Inhibition of VEGF-A expression in hypoxia-exposed fetal retinal microvascular endothelial cells by exosomes derived from human umbilical cord mesenchymal stem cells

Objective:This study aimed to investigate the potential of human umbilical cord mesenchymal stem cell(hucMSC)-derived exosomes(hucMSC-Exos)in inhibiting hypoxia-induced cell hyper proliferation and overexpression of vascular endothelial growth factor A(VEGF-A)in immature human fetal retinal microvascular endothelial cells(hfRMECs).Methods:Exosomes were isolated from hucMSCs using cryogenic ultracentrifugation and characterized through various techniques,including transmission electron microscopy,nanoparticle tracking analysis,bicinchoninic acid assays,and western blotting.The hfRMECs were identified using von Willebrand factor(vWF)co-staining and divided into four groups:a control group cultured under normoxic condition,a hypoxic model group,a hypoxic group treated with low-concentration hucMSC-Exos(75μg/mL)and a hypoxic group treated with high-concentration hucMSC-Exos(100μg/mL).Cell viability and proliferation were assessed using Cell Counting Kit-8(CCK-8)assay and EdU(5-ethynyl-2′-deoxyuridine)assay respectively.Expression levels of VEGF-A were evaluated using RT-PCR,western blotting and immunofluorescence.Results:Hypoxia significantly increased hfRMECs’viability and proliferation by upregulating VEGF-A levels.The administration of hucMSC-Exos effectively reversed this response,with the high-concentration group exhibiting greater efficacy compared to the lowconcentration group.Conclusion:In conclusion,hucMSC-Exos can dose-dependently inhibit hypoxia-induced hyperproliferation and VEGF-A overexpression in immature fetal retinal microvascular endothelial cells.

Differential Expression of APOEGene in Porcine Fetal Fibroblast Cells

[Objective]The aim was to study the differential expression ofAPOEgene in different generations of porcine fetal fibroblasts cells.[Method]The first,tenth,fifteenth,twentieth,twenty-fifth,fiftieth generations of porcine fetal fibroblast cells,which were normally grown and passed,were collected before total RNA was extracted respectively.The expression ofAPOEgene in different generations of porcine fetal fibro-blast cells was detected by RT-PCR technique.[Result]The expression level of porcine APOE mRNA in the first generation of porcine fetal fi-broblast cells was the highest,and then it gradually decreased with the increase of cell generations and was the lowest in the fiftieth generation.[Conclusion]The expression ofAPOEgene had the selective trend in different generations of porcine fetal fibroblast cells.

Hepatocytic differentiation of mesenchymal stem cells in cocultures with fetal liver cells

AIM： To investigate the hepatocytic differentiation of mesenchymal stem cells （MSCs） in co-cultures with fetal liver cells （FLC） and the possibility to expand differentiated hepatocytic cells. METHODS： MSCs were marked with green fluorescent protein （GFP） by retroviral gene transduction. Clonal marked MSCs were either cultured under liver stimulating conditions using fibronectin-coated culture dishes and medium supplemented with stem cell factor （SCF）, hepatocyte growth factor （HGF）, epidermal growth factor （EGF）, and fibroblast growth factor 4 （FGF-4） alone, or in presence of freshly isolated FLC. Cells in co-cultures were harvested, and GFP＋ or GFP- cells were separated using fluorescence activated cell sorting. Reverse transcription-polymerase chain reaction （RT-PCR） for the liver specific markers cytokeratin-18 （CK-18）, albumin, and alpha-fetoprotein （AFP） was performed in different cell populations. RESULTS- Under the specified culture conditions, rat MSCs co-cultured with FLC expressed albumin, CK-18, and AFP-RNA over two weeks. At wk 3, MSCs lost hepatocytic gene expression, probably due to overgrowth of the cocultured FLC. FLC also showed a stable liver specific gene expression in the co-cultures and a very high growth potential. CONCLUSION： The rat MSCs from bone marrow can differentiate hepatocytic cells in the presence of FLC in vitro and the presence of MSCs in co-cultures also prorides a beneficial environment for expansion and differentiation of FLC.

