ABSTRACT
Background: Autonomic dysfunction (AD) is highly prevalent in hemodialysis (HD) patients and has been implicated in their increased risk of cardiovascular mortality. Objective: To correlate heart rate variability (HRV) during exercise treadmill test (ETT) with the values obtained when measuring functional aerobic impairment (FAI) in HD patients and controls. Methods: Cross-sectional study involving HD patients and a control group. Clinical examination, blood sampling, transthoracic echocardiogram, 24-hour Holter, and ETT were performed. A symptom-limited ramp treadmill protocol with active recovery was employed. Heart rate variability was evaluated in time domain at exercise and recovery periods. Results: Forty-one HD patients and 41 controls concluded the study. HD patients had higher FAI and lower HRV than controls (p<0.001 for both). A correlation was found between exercise HRV (SDNN) and FAI in both groups. This association was independent of age, sex, smoking, body mass index, diabetes, and clonidine or beta-blocker use, but not of hemoglobin levels. Conclusion: No association was found between FAI and HRV on 24-hour Holter or at the recovery period of ETT. Of note, exercise HRV was inversely correlated with FAI in HD patients and controls. (Arq Bras Cardiol. 2015; [online]. ahead print, PP.0-0) .
Fundamento: A disfunção autonômica (DA) é altamente prevalente em pacientes em hemodiálise (HD) e tem sido implicada no risco aumentado de mortalidade cardiovascular. Objetivo: Correlacionar a variabilidade RR (VRR) durante o teste ergométrico (TE) com o déficit funcional aeróbico (FAI) em pacientes em HD e em um grupo controle. Métodos: Trata-se de um estudo transversal no qual as variáveis analisadas foram obtidas através de exame clínico, coleta de sangue, ecocardiograma transtorácico, Holter de 24 horas e TE. Foi realizado TE em esteira pelo protocolo de rampa, limitado por sintomas, com recuperação ativa. A VRR foi avaliada no domínio do tempo no exercício e na recuperação separadamente. Resultados: Quarenta e um pacientes em HD e 41 controles concluíram o estudo. Pacientes em HD tinham maior FAI e menor VRR do que os controles (p <0,001 para ambos). Houve correlação entre FAI e VRR no exercício (SDNN) em ambos os grupos. Esta associação foi independente de idade, sexo, tabagismo, índice de massa corporal, diabetes, clonidina, betabloqueador, mas não dos níveis de hemoglobina. Conclusão: A VRR no exercício foi inversamente correlacionada com o FAI em pacientes em HD e controles. Não foram observadas associações do FAI com VRR no Holter ou no período de recuperação do TE. .
Subject(s)
Animals , Mice , Colitis/pathology , Colonic Neoplasms/pathology , Fatty Acid Desaturases/genetics , Fatty Acid Desaturases/physiology , Apoptosis , /biosynthesis , /biosynthesis , Antineoplastic Agents/metabolism , /metabolism , Colitis/genetics , Colonic Neoplasms/genetics , Fatty Acids, Unsaturated/metabolism , Lymphocytes/metabolism , Mice, Transgenic , Phospholipids/metabolismABSTRACT
Animal biosynthesis of high polyunsaturated fatty acids from linoleic, alpha-linolenic and oleic acids is mainly modulated by the delta6 and delta5 desaturases through dietary and hormonal stimulated mechanisms. From hormones, only insulin activates both enzymes. In experimental diabetes mellitus type-1, the depressed delta6 desaturase is restored by insulin stimulation of the gene expression of its mRNA. However, cAMP or cycloheximide injection prevents this effect. The depression of delta6 and delta5 desaturases in diabetes is rapidly correlated by lower contents of arachidonic acid and higher contents of linoleic in almost all the tissues except brain. However, docosahexaenoic n-3 acid enhancement, mainly in liver phospholipids, is not explained yet. In experimental non-insulin dependent diabetes, the effect upon the delta6 and delta5 desaturases is not clear. From all other hormones glucagon, adrenaline, glucocorticoids, mineralocorticoids, oestriol, oestradiol, testosterone and ACTH depress both desaturases, and a few hormones: progesterone, cortexolone and pregnanediol are inactive.