Lineage-specific hematopoietic growth factors

Emerging platelet-based drug delivery systems

Drug delivery systems are becoming increasingly utilized; however, a major challenge in this field is the insufficient target of tissues or cells. Although efforts with engineered nanoparticles have shown some success, issues with targeting, toxicity and immunogenicity persist. Conversely, living cells can be used as drug-delivery vehicles because they typically have innate targeting mechanisms and minimal adverse effects. As active participants in hemostasis, inflammation, and tumors, platelets have shown great potential in drug delivery. This review highlights platelet-based drug delivery systems, including platelet membrane engineering, platelet membrane coating, platelet cytoplasmic drug loading, genetic engineering, and synthetic/artificial platelets for different applications.

Assessment of medullary and extramedullary myelopoiesis in cardiovascular diseases

Recruitment of innate immune cells and their accumulation in the arterial wall and infarcted myocardium has been recognized as a central feature of atherosclerosis and cardiac ischemic injury, respectively. In both, steady state and under pathological conditions, majority of these cells have a finite life span and are continuously replenished from haematopoietic stem/progenitor cell pool residing in the bone marrow and extramedullary sites. While having a crucial role in the cardiovascular disease development, proliferation and differentiation of innate immune cells within haematopoietic compartments is greatly affected by the ongoing cardiovascular pathology. In the current review, we summarize key cells, processes and tissue compartments that are involved in myelopoiesis under the steady state, during atherosclerosis development and in myocardial infarction.

Randomized and dose-escalation trials of recombinant human serum albumin /granulocyte colony-stimulating factor in patients with breast cancer receiving anthracycline-containing chemotherapy

BACKGROUND

To evaluate the efficacy and safety of recombinant human serum albumin /granulocyte colony-stimulating factor (rHSA/G-CSF) in breast cancer following receipt of cytotoxic agents.

METHODS

The phase 1b trial assessed the pharmacokinetics, pharmacodynamics, and safety of dose-escalation, ranging from rHSA/G-CSF 1800 μg, 2100 μg, and 2400 μg. Randomized controlled phase 2b trial was further conducted to ensure the comparative efficacy and safety of rHSA/G-CSF 2400 μg and rhG-CSF 5 μg/kg. In multicenter, randomized, open-label, parallel, phase 2 study, participants treated with anthracycline-containing chemotherapy were assigned in a ratio 1:1:1 to receive double delivery of rHSA/G-CSF 1200 μg, 1500 μg, and continuous rhG-CSF 5 μg/kg.

RESULTS

Between December 16, 2014, to July 23, 2018, a total of 320 patients were enrolled, including 25 individuals in phase 1b trial, 80 patients in phase 2b trial, and 215 participants in phase 2 study. The mean duration of agranulocytosis during the first chemotherapeutic intermission was observed as 1.14 ± 1.35 days in rHSA/G-CSF 1500 μg, which was comparable with that of 1.07 ± 0.97 days obtained in rhG-CSF control (P = 0.71). Safety profiles were assessed to be acceptable ranging from rHSA/G-CSF 1800 μg to 2400 μg, while the double delivery of HSA/G-CSF 2400 μg failed to meet the noninferiority in comparison with rhG-CSF.

CONCLUSION

The prospective randomized controlled trials demonstrated that rHSA/G-CSF was efficacious and well-tolerated with an approachable frequency and expense of application for prophylactic management of agranulocytosis. The double delivery of rHSA/G-CSF 1500 μg in comparisons with paralleling G-CSF preparations is warranted in the phase 3 trial.

TRIAL REGISTRATION

ClinicalTrials.gov identifiers: NCT02465801 (11/17/2014), NCT03246009 (08/08/2017), NCT03251768 (08/07/2017).

Molecular and cellular mechanisms of aging in hematopoietic stem cells and their niches

Aging drives the genetic and epigenetic changes that result in a decline in hematopoietic stem cell (HSC) functioning. Such changes lead to aging-related hematopoietic/immune impairments and hematopoietic disorders. Understanding how such changes are initiated and how they progress will help in the development of medications that could improve the quality life for the elderly and to treat and possibly prevent aging-related hematopoietic diseases. Here, we review the most recent advances in research into HSC aging and discuss the role of HSC-intrinsic events, as well as those that relate to the aging bone marrow niche microenvironment in the overall processes of HSC aging. In addition, we discuss the potential mechanisms by which HSC aging is regulated.

