The antiapoptotic effect of granulocyte colony-stimulating factor reduces infarct size and prevents heart failure development in rats

Granulocyte-colony stimulating factor ameliorates di-ethylhexyl phthalate-induced cardiac muscle injury via stem cells recruitment, Desmin protein regulation, antifibrotic and antiapoptotic mechanisms

Phthalates are common plasticizers present in medical-grade plastics and other everyday products. Di-ethylhexyl phthalate (DEHP) has been noted as a causative risk factor for the initiation and augmentation of cardiovascular functional disorders. G-CSF is a glycoprotein found in numerous tissues throughout the body and is currently applied in clinical practice and has been tested in congestive heart failure. We aimed to examine in depth the effect of DEHP on the histological and biochemical structure of the cardiac muscle in adult male albino rats and the mechanisms underlying the possible ameliorative effect of G-CSF. Forty-eight adult male albino rats were divided into control group, DEHP group, DEHP+ G-CSF group and DEHP-recovery group. We measured serum levels of aspartate aminotransferase (AST), creatine kinase MB isoenzyme (CK-MB) and lactate dehydrogenase (LDH). Left ventricular sections were processed for light and electron microscope examination, and immunohistochemical staining of Desmin, activated Caspase-3 and CD34. DEHP significantly increased enzyme levels, markedly distorted the normal architecture of cardiac muscle fibers, downregulated Desmin protein levels and enhanced fibrosis, and apoptosis. G-CSF treatment significantly decreased the enzyme levels compared to DEHP group. It enhanced CD34 positive stem cells recruitment to injured cardiac muscle, therefore improved the ultrastructural features of most cardiac muscle fibers via anti-fibrotic and anti-apoptotic effects in addition to increased Desmin protein expression levels. The recovery group showed partial improvement due to persistent DEHP effect. In conclusion, administration of G-CSF effectively corrected the histopathological, immunohistochemical and biochemical alterations in the cardiac muscle after DEHP administration by stem cells recruitment, Desmin protein regulation, antifibrotic and antiapoptotic mechanisms.

Interactions between Autophagy, Proinflammatory Cytokines, and Apoptosis in Neuropathic Pain: Granulocyte Colony Stimulating Factor as a Multipotent Therapy in Rats with Chronic Constriction Injury

Our previous studies have shown that early systemic granulocyte colony-stimulating factor (G-CSF) treatment can attenuate neuropathic pain in rats with chronic constriction injury (CCI) by modulating expression of different proinflammatory cytokines, microRNAs, and proteins. Besides the modulation of inflammatory mediators' expression, previous studies have also reported that G-CSF can modulate autophagic and apoptotic activity. Furthermore, both autophagy and apoptosis play important roles in chronic pain modulation. In this study, we evaluated the temporal interactions of autophagy, and apoptosis in the dorsal root ganglion (DRG) and injured sciatic nerve after G-CSF treatment in CCI rats. We studied the behaviors of CCI rats with or without G-CSF treatment and the various levels of autophagic, proinflammatory, and apoptotic proteins in injured sciatic nerves and DRG neurons at different time points using Western blot analysis and immunohistochemical methods. The results showed that G-CSF treatment upregulated autophagic protein expression in the early phase and suppressed apoptotic protein expression in the late phase after nerve injury. Thus, medication such as G-CSF can modulate autophagy, apoptosis, and different proinflammatory proteins in the injured sciatic nerve and DRG neurons, which have the potential to treat neuropathic pain. However, autophagy-mediated regulation of neuropathic pain is a time-dependent process. An increase in autophagic activity in the early phase before proinflammatory cytokines reach the threshold level to induce neuropathic pain can effectively alleviate further neuropathic pain development.

Multiple Progressive Thermopreconditioning Improves Cardiac Ischemia/Reperfusion-induced Left Ventricular Contractile Dysfunction and Structural Abnormality in Rat

BACKGROUND

Triple progressive thermopreconditioning (3PTP) may induce high Hsp-70 expression to maintain cardiac function. We suggest that 3PTP may reduce myocardial ischemia/reperfusion (I/R) injury during organ transplantation through Bag3/Hsp-70 mediated defense mechanisms.

