B- and T-cell lymphocytes and other immune cell infiltration in the duodenal and rectal mucosa of severe asthmatic horses.

OBJECTIVE: The objectives of this study were to quantify lymphocytes and eosinophils in the mucosa of the duodenum and rectum in asthmatic horses. ANIMALS: 8 healthy and 10 asthmatic horses. PROCEDURES: Asthmatic horses were evaluated in a symptomatic (after 6 weeks of exposure to moldy hay) and asymptomatic status (3 and 7 months after being fed alfalfa pellets [n = 4] or treated with inhaled fluticasone [6]). Duodenal and rectal biopsies were endoscopically (n = 4 to 6) taken in each horse. Eosinophils were counted on slides stained with hematoxylin, eosin, phloxine, and saffron, and immunohistochemistry was used to evaluate T and B lymphocytes using CD3 and CD20, respectively. RESULTS: The duodenal and rectal epithelium of asthmatic and control horses contained exclusively T lymphocytes (CD3). Symptomatic asthmatic horses, compared to controls, had a significantly higher number of T lymphocytes (CD3) in the duodenal epithelium (P = .016) and the adjacent lamina propria of the villi (P = .04). Compared to symptomatic asthmatic horses, the fluticasone-treated group had significantly fewer T lymphocytes in the total lamina propria of the rectal mucosa (P < .01). CLINICAL RELEVANCE: Taken together, these results suggest that asthmatic horses have greater infiltration of T lymphocytes in the duodenal and rectal mucosa, indicating a certain degree of inflammation, which could be due to a systemic inflammatory effect and/or a local effect of ingested hay allergens in asthmatic horses. Systemic markers of inflammation have not been investigated to better qualify if the infiltration noted is due to a local and/or systemic effect.

Impact of microcarrier concentration on mesenchymal stem cell growth and death: Experiments and modeling.

Mesenchymal stem cell (MSC) products are promising therapeutic candidates to treat a wide range of pathologies. The successful commercialization of these cell therapies will, however, depend on the development of reproducible cell production processes. For this, using microcarriers as growth supports within controlled conditions may be a viable process option. Although increasing microcarrier concentration may be associated with greater productivity due to the increased available culture surface, additional friction or shocks between microcarriers are likely to lead to undesired cell death. However, data detailing the impact of microcarrier collisions on MSC growth remains scarce. The following work demonstrates that MSC growth on microcarriers is greatly influenced by particle concentration even when little impact is observed on the apparent growth rate. It is suggested that the apparent growth rate may result in an equilibrium between growth and death kinetics which are independently affected by particle concentration and that certain MSC quality attributes may be progressively degraded in parallel. In addition, the theoretical reduction of the MSC growth rate was modeled according to the ratio between the average interparticle distance and the Kolmogorov scale. This study is an original contribution toward understanding the hydrodynamic effects in microcarrier-based stem cell cultures.

Impact of the type of microcarrier and agitation modes on the expansion performances of mesenchymal stem cells derived from umbilical cord.

The present study proposed to compare the impact of agitation mode (static, orbital, and mechanical) on the culture of mesenchymal stem cells extracted from the Wharton's jelly of umbilical cords (WJ-MSC), in a clinical grade culture medium, using human platelet lysate and different xeno-free microcarriers. Attachment, expansion, and detachment performances were characterized by a new dedicated tool of microscopic image posttreatment, allowing an in situ cell counting without detachment step. Results showed that performances in static mode were not necessarily representative of those obtained in dynamic mode. Moreover, impacts on nutrient consumptions and metabolite productions were identified, such as a higher glutamine consumption when Cytodex-1 microcarriers were used. The detachment strategy used was relatively efficient for Star-Plus, Plastic-Plus, and Hillex II, but not sufficient for Cytodex-1. Despite Cytodex-1 presented promising attachment and expansion performances, Star-Plus and Plastic-Plus showed a better compromise, respectively, for the orbital and the mechanical agitation modes.