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Background: Autologous progenitor cell therapy comprising granulocyte-colony stimulating factor (G-CSF) for mobilization of bone-marrow derived progenitor cells (BMPCs) into peripheral blood and inhibition of dipeptidylpeptidase-IV by sitagliptin for enhanced myocardial recruitment of circulating BMPCs has been shown to improve survival after acute myocardial infarction (MI) in preclinical studies. In the SITAGRAMI trial we found that during short-term follow-up G-CSF plus sitagliptin (GS) failed to show a beneficial effect on cardiac function and clinical events in patients with acute MI that underwent successful PCI. The objective of the present analysis was to assess the impact of GS versus placebo treatment on long-term clinical outcomes of the SITAGRAMI trial patient population., Methods: In the randomized, prospective, double-blind, placebo-controlled SITAGRAMI trial, 174 patients with acute MI were assigned to GS or placebo in a 1:1 ratio. The primary outcome for the present long-term analysis was the composite of death, MI or stroke on long-term follow-up., Results: The median [IQR] follow-up duration was 4.50 [3.56-5.95] years. The primary outcome occurred in 12.8% of patients assigned to placebo and 9.2% assigned to GS (HR 0.69, 95% CI 0.28-1.69; p=0.42). The incidence of the combined cardiovascular outcome was 47.7% in the placebo- and 41.4% in the GS-group (HR 0.75, 95% CI 0.48-1.18; p=0.21). Overall, there was no significant difference in MACCE rates between both treatment groups (p=0.41)., Conclusion: These long-term follow-up data indicate that GS therapy does not improve clinical outcomes of patients with acute MI., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Objective: In animal models, G-CSF based progenitor cell mobilization combined with a DPP4 inhibitor leads to increased homing of bone marrow derived progenitor cells to the injured myocardium via the SDF1/CXCR4 axis resulting in improved ejection fraction and survival after acute myocardial infarction (AMI)., Research Design and Methods: After successful revascularization in AMI, 174 patients were randomized 1:1 in a multi-centre, prospective, placebo-controlled, parallel group, double blind, phase III efficacy and safety trial to treatment with G-CSF and Sitagliptin (GS) or placebo. Diabetic and non-diabetic patients were included in our trial. The primary efficacy endpoint hierarchically combined global left and right ventricular ejection fraction changes from baseline to 6 months of follow-up (ΔLVEF, ΔRVEF), as determined by cardiac MRI., Results: At follow-up ΔLVEF as well as ΔRVEF did not differ between the GS and placebo group. Patients in the placebo group had a similar risk for a major adverse cardiac event within 12 months of follow-up as compared to patients under GS., Conclusion: Progenitor cell therapy comprising the use of G-CSF and Sitagliptin after successfully revascularized acute myocardial infarction fails to show a beneficial effect on cardiac function and clinical events after 12 months. (EudraCT: 2007-003,941-34; ClinicalTrials.gov: NCT00650143, funding: Heinz-Nixdorf foundation)., (Copyright © 2015. Published by Elsevier Ireland Ltd.)

Aims: Dual therapy comprising G-CSF for mobilization of bone marrow-derived progenitor cells (BMPCs), with simultaneous pharmacological inhibition of dipeptidylpeptidase-IV for enhanced myocardial recruitment of circulating BMPC via the SDF-1α/CXCR4-axis, has been shown to improve survival after acute myocardial infarction (AMI). Using an innovative method to provide non-invasive serial in vivo measurements and information on metabolic processes, we aimed to substantiate the possible effects of this therapeutic concept on cardiac remodelling after AMI using 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography (FDG-PET)., Methods and Results: AMI was induced in C57BL/6 mice by performing surgical ligation of the left anterior descending artery in these mice. Animals were then treated with granulocyte-colony stimulating factor + Sitagliptin (GS) or placebo for a duration of 5 days following AMI. From serial PET scans, we verified that the infarct size in GS-treated mice (n = 13) was significantly reduced at Day 30 after AMI when compared with the mice receiving placebo (n = 10). Analyses showed a normalized FDG uptake on Day 6 in GS-treated mice, indicating an attenuation of the cardiac inflammatory response to AMI in treated animals. Furthermore, flow cytometry showed a significant increase in the anti-inflammatory M2-macrophages subpopulation in GS-treated animals. In comparing GS treated with placebo animals, those receiving GS-therapy showed a reduction in myocardial hypertrophy and left ventricular dilatation, which indicates the beneficial effect of GS treatment on cardiac remodelling. Remarkably, flow cytometry and immunohistochemistry showed an increase of myocardial c-kit positive cells in treated mice (n = 12 in both groups)., Conclusion: Using the innovative method of micro-PET for non-invasive serial in vivo measurements of metabolic myocardial processes in mice, we were able to provide mechanistic evidence that GS therapy improves cardiac regeneration and reduces adverse remodelling after AMI., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.)

