Effects of taurine on the reactivity of aortas from diabetic rats.
Level 5 - mechanism / opinion, no new human data
Preclinical in vitro animal tissue experiment (CEBM Level 5).
PubMed 18174109 · doi:10.1016/j.lfs.2007.11.012
What was done
Researchers isolated aortic rings from male rats with streptozotocin-induced chronic diabetes and control rats to evaluate in vitro vascular reactivity. Contractile responses to norepinephrine and KCl, along with calcium influx, calcium release, and protein kinase C-mediated pathways, were tested in endothelium-denuded rings after 2-hour incubation with 5 mM or 10 mM taurine. Endothelium-dependent relaxation to acetylcholine was also measured. Additionally, nondiabetic aortic rings were exposed to 45 mM glucose for 3 hours with or without 5 to 10 mM taurine to evaluate phenylephrine-induced contraction and acetylcholine-mediated relaxation.
What was found
In diabetic aortic rings, contractile responsiveness to norepinephrine was increased compared to controls, whereas response to KCl was unaffected. Incubation with 10 mM, but not 5 mM, taurine reduced norepinephrine-induced hypercontractility back toward control levels and inhibited associated intracellular calcium release, extracellular calcium influx, and protein kinase C activation. Endothelium-dependent relaxation to acetylcholine was impaired in diabetic aortas and was ameliorated close to control levels by 10 mM taurine. In nondiabetic rings, 45 mM glucose increased phenylephrine contraction and impaired acetylcholine relaxation, both of which were concentration-dependently reduced by 5 to 10 mM taurine. The abstract reported no exact numerical values, effect sizes, or p-values.
Why it matters
This study demonstrates that taurine can directly counteract acute hyperglycemia- and diabetes-induced vascular smooth muscle hypercontractility and endothelial dysfunction in isolated rat tissue through calcium- and protein kinase C-dependent mechanisms.
Limits
The findings are limited to in vitro rat aortic preparations and acute exposure conditions, which do not reflect chronic in vivo hemodynamics, human vascular physiology, or oral pharmacokinetics. The abstract reports no sample sizes for animals or tissue rings and provides no quantitative data or confidence intervals.
Cited by
- supports Taurine is involved in cellular calcium regulation, including in arterial wall muscle cells and blood platelets.