TY - JOUR
T1 - Noninvasive assessment of alveolar microvascular recruitment in conscious non-sedated rats
AU - Yilmaz, Cuneyt
AU - Dane, Dan M.
AU - Ravikumar, Priya
AU - Unger, Roger H
AU - Hsia, Connie C
N1 - Funding Information:
The authors thank Dennis J. Bellotto for technical assistance, and the staff of the Animal Resources Center at the University of Texas Southwestern Medical Center for veterinary assistance. This research was supported by Grants from the American Lung Association RG-170442-N (CY) , the National Institute of Diabetes and Digestive and Kidney Diseases DK-063242 (CCH) , and the National Heart, Lung and Blood Institute Grants RO1 HL40070 and UO1 HL111146 (CCH) . The contents of this article are solely the responsibility of the authors and do not necessarily represent the official views of the National Heart, Lung, and Blood Institute or of the National Institutes of Health .
PY - 2014/1/1
Y1 - 2014/1/1
N2 - Recruitment of alveolar microvascular reserves, assessed from the relationship between pulmonary diffusing capacity (DLCO) and perfusion (Q̇c), is critical to the maintenance of arterial blood oxygenation. Leptin-resistant ZDF fatty diabetic (fa/fa) rats exhibit restricted cardiopulmonary physiology under anesthesia. To assess alveolar microvascular function in conscious, non-sedated, non-instrumented, and minimally restrained animals, we adapted a rebreathing technique to study fa/fa and control non-diabetic (+/+) rats (4-5 and 7-11mo old) at rest and during mild spontaneous activity. Measurements included O2 uptake, lung volume, Q̇c, DLCO, membrane diffusing capacity (DMCO), capillary blood volume (Vc) and septal tissue-blood volume. In older fa/fa than +/+ animals, DLCO and DMCO at a given Q̇c were lower; Vc was reduced in proportion to Q̇c. Results demonstrate the consequences of alveolar microangiopathy in the metabolic syndrome: lung volume restriction, reduced Q̇c, and elevated membrane resistance to diffusion. At a given Q̇c, DLCO is lower in rats and guinea pigs than dogs or humans, consistent with limited alveolar microvascular reserves in small animals.
AB - Recruitment of alveolar microvascular reserves, assessed from the relationship between pulmonary diffusing capacity (DLCO) and perfusion (Q̇c), is critical to the maintenance of arterial blood oxygenation. Leptin-resistant ZDF fatty diabetic (fa/fa) rats exhibit restricted cardiopulmonary physiology under anesthesia. To assess alveolar microvascular function in conscious, non-sedated, non-instrumented, and minimally restrained animals, we adapted a rebreathing technique to study fa/fa and control non-diabetic (+/+) rats (4-5 and 7-11mo old) at rest and during mild spontaneous activity. Measurements included O2 uptake, lung volume, Q̇c, DLCO, membrane diffusing capacity (DMCO), capillary blood volume (Vc) and septal tissue-blood volume. In older fa/fa than +/+ animals, DLCO and DMCO at a given Q̇c were lower; Vc was reduced in proportion to Q̇c. Results demonstrate the consequences of alveolar microangiopathy in the metabolic syndrome: lung volume restriction, reduced Q̇c, and elevated membrane resistance to diffusion. At a given Q̇c, DLCO is lower in rats and guinea pigs than dogs or humans, consistent with limited alveolar microvascular reserves in small animals.
KW - Alveolar microangiopathy
KW - Lung diffusing capacity
KW - Metabolic syndrome
KW - Obesity
KW - Pulmonary blood flow
KW - Type-2 diabetes mellitus
UR - http://www.scopus.com/inward/record.url?scp=84887148202&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84887148202&partnerID=8YFLogxK
U2 - 10.1016/j.resp.2013.09.010
DO - 10.1016/j.resp.2013.09.010
M3 - Article
C2 - 24100202
AN - SCOPUS:84887148202
SN - 1569-9048
VL - 190
SP - 105
EP - 112
JO - Respiratory Physiology and Neurobiology
JF - Respiratory Physiology and Neurobiology
IS - 1
ER -