Relations between serum pepsinogen levels, pepsinogen phenotypes, ABO blood groups, age and sex in blood donors

Factors Associated with False Negative Results in Serum Pepsinogen Testing for Precancerous Gastric Lesions in a European Population in the GISTAR Study

The accuracy of plasma pepsinogen (Pg) as a marker for precancerous gastric lesions (PGL) has shown variable results. We aimed to identify factors associated with false negative (FN) cases in Pg testing and to adjust cut-off values for these factors in order to improve Pg yield. Plasma Pg was measured and upper endoscopy with biopsy was performed within the "Multicentric randomized study of Helicobacter pylori eradication and pepsinogen testing for prevention of gastric cancer mortality: the GISTAR study". A multivariable logistic model was built for FN and multiple factors. Values of Pg were compared and sensitivity and specificity were calculated using pre-existing Pg cut-offs for factors showing strong associations with FN. New cut-offs were calculated for factors that showed substantially lower sensitivity. Of 1210 participants, 364 (30.1%) had histologically confirmed PGL, of which 160 (44.0%) were FN. Current smokers, men, and H. pylori positives were more likely FN. Smoking in H. pylori negatives was associated with a higher Pg I/II ratio and substantially lower sensitivity of Pg testing than in other groups. Adjusting Pg cut-offs for current smokers by H. pylori presence improved sensitivity for detecting PGL in this group. Our study suggests that adjusting Pg cut-offs for current smokers by H. pylori status could improve Pg test performance.

Serum pepsinogen II levels are doubled with Helicobacter pylori infection in an asymptomatic population of 40,383 Chinese subjects

Pepsinogen (PG) I and II are crucial in the gastric digestive processes. This study is to examine the relationship of serum PGI, PGII, and PGI/PGII ratio with Helicobacter pylori (Hp) infection, age, sex, and body mass index (BMI) in subjects in Beijing, China.A total of 40,383 asymptomatic subjects, who underwent medical examination in Beijing Rehabilitation Hospital, were included in this study. Serum PG levels were measured using chemoluminescence techniques. The age, sex, and BMI data were collected, and Hp infection was identified with 13C-urea breath test. Statistical analysis was conducted with Python, Pandas and Seaborn software.Asymptomatic subjects with Hp infection (Hp+) had a significantly higher level of PGI in the serum (111 ng/mL [median]) than those without Hp infection (Hp-) (94 ng/mL, P < .001). The asymptomatic Hp+ subjects had 2-fold higher PGII levels (7.2 ng/mL) than Hp- subjects (3.2 ng/mL, P < .001). These changes produced significantly lower PGI/II ratio in Hp+ patients than in Hp- subjects (16:30, P < .001). The serum PGI and PGII levels were higher in males than in females (PGI: 104 ng/mL vs 95 ng/mL, PGII: 4.3 ng/mL vs 3.7 ng/mL, both P < .001), PGI/II ratio of males is at 95% of that in females (P < .001). PGI and PGII levels gradually increased in older people (P < .001), whereas the PGI/II ratio decreased significantly with age (P < .001). The levels of the two serum PGs were decreased and the ratio increased when BMI were higher than 28 kg/cm2 (P < .05).The levels of serum PGI, especial PGII, were increased by Hp infection, and also influenced by age, sex, and BMI. Therefore, these influencing factors should be considered during clinical practice.

Gastric mucosal status in populations with a low prevalence of Helicobacter pylori in Indonesia

In Indonesia, endoscopy services are limited and studies about gastric mucosal status by using pepsinogens (PGs) are rare. We measured PG levels, and calculated the best cutoff and predictive values for discriminating gastric mucosal status among ethnic groups in Indonesia. We collected gastric biopsy specimens and sera from 233 patients with dyspepsia living in three Indonesian islands. When ≥5.5 U/mL was used as the best cutoff value of Helicobacter pylori antibody titer, 8.6% (20 of 233) were positive for H. pylori infection. PG I and II levels were higher among smokers, and PG I was higher in alcohol drinkers than in their counterparts. PG II level was significantly higher, whereas PG I/II ratios were lower in H. pylori-positive than in H. pylori-negative patients. PG I/II ratios showed a significant inverse correlation with the inflammation and atrophy scores of the antrum. The best cutoff values of PG I/II were 4.05 and 3.55 for discriminating chronic and atrophic gastritis, respectively. PG I, PG II, and PG I/II ratios were significantly lower in subjects from Bangli than in those from Makassar and Surabaya, and concordant with the ABC group distribution; however, group D (H. pylori negative/PG positive) was the lowest in subjects from Bangli. In conclusion, validation of indirect methods is necessary before their application. We confirmed that serum PG level is a useful biomarker determining chronic gastritis, but a modest sensitivity for atrophic gastritis in Indonesia. The ABC method should be used with caution in areas with a low prevalence of H. pylori.

