Mobilization Of Progenitor Cells Research Articles

Tibial transverse transport induces mobilization of endothelial progenitor cells to accelerate angiogenesis and ulcer wound healing through the VEGFA/CXCL12 pathway

BackgroundTibial transverse transport (TTT) can promote the healing of chronic foot ulcers, but the specific cellular and molecular mechanisms by which TTT promotes wound healing remain unclear. MethodsNew Zealand White rabbits were selected to induce foot ulcers by implanting a magnetic sheet for circulation compression. The treatment included unilateral TTT surgery and bilateral TTT surgery. Observation of tissue neovascularization structure by HE staining and CD31 immunofluorescence detection. Collagen fiber formation was detected through Masson staining. The mobilization of endothelial progenitor cell (EPCs) were analyzed by VEGFR2 immunofluorescence detection and flow cytometry detection of the number of VEGFR2/Tie-2-positive cells in peripheral blood. ELISA and qPCR assay were performed to detect VEGFA and CXCL12 levels. ResultsThe complete healing time of ulcer surfaces in sham, unilateral and bilateral TTT groups was about 22 days, 17 days and 13 days, respectively. TTT treatment significantly increased the deposition of granulation tissue and epithelialization of wounds. It also led to an increase in collagen fiber content and the level of the microvascular marker CD31. Furthermore, TTT treatment upregulated the levels of VEGFA and CXCL12 in peripheral blood and wound tissues, as well as increased the expression of VEGFR2 in wound tissues and the proportion of VEGFR2/Tie-2 in peripheral blood. Moreover, these effects of TTT treatment in the bilateral group was more significant than that in the unilateral group. ConclusionsTTT may facilitate wound fibroblasts to release VEGFA and CXCL12, causing EPC mobilization, thus promoting angiogenesis and ulcer wound healing.

Survivors of polymicrobial sepsis are refractory to G-CSF-induced emergency myelopoiesis and hematopoietic stem and progenitor cell mobilization

Sepsis survivors exhibit immune dysfunction, hematological changes, and increased risk of infection. The long-term impacts of sepsis on hematopoiesis were analyzed using a surgical model of murine sepsis, resulting in 50% survival. During acute disease, phenotypic hematopoietic stem and progenitor cells (HSPCs) were reduced in the bone marrow (BM), concomitant with increased myeloid colony-forming units and extramedullary hematopoiesis. Upon recovery, BM HSPCs were increased and exhibited normal function in the context of transplantation. To evaluate hematopoietic responses in sepsis survivors, we treated recovered sham and cecal ligation and puncture mice with a mobilizing regimen of granulocyte colony-stimulating factor (G-CSF) at day 20 post-surgery. Sepsis survivors failed to undergo emergency myelopoiesis and HSPC mobilization in response to G-CSF administration. G-CSF is produced in response to acute infection and injury to expedite the production of innate immune cells; therefore, our findings contribute to a new understanding of how sepsis predisposes to subsequent infection.

The Role of Angiogenesis Mediators in the Mobilization of Early and Late Endothelial Progenitor Cells from the Bone Marrow in Coronary Heart Disease

Background. A severe form of coronary heart disease (CHD) is ischemic cardiomyopathy (ICMP), the pathogenesis of which has not been fully studied. Disturbances in the mobilization of endothelial progenitor cells (EPC) due to an imbalance of angiogenesis mediators may exacerbate ischemia in ICMP. The aim — to establish the peculiarities of changes in the balance of early and late EPС and subpopulations of VEGFR2+ cells in the blood and bone marrow in relation to the content of angiogenesis mediators and the number of desquamated endothelial cells (DEK) in the blood of patients with CHD, suffering and not suffering from ICMP. Methods. A single-stage, clinical, controlled (case-control) study was conducted from March 2019 to June 2022. 52 patients with CHD who had a history of myocardial infarction were examined: 30 people suffering from ICMP and 22 people not suffering from ICMP, as well as 15 healthy donors. The content of VEGFR2+, VEGFR2+CD34+CD14+ (early EPC), VEGFR2+CD34+CD14– (late EPC), VEGFR2+CD34–CD14+, VEGFR2+CD34–CD14– cells in patients with CHD in the blood (before surgery) and bone marrow (sampling was performed at the beginning of coronary bypass) and in healthy individuals in the blood, as well as (in both groups) the content of CD45–CD146+ DEC in the blood was determined by flow cytometry. The concentration of SDF-1, VEGF-A, MCP-1, GM-CSF, G-CSF in blood plasma was measured by multiplex immunofluorescence analysis. Results. The development of CHD without cardiomyopathy was accompanied by an increase in the content of VEGFR2+CD34+CD14+ and VEGFR2+ cells (0.74 [0.46; 1.23]% and 10.00 [8.20; 11.60]%, respectively, versus 0.19 [0.13; 0.32]%, p 0.001 and 5.40 [4.30; 6.50]%, p = 0.005) and concentrations of SDF-1, MCP-1, GM-CSF (respectively 60.00 [50.00; 81.00] pg/ml; 223.0 [180.0; 297.0] pg/ml; 2.10 [1.45; 3.40] pg/ml versus 30.00 [5.00; 45.00] pg/ml, p = 0.041; 175.1 [140.0; 204.0] pg/ml, p = 0.046; 0.96 [0.46; 1.41] pg/ml, p = 0.038) in the blood relative to the norm. No such changes were observed in patients with ICMP. Regardless of the presence of ICMP, the content of VEGFR2+CD34+CD14–, VEGFR2+CD34–CD14+, VEGFR2+CD34–CD14– cells, VEGF-A, G-CSF in the blood of patients with CHD varied within physiological values, and the number of DEC exceeded the norm (7.26 [5.43; 17.94]×105/l, p = 0.039). The number of VEGFR2+ cells and their immunophenotypes in the bone marrow of patients with ICMP did not differ from the parameters in patients with CHD without cardiomyopathy. Prolonged bleeding from the venopuncture area was registered in one CHD patient without cardiomyopathy. Conclusion. The development of ICMP is associated with the absence of a compensatory response to atherogenesis in the form of increased mobilization of early EPC from the bone marrow due to the absence of a reaction associated with hyperproduction of SDF-1, MCP-1, GM-CSF, which is characteristic of CHD without cardiomyopathy. The content of EPС, VEGFR2+CD34–CD14+ and VEGFR2+CD34–CD14– cells, VEGF-A and G-CSF in the blood in СHD corresponds to physiological values, regardless of the presence of ICMP. The generation of EPC in the bone marrow in ICMP is not impaired.

