Glycobiological insights in characterization and targeting of umbilical cord blood derived stem cells

Stem cells have a unique ability to both self-renew and differentiate into diverse cell types and they harbor remarkable potential in therapeutic applications. Stem cells can be isolated from various sources of both embryonic and adult origin. During the past decade, research on stem cells has rapidly expanded, but many issues of stem cell biology and their clinical use remain unresolved. There is a need for methods to thoroughly characterize therapeutic cell populations, to better distinguish them from other cells, and to control variation within and between different cell preparations. The surface of stem cells, like all other human cell surfaces, is covered by a complex network of glycans. This is the outmost layer of cells, called the glycocalyx. The glycocalyx is characteristic to and different in every cell type and reflects even subtle changes in cell behaviour and for example cell differentiation. Cell surface glycans are the first cellular components encountered by approaching cells, pathogens, signalling molecules and other binders, making the terminal glycan units key players in cell interactions and signalling. Due to their prominent cell surface localization, glycan epitopes can be utilized for identifying and isolating specific cell types from heterogeneous populations. The aim of this study was to characterize relevant glycan structures on umbilical cord blood derived stem and progenitor cells, to study how they are regulated and to determine their influence on stem cell biology. As decribed in the original publications of this study, we were able to characterize two novel glycan determinants, O-GlcNAc and linear poly-LacNAc, on umbilical cord blood derived mesenchymal stromal cells (UCB-MSCs). We further discovered that galectins-1 and -3 secreted by these cells are bound on the cell surface and that the cell surface galectin-1 interacts with P-selectin. This interaction is likely to play a role in the immunomodulatory homing of UCB-MSCs to sites of injury or inflammation. In addition, we present the effects and potential use of metabolic glycoengineering of UCB-MSC. Taken together, these studies provide new insights into the glycobiology of UCB derived stem and progenitor cells. This information may help to distinguish better cell populations for distinct therapeutic applications and to design therapeutic cells with enhanced biological properties.Kantasolut ovat erilaistumattomia soluja, joilla on ainutlaatuinen kyky jakautua ja erilaistua erilaisiksi solutyypeiksi ja edelleen kudoksiksi. Kantasoluista odotetaankin tulevaisuudessa uusia hoitomuotoja moniin vaikeisiin sairauksiin, kuten diabetekseen, Parkinsonin tautiin ja MS tautiin. Kantasoluja on löydetty pienessä määrin lähes kaikista elimistön eri kudoksista. Erityisen rikkaita kantasolulähteitä alkion kantasolujen lisäksi ovat luuydin ja istukkaveri, joiden kantasolut luokitellaan aikuisen kantasoluiksi. Vaikka kantasoluja on laajasti tutkittu, ei niiden biokemiallisia ominaisuuksia vielä täysin ymmärretä. Kaikkien solujen pinta on sokerirakenteiden verkoston peitossa. Tämä solun pinnan sokerirakenneverkosto on jokaisella solutyypillä erilainen ja sen perusteella voidaan tunnistaa eri solutyyppejä. Solun pinnan sokerit välittävät solun vuorovaikutuksia toisien solujen ja solun ympäristön kanssa. Solun pinnan sokerit myös muuntuvat nopeasti solun tilanteen muuttuessa, esimerkiksi kantasolun erilaistuessa, tai solun vastatessa sen ympäristöstä tulleisiin ärsykkeisiin. Tämän tutkimuksen tarkoituksena oli kartoittaa istukkaveren kantasolujen pinnan sokerirakenteita, sekä tutkia niiden säätelymekanismeja ja merkitystä kantasoluille. Löysimme istukkaveren mesenkymaalisten kantasolujen pinnalta kaksi uutta sokerirakennetta; O-glykosidisella sidoksella kiinnittyneen N-asetyyliglukosamiinin, sekä lineaarisen poly-N-asetyylilaktosamiinin. Havaitsimme myös, että näiden solujen pinnalla ilmentyy kaksi tärkeää sokerirakenteisiin kiinnittyvää proteiinia, galektiini-1 ja galektiini-3, jotka voivat kiinnittyä löydettyyn poly-N-asetyylilaktosamiinirakenteeseen. Näiden galektiinien on todettu kuvastavan mesenkymaalisten kantasolujen terapeuttisia ominaisuuksia. Lisäksi tutkimuksemme osoitti, että solun pinnan galektiini-1 sitoutuu P-selektiiniin, joka ohjaa kantasolujen kiinnittymistä vaurioituneisiin tai tulehtuneisiin kudoksiin. Tutkimme myös miten solun pinnan sokerirakenteiden muokkaus aineenvaihdunnan välityksellä vaikuttaa solun ilmentämien sokeriverkostojen koostumukseen. Jotta kantasoluhoitoja voidaan turvallisesti kehittää, tarvitaan tehokkaita menetelmiä näiden solujen eristämiseen ja tunnistamiseen. Tämä tutkimus toi esille uusia lupaavia näkökulmia kantasolujen biokemiallisista ominaisuuksista ja näitä tuloksia voidaan hyödyntää tutkittaessa kantasolujen käyttöä erilaisten sairauksien hoidossa

