Aging is associated with increases in carotid arterial stiffness and this process appears to be accelerated in older adults with diabetes. It is known that older adults with higher levels of physical activity (PA) tend to have lower arterial stiffness values compared to their more sedentary counterparts. Women typically experience an increase in arterial stiffness and cardiovascular events after menopause compared to older men. It is currently unknown whether a greater degree of physical activity modulates vascular aging in individuals with diabetes, and whether sex differences exist. This study examined arterial stiffness estimated from carotid artery ultrasound images and blood pressure data available from the Canadian Longitudinal Study on Aging (CLSA) baseline data set in participants with non-Type 1 diabetes. Arterial stiffness was expressed as carotid artery distensibility, a measure of local arterial stiffness and calculated as the relative change in arterial diameter for a given change in pressure. PA was assessed via the Physical Activity Scale for the Elderly (PASE), a brief and easily scored 12-item survey used to assess usual PA in adults 65 years and older. This study evaluated the association between known cardiovascular disease risk factors/markers and carotid artery distensibility and examined the influence of PA on arterial stiffness. The influence of age and sex, while controlling for known cardiovascular disease risk factors and markers was examined in individuals with non-Type 1 diabetes. There was no main effect of PASE score on arterial distensibility before (P = 0.143) and after (P = 0.998) adjusting for known cardiovascular risk factors and markers, and there were no interactions between PASE and sex, or PASE and age. There was a main effect of age on arterial distensibility in both models (P=<0.001) and there was a main effect of sex on arterial distensibility in the final adjusted model only (P=0.040). These findings suggest that PASE is not predictive of arterial distensibility in older adults with non-Type 1 diabetes, and these results do not differ by age or sex. Follow-up analysis, using longitudinal models is required to further assess the influence of PA on vascular aging. / Thesis / Master of Science (MSc) / It is well-known that aging is associated with increases in arterial stiffness, which is the progressive impairment of the ability of the arteries to respond to changes in blood pressure and flow. Increased arterial stiffness is associated with the development of cardiovascular disease and appears to be accelerated in females and individuals with diabetes. Physical activity has been highlighted as a potential moderator of age-induced arterial stiffening. Healthy and physically active older adults typically display reduced arterial stiffening compared to their more sedentary counterparts, but the extent to which physical activity attenuates vascular stiffening in older adults with diabetes is unclear. Our results, from a cohort of approximately 2000 older Canadians with non-Type 1 diabetes, show that self-report physical activity level does not appear to be associated with arterial stiffness in this population, and these results do not differ by sex. Follow-up analysis should be conducted to assess the impact of physical activity over time on arterial stiffness in this population.

<p> Hypertension and reduced arterial distensibility are independent risk factors for cardiovascular disease. Previous research has found that isometric training reduces resting blood pressure (RBP) (Wiley et al. 1992; Taylor et al. 2003) yet the mechanisms responsible remain elusive. Improved arterial distensibility may contribute to this reduction in RBP. The purpose of the present study was threefold: 1) to replicate the RBP lowering effect of isometric handgrip (IHG) exercise; 2) to compare IHG and isometric leg press (ILP) based in their RBP lowering effects; and 3) to determine if central or peripheral arterial distensibility improved with IHG or ILP. The population examined was people whom were medicated for hypertension.</p> <p> RBP, as assessed by brachial oscillometry, and arterial distensibility, as assessed by Doppler ultrasound and applanation tonometry in the carotid, brachial and femoral arteries, were measured pre training, after 4 weeks of training, and post training. Participants performed unilateral IHG exercise (n=10) or ILP exercise (n=9) 3 times/week for 8 weeks at 30% MVC or acted as a non-exercising control group (n=5).</p> <p> Results indicated that the present study was unable to reproduce the RBP reductions noted in previous studies using IHG exercise. Also, the ILP exercise group did not experience reductions in RBP. Finally, neither central nor peripheral arterial distensibility improved in the IHG or ILP group when compared to the control group.</p> <p> Although these findings are contrary to our hypotheses one must consider that the control group examined contained very few subjects. This may have limited our ability to detect statistically significant changes in RBP and arterial distensibility.</p> / Thesis / Master of Science (MSc)

