Clonidine Prevents Insulin Resistance and Hypertension in Obese Dogs

Rocchini, Albert P.; Mao, Hui Z.; Babu, Keshava; Marker, Paul H.; Rocchini, Albert J.

doi:10.1161/01.hyp.33.1.548

Cited by 89 publications

(70 citation statements)

References 30 publications

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“…11,29 Studies in animal models have also highlighted the impact of excess weight gain in hypertension by providing mechanistic insights. 3,30 Abnormal renal sodium and water reabsorption and impaired pressure natriuresis appear to play a major role in obesity-related hypertension. 31 To maintain sodium balance, obese subjects present increased arterial pressure.…”

Section: Discussionmentioning

confidence: 99%

Impact of Obesity on 24-Hour Ambulatory Blood Pressure and Hypertension

et al. 2005

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Abstract-The purpose of the present study was to determine the relationship between body mass index (BMI) and parameters derived from 24-hour ambulatory blood pressure monitoring including mean 24-hour daytime and nighttime systolic and diastolic blood pressures, 24-hour daytime and nighttime pulse pressure, mean 24-hour daytime and nighttime heart rate, dipping and nondipping status. 3216 outpatient subjects who visited our hypertension center and were never treated with antihypertensive medication underwent 24-hour blood pressure monitoring. BMI was significantly correlated with clinic systolic and diastolic blood pressures. Significant correlations were also found between BMI and mean 24-hour daytime and nighttime systolic blood pressure, 24-hour daytime and nighttime pulse pressure, and mean 24-hour daytime and nighttime heart rate. In multivariate regression analysis, clinic systolic, diastolic blood pressure, mean 24-hour systolic blood pressure, 24-hour pulse pressure, and high-density lipoprotein were independently correlated with BMI. The incidence of white coat hypertension was higher in overweight and obese patients than in normal weight subjects. Confirmed ambulatory blood pressure hypertension was also found to be higher in overweight and obese individuals compared with normal weight subjects. Our data also highlight the higher incidence of nondipping status in obesity. These findings suggest that obese patients had increased ambulatory blood pressure parameters and altered circadian blood pressure rhythm with increased prevalence of nondipping status. Key Words: blood pressure monitoring, ambulatory Ⅲ body mass index Ⅲ hypertension Ⅲ obesity T he increasing prevalence of obesity in industrialized countries is an alarming epidemic. Epidemiological studies clearly demonstrate a correlation between body weight and blood pressure in obese populations. In the Framingham Study, 70% of the new cases of essential hypertension were related to excess body fat. 1 Population studies have shown that office blood pressure closely correlates with body mass index (BMI) and other anthropometric indices of obesity such as waist-to-hip ratio. 2 Experimental studies in animals have also shown that excess weight gain caused by a chronic high-fat diet almost invariably raises blood pressure. [3][4][5] Considerable evidence suggests that excess weight gain is related to human essential hypertension. Currently, 30% to 35% of adults in the United States are obese, and Ͼ30% are overweight. 6 -10 In some groups, such as black women older than age 50, the prevalence of obesity may be as high as 70% to 80%, coinciding with a rate of hypertension of Ͼ70%. 11 Initially reserved for research purposes, ambulatory blood pressure monitoring has gradually become a widely used clinical tool for diagnostic purposes and for assessment of treatment efficacy. Evidence is available that 24-hour day or nighttime average blood pressure values correlate with subclinical organ damage more closely than office values. 12 Evidence is also availa...