METHODS

Male Wistar rats were divided into sham control group and 72 h after 3PTP in a 42°C water bath (3PTP) group. Rats underwent 60 min of ischemia by occlusion of the left anterior descending coronary artery followed by 240 min reperfusion. Hemodynamic parameters, including the electrocardiogram, microcirculation, heart rate, left ventricular end-diastolic pressure, maximal rate of rise (+dp/dt), and fall (-dp/dt) in the left ventricular pressure for index of contraction and relaxation were determined. Myocardial infarct size was evaluated by the Evans blue-2,3,5-triphenyltetrazolium chloride method. 3PTP-induced protective mechanisms were determined by Western blot and immunohistochemistry.

RESULTS

Cardiac I/R depressed cardiac microcirculation, induced S-T segment elevation, and R-R and P-R interval elongation increased infarct size associated with erythrocyte extravasation, leukocytes and macrophage/monocyte infiltration, granulocyte colony-stimulating factor, poly(ADP-ribose) polymerase 1 stain, and transferase-mediated dUTP-biotin nick end labeling positive cells. However, 3PTP evoked significant cardioprotection against I/R injury, characterized by the increased +dp/dt value and the decreased elevated left ventricular end-diastolic pressure, erythrocyte extravasation, leukocyte and macrophage/monocyte infiltration, granulocyte colony-stimulating factor expression, poly(ADP-ribose) polymerase 1 expression, transferase-mediated dUTP-biotin nick end labeling positive cells, and fragmentation and infarct area. In addition, 3PTP increased Hsp-70 and Bag3 expression and decreased Bax/Bcl-2 ratio, but did not affect the Beclin-1 and LC3-II/LC3-I ratio in the heart with I/R injury.

CONCLUSIONS

3PTP therapies may through Bag3 upregulation alleviate I/R injury-induced left ventricular structural deterioration and dysfunction.

Premature ventricular contractions as a side effect of filgrastim in a child with B-thalassaemia

Premature ventricular contractions are a rare side effect of filgrastim, reported mainly in elderly men. Here we report the case of a 9-year-old child with thalassaemia who developed frequent premature ventricular contractions after three doses of filgrastim were given for deferiprone-induced agranulocytosis. The arrhythmia resolved 3 weeks after discontinuation of filgrastim. Children treated with filgrastim should be carefully monitored for potentially serious arrhythmia.

Effect of granulocyte colony–stimulating factor on the cochlear nuclei after creation of a partial nerve lesion: an experimental study in rats

OBJECTIVE

The risk of injury of the cochlear nerve during angle (CPA) surgery is high. Granulocyte colony–stimulating factor (G-CSF) has been found in various experimental models of peripheral and CNS injury to have a neuroprotective effect by inhibiting apoptosis and inflammation. However, to the authors' knowledge, the influence of G-CSF on cochlear nerve regeneration has not been reported. This study investigated the neuroprotective effect of G-CSF after a partial cochlear nerve lesion in rats.

METHODS

A lesion of the right cochlear nerve in adult male Sprague-Dawley rats was created using a water-jet dissector with a pressure of 8 bar. In the first group (G-CSF-post), G-CSF was administrated on Days 1, 3, and 5 after the surgery. The second group (G-CSF-pre/post) was treated with G-CSF 1 day before and 1, 3, and 5 days after applying the nerve injury. The control group received sodium chloride after nerve injury at the various time points. Brainstem auditory evoked potentials (BAEPs) were measured directly before and after nerve injury and on Days 1 and 7 to evaluate the acoustic function of the cochlear nerve. The animals were sacrificed 1 week after the operation, and their brains were fixed in formalin. Nissl staining of the cochlear nuclei was performed, and histological sections were analyzed with a light microscope and an image-processing program. The numbers of neurons in the cochlear nuclei were assessed.

RESULTS

The values for Waves 2 and 4 of the BAEPs decreased abruptly in all 3 groups in the direct postoperative measurement. Although the amplitude in the control group did not recover, it increased in both treatment groups. According to 2-way ANOVA, groups treated with G-CSF had a significant increase in BAEP Wave II amplitudes on the right side (p = 0.0401) after the applied cochlear nerve injury. With respect to Wave IV, a trend toward better recovery in the G-CSF groups was found, but this difference did not reach statistical significance. In the histological analysis, higher numbers of neurons were found in the G-CSF groups. In the statistical analysis, the difference in the numbers of neurons between the control and G-CSF-post groups reached significance (p = 0.0086). The difference in the numbers of neurons between the control and G-CSF-pre/post groups and between the G-CSF-post and G-CSF-pre/post groups did not reach statistical significance.

