PACKMOL: a package for building initial configurations for molecular dynamics simulations

Adequate initial configurations for molecular dynamics simulations consist of arrangements of molecules distributed in space in such a way to approximately represent the system's overall structure. In order that the simulations are not disrupted by large van der Waals repulsive interactions, atoms from different molecules must keep safe pairwise distances. Obtaining such a molecular arrangement can be considered a packing problem: Each type molecule must satisfy spatial constraints related to the geometry of the system, and the distance between atoms of different molecules must be greater than some specified tolerance. We have developed a code able to pack millions of atoms, grouped in arbitrarily complex molecules, inside a variety of three-dimensional regions. The regions may be intersections of spheres, ellipses, cylinders, planes, or boxes. The user must provide only the structure of one molecule of each type and the geometrical constraints that each type of molecule must satisfy. Building complex mixtures, interfaces, solvating biomolecules in water, other solvents, or mixtures of solvents, is straightforward. In addition, different atoms belonging to the same molecule may also be restricted to different spatial regions, in such a way that more ordered molecular arrangements can be built, as micelles, lipid double-layers, etc. The packing time for state-of-the-art molecular dynamics systems varies from a few seconds to a few minutes in a personal computer. The input files are simple and currently compatible with PDB, Tinker, Molden, or Moldy coordinate files. The package is distributed as free software and can be downloaded from http://www.ime.unicamp.br/~martinez/packmol/.

Drug-induced liver injury: an analysis of 461 incidences submitted to the Spanish registry over a 10-year period

BACKGROUND & AIMS

Progress in the understanding of susceptibility factors to drug-induced liver injury (DILI) and outcome predictability are hampered by the lack of systematic programs to detect bona fide cases.

METHODS

A cooperative network was created in 1994 in Spain to identify all suspicions of DILI following a prospective structured report form. The liver damage was characterized according to hepatocellular, cholestatic, and mixed laboratory criteria and to histologic criteria when available. Further evaluation of causality assessment was centrally performed.

RESULTS

Since April 1994 to August 2004, 461 out of 570 submitted cases, involving 505 drugs, were deemed to be related to DILI. The antiinfective group of drugs was the more frequently incriminated, amoxicillin-clavulanate accounting for the 12.8% of the whole series. The hepatocellular pattern of damage was the most common (58%), was inversely correlated with age (P < .0001), and had the worst outcome (Cox regression, P < .034). Indeed, the incidence of liver transplantation and death in this group was 11.7% if patients had jaundice at presentation, whereas the corresponding figure was 3.8% in nonjaundiced patients (P < .04). Factors associated with the development of fulminant hepatic failure were female sex (OR = 25; 95% CI: 4.1-151; P < .0001), hepatocellular damage (OR = 7.9; 95% CI: 1.6-37; P < .009), and higher baseline plasma bilirubin value (OR = 1.15; 95% CI: 1.09-1.22; P < .0001).

CONCLUSIONS

Patients with drug-induced hepatocellular jaundice have 11.7% chance of progressing to death or transplantation. Amoxicillin-clavulanate stands out as the most common drug related to DILI.

EASL Clinical Practice Guidelines: Drug-induced liver injury

Idiosyncratic (unpredictable) drug-induced liver injury is one of the most challenging liver disorders faced by hepatologists, because of the myriad of drugs used in clinical practice, available herbs and dietary supplements with hepatotoxic potential, the ability of the condition to present with a variety of clinical and pathological phenotypes and the current absence of specific biomarkers. This makes the diagnosis of drug-induced liver injury an uncertain process, requiring a high degree of awareness of the condition and the careful exclusion of alternative aetiologies of liver disease. Idiosyncratic hepatotoxicity can be severe, leading to a particularly serious variety of acute liver failure for which no effective therapy has yet been developed. These Clinical Practice Guidelines summarize the available evidence on risk factors, diagnosis, management and risk minimization strategies for drug-induced liver jury.

A G protein couples serotonin and GABAB receptors to the same channels in hippocampus

Both serotonin and the selective gamma-aminobutyric acidB (GABAB) agonist, baclofen, increase potassium (K+) conductance in hippocampal pyramidal cells. Although these agonists act on separate receptors, the potassium currents evoked by the agonists are not additive, indicating that the two receptors share the same potassium channels. Experiments with hydrolysis-resistant guanosine triphosphate (GTP) and guanosine diphosphate analogs and pertussis toxin indicate that the opening of the potassium channels by serotonin and GABAB receptors involves a pertussis toxin-sensitive GTP-binding (G) protein, which may directly couple the two receptors to the potassium channel.

Insulin resistance impairs sustained response rate to peginterferon plus ribavirin in chronic hepatitis C patients

BACKGROUND & AIMS

We evaluated the effect of insulin resistance and viral factors on sustained virological response in patients with chronic hepatitis C treated with peginterferon plus ribavirin.

METHODS

Patients (n=159; 94 men; age, 41.7 +/- 11.1 years) with chronic hepatitis C (genotype 1, n=113; non-1 genotype, n=46) received treatment with interferon plus ribavirin. Serum levels of leptin and insulin were measured, and the insulin resistance index (HOMA-IR: homeostasis model of assessment) and body mass index were calculated.

