Early Detection of Cardiotoxicity Using [64Cu]Cu-NODAGA-E[(cRGDyK)]2 PET Imaging in a Rat Model of Doxorubicin-Induced Heart Failure.

Doxorubicin (DOX) is a common and highly effective chemotherapeutic. However, its use is limited by cardiotoxic effects and the lack of methods to detect these at early time points. In the present study, we evaluated if [64Cu]Cu-NODAGA-E[(cRGDyK)]2 positron emission tomography-computed tomography ([64Cu]Cu-RGD PET/CT) could detect cardiotoxicity in a rat model of DOX-induced heart failure. Male Lewis rats were divided into two groups and treated with either a cumulative dose of 15 mg/kg of DOX or left untreated. Cardiac anatomy and function were assessed using magnetic resonance imaging at baseline and in week 8. [64Cu]Cu-RGD PET/CT scans were performed in week 4. DOX treatment led to a decline in pump function as well as an increase in cardiac and thymic uptake of [64Cu]Cu-RGD. In addition, DOX altered cardiac gene expression, led to infiltration of immune cells, reduced endothelial content, and increased interstitial fibrosis. Furthermore, concentrations of inflammatory plasma proteins were increased in the DOX group. In conclusion, DOX treatment resulted in the development of cardiotoxicity and heart failure, which could be detected using [64Cu]Cu-RGD PET/CT at early time points. [64Cu]Cu-RGD uptake in the myocardial septum and thymus predicted a low left ventricular ejection fraction in week 8.

[68Ga]Ga-NODAGA-E[(cRGDyK)]2 angiogenesis PET following myocardial infarction in an experimental rat model predicts cardiac functional parameters and development of heart failure.

BACKGROUND: Angiogenesis has increasingly been a target for imaging and treatment over the last decade. The integrin αvß3 is highly expressed in cells during angiogenesis and are therefore a promising target for imaging. In this study, we aimed to investigate the PET tracer [68Ga]Ga-RGD as a marker of angiogenesis following MI and its ability to predict cardiac functional parameters. METHODS: First, the real-time interaction between [68Ga]Ga-RGD and integrin αvß3 was investigated using surface plasmon resonance (SPR). Second, an animal study was performed to investigate the [68Ga]Ga-RGD uptake in the infarcted area after one and four weeks following MI in a rat model (MI = 68, sham surgery = 36). Finally, the specificity of the [68Ga]Ga-RGD tracer was evaluated ex vivo using histology, autoradiography, gamma counting and flow cytometry. RESULTS: SPR showed that [68Ga]Ga-RGD has a high affinity for integrin αvß3, forming a strong and stable binding. PET/CT showed a significantly higher uptake of [68Ga]Ga-RGD in the infarcted area compared to sham one week (p < 0.001) and four weeks (p < 0.001) after MI. The uptake of [68Ga]Ga-RGD after one week correlated to end diastolic volume (r = 0.74, p < 0.001) and ejection fraction (r = - 0.71, p < 0.001) after four weeks. CONCLUSION: This study demonstrates that [68Ga]Ga-RGD has a high affinity for integrin αvß3, which enables the evaluation of angiogenesis and remodeling. The [68Ga]Ga-RGD uptake after one week indicates that [68Ga]Ga-RGD may be used as an early predictor of cardiac functional parameters and possible development of heart failure after MI. These encouraging data supports the clinical translation and future use in MI patients.

The Initial Cardiac Tissue Response to Cryopreserved Allogeneic Adipose Tissue-Derived Mesenchymal Stromal Cells in Rats with Chronic Ischemic Cardiomyopathy.

Mesenchymal stromal cells have proven capable of improving cardiac pump function in patients with chronic heart failure, yet little is known about their mode of action. The aim of the study was to investigate the short-term effect of cryopreserved allogeneic rat adipose tissue-derived stromal cells (ASC) on cardiac composition, cellular subpopulations, and gene transcription in a rat model of chronic ischemic cardiomyopathy (ICM). Myocardial infarction (MI) was induced by permanent ligation of the left anterior descending coronary artery. After 6 weeks, the rats were treated with ASCs, saline, or no injection, using echo-guided trans-thoracic intramyocardial injections. The cardiac tissue was subsequently collected for analysis of cellular subpopulations and gene transcription 3 and 7 days after treatment. At day 3, an upregulation of genes associated with angiogenesis were present in the ASC group. On day 7, increases in CCR2+ and CD38+ macrophages (p = 0.047 and p = 0.021), as well as in the CD4/CD8 lymphocyte ratio (p = 0.021), were found in the ASC group compared to the saline group. This was supported by an upregulation of genes associated with monocytes/macrophages. In conclusion, ASC treatment initiated an immune response involving monocytes/macrophages and T-cells and induced a gene expression pattern associated with angiogenesis and monocyte/macrophage differentiation.

