Numerous growth factors, cytokines, and chemokines are secreted by human CD34(+) cells, myeloblasts, erythroblasts, and megakaryoblasts and regulate normal hematopoiesis in an autocrine/paracrine manner

Transplantation of human umbilical cord blood mononuclear cells promotes functional endometrium reconstruction via downregulating EMT in damaged endometrium

Introduction

Cell transplantation is an emerging and effective therapeutic approach for enhancing uterine adhesions caused by endometrial damage. Currently, human umbilical cord blood mononuclear cells (HUCBMCs) have been extensively for tissue and organ regeneration. However, their application in endometrial repair remains unexplored. Our investigation focuses on the utilization of HUCBMCs for treating endometrial injury.

Methods

The HUCBMCs were isolated from health umbilical cord blood, and co-cultured with the injured endometrial stromal cells and injured endometrial organoids. The cell proliferation and apoptosis were measured by cck8 assays and flow cytometry. Western blotting was used to detect the expression of PTEN, AKT and p-AKT. Immunofluorescence assay revealed expression levels of epithelial-mesenchymal transition (EMT) -related markers such as E-cadherin, N-cadherin, and TGF-β1. The endometrial thickness, fibrosis level, and glandular number were examined after the intravenous injection of HUCBMCs in mouse endometrial models. Immunohistochemistry was employed to assess changes in growth factors vascular endothelial growth factor (VEGF) and insulin-like growth factor 1 (IGF-1) as well as fibrosis markers α-SMA and COL1A1. Additionally, expressions of EMT-related proteins E-cadherin and N-cadherin were evaluated.

Results

HUCBMCs significantly improved the proliferation and reduced the apoptosis of damaged endometrial stromal cells (ESCs), accompanied by up-regulation of phospho-AKT expression. HUCBMCs increased endometrial thickness and glandular count while decreasing fibrosis and EMT-related markers in mouse endometrial models. Furthermore, EMT-related markers of ESCs and endometrial organoids were significantly decreased.

Conclusions

Our findings suggest that HUCBMCs plays a pivotal role in mitigating endometrial injury through the attenuation of fibrosis. HUCBMCs may exert a reverse effect on the EMT process during the endometrium reconstruction.

Heparan sulfates and heparan sulfate proteoglycans in hematopoiesis

ABSTRACT

From signaling mediators in stem cells to markers of differentiation and lineage commitment to facilitators for the entry of viruses, such as HIV-1, cell surface heparan sulfate (HS) glycans with distinct modification patterns play important roles in hematopoietic biology. In this review, we provide an overview of the importance of HS and the proteoglycans (HSPGs) to which they are attached within the major cellular subtypes of the hematopoietic system. We summarize the roles of HSPGs, HS, and HS modifications within each main hematopoietic cell lineage of both myeloid and lymphoid arms. Lastly, we discuss the biological advances in the detection of HS modifications and their potential to further discriminate cell types within hematopoietic tissue.

Bone Marrow Nucleated Cells and Bone Marrow-Derived CD271+ Mesenchymal Stem Cell in Treatment of Encephalopathy and Drug-Resistant Epilepsy

The broad spectrum of brain injuries in preterm newborns and the plasticity of the central nervous system prompts us to seek solutions for neurodegeneration to prevent the consequences of prematurity and perinatal problems. The study aimed to evaluate the safety and efficacy of the implantation of autologous bone marrow nucleated cells and bone marrow mesenchymal stem cells in different schemes in patients with hypoxic-ischemic encephalopathy and immunological encephalopathy. Fourteen patients received single implantation of bone marrow nucleated cells administered intrathecally and intravenously, followed by multiple rounds of bone marrow mesenchymal stem cells implanted intrathecally, and five patients were treated only with repeated rounds of bone marrow mesenchymal stem cells. Seizure outcomes improved in most cases, including fewer seizures and status epilepticus and reduced doses of antiepileptic drugs compared to the period before treatment. The neuropsychological improvement was more frequent in patients with hypoxic-ischemic encephalopathy than in the immunological encephalopathy group. Changes in emotional functioning occurred with similar frequency in both groups of patients. In the hypoxic-ischemic encephalopathy group, motor improvement was observed in all patients and the majority in the immunological encephalopathy group. The treatment had manageable toxicity, mainly mild to moderate early-onset adverse events. The treatment was generally safe in the 4-year follow-up period, and the effects of the therapy were maintained after its termination.

Interleukin-6 and interleukin-8 levels in children with aplastic anemia and its correlation with disease severity and response to immunosuppressive therapy

Background

Aplastic anemia (AA) is an uncommon condition characterized by pancytopenia and hypocellular bone marrow. Interleukin (IL)-6 and IL-8 have been shown to inhibit myelopoiesis and are major mediators of tissue damage. The primary goal of this study was to determine the IL-6 and IL-8 levels in children with AA, as well as their relationship to illness severity and immunosuppressive medication response.

Materials and Methods

The IL-6 and IL-8 levels were tested in 50 children aged 3-18 years who had AA. As controls, 50 healthy age and sex matched individuals were used. A sandwich enzyme-linked immunosorbent assay kit (solid-phase) was used to measure IL-6 and IL-8 levels quantitatively. The concentrations of IL-6 and IL-8 in pg/mL were used to represent the results. Immunosuppressive medication was given to the patients in accordance with the British Committee for Standards in Haematology Guidelines 2009.

Results

The patients' average age was 11.3 ± 3.7 years. Patients with AA had significantly higher IL-6 and IL-8 levels than controls (278.88 ± 216.03 vs. 4.51 ± 3.26; P < 0.001) and (120.28 ± 94.98 vs. 1.79 ± 0.78; P < 0.001), respectively. The IL-6 and IL-8 levels were also investigated with respect to AA severity, with statistically significant differences (P < 0.01) between different grading strata. Patients with very severe AA (VSAA) had the highest IL-6 levels (499.52 ± 66.19), followed by severe AA (SAA) (201.28 ± 157.77) and non-SAA (NSAA) (22.62 ± 14.63). For IL-8 levels, a similar trend (P < 0.01) was detected, with values of 209.81 ± 38.85, 92.12 ± 78.0, and 9.29 ± 10.68 for VSAA, SAA, and NSAA, respectively. After 6 months of immunosuppressive treatment (IST), mean levels of IL-6 and IL-8 in responders and nonresponders were again assessed. The mean IL-6 level in the responders' group (46.50 ± 45.41) was significantly lower, when compared to the nonresponders' group (145.76 ± 116.32) (P < 0.001). Similarly, the mean IL-8 level in the responder's group (33.57 ± 27.14) was significantly lower, compared to the nonresponder's group (97.49 ± 69.00) (P < 0.001).

Conclusions

Children with AA had higher IL-6 and IL-8 levels than normal age- and sex-matched controls. Increased levels were linked to the severity of the condition, suggesting that IL may have a role in AA. IL levels can be monitored in AA patients during IST, which can assist in predicting response to IST.

A comprehensive analysis of cell-autonomous and non-cell-autonomous regulation of myeloid leukemic cells: The prospect of developing novel niche-targeting therapies

Leukemic cells (LCs) arise from the hematopoietic stem/and progenitor cells (HSCs/HSPCs) and utilize cues from the bone marrow microenvironment (BMM) for their regulation in the same way as their normal HSC counterparts. Mesenchymal stromal cells (MSCs), a vital component of the BMM promote leukemogenesis by creating a protective and immune-tolerant microenvironment that can support the survival of LCs, helping them escape chemotherapy, thereby resulting in the relapse of leukemia. Conversely, MSCs also induce apoptosis in the LCs and inhibit their proliferation by interfering with their self-renewal potential. This review discusses the work done so far on cell-autonomous (intrinsic) and MSCs-mediated non-cell-autonomous (extrinsic) regulation of myeloid leukemia with a special focus on the need to investigate the extrinsic regulation of myeloid leukemia to understand the contrasting role of MSCs in leukemogenesis. These mechanisms could be exploited to formulate novel therapeutic strategies that specifically target the leukemic microenvironment.

