Performance evaluation of a novel 14C-urea breath test (solid scintillation) for the diagnosis of helicobacter pylori infection.

14C-urea breath tests (UBTs) can be used to diagnose helicobacter pylori (H. pylori) infection. This study aimed to evaluate the accuracy of a solid scintillation 14C-UBT in diagnosing H pylori infection. This open-label, prospective multicenter study enrolled patients who underwent H pylori screening from January 7, 2020, to October 28, 2020, in 3 centers in China. All participants underwent solid scintillation UBT first and then gastroscopy. The rapid urease test and histological examination results were the gold standards (H pylori-positive was defined as the 2 tests being positive; H pylori-negative was defined as both tests being negative). The solid scintillation 14C-UBT involves a scintillation sampling bottle and a 14C-urea capsule. The sampling bottle contains a stack of carbon dioxide-absorbing and scintillation sheets. The test is read using a photomultiplier. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for H pylori infection were evaluated. This study enrolled 239 participants. There were 98 males and 141 females, aged 45.8 ±â€…11.9 (range: 21-66) years. Thirty-four participants were excluded due to a discrepancy between the rapid urease test and immunohistochemistry examination. Finally, 205 participants were included in the analysis. According to the gold standard, 87 out of 205 (42.4%) participants were H pylori-positive. Compared with the gold standard, the sensitivity, specificity, accuracy, and positive and negative predictive values of the solid scintillation 14C-UBT were 95.4%, 97.5%, 96.6%, 96.5%, and 96.6% for the solid scintillation UBT, respectively. One participant experienced 1 adverse event (AE) (exacerbation of chronic cholecystitis), and the AE eventually improved by itself. The investigators determined that the AE was unrelated to the study device. The noninvasive solid scintillation 14C-UBT has a high diagnostic value for H pylori infection, comparable to the diagnostic value of the gold standard.

Downregulation of tumor suppressor RACK1 by Helicobacter pylori infection promotes gastric carcinogenesis through the integrin ß-1/NF-κB signaling pathway.

Receptor of activated protein kinase C 1 (RACK1) is downregulated in gastric cancer and is involved in modulating NF-κB signaling pathway activity. However, the underlying molecular mechanisms regulating RACK1 expression are unclear. In this study, we demonstrated that downregulated expression of RACK1 was observed in gastric cancer tissue compared to adjacent normal tissue and was correlated with poor prognosis in patients. Helicobacter pylori (H. pylori) infection downregulated RACK1 expression in concert with canonical NF-κB signaling pathway activation in vivo and in vitro. RACK1 overexpression suppressed NF-κB signaling pathway activation as well as the release of downstream proinflammatory cytokines. In addition, RACK1 downregulation increased integrin ß-1 expression, while integrin ß-1 silencing decreased NF-κB signaling activation. Moreover, H. pylori infection downregulated RACK1 but upregulated integrin ß-1 expression at the precancerous lesion stages in human subjects. Our data indicate that H. pylori infection promotes the upregulation of integrin ß-1 expression via downregulation of RACK1 expression, which subsequently leads to the elevated activation of the NF-κB signaling pathway, an essential step in H. pylori-induced carcinogenesis.