Ana Rosa Rincón-Sánchez

Acetylsalicylic acid inhibits hepatitis C virus RNA and protein expression through cyclooxygenase 2 signaling pathways

It has been reported that salicylates (sodium salicylate and aspirin) inhibit the replication of flaviviruses, such as Japanese encephalitis virus and dengue virus. Therefore, we considered it important to test whether acetylsalicylic acid (ASA) had anti–hepatitis C virus (HCV) activity. To this end, we examined the effects of ASA on viral replication and protein expression, using an HCV subgenomic replicon cell culture system. We incubated Huh7 replicon cells with 2‐8 mM ASA for different times and measured HCV‐RNA and protein levels by northern blot, real‐time polymerase chain reaction, and western analysis, respectively. We found that ASA had a suppressive effect on HCV‐RNA and protein levels (nearly 58%). ASA‐dependent inhibition of HCV expression was not mediated by the 5′‐internal ribosome entry site or 3′‐untranslated regions, as determined by transfection assays using bicistronic constructs containing these regulatory regions. However, we found that HCV‐induced cyclooxygenase 2 (COX‐2) messenger RNA and protein levels and activity and these effects were down‐regulated by ASA, possibly by a nuclear factor kappa B–independent mechanism. We also observed that the ASA‐dependent inhibition of viral replication was due in part to inhibition of COX‐2 and activation of p38 and mitogen‐activated protein kinase/extracellular signal‐regulated kinase kinase 1/2 (MEK1/2) mitogen‐activated protein kinases (MAPKs). Inhibition of these kinases by SB203580 and U0126, respectively, and by short interfering RNA silencing of p38 and MEK1 MAPK prevented the antiviral effect of ASA. Taken together, our findings suggest that the anti‐HCV effect of ASA in the Huh7 replicon cells is due to its inhibitory effect on COX‐2 expression, which is mediated in part by the activation of MEK1/2/p38 MAPK. Conclusion: These findings suggest the possibility that ASA could be an excellent adjuvant in the treatment of chronic HCV infection. (HEPATOLOGY 2008.)

Additive effect of ethanol and HCV subgenomic replicon expression on COX‐2 protein levels and activity

Summary.  The mechanisms by which alcohol exacerbates liver injury in patients with hepatitis C are unknown. We used the hepatitis C virus (HCV) subgenomic replicon cell system to evaluate the effect of ethanol on HCV replication and viral protein synthesis. Our results demonstrate that alcohol stimulates HCV replicon expression at both HCV‐RNA and protein levels. Furthermore, we observed that ethanol treatment showed an additive effect in cyclooxygenase‐2 (COX‐2) protein expression and activity already induced by HCV viral proteins, and in turn increased HCV viral expression. Our results suggest that COX‐2 activity is involved in ethanol‐induced HCV‐RNA and NS5A protein expression, because acetylsalicylic acid (ASA), a COX‐1/2 inhibitor, blocked this induction and downregulated COX‐2 protein expression and activity. Therefore, we suggest that ethanol increases HCV replication expression, at least in part, by upregulating a key cellular regulator of oxidative stress pathway known as COX‐2 or its products.

Cu/Zn superoxide dismutase (SOD1) induction is implicated in the antioxidative and antiviral activity of acetylsalicylic acid in HCV-expressing cells

We evaluated the participation of oxidative stress in the negative regulation of hepatitis C virus (HCV)-RNA induced by acetylsalicylic acid (ASA). We used the HCV subgenomic replicon cell system that stably expresses HCV-nonstructural proteins (Huh7 HCV replicon cells) and the parental cell line. Cells were exposed to 4 mM ASA at different times (12-72 h), and pyrrolidine dithiocarbamate (PDTC) was used as an antioxidant control. Reactive oxygen species (ROS) production, oxidized protein levels, cytosolic superoxide dismutase (Cu/Zn-SOD), and glutathione peroxidase (GPx) activity were measured to evaluate oxidative stress. In addition, viral RNA and prostaglandin (PGE(2)) levels were determined. We observed that ASA treatment decreased ROS production and oxidized protein levels in a time-dependent fashion in both parental and HCV replicon cells with a greater extent in the latter. Similar results were found with PDTC exposure. Average GPx activity was decreased, whereas a striking increase was observed in average cytosolic SOD activity at 48 and 72 h in both cells exposed to ASA, compared with untreated cells. HCV replicon cells showed higher levels of Cu/Zn-SOD expression (mRNA and protein) with ASA treatment (48 and 72 h), whereas NS5A protein levels showed decreased expression. In addition, we found that inhibition of SOD1 expression reversed the effect of ASA. Interestingly, PDTC downregulated HCV-RNA expression (55%) and PGE(2) (60%) levels, imitating ASA exposure. These results suggest that ASA treatment could reduce cellular oxidative stress markers and modify Cu/Zn-SOD expression, a phenomenon that may contribute to the mechanisms involved in HCV downregulation.