Effect of voxelotor on murine bone marrow and peripheral blood with hematopoietic progenitor cell mobilization for gene therapy of sickle cell disease

In preparation for hematopoietic stem cell mobilization and collection, current ex vivo gene therapy protocols for sickle cell disease require patients to undergo several months of chronic red cell transfusion. For health care equity, alternatives to red cell transfusion should be available. We examined whether treatment with GBT1118, the murine analog of voxelotor, could be a safe and feasible alternative to red cell transfusion. We found that 3 weeks of treatment with GBT1118 increased the percentage of bone marrow hematopoietic stem cells and upon plerixafor mobilization, the percentage of peripheral blood hematopoietic stem cells. Our data suggest that voxelotor should be further explored for its potential safety and utility as preparation for hematopoietic stem cell mobilization and collection.

Novel Small Molecule VLA-4 Inhibitors Optimized for Extended Hematopoietic and Progenitor Cell Mobilization

Background: Hematopoietic stem and progenitor cell (HSPC) transplant is an essential treatment for a variety of blood disorders and malignancies, and more recently, for gene editing therapies such as sickle cell anemia. A key step in this procedure is the effective mobilization of a large quantity of primitive donor HSPCs to ensure a durable and long lasting engraftment capable of developing into all blood cell lineages. The most commonly used regimen for donor mobilization is a 5-day course of Granulocyte Colony Stimulating Factor (G-CSF). However, G-CSF does not effectively mobilize a sufficient number or quality of stem cells in all donors, can have unwanted side effects, and is contraindicated in sickle cell disease. Therefore, it is desirable to identify an alternative treatment that is safe, rapid and cost effective. The cell surface integrin receptor VLA-4 (a4b1) and the chemokine receptor CXCR4 are essential for HSPC homing and retention in the bone marrow. Inhibition of these receptors rapidly mobilizes HSPCs within an hour, as opposed to the multi-day process using G-CSF. Small molecule inhibitors of VLA-4 have been reported previously, but most have poor pharmacokinetic properties and/or weak inhibition of VLA4. These inhibitors rapidly mobilize HSPCs into the peripheral blood of mice after a single s.c. injection, but their effect is short lived, yielding an inadequate number of HSPCs necessary for stem cell transplantation or for gene therapy. Therefore, VLA4 inhibitors with improved pharmacokinetic properties imparting extended and greater HSPC mobilization after a single dose is desirable. Methods: We designed and synthesized multiple novel VLA-4 inhibitor molecules and tested their potency using soluble VCAM-1 binding assays. Inhibitors determined to be most potent with improved aqueous solubility were then tested in vivo in DBA mice for extended HSPC mobilization beyond 4 hours after a single SC injection, alone and in combination with the CXCR4 inhibitors. Results: We developed two main core molecules that each incorporate key VLA4 receptor binding motifs critical for potent inhibition of VLA4 binding to VCAM-1. Our first generation of inhibitors were quite potent and rapidly mobilized HSPCs, but their effect was short lived and yielded insufficient numbers of HSPCs for gene editing and engraftment studies. Most had poor solubility and very short plasma half-lives after s.c. injection in mice. We designed later generation analogues that strategically exploited a region of each optimized core, allowing for covalent addition of polyethylene glycol (PEG) chains of increasing length without decreasing potency. We determined that a minimum PEG length of 24 PEG units was required for extended HSPC mobilization in mice. WU-106, one of our VLA-4 inhibitors containing 24 PEG units, exhibited excellent aqueous solubility, longer plasma half-life after s.c. dosing, and mobilized 2-fold more murine HSPCs for a longer time than previously published best-in-class VLA-4 inhibitors or our first generation VLA4 inhibitor leads. Importantly, a synergistic effect on HSPC mobilization was achieved when WU-106 was co-administered with CXCR4 inhibitors (Plerixafor or BL-8040). Further optimization by the addition of longer PEG chains, even up to 40KD, retained sub nM potency and extended mobilization beyond 24 hours after a single injection. Our 20kD PEG analogues attached to our two different core molecules (WU-125 and WU-133) allowed for dosing of the drug in the evening, with maximum mobilization still present the next morning, thereby enabling HSPC collection to initiate soon (2-4 hours) after CXCR4 inhibitor dosing in the morning. The quantity of HSPCs obtained using this staggered dosing regimen was greater than simultaneous administration of the VLA-4 and CXCR4 inhibitors ( Fig. 1). Furthermore, our novel, long-acting PEG analogues demonstrated superior HSPC mobilization compared to an alpha 4-targeted antibody (anti-CD49d) in mice ( Fig.2). Conclusion: We have developed novel, potent PEGylated small molecule VLA-4 inhibitors that have excellent aqueous solubility and pharmacokinetics. The kinetics and magnitude of HSPC mobilization by our PEGylated inhibitors are superior to other previously described VLA-4 inhibitors and an antibody to alpha-4(anti-CD49d).

