Related Experiment Video
Updated: Jul 17, 2026
A Delayed Inoculation Model of Chronic Pseudomonas aeruginosa Wound Infection
Published on: February 20, 2020
Delayed elevation of ED1-cellular fibronectin in plasma following postsurgical bacteremia
T A Rizk1, R A Rebres, P A Vincent
1Department of Physiology and Cell Biology, Albany Medical College of Union University, New York 12208.
Abstract:
Fibronectin (Fn) exists in both a soluble form in plasma and lymph as well as an insoluble form in the extracellular matrix. Matrix-localized cellular fibronectin (cFn) contains extra domains (ED1 and/or ED2) not found in plasma Fn (pFn). Very little (< 1-2%) ED1-containing cFn exists in normal blood, and its rapid release into plasma and/or lymph is believed to reflect acute vascular injury. We used a polyclonal antibody to sheep pFn and a monoclonal antibody to ED1 domain of cFn to measure both pFn and ED1-cFn in relationship to lung lymph flow (QL), lung lymph-to-plasma (L/P) total protein concentration ratio, and lung protein clearance (LPC). Unanesthetized sheep (n = 7) were injected intravenously with Pseudomonas aeruginosa (5 x 10(8)) at both 2 and 7 days following surgical preparation of a lung lymph fistula. After both bacterial challenges, we observed an early increase in QL and a small decline in the L/P ratio (0-2 h), reflecting increased fluid filtration in the presence of an intact vascular barrier. This was followed by a further increase (P < 0.05) in QL; an elevation in the L/P ratio; and a marked (P < 0.05) increase in LPC over 3-6 h, indicative of an increase in lung endothelial protein permeability. Before the first bacterial infusion, ED1-cFn in plasma was 9.97 micrograms/ml or approximately 2% of the total Fn antigen in plasma; whereas ED1-cFn in lung lymph was 6-8% of total lymph Fn.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Acute vascular injury in sheep increased lung lymph flow and protein clearance. Cellular fibronectin (ED1-cFn) release into plasma indicated increased lung endothelial permeability following Pseudomonas aeruginosa challenge.
Area of Science:
- Physiology
- Immunology
- Biochemistry
Background:
- Fibronectin (Fn) exists in plasma (pFn) and extracellular matrix (cFn).
- Cellular fibronectin (cFn) contains extra domains (ED1/ED2) absent in plasma Fn (pFn).
- ED1-containing cFn in blood (<1-2%) suggests acute vascular injury upon release.
Purpose of the Study:
- To measure plasma and lymph fibronectin levels in relation to lung lymph flow (QL), lymph-to-plasma protein ratio (L/P), and protein clearance (LPC).
- To assess the role of ED1-containing cellular fibronectin (ED1-cFn) as a marker of lung endothelial permeability.
Main Methods:
- Unanesthetized sheep (n=7) with lung lymph fistulas were challenged with Pseudomonas aeruginosa intravenously.
- Polyclonal antibody to sheep pFn and monoclonal antibody to ED1 domain of cFn were used for measurements.
- Measurements of QL, L/P ratio, and LPC were taken over time post-challenge.
Main Results:
- Bacterial challenge caused an early increase in QL and a slight L/P ratio decline (0-2h), indicating fluid filtration.
- Later, QL further increased, L/P ratio elevated, and lung protein clearance (LPC) markedly increased (3-6h), signifying increased endothelial permeability.
- Pre-challenge, ED1-cFn was ~2% of total plasma Fn and 6-8% of total lymph Fn.
Conclusions:
- Pseudomonas aeruginosa challenge increases lung endothelial protein permeability in sheep.
- Elevated lung protein clearance and lymph flow indicate significant vascular injury.
- ED1-cFn release into plasma and lymph correlates with increased lung endothelial permeability.
