Cell-based regenerative medicine therapies are now frequently tested in clinical trials. In many conditions, cell therapies are administered systemically, but there is little understanding of their fate, and adverse events are often under-reported. Currently, it is only possible to assess safety and fate of cell therapies in preclinical studies, specifically by monitoring animals longitudinally using multi-modal imaging approaches. Here, using a suite of in vivo imaging modalities to explore the fate of a range of human and murine cells, we investigate how route of administration, cell type and host immune status affect the fate of administered cells. We applied a unique imaging platform combining bioluminescence, optoacoustic and magnetic resonance imaging modalities to assess the safety of different human and murine cell types by following their biodistribution and persistence in mice following administration into the venous or arterial system. Longitudinal imaging analyses (i) suggested that the intra-arterial route may be more hazardous than intravenous administration for certain cell types, (ii) revealed that the potential of a mouse mesenchymal stem/stromal cell (MSC) line to form tumours depended on administration route and mouse strain and (iii) indicated that clinically tested human umbilical cord (hUC)-derived MSCs can transiently and unexpectedly proliferate when administered intravenously to mice. In order to perform an adequate safety assessment of potential cell-based therapies, a thorough understanding of cell biodistribution and fate post administration is required. The non-invasive imaging platform used here can expose not only the general organ distribution of these therapies, but also a detailed view of their presence within different organs and, importantly, tumourigenic potential. Our observation that the hUC-MSCs but not the human bone marrow (hBM)-derived MSCs persisted for a period in some animals suggests that therapies with these cells should proceed with caution.

The aim of this work was to isolate, for the first time, progenitor‐like cells from the epithelial (AECs) and mesenchymal (AMCs) portions of the horse amniotic membrane, and to define the biological properties of these cells. AECs displayed polygonal epithelial morphology, while AMCs were fibroblast‐like. Usually, six to eight passages were reached before proliferation decreased, with 13.08 and 26.5 cell population doublings attained after 31 days for AECs and AMCs, respectively. Immunocytochemical studies performed at passage 3 (P3) showed that both cell populations were positive for the expression of specific embryonic markers (TRA‐1‐60, SSEA‐3, SSEA‐4 and Oct‐4). Meanwhile, RT–PCR performed at P1 and P5 showed expression of mesenchymal stem/stromal cell markers (CD29, CD105, CD44 and CD166) with negativity for CD34 at P1, although this marker began to be expressed by P5. The cells also expressed MHC‐I at both P1 and P5, but lacked MHC‐II expression at P1. Both AECs and AMCs demonstrated high plasticity, differentiating in vitro toward the osteogenic, adipogenic, chondrogenic and neurogenic lineages. Equine amnion‐\derived cells could also be frozen and recovered without loss of their functional integrity in terms of morphology, presence of specific stemness markers and differentiation ability, although the renewal capacity was lower than that observed for freshly isolated cells. To investigate potential therapeutic effects and cell tolerance in vivo, horse amnion‐derived cells were allogeneically injected into three horses with tendon injuries, resulting in a quick reduction in tendon size and ultrasonographic cross‐sectional area measurements. These results suggest that horse amnion‐derived cells may be useful for cell therapy applications. Copyright © 2011 John Wiley & Sons, Ltd.

