Diamine Oxidase Activity Levels Research Articles

Lactiplantibacillus plantarum BW2013 protects mucosal integrity and modulates gut microbiota of mice with colitis.

This study explored the effects of Lactiplantibacillus plantarum (previously Lactobacillus plantarum) BW2013 on mucosal integrity and gut microbiota of mice with dextran sulfate sodium (DSS)-induced colitis. The results show that the clinical symptoms in DSS-modelled ulcerative colitis (UC) were improved by L. plantarum BW2013 via decreasing disease activity index scores and suppressing inflammatory cell infiltration. Furthermore, L. plantarum BW2013 decreased the levels of diamine oxidase activity, myeloperoxidase, and D-lactic acid. The mRNA expression of ZO-1, occludin, and claudin-1 was upregulated by L. plantarum BW2013, which also increased IL-10 and reduced TNF-α, IL-1β, and IL-6 in the colon. 16S rDNA sequencing showed that L. plantarum BW2013 enhanced α-diversity. L. plantarum BW2013 upregulated significantly the abundance of unidentfied Lachnospiraceae, Lactococcus, Rikenella, Lactobacillus, and Odoribacter, which had an inhibitory effect on inflammation and a protective effect on the integrity of the mucosa. These results demonstrate that L. plantarum BW2013 alleviates DSS-modelled UC by protecting mucosal integrity and ameliorating the composition of gut microbiota.

Diamine oxidase as a marker of intestinal mucosal injury and the effect of soluble dietary fiber on gastrointestinal tract toxicity after intravenous 5-fluorouracil treatment in rats

The level of plasma diamine oxidase (DAO) activity is associated with the maturation and integrity of small intestinal mucosa. This study in rats investigated whether a decreased level of plasma DAO could reflect the severity of mucosal injury due to intravenous 5-fluorouracil (5-FU) treatment. The beneficial effect of soluble dietary fiber (SDF) on preventing diarrhea after 5-FU treatment was also examined. To induce diarrhea, 5-FU (50 mg/kg/day for four days) was administered via the tail vein with or without SDF supplementation. After 5-FU treatment, the majority of rats developed moderate to severe diarrhea, and levels of plasma DAO activity significantly decreased compared to those of control group (P < 0.05). Scanning electron microscopy revealed disarrangement of the small intestinal villi. Contrarily, the rats supplemented with SDF had diarrhea less frequently (50.0 vs. 91.7 %, P = 0.025) on day five, and DAO activity levels were significantly higher than in those rats administered 5-FU alone (8.25 ± 5.34 vs. 5.50 ± 4.32, P = 0.023). In conclusion, plasma DAO activity decreases in response to severe intestinal mucosal injury after 5-FU treatment, and SDF supplementation might be a practical and useful treatment for reducing the intestinal toxicity of 5-FU.

Effects of Cold Hardening on the Regulation of Polyamine Levels in Wheat (Triticum aestivum L.) and Alfalfa (Medicago sativa L.)

When leaves of wheat (Triticum aestivum L.) are exposed to a cold hardening temperature, a major accumulation of putrescine (6-9 times) takes place. Spermidine accumulates to a lesser extent and, conversely, spermine decreases slightly. These variations are completely reversible when plants are returned to initial growing conditions. A similar response is obtained with crowns. During cold hardening, arginine decarboxylase activity remains near its initial level while a considerable loss of activity is observed in control plants. Ornithine decarboxylase and diamine oxidase activity levels are not substantially modified by the treatment. Alfalfa (Medicago sativa L.) also accumulates putrescine under low temperature stress, indicating that this phenomenon is not typical of cereals. The physiological significance of this accumulation of putrescine is still unexplained but the results obtained suggest the involvement of polyamines in the biochemical processes of cold hardening.

Diamine oxidase (histaminase). A circulating marker for rat intestinal mucosal maturation and integrity.

Diamine oxidase (histaminase) is an enzyme found in high concentrations in the intestinal mucosa of humans and other mammalian species. We investigated whether plasma and mucosal levels of diamine oxidase activity reflect both the maturational status of the mucosa during its development in the newborn rate and the degree of mucosal damage during its injury in the adult rat. Litter mates were reared under identical conditions and killed at different ages from day 0 to day 40 after birth. Diamine oxidase in the small intestine was low at birth, increased gradually with age, reached a peak at 22 d, and then remained at normal adult levels, similar to the developmental patterns of maltase and sucrase. Plasma diamine oxidase rose in parallel with intestinal levels (n = 500, r = 0.84, P less than 0.001), reached a peak at 24 d, and then remained at normal adult levels. Diamine oxidase activity in 15 nonintestinal tissues was less than 5% of ileal mucosal activity, and no nonintestinal activities showed increase with age. Adult rat intestinal loops were perfused with hyperosmolar sodium sulfate solutions to produce selective damage to villus mucosa. With increasing mucosal damage, there was a progressive decrease in the enzyme activities studied; first, lactase levels fell, then maltase and sucrase, and finally mucosal and plasma diamine oxidase activity levels fell. The decrease in plasma diamine oxidase reflected the degree of mucosal damage (n = 29, P less than 0.04). Diamine oxidase activity is thus unique among intestinal mucosal enzymes studied to date in that circulating levels can serve as a marker of mucosal maturation and integrity.

Biosynthesis and metabolism of putrescine in the rat placenta

High levels of ornithine decarboxylase are found in the developing rat placenta. Peak activities are observed around day 17 of pregnancy, after which there is a slight decline in activity up to the time of parturition. Most of the ornithine decarboxylase activity is found in the fetal placenta, whereas in the maternal placenta the activity declines steadily throughout the latter part of pregnancy. At term over 90 per cent of the placental ornithine decarboxylase is found in the fetal segment. The putrescine content of the fetal placenta is three to ten times higher than that of the maternal tissue from day 15 onward. In contrast to the pattern of distribution for ornithine decarboxylase, diamine oxidase is found mainly in the maternal placenta, and the activity remains high throughout pregnancy. S-adenosyl methionine decarboxylase is also present in the placenta with significantly higher levels being found in the fetal tissue. The activity of this enzyme, however, was at all times much lower than that of ornithine decarboxylase and diamine oxidase. The alignment of the metabolic pathways favoring the metabolism of putrescine via oxidative deamination rather than through conversion to spermidine suggests that putrescine may have a role to play in the developing rat placenta. The results also indicate that the high levels of diamine oxidase activity found in the placenta are probably associated more with putrescine than with histamine metabolism.