Resource Utilization Analysis of Two Algorithms for Hematopoietic Progenitor Cell Mobilization in Multiple Myeloma

Background: Autologous hematopoietic cell transplantation (HCT) is a standard of care after induction therapy for multiple myeloma (MM). A key step in this procedure is the mobilization and collection of hematopoietic progenitor cells (HPC). HPC mobilization typically uses G-CSF with or without the CXCR4 antagonist Plerixafor (P). Although P increases the effectiveness of mobilization and may reduce the number of apheresis sessions, it is associated with significantly increased cost per dose. There is significant heterogeneity to HPC collection algorithms across institutions and there is no clear standard. At the Cleveland Clinic, our HPC collection algorithm was updated in an effort to reduce the use and associated cost of P. The criteria for initiating P became more stringent and far fewer patients were initiated on P prior to their first session of HPC collection apheresis. Prior to October 2017, patients were initiated on P if any 1 of the following criteria were met: age>60 years, prior treatment with melphalan or other alkylating therapy, prior treatment with lenalidomide >2 cycles, extensive bone marrow disease, or platelet count <100K. Starting October 1, 2017, patients were preemptively initiated on P prior to first collection only if all 3 of the following criteria were met: age > 65 years, lenalidomide > 6 cycles, and platelet count < 100K. However, P was added after the first apheresis session if peripheral blood CD34+ cell count was <20/uL or HPC yield was unsatisfactory (<2 x 10^6 CD34+ cells). Furthermore, target CD34 yield was decreased from 5 to 4 x 10^6 CD34+ cells. Herein, we perform a comparative resource utilization analysis of HPC collection at our center. Methods: We retrospectively collected HPC mobilization data on patients undergoing HCT for MM from 1/12014 to 12/31/2020. We determined the number of P doses, number of apheresis sessions, and HPC collection totals per patient. Patient characteristics were summarized in median, interquartile range (IQR), or frequencies and percentages as appropriate. Fisher's exact test and Wilcoxon rank sum test were used to compare variables in patients undergoing mobilization prior to versus after 10/1/2017. All tests were two-sided and p-values of 0.05 or less were considered statistically significant. Results: 219 patients underwent HPC mobilization from 1/1/2014 to 9/30/2017 and 251 patients underwent mobilization after algorithm change from 10/1/2017 to 12/31/2020. As anticipated, the protocol change decreased the number of patients receiving P prior to their first apheresis session. 91% received P prior to the first apheresis session before the change while 14% received this initial dose of P after the change. Prior to the change 51% of patients completed collection in 1 day, 30% completed in 2 days, 12 % completed in 3 days, and 7% completed in 4 days or more. These figures changed to 20%, 41%, 23%, and 17% respectively following the change (p<0.0001) Median day 1 peripheral blood CD34 count decreased from 63 to 19 cells/uL while median day 1 CD34 collection yield fell from 4.8 to 1.46 x 10^6 after the change (p<0.0001) (Table 1). Total CD34 collection yield also decreased from a median of 6.64 to 4.6 x 10^6 CD34+ cells (p<0.0001). However, the target yield was decreased from 5 to 4 x 10^6 CD34+ cells as described above. The number of doses of P per patient decreased after the change (pre-change median dose / patient = 1, IQR = 1-2) (post-change median dose / patient = 1, IQR = 0-2) (p=0.004). The average number of apheresis sessions required per patient increased following the change (pre-change median apheresis sessions = 1, IQR = 1-2) (median post change apheresis sessions = 2, IQR = 2-3) (p<0.0001) (Figure 1). Conclusion: Changes to our institutional HPC mobilization algorithm led to a substantial decrease in the use of preemptive P prior to day 1 of collection by design. The resulting decrease in total doses of P per patient was smaller than expected, although still statistically significant. However, this was offset by a concomitant significant increase in the number of apheresis sessions required per patient despite a lower collection target. Based on these results, a cost analysis is ongoing in order to re-evaluate our institutional algorithm.

