Effect of ulceration on rat gastric tissue polyamine contents in response to different procedures; inhibition of these effects by cimetidine

Causality of Blood Metabolites on Proliferative Diabetic Retinopathy: Insights From a Genetic Perspective

Background: Our goal was to examine the causal link between blood metabolites, their ratios, and the risk of developing proliferative diabetic retinopathy (PDR) from a genetic insight. Methods: Summary-level data about 1400 blood metabolites and their ratios, as well as PDR, were sourced from prior genome-wide association studies (GWAS). A two-sample univariate and multivariate Mendelian randomization (MR) approach was utilized. Additionally, metabolic pathway analysis and sensitivity analysis were also conducted. Results: After adjusting for multiple tests, four blood metabolites significantly correlated with PDR risk. Two ceramides, including glycosyl-N-palmitoyl-sphingosine (d18:1/16:0) (odds ratio [OR] = 1.12, 95% confidence interval (CI): 1.06-1.17, p < 0.001, false discovery rate (FDR) = 0.005) and glycosyl-N-behenoyl-sphingadienine (d18:2/22:0) (OR = 1.11, 95% CI: 1.06-1.16, p < 0.001, FDR = 0.017), were linked to increased risk. Additionally, 3-methylcytidine (OR = 1.05, 95% CI: 1.03-1.08, p < 0.001, FDR = 0.021) also posed a risk, whereas (N(1)+N(8))-acetylspermidine (OR = 0.91, 95% CI: 0.87-0.94, p < 0.001, FDR = 0.002) appeared protective. Multivariable MR analysis further confirmed a direct, protective effect of (N(1)+N(8))-acetylspermidine on PDR risk (OR = 0.94, 95% CI: 0.89-1.00, p = 0.040). The sensitivity analysis results indicated that evidence for heterogeneity and pleiotropy was absent. Conclusion: These metabolites have the potential to be used as biomarkers and are promising for future research into the mechanisms and drug targets for PDR.

Modulation of indomethacin-induced gastric injury by spermine and taurine in rats

This study investigated the involvement of neutrophil infiltration, nitric oxide (NO) generation, and oxidative stress in indomethacin-induced ulcer and the possible gastroprotective potentials of spermine and taurine, known for their tissue regenerating and antioxidant effects, respectively. Male Wistar albino rats (180-220 g) were allocated into a normal control group, ulcer control group (received a single dose of indomethacin 40 mg-kg p.o.), and two ulcer groups pretreated with spermine (150 mg-kg p.o. 1 h before ulcer induction) and taurine (250 mg-kg i.p. for three consecutive days before ulcer induction). The animals were killed 6 h after indomethacin administration, and the gastric juice, serum, and mucosal tissue were used for gastric injury evaluation. Both modulators significantly ameliorated the indomethacin-induced gastric lesions in glandular mucosa. Notably, spermine exhibited the most pronounced effect as manifested by great reduction in the gastric ulcer index, normalization of the elevated gastric acidity, and triggering of mucin production. Spermine and taurine were able to decrease the elevated levels of gastric myeloperoxidase, conjugated diene, and serum NO. However, the lowered tissue NO content was markedly elevated only by taurine. The antioxidant action of taurine was illustrated by restoration of the depressed content of glutathione, normalization of the inhibited activities of glutathione reductase, and superoxide dismutase. These results suggest that spermine and taurine confer significant gastroprotection against indomethacin-induced gastric injury with the priority of spermine.

Biogenic amines and polyamines: similar biochemistry for different physiological missions and biomedical applications

Biogenic amines are organic polycations derived from aromatic or cationic amino acids. All of them have one or more positive charges and a hydrophobic skeleton. Nature has evolved these molecules to play different physiological roles in mammals, but maintains similar patterns for their metabolic and intracellular handling. As deduced from this review, many questions still remain to be solved around their biochemistry and molecular biology, blocking our aims to control the relevant pathologies in which they are involved (cancer and immunological, neurological, and gastrointestinal diseases). Advances in this knowledge are dispersed among groups working on different biomedical areas. In these pages, we put together the most relevant information to remark how fruitful it can be to learn from Nature and to take advantage of the biochemical similarities (key protein structures and their regulation data on metabolic interplays and binding properties) to generate new hypothesis and develop different biomedical strategies based on biochemistry and molecular biology of these compounds.