Gene transfer into primary cultures of fetal neural stem cells by a recombinant adenovirus carrying the gene for green fluorescent protein

Objective: To evaluate the transduction efficiency of a recombinant adenovirus carrying the gene for green fluorescent protein (Ad-GFP) into the primary cultures of fetal neural stem cells (NSCs) by the expression of GFP. Methods: The Ad-GFP was constructed by homologous recombination in bacteria with the AdEasy system; NSCs were isolated from rat fetal hippocampus and cultured as neurosphere suspensions. After infection with the recombinant Ad-GFP, NSCs were examined with a fluorescent microscopy and a flow cytometry for their expression of GFP. Results: After the viral infection, flow cytometry analysis revealed that the percentage of GFP-positive cells was as high as 97.05%. The infected NSCs sustained the GFP expression for above 4 weeks. After differentiated into astrocytes or neurons, they continued to express GFP efficiently. Conclusion: We have success- fully constructed a viral vector Ad-GFP that can efficiently infect the primary NSCs. The reporter gene was showed fully and sustained expression in the infected cells as well as their differentiated progenies.

Synaptic development in the injured spinal cord cavity following co-transplantation of fetal spinal cord cells and autologous activated Schwann cells

Transplantation of activated transgenic Schwann cells or a fetal spinal cord cell suspension has been widely used to treat spinal cord injury. However, little is known regarding the effects of co-transplantation. In the present study, autologous Schwann cells in combination with a fetal spinal cord cell suspension were transplanted into adult Wistar rats with spinal cord injury, and newly generated axonal connections were observed ultrastructurally. Transmission electron microscopic observations showed that the neuroblast first presented cytoplasmic processes, followed by pre- and postsynaptic membranes with low electron density forming a dense projection. The number and types of synaptic vesicles were increased. Synaptic connections developed from single cell body-dendritic synapses into multiple cell body-dendritic and dendrite-dendritic synapses. In addition, the cell organs of the transplanted neuroblast, oligodendroblast and astroblast matured gradually. The blood-brain barrier appeared subsequently. Moreover, neurofilament, histamine, calcitonin-gene-related peptides, and glial fibrillary acidic protein positive fibers were observed in the transplant region. These findings demonstrate that fetal spinal cord cells in the presence of autologous activated Schwann cells can develop into mature synapses in the cavity of injured spinal cords, suggesting the possibility of information exchange through the reconstructed synapse between fetal spinal cord cells and the host.

An appropriate level of autophagy reduces emulsified isoflurane-induced apoptosis in fetal neural stem cells

Autophagy plays essential roles in cell survival.However,the functions and regulation of the autophagy-related proteins Atg5,LC3B,and Beclin 1 during anesthetic-induced developmental neurotoxicity remain unclear.This study aimed to understand the autophagy pathways and mechanisms that affect neurotoxicity,induced by the anesthetic emulsified isoflurane,in rat fetal neural stem cells.Fetal neural stem cells were cultured,in vitro,and neurotoxicity was induced by emulsified isoflurane treatment.The effects of pretreatment with the autophagy inhibitors 3-methyladenine and bafilomycin and the effects of transfection with small interfering RNA against ATG5(siRNA-Atg5)were observed.Cell viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay,and apoptosis was assessed using flow cytometry.Ultrastructural changes were analyzed through transmission electron microscopy.The levels of the autophagy-related proteins LC3B,Beclin 1,Atg5,and P62 and the pro-apoptosis-related protein caspase-3 were analyzed using western blot assay.The inhibition of cell proliferation and that of apoptosis rate increased after treatment with emulsified isoflurane.Autophagolysosomes,monolayer membrane formation due to lysosomal degradation,were observed.The autophagy-related proteins LC3B,Beclin 1,Atg5,and P62 and caspase-3 were upregulated.These results confirm that emulsified isoflurane can induce toxicity and autophagy in fetal neural stem cells.Pre-treatment with 3-methyladenine and bafilomycin increased the apoptosis rate in emulsified isoflurane-treated fetal neural stem cells,which indicated that the complete inhibition of autophagy does not alleviate emulsified isoflurane-induced fetal neural stem cell toxicity.Atg5 expression was decreased significantly by siRNA-Atg5 transfection,and cell proliferation was inhibited.These results verify that the Atg5 autophagy pathway can be regulated to maintain appropriate levels of autophagy,which can inhibit the neurotoxicity induced by emulsified isoflurane anesthetic in fetal neural stem cells.

