Administration Of Granulocyte-macrophage Colony-stimulating Factor Research Articles

ЛЕГЕНЕВИЙ АЛЬВЕОЛЯРНИЙ ПРОТЕЇНОЗ: ВИПАДОК СУБТОТАЛЬНОГО УРАЖЕННЯ ПАРЕНХІМИ ЛЕГЕНЬ)

Pulmonary alveolar proteinosis (PAP) is a rare pulmonary disease, characterized by the intraalveolar accumulation of surfactant-like lipoprotein substance. There are three forms of the disease: autoimmune (formerly known as idiopathic), secondary and congenital PAP. The disturbances of surfactant metabolism (protein-lipoid complex secreted by type II pneumocytes) play the crucial role in the development of the disease. Surfactant decreases a surface tension of alveoli and prevents its collapse at the end of the expiration and takes part in protection against infections as well. Surfactant is inactivated through the transformation into the surface-inactive aggregates, which are mainly absorbed by type II pneumocytes. The rest of surfactant are catabolized by alveolar macrophages (AM). This process is regulated by cytokines, especially granulocyte-macrophage colony-stimulating factor (GM-CSF) being the most important of them. Disturbances of interrelation between GM-CSF and cellular receptors blocks the signals to effector cells for surfactant deactivation. This is resulted in excessive accumulation of surfactant in alveoli. General lavage of the lung is a standard method of symptomatic management of PAP. Contemporary pathogenesis treatment uses two approaches — increasing the clearance of surfactant by means of exogenous GM-CSF administration and decreasing the level of GM-CSF antibodies using the rituximab and plasmapheresis. Due to the use of broncho-alveolar lavage (BAL) 5-year survival rate of th patients reaches 95 %. The mortality depends on the area of lung lesion and reversely correlated with the timely diagnosis and treatment. We report the case of subtotal lung parenchyma lesion associated with severe respiratory failure in 46 years old patient. Three series of BAL (5 procedures in each with 1-2 months interval) were performed using the limited volume of lavage fluid due to the severity of the patient’s condition. The results was an improvement of clinical condition, resolution of respiratory failure, significant reduction of the size of the lesions, improved lung transparency on CT scan, restoration of lung diffusion and total lung capacity. Conclusion. Therapeutic BAL is an effective method of PAP management. The outcome of clinical case presented and our many years experience confirm not only the effectiveness of conventional BAL with reduced lavage volume application but also a safety of fiberoptic bronchoscopy, especially in patients with subtotal involvement of lung parenchyma. Key words: pulmonary alveolar proteinosis, subtotal pulmonary parenchyma involvement, pulmonary bronchoalveolar lavage, efficiency.

Administration of granulocyte-macrophage colony-stimulating factor enhanced chimeric antigen receptor T-cell expansion and cellular immunity recovery without inducing cytokine release syndrome.

Neutropenia and cytokine release syndrome (CRS) are two major toxicities of chimeric antigen receptor (CAR)-T cell therapy. Granulocyte-macrophage colony-stimulating factor (GM-CSF) is an ideal candidate treatment for neutropenia except for its potential aggravation of CRS. We hypothesized that the optimal timing of supplemental with GM-CSF in a shortage of host immunity and CAR T-cell was chosen as avoidance of CRS. In the study we evaluated the safety and efficacy of GM-CSF intervention post-CAR T-cell therapy while circulating CAR T-cell declined. Nine patients received GM-CSF therapy who displayed moderate neutropenia with absolute neutrophil counts (ANC) < 1,500 cells/mm3 with concomitant declination of circulating CAR T-cell. The median duration of GM-CSF intervention was 15 days (4-30). CAR T-cell expansion was observed in peripheral blood (PB) of seven patients (7/9). The median baseline and peak CAR T cells count in PB of the seven patients with CAR T-cell expansion were 0.85 × 106/L (0-50.9) and 6.06 × 106/L (1.43-112.55). And the peaks of CAR T-cell levels in PB appeared in day 7 (2-11) following the initiation of GM-CSF administration with increases of 2.84 × 106/L (0.38-61.65). Also, increased white blood cells in PB were observed in all patients. The median onset and duration time of WBC recovery were 9 (1-14) and 17 (3-53) days. Moreover, the increment of WBC, neutrophil, lymphocyte and CD3-CD16 + CD56 + natural killer cell in PB was observed. In addition, no CRS or fatal infection occurred during GM-CSF treatment. This study provides evidence for the clinical feasibility of combining CAR T-cell therapy with the GM-CSF to treat neutropenia patients with concomitant declination of circulating CAR T-cell.

