Prolonged Growth Hormone/Insulin/Insulin-like Growth Factor Nutrient Response Signaling Pathway as a Silent Killer of Stem Cells and a Culprit in Aging

Anthocyanins-natural pigment of colored rice bran: Composition and biological activities

Rice by-products are a potential source of various bioactive substances with great processing potential, which are receiving increasing attention. Among them, rice bran is a by-product of rice milling, with high nutritional value and health benefits. Colored rice bran contains a large amount of anthocyanins responsible for color and bioactivities. And anthocyanins are often added to foods as a natural pigment, serving to enhance both the visual appeal and nutritional value. Recent advances in the composition and bioactivities of four common colored rice bran anthocyanins (black, purple, red, and purple red rice) are reviewed in this paper. Rice bran anthocyanins have been confirmed to exhibit biological potential for human health, with their main biological activities being antioxidant, anti-atherosclerosis, anti-cancer, neuroprotective, retinoprotective, immunomodulatory, anti-aging and anti-obesity effects. The structure of anthocyanins determines their biological activities. The anthocyanins composition of rice bran with different colors varied greatly, while that of rice bran with the same color is also slightly different, which is attributed to the rice varieties, growing environment and cropping conditions. However, it remains necessary to conduct further clinical studies to support the health activities of anthocyanins. The present review provides information value for the further development and comprehensive utilization of rice bran anthocyanins.

Alterations in Stem Cell Populations in IGF-1 Deficient Pediatric Patients Subjected to Mecasermin (Increlex) Treatment

Pathway involving insulin-like growth factor 1 (IGF-1) plays significant role in growth and development. Crucial role of IGF-1 was discovered inter alia through studies involving deficient patients with short stature, including Laron syndrome individuals. Noteworthy, despite disturbances in proper growth, elevated values for selected stem cell populations were found in IGF-1 deficient patients. Therefore, here we focused on investigating role of these cells-very small embryonic-like (VSEL) and hematopoietic stem cells (HSC), in the pathology. For the first time we performed long-term observation of these populations in response to rhIGF-1 (mecasermin) therapy. Enrolled pediatric subjects with IGF-1 deficiency syndrome were monitored for 4-5 years of rhIGF-1 treatment. Selected stem cells were analyzed in peripheral blood flow cytometrically, together with chemoattractant SDF-1 using immunoenzymatic method. Patients' data were collected for correlation of experimental results with clinical outcome. IGF-1 deficient patients were found to demonstrate initially higher levels of VSEL and HSC compared to healthy controls, with their gradual decrease in response to therapy. These changes were significantly associated with SDF-1 plasma levels. Correlations of VSEL and HSC were also reported in reference to growth-related parameters, and IGF-1 and IGFBP3 values. Noteworthy, rhIGF-1 was shown to efficiently induce development of Laron patients achieving at least proper rate of growth (compared to healthy group) in 80% of subjects. In conclusion, here we provided novel insight into stem cells participation in IGF-1 deficiency in patients. Thus, we demonstrated basis for future studies in context of stem cells and IGF-1 role in growth disturbances.

Very small embryonic-like stem cells have the potential to win the three-front war on tissue damage, cancer, and aging

The concept of dedifferentiation and reprogramming of mature somatic cells holds much promise for the three-front "war" against tissue damage, cancer, and aging. It was hoped that reprogramming human somatic cells into the induced pluripotent state, along with the use of embryonic stem cells, would transform regenerative medicine. However, despite global efforts, clinical applications remain a distant dream, due to associated factors such as genomic instability, tumorigenicity, immunogenicity, and heterogeneity. Meanwhile, the expression of embryonic (pluripotent) markers in multiple cancers has baffled the scientific community, and it has been suggested that somatic cells dedifferentiate and "reprogram" into the pluripotent state in vivo to initiate cancer. It has also been suggested that aging can be reversed by partial reprogramming in vivo. However, better methods are needed; using vectors or Yamanaka factors in vivo, for example, is dangerous, and many potential anti-aging therapies carry the same risks as those using induced pluripotent cells, as described above. The present perspective examines the potential of endogenous, pluripotent very small embryonic-like stem cells (VSELs). These cells are naturally present in multiple tissues; they routinely replace diseased tissue and ensure regeneration to maintain life-long homeostasis, and they have the ability to differentiate into adult counterparts. Recent evidence suggests that cancers initiate due to the selective expansion of epigenetically altered VSELs and their blocked differentiation. Furthermore, VSEL numbers have been directly linked to lifespan in studies of long- and short-lived transgenic mice, and VSEL dysfunction has been found in the ovaries of aged mice. To conclude, a greater interest in VSELs, with their potential to address all three fronts of this war, could be the "light at the end of the tunnel."

