G-CSF therapy with mobilization of bone marrow stem cells for myocardial recovery after acute myocardial infarction--a relevant treatment?

MSCs transplantation with application of G-CSF reduces apoptosis or increases VEGF in rabbit model of myocardial infarction

The purpose of this study was to test whether mesenchymal stem cells (MSCs) transplantation with application of granulocyte colony-stimulating factor (G-CSF) would have beneficial effects on damaged heart in a rabbit model of myocardial infarction (MI). MI was created by ligation of the left anterior descending coronary artery. After induction of MI, 40 New Zealand white rabbits were randomly divided into 8 groups: (1) MSCs injection at 3 days after MI; (2) G-CSF injection at 3 days after MI; (3) MSCs + G-CSF (20 u/kg/day) injection at 3 days after MI; (4) PBS injection at 3 days after MI; (5) MSCs injection at 7 days after MI; (6) G-CSF injection at 7 days after MI; (7) MSCs + G-CSF (20 u/kg/day) injection 7 days after MI; and (8) PBS injection 7 days after MI. TUNEL analysis showed that the apoptotic cells were distributed in the marginal area of MI. In both 3 and 7 days after MI groups, there were less apoptotic cells in the MSCs and MSCs + G-CSF groups as compared with the PBS group (P < 0.05). However, no decrease in apoptosis was observed in the G-CSF only group (P > 0.05). Immunohistochemistry analysis demonstrated that the expression level of vascular endothelial growth factor was higher in the MSCs, MSCs + G-CSF and G-CSF groups as compared with the PBS group. The present study demonstrated a beneficial effect of MSCs transplantation with application of G-CSF in the treatment of rabbit MI.

Statins and stem cell modulation

Stem cell-based therapy is a promising option for the treatment of ischemic heart diseases. As to a successful stem cell-based therapy, one of the most important issues is that the stable engraftment and survival of implanted stem cells in cardiac microenvironment. There are evidences suggest that pharmacological treatment devoted to regulate stem cell function might represent a potential new therapeutic strategy and are drawing nearer to becoming a part of treatment in clinical settings. Statins could exert cholesterol-independent or pleiotropic effects to cardiovascular system. Recent studies have shown that statins could modulate the biological characteristics and function of various stem cells, thus could be an effective method to facilitate stem cell therapy. This review will focus on statins and their modulation effects on various stem cells.

The effect of G-CSF on F-actin reorganization in HL-60 and K562 cell lines

The aim of this investigation was to show the influence of G-CSF (G-CSF) on the F-actin cytoskeleton and the morphology of G-CSFR-proficient HL-60 and G-CSFR-deficient K562 cell lines. In the present study, we show changes in F-actin distribution in HL-60 cells after treatment with 5 and 10 ng/ml concentration of G-CSF but also changes in the organization and fluorescence intensity of F-actin in the K562 cell line. After treatment of HL-60 cells with 5 ng/ml concentration of G-CSF we observed an increase in F-actin levels. Additionally, a higher labeling of nuclear F-actin under TEM was observed. Moreover, changes in the cell cycle indicate cell differentiation. On the other hand, in the K562 cell line we observed an increase in the percentage sub-G1 cells following treatment with both concentration of G-CSF. Furthermore, an increase in the percentage of late apoptotic cells after G-CSF treatment was observed. A statistically significant difference in the cytoplasmic F-actin levels was not detected, but nuclear levels were decreased. In conclusion, we suggest that the G-CSF-based reorganization of actin filaments in HL-60 cells is involved in the differentiation process. Moreover, we suggest that the G-CSF-induced changes observed in K562 cells are associated with a G-CSF receptor-independent pathway or its binding to other similar receptors.