The role of dystroglycan in PDGF-BB-dependent migration of activated hepatic stellate cells/myofibroblasts

Hepatic stellate cells are embedded in the loose connective tissue matrix within the space of Disse. This extracellular matrix contains several basement membrane components including laminin, but its composition changes during liver injury because of the production of extracellular matrix components found in scar tissue. These changes in extracellular matrix composition and in cell-extracellular matrix interactions may play a key role in hepatic stellate cell transdifferentiation. In this communication we used early passages of mouse hepatic stellate cells (activated HSC/myofibroblasts) to study the platelet-derived growth factor BB (PDGF-BB)-dependent expression and regulation of β-dystroglycan and its role in activated HSC/myofibroblast migration. We used Northern and Western analysis to study dystroglycan expression and confocal microscopy to investigate changes in subcellular distribution of the protein. Activated HSC migration was investigated using an in vitro wound-healing assay. PDGF-BB induced significant changes in dystroglycan regulation and subcellular distribution of the protein. Whereas steady-state levels of dystroglycan mRNA remained constant, PDGF-BB increased dystroglycan transcription but shortened the t(1/2) by 50%. Moreover, PDGF-BB changed dystroglycan and α5-integrin cellular distribution. Cell migration experiments revealed that PDGF-BB-dependent migration of activated HSC/myofibroblasts was completely blocked by neutralizing antibodies to fibronectin, α5-integrin, laminin, and β-dystroglycan. Overall, these findings suggest that both laminin and fibronectin and their receptors play a key role in PDGF-BB-induced activated HSC migration.

Beneficial effects of quercetin on oxidative stress in liver and kidney induced by titanium dioxide (TiO2) nanoparticles in rats

Abstract TiO2 nanoparticles used as vectors for the delivery of drugs have shown greater effectiveness. However, TiO2 nanoparticles can cause oxidative stress in liver and kidney, so we analyzed if a previous or simultaneous quercetin treatment could counteract this in rats. Five groups of male Wistar rats (200–250 g) were included: (1) healthy controls, (2) TiO2 group, (3) quercetin group, (4) preventive group: quercetin for 5 days prior to exposure of TiO2, and (5) therapeutic group: TiO2 (5 mg/kg, i.v.) plus quercetin single dose for 5 days (5 mg/kg/day, i.p.). Hepatic and renal function tests were made. Five animals from each group were sacrificed (0, 14 and 28 days), and liver and kidney tissue were obtained. Malondialdehyde (MDA), reduced/oxidized glutathione, and activity of glutathione peroxidase/reductase were measured, as well as the level of gene expression by q-PCR. There were no significant changes in serum ALT and AST activities. More damage was observed at 14 versus 28 days, because TiO2 was excreted in urine. Quercetin indeed showed a renal protective effect by increasing glutathione reductase and peroxidase levels and reducing MDA levels. On the other hand, TiO2 liver damage was less pronounced with quercetin as therapeutic treatment. TiO2 induces significantly the glutathione reductase expression and it can be down-regulated by quercetin. Biochemical tests in serum and urine showed a better effect of quercetin administered in the therapeutic group. Care should be taken with the dose and time of administration of quercetin, because this antioxidant could also have a pro-oxidant effect.

Hepatoprotective Effect of Opuntia robusta and Opuntia streptacantha Fruits against Acetaminophen-Induced Acute Liver Damage

Acetaminophen (APAP)-induced acute liver failure (ALF) is a serious health problem in developed countries. N-acetyl-l-cysteine (NAC), the current therapy for APAP-induced ALF, is not always effective, and liver transplantation is often needed. Opuntia spp. fruits are an important source of nutrients and contain high levels of bioactive compounds, including antioxidants. The aim of this study was to evaluate the hepatoprotective effect of Opuntia robusta and Opuntia streptacantha extracts against APAP-induced ALF. In addition, we analyzed the antioxidant activities of these extracts. Fruit extracts (800 mg/kg/day, orally) were given prophylactically to male Wistar rats before intoxication with APAP (500 mg/kg, intraperitoneally). Rat hepatocyte cultures were exposed to 20 mmol/L APAP, and necrosis was assessed by LDH leakage. Opuntia robusta had significantly higher levels of antioxidants than Opuntia streptacantha. Both extracts significantly attenuated APAP-induced injury markers AST, ALT and ALP and improved liver histology. The Opuntia extracts reversed APAP-induced depletion of liver GSH and glycogen stores. In cultured hepatocytes, Opuntia extracts significantly reduced leakage of LDH and cell necrosis, both prophylactically and therapeutically. Both extracts appeared to be superior to NAC when used therapeutically. We conclude that Opuntia extracts are hepatoprotective and can be used as a nutraceutical to prevent ALF.

