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Query: UMLS:C0085580 (essential hypertension)
 14,686 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To identify characteristics that may contribute to salt sensitivity, we conducted studies of normal subjects who are at risk for hypertension, namely blacks, subjects older than 40 years of age, and first-degree relatives of subjects with essential hypertension. We also formulated definitions for salt sensitivity and resistance with a short-term volume expansion and contraction protocol and additionally from data derived from studies of long-term reduced dietary salt intake. We examined the effects of augmented potassium and calcium intake and also those of sodium as the chloride or the bicarbonate salt. Finally, we sought genetic markers that are associated with salt sensitivity. We found that salt sensitivity is a function of age and is more common in blacks than whites. These groups also have relatively delayed acute salt excretion compared with controls. We were unable to identify effects of gender. Haptoglobin phenotypes (HP 1-1) may facilitate identification of salt-sensitive individuals. A high potassium intake may make individuals less salt sensitive. Sodium chloride and sodium bicarbonate differ in their effects on blood pressure. Sodium chloride augments urinary calcium excretion, but sodium bicarbonate does not. Differences between susceptible and nonsusceptible groups, together with improved knowledge of electrolyte interactions, may facilitate our understanding of salt-sensitive hypertension.
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PMID:Salt sensitivity and resistance of blood pressure. Age and race as factors in physiological responses. 184 22

To investigate the mechanism whereby blood pressure rises with NaCl loading in salt-sensitive essential hypertension, salt-sensitivity index was determined along with sodium and lithium clearances, plasma Na+,K(+)-ATPase inhibitor and intra-erythrocyte sodium and potassium concentrations. Salt-sensitivity index was defined as the percentage of change in mean blood pressure when NaCl intake was changed from low (34 mmol/day) to high (342 mmol/day). Salt-sensitivity index was inversely correlated with fractional excretion of lithium both on the low and high NaCl diets (r = -0.721, P less than 0.01 and r = -0.591, P less than 0.02, respectively; n = 16), but not with fractional excretion of sodium. The change of plasma Na+,K(+)-ATPase inhibition with NaCl loading had a direct correlation with salt-sensitivity index (r = 0.704, P less than 0.01; n = 16). Either intra-erythrocyte sodium and potassium concentrations or the ratio of these two values did not change significantly with an increase of dietary NaCl intake. These results suggest that an enhancement of proximal tubular sodium reabsorption stimulates secretion of plasma Na+,K(+)-ATPase inhibitor which may be involved in a rise in blood pressure with sodium loading. They also suggest that lithium clearance is a determinant which can predict salt sensitivity without actual NaCl loading.
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PMID:Renal sodium handling and sodium transport inhibitor in salt-sensitive essential hypertension. 184 59

Evidence has accumulated over the past decade that suggests a relationship between low calcium intake, abnormalities in cation metabolism and hypertension in certain segments of the essential hypertension population. This evidence has been developed from epidemiological data, calcium intervention trials and observations related to biochemical alterations suggestive of a calcium deficiency in certain patients with hypertension and in animal models of essential hypertension. It is becoming increasingly evident that salt sensitive individuals are especially likely to be characterized by abnormalities of calcium metabolism and blood pressure responses to dietary calcium. In this review the role of calcium in the regulation of blood pressure is examined with an emphasis on epidemiological, biochemical, hemodynamic and dietary intervention data in the salt sensitive hypertensive patient.
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PMID:Calcium metabolism and dietary calcium in salt sensitive hypertension. 187 9

In this review, the relationship between hypertension and abnormal carbohydrate metabolism is explored. A review of the current literature reveals that people with hypertension are also likely to suffer from insulin resistance, glucose intolerance, and hyperinsulinemia. Likewise, hypertension is prevalent in obese and diabetic patients. Deficiency of insulin at the cellular level may be a common mechanism in the development of hypertension in patients with type I or type II diabetes mellitus. Essential hypertension appears to be an insulin-resistant state. Insulin resistance may engender hypertension by increasing peripheral vascular resistance as well as by increasing salt retention at the level of the kidney. Therefore effective antihypertensive therapy should include agents that do not adversely affect carbohydrate metabolic abnormalities. Commonly used antihypertensive agents, such as thiazide, thiazide-like diuretics, and beta-blockers, are associated with glucose intolerance and increased insulin resistance. In contrast, angiotensin-converting enzyme inhibitors, calcium antagonists, and peripheral alpha-blockers (such as prazosin and terazosin) do not adversely affect glucose tolerance or insulin sensitivity. In addition, alpha-blockers have a positive effect on the serum lipid profile. The entire multifactorial cardiac risk profile must be considered when choosing therapeutic agents for conditions that have an impact on cardiovascular disease.
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PMID:Is hypertension an insulin-resistant state? Metabolic changes associated with hypertension and antihypertensive therapy. 187 73