Combination of Propranolol and a Novel CXCR4 Antagonist Burixafor (GPC-100) for Enhanced Hematopoietic Cell Mobilization

Burixafor (GPC-100), a novel CXCR4 antagonist, has shown safe and effective mobilization of hematopoietic stem and progenitor cells (HSPC) in a phase I clinical study. In multiple myeloma patients, GPC-100 combined with granulocyte-colony stimulating factor (G-CSF) elicited a significant increase in circulating HSPCs that was comparable with the historical results from G-CSF plus the CXCR4 antagonist plerixafor. GPC-100 is currently being investigated for HSPC mobilization in combination with the FDA-approved ß-adrenergic receptor (ß-AR) blocker propranolol in a phase II clinical trial for autologous stem cell transplant (ASCT) in multiple myeloma. Here, we present preclinical findings indicating that the addition of propranolol to GPC-100 alone or GPC-100 and G-CSF combination can address the unmet needs of patients undergoing mobilization. Additionally, we show an enhanced and unique pattern of lymphoid cell mobilization that may have applications in adoptive cell therapies. Compared to chemotherapy, ASCT significantly improves survival in multiple myeloma patients. Because HSPCs constitute a very small fraction (~ 0.1%) of circulating mononuclear cells, it is critical to mobilize a sufficient number of HSPC into peripheral blood during the ASCT process. Current therapies for HSPC mobilization include G-CSF as a monotherapy or combined with plerixafor. However, mobilization failure is experienced by 15-50% patients, leading to potential loss of ASCT as a treatment option and significant toxicity from repeated mobilization attempts. Moreover, G-CSF is contraindicated in sickle cell disease and may exacerbate autoimmune diseases. Therefore, our goal is to identify novel strategies that will not only address the mobilization failure, but also explore non-G-CSF options for adequate mobilization. G protein-coupled receptors like CXCR4 can form heteromers with other receptors and result in altered signaling pathways. Using Proximity Ligation Assay in Namalwa (lymphoma) cells, we show that endogenously expressed CXCR4 and ß 2AR form heteromers, which are absent in CXCR4 knockout cells. In cell-based assays, co-activation of both receptors with their respective ligands, CXCL12 and epinephrine, leads to a synergistic increase in calcium flux (Figure 1) as well as ß-arrestin recruitment, indicating functional consequences of the heteromerization. Complete blockade of this enhanced signaling is only achieved with co-inhibition by both antagonists. Like CXCR4, ß 2AR is also expressed by HSPCs, and in lymph nodes was shown to heteromerize with CXCR4 to increase lymphocyte retention. In multiple myeloma patients, propranolol upregulated stem-cell like gene signature. Therefore, we sought to understand the effects of propranolol on HSPC mobilization by GPC-100. In mice, single injection of GPC-100 effectively mobilized hematopoietic stem cells characterized as Lin negSca1 +cKit +(LSK) cells as well as mature Lin negCD34 + progenitor cells by 2-4-fold, respectively. Seven-day pretreatment with propranolol enhanced LSK cell mobilization by GPC-100 resulting in a 4-fold increase in circulating HSPCs (Figure 2). Addition of propranolol to G-CSF and GPC-100 led to 8-17-fold increases in mobilization of long-term repopulating HSCs (CD34 negLSK and CD150 +LSK), which were greater than the 4-7-fold increases elicited by G-CSF and G-CSF with plerixafor. Additionally, propranolol enhanced GPC-100 induced mobilization of white blood cells, neutrophils, and lymphocytes (Figure 2). Immune cell subset analyses revealed that GPC-100 induced a 3-fold increase in circulating CD8 +T cells, which was increased to 7-fold when combined with propranolol (Figure 2). For comparison, plerixafor increased CD8 + T cell mobilization by only 2-fold. GPC-100 induced mobilization of NK and B cells was also improved by propranolol. These pre-clinical data support our phase II clinical trial currently in progress (NCT05561751). In the first arm of this two-arm trial, GPC-100 is combined with orally administered propranolol, and in the second arm, G-CSF is added to this combination. We anticipate that our clinical studies can fill the gap in the current standard of care without adding a significant financial burden or co-morbidities. Furthermore, enhanced mobilization of CD8+ T cells can provide extended opportunities for improved adoptive cell therapies.

Abstract 17537: Myocardial Dysfunction is Associated With Impaired Angiogenesis in Patients With Heart Failure With Preserved Ejection Fraction

