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Sodium-lithium countertransport and cardiorenal abnormalities in essential hypertension
R Nosadini1, A Semplicini, P Fioretto
1Department of Internal Medicine, Università di Padova, Italy.
Insights
Elevated sodium-lithium countertransport in hypertension is linked to increased kidney filtration, albumin excretion, and cardiac changes. This suggests a specific pathway in essential hypertension affecting renal and cardiac health.
Area of Science:
- Nephrology
- Cardiology
- Hypertension Research
Background:
- Essential hypertension affects a significant portion of the population, with varying underlying physiological mechanisms.
- Red blood cell sodium-lithium countertransport is a known marker, but its specific association with organ damage in hypertension is not fully elucidated.
Purpose of the Study:
- To investigate the differences in renal and cardiac function and morphology between hypertensive patients with high versus normal sodium-lithium countertransport activity.
- To compare these parameters with a normotensive control group.
Main Methods:
- Comparison of two groups of hypertensive patients (n=23 high, n=22 normal sodium-lithium countertransport) and a normotensive control group (n=21).
- Assessment of glomerular filtration rate, albumin excretion rate, kidney volume, lithium clearance, total body exchangeable sodium, left ventricular mass index, and cardiac wall thickness.
- Groups were matched for age, sex, BMI, smoking, hypertension duration, and blood pressure levels.
Main Results:
- Patients with high sodium-lithium countertransport exhibited elevated glomerular filtration rate, albumin excretion rate, and kidney volume.
- These patients also showed lower lithium clearance, higher total body exchangeable sodium, and increased left ventricular mass index and cardiac wall thickness.
- Hypertensive patients with normal countertransport had parameters similar to normotensive controls, except for higher GFR and LVMI.
Conclusions:
- Elevated sodium-lithium countertransport in essential hypertension is associated with markers of increased renal workload and cardiac remodeling.
- This suggests that sodium-lithium countertransport activity may identify a subgroup of hypertensive patients at higher risk for renal and cardiac complications.
- Further research is warranted to explore the therapeutic implications of targeting this pathway.
Abstract:
The rate of red blood cell sodium-lithium countertransport is elevated only in a subgroup of patients with essential hypertension. We have therefore compared renal and cardiac function and morphology in two groups of hypertensive patients with high (n = 23) or normal (n = 22) sodium-lithium countertransport (mean +/- SEM: 0.61 +/- 0.10 versus 0.29 +/- 0.07 mmol/l red blood cells.hr). The two groups were similar in age, sex distribution, body mass index, smoking habit, duration of hypertension, and actual levels of untreated blood pressure. Hypertensive patients with elevated sodium-lithium countertransport activity showed elevated glomerular filtration rate (118 +/- 2 versus 109 +/- 2 ml/min.1.73 m2; p less than 0.001), albumin excretion rate (23 +/- 3 versus 14 +/- 2 micrograms/min; p less than 0.001), larger kidney volume (250 +/- 15 versus 203 +/- 13 ml.1.73 m2; p less than 0.01), lower lithium clearance rate (26.7 +/- 0.3 versus 28.9 +/- 0.3 ml/min.1.73 m2; p less than 0.01), and higher total body exchangeable sodium (2,716 +/- 33 versus 2,485 +/- 41 mmol.1.73 m2; p less than 0.01). Left ventricular mass index (139 +/- 6 versus 119 +/- 6 g/m2; p less than 0.05), relative wall thickness (0.39 +/- 0.05 versus 0.29 +/- 0.04 cm; p less than 0.001), and left posterior wall plus intraventricular septum thickness (2.02 +/- 0.04 versus 1.76 +/- 0.03 cm; p less than 0.05) were also higher in patients with high sodium-lithium countertransport. Hypertensive patients with normal sodium-lithium countertransport had renal and cardiac parameters similar to those of a normotensive control group (n = 21) except for a higher glomerular filtration rate and left ventricular mass index.(ABSTRACT TRUNCATED AT 250 WORDS)