The Stimulation of Macrophages by Systematical Administration of GM-CSF Can Accelerate Adult Wound Healing Process.

Skin wound repair remains a major challenge in clinical care, and various strategies have been employed to improve the repair process. Recently, it has been reported that macrophages are important for the regeneration of various tissues and organs. However, their influence on wound repair is unclear. Here, we aimed to explore whether macrophages would participate in the wound healing process and to explore new possibilities of treatment for skin defects. We firstly created a mouse full-thickness skin defect model to observe the distribution of macrophages in the regenerating tissue and then detected the influence of macrophages on skin defect repair in both macrophage-depletion and macrophage-mobilization models. We found that the number of macrophages increased significantly after skin defect and persisted during the process of wound repair. The regeneration process was significantly prolonged in macrophage-depleted animals. RT-qPCR and ELISA assays further demonstrated that the expression of growth factors was perturbed in the regenerating tissue. The activation of macrophages by granulocyte-macrophage colony-stimulating factor (GM-CSF) injection could significantly improve wound healing, accompanied with an upregulation of the expression of various growth factors. In conclusion, the current study demonstrated that macrophages are critical for skin regeneration and that GM-CSF exhibited therapeutic potential for wound healing.

Experience with Treatment of Pulmonary Alveolar Proteinosis from a Tertiary Care Centre in North India

Pulmonary alveolar proteinosis (PAP) is a disorder characterised by accumulation of lipids and proteins in the alveoli, with the resultant symptoms ranging from indolent subclinical disease to progressive respiratory failure. We retrospectively studied five patients with PAP managed at our center between January 2007 and April 2010, with whole lung lavage (WLL) and/or subcutaneous granulocyte macrophage-colony stimulating factor (GM-CSF) therapy. Patients undergoing WLL under general anaesthesia were supplemented with three months of GM-CSF therapy. Pre- and post-lavage symptom assessment was performed with a 10-point, symptom-based visual analogue scale. Their mean age was 37.6-7.0 years; there were four males. Diagnosis of PAP [idiopathic (n=3); secondary to Nocardia (n=1)] was established by surgical lung biopsy in four patients who presented with respiratory failure. Three patients with idiopathic PAP (n=3) were treated with a combination of GM-CSF and WLL; one patient with secondary PAP was treated with antibiotics alone. In another patient transbronchial lung biopsy was used to diagnose PAP and GM-CSF alone was administered. All patients were followed up for a median period of two years (range 0.5-3 years). Significant improvement was achieved in all the patients with therapeutic WLL and/or GM-CSF. Whole lung lavage appeared to be an effective and safe therapy in patients with PAP. Efficacy of simultaneous administration of GM-CSF and WLL in the treatment of PAP merits further study.

A Placebo-Controlled Study of Recombinant Human Granulocyte-Macrophage Colony-Stimulating Factor Administered During and After Induction Treatment for De Novo Acute Myelogenous Leukemia in Elderly Patients

The complete remission (CR) rate after intensive chemotherapy for acute myelogenous leukemia (AML) remains low in elderly patients, mainly because of a higher infectious mortality rate related to neutropenia and an increased incidence of adverse prognostic factors. Granulocyte-macrophage colony-stimulating factor (GM-CSF) has been shown to potentially recruit leukemic blasts into cell cycle and improve cytotoxic effects when given during chemotherapy, and to shorten the duration of neutropenia when administered after chemotherapy. Two hundred forty patients aged 55 to 75 years who had newly diagnosed AML were randomly assigned to receive placebo or Escherichia coli-derived GM-CSF (5 micrograms/kg/d by 6-hour intravenous infusion) starting during induction chemotherapy on day 1 and continued through and after chemotherapy until recovery of neutrophils, or evidence of regrowth of leukemia, or up to day 28. Induction chemotherapy consisted of idarubicin (8 mg/m2/d on days 1 to 5) and cytarabine (100 mg/m2/d on days 1 to 7). The study drug was not administered subsequent to the induction course. Patients who achieved a CR received continuous maintenance therapy for 1 year with four quarterly reinduction courses; in the 55- to 64-year age subgroup, patients were randomly assigned to receive or not a consolidation course before maintenance therapy. The CR rate was similar in the GM-CSF and placebo groups (63% and 60.5%, respectively; P = .79). The mortality, rate of resistant disease, and rate of regrowth of leukemia were also similar in both groups. The time to neutrophil recovery was shorter in patients who received GM-CSF (24 v 29 days; P = .0001), but the incidence and characteristics of infectious events were not different. The 2-year disease-free survival (DFS) rate was significantly improved in the GM-CSF group (48% v 21% in the placebo group; P = .003). This effect was highly significant in the cohort of patients aged 55 to 64, but only marginal in patients >/=65 years of age. There was a trend toward a longer overall survival (OS) in the GM-CSF group (P = .082). In summary, the administration of GM-CSF, concomitantly with chemotherapy and thereafter during induction course in AML, shortened the time to neutrophil recovery, but did not improve the CR rate in patients aged 55 to 75. Nonetheless, DFS and OS were significantly prolonged in patients aged 55 to 64 treated with GM-CSF. These results are promising and further evaluation of myeloid growth factors in AML is warranted.