Rubidium-82 PET imaging is feasible in a rat myocardial infarction model.

BACKGROUND: Small-animal myocardial infarct models are frequently used in the assessment of new cardioprotective strategies. A validated quantification of perfusion using a non-cyclotron-dependent PET tracer would be of importance in monitoring response to therapy. We tested whether myocardial PET perfusion imaging is feasible with Rubidium-82 (82Rb) in a small-animal scanner using a rat myocardial infarct model. METHODS: 18 Sprague-Dawley rats underwent permanent coronary artery ligation (infarct group), and 11 rats underwent ischemia-reperfusion (reperfusion group) procedure. 82Rb-PET and magnetic resonance imaging (MRI) were conducted before and after the intervention. Perfusion was compared to both left ventricle ejection fraction (LVEF) and infarct size assessed by MRI. RESULTS: Follow-up global 82Rb-uptake correlated significantly with infarct size (infarct group: r = -0.81, P < 0.001 and reperfusion group: r = -0.61, P = 0.04). Only 82Rb-uptake in the infarct group correlated with LVEF. At follow-up, a higher segmental 82Rb-uptake in the infarct group was associated with better wall motion (ß = 0.034, CI [0.028;0.039], P < 0.001, R2 = 0.30), and inversely associated with scar transmurality (ß = -2.4 [-2.6; -2.2], P < 0.001, R2 = 0.59). The associations were similar for the reperfusion group. CONCLUSION: 82Rb-PET is feasible in small animal scanners despite the long positron range and enables fast and time-efficient myocardial perfusion imaging in rat models.

Development of large-scale manufacturing of adipose-derived stromal cells for clinical applications using bioreactors and human platelet lysate.

In vitro expanded adipose-derived stromal cells (ASCs) are a useful resource for tissue regeneration. Translation of small-scale autologous cell production into a large-scale, allogeneic production process for clinical applications necessitates well-chosen raw materials and cell culture platform. We compare the use of clinical-grade human platelet lysate (hPL) and fetal bovine serum (FBS) as growth supplements for ASC expansion in the automated, closed hollow fibre quantum cell expansion system (bioreactor). Stromal vascular fractions were isolated from human subcutaneous abdominal fat. In average, 95 × 106 cells were suspended in 10% FBS or 5% hPL medium, and loaded into a bioreactor coated with cryoprecipitate. ASCs (P0) were harvested, and 30 × 106 ASCs were reloaded for continued expansion (P1). Feeding rate and time of harvest was guided by metabolic monitoring. Viability, sterility, purity, differentiation capacity, and genomic stability of ASCs P1 were determined. Cultivation of SVF in hPL medium for in average nine days, yielded 546 × 106 ASCs compared to 111 × 106 ASCs, after 17 days in FBS medium. ASCs P1 yields were in average 605 × 106 ASCs (PD [population doublings]: 4.65) after six days in hPL medium, compared to 119 × 106 ASCs (PD: 2.45) in FBS medium, after 21 days. ASCs fulfilled ISCT criteria and demonstrated genomic stability and sterility. The use of hPL as a growth supplement for ASCs expansion in the quantum cell expansion system provides an efficient expansion process compared to the use of FBS, while maintaining cell quality appropriate for clinical use. The described process is an obvious choice for manufacturing of large-scale allogeneic ASC products.

Senescence and quiescence in adipose-derived stromal cells: Effects of human platelet lysate, fetal bovine serum and hypoxia.