Sex and Iron Modify Fibroblast Growth Factor 23 Concentration in 1-Year-Old Children

Context: Fibroblast growth factor 23 (FGF23) plays an important role in phosphate homeostasis, but its regulation is inadequately characterized. Objective: To examine FGF23 regulators, especially sex and iron status, in early childhood. Design: A cross-sectional study involving 1-year-old children. Setting and Participants: Healthy term infants with a birth weight appropriate for gestational age were recruited to an ongoing vitamin D trial at Katiloopisto Maternity Hospital, Helsinki, Finland. At 12-month follow-up visits, serum FGF23, 25-hydroxyvitamin D (25OHD), phosphate, ionized calcium, parathyroid hormone, and iron status were measured. All 721 children (51% girls) with complete data were included. Main Outcome Measures: Intact and C-terminal FGF23 concentrations and iron status at 1 year of age. Results: Intact FGF23 was greater in girls than in boys [median, 44.4 pg/mL; interquartile range (IQR), 36.8 to 51.9; median, 40.9 pg/mL; IQR, 34.5 to 49.0, respectively; P <0.001]. C-terminal FGF23 was similar in boys and girls (median, 2.8 pmol/L; IQR, 2.1 to 3.7; median, 2.9 pmol/L; IQR, 2.2 to 3.7, respectively; P = 0.393). The iron concentration was positively associated with intact FGF23 and was the strongest modifier of intact FGF23 (regression coefficient, 0.498; 95% confidence interval, 0.333 to 0.663; P <0.001) with ferritin, season, ionized calcium, 25OHD, and sex as other covariates. The association between iron and C-terminal FGF23 was inversely related (regression coefficient, -0.072; 95% confidence interval, -0.092 to -0.051; P <0.001). Conclusions: At 1 year of age, FGF23 status was different in girls and boys, with intact FGF23 concentrations higher in girls. Iron modified FGF23 concentrations, with intact FGF23 higher and C-terminal lower, in those with greater iron concentrations.Peer reviewe

Towards evidence-based vitamin D supplementation in infants : vitamin D intervention in infants (VIDI) - study design and methods of a randomised controlled double-blinded intervention study