RESULTS

A sustained virological response was associated with lower age, insulin resistance index, body mass index, and gamma-glutamyltranspeptidase and serum leptin levels. There was no association with viral load, sex, type of interferon, or cholesterol levels. A sustained virological response was achieved in 43.4% (46/113) of genotype 1 and 89% (32/36) of genotype 2 and 3 (P=.0001) patients. Necroinflammatory activity and steatosis were not associated with the sustained virological response rate. Multivariate regression analysis indicated that the independent variables related to sustained virological response were genotype (odds ratio, 3.57; 95% confidence interval, 1.49-8.3; P=.001), insulin resistance index (odds ratio, 1.82; 95% confidence interval, 1.08-3.06; P=.012), and fibrosis (odds ratio, 1.36; 95% confidence interval, 1.01-1.84; P=.029). A sustained virological response in patients with genotype 1 and insulin resistance (HOMA-IR > 2) occurred in 23 of 70 (32.8%; 95% confidence interval, 21.9%-43.9%) patients, vs. 26 of 43 (60.5%; 95% confidence interval, 45.9%-75.1%) genotype 1 patients without insulin resistance (P=.007; odds ratio, 3.12, 95% confidence interval, 1.42-6.89).

CONCLUSIONS

Insulin resistance, fibrosis, and genotype are independent predictors of the response to antiviral therapy in chronic hepatitis C patients treated with peginterferon plus ribavirin.

5-Hydroxytryptamine2 and 5-hydroxytryptamine 1A receptors mediate opposing responses on membrane excitability in rat association cortex

The effects of serotonin on pyramidal cells of layer V of the medial prefrontal cortex were examined using intracellular recording techniques in rat brain slices in vitro. Bath administration of serotonin (0.3-100 microM) produced two distinct responses which could be differentiated physiologically and pharmacologically. The first of these responses was a membrane hyperpolarization. This effect of serotonin was associated with a decrease in input resistance and was independent of the transmembrane chloride gradient, suggesting that it was mediated by an increase in potassium conductance. The ability of serotonin to induce a hyperpolarization was mimicked by (+/-)-8-hydroxy-dipropylaminotetralin hydrobromide and was blocked by BMY 7378 and spiperone but not by ketanserin, indicating that it was mediated by the activation of receptors of the 5-hydroxytryptamine1A subtype. The second response to serotonin involved a membrane depolarization, the replacement of the afterhyperpolarization that follows a burst of spikes in these cells by a slow depolarizing afterpotential, and a decrease in spike frequency accommodation. These effects were mimicked by 4-bromo-2,5-dimethoxyphenyl-isopropylamine and antagonized by ketanserin and by low concentrations of spiperone, indicating that they were mediated by the activation of 5-hydroxytryptamine2 receptors. Interestingly, qualitatively identical responses could be elicited in these cells by activation of muscarinic and alpha 1-adrenergic receptors suggesting that 5-hydroxytryptamine2, muscarinic and alpha 1-adrenergic receptors converge onto a common set of membrane mechanisms to increase cellular excitability. Although 5-hydroxytryptamine1A and 5-hydroxytryptamine2 receptors mediated opposing effects on membrane excitability, most pyramidal neurons appeared to express both receptor subtypes on their membrane surface. The coactivation of both receptor subtypes resulted in a selective enhancement of responsiveness to strong excitatory stimuli with little effect on weaker stimuli. The paradoxical presence of two serotonin receptors mediating opposite effects on membrane excitability in the same cell provides a flexible mechanism by which serotonin might regulate how pyramidal neurons encode incoming excitatory stimuli onto firing activity.

Pharmacologically distinct actions of serotonin on single pyramidal neurones of the rat hippocampus recorded in vitro

1. The actions of serotonin (5-HT) on pyramidal cells of the CA1 region of the rat hippocampus were characterized using intracellular recording in in vitro brain slices. 2. 5-HT typically evokes a biphasic response consisting of a hyperpolarization which is followed by a longer-lasting depolarization. These effects on membrane potential are accompanied by a decrease in the calcium-activated after-hyperpolarization (a.h.p). 3. Detailed analysis using 5-HT antagonists and agonists indicates that the hyperpolarization is mediated by a 5-HT1A receptor. Spiperone is the most effective antagonist of the response and the selective 5-HT1A agonist, 8-OHDPAT, behaves as a partial agonist at this receptor. In agreement with the distribution of 5-HT1A binding sites, responses to 5-HT were most prominent in the stratum radiatum. 4. The hyperpolarizing response is associated with a decrease in input resistance, is blocked by extracellular barium and intracellular caesium, is unaffected by the chloride gradient, and its reversal potential shifts with the extracellular concentration of potassium as predicted for a response mediated by a selective increase in potassium permeability. 5. The depolarizing response and reduction in the a.h.p. could be studied in isolation by blocking the hyperpolarizing response with either pertussis toxin or spiperone. The pharmacology of these responses did not correspond to that of any of the 5-HT binding sites reported in C.N.S. tissue. Although the depolarization and blockade of the a.h.p. have the same time course it is unclear if they are mediated by the same or different receptors. 6. The depolarization most likely results from a decrease in resting potassium conductance. However, neither a blockade of the M current nor the a.h.p. current can account for the depolarization. 7. Blockade of phosphodiesterase activity by 3-isobutyl-1-methylxanthine (IBMX) did not enhance the depressant action of 5-HT on the a.h.p., making it unlikely that this action is mediated by cyclic AMP. 8. Blockade of the a.h.p. by 5-HT reduces spike frequency adaptation and counteracts the inhibitory action of 5-HT on 5-HT1A receptors. This excitatory action outlasts the hyperpolarizing action. 9. In summary 5-HT acts on at least two distinct receptors on hippocampal pyramidal cells, one coupled to the opening of potassium channels and a second coupled to a decrease in a resting potassium conductance and a decrease in the a.h.p.

