María Martell

Transmission of Hepatitis C Virus by a Cardiac Surgeon

BACKGROUND In the course of a study conducted in 1992 through 1994 of the efficacy of screening blood donors for antibodies to hepatitis C virus (HCV), we found that two patients had acquired hepatitis C after cardiac surgery, with the transmission apparently unrelated to blood transfusions. Because their surgeon had chronic hepatitis C, we sought to determine whether he was transmitting the virus to his patients. METHODS Of 222 of the surgeons patients who participated in studies of post-transfusion hepatitis between 1988 and 1994, 6 contracted postoperative hepatitis C, despite the use of only seronegative blood for transfusions. All six patients had undergone valve-replacement surgery. Analyses were performed to compare nucleotide sequences encompassing the hypervariable region at the junction between the coding regions for envelope glycoproteins E1 and E2 in the surgeon, the patients, and 10 controls infected with the same HCV genotype. RESULTS The surgeon and five of the six patients with hepatitis C unrelated to transfusion were infected with HCV genotype 3; the sixth patient had genotype 1 and was considered to have been infected from another source. Thirteen other patients of the surgeon had transfusion-associated hepatitis C and were also infected with genotype 1. The average net genetic distance between the sequences from the five patients with HCV genotype 3 and those from the surgeon was 2.1 percent (range, 1.1 to 2.5 percent; P < 0.001), as compared with an average distance of 7.6 percent (range, 6.1 to 8.3 percent) between the sequences from the patients and those from the controls. The results of phylogenetic-tree analysis indicated a common epidemiologic origin of the viruses from the surgeon and the five patients. CONCLUSIONS Our findings provide evidence that a cardiac surgeon with chronic hepatitis C may have transmitted HCV to five of his patients during open-heart surgery.

Nucleotide and Amino Acid Complexity of Hepatitis C Virus Quasispecies in Serum and Liver

ABSTRACT The quasispecies nature of the hepatitis C virus (HCV) is thought to play a central role in maintaining and modulating viral replication. Several studies have tried to unravel, through the parameters that characterize HCV circulating quasispecies, prognostic markers of the disease. In a previous work we demonstrated that the parameters of circulating viral quasispecies do not always reflect those of the intrahepatic virus. Here, we have analyzed paired serum and liver quasispecies from 39 genotype 1b-infected patients with different degrees of liver damage, ranging from minimal changes to cirrhosis. Viral level was quantified by real-time reverse transcription-PCR, and viral heterogeneity was characterized through the cloning and sequencing of 540 HCV variants of a genomic fragment encompassing the E2-NS2 junction. Although in 95% of patients, serum and liver consensus HCV amino acid sequences were identical, quasispecies complexity varied considerably between the viruses isolated from each compartment. Patients with HCV quasispecies in serum more complex (26%) than, less complex (28%) than, or similarly complex (41%) to those in liver were found. Among the last, a significant correlation between fibrosis and all the parameters that measure the viral amino acid complexity was found. Correlation between fibrosis and serum viral load was found as well (R = 0.7). With regard to the origin of the differences in quasispecies complexity between serum and liver populations, sequence analysis argued against extrahepatic replication as a quantitatively important contributing factor and supported the idea of a differential effect or different selective forces on the virus depending on whether it is circulating in serum or replicating in the liver.

Physiopathology of splanchnic vasodilation in portal hypertension

In liver cirrhosis, the circulatory hemodynamic alterations of portal hypertension significantly contribute to many of the clinical manifestations of the disease. In the physiopathology of this vascular alteration, mesenteric splanchnic vasodilation plays an essential role by initiating the hemodynamic process. Numerous studies performed in cirrhotic patients and animal models have shown that this splanchnic vasodilation is the result of an important increase in local and systemic vasodilators and the presence of a splanchnic vascular hyporesponsiveness to vasoconstrictors. Among the molecules and factors known to be potentially involved in this arterial vasodilation, nitric oxide seems to have a crucial role in the physiopathology of this vascular alteration. However, none of the wide variety of mediators can be described as solely responsible, since this phenomenon is multifactorial in origin. Moreover, angiogenesis and vascular remodeling processes also seem to play a role. Finally, the sympathetic nervous system is thought to be involved in the pathogenesis of the hyperdynamic circulation associated with portal hypertension, although the nature and extent of its role is not completely understood. In this review, we discuss the different mechanisms known to contribute to this complex phenomenon.