BACKGROUND AIMS: Adipose-derived stromal cells (ASCs) are attractive sources for cell-based therapies. The hypoxic niche of ASCs in vivo implies that cells will benefit from hypoxia during in vitro expansion. Human platelet lysate (hPL) enhances ASC proliferation rates, compared with fetal bovine serum (FBS) at normoxia. However, the low proliferation rates of FBS-expanded ASCs could be signs of senescence or quiescence. We aimed to determine the effects of hypoxia and hPL on the expansion of ASCs and whether FBS-expanded ASCs are senescent or quiescent. METHODS: ASCs expanded in FBS or hPL at normoxia or hypoxia until passage 7 (P7), or in FBS until P5 followed by culture in hPL until P7, were evaluated by proliferation rates, cell cycle analyses, gene expression and ß-galactosidase activity. RESULTS: hPL at normoxia and hypoxia enhanced proliferation rates and expression of cyclins, and decreased G0/G1 fractions and expression of p21 and p27, compared with FBS. The shift from FBS to hPL enhanced cyclin levels, decreased p21 and p27 levels and tended to decrease G0/G1 fractions. CONCLUSION: Hypoxia does not add to the effect of hPL during ASC expansion with regard to proliferation, cell cycle regulation and expression of cyclins, p21 and p27. hPL rejuvenates FBS-expanded ASCs with regard to cell cycle regulation and expression of cyclins, p21 and p27. This indicates a reversible arrest. Therefore, we conclude that ASCs expanded until P7 are not senescent regardless of culture conditions.

Culture expansion of adipose derived stromal cells. A closed automated Quantum Cell Expansion System compared with manual flask-based culture.

BACKGROUND: Adipose derived stromal cells (ASCs) are a rich and convenient source of cells for clinical regenerative therapeutic approaches. However, applications of ASCs often require cell expansion to reach the needed dose. In this study, cultivation of ASCs from stromal vascular fraction (SVF) over two passages in the automated and functionally closed Quantum Cell Expansion System (Quantum system) is compared with traditional manual cultivation. METHODS: Stromal vascular fraction was isolated from abdominal fat, suspended in α-MEM supplemented with 10% Fetal Bovine Serum and seeded into either T75 flasks or a Quantum system that had been coated with cryoprecipitate. The cultivation of ASCs from SVF was performed in 3 ways: flask to flask; flask to Quantum system; and Quantum system to Quantum system. In all cases, quality controls were conducted for sterility, mycoplasmas, and endotoxins, in addition to the assessment of cell counts, viability, immunophenotype, and differentiation potential. RESULTS: The viability of ASCs passage 0 (P0) and P1 was above 96%, regardless of cultivation in flasks or Quantum system. Expression of surface markers and differentiation potential was consistent with ISCT/IFATS standards for the ASC phenotype. Sterility, mycoplasma, and endotoxin tests were consistently negative. An average of 8.0 × 107 SVF cells loaded into a Quantum system yielded 8.96 × 107 ASCs P0, while 4.5 × 106 SVF cells seeded per T75 flask yielded an average of 2.37 × 106 ASCs-less than the number of SVF cells seeded. ASCs P1 expanded in the Quantum system demonstrated a population doubling (PD) around 2.2 regardless of whether P0 was previously cultured in flasks or Quantum, while ASCs P1 in flasks only reached a PD of 1.0. CONCLUSION: Manufacturing of ASCs in a Quantum system enhances ASC expansion rate and yield significantly relative to manual processing in T-flasks, while maintaining the purity and quality essential to safe and robust cell production. Notably, the use of the Quantum system entails significantly reduced working hours and thereby costs.

Myocardial perfusion of infarcted and normal myocardium in propofol-anesthetized minipigs using (82)Rubidium PET.

Cardiac Rubidium-82 ((82)Rb) positron-emission-tomography (PET) is a good method for quantification of myocardial blood flow in man. Quantification of myocardial blood flow in animals to evaluate new treatment strategies or to understand underlying disease is also of great interest but raises some challenges. Animals, which have been anesthetized during PET acquisition, might react differently to used stress medications, and therefore difficulties might exist while evaluating the resulting PET images using standard software packages from commercial vendors optimized for human hearts. Furthermore propofol, used for anesthesia, can influence myocardial perfusion and coronary flow reserve due to its vasorelaxant effect, and interactions might exist between propofol and used stress agents, potentially affecting the result of the examination. We present cardiac (82)Rb-PET studies performed in propofol-anesthetized minipigs with normal and infarcted myocardium stressed with both adenosine and dipyridamole. Despite the mentioned challenges, we were able to trace the small minipig heart with software designed for human cardiac PET and to achieve blood flow measurements comparable with results in humans with both adenosine and dipyridamole. We found dipyridamole to be a superior stress agent for this experimental setup. Finally, we were able to clearly identify the myocardial perfusion defect after an induced myocardial infarction.

Comparison of clinical grade human platelet lysates for cultivation of mesenchymal stromal cells from bone marrow and adipose tissue.

