The laboratories of Drs. Jene Choi and Chong Jai Kim from the University of Ulsan College of Medicine in Seoul, South Korea have collaboratively shown that the therapeutic quality of umbilical cord mesenchymal stem cells is profoundly affected by gestational diabetes. Their work was published in a recent issue of the journal Stem Cells and Development and has profound implications for regenerative medicine.
Choi and Kim and their coworkers collected umbilical cords from mothers who had been given birth by Cesarian section and had also been diagnosed with gestational diabetes and mothers who had also just given birth by Cesarian section and showed normal blood sugar control. These umbilical cord tissues were processed and the mesenchymal stem cells from the cord tissue were isolated and cultured. These cells were grown and then subjected to a rather extensive battery of tests. These tests were a reflection of the ability of these to perform in regenerative treatments.
First umbilical cord mesenchymal stem cells (UCMSCs) from mothers with gestational diabetes (GD) did not grow as well as UCMSCs from mother who did not have GD. As you can see in the graphs below, these are not small growth differences. The UCMSCs from non-GD mothers (on the left) grow substantially better than those from GD mothers. This result is also consistent for different cell lines. This also means that transplanted cells would not grow very well if they were used for therapeutic purposes.
Umbilical cord mesenchymal stromal cells (UC-MSCs) derived from gestational diabetes mellitus (GDM) patients exhibit retarded growth proliferation. The growth of 7.5×103 UC-MSCs isolated from patients with normal pregnancies (A) and GDM (B) was monitored over a period of 12 days. GDM-UC-MSCs consistently showed decreased proliferation compared with normal pregnant women (N-UC-MSCs). Points represent the mean values from three independent experiments; bars denote standard deviation (SD).
Secondly, UCMSCs from GD mothers showed a greater tendency to undergo premature senescence. When MSCs are grown in culture, they usually grow rather well for several days and then the cells go to sleep and they stop growing. This is called culture senescence and it is due to intrinsic properties of the cells. When the cells go into senescence tends to be a cell line-specific property, but one thing is certain; the sooner cells become senescent, the few cells they will generate in culture. The UCMSCs from GD mothers go into senescence early and easily and this is one of the reasons they grow so poorly relative to normal cells – because they are running to their beds to take a nap (so to speak). Such cells are usually not good candidates for regenerative medicine.
Third, UCMSCs from GD mothers show poor lineage-specific differentiation. MSCs have the ability to differentiate into fat cells, bone cells, and cartilage cells if particular well-established protocols are used. However, UCMSCs from GD mothers showed inefficient differentiation and that is one of the things that MSCs must do if they are to repair bone or cartilage problems or if they are to help make smooth muscle for new blood vessels formation.
Stem cell differentiation potentials are largely different between normal and GDM-affected UC-MSCs. Three different cell lines of normal and GDM-affected pregnancies were cultured in a control medium or induction medium for 5 days. Upregulation of the expression of the adipogenic-specific gene PPARγ (A) and the osteogenic genes alkaline phosphatase (ALP) (B), osteocalcin (OC) (C), and collagen type 1 alpha 1 (Col1α1) (D) was evaluated by real-time RT-PCR and normalized to GAPDH. All assays were performed in triplicate; bars denote SD (*P<0.05).
The figure above shows the disparity between these established UCMSC cell lines. The dark, solid bars indicate non-induced cells that were grown in normal culture media, and the striped bars are cells grown in media that designed to induce the differentiation of these cells into either bone, fat, or cartilage cells. The cell lines with “N” in their name are from non-GD mothers and those with “D” in their designations are from GD mothers. These assays are for genes known to be strongly induced when cells begin to differentiate into fat (PPARgamma), bone (ALP or osteocalcin or collagen 1 alpha 1). As you can clearly see, the Ns outdo the Ds every time.
Finally, when the mitochondria, the compartments in cells that generate energy, from these two cell populations were examined it was exceedingly clear that UCMSCs from GD mothers had mitochondria that were abnormal and did not make every very well. Mitochondria from UCMSCs taken from GD mothers showed decreased expression of the energy-making components. Thus the energy-making pathways in these cell compartments were sub-par from a structural perspective. Functional assays for mitochondria showed that mitochondria from UCMSCs from GD mothers consistently underperformed those from UCMSCs taken from non-GD mothers. Also, when markers of mitochondrial dysfunction were measured (reactive oxygen species and indicators of mitochondrial damage from reactive oxygen species), such markers were consistently higher in mitochondria from UCMSCs from GD mothers relative to those from non-GD mothers. This shows that the energy-making or powerhouses of the cells are dysfunctional in UCMSCs from GD mothers. Without the ability to properly make energy from food molecules, the cells have a diminished capacity to heal damaged tissues and organs.
Several studies have established a positive link between mitochondrial dysfunction and accelerated aging. Therefore, these cells, because they have more extensive indications of mitochondrial damage, may show profound accumulation of mitochondrial damage and accelerated aging.
In summary, this study shows that integral biological properties of human UC-MSCs differ according to obstetrical conditions. These data also stress the importance of maternal–fetal conditions in biological studies of hUC-MSCs and the development of future therapeutic strategies using hUC-MSCs.