Timing Matters: Effects of Early and Late Estrogen Replacement Therapy on Glucose Metabolism and Vascular Reactivity in Ovariectomized Aged Wistar Rats.

Cardiovascular disease incidence increases after menopause due to the loss of estrogen cardioprotective effects. However, there are conflicting data regarding the timing of estrogen therapy (ERT) and its effect on vascular dysfunction associated with impaired glucose metabolism. The aim of this work was to evaluate the effect of early and late ERT on blood glucose/insulin balance and vascular reactivity in aged ovariectomized Wistar rats. Eighteen-month-old female Wistar rats were randomized as follows: (1) sham, (2) 10-week postovariectomy (10 w), (3) 10 w postovariectomy+early estradiol therapy (10 w-early E2), (4) 20-week postovariectomy (20 w), and (5) 20-week postovariectomy+late estradiol therapy (20 w-late E2). Early E2 was administered 3 days after ovariectomy and late therapy after 10 weeks, in both groups. 17ß-Estradiol (E2) was administered daily for 10 weeks (5 µg/kg/day). Concentration-response curves to angiotensin II, KCl, and acetylcholine (ACh) were performed. Heart rate (HR), diastolic and systolic blood pressure (DBP and SBP), glucose, insulin, HOMA-IR, and nitric oxide (NO) levels were determined. Higher glucose levels were found in all groups compared to the sham group, except the 20 w-late E2 group. Insulin was increased in all ovariectomized groups compared to sham. The HOMA-IR index showed insulin resistance in all ovariectomized groups, except for the 10 w-early E2 group. The 10 w-early E2 group increased NO levels vs. the 10 w group. After 10 w postovariectomy, the vascular response to KCl and Ach increases, despite early E2 administration. Early and late E2 treatment decreased vascular reactivity to Ang II. At 20-week postovariectomy, DBP increased, even with E2 administration, while SBP and HR remained unchanged. The effects of E2 therapy on blood glucose/insulin balance and vascular reactivity depend on the timing of therapy. Early ERT may provide some protective effects on insulin resistance and vascular function, whereas late ERT may not have the same benefits.

Correction: Identification of drug resistance mutations among Mycobacterium bovis lineages in the Americas.

[This corrects the article DOI: 10.1371/journal.pntd.0009145.].

An Epistatic Network Describes oppA and glgB as Relevant Genes for Mycobacterium tuberculosis.

Mycobacterium tuberculosis is an acid-fast bacterium that causes tuberculosis worldwide. The role of epistatic interactions among different loci of the M. tuberculosis genome under selective pressure may be crucial for understanding the disease and the molecular basis of antibiotic resistance acquisition. Here, we analyzed polymorphic loci interactions by applying a model-free method for epistasis detection, SpydrPick, on a pan-genome-wide alignment created from a set of 254 complete reference genomes. By means of the analysis of an epistatic network created with the detected epistatic interactions, we found that glgB (α-1,4-glucan branching enzyme) and oppA (oligopeptide-binding protein) are putative targets of co-selection in M. tuberculosis as they were associated in the network with M. tuberculosis genes related to virulence, pathogenesis, transport system modulators of the immune response, and antibiotic resistance. In addition, our work unveiled potential pharmacological applications for genotypic antibiotic resistance inherent to the mutations of glgB and oppA as they epistatically interact with fprA and embC, two genes recently included as antibiotic-resistant genes in the catalog of the World Health Organization. Our findings showed that this approach allows the identification of relevant epistatic interactions that may lead to a better understanding of M. tuberculosis by deciphering the complex interactions of molecules involved in its metabolism, virulence, and pathogenesis and that may be applied to different bacterial populations.

Intra-host genetic population diversity: Role in emergence and persistence of drug resistance among Mycobacterium tuberculosis complex minor variants.