GM-CSF-based treatments in COVID-19: reconciling opposing therapeutic approaches.

Therapeutics against coronavirus disease 2019 (COVID-19) are urgently needed. Granulocyte–macrophage colony-stimulating factor (GM-CSF), a myelopoietic growth factor and pro-inflammatory cytokine, plays a critical role in alveolar macrophage homeostasis, lung inflammation and immunological disease. Both administration and inhibition of GM-CSF are currently being therapeutically tested in COVID-19 clinical trials. This Perspective discusses the pleiotropic biology of GM-CSF and the scientific merits behind these contrasting approaches.

Lower respiratory tract delivery, airway clearance, and preclinical efficacy of inhaled GM-CSF in a postinfluenza pneumococcal pneumonia model

Inhaled granulocyte/macrophage colony-stimulating factor (GM-CSF) shows promise as a therapeutic to treat viral and bacterial pneumonia, but no mouse model of inhaled GM-CSF has been described. We sought to 1) develop a mouse model of aerosolized recombinant mouse GM-CSF administration and 2) investigate the protection conferred by inhaled GM-CSF during influenza A virus (IAV) infection against secondary bacterial infection with pneumococcus. To assess lower respiratory tract delivery of aerosolized therapeutics, mice were exposed to aerosolized fluorescein (FITC)-labeled dextran noninvasively via an aerosolization tower or invasively using a rodent ventilator. The efficiency of delivery to the lower respiratory tracts of mice was 0.01% noninvasively compared with 0.3% invasively. The airway pharmacokinetics of inhaled GM-CSF fit a two-compartment model with a terminal phase half-life of 1.3 h. To test if lower respiratory tract levels were sufficient for biological effect, mice were infected intranasally with IAV, treated with aerosolized recombinant mouse GM-CSF, and then secondarily infected with Streptococcus pneumoniae. Inhaled GM-CSF conferred a significant survival benefit to mice against secondary challenge with S. pneumoniae (P < 0.05). Inhaled GM-CSF did not reduce airway or lung parenchymal bacterial growth but significantly reduced the incidence of S. pneumoniae bacteremia (P < 0.01). However, GM-CSF overexpression during influenza virus infection did not affect lung epithelial permeability to FITC-dextran ingress into the bloodstream. Therefore, the mechanism of protection conferred by inhaled GM-CSF appears to be locally mediated improved lung antibacterial resistance to systemic bacteremia during IAV infection.

Combined GM-CSF and G-CSF administration mobilizes CD4+ CD25hi Foxp3hi Treg in leukapheresis products of rhesus monkeys.

Early phase clinical trials are evaluating the feasibility, safety, and therapeutic potential of ex vivo expanded regulatory T cells (Treg) in transplantation. A limitation is the paucity of naturally occurring Treg numbers in peripheral blood. Hence, protracted ex vivo expansion is required to obtain sufficient Treg in order to meet target cell doses. Because cytokine administration has been used successfully to mobilize immune cells to the peripheral blood in experimental and clinical studies, we hypothesized that granulocyte macrophage-colony-stimulating factor (GM-CSF) and granulocyte-CSF (G-CSF) administration would enhance Treg percentages in leukapheresis products of rhesus monkeys. Following combined GM-CSF and G-CSF administration, the incidence of Treg in peripheral blood and leukapheresis products was elevated significantly, where approximately 3.7×106 /kg CD4+ CD25hi Foxp3hi or 6.8×106 /kg CD4+ CD25hi CD127lo Treg can be collected from individual products. Mobilized Treg expressed a comparable repertoire of surface markers, chemokine receptors, and transcription factors to naïve monkey peripheral blood Treg. Furthermore, when expanded ex vivo, mobilized leukapheresis product and peripheral blood Treg exhibited similar ability to suppress autologous CD4+ and CD8+ T cell proliferation. These observations indicate that leukapheresis products from combined GM-CSF- and G-CSF-mobilized individuals are a comparatively rich source of Treg and may circumvent long-term ex vivo expansion required for therapeutic application.

Determinants of combination GM-CSF immunotherapy and oncolytic virotherapy success identified through in silico treatment personalization.