Statistical analysis of serum pepsinogen I (PG I) and II (PG II) levels, PG I/PG II ratios and serum gastrin levels in a general population

To allow adoption of serum pepsinogen as a screening indicator of gastric cancer, serum pepsinogen I & II levels, the ratios of PG I / PG II and the serum gastrin levels in a general population were studied using 850 samples selected at random from a rural area in Japan. The collected data were analyzed statistically to determine the distribution characteristics by various categories of sex and age. The following results were obtained:1. The distributions of PG I and PG II, the ratios of PG I/PG II and serum gastrin values largely deviated from the normal distribution. Therefore, the use of non-parametrical methods was recommended for analysis of these data.2. Although no significant difference between all selected men and all selected women was observed in any of the three parameters of PG I and PG II levels and the ratios of PG I / PG II, a significant difference between men and women was observed for PG I levels in under-fifty age groups. On the other hand, the median serum gastrin value (92.0 pg/ml) in all selected men was significantly lower than that (101.0 pg/ml) in all selected women. A statistically significant difference between men and women was observed in serum gastrin levels both in the under-forty age group and in the sixty and over age group.3. No significant difference was observed in the pattern of changes in PG I levels with increasing age in either men or women. While PG II levels in men varied irregularly with advancing age, PG II levels in women showed obvious increases with advancing age. The ratios of PG I / PG II showed a tendency to decrease with advancing age in both men and women. Conversely, serum gastrin levels increased with advancing age in both men and women.

Normal serum pepsinogen I levels in adults: a population-based study with special reference to Helicobacter pylori infection and parietal cell antibodies

OBJECTIVE

Low serum pepsinogen I (PG I) values are common in subjects with advanced corpus atrophy with or without parietal cell antibodies (PCA). Elevated values are usual during Helicobacter pylori infection.

MATERIAL AND METHODS

PG I levels were determined in two randomly selected cross-sectional adult population samples using the Gastroset PGI test kits. The sera (408 in 1973 and 504 in 1994), tested earlier for H. pylori infection and now for PCA, represented subjects living in Vammala, Finland.

RESULTS

In the PCA-negative population, the mean (+/-SD) PG I level was significantly higher in men than in women among both H. pylori-negative (88.13+/-34.16 microg/l versus 72.43+/-29.31 microg/l; p<0.0001) and H. pylori-positive (110.50+/-50.59 microg/l, versus 97.74+/-44.82 microg/l, p<0.0001) subjects; the difference between all H. pylori-positive and -negative subjects was also significant (p<0.001). In the 10-year age groups, age had no impact on the mean PG I levels in H. pylori-negative subjects (p=0.860). In the PCA-positive population, the 10 H. pylori-positive subjects had higher mean PG I levels (112.96+/-53.62 microg/l) than the 13 H. pylori-negative subjects (32.57+/-27.59 microg/l; p=0.002); the latter mean was also significantly lower than that of the PCA- and H. pylori-negative subjects (80.08+/-32.69 microg/l; p<0.0001).

CONCLUSIONS

Men had higher normal PG I values than women, but there was no significant variation by age. H. pylori infection was associated with elevated PG I levels and a small decrease with increasing age. Non-infected PCA-positive subjects showed the lowest mean PG I level.

The epidemiology of low serum pepsinogen A levels and an international association with gastric cancer rates. EUROGAST Study Group

BACKGROUND/AIMS

Low serum levels of pepsinogen A are indicative of chronic atrophy, a risk factor for gastric cancer. This study investigated the relationships between low pepsinogen A levels, Helicobacter pylori seropositivity, and gastric cancer rates in 17 populations worldwide.

METHODS

In each center, about 200 randomly selected subjects (50 male and 50 female, aged 25-34 and 55-64 years) provided serum samples for pepsinogen analysis and H. pylori serology.