Drug resistant tuberculosis (DR-TB) is an important public health issue in different parts of the world. Mycobacterium tuberculosis complex variants (MTBC vars) preferentially infect certain hosts, limiting their distribution to different ecosystems. However, MTBC vars can infect other hosts beyond their preferred target potentially contributing to persistence of drug resistance (DR) in other niches. Here, we performed a comprehensive intra-host genetic analysis for the identification of DR-related mutations among all MTBC minor vars whole genome sequences (8,095 strains) publicly available worldwide. High confidence drug-resistance mutations in katG (isoniazid), rpsL (streptomycin), pncA (pyrazinamide), rpoB (rifampicin) and gyrA (fluoroquinolones) genes were identified among intrahost minor sub-populations in 197 different strains (2.43%) belonging to vars africanum, bovis, caprae, microti, orygis and pinnipedii. In addition, a three-dimensional structure modeling analysis to assess the role of novel mutations was also performed. Our findings highlight the importance of detecting discrete intra-host populations carrying DR mutations.

Viral infections in stillbirth: a contribution underestimated in Mexico?

OBJECTIVES: To analyze the role of viral infections as etiology of stillbirths in Mexico and their epidemiological impact in the context of the global Every Newborn Initiative. METHODS: A comprehensive literature search was performed in electronic databases related to stillbirth and viral infections published prior to January 19th 2021. Stillbirths records and causes from National Mexican databases, during 2008-2019 period were also computed. RESULTS: Only two articles with a direct relationship between viral infection and stillbirth were found, and one article with an indirect serological association was identified. During the analyzed period there were 198,076 stillbirths, with a National stillbirth rate (SBR) ranging from 6.9 to 6.5 between 2008 and 2014, with a subsequent increase to reach 7.7 in 2019. Only 19 cases were attributed to viral causes and a specific virus was identified in 11. The main causes of early stillbirth were a fetus with premature rupture of membranes and light for gestational age, and for late stillbirth these were fetus affected by oligohydramnios and slow fetal growth. The percentage classified as unspecified deaths varied from 34.4-41.9%. CONCLUSIONS: In Mexico, there has been an increase in SBR during last years, but the goals of the Every Newborn Initiative is met. More than 14,500 stillbirths with at least 5,100 unspecified cases have been reported per year, and only 11 cases were attributable to a specific virus, highlighting the serious underestimation of cases and the need of implementation of routine viral diagnosis methods to improve the care of this global health problem.

Is it possible to treat nonalcoholic liver disease using a flavanol-based nutraceutical approach? Basic and clinical data.

Nonalcoholic fatty liver disease (NAFLD) is characterized by a spectrum of diseases, ranging from simple steatosis to hepatocellular carcinoma. The main factors for NAFLD are closely related to obesity, insulin resistance, intestinal microbiota alterations, hyperinsulinism, low-grade systemic inflammation, nitroxidative stress, lipid peroxidation, and mitochondrial dysfunction. Currently, the treatment of NAFLD is based on diet and exercise because, to date, there is no specific pharmacological agent, already approved, that raises the need for new therapeutic strategies. Nutraceuticals, such as polyphenols, have potential beneficial effects for health. In this article, the beneficial effects of epigallocatechin-3-gallate (EGCG) and (-)-epicatechin (EC) are discussed. EGCG is the main catechin in green tea, which has shown in various studies its potential effect preventing and treating NAFLD since it has shown antihyperlipidemic, anti-inflammatory, antifibrotic, antioxidant, and improvement of liver lipid metabolism. However, it has been found that excessive consumption may cause hepatotoxicity. EC is widely distributed in nature (fruits and vegetables). This flavanol has shown many beneficial effects, including antihypertensive, anti-inflammatory, anti-hyperglycemic, antithrombotic, and antifibrotic properties. It increases mitochondrial biogenesis, and it also has effects on the regulation of synthesis and metabolism of lipids. This flavanol is a nontoxic substance; it has been classified by the United States Food and Drug Administration as harmless. The EC-induced effects can be useful for the prevention and/or treatment of NAFLD.