CONCLUSIONS

The use of G-CSF improved the function of the eighth cranial nerve and protected cochlear nucleus cells from destruction after a controlled partial injury of the nerve. These findings might be relevant for surgery that involves CPA tumors. The use of G-CSF in patients with a lesion in the CPA might improve postoperative outcomes.

Implantation of a Poly-L-Lactide GCSF-Functionalized Scaffold in a Model of Chronic Myocardial Infarction

A previously developed poly-l-lactide scaffold releasing granulocyte colony-stimulating factor (PLLA/GCSF) was tested in a rabbit chronic model of myocardial infarction (MI) as a ventricular patch. Control groups were constituted by healthy, chronic MI and nonfunctionalized PLLA scaffold. PLLA-based electrospun scaffold efficiently integrated into a chronic infarcted myocardium. Functionalization of the biopolymer with GCSF led to increased fibroblast-like vimentin-positive cellular colonization and reduced inflammatory cell infiltration within the micrometric fiber mesh in comparison to nonfunctionalized scaffold; PLLA/GCSF polymer induced an angiogenetic process with a statistically significant increase in the number of neovessels compared to the nonfunctionalized scaffold; PLLA/GCSF implanted at the infarcted zone induced a reorganization of the ECM architecture leading to connective tissue deposition and scar remodeling. These findings were coupled with a reduction in end-systolic and end-diastolic volumes, indicating a preventive effect of the scaffold on ventricular dilation, and an improvement in cardiac performance.

The high-fat diet induces myocardial fibrosis in the metabolically healthy obese minipigs-The role of ER stress and oxidative stress

BACKGROUND

The cellular mechanisms of obesity-induced cardiomyopathy are multiple and not completely elucidated. The objective of this study was to differentiate two obesity-associated cardiomyopathy miniature pig models: one with the metabolic syndrome (MetS), and one with a metabolically healthy obesity (MHO). The cellular responses during the development of obesity-induced cardiomyopathy were investigated.

METHODS

Five-month-old Lee-Sung (MetS) and Lanyu (MHO) minipigs were made obese by feeding a high-fat diet (HFD) for 6 months.

RESULTS

Obese pigs exhibited a greater heart weight than control pigs. Interstitial and perivascular fibrosis developed in the myocardium of obese pigs. The HFD induced cardiac lipid accumulation and oxidative stress and also decreased the antioxidant defense in MetS pigs. This diet activated oxidative stress without changing cardiac antioxidant defense and lipid content in MHO pigs. The HFD upregulated the expression of Grp94, CHOP, caspase 12, p62, and LC3II, and increased the ratio of LC3II to LC3I in the left ventricle (LV) of MetS pigs. Compared to obese MetS pigs, less Grp94 and elevated CHOP expression was found in the obese MHO heart. The HFD did not change the ratio of LC3II to LC3I and p62 expression in obese MHO pigs. The obese MetS pigs had an extensive and greater inflammatory response in the plasma than the obese MHO pigs, which had a lesser and milder inflammation.

CONCLUSION

Oxidative stress and ER stress were involved in the progression of MHO-related cardiomyopathy. Inflammation, autophagy, ER stress, oxidative stress, and lipotoxicity participated in the pathological mechanism of MetS-related cardiomyopathy.

Attenuation of cardiac hypertrophy by G-CSF is associated with enhanced migration of bone marrow-derived cells

