Cell-free synthetic biology: an emerging strategy torevolutionize the biomedical industry / 生物工程学报

Cell-free synthetic biology system can perform biological transcription and translation process in vitro. Because of its advanced features, such as flexible openness, easy control, short expression time and high tolerance to cytotoxicity, this systemhas been successfully used to synthesize proteins that are difficult to express in cells. With the continuous development of cell-free biosensing technology and the lyophilization technology, its applications have widely expanded into many biomedical fields. This review discusses the current research progress of cell-free synthetic biology system in on-demand biopharmaceutical synthesis, portable diagnostics, and others. Further development of the system can lead to even more complicated synthesis of therapeutic proteins with post-translational modifications and evolution of different cell-free biosensors with high sensitivity. Cell-free synthetic biology as an emerging engineering strategy can be a better means applied to high-throughput screening of pharmaceutical proteins, detection of new pathogens, and other important health-care fields in the future.

Neuroprotective mechanisms of dieckol against glutamate toxicity through reactive oxygen species scavenging and nuclear factor-like 2/heme oxygenase-1 pathway

Glutamate toxicity-mediated mitochondrial dysfunction and neuronal cell death are involved in the pathogenesis of several neurodegenerative diseases as well as acute brain ischemia/stroke. In this study, we investigated the neuroprotective mechanism of dieckol (DEK), one of the phlorotannins isolated from the marine brown alga Ecklonia cava, against glutamate toxicity. Primary cortical neurons (100 µM, 24 h) and HT22 neurons (5 mM, 12 h) were stimulated with glutamate to induce glutamate toxic condition. The results demonstrated that DEK treatment significantly increased cell viability in a dose-dependent manner (1–50 µM) and recovered morphological deterioration in glutamate-stimulated neurons. In addition, DEK strongly attenuated intracellular reactive oxygen species (ROS) levels, mitochondrial overload of Ca²⁺ and ROS, mitochondrial membrane potential (ΔΨ(m)) disruption, adenine triphosphate depletion. DEK showed free radical scavenging activity in the cell-free system. Furthermore, DEK enhanced protein expression of heme oxygenase-1 (HO-1), an important anti-oxidant enzyme, via the nuclear translocation of nuclear factor-like 2 (Nrf2). Taken together, we conclude that DEK exerts neuroprotective activities against glutamate toxicity through its direct free radical scavenging property and the Nrf-2/HO-1 pathway activation.

Anti-Proliferative Activities of Vasicinone on Lung Carcinoma Cells Mediated via Activation of Both Mitochondria-Dependent and Independent Pathways

Vasicinone, a quinazoline alkaloid from Adhatoda vasica Nees. is well known for its bronchodilator activity. However its antiproliferative activities is yet to be elucidated. Here-in we investigated the anti-proliferative effect of vasicinone and its underlying mechanism against A549 lung carcinoma cells. The A549 cells upon treatment with various doses of vasicinone (10, 30, 50, 70 µM) for 72 h showed significant decrease in cell viability. Vasicinone treatment also showed DNA fragmentation, LDH leakage, and disruption of mitochondrial potential, and lower wound healing ability in A549 cells. The Annexin V/PI staining showed disrupted plasma membrane integrity and permeability of PI in treated cells. Moreover vasicinone treatment also lead to down regulation of Bcl-2, Fas death receptor and up regulation of PARP, BAD and cytochrome c, suggesting the anti-proliferative nature of vasicinone which mediated apoptosis through both Fas death receptors as well as Bcl-2 regulated signaling. Furthermore, our preliminary studies with vasicinone treatment also showed to lower the ROS levels in A549 cells and have potential free radical scavenging (DPPH, Hydroxyl) activity and ferric reducing power in cell free systems. Thus combining all, vasicinone may be used to develop a new therapeutic agent against oxidative stress induced lung cancer.

