• Tereza Maria Dantas de Medeiros, Katia Coelho Ortega, Décio Mion, Kimiyo Nonoyama, and Orlando Cesar de Oliveira Barretto.
• LIM-234 and LIM-40, Hospital das Clinicas, Faculty of medicine, Universidade de São Paulo, São Paulo, Brazil.
• Sao Paulo Med J. 2002 Jan 3; 120 (1): 585-8.

ContextIt has been reported that the equilibrium between the erythrocyte protease calpain I and its physiological inhibitor calpastatin is disrupted in patients with essential hypertension.ObjectiveTo investigate the activity of non-purified calpain I in hemolysates against the erythrocytic membrane proteins, rather than against other substrates.DesignEvaluation of calpain I red cell activity upon its own physiological substrates in hypertensive patients, in a near-physiological environment.SettingLIM-23 and LIM-40 of Hospital das Clinicas of the Faculty of Medicine of USP.SamplePatients with moderate primary hypertension over 21 years of age who were given amlodipine (n:10) and captopril (n:10) for 8 weeks, plus normal controls (n:10).Main MeasurementsRed cell membrane proteins were incubated with and without protease inhibitors and with and without calcium chloride and underwent polyacrylamide gel electrophoresis.ResultsDigestion of bands 2.1 and 4.1 was observed, indicating calpain I activity. No statistical differences regarding bands 2.1 and 4.1 were observed before treatment, between the controls and the hypertensive patients, either in ghosts prepared without calcium or with increasing concentrations of calcium. Nor were statistical differences observed after treatment, between the controls and the patients treated with amlodipine and captopril, or between the patients before and after treatment with both drugs.ConclusionThe final activity of non-purified calpain I upon its own physiological substrate, which was the approach utilized in this study, may more adequately reflect what happens in red cells. Under such conditions no imbalance favoring calpain I activity increase was observed. The protective factor provided by calpastatin against calpain I activity may diminish under hypertension.

24 keywords...

hide…