YMDD variants of HBV DNA polymerase gene: Rapid detection and clinicopathological analysis with long-term lamivudine therapy after liver transplantation

The relationship between gastroesophageal reflux disease and chronic periodontitis

Background/Aims

The most common cause of chronic periodontitis is poor oral hygiene. Gastroesophageal reflux disease (GERD) enhances the proximal migration of gastric contents and may cause poor oral hygiene. We hypothesized that GERD may increase thse risk of chronic periodontitis and investigated this potential relationship.

Methods

A retrospective cross-sectional study was conducted in outpatients between January 1, 2010, and April 30, 2012. GERD was defined as being present based on at least two of the following criteria: etiologic agent(s), identifiable signs and symptoms, and consistent anatomic alterations. A total of 280 patients with chronic periodontitis and 280 controls were analyzed. Information regarding patient demographics and other potential confounding factors for chronic periodontitis were collected through individual medical records.

Results

GERD was revealed to be independently associated with an increased incidence of chronic periodontitis (odds ratio [OR], 2.883; 95% confidence interval [CI], 1.775 to 4.682). The other three variables of dental caries (OR, 1.531; 95% CI, 1.042 to 2.249), tobacco use (OR, 2.335; 95% CI, 1.461 to 3.730), and history of medication (calcium channel blocker, cyclosporine, or phenytoin) (OR, 2.114; 95% CI, 1.160 to 3.854) were also determined to be independent risk factors.

Conclusions

The present study supported our hypothesis that GERD can be a risk factor for chronic periodontitis.

Frequency and mutation patterns of resistance in patients with chronic hepatitis B infection treated with nucleos(t)ide analogs in add-on and switch strategies

BACKGROUND

Treatment for chronic hepatitis B (CHB) has improved over the last 10 years mainly due to the development of effective oral antiviral agents [nucleoside/nucleotide analogs (NUCs)].

OBJECTIVES

The aim of the present study is to identify the frequency and major patterns of resistance to the hepatitis B virus (HBV) in a Turkish population of CHB patients treated with NUCs using add-on and switch therapy strategies.

PATIENTS AND METHODS

The investigation involved a total of 194 patients (88 were treated using add-on therapy, and 106 were treated using switch therapy). We analyzed the HBV polymerase gene by amplification and direct sequencing procedures.

RESULTS

Primary drug-resistance mutations were detected in 84 patients (43%; 42 in add-on therapy, and 42 in switch therapy) taking lamivudine (LAM), 10 patients (5%; 6 in add-on therapy, and 4 in switch therapy) taking entecavir (ETV), and 16 patients (8%; 8 in add-on therapy, and 8 in switch therapy) taking adefovir (ADV). The most common LAM and ETV resistance mutations were rtM204I/V, rtL180M and rtT184A/I/S, respectively, while rtA181T/V and rtN236T substitutions were the most frequently observed ADV resistance mutations.

CONCLUSIONS

Patients with CHB who developed NUC resistance were managed using 2 different rescue strategies. The frequency and mutation pattern of resistance were similar in patients treated with add-on and switch strategies. These findings may be helpful in the management of rescue strategies in LAM-resistant patients.

An early decrease in serum HBeAg titre is a strong predictor of virological response to entecavir in HBeAg-positive patients

Quantification of HBeAg levels has been found to be useful in monitoring and predicting the outcomes of interferon and lamivudine treatment in HBeAg-positive patients. The aim of this study was to determine whether quantification of HBeAg at baseline and on treatment could predict which patients would achieve HBeAg seroconversion after 96 weeks of entecavir therapy. Sixty-five HBeAg-positive naïve chronic hepatitis B patients who were treated with entecavir at a dose of 0.5 mg once daily for 96 weeks were evaluated. Serum HBV DNA levels were assessed at baseline, week 24, 48 and 96; serum HBeAg levels were assessed at baseline, week 12, 24, 48, 72 and 96. Serum HBeAg levels were associated with a higher likelihood of HBeAg seroconversion to entecavir at weeks 96 than serum HBV DNA levels both at baseline and on treatment (at baseline: OR = 9.932, P = 0.003 vs. OR = 5.045, P = 0.036; on treatment: OR = 112.5, P < 0.0001 vs. OR = 47.782, P < 0.0001). A maintained reduction in HBeAg > 65% of pretreatment HBeAg values after 24 weeks of entecavir therapy is the strongest predictor for HBeAg seroconversion at week 96 (OR = 70.578, P < 0.0001). Quantification of HBeAg at the start and early during therapy showed a higher predictive value than that of HBV DNA for HBeAg seroconversion by entecavir. A significant decrease in serum HBeAg levels at week 24 may be a useful on-treatment measurement in the early phase for predicting HBeAg seroconversion and identifying patients who will most likely benefit from finite entecavir treatment.