Aminotransferase and glutamate dehydrogenase activities in lactobacilli and streptococci

ABSTRACT Aminotransferases and glutamate dehydrogenase are two main types of enzymes involved in the initial steps of amino acid catabolism, which plays a key role in the cheese flavor development. In the present work, glutamate dehydrogenase and aminotransferase activities were screened in twenty one strains of lactic acid bacteria of dairy interest, either cheese-isolated or commercial starters, including fifteen mesophilic lactobacilli, four thermophilic lactobacilli, and two streptococci. The strains of Streptococcus thermophilus showed the highest glutamate dehydrogenase activity, which was significantly elevated compared with the lactobacilli. Aspartate aminotransferase prevailed in most strains tested, while the levels and specificity of other aminotransferases were highly strain- and species-dependent. The knowledge of enzymatic profiles of these starter and cheese-isolated cultures is helpful in proposing appropriate combinations of strains for improved or increased cheese flavor.

Fetal Rhd genotyping using real-time polymerase chain reaction analysis of cell-free fetal DNA in pregnancy of rhd negative women in south of Iran

Background: Maternal-fetal RhD antigen incompatibility causes approximately 50% of clinically significant alloimmunization cases. The routine use of prophylactic anti-D immunoglobulin has dramatically reduced hemolytic disease of the fetus and newborn. Recently, fetal RHD genotyping in RhD negative pregnant women has been suggested for appropriate use of anti-D immunoglobulin antenatal prophylaxis and decrease unnecessary prenatal interventions

Materials and Methods: In this prospective cohort study, in order to develop a reliable and non-invasive method for fetal RHD genotyping, cell free fetal DNA [cffD-NA] was extracted from maternal plasma. Real-time quantitative polymerase chain reaction [qPCR] for detection of RHD exons 7, 5, 10 and intron 4 was performed and the results were compared to the serological results of cord blood cells as the gold standard method. SRY gene and hypermethylated Ras-association domain family member 1 [RASSF1A] gene were used to confirm the presence of fetal DNA in male and female fetuses, respectively

Results: Out of 48 fetuses between 8 and 32 weeks [wks] of gestational age [GA], we correctly diagnosed 45 cases [93.75%] of RHD positive fetuses and 2 cases [4.16%] of the RHD negative one. Exon 7 was amplified in one sample, while three other RHD gene sequences were not detected; the sample was classified as inconclusive, and the RhD serology result after birth showed that the fetus was RhD-negative

Conclusion: Our results showed high accuracy of the qPCR method using cffDNA for fetal RHD genotyping and implicate on the efficiency of this technique to predict the competence of anti-D immunoglobulin administration

Circulating cell free DNA as a predictor of systemic lupus erythematosus severity and monitoring of therapy

Background: Systemic lupus erythematosus [SLE] is the most heterogeneous chronic autoimmune disease; it is characterized by the presence of auto reactive B and T cells, responsible for the aberrant production of a broad and heterogeneous group of autoantibodies. Recent studies using various detection methods have demonstrated the elevations of circulating DNA in SLE patients

Aim of the study: The current study aimed to measure cell-free DNA [cf-DNA] in SLE patients as a potential tool to predict disease activity and treatment follow up

Subjects and methods: 52 of SLE patients with age ranging from 10 to 48 years were randomly selected and 25 healthy subjects with age and gender matched with the patients were included as a control group. Thorough clinical examination stressing on the central nervous system, vascular, renal, rash, musculoskeletal, mucocutaneous manifestations, and fever was done for patients. The following investigations were done: Complete blood count [CBC], kidney function tests, C-reactive protein [CRP], routine autoantibodies for autoimmune diseases, complements [C3 and C4], anti-nucleosome antibodies and cf-DNA by real time PCR [RT-PCR]

Results: The levels of anti-double stranded DNA [anti-dsDNA], anti-nucleosome Ab, and cf-DNA were significantly increased in SLE patients compared to controls. The cf-DNA level was correlated to markers of disease severity namely CRP and anti-nucleosome. A significant reduction in levels of cf-DNA, anti-nucleosome Ab and anti-dsDNA was noticed after therapy