Oncolytic virotherapies, including the modified herpes simplex virus talimogene laherparepvec (T-VEC), have shown great promise as potent instigators of anti-tumour immune effects. The OPTiM trial, in particular, demonstrated the superior anti-cancer effects of T-VEC as compared to systemic immunotherapy treatment using exogenous administration of granulocyte-macrophage colony-stimulating factor (GM-CSF). Theoretically, a combined approach leveraging exogenous cytokine immunotherapy and oncolytic virotherapy would elicit an even greater immune response and improve patient outcomes. However, regimen scheduling of combination immunostimulation and T-VEC therapy has yet to be established. Here, we calibrate a computational biology model of sensitive and resistant tumour cells and immune interactions for implementation into an in silico clinical trial to test and individualize combination immuno- and virotherapy. By personalizing and optimizing combination oncolytic virotherapy and immunostimulatory therapy, we show improved simulated patient outcomes for individuals with late-stage melanoma. More crucially, through evaluation of individualized regimens, we identified determinants of combination GM-CSF and T-VEC therapy that can be translated into clinically-actionable dosing strategies without further personalization. Our results serve as a proof-of-concept for interdisciplinary approaches to determining combination therapy, and suggest promising avenues of investigation towards tailored combination immunotherapy/oncolytic virotherapy.

A Phase II Trial Evaluating the Efficacy and Safety of Sargramostim Post Infusion of T -Replete HLA Mismatched Peripheral Blood Haploidentical Hematopoietic Stem Cells with Post Transplant Cyclophosphamide

Phase II trial evaluating the Efficacy and Safety of Sargramostim Post Infusion of T -Replete HLA Mismatched Peripheral Blood Haploidentical Hematopoietic Stem Cells with Post-Transplant Cyclophosphamide Background: T-replete HLA mismatched haploidentical transplantation (Haplo) with post-transplant cyclophosphamide (PTCY) is widely used for patients lacking a suitably matched donor. Patients who receive haplo with PTCY usually start growth factor support (G-CSF) on day +5 for neutropenia prophylaxis. G-CSF is a specific stimulator of the growth and differentiation of hematopoietic progenitor cells committed to the neutrophil lineage. Granulocyte-macrophage colony-stimulating factor (GM-CSF) on the other hand, is not restricted to neutrophils because it also affects monocytes and eosinophils and plays a central role in antifungal host response. In a prior randomized study among 206 matched allogeneic HCT patients (wang et al, J Clin Oncol. 2015;33(34):3999-4006), neutropenia prophylaxis with GM-CSF +/- G-CSF had significantly lower 100-day TRM, lower 100-day cumulative mortality, lower infection related mortality and lower 600-day invasive fungal disease related mortality compared to G-CSF. Given the increase number of HLA mismatched haplos with PTCY performed each year and the high risk of infectious complications associated with this type of transplant, we suggest that GM-CSF administration post haplo and PTCY can yield similar count recovery rate to GCSF with a potential of lowering risk of infectious complications. Endpoints : The primary endpoint is to establish equivalent effectiveness of sargramostim to a matched control cohort of G-CSF treated patients in time to neutrophil engraftment (ANC&gt;500 x 3 days) post haplo with PTCY. Secondary endpoints: estimates of OS, DFS, relapse rate, GVHD and TRM. Donor chimerism at days 30, 60, 100 and 6 months post-transplant. Incidence and grade of cytokine release syndrome between day 0 and 30. Incidence of infectious complications and infection related mortality at day 100. Immune profiling assay "CYTOF" will be measured at days 30, 60, 90 and 180 for functional and phenotypic immune analysis. Other secondary endpoints include length of hospital stay and charges-based cost comparison during the first 100 days between sargramostim and G-CSF matched controls. All primary and secondary endpoints will be reported for the study group and compared to a matched control cohort from our database containing patients who received haplo with PTCY using G-CSF for neutropenia prophylaxis. A set of 20 patients, who are not on the Sargramostim study and receiving haplo transplant with G-CSF at the same time of the study accrual period, will be consented for immunoprofiling assay at days 30, 60, 100 and 180. Methods: Patients aged 18-78 years with an available 5/10-8/10 HLA- matched related donor with high risk hematological malignancy with adequate organ function will be enrolled for the study. Patients will receive Sargramostim 250mg/m2 /day subcutaneous starting day +5 post haplo/PTCY and continue till ANC&gt;1000x 3 days or &gt;1500x 1 day. If grade 3 or 4 adverse reactions occur, reduce dose by 50% or temporarily discontinue the dose until the reaction abates. Conditioning regimens to be used include previously published and currently used at our center (Flu/Cy/TBI, Flu/high dose TBI or Flu/Mel). Treatment will be in the outpatient setting and admissions if clinically indicated. Sample Size Determination : Time to ANC&gt;500 will be evaluated between the prospectively enrolled patients and matched historical controls. Based on the data of haplo transplants done at Northside in 2010-2016, the standard deviations (SD) was 3 days for time to ANC500. The correlation in measurements between prospective patient and matched control is conservatively assumed to be 0.1. SD for differences between matched pairs would be 3.55 days for time to ANC500. To control the type I error to be 5%, the 90% paired t confidence interval for difference in time to ANC500 should be constructed and its upper boundary will be compared to the non-inferiority margin 2 days. The size of 35 prospective patients provides the power 90% for concluding that time to ANC500 for Sargramostim is no more than 2 days longer than historical controls. The actual enrollment size is decided to be 38 to accommodate 10% of drop off rate. Enrollment: The study is expect to start enrolling patients October 2019. Disclosures No relevant conflicts of interest to declare.