Incidence and Etiology of Drug-Induced Liver Injury in Mainland China

BACKGROUND & AIMS

We performed a nationwide, retrospective study to determine the incidence and causes of drug-induced liver injury (DILI) in mainland China.

METHODS

We collected data on a total of 25,927 confirmed DILI cases, hospitalized from 2012 through 2014 at 308 medical centers in mainland China. We collected demographic, medical history, treatment, laboratory, disease severity, and mortality data from all patients. Investigators at each site were asked to complete causality assessments for each case whose diagnosis at discharge was DILI (n = 29,478) according to the Roussel Uclaf Causality Assessment Method.

RESULTS

Most cases of DILI presented with hepatocellular injury (51.39%; 95% confidence interval [CI] 50.76-52.03), followed by mixed injury (28.30%; 95% CI 27.73-28.87) and cholestatic injury (20.31%; 95% CI 19.80-20.82). The leading single classes of implicated drugs were traditional Chinese medicines or herbal and dietary supplements (26.81%) and antituberculosis medications (21.99%). Chronic DILI occurred in 13.00% of the cases and, although 44.40% of the hepatocellular DILI cases fulfilled Hy's Law criteria, only 280 cases (1.08%) progressed to hepatic failure, 2 cases underwent liver transplantation (0.01%), and 102 patients died (0.39%). Among deaths, DILI was judged to have a primary role in 72 (70.59%), a contributory role in 21 (20.59%), and no role in 9 (8.82%). Assuming the proportion of DILI in the entire hospitalized population of China was represented by that observed in the 66 centers where DILI capture was complete, we estimated the annual incidence in the general population to be 23.80 per 100,000 persons (95% CI 20.86-26.74). Only hospitalized patients were included in this analysis, so the true incidence is likely to be higher.

CONCLUSIONS

In a retrospective study to determine the incidence and causes of DILI in mainland China, the annual incidence in the general population was estimated to be 23.80 per 100,000 persons; higher than that reported from Western countries. Traditional Chinese medicines, herbal and dietary supplements, and antituberculosis drugs were the leading causes of DILI in mainland China.

Susceptibility to amoxicillin-clavulanate-induced liver injury is influenced by multiple HLA class I and II alleles

BACKGROUND & AIMS

Drug-induced liver injury (DILI), especially from antimicrobial agents, is an important cause of serious liver disease. Amoxicillin-clavulanate (AC) is a leading cause of idiosyncratic DILI, but little is understood about genetic susceptibility to this adverse reaction.

METHODS

We performed a genome-wide association study using 822,927 single nucleotide polymorphism (SNP) markers from 201 White European and US cases of DILI following AC administration (AC-DILI) and 532 population controls, matched for genetic background.

RESULTS

AC-DILI was associated with many loci in the major histocompatibility complex. The strongest effect was with an HLA class II SNP (rs9274407, P=4.8×10(-14)), which correlated with rs3135388, a tag SNP of HLA-DRB1*1501-DQB1*0602 that was previously associated with AC-DILI. Conditioned on rs3135388, rs9274407 is still significant (P=1.1×10(-4)). An independent association was observed in the class I region (rs2523822, P=1.8×10(-10)), related to HLA-A*0201. The most significant class I and II SNPs showed statistical interaction (P=.0015). High-resolution HLA genotyping (177 cases and 219 controls) confirmed associations of HLA-A*0201 (P=2×10(-6)) and HLA-DQB1*0602 (P=5×10(-10)) and their interaction (P=.005). Additional, population-dependent effects were observed in HLA alleles with nominal significance. In an analysis of autoimmune-related genes, rs2476601 in the gene PTPN22 was associated (P=1.3×10(-4)).

CONCLUSIONS

Class I and II HLA genotypes affect susceptibility to AC-DILI, indicating the importance of the adaptive immune response in pathogenesis. The HLA genotypes identified will be useful in studies of the pathogenesis of AC-DILI but have limited utility as predictive or diagnostic biomarkers because of the low positive predictive values.

