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Lymphatic Vascular Integrity is Disrupted in a Mouse Model of Diabetes: Dual Regulation by Nitric Oxide
Author(s) -
Scallan Joshua P,
Hill Michael A,
Davis Michael J
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.950.9
Subject(s) - lymphatic system , nitric oxide , lymphatic vessel , vascular permeability , endocrinology , medicine , diabetes mellitus , chemistry , enos , nitric oxide synthase , pathology , cancer , metastasis
Emerging studies support the idea that metabolic diseases such as hypercholesterolemia and obesity are associated with compromised lymphatic vessel function. Whether, or how, insulin‐resistant diabetes affects the lymphatic vasculature remains unexplored. To test the hypothesis that lymphatic vascular integrity is disrupted in diabetes, we developed an innovative approach to measure the permeability of collecting lymphatics from wild‐type (WT) and leptin receptor‐deficient (db/db) mice. Vessels were isolated and mounted on glass micropipettes that could switch repeatedly between perfusion of fluorescent‐labeled or unlabeled albumin solutions. The accumulation of fluorescent albumin outside the vessel was measured over time with photometry, while diameter was monitored simultaneously on a near infrared image. Since nitric oxide (NO) is crucial for maintaining blood vessel integrity and is impaired in diabetes, we first determined whether NO was capable of regulating lymphatic permeability (×10(−7) cm/s). WT lymphatic permeability (3.3±0.7, n=7) was significantly reduced by pharmacologic inhibition (0.6±0.2, n=7) or genetic deletion (0.6±0.1, n=6) of endothelial nitric oxide synthase (eNOS). Histamine, an agent known to elicit endogenous NO production (21±7, n=7), or sodium nitroprusside, an exogenous NO donor (20±5, n=6), both significantly elevated WT lymphatic permeability. Collecting lymphatics from db/db mice exhibited a dramatic increase in permeability compared to age‐matched 25‐week old controls (WT: 2.2±0.3, n=10; db/db: 299±56, n=23). Interestingly, restoration of NO production by acute exposure to L‐arginine rescued this endothelial barrier dysfunction, and could be reversed by pharmacologic inhibition of eNOS with L‐NAME (db/db: 321±84, L‐arginine: 14±5, L‐arginine+L‐NAME: 297±88; n=9). In summary, this approach enables quantitative measurement of lymphatic integrity in transgenic mice for the first time and identified a lymphatic defect in diabetic mice caused by reduced NO bioavailability. Support or Funding Information This work was supported by the National Heart, Lung, and Blood Institute at the National Institutes of Health (K99 HL124142 to J.P.S., R01 HL089784 and R01 HL120867 to M.J.D., P01 HL095486 to M.J.D. and M.A.H., and R01 HL085119 to M.A.H.)