Antimicrobial characteristics and biocompatibility of the surgical sutures coated with biosynthesized silver nanoparticles

Surgical sutures play important role during the wound healing of the surgical sites which are known to be sensitive to microbial infections. Silver nanoparticles (AgNPs) have been recently used as promising agents against multiple-drug resistant microorganisms. This study was designed to coat the sutures with silver nanoparticles obtained via a green synthesis approach. Microbial-mediated biological synthesis of AgNPs were carried out ecofriendly using Streptomyces sp. AU2 cell-free extract and deposited on silk sutures through an in situ process. Sutures coated with biosyntehsized AgNP (bio-AgNP coated sutures) were characterized using Scanning Electron Microscopy (SEM) and elemantal analysis were carried out using Energy Dispersive X-ray Spectroscopy (EDS). The silver amount released by the bio-AgNP coated sutures was calculated by Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) throughout a degradation process. Antimicrobial potential of the bio-AgNP coated sutures was determined against common pathogenic microorganisms Candida albicans, Escherichia coli and Staphylococcus aureus. To determine the biocompatibility/cytotoxicty of the bio-AgNP coated sutures, the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium) assay was used through an indirect test method; that the elutions obtained by the extraction of the sutures at 1, 4, 8 and 10. days and were placed in contact with 3T3 fibroblast cell culture. To best of our knowledge, this is the first report about coating of the nonabsorbable silk sutures with silver nanoparticles biosynthesized using a microbial extract.     

Biosynthesis of silver nanoparticles using Malva parviflora and their antifungal activity

Cheeseweed mallow (Malva parviflora L.) was used to biosynthesize silver nanoparticles. The biosynthesized silver nanoparticles were classified by UV–vis Spectroscopy and Fourier-Transform Infrared Spectroscopy (FT-IR). The shape and size distribution were visualized by Transmission Electron Microscopy (TEM), Field Emission Scanning Electron Microscopy (FE-SEM), and Zeta potential analysis. The chemical composition of M. parviflora leaf extract was identified by Gas Chromatography and Mass Spectroscopy (GC/MS). Finally, in vitro antifungal assay was done to assess the potential of biosynthesized silver nanoparticles and crude leaf extract of M. parviflora for inhibiting the mycelial growth of phytopathogenic fungi. The UV–vis analysis manifests the formation of silver nanoparticles. FTIR analysis established that chemicals of the leaf extract stabilized the biosynthesized silver nanoparticles by binding with the free silver ions. The TEM, FE-SEM and zeta potential analyzer confirmed that the biosynthesized silver nanoparticles were mostly spherical with an average diameter of 50.6 nm. The biosynthesized silver nanoparticles and leaf extract of M. parviflora effectively mitigate the mycelial growth of Helminthosporium rostratum, Fusarium solani, Fusarium oxysporum, and Alternaria alternata. The maximum reduction in mycelial growth by biosynthesized nanoparticles was observed against H. rostratum (88.6%). Whereas, the leaf extract of M. parviflora was most effective against F. solani (65.3%). Thus, the biosynthesis of nanoparticle assisted by M. parviflora is a feasible and eco-friendly method for the synthesis of silver nanoparticles. Further the silver nanoparticles and leaf extract of M. parviflora could be explored for the development of the fungicide.     

Placental Transfer of Lactate,Glucose and 2-deoxyglucose in Control and Diabetic Wistar Rats

Placental transfer of lactate, glucose and 2-deoxyglucose was examined employing the in situ perfused placenta. Control and streptozotocin induced diabetic Wistar rats were infused with [U¹⁴C]-glucose and [³H]-2-deoxyglucose (2DG). The fetal side of the placenta was perfuseci with a cell free medium and glucose uptake was calculated in the adjacent fetuses. Despite the 5-fold higher maternal plasma glucose concentration in the diabetic dams the calculated fetal glucose metabolic index was not significantly different between the 2 groups. Placental blood flow was reduced in the diabetic animals compared with controls but reduction of transfer of [U¹⁴C]-glucose and [³H]-2-deoxyglucose and endogenously derived [¹⁴C]-Lactate to the fetal compartment, could not be accounted for by reduced placental blood flow alone. There was no significant net production or uptake of lactate into the perfusion medium that had perfused the fetal side of the placenta in either group. The plasma lactate levels in the fetuses adjacent to the perfused placenta were found to be higher than in the maternal plasma and significantly higher in the fetuses of the diabetic group compared with control group. In this model the in situ perfused placenta does not secrete significant quantities of lactate into the fetal compartment in either the control or diabetic group.     