Transcriptome Changes of Hematopoietic Stem and Progenitor Cells in the Peripheral Blood of COVID-19 Patients by scRNA-seq

Coronavirus disease 2019 (COVID-19) threatens public health all over the world. It is well-accepted that the immune cells in peripheral blood are widely involved in the pathological process of COVID-19. However, hematopoietic stem and progenitor cells (HSPCs), as the main source of peripheral immune cells, have not been well studied during COVID-19 infection. We comprehensively revealed the transcriptome changes of peripheral blood HSPCs after COVID-19 infection and vaccination by single-cell RNA-seq. Compared with healthy individuals, the proportion of HSPCs in COVID-19 patients significantly increased. The increase in the proportion of HSPCs might be partly attributed to the enhancement of the HSPCs proliferation upon COVID-19 infection. However, the stemness damage of HSPCs is reflected by the decrease of differentiation signal, which can be used as a potential specific indicator of the severity and duration of COVID-19 infection. Type I interferon (IFN-I) and translation signals in HSPCs were mostly activated and inhibited after COVID-19 infection, respectively. In addition, the response of COVID-19 vaccination to the body is mild, while the secondary vaccination strengthens the immune response of primary vaccination. In conclusion, our study provides new insights into understanding the immune mechanism of COVID-19 infection.

Imidazolyl Ethanamide Pentandioic Acid (IEPA) as Potential Radical Scavenger during Tumor Therapy in Human Hematopoietic Stem Cells

Radiochemotherapy-associated leuco- or thrombocytopenia is a common complication, e.g., in head and neck cancer (HNSCC) and glioblastoma (GBM) patients, often compromising treatments and outcomes. Currently, no sufficient prophylaxis for hematological toxicities is available. The antiviral compound imidazolyl ethanamide pentandioic acid (IEPA) has been shown to induce maturation and differentiation of hematopoietic stem and progenitor cells (HSPCs), resulting in reduced chemotherapy-associated cytopenia. In order for it to be a potential prophylaxis for radiochemotherapy-related hematologic toxicity in cancer patients, the tumor-protective effects of IEPA should be precluded. In this study, we investigated the combinatorial effects of IEPA with radio- and/or chemotherapy in human HNSCC and GBM tumor cell lines and HSPCs. Treatment with IEPA was followed by irradiation (IR) or chemotherapy (ChT; cisplatin, CIS; lomustine, CCNU; temozolomide, TMZ). Metabolic activity, apoptosis, proliferation, reactive oxygen species (ROS) induction, long-term survival, differentiation capacity, cytokine release, and DNA double-strand breaks (DSBs) were measured. In tumor cells, IEPA dose-dependently diminished IR-induced ROS induction but did not affect the IR-induced changes in metabolic activity, proliferation, apoptosis, or cytokine release. In addition, IEPA showed no protective effect on the long-term survival of tumor cells after radio- or chemotherapy. In HSPCs, IEPA alone slightly enhanced CFU-GEMM and CFU-GM colony counts (2/2 donors). The IR- or ChT-induced decline of early progenitors could not be reversed by IEPA. Our data indicate that IEPA is a potential candidate for the prevention of hematologic toxicity in cancer treatment without affecting therapeutic benefits.

Reversal of aging-associated increase in myelopoiesis and expression of alarmins by angiotensin-(1-7)

Aging is associated with chronic systemic inflammation largely due to increased myelopoiesis, which in turn increases risk for vascular disease. We have previously shown evidence for the therapeutic potential of Angiotensin-(1-7) (Ang-(1-7)) in reversing vasoreparative dysfunction in aging. This study tested the hypothesis that ischemic vascular repair in aging by Ang-(1-7) involves attenuation of myelopoietic potential in the bone marrow and decreased mobilization of inflammatory cells. Young or Old male mice of age 3-4 and 22-24 months, respectively, received Ang-(1-7) (1 µg/kg/min, s.c.) for four weeks. Myelopoiesis was evaluated in the bone marrow (BM) cells by carrying out the colony forming unit (CFU-GM) assay followed by flow cytometry of monocyte-macrophages. Expression of pro-myelopoietic factors and alarmins in the hematopoietic progenitor-enriched BM cells was evaluated. Hindlimb ischemia (HLI) was induced by femoral ligation, and mobilization of monocytes into the blood stream was determined. Blood flow recovery was monitored by Laser Doppler imaging and infiltration of inflammatory cells was evaluated by immunohistochemistry. BM cells from Old mice generated a higher number of monocytes (Ly6G-CD11b+Ly6Chi) and M1 macrophages (Ly6ChiF4/80+) compared to that of Young, which was reversed by Ang-(1-7). Gene expression of selected myelopoietic factors, alarmins (S100A8, S100A9, S100A14 and HMGb1) and the receptor for alarmins, RAGE, was higher in the Old hematopoietic progenitor-enriched BM cells compared to the Young. Increased expressions of these factors were decreased by Ang-(1-7). Ischemia-induced mobilization of monocytes was higher in Old mice with decreased blood flow recovery and increased infiltration of monocyte-macrophages compared to the Young, all of which were reversed by Ang-(1-7). Enhanced ischemic vascular repair by Ang-(1-7) in aging is largely by decreasing the generation and recruitment of inflammatory monocyte-macrophages to the areas of ischemic injury. This is associated with decreased alarmin signaling in the BM-hematopoietic progenitor cells.

CD34 positive cells as endothelial progenitor cells in biology and medicine

CD34 is a cell surface antigen expressed in numerous stem/progenitor cells including hematopoietic stem cells (HSCs) and endothelial progenitor cells (EPCs), which are known to be rich sources of EPCs. Therefore, regenerative therapy using CD34⁺ cells has attracted interest for application in patients with various vascular, ischemic, and inflammatory diseases. CD34⁺ cells have recently been reported to improve therapeutic angiogenesis in a variety of diseases. Mechanistically, CD34⁺ cells are involved in both direct incorporation into the expanding vasculature and paracrine activity through angiogenesis, anti-inflammatory, immunomodulatory, and anti-apoptosis/fibrosis roles, which support the developing microvasculature. Preclinical, pilot, and clinical trials have well documented a track record of safety, practicality, and validity of CD34⁺ cell therapy in various diseases. However, the clinical application of CD34⁺ cell therapy has triggered scientific debates and controversies in last decade. This review covers all preexisting scientific literature and prepares an overview of the comprehensive biology of CD34⁺ cells as well as the preclinical/clinical details of CD34⁺ cell therapy for regenerative medicine.

Isthmin-A Multifaceted Protein Family

Isthmin (ISM) is a secreted protein family with two members, namely ISM1 and ISM2, both containing a TSR1 domain followed by an AMOP domain. Its broad expression pattern suggests diverse functions in developmental and physiological processes. Over the past few years, multiple studies have focused on the functional analysis of the ISM protein family in several events, including angiogenesis, metabolism, organ homeostasis, immunity, craniofacial development, and cancer. Even though ISM was identified two decades ago, we are still short of understanding the roles of the ISM protein family in embryonic development and other pathological processes. To address the role of ISM, functional studies have begun but unresolved issues remain. To elucidate the regulatory mechanism of ISM, it is crucial to determine its interactions with other ligands and receptors that lead to the activation of downstream signalling pathways. This review provides a perspective on the gene organization and evolution of the ISM family, their links with developmental and physiological functions, and key questions for the future.

Comparative Evaluation of Platelet-rich Fibrin and Concentrated Growth Factor as Scaffolds in Regenerative Endodontic Procedure: A Randomized Controlled Clinical Trial

AIM

This randomized controlled trial evaluated the efficacy of platelet-rich fibrin (PRF) and concentrated growth factor (CGF) as scaffolds in the regenerative endodontic procedure (REP) using clinical and radiographic parameters along with cone-beam computed tomographic (CBCT) analysis.

MATERIALS AND METHODS

The apexogenesis procedure was performed in 16 teeth. They were randomly divided into two groups of eight teeth each: group I and group II. In group I PRF was used as the scaffold and in group II CGF was used as the scaffold. They were evaluated for pain, pulpal vitality, tenderness on percussion, and mobility, and also evaluated using digital radiographs at 3, 6, 12, and 18 months interval. The response of the teeth was graded using Chen and Chen criteria. Increase in root length, reduction in the apical foramen dimension, and reduction in periapical lesion volume were evaluated using CBCT scans taken preoperatively and at 18 months.