RESULTS

Cumulative gastric cancer rates were associated with the prevalence of low pepsinogen A levels in men (coefficient, 0.15 [P = 0.06] for mortality; coefficient, 0.36 [P = 0.01] for incidence) but not women. The prevalence of low pepsinogen A levels was also correlated with H. pylori seropositivity in the older age group (r = 0.55; P = 0.02). Low pepsinogen A levels were significantly more common in the older group (7.5% vs. 2.1% in the younger group; P < 0.001), among women (5.5% vs. 4.1% in men; P = 0.04), and among nonsmokers (5.8% vs. 2.9% in current smokers; P = 0.001).

CONCLUSIONS

Low pepsinogen A levels are more common in areas with a high seroprevalence of H. pylori and in men in areas with high rates of gastric cancer. The prevalence of low pepsinogen A levels increases with age, but the excess in women and nonsmokers could reflect factors other than gastric pathology.

Human pepsinogen A isozymogen patterns in serum and gastric mucosa

The pepsinogen A isozymogen pattern in gastric mucosa is genetically determined and can be visualized in nondenaturating polyacrylamide gel electrophoresis of supernatants of sonified gastric mucosal biopsies by demonstrating proteolytic activity after converting pepsinogen into pepsin by acid. Pepsinogen isozymogens are present in very low concentrations in the blood but can now be demonstrated in serum by a newly developed immunoblotting procedure. This study investigated whether the serum pepsinogen A isozymogen pattern adequately reflects the pepsinogen A phenotype. Serum and gastric mucosal pepsinogen A isozymogen patterns were compared in 72 subjects from the routine endoscopy program. A close correlation was found between the relative intensities of the pepsinogen A isozymogens in the serum and the gastric mucosal patterns. Increasing the pepsinogen A release into the circulation by oral omeprazole did not affect the pepsinogen A patterns in the blood. It is concluded that the serum pepsinogen A pattern reflects the pepsinogen A phenotype in humans. In addition, no preferential release of a pepsinogen A isozymogen into the circulation was observed. Thus, immunoblotting of serum provides a new and reliable tool to study pepsinogen genetics in humans. Because a relationship was previously shown between specific pepsinogen A phenotypes and gastric malignancies in humans, serum pepsinogen A patterns may provide a tool to detect subjects who are at risk of gastric cancers.

Immunoblot technique to visualise serum pepsinogen A isozymogen patterns

Pepsinogen A (PGA) isozymogen patterns in urine and gastric mucosa can be visualised in non-denatured polyacrylamide gel electrophoresis by showing proteolytic activity after the conversion of pepsinogen into pepsin by acid. This method is not suitable for visualising PGA patterns in serum due to low PGA concentrations. To obtain a more sensitive visualisation method an immunoblotting technique was developed. PGA isozymogen patterns from urine and sonified gastric mucosa specimens obtained by immunoblotting were identical with those obtained by activity staining. The immunostaining method was at least 50 times more sensitive. PGA isozymogen patterns could be visualised in serum. Preliminary results suggest that the PGA patterns in serum and gastric mucosa are identical. As an association has been found between the genetically determined PGA isozymogen patterns in gastric mucosa and gastric malignancies in man, immunoblotting of PGA isozymogens in serum may provide a screening tool for subjects at risk of malignant gastric disease.

Discrepancies between gastric mucosal and urinary pepsinogen A patterns and in vitro synthesis and secretion of human pepsinogen

The relationship between electrophoretic pepsinogen A (PGA) patterns from urine and gastric mucosa was studied in healthy volunteers and in patients with various gastric disorders. Discrepancies between urinary and gastric PGA patterns were found in 63.3% of the individuals. In 9% of the subjects with these discrepancies, the phenotype class in urine was different from that in gastric mucosa. The differences were found in all diagnostic groups. The highest frequency of differences was found in patients with gastric ulcer. The differences were not related to the serum PGA level. More than 80% of the differences were caused by a lower relative intensity of pepsinogen A fraction 5 (Pg5) in urine than in gastric mucosa. The possible origin of differences in PGA isozymogen patterns was studied by organ culture of gastric biopsies. In vitro synthesis and secretion of pepsinogens were studied by electrophoresis and autoradiography. The synthesis rate of PGA in biopsies of 1-2 mm diameter was 40-100 ng/hr. Posttranslational modification of PGA isozymogens was demonstrated. Pg2 and part of Pg4 probably are secondary products of Pg3 and Pg5, respectively. In some individuals the secretion rate of Pg3 was low compared to the other isozymogens. The conversion of Pg3 into Pg2 and the differential secretion of the isozymogens may explain some of the discrepancies between gastric and urinary PGA patterns.