Steamed Panax notoginseng Attenuates Anemia in Mice With Blood Deficiency Syndrome via Regulating Hematopoietic Factors and JAK-STAT Pathway

Panax notoginseng (Burk.) F. H. Chen is a medicinal herb used to treat blood disorders since ancient times, of which the steamed form exhibits the anti-anemia effect and acts with a “blood-tonifying” function according to traditional use. The present study aimed to investigate the anti-anemia effect and underlying mechanism of steamed P. notoginseng (SPN) on mice with blood deficiency syndrome induced by chemotherapy. Blood deficiency syndrome was induced in mice by cyclophosphamide and acetylphenylhydrazine. A number of peripheral blood cells and organs (liver, kidney, and spleen) coefficients were measured. The mRNA expression of hematopoietic function-related cytokines in the bone marrow of mice was detected by RT-qPCR. The janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway was screened based on our previous analysis by network pharmacology. The expression of related proteins and cell cycle factors predicted in the pathway was determined by Western blot and RT-qPCR. SPN could significantly increase the numbers of peripheral blood cells and reverse the enlargement of spleen in a dose-dependent manner. The quantities of related hematopoietic factors in bone marrow were also increased significantly after SPN administration. SPN was involved in the cell cycle reaction and activation of immune cells through the JAK-STAT pathway, which could promote the hematopoiesis.

Platelet-secreted microRNA-223 promotes endothelial cell apoptosis induced by advanced glycation end products via targeting the insulin-like growth factor 1 receptor

Platelets play a significant role in atherosclerosis, stroke, and asthma through active interaction with neutrophils, monocytes, and vascular endothelial cells. The mechanism underlying these intercellular interactions, however, is incompletely understood. In this study, we report that platelets can remotely modulate vascular endothelial cell apoptosis through releasing microRNA-223 (miR-223)-containing microvesicles (MVs). First, platelets expressed abundant miRNAs, and miR-223 had the highest level of expression. Platelet miR-223 and other miRNAs can be upregulated by the stimulation with thrombopoietin (TPO) or thrombin. Unlike leukocytes, platelets contained high levels of pre-miRNAs, and upregulation of mature platelet miRNAs by TPO was correlated with decreased pre-miRNAs. Second, under stimulation with TPO, platelets released a large amount of MVs, which also contain higher levels of miR-223. Elevation of miR-223 inside circulating platelet MVs (P-MVs) was also observed in plasma samples from patients with enteritis, hepatitis, nephritis, or atherosclerosis. Third, incubation of P-MVs with HUVECs, which had significantly lower levels of miR-223 than platelets, showed that P-MVs effectively delivered miR-223 into HUVECs. Finally, in HUVECs, exogenous platelet miR-223 decreased the level of insulin-like growth factor 1 receptor and thus promoted HUVEC apoptosis induced by advanced glycation end products. The proapoptotic effect of P-MVs on HUVECs was largely abolished by depleting cellular miR-223 using anti-miR-223 antisense oligonucleotide. In conclusion, our study presents the first evidence, to our knowledge, that platelet-released miR-223 promotes advanced glycation end product-induced vascular endothelial cell apoptosis via targeting insulin-like growth factor 1 receptor.

Repeated lentivirus-mediated granulocyte colony-stimulating factor administration to treat canine cyclic neutropenia

Cyclic neutropenia occurs in humans and gray collie dogs, is characterized by recurrent neutropenia, and is treated by repeated injections of recombinant granulocyte colony-stimulating factor (rG-CSF). As dose escalation of lentivirus may be clinically necessary, we monitored the outcome of four sequential intramuscular injections of G-CSF-lentivirus (3 × 10(7) IU/kg body weight) to a normal dog and a gray collie. In the normal dog absolute neutrophil counts were significantly increased after each dose of virus, with mean levels of 27.75 ± 3.00, 31.50 ± 1.40, 35.05 ± 1.68, and 43.88 ± 2.94 × 10(3) cells/μl, respectively (p<0.001), and elevated neutrophil counts of 31.18 ± 7.81 × 10(3) cells/μl were maintained for more than 6 years with no adverse effects. A gray collie dog with a mean count of 1.94 ± 1.48 × 10(3) cells/μl received G-CSF-lentivirus and we observed sustained elevations in neutrophil levels for more than 5 months with a mean of 26.00 ± 11.00 × 10(3) cells/μl, significantly increased over the pretreatment level (p<0.001). After the second and third virus administrations mean neutrophil counts of 15.80 ± 6.14 and 11.52 ± 4.90 × 10(3) cells/μl were significantly reduced compared with cell counts after the first virus administration (p<0.001). However, after the fourth virus administration mean neutrophil counts of 15.21 ± 4.50 × 10(3) cells/μl were significantly increased compared with the previous administration (p<0.05). Throughout the nearly 3 years of virus administrations the dog gained weight, was healthy, and showed neutrophil counts significantly higher than pretreatment levels (p<0.001). These studies suggest that patients with cyclic and other neutropenias may be treated with escalating doses of G-CSF-lentivirus to obtain a desired therapeutic neutrophil count.