iPSC-derived mesenchymal stromal cells are less supportive than primary MSCs for co-culture of hematopoietic progenitor cells

Abstract In vitro culture of hematopoietic stem and progenitor cells (HPCs) is supported by a suitable cellular microenvironment, such as mesenchymal stromal cells (MSCs)—but MSCs are heterogeneous and poorly defined. In this study, we analyzed whether MSCs derived from induced pluripotent stem cells (iPS-MSCs) provide a suitable cellular feeder layer too. iPS-MSCs clearly supported proliferation of HPCs, maintenance of a primitive immunophenotype (CD34+, CD133+, CD38-), and colony-forming unit (CFU) potential of CD34+ HPCs. However, particularly long-term culture-initiating cell (LTC-IC) frequency was lower with iPS-MSCs as compared to primary MSCs. Relevant genes for cell-cell interaction were overall expressed at similar level in MSCs and iPS-MSCs, whereas VCAM1 was less expressed in the latter. In conclusion, our iPS-MSCs support in vitro culture of HPCs; however, under the current differentiation and culture conditions, they are less suitable than primary MSCs from bone marrow

Coronary microvascular dysfunction as assessed by angiography-derived index of microvascular resistance co-localizes with and may explain the presence of ischemia in stress-cardiac magnetic resonance imaging in the absence of coronary artery disease

IntroductionIschemia with no obstructive coronary disease (INOCA) is a frequent phenomenon in the cath lab. A possible cause is coronary microvascular dysfunction (CMD), which may be assessed by invasive testing with possible complications; therefore, less invasive approaches have emerged, such as the angiography-derived index of microvascular resistance (aIMR). The aim of our study was to investigate the association of single-vessel aIMR as a measure of CMD with areas of INOCA in stress testing. MethodsWe measured aIMR in 286 vessels from 102 patients undergoing both stress cMRI and coronary angiography. Groups were (a) INOCA group (93 vessels, 32 patients); (b) coronary artery disease (CAD) control group (116 vessels, 42 patients) with ischemia due to relevant stenosis; and (c) control group (77 vessels, 28 patients) without ischemia or relevant stenosis. ResultsINOCA patients presented higher mean aIMR (28.3 +/- 5.7) compared to both CAD patients (17.4 +/- 5.7, p < 0.001) and controls (22.1 +/- 5.9, p < 0.001). Furthermore, in INOCA patients aIMR was significantly increased (33.0 +/- 8.1 vs. 25.8 +/- 6.3, p = 0.021) in vessels with vs. without ischemia. Single vessel aIMR presented a very good diagnostic efficiency in detecting INOCA [AUC 0.865 (0.804-0.925), optimal cut-off 27.1, p < 0.001]. ConclusionCMD, as assessed by 3-vessel aIMR, co-localizes with and may explain the presence of ischemia in stress-cMRI in INOCA

Quantitative Flow Ratio Is Related to Anatomic Left Main Stem Lesion Parameters as Assessed by Intravascular Imaging

Introduction: Previously, an association between anatomic left main stem (LMS) lesion parameters, as described by intravascular ultrasound (IVUS) and fractional flow reserve (FFR), was shown. Quantitative flow ratio (QFR) is a novel, promising technique which can assess functional stenosis relevance based only on angiography. However, as little is known about the relationship between anatomic LMS parameters and QFR, it was thus investigated in this study. Methods: In 53 patients with LMS disease, we tested the association between anatomic assessment using OCT (n = 28) or IVUS (n = 25) on the one hand and functional assessment as determined by QFR on the other hand. LMS-QFR was measured using a dedicated approach, averaging QFR over left anterior descending (LAD) and circumflex (LCX) and manually limiting segment of interest to LMS. Results: The minimal luminal area of the LMS (LMS-MLA) as measured by intravascular imaging showed a consistent correlation with QFR (R = 0.61, p &lt; 0.001). QFR could predict a LMS-MLA &lt; 6 mm2 with very good diagnostic accuracy (AUC 0.919) and a LMS-MLA &lt; 4.5 mm2 with good accuracy (AUC 0.798). Similar results were obtained for other stenosis parameters. Conclusions: QFR might be a valuable tool to assess LMS disease. Further studies focusing on patient outcomes are needed to further validate the effectiveness of this approach

Additional file 2: of iPSC-derived mesenchymal stromal cells are less supportive than primary MSCs for co-culture of hematopoietic progenitor cells

DNA methylation is in line with differential expression of VCAM1, CDH2, and LAMB1. DNA methylation levels of CpG dinucleotides in the genes VCAM1, CDH2, and LAMB1 were analyzed for bone marrow-derived MSCs, iPS-MSCs, and iPSCs using the Illumina 450 k BeadChip data (GSE17448 and GSE54767) as described in detail in our previous work [1]. DNA methylation level is given as β-value ranging from 0 (no methylation) to 1 (100 % methylation). Genomic location of the respective CpG sites and statistical significance of MSCs vs. iPS-MSCs are indicated (*P < 0.05, **P < 0.01, ***P < 0.001, TSS1500 = 1500 bp upstream of transcription start site; TSS200 = 200 bp upstream of TSS; UTR = untranslated region). DNA methylation of VCAM1 was higher in iPS-MSCs than MSCs. In contrast, close to the transcription start site of LAMB1 and CDH2 several CpGs revealed significantly lower DNA methylation in iPS-MSCs than primary MSCs. These epigenetic differences may therefore be relevant for the observed differences in gene expression. (PDF 362 kb