Background: Recent evidence suggests that myocardial microvascular damage may represent a key parameter in the pathogenesis of heart failure with preserved ejection fraction (HFpEF). Aim: We sought to investigate a potential correlation between parameters of angiogenesis and myocardial dysfunction in HFpEF patients. Methods: We enrolled 30 consecutive HFpEF patients with NYHA class III, left ventricular ejection fraction (LVEF) >50%, E/e' >15, and NT-proBNP >300 pg/ml. In all patients endothelial progenitor cells (EPCs) were mobilized by granulocyte-colony stimulating factor (G-CSF; 10 mcg/kg, 5 days) and collected via apheresis. Before EPC mobilisation we performed echocardiography and measured plasma levels of biomarkers of angiogenesis. All patients underwent electroanatomical mapping for the measurement of myocardial viability; preserved viability was defined as mean unipolar voltage> 8.3 mV. Results: Myocardial viability was preserved in 11 patients (37%; Group A) and decreased in 19 patients (63%; Group B). The groups did not differ in age (63±10 years in Group A vs. 61±8 years in Group B, P=0.78), gender (male: 73% vs. 79%, P=0.70), serum creatinine (1.07±0.34 mg/dL vs. 1.04±0.40 mg/dL, P=0.43), or LVEF (60±7% vs. 57±4%, P=0.32). In Group B we found higher levels of NT-proBNP (2370±1020 pg/mL vs. 920±455 pg/mL in Group A, P=0.04) and E/e’ (23.2±3.1 vs. 17.4±1.8 pg/ in Group A, P=0.02). After G-CSF stimulation, we found significantly lower numbers of EPCs in Group B (53±42 x10 6 cells/L) than in Group A (102±52 x10 6 cells/L, P=0.001). Similarly, apheresis yielded lower numbers of EPCs in Group B (85±82 x10 6 cells vs. 200±93 x10 6 cells in Group A, P=0.003). When compared to Group A, patients in Group B displayed lower levels of pro-angiogenic biomarkers (agiopoietin-1: 7.4±2.8 ng/mL vs. 12.4±5.1 ng/mL, P=0.02; vascular endothelial growth factor: 27.5±20.1 pg/mL vs. 51.6±24.2 pg/mL, P=0.01), and higher levels of anti-angiogenic biomarkers (endostatin: 56.5±19.1 ng/mL vs. 33.2±14.3 ng/mL, P=0.01; thrombospondin-2: 16.4±4.3 ng/mL vs. 9.2±5.0 ng/mL, P=0.03). Conclusion: In patients with HFpEF, myocardial dysfunction appears to correlate with reduced mobilisation of endothelial progenitor cells and impaired angiogenesis.

Neuroplastic and Pro-cognitive Effects of Granulocyte Colony Stimulating Factor in Healthy Adults: A Pilot Study.

Granulocyte colony-stimulating factor (G-CSF) is a growth factor used to regulate the mobilization of bone marrow progenitor cells and has been shown to promote brain repair and reduce inflammation. This study aimed to investigate the pro-cognitive and neuroplastic effects of G-CSF in healthy adults. Sixteen healthy adults or donors of hematopoietic stem cell transplantation received G-CSF injections for 5 consecutive days, and their blood samples were collected before, immediately after, and 3 weeks after the G-CSF injections. Twelve subjects underwent neuropsychological testing before and 12 weeks after the G-CSF injections. The study found that G-CSF administration resulted in significant improvements in cognitive function, as measured by the Rey- Osterrieth Complex Figure test for immediate recall, delayed recall, and recognition score at 12 weeks after the injections. The blood levels of brain-derived neurotrophic factor, interleukin-4, and interleukin-8 were significantly increased immediately after the injections and returned to baseline levels after 3 weeks. There was no significant change in the plasma level of Multimer Detection System-oligomerized amyloid beta. Our results might suggest that G-CSF has neuroplastic and pro-cognitive effects in healthy adults. However, further study containing a larger sample size is needed to confirm our findings.

Acute psychological stress-induced progenitor cell mobilization and cardiovascular events

ObjectiveCertain brain activation responses to psychological stress are associated with worse outcomes in CVD patients. We hypothesized that elevated acute psychological stress, manifesting as greater activity within neural centers for emotional regulation, mobilizes CPC from the bone marrow to the peripheral blood and predicts future cardiovascular events. MethodsIn 427 patients with stable CAD undergoing a laboratory-based mental stress (MS) test, CPCs were enumerated using flow cytometry as CD34-expressing mononuclear cells (CD34+) before and 45 min after stress. Changes in brain regional blood flow with MS were measured using high resolution-positron emission tomography (HR-PET). Association between the change in CPC with MS and the risk of cardiovascular death or myocardial infarction (MI) during a 5-year follow-up period was analyzed. ResultsMS increased CPC counts by a mean of 150 [630] cells/mL (15%), P < 0.001. Greater limbic lobe activity, indicative of activation of emotion-regulating centers, was associated with greater CPC mobilization (P < 0.005). Using Fine and Gray models after adjustment for demographioc, clinical risk factors and medications use, greater CPC mobilization was associated with a higher adjusted risk of adverse events; a rise of 1000 cells/mL was associated with a 50% higher risk of cardiovascular death/MI [hazards ratio, 1.5, 95% confidence interval, 1.1–2.2). ConclusionGreater limbic lobe activity, brain areas involved in emotional regulation, is associated with MS-induced CPC mobilization. This mobilization isindependently associated with cardiovascular events. These findings provide novel insights into mechanisms through which psychological stressors modulate cardiovascular risk.

Exploration of the influence of early rehabilitation training on circulating endothelial progenitor cell mobilization in patients with acute ischemic stroke and its related mechanism under a lightweight artificial intelligence algorithm.