Conclusion: Our findings support that the measurement of cf-DNA appears to be a useful marker in addition to laboratory tests used in SLE diagnosis. High correlation with markers of disease severity suggesting its role in disease pathogenesis and decreasing its level after therapy makes it to be a marker of treatment follow-up

Adenophora remotiflora protects human skin keratinocytes against UVB-induced photo-damage by regulating antioxidative activity and MMP-1 expression

BACKGROUND/OBJECTIVES: Chronic ultraviolet (UV) exposure-induced reactive oxygen species (ROS) are commonly involved in the pathogenesis of skin damage by activating the metalloproteinases (MMP) that break down type I collagen. Adenophora remotiflora (AR) is a perennial wild plant that inhabits Korea, China, and Japan. The present study investigated the protective effects of AR against UVB-induced photo-damage in keratinocytes. MATERIALS/METHODS: An in vitro cell-free system was used to examine the scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical and nitric oxide (NO). The effect of AR on ROS formation, antioxidant enzymes, elastase, MMP-1 level, and mRNA expression of MMP-1 were determined in UVB-irradiated human keratinocyte HaCaT cells. RESULTS: AR demonstrated strong DPPH free radical and NO scavenging activity in a cell-free system exhibiting IC50 values of 1.88 mg/mL and 6.77 mg/mL, respectively. AR pretreatment dose-dependently attenuated the production of UVB-induced intracellular ROS, and antioxidant enzymes (catalase and superoxide dismutase) were enhanced in HaCaT cells. Furthermore, pretreatment of AR prevented UVB-induced elastase and collagen degradation by inhibiting the MMP-1 protein level and mRNA expression. Accordingly, AR treatment elevated collagen content in UVB-irradiated HaCaT cells. CONCLUSION: The present study provides the first evidence of AR inhibiting UVB-induced ROS production and induction of MMP-1 as a result of augmentation of antioxidative activity in HaCaT human keratinocytes. These results suggest that AR might act as an effective inhibitor of UVB-modulated signaling pathways and might serve as a photo-protective agent.

The Polyphenol Chlorogenic Acid Attenuates UVB-mediated Oxidative Stress in Human HaCaT Keratinocytes

We investigated the protective effects of chlorogenic acid (CGA), a polyphenol compound, on oxidative damage induced by UVB exposure on human HaCaT cells. In a cell-free system, CGA scavenged 1,1-diphenyl-2-picrylhydrazyl radicals, superoxide anions, hydroxyl radicals, and intracellular reactive oxygen species (ROS) generated by hydrogen peroxide and ultraviolet B (UVB). Furthermore, CGA absorbed electromagnetic radiation in the UVB range (280-320 nm). UVB exposure resulted in damage to cellular DNA, as demonstrated in a comet assay; pre-treatment of cells with CGA prior to UVB irradiation prevented DNA damage and increased cell viability. Furthermore, CGA pre-treatment prevented or ameliorated apoptosis-related changes in UVB-exposed cells, including the formation of apoptotic bodies, disruption of mitochondrial membrane potential, and alterations in the levels of the apoptosis-related proteins Bcl-2, Bax, and caspase-3. Our findings suggest that CGA protects cells from oxidative stress induced by UVB radiation.

Superoxide Dismutase 1 Inhibits Alpha-Melanocyte Stimulating Hormone and Ultraviolet B-Induced Melanogenesis in Murine Skin

