Aird Allison L, Nevitt Christopher D, Christian Katelyn, Williams Stuart K, Hoying James B, LeBlanc Amanda J
Cardiovascular Innovation Institute, Jewish Hospital and University of Louisville, Louisville, KY 40202, United States.
Cardiovascular Innovation Institute, Jewish Hospital and University of Louisville, Louisville, KY 40202, United States; Department of Biochemistry and Molecular Biology, Jewish Hospital and University of Louisville, Louisville, KY 40202, United States.
Exp Gerontol. 2015 Mar;63:18-26. doi: 10.1016/j.exger.2015.01.044. Epub 2015 Jan 21.
Adipose-derived regenerative and stem cells, defined collectively as the stromal vascular fraction (SVF), support the formation of neovascular networks at the site of implantation. The effect of advancing age on SVF cell population effectiveness towards stimulated neovascularization was evaluated.
SVF was enzymatically isolated from adipose of young (ySVF, 4 months) or old (oSVF, 24 months) Fisher-344 rats, combined with type I collagen and polymerized. Encapsulated SVF was implanted subcutaneously into young Rag1 mice for two or four weeks. Angiogenic function of age-dependent SVF was also extensively evaluated in vitro using standard assays.
In vitro studies indicated no difference in angiogenic function between ySVF and oSVF (viability, proliferation, migration, and tube-formation). At two weeks post-implantation, there was no age-related difference in percent apoptosis in explanted constructs. By four weeks post-implantation, oSVF implants displayed 36% less total vessels/mm(2), 43% less perfused vessels/mm(2), and exhibited greater percent apoptosis compared to ySVF (n ≥ 12). Blocking thrombospondin-1 (Thbs-1), a protein found to be highly expressed in oSVF but not ySVF, increased the percent of perfused vascular volume and vessel diameters in oSVF constructs after two weeks compared to oSVF implants treated with control antibody.
Advancing donor age reduces the potential of adipose-derived SVF to derive a mature microcirculation, but does not hinder initial angiogenesis. However, modulation of Thbs-1 may improve this outcome. This data suggests that greater pruning, dysfunctional structural adaptation and/or poor maturation with initiation of blood flow may occur in oSVF.
脂肪来源的再生细胞和干细胞统称为基质血管成分（SVF），可支持植入部位新血管网络的形成。评估了年龄增长对SVF细胞群体促进新血管形成有效性的影响。
从年轻（ySVF，4个月）或年老（oSVF，24个月）的Fisher-344大鼠脂肪中酶解分离出SVF，与I型胶原蛋白混合并聚合。将包封的SVF皮下植入年轻的Rag1小鼠体内2周或4周。还使用标准试验在体外广泛评估了年龄依赖性SVF的血管生成功能。
体外研究表明，ySVF和oSVF在血管生成功能（活力、增殖、迁移和管形成）方面没有差异。植入后2周，外植构建体中的凋亡百分比没有年龄相关差异。植入后4周，与ySVF相比，oSVF植入物的总血管/mm²减少36%，灌注血管/mm²减少43%，且凋亡百分比更高（n≥12）。阻断血小板反应蛋白-1（Thbs-1）（一种在oSVF中高表达但在ySVF中不表达的蛋白质），与用对照抗体处理的oSVF植入物相比，2周后oSVF构建体中灌注血管体积百分比和血管直径增加。
供体年龄增长会降低脂肪来源的SVF形成成熟微循环的潜力，但不妨碍初始血管生成。然而，调节Thbs-1可能会改善这一结果。该数据表明，oSVF可能会出现更多的修剪、功能失调的结构适应和/或血流开始时成熟不良的情况。