Isolation of Swine Bone Marrow Lin-/CD45-/CD133 + Cells and Cardio-protective Effects of its Exosomes

BACKGROUND

The identification in murine bone marrow (BM) of CD133 + /Lin-/CD45- cells, possessing several features of pluripotent stem cells, encouraged us to investigate if similar population of cells could be also isolated from the swine BM. Heart failure is the terminal stage of many cardiovascular diseases, and its key pathological basis is cardiac fibrosis (CF). Research showed that stem cell derived exosomes may play a critical role in cardiac fibrosis. The effect of exosomes (Exos) on CF has remained unclear.

OBJECTIVE

To establish an isolation and amplification method of CD133 + /Lin-/CD45- cells from newbron swine BM in vitro, explore an highly efficient method to enrich swine bone marrow derived CD133 + /Lin-/CD45- cells and probe into their biological characteristics further. Furher more, to extract exosomes from it and explore its effect on CF.

METHODS

The mononuclear cells isolated from swine bone marrow by red blood cell (RBC) lysing buffer were coated by adding FcR blocking solution and coupled with CD133 antibody immunomagnetic beads, obtaining CD133 + cell group via Magnetic Activated Cell Sorting (MACS). In steps, the CD133 + /Lin-/CD45- cells were collected by fluorescence-activated cell sorting (FACS) labeled with CD133, Lin and CD45 antibodies, which were cultured and amplified in vitro. The biological features of CD133 + /Lin-/CD45- cells were studied in different aspects, including morphological trait observed with inverted microscope, ultrastructural characteristics observed under transmission electron microscope, expression of pluripotent markersidentified by immunofluorescent staining and Alkaline phosphatase staining. The Exos were extracted using a sequential centrifugation approach and its effects on CF were analyzed in Angiotensin II (Ang-II) induced-cardiac fibrosis in vivo. Rats in each group were treated for 4 weeks, and 2D echocardiography was adopted to evaluate the heart function. The degree of cardiac fibrosis was assessed by Hematoxylin-Eosin (HE) and Masson's trichrome staining.

RESULTS

The CD133 + /Lin-/CD45- cells accounted for about 0.2%-0.5% of the total mononuclear cells isolated from swine bone marrow. The combination of MACS and FACS to extract CD133 + /Lin-/CD45- cells could improved efficiency and reduced cell apoptosis. The CD133 + /Lin-/CD45- cells featured typical traits of pluripotent stem cells, the nucleus is large, mainly composed of euchromatin, with less cytoplasm and larger nucleoplasmic ratio, which expressed pluripotent markers (SSEA-1, Oct-4, Nanog and Sox-2) and alkaline phosphatase staining was positive.Animal experiment indicated that the cardiac injury related indexes (BNP、cTnI、CK-MB and TNF-α), the expression of key gene Smad3 and the degree of cardiac fibrosis in Exo treatment group were significantly reduced compared with the control group. 4 weeks after the treatment, cardiac ejection fraction (EF) value in the model group showed a remarkable decrease, indicating the induction of HF model. While Exo elevated the EF values, demonstrating cardio-protective effects.

CONCLUSION

The CD133 + /Lin-/CD45- cells derived from swine bone marrow were successfully isolated and amplified, laying a good foundation for further research on this promising therapeutic cell. The Exos may be a promising potential treatment strategy for CF.

Histone demethylase KDM5B catalyzed H3K4me3 demethylation to promote differentiation of bone marrow mesenchymal stem cells into cardiomyocytes

Background

Studies have shown that histone H3 methylation is involved in regulating the differentiation of Bone Marrow Mesenchymal Stem Cells (BMSCs). KDM5B can specifically reduce the level of histone 3 lysine 4 trimethylation (H3K4me3), thereby activating the expression of related genes and participating in biological processes such as cell differentiation, embryonic development and tumor formation. Whether KDM5B is involved in the regulation of BMSCs differentiation into cardiomyocytes through the above manner has not been reported.

Objective

To investigate the effect of KDM5B on the induction and differentiation of swine BMSCs into myocardial cells in vitro.

Methods

Swine bone marrow BMSCs were isolated and cultured, and the overexpression, interference expression and blank vector of KMD5B were constructed and transfected by lentivirus. BMSCs was induced to differentiate into cardiomyocytes by 5-azacytidine (5-AZA) in vitro, and the differentiation efficiency was compared by immunofluorescence, RT-PCR, Western Blot and whole-cell patch clamp detection.

Result

Compared with the control group, the expression levels of histone H3K4me3 and pluripotency gene Nanog in KDM5B overexpression group were significantly decreased, while the expression level of key myocardial gene HCN4 and myocardial marker gene α-Actin and cTNT were significantly increased, and the Na⁺ current density on the surface of differentiated myocardial cell membrane was significantly increased. Meanwhile, the corresponding results of the KDM5B silent expression group were just opposite.

