PROBLEM TO BE SOLVED: To provide methods of proliferating mesenchymal stem cells, and generated cell populations of mesenchymal stem cells.SOLUTION: Methods of proliferating undifferentiated mesenchymal stem cells (MSCs) comprise culturing a population of MSCs including the undifferentiated MSCs in a medium comprising nicotinamide and fibroblast growth factor 4 (FGF4), thereby generating a proliferated population of the undifferentiated MSCs. The medium is devoid of added additional basic fibroblast growth factor (bFGF), platelet derived growth factor (PDGF) and epidermal growth factor (EGF).SELECTED DRAWING: None【課題】間葉系幹細胞を増殖させる方法、及び前記間葉系幹細胞の生成された細胞集団。【解決手段】ニコチンアミドと線維芽細胞成長因子４（ＦＧＦ４）とを含む培地中で、未分化の前記間葉系幹細胞（ＭＳＣ）を含む前記ＭＳＣの集団を培養することによって、増殖された未分化の前記ＭＳＣの集団を生成する工程を含み、前記培地は追加で添加された塩基性線維芽細胞成長因子（ｂＦＧＦ）、血小板由来成長因子（ＰＤＧＦ）、および内皮成長因子（ＥＧＦ）を含まない、未分化の前記ＭＳＣを増殖させる方法。【選択図】なし