This work aimed to explore the application of lightweight artificial intelligence algorithms in magnetic resonance imaging (MRI) image processing of patients with acute ischemic stroke (AIS) to clarify the effect and mechanism of early rehabilitation training on the mobilization of circulating endothelial progenitor cells (EPCs) in AIS. A total of 98 AIS patients undergoing MRI examination were selected as the research objects and were randomly divided into a rehabilitation group (early rehabilitation training, 50 cases) and a routine group (conventional treatment, 48 cases) by random number table method and lottery method. In this work, based on the convolutional neural network (CNN) algorithm, a low-rank decomposition algorithm was introduced to optimize it, and a lightweight MRI image computer intelligent segmentation model (LT-RCNN) was established. The LT-RCNN model was used in the MRI image processing of AIS patients, and the role of the model in AIS image segmentation and lesion localization was analyzed. Furthermore, flow cytometry was used to detect the number of peripheral circulating EPCs and CD34+KDR+ cells in the two groups of patients before and after treatment. The serum levels of vascular endothelial growth factor (VEGF), tumor necrosis factor-α (TNF-α), interleukin 10 (IL-10), and stromal cell-derived factor-1α (SDF-1α) content were detected by Enzyme-Linked Immunosorbent Assay (ELISA). In addition, the correlation between each factor and CD34+KDR+ was analyzed by Pearson linear correlation. The diffusion-weighted imaging (DWI) signal of MRI images of AIS patients under the LT-RCNN model was high. The location of the lesion could be accurately detected, and the contour of the lesion could be displayed and segmented, and the segmentation accuracy and sensitivity were significantly better than before optimization. The number of EPCs and CD34+KDR+ cells in the rehabilitation group was increased compared with the control group (p<0.01); the expression levels of VEGF, IL-10, and SDF-1α were higher than those of the control group (p<0.001), and TNF-α content was lower than the control group (p<0.001). The number of CD34+KDR+ cells was positively correlated with VEGF, IL-10, and TNF-α contents (p<0.01). The results showed that the computer-intelligent segmentation model LT-RCNN could accurately locate, and segment AIS lesions and the early rehabilitation training could change the expression level of inflammatory factors and further promote the mobilization of AIS circulation EPCs.

Beyond brain injury biomarkers: chemoattractants and circulating progenitor cells as biomarkers of endogenous rehabilitation effort in preterm neonates with encephalopathy.

Preclinical work and studies in adults have shown that endogenous regeneration efforts that involve mobilization of progenitor cells take place after brain injury. However, kinetics of endogenous circulating progenitor cells (CPCs) in preterm neonates is not well described, particularly their possible role regarding brain injury and regeneration. We aimed to assess the kinetics of CPCs in neonates with encephalopathy of prematurity in relation to brain injury biomarkers, chemoattractants and relevant antenatal and postanal clinical factors, in an effort to outline the related pathophysiology. 47 preterm neonates (of 28-33 weeks GA) were enrolled: 31 newborns with no or minimal brain injury (grade I IVH) and 16 prematures with encephalopathy (grade III or IV IVH, PVL or infarct). Peripheral blood samples obtained on days 1, 3, 9, 18 and 45 after birth were analyzed using flow cytometry, focusing on EPCs (early and late Endothelial Progenitor Cells), HSCs (Hematopoietic Stem Cells) and VSELs (Very Small Embryonic-Like Stem Cells). At the same time-points serum levels of S100B, Neuron-specific Enolase (NSE), Erythropoietin (EPO), Insulin-like growth factor-1 (IGF-1) and SDF-1 were also measured. Neonates were assessed postnatally with brain MRI, and with Bayley III developmental test at 2 years of corrected age. Preterms with brain injury proved to have significant increase of S100B and NSE, followed by increase of EPO and enhanced mobilization mainly of HSCs, eEPCs and lEPCs. IGF-1 was rather decreased in this group of neonates. IGF-1 and most CPCs were intense decreased in cases of antenatal or postnatal inflammation. S100B and NSE correlated with neuroimaging and language scale in Bayley III test, providing good prognostic ability. The observed pattern of CPCs' mobilization and its association with neurotrophic factors following preterm brain injury indicate the existence of an endogenous brain regeneration process. Kinetics of different biomarkers and associations with clinical factors contribute to the understanding of the related pathophysiology and might help to early discriminate neonates with adverse outcome. Timely appropriate enhancement of the endogenous regeneration effort, when it is suppressed and insufficient, using neurotrophic factors and exogenous progenitor cells might be a powerful therapeutic strategy in the future to restore brain damage and improve the neurodevelopmental outcome in premature infants with brain injury.

Very short-term tissue coverage of the CD34 antibody-covered sirolimus-eluting stent: an optical coherence tomography study.

It is well known that patients with acute myocardial infarction (AMI) have delayed vessel healing despite accelerated endothelial progenitor cells (EPC) mobilization. The COMBO stent is a unique biodegradable-polymer sirolimus-eluting stent with an anti-CD34 antibody coating which captures EPC and potentially promotes vessel healing. However, there are limited data about strut tissue coverage at the very short-term period after COMBO stent implantation. This was a prospective study to investigate strut tissue coverage within 1month after COMBO stent implantation using optical coherence tomography (OCT). Struts fully covered with tissue were defined as covered, and struts with distance from lumen surface longer than strut plus polymer thickness were defined as malapposed. Mean tissue thickness was measured only in apposed struts. A total of 8173 struts of 33 lesions in 32 patients were analyzed at an average of 19.8 ± 4.6days after COMBO stent implantation. In lesion-level analysis, the rate of covered struts was 89.6 ± 7.2%, the rate of malapposed struts was 0.9 ± 2.0% and mean tissue thickness was 46.8 ± 14.3µm. In comparison between AMI (n = 12) and non-AMI (n = 21) patients, there were no significant differences in the rate of covered struts (88.4 ± 8.4% vs. 90.2 ± 6.6%, p = 0.48) and mean tissue thickness (46.8 ± 13.7µm vs. 46.9 ± 15.0µm, p = 0.98). Multivariable analysis demonstrated that time from implantation to OCT imaging was significantly associated with mean tissue thickness. The COMBO stent had substantial tissue coverage at the very short-term period after implantation even in AMI patients, and follow-up time had an impact on vessel healing.

