Free DNA Research Articles

85. Plasma Cell Free Deoxyribonucleic Acid (cfDNA) Fungal Polymerase Chain Reaction (PCR): a Non-Invasive Diagnostic for Invasive Fungal Disease Evaluation in At-Risk Pediatric Oncology and Stem Cell Transplant Patients

Abstract Background Molecular diagnostics appear promising for early, non-invasive detection of invasive fungal disease (IFD) in immunocompromised patients. Our clinical lab developed and validated cell free DNA (cfDNA) fungal polymerase chain reaction (PCR) assays (Table 1), which have been in clinical use since November 2020 and were recently included in an institutional pediatric clinical care pathway for prolonged febrile neutropenia. We aimed to evaluate the performance of these plasma cfDNA fungal PCR assays in pediatric oncology and hematopoietic stem cell transplant (HSCT) patients with clinical concern for IFD. Methods We initiated an observational study of inpatient oncology and HSCT patients who had plasma mold panel (+/- Candida panel) cfDNA fungal PCR obtained as part of an IFD evaluation at our freestanding quaternary care children’s hospital. The primary outcome was IFD clinical diagnosis (proven, probable, possible, unlikely) as per EORTC/MSG† definitions within one month of the cfDNA fungal PCR, which was assigned independently by two physicians, with a third physician utilized in cases of discrepancy. Patient demographics, hospital course, imaging results, and clinical laboratory data were abstracted and maintained in an encrypted REDCap© database. Results In a preliminary analysis of October 2021-March 2022 data, there were 21 IFD evaluations for 18 patients (Table 2). Most oncology evaluations were for prolonged febrile neutropenia, while many HSCT were non-neutropenic, but on enhanced immunosuppression with new clinical concerns (e.g., respiratory symptoms, persistent fever). Plasma cfDNA detected a mold or yeast consistent with the clinical presentation in 100% of the five proven/probable cases (Figures 1 & 2). All 14 possible IFD cases had a negative cfDNA fungal PCR. Proven cases are designated with blue icon, while the probable case is orange. All five cases were in oncology patients who did not have history of hematopoietic stem cell transplant. Cell free DNA (cfDNA) fungal polymerase chain reaction (PCR) results include the organism identified, followed by the cycle threshold (Ct) in parenthesis. Maximum Ct for the assay is 45. Abbreviations: AG: Aspergillus galactomannan index (Ref <0.5); ALL: acute lymphoblastic leukemia. BAL: bronchoalveolar lavage; 1,3-BDG: 1,3-beta-D-glucan (Ref <60 pg/ml); cfDNA: cell free deoxyribonucleic acid; CNS: central nervous system; EORTC/MSG: European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group & the National Institute of Allergy & Infectious Diseases Mycoses Study Group; L-AmB: liposomal amphotericin B; SARS-CoV-2: severe acute respiratory syndrome associated with coronavirus 2. Conclusion Upfront plasma cfDNA fungal PCR successfully detected a relevant mold or yeast with short turnaround time in 100% of cases that were later classified as proven/probable. This appears promising for early, noninvasive diagnosis that enables prompt optimization of antifungal and surgical management, particularly for mucormycosis cases. Additional data may permit consideration of Mucorales agents PCR as a new EORTC/MSG mycologic criteria. Disclosures Lauren E. Kushner, MD, Roman: Client of my husband's business..

Liquid biopsy leads to a paradigm shift in the treatment of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most cancers. Its 5-year survival rate is very low. The recent induction of neoadjuvant chemotherapy and improvements in chemotherapy for patients with pancreatic cancer have resulted in improved survival outcomes. However, the prognosis of pancreatic cancer is still poor. To dramatically improve the prognosis, we need to develop more tools for early diagnosis, treatment selection, disease monitoring, and response rate evaluation. Recently, liquid biopsy (circulating free DNA, circulating tumor DNA, circulating tumor cells, exosomes, and microRNAs) has caught the attention of many researchers as a new biomarker that is minimally invasive, confers low-risk, and displays an overall state of the tumor. Thus, liquid biopsy does not employ the traditional difficulties of obtaining tumor samples from patients with advanced PDAC to investigate their molecular biological status. In addition, it allows for long-term monitoring of the molecular profile of tumor progression. These could help in identifying tumor-specific alterations that use the target structure for tailor-made therapy. Through this review, we highlighted the latest discoveries and advances in liquid biopsy technology in pancreatic cancer research and showed how it can be applied in clinical practice.

