人類脂肪細胞
美國科學家研究發現，“嬰兒”脂肪細胞（即未成熟脂肪細胞）潛伏在血管壁中，等待着過剩的卡路里幫助它們長成成年“魔鬼”，增加人們的體重。這是首次發現這類細胞的“巢穴”，該結果有助於指導將來發現阻止這些細胞製造多餘脂肪的方法，並有望在其它醫療實踐上得到應用。相關論文2008年9月18日在線發表於《科學》（Science）雜誌上。
通常情況下，祖細胞會在多種情況下製造新的脂肪細胞，比如當年幼身體生長並需要形成脂肪細胞的時候。它們對於維持體重的穩定也很必要，老的脂肪細胞死去，必須由新的進行補充，然而，當熱量攝取過剩時，不僅現有脂肪細胞會變大以儲存更多脂肪，祖細胞也會製造新的脂肪細胞。
美國德州大學西南醫學中心的Jonathan Graff和同事利用遺傳手段令小鼠幹細胞發熒光，據此發現這些未成熟脂肪細胞位於穿過脂肪組織的血管壁中。Graff說：“它們並不是附着在血管壁上，而是成爲了血管壁的一部分。”他認爲，這種“安排”自有用意，它能夠使未成熟脂肪細胞對餐後出現在血液中的葡萄糖等營養元素作出響應。當感受到過剩熱量攝取時，它們就會從血管壁中凸現出來，成長爲成熟脂肪細胞。這種安排確保了它們位於其它脂肪細胞間的適當位置。
Graff表示：“此次發現具有理論和實踐的雙重意義。鑑別出脂肪細胞祖細胞並發現它們的位置，爲我們提供了令人興奮的治療機會。我們也許能夠開發出新的治療手段，來幫助肥胖、糖尿病以及其它代謝問題的患者。”
原始出處：
Science，DOI: 10.1126/science.1156232，Wei Tang，Jonathan M. Graff
White Fat Progenitor Cells Reside in the Adipose Vasculature
Wei Tang 1, Daniel Zeve 1, Jaemyoung Suh 1, Darko Bosnakovski 1, Michael Kyba 1, Bob Hammer 2, Michelle D. Tallquist 2, Jonathan M. Graff 3*
1 Department of Developmental Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, NB5.118, Dallas, TX 75390C9133, USA.
2 Department of Molecular Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, NB5.118, Dallas, TX 75390C9133, USA.
3 Department of Developmental Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, NB5.118, Dallas, TX 75390C9133, USA.; Department of Molecular Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, NB5.118, Dallas, TX 75390C9133, USA.; Department of Internal Medicine, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, NB5.118, Dallas, TX 75390C9133, USA.
White adipose (fat) tissues regulate metabolism, reproduction and lifespan. Adipocytes form throughout life, with the most marked expansion of the lineage occurring during the postnatal period. Adipocytes develop in coordination with the vasculature, but the identity and location of white adipocyte progenitor cells in vivo are unknown. We used genetically marked mice to isolate proliferating and renewing adipogenic progenitors. We find that most adipocytes descend from a pool of these proliferating progenitors that are already committed either prenatally or early in postnatal life. These progenitors reside in the mural cell compartment of the adipose vasculature but not in the vasculature of other tissues. Thus, the adipose vasculature appears to function as a progenitor niche and may provide signals for adipocyte development.