ascorbic-acid and Aortic-Aneurysm

The approximately 4000 'normal' mammals that synthesize ascorbic acid produce on average circa 50 mg/kg per day routinely. Although humans have the same needs as normal mammals, they do not produce ascorbic acid at all and, on average, ingest only circa 1 mg/kg per day. The normal mammals' much larger production enables them to continually renew structural proteins, including both collagen, a flexible but inelastic tissue, and elastin, the elastic connective tissue. As a result, many normal mammals maintain a 'youthful' appearance with little gross anatomical change from age of maturity (i.e, first estrus) to more than 20 times age of maturity. In stark contrast, the extremely small ascorbic acid intake of humans does not enable them to maintain a youthful flexibility and elasticity beyond possibly 6 times age of maturity (most have died before 8 times). This loss of youthful qualities in structural proteins results in susceptibility for many forms of deterioration in both appearance and properties of vascular and other structural tissues. One such deterioration is aortic aneurysm, a common cause of morbidity and mortality. We hypothesize herein that improved dietary intake of essential nutrients needed to enhance the renewal of all structural proteins can: (1). prevent this deterioration completely; and (2). cure even large aortic aneurysms without surgery.

Topics: Animals; Aortic Aneurysm; Ascorbic Acid; Collagen; Elastic Tissue; Elastin; Female; Humans; Longevity; Male; Models, Cardiovascular

The biochemical mechanisms by which hypertension accelerates atherosclerosis and increases the risk of aortic aneurysm rupture are poorly understood. This study evaluates the effects of hypertension on aortic trace element concentrations and antioxidant status in tissue removed from 26 normotensive (NT) and 20 hypertensive (HT) patients. Twenty-seven of 46 patients (59%) had aneurysmal (AA), and 19 of 46 (41%) had occlusive disease (OD). Aortic iron concentrations were markedly higher in both OD and AA tissue compared with controls. A similar trend was observed with copper concentrations, with the highest elevations observed in HT AA tissues. No significant differences were observed in zinc concentrations, except that HT AA aorta had significantly lower zinc levels than either OD or control tissue. Aortic ascorbic acid concentrations in diseased aorta were lower than those of controls, but independent of blood pressure. Copper-zinc-superoxide dismutase activity was similarly reduced, with the lowest activity observed in diseased aorta from HT patients. Only HT AA aorta had significantly higher manganese-superoxide dismutase activity than controls. The aortas of patients with AA had significantly lower amounts of elastin and greater elastase activity than either controls or those with OD. However, the differences were independent of blood pressure. Hypertensive patients with OD and AA had 31% more and 27% less aortic collagen, respectively, than their NT counterparts (P less than 0.05). These data suggest that the reduction in aortic collagen and elastin in HT patients with AA compared with their NT counterparts may explain the larger size of aneurysms and predispose to their eventual rupture. Furthermore, the diminished antioxidant status associated with HT predisposes to lipid peroxidation, which contributes to the acceleration of these processes. Our studies were conducted in patients with established aortic aneurysmal and occlusive disease. Whether these observations are pertinent to the pathogenesis of AA and OD remains unclear and merits further study.

Topics: Antioxidants; Aorta; Aortic Aneurysm; Arteriosclerosis; Ascorbic Acid; Blood Pressure; Collagen; Copper; Elastin; Humans; Hypertension; Iron; Lipid Peroxidation; Male; Superoxide Dismutase; Trace Elements; Zinc

Altered trace elements and ascorbic acid metabolism have been implicated in the pathogenesis of atherosclerotic cardiovascular disease. However, their role in the disease process, or the effect of atherosclerosis on their tissue levels within plaque, is poorly understood. The present study analyzes the concentrations of Fe, Cu, Zn, and Mn, and ascorbic acid and superoxide dismutase (SOD) activity in tissue samples from 29 patients with abdominal aortic aneurysms (AAA) and 14 patients with atherosclerotic occlusive disease (AOD). It was observed that the Fe and Mn concentrations in AAA and AOD tissue were higher than the levels in nondiseased control aorta, whereas Cu and Zn levels in AAA and AOD tissue were similar to the levels in controls. The Zn:Cu ratio was significantly lower in the AAA tissue in comparison to both AOD and control tissue. In addition, AAA and AOD tissue had low ascorbic acid levels and low Cu,Zn-SOD activity with Cu,Zn-SOD:Mn-SOD ratios of 0.27 and 0.19, respectively, compared to a ratio of 3.20 in control aorta. These data indicate that aorta affected by aneurysms and occlusive disease have altered trace element and ascorbic acid concentrations, as well as low Cu,Zn-SOD activity. Although these observations do not directly support the hypothesis that AAA is associated with aortic Cu deficiency they do suggest a role for oxygen radicals or increased lipid peroxidation in occlusive and aneurysmal disease of the aorta.

Topics: Adult; Aged; Aorta, Abdominal; Aortic Aneurysm; Arterial Occlusive Diseases; Ascorbic Acid; Humans; Middle Aged; Reference Values; Superoxide Dismutase; Trace Elements