A perifériás vérben keringő szabad DNS molekuláris vizsgálata epeúti malignitásokban

Tumor-derived free-circulating DNA in peripheral blood allows the study of the molecular genetic profile in cholangiocarcinomas and even the effective monitoring of the response to chemotherapy. The use of a liquid biopsy is a favourable solution, as repeated invasive histological sampling is much more practicable and avoidable. The efficiency of liquid biopsy-based sequencing increases with tumor progression and thus with the release of larger amounts of free DNA. In the present study, clinically relevant point mutations were detected from both histological and liquid biopsy specimens of bile duct tumors. During next-generation sequencing, histological and DNA samples obtained during liquid biopsy from 33 patients were analyzed using a 67-gene solid tumor panel. In our prospective study, we present a minimally invasive approach to identify molecular genetic changes in cholangiocarcinoma and gallbladder tumors. The diagnostic application of free DNA reflects the spatial heterogeneity of tumors, making it a new approach to precision oncology treatments. Orv Hetil. 2022; 163(50): 1982-1991.

Identification of liquid biopsy-based mutations in colorectal cancer by targeted sequencing assays

Recently, liquid biopsy, as a promising approach was introduced for the analysis of different tumor-derived circulating markers including tumor DNA and cell free DNA (ct/cfDNA). Identification of mutations in cfDNA may allow the early detection of tumors, as well as predicting and monitoring treatment responses in a minimally invasive way. In the present study, we used commercially available gene panels to verify the mutation overlap between liquid biopsy and abnormalities detected in colorectal tumor tissue. The two panels (Archer®VariantPlex®Solid Tumor and LIQUIDPlexTM ctDNA) overlap in 23 genes, which enables a comprehensive view of tumor-plasma mutational status by next generation sequencing. We successfully analyzed 16 plasma and 16 tumor samples. We found that 87% of tumor tissues contained 44 mutations in 12 genes and 43.8% of cfDNA harbored 13 mutations in 5 genes. To verify whether the mutation pattern of the tumor DNA could be consistently detected in plasma cfDNA, we compared the alterations between cfDNA and matched tissue DNA in nine patients. Six of the 9 tumor tissues harbored mutations in TP53, KRAS or MET genes, those were not detectable by the ctDNA kit, even eventhough the exons of these genes overlap in both panels. Comparing the mutational patterns of the matched samples, we found that only one cfDNA had the same mutations (KRAS, SMAD4 and TP53) in the paired tissue. The results of the comparison between tumor tissue DNA and matched plasma cfDNA underline the importance of studying the paired solid tumor and plasma samples together.

A single-stranded DNA-based and terbium (III) fluorescent probe for facile and rapid detection of mercury (II)

Hg2+, as a highly dangerous pollutant, seriously affects public health and food safety. In this work, a biosensor based on single-stranded DNA and Tb3+ fluorescent probe was constructed for facile and rapid detection of Hg2+. The detection method only needs one DNA strand, which consists of two parts: the G-rich sequence is the Tb3+ luminescent antenna ligand and the T-rich sequence is the Hg2+ recognition probe. Free mercury-specific DNA (MSD) in an aqueous solution could significantly enhance Tb3+ luminescence. Upon the addition of Hg2+, the conformation of MSD will switch from the free random coil structure to the hairpin structure. Thus, Tb3+ was released and the fluorescence of Tb3+ was decreased. After condition optimization, the change of fluorescence intensity was proportional to the logarithmic concentration of Hg2+ from 0.01 to 10 μM with a detection limit of 1.9 nM. In addition, the detection results of Hg2+ in real samples were satisfactory. The designed fluorescent probe has great advantages in simplicity and functionality and has great development potential in food safety and environmental pollution.

Identification of DNA methylation signatures for hepatocellular carcinoma detection and microvascular invasion prediction

Background and aimPreoperative evaluation of microvascular invasion (MVI) in patients with hepatocellular carcinoma (HCC) is important for surgical strategy determination. We aimed to develop and establish a preoperative predictive model for MVI status based on DNA methylation markers.MethodsA total of 35 HCC tissues and the matched peritumoral normal liver tissues as well as 35 corresponding HCC patients’ plasma samples and 24 healthy plasma samples were used for genome-wide methylation sequencing and subsequent methylation haplotype block (MHB) analysis. Predictive models were constructed based on selected MHB markers and 3-cross validation was used.ResultsWe grouped 35 HCC patients into 2 categories, including the MVI− group with 17 tissue and plasma samples, and MVI + group with 18 tissue and plasma samples. We identified a tissue DNA methylation signature with an AUC of 98.0% and a circulating free DNA (cfDNA) methylation signature with an AUC of 96.0% for HCC detection. Furthermore, we established a tissue DNA methylation signature for MVI status prediction, and achieved an AUC of 85.9%. Based on the MVI status predicted by the DNA methylation signature, the recurrence-free survival (RFS) and overall survival (OS) were significantly better in the predicted MVI− group than that in the predicted MVI + group.ConclusionsIn this study, we identified a cfDNA methylation signature for HCC detection and a tissue DNA methylation signature for MVI status prediction with high accuracy.