The Potential of Rat Inner Cell Mass and Fetal Neural Stem Cells to Generate Chimeras

The rat chimera is an important animal model for the study of complex human diseases. In the present study we evaluated the chimeric potential of rat inner cell masses （ICMs） and fetal neural stem （FNS） cells. In result, three rat chimeras were produced by day 5 （D5） Sprague-Dawley （SD） blastocysts injected with ICMs derived from day 6 （D6） and D5 Dark Agouti （DA） blastocysts; four rat chimeras had been generated by D5 DA blastocyst injected with D5 SD ICMs. For the requirement of gene modification, cultured rat inner cell mass cells were assessed to produce chimeras, but no chimeras were generated from injected embryos. The potential to generate chimeras from rFNS and transfected rFNS cells were tested, but no chimeric pups were produced. Only 2 of 41 fetuses derived from D5 DA blastocyst injection with SD LacZ transfected rFNS cells showed very low number of LacZ positive cells in the section. These results indicate that DA and SD rat ICMs arc able to contribute to chimeras, but their potential decreases significantly after culture in vitro （P〈0.05）, and rFNS cells only have the potential to contribute to early fetal development.

Enrichment of Fetal Nucleated Red Blood Cells by Multi-core Magnetic Composite Particles for Non-invasive Prenatal Diagnosis

A novel kind of multi-core magnetic composite particles, the surfaces of which were respectively mo- dified with goat-anti-mouse IgG and antitransferrin receptor（anti-CD71）, was prepared. The fetal nucleated red blood cells（FNRBCs） in the peripheral blood of a gravida were rapidly and effectively enriched and separated by the mo- dified multi-core magnetic composite particles in an external magnetic field. The obtained FNRBCs were used for the identification of the fetal sex by means of fluorescence in situ hybridization（FISH） technique. The results demonstrate that the multi-core magnetic composite particles meet the requirements for the enrichment and speration of FNRBCs with a low concentration and the accuracy of detetion for the diagnosis of fetal sex reached to 95%. Moreover, the obtained FNRBCs were applied to the non-invasive diagnosis of Down syndrome and chromosome 3p21 was de- tected. The above facts indicate that the novel multi-core magnetic composite particles-based method is simple, relia- ble and cost-effective and has opened up vast vistas for the potential application in clinic non-invasive prenatal diag- nosis.

Are there fetal stem cells in the maternal brain?

Fetal cells can enter maternal blood during pregnancy but whether they can also cross the blood-brain barrier to enter the maternal brain remains poorly understood. Previous results suggest that fetal cells are summoned to repair damage to the mother＇s brain. If this is confirmed, it would open up new and safer avenues of treatment for brain damage caused by strokes and neural diseases. In this study, we aimed to investigate whether a baby＇s stem cells can enter the maternal brain during pregnancy. Deceased patients who had at least one male offspring and no history of abortion and blood transfusion were included in this study. DNA was extracted from brain tissue samples of deceased women using standard phenol-chloroform extraction and ethanol precipitation methods. Genomic DNA was screened by quantitative fluorescent-polymerase chain reaction amplification together with short tandem repeat markers specific to the Y chromosome, and 13, 18, 21 and X. Any foreign DNA residues that could be used to interpret the presence of fetal stem cells in the maternal brain were monitored. Results indicated that fetal stem cells can not cross the blood-brain barrier to enter the maternal brain.