BACKGROUND: The utility of mesenchymal stromal cells (MSCs) in therapeutic applications for regenerative medicine has gained much attention. Clinical translation of MSC-based approaches requires in vitro culture-expansion to achieve a sufficient number of cells. The ideal cell culture medium should be devoid of any animal derived components. We have evaluated whether human Platelet Lysate (hPL) could be an attractive alternative to animal supplements. METHODS: MSCs from bone marrow (BMSCs) and adipose tissue-derived stromal cells (ASCs) obtained from three donors were culture expanded in three different commercially available hPL fulfilling good manufacturing practice criteria for clinical use. BMSCs and ASCs cultured in Minimum Essential Medium Eagle-alpha supplemented with 5% PLT-Max (Mill Creek), Stemulate™ PL-S and Stemulate™ PL-SP (COOK General Biotechnology) were compared to standard culture conditions with 10% fetal bovine serum (FBS). Cell morphology, proliferation, phenotype, genomic stability, and differentiation potential were analyzed. RESULTS: Regardless of manufacturer, BMSCs and ASCs cultured in hPL media showed a significant increase in proliferation capacity compared to FBS medium. In general, the immunophenotype of both BMSCs and ASCs fulfilled International Society for Cellular Therapy (ISCT) criteria after hPL media expansion. Comparative genomic hybridization measurements demonstrated no unbalanced chromosomal rearrangements for BMSCs or ASCs cultured in hPL media or FBS medium. The BMSCs and ASCs could differentiate into osteogenic, adipogenic, or chondrogenic lineages in all four culture conditions. CONCLUSION: All three clinically approved commercial human platelet lysates accelerated proliferation of BMSCs and ASCs and the cells meet the ISCT mesenchymal phenotypic requirements without exhibiting chromosomal aberrations.

Human adipose-derived stromal cells in a clinically applicable injectable alginate hydrogel: Phenotypic and immunomodulatory evaluation.

BACKGROUND AIMS: Clinical trials have documented beneficial effects of mesenchymal stromal cells from bone marrow and adipose tissue (ASCs) as treatment in patients with ischemic heart disease. However, retention of transplanted cells is poor. One potential way to increase cell retention is to inject the cells in an in situ cross-linked alginate hydrogel. METHODS: ASCs from abdominal human tissue were embedded in alginate hydrogel and alginate hydrogel modified with Arg-Gly-Asp motifs (RGD-alginate) and cultured for 1 week. Cell viability, phenotype, immunogenicity and paracrine activity were determined by confocal microscopy, dendritic cell co-culture, flow cytometry, reverse transcriptase quantitative polymerase chain reaction, Luminex multiplex, and lymphocyte proliferation experiments. RESULTS: ASCs performed equally well in alginate and RGD-alginate. After 1 week of alginate culture, cell viability was >93%. Mesenchymal markers CD90 and CD29 were reduced compared with International Society for Cellular Therapy criteria. Cells sedimented from the alginates during cultivation regained the typical level of these markers, and trilineage differentiation was performed by standard protocols. Hepatocyte growth factor mRNA was increased in ASCs cultivated in alginates compared with monolayer controls. Alginates and alginates containing ASCs did not induce dendritic cell maturation. ASCs in alginate responded like controls to interferon-gamma stimulation (licensing), and alginate culture increased the ability of ASCs to inhibit lymphocyte proliferation. DISCUSSION: ASCs remain viable in alginates; they transiently change phenotype in alginate hydrogel but regain the phenotype of monolayer controls upon release. Cells maintain their paracrine potential while in alginates; the combination of ASCs and alginate is non-immunogenic and, in fact, immunosuppressive.

Identification of a common reference gene pair for qPCR in human mesenchymal stromal cells from different tissue sources treated with VEGF.

BACKGROUND: Human mesenchymal stromal cells from the bone marrow (BMSCs) are widely used as experimental regenerative treatment of ischemic heart disease, and the first clinical trials using adipose-derived stromal cells (ASCs) are currently being conducted. Regenerative mechanisms of BMSCs and ASCs are manifold and in vitro pretreatment of the cells with growth factors has been applied to potentially enhance these properties. When characterizing the transcriptional activity of these cellular mechanisms in vitro it is important to consider the effect of the growth factor treatment on reference genes (RGs) for the normalization of qPCR data. RESULTS: BMSCs and ASCs were stimulated with vascular endothelial growth factor A-165 (VEGF) for one week, and compared with un-stimulated cells from the same donor. The stability of nine RGs through VEGF treatment as well as the donor variation was assessed using the GenEx software with the subprograms geNorm and Normfinder.The procedure of stepwise elimination was validated by poor performance of eliminated RGs in a normalization experiment using vWF as target gene. Normfinder found the TATA box binding protein (TBP) to be the most stable single RG for both BMSCs and ASCs. The optimal number of RGs for ASCs was two, and the lowest variance for vWF normalization was found using TBP and YWHAZ. For BMSCs, the optimal number of RGs was four, while the two-RG combination producing the most similar results was TBP and YWHAZ. CONCLUSIONS: A common reference gene, TBP, was found to be the most stable standalone gene, while TBP and YWHAZ were found to be the best two-RG combination for qPCR analyses for both BMSCs and ASCs through the VEGF stimulation. The presented stepwise elimination procedure was validated, while we found the final normalization experiment to be essential.