Conclusions

It indicated that enhanced KDM5B expression could promote the differentiation of BMSCs into cardiomyocytes and improve the differentiation efficiency by controlling H3K4 methylation levels.

Age‐related changes in mean corpuscular volumes in patients without anaemia: An analysis of large‐volume data from a single institute

Although the mean corpuscular volume (MCV) has been associated with various diseases, these associations in relation to the age‐related trends in MCV remain unclear. Therefore, we used a dataset with over one million values to identify the relationship between ageing and MCV changes. All laboratory data obtained between November 1998 and November 2019 at Chungbuk National University Hospital were retrospectively collected. After excluding cases with missing values for individual complete blood count parameters, outlier MCV values, and ages less than 1 year and more than 88 years, 977,335 MCV values were obtained from 309,393 patients. Principal component analysis of blood components with ages and analysis of the median value changes for each blood component across decade‐wise age groups were conducted to identify relationships between ageing and changes in blood components. The median values of MCV showed gradual increments with age. The linear relationship for patients aged 1–25 years had a larger slope than that for patients aged 26–88 years. For MCV, the equation for patients aged 1–25 years was 0.40*(age) + 81.24 in females and 0.45*(age) + 79.58 in males. The equation for patients aged 26–90 years was 0.04*(age) + 88.97 in females and 0.06*age + 88.30 in males. Among patients aged >40 years, the MCV value was higher in men than in women. Analysis of a large dataset showed that the MCV gradually increased with age and the linear relationship differed between patients aged 1–25 and 26–88 years.

A new insight into cell biological and biochemical changes through aging

After several years of extensive research, the main cause of aging is yet elusive. There are some theories about aging, such as stem cell aging, senescent cells accumulation, and neuro-endocrine theories. None of them is able to explain all changes that happen in cells and body through aging. By finding out the main cause of aging, it will be much easier to control, prevent and even reverse the aging process. Our cells, regardless of their replicative capacity, get old through aging and they have almost the same epigenetic age. Different cell signaling pathways contribute to aging. The most important one is mTORC1 that becomes hyperactive in cells that undergo aging. Other significant changes with age are lysosome accumulation, impaired autophagy, and mitophagy. Immune system undergoes gradual changes through aging including a shift from lymphoid to myeloid lineage production as well as increased IL-6 and TNF-α which lead to age-related weight loss and meta-inflammation. Additionally, our endocrine system also experiences some changes that should be taken into consideration when looking for the main cause of aging in the human body. In this review, we planned to summarize some of the changes that happen in cells and the body through aging.

Rodent diet aids and the fallacy of caloric restriction

Understanding the molecular mechanisms of normal aging is a prerequisite to significantly improving human health span. Caloric restriction (CR) can delay aging and has served as a yardstick to evaluate interventions extending life span. However, mice given unlimited access to food suffer severe obesity. Health gains from CR depend on control mice being sufficiently overweight and less obese mouse strains benefit far less from CR. Pharmacologic interventions that increase life span, including resveratrol, rapamycin, nicotinamide mononucleotide and metformin, also reduce body weight. In primates, CR does not delay aging unless the control group is eating enough to suffer from obesity-related disease. Human survival is optimal at a body mass index achievable without CR, and the above interventions are merely diet aids that shouldn't slow aging in healthy weight individuals. CR in humans of optimal weight can safely be declared useless, since there is overwhelming evidence that hunger, underweight and starvation reduce fitness, survival, and quality of life. Against an obese control, CR does, however, truly delay aging through a mechanism laid out in the following tumor suppression theory of aging.

Fate of Hematopoiesis During Aging. What Do We Really Know, and What are its Implications?

There is an ongoing shift in demographics such that older persons will outnumber young persons in the coming years, and with it age-associated tissue attrition and increased diseases and disorders. There has been increased information on the association of the aging process with dysregulation of hematopoietic stem (HSC) and progenitor (HPC) cells, and hematopoiesis. This review provides an extensive up-to date summary on the literature of aged hematopoiesis and HSCs placed in context of potential artifacts of the collection and processing procedure, that may not be totally representative of the status of HSCs in their in vivo bone marrow microenvironment, and what the implications of this are for understanding aged hematopoiesis. This review covers a number of interactive areas, many of which have not been adequately explored. There are still many unknowns and mechanistic insights to be elucidated to better understand effects of aging on the hematopoietic system, efforts that will take multidisciplinary approaches, and that could lead to means to ameliorate at least some of the dysregulation of HSCs and HPCs associated with the aging process. Graphical Abstract.