Granulocyte-colony stimulating factor (G-CSF) has been shown to promote mobilization of bone marrow-derived stem cells (BMCs) into the bloodstream associated with improved survival and cardiac function after myocardial infarction. Therefore, the aim of the present study was to investigate whether G-CSF is able to attenuate cardiac remodelling in a mouse model of pressure-induced LV hypertrophy focusing on mobilization and migration of BMCs. LV hypertrophy was induced by transverse aortic constriction (TAC) in C57BL/6J mice. Four weeks after TAC procedure. Mice were treated with G-CSF (100 μg/kg/day; Amgen Biologicals) for 2 weeks. The number of migrated BMCs in the heart was analysed by flow cytometry. mRNA expression and protein level of different growth factors in the myocardium were investigated by RT-PCR and ELISA. Functional analyses assessed by echocardiography and immunohistochemical analysis were performed 8 weeks after TAC procedure. G-CSF-treated animals revealed enhanced homing of VLA-4⁺ and c-kit⁺ BMCs associated with increased mRNA expression and protein level of the corresponding homing factors Vascular cell adhesion protein 1 and Stem cell factor in the hypertrophic myocardium. Functionally, G-CSF significantly preserved LV function after TAC procedure, which was associated with a significantly reduced area of fibrosis compared to control animals. Furthermore, G-CSF-treated animals revealed a significant improvement of survival after TAC procedure. In summary, G-CSF treatment preserves cardiac function and is able to diminish cardiac fibrosis after induction of LV hypertrophy associated with increased homing of VLA-4⁺ and c-kit⁺ BMCs and enhanced expression of their respective homing factors VCAM-1 and SCF.

Granulocyte-colony stimulating factor reduces cardiomyocyte apoptosis and ameliorates diastolic dysfunction in Otsuka Long-Evans Tokushima Fatty rats

BACKGROUND

In recent studies, granulocyte-colony stimulating factor (G-CSF) was shown to improve cardiac function in myocardial infarction and non-ischemic cardiomyopathies. The mechanisms of these beneficial effects of G-CSF in diabetic cardiomyopathy are not yet fully understood. Therefore, we investigated the mechanisms of action of G-CSF on diabetic cardiomyopathy in a rat model of type 2 diabetes.

METHODS

Seventeen-week-old OLETF (Otsuka Long Evans Tokushima Fatty) diabetic rats and LETO (Long Evans Tokushima Otuska) rats were randomized to treatment with 5 days of G-CSF (100 μg/kg/day) or with saline. Cardiac function was evaluated by serial echocardiography performed before and 4 weeks after treatment. We measured expression of the G-CSF receptor (GCSFR) and Bcl-2, as well as the extent of apoptosis in the myocardium.

RESULTS

G-CSF treatment significantly improved cardiac diastolic function in the serial echocardiography assessments. Expression of G-CSFR was down-regulated in the diabetic myocardium (0.03 ± 0.12 % vs. 1 ± 0.15 %, p < 0.05), and its expression was stimulated by G-CSF treatment (0.03 ± 0.12 % vs. 0.42 ± 0.06 %, p < 0.05). In addition, G-CSF treatment increased the expression of Bcl-2 in the diabetic myocardium (0.69 ± 0.06 % vs. 0.26 ± 0.11 %, p < 0.05), consistent with the reduced cardiomyocyte apoptosis (9.38 ± 0.67 % vs. 17.28 ± 2.16 %, p < 0.05).

CONCLUSIONS

Our results suggest that G-CSF might have a cardioprotective effect in diabetic cardiomyopathy through up-regulation of G-CSFR, attenuation of apoptosis by up-regulation of Bcl-2 expression, and glucose-lowering effect. Our findings support the therapeutic potential of G-CSF in diabetic cardiomyopathy.

Erythrocytic mobilization enhanced by the granulocyte colony-stimulating factor is associated with reduced anthrax-lethal-toxin-induced mortality in mice

Anthrax lethal toxin (LT), one of the primary virulence factors of Bacillus anthracis, causes anthrax-like symptoms and death in animals. Experiments have indicated that levels of erythrocytopenia and hypoxic stress are associated with disease severity after administering LT. In this study, the granulocyte colony-stimulating factor (G-CSF) was used as a therapeutic agent to ameliorate anthrax-LT- and spore-induced mortality in C57BL/6J mice. We demonstrated that G-CSF promoted the mobilization of mature erythrocytes to peripheral blood, resulting in a significantly faster recovery from erythrocytopenia. In addition, combined treatment using G-CSF and erythropoietin tended to ameliorate B. anthracis-spore-elicited mortality in mice. Although specific treatments against LT-mediated pathogenesis remain elusive, these results may be useful in developing feasible strategies to treat anthrax.