DNA methylation changes underlie the long-term association between periodontitis and atherosclerotic cardiovascular disease.

Periodontitis, the leading cause of adult tooth loss, has been identified as an independent risk factor for cardiovascular disease (CVD). Studies suggest that periodontitis, like other CVD risk factors, shows the persistence of increased CVD risk even after mitigation. We hypothesized that periodontitis induces epigenetic changes in hematopoietic stem cells in the bone marrow (BM), and such changes persist after the clinical elimination of the disease and underlie the increased CVD risk. We used a BM transplant approach to simulate the clinical elimination of periodontitis and the persistence of the hypothesized epigenetic reprogramming. Using the low-density lipoprotein receptor knockout (LDLRo ) atherosclerosis mouse model, BM donor mice were fed a high-fat diet to induce atherosclerosis and orally inoculated with Porphyromonas gingivalis (Pg), a keystone periodontal pathogen; the second group was sham-inoculated. Naïve LDLR o mice were irradiated and transplanted with BM from one of the two donor groups. Recipients of BM from Pg-inoculated donors developed significantly more atherosclerosis, accompanied by cytokine/chemokines that suggested BM progenitor cell mobilization and were associated with atherosclerosis and/or PD. Using whole-genome bisulfite sequencing, 375 differentially methylated regions (DMRs) and global hypomethylation in recipients of BM from Pg-inoculated donors were observed. Some DMRs pointed to the involvement of enzymes with major roles in DNA methylation and demethylation. In validation assays, we found a significant increase in the activity of ten-eleven translocase-2 and a decrease in the activity of DNA methyltransferases. Plasma S-adenosylhomocysteine levels were significantly higher, and the S-adenosylmethionine to S-adenosylhomocysteine ratio was decreased, both of which have been associated with CVD. These changes may be related to increased oxidative stress as a result of Pg infection. These data suggest a novel and paradigm-shifting mechanism in the long-term association between periodontitis and atherosclerotic CVD.

Clonal hematopoiesis in patients with stem cell mobilization failure: a nested case-control study.

Inadequate mobilization of peripheral blood progenitor cells (PBPCs) is a limiting factor to proceeding with autologous hematopoietic cell transplantation (auto-HCT). To assess the impact of clonal hematopoiesis (CH) on mobilization failure of PBPC for auto-HCT, we investigated the characteristics of poor mobilizers (with a total PBPC collection <2× 106 CD34+ cells per kg) in a consecutive single-center cohort of 776 patients. Targeted error-corrected next-generation sequencing of 28 genes was performed in a nested case-control cohort of 90 poor mobilizers and 89 matched controls. CH was detected in 48 out of 179 patients (27%), with most patients carrying a single mutation. The presence of CH (detected at variant allele frequency [VAF] ≥ 1%) did not associate with poor mobilization potential (31% vs 22% in controls, odds ratio, 1.55; 95% confidence interval, 0.76-3.23; P= .238). PPM1D mutations were detected more often in poor mobilizers (P= .005). In addition, TP53 mutations in this cohort were detected exclusively in patients with poor mobilization potential (P= .06). The incidence of therapy-related myeloid neoplasms (t-MN) was higher among patients with mobilization failure (P= .014). Although poor mobilizers experienced worse overall survival (P= .019), this was not affected by the presence of CH. We conclude that CH at low VAF (1%-10%) is common at the time of stem cell mobilization. TP53 mutations and PPM1D mutations are associated with poor mobilization potential and their role in subsequent development of t-MN in these individuals should be established.

Genistein, a Soybean Isoflavone, Promotes Wound Healing by Enhancing Endothelial Progenitor Cell Mobilization in Rats with Hemorrhagic Shock.

Severe trauma and hemorrhaging are often accompanied by delayed cutaneous wound healing. Soybean isoflavone is a natural phytoestrogen that has attracted great attention due to its protective effects against various injuries. Endothelial progenitor cells (EPCs) are precursor cells with directional differentiation characteristics. This study is to determine whether genistein (GEN), an isoflavone in soybean products, benefits wound healing in hemorrhagic shock (HS) rats by promoting EPC homing and to investigate the underlying mechanisms. In this study, it isfound that GEN promotes skin wound healing in HS rats, which is due at least partly to the mobilization of endogenous EPCs to the injury site via angiotensin II (Ang-II), stromal cell-derived factor-1alpha (SDF-1α), and transforming growth factor beta(TGF-β) signaling.

Endothelial progenitor cell mobilization based on exercise volume in patients with cardiovascular disease and healthy individuals: a systematic review and meta-analysis.