Cell Free Fetal DNA As Biomarker for Pregnancy Loss Disorders

Cell Free Fetal DNA As Biomarker for Pregnancy Loss Disorders

Serum circulating free DNA of syncytin-1 as a novel molecular marker for early diagnosis of non-small-cell lung cancer.

Background: Liquid biopsy has been receiving attention as an emerging detection technology in the clinical application of non-small-cell lung cancer (NSCLC). Methods: We quantified serum circulating free DNA (cfDNA) of syncytin-1 in 126 patients and 106 controls, analyzed the correlation of level with pathological parameters and explored diagnostic utility. Results: The cfDNA of syncytin-1 levels in NSCLC patients were higher than healthy controls (p<0.0001). These levels were associated with smoking history (p=0.0393). The area under the curve of cfDNA of syncytin-1 was 0.802, and combination of cfDNA of syncytin-1/cytokeratin 19 fragment antigen 21-1/carcinoembryonic antigen markers improved diagnostic efficiency. Conclusion: The cfDNA of syncytin-1 was detected in NSCLC patients and can be used as a novel molecular marker for early diagnosis.

Stabilization of DNA fork junctions by Smc5/6 complexes revealed by single-molecule imaging.

SMC complexes play key roles in genome maintenance, where they ensure efficient genome replication and segregation. The SMC complex Smc5/6 is a crucial player in DNA replication and repair, yet many molecular features that determine its roles are unclear. Here, we use single-molecule microscopy to investigate Smc5/6's interaction with DNA. We find that Smc5/6 forms oligomers that dynamically redistribute on dsDNA by 1D diffusion and statically bind to ssDNA. Using combined force manipulation and single-molecule microscopy, we generate ssDNA-dsDNA junctions that mimic structures present in DNA repair intermediates or replication forks. We show that Smc5/6 accumulates at these junction sites, stabilizes the fork, and promotes the retention of RPA. Our observations provide a model for the complex's enrichment at sites of replication stress and DNA lesions from where it coordinates the recruitment and activation of downstream repair proteins.

PP096 A prospective study to evaluate the role of cell free DNA and DNA integrity index in assessing the response to neoadjuvant chemotherapy in patients with breast carcinoma

PP096 A prospective study to evaluate the role of cell free DNA and DNA integrity index in assessing the response to neoadjuvant chemotherapy in patients with breast carcinoma

Efficacy and safety of alectinib in ALK-positive non-small cell lung cancer and blood markers for prognosis and efficacy: a retrospective cohort study

Alectinib is a second generation of ALK-tyrosine kinase inhibitors (ALK-TKIs), which has attracted much attention in the treatment of ALK-positive non-small cell lung cancer (NSCLC). At present, there are few reports on the efficacy and safety of alectinib in Chinese population. Moreover, biomarkers reflecting prognosis and efficacy are exceedingly needed. This study assessed the efficacy of alectinib in patients with ALK-positive NSCLC and analyzed the prognostic factors. Patients with ALK-positive NSCLC who were confirmed by histopathology or cytology at the Affiliated Cancer Hospital of Nanjing Medical University between October 2018 and October 2021 were enrolled. All patients were treated with alectinib. The clinical characteristics and circulating tumor biomarkers before and after treatment were collected. Kaplan-Meier test was used to calculate the progression-free survival (PFS). Univariate and multivariate Cox regression analyses were used to explore the influencing factors on PFS. Incidence of adverse events was observed. Twenty patients progressed after first-line treatment (n=59) with alectinib, and 21 patients progressed following second-line treatment (n=36) with alectinib. The median PFS of first-line treatment patients was not achieved, and the median PFS of patients undergoing second-line treatment was 15.0 months [95% confidence interval (CI): 0.00-32.23]. The most common adverse reactions were liver dysfunction (37.50%), anemia (37.50%), and constipation (20.83%). The incidence of grade III and above adverse reactions was 6.25%. Univariate analysis showed that neutrophil-to-lymphocyte ratio [NLR; hazard ratio (HR) =0.424, P=0.005] carcinoembryonic antigen (CEA; HR =0.482, P=0.029), lactate dehydrogenase (LDH; HR =0.327, P<0.001), carbohydrate antigen (CA)199 (HR =0.313, P=0.002), and circulating cell free DNA (cfDNA; HR =0.229, P=0.008) concentration levels were associated with PFS, and multivariate analysis showed that NLR (HR =3.058, P=0.034) was independent prognostic factor. After three months of treatment, CEA, CA199, NLR, and LDH, could further predict the prognosis of alectinib treatment. The efficacy and safety of alectinib as a first-line or second-line treatment for ALK-positive NSCLC in keeping with published prospective studies. CEA, CA199, NLR, and LDH within the normal range after three months of treatment were associated with good prognosis. Detection of serum tumor markers can indicate therapeutic success in patients treated with alectinib.

