[The level of endothelin-1 and reactivity of skin microvessels in patients with early stages of chronic kidney disease].

Aim: To evaluate endothelin-1 (ET-1) levels and to characterize reflex vasomotor reactions of skin vessels in distant exposure to cold in patients with chronic kidney disease (CKD) of stage I and II.

Material And Methods: Glomerular filtration rate (GFR) was calculated by MDRD formula for 40 healthy subjects (mean age 39.2 +/- 2.0 years) and 147 CKD patients (mean age 41.4 +/- 1.8 years). All the patients were also exposed to the cold test (a modified variant).

Results: Patients with CKD stage I demonstrated a 35.1% fall in blood flow rate (Qas) in response to cold stimulus, patients of stage II--a 42.2% fall, healthy patients--a 19.3%. CKD patients of stage I and II retained a Qas fall for 3 min after exposure to cold, while healthy subjects resumed skin blood circulation immediately after exposure to cold. Blood plasma ET-1 concentration in healthy subjects was 0.239 +/- 0.055 fmol/ml, in stage I CKD patients--0.334 +/- 0.066 fmol/l, in stage II CKD patients--0.422 +/- 0.041 fmol/l. Relationships were found between ET-1 level and GFR (Rs = 0.242; p < 0.05), 24 h proteinuria (Rs = 0.375; p < 0.003) and Qas% in the cold test (Rs = -0.389; p < 0.003) as well as time of recovery of the background Qas (Rs = -0.311; p < 0.003).

Conclusion: Dysfunction of autonomic nervous system at early stages of CKD may arise by means of activation of ET-1 synthesis in response to enhancement of sympathetic impacts.