BACKGROUND: Over the last decade, the incidence of ultraviolet B (UVB)-related skin problems has increased. Oxidative stress caused by UVB induces the secretion of melanocyte growth and activating factors from keratinocytes, which results in the formation of cutaneous hyperpigmentation. Therefore, increasing the antioxidant abilities of skin cells is thought to be a beneficial strategy for the development of sunscreen agents. Superoxide dismutase 1 (SOD1) is an antioxidant enzyme that is known to exhibit antioxidant properties. OBJECTIVE: The purpose of this study was to investigate the effect of SOD1 on alpha-melanocyte stimulating hormone (alpha-MSH) and UVB-induced melanogenesis in B16F10 melanoma cells and HRM-2 melanin-possessing hairless mice. METHODS: The inhibitory effect of SOD1 on tyrosinase activity was evaluated in a cell-free system. Additional experiments were performed using B16F10 melanoma cells to demonstrate the effects of SOD1 in vitro, and HRM-2 melanin-possessing hairless mice were used to evaluate the antimelanogenic effects of SOD1 in vivo. RESULTS: We found that SOD1 inhibited melanin production in a dose-dependent manner without causing cytotoxicity in B16F10 melanoma cells. SOD1 did not inhibit tyrosinase activity under cell-free conditions. The results indicate that SOD1 may reduce pigmentation by an indirect, nonenzymatic mechanism. We also found that SOD1 decreased UVB-induced melanogenesis in HRM-2 melanin-possessing hairless mice, as visualized through hematoxylin and eosin staining and Fontana-Masson staining. CONCLUSION: Our results indicate that SOD1 has an inhibitory effect on alpha-MSH and UVB-induced melanogenesis, indicating that SOD1 may be a promising sunscreen agent.

Cell-free protein synthetic system: progress and applications in biopharmaceutical engineering / 生物工程学报

Cell-free protein synthesis (CFPS) systems based on crude cell extracts have been used in protein expression in vitro. With the researchers' endeavor for decades, the CFPS system has been developed as an important research tool in many frontiers of fundamental and applied biology because of its clear genetic background and simplicity to control the reaction. The yield of CFPS systems derived from prokaryote or eukaryote has increased to several grams per liter with constantly decreasing cost. Nowadays grams of protein could be prepared using a large-scale cell-free system. Recently, the advantages on the expression of complicated, toxic and membrane proteins have shown the great potential of the CFPS systems. The rapid progress of this technology made us to believe that it will take an important place in biopharmaceutical industries undoubtedly.

Scopoletin from Cirsium setidens Increases Melanin Synthesis via CREB Phosphorylation in B16F10 Cells

In this study, we isolated scopoletin from Cirsium setidens Nakai (Compositae) and tested its effects on melanogenesis. Scopoletin was not toxic to cells at concentrations less than 50 microM and increased melanin synthesis in a dose-dependent manner. As melanin synthesis increased, scopoletin stimulated the total tyrosinase activity, the rate-limiting enzyme of melanogenesis. In a cell-free system, however, scopoletin did not increase tyrosinase activity, indicating that scopoletin is not a direct activator of tyrosinase. Furthermore, Western blot analysis showed that scopoletin stimulated the production of microphthalmia-associated transcription factor (MITF) and tyrosinase expression via cAMP response element-binding protein (CREB) phosphorylation in a dose-dependent manner. Based on these results, preclinical and clinical studies are needed to assess the use of scopoletin for the treatment of vitiligo.

Cell-free DNA concentration and integrity as a screening tool for cancer.

AIM OF THE STUDY: This study aims to evaluate cell-free DNA (CFDNA) concentration and integrity in patients with malignant and nonmalignant diseases and in controls to investigate their value as a screening test for cancer, and to correlate them with clinicopathological parameters of cancer patients. MATERIALS AND METHODS: The study included three groups; group I: 120 cancer patients, group II: 120 patients with benign diseases and group III: 120 normal healthy volunteers as control. One plasma sample was collected from each subject. CFDNA was purified from the plasma then its concentration was measured and integrity was assessed by PCR amplification of 100, 200, 400, and 800 bp bands. RESULTS: There was a highly significant difference in CFDNA levels between cancer group and each of benign and control groups. AUC of ROC curve for cancer group versus normal and benign groups were 0.962 and 0.895, which indicated the efficiency of CFDNA as a marker of cancer. As for integrity, normal and benign subjects showed only two bands at 100 and 200 bp, while all cancer patients demonstrated the 400 bp band and 78% of them had the 800 bp whose presence correlated with vascular invasion. CONCLUSION: The combined use of CFDNA concentration and integrity is a candidate for a universal screening test of cancer. Upon setting suitable boundaries for the test it might be applied to identify cancer patients, particularly among subjects with predisposing factors. Being less expensive, CFDNA concentration could be applied for mass screening and for patients with values overlapping those of normal and benign subjects, the use of the more expensive, yet more specific, integrity test is suggested.