Experimental models of maternal–fetal interface and their potential use for nanotechnology applications

During pregnancy, the placenta regulates the transfer of oxygen, nutrients, and residual products between the maternal and fetal bloodstreams and is a key determinant of fetal exposure to xenobiotics from the mother. To study the disposition of substances through the placenta, various experimental models are used, especially the perfused placenta, placental villi explants, and cell lineage models. In this context, nanotechnology, an area of study that is on the rise, enables the creation of particles on nanometric scales capable of releasing drugs aimed at specific tissues. An important reason for furthering the studies on transplacental transfer is to explore the potential of nanoparticles (NPs), in new delivery strategies for drugs that are specifically aimed at the mother, the placenta, or the fetus and that involve less toxicity. Due to the fact that the placental barrier is essential for the interaction between the maternal and fetal organisms as well as the possibility of NPs being used in the treatment of various pathologies, the aim of this review is to present the main experimental models used in studying the maternal–fetal interaction and the action of NPs in the placental environment.     

Evidence for opiate receptor binding in rat small intestine

The influence of ethanol consumption during pregnancy on maternal-fetal transfer of amino acid was studied. Pregnant rats were fed a liquid diet containing 30% ethanol-derived calories from gestation-day 6 to 21; control rats were pair-fed identical diets, except that sucrose substituted isocalorically for ethanol. On gestation-day 21, 2 uCi/100 g body weight of ¹⁴C-alpha-aminoisobutyric acid (¹⁴C-AIB) was injected into the maternal circulation, and 90 minutes later maternal blood and liver, placentas and fetuses were removed for radioactivity measurement. No differences between ethanol-fed and control rats in the distribution of ¹⁴C-AIB in maternal plasma or the uptake of ¹⁴C-AIB by the maternal liver were observed. However, the radioactivities in placenta and fetal tissues suffered a significant 20 to 40% reduction in the ethanol-fed group, suggesting that ethanol feeding during pregnancy impairs placental function.     

Polyamines and diamine oxidase activity in maternal, embryonal, and fetal tissues of rat after chronic ethanol consumption

The effects of maternal ethanol consumption for 4 weeks before and throughout gestation on polyamine content and diamine oxidase activity of maternal, embryonal and fetal tissues are reported. At the 12th day of pregnancy, a decrease of putrescine in the liver of the mother and marked increases in putrescine, cadaverine and spermidine in embryos were observed. At day 18, putrescine and cadaverine diminished in maternal liver and placenta, and no changes in amine content in fetal liver and brain were found. At day 12, diamine oxidase activity increased in maternal liver and placenta, whereas it greatly diminished in embryos. At day 18, enzyme activity decreased in maternal liver, placenta, fetal liver and brain. These results indicate that chronic ethanol ingestion induces alterations in polyamine concentrations and metabolism in growing and developing tissues during pregnancy that might contribute to the adverse effect of ethanol on conceptual development.     

