Urinary kallikrein in hypertension secondary to hemolytic uremic syndrome: response to diuretic stimulus
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Children with a history of hemolytic uremic syndrome (HUS) showed varied urinary kallikrein responses to diuretics. Normotensive children experienced a significant increase, unlike hypertensive children, suggesting altered vasodilator system reactivity.
Area of Science:
- Pediatric Nephrology
- Hypertension Research
- Urology
Background:
- Hemolytic uremic syndrome (HUS) can lead to long-term renal complications, including hypertension.
- The kallikrein-kinin system plays a role in regulating blood pressure and vascular tone.
- Investigating vasodilator system function in HUS survivors is crucial for understanding post-HUS hypertension.
Purpose of the Study:
- To assess urinary kallikrein excretion in children with a history of HUS.
- To compare kallikrein excretion between normotensive and hypertensive HUS survivors.
- To evaluate the effect of diuretic administration on kallikrein excretion in these children.
Main Methods:
- Urinary kallikrein excretion was measured in 43 children with a history of HUS (mean age 8 years).
- Children were categorized into normotensive (n=28) and hypertensive (n=15) groups.
- A subset of 23 children received hydrochlorothiazide and amiloride for ten days to assess diuretic response.
Main Results:
- No significant difference in baseline urinary kallikrein excretion was observed between normotensive and hypertensive HUS survivors.
- Administration of hydrochlorothiazide plus amiloride resulted in a threefold increase in urinary kallikrein excretion in normotensive children.
- Urinary kallikrein excretion remained unchanged in hypertensive children following diuretic administration.
Conclusions:
- Diuretic administration reveals distinct responses in the kallikrein-kinin system between normotensive and hypertensive children with a history of HUS.
- These differential responses may indicate altered reactive capabilities of the vasodilator system in HUS-associated hypertension.
- Further research is warranted to elucidate the role of the kallikrein-kinin system in the pathogenesis of hypertension post-HUS.
Abstract:
Urinary kallikrein excretion was measured in 43 children, mean age 8 years, who had the hemolytic uremic syndrome (HUS) during the first year of life. Twenty eight were normotensive and fifteen hypertensive. We found no difference in urinary kallikrein excretion between the normotensive and hypertensive groups. Twenty three of these children received a combination of 1 mg/kg/day of hydrochlorothiazide plus amiloride for ten days. 14 of these patients were normotensive and 9 hypertensive. The rate of kallikrein excretion did not change in the hypertensive children whereas normotensive children had a three fold increase following administration of the diuretic. The different behaviour of kallikrein excretion in both groups may reflect a change in the reactive capabilities of the vasodilator system in this form of hypertension.