Shimane University

Aging-related cognitive decline is a major concern in aging societies. Theobromine (TB), a cacao-derived methylxanthine, exerts neuroprotective effects through anti-inflammatory, antioxidant, and neurotrophic mechanisms; however, its efficacy in aging models remains unclear. This study investigated the mechanisms underlying neuroprotective effects of chronic TB administration in senescence-accelerated mouse prone 8 (SAMP8), a model of age-related memory impairment. SAMP8 and SAMR1 mice were fed either a control diet or a diet supplemented with 0.05% TB for 50 d. Cognitive performance was evaluated by the novel object recognition (NOR) test. Neurotrophic factors (BDNF and NT-3), synaptic proteins (PSD95 and synaptophysin), and plasticity-related signaling molecules (phosphorylated CREB and TrkB) were analyzed in the prefrontal cortex and hippocampus. Inflammatory cytokines, lipid peroxides, and antioxidant enzymes were quantified. Molecular docking was used to assess TB's interaction with phosphodiesterase (PDE) enzymes. TB improved short-term memory in SAMP8, increasing discrimination index in the NOR test. This was accompanied by increased BDNF, NT-3, PSD95, and synaptophysin levels and enhanced CREB and TrkB phosphorylation. Furthermore, TB lowered the levels of pro-inflammatory cytokines (IL-1β, TNF-α) and phosphorylated NF-κB, reduced lipid peroxidation, and increased the levels of antioxidant markers (HO-1, GSH). These effects were minimal in SAMR1. No adverse effects on body weight or blood parameters were observed. Molecular docking indicated that TB binds to PDE enzymes with weaker inhibitory activity than selective inhibitors. TB enhances short-term memory and synaptic function in aged mice via neurotrophic, antioxidant, and anti-inflammatory mechanisms, supporting its potential as a safe dietary intervention for age-related cognitive decline.

Recent reports have suggested the widespread distribution of a novel form of plastic waste on marine shorelines; plastics seemingly originating from the burning and melting of plastic waste. These plastics, termed pyroplastics, were collected in the intertidal zone of beaches on the Sea of Japan coastline and analyzed for their composition. Despite their unknown origins, these pyroplastics are a ubiquitous presence along the Sea of Japan coast. A total of 146 pyroplastics were found with the highest occurring at Koura, the enclosed bay site, with 2.1 pyroplastics/m² and the lowest at Chirihama, the site furthest north, with 0.3 pyroplastics/m². Among these were mixtures of plastic polymer types, which included the most commonly used plastics: polyethylene, polypropylene and polystyrene. Most samples did not show signs of colonization by marine organisms, suggesting a greater likelihood of being produced and transported locally. Still, there are various aspects to these novel plastic types that are unknown, specifically with respect to their toxicity and their propensity to fragment into microplastics.

The incidence of Helicobacter pylori (Hp)-naïve gastric neoplasms (HpNGNs) is increasing due to a growing Hp-naïve population and improved recognition. Among these, HpNGNs that predominantly exhibit foveolar-cell differentiation include foveolar-type gastric adenomas (FGA) and fundic gland polyps with dysplasia (FGPD). Traditionally, FGAs have been considered large, whitish, flat lesions (flat-type FGA), primarily associated with syndromic conditions, such as familial adenomatous polyposis (FAP) and gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS), while sporadic cases are rare. This type exhibits a gastric immunophenotype with diverse differentiation, mainly toward foveolar cells, and harbors APC and KRAS mutations in all sporadic and most syndromic cases. A distinct subset of FGAs, termed foveolar-type gastric adenoma with a raspberry-like appearance (FGA-RA), has been identified. It presents as small, reddish polyps with unique macroscopic and microscopic features and only occurs sporadically. FGA-RA often mimics gastric hyperplastic polyps macroscopically and typically exhibits low-grade dysplasia, making biopsy-based diagnosis challenging and leading to its historical underrecognition. It shows pure foveolar differentiation and consistently harbors Krüppel-like factor 4 (KLF4) mutations. FGPD primarily develops sporadically in Hp-naïve individuals with long-term proton pump inhibitor use. A syndromic form, resembling flat-type FGAs, is also associated with FAP and GAPPS. Histologically, FGPD features dysplasia confined to the superficial foveolar epithelium and mucus neck cells overlying fundic gland polyps, with APC mutations detected in approximately 50% of cases. This review explores the clinicopathological and molecular characteristics of HpNGNs with predominant foveolar cell differentiation, emphasizing the need for an updated histological diagnostic framework.