A study on maternal and fetal cell free DNA (cffDNA) for predicting the adverse pregnancy outcomes

This gender-independent detection of cell-free fetal DNA in maternal plasma using RASSF1A/beta-actin has curtained off a new dimension regarding its utility to predict the adverse pregnancy outcomes. Recent efforts have been directed at developing sequences from cell-free fetal DNA (cffDNA) as markers for pregnancy outcomes. The utility of cffDNA using the methylation-dependent DSCR3 and RASSF1A markers along with total cell-free DNA (cf-DNA) in maternal serum by HYP2 marker are useful in predicting adverse pregnancy outcomes. Indigenously developed low-cost method of the gender-independent sequence markers from cffDNA was investigated and evaluated with the standardized commercial kits as predictive markers for adverse pregnancy outcomes. In the present study, we have tested whether the elevated amount of cffDNA in maternal plasma is associated with adverse pregnancy outcomes and development of new marker by the low-cost method to predict adverse pregnancy outcomes. 210 pregnant women within the age group of 20 – 30 years attending for routine antenatal checkups after 20 weeks with fulfilling the diagnostic criteria of adverse pregnancy outcomes were included in our study. Age-matched pregnant women without adverse pregnancy outcomes were included as controls (n=210). Identification of cell-free fetal DNA (cffDNA) in maternal plasma by using in-house methods (Guanidium isothiocyanate) was found comparable with commercial kit and its content (GE/ µl) in adverse pregnancy outcomes subjects were significantly higher than the normotensive subjects. Our results indicated that indigenously developed method for detection of gender-independent cffDNA can be applicable for screening test of adverse pregnancy outcome.

Current Trends in Liquid Biopsy Technology for Early Diagnosis of Metastatic Renal Cell Carcinoma

Clear cell renal cell carcinoma (ccRCC) is a disease with a wide variety of clinical progressions such as the rate of disease progression or the degree of metastasis. About 30% of ccRCC patients suffer from metastatic diseases, and about 30% develop metastasis after diagnosis. In the case of metastatic RCC, early prediction of the disease is important because of the poor prognosis, but ccRCC-specific molecular markers for clinical use are not available yet. As an alternative, liquid biopsy, which can find molecules released from tumor tissues in circulating blood and obtain information on metastatic dissemination and recurrence of ccRCC, is emerging. In this article, we will introduce molecules such as cell free DNA, cell free RNA, protein, and exosomes available as circulating biomarkers for liquid biopsy. We will also introduce some promising technologies that can compensate for the limitations of liquid biopsy.

Risque de trisomie 21 discordant en cas de marqueurs sériques très bas : à propos de cinq cas de triploïdie digynique

ObjectiveWe compare the risk of Down syndrome among five patients carrying a foetus with digynic triploidy and suggest a course of action for these particular serological profiles. MethodsThe concentrations of the different markers used are transformed into multiples of the median by using each of the three software types present on the French market which then determine the risk of Down syndrome. ResultsFor comparable biochemical and ultrasound profiles, the risk of Down syndrome turns out to be vastly different depending on the type of software employed. The relevance of an immediate diagnostic procedure, of a cell free DNA test or of a basic ultrasound follow-up then arises, leading to a potentially variable care pathway for the patient. ConclusionsThis study confirms that for this type of biochemical profile, the laboratory's advisory service is fundamental, that a control ultrasound is essential and that an invasive procedure must be used almost invariably due to the extremely substantial risk factors.