Maternal High Fat Diet and Diabetes Disrupts Transcriptomic Pathways That Regulate Cardiac Metabolism and Cell Fate in Newborn Rat Hearts

Background: Children born to diabetic or obese mothers have a higher risk of heart disease at birth and later in life. Using chromatin immunoprecipitation sequencing, we previously demonstrated that late-gestation diabetes, maternal high fat (HF) diet, and the combination causes distinct fuel-mediated epigenetic reprogramming of rat cardiac tissue during fetal cardiogenesis. The objective of the present study was to investigate the overall transcriptional signature of newborn offspring exposed to maternal diabetes and maternal H diet. Methods: Microarray gene expression profiling of hearts from diabetes exposed, HF diet exposed, and combination exposed newborn rats was compared to controls. Functional annotation, pathway and network analysis of differentially expressed genes were performed in combination exposed and control newborn rat hearts. Further downstream metabolic assessments included measurement of total and phosphorylated AKT2 and GSK3β, as well as quantification of glycolytic capacity by extracellular flux analysis and glycogen staining. Results: Transcriptional analysis identified significant fuel-mediated changes in offspring cardiac gene expression. Specifically, functional pathways analysis identified two key signaling cascades that were functionally prioritized in combination exposed offspring hearts: (1) downregulation of fibroblast growth factor (FGF) activated PI3K/AKT pathway and (2) upregulation of peroxisome proliferator-activated receptor gamma coactivator alpha (PGC1α) mitochondrial biogenesis signaling. Functional metabolic and histochemical assays supported these transcriptome changes, corroborating diabetes- and diet-induced cardiac transcriptome remodeling and cardiac metabolism in offspring. Conclusion: This study provides the first data accounting for the compounding effects of maternal hyperglycemia and hyperlipidemia on the developmental cardiac transcriptome, and elucidates nuanced and novel features of maternal diabetes and diet on regulation of heart health.

Identification of Human Very Small Embryonic like Stem Cells (VSELS) in Human Heart Tissue Among Young and Old Individuals

Very Small Embryonic-Like (VSEL) stem cells are a proposed pluripotent population, residing in adult tissues. VSELs have been described in multiple tissues including bone marrow, cord blood, and gonads. They exhibit multiple characteristics of embryonic stem cells including the ability to differentiate into cellular lineages of all three germ layers, including cardiomyocytes and vascular endothelial cells. However, their presence in adult solid organs such as heart in humans has not been established. VSELs are valuable source of stem cells for tissue regeneration and replacement of cells for turnover and usual wear-and-tear. The purpose of our study was to explore the existence of human VSELs (huVSELs) in human heart tissue and examine the changes in their prevalence with aging and cardiac disease. Human heart tissue, collected from healthy and ischemic heart disease subjects was examined for the prevalence of VSELS, defined as CD45-/CD133+/SSEA4+. Both epicardial and endocardial tissues were examined comparing VSEL numbers across different age groups. Our data confirm the existence of huVSELs in adult hearts with decreasing prevalence during aging. This is the first evidence of huVSELs in adult cardiac tissue. Cardiac huVSELs could be further explored in future studies to characterize their primitive potential and therapeutic potential in regenerative studies.

The Inhibition of CD39 and CD73 Cell Surface Ectonucleotidases by Small Molecular Inhibitors Enhances the Mobilization of Bone Marrow Residing Stem Cells by Decreasing the Extracellular Level of Adenosine

We have recently demonstrated that purinergic signaling in bone marrow (BM) microenvironment regulates mobilization of hematopoietic stem progenitor cells (HSPCs), mesenchymal stroma cells (MSCs), endothelial progenitor cells (EPCs), and very small embryonic like stem cells (VSELs) into the peripheral blood (PB). While extracellular adenosine triphosphate (ATP) promotes mobilization, its metabolite extracellular adenosine has an opposite effect. Since ATP is processed in extracellular space to adenosine by ectonucleotidases including cell surface expressed CD39 and CD73, we asked if inhibition of these enzymes by employing in vivo small molecular inhibitors ARL67156 and AMPCP of CD39 and CD73 respectively, alone or combined could enhance granulocyte stimulating factor (G-CSF)- and AMD3100-induced pharmacological mobilization of stem cells. Herein we report that pre-treatment of donor mice with CD39 and CD73 inhibitors facilitates the mobilization of HSPCs as well as other types of BM-residing stem cells. This data on one hand supports the role of purinergic signaling in stem cell trafficking, and on the other since both compounds are not toxic against human cells, they could be potentially employed in the clinic to enhance the mobilization of BM residing stem cells for clinical purposes.