Sildenafil Citrate Increases Fetal Weight in a Mouse Model of Fetal Growth Restriction with a Normal Vascular Phenotype

Fetal growth restriction (FGR) is defined as the inability of a fetus to achieve its genetic growth potential and is associated with a significantly increased risk of morbidity and mortality. Clinically, FGR is diagnosed as a fetus falling below the 5^th centile of customised growth charts. Sildenafil citrate (SC, Viagra™), a potent and selective phosphodiesterase-5 inhibitor, corrects ex vivo placental vascular dysfunction in FGR, demonstrating potential as a therapy for this condition. However, many FGR cases present without an abnormal vascular phenotype, as assessed by Doppler measures of uterine/umbilical artery blood flow velocity. Thus, we hypothesized that SC would not increase fetal growth in a mouse model of FGR, the placental-specific Igf2 knockout mouse, which has altered placental exchange capacity but normal placental blood flow. Fetal weights were increased (by 8%) in P0 mice following maternal SC treatment (0.4 mg/ml) via drinking water. There was also a trend towards increased placental weight in treated P0 mice (P = 0.056). Additionally, 75% of the P0 fetal weights were below the 5^th centile, the criterion used to define human FGR, of the non-treated WT fetal weights; this was reduced to 51% when dams were treated with SC. Umbilical artery and vein blood flow velocity measures confirmed the lack of an abnormal vascular phenotype in the P0 mouse; and were unaffected by SC treatment. ¹⁴C-methylaminoisobutyric acid transfer (measured to assess effects on placental nutrient transporter activity) per g placenta was unaffected by SC, versus untreated, though total transfer was increased, commensurate with the trend towards larger placentas in this group. These data suggest that SC may improve fetal growth even in the absence of an abnormal placental blood flow, potentially affording use in multiple sub-populations of individuals presenting with FGR.     

Na+/I− Symporter and Type 3 Iodothyronine Deiodinase Gene Expression in Amniotic Membrane and Placenta and Its Relationship to Maternal Thyroid Hormones

Placental type 3 iodothyronine deiodinase (D3) potentially protects the fetus from the elevated maternal thyroid hormones. Na⁺/I^? symporter (NIS) is a plasma membrane glycoprotein, which mediates active iodide uptake. Our objectives were to establish the distribution of NIS and D3 gene expressions in the placenta and the amniotic membrane and to investigate the relationship between placental D3 and NIS gene expressions and maternal iodine, selenium, and thyroid hormone status. Thyroid hormones, urinary iodine concentration (UIC), and selenium levels were measured in 49 healthy term pregnant women. NIS and D3 gene expressions were studied with the total mRNA RT-PCR method in tissues from maternal placenta (n?=?49), fetal placenta (n?=?9), and amniotic membrane (n?=?9). NIS and D3 gene expressions were shown in the fetal and maternal sides of the placenta and amniotic membrane. Mean blood selenium level was 66?±?26.5 μg/l, and median UIC was 143 μg/l. We could not demonstrate any statistically significant relationship of spot UIC and blood selenium with NIS and D3 expression (p?>?0.05). Positive correlations were found between NIS and thyroxine-binding globulin (TBG) (r?=?0.3, p?=?0.042) and between D3 and preoperative glucose levels (r?=?0.4, p?=?0.006). D3 and NIS genes are expressed in term placenta and amniotic membrane; thus, in addition to placenta, amniotic membrane contributes to regulation of maternofetal iodine and thyroid hormone transmission. Further studies are needed to clarify the relationship between maternal glucose levels and placental D3 expression and between TBG and placental NIS expression.     

Tissue-Specific and Minor Inter-Individual Variation in Imprinting of IGF2R Is a Common Feature of Bos taurus Concepti and Not Correlated with Fetal Weight

