Adipose tissue-derived mesenchymal stem cells are more potent suppressors of dendritic cells differentiation compared to bone marrow-derived mesenchymal stem cells.

Both mesenchymal stem cells (MSCs) and dendritic cells (DCs) are engaged in the regulation of the immune response parallel to their numerous functions. The main objective of this study was to compare the effects of mesenchymal stem cells isolated from human adipose tissue or human bone marrow on the expression of specific cell surface markers as well as the secretion of some cytokines by monocyte-derived dendritic cells. The set of methods used includes cell cultures, magnetic beads isolation of cells, flow cytometry, ELISA and proteome profiler kit assays. The results obtained show that MSCs isolated from human adipose tissue are more potent immunomodulators of differentiation of human DCs in comparison to the bone marrow-derived MSCs. In both cases the percentages of CD14+ cells were increased in co-cultures of MSCs and DCs and at the same time down-regulated the expression of CD80, CD86 and CD83 as in all experiments the effect of adipose tissue MSCs was stronger. Similarly, the secretion of IL-10 by dendritic cells was up-regulated in co-cultures of MSCs and dendritic cells and the effect was stronger when adipose tissue-derived MSCs were used. Taken together all results presented reveal the higher potential of the adipose tissue-derived MSCs to inhibit the differentiation and expression of functionally important co-stimulatory molecules on the surface of monocyte-derived dendritic cells than the bone marrow-derived MSCs.

HLA-G expression is up-regulated by progesterone in mesenchymal stem cells.

PROBLEM: Maternal immune response to fetal tissues is modified in such way that it favors the development of pregnancy. Human leukocyte antigen (HLA)-G, progesterone and mesenchymal stem cells (MSCs) have been identified as potent immunomodulatory agents in different experimental systems and the interactions between these three factors are studies in this paper. METHOD OF STUDY: Human MSCs are isolated from human adipose tissue, bone marrow and decidua are cultured in the presence of progesterone and the expression of HLA-G is followed-up at protein and mRNA levels. RESULTS: The MSCs cultured in the presence of progesterone express increased levels of both cell surface and cytoplasmic HLA-G when compared with the control MSCs. CONCLUSION: Progesterone up-regulates the expression by MSCs of HLA-G which is a major player in maintenance of the immune balance between the mother and the fetus. MSCs are newly detected targets of progesterone with well documented immunomodulatory activity.

Revision total hip arthroplasty with cementing technique--five-year results.

AIM: To investigate the result of cemented revision hip arthroplasty. MATERIAL AND METHODS: Twenty-one revision hip arthroplasties for aseptic loosening with cementing technique during the period 1990-2002 were followed-up. There were 12 women and 9 men with mean age at the time of revision 61 years (33 to 76 years). The mean follow-up for the group was 5.2 years (range, 2 to 13 years). The clinical evaluation was performed with the Harris hip score. Implant survival, pain, function and complications were recorded. Plain radiographs were reviewed and the hips were graded for osteolysis and loosening. Wear of the polyethylene was measured. RESULTS: No component was exchanged. Three of the acetabular and three of the stem components in the hips with early cementing technique were loose. In two patients three surgeries were performed for trochanteric problems and persistent pain. Clinical result and bone defects preoperatively as well as wear and osteolysis correlated significantly. DISCUSSION: Stable fixation of the prosthesis is of paramount importance in revision surgery. In cases with severe bone defects stable interface is difficult to be achieved. This may change stress distribution and subsequently lead to loosening. CONCLUSION: Better preoperative planning and improvement in cementing technique may improve results. Other revision techniques may be considered in cases with severe bone deficiencies.