Simplification and optimization of the preparation of Escherichia coli extract for cell-free protein expression / 生物工程学报

Cell-free protein expression system is a new method to express target protein in vitro and has been widely applied to the study of protein structure, protein function and other related fields. Preparation of cell extract is one of the key factors that affect the efficiency of the cell-free system. To improve the efficiency and economical feasibility of cell-free protein synthesis, we discussed the parameters during the preparation of the cell extract. These parameters include centrifugation speed, pre-incubation, and dialysis. We used the green fluorescent protein as the reporter protein, and obtained a simple procedure for the preparation of Escherichia coli cell extract. A simple centrifugation step (12 000 x g, 10 min) followed by a brief incubation was sufficient for the preparation of an active cell extract to support protein expression with higher productivity (209 microg/mL). Compared to the traditional E. coli S30 procedure, the processing time was reduced by 62%, and the productivity was increased by 2.6 times. The new procedure will make the advantage of cell-free technology more obvious, and promote its wider application.

Fucoxanthin Protects Cultured Human Keratinocytes against Oxidative Stress by Blocking Free Radicals and Inhibiting Apoptosis

Fucoxanthin is an important carotenoid derived from edible brown seaweeds and is used in indigenous herbal medicines. The aim of the present study was to examine the cytoprotective effects of fucoxanthin against hydrogen peroxide-induced cell damage. Fucoxanthin decreased the level of intracellular reactive oxygen species, as assessed by fluorescence spectrometry performed after staining cultured human HaCaT keratinocytes with 2',7'-dichlorodihydrofl uorescein diacetate. In addition, electron spin resonance spectrometry showed that fucoxanthin scavenged hydroxyl radical generated by the Fenton reaction in a cell-free system. Fucoxanthin also inhibited comet tail formation and phospho-histone H2A.X expression, suggesting that it prevents hydrogen peroxide-induced cellular DNA damage. Furthermore, the compound reduced the number of apoptotic bodies stained with Hoechst 33342, indicating that it protected keratinocytes against hydrogen peroxide-induced apoptotic cell death. Finally, fucoxanthin prevented the loss of mitochondrial membrane potential. These protective actions were accompanied by the down-regulation of apoptosis-promoting mediators (i.e., B-cell lymphoma-2-associated x protein, caspase-9, and caspase-3) and the up-regulation of an apoptosis inhibitor (B-cell lymphoma-2). Taken together, the results of this study suggest that fucoxanthin defends keratinocytes against oxidative damage by scavenging ROS and inhibiting apoptosis.

Utilização de ácidos nucleicos fetais livres no plasma materno para o diagnóstico pré-natal: realidade do Brasil neste cenário / Use of cell-free fetal nucleic acids in maternal blood for prenatal diagnosis: the reality of this scenario in Brazil

A descoberta de ácidos nucleicos fetais livres no plasma de gestantes possibilitou o desenvolvimento de novos testes de diagnóstico pré-natal não invasivo para a determinação do sexo e do Rh fetal. Esses testes foram implantados no sistema de saúde pública de diversos países da Europa há mais de cinco anos. As novas possibilidades de aplicação diagnóstica dessas tecnologias são a detecção de aneuploidias cromossômicas fetais, de doenças monogênicas fetais e de distúrbios relacionados com a placenta, temas pesquisados intensivamente por diversos grupos ao redor do mundo. O objetivo deste estudo é expor a situação brasileira no âmbito de pesquisa e utilização clínica dos testes disponíveis comercialmente que utilizam esses marcadores moleculares plasmáticos, ressaltando as vantagens, tanto econômicas quanto de segurança, que os testes não invasivos têm em relação aos atualmente utilizados em nosso sistema de saúde pública.