MIF and TNFα serum levels in rheumatoid arthritis patients treated with disease-modifying antirheumatic drugs: a cross-sectional study

Abstract Macrophage migration inhibitory factor (MIF) and tumor necrosis factor alpha (TNFα) play a pivotal role in rheumatoid arthritis (RA). MIF is considered a relevant cytokine because it appears before TNFα in the inflammatory cascade thus stimulating TNFα production and MIF’s relationship with traditional synthetic disease modifying antirheumatic drugs (sDMARDs) is unknown. In this cross-sectional study, we investigated the association of MIF and TNFα serum levels with methotrexate (MTX) and in combination with chloroquine (CLQ) and sulfasalazine (SSZ) in RA patients classified according to the ACR/EULAR 2010 criteria. Patients were divided into three groups: MTX-monotherapy group (n = 40), MTX combination therapy groups: MTX + CLQ (n = 41), and MTX + CLQ + SSZ (n = 42). MIF and TNFα serum levels were determined by ELISA. We found high levels of ESR, CRP, RF, and anti-CCP in all therapy groups. Furthermore, we subclassified 97 patients with established RA (≥2 years of disease duration) and found that TNFα serum levels were lower in the combination therapy group (MTX + CLQ + SSZ) in comparison with the monotherapy MTX group (16.7 pg/mL versus 13.6 pg/mL, p = 0.02). However, we did not find differences between sDMARD therapies in MIF serum levels. We did find a significant reduction in MIF serum levels in patients treated with oral steroids compared with patients without oral steroids (1.7 ng/mL versus 4.3 ng/mL, p < 0.001). In conclusion, this study supports the role of sDMARDs in modifying TNFα serum levels and oral steroids MIF serum levels. Nevertheless, we found that MIF serum levels are not modified by sDMARD treatment.

Natural Dietary Pigments: Potential Mediators against Hepatic Damage Induced by Over-The-Counter Non-Steroidal Anti-Inflammatory and Analgesic Drugs

Over-the-counter (OTC) analgesics are among the most widely prescribed and purchased drugs around the world. Most analgesics, including non-steroidal anti-inflammatory drugs (NSAIDs) and acetaminophen, are metabolized in the liver. The hepatocytes are responsible for drug metabolism and detoxification. Cytochrome P450 enzymes are phase I enzymes expressed mainly in hepatocytes and they account for ≈75% of the metabolism of clinically used drugs and other xenobiotics. These metabolic reactions eliminate potentially toxic compounds but, paradoxically, also result in the generation of toxic or carcinogenic metabolites. Cumulative or overdoses of OTC analgesic drugs can induce acute liver failure (ALF) either directly or indirectly after their biotransformation. ALF is the result of massive death of hepatocytes induced by oxidative stress. There is an increased interest in the use of natural dietary products as nutritional supplements and/or medications to prevent or cure many diseases. The therapeutic activity of natural products may be associated with their antioxidant capacity, although additional mechanisms may also play a role (e.g., anti-inflammatory actions). Dietary antioxidants such as flavonoids, betalains and carotenoids play a preventive role against OTC analgesics-induced ALF. In this review, we will summarize the pathobiology of OTC analgesic-induced ALF and the use of natural pigments in its prevention and therapy.

Prevalence of Potential Drug-Drug Interactions in Hospitalized Surgical Patients

The objective of this study is to estimate the prevalence and describe the characteristics of pDDIs (potential drug-drug interactions) in medical prescriptions of hospitalized surgical patients. In this cross-sectional study, we analyzed 370 medical prescriptions from the surgery unit of a Mexican public teaching hospital. The identification and classification of potential drug-drug interactions were performed with the Micromedex 2.0 electronic drug information database. Results were analyzed with descriptive statistics and we estimated OR (odds ratio) to determine associated risk factors. From the study, it was found that the prevalence of potential drug-drug interactions was 45.9%. A total of 385 interactions were identified. Of these, 54.3% were classified as major and 60.5% as pharmacodynamic. Prescriptions for more than seven drugs (OR =7.33, CI (confidence interval) = 4.59~11.71) and advanced age > 60 years, (OR = 1.79, CI = 1.06~2.74) were positively associated with the presence of potential drug-drug interactions. We found a high prevalence of clinically relevant pDDIs in the surgery unit. In view of this outcome, the safety of drug combinations in hospitalized surgical patients should be evaluated during the prescription process in order to prevent adverse events.

Ehlers-Danlos Syndrome Type VIIC: A Mexican Case Report

Ehlers-Danlos syndrome (EDS) is a heterogeneous group of heritable connective tissue disorders whose primary clinical features include soft and extensible skin, articular hypermobility and tissue fragility. EDS type VIIC or ‘human dermatosparaxis’ is an autosomal recessive disease characterized by severe skin fragility and sagging redundant skin (major criteria) with a soft, doughy texture, easy bruising, premature rupture of fetal membranes and large hernias (minor criteria). Dermatosparaxis (meaning ‘tearing of skin’), which has been described in several non-human species, is a disorder of the connective tissue resulting from a deficiency of the enzyme that cleaves the registration peptide off the N-terminal end of collagen after it has been secreted from fibroblasts. We describe a Mexican case from consanguineous parents with all the phenotypical characteristics previously described, plus skeletal abnormalities.