Vascular repair and regeneration as a therapeutic target for pulmonary arterial hypertension

The last decade has seen substantial changes in our understanding of the pathobiology of pulmonary arterial hypertension (PAH), a severe and devastating disease without curative treatment. It is now accepted that injury to the endothelial cells of the pulmonary arteries is central for the subsequent development of lumen-obliterative lung vascular lesions. A variety of circulating and lung-resident progenitor and stem cells likely contribute to vascular integrity, and evidence for the presence of cells expressing stem and progenitor cell markers is found inside and in the immediate vicinity of pulmonary vascular lesions in PAH. The currently available vasodilator therapies mainly target enhanced vasoconstriction in the lung circulation and help to maintain or improve right ventricular function, but do not treat pulmonary vascular remodeling, the underlying cause of the disease. Vascular gene therapy and cell therapy with progenitor and stem cells is a progressing field in the context of the development of novel treatment options for PAH, but the majority of the studies are currently performed at the level of preclinical studies in animal models. The current review provides an overview of the current knowledge on cell- and gene therapy-based approaches for vascular repair and regeneration in PAH.

Granulocyte colony-stimulating factor improves early remodeling in isoproterenol-induced cardiac injury in rats

BACKGROUND

Granulocyte colony-stimulating factor (G-CSF) has been used in some animal models and humans with well-established cardiovascular diseases. However, its effects in the initial stage of progressive non-ischemic heart failure are unknown.

METHODS

Wistar rats (260-300 g) were divided into three groups: control (without any intervention), ISO (150 mg/kg isoproterenol hydrochloride sc, once a day for two consecutive days), and ISO-GCSF (50 μg/kg/d G-CSF for 7 days beginning 24 h after the last administration of ISO). Echocardiography was performed at baseline and after 30 days of follow-up. Subsequently, animals were anesthetized for hemodynamic analysis. The left ventricle was removed for analysis of interstitial collagen deposition and cardiomyocyte hypertrophy.

RESULTS

Isoproterenol led to left ventricular dilation (control, 7.7 ± 0.14 mm; ISO, 8.7 ± 0.16 mm; ISO-GCSF 7.8 ± 0.09 mm; p < 0.05), myocardial fibrosis (control, 2.0 ± 0.18%; ISO, 9.1 ± 0.81%; ISO-GCSF 5.9 ± 0.58%; p < 0.05) and cardiomyocyte hypertrophy (control, 303 ± 10 μm(2); ISO, 356 ± 18 μm(2); ISO-GCSF 338 ± 11 μm(2); p < 0.05). However, G-CSF partially prevented collagen deposition and left ventricular enlargement, with a slight effect on hypertrophy. Characterizing a compensated stage of disease, hemodynamic analysis did not change.

CONCLUSION

G-CSF administered for 7 days was effective in preventing the onset of ventricular remodeling induced by high-dose isoproterenol with decreased collagen deposition and chamber preservation.

Bone marrow-derived cell mobilization by G-CSF to enhance osseointegration of bone substitute in high tibial osteotomy

PURPOSE

To evaluate granulocyte colony-stimulating factor (G-CSF) efficacy in accelerating bone regeneration following opening-wedge high tibial valgus osteotomy for genu varum.

METHODS

A phase II trial was conducted for evaluating the preoperative administration of G-CSF given at 10 μg/kg/day for 3 consecutive days with an additional half-dose 4 h before the opening-wedge high tibial valgus osteotomy. Overall, 12 patients (Group A) received G-CSF treatment, and the subsequent 12 patients (Group B) underwent surgery without G-CSF. The osteotomy gap was filled by a bone graft substitute. Bone marrow cell (BMC) mobilization was monitored by CD34+ve cell and clonogenic progenitor cell analysis. All patients underwent a clinical (Lysholm Knee Scale and SF-36) and radiographic evaluation preoperatively, as well as at given intervals postsurgery.

RESULTS

All patients completed the treatment program without major side effects; G-CSF was well tolerated. BMC mobilization occurred in all Group A patients, with median peak values of circulating CD34+ve cells of 110/μL (range 29-256). Circulating clonogenic progenitors paralleled CD34+ve cell levels. A significant improvement in Lysholm Knee Scale was recorded at follow-up in Group A compared to Group B. At the radiographic evaluation, there was a significant increase in osseointegration at the bone-graft junction in Group A at 1, 2, 3 and 6 months postsurgery compared to Group B. The computerized tomography scan of the grafted area at 2 months postsurgery showed no significant difference in the quality of the newly formed bone between the two Groups.