Using Genomic Variation to Distinguish Ovarian High-Grade Serous Carcinoma from Benign Fallopian Tubes.

In this retrospective, pilot study, we extracted DNA and RNA from HGSC specimens and from benign fallopian tubes. Then, we performed whole exome sequencing and RNA sequencing, and identified single nucleotide variants (SNV), copy number variants (CNV) and structural variants (SV). We used these variants to create prediction models to distinguish cancer from benign tissue. The models were then validated in independent datasets and with a machine learning platform. The prediction model with SNV had an AUC of 1.00 (95% CI 1.00-1.00). The models with CNV and SV had AUC of 0.87 and 0.73, respectively. Validated models also had excellent performances. Genomic variation of HGSC can be used to create prediction models which accurately discriminate cancer from benign tissue. Further refining of these models (early-stage samples, other tumor types) has the potential to lead to detection of ovarian cancer in blood with cell free DNA, even in early stage.

Tuberculosis detection from raw sputum samples using Au-electroplated screen-printed electrodes as E-DNA sensor.

Tuberculosis (TB) remains a leading cause of death globally, especially in underdeveloped nations. The main impediment to TB eradication is a lack of efficient diagnostic tools for disease diagnosis. In this work, label free and ultrasensitive electrochemical DNA biosensor for detecting Mycobacterium tuberculosis has been developed based on the electrodeposition of gold nanoparticles on the surface of carbon screen-printed carbon electrode (Zensors) for signal amplification. Particularly, screen-printed electrodes were modified by electrochemical deposition of Au to enhance the conductivity and facilitate the immobilization of ssDNA probes via Au-S bonds. The electrochemically modified SPEs were characterized using Scanning electron microscopy/Energy Dispersive X-Ray Analysis (SEM/EDX) and X-Ray Diffraction (XRD). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were used to investigate the DNA hybridization between single-stranded (ssDNA) probe and target DNA (tDNA). Under the ideal conditions, DPV exhibited a correlation coefficient R2 = 0.97, when analyzed with different tDNA concentrations. The proposed DNA biosensor exhibits a good detection range from 2 to 10nm with a low detection limit of 1.91nm, as well as high selectivity that, under ideal conditions, distinguishes non-complementary DNA from perfectly matched tDNA. By eliminating the need for DNA purification, this work paves the path for creating disposable biosensors capable of detecting DNA from raw sputum samples.

Circulating tumour cell combined with DNA methylation for early detection of hepatocellular carcinoma.

Background: The inadequate early detection strategies makes hepatocellular carcinoma (HCC) patients with poor prognisis. Therefore, more effective detection methods are urgently needed for early detection and early intervention of HCC. Methods: 17 cases of suspected HCC patients and 11 cases of HBV-related decompensated cirrhosis (HBV-DeCi) patients were enrolled. For each patient, 5ml blood sample was separated into circulating tumor cells (CTCs) and plasma, CTCs were stained with Diff staining for counting. Plasma was used for extracting cell free DNA (cfDNA) and then analyzed by qMSP assay. Ct values were recorded for GNB4 and Riplet as target genes and β-actin as an endogenous reference gene. Finally, clinical efficacy of CTC count combined with GNB4/Riplet methylation detection for early diagnosis of HCC was analyzed. Results: The CTC of HCC patients has pleomorphic characteristics, but it is difficult to distinguish from other blood cells with non-obviously pleomorphic of CTC. Although a small number of CTCs can also be detected in HBV-DeCi patients (control group), the number is significantly lower than that in HCC patients, the sensitivity and specificity of CTC for HCC detection were 70.6% and 90.9% (AUC = 0.81). The Ct values of GNB4 and Riplet methylation were significantly different between HCC patients and control group patients. When CTC combined with two genes, the AUC value was significantly increased to 0.98, the sensitivity was 88.2%, and the specificity was 100%. Conclusion: Our study has developed a novel test that CTC count combined with GNB4/Riplet methylation detection and showed its high performance for early diagnosis of HCC.