Peginterferon-alfa2a plus ribavirin for 48 versus 72 weeks in patients with detectable hepatitis C virus RNA at week 4 of treatment

BACKGROUND & AIMS

Patients with chronic hepatitis C who do not respond rapidly to therapy have a low chance of developing a sustained virologic response (SVR) when treated for 48 weeks. This study investigated whether treatment for 72 weeks increases the rate of SVR in patients with detectable hepatitis C virus (HCV)-RNA levels at week 4 of treatment.

METHODS

A total of 510 treatment-naive patients were treated with peginterferon-alfa2a (180 microg/wk) plus ribavirin (800 mg/day). Patients with detectable HCV-RNA levels at week 4 (n = 326) were randomized to complete 48 (group A, n = 165) or 72 weeks (group B, n = 161) of treatment. Patients with undetectable HCV-RNA levels at week 4 (n = 184) were allocated into group C (n = 148) or group D (n = 36), according to HCV genotype and baseline viremia, and treated for 24 or 48 weeks, respectively. All patients were followed-up for 24 weeks after the end of treatment.

RESULTS

The end-of-treatment response rate (61%) was similar in groups A and B, but the SVR rate was higher in group B (45% vs 32% in A; P = .01). In genotype 1-infected patients randomized to group A (n = 149) or B (n = 142), SVR rates were 28% and 44%, respectively (P = .003). The incidence of adverse events was similar in all groups. Treatment discontinuation was more frequent in group B (36%) than in group A (18%) (P = .0004). SVR rates in groups C and D were 79% and 64%, respectively.

CONCLUSIONS

Extension of treatment with peginterferon-alfa2a plus ribavirin from 48 to 72 weeks significantly increases the rate of SVR in patients with detectable viremia at week 4 of treatment.

Drug-induced liver injury: Interactions between drug properties and host factors

Idiosyncratic drug-induced liver injury (DILI) is a common cause for drug withdrawal from the market and although infrequent, DILI can result in serious clinical outcomes including acute liver failure and the need for liver transplantation. Eliminating the iatrogenic "harm" caused by a therapeutic intent is a priority in patient care. However, identifying culprit drugs and individuals at risk for DILI remains challenging. Apart from genetic factors predisposing individuals at risk, the role of the drugs' physicochemical and toxicological properties and their interactions with host and environmental factors need to be considered. The influence of these factors on mechanisms involved in DILI is multi-layered. In this review, we summarize current knowledge on 1) drug properties associated with hepatotoxicity, 2) host factors considered to modify an individuals' risk for DILI and clinical phenotypes, and 3) drug-host interactions. We aim at clarifying knowledge gaps needed to be filled in as to improve risk stratification in patient care. We therefore broadly discuss relevant areas of future research. Emerging insight will stimulate new investigational approaches to facilitate the discovery of clinical DILI risk modifiers in the context of disease complexity and associated interactions with drug properties, and hence will be able to move towards safety personalized medicine.

Use of Hy's law and a new composite algorithm to predict acute liver failure in patients with drug-induced liver injury

BACKGROUND & AIMS

Hy's Law, which states that hepatocellular drug-induced liver injury (DILI) with jaundice indicates a serious reaction, is used widely to determine risk for acute liver failure (ALF). We aimed to optimize the definition of Hy's Law and to develop a model for predicting ALF in patients with DILI.

METHODS

We collected data from 771 patients with DILI (805 episodes) from the Spanish DILI registry, from April 1994 through August 2012. We analyzed data collected at DILI recognition and at the time of peak levels of alanine aminotransferase (ALT) and total bilirubin (TBL).

RESULTS

Of the 771 patients with DILI, 32 developed ALF. Hepatocellular injury, female sex, high levels of TBL, and a high ratio of aspartate aminotransferase (AST):ALT were independent risk factors for ALF. We compared 3 ways to use Hy's Law to predict which patients would develop ALF; all included TBL greater than 2-fold the upper limit of normal (×ULN) and either ALT level greater than 3 × ULN, a ratio (R) value (ALT × ULN/alkaline phosphatase × ULN) of 5 or greater, or a new ratio (nR) value (ALT or AST, whichever produced the highest ×ULN/ alkaline phosphatase × ULN value) of 5 or greater. At recognition of DILI, the R- and nR-based models identified patients who developed ALF with 67% and 63% specificity, respectively, whereas use of only ALT level identified them with 44% specificity. However, the level of ALT and the nR model each identified patients who developed ALF with 90% sensitivity, whereas the R criteria identified them with 83% sensitivity. An equal number of patients who did and did not develop ALF had alkaline phosphatase levels greater than 2 × ULN. An algorithm based on AST level greater than 17.3 × ULN, TBL greater than 6.6 × ULN, and AST:ALT greater than 1.5 identified patients who developed ALF with 82% specificity and 80% sensitivity.

CONCLUSIONS

When applied at DILI recognition, the nR criteria for Hy's Law provides the best balance of sensitivity and specificity whereas our new composite algorithm provides additional specificity in predicting the ultimate development of ALF.

