Amniotic fluid stem cells and their application in cell-based tissue regeneration

Advances in stem cell biotechnology hold great promise in the field of tissue engineering and regenerative medicine. Of interest are marrow mesenchymal stem cells [MSCs], embryonic stem cells [ESCs], and induced pluripotent stem cells [iPSCs]. In addition, amniotic fluid stem cells [AFSCs] have attracted attention as a viable choice following the search for an alternative stem cell source. Investigators are interested in these cells because they come from the amniotic fluid that is routinely discarded after birth. There have been multiple investigations conducted worldwide in an attempt to better understand AF-SCs in terms of their potential use in regenerative medicine. In this review we give a brief introduction of amniotic fluid followed by a description of the cells present within this fluid. Their history related to stem cell discovery in the amniotic fluid as well as the main characteristics of AF-SCs are discussed. Finally, we elaborate on the potential for these cells to promote regeneration of various tissue defects, including fetal tissue, the nervous system, heart, lungs, kidneys, bones, and cartilage.

Intra-articular injection of autologous mesenchymal stem cells in six patients with knee osteoarthritis

Osteoarthritis [OA] is a progressive disorder of the joints caused by gradual loss of articular cartilage, which naturally possesses a limited regenerative capacity. In the present study, the potential of intra-articular injection of mesenchymal stem cells [MSCs] has been evaluated in six osteoarthritic patients. Six female volunteers, average age of 54.56 years, with radiologic evidence of knee OA that required joint replacement surgery were selected for this study. About 50 ml bone marrow was aspirated from each patient and taken to the cell laboratory, where MSCs were isolated and characterized in terms of some surface markers. About 20-24x106 passaged-2 cells were prepared and tested for microbial contamination prior to intra-articular injection. During a one-year follow-up period, we found no local or systemic adverse events. All patients were partly satisfied with the results of the study. Pain, functional status of the knee, and walking distance tended to be improved up to six months post-injection, after which pain appeared to be slightly increased and patients' walking abilities slightly decreased. Comparison of magnetic resonance images [MRI] at baseline and six months post-stem cell injection displayed an increase in cartilage thickness, extension of the repair tissue over the subchondral bone and a considerable decrease in the size of edematous subchondral patches in three out of six patients. The results indicated satisfactory effects of intra-articular injection of MSCs in patients with knee OA

Mesenchymal stem cells from murine amniotic fluid as a model for preclinical investigation

Despite the suitability of a mouse model for preclinical investigations; little is known regarding mesenchymal stem cells derived from murine amniotic fluid. This is the subject of the present study. Amniotic fluid was collected from NMRI mice during the second weeks of pregnancy and plated. The cells that adhered to the culture surfaces were propagated with three successive subcultures and then characterized. To determine the differentiation potential, the cells were cultivated under osteogenic, adipogenic, and chondrogenic conditions, and followed by specific staining and RT-PCR analysis for differentiation. The proliferative potential of the cells were with clonogenic assays, population doubling time and number and by growth curve plotting. Cellular aging was investigated with the senescence-associated beta-galactosidase staining method. The amniotic fluid primary cell culture was composed of round flattened and fibroblastic cells. The latter dominated the culture after several passages. Successful tripotent differentiation of the isolated cells into bone, cartilage and adipose cells were indicative of their mesenchymal stem cells nature. The isolated cells appeared to be relatively proliferative cells as confirmed by the population doubling time value which was equal to about 69 hours. Furthermore, the cells were relatively clonogenic and they tended to initate proliferation immediately after plating [there was no lag phase in their growth curve]. Beta- galactosidase positive cells were first observed at passage 3 and increased in number with subsequent passagers. Collectively it was concluded that murine amniotic fluid contained mesenchymal stem cells with relatively high proliferation property and typical tripotent differentiation potential