title: Trained breathing-induced oxygenation acutely reverses cardiovascular autonomic dysfunction in patients with type 2 diabetes and renal disease.
abstract: OBJECTIVE
  Cardiovascular autonomic dysfunction, evaluated as baroreflex sensitivity (BRS), could be acutely corrected by slow breathing or oxygen administration in patients with type 1 diabetes, thus suggesting a functional component of the disorder. We tested this hypothesis in patients with the type 2 diabetes with or without renal impairment.
  
  
  METHODS
  Twenty-six patients with type 2 diabetes (aged 61.0 ± 0.8 years, mean ± SEM; duration of diabetes 10.5 ± 2 years, BMI 29.9 ± 0.7 kg/m(2), GFR 68.1 ± 5.6 ml/min) and 24 healthy controls (aged 58.5 ± 1.0 years) were studied. BRS was obtained from recordings of RR interval and systolic blood pressure fluctuations during spontaneous and during slow, deep (6 breaths/min) controlled breathing in conditions of normoxia or hyperoxia (5 l/min oxygen).
  
  
  RESULTS
  During spontaneous breathing, diabetic patients had lower RR interval and lower BRS compared with the control subjects (7.1 ± 1.2 vs. 12.6 ± 2.0 ms/mmHg, p < 0.025). Deep breathing and oxygen administration significantly increased arterial saturation, reduced RR interval and increased BRS in both groups (to 9.6 ± 1.8 and 15.4 ± 2.4 ms/mmHg, respectively, p < 0.05, hyperoxia vs. normoxia). Twelve diabetic patients affected by chronic diabetic kidney disease (DKD) presented a significant improvement in the BRS during slow breathing and hyperoxia (p < 0.025 vs. spontaneous breathing during normoxia).
  
  
  CONCLUSIONS
  Autonomic dysfunction present in patients with type 2 diabetes can be partially reversed by slow breathing, suggesting a functional role of hypoxia, also in patients with DKD. Interventions known to relieve tissue hypoxia and improve autonomic function, like physical activity, may be useful in the prevention and management of complications in patients with diabetes.
authors.affiliation: Department of Nephrology, Dialysis and Transplantation, Fondazione IRCCS Policlinico San Matteo and University of Pavia, Piazzale Golgi 19, 27100, Pavia, Italy. pasqualeesposito@hotmail.com.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Esposito
authors.affiliation: Department of Internal Medicine, Fondazione IRCCS Policlinico San Matteo and University of Pavia, Pavia, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Mereu
authors.affiliation: Department of Internal Medicine, Fondazione IRCCS Policlinico San Matteo and University of Pavia, Pavia, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: De Barbieri
authors.affiliation: Department of Nephrology, Dialysis and Transplantation, Fondazione IRCCS Policlinico San Matteo and University of Pavia, Piazzale Golgi 19, 27100, Pavia, Italy.
authors.forename: Teresa
authors.initials: T
authors.lastname: Rampino
authors.affiliation: Department of Internal Medicine, Fondazione IRCCS Policlinico San Matteo and University of Pavia, Pavia, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Di Toro
authors.affiliation: Division of Nephrology, Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland.|Folkhälsan Institute of Genetics, Folkhälsan Research Center Biomedicum Helsinki, Helsinki, Finland.|Baker ID Heart and Diabetes Institute, Melbourne, Australia.
authors.forename: Per-Henrik
authors.initials: PH
authors.lastname: Groop
authors.affiliation: Department of Nephrology, Dialysis and Transplantation, Fondazione IRCCS Policlinico San Matteo and University of Pavia, Piazzale Golgi 19, 27100, Pavia, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Dal Canton
authors.affiliation: Department of Internal Medicine, Fondazione IRCCS Policlinico San Matteo and University of Pavia, Pavia, Italy.|Folkhälsan Institute of Genetics, Folkhälsan Research Center Biomedicum Helsinki, Helsinki, Finland.
authors.forename: Luciano
authors.initials: L
authors.lastname: Bernardi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001342:Autonomic Nervous System Diseases / Q000378:metabolism / Q000628:therapy*; D017704:Baroreflex; D001794:Blood Pressure; D001945:Breathing Exercises; D002318:Cardiovascular Diseases / Q000378:metabolism / Q000628:therapy*; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism / Q000628:therapy*; D003928:Diabetic Nephropathies / Q000378:metabolism / Q000628:therapy*; D005260:Female; D006801:Humans; D018496:Hyperoxia; D000860:Hypoxia / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood / Q000627:therapeutic use; D010101:Oxygen Consumption; D012119:Respiration; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: Baroreflex sensitivity; Cardiovascular autonomic neuropathy; Diabetic kidney disease; Hypoxia; Oxygen; Type 2 diabetes mellitus