Hypertensive disorders of pregnancy share common cfDNA methylation profiles

Hypertensive disorders of pregnancy (HDP) contribute substantially to perinatal morbidity and mortality. Epigenetic changes point towards cardio-metabolic dysregulation for these vascular disorders. In early pregnancy, epigenetic changes using cell free DNA (cfDNA) are largely unexplored. We aimed to investigate these in HDP between 11 and 14 weeks of gestation by analysis of cfDNA methylation profiles in patients with hypertensive disorders. We identified patients without chronic hypertension but with subsequent development of preeclampsia (PE) (n = 11), with chronic hypertension (HT) but without PE development (n = 14), and lacking both PE and HT (n = 422). We matched patients according to PE risk factors into three groups (n = 5 each group): (1) PE: no HT but PE development, (2) HT: chronic hypertension but no PE and (3) Control: no PE or HT. We successfully optimized our cfDNA isolation process prior to whole genome bisulfite sequencing. Analysis of cfDNA methylation changes indicate a common predisposition in PE and HT groups, chiefly of maternal origin. Assessment of significant differentially methylated regions and annotated genes point towards a common cardiovascular predisposition in preeclampsia and hypertension groups in the first trimester. We postulate the pivotal role of the maternal cardiovascular system in HDP, which is already evident in the first trimester.

The integration of hybridization chain reaction (HCR) with fluorogenic silver nanoclusters (AgNCs) in an aggregation induced emission (AIE)-based nanosensor for sex determination and its forensic application

We have designed a novel turn-on label-free nanosensor for sex determination by targeting DYS14 marker found on Y chromosome via integrating hybridization chain reaction (HCR) and silver nanoclusters (AgNCs). AgNCs are used as fluorophores, and for the first time, they are formed separately on a DNA template sequence other than the hairpins of HCR, to fulfill their sensitive synthesis and drive their aggregation induced emission (AIE) enhancement. While HCR acts as a simple, enzyme-free and isothermal amplification technique. The working principle is based on the hybridization of the target, when present, with a part of the hairpin H1 causing its opening, and then the other fragments open another hairpin H2 to hybridize with. As a last step, the free fragment found on H2 hybridizes with that attached to the nucleation sequence of AgNCs on the free DNA probes. As a result, a double stranded HCR product is formed, and the nanoclusters are placed in specific positions in a close proximity on it. This accumulation causes the phenomenon of AIE, and finally, the fluorescence emission intensity of AgNCs increases. This designed bioassay has the advantages of simple operation, cost effectiveness, rapid results, and good stability and specificity. Furthermore, it is the first time; an optical biosensor is introduced for this gene. Moreover, the detection limit of this assay is as low as 0.87 pM, and it also showed satisfying performance in real samples. This platform holds great promise for the application of label-free HCR/AgNCs nanosensors to other biomarkers.

Analysis of cellular and cell free mitochondrial DNA content and reactive oxygen species levels in maternal blood during normal pregnancy: a pilot study

BackgroundAlterations in mitochondrial signatures such as mitochondrial DNA (mtDNA) content in maternal blood have been linked to pregnancy-related complications. However, changes in maternal mtDNA content, their distribution and associated signaling during normal pregnancies are not clear; which could suggest their physiological role in maternal adaptation to pregnancy related changes and a reference threshold. The aim of this study: to assess the distribution of mtDNA in peripheral blood and their association with circulatory ROS levels across different trimesters of healthy pregnancy.MethodsIn this pilot cross sectional study, blood samples of normal pregnant women from each trimester (total = 60) and age-matched non-pregnant (NP) women as control group (n = 20) were analyzed for a) the relative distribution of mtDNA content in cellular and cell free (plasma) fractions using relative quantitative polymerase chain reaction (qPCR) and b) the levels of circulating reactive oxygen species (ROS) by measurement of plasma H2O2. The results were compared between pregnant and NP groups and within trimesters for significant differences, and were also analyzed for their correlation between groups using statistical methods.ResultsWhile, we observed a significant decline in cellular mtDNA; plasma mtDNA was significant increased across all trimesters compared to NP. However, from comparisons within trimesters; only cellular mtDNA content in 3rd trimester was significantly reduced compared to 1st trimester, and plasma mtDNA did not differ significantly among different trimesters. A significantly higher level of plasma H2O2 was also observed during 3rd trimester compared to NP and to 1st trimester. Correlation analysis showed that, while cellular mtDNA content was negatively correlated to plasma mtDNA and to plasma H2O2 levels; plasma mtDNA was positively correlated with plasma H2O2 content.ConclusionsThis study suggested that normal pregnancy is associated with an opposing trend of reduced cellular mtDNA with increased circulatory mtDNA and H2O2 levels, which may contribute to maternal adaptation, required during different stages of pregnancy. Estimation of mtDNA distribution and ROS level in maternal blood could show mitochondrial functionality during normal pregnancy, and could be exploited to identify their prognostic/ diagnostic potential in pregnancy complications.