GM-CSF Enhances Mobilization of Bone Marrow Mesenchymal Stem Cells via a CXCR4-Medicated Mechanism.

This study was conducted to investigate the effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) on the mobilization of mesenchymal stem cells (MSCs) from the bone marrow (BM) into the peripheral blood (PB) in rats. GM-CSF was administered subcutaneously to rats at 50μg/kg body weight for 5 consecutive days. The BM and PB of rats were collected at 1, 3, and 5days during the administration for analysis. Upon GM-CSF administration, the number of mononuclear cells increased rapidly at day 1 both in the BM and PB. This number decreased gradually over time in the BM to below the initial amount by day 5, but was maintained at a high level in the PB until day 5. The colony-forming unit-fibroblasts were increased in the PB by 10.3-fold at day 5 of GM-CSF administration, but decreased in the BM. Compared to GM-CSF, granulocyte-colony stimulating factor (G-CSF) stimulated lower levels of MSC mobilization from the BM to the PB. Immunohistochemical analysis revealed that GM-CSF induced a hypoxic and proteolytic microenvironment and increased C-X-C chemokine receptor type 4 (CXCR4) expression in the BM. GM-CSF added to BM MSCs in vitro dose-dependently increased CXCR4 expression and cell migration. G-CSF and stromal cell derived factor-1 (SDF-1) showed similar results in these in vitro assays. Know-down of CXCR4 expression with siRNA significantly abolished GM-CSF- and G-CSF-induced MSC migration in vitro, indicating the involvement of the SDF-1-CXCR4 interaction in the mechanism. These results suggest that GM-CSF is a useful tool for mobilizing BM MSCs into the PB.

RNA-Modified T Cells Mediate Effective Delivery of Immunomodulatory Cytokines to Brain Tumors.

With the presence of the blood-brain barrier (BBB), successful immunotherapeutic drug delivery to CNS malignancies remains a challenge. Immunomodulatory agents, such as cytokines, can reprogram the intratumoral microenvironment; however, systemic cytokine delivery has limited access to the CNS. To bypass the limitations of systemically administered cytokines, we investigated if RNA-modified Tcells could deliver macromolecules directly to brain tumors. The abilities of Tcells to cross the BBB and mediate direct cytotoxic killing of intracranial tumors make them an attractive tool as biological carriers. Using Tcell mRNA electroporation, we demonstrated that activated Tcells can be modified to secrete granulocyte macrophage colony-stimulating factor (GM-CSF) protein while retaining their inherent effector functions invitro. GM-CSF RNA-modified Tcells effectively delivered GM-CSF to intracranial tumors invivo and significantly extended overall survival in an orthotopic treatment model. Importantly, GM-CSF RNA-modified Tcells demonstrated superior anti-tumor efficacy as compared to unmodified Tcells alone or in combination with systemic administration of recombinant GM-CSF. Anti-tumor effects were associated with increased IFN-γ secretion locally within the tumor microenvironment and systemic antigen-specific Tcell expansion. These findings demonstrate that RNA-modified Tcells may serve as a versatile platform for the effective delivery of biological agents to CNS tumors.