Detection of early portal hypertension with routine data and liver stiffness in patients with asymptomatic liver disease: A prospective study

BACKGROUND & AIMS Detecting portal hypertension (PH) before the development of varices is important for prognosis and for designing interventional studies. None of the available strategies is used in practice. We evaluated a sequential screening-diagnostic strategy based on clinical data and transient elastography (TE) to detect PH in asymptomatic outpatients with liver disease. METHODS Consecutive patients with chronic liver disease and no previous diagnosis of PH were screened by TE. Patients with liver stiffness (LS) ⩾ 13.6 kPa were further evaluated by endoscopy and hepatic venous pressure gradient (HVPG). For analysis, patients were classified in 3 groups: group A, platelets ⩾ 150,000/mm(3), normal abdominal ultrasound; group B, platelets <150,000/mm(3), normal ultrasound; group C, platelets <150,000/mm(3), abnormal ultrasound (splenomegaly, nodular liver surface). RESULTS 250 patients were evaluated (69% group A, 20% group B, 11% group C). In 9% elastography was non-valid. LS ⩾ 13.6 was found in 54 patients (8% A, 43% B, and 81% C, p<0.001). Endoscopy was performed in 49 of these: 20% had small varices, 0% high-risk varices. No patients from group A had varices, and 90% with varices belonged to group C. HVPG was obtained in 40 patients: 93% had PH (HVPG >5 mmHg) and 65% clinically significant PH (CSPH, HVPG ⩾ 10). Only 3 patients, all from group A, had HVPG <5. All patients from groups B and C with LS ⩾ 13.6 had PH. The LS 25 cut-off was excellent at ruling-in CSPH. CONCLUSIONS A simple strategy based on routine clinical data and TE could be useful to detect early PH among asymptomatic patients with chronic liver disease.

Effect of bottlenecking on evolution of the nonstructural protein 3 gene of hepatitis C virus during sexually transmitted acute resolving infection.

ABSTRACT Sexual partners of patients infected with the hepatitis C virus (HCV) often have detectable HCV-specific T-cell responses in the absence of seroconversion, suggesting unapparent, spontaneously resolving infection. To determine whether differences in the evolutionary potential of bottlenecked inoculum may explain the low rate of HCV persistence after sexual exposure, we have investigated changes in the entire HCV nonstructural 3 (NS3) gene over time in a chronic carrier and compared his viral quasispecies with that of the acute-phase isolate of his sexual partner, who developed acute resolving hepatitis C. The overall rate of accumulation of mutations, estimated by regression analysis of six consecutive consensus NS3 sequences over 8 years, was 1.5 × 10−3 mutations per site per year, with small intersample fluctuations related to changes in environmental conditions. Comparison of quasispecies parameters in one isolate of the chronic carrier with those of the acute-phase isolate of the infected partner revealed a higher heterogeneity and lower proportion of nonsynonymous mutations in the former. All NS3 sequences from the acute-phase isolate clustered with a single sequence from the chronic isolate, despite complete HLA mismatch between the patients, suggesting bottlenecking during transmission. The low risk of viral persistence after sexual exposure to HCV may be related to the selection of a limited number of viral particles carrying a particular combination of mutations which may further limit the potential of a relatively homogeneous quasispecies to rapidly diversify and overcome the immune response of the exposed host.

Down-regulation of genes related to the adrenergic system may contribute to splanchnic vasodilation in rat portal hypertension☆

BACKGROUND/AIMS Splanchnic vasodilation initiates the hyperdynamic syndrome in portal hypertension. We aimed to explore molecular mechanisms involved in the development of mesenteric vasodilation in portal hypertension. METHODS Superior mesenteric artery (SMA) samples from portal vein ligated (PVL) and sham rats were compared in a time course experiment using DNA microarrays. Selected genes were quantified by qRT-PCR in PVL and cirrhotic rats. Inmunohistochemistry of tyrosine hydroxylase (Th) and norepinephrine was assessed in SMA sections of PVL and sham rats. Western blot analysis of Th, dopamine beta-hydroxylase (Dbh) and synaptosome-associated protein (Snap-25) was performed in SMA and jejunum samples from the animal models. RESULTS Fifty differentially expressed genes implicated in neurotransmission, especially adrenergic, were detected in SMA samples from PVL rats. Sequential analysis showed a profound down-regulation at 14 days in PVL rats. These down-regulated genes were confirmed by RT-PCR in SMA from PVL and cirrhotic rats. Th and NE detection by immunohistochemistry was reduced in PVL compared to sham. Th, Dbh and Snap-25 expression was lower in SMA from 14-day PVL and cirrhotic rats compared to sham and control rats, respectively. CONCLUSIONS Genetic down-regulation of genes related to the adrenergic system might have a role in splanchnic vasodilation of portal hypertension.