Red Blood Cells Mean Corpuscular Volume (MCV) and Red Blood Distribution Width (RDW) Parameters as Potential Indicators of Regenerative Potential in Older Patients and Predictors of Acute Mortality - Preliminary Report

This study presents the statistical results of patients who had been recently discharged from hospital within one month after their treatment in the emergency department (ED). Using routine (14,881) MCV and RDW measurements and statistical tools, we could predict acute mortality in these patients (N = 1158), adjusted for age. It is likely that an increase in the MCV and RDW parameters may correlate in some of our older patients with a poor prognosis with an increased level of circulating IGF-I, which affects red blood cell parameters. The research presents the prognostic statistics of the analyzed clinical factors as well as speculates on the potential correlation of these parameters with the regenerative potential of stem-cell compartment. Analysis shows that both MCV and RDW are statistically significant (Area Under Curve [AUC], lower CI 95% >50%) predictors of acute mortality in ED patients. The classification of patients based on their MCV threshold (= 92.2 units) indicates a proper clinical prognosis in nearly 6 of 10 subjects (AUC >58%), whereas taking into account RDW (=13.8%) indicates a proper clinical prognosis in no more than 7 of 10 individuals. The report concludes that by employing strongly fitting (95%) quadratic modeling of the ORs against the biomarkers studied, one can notice a similar relationship between MCV and RDW as diagnostic tools to predict regenerative potential and clinical outcomes in older patients. Although RDW alone had a 10% higher diagnostic value in terms of predicting early death in the emergency department in patients that were admitted to the ED and subsequently hospitalized, also taking the MCV measurement improved accuracy in predicting clinical outcomes by 2.5% compared to RDW alone.

The effects of growth hormone on therapy resistance in cancer

Pituitary derived and peripherally produced growth hormone (GH) is a crucial mediator of longitudinal growth, organ development, metabolic regulation with tissue specific, sex specific, and age-dependent effects. GH and its cognate receptor (GHR) are expressed in several forms of cancer and have been validated as an anti-cancer target through a large body of in vitro, in vivo and epidemiological analyses. However, the underlying molecular mechanisms of GH action in cancer prognosis and therapeutic response had been sparse until recently. This review assimilates the critical details of GH-GHR mediated therapy resistance across different cancer types, distilling the therapeutic implications based on our current understanding of these effects.

NLRP3 inflammasome couples purinergic signaling with activation of the complement cascade for the optimal release of cells from bone marrow

The mechanisms that regulate egress of hematopoietic stem/progenitor cells (HSPCs) into peripheral blood (PB) in response to stress, inflammation, tissue/organ injury, or administration of mobilization-inducing drugs are still not well understood, and because of the importance of stem cell trafficking in maintaining organism homeostasis, several complementary pathways are believed to be involved. Our group proposes that mobilization of HSPCs is mainly a result of sterile inflammation in the bone marrow (BM) microenvironment in response to pro-mobilizing stimuli and that during the initiation phase of the mobilization process BM-residing cells belonging to the innate immunity system, including granulocytes and monocytes, release danger-associated molecular pattern molecules (DAMPs, also known as alarmins), reactive oxygen species (ROS), as well as proteolytic and lipolytic enzymes. These factors together orchestrate the release of HSPCs into PB. One of the most important DAMPs released in the initiation phase of mobilization is extracellular adenosine triphosphate, a potent activator of the inflammasome. As a result of its activation, IL-1β and IL-18 as well as other pro-mobilizing mediators, including DAMPs such as high molecular group box 1 (Hmgb1) and S100 calcium-binding protein A9 (S100a9), are released. These DAMPs are important activators of the complement cascade (ComC) in the mannan-binding lectin (MBL)-dependent pathway. Specifically, Hmgb1 and S100a9 bind to MBL, which leads to activation of MBL-associated proteases, which activate the ComC and in parallel also trigger activation of the coagulation cascade (CoaC). In this review, we will highlight the novel role of the innate immunity cell-expressed NLRP3 inflammasome, which, during the initiation phase of HSPC mobilization, couples purinergic signaling with the MBL-dependent pathway of the ComC and, in parallel, the CoaC for optimal release of HSPCs. These data are important to optimize the pharmacological mobilization of HSPCs.

Potential role of E4orf1 protein in aging-associated impairment in glycemic control

Aging constitutes a major risk factor for the development of type-2 diabetes (T2D) where glucose tolerance declines with age, resulting in a high prevalence of T2D and impaired glucose tolerance in the elderly population. Currently more than half of the 20 million U.S. adults with T2D are above the age of 60, and the largest increase in T2D prevalence is expected in the elderly. Obesity is a causative factor for T2D associated insulin resistance and hyperglycemia. Furthermore, the aging process is accelerated by hyperglycemia and effective treatment options are limited for the vulnerable aging population. One of the mechanisms contributing to aging associated hyperglycemia is resistance to insulin-mediated glucose disposal. Chronic hyperglycemia also accelerates aging by increasing pro-inflammatory milieu leading to impaired immune function. Although currently available anti-diabetic agents improve glycemic control, they have potential serious side effects in some cases. Therefore, additional and better drugs are urgently needed for treatment of insulin resistance and aging associated health risk factors. This review presents the novel use of a microbial protein, E4orf1 as a potential anti-diabetic agent, which functions independent of insulin and obesity, highlighting the role of unique sources for future drug development.