Probing rate of YMDD motif mutant in lamivudine treatment of Iranian patients with chronic hepatitis B virus infection

Background:

Lamivudine is an analog nucleoside used for the treatment of chronic hepatitis B virus (CHV) infection. Studies showed that prolonged therapy could induce lamivudine resistance hepatitis B virus (HBV) variants (YMDD motif). In this study, the rate of YMDD motif mutants is determined in lamivudine-treated CHV patients in Iran.

Materials and Methods:

Thirty-three serum specimens of patients with chronic hepatitis who had been treated with lamivudine were included in the study. Serum samples of patients were tested by PCR flash and RFLP as well as tested for HBeAg, HBsAg, and liver enzymes (ALT and AST).

Results:

Out of the 33 patients enrolled in this study, 82% were male and 18% female, respectively. Mean ALT levels were between 20 and 100 IU/1. HBeAg was positive in 76% of the patients whereas HBs was positive only in 61% of the patients. Furthermore, in 28 patients liver biopsy grade was between 2 and 17 having the stage of 1–6. Moreover, HBsAg negative and HBeAg positive were observed in 30% of the patients.

Conclusion:

During therapy, it was found that patients with lamivudine incidence YMDD mutation were approximately 14%. The ALT levels were also reduced in these patients. This study revealed that there was a significant difference between HBeAg, grade, and YMDD mutation whereas no significant different was observed between HBsAg and HBV DNA PCR. Conclusively, it was found that a significant difference exists between YMDD mutation and lamivudine therapy (17% of patients were HBsAg negative and PCR positive).

Rapid detection of the hepatitis B virus YMDD mutant using AllGlo™ probes

BACKGROUND

The early detection of hepatitis B virus (HBV) mutants in clinical samples is important when monitoring chronic HBV patients with lamivudine-resistant mutations during lamivudine therapy.

METHODS

The AllGlo™ probes were designed to distinguish between wild-type (YMDD) and mutant (YVDD and YIDD) strains of HBV. The sensitivity and specificity of the assay were evaluated using a series of diluted mixtures of wild-type and mutant plasmids. This assay was compared with direct sequencing and the mutation-specific primer assay.

RESULTS

Each YMDD, YVDD, and YIDD probe only detected its corresponding plasmid. Moreover, the assay correctly identified negative samples from 40 non-HBV infected patients and 100 healthy controls. The detection limit of this assay was 50 copies/ml for YVDD and YIDD. The assay could detect the mutant strains when they were present at ≥10% within a mixed virus population. The assay was fully concordant with direct sequencing in 34 samples (56.7%) and partially concordant in 26 samples (43.3%), and detected more types of the HBV motif than direct sequencing.

CONCLUSIONS

AllGlo™ probe assay is a novel, sensitive and specific assay to detect lamivudine-related HBV mutants, therefore, may be useful for monitoring chronic HBV patients treated with lamivudine.

Molecular diagnosis of entecavir resistance

Entecavir (ETV) is a potent nucleoside analogue against hepatitis B virus (HBV). Because of development of ETV resistance requires at least three amino acid substitutions in HBV polymerase (pol) gene, emergence of ETV resistance is rare (~1%) in nucleoside-naive patients after up to 5 years of treatment. However, it has been suggested that lamivudine (LAM) therapy can preselect for HBV variants associated with resistance to ETV treatment. ETV resistance increased to 51% of patients after 5 years of ETV treatment in LAM refractory patients. The diagnosis of ETV resistance in chronic hepatitis B patients, mainly based on four types of molecular assays: direct sequencing, line probe assay, clonal analysis,and restriction fragment length polymorphism (RFLP) analysis. The applications of other assays are currently more specialized,and their use is more limited. The utility of these assays and their performance characteristics are reviewed below.Briefly, the monitoring of drug-resistant variants is important in the elucidation of the prevalence and mechanisms of resistance development and for the more effective management of treatment options.