Endothelial progenitor cells (EPCs) play a vital role in protecting endothelial dysfunction and cardiovascular disease (CVD). Physical exercise stimulates the mobilization of EPCs, and along with vascular endothelial growth factor (VEGF), promotes EPC differentiation, and contributes to vasculogenesis. The present meta-analysis examines the exercise-induced EPC mobilization and has an impact on VEGF in patients with CVD and healthy individuals. Database research was conducted (PubMed, EMBASE, Cochrane Library of Controlled Trials) by using an appropriate algorithm to indicate the exercise-induced EPC mobilization studies. Eligibility criteria included EPC measurements following exercise in patients with CVD and healthy individuals. A continuous random effect model meta-analysis (PROSPERO-CRD42019128122) was used to calculate mean differences in EPCs (between baseline and post-exercise values or between an experimental and control group). A total of 1460 participants (36 studies) were identified. Data are presented as standard mean difference (Std.MD) and 95% confidence interval (95% CI). Aerobic training stimulates the mobilization of EPCs and increases VEGF in patients with CVD (EPCs: Std.MD: 1.23, 95% CI: 0.70-1.76; VEGF: Std.MD: 0.76, 95% CI:0.16-1.35) and healthy individuals (EPCs: Std.MD: 1.11, 95% CI:0.53-1.69; VEGF: Std.MD: 0.75, 95% CI: 0.01-1.48). Acute aerobic exercise (Std.MD: 1.40, 95% CI: 1.00-1.80) and resistance exercise (Std.MD: 0.46, 95%CI: 0.10-0.82) enhance EPC numbers in healthy individuals. Combined aerobic and resistance training increases EPC mobilization (Std.MD:1.84, 95% CI: 1.03-2.64) in patients with CVD. Adequate exercise volume (>60%VO2max >30 min; P = 0.00001) yields desirable results. Our meta-analysis supports the findings of the literature. Exercise volume is required to obtain clinically significant results. Continuous exercise training of high-to-moderate intensity with adequate duration as well as combined training with aerobic and resistance exercise stimulates EPC mobilization and increases VEGF in patients with CVD and healthy individuals.

Mobilization of Hematopoietic Stem and Progenitor Cells during Dengue Virus Infection.

Hematopoietic stem and progenitor cells (HSPCs) mobilization is the movement of HSPCs from the bone marrow to the peripheral blood or tissue induced by stress. HSPC mobilization is a well-known response to protect the host during infection through urgent differentiation of HSPCs to immune cells. Dengue virus (DENV) infection is known to cause stress in infected humans and the mobilizing capacity of HSPCs during DENV infection in affected patients has not been fully investigated. Here, we investigated whether DENV infection can induce HSPC mobilization and if the mobilized HSPCs are permissive to DENV infection. White blood cells (WBCs) were collected from dengue patients (DENV+) and healthy donors and analyzed by flow cytometry and plaque assay. Elevated HSPCs levels were found in the WBCs of the DENV+ group when compared to the healthy group. Mobilization of HSPCs and homing markers (skin and gut) expression decreased as the patients proceeded from dengue without symptoms (DWoWS) to severe dengue (SD). Mobilizing HSPCs were not only permissive to DENV infection, but infectious DENV could be recovered after coculture. Our results highlight the need for further investigation into HSPC mobilization or alterations of hematopoiesis during viral infections such as DENV in order to develop appropriate countermeasures.

Optimized Small Molecule VLA-4 Inhibitors for Hematopoietic Stem and Progenitor Cell Mobilization

Optimized Small Molecule VLA-4 Inhibitors for Hematopoietic Stem and Progenitor Cell Mobilization

GDF11 promotes wound healing in diabetic mice via stimulating HIF-1ɑ-VEGF/SDF-1ɑ-mediated endothelial progenitor cell mobilization and neovascularization.

Non-healing diabetic wounds (DW) are a serious clinical problem that remained poorly understood. We recently found that topical application of growth differentiation factor 11 (GDF11) accelerated skin wound healing in both Type 1 DM (T1DM) and genetically engineered Type 2 diabetic db/db (T2DM) mice. In the present study, we elucidated the cellular and molecular mechanisms underlying the action of GDF11 on healing of small skin wound. Single round-shape full-thickness wound of 5-mm diameter with muscle and bone exposed was made on mouse dorsum using a sterile punch biopsy 7 days following the onset of DM. Recombinant human GDF11 (rGDF11, 50 ng/mL, 10 μL) was topically applied onto the wound area twice a day until epidermal closure (maximum 14 days). Digital images of wound were obtained once a day from D0 to D14 post-wounding. We showed that topical application of GDF11 accelerated the healing of full-thickness skin wounds in both type 1 and type 2 diabetic mice, even after GDF8 (a muscle growth factor) had been silenced. At the cellular level, GDF11 significantly facilitated neovascularization to enhance regeneration of skin tissues by stimulating mobilization, migration and homing of endothelial progenitor cells (EPCs) to the wounded area. At the molecular level, GDF11 greatly increased HIF-1ɑ expression to enhance the activities of VEGF and SDF-1ɑ, thereby neovascularization. We found that endogenous GDF11 level was robustly decreased in skin tissue of diabetic wounds. The specific antibody against GDF11 or silence of GDF11 by siRNA in healthy mice mimicked the non-healing property of diabetic wound. Thus, we demonstrate that GDF11 promotes diabetic wound healing via stimulating endothelial progenitor cells mobilization and neovascularization mediated by HIF-1ɑ-VEGF/SDF-1ɑ pathway. Our results support the potential of GDF11 as a therapeutic agent for non-healing DW.