Endothelial and cardiac progenitors: boosting, conditioning and (re)programming for cardiovascular repair

Preclinical studies performed in cell culture and animal systems have shown the outstanding ability of stem cells to repair ischemic heart and lower limbs by promoting the formation of new blood vessels and new myocytes. In contrast, clinical studies of stem cell administration in patients with myocardial ischemia have revealed only modest, although promising, results. Basic investigations have shown the feasibility of adult cells reprogramming into pluripotent cells by defined factors, thus opening the way to the devise of protocols to ex vivo derive virtually unexhausted cellular pools. In contrast, cellular and molecular studies have indicated that risk factors limit adult-derived stem cell survival, proliferation and engraftment in ischemic tissues. The use of fully reprogrammed cells raises safety concerns; therefore, adult cells remain a primary option for clinicians interested in therapeutic cardiovascular repair. Pharmacologic approaches have been devised to restore the cardiovascular repair ability of failing progenitors from patients at risk. In the present contribution, the most advanced pharmacologic approaches to (re)program, boost, and condition endothelial and cardiac progenitor cells to enhance cardiovascular regeneration are discussed.

Plasma YKL-40 and recovery of left ventricular function after acute myocardial infarction

BACKGROUND

Plasma YKL-40 is increased early in patients with ST-elevation myocardial infarction (STEMI). It is not known whether plasma YKL-40 is related to infarct size and recovery of ventricular function after primary percutaneous coronary intervention (PCI) of STEMI and whether granulocyte colony-stimulating factor (G-CSF) therapy influence plasma YKL-40 concentration.

MATERIALS AND METHODS

A total of 72 patients (age: 56 +/- 9 years (mean +/- SD), 56 men and 16 women) with STEMI treated with PCI were included in a double-blind, randomized, placebo-controlled trial with subcutaneous G-CSF or placebo injections from day 1 to 7 after the STEMI. Plasma YKL-40, high-sensitivity C-reactive protein (hs-CRP) and CK-MB concentrations were measured at baseline and during the first month. Infarct size and left ventricular ejection fraction (LVEF) were measured by magnetic resonance imaging at baseline and after 6 months.

RESULTS

Baseline plasma YKL-40 was increased (median 92 microg/L) compared to healthy subjects (median 34 microg/L, p <0.001). In the placebo group hs-CRP and YKL-40 correlated at baseline (p = 0.04) and day 3 (p = 0.01), but not at day 7 and 30. Moreover, YKL-40 correlated negatively to LVEF recovery (p = 0.04) but not infarct size. G-CSF injections increased YKL-40 compared to placebo (p <0.001), but were not associated with infarct size or LVEF recovery.

CONCLUSION

Plasma YKL-40 was significantly increased in STEMI patients at admission and G-CSF treatment caused a further increase in YKL-40. Plasma YKL-40 may be an indirect marker of LVEF recovery, independent of hs-CRP, and higher plasma YKL-40 indicates a lower recovery.

Granulocyte colony-stimulating factor (G-CSF) depresses angiogenesis in vivo and in vitro: implications for sourcing cells for vascular regeneration therapy

SUMMARY BACKGROUND

The most common source of hematopoietic progenitor cells (HPCs) for hematopoietic reconstitution comprises granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood stem cells (PBSCs). It has been proposed that endothelial progenitor cells (EPCs) share precursors with HPCs, and that EPC release may accompany HPC mobilization to the circulation following G-CSF administration.

OBJECTIVE

To investigate EPC activity following HPC mobilization, and the direct effects of exogenous G-CSF administration on human umbilical vein endothelial cells (HUVECs) and endothelial outgrowth cells (EOCs), using in vitro and in vivo correlates of angiogenesis.

PATIENTS/METHODS

Heparinized venous blood samples were collected from healthy volunteers and from cord blood at parturition. G-CSF-mobilized samples were collected before administration, at apheresis harvest, and at follow-up. PBSCs were phenotyped by flow cytometry, and cultured in standard colony-forming unit (CFU)-EPC and EOC assays. The effect of exogenous G-CSF was investigated by addition of it to HUVECs and EOCs in standard tubule formation and aortic ring assays, and in an in vivo sponge implantation model.

RESULTS

Our data show that G-CSF mobilization of PBSCs produces a profound, reversible depression of circulating CFU-EPCs. Furthermore, G-CSF administration did not mobilize CD34+CD133- cells, which include precursors of EOCs. No EOCs were cultured from any mobilized PBSCs studied. Exogenous G-CSF inhibited CFU-EPC generation, HUVEC and EOC tubule formation, microvessel outgrowth, and implanted sponge vascularization in mice.

