The stromal vascular fraction (SVF) in adipose tissue contains a pool of various stem and progenitor cells, but the existence of hematopoietic stem and progenitor cells (HSPCs) in the SVF has not been seriously considered. We detected the presence of HSPCs in the SVF by phenotypically probing with Lin ؊ Sca-1 ؉ c-kit ؉ (LSK) and functionally confirming the presence using colony-forming cell assay and assessing the long-term multilineage reconstitution ability after SVF transplantation. The LSK population in the SVF was 0.004% plus or minus 0.001%, and 5 ؋ 10 5 freshly isolated SVF cells gave rise to 13 plus or minus 4 multilineage colonies. In addition, 0.15% plus or minus 0.03% of SVF cells was home to bone marrow (BM), especially near vascular and endosteal regions, 24 hours after blood transplantation. SVF transplantation was capable of generating a longterm (> 16 weeks), but variable extent (2.1%-32.1%) multilineage reconstitution in primary recipients, which was subsequently transferred to the secondary recipients by BM transplantation. All HSPCs within the SVF originated from the BM. Furthermore, the granulocyte-colonystimulating factor (G-CSF) mobilization of HSPCs from BM markedly elevated the number of phenotypic and functional HSPCs in the SVF, which induced a high efficiency long-term reconstitution in multilineage hematopoiesis in vivo. Our results provide compelling evidence that adipose tissue is a novel extramedullary tissue possessing phenotypic and functional HSPCs. (Blood. 2010;115:957-964) IntroductionHematopoietic stem and progenitor cells (HSPCs) in the complicated hierarchy of the hematopoietic system maintain themselves and generate many kinds of blood cells throughout life. To maintain their proper functioning, HSPCs reside in a special microenvironment called a niche. [1][2][3] Bone marrow (BM) is a dominant organ possessing a niche for HSPCs during adulthood. It is well known that a small fraction of HSPCs constantly circulate between the BM and peripheral blood without any stimulation. 4,5 The exiting and re-entering of HSPCs is mediated by interactions between several surface molecules, such as selectins and integrins. 1 In principle, on the way from peripheral blood back to the BM, HSPCs can settle down if the proper environment is provided. Supporting this concept, several extramedullary tissues were identified as HSPC-containing organs, including the liver, 6 spleen, 7 muscle, 8,9 and thoracic duct. 10 Among these organs, the liver and spleen are well-known locations for extramedullary hematopoiesis. 1 In both tissues, HSPCs reside close to sinusoidal endothelial cells, which may provide a preferential microenvironment. 6,11 The mechanism underlying HSPC maintenance in these extramedullary organs remains unclear, though the HSPCs still conserve their function properly. [6][7][8][9][10] Adipose tissues contain many different types of adult stem cells that can be used for therapeutic purposes, especially for tissue regeneration. 12 Adipose tissue is composed of lipid-filled mature ad...

Background Changes in gene-specific promoter methylation may result from aging and environmental influences. Atherosclerosis is associated with aging and environmental effects. Thus, promoter methylation profiling may be used as an epigenetic tool to evaluate the impact of aging and the environment on atherosclerosis development. However, gene-specific methylation changes are currently inadequate epigenetic markers for predicting atherosclerosis and cardiovascular disease pathogenesis. Results We profiled and validated changes in gene-specific promoter methylation associated with atherosclerosis using stenosis radiophenotypes of cranial vessels and blood inflammatory cells rather than direct sampling of atherosclerotic plaques. First, we profiled gene-specific promoter methylation changes using digital restriction enzyme analysis of methylation (DREAM) sequencing in peripheral blood mononuclear cells from eight samples each of cranial vessels with and without severe-stenosis radiophenotypes. Using DREAM sequencing profiling, 11 tags were detected in the promoter regions of the ACVR1C, ADCK5, EFNA2, ENOSF1, GLS2, KNDC1, MTNR1B, PACSIN3, PAX8-AS1, TLDC1, and ZNF7 genes. Using methylation evaluation, we found that EFNA2, ENOSF1, GLS2, KNDC1, MTNR1B, PAX8-AS1, and TLDC1 showed > 5% promoter methylation in non-plaque intima, atherosclerotic vascular tissues, and buffy coats. Using logistic regression analysis, we identified hypomethylation of MTNR1B as an independent variable for the stenosis radiophenotype prediction model by combining it with traditional atherosclerosis risk factors including age, hypertension history, and increases in creatinine, lipoprotein (a), and homocysteine. We performed fivefold cross-validation of the prediction model using 384 patients with ischemic stroke (50 [13%] no-stenosis and 334 [87%] > 1 stenosis radiophenotype). For the cross-validation, the training dataset included 70% of the dataset. The prediction model showed an accuracy of 0.887, specificity to predict stenosis radiophenotype of 0.940, sensitivity to predict no-stenosis radiophenotype of 0.533, and area under receiver operating characteristic curve of 0.877 to predict stenosis radiophenotype from the test dataset including 30% of the dataset. Conclusions We identified and validated MTNR1B hypomethylation as an epigenetic marker to predict cranial vessel atherosclerosis using stenosis radiophenotypes and blood inflammatory cells rather than direct atherosclerotic plaque sampling.

No abstract

No abstract

No abstract