RESULTS

At the end of 3 months, 50% of teeth without periapical pathology were found to be vital in both groups. At the end of 18 months, 60% of the teeth in both groups showed increase in root length, all teeth showed closure of apical foramen, and reduction in the volume of periapical lesion. However, there was no statistically significant difference between the groups (p < 0.05).

CONCLUSION

The clinical and radiographic features reported in this study revealed that both PRF and CGF act as effective scaffolds in REP for regeneration of pulp-dentin complex with promising results.

CLINICAL SIGNIFICANCE

Apexogenesis by revascularization has not been used regularly for the treatment of nonvital teeth with open apex because the results are not reliable. Since platelet concentrates like PRF and CGF are rich in growth factors; when apexogenesis is performed by REP using these platelet concentrates, desirable results can be achieved in a short duration of time. They also accelerate the healing of periapical lesions present in such cases. With the increased success rate of apexogenesis with REP, many clinicians would prefer to use REPs as a treatment option for teeth with open apex.

Chemokines network in bone metastasis: Vital regulators of seeding and soiling

Chemokines are well equipped with chemo-attractive signals that can regulate cancer cell trafficking to specific organ sites. Currently, updated concepts have revealed the diverse role of chemokines in the biology of cancer initiation and progression. Genomic instabilities and alterations drive tumor heterogeneity, providing more options for the selection and metastatic progression to cancer cells. Tumor heterogeneity and acquired drug resistance are the main obstacles in managing cancer therapy and the primary root cause of metastasis. Studies emphasize that multiple chemokine/receptor axis are involved in cancer cell-mediated organ-specific distant metastasis. One of the persuasive mechanisms for heterogeneity and subsequent events is sturdily interlinked with the crosstalk between chemokines and their receptors on cancer cells and tissue-specific microenvironment. Among different metastatic niches, skeletal metastasis is frequently observed in the late stages of prostate, breast, and lung cancer and significantly reduces the survival of cancer patients. Therefore, it is crucial to elucidate the role of chemokines and their receptors in metastasis and bone remodeling. Here, we review the potential chemokine/receptor axis in tumorigenesis, tumor heterogeneity, metastasis, and vicious cycle in bone microenvironment.

Erythropoiesis and Malaria, a Multifaceted Interplay

One of the major pathophysiologies of malaria is the development of anemia. Although hemolysis and splenic clearance are well described as causes of malarial anemia, abnormal erythropoiesis has been observed in malaria patients and may contribute significantly to anemia. The interaction between inadequate erythropoiesis and Plasmodium parasite infection, which partly occurs in the bone marrow, has been poorly investigated to date. However, recent findings may provide new insights. This review outlines clinical and experimental studies describing different aspects of ineffective erythropoiesis and dyserythropoiesis observed in malaria patients and in animal or in vitro models. We also highlight the various human and parasite factors leading to erythropoiesis disorders and discuss the impact that Plasmodium parasites may have on the suppression of erythropoiesis.

Emerging roles of platelet concentrates and platelet-derived extracellular vesicles in regenerative periodontology and implant dentistry

Platelet concentrates (PCs) are easily obtained from autogenous whole blood after centrifugation and have evolved through three generations of development to include platelet-rich plasma, platelet-rich fibrin, and concentrated growth factor. Currently, PCs are widely used for sinus floor elevation, alveolar ridge preservation, periodontal bone defects, guided bone regeneration, and treatment of gingival recession. More recently, PCs have been leveraged for tissue regeneration to promote oral soft and hard tissue regeneration in implant dentistry and regenerative periodontology. PCs are ideal for this purpose because they have a high concentration of platelets, growth factors, and cytokines. Platelets have been shown to release extracellular vesicles (P-EVs), which are thought to be essential for PC-induced tissue regeneration. This study reviewed the clinical application of PCs and P-EVs for implant surgery and periodontal tissue regeneration.

Field carcinogenesis and biological significance of the potential of the bystander effect: carcinogenesis, therapeutic response, and tissue regeneration

The "bystander effect" is a transmission phenomenon mediating communication from target to non-target cells, as well as cell-to-cell interactions between neighboring and distantly located cells. In this narrative review, we describe the fundamental and clinical significance of the bystander effect with respect to cell-to-cell interactions in carcinogenesis, therapeutic response, and tissue regeneration. In carcinogenesis, the bystander effect mediates communications between tumor microenvironments and non-malignant epithelial cells and has been suggested to impact heterogeneous tumorigenic cells in tumors and cancerized fields. In therapeutic response, the bystander effect mediates communications between drug-sensitive and drug-resistant cells and may transmit both drug efficacy and resistance. Therefore, control of therapeutic response transmission via the bystander effect might offer a promising future cancer treatment. Finally, in tissue regeneration, circulating cells and stromal cells may differentiate into various cells for the purpose of tissue regeneration under direction of the bystander effect arising from surrounding cells in a defective space. We hope that the findings we present will promote the development of innovative cancer therapies and tissue regeneration methodologies from the viewpoint of cell-to-cell interactions through the bystander effect.

Bioinformatics of Differentially Expressed Genes in Phorbol 12-Myristate 13-Acetate-Induced Megakaryocytic Differentiation of K562 Cells by Microarray Analysis

Megakaryocytes are large hematopoietic cells present in the bone marrow cavity, comprising less than 0.1% of all bone marrow cells. Despite their small number, megakaryocytes play important roles in blood coagulation, inflammatory responses, and platelet production. However, little is known about changes in gene expression during megakaryocyte maturation. Here we identified the genes whose expression was changed during K562 leukemia cell differentiation into megakaryocytes using an Affymetrix GeneChip microarray to determine the multifunctionality of megakaryocytes. K562 cells were differentiated into mature megakaryocytes by treatment for 7 days with phorbol 12-myristate 13-acetate, and a microarray was performed using RNA obtained from both types of cells. The expression of 44,629 genes was compared between K562 cells and mature megakaryocytes, and 954 differentially expressed genes (DEGs) were selected based on a p-value < 0.05 and a fold change >2. The DEGs was further functionally classified using five major megakaryocyte function-associated clusters—inflammatory response, angiogenesis, cell migration, extracellular matrix, and secretion. Furthermore, interaction analysis based on the STRING database was used to generate interactions between the proteins translated from the DEGs. This study provides information on the bioinformatics of the DEGs in mature megakaryocytes after K562 cell differentiation.

Effect of expansion of human umbilical cord blood CD34 + cells on neurotrophic and angiogenic factor expression and function

The use of CD34 + cell-based therapies has largely been focused on haematological conditions. However, there is increasing evidence that umbilical cord blood (UCB) CD34 + -derived cells have neuroregenerative properties. Due to low cell numbers of CD34 + cells present in UCB, expansion is required to produce sufficient cells for therapeutic purposes, especially in adults or when frequent applications are required. However, it is not known whether expansion of CD34 + cells has an impact on their function and neuroregenerative capacity. We addressed this knowledge gap in this study, via expansion of UCB-derived CD34 + cells using combinations of LDL, UM171 and SR-1 to yield large numbers of cells and then tested their functionality. CD34 + cells expanded for 14 days in media containing UM171 and SR-1 resulted in over 1000-fold expansion. The expanded cells showed an up-regulation of the neurotrophic factor genes BDNF, GDNF, NTF-3 and NTF-4, as well as the angiogenic factors VEGF and ANG. In vitro functionality testing showed that these expanded cells promoted angiogenesis and, in brain glial cells, promoted cell proliferation and reduced production of reactive oxygen species (ROS) during oxidative stress. Collectively, this study showed that our 14-day expansion protocol provided a robust expansion that could produce enough cells for therapeutic purposes. These expanded cells, when tested in in vitro, maintained functionality as demonstrated through promotion of cell proliferation, attenuation of ROS production caused by oxidative stress and promotion of angiogenesis.

Coexistence of superficial carcinogenesis of resident epithelium besides neuroendocrine neoplasm of the digestive tract

Background & Aims

Mixed neuroendocrine–non‐neuroendocrine neoplasm (MiNEN) is a rare neuroendocrine neoplasm (NEN) comprising dual neuroendocrine and non‐neuroendocrine components. Although the coexistence pattern of neuroendocrine and non‐neuroendocrine components in definitive MiNEN is thought to overlap, there may be a coexistent pattern of both components, such as superficial carcinoma adjacent to NEN. The present study evaluated the histopathological findings of the coexistence pattern of superficial carcinomas adjacent to NENs in the esophagogastrointestinal tract.