CONCLUSIONS

G-CSF administration depresses both endothelial cell angiogenesis and monocyte proangiogenic activity, and we suggest that any angiogenic benefit observed following implantation of cells mobilized by G-CSF may come only from a paracrine effect from HPCs.

Effects of granulocyte-colony-stimulating factor on progenitor cell mobilization and heart perfusion and function in normal mice

BACKGROUND AIMS

Mobilization of stem cells and progenitor cells from the bone marrow (BM) into the peripheral blood (PB) by granulocyte-colony-stimulating factor (G-CSF) is being investigated for cardiac regeneration in ischemic heart disease. However, hematopoietic (HPC), mesenchymal (MPC) and endothelial (EPC) progenitor mobilization have not been optimized and the effect of G-CSF on myocardial perfusion and cardiac function in a normal heart has never been studied.

METHODS

Normal mice were injected daily for 1-10 days with subcutaneous recombinant human G-CSF. PB and BM were evaluated for HPC and EPC by flow cytometry and HPC and MPC by hematopoietic (CFU-GM) and mesenchymal (CFU-F) colony assays. Echocardiography, microSPECT imaging, cardiac catheterization and immunohistochemistry were performed in mice treated for 10 days.

RESULTS

HPC and CFU-GM in PB peaked after 2 days, CFU-F after 4 days and EPC after 3 days. Thereafter, while HPC temporally decreased before showing a second peak, EPC remained detectable only at low levels. In BM, hematopoietic stem cells (HSC) and CFU-GM did not increase much overall but peaked twice on days 2 and 7. EPC (peak on day 7) production increased in the BM, but CFU-F formation declined considerably after day 2. G-CSF enhanced myocardial perfusion and vascularization but impaired hemodynamic performance of the heart through apparently increased ventricular wall rigidity.

CONCLUSIONS

G-CSF induces the mobilization of HPC, EPC and CFU-F progenitors in PB according to very different patterns, and has a significant impact on perfusion and function of the normal heart.

Current perspective of pathophysiological and interventional effects on endothelial progenitor cell biology: focus on PI3K/AKT/eNOS pathway

For more than a decade, endothelial progenitor cells (EPCs) have been implicated in cardiovascular homeostasis. EPCs are believed to reside within the bone marrow in close contact with surrounding stromal cells, and, under stimulation of pro-inflammatory cytokines, EPCs are mobilized out of the bone marrow. Hereafter circulating EPCs home to peripheral tissues, undergoing further proliferation and differentiation. Under certain pathophysiologic conditions this process seems to be blunted, resulting in a reduced capacity of EPCs to engage in vasculogenesis at sites of endothelial injury or tissue ischemia. In this review, we focus on the effects of traditional cardiovascular risk factors on EPC biology and we explore whether pharmacological, dietary and lifestyle interventions can favorably restore EPC mobilization, differentiation, homing and angiogenic properties. Because the PI3K/Akt/eNOS pathway plays a pivotal role in the process of EPC mobilization, migration and homing, we specifically emphasize the involvement of PI3K, Akt and eNOS in EPC biology under these different (patho)physiologic conditions. (Pre)clinically used drugs or lifestyle interventions that have been shown to ameliorate EPC biology are reviewed. These treatment strategies remain attractive targets to restore the regenerative capacity of EPCs in cardiovascular diseases.

Marrow cell infusion attenuates vascular remodeling in a murine model of monocrotaline-induced pulmonary hypertension

