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[Calcium pump changes in patients with essential arterial hypertension]
J Sobrino1, A de la Sierra, M T Aguilera
1Servicio de Medicina Interna, Hospital de l'Esperit Sant, Santa Coloma de Gramenet, Barcelona.
Medicina Clinica
|May 13, 1999
Summary
Essential hypertensive patients may have abnormalities in the calcium (Ca2+) pump, a key transporter. About a third of patients show impaired Ca2+ ATPase function, linked to higher age and kidney/uric acid levels.
Area of Science:
- Cardiovascular Physiology
- Biochemistry
- Nephrology
Background:
- Transmembrane Ca2+ fluxes are crucial for cellular function.
- The Ca2+-dependent ATPase plays a significant role in regulating intracellular Ca2+ levels.
- Elevated cytosolic Ca2+ has been observed in essential hypertension.
Purpose of the Study:
- To investigate the kinetics of the Ca2+ pump in erythrocytes of essential hypertensive patients.
- To determine if abnormalities in Ca2+ transport are associated with hypertension.
- To identify subgroups of hypertensive patients with specific ion transport defects.
Main Methods:
- Kinetic study of the Ca2+ pump using strontium (Sr2+) as a calcium analogue in intact erythrocytes.
- Analysis of 49 essential hypertensive patients and 27 normotensive controls.
- Intracellular Ca2+ and Sr2+ concentrations modulated using the A-23187 ionophore.
Main Results:
- Hypertensive patients exhibited a significantly increased maximal efflux rate (Vmax) for Sr2+ compared to controls.
- Mean values for the apparent dissociation constant for intracellular Ca2+ (KCa) were also elevated in essential hypertensives.
- A subgroup of 32.6% of hypertensive patients showed increased KCa values, correlating with higher age, serum creatinine, and uric acid levels, and also higher Vmax.
Conclusions:
- Essential hypertensive patients display heterogeneity in ion transport abnormalities.
- Abnormalities of the Ca2+-dependent ATPase were identified in approximately 33% of essential hypertensive patients.
- These patients with Ca2+ pump dysfunction are typically older and have elevated serum creatinine and uric acid levels.