Methods

From 2000 to 2019, 35 serial NEN resections of the esophagus (n = 9), stomach (n = 3), and large intestine (n = 23), respectively, were performed at Gunma University Hospital. Borderline areas between NEN and resident superficial epithelium were observed in the 35 serial NEN cases as well as two additional cases from affiliated hospitals.

Results

Among the 35 serial NEN samples, squamous cell carcinomatous/dysplastic components were identified 77.8% (7/9 cases) of esophageal NENs, and adenocarcinomatous areas were seen in 66.7% (2/3 cases) of gastric NENs and 26% (6/23 cases) of colorectal NENs. Thus, all superficial carcinomatous components adjacent to NENs were observed as squamous cell carcinoma/dysplasia in esophagus and adenocarcinoma in stomach and large intestine, which showed histological characteristics as the resident epithelial pattern in each organ.

Conclusions

These findings suggested a potential “paratransformation” or “bystander effect” in resident epithelium by NENs. Thus, “bystander carcinogenesis” could be a pathogenic mechanism of resident epithelium transformation adjacent to NENs in the esophagogastrointestinal tract.

Insulin-like growth factor-1 and insulin-like growth factor binding protein-3: impact on early haematopoietic reconstitution following allogeneic haematopoietic stem cell transplantation

OBJECTIVES

The aim of the study was to investigate whether high endogenous levels of insulin-like growth factor-1 (IGF-1) and its binding protein-3 (IGFBP-3) were related to a faster reconstitution of different blood cell populations in the early phase after allogeneic myeloablative haematopoietic stem cell transplantation (HSCT).

METHODS

We measured IGF-1 and IGFBP-3 by chemiluminescence during the first three weeks after transplantation in 35 adult patients undergoing myeloablative HSCT and calculated area under the curve divided by time (AUC/t) for each patient.

RESULTS

Circulating levels of IGF-1 and IGFBP-3 correlated with counts of reticulocytes (r_s  = 0.44, p = .011 and r = 0.41, p = .017, respectively) and thrombocytes (r_s  = 0.38, p = .030 and r_s  = 0.56, p = .0008) three weeks post-transplant. Furthermore, high IGFBP-3 levels correlated with absolute lymphocyte counts 3 weeks post-HSCT (r_s  = 0.54, p = .012) and were associated with shorter time to neutrophil engraftment (r_s  = -0.35, p = .043). Both IGF-1 and IGFBP-3 levels were associated with the number of circulating natural killer cells one month after HSCT (r_s  = 0.42, p = .032 and r_s  = 0.57, p = .0026).

CONCLUSION

These data indicate that high levels of IGF-1 and IGFBP-3 relate to a faster haematopoietic reconstitution after HSCT and suggest a biological influence of these mediators in haematopoietic homeostasis in these patients.

Early onset of aging phenotype in vascular repair by Mas receptor deficiency

Aging is associated with impaired vascular repair following ischemic insult, largely due to reparative dysfunctions of progenitor cells. Activation of Mas receptor (MasR) was shown to reverse aging-associated vasoreparative dysfunction. This study tested the impact of MasR-deficiency on mobilization and vasoreparative functions with aging. Wild type (WT) or MasR-deficient mice (MasR^-/- or MasR^+/-) at 12-14 weeks (young) or middle age (11-12 months) (MA) were used in the study. Mobilization of lineage-negative, Sca-1-positive cKit-positive (LSK) cells in response to G-CSF or plerixafor was determined. Hindlimb ischemia (HLI) was induced by femoral artery ligation. Mobilization and blood flow recovery were monitored post-HLI. Radiation chimeras were made by lethal irradiation of WT or MasR^-/- mice followed by administration of bone marrow cells from MasR^-/- or WT mice, respectively. Nitric oxide (NO) generation by stromal-derived factor-1α (SDF) and mitochondrial reactive oxygen species (mitoROS) levels were determined by flow cytometry. Effect of A779 treatment on mobilization, blood flow recovery, and NO and ROS levels were determined in young WT and MasR^+/- mice. Circulating LSK cells in basal or in response to plerixafor or G-CSF or in response to ischemic injury were lower in MasR^-/- mice compared to the WT. Responses in MasR^+/- mice were similar to the WT at young age but at the middle age, impairments were observed. Impaired mobilization to ischemia or G-CSF was rescued in WT → MasR^-/- chimeras. NO levels were lower and mitoROS were higher in MasR^-/- LSK cells compared to WT cells. A779 precipitated dysfunctions in young-MasR^+/- mice similar to that observed in MA-MasR^+/-, and this accompanied decreased NO generation by SDF and enhanced mitoROS levels. This study shows that mice at MA do not exhibit vasoreparative dysfunction. Either partial or total loss of MasR precipitates advanced-aging phenotype likely due to lack of NO and oxidative stress.

Angiogenic CD34 Stem Cell Therapy in Coronary Microvascular Repair-A Systematic Review

Ischemia with non-obstructive coronary arteries (INOCA) is an increasingly recognized disease, with a prevalence of 3 to 4 million individuals, and is associated with a higher risk of morbidity, mortality, and a worse quality of life. Persistent angina in many patients with INOCA is due to coronary microvascular dysfunction (CMD), which can be difficult to diagnose and treat. A coronary flow reserve <2.5 is used to diagnose endothelial-independent CMD. Antianginal treatments are often ineffective in endothelial-independent CMD and thus novel treatment modalities are currently being studied for safety and efficacy. CD34+ cell therapy is a promising treatment option for these patients, as it has been shown to promote vascular repair and enhance angiogenesis in the microvasculature. The resulting restoration of the microcirculation improves myocardial tissue perfusion, resulting in the recovery of coronary microvascular function, as evidenced by an improvement in coronary flow reserve. A pilot study in INOCA patients with endothelial-independent CMD and persistent angina, treated with autologous intracoronary CD34+ stem cells, demonstrated a significant improvement in coronary flow reserve, angina frequency, Canadian Cardiovascular Society class, and quality of life (ESCaPE-CMD, NCT03508609). This work is being further evaluated in the ongoing FREEDOM (NCT04614467) placebo-controlled trial.

Preventing Brain Damage from Hypoxic-Ischemic Encephalopathy in Neonates: Update on Mesenchymal Stromal Cells and Umbilical Cord Blood Cells

Neonatal hypoxic-ischemic encephalopathy (HIE) causes permanent motor deficit "cerebral palsy (CP)," and may result in significant disability and death. Therapeutic hypothermia (TH) had been established as the first effective therapy for neonates with HIE; however, TH must be initiated within the first 6 hours after birth, and the number needed to treat is from 9 to 11 to prevent brain damage from HIE. Therefore, additional therapies for HIE are highly needed. In this review, we provide an introduction on the mechanisms of HIE cascade and how TH and cell therapies such as umbilical cord blood cells and mesenchymal stromal cells (MSCs), especially umbilical cord-derived MSCs (UC-MSCs), may protect the brain in newborns, and discuss recent progress in regenerative therapies using UC-MSCs for neurological disorders.The brain damage process "HIE cascade" was divided into six stages: (1) energy depletion, (2) impairment of microglia, (3) inflammation, (4) excitotoxity, (5) oxidative stress, and (6) apoptosis in capillary, glia, synapse and/or neuron. The authors showed recent 13 clinical trials using UC-MSCs for neurological disorders.The authors suggest that the next step will include reaching a consensus on cell therapies for HIE and establishment of effective protocols for cell therapy for HIE. KEY POINTS: · This study includes new insights about cell therapy for neonatal HIE and CP in schema.. · This study shows precise mechanism of neonatal HIE cascade.. · The mechanism of cell therapy by comparing umbilical cord blood stem cell with MSC is shown.. · The review of recent clinical trials of UC-MSC is shown..