GM-CSF improves the immune response to the diphtheria-component in a multivalent vaccine

Multivalent tetanus and diphtheria toxoid containing vaccines belong to the most frequently applied vaccines. However, there is an imbalance in the degree of protection against the two antigens with insufficient long-term protection against diphtheria, particularly in the elderly population. We have previously reported a positive correlation between granulocyte macrophage-colony stimulating factor (GM-CSF) and the production of diphtheria-specific antibodies. Therefore, in the present study we analyzed the effects of in vivo applied recombinant GM-CSF on immunization with multivalent tetanus/diphtheria vaccine in mice of different age. In vivo application of GM-CSF lead to enhanced production of diphtheria-specific antibodies as well as more diphtheria-specific CD4+ T cells following vaccination with multivalent tetanus/diphtheria vaccine. In contrast, the humoral and cellular immune response to the tetanus component was unaltered. Furthermore, application of GM-CSF resulted in more splenic CD11b+ dendritic cells (DCs) with a higher MHC-II expression. GM-CSF also induced a stronger recruitment of CD11b+ DCs to the injected muscle. Most remarkably, GM-CSF was able to boost the diphtheria-specific immune response to the multivalent vaccine in aged mice. This study demonstrates that local administration of GM-CSF is able to improve immune responsiveness to the diphtheria component of multivalent tetanus/diphtheria vaccine in young and old mice. This information could be useful for the future design of vaccines for the elderly.

Biological Effects of Anti-Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) Antibody Formation in Patients Treated With GM-CSF (Sargramostim) as Adjuvant Therapy of Melanoma.

We investigated the development of binding and neutralizing antibodies to granulocyte-macrophage colony-stimulating factor (GM-CSF) in patients receiving prolonged therapy with GM-CSF as adjuvant therapy of melanoma and the impact of these antibodies on biological effects. Fifty-three patients with high-risk melanoma that had been surgically excised were treated with GM-CSF, 125 μg/m daily for 14 days every 28 days for 1 year after surgical resection of disease. Serum samples for antibodies to GM-CSF were measured before treatment and on study days 155 and 351. Blood draws for testing biological effects were keyed to GM-CSF administration: days 0 (before), 15 (after 14 d on GM-CSF), 29 (after 14 d off GM-CSF), 155, and 351 (after 14 d on GM-CSF in the sixth and 13th cycle of treatment). Of 53 patients enrolled, 43 were evaluable for the development of anti-GM-CSF antibodies. Of these, 93% developed binding antibodies and 42% developed both binding and neutralizing antibodies. The increase in the white blood cell count, percent eosinophils, or neopterin levels engendered by GM-CSF administration was abrogated or markedly decreased in patients with neutralizing antibodies but not in patients who developed only binding antibodies. Ninety-three percent of patients with melanoma treated with GM-CSF as adjuvant therapy develop antibodies to GM-CSF. In those with neutralizing antibodies, a diminution of the biological effects of GM-CSF was observed. The development of neutralizing antibodies might also abrogate the potential clinical benefit of this treatment and should be considered in the design of future clinical trials.

Granulocyte macrophage – colony stimulating factor (GM-CSF) significantly enhances articular cartilage repair potential by microfracture

To investigate whether granulocyte macrophage-colony stimulating factor (GM-CSF) can be used to increase the number of mesenchymal stem cells (MSCs) in blood clots formed by microfracture arthroplasty (MFX) and whether it can improve the therapeutic outcome for cartilage repair. Thirty-six New Zealand white rabbits were divided into four groups: (1) control, (2) GM-CSF, (3) MFX, and (4) GM-CSF+MFX. GM-CSF was administrated intravenously (IV) at 10μg/kg body weight 20min before the MFX surgery. The repaired tissues were retrieved and examined by histological observation, quantitative assessment, and biochemical assays at 4, 8, and 12 weeks after treatment. The number of MSCs was measured in the blood clots by the colony forming unit-fibroblast (CFU-F) assay. The kinetic profile and distribution of GM-CSF invivo was also evaluated by near-Infrared (NIR) fluorescence imaging and enzyme-linked immune sorbent assay. In the histological observations and chemical assays examined at 4, 8, and 12 weeks, the MFX after GM-CSF administration showed better cartilage repair than the one without GM-CSF. The CFU-F assay showed a significantly larger amount of MSCs present in the blood clots of the GM-CSF+MFX group than in the blood clots of the other groups. The blood concentration of GM-CSF peaked at 10min and decreased back to almost the initial level after a couple of hours. GM-CSF was distributed in many organs including the bone marrow but was not observed clearly in the joint cavity. Intravenous administration of GM-CSF together with MFX could be a promising therapeutic protocol to enhance the repair of cartilage defects.

The Effects of Ex Vivo Administration of Granulocyte-Macrophage Colony-Stimulating Factor and Endotoxin on Cytokine Release of Whole Blood Are Determined by Priming Conditions.