Homologous recombination as a mechanism of genetic changes in bovine parainfluenza-3 virus.

Bovine parainfluenza-3 virus (BPIV-3) is one of the main viruses associated with bovine respiratory disease complex (BRDC) worldwide. BPIV-3 infect the bovine respiratory tract causing from subclinical infections to severe pneumonia with significant economic losses in the cattle industry. BPIV-3 is a RNA virus with high genetic variability, nevertheless, the contribution of recombination events to its variability has not been assessed so far. In this study the 25 complete genome sequences (CGS) reported so far and 215 partial sequences of different viral genes of BPIV-3 were analyzed to determine their genotypes and subgenotypes, distribution, and the existence of potential recombination events. Based on the analysis of the HN, M, N, and P genes one hypothetical subgenotype was found (subgenotype A4). Four recombination events between sequences of swine and cattle were detected by RDP4 analysis in conjunction with phylogenetic incongruences in the L gene. In addition, 9 sequences reported from Argentina were found to be miss-classified. These results reveal that homologous recombination events have a relevant role in the evolution of BPIV-3 and highlight the importance of implement advanced molecular characterization to better understand the variability and evolution of BPIV-3 as a component of BRDC.

Identification of drug resistance mutations among Mycobacterium bovis lineages in the Americas.

Identifying the Mycobacterium tuberculosis resistance mutation patterns is of the utmost importance to assure proper patient's management and devising of control programs aimed to limit spread of disease. Zoonotic Mycobacterium bovis infection still represents a threat to human health, particularly in dairy production regions. Routinary, molecular characterization of M. bovis is performed primarily by spoligotyping and mycobacterial interspersed repetitive units (MIRU) while next generation sequencing (NGS) approaches are often performed by reference laboratories. However, spoligotyping and MIRU methodologies lack the resolution required for the fine characterization of tuberculosis isolates, particularly in outbreak settings. In conjunction with sophisticated bioinformatic algorithms, whole genome sequencing (WGS) analysis is becoming the method of choice for advanced genetic characterization of tuberculosis isolates. WGS provides valuable information on drug resistance and compensatory mutations that other technologies cannot assess. Here, we performed an analysis of the most frequently identified mutations associated with tuberculosis drug resistance and their genetic relationship among 2,074 Mycobacterium bovis WGS recovered primarily from non-human hosts. Full-length gene sequences harboring drug resistant associated mutations and their phylogenetic relationships were analyzed. The results showed that M. bovis isolates harbor mutations conferring resistance to both first- and second-line antibiotics. Mutations conferring resistance for isoniazid, fluoroquinolones, streptomycin, and aminoglycosides were identified among animal strains. Our findings highlight the importance of molecular surveillance to monitor the emergence of mutations associated with multi and extensive drug resistance in livestock and other non-human mammals.

Estrous cycle phase affects myocardial infarction through reactive oxygen species and nitric oxide.

INTRODUCTION: Myocardial infarction is the leading cause of death in women worldwide. Several studies have shown that estrogens play a cardioprotective role in women by decreasing reactive oxygen species (ROS) and increasing nitric oxide (NO). The aim of this work was to determine whether the evolution of myocardial infarction depends on the phase of the estrous cycle. METHODS: Female Wistar rats were randomized into the following groups with an (n = 7 per group): (1) ovariectomized (OVX-sham); (2) OVX-48 h coronary occlusion (CO); (3) OVX-2 w CO; (4) proestrus-sham; (5) proestrus-48 h CO; (6) proestrus-2 w CO; (7) estrus-sham; (8) estrus-48 h CO; and (9) estrus-2 w CO. We measured the percentage of myocardial necrosis, cardiac hypertrophy, hemodynamic parameters, and the production of NO and ROS, after acute and chronic myocardial infarction was induced in proestrus or estrus or ovariectomized female rats. RESULTS: The infarct area was reduced in the proestrus groups, while it was increased in the estrus and OVX groups. The left ventricular systolic pressure (LVSP) and ± dP/dt were reduced, but left ventricular diastolic pressure (LVDP) was increased in the OVX groups. NO was increased in the OVX + CO and estrus + CO groups. Production of ROS was increased in OVX rats after myocardial infarction but remained unchanged in proestrus and estrus. CONCLUSION: The phase of the estrous cycle in which the myocardial infarction occurs is important. When the coronary occlusion occurs during the proestrus phase, it prevents changes in cardiac function, the development of hypertrophy, oxidative stress and changes in NO levels, and reduces the extent of infarction.