The insulin-like growth factor 2 receptor (IGF2R) is essential for prenatal growth regulation and shows gene dosage effects on fetal weight that can be affected by in-vitro embryo culture. Imprinted maternal expression of murine Igf2r is well documented for all fetal tissues excluding brain, but polymorphic imprinting and biallelic expression were reported for IGF2R in human. These differences have been attributed to evolutionary changes correlated with specific reproductive strategies. However, data from species suitable for testing this hypothesis are lacking. The domestic cow (Bos taurus) carries a single conceptus with a similar gestation length as human. We identified 12 heterozygous concepti informative for imprinting studies among 68 Bos taurus fetuses at Day 80 of gestation (28% term) and found predominantly maternal IGF2R expression in all fetal tissues but brain, which escapes imprinting. Inter-individual variation in allelic expression bias, i.e. expression of the repressed paternal allele relative to the maternal allele, ranged from 4.6−8.9% in heart, 4.3−10.2% in kidney, 6.1−11.2% in liver, 4.6−15.8% in lung and 3.2−12.2% in skeletal muscle. Allelic bias for mesodermal tissues (heart, skeletal muscle) differed significantly (P<0.05) from endodermal tissues (liver, lung). The placenta showed partial imprinting with allelic bias of 22.9−34.7% and differed significantly (P<0.001) from all other tissues. Four informative fetuses were generated by in-vitro fertilization (IVF) with embryo culture and two individuals displayed fetal overgrowth. However, there was no evidence for changes in imprinting or DNA methylation after IVF, or correlations between allelic bias and fetal weight. In conclusion, imprinting of Bos taurus IGF2R is similar to mouse except in placenta, which could indicate an effect of reproductive strategy. Common minor inter-individual variation in allelic bias and absence of imprinting abnormalities in IVF fetuses suggest changes in IGF2R expression in overgrown fetuses could be modulated through other mechanisms than changes in imprinting.     

Controlled biosynthesis of AgCl nanoparticles by a thermotolerant <Emphasis Type="Italic">Aspergillus terreus</Emphasis> in the L-Tryptophan supplemented media: Characterization and antimicrobial activity

A simple and green method was developed for the extracellular biosynthesis of silver chloride nanoparticles, free from silver nanoparticles, using cell-free filtrate of a thermotolerant fungal strain Aspergillus terreus 8. The synthesized silver chloride nanoparticles exhibited characteristic absorption maximum at 275 nm. As-fabricated AgCl-NPs were characterized by UV-vis spectroscopy, XRD, SEM-EDX, and FT-IR. The biosynthesized silver chloride nanoparticles exhibited strong antimicrobial activity towards pathogenic microorganisms such as Fusarium oxysporum f. sp. vasinfectum and Verticillium dahliae. The synthesized silver chloride nanoparticles can be exploited as a promising new biocide bionanocomposite against pathogenic microorganisms.     

Abnormal Pregnancy Outcomes in Mice Using an Induced Periodontitis Model and the Haematogenous Migration of Fusobacterium nucleatum Sub-Species to the Murine Placenta

Objectives

To investigate if there is subspecies specific migration to the placenta by Fusobacterium nucleatum (Fn) and to determine whether experimentally induced periodontitis results in adverse pregnancy outcomes (APO) in mice.

Methods

Periodontitis was induced in pregnant mice using an inoculum of Fn and Porphyromonas gingivalis. In parallel, four sub-species of Fn were individually injected into the circulatory system. At day 18 of gestation, the placenta, liver, spleen and blood were harvested and litter size, number of viable fetuses and resorptions, maternal, fetal and placenta weights were recorded. For the direct inoculation group, some mice were allowed to deliver for assessment of length of gestation, litter size, maternal, placental and pup weight. The presence of Fn was assessed by PCR and inflammatory mediators were measured by ELISA or multiplex analysis.

Results

Mice with alveolar bone loss, a marker of periodontitis, demonstrated significantly higher fetal weights (p = 0.015) and fetal/placental weight ratios (p = 0.030). PCR analysis of maternal organs did not identify Fn in any extracted tissues. In mice that received direct injection of Fn subspecies, varying degrees of APO were observed including preterm birth, intrauterine growth restriction, and fetal loss. Haematogenous spread of only Fn subsp. nucleatum to the placenta was confirmed. Litter size was significantly smaller (p = 0.023) and the number of resorptions was higher in inoculated versus control groups. Mice injected with subsp. nucleatum had significantly increased circulating CRP levels (p = 0.020) compared to controls while the mice with induced periodontitis had increased levels of IL-6 (p = 0.047) and IL-8 (p = 0.105).

