Aino Oksanen

Transcriptional regulation of the lactase-phlorizin hydrolase gene by polymorphisms associated with adult-type hypolactasia

Background and aims: The mechanism of the developmental downregulation of the lactase-phlorizin hydrolase (LPH) gene underlying adult-type hypolactasia is unknown. We have determined the functional significance of the recently identified two single nucleotide polymorphisms (SNPs), C/T−13910 and G/A−22018, associated with adult-type hypolactasia by studying LPH mRNA levels in intestinal biopsy samples with different genotypes. Methods: Intestinal biopsy samples were taken from 52 patients with abdominal complaints. Hypolactasia was diagnosed by determining lactase and sucrase activities and calculating their ratio (L/S ratio). The functional effect of the C/T−13910 and G/A−22018 genotype on expression of LPH mRNA was demonstrated in patients heterozygous for the C/T−13910 and G/A−22018 polymorphism and an informative expressed SNP located in the coding region of the LPH mRNA. Reverse transcription-polymerase chain reaction followed by solid phase minisequencing was used for accessing the relative expression levels of the LPH alleles using informative SNPs located in exons 1, 2, 6, 10, 13, or 17 as markers. Results: Statistically significant differences between the three different genotypes CC−13910 GG−22018, CT−13910 GA−22018, and TT−13910 AA-22018 and their respective L/S ratios were observed. Relative quantitation of the expressed LPH alleles showed that the persistent allele represented 92 (6)% (mean (SEM), range 78–99%; n=14) of the expressed LPH mRNA. The patient with the homozygous persistent TT−13910 AA−22018, as well as hypolactasic patients with CC−13910 GG−22018, showed equal expression of both alleles (47 (1)%; n=7). Conclusions: Expression of LPH mRNA in the intestinal mucosa in individuals with T−13910 A−22018 alleles is several times higher than that found in individuals with C−13910, G−22018 alleles. These findings suggest that the two SNPs, C/T−13910 and G/A−22018, associated with adult-type hypolactasia, are associated with the transcriptional regulation of the LPH gene. The presence of the T−13910 A−22018 allele also shows significant elevation of the L/S ratio.

Enhanced systemic matrix metalloproteinase response in Helicobacter pylori gastritis.

Background. Helicobacter pylori causes chronic gastritis, peptic ulcer disease, and is the most important risk factor for non-cardia gastric cancer, and has been shown to upregulate matrix metalloproteinases (MMPs) in infected gastric mucosa. MMPs are proteolytic enzymes regulated by tissue inhibitors of metalloproteinases (TIMPs). Aims. We set up this study to find out whether H. pylori gastritis induces systemic MMP response. Methods. Serum samples were collected from patients undergoing gastroscopy; 26 patients had H. pylori gastritis and 18 were H. pylori-negative controls with normal gastric mucosa. Serum MMP levels were analysed by enzyme-linked immunosorbent assay. Results. Significantly elevated serum levels of collagenase-2 (MMP-8), gelatinase B (MMP-9), neutrophil elastase (NE), and myeloperoxidase (MPO), and reduced serum levels of gelatinase A (MMP-2) and TIMP-1 were demonstrated in patients with H. pylori gastritis as compared to H. pylori-negative controls. No significant differences were shown in serum matrilysin-1 (MMP-7) levels. Conclusions. For the first time, we show enhanced MMP-8 response in H. pylori infection together with other neutrophil degranulation products (MMP-9, MPO, NE). Elevated circulating neutrophil degranulation product levels in serum of H. pylori-positive patients reflect accelerated proteolysis and oxidative stress, and may contribute to extraintestinal sequelae, such as cardiovascular diseases.

