摘要：The knee is a.multi-component orga. system comprised of severa. tissues which function coordina.ely to provide mobility. Injury to a.y one component compromises the integrity of the system a.d lea.s to a.a.ta.ion of the other components. Over time, such events often lea. to dysfunction a.d degenera.ion of the knee. Therefore, there ha. been considera.le resea.ch empha.is to repa.r injured components in the knee including ca.tila.e, menisci, a.d liga.ents. a.proa.hes to improving hea.ing a.d repa.r/regenera.ion of knee tissues ha.e included surgery, a.ti-sense gene thera.y, injection of growth fa.tors a.d infla.ma.ory cytokine a.ta.onists, tra.spla.ta.ion of in vitro expa.ded chondrocytes, enha.cement of endogenous cells via.microfra.ture, injection of mesenchyma. stem cells, a.d impla.ta.ion of in vitro tissue engineered constructs. Some of these a.proa.hes ha.e lea. to tempora.y improvement in knee functioning, while others offer the potentia. to restore function a.d tissue integrity for longer periods of time. This a.ticle will review the sta.us of ma.y of these a.proa.hes, a.d provide a.perspective on their limita.ions a.d potentia. to contribute to restora.ion of knee function a.ross the lifespa..

摘要：Mesenchyma. stem/progenitor cells (MSC/MPC) from a.va.iety of tissue sources (bone ma.row, a.ipose tissue, fa. pa.s, synovia. membra.es, synovia. fluid, skin, muscle a.d periostea. tissue) ha.e been widely a.plied for tissue engineering a.plica.ions to genera.e repla.ements for injured or degenera.ed tissues. a.terna.ively, they ha.e a.so been injected a. free cells in a. a.tempt to fa.ilita.e in vivo repa.r. Nea.ly a.l studies reported ha.e used mixed cell popula.ions of MSC/MPC, usua.ly defined by cell surfa.e phenotypes a.d/or functiona. a.ility to differentia.e towa.ds multiple cell linea.es. Using more deta.led cell surfa.e phenotyping a.d limiting dilution a.proa.hes to isola.e individua. MSC/MPC clones ha.e indica.ed tha. such mixed cell popula.ions a.e very heterogeneous. In a.dition subsets of cells from different sources ma. ha.e epigenetic modifica.ions. While it is clea. tha. MSC/MPC cells exhibit heterogeneity, the question of why this is the ca.e ha. not been well a.dressed. This review will a.dress some of these issues, a. well a. provide some insights into the implica.ions when using such diverse cells for tissue engineering a.plica.ions.