Investigating the paracrine and juxtacrine abilities of adipose-derived stromal cells in angiogenesis triple cell co-cultures.

The pro-angiogenic abilities of adipose-derived stromal cells (ASCs) make them attractive candidates for cellular therapy, especially for ischemic disease indications. However, details regarding the underlying mechanisms remain elusive. Therefore, this study aimed to investigate paracrine and juxtacrine abilities of ASCs in angiogenesis triple cell co-cultures by detailed image analysis of the vascular-like structures. Fibroblast-endothelial cell co-cultures were established, and ASCs were added directly or indirectly through inserts. The cultures were treated with antibodies or subjected to analyses using ELISA and RT2 PCR Arrays. The model consistently generated vascular-like structures. ASCs increased the total branch lengths equally well in paracrine and juxtacrine conditions, by increasing the number of branches and average branch lengths (ABL). In contrast, addition of VEGF to the model increased the number of branches, but not the ABL. Still, ASCs increased the VEGF levels in supernatants of paracrine and juxtacrine co-cultures, and anti-VEGF treatment decreased the sprouting. ASCs themselves up-regulated collagen type V in response to paracrine signals from the co-cultures. The results suggest that ASCs initiate sprouting through secretion of several paracrine factors, among which VEGF is identified, but VEGF alone does not recapitulate the paracrine actions of ASCs. By employing neutralizing antibodies and dismantling common model outputs using image analysis, the triple cell co-culture is an attractive tool for discovery of the paracrine factors in ASCs' secretome which act in concert with VEGF to improve angiogenesis.

Mesenchymal Stromal/Stem Cell Therapy Improves Salivary Flow Rate in Radiation-Induced Salivary Gland Hypofunction in Preclinical in vivo Models: A Systematic Review and Meta-Analysis.

BACKGROUND: Mesenchymal stromal/stem cells (MSCs) have been suggested for salivary gland (SG) restoration following radio-induced salivary gland damage. This study aimed to determine the safety and effectiveness of MSC therapy on radio-induced SG damage and hypofunction in preclinical in vivo studies. METHODS: PubMed and EMBASE were systematically searched for preclinical in vivo interventional studies evaluating efficacy and safety of MSC treatment following radio-induced salivary gland damage published before 10th of January 2022. The primary endpoint was salivary flow rate (SFR) evaluated in a meta-analysis. The study protocol was published and registered on PROSPERO ( www.crd.ac.uk/prospero ), registration number CRD42021227336. RESULTS: A total of 16 preclinical in vivo studies were included for qualitative analysis (858 experimental animals) and 13 in the meta-analysis (404 experimental animals). MSCs originated from bone marrow (four studies), adipose tissue (10 studies) and salivary gland tissue (two studies) and were administered intravenously (three studies), intra-glandularly (11 studies) or subcutaneously (one study). No serious adverse events were reported. The overall effect on SFR was significantly increased with a standardized mean difference (SMD) of 6.99 (95% CI: 2.55-11.42). Studies reported improvements in acinar tissue, vascular areas and paracrine factors. CONCLUSION: In conclusion, this systematic review and meta-analysis showed a significant effect of MSC therapy for restoring SG functioning and regenerating SG tissue following radiotherapy in preclinical in vivo studies without serious adverse events. MSC therapy holds significant therapeutic potential in the treatment of radio-induced xerostomia, but comprehensive, randomized, clinical trials in humans are required to ascertain their efficacy in a clinical setting.

Identical effects of VEGF and serum-deprivation on phenotype and function of adipose-derived stromal cells from healthy donors and patients with ischemic heart disease.