Background: Vitamin D is important for bone mass accrual during growth. Additionally, it is considered a requirement for a multitude of processes associated with, for example, the development of immunity. Many countries apply vitamin D supplementation strategies in infants, but the guidelines are not based on scientific evidence and aim at prevention of rickets. It remains unclear whether the recommended doses are sufficient for the wide array of other effects of vitamin D. The VIDI trial performed in Finland is the first large randomised controlled study for evaluation of the effects of different vitamin D supplemental doses in infancy on: 1. bone strength 2. infections and immunity 3. allergy, atopy and asthma 4. cognitive development 5. genetic regulation of mineral homeostasis Methods/Design: VIDI, a randomised controlled double-blinded single-centre intervention study is conducted in infants from the age of 2 weeks to 24 months. Participants, recruited at Helsinki Maternity Hospital, are randomised to receive daily either 10 mu g (400 IU) or 30 mu g (1 200 IU) of vitamin D3 supplementation. Both groups are assessed at 6 months of age for calcium homeostasis, and at 12 and 24 months of age for parameters associated with bone strength, growth, developmental milestones, infections, immunity, atopy-related diseases, and genetic factors involved in these functions. Discussion: The study enables evaluation of short and long term effects of supplemental vitamin D on growth, immune functions and skeletal and developmental parameters in infants, and the effects of genetic factors therein. The results enable institution of evidence-based guidelines for vitamin D supplementation in infancy.Peer reviewe

High-Dose Vitamin D Supplementation Does Not Prevent Allergic Sensitization of Infants

Objective To investigate the effect of vitamin D supplementation dose on allergic sensitization and allergic diseases in infants, and to evaluate whether vitamin D status in pregnancy and at birth are associated with infant allergy outcomes. Study design Altogether, 975 infants participated in a randomized, controlled trial of daily vitamin D supplementation of 10 mu g (400 IU) or 30 mu g (1200 IU) from the age of 2 weeks. At 12 months of age, food and aeroallergen IgE antibodies were measured, and the occurrence of allergic diseases and wheezing were evaluated. Results We found no differences between the vitamin D supplementation groups in food (OR, 0.98; 95% CI, 0.66-1.46) or aeroallergen sensitization at 12 months (OR, 0.76; 95% CI,0.34-1.71). Allergic diseases or wheezing did not differ between groups, except for milk allergy which occurred more often in infants administered 30 mu g vitamin D compared with the 10 mu g dose (OR, 2.23; 95% CI, 1.00-4.96). Infants with high cord blood 25-hydroxyvitamin D (>= 100 nmol/L) had a higher risk of food allergen sensitization compared with those with lower 25(OH)D concentration (75-99.9 nmol/L; OR, 2.00; 95% CI, 1.19-3.39). Conclusions High-dose vitamin D supplementation did not prevent allergic sensitization, allergic diseases, or wheezing during the first year of life. In contrast, we observed an increased risk of milk allergy in infants randomized to higher vitamin D supplementation, and an increased risk of allergic sensitization in infants with high cord blood vitamin D status, indicating a possible adverse effect of high concentrations of vitamin D.Peer reviewe

Maternal vitamin D status, gestational diabetes and infant birth size

Background: Maternal vitamin D status has been associated with both gestational diabetes mellitus (GDM) and fetal growth restriction, however, the evidence is inconsistent. In Finland, maternal vitamin D status has improved considerably due to national health policies. Our objective was to compare maternal 25-hydroxy vitamin D concentrations [25(OH)D] between mothers with and without GDM, and to investigate if an association existed between maternal vitamin D concentration and infant birth size. Methods: This cross-sectional study included 723 mother-child pairs. Mothers were of Caucasian origin, and infants were born at term with normal birth weight. GDM diagnosis and birth size were obtained from medical records. Maternal 25(OH)D was determined on average at 11 weeks of gestation in pregnancy and in umbilical cord blood (UCB) at birth. Results: GDM was observed in 81 of the 723 women (11%). Of the study population, 97% were vitamin D sufficient [25(OH)D >= 50 nmol/L]. There was no difference in pregnancy 25(OH)D concentration between GDM and non-GDM mothers (82 vs 82 nmol/L, P = 0.99). Regression analysis confirmed no association between oral glucose tolerance test results and maternal 25(OH)D (P > 0.53). Regarding the birth size, mothers with optimal pregnancy 25(OH)D (>= 80 nmol/L) had heavier newborns than those with suboptimal pregnancy 25(OH)D (P = 0.010). However, mothers with optimal UCB 25(OH) D had newborns with smaller head circumference than those with suboptimal 25(OH)D (P = 0.003), which was further confirmed as a linear association (P = 0.024). Conclusions: Maternal vitamin D concentration was similar in mothers with and without GDM in a mostly vitamin D sufficient population. Associations between maternal vitamin D status and birth size were inconsistent. A sufficient maternal vitamin D status, specified as 25(OH)D above 50 nmol/L, may be a threshold above which the physiological requirements of pregnancy are achieved.Peer reviewe