Conclusions

Periodontitis in mice elevated fetal weight and the fetal weight/placental weight ratio. This study found that subsp. nucleatum migrated haematogenously to the placenta, leading to APO in mice. The study supports the potential role of Fn in the association between periodontitis and APO.     

Placental Glucose Transfer: A Human In Vivo Study

ObjectivesThe placental transfer of nutrients is influenced by maternal metabolic state, placenta function and fetal demands. Human in vivo studies of this interplay are scarce and challenging. We aimed to establish a method to study placental nutrient transfer in humans. Focusing on glucose, we tested a hypothesis that maternal glucose concentrations and uteroplacental arterio-venous difference (reflecting maternal supply) determines the fetal venous-arterial glucose difference (reflecting fetal consumption).MethodsCross-sectional in vivo study of 40 healthy women with uncomplicated term pregnancies undergoing planned caesarean section. Glucose and insulin were measured in plasma from maternal and fetal sides of the placenta, at the incoming (radial artery and umbilical vein) and outgoing vessels (uterine vein and umbilical artery).ResultsThere were significant mean (SD) uteroplacental arterio-venous 0.29 (0.23) mmol/L and fetal venous-arterial 0.38 (0.31) mmol/L glucose differences. The transplacental maternal-fetal glucose gradient was 1.22 (0.42) mmol/L. The maternal arterial glucose concentration was correlated to the fetal venous glucose concentration (r = 0.86, p<0.001), but not to the fetal venous-arterial glucose difference. The uteroplacental arterio-venous glucose difference was neither correlated to the level of glucose in the umbilical vein, nor fetal venous-arterial glucose difference. The maternal-fetal gradient was correlated to fetal venous-arterial glucose difference (r = 0.8, p<0.001) and the glucose concentration in the umbilical artery (r = −0.45, p = 0.004). Glucose and insulin concentrations were correlated in the mother (r = 0.52, p = 0.001), but not significantly in the fetus. We found no significant correlation between maternal and fetal insulin values.ConclusionsWe did not find a relation between indicators of maternal glucose supply and the fetal venous-arterial glucose difference. Our findings indicate that the maternal-fetal glucose gradient is significantly influenced by the fetal venous-arterial difference and not merely dependent on maternal glucose concentration or the arterio-venous difference on the maternal side of the placenta.     

Feto-maternal production and transfer of cortisol in the rhesus (Macaca mulatta)

Four pregnant rhesus monkeys cnd their fetuses. were infused constantly with ¹⁴C-cortisol and ³H-cortisol. Steady state plasma specific activities for ¹⁴C and ³H-cortisol were obtained after 80 to 90 minutes in both mother and fetus. These data and the rates of infusion of radioactivity were used to calculate the following parameters for both mother and fetus: 1) metabolic clearance rates, 2) production rates, 3) mean adrenal secretory rates, 4) transfer rates from mother to fetus and fetus to mother cnd, 5) the fraction of cortisol in each vascular compartment derived from the maternal and fetal edrenals. Plasma cortisone concentrations, as well as the fraction of cortisone derived from fetal and maternal cortisol were determined. Tetrahydrocortisol and tetrahydrocortisone concentrations were calculated. Mean cortisol secretory rates for the maternal and fetal adrenals were 60.0±11.8 and 1.82±0.42 mg/day. Fifty-eight % of the cortisol in the fetal compartment was of maternal origin. During transfer across the placenta to the fetus, cortisol was largely converted to cortisone. In fetal plasma 76% of the cortisone was of maternal origin. Cortisone concentrations in fetal plasma were higher than those of cortisol.     