Characterization of the IL-17 and CD4+ Th17 Cells in the Clinical Course of Dengue Virus Infections.

The aims of this study were to determine the involvement of interleukin 17 (IL-17) and IL-17-producing cells in dengue pathogenesis. Blood samples from dengue virus (DENV)-infected patients were collected on different days after the onset of symptoms. Patients were classified according to 1997 World Health Organization guidelines. Our study examined 152 blood samples from dengue fever (DF, n = 109) and dengue hemorrhagic fever (DHF, n = 43) patients and 90 blood samples from healthy controls (HC). High serum concentrations of IL-17A and IL-22 were also associated with DHF (IL-17A [DHF vs. DF, p < 0.01; DHF vs. HC, p < 0.0001]; IL-22 [DHF vs. DF, p < 0.05; DHF vs. HC, p < 0.0001]). Moreover, there was a positive correlation between serum levels of IL-17A and IL-23, a key cytokine that promotes IL-17-based immune responses (r = 0.4089, p < 0.0001). Consistent with the IL-17-biased immune response in DHF patients, we performed ex vivo activation of peripheral blood mononuclear cells (PBMCs) from DHF patients and flow cytometry analysis showed a robust IL-17-biased immune response, characterized by a high frequency of CD4+IL-17+ producing cells. Our results suggests IL-17-producing cells and their related cytokines can play a prominent role in this viral disease.

Utility of two DNA extraction methods using formalin-fixed paraffin-embedded tissues in identifying congenital cytomegalovirus infection by polymerase chain reaction.

Formalin-fixed paraffin-embedded (FFPE) tissues are a source of biological material for molecular studies; several methods to extract DNA from FFPE tissues have been reported. This process is challenging because of formaldehyde-induced cross-linking between proteins and DNA as well as molecule fragmentation when unbuffered formalin is used for fixation. Here, 2 methods for DNA extraction from FFPE tissues, based on a chelating resin and silica membrane columns, were modified and compared in their capacity to detect human cytomegalovirus (HCMV) in congenital infections. Both methods were tested on 121 samples of brain, lung, spleen, and liver derived from 36 deceased preterm newborns. Twelve patients were selected, and UL55 and UL75 HCMV genes were detected by polymerase chain reaction in 16/36 samples. These 2 methods represent a useful tool for DNA recovery from FFPE tissues and HCMV molecular identification with the advantage of low cost, minimal steps, minimal sample use, being solvent-free, and being easy to implement in the laboratory.

Differences in the expression of the renin angiotensin system and the kallikrein-kinin system during the course of myocardial infarction in male and female Wistar rats.