CONCLUSIONS

Although the limited number of patients does not allow firm conclusions, the study suggests that G-CSF can be safely administered preoperatively in subjects undergoing opening-wedge high tibial valgus osteotomy; in addition, the clinical, radiographic and CT monitoring indicate that G-CSF and/or mobilized BMCs may hasten bone graft substitute osseointegration.

LEVEL OF EVIDENCE

I.

Acute effects of granulocyte colony-stimulating factor on early ventricular arrhythmias after coronary occlusion in rats

Objectives:

To evaluate the acute effects of colony-stimulating factor (G-CSF) on ventricular arrhythmias after coronary occlusion in rats.

Materials and Methods:

Male Wistar rats (10 weeks) received G-CSF (100 μg.kg^-1) or vehicle. Thirty minutes later, animals were infarcted by coronary occlusion under artificial respiration. Electrocardiogram was monitored for 30 min to evaluate ventricular arrhythmias.

Results:

G-CSF treatment reduced the number of premature ventricular beats and the number and duration of ventricular tachycardia. The incidence of ventricular fibrillation was significantly reduced by G-CSF (MI-Cont: 11.2 ± 2.4 vs. MI-GCSF: 5.4 ± 1 events; P < 0.05). However, total duration of ventricular fibrillation was not altered (MI-Cont: 84 ± 16 vs. MI-GCSF: 76 ± 13 sec).

Conclusions:

Acute administration of G-CSF before coronary ligature in rats reduces the incidence of ventricular premature beats and ventricular tachycardia, suggesting a possible direct electrophysiological effect of this cytokine independently of its genomic effects. However, the data suggest that G-CSF treatment may affect the spontaneous recovery from ventricular fibrillation. Acute G-CSF administration acts directly on cardiac electrophysiology, different from chronic treatment.

Effects of granulocyte-colony stimulating factor (G-CSF) on diabetic cardiomyopathy in Otsuka Long-Evans Tokushima fatty rats

BACKGROUND

Diabetic cardiomyopathy (CMP) is a common and disabling disease in diabetic patients, however no effective treatments have been developed. Although granulocyte-colony stimulating factor (G-CSF) improves heart function in myocardial infarction, its effect on non-ischemic CMP such as diabetic CMP is unknown. In the present study, we investigated the effects of G-CSF on diabetic CMP in a rat model of type II diabetes.

METHODS

Twenty 7-week-old male Otsuka Long-Evans Tokushima Fatty (OLETF: a rat model of diabetes) rats and 10 male Long-Evans Tokushima Otsuka (LETO: normal controls) rats were used. All of the LETO and 8 OLETF rats were fed on tap water while the rest were fed on sucrose-containing water. After 10 weeks, saline or recombinant human G-CSF (100 μg/kg/day) was injected intraperitoneally for 5 days. Blood levels of glucose, total cholesterol and triglyceride, and Doppler echocardiograms for diastolic dysfunction were obtained just before and 4 weeks after the saline or G-CSF treatment. Light microscopy, electron microscopy (EM) and immunohistochemistry for transforming growth factor-β were employed to examine myocardial histology 4 weeks after the saline or G-CSF treatment.

RESULTS

Diastolic dysfunction developed at 17 weeks (before the saline or G-CSF treatment) in the OLETF rats whether or not they were fed sucrose water, but were more severe in those fed sucrose water. Four weeks after saline or G-CSF treatment, diastolic function had recovered in the G-CSF-treated group regardless of sucrose water feeding, and perivascular and/or interstitial fibrosis in the G-CSF-treated group had decreased significantly. TGF-β immunoreactivity in the interstitial and perivascular tissue was also reduced in the G-CSF-treated group, and EM studies revealed less severe disruption of myofilaments and mitochondrial cristae, and decreased collagen deposition.

CONCLUSIONS

G-CSF can ameliorate cardiac diastolic dysfunction and morphological damage, especially fibrosis of the myocardium, in OLETF rats with diabetic CMP.