Background Lipopolysaccharide- (LPS-) induced tumour necrosis factor alpha (TNFα) secretion in critically ill patients can be considered as a measure of immune responsiveness. It can be enhanced by granulocyte-macrophage colony stimulating factor (GM-CSF). We investigated the effect of GM-CSF on ex vivo stimulated cytokine production using various preincubation regimens in healthy donors and patients with sepsis. Results The maxima for the stimuli occurred 3 hours after stimulation. In donors, there was an increase (p < 0.001) of LPS-induced TNFα levels following incubation with GM-CSF. The simultaneous incubation with GM-CSF and LPS caused an inhibition of TNFα production (p < 0.001). Postincubation with GM-CSF did not yield any difference. In patients, preincubation with GM-CSF yielded an enhanced ex vivo TNFα-response when TNFα levels were low. Patients with increased TNFα concentrations did not show a GM-CSF stimulation effect. The GM-CSF preincubation yielded an increase of IL-8 production in patients and donors. Conclusions This study demonstrates the immune-modulating properties of GM-CSF depending on the absence or presence of LPS or systemic TNFα. The timing of GM-CSF administration may be relevant for the modulation of the immune system in sepsis. The lack of stimulation in patients with high TNFα may represent endotoxin tolerance.

Invited commentary

Dr Edwards and colleagues have detailed the in vivo angiogenic potential of an engineered stromal cell-derived factor-1α (SDF) in a rat arterial ligation model. SDF is a powerful chemoattractant of endothelial progenitor cells (EPCs), which represent a cornerstone of the response to ischemia and angiogenesis. Several studies have highlighted the therapeutic role of SDF to increase migration of EPCs and activation of EPCs, to improve healing of diabetic wounds, and to improve angiogenesis and ventricular physiology in cardiac models. A major hurdle to translation of SDF clinically has been the susceptibility to protease degradation and a complex tertiary structure that limits cost-effective production. Gene delivery approaches to overcome these issues add orders of magnitude to the complexity of potential SDF therapies in terms of vector toxicity and regulation of gene expression. The distinctive aspect of this study by Edwards et al is the use of an engineered SDF analog (ESA) peptide that mimics the physiologic properties of recombinant SDF but at a fraction of the size. The authors found that administration of ESA resulted in increased vascular endothelial growth factor expression, capillary density, and limb perfusion over a clinically relevant interval of 14 days. A significant limitation of this study was the administration of the cytokine granulocyte-macrophage colony-stimulating factor (GMCSF) to upregulate bone marrow EPCs in all study groups. Although GMCSF alone has not been shown to improve perfusion without a chemotactic agent such as SDF, the prospective administration of GMCSF clinically represents a significant additional therapeutic for eventual clinical translation. If future studies can demonstrate that ESA mediates angiogenesis independent of GMCSF, this would significantly improve the appeal of engineered SDF. Also, as noted by the authors, they used a model of acute rather than the intended clinical application of chronic ischemia. Potentially, mechanisms of EPC recruitment and the effect of SDF therapies might differ between these two scenarios. Although angiogenic therapies are unlikely to replace current macrovascular open and endovascular surgical approaches, they will be especially useful in scenarios where distal outflow has been compromised by conditions such as diabetes or chronic distal embolism, for instance. Broadly, these therapies should improve distal tissue perfusion and offer additional applications in coronary ischemia. The findings of this study are compelling and represent a meaningful step toward the frontier of angiogenic therapy in peripheral vascular disease. Biochemically engineered stromal cell-derived factor 1-alpha analog increases perfusion in the ischemic hind limbJournal of Vascular SurgeryVol. 64Issue 4PreviewDespite promising therapeutic innovation over the last decade, peripheral arterial disease remains a prevalent morbidity, as many patients are still challenged with peripheral ischemia. We hypothesized that delivery of engineered stromal cell-derived factor 1-alpha (ESA) in an ischemic hind limb will yield significant improvement in perfusion. Full-Text PDF Open Archive

Cytokine amplification and macrophage effector functions in aortic inflammation and abdominal aortic aneurysm formation