Biliary fibrosis and resultant cirrhosis are among the most common outcomes of chronic liver diseases. Currently, liver transplantation remains the only effective treatment. In seeking alternative therapeutic approaches, we focused on the potential use of the human amniotic membrane (AM). Indeed, AM has gained increasing importance for its antiscarring, anti-inflammatory, and wound-healing properties, as well as for the multipotent differentiation ability and immunomodulatory features of AM-derived cells. Intriguingly, we have recently demonstrated that placenta-derived cells reduce lung fibrosis in bleomycin-treated mice, and that AM patches reduce postischemic cardiac injury in rats. Hence, we have now investigated the effects of human AM on biliary fibrosis induced in rats through the bile duct ligation (BDL) procedure. A fragment of human AM was applied onto the liver surface after BDL and the effects on fibrosis establishment and progression were evaluated at different time points in comparison with fibrosis progression in control BDL rats. The degree of liver fibrosis was first assessed by the semiquantitative Knodell scoring system and, thereafter, by digital image morphometric analysis to quantify the area occupied by ductular reaction, activated myofibroblasts, and collagen deposition. We demonstrated a significant reduction in the severity of BDL-induced fibrosis in AM-treated rats. Indeed, while fibrosis progressed rapidly in control BDL rats, leading to cirrhosis within 6 weeks, AM-treated rats showed confined fibrosis at the portal/periportal area with no signs of cirrhosis, and a reduction in collagen deposition to about 50% of levels observed in control BDL rats. In addition, the AM was able to significantly slow the gradual progression of the ductular reaction and reduce, at all time points, the area occupied by activated myofibroblasts. These findings suggest that human AM, when applied as a patch onto the liver surface, might inhibit fibrosis progression in BDL-injured livers, and could protect against hepatic damage associated with fibrotic degeneration.

We have demonstrated recently that transplantation of placental membrane-derived cells reduces bleomycin-induced lung fibrosis in mice, despite a limited presence of transplanted cells in host lungs. Because placenta-derived cells are known to release factors with potential immunomodulatory and trophic activities, we hypothesized that transplanted cells may promote lung tissue repair via paracrine-acting molecules. To test this hypothesis, we examined whether administration of conditioned medium (CM) generated from human amniotic mesenchymal tissue cells (AMTC) was able to reduce lung fibrosis in this same animal model. Bleomycin-challenged mice were either treated with AMTC-CM or control medium, or were left untreated (Bleo group). After 9 and 14 days, the distribution and severity of lung fibrosis were assessed histologically with a scoring system. Collagen deposition was also evaluated by quantitative image analysis. At day 14, lung fibrosis scores in AMTC-CM-treated mice were significantly lower (P < 0.05) compared with mice of the Bleo group, in terms of fibrosis distribution [1.0 (interquartile range, IQR 0.9) versus 3.0 (IQR 1.8)], fibroblast proliferation [0.8 (IQR 0.4) versus 1.6 (IQR 1.0)], collagen deposition [1.4 (IQR 0.5) versus 2.0 (IQR 1.2)] and alveolar obliteration [2.3 (IQR 0.8) versus 3.2 (IQR 0.5)]. No differences were observed between mice of the Bleo group and mice treated with control medium. Quantitative analysis of collagen deposition confirmed these findings. Importantly, AMTC-CM treatment significantly reduced the fibrosis progression between the two observation time-points. This pilot study supports the notion that AMTC exert anti-fibrotic effects through release of yet unknown soluble factors.

Veterinary pathologists commonly encounter lesions of blunt trauma. The development of lesions is affected by the object’s mass, velocity, size, shape, and angle of impact and by the plasticity and mobility of the impacted organ. Scrape, impact, and pattern abrasions cause localized epidermal loss and sometimes broken hairs and implanted foreign material. Contusions are best identified after reflecting the skin, and must be differentiated from coagulopathies and livor mortis. Lacerations—traumatic tissue tears—may have irregular margins, bridging by more resilient tissue, deviation of the wound tail, crushed hairs, and unilateral abrasion. Hanging or choking can cause circumferential cervical abrasions, contusions and rupture of hairs, hyoid bone fractures, and congestion of the head. Other special forms of blunt trauma include fractured nails, pressure sores, and dog bites. Ocular blunt trauma causes extraocular and intraocular hemorrhages, proptosis, or retinal detachment. The thoracic viscera are relatively protected from blunt trauma but may develop hemorrhages in intercostal muscles, rib fractures, pulmonary or cardiac contusions or lacerations with subsequent hemothorax, pneumothorax, or cardiac arrhythmia. The abdominal wall is resilient and moveable, yet the liver and spleen are susceptible to traumatic laceration or rupture. Whereas extravasation of blood can occur after death, evidence of vital injury includes leukocyte infiltration, erythrophagocytosis, hemosiderin, reparative lesions of fibroblast proliferation, myocyte regeneration in muscle, and callus formation in bone. Understanding these processes aids in the diagnosis of blunt force trauma including estimation of the age of resulting injuries.