived growth factor-A (PDGF), and vascular endothelial growth factor-A (VEGF) in skin with surgically created skin wounds and intact skin in horses. ANIMALS: 14 healthy horses. PROCEDURE: 8 horses were treated with ESWT at 6 locations along the neck at 36, 24, 12, 6, 2, or 1 hour prior to collection of full-thickness biopsy specimens from each location; a control specimen was collected from a sham-treated location. In 6 horses, 5 full-thickness wounds were created in each forelimb. Wounds in 1 forelimb/horse received ESWT immediately after creation and subsequently on days 7, 14, and 21; wounds in the contralateral forelimb remained untreated. Biopsy specimens were collected from 1 wound on each forelimb on days 7, 14, 21, 28, and 35. Expression levels of FGF-7, TGF-ß1, IGF-1, PDGF, and VEGF were assessed in tissue samples from the horses' necks and forelimbs. RESULTS: In surgically created wounds, ESWT treatment was associated with reduced TGF-ß1 expression, compared with expression in control wounds, during the entire study period. At 28 days following wound creation, IGF-1 expression was significantly increased for treated and untreated wounds, compared with findings on days 7, 14, 21, and 35. There was no significant effect of treatment on FGF-7, TGF-ß1, IGF-1, PDGF, or VEGF expression in intact skin. CONCLUSIONS AND CLINICAL RELEVANCE: Intervention with ESWT to suppress TGF-ß1 may decrease granulation tissue production, resulting in improved wound healing on the distal portion of horses' limbs.