Analysis of the Paternally-Imprinted DLK1-MEG3 and IGF2-H19 Tandem Gene Loci in NT2 Embryonal Carcinoma Cells Identifies DLK1 as a Potential Therapeutic Target

The paternally-imprinted genes insulin-like growth factor 2 (IGF2), H19, delta-like homologue 1 (DLK1), and maternally-expressed gene 3 (MEG3) are expressed from the tandem gene loci IGF2-H19 and DLK1-MEG3, which play crucial roles in initiating embryogenesis and development. The erasure of imprinting (EOI) at differentially methylated regions (DMRs) which regulate the expression of these genes maintains the developmental quiescence of primordial germ cells (PGCs) migrating through the embryo proper during embryogenesis and prevents them from forming teratomas. To address the potential involvement of the IGF2-H19 and DLK1-MEG3 loci in the pathogenesis of embryonal carcinoma (EC), we investigated their genomic imprinting at DMRs in the human PGC-derived EC cell line NTera-2 (NT2). We observed EOI at the IGF2-H19 locus and, somewhat to our surprise, a loss of imprinting (LOI) at the DLK1-MEG3 locus. As a result, NT2 cells express imprinted gene ratios from these loci such that there are i) low levels of the proliferation-promoting IGF2 relative to ii) high levels of the proliferation-inhibiting long noncoding RNA (lncRNA) H19 and iii) high levels of proliferation-promoting DLK1 relative to iv) low levels of the proliferation-inhibiting lncRNA MEG3. Consistent with this pattern of expression, the knockdown of DLK1 mRNA by shRNA resulted in decreased in vitro cell proliferation and in vivo tumor growth as well as decreased in vivo organ seeding by NT2 cells. Furthermore, treatment of NT2 cells with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (5-azaD) inhibited their proliferation. This inhibition was accompanied by changes in expression of both tandem gene sets: a decrease in the expression of DLK1 and upregulation of the proliferation-inhibiting lncRNA MEG3, and at the same time upregulation of IGF2 and downregulation of the lncRNA H19. These results suggest that the DLK1-MEG3 locus, and not the IGF2-H19 locus, drives the tumorigenicity of NT2 cells. Based on these results, we identified DLK1 as a novel treatment target for EC that could be downregulated by 5-azaD.

Plausible Links Between Metabolic Networks, Stem Cells, and Longevity

Aging is an inevitable consequence of life, and all multicellular organisms undergo a decline in tissue and organ functions as they age. Several well-known risk factors, such as obesity, diabetes, and lack of physical activity that lead to the cardiovascular system, decline and impede the function of vital organs, ultimately limit overall life span. Over recent years, aging research has experienced an unparalleled growth, particularly with the discovery and recognition of genetic pathways and biochemical processes that control to some extent the rate of aging.In this chapter, we focus on several aspects of stem cell biology and aging, beginning with major cellular hallmarks of aging, endocrine regulation of aging and its impact on stem cell compartment, and mechanisms of increased longevity. We then discuss the role of epigenetic modifications associated with aging and provide an overview on a most recent search of antiaging modalities.

Cancer from the perspective of stem cells and misappropriated tissue regeneration mechanisms

Tumorigenesis can be considered as pathologically misappropriated tissue regeneration. In this review we will address some unresolved issues that support this concept. First, we will address the issue of the identity of cancer-initiating cells and the presence of cancer stem cells in growing tumors. We will also ask are there rare and distinct populations of cancer stem cells in established tumor cell lines, or are all of the cells cancer stem cells? Second, the most important clinical problem with cancer is its metastasis, and here a challenging question arises: by employing radio-chemotherapy for tumor treatment, do we unintentionally create a prometastatic microenvironment in collateral organs? Specifically, many factors upregulated in response to radio-chemotherapy-induced injury may attract highly migratory cancer cells that survived initial treatment. Third, what is the contribution of normal circulating stem cells to the growing malignancy? Do circulating normal stem cells recognize a tumor as a hypoxia-damaged tissue that needs vascular and stromal support and thereby contribute to tumor expansion? Fourth, is it reasonable to inhibit only one prometastatic ligand-receptor axis when cancer stem cells express several receptors for several chemotactic factors that may compensate for inhibition of the targeted receptor? Fifth, since most aggressive cancer cells mimic early-development stem cells, which properties of embryonic stem cells are retained in cancer cells? Would it be reasonable to inhibit cancer cell signaling pathways involved in the migration and proliferation of embryonic stem cells? We will also briefly address some new players in cancerogenesis, including extracellular microvesicles, bioactive phospholipids, and extracellular nucleotides.

Cardiac regenerative capacity is age- and disease-dependent in childhood heart disease

Objective

We sought to define the intrinsic stem cell capacity in pediatric heart lesions, and the effects of diagnosis and of age, in order to inform evidence-based use of potential autologous stem cell sources for regenerative medicine therapy.