BACKGROUND: Adipose-derived stromal cells (ASCs) stimulated with vascular endothelial growth factor (VEGF) and serum-deprived, are applied in the first in-man double-blind placebo-controlled MyStromalCell Trial, as a novel therapeutic option for treatment of ischemic heart disease (IHD). This in vitro study explored the effect of VEGF and serum deprivation on endothelial differentiation capacity of ASCs from healthy donors and IHD patients. METHODS: ASCs stimulated with rhVEGF(A165) in serum-deprived medium for one to three weeks were compared with ASCs in serum-deprived (2% fetal bovine serum) or complete medium (10% fetal bovine serum). Expression of VEGF receptors, endothelial and stem cell markers was measured using qPCR, flow cytometry and immunocytochemistry. In vitro tube formation and proliferation was also measured. RESULTS: ASCs from VEGF-stimulated and serum-deprived medium significantly increased transcription of transcription factor FOXF1, endothelial marker vWF and receptor VEGFR1 compared with ASCs from complete medium. ASCs maintained stem cell characteristics in all conditions. Tube formation of ASCs occurred in VEGF-stimulated and serum-deprived medium. The only difference between healthy and patient ASCs was a variation in proliferation rate. CONCLUSIONS: ASCs from IHD patients and healthy donors proved equally inclined to differentiate in endothelial direction by serum-deprivation, however with no visible additive effect of VEGF stimulation. The treatment did not result in complete endothelial differentiation, but priming towards endothelial lineage.

[68Ga]Ga-NODAGA-E[(cRGDyK)]2 and [64Cu]Cu-DOTATATE PET Predict Improvement in Ischemic Cardiomyopathy.

An increasing number of patients are living with chronic ischemic cardiomyopathy (ICM) and/or heart failure. Treatment options and prognostic tools are lacking for many of these patients. Our aim was to investigate the prognostic value of imaging angiogenesis and macrophage activation via positron emission tomography (PET) in terms of functional improvement after cell therapy. Myocardial infarction was induced in rats. Animals were scanned with [18F]FDG PET and echocardiography after four weeks and randomized to allogeneic adipose tissue-derived stromal cells (ASCs, n = 18) or saline (n = 9). Angiogenesis and macrophage activation were assessed before and after treatment by [68Ga]Ga-RGD and [64Cu]Cu-DOTATATE. There was no overall effect of the treatment. Rats that improved left ventricular ejection fraction (LVEF) had higher uptake of both [68Ga]Ga-RGD and [64Cu]Cu-DOTATATE at follow-up (p = 0.006 and p = 0.008, respectively). The uptake of the two tracers correlated with each other (r = 0.683, p = 0.003 pre-treatment and r = 0.666, p = 0.004 post-treatment). SUVmax at follow-up could predict improvement in LVEF (p = 0.016 for [68Ga]Ga-RGD and p = 0.045 for [64Cu]Cu-DOTATATE). High uptake of [68Ga]Ga-RGD and [64Cu]Cu-DOTATATE PET after injection of ASCs or saline preceded improvement in LVEF. The use of these tracers could improve the monitoring of heart failure patients in treatment.

Danish phase II trial using adipose tissue derived mesenchymal stromal cells for patients with ischaemic heart failure.