Evaluation of Blood Tests to Predict Normal Gastric Mucosa

BACKGROUND To determine the accuracy of blood tests in predicting normal gastric mucosa confirmed by histological examination of gastric biopsy specimens. METHODS In total, 207 consecutive patients referred for upper endoscopy were included. Two biopsy specimens each from the antrum and corpus were assessed histologically for the presence of Helicobacter pylori, gastritis, and atrophy. Serum samples were studied for H. pylori antibodies by enzyme immunoassay (Pyloriset EIA-G and EIA-A) and by a rapid latex agglutination test (Pyloriset Dry); pepsinogen I was measured by an immunoenzymometric assay (Gastroset PGI), gastrin by radioimmunoassay, and parietal cell antibodies by indirect immunofluorescence. RESULTS In 101 (49%) of 207 patients, the gastric mucosa on histologic examination was normal. In the 63 patients aged 45 years or less, H. pylori IgG serology was negative in all 47 patients with normal gastric mucosa and none had low serum pepsinogen I levels. Among 144 patients over age 45 years, 72 had negative H. pylori IgG serology. Combining the serum pepsinogen I assay with the results of H. pylori IgG serology, 12 patients with normal serology but low serum pepsinogen I were found. Thus, 60 patients, 52 of whom showed normal gastric histology, had normal IgG serology and serum pepsinogen 1. In the remaining eight patients with normal blood tests, the histologic changes were very mild. CONCLUSIONS Although negative H. pylori IgG serology alone in younger patients, and in combination with normal serum pepsinogen I levels in older patients, reliably predicted the presence of normal gastric mucosa, gastroscopy is still recommended for patients over 45 years.Background: To determine the accuracy of blood tests in predicting normal gastric mucosa confirmed by histological examination of gastric biopsy specimens. Methods: In total, 207 consecutive patients referred for upper endoscopy were included. Two biopsy specimens each from the antrum and corpus were assessed histologically for the presence of Helicobacter pylori, gastritis, and atrophy. Serum samples were studied for H. pylori antibodies by enzyme immunoassay (Pyloriset EIA-G and EIA-A) and by a rapid latex agglutination test (Pyloriset Dry); pepsinogen I was measured by an immunoenzymometric assay (Gastroset PGI), gastrin by radioimmunoassay, and parietal cell antibodies by indirect immunofluorescence. Results: In 101 (49%) of 207 patients, the gastric mucosa on histologic examination was normal. In the 63 patients aged 45 years or less, H. pylori IgG serology was negative in all 47 patients with normal gastric mucosa and none had low serum pepsinogen I levels. Among 144 patients over age 45 years, 72 had negative H. pylori IgG serology. Combining the serum pepsinogen I assay with the results of H. pylori IgG serology, 12 patients with normal serology but low serum pepsinogen I were found. Thus, 60 patients, 52 of whom showed normal gastric histology, had normal IgG serology and serum pepsinogen I. In the remaining eight patients with normal blood tests, the histologic changes were very mild. Conclusions: Although negative H. pylori IgG serology alone in younger patients, and in combination with normal serum pepsinogen I levels in older patients, reliably predicted the presence of normal gastric mucosa, gastroscopy is still recommended for patients over 45 years.

Comparison of three stool antigen tests in confirming Helicobacter pylori eradication in adults

Objective Reliable and readily available non-invasive methods are needed for detection of Helicobacter pylori infection and assessment of eradication therapy. In H. pylori-positive subjects we compared three stool antigen tests (Premier Platinum HpSA, Amplified IDEIA HpStAR and ImmunoCard STAT!HpSA) with invasive tests before their eradication therapy, and with non-invasive diagnostic methods after their therapy. Material and methods A total of 82 adults with dyspepsia (aged 24–79 years) with an H. pylori-positive rapid urease test were enrolled in the study. Before therapy, H. pylori status was also confirmed with histology, culture and serology. After eradication, success was assessed with the [13C]-urea breath test (UBT) and usually also with serology. Results At baseline, sensitivities of these stool antigen tests were 90.2% for HpSA, 97.6% for HpStAR and 96.3% for ImmunoCard. Eradication therapy was successful in 66 patients and unsuccessful in 16. Sensitivity and specificity of the three stool antigen tests in the post-eradication setting were, respectively, 75.0% and 95.5% for HpSA, 93.8% and 98.5% for HpStAR and 87.5% and 95.5% for Immunocard. Conclusions The performance of all three stool antigen tests in the post-treatment setting was slightly inferior to that of the UBT test and serology, with monoclonal antibody-based tests showing better results.