The discovery of cell-free fetal nucleic acids in the plasma of pregnant women has allowed the development of new, noninvasive prenatal diagnostic tests for the determination of fetal gender and Rh. These tests have been implemented in the public health system in several countries of Europe for over five years. The new possibilities for diagnostic use of these technologies are the detection of fetal chromosomal aneuploidies, monogenic fetal disorders, and placental-related disorders, subjects that have been intensively studied by several groups around the world. The aim of this review was to assess the Brazilian research and clinical scenarios regarding the utilization of commercially available tests that use these plasma markers, stressing the advantages, both economic and safety-related, that non-invasive tests have when compared to those currently used in the Brazilian public health system.

Heparin-iron complex multilayer nanomodification improves hemocompatibility of decellular xenograft / 中南大学学报(医学版)

OBJECTIVE@#To improve the hemocompatibility of decellular vascular matrix via heparin-iron complex multilayers (HICMs) nanomodification.@*METHODS@#A novel thrombo-resistant surface for decellular xenograft was developed by alternating linkage of dihydroxy-iron and heparin to decellular bovine jugular vein (DC-BJV), and its surface characterization, biomechanical stability and hemocompatibility were detected by scanning electron microscopy, tensile test and hemocompatibility evaluation, respectively.@*RESULTS@#A toluidine blue colorimetric method indicated the amount of linked heparin was about (808±86) μg/cm2 per assembly-cycle. Scanning electron microscopic (SEM) images proved that HICMs were uniformly linked to and formed nanoscale films around the fibrils of DC-BJV. Toluidine blue staining histologic images showed that HICMs were linked mainly to DC-BJV surfaces. Washing test showed that the release of heparin was (281±43), (422 ± 60), (729±81), (1053±116), (1317±157), (1618±187) and (1945 ± 268 ) μg/cm(2) at 1 day, 1, 2, 3, 4, 6 and 8 week washing, respectively. Tensile tests showed an increased biomechanical stability. Hemocompatibility evaluations showed that PT and APTT of all the trial groups were above the normal reference ranges and that mean platelet count per 10000 μm2 area was 8±4 for HICMs layer-by-layer modified BJV (LBL-BJV) vs 48±16 for DC-BJV.@*CONCLUSION@#HICMs are firmly linked to DC-BJV, and can form nanoscale thrombo-resistant films, which yield a sustained release of heparin. HICMs nanomodification improves the hemocompatibility of decellular xenograft.

Emerging technology of in situ cell free expression protein microarrays

Recently, in situ protein microarrays have been developed for large scale analysis and high throughput studies of proteins. In situ protein microarrays produce proteins directly on the solid surface from pre-arrayed DNA or RNA. The advances in in situ protein microarrays are exemplified by the ease of cDNA cloning and cell free protein expression. These technologies can evaluate, validate and monitor protein in a cost effective manner and address the issue of a high quality protein supply to use in the array. Here we review the importance of recently employed methods: PISA (protein in situ array), DAPA (DNA array to protein array), NAPPA (nucleic acid programmable protein array) and TUSTER microarrays and the role of these methods in proteomics.

Dipeptides Inhibit Melanin Synthesis in Mel-Ab Cells through Down-Regulation of Tyrosinase

This study investigated the effects of proline-serine (PS) and valine-serine (VS) dipeptides on melanogenesis in Mel-Ab cells. Proline-serine and VS significantly inhibited melanin synthesis in a concentration-dependent manner, though neither dipeptide directly inhibited tyrosinase activity in a cell-free system. Both PS and VS down-regulated the expression of microphthalmia-associated transcription factor (MITF) and tyrosinase. In a follow-up study also described here, the effects of these dipeptides on melanogenesis-related signal transduction were quantified. Specifically, PS and VS induced ERK phosphorylation, though they had no effect on phosphorylation of the cAMP response element binding protein (CREB). These data suggest that PS and VS inhibit melanogenesis through ERK phosphorylation and subsequent down-regulation of MITF and tyrosinase. Properties of these dipeptides are compatible with application as skin-whitening agents.

