(Abstract 314), Journal of Heart Disease. 4: 2005;79.
A THERAPEUTIC STRATEGY USING SUBCUTANEOUS MAGNESIUM TO REDUCE SPACE FLIGHT
ISCHEMIC INJURIES
The
objective, to provide magnesium (Mg.) therapy for space flights (SF),
thereby reducing potential ischemic complications. Mg. reservoir
depletion in skeletal muscle and bone and malabsorption
are responsible for SF-related Mg. deficits, conducive to arrhythmias
(AR), shown in humans (H), calcium (Ca.) overload of mitochondria, endothelial
injuries (EI) in rodents, and oxidative stress shown in both. Clinorotation
of cultured human endothelial cells (simulating microgravity) show decreased
proliferative activity and thinning of actin
filaments (impaired motility). Invariable dehydration,
insulin resistance, space walks (SW)- sinus tachycardia (over 160/ min.),
decreased Mg., cyclic GMP, vascular endothelial growth factor (VEGF),
platelets, and elevations of catecholamines, angiotensin, aldosterone, cytokines, have all been shown in H. Irwin (Apollo
15) had AR, described classical angina with severe dyspnea
during reentry (7 Gs).It's been postulated that there may be SF-intracellular
shift of Ca induced by high ambient C02(0.5-0.7%). For total over
2 hours, prior and during SW up to 8 Hr., 100% oxygen is required. Because
of SF -malabsorption and potential renal, hepatic
dysfunction, and deterioration of some pharmaceuticals (P), their use
is limited. Mg., an antioxidant, Ca. blocker,
simulates VEGF and induces nitric oxide synthesis. Stable subcutaneous
Mg 1-aspartate-hydrochloride is available. A dependable, replenishable delivery device must be developed.
Intracellular Mg. levels should be monitored
from sublingual cells by X-ray dispersion. A strategy is proposed, monitoring
and correcting SF - Mg deficits, partially compensating for problems with
P, reducing potential oxidative stress, Ca. overload, AR, EI.