Michaela Lellig (Aachen / DE), Juan Muñoz-Castañeda (Cordoba / ES), Juliane Hermann (Aachen / DE), Heidi Noels (Aachen / DE), Mariano Rodríguez (Cordoba / ES), Joachim Jankowski (Aachen / DE), Vera Jankowski (Aachen / DE)
Abstract-Text (inkl. Referenzen und Bildunterschriften)
Introduction: Although hypertension is a worldwide health problem, treatment options in low-income countries are still limited. Therefore, finding a drug that is affordable and accessible to patients in these countries is an urgent need. Since angiotensin II (Ang II) is one of the essential vasoconstrictive peptides in the human organism, we analyzed the impact of its posttranslational modification to pyruvamide-Ang II (Ang P) by pyridoxal-5"-phosphate, a less expensive vitamin B6 derivative, on blood pressure.
Methods: The posttranslational modification of Ang II to Ang P by pyridoxal-5"-phosphate was investigated by mass spectrometry. Calcium ion influx into vascular smooth muscle cells (VSMC) treated with Ang II or Ang P, respectively, was investigated in vitro. In ex vivo experiments, the vasoconstrictive effect of Ang II and Ang P was analyzed by using a bioassay of isolated perfused rat kidneys. Furthermore, Ang II and Ang P were investigated in in vivo experiments. Both Wistar Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) were treated with pyridoxal-5"-phosphate. Blood pressure was measured time-dependently.
Results: Calcium ion influx in VSMC after stimulation with Ang P was significantly decreased compared to Ang II. Perfusion pressure of isolated perfused rat kidney increased less by Ang P than by Ang II. The systolic and diastolic blood pressure of SHR treated with pyridoxal-5"-phosphate decreased from 171/139 ± 5 mmHg to 129/98 ± 2 mmHg after three days. The blood pressure of WKY treated with Ang II increased to 167/133 ± 3 mmHg, while the blood pressure of WKY treated with Ang II and pyridoxal-5"-phosphate decreased to 129/99 ± 2 mmHg.
Conclusions: Pyridoxal-5"-phosphate significantly decreased blood pressure in SHR and WKY, and might be a cost-effective drug against hypertension. Respectively, a recommendation for an increased nutritional vitamin B6 intake might have a decreasing effect on blood pressure in the hypertensive population.