Prenatal diagnosis of β-thalassaemia using cell-free fetal DNA in maternal plasma / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the clinical feasibility of cell-free fetal DNA (cffDNA)-based noninvasive prenatal diagnosis of β-thalassemia.</p><p><b>METHODS</b>Nine samples of amniotic fluid were obtained to detect the 8 common and 9 relatively rare mutation sites of β-thalassaemia in Guangdong Province. The maternal blood samples were also collected for extracting and purification of the cffDNA, and a duplex PCR was performed using 3 pairs of primers and the fetal β-globin genotype was analyzed by reverse dot-blot hybridization.</p><p><b>RESULTS</b>Among the 9 cases, 5 showed fetal genotypes of β-thalassemia inherited from the father by examination of the amniotic fluid, and 2 fetuses were identified to have β-thalassemia genes inherited from the father determined based on the cffDNA in the maternal blood.</p><p><b>CONCLUSIONS</b>The cffDNA-based noninvasive prenatal diagnosis is feasible for β-thalassemia, but the contamination of the maternal background DNA results in a low detection rate.</p>

Diagnóstico prenatal no invasivo: Ácidos nucleicos de origen fetal en sangre materna / Non invasive prenatal diagnosis: Fetal nucleic acid analysis in maternal blood

Las técnicas actuales de diagnóstico prenatal de enfermedades génicas y cromosómicas incluyen procedimientos invasivos que conllevan un pequeño, pero significativo, riesgo. Por muchos años se ha estudiado la posibilidad de utilizar células fetales en circulación materna; sin embargo, ha fracasado su implementación clínica debido a su escasez y persistencia luego del parto. Desde hace más de una década se detectó ADN fetal libre en sangre de embarazadas. Este sería de origen placentario e indetectable después del parto, y fuente de material fetal para el desarrollo de técnicas diagnósticas utilizando sangre materna. No obstante, la mayoría del ADN libre en circulación materna es de origen materno con una contribución fetal del 3% al 6% aumentando a lo largo de la gestación. Dado que los métodos actuales no permiten separar el ADN libre fetal del materno, las aplicaciones se focalizan en el análisis de genes no presentes en la madre, tales como secuencias del cromosoma Y, o gen RHD en madres Rh negativas, o mutaciones paternas o de novo. Asimismo, la detección de ARN fetal libre en sangre de embarazadas abrió la posibilidad de obtener información acerca de patrones de expresión génica de tejidos embrionarios y, utilizando genes que se expresan sólo en la unidad feto-placentaria, se podría establecer un control de presencia de material fetal, independiente del material genético de la madre. El presente trabajo describe las evidencias acerca del pasaje de ácidos nucleicos fetales a circulación materna, su aplicación actual en el diagnóstico prenatal y posibles usos futuros.

Current prenatal diagnosis of monogeneic and chromosomal diseases, includes invasive procedures which carry a small but significant risk. For many years, analysis of fetal cells in maternal circulation has been studied, however it has failed its clinical use due to the scarcity of these cells and their persistance after delivery. For more than a decade, the presence of cell-free fetal DNA in maternal blood has been identified. These fetal DNA fragments would derive from the placenta and are not detected after delivery, making them a source of fetal material for carrying out diagnosis techniques using maternal blood. However, the vast majority of cell free DNA in maternal circulation is of maternal origin, with the fetal component contributing from 3% to 6% and rising towards term. Available methodologies do not allow separation of fetal from maternal cell free DNA, so current applications have been focused on the analysis of genes not present in the mother, such as Y chromosome sequences, or RHD gene in RhD-negative women, or paternal or de novo mutations. Also, the detection of cell-free fetal RNA in maternal blood offers the possibility of obtaining information regarding genetic expression profiles of embrionic tissues, and using genes expressed only at the feto-placental unit, controls for the presence of fetal material could be established, regardless of maternal genetic tissue. The present article describes the evidences regarding the passage of fetal nucleic acids to maternal circulation, its current prenatal diagnosis application and possible future perspectives.