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Tanzil J.T.I.,National University of Singapore | Tanzil J.T.I.,University of Amsterdam | Tanzil J.T.I.,Singapore MIT Alliance in Research and Technology | Brown B.E.,Northumbria University | And 5 more authors.
Global Change Biology | Year: 2013

This study reports the first well-replicated analysis of continuous coral growth records from warmer water reefs (mean annual sea surface temperatures (SST) >28.5 °C) around the Thai-Malay Peninsula in Southeast Asia. Based on analyses of 70 colonies sampled from 15 reefs within six locations, region-wide declines in coral calcification rate (ca. 18.6%), linear extension rate (ca. 15.4%) and skeletal bulk density (ca. 3.9%) were observed over a 31-year period from 1980 to 2010. Decreases in calcification and linear extension rates were observed at five of the six locations and ranged from ca. 17.2-21.6% and ca. 11.4-19.6%, respectively, whereas decline in skeletal bulk density was a consequence of significant reductions at only two locations (ca. 6.9% and 10.7%). A significant link between region-wide growth rates and average annual SST was found, and Porites spp. demonstrated a high thermal threshold of ca. 29.4 °C before calcification rates declined. Responses at individual locations within the region were more variable with links between SST and calcification rates being significant at only four locations. Rates of sea temperature warming at locations in the Andaman Sea (Indian Ocean) (ca. 1.3 °C per decade) were almost twice those in the South China Sea (Pacific Ocean) (ca. 0.7 °C per decade), but this was not reflected in the magnitude of calcification declines at corresponding locations. Considering that massive Porites spp. are major reef builders around Southeast Asia, this region-wide growth decline is a cause for concern for future reef accretion rates and resilience. However, this study suggests that the future rates and patterns of change within the region are unlikely to be uniform or dependent solely on the rates of change in the thermal environment. © 2013 John Wiley & Sons Ltd.

Poon Z.,Singapore MIT Alliance in Research and Technology | Lee W.C.,Singapore MIT Alliance in Research and Technology | Lee W.C.,National University of Singapore | Guan G.,Singapore MIT Alliance in Research and Technology | And 9 more authors.
Stem Cells Translational Medicine | Year: 2014

Human tissue repair deficiencies can be supplemented through strategies to isolate, expand in vitro, and reimplant regenerative cells that supplant damaged cells or stimulate endogenous repair mechanisms. Bone marrow-derived mesenchymal stromal cells (MSCs), a subset of which is described as mesenchymal stem cells, are leading candidates for cell-mediated bone repair and wound healing, with hundreds of ongoing clinical trials worldwide. An outstanding key challenge for successful clinical translation of MSCs is the capacity to produce large quantities of cells in vitro with uniform and relevant therapeutic properties. By leveraging biophysical traits of MSC subpopulations and label-free microfluidic cell sorting, we hypothesized and experimentally verified that MSCs of large diameter within expanded MSC cultures were osteoprogenitors that exhibited significantly greater efficacy over other MSC subpopulations in bone marrow repair. Systemic administration of osteoprogenitor MSCs significantly improved survival rates (>80%) as compared with other MSC subpopulations (0%) for preclinical murine bone marrow injury models. Osteoprogenitor MSCs also exerted potent therapeutic effects as “cell factories” that secreted high levels of regenerative factors such as interleukin-6 (IL-6), interleukin-8 (IL-8), vascular endothelial growth factor A, bone morphogenetic protein 2, epidermal growth factor, fibroblast growth factor 1, and angiopoietin-1; this resulted in increased cell proliferation, vessel formation, and reduced apoptosis in bone marrow. This MSC subpopulation mediated rescue of damaged marrow tissue via restoration of the hematopoiesis-supporting stroma, as well as subsequent hematopoiesis. Together, the capabilities described herein for label-freeisolation of regenerative osteoprogenitor MSCs can markedly improve the efficacy of MSC-based therapies. © AlphaMed Press.

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