Effects of an antisense oligonucleotide inhibitor of human ICAM-1 on fetal development in rabbits

The potential for reproductive toxicity of an antisense oligonucleotide designed to inhibit ICAM-1 was evaluated as part of the safety assessment for this compound. The human active ICAM-1 inhibitor (ISIS 2302) is not pharmacologically active in rabbits. Female rabbits were treated once daily on Day 6 through 18 of gestation. Rabbits were treated with 0, 1, 3, and 9 mg/kg ISIS 2302 by daily i.v. injection. Reproductive indices evaluated included estrus cycling, litter parameters, fetal development, and fetal body weight. Concentrations of oligonucleotide in plasma following the last dose, and in selected maternal target organs, placenta, and fetal tissues at scheduled necropsy were also measured. Maternal toxicity was evident as a decreased maternal body weight gain, decreased food consumption, and scant feces at doses > or =3 mg/kg. Increased spleen to body weight ratio and increased mononuclear cell infiltrates were indicative of a proinflammatory effect of ISIS 2302 at the 9 mg/kg dose level. Despite the maternal toxicity, there were no changes in litter parameters or fetal development in rabbits treated with ISIS 2302. The only change was a decrease in fetal body weight at the 9 mg/kg dose level, which was attributed to the maternal toxicity observed. Maternal liver and kidney contained dose-dependent concentrations of oligonucleotide, but there was relatively little or no oligonucleotide measured in placenta or fetal tissues. Thus, there was no dose-dependent exposure and maternal toxicity to ISIS 2302, but no reproductive toxicity in rabbits, and exposure of fetus or pups is negligible.     

Scanning electron microscopy of the placental interface in the viviparous lizard Sceloporus jarrovi (Squamata: Phrynosomatidae)

Placental membranes mediate maternal‐fetal exchange in all viviparous reptilian sauropsids. We used scanning electron microscopy to examine the placental interface in the mountain spiny lizard, Sceloporus jarrovi (Phrynosomatidae). From the late limb bud stage until birth, the conceptus is surrounded by placental membranes formed from the chorioallantois and yolk sac omphalopleure. The chorioallantois lies directly apposed to the uterine lining with no intervening shell membrane. Both fetal and maternal sides of the chorioallantoic placenta are lined by continuous layers of flattened epithelial cells that overlie dense capillary networks. The chorioallantoic placenta shows specializations that enhance respiratory exchange, as well as ultrastructural evidence of maternal secretion and fetal absorption. The yolk sac placenta contains enlarged fetal and maternal epithelia with specializations for histotrophic nutrient transfer. This placenta lacks intrinsic vascularity, although the vascular allantois lies against its inner face, contributing to an omphallantoic placenta. In a specialized region at the abembryonic pole, uterine and fetal tissues are separated by a compact mass of shed shell membrane, yolk droplets, and cellular debris. The omphalopleure in this region develops elongate folds that may contribute to sequestration and absorption of this material. Fetal membrane morphogenesis and composition in S. jarrovi are consistent with those of typical squamates. However, this species exhibits unusual placental specializations characteristic of highly placentotrophic lizards. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc.     

Preliminary results of the placental decorin profile in bovine pregnancy and parturition

Decorin is a small leucine-rich proteoglycan which is involved in multiple biological functions mainly as a structural and signaling molecule. Due to its biological properties in connective tissue, decorin may participate in remodeling of ECM during attachment and detachment of placenta within the course of pregnancy and at parturition in cows. The aim of the study was to detect the presence of decorin protein in bovine placental tissues and to evaluate its profile during pregnancy and at parturition. Placental tissues from healthy pregnant cows (2–5 month) were collected in abattoir (n?=?10), while parturient tissues were obtained during caesarian section at physiological term (n?=?6). Maternal and fetal parts were separated manually and subjected to homogenization and to quantitative ELISA and verification by Western blotting with anti-decorin antibodies. ELISA test showed that the concentration of decorin during pregnancy was higher in the fetal part of placenta compared with the maternal part (p?<?0.001). Similar pattern was noted regarding to maternal and fetal samples derived from parturient cows. Our preliminary results demonstrate that the concentration of decorin is gestation time-dependent in healthy bovine placenta. Possible confirmation of the involvement of decorin in early pregnancy attachment and detachment of the placenta during parturition requires further research.     

