Mesenchymal stem cells reverse bone XXXX following injury and stress.

@entity4306 @entity7420 @entity358 @entity35 @entity236 @entity734 @entity130
BACKGROUND: Bone marrow (BM) dysfunction following experimental @entity358 ( @entity358 ) resolves in 7 days; however, if followed by chronic stress (CS) following, @entity236 is persistent. Mesenchymal stem cells (MSCs) have protective immunomodulatory effects. We hypothesize that MSC can protect the BM against the deleterious effect of CS following @entity358 . METHODS: Male @entity35 (n = 6-7 per group) underwent @entity358 or @entity358 /CS    MSC injection. CS consisted of a daily 2-hour period of restraint with repositioning and alarming every 30 minutes to prevent @entity734 . A single intravenous dose of 5 * 10 MSCs was given within 10 minutes following @entity358 . Animals were sacrificed at Day 7, and peripheral blood (PB) and BM were collected. Flow cytometry was used to assess hematopoietic progenitor cells (HPCs) mobilized to PB. Plasma @entity7420 ( @entity7420 ) levels were measured by enzyme-linked immunosorbent assay. BM cellularity and growth of BM @entity4306 colonies (colony-forming unit-erythroid [CFU-E], burst-forming unit-erythroid [BFU-E], colony-forming unit-granulocyte, erythrocyte, monocyte, megakaryocyte [CFU-GEMM]) were also evaluated. RESULTS: As previously reported, the addition of CS to @entity358 resulted in a 32% decrease in BM cellularity; significant decreases in CFU-GEMM, BFU-E, and CFU-E; and marked increase in @entity4306 in the PB as compared with the naive animals. The addition of MSC to @entity358 /CS resulted in a 22% increase in BM cellularity and significant increases in CFU-GEMM, BFU-E, and CFU-E cultured from the BM. MSCs additionally reduced plasma @entity7420 , prevented prolonged mobilization of @entity4306 to PB, and restored colony growth to naive levels. CONCLUSION: CS following @entity358 results in persistent @entity236 manifested by a significant decrease in cellularity, @entity4306 colony growth, and increased @entity7420 levels and @entity4306 mobilization to the PB at 7 days following injury. The addition of a single dose of MSCs following acute @entity130 reverses the deleterious effects of CS on BM function. Further study is warranted to better understand the mechanisms behind MSC-mediated protection of BM function in the setting of CS.