Methods

Ventricular explants derived from patients with hypoplastic left heart syndrome (HLHS), tetralogy of Fallot (TF), dilated cardiomyopathy (DCM) and ventricular septal defect (VSD) were analyzed following standard in vitro culture conditions, which yielded cardiospheres (C-spheres), indicative of endogenous stem cell capacity. C-sphere counts generated per 5 mm3 tissue explant and the presence of cardiac progenitor cells were correlated to patient age, diagnosis and echocardiographic function.

Results

Cardiac explants from patients less than one year of age with TF and DCM robustly generated c-kit- and/or vimentin-positive cardiac mesenchymal cells (CMCs), populating spontaneously forming C-spheres. Beyond one year of age, there was a marked reduction or absence of cardiac explant-derivable cardiac stem cell content in patients with TF, VSD and DCM. Stem cell content in HLHS and DCM strongly correlated to the echocardiographic function in the corresponding ventricular chamber, with better echocardiographic function correlating to a more robust regenerative cellular content.

Conclusions

We conclude that autologous cardiomyogenic potential in pediatric heart lesions is robust during the first year of life and uniformly declines thereafter. Depletion of stem cell content occurs at an earlier age in HLHS with the onset of ventricular failure in a chamber-specific pattern that correlates directly to ventricular dysfunction. These data suggest that regenerative therapies using autologous cellular sources should be implemented in the neonatal period before the potentially rapid onset of single ventricle failure in HLHS or the evolution of biventricular failure in DCM.

Novel View on Umbilical Cord Blood and Maternal Peripheral Blood-an Evidence for an Increase in the Number of Circulating Stem Cells on Both Sides of the Fetal-Maternal Circulation Barrier

Umbilical cord blood (UCB) is a rich source of stem cells, including hematopoietic stem cells (HSCs), mesenchymal stem cells (MSCs), endothelial progenitors cells (EPCs), and very small embryonic-like stem cells (VSELs). These cells most likely are mobilized into UCB in response to hypoxia and delivery stress. We have hypothesized that they may play a role in repairing certain tissue/organ injuries that occur in the newborn child after delivery. Here we asked whether delivery also mobilizes stem cells into maternal blood, as the mother also experiences hypoxia and several types of internal tissue injuries, particularly in the reproductive tract. We observed that the number of HSCs, MSCs, EPCs, and VSELs increases in maternal blood at 24 h after physiological delivery (n = 17). Based on this observation, we propose that delivery stress is associated with an increase in the number of circulating stem cells, not only on the fetal side but also on the maternal side of the fetal–maternal circulatory barrier.

The Emerging Link Between the Complement Cascade and Purinergic Signaling in Stress Hematopoiesis

Innate immunity plays an important role in orchestrating the immune response, and the complement cascade (ComC) is a major component of this ancient defense system, which is activated by the classical-, alternative-, or mannan-binding lectin (MBL) pathways. However, the MBL-dependent ComC-activation pathway has been somewhat underappreciated for many years; recent evidence indicates that it plays a crucial role in regulating the trafficking of hematopoietic stem/progenitor cells (HSPCs) by promoting their egress from bone marrow (BM) into peripheral blood (PB). This process is initiated by the release of danger-associated molecular patterns (DAMPs) from BM cells, including the most abundant member of this family, adenosine triphosphate (ATP). This nucleotide is well known as a ubiquitous intracellular molecular energy source, but when secreted becomes an important extracellular nucleotide signaling molecule and mediator of purinergic signaling. What is important for the topic of this review, ATP released from BM cells is recognized as a DAMP by MBL, and the MBL-dependent pathway of ComC activation induces a state of "sterile inflammation" in the BM microenvironment. This activation of the ComC by MBL leads to the release of several potent mediators, including the anaphylatoxins C5a and _desArgC5a, which are crucial for egress of HSPCs into the circulation. In parallel, as a ligand for purinergic receptors, ATP affects mobilization of HSPCs by activating other pro-mobilizing pathways. This emerging link between the release of ATP, which on the one hand is an activator of the MBL pathway of the ComC and on the other hand is a purinergic signaling molecule, will be discussed in this review. This mechanism plays an important role in triggering defense mechanisms in response to tissue/organ injury but may also have a negative impact by triggering autoimmune disorders, aging of HSPCs, induction of myelodysplasia, and graft-versus-host disease after transplantation of histoincompatible hematopoietic cells.

MECHANISMS IN ENDOCRINOLOGY: Lessons from growth hormone receptor gene-disrupted mice: are there benefits of endocrine defects?

Growth hormone (GH) is produced primarily by anterior pituitary somatotroph cells. Numerous acute human (h) GH treatment and long-term follow-up studies and extensive use of animal models of GH action have shaped the body of GH research over the past 70 years. Work on the GH receptor (R)-knockout (GHRKO) mice and results of studies on GH-resistant Laron Syndrome (LS) patients have helped define many physiological actions of GH including those dealing with metabolism, obesity, cancer, diabetes, cognition and aging/longevity. In this review, we have discussed several issues dealing with these biological effects of GH and attempt to answer the question of whether decreased GH action may be beneficial.