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Section: Discussionmentioning

confidence: 99%

Impact of Obesity on 24-Hour Ambulatory Blood Pressure and Hypertension

et al. 2005

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“…Activation of the sympathetic nervous system, which is associated with abdominal adiposity and hyperinsulinaemia, could modulate renal tubular sodium handling [33,34,35].…”

Section: Discussionmentioning

confidence: 99%

Metabolic syndrome and renal sodium handling in three ethnic groups living in England

et al. 2004

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Aim/hypothesis. Increased proximal renal sodium reabsorption is associated with central adiposity and insulin resistance in white men. Our study examined whether this association also exists in other ethnic groups with different prevalences of insulin resistance and associated metabolic abnormalities. Methods. We studied the association between fractional renal excretion of endogenous lithium (FELi) and metabolic syndrome in a population study of 1190 randomly selected men and women who where 40 to 59 years of age (426 white, 397 of African and 367 of South Asian origin). Anthropometric values, blood pressure, biochemical values, questionnaire data and timed urine collections were obtained with standardised techniques. Endogenous lithium in serum and urine was measured by absorption spectrophotometry. Metabolic markers were the homeostasis model assessment (HOMA) index, waist circumference, serum triglycerides, serum HDL cholesterol and metabolic syndrome as defined by Adult Treatment Panel III criteria.Results. In white men and women a higher rate of proximal sodium re-absorption was inversely associated with higher waist circumference, serum triglycerides and HOMA index, and with lower serum HDL cholesterol (all p≤0.001)

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“…Also, combined a-and ß-adrenergic blockade markedly attenuated the rise in blood pressure that occurred in dogs fed a high fat diet for 5 weeks. Clonidine, a drug that stimulates central a-2 receptors and reduces sympathetic activity, also markedly blunted the rise in blood pressure in dogs fed a high fat diet (28). Finally, combined a-and ß-adrenergic blockade for one month reduced blood pressure more in obese compared to lean essential hypertensive patients (29).…”

Section: Sympathetic Activation Contributes To Hypertension In Obese mentioning

confidence: 95%

Role of sympathetic nervous system and neuropeptides in obesity hypertension

Hall

Brands

Hildebrandt

et al. 2000

Braz J Med Biol Res

125

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Obesity is the most common cause of human essential hypertension in most industrialized countries. Although the precise mechanisms of obesity hypertension are not fully understood, considerable evidence suggests that excess renal sodium reabsorption and a hypertensive shift of pressure natriuresis play a major role. Sympathetic activation appears to mediate at least part of the obesity-induced sodium retention and hypertension since adrenergic blockade or renal denervation markedly attenuates these changes. Recent observations suggest that leptin and its multiple interactions with neuropeptides in the hypothalamus may link excess weight gain with increased sympathetic activity. Leptin is produced mainly in adipocytes and is believed to regulate energy balance by acting on the hypothalamus to reduce food intake and to increase energy expenditure via sympathetic activation. Short-term administration of leptin into the cerebral ventricles increases renal sympathetic activity, and long-term leptin infusion at rates that mimic plasma concentrations found in obesity raises arterial pressure and heart rate via adrenergic activation in nonobese rodents. Transgenic mice overexpressing leptin also develop hypertension. Acute studies suggest that the renal sympathetic effects of leptin may depend on interactions with other neurochemical pathways in the hypothalamus, including the melanocortin-4 receptor (MC4-R). However, the role of this pathway in mediating the long-term effects of leptin on blood pressure is unclear. Also, it is uncertain whether there is resistance to the chronic renal sympathetic and blood pressure effects of leptin in obese subjects. In addition, leptin also has other cardiovascular and renal actions, such as stimulation of nitric oxide formation and improvement of insulin sensitivity, which may tend to reduce blood pressure in some conditions. Although the role of these mechanisms in human obesity has not been elucidated, this remains a fruitful area for further investigation, especially in view of the current epidemic of obesity in most industrialized countries. Correspondence

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Clonidine Prevents Insulin Resistance and Hypertension in Obese Dogs

Cited by 89 publications

References 30 publications

Impact of Obesity on 24-Hour Ambulatory Blood Pressure and Hypertension

Impact of Obesity on 24-Hour Ambulatory Blood Pressure and Hypertension

Metabolic syndrome and renal sodium handling in three ethnic groups living in England

Role of sympathetic nervous system and neuropeptides in obesity hypertension

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