Standardization of nomenclature and causality assessment in drug-induced liver injury: summary of a clinical research workshop

Idiosyncratic drug-induced liver injury (DILI) is an important but relatively infrequent cause of potentially severe acute and chronic liver injury. The aim of this clinical research workshop was to review and attempt to standardize the current nomenclature and terminology used in DILI research. Because DILI is a diagnosis of exclusion, selected elements of the medical history, laboratory tests, and previous reports were proposed to improve causality assessment. Definitions and diagnostic criteria regarding the onset of DILI, evolution of liver injury, risk factors, and mandatory testing versus optional testing for competing causes were reviewed. In addition, the role of intentional and inadvertent rechallenge, liver histology, and host genetic polymorphisms in establishing the diagnosis and prognosis of DILI were reviewed. Consensus was established regarding the need to develop a web-of-knowledge database that provides concise, reliable, and updated information on cases of liver injury due to drugs and herbal and dietary supplements. In addition, the need to develop drug-specific computerized causality assessment methods that are derived from prospectively phenotyped cases was a high priority. Proposed scales for grading DILI severity and assessing the likelihood of an agent causing DILI and written criteria for improving the reliability, accuracy, and reproducibility of expert opinion were reviewed. Finally, the unique challenges of assessing causality in children, patients with underlying liver disease, and subjects taking herbal and dietary supplements were discussed.

CONCLUSION

Workshop participants concluded that multicenter referral networks enrolling patients with suspected DILI according to standardized methodologies are needed. These networks should also collect biological samples that may provide crucial insights into the mechanism(s) of DILI with the ultimate aim of preventing future cases of DILI.

Phenotypic characterization of idiosyncratic drug-induced liver injury: the influence of age and sex

Increased age and female sex are suggested risk factors for drug-induced hepatotoxicity (DILI). We studied the influence of these variables on the propensity to develop DILI, as well as its clinical expression and outcome. All cases of DILI submitted to the Spanish Registry between April 1994 and August 2007 were analyzed. Six hundred three DILI cases (310 men; mean age, 54 years) showed a similar sex distribution, reaching two peaks in the 40- to 49-year-old and 60- to 69-year-old age groups. No cases were recorded in the 20- to 29-year-old group. Patients aged > or =60 years accounted for 46% of the cases, with a male predominance (158 males, 118 females; P= 0.009), as opposed to younger patients. Older age was independently associated with cholestatic type of injury (odds ratio for an age interval for 1 year: 1.024 [95% confidence interval: 1.010-1.038]; male/female ratio, 1:2; P = 0.001) and younger age with hepatocellular damage (odds ratio: 0.983 [95% confidence interval: 0.972-0.994]; female/male ratio, 1:2; P = 0.002). In the mixed group, no age effect was evident. Outcome with fulminant liver failure/liver transplantation was more frequently encountered in women (P < 0.01). conclusion: Neither older age nor female sex are predisposing factors to overall DILI. However, older age is a determinant for cholestatic damage with a male predominance, whereas younger age is associated with cytolytic damage and a female overrepresentation. Women distinctly exhibit the worst outcome. Knowledge of these phenotypic associations could guide differential diagnosis and attribution of causality in DILI.

HIV coinfection shortens the survival of patients with hepatitis C virus-related decompensated cirrhosis

The impact of human immunodeficiency virus (HIV) coinfection on the survival of patients with hepatitis C virus (HCV)-related end-stage liver disease (ESLD) is unknown. Because HIV infection is no longer considered an absolute contraindication for liver transplantation in some countries, it has become a priority to address this topic. The objective of this study was to compare the survival of HIV-infected and HIV-uninfected patients with decompensated cirrhosis due to HCV. In a retrospective cohort study, the survival of 1,037 HCV monoinfected and 180 HCV/HIV-coinfected patients with cirrhosis after the first hepatic decompensation was analyzed. Of the group, 386 (37%) HCV-monoinfected and 100 (56%) HCV/HIV-coinfected subjects died during the follow-up. The median survival time of HIV-infected and HIV-uninfected patients was 16 and 48 months, respectively (P < .001). The relative risk (95% CI) of death for HIV-infected patients was 2.26 (1.51-3.38). Other independent predictors of survival were age older than 63 years (2.25 [1.53-3.31]); Child-Turcotte-Pugh class B versus class A (1.95 [1.41-2.68]) and class C versus class A (2.78 [1.66-4.70]); hepatitis D virus infection (1.56 [1.12-4.77]); model for end-stage liver disease score, (1.05 [1.01-1-11]); more than one simultaneous decompensation (1.23 [1.12-3.33]); and the type of the first hepatic decompensation, with a poorer prognosis associated with encephalopathy compared with portal hypertensive gastrointestinal bleeding (2.03 [1.26-3.10]). In conclusion, HIV coinfection reduces considerably the survival of patients with HCV-related ESLD independently of other markers of poor prognosis. This fact must be taken into account to establish the adequate timing of liver transplantation in HIV-coinfected subjects.