Stem cells for spine surgery

In the past few years, stem cells have become the focus of research by regenerative medicine professionals and tissue engineers. Embryonic stem cells, although capable of differentiating into cell lineages of all three germ layers, are limited in their utilization due to ethical issues. In contrast, the autologous harvest and subsequent transplantation of adult stem cells from bone marrow, adipose tissue or blood have been experimentally utilized in the treatment of a wide variety of diseases ranging from myocardial infarction to Alzheimer's disease. The physiologic consequences of stem cell transplantation and its impact on functional recovery have been studied in countless animal models and select clinical trials. Unfortunately, the bench to bedside translation of this research has been slow. Nonetheless, stem cell therapy has received the attention of spinal surgeons due to its potential benefits in the treatment of neural damage, muscle trauma, disk degeneration and its potential contribution to bone fusion.

REGULATORY EFFECTS OF HUMAN RECOMBINANT IL-6 ON NATURAL KILLER CELL ACTIVITY OF HUMAN FETAL SPLEENS

In the present study it was proved first that human recombinant interleukin-6(HrIL-6) significantly augmented natural killer(NK) cell activity derived from human fetal spleens against K562 target cells in a 4 hours 51Cr release assay. The enhancement of NK activity with 24 hours preincubation in HrlL-6 was dose-dependent, and significantly higher than that of fresh NK cells and controls cultured with RPMI-1640 medium alone (P<0.001). We also found that IL-6 was able to augment NK activity from different fetal spleens at 20 to 40 weeks of gestation (up to 2.24 to 2.78 times), and no difference of NK activity of fetal splenocytes treated by HrIL-6 was observed between different fetal age (32.3% to 45.4%, P>0.05). Furthermore, IL-6-augmented NK activity of fetal splenocytes was very similar to adult levels (P>0.05). These finding strongly indicated that IL-6 plays an important role in the development of NK cell function during the gestational period, suggesting that IL-6 may be of importance in the regulation of host defense mechanisms against malignancies and viral diseases.

Chimera formation of platelet GPⅡb Bak a/b by intrauterine transplantation of fetal liver stem cells

Abstract:Objective To investigate whether artificial heterozygous chimeras of platelets can be established by intrauterine transplantation of fetal liver stem cells and evaluate its potential use for the treatment of Glanzmann thrombasthenia.Methods Platelet glycoprotein (GP) Ⅱb Bak a/b (or GPⅡb Ⅰle843Ser) was used as a genetic marker. A homozygous 16-week-old Bak a/a fetus (as donor) and a homozygous 16.5-week-old Bak b/b fetus (as recipient) were screened from 42 pregnant women hospitalized for abortion. PCR with allele specific primers and FOK Ⅰ digestion based on PCR products were used. Aborted donor fetal liver cell suspensions were prepared and intrauterine transplantation was carried out by infusion of 4?ml fetal liver cells (22×105) into the recipient umbilical vein under ultrasonic visualization.Results At gestation termination (abortion), 21 days after transplantation, chimera GPⅡb Bak a/b of the recipient were detected by FOK 1 digestion based on PCR from DNA and RT-PCR from platelet RNA. Conclusion Intrauterine transplantation of fetal liver cell may provide an effective way for curing GT or other inherited diseases.

An Eperimental Study on the Transplantation of Human Fetal Brain Cells into Monkey Models of Parkinson's Disease.