Novel evidence that extracellular nucleotides and purinergic signaling induce innate immunity-mediated mobilization of hematopoietic stem/progenitor cells

Pharmacological mobilization of hematopoietic stem progenitor cells (HSPCs) from bone marrow (BM) into peripheral blood (PB) is a result of mobilizing agent-induced “sterile inflammation” in the BM microenvironment due to complement cascade (ComC) activation. Here we provide evidence that ATP, as an extracellular nucleotide secreted in a pannexin-1-dependent manner from BM cells, triggers activation of the ComC and initiates the mobilization process. This process is augmented in a P2X7 receptor-dependent manner, and P2X7-KO mice are poor mobilizers. Furthermore, after its release into the extracellular space, ATP is processed by ectonucleotidases: CD39 converts ATP to AMP, and CD73 converts AMP to adenosine. We observed that CD73-deficient mice mobilize more HSPCs than do wild-type mice due to a decrease in adenosine concentration in the extracellular space, indicating a negative role for adenosine in the mobilization process. This finding has been confirmed by injecting mice with adenosine along with pro-mobilizing agents. In sum, we demonstrate for the first time that purinergic signaling involving ATP and its metabolite adenosine regulate the mobilization of HSPCs. Although ATP triggers and promotes this process, adenosine has an inhibitory effect. Thus, administration of ATP together with G-CSF or AMD3100 or inhibition of CD73 by small molecule antagonists may provide the basis for more efficient mobilization strategies.

Of Cytometry, Stem Cells and Fountain of Youth

Outlined are advances of cytometry applications to identify and sort stem cells, of laser scanning cytometry and ImageStream imaging instrumentation to further analyze morphometry of these cells, and of mass cytometry to classify a multitude of cellular markers in large cell populations. Reviewed are different types of stem cells, including potential candidates for cancer stem cells, with respect to their "stemness", and other characteristics. Appraised is further progress in identification and isolation of the "very small embryonic-like stem cells" (VSELs) and their autogenous transplantation for tissue repair and geroprotection. Also assessed is a function of hyaluronic acid, the major stem cells niche component, as a guardian and controller of stem cells. Briefly appraised are recent advances and challenges in the application of stem cells in regenerative medicine and oncology and their future role in different disciplines of medicine, including geriatrics.

A novel potential role of pituitary gonadotropins in the pathogenesis of human colorectal cancer

Background

Colorectal cancer (CRC) is a leading cause of death in the western world, and its incidence increases with patient age. It is also known that with age there occur changes in the levels of certain hormones, including an increase in the secretion of pituitary gonadotropins (PtGs) as a result of the loss of gonadal hormone feedback. We recently reported that functional PtG receptors are expressed in human lung cancer cells, rhabdomyosarcoma cells, and malignant hematopoietic stem cells.

Findings

Here we report for the first time that the receptors for follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are expressed in primary tumor samples isolated from CRC patients as well as in the established human CRC cell lines HTC116 and HTB37. Moreover, we also report that PtGs stimulate chemotaxis, adhesion, and proliferation of these cell lines.

Conclusions

Our results suggest that PtGs play an important and underappreciated role in CRC pathogenesis, and we call for further studies to better define their role in gastrointestinal malignancies and their direct effect on putative CRC cancer stem cells.

Novel evidence that pituitary sex hormones regulate migration, adhesion, and proliferation of embryonic stem cells and teratocarcinoma cells

The pituitary sex hormones (SexHs): follicle-stimulating hormone (FSH), luteinizing hormone (LH), and prolactin (PRL) regulate several functions crucial for reproduction, including oogenesis, spermatogenesis, and lactation. An important source of prolactin-like hormones, known as lactogens, is the placenta, and lactogens bind to the PRL receptor (PRLR) with high affinity and thereby mimic the actions of PRL. Recently, it has been demonstrated that pituitary SexHs were involved in metastatic lung cancer, certain sarcomas, and leukemia. In the present study we aimed to investigate whether FSH, LH, and PRL were able to stimulate stem cells involved in early development. To address this issue we employed a murine embryonic stem cell line (ES-D3) as well as two teratocarcinoma cell lines, P19 (murine) and NTera2 (human). We determined that all these cells expressed SexH receptors at the mRNA and protein levels and that stimulation of these receptors induced phosphorylation of p42/44 MAPK, p38 MAPK, and AKT. Moreover, ES-D3, P19, and NTera2 cells responded with increased migration and adhesion to physiological concentrations of pituitary SexHs. In view of these findings we proposed that maternal-derived pituitary SexHs regulate the biology of stem cells involved in early development.