Outcome of acute idiosyncratic drug-induced liver injury: Long-term follow-up in a hepatotoxicity registry

A chronic adverse reaction may occur in some instances of drug-induced liver injury (DILI), even despite drug cessation. In our study, we obtained records from a Spanish registry and evaluated cases of DILI with biochemical evidence of long-term damage. Chronic outcome was defined as a persistent biochemical abnormality of hepatocellular pattern of damage more than 3 months after drug withdrawal or more than 6 months after cholestatic/mixed damage. Data on 28 patients with a chronic clinical evolution (mean follow-up 20 months) between November 1995 and October 2005 were retrieved (18 female; overall mean age 55 yr) and accounted for 5.7% of total idiosyncratic DILI cases (n = 493) submitted to the registry. The main drug classes were cardiovascular and central nervous system (28.5% and 25%, respectively), which, in contrast, represented only 9.8% and 13%, respectively, of all DILI cases. The most frequent causative drugs were amoxicillin-clavulanate (4 of 69 cases), bentazepam (3 of 7 cases), atorvastatin (2 of 7 cases), and captopril (2 of 5 cases). Patients with cholestatic/mixed injury (18 of 194 cases [9%]) were more prone to chronicity than patients with hepatocellular injury (10 of 240 cases; P < .031). In the case of chronic hepatocellular injury, 3 patients progressed to cirrhosis and 2 to chronic hepatitis. In the cholestatic/mixed group, liver biopsy indicated cirrhosis in 1 patient and ductal lesions in 3 patients. In conclusion, cholestatic/mixed type of damage is more prone to become chronic while, in the hepatocellular pattern, the severity is greater. Cardiovascular and central nervous system drugs are the main groups leading to chronic liver damage.

Obesity-dependent metabolic signatures associated with nonalcoholic fatty liver disease progression

Our understanding of the mechanisms by which nonalcoholic fatty liver disease (NAFLD) progresses from simple steatosis to steatohepatitis (NASH) is still very limited. Despite the growing number of studies linking the disease with altered serum metabolite levels, an obstacle to the development of metabolome-based NAFLD predictors has been the lack of large cohort data from biopsy-proven patients matched for key metabolic features such as obesity. We studied 467 biopsied individuals with normal liver histology (n=90) or diagnosed with NAFLD (steatosis, n=246; NASH, n=131), randomly divided into estimation (80% of all patients) and validation (20% of all patients) groups. Qualitative determinations of 540 serum metabolite variables were performed using ultraperformance liquid chromatography coupled to mass spectrometry (UPLC-MS). The metabolic profile was dependent on patient body-mass index (BMI), suggesting that the NAFLD pathogenesis mechanism may be quite different depending on an individual's level of obesity. A BMI-stratified multivariate model based on the NAFLD serum metabolic profile was used to separate patients with and without NASH. The area under the receiver operating characteristic curve was 0.87 in the estimation and 0.85 in the validation group. The cutoff (0.54) corresponding to maximum average diagnostic accuracy (0.82) predicted NASH with a sensitivity of 0.71 and a specificity of 0.92 (negative/positive predictive values=0.82/0.84). The present data, indicating that a BMI-dependent serum metabolic profile may be able to reliably distinguish NASH from steatosis patients, have significant implications for the development of NASH biomarkers and potential novel targets for therapeutic intervention.

Comparison of two clinical scales for causality assessment in hepatotoxicity

This study was performed to compare the assessments of drug-induced liver injury obtained with 2 methods, the Council for International Organizations of Medical Sciences (CIOMS) scale and the recently validated Maria & Victorino (M&V) clinical scale, in cases submitted to a registry of hepatotoxicity. A total of 215 cases of hepatotoxicity reported with a structured reporting form were evaluated by 3 independent experts. Because of the use of multiple drugs, 228 ratings were generated. The probability of the diagnosis was classified as definitive, probable, possible, unlikely, or excluded, and evaluated for consistency with a weighted kappa statistical test. Absolute agreement between the 2 scales was observed in 42 cases (18%, weighted kappa 0.28) with disagreement of 1 level in 108 cases (47%), and of 2 levels in 70 cases (31%). The best correlation between the 2 scales was obtained for drug-induced liver injury involving a suggested immunoallergic mechanism: the disagreement was 1 level or less in 72% of the cases (34 of 48), compared with 60% of the cases (85 of 141) that involved a presumed idiosyncratic metabolic mechanism. The lowest agreement (6%) was observed in cases with evidence of cholestasis. No agreement was found in cases of fulminant hepatitis or death. The CIOMS scale showed better discriminative power and produced assessments closer to those of specialists. The performance of the M&V scale was poor in reactions with long latency periods (i.e., amoxycillin/clavulanic acid), evolution to chronicity after withdrawal (cholestatic pattern), or death.

Effect of sustained virological response to treatment on the incidence of abnormal glucose values in chronic hepatitis C

BACKGROUND/AIMS

To investigate the effect of sustained virological response (SVR) on impaired fasting glucose (IFG) and/or type 2 diabetes (T2DM); to assess the influence of glucose abnormalities on the SVR rate.

METHODS

1059 patients with chronic HCV; normal glucose (< 100 mg/dl) in 734, IFG (between 100 and 125 mg/dl) in 218, and T2DM (126 mg/dl) in 107 cases, were treated with interferon plus ribavirin over 24 or 48 weeks, depending on viral genotype.