There have been reports of marrow cells converting into pulmonary epithelial cells after marrow transplantation in irradiated mice. We evaluated the impact of whole bone marrow (WBM) infusion in mice, with or without total body irradiation (TBI), treated with saline or monocrotaline (MCT), which induces pulmonary hypertension (PH). C57BL/6 mice were injected with MCT or saline weekly for 4 weeks. Cohorts were then infused with saline vehicle (vehicle) or WBM from C57BL/-Tg(UBC-GFP)30Scha/J mice, with or without previous TBI (WBM or WBM/TBI). Four weeks later, right ventricular peak pressures (RVPP), right ventricular free wall-to-body weight ratios (RV/BW), and pulmonary vessel wall thickness-to-blood vessel diameter ratios (PVWT/D) were determined. WBM infusion and WBM following TBI induced increases in RVPP and RV/BW in saline-treated mice, while only TBI-exposed mice showed additional increases in PVWT/D. MCT increased RVPP, RV/BW, and PVWT/D in mice given vehicle or WBM alone, but not in mice given WBM/TBI. RVPP and RV/BW were not significantly lower in MCT mice given WBM/TBI than in MCT mice treated with vehicle, but MCT-treated mice given WBM or TBI/WBM had significantly lower PVWT/D compared to MCT-treated mice given saline vehicle. No donor WBM-derived pulmonary vascular cells were detected, suggesting that the observed effects of WBM infusion may be due to paracrine effects separate from cell conversions. The observation of PH after marrow infusion suggests an additional mechanism for lung toxicity seen in marrow transplantation. In conclusion, WBM alone appears to increase RVPP and RV/BW in normal mice but the combination of WBM and TBI attenuates MCT-induced PH.

Microvascular reactivity and inflammatory cytokines in painful and painless peripheral diabetic neuropathy

OBJECTIVE

We investigated the association between inflammation, microvascular reactivity, and the development of peripheral diabetic neuropathy.

RESEARCH DESIGN AND METHODS

We studied three groups: 55 healthy control subjects, 80 nonneuropathic patients, and 77 neuropathic diabetic patients. We also subdivided the neuropathic patients into a subgroup of 31 subjects with painless neuropathy and 46 with painful neuropathy. We measured the foot skin endothelium-dependent and -independent vasodilation, the nerve axon reflex-related vasodilation (NARV), and inflammatory cytokines and biochemical markers of endothelial function.

RESULTS

The endothelium-dependent and -independent vasodilation and NARV were lower in the neuropathic group (P < 0.05). NARV was further reduced in the subgroup of painless neuropathy when compared to painful neuropathy (P < 0.05). Compared to the other two groups, the neuropathic group also had higher serum levels of PDGF AA/BB (P < 0.05), RANTES (P < 0.01), leptin (P < 0.0001), osteoprotegerin (P < 0.01), G-CSF (P < 0.05), sE-Selectin (P < 0.01), sICAM (P < 0.0001), sVCAM (P < 0.001), CRP (P < 0.0001), TNFalpha (P < 0.05), and fibrinogen (P < 0.05). Patients with painful neuropathy had higher sICAM-1 (P < 0.05) and CRP levels (P < 0.01) when compared to painless neuropathy. No major changes in the above results were observed in 78 diabetic patients who were seen for a second visit 21 months after the first visit.

CONCLUSIONS

Peripheral diabetic neuropathy is associated with increased biochemical markers of inflammation and endothelial dysfunction. Painful neuropathy is associated with further increase in inflammation and markers of endothelial dysfunction and preservation of the nerve axon reflex.

Timing of granulocyte-colony stimulating factor treatment after acute myocardial infarction and recovery of left ventricular function: results from the STEMMI trial

BACKGROUND

Granulocyte-colony stimulating factor (G-CSF) therapy after ST-elevation myocardial infarction (STEMI) have not demonstrated impact on systolic recovery compared to placebo. However, recent studies suggest that timing of G-CSF therapy is crucial.

METHODS

Timing of G-CSF treatment was analyzed in the STEMMI MRI subpopulation including 54 patients with STEMI treated with primary percutaneous coronary intervention (PCI) <12 h after symptom onset. Patients were randomized to double blind treatment with G-CSF (10 microg/kg/day) or placebo. Treatment was initiated from 17 to 65 h (mean 30) after PCI. Left ventricular ejection fraction (LVEF) was evaluated with MRI.

RESULTS

Recovery of LVEF from baseline to 6 months was not associated with time from PCI to G-CSF. An identical improvement in LVEF was found in the placebo group and the G-CSF group (p=0.8). There was no correlation between time from PCI to G-CSF and maximum plasma concentration of CD34+ cells (r=-0.3, p=0.1). Similar results were found from data on recovery of the infarction size and change in the systolic wall thickening.

CONCLUSIONS

In the time window from 17 to 65 h after STEMI treated with PCI, the timing of G-CSF treatment does not seem to affect the recovery of LVEF. It remains to be determined if very early, or very late G-CSF treatment might be effective.