Several research studies indicate the increasing problem obesity has become over the past few decades (Andersen 1999:41; Fox, 1999:56-60; Kuczmarshi et al., 1994:205-212). Obesity, after cigarette smoke, is the leading cause of death in the USA and a combination of diet factors and physical inactivity (two primary contributors of obesity) leads to an average of 300,000 deaths per year (McGinnis & Foege, 1993:2207-2212). Previously little information was available on the effect of obesity on the peripheral vascularization, and even less about the effect of obesity on arterial compliance (Raison et al., 1998:299-303). Research indicated a decrease in arterial compliance with an increase in body weight (Kumaran et al., 2002:7; Sutton-Tyrrell et al., 2001:431; Tounian et al., 2001:1400-1404; Stepniakowski & Egan, 1995:R567) however, contradictory research where no association between obesity and arterial compliance was indicated, has also been found (Singhal et al., 2002:1920; Mangoni et al., 1995:986). Mackey et al. (2002:16) also found that an increased aortic stiffness is positively associated with lowered physical activity levels. A lifestyle consisting of moderate physical activity, has a positive effect on the health, lowering of chronic illness risks, the prevention of cardiovascular diseases and the improvement of quality of lie in overweight and obese patients (Adams et al., 2003542; Ferreira et al., 2003:1670-1678; Macera, 2003:123; Mclnnis, 200396; Kolden et al., 2002:447). Moderate aerobic exercise is also seen as a potential non-pharmaceutical therapeutic method to increase age associated decrease in arterial compliance in young, middle aged and older adults (Gates et al., 2003:2213; Havlik et al., 2003:156; Seals, 2003:68; Moreau et al., 2003:865; Joyner, 2000:1214; Cameron et al., 1999:653). The objective of this study was firstly to determine the correlation between obesity and vascular function in Caucasian women between the ages 19 and 56 and to determine which marker of obesity is the best predictor of a weakened vascular function (see article one). The second objective was to determine the correlation between physical activity, obesity and arterial compliance in Caucasian women between the ages 19 and 56 years (see article 2). A total of 115 Caucasian women were recruited to participate in this study. Anthropometric measurements and a comprehensive body composition profile was taken using the BOD POD. The Finometer apparatus was used to measure the arterial compliance and the sphygmomanometer to measure the subjects blood pressure. The subjects completed the Yale Physical Activity Survey questionnaire to determine their physical activity index. This study seems to indicate a positive relationship between arterial compliance and obesity which could be explained by the influence blood volume had in determining arterial compliance. A negative correlation was found between obesity and blood pressure where an increase in obesity caused an increase in both systolic and diastolic blood pressure. A positive correlation was found between physical activity and obesity. The higher the activity levels were in this study, the less obese the subjects tended to be. No correlation was found between physical activity and arterial compliance. A clear trend, even though no statistically significant differences, was found between physical activity and blood pressure. The more active the subjects were, the lower their blood pressure tended to be. / Thesis (M.Sc. (Human Movement Science))--North-West University, Potchefstroom Campus, 2005

Several research studies indicate the increasing problem obesity has become over the past few decades (Andersen 1999:41; Fox, 1999:56-60; Kuczmarshi et al., 1994:205-212). Obesity, after cigarette smoke, is the leading cause of death in the USA and a combination of diet factors and physical inactivity (two primary contributors of obesity) leads to an average of 300,000 deaths per year (McGinnis & Foege, 1993:2207-2212). Previously little information was available on the effect of obesity on the peripheral vascularization, and even less about the effect of obesity on arterial compliance (Raison et al., 1998:299-303). Research indicated a decrease in arterial compliance with an increase in body weight (Kumaran et al., 2002:7; Sutton-Tyrrell et al., 2001:431; Tounian et al., 2001:1400-1404; Stepniakowski & Egan, 1995:R567) however, contradictory research where no association between obesity and arterial compliance was indicated, has also been found (Singhal et al., 2002:1920; Mangoni et al., 1995:986). Mackey et al. (2002:16) also found that an increased aortic stiffness is positively associated with lowered physical activity levels. A lifestyle consisting of moderate physical activity, has a positive effect on the health, lowering of chronic illness risks, the prevention of cardiovascular diseases and the improvement of quality of lie in overweight and obese patients (Adams et al., 2003542; Ferreira et al., 2003:1670-1678; Macera, 2003:123; Mclnnis, 200396; Kolden et al., 2002:447). Moderate aerobic exercise is also seen as a potential non-pharmaceutical therapeutic method to increase age associated decrease in arterial compliance in young, middle aged and older adults (Gates et al., 2003:2213; Havlik et al., 2003:156; Seals, 2003:68; Moreau et al., 2003:865; Joyner, 2000:1214; Cameron et al., 1999:653). The objective of this study was firstly to determine the correlation between obesity and vascular function in Caucasian women between the ages 19 and 56 and to determine which marker of obesity is the best predictor of a weakened vascular function (see article one). The second objective was to determine the correlation between physical activity, obesity