RESULTS

The SVR rate was lower in patients with IFG and/or T2DM than in patients with normal glucose concentrations [143/325 (44%) vs. 432/734 (58.8%); P=0.002]. In the follow-up, abnormal glucose concentrations were observed in 74 of 304 (24.3%) non-responders and in 49 of 430 (11.4%) sustained responders (log-rank: 13.8; P=0.00002). Reverse stepwise logistic regression analysis identified the independent variables predictive of IFG or T2DM development as: sustained response (OR: 0.44; 95%CI=0.20-0.97; P=0.004) and fibrosis stage (OR: 1.46; 95%CI=1.06-2.01;P=0.02). Family history of DM, steatosis, gender, HCV viral load, genotype, triglycerides, cholesterol and BMI did not enter the multivariate analysis equation.

CONCLUSIONS

SVR reduces the risk of IFG and/or T2DM development in patients with chronic hepatitis C while altered glucose metabolism impairs sustained response to viral treatment.

Glutathione S-transferase m1 and t1 null genotypes increase susceptibility to idiosyncratic drug-induced liver injury

Individual vulnerability to drug-induced liver injury (DILI) might result from deficiencies in the detoxification process, which determines the level of exposure to the reactive metabolite. We evaluated whether a genetically determined reduction in the ability to detoxify electrophilic compounds, such as that expected among individuals with glutathione S-transferase (GST) null genotypes, might play a role in determining the risk for DILI and its clinical expression. Genomic DNA from 154 patients (74 men, 80 women; mean age, 53 years) with a diagnosis of DILI as assessed with the Council for International Organizations of Medical Science scale and 250 sex- and age-matched healthy controls were analyzed. A multiplex polymerase chain reaction-based method was used to detect GSTM1 and GSTT1 gene deletions. Carriers of double GSTT1-M1 null genotypes had a 2.70-fold increased risk of developing DILI compared with noncarriers (odds ratio 2.70, 95% confidence interval 1.45-5.03; P = 0.003). The odds ratio for DILI patients receiving antibacterials, and NSAIDs were 3.52 (P = 0.002), and 5.61 (P = 0.001), respectively. Patients with amoxicillin-clavulanate hepatotoxicity (n = 32) had a 2.81-fold increased risk (P = 0.037). Patients classified by the combined GSTT1 and GSTM1 null genotypes did not differ with regard to the type of injury, clinical presentation, or outcome, except for the predominance of women in the combined null genotype (P < 0.001).

CONCLUSION

The double-null genotype for GSTT1 and GSTM1 might play a role in determining the susceptibility to develop DILI, as a general mechanism that occurs regardless of the type of drug involved, and predominantly in women.

Evaluation of naranjo adverse drug reactions probability scale in causality assessment of drug-induced liver injury

BACKGROUND

Causality assessment in hepatotoxicity is challenging. The current standard liver-specific Council for International Organizations of Medical Sciences/Roussel Uclaf Causality Assessment Method scale is complex and difficult to implement in daily practice. The Naranjo Adverse Drug Reactions Probability Scale is a simple and widely used nonspecific scale, which has not been specifically evaluated in drug-induced liver injury.

AIM

To compare the Naranjo method with the standard liver-specific Council for International Organizations of Medical Sciences/Roussel Uclaf Causality Assessment Method scale in evaluating the accuracy and reproducibility of Naranjo Adverse Drug Reactions Probability Scale in the diagnosis of hepatotoxicity.

METHODS

Two hundred and twenty-five cases of suspected hepatotoxicity submitted to a national registry were evaluated by two independent observers and assessed for between-observer and between-scale differences using percentages of agreement and the weighted kappa (kappa(w)) test.

RESULTS

A total of 249 ratings were generated. Between-observer agreement was 45% with a kappa(w) value of 0.17 for the Naranjo Adverse Drug Reactions Probability Scale, while there was a higher agreement when using the Council for International Organizations of Medical Sciences/Roussel Uclaf Causality Assessment Method scale (72%, kappa(w): 0.71). Concordance between the two scales was 24% (kappa(w): 0.15). The Naranjo Adverse Drug Reactions Probability Scale had low sensitivity (54%) and poor negative predictive value (29%) and showed a limited capability to distinguish between adjacent categories of probability.

CONCLUSION

The Naranjo scale lacks validity and reproducibility in the attribution of causality in hepatotoxicity.