BACKGROUND: There is some evidence that components of the renin-angiotensin system and kallikrein-kinin system are not similarly regulated in both sexes. The aim of this work was to analyze the expression of angiotensin-converting enzyme, angiotensin-converting enzyme 2, angiotensin 1 receptor, angiotensin 2 receptor, beta-1 receptor, and beta-2 receptor during the evolution of myocardial infarction. METHODS: Thirty-six male and 36 female Wistar rats were used. Myocardial infarction was induced. Six groups of both sexes were formed, (n=6): (a) sham; (b) 48 h myocardial infarction; (c) one week myocardial infarction; (d) two weeks myocardial infarction; (e) three weeks myocardial infarction and (f) four weeks myocardial infarction. The expression was evaluated by real-time polymerase chain reaction on the penumbra of left ventricle. RESULTS: The mRNA expression of most biomarkers was lower in females than in males. During acute infarction, an increase of all protein expression was found in female and at two weeks while in the male only biomarker changes occurred at three weeks. In addition, in male biomarkers mRNA expression decreased during chronic infarction while in females it did not. CONCLUSIONS: The renin-angiotensin system and kallikrein-kinin system biomarkers expression occurs at earlier times in the female than in the male rat. In addition, during chronic myocardial infarction these biomarkers remained unchanged in females while in males they decreased.

Nosocomial transmission of extensively drug resistant Acinetobacter baumannii strains in a tertiary level hospital.

Acinetobacter baumannii is an opportunistic infectious agent that affects primarily immunocompromised individuals. A. baumannii is highly prevalent in hospital settings being commonly associated with nosocomial transmission and drug resistance. Here, we report the identification and genetic characterization of A. baumannii strains among patients in a tertiary level hospital in Mexico. Whole genome sequencing analysis was performed to establish their genetic relationship and drug resistance mutations profile. Ten genetically different, extensively drug resistant strains were identified circulating among seven wards. The genetic profiles showed resistance primarily against aminoglycosides and beta-lactam antibiotics. Importantly, no mutants conferring resistance to colistin were observed. The results highlight the importance of implementing robust classification schemes for advanced genetic characterization of A. baumannii clinical isolates and simultaneous detection of drug resistance markers for adequate patient's management in clinical settings.

A unique immune signature of serum cytokine and chemokine dynamics in patients with Zika virus infection from a tropical region in Southern Mexico.

OBJECTIVES: To describe the kinetics of circulating cytokines and chemokines in humans with ZIKAV infection. METHODS: Serum levels of different immune mediators in patients with ZIKAV infection were measured at distinct stages of the disease, as well as in culture supernatants from human monocytes infected with a clinical ZIKAV isolate. We also looked for clinical features associated with specific immune signatures among symptomatic patients. RESULTS: We evaluated 23 ZIKAV-infected patients. Their mean age was 32 ± 8.3 years and 65% were female. ZIKAV patients showed elevated IL-9, IL-17A, and CXCL10 levels at acute stages of the disease. At day 28, levels of CCL4 and CCL5 were increased, whereas IL-1RA, CXCL8 and CCL2 were decreased. At baseline, IL-7 was increased among patients with headache, whereas CCL2, and CCL3 were decreased in patients with bleeding and rash, respectively. Our clinical ZIKAV isolate induced a broad immune response in monocytes that did not resemble the signature observed in ZIKAV patients. CONCLUSIONS: We showed a unique immune signature in our cohort of ZIKAV-infected patients. Our study may provide valuable evidence helpful to identify immune correlates of protection against ZIKAV.

Genetic polymorphisms present in IL10, IL23R, NOD2, and ATG16L1 associated with susceptibility to inflammatory bowel disease in Mexican population.

OBJECTIVE: Ulcerative colitis and Crohn's disease are the two clinical forms of inflammatory bowel disease (IBD). Diverse studies have shown the association of single nucleotide polymorphism (SNP) in molecules of the immune system and the occurrence of IBD. Here, several SNPs of the immune system with controversial results for their association with UC and CD were evaluated in a Mexican population. METHODS: SNPs rs1800896, rs3024505 (IL-10); rs11209026 (IL23R); rs2066844, rs2066845 (NOD-2), and rs2241880 (ATG16L1) were assessed in 93 patients with IBD and 200 healthy controls by hybridization probes and quantitative PCR. RESULTS: The AG genotype for rs1800896 was associated with an increased risk for both UC and CD (P = 0.005 and P = 0.026, respectively); whereas the AA genotype presents a negative association (P = 0.011 for UC, and 0.0038 for CD). For this SNP, G allele was associated with risk of UC (P = 0-043) but not for CD. For the rs3024505 in IL-10, T allele was associated with UC (P = 0.011). Moreover, this allele was associated with early onset of UC (P = 0.033) and with the use of steroid treatment (P = 0.019). No significant differences for NOD2 (rs2066844T and rs2066845C), IL23R (rs11209026), and ATG16L1 (rs22411880) were found between cases and controls and the homozygous TT genotype for rs2066844 and CC for rs2066845 were not observed. CONCLUSION: Our results show both genotypic and phenotypic associations of IL-10 SNPs with IBD but not with the other immune-related SNPs studied in this Mexican cohort.