High Pregnancy, Cord Blood, and Infant Vitamin D Concentrations May Predict Slower Infant Growth

Context: The relationship of maternal and infant 25-hydroxyvitamin D concentration [25(OH)D] with infant growth is unclear. Objective: Our objective was to explore whether 25(OH)D in pregnancy, umbilical cord blood (UCB), or in infancy was associated with infant growth. Design: This study involved 798 healthy infants and their mothers in Finland. We assessed 25(OH)D during pregnancy, from UCB at birth, and from the infant at the age of 12 months. Main Outcome Measures: Infant length, weight, length-adjusted weight, and head circumference at 6 and 12 months and midupper-arm circumference at 12 months. Results: Of the mothers and infants, 96% and 99% were vitamin D sufficient [25(OH)D >= 50 nmol/L], respectively. Mothers with pregnancy 25(OH)D >125 nmol/L had the shortest, lightest (in weight), and thinnest (in length-adjusted weight) infants at 6 months (P for all <0.05). For each 10 nmol/L higher UCB 25(OH)D, the infants were 0.03 SD score (SDS) shorter at 6 months (95% CI -0.05 to -0.01), adjusted for birth size, infant 25(OH)D, and parental height. Higher UCB 25(OH)D associated with smaller head circumference at 6 and 12 months (P for all 125 nmol/L had the thinnest infants at 12 months (P = 0.021). For each 10 nmol/L higher infant 25(OH)D, the infants were 0.03 SDS lighter (-0.05 to -0.01) and 0.03 SDS thinner (-0.05 to 0.00) at 12 months. Conclusions: Our results suggest that high pregnancy, cord blood, and infant vitamin D concentration may have disadvantageous effects on infant growth.Peer reviewe

Food and Nutrient Intake and Nutrient Sources in 1-Year-Old Infants in Finland : A Cross-Sectional Analysis

The infant diet has short- and long-term health consequences. Updated data regarding the dietary intake of Finnish infants are lacking. The objectives of this study were to describe infant food and nutrient intake and to identify food sources of the nutrients. Altogether, 739 healthy infants were studied. Dietary intake and breastfeeding frequency were assessed with a three-day food record at 1 year of age. Dietary intake was calculated separately for non-breastfed and breastfed infants. One-third (36%) of the infants were partially breastfed and 95% consumed mass-produced baby foods. The infants' diet consisted mainly of infant formula, dairy milk, porridges, fruit and berry foods, and meat dishes. The mean vegetable, fruit and berry consumption was 199 g/day. Most nutrient intakes were adequate except for fat, linoleic acid, vitamin D and iron from food. Mean sucrose intake, as a percentage of total energy intake (E%), was 5-6 E%. High protein intake (>20 E%) was observed in 19% of non-breastfed infants. Overall, the infants' diet was favorable since vegetable and fruit consumption was reasonably high and nutrient intake was mostly adequate. However, the fat intake was lower, and protein intake higher than recommended. Increasing the consumption of vegetable oils and reducing the intake of red meat and dairy milk may further improve the diet of 1-year-olds.Peer reviewe

Season, dietary factors, and physical activity modify 25-hydroxyvitamin D concentration during pregnancy

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