Hepatic safety of antibiotics used in primary care

Antibiotics used by general practitioners frequently appear in adverse-event reports of drug-induced hepatotoxicity. Most cases are idiosyncratic (the adverse reaction cannot be predicted from the drug's pharmacological profile or from pre-clinical toxicology tests) and occur via an immunological reaction or in response to the presence of hepatotoxic metabolites. With the exception of trovafloxacin and telithromycin (now severely restricted), hepatotoxicity crude incidence remains globally low but variable. Thus, amoxicillin/clavulanate and co-trimoxazole, as well as flucloxacillin, cause hepatotoxic reactions at rates that make them visible in general practice (cases are often isolated, may have a delayed onset, sometimes appear only after cessation of therapy and can produce an array of hepatic lesions that mirror hepatobiliary disease, making causality often difficult to establish). Conversely, hepatotoxic reactions related to macrolides, tetracyclines and fluoroquinolones (in that order, from high to low) are much rarer, and are identifiable only through large-scale studies or worldwide pharmacovigilance reporting. For antibiotics specifically used for tuberculosis, adverse effects range from asymptomatic increases in liver enzymes to acute hepatitis and fulminant hepatic failure. Yet, it is difficult to single out individual drugs, as treatment always entails associations. Patients at risk are mainly those with previous experience of hepatotoxic reaction to antibiotics, the aged or those with impaired hepatic function in the absence of close monitoring, making it important to carefully balance potential risks with expected benefits in primary care. Pharmacogenetic testing using the new genome-wide association studies approach holds promise for better understanding the mechanism(s) underlying hepatotoxicity.

Treatment of insulin resistance with metformin in naïve genotype 1 chronic hepatitis C patients receiving peginterferon alfa-2a plus ribavirin

Insulin resistance affects sustained virological response (SVR) in chronic hepatitis C. To know whether adding metformin to standard antiviral treatment improves SVR, we conducted a prospective, multicentered, randomized, double-blinded, placebo-controlled trial in 19 Spanish hospitals, including 123 consecutive patients with genotype 1 chronic hepatitis C and insulin resistance. Patients were randomized to receive either metformin (arm A; n = 59) or placebo (arm B; n = 64) in addition to peginterferon alfa-2a (180 microg/week) and ribavirin (1000-1200 mg/day). The primary end point was SVR, and secondary endpoints were viral clearance at weeks 12, 24, and 48, and changes in the homeostasis model assessment (HOMA) index over the first 24 weeks. There were no differences between arms at baseline. In the intent-to-treat analysis, SVR was observed in 53% versus 42% in arm A and arm B, respectively (P = NS). In the subgroup analyses, SVR was higher in females (n = 54) receiving metformin: arm A, 58% (15/26) versus 29% (8/28) arm B (P = 0.03). In the per protocol analysis (PPA; n = 101), SVR was 67% in arm A and 49% in arm B (P = 0.06). Viral decline during the first 12 weeks was greater in females receiving metformin: -4.88 (1.18) versus -4.0 (1.44) (P = 0.021), whereas no differences were seen in males. The triple therapy was well tolerated, but diarrhea was more often seen in arm A (34% versus 11%; P < 0.05).

CONCLUSION

Adding metformin to peginterferon and ribavirin was safe and improved insulin sensitivity. Although the study failed to show a statistically significant difference between arms, it did show an improved SVR in females.

Diverse BF recombinants have spread widely since the introduction of HIV-1 into South America

OBJECTIVE

To describe the genetic diversity of HIV-1 in South America by full genome sequencing and analysis.

METHODS

Purified peripheral blood mononuclear cell DNA from HIV-infected individuals in Argentina, Uruguay and Bolivia was used to amplify full HIV-1 genomes. These were sequenced using the ABI 3100 automated sequencer and phylogenetically analysed.

RESULTS

Twenty-one HIV-1 strains from three South American countries, 17 of which were pre-screened by envelope heteroduplex mobility assay (HMA), were studied. Ten out of 10 HMA subtype F and four out of seven HMA subtype B strains were actually BF recombinants upon full genome analysis. Two BF recombinants from Argentina and two from Uruguay had the same structure, representing a new circulating recombinant form termed CRF12_BF(ARMA159). Twelve other BF recombinants had structures related to CRF12 but with additional segments of subtype B; each was unique. BF recombinants were temporally and geographically widespread, found as early as 1986-1987 in vertically infected Argentinian children and in Argentina, Uruguay, and Bolivia.

Can chronic stretching change the muscle-tendon mechanical properties? A review

It is recognized that stretching is an effective method to chronically increase the joint range of motion. However, the effects of stretching training on the muscle-tendon structural properties remain unclear. This systematic review with meta-analysis aimed to determine whether chronic stretching alter the muscle-tendon structural properties. Published papers regarding longitudinal stretching (static, dynamic and/or PNF) intervention (either randomized or not) in humans of any age and health status, with more than 2 weeks in duration and at least 2 sessions per week, were searched in PubMed, PEDro, ScienceDirect and ResearchGate databases. Structural or mechanical variables from joint (maximal tolerated passive torque or resistance to stretch) or muscle-tendon unit (muscle architecture, stiffness, extensibility, shear modulus, volume, thickness, cross-sectional area, and slack length) were extracted from those papers. A total of 26 studies were selected, with a duration ranging from 3 to 8 weeks, and an average total time under stretching of 1165 seconds per week. Small effects were seen for maximal tolerated passive torque, but trivial effects were seen for joint resistance to stretch, muscle architecture, muscle stiffness, and tendon stiffness. A large heterogeneity was seen for most of the variables. Stretching interventions with 3- to 8-week duration do not seem to change either the muscle or the tendon properties, although it increases the extensibility and tolerance to a greater tensile force. Adaptations to chronic stretching protocols shorter than 8 weeks seem to mostly occur at a sensory level.