Combined Antihypertensive Therapies That Increase Expression of Cardioprotective Biomarkers Associated With the Renin-Angiotensin and Kallikrein-Kinin Systems.

Antihypertensive pharmacological treatments focus on the use of angiotensin-converting enzyme (ACE) inhibitors, AT1 receptor antagonists, and beta-blockers as single and combined treatments. The effect of single treatments on the mRNA expression of some components of the renin-angiotensin system has been studied, but not the effect of combined treatments. This study determined the expression of the AT1, AT2, B1, and B2 receptors and of the enzymes ACE and ACE2 in hypertensive rats treated with captopril-propranolol or losartan-propranolol. Methods: The mRNA expression of the receptors and enzymes was determined by reverse transcription-quantitative polymerase chain reaction in the aorta of spontaneously hypertensive rats under different treatments. Results: Rats under combined treatments showed a decrease in the expression of AT1 and ACE, and an increase in the expression of the B1 receptor (captopril + propranolol group: 0.43 ± 0.046, 2.243 ± 0.269, 3.356 ± 0.418; Group: losartan + propranolol: 0.727 ± 0.071, 0.852 ± 0.102, 1.277 ± 0.131 compared to the spontaneously hypertensive group: 1 ± 0.212, 1 ± 0.192, 1 ± 0.214). This decrease in the expression of ACE and AT1 suggests a reduction in the expression of Ang II that could be related to a lower response to this vasoconstrictor. An increase in the expression of B1 would improve vasodilation, which would be a beneficial effect of combined therapies for hypertension.

Comparison between In Vitro Antiviral Effect of Mexican Propolis and Three Commercial Flavonoids against Canine Distemper Virus.

Propolis is a resin that honey bees (Apis mellifera) produce by mixing wax, exudates collected from tree shoots, pollen, and enzymes. It has been used for its biological properties against pathogenic microorganisms including those of viral origin. In the present study, we demonstrate the antiviral effect of Mexican propolis, as well as of the three commercial flavonoids (quercetin, naringenin, and pinocembrin) present in its composition, in cell cultures infected with Canine Distemper Virus. The treatments were carried out with propolis, flavonoids individually, and a mixture of the three flavonoids at three different times. Antiviral activity was evaluated by the inhibition of the relative expression of the virus nucleoprotein gene (Real-Time qPCR) and by the determination of cellular viability (MTT assay). Propolis applied before infection decreased viral expression (0.72 versus 1.0, 1.65, and 1.75 relative expressions) and correlated with increased cell viability (0.314 versus 0.215, 0.259, and 0.237 absorbance units (AU)). The administration of a flavonoid mixture containing the three commercial flavonoids before infection induces a slight decrease in viral expression (0.93 versus 1, 1.42, and 1.82 relative expressions); however, it does not improve cellular viability (0.255 versus 0.247, 0.282, and 0.245 AU). Quercetin administrated at the same time of infection decreases viral expression (0.90 versus 1.0, 3.25, and 1.02 relative expressions) and improves cellular viability (0.294 versus 0.240, 0.250, and 0.245 AU). Pinocembrin and naringenin individually did not show any antiviral activity at the administration times evaluated in this study. The present work is the first in vitro study of the effect of propolis in Canine Distemper Virus and demonstrated the antiviral activity of Mexican propolis, in addition to the synergy that exists between the three flavonoids on cell viability and the expression of the nucleoprotein virus gene.