Any closer to successful therapy of multiple myeloma? CAR-T cell is a good reason for optimism

Despite many recent advances on cancer novel therapies, researchers have yet a long way to cure cancer. They have to deal with tough challenges before they can reach success. Nonetheless, it seems that recently developed immunotherapy-based therapy approaches such as adoptive cell transfer (ACT) have emerged as a promising therapeutic strategy against various kinds of tumors even the cancers in the blood (liquid cancers). The hematological (liquid) cancers are hard to be targeted by usual cancer therapies, for they do not form localized solid tumors. Until recently, two types of ACTs have been developed and introduced; tumor-infiltrating lymphocytes (TILs) and chimeric antigen receptor (CAR)-T cells which the latter is the subject of our discussion. It is interesting about engineered CAR-T cells that they are genetically endowed with unique cancer-specific characteristics, so they can use the potency of the host immune system to fight against either solid or liquid cancers. Multiple myeloma (MM) or simply referred to as myeloma is a type of hematological malignancy that affects the plasma cells. The cancerous plasma cells produce immunoglobulins (antibodies) uncontrollably which consequently damage the tissues and organs and break the immune system function. Although the last few years have seen significant progressions in the treatment of MM, still a complete remission remains unconvincing. MM is a medically challenging and stubborn disease with a disappointingly low rate of survival rate. When comparing the three most occurring blood cancers (i.e., lymphoma, leukemia, and myeloma), myeloma has the lowest 5-year survival rate (around 40%). A low survival rate indicates a high mortality rate with difficulty in treatment. Therefore, novel CAR-T cell-based therapies or combination therapies along with CAT-T cells may bring new hope for multiple myeloma patients. CAR-T cell therapy has a high potential to improve the remission success rate in patients with MM. To date, many preclinical and clinical trial studies have been conducted to investigate the ability and capacity of CAR T cells in targeting the antigens on myeloma cells. Despite the problems and obstacles, CAR-T cell experiments in MM patients revealed a robust therapeutic potential. However, several factors might be considered during CAR-T cell therapy for better response and reduced side effects. Also, incorporating the CAT-T cell method into a combinational treatment schedule may be a promising approach. In this paper, with a greater emphasis on CAR-T cell application in the treatment of MM, we will discuss and introduce CAR-T cell's history and functions, their limitations, and the solutions to defeat the limitations and different types of modifications on CAR-T cells.

CD34+ cells and endothelial progenitor cell subpopulations are associated with cerebral small vessel disease burden

Background: Endothelial dysfunction is considered to be involved in the pathogenesis of cerebral small vessel disease (CSVD). Endothelial progenitor cells are associated with endothelial dysfunction. The present study was designed to investigate the correlation between the populations of circulating CD34-positive cells and endothelial progenitor cells and CSVD burden. Methodology & results: A total of 364 patients with confirmed diagnosis of CSVD were included in this prospective study. Multiple ordinal logistic regression analyses showed that subjects with higher CSVD burden had significantly decreased circulating CD34⁺ cell level (odds ratio [OR], 0.42; p = 0.034) and significantly increased levels of circulating CD34⁺CD133⁺CD309⁺ and CD34⁺CD133⁺ cells (OR 1.07, p = 0.031; OR 1.03, p = 0.001, respectively), compared with patients with lower CSVD burden. Conclusion: The findings suggest that the levels of circulating CD34⁺ cells, CD34⁺CD133⁺CD309⁺ cells and CD34⁺CD133⁺ cells may be used as potential biomarkers to monitor the disease progression of CSVD.

Hematopoietic stem and progenitor cell signaling in the niche

Hematopoietic stem and progenitor cells (HSPCs) are responsible for lifelong maintenance of hematopoiesis through self-renewal and differentiation into mature blood cell lineages. Traditional models hold that HSPCs guard homeostatic function and adapt to regenerative demand by integrating cell-autonomous, intrinsic programs with extrinsic cues from the niche. Despite the biologic significance, little is known about the active roles HSPCs partake in reciprocally shaping the function of their microenvironment. Here, we review evidence of signals emerging from HSPCs through secreted autocrine or paracrine factors, including extracellular vesicles, and via direct contact within the niche. We also discuss the functional impact of direct cellular interactions between hematopoietic elements on niche occupancy in the context of leukemic infiltration. The aggregate data support a model whereby HSPCs are active participants in the dynamic adaptation of the stem cell niche unit during development and homeostasis, and under inflammatory stress, malignancy, or transplantation.

Relationships of handgrip strength with the presence of cerebral microbleeds and platelet count in older Japanese adults

Introduction: Lower handgrip strength is a manifestation of sarcopenia and frailty, and has been reported to be associated with cerebral microbleeds (CMBs), which appear on T2^*-weighted magnetic resonance scans as low-intensity spots. However, the underlying mechanism is unknown. We hypothesized that vascular endothelial injury could be the common factor in loss of handgrip strength and CMBs. We aimed to clarify the relationship between handgrip strength and CMBs, with reference to a marker of vascular repair capability.

Materials and Methods: We conducted a cross-sectional study of 95 60- to 87-year-old Japanese people who underwent brain magnetic resonance imaging in 2016–2017. Baseline information was obtained by trained interviewers regarding the age, sex, smoking status, nutrient intake, cognition, medical history, education, and household income of the participants. Physical activity was assessed using a tri-axial accelerometer. We used the Fried frailty phenotype definition. Multivariable linear regression analysis was performed.

Results: Handgrip strength was independently associated with the presence of CMB after adjustment for age, sex, body mass index, classical cardiovascular risk factors, protein intake, and daily activity (B = −3.43, p = 0.027). This association was shown in participants with a low (B = −4.05, p = 0.045) but not high platelet count (B=−2.23, p = 0.479). Frailty was also independently associated with the presence of CMB after adjustment for confounders (B = 0.57, p = 0.014). Although this association was not present in participants a high platelet count, there was a positive trend in those with a low platelet count (B = 0.50, p = 0.135).

Conclusions: Platelet count, a marker of vascular repair capability, appears to modify the relationship between handgrip strength and CMBs.

Targeting Angiotensin-Converting Enzyme-2/Angiotensin-(1-7)/Mas Receptor Axis in the Vascular Progenitor Cells for Cardiovascular Diseases

Bone marrow-derived hematopoietic stem/progenitor cells are vasculogenic and play an important role in endothelial health and vascular homeostasis by participating in postnatal vasculogenesis. Progenitor cells are mobilized from bone marrow niches in response to remote ischemic injury and migrate to the areas of damage and stimulate revascularization largely by paracrine activation of angiogenic functions in the peri-ischemic vasculature. This innate vasoprotective mechanism is impaired in certain chronic clinical conditions, which leads to the development of cardiovascular complications. Members of the renin-angiotensin system-angiotensin-converting enzymes (ACEs) ACE and ACE2, angiotensin II (Ang II), Ang-(1-7), and receptors AT1 and Mas-are expressed in vasculogenic progenitor cells derived from humans and rodents. Ang-(1-7), generated by ACE2, is known to produce cardiovascular protective effects by acting on Mas receptor and is considered as a counter-regulatory mechanism to the detrimental effects of Ang II. Evidence has now been accumulating in support of the activation of the ACE2/Ang-(1-7)/Mas receptor pathway by pharmacologic or molecular maneuvers, which stimulates mobilization of progenitor cells from bone marrow, migration to areas of vascular damage, and revascularization of ischemic areas in pathologic conditions. This minireview summarizes recent studies that have enhanced our understanding of the physiology and pharmacology of vasoprotective axis in bone marrow-derived progenitor cells in health and disease. SIGNIFICANCE STATEMENT: Hematopoietic stem progenitor cells (HSPCs) stimulate revascularization of ischemic areas. However, the reparative potential is diminished in certain chronic clinical conditions, leading to the development of cardiovascular diseases. ACE2 and Mas receptor are key members of the alternative axis of the renin-angiotensin system and are expressed in HSPCs. Accumulating evidence points to activation of ACE2 or Mas receptor as a promising approach for restoring the reparative potential, thereby preventing the development of ischemic vascular diseases.