Unilateral administration of methly-phenyl-tetrahydropyridine(MPTP) into the common carotid artery

Chondrogenic priming of human fetal synovium-derived stem cells in an adult stem cell matrix microenvironment

Cartilage defects are a challenge to treat clinically due to the avascular nature of cartilage.Low immunogenicity and extensive proliferation and multidifferentiation potential make fetal stem cells a promising source for regenerative medicine.In this study,we aimed to determine whether fetal synovium-derived stem cells(FSDSCs)exhibited replicative senescence and whether expansion on decellularized extracellular matrix(dECM)deposited by adult SDSCs(AECM)promoted FSDSCs’chondrogenic potential.FSDSCs from passage 2 and 9 were compared for chondrogenic potential,using Alcian blue staining for sulfated glycosaminoglycans(GAGs),biochemical analysis for DNA and GAG amounts,and real-time PCR for chondrogenic genes including ACAN and COL2A1.Passage 3 FSDSCs were expanded for one passage on plastic flasks(PL),AECM,or dECM deposited by fetal SDSCs(FECM).During expansion,cell proliferation was evaluated using flow cytometry for proliferation index,stem cell surface markers,and resistance to hydrogen peroxide.During chondrogenic induction,expanded FSDSCs were evaluated for tri-lineage differentiation capacity.We found that cell expansion enhanced FSDSCs’chondrogenic potential at least up to passage 9.Expansion on dECMs promoted FSDSCs’proliferative and survival capacity and adipogenic differentiation but not osteogenic capacity.AECM-primed FSDSCs exhibited an enhanced chondrogenic potential.

INTRACEREBRAL CO-GRAFTING OF SCHW ANN'S CELLS AND FETAL ADRENAL MEDULLA IN THE TREATMENT OF PARKINSON'S DISEASE

Intracerebral co-grafting of Schwann's cells and human fetal adrenal medullary tissue was performed in 10 patients with Parkinson's disease. One to six months after grafting, symptoms were improved significantly for 1 to 3 grade. Among them, 2 patients resumed nearly normal daily activities. Long-term follow-up showed that the symptoms were not improved satisfactorily in some patients. It is considered that careful selection of patients, administration of amantadine, and co-grafting of Schwann's cells which prompts the survival of chromaffin cells are essential to better results.

Amniocentesis: A contemporary review

Amniocentesis is an essential tool in obstetrics. Invasive testing remains the only modality for diagnostic genetic testing and the only way to provide comprehensive test-ing for chromosomal abnormalities. Despite increasing use of cell free fetal deoxyribonucleic acid （DNA） testing, amniocentesis should still be offered to all women who desire more complete and accurate genetic testing. Counseling patients on the limitations of screening tests is of the upmost importance and amniocentesis should continue to be recommended to confrm positive results from cell free fetal DNA testing or in the case of failed cell free fetal DNA test. As cell free fetal DNA screening has not adequately been studied in multiple gestations, its use is not recommended in this population and invasive testing should be offered. Amniocentesis is also very useful in providing additional information in settings other than genetic testing the second and third trimester. If intraamniotic infection is suspected, but the clinical fndings are not enough to guide manage-ment, amniocentesis can provide testing that can both immediately clarify the picture （interleukin-6, gram stain, glucose levels） and finally confirm the presence of infection （culture）. It can also be used to detect the presence of intrauterine viral infections. Additionally, amniocentesis may be used to test for markers of fetal lung maturity. The American Congress of Obstetricians and Gynecologists recommends that amniocentesis for this indication not be used in cases where late preterm delivery is indicated. It may be useful in guiding decision-making, however , when late preterm delivery is indicated, but when exact timing is unclear. Regardless of the indication, amniocentesis appears to be a relatively low risk procedure with minimal risk to the patient. Additional randomized controlled trials are not likely, as they are not feasible to due extremely high number of participants that would be needed to detect a difference in loss rates. Based on current literature, however, the risk of pregnancy loss from second trime-ster amniocentesis is low in both singleton and twin gestations. We counsel patients that technique has changed since the original studies in the 1970s and feel comfortable quoting a loss rate of 1/500-1/1000 based on contemporary data.