Association of Single-Nucleotide Polymorphisms in Immune-Related Genes with Development of Dengue Hemorrhagic Fever in a Mexican Population.

Single-nucleotide polymorphisms (SNPs) occurring in immune-related genes have been associated with risk or protection for development of dengue, depending on ethnicity. Here, we genotyped seven SNPs located in immune response-related genes to identify their association with severe forms of dengue in patients from an endemic region in Mexico. One hundred and thirty-eight patients with dengue fever (DF), thirty-one dengue hemorrhagic fever (DHF) patients, as well as 304 healthy donors were genotyped by using a TaqMan-based approach. SNP analysis, including rs1800629 (TNF), rs4804803 (CD209), rs2780831 (JAK1), rs1801274 (FCGR2A), rs231775 (CTLA4), rs12979860, and rs8099917 (IFNL3), was performed. The rs1800629 A-allele in the TNF gene was associated with an increased risk of DHF (OR = 3.4, CI = 1.235-9.284 p = 0.0212) whereas SNPs rs4804803, rs2780831, rs1801274, rs231775, rs12979860, and rs8099917 showed no association in this cohort. These results show that allelic variations in TNF can play an important role in the development of DHF. However, the lack of association between all remaining SNPs and DHF suggests that the genetic background might directly modify the role of these immune-related molecules, leading to the milder illness often observed in a Mexican population.

Hepatitis C virus molecular evolution: transmission, disease progression and antiviral therapy.

Hepatitis C virus (HCV) infection represents an important public health problem worldwide. Reduction of HCV morbidity and mortality is a current challenge owned to several viral and host factors. Virus molecular evolution plays an important role in HCV transmission, disease progression and therapy outcome. The high degree of genetic heterogeneity characteristic of HCV is a key element for the rapid adaptation of the intrahost viral population to different selection pressures (e.g., host immune responses and antiviral therapy). HCV molecular evolution is shaped by different mechanisms including a high mutation rate, genetic bottlenecks, genetic drift, recombination, temporal variations and compartmentalization. These evolutionary processes constantly rearrange the composition of the HCV intrahost population in a staging manner. Remarkable advances in the understanding of the molecular mechanism controlling HCV replication have facilitated the development of a plethora of direct-acting antiviral agents against HCV. As a result, superior sustained viral responses have been attained. The rapidly evolving field of anti-HCV therapy is expected to broad its landscape even further with newer, more potent antivirals, bringing us one step closer to the interferon-free era.

Vertical transmission of hepatitis C virus: a tale of multiple outcomes.

Globally, hepatitis C virus (HCV) infection affects approximately 130 million people and 3 million new infections occur annually. HCV is also recognized as an important cause of chronic liver disease in children. The absence of proofreading properties of the HCV RNA polymerase leads to a highly error prone replication process, allowing HCV to escape host immune response. The adaptive nature of HCV evolution dictates the outcome of the disease in many ways. Here, we investigated the molecular evolution of HCV in three unrelated children who acquired chronic HCV infection as a result of mother-to-child transmission, two of whom were also coinfected with HIV-1. The persistence of discrete HCV variants and their population structure were assessed using median joining network and Bayesian approaches. While patterns of viral evolution clearly differed between subjects, immune system dysfunction related to HIV coinfection or persistent HCV seronegativity stand as potential mechanisms to explain the lack of molecular evolution observed in these three cases. In contrast, treatment of HCV infection with PegIFN, which did not lead to sustained virologic responses in all 3 cases, was not associated with commensurate variations in the complexity of the variant spectrum. Finally, the differences in the degree of divergence suggest that the mode of transmission of the virus was not the main factor driving viral evolution.