Changes with aging in gastric biomarkers levels and in biochemical factors associated with Helicobacter pylori infection in asymptomatic Chinese population

AIM To observe changes in gastric biomarker levels with age and effects of Helicobacter pylori(H. pylori) infection in a healthy population, and explore factors associated with gastric biomarkers.METHODS Three hundred and ninety-five subjects were selected and underwent physical examinations, biochemical tests, and measurement of serum pepsinogen(PG)Ⅰ and Ⅱ, gastrin-17(G-17) and H. pylori antibody levels. Analyses were made by Student's t-test, ANOVA, Pearson's correlation and multiple linear regressions.RESULTS PGII levels were higher in the ≥ 65-years-old age group(P < 0.05) and PGI/PGII were lower in the ≥ 75-years-old age group(P = 0.035) compared to the 35-44-years-old age group. Levels of low-density lipoprotein cholesterol(LDL-C) were higher(P = 0.009) in H. pylori-infected subjects that were male. LDL-C levels were higher in 55-74-years-old age group(P < 0.05) for H. pylori-infected subjects and 45-64-yearsold age group(P < 0.05) for non-infected subjects compared to 35-44-years-old age group. Hp-Ig G level positively correlated with PGⅠ, PGⅡ and G-17(P < 0.001, P < 0.001, P = 0.006), and negatively correlated with PGI/PGII(P < 0.001). Creatinine positively correlated with PGⅠ, PGⅡ and G-17(P < 0.001, P < 0.001, P < 0.001). Fasting blood glucose(FBG) positively correlated with PGⅠ/PGⅡ and G-17(P < 0.001, P = 0.037). Age positively correlated with PGII and G-17(P = 0.005, P = 0.026).CONCLUSION PGII levels increased while PGI/PGII declined with age in a healthy population. H. pylori infection had an effect on raising LDL-C levels to increase the risk of atherosclerosis in males, especially those of elderly age. Age, H. pylori infection, levels of renal function and FBG were associated with levels of pepsinogens and gastrin.

Increased susceptibility of aging gastric mucosa to injury:The mechanisms and clinical implications

This review updates the current views on aging gastric mucosa and the mechanisms of its increased susceptibility to injury. Experimental and clinical studies indicate that gastric mucosa of aging individuals-&#x0201c;aging gastropathy&#x0201d;-has prominent structural and functional abnormalities vs young gastric mucosa. Some of these abnormalities include a partial atrophy of gastric glands, impaired mucosal defense (reduced bicarbonate and prostaglandin generation, decreased sensory innervation), increased susceptibility to injury by a variety of damaging agents such as ethanol, aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs), impaired healing of injury and reduced therapeutic efficacy of ulcer-healing drugs. Detailed analysis of the above changes indicates that the following events occur in aging gastric mucosa: reduced mucosal blood flow and impaired oxygen delivery cause hypoxia, which leads to activation of the early growth response-1 (egr-1) transcription factor. Activation of egr-1, in turn, upregulates the dual specificity phosphatase, phosphatase and tensin homologue deleted on chromosome ten (PTEN) resulting in activation of pro-apoptotic caspase-3 and caspase-9 and reduced expression of the anti-apoptosis protein, survivin. The imbalance between pro- and anti-apoptosis mediators results in increased apoptosis and increased susceptibility to injury. This paradigm has human relevance since increased expression of PTEN and reduced expression of survivin were demonstrated in gastric mucosa of aging individuals. Other potential mechanisms operating in aging gastric mucosa include reduced telomerase activity, increase in replicative cellular senescence, and reduced expression of vascular endothelial growth factor and importin-&#x003b1;-a nuclear transport protein essential for transport of transcription factors to nucleus. Aging gastropathy is an important and clinically relevant issue because of: (1) an aging world population due to prolonged life span; (2) older patients have much greater risk of gastroduodenal ulcers and gastrointestinal complications (e.g., NSAIDs-induced gastric injury) than younger patients; and (3) increased susceptibility of aging gastric mucosa to injury can be potentially reduced or reversed pharmacologically.

Extract from Zanthoxylum piperitum Induces Apoptosis of AGS Gastric Cancer Cells through Akt/MDM2/p53 Signaling Pathway

Objective:To determine the effect of Zanthoxylum piperitum extracet(ZPE)on apoptosis and analyze anticancer substances in ZPE,changes in proteins related to apoptosis,and pathological changes in tumors in mouse.Methods:Fifteen 4-week-old female BALB/c nu/nu mice were divided into 3 groups depending on ZPE dose,with 5 in each group.AGS gastric carcinoma cells(1 x 10^(6) cells/200 jxL)were subcutaneously injected into the flank of each mouse.One week after the injection of AGS cells,ZPE was administered to the skin tissue[10 or 50 mg/(kg-d)]in the low-and high-dose groups,respectively for 20 days.Control animals were injected with vehicle only.After 3 weeks,the tumor was extracted and carried out for immunohistochemistry,the tendency of apoptosis and p53 in the body was checked using TdT-mediated dUTP nick-end labeling(TUNEL)assay.For 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)assay,annexin V dead cell staining,cell cycle arrest and Western blotting,AGS gastric carcinoma cells were incubated with various concentrations of ZPE for 24 h.Cell survival rates were analyzed by MTT assays.Apoptosis was analyzed using annexin V dead cell staining and cell cycle arrest and measured using Muse cell analyzer.Results:High performance liquid chromatography(HPLC)analysis showed that ZPE contained organic sulfur compounds such as alliin and S-allylcysteine.MTT assay results revealed that ZPE(10-85»xg/mL)could effectively inhibit the growth of AGS gastric cancer cells at higher concentrations(P<0.05,P<0.01).The annexin V&dead cell staining assay and cell cycle arrest assay confirmed a dose-dependent increase in the apoptosis rate and G!phase in ZPE(10-70 jig/mL)groups.ZPE decreased the expression of anti-apoptotic proteins(p-Akt,p-MDM2,Bcl-2),while increased pro-apoptotic proteins(cleaved PARP,p53,pro-Caspase 3,Bax).TUNEL assays revealed an increase in cell apoptosis.Immunohistochemistry staining confirmed the involvement of p53.Conclusion:ZPE decreases AGS cell proliferation and induces apoptosis by inhibiting Akt and MDM2 expression.