and arterial compliance in Caucasian women between the ages 19 and 56 years (see article 2). A total of 115 Caucasian women were recruited to participate in this study. Anthropometric measurements and a comprehensive body composition profile was taken using the BOD POD. The Finometer apparatus was used to measure the arterial compliance and the sphygmomanometer to measure the subjects blood pressure. The subjects completed the Yale Physical Activity Survey questionnaire to determine their physical activity index. This study seems to indicate a positive relationship between arterial compliance and obesity which could be explained by the influence blood volume had in determining arterial compliance. A negative correlation was found between obesity and blood pressure where an increase in obesity caused an increase in both systolic and diastolic blood pressure. A positive correlation was found between physical activity and obesity. The higher the activity levels were in this study, the less obese the subjects tended to be. No correlation was found between physical activity and arterial compliance. A clear trend, even though no statistically significant differences, was found between physical activity and blood pressure. The more active the subjects were, the lower their blood pressure tended to be. / Thesis (M.Sc. (Human Movement Science))--North-West University, Potchefstroom Campus, 2005

Les fibres élastiques, constituées essentiellement d'élastine (90%), procurent aux vaisseaux sanguins leurs propriétés d'élasticité et de résilience. L'élastine est synthétisée a partir d'un précurseur –la tropoélastine- seulement depuis la grossesse jusqu'à la fin de la puberté. Au cours du vieillissement physiologique, l'augmentation de l'expression des enzymes élastolytiques, la calcification aortique ainsi que la glycation des protéines constituent les principaux mécanismes biologiques de la dégradation du stock non-renouvelable des fibres élastiques et, par conséquence, de la rigidité artérielle. Dans ce travail de thèse, nous avons étudié l'impact du traitement chronique (3 mois) par le minoxidil (120 mg/L) ou par un extrait de graines d'aneth (5% ou 10 % v/v) -dans l'eau de boisson- sur la production d'élastine in vivo et sur le fonctionnement et la structure des artères élastiques (aorte abdominale ou ascendante) des souris adultes (6 mois) et âgées (24 mois) des deux sexes. Le traitement par l'extrait d'aneth a ré-induit la synthèse des fibres élastiques chez les souris adultes et âgées, alors que, chez les souris traitées par le minoxidil, nous avons observé l'apparition de ces néo-fibres seulement chez les souris âgées. D'autre part, les deux traitements ont préservé l'intégrité des lames élastiques en diminuant nettement leur taux de ruptures lié à l'âge. Le dosage des protéines de la matrice extracellulaire a révélé que le traitement par l'extrait d'aneth ou par le minoxidil augmente la quantité de desmosine (élastine) dans la paroi artérielle des souris femelles, alors que, chez les souris males, seulement l'extrait d'aneth a induit une faible augmentation de cette protéine. L'étude biomécanique de l'aorte a montré que les deux traitements améliorent significativement la distensibilité de l'aorte, surtout chez les souris femelles. En outre, le traitement par l'extrait d'aneth a réversé l'hypertrophie cardiaque lié à l'âge seulement chez les souris males âgées. Nos résultats montrent que l'extrait d'aneth et le minoxidil possèdent des potentialités anti-vieillissement cardiovasculaire chez la souris. Ces deux produits pourraient faire l'objet des études cliniques ultérieures pour confirmer leurs effets chez l'Homme. / Elastic fibers, primarily composed of elastin (90%), endow the blood vessels with the mechanical properties of elasticity and resilience, which are essential to their function. Elastin is synthesized as a precursor, tropoelastin, only from the late stages of gestation until late childhood. During physiological aging, increased elastolytic activity, aortic calcification and protein glycation are the main mechanisms of elastic fibers degradation and, thereafter, arterial rigidity. In this work, we investigated the impact of chronic treatment (3 months) with dill extract (5% or 10% v/v) or with minoxidil (120 mg/L) -in drinking water- on elastin production in vivo and structure and function of elastic arteries (abdominal and ascending aorta) of adult (6-month-old) and aged (24-month-old) male and female mice. Treatment with dill extract re-induced the elastic fiber formation in both adult and aged mice. However, treatment with minoxidil induced elastic fiber formation in aged mice only. Both treatments preserved elastic lamella integrity by reducing their age-related disruptions. Extracellular matrix protein quantification revealed that chronic treatment with dill extract or minoxidil increase desmosine (elastin) levels in the arterial wall of female mice, whereas in male mice, only dill extract slightly increases the desmosine level. Regarding the blood vessel biomechanics, both treatments enhanced aortic distensibility, especially in female mice. Moreover, treatment with dill extract reversed the age-related cardiac hypertrophy only in male mice. Our results suggest that dill extract and minoxidil have potential anti-aging effects on the cardiovascular system. Both products may be of interest to subsequent clinical trials to confirm their effects in human beings.