title: Postural variation of pulmonary diffusing capacity as a marker of lung microangiopathy in Indian patients with type 2 diabetes mellitus.
abstract: BACKGROUND
  Diabetes mellitus (DM) is characterized by the presence of chronic hyperglycemia and formation of advanced glycation end products (AGEs). Interaction between AGE and its receptor leads to endothelial damage and microangiopathy. This study was undertaken to investigate the possibility of using a postural variation of diffusing capacity as an early marker of lung microangiopathy and its correlation with the level of adhesion molecules, HbA1c, duration of diabetes, and insulin resistance in type 2 DM (T2DM) patients with and without microangiopathy.
  
  
  METHODS
  Forty patients having T2DM without any microangiopathy (n = 20) as well as with microangiopathy (n = 20), and 22 age and sex matched healthy controls were enrolled in this cross-sectional study. Measurement of lung volumes and capacities were done. DLco was measured in sitting and supine position. Levels of vascular cell adhesion molecule-1 (VCAM-1), E-selectin, fasting glucose, and insulin were estimated in plasma of the patients and compared with controls.
  
  
  RESULTS
  Restrictive type of ventilatory change was observed in DM patients. Diffusing capacity (% predicted) in the supine position (P < 0.0001), postural change in DLco (P < 0.0001), and coefficient of diffusion were significantly less in DM patients as compared to controls. Plasma levels of VCAM-1 were significantly higher in DM patients without microangiopathy and negatively correlated (r = -0.4054, P = 0.0094) with Δ DLco in all diabetic subjects. All patients had significantly higher insulin resistance.
  
  
  CONCLUSIONS
  Lack of postural increase in diffusing capacity in type 2 diabetic patients along with increased VCAM-1 levels could reflect the presence of an early microangiopathy of the small pulmonary vessels.
authors.affiliation: Department of Physiology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Avinash
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Department of Physiology, Dr. Babasaheb Ambedkar Medical College, Rohini, New Delhi, India.
authors.forename: Geetanjali
authors.initials: G
authors.lastname: Bade
authors.affiliation: Department of Physiology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Anjali
authors.initials: A
authors.lastname: Trivedi
authors.affiliation: epartment of Endocrinology and Metabolism, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Viveka P
authors.initials: VP
authors.lastname: Jyotsna
authors.affiliation: Department of Physiology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Anjana
authors.initials: A
authors.lastname: Talwar
keywords: Adhesion molecules; diabetes mellitus; diffusing capacity; microangiopathy