Differentiated cells derived from fetal neural stem cells improve motor deficits in a rat model of Parkinson's disease

Objective: Parkinson's disease(PD), which is one of the most common neuro‐degenerative disorders, is characterized by the loss of dopamine(DA) neurons in the substantia nigra in the midbrain. Experimental and clinical studies have shown that fetal neural stem cells(NSCs) have therapeutic effects in neurological disorders. The aim of this study was to examine whether cells that were differentiated from NSCs had therapeutic effects in a rat model of PD. Methods: NSCs were isolated from 14‐week‐old embryos and induced to differentiate into neurons, DA neurons, and glial cells, and these cells were characterized by their expression of the following markers: βⅢ‐tubulin and microtubule‐associated protein 2(neurons), tyrosine hydroxylase(DA neurons), and glial fibrillary acidic protein(glial cells). After a 6‐hydroxydopamine(6‐OHDA)‐lesioned rat model of PD was generated, the differentiated cells were transplanted into the striata of the 6‐OHDA‐lesioned PD rats. Results: The motor behaviors of the PD rats were assessed by the number of apomorphine‐induced rotation turns. The results showed that the NSCs differentiated in vitro into neurons and DA neurons with high efficiencies. After transplantation into the striata of the PD rats, the differentiated cells significantly improved the motor deficits of the transplanted PD rats compared to those of the control nontransplanted PD rats by decreasing the apomorphine‐induced turn cycles as early as 4 weeks after transplantation. Immunofluorescence analyses showed that the differentiated DA neurons survived more than 16 weeks. Conclusions: Our results showed that cells that were differentiated from NSCs had therapeutic effects in a rat PD model, which suggests that differentiated cells may be an effective treatment for patients with PD.

Fate determination of fetal Leydig cells

Leydig cell(LC)is one of the most important somatic cell types in testis,which localized in the interstitium between seminiferous tubules.The major function of Leydig cells is to produce steroid hormone,androgens.LC differentiation exhibits a biphasic pattern in rodent testes,which are divided into two different temporal mature populations,fetal Leydig cells(FLCs)and adult Leydig cells(ALCs).FLCs are transiently present in fetal testes and undergo involution or degeneration after birth.FLCs are completely devoid and replaced by ALCs in adult testes.Comparing to ALCs,FLCs display unique morphology,ultrastructure and functions.The origin of FLCs has been debated for many years,but it is still a mystery.Many factors have been reported regulating the specification,proliferation and differentiation of FLCs.FLCs degenerate in a few weeks postnatally,however,the underlying mechanism is still unknown.In this review,we will focus on the fate determination of FLCs,and summarize the resent progress on the morphology,ultrastructure,function,origin and involution of FLCs.

EFFECTS OF DAURISOLINE ON CYTOSOLIC FREE CALCIUMIN FETAL RAT CEREBRAL CELLS

Cytosolic free Ca([Ca]i)was measured in dissociated cerebral cells isolated from fetal rats with the fluorescent indicater fura-2. Increase in[Ca]i occurred rapidly following explsure of the cells to 50 mmol/L KCI,10mol/L Bayk 8644 or 200μmol/L glutamate（Glu）.[Ca]i elevated by

ALP Induction by β－glycerophosphate during the Nonmineralization Phase In Vitro

β-GP influences on rat osteoblast development at the early period of culture i.e , the non-mineralization phase, and changes with the different cell passages were investigated. Alkaline phosphatase (ALP) was chosen as a main object. Northern blot analysis revealed up to two-fold increase in the steady statelevel of ALP mRNA after stimulation of rat osteoblast with 10 mM β-GP- Likewise, 10 mM β-GP induced a 10─30 % increase in ALP activity (P< 0. 01) of early passages (1 to 4), but not of later passages (5 to 6). The β-GP induced increase in ALP activity was totally inhibited by the protein synthesis inhibitor, cycloheximide (50 μM).β- GP stimulation was found to be without effect on cell proliferation measured as 3H-thymidine incorporation. It is concluded that β-GP has no effect on proliferation but induces an increase in both mRNA level and activity of ALP in the non-mineralization phase of cultures of fetal rat calvarial cells , which lasts for several passages but will disappear in older cultures.