Naturally occurring amino-acid substitutions to nucleos(t)ide analogues in treatment naive Turkish patients with chronic hepatitis B

Naturally occurring amino-acid substitutions in the hepatitis B virus (HBV) polymerase gene may be responsible for resistance to nucleoside/nucleotide (NUCs) analogues. To date, only pre-existing lamivudine resistance has been extensively studied. The aim of the present study was to determine the naturally occurring or pre-existing amino-acid substitutions related to NUCs in treatment naive Turkish patients with chronic hepatitis B (CHB). The investigation involved a total of 88 patients (65 males and 23 females; mean age, 34 years; range, 15-61 years) who were diagnosed with CHB between April 2008 and January 2009. According to HBeAg status, 66 patients were HBeAg-negative and 22 patients were HBeAg positive. Naturally occurring substitutions in the HBV polymerase region were detected by DNA sequencing in 17 (19%) and 30 (34%) patients, based on manual and geno2pheno tool database interpretation, respectively. Each amino-acid substitution appeared alone and included rtA194T, rtV214A, rtQ215S, rtI233V and rtN236T. The median values for viral load, ALT and AST were 3.3 log(10) (2.0-6.0) IU/mL, 36 (12-515) U/L and 27 (13-284) U/L, respectively, but these did not correlate with the observed amino-acid substitutions in the polymerase region. By direct sequencing, genotype D of HBV was found to still be dominant among Turkish patients. In conclusion, every patient who is diagnosed with CHB should be monitored before the start of treatment for more effective management of patient treatment options.

Gastroesophageal reflux disease (GERD): is there more to the story?

Gastroesophageal reflux disease (GERD) affects both men and women worldwide, with the most common symptom of GERD being frequent heartburn. If left untreated, more serious diseases including esophagitis and/or esophageal cancer may result. GERD has been commonly held to be the result of gastric acid refluxing into the esophagus. Recent work, however, has shown that there are acid-producing cells in the upper aerodigestive tract. In addition, acid-producing bacteria located within the upper gastrointestinal tract and oral cavity may also be a contributing factor in the onset of GERD. Proton pump inhibitors (PPIs) are commonly prescribed for treating GERD; these drugs are designed to stop the production of gastric acid by shutting down the H(+)/K(+)-ATPase enzyme located in parietal cells. PPI treatment is systemic and therefore significantly different than traditional antacids. Although a popular treatment choice, PPIs exhibit substantial interpatient variability and commonly fail to provide a complete cure to the disease. Recent studies have shown that H(+)/K(+)-ATPases are expressed in tissues outside the stomach, and the effects of PPIs in these nongastric tissues have not been fully explored. Likewise, acid-producing bacteria containing proton pumps are present in both the oral cavity and esophagus, and PPI use may also adversely affect these bacteria. The use of PPI therapy is further complicated by the two philosophical approaches to treating this disease: to treat only symptoms or to treat continuously. The latter approach frequently results in unwanted side effects which may be due to the PPIs acting on nongastric tissues or the microbes which colonize the upper aerodigestive tract.

A novel accurate ACRS-PCR method with a digestion internal control for identification of wild type and YMDD mutants of hepatitis B virus strains

As a consequence of the point mutation in the YMDD motif of the hepatitis B virus (HBV) polymerase gene, lamivudine-resistant mutants have been reported in chronic hepatitis B patients who underwent lamivudine therapy. The objective of the study was to develop a novel accurate artificially created restriction site (ACRS) method with a digestion internal control for identification of YMDD, YIDD and YVDD HBV strains. Three conserved, specific and diagnostic primers introducing NdeI, SspI and AleI cleavage sites were designed in order to identify YMDD, YIDD and YVDD strains, respectively; while, their reverse primers also modified with the above recognition sites in order to enzyme correctness monitoring and false outcome avoiding. Thirty-two chronic hepatitis B patients who had taken lamivudine for 1-3 years and checked by the Inno-LiPA HBV DR kit, were evaluated by the ACRS method and then compared to sequencing data. The results of the ACRS method revealed the YMDD mutant strain in 20 patients, YMDD plus YIDD pattern in 1 patient, YMDD plus YVDD in 4 patients, the YIDD in 4 patients and mixed infection with each three strains in 1 patient. The sequencing and Inno-LiPA results were in agreement with the ACRS results. The novel ACRS method is a reliable, rapid and a cost-effective technique for determination of HBV strains with the wild type and YMDD mutant patterns.