Background: Medical stimulation of endogenous progenitor cell circulation may serve as a new therapeutic tool for treatment of acute myocardial infarction. We analyzed the effects of antidiabetic gliptins plus GCSF (granulocyte colony stimulating factor) on myocardial regeneration after myocardial infarction in a mouse model., Methods and Results: After surgical LAD-ligation (left anterior descending artery), Sitagliptin/Vildagliptin was applied yielding sufficient blood levels verified by mass spectrometry and significantly reducing activity of dipeptidyl peptidase (DPP) IV. GCSF or saline was administered intraperitoneally for 6 days. We assessed stem cell mobilization and homing (flow cytometry), infarct size (histology), neovascularization and cellular proliferation (immunohistology), heart function (Millar tip catheterization) and survival (Kaplan-Meier-curves). Gliptins±GCSF administration increased mobilization and cardiac homing of bone-marrow derived stem cells by stabilization of cardiac SDF1 (stromal cell-derived factor). For Sitagliptin, it could be shown that resident cardiac stem cells were stimulated, neovascularization was enhanced and cardiac remodeling was reduced. These effects finally improved myocardial function and increased survival for both gliptins. Although gliptins as a mono therapy lead to remarkable effects in a dose dependent manner and were superior to G-CSF mono-therapy, dual application of GCSF and gliptins revealed the best results. Since both gliptins yielded comparable effects concerning stem cell homing, cardiac function and survival, we suggest a class-effect of DPP-IV-inhibitors., Conclusions: Thus, gliptins+GCSF and in high concentrations even as mono therapy have beneficial effects on cardiac regeneration after myocardial infarction beyond its anti-diabetic potential., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Aims: Parathyroid hormone (PTH) administration after myocardial infarction (MI) is known to attenuate ischaemic cardiomyopathy. This effect mainly resulted from an increase in mobilization and homing of CD34+/CD45+ cells into the ischaemic myocardium. PTH-related stem cell mobilization was shown to be related to endogenous granulocyte-colony stimulating factor (G-CSF) release. The aim of our study is to determine the role of G-CSF on the cardioprotective effects of PTH., Methods and Results: G-CSF +/+ (C57BL/6) and G-CSF -/- mice were treated with PTH for 6 days after inducing a MI. The myocardial homing factor stromal cell-derived factor-1 (SDF-1) was analysed on day 2 with enzyme-linked immunosorbent assay. Stem cell populations in peripheral blood and hearts were examined by FACS on days 6 and 2, respectively. Cardiac function and immunohistochemistry were investigated on day 6 and day 30. PTH treatment resulted in a significant increase in CD45+/CD34+ cells in peripheral blood in G-CSF +/+ but not in G-CSF -/- mice. However, a significant increase in SDF-1 and enhanced migration of CD45+/CD34+ cells into the ischaemic myocardium was revealed after PTH administration in both G-CSF +/+ and G-CSF -/- mice. Enhanced stem cell homing was associated with improved cardiac function and post-MI survival after PTH treatment. Furthermore, infarct size, wall thickness, and neovascularization showed a significant improvement in both groups 30 days after MI., Conclusion: The cardioprotective effects of PTH were shown to be independent of endogenous G-CSF release and therefore from stem cell mobilization. This puts more emphasis on the role of stem cell homing into ischaemic myocardium.

Aims: The aims of this trial were to investigate the effect of granulocyte colony-stimulating factor (G-CSF) on left-ventricular ejection fraction and event-free survival in patients suffering from sub-acute myocardial infarction (STEMI)., Methods: We enrolled 44 patients suffering from sub-acute STEMI with late revascularization achieved by percutaneous coronary intervention (PCI). Patients were randomized to receive either G-CSF (Filgrastim) at a dose of 10 μg/kg body weight/day subcutaneously or placebo. Changes of global and regional cardiac function from baseline (1 week after PCI) over 1 and 3 months to 12 months of follow-up were analyzed by magnetic resonance imaging., Results: Ejection fraction improved in G-CSF treated patients from 41.1±11.9% to 47.1±11.9% (3 months) and decreased slightly to 45.7±15.1% after 1 year. Ejection fraction also improved in the placebo group from 43.8±9.0% to 49.5±11.8% (3 months) and decreased slightly to 42.9±15.4% after 1 year (1 year MRI follow-up was performed in 23 out initial 44 patients). There was no significant difference between the two groups at any time point. Other parameters such as infarct size, myocardial perfusion, left ventricular end-diastolic and end-systolic volumes were not different between the two groups. Event-free survival of such as death, (re) myocardial infarction or acute coronary syndromes, coronary artery bypass grafting and target lesion revascularization was not significantly different between both groups., Conclusions: G-CSF administration after sub-acute STEMI is feasible and safe but does not improve myocardial function or survival when used as a single substance., (Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.)