The effects of a two-week high sodium diet on mitral flow pattern were assessed in 29 patients with essential hypertension (81.9 +/- 6.9 years). Transmitral flow was recorded during different rates of salt intake; 7 g/day for 8 weeks and 20 g/day for 2 weeks. With sodium loading, 25 patients whose mean blood pressure (MBP) increased by 10 percent or more were termed salt-sensitive (SS) group, and 4 patients whose MBP did not change or increased by less than 10 percent were termed non-salt-sensitive (NSS) group with mitral flow velocity integral, cardiac output (CO) and total peripheral resistance (TPR) were calculated. Thirteen of the SS patients were defined as "SST" in which an increase in TPR was greater than that in CO with sodium repletion. In the remaining 12 SS patients termed "SSc", the increase in CO was greater than that in TPR with salt loading. CO increased significantly in the SSc patients, but did not change in the SST or NSS group with sodium loading. TPR increased significantly in the SST and NSS subjects, and decreased significantly in the SSc patients. Peak velocity of transmitral flow in the rapid filling phase (R) decreased significantly in the SST and NSS patients, and increased significantly in the SSc group. On the other hand peak velocity of transmitral flow in the atrial contraction phase (A) increased significantly in the SST and SSc groups, but remained unchanged in the NSS patients. There was a significant increase in A/R in the SSt group and a significant decrease in A/R in the SSc patients with sodium loading.
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PMID:[Mitral flow responses to two-week salt loading in elderly hypertensive patients]. 189 33

The pathogenesis of essential hypertension (EH) is reviewed with a special focus on the development phase or the pre-hypertensive period. Three animal models are presented: the spontaneously hypertensive rat, the Dahl's salt-sensitive rat, and the Milan hypertensive rat. Some of the findings in animal models have inspired new fields and technical approaches for studying EH in man. From the original idea of Page, a new mosaic of various etiological parameters serves as a basis for reviewing the multiple facets of EH in man. One must conclude that EH is heterogeneous disease and most likely every single hypertensive patient belongs to a subgroup of the whole population of hypertensives.
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PMID:Pathogenesis of the essential hypertensions. 191 Nov 13

We studied the renal function of cations excretion in 86 normal children, aged 4-6 years old. 24-hour urinary excretion of sodium, potassium, calcium, magnesium, copper and zinc were measured before and after acute oral salt loading. The result showed that urinary sodium levels were significantly lower (101.88 mmol/24 h, 126.58 mmol/24 h, respectively, P less than 0.01) in children with family history of essential hypertension than in those without family history after salt loading. This suggests that the children with family history may have hereditary functional defect in the excretion of sodium before developing hypertension. We also found the renal excretions of potassium, calcium and zinc showed difference between children with and without family history of essential hypertension.
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PMID:[Renal function of cations excretion in children predisposed to essential hypertension]. 191 79

There is much circumstancial and some direct evidence in humans to suggest that a high consumption of salt predisposes communities and individuals to the development of essential hypertension. Restriction of salt intake in the diet lowers blood pressure in many subjects with high blood pressure and this fall in blood pressure is mediated in part by a diminished renin response to sodium restriction as hypertension develops. The effect of sodium restriction, like diuretics, is additive to many blood pressure lowering drugs, particularly those that inhibit the renin system such as beta-blockers and angiotensin converting enzyme inhibitors.
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PMID:Dietary salt intake and hypertension. 192 Dec 46

Metabolic acidosis has recently been observed in rat models of salt-sensitive genetic hypertension. Studies in normotensive salt-sensitive men have likewise demonstrated slightly but significantly lower arterial pH and bicarbonate levels, relating salt-sensitivity to the presence of a relative acidosis in man. The administration of alkalinizing sodium salts such as sodium bicarbonate or citrate have been shown to have no effect on or to even lower blood pressure in patients with essential hypertension. Possible factors contributing to the perturbation in acid-base status include an enhanced Na+/H(+)-antiport activity, lower intracellular pH levels and altered renal electrolyte handling as found in rat models of hypertension and in patients with essential hypertension.
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PMID:Abnormal acid-base regulation in salt-sensitive normotensive man. 192 Dec 51

The role of dietary sodium in the pathogenesis of essential hypertension has stimulated a great deal of interest and investigation in recent years. There are epidemiologic studies in the literature that suggest a link between dietary sodium intake and the prevalence of hypertension. However, not all patients are prone to the development of hypertension in response to dietary sodium. Therefore, a distinction between salt sensitivity and salt-resistant essential hypertension has evolved from this observation. The mechanisms which related dietary sodium to the pathogenesis of essential hypertension are not clearly defined, although it appears that inborn errors of renal sodium handling, along with certain components of the sympathetic nervous system, may be involved. Furthermore, intracellular sodium and its transport mechanisms have been implicated in the pathogenesis of hypertension associated with dietary sodium. Finally, there appears to be a correlation between dietary sodium, salt sensitivity, and the progression of renal disease. That is to say, patients with salt-sensitive essential hypertension appear to demonstrate a more relentless course to end-stage renal disease. This tendency may be related to deranged hemodynamic adaptation of the renal circulation in response to dietary sodium intake and the resulting rise in systemic blood pressure. The mechanism for this derangement of renal hemodynamic adaptation in salt-sensitive hypertensives remains to be determined.
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PMID:Salt sensitivity in hypertension: implications for the kidney. 193 44


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