Venous Changes in Renal Hypertensive Rats: The Role of Humoral Factors

Simon, Géza

doi:10.1159/000158176

Cited by 7 publications

(7 citation statements)

References 10 publications

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“…This study, although in part confirmatory of previous in vivo experiments, 5 used in vitro techniques, therefore, its findings have to be interpreted with caution. Several studies have indicated that isolated vascular smooth muscle cells in culture must first "dedifferentiate" to morphologically resemble fibroblasts before proliferation will occur.…”

Section: Discussionsupporting

confidence: 73%

Angiopathic serum factor in perinephritic hypertensive dogs.

Simon¹

1979

Hypertension

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SUMMARY To investigate the role of circulating humoral substances in the patbogenesis of increased vascular wall water and sodium concentration in experimental hypertension, rabbit aortic media explants were cultured in tissue culture medium supplemented (10-20%) with serum obtained from the same dogs (n = 7): \) before the induction of hypertension; 2) after wrapping one kidney in silk (two-kidney perinephritic hypertension, 2-KPHT); and 3) after contralateral nephrectomy (1-KPHT). Cultures also were run with serum of sham-wrapped and then unilaterally nephrectomized nonnotenshe dogs (n = 4). After 3 weeks of culture, the explants were harvested, and their water, sodium and potassium concentration was measured. Compared to the composition of explants cultured in prehypertensive serum, the water concentration of explants cultured in 1-KPHT and the sodium concentration of explants cultured in 2-KPHT and 1-KPHT serum were increased concentration in experimental and human hypertension has been known for many years 1 and has been generally ascribed to the effects of increased intraluminal pressure.2 Recent reports of similar changes in the veins of experimental animals with hypertension raised the possibility that humoral or neural stimuli may also play a role in the pathogenesis of abnormal vascular wall composition in hypertension.8 ' * Evidence for the role of humoral factors was found in parabiotic rats, one of which was made hypertensive by partial constriction of one renal artery.6 There were similar increases in the water and electrolyte content of the vena cavae of hypertensive rats and their normotensive parabiotic mates. From these experiments it could not be determined whether the unknown humoral factor, originating from the hypertensive rat, affected venous wall metabolism directly or whether its action was mediated through other mechanisms. The purpose of the present experiments was to investigate the direct effect of serum from hypertensive dogs on the water and electrolyte composition of rabbit aortic media in culture. Methods Preparation of DogsMale mongrel dogs weighing 18-27 kg were trained to lie quietly during percutaneous femoral artery puncture for blood pressure measurements. A resting mean arterial pressure of less than 130 mm Hg was documented in each dog on at least one occasion. In seven dogs anesthetized with pentobarbital (30 mg/kg I.V.), one kidney was wrapped in silk to induce perinephritic hypertension. Two weeks later, the contralateral kidney was removed surgically. Four dogs underwent sham-wrapping of one kidney and then contralateral nephrectomy 2 weeks later. The operations were performed as described in a previous publication.6 Antibiotics were not used either pre-or postoperatively. Blood pressure measurements were repeated before nephrectomy and again 4 weeks after nephrectomy. During the entire study period the dogs were maintained on a diet of standard dog chow and water ad libitum.

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Section: Discussionsupporting

confidence: 73%

Angiopathic serum factor in perinephritic hypertensive dogs.

Simon¹

1979

Hypertension

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“…1,6,7 Older studies also implicate an unknown humoral mechanism that operates in some models of experimental hypertension. 8 The endothelium-derived peptide endothelin (ET)-1 is a potent venoconstrictor in most vascular beds. 9 Changes in endogenous ET-1 formation consistent with a role for the peptide in venomotor adjustments to volume stimuli have been measured in humans.…”

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confidence: 99%

Mechanisms of Increased Venous Smooth Muscle Tone in Desoxycorticosterone Acetate-Salt Hypertension

2000

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Abstract-The purpose of the present study was to identify mechanisms that contribute to increased venous smooth muscle tone in desoxycorticosterone acetate (DOCA)-salt hypertension in rats. Male Sprague-Dawley rats were uninephrectomized, received subcutaneous implants of DOCA, and drank 1% sodium chloride/0.2% potassium chloride solutions. Sham-operated rats received only uninephrectomy and drank tap water. Three to 4 weeks later, arterial and venous catheters were implanted for measurements of arterial and central venous pressures, respectively, and a silicone balloon catheter was permanently fixed in the right atrium to produce brief circulatory arrest. Venous smooth muscle activity was estimated on the basis of repeated measurements of mean circulatory filling pressure in conscious rats resting in their home cages. DOCA-salt-treated rats were hypertensive and had elevated mean circulatory filling pressure compared with normotensive sham-operated rats. Blockade of the endothelin subtype A receptor with 1 mg/kg ABT-627 IV decreased arterial blood pressure and mean circulatory filling pressure significantly more in hypertensive rats than in normotensive rats. Ganglionic blockade with 30 mg/kg hexamethonium IV also decreased arterial blood pressure and mean circulatory filling pressure more in hypertensive than in normotensive rats. Pretreatment with ABT-627 did not affect subsequent hemodynamic responses to ganglionic blockade. We conclude that venous smooth muscle tone is increased in DOCA-salt hypertension through the independent actions of both endogenous endothelin-1 acting on subtype A receptors and sympathetically mediated venoconstrictor activity.

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“…It is unclear whether the increase in medial thickness is specific for renal hypertension; whereas Sudhir et al [9] did not find a difference in medial thickness of superficial forearm veins between subjects with essential hyperten sion and normotensive controls, Simon et al [10] ob served an increase in water and hexosamine content of the venous wall of hypertensive humans [10], Furthermore, an increase in medial thickness was ob served in hypertensive rats and dogs [11][12][13][14][15], Greenberg et al [11] observed an increase in mucopolysaccharides and glycoproteins in combination with medial smooth muscle cell hyperplasia in veins of spontaneously hyper tensive rats.…”

Section: Discussionmentioning

confidence: 99%

Morphological Changes of the Venous System in Uremic Patients

Kooman¹,

Daemen²,

Wijnen

et al. 1995

Nephron

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Because of the decreased venous compliance in hypertensive dialysis patients, it was investigated whether their venous system exhibited structural abnormalites. Venous samples were taken during transplantation from the common and external iliac vein in 12 hypertensive and 6 normotensive uremic patients and from the distal inferior caval vein and the common iliac vein in 7 kidney donors and 5 autopsy patients without history of cardiovascular disease. The thickness of the venous media was significantly increased in hypertensive uremic patients as compared to controls, but did not differ between normotensive patients and controls. The quantity of medial collagen did not differ among the various groups. The smooth muscle content of the media was increased in 5 uremic patients (2 normotensive and 3 hypertensive patients), whereas almost no smooth muscle was observed in the media of controls. Intimal thickening was observed neither in uremic patients nor in controls. In conclusion: increased medial thickness in hypertensive dialysis patients could be an explanation for the decreased venous compliance previously found in these patients.

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Venous Changes in Renal Hypertensive Rats: The Role of Humoral Factors

Cited by 7 publications

References 10 publications

Angiopathic serum factor in perinephritic hypertensive dogs.

Angiopathic serum factor in perinephritic hypertensive dogs.

Mechanisms of Increased Venous Smooth Muscle Tone in Desoxycorticosterone Acetate-Salt Hypertension

Morphological Changes of the Venous System in Uremic Patients

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