Can atherosclerosis regress? The role of the vascular extracellular matrix and the age-related changes of arteries

Accelerated Vascular Aging as a Paradigm for Hypertensive Vascular Disease: Prevention and Therapy

Aging is considered the most important nonmodifiable risk factor for cardiovascular disease and death after age 28 years. Because of demographic changes the world population is expected to increase to 9 billion by the year 2050 and up to 12 billion by 2100, with several-fold increases among those 65 years of age and older. Healthy aging and prevention of aging-related diseases and associated health costs have become part of political agendas of governments around the world. Atherosclerotic vascular burden increases with age; accordingly, patients with progeria (premature aging) syndromes die from myocardial infarctions or stroke as teenagers or young adults. The incidence and prevalence of arterial hypertension also increases with age. Arterial hypertension-like diabetes and chronic renal failure-shares numerous pathologies and underlying mechanisms with the vascular aging process. In this article, we review how arterial hypertension resembles premature vascular aging, including the mechanisms by which arterial hypertension (as well as other risk factors such as diabetes mellitus, dyslipidemia, or chronic renal failure) accelerates the vascular aging process. We will also address the importance of cardiovascular risk factor control-including antihypertensive therapy-as a powerful intervention to interfere with premature vascular aging to reduce the age-associated prevalence of diseases such as myocardial infarction, heart failure, hypertensive nephropathy, and vascular dementia due to cerebrovascular disease. Finally, we will discuss the implementation of endothelial therapy, which aims at active patient participation to improve primary and secondary prevention of cardiovascular disease.

Matrix metalloproteinases and atherogenesis in dependence of age

BACKGROUND

Changes in the proteoglycan metabolism of the intima of arteries belong to the initial lesions of atherosclerosis (AS). The accumulation of proteoglycans, alterations of pericellular glycoproteins and modulations of collagen turnover also play a fundamental role in the progression of AS. They influence lipid retention, cell behavior and calcinosis. The decisive role played by the matrix metalloproteinases (MMPs) and their inhibiting factors (tissue inhibitors of metalloproteinases [TIMPs]) in these processes is not yet fully understood and therefore the subject of this overview. The causes of the abrupt change of a long-term existing stabile AS to a vulnerable plaque as well as the participation of age-related vascular wall remodeling in the progression of AS also remain open questions.

DISCUSSION

Apart from the well-known risk factors for AS, less well-known influences like the disturbances of gene expression in vascular smooth muscle cells affect an MMP/TIMP imbalance. The various consequences of this imbalance range from intima cell proliferation as an early change in AS as well as accelerated progression to the destabilization of fibrous plaques by increased collagenolysis as well as the formation of aneurysms. Infectious or toxic influences may trigger these mechanisms; an involvement of age-related vessel wall changes should also be considered. The prognostic significance of circulating MMP concentrations for the existence of instabile plaques are of great interest, as is the plaque stabilizing effect of statins by suppression of MMPs.

CONCLUSIONS

MMPs navigate the behavior of vascular wall cells in different AS stages, in adaptive remodeling, in normal aging and in non-atherosclerotic vessel disease. The clinical relevance of a disturbance in the MMP/TIMP balance is demonstrated firstly by the initiation of AS due to migration and proliferation of intima cells and secondly in the collagenolysis, necrotic transformation and apoptosis of existing fibrous lesions resulting in instabile rupture proned plaques. Investigations into the genetic typing of MMPs and the results of experimental gene deficiency models have significantly contributed to the clarification of these facts.

Do cigarette smokers with erectile dysfunction benefit from stopping?: a prospective study

OBJECTIVE

To assess whether stopping smoking can improve erectile dysfunction (ED) in smokers, as cigarette smoking is a known risk factor for ED.

PATIENTS AND METHODS

Smokers who requested nicotine replacement therapy (NRT) and complained of ED were first evaluated for hypertension, dyslipidaemia, diabetes, psychiatric disorders and drug history. The grade of ED in smokers with none of these risk factors was then determined using the five-item version of the International Index of Erectile Function (IIEF-5) before NRT, and the grading repeated after 1 year of follow-up. The correlation between the exposure to smoking (pack-years) and severity of ED was assessed before the follow-up. The ED status between patients who stopped smoking after NRT and those who continued during the follow-up was then compared before and after the follow-up.

RESULTS

The severity of ED correlated significantly with the level of exposure to smoking. Age and ED status before the follow-up were not significantly different between 118 patients who stopped (ex-smokers) and 163 who continued smoking (current smokers). After 1 year the ED status improved in > or = 25% of ex-smokers but in none of the current smokers; 2.5% of ex-smokers and 6.8% of current smokers had a deterioration in ED. Ex-smokers had a significantly better ED status after the follow-up (P = 0.009). Among ex-smokers, patients with advanced ED and those who were older had less improvement.

CONCLUSION

There is a strong association between the intensity of cigarette smoking and degree of ED. Stopping cigarette smoking can improve ED in a considerable proportion of smokers. Age and the severity of ED before stopping are inversely related to the chance of improvement.