AIMS: Patients suffering from chronic ischaemic heart failure with reduced left ventricular ejection fraction (HFrEF) have reduced quality-of-life, repetitive hospital admissions, and reduced life expectancy. Allogeneic cell therapy is currently investigated as a potential treatment option after initially encouraging results from clinical autologous and allogeneic trials in patients with HFrEF. We aimed to investigate the allogeneic Cardiology Stem Cell Centre Adipose tissue derived mesenchymal Stromal Cell product (CSCC_ASC) as an add-on therapy in patients with chronic HFrEF. METHODS AND RESULTS: This is a Danish multi-centre double-blinded placebo-controlled phase II study with direct intra-myocardial injections of allogeneic CSCC_ASC. A total of 81 HFrEF patients were included and randomized 2:1 to CSCC_ASC or placebo injections. The inclusion criteria were reduced left ventricular ejection fraction (LVEF ≤ 45%), New York Heart Association (NYHA) class II-III despite optimal anti-congestive heart failure medication and no further revascularization options. Injections of 0.3 mL CSCC_ASC (total cell dose 100 × 106 ASCs) (n = 54) or isotonic saline (n = 27) were performed into the viable myocardium in the border zone of infarcted tissue using the NOGA Myostar® catheter (Biological Delivery System, Cordis, Johnson & Johnson, USA). The primary endpoint, left ventricular end systolic volume (LVESV), was evaluated at 6-month follow-up. The safety was measured during a 3-years follow-up period. RESULTS: Mean age was 67.0 ± 9.0 years and 66.6 ± 8.1 years in the ASC and placebo groups, respectively. LVESV was unchanged from baseline to 6-month follow-up in the ASC (125.7 ± 68.8 mL and 126.3 ± 72.5 mL, P = 0.827) and placebo (134.6 ± 45.8 mL and 135.3 ± 49.6 mL, P = 0.855) group without any differences between the groups (0.0 mL (95% CI -9.1 to 9.0 mL, P = 0.992). Neither were there significant changes in left ventricular end diastolic volume or LVEF within the two groups or between groups -5.7 mL (95% CI -16.7 to 5.3 mL, P = 0.306) and -1.7% (95% CI -4.4. to 1.0, P = 0.212), respectively). NYHA classification and 6-min walk test did not alter significantly in the two groups (P > 0.05). The quality-of-life, total symptom, and overall summary score improved significantly only in the ASC group but not between groups. There were 24 serious adverse events (SAEs) in the ASC group and 11 SAEs in the placebo group without any significant differences between the two groups at 1-year follow-up. Kaplan-Meier plot using log-rank test of combined cardiac events showed an overall mean time to event of 30 ± 2 months in the ASC group and 29 ± 2 months in the placebo group without any differences between the groups during the 3 years follow-up period (P = 0.994). CONCLUSIONS: Intramyocardial CSCC_ASC injections in patients with chronic HFrEF were safe but did not improve myocardial function or structure, nor clinical symptoms.

Effect of allogeneic adipose tissue-derived mesenchymal stromal cell treatment in chronic ischaemic heart failure with reduced ejection fraction - the SCIENCE trial.

AIMS: The aim of the SCIENCE trial was to investigate whether a single treatment with direct intramyocardial injections of adipose tissue-derived mesenchymal stromal cells (CSCC_ASCs) was safe and improved cardiac function in patients with chronic ischaemic heart failure with reduced ejection fraction (HFrEF). METHODS AND RESULTS: The study was a European multicentre, double-blind, placebo-controlled phase II trial using allogeneic CSCC_ASCs from healthy donors or placebo (2:1 randomization). Main inclusion criteria were New York Heart Association (NYHA) class II-III, left ventricular ejection fraction (LVEF) <45%, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels >300 pg/ml. CSCC_ASCs or placebo (isotonic saline) were injected directly into viable myocardium. The primary endpoint was change in left ventricular end-systolic volume (LVESV) at 6-month follow-up measured by echocardiography. A total of 133 symptomatic HFrEF patients were included. The treatment was safe without any drug-related severe adverse events or difference in cardiac-related adverse events during a 3-year follow-up period. There were no significant differences between groups during follow-up in LVESV (0.3 ± 5.0 ml, p = 0.945), nor in secondary endpoints of left ventricular end-diastolic volume (-2.0 ± 6.0 ml, p = 0.736) and LVEF (-1.6 ± 1.0%, p = 0.119). The NYHA class improved slightly within the first year in both groups without any difference between groups. There were no changes in 6-min walk test, NT-proBNP, C-reactive protein or quality of life the first year in any groups. CONCLUSION: The SCIENCE trial demonstrated safety of intramyocardial allogeneic CSCC_ASC therapy in patients with chronic HFrEF. However, it was not possible to improve the pre-defined endpoints and induce restoration of cardiac function or clinical symptoms.

Functional in vitro models of the inhibitory effect of adipose tissue-derived stromal cells on lymphocyte proliferation: Improved sensitivity and quantification through flow cytometric analysis.

As the interest in cell-based therapies continue to increase, so does the need for assays detailing potency and providing platforms for identifying mechanisms of action. For most clinical implications of mesenchymal stromal cells, the immunomodulatory effect is crucial. While the suppressive potential on lymphocyte proliferation is well-described in literature, reproducible and standardized assays to document and quantify it varies from research group to research group and between methodologies. The aim of the present study was to utilize flowcytometry to quantify proliferation and identify measurements to increase the assay sensitivity to treatment with adipose tissue-derived stromal cells (ASC). Lymphocyte proliferation was induced by the unspecific mitogen phytohemagglutinin or by alloreactivity towards an irradiated donor in a mixed lymphocyte reaction. Addition of ASC did not change the composition of T cells, B cells, NK cells, NKT cell types considerably; likewise, no increases in proliferation were observed upon inclusion of ASC, demonstrating that ASC does not evoke an additive response. On the contrary, the suppressive effect of ASC was documented. By applying different gating strategies and curve fitting, the sensitivity was increased, and dose-response relationships established. Flow cytometric evaluation allows for more detailed identification of the lymphocytes affected by ASC and constitute a significant asset in future unraveling of modes and mechanisms of action, as well as quantification of potency.