Inflammation and intestinal metaplasia at the squamocolumnar junction in young patients with or without Helicobacter pylori infection

Background: Intestinal metaplasia (IM) in the oesophagus is a known risk factor for adenocarcinoma of the oesophagus. The incidence of adenocarcinoma of the cardia and oesophagus has increased in Western countries simultaneously with a decrease in Helicobacter pylori prevalence. Aims: To determine the association of H pylori infection with inflammation and IM at the squamocolumnar junction (SCJ) in young individuals. Patients: A total of 168 (121 women; 72%) consecutive outpatients, ≤45 years, undergoing gastroscopy, and with no prior H pylori eradication treatment. Methods: Biopsy specimens taken from the antrum, corpus, SCJ, and oesophagus were assessed according to the updated Sydney system, and type of IM (complete or incomplete) was determined. Serum samples from H pylori positive patients were studied for CagA antibodies. Results: In 86% of 37 patients with gastritis in the antrum and/or corpus (24 histologically H pylori positive) and in 23% of 125 patients with a healthy stomach, inflammation was present in the glandular mucosa at the SCJ. In the latter, cardiac mucosa more often than fundic mucosa at the SCJ was inflamed (p<0.001), the inflammation was usually milder in nature, and was associated with signs of reflux disease. IM (incomplete or complete) at the SCJ was evident in nine of those 24 with a healthy stomach and inflamed cardiac mucosa at the SCJ but in none of those with H pylori gastritis. Conclusions: IM at the SCJ can also appear in young individuals in whom it seems to be associated with reflux related isolated inflammation in cardiac mucosa at the SCJ but not with H pylori gastritis.

Evaluation of a Commercial Immunoblot, Helicoblot 2.1, for Diagnosis of Helicobacter pylori Infection

ABSTRACT The best method to diagnose Helicobacter pylori infection in different clinical situations is controversial. The aim of the study was to assess the performance of a commercial immunoblot, Helicoblot 2.1. The study comprised 215 patients, who were grouped according to the presence of H. pylori infection (assessed by two gastroscopies including histology with a median interval of 7.1 years, enzyme immunoassay [EIA]-based serology, and history of previous H. pylori infections and eradication therapies) into four categories: no H. pylori infection ever, previous infection, ongoing infection, and EIA seropositivity as the only marker of a possible previous infection. The sensitivity of Helicoblot 2.1 to show an ongoing or previous H. pylori infection was 100% and 92%, respectively. Helicoblot 2.1 was negative in only 80% of individuals with no evidence of present or previous infection but in 96% of patients 50 years of age or younger. The current infection marker of the immunoblot was positive in 49% of patients with successful H. pylori eradication therapy. After successful eradication therapy, Helicoblot 2.1 sustained positive results in 87% of patients, and CagA positivity was detected in 87% of patients with follow-up samples for more than 10 years after therapy. Helicoblot 2.1 is a sensitive and, among patients of ages 50 years or younger, a specific test in the primary diagnosis of H. pylori infection. However, it does not discriminate between past and current infections. It can be used in epidemiological studies assessing the role of H. pylori in different late sequelae.

Association of CagA-positive infection with Helicobacter pylori antibodies of IgA class.

cagA gene, the best known virulence factor of Helicobacter pylori, codes for an immunodominant CagA protein. In this study, CagA antibodies of the IgG class were measured by immunoblot or enzyme immunoassay in subjects with positive H. pylori serology, and the presence of CagA antibodies was compared with that of H. pylori antibodies of IgA and IgG classes. Serum samples were available for a total of 1481 subjects, including gastroscopied patients with biopsy-verified H. pylori infection, smoking men with a normal or low serum pepsinogen I level indicating atrophic corpus gastritis, and subjects who later developed gastric cancer and their matched controls. CagA antibodies were significantly more prevalent among individuals with elevated H. pylori antibody titres of the IgA class than in those with IgG antibodies only, with the exception of a small subgroup of individuals who later developed gastric cancer. CagA-positive H. pylori strains seem to induce an immune response with a markedly higher frequency of IgA than what is found in inflammation caused by CagA-negative strains. The presence of serum IgA antibodies to H. pylori seems to indicate a higher risk for CagA-positive H. pylori infection and possibly more severe late sequelae of the disease.