Total degradation of extracellular amyloids by miniature artificial proteases

A miniaturized mimic of the active site of a protease, chymotrypsin, was linked to a target recognition unit to generate "Miniature Artificial Proteases" (mAPs). Time-resolved MALDI-TOF data analyses indicated that mAPs cleaved every amide bond between Lys16-Phe20 of the amyloid β fragment (Aβ12-21) and Aβ1-40, resulting in inhibition of fibrillization and disruption of the preformed amyloid. Such a platform may offer not only new therapeutic options against various amyloidoses but also novel routes for the selective knockdown of specific proteins.

Cancer exosomal microRNAs from gefitinib-resistant lung cancer cells cause therapeutic resistance in gefitinib-sensitive cells

PURPOSE

Exosomes and their cargo microRNAs play a significant role in various biological processes in cancer. We hypothesized that microRNAs in exosomes secreted by gefitinib-resistant lung cancer cells might induce resistant phenotypes in otherwise gefitinib-sensitive lung cancer cells.

METHODS

We isolated exosomes generated by the gefitinib-resistant human lung adenocarcinoma cell line PS-9/ZD. PC-9, which is a gefitinib-sensitive cell line, was treated with the PC-9/ZD exosomes, and these PC-9 cells were analyzed for cell proliferation after treatment with gefitinib. miRNA arrays were analyzed in PC-9 and PC-9/ZD cells, and we isolated microRNAs that were expressed at elevated levels in PC-9/ZD cells. Furthermore, we transfected these microRNAs into PC-9 cells and analyzed the effects on the cells' sensitivity to gefitinib.

RESULTS

Exosomes isolated from PC-9/ZD cells significantly increased the proliferation of PC-9 cells during gefitinib treatment. A microRNA array analysis showed that miR-564, miR-658, miR-3652, miR-3126-5p, miR-3682-3p and miR-6810-5p were significantly upregulated in PC-9/ZD cells. PC-9 cells transfected with miR-564 or miR-658 showed chemo-resistant phenotypes.

CONCLUSION

Exosomal miR-564 and miR-658 derived from gefitinib-resistant lung cancer cells induce drug resistance in sensitive cells. Cell-to-cell interaction via exosomal microRNAs may be a novel mechanism and therapeutic target of resistance against gefitinib.

The Effect of Intracoronary Infusion of Autologous Bone Marrow-Derived Lineage-Negative Stem/Progenitor Cells on Remodeling of Post-Infarcted Heart in Patient with Acute Myocardial Infarction

Introduction: Regenerative capacity of the heart is limited, and the post-infarct left ventricle (LV) dysfunction is associated with poor prognosis. Administration of stem/progenitor cells (SPCs) is a promising approach for cardiac regeneration. Objectives: In the study, we assessed LV function and post-infarcted remodeling in patients with ST-elevated myocardial infarct (STEMI) who received autologous lineage-negative (LIN^-) SPCs. Patients and methods: Patients with STEMI and one-vessel coronary artery disease treated with percutaneous revascularisation were divided into study group (LIN^- group, 15 patients) that received standard therapy and autologous BM-derived LIN^- SPCs and control group (standard therapy group, 19 patients). The cells were administered intracoronary 24 hours after STEMI. The follow-up was 12 months with subsequent non-invasive tests and laboratory parameter evaluation on days 1^st, 3^rd, and 7^th as well as at 1^st, 3^rd, 6^th and 12^th month after STEMI. Results: All procedures related to SPCs administration were well tolerated by the patients. In 12-month follow-up, there were no major adverse cardiac events connected with LIN^- SPCs administration. During 12-month follow-up, 9 patients from LIN^- group (Responders) achieved an improvement in LV ejection fraction (>10% after 12 months) with no signs of unfavorable LV remodeling. Laboratory parameters analysis showed that Troponin T levels were significantly lower until day 7^th in the Responders group, while brain natriuretic peptide (BNP) level remained significantly lower from day 3^rd to 12^th month respectively. Conclusions: Intracoronary infusion of autologous BM-derived LIN^- stem/progenitor cells is feasible and safe for patient. Improvement in LV function and prevention of unfavorable remodeling in the 60% of study group seems relatively promising. Stem cell-based therapy for cardiac regeneration still needs more accurate and extensive investigations to estimate and improve their efficacy.

Traditional and Advanced Cell Cultures in Hematopoietic Stem Cell Studies

Hematopoiesis is the main function of bone marrow. Human hematopoietic stem and progenitor cells reside in the bone marrow microenvironment, making it a hotspot for the development of hematopoietic diseases. Numerous alterations that correspond to disease progression have been identified in the bone marrow stem cell niche. Complex interactions between the bone marrow microenvironment and hematopoietic stem cells determine the balance between the proliferation, differentiation and homeostasis of the stem cell compartment. Changes in this tightly regulated network can provoke malignant transformation. However, our understanding of human hematopoiesis and the associated niche biology remains limited due to accessibility to human material and the limits of in vitro culture models. Traditional culture systems for human hematopoietic studies lack microenvironment niches, spatial marrow gradients, and dense cellularity, rendering them incapable of effectively translating marrow physiology ex vivo. This review will discuss the importance of 2D and 3D culture as a physiologically relevant system for understanding normal and abnormal hematopoiesis.

The Role of Platelet Concentrates in Facial Fat Grafting

Autologous fat grafting is increasingly being used as a method for the repair of facial soft tissue defects and facial rejuvenation, given its low risk of adverse effects and high efficacy. However, the unpredictability of graft retention is a limitation of this procedure. In addition, there is no standard procedure to date for autologous fat grafting. Different methods have been developed to increase the retention of grafted fat. For instance, platelet concentrates have been used to directly deliver bioactive factors to grafted fat. Platelet concentrates also provide incidental therapeutic benefits by enhancing the persistence of fat grafted in the face via the release of growth factors and cytokines. In this review, we describe current strategies for improving the survival of facial fat grafts, mainly focusing on the application of growth factors/cytokines and platelet concentrates to fat grafting.

The Present and Future of Novel Protein Degradation Technology

Proteolysis targeting chimeras (PROTACs), as a novel therapeutic modality, play a vital role in drug discovery. Each PROTAC contains three key parts; a protein-of-interest (POI) ligand, a E3 ligase ligand, and a linker. These bifunctional molecules could mediate the degradation of POIs by hijacking the activity of E3 ubiquitin ligases for POI ubiquitination and subsequent degradation via the ubiquitin proteasome system (UPS). With several advantages over other therapeutic strategies, PROTACs have set off a new upsurge of drug discovery in recent years. ENDTAC, as the development of PROTACs technology, is now receiving more attention. In this review, we aim to summarize the rapid progress from 2018 to 2019 in protein degradation and analyze the challenges and future direction that need to be addressed in order to efficiently develop potent protein degradation technology.

The promise of chimeric antigen receptor (CAR) T cell therapy in multiple myeloma

A cure for multiple myeloma (MM), a malignancy of plasma cells, remains elusive. Nearly all myeloma patients will eventually relapse and develop resistance to currently available treatments. There is an unmet medical need to develop novel and effective therapies that can induce sustained responses. Early phase clinical trials using chimeric antigen receptor (CAR) T cell therapy have shown great promise in the treatment of relapsed and/or refractory MM. In this review article, we provide an overview of the CAR constructs, the gene transfer vector systems, and approaches for T cell activation and expansion. We then summarize the outcomes of several early phase clinical trials of CAR T cell therapy in MM and the novel CAR T targets that are under development. Finally, we explore the potential mechanisms that result in disease relapse after CAR T therapy and propose future directions in CAR T therapy in MM.

Association between insulin resistance and haematological parameters: A cohort study from adolescence to adulthood

BACKGROUND

The aim of this study was to quantify the relationship between insulin resistance and haematological parameters from adolescence to adulthood.

METHODS

Participants from the EPITeen cohort were evaluated at 13, 17, and 21 years, through standardized procedures. A fasting blood sample was obtained, and insulin resistance was evaluated by the homeostatic model assessment (HOMA-IR). The cross-sectional association between HOMA-IR and haematological parameters at 21 years was quantified in 1671 participants by multivariate linear regression coefficients (β) and 95% confidence intervals (95%CI). For the longitudinal analysis (n = 496), trajectories of insulin and glucose were estimated using model-based clustering, and haematological parameters were compared according to trajectories using ANOVA.