Optimizing an immunomodulatory potency assay for Mesenchymal Stromal Cell.

The expeditious progress of Mesenchymal Stromal Cells (MSC) for therapeutic intervention calls for means to compare differences in potency of cell products. The differences may be attributed to innumerable sources including tissue origin, production methods, or even between batches. While the immunomodulatory potential of MSC is recognized and well-documented by an expansive body of evidence, the methodologies and findings vary markedly. In this study, we utilized flowcytometric analysis of lymphocyte proliferation based on cryopreserved peripheral blood mononuclear cells for quantification of the inhibitory effect of MSC. Technical aspects of fluorescent staining and cryopreservation of peripheral blood mononuclear cells were evaluated to obtain optimal results and increase feasibility. A range of common specific and unspecific mitogens was titrated to identify the conditions, in which the effects of Adipose tissue-derived Stromal Cells (ASC; a type of MSC) were most pronounced. Specific stimulation by antibody-mediated activation of CD3 and CD28 via TransAct and Dynabeads lead to substantial proliferation of lymphocytes, which was inhibited by ASC. These results were closely mirrored when applying unspecific stimulation in form of phytohemagglutinin (PHA), but not concanavalin A or pokeweed mitogen. The mixed lymphocyte reaction is a common assay which exploits alloreactivity between donors. While arguably more physiologic, the output of the assay often varies substantially, and the extent of proliferation is limited since the frequency of alloreactive cells is low, as opposed to the mitogens. To heighten the proliferative response and robustness, combinations of 2-5 donors were tested. Maximum proliferation was observed when combining 4 or more donors, which was efficiently suppressed by ASC. Several desirable and unfavorable traits can be attributed to the tested stimuli in the form of keywords. The importance of these traits should be scored on a laboratory-level to identify the ideal mitogen. In our case the ranking listed PHA as the most suited candidate. Developing robust assays is no trivial feat. By disclosing the full methodological framework in the present study, we hope to aid others in establishing functional metrics on the road to potency assays.

Adipose-derived stromal cells increase the formation of collagens through paracrine and juxtacrine mechanisms in a fibroblast co-culture model utilizing macromolecular crowding.

BACKGROUND: Adipose-derived stromal cells (ASCs) possess a multitude of regenerative capabilities, which include immunomodulation, angiogenesis, and stimulation of extracellular matrix (ECM) remodeling. However, the underlying mechanisms leading to ECM remodeling remain largely elusive and highlight the need for functional in vitro models for mode of action studies. Therefore, the purpose of this study was to develop an in vitro co-culture model to investigate the capabilities of ASCs to modulate fibroblasts and ECM. METHODS: An ECM in vitro model with ASCs and normal human dermal fibroblasts (NHDFs) was established utilizing macromolecular crowding, ascorbic acid, and TGF-ß stimulation. Paracrine and juxtacrine co-cultures were created using transwell inserts and cell cultures with direct cell-cell contacts. The cultures were screened using RT2 PCR Profiler Arrays; the protein levels of myofibroblast differentiation marker alpha smooth muscle actin (αSMA) and ECM remodeling enzymes were analyzed using western blot on cell lysates; the formation of collagen type I, III, VI, and fibronectin was investigated using ELISA on culture supernatants; and the deposition of collagens was analyzed using immunocytochemistry. RESULTS: TGF-ß stimulation of NHDF monocultures increased the expression of 18 transcripts relevant for ECM formation and remodeling, the protein levels of αSMA and matrix metalloproteinase-2 (MMP-2), the formation of collagen type I, III, VI, and fibronectin, and the deposition of collagen type I and VI and decreased the protein levels of MMP-14. Inclusion of ASCs in the ECM co-culture model increased the formation of collagen type I and III through paracrine mechanisms and the formation of collagen type VI through juxtacrine mechanisms. CONCLUSIONS: The co-culture model provides effective stimulation of NHDF monocultures by TGF-ß for enhanced formation and deposition of ECM. In the model, ASCs induce changes in ECM by increasing formation of collagen type I, III and VI. The obtained results could guide further investigations of ASCs' capabilities and underlying mechanisms related to ECM formation and remodeling.