Immunohistochemical localization of pepsinogen A and C containing cells in Barrett's oesophagus

No data are available on the localization of Pepsinogen A (PGA = PG I) and Pepsinogen C (PGC = PG II) positive cells in Barrett's epithelium. Endoscopic biopsy specimens were taken from the columnar epithelium from 23 patients (n = 93), and in addition from the cardia from eight healthy control subjects (n = 38). The tissue was stained by the immunoperoxidase technique with specific anti-pepsinogen antisera, and double immunostained for PGA and PGC. In the Barrett's epithelium PGA was found in 28 out of 93 biopsy specimens (30.1%) and PGC in 55 out of 93 (59.1%). Chief cells always stained both for PGA- and PGC +. PGA + and PGC + cells were found each in 100% of the biopsy specimens with fundic type epithelium, in 21.7% and 70.7% of biopsy specimens with junctional type, in 0% and 26.1% of biopsy specimens with specialized epithelium and in 12.5% and 43.5% of biopsy specimens with mixed junctional/specialized features respectively. Dysplastic epithelium stained always negatively with both anti-pepsinogen antisera. In most control cardia biopsy specimens PGA as well as PGC were demonstrable; occasionally clear mucous glands were PGA - and PGC+. It is concluded that pepsinogen-containing cells can be accurately identified in the Barrett's epithelium; their presence seems related to the histological cell type. Identification of pepsinogen positive cells may contribute to a more accurate morphological classification of the Barrett's epithelium.

Twin studies on urinary pepsinogen A phenotypes and serum pepsinogen A levels

Urinary pepsinogen A (PGA or PG I) phenotypes and serum PGA levels were studied in MZ and DZ twins and their parents. In 45 out of 48 MZ twin pairs PGA patterns were completely identical, while 3 MZ twin pairs showed minor differences in the relative intensity of the Pg5 isozymogen. This suggests that the intensity of this isozymogen may be influenced by nongenetic factors. There was little difference in the interclass correlations of serum PGA levels between MZ and DZ twins, indicating a large contribution of common environmental factors to serum PGA levels. This is in contrast with previous studies.

Clinical significance of pepsinogen A isozymogens, serum pepsinogen A and C levels, and serum gastrin levels

Gastric mucosal pepsinogen A phenotype, serum pepsinogen A level, serum pepsinogen C level, serum pepsinogen A/pepsinogen C ratio, and serum gastrin level were evaluated as potential markers for gastric cancer or its precursors in 19 healthy volunteers and 341 patients from the gastroscopy program. Gastric cancer, atrophic gastritis, and intestinal metaplasia of the stomach were associated with pepsinogen A phenotypes, characterized by an intense fraction 5, and with a low serum pepsinogen A level (less than 25 micrograms/l), a low serum pepsinogen A/pepsinogen C ratio (less than 1.5), and a high serum gastrin level (greater than 79 ng/l). The specificity of pepsinogen A phenotypes with an intense fraction 5 for gastric cancer or its precursors was 95.1% with a sensitivity of 20.4%. The sensitivity and specificity of the noninvasive tests were evaluated with the receiver operating characteristic. For clinical purposes, a serum pepsinogen A/pepsinogen C ratio less than 1.8 is the most suitable test, with a sensitivity of 74% and a specificity of 76% for gastric cancer or its precursors, with a reference population of patients with benign gastric disorders. However, the sensitivity and specificity of the single or combined tests are too low for population screening purposes.

Pepsinogen A polymorphism in gastric mucosa and urine, with special reference to patients with gastric cancer

Electrophoretic pepsinogen A patterns were determined in gastric fundic mucosa biopsies from 601 patients with various gastric disorders and 25 healthy volunteers. Pepsinogen A patterns with an intense fraction 5 appeared to be associated with gastric cancer and premalignant changes of the stomach (p less than 10(-9)). In 60 individuals pepsinogen A patterns were determined in normal mucosa from different parts of the stomach. No differences were found between these patterns. In 29 out of 59 gastric cancer patients pepsinogen A could be demonstrated in the macroscopically malignant tissue. In two cases a different pattern compared with uninvolved fundic mucosa was observed. During a follow up study, major changes in the pepsinogen A pattern were observed in 7 out of 56 patients. In 8.6% of the examined patients urinary pepsinogen A patterns differed considerably as compared with the pattern observed in the gastric fundus. The results suggest that the highly significant association between intense Pg5 (the product of the D gene) and gastric cancer or its precursors may be caused by genetic as well as non-genetic factors.