Additional file 1: of iPSC-derived mesenchymal stromal cells are less supportive than primary MSCs for co-culture of hematopoietic progenitor cells

Functional characterization of iPS-MSCs. (A) Phase contrast images of MSCs and iPS-MSCs: iPS-MSCs revealed similar fibroblastoid morphology as MSCs. (B) iPS-MSCs displayed similar immunophenotypic characteristics as primary MSCs (MFI = mean fluorescence intensity; mean ± S.D. of three biological replicates is presented; *P < 0.05, **P < 0.01). (C) MSCs and iPS-MSCs were differentiated for three weeks towards adipogenic, osteogenic, and chondrogenic lineages and subsequently stained with BODIPY/DAPI, Alizarin Red, or Alcian Blue/PAS, respectively (in analogy to our previous work [1]). Controls were simultaneously cultured in normal growth medium (DMEM supplemented with 10 % human platelet lysate). Representative images are shown. (PDF 153 kb

Lesion Geometry as Assessed by Optical Coherence Tomography Is Related to Myocardial Ischemia as Determined by Cardiac Magnetic Resonance Imaging

Introduction: Although the relationship between the geometry of coronary stenosis and the presence of myocardial ischemia is well known, the association between stenosis geometry and severity and/or extent of ischemia is still unexplored. Thus, we investigated this relationship using optical coherence tomography (OCT) to assess stenosis parameters and cardiac magnetic resonance imaging (CMR) to determine both extent and severity of ischemia. Methods: We analyzed 55 lesions from 51 patients with stable angina. Pre-interventionally, all patients underwent OCT-analysis of stenosis morphology as well as CMR to determine both the extent and severity of myocardial ischemia. Results: Percent area stenosis (%AS) was significantly associated with ischemic burden (r = 0.416, p = 0.003). Similar results could be obtained for other stenosis parameters as well as for several other parameters assessing the extent of ischemia. Furthermore, OCT-derived stenosis parameters were associated with the product of ischemic burden and severity of ischemia (%AS: r = 0.435, p = 0.002; similar results for other parameters). A Poiseuille's-law-modelled combination of stenosis length and minimal lumen diameter yielded a good diagnostic efficiency (AUC 0.787) in predicting an ischemic burden >10%. Conclusions: Our data highlight the key role of the geometry of coronary lesions in determining myocardial ischemia

Quantitative Flow Ratio Is Associated with Extent and Severity of Ischemia in Non-Culprit Lesions of Patients with Myocardial Infarction

Quantitative flow ratio (QFR) is a novel method to assess the relevance of coronary stenoses based only on angiographic projections. We could previously show that QFR is able to predict the hemodynamic relevance of non-culprit lesions in patients with myocardial infarction. However, it is still unclear whether QFR is also associated with the extent and severity of ischemia, which can effectively be assessed with imaging modalities such as cardiac magnetic resonance (CMR). Thus, our aim was to evaluate the associations of QFR with both extent and severity of ischemia. We retrospectively determined QFR in 182 non-culprit coronary lesions from 145 patients with previous myocardial infarction, and compared it with parameters assessing extent and severity of myocardial ischemia in staged CMR. Whereas ischemic burden in lesions with QFR > 0.80 was low (1.3 +/- 5.5% in lesions with QFR >= 0.90; 1.8 +/- 7.3% in lesions with QFR 0.81-0.89), there was a significant increase in ischemic burden in lesions with QFR = 0.90 vs. QFR = 10% with good diagnostic accuracy (AUC 0.779, 95%-CI: 0.666-0.892, p < 0.001). QFR may be a feasible tool to identify not only the presence, but also extent and severity of myocardial ischemia in non-culprit lesions of patients with myocardial infarction

Serum of myeloproliferative neoplasms stimulates hematopoietic stem and progenitor cells

<div><p>Background</p><p>Myeloproliferative neoplasms (MPN)—such as polycythemia vera (PV), essential thrombocythemia (ET), and myelofibrosis (MF)—are typically diseases of the elderly caused by acquired somatic mutations. However, it is largely unknown how the malignant clone interferes with normal hematopoiesis. In this study, we analyzed if serum of MPN patients comprises soluble factors that impact on hematopoietic stem and progenitor cells (HPCs).</p><p>Methods</p><p>CD34⁺ HPCs were cultured in medium supplemented with serum samples of PV, ET, or MF patients, or healthy controls. The impact on proliferation, maintenance of immature hematopoietic surface markers, and colony forming unit (CFU) potential was systematically analyzed. In addition, we compared serum of healthy young (<25 years) and elderly donors (>50 years) to determine how normal aging impacts on the hematopoiesis-supportive function of serum.</p><p>Results</p><p>Serum from MF, PV and ET patients significantly increased proliferation as compared to controls. In addition, serum from MF and ET patients attenuated the loss of a primitive immunophenotype during <i>in vitro</i> culture. The CFU counts were significantly higher if HPCs were cultured with serum of MPN patients as compared to controls. Furthermore, serum of healthy young <i>versus</i> old donors did not evoke significant differences in proliferation or immunophenotype of HPCs, whereas the CFU frequency was significantly increased by serum from elderly patients.</p><p>Conclusion</p><p>Our results indicate that serum derived from patients with MPN comprises activating feedback signals that stimulate the HPCs–and this stimulatory signal may result in a viscous circle that further accelerates development of the disease.</p></div