Longitudinal Evaluation of the Structure of Replicating and Circulating Hepatitis C Virus Quasispecies in Nonprogressive Chronic Hepatitis C Patients

ABSTRACT In previous cross-sectional studies, we demonstrated that, in most patients with chronic hepatitis C, the composition and complexity of the circulating hepatitis C virus (HCV) population do not coincide with those of the virus replicating in the liver. In the subgroup of patients with similar complexities in both compartments, the ratio of quasispecies complexity in the liver to that in serum (liver/serum complexity ratio) of paired samples correlated with disease stage. In the present study we investigated the dynamic behavior of viral population parameters in consecutive paired liver and serum samples, obtained 3 to 6 years apart, from four chronic hepatitis C patients with persistently normal transaminases and stable liver histology. We sequenced 359 clones of a genomic fragment encompassing the E2(p7)-NS2 junction, in two consecutive liver-serum sample pairs from the four patients and in four intermediate serum samples from one of the patients. The results show that the liver/serum complexity ratio is not stable but rather fluctuates widely over time. Hence, the liver/serum complexity ratio does not identify a particular group of patients but a particular state of the infecting quasispecies. Phylogenetic analysis and signature mutation patterns showed that virtually all circulating sequences originated from sequences present in the liver specimens. The overall behavior of the circulating viral quasispecies appears to originate from changes in the relative replication kinetics of the large mutant spectrum present in the infected liver.

Sexual Transmission of Hepatitis C Virus From a Patient With Chronic Disease to His Sex Partner After Removal of an Intrauterine Device

Background Approximately 40% of patients infected with hepatitis C virus (HCV) have no history of blood transfusion or other high-risk practice. Other causes should be considered. Goal The goal was to describe sexual transmission of HCV from a chronic carrier to his female partner during unprotected vaginal intercourse after removal of an intrauterine device. Study Design A heterosexual woman who was a regular blood donor acquired acute HCV infection from her sex partner, who was chronically infected. The study included an interview and phylogenetic analysis of sequences of virus obtained from the couple. Results Risk factors other than vaginal sexual relations with her partner were ruled out. Phylogenetic analysis showed that sequences from the couple clustered together in all trees generated, in comparison with local and GenBank controls. Conclusion The temporal relationship between removal of the intrauterine device and the acute hepatitis suggests that vaginal mucosal damage might have favored transmission of HCV. Barrier precautions should be suggested whenever damage of the vaginal tract has occurred.

Atrophy of mesenteric sympathetic innervation may contribute to splanchnic vasodilation in rat portal hypertension

Background and aims: Portal hypertension is associated with downregulation of mRNA and proteins involved in adrenergic transmission in the superior mesenteric artery (SMA) in portal vein‐ligated (PVL) and cirrhotic rats. We aimed to investigate whether SMA adrenergic dysfunction was accompanied by sympathetic nerve structural changes and whether it was extensive to resistance mesenteric arteries. We also attempted to localize the origin of mRNA of specific adrenergic genes.

Large accumulation of mRNA and DNA point modifications in a plant senescent tissue

Although nucleic acids are the paradigm of genetic information conservation, they are inherently unstable molecules that suffer intrinsic and environmental damage. Oxidative stress has been related to senescence and aging and, recently, it has been shown that mutations accumulate at high frequency in mitochondrial DNA with age. We investigated RNA and DNA modifications in cork, a senescent plant tissue under high endogenous oxidative stress conditions. When compared to normally growing young tissue, cork revealed an unexpected high frequency of point modifications in both cDNA (Pn=1/1784) and nuclear DNA (Pn=1/1520). Cork should be viewed as a mosaic of genetically heterogeneous cells. This has biological implications: it supports somatic mutation models for aging and challenges ‘single cDNA clone’ as descriptor for the molecular genetics of senescent tissues.