On April 29, 2015, Son and colleagues published an article entitled "Granulocyte macrophage colony-stimulating factor (GM-CSF) is required for aortic dissection/intramural haematoma" in Nature Communications. The authors observed that the heterozygous Kruppel-like transcription factor 6 (KLF6) deficiency or absence of myeloid-specific KLF6 led to upregulation of macrophage GM-CSF expression, promoted the development of aortic hematoma/dissection, and stimulated abdominal aortic aneurysm (AAA) formation when the vessel wall was subjected to an inflammatory stimulus. The additional findings of increased adventitial fibrotic deposition, marked infiltration of macrophages, and increased expression of matrix metalloprotease-9 (MMP-9) and IL-6 were blocked with neutralizing GM-CSF antibodies, or recapitulated in normal mice with excess GM-CSF administration. The authors concluded that GM-CSF is a key regulatory molecule in the development of AAA and further suggested that activation of GM-CSF is independent of the transforming growth factor β (TGFβ)-Smad pathway associated with the Marfan aortic pathology. In this perspective, we expand on this mechanism, drawing from previous studies implicating a similar essential role for IL-6 signaling in macrophage activation, Th17 expansion and aortic dissections. We propose a sequential "two-hit" model of vascular inflammation involving initial vascular injury followed by recruitment of Ly6C(hi) macrophages. Aided by fibroblast interactions inflammatory macrophages produce amplification of IL-6 and GM-CSF expression that converge on a common, pathogenic Janus kinase (JAK)-signal transducers and activations of transcription 3 (STAT3) signaling pathway. This pathway stimulates effector functions of macrophages, promotes differentiation of Th17 lymphocytes and enhances matrix metalloproteinase expression, ultimately resulting in deterioration of vascular wall structural integrity. Further research evaluating the impact of interventions modulating this common JAK-STAT3 pathway may yield new therapeutic interventions for late stages of vascular expansion in inflammation driven aortic disease.

GM-CSF Enhances Macrophage Glycolytic Activity In Vitro and Improves Detection of Inflammation In Vivo.

(18)F-FDG accumulates in glycolytically active tissues and is known to concentrate in tissues that are rich in activated macrophages. In this study, we tested the hypotheses that human granulocyte-macrophage colony-stimulating factor (GM-CSF), a clinically used cytokine, increases macrophage glycolysis and deoxyglucose uptake in vitro and acutely enhances (18)F-FDG uptake within inflamed tissues such as atherosclerotic plaques in vivo. In vitro experiments were conducted on human macrophages whereby inflammatory activation and uptake of radiolabeled 2-deoxyglucose was assessed before and after GM-CSF exposure. In vivo studies were performed on mice and New Zealand White rabbits to assess the effect of GM-CSF on (18)F-FDG uptake in normal versus inflamed arteries, using PET. Incubation of human macrophages with GM-CSF resulted in increased glycolysis and increased 2-deoxyglucose uptake (P < 0.05). This effect was attenuated by neutralizing antibodies against tumor necrosis factor-α or after silencing or inhibition of 6-phosphofructo-2-kinase. In vivo, in mice and in rabbits, intravenous GM-CSF administration resulted in a 70% and 73% increase (P < 0.01 for both), respectively, in arterial (18)F-FDG uptake in atherosclerotic animals but not in nonatherosclerotic controls. Histopathologic analysis demonstrated a significant correlation between in vivo (18)F-FDG uptake and macrophage staining (R = 0.75, P < 0.01). GM-CSF substantially augments glycolytic flux in vitro (via a mechanism dependent on ubiquitous type 6-phosphofructo-2-kinase and tumor necrosis factor-α) and increases (18)F-FDG uptake within inflamed atheroma in vivo. These findings demonstrate that GM-CSF can be used to enhance detection of inflammation. Further studies should explore the role of GM-CSF stimulation to enhance the detection of inflammatory foci in other disease states.

Role of Granulocyte-Macrophage Colony-Stimulating Factor Signaling in Regulating Neutrophil Antifungal Activity and the Oxidative Burst During Respiratory Fungal Challenge.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a pleiotropic cytokine that plays a critical role in regulating myeloid cell host defense. In this study, we demonstrated that GM-CSF signaling plays an essential role in antifungal defense against Aspergillus fumigatus. Mice that lack the GM-CSF receptor β chain (GM-CSFRβ) developed invasive hyphal growth and exhibited impaired survival after pulmonary challenge with A. fumigatus conidia. GM-CSFRβ signaling regulated the recruitment of inflammatory monocytes to infected lungs, but not the recruitment of effector neutrophils. Cell-intrinsic GM-CSFRβ signaling mediated neutrophil and inflammatory monocyte antifungal activity, because lung GM-CSFRβ(-/-) leukocytes exhibited impaired conidial killing compared with GM-CSFRβ(+/+) counterparts in mixed bone marrow chimeric mice. GM-CSFRβ(-/-) neutrophils exhibited reduced (hydrogenated) nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity in vivo. Conversely, administration of recombinant GM-CSF enhanced neutrophil NADPH oxidase function, conidiacidal activity, and lung fungal clearance in A. fumigatus-challenged mice. Thus, our study illustrates the functional role of GM-CSFRβ signaling on lung myeloid cell responses against inhaled A. fumigatus conidia and demonstrates a benefit for systemic GM-CSF administration.