Helicobacter pylori infection, serum pepsinogens as markers of atrophic gastritis, and leukocyte telomere length: a population-based study.

BACKGROUND: Persistent infections that induce prolonged inflammation might negatively affect the leukocyte telomere length (LTL); however, the role in LTL of Helicobacter pylori (H. pylori) infection, which persistently colonizes the stomach, remains unknown. The study objective was to examine associations of sero-prevalence of H. pylori immunoglobulin G (IgG) antibody and serum pepsinogens (PGs), as markers of atrophic gastritis, with LTL. A cross-sectional study was performed among 934 Arab residents of East Jerusalem, aged 27-78 years, randomly selected from Israel's national population registry. Sera were tested for H. pylori IgG and PG levels by ELISA. LTL was measured by southern blots. Multiple linear regression models were fitted to adjust for sociodemographic and lifestyle factors. RESULTS: LTL decreased significantly with age (p < 0.001) and was shorter in men than women (p = 0.032). The mean LTL was longer in H. pylori sero-positive persons than negative ones: mean difference 0.13 kb (95% CI 0.02, 0.24), p = 0.016. Participants with atrophic gastritis (PGI < 30 µg/L or a PGI: PGII < 3.0) had shorter LTL than did those without: mean difference - 0.18 (95% CI - 0.32, - 0.04). The difference was of larger magnitude between persons who had past H. pylori infection (sero-negative to H. pylori IgG antibody) and atrophic gastritis, compared to those who were H. pylori sero-negative and did not have atrophic gastritis: mean difference - 0.32 kb (95% CI - 0.55, - 0.10). This association remained significant after adjustment for age, sex, and religiosity: beta coefficient - 0.21 kb (95% CI - 0.41, - 0.001), p = 0.049. The results were similar after further adjustment for lifestyle factors. In bivariate analysis, mean LTL was longer in physically active persons than non-active ones, and shorter in persons with than without obesity; however, these differences were diminished and were not significant in the multivariable model. CONCLUSIONS: H. pylori IgG sero-positivity per se was not related to reduced LTL. However, persons with past H. pylori infection (i.e., lacking H. pylori IgG serum antibody) and with serological evidence of atrophic gastritis, had a significantly shorter LTL than did those without atrophic gastritis.

Helicobacter pylori eradication increases telomere length in gastric mucosa.

BACKGROUND/AIMS: Our purpose in this study was to analyze telomere length and telomerase activity before and after eradication treatment in gastric mucosa in patients positive for H. pylori. METHODOLOGY: There were two groups: a control group (n=17) and a study group (n=21). For H. pylori eradication, the patients were administrated proton pump inhibitor (PPI) + clarithromycin + amoxicillin or PPI + metronidazole + tetracycline + bismuth for 14 days. Telomere length was analyzed with RT-PCR and telomerase activity with PCR-ELISA on biopsy specimens from the antrum. The result p<0.05 was considered significant. RESULTS: Prior to eradication, there was no significant difference between telomere lengths of the patient and control groups (2481.2±1823 and 2958.9±1345.7 bp, p=0.11, respectively). The telomere length of the study group became longer after eradication (before 2481.2±1823bp, after 3766.3±1608.8bp, p=0.01). Telomerase activity was not detected in either the patient or the control group. CONCLUSIONS: An increase in telomere length was observed with H. pylori eradication. This finding may indicate the importance of H. pylori eradication to avoid the development of gastric cancer.

Characterization of Kluyveromyces lactis subtelomeric sequences including a distal element with strong purine/pyrimidine strand bias.

Telomeres are the specialized structures at the ends of eukaryotic chromosomes and are composed of short T/G-rich DNA repeats and the proteins that interact with them. Internal to telomeres are subtelomeric regions that are species-specific and often repetitive. The yeast Kluyveromyces lactis has telomeric tracts of 10-20 copies of a 25 bp repeat, but the subtelomeric regions have not previously been characterized in detail. Here we have cloned and characterized subtelomeric regions from 10 of the 12 chromosome ends. The amount of sequence examined was 0.7-10 kb for each subtelomeric region. We have identified a K. lactis subtelomeric element, the R element, which has a strong purine/pyrimidine strand bias and extends for about 2 kb. Internal to the R element, we found extensive similarity that is shared among half of the chromosome ends reported here. This similarity appears to include three putative gene families, two of which are also subtelomeric in Saccharomyces cerevisiae.