Oestrogen and vascular disease

Neonatal glucocorticoid overexposure alters cardiovascular function in young adult horses in a sex-linked manner

Prenatal glucocorticoid overexposure has been shown to programme adult cardiovascular function in a range of species, but much less is known about the long-term effects of neonatal glucocorticoid overexposure. In horses, prenatal maturation of the hypothalamus-pituitary-adrenal axis and the normal prepartum surge in fetal cortisol occur late in gestation compared to other precocious species. Cortisol levels continue to rise in the hours after birth of full-term foals and increase further in the subsequent days in premature, dysmature and maladapted foals. Thus, this study examined the adult cardiovascular consequences of neonatal cortisol overexposure induced by adrenocorticotropic hormone administration to full-term male and female pony foals. After catheterisation at 2-3 years of age, basal arterial blood pressures (BP) and heart rate were measured together with the responses to phenylephrine (PE) and sodium nitroprusside (SNP). These data were used to assess cardiac baroreflex sensitivity. Neonatal cortisol overexposure reduced both the pressor and bradycardic responses to PE in the young adult males, but not females. It also enhanced the initial hypotensive response to SNP, slowed recovery of BP after infusion and reduced the gain of the cardiac baroreflex in the females, but not males. Basal diastolic pressure and cardiac baroreflex sensitivity also differed with sex, irrespective of neonatal treatment. The results show that there is a window of susceptibility for glucocorticoid programming during the immediate neonatal period that alters cardiovascular function in young adult horses in a sex-linked manner.

Interactive relation of insulin and gender to cardiovascular reactivity in healthy young adults

High levels of insulin may promote hypertension pathogenesis, in part, via enhanced sympathetic nervous system (SNS) activity. This study examined potential interactive relations of fasting insulin levels, gender, and race to cardiovascular reactivity-a correlate of SNS activation. Hemodynamic responses to 4 laboratory challenges were determined by impedance cardiography in 64 healthy young adults (ages 18-26; 48% male; 50% White, 50% African American). Also examined were lipoprotein lipids, central and total adiposity, self-reported dietary factors, and physical activity. High-insulin (>10.2 mU/ml) men showed greater total peripheral resistance and longer pre-ejection period responses than low-insulin ( pound 10.2 mU/ml) men. High-insulin women displayed greater cardiac index responses than high-insulin men. High insulin levels were related to greater percentage body fat, dietary carbohydrate and fat intake, lower high-density lipoprotein (HDL) cholesterol (in men), higher total cholesterol (in women), and a trend toward higher triglycerides. Cardiovascular reactivity findings were unchanged after statistical adjustment for total and HDL cholesterol, triglycerides, percentage body fat, dietary carbohydrates, and fat. The Gender x Insulin (continuous scores) interaction accounted for 7% and 9% of the variance in cardiac index and total peripheral resistance responses, respectively. These results indicate that high insulin levels are associated with greater vascular reactivity in young men and cardiac reactivity in young women. Enhanced cardiovascular reactivity may constitute a biobehavioral dimension of the metabolic syndrome.

Sex-related differences in outcome after vascular interventions for lower limb ischemia

OBJECTIVE

The purpose of this study was to investigate sex-related differences in outcome, defined as amputation rate and survival in patients treated for lower limb ischemia.

MATERIAL AND METHOD

Age, sex, and type of procedure for all patients undergoing vascular interventions for lower limb ischemia in Stockholm, Sweden, from 1970 to 1994, were obtained from the National Board of Health and Welfare. All patients who underwent amputation after treatment were analyzed separately. Data on deceased patients were extracted from the cause-of-death register.

RESULTS

Women had lower survival rates than men at 30 days and 1 and 5 years after operation (89% vs 92%, 75% vs 80%, and 50% vs 55%; P <.001). In the multivariate analysis of risk factors for death during the whole study period, increasing age, calendar year (1980 to 1989), and male sex were significant risk factors (P <.001). The percentage of women who underwent amputation after treatment was comparable with the percentage of men who underwent amputation (11.4% vs 10.2%, P =.075). The multivariate analysis identified increased age and calendar year (1985 to 1994) as important risk factors for amputation (P <.001). Female sex was not found to increase the risk for amputation. Patients who underwent amputation were older than patients with intact limbs (73 vs 68 years, P <.001). The highest percentage of patients who underwent amputation was found among those treated with femorodistal bypass (20%, P =.001).

CONCLUSIONS

Female sex is not an important risk factor for poor outcome after treatment for lower limb ischemia, when their increased age has been accounted for. These results imply that we should continue to consider age and type of procedure when estimating outcome, and women should not be refused an intervention on a sex-related basis. We should possibly be more selective toward men considering their higher mortality rates.