Ischemic cardiomyopathy is one of the main causes of death, which may be prevented by stem cell-based therapies. SDF-1alpha is the major chemokine attracting stem cells to the heart. Since SDF-1alpha is cleaved and inactivated by CD26/dipeptidylpeptidase IV (DPP-IV), we established a therapeutic concept--applicable to ischemic disorders in general--by combining genetic and pharmacologic inhibition of DPP-IV with G-CSF-mediated stem cell mobilization after myocardial infarction in mice. This approach leads to (1) decreased myocardial DPP-IV activity, (2) increased myocardial homing of circulating CXCR-4+ stem cells, (3) reduced cardiac remodeling, and (4) improved heart function and survival. Indeed, CD26 depletion promoted posttranslational stabilization of active SDF-1alpha in heart lysates and preserved the cardiac SDF-1-CXCR4 homing axis. Therefore, we propose pharmacological DPP-IV inhibition and G-CSF-based stem cell mobilization as a therapeutic concept for future stem cell trials after myocardial infarction.

Objective: Granulocyte colony-stimulating factor (G-CSF) improves myocardial function after infarction in vivo. Placebo-controlled clinical studies failed to show beneficial effects on myocardial function. Recent data demonstrate that the time point of treatment initiation may be crucial for the efficacy of G-CSF. We investigated the influence of the timing of G-CSF treatment on myocardial function and perfusion in a subgroup study of the G-CSF-ST Elevation Myocardial Infarction trial., Materials and Methods: Patients with late revascularized myocardial infarction (n = 44) were treated with either G-CSF or placebo over 5 days after successful percutaneous coronary intervention (PCI). Of the G-CSF group, 13 patients had received G-CSF early treatment started within 24 hours after PCI (mean: 16 +/- 6 hours). In 10 patients, G-CSF was initiated late (>24 hours after PCI, mean: 49 +/- 26 hours). Global and regional myocardial function and perfusion were assessed from baseline to 3 months after PCI using magnetic resonance imaging in 37 patients who completed magnetic resonance follow-up., Results: G-CSF was safe when used early or late after PCI. Early G-CSF administration resulted in significantly improved perfusion at rest 1 month after PCI when compared to placebo (Up-slope, signal intensity 1.2 [0.4-1.8] vs 0.6 [0.1-1.3], p = 0.03). Timing of G-CSF had no influence on global and regional function., Conclusion: This post-hoc analysis indicates that timing of G-CSF after myocardial infarction does not improve myocardial function but myocardial perfusion if the cytokine is given early. This urges the need to investigate alternative dosage regimens or combination with novel therapeutics promoting mobilization and homing.

Objectives: The purpose of this investigator-driven, prospective, randomized, double-blinded, placebo-controlled phase II study was to compare the effects of granulocyte colony-stimulating factor (G-CSF) on the improvement of myocardial function in patients undergoing delayed percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI)., Background: Experimental and early clinical studies suggest that transplantation of stem cells improves cardiac regeneration and neovascularization after acute myocardial infarction. Most investigators have utilized either a direct injection or intracoronary infusion of bone marrow-derived cells, but early cytokine-mediated mobilization of stem cells has been reported to show similar improvement in cardiac function., Methods: Forty-four patients with late revascularized subacute STEMI were treated either with G-CSF or placebo over 5 days after successful PCI. Primary end points were change of global and regional myocardial function from baseline (1 week after PCI) to 3 months after PCI assessed by magnetic resonance imaging (MRI). Secondary end points consisted of characterization of mobilized stem cell populations, assessment of safety parameters up to 12 months including 6-month angiography, as well as myocardial perfusion assessed by MRI., Results: Global myocardial function from baseline (1 week after PCI) to 3 months improved in both groups, but G-CSF was not superior to placebo (Delta(ejection fraction) 6.2 +/- 9.0 vs. 5.3 +/- 9.8%, p = 0.77). A slight but non-significant improvement of regional function occurred in both groups. Granulocyte colony-stimulating factor resulted in mobilization of endothelial progenitor cell populations and was well tolerated with a similar rate of target lesion revascularization from in-stent restenosis. In both groups major adverse cardiovascular events occurred in a comparable frequency. Granulocyte colony-stimulating factor resulted in significant improvement of myocardial perfusion 1 week and 1 month after PCI., Conclusions: Granulocyte colony-stimulating factor treatment after PCI in subacute STEMI is feasible and relatively safe. However, patients do not benefit from G-CSF when PCI is performed late. Granulocyte colony-stimulating factor results in improved myocardial perfusion of the infarcted area, which may reflect enhanced neovascularization.