RESULTS

At 21 years, after adjustment for BMI, positive associations (β [95%CI]) were found between HOMA-IR and red blood count (0.05 [0.03;0.07] in females; 0.02 [0.00;0.04] in males); and haematocrit (0.29 [0.12;0.46] in females; 0.21 [0.04,0.38] in males). In females, HOMA-IR was inversely associated with packed cell volume (PCV) (-0.35 [-0.66;-0.05]) and iron levels (-3.98 [-6.94,-1.03]) but positively associated with white blood cells (0.31 [0.19;0.43]) and platelets (7.66 [3.93;11.39]). In males, a higher HOMA-IR was significantly associated with higher haemoglobin (0.09 [0.03;0.16]). Regarding the longitudinal analysis, similar trends were found, but statistical significance was not reached.

CONCLUSIONS

Both longitudinal and cross-sectional analyses support the hypothesis that insulin resistance is associated with increased red blood cells count and haematocrit in young adults, even within normal ranges of insulin and glucose.

Soluble Signals and Remodeling in a Synthetic Gelatin-Based Hematopoietic Stem Cell Niche

Hematopoietic stem cells (HSCs) reside in the bone marrow within niches that provide microenvironmental signals in the form of biophysical cues, bound and diffusible biomolecules, and heterotypic cell-cell interactions that influence HSC fate decisions. This study seeks to inform the development of a synthetic culture platform that promotes ex vivo HSC expansion without exhaustion. A library of methacrylamide-functionalized gelatin (GelMA) hydrogels is used to explore remodeling and crosstalk from mesenchymal stromal cells (MSCs) on the expansion and quiescence of murine HSCs. The use of a degradable GelMA hydrogel enables MSC-mediated remodeling, yielding dynamic shifts in the matrix environment over time. An initially low-diffusivity hydrogel for co-culture of hematopoietic stem and progenitor cells to MSCs facilitates maintenance of an early progenitor cell population over 7 days. Excitingly, this platform promotes retention of a quiescent HSC population compared to HSC monocultures. These studies reveal MSC-density-dependent upregulation of MMP-9 and changes in hydrogel mechanical properties (ΔE = 2.61 ± 0.72) suggesting MSC-mediated matrix remodeling may contribute to a dynamic culture environment. Herein, a 3D hydrogel is reported for ex vivo HSC culture, in which HSC expansion and quiescence is sensitive to hydrogel properties, MSC co-culture, and MSC-mediated hydrogel remodeling.

Novel Evidence of the Increase in Angiogenic Factor Plasma Levels after Lineage-Negative Stem/Progenitor Cell Intracoronary Infusion in Patients with Acute Myocardial Infarction

Cell therapy raises hope to reduce the harmful effects of acute myocardial ischemia. Stem and progenitor cells (SPCs) may be a valuable source of trophic factors. In this study, we assessed the plasma levels of selected trophic factors in patients undergoing application of autologous bone marrow (BM)-derived, lineage-negative (Lin^-) stem/progenitor cells into the coronary artery in the acute phase of myocardial infarction. The study group consisted of 15 patients with acute myocardial infarction (AMI) who underwent percutaneous revascularization and, afterwards, Lin^- stem/progenitor cell administration into the infarct-related artery. The control group consisted of 19 patients. BM Lin^- cells were isolated using immunomagnetic methods. Peripheral blood was collected on day 0, 2, 4, and 7 and after the first and third month to assess the concentration of selected trophic factors using multiplex fluorescent bead-based immunoassays. We found in the Lin^- group that several angiogenic trophic factors (vascular endothelial growth factor, Angiopoietin-1, basic fibroblast growth factor, platelet-derived growth factor-aa) plasma level significantly increased to the 4th day after myocardial infarction. In parallel, we noticed a tendency where the plasma levels of the brain-derived neurotrophic factor were increased in the Lin^- group. The obtained results suggest that the administered SPCs may be a valuable source of angiogenic trophic factors for damaged myocardium, although this observation requires further in-depth studies.

Targeted Protein Internalization and Degradation by ENDosome TArgeting Chimeras (ENDTACs)

Targeted protein degradation has generated excitement in chemical biology and drug discovery throughout academia and industry. By hijacking the machinery responsible for protein degradation via the ubiquitin proteasome system (UPS), various cellular targets have been selectively degraded. However, since the tools used, often termed PROteolysis TArgeting Chimeras (PROTACs), hijack the intracellular quality control machinery, this technology can only access targets within the cell. Extracellular targets such as growth factors, cytokines, and chemokines bind to cell surface receptors, often initiating aberrant signaling in multiple diseases such as cancer and inflammation. However, efforts to develop small molecule inhibitors for these extracellular target proteins have been challenging. Herein, we developed a proof-of-concept approach to evaluate if extracellular proteins can be internalized and degraded via the receptor-mediated endolysosomal pathway. Using a heterodimeric molecule, termed "ENDosome TArgeting Chimera" (ENDTAC), internalization and degradation of an extracellular recombinant eGFP-HT7 fusion protein was achieved by hijacking the decoy GPCR receptor, CXCR7. This proof-of-concept study suggests that using ENDTACs to co-opt the endosomal-lysosomal degradation pathway, in contrast to PROTACs using the UPS, may provide an avenue for degrading extracellular targets such as cytokines. Overall, the technology described herein provides a novel expansion to the field of targeted protein degradation.

CD34+ Stem Cells: Promising Roles in Cardiac Repair and Regeneration

Cell therapy has received significant attention as a novel therapeutic approach to restore cardiac function after injury. CD34-positive (CD34⁺) stem cells have been investigated for their ability to promote angiogenesis and contribute to the prevention of remodelling after infarct. However, there are significant differences between murine and human CD34⁺ cells; understanding these differences might benefit the therapeutic use of these cells. Herein we discuss the function of the CD34 cell and highlight the similarities and differences between murine and human CD34 cell function, which might explain some of the differences between the animal and human evolutions. We also summarize the studies that report the application of murine and human CD34⁺ cells in preclinical studies and clinical trials and current limitations with the application of cell therapy for cardiac repair. Finally, to overcome these limitations we discuss the application of novel humanized rodent models that can bridge the gap between preclinical and clinical studies as well as rejuvenation strategies for improving the quality of old CD34⁺ cells for future clinical trials of autologous cell transplantation.

High-intensity interval training followed by postexercise cold-water immersion does not alter angiogenic circulating cells, but increases circulating endothelial cells

High-intensity interval training (HIIT) induces vascular adaptations that might be attenuated by postexercise cold-water immersion (CWI). Circulating angiogenic cells (CAC) participate in the vascular adaptations and circulating endothelial cells (CEC) indicate endothelial damage. CAC and CEC are involved in vascular adaptation. Therefore, the aim of the study was to investigate postexercise CWI during HIIT on CAC and CEC and on muscle angiogenesis-related molecules. Seventeen male subjects performed 13 HIIT sessions followed by 15 min of passive recovery (n = 9) or CWI at 10 °C (n = 8). HIIT comprised cycling (8-12 bouts, 90%-110% peak power). The first and the thirteenth sessions were similar (8 bouts at 90% of peak power). Venous blood was drawn before exercise (baseline) and after the recovery strategy (postrecovery) in the first (pretraining) and in the thirteenth (post-training) sessions. For CAC and CEC identification lymphocyte surface markers (CD133, CD34, and VEGFR2) were used. Vastus lateralis muscle biopsies were performed pre- and post-training for protein (p-eNOS^ser1177) and gene (VEGF and HIF-1) expression analysis related to angiogenesis. CAC was not affected by HIIT or postexercise CWI. Postexercise CWI increased acute and baseline CEC number. Angiogenic protein and genes were not differently modulated by post-CWI. HIIT followed by either recovery strategy did not alter CAC number. Postexercise CWI increased a marker of endothelial damage both acutely and chronically, suggesting that this postexercise recovery strategy might cause endothelial damage. Novelty HIIT followed by CWI did not alter CAC. HIIT followed by CWI increased CEC. Postexercise CWI might cause endothelial damage.

Cardio-ankle vascular index and circulating CD34-positive cell levels as indicators of endothelial repair activity in older Japanese men

AIM

The cardio-ankle vascular index (CAVI) reflects functional arterial stiffness, which is related to endothelial dysfunction. CD34-positive cells carry out an important function in endothelial repair. However, there have been no reports assessing the association between CAVI and the number of circulating CD34-positive cells.

