R-dihydrolipoic acid (R-DHLA) and Blood Pressure

Questions: Is there any advantage of using R-dihydrolipoic acid (R-DHLA) over R-lipoic acid (RLA) and is it possible that R-DHLA could increase blood pressure?

Has anyone described the effect of DHLA on have on the angiotensin-renin pathway?

Is there something that can be done to prevent this blood pressure elevation when taking Mito-Gold?

 

 

David Carlson answers: We use R-DHLA to stabilize RLA against polymerization and to increase the bioavailability of RLA over the free-acid form of RLA. I don’t have any information or experience of R-DHLA increasing blood pressure despite the fact I personally consume it nightly in Mito-Gold. We found that R-DHLA is poorly absorbed and extensively metabolized before leaving the gut; therefore most of the health benefits are within the gut (i.e. reduction of postprandial oxidative stress and inflammation). Based on the abstract below, it appears that DHLA should lower blood pressure.

 

Ullian ME, Gelasco AK, Fitzgibbon WR, Beck CN, Morinelli TA. N-acetylcysteine decreases angiotensin (Ang) II receptor binding in vascular smooth muscle cells. J Am Soc Nephrol (2005)16(8):2346-53.

 Abstract: Antioxidants seem to inhibit angiotensin II (Ang II) actions by consuming stimulated reactive oxygen species. An alternative hypothesis was investigated: Antioxidants that are also strong reducers of disulfide bonds inhibit the binding of Ang II to its surface receptors with consequent attenuation of signal transduction and cell action. Incubation of cultured vascular smooth muscle cells, which possess Ang II type 1a receptors, with the reducing agent n-acetylcysteine (NAC) for 1 h at 37 degrees C resulted in decreased Ang II radioligand binding in a concentration-dependent pattern. NAC removal restored Ang II binding within 30 min. Incubation with n-acetylserine, a nonreducing analogue of NAC, did not lower Ang II binding, and oxidized NAC was less effective than reduced NAC in lowering Ang II binding. NAC did not decrease Ang II type 1a receptor protein content. Other antioxidants regulated Ang II receptors differently: alpha-Lipoic acid lowered Ang II binding after 24 h, and vitamin E did not lower Ang II binding at all. NAC inhibited Ang II binding in cell membranes at 21 or 37 but not 4 degrees C. Dihydrolipoic acid (the reduced form of alpha-lipoic acid), which contains free sulfhydryl groups as NAC does, decreased Ang II receptor binding in cell membranes, whereas alpha-lipoic acid, which does not contain free sulfhydryl groups, did not. Ang II-stimulated inositol phosphate formation was decreased by pre-incubation with NAC (1 h) or alpha-lipoic acid (24 h) but not vitamin E. In conclusion, certain antioxidants that are reducing agents lower Ang II receptor binding, and Ang II-stimulated signal transduction is decreased in proportion to decreased receptor binding.