Persisting Chronic Gastritis and Elevated Helicobacter pylori Antibodies after Successful Eradication Therapy

Aim:  The persistence of chronic inflammation in gastric mucosa and elevated Helicobacter pylori antibodies after successful eradication therapy are common findings in clinical practice. We studied their possible association with each other and disappearance in long‐term follow up, as well as their possible connection with gastric atrophy.

Role of earlier gastroscopy in predicting findings on repeat gastroscopy in a population with a low H. pylori prevalence

Objective. Repeat gastroscopy is not recommended for patients without alarm symptoms and with a normal earlier gastroscopy. However, there is little information available on the consequences of this recommendation. The objective of this study was to examine the role of earlier gastroscopy results in predicting the findings at repeat gastroscopy. Material and methods. Patients with previous gastroscopies presenting for a new gastroscopy during 2004–05 were included consecutively. A total of 293 patients who had undergone a gastroscopy a mean of 7.7 years (range 0.6–25.4 years) before the present gastroscopy were included in the study. The patients completed a questionnaire. The associations between the findings of the present gastroscopy and the findings of the previous gastroscopy and other patient characteristics were analysed by stepwise logistic regression. Results. Nine percent of the patients were positive for Helicobacter pylori infection. An abnormal macroscopic finding, defined as any erosion, ulcer or other macroscopic finding with the exception of hiatus hernia, at the repeat gastroscopy was significantly positively associated with: 1) an abnormal finding at a previous gastroscopy (OR 2.94, 95% CI 1.48–5.85), 2) obesity (body mass index, BMI >30) (OR 2.89, 95% CI 1.28–6.55), 3) the presence of alarm symptoms (OR 2.68, 95% CI 1.29–5.56), and negatively associated with 4) the use of proton pump inhibitors (OR 0.48, 95% CI 0.24–0.98). The findings were not associated with age. Conclusions. Abnormal earlier gastroscopy findings, obesity and the presence of alarm symptoms were the strongest indicators of abnormal findings at repeat gastroscopy. Our results support a restrained gastroscopy policy in patients with no alarm symptoms and a normal earlier gastroscopy.

Sequence analysis of the genes encoding for H+/K+-ATPase in autoimmune gastritis.

Background. H+/K+‐ATPase is the target autoantigen in autoimmune gastritis (AIG), an organ‐specific autoimmune disease with a strong hereditary component. Aim. To detect possible polymorphisms in H+/K+‐ATPase α‐ and β‐subunits in AIG patients. Methods. Blood samples from 12 Finnish AIG patients were sequenced for the coding regions of genes encoding for H+/K+‐ATPase α‐ and β‐subunits; 50–52 Finnish anonymous blood donors served as controls. Additionally, parietal cell and Helicobacter pylori antibodies and serum pepsinogen I levels (PG I) were analysed. Results. In the α‐subunit, all patients and controls had C‐allele at the non‐synonymous c.824T>C single nucleotide polymorphism (SNP) resulting in valine substitution for alanine (Val265Ala). In the β‐subunit, a previously unknown non‐synonymous SNP resulting in a substitution of alanine residue for valine (Ala248Val) was found in exon 7 in a single patient and none of the controls. All patients had low serum PG I levels and elevated parietal cell antibodies; three had positive H. pylori serology. Conclusions. At the non‐synonymous SNP c.824T>C in the α‐subunit of H+/K+‐ATPase most Finnish individuals with or without AIG have C allele. Genetic variants of the coding regions of genes for H+/K+‐ATPase α‐ and β‐subunits are not associated with AIG in Finnish patients.