METHODS

We carried out a cross-sectional study of 249 Japanese men, aged 60-69 years, who underwent annual health checkups between 2013 and 2015. As individuals with high levels of circulating CD34-positive cells might indicate the influence of consumptive reduction of circulating CD34-positive cells as a result of aggressive endothelial repair, participants were stratified by circulating CD34-positive cell levels, using the median value in this population (0.95 cells/μL) as the cut-off.

RESULTS

For participants with low circulating CD34-positive cell levels, logarithmic values of circulating CD34-positive cells were inversely associated with CAVI (multivariable standardized parameter estimate [β] = -0.22, P = 0.014), but not for participants with high levels (β = -0.04, P = 0.638). In addition, even when no significant associations between CAVI and carotid intima-media thickness were detected for participants with low circulating CD34-positive cell levels (β = -0.02, P = 0.865), significant positive associations were identified for participants with high levels (β = 0.22, P = 0.028).

CONCLUSIONS

As circulating CD34-positive cell count might indicate endothelial repair activity, the present results show that CAVI is affected by insufficient endothelial repair in individuals with low circulating CD34-positive cell counts. Our results also show that a positive association between CAVI and carotid intima-media thickness exists only in individuals with aggressive endothelial repair, which indicates the presence of organic arterial disease, such as atherosclerosis. Geriatr Gerontol Int 2019; 19: 557-562.

Exercise and Cardiovascular Progenitor Cells

Autologous stem/progenitor cell-based methods to restore blood flow and function to ischemic tissues are clinically appealing for the substantial proportion of the population with cardiovascular diseases. Early preclinical and case studies established the therapeutic potential of autologous cell therapies for neovascularization in ischemic tissues. However, trials over the past ∼15 years reveal the benefits of such therapies to be much smaller than originally estimated and a definitive clinical benefit is yet to be established. Recently, there has been an emphasis on improving the number and function of cells [herein generally referred to as circulating angiogenic cells (CACs)] used for autologous cell therapies. CACs include of several subsets of circulating cells, including endothelial progenitor cells, with proangiogenic potential that is largely exerted through paracrine functions. As exercise is known to improve CV outcomes such as angiogenesis and endothelial function, much attention is being given to exercise to improve the number and function of CACs. Accordingly, there is a growing body of evidence that acute, short-term, and chronic exercise have beneficial effects on the number and function of different subsets of CACs. In particular, recent studies show that aerobic exercise training can increase the number of CACs in circulation and enhance the function of isolated CACs as assessed in ex vivo assays. This review summarizes the roles of different subsets of CACs and the effects of acute and chronic exercise on CAC number and function, with a focus on the number and paracrine function of circulating CD34+ cells, CD31+ cells, and CD62E+ cells. © 2019 American Physiological Society. Compr Physiol 9:767-797, 2019.

Enabling Large-Scale Ex Vivo Production of Megakaryocytes from CD34+ Cells Using Gas-Permeable Surfaces

Patients suffering from acute or sustained thrombocytopenia require platelet transfusions, which are entirely donor-based and limited by challenges related to storage and fluctuating supply. Developing cell-culture technologies will enable ex vivo and donor-independent platelet production. However, critical advancements are needed to improve scalability and increase megakaryocyte (Mk) culture productivity. To address these needs, we evaluated Mk production from mobilized peripheral blood CD34⁺ cells cultured on a commercially available gas-permeable silicone rubber membrane, which provides efficient gas exchange, and investigated the use of fed-batch media dilution schemes. Starting with a cell-surface density of 40 × 10³ CD34⁺ cells per cm² (G40D), culturing cells on the membrane for the first 5 days and employing media dilutions yielded 39 ± 19 CD41⁺ CD42b⁺ Mks per input CD34⁺ cell by day 11-a 2.2-fold increase compared with using standard culture surfaces and full media exchanges. By day 7, G40D conditions generated 1.5-fold more CD34⁺ cells and nearly doubled the numbers of Mk progenitors. The increased number of Mk progenitors coupled with media dilutions, potentially due to the retention of interleukin (IL)-3, increased Mk production in G40D. Compared with controls, G40D had higher viability, yielded threefold more Mks per milliliter of media used and exhibited lower mean ploidy, but had higher numbers of high-ploidy Mks. Finally, G40D-Mks produced proplatelets and platelet-like-particles that activate and aggregate upon stimulation. These results highlight distinct improvements in Mk cell-culture and demonstrate how new technologies and techniques are needed to enable clinically relevant production of Mks for platelet generation and cell-based therapies.

Mobilization of Stem and Progenitor Cells in Septic Shock Patients

Septic shock is associated with multiple injuries to organs and tissues. These events may induce the regenerative response of adult stem cells. However, little is known about how endogenous stem cells are modulated by sepsis. This study analyzed the circulation of hematopoietic stem cells (HSCs), endothelial progenitor cells (EPCs) and very small embryonic-like stem cells (VSELs) in the peripheral blood of patients with septic shock. Thirty-three patients with septic shock and twenty-two healthy control subjects were enrolled in this prospective observational study. Blood samples were collected on the first, third and seventh days of septic shock. Populations of stem cells were analyzed by flow cytometry. Chemotactic mediators were analyzed by HPLC and ELISA. Populations of early HSCs (Lin-CD133+CD45+ and CD34+CD38−) were mobilized to the peripheral blood after an initial decrease. Mobilized HSCs showed significantly increased expression of Ki-67, a marker of cell proliferation. Circulating EPCs and VSELs were mobilized to the blood circulation upon the first day of sepsis. Patients with a greater number of Lin-CD133+CD45+ HSCs and Lin-CD34+CD45− VSELs had a significantly lower probability of 60-day survival. The concentration of CXCL12 was elevated in the blood of septic patients, while the concentration of sphingosine-1-phosphate was significantly decreased. As an emergency early response to sepsis, VSELs and EPCs were mobilized to the peripheral blood, while the HSCs showed delayed mobilization. Differential mobilization of stem cell subsets reflected changes in the concentration of chemoattractants in the blood. The relationship between the probability of death and a large number of HSCs and VSELs in septic shock patients can be used as a novel prognostic marker and may provide new therapeutic approaches.

Tumor-derived exosomes: Potential biomarkers and therapeutic target in the treatment of colorectal cancer

Colorectal cancer (CRC) is the third most common cause of cancer-related death in men and women in many countries. Early detection of CRC helps to prevent the advanced stages of the disease, and may thereby improve the survival of these patients. A noninvasive test with high specificity and sensitivity is required for this. Exosomes are lipid bilayer membrane nanovesicles that are released into most body fluids and especially in the microenvironment of cancer. They carry various proteins, lipids, and nucleic materials such as DNA, RNA, messenger RNA (mRNA), and microRNA (miRNA), and may also alter the function of target cells. In this review, we aimed to describe the biogenesis, composition, function, and the role of tumor-derived exosomes in cancer progression. Moreover, their applications in tumor diagnosis and treatment are described, with a particular focus on CRC.

Native-mimicking in vitro microenvironment: an elusive and seductive future for tumor modeling and tissue engineering

Human connective tissues are complex physiological microenvironments favorable for optimal survival, function, growth, proliferation, differentiation, migration, and death of tissue cells. Mimicking native tissue microenvironment using various three-dimensional (3D) tissue culture systems in vitro has been explored for decades, with great advances being achieved recently at material, design and application levels. These achievements are based on improved understandings about the functionalities of various tissue cells, the biocompatibility and biodegradability of scaffolding materials, the biologically functional factors within native tissues, and the pathophysiological conditions of native tissue microenvironments. Here we discuss these continuously evolving physical aspects of tissue microenvironment important for human disease modeling, with a focus on tumors, as well as for tissue repair and regeneration. The combined information about human tissue spaces reflects the necessities of considerations when configuring spatial microenvironments in vitro with native fidelity to culture cells and regenerate tissues that are beyond the formats of 2D and 3D cultures. It is important to associate tissue-specific cells with specific tissues and microenvironments therein for a better understanding of human biology and disease conditions and for the development of novel approaches to treat human diseases.