Effects of methyl-deficient diets on methionine and homocysteine metabolism in the pregnant rat

Although the importance of methyl metabolism in fetal development is well recognized, there is limited information on the dynamics of methionine flow through maternal and fetal tissues and on how this is related to circulating total homocysteine concentrations. Rates of homocysteine remethylation in maternal and fetal tissues on days 11, 19, and 21 of gestation were measured in pregnant rats fed diets with limiting or surplus amounts of folic acid and choline at two levels of methionine and then infused with L-[1-(13)C,(2)H(3)-methyl]methionine. The rate of homocysteine remethylation was highest in maternal liver and declined as gestation progressed. Diets deficient in folic acid and choline reduced the production of methionine from homocysteine in maternal liver only in the animals fed a methionine-limited diet. Throughout gestation, the pancreas exported homocysteine for methylation within other tissues. Little or no methionine cycle activity was detected in the placenta at days 19 and 21 of gestation, but, during this period, fetal tissues, especially the liver, synthesized methionine from homocysteine. Greater enrichment of homocysteine in maternal plasma than placenta, even in animals fed the most-deficient diets, shows that the placenta did not contribute homocysteine to maternal plasma. Methionine synthesis from homocysteine in fetal tissues was maintained or increased when the dams were fed folate- and choline-deficient methionine-restricted diets. This study shows that methyl-deficient diets decrease the remethylation of homocysteine within maternal tissues but that these rates are protected to some extent within fetal tissues.     

The effect of pregnancy on production of maternal endogenous hematopoietic stem cells

Fetal microchimerism refers to the presence of fetal cells in maternal blood and tissues during pregnancy. This microchimerism may result from trafficking of fetal and maternal blood across the placenta during pregnancy. Physiological changes in the maternal blood cellular milieu are also recognized during pregnancy and in the early postpartum period. Earlier studies showed that maternal blood contains CD34⁺ hematopoietic stem cells (HSCs) that bear paternal genetic markers or male phenotype, suggesting that these cells circulated to the mother from male fetuses during pregnancy. Other studies showed that these maternal HSCs have significantly lower expansion potential than their fetal counterparts. We have recently shown increased percentages of CD34⁺ HSCs in peripheral blood of pregnant and parous women. Herein, we hypothesize that pregnancy stimulates the production of endogenous CD34⁺ HSCs of maternal origin, a phenomenon which potentially could favor postpartum regenerative capacity.     

Gestational losses in a rabbit line selected for growth rate

Prenatal death can occur due to several genetic and environmental factors which alter normal embryo development, maternal environment to support normal fertilisation, development of embryos, placenta and foetus, or affect the necessary relationship between embryo and endometrium. The aim of this work was to study gestational losses and progesterone, 17 β-estradiol and IGF I serum levels in a rabbit line selected for growth rate (paternal line). In this study, a maternal line well characterised in previous studies was used as a reference line. A total of 211 laparoscopies were carried out, and the number of corpora lutea and implanted embryos at 12^th days, total born and live born were recorded per female. To analyse the endocrine levels, blood serum was collected from 54 females with implanted embryos at 12^th and 24^th day of gestation (27 from each line). The paternal line showed the lowest ovulation frequency, number of implanted embryos, total born and live born (0.70, 11.3, 7.4, and 6.4 vs 0.86, 12.8, 11.1 and 10.6 for maternal line, respectively) and consequently, the highest implantation, gestational, foetal and perinatal losses (0.31, 0.60, 0.40, and 0.15, respectively). Progesterone serum levels at 12^th days of gestation were similar between lines; however, progesterone serum level at 24^th day of gestation was significantly lower in the paternal line (4.8 vs 8.2 ng/mL). Serum levels of 17β-estradiol and IGF-I at 12^th days of gestation were different between lines (14.6 vs 26.5 pg/mL, 237 vs 149 ng/mL for paternal and maternal lines respectively). These higher gestational losses of the paternal line could be explained by differences in 17 β-estradiol level at 12^th days of gestation and the possible effect on low progesterone serum levels at 24^th days of gestation. Further studies in steroid production and bioavailability have to be done during oestrus and pregnancy related with metabolic activity of this line.