Hyun Ok Kim

Mesenchymal stem cells (MSCs) are clinically useful due to their capacity for self-renewal, their immunomodulatory properties and tissue regenerative potential. These cells can be isolated from various tissues and exhibit different potential for clinical applications according to their origin, and thus comparative studies on MSCs from different tissues are essential. In this study, we investigated the immunophenotype, proliferative potential, multilineage differentiation and immunomodulatory capacity of MSCs derived from different tissue sources, namely bone marrow, adipose tissue, the placenta and umbilical cord blood. The gene expression profiles of stemness-related genes [octamer-binding transcription factor 4 (OCT4), sex determining region Y-box (SOX)2, MYC, Krüppel-like factor 4 (KLF4), NANOG, LIN28 and REX1] and lineage‑related and differentiation stage-related genes [B4GALNT1 (GM2/GS2 synthase), inhibin, beta A (INHBA), distal-less homeobox 5 (DLX5), runt-related transcription factor 2 (RUNX2), proliferator‑activated receptor gamma (PPARG), CCAAT/enhancer-binding protein alpha (C/EBPA), bone morphogenetic protein 7 (BMP7) and SOX9] were compared using RT-PCR. No significant differences in growth rate, colony-forming efficiency and immunophenotype were observed. Our results demonstrated that MSCs derived from bone marrow and adipose tissue shared not only in vitro tri-lineage differentiation potential, but also gene expression profiles. While there was considerable inter-donor variation in DLX5 expression between MSCs derived from different tissues, its expression appears to be associated with the osteogenic potential of MSCs. Bone marrow-derived MSCs (BM-MSCs) significantly inhibited allogeneic T cell proliferation possibly via the high levels of the immunosuppressive cytokines, IL10 and TGFB1. Although MSCs derived from different tissues and fibroblasts share many characteristics, some of the marker genes, such as B4GALNT1 and DLX5 may be useful for the characterization of MSCs derived from different tissue sources. Collectively, our results suggest that, based on their tri-lineage differentiation potential and immunomodulatory effects, BM-MSCs and adipose tissue-derived MSCs (A-MSCs) represent the optimal stem cell source for tissue engineering and regenerative medicine.

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 not yet has established its treatment, but convalescent plasma has been expected to increase survival rates as in the case with other emerging viral infections. We describe two cases of COVID-19 treated with convalescent plasma infusion. Both patients presented severe pneumonia with acute respiratory distress syndrome and showed a favorable outcome after the use of convalescent plasma in addition to systemic corticosteroid. To our knowledge, this is the first report of the use of convalescent plasma therapy for COVID-19 in Korea.

Parkinson's disease (PD) is a common, progressive neurodegenerative disorder caused by the loss of dopaminergic neurons in the substantia nigra (SN). Numerous studies have provided evidence suggesting that neuroinflammation plays an important role in the pathogenesis of PD. In this study, we used lipopolysaccharide (LPS)-induced in vitro and in vivo inflammation models to investigate whether human mesenchymal stem cells (hMSCs) have a protective effect on the dopaminergic system through anti-inflammatory mechanisms. The hMSC treatment significantly decreased LPS-induced microglial activation, tumor necrosis factor (TNF)-alpha, inducible nitric oxide synthase (iNOS) mRNA expression, and production of NO and TNF-alpha compared with the LPS-only treatment group. In co-cultures of microglia and mesencephalic dopaminergic neurons, hMSC treatment significantly decreased the loss of tyrosine hydroxylase-immunopositive (TH-ip) cells. The hMSC treatment in rats showed that TH-ip neuronal loss induced by LPS stimulation in the SN was considerably decreased and was clearly accompanied by a decrease in activation of microglia, as well as TNF-alpha and iNOS mRNA expression and production of TNF-alpha. These data suggest that hMSCs have a neuroprotective effect on dopaminergic neurons through anti-inflammatory actions mediated by the modulation of microglial activation. Along with various trophic effects and trans-differentiational potency, the anti-inflammatory properties of MSCs could have major therapeutic implications in the treatment of PD.

OBJECTIVE: Neuroprotective or regenerative strategies are invaluable in multiple system atrophy (MSA) due to its rapid progression with fatal prognosis. We evaluated the efficacy of autologous mesenchymal stem cells (MSC) in patients with MSA-cerebellar type (MSA-C). METHODS: Thirty-three patients with probable MSA-C and baseline unified MSA rating scale (UMSARS) scores ranging from 30 to 50 were randomly assigned to receive MSC (4 × 10(7) /injection) via intra-arterial and intravenous routes or placebo. The primary outcome was change in the total UMSARS scores from baseline throughout a 360-day follow-up period between groups. Secondary outcomes were changes in the UMSARS part II scores, cerebral glucose metabolism, gray matter density, and cognitive performance over a 360-day period. RESULTS: The mixed model analysis of neurological deficits revealed a significant interaction effect between treatment group and time, suggesting that the MSC group had a smaller increase in total and part II UMSARS scores compared with the placebo group (p = 0.047 and p = 0.008, respectively). Cerebral glucose metabolism and gray matter density at 360 days relative to the baseline were more extensively decreased in the cerebellum and the cerebral cortical areas, along with greater deterioration of frontal cognition in the placebo group compared with the MSC group. We found no serious adverse effects that were directly related to MSC treatment. However, intra-arterial infusion resulted in small ischemic lesions on magnetic resonance imaging. INTERPRETATION: MSC therapy could delay the progression of neurological deficits in patients with MSA-C, suggesting the potential of MSC therapy as a treatment candidate of MSA.